Use of autonomous audio recordings for the rapid inventory of birds in the white‐sand forests of the Peruvian Amazon

White‐sand forests are patchily distributed ecosystems covering just 5% of Amazonia that host many specialist species of birds not found elsewhere, and these forests are threatened due to their small size and human exploitation of sand for construction projects. As a result, many species of birds that are white‐sand specialists are at risk of extinction, and immediate conservation action is paramount for their survival. Our objective was to evaluate current survey methods and determine the relative effect of the size of patches of these forests on the presence or absence of white‐sand specialists. Using point counts and autonomous recorders, we surveyed avian assemblages occupying patches of white‐sand forest in the Peruvian Amazon in April 2018. Overall, we detected 126 species, including 21 white‐sand forest specialists. We detected significantly more species of birds per survey point with autonomous recorders than point counts. We also found a negative relationship between avian species richness and distance from the edge of patches of white‐sand forest, but a significant, positive relationship when only counting white‐sand specialists. Although we detected more species with autonomous recorders, point counts were more effective for detecting canopy‐dwelling passerines. Therefore, we recommend that investigators conducting surveys for rare and patchily distributed species in the tropics use a mixed‐method approach that incorporates both autonomous recorders and visual observation. Finally, our results suggest that conserving large, continuous patches of white‐sand forest may increase the likelihood of survival of species of birds that are white‐sand specialists.     

What Do We Know About Metal Recycling Rates?

The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This article provides an overview on the current knowledge of recycling rates for 60 metals. We propose various recycling metrics, discuss relevant aspects of recycling processes, and present current estimates on global end‐of‐life recycling rates (EOL‐RR; i.e., the percentage of a metal in discards that is actually recycled), recycled content (RC), and old scrap ratios (OSRs; i.e., the share of old scrap in the total scrap flow). Because of increases in metal use over time and long metal in‐use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most discarded products, inherent limitations in recycling processes, and the fact that primary material is often relatively abundant and low‐cost (which thereby keeps down the price of scrap), many EOL‐RRs are very low: Only for 18 metals (silver, aluminum, gold, cobalt, chromium, copper, iron, manganese, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, tin, titanium, and zinc) is the EOL‐RR above 50% at present. Only for niobium, lead, and ruthenium is the RC above 50%, although 16 metals are in the 25% to 50% range. Thirteen metals have an OSR greater than 50%. These estimates may be used in considerations of whether recycling efficiencies can be improved; which metric could best encourage improved effectiveness in recycling; and an improved understanding of the dependence of recycling on economics, technology, and other factors.     

Collagen biosynthesis by human skin fibroblasts III. The effects of ascorbic acid on procollagen production and prolyl hydroxylase activity

Human skin fibroblasts were cultured under conditions optimized for collagen synthesis, and the effects of ascorbic acid on procollagen production, proline hydroxylation and the activity of prolyl hydroxylase were examined in cultures. The results indicated that addition of ascorbic acid to confluent monolayer cultures of adult human skin fibroblasts markedly increased tha amount of [³H]hydroxyproline syntehsized. Ascorbic acid, however, did not increase the synthesis of ³H-labeled collagenous polypeptides assayed independently of hydroxylation of proline residues, nor did it affect the amount of prolyl hydroxylase detectable by an in vitro enzyme assay. Also long-term cultures of the cells or initiation of fibroblast cultures in the presence of ascorbic acid did not lead to an apparent selection of a cell population which might be abnormally responsive to ascorbic acid. Thus, ascorbic acid appears to have one primary action on the synthesis of procollagen by cultured human skin fibroblasts: it is necessary for synthesis of hydroxyproline, and consequently for proper triple helix formation and selection of procollagen.     

Membrane targeting of RecA during genetic transformation

Recombination in prokaryotes and eukaryotes is mediated by the RecA family of proteins. Although the interactions between RecA and DNA are well studied, the cellular location of these interactions is not known. Using genetic transformation of Streptococcus pneumoniae as a model system, there was increased expression of a protein, colligrin, and RecA, products of the rec locus during genetic transfer. These proteins formed a complex and were found associated with the membranes of genetically competent cells. With immunoelectron microscopy and subcellular fractionation, we showed that the induction of competence led to the translocation of RecA and colligrin to the membrane and to the formation of clusters of RecA in a colligrin-dependent step. Based on the behaviour of colligrin and RecA during genetic exchange and the numerous proteins in prokaryotes and eukaryotes with domains similar to colligrin, we suggest that there may exist a family of proteins, which gathers macromolecules at specific sites in biological membranes.     

Profiling SARS-CoV-2 HLA-I peptidome reveals T cell epitopes from out-of-frame ORFs

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REPRODUCTIVE CAPACITY AND SEED SIZE IN LUPINUS TEXENSIS

The average number of ovules produced per individual of Lupinus texensis is much greater than the average number of seeds per plant. Each plant produces approximately 2,000 ovules but only 2.5% develop into seeds. One fourth of the seeds is lost due to abortion and 0.3% is lost due to predation on the plant. Mature seeds from this population exhibit a five-fold range in weight, from 10 to 56 mg. The distribution of seed weights in the field population is skewed and leptokurtic. Seed wt is positively correlated with both seed germination and seedling survivorship. Heritability of seed wt is 0.09. There is no correlation between average seed wt per plant and total number of seeds per plant, seeds per pod, or legumes per plant.     

Methylated poly(L-lysine): conformational effects and interactions with polynucleotides

Methylated lysine, arginine and histidine residues are found in a number of proteins (for example, histones, non-histone chromosomal proteins, ribosomal proteins, calmodulin, cytochrome C, etc.). We are studying the effects of methylation on the conformations of poly(lysine) and of the effects of methylation of poly(lysine) and poly(arginine) on interactions with polynucleotides. The conformational properties of epsilon-amino-methylated poly(lysine) differ from those of unmodified poly(lysine). Methylation increases resistance to thermally-induced and NaCl-induced changes in the CD spectrum. Guanidinium chloride increases (proportional to the degree of methylation) the extent of approach to the conformation in dispute as to its being a random coil or an extended helix. Methylation enhances aggregation in the helix-inducing solvent 0.5 M Ca(ClO4)2. With increasing methylation of poly(lysine), the conformation in dodecyl sulfate changes from beta, to 50% alpha, to random coil at the maximum methylation. Increasing methylation of poly(lysine) weakens the interaction with polynucleotides in respect to dissociation by salt, linearly with methyl content. Complexes of (dAdT)n.(dAdT)n with the polypeptides are increasingly stabilized to heat denaturation by progressive methylation. However, with a series of synthetic double-stranded RNA's and DNA's a more complex situation exists, Tm increasing or decreasing, depending on the base composition, sequence and type of sugar. Methylation of poly(lysine) and poly(arginine) can have opposite effects on Tm based on results with complexes with (dI)n.(dC)n. Methylated poly(lysine) affects the CD spectrum of polynucleotides, in a manner dependent on base composition and sequence. In some cases large positive or negative psi-spectra are induced, which, in the case of (dGdC)n.(dGdC)n, can be positive or negative depending on the degree of methylation of the polypeptide and the salt concentration. It is suggested that the biological effects of methylation proteins may be evoke by salt changes in the cell cycle, and that methylation can affect local interactions with nucleic acids and larger scale structure, and interactions with lipids.