Amplified fragment length polymorphisms reveal genetic differentiation among strains of Xanthomonas albilineans.

Xanthomonas albilineans, the causative agent of leaf scald disease (LSD), colonizes the vascular system of sugarcane (Saccharum spp. hybrids). In this study X.

Aerobic biodegradation of dichloroethenes by indigenous bacteria isolated from contaminated sites in Africa.

The widespread use of tetrachloroethene (PCE) and trichloroethene (TCE) as dry cleaning solvents and degreasing agents for military and industrial applications has resulted in significant environmental contamination worldwide. Anaerobic biotransformation of PCE and TCE through reductive dechlorination frequently lead to the accumulation of dichloroethenes (DCEs), thus limiting the use of reductive dechlorination for the biotransformation of the compounds. In this study, seven bacteria indigenous to contaminated sites in Africa were characterized for DCE degradation under aerobic conditions.

Microbial community profiling in cis- and trans-dichloroethene enrichment systems using denaturing gradient gel electrophoresis.

The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations with a low abundance. Accordingly, this study was undertaken to investigate the diversity of the microbial community during the biodegradation of cis- and trans-dichloroethenes in soil and wastewater enrichment cultures. Community profiling using PCR targeting the 16S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE) revealed an alteration in the bacterial community profiles with time.

Analysis of the mechanisms of fluoroquinolone resistance in urinary tract pathogens.

Objectives: To characterize the mechanisms of fluoroquinolone resistance in urinary tract pathogens exhibiting a multiple antibiotic resistance phenotype as well as a high-level resistance to fluoroquinolones.

Methods: Nineteen Escherichia coli urinary tract infection pathogens exhibiting high-level resistance to fluoroquinolones were characterized in this study. Alterations in outer membrane proteins (OMPs) and lipopolysaccharide (LPS) were analysed by PAGE.

Biostimulation and bioaugmentation enhances aerobic biodegradation of dichloroethenes.

The accumulation of dichloroethenes (DCEs) as dominant products of microbial reductive dechlorination activity in soil and water represent a significant obstacle to the application of bioremediation as a remedial option for chloroethenes in many contaminated systems. In this study, the effects of biostimulation and/or bioaugmentation on the biodegradation of cis- and trans-DCE in soil and water samples collected from contaminated sites in South Africa were evaluated in order to determine the possible bioremediation option for these compounds in the contaminated sites. Results from this study indicate that cis- and trans-DCE were readily degraded to varying degrees by natural microbial populations in all the soil and water samples tested, with up to 44% of cis-DCE and 41% of trans-DCE degraded in the untreated soil and water samples in two weeks.

Molecular profiling demonstrates limited diversity amongst geographically separate strains of Ustilago scitaminea.

Intraspecies diversity within Ustilago scitaminea isolates from South Africa, Reunion Island, Hawaii and Guadeloupe was assessed by RAPDs, bE mating-type gene detection, rDNA sequence analysis, microscopy and germination and morphological studies. Except for sequence data, the other analyses yielded no differences in the isolates that could be used in a phylogenetic separation. Mycelial DNA of the SA isolate shared 100% sequence identity with that of mycelial DNA cultured from in vitro produced teliospores of the parent cultivar.

Aerobic dechlorination of cis- and trans-dichloroethenes by some indigenous bacteria isolated from contaminated sites in Africa.

The innate toxicity of dichloroethenes (DCEs) and their tendency to be reduced to vinyl chloride (VC) (a known human carcinogen) is a cause for environmental concern. Aerobic bacteria capable of growth on cis- and trans-DCEs as sole carbon and energy sources were isolated by enrichment culture technique and identified to belong to the genera; Bacillus, Pseudomonas and Acinetobacter. Axenic and mixed cultures of the bacterial isolates utilized DCEs at concentrations above the maximum contaminant level allowable in drinking water by the Environmental Protection Agency.