Download silent, sleepy, but resilient microbes for environmental sustainability

INAUGURAL LECTURE
SILENT, SLEEPY, BUT RESILIENT MICROBES FOR
ENVIRONMENTAL SUSTAINABILITY
INTRODUCTION
This day, to the glory of God is, indeed memorable in the odyssey of my academic career in
the University of Lagos as I present myself before this august audience to deliver my
Inaugural lecture. The Inaugural lecture is a debt I consider important to pay and duly, to my
employers, the University of Lagos.
Mr. Vice-Chancellor, Sir, I am very happy that the Almighty God has made this day possible
and we are glad indeed.
I decided on this topic because microbes are cosmopolitan and yet cannot be seen with the
naked eye. They are of great benefits to humankind through their roles in the biogeochemical
cycling of wastes, food processing, human health, agriculture and wastewater treatment. They
are also significant in environmental quality through their activities in bioremediation of oil
spills and pollutants in different ecosystems.
SLEEPY MICROBES
Microbes make the human person. Individual beings are made up of communities of
microbes. The traditional view is that a human body is a collection of ten trillion cells, which
are themselves the product of 23,000 genes. If this is correct, these numbers underestimate
the truth, for in the organs especially the gut, dwell the microbiome, one hundred trillion
bacteria of several species bearing three million non-human genes. Thus, humans can be
considered as super- organisms made up of lots of smaller organisms which work together. It
might be perverse to claim that bacterial cells and genes are part of the body. My esteemed
audience, be the judge! The bugs are neither parasites nor passengers. They are rather fully
paid-up members of a community which the human “host” is but a single member.
RESILIENT
Microbes are resilient organisms able to withstand or recover quickly from difficult
conditions. They are capable of adapting to harsh unwelcoming environments and are able to
colonize any surface that contains adequate nutrients and moisture. Microbiology of space
exploration deals with the study of exploring the microbial aspects of space. Space is the void
that exists between the celestial bodies, including Earth (Poudrier, 2003). Microbes are
naturally introduced into space by suspension into the atmosphere and are later drawn into
space by mechanisms which involve ejecta arising from the collision of a planetary body with
meteorite powder. Artificially, spacecraft can unintentionally introduce terrestrial
microorganisms to space. They are able to survive extreme space factors due to the protection
of their Deoxyribonucleic acid (DNA) by small proteins and/or the high level of resistance of
their endospores. Examples of microbes found in space are: Deinococccus radiodurans,
Micrococcus spp., Staphylococcus epidermidis, Salmonella spp., Thermococcus sp.,
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Rhodococcus sp., Synechoccus sp., Xanthoria elegans, Bacillus simplex, Pseudomonas
aeruginosa etc.
SILENT MICROBES
Microbes have shaped our world. There are those that spring surprises, and some that threaten
us; there are those on whom we depend in many cases for our continued existence and those
that could help to shape our future, there are malevolent and benevolent microbes. Many
scientists are commemorated in the names of microorganisms that they studied. Salmonella
records the work of American veterinarian, Daniel Salmon who developed a vaccine against
hog cholera. In other cases, the name records the disease an organism causes as with
Mycobacterium tuberculosis or a chemical process that it promotes as with Clostridium
acetobutylicum. Such organisms and their microbial cousins have an influence on life that is
wholly disproportionate to their dimensions and invisibility. A small bacterium weighs as
little as 0.000000000001 (1x
) g, while a blue whale weighs about 100,000,000 (1x 108)
g. Yet a bacterium can kill a whale!
THE ENVIRONMENT
Those who spoke on environmental issues a few years ago were considered “way-out”.
Today environmental concerns have become respectable and included in the programs of
most organizations responsible for primary production through agriculture, forestry and
mining. The “theme” for the lecture given on World Environment Day on 5th June, 2013
“Think, Eat and Save” (TES) aptly given by Alhaji Gbolahan A. Solabi (GAS) captures the
idea of “From Farm to Table to save the Environment.” The environment is our common
heritage. It consists of natural resources (land, water, flora and fauna as well as microbes).
Continuing human survival depends on the sustenance of the environment. How did planet
Earth, and human society, come to be as they are today? Some of the prime movers that have
fashioned our world, our environment and our social structures are well recognized. They
range from the forces of inanimate nature and the cut and thrust of evolution, to the influence
of political, religious and military leaders and movements. However, our history and that of
the Earth itself, owe at least as much to the massive and multifarious activities of microbes.
MICROBES
By definition, a microbe is an organism so small that it can be seen only under the
microscope. In that sense we and most of the other animals, plants and other varieties of life
on our planet all started life as microbes. However large or complex, a fully grown organism
may be, each originated from a single fertilized egg cell, invisible to the naked eye. Microbes
have developed mechanisms for excreting waste materials across the cell membrane into the
environment, whereas humans require specialized organs such as the kidney to effect similar
processes. Even then, human activities are implicated in environmental pollution.
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Chrysobacterium indoligenes
Salmonella sp. (causes food poisoning)
Streptomyces spp.
Fusarium sp.
SLEEPING BEAUTIES! PLEASE BE CAREFUL NOT TO WAKE THEM!
Our perception of bacteria as unicellular life forms is deeply rooted in the pure-culture
paradigm. Since bacteria can, in a strict sense, be diluted to a single cell and studied in liquid
culture, this mode of operation has been exploited and used to study many bacterial activities.
Although this traditional way of culturing bacteria in liquid medium has been instrumental in
the study of microbial pathogenesis and enlightening as to some of the amazing facets of
microbial physiology, pure culture planktonic growth is not how bacteria exist in nature. For
example, environmental microbiologists have long recognized that complex bacterial
communities are responsible for driving the biogeochemical cycling that maintains the
biosphere (Makin and Beveridge, 1996). Until recently, the lack of methods for exploring
these communities in-situ has hampered detailed analyses. Fortunately, recent advances in
microscopy and molecular technologies have made it possible to examine such communities
in-situ in great detail and without the bias of liquid culture. Direct observation of a wide
variety of natural habitats has established that the majority of microbes are attached to
surfaces within a structured biofilm ecosystem and not as free-floating organisms (Costerton
et al., 1994). Moreover, it is becoming clear that these natural assemblages of bacteria within
the biofilm matrix function as a cooperative consortium, in a relatively complex and
coordinated manner (Caldwell and Costerton, 1995; Costerton et al., 1994).
In nature, bacteria rarely exist in isolation. They are active members of complex micro- and
macro-communities. Their survival is partly dependent on their ability to communicate
among themselves and/or between themselves and other organisms and their ability to sense
environmental changes and respond swiftly by altering expression of specific genes and
metabolic pathways. In addition to these basic stimulus-response events, bacteria can
communicate by producing and responding to small diffusible signal molecules termed
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autoinducers (AIs) (Antunes et al., 2010). Autoinducers are produced at basal levels and their
concentrations increase with bacterial growth. The diffusible nature of the signal molecules
allows their movement across cell membranes, such that, their concentrations inside cells
approximate the concentrations in the environment. Upon attaining critical concentration, the
signal molecules can bind to and activate receptors inside bacterial cells, which alter gene
expression to activate behaviour that is beneficial under the particular condition encountered.
This phenomenon, which occurs in a cell-density-dependent manner, has been termed
quorum sensing (QS) (Antunes and Ferreira, 2009., Bassler and Losick, 2006; Fuqua and
Greenberg, 2002).
Quorum sensing is defined as the capacity to detect extracellular, small-molecule signals and
to alter gene expression in response to bacterial population densities (Asad and Opal, 2008).
It involves four basic steps: 1. Production of small biochemical signal molecules by the
bacterial cell. 2. Release of the signal molecules, either actively or passively into the
surrounding environment. 3. Recognition of the signal molecules by specific receptors once a
threshold concentration has been exceeded. 4. Changes in gene regulation (Sifri, 2008).
BOUNDARIES OF MICROBIOLOGY
We live in paradoxical times: never before have the successes and powers of modern
technology been so apparent. Today, the breaking down of boundaries between disciplines
has become general. We find many Immunologists who have strayed into Genetics,
Geneticists in Biochemistry Department, Biochemists in Physiology Department, and
Molecular biologists everywhere. The complication appears to be universal and it teaches us
a lesson: disciplines exist only by virtue of the preconceived notions which we entertain
about them. In the Faculty of Science, we have an obligation to teach Science. The Science
of Microbiology is a dynamic discipline that covers an enormous territory in modern Biology,
in which there is exchange of knowledge between “Academia unilagii” and “Escherichia
studentii”. Ladies and gentlemen, the microbes will have the last word.
