Mapping of mouse gamma crystallin genes on chromosome 1

Restriction fragments analysis of DNA from mouse-hamster somatic-cell hybrid clones revealed that a mouse gamma crystallin cDNA hybridized to genomic sequences located on mouse chromosome 1. Identification of restriction fragment length polymorphisms (RFLPs) in the gamma crystallin sequences of inbred strains of mice permitted the further localization of the gamma crystallin genes (Cryg) to the proximal region of chromosome 1 closely linked to the loci encoding isocitrate dehydrogenase (Idh-1), a low molecular weight (LM) crystallin protein polymorphism (Len-1), and fibronectin (Fn-1). A single recombinant was observed betweenLen-1 and an RFLP in the gamma crystallin gene family, consistent with the hypothesis thatLen-1 is one of the several structural loci encoding gamma crystallin genes.Len-1 is probably located on the centromeric end of theCryg gene family. Linkage ofIdh-1, Cryg, andFn-1 in mice extends the syntenic relationship of those loci to the human, bovine, and rodent genomes and may define a chromosomal region that is generally conserved among mammals. The map position ofCryg, near the eye lens obsolescence (Elo) locus, was confirmed by the discovery that the restriction fragment patterns of gamma crystallin sequences differed between strain C3H/HeJ and the congenic anophthalmic mutant strain, C3H.Elo. Therefore, the gamma crystallin genes were contransferred with the mutantElo gene in the derivation of C3H.Elo. The results establish that LEN-1 is a marker for the gamma crystallin gene family, position the gamma crystallin gene family relative to other markers on mouse chromosome 1, and provide additional evidence that theElo mutation is encoded at a locus closely linked to the gamma crystallin gene cluster. This study found no evidence of recombination hot spots within the gamma crystallin gene cluster.     

Phenological models of development in Pandemis heparana and Adoxophyes orana for timing the application of Insect Growth Regulators with juvenile-hormone activity

Control of leafrollers using Insect Growth Regulators with juvenile-hormone acitivity (IGR) is a major issue in research on Integrated Pest Management in apple orchards. The IGR is applied at the time of emergence of the last-larval instar of leafrollers, thus causing a disturbance of metamorphosis.Simulation models on the development of Pandemis heparana (Denn. et Schiff.) and Adoxophyes orana (F.v.R.) were developed, partly on the basis of experiments, partly on data from literature, to predict the time of emergence of the various stages, particularly of the last-larval instar and the pupa. The models use the state-variable approach, and include only temperature as a driving variable.Simulated curves of emergence of last-instar larvae, pupae and moths corresponded well with observations on field-collected larvae, reared to adult stage in an outdoor insectary. The curves of pheromone trap catches showed a delay relative to the calculated and observed curves for the eclosion of pupae.To investigate whether the time of IGR application could be related to a temperature sum, the relation between emergence curves of last-instar larvae and temperature sums was studied for several years. For this purpose simulated curves were used, because observations on emergence of last-instar covered only a few years.

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Résumé Le contrôle des Tordeuses par les régulateurs de croissance d'Insectes (IGR), à activité d'hormone juvénile, est un progrès majeur dans la recherche pour la lutte intégrée contre les ennemis des vergers de pommiers.L'IGR appliqué lors de l'apparition du dernier stade larvaire des Tordeuses, perturbe ainsi la métamorphose ultérieure. Afin de prévoir le moment d'apparition des différents stades, et plus particulièrement du dernier stade larvaire, des modèles de simulation du développement de Pandemis heparana (Denn. et Schiff.) et Adoxophyes orana (F.v.R.) ont été élaborés à partir d'expériences et en se basant sur des résultats de la littérature.Le modèle est basé sur l'examen de la variable d'état, la température étant la variable discriminante suivie.Les courbes simulées d'apparition des larves de dernier stade, des nymphes et des papillons correspondent aux observations faites sur les larves récoltées dans la nature et élevées jusqu'au stade adulte dans un insectarium en plein air.Le taux de capture dans les pièges à phéromone présente un retard par rapport aux courbes calculées et observées pour l'éclosion des nymphes. Différentes causes peuvent être attribuées à cette différence, mais l'influence d'aucune d'elles n'a été étudiée.Afin de déterminer si le moment de l'application d'IGR peut être lié à une somme de températures, les courbes d'apparition des larves de dernier stade ont été étudiées en relation avec les sommes de températures portant sur plusieurs années. Les observations concernant l'apparition des larves de dernier stade ne couvrant que 2 années, des courbes simulées ont été utilisées à cet effet. L'emploid de la relation liant le moment de l'apparition à la somme des températures permet de n'avoir à calculer que les sommes de températures pour déterminer le moment opportun de l'application des IGR.

