Distribution and hybridization patterns of the insertion element IS900 in clinical isolates of mycobacterium paratuberculosis

Reference strains and 31 clinical isolates of M. paratuberculosis, mainly from goats, were analysed for restriction fragment length polymorphism (RFLP). Restriction digests of bacterial DNA were hybridized with a repetitive insertion sequence, IS900, to obtain banding patterns for comparison of strains. Twenty-five of the 31 field-strains hybridized with IS900, and five hybridization patterns were identified. It was not possible to identify specific patterns for goat strains of M. paratuberculosis. Four hybridization patterns were similar, whereas the fifth pattern of a sheep strain diverged considerably in position and number of band. Six goat strains failed to hybridize with IS900, and the absence of IS900 was verified by the polymerase chain reaction and hybridization with an oligonucleotide probe. The six IS900-negative goat strains had diverging phenotypic properties, and the identification of these strains is discussed. The present study shows that M. paratuberculosis strains infecting goats are genetically similar to cattle strains and that IS900 is a specific genetic element for identification of M. paratuberculosis.     

超高产水稻新组合Y两优900百亩方15.40t/hm^2高产栽培技术研究

Y两优900是以广适性光温敏不育系Y58S为母本,籼粳杂交选育的偏籼型恢复系R900为父本配组育成的超高产杂交稻新组合,具有根系发达、穗大粒多、结实率高、株叶形态理想、熟期适中、适应性广、高产稳产、优质多抗等特点。2014年在湖南溆浦对该组合进行了较大面积攻关试验,创造了6.84 hm^2面积单产15.40 t/hm^2的世界纪录。介绍了Y两优900的特征特性,并详细阐述了Y两优900百亩攻关片单产达15.40 t/hm^2的高产栽培技术。     

高氮密植栽培对湘两优900产量形成及氮利用效率的影响

为探明湘两优900在热带稻区的高产性和适应性,在海南三亚进行4个施氮水平(0、150、225、300 kg·hm^-2)和2个移栽密度(25.0×10⁴、16.7×10⁴ hills·hm^-2)大田栽培试验,研究施氮水平和移栽密度对湘两优900产量形成和氮肥利用率的影响。结果表明,施氮水平和移栽密度对湘两优900产量影响显著,产量随着施氮水平和移栽密度的提高而显著增加,以施氮量300 kg·hm^-2与移栽密度16.7×10⁴ hills·hm^-2组合的产量最高(15.32 t·hm^-2),其增产优势主要表现为有效穗数多,地上部干物重和叶面积指数(LAI)大,叶绿素含量和净光合速率(Pn)高。施氮水平与移栽密度对氮肥吸收利用效率有影响,且施氮水平起显著作用。施氮量为300 kg·hm^-2时,氮肥吸收利用率最大(44.5%),增加施氮量能显著提高氮肥利用率,同时也会显著降低氮素吸收效率、氮生理效率、氮肥效率。从产量和氮肥利用效率综合考虑,施氮量300 kg·hm^-2与移栽密度25.0×10⁴ hills·hm^-2是本试验条件下的最优密肥组合。本研究结果为超级杂交稻在热带稻区(海南)推广应用提供了科学依据。     

水稻香两优68抛栽产量7.5t/hm~2的生育特点及其关键技术

优质两系杂交早稻香两优 68抛秧栽倍 ,具有生育期适宜、分蘖早且多、生长势强、有效穗足、产量高等特点。实现产量7.5t/hm2 的关键技术是有效合理催芽、精量播种、施用壮秧剂、适龄足苗匀抛和科学运筹肥水等     

Quantitative real-time PCR and culture examination of Mycobacterium avium subsp. paratuberculosis at farm level

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease in ruminants and may contribute to Crohn's disease in humans. The aim of this study was to determine the occurrence and quantity of MAP in cattle feces and milk in the Iranian context. In addition, we evaluated the effect of cattle age as well as farming system as risk factors contributing to MAP load. For this, a total sample of 373 consisting of 150 cattle feces (CF), 150 individual cow's milk (ICM), as well as 73 bulk-tank milk (BTM) was collected randomly and regardless of the cattle health status. The samples were assayed using F57 quantitative real-time PCR (qPCR) and culture method. According to the results of qPCR which was found ∼10 times more sensitive than culture assay, MAP was detected in 68.66% (103/150) of the CF, 12% (18/150) of the ICM and 52.05% (38/73) of the BTM samples. In contrast to the previous reports, the quantity of MAP in the BTM (2.03–5.97 log cfu/50 ml) was statistically (p < 0.01) higher than the ICM (0.90–1.97 log cfu/50 ml). Data suggested a direct relation (p < 0.01) between the cattle age and the quantity of MAP in the CF samples, while the relation was not statistically significant (p > 0.05) for the ICM. In addition, MAP load in the BTM samples obtained from traditional farms was significantly (p < 0.01) higher than that of the industrial ones, while the differences in CF and ICM was not significant (p > 0.05).     

