Upload
karthikeyan-shanmugam
View
8
Download
3
Embed Size (px)
DESCRIPTION
Hindu Scitech compilation
Citation preview
xaam.in http://www.xaam.in/2015/01/thehinduscienceandtechnology_29.html
TheHinduScienceAndTechnology(Thursdayspecial)articlescompilation
BuildingamolecularlegotofightmalariaandTB
Weneednewermethodsanddrugstokillthesepathogensmycobacteriumtuberculosisandplasmodiumfalciparum.
Tuberculosisandmalariaarethemostprevalentdiseasesthatkillmankindtoday.Currentlyavailablemethodsanddrugsareunabletostemthetide.Thisiswhygovernments,theGatesFoundation,WellcomeTrustandothersareinvestinglargesumstofindwaystostoporreducetheirprevalenceandtohelpdevelopnewmethodsandmoleculesasdrugs.
Thebattlebetweenthesepathogensandpeopleisacolossalone.Weneednewermethodsanddrugstokillthesepathogensmycobacteriumtuberculosis(Mtb)andplasmodiumfalciparum(andp.vivax).Andthebattleisliterallymindovermutations.Thehumanmindhascontinuouslyattemptedtodevisenovelmoleculesasdrugssuchasthefluoroquinolones,rifampicin,andartemisinin.Ontheotherside,eventhoughlargenumbersarekilledbythesedrugs,anoccasionaloutlierbugwhichdoesnotsuccumbtothedrug,thankstoarandomerrorinitsgeneticsequence(mutation),survivesandreproducesmoreofitself.Prettysoon,thisdrugresistantmutantpropagatestobecomethemainstrain,andthethoughtfullycrafteddrugisnolongereffective.Itisalsoabattleoftimescale.Whilewetakeyearstocreateeffectivedrugsanddistributethemforeverydayuse,microbestakejusthoursanddaystoreproduceandpropagatetobillionsinmonths.WhiletheTBstrainsofjustafewyearsagocouldnotsurviverifampicin(whichblocksthebugsRNAmakingmachinery,thusstoppingitsgrowth),todaysstrainshaveevolvedtofindalternatepathstocarryon.Similarly,withmalaria,whileartemisinin(thewonderdrugofyesteryears)actsonthebloodingestedbytheparasite,burnsitthroughoxidativestressandthuskillsthepathogen,todaysplasmodiumstrainshaveevolvedwithamechanismtodetoxifythisoxidativestressandbecomeartemisininresistant.Wearethusfacinghostsofmultidrugresistantpathogensinfectingus.Itisagainstthisbackgroundthatsomenewideashavecomeaboutwhichcouldhopefullysidestepthisresistanceissue.Notethattheearlierdrugsactonthepathogenafteritentersthetargetcellsinthebodybeitblood,liverorelsewhereandusethehostmachinerytogrowandmultiply.Whatifwestoptheentryitself?Wouldthatwouldstopthepathogenonitstrackandthusstoptheinfection?Somemindshavebeenthinkingsuchathoughtandcarriedoutresearchtowardsthisidea.Themostrecentone,publishedtwoweeksago(onPongalDay,1412015)inthejournalNatureCommunicationsisbyDrs.AnandRanganathan,PawanMalhotraandtheircolleaguesattheInternationalCentreforGeneticEngineeringandBiotechnology,andAllIndiaInstituteofMedicalSciences,bothinNewDelhi,India(6:6049/DOI:10.1038/ncomms7049/www.nature.com/naurecommunications).Thegrouphascapitalisedontheideathatsomemoleculesonthesurfaceofcells,termedintercellularadhesionmolecules(ICAMs,whicharepartoftheimmunoglobulinsuperfamily)actassentries,regulatingtheentryandadhesionofothercells,nativeorforeign.ThemoleculeICAM1isseenonvariouscelltypes,notablymacrophages(atypeofwhitebloodcellsthatingestsforeignmaterial).ICAM4,ontheotherhand,isrestrictedtothesurfaceofredbloodcells.OnecanthusseethatwhileICAM1wouldregulatetheentryandinvasionbyMtbintomacrophages,ICAM4wouldregulatemalariaparasiteslikewise.Ifonlywecoulddiscoverorinventadecoymoleculethatsitsatthisgate,blockingtheentryofMtb,wecouldovercomeinfectionbythisdeadlypathogen.Likewise,ifwecanblocktheentryandinvasionbyplasmodiumintoredbloodcells,usingadecoymoleculethatbindstoICAM4,wewouldhaveadrug
http://www.xaam.in/http://www.xaam.in/2015/01/the-hindu-science-and-technology_29.html
againstmalaria.Notetoothatthesedecoysdonotworkaftertheevent(likethedrugsabovedo),butdenytheunwelcomevisitorthevisatoenteranddodamage.MolecularLegopieces
Tothisend,theDelhigroupdecidedtoworkonanovelideathatDrAnandRanganathanhadcomeupwithadecadeago,whichhecallsthecodonshufflingmethodofmakingsmallproteinmolecules(seeJ.Biol.Chem.280:23605,2005).ThisinvolvestheuseofaseriesofproperlychosenDNABricks,each6baseslong(twocodonslong,forthecognosenti),linkingthemtogethertovariouslengthstoproducealibraryofpeptide/proteinmoleculesofvarioussizesandpredictableshapes.Thisisaneasyandcraftyway,usingtheseDNAbricks,tomakeawholehostofminiproteinsaspotentialdrugs.
TheynexttestedtoseewhichmembersoftheabovelibraryinteractwithICAM1andwithICAM4.Happilyenough,alargepeptidenamedM5wasfoundtobindstronglytobothICAM1andICAM4.TheynextchallengedMtbwithmacrophagesinthepresenceofM5.WhileMtbinfectscontrolsamplesefficiently,theratedroppedby80percentintheM5addedsamples.Likewise,whenaddedtoredbloodcells,infectionbythemalariaparasitedroppedby80percent.Actually,thecodonshufflingapproachismoregeneralandextendabletofightotherpathogenstoo.AndthisapproachisquiteakintoLego,thetoygamewithinterlockingplasticbricks,whichcanbeputtogethertomakemodelsofobjectslikebuildings.WhileLegoisagameofpleasure,thismolecularLegoopensthedoorfordrugdiscovery.
Ebolavaccinesafe,generatesimmuneresponse,showstrial
ThefirsttrialresultsofEbolavaccineatOxfordUniversitysuggestthevaccinehasanacceptablesafetyprofileandisabletogenerateanimmuneresponse.TheEbolavaccinewaswelltolerated.Itssafetyprofileisprettymuchaswehadhoped,saidprofessorAdrianHilloftheJennerInstituteatOxfordUniversitywholedthetrial.TheresultssuggestthatthevaccineissuitableforfurthertestinginWestAfricaduringthecurrentoutbreak.TheEbolavaccineisbeingcodevelopedbytheUSNationalInstitutesofHealth(NIH)andpharmaceuticalfirmGlaxoSmithKline(GSK)againsttheZairestrainofEbola,whichistheonecirculatinginWestAfrica.ThefirstdosesforuseinlargescaletrialsinWestAfricahavebeendeliveredtoLiberiabyGSK.ThevaccineusesasingleEbolavirusgeneinachimpanzeeadenovirustogenerateanimmuneresponse.AsitdoesnotcontaininfectiousEbolavirusmaterial,itcannotcauseapersonwhoisvaccinatedtobecomeinfectedwithEbola.Duringthetrial,60healthyvolunteerswerevaccinatedattheJennerInstitute.Theresultsshowedsafetydataandimmuneresponsesforthevolunteersfor28daysafterimmunisation.Twopeopleexperiencedamoderatefeverwithin24hoursofreceivingthevaccinebutthispassedwithinaday.Peopletypicallyexperiencedmildsymptomsthatlastedforoneormaybetwodays,suchaspainorreddeningattheinjectionsite,andoccasionallypeoplefeltfeverish,professorHillexplained.Theprimarygoalofthetrialwastoassesssafety.However,thescientistsalsoassessedimmuneresponsestoEbolaseeninthevolunteersbeforeandaftervaccination.Importantly,thevaccinegeneratedimmuneresponsesagainstEbolainthevolunteers.Levelsofantibodiesincreasedoveraperiodof28daysaftervaccinationandtherewasnosignificantdifferenceinthelevelsseenatdifferentdoses.LevelsofTcellscellularimmunityistheotherarmofthebodysimmunesystempeakedat14days.LargertrialsinWestAfricaareneededtotellwhetherimmuneresponsesarelargeenoughtoprotectagainstEbolainfectionanddisease,theteamadded.TheOxfordUniversitytrialisoneofseveralsafetytrialsoftheGSK/NIHvaccinecandidateintheUSA,
Britain,MaliandSwitzerlandthathavebeenfasttrackedinresponsetotheEbolaoutbreakinWestAfrica.TheOxfordUniversityscientistshavealsobeguntestingthesafetyofacandidateboostervaccineagainstEbola,tofindoutwhetheritcouldfurtherincreasetheimmuneresponses.AccordingtotheWorldHealthOrganisation(WHO),theEbolaoutbreakinWestAfricahaskilledover8,000peoplesofar.TheinitialfindingswerepublishedintheNewEnglandJournalofMedicine(NEJM).
AffordableswinefluvaccinethatnevermadeitThedeathofover30personsintwomonthsandaspateofswineflucaseshaveforcedthepublicinHyderabadtogoforvaccineshotsbyspendinganywherebetweenRs.450andRs.1,000pershot.Thosewhocanaffordareabletoaccessthevaccine,butthevastmajoritywhocantareanxiousaboutthesafetyoftheirnearanddearones.Ironically,doyouknowthattheswinefluvaccinecouldhavebeenmadeavailableforjustRs.100inHyderabad?Couldthelivesofover30peoplelostbeensavedifgovernments,bothCentreandState,promotedindigenousfluvaccine?CMD,BharatBiotech,Dr.KrishnaEllasaysthedeathscouldhavebeenprevented.AuthoritieseffectivelykilledtheIndianswinefluvaccineafterpromotingitinitially.Theybackedoutleavingmillionsofunsoldswinefluvaccinesin201011.WecouldhaveofferedabetterversionofH1N1vaccineforjustRs.100andlivescouldhavebeensaved,herues.Atpresent,H1N1vaccinesbeinggiveninHyderabadareimported.Ironically,thecellculturevaccineofBharatBiotechwasmanufacturedatGenomeValleyinHyderabadin201011.TheGOIhadgiventhreeIndianpharmacompaniesnearlyRs.10croretomanufactureaffordablevaccinewhenswinefluwasatitspeakandpeopleweredying.Later,theypulledtheplugandweevenreturnedthemoney,hesaid.AlongwithBharatBiotech,SerumInstitute,PuneandPanaceaBiotech,NewDelhiweretoproduceindigenousswinefluvaccine.However,afterthepeakof2009and2010,thecasesofswineflucasesstartedtodipandtheneedforavaccinewasnotfelt,doctorsprivytotheissuesaid.In201011,millionsofdosesofindigenousH1N1vaccinesweredestroyedbecausetherewerenotakers.Theywereproducedinthehopethatgovernmentagencieswouldstockthemforhealthcareworkersandpublicwouldgetvaccinatedforprevention.Lookwhatshappeningnow.Swineflucasesaregoingup,thereislossoflifeandwinterwillbelonginNorthIndia.Wecouldhavesavedlives.Decisionmakersshouldhavevision,headded.
