Living on the edge: regional distribution and retracting range of the jaguar (Panthera onca)

Vivir al límite: distribución regional y superficie ocupada por el jaguar en retroceso (Panthera onca) Para conservar la biodiversidad, es necesario entender cómo se distribuyen las especies y qué variables ambientales determinan dicha distribución. Los cambios inducidos por el hombre en la ocupación del suelo y la pérdida de hábitat ponen en peligro a numerosas especies de todo el mundo, especialmente a grandes carnívoros. Diferenciar la influencia del clima y la de los usos del suelo en la distribución de jaguar (Panthera onca) es importante para su conservación. Esta especie, que tradicionalmente se distribuía desde los Estados Unidos hasta el sur de Argentina, ha visto reducida su distribución a escala regional y local. En este trabajo predecimos el rango de distribución de la especie utilizando registros de presencia histórica, variables climáticas y algoritmos predictivos obtenidos con MaxEnt. Nos centramos especialmente en su límite más austral en Argentina para indicar los límites históricos de esta especie y describir el nicho que ocupa actualmente en estas poblaciones marginales. Para estimar el efecto de las acciones antrópicas, utilizamos una capa de ocupación del suelo para limitar la distribución del jaguar. Recopilamos una buena cantidad de registros de presencia en todo el área de distribución histórica de la especie y estimamos una distribución regional histórica desde la Patagonia hasta los –50° de latitud. Nuestros resultados ponen de manifiesto que el área de distribución del jaguar se está contrayendo de forma alarmante en el límite meridional y también en el septentrional, y que los cambios de ocupación y de uso del suelo son una amenaza para la especie. Tras restar del nicho estudiado la ocupación del suelo que no es adecuada, descubrimos que la superficie idónea para el jaguar desde el punto de vista ambiental en la zona del estudio se ha reducido hasta el 5,2% de su tamaño original. Por consiguiente, advertimos del elevado riesgo de extinción que acecha al jaguar en Argentina.Vivir al límite: distribución regional y superficie ocupada por el jaguar en retroceso (Panthera onca) Para conservar la biodiversidad, es necesario entender cómo se distribuyen las especies y qué variables ambientales determinan dicha distribución. Los cambios inducidos por el hombre en la ocupación del suelo y la pérdida de hábitat ponen en peligro a numerosas especies de todo el mundo, especialmente a grandes carnívoros. Diferenciar la influencia del clima y la de los usos del suelo en la distribución de jaguar (Panthera onca) es importante para su conservación. Esta especie, que tradicionalmente se distribuía desde los Estados Unidos hasta el sur de Argentina, ha visto reducida su distribución a escala regional y local. En este trabajo predecimos el rango de distribución de la especie utilizando registros de presencia histórica, variables climáticas y algoritmos predictivos obtenidos con MaxEnt. Nos centramos especialmente en su límite más austral en Argentina para indicar los límites históricos de esta especie y describir el nicho que ocupa actualmente en estas poblaciones marginales. Para estimar el efecto de las acciones antrópicas, utilizamos una capa de ocupación del suelo para limitar la distribución del jaguar. Recopilamos una buena cantidad de registros de presencia en todo el área de distribución histórica de la especie y estimamos una distribución regional histórica desde la Patagonia hasta los –50° de latitud. Nuestros resultados ponen de manifiesto que el área de distribución del jaguar se está contrayendo de forma alarmante en el límite meridional y también en el septentrional, y que los cambios de ocupación y de uso del suelo son una amenaza para la especie. Tras restar del nicho estudiado la ocupación del suelo que no es adecuada, descubrimos que la superficie idónea para el jaguar desde el punto de vista ambiental en la zona del estudio se ha reducido hasta el 5,2% de su tamaño original. Por consiguiente, advertimos del elevado riesgo de extinción que acecha al jaguar en Argentina.To preserve biodiversity we need to understand how species are distributed and which aspects of the environment determine these distributions. Human–induced changes in land–cover and loss of habitat threaten many species, particularly large carnivores, in many parts of the world. Differentiating the influence of climate and human land use on the distribution of the jaguar (Panthera onca) is important for the species’ conservation. Historically distributed from the United States to southern Argentina, the jaguar has seen its distribution range decreased at regional and local scales. Here we predict the species’ distribution range using historical records of its presence, climate variables, and MaxEnt predictive algorithms. We focus especially on its southernmost limit in Argentina to indicate the historical limits of this species, and describe its present niche in these edge populations. To estimate the effect of human activity we used a raster of land cover to restrict the jaguar’s distribution. We collected a large amount of presence records through the species’ historical range, and estimated a historical regional distribution ranging from Patagonia up to latitude –50°S. Our findings show the range of the jaguar is decreasing severely in its southern limit and also in its northern limit, and that changes in land cover/use are threats to the species. After subtracting non–suitable land–cover from the studied niche, we found the environmentally suitable area for the jaguar in the study area has decreased to 5.2% of its original size. We thus warn of the high extinction risk of the jaguar in Argentina

