冠状病毒IBV和噬菌体MS2在饱和多孔介质中的运移规律

为研究病毒在土壤中的运移机理,选择鸡的传染性支气管炎冠状病毒(IBV)和噬菌体(MS2)为材料,采用土柱模拟实验研究2种病毒在不同输入方式(IBV脉冲,MS2阶跃)、不同饱和多孔介质中的运移规律.结果表明,IBV在饱和玻璃珠中的运移有少量滞留和延迟;MS2在饱和砂土中的运移随着离子强度的不同而不同,存在两个临界点,分别为0.065mol/L和0.080mol/L.在离子强度从0.002mol/L升高到0.065mol/L时,病毒吸附随着离子强度的增加而迅速增加;离子强度在0.065～0.080mol/L时,病毒吸附随着离子强度的增加而迅速降低;当离子强度超过临界点0.08mol/L后,随着离子强度的增加病毒吸附缓慢增加.在相同pH值和离子强度的不同介质中,IBV比MS2吸附和滞留较多.     

Reassessing the role of the honeybee (Apis mellifera) Dufour's gland in egg marking

Dufour's gland secretion may allow worker honeybees to discriminate between queen-laid and worker-laid eggs. To investigate this, we combined the chemical analysis of individually treated eggs with an egg removal bioassay. We partitioned queen Dufour's gland into hydrocarbon and ester fractions. The bioassay showed that worker-laid eggs treated with either whole gland extract, ester fraction or synthetic gland esters were removed more slowly than untreated worker-laid eggs. However, the effect only lasted up to 20 h. Worker-laid eggs treated with the hydrocarbon fraction were removed at the same rate as untreated eggs. The amount of ester which reduced the egg removal rate was far higher than that naturally found on queen-laid or worker-laid eggs, and at natural ester levels no effect was found. Our results indicate that esters or hydrocarbons probably do not function as the signal by which eggs can be discriminated.     

Pre- and post-hatch trophic egg production in the subsocial burrower bug, Canthophorus niveimarginatus (Heteroptera: Cydnidae)

In recent years, three terrestrial bugs, Adomerus triguttulus and Sehirus cinctus (Cydnidae) and the closely related Parastrachia japonensis (Parastrachiidae), have been the focus of several fascinating studies because of the remarkable, extensive parental care they were found to display. This care includes egg and nymph guarding, production of trophic eggs, unfertilized, low cost eggs that are used as food by newly hatched nymphs, and progressive provisioning of the host seed. In this study, we have investigated yet a third related Asian cydnid, Canthophorus niveimarginatus, with regard to the possible occurrence of some or all of these complex traits in order to assess how widespread these maternal investment patterns are in this group of insects and to better understand the implications of their manifestations from an evolutionary context. Manipulative experiments were carried out in the lab to determine whether females provision nests. Observational and egg removal studies were carried out to determine whether trophic eggs are produced, and, if they are, their possible impact on nymphal success. The findings revealed that C. niveimarginatus does, in fact, progressively provision young, and this species also displays all of the other behaviors associated with extended parental care in subsocial insects. Moreover, unlike the other two related species, which place trophic eggs on the surface of the original egg mass, C. niveimarginatus produces both pre- and post-hatch trophic eggs. Nymphs deprived of access to post-hatch trophic eggs had significantly lower body weight and survival rate than those that fed on them. To our knowledge, this is the first time the production of both pre- and post-hatch trophic eggs has been demonstrated in insects outside the Hymenoptera. In this paper, we qualitatively and quantitatively demonstrate the provisioning behavior and patterns of trophic egg production in C. niveimarginatus. When and how trophic eggs are produced and delivered to young should have important correlations with the ecological and life history constraints under which a species has evolved. Thus, we also discuss the possible ecological and life history factors that favor the evolution of post-hatch trophic eggs.     

