[Responses of Nutrients and Chlorophyll a to Water Level Fluctuations in Poyang Lake].

As one of the few remaining lakes that are freely connected with the Yangtze River, Poyang Lake exhibits a unique aquatic ecology which is different from the disconnected lakes. In order to study the mechanism of limnological responses to water level fluctuations (WLFs), samples were collected weekly over 10 months from September 2011 to December 2012 in Xingzi and Duchang, and the effect of fluctuations in water level on nutrients and phytoplankton chlorophyll a (Chla) concentrations was investigated in Poyang Lake. Chla concentrations were strongly related to WLFs, with higher Chla concentrations in the higher water phase. The regression analysis indicated that Chla concentrations were significantly and positively correlated with water temperature (P<0.0001) and secchi depth (SD) (P<0.0001) but negatively correlated with total and inorganic nitrogen concentrations (TN,P<0.01; NOx-N,P<0.01; NH4+-N:P<0.05). SD and total and inorganic nitrogen concentrations were all significantly correlated with WLFs of Poyang Lake (SD,P<0.01; TN,P<0.0001; NOx-N:P<0.01; NH4+-N,P<0.0001). Two different water levels were identified in the lake by principal components analysis:the low water level with high nutrient values and the high water level with high water temperature, SD, and Chla values. These results supported the hypothesis that WLFs clearly exerted an overall impact on the growth of phytoplankton in Poyang Lake of the Yangtze River floodplain. WLFs affected the water transparency (expressed by SD), nutrients, and Chla concentrations of Poyang Lake, likely due to flush flood pulse, re-suspension of suspended matter, dilution effects, and human activities.

[Association between amino acid mutations in Gag protein and human leukocyte antigen class I alleles in human immunodeficiency virus-1 B' infected Han Chinese people].

OBJECTIVE: To explore the human leukocyte antigen (HLA)-associated mutations in Gag protein of B' clade (human immunodeficiency virus-1) HIV-1 infected Han Chinese people and evaluate the impact of HLA associated Gag mutations on the disease progression of HIV infection. METHODS: A total of 95 B' clade HIV-1 infected Han Chinese cases were recruited. The gag sequences were amplified from viral RNA and sequenced directly. HLA-I genotypes were detected with the assay of polymerase chain reaction-sequence specific primer (PCR-SSP). HLA-associated mutations were identified and the relationships between HLA-associated mutations and CD4+ T cell counts or plasma viral loads analyzed. RESULTS: Forty-seven kinds of mutations at 28 sites (15, 18, 26, 30, 34, 46, 62, 67, 81, 84, 90, 102, 118, 121, 122, 125, 146, 147, 173, 176, 252, 357, 374, 376, 437, 470, 471, 478) of Gag protein were significantly associated with particular HLA class I allelotypes (P < 0.05). Among which, 9 sites (26, 30, 81, 84, 125, 146, 147, 357, 437) were located within 13 known cytotoxic T-lymphocyte (CTL) epitopes or flanking regions. The number of HLA-associated mutations was significantly associated with both CD4 T cell counts (r = -0.318, P = 0.002) and viral loads (r = 0.360, P = 0.003). CONCLUSION: HLA-associated mutations may have a significant impact on HIV disease progression in B' clade HIV-1 infected Han Chinese population.

[Efficacy of anti-HIV treatment and drug-resistance mutations in some parts of China].

OBJECTIVE: To evaluate the Virologic and Immunologic efficacy of HAART on Chinese HIV/AIDS patients and to assess the impact of of HAART on drug resistance mutations. METHODS: Three cohorts of Liaoning, Jilin and Henan province received three different regimens for 6 months respectively. Regimen of Liaoning cohort comprised Efavirenz + Indinavir (EFV + IDV), regimen of Jilin cohort comprised Stavudine + Didanosine + Efavirenz (d4T + ddI + EFV) and regimen of Henan cohort comprised Stavudine + Didanosine + Nevirapine (d4T + ddI + NVP). Viral load, CD4(+) T cell count and drug resistance genotype were detected on the three cohorts before and after treatment. Partial HIV-1 pol genes encoding protease and 1 - 220 amino acid of reverse transcriptase were amplified by RT-PCR and then automatically sequenced. All sequences were compared with the data of Stanford HIV Drug Resistance Database to assess resistance mutations against reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs). RESULTS: During observation of 6 months, viral suppression to undetectable level and Elevated CD4(+)T cell count efficacy were achieved on partial Chinese HIV/AIDS patients in each of the three different regimens, even in some patients with rather low CD4(+)T cell count baseline. Before HAART, no primary mutations against PIs and RTIs were detected on the three cohorts, except one patient in Liaoning cohort. But after HAART, drug resistance mutations against RTIs occurred on each of the three cohorts. K103N is the most common mutation against NNRTIs, which can cause high-level resistance to each of the available NNRTIs. Y181C is another common mutation occurred in Henan cohort, which causes crossing drug resistance and multi-drug resistance to NNRTIs. In addition, intermediate level and low level resistance against NRTIs caused by K65R and L74V can also be found, but less commonly. CONCLUSION: Treatment naive Chinese HIV/AIDS patients were sensitive to HAART. Expected virologic and immunologic efficacy of HAART were achieved on Chinese HIV/AIDS patients, but after the introduce of HAART, the high prevalence of drug resistance mutations against NNRTIs and NRTIs, crossing drug resistance and multi-drug resistance reminded us to pay more attention to the drug resistance mutations detection, treatment standardization, and to avoid drugs wasting and prevent the prevalence of drug resistance strains.