SYNTHESIS OF GLYCOPROTEIN, GLYCOLIPID, PROTEIN, AND LIPID IN SYNCHRONIZED L5178Y CELLS

Synthesis of four macromolecular classes found in membranes—glycoprotein, glycolipid, protein, and lipid—was measured as a function of time of the cell cycle in synchronized L5178Y cells. Incorporation of leucine, choline, fucose, glucosamine, or thymidine into the cells, protein, nucleic acid, or lipid was measured by pulse-labeling for ½ hr at ½ hr intervals after release from the mitotic block. The amount of protein, lipid, glycoprotein, or glycolipid released or secreted into the medium by the L5178Y cells was also measured as a function of time of the cell cycle. Cellular protein was found to be synthesized throughout the cell cycle, with the highest synthesis occurring in the S period; synthesis was depressed in the M period. Cellular glycoprotein was synthesized at approximately the same times as protein, except that the rates of glycoprotein synthesis in the S period relative to other periods were much greater than for protein. Secreted protein was synthesized throughout the cell cycle without any general pattern, except that secretion was elevated in the late S and G2 periods. Secreted glycoprotein was similar to secreted protein. Cellular lipid and cellular glycolipid were synthesized almost exclusively in the G2 and M periods; there was no synthesis in the G1 and S periods. Release or secretion of glycolipid and lipid also occurred in the G2 and M periods

Role of extracellular histones in the cardiomyopathy of sepsis

The purpose of this study was to define the relationship in polymicrobial sepsis (in adult male C57BL/6 mice) between heart dysfunction and the appearance in plasma of extracellular histones. Procedures included induction of sepsis by cecal ligation and puncture and measurement of heart function using echocardiogram/Doppler parameters. We assessed the ability of histones to cause disequilibrium in the redox status and intracellular [Ca2+]i levels in cardiomyocytes (CMs) (from mice and rats). We also studied the ability of histones to disturb both functional and electrical responses of hearts perfused with histones. Main findings revealed that extracellular histones appearing in septic plasma required C5a receptors, polymorphonuclear leukocytes (PMNs), and the Nachtâ , LRRâ , and PYDâ domainsâ containing protein 3 (NLRP3) inflammasome. In vitro exposure of CMs to histones caused loss of homeostasis of the redox system and in [Ca2+]i, as wellas defects in mitochondrial function. Perfusion of hearts with histones caused electrical and functional dysfunction. Finally, in vivo neutralization of histones in septic mice markedly reduced the parameters of heart dysfunction. Histones caused dysfunction in hearts during polymicrobial sepsis. These events could be attenuated by histone neutralization, suggesting that histones may be targets in the setting of sepsis to reduce cardiac dysfunction.â Kalbitz, M., Grailer, J. J., Fattahi, F., Jajou, L., Herron, T. J., Campbell, K. F., Zetoune, F. S., Bosmann, M., Sarma, J. V., Huberâ Lang, M., Gebhard, F., Loaiza, R., Valdivia, H. H., Jalife, J., Russell, M. W., Ward, P. A. Role of extracellular histones in the cardiomyopathy of sepsis. FASEB J. 29, 2185â 2193 (2015). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154273/1/fsb2fj14268730.pd

Ganglioside composition and histology of a spontaneous metastatic brain tumour in the VM mouse

Glycosphingolipid abnormalities have long been implicated in tumour malignancy and metastasis. Gangliosides are a family of sialic acid-containing glycosphingolipids that modulate cell–cell and cell–matrix interactions. Histology and ganglioside composition were examined in a natural brain tumour of the VM mouse strain. The tumour is distinguished from other metastatic tumour models because it arose spontaneously and metastasizes to several organs including brain and spinal cord after subcutaneous inoculation of tumour tissue in the flank. By electron microscopy, the tumour consisted of cells (15 to 20 μm in diameter) that had slightly indented nuclei and scant cytoplasm. The presence of smooth membranes with an absence of junctional complexes was a characteristic ultrastructural feature. No positive immunostaining was found for glial or neuronal markers. The total ganglioside sialic acid content of the subcutaneously grown tumour was low (12.6 ± 0.9 μg per 100 mg dry wt, n= 6 separate tumours) and about 70% of this was in the form of N-glycolylneuraminic acid. In contrast, the ganglioside content of the cultured VM tumour cells was high (248.4 ± 4.4 μg, n= 3) and consisted almost exclusively of N-acetylneuraminic acid. The ganglioside pattern of the tumour grown subcutaneously was complex, while GM3, GM2, GM1, and GD1a were the major gangliosides in the cultured tumour cells. This tumour will be a useful natural model for evaluating the role of gangliosides and other glycolipids in tumour cell invasion and metastasis. © 2001 Cancer Research Campaign http://www.bjcancer.co