333 research outputs found

    High energy-charged cell factory for heterologous protein synthesis

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    Overexpression of gluconeogenic phosphoenolpyruvate carboxykinase (PCK) under glycolytic conditions enables Escherichia coli to maintain a greater intracellular ATP concentration and, consequently, to up-regulate genes for amino acid and nucleotide biosynthesis. To investigate the effect of a high intracellular ATP concentration on heterologous protein synthesis, we studied the expression of a foreign gene product, enhanced green fluorescence protein (eGFP), under control of the T7 promoter in E. coli BL21(DE3) strain overexpressing PCK. This strain was able to maintain twice as much intracellular ATP and to express two times more foreign protein than the control strain. These results indicate that a high energy-charged cell can be beneficial as a protein-synthesizing cell factory. The potential uses of such a cell factory are discussed

    Proteome-Level Responses of Escherichia coli to Long-Chain Fatty Acids and Use of Fatty Acid Inducible Promoter in Protein Production

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    In Escherichia coli, a long-chain acyl-CoA is a regulatory signal that modulates gene expression through its binding to a transcription factor FadR. In this study, comparative proteomic analysis of E. coli in the presence of glucose and oleic acid was performed to understand cell physiology in response to oleic acid. Among total of 52 proteins showing altered expression levels with oleic acid presence, 9 proteins including AldA, Cdd, FadA, FadB, FadL, MalE, RbsB, Udp, and YccU were newly synthesized. Among the genes that were induced by oleic acid, the promoter of the aldA gene was used for the production of a green fluorescent protein (GFP). Analysis of fluorescence intensities and confocal microscopic images revealed that soluble GFP was highly expressed under the control of the aldA promoter. These results suggest that proteomics is playing an important role not only in biological research but also in various biotechnological applications

    Association of Bone Mineral Density With Hearing Impairment in Postmenopausal Women in Korea

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    Objectives Previous studies examining the association between osteoporosis (OP) and hearing loss (HL) have shown conflicting results. The objective of the present study was to examine the association between hearing impairment and OP in postmenopausal women, using appropriate statistical analyses. Methods Total 1,009 participants were included in the current study. The propensity score matched (PSM) cohort was defined as the cohort including participants diagnosed with OP and participants without OP. Three statistical models were developed where model 1 was unadjusted, model 2 included age, and model 3 included age, body mass index, alcohol intake, smoking habit, diabetes mellitus, hypertension, high density lipoprotein cholesterol, triglyceride level, vitamin D, and alkaline phosphatase. Results There were 776 and 233 participants in the groups diagnosed without and with OP, respectively. For propensity score matching, 233 pairs were selected from the 776 participants without OP. In the total cohort, using statistical models 2 and 3, no significant difference in the four hearing thresholds was identified between the 2 groups. Logistic regression indicated that, in model 3, participants with OP had a 1.128 (P=0.323) increased risk HL. A significant HL risk was not observed in participants with OP. Using statistical model 3, there were no significant associations among lumbar spine or femoral neck T-scores and changes in the hearing thresholds. In the PSM cohort, statistical models also showed similar results. Conclusion The current study did not demonstrate and association between bone mineral density and hearing impairment in the study population of postmenopausal Korean women

    Transcriptome and proteome analyses of adaptive responses to methyl methanesulfonate in Escherichia coli K-12 and ada mutant strains

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    <p>Abstract</p> <p>Background</p> <p>The Ada-dependent adaptive response system in <it>Escherichia coli </it>is important for increasing resistance to alkylation damage. However, the global transcriptional and translational changes during this response have not been reported. Here we present time-dependent global gene and protein expression profiles following treatment with methyl methanesulfonate (MMS) in <it>E. coli </it>W3110 and its <it>ada </it>mutant strains.</p> <p>Results</p> <p>Transcriptome profiling showed that 1138 and 2177 genes were differentially expressed in response to MMS treatment in the wild-type and mutant strains, respectively. A total of 81 protein spots representing 76 nonredundant proteins differentially expressed were identified using 2-DE and LC-MS/MS. In the wild-type strain, many genes were differentially expressed upon long-exposure to MMS, due to both adaptive responses and stationary phase responses. In the <it>ada </it>mutant strain, the genes involved in DNA replication, recombination, modification and repair were up-regulated 0.5 h after MMS treatment, indicating its connection to the SOS and other DNA repair systems. Interestingly, expression of the genes involved in flagellar biosynthesis, chemotaxis, and two-component regulatory systems related to drug or antibiotic resistance, was found to be controlled by Ada.</p> <p>Conclusion</p> <p>These results show in detail the regulatory components and pathways controlling adaptive response and how the related genes including the Ada regulon are expressed with this response.</p

