In vitro effects of four tropical plants on three life-cycle stages of the parasitic nematode, Haemonchus contortus

Alcoholic extracts of four tropical plants (Zanthoxylum zanthoxyloides, Newbouldia laevis, Morinda lucida and Carica papaya) were screened in vitro for potential anti-parasitic effects against eggs, infective larvae and adult Haemonchus contortus. Significant effects were obtained with all four plants but differences were observed depending on the parasitic stage. The effects of the four plant extracts were similar on egg hatching and were dose dependent. In contrast, no dose-response relationship was found for infective larvae and adult worms, although more potent effects were usually observed with the highest concentrations. Using a larval inhibition migration test, extracts of fagara (Z. zanthoxyloides) were found to be less active against Haemonchus infective larvae than were the other plants. N. laevis was found to be highly and rapidly effective against adult worms. Overall, these in vitro results suggest that these four plants, traditionally used by small farmers in Western Africa, do possess anti-parasitic properties. These effects remain to be confirmed through in vivo studies.     

植物生长调节剂对梨试管苗培育及移栽的影响

BAP、IBA和GA_3对梨砧木BP10030茎尖外殖体的成活率没有明显影响,但0.1mg·1~(-1)GA_3明显促进外殖体的初期生长。外殖体建立阶段以1mg·1~(-1)BAP+0.1mg·1~(-1)IBA+0.1mg·1~(-1)GA_3的处理为宜。BAP与IBA明显影响茎的增殖。茎数量随BAP浓度(1—4mg·1~(-1))的增加而增加,但茎长度明显下降。在BAP存在条件下,增加0.1mg·1~(-1)IBA对茎数量没有明显影响,但显著促进茎增长。高浓度的BAP(4rug·1~(-1))明显导致玻璃苗产生,增施0.1mg·1~(-1)IBA在一定程度上可抑制玻璃苗形成。茎增殖阶段BAP浓度明显影响试管苗生根,其生根率、平均根数与限长度随BAP浓度的增加(1—4rug·1~(-1))而降低。2mg·1~(-1)BAP+0.1mg·1~(-1)IBA为茎增殖阶段的最适浓度。生根阶段2mg·1~(-1)IBA显著提高生根率、根数与根长度,同时也有利于试管苗移栽,促进试管苗初期生长。     

鹤顶兰组培快繁技术研究

在鹤顶兰组培快繁过程中,细胞分裂素BA对假鳞茎诱导有极显著影响,KT和ZT的作用不明显;BA和生长素NAA均对假鳞茎的诱导和增强起明显的促进作用,且BA对鹤顶兰幼苗的增殖效果更为显著;GA和番茄汁的合理组配是鹤顶兰生根壮苗的关键。     

中华蜜蜂GnRH相关受体的基因克隆及表达研究

[目的]克隆中华蜜蜂(Apis cerana cerana)促性腺激素释放激素(gonadotrophin releasing hormone,GnRH)相关受体基因,对其进行表达研究。[方法]利用RT-PCR技术克隆了中华蜜蜂的GnRH相关受体基因的cDNA序列,并对其进行生物信息学分析和表达产物的原位杂交组织化学研究。[结果]序列分析显示,GnRH相关受体的cDNA序列全长1 177 bp,开放阅读框长1 050 bp,编码349个氨基酸残基。推导的氨基酸序列具有7个跨膜区;预测的分子量和等电点分别为40.6 kD和9.54。聚类分析显示该蛋白质与其他已知昆虫的GnRHRⅡ具有较近的亲缘关系。原位杂交显示GnRH相关受体基因在中华蜜蜂的脑、精巢、脂肪体以及肠道等组织均有表达。[结论]该研究结果表明GnRH相关受体为昆虫提供了生殖和新陈代谢之间的分子纽带,其在协调昆虫的生殖活动和环境状况的关系中执行了一定的功能。     

来源和质量不同对山羊卵母细胞体外成熟率的影响

比较了卵母细胞级别对体外成熟率的影响,以及促卵泡素(FSH)处理山羊对卵母细胞采集的数量和质量的影响。结果表明:卵母细胞级别对体外成熟率有显著影响,不论是来源于FSH处理卵巢还是屠宰场卵巢,均是A、B级卵母细胞的成熟率高于C级卵母细胞,差异极显著(P<0.01)。但是A、B级卵母细胞之间差异不显著;卵巢来源对卵母细胞采集的数量和质量有显著影响,A、B级卵母细胞在获卵总数中所占的比例,平均每个卵巢获卵母细胞数及A、B级卵母细胞数,均是FSH处理卵巢高于屠宰场卵巢,差异显著(P<0.05);卵巢来源对卵母细胞体外成熟率有显著影响,来自于FSH处理卵巢的卵母细胞体外成熟率高于屠宰场卵巢(81.6%比67.6%),差异极显著(P<0.01)。     

