Design and Characterization of Myristoylated and Non-Myristoylated Peptides Effective against Candida spp. Clinical Isolates

The increasing resistance of fungi to antibiotics is a severe challenge in public health, and newly effective drugs are required. Promising potential medications are lipopeptides, linear antimicrobial peptides (AMPs) conjugated to a lipid tail, usually at the N-terminus. In this paper, we investigated the in vitro and in vivo antifungal activity of three short myristoylated and non-myristoylated peptides derived from a mutant of the AMP Chionodracine. We determined their interaction with anionic and zwitterionic membrane-mimicking vesicles and their structure during this interaction. We then investigated their cytotoxic and hemolytic activity against mammalian cells. Lipidated peptides showed a broad spectrum of activity against a relevant panel of pathogen fungi belonging to Candida spp., including the multidrug-resistant C. auris. The antifungal activity was also observed vs. biofilms of C. albicans, C. tropicalis, and C. auris. Finally, a pilot efficacy study was conducted on the in vivo model consisting of Galleria mellonella larvae. Treatment with the most-promising myristoylated peptide was effective in counteracting the infection from C. auris and C. albicans and the death of the larvae. Therefore, this myristoylated peptide is a potential candidate to develop antifungal agents against human fungal pathogens.     

The Dead-Pressing Phenomenon in an ANFO Explosive

The dead-pressing phenomenon or pressure desensitization in ANFO as well as in other civil explosives is well-known. However, to our knowledge, the detailed study of this phenomenon in ANFO has not been carried out or reported. Therefore, such a study was planned in a SveDeFo research program. Blasting experiments in iron pipes were performed. Mainly, the density of dead-pressing and the transmission distance of detonation in the dead-pressed ANFO were studied. The results show that the dead-pressing density of the tested ANFO, Prillit A (a trademark of Nitro Nobel AB in Sweden), in diameters 45 mm, 60 mm and 75 mm of steel pipes is respectively 1.35, 1.39 and 1.43 [g/cm³]. The dependence of the detonation transmission distance on the density of the ANFO has also been outlined.     

Electrostatic Adsorption of a Colloidal Sintering Agent on Silicon Nitride Particles

Pressureless sintering of silicon nitride requires addition of sintering agents. The main part of this study was done in order to homogenize the distribution of sintering agents, in this case Y₂O₃, in a silicon nitride matrix. Colloidal 10-nm Y₂O₃ Particles were electrostatically adsorbed on Si₃N₄ particle surfaces. The adsorption was studied by X-ray fluorescence analysis and electrophoretic measurements. Addition of Y₂O₃ sol to a Si₃N₄ suspension decreased the viscosity of the suspension. The slip casting properties of Si₃N₄ suspensions with added Y₂O₃ sol were examined, and the homogeneity of Y₂O₃ in the green compacts was compared with conventionally prepared samples. An improved microstructural homogeneity was obtained when Y₂O₃ sol particles were adsorbed on the Si₃N₄ particle surfaces.     

Densification and Thermal Conductivity of AIN Doped with Y2O3, CaO, and Li2O

Small amounts of Li₂O result in sintering in the AIN-Y₂O₃-CaO and AIN-CaO systems at firing temperatures <1600°C. The effect is ascribed to reduction of the liquidus temperature. Furthermore, Li₂O is removed by volatization at temperatures from 1300° to 1600°C, and its content decreases several ppm from the initial 0.3 wt%. Li₂O-doped AIN specimens containing Y₂O₃ and CaO additives are well densified by firing at 1600°C for 6 h, and their thermal conductivity is 135 W^.m^−1.K⁻¹.The effect of Li₂O addition on sintering and thermal conductivity also is discussed through thermo-dynamic considerations.     