Color polymorphism in a land snail Cepaea nemoralis (Pulmonata: Helicidae) as viewed by potential avian predators

Avian predation is one of the most probable factors maintaining polymorphism of shell coloration in Cepaea nemoralis. This assumption is justified by the fact that birds frequently forage on snails and their prey choice varies with morph coloration. However, in all preceding studies, the conspicuousness of morphs was determined only by using human vision which is significantly different from birds’ visual perception. In this study, we assessed how birds perceive colors of four Cepaea nemoralis morphs using physiological models of avian color vision. We calculated combined chromatic and achromatic contrast between shells and three habitat background types as a measure of shell conspicuousness. The degree of background color matching in Cepaea nemoralis depended on both shell morph and habitat type. On average, banded morphs were more conspicuous than unbanded morphs. Morphs were the most cryptic against dry vegetation and the most conspicuous on bare ground. We also found a significant interaction between habitat type and color morph. The relative conspicuousness of shell morphs depended on habitat and was the most variable against green vegetation. Our study provides the first insight into how potential avian predators view Cepaea nemoralis morphs. The results are discussed in light of multiple hypotheses explaining selective predation on Cepaea nemoralis morphs.     

五氯酚和双酚A联合作用对斑马鱼胚胎发育的毒性

采用斑马鱼胚胎技术和毒性11配比及不同毒性配比的方法,对环境雌激素类物质五氯酚(PCP)和双酚A(BPA)进行联合毒性测试.结果表明,PCP和BPA在0hpf染毒且毒性效应配比11时,24h死亡表现为协同作用,72h孵化抑制率表现为相加作用PCP和BPA不同毒性效应配比时,6hpf染毒的24h血流障碍有拮抗作用存在,而0hpf染毒的32h囊肿表现有协同作用存在.并且,6hpf的联合作用与0hpf联合作用相比,24h血流障碍、32h血流障碍和32h囊肿这3种毒性效应都有所降低.     

Increased incidence of cytogenetic abnormalities in chorionic villus samples from pregnancies established by in vitro fertilization and embryo transfer (IVF–ET)

We studied 201 pregnancies that were established by in vitro fertilization and embryo transfer (IVF–ET) and compared the frequency of cytogenetic abnormalities with that found in a large control population matched for indication group (advanced maternal age) and time of sampling. A total of 252 IVF–ET fetuses were cytogenetically analysed by either chorionic villus sampling (CVS; n = 80) or amniocentesis (n = 172). Eleven chromosome abnormalities were found in the CVS group (13·8 per cent); among them, a 45, X/46, X, dic(q11)/46, X, del(Y)(q11) mosaic that was found in an IVF pregnancy established by intracytoplasmic sperm injection (ICSI), four cases of trisomy 21, and three cases of trisomy 7 confined to the placenta. The results indicate a statistically significant three-to five-fold increase in both confined placental abnormalities (P<0·008) and true fetal chromosome anomalies (P<0·04). In the amniocentesis group, identical rates (1·7 per cent) of chromosome abnormalities were found in the IVF–ET and control groups. It is concluded that late first trimester, but not early second trimester, IVF–ET pregnancies are characterized by an increased frequency of cytogenetic abnormalities found at prenatal diagnosis.     

Parental conflict and blue egg coloration in a seabird

When both parents provide offspring care, equal sharing of costly parental duties may enhance reproductive success. This is crucial for longlived species, where increased parental effort in current reproduction profoundly affects future reproduction. Indication of reproductive value or willingness to invest in reproduction may promote matching responses by mates, thus reducing the conflict over care. In birds with biparental care, blue-green eggshell color may function as a signal of reproductive value that affects parental effort, as predicted by the signaling hypothesis of blue-green eggshell coloration. However, this hypothesis has not been explored during incubation, when the potential stimulus of egg color is present, and has been little studied in longlived birds. We experimentally studied if egg color affected incubation patterns in the blue-footed booby, a longlived species with biparental care and blue eggs. We exchanged fresh eggs between nests of the same laying date and recorded parental incubation effort on the following 4 days. Although egg color did not affect male effort, original eggshell color was correlated with pair matching in incubation. Exchanged eggshell color did not affect incubation patterns. This suggests that biliverdin-based egg coloration reflects female quality features that are associated with pair incubation effort or that blue-footed boobies mate assortatively high-quality pairs incubating more colorful clutches. An intriguing possibility is that egg coloration facilitates an equal sharing of incubation, the signal being functional only during a short period close to laying. Results also suggest that indication of reproductive value reduces the conflict over care.     

