e- e- e- e- Fisiología microbiana Bota 6006 endoespora células hijas(1-7) flagelo tallo Thiomargarita namibiensis 1m m Bdellovibrio
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Fisiología microbiana Bota 6006
endoespora
células hijas (1-7)
flagelo
tallo
Thiomargaritanamibiensis
1mmBdellovibrio
1 ~1500 nucleotides
Secondary structure of 16S rRNA
Evolutionary distance - # de nucleótidos diferentes y se usan para calcular distancia.Maximum parsimony - # de nucleótidos diferentes, sus posiciones y la naturaleza
de las diferencias.
• Tres linajes distintivos (2 Prokarióticos/1 Eucariótico) Archaea, Bacteria & Eucaria
• la raíz del árbol de la vida representa una forma ancestral común
• Archaea & Eucaria son evolutivamente más relacionados
•Archaea están evolutivamente más cercanas a la forma ancestral (más primitivos).
• Eucariotas están más distanciados de la forma ancestral (más evolucionados)
• origen termofílico de los seres vivos
EL ARBOL DE LA VIDA
basado en secuencias de
genes de RNA ribosomal 16S
Caracteristicas Bacteria Archaea Eukarya
Peptidoglycan Yes No NoLipids Ester linked Ether linked Ester linked
Ribosomes 70S 70S 80SInitiator tRNA formyl-Met Met MetIntrons in tRNA No Yes YesRibosomes sensitive to diphteria toxins
No Yes Yes
RNA polymerase 1
(4 subunits)
Several
(8-12 subunits)3
(12-14 subunits)
Histones No Yes Yes
Prokaryotic cell wall
The primary function of the CW is to protect the cell from bursting. There areonly two types of CW in Bacteria:
PeptidoglycanChemical structure
G+ Cell Wall
15-30 nmthick
Covalently linkedTo the peptidoglycan
N-acetil ácido murámico (mureína)
Attachment to peptidoglycan
or glycerol
Teichoic acid attachment
Polyanionic polymers of ribitol-PO4Or glycerol-PO4.
Lipido AEndotoxina, fiebre, necrotización de tejidos fallocardíaco
Polisacárido medularPolisacárido O-específicodesata reacciones alérgicas
LPS
It produce a permeability barrier to hydrophobic compounds:antibiotics, dyes (eosin-methylene blue), bile salts
Porin are major proteins in the outer envelop that form small non-specifichydrophilic channels that allow the diffusion of low molecular weightneutral or charged solutes. Examples are LamB, OmpF, OmpC, Tsx.
Periplasm It is a aqueous compartment containing protein, salts,oligosaccharide, and peptidoglycan.
What happens in this space?Specialized activities such as
1) oxidation-reduction reactions2) osmotic regulation3) solute transport4) protein secretion5) degradation by phosphatasesand nucleases.6) Detoxification
Cell membrane
Responsible for solute transport, electron transport, photosynthetic electron transport,the establishment of electrochemical gradients, ATP synthesis, biosynthesis of lipids,biosynthesis of cell wall polymers, secretions of proteins, the secretion and uptake of intercellular signals, and responses to environmental signals.
>100 differentProteins. Integraland peripheral.
Ácidos grasos
Rol estructural en la membrana citoplasmica
Archaea
Cytoskeleton
FtsZ is a cell division protein related to tubulin.
Phase contrast
Nucleoid stain
FtsZ stain
Nucleoid stainFtsZ stain
Streptococcus hemolyticus
Wall band
perítrico monotricolofótrico
amfitrico
Bacterial Flagella
Los flagelos son filamentos helicoidales y rígidos de un diámetro de ~20nmy que rota como una hélice.
Estos consisten de: basal body, a hook, filament, motor, switch, exportapparatus, capping and junction proteins.
Basal BodyMS ring
FliF protein
FlgH protein
FlgI protein
Central rodFlgB,C,F
Flagella and its components
C ring
The motor
Startor (MotA, B proteins)
Rotor (FliG proteins)
C ring (FliM, N)
H+ pass across the CM thru the MotA,Bwhich provide the torque to rotate the rotor.
The motor: how does it change direction?
Startor (MotA, B proteins)
Rotor (FliG proteins)
C ring (FliM, N)
The direction of the rotation results in the direction of the cell (North, south…) and this is related to CheY-P which are chemotactic proteins and binds FliM.
Chemiotactic effect on motility
The motorFliC is not identical in all bacteria.20 to 65 kD more importantly only the C and N-terminal seem to be conserved(~60%). The filament grows from the hookTo the capping protein by adding flagellin monomers as it needs.
Furthermore, a cell could have more than one type of flagellin. E. coli (1),Caulobacter sp. (3).
Summary of steps in Flagella biosynthesis
Gram-negative Bacteria