Synthesis of polymer Janus particles with tunable wettability profiles as potent solid surfactants to promote gas delivery in aqueous reaction media

Janus particles exhibit a strong tendency to directionally assemble and segregate to interfaces and thus offer advantages as colloidal analogues of molecular surfactants to improve the stability of multiphasic mixtures. Investigation and application of the unique adsorption properties require synthetic procedures that enable careful design and reliable control over the particles’ asymmetric chemistry and wettability profiles with high morphological uniformity across a sample. Herein, we report on a novel one-step synthetic approach for the generation of amphiphilic polymer Janus particles with highly uniform and tunable wettability contrasts, which is based on using reconfigurable bi-phasic Janus emulsions as versatile particle scaffolds. Two phase-separated acrylate oils were used as the constituent droplet phases and transformed into their solidified Janus particle replicas via UV-induced radical polymerization. Using Janus emulsions as particle precursors offers the advantage that their internal droplet geometry can be fine-tuned by changing the force balance of surface tensions acting at the individual interfaces via surfactants or the volume ratio of the constituent phases. In addition, preassembled functional surfactants at the droplet interfaces can be locked in position upon polymerization, which enables both access toward postfunctionalization reaction schemes and the generation of highly uniform Janus particles with adjustable wettability profiles. Depending on the particle morphology and wettability, their interfacial position can be adjusted, which allows us to stabilize either air bubbles-in-water or water droplets-in-air (liquid marbles). Motivated by the interfacial activity of the particles and particularly the longevity of the resulting particle-stabilized air-in-water bubbles, we explored their ability to promote the delivery of oxygen inside a liquid-phase reaction medium, namely, for the heterogeneous Au-NP-mediated catalytic oxidation of d-glucose. We observed a 2.2-fold increase in the reaction rate attributed to the increase of the local concentration of oxygen around catalysts, thus showcasing a new strategy to overcome the limited solubility of gases in aqueous reaction media

Toward efficient synthesis of porous all-carbon-based nanocomposites for enantiospecific separation

Chiral separation and asymmetric synthesis and catalysis are crucial processes for obtaining enantiopure compounds, which are especially important in the pharmaceutical industry. The efficiency of the separation processes is readily increased by using porous materials as the active material can interact with a larger surface area. Silica, metal–organic frameworks, or chiral polymers are versatile porous materials that are established in chiral applications, but their instability under certain conditions in some cases requires the use of more stable porous materials such as carbons. In addition to their stability, porous carbon materials can be tailored for their ability to adsorb and catalytically activate different chemical compounds from the liquid and the gas phase. The difficulties imposed by the functionalization of carbons with chiral species were tackled in the past by carbonizing chiral ionic liquids (CILs) together with a template to create pores, which results in the entire body of a material that is built up from the precursor. To increase the atomic efficiency of ionic liquids for better economic utilization of CILs, the approach presented here is based on the formation of a composite between CIL-derived chiral carbon and a pristine carbon material obtained from carbohydrate precursors. Two novel enantioselective carbon composite materials are applied for the chiral recognition of molecules in the gas phase, as well as in solution. The enantiomeric ratio of the l-composite for phenylalanine from the solution was (L/D) = 8.4, and for 2-butanol from the gas phase, it was (S/R) = 1.3. The d-composite showed an opposite behavior, where the enantiomeric ratio for phenylalanine was (D/L) = 2.7, and for 2-butanol from the gas phase, it was (R/S) = 1.3

