醉马草内生真菌共生体对其伴生植物种子萌发的影响

以我国西北部天然草原广泛分布的烈性毒草醉马草(Achnatherum inebrians)和其主要伴生种针茅(Stipa capillata)、硬质早熟禾(Poa sphondylodes)为供试材料,采用纸上发芽法(TP)测定醉马草地上部分的水浸提液对2种植物种子萌发和幼苗生长的影响。结果表明:带菌(E+)醉马草的水浸提液对受体植物的种子萌发和幼苗生长主要表现抑制作用(P0.05),而且抑制作用随浸提液浓度升高而加强;不带菌(E-)醉马草的水浸提液对受体植物的种子萌发没有显著的影响,只有0.2 g/mL的水浸提液对幼苗的生长有显著的抑制作用。综上所述,带菌醉马草提取液对针茅和硬质早熟禾种子萌发和幼苗生长有强烈的抑制作用,而不带菌醉马草则对2种禾草没有显著的影响。     

鄱阳湖钉螺体内吸虫尾蚴记述

作者从1999-2000年共解剖鄱阳湖草洲钉螺87146只，先后发现裸头类、矛口类、单盘类、微尾类、叉尾类、对盘类、无尾类尾蚴共15种，本文将各种尾蚴的形态特征予以简介。     

MDCC—MSB1培养基上清液中DNA活性的定性研究

将 Ｍ Ｄ Ｃ Ｃ Ｍ Ｓ Ｂ１ ４８ 小时培养物 １０００ｒ／ｍ ｉｎ 离心的上清液分别用 Ｒ Ｎ Ａ 酶、 Ｄ Ｎ Ａ 酶和蛋白酶 Ｋ 处理后,进行体外试验。结果表明,只有 Ｄ Ｎ Ａ 酶处理后的上清液失去了体外抑制 Ｍ Ｄ Ｖ“８１４”增殖的作用。将该上清液 １００００ｒ／ｍ ｉｎ 离心所得的沉淀分别用上述酶处理后进行体内试验。结果表明,只有 Ｄ Ｎ Ａ 酶处理的样品失去了体内促进 Ｍ Ｄ Ｖ 京１ 株致瘤的作用。同时,电泳分析结果证明,该上清液中确实存在 Ｄ Ｎ Ａ。     

Kinetic evaluation of normal walking and jumping in cats, using a pressure-sensitive walkway

The kinetic parameters of the limbs of 23 normal, client-owned cats were evaluated by encouraging them to walk and jump normally on a pressure-sensitive walkway. Each cat was encouraged to walk across the walkway five times over a period of 30 to 45 minutes (by using food, toys, the owner's presence and a purpose-built tunnel) at a target speed of 0.6 m/s (and an acceleration of less than +/- 0.1 m/s(2)). They were then encouraged to jump on to the walkway from a height of 1 m five times at five-minute intervals. The kinetic parameters of peak vertical force (PVF) and vertical impulse (VI) were measured for each limb (the forelimbs only for the jumps), and expressed as a percentage of bodyweight (PVF(%BW) and VI(%BW/S)). Fifteen of the 23 cats satisfactorily completed three to five walks and two to five jumps that could be analysed. There were no significant differences between the PVF or VI of the left and right limbs, but both parameters were significantly greater for the forelimbs than the hindlimbs (P<0.001) for the walking data. The mean (sd) PVF(%BW) for the forelimbs and hindlimbs were 48.2 (6.0) and 38.3 (4.0), respectively, and the mean VI(%BW/s) were 16.9 (3.2) and 13.3 (2.8). Jumping down generated significantly greater PVF (P<0.01) and slightly greater VI than during walking; there were no significant differences between the left and right forelimbs. The mean PVF(%BW) was 148.9 (16.4) and the mean VI(%BW/s) was 18.1 (4.3).     

鸭DCN基因编码区扩增、序列分析及其在大肠杆菌中的表达、蛋白纯化

采用RT-PCR方法从鸭腿肌总RNA中扩增了鸭核心蛋白聚糖基因编码区序列,进行序列分析,并将编码鸭核心蛋白聚糖成熟蛋白的核酸片段连入原核表达载体pET-32a(+)中,加入IPTG诱导其表达后,亲和层析纯化表达的蛋白。采用SDS-PAGE检测,用质谱方法对表达的蛋白进行鉴定。研究成功克隆出鸭核心蛋白聚糖基因编码区序列,序列分析表明,鸭DCN编码区序列由1074个碱基组成,编码357个氨基酸,其中信号肽有16个氨基酸。将鸭DCN蛋白划分为9个结构域(LRR1-9),结合人DCN序列进行序列分析推测结构域中LRR4、5与TGF-β可能存在一定关系。SDS-PAGE检测和质谱鉴定结果表明获得了分子量为54.7ku的鸭DCN融合蛋白。     

Detection of specific antibody responses to vaccination in variable flying foxes (Pteropus hypomelanus)

Megachiropteran bats are biologically important both as endangered species and reservoirs for emerging human pathogens. Reliable detection of antibodies to specific pathogens in bats is thus epidemiologically critical. Eight variable flying foxes (Pteropus hypomelanus) were immunized with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA). Each bat received monthly inoculations for 2 months. Affinity-purified IgG was used for production of polyclonal and monoclonal anti-variable flying fox IgG antibodies. ELISA and western blot analysis were used to monitor immune responses and for assessment of polyclonal and monoclonal antibody species cross-reactivity. Protein G, polyclonal antibodies, and monoclonal antibodies detected specific anti-DNP antibody responses in immunized variable flying foxes, with protein G being the most sensitive, followed by monoclonal antibodies and then polyclonal antibodies. While the polyclonal antibody was found to cross-react well against IgG of all bat species tested, some non-specific background was observed. The monoclonal antibody was found to cross-react well against IgG of six other species in the genus Pteropus and to cross-react less strongly against IgG from Eidolon helvum or Phyllostomus hastatus. Protein G distinguished best between vaccinated and unvaccinated bats, and these results validate the use of protein G for detection of bat IgG. Monoclonal antibodies developed in this study recognized immunoglobulins from other members of the genus Pteropus well, and may be useful in applications where specific detection of Pteropus IgG is needed.     

