Viability time of sporulated oocysts of bovine Eimeria spp. in water and efficacy of disinfectants in a region with tropical climate.

The water can be a significant risk factor for the occurrence of cattle eimeriosis on farms located in tropical climate regions. This study aimed to assess the viability period of sporulated oocysts of bovine Eimeria spp. in water containing organic matter and to evaluate the efficacy of disinfectants against sporulated oocysts of this protozoa. Two experiments were conducted, each comprising in vitro and in vivo evaluations. In Experiment 1, the viability period of oocysts sporulated in buckets containing a solution composed of a mixture of feces with oocysts, water, and potassium dichromate was assessed. Quantifications and identification of Eimeria spp. oocysts were performed on days + 30, + 60, + 90, and every 30 days thereafter until no more oocysts were detected. Naïve calves were inoculated with this solution kept in the bucket for 6 and 12 months. In Experiment 2, the efficacy of various disinfectants (acetic acid, sodium hypochlorite, ethanol + acetic acid, and ammonia quaternary) against a new solution of sporulated oocysts and pH changes over time (10', 30', and 24 h) were evaluated in the laboratory. The most effective disinfectant was used to treat the water solution and inoculate the calves, and its efficacy was calculated. In Experiment 1, Eimeria spp. oocysts remained viable in the solution for up to 12 months. E. zuernii persisted until the end of the study period. Calves inoculated with the solution kept in the buckets for 6 and 12 months excreted at least four Eimeria species (E. zuernii, E. bovis, E. ellipsoidalis, and E. cylindrica). In Experiment 2, among the tested disinfectants, 3% acetic acid demonstrated the highest efficacy (10' = 80.9%; 30' = 87.9%; 24 h = 91.7%). The pH values of the solutions containing acetic acid ranged from 2.4 to 3.5. Calves that received the inoculum treated with 3% acetic acid did not excrete Eimeria spp. oocysts in feces during the study period (efficacy = 100%). In contrast, all animals in the control group excreted Eimeria spp. oocysts in feces. Future studies should be carried out to better understand the possible effects of cattle drinking water with 3% acetic acid.

Implications of Domestication in Theobroma cacao L. Seed-Borne Microbial Endophytes Diversity.

The study of plant-microbe interactions is a rapidly growing research field, with increasing attention to the role of seed-borne microbial endophytes in protecting the plant during its development from abiotic and biotic stresses. Recent evidence suggests that seed microbiota is crucial in establishing the plant microbial community, affecting its composition and structure, and influencing plant physiology and ecology. For Theobroma cacao L., the diversity and composition of vertically transmitted microbes have yet to be addressed in detail. We explored the composition and diversity of seed-borne endophytes in cacao pods of commercial genotypes (ICS95, IMC67), recently liberated genotypes from AGROSAVIA (TCS01, TCS19), and landraces from Tumaco (Colombia) (AC9, ROS1, ROS2), to evaluate microbial vertical transmission and establishment in various tissues during plant development. We observed a higher abundance of Pseudomonas and Pantoea genera in the landraces and AGROSAVIA genotypes, while the commercial genotypes presented a higher number of bacteria species but in low abundance. In addition, all the genotypes and plant tissues showed a high percentage of fungi of the genus Penicillium. These results indicate that domestication in cacao has increased bacterial endophyte diversity but has reduced their abundance. We isolated some of these seed-borne endophytes to evaluate their potential as growth promoters and found that Bacillus, Pantoea, and Pseudomonas strains presented high production of indole acetic acid and ACC deaminase activity. Our results suggest that cacao domestication could lead to the loss of essential bacteria for seedling establishment and development. This study improves our understanding of the relationship and interaction between perennial plants and seed-borne microbiota.

Using cocrystals as a tool to study non-crystallizing molecules: crystal structure, Hirshfeld surface analysis and computational study of the 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine and acetic acid.

