the british empire ecology and famines in late 19th century central india
Spiny lobster ecology and exploitation in the south China sea region
... throughout the years due to the inconsistent supplies from the Philippines. On the other hand, spiny lobster landings in Kota Kinabalu were small, accounting for only 2% of the 2002 landings. There ... transported mainly from northern central provinces such as Hue, Da Nang, Quang Nam, Quang Ngai and Binh Dinh to meet the demand in southern central provinces, including Phu Yen, Khanh Hoa and Ninh ... Park and Pulau Tiga Park on the west coast and the Selingan Turtle Islands on the northeast. On the other Status of Spiny Lobster Resources in Sabah, MalaysiaRooney Biusing and Chio Fui LinDepartment...
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Childhood Health And Differences In Late-life Health Outcomes Between England And The United States ppt
... allergies in the United States and a 29% higher risk of respiratory problems in the US compared to England. Since England includes hay fever in allergies and the US in respiratory, the relative ... ‘explanation’ of the excess disease in the US arises from the inclusion in the model of the indicators of prevalence of the specific childhood illnesses themselves as opposed to the interactions of these ... country variations in social integration and social interactions explain differences in life expectancy in industrialized countries? In E. Crimmins, S. Preston, and B. Cohen (eds.), International...
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Victor McLaglen, the British Empire, and the Hollywood Raj: Myth, Film, and Reality pot
... and even sister Lily served by entertaining the troops with her singing. A propaganda poster circulated all over England featuring the “Fighting Macks,” with pictures of all the brothers in ... the brothers in uniform—including Fred, the brother who was killed— and also including Lily and their mother. One of the brothers enlisted at the age of thirteen, and another at fourteen. George ... uniforms were in fashion during the 1930s, and these riding clubs were just good opportunities to socialize and get drunk. There is certainly fodder for some closer scrutiny of the in- triguing issue...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 1 ppsx
... proposed in systems involving phenoloxidase enzymes. The deamination of amino acids, such as serine, phenylalanine, proline, methionine, and cysteine by birnessite, and the role of pyrogallol in influencing ... mechanical, including photocopying, microfilming, and recording, or by any informa-tion storage and retrieval system, without permission in writing from the publisher.Current printing (last digit):10987654321PRINTED ... in uencing their mineralizationhave been investigated (152,153). Nitrogen mineralization was inhibited by pyrogallol,whereas S mineralization of S-containing amino acids was not, except in the...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 2 pptx
... Currently,itisevidentthatmicroorganismsformcomplexmicrobialfoodwebsinallaquaticecosystems,andthattheiractivitiesandmetabolismsoftenaretightlycoupled and/ ormutuallyaffected(132,143,144).Therefore,itisnotsurprisingthatenzymaticpropertiesandactivitiesofdifferentcomponentscreatingthemicrobialfoodwebsinlakeecosystemshavedemonstratedcloserelationships.Severalreportshavedocumentedthestrongdependencyofbacterialsecondaryproductiononectoenzymeactivitiesofaquaticmicroorganisms(2–4,16,17,19,25,28,29,33,36,59).Thereoftenisasignificantcorrelationbetweenphytoplanktonprimaryproductionandactivitiesofdifferentectoenzymesinfreshwaterecosystems(25,28,29,33,52).Ourstudiesinlakesofdifferingdegreesofeutrophicationhaveshownmicrobialesteraseactivitytobepositivelycorrelatedtophytoplanktonprimaryproduction,bacterialsecondaryproduction,andconcentrationofdissolvedorganiccarbon(DOC)(Fig.13).Wehavefoundasignificantnegativerelationshipbetweenenzymeactivityandtheper-centageofphytoplanktonextracellularrelease(PER)ofphotosyntheticorganiccarboninthestudiedlakes.ThisnegativecorrelationbetweenPERandesteraseactivityindicatedthatenzymesynthesiswaspartiallyinhibitedinbacteriabylow-molecular-weightphoto-syntheticproductsofphytoplanktonthatwerereadilyutilizedbythesemicroheterotrophs:i.e.,catabolicrepressionofesterasesynthesiswasfoundinlakescharacterizedbyhighPERofphytoplankton(29,33).VIII.ECTOENZYMEACTIVITYANDLAKEWATEREUTROPHICATIONTheimportanceoforganicmatterasavariableforevaluatingthetrophicstatusoflakeshasbeenrecognizedsincethebeginningofthe20thcentury(145,146).Increasingconcen-trationsoforganicconstituentsinwaterarethedistinctindicatorsofacceleratedeutrophi-cationprocessesinmanylakes(147–149).OurstudiesclearlydemonstratedthatenzymeactivitiesweresignificantlypositivelyproportionaltoDOCcontentoflakes(Fig.13C).Asdescribedearlierinthischapter,severalmicrobialectoenzymesareresponsibleforrapidtransformationanddegradationofbothdissolvedorganicmatterandPOMinfresh-waterecosystems.Therefore,wehypothesizethatan‘‘enzymaticapproach’’canbeveryusefulinthestudiesoflakeeutrophication.Severalreportspointedoutthatmicrobialenzymaticactivitieswerecloselyrelatedtotheindicesofwatereutrophicationand/orthetrophicstatusofaquaticecosystems(25,27,29,31,33,38,52,58,62,78).Ourstudiesalongthetrophicgradientoflakes(fromoligo/mesotrophictohypereutrophiclakes[Fig.14A]supportourhypothesis(andtheassumptionsofothers)thatselectedenzymaticmicrobialactivitiesareverypracticalforarapidrecognitionofthecurrenttrophicstatusoflakes.Activitiesofalkalinephosphatase,esterase,andaminopeptidaseincreasedexponentiallyalongatrophicgradientandcorre-latedsignificantlywiththetrophicstateindexofthestudiedlakes(Fig.14B,C,D).Wealsofoundastrongrelationshipbetweenactivitiesofectoenzymesandphytoplanktonprimaryproductionintheselakes.RapidincreasesinectoenzymeactivitieswereobservedespeciallyinarangeofgraduallyeutrophiclakeswhenthevalueofCarlson’strophicstateindex(TSI)wasabove55(150)(Fig.14).Moreover, ... lakewater.Figures2Band2CshowthatectoenzymesynthesisinDOM-enrichedsampleswasnolongerrepressedwhentheconcentrationofthereadilyutilizablelowmolecular-weightmoleculesfellbelowacriticallevel,andpolymericsubstrateshadtobeusedtosupportthegrowthandmetabolismofbacteria.Similarinsituobservationsduringphyto-planktonbloomdevelopmentandbreakdownwerereportedfor-glucosidaseactivityineutrophicLakePluòsee(24),for-glucosidaseandaminopeptidaseactivitiesinmeso-trophicLakeSchoăhsee(25),andforlipaseactivityineutrophicLakeMikoajskie(40).Despitethewidespreadoccurrenceofcatabolicrepression,withtheexceptionofthoseforentericbacteria,themoleculardetailsoftherepressionarepoorlyunderstood.Somestudieshaveindicatedthatcyclicadenosinemonophosphate(cAMP),togetherwithitsreceptorprotein,mayplayacentralroleincontrolofcatabolicrepression(41,42).Usingtherepressionstrategyforectoenzymesynthesis,microorganismscanavoidthewastefulproductionofinducibleenzymes,whicharenotusefulwhentheirgrowthisnotlimitedbyUDOM(3,19,24,35).B.InhibitionofActivityItisimportanttoconsiderthattherepression/derepressionofanectoenzymenotbeequatedtothereversibleinhibitionofactivity.Evenifanectoenzymeissynthesized,itsactivitymaybeinhibitedbytheaccumulationoftheendproductorbyhighconcentrationsofthesubstrate(19).Twogeneraltypesofreversibleinhibitionareknown:competitiveandnoncompetitiveinhibition.Competitiveinhibitionoccurswhenaninhibitingcompoundisstructurallysimilartothenaturalsubstrateand,bymimicry,bindstotheenzyme.Indoingso,itcompeteswithanenzymesnaturalsubstratefortheactivesubstrate-bindingsite.Thehallmarkofcompetitiveinhibitionofmanyectoenzymes(e.g.,alkalinephosphatase,-glucosidase,aminopeptidase)isthatitdecreasestheafnityofanectoenzyme(anincreaseoftheapparentMichaelisconstantisobserved)forthesubstrateand,therefore,inhibitstheinitialvelocityofthereaction(Fig.3)(13,26,37).Competitiveinhibitionisreversibleandcanbeovercomebyincreasedsubstrateconcentration,andthereforethemaximumvelocity(Vmax)ofthereactionisunchanged(Fig.3A).Noncompetitive ... lakewater.Figures2Band2CshowthatectoenzymesynthesisinDOM-enrichedsampleswasnolongerrepressedwhentheconcentrationofthereadilyutilizablelowmolecular-weightmoleculesfellbelowacriticallevel,andpolymericsubstrateshadtobeusedtosupportthegrowthandmetabolismofbacteria.Similarinsituobservationsduringphyto-planktonbloomdevelopmentandbreakdownwerereportedfor-glucosidaseactivityineutrophicLakePluòsee(24),for-glucosidaseandaminopeptidaseactivitiesinmeso-trophicLakeSchoăhsee(25),andforlipaseactivityineutrophicLakeMikoajskie(40).Despitethewidespreadoccurrenceofcatabolicrepression,withtheexceptionofthoseforentericbacteria,themoleculardetailsoftherepressionarepoorlyunderstood.Somestudieshaveindicatedthatcyclicadenosinemonophosphate(cAMP),togetherwithitsreceptorprotein,mayplayacentralroleincontrolofcatabolicrepression(41,42).Usingtherepressionstrategyforectoenzymesynthesis,microorganismscanavoidthewastefulproductionofinducibleenzymes,whicharenotusefulwhentheirgrowthisnotlimitedbyUDOM(3,19,24,35).B.InhibitionofActivityItisimportanttoconsiderthattherepression/derepressionofanectoenzymenotbeequatedtothereversibleinhibitionofactivity.Evenifanectoenzymeissynthesized,itsactivitymaybeinhibitedbytheaccumulationoftheendproductorbyhighconcentrationsofthesubstrate(19).Twogeneraltypesofreversibleinhibitionareknown:competitiveandnoncompetitiveinhibition.Competitiveinhibitionoccurswhenaninhibitingcompoundisstructurallysimilartothenaturalsubstrateand,bymimicry,bindstotheenzyme.Indoingso,itcompeteswithanenzymesnaturalsubstratefortheactivesubstrate-bindingsite.Thehallmarkofcompetitiveinhibitionofmanyectoenzymes(e.g.,alkalinephosphatase,-glucosidase,aminopeptidase)isthatitdecreasestheafnityofanectoenzyme(anincreaseoftheapparentMichaelisconstantisobserved)forthesubstrateand,therefore,inhibitstheinitialvelocityofthereaction(Fig.3)(13,26,37).Competitiveinhibitionisreversibleandcanbeovercomebyincreasedsubstrateconcentration,andthereforethemaximumvelocity(Vmax)ofthereactionisunchanged(Fig.3A).Noncompetitive...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 3 pdf
... Investigationsofextracellularenzymesfrommarineanimalsandenzymesisolatedfromprokaryotesareconsideredonlyifaclearconnectiontomarineecologyisestablished.Thetermextracellularenzymesisusedthroughoutthischapter,whereasChrost(5)distin-guishesbetweenectoenzymesandextracellularenzymes.EctoenzymesaredenedbyChrost(5)andinChapter2asenzymeslocatedintheperiplasmicspaceorattachedtotheoutermembraneofthebacterialcell.Extracellularenzymesareenzymesfreelydis-solvedinthewaterorattachedtoparticlesotherthantheenzyme-synthesizingcell .In thischapter,however,thetermextracellularenzymesreferstobothectoenzymesandextracellularenzymes,unlessotherwisestated.EarlystudiesonthefateoforganicaggregatesanddissolvedpolymersintheseawerepresentedbyRiley(6),Walsh(7),andKhailovandFinenko(8).Overbeck(9)re-viewedtheearlystudiesonextracellularenzymeactivityintheaquaticenvironment.II.ECOLOGICALPRINCIPLESOFENZYMATICPATTERNSINTHESEAA.TheConceptoftheMicrobialLoopandtheRoleofExtracellularEnzymesThemicrobialloop(10)encompassesthecombinedactivitiesofautotrophicandheterotro-phiceukaryoticaswellasprokaryoticorganismssmallerthan20àm.Theseorgan-isms,representedbybacteria,nanoagellates,ciliates,andphototrophicprochlorophytes,aswellascyanobacteria,formafoodweboftheirown,looselyconnectedtothefoodwebofthelargergrazers.Ingeneral,thenutritionalbasisofthemicrobialfoodwebisprovidedbythepoolofdissolvedorganicmatter(DOM)andparticulateorganicmatter(POM).TheDOMpoolisapriorireservedforbacterialutilization,whereascompetitionwithmetazoansoccursforPOM.ThiscompetitionisdeterminedbythebacterialpotentialforenzymaticdissolutionofPOMontheonehandandthefeedingactivityofthemetazo-ansontheotherhand.Thebulkofboththedissolvedandparticulateresources,however,requiresenzymatichydrolysispriortouptakebybacteria(Fig.1).Thustheenzymaticactivitiesofbacteriainitiateorganiccarbon(C)remineralizationanddenethetypeandquantityofsubstrateavailabletothetotalmicrobialfoodweband,tocertainextent,alsotothetoppredatorsinthesystem.B.FreeandAttachedEnzymeActivityGenerally,extracellularenzymesmaybeboundtothecell(denedasectoenzymesbyChrost[5])orinthefreeandadsorbedstate(11,12).Mostofthetotalenzymeactivityinseawaterhasbeenfoundtobeassociatedwiththeparticlesizeclassdominatedbybacteria(0.2àm3àm)(13,14)(Table1).Dissolvedenzymes(15)andlargeparticles8 ... environment. In the salinity gradient between the Sac-ramento River and the central San Francisco Bay, increasing salinity was positively corre-lated with aminopeptidase activity and negatively correlated ... inthefreeform,andconsequentlyavailableforrapiduptake,remainsunknown.Thisadsorptionandtheconcurrentloweravailabilityforbacterialuptakemightcauseanunder-estimationoftheactualbacterialproductiononandinpolysaccharide-richmaterialsuchasmarinesnow(44),relativetobacterialenzymeactivity.ThecouplingbetweenhydrolysisanduptakeofDOMinparticle-associatedandfreebacteriaisstillnotfullyunderstood.Thereasonswhytheattachedbacteriabenetsolittlefromtheirstronghydrolyticactivities,iftherearenolimitingfactorsinterferingwiththeuptakeofenzymatichydrolysisproducts,areunknown.Thisfundamentaldiscrepancyshouldbemorethoroughlyinvestigatedinordertoimproveunderstandingofthebiogeo-chemicaluxoforganicmatterandtheroleofbacteriainthecyclingofDOMintheocean.Inanycase,itiswellacceptedthatparticledecomposition(45)contributessignicantlytothelossoforganicmaterialfromsettlingparticlesduringsinkingandthusdeterminestheefciencyofthebiologicalCpump(organicmattertransportfromtheseasurfacetotheseabed).D.EnvironmentalFactorsInuencingEnzymaticActivityThemagnitudeofthemainextracellularenzymeactivitiesinmarinewaterisfrequentlyintheorderaminopeptidasephosphatase-glucosidasechitobiaseesterase-glucosidase.However,exceptionsmayoccur,asobservedbyChristianandKarl(46)intheequatorialPacic,where-glucosidasewasaboutfourtimeshigherthanaminopep-tidase.Thissuggeststhattheremaybefactorsregulatingactivitiesonalargescale.How-ever,knowledgeofglobalregulatingfactorsisscarce.ChristianandKarl(47)foundthathistidineandphenylalanineinhibitedaminopeptidaseexpressioninAntarcticwaters.Like-wise,KimandLipscomb(48)suggestedthatmetalsmayberegulatingfactorsforproteases(leucineaminopeptidaseseemstobeprincipallyaZn2-dependentenzyme).ThiswasespeciallyduetoZn2(whichisrareinmarinewaters),butMn2,Co2,Fe2,andMg2mightalsoplayarole(4750).Inthesurfacelayeroftheocean,ultraviolet-Bradiationcanbeimportant,mainlythroughphotochemicaldegradationoftheextracellularenzymes(51,52).Withrespecttophosphataseactivity,theabundanceofinorganicPisregardedasaregulatingfactor,particularlyfortheP-limitedregionsintheoceans(5355).However,dissolvedorganicphosphorus(DOP)andparticulateorganicPalsoshouldbeconsidered(56).Furthermore,mechanismsofphosphataseregulationaredifferentforbacteriaandphytoplankton.WhilethephosphatasesofphytoplanktonseemtoberegulatedstrictlybyinorganicPconcentrations(49,5759),thismechanismisnotsoclearforbacterialphosphatases.ThelattermaytargetCandNratherthanPsupply,aspointedoutforthelimneticenvironmentbySiudaandGuăde(60)andforthedeepandC-limited,butphos-phate-replete,oceanbyHoppeandUllrich(61).Inanycase,regardlessofenvironmentalfactors,variationofspeciescompositionwithinthebacterialcommunitycansignicantlyinuencethedistributionofenzymeactivitiesinthesea(62,63).Theeffectsofenvironmentalfactorsonenzymeregulationarereectedbythediver-sityofextracellularenzymes,asexpressedinthepossiblerangesofKmandthepatternsofindividualcell-specicenzymepotentials(Table2,Table3).InformationontheKmvalues...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 4 potx
... Althoughthisstudyinvolvedtheuseofageneticallymodifiedmicrobe,themodifi-cationswerenotintendedtohaveafunctionalimpact;theywereinsertedasgeneticmark-ers.Asecondstudycomparingtheeffectofthesamegeneticallymarkedstraintothatofafunctionallymodifiedstrainshowedeffectsthataremoreinteresting(36).Theaimofthisworkwastodeterminetheimpactintherhizosphereofwildtypealongwithfunction-allyandnonfunctionallymodifiedPseudomonasfluorescensstrains.Thewild-typeF113straincarriedageneencodingtheproductionoftheantibiotic2,4-diacetylphloroglucinol(DAPG),usefulinplantdiseasecontrol,andwasmarkedwithalacZYgenecassette .The firstmodifiedstrainwasafunctionalmodificationofstrainF113withrepressedproductionofDAPG,creatingtheDAPGnegativestrainF113G22.Thesecondpairedcomparisonwasanonfunctionalmodificationofwild-type(unmarked)strainSBW25,constructedtocarrymarkergenesonly,creatingstrainSBW25EeZY-6KX.Significantperturbationswererecordedintheindigenousbacterialpopulationstruc-ture;theF113(DAPGϩ)straincausedashifttowardslower-growingcolonies(Kstrate-gists)comparedwiththenon-antibiotic-producingderivative(F113G22)andSBW25strains.TheDAPGϩstrainalsosignificantlyreduced,incomparisonwiththoseoftheotherinocula,thetotalPseudomonassp.populations,butdidnotaffectthetotalmicrobialpopulations.ThesurvivalofF113andF113G22wasanorderofmagnitudelowerthanthatoftheSBW25strains.TheDAPGϩstraincausedasignificantdecreaseintheshoot-to-rootratioincomparisontothatofthecontrolandotherinoculants,indicatingplantstress.F113increasedsoilalkalinephosphatase,phosphodiesterase,andarylsulfataseac-tivities(Table2)comparedtothoseofthecontrols.Theotherinoculareducedthesameenzyme ... beensteadyprogressinourunderstanding oftherhizosphereduringthelast 100yearsandanincreasingrealizationthatitcanhavemany in uencesoncrop productivity(Table1).However,therehasbeen a sudden increase in interest and ... Theresultsshowedlargedifferencesbetweenthe2daysofsamplinginsoilenzymeactivities(e.g.,alkalinephosphatase,Fig.2)andavailablesoilnutrients(e.g.,nitrate,Fig.3).Differenceswerefoundalsobetweenthevariousoilseedrapevarietieswithmostsoilenzymesmeasuredandwiththeavailablesoilnutrients.However,therewaslittlediffer-encebetweentheenzymeactivitiesintherhizosphereoftheGMandnon-GMplants.Themajorfactorinfluencingtheenzymeactivitiesandsoilnutrientsbetweenthetwosamplingdayswasthesoilmoisturecontent,whichwasincreasedbyovernightrain.Therefore,inthisfieldtrial,thedifferencesbetweensoilenzymeactivitieswerenotattrib-utabletoplantgeneticmodification,buttoenvironmentalvariationandtodifferencesinplantvariety.V.CONCLUSIONSClearlyenzymeactivitiesareusefulindeterminingperturbationsinthesoilenvironmentbroughtaboutbychangesinagriculturalpractices,theuseofagrochemicals,pollutionevents,ortheexploitationofgeneticallymodifiedorganisms.Biocontrolofpestsanddiseasesisameansbywhichenzymefunctionhasbeenexploited(43),butthereisevengreateropportunitytomonitorandmanipulateenzymesasgenerationsofplantnutrients,plant-growth-promotingagents,soilstructurestimulants,andbioremediationcatalysts.Althoughbioremediationhashadlessattentionthanbiocontrol,thepotentialforexploitationisenormous(44).Mostresearchhasbeenfocusedonmicrobialinoculants(bioaugmentation),butitisequallyrelevanttoconsiderhowtooptimizethefunctionoftheindigenousorganisms(biostimulation).Phytoremediation,byplantrootsthemselvesorassociatedmicrobiota(rhizoremediation),isbecominganincreasinglyinterestingcleanupsolutionforsoils.Mostattentionhasbeenpaidtoheavymetaldecontamination ,and whereasthereisinevitablysomeenzymeinvolvement,littlehasbeencharacterized.How-ever,rhizospheremicroorganismsproduceenzymesthathavethecapacitytocatabolizeawiderangeoforganicpollutants.MicrobialdehalogenationisdescribedindetailinChapters1 8and1 9,butofspecialinterestarehydrogencyanideandothernitriles.Notonly...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 5 ppt
... delivered to the apoplast by the host cell. Thensucrose is hydrolyzed in the apoplastic interface by an acid invertase of plant origin, and the resulting hexoses are absorbed by the fungus (59), and ... 4)-glucans(53).Xyloglucansare-1,4-glucanswithsidechainsthatcanhydrogenbondtocellulosemicrobrils,cross-linkingthemandrestrainingcellexpansion.Inadditiontoastructuralrole,xyloglucanscanbehydrolyzedbyhydrolyticenzymes,andtheoligosac-charidesproducedmayactassignalmolecules(15,54).Theplantcellwallcontainsglucanasesandglycosidasesthathydrolyzexyloglucanintomonosaccharides.Endo--1,4-glucanaseactivityisresponsiblefortherststepofdegradationwherebythexyloglucanisendohydrolyzedintolargefragmentsandexo-1,4-glucanaseactivityliberateslow-molecular-weightfractionsfromtheendsoflongpolysac-charidechains(41).TheproductionofhemicellulolyticenzymeshasbeenobservednotonlyinparasitesbutalsoinmutualisticmicroorganismssuchasRhizobiumspecies(24)andarbuscularmycorrhiza(28).Endoxyloglucanaseactivityincreasesduringgrowthanddevelopmentofroots(55).Thisactivitywasconsistentlyhigheratthebeginningofcolonizationandthelogarithmicstageofdevelopmentofmycorrhizalfungus(55).Theincreaseinfungalstructuresthatpenetratethecellwallduringthelogarithmicstageofrootcolonizationmayexplaintheincreaseinthedifferentactivitiesatthistime(56).Theevolutionofendoxyloglucanaseactivitiesinplantsparalleledthechangesintheexternalmycelium.Therewere,however,bandsofxyloglucanaseactivityinnonmycorrhizalrootsthatwereabsentinmycorrhizalroots;thatmaysuggestqualitativeinhibitionbythefungusofsomeplantactivity.Inhibi-tionofplantproteinsynthesisbyAMfungihasbeenobservedinseveralplantAMfungiassociations(57,58).III.ENZYMESINTHEPHYSIOLOGYOFTHEASSOCIATIONA.PhosphorusUptakeItnowisestablishedthatmycorrhizalcolonizationcanenhancetheuptakefromsoilofsolubleinorganicPbyplantroots(59).Althoughparticularlyimportantinlow-Psoils,anincreasedrateofPuptakecanoccuroverarangeofsoilPlevelsevenwhenmycorrhizalgrowthresponsesnolongeroccur.TheenhancedPuptakebymycorrhizalplantsismostlikelytheresultoftheexternalfungalhyphaesactingasanextensionoftherootsystem,therebyprovidingamoreefcient(moreextensiveandbetterdistributed)absorbingsur-faceforuptakeofnutrientsfromthesoilandfortranslocationtothehostroot(60).ExternalhyphaeofAMfungimustabsorborthophosphate(Pi)byactivetransport(59,61).TheyhaveanactiveH-ATPaseintheplasmamembranethatwouldbecapableofgeneratingtherequiredproton-motiveforcetodriveH-phosphatecotransport,andPcertainlyisaccumulatedtohighconcentration(62).Polyphosphate(poly-P)isamajorPreserveinmanyfungianditaccumulatesinvacuolesofAMfungi(63).Transferofmycorrhizalrootsfromlow-tohigh-Pmediaresultsinarapidaccumulationofpoly-P(64).Enzymesofpoly-Psynthesishavebeenfoundinmycorrhizaltissue(63,65).Polyphosphatekinase,whichcatalyzesthetransferoftheterminalphosphatefromATPtopoly-P,wasdetectedinbothexternalhyphaeandmycorrhizalrootsbutnotinuninfectedroots,indicatingthatpoly-Pcanbesynthesizedonlybythefungalcomponentofthemycorrhiza.AlthoughitnowseemslikelythatPistranslocatedbyprotoplasmicstreamingintotheintraradicalhyphaeaspoly-P(66),littleisyetknownofthebiochemicalmechanismsinvolved.Thetransportthroughthehyphaeandunloadingstepswithinthearbusculemaybelinkedtopoly-Pmetabolism(Fig.2).Highproportionoflong-chainpoly-PtototalCopyright ... ThepatternsofenzymeactivityandmRNAaccumulationsuggestthatchitinases and -1,3-glucanasesmightbepartoftheearlydefenseresponsebytheplanttotheinvad-ingfungus,whichisthensuppressedassymbioticinteractionsdevelop.Inthiscontext,planthydrolasesmaybeinvolvedintheregulationofAMdevelopment.Nevertheless,someexperimentaldatarevealedthatitisnotlikelythatplantchitinasesandglucanasesareessentialtothecontrolofthegrowthofAMfungi.TransgenicplantsconstitutivelyexpressinghighlevelsofdifferentacidicformsoftobaccoPRs(includingchitinasesandβ-1,3-glucanases)becamenormallycolonizedbytheAMfungi(122,123).Thefactthatchitinasesandβ-1,3-glucanasesinducedbytheAMsymbioticfungiorbyconstitutivegeneexpression,donotpreventrootcolonizationsuggeststhattheyareineffectiveincontrollingfungaldevelopment.ThelowenzymaticaffinityforAMfungalcomponentsorinaccessibilityoftheseenzymestofungalcellwallcomponentsmaycausethisineffec-tiveness(112).Conversely,specificacidicformsofchitinaseandβ-1,3-glucanaseareactivatedinseveralplantscolonizedbyAMfungi.Thesesymbiotic,specificisoenzymeshavebeenreportedinpea(124),tobacco(118),andtomato(125–127)rootsandaredifferentfrompathogen-inducedisoformsorconstitutiveenzymes.Inaddition,newchitosanaseisoformshavebeenshowninpea(128)andtomato(126).Chitosanasesarehydrolyticenzymesactingonchitosan,aderivativepartiallyorfullydeacetylatedofchitin(129).Interestingly,themycorrhizal-relatedchitinaseisoformdescribedintomato-colonizedrootsappearedtodisplaychitosanaseactivity.Thisbifunctionalcharacterwasnotfoundfortheconstitutiveenzymes,orinPhytophthorasp.–inducedchitinases(126).Mycorrhizal-specificplantchi-tinasesarenotactiveinpathogen-infectedroots(118,124–125)orinRhizobiumsp.legumesymbiosis(130),indicatingadifferentialinductionandfunction.AlthoughtheprecisefunctionofplanthydrolaseactivitiesintheestablishmentofAMsymbioticinteractionisstillunclear,theirstimulationseemstobeakeypointinthemechanismofrecognitionandsignalingbetweenplantrootsandAMfungi.AregulatoryroleoftheseenzymesduringestablishmentofAMandotherrootsymbiosishasbeenproposed.Stimulationofspecificplantchitinaseshasbeenreportedinsoybean/Rhizobiumsp.(131)andectomycorrhiza(132).Ithasbeenpostulatedthatchitinasesmaybeinvolvedintherecognitionoftherhizobialnodulationsignalsand,thus,intheregulationofthenodulationprocess(133).Thedatasuggestaspecificrolefortheseenzymes,onethatcouldberelatedintheAMsymbiosistothedetection,modification ,and/ orreleaseofchitinorchitosanoligomersfromthefungalcellwallthatcanactassignalingcompoundsduringthedevelopmentofAM(Fig.3).Inthisprocessofsignalexchange,themodulationof...