    Association Between Hearing Impairment and Albuminuria With or Without Diabetes Mellitus

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    Objectives Few studies have evaluated the accurate association between hearing loss (HL) and albuminuria in patients with or without diabetes mellitus (DM). The aim of our study was to identify the clinical effects of albuminuria on HL with or without DM. Methods This study included 9,762 patients from the Korean National Health and Nutrition Examination Survey between 2011 and 2013. Participants were divided into 4 groups based on DM and urine albumin/creatinine ratio levels: group 1 included participants with neither DM nor albuminuria, group 2 included participants without DM and with albuminuria, group 3 included patients with DM and without albuminuria, and group 4 included patients with both DM and albuminuria. The low- or mid-frequency and high-frequency, and average hearing threshold values were obtained. Results There were 7,508, 545, 1,325, and 384 participants in groups 1, 2, 3, and 4, respectively. Univariate and multivariate analyses showed that the 3 hearing thresholds in group 1 were the lowest and those in group 4 were the highest among the 4 groups. No significant differences were observed in those thresholds between groups 2 and 3. Group 4 was associated with HL compared with the other groups, but moderate to severe HL was not associated with DM or albuminuria. Conclusion The presence of albuminuria was associated with a modest effect on hearing thresholds regardless of presence of DM

    Reciprocal Relationship Between Depression and Internet Gaming Disorder in Children: A 12-month Follow-Up of the iCURE Study Using Cross-Lagged Path Analysis

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    Objectives: Previous studies have reported an association between Internet gaming disorder (IGD) and depression, but the directionality of the relationship remains unclear. Therefore, we examined the reciprocal relationship between level of depressive symptoms and IGD among children in a longitudinal study. Methods: Research panels for this study consisted of 366 elementary-school students in the iCURE study. All participants were current Internet users, so they could be considered an at-risk population for IGD. Self-reported severity of IGD features and level of depression were assessed by the Internet Game Use-Elicited Symptom Screen and Children’s Depression Inventory, respectively. Follow-up assessment was completed after 12 months. We fitted cross-lagged structural equation models to investigate the association between the two variables at two time points contemporaneously. Results: The cross-lagged analysis revealed that level of depression at baseline significantly predicted severity of IGD features at the 12-month follow-up (β = 0.15, p = .003). Severity of IGD features at baseline also significantly predicted level of depression at the 12-month follow-up (β = 0.11, p = .018), controlling for possible confounding factors. Conclusions: The cross-lagged path analysis indicates a reciprocal relationship between severity of IGD features and level of depressive symptoms. Understanding the reciprocal relationship between depressive symptoms and severity of IGD features can assist in interventions to prevent both conditions. These findings provide theoretical support for prevention and remediation plans for IGD and depressive symptoms among children

    Hysteroscopic Resection of the Vaginal Septum in Uterus Didelphys with Obstructed Hemivagina: A Case Report

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    Uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis is a rare congenital anomaly. Excision of the obstructed vaginal septum is the treatment of choice for symptom relief and the preservation of reproductive capability. A 14-yr-old girl complained of persistent vaginal spotting following each menstruation. Pelvic magnetic resonance imaging revealed a uterus didelphys with left hematocolpos and ipsilateral renal agenesis. Instead of conventional transvaginal excision of the vaginal septum, we used hysteroscopic excision under transabdominal ultrasonographic guidance to preserve the integrity of the hymen. The postoperative course was uneventful, and clinical symptoms were completely resolved after this intervention. Resectoscopic excision of the vaginal septum was found to be easy, safe, effective, and appropriate for young women as it preserved hymen integrity. We believe that this is the first Korean report on the use of a hysteroscopy for vaginal septum resection in a patient with uterus didelphys with obstructed hemivagina

    A Family of H723R Mutation for SLC26A4 Associated with Enlarged Vestibular Aqueduct Syndrome

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    Recessive mutations of the SLC26A4 (PDS) gene on chromosome 7q31 can cause sensorineural deafness with goiter (Pendred syndrome, OMIM 274600) or NSRD with goiter (at the DFNB4 locus, OMIM 600791). H723R (2168A>G) is the most commonly reported SLC26A4 mutations in Korean and Japanese and known as founder mutation. We recently experienced one patient with enlarged vestibular aqueduct syndrome. The genetic study showed H723R homozygous in the proband and H723R heterozygous mutation in his family members. The identification of a disease-causing mutation can be used to establish a genotypic diagnosis and provide important information to both families and their physicians
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