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BACKGROUND AND AIMS: Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) poses a heightened cardiovascular risk. Identifying efficient biomarkers for early MASLD detection in resource-limited Latin American regions is crucial. We aimed to evaluate the diagnostic efficacy of sixteen biomarkers for MASLD in Mexican individuals. METHODS: In this cross-sectional and analytical study, steatosis was assessed using vibration-controlled transient elastography. MASLD was defined according to international standards. Assessed biomarkers included: Visceral Fat (VF), Waist Circumference (WC), Waist-Height Ratio (WHtr), Waist-Hip Ratio (WHr), Visceral Adiposity Index (VAI), Hepatic Steatosis Index (HSI), Body Mass Index (BMI), Homeostatic Model Assessment (HOMA), Weight-Adjusted-Waist Index (WWI), Lipid Accumulation Product (LAP), Uric Acid-Creatinine Ratio (UACR), Triglyceride-Glucose Index (TyG) and its variants TyG-WC, TyG-HDL, TyG-BMI, TyG-WHtr. RESULTS: 161 participants were included, of which 122 met MASLD criteria (56 % women, age 53.9 years [47.5-64]) and 39 were healthy controls (76 % women, age 52 [45-64]). The AUROCs of the biomarkers for MASLD were: TyG-WC (0.84), LAP (0.84), TyG-BMI (0.82), TyG-WHtr (0.80), WC (0.78), TyG (0.77), WHtr (0.75), BMI (0.76), VF (0.75), HSI (0.75), TyG-HDL (0.75), WHr (0.72), VAI (0.73), UA/CR (0.70), HOMA (0.71), and WWI (0.69). Sex-based differences were observed. After adjusting for sociodemographic variables, the TyG-WC index was the best predictor of MASLD. CONCLUSIONS: In conclusion, our results underscore the potential of several noninvasive biomarkers for MASLD assessment in a Mexican population, highlighting variations in diagnostic efficacy and cut-off values between sexes. After adjusting, TyG-WC was the best MASLD predictor.

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The selection of oleaginous bacteria, potentially applicable to biotechnological approaches, is usually carried out by different expensive and time-consuming techniques. In this study, we used Oil Red O (ORO) as an useful dye for staining of neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates. ORO could detect minimal quantities of both compounds (detection limit, 0.0025 mg of tripalmitin or 0.005 mg of cetylpalmitate). In addition, we developed a specific, rapid, and inexpensive screening methodology to detect triacylglycerol-accumulating microorganisms grown on the agar plate. This staining methodology detected 9/13 strains with a triacylglycerol content higher than 20% by cellular dry weight. ORO did not stain polyhydroxyalkanoates-producing bacteria. The four oleaginous strains not detected by this screening methodology exhibited a mucoid morphology of their colonies. Apparently, an extracellular polymeric substance produced by these strains hampered the entry of the lipophilic dye into cells. The utilization of the developed screening methodology would allow selecting of oleaginous bacteria in a simpler and faster way than techniques usually used nowadays, based on unspecific staining protocols and spectrophotometric or chromatographic methods. Furthermore, the use of ORO as a staining reagent would easily characterize the neutral lipids accumulated by microorganisms as reserve compounds. KEY POINTS: • Oil Red O staining is specific for triacylglycerols • Oil Red O staining is useful to detect oleaginous bacteria • Fast and inexpensive staining to isolate oleaginous bacteria from the environment.

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In the present manuscript we present evidence of the improvement of MASLD with dietary intervention. It is known that the Mediterranean diet is the best intervention for this pathology, however, it cannot be established in all countries due to the diversity of foods. We create a Mexican diet with the nutrients of the Mediterranean diet for the treatment of our population.

