改良背主动脉注射法对鸡胚发育与转基因表达效率的影响

背主动脉注射是生产转基因鸡的经典方法,该方法不需换壳培养,但壳内注射技术难度大,并且无法实时观察后期胚胎发育情况.本实验对背主动脉注射法进行了改进,将增强型绿色荧光蛋白(EGFP)腺相关病毒(Adeno-associated Virus,AAV)壳外注射至150枚HH 14～16期(Hamburger-Hamilton...     

鸡肉、鸡蛋中4种酰胺醇类药物残留的液相色谱-三重四级杆串联质谱(UPLC-MS/MS)分析方法建立

建立了鸡肉、鸡蛋中4种酰胺醇类药物(氯霉素CAP、氟苯尼考FF、甲砜霉素TAP、氟苯尼考胺FFA)残留的超高效液相色谱-三重四级杆串联质谱(UPLC-MS/MS)快速分析方法。样品用80%的乙腈震荡提取,经过PRiME HLB固相萃取柱直接净化,在40℃下氮吹浓缩,最后用10%乙腈复溶。以0.01%甲酸水-0.01%甲酸乙腈溶液作为流动相进行梯度洗脱,采用多反应监测(MRM)模式进行测定,内标法定量。4种酰胺醇类药物在0.5~20 ng/mL的浓度范围内呈现良好的线性关系,R₂^在0.9982~ 0.9988范围内。添加量为0.5、1、5μg/kg时,鸡肉中4种酰胺醇类药物回收率为89.6%~104.2%,鸡蛋中4种酰胺醇类药物回收率为85.9%~105.5%。通过回收率和精密度试验得出该方法具有较好的准确度和重复性。通过试验得出4种酰胺醇类药物检出限为0.05~0.1 μg/kg,定量限为0.2~0.5 μg/kg,本法操作简便、灵敏,准确,适合大批量鸡肉、鸡蛋样品中4种酰胺醇类药物的检测。     

冻融循环作用对黑土团聚体破碎机制的影响

为探究冻融循环作用对黑土团聚体抵抗不同破坏作用能力的影响,以黑龙江省典型黑土耕作层土壤为研究对象,通过LB法的3种不同破碎处理,分析冻融循环次数、初始含水量对不同初始粒级土壤团聚体稳定性的作用机制.结果表明:冻融循环作用对1～2,2～3,3～5 mm不同粒级团聚体稳定性有显著影响(P<0.05),其稳定性均呈现为湿润振...     

Campylobacter spp. prevalence and fluoroquinolone resistance in chicken layer farms

Chicken is a major source of human campylobacteriosis. Chicken meat originates not only from broilers but also from spent layers; however, few reports have documented the prevalence and antimicrobial resistance of Campylobacter spp. in layers in Japan. Therefore, we investigated the prevalence and antimicrobial susceptibility of Campylobacter spp. in 47 layer farms in Japan. Fecal samples were collected from the youngest and oldest flocks on the farm, and Campylobacter spp. was isolated from 46/47 (97.9%) farms. Among the C. jejuni isolates, the resistance rates to ampicillin, tetracycline, and ciprofloxacin were 29.6%, 22.2%, and 19.8%, respectively. The ciprofloxacin resistance rate (7.3%) in C. jejuni isolated from old flocks was significantly (P<0.01) lower than that in young flocks (32.5%).     

黑土坡耕地土壤流失形态分析——以一次降雨为例

以东北黑土区典型漫岗坡耕地为研究对象,测定次降雨条件下整个集水盆地出口处的径流体积及其含沙量,研究侵蚀泥沙的粒径分布特征、碳氮富集度以及可溶性养分的流失状况。结果表明,研究区只有在强降雨的情况下才会在集水盆地尺度上发生水土流失现象。20.5 mm降雨条件下(2006年8月1日)径流泥沙含量为1.0～2.5 g/L,泥沙C、N富集系数分别为2.10和3.31。径流液中DOC的浓度介于2.47～3.93 mg/L之间,TN浓度介于1.61～3.28 mg/L之间,径流携带养分量在整个养分流失过程中是不可忽视的流失途径。侵蚀泥沙(未加分散剂)的团聚体组成和原土壤有很大差异,径流泥沙的流失主要是粒径为0.053 mm以下的团聚体,尤其是0.002～0.02 mm的粉粒团聚体为主。     

