Biomass protein formation by filamentous fungi on woody substrates

Summary Growth and biomass protein formation by filamentous fungi grown on pretreated tropical woods of Mesta (Hibiscus cannabinus Linn.) and Subabul [Leucaena leucocephala (Lam.) de Witt] as well as their isolated hemicellulose and cellulose fractions have been studied. Penicillium janthinellum and Penicillium funiculosum produced a biomass having 20 to 30% crude protein when grown on either hemicellulose, while growth on pretreated (autoclaved in 1% NaOH) wood or isolated cellulose fractions was comparatively poor and crude protein content only 5 to 8% in the biomass.NCL Communication no.3550     

Occurrence of a procellulase in the culture filtrates of Penicillium janthinellum

The endo-1,4-β-d-glucanase [cellulase, 1,4-(1,3:1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] activity of two-day old culture filtrates of Penicillium janthinellum has been enhanced four-fold by incubating with a 10-day old culture filtrate of Penicillium funiculosum grown on the same medium. An inactive protein isolated by fractionation of two-day old culture filtrate of P. janthinellum using preparative isoelectric focusing, showed 30- to 50-fold enhancement of endo-1,4-β-d-glucanase activity. This fraction has been designated the ‘procellulase’ in the present paper. The purity of the procellulase was confirmed by analytical isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. It had a molecular weight of 68 000 and an isoelectric point of pH 3.7.     

Theoretical studies on the modes of binding of some of the derivatives of d-mannose to concanavalin A

The possible modes of binding for $\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$, $\text{methyl}\text{-β-}\text{d}\text{-mannopyranoside}$, $\text{2-O-}\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$, $\text{methyl-2-O-methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ and $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$ to concanavalin A have been investigated using theoretical methods. All these sugars, except $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$, reach the active site of concanavalin A with a highly restricted number of binding orientations. Present investigations suggest that the failure of $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$ to bind to concanavalin A is not so much due to steric factors as to repulsive electrostatic interactions. $\text{Methyl}\text{-2-O-}\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ can bind to concanavalin A in one mode whereas the other sugars can bind in more than one mode. The high potency of $\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ over $\text{methyl}\text{-β-}\text{d}\text{-mannopyranoside}$ is mainly due to the possibility of hydrophobic interactions of the α-methoxy group with Leu(99) or Tyr(100) and also due to the possibility of formation of better and more hydrogen bonds with the protein. A comparison of these data with those for the d-glucopyranosides suggests that the change of the hydroxyl at the C-2 atom from equatorial to axial orientation increases the stereochemically allowed region as well as the possible binding modes. From these studies it is also suggested that the overall shape of the oligosaccharides rather than the terminal or internal mannose alone affects the binding potency of saccharides to concanavalin A.     

Theoretical studies on the modes of binding of some of the derivatives of d-mannose to concanavalin A

The possible modes of binding for methyl-α-d-mannopyranoside, methyl-β-d-mannopyranoside, 2-O-methyl-α-d-mannopyranoside, methyl-2-O-methyl-α-d-mannopyranoside and methyl-α-d-N-acetylmannosamine to concanavalin A have been investigated using theoretical methods. All these sugars, except methyl-α-d-N-acetylmannosamine, reach the active site of concanavalin A with a highly restricted number of binding orientations. Present investigations suggest that the failure of methyl-α-d-N-acetylmannosamine to bind to concanavalin A is not so much due to steric factors as to repulsive electrostatic interactions. Methyl-2-O-methyl-α-d-mannopyranoside can bind to concanavalin A in one mode whereas the other sugars can bind in more than one mode. The high potency of methyl-α-d-mannopyranoside over methyl-β-d-mannopyranoside is mainly due to the possibility of hydrophobic interactions of the α-methoxy group with Leu(99) or Tyr(100) and also due to the possibility of formation of better and more hydrogen bonds with the protein. A comparison of these data with those for the d-glucopyranosides suggests that the change of the hydroxyl at the C-2 atom from equatorial to axial orientation increases the stereochemically allowed region as well as the possible binding modes. From these studies it is also suggested that the overall shape of the oligosaccharides rather than the terminal or internal mannose alone affects the binding potency of saccharides to concanavalin A.     

