Galectin‐9 levels have been reported to be altered in several cancer types, but the mechanism that regulates the expression of Galectin‐9 has not been clarified. Galectin‐9 is encoded by the LGALS9 gene, which gives rise to eight mRNA variants. The aims of this study were: (a) to identify the mRNA variants of LGALS9, (b) to characterize CpG methylation and H3K9 and H3K14 histone acetylation at the promoter of the LGALS9 gene, and (c) to characterize the relationship between these modifications and LGALS9 expression level in cervical cancer cells. All mRNA variants were detected in HaCaT (nontumoural keratinocytes) and SiHa cells, and seven were observed in HeLa cells. The promoter region of LGALS9 contains eight CpG dinucleotides. No hypermethylation pattern related to low LGALS9 expression was identified in tumour cells. Chromatin immunoprecipitation analysis demonstrated higher acetylation of H3K9ac and H3K14ac in HaCaT cells, which was related to higher mRNA levels. The presence of the mRNA variants suggests that alternative splicing may regulate the expression of galectin‐9 isoforms. The results of this study suggest that histone acetylation, but not promoter CpG methylation, may be involved in the transcriptional regulation of the LGALS9 gene.

The genus Quercus (Fagaceae) is one of the most widely distributed and species-diverse trees in the Northern Hemisphere. The present study addresses the investigation of the phyto-chemical profile by ten assays, the antioxidant activity scavenging of DPPH radicals, total phenolic content, total flavonoids, and antimicrobial activity against three pathogenic bacteria with the foliage of two species of red oak (Quercus sartorii and Quercus rysophylla). Both species of oak showed a high phenolic content in the aqueous extract (22,342.10 ± 3076.5 mg GAE/kg of plant and 17,747.14 ± 1139.9 mg GAE/kg of plant, respectively). In the flavonoid content, Q. sartorii showed a higher amount in the ethanolic extract (24,587.42 ± 996.3 mg QE/kg of plant), while for Q. rysophylla, it was methanolic extract (19,875.66 ± 2754.01 QE/kg of plant). In the DPPH radical scavenging activity, Q. sartorii showed the highest percentage of inhibition in the methanolic extract (81.14 ± 1.7%), while in Q. rysophylla, it was the ethanolic extract (82.60 ± 2.7%). In the antimicrobial tests, inhibition halos were obtained in the strains Acinetobacter baumannii and Staphylococcus aureus of both species. All this gives a guideline to comprehensively elucidate the metabolites present in these two species for further study and application in the dispute against pathogenic bacteria or in diseases related to the imbalance of reactive oxygen species (ROS).

Aldehyde dehydrogenases (ALDHs) are indispensable enzymes that play a pivotal role in mitigating aldehyde toxicity by converting them into less reactive compounds. Despite the availability of fully sequenced Azospirillum genomes in public databases, a comprehensive analysis of the ALDH superfamily within these genomes has yet to be undertaken. This study presents the identification and classification of 17 families and 31 subfamilies of ALDHs in fully assembled Azospirillum genomes. This classification system framework provides a more comprehensive understanding of the diversity and redundancy of ALDHs across bacterial genomes, which can aid in elucidating the distinct characteristics and functions of each family. The study also proposes the adoption of the ALDH19 family as a powerful phylogenetic marker due to its remarkable conservation and non-redundancy across various Azospirillum species. The diversity of ALDHs among different strains of Azospirillum can influence their adaptation and survival under various environmental conditions. The findings of this study could potentially be used to improve agricultural production by enhancing the growth and productivity of crops. Azospirillum bacteria establish a mutualistic relationship with plants and can promote plant growth by producing phytohormones such as indole-3-acetic acid (IAA). The diversity of ALDHs in Azospirillum can affect their ability to produce IAA and other beneficial compounds that promote plant growth and can be used as biofertilizers to enhance agricultural productivity.

Azospirillum brasilense is a PGPR that produces the phytohormone IAA, a signaling molecule involved in bacteria-plant interaction processes. IAA biosynthesis in Azospirillum is mainly carried out via the IPyA pathway in which the enzyme phenylpyruvate decarboxylase encoded by the ipdC gene is the main. The promoter region of ipdC gene contains cis elements that are highly conserved among different Azospirillum strains. In this work, we identified two proteins that interact with the promoter region of the ipdC gene, named MibR and LibR that belong to the MarR and LuxR transcriptional regulators family, respectively. Both proteins have an HTH domain, and in the case of LibR, it has a REC domain, with aspartic acid residue conserved in positions 7, 8 and 54, this last as a possible phosphorylation target. To explore their participation in the regulation of the ipdC gene, mutants of libR, mibR, and libR-mibR double mutant were generated. The results showed a decrease in IAA biosynthesis that was related to the observed decrease in ipdC gene expression mostly in the doble mutant compared with the wild type. In this work we suggest that ipdC transcription is regulated by LibR and MibR, providing new findings insight into the mechanism employed by A. brasilense to control IAA biosynthesis.

Cysteine biosynthesis is a critical metabolic pathway for bacterial physiology. However, the full impact on the lifestyle of the plant-beneficial bacterium Azospirillum brasilense Sp7 is not completely understood. Our previous work identified a cysteine synthase A (CysK-A) as a key enzyme in cysteine synthesis in A. brasilense Sp7, but its inactivation did not lead to cysteine auxotrophy, suggesting functional redundancy in this type of enzyme. Here, we comprehensively characterized an A. brasilense AR cysK-A mutant, revealing a multifaceted phenotype that highlights the indispensable role of CysK-A. The cysK-A mutant exhibited a growth defect that was rescued by genetic and chemical complementation, underscoring the importance of de novo cysteine synthesis for optimal metabolic fitness. Furthermore, the cysK-A mutant displayed a striking hyper-aggregative behavior, characterized by significantly enhanced flocculation, biofilm formation, and exopolysaccharide production. Confocal microscopy revealed an abundance of ovoid, cyst-like cells. This transition toward a sessile lifestyle, induced by cysteine limitation stress, correlated with the intracellular accumulation of cyclic-di-GMP, as determined by a c-di-GMP biosensor assay. Additionally, the cysK-A mutant exhibited increased sensitivity to exogenous hydrogen peroxide stress, a deficiency that was restored by cysK-A complementation. The mutation also led to enhanced adhesion to radish seeds; however, it did not result in statistically significant differences in overall radish seedling colonization after seven days, possibly due to compensatory mechanisms. Collectively, our findings establish CysK-A as crucial for optimal growth, stress tolerance, and the regulation of aggregative behaviors in A. brasilense Sp7, providing insights into the adaptive strategies employed by this important plant-associating bacterium.