肌肉生长抑制素的研究进展及应用现状

肌肉生长抑制素基因是限制肌肉超常发育的负调控基因,缺失或突变会导致双肌现象的产生。本文重点探讨了肌肉生长抑制素的分子作用机理,论述了该基因的发现、遗传效应、同源性、组织特异性、定位和结构等方面的研究现状及临床应用。     

肌肉生长抑制素研究进展

肌肉生长抑制素是一种分泌型的多肽。小鼠中该基因的缺失可导致骨骼肌的明显增大,而且在双肌牛中该基因的缺失产生了突变,这表明肌肉生长抑制素可能是骨骼肌生长的负调控因子。本文综述了肌肉生长抑制素的基因结构及其分子作用机制,并就它对动物体成分的影响、应用及尚存在的问题作了概述。     

肌肉生长抑制素(MSTN)对肌肉调控的分子作用机制

肌肉生长抑制素(Myostatin,MSTN)是肌肉生长的负调控因子,抑制成肌细胞的增殖和分化.MSTN作为胞外信号分子可与成肌细胞膜上的受体结合引起受体自身的磷酸化,启动细胞内一系列信号传导过程,作用于生肌决定因子(MyoD)靶基因的调控区,调节肌肉组成蛋白和蛋白基因的表达.     

猪完整的生长抑制素基因的特性及在不同猪种中的表达

生长抑制素(MSTN)是生长因子β超家族成员,是肌肉生长发育的重要影响因子,是肌肉生长的负调控因子,并与所谓的牛的双肌表型有关。比利时的皮特兰猪是双肌表型的代表猪种,与双肌牛有着共同的肌肉表型,表明生长抑制素基因可能是猪肌肉过度增长的候选基因。本研究对5个品种45头猪的生长抑制素基因的完整序列进行了测定和分析,包括具有特别发达肌肉的皮特兰猪和肌肉欠发达的梅山猪和野猪。经测序,得到了7626 bp的猪生长抑制素基因,包括5′和3′非翻译序列,并且发现了15个多态位点,其中3个位于启动子区,5个位于内含子1内,7个位于内含子2内。大部分的突变位点是在对本试验获得的MSTN基因序列和已发表的猪生长抑制素基因进行比对时发现的。然而,定位于猪生长抑制素基因启动子区447位点处的突变位点在皮特兰猪中有很高的等位基因频率,而不是公认的肌细胞增强因子3结合位点。Sybr Green实时定量PCR检测结果显示,这个突变位点在4周龄猪的背最长肌中表达。     

品种和体重对猪肌肉生长抑制素表达的影响

本文旨在研究猪的体重和品种对其背最长肌的肌肉生长抑制素基因表达的影响,并对猪100kg时的胴体性状与肌肉肌肉生长抑制素基因表达量的相关性进行分析。试验采用荧光定量PCR方法,以β-actin基因为内标,研究不同体重(20、50和100kg)和品种(汉普夏猪和长白×撒坝猪)对猪背最长肌的肌肉生长抑制素基因表达的影响,同时考察试验猪在100kg时的胴体肉质指标。结果表明:①猪背最长肌中肌肉生长抑制素的表达随体重的增加呈上升的趋势(P>0.05);②相同体重条件下长撒猪背最长肌中肌肉生长抑制素表达均显著高于汉普夏猪(P<0.05),其中20kg时达到极显著水平(P<0.01);③肌肉生长抑制素的表达与瘦肉率呈极显著的负相关(P<0.01),与背膘厚则呈极显著的正相关(P<0.01),与滴水损失和肌内脂肪的相关性不显著(P>0.05)。本研究结果表明猪背最长肌的肌肉生长抑制素基因的表达量随体重增加而提高,品种间差异显著,并且肌肉生长抑制素基因的表达与瘦肉率、背膘厚存在显著的相关性。     

肌抑素基因的结构、功能及应用

肌抑素(myostatin)属于TGF-β超家族成员,是动物骨骼肌生长的主要负调控因子。对肌抑素基因及其功能的研究,有助于提高畜禽的产肉性能和肉品质,也有利于治疗人类肌萎缩症等肌肉疾病。另外,肌抑素还具有降低脂肪含量,修复骨组织等功能。本文对肌抑素基因的结构、功能及应用进行了简要概述。     

双肌性状形成的分子机理及其研究进展

肌肉生成是一个复杂的正负调控过程,双肌品种以其特有的饲料报酬高、瘦肉率高’、生长快在近几年来逐步受到育种专家的重视。研究表明,肌肉生长抑制素(mysatatin,MSTN)缺失或突变会导致肌肉过度生长或肥大,即双肌现象;双肌性状受常染色体上一对等位基因控制,存在主基因效应。现从肌肉生长机理入手,分别从不同家畜双肌现象阐明该性状的分子机理及其应用前景。     

肌肉生长抑制素对动物肌肉、脂肪和骨骼的影响

肌肉生长抑制素是转化生长因子 β超家族成员之一,具有众多的生理功能。近来的研究表明,肌肉生长抑制素除对肌肉生长有负调控作用外,还对脂肪的沉积和骨骼的生长发育具有调节作用,甚至还能影响肌腱和韧带的强硬度。本文主要从肌肉生长抑制素的结构、基因表达及其对动物肌肉、脂肪和骨骼的作用等方面进行综述。     

抑制素、活化素和卵泡抑素研究进展

抑制素、卵泡抑素和活化素是3种参与垂体促卵泡素调控过程的糖蛋白激素,随着对促卵泡素调控过程的深入了解,发现这3种蛋白在动物生殖周期中发挥着重要的作用。文章主要就抑制素、卵泡抑素和活化素的结构特征、生理功能以及抑制素和卵泡抑素对活化素生物学活性的抑制机理进行了综述。     

牛双肌基因PCR-SSCP分析

双肌(肌肉生长抑制素)基因是一种肌肉生长的负调控因子,试验应用PCR-SSCP和测序的方法对我国秦川牛、南阳牛双肌基因的第3外显子进行了多态性分析.结果表明:第3外显子938位G→A的单核苷酸突变造成了南阳牛第3外显子扩增片段呈多态性;秦川牛中未发现突变.     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

Smart Phone Assisted City-scale Wireless Sensor Network Deployment for Transportation System Monitoring

<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.