Biotechnology is also about keeping the environment clean. In developed countries, strict
laws govern the disposal of industrial, agricultural and domestic wastes or sewage on land or
into water systems. Waste management provides a service by exploiting microbial systems to
treat wastes, making them less harmful to the environment. The microbial metabolism is
used to degrade and transform harmful compounds to biologically acceptable ones. A byproduct of this process is the flammable gas, methane (CH4) which can be used as energy
source. Agricultural Microbiology is the paramount research field responsible for the transfer
of knowledge from general Microbiology and Microbial Ecology to the agricultural
biotechnologies. Emphasis is also on the importance of microorganisms in relation to
Agriculture and Environmental health (Nwokoye et al., 2012; Wang et al., 2009) and to the
biocontrol of phytopathogens (Ugoji and Laing, 2008; Mohammed et al., 2008., Ugoji et al.,
2005).
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RESEARCH CONTRIBUTIONS
Studies on soft rot of yams Dioscorea spp. in storage with reference to biochemical and
histological changes.
Enzymic localizations in yam tubers were carried out and correlated with their structures and
functions. Cytochrome oxidase is the most important enzyme because the major part of the
useful energy liberated by respiration is connected to the cytochrome system of which this
enzyme is the terminal component. Peroxidase is also present. There are strong reactions for
peroxidase in wound zones. It is also found in meristems, epidermis, endodermis and the
entire phloem areas of plants. Acid and alkaline phosphatases are associated with fungal
haustorial contact with the host vascular system, indicating their connection with those
physiological and biochemical activities concerned with the exchange of materials between
host and parasite. Histochemical observations were therefore carried out to ascertain whether
disruption of cells occurred as a symptom of soft rot disease of yam tubers caused by the
fungus, Botryodiplodia theobromae. Localizations of these enzymes in the host-parasite
union gave an insight into the distribution of such enzymes.
Peroxidase was detected by brown coloration in xylem and phloem cells of the healthy cells
(Figure 1a) which was more intense in the diseased section (Figure 1b). Sites of cytochrome
oxidase activity were recognized by a bright blue coloration more pronounced in the
conducting vessels of the diseased sections (Figure 1c) than in the healthy (Figure 1d). Acid
phosphatase was detected in the vascular bundles and cytoplasm of both healthy and diseased
tissues (Figures 2a & b). Sites of activity appeared as black deposits of lead sulphide (PbS)
due to the metal salt technique used. Alkaline phosphatase activity was less intense in the
cytoplasm and vascular bundles of the healthy than the diseased tissues. Penetration of the
host cells by fungal hyphae resulted in the breakdown of cell walls and depletion of the starch
grains (Ugoji and Uduebo, 1986). Peroxidase activity increased with infection. This is
correlated with resistance to pathogens in plants. In certain pathogenic fungi, cytochrome
oxidase takes part in the respiration of the mycelium. The enzyme has been found in a
number of Phycomycetes, Ascomycetes, Basidiomycetes and Deuteromycetes of which
Botryodiplodia theobromae is a member. Acid phosphatase is indirectly linked with energy
transfer through the hydrolysis of suitable substrates like sugar phosphates. Alkaline
phosphatase is directly linked with energy transfer reactions by making available phosphate
groups from cellular substrates.
Figure 1. Yam tissue sections showing peroxidase locations (a) healthy tissue (b) diseased tissue.
Cytochrome oxidase locations in (c) diseased tissue (d) healthy tissue. (x 120)
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Figure 2: Acid phosphatase locations in (a) healthy tissue (b) diseased tissue
SPERMOSPHERE/RHIZOSPHERE STUDIES
An analogy to saprophytic competition can be seen in the old game of musical chairs in
which a number of people, dancing to music around a circle of too few chairs, compete for a
seat when the music stops. Any individual may, in the early stage of the game obtain a seat
merely by position and chance but, as the game progresses, the stronger, more agile players
dominate. Microbes which possess the necessary attributes for substrate colonization also
will win in the end over competition. Logically, the remaining dominant organisms would be
largely of the same species with identical or similar demands for resources. Applying this
principle to the dominant microorganisms in ecological niches of the rhizosphere and
rhizoplane of plants, there is occurrence of some inter-specific competition, the intensity of
which is determined by nutrient availability.
The efficiency of three fungicides: thiram, benlate (benomyl) and brestan in reducing the
incidence of pathogens on the seeds (spermosphere) of okra (Abelmoschus esculentus L.) was
investigated. Root exudates are one of the important factors that stimulate the colonization of
roots by soil microorganisms. They contribute significantly to the attraction and
establishment of rhizosphere fungi, root pathogens and soil bacteria. The growth rate of
microorganisms at each point in the soil is controlled by the concentration of soluble organic
substrate and its diffusion through soil. Fungicides play useful role in the fight against fungi
and are harmless to plants. There is variation in their rates of decomposition by soil microbes
and the period of potency depends upon the type of chemical used, the rate and method of
application and the condition of the environment. The main colonizers in the rhizosphere
were Aspergillus and Penicillium while the rhizoplane (root surface) had species of
Fusarium, Penicillium and Cladosporium. Population of fungi in the immediate vicinity of
the roots (rhizosphere) of the seedling was high (3 x 104 colonies/g air-dried soil) compared
to isolations from various distances from the primary root. Thiram caused an immediate
reduction in the number of fungi compared to benlate and brestan.
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Figure 3: Persistence of thiram in soil
The rate of disappearance of thiram from soil was also assessed. In the 5th week, it had
disappeared completely due to the action of microbes (Figure 3). Thiram at minimal
application rate of 100μg/g soil reduced fungal population by one-third compared to the other
two. This observation may be due to differences in the degree of toxicity, percentage active
ingredient, solubility in water and degradability to non-effective compounds by fungi before
seed germination. The presence of mycoflora on or in seeds may result in prolonged
dormancy, reduced emergence or vigor of the seedlings due to mycotoxins (Ugoji, 1993).
Effects of common pesticides used in Nigeria on soil microbial populations.
Owing to the ever increasing use of pesticides in Agriculture and public health, an
investigation was carried out to study their probable deleterious biological effects on soil
microbial populations. Eleven pesticides were investigated, out of which phenylmercury
acetate (Agrosan) at 50μg/g inhibited bacterial density the most, from 4,400,000cfu/g to
240cfu/g. Pentachloro nitrobenzene (PCNB) reduced bacteria population to 2,200cfu/g
whereas tetramethyl thiuram disulphide (thiram) suppressed bacterial population by 2 log
orders of magnitude. The application of 1-naphthylmethyl carbamate (Vetox 85) and
1,2,3,4,5,6–hexachlorocyclo hexane (Gammalin 20) also repressed the bacterial number by 2
log orders of magnitude. PCNB reduced the actinomycete density from 360,000 to 340cfu/g
and completely eliminated all fungal and protozoal propagules. The 1,2,3,4,5,6hexachlorocyclo hexane completely wiped out all the fungi whereas phenylmercury acetate
eliminated all the protozoa and reduced the fungal population from 34,000 to 80 colonies/g.
In general, protozoa and fungi were more susceptible to fungicides than bacteria and
actinomycetes (Table 1). The herbicides, 2,3,5,6-tetra chloroterephthalic acid (Dacthal), 4nitrophenyl-2-nitro-4-trifluoromethylphenyl ether (Preforan) and 2-ethyl-6-methyl-Nmethoxy-1-methyl ethyl-chloroacetanilide (Dual) were harmless (Odeyemi et al., 1988).
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Table 1: Microbial population of soil samples 3 days after treatment with various concentrations
of pesticides compared with that of untreated soil (mean data of 3 replicates)
Shelf-life/storage of Bacillus isolates on spermosphere of maize (Zea mays L.), bean
(Phaseolus vulgaris L.), lettuce (Lactuca sativus L.) and cucumber (Cucumis sativus L.)
over a 12-month period.
Public concerns with fungicide residues and pathogen resistance to some pesticides have
increased the need to find alternative methods for protection against crop diseases. The use
of environmentally friendly microorganisms has proved useful in plant growth and disease
control. A biological agent must possess, among other desirable characteristics, propagules
that must be viable with good shelf-life. Gram-positive bacteria like Bacillus have an
advantage over their Gram-negative counterparts due to the formation of endospores. The
various seeds were bacterized with approximately 9 log10 cfu/g, air-dried in a laminar flow
chamber and placed at ambient temperatures. Samples were removed monthly for assessment
of spermosphere bacteria. There was initial upward trend of bacterial populations from 1-5
months which stabilized between months 5 and 6. Populations decreased from months 7 - 12.
It is therefore advisable to withdraw bacterized seeds for planting in the 5th - 6th months of
storage (Ugoji et al., 2006).
