斯氏线虫对进境原木上长林小蠹的防治试验

本文报道了斯氏线虫对进境原木上长林小蠹的生物防治试验.结果表明,斯氏线虫对长林小蠹的侵染力较强.通过毒力测定,斯氏线虫对长林小蠹3龄幼虫的LD50、LD99分别为21、432(条/头),而对蛹的LD50、LD99分别为12、230(条/头).在寄生强度测定中,斯氏线虫与长林小蠹3龄幼虫仅接触0.5h,每虫就可被侵入1.6条线虫,12h寄生的死亡率达到90%,24h寄生的死亡率为100%.斯氏线虫对长林小蠹表现出较高的致病性和寄生性.斯氏线虫在室内以浸泡法和淋施法防治长林小蠹的效果较好.     

缺铁胁迫下4种野生梨砧木介质pH值及根系Fe~(3+)还原酶活性的变化

以川梨、砂梨、豆梨和杜梨为材料,研究了在缺铁胁迫下培养介质的pH值和根系Fe3+还原酶活性的变化。结果表明,缺铁胁迫使4种砧木的介质pH值于处理的第2天就迅速降低,并且一直低于低铁和正常供铁处理;而低铁处理下,介质pH值在最初几天内反而高于正常处理,至4～5d之后才逐渐低于正常供铁处理;同时,NH4+-N对降低介质pH值和缓解缺铁症状有利。4种砧木的根系Fe3+还原酶活性都随供铁浓度的增加而不同程度的增大:无铁处理下,砂梨根系Fe3+的还原能力最小、杜梨最大;而在低铁和正常供铁条件下,砂梨和川梨的还原能力最强,杜梨次之,豆梨最小。还原酶大小与症状表现之间具有一致性。     

利用雄性不育两用系配制的辣椒一代杂种‘冀研8号’

 ‘冀研8号’是利用甜椒雄性不育两用系AB91-8为母本，以优良辣椒自交系L16-2为父本配制成的杂交一代辣椒新品种。该品种早熟，果实牛角形，商品性好，单果质量70 g，味辣，抗病毒病，较抗疫病，适宜华北地区春季塑料大拱棚和露地地膜覆盖栽培，产量49．6～63．6 t／hm 。     

半自然条件下几种赤眼蜂及品系对亚洲玉米螟卵寄生能力比较

在半自然条件(田间网罩)下,将人工饲养的玉米螟卵按4、8、16块/株3个处理分别固定在网罩内的玉米植株中上部叶片上,然后每网罩分别引入供试赤眼蜂20头,24 h后更换玉米螟卵块,连续3 d。7 d后调查供寄生的玉米螟卵被寄生率及羽化率。结果表明:在半自然条件下广赤眼蜂伊朗1-1品系虽寄生能力高于其他供试品系,但到第2、3天明显降低;玉米螟赤眼蜂北京6-2-2品系每天均维持一个较平稳的寄生能力,产卵量在时间上的分配比较分散,并在第2、3天显示出比其他品系较高的寄生潜能。广赤眼蜂伊朗1-1品系的卵块寄生数量可随卵块密度的增加而增加,而其他品系则在各处理密度下,寄生数量基本没有变化;从卵粒寄生率看,广赤眼蜂伊朗1-1和吉林1-2两个品系的寄生数量随卵块密度的增加而大幅度提高,其他品系增加幅度较小。     

Differential regulating effect on estrogen receptor α and β expression in female rat hippocampus and cortex regions between different types of estrogen regents

AIM: To study the regulatory effect two different estrogen reagents on expressions of estrogen receptor α and β in female rat hippocampus and cortex regions. METHODS: 12 cycles after ovariectomy, female rats were orally injected with premarin or progynova for 3 cycles before sacrificed. Semiquantitative RT-PCR was used to detect the ERs mRNA expression and SP immunohistochemistry was performed to measure the ERs protein distribution and expression. RESULTS: In premarin group, ER α mRNA levels in both hippocampus and cortex tissues decreased significantly compared with control. ER α protein level in hippocampus was lower than that in the control. However, ER α protein level in cortex had no statistical difference. ER β mRNA in the two regions and ER β protein in cortex had no statistical differences compared with control, while ER β protein level in hippocampus was higher than that in the control. In progynova group, both mRNA and protein levels of ER β increased significantly in the two regions compared with the control, and ER α mRNA level also increased in hippocampus, but ER α mRNA level in cortex and ER α protein levels in the above two regions showed no statistical differences. CONCLUSION: There were differential regulatory effects on ER α and ER β expression in female rat cognitive regions between the two different types of estrogen reagents, which may be one of the mechanisms of varied effects in different estrogen replacement therapy reagents.     

