THE RESPONSE TO ‘BLACK-LIGHT’ RADIATION OF SOME COMMON FLIES OF ECONOMIC IMPORTANCE

The responses towards black-light traps of Musca domestica, Fannia canicularis, Lucilia sericata, Calliphora erythrocephala, Phormia terrae-novae and Stomoxys calcitrans were observed by recording the recapture rates of groups of flies released in the laboratory under standardised conditions. Five species showed more than 90% recapture in 3–6 hours, but significantly different response patterns were demonstrated. These differences did not persist beyond a period of 2 1/2 hours from the time of release.

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Zusammenfassung Die Reaktionen von Musca domestica, Fannia canicularis, Lucilia sericata, Calliphora erythrocephala, Phormia terraenovae und Stomoxys calcitrans auf Schwarz-Licht-Fallen wurden an den Wiederfangraten von Gruppen von Fliegen ermittelt, die unter standartisierten Bedingungen im Laboratorium freigelassen worden waren. Bei Darstellung auf einer logarithmischen Skala ergeben die Resultate näherungsweise eine Gerade. Innerhalb der ersten fünf Minuten waren beträchtliche Unterschiede in der Reaktion der einzelnen Arten festzustellen, doch nach 150 Minuten zeigte keine gegenüber anderen signifikante Verteilungsunterschiede. Fünf Arten waren nach drei bis sechs Stunden zu 90%, Fannia nur zu 80% wiedergefangen. Im Inneren von Gebäuden können deshalb Fallen dieses Typs als fast gleichmäßig wirkungsvoll gegenüber beliebigen Fliegenarten bei Routine-Kontrollfängen betrachtet werden.

     

CHANGES OCCURRING IN THE CHEMICAL COMPOSITION OF THE CENTRAL NERVOUS SYSTEM DURING FOETAL AND POST-NATAL DEVELOPMENT OF THE SHEEP

(1) The chemical composition of the CNS (separated into cerebrum, cerebellum, brain stem and spinal cord) was determined in sheep during foetal and post-natal development and in adults. (2) The spinal cord differed from the remainder of the CNS in growing more after the period studied (50-day-old foetuses to 5-week-old lambs) than before it. This was largely attributable to lipid accumulation. (3) Chemical growth (accumulation of DNA, protein and lipid) proceeded linearly in spinal cord, logarithmically in cerebrum and cerebellum while in brain stem growth was described by a sigmoid function. (4) Fat-free dry matter, protein, total lipid, cholesterol and phospholipid concentrations increased progressively in all parts of the CNS but DNA concentrations changed little. In the cerebrum alone there was an increase in DNA concentration during maturation suggesting an increased cell population. Cholesterol was present predominantly in the free form but esters were detected in foetal tissues from 70 up to 120 days gestation. (5) Cerebroside, the characteristic lipid of myelin, increased in concentration soon after 85 days of gestation, up to which point very low values were recorded, the rate varying according to the region of the CNS examined. Rates of increase in total regional cerebroside content were used to identify periods of myelination and the results suggest that there are two periods of peak activity, one about 20 days before birth and the other at 10-20 days after birth. (6) The composition of lipids added during the two phases of myelination and during maturation were characteristically different. In the spinal cord, lipid analyses best reflect changes in myelin composition.     

Evaluation of a Semiautomated System for Direct Fluorescent Antibody Detection of Salmonellae

A semi-automatic system under development by Aerojet Medical and Biological Systems for the direct fluorescent antibody detection of salmonellae was evaluated with various food, feed, and environmental samples. All samples were simultaneously examined by Automated Bioassay System (ABS), manual direct fluorescent antibody procedures and cultural procedures. The ABS gave satisfactory results with the processed samples. It detected all of the culturally positive powdered egg and candy samples with no false negative results and gave only 6.6 and 5.3% false positive rates, respectively. With meatmeal samples the ABS failed to detect one culturally positive specimen that was also positive by manual fluorescent antibody and gave one (1.1%) false-positive result. A high rate of false-negative results was obtained by ABS on unprocessed samples of creek water, poultry, and sausage. Adding another enrichment step to the protocol reduced the false-negative rate considerably but severely increased the false-positive rate. The instruments worked reasonably well, but research is needed to improve enrichment procedures for samples to be processed by the system.     

