Bioprospecting for and the applications of halophilic acidophiles in bioleaching operations

The economic recovery of metals from sulfide ores has become a topic of increasing interest due to the escalating demand for critical minerals and the reducing grade of available ores. Bioleaching is the use of acidophilic iron and sulfur-oxidising microorganisms to facilitate the extraction of base metals from primary sulfide ores and tailings. One significant issue limiting the use of bioleaching is the availability of freshwater due to the sensitivity of these microbes to chloride. The use of saline tolerant acidophilic iron- and-sulfur oxidising microorganisms will go a long way to addressing this issue. There are three possible means of sourcing suitable microorganisms; adaptation, genetic engineering and bioprospecting, with bioprospecting showing the greatest possibilities. Bioprospecting in search of native organisms for bioleaching operations has led researchers to numerous locations around the world and the isolation of iron- and sulfur-oxidising acidophiles that are capable of tolerating high levels of salinity has been of particular interest in these investigations

Klebsiella aerogenes adhesion behaviour during biofilm formation on monazite

The adsorption behaviour of micro-organisms during the initial attachment stage of biofilm formation affects subsequent stages. The available area for attachment and the chemophysical properties of a surface affect microbial attachment performance. This study focused on the initial attachment behaviour of Klebsiella aerogenes on monazite by measuring the ratio of planktonic against sessile subpopulations (P:S ratio), and the potential role of extracellular DNA (eDNA). eDNA production, effects of physicochemical properties of the surface, particle size, total available area for attachment, and the initial inoculation size on the attachment behaviour were tested. K. aerogenes attached to monazite immediately after exposure to the ore; however, the P:S ratio significantly (p = 0.05) changed in response to the particle size, available area, and inoculation size. Attachment occurred preferentially on larger-sized (~50 µm) particles, and either decreasing the inoculation size or increasing the available area further promoted attachment. Nevertheless, a portion of the inoculated cells always remained in a planktonic state. K. aerogenes produced lower eDNA in response to the changed surface chemical properties when monazite was replaced by xenotime. Using pure eDNA to cover the monazite surface significantly (p ≤ 0.05) hindered bacterial attachment due to the repulsive interaction between the eDNA layer and bacteria

Effect of community-led delivery of HIV self-testing on HIV testing and antiretroviral therapy initiation in Malawi: A cluster-randomised trial

BACKGROUND: Undiagnosed HIV infection remains substantial in key population subgroups including adolescents, older adults, and men, driving ongoing transmission in sub-Saharan Africa. We evaluated the impact, safety, and costs of community-led delivery of HIV self-testing (HIVST), aiming to increase HIV testing in underserved subgroups and stimulate demand for antiretroviral therapy (ART). METHODS AND FINDINGS: This cluster-randomised trial, conducted between October 2018 and July 2019, used restricted randomisation (1:1) to allocate 30 group village head clusters in Mangochi district, Malawi to the community-led HIVST intervention in addition to the standard of care (SOC) or the SOC alone. The intervention involved mobilising community health groups to lead the design and implementation of 7-day HIVST campaigns, with cluster residents (≥15 years) eligible for HIVST. The primary outcome compared lifetime HIV testing among adolescents (15 to 19 years) between arms. Secondary outcomes compared: recent HIV testing (in the last 3 months) among older adults (≥40 years) and men; cumulative 6-month incidence of ART initiation per 100,000 population; knowledge of the preventive benefits of HIV treatment; and HIV testing stigma. Outcomes were measured through a post-intervention survey and at neighboring health facilities. Analysis used intention-to-treat for cluster-level outcomes. Community health groups delivered 24,316 oral fluid-based HIVST kits. The survey included 90.2% (3,960/4,388) of listed participants in the 15 community-led HIVST clusters and 89.2% (3,920/4,394) of listed participants in the 15 SOC clusters. Overall, the proportion of men was 39.0% (3,072/7,880). Most participants obtained primary-level education or below, were married, and reported a sexual partner. Lifetime HIV testing among adolescents was higher in the community-led HIVST arm (84.6%, 770/910) than the SOC arm (67.1%, 582/867; adjusted risk difference [RD] 15.2%, 95% CI 7.5% to 22.9%; p < 0.001), especially among 15 to 17 year olds and boys. Recent testing among older adults was also higher in the community-led HIVST arm (74.5%, 869/1,166) than the SOC arm (31.5%, 350/1,111; adjusted RD 42.1%, 95% CI 34.9% to 49.4%; p < 0.001). Similarly, the proportions of recently tested men were 74.6% (1,177/1,577) and 33.9% (507/1,495) in the community-led HIVST and SOC arms, respectively (adjusted RD 40.2%, 95% CI 32.9% to 47.4%; p < 0.001). Knowledge of HIV treatment benefits and HIV testing stigma showed no differences between arms. Cumulative incidence of ART initiation was respectively 305.3 and 226.1 per 100,000 population in the community-led HIVST and SOC arms (RD 72.3, 95% CI -36.2 to 180.8; p = 0.18). In post hoc analysis, ART initiations in the 3-month post-intervention period were higher in the community-led HIVST arm than the SOC arm (RD 97.7, 95% CI 33.4 to 162.1; p = 0.004). HIVST uptake was 74.7% (2,956/3,960), with few adverse events (0.6%, 18/2,955) and at US$5.70 per HIVST kit distributed. The main limitations include the use of self-reported HIV testing outcomes and lack of baseline measurement for the primary outcome. CONCLUSIONS: In this study, we found that community-led HIVST was effective, safe, and affordable, with population impact and coverage rapidly realised at low cost. This approach could enable community HIV testing in high HIV prevalence settings and demonstrates potential for economies of scale and scope. TRIAL REGISTRATION: Clinicaltrials.gov NCT03541382

