A Comparative Study of Disulphide-Bonding and Molecular Weights of Purified Fractions from Secalin, Gliadin, and Hordein

Prolamin polypeptides from rye, wheat, and barley were comparedwith respect to the nature of their disulphide bonds, the effectsof reduction, and their molecular weights. Most secalins weredistinguished by their ease of reduction to polypeptides ofintermediate mobility, ranging in size from about 82–92kilodaltons (Kd), or to polypeptides with molecular weightsof 38 Kd that migrated 20–25% slower upon reduction. Athird group of secalin components had intermediate electrophoreticmobility on lactate gels, were unaffected by reducing agentsand had a molecular weight of 48 Kd. Wheat gliadin fractionscontained two types of component: the w-gliadins that couldnot be reduced further and the -, ß-, or -gliadinswhich were reduced to polypeptides of slightly lower electrophoreticmobilities than their native precursors. The predominant molecularweight range of gliadin polypeptides was 33–37 Kd. Thepredominant polypeptide components of hordein were nonreducible,with apparent molecular weights in the range from 50–60Kd. Few secalin or hordein polypeptides were similar in bothsize and reactivity to the gliadins. Key words: Secalin, Hordein, Gliadin, Molecular weight, Disulphide bond     

Intraspecies Variability in the Esterases and Acid Phosphatases of Paramecium jenningsi and Paramecium multimicronucleatum: Assignment of Unidentified Paramecia; Comparison with the P. aurelia Complex1

ABSTRACT. Enzyme electrophoresis was exploited to identify stocks of paramecia previously not identified to particular species. Stocks collected in India and one from Panama belong to Paramecium jenningsi, while others collected in Panama or in Brazil are assignable to syngen 2 of P. multimicronucleatum on the basis of similarity of their esterase and acid phosphatase phenotypes. Inclusion of these doubled the numbers of stocks available in the two species, thereby facilitating examination of intraspecies variation and comparison of particular features of intraspecies variation found for the P. aurelia complex. Variant stocks were observed in P. jenningsi and in syngens 2, 3, and 4 of P. multimicronucleatum. In some cases the variant lacked the enzyme; in others, a change in mobility of the enzyme occurred that resulted in an electrophoretic form similar to one common in another species. Unique phenotypes were displayed by the variants of syngen 2 in P. multimicronucleatum. Hypervariability for Esterase B was observed in this syngen, where, in addition, several subtypes were seen for three other esterases. Unique phenotypes and hypervariability were also noted in P. biaurelia. Clustered variations were observed in these species and in the P. aurelia species. Unlike the situation for members of the aurelia complex, where lack of geographical differentiation between stocks in the same species is a unique feature, some such differentiation does occur in P. multimicronucleatum-2. The frequency of variant stocks in P. jenningsi was similar to that observed in the aurelia sibling species. In contrast, a significantly higher frequency of variant stocks was found in syngens 2, 3, and 4 of P. multimicronucleatum.     

INTERACTIONS OF 1-METHYLADENINE AND THE SURFACE OF STARFISH OOCYTE

Three metabolic inhibitors, mycostatin, concanavalin A (Con A) and cytochalasin B (CB) were used to study the interactions between l-methyladenine (1-MA) and the starfish oocyte surface leading to germinal vesicle breakdown (GVB). Mycostatin and Con A had no obvious effects on GVB. CB did not inhibit, but did delay GVB. This delaying effect was interpreted as having multiple 1-MA reactive "sites" on the surface. The results also suggested that not all of them were needed to react with 1-MA to bring about GVB.     

Blood Parasites of Taiwan Birds*

SYNOPSIS. Blood films were examined from 1477 birds of Taiwan (193 species, 49 families). Haemoproteus Kruse was by far the commonest parasite, with Leucocytozoon Danilewski a not very close second. It is probable that some of the Haemoproteus infections represented new species, and 1 occurring in the Bamboo Partridge (Bambusicola thoracica sonorivox Gould) seemed characteristic enough to justify recognition as such; the name Haemoproteus bambusicolae sp. n. is proposed for this organism. Malaria was found in 77 birds, the greatest number of infections occurring in the Bamboo Partridge. Most of them were caused by Plasmodium juxtanucleare Versiani & Gomes, a pathogen of chickens, but a number were due to an undetermined species of Plasmodium. The Bamboo Partridge may be a reservoir host of the former. A few other identified species (P. rouxi Sergent & Sergent, P. hexamerium Huff, P. tenue Laveran & Mesnil) were seen, as well as some unidentified ones. Plasmodium tenue was seen in Garrulax canorus taewanus Swinhoe, a babbler: until now it was known only from the Pekin Robin (Leiothrix luteus Scopoli), also a babbler, in which we have found it extremely common. Sixty-four microfilarial infections were identified; they were especially frequent in the Button Quail (Turnix suscitator rostrata Swinhoe).     

Degradation of Paramylon by Euglena gracilis

SYNOPSIS. Protozoa of the order Euglenida contain a polysaccharide storage product, paramylon, composed of 1, 3-linked glucose molecules arranged into an extremely resistant granule. An enzyme was purified from the soluble phase of Euglena gracilis which would degrade this polysaccharide to single glucose residues, providing the integrity of the paramylon granule was 1st disrupted by dilute base. This enzyme, a β-1, 3 glucanase, had optimal activity at pH 5.0 and 60 C and bound tightly to base-disrupted paramylon substrate tho not to the intact granules. The specific activity of the enzyme was doubled when cell cultures reached stationary phase, the phase where net carbohydrate utilization began. An ATP-dependent hexokinase reaction was also present in Euglena homogenate. No phosphorylase activity has been found in Euglena. It is suggested, therefore, that Euglena do utilize their paramylon as a carbohydrate reserve and the mechanism of this utilization is by exo-hydrolytic cleavage to free glucose followed by phosphorylation and glycolysis.     

THE CHARACTERS OF SOME COLIFORM BACTERIA ISOLATED FROM GRASS AND GRASS SILAGE

The species of coliform bacterium predominant on fresh grass was found to be a capsulated type growing well at 30^o C. but unable to grow at 37^o C. For this reason it will not be detected by the presumptive test in bile salt-lactose broth at 37^o C. The name Bacillus (Aerebacter) aerogenes graminis is proposed for this species.
It is possible that conforms of the above type contribute to a small extent to the initial fermentation of the silage. Those coliforms giving the presumptive test at 37^o C. were found in such small numbers in the silage investigated that their influence was concluded to be negligible.
This work forms part of some research carried out under grant from the Research Council of Imperial Chemical Industries, Ltd., to whom the authors wish to make due acknowledgement. Valuable help was also received from Dr S. J. Watson, who supplied samples of grass and silage-     

Studies on the Mechanism of Action of Estradiol in Regulating Follicular Progesterone Levels: Effects on cAMP Mediated Events and 3β-Hydroxysteroid Dehydrogenase

Previous studies demonstrated that estradiol interferes with pituitary-induced progesterone production and oocyte maturation in cultured amphibian ( Rana pipiens ) ovarian follicles. To elucidate the mode of action of estradiol in modulating follicular progesterone accumulation we have examined its effects on cAMP-induced progesterone production and enzymatic conversion of pregnenolone to progesterone by 3β-hydroxysteroid dehydrogenase (3β-HSD). Follicular cAMP levels were manipulated with forskolin (an adenylate cyclase activator), isobutyl methyl xanthine (IBMX-phosphodiesterase inhibitor) and exogenously added cAMP. Progesterone production induced by forskolin alone or forskolin in combination with frog pituitary homogenate (FPH) was inhibited by estrogen. Addition of estradiol to culture medium markedly inhibited follicular progesterone accumulation following treatment of follicles with cAMP and IBMX. In the presence of exogenous pregnenolone, non-FPH stimulated ovarian follicles effectively converted the 3β-HSD substrate to progesterone. Treatment of follicles with estradiol inhibited conversion of pregnenolone to progesterone. The results indicate that estradiol acts, following FPH stimulation, at one or more steps subsequent to elevation of cAMP levels to regulate intrafollicular progesterone accumulation and oocyte maturation. Estrogen appears to directly influence the enzymatic (3β-HSD) conversion of pregnenolone to progesterone.