Induction effects of host plants on insecticide susceptibility and detoxification enzymes of Bemisia tabaci (Hemiptera: Aleyrodidae)

BACKGROUND: The polyphagous B‐biotype Bemisia tabaci (Gennadius) has developed a high resistance to commonly used insecticides in China. To illustrate the induced changes by host plant, bioassay and biochemical research on five different host populations were investigated. RESULTS: Except for bifenthrin, all tested insecticides showed lower toxicity to the B. tabaci poinsettia population compared with other host populations. Moreover, four insecticides, the exceptions being abamectin and fipronil, showed highest toxicity towards the tomato population. The LC₅₀ values of the poinsettia population, particularly towards acetamiprid, were 14.8‐, 10.3‐ and 7.29‐fold higher than those of tomato, cucumber and cabbage respectively. The CarE activities of B. tabaci cabbage and cucumber populations were all significantly higher than those of poinsettia, cotton and tomato populations. The ratio of the cabbage population was 1.97‐, 1.79‐ and 1.30‐fold higher than that of poinsettia, cotton and tomato respectively. The frequency profiles for this activity also have obvious differences. The GST and P450 activities of the cucumber population were the lowest in the five host populations. CONCLUSION: Long‐term induction of host plants for B‐biotype B. tabaci could influence their susceptibilities to several insecticides. Rational selection and usage of insecticides for particular hosts will be helpful for resistance management and control of this species. Copyright © 2010 Society of Chemical Industry     

不同土壤环境因素对微塑料吸附四环素的影响

为探究不同土壤环境因素对于微塑料吸附抗生素的影响,选用三种常见的微塑料:聚乙烯(PE)、聚苯乙烯(PS)和聚酰胺(PA),以四环素(TC)代表抗生素,通过批平衡试验来研究微塑料对TC的吸附行为和机理。研究发现,3种微塑料对TC的等温吸附方程均可用Langmuir方程进行拟合,其吸附能力为PEPSPA,最大吸附量分别为0.154、0.086、0.075 mg·g~(-1)。在中性条件下PE对TC的吸附量达到最大,pH对PA吸附TC影响较小,而PS在酸性条件下对TC的吸附量最大,且随着pH增加吸附量逐渐降低。不同浓度的Ca~(2+)和Mg~(2+)会影响微塑料对TC的吸附,且随着浓度的增加,吸附量逐渐降低。富里酸的存在抑制了TC在PE上的吸附,但低浓度的富里酸(1 mg·L~(-1))会促进PA和PS吸附TC。结果表明,不同微塑料对TC的吸附存在显著差异,且不同土壤环境因素明显影响了微塑料对TC的吸附行为,该结果为进一步研究和评估微塑料在土壤环境中的吸附行为奠定了基础。     

利用体外产气法研究戊酸对山羊瘤胃发酵的影响

应用体外产气法模拟瘤胃发酵,通过测定24 h体外累计产气量、细菌氮含量和中性洗涤纤维(NDF)的降解率,评价戊酸的不同添加水平对山羊瘤胃发酵的影响.试验采用单因子设计,戊酸的添加水平分别为0%、0.3%、0.6%、0.9%、1.2%,每个水平4个重复.结果表明与对照组相比,添加0.6%的戊酸组能显著提高24 h累计产气量(P＜0.05)和极显著提高细菌氮含量(P＜0.01);在添加戊酸水平为0%～0.3%时,NDF降解率有提高的趋势,但是差异不显著(P＞0.05),在0.3%～1.2%时,其NDF降解率显著下降(P＜0.05).建议日粮中戊酸的适宜添加水平为0.6%.     

Genetic components of heat stress in finishing pigs: development of a heat load function