(a)
(b)
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(c)
(d)
(e)
Figure 4. a. SEM of inoculated maize showing Bacillus (B81) cells (B) and Pelgel® (P).
b. Maize seed - stacked bar chart of mean values for log10 CFU/g vs. time in
months showing standard error bars of the mean at 2.5%
c. Bean seed - stacked bar chart of mean values for log10 CFU/g vs. time in
months showing standard error bars of the mean at 2.5%
d. Cucumber seed - stacked bar chart of mean values for log10 CFU/g vs. time
in months showing standard error bars of the mean at 2.5%
e. Lettuce seed - stacked bar chart of mean values for log10 CFU/g vs. time in
months showing standard error bars of the mean at 2.5%
Colonization of Bacillus sp. on seeds and in plant rhizoplane
Seed coating, dipping and Scanning Electron Microscopy (SEM) methods were employed to
study bacterial and fungal colonization of the seeds and seedlings of maize (Zea mays L.).
The bacterial colonization on the seeds was 90%. When the coated seeds germinated,
bacteria, moved to the emerging radicle. The results indicate that attachment to the seed coat
and the rhizoplane by Plant Growth-Promoting Rhizobacteria (PGPR) is an important factor
in the successful colonization of the rhizoplane. To test the biocontrol nature of Bacillus,
bacterized seedlings were placed in Petri dishes inoculated with Rhizoctonia solani, a fungal
pathogen. The fungal hyphae were colonized by the bacterial cells which caused disruption
of the hyphae which then prevented them from colonizing the roots and causing any damage.
Bacillus can therefore be used as a PGPR and as a biocontrol agent (Ugoji et al., 2005).
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(a)
(b)
(c)
(d)
(e)
Figure 5. a. SEM of root tissue of maize seedlings grown after inoculation with Bacillus cells
(B) and seed coat adhesive (P).
b. SEM of root tissue of maize seedlings grown after inoculation with Bacillus (B)
c. SEM of maize root seedling showing abundant Bacillus cells on the roots
d. SEM of maize root seedling showing hyphae of R. solani (H) and Bacillus (BC)
e. SEM of inoculated maize root seedling showing disrupted R. solani hyphae (H)
unable to penetrate the root tissues
Studies on organisms associated with Kargasok tea production.
Kargasok tea is an alcoholic beverage that originated from Kargasok, Russia and the
organism used for its fermentation is “Kargasok yeast”. Previous unscientific reports claimed
that the beverage is rich in nutrients and that it is a remedy for many kinds of ailments such
as hypertension, arthritis, insomnia, obesity, cancer, infertility and coronary diseases. The
“yeast” was used to ferment boiled water extract of Lipton tea (Thea assamica) to which
sugar (Saccharum afficinarum) was added. The consumption of the beverage without
pasteurization made it important to investigate the nature of the organisms associated with it
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and suggest ways to improve the quality. Eleven genera of bacteria were isolated in the
fermentation broth, both pathogenic and non-pathogenic. Listeria monocytogenes, Bacillus
spp., Salmonella spp., Staphylococcus spp., and Proteus are pathogens. The unpasteurized
beverage is therefore not safe for consumption (Nwachukwu and Ugoji, 1993).
Effect of Heavy metal pollution on soil microbial activity.
Several reports indicate that heavy metals interfere with the biochemistry of diverse groups of
microorganisms isolated from their natural environments (Utgikar et al., 2004; Sani et al.,
2003). However, information relating to the sensitivity of whole soil bacterial community to
heavy metals is not much. Microorganisms do not live in isolation but in complex biological
communities within which exist complex interactions arising from biotic and abiotic
influences. The effects of heavy metals on soil microbial processes were therefore
investigated over a period of 6 weeks, using sulphate salts of Copper, Zinc and Nickel. The
parameters measured were microbial mineralization of Carbon and Nitrogen, microbial
Carbon and respiration. By the 6th week post treatment, the rates of C accumulation were
high in the Cu (6.03%) and Cu:Zn (5.80%) treatments, but low in Ni and Zn, 4.93% and
5.02% respectively. The rates of N mineralization were 0.41 and 0.44% in samples treated
with Cu and Cu:Zn compared to 0.22% and 0.24% at the onset of the experiments. Soil
microbial biomass declined from 183.7μg/g and 185.6μg/g before treatment to 100.8μg/g and
124.6μg/g in samples treated with Cu:Zn and Cu respectively. The rate of respiration of the
soil microbial populations was also inhibited by the metals, from an average rate of 2.51 2.56μg of C/g to 0.98, 1.08 and 1.61μg of C/g in the Cu:Zn, Cu and Zn-treated soils at the
end of the experimental period (Nwuche and Ugoji, 2010).
For ecotoxicological research to be able to influence policies and regulations pertaining to
environmental sustainability and conservation, it must be methodologically planned and
ecosystem-oriented. This is because the existence of bacterial species that are tolerant to a
pollutant is not indicative of the effect of selective pressure due to that pollutant on other
species. Heavy metals come from a variety of sources but principally anthropogenic
activities such as chemical manufacturing, electrical power generation, coal and ore mining,
smelting and metal refining, metal plating and to some extent, domestic sewage (Gazso,
2001). Some of the metals such as Cu, Ni and Zn are essential in very low concentrations,
serving as components of enzymes, structural proteins, and pigments and in maintaining the
ionic balance of cells (Kosolapov et al., 2004). There was apparent toxicity experienced by
the soil microbes. Only the Cu and Cu:Zn treatments had significant (P<0.5) effects on the
biochemical processes (Nwuche and Ugoji, 2008).
Fermented Cereal gruel “Ogi”.
Cereal-based foods are a major source of inexpensive dietary energy and nutrients in
developing countries. They are processed mainly through fermentation. The common
fermentation bacteria are species of Leuconostoc, Lactobacillus, Streptobacillus,
Pediococcus, Micrococcus and Bacillus. “Ogi” is prepared by bacterial fermentation of
cereals like maize (Zea mays L.) and Sorghum bicolor L. which provide calories, nutrients
and probiotic factors in human diets. In this study, indices of nutrition, palatability, etc. using
Lactobacillus pentosus and L. acidophilus as starter cultures were assessed in the fermented
gruel. The biochemical analyses showed that the concentrations of acid, acetoin and diacetyl
increased in comparison to the controls indicating improved organoleptic properties. There
were also increased levels of reducing sugars, proteins and amino acids. Lysine, isoleucine
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and arginine were elicited in all the fermented samples indicating desirable nutritional status.
The mixed culture fermented samples had higher values than the single culture fermented
samples for all parameters tested indicating higher efficiency. Although the spontaneous
process involving chance inoculation by natural microflora is the cheapest method, its
contamination is a major cause of diarrhoeal diseases and associated malnutrition especially
in children. This traditional weaning infant food can be biologically improved into an
acceptable protein - rich food that will reduce significant protein deficiency associated with
infantile diarrhoea in our environment (Opere et al., 2012).
The starter cultures had earlier been used as probiotics in the control of shigellosis, a common
form of diarrhoea in children in developing countries. Experimental and control mice were
fed with cooked “ogi” and later challenged orally with Shigella dysenteriae using sterile
catheters. They received a double challenge of 2 x 106 cells/ml in peptone water. They were
observed daily for symptoms of diarrhoea, change in stool texture and the number of
survivors, for a period of 20 days. The percentage of survivors was calculated. Opere et al.
(2003) had earlier suggested the use of starter cultures in the preparation of weaning foods,
for the control and prevention of incidences of shigellosis in human environments.
Solar disinfection of water
The problems posed by water and water-borne diseases especially in rural communities of
developing world spurred us to look into the use of solar energy for disinfection of water.
Nigeria lies between latitudes 4 o and 14o N and has a good solar climate with an annual
global average on horizontal surface varying from 3.7 kwh/m2 day along the coastal areas to
about 7.0 kwh/m2 day in the semi-arid areas of the country (Chendo and Lodan, 1993).
Bacteriologically contaminated waters were collected from various sources in the Lagos
metropolis and irradiated using liquid filters made from copper nitrate dihydrate (CuNO3)2.
2H2O) in the beam-splitting technique, to extract the ultraviolet (UV) portion of the solar
spectrum. After 5h, the total bacterial load was reduced. Coliform bacterial population had
percentage kill between 98.12 – 99.52%. Bacterial isolates from the control samples include
Serratia sp., Acinetobacter sp., Pseudomonas sp., Bacillus spp., Enterobacter sp.,
Flavobacterium sp. and Escherichia sp. After 5h irradiation, only Pseudomonas sp. and
Bacillus spp. were isolated (Chendo and Ugoji, 1994).
