Testosterone increases neurotoxicity of glutamate in vitro and ischemia-reperfusion injury in an animal model.

Increasing evidence has demonstrated striking sex differences in the outcome of neurological injury. Whereas estrogens contribute to these differences by attenuating neurotoxicity and ischemia-reperfusion injury, the effects of testosterone are unclear. The present study was undertaken to determine the effects of testosterone on neuronal injury in both a cell-culture model and a rodent ischemia-reperfusion model. Glutamate-induced HT-22 cell-death model was used to evaluate the effects of testosterone on cell survival. Testosterone was shown to significantly increase the toxicity of glutamate at a 10 microM concentration, whereas 17beta-estradiol significantly attenuated the toxicity at the same concentration. In a rodent stroke model, ischemia-reperfusion injury was induced by temporal middle cerebral artery occlusion (MCAO) for 1 h and reperfusion for 24 h. To avoid the stress-related testosterone reduction, male rats were castrated and testosterone was replaced by testosterone pellet implantation. Testosterone pellets were removed at 1, 2, 4, or 6 h before MCAO to determine the duration of acute testosterone depletion effects on infarct volume. Ischemic lesion volume was significantly decreased from 239.6 +/- 25.9 mm(3) in control to 122.5 +/- 28.6 mm(3) when testosterone pellets were removed at 6 h before MCAO. Reduction of lesion volume was associated with amelioration of the hyperemia during reperfusion. Our in vitro and in vivo studies suggest that sex differences in response to brain injury are partly due to the consequence of damaging effects of testosterone.     

肾综合征出血热纯化疫苗的SDS-PAGE分析

为了证明蛑综合征出血热纯化疫苗的主要成分坦病毒蛋白,采用出血热纯化疫苗经浓缩后进行SDS－PAGE和Western-blotting分析。结果 经SDS－PAGE显示,肾综合征出血热纯化疫苗有三条蛋白带,分子量分别约为70kD、55kD和50kD,与汉坦病毒三种结构蛋白（糖蛋白G1、G2和核蛋白NP）的分子量相符;经Western-blotting显示,分子量50kD的蛋白带反应阳性,分子量70kD和55kD的蛋白带无反应,认定出血热纯化疫苗的主要成分为汉坦病毒蛋白,主要由G1、G2和NP三种结构蛋白构成。     

Cytotoxic function of xylanase VdXyn4 in the plant vascular wilt pathogen Verticillium dahliae

Phytopathogen xylanases play critical roles in pathogenesis, likely due to their ability to degrade plant structural barriers and manipulate host immunity. As an invader of plant xylem vessels, the fungus Verticillium dahliae is thought to deploy complex cell wall degrading enzymes. Comparative genomics analyses revealed that the V. dahliae genome encodes a family of six xylanases, each possessing a glycosyl hydrolase 11 domain, but the functions of these enzymes are undetermined. Characterizing gene deletion mutants revealed that only V. dahliae xylanase 4 (VdXyn4) degraded the plant cell wall and contributed to the virulence of V. dahliae. VdXyn4 displayed cytotoxic activity and induced a necrosis phenotype during the late stages of infection, leading to vein and petiole collapse that depended on the enzyme simultaneously localizing to nuclei and chloroplasts. The internalization of VdXyn4 was in conjunction with that of the plasma membrane complexLeucine-rich repeat (LRR)-receptor-like kinase suppressor of BIR1-1 (SOBIR1)/LRR-RLK BRI1-associated kinase-1 (BAK1), but we could not rule out the possibility that VdXyn4 may also act as an apoplastic effector. Immune signaling (in the SA–JA pathways) induced by VdXyn4 relative to that induced by known immunity effectors was substantially delayed. While cytotoxic activity could be partially suppressed by known effectors, they failed to impede necrosis in Nicotiana benthamiana. Thus, unlike typical effectors, cytotoxicity of VdXyn4 plays a crucial intracellular role at the late stages of V. dahliae infection and colonization, especially following pathogen entry into the xylem; this cytotoxic activity is likely conserved in the corresponding enzyme families in plant vascular pathogens.

By virtue of its cytotoxic activity, Verticillium dahliae Xylanase induces necrosis, leading to vein and petiole collapse that depends on the enzyme simultaneously localizing to nuclei and chloroplasts.     

SSR分子标记在作物遗传育种中的应用

SSR(simple sequence repeat)是建立在PCR技术上的一种广泛应用的分子标记,具有含量丰富、多态性高、共显性等优点。本文简要介绍了SSR分子标记技术的原理和特点,重点介绍了SSR分子标记技术在作物遗传育种中的应用,主要在作物遗传多样性、基因定位、分子辅助标记、遗传图谱构建、品种鉴定和纯度鉴定等方面进行阐述。     

Microcalorimetric Study on the Effect of Ce<Superscript>3+</Superscript> on <Emphasis Type="Italic">Halobacterium halobium</Emphasis> R1

A microcalorimeric technique was used to evaluate the influence of rare earths Ce³⁺ on Halobacterium halobium R1 growth. By means of TAM air Thermal Activity Monitor, the thermogenic curves of H. halobium R1 growth were obtained. To analyze the results, the growth rate constant k and IC₅₀ were calculated, indicating that the values of k are linked to the concentration of Ce³⁺. The growth rate constant k of H. halobium R1 decreased gradually in the low concentration; thus, rare earths restrained the growth of H. halobium R1. On the contrary, as the concentration of Ce³⁺ became higher, the value of k for H. halobium R1 increased gradually, which showed Ce³⁺ stimulated the growth of H. halobium R1. When the concentration of rare earths became much higher, the value of k for H. halobium R1 also decreased, and the growth of H. halobium R1 was restrained totally in the end. By using transmission electron microscopy (TEM), it was observed that the transforming of H. halobium R1 in the different concentrations of Ce³⁺ confirmed the results derived from microcalorimetry. According to the thermogenic curves and TEM photos of H. halobium R1 under various conditions, it showed that there was some special effect about the interaction between rare earths and H. halobium R1 growth.     

