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21.
1. Rat liver microsomal stearoyl-CoA desaturase activity was shown to be stimulated by both bovine serum albumin and a basic cytoplasmic protein from rat liver. 2. Partially purified desaturase is unaffected by either of these two proteins. 3. Bovine serum albumin appears to exert its effect on the crude system by protecting the desaturase substrate, stearoly-CoA, from the action of endogenous thiolesterases. 4. By using partially purified enzyme preparations, it was possible to establish the substate specificity of the delta9-fatty acyl-CoA desaturase with the C14, C15, C16, C17, C18 and C19 fatty acyl-CoA substrates. Maximum enzyme activity was shown with stearoyl-CoA decreasing with both palmitoyl-CoA and nonadecanoyl-CoA, as reported previously for free fatty acids. 5. Both cytochrome b5 and NADH-cytochrome b5 reductase (EC 1.6.2.2) are required for these studies and a method is described for the purification of homogeneous preparations of detergent-isolated cytochrome b5 from rat liver. 6. From amino acid analyses, a comparison was made of the hydrophobicity of the membrane portion of cytochrome b5 with the hydrophobicity reported for stearoyl-CoA desaturase. The close resemblance of the two values suggested that unlike cytochrome b5 and its reductase, the stearoyl-CoA desaturase may be largely buried in the endoplasmic reticulum. 相似文献
22.
1. The influence of bovine serum albumin and soluble rat liver proteins on the activity of rat liver microsomal delta9 and delta6 desaturases has been studied. 2. In the absence of bovine serum albumin, the delta9 desaturase which converts stearoyl-CoA into oleoyl-CoA, shows a non-linear correlation between enzyme activity and protein concentration. 3. Optimum concentrations of bovine serum albumin have three main effects on the enzyme activity: (i) establishes a linear relationship between enzyme activity and protein concentration, (ii) stimulates the enzyme activity 2--3-fold and (iii) raises the optimum substrate concentration from 10 to 100 muM. 4. A highly purified soluble liver protein of molecular weight 24 000 also stimulated the enzyme activity and brought about a linear relationship between enzyme activity and protein concentration. 5. It was concluded that the non-linear kinetics were due to limiting amounts of substrate binding protein in the microsomal preparations. 6. The delta6 desaturase which converts linoleoyl-CoA into gamma-linolenoyl-CoA was also stimulated by bovine serum albumin and soluble liver proteins. 7. The significance of the fatty acid-binding proteins is discussed. 相似文献
23.
Dhanashree?A?Paranjpe D?Anitha MK?Chandrashekaran Amitabh?Joshi Vijay?Kumar?SharmaEmail author 《BMC developmental biology》2005,5(1):5
Background
In insects, circadian clocks have been implicated in affecting life history traits such as pre-adult development time and adult lifespan. Studies on the period (per) mutants of Drosophila melanogaster, and laboratory-selected lines of Bactrocera cucurbitae suggested a close link between circadian clocks and development time. There is a possibility of clock genes having pleiotropic effects on clock period and pre-adult development time. In order to avoid such pleiotropic effects we have used wild type flies of same genotype under environments of different periodicities, which phenotypically either speeded up or slowed down the eclosion clock of D. melanogaster. 相似文献24.
MK Parr F Botrè A Na? J Hengevoss P Diel G Wolber 《Biology of sport / Institute of Sport》2015,32(2):169-173
Increasing numbers of dietary supplements with ecdysteroids are marketed as “natural anabolic agents”. Results of recent studies suggested that their anabolic effect is mediated by estrogen receptor (ER) binding. Within this study the anabolic potency of ecdysterone was compared to well characterized anabolic substances. Effects on the fiber sizes of the soleus muscle in rats as well the diameter of C2C12 derived myotubes were used as biological readouts. Ecdysterone exhibited a strong hypertrophic effect on the fiber size of rat soleus muscle that was found even stronger compared to the test compounds metandienone (dianabol), estradienedione (trenbolox), and SARM S 1, all administered in the same dose (5 mg/kg body weight, for 21 days). In C2C12 myotubes ecdysterone (1 µM) induced a significant increase of the diameter comparable to dihydrotestosterone (1 µM) and IGF 1 (1.3 nM). Molecular docking experiments supported the ERβ mediated action of ecdysterone. To clarify its status in sports, ecdysterone should be considered to be included in the class “S1.2 Other Anabolic Agents” of the list of prohibited substances of the World Anti-Doping Agency. 相似文献
25.