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The bacterial genus Rhodococcus comprises organisms performing oleaginous behaviors under certain growth conditions and ratios of carbon and nitrogen availability. Rhodococci are outstanding producers of biofuel precursors, where lipid and glycogen metabolisms are closely related. Thus, a better understanding of rhodococcal carbon partitioning requires identifying catalytic steps redirecting sugar moieties to storage molecules. Here, we analyzed two GT4 glycosyl-transferases from Rhodococcus jostii (RjoGlgAb and RjoGlgAc) annotated as α-glucan-α-1,4-glucosyl transferases, putatively involved in glycogen synthesis. Both enzymes were produced in Escherichia coli cells, purified to homogeneity, and kinetically characterized. RjoGlgAb and RjoGlgAc presented the "canonical" glycogen synthase activity and were actives as maltose-1P synthases, although to a different extent. Then, RjoGlgAc is a homologous enzyme to the mycobacterial GlgM, with similar kinetic behavior and glucosyl-donor preference. RjoGlgAc was two orders of magnitude more efficient to glucosylate glucose-1P than glycogen, also using glucosamine-1P as a catalytically efficient aglycon. Instead, RjoGlgAb exhibited both activities with similar kinetic efficiency and preference for short-branched α-1,4-glucans. Curiously, RjoGlgAb presented a super-oligomeric conformation (higher than 15 subunits), representing a novel enzyme with a unique structure-to-function relationship. Kinetic results presented herein constitute a hint to infer on polysaccharides biosynthesis in rhodococci from an enzymological point of view.

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Strains belonging to R. opacus, R. jostii, R. fascians, R. erythropolis and R. equi exhibited differential ability to grow and produce lipids from fruit residues (grape marc and apple pomace), as well as single carbohydrates, such as glucose, gluconate, fructose and sucrose. The oleaginous species, R. opacus (strains PD630 and MR22) and R. jostii RHA1, produced higher yields of biomass (5.1-5.6 g L-1) and lipids (38-44% of CDW) from apple juice wastes, in comparison to R. erythropolis DSM43060, R. fascians F7 and R. equi ATCC6939 (4.1-4.3 g L-1 and less than 10% CDW of lipids). The production of cellular biomass and lipids were also higher in R. opacus and R. jostii (6.8-7.2 g L-1 and 33.9-36.5% of CDW of lipids) compared to R. erythropolis, R. fascians, and R. equi (3.0-3.6 g L-1 and less than 10% CDW of lipids), during cultivation of cells on wine grape waste. A genome-wide bioinformatic analysis of rhodococci indicated that oleaginous species possess a complete set of genes/proteins necessary for the efficient utilization of carbohydrates, whereas genomes from non-oleaginous rhodococcal strains lack relevant genes coding for transporters and/or enzymes for the uptake, catabolism and assimilation of carbohydrates, such as gntP, glcP, edd, eda, among others. Results of this study highlight the potential use of the oleaginous rhodococcal species to convert sugar-rich agro-industrial wastes, such as apple pomace and grape marc, into single-cell oils.

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Microorganism lipid droplet small regulator (MLDSR) is a transcriptional regulator of the major lipid droplet (LD)-associated protein MLDS in Rhodococcus jostii RHA1 and Rhodococcus opacus PD630. In this study, we investigated the role of MLDSR on lipid metabolism and triacylglycerol (TAG) accumulation in R. jostii RHA1 at physiological and molecular levels. MLDSR gene deletion promoted a significant decrease of TAG accumulation, whereas inhibition of de novo fatty acid biosynthesis by the addition of cerulenin significantly repressed the expression of the mldsr-mlds cluster under nitrogen-limiting conditions. In vitro and in vivo approaches revealed that MLDSR-DNA binding is inhibited by fatty acids and acyl-CoA residues through changes in the oligomeric or conformational state of the protein. RNAseq analysis indicated that MLDSR not only controls the expression of its own gene cluster but also of several genes involved in central, lipid, and redox metabolism, among others. We also identified putative MLDSR-binding sites on the upstream regions of genes coding for lipid catabolic enzymes and validated them by EMSA assays. Overexpression of mldsr gene under nitrogen-rich conditions promoted an increase of TAG accumulation, and further cell lysis with TAG release to the culture medium. Our results suggested that MLDSR is a fatty acid-responsive regulator that plays a dual role in cells by repression or activation of several metabolic genes in R. jostii RHA1. MLDSR seems to play an important role in the fine-tuning regulation of TAG accumulation, LD formation, and cellular lipid homeostasis, contributing to the oleaginous phenotype of R. jostii RHA1 and R. opacus PD630.

