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51.
Summary
Fusarium oxysporum 841 produces a mixture of ethanol and acetic acid from glucose, xylose or Avicel (microcrystalline cellulose) substrates. Some metabolic inhibitors viz. sodium azide, dinitrophenol and polyethylene glycol were used for shifting product formation from acetic acid to ethanol. Using these inhibitors 1.5- to 2- fold increase in ethanol production was achieved with significant repression (by 80 to 90%) of acetic acid. Almost theoretical yields of ethanol were obtained. 相似文献
52.
53.
Prem Kumar Dantu Sant S. Bhojwan 《Journal of plant biochemistry and biotechnology.》1992,1(2):115-118
Effect of some physical and chemical factors on in vitro shoot multiplication in Gladioius was investigated. A modified MS medium with NH4NO3 reduced to half strength, KH2PO4 replaced with 300 mg/l of NaH2PO4 2 H2O and Kl omitted completely, was found to be better than the original MS. BAP was better than either kinetin or 2iP. Of the various physical factors studied, the propagule size, light and container volume influenced the rate of shoot multiplication. On the modified medium containing 0.5 mg/l BAP in dark, the propagules bearing 20 buds showed 8-fold multiplication. 相似文献
54.
Summary Four strains of Fusarium oxysporum and a strain of Monilia brunnae were screened for their ability to convert cellulosic substrates into ethanol/acetic acid. These strains were found to utilize cellulose and produce extracellular cellulases. However, only F. oxysporum 841 was found to convert glucose, xylose, and cellulose into ethanol and acetic acid as major end-products under microaerobic conditions. Acetic acid at a level of 4.7 g/l resulted in a single-step process on potato pulp medium, indicating the potential of the strain for converting cellulosic substrates into acetic acid.
Offprint requests to: K. Schügerl 相似文献
55.
Mini-mu derivatives carrying plasmid replicons can be used to clone genesin vivo. This method was adopted to generate phasmid clones which were later screened for their ability of restore nitrofurantoin
sensitivity of a nitrofuran-resistant host by eliciting nitroreductase activity. One phasmid-derived clone (pAJ101) resulted
in considerable increase in nitroreductase activity when introduced into a nitrofurantoin-resistant mutant ofEscherichia coli with reduced nitroreductase activity. Subsequently, a 1.8 kb fragment obtained from pAJ101 by partial digestion with 5au3A,
was subcloned into pUC18 to yield pAJ102. The nitroreductase activity attributable to pAJ102 was capable of reducing both
nitrofurantoin and nitrofurazone. The polypeptides encoded by pAJ102 were identified by the minicell method. A large, well-defined
band corresponding to 37 kDa and a smaller, less-defined band corresponding to 35 kDa were detected. Tnl000 mutagenesis was
used to delineate the coding segment of the 1.8 kb insert of pAJ102. A 0.8 kb stretch of DNA was shown to be part of the nitroreductase
gene. The gene was mapped at 19 min on theEscherichia coli linkage map. 相似文献
56.
Sujata Misra Kshudiram Naskar Dwijen Sarkar Dilip Kumar Ghosh 《Molecular and cellular biochemistry》1991,102(1):13-18
Summary
Leishmania donovani, the etiological agent for the disease visceral leishmaniasis, attach themselves to the macrophages for initiation of the disease. The attachment process has been found to be regulated by Ca2+ ions. Verapamil, a Ca2+-channel blocker inhibits Leishmania-macrophage attachment. The inhibitory effect is increased with time. Nifedipine, another Ca2+-channel blocker exhibits the same effect. The attachment process is stimulated by Ca2+-ionophore alone. The inhibitory effects of the calcium channel blockers are reversed by the ionophore. 相似文献
57.
The regulatory mechanism for the hormonal control of prolactin (PRL) and growth hormone (GH) gene expression in rat pituitary gland during gestation and lactation is verified in this study. The level of PRL-specific mRNA (mRNAPRL) sequences in the pituitary gland is elevated in the later part of gestation and more prominently so in lactation. In contrast the expression of GH gene is inhibited in the same tissue during gestation and lactation resulting in the dramatic decrease in the level of GH-specific mRNA (mRNAGH) sequences. We now demonstrate the influence of a tissue-specific altered DNA methylation pattern on the temporal modulation of expression of PRL and GH genes in the pituitary gland during alternate physiological states. An altered methylation pattern of specific "-C-" residues only in the coding region of PRL and GH gene can be detected concurrently with the altered level of expression of these genes in the pituitary gland during gestation and lactation. These results also demonstrate the dynamic state of methylation of specific -C- residues during the transition of these two genes from one state of expression to another in the same tissue. A correlation between site-specific DNA methylation and tissue-specific expression of PRL and GH gene in pituitary gland is reported. Thus a role of DNA methylation in the hormonal control of PRL and GH gene expression in physiological states such as pregnancy and lactation is proposed. 相似文献
58.
C B Siegall T T Hla A Kumar 《Biochemical and biophysical research communications》1988,154(3):1010-1017
Functional reconstitution of U1 small nuclear ribonucleoprotein particle (U1 snRNP) was performed using in vitro transcribed U1 snRNA. Hela cell nuclear extract was depleted of its constituent snRNPs by centrifugation at 100,000 X g. The supernatant was devoid of snRNAs and lacked cleavage activity in splicing reactions using in vitro transcribed beta-globin pre-mRNA as substrate. The resulting pellet which contained the snRNAs, retained 5' splice site cleavage activity in a similar splicing reaction. Supplementation of the inactive supernatant fraction with in vitro transcribed U1 snRNA, partially restored 5' splice site cleavage activity thereby demonstrating the specific requirement of U1 snRNP in the initial stage of pre-mRNA splicing. 相似文献
59.
The high molecular weight aminoacyl-tRNA synthetase complex (the 24S complex) was isolated from rat liver by ultracentrifugation. The lysyl-tRNA synthetase (E.C. 6.1.1.6) was selectively dissociated by hydrophobic interaction chromatography on 1,6 diaminohexyl agarose followed by hydroxylapatite chromatography and DEAE chromatography. The lysyl-tRNA synthetase dissociated from the 24S synthetase complex was purified approximately to 2700 fold with 14% yield. 相似文献
60.
The most abundant anhydrase isoenzyme from the erythrocyte of Indian buffalo has been purified using affinity gel and DEAE-cellulose ion-exchange columns and single crystals suitable for X-ray diffraction studies have been obtained. The unit cell dimensions are a = 46.8 A, b = 104.5 A, c = 60.4 A, beta = 91.2 degrees and the space group is P2(1), with two molecules per asymmetric unit. 相似文献