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Larval tobacco hornworms,Manduca sexta (L.), of 2 different colonies were exposed to parasitism by the gregarious endoparasitoid,Cotesia congregata (Say). A comparison was made of parasitoid larval, pre-pupal, and pupal mortality, female and male dry weight and larval
development time. In general, “Maryland” hornworms were more suitable hosts than “North Carolina” hornworms. Although the
presence of dietary nicotine increased parasitoid mortality in individuals reared from hornworms of both colonies, the effect
was more severe among individuals parasitizing the North Carolina hornworms.
Scientific contribution No. 8125, article No. A-5066 of the Maryland Agricultural Experiment Station, Department of Entomology. 相似文献
23.
Applications of intrinsic fluorescence measurements in the study of Ca2+-transport ATPases are reviewed. Since the initial reports showing that the fluorescence emission was sensitive to Ca2+ binding, a substantial amount of work has focused on the use of both steady-state and time-resolved fluorescence spectroscopy to investigate structure-function relationships in sarcoplasmic reticulum and plasma membrane Ca2+-ATPases. These studies have revealed ligand-induced conformational changes, as well as provided information on protein-protein, protein-solvent and/or protein-lipid interactions in different functional states of these proteins. The main results of these studies, as well as possible future prospects are discussed. 相似文献
24.
Maria Ieda Siqueira Linhares Yoshito Eizuru Gildete Patriota de Andrade Ivailda Barbosa Fonseca Luiz Bezerra Carvalho Ivanildo Tenorio Moreira Yoichi Minamishima 《Microbiology and immunology》1994,38(6):475-478
The seroprevalence of human T cell leukemia virus type 1 (HTLV-1) infection was investigated in Brazilians (570): native inhabitants (298) and descendants from Japanese (272) living in Recife and its neighborhoods—North-east of Brazil. Furthermore, polytransfused renal transplanted patients (54) were also examined for the serological status to this virus. The seropositivity to HTLV-1, screened by enzyme-linked immunosorbent assay (ELISA), was low: 1.34% for the local population and 0.73% for the descendants from Japanese. However, the seropositivity for the renal transplanted patients was found to be 11.1%. This higher value suggests that this retrovirus infection seems to be of importance in this clinical condition. 相似文献
25.
Tatiana L. Hernández-Palma Luis Alberto Rueda-Solano Janne K. Valkonen Bibiana Rojas 《Journal of evolutionary biology》2023,36(7):1040-1049
Deimatic displays, where sudden changes in prey appearance elicit aversive predator reactions, have been suggested to occur in many taxa. These (often only putative) displays frequently involve different components that may also serve antipredator functions via other mechanisms (e.g., mimicry, warning signalling, body inflation). The Colombian four-eyed frog, Pleurodema brachyops, has been suggested to gain protection against predation through putative deimatic displays where they inflate and elevate the posterior part of their body revealing eye-like colour markings. We exposed stationary artificial frogs to wild predators to test whether the two components (eyespot/colour markings, defensive posture) of their putative deimatic display, and their combination, provide protection from predation without the sudden change in appearance. We did not detect any obvious additive effect of defensive posture and eyespots/colour markings on predation risk, but found a marginally significant trend for model frogs in the resting posture to be less attacked when displaying eyespots/colour markings than when they were not, suggesting that the presence of colour markings/eyespots may provide some protection on its own. Additionally, we found that models in a resting posture were overall more frequently attacked on the head than models in a defensive posture, indicating that a defensive posture alone could help redirect predator attacks to non-vital parts of the body. The trends found in our study suggest that the different components of P. brachyops' coloration may serve different functions during a deimatic display, but further research is needed to elucidate the role of each component when accompanied by sudden prey movement. 相似文献
26.
