Inducible macropinocytosis of hyaluronan in B16-F10 melanoma cells

Hyaluronan (HA) is a glycosaminoglycan composed of N-acetylglucosamine and glucuronic acid subunits. Endocytosis is thought to play an essential role in the catabolism of HA due to the intracellular compartmentalization of the HA degrading hyaluronidase enzymes. Previous investigations have shown that keratinocytes, chondrocytes and breast tumor cell lines endocytose HA via the cell surface glycoprotein, CD44. However, other cell types endocytose HA using a CD44-independent mechanism that remains to be defined. The purpose of this study was to investigate HA endocytosis in B16-F10 melanoma cells. We found that B16-F10 melanoma cells expressed CD44 on their surfaces. Unexpectedly, CD44 did not play a role in the endocytosis of HA. Electron microscopy studies revealed that B16-F10 melanoma cells exhibited membrane ruffling, a characteristic feature of macropinocytosis, only after incubating the cells with the HA co-polymer. Moreover, B16-F10 melanoma cells endocytosed HA via macropinocytosis as assessed by drug inhibition studies and the co-localization of fluorescently labeled HA with fluorescent tracers under confocal microscopy. Based on these results, we conclude that induced macropinocytosis may provide a previously unrecognized avenue for HA endocytosis in some cell types.     

BACTERIAL LYSIS OF AUREOCOCCUS ANOPHAGEFFERENS CCMP 1784 (PELAGOPHYCEAE)1

Water samples from Great South Bay, New York, contained biological agents capable of causing the lysis of the brown‐tide alga Aureococcus anophagefferens Hargraves et Sieburth. From these water samples, 32 bacterial isolates were tested for algicidal effects against the algae. Six of the isolates were shown to have algicidal effects against A. anophagefferens. Sequencing of the gene 16S rRNA revealed that the isolates were relatively diverse. Based on their similarity to sequences in repositories, the isolates seem to be closely related to Bacillus, Halomonas, Croceibacter atlanticus, Marinobacter, and an Arctic deep‐sea bacterium.     

Intraspecies genomic groups in Enterococcus faecium and their correlation with origin and pathogenicity

Seventy-eight Enterococcus faecium strains from various sources were characterized by random amplified polymorphic DNA (RAPD)-PCR, amplified fragment length polymorphism (AFLP), and pulsed-field gel electrophoresis (PFGE) analysis of SmaI restriction patterns. Two main genomic groups (I and II) were obtained in both RAPD-PCR and AFLP analyses. DNA-DNA hybridization values between representative strains of both groups demonstrated a mean DNA-DNA reassociation level of 71%. PFGE analysis revealed high genetic strain diversity within the two genomic groups. Only group I contained strains originating from human clinical samples or strains that were vancomycin-resistant or beta-hemolytic. No differentiating phenotypic features between groups I and II were found using the rapid ID 32 STREP system. The two groups could be further subdivided into, respectively, four and three subclusters in both RAPD-PCR and AFLP analyses, and a high correlation was seen between the subclusters generated by these two methods. Subclusters of group I were to some extent correlated with origin, pathogenicity, and bacteriocinogeny of the strains. Host specificity of E. faecium strains was not confirmed.     

Beitr?ge zur Genetik der Buntbl?tterigkeit

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Über die Selbstregulation der Lebewesen

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Die „Anthyllis variegata Sagorski” vom Monte Tonale

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Zwei unbeschriebene Pilze der Flora Krains aus den GattungenPhyllosticta undRamularia

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