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Actinobacteria are important sources of antibiotics and have been found repeatedly in coral core microbiomes, suggesting this bacterial group plays important functional roles tied to coral survival. However, to unravel coral-actinobacteria ecological interactions and discover new antibiotics, the complex challenges that arise when isolating symbiotic actinobacteria must be overcome. Moreover, by isolating unknown actinobacteria from corals, novel biotechnological applications may be discovered. In this study, we compared actinobacteria recovery from coral samples between two widely known methods for isolating actinobacteria: dry stamping and heat shock. We found that dry stamping was at least three times better than heat shock. The assembly of isolated strains by dry stamping was unique for each species and consistent across same-species samples, highlighting that dry stamping can be reliably used to characterize coral actinobacteria communities. By analyzing the genomes of the closest related type strains, we were able to identify several functions commonly found among symbiotic organisms, such as transport and quorum sensing. This study provides a detailed methodology for isolating coral actinobacteria for ecological and biotechnological purposes.

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Despite global efforts to assess the early response and persistence of SARS-CoV-2 antibodies in patients infected with or recovered from COVID-19, our understanding of the factors affecting its dynamics remains limited. This work aimed to evaluate the early and convalescent immunity of outpatients infected with SARS-CoV-2 and to determine the factors that affect the dynamics and persistence of the IgM and IgG antibody response. Seropositivity of volunteers from Mexico City and the State of Mexico, Mexico, was evaluated by ELISA using the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein for 90 days, at different time points (1, 15, 45, 60, and 90 days) after molecular diagnosis (RT-qPCR). Gender, age range, body mass index (BMI), comorbidities, and clinical spectrum of disease were analyzed to determine associations with the dynamics of anti-SARS-CoV-2 antibodies. On 90 days post-infection, individuals with moderate and asymptomatic disease presented the lowest levels of IgM, while for IgG, at the same time, the highest levels occurred with mild and moderate disease. The IgM and IgG levels were related to the clinical spectrum of disease, BMI, and the presence/absence of comorbidities through regression trees. The results suggest that the dynamics of anti-SARS-CoV-2 IgM and IgG antibodies in outpatients could be influenced by the clinical spectrum of the disease. In addition, the persistence of antibodies against SARS-CoV-2 could be related to the clinical spectrum of the disease, BMI, and the presence/absence of comorbidities.

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In actinomycetes, the acyl-CoA carboxylases, including the so-called acetyl-CoA carboxylases (ACCs), are biotin-dependent enzymes that exhibit broad substrate specificity and diverse domain and subunit arrangements. Bioinformatic analyses of the Rhodococcus jostii RHA1 genome found that this microorganism contains a vast arrange of putative acyl-CoA carboxylases domains and subunits. From the thirteen putative carboxyltransferase domains, only the carboxyltransferase subunit RO01202 and the carboxyltransferase domain present in the multidomain protein RO04222 are highly similar to well-known essential ACC subunits from other actinobacteria. Mutant strains in each of these genes showed that none of these enzymes is essential for R. jostii growth in rich or in minimal media with high nitrogen concentration, presumably because of their partial overlapping activities. A mutant strain in the ro04222 gene showed a decrease in triacylglycerol and mycolic acids accumulation in rich and minimal medium, highlighting the relevance of this multidomain ACC in the biosynthesis of these lipids. On the other hand, RO01202, a carboxyltransferase domain of a putative ACC complex, whose biotin carboxylase and biotin carboxyl carrier protein domain were not yet identified, was found to be essential for R. jostii growth only in minimal medium with low nitrogen concentration. The results of this study have identified a new component of the TAG-accumulating machinery in the oleaginous R. jostii RHA1. While non-essential for growth and TAG biosynthesis in RHA1, the activity of RO04222 significantly contributes to lipogenesis during single-cell oil production. Furthermore, this study highlights the high functional diversity of ACCs in actinobacteria, particularly regarding their essentiality under different environmental conditions. KEY POINTS: • R. jostii possess a remarkable heterogeneity in their acyl-carboxylase complexes. • RO04222 is a multidomain acetyl-CoA carboxylase involved in lipid accumulation. • RO01202 is an essential carboxyltransferase only at low nitrogen conditions.

