Regulatory peptides in fruit fly midgut

Regulatory peptides were immunolocalized in the midgut of the fruit fly Drosophila melanogaster. Endocrine cells were found to produce six different peptides: allatostatins A, B and C, neuropeptide F, diuretic hormone 31, and the tachykinins. Small neuropeptide-F (sNPF) was found in neurons in the hypocerebral ganglion innervating the anterior midgut, whereas pigment-dispersing factor was found in nerves on the most posterior part of the posterior midgut. Neuropeptide-F (NPF)-producing endocrine cells were located in the anterior and middle midgut and in the very first part of the posterior midgut. All NPF endocrine cells also produced tachykinins. Endocrine cells containing diuretic hormone 31 were found in the caudal half of the posterior midgut; these cells also produced tachykinins. Other endocrine cells produced exclusively tachykinins in the anterior and posterior extemities of the midgut. Allatostatin-immunoreactive endocrine cells were present throughout the midgut. Those in the caudal half of the posterior midgut produced allatostatins A, whereas those in the anterior, middle, and first half of the posterior midgut produced allatostatin C. In the middle of the posterior midgut, some endocrine cells produced both allatostatins A and C. Allatostatin-C-immunoreactive endocrine cells were particularly prominent in the first half of the posterior midgut. Allatostatin B/MIP-immunoreactive cells were not consistently found and, when present, were only weakly immunoreactive, forming a subgroup of the allatostatin-C-immunoreactive cells in the posterior midgut. Previous work on Drosophila and other insect species suggested that (FM)RFamide-immunoreactive endocrine cells in the insect midgut could produce NPF, sNPF, myosuppressin, and/or sulfakinins. Using a combination of specific antisera to these peptides and transgenic fly models, we showed that the endocrine cells in the adult Drosophila midgut produced exclusively NPF. Although the Drosophila insulin gene Ilp3 was abundantly expressed in the midgut, Ilp3 was not expressed in endocrine cells, but in midgut muscle.     

In Vitro Effects of Environmentally Relevant Polybrominated Diphenyl Ether (PBDE) Congeners on Calcium Buffering Mechanisms in Rat Brain

Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame-retardants and have been detected in human blood, adipose tissue, and breast milk. Developmental and long-term exposures to these chemicals may pose a human health risk, especially to children. We have previously demonstrated that polychlorinated biphenyls (PCBs), which are structurally similar to PBDEs and cause neurotoxicity, perturb intracellular signaling events including calcium homeostasis and protein kinase C translocation, which are critical for neuronal function and development of the nervous system. The objective of the present study was to test whether environmentally relevant PBDE congeners 47 and 99 are also capable of disrupting Ca^{2 +} homeostasis. Calcium buffering was determined by measuring ⁴⁵Ca^{2 +} -uptake by microsomes and mitochondria, isolated from adult male rat brain (frontal cortex, cerebellum, hippocampus, and hypothalamus). Results show that PBDEs 47 and 99 inhibit both microsomal and mitochondrial ⁴⁵Ca^{2 +} -uptake in a concentration-dependent manner. The effect of these congeners on ⁴⁵Ca^{2 +} -uptake is similar in all four brain regions though the hypothalamus seems to be slightly more sensitive. Among the two preparations, the congeners inhibited ⁴⁵Ca^{2 +} -uptake in mitochondria to a greater extent than in microsomes. These results indicate that PBDE 47 and PBDE 99 congeners perturb calcium signaling in rat brain in a manner similar to PCB congeners, suggesting a common mode of action of these persistent organic pollutants. The research described in this article has been reviewed by the National Health and Environmental Effects Research Laboratory of the US Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Agency nor does mention of trade names or commercial products constitute endorsement or recommendation for use. These results will be presented at the 21th Biennial Meeting of International Society for Neurochemistry and American Society for Neurochemistry in Cancun, Mexico (August 19–24, 2007). Special issue article in honor of Dr. Frode Fonnum.     

防尘螨药物的实验室药效测试方法

建立防螨药物的药效测试装置与操作方法很有必要。由于尘螨形体微小 ,给防螨药效测试的操作带来诸多困难 ,作者利用螨虫的生物习性及特点 ,建立了布块集螨法、成螨自动分离与净化法、标定计数法 ,布块浸水计数法以及螨虫的驱避和杀灭效果的测试装置与测试方法。结果表明 ,采用成螨自动分离与净化法获得的成螨比例为 ( 94 0± 1 7) %;采用标定计数的精度 (成螨数 刻度 )为 ( 2 0 4± 6 6)只。标定计数 1 0 0 0只螨的实际回收率平均为 ( 75 9± 1 4 6) %,与手工计数无显著性差别 (P >0 0 5 )。实践表明 ,此技术与方法操作简便 ,结果可靠 ,使测试的速度及效果有明显提高     

Production of fine and speciality chemicals: procedure for the estimation of LCIs

