抗稻瘿蚊品种多抗1的抗性遗传分析及抗性基因定位

稻瘿蚊是亚洲稻区主要害虫,采用抗虫品种进行防治是最理想的方法。1993～1995年,广东省农科院与国际水稻研究所有关专家紧密合作,对能抗华南4个稻瘿蚊生物型的品种多抗1作进一步抗性遗传分析,确认多抗1对中国稻瘿蚊生物型1和4的抗性受显性单基因控制,这个基因暂定名为GM—6(t)。以多抗1×丰银占1组合的F3代160个家系作基因标记,据DNA库分离个体分析(BSA)原理,用随机扩增多态性DNA(RAPD)标记物OPM6(1.4kb),首次成功地标记了这个抗性基因。随后多态性扩增产物经~(32)p标记,用作探针,检测另一个参考作图群体IR64×Azucena,将这个抗性基因定位在水稻第4条染色体上,位于RG214和RG163两个DNA限制性片段长度多态性(RFLP)标记之间。应用这些分子标记辅助选择有可能不必通过稻瘿蚊的直接筛选,快速准确地选育抗稻瘿蚊品种或进行抗性基因累加。     

立枯丝核菌侵染玉米的研究

 用获自水稻及玉米的立枯丝核菌(Rhizoctonia solani Khn) AG-11A接种玉米发生典型纹枯症状,其致病力显著强于AG-4。玉米拔节期,上位叶鞘抗性较强,抽雄及抽丝期抗性减弱,下位叶鞘无论在拔节期或抽雄、抽丝期,均较上位叶鞘感病。接种玉米后8小时,形成侵染垫及附着胞,从这些结构上形成侵入钉侵入,AG-4侵染上位叶鞘时,常以菌丝直接穿透表皮或从气孔侵入。在去掉菌体的叶鞘表面,发现有周边光滑或稍破损的侵入孔。接种后12小时,在叶鞘细胞中发现菌丝,它们在穿过细胞壁进入邻近细胞时,明显变细。接种后16小时,新生出的菌丝从气孔成丛出现。     

稀土对增强棉花抗枯萎病的作用及其机制

 棉花枯萎病(Fusarium oxysporum f.sp.vasinfectum)是我国棉区的毁灭性病害之一。国内外除采用以抗病良种为主的综合防治外,新近还采用见效快的生物和化学物质如乙磷铝(Phosethy-AL)、氟乐灵(Trifluralin)诱导棉花对枯萎的抗性,我国占世界储量80%的稀土能促进棉花增产10%左右,能否诱导棉花对枯萎病的抗性?     

日本对虾内陆养殖的实验室模拟研究

我们将日本对虾进行实验室桶养作模拟内陆养殖试验。发现日本对虾可以顺利地养殖到体长５－７厘变,然后短人存活率急剧降低,这一现象与我们海边虾塘养殖所得到的结果极为一致,我们称之为“５－７”现象。     

同步辐射软X射线对家蚕生理生化性状的影响

采用一定剂量同步辐射（ＳＲ）软Ｘ射线辐照催青卵及蚕蛹,利用ＰＡＧＥ对蚕卵及蛹子代的蛋白质和酯酶同工酶进行分析,结果发现谱带数目及活性的变化,茧质调查与对照相比也有差异。首次证明ＳＲ软Ｘ射线对家蚕的生理生化性状有一定影响     

白砂糖贮存期质量管理的体会

受原料甘蔗生长规律的影响 ,除了极少数从事炼糖生产的糖厂之外 ,绝大多数制糖企业都是季节性地生产白砂糖。产品从生产到销售出去 ,往往要经历几个月甚至一年的贮存期。白糖贮存质量的好坏 ,直接影响到其销售 ,影响到企业的经济效益。如何提高白砂糖仓贮质量 ,防止变质、降级 ,避免客户投诉 ,是值得众多糖厂共同研究的课题。1　贮存期白砂糖常见的质量变化1 .1　色值增加 ,俗称“返黄”。白砂糖在存放过程中 ,其所含非糖杂质 (如酚类物质、铁化合物等 )易受空气氧化而使色泽逐渐变黄。白砂糖返黄的机理是比较复杂的 ,霍汉镇对此有较系统的…     

提高晋南牛肉用性能的杂交组合研究（二报）：杂交一代与晋南牛肥育性能测定

平均15月龄的夏晋、西晋、利晋杂交1代和晋南阉牛各4头，按美国NRC肉牛营养标准配合日粮，经100天育肥后屠宰（约18月龄）测定其肉用性能。复晋、西晋、利晋和晋南牛平均日增重分别是904．5±9．12，838．5±6.2，824．3±3．29和618．7±16．6克；每增重1千克活重消耗总可消化养分6．11，7.01，7.15和7.83千克；消耗粗蛋白质846．7，931．1，949．1和1047.9克；宰前活重分别为421．5±7.94，412，0±7．53，404.3±10．52和318．0±11．63千克；屠宰率平均分别为57．5．56．96，55．97和51．69％；肉骨比分别为4．65，4．35．5．12和4．1；体腔脂肪总重分别为15．85，11．15，11．70和17.35千克。结果表明，杂交牛肉用性能均有较大提高。     

ECOLOGY OF MYCOPLASMAS IN CLINICALLY HEALTHY CATS

Mycoplasmas were isolated from various sites and organs of a series of 319 clinically healthy cats. They include M. felis, M. gateae, M. Arginini, A. laidlawii, feline ureaplasmas, M. pulmonis, M. arthritidis, and M. gallisepticum. In addition, there were 10 strains of mycoplasmas which could not be identified with the specific antiserums by growth inhibition tests. Antibody against M. felis was demonstrated by haemagglutination-inhibition and complement-fixation tests in cats which were over 6 months of age. However, no such antibody against M. felis was detected in animals which were less than 6 months old. No antibody against A. laidlawii, M. gateae, M. arginini and feline ureaplasmas was demonstrated by the same serological methods. The significance of these mycoplasmas in cats is described.     

Catheters: a review of the selection, utilisation and complications of catheters for peripheral venous access

Intravenous catheters are used for the administration of medications and fluids and are an integral part of veterinary practice. The aim of catheter use is to optimise administration of medication and minimise complications such as thrombus formation, thrombophlebitis and sepsis. Catheters made from teflon are less flexible, less durable and stimulate more tissue reaction than polyurethane or silicon. However silicon catheters are more expensive and complicated to insert. Generally, for veterinary practice, the biostability and cost of polyurethane catheters make them preferable for short and long-term use. The smallest diameter catheter should be selected to minimise internal vessel wall contact and irritation without compromising medication delivery. The site of insertion varies with individual preference, vessel access and patient compliance. The jugular, cephalic, saphenous, ear, lateral thoracic and subcutaneous abdominal veins are accessible. Hair removal and a thorough aseptic skin preparation should be performed prior to catheter insertion. Daily maintenance is required to detect complications and maximise catheter longevity. Potential complications include thrombus formation, thromboembolism, bacterial colonisation and septicaemia, blood loss and air embolism. Permanent or transient skin dwelling bacteria are commonly isolated if sepsis occurs. The development of novel antiseptic and antibiotic impregnated catheters may reduce the complications associated with catheter infection in the future.