家畜性别控制技术的研究进展

在畜牧生产中,人为控制出生家畜的性别可以降低生产成本,提高经济效益。随着科技的进步和研究的不断深入,家畜性别控制技术也在不断的完善。作者综述了X、Y精子的分离和胚胎性别鉴定这两项家畜性控技术的发展历程和研究现状,并对其今后的研究方向及应用前景进行了展望。     

Vitamin D Status in Different Stages of Disease Severity in Dogs with Chronic Valvular Heart Disease

Background

In humans with heart disease, vitamin D deficiency is associated with disease progression and a poor prognosis. A recent study showed that serum 25‐hydroxyvitamin D [25(OH)D] concentration, the hallmark of vitamin D status, was lower in dogs with heart failure than in normal dogs, and a low concentration was associated with poor outcome in dogs with heart failure.

Objectives

To elucidate the vitamin D status of dogs with chronic valvular heart disease (CVHD) at different stages of disease severity.

Animals

Forty‐three client‐owned dogs with CVHD.

Methods

In this cross‐sectional study, dogs were divided into 3 groups (14 dogs in Stage B1, 17 dogs in Stage B2, and 12 dogs in Stage C/D) according to ACVIM guidelines. Dogs underwent clinical examination including echocardiography. Serum 25(OH)D concentrations were measured in each dog.

Results

Serum 25(OH)D concentration was significantly lower in Stage B2 (median, 33.2 nmol/L; range, 4.9–171.7 nmol/L) and C/D (13.1 nmol/L; 4.9–58.1 nmol/L) than in Stage B1 (52.5 nmol/L; 33.5–178.0 nmol/L) and was not significantly different between Stage B2 and Stage C/D. Among clinical variables, there were significant negative correlations between 25(OH)D concentration and both left atrial‐to‐aortic root ratio and left ventricular end‐diastolic diameter normalized for body weight.

Conclusions and Clinical Importance

These results indicate that vitamin D status is associated with the degree of cardiac remodeling, and the serum 25(OH)D concentration begins to decrease before the onset of heart failure in dogs with CVHD.     

Altered vitamin D metabolic system in follicular cysts of sows

This study aimed to examine 25OHD₃ concentration in the fluid of follicular and follicular lutein cysts of sows in comparison with preovulatory follicles as well as immunolocalize vitamin D metabolic enzymes (CYP27B1 and CYP24A1) and determine their protein abundances in the cyst wall. We have shown for the first time that 25OHD₃ level in the fluid of both cyst types was significantly lower than in preovulatory follicles. Furthermore, we have demonstrated CYP27B1 and CYP24A1 protein immunolocalization and abundance in follicular and follicular lutein cysts. The abundance of protein for both metabolic enzymes was decreased in ovarian cysts when compared to preovulatory follicles. We propose that altered VD metabolism in ovarian cyst might associate with their formation in sows.     

小黑麦与黑麦花序结构和籽粒特性比较

植物的花序结构及其形态特征是影响种子生产性能的重要因素。对于禾本科植物而言,其花序大小、小穗数、小花数及小花的外稃、内稃和芒的性状特征直接影响种子形成和产量。本研究通过测定小黑麦品系C2、C35和黑麦品系C13、C33的花序结构特征,得到以下结果:小黑麦花序[(14.30±0.52) cm×(1.24±0.09) cm]明显大于黑麦[(13.20±0.35) cm×(0.82±0.02) cm],小黑麦花序长而粗,黑麦花序短而细;小黑麦花序的小穗数[(21.35±1.47)个]少于黑麦[(30.20±0.79)个];小黑麦每个小穗的小花数较多,为3~4朵,黑麦的小花数趋于稳定,每个小穗有2朵小花。从花序中部小穗的小花结构看,小黑麦下位护颖长[(1.27±0.11) cm]和宽[(0.26±0.03) cm]、上位护颖长[(1.30±0.09) cm]和宽[(0.23±0.04) cm]均显著大于黑麦下位护颖长[(1.04±0.05) cm]和宽[(0.08±0.01) cm]、上位护颖长[(0.94±0.10) cm]和宽[(0.06±0.01) cm];小黑麦中部小穗第1小花的外稃宽[(0.32±0.03) cm]、外稃高[(0.24±0.03) cm]和芒长[(8.35±0.51) cm]、第2小花的外稃宽[(0.35±0.04) cm]、外稃高[(0.25±0.05) cm]和芒长[(8.37±1.19) cm]极显著大于黑麦相应值[(0.26±0.01),(0.15±0.01),(5.50±0.19),(0.25±0.01),(0.17±0.01)和(5.18±0.23) cm];第1和第2小花的外稃长[(1.35±0.06),(1.37±0.06) cm]和内稃长[(0.84±0.04),(1.41±0.06) cm]均小于黑麦的外稃长[(1.49±0.05),(1.47±0.05) cm]和内稃长[(1.45±0.05),(1.47±0.04) cm]。小黑麦的穗粒数[(52.50±1.80)粒]显著低于黑麦[(58.50±2.50)粒] (P<0.05),但其穗粒重[(2.08±0.04) g]、粒重[(0.04±0.00) g]和籽粒宽[(3.04±0.32) mm]均极显著高于黑麦 (P<0.01),每个花序的籽粒不仅体积大,而且质量较重,其籽粒的生产性能高于黑麦。小黑麦籽粒呈椭圆形或长卵圆形,浅黄色,表皮皱缩,饱满度差;黑麦籽粒呈窄纺锤形,青灰色,表皮光滑,籽粒饱满。小黑麦和黑麦花序结构与籽粒性状的Pearson相关分析表明,小黑麦花序宽和花序基部小穗数与籽粒长显著正相关(P<0.05),花序长与籽粒宽极显著正相关(P<0.01),花序中部小穗的下、上位护颖宽分别与穗粒重和穗粒数极显著正相关(P<0.01);黑麦花序中部小穗第2小花的内稃长与籽粒长显著正相关(P<0.05),外稃高与穗粒数极显著负相关(P<0.01)。研究小黑麦和黑麦的花序结构和籽粒特征,对正确区分二者和了解其籽粒的生产性能具有重要意义,同时有利于小黑麦的示范推广。     

