Expression of CD44 Splice Variants During Lymphocyte Activation and Tumor Progression

Recently, splice variants of CD44 have been described that confer metastatic potential to non-metastasizing rat pancreatic carcinoma and sarcoma cell lines. Using antibodies against variant CD44 (CD44v) sequences, we have examined the expression of variant CD44 glycoproteins on human lymphoid cells and tissues and in colorectal neoplasia. Lymphohematopoietic cells express low levels of CD44v glycoproteins. During the process of lymphocyte activation in vitro and in vivo, expression of CD44v glycoproteins is transiently upregulated. The reaction pattern of various antibodies indicates that these CD44 variants contain the domain encoded by exon v6, which is part of the variant that confers metastatic capability. In human colorectal neoplasia we observed overexpression of CD44 splice variants in all invasive carcinomas. Already at early stages of colorectal tumor progression exon v5 epitopes were overexpressed. Tumor progression was strongly related to expression of CD44 isoforms containing exon v6 encoded domains. The findings establish CD44 variants as tumor progression markers in colorectal cancer.     

Human interferon omega 1: isolation of the gene, expression in Chinese hamster ovary cells and characterization of the recombinant protein.

A gene encoding human interferon omega-1 (IFN-omega 1) was isolated from a cosmid library, sequenced and expressed in Chinese hamster ovary (CHO) cells under the control of an SV40-derived promoter/enhancer sequence. Culture supernatants of stably transfected cell clones contained biologically active IFN-omega 1 at concentrations up to 10 micrograms/l. Amplification of the expression vector containing a dhfr gene under methotrexate selection pressure resulted in yields up to 200 micrograms/l. Production of IFN-omega 1 was further enhanced 2- to 3-fold by propagation of the cells in the presence of n-butyrate. IFN-omega 1 was purified from culture supernatants by monoclonal antibody affinity chromatography. The resulting protein was at least 95% pure as determined by reverse-phase HPLC and size-exclusion HPLC. Sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed two bands of about the same intensity with apparent molecular masses of 24.5 and 22.5 kDa. Upon treatment with peptide:N-glycosidase F, both bands were shifted to lower molecular masses (20.5 and 18.5 kDa), indicating that CHO cell-derived IFN-omega 1 is glycosylated; Asn-78 was identified as the glycosylation site. Analysis of the carbohydrate moiety using glycosidases and lectins revealed the presence of biantennary complex oligosaccharides containing neuraminic acid. Amino acid sequencing showed that only about 40% of the molecules have the expected N-terminus, whereas the others carry two additional amino acids derived from the signal sequence. C-terminal amino acid sequencing using carboxypeptidase P demonstrated that the smaller form of the protein lacks nine amino acids. Disulfide bridges were shown to connect Cys residues 1 and 99 as well as 29 and 139, respectively, as in IFN-alpha. The specific antiviral activity of recombinant, glycosylated human IFN-omega 1 on human cells was 2.6 x 10(8) IU/mg, not significantly different from that of the authentic, human leukocyte-derived protein.     

Underground Vendobionta From Namibia

The late Precambrian fossils from Namibia have generally been regarded as soft-bodied organisms whose three-dimensional preservation resulted from smothering in fluidized sand. The sedimentological context of Pteridinium and Namalia within a sandstone bed, however, allows us to distinguish between two taphocoenoses: (1) winnowed, laterally collapsed, current-transported specimens accumulated as a lag deposit of turbidite-like flows, and (2) specimens 'floating' in the top part of an event bed with their vanes extending upwards to the upper bedding surface. The second taphocoenosis is interpreted as an in situ preserved 'infaunal' community. The immobile underground life habit and the bizarre modes of growth of Pteridinium and Namalia do not fit any extinct or modern group of multicellular organisms. Similar statements can be made for Ernietta and Rangea , thus reviving the Vendobionta hypothesis.     

Der embryonale blutkreislauf und die dotterresorption bei loligo vulgaris

Ohne ZusammenfassungBuchstabenerklärung zu den Abbildungen A After - Av vordere Aorta - Ah hintere Aorta - Au Augen - Da äußere Dottersack - Di innerer Dottersack - De Dotterepithel - Do oberes Dottergefäß - Du unteres Dottergefäß - GC Cerebralganglion - GO Optisches Ganglion - GP Pedalganglion - GV Visceralganglion - Gi Giftdrüse (meist Speicheldrüse genannt) - K Kiemen - KH Kiemenherzen - L Leber - M Mund - Md Mitteldarm - Mh Mantelhöhle - Ml Mantel - SD Sinus des äußeren Dottersacks - Sh hinterer Sinus - SK Kopfsinus - SSt Statocystensinus - St. Statocysten - Sch Schlundkopf - Ss Schalensack - T Tentakel - Ti Tintendrüse - Tr Trichter - V Ventrikel - Vd Vorderdarm - VH Hohlvene - VM Mantelvene - VS Venenschenkel