NUTRITION IN BACTERIA.pdf

This presentation gives the bird's eye view of bacterial nutrition along with some other issues required to understand bacterial diversity as far as nutrition is concerned.

1. NUTRITION IN
BACTERIA
By
Dr. N. Sannigrahi,
Associate Professor,
Department of Botany,
Nistarini college,
Purulia,
D.B. Road, Purulia (
W.B)
India, 723101

2. Allformsoflife,frommicrobestohumanbeings,sharecertainnutritional
requirementsforgrowthandnormalfunctioning.Thefollowing
observationsholdgoodforthisattributes-
Allorganismsrequiresourceofenergyeitherfromsolarenergy
(Phototrophs)orchemicalcompounds(Chemotrophs),
Requiredsourceofelectronsformetabolism,eitherreducedinorganic
compoundsaselectrondonors(Lithotrops)ororganiccompounds(
Organotrops-ChemoorganotroipsorPhotoorganotrops),
Requirecarbonasautotrophsorheterotrophs,\
RequireNitrogenfordiversecompounds,
Requireoxygen,sulpherandPhosphorousaskeyelementstoperform
differentmetabolicactivities,
DifferenttraceelementslikeZn,Mn,Cu,Fe,Mg,Mo,B,Coascofactors
formetabolicissues,
Inadditiontovitaminsorvitaminlikecompoundsandwater

3. Bacteriaareprokaryoticorganismsthatrequirenutrientsandenergyfor
theirgrowthanddevelopmentlikeotherlivingorganisms.Theyrequire
carbon,hydrogen,oxygen,nitrogen,metalsandwaterfortheirbiochemical
processes.
Inorganicnutrientsgettheirinorganicnutrientsfromenvironment.
Microbesdifferverymuchwithrespecttotheirorganicrequirements,
Somecanmanufacturetheirfoodfrominorganicsources,
Someotherabsorbtheirorganicnutrientsfromenvironment,
Onthebasisoftheirenergysourceandthecarbon,bacteriaaredividedinto
twomajorclasses:autotrophsandheterotrophs.
Requiredforstructuralcomponentsofcelllikecellmembrane,
protoplasmiccomponents,
Synthesisofbio-moleculeslikeprotein,lipid,nucleicacidsetc,
Toassistcompletegrowth,
Tocatalyzingenzymeactivities

4. CARBON-Servesasbackboneoftheorganiccompoundsavailabletothe
organismsfrompreexistingorganiccompoundsinthehabitatorcellular
metabolisms,
OXYGEN-Availabletotheorganismsfromwater,atmosphereandotherorganic
compounds,
NITROGEN-14%ofthedryweight,constituentofaminoacids,nucleicacids,
nucleotides,proteinsororganisms,availablefromammonia,nitrates,atmospheric
nitrogenandothernitrogenouscompounds,
HYDROGEN-8%ofthedryweightastheorganiccompoundsofcellandcell
water,actaselectrondonorsofvariousorganisms,gethydrogenfromwaterand
otherorganiccompounds,
PHOSPHOROUS -Essentialforthesynthesisofnucleicacids,phospholipids,
nucleotides,cofactors,ATP,someproteinsandothercellularcomponents,3%of
thedryweightcomesfrominorganicphosphates,
SULPHER-Requiredforthesynthesisofmethionine,biotin,thiamine,sulpher
containingproteins,1%ofthedryweight,availablefromH2s,elementalsulpher
andorganicsulphercompounds,
K,Mg,Ca,Fe-ascellularcationsandcofactorsforcertainenzymaticfunctions,K
helpsintransportmechanisms,Fefromthecomponentsofcytochromesenzymes
andnonhemeproteins

6. Transportofnutrientstakeplaceby-
I.Passiveprocess–withoutexpenditureofenergy,
A.Passivediffusion-fromhigherconc.Tolowerconc.asperrulewiththe
largeconcentrationgradient,
B.Facilitateddiffusion-Bythepresenceofcarriermoleculelikepermease,
allowsspecificmoleculestodiffuseintothecellthatotherwisewouldnot
havetakenup,withoutenergy,bytheconcentrationgradient
II.Activeprocess-Atthecostofenergyeitherby
Symport-linkedtransportoftwosubstancesinthesamedirection,
Antiport-limitedtransportoftwosubstancestooppositedirection
III.Bulkuptake-ingestionwhenthecellextendspseudopodiaaroundlarge
moleculestrappingthemindigestivevacuoleseitherbyphagocytosis
(solid)orpinocytosis(liquid).
IV.Grouptranslocation-moleculesaremodifiedastheyaretransported
acrossthemembrane,complexmechanismwithcytoplasm&membrane
enzymesinvolved,helpsintransportofsugarusingPEPasphosphate
donor.

