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1.
Stephen P. Schiffer Michal Prochazka Peter F. Jezyk Thomas H. Roderick Marc Yudkoff Donald F. Patterson 《Biochemical genetics》1989,27(1-2):47-58
A metabolic screening program of inbred strains of mice has detected a marked organic aciduria in the BALB/cByJ strain. Gas chromatographic and mass spectrometric analysis identified large quantities ofn-butyrylglycine plus lesser quantities of ethylmalonic acid. Crosses with the nonexcreting C57BL/6J strain indicate that this condition is inherited as an autosomal recessive trait. Independently from this screening a variant with no detectable enzyme activity of butyryl CoA dehydrogenase (BCD) in liver and kidney of the BALB/cByJ strain but not other BALB/c sublines was discovered. Data from a three-point cross indicated that the null variant maps to the structural locus for the enzyme,Bcd-1, on chromosome 5. The findings indicate that a mutation at or nearBcd-1 in the BALB/cByJ strain resulted in a biochemical abnormality manifest as the BCD deficiency. It is concluded that accumulation of butyryl CoA due to a block in the oxidation of short-chain fatty acids results in an overproduction of organic metabolites leading to the observed organic aciduria. The fact that other BALB/c substrains do not exhibit this abnormality further suggests that this disorder reflects subline divergence within the BALB/c family.This work was supported by NIH Grants RR02512 and GM32592 to the University of Pennsylvania and HD23168, NS17752, and HD08536 to the Children's Hospital of Philadelphia, National Science Foundation Grant BSR 84-18828 to The Jackson Laboratory, and a Postdoctoral Fellowship from the Juvenile Diabetes Foundation International to Dr. Prochazka. 相似文献
2.
Olga V. Belyaeva Seung-Ah LeeOleg V. Kolupaev Natalia Y. Kedishvili 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009
Background
In chordates, retinoid metabolism is an important target of short-chain dehydrogenases/reductases (SDRs). It is not known whether SDRs play a role in retinoid metabolism of protostomes, such as Drosophila melanogaster.Methods
Drosophila genome was searched for genes encoding proteins with ∼ 50% identity to human retinol dehydrogenase 12 (RDH12). The corresponding proteins were expressed in Sf9 cells and biochemically characterized. Their phylogenetic relationships were analyzed using PHYLIP software.Results
A total of six Drosophila SDR genes were identified. Five of these genes are clustered on chromosome 2 and one is located on chromosome X. The deduced proteins are 300 to 406 amino acids long and are associated with microsomal membranes. They recognize all-trans-retinaldehyde and all-trans-3-hydroxyretinaldehyde as substrates and prefer NADPH as a cofactor. Phylogenetically, Drosophila SDRs belong to the same branch of the SDR superfamily as human RDH12, indicating a common ancestry early in bilaterian evolution, before a protostome–deuterostome split.Conclusions
Similarities in the substrate and cofactor specificities of Drosophila versus human SDRs suggest conservation of their function in retinoid metabolism throughout protostome and deuterostome phyla.General significance
The discovery of Drosophila retinaldehyde reductases sheds new light on the conversion of β-carotene and zeaxantine to visual pigment and provides a better understanding of the evolutionary roots of retinoid-active SDRs. 相似文献3.
Lister G 《The Yale journal of biology and medicine》2011,84(3):257-268
Dr. George Lister delivered the following presentation as the Lee E. Farr Lecturer on May 8, 2011, which served as the culmination of the annual Student Research Day at Yale School of Medicine. He is the Chair of Pediatrics at the University of Texas Southwestern Medical School and Pediatrician-in-Chief at Children's Medical Center of Dallas. In his lecture to the medical students, who had just completed their research theses, Dr. Lister discusses his own work on sudden infant death syndrome (SIDS), demonstrating the complexity of clinical research and proving insight into the traits required of physician scientists. Committed to medical education and recognized by several awards for his mentorship, he ends the talk by imparting valuable advice on future physicians. 相似文献
4.
