Effect ofin vitro differentiation on proteoglycan structure in cultured human monocytes

Parellel toin vitro differentiation of human monocytes into macrophage-like cells, the cells change their synthesis of glycosaminoglycans from chondroitin 4-sulfate to highly sulfated chondroitin sulfate, containing 4,6-disulfatedN-acetylgalactosamine units [Kolsetet al. (1983) Biochem J 210:661–67]. After exposure of monocyte cultures to [³⁵S]sulfate for 24h either from the onset of cultivation, prior to differentiation, or from day 4, after differentiation,³⁵S-macromolecules from medium and cell-layer were isolated and characterized. The cell-layer of day 5 cultures contained both proteoglycans and free polysaccharide chains, while the³⁵S-macromolecules present in the cell-layer of day 1 cultures and in medium of both monocytes and macrophage-like cells were almost exclusively of proteoglycan nature. Proteoglycans produced by macrophage-like cells were of larger size than the monocyte proteoglycans, most likely due to an increased polysaccharide chain length. These proteoglycans, in contrast to the monocyte-derived species, also showed affinity for fibronectin at physiological ionic strength.     

Palyno-stratigraphy of the Ketewaka coalfield (Lower Permian), Tanzania

Palynological studies of outcrop and borehole samples from coal-bearing Karroo (Lower Permian) deposits in the Ketewaka area of southwest Tanzania show a distinct change in the composition of spore/pollen assemblages approximately in the middle of the sequence, the most prominent feature being differences in the representation of monosaccate and disaccate species. This is in line with results of earlier studies in the adjacent Mchuchuma area.The change in spore/pollen content is taken as evidence of a considerable floral change affecting an extensive area and probably climatically controlled.The floral change coincides with a distinct change in sedimentation, from sand with coal to mud or clay with coal, except for a part of the Ketewaka area, where sandy sediments continued to be deposited.     

HBs antigen in the blood donors of Calvados. Epidemiologic study and surveillance of the patients

175 Chronic HBs Ag carriers have been discovered in the blood donors of the Calvados blood transfusion center from 1971 to 1979. 72 of them (41%) gave their consent for a clinical and biological study at the end of 1979, after receiving a convocation letter. This work had two aims: - to study the epidemiological factors in this population. - to evaluate the clinical and biological consequences of persistent antigenemia. 1. Epidemiological Study. Most results agree with the literature (higher prevalence in male, age, stay in endemic countries) but some results disagree for several reasons: our donors are all volunteers, HBs Ag prevalence is low in our region, most of the patients are caucasian and with life conditions and habits which may explain some particularities in contagion. Furthermore, the relative number of blood donors found every year as chronic HBs Ag carriers, does not increase in our country. 2. The Clinical and Biological follow-up of 62 HBs Ag carriers (alcoholics excluded) was carried out for 4,3 years on average. No patients developed clinical and biological features of chronic liver disease. After a mean term follow-up, we conclude that the asymptomatic HBs Ag carriers state seems not to be of bad prognostic. Since long term complications cannot be excluded, the follow-up of these patients must be maintained.     

Coal TitParus ater song repertoires and the Beau Geste hypothesis

At least 44 different song types were recorded in a population of Coal Tits at Klaebu in central Norway. Each male sang up to 14 different types. In testing the Beau Geste hypothesis the following predictions were made: (1) Territorial males tend to change song type when moving from one song post to another. (2) The tendency to change song type when moving from one song post to another increases with the distance between the song posts. (3) Territory holders prefer inconspicuous song posts that reduce the chances of being instantly detected by possible intruders and prospectors. However, none of these predictions were confirmed by the data analyses. The singing behaviour of the Coal Tit does therefore not support the Beau Geste hypothesis.

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Zusammenfassung In einer Population der Tannenmeise bei Klaebu, Mittelnorwegen, wurden mindestens 44 unterschiedliche Gesangstypen registriert. Einzelne Männchen sangen bis zu 14 Typen. Um die Beau-Geste-Hypothese (ein Sänger täuscht durch verschiedenen Gesangstypen die Anwesenheit mehrerer Individuen vor) zu testen, wurden folgende Annahmen geprüft: (1) Territoriale Männchen neigen dazu, ihren Gesangstyp zu ändern, wenn sie die Singwarte wechseln. (2) Die Tendenz, zwischen Gesangstypen zu wechseln, ist bei Männchen am größten, die während einer Gesangsphase mehr als eine Singwarte benutzen. (3) Territoriale Männchen benützen unauffällige Singwarten, um nicht so schnell von möglichen Eindringlingen oder reviersuchenden Artgenossen entdeckt zu werden. Die Analyse der Daten ergab jedoch für keine dieser Annahmen eine Bestätigung. Somit unterstützt das Verhalten singender Tannenmeisen die Hypothese nicht.

     

Alginate Biosynthesis Factories in Pseudomonas fluorescens: Localization and Correlation with Alginate Production Level

Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner and outer membranes. In the present study, we developed a method by which the porin AlgE was detected by immunogold labeling and transmission electron microscopy. Localization of the AlgE protein was found to depend on the presence of other proteins in the multiprotein complex. No correlation was found between the number of alginate factories and the alginate production level, nor were the numbers of these factories affected in an algC mutant that is unable to produce the precursor needed for alginate biosynthesis. Precursor availability and growth phase thus seem to be the main determinants for the alginate production rate in our strain. Clustering analysis demonstrated that the alginate multiprotein complexes were not distributed randomly over the entire outer cell membrane surface.