IndiancompaniescouldhavemadeshotsavailableforRs.100hadthegovernmentencouragedthem
ExpertsgivetipstokeepswinefluatbayWhiletherewasnoneedforpeopletogetpanickyaboutswineflu,therewaseveryneedforthemtobecautious,expertssaid.ChairmanofacorporatehospitalY.RameshBabusaidthatthosesufferingfromcoughandcoldshouldnotcoughorsneezeintheopen.TissuepaperTheyshouldhaveahandkerchief,tissuepaperwasevenbetterbecauseitcouldbedisposedofsafely.Hesaidthatonly0.1percentofthepersonsinfectedbyswineflufacedsituationsthatwerelifethreatening.PulmonologistwithacorporatehospitalM.S.Gopalakrishnasaidthatpersonsinfectedbyswinefluwere
contagiousforsevendaysandH1N1viruswasactivefortwohoursinthedropletsthataresneezedorcoughedoutbyapatient.ThreecategoriesHesaidthoseinfectedbyswineflucouldbeclassifiedintothreecategories.Acategorypatientswithmildfever,cough,sourthroat,bodyandheadache,diarrhoeaandvomitingshouldbetreatedsymptomatically.HomeisolationBcategorypatientswithhighgradefeverandseveresourthroatsalongwithalltheothersymptomsofAcategorypatientsrequiredhomeisolationandtreatmentwithOseltamivir(Tamiflu).Ccategorypatientswithalltheabovesymptomscombinedwithbreathlessness,chestpain,bluishdiscolourationofnails,etc.shouldbehospitalised.SpecialistinInternalMedicineC.PadmawhoworkedintheUSAwhenswineflubecameapandemic(2009)saidonlypatientswhorequiredhospitalisationneedtobetestedforswineflu.AcorporatehospitalmanagingdirectorandspecialistincriticalcarePadmaMovvasaidallsuspectedcasesofswinefluwerebeingtreatedwithOseltamivir,becausefacilitiesfordetectingthespecificfluwasnotavailableinVijayawada.EarlytreatmentbetterTheearliertreatmentwasstartedwiththespecificantiviral,bettertheresults,shesaid.
AncientstarwithfiveEarthsizeplanetsdiscovered
AfteranalysingoverfouryearsofdatafromNASAsKeplerspacecraft,ateamofastronomershasdiscoveredastarthatis11.2billionyearsoldandhasatleastfiveEarthsizeplanets.ThefindingsshowthatEarthsizeplanetshaveformedthroughoutmostoftheuniverses13.8billionyearhistory,leavingopenthepossibilityfortheexistenceofancientlifeinthegalaxy,saidTiagoCampante,researchfellowattheUniversityofBirminghamwholedtheresearchproject.ThepaperdescribesKepler444,astarthatis25percentsmallerthanourSunandis117lightyearsfromEarth.ThestarsfiveknownplanetshavesizesthatfallbetweenMercuryandVenus.Thoseplanetsaresoclosetotheirstarthattheycompletetheirorbitsinfewerthan10days.Atthatdistance,theyareallmuchhotterthanMercuryandarenothabitable.Kepler444isverybrightandcanbeeasilyseenwithbinoculars.Thisisoneoftheoldestsystemsinthegalaxy,addedSteveKawaler,anIowaStateUniversityprofessorofphysicsandastronomywhoisalsothecoauthorofthepaper.Kepler444camefromthefirstgenerationofstars.Thissystemtellsusthatplanetswereformingaroundstarsnearlysevenbillionyearsbeforeourownsolarsystem,Kawalernoted.Planetarysystemsaroundstarshavebeenacommonfeatureofourgalaxyforalong,longtime.ThatdiscoveryisgoingtohelpastronomerslearnevenmoreaboutthehistoryoftheMilkyWay.FromthefirstrockyexoplanetstothediscoveryofanEarthsizeplanetorbitinganotherstarinitshabitablezone,wearenowgettingfirstglimpsesofthevarietyofGalacticenvironmentsconducivetotheformationofthesesmallworlds,theastronomerswrote.Asaresult,thepathtowardamorecompleteunderstandingofearlyplanetformationintheGalaxystartsunfoldingbeforeus,theyconcludedinthepaperthatappearedintheAstrophysicalJournal.
