Current trophic status and trend of Chinese freshwater lakes were investigated in this study. The results showed that all lakes studied were commonly undergoing the eutrophication process, water quality decreased and lake’s ecosystem is being declined. Most of the urban lakes are facing serious eutrophication. Many medium-sized lakes are in metrophic or eutrophic status, some local water are even approaching the hypertrophic level. The famous five freshwater lakes in China have entered into eutrophication in the condition of higher nutrient load. Lake Taihu, Hongze and Caohu are already in eutrophic state. Eutrophic lakes are mainly distributed in the middle and lower reaches of Yangtze River and Yungui plateau. Lake eutrophication developed rapidly. Among the 34 lakes studied in 1970’s, most of lakes were in the mesotrophic status, mesotrophic water area accounted for 91.8%. With the nine year of 1978–1987 the area percentage of oligotrophic lakes decreased from 3.2% to 0.53%, and that of eutrophic lakes increased from 5.0% to 55.01%. Recent data showed 57.5% lakes were in eutrophic and hypertrophic status of the 40 surveyed lakes.
Eutrophic trend of Lake Taihu, Chaohu and Xuanwu in the region of the middle and lower reaches of Yangtze River was predicated using the ecological stress model. The results showed that in 2008 Lake Taihu, Chaohu and Xuanwu might be of eutrophication, eutrophication and hypertrophication, respectively if no control measurement is taken. Provided the pollution water treatment rate is 60% in 2030, approximately 30 billion ton pollution water would still be discharged directly in the lakes. Therefore, in 2030 the urban lakes in China might be eutrophication or hypertrophication, and most of the medium-sized lakes at the urban-rural fringe might be in eutrophication or hypertrophication. The famous five biggest freshwater lakes in China might be eutrophication if control countermeasures are taken as now.
Lake eutrophication has become a serious environmental problem in China. Based on the domestic and foreign experiences of the eutrophic control technologies, both nutrient pollution control and lake ecological restoration should be carried out and this may be the guidance for the eutrophic control of lakes in China.
The full-length cDNAs of six new O-superfamily conotoxins (CTX) were cloned and sequenced from Conus marmoreus native to Hainan in China South Sea using RT-PCR and 3′-RACE. Six novel conotoxin precursors encoded by these cDNAs consist of three typical regions of signal, pro-peptide and mature peptide. All the six toxin regions share a common O-superfamily cysteine pattern (C-C-CC-C-C, with three disulfide bridges). The predicted precursors are composed of 73–88 amino acids, and the predicted mature peptides consist of 26–34 amino acids. Phylogenetic analysis of new conotoxins from C. marmoreus from the present study and published homologue T-superfamily sequences from other Conus species was performed systematically. Patterns of sequence divergence for three regions of signal, pro-region and mature peptides, as well as Cys codon usage define the major O-superfamily branches and suggest how these separate branches arose. Percent identities of the amino acid sequences of the signal region exhibited high conservation, whereas the sequences of the mature peptides ranged from almost identical to highly divergent between inter- and intra-species. Notably, the diversity of the pro-region was also high with intermediate divergence between that observed in signal and toxin regions. Amino acid sequences and their mode of action (target) of previously identified conotoxins from molluscivorous C. marmoreus for the known conotoxins classes are discussed in detail. The data presented are new and should pave the way for chemical synthesis of these unique conotoxins for to allow determination of the molecular targets of these peptides, and also to provide clues for a better understanding of the phylogeny of these peptides. 相似文献
Current trophic status and trend of Chinese freshwater lakes were investigated in this study. The results showed that all lakes studied were commonly undergoing the eutrophica-tion process, water quality decreased and lake's ecosystem is being declined. Most of the urban lakes are facing serious eutrophication. Many medium-sized lakes are in metrophic or eutrophic status, some local water are even approaching the hypertrophic level. The famous five freshwater lakes in China have entered into eutrophication in the condition of higher nutrient load. Lake Taihu, Hongze and Caohu are already in eutrophic state. Eutrophic lakes are mainly distributed in the middle and lower reaches of Yangtze River and Yungui plateau. Lake eutrophication developed rapidly. Among the 34 lakes studied in 1970's, most of lakes were in the mesotrophic status, mesotrophic water area