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7Microbial Enzymes in the Biocontrol of Plant Pathogens and aEnzymes in the Environment: Activity, Ecology and Applications - Chapter 7PestsLeonid Chernin and Ilan ChetThe ppt
... 2.Glucanasesβ-1,3-glucan,orlaminarin,isapolymerofd-glucoseinaβ-1,3configuration,arrangedashelicalcoils.Fungalcellwallscontainmorethan60%laminarin.Whereaschitinisarrangedinregularlyorderedlayers,laminarinfibrilsarearrangedinanamorphicmanner.Therearechemicalbondsbetweenthelaminarinandchitin,andtogethertheyformacomplexnetofglucanandGlcNAcoligomers(103).Laminarinishydrolyzedmainlybyβ-1,3-glucanases,alsoknownaslaminarinases.Theseenzymes,describedinfungi,bacteria,actinomycetes,algae,mollusks,andhigherplants,arefurtherclassifiedasexo-andendo-β-glucanases.Exo-β-1,3-glucanases(β-1,3-glucanglucanohydrolase,[EC3.2.1.58])hy-drolyzelaminarinbysequentiallycleavingglucoseresiduesfromthenonreducingendsofpolymersoroligomers.Consequently,thesolehydrolysisproductsareglucosemonomers.Endo-β-1,3-glucanases(β-1,3-glucanglucanohydrolase[EC3.2.1.6orEC3.2.1.39])cleaveβ-1,3linkagesatrandomsitesalongthepolysaccharidechain,releasingsmalleroligosaccharides.Bothenzymetypesarenecessaryforthefulldigestionoflaminarin(104).Theseenzymeshaveseveralfunctionsinfungiincludingnutritioninsaprotropism,mobilizationofβ-glucansunderconditionsofC-andenergy-sourceexhaustion,andaphysiologicalroleinmorphogeneticprocessesduringfungaldevelopmentanddifferentia-tion(105).GlucanaseshavebeensuggestedasanothergroupofkeyenzymesinvolvedinthemycoparasitismofGliocladiumandTrichodermaspp.againstfungalplantpathogens(Ta-ble1).Thesubstrateoftheseenzymes,β-1,3-glucan,isoneofthemajorcomponentsoffungal ... againstplant-pathogenic fungi. The free enzyme can be introduced into the irrigation water orincorporated into the seed coating to protect germinating seedlings. However, the activityof free enzymes in the soil ... expression in T. harzianum is regulated by (i) bindingof Cre1 to two single sites in the ech42 promoter, (ii) binding of a ‘‘mycoparasitic’’protein–protein complex to the ech42 promoter near the Cre1...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 8 potx
... affecting the efficiency of interaction of the substrate and enzyme molecules. In other words, a portion of the enzyme molecules existing in the field soil may not be actively engaged in catalyzing their ... enzymes, laccase and tyrosinase. The potential role of these enzymes in the humification of anilinic and phenolic compounds and reduction of their bioavilability with the passage of time (aging) is sufficient ... invertase, and protease have been found to be stimulated in the detritosphere (the soil litter interphase) (67). In another study, xylanase and invertase levels were ele-vated in the soil particle-size...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 9 potx
... wererepressedbyaddedN;formapleandoak,theseactivitiesincreased.Theresultssuggestedthatwhiterotfungi,whichproduceligninasesinresponsetolowNavailability,weredisplacedbysupplementalN,slowingthedecompositionofrecalcitrantlitter.HenriksenandBreland(27)alsofocusedontheroleofNinthedecompositionprocess.Usingamicrocosmsystemofwheatstrawandsoil,theyfoundthatcarbonminer-alization,fungalbiomass,andactivitiesofcellulolyticandhemicellulolyticenzymesde-creasedwithNavailability.Intheareaofcomparativeecosystemstudies,Sinsabaughetal.(62,63)followedmassloss,NandPimmobilization,andactivityof11typesofextracellularenzymesforbirchsticks(Betulapapyfera)decomposingateightupland,riparian,andloticsitesoverarst-orderwatershed.Masslossratesamongsitesvariedbyafactorof5andwerecorrelatedwithlignocellulaseactivities.Incontrast,relationshipsbetweenmasslossandactivitiesofacidphosphataseand-1,4-N-acetylglucosaminidasevariedwidelyamongsites.TheserelationshipsalongwithanalysesoftheNandPcontentofthestickssuggestedthatdifferencesinmasslossratesamongsitesweretiedtodifferencesinnutrientavail-ability.Inanotherexperiment,litterbagscontainingsenescentleavesofAgeratumconi-zoidesandMallotusphilippinensiswereplacedontheoorofayoungtropicalforestsiteinnortheastIndia(38).OtherlitterbagscontainingleavesofHolarrhenaantidysentericaandVitexglabratawereplacedatamaturetropicalforestsite.Athigher-elevationsubtrop-icalsites,litterbagscontainingPinuskesiyaandMyricaesculentaleaveswereplacedinayoungforestandbagscontainingPinuskesiyaandAlnusnepalensisleaveswereplacedinamatureforest.Sampleswereanalyzedformassloss,bacterialandfungalnumbers,cellulosecontent,Ncontent,solublesugarcontent,andactivitiesofcellulase,amylase,andinvertase.Cellulaseandamylaseactivitieswerecorrelatedwithmicrobialnumbers.Invertaseactivitycorrelatedwithsolublesugarcontent.Enzymeactivitiesandmasslossrateswerehigheratthelowerelevationsitesbutwerenotrelatedtostandage.Inasimilarstudy,thedecompositionofPinuskesiyaandAlnusnepalensisatadisturbedroadsideforestsitewascomparedwiththatatanundisturbedsite(30).Againcellulaseandamylaseactivitieswerecorrelatedwithmicrobialnumbers,whereasinvertaseactivitywaslinkedtosolublesugars.DillyandMunch(18)studiedenzymeactivitiesandmicrobialrespirationforAlnusglutinosa(blackalder)leavesdecomposingatwetanddrysiteswithinafenforest.Masslossratesweremorethantwiceasfastatthewetsite.Microbialbiomassandrespirationdecreasedovertime(16to2.3àmolg1h1),buttheefciencyofCutilizationincreased.Thesetrendswereparalleledbydecreasing-glucosidaseactivityandincreasingproteaseactivity.III.COMPARATIVEANALYSESInthecontextofthesuccessionalloopmodel(Fig.1),therearethreedimensionsforcomparing ... wererepressedbyaddedN;formapleandoak,theseactivitiesincreased.Theresultssuggestedthatwhiterotfungi,whichproduceligninasesinresponsetolowNavailability,weredisplacedbysupplementalN,slowingthedecompositionofrecalcitrantlitter.HenriksenandBreland(27)alsofocusedontheroleofNinthedecompositionprocess.Usingamicrocosmsystemofwheatstrawandsoil,theyfoundthatcarbonminer-alization,fungalbiomass,andactivitiesofcellulolyticandhemicellulolyticenzymesde-creasedwithNavailability.Intheareaofcomparativeecosystemstudies,Sinsabaughetal.(62,63)followedmassloss,NandPimmobilization,andactivityof11typesofextracellularenzymesforbirchsticks(Betulapapyfera)decomposingateightupland,riparian,andloticsitesoverarst-orderwatershed.Masslossratesamongsitesvariedbyafactorof5andwerecorrelatedwithlignocellulaseactivities.Incontrast,relationshipsbetweenmasslossandactivitiesofacidphosphataseand-1,4-N-acetylglucosaminidasevariedwidelyamongsites.TheserelationshipsalongwithanalysesoftheNandPcontentofthestickssuggestedthatdifferencesinmasslossratesamongsitesweretiedtodifferencesinnutrientavail-ability.Inanotherexperiment,litterbagscontainingsenescentleavesofAgeratumconi-zoidesandMallotusphilippinensiswereplacedontheoorofayoungtropicalforestsiteinnortheastIndia(38).OtherlitterbagscontainingleavesofHolarrhenaantidysentericaandVitexglabratawereplacedatamaturetropicalforestsite.Athigher-elevationsubtrop-icalsites,litterbagscontainingPinuskesiyaandMyricaesculentaleaveswereplacedinayoungforestandbagscontainingPinuskesiyaandAlnusnepalensisleaveswereplacedinamatureforest.Sampleswereanalyzedformassloss,bacterialandfungalnumbers,cellulosecontent,Ncontent,solublesugarcontent,andactivitiesofcellulase,amylase,andinvertase.Cellulaseandamylaseactivitieswerecorrelatedwithmicrobialnumbers.Invertaseactivitycorrelatedwithsolublesugarcontent.Enzymeactivitiesandmasslossrateswerehigheratthelowerelevationsitesbutwerenotrelatedtostandage.Inasimilarstudy,thedecompositionofPinuskesiyaandAlnusnepalensisatadisturbedroadsideforestsitewascomparedwiththatatanundisturbedsite(30).Againcellulaseandamylaseactivitieswerecorrelatedwithmicrobialnumbers,whereasinvertaseactivitywaslinkedtosolublesugars.DillyandMunch(18)studiedenzymeactivitiesandmicrobialrespirationforAlnusglutinosa(blackalder)leavesdecomposingatwetanddrysiteswithinafenforest.Masslossratesweremorethantwiceasfastatthewetsite.Microbialbiomassandrespirationdecreasedovertime(16to2.3àmolg1h1),buttheefciencyofCutilizationincreased.Thesetrendswereparalleledbydecreasing-glucosidaseactivityandincreasingproteaseactivity.III.COMPARATIVEANALYSESInthecontextofthesuccessionalloopmodel(Fig.1),therearethreedimensionsforcomparing ... acidanalysis), and activities of xylanase, laminarinase, phosphatase, urease, and chitinase.They found a correspondence between functional diversity and structural diversity, bothpeaking in spring. Others...
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Enzymes in the Environment: Activity, Ecology and Applications - Chapter 10 docx
... enzymes in the upper part of the profile couldbe due to the presence of fungi (chitin in the cell walls) and arthropods (chitin in the exoskeleton) serving as substrates.Enzyme determination using ... the years; these include vanilin, indulin, ferrulic acid, and, most importantly,14C-labeled synthetic lignins. Various fungal enzymes are involved in lignin degradation, including lignin peroxidase, ... soils and horizons; for determining the effects of pollution and changes in climate and land use; and for using biomass data in decomposition models (13). The mycelium is often well hidden in soil...
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