Response of black, cranberry, kidney, and white bean to linuron

Dry bean producers in Ontario, Canada, have few herbicide options available for annual broad-leaved weed management and there is little information on the tolerance of dry bean to linuron. The tolerance of black, cranberry, kidney, and white bean to the pre-emergence (PRE) application of linuron at the rates of 0, 500, 1000, 1500, 2000, and 2500 g ai ha⁻¹ was evaluated in field studies conducted in 2005 and 2006 at Exeter and in 2006 at Ridgetown, Ontario. The four market classes differed in their response to linuron. Cranberry and kidney bean were more tolerant to the PRE application of linuron than black and white bean. Linuron applied PRE caused as much as 12% injury in cranberry and kidney bean, 47% injury in black bean, and 56% injury in white bean. Linuron applied PRE at 500–2500 g ai ha⁻¹ had no effect on the height of cranberry and kidney bean but decreased the height by 7, 8, and 15% in black bean and by 10, 13, and 23% in white bean at 1500, 2000, and 2500 g ai ha⁻¹, respectively. Linuron applied PRE at the rates evaluated did not cause any adverse affect on the yield of cranberry, kidney, and white bean but black bean yield was reduced by 16% at 2500 g ai ha⁻¹. Based on these results, there is not an adequate margin of crop safety for the PRE application of linuron in black and white bean at rates >1000 g ai ha⁻¹. However, there is a potential for the use of linuron PRE for weed management in cranberry and kidney bean at the rates evaluated.     

黄土高原子午岭油松林管理方式对黑碳和颗粒有机碳积累的影响

对黄土高原子午岭油松林不同管理方式下土壤的黑碳(BC)、有机碳(POC)和活性有机碳(LOC)的空间分布和积累进行了研究.结果表明,各种管理方式的油松林其POC、LOC和BC由表层至下层均呈显著的降低规律性.各种管理方式油松林0～10cm土层以BC>POC>LOC,10～20 cm土层中,天然油松林和粗放管理型油松林B...     

荔枝害虫群落结构及其动态研究

以栽培品种ＮＣ８９为对照,通过室内饲养和组织切片,系统研究了转双基因抗虫烟草对烟夜蛾和小地老虎幼虫的抗性表现。结果表明,转双基因抗虫烟草对烟夜蛾幼虫具有稳定的杀虫作用,取食后２－３ｄ死亡,死亡率达１００％,不同龄期间表现一致;对小地老虎幼虫个有一定的杀虫作用,其抗性随龄期的增加而减弱,１龄死亡率为４８％,２龄为２８％,３龄以后死亡率为０,但对各龄幼虫的生长发育均具有明显的抑制作用。     

马铃薯黑痣病生防菌的筛选及防治效果

由立枯丝核菌(Rhizoctonia solani)引起的马铃薯黑痣病由于常年连作和马铃薯种植规模扩大,病害发生越来越严重[1,2].目前马铃薯黑痣病的防治主要依靠农药的施用[3,4],但化学药剂的频繁使用会导致抗药性的产生、同时带来农药残留和环境污染等问题[5].从棉花根际土壤分离得到的多粘类芽胞杆菌Sx3可产生杀镰...     

旱地小麦黑膜全覆盖穴播栽培的效应与模式研究

本研究通过对黑膜、无色膜、垄作、平作、沟播等因素进行组合,探讨了旱地冬小麦地膜全覆盖穴播不同栽培模式的膜下茎和杂草发生规律、土壤温度和水分变化动态及增产增收效果。结果表明,小麦采用黑膜覆盖,自动出苗率比无色膜覆盖平均提高63.73%,膜下茎密度和鲜重分别降低74%以上和98%左右,杂草盛发期的密度和鲜重分别比无色膜覆盖降低62.03%和96.70%,比露地栽培降低70.00%和92.93%。黑膜覆盖小麦全生育期0~25 cm土壤积温比无色膜覆盖降低108.8℃,比露地降低62.9℃,但在播种至拔节阶段,比露地增加72.8℃,拔节至成熟比露地降低135.7℃。水分利用效率黑膜覆盖比无色膜覆盖提高4.48%,比露地提高45.75%。黑膜覆盖比无色膜增产3.05%,比露地增产47.81%。3种起垄方式中,垄作比平作小麦自动出苗率平均提高44.00%,沟播则降低23.80%;膜下茎密度垄作降低35.59%以上,沟播增加25.64%以上;膜下茎鲜重垄作降低30.62%以上,沟播增加12.09%以上。垄作提高土壤积温90.5℃,沟播降低23.5℃;垄作增产3.24%,沟播增产4.90%。以黑色全膜垄作穴播为最佳模式,较全膜覆土穴播自动出苗率平均提高146.93%,膜下茎密度降低98.74%以上,杂草鲜重降低99.90%以上,全生育期增加土壤积温52.0℃,水分利用效率提高10.75%,增产8.68%,节本4 020元·hm~(-2),增加纯收益5 422元·hm~(-2)。且膜面覆土量减少75%,易于清除残膜。其中通用垄沟半微垄模式具有宽窄行距的特点,较微垄模式增产3.89%,增收11.33%,并且适宜机械化作业。