田螺科五种螺的核型研究

以早期胚胎细胞为材料,用火焰干燥法制片,对分布于我国湖北省武汉市近郊的常见田螺科(Viviparidae)五种螺的核型进行了分析。结果:两种圆田螺的染色体数和国外报道的同一属的种类的一致。而三种环棱螺的染色体数,则较国外报道的另两种的少得多。在铜锈环棱螺的核型中,其m组的第一对和sm组的第四对染色体上,具有明显的随体,出现频率甚高。     

三羟异黄酮对HER-2/neu高表达乳腺癌细胞血管生成相关因子表达的影响

三羟异黄酮(genistein)是大豆中的一种非营养成分,其结构与黄酮化合物类似,能竞争性地与雌激素受体结合,故称之为植物雌激素(phytoestrogen)。它具有广泛的生物学作用,如抗肿瘤、抗病毒、抗真菌、抗氧化、抗突变、抗高血压、抗增生等,其中genistein抑制肿瘤的血管生成是当前研究的热点之一。肿瘤的血管生成是肿瘤进一步生长转移的基础,该过程受肿瘤细胞和血管内皮细胞分泌的血管生成相关因     

Effects of neuroactive steroids on myelin of peripheral nervous system

Peripheral nervous system (PNS) possess both classical (e.g. progesterone receptor, PR, androgen receptor, AR) and non-classical (e.g. GABA_A receptor) steroid receptors and consequently may represent a target for the action of neuroactive steroids. Our data have indicated that neuroactive steroids, like for instance, progesterone, dihydroprogesterone, tetrahydroprogesterone, dihydrotestosterone and 3-diol, stimulate both in vivo and in vitro (Schwann cell cultures), the expression of two important proteins of the myelin of peripheral nerves, the glycoprotein Po (Po) and the peripheral myelin protein 22 (PMP22). It is important to highlight that the mechanisms by which neuroactive steroids exert their effects on the expression of Po and PMP22 involve different kind of receptors depending on the steroid and on the myelin protein considered. In particular, at least in culture of Schwann cells, the expression of Po seems to be under the control of PR, while that of PMP22 needs the GABA_A receptor.

Because Po and PMP22 play an important physiological role for the maintenance of the multilamellar structure of the myelin of the PNS, the present observations might suggest the utilization of neuroactive steroids as new therapeutically approaches for the rebuilding of the peripheral myelin.     

Epithelial cadherin is present in bovine oviduct epithelial cells and gametes,and is involved in fertilization-related events

Fertilization is a calcium-dependent process that involves sequential cell–cell adhesion events of spermatozoa with oviduct epithelial cells (OECs) and with cumulus-oocyte complexes (COCs). Epithelial cadherin (E-cadherin) participates in calcium-dependent somatic cell adhesion; the adaptor protein β-catenin binds to the E-cadherin cytoplasmic domain and links the adhesion protein to the cytoskeleton. The study was conducted to immunodetect E-cadherin and β-catenin in bovine gametes and oviduct (tissue sections and OEC monolayers), and to assess E-cadherin participation in fertilization-related events. Epithelial cadherin was found in spermatozoa, oocytes, cumulus cells, and OEC. In acrosome-intact noncapacitated spermatozoa, E-cadherin was mainly localized in the apical ridge and acrosomal cap (E1-pattern; 84 ± 9%; mean ± standard deviation of the mean). After sperm treatment with heparin to promote capacitation, the percentage of cells with E1-pattern (56 ± 12%) significantly decreased; concomitantly, the percentage of spermatozoa depicting an E-cadherin staining pattern similar to E1-pattern but showing a signal loss in the acrosomal cap (E2-pattern: 40 ± 11%) increased. After l-α-lysophosphatidylcholine–induced acrosome reaction, E-cadherin signal was mainly localized in the inner acrosomal membrane (E3-pattern: 67 ± 22%). In IVM COC, E-cadherin was immunodetected in the plasma membrane of cumulus cells and oocytes, but was absent in the polar body. The 120 KDa mature protein form was found in protein extracts from spermatozoa, oocytes, cumulus cells, and OEC. β-Catenin distribution followed E-cadherin's in all cells evaluated. Epithelial cadherin participation in cell–cell interaction was evaluated using specific blocking monoclonal antibody DECMA-1. Sperm incubation with DECMA-1 impaired sperm–OEC binding (the number of sperm bound to OEC: DECMA-1 = 6.7 ± 6.1 vs. control = 29.6 ± 20.1; P < 0.001), fertilization with COC (% fertilized COC: DECMA-1 = 68.8 ± 10.4 vs. control = 90.7 ± 3.1; P < 0.05) or denuded oocytes (% fertilized oocytes: DECMA-1 = 57.0 ± 15.2 vs. control = 89.2 ± 9.8; P < 0.05) and binding to the oolemma (the number of sperm bound to oolemma: DECMA-1 = 2.2 ± 1.1 vs. control = 11.1 ± 4.8; P < 0.05). This study describes, for the first time, the presence of E-cadherin in bovine spermatozoa, COC, and OEC, and shows evidence of its participation in sperm interaction with the oviduct and the oocyte during fertilization.     

