Ninfa María Rosas García

Entomopathogenic fungi produce chemical compounds that may provide different biological activities, and biotic and abiotic factors influence their production. This work aimed to determine the production of chemical compounds during the growth of the Beauveria bassiana GHA strain in nine different culture media. The media used were malt extract agar (MEA), potato dextrose agar (PDA), Spezieller Nahrstoffarmer agar (SNA), Sabouraud dextrose agar (SDA) enriched with yeast extract; yeast extract casein peptone dextrose agar (YEPDA), and potato dextrose-fungus (Agaricus bisporus) (PDF) as well as oats based medium (OBM), rice based medium (RBM), and CHEERIOS^® (Whole oats, Nestlé^®) based medium (CHBM). The GHA strain was incubated in each medium at 28 °C for 21 days. The fungal growth was measured by biomass production, and the production of chemical compounds was evaluated through a GC-MS analysis. Results indicated significant differences in biomass production among the different culture media. The highest biomass production was observed in the SDA and OBM, while no growth was observed in the PDA, MEA, and SNA media. The GC-MS analysis detected 156 compounds, including 54 extracted with methanol, 65 with ethyl acetate, and 37 with hexane. The number of compounds varied according to the media used. These chemical compounds correspond to amines, alcohols, fatty acids, and amino acids, among many others. The nutrients available in the growth media have an essential influence on the chemical compound production by B. bassiana GHA strain.

Klebsiella oxytoca has emerged as an important opportunistic pathogen in nosocomial infections, particularly during the COVID-19 pandemic, due to its capacity to acquire and disseminate resistance and virulence genes through horizontal gene transfer (HGT). This study presents a genome-based comparative analysis of K. oxytoca within the genus Klebsiella, aimed at exploring the evolutionary plausibility of outer membrane vesicle (OMV) associated processes in bacterial adaptation. Using publicly available reference genomes, we analyzed pangenome structure, phylogenetic relationships, and the distribution of mobile genetic elements, resistance determinants, virulence factors, and genes related to OMV biogenesis. Our results reveal a conserved set of envelope associated and stress responsive genes involved in vesiculogenic pathways, together with an extensive mobilome and resistome characteristic of the genus. Although these genomic features are consistent with conditions that may favor OMV production, they do not constitute direct evidence of functional OMV mediated horizontal gene transfer. Instead, our findings support a hypothesis generating evolutionary framework in which OMVs may act as a complementary mechanism to established gene transfer routes, including conjugation, integrative mobile elements, and bacteriophages. Overall, this study provides a genomic framework for future experimental and metagenomic investigations into the role of OMV-associated processes in antimicrobial resistance dissemination and should be interpreted as a recently identified evolutionary strategy inferred from genomic data, rather than a novel or experimentally validated mechanism.

The strain Bacillus inaquosorum LBA001 was isolated from a soil sample as a potential entomopathogenic bacteria; and produces a brown pigment at each growth on LB (Luria-Bertani) agar. We investigated its biochemical and physiological characteristics using the standard bacteriological technique. The whole genome sequencing was used to explore its genetic composition and metabolic capabilities. We used whole genome sequencing to examine the role of its genetic makeup and its potential metabolic capacity. The whole genome assembly resulted in one scaffold with a GC content of 43.19% and a genome size of about 4.3 Mb. The Prokka annotation showed 4,149 coding sequences and full sets of ribosomal RNA (5S, 16S, and 23S). The pan genome analysis identified 192 core genes among the strains compared with numerous accessory genes in individual strains. Phylogenetic analysis confirmed that it belongs to the B. inaquosorum clade, as it has much in common with B. inaquosorum KCTC 13249 ^T. AntiSMASH indicated that LBA001 contains certain groups of biosynthetic genes such as bacilysin, surfactin, fengycin, bacillaene, and pulcherriminic acid among others. The predicted proteome of LBA001 was subjected to BLAST-based homology searches against reference pigment gene database. The analysis identified 23 high-confidence pigment biosynthesis genes, with five different types of pigments in seven distinct colors. Numerous CAZymes in LBA00 were predicted, suggesting its potential applications in biotechnology and agriculture. The identification of potential antibiotic resistance genes in LBA001 genome reflected its adaptive characteristics. These findings will add to our understanding of B. inaquosorum metabolic versatility and its potential as a beneficial source of bioactive compounds.

