Download Some Differential Characteristics of Procaryotes and Eukaryotes

Some Differential Characteristics of Procaryotes and Eukaryotes
CHARACTERSISTIC
CYTOLOGICAL FEATURES
nucleoplasm (genophore, nucleotide separated from the
cytoplasm by a unti-membrance system of(nuclear membrane)
size of smallest dimension of cells (width or diameter):
usually 0.2-2.0 um
usually >2.0 um
mitochondria present
chloroplast present in phototroph
vacuoles, if present, enclosed by unit membrane
gas vacuoles presents
golgi apparatus present
lysosmes present
microtubular systems present
endoplasmic reticulum present
ribosome location
dispersed in the cytoplasm
attached to an endoplasmic reticulum
cytoplasmic streaming, pseudopodial movement, endocytosis,
and exocytosis either nucleoplasm or cytoplasm
flagella, if present
diameter:
0.01-0.02um
ca. 0.2um
in cross section, have a characteristic " 9+2" arrangement of
microtubules
endospores present
ANTIBOITIC SUSCEPTIBILITY
Susceptible to:
Penicillin, streptomycin, or other antibiotics specific for
prokaryotes
cycloheximde or other antibiotics specific for eukaryotes
FEATURES BASED ON CHEMICAL ANALYSIS
poly B hydroxbutyrate present(as a storage compound in
cytoplasmic inclusions)
teichoic acids present (in cell walls)
polyunsaturated fatty acids possibly present (in membranes).
branched-chain iso-or anteiso-fatty acids and cyclopropane
fatty acids present(in membranes)
PROCARYOTES EUCARYOTES
-
+b
D
-d
+
D
+
+
+
+
+
D
D
D
+
+
D
+
=
+
+
D
-
-
D
-
D
D
D
-
D
Rare
Common
Rare
Common
-
CHARACTERSISTIC
sterols present (in membranes)
diaminopimelic acid present (in cell walls)
muramic acid present (in cell walls)
peptidoglycan (containing muramic acid) present in
cell walls
NUTTRITION
nutrients acquired by cells as soluble small molecules;
to serve as sources of nutrients, particulate matter or
large molecules must first be hydrolyzed to small
molecules by enzymes external to the plasma
membrane
METABOLIC FEATURES
respiratory and photosynthetic functions and
associated pigments and enzymes (e.g. chlorophylls,
Cytochrome), if present, are associated with the
plasma membrane or invaginations thereof
chemolithotrophic type of metabolism occurs
(inorganic compounds can be used as elctr4on donors
by organisms that derive energy from chemical
compounds)
ability to fix N2
ability to carry out anoxygenic photosynthesis
ENZYMES FEATURES
type of super oxide dismutase:
Cu-Zn type
Mn and/or Fe type
REPRODUCTIVE FEATURES
cell division occurs by mitosis, and a micro tubular
(spindle) system is present
meiosis occurs
mechanisms of gener transfer and recombination, if
they occur, involve gametogenesis and zygote
formation
MOLECULAR BIOLIGICAL PROPTERTIES
number of chromosomes present per nucleiod
chromosomes circular
chromosomes linear
sedimentation constant of ribosome's
70S
80S
sedimentation constants of ribosomal RNA
16S, 23S, 5S
18S, 28S, 5.85S, 5S
PROCARYOTES EUCARYOTES
-1
Common
Dg
h
D
h
D
-
+
D
+1
-
D
-
D
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
CHARACTERSISTIC
MOLECULAR BIOLOGICAL PROPERTIES
(CONTINUED)
first amino acid to initiate a polypeptide chain during
protein synthesis:
Methionin
N-Formymethionin
messenger-RNA binding site at AUCACCUCC at 3
end of 16S or 18S ribosomal RNA
PROCARYOTES EUCARYOTES
-
-
+b
-
+b
-
a. Symbols: +, positive;-, negative; D, differs among organisms.
