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1.
Cell J ; 21(4): 479-493, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31376330

ABSTRACT

OBJECTIVE: Testing novel biomaterials for the three dimensional (3D) culture of ovarian follicles may ultimately lead to a culture model which can support the integrity of follicles during in vitro culture (IVC). The present study reports the first application of a chitosan (CS) hydrogel in culturing mouse preantral follicles. MATERIALS AND METHODS: In this interventional experiment study, CS hydrogels with the concentrations of 0.5, 1, and 1.5% were first tested for fourier transform infrared spectroscopy (FT-IR), Compressive Strength, viscosity, degradation, swelling ratio, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity and live/dead assay. Thereafter, mouse ovarian follicles were encapsulated in optimum concentration of CS (1%) and compared with those in alginate hydrogel. The follicular morphology, quality of matured oocyte and steroid secretion in both CS and alginate were assessed by enzyme-linked immunosorbent assay (ELISA). The expression of folliculogenesis, endocrine, and apoptotic related genes was also evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and compared with day that in 0. RESULTS: The rates of survival, and diameter of the follicles, secretion of estradiol, normal appearance of meiotic spindle and chromosome alignment were all higher in CS group compared with those in alginate group (P≤0.05). The expression of Cyp19a1 and Lhcgr in CS group was significantly higher than that of the alginate group (P≤0.05). CONCLUSION: The results showed that CS is a permissive hydrogel and has a beneficial effect on encapsulation of ovarian follicle and its further development during 3D culture.

2.
Int J Fertil Steril ; 12(3): 235-241, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29935070

ABSTRACT

BACHGROUND: Hypoxia causes detrimental effects on the structure and function of tissues through increased production of reactive oxygen species that are generated during the re-oxygenation phase of intermittent and continuous hypobaric hypoxia. This study was carried out to evaluate the effects of flaxseed (Fx) in reducing the incidence of hypoxia in rat testes. MATERIALS AND METHODS: In this experimental study, 24 adult Wistar rats were randomly divided into four groups: i. Control group (Co) that received normal levels of oxygen and food, ii. Sham group (Sh) that were placed in hypoxia chamber but received normal oxygen and food, iii. Hypoxia induction group (Hx) that were placed in hypoxia chamber and treated with normal food, iv. Hypoxia induction group (Hx+Fx) that were placed in hypoxia chamber and treated with 10% flaxseed food. Both the Hx and Hx+Fx groups were kept in a hypoxic chamber for 30 days; during this period rats were exposed to reduced pressure (oxygen 8% and nitrogen 92%) for 4 hours/day. Then, all animal were sacrificed and their testes were removed. Malondialdehyde (MDA) and total antioxidant capacity (TAC) levels were evaluated in the testis tissue. Tubular damages were examined using histological studies. Blood samples and sperm were collected to assess IL-18 level and measure sperms parameters, respectively. All data were analyzed using SPPSS-22 software. One way-ANOVA or Kruskal-Wallis tests were performed for statistical analysis. RESULTS: A significant difference was recorded in the testicular mass/body weight ratio in Hx and Hx+Fx groups in comparison to the control (P=0.003 and 0.027, respectively) and Sh (P=0.001 and 0.009, respectively) groups. The sperm count and motility in Hx+Fx group were significantly different from those of the Hx group (P=0.0001 and 0.028, respectively) .Also sperm viability (P=0.0001) and abnormality (P=0.0001) in Hx+Fx group were significantly different from Hx group. CONCLUSION: This study therefore suggests that the oral administration of flaxseed can be useful for prevention from the detrimental effects of hypoxia on rat testes structure and sperm parameters.

3.
Forensic Sci Int ; 260: 27-30, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26795396

ABSTRACT

Estimation of stature is an important issue, which is significantly considered in forensic anthropology. It will be difficult to predict the identification of an individual when only some parts of dead body are discovered following disasters or criminal events. The aim of this study was to assess the relationship between stature and upper limb and hand length in Iranian adults to generate regression formulae for stature estimation. Three anthropometric measurements; Stature, Upper Limb Length (ULL) and Hand Length (HL) were taken on subjects, comprising 142 male students (18-25 years) using standard measuring instruments. The data were analysed using SPSS 16. Then linear regression models were used to estimate stature. The results indicated a positive correlation between stature and upper limb and hand measurements. The correlation coefficient with upper limb length was r = 0.89 & p = 0.0001 and with hand length was r = 0.78 & p = 0.0001. In conclusion, we found a strong correlation between stature and upper limb and hand length. The regression analysis also showed that the Upper Limb Length give better prediction of stature compared to Hand length measurements.