Distribution of IS900 restriction fragment length polymorphism types among animal Mycobacterium avium subsp. paratuberculosis isolates from Argentina and Europe

Sixty-one Mycobacterium avium subsp. paratuberculosis isolates from cattle and deer from the Buenos Aires province, an important livestock region in Argentina, were typed by restriction fragment length polymorphisms (RFLP) analysis based on IS900. Four different RFLP patterns (designated ‘A’, ‘B’, ‘C’ and ‘E’) were identified in BstEII digests of genomic DNA. The most frequently observed type, pattern ‘A’, was found in 46 isolates (75%). The second, pattern ‘E’, included 8 isolates (13%), while the third, pattern ‘B’, included 6 isolates (10%). Pattern ‘C’ was found for only one isolate. All of the deer isolates were classified as pattern ‘A’, while cattle isolates represented all four RFLP patterns. Twenty-one isolates representing the four different BstEII-RFLP patterns were digested with PstI. Twenty isolates showed identical PstI-RFLP pattern. BstEII-RFLP patterns from Argentine cattle and deer were compared with patterns found in cattle, goat, deer, rabbit, and human isolates from Europe. The most common pattern in Argentina, pattern ‘A’, was identical to a less frequently occurring pattern R9 (C17) from Europe. The other Argentine patterns ‘B’, ‘C’ and ‘E’, were not found in the Europe. These results indicate that the distribution of M. avium subsp. paratuberculosis genotypes in the Buenos Aires province of Argentina is different from that found in Europe.     

优质杂交早稻香两优68的选育与应用

通过选用优质,早熟两用核不育系香１２５Ｓ与早籼品系Ｄ６８配组而育成的香两优６８,是一个高产,优质的两系杂交早稻组合,１９８８年２月通过湖南品种审定,填补了我国优质杂交早稻的空白,在长江流域作早稻种植,具有很好的应用前景。     

朱砂叶螨为害前后抗、感木薯品种叶组织营养物质含量差异分析

为了明确营养物质在木薯抗螨性中的重要作用,在获得遗传稳定的抗、感螨参照标准木薯品种的基础上,采用分光光度法开展了朱砂叶螨为害前后抗、感螨参照标准木薯品种叶组织中营养物质含量的差异分析。结果表明：朱砂叶螨为害1、4、8 d的抗螨参照标准木薯品种C1115叶组织中的游离氨基酸（FAA）、可溶性糖（WSS）、可溶性氮（SN）含量均显著降低,分别是为害前的69.69%、69.29%和63.42%,73.16%、73.71%和72.75%,45.97%、46.21%和46.13%（P<0.05）;但糖氮比（S/N）显著升高,是为害前的159.15%、159.46%和157.83%（P<0.05）,游离脯氨酸（Pro）含量无显著变化。螨害1、4、8 d的感螨参照标准木薯品种BRA900叶组织中的FAA含量和WSS含量与为害前无显著差异,SN含量显著升高,是为害前的148.50%、148.73%和148.77%;S/N显著降低,是为害前的62.61%、61.48%和61.92%;Pro含量显著升高,是为害前的373.82%、367.33%和362.61%,但为害前后无显著性差异（P<0.05）。     

HVI900仪测试棉纤维品质的误差及其控制

对ＨＶＩ９００仪测试棉纤维品质的误差及其控制进行了研究。结果表明，（１）ＨＶＩ９００仪本身存在测试误差；（２）各品种与标准棉样纤维品质的变异趋势基本一致，但前者的变异程度远大于后者；（３）纤维品质中，以比强度的变异系数最大，麦克隆值的变异系数最小；（４）中期花的纤维品质好于混合花，且变异程度小于混合花。为了使纤维品质的测定结果具有一定的精度，中期花和混合花的测试次数分别以１０次和２０次为宜     

基于物联网的家用电灯开关无线控制系统设计

设计了一种基于物联网的家用电灯智能无线控制系统。系统设计了以Cortex-M3内核的stm32处理器作为系统主机控制器电路,采用STC89C52RC单片机的从机电路,实现开关控制功能和检测电流传感器的输出数据。系统以手机短信和NRF24L01实现射频通信,系统的用户端与控制端的信息传递通过GSM模块-SIM900A的短信接收与发送完成,从而实现了智能无线控制控制系统中的手机与家用电器的物物连接。