Role of ascorbic acid in metabolism of rat testis and epididymis in relation to the onset of puberty

The metabolism of ascorbic acid, cholesterol, serum testosterone level and activities of 3Β and 17Β hydroxysteroid dehydrogenases were studied in testis and Cauda epididymis of prepubertal, pubertal and postpubertal (5, 15, 30, 45, 55 and 60 day old) rats. The data showed that serum testosterone levels and 3Β and 17Β hydroxysteroid dehydrogenases were increased with the age. The ascorbic acid metabolism was found to be stabilized in testis at day 30 being comparable with the adult, whereas a spurt in its metabolism occurred by day 45 and a significant depletion in ascorbic acid content in relation to the passage of the first wave of spermatozoa through cauda epididymis. The results of this study clearly elucidate that ascorbic acid is involved in metabolism of testis and epididymis in developing postnatal rats, in relation to the increasing demands for attaining a stable hormonal milieu, and the onset of puberty and the passage of the first wave of spermatozoa,via the formation of its free radical monodehydroascorbic acid and charge transfer complex mechanism     

Studies on regulation of chorionic gonadotropin secretion in primates

The regulation of secretion of chorionic gonadotropin in primates has been studied using bothin vivo andin vitro models.In vivo studies using the pregnant bonnet monkey revealed that at the doses tested, the administration of progesterone or estradiol 17Β in combination or alone did not result in any appreciable change in the duration or magnitude of serum chorionic gonadotropin levels. However, administration of lutropin-releasing hormone by intravenous route resulted in significant increase in chorionic gonadotropin levels within 30–60 min and the extent of stimulation seemed to depend on the state of pregnancy. Forin vitro studies, explants or cells prepared from first trimester human placenta has been used. The functional integrity of these cells has been established by demonstrating the binding of [¹²⁵I]-labelled human chorionic gonadotropin antibody to the cells as well as the synthesis of [³H]-labelled human chorionic gonadotropin.In vitro studies using the cells revealed that addition of lutropin-releasing hormone caused a significant increase in chorionic gonadotropin and estradiol 17Β secreted into the medium. Thus bothin vivo andin vitro results suggest that lutropin-releasing hormone could be one of the factors involved in regulation of chorionic gonadotropin secretion in primates.     

Studies on the conformations of sialyloligosaccharides and implications

Theoretical investigations, using semi-empirical potential functions have been carried out to predict the favoured conformations of the terminal dissaccharide fragments of various sialyloligosaccharides. The proposed conformational similarity for these fragments has been correlated to the binding specificity of neuraminidases. These calculations predict that bacterial neuraminidases have a binding site which can accommodate only two sugar residues and virus neuraminidases have a binding site which can accommodate more than two sugar residues.     

Kinetic mechanism of the interaction of D-cycloserine with serine hydroxymethyltransferase

The kinetic mechanism for the interaction of D-cycloserine with serine hydroxymethyltransferase (EC 2.1.2.1) from sheep liver was established by measuring changes in the activity, absorbance, and circular dichoism (CD) of the enzyme. The irreversible inhibition of the enzyme was characterized by three detectable steps: an initial rapid step followed by two successive steps with rate constants of 5.4 X 10(-3) s-1 and 1.4 X 10(-4) s-1. The first step was distinguished by a rapid disappearance of the enzyme absorbance peak at 425 nm, a decrease in the enzyme activity to 25% of the uninhibited velocity, and a lowering of the CD intensity at 432 nm to about 65% of the original value. The second step of the interaction was accompanied by a complete loss of enzyme activity and a marginal increase in the CD intensity at 432 nm. The final step resulted in the complete loss of the enzyme absorbance at 425 nm and of the CD band at 432 nm. The products of the reaction were identified as (a) apoenzyme by absorbance measurements, CD spectra, and reconstitution with pyridoxal 5'-phosphate and (b) a pyridoxal 5'-phosphate-D-cycloserine Schiff's base complex identified by its fluorescence and absorbance spectra. The Schiff base complex was expelled from the enzyme active site in the final step of the reaction. The proposed mechanism, which is different from those operative in other pyridoxal phosphate dependent enzymes, probably accounts for the selective inhibition of serine hydroxymethyltransferase by the drug in vivo.     

Commingling in the distributions of fat-related measures in Punjabi families

The distribution of anthropometric measurements related to fatness levels is examined to determine if skewness alone accounts for the nonnormality of such measures. A mixture of two normal distributions or a single skewed distribution fit the data significantly better than a single normal in all cases. For maximum hip width, knee diameter, and weight, two skewed distributions give a better fit than one skewed distribution, rejecting the null hypothesis of a single distribution even when skewness is considered. There is evidence for three skewed component distributions for biceps skinfold. Abdomen circumference, upper arm circumference, triceps skinfold, and calf skinfold are best approximated by a one component log-normal distribution. Children and parents show slightly different patterns in skewness and kurtosis when considered separately, but differences between them do not account for the commingling found in the combined distributions.