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Examining the Osmotic Response of Acidihalobacter aeolianus after Exposure to Salt Stress

Acidihalobacter aeolianus is an acidophilic, halo-tolerant organism isolated from a marine environment near a hydrothermal vent, an ecosystem whereby levels of salinity and total dissolved salts are constantly fluctuating creating ongoing cellular stresses. In order to survive these continuing changes, the synthesis of compatible solutes&mdash;also known as organic osmolytes&mdash;is suspected to occur, aiding in minimising the overall impact of environmental instability. Previous studies on A. aeolianus identified genes necessary for the accumulation of proline, betaine and ectoine, which are known to act as compatible solutes in other halophilic species. In this study, the impact of increasing the osmotic stress as well as the toxic ion effect was investigated by subjecting A. aeolianus to concentrations of NaCl and MgSO4 up to 1.27 M. Exposure to high concentrations of Cl&minus; resulted in the increase of ectC expression in log-phase cells with a corresponding accumulation of ectoine at stationary phase. Osmotic stress via MgSO4 exposure did not trigger the same up-regulation of ectC or accumulation of ectoine, indicating the transcriptionally regulated response against osmotic stress was induced by chloride toxicity. These findings have highlighted how the adaptive properties of halo-tolerant organisms in acidic environments are likely to differ and are dependent on the initial stressor

The Epidemiology of Ankle Sprains In United States High School Sports, 2011/12-2018/19 Academic Years

Context:Continued monitoring of ankle sprain rates and distributions is needed to assess temporal patterns and gauge how changes in incidence may be associated with prevention efforts. Objective:Describe the epidemiology of ankle sprains in 15 high school sports during the 2011/12–2018/19 school years. Study Design: Descriptive epidemiology study. Setting: Online injury surveillance from high school sports. Patients:High school athletes who participated in practices and competitions during the 2011/12–2018/19 school years. Methods: A convenience sample of high school athletic trainers (ATs) provided injury and athlete-exposure (AE) data to the National High School Sports-Related Injury Surveillance Study (HS RIOTM). Ankle sprain rates per 10,000AE with 95% confidence intervals (CI) and distributions were calculated. Yearly rates were examined overall, by event type, injury mechanism, and recurrence. Results: Overall, 9,320 ankle sprains were reported (overall rate=2.95/10,000AE; 95%CI: 2.89–3.01). The highest sport-specific rates were reported in girls\u27 basketball (5.32/10,000AE), boys\u27 basketball (5.13/10,000AE), girls\u27 soccer (4.96/10,000AE), and boys\u27 football (4.55/10,000AE). Most ankle sprains occurred during competition (54.3%) and were due to contact with another person (39.5%) and non-contact (35.0%). Also, 14.5% of injuries were noted as recurrent. Across the included academic years, ankle sprain rates generally increased. Compared to the 2011/12 academic year, rates in the 2018/19 academic year overall were 22% higher; non-contact-related and recurrent ankle sprain rates also generally increased, with 91% and 29% increases, respectively. Conclusions:: Time trends suggest ankle sprain rates have increased across the past decade, particularly among those with non-contact-related mechanisms; this contrasts previous research suggesting decreases in incidence. Findings may pinpoint specific etiological factors that should direct prevention efforts. This includes considering both person-contact and non-contact mechanisms through mitigating illegal contact through rule changes and enforcement, alongside bracing and proprioceptive and balance training programs

