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1.
Pratima Bajpai Anshula Sharma N. Raghuram Pramod K. Bajpai 《Biotechnology letters》1988,10(3):217-220
Summary Ethanol concentration and fermentation productivities were substantially increased when soya extract was added to the fermentation medium using immobilized cells of a locally isolated strain of S. cerevisiae. Very high concentrations, 152 and 162 g/l of ethanol, were obtained from a medium containing 300 and 350 g/l sugars respectively by supplementing the medium with soya extract. The fermentation time was also reduced by more than 50%. 相似文献
2.
The regulation of''early'' enzymes during the development and dedifferentiation of Dictyostelium discoideum 总被引:2,自引:0,他引:2
Stephen Alexander Ann Mane Cibulsky Lee Mitchell David R. Soll 《Differentiation; research in biological diversity》1985,30(1):1-6
The specific activities of the enzymes alpha-mannosidase and N-acetylglucosaminidase increase immediately after the initiation of the development of bacterially grown cell cultures of Dictyostelium discoideum. The regulation of these two enzymes was found to be dissociable in the developmental timer mutant, FM-1, which aggregates 4.5 h earlier than wild-type cells due to the absence of the first rate-limiting component of the preaggregative period. The increase in alpha-mannosidase activity occurs in the absence of the first rate-limiting component, but the increase in N-acetylglucosaminidase activity does not. These results indicate the following: (1) the increase in the specific activity of alpha-mannosidase is not related to the timing of subsequent developmental stages; (2) the increase in the specific activity of N-acetylglucosaminidase is not necessary for the subsequent developmental program; and (3) either the increase in the specific activity of N-acetylglucosaminidase is dependent upon progress through the first rate-limiting component, or the increase in this enzyme activity and the first rate-limiting component are both dependent upon an early event for which FM-1 is defective. In addition to early development, we monitored the two enzyme activities during dedifferentiation. The results demonstrate that there is no difference between dedifferentiating wild-type cells and dedifferentiation-defective mutant HI-4 cells. Changes in enzyme specific activity accompanying dedifferentiation are dependent upon the composition of the dedifferentiation-inducing media and are consistent with the levels of these enzymes observed in cells growing in the different nutrient media. 相似文献
3.
Shyamali Mukherjee Mihir Nag Tultul Nayyar Indrani Maitra Parul Chakrabarti Pramod R. Dasgupta 《Journal of biosciences》1986,10(3):311-317
The effect of estradiol-17β and progesterone given separately as well as in combination on the rate of hydrogen peroxide formation
and lipid peroxidation in the uteri of ovariectomized rats was studied. Estradiol in 3μg dose per day per animal elicited maximum stimulatory response and progesterone (100μg), on the other hand, was without any such effect. However, progesterone given along with estradiol completely prevented the
effect due to the latter. In the same way, vitamin E, a well known antioxidant was found to be extremelv effective in protecting
the uterus from the highly peroxidative action of estradiol-17β. 相似文献
4.
5.
Prem Pritam Aditya P. Sarnaik Pramod P. Wangikar 《Biotechnology and bioengineering》2023,120(8):2363-2370
With multiple applications in food, pharmaceutical, and chemical industries as antioxidant or nonmetabolizable sweetener; the bioproduction of d -mannitol is gaining global attention, especially with photosynthetic organisms as hosts. Considering the sustainability prospects, the current work encompasses metabolic engineering of a widely used cyanobacterial strain, Synechococcus elongatus PCC 7942, and two newly isolated fast-growing cyanobacterial strains; S. elongatus PCC 11801 and S. elongatus PCC 11802, for mannitol production. We engineered these strains with a two-step pathway by cloning genes for mannitol-1-phosphate dehydrogenase (mtlD) and mannitol-1-phosphatase (mlp), where the mtlD expression was under the control of different promoters from PCC 7942, namely, Prbc225, PcpcB300, PcpcBm1, PrbcLm17, and PrbcLm15. The strains were tested under the “switch conditions,” where the growth conditions were switched after the first 3 days, thereby resulting in differential promoter activity. Among the engineered strains of PCC 11801 and PCC 11802, the strains possessing Prbc225-mtlD module produced relatively high mannitol titers of 401 ± 18 mg/L and 537 ± 18 mg/L, respectively. The highest mannitol titer of 701 ± 15 mg/L (productivity 60 mg/L.d, yield 895 µM/OD730) was exhibited by the engineered strain of PCC 7942 expressing PcpcB300-mtlD module. It is by far the highest obtained mannitol yield from the engineered cyanobacteria. 相似文献
6.