The leaching of additive-derived flame retardants (FRs) from plastics in avian digestive fluids: The significant risk of highly lipophilic FRs

The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to organisms. In the present study, the leaching of incorporated flame retardants(FRs),including polybrominated diphenyl ethers(PBDEs), alternative brominated FRs(AFRs), and phosphate flame retardants(PFRs), from different sizes of recycled acrylonitrile-butadienestyrene(ABS) polymer were investigated in avian digestive fluids. The impact of co-ingested sediment on the leaching of additive-derived FRs in digestive fluids was also explored. In the recycled ABS, BDE 209(715 μg/g) and 1, 2-bis(2,4,6-tribromophenoxy) ethane(BTBPE,1766 μg/g) had the highest concentrations among all target FRs. The leaching proportions of FRs were higher in finer sizes of ABS. The leaching proportions of FRs from recycled ABS increased with elevated logK OWof FRs. In the tests with coexisted ABS and sediment, hexato deca-BDEs, BTBPE, and decabromodiphenyl ethane(DBDPE) migrated from ABS to sediment, which resulted in the less bioaccessible fractions of these FRs in gut fluids. More lipophilic chemicals tended to be adsorbed by sediment from ABS. The results suggest the migration of additive-derived FRs from plastics to other indigestible materials in digestive fluids. The findings in this study provide insights into the transfer of additive-derived FRs from plastics to birds, and indicate the significant contribution of FR-incorporated plastics to bioaccumulation of highly lipophilic FRs.     

Effects of height and habitat type on egg parasitism by Trichogramma minutum and T. pretiosum (Hymenoptera: Trichogrammatidae)

Heliothis virescens (Fabricius) eggs were sampled to determine the effects of height and habitat type (soybean field vs. uncultivated vegetation) on rates of p arasitism by Trichogramma minutum Riley and T. pretiosum Riley. The potentially confounding effects of plant associations and host density and distribution were eliminated by sampling with laboratory-produced eggs deposited on cloths, rather than with eggs naturally deposited by endemic hosts.A 3-way contingency table analysis showed that parasitism (whether the egg cloths were parasitized or not) was significantly associated with height and habitat type in 1981, with higher rates of parasitism in the uncultivated habitat and at the greater height. Parasitism was independent of height and habitat in 1982. Rates of parasitism by the two Trichogramma species were not clearly associated with habitat type, but were associated with height. T. minutum consistently parasitized egg cloths positioned at greater heights than those parasitized by T. pretiosum. While the behavioral mechanisms responsible are unknown, this inter-specific difference could have important implications with regard to selecting the most suitable of these two Trichogramma species for a particular inundative release program.     

Mid–trimester hyperechogenic bowel in a fetus of Japanese origin carrying a new mutation of CFTR gene (L548Q)

We present a case of a fetus with hyperechogenic bowel, in which the L548Q mutation was detected in the mother of Japanese origin and the ΔF508 mutation in the father of Caucasian origin. The fetus proved to be compound heterozygous. Research into cystic fibrosis transmembrane conductance regulator (CFTR) mutations in this case was triggered by the fact that the fetus had a characteristic hyperechogenic bowel image with normal karyotype and no indications of intrauterine infections. Hyperechogenic bowel is highly indicative of a CFTR gene mutation. The incidence of cystic fibrosis (CF) in fetuses with mid-trimester hyperechogenic bowel is 5%, but once the most frequent mutations have been accounted for, rarer mutations must be investigated. Copyright © 2006 John Wiley & Sons, Ltd.     

