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981.
Boric acid (BA) is widely used in various industrial process and can be accessed to nontarget organisms. This study aimed to investigate the insecticidal effects of BA and its toxic activities with respect to immunologic and genotoxic effects using Galleria mellonella larvae as a model. BA concentrations (78.125–10,000 ppm) were administrated to the larvae using the feeding method. Concentration‐dependent mortality was observed in all larval groups. Probit analysis revealed LC30, LC50, and LC70 values to be 112.4, 320.1, and 911.4 ppm, respectively. These concentrations were used in all bioassays. Drastic reductions in total hemocyte counts along with changes in differential hemocyte counts were observed following BA treatment. Cell viability assays showed dose‐dependent reductions in viable cells and an increase in the necrotic and apoptotic ratios after BA treatment. However, mitotic indices of larval hemocytes did not change at all BA concentrations. The cytotoxic effect of BA led to a significant reduction in cellular immune responses such as encapsulation, melanization, and nodulation activities of treated larvae. While BA increased micronucleus ratios at the highest concentration, comet parameters indicating DNA damage increased in G. mellonella larval hemocytes at all concentrations. These report that BA suppresses the immune system of G. mellonella and also poses risks of genotoxicity at high concentrations. 相似文献
982.
Blood samples are commonly obtained in many experimental contexts to measure targets of interest, including hormones, immune factors, growth factors, proteins, and glucose, yet the composition of the blood is dynamically regulated and easily perturbed. One factor that can change the blood composition is the stress response triggered by the sampling procedure, which can contribute to variability in the measures of interest. Here we describe a procedure for blood sampling from the lateral tail vein in the rat. This procedure offers significant advantages over other more commonly used techniques. It permits rapid sampling with minimal pain or invasiveness, without anesthesia or analgesia. Additionally, it can be used to obtain large volume samples (upwards of 1 ml in some rats), and it may be used repeatedly across experimental days. By minimizing the stress response and pain resulting from blood sampling, measures can more accurately reflect the true basal state of the animal, with minimal influence from the sampling procedure itself. 相似文献
983.
984.
Antennal sensilla and their nerve innervation in first‐instar nymphs of Porphyrophora sophorae Arch. (Hemiptera: Coccomorpha: Margarodidae) 下载免费PDF全文
ABSTRACT Porphyrophora (Hemiptera: Coccomorpha: Margarodidae) is a genus of soil‐inhabiting scale insects. The antennal sensilla and their innervation in the first‐instar nymphs of Porphyrophora sophorae were studied using light microscopy and scanning and transmission electron microscopy to understand the function of these sensilla and determine the sensillar innervation feature on these small antennae. The results show that the six‐segmented antennae of these nymphs have 20–23 sensilla which can be morphologically classified into seven types, for example, one Böhm's bristle (Bb), one campaniform sensillum (Ca), one Johnston's organ (Jo), 13–16 aporous sensilla trichodea (St), two coeloconic sensilla (Co), one straight multiporous peg (Mp1), and one curvy multiporous peg (Mp2). According to their function, these sensilla can be categorized into three categories: mechanoreceptors, that is, Bb, Ca, Jo, and St; thermo/hygroreceptors, that is, Co only; and chemoreceptors, that is, Mp1 and Mp2. The dendrites that innervate the Mp1, Mp2, and Co sensilla combine to form a large nerve tract (NT1) in the antennal lumen. Because NT1 extends through and out of the antenna, the somata of these neurons are present in the lymph cavity of the insect's head. The dendrites that innervate the mechanoreceptors form another nerve tract (NT2). The somata of these neurons are located inside the scape and pedicel. J. Morphol. 277:1631–1647, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
985.
Multigenerational experimental simulation of climate change on an economically important insect pest
Long‐term multigenerational experimental simulations of climate change on insect pests of economically and socially important crops are crucial to anticipate challenges for feeding humanity in the not‐so‐far future. Mexican bean weevil Zabrotes subfasciatus, is a worldwide pest that attacks the common bean Phaseolus vulgaris seeds, in crops and storage. We designed a long term (i.e., over 10 generations), experimental simulation of climate change by increasing temperature and CO2 air concentration in controlled conditions according to model predictions for 2100. Higher temperature and CO2 concentrations favored pest''s egg‐to‐adult development survival, even at high female fecundity. It also induced a reduction of fat storage and increase of protein content but did not alter body size. After 10 generations of simulation, genetic adaptation was detected for total lipid content only, however, other traits showed signs of such process. Future experimental designs and methods similar to ours, are key for studying long‐term effects of climate change through multigenerational experimental designs. 相似文献
986.