Muhammad Nasir Nafees Ahmad Christian MK Sieber Amir Latif Salman Akbar Malik Abdul Hameed 《Journal of biomedical science》2013,20(1):70
Background
Xeroderma Pigmentosum (XP) is a rare skin disorder characterized by skin hypersensitivity to sunlight and abnormal pigmentation. The aim of this study was to investigate the genetic cause of a severe XP phenotype in a consanguineous Pakistani family and in silico characterization of any identified disease-associated mutation.Results
The XP complementation group was assigned by genotyping of family for known XP loci. Genotyping data mapped the family to complementation group A locus, involving XPA gene. Mutation analysis of the candidate XP gene by DNA sequencing revealed a novel deletion mutation (c.654del A) in exon 5 of XPA gene. The c.654del A, causes frameshift, which pre-maturely terminates protein and result into a truncated product of 222 amino acid (aa) residues instead of 273 (p.Lys218AsnfsX5). In silico tools were applied to study the likelihood of changes in structural motifs and thus interaction of mutated protein with binding partners. In silico analysis of mutant protein sequence, predicted to affect the aa residue which attains coiled coil structure. The coiled coil structure has an important role in key cellular interactions, especially with DNA damage-binding protein 2 (DDB2), which has important role in DDB-mediated nucleotide excision repair (NER) system.Conclusions
Our findings support the fact of genetic and clinical heterogeneity in XP. The study also predicts the critical role of DDB2 binding region of XPA protein in NER pathway and opens an avenue for further research to study the functional role of the mutated protein domain. 相似文献26.
Anthony A Fryer Richard D Emes Khaled MK Ismail Kim E Haworth Charles Mein William D Carroll William E Farrell 《Epigenetics》2011,6(1):86-94
Supplementation with folic acid during pregnancy is known to reduce the risk of neural tube defects and low birth weight. It is thought that folate and other one-carbon intermediates might secure these clinical effects via DNA methylation. We examined the effects of folate on the human methylome using quantitative interrogation of 27,578 CpG loci associated with 14,496 genes at single-nucleotide resolution across 12 fetal cord blood samples. Consistent with previous studies, the majority of CpG dinucleotides located within CpG islands exhibited hypomethylation while those outside CpG islands showed mid-high methylation. However, for the first time in human samples, unbiased analysis of methylation across samples revealed a significant correlation of methylation patterns with plasma homocysteine, LINE-1 methylation and birth weight centile. Additionally, CpG methylation significantly correlated with either birth weight or LINE-1 methylation were predominantly located in CpG islands. These data indicate that levels of folate-associated intermediates in cord blood reflect their influence and consequences for the fetal epigenome and potentially on pregnancy outcome. In these cases, their influence might be exerted during late gestation or reflect those present during the peri-conceptual period.Key words: cord blood, birth weight, folic acid, homocysteine, BeadArray, hierarchical clustering, Illumina 相似文献
27.