Occurrence and variation of egg cannibalism in brown trout Salmo trutta

Egg cannibalism is a common behavior among fish taxa and is largely studied in species with parental care. Heterocannibalism and filial cannibalism have both been reported in salmonids, a group with no extended parental care, but the topic remained somewhat under-documented, especially in brown trout (Salmo trutta). In the present study, 83 spawning events were recorded finely with high-resolution video in three natural populations. Redd covering dynamics by females and the timing of cannibalism showed that eggs were vulnerable mainly during the first 120 s after spawning. Cannibalism occurred in 25% of spawnings and was principally perpetrated by peripherals but the sires also cannibalized their brood, especially after multiple mating. The probability of cannibalism increased with operational sex ratio but did not correlate with the date in spawning season. Occurrence of cannibalism also differed between populations. Our results suggest that such behavior is frequent and may reduce the fitness of parents. Its evolutionary implications for population ecology should be considered, since it appeared to be controlled by environmental and spatial factors.     

抗生素废水对Q67的急性毒性和对AHH的诱导

利用Q67发光菌 (Vibrio qinghaiensissp .Nov . Q67)和鲤鱼肝微粒体芳烃羟化酶 (AHH)体外诱导实验评估某酸化处理工艺对抗生素废水的处理效果 ,探讨除利用常规的理化指标监测水质外 ,生物监测的必要性。      

海洋青鳉胚胎不同发育阶段对120#燃料油毒性敏感性的比较

本研究考查了120#燃料油分散液（WAFs）对海洋青鳉（Oryzias melastigma）胚胎的毒性效应,测试其各发育阶段对WAFs的敏感性。将6 hpf（受精后小时数）、18 hpf和30 hpf的海洋青鳉胚胎分别暴露于不同浓度的WAFs中,并于暴露之后的12、24、48、72、96 h进行观察、记录并计算胚胎的蓝囊综合症（blue sac disease,简称BSD）指数、孵化率、心率以及半数致死浓度LC₅₀值等指标。结果表明,WAFs暴露可以对海洋青鳉胚胎发育产生明显的毒性影响,包括发育畸形、孵化率和心率下降、死亡率上升等现象,并伴随着明显的时间-剂量效应。各项指标对于WAFs暴露的敏感性各不相同,以BSD指数和孵化率变化更为明显。胚胎对于120#燃料油毒性的敏感性随着发育呈现逐渐下降的趋势,随着暴露起点的延后,毒性影响逐渐减小。但是,WAFs对海洋青鳉胚胎心率的影响主要作用于心脏发育阶段。     

Estimating the abundance and egg production of spawning winter flounder (Pseudopleuronectes americanus) in the Niantic River,CT for use in the assessment of impact at Millstone Nuclear Power Station

The winter flounder is a coastal flatfish with spawning populations associated with specific estuaries or coastal areas. Because of its stock structure, this species is susceptible to localized impacts, including power plant entrainment of larvae. Winter flounder rank second in fish larvae entrained at the Millstone Nuclear Power Station (MNPS), located on Long Island Sound in Waterford, CT, USA. Because of its importance to the state’s fisheries, the population spawning in the nearby Niantic River was selected for impact assessment studies in the early 1970s. Northeast Utilities has consistently monitored annual abundance of adult spawners, characterizing relative abundance by trawl catch-per-unit-effort (CPUE) and absolute abundance using mark and recapture data with the Jolly model for demographically open populations. Trends in these two independent but highly correlated indices provide short-term assessments of winter flounder abundance. Abundance of winter flounder peaked in the early 1980s, but as fishing mortality increased to high levels in the late 1980s, their numbers declined thereafter and presently are very low. Information on sex ratio, length-frequency distribution, and spawning condition allow for calculation of annual egg production using a length-fecundity relationship. This forms the basis for estimating production loss due to larval entrainment, which is used as input to a long-term assessment model of power plant impact, discussed in an accompanying paper (Lorda et al., 2000: Lorda, E., Danila, D.J., Miller, J.D., 2000. Application of a population dynamics model to the probabilistic assessment of CWIS effects of Millstone Nuclear Power Station (Waterford, CT) on a nearby winter flounder spawning stock. Environmental Science & Policy 3, S471–S481).