Critical Phase Transition of the Two-dimensional Microcanonical Ising Model by Cellular Automata Q2R Method

The authors construct a microcanonical ensemble system and analyzes the phase change of the two-dimensional Ising model Cellular Automata Q2R/WQ2R method. The result indicates that the numerical value simulation can show the spontaneous magnetization of two-dimensional crystal lattice in isolated system. The authors have observed the critical phase transition phenomenon and gotten the critical energy. The simulation of three-dimensional Ising model can be grounded on the method that this article establishes.     

Opportunities for investment into small ruminant breeding programmes in Brazil

The social contribution of goat and sheep industries is very important to many Brazilian families mainly in semi‐arid regions of the country. However, the productive chains of these two species in Brazil are unorganized and ultimately informal. On the other hand, there is potential for growth and development to which an upscaling of breeding programmes will be essential. Historically, many attempts to structure these programmes have been unsuccessful. Inadequate understanding of how to achieve genetic improvement often leading to distributing unsuitable exotic genetics among the producers is one of the reasons for the failure. Another important factor is related to the sources of funding and the priorities for the use of funds. According to the experience and the state of the art in Brazil, the priorities for funding must be in the characterization of the different systems and animal genetic resources, organization of information collection procedures and national databanks, training of technicians and producers and development of system to enable animal evaluation.     

无籽刺梨染色体数目观察

以无籽刺梨组培苗根尖为材料,探讨其染色体制片技术。结果表明,无籽刺梨根尖在常温下用0.003mol/L8-羟基喹啉溶液预处理6-8h或0.004mol/L8-羟基喹啉溶液预处理4-6h后,在预冷的卡诺固定液（冰醋酸：无水乙醇=3:1中）0℃下处理15min,经95%乙醇:15% Hcl=1:1的解离液处理5min或无水乙醇:36-38% Hcl=1:1处理6min,然后用卡宝品红染色15或20min,其镜检效果较佳;无籽刺梨的染色体数目为2n=2x=14。无籽刺梨染色体制片技术研究及其染色体数目的确定对其遗传改良工作有着重要的意义。     

D型产气荚膜梭菌ε毒素基因表达及其免疫保护作用的初步研究

利用PCR技术,从D型产气荚膜梭菌标准株(C60-2)染色体DNA中扩增出ε毒素基因。该基因产物大小为906 bp,序列分析结果表明,与GenBank报道的产气荚膜梭菌参考菌株ε毒素基因序列同源性大于99%。将扩增的ε毒素基因定向克隆到原核表达载体pET32a中,得到重组质粒pET32a-ETX,将重组质粒转化大肠杆菌BL21(DE3)plys中,经IPTG诱导后,SDS-PAGE分析可见大小为54 ku的特异条带;经Western blotting和ELISA检测结果表明,表达的ε毒素能与抗天然ε毒素抗体发生特异性反应,说明ε毒素蛋白具有较好的反应原性。将表达的ε毒素蛋白用0.4%的甲醛溶液制成类毒素疫苗,免疫小鼠后,具有一定的保护力,这表明该重组菌株有望成为产气荚膜梭菌基因工程类毒素疫苗的候选菌株。     

细毛羊黑素皮质激素受体1(MC1R)基因与毛色表型的研究

为了研究黑素皮质激素受体1(MC1R)基因与黑色素生成的关系及该基因突变导致毛色发生改变的机理,研究采用RT-PCR和PCR等技术克隆得到了白色东北细毛羊MC1R基因长1 093 bp的cDNA片段,编码364个氨基酸,其中包括70个氨基酸信号肽和294个氨基酸的成熟肽,具有7个跨膜结构域。结果表明:细毛羊cDNA与绵羊、牛、马、人、小鼠、犬等同源性均大于91%,氨基酸序列与其他动物的同源性高于89%;除绵羊外与其他动物相比有5处发生突变,且这5处突变均位于MC1R蛋白跨膜结构区;而细毛羊和绵羊之间只有1处发生突变,由K→M,同源性达98.97%。说明细毛羊与绵羊的亲缘关系最近。