Metabolic potential and survival strategies of microbial communities across extreme temperature gradients on Deception Island volcano,Antarctica

Active volcanoes in Antarctica have remarkable temperature and geochemical gradients that could select for a wide variety of microbial adaptive mechanisms and metabolic pathways. Deception Island is a stratovolcano flooded by the sea, resulting in contrasting ecosystems such as permanent glaciers and active fumaroles, which creates steep gradients that have been shown to affect microbial diversity. In this study, we used shotgun metagenomics and metagenome-assembled genomes to explore the metabolic potentials and survival strategies of microbial communities along an extreme temperature gradient in fumarole and glacier sediments on Deception Island. We observed that communities from a 98 °C fumarole were significantly enriched in genes related to hyperthermophilic (e.g. reverse gyrase, GroEL/GroES and thermosome) and oxidative stress responses, as well as genes related to sulfate reduction, ammonification and carbon fixation. Communities from <80 °C fumaroles possessed more genes related osmotic, cold- and heat-shock responses, and diverse metabolic potentials, such as those related to sulfur oxidation and denitrification, while glacier communities showed abundant metabolic potentials mainly related to heterotrophy. Through the reconstruction of genomes, we were able to reveal the metabolic potentials and different survival strategies of underrepresented taxonomic groups, especially those related to Nanoarchaeota, Pyrodictiaceae and thermophilic ammonia-oxidizing archaeal lineages.     

24-Epibrasinolide Delays Chlorophyll Degradation and Stimulates the Photosynthetic Machinery in Magnesium-Stressed Soybean Plants

Adverse effects caused by inadequate magnesium (Mg) supply (deficiency or excess) often cause oxidative stress in chloroplasts and a decline in photosynthetic activity. However, 24-epibrassinolide (EBR) is a natural, biodegradable, and ecologically viable plant growth regulator with multiple roles in plant metabolism. This research aims to determine whether the foliar application of EBR (1) can delay chlorophyll degradation and/or (2) mitigate oxidative stress on the photosynthetic process in magnesium-stressed soybean plants. The experiment followed a completely randomized factorial design with two concentrations of 24-epibrassinolide (0 and 0.1 mM EBR, described as – EBR and?+?EBR, respectively) and three Mg supplies (0.0225, 2.25 and 225 mM Mg, described as low, control and high supply of Mg). Inadequate Mg supplies (deficiency and excess) negatively interfered with photosynthetic pigments, chlorophyll fluorescence and gas exchange. However, exogenous EBR sprayed in plants under high Mg maximized superoxide dismutase (37%), catalase (34%), ascorbate peroxidase (48%) and peroxidase (49%), protecting against oxidative stress and delaying chlorophyll degradation. Concomitantly, plants sprayed with this steroid had increases in Mg content, improving the photochemical efficiency and gas exchange because Mg plays an essential role during the light capture process.

     

Association of TYK2 polymorphisms with autoimmune diseases: A comprehensive and updated systematic review with meta-analysis

Autoimmune diseases are characterized by the loss of self-tolerance, leading to immune-mediated tissue destruction and chronic inflammation. Tyrosine kinase 2 (TYK2) protein plays a key role in immunity and apoptosis pathways. Studies have reported associations between single nucleotide polymorphisms (SNPs) in the TYK2 gene and autoimmune diseases; however, results are still inconclusive. Thus, we conducted a systematic review followed by meta-analysis. A literature search was performed to find studies that investigated associations between TYK2 SNPs and autoimmune diseases (multiple sclerosis, systemic lupus erythematosus, Crohn’s disease, ulcerative colitis, psoriasis, rheumatoid arthritis, type 1 diabetes, and inflammatory bowel disease). Pooled odds ratios (OR) with 95 % CI were calculated using random (REM) or fixed (FEM) effects models in the Stata 11.0 Software. Thirty-four articles were eligible for inclusion in the meta-analyses, comprising 9 different SNPs: rs280496, rs280500, rs280523, rs280519, rs2304256, rs12720270, rs12720356, rs34536443, and rs35018800. Meta-analysis results showed the minor alleles of rs2304256, rs12720270, rs12720356, rs34536443, and rs35018800 SNPs were associated with protection against autoimmune diseases. Moreover, the A allele of the rs280519 SNP was associated with risk for systemic lupus erythematosus. Our meta-analyses demonstrated that the rs2304256, rs12720270, rs12720356, rs34536443, rs35018800, and rs280519 SNPs in the TYK2 gene are associated with different autoimmune diseases.     