Subject(s)
Body Height , Hand/anatomy & histology , Upper Extremity/anatomy & histology , Adolescent , Adult , Forensic Anthropology/methods , Humans , Iran , Linear Models , Male , Young Adult
4.
Cell Death Dis ; 6: e1837, 2015 Aug 06.
Article in English | MEDLINE | ID: mdl-26247723

ABSTRACT

Subcellular localization of RNA-binding proteins is a key determinant of their ability to control RNA metabolism and cellular stress response. Using an RNAi-based kinome-wide screen, we identified hexokinase 2 (HK2) as a regulator of the cytoplasmic accumulation of hnRNP A1 in response to hypertonic stress and human rhinovirus infection (HRV). We show that inhibition of HK2 expression or pharmacological inhibition of HK2 activity blocks the cytoplasmic accumulation of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), restores expression of B-cell lymphoma-extra large (Bcl-xL), and protects cells against hypertonic stress-induced apoptosis. Reduction of HK2 protein levels by knockdown results in decreased HRV replication, a delay in HRV-induced cell death, and a reduced number of infected cells, all of which can be rescued by forced expression of a cytoplasm-restricted hnRNP A1. Our data elucidate a novel role for HK2 in cellular stress response and viral infection that could be exploited for therapeutic intervention.


Subject(s)
Cytoplasm/metabolism , Enterovirus/physiology , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/genetics , Hexokinase/genetics , Rhinovirus/physiology , Apoptosis/drug effects , Apoptosis/genetics , Cytoplasm/drug effects , Cytoplasm/virology , Enzyme Inhibitors/pharmacology , Gene Expression Regulation , HeLa Cells , Heterogeneous Nuclear Ribonucleoprotein A1 , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/metabolism , Hexokinase/antagonists & inhibitors , Hexokinase/metabolism , Humans , Molecular Imaging , Osmotic Pressure , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Signal Transduction , Virus Replication , bcl-X Protein/genetics , bcl-X Protein/metabolism
5.
Bratisl Lek Listy ; 116(1): 41-6, 2015.
Article in English | MEDLINE | ID: mdl-25666961

ABSTRACT

AIM: In the present study, the role of ethanol extract of root of Taraxacum Syriacum Boiss (TSBE) against hepatotoxicity caused by acetaminophen (APAP) was studied. METHODS: The chemical composition of roots of Taraxacum Syriacum Boiss was analyzed by SPME-GC/MS method. Hepatocellular injuries induced by acetaminophen (APAP) were assessed by liver histology, serum aminotransferase activities, antioxidant enzymes activity and lipid peroxidation in liver tissue. RESULTS: TSBE was observed to exhibit hepatoprotective effect as demonstrated by significant decrease in serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), and alkaline phosphatase (ALP) concentration, and by preventing liver histopathologic changes in rats with APAP hepatotoxicity. Administration of APAP, significantly increased, lactate dehydrogenase (LDH) and catalase (CAT) activity in liver tissue and pretreatment with TSBE returned these parameters to control group, moreover TSBE reduces APAP-induced hepatic Glutathione (GSH) depletion. Carvacrol (6.7 %) was the main polyphenolic compound of plant sample. Our results demonstrated hepatoprotective activity of TSBE in rat in vivo. CONCLUSIONS: We believe that the mechanism by which the extract was able to protect the liver from the oxidative stress generated by APAP is due to its antioxidant activity. These phenolic compounds of the extract act as antioxidants and free radical scavengers and reduce or inhibit the oxidative stress induced by APAP administration (Tab. 3, Fig. 3, Ref. 39).