The objective of this study was to quantify the effect of heat stress during the life of a pig on its final weight, as a first step toward a genetic evaluation for heat tolerance. Data included carcass weights of 23,556 crossbred pigs [Duroc x (Landrace x Large White)] raised on 2 farms in North Carolina and slaughtered from May 2005 through December 2006. Weather data were available from a nearby weather station. Lifetime of a pig was assumed to be partitioned into 2 periods. During an initial period, the effect of heat stress was assumed to be negligible or compensated for later. During the second period ending in slaughtering, the ADG was assumed to be affected linearly by heat load. Weekly heat load was calculated as degrees of average temperature-humidity index in excess of a threshold (18 degrees C). The total heat load (H) was the sum of weekly heat loads during the second period. During the months of January to May H was 0; H reached a peak in September. The final BW during the peak of heat stress decreased about 6 kg compared with BW during months of non-heat stress. Weekly and monthly averages of carcass weight generally moved similarly to H. However, there were large fluctuations unrelated to H; the fluctuations were different on the 2 farms. The model included the effects of farm-year of slaughter, sex, age at slaughter, and H, where age at slaughter and H were linear regressions. In analyses, the threshold was varied from 16 to 20 degrees C, and the second period was varied from 8 to 16 wk. The greatest R(2) (10.4%) was at the threshold of temperature-humidity index = 18 degrees C for a period of 10 wk. Varying the threshold and the length of time reduced R(2) less than 1%. Least squares means of year-month and year-week of carcass weight were calculated using a model with the fixed effects farm-year-month or farm-year-week of slaughter, sex, and age at slaughter (linear covariate), and the random effect of birth litter. Changes in BW of finisher pigs due to heat stress can be quantified by H during the last 10 wk of the life of the pig.     

Early Pregnancy Diagnosis by Serum Progesterone and Ultrasound in Sheep Carrying Somatic Cell Nuclear Transfer-Derived Pregnancies

Early pregnancy diagnosis and monitoring play an important role following embryo transfer in sheep. The aims of the current study were to investigate (i) the pattern of serum progesterone profiles in sheep carrying somatic cell nuclear transfer (SCNT)‐derived (clone) pregnancies, and (ii) the frequency of pregnancy loss during development following SCNT embryo transfer. Sheep SCNT embryos were made using standard nuclear transfer techniques. Day 7 embryos were surgically transferred to oestrus‐synchronized recipients (n = 27). As a control, normal fertile ewes (n = 12) were bred by natural breeding. Serum was collected from all the ewes on the day of estrus (day 0 sample), 7 days post‐estrus (day 7 sample) and 19 days post‐estrus (day 19 sample) and every 10 days thereafter until lambing or pregnancy loss occurred. Serum progesterone (P4) was assessed using enzyme immunoassay. Pregnancy was confirmed by ultrasound scanning on day 35 of pregnancy followed by subsequent scanning every 10 days. In control ewes, pregnancy rate on day 35 was 83.3% (10/12), whereas in the ewes that received SCNT embryos, it was 22.2% (6/27; p < 0.05). The day 45 pregnancy rate in the control ewes was 83.3%, whereas in the SCNT embryo recipients it was 11.0% (p < 0.05). Hormone analysis revealed that SCNT embryo recipients exhibited a significantly lower P4 profiles at different time points in pregnancy compared to controls (p < 0.05). This study highlights the use of serum progesterone in combination with ultrasound for the investigation of embryo loss and crucial times during development of normal and SCNT embryos in sheep. Further, the serum P4 levels directly reflect the degree of placental development in these two groups.     

内蒙古自治区畜禽养殖粪污资源化利用的对策与建议

畜牧产业是内蒙古自治区的支柱产业之一,随着畜牧业快速发展,畜禽粪污产量持续增加,导致粪污污染日益严重,因此,畜禽养殖粪污资源化利用显得尤为迫切和重要。调研了内蒙古自治区11个旗（县、区）、95户大中型规模化养殖企业,并通过文献查阅及专家咨询等方式调研了3 700户规模化养殖企业,从内蒙古自治区畜禽粪污的基本特征、畜禽粪污资源化利用主要特征和对策与建议方面分析了自治区畜禽养殖粪污及资源化利用的情况。     

不同补播模式对荒漠草原土壤团聚体稳定性的影响

针对宁夏荒漠草原退化生态系统,采用地表深翻处理后补播蒙古冰草+沙生冰草+牛枝子、沙生冰草+牛枝子、蒙古冰草+牛枝子3种模式进行改良,以未补播草地为对照,通过团聚体粒径组成、平均重量直径、几何平均直径、破坏率等指标,研究不同补播模式对宁夏荒漠草原土壤团聚体稳定性的影响。结果表明,0~40cm土层,各补播草地机械稳定性及水稳性团聚体均以<0.25mm微团聚体为主,且随土层加深<0.25mm微团聚体含量逐渐减少,土壤结构趋于稳定;0~20cm浅层土壤,蒙古冰草+沙生冰草+牛枝子补播草地的>0.25mm机械稳定性团聚体含量显著高于未补播草地(P<0.05),不同处理草地之间>0.25mm水稳性团聚体含量、平均重量直径、几何平均直径及破坏率差异不显著。综上,深翻后补播蒙古冰草+沙生冰草+牛枝子可改善荒漠草原0~20cm浅层土壤机械团聚体稳定性。     