Using a 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π-π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π-π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π-π interactions without necessitating full halogenation of the aromatic ring.

Exploring the Antimicrobial Efficacy of Low-Cost Commercial Disinfectants Utilized in the Agro-Food Industry Wash Tanks: Towards Enhanced Hygiene Practices.

The increase in vegetable consumption has underlined the importance of minimizing the risks associated with microbiological contamination of fresh produce. The critical stage of the vegetable washing process has proven to be a key point for cross-contamination and the persistence of pathogens. In this context, the agri-food industry has widely adopted the use of disinfectants to reduce the bacterial load in the wash water. Therefore, we conducted laboratory-scale experiments in order to demonstrate the antimicrobial activity of disinfectants used in the wash tank of agro-food industries. Different wash water matrices of shredded lettuce, shredded cabbage, diced onion, and baby spinach were treated with sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and per-oxyacetic acid (PAA) at recommended concentrations. To simulate the presence of pathogenic bacteria, a cocktail of E. coli O157:H7 was inoculated into the process water samples (PWW) to determine whether concentrations of disinfectants inhibit the pathogen or bring it to a viable non-culturable state (VBNC). Hereby, we used quantitative qPCR combined with different photo-reactive dyes such as ethidium monoazide (EMA) and propidium monoazide (PMA). The results indicated that concentrations superior to 20 ppm NaClO inhibit the pathogen E. coli O157:H7 artificially inoculated in the process water. Concentrations between 10-20 ppm ClO2 fail to induce the pathogen to the VBNC state. At concentrations of 80 ppm PAA, levels of culturable bacteria and VBNC of E. coli O157:H7 were detected in all PWWs regardless of the matrix. Subsequently, this indicates that the recommended concentrations of ClO2 and PAA for use in the fresh produce industry wash tank do not inhibit the levels of E. coli O157:H7 present in the wash water.

Estamaran date vinegar: chemical and microbial dynamics during fermentation.

Vinegar is a fermented food produced by alcoholic and then acetic acid microbial metabolism. Date palm fruit (Phoenix dactylifera L.) is a valuable source for the production of vinegar. Microbial identification has a major role in the improvement and bio-management of the fermentation process of vinegar. Estamaran and Kabkab two varieties of date palm fruit were selected to study the fermentation process. A culture-dependent approach was used to study bacterial dynamics. 16 S rRNA gene was amplified by Polymerase Chain Reaction (PCR), also restriction enzyme analysis with HinfI and TaqI, and sequencing was done. Assessment of microbial flora of date palm fruit during fermentation showed that Fructobacillus tropaeoli, Bacillus sp., Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, and Weissella paramesenteroides existed in the first phase of fermentation. With fermentation progress, microbial diversity decreased so only one species remained. Komagataeibacter xylinus as an acid acetic producer was present in the third phase of fermentation. Based on chemical analysis, the concentration of reducing sugars decreased during fermentation. With decreasing pH, a simultaneous increase in acidity and total phenolic compounds occurred. The trend of changes during Estamaran fermentation was more severe and a vinegar with desirable properties was produced. Therefore, this date variety is recommended for the production of date vinegar.

Relationship between microstructure formation and in vitro starch digestibility in baked gluten-starch matrices.

Increased prevalence of diabetes prompts the development of foods with reduced starch digestibility. This study analyzed the impact of adding soluble dietary fiber (inulin-IN; polydextrose-PD) to baked gluten-starch matrices (7.5-13%) on microstructure formation and in vitro starch digestibility. IN and PD enhanced water-holding capacity, the hardness of baked matrices, and lowered water activity in the formulated matrices, potentially explaining the reduced starch gelatinization degree as IN or PD concentration increased. A maximum gelatinization decrease (26%) occurred in formulations with 13% IN. Micro-CT analysis showed a reduction in total and open porosity, which, along with the lower gelatinization degree, may account for the reduced in vitro starch digestibility. Samples with 13% IN exhibited a significantly lower rapidly available glucose fraction (8.56 g/100 g) and higher unavailable glucose fraction (87.76 g/100 g) compared to the control (34.85 g/100 g and 47.59 g/100 g, respectively). These findings suggest the potential for developing healthier, starch-rich baked foods with a reduced glycemic impact.