Subject(s)
Acetaminophen/toxicity , Chemical and Drug Induced Liver Injury/prevention & control , Plant Extracts/chemistry , Plant Extracts/pharmacology , Protective Agents/chemistry , Protective Agents/pharmacology , Taraxacum , Alanine Transaminase/blood , Alkaline Phosphatase/blood , Animals , Antioxidants/pharmacology , Chemical and Drug Induced Liver Injury/metabolism , Chemical and Drug Induced Liver Injury/pathology , Disease Models, Animal , Dose-Response Relationship, Drug , Ethanol , Free Radical Scavengers/pharmacology , Hepatocytes/drug effects , Lipid Peroxidation/drug effects , Male , Oxidative Stress/drug effects , Rats , Rats, Wistar
6.
Acta Physiol Hung ; 101(4): 438-47, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25532955

ABSTRACT

Ghrelin is a gut hormone shown to have protective effects throughout the gastrointestinal tract. This study aims to investigate its protective effect in celiac disease induced in rats. Twenty-four rat pups were divided into 4 groups as follows: control, disease (1.5 mg/g intragastric gliadin), co-treatment (50 ng/g intraperitoneal ghrelin after gliadin gavage) and pretreatment (50 ng/g intraperitoneal ghrelin before gliadin gavage). Animals' weight gain was charted. Histological features assessed include villus length, villus width, crypt depth and number of intraepithelial lymphocytes. Tissue interferon-gamma was quantified by ELISA. ANOVA was used to compare results statistically. Results showed that villi were shortened in the diseased group, but were as long as the control in pretreatment and co-treatment groups. Crypt depth had increased in disease group, but turned to normal in co-treatment group. Number of intraepithelial lymphocytes was significantly higher in disease group than the control, while no difference was observed between co-treatment and control groups. Disease and control animals weighed equally at the end of the experiment, but ghrelin-treated animals had significantly gained more weight than these two. Interferon-gamma measurement revealed no significant difference among groups. We concluded administration of ghrelin led to histological improvement of celiac disease which was more obvious if administered after exposure to gliadin.


Subject(s)
Celiac Disease/prevention & control , Ghrelin/pharmacology , Jejunum/drug effects , Animals , Celiac Disease/chemically induced , Celiac Disease/metabolism , Celiac Disease/pathology , Cytoprotection , Disease Models, Animal , Gliadin , Interferon-gamma/metabolism , Intestinal Mucosa/drug effects , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Jejunum/metabolism , Jejunum/pathology , Rats, Wistar , Time Factors , Weight Gain
7.
Acta Physiol Hung ; 101(3): 341-52, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25183508

ABSTRACT

Endoplasmic reticulum (ER) stress provides abnormalities in insulin action, inflammatory responses, lipoprotein B100 degradation and hepatic lipogenesis. Excess accumulation of triglyceride in hepatocytes may also lead to disorders such as non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Opioid peptides are involved in triglyceride and cholesterol dysregulation, inflammation and cell death. In this study, we evaluated Naltrexone effects on ER stress induced liver injury. To do so, C57/BL6 mice received saline, DMSO and Naltrexone, as control groups. ER stress was induced by tunicamycin (TM) injection. Naltrexone was given before TM administration. Liver blood flow and biochemical serum analysis were measured. Histopathological evaluations, TNF-α measurement and Real-time RT-PCR were also performed. TM challenge provokes steatosis, cellular ballooning and lobular inflammation which significantly reduced in Naltrexone treated animals. ALT, AST and TNF-α increased in the TM group and improved in the Naltrexone plus TM group. Triglyceride and cholesterol levels decreased in TM treated mice with no increase in Naltrexone treated animals. In the Naltrexone plus TM group, gene expression of Bax/Bcl-2 ratio and caspase3 significantly lowered compared with the TM group. In this study, we found that Naltrexone had a notable alleviating role in ER stress induced steatosis and liver injury.


Subject(s)
Chemical and Drug Induced Liver Injury/prevention & control , Endoplasmic Reticulum Stress/drug effects , Endoplasmic Reticulum/drug effects , Fatty Liver/prevention & control , Liver/drug effects , Naltrexone/pharmacology , Narcotic Antagonists/pharmacology , Alanine Transaminase/blood , Animals , Anti-Inflammatory Agents/pharmacology , Aspartate Aminotransferases/blood , Biomarkers/blood , Caspase 3/metabolism , Chemical and Drug Induced Liver Injury/etiology , Chemical and Drug Induced Liver Injury/metabolism , Chemical and Drug Induced Liver Injury/pathology , Chemical and Drug Induced Liver Injury/physiopathology , Cholesterol/blood , Cytoprotection , Disease Models, Animal , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum/pathology , Fatty Liver/chemically induced , Fatty Liver/metabolism , Fatty Liver/pathology , Fatty Liver/physiopathology , Liver/blood supply , Liver/metabolism , Liver/pathology , Liver Circulation/drug effects , Male , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease , Proto-Oncogene Proteins c-bcl-2/metabolism , Triglycerides/blood , Tumor Necrosis Factor-alpha/blood , Tunicamycin , bcl-2-Associated X Protein/metabolism
8.
Neuroscience ; 248: 299-306, 2013 Sep 17.
Article in English | MEDLINE | ID: mdl-23774631

