华西雨屏区香樟人工林土壤表层细根生物量和碳储量

2010年11月-2011年12月, 研究了华西雨屏区31年生香樟人工林土壤表层(0～30 cm)细根生物量及碳储量.结果表明: 香樟人工林土壤0～30 cm层细根总生物量(活根+死根)和碳储量的平均值分别为1592.29 kg·hm^-2和660.68 kg C·hm^-2,其中活细根贡献率分别为91.1%和91.8%.随着土壤深度的增加,香樟1～5级活细根和死细根的生物量及碳储量均显著减少;随着根序等级的升高,香樟活细根生物量及碳储量显著增加.香樟细根总生物量及碳储量均在秋季最高、冬季最低,死细根生物量及碳储量为冬季最高、夏季最低;1级根和2级根生物量及碳储量均在夏季最高、冬季最低,而3~5级根则为秋季最高、冬季最低.土壤养分和水分的空间异质性是导致细根生物量和碳储量变化的主要原因.     

新生与成年土拨鼠肝组织中部分差异表达的基因比较分析

目的新生土拨鼠感染土拨鼠肝炎病毒后,大部分发展为慢性肝炎,而成年土拨鼠感染后则多发生急性自限性肝炎。本实验目的就是寻找其肝组织中可能导致这种预后差异的关键基因。方法采用全基因组表达谱芯片技术,对比新生与成年小鼠肝组织基因表达差异,选取目的基因,再通过多个物种序列比对,设计简并引物,在土拨鼠肝组织eDNA中扩增对应基因,测序,再次设计引物,进行实时荧光定量PCR。结果与新生土拨鼠相比,成年土拨鼠肝细胞中与钙离子重吸收相关基因DNMl（Dynamin1）、DNM3（Dynamin3）及Prkcc（proteinkinaseC,gamma）表达率明显升高,分别上升2．65±0．25倍、1．90±0．34倍、2．94±0．54倍。结论在钙离子重吸收通路中,在两组小鼠肝脏中表达差异最明显的上述三个基因,在新生组与成年组土拨鼠之间也有明显差异。此类基因造成肝细胞内钙离子浓度的差别,间接影响其中肝炎病毒的复制。这种表达差异很可能是导致两个年龄段动物感染土拨鼠肝炎病毒后转归不同的原因之一。     

Heterologous expression and biochemical characterization of acetyl xylan esterase from Coprinopsis cinerea

Acetyl xylan esterase (AXE) from basidiomycete Coprinopsis cinerea Okayama 7 (#130) was functionally expressed in Pichia pastoris with a C-terminal tag under the alcohol oxidase 1 (AOX1) promoter and secreted into the medium at 1.5 mg l^?1. Its molecular mass was estimated to be 65.5 kDa based on the SDS-PAGE analysis, which is higher than the calculated molecular mass of 40 kDa based on amino acid composition. In-silico analysis of the amino acid sequence predicted two potential N-glycosylation sites. Results from PNGase F deglycosylation and mass spectrum confirmed the presence of N-glycosylation on the recombinant AXE with predominant N-glycans HexNAc₂Hex_9–16. The recombinant AXE showed best activity at 40 °C and pH 8. It showed not only acetyl esterase activity with a K_m of 4.3 mM and a V_max of 2.15 U mg^?1 for hydrolysis of 4-nitrophenyl acetate but also a butyl esterase activity for hydrolysis of 4-nitrophenyl butyrate with a K_m of 0.11 mM and V_max of 0.78 U mg^?1. The presence of two additional amino acid residues at its native N-terminus was found to help stabilize the enzyme against the protease cleavages without affecting its activity.     

Gonadotropin-Releasing Hormone Analog Cotreatment for the Preservation of Ovarian Function during Gonadotoxic Chemotherapy for Breast Cancer: A Meta-Analysis

Objective

To determine by meta-analysis whether gonadotropin-releasing hormone analog (GnRHa) cotreatment accompanying chemotherapy for breast cancer protects ovarian function.

Methods

Randomized controlled trials (RCTs) comparing GnRH cotreatment with chemotherapy alone in premenopausal women were collected by electronic and manual searches of Pubmed, MEDLINE (OVID), CENTRAL (The Coehrane Central Register of Controlled Trials), CBM, CNKI, VIP and Wanfang data bases. All the data was analyzed by Stata 11.2.

Results

Seven studies with a total of 677 participants met the inclusion criteria. The outcome of meta-analysis implied that, compared with adjuvant chemotherapy alone, the number of patients with resumption of spontaneous menstruation was statistically greater in the GnRH cotreatment patients (OR 2.83; 95% CI, 1.52–5.25).

Conclusions

Evidence from RCTs suggests a potential benefit of GnRH cotreatment with chemotherapy in premenopausal women, producing higher rates of spontaneous resumption of menses.     

Cx36 expression in the AII‐mediated rod pathway is activity dependent in the developing rabbit retina

Gap junctions are composed of connexin 36 (Cx36) and play a critical role in the rod photoreceptor signaling pathways of the vertebrate retina. Despite the fact that their connection and modulation in various rod pathways have been extensively studied in adult animals, little is known about the contribution and regulation of gap junctions to the development of the AII amacrine cell (AC)‐mediated rod pathway. Using immunohistochemistry and microinjection, this study demonstrates a steady increase in relative Cx36 protein expression in both plexiform layers of the rabbit retina at around the time of eye opening. However, immediately after eye opening, most Cx36 immunoreactive AII ACs show no gap junction coupling pattern to neighboring cells and it is not until the third postnatal week that AII cells begin to exhibit an adult‐like tracer‐coupling pattern. Moreover, studies using dark‐rearing and AMPA receptor blockade during postnatal development both revealed that relative levels of Cx36 immunoreactivity in AII ACs were increased when neural activity was inhibited . Our findings suggest that Cx36 expression in the AII‐mediated rod pathway is activity dependent in the developing rabbit retina . © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 473–486, 2016     

A transgenic plant cell‐suspension system for expression of epitopes on chimeric Bamboo mosaic virus particles

We describe a novel strategy to produce vaccine antigens using a plant cell‐suspension culture system in lieu of the conventional bacterial or animal cell‐culture systems. We generated transgenic cell‐suspension cultures from Nicotiana benthamiana leaves carrying wild‐type or chimeric Bamboo mosaic virus (BaMV) expression constructs encoding the viral protein 1 (VP1) epitope of foot‐and‐mouth disease virus (FMDV). Antigens accumulated to high levels in BdT38 and BdT19 transgenic cell lines co‐expressing silencing suppressor protein P38 or P19. BaMV chimeric virus particles (CVPs) were subsequently purified from the respective cell lines (1.5 and 2.1 mg CVPs/20 g fresh weight of suspended biomass, respectively), and the resulting CVPs displayed VP1 epitope on the surfaces. Guinea pigs vaccinated with purified CVPs produced humoral antibodies. This study represents an important advance in the large‐scale production of immunopeptide vaccines in a cost‐effective manner using a plant cell‐suspension culture system.