Aim: To evaluate possible source of nutrients for bacterial growth within polyurethane (PU) foam of used cot mattresses as determinants of bacterial population density. Methods and Results: Used infant mattresses (n = 30) were analysed for bacteria capable of degrading colloidal PU and for aqueous soluble chemical components (aromatic amines, ammonium ions, phosphates and protein). Mattress type (waterproof cover vs exposed PU foam at the infant‐head region), mattress age and previous use by another child were evaluated as factors that could influence the measured parameters. The levels of protein extracted from PU foam were (i) significantly (P = 0·0019) higher for mattresses lacking a waterproof cover at the infant‐head region and (ii) positively correlated with both culturable bacterial population densities of the PU foams and extent of growth of Staphylococcus aureus on aqueous leachates. No statistically significant (P > 0·05) associations between other measured parameters and mattress type/use factors were identified. Conclusions: Infant use of cot mattresses with exposed PU foam leads to accumulation of proteins within the PU, which can promote bacterial growth. Significance and Impact of the Study: The study provides a mechanistic explanation for increased levels of bacteria associated with exposed PU of cot mattresses. In the context of the common bacterial toxins hypothesis for the sudden infant death syndrome (SIDS), this could explain the lowered risk of SIDS associated with use of a waterproof cover above the mattress. 相似文献
5.
Summary The acyl-CoA dehydrogenases are a family of mitochondrial flavoenzymes required for fatty acid beta-oxidation and branched-chain
amino acid degradation. The hepatic activity of these enzymes, particularly the short-chain acyl-coenzyme A (CoA) dehydrogenase,
is markedly decreased in riboflavin deficient rats. We now report that the in vivo effects of riboflavin deficiency on the
beta-oxidation enzymes of this group are reproduced in FAO rat hepatoma cells cultured in riboflavin-deficient medium. Although
it has been long known that hepatic short-chain acyl-CoA dehydrogenase activity is the most severely affected of the straight-chain
specific enzymes in riboflavin deficiency, the mechanism by which its activity is decreased has not been reported. We have
used this new cell culture system to characterize further this mechanism. Whole cell extracts from riboflavin-deficient and
control cells were subjected to analysis by denaturing polyacrylamide gel electrophoresis. The contents of the gels were then
electroblotted onto nitrocellulose filters and probed with short-chain acyl-CoA dehydrogenase-specific antiserum. The relative
abundance of enzyme antigen was estimated autoradiographically. Our findings indicate that short-chain acyl-CoA dehydrogenase
activity changes in parallel with its antigen, suggesting that riboflavin deprivation does not affect the activity of individual
enzyme molecules. Further, no evidence of extramitochondrial enzyme precursor was found on the blots, making unlikely a significant
block in the mitochondrial uptake process. These findings suggest that changes in short-chain acyl-CoA dehydrogenase activity
in riboflavin deficiency result from either increased synthesis or decreased degradation of the enzyme.
This work was supported by grants from the VA Medical Research Service, the Diabetes Association of Greater Cleveland, and
the National Institutes of Health (HD25299), Bethesda, MD.
Portions of the work presented here were presented at the 71st meeting of the Endocrine Society, Seattle, WA. 相似文献
6.
Yingzhi Xu Fei Sun 《Acta Crystallographica. Section F, Structural Biology Communications》2013,69(5):515-519
3‐Hydroxyacyl‐CoA dehydrogenase (HAD; EC 1.1.1.35) is the enzyme that catalyzes the third step in fatty‐acid β‐oxidation, oxidizing the hydroxyl group of 3‐hydroxyacyl‐CoA to a keto group. The 3‐hydroxyacyl‐CoA dehydrogenase from Caenorhabditis elegans (cHAD) was cloned, overexpressed in Escherichia coli and purified to homogeneity for crystallography. Initial crystals were obtained by the hanging‐drop vapour‐diffusion method. Optimization of the precipitant concentration and the pH yielded two types of well diffracting crystals with parallelepiped and cuboid shapes, respectively. Complete diffraction data sets were collected and processed from both crystal types. Preliminary crystallographic analysis indicated that the parallelepiped‐shaped crystal belonged to space group P1, while the cuboid‐shaped crystal belonged to space group P212121. Analyses of computed Matthews coefficient and self‐rotation functions suggested that there are two cHAD molecules in one asymmetric unit in both crystals, forming identical dimers but packing in distinct manners. 相似文献
7.
Panter MS 《The Yale journal of biology and medicine》2011,84(3):253-255
Dr. George Lister of the University of Texas Southwestern Medical Center delivered the Lee E. Farr Lecture on Student Research Day on May 9, 2011. This day focused on the dissertation work of Yale School of Medicine MD students, whose research opportunities for prospective physicians were recently examined and critiqued by Yale's Committee to Promote Student Interest in Careers as Physician Scientists. Lister's talk served to highlight the importance of communication between the laboratory and the clinic in optimizing diagnostics and treatments, effectively affirming the validity of the Committee's objectives. 相似文献
8.
