Cold-adapted and rhizosphere-competent strain of Rahnella sp. with broad-spectrum plant growth-promotion potential

A phosphate-solubilizing bacterial strain isolated from Hippophae rhamnoides rhizosphere was identified as Rahnella sp. based on its phenotypic features and 16S rRNA gene sequence. The bacterial strain showed the growth characteristics of a cold-adapted psychrotroph, with the multiple plant growth-promoting traits of inorganic and organic phosphate solubilization, 1-aminocyclopropane-1- carboxylate-deaminase activity, ammonia generation, and siderophore production. The strain also produced indole- 3-acetic acid, indole-3-acetaldehyde, indole-3-acetamide, indole-3-acetonitrile, indole-3-lactic acid, and indole-3- pyruvic acid in tryptophan-supplemented nutrient broth. Gluconic, citric and isocitric acids were the major organic acids detected during tricalcium phosphate solubilization. A rifampicin-resistant mutant of the strain exhibited high rhizosphere competence without disturbance to the resident microbial populations in pea rhizosphere. Seed bacterization with a charcoal-based inoculum significantly increased growth in barley, chickpea, pea, and maize under the controlled environment. Microplot testing of the inoculum at two different locations in pea also showed significant increase in growth and yield. The attributes of coldtolerance, high rhizosphere competence, and broad-spectrum plant growth-promoting activity exhibited the potential of Rahnella sp. BIHB 783 for increasing agriculture productivity.     

Six years of wild bee monitoring shows changes in biodiversity within and across years and declines in abundance

Wild bees form diverse communities that pollinate plants in both native and agricultural ecosystems making them both ecologically and economically important. The growing evidence of bee declines has sparked increased interest in monitoring bee community and population dynamics using standardized methods. Here, we studied the dynamics of bee biodiversity within and across years by monitoring wild bees adjacent to four apple orchard locations in Southern Pennsylvania, USA. We collected bees using passive Blue Vane traps continuously from April to October for 6 years (2014–2019) amassing over 26,000 bees representing 144 species. We quantified total abundance, richness, diversity, composition, and phylogenetic structure. There were large seasonal changes in all measures of biodiversity with month explaining an average of 72% of the variation in our models. Changes over time were less dramatic with years explaining an average of 44% of the variation in biodiversity metrics. We found declines in all measures of biodiversity especially in the last 3 years, though additional years of sampling are needed to say if changes over time are part of a larger trend. Analyses of population dynamics over time for the 40 most abundant species indicate that about one third of species showed at least some evidence for declines in abundance. Bee family explained variation in species‐level seasonal patterns but we found no consistent family‐level patterns in declines, though bumble bees and sweat bees were groups that declined the most. Overall, our results show that season‐wide standardized sampling across multiple years can reveal nuanced patterns in bee biodiversity, phenological patterns of bees, and population trends over time of many co‐occurring species. These datasets could be used to quantify the relative effects that different aspects of environmental change have on bee communities and to help identify species of conservation concern.     

The Role of Fluoride in Montmorillonite-Catalyzed RNA Synthesis

The montmorillonite-catalyzed reactions of the 5′-phosphorimidazolide of adenosine in the presence of fluoride were investigated to complete our study on the effect of salts on this type of reaction. Both anions and cations have been found to influence the oligomerization reactions of the activated nucleotides, being used here as a model system for pre-biotic RNA synthesis. However, in total contrast to the behavior of the activated nucleotides in the presence of montmorillonite and other salts, alkali metal fluorides did not yield any detectable oligomerization products except in very dilute (<0.005 M) solutions of fluoride. Instead, 5′-phosphorofluoridates were formed. Their identity was confirmed by a combination of HPLC, mass spectrometry, synthesis, and NMR.     

Phosphocaveolin-1 is a mechanotransducer that induces caveola biogenesis via Egr1 transcriptional regulation

Maintenance of epithelial cell adhesion is crucial for epidermal morphogenesis and homeostasis and relies predominantly on the interaction of keratins with desmosomes. Although the importance of desmosomes to epidermal coherence and keratin organization is well established, the significance of keratins in desmosome organization has not been fully resolved. Here, we report that keratinocytes lacking all keratins show elevated, PKC-α–mediated desmoplakin phosphorylation and subsequent destabilization of desmosomes. We find that PKC-α activity is regulated by Rack1–keratin interaction. Without keratins, desmosomes assemble but are endocytosed at accelerated rates, rendering epithelial sheets highly susceptible to mechanical stress. Re-expression of the keratin pair K5/14, inhibition of PKC-α activity, or blocking of endocytosis reconstituted both desmosome localization at the plasma membrane and epithelial adhesion. Our findings identify a hitherto unknown mechanism by which keratins control intercellular adhesion, with potential implications for tumor invasion and keratinopathies, settings in which diminished cell adhesion facilitates tissue fragility and neoplastic growth.     

Thermal enhancement of the effectiveness of gamma radiation for induction of reproductive death in cultured mammalian cells.

The induction by gamma radiation of reproductive death in cultured cells derived from a rat ureter carcinoma (RUC-2) and from Chinese-hamster lung tissue (CH-V79) was shown to be enhanced by hyperthermic treatments at 41, 43 and 45 degrees C. The degree of enhancement was found to depend on the line of cells studied, the temperature employed and the level of damage considered. The influence of accumulating sublethal damage was decreased by hyperthermia, and the final slope of the radiation survival curve was increased. The degree of enhancement of lethal damage was found to depend on the time interval between the heat treatment and irradiation, especially at 41 degrees C.