In Mexico, Chloridea virescens is a pest of chickpea, tomato and other vegetables causing significant economic losses. To control this pest, three different strains (M1, M2 and M3) of Metarhizium robertsii (previously Metarhizium anisopliae ) and three strains of Beauveria bassiana (B1, B3 and B9) were evaluated under laboratory conditions, based on radial growth parameters, and conidia production and germination. The pathogenicity of the best strains was assessed at concentration of 1×10 ⁸ conidia/mL, against second and third instar larvae of C. virescens , at 28 ± 1 °C, 70 ± 5 % of relative humidity and a photoperiod of 12 hours light. The six strains caused larvae mortality of C. virescens , ranging from 57% to 97%, with statistically significant differences compared with the control ( P < 0.02). The M1 strain of M. robertsii exhibited the highest radial growth of 4.79 ± 0.02 cm, a growth rate of 3.33 mm/day, and a production of 6×10 ⁹ conidia/mL at 14 days, with 96% of germination at 24 hours. In terms of pathogenicity M1 caused 97% of total larvae mortality at 7 days with TL ₅₀ of 4 days. The M2 and M3 strains caused mortality of 83% and 77% with a TL ₅₀ of 4 days. Strains B1, B3 and B9 have mortalities of 63%, 57% and 70% with a TL ₅₀ of 4.3 days. (M1) M. robertsii had the best performance across all evaluated parameters, and it is therefore recommended for field testing to control of C. virescens .

Este es un primer estudio de Malvastrum americanum con los objetivos de identificar la planta y metabolitos y evaluar un extracto de la flor contra Spodoptera frugiperda. La muestra presento un 99.12% de similitud con M. americanum, mientras que por Cromatografía de Gases se identificó: isovanilina, ciclohexasiloxano, dodecametilo, hexadecametilo, tetradecametilo, y ácido hexadecanoico asociados con efectos medicinales, y con Espectroscopia Infrarroja por trasformada de Fourier mostro grupos O-H, C-C, C=H, C-H, relacionados con flavonoides y terpenoides asociados con efectos biológicos hacia insectos. En el bioensayo a 10 mg/ml tuvo una mortalidad de 62 % y una DL50 de 9.23 mg/ml contra larvas neonatas de S. frugiperda demostrando que M. americanum contiene sustancias bioactivas con propiedades insecticidas.

In the SARS-CoV-2 lineage, RNA elements essential for its viral life cycle, including genome replication and gene expression, have been identified. Still, the precise structures and functions of these RNA regions in coronaviruses remain poorly understood. This lack of knowledge points out the need for further research to better understand these crucial aspects of viral biology and, in time, prepare for future outbreaks. In this research, the in silico analysis of the cis RNA structures that act in the alpha-, beta-, gamma-, and deltacoronavirus genera has provided a detailed view of the presence and adaptation of the structures of these elements in coronaviruses. The results emphasize the importance of these cis elements in viral biology and their variability between different viral variants. Some coronavirus variants in some groups, depending on the cis element (stem-loop1 and -2; pseudoknot stem-loop1 and -2, and s2m), exhibited functional adaptation. Additionally, the conformation flexibility of the s2m element in the SARS variants was determined, suggesting a coevolution of this element in this viral group. The variability in secondary structures suggests genomic adaptations that may be related to replication processes, genetic regulation, as well as the specific pathogenicity of each variant. The results suggest that RNA structures in coronaviruses can adapt and evolve toward different viral variants, which has important implications for viral adaptation, pathogenicity, and future therapeutic strategies.

In this work, we studied 46 bacterial isolates to determine their potential for polyethylene terephthalate (PET) degradation. Only eight lipase-positive isolates were pre-selected to continue analysis. The isolates belonged to the genera Micrococcus, Acinetobacter, Pseudomonas, Bacillus, and Pseudochrobactrum. In addition to lipase, other enzymatic activities such as protease, carboxymethyl cellulase, xylanase, and chitinase were detected. PET sheets were pretreated with temperature, UV light, HNO₃, and Stenotrophomonas pavanii. All isolates were tested against pretreated PET for 60 days. All isolates displayed lipase activity, and some hydrolase activities. The chemical changes of PET sheets were determined using Fourier-transform infrared spectroscopy. Peaks observed at 3000-3500 cm-1 corresponding to hydroxyl group suggested degradation. The physical changes of PET observed with the naked eye and with SEM consisted of erosion, bubbles, scales, bumps, pits, and a shiny surface. Pseudomonas soli was selected as the best PET degrader, according to the notable changes in the infrared spectrum and macroscopic changes compared to the other genera and the control. In addition, this isolate did not show xylanase activity and it lacks the chitinase gene too. It is possible that not only lipase activity could be associated with the PET degradation, but also another enzymatic activity not detected in this study. Although the genus Pseudomonas has been reported as a plastic degrader, the P. soli species is novel in the degradation of PET, as well as the other genera mentioned here. Finally, these findings contribute to the knowledge of bacterial species for PET degradation.

