Bacterial spore physiology.pdf

PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY,SRI PARAMAKALYANI COLLEGE,ALWARKURICHI.

1. BACTERIAL SPORE

2. Synopsis
•Definition
•Spore-forming bacteria
•Structure
•Shape and position
•Exospore
•Endospore
•Sporulation
•Reference

3. Definition
•It is a unicellular structure.
•Spores form a life cycle in many plants, algae, bacteria, fungi
and protozoa.
•Spores are formed during unfavorable conditions.
•They can survive without nutrients.
•It forms highly resistant structure.

4. •Bacterialsporesaresmallovalorsphericalstructuresthatare
veryresistanttohightemperatures,radiation,desiccation,and
chemicalagents.
•Whentheyareformedintracellularly,theyarecalled
endospore.
•Thebacterialcellproducingsporeiscalledvegetativecell.

5. Spore-forming bacteria
Bacillus:
Bacillus anthracis
Bacillussubtilis
Bacilluscereus
Bacillusclausii
Bacillushalodenitrificans
Clostridium:Clostridiumbotulinum, Clostridiumdifficile,
Clostridiumperfringens
Thermophilic actinomycetes:
Thermoactinomycesvulgaris

6. structure

7. •Theouterandinnercoatmadeupofproteinandtheyprovides
chemicalandenzymaticresistancetothespores.
•Cortexregionliesbetweentheregionofouterandinnercoatandit
ismadeupofpeptidoglycon.
•Cortexhelpsindehydrationprocessduringsporulationprocessand
thusprovidinghightemperatureresistance.

8. Shape and position
Shape
•Spherical,ovalorelongatedinshape
•Maybenarrowerorbroader(bulge)thanparentcell

9. Position
•Terminal (located at one of the poles)
•Sub terminal or sub central(between center & one ofpoles
•Equatorial (central)

10. Bacteria can be classified based on the shape
and position of spores.

11. Bacterial spores undergoes two types of
formation :

12. Endospore;
•Formedinsidetheparentvegetativecell.
•Endosporesarehighlydurabledehydratedcells,whichcansurvive
extremeheat,lackofwater,freezingandexposuretomanytoxic
chemicalsandradiation.
•Endosporesalsocalledas“restingcells”.

13. Exospore;
•Formed outside the vegetative cell by budding at one end of
the cell.
•The Exospore do not contain dipicolinic acid.
•They can resist desiccation and heat.

15. Exospores development
•exospores formation spores developed outside the body.
•They developed attached with a outer surface of the cell
wall.
•During the unfavorable conditions Primarily, the mother cell
and the daughter cells are divided by means of the septum
and later it forms a bud like structure at the outer covering.

17. Endospore formation in some Epulopiscium-like
symbionts follows a daily cycle:
A)Polarseptaareformedatthepolesofthecell.
B)Foresporesbecomeengulfed.
C)Foresporesgraduallyincreaseinsizewithinthemothercell
throughtheday.
D)Inlateafternoon,finalpreparationsforendosporedormancy.
E)Endosporesmatureandremaindormantthroughoutmostofthe
night.
F)Justbeforesunrise,theendosporesgerminateandarereleased
frommothercelltorepeatthecycle.

19. Sporulation
StageI:Axialfilamentformationstage
•Inthisstagebacterialchromosomebecomethreadlikeknown
asaxialfilament.
•Axialfilamentsattachedtocytoplasmicmembraneby
mesosome.
•Elongationofcelltakeplaces.
•PHBAisthereservedfoodmaterialinBacillussppisutilized
insporulation.

21. StageIl:foresporeformation
•Asymmetriccelldivisionoccurs
•Cellmembraneformsseptumnearoneendwhichenclosesasmall
portionofDNAformingforespore
StageIll:engulfmentofforespore
•Mothercellmembranegrowaroundtheforesporeengulfingit.
•Foresporenowhastwomembranelayer.

22. StageIV:synthesisofexosporium
•Chromosomeofmothercelldisintegrates.
•Exosporiumsynthesisoccurs.
•ForesporestartsFormingprimodialcortexbetweentwomembrane.
•Dehydrationofcell.
StageV:synthesisofdipicolonicacid
•ProductionofSASPsanddipicolinicacidoccurs.
•Incorporationofcalciumionswithdipicolonicacidoccurforming
calciumdipicolonate.
•Furtherdehydrationofcytoplasm.
•Formationofcoatlayer.

23. Stage VI: maturation
•Maturation of endospore
Stage VII: release of endospore
•Cell lysis and release of endospore

24. Reference
•Brun, Y. & Shimkets, L. J.Prokaryotic Development(ASM Press, 2000).
•Sneath, P. H. Longevity of micro-organisms.Nature195, 643–646
(1962).
•"Microsporidia (Protozoa): A Handbook of Biology and Research
Techniques". Archived from the original on 26 June 2008. Retrieved8
July2007.. modares.ac.ir
•Johansson, Lönnell, Sundberg and Hylander (2014) Release thresholds
for moss spores: the importance of turbulence and sporophyte
length. Journal of Ecology, n/a-n/a.