Bactrocerin‐1: A novel inducible antimicrobial peptide from pupae of oriental fruit fly Bactrocera dorsalis Hendel

A novel antimicrobial peptide, Bactrocerin‐1, was purified and characterized from an immunized dipteran insect, Bactrocera dorsalis. Bactrocerin‐1 has 20 amino acid residues with a mass of 2,325.95 Da. The amino acid sequence of Bactrocerin‐1 showed very high similarity to the active fragment (46V‐65S‐NH₂) of Coleoptericin A. The composition of amino acid residues revealed that Bactrocerin‐1 is a hydrophobic, positively charged, and Lys/Ile/Gly‐rich peptide. Minimal growth inhibition concentration (MIC) measurements for synthesized Bactrocerin‐1 showed a very broad spectrum of anti‐microbial activity against Gram‐positive bacteria, Gram‐negative bacteria, and fungi. Bactrocerin‐1 did not show hemolytic activity toward mouse red blood cells even at a concentration of 50 µM. Analysis of the Helical‐wheel projection and the CD spectrum suggested that Bactrocerin‐1 contains the amphipathic α‐helix. © 2009 Wiley Periodicals, Inc.     

中国芒果输出蒸热杀虫处理研究

中国芒果输出蒸热杀虫处理研究,包括海南产金煌、爱文、象牙和台农1号4个品种芒果鲜果内橘小实蝇Bactrocera dorsalis(Hendel)的卵和不同龄期幼虫的耐热力试验;芒果小规模、大规模蒸热杀虫处理试验;以及蒸热处理对芒果品质的影响等。结果显示,当蒸热室温度逐步达到50℃,芒果果心温度上升至47℃(使用饱和热蒸汽)并保持这一温度时,在不同处理时间(0、5、10、15、20min)条件下,不同品种芒果内橘小实蝇的耐热力由强至弱的发育期依次为2龄幼虫→3龄幼虫→1龄幼虫→卵,其中以金煌芒果(海南产芒果品种中果体最大,平均重量856g)内2龄幼虫的耐热力最强。完全杀灭海南产金煌芒果内橘小实蝇的卵和幼虫的蒸热条件是果心温度保持在47℃和使用饱和热蒸汽处理20min。金煌芒果的小规模、大规模蒸热杀虫处理试验的结果进一步确认和验证,在上述的蒸热处理条件下,总计数量分别为14000头和35000头最具耐热力的供试橘小实蝇2龄幼虫全部被杀灭(死亡率100%),完全可确保其检疫安全。同时,经蒸热杀虫处理后第7d和第12d的金煌芒果鲜果与对照鲜果品质(包括色泽,以及还原糖、蔗糖、总糖、总酸、维生素C和可溶性固形物的含量)的比较测定数据表明,蒸热温度47℃和使用饱和热蒸汽处理20min,除维生素C的含量有微量损失外,基本可保持鲜果的品质不变。     

矿物油乳剂拒避橘小实蝇的有效组分分析

高品质的矿物油乳剂可用于有机食品生产,在害虫综合治理中有良好的应用前景。矿物油是包含多种化学成分的混合物,其组成成分和比例决定其理化性质并关系到其防治病虫害的效果。已有研究报道表明,矿物油乳剂对许多害虫有拒避作用,但其机理及相关性组成成分尚未研究清楚。本实验测定了4种矿物油乳剂即SK绿颖农用喷洒油、加德士-路易夏用油、安波尔喷洒油、法夏乐石蜡油（分别简称为SK,Caltex,Ampol和Citrole油）和Caltex油＜120℃,＞120℃,＜105℃,105~120℃及SK油＜110℃、＞110℃等6种分子蒸馏组分的正构烷烃碳数当量nCy值、碳数分布值及其对橘小实蝇Bactrocera dorsalis的产卵拒避效果。室内生物测定结果显示,橘小实蝇在SK,Caltex,Ampol和Citrole油0.5%水乳液及清水浸蘸处理后的香蕉上平均产卵孔数分别为17.850±1.282,3.400±0.630,15.850±1.439,20.650±1.212和19.050±1.155,在同样方法处理的阳桃上平均产卵孔数分别为15.500±3.969,3.000±0.707,13.750±4.131,17.250±4.385和62.000±4.708。橘小实蝇在6种分子蒸馏组分0.5%水乳液处理后的香蕉上的平均产卵孔数分别为4.400±1.166,8.200±0.583,5.400±1.720,2.400±1.077,4.800±1.594和12.200±2.63,显示不同矿物油的拒避效果差异显著（P<0.05）,拒避效果最好的矿物油的正构烷烃碳数当量nCy值在nC23左右.矿物油对橘小实蝇的产卵拒避效果与其相应的碳数分布值的Spearman等级相关性分析显示,其拒避效果与矿物油中的C23组分的含量呈显著正相关关系（P<0.05）。这可为进一步分析矿物油乳剂拒避害虫的作用成分和探索其机理提供参考。     