人参皂甙Rd预处理可减轻谷氨酸所致的PC12细胞损伤

目的:研究人参皂甙Rd(Ginsenoside Rd)预处理对谷氨酸所致PC12细胞损伤的影响。方法:将体外培养的PC12细胞分为3组,分别为对照组(Control)、谷氨酸损伤组(Glu)和人参皂甙Rd预处理组(Rd)。Control组细胞正常培养;Glu组细胞暴露于含10mM谷氨酸的DMEM培养基中损伤24 h;Rd组细胞经50μM的人参皂甙Rd预处理30 min后,在谷氨酸浓度为10 mM的DMEM培养基中损伤24 h。采用MTT检测细胞活力和乳酸脱氢酶(LDH)检测试剂盒检测LDH释放量;流式细胞仪检测胞内活性氧(ROS)水平;Western blot检测还原型谷胱甘肽蛋白(GSH)表达;专用试剂盒检测细胞内过氧化氢酶(CAT)和超氧化物歧化酶(SOD)含量,相差显微镜观测细胞形态。结果:50μM的人参皂甙Rd预处理30 min,可明显提高谷氨酸诱导的PC12细胞的活力,降低其LDH释放量、胞内ROS含量,并提高胞内GSH蛋白表达,增加CAT、SOD含量并改善细胞形态。结论:人参皂甙Rd预处理可减轻谷氨酸引起的PC12细胞损伤。     

关于三氧化二砷（As2O3）联合药物治疗肝癌的研究进展

实验与临床研究已证实,As2O3能有效治疗急性早幼粒细胞性白血病（APL）。在此基础上．As2O3抗肝癌作用的研究报告日益增多。研究表明As2O3的抗肝癌效力呈剂量一时间效应关系,但作用时间越长及药物浓度越大,As2O3的毒副作用越大。为实现As2O3低毒高效的抗肿瘤目的,联合用药引起关注。本文通过查阅94年至今国内外有关As2O3药物联合治疗肝癌的文献,对As2O3联合药物治疗肝癌予以综述。     

硝酸盐供应对玉米侧根生长的影响

以两个玉米(Zea mays L.)自交系478和Wu312为研究材料,采用琼脂培养方法,研究不同浓度NO-3对侧根生长的影响.结果表明,在外部浓度0.01～1.0mmol/L范围内,NO-3供应能显著增加侧根的长度及根生物量.但当NO-3供应超过1.0 mmo1/L后,侧根长度开始下降.当NO-3供应分别在超过5.0(Wu312)与10(478)mmol/L后,侧根密度显著下降.在10 mmol/LNO-3下,Wu312的侧根生长几乎完全被抑制.而478在20 mmol/L时,侧根密度仍可达到其最大值的30%(主根)～50%(胚根).植株地上部全氮及硝酸盐含量随NO-3供应的增加而升高,二者与侧根长度、侧根密度及冠根比的数学函数关系相同.     

Micelle‐enhanced spectrofluorimetric method for determination of sitagliptin and identification of potential alkaline degradation products using LC‐MS

A novel, quick, simple and highly sensitive spectrofluorimetric method was developed and validated for the determination of sitagliptin (SG) in its pharmaceutical formulations. The proposed method is based on investigation of the fluorescence spectral behavior of sitagliptin in an SDS micellar system. In an aqueous solution of phosphate buffer pH 4.0, the fluorescence intensity of SG in the presence of SDS was greatly enhanced, by 200%, i.e. twofold enhancement. The fluorescence intensity of SG was measured at 300 nm after excitation at 270 nm. The method showed good linearity in the range 0.03–10.0 µg/mL with a good correlation coefficient (r = 0.9998). The limits of detection and quantitation values were 5.31 and 16.1 ng/mL, respectively. The proposed method was successfully applied to the analysis of SG in its single and co‐formulated commercial tablets; the results were in good agreement with those obtained using a reference method. Application of the proposed method was extended to stability studies of SG after exposure to different forced degradation conditions according to the ICH guidelines, such as acidic, alkaline, thermal, photo‐ and oxidative stress. The chemical structure of certain potential degradation products (DPs) were investigated using LC‐MS. Copyright © 2013 John Wiley & Sons, Ltd.     

Age dependent sex allocation in the polygynous spotless starling

Theoretical and empirical evidence suggests that avian females are able to manipulate the offspring sex ratio at birth. Although mating with an attractive male may induce females to skew the sex ratio toward males, the balance between the benefits of producing attractive sons and the costs of competing with other females for mates could vary with female age, a possibility that had not been previously explored. In this paper we increment experimentally the attractiveness of males of the polygynous spotless starling (Sturnus unicolor) by adding green plants to their nests, a trait involved in courtship, and look for female age-differential effects on offspring primary sex ratio. Young and middle aged females produced more sons in experimental than in control nests, as expected, but old females showed the opposite tendency. To explain this novel result, we speculate that older females are limited to produce the most costly sex because the physiological drawbacks imposed by ageing reduce their ability to compete with younger ones for the non-shareable resources offered by males. We discuss that this evolutionary scenario may be widespread in avian polygynous systems.     

Akirin基因研究进展

Akirin是近来发现的在骨骼肌生长发育和免疫反应中具有重要作用的基因。简要综述了akirin基因与免疫反应、骨骼肌发育和再生、myostatin基因和NF-κB因子的关系,同时分析了禽类akirin2基因的研究进展,最后对akirin基因的应用前景也进行了简单探讨,以期为akirin基因在医学和畜牧业中的深入研究和应用提供参考。