OfDarwinsline,theprofessorhasaposerondevelopment
Aresocialmovementsantidevelopment?Ordotheyexemplifytherealessenceoftheterm?
Isequitabledistributionofnaturalresourcestherealmeaningofdevelopment?Orwasittheexhaustionofsuchresourcesthroughrapidindustrialisation?ThesewerethequestionsposedbyprominentanthropologistFelixPadel,whoisadescendentofevolutionarybiologistCharlesDarwin.Dr.Padel,whowasdeliveringalectureonWhatisRealDevelopmentBalancingEcologyandEconomyatOsmaniaUniversitysDepartmentofPoliticalSciencesaidthatmanysocialmovementsinIndiaandothercountrieswereresistingthetakeoveroflandandresources,orchestratedthroughforeigninvestment.Suchmovementsweregenerallyledbymarginalisedgroupsandwomen.Hesoughttoknowifthesemovementswereantidevelopmentordidtheyrepresenttherealessenceoftheterm.Realdevelopment,hefelt,wasthepropersharingofresourcestoguaranteeproperaccesstoeveryoneforfood,water,justiceandhealthcare.Prof.G.KrishnaReddy,coordinatorathedepartmentsCentreforAdvancedStudiessaidDr.Felix,whohaspublishedextensivelyontribalissues,willbedeliveringaseriesoflectures.
Newprimitivehumanspeciesdiscovered?ResearchershaveidentifiedthefirstknownprehistorichumanfromTaiwanwhichmayrepresentanentirelynewspeciesthatlivedasrecentlyas10,000yearsago.Thenewlydiscoveredbigtoothedhuman,Penghu1,mighthavecoexistedandeveninterbredwithourspecies.ThediscoverysupportsthegrowingbodyofevidencethatHomosapienswasnottheonlyspeciesfromourgenuslivinginEuropeandAsiabetween200,000and10,000yearsago.TheavailableevidenceatleastdoesnotexcludethepossibilitythattheysurviveduntiltheappearanceofHomosapiensintheregion,anditistemptingtospeculateabouttheirpossiblecontact,coauthorYousukeKaifutoldDiscoveryNews.Dr.KaifuisanassociateprofessorintheDepartmentofBiologicalSciencesatTheUniversityofTokyo.Dr.Kaifu,leadauthorChunHsiangChang,andtheirteamstudiedtheremainsofthenewhumanajawbonewithbigteethstillinit,dredgedupoffthecoastofTaiwaninPenghuchannel.ChangandhisteamsaidPenghu1couldrepresentanewhumanspeciesoraregionalgroupofHomoerectus,alsoknownasUprightMan.Heandhiscolleaguesbelievethat,duetoitssize,thejawbonecamefromanadultindividualandpossiblyasenior,becauseitsteetharewornseverely.Jawbonessize
ThejawbonessizefurtherrevealsthatPenghu1wasnotadwarf,unliketinyHomofloresiensis,whichlivedontheislandofFlores,Indonesia,whereotheranimalswerealsosmallerthanusual.
Penghu1,instead,livedonwhatwasthenmainlandAsiainanecosystemthatincludedmanyotheranimals.WhilePenghu1spreciseidentityremainsamysteryfornow,researchersaresurethatthisbigtoothedhumanwasnotamemberofourspecies.
Fossilfindspushbacksnakeorigins
TheoldestfoundinOxfordisofa25cmreptilethatlived167millionyearsago
SnakeshavebeenslitheringonEarthfarlongerthananyoneeverrealised.ScientistsonTuesdaydescribedthefouroldestknownsnakefossils,themostancientofwhichwasaroughly25cmreptilecalledEophisunderwoodiunearthedinaquarrynearOxford,England,thatlivedabout167millionyearsago.
