The domestication of the probiotic bacterium Lactobacillus acidophilus

Lactobacillus acidophilus is a Gram-positive lactic acid bacterium that has had widespread historical use in the dairy industry and more recently as a probiotic. Although L. acidophilus has been designated as safe for human consumption, increasing commercial regulation and clinical demands for probiotic validation has resulted in a need to understand its genetic diversity. By drawing on large, well-characterised collections of lactic acid bacteria, we examined L. acidophilus isolates spanning 92 years and including multiple strains in current commercial use. Analysis of the whole genome sequence data set (34 isolate genomes) demonstrated L. acidophilus was a low diversity, monophyletic species with commercial isolates essentially identical at the sequence level. Our results indicate that commercial use has domesticated L. acidophilus with genetically stable, invariant strains being consumed globally by the human population

Survey of ultrasound practice amongst podiatrists in the UK

Background: Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies. This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound. Methods: A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK. Results: Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter (n=62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector (n=118, 41%). Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks. Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making (n=81) and guide interventions (steroid injections n=67; nerve blocks n=39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists (n=28) or health professionals (n=18). Few use ultrasound imaging for research (n=7) or education (n=2). Only 32 (11%) respondents (n=20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies. Few respondents (18%) had completed formal post-graduate CASE (Consortium for the Accreditation of Sonographic Education) accredited ultrasound courses. Forty (14%) respondents receive ultrasound mentorship; the majority from fellow podiatrists (n=17) or medical colleagues (n=15). Over half (n=127) who do not have ultrasound mentorship indicated they would like a mentor predominantly for ultrasound imaging. Fifty-five (19%) report they currently provide ultrasound mentorship for others. Conclusions: Understanding the scope of ultrasound practice, the training undertaken and the requirements for mentorship will underpin the development of competencies and recommendations defined by the College of Podiatry to support professional development and ensure safe practice.</p

Gas-mediated charged particle beam processing of nanostructured materials

Gas mediated processing under a charged particle (electron or ion) beam enables direct-write, high resolution surface functionalization, chemical dry etching and chemical vapor deposition of a wide range of materials including catalytic metals, optoelectronic grade semiconductors and oxides. Here we highlight three recent developments of particular interest to the optical materials and nanofabrication communities: fabrication of self-supporting, three dimensional, fluorescent diamond nanostructures, electron beam induced deposition (EBID) of high purity materials via activated chemisorption, and post-growth purification of nanocrystalline EBID-grown platinum suitable for catalysis applications. © 2014 SPIE

First birth following spindle transfer for mitochondrial replacement therapy: hope and trepidation

In this issue, Zhang et al. (2017) report the birth of a healthy boy after mitochondrial replacement therapy (MRT) by spindle transfer to prevent transmission of mitochondrial disease from mother to child. The case was first publicized in the lay press (Hamzelou, 2016; see also editorial by Johnson, 2016) and then presented during the 2016 Annual Meeting of the American Society for Assisted Reproduction (ASRM) in October 2016 (Zhang et al., 2016a). It followed an earlier report of an unsuccessful attempt at MRT by pronuclear transfer by the same group (Zhang et al., 2016b). This world-first birth represents an achievement and a steppingstone, and it has played a role in encouraging the Human Fertilization and Embryology Authority (HFEA) in the UK to issue a final recommendation that the technique ‘be approved for cautious use in specific circumstances’. (http://www.hfea.gov.uk/10559.html) We, the editors, were unanimous in deciding that this paper should be published in RBMO, based on our conviction that the scientific community must be informed of the details of the work in full in order to evaluate it critically and discuss it openly. We decided this despite the fact that the work has weaknesses and limitations in a number of areas. Moreover, although we were able to encourage the authors to include more details of their work in the submission, some uncertainties concerning methodologies and results still remain. Here we outline our concerns regarding the approach and the treatment process described by Zhang and colleagues

Dam inactivation in : prevalence among diverse hyperinvasive lineages

Abstract Background DNA adenine methyltransferase (Dam) activity is absent in many, but not all, disease isolates of Neisseria meningitidis, as a consequence of the insertion of a restriction endonuclease-encoding gene, the 'dam replacing gene' (drg) at the dam locus. Here, we report the results of a survey to assess the prevalence of drg in a globally representative panel of disease-associated meningococci. Results Of the known meningococcal hyper-invasive lineages investigated, drg was absent in all representatives of the ST-8 and ST-11 clonal complexes tested, but uniformly present in the representatives of the other hyper-invasive lineages present in the isolate collection (the ST-1, ST-4, ST-5, ST-32 and ST-41/44 clonal complexes). The patterns of sequence diversity observed in drg were consistent with acquisition of this gene from a source organism with a different G+C content, at some time prior to the emergence of present-day meningococcal clonal complexes, followed by spread through the meningococcal population by horizontal genetic exchange. During this spread a number of alleles have arisen by mutation and intragenic recombination. Conclusion These findings are consistent with the idea that possession of the drg gene may contribute to the divergence observed among meningococcal clonal complexes, but does not have a direct mechanistic involvement in virulence.</p

A novel instrument to measure differential ablation of meteorite samples and proxies: The Meteoric Ablation Simulator (MASI)