SARS-CoV-2 was the cause of the global pandemic that caused a total of 14.9 million deaths during the years 2020 and 2021, according to the WHO. The virus presents a mutation rate between 10−5 and 10−3 substitutions per nucleotide site per cell infection (s/n/c). Due to this, studies aimed at knowing the evolution of this virus could help us to foresee (through the future development of new detection strategies and vaccines that prevent the infection of this virus in human hosts) that a pandemic caused by this virus will be generated again. In this research, we performed a functional annotation and identification of changes in Nsp (non-structural proteins) domains in the coronavirus genome. The comparison of the 13 selected coronavirus pangenomes demonstrated a total of 69 protein families and 57 functions associated with the structural domain’s differentials between genomes. A marked evolutionary conservation of non-structural proteins was observed. This allowed us to identify and classify highly pathogenic human coronaviruses into alpha, beta, gamma, and delta groups. The designed Nsp cluster provides insight into the trajectory of SARS-CoV-2, demonstrating that it continues to evolve rapidly. An evolutionary marker allows us to discriminate between phylogenetically divergent groups, viral genotypes, and variants between the alpha and betacoronavirus genera. These types of evolutionary studies provide a window of opportunity to use these Nsp as targets of viral therapies.

Recently, there is growing interest in obtaining bioactive compounds from species in the family Cactaceae, which has been little analyzed at the genomic and transcriptomic level. We here report the assembly of the genome of Cereus fernambucensis and we analyzed six cactus genomes (Carnegiea gigantea, Lophocereus schottii, Pachycereus pringlei, Pereskia humboldtii, Selenicereus undatus and Stenocereus thurberi), the annotation of putative genes, and the modeling of the three-dimensional structures of their predicted proteins involved in flavonoid metabolism. We identified genes encoding proteins related to plant pathogenesis (PR-10), coding secuences (CDS) of aldehyde reductase and flavonoid reductase, CDS of enzymes involved in the biosynthesis of phenolic compounds, and ABC transporters. The grouping of the enzymes aspartic proteinase-like protein, flavanone 3-hydroxylase (F3H), hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT), and protein serine/threonine- phosphatase was shown to be highly conserved in the genomes of the analyzed cacti. We found divergence of the plant PDR ABC-type transporter family protein (PEN3) in Cereus fernambucensis and the absence in this species of sterol methyltransferase (SMT1). Our three-dimensional modeling of the tertiary structure of F3H from a consensus sequence of cactus species had 88 % identity with that reported in Arabidopsis thaliana. We observed the conservation in several plant species of the 2-oxoglutarate and iron-dependent domain of F3H. This is the first report of an exploration of putative genes encoding enzymes involved in secondary metabolism in cacti species providing information that could be used to improve the production of bioactive compounds in them. Resumen. Recientemente, ha incrementado el interés en obtener compuestos bioactivos de especies de la familia Cactaceae, que ha sido poco analizada a nivel genómico y transcriptómico. Nosotros reportamos el ensamblaje del genoma Cereus fernambucensis y analizamos además seis genomas de cactus (Carnegiea gigantea, Lophocereus schottii, Pachycereus pringlei, Pereskia humboldtii, Selenicereus undatus y Stenocereus thurberi), la anotación de genes putativos y el modelado de las estructuras tridimensionales de sus proteínas involucradas en el metabolismo de los flavonoides. Se identificaron genes que codifican proteínas relacionadas con la patogénesis vegetal (PR-10), secuencias codificantes (CDS) de aldehído reductasas y flavonoide reductasas, CDS de enzimas implicadas en la biosíntesis de compuestos fenólicos y transportadores ABC. La agrupación de las enzimas similar a la proteinasa aspártica, flavanona 3-hidroxilasa (F3H), hidroxicinamoil-CoA shikimato/quinato hidroxicinamoiltransferasa (HCT) y proteína serina/treonina-fosfatasa demostró estar altamente conservada en los genomas de los cactus analizados. Se encontró divergencia de la proteína (PEN3) de la familia transportadora de tipo ABC PDR en Cereus fernambucensis y la ausencia en esta especie de esterol metiltransferasa (SMT1). Nuestro modelado tridimensional de la estructura terciaria de F3H a partir de una secuencia consenso de especies de cactus tuvo una identidad del 88 % con la reportada en Arabidopsis thaliana. Observamos la conservación en varias especies vegetales del dominio 2-oxoglutarato y dependiente del hierro de F3H. Este es el primer informe de una exploración de genes putativos que codifican enzimas involucradas en el metabolismo secundario en especies de cactus que aporta información que podría usarse para mejorar la producción de compuestos bioactivos.