致倦库蚊（Culex pipiens quinquefasciatus）引诱产卵信息素的合成及其生物活性

致倦库蚊（Ｃｕｌｅｘｐｉｐｉｅｎｓｑｕｉｎｑｕｅｆａｓｃｉａｔｕｓ）产生的引诱产卵的信息素被鉴定为赤式－６－乙酰氧基－５－十六碳内酯。用环戊酮和十一碳醛经醇醛缩合产生２－（１－羟基十一烷基－１－）环戊酮，再通过拜尔－维利格反应和乙酰化作用合成了这种内酯的赤式和苏式异构体的混合物。合成产物由等比例的四种异构体组成，包括具有活性的赤式－（５Ｒ，６Ｓ）和它的对映异构体，以及另外两个苏式异构体。用合成的信息素对四种（亚种）蚊虫做了引诱产卵的生物测定，发现该产物对同种不同亚种的淡色库蚊（Ｃｘ．ｐｉｐｉｅｎｓｐａｌｌｅｎｓ）和致倦库蚊均有引诱雌蚊产卵的活性，且对前者的引诱力更强，并能保持至少１０天以上；而对同属不同种的三带喙库蚊（Ｃｘ．ｔｒｉｔａｅｎｉｏｒｈｙｎｃｈｕｓ）和另一个属的埃及伊蚊（Ａｅｄｅｓａｅｇｙｐｔｉ）则无活性，表明该信息素具有种的（而非属的）特异性。     

应用^125I标记方形黄鼠蚤并观察对其生理的影响

本文报告应用~(125)I-皮膜喂血法标记方形黄鼠蚤松江亚种Citellophilus tesquorum sungaris获得成功。当该蚤用每毫升猪血1μci的低剂量标记后,在饥饿状态下至第16天,其净计数仍很高,雌蚤平均为460cpm,雄蚤平均为369cpm。实验观察了标记不同剂量的~(125)I对该蚤生命的影响,其结果是:在标记剂量为每毫升猪血1μci～200μci的范围内,对该蚤寿命无影响。标记剂量为每毫升猪血4μci时,该蚤的吸血量与对照组数据接近,说明无不良影响,但产卵量却高于对照组,说明对生殖生理有激活作用。     

伊蚊诱捕器监测法在社区蚊媒监测中的应用

目的探讨伊蚊诱捕器监测指标与传统蚊媒监测指标之间的关系,并分析气候因素对伊蚊密度的影响。方法利用伊蚊诱捕器在广州市海珠区某社区对蚊媒密度进行为期11个月的常规监测。对伊蚊诱捕器监测指标与传统指标进行相关回归分析,并对气候因素（温度、湿度）与伊蚊密度进行回归分析。结果伊蚊诱捕器监测指标诱蚊指数、诱卵指数、诱蚊诱卵指数与传统指标（布雷图指数）之间具有相关性（r=0.758,P=0.007;r=0.667,P=0.025;r=0.758,P=0.007）,并得回归方程Y=1.045＋0.677a-0.590b（Y：布雷图指数,a：诱蚊指数,b：诱卵指数）;对气候因素与伊蚊密度进行回归分析,得到：Y=-18.358＋1.297a（Y：白纹伊蚊总数,a：温度）;Y=-702.837＋47.035a（Y：蚊卵总数,a：温度）。结论伊蚊诱捕器监测指标与传统指标之间具有相关性,伊蚊诱捕器监测法的可信性较强,同时,气候因素是影响伊蚊密度的重要因素。     

Transstadial and horizontal transfer of bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to bacteria-containing water

In a paratransgenic approach, genetically modified bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for bacteria in their guts. In addition to P. stewartii other bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up bacteria from the water they emerged from and transfer the same bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of genetically modified bacteria in the field in a paratransgenic approach against malaria. Further research is needed to determine if the bacteria are also transferred in the same way in nature.     

蛋白质和氨基酸对2种蚊虫产卵选择的影响

目的评价不同蛋白质和氨基酸对我国2种重要媒介蚊虫淡色库蚊和白纹伊蚊雌蚊产卵选择的影响,为新型蚊虫诱卵器的研制提供理论支持。方法在室内测定淡色库蚊和白纹伊蚊对不同种类蛋白质和氨基酸溶液的产卵趋性。结果淡色库蚊怀卵雌蚊偏好在较高浓度的鱼蛋白胨溶液(1000和100mg/L)和酵母浸膏溶液(1000mg/L)中产卵,而10mg/L浓度的鱼蛋白胨溶液能显著引诱白纹伊蚊产卵;苯丙氨酸溶液在1000、100和10mg/L3个实验浓度下均能显著引诱淡色库蚊和白纹伊蚊产卵。结论鱼蛋白胨和苯丙氨酸对淡色库蚊和白纹伊蚊在室内有较好的产卵引诱效果。     

Oviposition signals and their neuroethological correlates in the Culex pipiens complex