HEALTH AND ENVIRONMENT
The antibacterial activities of aqueous extracts of ten African chewing sticks on oral
pathogens were investigated. Aerobic and anaerobic bacteria isolated from dento-alveolar
abscesses, periodontal infections and gingivitis and reference bacterial strains were used as
test microorganisms. The barks and pulp of the chewing sticks were chopped, sun-dried and
milled. Each extract was made by adding 90ml of sterile deionized distilled water to 10g of
the resultant fibres. The mixture was heated in a Soxhlet extractor before transferring to a
rotary evaporator. Each thick paste was then diluted and tested for its activity. The aerobic
organisms were Streptomyces pyogenes, viridans streptococci, Staphylococcus aureus,
coagulase –ve staphylococci, Klebsiella pneumoniae and Pseudomonas aeruginosa. The
anaerobic flora were Peptostreptococcus sp. Porphyromonas gingivalis, P. melaninogenica
and Bacteroides oralis. All the plants tested displayed antibacterial activities. Pseudocedrela
kotschyi, Ocimum gratissimum, Garcinia kola, Anogiessus symperii and Serindeia warnecki
exhibited broad spectrum antibiotic activities but their efficiencies differed, depending on the
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test bacteria strains. Vernonia amygdalina, Massularia acuminata and Jatropha curcas
demonstrated high but selective activity against the anaerobes. Phoenix reclinata showed
consistently moderate activities against the aerobic and anaerobic pathogens. Fagara
xanthoxyloides showed moderate antibacterial activity against both the aerobic and anaerobic
pathogens. The broad spectrum antibiotic activities exhibited by Pseudocedrela kotschyi,
Ocimum gratissimum, Garcinia kola, Anogiessus symperii and Serindeia warneckei make
them suitable for the maintenance of good oral health. The study has shown the presence of
antibacterial substances in all the chewing sticks evaluated (Ugoji et al., 2000).
Table 2: African chewing sticks and their local names
BOTANICAL NAME
Pseudocedrela kotschyi
Ocimum gratissimum
Garcinia kola
Vernonia amygdalina
Massularia acuminata
Jatropha curcas
Phoenix reclinata
Fagara zanthoxyloides
LOCAL NAME
Emi-gbegiri
Efinrin nla
Orogbo
Ewuro jije
Pako Ijebu, orin
Ijebu
Lapalapa, Botuje
Ekikun, Olokun
Ata
Honey
Honeys together with olive oil appear in the list of products that describe the abundance of
good things in the land of Palestine. The land is referred to many times in the bible as the
land that flows with honey (Deut. 8:8-10, 11:9, 27:3, Ex. 3:17, 13:5, 33:3, Lev. 20:24, Num.
13:27, 16:13, Josh. 5:6, Jer. 11:5). Oil and honey are mentioned in Ezek. 16:13 &19, 27:17, 2
Kings 18:32, Deut. 32:13, Jer. 41:18. Samson ate honey he found in the carcass of the lion he
had earlier killed with his bare hands (Judges 14:5-10). It is from this we got that beautiful
riddle:
“Out of the eater came what is eaten
and out of the strong came what is sweet” with the answer
“What is sweeter than honey
and what is stronger than lion?”
From the Koran, Surah 16:68-69
68 And thy Lord inspired the bee, saying: Choose thou habitations in the hills and in
The trees and in that which they thatch,
69 Then eat of all the fruits, and follow the ways of
The Lord made smooth for thee, There cometh forth from their bellies a drink
Of diverse hues wherein is indeed a healing for people who reflect.
There was therefore the need to investigate this wonderful product. The antibacterial effect of
local honey on bacterial agents of diarrhoea was determined in-vitro by the impregnation of
filter paper discs in diluted and undiluted samples. Honey is the nectar and saccharine
exudation of plants, gathered, modified and stored as honey in the comb by honey bees (Apis
mellifera). Bacterial strains used were Escherichia coli, Shigella boydii, Salmonella typhi,
Vibrio cholerae, Aeromonas hydrophilia, Plesiomonas shigelloides, Yersinia enterocolitica
and Campylobacter jejuni (Table 3). Honey destroys bacteria because of its high sugar
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content which causes shrinkage and because of the presence of an inhibitory substance called
inhibin (Obi et al., 1994).
Table 3: Inhibition of growth of enteropathogens tested by the disk method using undiluted
honey and varying concentrations of honey on all media
Predisposing and bacteriological features of otitis media
Otitis media is an inflammation of the middle ear that is more frequent in children. The study
aimed at determining the predisposing factors and the bacterial etiology. Children less than 5
years presented with highest infection rate. Incidence was higher in the rainy season (May October) than in the dry season (November - April). Identified predisposing factors were age
(19.8%), upper respiratory tract infection (14.8%), poor hygiene and unorthodox practices
(14.8%), adenoid inflammation 8.5% and trauma (6.1%) (Table 4) (Nwokoye et al., 2012).
Age was considered a risk factor because eustachian tubes of children (<5yrs) are shorter and
more horizontally positioned than those of adults. Since cold weather predisposes children to
upper respiratory infections, most cases are seen in the rainy season. Based on this
observation, Physicians may consider a more aggressive approach of treatment and
management of otitis media during the wet months.
14
Table 4: Distribution of isolates in otitis media
Evaluation of the antimicrobial properties of unripe banana (Musa sapientum, L., lemon
grass (Cymbopogon citrates) and turmeric (Curcuma longa L.) on pathogens.
The clinical isolates used include aerobic facultative bacteria – Staphylococcus aureus
ATCC 259212, Salmonella paratyphi, Shigella flexneri, Escherichia coli ATCC 25922, E.
coli, Klebsiella pneumoniae, Bacillus subtilis and Pseudomonas aeruginosa. All the Grampositive bacteria (S. aureus, S. aureus ATCC 25921 and B. subtilis) and all the Gramnegative bacteria E. coli, E. coli ATCC 25922, Ps. aeruginosa, S. paratyphi, S. flexneri and
K. pneumoniae were susceptible to ethanolic extracts of the test plants while E. coli ATCC
25922, E. coli, Ps. aeruginosa and S. flexneri were not susceptible to the aqueous extracts of
the medicinal plants. Ethanolic extracts showed greater antimicrobial activity than the
aqueous extracts. The killing rates of the extracts varied. Unripe banana had less than 2h
killing time for S. aureus ATCC 25921, turmeric less than 3h for E. coli while lemon grass
had more than 3h for S. paratyphi (Figure 6) (Fagbemi et al., 2009).
15
(a)
(b)
Figure 6. a. Minimum inhibitory concentration (MIC) of isolates to tumeric (aqueous extract).
b. Minimum bacterial concentration (MBC) of isolates to tumeric (ethanolic extract)
In this study, the microbiological investigation has shown activities coherent to the use of
these plants in folk medicine. This implies that there is still a lot to gain from these medicinal
plants as an antimicrobial pointer to new sources of novel drugs.
WASTE AND ENVIRONMENT
Production of biogas from starchy wastes
Biogas is a renewable fuel provided by anaerobic digestion of organic materials as substrate
for biomethanation. The gas obtained through the action of methanogenic bacteria in the
absence of oxygen is flammable. Wastes generated during food preparation and consumption
as well as industrial, farming and market operations constitute enhanced risk of pollution to
the environment. This work reports on the comparative studies and effectiveness of spoilt
yam and cassava using abattoir effluent as the inoculum to produce biogas. This would
provide relatively cheap and reliable fuel source for human consumption. The process would
16
also reduce global warming which arises from major primary pollutants produced by human
activities.
The batch-type digester consisted of a stainless steel container and covered by welding so that
there is no access to air. A stirrer made of iron rod was attached through the upper in-let to
agitate the slurry at intervals. The gas holder was provided with a gas tap through which the
gas was led from a delivery pipe to a household gas cooker. The digester was fabricated
courtesy, Department of Physics, University of Lagos. Cassava substrate gave the highest
daily average of 397ml of gas, followed by a mixture of cassava and effluent, 310.4ml;
mixture of cassava, yam, effluent 259ml; mixture of cassava, yam 243.6m; yam 238ml;
mixture of yam and effluent 169.4 while the abattoir effluent produced 144.4ml (Bolarinwa
and Ugoji, 2010).
Anaerobic digestion of palm oil mill effluent and its utilization as fertilizer for
environmental protection.
Biodegradation of palm oil mill effluent to environmentally acceptable products was carried
out. This method of digestion was chosen in relation to efficiency of Chemical Oxygen
Demand (COD) and Biological Oxygen Demand (BOD) removal. Palm Oil Mill Effluent
(POME) wastes are the fibre-free, non-oil components obtained from the clarification zone of
oil mills. POME consists of various suspended components including cell walls, organelles,
and a spectrum of carbohydrates ranging from hemicelluloses to simple sugars, a range of
nitrogenous compounds from proteins to amino acids, free organic acids and an assembly of
minor organic and mineral constituents. In general appearance, POME sludge is viscous,
brown or grey. There is need to prevent environmental pollution due to large scale farming
action in Nigeria with particular reference to palm oil mill effluent. The study reports on the
microbial community involved in the degradation of palm wastes. The study serves as a
useful index of environmental pollution. The average total bacterial count was 1.3 x 106
cfu/ml while coliforms were 1.0 x 104 cfu/ml. Fungal population was 1.0 x 103 colonies/ml.
