Effect of phytic acid on diamine oxidase activity in germinating pea seeds

Summary Diamine oxidase present in the cotyledons of germinating pea seeds is induced by phytic acid but the embryo enzyme is not affected. Polyamines have no effect on phytase activity of the cotyledon or embryo.We thank Dr S. K. Srivastava for his helpful suggestions.     

Effect of phytic acid on diamine oxidase activity in germinating pea seeds.

Diamine oxidase present in the cotyledons of germinating pea seeds is induced by phytic acid but the embryo enzyme is not affected. Polyamines have no effect on phytase activity of the cotyledon or embryo.     

Agmatine iminohydrolase activity during development and germination of groundnut seeds

Summary During the development of groundnut seeds agmatine iminohydrolase activity increased in the cotyledons but remained constant in the embryo. In seeds stored for 1 year, decreased activity of the enzyme was found in both cotyledons and embryo. During germination, the enzyme activity increased in the cotyledons, but in the embryo it increased up to day 3 and then decreased to the initial level.Acknowledgments. This work was supported by grants from the University Grants Commission under the DSA programme. We thank Dr S.K. Srivastava for his helpful suggestions and giving us access to his facilities.     

Effect of various factors on the activity of trehalase from the larvae ofSesamia inferens walker (Insecta)

Summary Trehalase from the salivary glands and the midgut ofSesamia inferens showed optimum activity at pH 5.8, and at temperatures of 50 and 60°C respectively. The increase in the incubation period, enzyme concentration, and substrate concentration respectively increased the end-product, the hydrolysis, and the rate of hydrolysis of the substrate. Dialysis did not affect, tryptophan accelerated, and other amino acids and end-product inhibited the enzyme activity.The author wishes to express his thanks to ProfessorR. Rakshpal for his constructive criticism, and to University Grants Commission, India, for awarding a Junior Research Fellowship.     

Timing of action of sperm proteases in ascidian fertilization

Summary The timing of action of three sperm proteases, acrosin, spermosin, and a chymotrypsin-like enzyme, in the fertilization of the ascidian,Halocynthia roretzi, was examined by adding specific protease inhibitors at various times after insemination. The results indicate that the last two enzymes both function at the early stage of the process of sperm penetration through the egg investment, while acrosin functions at the late stage.Acknowledgments. We are indebted to Dr M. Hoshi of Tokyo Institute of Technology for his helpful discussion, and to Dr T. Someno of Nippon Kayaku Kogyo Co. for his generous gifts of Z-Val-Pro-Arg-H and leupeptin. This work was supported by Grants-in-Aid from the Ministry of Education, Science and Culture of Japan, and from Naito Research Foundation.     

Über die Aktivität der Tyrosinase in Tabaksamen

Summary Water or buffered extracts from tobacco seeds (Mont Calme brun) showed both cresolase and catecholase activity of tyrosinase, which was inhibited by 10^–2 M thiourea. No difference of activity could be observed in extracts from old and fresh seeds. Unexpectedly, chlorogenic acid is not oxidized by this tyrosinase.     

Effect of hormones on adenyl cyclase activity of rabbit mammary gland in vitro

Summary Ovarian hormones namely-estradiol and progesterone were observed to stimulate the activity of adenyl cyclase of the mammary gland from pregnant rabbit in vitro, unlike the lactating tissue where it was inhibited. On the other hand, non-ovarian hormones like hydrocortisone, prolactin and insulin did not have a similar effect on this enzyme.Acknowledgement. We are indebted to Dr D. Sundaresan, for his kind encouragement in this study.     

Some properties of cholinesterase of the plant nematodeAphelenchoides ritzema-boosi

Summary Activity and properties of cholinesterase fromAphelenchoides ritzema-boosi, a plant feeding nematode, were investigated by testing the reaction of the enzyme with different substrates and inhibitors. Butyrylthiocholine was a better substrate than propionyl- and acetylthiocholine. When compared with mammalian erythrocyte and plasma cholinesterase, the nematode enzyme was found to be extremely insensitive towards a number of well-known organophosphorus and carbamate inhibitors.     

Effect of acrylonitrile on trehalase,phosphorylase and acetylcholinesterase activities inTribolium castaneum Herbst andTrogoderma granarium Everts

Summary Acrylonitrile inhibited trehalase and phosphorylases in larvae and adults ofTribolium castaneum. InTrogoderma granarium larvae phosphorylases alone were inhibited. Acetylcholinesterase was not affected.Acknowledgments. We thank Dr R. Radhakrishnamurthy for his suggestions.     

Effect of lectins from leguminous seeds on rat duodenal enterokinase activity

Summary Enterokinase activity from rat duodenal brush borders was assayed in vitro in the presence of purified lectins from 3 leguminous seeds. Noncompetitive inhibition of the enzyme was observed in each case.Phaseolus hemagglutinin was the most potent inhibitor among the 3 lectins tested.     

