Comparisons of picophytoplankton abundance, size, and fluorescence between summer and winter in northern South China Sea

The abundance, size, and fluorescence of picophytoplankton cells were investigated during the summer (July-August of 2009) and winter (January of 2010) extending from near-shore coastal waters to oligotrophic open waters in northern South China Sea, under the influence of contrasting seasonal monsoons. We found that the median abundance of Prochlorococcus averaged over top 150 m decreased nearly 10 times in the winter compared to the summer in the whole survey area, while median abundance of Synechococcus and picoeukaryotes increased 2.6 and 2.4 folds, respectively. Vertical abundance profiles of picoeukaryotes usually formed a subsurface maximum during the summer with the depth of maximal abundances tracking the depth of nutricline, whereas their vertical distributions were more uniform during the winter. Size and cellular fluorescence of Prochlorococcus and Synechococcus usually increased with depth in the summer, while the size of picoeukaryotes was smallest at the depth of maximal abundances. Size, cellular fluorescence, and chlorophyll-to-carbon ratio of Prochlorococcus and Synechococcus in surface waters were generally higher in the winter than in the summer and onshore than offshore, probably resulting from different temperature, nutrient, and light environments as well as different ecotype compositions. Prochlorococcus cells were most abundant in warm and oligotrophic environments, while the abundance of Synechococcus and picoeukaryotes was the highest in waters with intermediate chlorophyll and nutrient concentrations. The distributional patterns of picophytoplankton groups are consistent with their specific physiology documented in previous studies and can be possibly predicted by environmental physical and chemical variables. (C) 2011 Elsevier Ltd. All rights reserved

Comparisons of picophytoplankton abundance, size, and fluorescence between summer and winter in northern South China Sea

The abundance, size, and fluorescence of picophytoplankton cells were investigated during the summer (July-August of 2009) and winter (January of 2010) extending from near-shore coastal waters to oligotrophic open waters in northern South China Sea, under the influence of contrasting seasonal monsoons. We found that the median abundance of Prochlorococcus averaged over top 150 m decreased nearly 10 times in the winter compared to the summer in the whole survey area, while median abundance of Synechococcus and picoeukaryotes increased 2.6 and 2.4 folds, respectively. Vertical abundance profiles of picoeukaryotes usually formed a subsurface maximum during the summer with the depth of maximal abundances tracking the depth of nutricline, whereas their vertical distributions were more uniform during the winter. Size and cellular fluorescence of Prochlorococcus and Synechococcus usually increased with depth in the summer, while the size of picoeukaryotes was smallest at the depth of maximal abundances. Size, cellular fluorescence, and chlorophyll-to-carbon ratio of Prochlorococcus and Synechococcus in surface waters were generally higher in the winter than in the summer and onshore than offshore, probably resulting from different temperature, nutrient, and light environments as well as different ecotype compositions. Prochlorococcus cells were most abundant in warm and oligotrophic environments, while the abundance of Synechococcus and picoeukaryotes was the highest in waters with intermediate chlorophyll and nutrient concentrations. The distributional patterns of picophytoplankton groups are consistent with their specific physiology documented in previous studies and can be possibly predicted by environmental physical and chemical variables. (C) 2011 Elsevier Ltd. All rights reserved

Gene Silencing of 4-1BB by RNA Interference Inhibits Acute Rejection in Rats with Liver Transplantation

The 4-1BB signal pathway plays a key role in organ transplantation tolerance. In this study, we have investigated the effect of gene silencing of 4-1BB by RNA interference (RNAi) on the acute rejection in rats with liver transplantation. The recombination vector of lentivirus that contains shRNA targeting the 4-1BB gene (LV-sh4-1BB) was constructed. The liver transplantation was performed using the two-cuff technique. Brown-Norway (BN) recipient rats were infected by the recombinant LVs. The results showed that gene silencing of 4-1BB by RNAi downregulated the 4-1BB gene expression of the splenic lymphocytes in vitro, and the splenic lymphocytes isolated from the rats with liver transplantation. LV-sh4-1BB decreased the plasma levels of liver injury markers including AST, ALT, and BIL and also decreased the level of plasma IL-2 and IFN-γ in recipient rats with liver transplantation. Lentivirus-mediated delivery of shRNA targeting 4-1BB gene prolonged the survival time of recipient and alleviated the injury of liver morphology in recipient rats with liver transplantation. In conclusion, our results demonstrate that gene silencing of 4-1BB by RNA interference inhibits the acute rejection in rats with liver transplantation

The Association of Serum L-Carnitine Concentrations with the Risk of Cancer in Chinese Adults with Hypertension