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The new species Amithao miradorensis Gasca-Álvarez and Deloya, is described from southern Mexico and compared to related species. Color photographs of habitus and male genitalia of the new species and related species are provided and compared. An updated taxonomic key to species in the genus in both English and Spanish is provided. Diversity and distribution of Mexican Amithao species are discussed.

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The wax ester (WE) and triacylglycerol (TAG) biosynthetic potential of marine microorganisms is poorly understood at the microbial community level. The goal of this work was to uncover the prevalence and diversity of bacteria with the potential to synthesize these neutral lipids in coastal sediments of two high latitude environments, and to characterize the gene clusters related to this process. Homolog sequences of the key enzyme, the wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT) were retrieved from 13 metagenomes, including subtidal and intertidal sediments of a Subantarctic environment (Ushuaia Bay, Argentina), and subtidal sediments of an Antarctic environment (Potter Cove, Antarctica). The abundance of WS/DGAT homolog sequences in the sediment metagenomes was 1.23 ± 0.42 times the abundance of 12 single-copy genes encoding ribosomal proteins, higher than in seawater (0.13 ± 0.31 times in 338 metagenomes). Homolog sequences were highly diverse, and were assigned to the Pseudomonadota, Actinomycetota, Bacteroidota and Acidobacteriota phyla. The genomic context of WS/DGAT homologs included sequences related to WE and TAG biosynthesis pathways, as well as to other related pathways such as fatty-acid metabolism, suggesting carbon recycling might drive the flux to neutral lipid synthesis. These results indicate the presence of abundant and taxonomically diverse bacterial populations with the potential to synthesize lipid storage compounds in marine sediments, relating this metabolic process to bacterial survival.

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Resumen El accidente cerebrovascular (ACV) constituye la principal causa de discapacidad de origen neuro- lógico en los adultos mayores a 40 años y la cuarta causa de muerte en Argentina. En los últimos diez años las publicaciones indexadas relacionadas al tratamiento del ACV isquémico fueron más numerosas que las de ACV hemorrágico. El objetivo de este material es proporcionar recomendaciones locales y actualiza- das del abordaje de pacientes con hematoma intraparenquimatoso espontáneo durante la internación. Para la redacción de este manuscrito se convocó a especialistas en esta enfermedad que conformaron grupos de trabajo. Se plantearon 10 tópicos centrales expresados como epidemiologia, atención inicial, imágenes, tratamiento de la presión arterial, reversión de antitrombóticos, indicación de cirugía, profilaxis anticonvulsivante, pronóstico, prevención de complicaciones y reinicio de antitrombóticos. De cada tópico se plantearon mediante preguntas PICO los interrogantes más frecuentes de la práctica diaria. Luego de una revisión sistemática de la literatura, se generaron recomendaciones evaluadas mediante sistema GRADE y consensuadas entre autores y pacientes.

Abstract Stroke is the leading cause of neurological disability in people over 40 years of age and the fourth leading cause of death in Argentina. In the last ten years, the indexed publications related to the treatment of ischemic stroke were more numerous than those of hemorrhagic stroke. The objective of this material is to provide local and updated recommendations for the management of patients with spontaneous intracere- bral hemorrhage during hospitalization. For the writing of this manuscript, diferent specialists were convened to form working groups. Ten central topics expressed as epidemiology, initial care, imaging, blood pressure treatment, reversal of antithrombotics, indication for surgery, seizure prophylaxis, prognosis, prevention of complications and resumption of antithrombotics were raised. For each topic, the most frequent questions of daily practice were raised through PICO questions. After a systematic review of the literature, recommendations were generated, evaluated using the GRADE system and agreed between authors and patients.

