Behavioral and electrophysiological response of sugarcane aphid and imported fire ant to 2,4,6-trimethylpyridine,an alkaloid from the pink-spotted lady beetle

Many predatory coccinellids conflict with hemipteran tending ants, because they both use hemipterans as resources. Lady beetles are important in the ecology of ants and their reciprocal relationship with hemipterans. Volatiles released by lady beetles have diverse biological significance in intraspecific communication, attraction, and aggregation. However, whether the semiochemicals from lady beetles influence the sympatric members, such as aphids and ants, is still obscure. Sugarcane aphids Melanaphis sacchari was closely associated with honeydew collecting ants and coccinellid predators. Herein, we investigated the behavioral and electrophysiological responses of M. sacchari and their attending red imported fire ants, Solenopsis invicta, to an alkaloid, 2,4,6-trimethylpyridine (TMP) from the pink-spotted lady beetle Coleomegilla maculata. The response of C. maculata to this alkaloid was also evaluated. The results showed that TMP elicited significant electroantennogram (EAG) responses in M. sacchari, S. invicta, and C. maculata. In addition, it triggered significant preference and aggregation in both C. maculata males and females at 100 μg/μL, while induced a strong avoidance in M. sacchari. It significantly decreased the digging and residing preference of S. invicta workers at high concentration, but showed certain attractiveness to workers at a lower concentration. Moreover, TMP inhibited aphid-tending efficiency of S. invicta thereby curbing the benefits to M. sacchari. The findings provide important evidence that TMP is a pheromone in C. maculata and a semiochemical to both S. invicta and M. sacchari. It may affect the mutualistic interactions between S. invicta and M. sacchari by mediating the behaviors of both species.

     

利用休眠控制河蟹性腺早熟的养殖试验

该项试验是针对近年来在河蟹养殖中幼蟹（扣蟹）性腺早熟提出的研究课题。根据顾景龄等“河蟹生长规律及性腺早熟控制的研究”证明：幼蟹性腺早熟的主要原因是６月至７月底期间，幼蟹蜕壳过频，生长过快所致、为控制幼蟹的性腺早熟，我们经过多年的试验研究，探索出利用“休眠”控制其早熟的养殖方法，并于１９９３年６月至９月３０日，在天津宁河县试验林场６． ６７ｈｍ２的河蟹精养池塘进行了生产性试验，在 ６月 １０日至 ８月 ５日期间，停止投饵、换水，使幼蟹进入休眠状态，８月５日以后，驯化投喂人工配合饵料，并严格控制水质，到９月３０日，幼蟹平均个体重达 ２３．９ ｇ，与对照组平均体重２５． ７ ｇ相近似，试验组早熟率不超过 ４％，而对照池（３．３３ ｈｍ２）几乎全部早熟。因此可以说这是一种控制幼蟹早熟简单而有效的方法。     

米糠谷蛋白与β-环状糊精热聚集对乳化性质和结构特性的影响

为提高米糠谷蛋白功能性质,本研究对米糠谷蛋白与β-环状糊精进行复合热处理（温度60、70、80、90、99℃,时间40、80、120、160、200 min）,分析复合聚集体的浊度、接枝度、乳化性质及结构特性等,探究米糠谷蛋白与β-环状糊精复合热聚集行为。结果表明,米糠谷蛋白与β-环状糊精在90℃条件下加热复合160 min时,复合聚集体乳化活性指数达到最大,与天然米糠谷蛋白相比提高了2.39倍;在80℃条件下加热复合200 min时,复合聚集体乳化稳定性指数最大,与天然米糠谷蛋白相比提高了2.39倍。复合物在80℃条件下受热后,米糠谷蛋白与β-环状糊精结合生成较大颗粒的聚集体;复合物中米糠谷蛋白肽链结构打开,游离巯基含量增加,二硫键断开,疏水基团暴露,β-折叠向α-螺旋和β-转角转化,以共价键的形式形成分子间氢键,使得复合聚集体分子更好地结合到油水的界面,复合聚集体乳化活性和稳定性显著提高（P<0.05）。本研究结果为后续米糠蛋白质功能性质的改善及米糠蛋白质的深加工提供了理论依据。     

Changes in CH<Subscript>4</Subscript> production during different stages of litter decomposition under inundation and N addition

Purpose

Our aim was to examine linkages between mass loss, chemical transformation and CH₄ production during decomposition of leaf litters submerged under water. We hypothesised that (i) labile leaf litters would fuel a rapid, high rate of methane (CH₄) production and that recalcitrant litters would fuel long-lasting but lower emissions, (ii) leaf litters experiencing a greater alteration to chemical properties would stimulate increased CH₄ production and (iii) nitrogen (N) addition would increase CH₄ emissions.