Paula Tatiana Lopes Seixas Antonio Jacinto Demuner Luiz Claudio Almeida Barbosa Cristiane Isaac Cerceau Daiane Einhardt Blank Marcelo Henrique Dos Santos Elizeu de Sá Farias Marcelo Coutinho Picanço 《Journal of Applied Entomology》2023,147(2):116-125
Aedes aegypti L. (Diptera: Culicidae) is a vector for serious diseases in tropical regions. This pest is mainly controlled by commercial larvicides but the application of such products has led to environmental problems. Essential oils (EO) have been consistently reported as molecules with insecticidal activity and can be used to produce more environmentally friendly larvicides in the control of A. aegypti. In this study, the larvicidal effect of essential oils (EO) from the leaves of three Artemisia species was evaluated against A. aegypti. The oils were obtained from steam distillation and their chemical composition was determined by gas chromatography–mass spectrometry. The EO of Artemisia camphorata was the most active in the screening bioassay and presented LC50 and LC95 of 64.95 and 74.18 μg ml−1, respectively. In addition, we found that germacrene D-4-ol was the constituent responsible for the toxicity of this EO. Artemisia camphorata EO and its major constituent, germacrene D-4-ol, are promising for the development of natural larvicides against A. aegypti. 相似文献
27.
Arpana Agrawal Sarah J. Brislin Kathleen K. Bucholz Danielle Dick Ronald P. Hart Emma C. Johnson Jacquelyn Meyers Jessica Salvatore Paul Slesinger COGA Collaborators Laura Almasy Tatiana Foroud Alison Goate Victor Hesselbrock John Kramer Samuel Kuperman Alison K. Merikangas John I. Nurnberger Jay Tischfield Howard J. Edenberg Bernice Porjesz 《Genes, Brain & Behavior》2023,22(5):e12864
28.
29.
Thompson JE Kutateladze TG Schuster MC Venegas FD Messmore JM Raines RT 《Bioorganic chemistry》1995,23(4):471-481
Bovine pancreatic ribonuclease A (RNase A) catalyzes the cleavage of the P-O(5') bond in RNA. Although this enzyme has been the object of much landmark work in bioorganic chemistry, the nature of its rate-limiting transition state and its catalytic rate enhancement had been unknown. Here, the value of k(cat)/K(m) for the cleavage of UpA by wild-type RNase A was found to be inversely related to the concentration of added glycerol. In contrast, the values of k(cat)/K(m) for the cleavage of UpA by a sluggish mutant of RNase A and the cleavage of the poor substrate UpOC(6)H(4)-p-NO(2) by wild-type RNase A were found to be independent of glycerol concentration. Yet, UpA cleavage by the wild-type and mutant enzymes was found to have the same dependence on sucrose concentration, indicating that catalysis of UpA cleavage by RNase A is limited by desolvation. The rate of UpA cleavage by RNase A is maximal at pH 6.0, where k(cat) = 1.4 × 10(3) s(-1) and k(cat)/K(m) = 2.3 × 10(6) M(-1)s(-1) at 25°C. At pH 6.0 and 25°C, the uncatalyzed rate of [5,6-(3)H]Up[3,5,8-(3)H]A cleavage was found to be k(uncat) = 5 × 10(-9) s(-1) (t(1/2) = 4 years). Thus, RNase A enhances the rate of UpA cleavage by 3 × 10(11)-fold by binding to the transition state for P-O(5') bond cleavage with a dissociation constant of <2 × 10(-15) M. 相似文献
30.
A complimentary DNA clone encoding the entire human palmitoyl-CoA ligase has been isolated from a liver cDNA library and sequenced in it's entirety. The predicted product is a 699 amino acid protein. Southern analysis utilizing the human palmitoyl-CoA ligase gene as a probe revealed varying degrees of similarity amongst various mammalian species. The palmitoyl-CoA ligase gene is highly expressed in liver, heart, skeletal muscle and kidney, and to a lesser extent in brain, lung, placenta and pancreas. The expression of palmitoyl-CoA ligase in various tissue parallels the function of this enzyme in the metabolism of fatty acids in these tissues. 相似文献