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1.
Deficient fumarase activity in an infant with fumaricacidemia and its distribution between the different forms of the enzyme seen on isoelectric focusing. 总被引:1,自引:0,他引:1
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R Petrova-Benedict B H Robinson T E Stacey J Mistry R A Chalmers 《American journal of human genetics》1987,40(3):257-266
A male infant, whose parents were first cousins, presented at 6 mo of age with hypotonia, microcephaly, and delayed development. He was found to have large amounts of fumaric and succinic acids present in the urine. In lysed cultured skin-fibroblast preparations, the activity of fumarase was found to be 22.7% of that in controls. Cell fractionation by homogenization and by digitonin treatment indicated that the residual activity in the cells of the patient was primarily located in the mitochondrial fraction rather than in the cytosolic fraction. Isoelectric focusing of fibroblast extracts showed that six bands of fumarase activity were discernible in control cell lines, two of them cytosolic with pI's of 5.53 and 5.60 and four of them mitochondrial with a pI of 5.65-6.8. In contrast, isoelectric focusing of fibroblast extracts from the fumarase-deficient patient showed only a single band of activity with a pI corresponding to the mitochondrial type seen in the controls. Immunoprecipitation of proteins with rabbit antifumarase antibody in (35S)-methionine-labeled fibroblasts indicated that a protein of correct size (Mr = 44,000 daltons) corresponding to fumarase was synthesized in similar amounts in both the patients and controls. It is proposed that in the patient's cells a single active species of fumarase that is mitochondrial in location is synthesized. Since it is known that mitochondrial and cytosolic fumarases are encoded by the same gene but differ slightly in amino acid sequence, it is possible that a point mutation might explain these findings. 相似文献
2.
The viability ofMycobacterium leprae, maintained within 33B Schwannoma cells, was estimated in terms of incorporation of [14C] acetate into its specific phenolic glycolipid-1. This measure of viability was correlated with two other assays,viz., fluorescein diacetate/ethidium bromide staining and mouse footpad growth. Observation of a 2-fold increase in the number
of intracellularMycobacterium leprae over an experimental period of 12 days also corroborated this contention. Furthermore, on addition of anti-leprosy drugs
to these intracellularMycobacterium leprae there was significant decrease in phenolic glycolipid-1 synthesis indicative of loss of viability of the organisms. This
study also established the importance of the host cell for active bacillary metabolism, asMycobacterium leprae maintained in cell-free conditions showed no incorporation into phenolic glycolipid-1. Moreover, compromising the host’s
protein synthesis capacity with cycloheximide, also led to reduction in bacillary metabolism. As this system measures the
metabolic synthesis of a uniqueMycobacterium leprae component, it would be useful for development and screening of compounds acting against specific bacillary targets. 相似文献
3.
The direct microbial conversion (DMC) process for the production of ethanol from lignocellulosic biomass is limited by low volumetric ethanol production rates due to the low cell densities of Clostridium thermosaccharolyticum which is a key organism for ethanol production in this process. Hence, this study focuses on the use of a continuous- culture cell recycle system to improve the volumetric ethanol productivity and yield of the fermentation of xylose by C. thermosaccharolyticum. Early experiments with the continuous-culture cell recycle system showed a two-fold improvement in volumetric ethanol productivity. However, the ethanol yield at the higher dilution rates suffered because of the large amount of lactate produced. The manipulation of two environmental parameters-iron concentration in the nutrient medium and the N(2) purge rate of the fermentor headspace-allowed a dramatic reduction in the lactate production and a simultaneous improvement in the ethanol titer and yield. Under the improved conditions of increased iron concentration (12.5 mg/L FeSO(4) . 7H(2)O) and decreased N(2) purge rate (0.1 L/min), a continuous culture of C. thermosaccharolyticum operating at a dilution rate of 0.24 h(-1) and 50% cell recycle produced 8.6 g/L ethanol and less than 1 g/L each of acetate and lactate. The volumetric ethanol productivity was 2.2 g/L/h, which is 8 times larger than obtained for a continuous culture operated with no cell recycle and the same specific growth rate. 相似文献
4.