Materials and methods

Litters from six plant species were collected from a riparian ecosystem adjacent to Wyaralong Dam, located in Queensland, Australia, i.e., Lophostemon confertus, Cynodon dactylon, Heteropogon contortus, Chamaecrista rotundifolia, Chrysocephalum apiculatum and Imperata cylindrica. We evaluated the rate of mass loss and CH₄ emissions for 122 days of incubation in inundated microcosms with and without N addition. We quantified the chemical changes in the decomposing litters with ¹³ C-cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectrum.

Results and discussion

The inundation treatment of plant litters significantly affected decomposition rates. All litters decomposed in either inundated or aerobic microcosms were quite distinct with regard to the NMR spectra of their initial litters. N addition altered the NMR spectra under both inundation and aerobic conditions. The N treatment only marginally influenced the decomposition rates of I. cylindrica and C. apiculatum litters. The diurnal patterns of CH₄ production in the H. contortus, C. rotundifolia and C. apiculatum litters under inundation incubation could be expressed as one-humped curves, with the peak value dependent on litter species and N treatment. N addition stimulated CH₄ emission by C. rotundifolia and C. apiculatum litters and inhibited CH₄ emission from microcosms containing the litters of the three gramineous species, i.e., I. cylindrica, C. dactylon and H. contortus.

Conclusions

Our results provide evidence that labile leaf litters could fuel a rapid, high rate of CH₄ production and that recalcitrant litters fuelled a lower CH₄ emission. We did not find that leaf litters with altered chemical properties stimulated increased CH₄ production. We also found that N addition was able to increase CH₄ emissions, but this effect was dependent on the litter species.

     

新疆巴州幼年与成年牦牛瘤胃细菌区系多样性分析

为比较年龄对牦牛瘤胃细菌区系多样性的影响,以新疆巴州1岁幼年牦牛和4岁成年牦牛的瘤胃微生物总DNA为研究材料,利用16S rRNA基因序列分析技术对牦牛瘤胃细菌区系的操作归类单元(OTU)聚类、门和属水平上的物种丰度、Alpha多样性进行比较分析。结果表明,在门水平上,厚壁菌门(Firmicutes)相对丰度为66.96%~70.31%,拟杆菌门(Bacteroides)相对丰度为21.87%~24.11%,其他菌类所占比例极少。在属水平上,普雷沃菌属(Prevotella)在幼年牦牛瘤胃内相对丰度(4.69%)高于成年牦牛(2.68%);瘤胃球菌属(Ruminococcus)在幼年牦牛瘤胃内相对丰度(4.69%)比在成年牦牛瘤胃内(1.79%)高。幼年和成年牦牛的Chao1指数分别为783.50和544.00,Shannon指数分别为4.68和4.52。综上可知,在同一草地放牧饲养条件下,1岁和4岁巴州牦牛瘤胃细菌区系组成存在明显差异,幼年牦牛瘤胃消化吸收的功能正在转化建立的过程中,所以Chao1指数和Shannon指数高于成年牦牛,且瘤胃细菌物种丰度和多样性更高。本研究结果为该地区牦牛瘤胃微生物稳态及其营养调控研究提供了参考依据。     

基于卫气理论辨治周围神经病——中医脑病理论与临床实证研究(六)

卫气即起维护、保护或蔽护作用的正气。卫气出于脑,双向调控全身神机;卫气并脉,与营气耦合承制衡铨;卫气分阴阳,变化有序自稳调节。卫气与周围神经分布部位、神经传导方向、神经功能特点等有相关性。通过面神经炎、三叉神经痛、非霍奇金淋巴瘤胸腔引流术后肋间神经痛、酒精中毒性周围神经病4个医案,阐释周围神经病卫气内伐、卫气不足、卫气归并、卫气逆行的病机特征;坚持形神一体观,谨守病机,权衡和法,调畅气机,以通为用的临床思维。周围神经病辨治在于坚持辨证用药、气化用药、双向用药、对症用药,重视外治方法应用。     

