Effect of adsorption of an inhibitory factor on raw starch hydrolysis by glucoamylase

An inhibitory factor (IF) produced byAspergillus niger strain 19, and which inhibits the action of glucoamylase on starch, has the ability to be tightly adsorbed on to various raw starches, though the amount differs from starch to starch. Based on the hydrolysis of the IF-starch complex by glucoamylase, the inhibitions per unit IF adsorbed are similar for some varieties of starch. The effectiveness ratio of IF (% hydrolysis inhibition per % IF adsorbed on raw starch) for corn, sweet potato, waxy rice and waxy corn starches are 1.1, 1.0, 0.85 and 0.96, respectively. These results support the hypothesis that both glucoamylase and IF are adsorbed on to a common binding site on raw starch. However, the effectiveness ratio of IF for cassava and wheat starches are 0.71 and 1.65, respectively, which differ significantly from other varieties of starch.

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Résumé Un inhibiteur (facieur IF) produit par la souche 19 d'Aspergillus niger et qui inhibe l'action de la glucoamylase sur l'amidon a la propriété d'être fortement adsorbé sur dives amidons, bien que la quantité varie d'amidon à amidon. Sur la base de l'hydrolyse du complexe amidon-IF par la glucoamylase, les inhibitions par unité d'IF adsorbé sont sembiables pour quelques variétés d'amidon. Le rapport d'efficience de IF (% d'inhibition de l'hydrolyse par % de IF adsorbé sur l'amidon cru), pour le maïs, la patate douce, et les amidons de riz cireux et de maîs cireux vaut respectivement 1.1, 1.0, 0.85 et 0.96. Ces résultats soutiennent l'hypothèse que tant la glucoamylase que le lacteur IF sont adsorbés sur un site commun de liaison de l'amidon cru. Toutefois, le rapport d'efficience du facteur IF pour les amidons de manioc et de froment valent respectivement 0.71 et 1.65, valeurs significativement différentes de celles pour les aufres variétés d'amidon.

     

Some characteristics of a raw starch digestion inhibitory factor fromAspergillus niger

Summary The effect of an inhibitory factor (IF) fromAspergillus niger 19 on raw starch digestion by pure glucoamylase I of blackAspergillus, pure glucoamylae ofRhizopus niveus, bacterial -amylase, fungal -amylase and various combination was investigated. The IF caused higher inhibition of raw starch hydrolysis by the combined action of glucoamylase and fungal -amylase than of hydrolysis by the individual enzymes. A protein moiety of IF might play an active part in this inhibition phenomenon. The IF was bound to starch granules, preventing hydrolysis by the enzymes, and caused decreased raw starch hydrolysis yields.     

Vasoactive intestinal peptide stimulates ciliary motility in rabbit tracheal epithelium: modulation by neutral endopeptidase.

We studied the effect of vasoactive intestinal peptide (VIP) on ciliary activity in rabbit cultured tracheal epithelium by a photoelectric method in vitro. Administration of VIP (10(-7) M) elicited an increase in ciliary beat frequency (CBF) from the baseline values of 970 +/- 52 to 1139 +/- 75 beats/min (mean +/- S.E., P less than 0.01). This ciliostimulatory effect was dose-dependent, with the maximal increase and EC50 value being 17.4 +/- 1.0% (P less than 0.05) and 6.10(-11) M, respectively. The VIP-induced increase in CBF was abolished by pretreatment of cells with [4-Cl-D-Phe6, Leu17]-VIP, a VIP receptor antagonist. The neutral endopeptidase inhibitor phosphoramidon (10(-5) M) potentiated the effect of VIP, so that the CBF dose-response curve for VIP was shifted to lower concentrations by 0.5 log U. The administration of VIP increased cyclic AMP levels in epithelial cells, an effect that was also potentiated by phosphoramidon. These results suggest that VIP may interact with its specific receptors and stimulate airway ciliary activity probably through the activation of adenylate cyclase, and that neutral endopeptidase may play a role in modulating this effect of VIP.     

Altered localization of antigen recognized by proteinuriainducing monoclonal antibody in experimental nephrosis

Change in the localization of the antigen recognized by the proteinuria-inducing monoclonal antibody (MA) 5-1-6 in experimental nephrosis was studied by indirect and biotin-avidin immunofluorescence, and immunoperoxidase at light and electron microscopical levels. The proteinuric state was induced by the administration of the aminonucleoside of puromycin (PAN) or adriamycin. The antigen decreased in quantity and/or its distribution changed with an increase in the amount of protein excreted in both experimental models. Recovery from the alterations observed during the development and proteinuria appeared to occur when PAN-induced proteinuria subsided. This antigenic molecule may thus be essential for maintaining the normal permselectivity of glomerular capillary walls.     

