Regulation of rat hepatic stearoyl coenzyme A desaturase. The roles of insulin and carbohydrate.

The rat hepatic stearoyl-CoA desaturation decreased by 3.7-fold in streptozotocin-induced diabetes. Insulin treatment of diabetic rats increased the enzyme activity by 7-fold. In marked contrast to glucose administration, fructose feeding in diabetic rats resulted in 20-fold stimulation of stearoyl-CoA desaturation, although both carbohydrates stimulated stearoyl-CoA desaturation in normal rats. Measurement of the microsomal electron transfer components showed no significant changes in the NADH-cytochrome b5 reductase activity or in the concentration of cytochrome b5. However, the activity of the terminal desaturase changed in a parallel fashion as the amount of terminal desaturase reflect changes in the overall desaturation. Supplementation of various microsomes with the saturating amount of purified terminal desaturase resulted in the formation of similar amounts of catalytically active complex and increased the stearoyl-CoA desaturation to the same level suggesting that the changes in the amount of terminal desaturase reflect changes in the overall desaturation. The results support the suggestion that both insulin and the intermediates of carbohydrate metabolism are involved in the regulation of terminal desaturase.     

Light microscopic features of the rete testis,the vas efferens,the epididymis and the vas deferens in the adult rhesus monkey

The present study was carried out to determine the detailed histological and cytological features of the excurrent ducts of the male reproductive system in the rhesus monkey. The excurrent ducts show a regional difference in their histological features. The use of some of these features as histological markers and their possible functional significance are discussed. The epithelial cells in the different components of the excurrent duct system possess cytological features which suggest their involvement in absorption and the secretion of different products into the lumen.     

Mitotic factors from mammalian cells: A preliminary characterization

The objective of this study was the preliminary characterization of the factors from mitotic HeLa cells that can induce meiotic maturation in Xenopus laevis oocytes. We found that this factor is a heat-labile, Ca²⁺-sensitive, nondialyzable protein with a sedimentation value of 4-5S. Furthermore, no new protein synthesis was found to be required for this mitotic factor to induce maturation in the amphibian oocytes. These data suggest that the factors involved in the breakdown of nuclear membrane and the condensation of chromosomes that are associated with three different phenomena, mitosis, meiosis, and premature chromosome condensation, are very similar in different animal species.     

Relative efficiency of rock phosphate and superphosphate for cowpea (Vigna sinensis Savi) fodder

Summary Cowpea responded well to phosphorus and P application increased green-fodder production and P uptake. With respect to green-fodder production, the rock phosphate was found to be 50–55% as effective as superphosphate. Phosphorus when applied at 50 kg P₂O₅/ha as superphosphate or rock phosphate almost doubled the P uptake by the summer-season crop of cowpea as compared to no phosphorus control. The residual effect did not differ significantly on succeeding rainy-season crop of cowpea. Application of starter N increased the total green-fodder yield of two crops by 38 q/ha. re]19750710     

Effect of sodium butyrate on mammalian cells in culture: a review.

Sodium butyrate produces reversible changes in morphology, growth rate, and enzyme activities of several mammalian cell types in culture. Some of these changes are similar to those produced by agents which increase the intracellular level of adenosine 3',5'-cyclic monophosphate (cAMP) or by analogs of cAMP. Sodium butyrate increases the intracellular level of cAMP by about two fold in neuroblastoma cells; therefore, some of the effects of sodium butyrate on these cells may in part be mediated by cAMP. Sodium butyrate appears to have properties of a good chemotherapeutic agent for neuroblastoma tumors because the treatment of neuroblastoma cells in culture causes cell death and "differentiation"; however, it is either innocuous or produces reversible morphological and biochemical alterations in other cell types.     

