Download Prokaryotes, Eukaryotes, and Non

Prokaryotes, Eukaryotes, and
Non-living Infectious Particles
Introduction to Microbiology
Common Pathogens
The Prokaryotes
Proteobacteria
• All Gram-negative
• Many pathogens. Also organisms that do
nitrogen fixation
• Most use flagella for movement; some nonmotile or use gliding motility
• Alpha, Beta, Gamma, Delta and Epsilon
Alphaproteobacteria
Rickettsiaceae; Cell Symbionts
Bartonella – causes cat scratch disease
Betaproteobacteria
• Aerobic or facultative bacteria that are often
highly versatile in their degradation capacities
• Contains mostly human pathogens
– Example: Neisseria species.
The Betaproteobacteria
• Bordetella
– Chemoheterotrophic;
rods
– B. pertussis
• Burkholderia
– Nosocomial
infections
Figure 24.7
Gammaproteobateria
• Class of several medically, ecologically and
scientifically important groups of bacteria
• Includes Pseudomonas aeruginosa, Vibrio
species (Cholera), E. coli, Salmonella species,
Shigella species, etc.
The Gammaproteobacteria
• Pseudomonadales
– Pseudomonas
• Opportunistic
pathogens
• Metabolically
diverse
• Polar flagella
Figure 11.7
The Gammaproteobacteria
• Vibrionales
– Found in coastal
water
• Vibrio cholerae
causes cholera
• V. parahaemolyticus
causes
gastroenteritis
Figure 11.8
The Gammaproteobacteria
•
•
•
– Peritrichous flagella;
facultatively anaerobic •
•
•
•
•
•
• Enterobacteriales
(enterics)
Enterobacter
Erwinia
Escherichia
Klebsiella
Proteus
Salmonella
Serratia
Shigella
Yersinia
More Gammaproteobacteria
Figure 11.9b
Yersinia Pestis – causative agent of the
Black Plague
Yersinia enterocolitica
Causes Yersinosis; enterocolitis. Zoonotic disease.
The Epsilonproteobacteria
• Helicobacter
– Multiple flagella
– Peptic ulcers
– Stomach cancer
Figure 11.12
Epsilonproteobacteria
• Mainly the curved/spirilla
• Most of the known species inhabit the
digestive tract of animals and serve as
symbionts or pathogens(
– Helicobacter spp. in the stomach
– Campylobacter spp. in the duodenum.
Epsilonproteobacteria
• Campylobacter jejuni – causes food borne
intestinal illness.
Gram-Positive Bacteria - Firmicutes
• Low G + C
• Gram-positive
Clostridiales
Gram positive; spore producers; obilgate
anaerobes
• Clostridium
Figure 11.15
Gangrene – caused by C. perfringens
Bacillales
Gram positive; aerobic of facultative anaerobes; Bacillus, Listeria
and Staphylococcus
• Staphylococcus
– Cocci
Figure 11.18
Staph Infection
Lactobacillales
• Generally
aerotolerant
anaerobes; lack
an electrontransport chain
[Insert Figure 11.19]
– Lactobacillus
– Streptococcus
– Enterococcus
– Listeria
Figure 11.19
Actinobacteria
• High G + C
• Gram-positive
Actinobacteria
•
•
•
•
•
•
•
•
Actinomyces
Corynebacterium
Frankia
Gardnerella
Mycobacterium
Nocardia
Propionibacterium
Streptomyces
Chlamydias
obligate intacelluar parasites; unique life cycles
• Chlamydia
trachomatis
– Trachoma
– STI, urethritis
• Chlamydophila
pneumoniae
• Chlamydophila psittaci
– Psittacosis
Figure 11.24b
Life Cycle of the Chlamydias
Figure 11.24a
Spirochetes
All posses axial filaments
• Borrelia
• Leptospira
• Treponema
Figure 11.25
Bacteroidetes
• Gram negative, non-sporeforming, anaerobic, and
rod-shaped bacteria that are widely distributed in
the environment, including in soil, in sediments, sea
water and in the guts and on the skin of animals.
• Bacteroides are found in the mouth and
large intestine
• Cytophaga: Cellulose-degrading in soil
Fusobacteria
-
-
-
Fusobacterium is a Gramnegative non-sporeforming
bacterium that is widely
known and studied as a
human and animal
pathogen.
Fusobacterium's
exceptional ability to
adhere with both Gramnegative and Grampositive plaque
microorganisms in biofilms
(specifically in soft tissue)
has made it a highly
invasive pathogen.
