Characterization and expression of SLO1 potassium channels during spermatogenesis in Eriocheir sinensis

SLO1 potassium channels are pivotal to many aspects of spermatogenic cell. Experiments were conducted to assess physiology and function of SLO1 potassium channels in different developmental stages of spermatogenic cell in Eriocheir sinensis. First, the expression of SLO1 protein was examined via Western blot, RT‐PCR, immunohistochemistry and immunofluorescence assays. The results showed that the expression of the SLO1 protein was not uniform in the spermatogenic cells of E. sinensis. Second, whole‐cell patch clamp technique was used to record the potassium current of spermatogenic cells and to analyse the electrophysiological characteristics of the potassium channels with the aid of inhibitors. It is proved that the potassium current in E. sinensis germ cells is associated with intracellular Ca²⁺, and the calcium‐activated potassium channel mediated by SLO1 protein is mainly large‐conductance Ca²⁺‐activated K⁺ channels (BK_Ca). Based on these researches, the cDNA of SLO1 from testis was cloned and sequenced. The SLO1 protein contained domains bound to calcium ions, and the spatial structure formed by its tetramers constituted potassium channels. Phylogenetic analysis revealed that SLO1 was much closer to Scylla paramamosain than other examined species. Finally, iberiotoxin (IbTX) and CdCl₂ were used to inhibit the acrosome reaction (AR) induced by A23187 and to explore the role of SLO1 potassium channels in the AR of E. sinensis. The experimental results showed that SLO1 potassium channels were expressed in E. sinensis spermatogenic cells and played an important role in the AR of crab sperm (SP).     

桉树种间杂种的比较和选择研究

对 13个尾叶桉×细叶桉杂种、10个尾叶桉×赤桉杂种、1个尾叶桉× (尾叶桉×细叶桉 )杂种、1个尾叶桉种内控制授粉子代、5个尾叶桉母本的自由授粉子代和 1个尾叶桉×细叶桉F1自由授粉子代的比较研究表明 ,家系间树高、胸径和材积的差异均达 0 0 1显著水平。选择出优良杂种和子代 14个以及优良单株 12株。优良单株可以作为无性系比较试验的材料 ,优良杂种的优良单株可以用于建立下一世代的育种群体。这为优良杂种单株的无性系化和进一步的桉树杂交育种提供了有效的遗传材料。     

Gonadotropin‐Releasing Hormone Administration to Dairy Cows without a Corpus Luteum 4 Weeks after Calving Increases Reproductive Performance

This field study investigated whether the administration of a single dose of gonadotropin‐releasing hormone (GnRH) to dairy cows without a corpus luteum (CL) 4 weeks after calving can improve reproductive performance. Holstein dairy cows underwent ultrasonography to assess the presence of ovarian structures at 29.2 ± 5.2 days post‐partum, and cows were divided into two main groups based on the presence (CL group, n = 230) or absence (non‐CL group, n = 460) of a CL. The non‐CL group was further randomly divided into two subgroups based on the administration of GnRH (non‐CL GnRH group, n = 230) or no GnRH (non‐CL control group, n = 230). Subsets of cows from non‐CL control (n = 166) and non‐CL GnRH (n = 175) groups received a second ultrasonography at 44.5 ± 5.4 days post‐partum to assess CL formation. The percentage of cows with CL at the second ultrasonography was greater in the non‐CL GnRH group (70.9%) than in the non‐CL control group (53.0%, p = 0.0006). The hazard of the first post‐partum insemination by 150 days in milk (DIM) was higher in the CL group than in the non‐CL control group (hazard ratio [HR]: 1.36, p = 0.001). The probability of a pregnancy to the first insemination was higher in non‐CL GnRH (odds ratio [OR]: 1.50, p = 0.04) and CL groups (OR: 1.55, p = 0.03) compared to the non‐CL control group. Furthermore, the hazard of pregnancy by 210 DIM was higher in non‐CL GnRH (HR: 1.30, p = 0.01) and CL (HR: 1.51, p = 0.0001) groups than in the non‐CL control group. In conclusion, administration of GnRH to dairy cows without a CL 4 weeks after calving was associated with an increase in ovulation and improved reproductive performance.     

Cryopreservation of filefish (Thamnaconus septentrionalis Gunther, 1877) sperm

The present study examined the possibility of long‐term storage, by cryopreservation in liquid nitrogen, of the sperm of filefish (Thamnaconus septentrionalis). Changes in motility, survival rate, ultrastructure and fertilization rate of the sperm after freezing and thawing were tested. For selection of the immobilizing solution, artificial seawater (ASW) of 250, 350 and 450 mOsmol kg^?1 were tested. Sperm motility was significantly inhibited in 350 mOsmol kg^?1 ASW, and restored entirely after 100% ASW (1200 mOsmol kg^?1) was added. Two cryoprotectants, dimethyl sulphoxide and glycerol, were employed. The sperm was diluted at the ratio of 1:6 with the extenders, and frozen at a freezing rate of ?40°C min^?1 to ?100°C after equilibration for 10 min at room temperature, followed by plunging into liquid nitrogen. The highest post‐thawed sperm motility and survival rate were obtained with 5% glycerol. Afterwards, the effect of different freezing rates was examined using 5% glycerol as a cryoprotectant, and the rate of ?30°C min^?1 to ?100°C showed the best result.     

