In vitro, acidic, non-proteinaceous antifungal activities of lactic acid bacteria isolated from salad vegetables against human pathogenic Candida albicans

Background: The antagonistic abilities of lactic acid bacteria (LAB) against clinical isolates of Candida albicans are not quite widely reported and such are even scarce in Nigeria. This study therefore investigated inhibitory potentials of LAB isolated from locally grown cabbage, cucumber and lettuce against four (4) clinical isolates of C. albicans.Methods: The cell free supernatants (CFS) generated from LAB culture filtrate was evaluated for anti-candida activity using agar well diffusion method, and the CFS-LAB pH was measured and neutralized using standard methods. The proteinaceous inhibitory metabolites were assayed for using sodium dodecylsulphate polyacrilamide gel electrophoresis (SDS-PAGE) technique. The LAB strains used were previously isolated and identified by 16S rRNA partial sequencing and their data submitted to GenBank for accessioning.Results: The CFS of six (6) LAB strains showed varying degrees of anti-candida activity. Pediococcus pentosaceus BTA 51 from cucumber showed the widest inhibition zone of 14 mm while at neutral pH, it was 12 mm diameter. Weissella confusa BTA 20, BTA 40 isolated from cabbage and lettuce produced 10 mm and 12 mm zones of inhibition at acidic and neutral pH respectively. Lactobacillus plantarum BTA 07 from lettuce showed inhibition zone of 12 mm while L. fermentum BTA 47 and BTA 62 from cucumber showed zones of 14 mm each in acidic pH only. The SDS-PAGE did not detect any proteinaceous substances.Conclusion: In conclusion, LAB isolated from cabbage, cucumber and lettuce produced organic acids, non proteinaceous metabolites at neutral pH, exhibiting invitro inhibitory abilities against clinical isolates of C. albicans.Keywords: In vitro, Lactic acid bacteria, 16S rRNA, antifungal, SDS-PAGE, salad vegetable

Non detection of mecA gene in methicillin resistant Staphylococcus aureus isolates from pigs

Background: Methicillin resistant Staphylococcus aureus (MRSA) have become a global health problem causing infections in both humans and livestock, ranging from skin and soft tissue to life threatening blood stream infections. The mecA gene is known to confer resistance to MRSA isolates. This study investigated the carriage of mecA gene by MRSA isolates from pigs.Methods: One hundred non duplicate staphylococcal isolates recovered from blood samples of pigs in Bariga district of Lagos State at the Molecular Biology and Biotechnology unit of the Nigerian Institute of Medical Research were used in the study. S. aureus was identified by cultural characteristics, and positive catalase, coagulase and deoxyribonuclease tests. Phenotypic methicillin resistance was determined by the modified Kirby Bauer disk diffusion method and mecA gene was detected by conventional polymerase chain reaction (PCR) assay.Results: Twenty-five S. aureus were identified, of which 11 (44%) were MRSA by phenotypic method. All the isolates were mecA negative on PCR.Conclusion: The MRSA phenotype observed in the pig isolates in this study appears not to be the classical mecA mediated resistance. There may be alternative mechanisms of resistance in MRSA isolates in pigs.Keywords: MRSA, phenotypic, mecA gene, PCR, pig

Effects of time resolution on finances and self-consumption when modeling domestic PV-battery systems

When modeling a renewable energy system, the timestep to use is an important consideration. Timestep, or time resolution, can have an impact on results, influencing the sizing of the system and whether or not to invest at all. In this work, real measured data for an entire year at 15-s resolution from a rooftop PV array and 8 household loads in the UK are used. The PV and load time series are averaged to lower resolution: 1-min, 5-min, 30-min and 1-h, and the results from using them as input to a 25-year simulation of PV-only and PV-battery systems are compared to the 15-s resolution results. Load resolution is confirmed to be more important than PV resolution for improving accuracy of self-sufficiency and cost metrics; the presence of a battery is confirmed to reduce the errors of using low resolution compared to PV-only. However, these findings only apply to the commonly tested Greedy algorithm but not the newly developed Emissions Arbitrage algorithm. A wider range of metrics are calculated here than in previous work, finding consistency in that low resolution overstates the benefits of PV-battery, but variation in percentage difference across the metrics used. Further aspects not studied before include: the diminishing returns in computation speed when time resolution is lowered, and the effect of time resolution on the tipping point when certain configurations become more attractive propositions than others. Time resolution of input data and modeling are issues not only for researchers in academia and industry, but from a consumer protection perspective too

Characterization of biofilm formation in clinical urinary isolates of Staphylococcus aureus from five hospitals in Lagos State, Nigeria

Background: Biofilm formation by pathogens is of great clinical importance as it mediates persistence and resistance to antibiotics, hence posing difficulty in treatment and management of diseases. The aim of this study was to evaluate the biofilm forming potential of Staphylococcus aureus isolated from urine samples of females with urinary tract infection and to detect the presence of clumping factor (clfA) and intracellular adhesion (icaA) encoding genes.Methodology: A total of 50 S. aureus were obtained from urine samples of women in five hospitals in Lagos State, Nigeria. Isolates were confirmed by standard biochemical and novobiocin susceptibility tests. The isolates were screened for biofilm formation using three methods; Congo-red agar (CRA), tube, and tissue culture plate (TCP) methods. Detection of clfA and icaA genes was done by PCR.Results: The Congo red agar method showed that 39 (78%) of the isolates were biofilm producers while 11 (22%) were non-biofilm producers. However, the tube method indicated that 12 (24%) were strong biofilm producers, 26 (52%) were moderate biofilm producers, and 12 (24%) were non-biofilm producers. The standard TCP assay showed that strong biofilm producers (OD > 0.240) were 13 (26%), moderate biofilm producers were 22 (44%), and weak or non-biofilm producers (OD < 0.120) were 15 (30%). The tube method showed a good correlation with the TCP method for strong biofilm production. Ten (20%) isolates possessed clfA gene and 31 (62%)possessed icaA gene.Conclusion: The ability of S. aureus to form biofilm is a key risk factor that can increase morbidity and mortality from infections they cause. Hence, rapid and sensitive phenotypic methods can be used in screening for biofilm formation thereby providing data that can guide therapy and control of the pathogen. Keywords: Staphylococcus aureus, Biofilm, Clumping factor, Intracellular adhesio