b. A few bacteria (e.g., certain treponemes, mycoplasmas, haemobartonella) may have a
width as small as 0.1 um; a few bacteria (e.g., Achromatium, Macromonas) may have
a width greater than 10 um.
c. Gas vacuoles are not bounded by a unit membrane. The vesicles composing the
vacuoles can be caused to collapse by the sudden application of hydrostatic pressure- a
feature essential to their identification.
d. However, certain intracellular fibrils that may be microtubules have been reported in
Spiroplasma, certain spirochetes, the cyanobacterium Anabaena, and in bacterial L
forms...
e. Bacterial ednospores are usually resistant to heat treatment of 80C or more for 10 min.
however, some types of endospores may be killed by this heat treatment and may
require testing at lower temperatures.
f. Except in membranes of most mycoplasmas.
g. Present in virtually all gram-negative eubacteria and in many gram-positive bacteria.
h. Present in walled eubacteria except Chlamydia; absent in archaeiobacteria
i. However in cyanoabacteria there may be
j. With a few rare exceptions, such as certain phtobacteria.
k. Except in mitochondria, in which the Mn type occurs.
l. Except in mitochondria and chloroplast, which have 70S ribosomes.
CHAPTER IV
THE FOUR MAJOR CATEGORIES OF BACTERIA
The four major (on a phenotypic basis) categories of bacteria are described briefly below,
followed by tables of characteristics useful for differentiating some of these categories.
1. gram negative Eubacteria that have cell walls
these are prokaryotes that have a complex (gram-negative type) cell-wall profile consisting of
an outer membrane and an inner, thin peptidoglycan layer which contains muramic acid and is
present in all but a few organisms that have lost this portion of wall) and a variable
complement of other components outside or between these layers. They usually stain gram
negative. Cell shapes may be spheres, ovals, straight or curved rods, helices, or filaments;
some of these forms may be sheathed or capsulated. Reproduction is by binary fission, but
some groups show budding, and a rare group (pleurocasples) shows multiple fission. Fruiting
bodies and myxospores may be formed by the mycobacterium. Swimming motility, gliding
motility, and nonmotility are complying observed.
Members of the division may be
phototrophic or no phototrophic (both lithotrophic and heterotrophic) bacteria and include
aerobic, anaerobic, facultative) anaerobic, and microaerophilic species some members are
obligate intracellular parasites.
II gram positive eubacteria that have cell walls profile of the gram positive type; reaction with
grams' stain generally, but not always, is positive. Cells may be spheres, rods, or filaments
the rods and filaments may be none branching, but many show true branching. Cellular
reproduction is generally by binary fission; some produces spores as restings forms
endospores or spores on hyphae). They are not photosynthetic; generally, they are
chemosynthetic heterotroph and include aerobic, anaerobic, facultative anaerobic, and
Microaerophile species. The members of this division include simple asporogenous and
asporogenous bacteria, as well as the actinomycetes and their relatives.
IIIEubacteria lacking cell walls
There are prokaryotes that lack cell walls (commonly called the mycoplasmas and including
the class Mollicutes) and do not synthesize the precursors of peptidoglycan.
They are
enclosed by a unit membrane. The cells are highly Pleomorphic and range in size from large
deformable vesicles to very small (0.2um), filterable elements. Filamentous forms with
branching projections are common. Reproduction may be by budding, fragmentation and or
binary fission some groups who a degree of regularity of form due to the placing of internal
structures. Usually, they are nonmotile, but some species show a form of gliding motility.
No resting forms are known. Cells stain gram negative.
Most require complex media for
growth (high-osmotic-pressure surroundings) and tend to penetrate the surface of solid media
forming characteristic friend egg colonies. The organisms resemble the naked L-forms that
can be generated from many species of bacteria (notably gram positive eubacterial) but differ
in that the mycoplasmas are unable to revert and make cell wall. Most species are further
distinguished by requiring both cholesterol and long-chain fatty acids for growth; unesterified
cholesterol is a unique component of the membranes of both sterol requiring and nonrequiring
species if present in the medium. The guanine plus cytosine content of ribosomal RNA is 4348 mol% 9lower than the 50-54 mol% of walled gram negative and gram positive eubacteria);
the guanine plus cytosine content of the DNA is also comparatively low, 23-46 mol% and the
genome size of the mycoplasmas is less than that the other prokaryotes at 0.5-1.0 x 10
Daltons. The mycoplasmas may be saprophytic, parasitic, or pathogenic, and the pathogens
cause disease of animal’s plants, and tissue cultures.
