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101.
Cysteine 195 in isocitrate lyase from Escherichia coli has been replaced by directed mutagenesis. Substitution by Ser yields enzyme with a kcat that is 0.03% that of wild type, and substitution by Ala, Gly, Thr, or Val yields completely inactive enzyme. The present
results are consistent with a functional role of Cys 195.
Received: 26 March 1997 / Accepted: 29 April 1997 相似文献
102.
Mujahid Iqbal Hui Zhang Khalid Mehmood Aoyun Li Xiong Jiang Yaping Wang Jialu Zhang Muhammad Kashif Iqbal Mujeeb Ur Rehman Wangyuan Yao Shijin Yang Jiakui Li 《Biological procedures online》2018,20(1):15
Background
Tibial dyschondroplasia (TD) is a skeletal disease of fast growing chicken and other avian species. It is characterized by an avascular and non-mineralized growth plate, which leads to a deformed tibial bone and lameness. Unfortunately, this disease is not only responsible for causing huge economic losses but also raises animal welfare concerns. Icariin is a flavonoid, which is isolated from Epimedium pubescens herb, and it has been used to cure different diseases including bone fractures and osteoporosis.Results
We designed this experiment to use icariin for the treatment of TD affect chickens; for this purpose, a total of 180 chicks were equally divided into three groups: control, TD and icariin. All the three groups were offered ad libitum same normal standard diet with an addition of thiram (50 mg/kg) from 3rd day to 7th day in TD and icariin group in order to induce TD in chickens. After the induction of TD, the chickens in icariin groups were fed standard diet with an addition of icariin at the rate of 10 mg/kg in drinking water to check the therapeutic effect of this flavonoid on TD. Our results showed that the icariin helped in restoring the TD lesion into a normal structure with significantly (P?<?0.05) up-regulating the bone morphogenetic protein-2 (BMP-2) expression in the tibial growth plates (GP).Conclusions
Icariin increased the vascular area in the growth plate and decreased the average TD score. In conclusion, this study shows that icariin is a potential compound for the recovery of TD affected chickens via up-regulating the BMP-2 expression without posing a threat of ingestion of toxic veterinary drug residues to human beings upon the consumption of treated chickens.103.
Seyed Fazel Nabavi Antoni Sureda Ahmad Reza Dehpour Samira Shirooie Ana Sanches Silva Kasi Pandima Devi Touqeer Ahmed Nafeesa Ishaq Rabia Hashim Eduardo Sobarzo-Sánchez Maria Daglia Nady Braidy Mariateresa Volpicella Rosa Anna Vacca Seyed Mohammad Nabavi 《Biotechnology advances》2018,36(6):1768-1778
In the present paper, we will discuss on the importance of autophagy in the central nervous system, and outline the relation between autophagic pathways and the pathogenesis of neurodegenerative disorders. The potential therapeutic benefits of naturally occurring phytochemicals as pharmacological modulators of autophagy will also be addressed. Our findings provide renewed insight on the molecular modes of protection by polyphenols, which is likely to be at least in part mediated not only by their potent antioxidant and anti-inflammatory effects, but also through modulation of autophagic processes to remove the aberrant protein aggregates. 相似文献
104.
Hye-Rim Shin Rabia Islam Won-Joon Yoon Taegyung Lee Young-Dan Cho Han-sol Bae Bong-Su Kim Kyung-Mi Woo Jeong-Hwa Baek Hyun-Mo Ryoo 《The Journal of biological chemistry》2016,291(11):5555-5565
The canonical Wnt signaling pathway, in which β-catenin nuclear localization is a crucial step, plays an important role in osteoblast differentiation. Pin1, a prolyl isomerase, is also known as a key enzyme in osteogenesis. However, the role of Pin1 in canonical Wnt signal-induced osteoblast differentiation is poorly understood. We found that Pin1 deficiency caused osteopenia and reduction of β-catenin in bone lining cells. Similarly, Pin1 knockdown or treatment with Pin1 inhibitors strongly decreased the nuclear β-catenin level, TOP flash activity, and expression of bone marker genes induced by canonical Wnt activation and vice versa in Pin1 overexpression. Pin1 interacts directly with and isomerizes β-catenin in the nucleus. The isomerized β-catenin could not bind to nuclear adenomatous polyposis coli, which drives β-catenin out of the nucleus for proteasomal degradation, which consequently increases the retention of β-catenin in the nucleus and might explain the decrease of β-catenin ubiquitination. These results indicate that Pin1 could be a critical target to modulate β-catenin-mediated osteogenesis. 相似文献
105.
Revisiting Kadenbach: Electron flux rate through cytochrome c‐oxidase determines the ATP‐inhibitory effect and subsequent production of ROS 下载免费PDF全文
Sebastian Vogt Annika Rhiel Petra Weber Rabia Ramzan 《BioEssays : news and reviews in molecular, cellular and developmental biology》2016,38(6):556-567
Mitochondrial respiration is the predominant source of ATP. Excessive rates of electron transport cause a higher production of harmful reactive oxygen species (ROS). There are two regulatory mechanisms known. The first, according to Mitchel, is dependent on the mitochondrial membrane potential that drives ATP synthase for ATP production, and the second, the Kadenbach mechanism, is focussed on the binding of ATP to Cytochrome c Oxidase (CytOx) at high ATP/ADP ratios, which results in an allosteric conformational change to CytOx, causing inhibition. In times of stress, ATP‐dependent inhibition is switched off and the activity of CytOx is exclusively determined by the membrane potential, leading to an increase in ROS production. The second mechanism for respiratory control depends on the quantity of electron transfer to the Heme aa3 of CytOx. When ATP is bound to CytOx the enzyme is inhibited, and ROS formation is decreased, although the mitochondrial membrane potential is increased. 相似文献
106.