miR-18a通过靶向结合CTGF调控猪颗粒细胞凋亡

为探究miR-18a对猪卵巢颗粒细胞凋亡的调控作用,利用生物信息学分析、荧光素酶活性检测和体外培养颗粒细胞试验验证miR-18a对CTGF的靶向作用及其在猪颗粒细胞中对CTGF基因表达的影响,并通过流式细胞技术检测其对猪卵巢颗粒细胞凋亡的调控作用。生物信息学分析结果表明,CTGF是miR-18a的潜在靶基因,荧光素酶活性检测进一步验证了miR-18a与CTGF的结合。在培养的颗粒细胞中转染miR-18a模拟物后,qRT-PCR和Western blot结果显示CTGF的mRNA和蛋白水平均显著降低,流式细胞技术检测表明miR-18a显著促进颗粒细胞的凋亡。而转染miR-18a抑制剂后,猪颗粒细胞的凋亡率显著降低,共转染miR-18a抑制剂和CTGF的干扰RNA后,颗粒细胞的凋亡率呈现回升。试验结果表明miR-18a通过靶向结合CTGF基因调控猪颗粒细胞的凋亡。     

南疆杏李园梨小食心虫成虫消长动态及迷向防治效果

为明确南疆新兴特色水果杏李上梨小食心虫Grapholita molesta（Busck）的发生规律和迷向防治效果,于2021—2022年在新疆维吾尔自治区阿克苏地区杏李园采用性诱剂诱集法监测梨小食心虫种群动态,评估性信息素迷向丝对梨小食心虫的防治效果。结果表明,梨小食心虫在阿克苏杏李园1年发生4代,其中越冬代羽化高峰期在4月上中旬,第1代羽化高峰期在5月下旬至6月上旬,第2代羽化高峰期在7月上旬,第3代羽化高峰期在8月上中旬,存在世代重叠现象。2022年农户常规防治区内梨小食心虫的蛀果率为2.46%,性信息素迷向防治区内蛀果率为0.06%; 2021年和2022年使用性信息素迷向丝对梨小食心虫的蛀梢减退率为98.13%和88.65%,2022年的蛀果减退率为98.40%;对不同世代梨小食心虫的雄成虫迷向率在2021年为92.87%~100.00%,雌、雄成虫虫口减退率在2022年为58.75%~81.37%。表明采用梨小食心虫性信息素迷向丝为主的综合防控技术,可有效控制南疆杏李园梨小食心虫的发生与为害。     

Effect of human tissue factor pathway inhibitor gene transfection in vein grafts on thrombus formation and early patency rate

AIM: To reduce thrombus formation after coronary artery bypass graft,we investigated the antithrombotic effect of human tissue factor pathway inhibitor (TFPI) gene delivery on vein grafts. METHODS: The eukaryotic expressed plasmid vector pCMV-(Kozak)TFPI was constructed. Through pressurizing infusion,vein endotheliocytes were transfected with cationic liposome containing the plasmid vector pCMV-(Kozak)TFPI. After operation, vein grafts were harvested at third day for immunohistochemical, RT-PCR and Western blotting analysis of exogenous gene expression and for observation of thrombus formation by pathological method and scanning electron microscopy. At 30th days, the patency rate was recorded by vessel Doppler ultrasonography. RESULTS: Human TFPI mRNA and protein were detected in TFPI gene transferred vein grafts. Thrombosis was found in 8 animals of empty plasmid control group and in 7 animals of empty control group, but in only 1 of the TFPI group (P<0.05). Thirty days after operation, 5 vein grafts were occluded in both empty plasmid control group and empty control group, but none of vein grafts were occluded in TFPI group (P<0.05). The endothelial surfaces of the vein grafts in both control groups were covered with aggregated erythrocytes and platelets, but not in TFPI group. CONCLUSION: Human tissue factor pathway inhibitor gene transfection reduces thrombus formation and improves early patency rate in vein grafts.