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41.
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A test of root growth inhibition of spruce and beech roots, according to Lynch's procedure (1977), shows the inhibitory effects of soil solution extracted from the holorganic layers (Of2-Oh) under beech and spruce. Molecular gel filtration of soil solutions shows that the molecular weights vary over a wide range, from less than 100 to over 40,000 daltons. Chemical analysis, using CGC, HPLC and sometimes MS shows only negligible concentrations of simple aliphatic (C1-C5) and aromatic acids in the free state. Using the fraction scheme of Forsyth (1977) and the carbazole procedure, it is shown that uronic acids represent only a small percentage of the carboxylic acids, and have no inhibitory effects on root growth. By analogy with results of other authors, the presence of polycarboxylic acids in the soil solution are considered to be the main cause of root growth inhibition. 相似文献
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Solid-phase synthesis of the nucleopeptide fragment H-Asp-Ser[pAAAGTAAGCC]-Glu-OH from the nucleoprotein of Bacillus subtilis phage phi 29. 下载免费PDF全文
C M Dreef-Tromp J C van der Maarel H van den Elst G A van der Marel J H van Boom 《Nucleic acids research》1992,20(15):4015-4020
The naturally occurring DNA-nucleopeptide H-Asp-Ser[5'-pAAAGTAAGCC-3']-Glu-OH was prepared via a solid-phase phosphite triester approach using N-2-(tert-butyldiphenylsilyloxymethyl)benzoyl protected nucleosides. The oligonucleotide was linked via the extremely base-labile oxalyl ester anchor to the solid support. 相似文献
45.
Heterologous gene expression in Lactococcus lactis subsp. lactis: synthesis, secretion, and processing of the Bacillus subtilis neutral protease 总被引:1,自引:0,他引:1
M van de Guchte J Kodde J M van der Vossen J Kok G Venema 《Applied and environmental microbiology》1990,56(9):2606-2611
The Bacillus subtilis nprE gene lacking its own promoter sequence was inserted in the lactococcal expression vector pMG36e. Upon introduction of the recombinant plasmid into Lactococcus lactis subsp. lactis strain MG1363, neutral protease activity could be visualized by the appearance of large clearing zones around colonies grown on milk agar plates. By measuring the activities of the neutral protease and the intracellular enzyme lactate dehydrogenase in culture supernatants and cell fractions, it was demonstrated that the neutral protease was actively secreted into the growth medium. This was corroborated by using the Western blot (immunoblot) technique, which showed the presence of the mature form of the neutral protease in the culture supernatant. On the basis of these results, it is concluded that the B. subtilis neutral protease gene was expressed in L. lactis and that the gene product was secreted into the growth medium and was apparently correctly processed to produced a biologically active protein. The secretion of this particular enzyme may be helpful in achieving accelerated cheese ripening. 相似文献
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Steven D. Johnson Marco G. Balducci Alison Bijl Miguel Castañeda-Zárate Ruth J. Cozien Carmen R. Ortmann Timotheüs van der Niet 《Ecological Entomology》2020,45(3):751-755
1. Diel rhythms of foraging activity by animal flower visitors can reflect niche partitioning and are considered an important component of selection on floral traits. However, it has been notoriously difficult to obtain objective information on the patterns of flower visitation by crepuscular and nocturnal insects. 2. Motion-activated cameras were used for field-based studies of hawkmoth foraging behaviour on six African plant species. 3. The results showed that short-tongued hawkmoth species forage mainly around dusk and then sporadically throughout the night, whereas long-tongued hawkmoth species feed consistently throughout the night, with a peak shortly before midnight. 4. These results provide the first quantitative estimates of diel patterns of interactions between multiple hawkmoth and plant species and, when combined with qualitative reports from other studies, suggest that differences in diel activity between the two main hawkmoth functional groups (short- and long-tongued) are consistent across the Old and New Worlds. 相似文献
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New lessons in the regulation of glucose metabolism taught by the glucose 6-phosphatase system. 总被引:6,自引:0,他引:6
G van de Werve A Lange C Newgard M C Méchin Y Li A Berteloot 《European journal of biochemistry》2000,267(6):1533-1549
The operation of glucose 6-phosphatase (EC 3.1.3.9) (Glc6Pase) stems from the interaction of at least two highly hydrophobic proteins embedded in the ER membrane, a heavily glycosylated catalytic subunit of m 36 kDa (P36) and a 46-kDa putative glucose 6-phosphate (Glc6P) translocase (P46). Topology studies of P36 and P46 predict, respectively, nine and ten transmembrane domains with the N-terminal end of P36 oriented towards the lumen of the ER and both termini of P46 oriented towards the cytoplasm. P36 gene expression is increased by glucose, fructose 2,6-bisphosphate (Fru-2,6-P2) and free fatty acids, as well as by glucocorticoids and cyclic AMP; the latter are counteracted by insulin. P46 gene expression is affected by glucose, insulin and cyclic AMP in a manner similar to P36. Accordingly, several response elements for glucocorticoids, cyclic AMP and insulin regulated by hepatocyte nuclear factors were found in the Glc6Pase promoter. Mutations in P36 and P46 lead to glycogen storage disease (GSD) type-1a and type-1 non a (formerly 1b and 1c), respectively. Adenovirus-mediated overexpression of P36 in hepatocytes and in vivo impairs glycogen metabolism and glycolysis and increases glucose production; P36 overexpression in INS-1 cells results in decreased glycolysis and glucose-induced insulin secretion. The nature of the interaction between P36 and P46 in controling Glc6Pase activity remains to be defined. The latter might also have functions other than Glc6P transport that are related to Glc6P metabolism. 相似文献