Carbapenem-resistant Enterobacterales in patients with bacteraemia at tertiary academic hospitals in South Africa, 2019 - 2020: An update

Background. The emergence of carbapenem-resistant Enterobacterales (CRE) has become a serious and significant public health threat worldwide, owing to the limited antimicrobial therapy options, and the elevated mortality rates associated with these infections. Objectives. To present an update on the epidemiology of CRE bloodstream infections among hospitalised patients reported under the Group for Enteric, Respiratory and Meningeal Diseases Surveillance in South Africa (GERMS-SA) between January 2019 and December 2020. Methods. Patients of all ages with CRE bacteraemia were included and isolates, when available, were sent to the reference laboratory for confirmatory testing and molecular characterisation. Multivariable logistic regression analysis was performed to assess factors associated with in-hospital mortality. Results. We included 2 144 patients with CRE bacteraemia with a median age of 33 (interquartile range 1 - 51) years, of whom 1 145 (54.2%) were male. Klebsiella pneumoniae accounted for 79.8% of infections (n=863/1 082), of which 89.5% (n=611/683) were healthcare associated (HA). The most common carbapenemase genes were carbapenem-hydrolysing oxacillinase-48 (blaOXA-48-like) (76.8%; n=761/991), New Delhi metallo-β-lactamase (blaNDM) (21.1%; n=209/991) and Verona integron-encoded metallo-β-lactamase (blaVIM) (1.3%; n=13/991). None of the screened isolates with a colistin minimum inhibitory concentration >2 μg/mL harboured the mobilised colistin resistance (mcr)-1 to mcr-5 genes. The crude in-hospital mortality rate was 36.6% (n=377/1 029). Patients aged ≥60 years (v. 1.6 - 9 years) (adjusted odds ratio (aOR) 4.53; 95% confidence interval (CI) 2.21 - 9.28), those with comorbidities (diabetes, malignancy, renal and/or cardiovascular failure) (aOR 1.72; 95% CI 1.17 - 2.52), those with altered mental state (aOR 5.36; 95% CI 3.21 - 8.92) and those with previous antimicrobial use (aOR 1.88; 95% CI 1.27 - 2.77) had increased odds of in-hospital mortality. Conclusion. The epidemiology of CRE bloodstream infections remained similar compared with the previous surveillance report. Most infections were HA and caused by OXA-48-like carbapenemase-producing K. pneumoniae with no plasmid-mediated colistin resistance. Standard infection control measures should be strengthened

Time-dependent reduction of structural complexity of the buccal epithelial cell nuclei after treatment with silver nanoparticles

Recent studies have suggested that silver nanoparticles (AgNPs) may affect cell DNA structure in in vitro conditions. In this paper, we present the results indicating that AgNPs change nuclear complexity properties in isolated human epithelial buccal cells in a time-dependent manner. Epithelial buccal cells were plated in special tissue culture chamber / slides and were kept at 37°C in an RPMI 1640 cell culture medium supplemented with L-glutamine. The cells were treated with colloidal silver nanoparticles suspended in RPMI 1640 medium at the concentration 15 mg L−1. Digital micrographs of the cell nuclei in a sample of 30 cells were created at five different time steps: before the treatment (controls), immediately after the treatment, as well as 15 , 30 and 60 min after the treatment with AgNPs. For each nuclear structure, values of fractal dimension, lacunarity, circularity, as well as parameters of grey level co-occurrence matrix (GLCM) texture, were determined. The results indicate time-dependent reduction of structural complexity in the cell nuclei after the contact with AgNPs. These findings further suggest that AgNPs, at concentrations present in today's over-the-counter drug products, might have significant effects on the cell genetic material

Surveillance and comparison of antimicrobial susceptibility patterns of ESKAPE organisms isolated from patients with bacteraemia in South Africa, 2016 - 2017

