Febs Letters

doi: 10.1016/0014-5793(91)80926-Tpmid: N/A

Petersen, Simone; Russ, Martina; Reinauer, Hans; Eckel, Jürgen

doi: 10.1016/0014-5793(91)80927-Upmid: 1907567

The present study examined the mRNA levels of glucose transporter Glut4 and G‐protein Gs α‐subunit in isolated ventricular myocytes from lean and genetically obese (fa/fa) Zucker rats and streptozotocin‐diabetic rats. In obese animals the amount of transcripts coding for Glut4 increased to 122±6% of lean controls, whereas the mRNA coding for Gs α‐subunit decreased by 42±12%. An unaltered level of Gs mRNA was observed in insulin deficient rats. When cardiomyocytes from normal rats were treated with insulin, the Glut4 transcript level increased by 48±5%, whereas the Gs mRNA level decreased by 55±8%. The findings suggest that insulin may act as a potential regulator of Glut4 and Gs mRNA expression in the cardiac cell.

Harada, Masataka; Sisido, Masahiko; Hirose, Junzo; Nakanishi, Mamoru

doi: 10.1016/0014-5793(91)80928-Vpmid: 1864380

A monoclonal antibody (Z1H01) for an oligopeptide carrying an azobenzene group, was prepared under conditions where the azobenzene group is in the trans form. The antibody bound the hapten peptide effectively when the hapten peptide is in the trans form (K=5 × 107 M−1), but the antibody released the hapten under irradiation with UV light where the hapten is in the cis form. The antibody bound the hapten again, when the hapten reverted to the trans form after irradiation with visible light.

King, Ian A.; Magee, Anthony I.; Rees, David A.; Buxton, Roger S.

doi: 10.1016/0014-5793(91)80929-Wpmid: 1713860

Amino acid sequencing of a 48/46 kDa glycoprotein from human plantar callus, recognised by antisera raised against the desmosomal cadherins DGII/III has revealed N‐terminal homology to the DNA‐derived sequence of human and bovine DGII/III. However, a tryptic fragment has homology only with a bovine clone. We propose that there are two classes of DGII/III‐like molecule, that represented by the bovine cDNA clone and the 48/46 kDa protein, a monoclonal antibody against which stains mainly the suprabasal layers of human epidermis, and that represented by the human cDNA clone, identified by a monoclonal antibody which stains uniformly the living layers of the epidermis.

André, Lars; Hemming, Anna; Adler, Lennart

doi: 10.1016/0014-5793(91)80930-2pmid: 1864360

Production of glycerol and a key enzyme in glycerol production, glycerol 3‐phosphate dehydrogenase (NAD+) (GPD), was studied in Saccharomyces cerevisiae cultured in basal media or media of high salinity, with glucose, raffinose or ethanol as the sole carbon source. At high salinity, glycerol production was stimulated with all carbon sources and glycerol was accumulated to high intracellular concentration in cells grown on glucose and raffinose. Cells grown on ethanol accumulated glycerol to a lower level but showed an increased content of trehalose at high salinity. However, the trehalose concentration corresponded only to about 20% of the glycerol level, and did not compensate for the shortfall in intracellular osmolyte content. Immunoblot analysis demonstrated an increased production of GPD at high salinity. This increase was osmotically mediated but was lower when glycerol was substituted for NaCl or sorbitol as the stress‐solute. The enzyme also appeared to be subject to glucose repression; the specific activity of GPD was significantly lower in cells grown on glucose, than on raffinose or ethanol.

Hokke, Cornelis H.; Kamerling, Johannis P.; van Dedem, Gijs W.K.; Vliegenthart, Johannes F.G.

doi: 10.1016/0014-5793(91)80931-Rpmid: 1907570

An approach is presented for the determination of the branch location of 1 or 2 extra N‐acetyllactosamine units in sialo N‐linked carbohydrate chains from glycoproteins. Tetraantennary oligosaccharides containing extra N‐acetyllactosamine units were digested with endo‐β‐galactosidase, followed by treatment with N‐acetyl‐β‐glucosaminidase, yielding products which could be analysed by 1H‐NMR spectroscopy, thereby giving conclusive data about the location of the extra units in the intact structures.

Pérez-Tur, Jordi; Barat, Ana; Ramos, Milagros; Ramirez, Galo

doi: 10.1016/0014-5793(91)80932-Spmid: 1864375

Bacterial chondroitinases (both ABC and AC types) release asymmetric and globular forms of AChE from chick skeletal muscle samples. Heparinases, however, including heparitinase I, fail to do so under different incubation conditions. These results do not support the direct implication of the heparin/heparan sulfate family of GAGs in the interaction of the different AChE molecular forms with the muscle ECM. GAGs of the chondroitin/dermatan sulfate group could however be involved, either directly or indirectly, in the attachment of the AChE collagen‐like tail to the muscle basal lamina.

Uhlinger, David J.; Burnham, David N.; Mullins, Richard E.; Kalmar, John R.; Cutler, Christopher W.; Arnold, Roland R.; Lambeth, J.David; Merrill, Alfred H.

doi: 10.1016/0014-5793(91)80933-Tpmid: 1650714

Activated polymorphonuclear leukocytes have been associated with neoplasia, atherogenesis and reperfusion injury. Since some of these conditions are also correlated with dietary fat, we examined the functional characteristics of leukocytes isolated from subjects before and after consumption of a lipid‐rich meal. There was up to 2‐fold greater superoxide generation in response to agonists in leukocytes obtained post‐prandially; the maximum increase was observed about 4 h after eating and followed the peak (2–4 h) in serum triglycerides. Neutrophils isolated post‐prandially also exhibited impaired chemotaxis and defective bacterial killing, but normal phagocytosis. These findings provide a new variable that should be considered in studies of leukocytes.

Konami, Yukiko; Yamamoto, Kazuo; Toyoshima, Satoshi; Osawa, Toshiaki

doi: 10.1016/0014-5793(91)80934-Upmid: 1864376

The complete amino acid sequence of the Laburnum alpinum di‐N‐acetylchitobiose‐binding lectin was determined by using a protein sequencer after digestion with endoproteinases Lys‐C and Asp‐N, and compared with those of other leguminous plant lectins.

Inokuchi, Jin-ichi; Kumamoto, Yukihiro; Jimbo, Masayuki; Shimeno, Hiroshi; Nagamatsu, Atsuo

doi: 10.1016/0014-5793(91)80935-Vpmid: 1864377

The effect of sphingosine (SPH) on the adhesive properties of Lewis lung carcinoma (3LL) cells was investigated using plastic precoated with the extracellular matrix proteins, laminin, fibronectin, or type IV collagen. Treatment of 3LL cells with SPH (0.5–10 μM) resulted in a dose‐dependent decrease in the ability to bind to laminin and type IV collagen but had little or no effect on atachment to fibronectin. Phorbol 12‐myristate 13‐acetate (PMA) selectively enhanced attachment of 3LL cells to laminin and collagen. The inhibitory effect of SPH on attachment to both proteins was competitively antagonized by PMA. These results suggest that SPH acts as a negative effector for cell attachment to laminin and collagen, and that the cell attachment process to both proteins might be regulated in part by protein kinase C.