The two groups of bacteria isolated were the acid-formers and the methane-formers. The
former group includes Clostridium sp., Bacillus subtilis, Escherichia coli, Pseudomonas sp.,
Flavobacterium sp., Desulfovibrio sp. and Micrococcus sp. The methane-formers were
Methanococcus sp. and Methanobacterium. Fungal isolates include Fusarium moniliforme,
Geotrichum candidum, Cunninghamella echinulata, Botryodiplodia theobromae, Penicillium
sp., Aspergillus sp. and Trichoderma viride. The final products were methane and carbon
dioxide, with a rich, odourless fertilizer. The actual digestion of concentrated POME,
requires only about 10 days with a removal efficiency of 93-97% (Table 5) (Ugoji, 1997).
Table 5: Performance of anaerobic digester
17
Effect of waste engine oil spillage on soil physico-chemical and microbiological
properties.
Changes in the physico-chemical and microbiological properties of soils contaminated with
waste motor oil were monitored over a 24-week period. There was an initial decrease in
microbial counts followed by a subsequent increase in population levels after 4 weeks.
Microbial species diversity was however, reduced in oil-contaminated sites relative to the
control sites. Hydrocarbon-utilizing bacteria from the experimental sites were identified as
Pseudomonas, Acinetobacter, Alcaligenes, Flavobacterium and Corynebacterium. They all
grew on long-chain n-alkanes, crude oil and fresh engine oil. Laboratory biodegradation
studies of fresh engine oil using strains of Pseudomonas, Acinetobacter and Corynebacterium
showed a progressive decrease in oil concentration and pH of the medium due to the
production of acidic metabolites (Amund et al., 1993). Pseudomonas species were found in
large numbers at the experimental site. The pseudomonads are the normal flora of the soil
which are known to degrade a wide variety of hydrocarbons. Other hydrocarbon-utilizing
species with similar nutritional versatility are Acinetobacter, Alcaligenes and
Corynebacterium, thereby lending credence to the existence of natural self-rehabilitation
processes in oil-polluted soils, albeit very slow.
Impacts of Crude Petroleum Spills on Microbial Communities of Tropical Soils.
The impacts of pollution of soil by crude petroleum and its effects on microbial populations
were investigated, 12 months after an oil spill in Eleme, Rivers State, Nigeria. An arm of
pipeline carrying crude petroleum into the major Borri-Eleme pipeline got fractured. The
fractured spot was designated “epicentre”. The spillage covered an area of about 10km
radius from the “epicentre” which flowed into the nearby creeks and rivers (Figure 7).
18
Figure 7. Photo of heavily polluted swamp due to ruptured pipeline
Apart from forming breeding centres for mosquitoes, the causative agents of many tropical
diseases such as malaria, many economic plants were observed to be destroyed. The spillage
had adverse impacts on the soil ecosystem causing drastic changes in the microbial
community, temperature regimes and pH levels. It was observed that the recovery of the
disturbed soil was still incomplete 12 months after the spillage. The protracted persistence of
the crude petroleum deposit could be due partly to the huge quantity of oil spilled and also to
the fact that hydrocarbon-utilizers such as Methanobacterium sp. and Methanosarcina sp.
were present in low numbers (
(Table 6) even though heterotrophic microorganisms
such as Bacillus sp., Pseudomonas sp. Aspergillus sp., and Candida sp., also degrade crude
oil (Nwachukwu and Ugoji, 1995; Amund and Igiri, 1990).
19
Table 6: Population densities (CFU g-1 soil ± SE) of microorganisms in soils polluted with
crude petroleum and in undisturbed soils
The greater number of total hydrocarbon-utilizers in the disturbed sites indicates that the
crude petroleum attracted and stimulated faster multiplication of hydrocarbon-utilizers than
what obtained in the undisturbed soils. Crude oil contains carcinogenic compounds such as
polycyclic aromatic compounds. It is essential that oil industries take adequate measures to
forestall pollution of the environment. Flow pipes for transportation should be periodically
checked and weak, leaky ones, replaced. They should have functional devices such as straws
for skimming and absorbing oils once there is any spillage, in addition to the use of chemical
dispersants.
Biological Treatment of Textile Industrial Effluents in Lagos Metropolis, Nigeria.
Synthetic dyes are used in many industries such as textile, paper, printing, colour
photography, food processing, etc., and as additives in petroleum production. Over 10,000
dyes with an annual production of over 7 x 105 metric tonnes are commercially available
worldwide and 5-10% of the dyestuff is lost in the effluent. Colour is usually the first
parameter to be recognized in wastewaters and affects the aesthetics, transparency and gas
solubility of water bodies. The effluent derived from textile and dyestuff activities provokes
a very serious environmental impact in neighbouring water bodies mainly because of its
toxicity and carcinogenicity. The objective of this study was therefore to investigate the level
of pollution caused by textile effluent and to evaluate the ability of naturally-occurring
bacteria to degrade the organic matter present in the effluent before discharge into natural
water bodies. A summary of the physico-chemical characteristics of the wastewater and
Federal Environmental Protection Agency (FEPA) standards is presented.
Table 7: Physico-chemical characteristics of wastewaters (SD ± values)
20
The presence of high concentrations of these metals in the wastewaters is injurious to human
health if disposed without adequate treatment into the environment. The microorganisms
found to degrade the wastewaters include: Micrococcus sp., Enterobacter sp., Alcaligenes
sp., Bacillus sp. and Acinetobacter sp. (Ugoji and Aboaba, 2004). These microorganisms
were able to lower the Biological Oxygen Demand (BOD) to a very low level (4-10mg/l)
with Acinetobacter sp. and Bacillus sp. reducing the BOD to zero. These findings can serve
as an important contribution towards an economic and simple biological method of treating
textile industry wastewaters using microorganisms. These microorganisms are naturally
occurring in wastewaters and so can readily be isolated. This strategy will also contribute to
effluent mineralization efficiency.
BIOREMEDIATION
Bioremediation is the use of microbe metabolism to remove pollutants. Three primary
ingredients for bioremediation are: presence of a contaminant; an electron acceptor and the
presence of microorganisms that are capable of degrading the specific contaminant.
Microorganisms that live in the soil help plants to absorb more nutrients. Plants and these
silent, sleepy, friendly microbes are involved in nutrient recycling. The microbes help the
plants to “take up” essential energy sources. In return, plants donate their waste by-products
for the microbes to use for food. Scientists use these friendly microorganisms to develop
biofertilizers. With a large population of the friendly bacteria on the roots of leguminous
plants, they can use naturally – occurring nitrogen instead of the expensive traditional
nitrogen fertilizers. Biofertilizers help plants use all the food available in the soil and air, thus
allowing farmers to reduce the amount of chemical fertilizers they use. This helps preserve
the environment for generations to come.
Bioremediation of a crude oil-polluted site in the Niger Delta using Zea mays L.
The study highlights the use of a combination of natural attenuation and a plant to carry out
phytoremediation of crude oil-polluted soil. Bacterized Zea mays L. (maize) seeds were used.
Seed germination, plant growth and crude oil concentrations were monitored. The
hydrocarbon content of the crude oil reduced from 146,000ppm to 5,148ppm and from
151,000ppm to 5,100ppm in the control and treated sites. In the control site, crude oil
concentration reduced from 5,500ppm to 548.56ppm for total petroleum hydrocarbon (TPH),
1.6ppm to 0.005ppm for benzene, toluene, ethylene and xylene (BTEX) and 25.02ppm to
0.03ppm for Polyaromatic hydrocarbons (PAHs) respectively while for the treated site,
reductions were from 5,500ppm to 374.04ppm, 1.6ppm to 0.001ppm and 25.02ppm to
0.005ppm. After 36 days, the average fresh root biomass of the treated seedlings was 12.5g
while it was 5.3g in the control treatment. This suggests a high potential of Pseudomonas
aeruginosa as a Plant Growth-Promoting Rhizobacterium (PGPR).
The Potential use of Domestic Wastewater in Bioremediation of Crude-Oil Polluted
Soils.
The investigation was carried out to assess the level of bioremediation of the crude-oil
polluted soil using wastewater. Economic crops are used to assess the ability of the
bioremediated soil to support growth. Wastewater from a fast food outlet was used as the
21
source of inoculum. The soil samples were polluted with 1- 4% crude oil. Two days after, the
wastewater was added to each batch. Controls had only tap water. These were added biweekly for 20 weeks before the test seeds of maize (Zea mays L.) and bean (Phaseolus
vulgaris L.) were planted. Both seeds germinated on the 5th day. However, stunted growth
of maize and bean seedlings were observed in soil polluted with 1% crude oil while chlorosis
was observed by the 10th day in the soils with higher concentrations of the crude oil. By the
13th day, leaf droppings were observed for both crops in the polluted soils. In the soils
remediated with the wastewaters, the residual oil concentration was slightly lower at 5% level
of significance. The seedlings did better in the polluted soils remediated with the wastewater
than in the controls. The Energy Dispersive X-ray (EDX) microanalysis of the soil samples
showed that silicon was the most abundant mineral component in the garden soil apart from
carbon, oxygen, aluminium, potassium, titanium and iron (Figure 8).