IV Archaeiobacteria
The arch bacteria are predominantly terrestrial and aquatic microbes, occurring in anaerobic
hyper saline or hydrothermally and geothermally heated environment; also, some occur
symbionts in animal’s digestive tracts. They consist of aerobes anaerobes, and facultative
anaerobes that grow chemolithoauthotrophically, orgnaorrophically, Archaeobacteria may be
mesophiles or thermophiles, with some species growing even above 100C
A unique biochemical feature of archaeiobacteria is the presence of glycerol isopranyl ether
lipids. The lack of murein (peptidoglycan-containing muramic acid) in cell walls makes
archaeiobacteria insensitive to B lactam antibiotics. The common arm of the RNAs contains
pseudouridineor 1-methylpseudourindine instead of ribothymidine. The sequences of 5S,
16S, and 23S RNAs are very different from the corresponding ones in eubacteria and
eucaryotes.
Archaeiobacteria share some molecular features with eukaryotes: (a ) the elongation factor
2(EF-2) contains the amino acid diphthamide and is therefore ADP-ribosylable by diphtheria
toxin, (b) amino acid sequences of the ribosomal A protein exhibit sequence homologies with
the corresponding eukaryotic (L-7/L-12) protein, (c) the methionyl initiator RNA terminates
with the base paid AU (f) the DNA dependent RNA polymerases re multi component
enzymes and are insensitive to the antibiotics rifampicin and streptolydigin (g) like the DNA
polymerases of eukaryotes are not inhibited by aphidicolin or burylphenyl dGTP, and (h)
protein synthesis is inhibited by anisomycin but not by chloramphenical
Autotrophic archaeiobacteria do not assimilate carbon dioxide via the Calvin cycle, in
Methoanobacterium CO is fixed via an acetyl CoA pathway, whereas in acidianus and
thermoproteus autotrophic CO is fixed via a reductive tricarboxlylic acid pathway. Fixation
of N ahs been demonstrated by some methnogens.
Gram stain results may be positive or negative within the same order because of very different
types of cell envelopes. Gram positive species posses pscudomurein, methanochondroitin,
and heteropolysaccharide cell walls gram negative cells have (glycol) protein ride cell walls,
gram negative cells have the cells may have a diversity of shapes including spherical spiral
plate or rod shaped unicellular and multicellular forms in filaments or aggregates also occur
the diameter of anindividual cell may be 0.1-15 um, and the length of the filaments can be up
to 200um.
Multiplication is by binary fission, budding, constriction, fragmentation or
unknown mechanism colors of cell masses may be red, purple, pink, orange brown, yellow
green greenish black, gray, and white.
The major groups of archaobacteria include (a) the methanogenic archaeiobacteria, (b) the
archaeiobacteria sulfate reducers, (c) the extremely Halphilic archaeiobacteria, (d) the cell
wall less archaeiobacteria, and (e) the extremely thermophilic metabolizes.
