Quantitative aspects of growth hormone cell maturation in the normal and little mutant mouse

Growth hormone (GH) cells were analyzed by means of ultrastructural morphometry in the pars distalis of pituitary glands from male adult and immature normal (C57BL) and homozygous little (lit/lit) mutant mice. Thin sections were exposed to anti-GH serum and processed immunocytochemically with the colloidal-gold technique. In the pars distalis of adult lit/lit mice, the mean volume density of GH cells/total tissue was 24% of the normal value, granules/GH cells was 58% of normal, and granules/total tissue was only 12% of normal. Deficits in all of these parameters likewise occurred in immature glands, though to a lesser extent than in the adults. The results indicate that the GH deficiency in this mutant reflects quantitative deficits in both the secretory granule content of GH cells, as well as the GH cell content of the gland, with the latter being the more severely affected.     

Disruption of sexual communication in Laspeyresia pomonella1 (codling moth), Grapholitha molesta1 (Oriental fruit moth) and G. Prunivora1 (lesser appleworm) with hollow fiber attractant sources

Emission of (Z)-8-dodecenyl acetate [7% (E) isomer] from hollow fiber dispensers at 0.15 g/ha/day from 1700 points (units of 10 fibers)/ha effects complete disruption of male Grapholitha molesta (Busck) attraction to synthetic lure and virgin females. Attraction of G. prunivora (Walsh) to synthetic lures is also completely disrupted. Emission of (E,E)-8,10-dodecadien-1-ol at 0.05 g/ha/day from 1700 points/ha effects complete disruption of male Laspeyresia pomonella (L.) attraction to synthetic pheromone, to virgin females and prevents mating with tethered females.

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Résumé L'émission du composé (Z)-8-dodecenyl acetate (7% de l'isomère E 8-12 Ac dans le texte), à la dose de 0,15 g/ha/jour, à partir d'émetteurs formés d'une fibre creuse (type Conrel (R)), répartis en 1700 points/ha, chaque point comportant des unités de 10 fibres, annihile complètement l'attraction du mâle de Grapholitha molesta à l'égard de femelles vierges ou de leures chimiques de synthèse. L'attraction de G. prunivora pour des leures synthétiques est également totalement interrompue.L'émission du composé E8 E10-dodécadien-1-ol (E8 E10-12:OH) à la dose de 0,05 g/ha/jour, à partir de 1700 points/ha, entraîne la destruction totale du comportement attractif de Laspeyresia pomonella pour des hormones de synthèse, ou pour des femelles vierges et empêche l'accouplement avec des femelles non mobiles liées par un système adhésif à un dispositif attractif (pherotrap 1C).

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Lepidoptera: Tortricidae: Olethreutinae     

Protease pro region required for folding is a potent inhibitor of the mature enzyme.

alpha-Lytic protease, an extracellular bacterial serine protease, is synthesized with a large pro region that is required in vivo for the proper folding of the protease domain. To allow detailed mechanistic study, we have reconstituted pro region-dependent folding in vitro. The pro region promotes folding of the protease domain in the absence of other protein factors or exogenous energy sources. Surprisingly, we find that the pro region is a high affinity inhibitor of the mature protease. The pro region also inhibits the closely related Streptomyces griseus protease B, but not the more distantly related, yet structurally similar protease, elastase. Based on these data, we suggest a mechanism in which pro region binding reduces the free energy of a late folding transition state having native-like structure.     

Characterization of PTPRG in Knockdown and Phosphatase-Inactive Mutant Mice and Substrate Trapping Analysis of PTPRG in Mammalian Cells

Receptor tyrosine phosphatase gamma (PTPRG, or RPTPγ) is a mammalian receptor-like tyrosine phosphatase which is highly expressed in the nervous system as well as other tissues. Its function and biochemical characteristics remain largely unknown. We created a knockdown (KD) line of this gene in mouse by retroviral insertion that led to 98–99% reduction of RPTPγ gene expression. The knockdown mice displayed antidepressive-like behaviors in the tail-suspension test, confirming observations by Lamprianou et al. 2006. We investigated this phenotype in detail using multiple behavioral assays. To see if the antidepressive-like phenotype was due to the loss of phosphatase activity, we made a knock-in (KI) mouse in which a mutant, RPTPγ C1060S, replaced the wild type. We showed that human wild type RPTPγ protein, expressed and purified, demonstrated tyrosine phosphatase activity, and that the RPTPγ C1060S mutant was completely inactive. Phenotypic analysis showed that the KI mice also displayed some antidepressive-like phenotype. These results lead to a hypothesis that an RPTPγ inhibitor could be a potential treatment for human depressive disorders. In an effort to identify a natural substrate of RPTPγ for use in an assay for identifying inhibitors, “substrate trapping” mutants (C1060S, or D1028A) were studied in binding assays. Expressed in HEK293 cells, these mutant RPTPγs retained a phosphorylated tyrosine residue, whereas similarly expressed wild type RPTPγ did not. This suggested that wild type RPTPγ might auto-dephosphorylate which was confirmed by an in vitro dephosphorylation experiment. Using truncation and mutagenesis studies, we mapped the auto-dephosphorylation to the Y1307 residue in the D2 domain. This novel discovery provides a potential natural substrate peptide for drug screening assays, and also reveals a potential functional regulatory site for RPTPγ. Additional investigation of RPTPγ activity and regulation may lead to a better understanding of the biochemical underpinnings of human depression.     

Distribution of feeding and drinking by groups of captive house mice

Locations of feeding and drinking by social groups of commensal house mice (Mus domesticus), were monitored daily for 30 to 90 minutes for 1 to 3 months. Eighteen foodcups and 18 water bottles were distributed in a 2.4 × 5.1 m population cage. Social groups concentrated their feeding at a few of the foodcups which varied among replicates but drank from most of the water bottles. A mouse feeding at the same sites that are used by others implies that mice use social cues in choosing feeding sites. This is the first documentation of socially influenced choice of feeding sites by wild-caught commensal house mice. A mouse drinking at several sites without concentrating on any sites implies social cues are less important in choosing drinking sites.