     

Interaction of fibronectin-coated beads with attached and spread fibroblasts : Binding, phagocytosis, and cytoskeletal reorganization

After 15 min incubations, binding of 0.8-, 6-, and 16-microns fibronectin-coated latex beads occurred primarily at the margins of chick embryo fibroblasts that previously were attached and spread on fibronectin-coated glass coverslips. Extensive phagocytosis of the smallest beads and some phagocytosis of the larger beads occurred within 2 h. Following binding of the 16-micron beads, there were no changes in overall cell shape or in the distribution of several cytoskeletal proteins. There was, however, a local accumulation of actin and alpha-actinin patches adjacent to the sites where the beads were bound. The formation of alpha-actinin patches could be detected with 6- or 16-microns beads shortly after initial bead binding to the cells, but a similar reorganization of alpha-actinin in response to the binding of 0.8-micron beads was not detected. The patches of alpha-actinin appeared to be associated with membrane ruffles, since such structures were observed by scanning electron microscopy (SEM) to be sites of cell interaction with 6- but not 0.8-micron beads. Also, two other cytoskeletal proteins normally absent from membrane ruffles, tropomyosin and vinculin, were not detected at the sites of cell-bead interaction. No reorganization of vinculin at the cell-bead interaction sites was observed even when the 16-microns beads remained bound at the cell surfaces for up to 6 h. Nevertheless, prominent vinculin plaques were observed at the marginal attachment sites on the ventral cell surfaces. Consequently, formation of mature focal adhesions may be restricted to linear regions of cell-substratum interaction.     

Effects of in vitro growth phase on the pathogenesis of Salmonella typhimurium in mice

The growth phase of a bacterial (Salmonella typhimurium) culture was shown to have pronounced effects on the pathogenic properties of the harvested bacteria. Salmonellae obtained from a culture in primary (exponential) growth phase (PP) were more readily cleared from the blood and more readily killed by phagocytes than were salmonellae obtained from a more slowly growing secondary growth phase (SP) culture. PP salmonellae were observed to cause death of mice sooner than SP salmonellae. This appeared to be because the more rapid growth of PP, as compared to SP, salmonellae continued in the liver and spleen for several hours following intravenous injection, and more than compensated for their high in vivo death rate. As a result, within 4 h there were approximately 10-fold more live salmonellae in the spleens and livers of mice that had received PP, as compared to SP, salmonellae. This 10-fold difference was maintained until the death of the mice, indicating that after the first 4 h post-inoculation, the net in vivo growth of the salmonellae was the same regardless of their growth phase in the inoculating culture. This transition between PP and SP salmonellae occurred long before a dense stationary phase culture was obtained. Salmonellae grown in minimal media exhibited the biological properties of SP salmonellae and never entered as rapid a growth phase as did salmonellae in complete media.     

Recombinant human interleukin 1 alpha: purification and biological characterization

Interleukin 1 (IL 1) is a polypeptide hormone produced by activated macrophages that affects many different cell types involved in immune and inflammatory responses. The cloning and expression of a murine IL 1 cDNA in Escherichia coli encoding a polypeptide precursor of 270 amino acids has been reported, and expression of the carboxy-terminal 156 amino acids of this precursor in E. coli yields biologically active IL 1. By using the murine IL 1 cDNA as a probe, we have isolated its human homolog from cDNA generated to lipopolysaccharide-stimulated human leukocyte mRNA. Nucleotide sequence analysis of this cDNA predicts a protein of analysis of this cDNA predicts a protein of 271 amino acids (termed IL 1 alpha) which shows congruent to 61% homology to its murine counterpart but only 27% homology to a recently characterized human IL 1 precursor (IL 1 beta). We have expressed the carboxy-terminal 154 amino acids of IL 1 alpha in E. coli, purified this protein to homogeneity, and have compared it with pure recombinant murine IL 1 in several different IL 1 assays based on murine and human cells. Recombinant IL 1 is capable of stimulating T cell and fibroblast proliferation and inducing fibroblast collagenase and prostaglandin production, thus proving that a single molecule has many of the activities previously ascribed to only partially purified IL 1 preparations. Our results indicate that there exists a family of at least two human IL 1 genes (alpha and beta) whose dissimilar protein products have similar biological activities.     

Metabolic adaptations in goat mammary tissue during pregnancy and lactation

Metabolic adaptations of goat mammary tissue during pregnancy and lactation were monitored in serial biopsies of the tissue. Changes in the synthetic capacity of secretory cells were studied by combining measurements of enzyme activities with short-term culture of mammary explants to measure lactose, casein and total protein synthesis. By these criteria, the main phase of mammary differentiation began in late pregnancy and was essentially complete by Week 5 of lactation, coinciding with the achievement of peak milk yield. While milk yield declined after Week 5, the activities of key enzymes expressed per mg DNA and the rates of lactose and casein synthesis in mammary explants were maintained over a considerable period. The results suggest that changes in the synthetic capacity of epithelial cells may account for much of the rise in milk yield in early lactation, but are not responsible for the declining phase of milk production characteristic of lactation in ruminants.     

Lectin-induced modulation of the antibody response to type III pneumococcal polysaccharide

Several lectins were tested for their capacity to alter the antibody response to type III pneumococcal polysaccharide (SSS-III). The antibody response was enhanced by concanavalin A (Con A), phytohemagglutinin (PHA), as well as lectins from Phytolacca americana (Pa-2), Pisum sativum (PSA), and Lens culinaris (LCH), when these lectins were given 2 days after immunization with SSS-III; however, suppression was obtained when Con A and Pa-2 were given at the time of immunization. By contrast the lectins from Vicia villosa (VVL) and Bauhinia purpurea (BPA) did not alter the antibody response. Since the lectins PSA and LCH bind to the same monosaccharide as Con A, whereas the other lectins bind to different monosaccharides, these findings indicate that there is no relationship between nominal monosaccharide specificity and the capacity to modulate the antibody response. Substantial increases in the magnitude of the IgG₁ antibody response was noted after the administration of Con A whereas profound enhancement of IgG_2a antibody response was noted after PHA was given.