Bioreduction of aromatic aldehydes and ketones by fruits’ barks of Passiflora edulis

A series of ketones and aldehydes were reduced using plant cell preparations from fruits’ barks of Passiflora edulis in water as solvent. The reduced products were obtained in very good yields, and low to moderate enantiomeric excesses were reached with aromatic ketones and a β-ketoester. This is the first time that the biotransformation of carbonyl compounds have been successfully achieved using Passiflora species.     

Orphan nuclear receptor COUP‐TFII enhances myofibroblast glycolysis leading to kidney fibrosis

Recent studies demonstrate that metabolic disturbance, such as augmented glycolysis, contributes to fibrosis. The molecular regulation of this metabolic perturbation in fibrosis, however, has been elusive. COUP‐TFII (also known as NR2F2) is an important regulator of glucose and lipid metabolism. Its contribution to organ fibrosis is undefined. Here, we found increased COUP‐TFII expression in myofibroblasts in human fibrotic kidneys, lungs, kidney organoids, and mouse kidneys after injury. Genetic ablation of COUP‐TFII in mice resulted in attenuation of injury‐induced kidney fibrosis. A non‐biased proteomic study revealed the suppression of fatty acid oxidation and the enhancement of glycolysis pathways in COUP‐TFII overexpressing fibroblasts. Overexpression of COUP‐TFII in fibroblasts also induced production of alpha‐smooth muscle actin (αSMA) and collagen 1. Knockout of COUP‐TFII decreased glycolysis and collagen 1 levels in fibroblasts. Chip‐qPCR revealed the binding of COUP‐TFII on the promoter of PGC1α. Overexpression of COUP‐TFII reduced the cellular level of PGC1α. Targeting COUP‐TFII serves as a novel treatment approach for mitigating fibrosis in chronic kidney disease and potentially fibrosis in other organs.     

Population dynamics of heterotrophic bacterial communities associated withFucus vesiculosus andUlva rigida in an estuary

The heterotrophic bacterial communities associated with the seaweedsFucus vesiculosus andUlva rigida in an estuary were studied. Changes in these communities were monitored by monthly sampling during the year. The isolated strains were identified at the genus level and grouped into 14 clusters by their similarities. Seasonal changes in genera and clusters as well as variations in diversity were related to primary production periods and fluctuation of salinity levels. TheFlavobacterium group was the major inhabitant of algal surfaces, being dominant after the primary production peaks occurred in spring and autumn. The decrease of dissolved organic matter after these peaks yielded an increase in diversity. Important alterations in these bacterial communities were observed during a period of large decrease in the salinity of estuarine water. In general, the epiphytic communities of both seaweeds were similar in their composition and dynamics, but they were very different from the surrounding water communities.     

Competitive dominance of antibiotic-producing marine bacteria in mixed cultures

Competitive relationships between antibiotic-producing marine bacteria and other non-producers were studied in seawater mixed cultures. Producer strains showed a competitive advantage against non-producers as the latter were inhibited after a short time. Inhibition was also noted in mixed cultures of two producer strains. The inhibitory effect was not observed in a mixed culture with two non-producers, which indicates that an amensalist interaction occurred between populations of antibiotic-producing and non-producing marine bacteria. The results suggest that antibiotics could play an important role in the competitive relationships between marine bacterial populations.     

Micropropagation of juvenile and adult Annona squamosa

A micropropagation system for Annona squamosa L. (Sugar Apple) using hypocotyls of seedlings and nodal cuttings from 3-year-old plants was developed. Shoot proliferation was achieved with Woody Plant Medium supplemented with BA. Silver thiosulphate was added at 0.5 mg l^–1 to control leaf abscission. Rooting was obtained when subcultured shoots were preconditioned for 2 weeks in medium with 10 g l^–1 activated charcoal before treatment with 43 µm NAA or 39 µm IBA. Rooting was improved when galactose was used instead of sucrose in the rooting medium. The rooted plantlets were acclimatised successfully.Abbreviations NAA naphthaleneacetic acid - IBA indolebutyric acid - MS Murashige & Skoog Medium - WPM Woody Plant Medium - NN Nitsch Medium - Juv juvenile explant - Adu adult explant