ABSTRACT

Tropisetron, a selective 5-HT3 receptor (5-HT3R) antagonist, has been widely used to counteract chemotherapy-induced emesis. New investigations described the immunomodulatory properties of tropisetron which may not be 5HT3R mediated. In the present study, we assessed the potential effects of tropisetron on an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE). EAE was induced in C57BL/6 mice by myelin oligodendrocyte glycoprotein peptide (MOG35-55) immunization. Animals were treated with tropisetron (5 mg/kg/day); m-chlorophenylbiguanide (mCPBG), a selective 5-HT3R agonist (10 mg/kg/day); tropisetron (5 mg/kg/day) plus mCPBG (10 mg/kg/day), and granisetron (5 mg/kg/day) intraperitoneally on days 3-35 post-immunization. Treatment with tropisetron and granisetron markedly suppressed the clinical symptoms of EAE (p<0.001) and reduced leukocyte infiltration as well as demyelination in the spinal cord (p<0.05). In addition, in vivo tropisetron, granisetron or tropisetron plus mCPBG therapy greatly reduced in vitro MOG35-55-stimulated proliferation of mononuclear cells from spleens, and MOG35-55-induced IL-2, IL-6 and IL-17 production by splenocytes isolated from EAE-induced mice (p<0.05). Concurrent administration of tropisetron and mCPBG did not significantly alter the histological damage in the spinal cord. mCPBG had no effect on the mentioned parameters. Taken together, these findings indicate that tropisetron has considerable immunoregulatory functions in EAE and may be promising for the treatment of MS or other autoimmune and inflammatory diseases of the CNS. Furthermore, beneficial effects of tropisetron in this setting seem to be both receptor dependent and receptor independent in the early phase of the disease.


Subject(s)
Cell Proliferation/drug effects , Demyelinating Diseases/drug therapy , Encephalomyelitis, Autoimmune, Experimental/immunology , Indoles/pharmacology , Leukocytes, Mononuclear/drug effects , Multiple Sclerosis/drug therapy , Animals , Biguanides/administration & dosage , Biguanides/pharmacology , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Therapy, Combination , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Encephalomyelitis, Autoimmune, Experimental/metabolism , Granisetron/administration & dosage , Granisetron/pharmacology , Indoles/administration & dosage , Leukocytes, Mononuclear/cytology , Mice , Mice, Inbred C57BL , Multiple Sclerosis/etiology , Multiple Sclerosis/pathology , Receptors, Serotonin, 5-HT3/drug effects , Serotonin 5-HT3 Receptor Agonists/administration & dosage , Serotonin 5-HT3 Receptor Agonists/pharmacology , Serotonin 5-HT3 Receptor Antagonists/administration & dosage , Serotonin 5-HT3 Receptor Antagonists/pharmacology , Spinal Cord/drug effects , Spinal Cord/pathology , Spleen/cytology , Treatment Outcome , Tropisetron
9.
Eur J Pharm Sci ; 44(4): 514-21, 2011 Nov 20.
Article in English | MEDLINE | ID: mdl-21946260

ABSTRACT

The novel physical hydrogels composed of chitosan or its water soluble derivatives such as carboxymethyl chitosan (CMCh) and sodium carboxymethyl chitosan (NaCMCh) and opened ring polyvinyl pyrrolidone (OP-PVP) were used as a controlled delivery system for triptorelin acetate, a luteinizing-releasing hormone agonist. The in situ gel forming system designed according to physical interactions such as chains entanglements and hydrophilic attractions especially h-bonds of chitosan and/or NaCMCh and OR-PVP. In order to increase in situ gel forming rate the chitosan microspheres prepared through spray drying technique. The chitosan or NaCMCh/OR-PVP blends prepared at different ratios (0.05, 0.10, 0.12, 0.16, 0.20 and 0.24) and suspended in sesame oil as non-aqueous vehicle at different solid content (10-30%). The suitable ratio of polymers with faster in situ gel forming rate was selected for in vivo studies. The gel formation and drug release from the system was evaluated both in vitro and in vivo. In vitro and in vivo results were compared with Diphereline SR 3.75mg, a commercially available controlled delivery system of triptorelin. In vitro release studies showed a sustained release profile for about 192h with first order kinetics. In vivo studies on male rats by determination of serum testosterone were confirmed the acceptable performance of in situ gel forming system compared with Diphereline SR in decreasing the serum testosterone level for 35days, demonstrating the potential of the novel in situ gel forming system for controlled delivery of peptides.