Background. In South Africa (SA), the National Department of Health has developed an Antimicrobial Resistance National Strategy Framework document to manage antimicrobial resistance (AMR). One of the strategic objectives is to optimise surveillance and early detection of AMR. At the National Institute for Communicable Diseases (NICD), an analysis of selected organisms and antimicrobial agents from both the public and the private sectors was conducted.Objectives. The relevance of surveillance for AMR is increasingly recognised in the light of global action plans to combat resistance. In this report, we present an overview of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) organisms and Escherichia coli reported from public and private sector laboratories in SA for the period 2016 - 2017.Methods. Antimicrobial susceptibility testing (AST) profiles on selected ESKAPE organisms and E. coli isolated from blood cultures from the public and private sectors in 2016 and 2017 were analysed. AST data were extracted from a web-based electronic platform created by the NICD. Drug-bug combinations following the World Health Organization’s Global Antimicrobial Surveillance System guidelines were included in the analysis.Results. A total of 28 920 ESKAPE organisms and E. coli were reported in 2016 and 32 293 in 2017 across the two health sectors. Proportions of some organisms differed between the two health sectors, such as E. coli (19% in the public sector and 36% in the private sector), A. baumannii (14% public and 4% private), P. aeruginosa (7% public and 11% private) and S. aureus (27% public and 17% private). Susceptibility data indicated changing patterns in both sectors towards an increase in non-susceptibility to carbapenems in K. pneumoniae (p<0.01). However, we demonstrated an increase in susceptibility to cloxacillin in S. aureus (p<0.01) in both sectors.Conclusions. The key clinically important finding is the rapidly decreasing carbapenem susceptibility among Enterobacteriaceae reported in SA, irrespective of sector. In addition, the analysis provides information that could be used to monitor the effectiveness of interventions implemented at a national level under the guidance and direction of the national AMR framework.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry identification of Vibrio (Listonella) anguillarum isolated from sea bass and sea bream

Vibrio (Listonella) anguillarum is a pathogenic bacterium causing septicaemia in a wide range of marine organisms and inducing severe mortalities, thus it is crucial to conduct its accurate and rapid identification. The aim of this study was to assess MALDI-TOF MS as a method of choice for identification of clinical V. anguillarum isolates from affected marine fish. Since the method accuracy might be influenced by the type of the medium used, as well as by the incubation conditions, we tested V. anguillarum isolates grown on standard media with and without the addition of NaCl, cultured at three incubation temperatures, and at three incubation periods. The best scores were retrieved for V. anguillarum strains grown on NaCl-supplemented tryptone soy agar (TSA) at 22°C and incubated for 48h (100% identification to species level; overall score 2.232), followed by incubation at 37°C and 48h (100% to species level; score 2.192). The strains grown on non-supplemented TSA gave the best readings when incubated at 22°C for 72h (100% identification to species level; overall score 2.182), followed by incubation at 15°C for 72h (100% to species level; score 2.160). Unreliable identifications and no-identifications were growing with the incubation duration at 37°C, on both media, amounting to 88.89% for 7d incubation on supplemented TSA, and 92.60% for 7d incubation on non-supplemented TSA. The age of the cultured strains and use of media significantly impacted the mass spectra, demonstrating that for reliable identification, MALDI-TOF MS protein fingerprinting with the on-target extraction should be performed on strains grown on a NaCl-supplemented medium at temperatures between 15 and 22°C, incubated for 48-72 hours

Predicted enhanced human propensity of current avian-like H1N1 swine influenza virus from China

Influenza A virus (IAV) subtypes against which little or no pre-existing immunity exists in humans represent a serious threat to global public health. Monitoring of IAV in animal hosts is essential for early and rapid detection of potential pandemic IAV strains to prevent their spread. Recently, the increased pandemic potential of the avian-like swine H1N1 IAV A/swine/Guangdong/104/2013 has been suggested. The virus is infectious in humans and the general population seems to lack neutralizing antibodies against this virus. Here we present an in silico analysis that shows a strong human propensity of this swine virus further confirming its pandemic potential. We suggest mutations which would further enhance its human propensity. We also propose conserved antigenic determinants which could serve as a component of a prepandemic vaccine. The bioinformatics tool, which can be used to further monitor the evolution of swine influenza viruses towards a pandemic virus, are described here and are made publically available (http://www.vin.bg.ac.rs/180/tools/iav-mon.php; http://www.biomedprotection.com/iav-mon.php)