10. NutritionalTypesofBacteria
Theclassificationofbacteriabasedonnutritionisasfollows:
Autotrophs
Organismsthatobtaincarbonfromcarbondioxideanduselightenergyor
inorganicchemicalcompoundstoproducecomplexorganiccompoundsare
knownasautotrophs.Thesearebacteriathatcansynthesizetheirownfood
frominorganiccompounds.
Autotrophicbacteriaarefurtherclassifiedintotwo:
Photoautotroph
PhotoautotrophicbacteriauseCO
2astheircarbonsourcetoconvertitinto
carbohydratesinthepresenceofsunlight.Thesebacteriahave
bacteriochlorophyllandbacterioviridinpigmentsintheirphotosystems.
Example:cyanobacteria,purplesulphurbacteriaandgreensulphur
bacteria.
Note:GreensulphurbacteriauseH
2Sasthehydrogendonor.

11. Chemoautotrophs
Chemoautotrophsareorganismsthatuseinorganicsourcestosynthesize
organiccompoundsintheabsenceoflight.Thesebacterialackany
pigmentsandcarryoutonlythedarkphaseofphotosynthesis.Example:
sulphurbacteriathatoxidizeelementalsulphurtogainenergy,Hydromonas
(hydrogenbacteria)thatconverthydrogenintowater,ironbacteriathat
obtainenergybyoxidizingdissolvedferrousoxides,methanogensand
nitrifyingbacteria.
Heterotrophs
Heterotrophsareorganismsthatcannotmaketheirownfoodbutinstead
obtainnutritionfromotherorganicsourcesthatmaybelivingordead.
Heterotrophscanbedividedintotwo:
Photoheterotrophs
Photoheterotrophicbacteriaarethosethatuselightastheirsourceof
energybutcannotusecarbondioxideasthecarbonsource.Insteadthey
obtainnutritionfromorganiccompoundsfoundintheenvironmentsuchas
alcohols,carbohydratesandfattyacids.Examples:purplenon-sulphur
bacteria,heliobacteriaandgreennon-sulphurbacteria.

12. Chemoheterotrophs:Chemoheterotrophsareorganismsthatderivetheir
energyaswellastheircarbonsourcefromorganiccompoundssuchas
carbohydratesandlipids.Example:saprophyticbacteria
(i)Parasitic:Thesebacteriaobtaintheirfoodfromlivinghostsonwhich
thesegrow.Parasiteswhichcausediseasesareknownaspathogense.g.,
Clostridium,Mycobacteriumetc.
ii)Saprophytic:Thesebacteriaobtaintheirfoodfromdeadandorganic
remainslikefruits,vegetables,leaves,meat,faeces,corpsesandothernon-
livingproducts.Theanaerobicbreakdownofcarbohydratesisfermentation
whilethatofproteinsiscalledputrefaction,e.g.,Putrefyingbacterialike
Bacillusmycoides,B.ramosusetc.
(iii)Symbiotic:Thesebacterialiveincloseassociationwithorgansof
otherorganisms(higherplantsandanimals)insuchawaythatboththe
concernedorganismreceivemutualbenefitfromthisassociation.Thisis
calledsymbiosisfore.g.,Rhizobiumleguminosarumintherootnodulesof
theleguminousplants.

13. Thisbacteriafixfreeatmosphericnitrogenintonitrogenouscompounds
whichareutilizedbytheplants.Inreturn,theplantprovidesnutrientsand
protectiontothebacteria.Inthestomachofthecowsandgoatsbacteria
digestcelluloseenablingtheseanimalstofeedongrass.Ourownintestine
containsanumberofharmlessbacteriae.g.,Escherichiacoli.
Itisapparentthattogrowbacteriasuccessfully,theabovetypeofthe
nutritionalrequirementsalongwiththediversetypeofthechoicesof
nutritionselectedbythebacteriafortheirgrowthandmultiplication.
Theartificialenvironmentneedsmediacompositionasperthebasic
ingredientsalongwithotherselectivesubstancesrequiredinthisregard,
Theenvironmentalparameterslikeoxygen,pH,temperatureandother
parametersarealsorequiredinthisregardforthebacterialpleasure.
Thus,itcanbeconcludedthatlikethehigherorganisms,bacteriaarenot
exceptionaloneinthisregardfortheirgrowth&development.

14. References:
Google for images
Microbiology & Phycology -Mishra & Dash
Brook Microbiology of Microorganisms-Madigan, Martinko,
Bender, Buckley & Stahl,
A Textbook of Microbiology-Chakraborty
Microbiology-Pelzer Jr., Chan & Krieg,
Different WebPages to enrich content.
Disclaimer:This PPT has been designed to enrich the open source
of learning. The author does not claim any kind of financial
pleasure