Primarily given attention
for its peridontal
implications
- Strains of
Fusobacterium have
been identified as
pathogen to many
parts of the body
Figure 11.26
Domain Archaea
Extremophiles
• Hyperthermophiles
– Pyrodictium
– Sulfolobus
• Methanogens
– Methanobacterium
• Extreme halophiles
– Halobacterium
Microbial Diversity
• PCR indicates up to 10,000 bacteria per gram of
soil.
• Many bacteria have not been identified because
they
– Haven't been cultured
– Need special nutrients
– Are a part of complex food chains requiring the
products of other bacteria
– Need to be cultured to understand their metabolism
and ecological role
The Eukaryotes: Fungi, Algae, Protozoa, and
Helminths
Fungi
Kingdom
Fungi
Nutritional Type
Chemoheterotroph
Multicellularity
All, except yeasts
Cellular Arrangement
Unicellular, filamentous,
fleshy
Food Acquisition Method
Absorptive
Characteristic Features
Sexual and asexual spores
Embryo Formation
None
Mycology is the study of fungi
Molds
• The fungal thallus consists of hyphae; a mass
of hyphae is a mycelium.
Figure 12.2
Yeasts
• Unicellular fungi
• Fission yeasts divide symmetrically
• Budding yeasts divide asymmetrically
Figure 12.3
Fungal Dimorphism
• Pathogenic dimorphic fungi are yeastlike at 37°C and moldlike
at 25°C
Figure 12.4
Medically Important Phyla of Fungi
• Zygomycota – saprophtyic molds (bread mold);
mucor
• Ascomycota – sac fungi; Candida albicans and
Aspergillus flavus
• Anamorphs – produce asexual spores only; ringworm
(tinea) and dermatophytes
– Basidiomycota – club fungi
– Teleomorphic fungi – produce sexual and asexual
spores
• Cryptococcus (yeast-like state causes disease)
Zycomycota - Mucormycosis
Dermatophyte – capable of
utilizing keratin
Cryptococcus
Aspergillosis
Candidiasis
Algae
Kingdom
Protist
Nutritional Type
Photoautotroph
Multicellularity
Some
Cellular Arrangement
Unicellular, colonial,
filamentous, tissues
Food Acquisition Method
Diffusion
Characteristic Features
Pigments
Embryo Formation
None
Diatoms – produce neurotoxins
Dinoflagellates
• Cellulose in plasma
membrane
• Unicellular
• Chlorophyll a and c,
carotene, xanthins
• Store starch
• Some are symbionts in
marine animals
• Neurotoxins cause
paralytic shellfish
poisoning
Figure 12.13
Oomycota
• Decomposers and
plant parasites
– Phytophthora
infestans
responsible for
Irish potato blight
– P. cinnamoni
infects Eucalyptus
– P. ramorum
causes sudden
oak death
Figure 12.14
Protozoa
Kingdom
Protist
Nutritional Type
Chemoheterotroph
Multicellularity
None
Cellular Arrangement
Unicellular
Food Acquisition Method
Absorptive; ingestive
Characteristic Features
Motility; some form cysts
Embryo Formation
None
Medically Important Phyla of Protozoa
•
•
•
•
•
•
Archaezoa
Microspora
Amoebozoa
Apicomplexa
Ciliophora
Euglenozoa
Archaezoa
•
•
•
•
No mitochondria
Multiple flagella
Giardia lamblia
Trichomonas
vaginalis (no cyst
stage)
Figure 12.16b
Archaezoa
Figure 12.16c, d
Microspora
Opportunistic parasites. Intracelluar development and
spore formation
• Microsporidia
Amoebozoa
• Move by
pseudopods
• Entamoeba
• Acanthamoeba
Figure 12.17a
Apicomplexa
•
•
•
•
•
•
•
Nonmotile
Intracellular parasites
Complex life cycles
Plasmodium
Babesia
Cryptosporidium
Cyclospora
The Life Cycle of Plasmodium vivax
2
3
8
7
6
Figure 12.18
Cryptosporidium
Clinical Focus, p. 355
Ciliates
• Move by cilia
• Complex cells
• Balantidium
coli is the only
human parasite
Figure 12.19
Euglenozoa
• Move by flagella
• Euglenoids
– Photoautotrophs
Figure 12.20
Euglenozoa
• Move by flagella
• Hemoflagellates
– Trypanosoma
spp.
