高粱茎尖和幼穗细胞悬浮系的建立

建立有效可靠的细胞悬浮培养方法对进一步开展原生质体培养和转基因研究具有重要意义。本研究以茎尖和幼穗作为外植体,采用愈伤振荡培养法、匀浆收集培养法和直接培养法三种方法进行了细胞悬浮系建立的方法研究。结果表明:与茎尖相比,幼穗是更适宜开展高粱细胞悬浮培养的理性外植体。采用三种培养方法均可建立幼穗细胞悬浮系,其中幼穗愈伤振荡培养法最为稳定可靠,幼穗匀浆收集培养法和直接培养法的稳定性稍差,但获得的细胞悬浮系生长状态较好,有利于进一步开展增殖继代培养。结果还表明,茎尖愈伤振荡培养法也是一种稳定可靠的细胞悬浮系制备方法,但茎尖匀浆收集培养法稳定性稍差,而直接培养法效果最差不宜采用。     

天津市武清区秸秆综合利用现状及问题

积极探索秸秆的综合利用途径,大力推进秸秆资源化利用,发挥其应有的经济、生态、社会和环境效益,对保持社会协调、稳定发展,推进农村新能源建设,保障社会经济生活的正常秩序,具有重要的政治、经济和社会意义。在介绍秸秆利用价值的基础上,分析了天津市武清区秸秆利用现状和存在的问题,并提出相关的建议措施,以推进秸秆的综合利用进程。      

玉米生育期空间插值方法比较

采用合适的空间插值方法可以估计全国主产区玉米生育期的空间分布情况,从而指导不同地区的种植生产。该文通过比较反距离加权法、径向基函数法、克里格法等插值方法的异同,以调查县夏播玉米5个阶段的生育期为数据源,对黄淮海夏播玉米区生育期的数据进行空间插值处理,并使用交叉验证对表面精度进行分析。结果表明：播种期、出苗期和成熟期的最适合插值方法为径向基函数法,其均方根预测误差分别为5.077、5.320、5.243 d,拔节期和抽雄期的最佳插值方法为反距离加权法,其均方根预测误差分别为7.826、6.403 d;播种期和出苗期由西南至东北逐渐延后,其余阶段生育期以东南至西北为中轴线向两侧逐渐延后。     

Cytogenetic survey of Holstein bulls at a commercial artificial insemination company to determine prevalence of bulls with centric fusion and chimeric anomalies

OBJECTIVE: To determine prevalence of Holstein bulls with chromosomal anomalies, particularly the 1/21 centric fusion (CF), at a commercial artificial insemination (AI) company in the United States. DESIGN: Cross-sectional cytogenetic prevalence study. ANIMALS: All 606 Holstein bulls at a commercial AI company were cytogenetically screened to detect CF, chimerism, and other chromosomal abnormalities. PROCEDURE: Lymphocytes from heparinized blood samples were cultured by standard cytogenetic techniques, and chromosome spreads were prepared for microscopic examination. Chromosomal abnormalities were detected by examining 10 chromosome spreads per bull. Pedigree analysis was performed. RESULTS: None of the bulls had any type of CF. However, 6 bulls were identified as chimeras (i.e., contained lymphocytes with male [XY] and female [XX] chromosomes). One bull was sire or maternal grandsire to 85 of the bulls tested, and 739 of 1,212 (61%) sire and maternal-grandsire possibilities were accounted for by just 18 bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results supports previous indications that CF is extremely rare in Holstein bloodlines available commercially via AI in the United States. However, chimeric bulls are more common, and they reportedly have decreased reproductive performance. Therefore, identification of chimeric sires in the AI facility reported here and the possibility of de novo onset of CF at any time indicates that early cytogenetic screening should be encouraged for prospective bulls intended for use in AI programs.     