Mosquitoes in the Culex pipiens complex (Diptera: Culicidae), especially Cx. pipiens and Culex quinquefasciatus, have successfully exploited the rapid growth of the human population and globalization to their advantage by successfully utilizing man-made habitats, particularly for oviposition. Culex spp. lay over 100 eggs together in a raft. Each egg in the raft produces an apical droplet containing an oviposition attractant, erythro-6-acetoxy-5-hexadecanolide, commonly referred to as Mosquito Oviposition Pheromone (MOP). Here we present a detailed gas chromatography–mass spectrometry (GC–MS) analysis of the apical droplets from six populations that revealed MOP as the most abundant constituent. Subjecting MOP and the remaining 17 most abundant chemical constituents of the droplets from these populations to a Principal Component Analysis (PCA) resolved the populations into two distinct clusters that contained two populations each of Cx. quinquefasciatus and Culex pipiens molestus. The two Culex pipiens pipiens, however, did not resolve into a single cluster, with the Shasta population sorting closer to Cx. quinquefasciatus. Comparing the PCA scores with the genetic evidence from adult females using available molecular markers that have earlier shown to sort various Culex forms, we found that the molecular data support the PCA clustering pattern. Behavioral investigation of the droplet-induced attraction tested in gravid Cx. quinquefasciatus elicited various degrees of oviposition to the droplets from each population. Overall, droplets from all six populations induced higher attraction compared to controls. A detailed time-course analysis of droplet composition in Cx. quinquefasciatus from 6 to 54 h post egg-laying identified MOP again as the main constituent. Finally, our electrophysiological investigation identified MOP as the only biologically active constituent from of the droplets eliciting responses from female antennae. These studies will aid in global efforts to understand the vector biology and evolution that can be exploited to develop novel vector management strategies.     

Ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick, Ornithodoros moubata (Acari: Argasidae)

A blood meal is required for reproduction in most argasid female ticks. The blood meal appears to stimulate an organ in the posterior end to produce a fat body stimulating factor (FSF), which is thought to be an ecdysteroid, to induce vitellogenin (Vg) synthesis. In this study, the relationship of vitellogenesis and ecdysteroids was investigated by measuring Vg and ecdysteroid titers while observing oocyte development and oviposition in mated and virgin females. Oviposition occurred from day 10 after engorgement in mated females and continued up to 40-50 days, whereas egg maturation and oviposition did not occur in virgin females. Vg titers in the hemolymph peaked on day 6 after engorgement and subsequently declined in mated females. Interestingly, Vg synthesis occurred and ovarian development progressed to the development of early vitellogenic oocytes in virgin females but oocyte maturation and oviposition did not occur. Topical application of ecdysteroids induced oviposition in fed virgin females indicating that ecdysteroids may induce oviposition. Concentrations of ecdysteroids for 20 days after engorgement revealed several peaks in mated female whole body extracts, but no peaks in virgin female extracts. In the hemolymph of only mated females, ecdysteroid titers showed two peaks that followed the early peak of ecdysteroids in the whole body on day 4 and 6 after engorgement. In addition, ecdysteroids in the reproductive tissues increased with the development of the ovary in mated females and this increase coincided with the latter peaks of the whole body. These observations indicate that physiological elevation of ecdysteroids accelerate Vg synthesis, and may induce egg maturation and stimulate oviposition in fed mated Ornithodoros moubata females.     

A Laboratory Investigation into Oviposition Responses of Aedes aegypti to Some Common Household Substances and Water from Conspecific Larvae

Background

The surveillance of Dengue vector – Aedes aegypti, is routinely done by using ovitraps (a dark container filled with water and a wooden paddle/towel cloth provided as a oviposition substrate), which indicates the extent of Aedes activity in an area.

Method

The study evaluated the oviposition responses of laboratory bred gravid Aedes aegypti to commonly available household substances by use of ovitrap method.

Results

Oviposition avoidance or deterrence was exhibited by gravid Aedes to ovitraps baited with salt, fenugreek, vinegar, lime juice, hibiscus leaves, radish and curry leaves, whereas positive oviposition response was noticed to waters from conspecific (of the same species) larvae and cumin seeds baited ovitraps.

Conclusion

The study findings may be utilized by researchers for further chemical analysis of the active ingredients of the substances found promising with a view to explore the possibility of their use by community and individuals for Aedes surveillance and control.Key Words: Aedes, Dengue, Oviposition deterrence/attraction     

三带喙库蚊自然种群产卵周期和存活率估测

在上海江湾地区对三带喙库蚊进行连续取样,应用时间序列方法分析雌蚊总数和一定时滞的经产蚊数两序列的互相关性,对自然种群产卵周期和存活率进行估测,并观察气象因素(主要是风速)对分析结果的影响。三带喙库蚊自然种群的产卵周期为2天,产卵周期存活率为0.422～0.457,日存活率为0.650～3.676。风速等气象因素对取样结果分析影响不大。     

Cyclooxygenases expression and distribution in the normal ovary and their role in ovarian cancer in the domestic hen (Gallus domesticus)

Cyclooxygenase (COX) (PTGS) is the rate-limiting enzyme in the biosynthesis of prostaglandins. Two COX isoforms have been identified, COX-1 and COX-2, which show distinct cell-specific expression and regulation. Ovarian cancer is the most lethal gynecological malignancy and the disease is poorly understood due to the lack of suitable animal models. The laying hen spontaneously develops epithelial ovarian cancer with few or no symptoms until the cancer has progresses to a late stage, similar to the human disease. The purpose of this study was to examine the relative expression and distribution of COX-1 and COX-2 in the ovaries of normal hens and in hens with ovarian cancer. The results demonstrate that COX-1 was localized to the granulosa cell layer and cortical interstitium, ovarian surface epithelium (OSE) and postovulatory follicle (POF) of the normal ovary. In ovarian cancer, COX-1 mRNA was significantly increased and COX-1 protein was broadly distributed throughout the tumor stroma. COX-2 protein was localized to the granulosa cell layer in the follicle and the ovarian stroma. COX-2 mRNA expression did not change as a function of age or in ovarian cancer. There was significantly higher expression of COX-1 mRNA in the first POF (POF-1) compared to POF-2 and POF-3. COX-2 mRNA expression was not significantly different among POFs. There was no difference in COX-1 or COX-2 mRNA in the OSE isolated from individual follicles in the follicular hierarchy. The results confirm previous findings of the high expression of COX-1 in ovarian tumors further supporting the laying hen as a model for ovarian cancer, and demonstrate for the first time the high expression of COX-1 in POF-1 which is the source of prostaglandins needed for oviposition.