Subject(s)
Drug Delivery Systems/methods , Hydrogels/chemistry , Triptorelin Pamoate/administration & dosage , Animals , Biological Availability , Blood/drug effects , Chitosan/analogs & derivatives , Chitosan/chemical synthesis , Chitosan/chemistry , Delayed-Action Preparations/chemical synthesis , Delayed-Action Preparations/chemistry , Hydrogels/chemical synthesis , Injections, Subcutaneous , Magnetic Resonance Spectroscopy , Male , Materials Testing , Microscopy, Electron, Scanning , Microspheres , Particle Size , Polyvinyls/chemistry , Porosity , Pyrrolidines/chemistry , Rats , Rats, Inbred Strains , Sesame Oil/chemistry , Skin/drug effects , Skin/pathology , Spectrophotometry, Infrared , Testis/drug effects , Testis/pathology , Testosterone/blood , Triptorelin Pamoate/pharmacokinetics , Triptorelin Pamoate/pharmacology
10.
Urol Int ; 86(3): 302-6, 2011.
Article in English | MEDLINE | ID: mdl-21088382

ABSTRACT

INTRODUCTION: Increased levels of nitric oxide (NO) in the spermatic veins of men affected by varicocele have already been reported. But there is no study to discriminate the subtype of catalytic enzyme for synthesis of NO. In this study, aminoguanidine (AG), an inducible NO synthase inhibitor, has been used to investigate its effect on sperm parameters. METHODS: Twenty-four male Wistar rats were divided into four groups. In groups A and B, left experimental varicocele was induced by a 20-gauge needle. Group C (sham) underwent a similar procedure to groups A and B, but the spermatic vein was left intact, and group D served as control group. The animals in group A were killed 10 weeks later and their sperm count, motility, morphology and vitality were evaluated. Group B received 50 mg/kg AG with i.p. injection daily for 10 weeks. RESULTS: Sperm count, motility, morphology and vitality were significantly decreased in group A in comparison to control group (p ≤ 0.05). In group B, sperm parameters improved in comparison to group A (p ≤ 0.01). Group C did not show any significant alterations in sperm parameters compared with control group. CONCLUSION: These findings may support the concept that AG can improve the sperm count, motility, morphology and vitality in infertile rats with varicocele.


Subject(s)
Epididymis/drug effects , Guanidines/pharmacology , Varicocele/drug therapy , Animals , Enzyme Inhibitors/pharmacology , Female , Infertility, Male/pathology , Male , Nitric Oxide Synthase/antagonists & inhibitors , Rats , Rats, Wistar , Reactive Oxygen Species , Sperm Motility , Spermatozoa/pathology , Testis/blood supply
11.
Cancer Invest ; 25(6): 397-404, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17882650

ABSTRACT

FTIR spectroscopy is a common technique for cancer diagnosis. Applied tissue samples are heterogeneous and may be damaged in preparation procedures. Easier sampling, more available samples and also easier process with assured results would be interesting. Whole blood samples include all of these qualifications and our hypothesis was the bio-molecular changes in blood which manifest themselves in different optical signatures, detectable by FTIR spectroscopy. Noncancerous blood samples were differentiated from cancerous ones using ATR-FTIR spectroscopy and LDA classification method. Procedure was 100 percent and 90 percent accurate in prediction of cancerous or noncancerous situation for 33 known and 10 unknown samples, respectively.