Systemic administration of Neurotensin, a tridecapeptide, in immature rats treated with estradiol benzoate significantly enhances uterine DNA synthesis as reflected by the incorporation of 3H-thymidine. The peptide may have a direct action on the uterus. Substance P, a related peptide, had no effect on uterine DNA synthesis. 相似文献
5.
It is now well established that the mycotoxin zearalenone and some of its derivatives possess oestrogenic activity. In the present study, the binding characteristics of [3H]zearalanol (P-1496) to different classes of sites including [1] the oestrogen receptor, [2] the higher capacity lower affinity (HCLA) sites, [3] the antioestrogen sites and [4] a new class of binding sites apparently specific for P-1496 were examined in rat liver. Analysis of the binding by sucrose density gradient centrifugation confirmed that P-1496 binds to the oestrogen receptor but not to the higher capacity lower affinity sites for oestradiol-17 beta. Furthermore, saturation experiments using partially-purified fractions showed that P-1496 binds to the oestrogen receptor with an affinity very similar to that of oestradiol-17 beta (apparent dissociation constants ranged from 0.1-0.3 nM). Competition studies using partially purified cytosolic oestrogen receptor suggested that P-1496 binds to a second high affinity site distinct from the oestrogen receptor. This binding site was further characterized as selective for P-1496 by saturation analysis following the complete occupancy of oestrogen receptor by oestradiol-17 beta. The in vitro binding characteristics of P-1496 were then compared with in vivo effects on concentrations of serum triglycerides. Treatment of ovariectomized female rats daily with 1.5 or 2 mg P-1496/kg body weight resulted in marked increases in the concentrations of serum triglycerides associated with the very low density lipoprotein (VLDL) fraction. Dose-response studies indicated that there was no sex difference with respect to the dose necessary to produce significant increases in serum triglycerides. The present study shows striking similarities between the binding of P-1496 and oestradiol-17 beta to liver oestrogen receptor in vitro. However, differences are observed with respect to their binding to other cytoplasmic components of liver. In addition, although P-1496 is capable of eliciting in vivo oestrogenic effects in liver, it is much less potent than oestradiol-17 beta. 相似文献
6.
Abnormal high density lipoproteins from patients with liver disease regulate cholesterol metabolism in cultured human skin fibroblasts 总被引:2,自引:0,他引:2
J S Owen H Goodall P Mistry D S Harry R C Day N McIntyre 《Journal of lipid research》1984,25(9):919-931
Apolipoprotein B (apoB) of plasma low density lipoproteins (LDL) binds to high affinity receptors on many cell types. A minor subclass of high density lipoproteins (HDL), termed HDL1, which contains apoE but lacks apoB, binds to the same receptor. Bound lipoproteins are engulfed, degraded, and regulate intracellular cholesterol metabolism and receptor activity. The HDL of many patients with liver disease is rich in apoE. We tested the hypothesis that such patient HDL would reduce LDL binding and would themselves regulate cellular cholesterol metabolism. Normal HDL had little effect on binding, uptake, and degradation of 125I-labeled LDL by cultured human skin fibroblasts. Patient HDL (d 1.063-1.21 g/ml) inhibited these processes, and in 15 of the 25 samples studied there was more than 50% inhibition at 125I-labeled LDL and HDL protein concentrations of 10 micrograms/ml and 25 micrograms/ml, respectively. There was a significant negative correlation between the percentage of 125I-labeled LDL bound and the apoE content of the competing HDL (r = -0.54, P less than 0.01). Patient 125I-labeled HDL was also taken up and degraded by the fibroblasts, apparently through the LDL-receptor pathway, stimulated cellular cholesterol esterification, increased cell cholesteryl ester content, and suppressed cholesterol synthesis and receptor activity. We conclude that LDL catabolism by the receptor-mediated pathway may be impaired in liver disease and that patient HDL may deliver cholesterol to cells. 相似文献
7.