Pair Production and Vacuum Polarization of Arbitrary Spin Particles with EDM and AMM

The exact solutions of the wave equation for arbitrary spin particles with electric dipole and magnetic moments in the constant and uniform electromagnetic field were found. The differential probability of pair production of particles by an external electromagnetic field has been calculated on the basis of the exact solutions. We have also estimated the imaginary part of the constant and uniform electromagnetic field. The nonlinear corrections to the Maxwell Lagrangian have been calculated taking into account the vacuum polarization of arbitrary spin particles. The role of electric dipole and magnetic moments of arbitrary spin particles in instability of the vacuum is discussed.Comment: 18 pages, LaTeX, accepted for publication in Ann.Phys.(USA

A measurement of parity-violating gamma-ray asymmetries in polarized cold neutron capture on 35Cl, 113Cd, and 139La

An apparatus for measuring parity-violating asymmetries in gamma-ray emission following polarized cold neutron capture was constructed as a 1/10th scale test of the design for the forthcoming n+p->d+gamma experiment at LANSCE. The elements of the polarized neutron beam, including a polarized 3He neutron spin filter and a radio frequency neutron spin rotator, are described. Using CsI(Tl) detectors and photodiode current mode readout, measurements were made of asymmetries in gamma-ray emission following neutron capture on 35Cl, 113Cd, and 139La targets. Upper limits on the parity-allowed asymmetry $s_n \cdot (k_{\gamma} \times k_n)$ were set at the level of 7 x 10^-6 for all three targets. Parity-violating asymmetries $s_n \cdot k_{\gamma}$ were observed in 35Cl, A_gamma = (-29.1 +- 6.7) x 10^-6, and 139La, A_gamma = (-15.5 +- 7.1) x 10^-6, values consistent with previous measurements.Comment: 19 pages, 4 figures, submitted to Nucl. Instr. and Meth.

New constraints on WIMPs from the Canfranc IGEX dark matter search

The IGEX Collaboration enriched 76Ge double-beta decay detectors are currently operating in the Canfranc Underground Laboratory with an overburden of 2450 m.w.e. A recent upgrade has made it possible to use them in a search for WIMPs. A new exclusion plot has been derived for WIMP-nucleon spin-independent interaction. To obtain this result, 30 days of data from one IGEX detector, which has an energy threshold of ~4 keV, have been considered. These data improve the exclusion limits derived from other germanium diode experiments in the ~50 GeV DAMA region, and show that with a moderate improvement of the background below 10 keV, the DAMA region may be tested with an additional 1 kg-year of exposure.Comment: 7 pages, 2 figures, submitted to Physics Letter

Pulse Shape Discrimination in the IGEX Experiment

The IGEX experiment has been operating enriched germanium detectors in the Canfranc Underground Laboratory (Spain) in a search for the neutrinoless double decay of 76Ge. The implementation of Pulse Shape Discrimination techniques to reduce the radioactive background is described in detail. This analysis has been applied to a fraction of the IGEX data, leading to a rejection of ~60 % of their background, in the region of interest (from 2 to 2.5 MeV), down to ~0.09 c/(keV kg y).Comment: 18 pages, 10 figure

Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment

The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is dedicated to measure with high precision the parity violating asymmetry in the $\gamma$ emission after capture of spin polarized cold neutrons in para-hydrogen. The measurement will determine unambiguously the weak pion-nucleon-nucleon ($\pi NN$) coupling constant {\it f$^1_{\pi}$}Comment: Proceedings of the PANIC'05 Conference, Santa Fe, NM, USA, October 24-28, 2005, 3 pages, 2 figure

From cheek swabs to consensus sequences : an A to Z protocol for high-throughput DNA sequencing of complete human mitochondrial genomes

Background: Next-generation DNA sequencing (NGS) technologies have made huge impacts in many fields of biological research, but especially in evolutionary biology. One area where NGS has shown potential is for high-throughput sequencing of complete mtDNA genomes (of humans and other animals). Despite the increasing use of NGS technologies and a better appreciation of their importance in answering biological questions, there remain significant obstacles to the successful implementation of NGS-based projects, especially for new users. Results: Here we present an ‘A to Z’ protocol for obtaining complete human mitochondrial (mtDNA) genomes – from DNA extraction to consensus sequence. Although designed for use on humans, this protocol could also be used to sequence small, organellar genomes from other species, and also nuclear loci. This protocol includes DNA extraction, PCR amplification, fragmentation of PCR products, barcoding of fragments, sequencing using the 454 GS FLX platform, and a complete bioinformatics pipeline (primer removal, reference-based mapping, output of coverage plots and SNP calling). Conclusions: All steps in this protocol are designed to be straightforward to implement, especially for researchers who are undertaking next-generation sequencing for the first time. The molecular steps are scalable to large numbers (hundreds) of individuals and all steps post-DNA extraction can be carried out in 96-well plate format. Also, the protocol has been assembled so that individual ‘modules’ can be swapped out to suit available resources