Phosphine resistance, respiration rate and fitness consequences in stored-product insects

Resistance to fumigants has been frequently reported in insect pests of stored products and is one of the obstacles in controlling these pests. The authors studied phosphine resistance and its physiological basis in adult insects of 12 populations of Tribolium castaneum (Herbst) (Tenebrionidae), ten populations of Rhyzopertha dominica (F.) (Bostrichidae) and eight populations of Oryzaephilus surinamensis L. (Silvanidae) from Brazil, and the possible existence of fitness costs associated with phosphine resistance in the absence of this fumigant. The bioassays for the detection of phosphine resistance followed the FAO standard method. The production of carbon dioxide and the instantaneous rate of population increase (r(i)) of each population of each species were correlated with their resistance ratios at the LC(50). The resistance ratio at LC(50) in T. castaneum ranged from 1.0- to 186.2-fold, in R. dominica from 2.0- to 71.0-fold and in O. surinamensis from 1.9- to 32.2-fold. Ten populations of T. castaneum, nine populations of R. dominica and seven populations of O. surinamensis were resistant to phosphine. In all three species there was significant association (P < 0.05) between respiration rate and phosphine resistance. The populations with lower carbon dioxide production showed a higher resistance ratio, suggesting that the lower respiration rate is the physiological basis of phosphine resistance by reducing the fumigant uptake in the resistant insects. Conversely, populations with higher r(i) showed lower resistance ratios, which could indicate a lower rate of reproduction of the resistant populations compared with susceptible populations. Thus, management strategies based on the interruption of phosphine fumigation may result in reestablishment of susceptibility, and shows good potential for more effective management of phosphine-resistant populations.     

Propanil and swep inhibit 4-coumarate:CoA ligase activity in vitro

4-Coumarate:CoA ligase (4CL, EC 6.2.1.12) in the phenylpropanoid pathway in plants has attracted interest as a novel target for developing effective plant growth inhibitors (PGIs). In a previous study in which the 4CL inhibitory activity of 28 existing herbicides was investigated using an optimized in vitro screening assay, 4CL activity was found to be strongly inhibited by propanil and swep at 100 microM. Here, further experimental evidence is provided to substantiate the previous result. Using 4-coumaric acid as substrate, tobacco 4CL activity was inhibited by propanil or swep in a concentration-dependent manner, with 50% inhibition concentrations (I(50)) of 39.6 and 6 microM respectively. These herbicides also exhibited uncompetitive inhibition towards 4-coumaric acid. Furthermore, 4CLs from several plant species were inhibited by the herbicides within a range from 1 to 50 microM. It is proposed that these herbicides have another site of action as a result of the inhibition of 4CL in the phenylpropanoid pathway, and this enzyme represents a new target site for the development of PGI.     

马氏珠母贝IGF2BP1基因的鉴定及对矿化相关基因表达的影响

胰岛素样生长因子2结合蛋白( IGF2BPs)是一种重要的RNA代谢调控因子,涉及多个不同的生物学过程。本研究鉴定了一个马氏珠母贝IGF2BP1基因,命名为PfIGF2BP1-1,该基因cDNA全长为7348 bp,ORF长 1818 bp,编码605个氨基酸。多序列比对和系统进化分析表明,PfIGF2BP1-1有2个RRM结构域和4个KH结构域,与其他物种来源的IGF2BPs同源。实时荧光定量PCR结果显示,PfIGF2BP1-1 在马氏珠母贝的8个组织中均有表达,在肌肉组织表达最高,其次为足和外套膜组织。利用pET-32a 原核表达载体构建了含有PfIGF2BP1-1成熟多肽区的重组质粒并成功表达蛋白。在IPTG浓度为0.5 mmol/L,37 ℃培养8 h的条件下诱导表达PfIGF2BP1-1蛋白最佳。PfIGF2BP1-1蛋白刺激马氏珠母贝外套膜原代细胞,引起壳基质蛋白基因Accbp、MSI7、Nacrein的表达水平显著上升(p < 0.05),表明PfIGF2BP1-1蛋白可诱导壳矿化相关基因的表达参与马氏珠母贝的生物矿化过程。     

