A new peptide coupling agent — phosphonitrilic chloride

Zusammenfassung Phosphonitrilchlorid, dessen Verbindung razemisierungsfrei erfolgt, kann als Reagens zur Synthese von Peptiden verwendet werden.     

Freezing and transplantation of brain tissue in rats

Summary Neocortical tissue obtained from rat embryos was frozen and stored at –70°C for 6 h prior to transplantation into the cerebellum of neonatal rats. Growth, differentiation, and integration of this tissue within the host brain was comparable to that obtained from freshly dissected and transplanted tissue. It is suggested that freezing to low temperatures does not adversely effect the viability or transplantability of the neural tissue.Supported by N.I.H. research grants Nos NS-08817 and CA-14650.     

Neuroscience: rewiring the adult brain

Any analysis of plastic reorganization at a neuronal locus needs a veridical measure of changes in the functional output--that is, spiking responses of the neurons in question. In a study of the effect of retinal lesions on adult primary visual cortex (V1), Smirnakis et al. propose that there is no cortical reorganization. Their results are based, however, on BOLD (blood-oxygen-level-dependent) fMRI (functional magnetic resonance imaging), which provides an unreliable gauge of spiking activity. We therefore question their criterion for lack of plasticity, particularly in the light of the large body of earlier work that demonstrates cortical plasticity.     

Biochemical changes of muscle proteins in goldfish (Carassius auratus) during thermal acclimatization

Zusammenfassung Kälteadaptierte Goldfische (Carassius auratus) bauen mehr Leuzin in Muskelproteine ein, wobei die Steigerung in verschiedenen Muskeleiweissfraktionen gleich ist. Aus kälteadaptierten Goldfischmuskeln ist mehr Myosin und sarkoplasmisches Eiweiss extrahierbar.     

The crystal structure of murrayazoline (Mahanimbidine,curryangin)

Riassunto La struttura del murrayazoline, un'alcoloide carbazole, é stata confermata per via cristallografica con i raggi X.     

Electron impact studies iv. Expulsion of methylene under electron impact

Zusammenfassung Es wird gezeigt, dass bei geeigneten Verbindungen die Ausstossung der Methylengruppe im Massenspektrum eine bevorzugte Reaktionsweise darstellt. Diese Reaktionsweise gleicht derjenigen der Abgabe von Kohlenmonoxyd aus cyclischen Ketonen oder Chinonen.     

A 41, XYY mouse

Summary Cytogenetic analyses of bone marrow and meiotic cells in an apparently normal male mouse clearly revealed the presence of an extra Y chromosome leading to 2n=41, XYY. During meiosis the sex chromosomes formed all possible types of combinations (XYY, XY/Y, YY/X and X/Y/Y). Compared to 40, XY normal mice, the sperm count was significantly less, but the incidence of sperm head abnormality was at the normal level.Acknowledgment. The authors are grateful to Prof. G. K. Manna, Department of Zoology, Kalyani University, for his valuable comments and Prof. M. C. Dash, School of Life Sciences, Sambalpur University for providing necessary facilities. Thankful acknowledgment to CSIR, India for a SRF awarded to RNK.     

Thermodynamics of bromate and iodate of sodium in dioxane-water mixtures at different temperatures

Summary The free energy transfer (G _t ⁰ ) enthalpy of transfer (H _t ⁰ ) and entropy of transfer (S _t ⁰ ) of NaBrO₃ and NaIO₃ from water to 10, 20 and 30% dioxane-water mixtures have been studied using conductance measurements. The chemical and electrical parts of these transfers of thermodynamic parameters have been estimated.To whom reprint requests should be addressed.     

Tannic acid inhibits insulin-stimulated lipogenesis in rat adipose tissue and insulin receptor function in vitro

Tannins occur naturally in relatively abundant amounts in fruits, herbal medicines and common beverages. Thus an understanding of how these polyphenols affect peptide hormone action is of importance. We report here that tannic acid (a hydrolysable tannin) inhibits insulin-stimulated lipogenesis in rat adipose tissue in vitro, with an IC₅₀ estimated to be about 350 M. However, its monomer, gallic acid, did not show a similar inhibitory effect at concentrations up to 1 mM. The inhibition by tannic acid was less evident with higher concentrations of bovine serum albumin in the incubation buffer. This was attributed to the formation of a tannin-protein complex between bovine serum albumin and tannic acid. In a binding assay, it was observed that the specific binding of insulin to its receptor was not inhibited by tannic acid in the concentration range 0–200 M. However, insulin-stimulated autophosphorylation of the insulin receptor, and receptor-associated tyrosine kinase phosphorylation of RR-SRC peptide, were inhibited by tannic acid at concentrations as low as 25 M. Our data do not support the current speculation that tannins affect the activity of peptide hormones by binding to them. Therefore, our finding opens up a new perspective in the understanding of the mode of action of tannins on such hormones.