TheremarkablefossilsfromBritain,PortugalandtheUnitedStatesrewritethehistoryofsnakeevolution,pushingbacksnakeoriginsbytensofmillionsofyears.Untilnow,theoldestsnakefossildatedfromabout102millionyearsago,saidUniversityofAlbertapaleontologistMichaelCaldwell,wholedthestudypublishedinthejournalNatureCommunications.Scientistssaysnakesevolvedfromlizards,andanumberofpreviouslydiscoveredfossilsofprimitivesnakesfeaturedsmallbacklegs.ThosedescribedonTuesdaydidnotincludeentireskeletons,buttheresearcherssayallfourmayhavehadsomeformofreducedforelimbsandhindlimbs.Thatdoesnotmeantheywalked.Itseemsprobablethattheywereslithering,sotospeak,thoughthelimbsmightstillhavebeenusedforgrasping,Mr.Caldwellsaid.Snakeshavegeneratedfearandfascinationsinceancienttimes,saidpaleontologistSebastinApesteguaofArgentinasNationalScientificandTechnicalResearchCouncil(CONICET)andUniversidadMaimonides,anotheroftheresearchers.However,weknowverylittleabouttheirveryorigins,saidMr.Apestegua.Thefoursnakeslivedduringtheageofdinosaurs.Eophis,theoldest,wasaswampdwellerthatprobablyatesmallminnows,insectsandtadpoles.Thelargest,namedPortugalophislignitesanddiscoveredinacoalmineincentralPortugal,measuredabout1.2metresandwas155millionyearsold.Itmayhaveeatensmallmammals,youngdinosaurs,lizards,birdsandfrogs.Diablophisgilmorei,asnakefromabout155millionyearsago,wasfoundinwesternColorado.ItwasabitlargerthanEophisandprobablyatesimilarprey.Parviraptorestesi,foundinseacliffsnearSwanage,England,wasabout60cmlongand144millionyearsold.Caldwellsaidthefoursnakesskullanatomywassimilartomodernsnakesandotherfossilsnakes.Caldwellsaidthecharacteristicsnakeskulldesignlikelyemergedbeforethesereptilesacquiredtheirelongatedandleglessbodyplan.
ThebestshotyetoficydwarfplanetCeresIfyouhaventheardofCeres,aplanetthatsitssomewherebetweenMarsandJupiter,youcanbeforgiven.Itwasoriginallyclassifiedasatrueplanetinthe1800s,thendemotedtoanasteroidandfinallyin2006promotedagainasadwarfplanetastatusitnowshareswithPluto.ButtheicyCeres,rightthroughthechangingnomenclature,hasheldauniquefascinationforscientists:notleastbecauseitisthoughttocontainvastreservesofwater.Andso,whenthesharpestimageyetofthedwarfplanetemerges,itiscausetocelebrate.NASAsDawnspacecrafthassentbackapictureofCerestakenfromadistanceof237,000km.Theimagealthoughfairlyblurryis30percenthigherinresolutionthanthosetakenbyNASAsHubbleSpaceTelescope10yearsagofrom241millionkilometresaway.AsthespacecraftmovesclosertoCeres,theimagessentbackwillgetbetter.DawnwillenterintoCeresorbitonMarch6tocapturedetailedimagesandmeasurevariationsinreflectedlighttogetinsightsintotheplanet'ssurfacecomposition.Lastyear,astronomerswhostudieddatafromESAsHerschelSpaceObservatoryreportedplumesofvapouremergingfromCeressurface,suggestingthatitcontainedregionsrichinwaterice.Dawnwillbethefirstspacecrafttovisitanydwarfplanet.At950kmdiameterCeresisthesmallestknowndwarfplanet,butthelargestobjectintheasteroidbeltbetweenMarsandJupiter.