CHARACTERSISTIC
GENERAL MORPHOLOGIC AND
METABOLIC FEATURES
Strict anaerobes that form methane as the
predominant metabolic end product from H2CO2, format, acetate, methanol, methylamine
or H2 methanol. Cells exhibit a blue green
epifluroescence when excited at 420mm
Strict anaerobes that form H2S from sulfate by
dissmilatory sulfate reduction. Extremely
Thermophilic (growth up to 92 C) exhibit blue
green epifluroescence when excited at 420mm
Cells stain gram negative or gram positive and
are aerobic or facultative anaerobic
Chemoorganotroph. Rods and regular to
highly irregular cells occur; cells require a
high concentration of NaCl (1.5 More above)
Neutrophilic or Alkaliphilic. Mesophilic or
slightly Thermophilic (up to 55C) some
species contain the red- purple photoactive
pigment bacteriorhodopsin and are able to use
light for ATP synthesis
Thermoacidophilic, aerobic, facultative
anaerobic or strictly anaerobic gram negative
rods, filaments, or cocci. Optima growth
temperature between 70C and 105C
acidophilus and Neutrophilic autotrophic or
heterotrophic most species are sulfur
metabolizes
PROCARYOTES ARCHAEOBACTERIA
-
-
+b
+b
-
-
-
-
CELL WALLS(IF PRESENT)
contain muramic acid
ANTIBIOTIC SUSCEPTIBILITY
susceptible to penicillin or other antibiotics that inhibit
synthesis of muramic acid containing peptidoglycan
LIPIDS
membrane phospholipids consist of long chain
alcohol(phytanois) that are either linked to glycerol to
form C20 diphytanyl glycerol diethers or C40
dibiphytanyl digilycerol tetraethers
long chain aliphatic fatty acids that are ester linked
toglycerol
pathway used in formation of lipids:
mevalonate pathway malonate pathway
MOLECULAR BIOLOGICAL FEATIURES
ribothymine is present in the common arm of the RNA
pseudouridine or 1methylpseudourindine is present in
the common arm of the RNA
CHARACTERSISTIC
First amino acid to intiate a polypeptide chain
during protein synthesis.
Methionin
N-F formylmethiorine
aminoacyl stem of the initiator IRNA
terminates with the base pair AU
protein synthesis by ribosomes inhibited by
anisomycin
kanamycin
chloramphenicol
ADPRibosylation of the peptide elongation
factor EF-2 is inhibited by diphtheria toxin
Elongation factor 2(EF-2) contains the amino
acid diphthamide.
Some RNA genes contain introns.
DNA-dependent RNA polymerases are
multicomponent enzymes
inhibited by rifampicin and streptolydigin
replicating DNA polymerases are inhibited by
aphidicolin or butylphenyl d GTP
Symbols+, positive,-, negative D differs among organisms
-
-
+b
-
+b
-
-
-
-
-
D
-d
D
-d
PROCARYOTES ARCHAEOBACTERIA
-
-
+b
-
+b
-
D
-
D
-
-
-
-d
-
-d
-
Some of the characteristics differtiating eubacterial Major form eubacterial major coategory
CHARACTERSISTIC
MAJOR
MAJOR
CATEGORY 1 CATEGORYII
CYTOLOGICAL FEATURES
gram staining reaction
an outer membrane is present in the cell wall in
addition to the plasma cytoplasm membrane
+b
+b
acid fast staining
endospores present
filamentous growth with hyphae that show true
branching
LOCOMOTION
Gliding motility occurs.
D
D
CHEMCIAL FEATURES
percentage of the dry weight of the cell wall that is
represent by lipid
teichoic or lipteichoic acids present
lipopolysaccharide (LPS) occurs ( in the outer
membrane of the cell wall)
-d
-d
2-keto-3-deoxyoctonate (KDO) present
percentage of the dry weight of the cell wall is
represented by peptidoglycan
mycolic acids present
phosphatidylinositol mannosides present
+
+
METABOLIC FEATURES
energy derived by the oxidation of inorganic iron,
sulfur or nitrogen compounds
ENZYMIC FEATURES
D
D
citrate synthesis:
inhibited by reduced nicotinamide adenine
dinulceotide (NADH) molecular weight
ca 250, 000
D
D
ca 100,000
succinate thiokinases, molecular weight of
70,000-75,000
D
D
140,000-150,000
a.
b.
c.
d.
e.
f.
g.
Symbols: +, positive;-, negative, D, differs among organisms.
B the staining reaction may not be conclusive. A few bacteria that have a gram positive type of cell
wall profile and whose wall contain teichoic acids may stain gram negative, probably because of the
thinness of the wall. For example, see the genus butyrivibrio.
