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51.
Gliocladium sp. TUB F-498, a wild strain of a lignocellulolytic fungus with a fast growth rate and enzyme production rate was selected as a potential in situ enzyme source for the bioprocessing of pretreated poplar wood (PPW) to ethanol in a simultaneous saccharification and fermentation process. TUB F-498 produced 77 filter paper units of cellulase activity and 246 IU of -glucosidase activity per g dry weight of substrate utilized, as compared with the highly successful mutant reference strain Trichoderma reesei Rut-C30, which produced 100 filter paper units and 92 IU per g dry weight substrate in a stirred-tank fermentation. TUB F-498 also produced more xylanase and endoglucanase activity than Rut-C30 on PPW in shake-flask fermentations. 相似文献
52.
The division Haptophyta is represented only by about 300 extant species showing wide diversity in morphology, biochemistry and ecology. They have a world-wide distribution and are numerically important in phytoplankton populations in nearly all marine environments. Evidence from the geological record shows that they have been the major constituent of calcareous deposits since the Late Triassic and, as they have evolved quickly through time, their coccoliths have always shown wide morphological diversity. In today's oceans they occasionally produce extensive blooms, visible by satellite imagery, which have ecological impact. As a consequence of these blooms the haptophyte algae are now receiving greater attention, as their role in the global sulphur and carbon cycles may influence the world's climate, and their potential as nuisance bloom algae have implications for commercial fishing and the marine ecosystem. As it is likely that these organisms have always produced such blooms, these effects may have been in operation for the last 200 million years. 相似文献
53.
This paper describes six species of permineralized pinoid woods with resin canals from the Upper Cretaceous of Hokkaido, Japan
and Saghalien:Piceoxylon transiens Shimakura,P. scleromedullosum Shimakura,P. macroporosum sp. nov.,P. takahashii sp. nov.,Pinuxylon microporosum Ogura andPinoxylon dakotense (Knowlton) Read (new to Saghalien and the Cretaceous).Piceoxylon macroporosum is characterized by large resin canals and rays without ray tracheids and in lacking tylosoids in resin canals.Piceoxylon takahashii, which resemblesP. scleromedullosum, is distinguished from the latter in having ray tracheids and nests of sclereids in pith.
Structure and affinities of the petrified plants from the Cretaceous of Northern Japan and Saghalien XVI. (continued from
Ohsawaet al. 1995) 相似文献
54.
P. K. Lee J. A. Buswell K. Shinagawa 《World journal of microbiology & biotechnology》1995,11(6):696-698
Eleven of 16 samples of rice on sale in rice shops and supermarkets in Hong Kong contained Bacillus cereus. Although B. cereus counts did not exceed 100 bacteria/g in most of the positive samples, a sample of Thai red rice and a poor quality rice originating from China contained between 300 to 1000 cells/g and 104 to 2×105 cells/g, respectively. Nine strains produced an enterotoxin responsible for the diarrhoeal-type B. cereus food poisoning and seven of these strains also produced a haemolysin (haemolysin BL), a dermonecrotic vascular permeability factor which may be a virulence determinant in diarrhoeal illness caused by this bacterium.P.K. Lee and J.A. Buswell are with the Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; K. Shinagawa is with the Department of Veterinary Medicine, Iwate University, Iwate, Japan. 相似文献
55.
The properties of enzymes and microbial cells as biocatalysts useful in natural products chemistry are discussed from the perspective of the chemical transformations they catalyse. Attention is focused on numerous reactions of value to natural products chemists, including the acyloin condensation, Baeyer-Villiger oxidation, regio- and enantioselective ester hydrolyses, oxidations of aromatic and non-aromatic substrates, oxidoreduction and O- and N-dealkylations. Compounds considered in this review include amino acids, alkaloids, antibiotics, coumarins, naphthoquinones, quassinoids, rotenoids and mono-, sesqui-, di- and triterpenoid substrates. The value of biocatalysis compared with traditional chemical catalysis is considered within the broad framework of natural products chemistry, and the potential for using immobilized enzyme and cell technology is presented. 相似文献
56.
Opender Koul 《Entomologia Experimentalis et Applicata》1984,36(1):85-88
Azadirachtin, a material isolated from Azadirachta indica A. Juss, was applied to various stages of red cotton bugs (Dysdercus koenigii F.). The phytochemical evoked various specific and nonspecific effects during the course of development. Prolonged development, wing deformities unplasticisation of wing lobes, development of wingless adults and larval mortality were the characteristic features.