REPRODUCTIVE ISOLATION AND DISTINCT POPULATION STRUCTURES IN TWO TYPES OF THE FRESHWATER SHRIMP PALAEMON PAUCIDENS

Twenty local populations of the Japanese freshwater shrimp Palaemon paucidens were electrophoretically and morphologically surveyed. Based on the diagnostic distributions of some alleles at Gpi, Mpi, Mdh-1, and Mdh-2, these populations were largely classified into two types (A and B). The A type occurred in lakes, ponds, and rivers, while the B type was observed only in rivers. Average Nei's genetic distance (D) between the two types fell into the subspecies range . The coefficient of gene differentiation, G_ST, varied considerably between the two types. In 12 populations of the A type, with a G_ST value of 0.281, nine pond and lake populations showed a higher G_ST (0.246) than the three river populations (0.151). On the other hand, G_ST was 0.036 for the eight local populations of the B type. The lower rostrum tooth number had a mode of two in type A and three in type B. Type-A populations largely varied in the upper rostrum tooth number and egg size but type B did not. Under laboratory conditions, mating frequently occurred within each type, but not between types. Furthermore, no embryonic development was observed in the few cases of intertype mating. These results indicate that the A and B types had experienced cladogenic separation with pre- or postmating isolation, whereafter the A type, under geographic isolation, underwent genetic and phenotypic differentiation, while the B type, under extensive gene flow, did not undergo differentiation.     

Human atrial natriuretic polypeptide in plasma of patients with anorexia nervosa

To examine the effects of chronic dehydration and starvation on plasma levels of human atrial natriuretic polypeptide (hANP) in human subjects, the basal level and saline-induced rise of plasma hANP in 7 patients with anorexia nervosa were compared with those in age-matched healthy subjects. The unstimulated level of plasma hANP was markedly high in the patients with anorexia nervosa (patients vs. control; 55.4 +/- 9.0 pg/ml vs. 11.4 +/- 6.1 pg/ml, P less than 0.01). However, no significant increase of plasma hANP in the anorectic patients was observed in response to saline-infusion, while a 3-fold increase over the basal level of plasma hANP was noted in the saline-infused normal young subjects. These results show that hANP may be secreted to an inadequate extent, hence the release would be resistant to volume-loading. The pathophysiological meaning of such a high plasma concentrations of hANP in anorexia nervosa is the subject of ongoing studies.     

Fine structural and immunohistochemical studies of goat adenohypophysial cells

Summary The fine structure of each type of anterior pituitary cell in the male goat was studied through the application of a superimposition technique in which adjacent thick sections were used to identify individual cells beforehand by light-microscopic immunohistochemistry. A cone of the pars intermedia protrudes into the pars anterior, being surrounded by the narrow pituitary cleft; the immunohistochemical appearances of the cells forming the cone resemble those of the pars anterior. Several follicles appear in the pars anterior. Ultrastructurally GH cells resemble prolactin cells. The secretory granules of both types are spherical; the diameter of the former is about 340 nm, whereas that of the latter is about 440 nm. ACTH cells are polygonal in shape with secretory granules, about 180 nm in diameter, scattered throughout the cytoplasm. TSH cells, which are spherical in shape, contain the smallest secretory granules, 150 nm in diameter. The highly electron-dense LH cells contain numerous secretory granules about 210 nm in diameter. Their nuclei are irregular with incisures. Thus, the anterior pituitary cells of the goat are ultrastructurally characteristic and species-specific.     

Studies on extracellular ribonucleases of Ustilago sphaerogena. Purification and properties

1. Four ribonucleases were isolated from culture media of Ustilago sphaerogena. They were designated ribonucleases U(1), U(2), U(3) and U(4). 2. They were purified about 1600-, 3700-, 1100- and 16-fold respectively. 3. It was shown by gel filtration that ribonucleases U(1), U(2) and U(3) have molecular weights about 10000 like ribonuclease T(1), and that ribonuclease U(4) is much larger. 4. Ribonucleases U(1), U(2) and U(3) are thermostable, but ribonuclease U(4) is not. 5. The pH optimum of ribonucleases U(1) and U(4) is pH8.0-8.5, and that of ribonucleases U(2) and U(3) is pH4.5.