S Onesti L F Lloyd D Maeder A Mistry P Brick D Blow D M Blow 《Journal of molecular biology》1989,210(1):241-242
Crystals of an inhibitor of trypsin and tissue plasminogen activator from seeds of the legume Erythrina caffra have been obtained by vapour diffusion. The crystals belong to the hexagonal space group P6(1)22 (or its enantiomorph P6(5)22) with cell parameters 73.4 A and 143.0 A. There is one molecule in the asymmetric unit. The crystals diffract to beyond 2.5 A resolution. 相似文献
8.
Suresh Chand Purnima Basu Neeti Maheshwari 《Journal of plant biochemistry and biotechnology.》1994,3(1):53-54
Somatic embryogenesis and regeneration of plantlets was achieved In callus cultures derived from cotyledonary leaf pieces of Hyoscyamus muticus L on MS medium enriched with 2 mg/l 2,4–0 and 0.5 mg/l BAP. For embryogenesis and organogenesis varying concentrations of NAA with or without BAP were added In the medium. Organogenesis was also achieved when callus was transferred to the hormone free medium. 相似文献
9.
Ambikesh Soni Manohar Prasad Bhandari Gagan Kant Tripathi Priyavand Bundela Pradeep Kumar Khiriya Purnima Swarup Khare Manoj Kumar Kashyap Abhijit Dey Balachandar Vellingiri Suresh Sundaramurthy Arisutha Suresh José M. Pérez de la Lastra 《Journal of cellular and molecular medicine》2023,27(6):737-762
In recent years, drug manufacturers and researchers have begun to consider the nanobiotechnology approach to improve the drug delivery system for tumour and cancer diseases. In this article, we review current strategies to improve tumour and cancer drug delivery, which mainly focuses on sustaining biocompatibility, biodistribution, and active targeting. The conventional therapy using cornerstone drugs such as fludarabine, cisplatin etoposide, and paclitaxel has its own challenges especially not being able to discriminate between tumour versus normal cells which eventually led to toxicity and side effects in the patients. In contrast to the conventional approach, nanoparticle-based drug delivery provides target-specific delivery and controlled release of the drug, which provides a better therapeutic window for treatment options by focusing on the eradication of diseased cells via active targeting and sparing normal cells via passive targeting. Additionally, treatment of tumours associated with the brain is hampered by the impermeability of the blood–brain barriers to the drugs, which eventually led to poor survival in the patients. Nanoparticle-based therapy offers superior delivery of drugs to the target by breaching the blood–brain barriers. Herein, we provide an overview of the properties of nanoparticles that are crucial for nanotechnology applications. We address the potential future applications of nanobiotechnology targeting specific or desired areas. In particular, the use of nanomaterials, biostructures, and drug delivery methods for the targeted treatment of tumours and cancer are explored. 相似文献
10.
In vitro clonal propagation of Capparis decidua was achieved using nodal explants from mature trees, and cotyledonary node, cotyledon and hypocotyl explants taken from the seedlings. Explants cultured on MS medium supplemented with BAP showed differentiation of multiple shoots and shoot buds in 4–5 weeks in the primary cultures. The medium with BAP (5 mg/l) was the best for shoot bud proliferation from the nodal as well as seedling explant. Shoot multiplication was best on cotyledonary node. In the nodal explants shoot multiplication was best on medium supplemented with 5 mg/l BAP and after second subculturing further multiplication of shoot buds was highest on the medium containing 3 mg/l BAP. Shoots were separated from mother cultures in each subculturing for rooting. Rooting was best achieved using 1 mg/l IBA in the medium. Rooted plantlets were transferred td earthen pots with garden soil and peat moss mixture. 相似文献