The effect of cyclopiazonic acid on the development of pale, soft, and exudative pork from pigs of defined malignant hyperthermia genotype

Malignant hyperthermia (MH) and the mycotoxin cyclopiazonic acid (CPA) are each associated with abnormal calcium homeostasis in skeletal muscle, a key underlying factor in the development of pale, soft, and exudative (PSE) pork. To determine whether the natural presence of CPA in livestock feed ingredients contributes to the varying incidence of PSE in the pork industry, various levels of CPA (.1 to 50 mg/kg of diet) were included in the diets of market weight hogs (n = 52) of defined malignant hyperthermia genotype (NN = normal, Nn = a MH carrier, and nn = MH-positive). Animals with two copies of the MH mutation (nn) displayed improved live animal performance compared with NN and Nn animals (increased feed intake, average daily gain, and feed efficiency) but yielded lower quality loin chops as indicated by lower 45-min pH (P<.01), higher Commission Internationale de l'Eclairage (CIE) L* color coordinate values (P<.05), and higher drip losses (P<.01). The effects of CPA varied. In the first feeding trial, conducted under normal outside temperatures (2 degrees C), CPA had no effect (P> .2) on either live animal performance or meat quality. During the second trial, conducted under extreme outside temperatures (-18 degrees C), CPA-dependent reductions (P<.05) in feed intake, average daily gain, and 45-min pH in nn hogs support the possibility of interactions between malignant hyperthermia and dietary CPA on skeletal muscle calcium homeostasis and the development of PSE pork. These results suggest that this interaction may require stressful environmental conditions or the ingestion of CPA doses much higher than occur under natural conditions.     

北京栽培白蘑菇病害的研究

 1979~1980年进行箱式栽培白蘑菇的试验,并同时调查对比病害发生情况,和采用各种措施的效果。     

Effect of tumor infiltrating lymphocytes on the expression of MHC molecules in canine transmissible venereal tumor cells

Canine transmissible venereal tumor (CTVT) can be allo-transplanted across major histocompatibility complex barriers. The expression of MHC molecules is usually low in the progression (P) stage and then greatly increases during tumor regression (R). We investigated the effects of tumor infiltrating lymphocytes (TIL) on the expression of MHC molecules of CTVT cells. Isolated, viable CTVT cells were inoculated at each of 12 sites (1 x 10(8) CTVT cells per site) on the back of six, mixed-breed dogs. Tumor masses were collected every 2-3 weeks and prepared for histopathologic, immunocytochemistry, flow cytometry and immunoblotting studies. The level of MHC expression on tumor cells from different stages of growth was measured. Initially, expression of MHC I and II molecules in P phase CTVT was low. Twelve weeks post-inoculation (PI), expression increased dramatically and it continued to increase during R phase. Tumor growth slowed after 12 weeks PI and tumors entered R phase around 17 weeks PI. We hypothesize that CTVT evades host immunosurveillance and grows progressively for 12 weeks, when it becomes vulnerable and subject to the host's anti-tumor immune responses. We further demonstrated that R phase, but not P phase, TIL were closely associated with the over-expression of MHC I and II molecules by CTVT cells. The number and proportion of TIL were higher in R phase tumors. Supernatants, from R phase co-cultures (CTVT+TIL) and TIL only, promoted MHC I and II expression on P phase CTVT cells. After culturing alone for 1 month, expression of MHC classes I and II molecules in R phase CTVT cells decreased to the level of P phase CTVT cells. However, the above-mentioned supernatants restored their expression of MHC I and II molecules. In contrast, supernatants from P phase TIL or CTVT cells increased expression slightly or had no effect. Therefore, TIL, not CTVT cells, produce the effective substance (s) to promote the expression of MHC molecules by the tumor cells. Heat treated supernatant was unable to promote the expression of MHC I and II molecules by CTVT cells. In conclusion, TIL isolated from R phase CTVT secreted a heat-sensitive, soluble substance(s) that triggered over-expression of MHC I and II after 12 weeks PI. This caused the tumor to enter R phase and helped stop CTVT growth. Our findings will facilitate the understanding and further investigation of the mechanisms that initiate host immune surveillance against tumors.     

Immunopathogenic behaviors of canine transmissible venereal tumor in dogs following an immunotherapy using dendritic/tumor cell hybrid

Canine transmissible venereal tumor (CTVT) is a naturally occurring tumor that can be transmitted between dogs via live tumor cell inoculation. It is also a spontaneous self-regression tumor and its behavior is closely related to host immune responses. Since CTVT had been widely used for tumor models in canine cancers, whether this self-regression may overtake the immunity elicited from an exogenous tumor vaccine remains unclear and certainly worthwhile to be investigated. In this study, we used DCs/tumor hybrids as a tumor vaccine to evaluate the CTVT model. We prepared mature allogeneic dendritic cells from bone marrow and then assessed their phenotype (CD80, CD83, CD86, CD1a, CD11c, CD40 and MHC II), antigen uptake and presenting abilities. Fused dendritic cell/CTVT hybrids were then used as a vaccine, administered three times at two-week intervals via subcutaneous injection near the bilateral auxiliary and inguinal lymph nodes. In comparison with unvaccinated dogs (spontaneous regressed group), within a period of 2.5 months, the vaccinations substantially inhibited tumor progression (p<0.05) and accelerated the rate of regression by a mechanism involving amplification of the host tumor-specific adaptive immune responses and NK cytotoxicity (p<0.001). Pathologic examination revealed early massive lymphocyte infiltration resulting in final tumor necrosis. In addition, there are not any detectable effects on routine physical, body temperature or blood chemistry examinations. In conclusion, our data furnishes a reference value showing that CTVT is a model of potential use for the study of immunity elicited by vaccines against tumors, and also enable early-phase evaluation of the dendritic cell/tumor vaccine in terms of raising host immunity.     

