We used standard periphyton samplers to examine the colonization pattern of periphytic algae on artificial substrates (glass slides) in Lam Tsuen River, Hong Kong, in dry (winter) and wet (summer) seasons. In each sea...We used standard periphyton samplers to examine the colonization pattern of periphytic algae on artificial substrates (glass slides) in Lam Tsuen River, Hong Kong, in dry (winter) and wet (summer) seasons. In each season, six replicated slides were retrieved randomly and replaced by new slides at weekly intervals over a period of 6 weeks. We thus obtained two batches of slides, both with a series of different exposure times (1 to 6 weeks): one batch was set up at the same time (start of the sampling) and the other was harvested at the same time (end of the sampling). Changes in taxonomic composition, species diversity (Shannon-Wiener diversity index), standing crop (in terms of cell density and cell biovolume), and abundance of the abundant algal species were monitored and compared between the two batches of slides. The succession patterns of the periphytic algae were similar between the two batches in each season, while more remarkable differences were observed between the two seasons, suggesting that either batch would be suitable for a colonization study of periphytic algae. The cell density was dominated by diatoms in both seasons, while the cell biovolume was dominated by diatoms in winter and by green algae in summer. The cell density and biovolume attributed to blue green algae was relatively small. Most of the diatom species exhibited similar colonization patterns throughout the experiment, while green algae showed different succession patterns in different seasons or sampling methods, indicating that diatoms are better bio-indicators than green algae for a periphyton colonization study. In general, the diversity indices and the standing crops reached their maximums at around week 4, and they were higher in summer than in winter.展开更多
Ubiquitin, a highly conserved stress-related protein, is assigned multiple functions, such as DNA processing, protein degradation, and ribosome synthesis. The Crassostrea hongkongensis ubiquitin gene (designated ChUbL...Ubiquitin, a highly conserved stress-related protein, is assigned multiple functions, such as DNA processing, protein degradation, and ribosome synthesis. The Crassostrea hongkongensis ubiquitin gene (designated ChUbL40) was cloned by a combination of suppressive subtractive hybridization (SSH) and rapid amplification of cDNA ends (RACE). The full-length cDNA of ChUbL40 is 496 bp in length, consisting of a 5' untranslated region (UTR) of 34 bp, a 3'-UTR of 75 bp and an open reading frame of 387 bp encoding a ubiquitin fusion protein of 128 amino acids. Analysis of the amino acid sequence of ChUbL40 reveals that UbL40 is highly conservative during evolution. The expression patterns of ChUbL40 gene in various tissues were examined by real-time PCR. The expression level of ChUbL40 in haemocytes is down-regulated at 4 h and gradually returned to its original level from 6 h to 24 h after Vibrio alginolyticus challenge. Our results suggest that ChUbL40 is ubiquitously expressed and plays an important role in immune defense against bacterial challenge.展开更多
A membrane bioreactor （MBR） was established for treating harbor oily wastewater. It showed good removal performance for chemical oxygen demand （COD）, oil content, suspended solids （SS）, and other pollutants. How...A membrane bioreactor （MBR） was established for treating harbor oily wastewater. It showed good removal performance for chemical oxygen demand （COD）, oil content, suspended solids （SS）, and other pollutants. However, serious membrane fouling occurred. It was recognized that the extracellular polymeric substances （EPS） accumulated on the membrane surface, especially the proteins, were of great importance for the transmembrane pressure （TMP） increment and membrane fouling. The MBR was optimized via improving aeration rate and reducing the ratio of Ar/Ad （At and Ad are the cross-sectional areas of the riser and the downcomer of the MBR）. The increasing rate of TMP was slowed, indicating that the optimization strategy could effectively mitigate membrane fouling. Microbial community evolution was monitored and analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE）, cloning, and sequencing of 16S ribosomal ribonucleic acid （rRNA） fragments. Results revealed that low community shift occurred during the whole operational period. Geobacter sp. and Rhodocyclales sp., which have also been identified by other studies in a petroleum refinery wastewater MBR or an infiltration basin receiving highway runoff, dominated in the MBR system throughout. Comamonas sp. was thought to accommodate the lower aeration rate in this study, while Rhodocyclales sp. preferred the higher aeration rate. In addition, during the operational time under high organic loading rate, a few species were present in abundance, and may have been responsible for the good removal performance at this time.展开更多