Summary
Zymomonas mobilis cells were immobilized into small 1 mm diameter beads of Ca-alginate in order to minimize mass transfer limitations and maximize immobilized cell activity. A combination of small bead size with a high cell concentration of 58 g dry wt. cell per lit. bead volume resulted in high ethanol productivities using a newly designed packed bed bioreactor system. Steady-state dilution rates ranging from 0.4 h-1 to 3.9 h-1 were run resulting in a maximum productivity of 102 g ethanol/l/h for an inlet substrate concentration of 100 g glu/l and 87% conversion. The bioreactor was run continuously at a fixed dilution rate for 384 h and short intermittent treatment of the beads with CaCl2 temporarily increased ethanol productivity to a maximum of 116 g ethanol/l/h. 相似文献
7.
Effect of sodium butyrate on mammalian cells in culture: A review 总被引:10,自引:0,他引:10
Kedar N. Prasad Pramod K. Sinha 《In vitro cellular & developmental biology. Plant》1976,12(2):125-132
Summary Sodium butyrate produces reversible changes in morphology, growth rate, and enzyme activities of several mammalian cell types
in culture. Some of these changes are similar to those produced by agents which increase the intracellular level of adenosine
3′,5′-cyclic monophosphate (cAMP) or by analogs of cAMP. Sodium butyrate increases the intracellular level of cAMP by about
two fold in neuroblastoma cells; therefore, some of the effects of sodium butyrate on these cells may in part be mediated
by cAMP. Sodium butyrate appears to have properties of a good chemotherapeutic agent for neuroblastoma tumors because the
treatment of neuroblastoma cells in culture causes cell death and “differentiation”; however, it is either innocuous or produces
reversible morphological and biochemical alterations in other cell types. 相似文献
8.
U. H. Mane 《Hydrobiologia》1975,47(3-4):439-451
- The neutral red technique was employed to study the rate of filtration in Katelysia opima.
- The weight specific water filtration was found to be greater for younger clams compared to the older ones.
- The rate of water filtration increased with decreasing salinity.
- Water filtration was found to increase as temperature increased, reaching a maximum at 35°C. but then sharply decreasing at 39°C.
- Light had no significant effect on the rate of filtration.
- Suspended matter was found to affect the rate of water filtration.
- The rate of filtration was low at high pH and high in low pH.
- The rate of water filtration was found to be faster during high tide than during low tide.
- The presence of the parasitic crab, Pennotheris sp., in the mantle cavity of clams had a marked effect on the particle filtration.
- Accidental cut of the siphon tips had no effect on the rate of filtration.
9.
Pramod B. Pansuriya Mohan N. Patel 《Journal of enzyme inhibition and medicinal chemistry》2013,28(1):108-119
The structural and spectroscopic properties of novel five-coordinated dimeric-Cu(II) system have been investigated. The biocidal activities of all eight compounds, ligands, cupric nitrate and standard drugs against six bacteria and three fungi were determined. The DNA interaction activity of complexes was studied using spectrophotometry and electrophoresis. The superoxide dismutase (SOD)-like activity of the complexes was compared with previously reported monomeric- and dimeric copper complexes. The results support the five-coordinated dimeric square pyramidal geometry for the quinolone-Cu(II) system. 相似文献
10.
Hyoscyamine 6β-hydroxylase (H6H; EC 1.14.11.11), an important enzyme in the biosynthesis of tropane alkaloids, catalyzes the hydroxylation of hyoscyamine to give 6β-hydroxyhyoscyamine and its epoxidation in the biosynthetic pathway leading to scopolamine. Datura metel produces scopolamine as the predominant tropane alkaloid. The cDNA encoding H6H from D. metel (DmH6H) was cloned, heterologously expressed and biochemically characterized. The purified recombinant His-tagged H6H from D. metel (DmrH6H) was capable of converting hyoscyamine to scopolamine. The functionally expressed DmrH6H was confirmed by HPLC and ESI-MS verification of the products, 6β-hydroxyhyoscyamine and its derivative, scopolamine; the DmrH6H epoxidase activity was low compared to the hydroxylase activity. The Km values for both the substrates, hyoscyamine and 2-oxoglutarate, were 50 μM each. The CD (circular dichroism) spectrum of the DmrH6H indicated a preponderance of α-helicity in the secondary structure. From the fluorescence studies, Stern–Volmer constants for hyoscyamine and 2-oxoglutarate were found to be 0.14 M?1 and 0.56 M?1, respectively. These data suggested that the binding of the substrates, hyoscyamine and 2-oxoglutarate, to the enzyme induced significant conformational changes. 相似文献