猪传染性胃肠炎病毒分子生物学研究进展

猪传染性胃肠炎病毒(TGEV)基因组为不分段的单股正链RNA,其编码4种结构蛋白和3种非结构蛋白。TGEV S蛋白是基因工程研究的重点,近年来,S蛋白在大肠埃希菌、沙门菌、腺病毒等中得到了高效表达。将传染性胃肠炎病毒的基因组人工改造成为感染性cDNA的表达载体,此载体可在ORF3处插入外源基因,异源基因绿荧光蛋白可稳定、高效地表达。TGEV基因1和其他冠状病毒相比保守性很强,所以对TGEV聚合酶的研究,特别是其中保守酶的研究,对于抗TGEV及其他冠状病毒药物的研究有着重要的意义。     

Cartilage proteoglycans from normal and osteochondrotic porcine joints.

Modern pigs grow fast but are highly susceptible to degenerative joint abnormalities, including osteochondrosis. Normal and osteochondrotic humeri and femurs were obtained from five normal and ten lame adolescent boars to study cartilage proteoglycans. Histological examination of joints indicated a locally-reduced intensity of proteoglycan staining by safranin-O in lesion areas of cartilage. Cartilage proteoglycans extracted with 4.0 M guanidinium chloride were studied using Sepharose 2B gel chromatography. The proteoglycans from severely osteochondrotic joints were less (P less than 0.05) aggregated and contained a greater (P less than 0.05) proportion of smaller monomers than those from normal joints. Loss or damage of core protein, including its hyaluronic acid-binding regions, may account for the greater proportion of small monomers. The results also indicated that the proportion of hyaluronic acid in the total glycosaminoglycan uronic acid fraction, estimated by Sephadex G-200 chromatography and cellulose acetate electrophoresis, was lower (P less than 0.05) for the extracted proteoglycans than for the residual or the whole cartilage proteoglycans in all joints studied.     

Effect of cortisol on luteinizing hormone release during sexual behavior in the boar.

The effect of inhibiting the rise in cortisol concentrations that occurs at copulation upon luteinizing hormone release was studied in seven adult boars. Plasma samples were collected for assay of luteinizing hormone, testosterone and cortisol on a control day and before, during and after exposure to an estrous sow. The area under the curve was used to evaluate hormone production and treatment effects were evaluated by a paired Student's t-test. The 11 beta-hydroxylase inhibitor, metyrapone, was used to suppress glucocorticoid hormone production. Cortisol concentrations increased significantly (p less than 0.05) after breeding compared to values on the control day while treatment with metyrapone prior to breeding prevented the cortisol increase (p greater than 0.05). Although luteinizing hormone production increased significantly after copulation in both breeding experiments, metyrapone pretreatment resulted in a reduction of luteinizing hormone secretion (p less than 0.05). Testosterone production was also reduced in boars pretreated with metyrapone. The results suggest that the increased levels of cortisol occurring at copulation may enhance luteinizing hormone release in boars.     

Dietary supplementation with Acanthopanax senticosus extract enhances gut health in weanling piglets

The present study was conducted to investigate the effects of Acanthopanax senticosus extract (ASE) as a dietary additive on gut health in weanling piglets by examining diarrhea frequency, intestinal microbiota and morphology. A total of 96 Duroc× (Landrace × Yorkshire) piglets weaned at 21 days of age with an average initial body weight (BW) of 5.6 ± 0.4 kg were randomly assigned to 3 treatment groups with 4 duplicates of 8 piglets each. The piglets were fed basal diet to which had been added 0 or 1 g/kg of ASE, or 0.7 g/kg antibiotics, respectively. Fecal consistence was monitored twice daily and the frequency of diarrhea was calculated. On day 21 after the initiation of supplementation, 8 piglets were randomly selected from each treatment group (2 piglets per pen) and slaughtered. The jejunum, ileum, colon and cecum were then excised and fixed in 10% neutral formalin solution to determine villus height and crypt depth, after their contents were collected to determine microbiota. The results showed that dietary supplementation with ASE increased (P < 0.05) the density of bacterial populations that co-migrated with Lactobacillus amylovorus, Lactobacillus salivarius, Bacillus subtilis, and Clostridium lituseburens, but decreased (P < 0.05) those co-migrating with Staphylococcus aureus, Salmonella typhimurium, Ruminococcus forques, and E. coli O157:H7 in the PCR-DGGE profiling analysis when compared with the control group. The villus height of the duodenum, jejunum and ileum increased (P < 0.05) by 14.8, 13.7 and 10.0%, while the crypt depth decreased (P < 0.05) by 17.9, 9.1 and 12.1%, respectively, in response to dietary ASE supplementation. Additionally dietary supplementation with ASE or an antibiotic decreased (P < 0.05) the frequency of diarrhea by 55.6 and 52.2%, respectively, compared with the control group. In conclusion, these findings suggest that dietary supplementation with ASE could regulate the microbiota composition and maintain a normal morphology of gut mucosa in weanling piglets, thereby decreasing diarrhea that resulted from weaning stress.