Expression of three neuropeptide genes (SfEH,SfETH, and SfCCAP) in response to insecticide stress on the white-backed planthopper Sogatella furcifera (Hemiptera: Delphacidae)

Insect neuropeptides are involved in many important developmental processes. Here, we cloned three neuropeptide genes (SfEH, SfETH, and SfCCAP) from Sogatella furcifera (Horváth) and analyzed the relative expression levels of these genes through Real-time Quantitative polymerase chain reaction (RT-qPCR) during different developmental stages and in different wing types of S. furcifera following exposure to sublethal concentrations (LC₁₀ and LC₂₅) of methylaminoavermectin benzoate. The results revealed that the three neuropeptide genes (SfEH, SfETH, and SfCCAP) of S. furcifera contained open reading frame sequences of 222, 636, and 408 bp, encoding 73, 211, and 135 amino acids, respectively. Moreover, the expression of SfEH and SfETH reached its peak on day 3 of the 5^th instar nymph stage, while the SfCCAP expressed pinnacle on 40 min after eclosion. Furthermore, the relative expression levels of the three genes were in the following order: SfEH, short-winged female > long-winged female > long-winged male; SfETH, long-winged female > short-winged female > long-winged male; and SfCCAP, short-winged female > long-winged male > short-winged female. Upon calculating the relative expression of the three peptide genes after 24 and 48 h of treatment with sublethal concentrations of methylaminoavermectin benzoate, it was found that the relative mRNA expression levels of SfEH and SfETH declined upon LC₁₀ treatment but increased upon LC₂₅ treatment. Meanwhile, the relative mRNA expression level of SfCCAP declined upon both LC₁₀ and LC₂₅ treatments. This result will help us understand the effects of pesticides on insect growth and development at the molecular level.     

Studies on Physiological and Biochemical Properties of Female Specific Serum Protein and Its Immunocytochemical Localization in Carassius auratus cuvieri(Temminck & Schlegel)

Female-specific serum protein(FSSP)is normally present in the sera of female fish,but it is notfound in males.However,estradiol benzoate(EB)was found to induce the appearance of FSSP inmale fish and immature female fish.Massive doses of FSSP caused a rapid increase in FSSP.Ultrastructural examination of the liver indicated an extensive proliferation of the rough endoplasmicreticulum and a decrease in glycogen and lipid droplets after EB injection.A preparative PAGE for isolating highly purified FSSP from the serum of EB-treated fish,Carassiusauratus cuvieri(Temminck & Schlegel),is described.Purified FSSP obtained from EB-induced O-crucian fish has a molecular weight of 466,000±4,000(n=10),while that in mature female serumis 480,000±40,000(n=2).FSSP appears to be a dimer,with the size of the possible monomerbeing 240,000±8,000(n=6).SDS-PAGE on gradient gels indicated that sera from males given multiple(12)injections of EBcontain a main band with a molecular weight of 147,000±6,000(n=6).However,the same serumsamples provided three bands of protein on the PAGE gels.Antiserum was raised against the electrophoretically purified FSSP.The resulting antibody formeda single,continuous precipitation line with sera from EB-treated males and vitellogenic females,butnot with that from normal males.lmmunocytochemistry(PAP method)was used to locate FSSP in the liver and ovary of maturefemales and the liver of EB-treated males.Strongly positive particles were found clustered in groupsaround liver cell nuclei under light microscopy,and the yolk granules in the oocytes were also filledwith positive particles.     

Characterization of a novel antimycotic agent,cinnamyl benzoate,using yeast-phase Sporothrix schenckii

Cinnamyl benzoate specifically inhibited the growth of yeast-phase cells of the pathogenic fungus Sporothrix schenckii. A commercially available antimycotic agent, miconazole nitrate, released large amounts of K⁺ and P_i from S. schenckii probably due to it damaging the cell membrane, but no such release was observed with cinnamyl benzoate or with another commercial antimycotic agent, Tolnaftate. The sterol content of cells treated with cinnamyl benzoate and Tolnaftate was decreased and large amounts of squalene accumulated in the cells. Cinnamyl benzoate may therefore inhibit sterol synthesis in S. schenckii.The authors are with the Department of Applied Microbial Technology, Kumamoto Institute of Technology, lkeda 4-22-1, Kumamoto 860, Japan.     

Potential of Foliar,Dip, and Injection Applications of Avermectins for Control of Plant-Parasitic Nematodes

Studies were conducted to determine the potential of two avermectin compounds, abamectin and emamectin benzoate, for controlling plant-parasitic nematodes when applied by three methods: foliar spray, root dip, and pseudostem injection. Experiments were conducted against Meloidogyne incognita on tomato, M. javanica on banana, and Radopholus similis on banana. Foliar applications of both avermectins to banana and tomato were not effective for controlling any of the nematodes evaluated. Root dips of banana and tomato were moderately effective for controlling M. incognita on tomato and R. similis on banana. Injections (1 ml) of avermectins into banana pseudostems were effective for controlling M. javanica and R similis, and were comparable to control achieved with a conventional chemical nematicide, fenamiphos. Injections of 125 to 2,000 μg/plant effectively controlled one or both nematodes on banana; abamectin was more effective than emamectin benzoate for controlling nematodes.     

