Search

1Two amylase bands were found electrophoretically in adult T. confusum, but the genetic nature of electrophoretic variation among individuals could not be reliably determined. 2. Total amylase activity in larvae increased slowly with age, and decreased sharply before pupation. 3. Activity in adults appeared only 60 hours after emergence and increased quickly to about 2 1/2 times the larval average. In adults deprived of food since emergence, activity did not increase, and in starved adults it rapidly decreased. 4. Possible relationships of amylase activity, developmental rate and individual weight are discussed. Zusammenfassung Amylase-Aktivitat bei Imagines und Larven von Tribolium confusum (Coleoptera, Tenebrionidae) In den Imagines von T. confusum wurden 2 Amylatebander elektrophoretisch festgestellt, doch konnte die Natur individueller elektrophoretischer Variationen nicht sicher aufgeklart werden. Die gesamte Amylaseaktivitat bei den Larven stieg mit dem Alter an und verringerte sich stark vor der Verpuppung. Die Amylaseaktivitat trat bei den Adulten erst 60 h nach dem Schlupfen in Erscheinung und stieg dann schnell auf etwa das 21/2 fache der larvalen Aktivitat. Bei Kafern, die nach dem Schlupfen ohne Nahrung blieben, zeigte sich keine Amylaseaktivitat. Bei solchen, die nach Einsetzen der Aktivitat hungerten, sank sie rapide. Die moglichen Beziehungen zwischen Amylaseaktivitat, Entwicklungsrate und Individualgewicht werden erortert.

A field-collected strain of Tribolium castaneum, initially somewhat more malathion resistant than the control laboratory strain, became much more resistant in less than 8 generations of selection. Resistance is shown to be due to a dominant allele at a single autosomal locus. No deleterious changes in fitness accompanied the increase in resistance. The laboratory strain did not respond to selection apparently for absence of relevant genetic variation. Summary A field collected strain of the flour beetle Tribolium castaneum, called Solet, was found to be more malathion resistant as well as more variable genetically than a control strain, CSbb. In no more than 8 generations of selection by topical application, mortality dropped to very low levels despite a 20-fold increase in dose. LC50 could not be reached even at the highest dose (1 %) which the experimenters could handle without discomfort to themselves. Genetic analyses indicated that malathion resistance in Solet is inherited as a dominant allele at a single, autosomal locus. Selection was ineffective in the control strain, apparently due to the lack of genetic variation at loci controlling resistance. The potential for developing insecticide resistance in Tribolium underlines the need for research on alternative control measures. Zusammenfassung Genetische und okologische Merkmale der Malathion-Resistenz eines Wildstammes des Mehlkafers, Tribolium castaneum (Tenebrionidae, Coleoptera) Ein in einem Lager gesammelter Stamm (“Solet”) von T. castaneum erwies sich als starker Malathion-resistent sowie als genetisch variabler als ein Laborstamm (“CSbb”). In nur 8 mit topicaler Applikation selektionierten Generationen sank die Mortalitat trotz 20-facher Dosis-Steigerung auf ein sehr tiefes Niveau. Die LC50 konnte selbst bei der Hochstdosis von 1 % (mit der eine Handhabung gerade noch ohne eigene Gefahrdung moglich war) nicht erreicht werden. Die genetische Analyse zeigte, das die Malathion-Resistenz beim Stamm Solet auf einem dominanten Allel an einer singularen, autosomalen Stelle beruht. Die Selektion war beim Kontrollstamm, offensichtlich aufgrund fehlender genetischer Variation, wirkungslos. Die Fahigkeit von Tribolium, hohe Insektizidresistenz zu entwickeln, unterstreicht die Notwendigkeit, nach alternativen Bekampfungsmoglichkeiten zu suchen.

