Population genetic structure of the medicinal plant Vitex rotundifolia in China: implications for its use and conservation

Vitexrotundifolia L.is an important plant species used in traditional Chinese medicine.For its efficient use and conservation,genetic diversity and clonal variation of V.rotundifolia populations in China were investigated using inter-simple sequence repeat markers.Fourteen natural populations were included to estimate genetic diversity,and a large population with 135 individuals was used to analyze clonal variation and fine-scale spatial genetic structure.The overall genetic diversity (GD) of V.rotundifolia populations in China was moderate (GD=0.190),with about 40% within-population variation.Across all populations surveyed,the average within-population diversity was moderate (P = 22.6%; GD = 0.086).A relatively high genetic differentiation (Gst=0.587)among populations was detected based on the analysis of molecular variance data.Such characteristics of V.rotundifolia are likely attributed to its sexual/asexual reproduction and limited gene flow.The genotypic diversity (D=0.992) was greater than the average values of a clonal plant,indicating its significant reproduction through seedlings.Spatial autocorrelation analysis showed a clear within-population structure with gene clusters of approximately 20 m.Genetic diversity patterns of V.rotundifolia in China provide a useful guide for its efficient use and conservation by selecting particular populations displaying greater variation that may contain required medicinal compounds,and by sampling individuals in a population at >20 m spatial intervals to avoid collecting individuals with identical or similar genotypes.     

GIT1 paxillin-binding domain is a four-helix bundle, and it binds to both paxillin LD2 and LD4 motifs

The G protein-coupled receptor kinase-interacting protein 1 (GIT1) is a multidomain protein that plays an important role in cell adhesion, motility, cytoskeletal remodeling, and membrane trafficking. GIT1 mediates the localization of the p21-activated kinase (PAK) and PAK-interactive exchange factor to focal adhesions, and its activation is regulated by the interaction between its C-terminal paxillin-binding domain (PBD) and the LD motifs of paxillin. In this study, we determined the solution structure of rat GIT1 PBD by NMR spectroscopy. The PBD folds into a four-helix bundle, which is structurally similar to the focal adhesion targeting and vinculin tail domains. Previous studies showed that GIT1 interacts with paxillin through the LD4 motif. Here, we demonstrated that in addition to the LD4 motif, the GIT1 PBD can also bind to the paxillin LD2 motif, and both LD2 and LD4 motifs competitively target the same site on the PBD surface. We also revealed that paxillin Ser(272) phosphorylation does not influence GIT1 PBD binding in vitro. These results are in agreement with the notion that phosphorylation of paxillin Ser(272) plays an essential role in regulating focal adhesion turnover.     

Repeated batch process for biological treatment of black liquor using brown-rot basidiomycete <Emphasis Type="Italic">Fomitopsis</Emphasis> sp. IMER2

A repeated batch operation is developed for the treatment of alkaline pulp black liquor, through a process of biological acidification precipitation of lignin using brown rot fungus Fomitopsis sp. IMER2. The results showed that COD and color removal of black liquor was dependent on the biomass concentration, pH decrease and initial COD. Based on these results, the repeated batch process was successfully carried out 12 times over 36 days in an air bubble column bioreactor. The average reduction of COD and color was approximately 40% and 70%, respectively.     

Amino acid composition of leaf,grain and bracts of japonica rice (<Emphasis Type="Italic">Oryza Sativa</Emphasis> ssp. <Emphasis Type="Italic">japonica</Emphasis>) and its response to nitrogen fertilization

Heat stress is one of the main abiotic stresses that limit plant growth. The effects of high temperature on oxidative damage, PSII activity and D1 protein turnover were studied in three wheat varieties with different heat susceptibility (CS, YN949 and AK58). The results showed that heat stress induced lower lipid peroxidation in AK58 and YN949 than CS, which was related to different changes of SOD, CAT, POD and H₂O₂. Similarly, AK58 and YN949 performed better PSII photochemical efficiency (F_v/F_m, ΦPSII and ETR) under high temperature, which was attributed to rapid synthesis and degradation of D1 protein. Moreover, higher expression of D1 protein turnover-related genes (PsbA, STN8, PBCP, Deg1, Deg2, Deg5, Deg8, FtsH1/5 and FtsH2/8) and SOD activity in AK58 and YN949 under normal conditions also established a basis for acclimatizing high temperatures, thereby alleviating PSII photoinhibition and reducing oxidative damage when exposed to heat stress.     