(a)
(b)
(c)
Figure 8. EDX microanalysis of a. Garden soil
b. Garden soil and wastewater
c. Garden soil and 2% crude oil
PLANT GROWTH-PROMOTING RHIZOBACTERIA (PGPR)
This group of bacteria that colonize roots or rhizosphere soil and beneficial to crops are
referred to as plant growth-promoting rhizobacteria (PGPR). Species of Pseudomonas and
Bacillus can produce some phytohormones or growth regulators that cause crops to have
greater amounts of fine roots which have the effect of increasing the absorptive surface of
plant roots for uptake of water and nutrients. These PGPR are referred to as biostimulants.
22
THE USE OF SOIL MICROBES AS BIOFERTILIZERS AND FOR
BIOREMEDIATION
There is a lot of debate on the overuse of chemical herbicides, pesticides and fertilizers. They
become an environmental hazard because they undergo degradation by microbes and
ultraviolet light which releases toxic chemicals into the environment. Trials are going on to
use the genetically engineered live soil bacteria for coating seeds before planting.
Biofertilizers are being used in place of chemical fertilizers to further reduce the
environmental hazards due to chemical fertilizers. They are preparations containing living
cells or latent cells of efficient strains of microbes that help crop plants’ uptake of nutrients
by their interactions in the rhizosphere when applied through seed or soil. They accelerate
certain microbial processes in the soil which augment the extent of availability of nutrients in
a form easily assimilated by the plants.
Evaluating Pseudomonas aeruginosa as Plant Growth-Promoting Rhizobacteria
(PGPR).
Limited agricultural land, soil pollution, environmental degradation and crop diseases are
among the many factors hindering agriculture in the modern day. These have brought about
the challenge to develop new methods of improvement in crop yield and disease control. The
usual chemical methods of improving plant growth and disease control have environmental
pollution effects. Environmentally friendly microorganisms have proved useful in plant
growth promotion, disease control and pest management. This study therefore focused on the
effectiveness of PGPR using three test crops Abelmoschus esculentus L. (okra), Lycopersicon
esculentum L. (tomato) and African spinach. It also determined whether the method of seed
inoculation has any impact on the effectiveness of the PGPR. The effect of the PGPR was
compared to that of fertilizer, NPK, because the ultimate aim of fertilizer application to any
crop plant is to improve its overall growth performance and consequently its yield (Figure 9).
Figure 9. Dry biomass of plants at 65 days of growth
BS: plants from seeds bacterized by soaking; BC: plants from seeds bacterized by
coating. WF: plants from seeds soaked in distilled water plus NPK fertilizer
application; DW: plants from seeds soaked in distilled water only (control).
23
In this study, there was a clear improvement in growth after NPK fertilizer application
compared to the controls. However, PGPR performed better. Pseudomonas aeruginosa has
proved suitable as PGPR which further strengthens its usefulness both in the environment and
agriculture (Adesemoye and Ugoji, 2009; Adesemoye et al., 2008).
Rhizotron Studies on Zea mays L. to Evaluate Biocontrol Activity of Bacillus subtilis.
Present practices for plant disease control are based largely on genetic resistance in the host
plant, management of the plant and its environment and synthetic pesticides. Different
strains of PGPR can exert various effects on plants including biological control of soil-borne
pathogens like Rhizoctonia solani, Pythium sp. and Fusarium sp. They attack the young
emerging plants. Fungicide and chemical seed treatments disrupt the chemical equilibrium
within living microbial community but PGPR and bioprotecting rhizobacteria (PGPBR) can
overcome this problem. This work was aimed at using Bacillus subtilis as a biocontrol of R.
solani, Pythium sp. and Fusarium sp. using maize seedlings. Maize (Zea mays L.) seeds were
bacterized and grown in Perspex boxes (rhizotrons) fabricated by the main author. They were
20mm thick, 20mm wide and 200mm deep. Germination occurred but the seedlings were
later attacked by R. solani just below the soil level. The hypocotyls rotted and the plants fell
over (Figures 10 and 11) (Ugoji and Laing, 2008).
Figure 10 a. SEM of maize seed coat showing Bacillus subtilis cells.
b. Effect of Bacillus subtilis B77 and B81 on control of Rhizoctonia solani (RH)
R-maize root, ST- seed treatment
24
(a)
(b)
Figure 11. The beneficial effects of Bacillus subtilis B77 on the damping-off
caused by Pythium sp. on maize roots. (a) Bacillus B77 + Pythium sp. (b).
Pythium sp. only.
ONGOING RESEARCH
Contributions from Kareem et al. (2013).
The effect of a plant growth-promoting fungus as biofertilizer and biocontrol agent
Trichoderma longibrachiatum was assessed as a biofertilizer and a biocontrol agent of a
pathogenic fungus, Fusarium oxysporum in the screenhouse by evaluating its effects on the
biomass, growth and yield of cucumber and lettuce propagated through tissue culture
techniques on Murashighe and Skoog medium. The results of the biofertilizer experiment
showed that the growth parameters such as plant heights, number of leaves and the leaf areas
of the T. longibrachiatum-treated plants were higher than those of the NPK-fertilized plants
while those of the NPK-fertilized plants were higher than the control plants. The mean plant
heights of cucumber ranged from 14.17cm to 19.67cm while those of leaf areas ranged
between 100.49cm2 to 141.34cm2. The biomass of the whole plant of lettuce revealed that the
highest values of 37.13g and 0.95g were recorded for the fresh and dry weights respectively.
The number of fruits, the fruit diameters and fruit lengths indicated that better yields were
obtained from the T. longibrachiatum-inoculated plants than the NPK-fertilized plants and
the control plants. The results of the biocontrol effect of T. longibrachiatum against F.
oxysporum showed that T. longibrachiatum was able to control F. oxysporum both in-vitro
and in-vivo. The growth and yield of the plants inoculated with T. longibrachiatum were
better than those of the control plants inoculated with F. oxysporum only.
25
A
C
B
D
Plate 1. Fruits of cucumber
A= NPK fertilized fruit
B=Fruit from seedlings in 3cm deep hole with Trichoderma put 3cm below the seedlings
C= Fruit from seedlings in 3cm deep hole with Trichoderma put 3cm below the seedlings
and in another 3cm hole on one side of the seedlings
D= Fruit from seedlings in 3cm deep hole with Trichoderma placed in hole 3cm below and
3cm on both sides of the seedlings
Contributions from Obasi et al. (2013).
Effluent as reservoirs of antibiotic resistance genes using selected antibiotics as study
targets
Wastewaters were collected from several pharmaceutical industries with a view to isolating
microorganisms with resistance genes from environmental samples.
Antibiotic susceptibility: Gram-negative enterobacteria and a few non-fermenters were
subjected to 28 antibiotics using the VITEK 2 automated method for detecting the
resistogram of bacteria such as the Minimum inhibitory concentration (MIC), Extended
spectrum β-lactamase (ESBL) and multiresistant Gram-negative (MRGN) of the bacterial
strains. The bacteria isolates were identified using VITEK 2 automated machine, Polymerase
chain reaction (PCR) and sequencing by Analytical profile index (API). One hundred and ten
strains of Gram-negative bacteria isolates made up of the enterobacteria such as Klebsiella
pneumoniae harboured ESBL gene (CTX-M-15 SHV, TEM), Enterobacteria cloacae,
Serratia marcesens, Providencia stuartii were all resistant to Ampicillin and Proteus
mirabilis was resistant to Ticaracillin. The non-fermenter strains such as Pseudomonas
aeruginosa, Burkholderia cepacia, Burkholderia cenocepaci and Stenotrophomonas
maltophilia were resistant to Cephalosporins and Fluoroquinolones.
26
WALKING HOME / DRIVING HOME MESSAGES
1.
Our survival as a nation, State, corporate entity, institution and individuals is
dependent on how well we take care of our environmental resources and their
protection depend on changed behaviour by all individuals, household, consumers,
private as well as public institutions. Efforts to conserve and protect global diversity
should be seen as a task that must be carried out for posterity and sustainability.
2.
There should be political will of Government to enforce protocols and legislations on
the environment. Stakeholders must be mobilized and there should be collaboration
between the public and private sectors. There should be structures and agencies to
enforce them.
3.
Environmental Impact Assessment (EIA) should be reinvigorated as a major
instrument for identifying likely environmental impacts and ensure that appropriate
mitigation measures are provided before major projects are implemented. A website
for EIA in Nigeria has been developed (www.ea-environment.org). This is to make all
EIA approved reports in all sectors available for reference, public awareness and
follow-ups.
4.
Nigeria’s high population generates large quantities of waste to the tune of 3.2
million tonnes annually and only 20-30% of it is collected. This has resulted in
blockage of drainages, flooding and poor air quality etc. The Federal Ministry of
Environment should be complimented for implementing integrated waste
management programmes across the country. Government has commissioned some
Pilot Plastic Recycling/compost-making plants.
