Supplemental L-arginine HCI augments bacterial phagocytosis in human polymorphonuclear leukocytes

That L-arginine (L-Arg) augments the host response to acute bacterial sepsis suggests that this amino acid intervenes early in the immune response, perhaps via the nitric oxide synthetase (NOS) pathway. The effect of L-Arg supplementation on in vitro phagocytosis of fluorescein-labeled, heat-killed Staphylococcus aureus by peripheral blood neutrophils (PMNs) from 12 normal human volunteers was studied. Separated PMNs were incubated for 2 h with labeled bacteria, with and without supplemental L-Arg, D-arginine, glycine, and/or the NOS inhibitors L-canavanine, aminoguanidine, or L-N^G-nitroarginine methyl ester. PMNs were fixed and extracellular fluorescence quenched with crystal violet. By flow cytometry and confocal microscopy, L-Arg supplementation was shown to result in a highly significant increase in PMN bacterial phagocytosis, the maximal effect being seen with L-Arg 380 μM and falling off with higher concentrations. This augmentation was completely abrogated by NOS inhibitors in molar excess, but inhibitors alone did not suppress phagocytosis below that of unsupplemented controls. Neither D-arginine nor glycine affected phagocytosis; the L-Arg effect was stereospecific and not related to utilization of L-Arg as an energy source. L-Arg supplementation significantly enhances bacterial phagocytosis in human neutrophils, perhaps by effects on cytoskeletal phenomena, and this appears to be mediated through NOS activity. Phagocytosis by nonspecific immune cells which intervene early in the response to sepsis is critically important, and beneficial effects of L-Arg on the clinical course of sepsis may be due at least in part to augmentation of phagocyte function. © 1996 Wiley-Liss, Inc.     

抗体固定化方法研究进展

在免疫分析和生物芯片中,抗原-抗体特异性结合被广泛应用,其中抗体的固定化是研发高效诊断和分离工具的关键环节。生物分子工程、材料化学与交联剂化学的进步极大地促进了抗体固定化技术的发展。 抗体可以通过物理吸附、共价偶联和亲和相互作用固定到不同类型的固相表面。 抗体固定化的目标是以一种正确的空间取向将抗体固定到固相表面,在完全保留抗体构象和活性的同时最大化抗原的结合能力,这对固相化抗体的分析性能至关重要。 对固定抗体到固相载体表面的各种最新方法进行了阐述,包括物理吸附法,通过羧基、氨基、巯基、糖基和点击化学的共价结合法以及基于生物亲和作用的固定法,并对固定化抗体的表征方法进行了归纳,最后对抗体固定化方法的发展方向进行了展望。     

水稻对叶瘟和穗瘟部分抗性的遗传分析

在一个水稻籼籼交重组自交系群体中,选用由感病株系构成的2个亚群体和2个不同的稻瘟病菌小种,进行了水稻对叶瘟部分抗性的QTL定位,还选用由感病而且抽穗期相近的株系构成的亚群体和另一个病菌小种,进行了水稻对穗瘟部分抗性的QTL定位,将病叶面积百分比(DLA)、病斑大小(LS)和病斑数(LN)作为对叶瘟部分抗性的性状,将病斑长度(LL)和孢子量(CA)作为对穗瘟部分抗性的性状。所构建的图谱包含168个标记。应用QTLMapper 1．01b,共检测到11个表现主效应的QTL和28对双因子互作,有3个表现主效应的QTL参与对同一性状的互作。QTL的主效应对单一性状的贡献率为4．7％～38．8％,而上位性效应对单一性状的贡献率为16．0％～51．7％,QTL的主效应对大多数性状的贡献率小于互作效应,表明互作效应对于部分抗性的重要作用。对穗瘟部分抗性的两个性状LL和CA,所检测到QTL总效应的贡献率分别达到70．6％和82．6％,表明由排除了主效抗病基因的感病株系组成的亚群体适合于进行部分抗性QTL定位。     