Goal, Scope, Background  To improve the environmental performance of chemical products or services, especially via comparisons of chemical products, LCA is a suitable evaluation method. However, no procedure to obtain comprehensive LCI-data on the production of fine and speciality chemicals is available to date, and information on such production processes is scarce. Thus, a procedure was developed for the estimation of LCIs of chemical production process-steps, which relies on only a small amount of input data. Methods  A generic input-output scheme of chemical production process-steps was set up, and equations to calculate inputs and outputs were established. For most parameters in the resulting estimation procedure, default values were derived from on-site data on chemical production processes and from heuristics. Uncertainties in the estimated default values were reflected as best-case and worst-case scenarios. The procedure was applied to a case study comparing the production of two active ingredients used for crop protection. Verification and a sensitivity analysis were carried out. Results and Discussion  It was found that the impacts from the mass and energy flows estimated by the procedure represent a significant share of the impacts assessed in the case study. In a verification, LCI-data from existing processes yielded results within the range of the estimated best-case and worst-case scenarios. Note that verification data could not be obtained for all process steps. From the verification results, it was inferred that mass and energy flows of existing processes for the production of fine and speciality chemicals correspond more frequently to the estimated best-case than to the worst-case scenario. In the sensitivity analysis, solvent demand was found to be the most crucial parameter in the environmental performance of the chemical production processes assessed. Conclusion  Mass and energy flows in LCIs of production processes for fine and speciality chemicals should not be neglected, even if only little information on a process is available. The estimation procedure described here helps to overcome lacking information in a transparent, consistent way. Recommendations and Outlook  Additional verifications and a more detailed estimation of the default parameters are desirable to learn more about the accuracy of the estimation procedure. The procedure should also be applied to case studies to gain insight into the usefulness of the estimation results in different decision-making contexts.     

基因强化在难降解污染物生物处理和修复中的应用

基因强化通过强化降解基因在土著菌群中的水平迁移和传播, 促进土著降解菌群的进化, 改善基因工程菌生物强化作用的稳定性, 提高难降解污染物的生物去除效果。介绍了基因强化的原理-微生物群落内水平基因迁移, 讨论了基因载体、细胞接触条件和环境条件等影响基因强化的因素, 综述了目前基因强化在土壤生物修复和废水生物处理中的应用现状, 并提出了基因强化中存在的问题。     

Cellular and molecular mechanisms mediating the effects of polychlorinated biphenyls on oocyte developmental competence in cattle.

Polychlorinated biphenyls (PCBs) can interfere with normal reproductive functions acting as endocrine disruptors. Aroclor-1254 (A-1254), is a pool of more than 60 congeners used for in vitro studies because its composition is representative of PCBs environmental pollution. We previously demonstrated that the exposure of bovine oocytes to A-1254 during in vitro maturation (IVM) was detrimental not only to the maturation process but also induced a significant increase of polyspermy and a reduction of developmental competence. Therefore, we investigated whether A-1254 acts on two processes that occur during IVM and may be related with its negative effects: maternal mRNA polyadenylation and cortical granules (CGs) migration and exocytosis. Bovine cumulus-oocyte complexes (COCs) were exposed to 0.1 microg/ml of A-1254 during IVM, a level of exposure known to affect oocyte maturation, fertilization, and developmental competence. Oocyte exposure to A-1254 altered the poly(A) tail length of 5 out of 10 genes examined. PCBs effect on mRNA polyadenylation was different depending on the gene considered and resulted either in a shorter or in a longer poly(A) tail. At the end of maturation, Aroclor treated oocytes presented clustered CG in a significantly higher percentage than the control group. In addition, CG exocytosis after 8 hr of fertilization occurred at significantly lower extent in zygotes derived from the exposed group compared to control. Our results indicated that the lower developmental competence of oocytes exposed to PCBs during IVM can be related to the interaction of these contaminants with mechanisms regulating maternal mRNA storage in the ooplasm and normal CGs function.     

Are ants botanists? Ant associative learning of plant chemicals mediates foraging for carbohydrates

1. Although associative learning is widespread across animals, its ecological importance is difficult to assess because learning is rarely studied in the field, where informative cues are juxtaposed against complex backgrounds of uninformative noise. 2. Ants rely heavily on chemical cues for foraging and engage in many ecologically important interactions with plants. Nevertheless, little is known about the role of associative learning of plant chemicals in ant foraging for carbohydrates. 3. In a field setting, the present study investigated whether the distantly related ant species Formica podzolica (Formicinae subfamily) and Tapinoma sessile (Dolichoderinae subfamily) exhibited associative learning of the chemical cues from two co-occurring plant species that are taxonomically and chemically distinct (Asteraceae: Helianthella quinquenervis and Apiaceae: Ligusticum porteri). 4. For two consecutive summers, ants were trained to forage from artificial sugar-rich baits associated with the leaf chemicals from either H. quinquenervis or L. porteri for 24 h, after which a two-choice test was deployed to assess whether ants would be more likely to select baits associated with the same (versus different) plant chemicals on which they had been trained. 5. The present study demonstrates associative learning of chemicals from both plant species, and these effects were consistent between ant species and years; training increased bait occupancy from 42% on the untrained scent to 66% on the trained scent. These results indicate that associative odour-learning may be widespread across ants and serve as an important mechanism mediating ant selection of resources.     

Ultraviolet radiation, toxic chemicals and amphibian population declines

Abstract. As part of an overall ‘biodiversity crisis’, many amphibian populations are in decline throughout the world. Numerous factors have contributed to these declines, including habitat destruction, pathogens, increasing ultraviolet (UV) radiation, introduced non‐native species and contaminants. In this paper we review the contribution of increasing UV radiation and environmental contamination to the global decline of amphibian populations. Both UV radiation and environmental contaminants can affect amphibians at all life stages. Exposure to UV radiation and to certain contaminants can kill amphibians and induce sublethal affects in embryos, larvae and adults. Moreover, UV radiation and contaminants may interact with one another synergistically. Synergistic interactions of UV radiation with contaminants can enhance the detrimental effects of the contaminant and UV radiation.     

几种化学药剂对悬铃木碳氮比值和花芽分化的影响

四种化学药剂处理的悬铃木,其冬季糖和氮含量均高于对照,春季则相反;并对新梢伸长有促进,对粗度有抑制效应;其中经ＧＡ３和乙硫氨酸处理的Ｃ／Ｎ比值增大,新梢成花量增加;乙烯利和２硫尿嘧啶处理的Ｃ／Ｎ比值减小,新梢成花量显著减少。从而为选用减灭悬铃木球果药剂提供理论依据