Calcium chloride improves photosynthesis and water status in the C<Subscript>4</Subscript> succulent xerophyte <Emphasis Type="Italic">Haloxylon ammodendron</Emphasis> under water deficit

It is important to reveal the mechanism of plants coping with heat stress, which results in a severe retardation in crop growth and development. Although Synaptotagmin A (SYTA) regulates the cell endocytosis and the plasma membrane reparation of Arabidopsis, its roles in heat resistance are not well understood. In this study, we obtained the new finding that SYTA is related to the heat resistance of Arabidopsis. In the SYTA overexpression strains, the germination rate of the seeds and the survival rate of the seedlings improved after heat shock treatment, and their degree of membrane peroxidation was reduced. However, syta mutant showed the opposite results. Meanwhile, the expressions of some heat stress signal pathway genes were higher in SYTA overexpression strains than that in wild-type strains, and were lower in syta mutant strains. These results suggested that SYTA responded positively to heat shock and was involved in the heat stress signal pathway.     

对人肠道病毒及其感染的再认识

长期以来,由于人肠道病毒种类众多,以隐性感染为主,引起的疾病症状从轻到重、表现多样,病原检测手段有限等原因,人们对人肠道病毒及其感染的基础与临床研究缺乏全面了解和认识。随着病毒学、分子生物学等技术的发展,特别是近年来各国频发人肠道病毒所致手足口病的流行,有必要对其及所致疾病再认识。     

Hela细胞HGPRT缺陷型细胞系构建

建立稳定的次黄嘌呤鸟嘌呤磷酸核糖转移酶(HGPRT)缺陷的Hela细胞系,为细胞融合相关研究和人源化单克隆抗体制备提供有利于筛选的亲本细胞。通过诱变剂N-甲基-N′-硝基-N-亚硝基胍(MNNG)对Hela细胞进行诱变,逐步提高培养基中6-巯基鸟嘌呤(6-TG)的浓度,筛选出对6-TG稳定耐受的细胞,在次黄嘌呤-氨基喋呤-胸腺嘧啶(hypoxanthine-aminopterin-thymidine,HAT)培养基中鉴定其敏感性,最后对筛选得到的Hela-HGPRT-进行生物学鉴定。在此基础上,将Hela-HGPRT-细胞系与人淋巴细胞融合,在HAT培养基中筛选杂交细胞。筛选得到了能够长期在含20μg/mL 6-TG培养基中生长的Hela-HGPRT-细胞,并且在HAT培养基中不能存活。Hela-HGPRT-细胞与人淋巴细胞成功融合,获得能够连续传代培养的杂交瘤细胞。经MNNG诱导和6-TG筛选,得到了稳定传代的Hela-HGPRT-细胞系,该细胞系可用于细胞融合相关研究。     

酵母表面展示脂肪酶合成己二酸二异辛酯

展示酶的酵母细胞既具有固定化酶的优点,又有制备简单、成本较低的特点.采用表面展示南极假丝酵母脂肪酶B (Candida antarctica lipase B,CALB)的毕赤酵母细胞催化合成己二酸二异辛酯(Diisooctyl adipate,DIOA),对该反应体系进行优化,并实现了初步工艺放大制备.经条件优化后,在10mL反应体系中,DIOA的产率可达85.0％.该工艺放大到200mL反应体系时,DIOA产率可达97.8％.经减压蒸馏,DIOA纯度可达到98.2％.该酵母表面展示脂肪酶在合成绿色润滑油己二酸二异辛酯中具有良好应用前景.