5.
The production of biofuels-solid from straw, sawdust etc. Liquid from alcoholic
fermentation, gaseous (biogas) formed through anaerobic fermentation of liquid and
solid wastes from agricultural and animal production and by biomass gasification
should be encouraged. This is a method of reducing the importation and
consumption of fossil fuels. It will also reduce the carbon-dioxide emission to the
atmosphere by about 90%. It is for this reason of sustainability that renewable
technology such as solar and wind power is gradually gaining more prominence to
support the already established fossil fuels and reduce the global dependence on
these fuel sources; increasing and diversifying the energy mix.
6.
As inhabitants of the environment, we are faced with sustainability challenges on a
daily basis. Most frequently, the issue of climate change and release of pollutants in
the form of carbon-dioxide from vehicle exhaust-pipes. As a result, the use of public
transportation and car-pooling are more environmentally friendly options compared
to individuals driving their personal cars.
7.
Sustainability, I feel, is a concept that has to be embraced on a personal level first
before it could be implemented on a larger scale. Only after achieving this, could our
natural resources be thoughtfully exploited and not over-exploited to ensure that
future generations do not lack these resources.
8.
Energy Efficiency and Conservation is of paramount importance in energy concepts
and energy delivery. The Energy Commission of Nigeria decided to establish a centre
to cater solely for issues pertaining to it. It’s importance stems from the fact that the
27
practice of efficiency and conservation is the most economical and environmentally
benign way of “generating’ energy rather than producing it directly. The Federal
Government is commended for choosing the University of Lagos as its base for the
National Centre for Energy Efficiency and Conservation (NCEEC) domiciled in the
Faculty of Engineering.
28
ACKNOWLEDGEMENTS
Mr. Vice-Chancellor Sir, permit me to express my gratitude to God Almighty who has given
us this day through His divine grace and favour.
We individually and collectively look backwards, inwards with juicy reminiscences of those
who lit the flame, who stirred the waters of fame and achievements, who opened fountains
through which numberless microbes combine to make huge and visible organs of
achievements in our lives. I therefore regard it a debt that must be paid and indeed right now,
to reveal as much as possible those who had positive influences on my education and career.
They are angels who open gates, they are awesome creatures who direct the paths, and they
are also marvellous giants who protect along the path.
I am at a destination now, a Professor of Environmental Microbiology, at the University of
Lagos. Let me therefore begin by appreciating the Vice-Chancellor, Professor Rahman Ade
Bello under whose tenure I got the “Chair”. I owe a lot to Professor Babajide Alo (DVC
Academic and Research), Professor Duro Oni (DVC Management Services), and the entire
management team of the University of Lagos, for their love and encouragement. May God
bless you all.
My gratitude goes to my alma mater – the University of Ife, (OAU) Ile-Ife, where I was
nurtured and the University of Lagos where my career was capped. I am grateful to my
Supervisor at Postgraduate level, Professor (Mrs.) Agnes Uduebo under whose guidance; I
learnt the rudiments of research. My collaborators at the University of KwaZulu-Natal,
Republic of South Africa, Professor Mark Laing and Professor Charles Hunter for my Postdoctoral experience.
To those who saw to the creation of the Department of Microbiology, I say “Thank you” for
your foresight, doggedness and selflessness. I am greatly indebted to my Dean, Professor M.
O. Ilori and my former Head of Department, Professor S. C. U. Nwachukwu, who were
instrumental in making sure a “Chair” was available for me to “sit on”. May God shower His
infinite blessings on you. To the Head of Department, Professor I. A. Adeleye and entire
members, academic, technical and administrative, I appreciate you all. We are one big, happy
family – the “Micrococcus”. I also thank all members of the Faculty. I must say that I have
enjoyed being part of the Faculty of Science. God bless you all.
With great appreciation, I thank Professors Olukayode Amund, M. A. C. Chendo, S. A.
Adekola, A. W. A. Edwards, G. O. Williams, Olu Odeyemi, D. O. Kolawole, Professor &
Professor O. Mabadeje, Professor and Mrs. L. C. Obi and Dr. O. Ohiokpehai. I am also
grateful to Fr. (Professor) A. Akinwale, O. P., Fr. (Dr.) D. Oyeshola, O. P., Dr. B. Obisesan,
Mr. & Dr. (Mrs.) S. Igiri and Mr. J. U. Igbosuah, for their wonderful roles in my life. May
God replenish you bountifully.
Our dear Vice-Chancellors of blessed memory – Professors Jelili Omotola and Adetokunbo
Sofoluwe, may God grant you perfect peace. Our dearly beloved Professor (Mrs.) Moni
Taiwo, Dr. Adigun Ogunkanmi and Dr. Hansel Erhie, may your beautiful souls rest in peace.
I am grateful to all members of the University of Lagos Community that I have interacted
with, in various spheres of life on campus especially the Press, when we had sleepless nights
working to get Convocation brochures on schedule. Special thanks too for putting your talent
and heart to marry form and content, to come up with the beautiful cover that catches the
intent of this Inaugural lecture. Oh! What can I say of my dear Postgraduate and
29
Undergraduate students? I owe you an arm and a leg for my success, cheerfulness and
vibrancy. I know you have turned out to be accomplished men and women in the corporate
and academic worlds. It is an honour to teach over the years. I love you all!
To my happy family: Bro. Nkencho, Sis. Ndudi, Azubuike, Adaoyibo, Malechi, Ndidi and
Isioma with their spouses – Rose, Uncle Louis, Rosemary, Ndy, Nnamdi, Ewie and Fred, I
thank you from the bottom of my heart. Without your love I would not have been what I am
today. May God bless you abundantly and keep us as one united and happy family. To my
lovely children, Anwuli and the husband, Nnamdi and Febechukwu, you have always been
my confidants. I give God all the glory. I thank God and appreciate you for your good
behavior, understanding and success in your studies. I entrust you to the grace of God. To my
little Angel, Chinedum, sent from heaven! God bless and keep you. My beautiful nieces,
nephews and cousins, you know I love and appreciate you all. Thank you and God bless you.
To the entire Ibusa Community, I say “Igwe nu”! Ogbeowele, “Onowu nu”!
My dad of blessed memory, Sir Charles Megwai Ugoji, KSM and our dearly beloved Mum,
Lady Cecilia Onyejinduaka Ugoji, LSM, who clocked 85 years last January (seated in the
audience), I thank you both for our upbringing and the realization that education is paramount
to our well-being. May God keep him in His bossom. “Requiescat in pace”, dear big Daddy.
When I think of our mother, the first thing that comes to my mind is how clearly the
description “the strong, silent type” fits her. Mother is neither talkative nor timid, but quite an
easy-going woman.
To the Catholic family – the Clergy, the Religious especially the Dominicans – the Master of
the Order – Fr. (Dr.) Bruno Cadore O.P., the Socius, Fr. Gabriel Samba O.P., Most Rev. Fr.
(Dr.) Charles Ukwe O.P., Rev. Sr. Faustina Jimoh O.P., Rev. Sr. Christy Umeadi O.P., I say
thank you for your love and prayers. I thank, in a special way, His Grace, Dr. Augustine
Akubueze, the Archbishop of Benin Archdiocese, Most Rev. Dr. Michael Elue, Bishop of
Issele – Uku Diocese, (my home Diocese), Archbishop Emeritus, Most Rev. Dr. Kwesi
Sarpong (Kumasi Archdiocese), Fr. (Dr.) Dan Chiezey O.P., Fr. (Dr.) Martin Aitsebaomo
O.P. and Fr. (Dr.) Cletus Nwabuzo O.P. and all the other Brothers and Sisters too many to
mention. I thank the Pastor, Rev. Fr. Felix Onemheghie O. P., the Pastoral team, Priests and
the entire Parishioners of St. Dominic’s Catholic Church, Yaba as well as the Parish Priest of
Catholic Church of the Resurrection, Magodo, Rev. Fr. Mike Etekpo MSP and his assistant,
Rev. Fr. Paul Adekoya and the entire Parishioners for their love and prayers. I wish to thank
Frs. Thomas Kraut O. P., Anthony Amoako-Attah O. P., and the Ghana Catholic Mission in
Hamburg, Germany. I also thank all my friends and well-wishers too numerous to mention.
To my beloved Dominican Brothers and Sisters of blessed memory, especially, Frs. Visigh
Igba O. P., Jude Dawson-Amoah O. P., Fr. (Prof.) Joe Kenny, O. P., Bro. Vincent Akpala O.
P., Bro. Paul Keteh, O. P., Srs. Beatrice Ugwu O. P., Helen Ekwueme O. P. etc. I pray that
their souls and the souls of the faithful departed through the mercy of God rest in peace.
Amen.