嗜水气单胞菌ompA、flaA基因重组干酪乳杆菌对鲤生长及免疫效果分析

为构建嗜水气单胞菌ompA和flaA基因重组干酪乳杆菌并分别检测其表达产物对鲤生长及免疫效果的影响,实验将目的基因克隆至乳酸菌穿梭表达质粒pPG612中,并电转至干酪乳杆菌中,经诱导后包被饲料对鲤进行饲养56 d,称重并采集血清及组织,分析生长指标及免疫指标变化。在56 d饲养免疫结束后结果显示,生长指标显示重组干酪乳杆菌组与对照组无显著差异,表明重组干酪乳杆菌对生长无影响;免疫效果分析显示,血清中IgM表达水平显著上升。血清中AKP、LZM、SOD、CAT、C3和C4也均显著升高。荧光定量PCR检测发现,免疫后肝脏、脾脏、头肾及肠组织中的细胞免疫因子基因IL-1β、IL-8、TNF-α、 NF-κB、 TLR5及MYD88的表达水平有不同程度的显著提升;其中TLR5及MYD88表达量在Lc-mcs-flaA组高于Lc-mcs-ompA组。攻毒后Lc-mcs-ompA与Lc-mcs-flaA组免疫保护率分别为59%与54%,显著高于对照组。研究表明,本实验构建的重组干酪乳杆菌Lc-mcs-ompA与Lc-mcs-flaA免疫鲤能刺激机体产生免疫应答反应,进而提高自身存活率,为预防鱼类嗜...     

Dietary plant protein utilization in Atlantic cod, Gadus morhua L.

The present trials aimed to investigate the effects of replacing fish meal with plant proteins in diets for cod, using a regression design where fish meal constituted the control. The plant protein diets were formulated to meet the amino acid requirements according to NRC (1993) and contained corn gluten meal, soybean meal, a mixture of these, or a mixture of wheat gluten meal and soybean concentrate. The plant protein fraction constituted up to 440 g kg⁻¹ of the extruded diet. Two feeding experiments were conducted, one at high (11 °C) and one at low (6.5 °C) temperature. High growth and feed utilization were obtained in all diet groups at both temperatures. However, only in Exp.1 (11 °C), growth and feed utilization were linearly reduced by increases in dietary soybean and corn gluten meal, while no such effect was detected in Exp.2 (6.5 °C). Reductions in protein retention were seen at both temperatures with use of all evaluated plant protein sources. Due to large amounts of plant protein ingredients in diet, differences in diet amino acid composition were seen. These were partly reflected in the muscle free amino acid pool. Dietary plant ingredients did not affect whole body, liver or muscle proximate compositions, or liver indices. In both experiments, blood parameters were within the range of earlier reported normal values and indicated, together with low mortality, good fish health status. The results show that there is high potential to use protein‐rich plant ingredients in diets for Atlantic cod.     

Effect of bovine colostrum intake on growth,reproductive parameters and survival in red kids

The aim of this study is to evaluate the efficacy of frozen Azawak colostrum supplementation on body weight (BW), average daily gain (ADG), reproductive parameters (mean age at first parturition, fertility, fecundity, prolificacy) and mortality rate among red kids. The study was conducted at the goat farm secondary centre of Maradi in Niger from September 2010 to September 2011. The control animals (n = 20) were left with their mother, while the treatment animals (n = 20) received in addition 50 ml/animal/day of bovine colostrum at birth and 15 ml/animal/day from d2 to d15. Weight was measured weekly from birth to d365. Mortalities were also recorded over the same period. For reproductive parameters, observations began at weaning (d197). Growth rate was higher (p < 0.001) in supplemented animal, and the treatment effects on ADG were observed up to 150 day after the end of supplementation. A similar long‐lasting trend was also observed in relation to the mortality rate (25% for ColG vs. 55% for ConG; p = 0.05). The age at first kidding tended to be lower in the treated group (13.8 ± 0.7 vs. 14.1 ± 0.8 month; p < 0.1). In conclusion, mild bovine colostrum supplementation induces a long‐lasting positive impact on growth rate and to a lower extent on reproduction parameters and survival rate.     

