As described recently (Janse et al. 1999; Limnol Oceanogr 44(6):1447–1457), mucopolysaccharides of the marine microalga Phaeocystis can be degraded in enrichment cultures. In this paper we report on the characterization of the microbial community in such enrichments. Denaturing gradient gel electrophoresis (DGGE) profiles that were obtained during mucopolysaccharide degradation showed a substan...

Assessing and predicting bloom dynamics and toxin production by Microcystis requires analysis of toxic and nontoxic Microcystis genotypes in natural communities. We show that genetic differentiation of Microcystis colonies based on rRNA internal transcribed spacer (ITS) sequences provides an adequate basis for recognition of microcystin producers. Consequently, ecological studies of toxic and n...

Chloramination is often the disinfection regimen of choice for extended drinking water systems. However, this process is prone to instability due to the growth of nitrifying bacteria. This is the first study to use alternative approaches for rapid investigation of chloraminated drinking water system instability in which flow cytometric cell sorting of bacteria with intact membranes (membrane-in...

Salmonella isolates were collected from 2 commercial turkey processing plants (A and B) located in different US geographical locations. Isolates recovered at different stages of processing were subjected to 2 genotype techniques [PAGE and denatured gradient gel electrophoresis (DGGE)] to determine their usefulness for Salmonella serotyping. Primers used for PCR amplification were to a highly co...

We monitored bacterioplankton communities from Chesapeake Bay over 2 years (2002–2004) by use of denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene. Chesapeake Bay bacterioplankton exhibited a repeatable annual pattern and strong seasonal shifts. In winter, the bacterial communities were dominated by Alphaproteobacteria and Actinobacteria, whereas in summer, the predo...

Healthy children, aged between 5 and 9 years who had not taken antibiotics in the preceding three months were recruited. Plaque was sampled from the gingival crevice of either the lower left or lower right first permanent molar to estimate the prevalence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Tannerella forsythensis which have been implicated as main etiological a...

OBJECTIVE This study aimed to investigate the possible topical effect of a broad-spectrum antibiotic on dental biofilm formed in situ in the absence or presence of sucrose. METHODS A crossover study was conducted in three phases of 14 days each, during which 11 volunteers wore palatal devices containing 6 enamel blocks covered with meshes to allow biofilm formation. Dental blocks were extraor...

Cyanophages (viruses that infect cyanobacteria) are abundant in the marine environment and are thought to be a significant factor in determining the population dynamics of members of the unicellular phycoerythrin-containing cyanobacteria of the genus Synechococcus. In an effort to use molecular techniques to characterise cyanophage populations, a conserved region from the cyanophage genome was ...

The microbial spoilage of beef was monitored during storage at 5 degrees C under three different conditions of modified-atmosphere packaging (MAP): (i) air (MAP1), (ii) 60% O2 and 40% CO2 (MAP2), and (iii) 20% O2 and 40% CO2 (MAP3). Pseudomonas, Enterobacteriaceae, Brochothrix thermosphacta, and lactic acid bacteria were monitored by viable counts and PCR-denaturing gradient gel electrophoresis...