Interactive effects of dietary leucine and isoleucine on growth,blood parameters,and amino acid profile of Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

A 60-day feeding trial was conducted to assess the interactions of dietary leucine (Leu) and isoleucine (Ile) on Japanese flounder. Fish of 2.69 ± 0.04 g were fed experimental diets containing two levels of Leu (2.58 and 5.08% of diet) combined with three levels of Ile (1.44, 2.21, and 4.44% of diet), respectively. After the feeding trial, growth, proximate composition, muscle total amino acid profile, blood parameters, mucus lysozyme activity, and stress tolerance to freshwater were measured. Statistically significant (P < 0.05) interactive effects of Leu and Ile were found on growth parameters (final body weight, body weight gain, and special growth rate) of Japanese flounder. Antagonism was discovered in high dietary Leu groups, while stimulatory effects were obtained for increased dietary Ile in low Leu groups. Interactive effects of these two branched-chain amino acids were also found on hepatosomatic index of test fish. In addition, crude lipid content of fish whole body was significantly altered by various diets, with antagonism observed in low dietary Leu groups. Interactive effects also existed in muscle amino acid profiles for low fish meal diets, but no interactive impacts were observed on blood parameters. Furthermore, lysozyme activities and freshwater stress were significantly affected by different diets. And antagonism was found on lysozyme activities in low Leu groups. Moreover, high Leu and high Ile levels of diet significantly altered freshwater stress tolerance of Japanese flounder. These findings suggested that dietary Leu and Ile can effect interactively, and fish fed with diets containing 2.58% Leu with 4.44% Ile and 5.08% Leu with 1.44% Ile showed better growth performance.     

哺乳期补饲开食料对牦牛犊牛生长性能、腹泻频率和发病频率的影响

本试验旨在探究哺乳期补饲开食料对牦牛犊牛生长性能、腹泻频率和发病频率的影响.选取1月龄、体重相近的20头牦牛犊牛,随机分为试验组和对照组,每组10个重复,每个重复1头牛.在第1～100天,试验组补饲开食料,对照组不补饲开食料;在第101～150天,试验组和对照组饲喂相同的饲粮.测定牦牛犊牛的采食量、体重和体尺,并计算腹...     

基于协方差分析对20～40 kg生长猪真可消化赖氨酸需要量研究

试验选用35头体重为20kg左右的杜×(长×大)三元杂交阉公猪,采用完全随机单因子试验设计,随机分为5个处理,单栏饲喂,自由采食,试验期为35d。分别饲喂真可消化赖氨酸水平(TLys)为1.15%、1.05%、0.95%、0.85%和0.75%的等能(14.23MJ/kg)、等氨基酸模式的玉米-豆粕型日粮。基于协方差分析校正生长猪始重差异,通过测定不同TLys水平对生产性能的影响,确定真可消化赖氨酸需要量。结果表明,当TLys为0.95%时,平均日增重最高(P<0.01),料重比最低(P<0.05);经回归分析,TLys含量为0.95%时,平均日增重达到最大值,而料重比最低。上述结果提示,20～40kg生长猪的TLys需求量为0.95%。     

基于单片机的施药监测系统设计与试验

基于STC12C5A60S2单片机,采用串口通信技术、数据库技术、VS2008软件编程技术,设计并实现了施药监测系统.该系统具有可扩展性,可支持8路模拟传感器和2路数字脉冲式传感器,以采集压力、流量和速度等各种施药参量,并通过LCD显示器实时显示;系统可将各施药参量存入SD卡中,同时通过RS232串口传给PC机;PC机将接收到的数据存储于数据库中,并以表格和图形方式向用户显示施药参量.试验表明:采样周期为1s时,速度经一次校核后测量平均精度达97.7％;测试平台试验和喷药机试验的压力测量平均精度分别为99.3％和98.7％,流量平均测量精度达99.3％.