Genetic polymorphisms of glutathione S-transferase <Emphasis Type="Italic">Z1</Emphasis> in an Iranian population

Genetic polymorphisms in gene encoding glutathione S-transferase Z1 (GSTZ1, a member of class zeta) have been defined. Previous studies have revealed that there was significant difference between populations for allelic frequency of several members of GSTs. In order to get more insight into the genetic structure of Iranian population the present study was done on Iranian Persian population who living in Shiraz (Fars province). The total study subjects consisted of 689 unrelated healthy individuals. Genetic polymorphisms for G-1002A, Glu32Lys and Gly42Arg of the GSTZ1 were detected by RFLP-PCR-based method. Allelic frequency of 32Lys, 42Arg, and −1002G was 0.2337, 0.0298 and 0.2184, respectively. The study population was at Hardy–Weinberg equilibrium for the polymorphisms of GSTZ1. Based on the complete dataset, these polymorphisms show significant linkage disequilibrium. Iranian gene pool showed intermediate frequency for alleles and haplotypes of GSTZ1 polymorphisms in comparison with European and Asian countries, which confirmed our previous reports for other genetic polymorphisms.     

Nasal carriage of methicillin resistant Staphylococcus aureus and their antibiotic susceptibility patterns in children attending day-care centers

Nasal colonization with community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is being increasingly reported, especially in places where people are in close contact and in reduced hygiene, such as day-care centers. In this study we investigated the frequency of MRSA colonization and their antibiotic susceptibility patterns in 1-6 years old children of day-care centers in Hamadan, West of Iran.Five hundred nasal swabs were collected from children of 27 day-care centers that had no risk factors for colonization by S. aureus. The specimens were cultured for isolation of S. aureus by standard methods. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. For evaluation of the frequency of erythromycin induced clindamycin resistance, disk approximation test (D-test) was applied.Totally, 148 (29.6%) children were colonized by S. aureus. Out of 260 male, 94 (36.2%) and of 240 female, 54 (22.5%) cases were nasal carriers of S. aureus (P value = 0.001). Six (4.1%) of the 148 S. aureus isolated from children were MRSA strains. None of MRSA and methicillin susceptible S. aureus (MSSA) was resistant to vancomycin and clindamycin. Three of the 6 strains of MRSA and 7 (4.9%) of the 142 MSSA strains were resistant to erythromycin, and D-test was positive in all of them.We conclude that the rate of colonization by S. aureus is high in children attending day-care centers but colonization with MRSA is not common in our areas. Clindamycin or trimethoprim-sulfamethoxazol could be used in mild to moderataly severe diseases caused by CA-MRSA. However, if the CA-MRSA isolates are erythromycin resistant, D-test should be carried out for detection of inducible clindamycin resistance.     

Analysis of DNA fragmentation in mouse embryos exposed to an extremely low-frequency electromagnetic field

Effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on DNA damage in biological systems are still a matter of dispute. The aim of the present study was to investigate the possible effect of electromagnetic field exposure on DNA fragmentation in cells (blastomers) of mouse blastocysts. Eighty female NMRI mice were randomly divided into 2 groups of 40 animals each. The control group was left unexposed whereas the animals in the EMF-group were exposed to a 50-Hz EMF at 0.5?mT 4?h per day, 6 days a week for a duration of 2 weeks. After the 8(th) day of exposure, the female mice in both groups were superovulated (with injections of pregnant mare serum gonadotropin and human chorionic gonadotropin) and then mated overnight. At approximately 4 days after mating (102?h after the human chorionic gonadotropin treatment), blastocysts were obtained by flushing the uterus horns. The mean numbers of pregnant mice, blastocysts after flushing, blastomers within the blastocysts, and the DNA fragmentation index following staining in both groups were compared using statistical methods (SPSS, the Chi-square test, the Student's t-test and the Mann-Whitney U-test, P?相似文献   

High-level production of extracellular lipase by Yarrowia lipolytica mutants from methyl oleate

