Bacterial Community Composition and Activity in Urban Rivers in Thailand and Malaysia.

Abstract

The phylogenetic composition and physiological activity of bacterioplankton communities in two different rivers in Southeast Asian countries, the Kelang River basin in Malaysia and Chao Phraya River in Thailand, which are polluted by untreated or incompletely treated sewage, were analyzed by fluorescent in situ hybridization (FISH) and FISH combined with the direct viable count technique (DVC-FISH). The results were also compared with those from temperate zone habitats in eutrophic rivers in Osaka, Japan. FISH detected 56% to 78% of total cells with the probe EUB338 targeted for the domain Bacteria in samples from the Kelang River basin, compared with 14% to 33% in samples from the Chao Phraya River. DVC-FISH with an antibiotic cocktail increased the fraction of bacteria detectable with EUB338 in the Chao Phraya River (72% to 75% of total bacteria), while no appreciable change was found in samples from the Kelang River basin. These results show that in situ physiologic activity of resident bacteria was generally high in the Kelang River basin and low but present in the Chao Phraya River. Bacterial community structures in both rivers were dominated by the beta (5% to 39%) and gamma (4% to 41%) subclasses of Proteobacteria. In river water samples from Osaka, bacterial community structures determined by FISH were dominated by the beta subclass, but those determined by DVC-FISH were dominated by both beta (26% to 39%) and gamma (17% to 47%) subclasses. This result implies that in situ physiological activity of the gamma subclass is low in the eutrophic river in Osaka, but those bacteria have the potential for cell division.

16S Ribosomal RNA Gene-Based Phylogenetic Analysis of Abundant Bacteria in River, Canal and Potable Water in Bangkok, Thailand

“…The two bacteria common to all freshwater samples belonged to Gammaproteobacteria; 1Al0202 had 99% similarity with a partial sequence isolated from lake Biwa, Japan's largest freshwater lake, and 2Al0202 belonged to Acinetobacter sp. Kenzaka used fluorescence in situ hybridization to analyze bacterial communities in freshwater samples from Chao Phraya River and reported that 30-40% of bacteria belonged to Gammaproteobacteria, 13) similar to our results. The dominant bacterium in Bangkok Noi Canal (8BN0202) belonged to Gram-positive bacteria and was closely related to Staphylococcus sciuri.…”

“…The canal is 10-20 m wide, while the river spans more than 100 m. The water quality of the Chao Phraya River has been monitored by the Pollution Control Department of Thailand, and biochemical oxygen demand (BOD) was 1.1-8 mg/l (average 3.5 mg/l) in metro-politan Bangkok. 13) One tap water sample stored in a plastic bucket at a riverside house and one from a water reservoir at a house in the city were also collected as oligotrophic aquatic environmental samples.…”

Characterization of the microbial community in a lotic environment to assess the effect of pollution on nitrifying and potentially pathogenic bacteria

“…The study presented here attempted to identify the specific differences in the microbial community at two sites along the São Pedro stream that is influenced by urbanisation. The abundance of bacteria (1×10 7 ) obtained in the urban area of study was in agreement with Kenzaka et al (2001) and within the range reported for other polluted rivers that were considered eutrophic systems by Yamaguchi et al (1997). The concentration of dissolved nutrients obtained in this study in the urban area also corroborated with classifying this area as an eutrophic system since this classification is within the range of nutrients found at this site.…”

“…Rivers and streams are important reserves of water available for human consumption, animal life, agriculture, and industry (Kenzaka et al, 2001). Therefore, there is need to conserve this resource.…”

“…In this regard, many studies have demonstrated that knowledge of the structure and dynamics of the microbial community in rivers and streams is essential, mainly due to their role in several biogeochemical cycles (Brümmer et al, 2000;Araya et al, 2003;Kostanjšek et al, 2005). This is especially important for environments modified by anthropogenic action (Böckelmanna et al, 2000;Kenzaka et al, 2001;Tiquia, 2010).…”