影响纤维素类物质厌氧发酵产氢因素的研究

用预处理后的农作物水稻秸秆作为原料,进行厌氧发酵产氢,对产氢过程中的几种主要影响因素进行了实验研究。结果表明,起始pH值和反应温度对厌氧发酵产氢结果均有显著影响。在起始pH值为7,温度37℃时,可获得最大累计产氢量为122.1ml/g,在以玉米浆作为有机氮源的情况下,最大累计产氢量为141.2ml/g。     

Hepatitis B Virus (HBV) Surface Antigen Interacts with and Promotes Cyclophilin A Secretion: Possible Link to Pathogenesis of HBV Infection

Cyclophilin A (CypA), predominantly located intracellularly, is a multifunctional protein. We previously reported decreased CypA levels in hepatocytes of transgenic mice expressing hepatitis B virus (HBV) surface antigen (HBsAg). In this study, we found that expression of HBV small surface protein (SHBs) in human hepatoma cell lines specifically triggered CypA secretion, whereas SHBs added extracellularly to culture medium did not. Moreover, CypA secretion was not promoted by the expression of a secretion deficient SHBs mutant, suggesting a close association between secretion of CypA and SHBs. Interaction between CypA and SHBs was observed by using coimmunoprecipitation and glutathione S-transferase pull-down assays. Hydrodynamic injection of the SHBs expression construct into C57BL/6J mice resulted in increased serum CypA levels and ALT/AST levels, as well as the infiltration of inflammatory cells surrounding SHBs-positive hepatocytes. The inflammatory response and serum ALT/AST level were reduced when the chemotactic effect of CypA was inhibited by cyclosporine and anti-CD147 antibody. Furthermore, higher serum CypA levels were detected in chronic hepatitis B patients than in healthy individuals. In HBV patients who had received liver transplantation, serum CypA levels declined dramatically after the loss of HBsAg as a consequence of liver transplantation. Taken together, these results indicate that expression and secretion of SHBs can promote CypA secretion, which may contribute to the pathogenesis of HBV infection.Hepatitis B virus (HBV) infects more than 350 million people worldwide and is a major cause of chronic viral hepatitis and hepatocellular carcinoma (25). Three morphologically distinct forms of viral particles exist in the sera of HBV-infected patients, namely, the 22-nm-diameter spherical particles, tubular particles, and 42-nm-diameter virions (19). Strikingly, the subviral particles (spheres and tubules), containing only viral envelop glycoproteins and host-derived lipids, typically outnumber the virions by a factor of 1,000- to 10,000-fold (6, 11). There are three HBV envelop glycoproteins collectively known as HBV surface antigen (HBsAg), including the large (LHBs), middle (MHBs), and small (SHBs) surface proteins. Among them, SHBs is the most abundant viral envelop protein in virion and subviral particles. Although excess HBsAg subviral particles have been suggested to sequester the neutralizing antibody against HBV and contribute to a state of immune tolerance, thereby enabling the survival of infectious virions and leading to persistent infections (6, 27), the biological and pathological significance of the overproduction of HBsAg subviral particles still remains elusive.HBsAg has been proved extremely effective in inducing protective antibodies (anti-HBs) and thus has been used as the prophylactic vaccine. Thus far, most studies on HBsAg have focused on the development of hepatitis B vaccines (41), identification of HBsAg-interacting membrane proteins as potential host HBV receptors (9, 13), and characterization of the impact of naturally occurring HBsAg mutations on its antigenicity (12, 43). However, specific interactions between HBsAg and host intracellular factors have not been extensively studied.To address this issue, SHBs-secreting cell lines and lineages of HBV transgenic mice persistently expressing HBsAg were used in our previous studies (28, 34, 44). We found that the level of cyclophilin A (CypA) decreased markedly in the livers of HBsAg transgenic mice but increased significantly in their sera (44). CypA is a multifunctional cellular protein. It is the major binding protein for the immunosuppressive drug cyclosporine (Cs) (14) and exhibits peptidyl-prolyl cis-trans isomerase activity (35). Recently, it was found CypA played important roles in regulating inflammatory responses and viral infections. Regarding these newly recognized physiological functions, CypA was speculated to be involved in HBV infection. In the present study, the mechanism and clinical implications of elevated secretion of CypA induced by SHBs were explored in detail, including studies in cell cultures, hydrodynamic injected mouse models, and chronic hepatitis B patients. Our findings indicate that expression and secretion of SHBs can trigger the secretion of CypA, which may induce liver inflammation and contribute to the pathogenesis of HBV infection.     

Role of SHIP-1 in the adaptive immune responses to aeroallergen in the airway

Background

Th2-dominated inflammatory response in the airway is an integral component in the pathogenesis of allergic asthma. Accumulating evidence supports the notion that the phosphoinositide 3-kinase (PI3K) pathway is involved in the process. We previously reported that SHIP-1, a negative regulator of the PI3K pathway, is essential in maintaining lung immunohomeostasis, potentially through regulation of innate immune cells. However, the function of SHIP-1 in adaptive immune response in the lung has not been defined. We sought to determine the role of SHIP-1 in adaptive immunity in response to aeroallergen stimulation in the airway.