The yeast Yarrowia lipolytica degrades efficiently low-cost hydrophobic substrates for the production of various added-value products such as lipases. To obtain yeast strains producing high levels of extracellular lipase, Y. lipolytica DSM3286 was subjected to mutation using ethyl methanesulfonate (EMS) and ultraviolet (UV) light. Twenty mutants were selected out of 1600 mutants of Y. lipolytica treated with EMS and UV based on lipase production ability on selective medium. A new industrial medium containing methyl oleate was optimized for lipase production. In the 20 L bioreactor containing new industrial medium, one UV mutant (U6) produced 356 U/mL of lipase after 24h, which is about 10.5-fold higher than that produced by the wild type strain. The properties of the mutant lipase were the same as those of the wild type: molecular weight 38 kDa, optimum temperature 37°C and optimum pH 7. Furthermore, the nucleotide sequences of extracellular lipase gene (LIP2) in wild type and mutant strains were determined. Only two silent substitutions at 362 and 385 positions were observed in the ORF region of LIP2. Two single substitutions and two duplications of the T nucleotide were also detected in the promoter region. LIP2 sequence comparison of the Y. lipolytica DSM3286 and U6 strains shows good targets to effective DNA recombinant for extracellular lipase of Y. lipolytica.     

Neuronal spike train analysis in likelihood space

Background

Conventional methods for spike train analysis are predominantly based on the rate function. Additionally, many experiments have utilized a temporal coding mechanism. Several techniques have been used for analyzing these two sources of information separately, but using both sources in a single framework remains a challenging problem. Here, an innovative technique is proposed for spike train analysis that considers both rate and temporal information.

Methodology/Principal Findings

Point process modeling approach is used to estimate the stimulus conditional distribution, based on observation of repeated trials. The extended Kalman filter is applied for estimation of the parameters in a parametric model. The marked point process strategy is used in order to extend this model from a single neuron to an entire neuronal population. Each spike train is transformed into a binary vector and then projected from the observation space onto the likelihood space. This projection generates a newly structured space that integrates temporal and rate information, thus improving performance of distribution-based classifiers. In this space, the stimulus-specific information is used as a distance metric between two stimuli. To illustrate the advantages of the proposed technique, spiking activity of inferior temporal cortex neurons in the macaque monkey are analyzed in both the observation and likelihood spaces. Based on goodness-of-fit, performance of the estimation method is demonstrated and the results are subsequently compared with the firing rate-based framework.

Conclusions/Significance

From both rate and temporal information integration and improvement in the neural discrimination of stimuli, it may be concluded that the likelihood space generates a more accurate representation of stimulus space. Further, an understanding of the neuronal mechanism devoted to visual object categorization may be addressed in this framework as well.     

Coleopteran-specific and putative novel cry genes in Iranian native Bacillus thuringiensis collection

The characterization of the strains containing Coleopteran-specific and also putative novel cry genes in Iranian native Bacillus thuringiensis collection is presented. Characterization was based on PCR analysis using 31 general and specific primers for cry1B, cry1I, cry3A, cry3B, cry3C, cry7A, cry8A, cry8B, cry8C, cry14, cry18, cry26, cry28, cry34 and cry35 genes, protein band patterns as well as their insecticidal activity on Xanthogaleruca luteola Mull. larvae. Forty six isolates (65.7%) contained minimum one Coleopteran-active cry gene. Based on universal primers, strains containing cry18 and cry26 genes were the most abundant and represent 27.1% and 24% of the isolates, respectively, whereas cry14, cry3, cry28, cry34, cry35, cry7, cry8 genes were less abundant, found in 14.2, 12.5, 10, 7, 7 and 5.6% of the strains, respectively. Based on specific primers, isolates containing cry1I were the most abundant (48.5%). Two strains containing Coleopteran-active cry genes showed higher activity against X. luteola larvae than B. thuringiensis subsp. morrisoni pathovar tenebrionis. Thirty isolates, when assayed for cry1C, cry5, cry6, cry8b, cry9, cry10, cry11, cry18, cry24 and cry35 genes, showed unexpected size bands. Cloning and sequencing of the amplicons allowed both the identification of known cry genes and the detection of putative novel cry1C sequences.     

Cloning,expression and immunogenicity of ferric enterobactin binding protein Fep B from <Emphasis Type="Italic">Escherichia coli</Emphasis> O157:H7

The gene coding for ferric enterobactin binding protein from E. coli O157:H7 was amplifi ed. This gene was cloned and expressed as C-terminal His (6)-tagged protein. The SDS-PAGE analysis of the total protein revealed only two distinct bands, with molecular masses of 31kDa and 34kDa. The Ni-NTA chromatography purifi ed FepB and the osmotically shocked periplasmic fraction of IPTG induced cells showed only a single band of 31 kDa. Polyclonal mouse antibody was raised against the recombinant protein during 4 weeks after immunization. Western blot analysis of the recombinant FepB with mouse antiserum revealeda single band of 31 kDa. Identification and purification of FepB helped reveal its appropriate molecular mass. Polyclonal antibody raised against the recombinant protein reacted with bacterial FepB. The recombinant protein FepB could have a protective effect against E. coli O157:H7 and might be useful as an effective vaccine.     