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Stroke is the leading cause of neurological disability in people over 40 years of age and the fourth leading cause of death in Argentina. In the last ten years, the indexed publications related to the treatment of ischemic stroke were more numerous than those of hemorrhagic stroke. The objective of this material is to provide local and updated recommendations for the management of patients with spontaneous intracerebral hemorrhage during hospitalization. For the writing of this manuscript, diferent specialists were convened to form working groups. Ten central topics expressed as epidemiology, initial care, imaging, blood pressure treatment, reversal of antithrombotics, indication for surgery, seizure prophylaxis, prognosis, prevention of complications and resumption of antithrombotics were raised. For each topic, the most frequent questions of daily practice were raised through PICO questions. After a systematic review of the literature, recommendations were generated, evaluated using the GRADE system and agreed between authors and patients.

El accidente cerebrovascular (ACV) constituye la principal causa de discapacidad de origen neurológico en los adultos mayores a 40 años y la cuarta causa de muerte en Argentina. En los últimos diez años las publicaciones indexadas relacionadas al tratamiento del ACV isquémico fueron más numerosas que las de ACV hemorrágico. El objetivo de este material es proporcionar recomendaciones locales y actualizadas del abordaje de pacientes con hematoma intraparenquimatoso espontáneo durante la internación. Para la redacción de este manuscrito se convocó a especialistas en esta enfermedad que conformaron grupos de trabajo. Se plantearon 10 tópicos centrales expresados como epidemiologia, atención inicial, imágenes, tratamiento de la presión arterial, reversión de antitrombóticos, indicación de cirugía, profilaxis anticonvulsivante, pronóstico, prevención de complicaciones y reinicio de antitrombóticos. De cada tópico se plantearon mediante preguntas PICO los interrogantes más frecuentes de la práctica diaria. Luego de una revisión sistemática de la literatura, se generaron recomendaciones evaluadas mediante sistema GRADE y consensuadas entre autores y pacientes.

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To ensure food security given the current scenario of climate change and the accompanying ecological repercussions, it is essential to search for new technologies and tools for agricultural production. Microorganism-based biostimulants are recognized as sustainable alternatives to traditional agrochemicals to enhance and protect agricultural production. Marine actinobacteria are a well-known source of novel compounds for biotechnological uses. In addition, former studies have suggested that coral symbiont actinobacteria may support co-symbiotic photosynthetic growth and tolerance and increase the probability of corals surviving abiotic stress. We have previously shown that this activity may also hold in terrestrial plants, at least for the actinobacteria Salinispora arenicola during induced heterologous symbiosis with a wild Solanaceae plant Nicotiana attenuata under in vitro conditions. Here, we further explore the heterologous symbiotic association, germination, growth promotion, and stress relieving activity of S. arenicola in tomato plants under agricultural conditions and dig into the possible associated mechanisms. Tomato plants were grown under normal and saline conditions, and germination, bacteria-root system interactions, plant growth, photosynthetic performance, and the expression of salt stress response genes were analyzed. We found an endophytic interaction between S. arenicola and tomato plants, which promotes germination and shoot and root growth under saline or non-saline conditions. Accordingly, photosynthetic and respective photoprotective performance was enhanced in line with the induced increase in photosynthetic pigments. This was further supported by the overexpression of thermal energy dissipation, which fine-tunes energy use efficiency and may prevent the formation of reactive oxygen species in the chloroplast. Furthermore, gene expression analyses suggested that a selective transport channel gene, SlHKT1,2, induced by S. arenicola may assist in relieving salt stress in tomato plants. The fine regulation of photosynthetic and photoprotective responses, as well as the inhibition of the formation of ROS molecules, seems to be related to the induced down-regulation of other salt stress response genes, such as SlDR1A-related genes or SlAOX1b. Our results demonstrate that the marine microbial symbiont S. arenicola establishes heterologous symbiosis in crop plants, promotes growth, and confers saline stress tolerance. Thus, these results open opportunities to further explore the vast array of marine microbes to enhance crop tolerance and food production under the current climate change scenario.