基金Supported by the National Natural Science Foundation of China (Nos.30770393 30770340)+1 种基金the National Major Program of Science and Technology for Water Pollution Control and Restoration in China (Nos.2009ZX07423-003,2009ZX07101-011)the Natural Science Foundation of Guangdong Province,China (No.06301361)
文摘We used standard periphyton samplers to examine the colonization pattern of periphytic algae on artificial substrates (glass slides) in Lam Tsuen River, Hong Kong, in dry (winter) and wet (summer) seasons. In each season, six replicated slides were retrieved randomly and replaced by new slides at weekly intervals over a period of 6 weeks. We thus obtained two batches of slides, both with a series of different exposure times (1 to 6 weeks): one batch was set up at the same time (start of the sampling) and the other was harvested at the same time (end of the sampling). Changes in taxonomic composition, species diversity (Shannon-Wiener diversity index), standing crop (in terms of cell density and cell biovolume), and abundance of the abundant algal species were monitored and compared between the two batches of slides. The succession patterns of the periphytic algae were similar between the two batches in each season, while more remarkable differences were observed between the two seasons, suggesting that either batch would be suitable for a colonization study of periphytic algae. The cell density was dominated by diatoms in both seasons, while the cell biovolume was dominated by diatoms in winter and by green algae in summer. The cell density and biovolume attributed to blue green algae was relatively small. Most of the diatom species exhibited similar colonization patterns throughout the experiment, while green algae showed different succession patterns in different seasons or sampling methods, indicating that diatoms are better bio-indicators than green algae for a periphyton colonization study. In general, the diversity indices and the standing crops reached their maximums at around week 4, and they were higher in summer than in winter.
基金Supported by the National Basic Research Program of China (973 Program) (No.2010CB126404)the CAS/SAFEA International Partnership Program for Creative Research Teams (No.KZCX2-YW-T001)the Research Program for Young Scientists at SCSIO
文摘Ubiquitin, a highly conserved stress-related protein, is assigned multiple functions, such as DNA processing, protein degradation, and ribosome synthesis. The Crassostrea hongkongensis ubiquitin gene (designated ChUbL40) was cloned by a combination of suppressive subtractive hybridization (SSH) and rapid amplification of cDNA ends (RACE). The full-length cDNA of ChUbL40 is 496 bp in length, consisting of a 5' untranslated region (UTR) of 34 bp, a 3'-UTR of 75 bp and an open reading frame of 387 bp encoding a ubiquitin fusion protein of 128 amino acids. Analysis of the amino acid sequence of ChUbL40 reveals that UbL40 is highly conservative during evolution. The expression patterns of ChUbL40 gene in various tissues were examined by real-time PCR. The expression level of ChUbL40 in haemocytes is down-regulated at 4 h and gradually returned to its original level from 6 h to 24 h after Vibrio alginolyticus challenge. Our results suggest that ChUbL40 is ubiquitously expressed and plays an important role in immune defense against bacterial challenge.
基金supported by the Science and Technology Project of the Ministry of Transport(No.2011-329-224-330)the National Nonprofit Institute Research Grants of Tianjin Research Institute for Water Transport Engineering(Nos.TKS100216,TKS130206,and TKS160215),China
文摘A membrane bioreactor （MBR） was established for treating harbor oily wastewater. It showed good removal performance for chemical oxygen demand （COD）, oil content, suspended solids （SS）, and other pollutants. However, serious membrane fouling occurred. It was recognized that the extracellular polymeric substances （EPS） accumulated on the membrane surface, especially the proteins, were of great importance for the transmembrane pressure （TMP） increment and membrane fouling. The MBR was optimized via improving aeration rate and reducing the ratio of Ar/Ad （At and Ad are the cross-sectional areas of the riser and the downcomer of the MBR）. The increasing rate of TMP was slowed, indicating that the optimization strategy could effectively mitigate membrane fouling. Microbial community evolution was monitored and analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE）, cloning, and sequencing of 16S ribosomal ribonucleic acid （rRNA） fragments. Results revealed that low community shift occurred during the whole operational period. Geobacter sp. and Rhodocyclales sp., which have also been identified by other studies in a petroleum refinery wastewater MBR or an infiltration basin receiving highway runoff, dominated in the MBR system throughout. Comamonas sp. was thought to accommodate the lower aeration rate in this study, while Rhodocyclales sp. preferred the higher aeration rate. In addition, during the operational time under high organic loading rate, a few species were present in abundance, and may have been responsible for the good removal performance at this time.