Methodology/Principal Findings

SHIP-1 knockout (SHIP-1^−/−) mice on BALB/c background were immunized with ovalbumin (OVA) plus aluminum hydroxide, a strong Th2-inducing immunization, and challenged with OVA. Airway and lung inflammation, immunoglobulin response, Th2 cytokine production and lymphocyte response were analyzed and compared with wild type mice. Even though there was mild spontaneous inflammation in the lung at baseline, SHIP-1^−/− mice showed altered responses, including less cell infiltration around the airways but more in the parenchyma, less mucus production, decreased Th2 cytokine production, and diminished serum OVA-specific IgE, IgG1, but not IgG2a. Naïve and OVA sensitized SHIP-1^−/− T cells produced a lower amount of IL-4. In vitro differentiated SHIP-1^−/− Th2 cells produced less IL-4 compared to wild type Th2 cells upon T cell receptor stimulation.

Conclusions/Significance

These findings indicate that, in contrast to its role as a negative regulator in the innate immune cells, SHIP-1 acts as a positive regulator in Th2 cells in the adaptive immune response to aeroallergen. Thus any potential manipulation of SHIP-1 activity should be adjusted according to the specific immune response.     

亚硝基胍诱变选育林肯霉素高产菌株

以林肯链霉菌９４７－８（Ｓｔｒｅｐｔｏｍｙｃｅｓｌｉｎｃｏｌｎｅｎｓｉｓ９４７－８）为出发菌株（产林肯霉素９４０γ／ｍｌ）。采用孢子热处理方法处理出发菌株孢子,得到变异株９４７－８ｓ,产林肯霉素１０８０γ／ｍｌ。对９４７－８ｓ菌株进行ＮＴＧ诱变处理,得变异株９４７－８ｘ,产林肯霉素为１２１８γ／ｍｌ,且生产能力稳定。     

基于按摩的电刺激器的设计

目的设计一种基于中医按摩的电刺激仪器——将产生的电刺激信号通过中医的按摩手法给患者按摩。方法研究采用STC89C58RD＋单片机作为控制器,采用LCD点阵液晶显示作为可视化的提示工具,采用4＊4矩阵键盘作为输入控制接口,采用变压器作为电刺激信号升压器件。结果研究实现了预期目标,用户可通过LCD提示输入控制点刺激信号强度的按键,单片机处理后输出相应的脉冲波形,进而触发生成用于按摩的电刺激信号。结论对51单片机开发应用,实现了输入不同的频率信息,产生不同强度的电刺激信号,使人感觉不同程度的麻刺激,能够用于治疗和保健。     

Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning

Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.     

High-resolution mapping of the brown planthopper resistance gene Bph6 in rice and characterizing its resistance in the 9311 and Nipponbare near isogenic backgrounds

Brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most destructive insect pests of rice. Exploring resistance genes from diverse germplasms and incorporating them into cultivated varieties are critical for controlling this insect. The rice variety Swarnalata was reported to carry a resistance gene (designated Bph6), which has not yet been assigned to a chromosome location and the resistance mechanism is still unknown. In this study, we identified and mapped this gene using the F₂ and backcrossing populations and characterized its resistance in indica 9311 and japonica Nipponbare using near isogenic lines (NILs). In analysis of 9311/Swarnalata F₂ population, the Bph6 gene was located on the long arm of chromosome 4 between the SSR markers RM6997 and RM5742. The gene was further mapped precisely to a 25-kb region delimited between the STS markers Y19 and Y9; and the distance between these markers is 25-kb in Nipponbare genome. The Bph6 explained 77.5% of the phenotypic variance of BPH resistance in F₂ population and 84.9% in BC₂F₂ population. Allele from Swarnalata significantly increased resistance to the BPH, resulted in a reduced damage score. In characterization of Bph6-mediated resistance, the BPH insects showed significant preference between NIL-9311 and 9311 in 3 h and between NIL-NIP and Nipponbare in 120 h after release. BPH growth and development were inhibited, and the insect’s survival rates were lower on Bph6-NIL plants, compared with the parents 9311 and Nipponbare. The results indicate that the Bph6 exerted prolonged antixenotic and antibiotic effects in Bph6-NIL plants, and NIL-9311 plants showed a quicker and stronger effect toward BPH than NIL-NIP plants.     

Promoter diversity in multigene transformation

Multigene transformation (MGT) is becoming routine in plant biotechnology as researchers seek to generate more complex and ambitious phenotypes in transgenic plants. Every nuclear transgene requires its own promoter, so when coordinated expression is required, the introduction of multiple genes leads inevitably to two opposing strategies: different promoters may be used for each transgene, or the same promoter may be used over and over again. In the former case, there may be a shortage of different promoters with matching activities, but repetitious promoter use may in some cases have a negative impact on transgene stability and expression. Using illustrative case studies, we discuss promoter deployment strategies in transgenic plants that increase the likelihood of successful and stable multiple transgene expression.