猪卵巢体外保存温度对卵母细胞染色质构型和成熟能力的影响

Most porcine oocytes used in studies on embryo biotechnology and the in vitro production of embryos are currently obtained from the ovaries of slaughtered gilts. The duration and temperature during ovary transportation and handling might, therefore, affect the recovery of culturable COCs, chromatin configuration and developmental competence of oocytes. The effects of ovary storage temperature on chromatin configuration and in vitro maturation of porcine oocytes were examined in this study. Ovaries collected from a slaughterhouse were stored in vitro for 8 h under different temperatures. The results showed that more culturable COCs were isolated from the ovares stored at 39℃ than that from ovaries stored at 31℃ or 20℃ and before storage. Thirty-one centidegree was the best storage temperature in terms of cumulus expansion, nuclear maturation and morphology of the first polar body after in vitro maturation culture. The ability of cumulus expansion was completely lost in COCs derived from ovaries stored at 39℃ for 8 hours. Ovary storage （at both 31℃ and at 20℃ ） increased the proportion of oocytes with the GVc configuration in which chromatin condensed into a single big clump at the nucleolus and the functional significance of this configuration needs further investigations [ Acta Zoologica Sinica 51 （5）： 919 923, 2005].     

Regulation of cell proliferation by fast Myosin light chain 1 in myoblasts derived from extraocular muscle, diaphragm and gastrocnemius

The extraocular muscle (EOM) suffers much less injury from Duchenne muscular dystrophy (DMD) than other skeletal muscles such as diaphragm and gastrocnemius. The present study was undertaken to test the hypothesis that differential expression of regulatory proteins between the EOM and other skeletal muscles is responsible for the observed difference in the sensitivity to DMD-associated damage. Protein expression in the tissue samples obtained from EOM, diaphragm or gastrocnemius of C57BL/6 mice was analyzed by two-dimensional gel electrophoresis and mass spectrometry. There were 35 proteins that were identified to be differentially expressed among different skeletal muscle tissues. Among the 35 proteins, a fast skeletal muscle isoform myosin light chain 1 (MLC1f) protein was further studied in relation to muscle cell proliferation. The EOM-derived myoblasts had much lower levels of MLC1f and higher rate of cell proliferation in contrast to the myoblasts derived from diaphragm or gastrocnemius, which displayed a higher expression of MLC1f along with a slow proliferation. Deletion of MLC1f using siRNA targeting MLC1f resulted in an increased rate of cell proliferation in the myoblasts. Cell cycle analysis revealed that MLC1f inhibited the transition of the cell cycle from the G1 to the S phase. Therefore, the present study demonstrates that MLC1f may negatively regulate proliferation of myoblasts through inhibition of the transition from the G1 to the S phase of the cell cycle. Low levels of MLC1f in myoblasts of EOM may ensure cell proliferation and enhance the repair process for EOM under the DMD disease condition, thus making EOM suffer less injury from DMD.     

马占相思叶片液汁碳同位素甄别率和水分利用效率

利用PMS压力室压取叶片液汁并借助稳定碳同位素质谱仪测定碳同位素比率,分析了马占相思(Acacia mangium )叶片液汁光合产物的甄别率(△)和估测了水分利用效率.结果表明:阴天马占相思林冠层日平均空气CO2 的碳同位素比率(δa)为-7.57‰±1.41‰,晴天则为-8.54‰±0.67‰;阴天叶片液汁的光合产物碳同位素比率(δp)日变化呈鞍型,而晴天则从早上至黄昏逐步降低;晴天δp与叶片/空气水汽压亏缺(D)明显呈负相关,阴天的δp变化相对较小;δp随叶片水势(ψ)降低而降低,显示水分胁迫引起δp降低;叶片液汁的D和经气体交换法获得的细胞胞间(Pi)和外界(Pa)CO2分压之比呈正相关,测定结果与理论上碳同位素相关扩散和生化分馏相一致.分析结果显示,田间马占相思空气CO2经气孔扩散的稳定同位素效应口a=4.6‰,有关Pi的净固定的稳定碳同位素效应6=28.2‰.认为液汁碳同位素甄别率是外围空气CO2进入光合产物的净甄别率,由叶片液汁△估测的水分利用效率与气体交换法所得结果相一致(R2=0.86,P＜0.001).本文所采用的叶片液汁光合产物测定即时△以及计算水分利用效率的方法,可减少田间条件下环境因素明显变化对水分和碳同位素的影响,该方法有助于进一步开展由植株至冠层扩展的碳和水分平衡的生理生态研究.     