Newton's Contribution to the Science of Heat

The contents of Scala Graduum Caloris are described, supplemented by unpublished material. Both temperature measurements by his linseed oil thermometer and those based upon his law of cooling are shown to be reasonably accurate to 300°C, but above that value they are much too low. The apparent agreement and the deviation are explained by the differences between the assumptions that Newton made in deriving his law of cooling and the conditions in which he used it. Newton's attempts to link terrestrial and celestial science in applications in the Principia are shown to fail from his confounding the concepts of temperature, heat and radiant intensity and his ignorance of most factors affecting the temperature rise of irradiated materials. Other comments on varied aspects of heat, mainly published in the Queries, are set out and analysed. His originality is assessed.     

The effects of legume seed extracts on plant virus infection

Summary Extracts from the seeds of 15 species of legume inhibited the infection of plants by viruses. Extracts could be divided into those with marked inhibitory activity reducible on heating and those with less marked inhibitory activity which increased on heating. Evidence is given to suggest that seed extracts contain both virus inhibitors and augmenters and that the inhibitors are high molecular weight proteins possibly related to lectins.     

The effects of legume seed extracts on plant virus infection

Extracts from the seeds of 15 species of legume inhibited the infection of plants by viruses. Extracts could be divided into those with marked inhibitory activity reducible on heating and those with less marked inhibitory activity which increased on heating. Evidence is given is given to suggest that seed extracts contain both virus inhibitors and augmenters and that the inhibitors are high molecular weight proteins possibly related to lectins.     

‘Land-marks of the universe’: John Herschel against the background of positional astronomy

John Herschel (1792–1871) was the leading British natural philosopher of the nineteenth century, widely known and regarded for his work in philosophy, optics and chemistry as well as his important research and popular publications on astronomy. To date, however, there exists no extended treatment of his astronomical career. This paper, part of a larger study exploring Herschel's contributions to astronomy, examines his work in the context of positional astronomy, the dominant form of astronomical practice throughout his lifetime. Herschel, who did not himself practice positional astronomy and who was known for his non-meridional observations of specific stellar objects, was nonetheless a strong advocate for positional astronomy—but for very different reasons than the terrestrial applications to which it was most often put. For Herschel, the star catalogues of positional astronomy were the necessary observational foundation upon which information about the stars as physical objects could be constructed. Positional astronomy practiced in the great national observatories was not about navigation or timekeeping; it was a way to standardize stellar observations and make them useful data for constructing theories of the stars themselves. For Herschel, the seeds of the new astronomy emerged from the practices of the old.     

On the inhibitory action of endosperm on germination ofCercis siliquastrum seeds

Summary The endosperm inhibits the growth of embryos isolated fromCercis siliquastrum seeds. The inhibitory activity is present in autoclaved homogenates as well as in homogenates remaining after an extraction with chloroform or isobutanol.Acknowledgment. The authors wish to thank Prof. E. Marré, Milan University, for his help in preparation of this paper.     

Protease in ascidian endostyle

Summary A proteolytic activity at pH 7.6 was determined in the endostyle of the ascidianStyela plicata. With the use of specific inhibitors, it was demonstrated that a tryptic-like alkaline protease, TLCK-dependent, is involved.The author wishes to thank Prof. A Minganti for his critical revision of the text.     

Isolation of isoflavonoid phytoalexins from seeds ofPhaseolus vulgaris L.

Summary Bean seeds challenged withRhizoctonia solani or exposed to natural microflora yielded the isoflavonoid phytoalexins: phaseollin, phaseollidin, phaseollinisoflavan, coumestrol and kievitone. The data suggest that seeds may have the major host-defence factors of a plant.The author thanks Dr Suresh S. Patil of University of Hawaii for his guidance and provision of laboratory facilities. Gift of phytoalexin samples by Dr S. Pueppke and Dr N.T. Keen is gratefully acknowledged. East-West Center, Honolulu, Hawaii, USA, is thanked for the financial assistance.     

Oxydation der Zucker durch Süssmandelemulsin (Rohferment nachHelferich)

Summary Emulsin (Rohferment ofHelferich) and similar enzyme preparations ofRosaceae-Amygdaloideae seeds have been found to exhibit a low but definite oxidizing activity towards aldohexoses in concentrated sugar solutions used for transglycosylation experiments.     

Occurrence of sepiapterin deaminase in the normal type silkworm,Bombyx mori

Summary Sepiapterin deaminase was prepared from the normal strain of the silkworm, Bombyx mori. After inhibition experiments, this enzyme was found to have the same properties as that isolated from the lemon mutant strain. Several new inhibitors and their K₁ values are described for the deaminase.The authors wish to thank Dr Wm. Gyure, Cape Cod Hospital, Hyannis, Massachusetts, USA, for his help in preparing this report.     

Study of the metabolites ofPhyllosticta maydis. I. Isolation and partial identification

Summary Various metabolites of the fungusPhyllosticta maydis have been isolated, particularly mevalonolactone. The most interesting of these compounds, which is highly toxic to corn seeds (Zea mays), and which is probably a complex polyol, is the subject of the present report.Acknowledgment. The authors are indebted to Professor T. Gäumann for his cooperation and Dr J.C. Tabet who performed the measurements of mass-spectrometry.