A combination of insecticide application with release of insecticide-susceptible males was suggested as an integrated control method aimed at minimizing problems of insecticide resistance. Using malathion-resistant Tribolium castaneum populations as a model, in an experimental situation simulating a stored-products warehouse, we examined the effects of different male-release procedures on resistance. The experiment demonstrates some of the difficulties which may arise in practical application. When an appropriate schedule is found, desirable results may be obtained. The importance of the mode of inheritance of resistance in the target organism is discussed. Zusammenfassung Integrierte Bekampfung von Insektizidresistenz mittels kombinierter genetischer und chemischer Behandlung. Ein Warenhaus-Modell mit Mehlkafern (Tribolium; Tenebrionidae, Coleoptera) Es wird eine Kombination von Insektizidapplikation plus Freilassung von insektizid-empfind-lichen Mannchen als Mittel zur integrierten Bekampfung der Insektizidresistenz vorgeschlagen. Unter Verwendung von malathion-resistenten Tribolium castaneum-Popuhtionen als Modell wurde bei einer Simulation von Warenhausverhaltnissen die Wirkung verschiedener Mannchen-Freilassungen auf die Resistenz des Schadlings getestet. Das Experiment zeigte einige Schwierigkeiten, die bei der praktischen Anwendung entstehen konnen. Die Aufstellung eines geeigneten Planes fuhrt zu den gewunschten Ergebnissen. Die Bedeutung des Erbgeschehens bei dem Vorgang wird diskutiert.

G-protein coupled receptors (GPCRs) are a major group of drug targets for which only one x-ray structure is known (the nondrugable rhodopsin), limiting the application of structure-based drug discovery to GPCRs. In this paper we present the details of PREDICT, a new algorithmic approach for modeling the 3D structure of GPCRs without relying on homology to rhodopsin. PREDICT, which focuses on the transmembrane domain of GPCRs, starts from the primary sequence of the receptor, simultaneously optimizing multiple 'decoy' conformations of the protein in order to find its most stable structure, culminating in a virtual receptor-ligand complex. In this paper we present a comprehensive analysis of three PREDICT models for the dopamine D2, neurokinin NK1, and neuropeptide Y Y1 receptors. A shorter discussion of the CCR3 receptor model is also included. All models were found to be in good agreement with a large body of experimental data. The quality of the PREDICT models, at least for drug discovery purposes, was evaluated by their successful utilization in in-silico screening. Virtual screening using all three PREDICT models yielded enrichment factors 9-fold to 44-fold better than random screening. Namely, the PREDICT models can be used to identify active small-molecule ligands embedded in large compound libraries with an efficiency comparable to that obtained using crystal structures for non-GPCR targets.

G-protein-coupled receptors (GPCRs) are a large and functionally diverse protein superfamily, which form a seven transmembrane (TM) helices bundle with alternating extra-cellular and intracellular loops. GPCRs are considered to be one of the most important groups of drug targets because they are involved in a broad range of body functions and processes and are related to major diseases. In this paper we present a new technology, named PREDICT, for modeling the 3D structure of any GPCR from its amino acid sequence. This approach takes into account both internal protein properties (i.e., the amino acid sequence) and the properties of the membrane environment. Unlike competing approaches, the new technology does not rely on the single known structure of rhodopsin, and is thus capable of predicting novel GPCR conformations. We demonstrate the capabilities of PREDICT in reproducing the known experimental structure of rhodopsin. In principle, PREDICT-generated models offer new opportunities for structure-based drug discovery towards GPCR targets.

G-protein-coupled receptors (GPCRs) are a large and functionally diverse protein superfamily, which form a seven transmembrane (TM) helices bundle with alternating extracellular and intracellular loops. GPCRs are considered to be one of the most important groups of drug targets because they are involved in a broad range of body functions and processes and are related to major diseases. In this paper we present a new technology, named PREDICT, for modeling the 3D structure of any GPCR from its amino acid sequence. This approach takes into account both internal protein properties (i.e., the amino acid sequence) and the properties of the membrane environment. Unlike competing approaches, the new technology does not rely on the single known structure of rhodopsin, and is thus capable of predicting novel GPCR conformations. We demonstrate the capabilities of PREDICT in reproducing the known experimental structure of rhodopsin. In principle, PREDICT-generated models offer new opportunities for structure-based drug discovery towards GPCR targets.

In an attempt to find a causative factor for the increased incidence of otitis media with effusion, a detailed study of 50 cases was conducted. This study included 50 cases of nonpurulent otitis media with effusion requiring ventilating tubes without tonsilloadenoid pathology. A study of these cases revealed an interesting pattern which suggests that antihistamines and decongestants may be causative or precipitating factors in the etiology of otitis media with effusion. A pilot study on the effects of these drugs on mucociliary activity was conducted and revealed further evidence that antihistamines and decongestants interfere with normal mucociliary activity which probably is a factor in abnormal Eustachian tube physiology.