accounted for 91.8%. With the nine year of 1978-1987 the area percentage of oligotrophic lakes decreased from 3.2% to 0.53%, and that of eutrophic lakes increased from 5.0% to 55.01%. Recent data showed 57.5% lakes were in eutrophic and hyper trophic status of the 40 surveyed lakes. Eutrophic trend of Lake Taihu, Chaohu and Xuanwu in the region of the middle and lower reaches of Yangtze River was predicated using the ecological stress model. The results showed that in 2008 Lake Taihu, Chaohu and Xuanwu might be of eutrophication, eutrophication and hypertrophication, respectively if no control measurement is taken. Provided the pollution water treatment rate is 60% in 2030, approximately 30 billion ton pollution water would still be discharged directly in the lakes. Therefore, in 2030 the urban lakes in China might be eutrophication or hypertrophication, and most of the medium-sized lakes at the urban-rural fringe might be in eutrophication or hypertrophication. The famous five biggest freshwater lakes in China might be eutrophication if control countermeasures are taken as now. Lake eutrophication has become a serious environmental problem in China. Based on the domestic and foreign experiences of the eutrophic control technologies, both nutrient pollution control and lake ecological restoration should be carried out and this may be the guidance for the eutrophic control of lakes in China. 相似文献
Applied Microbiology and Biotechnology - We previously screened a whole-cell lipase EC 3.1.1.3 from the novel strain Aspergillus niger GZUF36, which exhibited 1,3-selectivity in the synthesis of... 相似文献
Coronary artery disease (CAD) is the most common heart disease worldwide. Association of CAD with variants in the myocyte enhancer factor 2A (MEF2A) gene, the first identified CAD-causing gene, has attracted special attention but the results are controversial. We aimed to evaluate this genetic association via a case-control study and meta-analysis.
Methodology/Principal Findings
We performed a case-control association study to investigate the relationship between variations in exon 11 of MEF2A gene and CAD in 1045 sporadic patients and 1008 controls enrolled angiographically among southern Chinese population, and then the data from this study were compared and discussed in a systematic review and meta-analysis with all available published studies on MEF2A gene and CAD. In total, eight variants were identified (21-bp deletion, CAG repeats, CCG repeats, a CCA deletion and four SNPs). No significant link was observed between the common (CAG)n polymorphism and CAD, whereas the rare 21-bp deletion was detected only in five affected individuals. The meta-analysis of (CAG)n polymorphism and CAD risk, including nine studies with 3801 CAD patients and 4020 controls, also provided no convincing evidence for the genetic association, even upon stratification by race (mainly Whites and Chinese). However, the 21-bp deletion was regarded as a potentially logical, albeit undetermined, candidate for CAD in the following systematic review.
Conclusions/Significance
Our findings failed to demonstrate a correlation between (CAG)n polymorphism with CAD, however, we concluded that the rare 21-bp deletion might have a more compelling effect on CAD than the common (CAG)n polymorphism, and MEF2A genetic variant might be a rare but specific cause of CAD/MI. 相似文献
Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an inhibitory molecule that plays a pivotal role in downregulating T-cell mediated immune responses. To determine the role of CTLA-4 in tumor immunity, and to validate previous results as well, we investigated four tag single nucleotide polymorphisms (SNPs) of CTLA-4 in a relatively large Chinese Han cohort from northeastern China. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 581 patients and 566 age-matched controls. Our data indicated that compared with the common genotype and allele of each SNP, the -1722 CC genotype and C allele showed an increased risk of breast cancer (P = 0.030, odds ratio (OR) = 1.457, 95% confidence internal (CI) 1.036-2.051; P = 0.024, OR = 1.214, 95% CI 1.026-1.436, respectively). The -1661 GG genotype and G allele were also associated with an increased risk of breast cancer (P = 0.018, OR = 1.396, 95% CI 1.058-1.843; P = 0.013, OR = 1.353, 95% CI 1.066-1.717, respectively). In the haplotype analysis, the CAAA haplotype showed a higher frequency in cases (P = 0.004), and this association remained significant after correcting the P value for multiple testing. Associations were shown between the SNPs of CTLA-4 and lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR) and P53 statuses. These results indicate that some SNPs in the CTLA-4 gene may affect the risk of breast cancer and show that some SNPs are associated with breast cancer characteristics in Han women in northeastern China. 相似文献