纳洛酮翻转刺激大鼠下丘脑弓状核对中缝背核单位活动的影响

实验在麻醉或制动的大鼠上进行。用玻璃微电极记录中缝背核单位活动及其对刺激弓状核的反应,并观察注射纳洛酮的作用。主要结果如下:(1)电刺激弓状核能明显影响中缝背核单位的放电活动,主要表现为抑制;(2)注射纳洛酮能翻转刺激弓状核对中缝背核单位放电的影响;(3)注射纳洛酮使中缝背核单位的自发放电频率显著增加。上述结果提示:刺激弓状核对中缝背核单位放电的影响,可能是通过释放内源性阿片样物质(β-内啡肽)而引起的。     

PHYLOGEOGRAPHIC PATTERNS IN COASTAL NORTH AMERICAN TIGER BEETLES (CICINDELA DORSALIS SAY) INFERRED FROM MITOCHONDRIAL DNA SEQUENCES

Genetic variation was assessed in the tiger beetle, Cicindela dorsalis, by sequencing of three regions of the mtDNA genome. Populations of four morphologically distinguishable subspecies were sampled from 28 representative locations covering almost the entire geographic range of the species in coastal North America. In 78 individuals analyzed for 656 base pairs from four different genes, 17 different haplotypes could be distinguished. A cladistic analysis grouped the haplotype sequences into two main lineages, one from the Atlantic Ocean and one from the Gulf of Mexico. Haplotypes within the two clades were very similar to each other. Most of the characters that distinguished these closely related haplotypes were homoplastic. The geographic distribution of haplotypes did not coincide with the distribution of morphological subspecies, but no evidence for hybridization between two subspecies could be inferred from this observation. The implications of these findings for the evolution of gene sequences at and below the species level are discussed.     

Responses to simulated echoes by neurons in the barn owl's auditory space map

The natural acoustical environment contains many reflective surfaces that give rise to echoes, complicating the task of sound localization and identification. The barn owl (Tyto alba), as a nocturnal predator, relies heavily on its auditory system for tracking and capturing prey in this highly echoic environment. The external nucleus of the owl's inferior colliculus (ICx) contains a retina-like map of space composed of space-specific auditory neurons that have spatially limited receptive fields. We recorded extracellularly from individual space-specific neurons in an attempt to understand the pattern of activity across the ICx in response to a brief direct sound and a simulated echo. Space-specific neurons responded strongly to the direct sound, but their response to a simulated echo was suppressed, typically, if the echo arrived within 5 ms or less of the direct sound. Thus we expect there to be little or no representation within the ICx of echoes arriving within such short delays.Behavioral tests using the owl's natural tendency to turn their head toward a sound source suggested that owls, like their space-specific neurons, similarly localize only the first of two brief sounds. Naive, untrained owls were presented with a pair of sounds in rapid succession from two horizontally-separated speakers. With interstimulus delays of less than 10 ms, the owl consistently turned its head toward the leading speaker. Longer delays elicited head turns to either speaker with approximately equal frequency and in some cases to both speakers sequentially.Abbreviations IC inferior colliculus - ICx external nucleus of the inferior colliculus - ITD interaural time difference - ISI interstimulus interval - LS left speaker - RS right speaker - CS centering speaker - RF receptive field     