Modulation of HL-A antigens by anti-HLA antiserum: effects on the cytotoxicity assay and mixed leukocyte reaction.

Modulation of human leukocyte antigen (HLA) was attempted by treating leukocytes with specific anti-HLA antiserum or by their passage through columns coated with anti-HLA or a double layer of HLA-anti-HLA. The modulated cells were resistant to the cytotoxic effects of the anti-HLA, and they were poor stimulators and good responders to allogeneic cells in the unidirectional mixed leukocyte reaction. Modulated cells regained their HLA 16 hr after modulation if kept in cell suspension alone. The proliferative responses of modulated cells to mitogens were as good as non-modulated cells, indicating that modulation was probably not caused by depletion of lymphoid cells. Supernatants of modulated cells that were incubated overnight or preformed HLA-anti-HLA complexes were capable of suppressing and enhancing the MLR of specific cells depending on the dose used. The similarities of modulation of HLA to other lymphocyte receptors and the limitation of application of the modulation phenomenon to transplantation of allogeneic cells are discussed.     

Osmoregulation in Cotton in Response to Water Stress : I. ALTERATIONS IN PHOTOSYNTHESIS, LEAF CONDUCTANCE, TRANSLOCATION, AND ULTRASTRUCTURE

Cotton plants subjected to a series of water deficits exhibited stress adaptation in the form of osmoregulation when plants were subjected to a subsequent drying cycle. After adaptation, the leaf water potential coinciding with zero turgor was considerably lower than in plants that had never experienced a water stress. The relationship between leaf turgor and leaf water potential depended on leaf age.     

Characterization of Vibrio cholerae Isolated from Oysters

Of 790 samples of oyster shellstock freshly harvested during a 12-month survey, 111 (most of which were harvested from June through August) contained Vibrio cholerae non-O1 (611 strains), and seven contained O1 Inaba (11 strains) organisms. None of the V. cholerae strains isolated were enterotoxigenic by immunological and biological tests.     

Effect of floral orifice width and shape on hummingbird-flower interactions

Nectar guides are common among insect-pollinated plants, yet are thought to be rare or absent among hummingbird-pollinated plants. We hypothesize that the lower lips and trumpet-shaped orifices of many hummingbird flowers act as nectar guides to direct hummingbirds to the flowers' nectar and orient the birds for pollination. To test this hypothesis we conducted laboratory experiments using flowers of Monarda didyma (bee balm) and M. fistulosa (wild bergamot), which have orifice widths of about 4 mm and 2 mm, respectively, and latex flowers with orifice widths of 4 mm and 2 mm and three orifice shapes (trumpet, lipped, and lipless). Rubythroated hummingbirds (Archilochus colubris) made fewer errors during bill insertion and spent a smaller proportion of their feeding visit in error at M. didyma flowers than at M. fistulosa flowers, and at unaltered flowers of both species than at flowers with lower lips removed. Handling times were longer at both lipped and lipless flowers of M. didyma than at those of M. fistulosa, and at lipped than at lipless flowers of M. didyma. The average duration of contact between a hummingbird and a flower's anthers and stigma was longer at M. didyma than at M. fistulosa for both lipped and lipless flowers, and at lipped than at lipless M. didyma flowers. Hummingbirds missed the openings of latex flowers with their bills more frequently and spent a greater percentage of their total feeding visit in error at (i) 2-mm than at 4-mm flowers of all three shapes, (ii) lipless flowers than at trumpet or lipped flowers, and (iii) lipped flowers than at trumpet flowers of both widths. The duration of hummingbird/anther contact was longer at (i) 2-mm than at 4-mm flowers of all shapes, (ii) lipped than at trumpet or lipless flowers, and (iii) lipless than at trumpet flowers for both widths. No significant differences in handling times of hummingbirds were observed among any of the latex flower shapes or widths. Our results demonstrate that orifice shapes can act as guides by reducing the frequency of feeding errors by visiting hummingbirds, and that effects of orifice shape on pollination must be considered in conjunction with flower widths and locations of anthers and stigmas.     