Examining the Osmotic Response of <i>Acidihalobacter aeolianus</i> after Exposure to Salt Stress

Acidihalobacter aeolianus is an acidophilic, halo-tolerant organism isolated from a marine environment near a hydrothermal vent, an ecosystem whereby levels of salinity and total dissolved salts are constantly fluctuating creating ongoing cellular stresses. In order to survive these continuing changes, the synthesis of compatible solutes—also known as organic osmolytes—is suspected to occur, aiding in minimising the overall impact of environmental instability. Previous studies on A. aeolianus identified genes necessary for the accumulation of proline, betaine and ectoine, which are known to act as compatible solutes in other halophilic species. In this study, the impact of increasing the osmotic stress as well as the toxic ion effect was investigated by subjecting A. aeolianus to concentrations of NaCl and MgSO4 up to 1.27 M. Exposure to high concentrations of Cl− resulted in the increase of ectC expression in log-phase cells with a corresponding accumulation of ectoine at stationary phase. Osmotic stress via MgSO4 exposure did not trigger the same up-regulation of ectC or accumulation of ectoine, indicating the transcriptionally regulated response against osmotic stress was induced by chloride toxicity. These findings have highlighted how the adaptive properties of halo-tolerant organisms in acidic environments are likely to differ and are dependent on the initial stressor

Both KH and non-KH domain sequences are required for polyribosome association of Scp160p in yeast

Scp160p is a 160 kDa RNA-binding protein in yeast previously demonstrated to associate with specific messages as an mRNP component of both soluble and membrane-bound polyribosomes. Although the vast majority of Scp160p sequence consists of 14 closely spaced KH domains, comparative sequence analyses also demonstrate the presence of a potential nuclear localization sequence located between KH domains 3 and 4, as well as a 110 amino acid non-KH N-terminal region that includes a potential nuclear export sequence (NES). As a step toward investigating the structure/function relationships of Scp160p, we generated two truncated alleles, FLAG.SCP160ΔN1, encoding a protein product that lacks the first 74 amino acids, including the potential NES, and FLAG.SCP160ΔC1, encoding a protein product that lacks the final KH domain (KH14). We report here that the N-truncated protein, expressed as a green fluorescent protein fusion in yeast, remains cytoplasmic, with no apparent nuclear accumulation. Biochemical studies further demonstrate that although the N-truncated protein remains competent to form RNPs, the C-truncated protein does not. Furthermore, polyribosome association is severely compromised for both truncated proteins. Perhaps most important, both truncated alleles appear only marginally functional in vivo, as demonstrated by the inability of each to complement scp160/eap1 synthetic lethality in a tester strain. Together, these data challenge the notion that Scp160p normally shuttles between the nucleus and cytoplasm, and further implicate polyribosome association as an essential component of Scp160p function in vivo. Finally, these data underscore the vital roles of both KH and non-KH domain sequences in Scp160p

A fluorescent biosensor reveals conformational changes in human immunoglobulin E Fc: Implications for mechanisms of receptor binding, inhibition, and allergen recognition

IgE binding to its high affinity receptor Fc?RI on mast cells and basophils is a key step in the mechanism of allergic disease and a target for therapeutic intervention. Early indications that IgE adopts a bent structure in solution have been confirmed by recent x-ray crystallographic studies of IgEFc, which further showed that the bend, contrary to expectation, is enhanced in the crystal structure of the complex with receptor. To investigate the structure of IgEFc and its conformational changes that accompany receptor binding in solution, we created a Förster resonance energy transfer (FRET) biosensor using biologically encoded fluorescent proteins fused to the N- and C-terminal IgEFc domains (C?2 and C?4, respectively) together with the theoretical basis for quantitating its behavior. This revealed not only that the IgEFc exists in a bent conformation in solution but also that the bend is indeed enhanced upon Fc?RI binding. No change in the degree of bending was seen upon binding to the B cell receptor for IgE, CD23 (Fc?RII), but in contrast, binding of the anti-IgE therapeutic antibody omalizumab decreases the extent of the bend, implying a conformational change that opposes Fc?RI engagement. HomoFRET measurements further revealed that the (C?2)2 and (C?4)2 domain pairs behave as rigid units flanking the conformational change in the C?3 domains. Finally, modeling of the accessible conformations of the two Fab arms in Fc?RI-bound IgE revealed a mutual exclusion not seen in IgG and Fab orientations relative to the membrane that may predispose receptor-bound IgE to cross-linking by allergens