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1.
猪流行性腹泻病（porcine epidemic diarrhea,PED）是一种高度接触性肠道传染性疫病,主要危害1周龄以内的仔猪,仔猪感染死亡率高达100%,是目前危害世界养猪业的主要疫病之一。本研究旨在制备针对猪流行性腹泻病毒S蛋白的特异性纳米抗体并鉴定其结合活性。作者原核表达并纯化PEDV S1蛋白,将纯化后的PEDV S1重组蛋白免疫双峰驼,第4次免疫后分离其外周血淋巴细胞,提取淋巴细胞RNA,反转录得到cDNA,通过巢式PCR扩增VHH片段,并构建至pCANTAB-5E载体中,电转化至TG1感受态细胞,得到VHH噬菌体抗体展示文库;随后,对构建的噬菌体抗体展示文库进行救援和3轮富集,利用噬菌体展示技术从中筛选针对PEDV S蛋白纳米抗体,通过ELISA验证筛选的纳米抗体的特异性和结合力。通过Western blot和间接免疫荧光验证纳米抗体与PEDV的结合活性。结果显示：成功表达并纯化PEDV S1蛋白,经4次免疫后,双峰驼血清中的特异性抗体效价达到了1∶256 000。构建的噬菌体展示文库的库容量为2.1×107,阳性率85%;对噬菌体展示文库3轮的淘选富集后,最终筛选出6株氨基酸序列不同的纳米抗体,ELISA结果显示,6株纳米抗体均对PEDV S1重组蛋白具有良好的结合力与特异性。随后验证了Nb3能够与PEDV结合,表明其具有良好的活性。成功筛选到针对PEDV S1蛋白的特异性纳米抗体,所筛选纳米抗体有望用于PED的诊断和治疗,同时为PEDV的致病机制研究提供抗体材料。 相似文献
2.
为明确施氮量对酿酒小麦原粮品质和酿酒品质的影响,以绵麦902和中科紫糯麦168（糯性）两个小麦品种为材料,设置6个施氮量（0、45、90、135、180、225 kg·hm-2）,对小麦产量、原粮品质和酿酒品质进行了分析。结果表明：（1）两供试小麦品种的产量和有效穗数无显著差异;随施氮量增加,两品种的有效穗数、穗粒数及产量增加,均在施氮225 kg·hm-2达最大值。（2）随施氮量增加,两个小麦品种的籽粒蛋白质、脂肪和灰分含量增加,均在135 kg·hm-2处理下较高;淀粉含量和粉质率降低,绵麦902直链淀粉含量和直支比均以180 kg·hm-2处理最高,分别为22.6%和0.641,支链淀粉含量以45 kg·hm-2处理最高,为 42.6%;中科紫糯麦168直链淀粉含量和直支比均以45 kg·hm-2处理最高,分别为3.9% 和0.058,支链淀粉含量以90 kg·hm-2处理最高,为69.3%。（3）与中科紫糯麦168相比,绵麦902出酒率较高,总酸、总酯含量较低,增施氮肥显著降低总酸含量,显著增加总酯含量;施氮90~135 kg·hm-2范围内两品种出酒率较高,总酸和总酯含量较协调;（4）相关分析表明,出酒率与直链淀粉含量和粉质率呈显著和极显著正相关,与脂肪含量呈极显著负相关;总酸含量与总淀粉、支链淀粉和脂肪含量呈显著正相关,与粉质率呈显著负相关;总酯含量与灰分含量呈显著负相关。本研究认为,绵麦902和中科紫糯麦168酿酒品质各具优势,绵麦902出酒率高,中科紫糯麦168具有更好的产酯特性;在90 ~135 kg·hm-2施氮范围内,两品种蛋白质含量较适宜,总淀粉和支链淀粉含量较高,灰分含量高,脂肪含量适宜,出酒率和总酸含量也较高,是川西平原酿酒小麦较佳施氮量范围。 相似文献
3.