M Küüsmaa-Schildt J Liukkonen MK Vuong K Nyman K Häkkinen A Häkkinen 《Chronobiology international》2019,36(6):811-825
The aim of the present study was to examine how combined strength and endurance training in the morning and evening influences the adaptations in strength and endurance performance, perception of time management, psychological well-being and sleep. The combined training period lasted for 24 weeks and the participants were divided into the morning training (MG, n = 18), evening training (EG, n = 24) and control groups (CG, n = 10). Isometric leg press force (iLP), maximal oxygen consumption (VO2max), sleep behavior, fatigue, time management, motivation, self-esteem and health-related quality of life (HRQoL) were assessed. Morning to evening difference in iLP was observed in both MG and EG at Pre and Post, with higher force values in the evening, but not for VO2max. iLP force increased significantly in EG in the morning (p < 0.001) and evening (p = 0.010). VO2max increased in MG and EG both in the morning (both p < 0.001) and in the evening (MG: p < 0.001; EG: p = 0.003). Participants of the present study slept 7–8 h per night and the self-reported sleep duration, get-up time and the average time to go to bed were similar between the groups and did not change from Pre to Post. From HRQoL dimensions, the score for bodily pain decreased in MG (p = 0.029) and significant between-group differences were observed for Pre-Post changes in MG and EG (p = 0.001) as well as between MG and CG (p < 0.001). In vitality, a significant between-group difference was observed for Pre to Post changes in MG and EG (p = 0.014). Perception of time management decreased in EG (p = 0.042) but stayed unchanged for MG and CG. For the intrinsic motivation to participate, significant between-group differences were observed for MG and EG (p = 0.033) and between MG and CG (p = 0.032) for Pre to Post changes. Self-esteem improved in MG (p = 0.029) and EG (p = 0.024). The present combined strength and endurance training program performed in the morning and in the evening led to similar improvements in strength and endurance performance. Training in the morning or in the evening did not disrupt the already good sleep behavior and it was able to further increase the self-esteem. Although training in the morning hours may leave more time for free time activities or social life (i.e. family and friends) compared to the evening training, it might be more challenging to stay motivated to participate in prolonged training programs in the morning hours. 相似文献
28.
29.
目前几乎所有有机化学品和塑料是从原油和天然气中生产的, 而生物技术的应用使得利用可再生资源进行大规模化工生产成为可能。以下主要综述了白色生物技术, 即利用细菌、酵母或酶将可发酵糖转化为特定的化学产品的技术。白色生物技术极大节省了不可再生能源的消耗, 减少了温室气体的排放。在有利条件下, 如果化工生产中相关技术有了发展并且可以成功以木质纤维素为原料, 那么到2050年不可再生能源的消耗将减少将近2/3 (67%)。欧洲(EU-25)地区的分析表明, 白色生物技术相关的用地在未来几年的欧洲不会受到制约, 尤其是有大量闲置资源的东欧。另外, 虽然原则上可以在白色生物技术中使用自然的细菌和酶, 但是很多专家认为, 利用经遗传改造生物体(GMO)可以达到高产量、高浓度、高效率, 这对实现经济活力是必要的。值得注意的是, 目前并不是所有的重组基因和其他物种间的相互作用所带来的后果都可预见, 因此化工生产释放的GMOs的安全失活和处理非常重要, 但是如果采取足够的预防措施, 在白色生物技术中应用GMOs的风险是可以控制的。我们认为, 生物生产过程的技术突破、下游生产过程的控制、化石燃料的高价格、可发酵糖的低价获得是生物质化学产业发展中的关键因素, 这4个因素及其他伴随策略是发展整体白色生物技术的要求。 相似文献
30.
OLF Weyl MK Schirrmann JS Hargrove T Bodill ER Swartz 《African Journal of Aquatic Science》2017,42(4):359-365
Largemouth bass Micropterus salmoides are a popular North American angling species that was introduced into South Africa in 1928. To enhance the largemouth bass fisheries, Florida bass Micropterus floridanus were introduced into KwaZulu Natal, South Africa, in 1980. Knowledge on the status of M. floridanus in South Africa is required, because it lives longer and reaches larger sizes than M. salmoides, which may result in heightened impacts on native biota. Because M. floridanus are morphologically similar, but genetically distinct from M. salmoides, the distribution of this species was assessed by genetically screening 185 Micropterus sp. individuals sampled from 20 localities across South Africa using the mitochondrial ND2 gene. Individuals with mitochondrial DNA matching M. salmoides were recovered from 16 localities, whereas M. floridanus mitochondrial DNA was recovered from 13 localities. At nine localities (45%), the mitochondrial DNA of both species was detected. These results demonstrate M. floridanus dispersal to multiple sites across South Africa. 相似文献