新扬州鸡IGF-1基因多态性与早期生长速度关系的研究

以150只非同胞新扬州鸡为材料，采用PCR—RFLP法检测了该基因5’调控区DNA序列多态性，并运用线性模型统计方法分析了多态性与初生重和12周龄体重的关系。结果显示：新扬州鸡IGF-1基因5、调控区自然存在两种不同DNA序列，经。PstⅠ酶切后出现3种基因型(“-／-”、“-／ ”、“ ／ ”)，基因型分布符合哈代一温伯格定律。各基因型个体的初生重、12周龄体重的最小二乘均数存在“-／-”＞“ ／-”＞“ ／ ”的趋势，且“-／-”型个体的12周龄体重显著高于“ ／ ”型个体(P＜0．05)。     

Monitoring response to aminobisphosphonate therapy in canine osteosarcoma using dual energy x‐ray absorptiometry (dexa)

Introduction: Palliative therapy is essential to improve the quality of life of dogs with osteosarcoma (OSA), when definitive therapy is not considered a valid option. Bisphosphonates, a novel class of antiosteoclastic drugs, are widely used in humans for several painful osteolytic conditions. Dual energy x‐ray absorptiometry (DEXA) is recognized as a reliable tool to measure bone mineral density (BMD), and to monitor treatment response to bisphosphonates in humans. A prospective evaluation of pamidronate, an injectable aminobisphosphonate, is ongoing in dogs with appendicular OSA. The potential value of DEXA for objective evaluation of BMD variations with palliative therapies is concurrently being assessed. Materials and Methods: Dogs with naturally occurring appendicular OSA treated with pamidronate constitute the patient population. A DEXA scan (QDR‐4500 W, Hologic, Bedford, MA) is performed on day 0 (baseline) and on every treatment day with pamidronate thereafter (every 28 days). For each dog, a whole body scan is performed, followed by a scan of the tumor, and contralateral normal bone. Three regions of interest are subsequently analyzed for BMD changes in tumor and normal bone. Statistical analysis was performed using Student t‐test and paired t‐tests, with significance being set at p < 0.05. Results: Nineteen dogs have been enrolled to date. Seven responders and 6 non‐responders have suitable data for analysis. A significant difference is observed (p = 0.04) between tumor BMD variations of responders and non‐responders at day 28 (mean variations +18.0% and ?4.6% respectively). The changes at day 28 are significant only in the responders (p = 0.038 vs p = 0.05 in non‐responders). When BMD of tumor and normal bone at day 84 is compared to day 0 in six responders, only tumor had a significant increase (p = 0.017 vs p = 0.279, respectively). Conclusions: Objective measurements of response to therapy are essential in pain palliation studies. Increased tumor bone BMD, as obtained by DEXA analysis, may correlate with subjective clinical improvement in pamidronate‐treated dogs with appendicular OSA.     

透明颤菌血红蛋白基因(vgb)在大肠杆菌中的高效表达

利用PCR技术将透明颠菌血红蛋白基因（vgb）克隆到融合表达载体pET28a，在大肠杆菌BL21（DE3）表达。重组蛋白在30℃诱导获得可溶表达。利用Ni^2＋亲和层析对重组蛋白进行了纯化，得到重组的透明颠菌血红蛋白，蛋白呈红色。实验现象显示重组蛋白与血红索相结合。紫外光区和可见光区波长扫描分析显示：蛋白粗提物和纯化后的血红蛋白在230nm和413nm都有强吸收峰，初步表明，尽管重组蛋白比天然蛋白多36个氨基酸，重组蛋白仍然具有生理活性。诱导后4h和6h的培养液氨基乙酰丙酸含量分别达到17mg／L和21mg／L。说明重组蛋白的表达明显促进了体内heme合成途径。     

四川猪链球菌Ⅱ型分离株生物学特性的初步研究

猪链球菌Ⅱ型是导致许多国家猪链球菌病的主要病原，自90年代晚期江苏发生猪链球菌Ⅱ型感染以来已成为我国引起人畜共患病的一种重要的新病原菌。最近在四川省部分地区发生了不明原因的猪源人畜共患病，且具有较高的死亡率。我们从病死猪的病料中成功分离到三株猪链球菌分离株，经革兰氏染色、生化试验、血清凝集试验和PCR鉴定，最终证实为猪链球菌Ⅱ型。通过对其毒力因子进行鉴定．结果发现MRP和EF均为阳性。进一步的药敏试验证实：分离菌株对氨苄青霉素、先锋霉素Ⅳ、羧苄青霉素、复方新诺明、头孢肤肟等抗菌药高度敏感。     

不同年限封育对黄土高原典型草原地上植被的影响

为了揭示自然恢复过程中植被动态变化规律,以黄土高原典型草原为研究对象,采用野外调查与室内分析相结合的方法,分析不同年限封育(0、5、15、23和32年)对草地植被特征、物种多样性和群落演替动态变化的影响。结果表明,随着封育年限的增加,枯落物量和厚度呈递增趋势,群落盖度呈先增加后降低趋势,群落密度呈递减趋势,地上生物量和禾草地上生物量均呈先增加后降低的趋势,且均在封育23年草地达到了峰值。不同年限的封育对Simpson多样性指数和Pielou均匀度指数影响不显著(P0.05)。地上植被的物种丰富度呈先增加后降低趋势,且在封育15年达到峰值。地上植被群落封育演替的一般模式为杂类草生长阶段→本氏针茅(Stipa bungeana)逐渐占优势阶段→本氏针茅稳定发展阶段。