Jessica L. Tischler Basel Abuaita Sierra C. Cuthpert Christopher Fage Kristi Murphy Andrew Saxe 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):549-555
Butyric acid and trichostatin A (TSA) are anti-cancer compounds that cause the upregulation of genes involved in differentiation and cell cycle regulation by inhibiting histone deacetylase (HDAC) activity. In this study we have synthesized and evaluated compounds that combine the bioavailability of short-chain fatty acids, like butyric acid, with the bidentate binding ability of TSA. A series of analogs were made to examine the effects of chain length, simple aromatic cap groups, and substituted hydroxamates on the compounds' ability to inhibit rat-liver HDAC using a fluorometric assay. In keeping with previous structure-activity relationships, the most effective inhibitors consisted of longer chains and hydroxamic acid groups. It was found that 5-phenylvaleric hydroxamic acid and 4-benzoylbutyric hydroxamic acid were the most potent inhibitors with IC50's of 5 μM and 133 μM respectively. 相似文献
9.
Ann E Gordon Osama Al Madani Donald M Weir Anthony Busuttil Caroline Blackwell 《FEMS immunology and medical microbiology》1999,25(1-2):199-206
There is evidence that inflammatory responses have been induced in the tissues and body fluids of many SIDS infants. We suggested that some of these deaths are due to uncontrolled inflammatory responses to infectious agents and possibly cigarette smoke. The majority of SIDS deaths occur during the 2-4 month age range when infants have decreasing levels of maternal antibodies to infectious agents. Most deaths occur during the early hours of the morning. Adults are more susceptible to inflammatory responses at night due to lower levels of cortisol associated with circadian rhythm patterns. Infants develop these patterns between the ages of 7 weeks and 4 months, at which time their night-time cortisol levels drop dramatically. The objective of this study was to use an in vitro model system to assess the effects of different cortisol levels on proinflammatory cytokine production in response to the staphylococcal toxic shock syndrome toxin-1 (TSST-1) which has been identified in a significant number of SIDS infants. Levels of cortisol present in infants at night and during the day before and after the development of the circadian rhythm pattern were examined. Human buffy coats (n = 9) were stimulated with TSST-1 and responses assessed over 72 hours by a bioassay for tumour necrosis factor-alpha (TNF-alpha) and an enzyme linked immunosorbent assay (ELISA) for interleukin-6 (IL-6). Cortisol levels present in an infant at night after development of circadian rhythm (< or = 5 microg dl(-1)), did not significantly increase or decrease production of either TNF-alpha or IL-6. Concentrations of cortisol greater than 5 microg dl(-1) usually found in infants during the day or at night prior to the physiological change significantly decreased production of TNF-alpha at 12 hours and of IL-6 at 12 and 16 hours. Only cortisol levels greater than 5 microg dl(-1) significantly decreased production of the pro-inflammatory cytokines by human buffy coats stimulated with TSST-1. If the switch to the circadian rhythm pattern occurs in an infant when maternal antibodies are still present or after they have developed their own active immunity, the infant could neutralise common viruses, toxins or bacteria: however, if this switch occurs in an infant when antibody levels are low, this could be a window of vulnerability during which infants are at an increased risk of death if uncontrolled inflammatory responses are induced by infectious agents or their products. 相似文献
10.
《Archives of animal nutrition》2013,67(2):170-179
Abstract The experiment was conducted to investigate the effects of different inclusion levels of extruded corn on growth performance, nutrient digestibility and short-chain fatty acids profiles in the hindgut of weaned piglets. Ninety weaning piglets (28 d of age; 8.21 ± 0.69 kg BW) were allotted to one of five dietary treatments only substituted for unprocessed corn at varying levels (0, 1/4, 2/4, 3/4, 4/4) with extruded corn in a 28-d experiment. On day 28, 30 piglets were killed to measure concentrations and molar ratios of short-chain fatty acids in the hindgut. From day 0 – 14, digestibility of DM, N and GE was increased linearly and diarrhea frequency was decreased due to the increasing inclusion levels of extruded corn. From day 14 – 28, digestibility of GE and N was enhanced linearly due to the increasing proportion of extruded corn. On day 28, as proportion of extruded corn increased, the level of butyrate in the caecum and colon was increased linearly and the relative proportion of propionate was reduced. Results indicated that increasing proportions of extruded corn had no effect on growth performance, but significantly improved digestibility of N and energy at day 10 of trial and may be advantageous to the intestinal health of piglets. 相似文献
11.
