microRNA-let-7家族在约克夏猪甲状腺生长发育过程中的表达分析

miR-let-7广泛参与动物组织器官发育调控,是研究猪甲状腺发育的重要候选miRNAs。为了研究miR-let-7家族在约克夏猪(Sus scrofa)甲状腺生长发育过程中的作用,本实验一方面通过对不同发育阶段(胚龄105,出生后60、90、150日龄)的猪甲状腺组织切片进行苏木精-伊红染色(hematoxylin-eosin staining,HE),研究甲状腺发育形态学的变化;另一方面,采用原位杂交(in situ hybridization,ISH)和荧光定量PCR技术鉴定miR-let-7家族在不同生长阶段(胚龄105,出生后60、90、150日龄)约克夏猪甲状腺中的表达。HE染色结果发现,甲状腺滤泡随着日龄的增加逐渐增大。原位杂交结果显示,miR-let-7主要位于甲状腺的滤泡上皮细胞中,并且let-7的表达在出生后有先减少后增加的态势。通过荧光定量PCR结果发现,在生长期随着日龄的增加,let-7d-5p、let-7f和let-7g的相对表达量逐渐上升,let-7c、let-7d-3p、let-7e和let-7i的表达先升后降。研究结果提示,约克夏猪甲状腺miR-let-7的表达直接或间接影响甲状腺激素水平的变化,在甲状腺生长发育中发挥了重要的作用,为深入研究猪的生长发育提供了一个新的思路。     

邻菲咯啉浓度对瘤胃微生物体外发酵的影响

邻菲咯啉是一种二肽酶抑制剂。本试验用体外法测定了不同浓度邻菲咯啉对瘤胃微生物发酵产气量、氨氮浓度、真蛋白含量及饲料干物质降解率的影响。结果表明 ,邻菲咯啉浓度与产气量呈直线负相关(Y=-16.75X +29.52 ,r=0.7976,P<0.05);与发酵液氨氮浓度呈直线负相关(Y= -0.5757X +3.3036,r=0.8384,P<0.05) ;与发酵管内容物真蛋白含量呈直线正相关(Y=1.35X +11.45,r=0.8423,P<0.05) ;与内容物饲料干物质降解率呈直线负相关(Y= -10.14X +55.08,r=0.9275,P<0.01)。     

温光条件对离体大蒜鳞茎形成和内源激素变化的效应

以徐州白蒜和太仓白蒜２个地方品种试管苗进行试管鳞茎培养，结果表明，鳞茎形成需较高温度条件的诱导，１５℃下培养的试管苗转入２０～２５℃高温下可形成鳞茎；４℃低温预处理促进鳞茎形成。对长日照的要求因品种而异，早熟品种徐州白蒜在８～１６ｈ日长下均可形成鳞茎，晚熟品种太仓白蒜在８ｈ短日下不形成鳞茎。鳞茎形成过程中，内源激素ＡＢＡ含量升高，ｉＰＡ下降，ＩＡＡ先剧烈升高，然后下降，ＧＡ先下降，然后升高。鳞茎开始形成时，ｉＰＡ／ＡＢＡ和ＧＡ／ＡＢＡ下降，ＩＡＡ／ＡＢＡ升高。温度对ＩＡＡ／ＡＢＡ有明显影响，对长日照要求严格的品种其ｉＰＡ／ＡＢＡ变化受光周期的调节。     

减蛋综合征病毒AA-2株适应体外培养的研究

在分离并系统鉴定了减蛋综合症病毒AA-2株的基础上，进行了该毒株的体外培养试验，以寻求适应于细胞培养物中继代的细胞适应毒。结果表明，AA-2毒株可在鸭胚成纤维细胞（DEF）、鸭胚肾细胞（DEK）、鸭胚肝细胞（DEL）、鸡胚成纤维细胞（CEF）、鸡胚肾细胞（CEK）和鸡胚肝细胞（CEL）上增殖和继代，并随着继代次数的增加，CPE潜伏期缩短，持续期延长，半数细胞感染量（TCID50）呈逐代增加趋势，血凝效价（HA）逐代稳步增强，至第15代之后，之些变化趋于稳定。证明用鸭胚细胞培养的AA-2株病毒在PK-15，BHK-21，SP2/0等细胞中增殖的迹象。还较为系统的测定了第19代DEF毒的其它特性。发现在接毒后120小时，HA及TCID50值最高，细胞适应毒对鸭胚致死率为10%，比原毒降低23%，理化特性与原毒一致，且仍保持原毒的抗原性。     

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.     

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.