• Sleeping
sickness
• Chagas’ disease
Figure 23.22
Helminths
Kingdom
Animalia
Nutritional Type
Chemoheterotroph
Multicellularity
All
Cellular Arrangement
Tissues and organs
Food Acquisition Method
Ingestive; absorptive
Characteristic Features
Elaborate life cycles
Embryo Formation
All
Helminths (Parasitic Worms)
• Kingdom: Animalia
– Phylum: Platyhelminthes (flatworms)
• Class: Trematodes (flukes)
– Tissue and blood flukes
• Class: Cestodes (tapeworms)
– Phylum: Nematoda (roundworms)
Characteristics of Helminths
•
•
•
•
Reduced digestive system
Reduced nervous system
Reduced locomotion
Complex reproduction
The Life Cycle of Trematodes
Figure 12.25
Cestodes, or Tapeworms
Figure 12.26
Human as
Definitive Host –
parasite reaches
maturity
Taenia saginata
Intermediate
Echinococcus
Host – only some granulosus
of the parasite’s
developmental
stages are
complete
Cysticerci in beef
muscle
Adult in dog
Nematodes
Figure 12.28
The Heartworm Dirofilaria immitis
Figure 12.29
Ascaris and Pinworm
Arthropods as Vectors
• May transmit diseases (vectors)
• Kingdom: Animalia
– Phylum: Arthropoda (exoskeleton, jointed legs)
• Class: Insecta (6 legs)
– Lice, fleas, mosquitoes
• Class: Arachnida (8 legs)
– Mites and ticks
Arthropods as Vectors
Figure 12.31
Viruses
•
•
•
•
•
•
Obligatory intracellular parasites
Contain DNA or RNA
Contain a protein coat
Some are enclosed by an envelope
Some viruses have spikes
Most viruses infect only specific types of cells
in one host
• Host range is determined by specific host
attachment sites and cellular factors
Structure
• Nucleic acid
– DNA or RNA
• Capsid
– Capsomeres
• Envelope
• Spikes
Figure 13.2a
Morphology of an Enveloped Virus
Figure 13.3
Morphology of a Helical Virus
Figure 13.4
Morphology of a Complex Virus
Figure 13.5
Taxonomy of Viruses
• Family names end in -viridae.
• Genus names end in -virus.
• Viral species: A group of viruses sharing the
same genetic information and ecological niche
(host). Common names are used for species.
• Subspecies are designated by a number.
Growing Viruses
• Viruses must be
grown in living
cells
– Bacteriophages
form plaques on
a lawn of bacteria
Figure 13.6
Growing Viruses
• Animal viruses
may be grown
in living
animals or in
embryonated
eggs
Figure 13.7
Virus Identification
• Cytopathic effects
• Serological tests
– Detect antibodies against viruses in a patient
– Use antibodies to identify viruses in neutralization
tests, viral hemagglutination, and Western blot
• Nucleic acids
– RFLPs
– PCR
The Lytic Cycle
1
2
3
Figure 13.11
The Lytic Cycle Continued
4
Figure 13.11
The Lysogenic Cycle
Figure 13.12
Oncogenic Viruses – Viruses that can
induce cancer
• Oncogenic DNA
viruses
– Adenoviridae
– Herpesviridae
– Poxviridae
– Papovaviridae
– Hepadnaviridae
• Oncogenic RNA viruses
– Retroviridae
– Viral RNA is transcribed to
DNA, which can integrate
into host DNA
– HTLV-1 (Human T-cell
Lymphotropic Virus; linked
to leukemia)
– HTLV-2 (Human T-cell
Lymphotropic Virus; linked
to hairy cell leukemia)
Latent Viral Infections
• Virus remains in
asymptomatic
host cell for long
periods
– Cold sores,
shingles
Figure 13.21
Persistent Viral Infections
• Disease
processes
occurs over a
long period;
generally is
fatal
– Subacute
sclerosing
panencephalit
is (measles
virus)
Figure 13.21
Prions
• Proteinaceous Infectious particle
• Inherited and transmissible by ingestion,
transplant, and surgical instruments
– Spongiform encephalopathies: Sheep scrapie,
Creutzfeldt-Jakob disease, Gerstmann-SträusslerScheinker syndrome, Kuru, fatal familial insomnia,
mad cow disease
Normal Protein vs. Prion
Scrapie
Creutzfeldt-Jakob