Responses to betaine and inorganic sulphur of sheep in growth performance and fibre growth

Sulphur‐containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous.     

海滨锦葵块根粉和酶制剂对断奶仔猪生长和免疫的影响

以断奶仔猪为试验对象,探讨海滨锦葵块根粉和酶制剂对断奶仔猪生长和免疫的影响。64头28日龄断奶仔猪随机分为4组,对照组饲喂基础日粮,试验I、Ⅱ、Ⅲ组分别饲喂基础日粮添加0．02％复合酶制剂、0．50％和1．00％海滨锦葵块根粉。试验期28d。结果表明,酶制荆和海滨锦葵块根粉对断奶仔猪的日采食量和日增重有提高趋势,但差异不显著（P〉0．05）;与对照组相比,酶制剂和海滨锦葵块根粉对断奶仔猪血清中溶菌酶活性无显著影响（P〉0．05）;有降低血清中TNF-Ⅱ含量的趋势,但差异不显著（P〉0．05）;与对照组相比,酶制剂可以显著降低IL-6含量（P〈0．05）,海滨锦葵块根粉也降低了IL6含量,但差异不显著（P〉0．05）;与对照组相比,酶制剂组、0．50％和1．00％的海滨锦葵块根粉组的猪瘟疫苗抗体效价分别提高了15．27％（P〉0．05）、18．18％（P〉0．05）和5I．64％（P〈0．05）。结果提示,酶制剂与海滨锦葵块根粉对断奶仔猪生长性能有提高趋势,同时也可以提高断奶仔猪的机体免疫力。     

水通道蛋白9的研究进展

水通道蛋白9在机体内许多器官组织中表达,它对水、尿素、甘油等分子均有通透性,其基因结构、染色体定位、蛋白质结构、组织分布和生理功能也已得到了较为深入的研究。本文对水通道蛋白9基因的结构特点、分子结构、分布和生理功能作一综述,以期为相关疾病诊治和生产实践提供理论依据。     

蜀宣花牛体型外貌、线性评定及生理指标测定

[目的]为了充分了解牛群的体型外貌及生理指标情况,我们对牛群体型外貌进行了评定、同时对牛群的毛色、肤色、踢、角及生理指标进行了调查研究。[方法]通过对牛群生理指标测定、体型外貌评定及毛色、肤色、踢、角颜色和形状分析。[结果]表明:蜀宣花牛肉用指数公母牛分别为5.3769和4.0725,低于国外专门化肉牛品种,但也明显高于国内几个比较有名的地方牛品种,由此说明,蜀宣花牛的肉用指数界于专用型肉牛和肉役兼用型牛之间。毛色以黄白花和红白花为主,占90.16%;皮肤颜色以纯粉色和粉色有斑点的为主,占96.92%;蹄质颜色以纯蜡黄色为主,占86.28%;角型以照阳角为主,占93.94%。成年母牛的生理指标分别为:体温平均38.38℃、心跳74.56次/min、呼吸18.74次/min和瘤胃蠕动2.84次/2min;体型外貌线性评定分析表明,蜀宣花牛母牛的14个性状中,除后房宽度、尻角度和乳房底部3个性状平均分略低于75分,强壮度、后房高度、乳头位置和乳静脉4个性状的平均分高于80分外,其余7个性状的平均分都在75~80分之间。[结论]从乳用性能的角度看,牛群的平均体型尚处在较理想型和理想型之间,还有待进一步选育提高。