A long-term (1983–2000) global dataset of Earth’s surface daily-integrated UV exposure was developed from a combination of ISCCP-D1 3 h reflectance measurements (in order to resolve the diurnal variation of cloud conditions) and TOMS total ozone amount. The inversion algorithm developed in our previous study was employed with modifications addressing the conversion of visible reflectance to UV albedo and narrowband UV albedo to broadband albedo over the range of 280–400 nm. Validation of the product was carried out using ground-based measurements at six stations. In general, good agreements between the estimated and measured daily UV exposure are found at most stations; the relative mean and root mean square (RMS) difference varies from 3 to 14% and from 20 to 45%, respectively. Among the stations, San Diego has a fairly low mean difference (9%) and the lowest RMS difference (33%), owing to the prevailing clear sky or uniform cloud cover condition. The RMS difference increases with cloud amount, which is largely caused by mismatch between satellite and ground-based measurements. The effect of diurnal variation in atmospheric opacity associated primarily with cloud on the estimation of daily erythemal UV doses is investigated with both ground-based measurements and ISCCP-D1 data. It is found that daily erythemal UV doses estimated from only a noontime satellite “snapshot” may incur errors larger than 20%, which may be reduced for long-term averaging. 相似文献
4.
大花黄牡丹遗传多样性的SRAP分析 总被引：2，自引：0，他引：2
应用SRAP标记对西藏特有植物大花黄牡丹的遗传多样性进行研究。用16对引物从5个自然居群79个单株中共检测到396个有效位点,其中多态性位点357个。在物种水平上,多态位点百分率(Ppl)为90.15%,Shannon表型多样性指数(Ηsp)平均为0.2521;居群水平上的Ppl为31.82%,Shannon表型多样性指数(Ho)为0.0694～0.3428,平均值(Ηpop)为0.1307。上述遗传参数表明,大花黄牡丹具有丰富的物种遗传多样性,5个居群中自然居群C的遗传多样性最高(Ppl=82.32%,Ho=0.3428)。据AMOVA分析结果,总的变异中有41.58%的变异存在于居群间,58.42%的变异存在于居群内,居群分化较显著(ΦST=0.4158,P<0.001),由POPGENE1.32得到的居群间遗传分化系数GST(0.4309)和Shannon表型多样性指数计算的居群间遗传多样性所占比例(0.4816)也表明了类似的遗传结构。Mantel检测表明地理距离和Nei’s遗传距离间相关不显著(P>0.05)。利用NTSYSPC(2.1)软件构建大花黄牡丹5个居群79个个体的UPGMA聚类图,遗传相似系数变幅在0.47～0.99,大多数居群内的个体表现出较为密切的亲缘关系(如居群B,D,E),但也有一些居群的个体未聚在一起(如居群C)。依据大花黄牡丹居群遗传变异特点,初步探讨其保护和利用策略。 相似文献
5.
采用高寒草甸、高寒草原、高寒沼泽化草甸和温性草原4种西藏高原典型草地类型地上生物量定点观测数据,分析其地上生物量季节动态变化特征和生长规律。结果表明,高寒沼泽化草甸地上生物量最高,其中围网草地年均地上生物量达384.45 g·m-2,比无围网草地地上生物量高73%,且是温性草原类草地生物量的6倍,是高寒草甸和高寒草原类草地的12~14倍,与自由放牧相比,围栏禁牧措施可以明显提高草原地上生物量,是改良退化草地最有效的措施之一;温性草原草地生产力大于高寒草甸和高寒草原,城市附近山地草地生物量明显大于远离城市的地区,表明城市化进程降低了天然草地放牧强度,是恢复退化草地生产力的有效途径之一;属半干旱气候类型的西藏高原中部,降水是制约草地植被生长的主要因子;草地地上生物量的绝对增长速率和相对增长速率季节动态均在生物量达到高峰期前为正增长,之后为负增长。区域水热条件差异及其季节性变化导致了不同草地类型或同一类型不同区域的草地最快生长期出现的时间存在一定差别。 相似文献
6.
Feng-lian LÜ Miao-miao HOU Hong-tao ZHANG Asif Khan Muhammad Ayaz Ciren QIANGJIU Chang-lu HU Xue-yun YANG Ben-hua SUN Shu-lan ZHANG 《农业科学学报》2019,18(1):169-178
A high crop yield with the minimum possible cost to the environment is generally desirable. However, the complicated relationships among crop production, nitrogen (N) use efficiency and environmental impacts must be clearly assessed. We conducted a series of on-farm N application rate experiments to establish the linkage between crop yield and N2O emissions in the Guanzhong Plain in Northwest China. We also examined crop yield, partial factor productivity of applied N (PFPN) and reactive N (Nr) losses through a survey of 1 529 and 1 497 smallholder farms that grow wheat and maize, respectively, in the region. The optimum N rates were 175 and 214 kg ha–1 for winter wheat and summer maize, respectively, thereby achieving the yields of 6 799 and 7 518 kg ha–1, correspondingly, with low N2O emissions based on on-farm N rate experiments. Among the smallholder farms, the average N application rates were 215 and 294 kg ha–1 season–1, thus producing 6 490 and 6 220 kg ha–1 of wheat and maize, respectively. The corresponding PFPN values for the two crops were 36.8 and 21.2 kg N kg–1, and the total N2O emissions were 1.50 and 3.88 kg ha–1, respectively. High N balance, large Nr losses and elevated N2O emissions could be explained by the overdoses of N application and low grain yields under the current farming practice. The crop yields, N application rates, PFPN and total N2O for wheat and maize were 18 and 24% higher, 42 and 37% less, 75 and 116% higher, and 42 and 47% less, correspondingly, in the high-yield and high-PFPN group than in the average smallholder farms. In conclusion, closing the PFPN gap between the current average and the value for the high-yield and high-PFPN group would increase crop production and reduce Nr losses or the total N2O emissions for the investigated cropping system in Northwest China. 相似文献
7.