鄂西北产猫眼草提取物体外抗氧化性及光稳定性测试

猫眼草为鄂西北地区常见的野生有毒植物种,经测定具有较强的杀虫、抑菌活性。为了深入开发此植物资源,室内测定其提取物的体外抗氧化性及光稳定性。采用α-脱氧核糖法、邻苯三酚自氧化法、DPPH自由基清除法和铁氰化钾还原法等方法体外评价猫眼草提取物的抗氧化性。同时,采用高效液相色谱法测定其光稳定性。结果表明:①随着猫眼草提取物质量浓度的升高,羟自由基、氧自由基、DPPH自由基的清除率上升,分别高达82.04%、87.99%、87.73%。在一定范围内,随着猫眼草提取物质量浓度的升高,对铁氰化钾的还原能力也在升高。②猫眼草提取物的光稳定性较差,Tween-20(表面活性剂)和水杨酸苯酯(光稳定剂)对其具有一定的光稳定增效作用。     

菱角壳粗多糖体外清除自由基活性的研究

[目的]研究菱角壳粗多糖体外清除自由基的活性。[方法]采用水提醇沉法从菱角壳中提取粗多糖,并对菱角壳粗多糖在体外清除羟自由基(.OH)、1,1-二苯基苦基苯肼(DPPH.)和超氧阴离子(O2-.)的能力进行了研究。[结果]随着浓度的增加,菱角壳粗多糖对3种自由基的清除能力均呈现增强的趋势,在多糖浓度为2.5 mg/ml时,菱角壳粗多糖对羟自由基、DPPH和超氧阴离子的清除率分别为70.6%、66.2%和48.6%。[结论]菱角壳粗多糖具有较强的清除自由基的能力。     

The in vitro diagnosis of anthelmintic resistance in cyathostomins

Cyathostomins are the primary parasitic pathogens of equids. For over 40 years, these nematodes have been controlled using broad spectrum anthelmintics. Three classes of anthelmintic are currently available for this use but, unfortunately, resistance to each of these has now been recorded in cyathostomin populations. As part of an optimal strategy to control cyathostomin infections in the field, it will be important to identify drug-resistant worms at as early a stage as possible. This objective needs to be supported by methodologies that will allow the accurate comparison of anthelmintic resistance in different nematode populations. At present, the faecal egg count reduction test is considered the most suitable method for initial screening for anthelmintic resistance in equine nematode populations. However, in its current state, this test lacks sensitivity. It is also costly and time-consuming to perform. Laboratory-based techniques, such as the egg hatch assay, larval development assay, larval migration inhibition assay and the larval feeding inhibition assay offer alternative options for assessing anthelmintic resistance in nematode populations. All of these tests have been investigated for their utility in measuring drug resistance in sheep nematode populations and some have proven useful. The egg hatch assay, larval development assay and larval migration inhibition assay have been investigated for use in measuring levels of drug resistance in equine nematode populations. However, at best, the results obtained thus far indicate that these tests require further refinement.     

Overfeeding and underfeeding have detrimental effects on oocyte quality measured by in vitro fertilization and early embryonic development in sheep

To determine effects of maternal diet on in vitro fertilization (IVF) and early embryonic development, ewes (n = 48) were divided into control, overfed (ad libitum feeding), and underfed (60% of control) nutritional planes for 8 wk before oocyte collection. Follicular development was induced by twice-daily injections of FSH on days 13 and 14 of the estrous cycle, and ovaries and blood samples were collected on day 15 of the estrous cycle. During the 8-wk experiment, for control ewes BW and BCS did not change, but for overfed ewes mean (± SEM) BW and BCS increased (11.8 ± 1.1 kg and 2.0 ± 0.1, respectively) and for underfed ewes decreased (14.2 ± 0.9 kg and 0.7 ± 0.1, respectively). The number of follicles was determined; oocytes were collected and subjected to in vitro maturation and fertilization. After IVF, developing embryos were evaluated throughout the 8-d culture period. The proportion of cleaved oocytes after IVF and developing morula and blastocyst were less (P < 0.0001) in overfed and underfed ewes than in control ewes. However, number of visible follicles, total number of oocytes, number of healthy oocytes, and percentage of healthy oocytes were similar for control, overfed, and underfed ewes. Serum insulin concentration was greater (P < 0.05) in overfed ewes than in underfed ewes, estradiol 17-β (E₂) concentration was greater (P < 0.05) in underfed ewes than in overfed ewes, but triiodothyronine (T₃) and thyroxine (T₄) concentrations were similar in all treatment groups. These data show that inadequate feeding has a negative effect on oocyte quality which results in lower oocyte cleavage after IVF and morula and blastocyst formation; overfeeding increased serum insulin and underfeeding increased serum E₂ but not T₃ or T₄. These data emphasize the importance of diet for reproductive and metabolic functions. Furthermore, the mechanisms through which enhanced or decreased energy in diet affect oocyte quality and serum insulin and E₂ concentrations remain to be elucidated.     

笼养孟加拉虎雌雄白昼行为的差异

2005年12月～2006年8月,采用瞬时扫描取样法和全事件取样法,对云南野生动物园内5只孟加拉虎行为进行了初步观察。结果表明,在观察期内,笼养孟加拉虎白昼行为时间分配上两性存在一定差异,即雌性的睡眠和卧息多于雄性的睡眠和卧息;雌性的走动和其它行为少于雄性的走动和其它行为。在活动节律上,两性有极大的相似性,只是雌虎在下午的卧息高峰值比雄虎晚约1h。