Isolation of salt-tolerant, iron-oxidising, acidophilic bacteria and assessment of their bioleaching potential at high salinity

The occurrence of chemoautotrophic, acidophilic bacteria in the marine environment has been widely noted and they have been implicated in the biogeochemical cycling of iron and biodeterioration of iron-containing structures in the oceans. However, the isolation, molecular ecology, growth profiles and physiological responses of these bacteria at elevated salt levels have rarely been described, despite widespread interest in their unique metabolic capacity. These bacteria may have a potential application in the extraction of metals via bioleaching of salt contaminated ores or to facilitate the use of seawater in the bioleaching process. Traditional bioleaching microorganisms cannot be used in these cases due to the toxicity of elevated salt concentrations. In this study, three strains of halotolerant gram-positive, rod shaped, acidophilic bacteria were isolated from estuarine and coastal areas, two of which were novel species. Enrichment cultures were set up using pyrite medium of different salinities with sediment and seawater samples from a variety of metal contaminated areas exposed to the sea or brackish water. These enrichment cultures were then further purified using end-point dilution culture methods and the 16S rRNA genes were sequenced and phylogeny assessed. The growth characteristics, morphology and growth profiles on a variety of metaliferrous ore samples of the strains were characterised. The strains exhibited autotrophic growth on a variety of iron and sulphur-containing compounds, heterotrophic growth on yeast extract medium as well as mixotrophic growth on a combination of these substrates. The strains grew optimally with 30gl" sea salts added to the medium, at a pH of 2.0 and a temperature of 37"C. Two of these isolated bacteria represent novel species in the genera Suffibbacillus and Alicyclobacillus. High final iron dissolution levels were demonstrated after biooxidation of Lihir gold ore and Escondida Copper ore in medium with 30 gl" sea salts and 2% ore for 30 days. Bacterium 4G mediated 66.10%, 5C 100% and Cligga 88.86% dissolution of the total iron present in the Lihir sample after 30 days, while bacterium 4G mediated 52.63%, 5C 60% and Cligga 49.75% dissolution of the total iron present in the Escondida samples after 30 days. The growth characteristics displayed by these bacterial strains demonstrate their potential application in high salinity bioleaching operation

How Diverse Librarians Increased Access to Electronic Journals, Developed a Print/Electronic Collection Development Policy and Preserved the Collection

This poster reports on a project initiated to establish a framework for evaluating our serials collection in order to preserve the collection from a flat budget and ever increasing serial costs and to meet patron demand for expanded access to electronic resources. An additional outcome was the development of a combined print and electronic serials collection development policy. A Journals Committee was formed to assess the value and most appropriate format(s) of individual journal titles. Methods used included a mathematical formula calculating a title\u27s relative value and a faculty survey soliciting most-used titles and preferred format. Faculty department heads were asked to evaluate holdings in their subject specialty. Faculty publication patterns, usage statistics, and interlibrary loan (ILL) data were examined. Information was weighted and used to develop an assessment tool to establish a title\u27s value. The results of this methodology were applied to the 2005 serials renewal process

Multiplex antibiotic susceptibility testing of urinary tract infections using an electrochemical lab-on-a-chip

Urinary tract infections (UTIs) represent the most prevalent type of outpatient infection, with significant adverse health and economic burdens. Current culture-based antibiotic susceptibility testing can take up to 72 h resulting in ineffective prescription of broad-spectrum antibiotics, poor clinical outcomes and development of further antibiotic resistance. We report an electrochemical lab-on-a-chip (LOC) for testing samples against seven clinically-relevant antibiotics. The LOC contained eight chambers, each housing an antibiotic-loaded hydrogel (cephalexin, ceftriaxone, colistin, gentamicin, piperacillin, trimethoprim, vancomycin) or antibiotic-free control, alongside a resazurin bulk-modified screen-printed electrode for electrochemical detection of metabolically active bacteria using differential pulse voltammetry. Antibiotic susceptibility in simulated UTI samples or donated human urine with either Escherichia coli or Klebsiella pneumoniae could be established within 85 min. Incorporating electrochemical detection onto a LOC provides an inexpensive, simple method for the sensitive determination of antibiotic susceptibility that is significantly faster than using a culture-based approach

Integration of Medical Informatics Curriculum into Problem-Based Learning (PBL) Course for 1st Year Medical Students

Himmelfarb Health Sciences Library librarians developed and taught Introduction to Medical Informatics to first-year medical students through the 2002/03 school year. In 2003/04, this course was restructured and integrated into the Problem-Based Learning (PBL) course taken by all first-year medical students. The goal was to improve resource selection and search skills, provide point-of-use learning and instruction, and to enhance the student experience. Librarians were assigned to individual PBL groups to act as advisors and guided the students through the informatics-related curriculum

Empowering Faculty to Choose: Open Access and Alternative Publishing

Himmelfarb Health Sciences Library librarians initiated an effort to increase awareness of alternative publishing venues which exist outside the commercial arena; to encourage faculty to investigate electronic publishing alternatives; and to provide a connection to open access initiatives. George Washington University now participates in four open access initiatives and interest is growing among GWU faculty

Rapid antibiotic susceptibility testing using resazurin bulk modified screen-printed electrochemical sensing platforms