桔小实蝇生物学特性

桔小实蝇是一种重要的检疫性果蔬害虫,在厦门一年发生5-6代,以成虫越冬,一年8-10月份为发生高蜂期。本文记述了该虫的形态特征、年生活史、发育历期、发育起点温度,有效积温,生活习性及天敌等。     

刺激中缝背核不同区域对颏舌肌和膈肌的影响

本实验在４８只氨基甲酸惭酯麻醉、断双侧迷走神经的健康家兔上观察了电、化学刺激中缝背核背侧区（ｄＮＲＤ）和腹侧区（ｖＮＲＤ）对颏舌肌和膈肌肌电积分活动的影响。结果如下：（１）长串电脉冲刺激ｄＮＲＤ使颏舌肌和膈肌肌电活动均明显增强;（２）长串电脉冲刺激ｖＮＲＤ时,颏舌肌活动被易化,而膈肌活动则被抑制;（３）在ｄＮＲＤ和ｖＮＲＤ分别微量注射谷氨酸钠,其效应与电刺激结果基本一致。结果提示：（３）在ｄＮＲＤ     

COMPARISON OF INTRASPECIFIC COMPETITION BETWEEN ERUPTIVE AND LATENT AUCHENORRHYCHA (HOMOPTERA) SPECIES ON RICE: SOGATELLA FURCIFERA (DELPHACIDAE) VERSUS RECILIA DORSALIS (DELTOCEPHALIDAE)*

Abstract A comparison of the effects of intraspecific competition between the white‐backed planthopper (WBPH) Sogatella furcifera (Horvath) and the zigzag leaihopper (ZLH) Recilia dorsalis (Motschulsky), as representatives of eruptive and latent Auchenorrhycha (Homoptera) species on rice, was carried out in the laboratory. Crowding during the nymphal stage extended the duration of development of WBPH but not of ZLH. The nymphal survival rate of WBPH, sex ratio, preoviposition period and fecundity of both species were however not affected. The brachypterous percentage of WBPH and nymphal survival of ZLH were significantly reduced under high nymphal density. Crowding during the adult stage reduced fecundity and longevity significantly of both species. Fecundity and longevity were further reduced when combined with high densities during the nymphal stage. Age‐specific life table analysis showed that the integrated effect of crowding on ZLH is stronger than on WBPH. The mechanism of eruptive and latent species' response to crowding during nymph and adult stages is not clearly expressed as a significant difference in fecundity. It is better described as the variation in the intrinsic rate of increase (r_m). Therefore the construction of an age‐specific life table is helpful, and perhaps necessary, to understand these effects. The results showed that the main ecological characteristics of ZLH, as a latent species were its longer immature period, lower total fecundity and decreased and retailed rate of oviposition, hence the lower r_m, as compared with WBPH.     

DISTRIBUTION OF THE ORIENTAL FRUIT FLY (DIPTERA: TEPHRITIDAE) IN YUNNAN PROVINCE*

Abstract The Oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), is a serious pest inaect for vegetables and fruits in Yunnan Province. The trap experiments located in 12 counties of Yunnan indicated that, the geographical distribution of Oriental fruit fly there could be plotted as three distribution zones. To the south of Guannan, Yuanjiang and Rulin is the annual distribution zone. In this region, the Oriental fruit fly completed 4–5 generations per year, and infested the local vegetables and fruits all the year around. To the north of Luku, Dayiao and Qujing is the zone without the insect, where the Oriental fruit fly was not trapped and no fruits infested by the fly were found during the present study. The region between the above two zones was the seasonal distribution zone for the insect. The fruit fly occurred only during May to December in this area, and completed 2–3 generations in this period. The peak abundance of the oriental fruit fly took place from June in Jinghong to October in Yiaoan, along the altitude graduates from the south to the north. In elevation, the Oriental fruit fly was trapped at altitude of 500–2300 m above sea level, in which high trap catches appeared between 500–1000 m. It is proposed that the variations of the fruit fly distribution in altitude and latitude are principally correlated with local temperatures and host plants.