Die Rolle von Lokomotion und Morphologie in der Habitatwahl der Rohrs?nger (Acrocephalus)

Ohne Zusammenfassung

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The role of locomotion and morphology in the habitat selection of reed warblers (Acrocephalus)

     

Use of colloidal gold particles in double-labeling immunoelectron microscopy of ultrathin frozen tissue sections

Complexes of protein-A with 5 and 16 nm colloidal gold particles (PA/Au5 and PA/Au16) are presented as sensitive and clean immunoprobes for ultrathin frozen sections of slightly fixed tissue. The probes are suitable for indirect labeling and offer the opportunity to mark multiple sites. The best procedure for double labeling was to use the smaller probe first, i.e., antibody 1 - PA/Au5 - antibody 2 - PA/Au16. When this was done, no significant interference between PA/Au5 and PA/Au16 occurred. Using this double-labeling procedure we made an accurate comparison between the subcellular distributions of amylase as a typical secretory protein and of GP-2 a glycoprotein, characteristic for zymogen granule membrane (ZGM) preparations. We prepared two rabbit antibodies against GP-2. One antibody (R x ZGM) was obtained by immunizing with native membrane material. The specificity of R x ZGM was achieved by adsorption with the zymogen granule content subfraction. The other, R x GP-2, was raised against the GP-2 band of the SDS polyacrylamide profile of ZGM. We found that the carbohydrate moiety of GP-2 was involved in the antigenic determinant for R x ZGM, while R x GP-2 was most likely directed against GP-2 polypeptide backbone. THe immunocytochemical observations showed that GP-2, on the one hand, exhibited the characteristics of a membrane protein by its occurrence in the cell membrane, the Golgi membranes, and its association with the membranes of the zymogen granules. On the other hand, GP-2 was present in the contents of the zymogen granules and in the acinar and ductal lumina. Also, a GP-2-like glycoprotein was found in the cannulated pancreatic secretion (Scheffer et al., 1980, Eur. J. Cell Biol. 23:122-128). Hence, GP-2 should be considered as a membrane-associated secretory protein of the rat pancreas.     

Radiation Sterilization: Microbiological Findings from Subprocess Dose Treatment of Disposable Plastic Syringes

S ummary : Disposable plastic hypodermic syringes were taken weekly from commercial production, immediately prior to radiation sterilization, at each of 3 firms. They were irradiated at doses less than that used for sterilization, either with electrons or gamma rays, and tested for sterility. The relationship between the dose applied and the resulting proportion of syringes positive was similar for each firm. Amongst the organisms surviving subnormal process doses was a yeast of unusually high radiation resistance. The possibility of establishing a microbiological quality control procedure based on the routine use of a subprocess dose technique is discussed.     

Production of Rubella Hemagglutinating Antigen in Suspension Culture

Rubella virus specific hemagglutinating antigen was prepared in the fluid phase of suspension cultures. Systems employing baby hamster kidney culture adapted inocula, nonadapted inocula, and cells derived from long-term infected suspension cultures were evaluated. Optimal specific hemagglutinating titers were obtained when kaolin-treated fetal bovine serum was used in the media and when the incoulum had previously been adapted in a suspension culture system. When cultures derived from long-term infected suspension systems were studied, the number of daily harvests in which acceptable titers were present was prolonged. However, titers were generally higher in suspension systems employing cells which had recently been infected.     

Clostridium tetani in a Metropolitan Area: A Limited Survey Incorporating a Simplified in Vitro Identification Test

In a limited survey, three toxigenic and one nontoxigenic strains of Clostridium tetani were isolated from 18 environmental samples from metropolitan Boston. No C. tetani was found in 100 samples of human feces, 20 samples of dog feces, and two samples of horse feces. A simple modification of the halo precipitin test was studied in conjunction with the mouse lethality test for tetanus toxigenicity and was found to be a useful, although not a wholly definitive, technique.     

Ethanol production from glucose byClostridium thermosaccharolyticum strains: Effect of pH and temperature

Summary The fermentation of glucose byClostridium thermosaccharolyticum strains IMG 2811^T, 6544 and 6564 was studied in batch culture in a complex medium at different temperatures in defined and free-floating pH conditions. All the strains ferment 5 g glucose.l^–1 completely. The yield of the fermentation products turned out to be independent of the incubation temperature for strain IMG 2811^T. Strain IMG 6544 produced at 60°C significantly more ethanol and less acetic acid, butyric acid, hydrogen gas and biomass than at lower temperatures. With strain IMG 6564, the opposite effect occurred: ethanol appeared to be the main fermentation product at 45°C; at 60°C less ethanol and more acetic acid, butyric acid and hydrogen gas was formed.Experiments, carried out with strain IMG 6564, at defined pH conditions (between 5.5 and 7) and different temperatures (45, 55 and 60°C) revealed no effect of the incubation temperature, but an important effect of the pH on the product formation. At pH 7, ethanol was the main fermentation product while minor amounts of hydrogen gas, acetic and butyric acid were produced. Lowering the pH gradually to 5.5 resulted in a decrease of ethanol and an increase of biomass, hydrogen gas, acetic, butyric and lactic acids. At pH higher than 7 no growth occurred. Similar conclusions could be drawn for strains IMG 2811^T and 6544.     

LOS oligosaccharide modification enhances dendritic cell responses to meningococcal native outer membrane vesicles expressing a non‐toxic lipid A

Outer membrane vesicles (OMV) are released by many bacteria, and contain immunogenic antigens in addition to harmful inflammatory factors, like lipopolysaccharides. Chemically detoxified OMV have been used in vaccines against Neisseria meningitidis (Nm); however, little is known about their interaction with antigen presenting cells. In this study, we investigated the interaction of Nm OMV with human dendritic cells (DC) to gain further understanding of their biological activity. We engineered a novel serogroup B Nm that is unencapsulated (siaD), expresses pentacylated lipid A (lpxL1), hence conferring reduced toxicity, and expresses an lgtB oligosaccharide structure designed to target OMV to DC via DC‐SIGN. We show that the lgtB moiety is critical for internalization of NOMV by DC. Furthermore, the lgtB moiety significantly enhances DC maturation, IL‐10 and IL‐23 production in the presence of a pentacylated lipid A. While different DC phenotypes were observed for each NOMV, this had little effect on Th1 and Th2 cell differentiation; however, lgtBsignificantly increased Th17 cell expansion in the presence of pentacylated lipid A. We believe that lpxL1/lgtB NOMV should be considered further as a vaccine vector, particularly considering the importance of lgtB in antigen uptake and further human studies on antigen‐specific responses should be considered.