The Number and Location of Glycans on Influenza Hemagglutinin Determine Folding and Association with Calnexin and Calreticulin

Calnexin and calreticulin are homologous molecular chaperones that promote proper folding, oligomeric assembly, and quality control of newly synthesized glycoproteins in the endoplasmic reticulum (ER). Both are lectins that bind to substrate glycoproteins that have monoglucosylated N-linked oligosaccharides. Their binding to newly translated influenza virus hemagglutinin (HA), and various mutants thereof, was analyzed in microsomes after in vitro translation and expression in live CHO cells. A large fraction of the HA molecules was found to occur in ternary HA– calnexin–calreticulin complexes. In contrast to calnexin, calreticulin was found to bind primarily to early folding intermediates. Analysis of HA mutants with different numbers and locations of N-linked glycans showed that although the two chaperones share the same carbohydrate specificity, they display distinct binding properties; calreticulin binding depends on the oligosaccharides in the more rapidly folding top/hinge domain of HA whereas calnexin is less discriminating. Calnexin's binding was reduced if the HA was expressed as a soluble anchor-free protein rather than membrane bound. When the co- and posttranslational folding and trimerization of glycosylation mutants was analyzed, it was observed that removal of stem domain glycans caused accelerated folding whereas removal of the top domain glycans (especially the oligosaccharide attached to Asn81) inhibited folding. In summary, the data established that individual N-linked glycans in HA have distinct roles in calnexin/calreticulin binding and in co- and posttranslational folding.     

Heat shock response of the archaebacterium Methanococcus voltae.

The general properties of the heat shock response of the archaebacterium Methanococcus voltae were characterized. The induction of 11 heat shock proteins, with apparent molecular weights ranging from 18,000 to 90,000, occurred optimally at 40 to 50 degrees C. Some of the heat shock proteins were preferentially enriched in either the soluble (cytoplasm) or particulate (membrane) fraction. Alternative stresses (ethanol, hydrogen peroxide, NaCl) stimulated the synthesis of subsets of the heat shock proteins as well as unique proteins. Western blot (immunoblot) analysis, in which antisera to Escherichia coli heat shock proteins (DnaK and GroEL) were used, did not detect any immunologically cross-reactive proteins. In addition, Southern blot analysis did not reveal any homology between M. voltae and four highly conserved heat shock genes, mopB and dnaK from E. coli and hsp70 genes from Drosophila species and Saccharomyces cerevisiae.     

Evidence that functional erythrocyte-type glucose transporters are oligomers

In this study we tested the hypothesis that functional erythrocyte-type glucose transporters (GLUT1) exist as oligomeric complexes by expressing chimeric transporter proteins in Chinese hamster ovary cells harboring endogenous GLUT1 transporters. The chimeric transporters were GLUT1-4c, in which the 29 C-terminal residues of human GLUT1 were replaced by the 30 C-terminal residues of rat skeletal muscle glucose transporter (GLUT4), and GLUT1n-4, containing the N-terminal 199 residues of GLUT1 and the 294 C-terminal residues of GLUT4. Endogenous GLUT1 was quantitatively co-immunoprecipitated by using an anti-GLUT4 C-terminal peptide antibody from detergent extracts of Chinese hamster ovary cells expressing either of the chimeric proteins, as detected by immunoblotting the precipitates with an anti-GLUT1 C-terminal peptide antiserum. No co-immunoprecipitation of native GLUT1 with native GLUT4 from extracts of 3T3-L1 adipocytes, which contain both these transporters, was observed with the same antibody. These data are consistent with the hypothesis that GLUT1 transporters exist as homodimers or higher order oligomers and that a major determinant of oligomerization is located within the first 199 residues of GLUT1.