Screening and optimization of extracellular lipases by Acinetobacter species isolated from oil-contaminated soil in South Korea

A total of 53 strains of bacteria were isolated from oil contaminated soil collected in South Korea. The isolated bacteria were screened using spirit blue agar and Rhodamine-B agar media. Two of the isolated strains exhibited a greater clear zone than the others, indicating higher lipase activity. Therefore, these two strains (BK43 and BK44) were selected and identified based on their morphological and physiological characteristics. The 16S rRNA gene sequencing was also implemented. Phylogenetic analyses based on the results of 16S rRNA gene sequencing revealed that BK43 and BK44 were close in identity to Acinetobacter junii. The optimum pH and temperature for lipase production by BK43 were found to be 6.0 at 30°C, after 24 h of incubation, while BK44 were found to be 6.0 at 25°C, after 12 h of incubation. In addition, increased enzymatic production was obtained when the organisms were cultured in medium supplemented with 1% sucrose as the carbon source. Among the different lipase inducers tested, both strains utilized Tween 80 and produced a great level of extracellular lipase. Overall, the results of the present study demonstrate that the genus Acinetobacter is good for extracellular lipase production under acidic conditions.Key words: Acinetobacter, lipase, optimization, screening

Rationale and design of BISTRO: a randomized controlled trial to determine whether bioimpedance spectroscopy guided fluid management maintains residual kidney function in incident haemodialysis patients

Background: Preserved residual kidney function (RKF) and normal fluid status are associated with better patient outcomes in incident haemodialysis patients. The objective of this trial is to determine whether using bioimpedance technology in prescribing the optimal post-dialysis weight can reduce the rate of decline of RKF and potentially improve patient outcomes. Methods/Design: 516 patients commencing haemodialysis, aged >18 with RKF of > 3 ml/min/1.73 m2 or a urine volume >500 ml per day or per the shorter inter-dialytic period will be consented and enrolled into a pragmatic, open label, randomized controlled trial. The intervention is incorporation of bioimpedance spectroscopy (BI) determination of normally hydrated weight to set a post-dialysis target weight that limits volume depletion, compared to current standard practice. Clinicians and participants will be blinded to BI measures in the control group and a standardized record capturing management of fluid status will be used in all participants. Primary outcome is preservation of residual kidney function assessed as time to anuria (≤100 ml/day or ≤200 ml urine volume in the short inter-dialytic period). A sample size of 516 was based upon a cumulative incidence of 30% anuria in the control group and 20% in the treatment group and 11% competing risks (death, transplantation) over 10 months, with up to 2 years follow-up. Secondary outcomes include rate of decline in small solute clearance, significant adverse events, hospitalization, loss of vascular access, cardiovascular events and interventions, dialysis efficacy and safety, dialysis-related symptoms and quality of life. Economic evaluation will be carried out to determine the cost-effectiveness of the intervention. Analyses will be adjusted for patient characteristics and dialysis unit practice patterns relevant to fluid management. Discussion: This trial will establish the added value of undertaking BI measures to support clinical management of fluid status and establish the relationship between fluid status and preservation of residual kidney function in incident haemodialysis patients. Trial registration: ISCCTN Number: 11342007, completed 26/04/2016; NIHR Portfolio number: CPMS31766; Sponsor: Keele University Keywords: Fluid status, Body composition, Residual kidney function, Haemodialysis, Bioimpedance, Fluid management, Health economic

Mechanism of Action of Cyclophilin A Explored by Metadynamics Simulations

Trans/cis prolyl isomerisation is involved in several biological processes, including the development of numerous diseases. In the HIV-1 capsid protein (CA), such a process takes place in the uncoating and recruitment of the virion and is catalyzed by cyclophilin A (CypA). Here, we use metadynamics simulations to investigate the isomerization of CA's model substrate HAGPIA in water and in its target protein CypA. Our results allow us to propose a novel mechanistic hypothesis, which is finally consistent with all of the available molecular biology data

CXCR2 Signaling Protects Oligodendrocytes and Restricts Demyelination in a Mouse Model of Viral-Induced Demyelination

