title: Community dynamics and heterogeneities in mixed bacterial communities subjected to nutrient periodicities.
abstract: Sixteen replicate microcosms were inoculated with a mixed assemblage of heterotrophic bacteria and provided with discrete pulses of protein as carbon and energy source. The dynamics of community structure were monitored by 16S rRNA gene polymerase chain reaction denaturant gradient gel electrophoresis (PCR-DGGE). The results were consistent with a strong role for biological interactions in maintaining diversity. Replicate microcosms developed different microbial communities. For systems exposed to nutrient pulses every 7 days, the number of DGGE bands averaged 13 +/- 4 (mean +/- SD) and the Dice similarity coefficient between pairs ranged from 0.08 to 0.67. In each of 16 systems provided protein once each day, there were dynamic changes over the first 30 days but community composition was stable over the next 20 days. However, most systems differed from each other; two-thirds of the pairwise comparisons had similarity coefficients in the range of 0.35-0.63. These 16 systems contained 10 +/- 2 phylotypes (mean +/- SD) and in aggregate 34 phylotypes were found in the 16 systems. Most phylotypes were found in < 25% of the systems, and there were not strong networks of association among phylotypes.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA. akonopka@purdue.edu
authors.forename: Allan
authors.initials: A
authors.lastname: Konopka
authors.forename: Militza
authors.initials: M
authors.lastname: Carrero-Colon
authors.forename: Cindy H
authors.initials: CH
authors.lastname: Nakatsu
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D003470:Culture Media / Q000737:chemistry; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D007700:Kinetics; D010507:Periodicity; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D003470:Culture Media; D012336:RNA, Ribosomal, 16S