Background: The effect of serum L-carnitine (LC) concentrations on cancer risk remains unclear. This study aims to explore the association between serum LC and the risk of incident cancer. Methods: This is a case-control study, including 574 patients with incident cancer and 574 controls matched in a 1:1 ratio by age, sex, and residence, nested within the China H-Type Hypertension Registry Study (CHHRS). Conditional logistic regression analysis was used to assess the association of serum LC and incident cancer risk. Results: When LC was assessed as quartiles, compared with patients with low LC (Q1), patients in the highest quartile (Q4) had a 33% (OR = 0.67, 95% CI: 0.46 to 0.99), 52% (OR = 0.48, 95% CI: 0.23 to 0.99), and 39% (OR = 0.61, 95% CI: 0.38 to 0.99) decreased risk of overall, digestive system, and non-digestive system cancer in the adjusted models, respectively. In subgroup analyses, an inverse association of LC with cancer risk was observed in individuals who were overweight (obese), who never drink, who never smoke, and who were female. In the mediation analysis, serum trimethylamine-N-oxide (TMAO) concentrations did not mediate the reversed association of LC with cancer risk. Conclusions: This study showed that serum LC concentrations had a protective impact on overall, digestive system, and non-digestive system cancer risk

The combined effect of MTHFR C677T and A1298C polymorphisms on the risk of digestive system cancer among a hypertensive population

Abstract Background and purpose The enzyme methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in directing folate species towards nucleotide synthesis or DNA methylation. The MTHFR polymorphisms C677T and A1298C have been linked to cancer susceptibility, but the evidence supporting this association has been equivocal. To investigate the individual and joint associations between MTHFR C677T, A1298C, and digestive system cancer in a Chinese hypertensive population, we conducted a population-based case–control study involving 751 digestive system cancer cases and one-to-one matched controls from the China H-type Hypertension Registry Study (CHHRS). Methods We utilized the conditional logistic regression model to evaluate multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of digestive system cancer. Results The analysis revealed a significantly lower risk of digestive system cancer in individuals with the CT genotype (adjusted OR: 0.71; 95% CI 0.52, 0.97; P = 0.034) and TT genotype (adjusted OR: 0.57; 95% CI 0.40, 0.82; P = 0.003; P for trend = 0.003) compared to those with the 677CC genotype. Although A1298C did not show a measurable association with digestive system cancer risk, further stratification of 677CT genotype carriers by A1298C homozygotes (AA) and heterozygotes (AC) revealed a distinct trend within these subgroups. Conclusion These findings indicate a potential protective effect against digestive system cancer associated with the T allele of MTHFR C677T. Moreover, we observed that the presence of different combinations of MTHFR polymorphisms may contribute to varying susceptibilities to digestive system cancer

The association of serum betaine concentrations with the risk of new-onset cancers: results from two independent nested case-control studies

Abstract Evidence from epidemiologic studies on the association of circulating betaine levels with the incident risk of cancer has been inconsistent. We aimed to investigate the prospective association of serum betaine concentrations with the risk of cancer. We performed two, nested, case-control studies utilizing data from the “H-type Hypertension Prevention and Control Public Service Project” (HHPCP) and the China Stroke Primary Prevention Trial (CSPPT), with 2782 participants (1391 cancer cases and 1391 matched controls) in the discovery cohort, and 228 participants (114 cancer cases and 114 matched controls) in the validation cohort. Odds ratios (OR) of the association between betaine and cancer were calculated using conditional logistic regression models. There was an association between serum betaine as a continuous variable and total cancer (OR = 1.03, 95%CI = 0.99–1.07, p = 0.097). Among cancer subtypes, a positive association was found between serum betaine and the risk of lung cancer, and an inverse association was found with other cancers. Interestingly, a U-shaped association was observed between serum betaine and digestive cancers, with a turning point of 5.01 mmol/L for betaine (betaine < 5.01 mmol/L, OR = 0.82, 95%CI = 0.59–1.14, p = 0.228; betaine ≥ 5.01 mmol/L, OR = 1.08, 95%CI = 1.01–1.17, p = 0.036). In the validation cohort, a significant association between serum betaine as a continuous variable and total cancer (OR = 1.48, 95%CI = 1.06–2.05, P = 0.020) was also found. High serum betaine was associated with increased risk of total cancer and lung cancer, and a U-shaped association was found with the risk of digestive cancers, with a turning point at about 5.01 mmol/L

A Sensitive and Portable Double-Layer Microfluidic Biochip for Harmful Algae Detection

Harmful algal blooms (HABs) are common disastrous ecological anomalies in coastal waters. An effective algae monitoring approach is important for natural disaster warning and environmental governance. However, conducting rapid and sensitive detection of multiple algae is still challenging. Here, we designed an ultrasensitive, rapid and portable double-layer microfluidic biochip for the simultaneous quantitative detection of six species of algae. Specific DNA probes based on the 18S ribosomal DNA (18S rDNA) gene fragments of HABs were designed and labeled with the fluorescent molecule cyanine-3 (Cy3). The biochip had multiple graphene oxide (GO) nanosheets-based reaction units, in which GO nanosheets were applied to transfer target DNA to the fluorescence signal through a photoluminescence detection system. The entire detection process of multiple algae was completed within 45 min with the linear range of fluorescence recovery of 0.1 fM–100 nM, and the detection limit reached 108 aM. The proposed approach has a simple detection process and high detection performance and is feasible to conduct accurate detection with matched portable detection equipment. It will have promising applications in marine natural disaster monitoring and environmental care