Miks on mikroorganismide mitmekesisusest nii vhe teada? See tuleneb metoodilistest probleemidest: ei ole olemas laboratoorset kasvukeskkonda, mis sobiks heaegselt paljudele bakteritele vi arhedele; raske on eraldada pindadele kinnitunud vi biokilest mikroorganisme; suur osa teadaolevast informatsioonist bakterite kohta phineb puhaskultuurides saadud tulemustel, mis ei pruugi kehtida looduslikus keskkonnas. Suur osa (95-99%) vees ja mullas elavatest bakteritest on mittekultiveeritavad (nonculturable) bakterid. Need on bakterid, kes on eeldatavasti funktsionaalsed, vga aeglase metabolismiga ja kohanenud oligotroofsetele (vga madal toitainete kontsentratsioon) tingimustele, mida ei ole siiani vimalik laboris jljendada. Selleks, et uurida ja kirjeldada mikroorganismide (bakterite, arhede ja seente) mitmekesisust keskkonnas, on kasutusele vetud molekulaarsed meetodid, mille puhul ei ole vaja organismi eelnevalt isoleerida puhaskultuuri.
of this organism is by suitable liquid and of humans and animals. It is glucose- and solid growth media designed for the organ- lactose-positive and indole and methyl red ism and rapid tests involving ELISA, PCR, positive but Voges-Proskauer and citrate Ribotyping, etc. One complication in study- negative. The most useful way to classify the ing this organism is the presence of viable but species is by serotyping, using antibodies nonculturable populations of C. jejuni in the against O, H, and K antigens of various environment. strains of E. coli. Proper food-processing techniques (heat- Most E. coli isolated from the environ- ing, cooling, chemical treatment of foods, ment are not pathogenic. However, there are etc.) will control this fragile organism. Its six classes of pathogenic and diarrheagenic prevalence as a food-borne pathogen can E. coli
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