Initiation of ovalbumin synthesis in chicken oviduct magnum: Transient labeling of the NH2-terminus by methionine

The incorporation of [³⁵S]methionine into ovalbumin, a protein containing NH₂-terminal N-acetylglycine, has been studied in chicken oviduct magnum cells. The purification of [³⁵S]methionine-labeled ovalbumin from total oviduct proteins was accomplished by dialysis of a crude extract at pH 3.6 followed by chromatography on carboxymethyl cellulose. The radioactive ovalbumin eluted from the column in three peaks (P₀, P₁, and P₂-containing 0, 1, and 2 moles of phosphate, respectively, per mole of ovalbumin). The kinetics of labeling of peaks P₀ and P₁ showed that the ratio of radioactivity in NH₂-terminal methionine to total incorporation was greater at 2 min of labeling than at later times. The transient labeling of the NH₂-terminus of ovalbumin with methionine indicates that methionine is the initiator amino acid for the synthesis of this protein, which in its mature form contains NH₂-terminal N-acetylglycine.     

Laboratory evaluation of a carabid larva,Chlaenius bioculatus [Col.: Carabidae] as a predator of lepidopterous pests

Food preference as well as feeding efficiency studies of the carabid predator revealed that the grub of theChlaenius bioculatus Chaud preferred mostPolytella gloriosae F. larvae in both 2nd and 3rd instar.Tarache tropica Guénée was preferred least by the grub predator in both instar.T. tropica was found toxic and grubs of the predator died after consumption.

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Résumé Les préférences alimentaires, de même que l'efficacité prédatrice deChlaenius bioculatus Chaud, montrent que ce carabide prédateur préfère le plus les larves dePolytella gloriosae F. du 2^e et 3^e stade.Tarache tropica Guénée est le moins attaqué aux deux stades.T. tropica est toxique et les larves du prédateur meurent après sa consommation.

     

Effect of sodium butyrate on mammalian cells in culture: A review

Summary Sodium butyrate produces reversible changes in morphology, growth rate, and enzyme activities of several mammalian cell types in culture. Some of these changes are similar to those produced by agents which increase the intracellular level of adenosine 3′,5′-cyclic monophosphate (cAMP) or by analogs of cAMP. Sodium butyrate increases the intracellular level of cAMP by about two fold in neuroblastoma cells; therefore, some of the effects of sodium butyrate on these cells may in part be mediated by cAMP. Sodium butyrate appears to have properties of a good chemotherapeutic agent for neuroblastoma tumors because the treatment of neuroblastoma cells in culture causes cell death and “differentiation”; however, it is either innocuous or produces reversible morphological and biochemical alterations in other cell types.     

Simian virus 40 integration sites in the genome of virus-transformed mouse cells.

To gain information on the specificity of simian virus 40 (SV40) integration in the genome of transformed cells, mouse 3T3 cells were transformed by a temperature-sensitive (ts) SV40 mutant, using high multiplicity of infection (MOI). Transformed cells were superinfected with wild-type (wt) virus at high MOI. Clones were isolated and fused with permissive BSC-1 cells to promote virus rescue. All rescued viruses were of the ts type only. When the high-MOI transformants were infected with 3H-labeled wt SV40, the amount of radioactivity associated with their nuclear fraction was found to be similar to that of 3T3 cells. 3T3 cells were then transformed by ts SV40 at low MOI and superinfected by wt virus at high MOI. Upon fusion with BSC-1 cells, most clones produced both ts and wt virus. These results suggest that the number of stable SV40 integration sites in the 3T3 genome is limited, since they can be saturated by transformation at high MOI. When the MOI is low, the sites are not saturated and a subsequent infection can lead to integration.     

Cyclin D1 and cyclin D3 show divergent responses to distinct mitogenic stimulation

D‐type cyclins predominantly regulate progression through the cell cycle by their interactions with cyclin‐dependent kinases (cdks). Here, we show that stimulating mitogenesis of Swiss 3T3 cells with phorbol esters or forskolin can induce divergent responses in the expression levels, localization and activation state of cyclin D1 and cyclin D3. Phorbol ester‐mediated protein kinase C stimulation induces S phase entry which is dependent on MAPK activation and increases the levels and activation of cyclin D1, whereas forskolin‐mediated cAMP‐dependent protein kinase A stimulation induces mitogenesis that is independent of MAPK, but dependent upon mTor and specifically increases the level and activation of cyclin D3. These findings uncover additional levels of complexity in the regulation of the cell cycle at the level of the D‐type cyclins and thus may have important therapeutic implications in cancers where specific D‐cyclins are overexpressed. J. Cell. Physiol. 225: 638–645, 2010. © 2010 Wiley‐Liss, Inc.