BACKGROUND: The functional role of ELR-positive CXC chemokines during viral-induced demyelination was assessed. Inoculation of the neuroattenuated JHM strain of mouse hepatitis virus (JHMV) into the CNS of susceptible mice results in an acute encephalomyelitis that evolves into a chronic demyelinating disease, modeling white matter pathology observed in the human demyelinating disease Multiple Sclerosis. METHODOLOGY/PRINCIPAL FINDINGS: JHMV infection induced the rapid and sustained expression of transcripts specific for the ELR+ chemokine ligands CXCL1 and CXCL2, as well as their binding receptor CXCR2, which was enriched within the spinal cord during chronic infection. Inhibiting CXCR2 signaling with neutralizing antiserum significantly (p<0.03) delayed clinical recovery. Moreover, CXCR2 neutralization was associated with an increase in the severity of demyelination that was independent of viral recrudescence or modulation of neuroinflammation. Rather, blocking CXCR2 was associated with increased numbers of apoptotic cells primarily within white matter tracts, suggesting that oligodendrocytes were affected. JHMV infection of enriched oligodendrocyte progenitor cell (OPC) cultures revealed that apoptosis was associated with elevated expression of cleaved caspase 3 and muted Bcl-2 expression. Inclusion of CXCL1 within JHMV infected cultures restricted caspase 3 cleavage and increased Bcl-2 expression that was associated with a significant (p<0.001) decrease in apoptosis. CXCR2 deficient oligodendrocytes were refractory to CXCL1 mediated protection from JHMV-induced apoptosis, readily activating caspase 3 and down regulating Bcl-2. CONCLUSION/SIGNIFICANCE: These findings highlight a previously unappreciated role for CXCR2 signaling in protecting oligodendrocyte lineage cells from apoptosis during inflammatory demyelination initiated by viral infection of the CNS

Genetic contributions to self-reported tiredness

Self-reported tiredness and low energy, often called fatigue, are associated with poorer physical and mental health. Twin studies have indicated that this has a heritability between 6 and 50%. In the UK Biobank sample (N=108 976), we carried out a genome-wide association study (GWAS) of responses to the question, ‘Over the last two weeks, how often have you felt tired or had little energy?’ Univariate GCTA-GREML found that the proportion of variance explained by all common single-nucleotide polymorphisms for this tiredness question was 8.4% (s.e.=0.6%). GWAS identified one genome-wide significant hit (Affymetrix id 1:64178756_C_T; P=1.36 × 10−11). Linkage disequilibrium score regression and polygenic profile score analyses were used to test for shared genetic aetiology between tiredness and up to 29 physical and mental health traits from GWAS consortia. Significant genetic correlations were identified between tiredness and body mass index (BMI), C-reactive protein, high-density lipoprotein (HDL) cholesterol, forced expiratory volume, grip strength, HbA1c, longevity, obesity, self-rated health, smoking status, triglycerides, type 2 diabetes, waist–hip ratio, attention deficit hyperactivity disorder, bipolar disorder, major depressive disorder, neuroticism, schizophrenia and verbal-numerical reasoning (absolute rg effect sizes between 0.02 and 0.78). Significant associations were identified between tiredness phenotypic scores and polygenic profile scores for BMI, HDL cholesterol, low-density lipoprotein cholesterol, coronary artery disease, C-reactive protein, HbA1c, height, obesity, smoking status, triglycerides, type 2 diabetes, waist–hip ratio, childhood cognitive ability, neuroticism, bipolar disorder, major depressive disorder and schizophrenia (standardised β’s had absolute values<0.03). These results suggest that tiredness is a partly heritable, heterogeneous and complex phenomenon that is phenotypically and genetically associated with affective, cognitive, personality and physiological processes

Effect of membrane structure on the performance of field-effect transistor potassium-sensitive sensor

An EET-type K+ -sensitive sensor with a membrane composed of a hydrophobic inner layer and a hydrophilic outer layer has been fabricated by a photolithographic process. The base chip for the sensor is a pH-ISFET with a thin Si3N4 layer. Negative photoresist (OMR-83) is used as the inner layer and poly(vinyl pyrrolidinone-co-vinyl acetate) solution in tetrahydrofuran containing valinomycin and 2,6-bis-(p-azidobenzylidene) cyclohexanone photosensitizer is used as the outer sensing membrane material. The K-ISFET sensor with double-layered membrane shows a high sensitivity (56 mV/decade) toward K+ ion, rapid response (1-2s) and low interference (less than 3mV/decade) from the competing H+ ionclose121

New chaotic patterns in pulsed discharges

We observed new chaotic patterns in discharge spikes of a pulsed plasma system having parallel electrodes and dielectric barriers. The chaotic behavior was modeled by computer-intensive simulations and a separate semi-analytic map, showing that the periodic patterns transit to chaos without standard cascades such as period doubling, quasiperiodicity, or intermittence.close1