Urinary tract infections (UTIs) are one of the most common types of bacterial infection. UTIs can be associated with multidrug resistant bacteria and current methods of determining an effective antibiotic for UTIs can take up to 48 hours, which increases the chances of a negative prognosis for the patient. In this paper we report for the first time, the fabrication of resazurin bulk modified screen-printed macroelectrodes (R-SPEs) demonstrating them to be effective platforms for the electrochemical detection of antibiotic susceptibility in complicated UTIs. Using differential pulse voltammetry (DPV), resazurin was able to be detected down to 15.6 μM. R-SPEs were utilised to conduct antibiotic susceptibility testing (AST) of E. coli (ATCC® 25922) to the antibiotic gentamicin sulphate using DPV to detect the relative concentrations of resazurin between antibiotic treated bacteria, and bacteria without antibiotic treatment. Using R-SPEs, antibiotic susceptibility was determined after a total elapsed time of 90 minutes including the inoculation of the artificial urine, preincubation and testing time. The use of electrochemistry as a phenotypic means of identifying an effective antibiotic to treat a complicated UTI offers a rapid and accurate alternative to culture based methods for AST with R-SPEs offering an inexpensive and simpler alternative to other AST methods utilising electrochemical based approaches

Antimicrobial Drug–Resistant Escherichia coli from Humans and Poultry Products, Minnesota and Wisconsin, 2002–2004

Similarities were found between drug-resistant E. coli from humans and poultry products

Mapping trabecular disconnection "hotspots" in aged human spine and hip

Trabecular bone disconnection is an independent factor in age-related skeletal failure where real termini (ReTm; rare in youth) may cause weakness disproportionate to tissue loss, yet their structural contribution at vulnerable locations remains uncertain. ReTm (previously recorded at the iliac crest) were mapped in "normal" aged vertebral bodies (T11-L5 autopsy; 20 females, 10 males) and corresponding proximal femora (autopsy; 10 females). Results were compared with biomechanically failed femora from orthopaedic subjects aged >. 58. yr (osteoporosis OP, 10 females; osteoarthritis OA, 10 females). A novel direct 2D/3D histological method was applied to large, thick (300. μm) slices superficially silver-stained to separate ReTm (unstained) from apparent termini (planar artefacts, brown). Light microscope field co-ordinates enabled ReTm mapping and statistical testing relative to i) sex, ii) tissue sector and iii) slicing plane. In men ReTm populations were small and random while in women they were large and sector-specific. In vertebrae they clustered anterior/superior being rare posterior/inferior; in the femoral head they concentrated distal/superior and also near the fovea, being fewer distal/inferior. A distribution polarity was evident with 100% more ReTm observed transversely (i.e., on tensile-related cross struts) than longitudinally (i.e., on compression-related vertical struts). Their numbers rose in OP (BV/TV. . 14%), remaining polarised and sector-specific in OP only. Comparative experimentation by marrow elution of an OP animal model demonstrated "floating segments" as a possible outcome. Conclusions were supported statistically that trabecular disconnection "hotspots" at vulnerable locations are sex- and sector-specific, mainly transaxial, and subject to disease modulation

An Inducible and Reversible Mouse Genetic Rescue System

Inducible and reversible regulation of gene expression is a powerful approach for uncovering gene function. We have established a general method to efficiently produce reversible and inducible gene knockout and rescue in mice. In this system, which we named iKO, the target gene can be turned on and off at will by treating the mice with doxycycline. This method combines two genetically modified mouse lines: a) a KO line with a tetracycline-dependent transactivator replacing the endogenous target gene, and b) a line with a tetracycline-inducible cDNA of the target gene inserted into a tightly regulated (TIGRE) genomic locus, which provides for low basal expression and high inducibility. Such a locus occurs infrequently in the genome and we have developed a method to easily introduce genes into the TIGRE site of mouse embryonic stem (ES) cells by recombinase-mediated insertion. Both KO and TIGRE lines have been engineered for high-throughput, large-scale and cost-effective production of iKO mice. As a proof of concept, we have created iKO mice in the apolipoprotein E (ApoE) gene, which allows for sensitive and quantitative phenotypic analyses. The results demonstrated reversible switching of ApoE transcription, plasma cholesterol levels, and atherosclerosis progression and regression. The iKO system shows stringent regulation and is a versatile genetic system that can easily incorporate other techniques and adapt to a wide range of applications

Utilising copper screen-printed electrodes (CuSPE) for the electroanalytical sensing of sulfide

© The Royal Society of Chemistry 2016.A mediatorless sulfide electrochemical sensing platform utilising a novel nanocopper-oxide screen-printed electrodes (CuSPE) is reported for the first time. The state-of-the-art screen-printed electrochemical sensors demonstrate their capability to quantify sulfide within both the presence and absence of an array of interferents with good levels of sensitivity and repeatability. The direct sensing (using linear sweep voltammetry) of sulfide utilising the CuSPEs provides a mediatorless approach for the detection of sulfide, yielding useful analytical signatures that can be successfully quantified. The proposed novel protocol using the CuSPEs is successfully applied to the sensing of sulfide within drinking water exhibiting a high level of recovery