The petrol-soluble fractions from the branchwood of four Abies alba trees were examined. Only two trees contained sufficient amounts of ‘juvabione-type’ insect juvenile hormone analogues for isolation and characterization. The first contained juvabione (4R, 1′R), 4′-dehydrojuvabione (4R, 1′R) and its 4R, 1′S diastereomer in a ratio of 3:1, and juvabiol (4R, 1′R, 3′S), isojuvabiol (4R, 1′R, 3′R) and epijuvabiol (4R, 1′S, 3′S) in an approximate ratio of 7:3:2. 4′-Dehydroepijuvabione (4R, 1′S) was the only ‘juvabione-type’ compound ioslated from the second tree. If it is accepted that juvabione and epijuvabione are enzymatically reduced forms of dehydrojuvabione and dehydroepijuvabione, respectively; then for these two A. alba our results indicate that only one enzyme which is specific for R chirality at C-1′ is present, since epijuvabione is not observed. 相似文献
987.
988.
Biological invaders can have dramatic effects on the environment and the economy. To most effectively manage these invaders,
we should consider entire pathways, because multiple species are dispersed through the same vectors. In this paper, we use
production-constrained gravity models to describe movement of recreational boaters between lakes – potentially the most important
pathway of overland dispersal for many aquatic organisms. These models are advantageous because they require relatively easily
acquired data, hence are relatively easy to build. We compare linear and non-linear gravity models and show that, despite
their simplicity, they are able to capture important characteristics of the recreational boater pathway. To assess our model,
we compared observed data based on creel surveys and mailed surveys of recreation boaters to the model output. Specifically,
we evaluate four metrics of pathway characteristics: boater traffic to individual lakes, distances traveled to reach these
lakes, Great Lakes usage and movement from the Great Lakes to inland waters. These factors will influence the propagule pressure
(hence the probability of establishment of invasive populations) and the rate of spread across a landscape. The Great Lakes
are of particular importance because they are a major entry point of non-indigenous species from other continents, hence will
act as the origin for further spread across states. The non-linear model had the best fit between model output and empirical
observations with r2 =0.80, r2 =0.35, r2 =0.57, and r2 =0.36 for the four metrics, respectively. For the distances traveled to individual lakes, r2 improved from 0.35 to 0.76 after removal of an outlier. Our results suggest that we were able to capture distances traveled
to most but not all lakes. Thus, we demonstrate that production-constrained gravity models will be generally useful for modeling
invasion pathways between non-contiguous locations. 相似文献
989.
ABSTRACT. . Azadirachtin in blood fed to adult female Aedes aegypti through an artificial membrane does not cause feeding inhibition over a wide dose range (0–200 ng/female), and high doses of ingested azadirachtin fail to inhibit or delay oviposition. However, significant, transient retardation of oocyte growth is observed for up to 72 h after feeding. Immature oocytes are observed in 86% of azadirachtin-fed females decapitated 10 h after a blood meal, whereas 96% of decapitated control females contain maturing oocytes. This suggests that azadirachtin delays the release of one or more factors from the head that regulate oogenesis. We propose that adult females overcome the effect of azadirachtin by rapid metabolism rather than by excretion of the compound, since by 2 h after a blood meal, only 0.1% of ingested azadirachtin was recovered from excreta and 5% recovered from the body. 相似文献
990.
Susan Mopper Michael Beck Daniel Simberloff Peter Stiling 《Evolution; international journal of organic evolution》1995,49(5):810-815
The deme-formation hypothesis states that selection can produce adaptive genetic variation within and among phytophagous insect populations. We conducted three field experiments and tested this prediction by transferring eggs and measuring performance of a mobile leafmining insect, Stilbosis quadricustatella. In Experiment 1, we compared the rate of mine initiation of leafminers transferred to natal and novel sites. In Experiment 2, we compared mine-initiation rate of leafminers transferred to natal and novel host-plant species. In Experiment 3, we compared the mine-initiation rate, mine-completion rate, and sources of mortality of miners transferred to neighboring natal and novel Quercus geminata trees. In the first, second, and third experiments, leafminer larvae initiated significantly more mines at the natal site, on the natal plant species, and on the natal Q. geminata tree, evidence for adaptive differentiation. Furthermore, plant-mediated mortality was significantly lower among miners transferred to natal Q. geminata trees. This result supports a key assumption of the deme-formation hypothesis: insects adapt to the defensive phenotypes of individual trees. However, natural-enemy mortality was significantly higher among miners transferred to natal trees, essentially reversing the plant effect. Therefore, rates of successful mine completion were similar on natal (19%) and novel (17%) trees. This experiment suggests that host plants and natural enemies may represent opposing forces of selection. Leafminers adapted to individual trees may realize a selective advantage only when natural-enemy densities are low. 相似文献