Monitoring the bacterial population dynamics during fermentation of artisanal Argentinean sausages

The dynamics of the microbial community responsible for the artisanal fermentation of dry sausage produced in Argentina was investigated by using classical and molecular approaches. The combined use of RAPD analysis with primers M13, XD9, RAPD1 and RAPD2 and 16S rDNA sequencing were applied to the identification and intraspecific differentiation of 100 strains of lactobacilli and Micrococcaceae. DGGE analysis was used to monitor the dynamic changes in population after total microbial DNA was directly extracted from sausages and subjected to PCR using V3f (GC), Bact-0124f-GC and Univ-0515r primers. The sequence analysis of 16S rDNA of the dominant species was also carried out. Lactobacillus sakei and Lactobacillus plantarum were the dominant lactic acid organisms during the fermentation while Staphylococcus saprophyticus represented the dominant species of Micrococcaceae. It was demonstrated that the ripening process of Argentinean artisanal fermented sausage is driven by a limited number of Lactobacillus and Staphylococcus strains selected from environmental microbiota by the ability to best compete under the prevailing conditions of the ecological niche. The identification of dominant communities present in this artisanal fermented sausage can help in the selection of starter cultures consisting in well adapted strains to the particular production technology.     

Lactoferrin and lysozyme in milk during acute mastitis and their inhibitory effect in Delvotest P

Microbiological methods for detection of antibiotic residues in milk give no explanations regarding the identity of the inhibitory substance(s). Natural antibacterial substances, present at higher concentrations in mastitic milk and in colostrum, occasionally cause false positive results in antibiotic assays. In an earlier investigation, lysozyme and lactoferrin were shown to inhibit the growth of Bacillus stearothermophilus var. calidolactis spores, used as test organism in Delvotest P. To study the effect of high lysozyme and lactoferrin concentrations in milk on the Delvotest P, cows were subjected to acute experimental mastitis by infusion of Salmonella typhimurium SH 4809 endotoxin. Milk samples were collected up to 11 h postinfusion. Concentrations of lactoferrin and lysozyme, somatic cell count, and effect on Delvotest P were determined. A positive reaction in the Delvotest correlated well with an increase in lactoferrin and lysozyme concentrations. The nature of the inhibitory effect is briefly discussed.     

Achieving the Sustainable Development Goals: improving water services in cities affected by extreme weather events

Abstract

This article discusses how key risks from extreme weather events might affect progress towards meeting Sustainable Development Goals 6 and 11 in cities in developing countries. It outlines the magnitude of the existing shortfall in safe water and sanitation services, and how climate change will exacerbate existing problems. It argues that the performance of many governments thus far has lacked urgency and purpose. Unless governments in particular become more committed, with redoubled effort, the goals are unlikely to be achieved.     

Crystallization of Honey at −20°C

Honeys from different regions of the province of Buenos Aires were stored at ?20°C, and factors that affect crystallization were analyzed. Crystals were observed by light microscopy. Firmness, adhesivity and viscosity of the samples were measured. Honey was characterized by determining the water activity, turbidity, moisture, fructose, and glucose contents. Results show that the viscous characteristics of the samples depend on the number, size, and disposition of crystals. Various honey samples exhibited Newtonian, pseudoplastic, and thixotropic behaviors. Crystallization was favored at higher moisture contents, suggesting that the parameters that affect honey crystallization at room temperature have a different effect at freezing temperatures. Honey that presented higher values of firmness had a moisture content lower than 17%, and a linear inverse relationship was observed between the adhesivity and firmness of honey samples.     

High quality TbMnO3 films deposited on YAlO3

High quality thin films of TbMnO₃ were grown by pulsed laser deposition on orthorhombicYAlO₃ (1 0 0). The interface and surface roughness of a 55 nm thick film were probed by X-ray reflectometry and atomic force microscopy, yielding a roughness of 1 nm. X-ray diffraction revealed untwinned films and a small mosaic spread of 0.04° and 0.2° for out-of-plane and in-plane reflections, respectively. This high degree of epitaxy was also confirmed by Rutherford backscattering spectrometry. Using polarized neutron diffraction we could identify a magnetic structure with the propagation vector (0 0.27 0), identical to the bulk magnetic structure of TbMnO₃.