传染性脾肾坏死病毒_ConA和L_省略_对体外鳜的头肾淋巴细胞转化的影响

采用MTT颜色反应法研究传染性脾肾坏死病毒（ISKNV）、伴刀豆球蛋白A（concanavallin A,ConA)和脂多糖(lipopolysaccharide,LPS）在离体状态下对健康和ISKNV感染后存活30d或60d的鳜的头肾淋巴细胞转化的影响。结果表明，ConA和LPS能促进健康鳜头肾淋巴细胞的转化，而对感染后存活30d或60d的鳜头肾淋巴细胞没有作用；纯化的ISKNV对健康鳜头肾淋巴细胞没有促进淋巴细胞转化的作用，但对ConA的作用有抑制，对感染后存活的30d或60d的鳜头肾淋巴细胞，纯化的ISKNV有一定的促进转化的作用，感染存活的鳜头肾中有对ISKNV的免疫记忆性T细胞。另外，用建立的ISKNV PCR检测方法对健康和ISKNV感染后存活的鲜组织进行了检测，结果显示，健康鳜为阴性，而ISKNV感染后存活的鱼，头肾、后肾、脾脏和部分鱼的心脏为阳性。ISKNV在鳜体内形成潜伏感染。     

Effects of diet and sediment type on survival, growth and moulting of juvenile tiger crab, Orithyia sinica L.

This study investigated the effects of different types of diet and sediment on the growth parameters of juvenile tiger crab Orithyia sinica under laboratory conditions, focusing on survival, growth and moulting. In the first set of experiments, juvenile tiger crabs were reared with five different types of sediment, i.e., soft sand, coarse sand, soft sand mixed with coarse sand, mud or bare bottom. Soft sand resulted in not only the highest survival rate of 78% but also the best rate of growth and feed intake. Crabs reared with a mud substrate showed the worst results in these parameters. The intermoult period, however, was not affected by sediment types. In the second set of experiments, crabs were fed different types of diet to determine their effects on the same growth parameters. Diets were composed of different combinations with Manila clam (Ruditapes philippinarum), brine shrimp (Artemia nauplii), microencapsulated feeds and marine diatom (Chaetoceros gracilis). Survival and growth in crabs fed Manila clam as a diet component were significantly higher than in those on other diets. The highest survival and growth were achieved with a diet that included all four components. These results provide valuable information on the appropriate bottom substrates and diet types necessary for artificial mass culture of the tiger crab.     

大豆GmPIN2b调控根系响应低磷胁迫的功能研究

目的 研究生长素转运蛋白PIN基因家族在大豆Glycine max 根系适应低磷胁迫中的功能。方法 对大豆23个GmPIN家族成员进行进化树分析和表达模式分析,并进一步对GmPIN2b进行功能分析。结果 大豆23个GmPIN家族成员分散在7个不同的亚族,其中,GmPIN2a、GmPIN2b和GmPIN9a、GmPIN9d与拟南芥Arabidopsis thaliana的AtPIN2位于同一亚族。不同GmPIN家族成员在大豆中的组织表达定位及其受低磷调控的表达模式不同,其中,GmPIN2b在大豆根系中的表达水平在低磷胁迫6 d后显著上调,回补表达GmPIN2b能够部分恢复Atpin2突变体的表型。无论在低磷还是高磷条件下,回补表达GmPIN2b的转基因植株鲜质量和主根长均显著高于Atpin2突变体;而且回补表达GmPIN2b显著提高了Atpin2突变体在低磷条件下的一级侧根数,以及高磷条件下根系对重力的敏感性。结论 GmPIN2b在大豆根系形态建成响应低磷胁迫的过程中起重要的调控作用。     

兽医服务在食品安全中的作用

针对兽医服务的职能,结合兽医服务在食品安全中的作用,对兽医从传统到现在的职能转变作一综述。     

噻虫胺等七种杀虫剂对黄曲条跳甲的毒力

采用浸叶法测定了噻虫胺、高效氯氟氰菊酯等7种药剂及其混用对黄曲条跳甲的毒力及增效作用。结果显示:7种药剂中噻虫胺对黄曲条跳甲的毒力最高,LC50值为315.1 mg/L,其毒力倍数是呋虫胺的3.23倍;其次为噻虫嗪和高效氯氟氰菊酯,LC50值分别为473.1和543.1 mg/L。噻虫胺与高效氯氟氰菊酯按5∶5、4∶6、3∶7、2∶8和1∶9的质量比混用,其LC50值分别是215.6、307.1、334.1、232.6和240.7 mg/L,均表现为增效作用,其中2∶8和1∶9混用的共毒系数分别达203.9和210.5,增效最显著;噻虫胺与丁烯氟虫腈按5∶5、4∶6、3∶7、2∶8和1∶9的比例混用,其LC50值分别为409.2、356.9、338.1、402.4和392.6 mg/L,除5∶5混用表现为相加作用外,其余配比均表现为增效作用,其中1∶9混用共毒系数为182.1,增效显著;噻虫胺与杀虫单按5∶5、4∶6、3∶7、2∶8和1∶9的比例混用,其LC50值分别为479.4、540.0、454.8、737.0和878.7 mg/L,其中3∶7混用的共毒系数为127.9,有明显的增效作用,其余配比均表现为相加作用。噻虫胺与高效氯氟氰菊酯、丁烯氟虫腈、杀虫单混用增效作用明显,可以作为防治黄曲条跳甲的高效药剂。