For the past, I give thanks and praise to God. For the present, I continue to depend on His
guidance and direction and for the future, I entrust to His divine providence believing fully in
the words of our Holy Father, Pope Francis that “God is the only good that cannot
disappoint”. His grace has led me thus far. I am confident that it will lead me on.
Thank you all for being so gracious. May God see you safely to your various destinations.
THANK YOU ALL AND GOD BLESS
30
REFERENCES
Adesemoye, A. O. and Ugoji, E. O. (2009). Evaluating Pseudomonas aeruginosa as plant
growth promoting rhizobacteria in West Africa. Archives of Phytopathology and
Plant Protection 42(2): 188-200.
Adesemoye, A. O., Ugoji, E. O. and Obini, M. (2008). Comparative studies of plant growth
promotion with Pseudomonas aeruginosa and Bacillus subtilis in three vegetables in
Lagos, Nigeria. Brazilian Journal of Microbiology 39: 423-426.
Amund, O. O. and Igiri, C. O. (1990). Biodegradation of petroleum hydrocarbon under
tropical estuarine conditions. World Journal of Microbiology and Biotechnology 6:
255-262.
Amund, O. O., Adebowale, A. A. and Ugoji, E. O. (1993). Effects of waste engine oil
spillage on soil physico-chemical and microbiological properties. Journal of Scientific
Research and Development 1(1): 61-64.
Antunes, L. C. and Ferreira, R. B. (2009). Intercellular communication in bacteria. Critical
Reviews of Microbiology 35: 69-80.
Antunes, L. C., Ferreira, R. B., Buckner, M. M. and Finlay, B. B. (2010). Quorum sensing in
bacterial virulence. Microbiology 156: 2271-2282.
Asad, S. and Opal, S. M. (2008). Bench-to-bedside review: quorum sensing and the role of
cell-to-cell communication during invasive bacterial infection. Critical Care 12: 236245.
Bassler, B. L. and Losick, R. (2006). Bacterially speaking. Cell 125: 237-246.
Bolarinwa, O. A. and Ugoji, E. O. (2010). Production of biogas from starchy wastes. Journal
of Scientific Research and Development 12: 34-45.
Caldwell, D. E. and Costerton, J. W. (1995). Microbial biofilms. Annual Reviews
Microbiology 49: 711-745.
Chendo, M. A. C. and Lodan, J. D. (1993). Photovoltaics and rural electrification programme
in Nigeria. ISES World Congress, Budapest (Hungary) 24-27 Aug.
Chendo, M.A.C. and Ugoji, E.O. (1994). Solar disinfection of water using beam-splitting
technique. International Renewable Energy Journal 5: 2385-2388.
Costerton, J. W., Lewandowski, Z., Caldwell, D. E., Korber, D. R. and Lappin-Scott, H. M.
(1994). Microbial biofilms. Annual Reviews of Microbiology 49: 711-745.
Fagbemi, J. F., Ugoji, E.O., Adenipekun, T. and Adelowotan, O. (2009). Evaluation of the
antimicrobial properties of unripe banana (Musa sapientum L.), lemon grass
(Cymbopogon citrates S.) and turmeric (Curcuma longa L.) on pathogens. African
Journal of Biotechnology 8(7): 1176-1182.
31
Fuqua, W. C. and Greenbeerg, E. P. (2002). Listening in on bacteria: acyl-homoserine lactone
signaling. Nature Reviews Molecular Cell Biology 3: 685:695.
Gazso, L. G. (2001). The key microbial processes in the removal of toxic metals and
radionuclides from the environment. (a review). Central European Journal of
Occupational and Environmental Medicine 7(3): 178-185.
Kosolapov, D. B., Kuschk, P., Vainshtein, M. B., Vatsourina, A. V., Weibner, A., Kasterner,
M. and Miler, R. A. (2004). Microbial processes of heavy metal removal from carbon
deficient effluents in constructed wetlands. Engineering Life Sciences 4(5): 403-411.
Makin, S. A. and Beveridge, T. J. (1996). The influence of A-band and B-band
lipopolysaccharide on the surface characteristics and adhesion of Pseudomonas
aeruginosa to surfaces. Microbiology 142: 299-307.
Mohammed, S. H., Seady, M. A., Enan, M. R., Ibrahim, N. E., Ghareeb, A. and Moustafa, S.
A. (2008). Biocontrol efficiency of Bacillus thuringiensis toxins against root-knot
nematode, Meloidogyne incognita. Journal of Cell and Molecular Biology 7: 57-66.
Nwachukwu, S. C. U. and Ugoji, E. O. (1993). Studies on organisms associated with
“Kargasok
tea” production. Journal of Scientific Research and Development
1(1):57-60.
Nwachukwu, S. C. U. and Ugoji, E. O. (1995). Impact of crude petroleum spills on microbial
communities of tropical soils. International Journal of Ecology and Environmental
Sciences 21: 169-176.
Nwokoye, N. N., Egwari, L. O., Coker, A. O., Olubi, O. O., Ugoji, E. O. and Nwachukwu, S.
C. U. (2012). Predisposing and bacteriological features of otitis media.
African
Journal of Microbiology Research 6(3):520-525.
Nwuche, C. O. and Ugoji, E. O. (2008). Effects of heavy metal pollution on the soil
microbial activity. International Journal of Environmental Sciences and Technology
5(3): 409-414.
Nwuche, C. O. and Ugoji, E. O. (2010). Effect of co-existing plant species on soil microbial
activity under heavy metal stress. International Journal of Environmental Science
and
Technology 7(4): 697-704.
Obi, C. L., Ugoji, E. O., Edun, S. A., Lawal, S. F. and Anyiwo, C. E. (1994). The
antibacterial effect of honey on diarrhoea-causing bacterial agents isolated in Lagos,
Nigeria. African Journal of Medicine and Medical Sciences 23(3): 257-260.
Odeyemi, O., Salami, A. and Ugoji, E. O. (1988). Effect of common pesticides used in
Nigeria on soil microbial population. The Indian Journal of Agricultural Sciences
58(8): 624-628.
32
Opere, B. O., Ugoji, E. O. and Aboaba, O. O. (2003). In-vivo evaluation of Lactobacillus
species as probiotics in the control of shigellosis in infants. Advances in Food
Sciences 25(3): 112-116.
Opere, B., Aboaba, O. O., Ugoji, E. O. and Iwalokun, B. A. (2012). Estimation of nutritive
value, organoleptic properties and consumer acceptability of fermented cereal gruel
(OGI). Advance Journal of Food Science and Technology 4(1):1-8.
Poudrier, J. K. (2003). Can microgravity change a bacterium’s virulence? Space Research 3:
10-11.
Sani, R. K., Peyton, M. B. and Jadhyala, M. (2003). Toxicity of lead in aqueous medium to
Desulfovibrio desulfuricans G20. Environmental Toxicology 22(2):252-260.
Sifri, C. D. (2008). Quorum sensing: bacteria talk sense. Clinical Infectious Diseases 47:
1070-1076.
Ugoji, E. O. (1993). Fungi in rhizoplane and rhizosphere of Abelmoschus esculentus L.
Nigerian Journal of Botany 6: 61-69.
Ugoji, E. O. and Aboaba, O. O. (2004). Biological treatments of textile industrial effluents in
Lagos metropolis. Journal of Environmental Biology 25(4): 497-502.
Ugoji, E. O. and Laing, M. D. (2008). Rhizotron studies on Zea mays L. to evaluate
biocontrol activity of Bacillus subtilis. World Journal of Microbiology and
Biotechnology 24: 269-274.
Ugoji, E. O. and Uduebo, A. E. (1986). Histochemical investigation on yam tubers infected
with Botryodiplodia theobromae. International Biodeterioration 22(4): 301-306.
Ugoji, E. O., Egwari, L. O. and Obisesan, B. (2000). Antibacterial activities of aqueous
extracts of ten African chewing sticks on oral pathogens. Nigerian Journal of Internal
Medicine 3(1): 7-11.
Ugoji, E. O., Laing, M. D. and Hunter C. H. (2005). Colonization of Bacillus spp. on seeds
and in plant rhizoplane. Journal of Environmental Biology 26(3): 459-466.
Ugoji, E. O., Laing, M. D. and Hunter, C. H. (2006). An investigation of the shelf-life
(Storage) of Bacillus isolates on seeds. South African Journal of Botany 72: 28-33.
Utgikar, V. P., Chaudhary, N., Koeniger, A., Tabak, H. H., Haines, J. R. and Govind, R.
(2004). Toxicity of metals and metal mixtures. Analysis of concentration and time
dependence for zinc and copper. Water Research 38(7): 3651-3658.
Wang, H. R., Wang, M. Z. and Yu, L. H. (2009). Effects of dietary protein sources on the
rumen microorganisms and fermentation of goats. Journal of Animal and Veterinary
Advances 7: 1392-1401.
33