绵羊CCNG1基因克隆及表达分析

细胞周期蛋白cyclin G1(CCNG1)是一个重要的细胞周期调控因子,参与哺乳动物颗粒细胞增殖、卵母细胞成熟等繁殖生物学过程,但其在绵羊中鲜有报道。为了研究CCNG1基因对绵羊发情调控以及季节性繁殖的影响,文章对绵羊CCNG1基因进行了克隆和组织表达谱分析,利用Real-time PCR对该基因在多浪羊(常年发情)与中国美利奴羊(季节性繁殖)发情周期不同阶段性腺轴组织的表达变化进行了实时检测。获得了绵羊CCNG1基因部分cDNA序列,其中编码区全长885 bp,编码294个氨基酸。CCNG1蛋白结构经预测存在多个磷酸化位点和蛋白激酶C磷酸化位点。CCNG1基因在所检测绵羊各组织中均有表达,但在卵巢与肾脏中为高丰度表达;CCNG1在不同绵羊品种发情周期不同阶段性腺轴组织的表达变化规律基本一致,卵巢、子宫、松果体、垂体均是在发情期达到峰值。但是在发情期和发情后期卵巢CCNG1的表达量存在显著的品种间差异(P<0.01)。研究结果表明,CCNG1可能通过参与卵泡的生长发育继而达到对绵羊发情和季节性繁殖的调控。     

Genetic diversity in nine native Turkish sheep breeds based on microsatellite analysis

The genetic variability of 204 sheep from nine breeds (Awassi, Çine Çapar?, Karaka?, Karya, Karayaka, Morkaraman, Norduz, Sak?z and Tuj) growing in four different regions (western, northern, eastern and south‐eastern Anatolia) was assessed using 18 microsatellite loci. High mean number of alleles, allelic richness and factorial correspondence analysis showed the degree of admixture between native sheep breeds of Turkey. The Karya and Çine Çapar? breeds were observed as the most distinct of the breeds, and possible introgressions were detected in other breeds. It was found that 8.9% of genetic variation resulted from the difference between the populations. The genetic variation in Turkish breeds was not much higher than that of European breeds, which might be a consequence of the recent sharp decrease in sheep numbers.     

Biological and Statistical Errors Make Inferences Circumspect: Response to Bender and Weisenberger

ABSTRACT Bender and Weisenberger (2005) reported that desert bighorn sheep (Ovis canadensis) on San Andres National Wildlife Refuge (SANWR), New Mexico, USA, were primarily limited by rainfall. However, they failed to mention, or were unaware, that persistent long-term predator control was used to enhance population growth at SANWR. Additionally, lamb:female ratios were collected throughout the year, rather than dates typically associated with assessing recruitment, and therefore influence of precipitation on lamb recruitment was unknown. Finally, model predictions forwarded by Bender and Weisenberger (2005), that carrying capacity of SANWR is zero when annual rainfall is <28.2 cm, were not supported by data, nor were their model results properly interpreted. The coefficient of determination value of 88.9% for the relationship between population size and current year's precipitation was primarily a function of serial correlation between successive years in population data, with current year's precipitation accounting for only 3.8% of this value. This suggests that precipitation was a weak predictor of population increase. These errors in concert make biological inferences reported in Bender and Weisenberger (2005) of limited value.     

Estimates of heritability and genetic correlations for milk coagulation properties and individual laboratory cheese yield in Sarda ewes

Objective of this study was to estimate genetic parameters of milk coagulation properties (MCPs) and individual laboratory cheese yield (ILCY) in a sample of 1018 Sarda breed ewes farmed in 47 flocks. Rennet coagulation time (RCT), curd-firming time (k₂₀) and curd firmness (a₃₀) were measured using Formagraph instrument, whereas ILCY were determined by a micromanufacturing protocol. About 10% of the milk samples did not coagulate within 30 min and 13% had zero value for k₂₀. The average ILCY was 36%. (Co)variance components of considered traits were estimated by fitting both single- and multiple-trait animal models. Flock-test date explained from 13% to 28% of the phenotypic variance for MCPs and 26% for ILCY, respectively. The largest value of heritability was estimated for RCT (0.23±0.10), whereas it was about 0.15 for the other traits. Negative genetic correlations between RCT and a₃₀ (−0.80±0.12), a₃₀ and k₂₀ (−0.91±0.09), and a₃₀ and ILCY (−0.67±0.08) were observed. Interesting genetic correlations between MCPs and milk composition (r_G>0.40) were estimated for pH, NaCl and casein. Results of the present study suggest to use only one out of three MCPs to measure milk renneting ability, due to high genetic correlations among them. Moreover, negative correlations between ILCY and MCPs suggest that great care should be taken when using these methods to estimate cheese yield from small milk samples.     