On entering the Earth’s atmosphere, micrometeoroids partially or completely ablate, leaving behind layers of metallic atoms and ions. The relative concentration of the various metal layers is not well explained by current models of ablation. Furthermore, estimates of the total flux of cosmic dust and meteoroids entering the Earth’s atmosphere vary over two orders of magnitude. To better constrain these estimates and to better model the metal layers in the mesosphere, an experimental meteoric Ablation Simulator (MASI) has been developed. Interplanetary Dust Particle (IDP) analogs are subjected to temperature profiles simulating realistic entry heating, to ascertain the differential ablation of relevant metal species. MASI is the first ablation experiment capable of simulating detailed mass, velocity, and entry angle-specific temperature profiles whilst simultaneously tracking the resulting gas-phase ablation products in a time resolved manner. This enables the determination of elemental atmospheric entry yields which consider the mass and size distribution of IDPs. The instrument has also enabled the first direct measurements of differential ablation in a laboratory setting

Comparison of the microalgal community within fast ice at two sites along the Ross Sea coast, Antarctica

Diverse microbial communities survive within the sea ice matrix and are integral to the energy base of the Southern Ocean. Here we describe initial findings of a four season survey (between 1999-2004) of community structure and biomass of microalgae within the sea ice and in the underlying water column at Cape Evans and Cape Hallett, in the Ross Sea, Antarctica as part of the Latitudinal Gradient Project. At Cape Evans, bottom-ice chlorophyll a levels ranged from 4.4 to 173 mg Chl a m-2. Dominant species were Nitzschia stellata, N. lecointei, and Entomoneis kjellmanii, while the proportion of Berkeleya adeliensis increased steadily during spring. Despite being obtained later in the season, the Cape Hallett data show considerably lower standing stocks of chlorophyll ranging from 0.11 to 36.8 mg Chl a m-2. This difference was attributed to a strong current, which may have ablated much of the bottom ice biomass and provided biomass to the water below. This loss of algae from the bottom of the ice may explain why the ice community contributed only 2% of the standing stock in the total water column. Dominant species at Cape Hallett were Nitzschia stellata, Fragilariopsis curta and Cylindrotheca closterium. The low biomass at Cape Hallett and the prevalence of smaller-celled diatoms in the bottom ice community indicate that the ice here is more typical of pack ice than fast ice. Further data will allow us to quantify and model the extent to which ice-driven dynamics control the structure and function of the sea ice ecosystem and to assess its resilience to changing sea ice conditions. © Antarctic Science Ltd

Spatially and genetically distinct African trypanosome virulence variants defined by host interferon-g response

We describe 2 spatially distinct foci of human African trypansomiasis in eastern Uganda. The Tororo and Soroti foci of &lt;i&gt;Trypanosoma brucei rhodesiense&lt;/i&gt; infection were genetically distinct as characterized by 6 microsatellite and 1 minisatellite polymorphic markers and were characterized by differences in disease progression and host-immune response. In particular, infections with the Tororo genotype exhibited an increased frequency of progression to and severity of the meningoencephalitic stage and higher plasma interferon (IFN)–γ concentration, compared with those with the Soroti genotype. We propose that the magnitude of the systemic IFN-γ response determines the time at which infected individuals develop central nervous system infection and that this is consistent with the recently described role of IFN-γ in facilitating blood-brain barrier transmigration of trypanosomes in an experimental model of infection. The identification of trypanosome isolates with differing disease progression phenotypes provides the first field-based genetic evidence for virulence variants in T. &lt;i&gt;brucei rhodesiense&lt;/i&gt;

Viral Hepatitis and Rapid Diagnostic Test Based Screening for HBsAg in HIV-infected Patients in Rural Tanzania.

\ud \ud Co-infection with hepatitis B virus (HBV) is highly prevalent in people living with HIV in Sub-Saharan Africa. Screening for HBV surface antigen (HBsAg) before initiation of combination antiretroviral therapy (cART) is recommended. However, it is not part of diagnostic routines in HIV programs in many resource-limited countries although patients could benefit from optimized antiretroviral therapy covering both infections. Screening could be facilitated by rapid diagnostic tests for HBsAg. Operating experience with these point of care devices in HIV-positive patients in Sub-Saharan Africa is largely lacking. We determined the prevalence of HBV and Hepatitis C virus (HCV) infection as well as the diagnostic accuracy of the rapid test device Determine HBsAg in an HIV cohort in rural Tanzania. Prospectively collected blood samples from adult, HIV-1 positive and antiretroviral treatment-naïve patients in the Kilombero and Ulanga antiretroviral cohort (KIULARCO) in rural Tanzania were analyzed at the point of care with Determine HBsAg, a reference HBsAg EIA and an anti-HCV EIA. Samples of 272 patients were included. Median age was 38 years (interquartile range [IQR] 32-47), 169/272 (63%) subjects were females and median CD4+ count was 250 cells/µL (IQR 97-439). HBsAg was detected in 25/272 (9.2%, 95% confidence interval [CI] 6.2-13.0%) subjects. Of these, 7/25 (28%) were positive for HBeAg. Sensitivity of Determine HBsAg was rated at 96% (95% CI 82.8-99.6%) and specificity at 100% (95% CI, 98.9-100%). Antibodies to HCV (anti-HCV) were found in 10/272 (3.7%, 95% CI 2.0-6.4%) of patients. This study reports a high prevalence of HBV in HIV-positive patients in a rural Tanzanian setting. The rapid diagnostic test Determine HBsAg is an accurate assay for screening for HBsAg in HIV-1 infected patients at the point of care and may further help to guide cART in Sub-Saharan Africa