基于SAFLP的我国常见索线虫科昆虫病原线虫亲缘关系分析

本研究建立并优化了索线虫科(Mermithidae)SAFLP体系,构建了我国常见索线虫科昆虫病原线虫6属11种/亚种的指纹图谱。采用EcoRⅠ和MseⅠ两种限制性内切酶单酶切,结果显示EcoRⅠ酶更适合作为索线虫科线虫SAFLP的内切酶。3个带有3个选择性碱基的EcoRⅠ引物进行扩增共得条带225个,片段大小为250～1 650 bp。通过NTsys-PC2.1软件计算了索线虫科6属11种/亚种的Nei-Li遗传距离(0.1980～034554)和相似系数,利用NTsys-PC2.1软件中的UPGMA方法构建其聚类图。索线虫科这6属11种/亚种从属级阶元可以分为两大类群：罗索属Romanomermis和八腱索属Octomyomermis聚为一支构成第一大类群;六索属Hexamermis与卵索属Ovomermis先聚在一起然后与多索属Agamermis聚在一起,再与两索属Amphimermis聚在一起构成第二大类群。在八腱索属和两索属中属内不同种/亚种间线虫采集地相距较近的其遗传距离较近。优化的索线虫科线虫SAFLP体系能够反映索线虫科线虫种属间的亲缘关系,并与形态学的研究结果基本相符,可以用于属种的分类和亲缘关系的研究。     

危型竹叶青蛇伤性DIC的救治

目的：通过比较单纯中医药治疗与抗蛇毒血清及中西医结合救治方法,观察竹叶青蛇伤性DIC患者的疗效。方法：用抗蛇毒血清、立止血及中西医结合的方法。从1996年8月至2002年9月,共收治危型竹叶青蛇伤性DIC患者25例。结果：25例均治愈。结论：抗蛇毒血清的早期应用是有效方法。抗五步蛇毒血清或抗蝮蛇毒血清和立止血合用,可以对竹叶青蛇毒的出血毒素和促凝毒性起较好的中和作用。     

大鼠肾虚自然流产模型的建立及相关因子的表达

目的建立大鼠肾虚自然流产模型,研究模型蜕膜细胞因子、协同刺激因子表达。方法雌性大鼠20只,雄性大鼠10只。将雌鼠与雄鼠按2∶1合笼,以阴道涂片出现大量精子为妊娠第1天,随机分为对照组、模型组每天灌服羟基脲450 mg/kg,第8天灌服米非司酮3.75 mg/kg,建立肾虚模型;统计饮食量、饮水量、肾、卵巢、胚胎直径指数;RT-PCR检查Th1型/Th2型细胞因子mRNA表达;流式细胞检测协同刺激因子CD80、CD86、CD28、CTLA-4表达。结果模型组动物饮食量、饮水量、体重增加量与对照组比较,第8天差异有显著性（P〈0.05）;胚胎直径指数显著减少（P〈0.01）;平均流产率显著升高（P〈0.01）;TNF-α、IFN-γ表达显著升高（P〈0.05）,IL-4I、L-10表达显著升高（P〈0.05）;CD80、CD86、CD28、CTLA-4显著性降低（P〈0.05）。结论灌服羟基脲与米非司酮可成功建立肾虚自然流产制模型。Th1型（TNF-αI、FN-γ）可能对妊娠有害,高表达有可能造成流产;Th2型（IL-4I、L-10）可能有利于妊娠,高表达维持妊娠。协同刺激因子CD80、CD86、CD28、CTLA-4表达与自然流产有关。     

尖吻蝮蛇蛇毒中一种新型酸性磷酯酶的纯化和表征

从尖吻蝮蛇蛇毒中, 通过嗜硫色谱、Sephadex G-75、Blue胶和POROS HQ20离子交换色谱,分离纯化得到纯组分AA-PLA₂-I,并证明其为新型酸性磷酸酯酶A₂ 经鉴定,该酶为分子量14.4 kD的单体蛋白,等电点5.66,不含中性糖基,N端序列为SLIQFETLIMKVVKK,其磷酸酯酶A2活性的最适温度和pH条件分别为50 ℃ 和 pH 10此外,该酶蛋白酶活性较弱,无出血毒性,但具有抗凝血活性,且其抗凝血活性耐热至70 ℃.