Differentiation of human ES cell-derived neural progenitors to neuronal cells with regional specific identity by co-culturing of notochord and somite

Limitations to the in vivo study of human nervous system development make it necessary to design an in vitro model to evaluate the in vivo effects of surrounding tissues on neurogenesis and regional identity of the human neural plate. Rostral neural progenitors (NPs) were initially generated from adherent human embryonic stem cells (hESCs) in a defined condition and characterized. Then, to find the role of somites (S) and notochords (N) in rostro-caudal (RC) and dorso-ventral (DV) patterning of neuronal cells, NPs were co-cultured with microencapsulated chicken S or N in alginate beads. In this study, N induced more neurogenesis as evaluated by expression of TUJ1 and MAP2-positive cells. Additionally, N induced spinal cord ventral brachiothoracic identity as well as NPs proliferation. We observed a synergic effect on motoneuron induction when S and N were used together. Moreover, S induced hindbrain identity in differentiated neuronal cells from NPs. These results indicate that highly enriched NPs can be generated in an adherent and defined system from hESCs. Moreover, S and N tissues highly influenced neuronal differentiation in point of proliferation, neurogenesis, and RC and DV regional identity. These results indicate a very simple and efficient protocol to mimic in vivo events of human neural development in vitro which is important in the context of developmental neuroscience and cellular replacement therapies.     

Relationship among plasma adipokines, insulin and androgens level as well as biochemical glycemic and lipidemic markers with incidence of PCOS in women with normal BMI

Polycystic ovary syndrome (PCOS) is an endocrine disorder in women. Omentin-1 and vaspin are secretary adipokines that are produced by the visceral adipose tissue. These levels change in obese women with PCOS. The aim of this study is to investigate whether omentin and vaspin levels change in nonobese PCOS subjects. This study is a cross-sectional case control study in which 39 women with PCOS were picked out for this study. The inclusion criteria were based on the Rotterdam 2003 diagnostic criteria. The control group consisted of 39 women with normal pelvic sonographic reports having regular menstruation and showing no signs of infertility. The fasting plasma glucose (FPG), triglyceride (TG), Chol, and high-density lipoprotein cholesterol (HDL-C), insulin, testosterone, omentin and vaspin were measured by the enzymatic methods. The differences within these groups were calculated by the un-paired t-test and the Mann-Whitney test. The results from this study show a significant increase in the amount of insulin, testosterone, homeostasis model assessments for insulin resistance, TG and lower HDL in the patient group. No significant differences were seen in omentin, vaspin, FPG, Cho, low-density lipoprotein, very low-density lipoprotein cholesterol, blood urea nitrogen, Cr and homeostasis model assessments for B cell function levels between groups. Results show that PCOS is not a determinant of decreased omentin and vaspin plasma levels and those high androgen level and insulin resistances are warning signs of PCOS.     

An in silico chimeric multi subunit vaccine targeting virulence factors of enterotoxigenic Escherichia coli (ETEC) with its bacterial inbuilt adjuvant

Enteric infections resulting in diarrheal diseases remain as major global health problems. Among bacteria, enterotoxigenic Escherichia coli (ETEC) causes the largest number of diarrheal cases. There is a great interest in developing an effective ETEC vaccine. An ETEC vaccine could focus on virulence factors present in ETEC pathogens and nontoxic Heat-labile B subunit (LTB). Chimeric proteins carrying epitopes, or adjuvant sequences increase the possibility of eliciting a broad cellular or humoral immune response. In-silico tools are highly suited to study, design and evaluate vaccine strategies. Colonization factors are among the virulence factor studied in the present work employing bioinformatic tools. A synthetic chimeric gene, encoding CfaB, CstH, CotA, and LTB was designed. Modeling was done to predict the 3D structure of protein. This model was validated using Ramachandran plot statistics. The predicted B-cell epitopes were mapped on the surface of the model. Validation result showed that 97.2% residues lie in favored or additional allowed region of Ramachandran plot. VaxiJen analysis of the protein showed high antigenicity. Linear and conformational B-cell epitopes were identified. The identified T-cell epitopes are apt to bind MHC molecules. The epitopes in the chimeric protein are likely to induce both the B-cell and T-cell mediated immune responses.