Subject(s)
Blood Chemical Analysis/methods , Neoplasms/diagnosis , Spectroscopy, Fourier Transform Infrared/methods , Adult , Aged , Female , Humans , Male , Middle Aged , Neoplasms/blood
12.
Dev Immunol ; 9(3): 151-9, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12892049

ABSTRACT

Although it is well-established that macrophages can occur in distinct activation states, the molecular characteristics of differentially activated macrophages, and particularly those of alternatively activated macrophages (aaMphi), are still poorly unraveled. Recently, we demonstrated that the expression of FIZZ1 and Ym is induced in aaMphi as compared with classically activated macrophages (caMphi), elicited in vitro or developed in vivo during infection with Trypanosoma brucei brucei. In the present study, we analyzed the expression of FIZZ1 and Ym in caMphi and aaMphi elicited during Trypanosoma congolense infection and show that the use of FIZZ1 and Ym for the identification of aaMphi is not limited to T. b. brucei infection and is independent of the organ sources from which macrophages are obtained. We also demonstrate that FIZZ1 can be used to discriminate between different populations of aaMphi. Furthermore, we studied the effects of various stimuli, and combinations thereof, on the expression of FIZZ1 and Ym in macrophages from different mouse strains and demonstrate that regulation of the expression of FIZZ1 and Ym in macrophages is not dependent on the mouse strain. Finally, we show that these genes can be used to monitor the macrophage activation status without the need to obtain pure macrophage populations.


Subject(s)
Lectins/metabolism , Macrophage Activation , Macrophages, Peritoneal/physiology , Proteins/metabolism , Trypanosoma congolense/immunology , Trypanosomiasis, African/immunology , beta-N-Acetylhexosaminidases/metabolism , Animals , Arginine/metabolism , Gene Expression Regulation , Intercellular Signaling Peptides and Proteins , Macrophages, Peritoneal/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Nerve Growth Factor , Trypanosomiasis, African/parasitology
13.
J Mol Biol ; 250(4): 392-406, 1995 Jul 21.
Article in English | MEDLINE | ID: mdl-7616564

ABSTRACT

The carP gene involved in pyrimidine-specific regulation of the upstream P1 promoter of the Escherichia coli carAB operon has been cloned in vivo on a mini-Mu replicon, sequenced and shown to be identical to the xerB (pepA) gene encoding aminopeptidase A, a protein also involved in the Xer-mediated site-specific recombination at ColEI cer. The trans-dominant allele carP6 was cloned as well and shown to bear a single G-->A transition that converts the TGG codon (Trp473) into a TAG amber stop codon. The truncated mutant protein, missing the 31 C-terminal amino acid residues, was shown to be partially active; in the multicopy state the carP6 allele can restore pyrimidine repressibility of the carAB promoter P1. The trans-dominant character of the single copy carP6 allele was found to be suppressed in the presence of multiple copies of the wild-type gene. The carP (pepA) control region was sequenced and transcription shown to be initiated at three promoters, the most upstream one of which was shown to be subject to negative autoregulation. The aminopeptidase activity of CarP (PepA) was found to be dispensable for its role in pyrimidine-mediated repression of carAB transcription. CarP (PepA) was shown to be a sequence-specific DNA-binding protein that does not require, at least not in vitro, any pyrimidine cofactor to bind to the DNA. Mobility-shift and DNase I footprinting experiments have revealed a specific binding of purified CarP (PepA) to two sites in each one of the control regions of the E. coli and Salmonella typhimurium carAB operons and to a single site in the carP (pepA) control region. We propose that integration host factor and CarP/PepA-induced structural modifications in the carAB control region cause conformational changes required to assemble a pyrimidine-specific nucleo-protein regulatory complex.


Subject(s)
Aminopeptidases/genetics , Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)/genetics , DNA-Binding Proteins/genetics , Escherichia coli Proteins , Escherichia coli/genetics , Gene Expression Regulation, Bacterial , Integrases , Amino Acid Sequence , Aminopeptidases/chemistry , Aminopeptidases/isolation & purification , Aminopeptidases/metabolism , Bacterial Proteins/genetics , Bacteriocin Plasmids , Base Sequence , Chromosome Mapping , Cloning, Molecular , DNA Nucleotidyltransferases/genetics , DNA Nucleotidyltransferases/metabolism , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/isolation & purification , DNA-Binding Proteins/metabolism , Escherichia coli/enzymology , Glutamyl Aminopeptidase , Molecular Sequence Data , Mutation , Operon/genetics , Promoter Regions, Genetic/genetics , Pyrimidines/metabolism , Recombinases , Recombination, Genetic/genetics , Repressor Proteins/genetics , Sequence Analysis , Transcription, Genetic/genetics
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