Chlamydomonas reinhardtii Dangeard (Chlamydomonadales, Chlorophyceae) mutant with multiple eyespots

We have isolated a new Chlamydomonas reinhardtii Dangeard (Chlamydomonadales, Chlorophyceae) mutant with from one up to more than four eyespots cell^?1. It was designated mes (multiple eyespots)‐10 A wild‐type cell has a single eyespot, located under the chloroplast envelope, at a certain position near the cell's equator where the chloroplast envelope is in contact with the cell membrane. The eyespot(s) in mes‐10, however, are located at various positions on its chloroplast. The mes‐10 cells displayed negative phototaxis to 480–500 nm light. This behavior differed from that of a similar mutant, ptx4, which has been shown to have multiple eyespots and display no phototaxis (Pazour et al., J. Cell Biol. 1995; 131 : 427–40). Mes‐10 may retain a functional photoreceptor and a photosignal transduction system independently of its multiple eyespots. This mutant should be useful for studying how C. reinhardtii responds to light signals, as well as how eyespots are formed in the cell.     

Gax suppresses chemerin/CMKLR1‐induced preadipocyte biofunctions through the inhibition of Akt/mTOR and ERK signaling pathways

Adipose tissue is closely associated with angiogenesis and vascular remodeling. Chemerin is involved in inflammatory reaction and vascular dysfunction. However, the mechanisms of chemerin participating in vascular remodeling and whether Growth arrest‐specific homeobox (Gax) can effectively intervene it remain obscured. Here, 3T3‐F442A preadipocytes were cultured, injected into athymic mice to model fat pads, and treated respectively with Ad‐chemerin, Ad‐Gax, or specific inhibitors in vitro and in vivo. MTT, flow cytometry, Western blotting, and imunohisto(cyto)‐chemistry analyses showed that chemerin enhanced the expression of FABP4 and VEGF, activated Akt/mTOR and ERK pathways, increased the cell percent of S phase, decreased the percent of G0‐G1 phase and apoptotic cells, and augmented neovascular density in fat pads. Inversely, Gax suppressed the expression of these adipogenic and vasifactive markers and these signaling proteins, decreased the percent of S phase cells, and increased those of G0‐G1 phase and apoptotic cells, and reduced the neovascular density. Our results indicate that chemerin‐CMKLR1 activates Akt/mTOR and ERK pathways and facilitates preadipocyte proliferation, adipogenesis, and angiogenesis. Contrarily, Gax weakens the effect of chemerin on preadipocyte biofunctions.     

Conditional likelihood methods for haplotype-based association analysis using matched case-control data

Genetic epidemiologists routinely assess disease susceptibility in relation to haplotypes, that is, combinations of alleles on a single chromosome. We study statistical methods for inferring haplotype-related disease risk using single nucleotide polymorphism (SNP) genotype data from matched case-control studies, where controls are individually matched to cases on some selected factors. Assuming a logistic regression model for haplotype-disease association, we propose two conditional likelihood approaches that address the issue that haplotypes cannot be inferred with certainty from SNP genotype data (phase ambiguity). One approach is based on the likelihood of disease status conditioned on the total number of cases, genotypes, and other covariates within each matching stratum, and the other is based on the joint likelihood of disease status and genotypes conditioned only on the total number of cases and other covariates. The joint-likelihood approach is generally more efficient, particularly for assessing haplotype-environment interactions. Simulation studies demonstrated that the first approach was more robust to model assumptions on the diplotype distribution conditioned on environmental risk variables and matching factors in the control population. We applied the two methods to analyze a matched case-control study of prostate cancer.     

Improving consensus contact prediction via server correlation reduction

Background  

Protein inter-residue contacts play a crucial role in the determination and prediction of protein structures. Previous studies on contact prediction indicate that although template-based consensus methods outperform sequence-based methods on targets with typical templates, such consensus methods perform poorly on new fold targets. However, we find out that even for new fold targets, the models generated by threading programs can contain many true contacts. The challenge is how to identify them.     

干旱年份三江平原沼泽甲烷(CH4)排放及影响因子

为了研究淡水沼泽CH4排放的影响因子及其机制,在中国东北部的三江平原样地观测了CH4排放通量以及部分影响因子.结果表明,在2003年4～10月生长季内,毛果苔草沼泽CH4通量平均值为3.30 mg·m-2·h-1(最小值为0.65 mg·m-2·h-1,最大值为13.47 mg·m-2·h-1),低于小叶章沼泽化草甸CH4通量平均值4.91 mg·m-2·h-1(最小值为-0.12 mg·m-2·h-1,最大值为16.25 mg·m-2·h-1).在不同阶段,两种类型沼泽CH4通量有明显的变化,控制因子也不一样.4月份低温限制了CH4通量,两种类型沼泽差异很小.5～7月下旬,小叶章沼泽化草甸CH4通量显著高于毛果苔草沼泽CH4通量(P＜0.01),这种差异是由融冻作用造成的.8月份,植株密度和剖面中活性有机碳的浓度成为主要的影响因子,毛果苔草沼泽CH4通量比小叶章沼泽化草甸高.     

The microbial changes during the biological control of cucumber damping-off disease using biocontrol agents and reductive soil disinfestation

Cucumber damping-off disease mainly caused by Rhizoctonia solani leads to serious loss in agricultural production. In this study, the effective and environmentally friendly methods, using two biological agents combined with applying organic matter or reductive soil disinfestation (RSD), were performed to control the disease. Real-time PCR and MiSeq pyrosequencing were used to investigate the microbial community changes during the biocontrol process. The results showed that the applications of organic matter and antagonists (Ant) significantly decreased R. solani population and disease incidence, and increased soil microbial population and activity. However, antagonists application combined with RSD (RSD + Ant) behaved much better in nearly all aspects, and facilitated to maintain the population and activity of antagonists. Compared to the applications of organic matter and antagonists, the combination of RSD and antagonists changed soil microbial community structure to a larger extent. In conclusion, the applications of biocontrol agents and organic matter improved soil microbial community and decreased cucumber damping-off disease incidence, but the combination of RSD and the antagonists was a more promising method for the improvement of soil microbial community and the stable and successful control of the disease.     

Divergent Responses of Soil Fungi Functional Groups to Short-term Warming

Soil fungi fill pivotal ecological roles in biogeochemical processes, particularly dominating decomposition of lignin. Little is known, however, about the responses of different fungal groups to climate warming with respect to bacteria. In this study, using barcode pyrosequencing, we showed that short-term (15 months) of field exposure of an alpine meadow to warming (elevated 1 and 2 °C) did not markedly alter the overall soil fungal community structures and α-diversity on Tibetan Plateau, but the average β-diversity dramatically decreased in response to warming. However, soil respiration rates were stimulated in the growing season, which significantly (P?Ascomycota and rare taxa (relative abundance?Basidiomycota-affiliated members significantly increased, while Ascomycota showed a range of responses to warming. Collectively, we conclude that the fungal communities are resistant to short-term warming, though variations are observed in certain species and rare taxa. This report indicates that changes in a relatively small subset of the soil fungal community are sufficient to produce substantial changes in function, such as CO₂ efflux rates.