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Resumen En la Amazonía colombiana, los insectos constituyen un recurso natural abundante, el cual es aprovechado mediante el consumo de especies comestibles. Históricamente, los pueblos indígenas son entomofágicos y han incluido a insectos y otros artrópodos en sus dietas. En el presente estudio, se analiza el uso tradicional de insectos comestibles en las comunidades del oriente amazónico de Colombia. Durante el período de agosto 2020 a marzo 2021, se realizaron entrevistas abiertas y semi-estructuradas a habitantes del municipio de Mitú (Vaupés) y de 41 comunidades indígenas aledañas, las cuales indagaron sobre la percepción, aprovechamiento y comercialización de insectos comestibles. De acuerdo con su valor de uso, Rhynchophorus palmarum (Coleoptera: Curculionidae), Syntermes spinosus (Blattodea: Termitidae), Atta laevigata (Hymenoptera: Formicidae), Lusura chera (Lepidoptera: Notodontidae) y Polybia liliacea (Hymenoptera: Vespidae), constituyen las especies de insectos comestibles más representativas de la región. Para cada especie se estableció su calendario ecológico y se documentaron sus técnicas y métodos de recolecta, sus formas tradicionales de preparación y consumo, y sus actividades de comercialización. Se resalta el potencial de las especies de insectos comestibles analizadas para el fortalecimiento de estrategias de uso sostenible direccionadas a mejorar la seguridad alimentaria de la población y el mantenimiento de los conocimientos tradicionales de las comunidades.

Abstract In the Colombian Amazon, insects are an abundant natural resource, and part of the use of this resource is the consumption of some edible species. Historically, indigenous peoples are entomophagic and have included insects and other arthropods in their diets. In this paper, the traditional use of edible insects in the communities of the eastern Amazon of Colombia is analyzed. During August 2020 to March 2021, opened and semi-structured interviews carried out with inhabitants of the municipality of Mitú (Vaupés) and 41 surrounding indigenous communities were applied, inquiring about the perception, use and commercialization of edible insects. According to its use value, Rhynchophorus palmarum (Coleoptera: Curculionidae), Syntermes spinosus (Blattodea: Termitidae), Atta laevigata (Hymenoptera: Formicidae), Lusura chera (Lepidoptera: Notodontidae), and Polybia liliacea (Hymenoptera: Vespidae), are the most representative species of edible insects in the region. For each species, its ecological calendar was established, and its collecting techniques and methods, traditional forms of preparation and consumption, and marketing activities were documented. The potential of the edible insect species documented is highlighted to promote sustainable use strategies, with the aim of improving the food security of the population and maintaining the traditional knowledge of these communities.

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Metabolic syndrome (MetS) is a complex disease that affects almost a quarter of the world's adult population. In MetS, diabetes, obesity, hyperglycemia, high cholesterol, and high blood pressure are the most common disorders. Polypharmacy is the most used strategy for managing conditions related to MetS, but it has drawbacks such as low medication adherence. Multitarget ligands have been proposed as an interesting approach to developing drugs to treat complex diseases. However, suitable preclinical models that allow their evaluation in a context closer to a clinical situation of a complex disease are needed. From molecular docking studies, compound 1b, a 5-aminoanthranilic acid derivative substituted with 4'-trifluoromethylbenzylamino and 3',4'-dimethoxybenzamide moieties, was identified as a potential multitarget drug, as it showed high in silico affinity against targets related to MetS, including PPAR-α, PPAR-γ, and HMG-CoA reductase. It was evaluated in a diet-induced MetS rat model and simultaneously lowered blood pressure, glucose, total cholesterol, and triglyceride levels after a 14-day treatment. No toxicity events were observed during an acute lethal dose evaluation test at 1500 mg/kg. Hence, the diet-induced MetS model is suitable for evaluating treatments for MetS, and compound 1b is an attractive starting point for developing multitarget drugs.

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Bacis nigropictus Crotch, 1876 and Phricobacis flavomaculatus Mader, 1943 are redescribed. Redescriptions are provided with illustrations of diagnostic characters. Based upon the study of type material, Zonarius limbatus Kuhnt, 1910 is considered a new synonym of B. nigropictus. A lectotype is designated for Zonarius limbatus Kuhnt, 1910. Based on character analyses, Phricobacis flavomaculatus is here transferred to the genus Oligocorynus Dejean, 1836, becoming Oligocorynus flavomaculatus (Mader), new combination. Bacis nigropictus is newly listed for Colombia and O. flavomaculatus is considered new country record from Colombia.