Growth and survival of bacteria implicated in sudden infant death syndrome on cot mattress materials
AIMS: To compare growth and survival of selected bacteria implicated in sudden infant death syndrome (SIDS) on cot mattress polyurethane (PU) inner-foams and on different types of cot mattress cover materials. METHODS AND RESULTS: Escherichia coli, Staphylococcus aureus or Streptococcus pyogenes were inoculated onto swatches of new-unused cot mattress PU inner-foam and onto three types of cot mattress covers (polyvinyl chloride, cotton and polyester). The influence of inoculation cell density, relative humidity (RH) and temperature of incubation on survival was assessed by recovery of cells in 0.85% NaCl, with viable cell enumeration by plate counting on selective and differential media. Utilization of carbon and nitrogen sources within cot mattress PU was assessed by following growth on aqueous leachate from PU, and by colorimetric determination of aromatic amines. Good survival capability (>206 d) was shown by all three test species on PU inner-foam and on polyester mattress cover at high RH (75%), but only by Staph. aureus on PU at low RH (25%). Aqueous soluble material from PU foam supports bacterial growth; removal of aromatic amines from aqueous leachate from PU accompanies growth of Staph. aureus. CONCLUSIONS: Staphylococcus aureus has good survival capability on cot mattress PU foam, even at low RH. Soluble material within PU can serve as carbon and nitrogen sources for bacterial growth. SIGNIFICANCE AND IMPACT OF THE STUDY: Prolonged survival of Staph. aureus on PU at low RH could explain, in the context of the common bacterial toxins hypothesis, an increased risk of SIDS associated with used infant mattresses. 相似文献
12.
It has been proposed that in some anaerobic facultatively autotrophic bacteria the acetyl CoA/CO dehydrogenase pathway is operating both in the reductive and in the oxidative direction, depending on the growth conditions. One of these anaerobes, the Gram-negative sulfate-reducing cubacterium Desulfobacterium autotrophicum, was examined for enzymes of the proposed pathway. All the required enzyme activities were present in sufficient amounts both in autotrophically and in heterotrophically grown cells, provided that the cellular tetrahydropterin rather than tetrahydrofolate was used as cosubstrate in some of the enzyme assays. The question arises whether two sets of enzymes are operating in the reductive and oxidative direction, respectively. The key enzyme of this pathway, CO dehydrogenase, which was reasonably oxygen stable, was analysed by native polyacrylamide gel electrophoresis and anaerobic activity staining. Extracts from heterotrophically grown cells exhibited five enzyme activity bands. Extracts from autotrophically grown cells showed the same pattern but an additional activity band appeared. 相似文献
13.
Highet AR 《Journal of applied microbiology》2008,105(3):625-635
Due attention has been given to infectious agents and immune responses to infection in sudden infant death syndrome (SIDS). It has been acknowledged that the pathological, epidemiological and genotypic findings in SIDS infants suggest an infectious aetiology possibly being potentiated by immunoregulatory polymorphisms, however, the cause of SIDS is a mystery and remains open to debate. Consistent pathological findings are seen which display similarities to the pathogenesis of toxaemic shock and/or sepsis. The major risk factors for SIDS parallel those for increased colonization and serious bacterial infections and the natural variation in the incidence of SIDS cases is typical of an infectious disease. The roles played by viral infection, immunoregulatory genes and suspected bacterial species are discussed herein. 相似文献
14.
V. Bernal P. Arense V. Blatz M.A. Mandrand-Berthelot M. Cánovas J.L. Iborra 《Journal of applied microbiology》2008,105(1):42-50
Aims: Characterization of the role of CaiC in the biotransformation of trimethylammonium compounds into l (−)-carnitine in Escherichia coli .
Methods and Results: The caiC gene was cloned and overexpressed in E. coli and its effect on the production of l (−)-carnitine was analysed. Betaine:CoA ligase and CoA transferase activities were analysed in cell free extracts and products were studied by electrospray mass spectrometry (ESI-MS). Substrate specificity of the caiC gene product was high, reflecting the high specialization of the carnitine pathway. Although CoA-transferase activity was also detected in vitro , the main in vivo role of CaiC was found to be the synthesis of betainyl-CoAs. Overexpression of CaiC allowed the biotransformation of crotonobetaine to l (−)-carnitine to be enhanced nearly 20-fold, the yield reaching up to 30% (with growing cells). Higher yields were obtained using resting cells (up to 60%), even when d (+)-carnitine was used as substrate.