Effects of Glycosylation of the Residue at Position 14 in Ovine Angiotensinogen on the Human Renin Reaction

A mutant angiotensinogen, S14N, in which Ser¹⁴ of ovine angiotensinogen was replaced by Asn to form a N-glycosylation site, was produced in CHO cells. The molecular weight was about 3,000 larger than that of wild-type ovine angiotensinogen, indicating that S14N angiotensinogen was glycosylated at Asn¹⁴. In the reaction with human renin, the K _m of mutant angiotensinogen was 3 times increased, but the V _max was not affected by the mutation.     

The molecular size of nematode acetylcholinesterases and their separation from nematode allergens

The molecular size of nematode acetylcholinesterases, and their separation from nematode allergens. International Journal for Parasitology 3: 735–741. Acetylcholinesterases and allergens were derived from two parasitic nematodes, Nippostrongylus brasiliensis which parasitises rats and Trichostrongylus colubriformis which infects sheep and guinea pigs.

Chromatographic studies indicated that the mol. wt of nematode acetylcholinesterases lies between 65,000 and 75,000. The acetylcholinesterases of both species were separated from nematode allergens whose mol. wt is in the range of 10,000–50,000.

γG binding antigens of T. colubriformis were located in fractions with a mol. wt range of 30,000–150,000. γE binding activity was confined to allergenic material with a mol. wt of less than 70,000.     

Prevalence of Cystic Echinococcosis in Slaughtered Sheep as an Indicator to Assess Control Progress in Emin County,Xinjiang, China

Hydatid disease imposing serious threat on human health and great loss in live¬stock pastoralism remains a major public health problem in western China. To assess and monitor the effect of control program on transmission dynamics, we used the prevalence of cystic echinococcosis in slaughtered sheep at slaughterhouse as an indicator during the period of 2007 to 2013 in Emin County, Xinjiang Uygur Autonomous Region, China. The results showed a significant decline trend of prevalence in all age groups during the 7 years when the control program was implemented; particularly, the rate was reduced by 72% after first 3 years. Among the sheep slaughtered, the age distribution evidenced that the prevalence increased significantly as the sheep grew older. The baseline data indicated that the rate was 4.5% at the age <1, 6.7% at age 2~, and reached to the highest 17.9% at age ≥4 years. Earlier response to the intervention pressure was seen in the sheep at the younger age. Significant decline started from 2008 at the age <1, from 2009 at age of 1~, 2010 at 2~ to 3~, and the latest, in 2012 at age ≥4. This study demonstrated that the prevalence of cystic echinococcosis in slaughtered sheep may be used as an indicator to assess and monitor the transmission status during and after control program providing information for betterment of performance to sustain control strength.     

Analysis of Polycerate Mutants Reveals the Evolutionary Co-option of HOXD1 for Horn Patterning in Bovidae

In the course of evolution, pecorans (i.e., higher ruminants) developed a remarkable diversity of osseous cranial appendages, collectively referred to as “headgear,” which likely share the same origin and genetic basis. However, the nature and function of the genetic determinants underlying their number and position remain elusive. Jacob and other rare populations of sheep and goats are characterized by polyceraty, the presence of more than two horns. Here, we characterize distinct POLYCERATE alleles in each species, both associated with defective HOXD1 function. We show that haploinsufficiency at this locus results in the splitting of horn bud primordia, likely following the abnormal extension of an initial morphogenetic field. These results highlight the key role played by this gene in headgear patterning and illustrate the evolutionary co-option of a gene involved in the early development of bilateria to properly fix the position and number of these distinctive organs of Bovidae.