芽胞杆菌Q13和Q14在猕猴桃叶面的定殖及其对叶面菌群的影响

为了进一步明确芽胞杆菌Q13、Q14菌株对猕猴桃叶枯病的生防作用,分别对芽胞杆菌Q13、Q14菌株在猕猴桃叶面上的定殖作用及其对叶面其他微生物种类和数量的影响进行了考察。结果表明,在田间条件下,芽胞杆菌Q13、Q14能在猕猴桃叶面定殖,但随时间的变化呈下降趋势;在无降雨等恶劣天气影响的情况下,该菌能在猕猴桃叶面有效定殖8 d左右,8 d后叶面检测到的Q13、Q14菌株的菌量为4.5×106cfu/g成熟叶。与未喷施菌剂的猕猴桃叶面菌群对比,喷施菌剂后的猕猴桃叶面细菌种类多了芽胞杆菌属(Bacillus subtilis),少了条件致病菌不动杆菌属(Acinetobacter soli);真菌在数量上癣囊腔菌(Plectosphaerellacucumerina)、Pseudozyma flocculosa和米曲霉菌(Aspergillus oryzae)增加了,泡状莫氏黑粉菌(Moesziomyces bullatus)和尖孢镰刀菌(Fusarium oxysporum)减少了。     

Single nucleotide polymorphisms of myostatin gene in Chinese domestic horses

The myostatin gene (MSTN) is a genetic determinant of skeletal muscle growth. Single nucleotide polymorphisms (SNP) in MSTN are of importance due to their strong associations with horse racing performances. In this study, we screened the SNPs in MSTN gene in 514 horses from 15 Chinese horse breeds. Six SNPs (g.26 T > C, g.156 T > C, g.587A > G, g.598C > T, g.1485C > T, g.2115A > G) in MSTN gene were detected by sequencing and genotyped using PCR-RFLP method. The g.587A > G and g.598C > T residing in the 5′UTR region were novel SNPs identified by this study. The g.2115A > G which have previously been associated with racing performances were present in Chinese horse breeds, providing valuable genetic information for evaluating the potential racing performances in Chinese domestic breeds. The six SNPs together defined thirteen haplotypes, demonstrating abundant haplotype diversities in Chinese horses. Most of the haplotypes were shared among different breeds with no haplotype restricted to a specific region or a single horse breed. AMOVA analysis indicated that most of the genetic variance was attributable to differences among individuals without any significant contribution by the four geographical groups. This study will provide fundamental and instrumental genetic information for evaluating the potential racing performances of Chinese horse breeds.     

中频交变电流抑制肿瘤细胞的体外增殖

目的:初步探究新型物理治疗技术中频交变电流对肿瘤细胞和正常细胞体外存活率的影响;设置不同实验参数(频率、电流、时间),观察影响效果;针对实验结果,分析中频交变电流抑制肿瘤细胞体外增殖的可能机制。方法:将对数生长期的细胞悬液接种于24孔培养板,贴壁后(24 h)施加不同参数的中频电流刺激,噻唑蓝(MTT)法检测细胞存活率;以人乳腺癌细胞MCF-7为例,观察中频交变电流对细胞生存环境温度和pH的影响,Annexin V-FITC/PI双染法流式细胞术定量检测细胞凋亡/死亡情况,扫描电子显微镜和透射电子显微镜观察细胞结构变化。结果:中频交变电流能降低肿瘤细胞的体外存活率,诱导其凋亡,但不影响正常细胞(L929)存活率;MCF-7细胞体外实验最适参数是100 kHz,50 mA,每天30 min;电刺激后MCF-7细胞表面微绒毛减少,细胞线粒体肿胀,有多泡体及溶酶体形成。结论:中频交变电流能抑制肿瘤细胞增殖,但不影响正常细胞(L929);抑制效果和电刺激的频率、电流和时间有关;抑制机制可能是中频交变电流能够诱导细胞凋亡,影响细胞膜表面蛋白功能,但不影响细胞生存环境。中频交变电流抑制肿瘤体外增殖为实体瘤等增生性疾病的治疗提供了新的思路。     

NaCI胁迫下不同南瓜幼苗耐盐性研究

研究了300mmol／L NaCl胁迫对19个不同类型南瓜品种幼苗盐害指数、电解质渗透率、脯氨酸及可溶性糖含量的影响。结果表明,随NaCl胁迫时间延长,南瓜幼苗盐害指数、电解质渗透率、脯氨酸含量和可溶性糖含量均呈升高趋势。盐害指数和电解质渗透率能较好反映南瓜幼苗的耐盐性,可作为南瓜品种耐盐性的筛选指标。在NaCl胁迫下,青栗南瓜（Q1）表现出很强的耐盐性,黑蛮南瓜（H2）和黑籽南瓜（H3）为盐敏感品种,而其他为耐盐性中等品种。