Conclusions: The expression of CaiC is a control step in the biotransformation of trimethylammonium compounds in E. coli .
Significance and Impact of the Study: A bacterial betaine:CoA ligase has been characterized for the first time, underlining its important role for the production of l -carnitine with Escherichia coli . 相似文献
Methods and Results: The caiC gene was cloned and overexpressed in E. coli and its effect on the production of l (−)-carnitine was analysed. Betaine:CoA ligase and CoA transferase activities were analysed in cell free extracts and products were studied by electrospray mass spectrometry (ESI-MS). Substrate specificity of the caiC gene product was high, reflecting the high specialization of the carnitine pathway. Although CoA-transferase activity was also detected in vitro , the main in vivo role of CaiC was found to be the synthesis of betainyl-CoAs. Overexpression of CaiC allowed the biotransformation of crotonobetaine to l (−)-carnitine to be enhanced nearly 20-fold, the yield reaching up to 30% (with growing cells). Higher yields were obtained using resting cells (up to 60%), even when d (+)-carnitine was used as substrate.
Conclusions: The expression of CaiC is a control step in the biotransformation of trimethylammonium compounds in E. coli .
Significance and Impact of the Study: A bacterial betaine:CoA ligase has been characterized for the first time, underlining its important role for the production of l -carnitine with Escherichia coli . 相似文献
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Helen Skilling Liane Fairfull Bret H. Goodpaster Eric S. Goetzman 《Biochemical and biophysical research communications》2010,400(3):318-322
Brown adipose tissue is a highly specialized organ that uses mitochondrial fatty acid oxidation to fuel non-shivering thermogenesis. In mice, mutations in the acyl-CoA dehydrogenase family of fatty acid oxidation genes are associated with sensitivity to cold. Brown adipose tissue function has not previously been characterized in these knockout strains. Short-chain acyl-CoA dehydrogenase (SCAD) deficient mice were found to have increased brown adipose tissue mass as well as modest cardiac hypertrophy. Uncoupling protein-1 was reduced by 70% in brown adipose tissue and this was not due to a change in mitochondrial number, nor was it due to decreased signal transduction through protein kinase A which is known to be a major regulator of uncoupling protein-1 expression. PKA activity and in vitro lipolysis were normal in brown adipose tissue, although in white adipose tissue a modest increase in basal lipolysis was seen in SCAD−/− mice. Finally, an in vivo norepinephrine challenge of brown adipose tissue thermogenesis revealed normal heat production in SCAD−/− mice. These results suggest that reduced brown adipose tissue function is not the major factor causing cold sensitivity in acyl-CoA dehydrogenase knockout strains. We speculate that other mechanisms such as shivering capacity, cardiac function, and reduced hepatic glycogen stores are involved. 相似文献
17.
Chen ZJ Pudas R Sharma S Smart OS Juffer AH Hiltunen JK Wierenga RK Haapalainen AM 《Journal of molecular biology》2008,379(4):830-844
Structural and kinetic properties of the human 2-enoyl thioester reductase [mitochondrial enoyl-coenzyme A reductase (MECR)/ETR1] of the mitochondrial fatty acid synthesis (FAS) II pathway have been determined. The crystal structure of this dimeric enzyme (at 2.4 Å resolution) suggests that the binding site for the recognition helix of the acyl carrier protein is in a groove between the two adjacent monomers. This groove is connected via the pantetheine binding cleft to the active site. The modeled mode of NADPH binding, using molecular dynamics calculations, suggests that Tyr94 and Trp311 are critical for catalysis, which is supported by enzyme kinetic data. A deep, water-filled pocket, shaped by hydrophobic and polar residues and extending away from the catalytic site, was recognized. This pocket can accommodate a fatty acyl tail of up to 16 carbons. Mutagenesis of the residues near the end of this pocket confirms the importance of this region for the binding of substrate molecules with long fatty acyl tails. Furthermore, the kinetic analysis of the wild-type MECR/ETR1 shows a bimodal distribution of catalytic efficiencies, in agreement with the notion that two major products are generated by the mitochondrial FAS II pathway. 相似文献
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