The staining reaction may not be conclusive. A few bacteria that have a gram-negative type of cell wall
profile and whose walls contain lipopolysaccharide may stain gram positive for example, see the genus
xanthobacter.
An exception may be the genus coxeilla.
Acid fast staining occurs in the genus mycobacterium and in some nocardia species.
Endospores occur in the general bacillus, clostridium desulfotomaculum sporosarcina, and
thermoactinomyces
Except for mycobacterium corynebacteruim nocardia, and other genera whose walls contain mycolic
acids.
h.
LPS consists of lipid A (a B-linked d-glucosamine disaccharide to which phosphate residues are linked
at positions 1 and 4 and fatty heteropolysaccharide) and Oantigens9side chains that are polysaccharide
composed of repeating unties)
i. In many but not all gram negative bacteria, the core polysaccharide contains KDO which, if present, can
serve as an indictor of the presence of LPS.
j. Mycolic acids occur in corynebacterium nocardia, mycobacterium bacterionema, faenia, and
rhodocccus.
k. For example in bacteroides
l. Known exception include acetobcter, thermos, and cyanoabacteria
m. One know exception is thermos.,
Cytochrome
one of various inron-prophyrins that can undergo reversible oxidation reduction and
that serves as an electron carrier in an electron transport chain.
Endospore
a thick-walled spore formed in a bacterial cell. It is very resistant to being killed by
heat and various other chemical and physical agents. Endospores are best verified by
demonstrating that cultures survive a temperature of 70-80C for 10 min.
Facultative anaerobe
an organism that can grow well both in the absence of oxygen and in the presence of a
level of oxygen equivalent to that in an air atmosphere (21%oxygen). Some are
capable of throwing aerobically by respiring with oxygen and of growing
be fermentation. Others have a strictly fermentative type of metabolism and
respire with oxygen.
anaerobically
not
Fermentation
an energy yielding metabolic process in which electrons derived from an organic
substrate are used ultimately to reduce an organic electron acceptor that is made by
the cell itself. Neither an electron transport chain nor an exogenous terminal electron
acceptor is involved. (Contrast with respiration)
Flavin
an enzymes that contains as tightly bound prosthetic groups either flavin
mononucleotide (FMN) or flavin adenine dinucleotide (FAD)
Fruiting body
a specialized sore-producing structure that is composed of slime and bacterial cells, is
often brightly colored, and may be visible to the naked eye. Formed by myxobacteria.
Gas vacuole
a cavity in the cytoplasm that contains gas of composition similar to that of
the surrounding atmosphere. The boundary of the cavity is membrane consisting of
protein subunits. Gas vacuoles appear as bring areas within a cell by passé contrast
microscopy and are identified by their ability to collapse when the cells are
subject to a sudden increase in hydrostatic pressure.
Gliding motility
a type of movement across surface that is exhibited by some bacteria devoid of
flagella and incapable of swimming motility
Gram variable
some gram positive cell occur in an otherwise gram negative pure culture.
Halphilic
growing best at high Na C concentrations.
Heterotroph
growing in three dimensions and having one or more turns; corksxerw-shaped
Hyphae
the individual filaments or threads of mycelium
Meanquinoes
vitamins K. 2-methyl-3-all trans polyprenol-1, 4-naphatroquinones possessing side
chains varying in length from C5 C65. Meanquinoes function as electron carriers
Mesophilic
growing best at a moderate temperature range (25-40C)
Methanogenic
producing methane
Microaerophile
an organism that is capable of oxygen dependent growth but cannot grow in the
presence of a level of oxygen equivalent to that present in an air atmosphere
(21%oxygen). Oxygen dependent growth occurs only at low oxygen level. In
addition to being able to respire with oxygen, some Microaerophile may be capable
of respiring anaerobically with electron acceptors other than oxygen.
Mutualism
a type of interaction in which two or more organisms living together benefit each
other.
Mycelium
a mass or network of interwoven filaments (hyphae).