Guo-Hua Liu Dong-Hui Zhou Wei Cong Xiao-Xuan Zhang Xin-Chun Shi Ciren Danba Si-Yang Huang Xing-Quan Zhu 《Tropical animal health and production》2014,46(1):257-259
Swine influenza A virus (SIV) is zoonotic pathogen that can be acquired by food-borne transmission because food animals, for example pigs, are recognized as a reservoir. The objectives of this study were to determine the seroprevalence of anti-SIV (H1N1 and H3N2) in Tibetan pigs in Tibet Nationality Autonomous Region, China, a region with cold weather and high altitude. A total of 421 serum samples were randomly collected from Tibetan pigs in Tibet and were evaluated for antibodies against SIV using enzyme-linked immunosorbent assay. Overall, 52 % (219/421) of the animals was positive for H1N1, 16.9 % (71/421) positive for H3N2, and 8.8 % (37/421) positive for both H1N1 and H3N2. The results of the present survey indicated that SIV is highly prevalent among Tibetan pigs in Tibet, China. The results of the present investigation have implications for the ongoing control of SIV infection in Tibetan pigs in Tibet, China and elsewhere. 相似文献
9.
为了解拉萨市鸡沙门氏菌病的流行情况,探讨主要发病原因,2015年4月至2016年9月,对拉萨市5个县(区)12个集约化养鸡场进行了流行病学调查。结果显示:所采集的1 203份样品中,共检测出沙门氏菌589株,阳性率达48.96%,说明拉萨市鸡沙门氏菌感染较为普遍;在所检测的样品中,种鸡、种蛋检出率分别为41.00%和37.00%,说明种鸡沙门氏菌带菌现象较为严重;病鸡样品检出率为70.54%,其中成年鸡为57.63%、鸡舍环境样本阳性率为16.67%,饲料阳性率为11.60%,说明这些都是造成沙门氏菌水平传播的主要风险因素。 相似文献
10.
西藏人工造林作业区土壤养分特征研究 总被引：6，自引：0，他引：6
为了掌握西藏拟造林作业区的土壤养分状况,对6个地市524个造林作业区的土壤样本进行了养分测定和分析。结果表明:(1)土壤全钾、有效磷、有机质和速效钾均处在"稍缺―极缺"水平:平均含量分别为6.26 g kg~(-1)、8.7 mg kg~(-1)、17.81 g kg~(-1)和83.6 mg kg~(-1),全氮和全磷处在"中等―稍缺"水平:平均含量分别为1.39 g kg~(-1)和0.72 g kg~(-1),碱解氮条件最好:平均含量为214.1 mg kg~(-1),全钾条件最差。(2)6地市除碱解氮外,土壤中分别存在2至5个养分元素的缺乏,多数作业区全钾、速效钾和有效磷不足。阿里地区最缺有机质,仅5.08 g kg~(-1),日喀则市、拉萨市和林芝市最缺全钾,仅5.19~6.42 g kg~(-1),山南市和昌都市最缺有效磷,仅3.9~5.4 mg kg~(-1)。此外,拉萨市、山南市和阿里地区多数作业区全氮不足,阿里地区、日喀则市和昌都市全磷不足,除昌都市外各地市有机质不足的作业区居多。(3)地市间土壤养分含量差异显著,但速效钾、有机质在日喀则市、拉萨市和山南市间差异均不显著。总体而言,西藏造林作业区土壤养分状况较差,通过对西藏造林作业区土壤养分的特征分析,可为作业区造林后树木生长状态的成因查寻提供科学依据,为进一步提高造林质量提供基础数据。 相似文献