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The worldwide use of plant biostimulants (PBs) represents an environmentally friendly tool to increase crop yield and productivity. PBs include different substances, compounds, and growth-promoting microorganism formulations, such as those derived from arbuscular mycorrhizal fungi (AMF) or seaweed extracts (SEs), which are used to regulate or enhance physiological processes in plants. This study analyzed the physiological, ecological, and biochemical implications of the addition of two PBs, AMF or SE (both alone and in combination), on tomato plants (Solanum lycopersicum L. cv. "Rio Fuego"). The physiological responses evaluated were related to plant growth and photosynthetic performance. The ecological benefits were assessed based on the success of AMF colonization, flowering, resistance capacity, nonphotochemical quenching (NPQ), and polyphenol content. Biochemical effects were evaluated via protein, lipid, carbohydrate, nitrogen, and phosphorous content. Each PB was found to benefit tomato plants in a different but complementary manner. AMF resulted in an energetically expensive (high ETRMAX but low growth) but protective (high NPQ and polyphenol content) response. AMF + nutritive solution (NS) induced early floration but resulted in low protein, carbohydrate, and lipid content. Both AMF and AMF + NS favored foliar instead of root development. In contrast, SE and SE + NS favored protein content and root development and did not promote flowering. However, the combination of both PBs (AMF + SE) resulted in an additive effect, reflected in an increase in both foliar and root growth as well as protein and carbohydrate content. Moreover, a synergistic effect was also found, which was expressed in accelerated flowering and AMF colonization. We present evidence of benefits to plant performance (additive and synergistic) due to the interactive effects between microbial (AMF) and nonmicrobial (SEs) PBs and propose that the complementary modes of action of both PBs may be responsible for the observed positive effects due to the new and emerging properties of their components instead of exclusively being the result of known constituents. These results will be an important contribution to biostimulant research and to the development of a second generation of PBs in which combined and complementary mechanisms may be functionally designed.

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Glycogen was described as a temporal storage molecule in rhodococci, interconnecting lipids and carbon availability. The Rhodococcus jostii ADP-glucose pyrophosphorylase (ADP-GlcPPase) kinetic and regulatory properties support this role. Curiously, the enzyme uses glucosamine-1P as alternative substrate. Herein, we report the in-depth study of glucosamine-1P activity and its regulation in two rhodocoocal ADP-GlcPPases, finding that glucosamine-6P (representing a metabolic carbon/nitrogen node) is a critical activator, then reinforcing the role of glycogen as an "intermediary metabolite" in rhodococci. Glucosamine-1P activity in rhodococcal ADP-GlcPPases responds to activation by metabolites improving their catalytic performance, strongly suggesting its metabolic feasibility. This work supports a scenario for new molecules/metabolites discovery and hypothesizes on evolutionary mechanisms underlying enzyme promiscuity opening novel metabolic features in (actino)bacteria.

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From their chemical nature to their ecological interactions, coral reef ecosystems have a lot in common with highly productive terrestrial ecosystems. While plants are responsible for primary production in the terrestrial sphere, the photosynthetic endosymbionts of corals are the key producers in reef communities. As in plants, coral microbiota have been suggested to stimulate the growth and physiological performance of the photosynthetic endosymbionts that provide energy sources to the coral. Among them, actinobacteria are some of the most probable candidates. To explore the potential of coral actinobacteria as plant biostimulants, we have analyzed the activity of Salinispora strains isolated from the corals Porites lobata and Porites panamensis, which were identified as Salinispora arenicola by 16S rRNA sequencing. We evaluated the effects of this microorganism on the germination, plant growth, and photosynthetic response of wild tobacco (Nicotiana attenuata) under a saline regime. We identified protective activity of this actinobacteria on seed germination and photosynthetic performance under natural light conditions. Further insights into the possible mechanism showed an endophytic-like symbiosis between N. attenuata roots and S. arenicola and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity by S. arenicola. We discuss these findings in the context of relevant ecological and physiological responses and biotechnological potential. Overall, our results will contribute to the development of novel biotechnologies to cope with plant growth under saline stress. Our study highlights the importance of understanding marine ecological interactions for the development of novel, strategic, and sustainable agricultural solutions.