Effects of early embryonic exposure to genistein on male copulatory behavior and vasotocin system of Japanese quail

Genistein is a phytoestrogen, particularly abundant in soybeans that can bind estrogen receptors and sex hormone binding proteins, exerting both estrogenic and antiestrogenic activity. In this study we used the Japanese quail embryo as a test end-point to investigate the effects of early embryonic exposure to genistein on male copulatory behavior and on vasotocin parvocellular system. Both differentiate by the organizational effects of estradiol during development and may therefore represent an optimal model to study the effects of xenoestrogens. We injected two doses of genistein (100 and 1000 microg) into the yolk of 3-day-old Japanese quail eggs. Other eggs were treated with either 25 microg of estradiol benzoate or sesame oil as positive and negative controls. At the age of 6 weeks, behavioral tests revealed a significant decrease of all aspects of copulatory behavior (in comparison to the control group) in estradiol-treated birds. In contrast, genistein-treated animals demonstrated various degrees of decrease in the mean frequencies of some aspects of the sexual behavior. The computerized analysis of vasotocin innervation in medial preoptic, stria terminalis and lateral septum nuclei revealed a statistically significant decreased immunoreactivity in treated animals compared to control ones. These results demonstrate that genistein, similarly to estradiol, has an organizational effect on quail parvocellular vasotocin system and on copulatory behavior. In conclusion, present results confirm, in this avian model, that embryonic exposure to phytoestrogens may have life-long effects on sexual differentiation of brain structures and behaviors.     

Co-metabolism of di- and trichlorobenzoates in a 2-chlorobenzoate-degrading bacterial culture: Effect of the position and number of halo-substituents

The degradative properties towards chlorobenzoates by a 2-chlorobenzoate-degrading mixed culture (2MC) were investigated. Although 2MC did not grow on 2,3,5-; 2,3,6- and 2,4,6-trichlorobenzoates, it was able to completely oxidise 2,3,5-trichlorobenzoate and 2,5-dichlorobenzoate. This was degraded through the intermediate formation of 4-chlorocatechol and 3-cis,cis-chloromuconate, suggesting a dioxygenation in 1,2 position. 4-Chlorobenzoate; 3,4- and 2,6-dichlorobenzoate; 2,4,6- and 2,3,6-trichlorobenzoate did not undergo any co-metabolic transformation, the only 2,4-dichlorobenzoate was scarcely transformed into a dichlorinated phenol as end-product. 2MC was constituted of three prominent species: Stenotrophomonas maltophilia, Cupriavidus necator and Flavobacterium sp. Ring-hydroxylating dioxygenase genes (BenA) were retrieved in S. maltophilia and C. necator, indicating the presence of a “modified ortho pathway” in the culture. On the basis of its degradative properties, 2MC could be a good candidate for use in the removal of ortho- and/or meta-chlorobenzoates that are the major end-products of PCB co-metabolism.     

应用原子力显微镜分析苯甲酸钠生物毒性

应用原子力显微镜(Atomic force microscope, AFM)在单细胞水平上研究食品防腐剂苯甲酸钠(Sodium benzoate, SB)的生物毒性, 从可视化的角度分析了淋巴细胞与不同浓度SB作用不同时间后其形态及其膜超微结构的影响。结果与正常淋巴细胞相比, 随着与淋巴细胞作用的SB浓度和作用时间的增加, 细胞形态及细胞膜明显发生改变, 其超微结构也趋复杂。经SB作用后的细胞高低差Rp-v、均方根粗糙度Rq、平均粗糙度Ra、平均高度4个几何参数值均明显发生改变。对经SB作用后的淋巴细胞进行统计学分析, 并探讨了其作用机制。     

Caffeine Formulation for Avian Repellency

Abstract: Nonlethal management alternatives are needed to reduce avian depredation of agricultural crops. Caffeine has promise as an effective, economical, and environmentally safe avian repellent, yet formulation improvements are needed for field applications. We included sodium benzoate in subsequent formulations to enhance the solubility of caffeine. Red-winged blackbirds (Agelaius phoeniceus) discriminated between untreated rice and rice treated with 250 ppm or 10,000 ppm caffeine and sodium benzoate in captivity. We observed a positive concentration-response relationship among birds offered rice treated with 250 ppm, 1,000 ppm, 2,500 ppm, 5,000 ppm, 10,000 ppm, or 20,000 ppm caffeine and sodium benzoate. Relative to the pretreatment of the concentration-response test, repellency was >85% for rice treated with our 2,500- to 20,000-ppm treatments. We conducted seed germination experiments and associated residue analyses to evaluate the potential phytotoxicity of various caffeine formulations under controlled environmental conditions. The optimized formulation enhanced the solubility of tank mixtures and ameliorated the negative impacts of seed treatments to germination. Our caffeine formulation provides an applicable, nonlethal alternative for managing blackbird impacts to agricultural production.     

Inhibition of human matriptase by eglin c variants

Based on the enzyme specificity of matriptase, a type II transmembrane serine protease (TTSP) overexpressed in epithelial tumors, we screened a cDNA library expressing variants of the protease inhibitor eglin c in order to identify potent matriptase inhibitors. The most potent of these, R₁K₄′-eglin, which had the wild-type Pro⁴⁵ (P1 position) and Tyr⁴⁹ (P4′ position) residues replaced with Arg and Lys, respectively, led to the production of a selective, high affinity (K_i of 4 nM) and proteolytically stable inhibitor of matriptase. Screening for eglin c variants could yield specific, potent and stable inhibitors to matriptase and to other members of the TTSP family.