Azadirachtine d'Azadirachta indica I: Interaction avec de développement de Dysdercus koenigii
Résumé L'azadirachtine, isolat de Azadirachta indica A. Juss a été utilisée (par traitement du substrat ou par dépôt sur l'insecte) sur un hétérométabole, Dysdercus koenigii F. Cette substance phytochimique provoque divers effets, spécifiques ou non, pendant le développement.Les modifications caractéristiques sont: un développement prolongé, de déformations alaires, une absence de plastification des bourgeons alaires, une production d'adultes sans ailes et une mortalité nymphale.De tels résultats suggèrent des études complémentaires pour mettre en évidence une hormone d'éclosion chez D. koenigii avec laquelle interférerait l'azadirachtine.相似文献
57.
Taenia taeniaeformis: characterization of larval metabolic products and growth of host gastric cells in vitro 总被引:1,自引:0,他引:1
Development of larvae of the cestode parasite Taenia taeniaeformis in the liver of rats induces gross hyperplasia of the gastric mucosa and excessive mucus production in the stomach without any direct contact with the stomach. Because the taeniid larvae are known to elaborate excretory-secretory (E-S) product in vivo and in vitro, the product was analyzed further, and its effects on cultured rat and dog stomach cells were investigated. In vitro E-S product contained less negatively charged glycosaminoglycan than either heparin or chondroitin sulfate, and proteins of various molecular weights. It stimulated the growth of both rat and dog stomach cells at concentrations of 3-9 micrograms protein/ml culture medium. At a concentration of 30 micrograms protein/ml culture medium, it stimulated hexosamine production in the cells up to 20 times, and multiple intracytoplasmic granules were found in both rat and dog cultured cells by light and electron microscopy. These results suggest that larval E-S product may be involved in the induction of gastric hyperplasia and hypermucus secretion. 相似文献
58.
Summary Wahsed thylakoid membranes from pea chloroplasts incorporate label from (35S)-methionine into protein when supplemented with S-30 soluble factors from E. coli. One of the products associated with the thylakoids is soluble in butanol, precipitated by ether and has an apparent molecular mss of 8200D on urea-lithium dodecyl sulphate (LDS) polyacrylamide gels. In addition, the protein covalently binds dicyclohexylcarbo-diimide (DCCD) which causes it to migrate as two slower forms on gels. Based on these criteria we establish that the proteolipid or subunit III of CF0 (the intrinsic sector of the ATPase complex) is synthesized by the thylakoid bound polysomes. 相似文献
59.
Summary In the corpora cardiaca of the insect Leucophaea the administration of serotonin elicits ultrastructural features indicative of the extrusion of neurosecretory material by exocytosis. The response to the stimulus and the process of extrusion seem to occur at considerable speed. Nearly all of the 30 test animals, fixed at various intervals starting as early as 3 min after the injection of the drug, show granules captured at the moment of leaving the axon as well as fully exteriorized secretory material. The fact that many of these granules are much smaller than the typical neurosecretory type speaks for intracellular fragmentation of the latter prior to the discharge of this cellular product. After 25 min or more the extruded electron dense structures show signs of breakdown. The apparent speed of these phenomena accounts for the dearth of omega-type configurations observed in unstimulated specimens of this species. The possible relationship between the membrane phenomena involved in exocytosis and the transient protrusions of bounding membranes of neurosecretory granules described in earlier papers remains to be clarified.Supported by N.S.F. research grant BMS 74-12456 相似文献
60.
Hilary Glover 《Journal of phycology》1977,13(3):208-212
Cultures of Isochrysis galbana Parks and Phaeodactylum tricornutum Bohlin were grown in iron-limited chemostats. With increasing iron deficiency, photosynthetic rate per cell and assimilation number decreased. The pattern of photosynthesis was also altered; in Fe deficient cells the proportion of 14C fixed in glycine and serine decreased with an accompanying increase into alanine after 3 min assimilation. Although there was no significant effect of Fe deficiency on the proportion of 14C incorporated into total amino acids and amides, the percentage of total 14C fixed in protein increased with increasing Fe deficiency. Cellular levels of chlorophyll a, carotenoids, cytochromes and protein also decreased with increasing Fe deficiency. However, the reduction in chlorophyll a/cell was not as great as that of cytochrorne f1 and Fe deficient cells therefore showed a marked increase in chlorophyll a:cytochrorne f1 ratio. 相似文献