Jaspreet Kaur Dhanjal Sukriti Goyal Sudhanshu Sharma Rabia Hamid Abhinav Grover 《Biochemical and biophysical research communications》2014
Alzheimer’s is a neurodegenerative disorder resulting in memory loss and decline in cognitive abilities. Accumulation of extracellular beta amyloidal plaques is one of the major pathology associated with this disease. β-Secretase or BACE-1 performs the initial and rate limiting step of amyloidic pathway in which 37–43 amino acid long peptides are generated which aggregate to form plaques. Inhibition of this enzyme offers a viable prospect to check the growth of these plaques. Numerous efforts have been made in recent years for the generation of BACE-1 inhibitors but many of them failed during the preclinical or clinical trials due to drug related or drug induced toxicity. In the present work, we have used computational methods to screen a large dataset of natural compounds to search for small molecules having BACE-1 inhibitory activity with low toxicity to normal cells. Molecular dynamics simulations were performed to analyze molecular interactions between the screened compounds and the active residues of the enzyme. Herein, we report two natural compounds of inhibitory nature active against β-secretase enzyme of amyloidic pathway and are potent lead molecules against Alzheimer’s disease. 相似文献
107.
This study was designed to evaluate the efficacy of Buffalo Rat Liver cells (BRLC) monolayers in supporting the development of in vitro matured and fertilized (IVM/IVF) bovine oocytes through to the hatched blastocyst stage compared to the commonly used co-culture system of bovine oviduct epithelial cells (BOEC). Cumulus oocyte complexes (COCs) obtained from 2- to 6-mm ovarian follicles at slaughter were matured for 24 h in TCM-199 supplemented with FBS and hormones (FSH, LH and estradiol 17-beta). In vitro fertilization (IVF) was performed using 1 x 10(6) percoll separated frozen-thawed spermatozoa in 1 ml of IVF-TL medium containing 18 to 20 matured oocytes. After 20 to 22 h of sperm exposure, 584 presumptive zygotes in 2 separate trials were randomly assigned to 3 treatment groups (BRLC co-culture, BOEC co-culture and control, consisting of medium alone). Zygotes were cultured in CZB media, a simple semi-defined medium, without glucose for the first 2 d, transferred to M199/FBS (TCM-199-HEPES supplemented with 20% HTFBS, 1 mM Sodium pyruvate), and cultured for an additional 8 days. Cleavage and development to morula and various blastocyst stages were recorded between d 3 and 11 after the start of IVF. Overall average cleavage rate was 75% (440 584 ) and did not vary across the treatments or trials. The proportion of embryos that reached the morula stage in both co-culture systems did not differ (P > 0.05) and was significantly higher (P > 0.05) compared to the control group. However, the percentage of the number of blastocysts, expanded blastocysts and hatched blastocysts varied across the treatment groups (P < 0.05), with the highest results obtained in the BRLC co-culture system. The production of blastocysts in BOEC co-culture was inconsistent between the 2 trials where a significant difference (40.6 vs 53.0%; P > 0.05) was observed. Rate of development to the blastocyst stage was similar between the 2 co-culture systems, with most of the embryos reaching the blastocyst stage by d 8 post insemination. The results of this study show that BRLC from a commercially available established cell line offer a more reliable alternative to a BOEC co-culture system for in vitro maturation, fertilization and culture of bovine embryos. 相似文献
108.
109.
110.
Bleavins K Perone P Naik M Rehman M Aslam MN Dame MK Meshinchi S Bhagavathula N Varani J 《Biological trace element research》2012,145(2):257-267
The purpose of this study was to assess insoluble salts containing gadolinium (Gd3+) for effects on human dermal fibroblasts. Responses to insoluble Gd3+ salts were compared to responses seen with Gd3+ solubilized with organic chelators, as in the Gd3+-based contrast agents (GBCAs) used for magnetic resonance imaging. Insoluble particles of either Gd3+ phosphate or Gd3+ carbonate rapidly attached to the fibroblast cell surface and stimulated proliferation. Growth was observed at Gd3+ concentrations between 12.5 and 125 μM, with toxicity at higher concentrations. Such a narrow window did not characterize
GBCA stimulation. Proliferation induced by insoluble Gd3+ salts was inhibited in the presence of antagonists of mitogen-activated protein kinase and phosphatidylinositol 3-kinase
signaling pathways (similar to chelated Gd3+) but was not blocked by an antibody to the platelet-derived growth factor receptor (different from chelated Gd3+). Finally, high concentrations of the insoluble Gd3+ salts failed to prevent fibroblast lysis under low-Ca2+ conditions, while similar concentrations of chelated Gd3+ were effective. In conclusion, while insoluble Gd3+ salts are capable of stimulating fibroblast proliferation, one should be cautious in assuming that GBCA dechelation must
occur in vivo to produce the profibrotic changes seen in association with GBCA exposure in the subset of renal failure patients
that develop nephrogenic systemic fibrosis. 相似文献