牛结核γ-干扰素ELISA检测方法在检疫工作中的应用

为评价牛γ-干扰素ELISA检测方法检测牛结核的效果及国产试剂盒的检测效果,本试验首先将国产试剂盒与Prionics试剂盒对42份相对阳性的样品和105份相对阴性的样品进行对比研究。然后对5个规模化牛场的3000头奶牛首先进行国产单纯结核菌素颈部皮内变态反应试验,3天后选取皮内变态反应阳性和可疑及部分阴性牛共418头,进行牛γ-干扰素试验。结果国产试剂盒对阳性和阴性样品的检测敏感性和特异性分别为95.2%和100%,与Priobics试剂盒的符合率为99.3%。表明国产试剂盒与进口试剂盒的检测能力一致,牛γ-干扰素检测方法准确可靠。5个牛场的3000头奶牛单纯结核菌素颈部皮内变态反应试验阳性为138头,可疑105头。γ-干扰素试验对418头奶牛的检测,其中阳性74头,与颈部皮内变态反应（可疑牛暂时视为阴性）的符合率为60.5%。     

柱花草刈割次数与生产性能的关系

对格拉姆柱花草的刈割次数与生产性能关系进行了两年时间的研究,结果表明:不同年度、不同次数刈割对生产性能影响很大,当年刈割一次比刈割两次产草量增长44%—68%,粗蛋白产量增长40%左右;第二年刈割两次比刈割一次产草量增长4.8%,粗蛋白产量增长52%,而比刈割三次产草量增长17%,粗蛋白产量增长9%。     

光棘豆单细胞培养再生植株

由光棘豆种子无菌苗的胚轴和子叶诱导的愈伤组织建立起细胞悬浮系。由悬浮系分离出单细胞。单细胞在含有1～2mg/L 2,4—D的2/3MS培养基中采用振荡和静止两种方法培养。结果表明。振荡培养愈伤组织再生频率较高,所需时间较短。单细胞再生的愈伤组织转入分化培养基后分化出芽。幼苗转入含有IBA和IAA的1/2MS培养基中生根,成为完整的再生植株。在分化培养基中,只有瘤状愈伤组织能够分化出芽。并且较高浓度的细胞分裂素(6—BA或KT)或6—BA与ZT结合使用对愈伤组织的分化是有利的。     

刚棘颚口线虫的扫描电镜观察

刚棘颚口线虫扫描电镜显示：头球顶端有两片半球形的大侧唇，大侧唇背面有1对双乳突和1个头感器。在轮节皮棘第6-7排或第8-9排或第10-11之间各有1对颈乳突，与樊氏等及古贺正崇等描述颈乳突位置有所差异。并观察到雄虫尾端长交合刺的皮纹上有细小的凹陷小乳，其顶端有开口处；有2对尾乳突。雌虫阴门位于虫体腹面中线之后；尾端前腹面有半月状的肛门，有1对尾乳突。其中头钩、体棘、交合刺和尾乳突等形态特征与前人记述相似。     

硫的营养作用及在养殖业的应用

1硫在体内的分布大多数动物的含硫量按活体质量计算是0.16%~0.28%,且随年龄而增加,这大概是由于肌肉蛋白质的合成加强,以及硫在毛发和羽毛中的积累。硫元素分布在动物体内的各个细胞中,主要以有机硫的形式存在于蛋氨酸、胱氨酸和半胱氨酸中。此外,还存在于生物素、硫氨素以及黏     

Development of a loop-mediated isothermal amplification assay for rapid, sensitive and specific detection of a Campylobacter jejuni clone

Loop-mediated isothermal amplification (LAMP) assay is a simple, rapid and specific detection method and has been used for detection and identification of different Campylobacter species. In this study, we develop a LAMP assay specific for detection of a particular clone (clone SA) of Campylobacter jejuni, associated with the vast majority of recent sheep abortions in the U.S. Using a set of specific primers for C. jejuni IA3902 (a clone SA isolate) and genomic DNA or boiled cell extract as template, the target DNA was amplified at 63 °C for 50 min in a water bath. A positive reaction was identified visually as white precipitate or fluorescence under UV, and confirmed by gel electrophoresis. Detection limit of the assay was comparable to that of conventional PCR. The LAMP was shown to be specific for detection of clone SA when tested on a number of C. jejuni strains of different genetic backgrounds. Applicability of the LAMP assay for specific detection of clone SA was demonstrated in animal tissues experimentally infected with IA3902 or genetically diverse C. jejuni strains. Since clone SA is the predominant cause of sheep abortions in the U.S. and is a zoonotic pathogen, the LAMP assay may be a valuable detection tool in future epidemiological studies.