影响根系分解因素(N、C/N、温度和水分)的研究

采用埋袋法研究了影响根系分解的内在(N浓度及C/N)和外界(温度和水分)因素。回归分析结果表明,根系分解率与初始N浓度正相关,与C/N负相关;林地内温度和水分条件不同,也影响根系分解率;分解150 d后未伐林地根系分解最快。     

Recombinant equine growth hormone administration: effects on synovial fluid biomarkers and cartilage metabolism in horses

REASONS FOR PERFORMING STUDY: Recombinant equine growth hormone (reGH) has recently been evaluated for effects on body condition and wound healing. It has the potential to influence articular cartilage via stimulation of IGF-1. OBJECTIVES: To investigate effects of administration on synovial joint metabolism. METHODS: Six mature horses were given 20 microg/kg bwt reGH daily for 8 weeks by i.m. injection. Three control horses were injected with sterile water. Serum and synovial fluid samples were collected at 6, 8, 11 and 16 weeks for GH and IGF-1 assays. Articular cartilage harvested at week 16 was evaluated by Western analysis using monoclonal antibodies BC-13, BC-4, 8-A-4 and CH-3. RESULTS: Concentrations of IGF-1 in serum and synovial fluid were significantly elevated (P < 0.05) at 6 and 8 weeks in the reGH group. Glycosaminoglycan concentrations in synovial fluid were significantly less than controls at these time points, suggesting that reGH may modulate proteoglycan metabolism in articular cartilage. In the reGH group, there were not any alterations in synovial fluid content of 3B3(-) epitope or aggrecan metabolite, or in aggrecan or link protein catabolites retained within cartilage, that might be expected with development of osteoarthritis. CONCLUSIONS: Intramuscular administration of reGH may be a more efficient means of delivery of IGF-1 to joints for cartilage resurfacing initiatives. POTENTIAL RELEVANCE: We found no alterations in cartilage metabolism indicative of development of osteoarthritis.     

Hookworm dermatitis due to Uncinaria stenocephala in a dog from Saskatchewan

Uncinaria stenocephala hookworm dermatitis (uncinariosis) was diagnosed on fecal examination and macerated skin biopsy in a 1.5-year-old greyhound dog from Saskatchewan. This is the first reported case in Canada. Treatment with moxidectin cleared gastrointestinal and dermal infections.     

松墨天牛肠道BS16基因组及其纤维素酶活特性分析

蜡状芽孢杆菌BS16是从松墨天牛肠道筛选获得的1株具有纤维素酶活性的细菌,为了解BS16的菌株基因组特性及其纤维素降解功能,采用扫描电镜、基因组学分析、DNS法探究BS16的形态特征、纤维素酶解基因、纤维素酶活。结果表明：BS16的细胞为胶囊状,长为3～4 µm,直径为0.5～1.2 µm;蜡状芽孢杆菌BS16基因组全长5 347 914 bp,包含5 494个基因,其中包括5 338个蛋白质编码基因、11个rRNA基因、102个tRNA基因和17个sRNA基因;BS16基因组中主要由GH4、GH5、GH8、GH13家族编码纤维素酶;蜡状芽孢杆菌BS16具有完整的纤维素酶系,在其分泌的纤维素酶中内切葡聚糖酶活性最高为（2.186 ± 0.081）U/mL,其内切葡聚糖酶的酶活性最适pH值为5.0、最适温度为40 ℃。     

On farm observations to increase genetic gain in breeding schemes for village poultry production – A simulation study

To improve genetic gain of breeding programs for village poultry production, breeding schemes with observations obtained in village production systems using individual (VIO) and group recording (VGO) were examined under different levels of genotype-by-environment-interactions (GxE). GxE was modeled by varying the correlation between traits measured in the breeding station and village environments for bodyweight (r_{g_BW}) and egg production (r_{g_EP}). Relative and absolute genetic gains obtained from VIO and VGO were used for comparison between the schemes. Results showed that village observations significantly improved genetic gains compared to the scheme without birds tested in the village. The improvement was only slightly larger with individual observations than with group observations. Higher r_{g_BW} and r_{g_EP} led to lower relative genetic gain, but a higher absolute gain of VIO and VGO. It is recommended to apply a breeding scheme using group recording of village performance when strong GxE in breeding for village poultry is expected.     

常见动物乳与人乳的营养成分比较分析

乳中富含多种人体所必需的营养成分,对机体的生长发育及免疫功能具有重要作用。除牛乳外,水牛乳、马乳、骆驼乳、山羊乳、驴乳、牦牛乳等特色乳也逐渐进入人们的视野。同时人乳是婴儿最天然的理想食品,是婴儿早期主要的营养物质来源,含有丰富的营养物质及生物活性成分。为了更好的比较7种常见动物乳及人乳的差异性和优势性,本文总结了其在乳糖、乳脂、乳蛋白、矿物质、维生素等营养物质成分方面的差异,发现牦牛乳的蛋白质含量最高,氨基酸种类丰富;马乳的乳糖含量最高;而骆驼乳的乳脂肪含量则较高,水溶性维生素含量也最高;驴乳相比于其他几种常见乳,则具有低脂高糖等特点。