Cobalt Oxide on Boron-Doped Graphitic Carbon Nitride as Bifunctional Photocatalysts for CO2 Reduction and Hydrogen Evolution.

In this work, the prepared cobalt oxide decorated boron-doped g-C3N4 (CoOx/g-C3N4) heterojunction exhibits remarkable activity in CO2 reduction (CO2RR), resulting in high yields of CH3COOH (∼383 µmol·gcatalyst-1) and CH3OH (∼371 µmol·gcatalyst-1) with 58% selectivity to C2+ under visible light. However, the same system leads to high H2 evolution (HER) by increasing the cobalt oxide content, suggesting that the selectivity and preference for the CO2RR or HER depend on oxide decoration. By comparing HER and CO2RR evolution in the same system, this work provides critical insights into the catalytic mechanism, indicating that the CoOx/g-C3N4 heterojunction formation is necessary to foster high visible light photoactivity.

Metabolic and physiological adaptations of microalgal growth-promoting bacterium Azospirillum brasilense growing under biogas atmosphere: a microarray-based transcriptome analysis.

Using microalgal growth-promoting bacteria (MGPB) to improve the cultured microalga metabolism during biotechnological processes is one of the most promising strategies to enhance their benefits. Nonetheless, the culture condition effect used during the biotechnological process on MGPB growth and metabolism is key to ensure the expected positive bacterium growth and metabolism of microalgae. In this sense, the present research study investigated the effect of the synthetic biogas atmosphere (75% CH4-25% CO2) on metabolic and physiological adaptations of the MGPB Azospirillum brasilense by a microarray-based transcriptome approach. A total of 394 A. brasilense differentially expressed genes (DEGs) were found: 201 DEGs (34 upregulated and 167 downregulated) at 24 h and 193 DEGs (140 upregulated and 53 downregulated) under the same conditions at 72 h. The results showed a series of A. brasilense genes regulating processes that could be essential for its adaptation to the early stressful condition generated by biogas. Evidence of energy production is shown by nitrate/nitrite reduction and activation of the hypothetical first steps of hydrogenotrophic methanogenesis; signal molecule modulation is observed: indole-3-acetic acid (IAA), riboflavin, and vitamin B6, activation of Type VI secretion system responding to IAA exposure, as well as polyhydroxybutyrate (PHB) biosynthesis and accumulation. Moreover, an overexpression of ipdC, ribB, and phaC genes, encoding the key enzymes for the production of the signal molecule IAA, vitamin riboflavin, and PHB production of 2, 1.5 and 11 folds, respectively, was observed at the first 24 h of incubation under biogas atmosphere Overall, the ability of A. brasilense to metabolically adapt to a biogas atmosphere is demonstrated, which allows its implementation for generating biogas with high calorific values and the use of renewable energies through microalga biotechnologies.

Plant-specific environmental and developmental signals regulate the mismatch repair protein MSH6 in Arabidopsis thaliana.

The DNA mismatch repair (MMR) is a postreplicative system that guarantees genomic stability by correcting mispaired and unpaired nucleotides. In eukaryotic nuclei, MMR is initiated by the binding of heterodimeric MutS homologue (MSH) complexes to the DNA error or lesion. Among these proteins, MSH2-MSH6 is the most abundant heterodimer. Even though the MMR mechanism and proteins are highly conserved throughout evolution, physiological differences between species can lead to different regulatory features. Here, we investigated how light, sugar, and/or hormones modulate Arabidopsis thaliana MSH6 expression pattern. We first characterized the promoter region of MSH6. Phylogenetic shadowing revealed three highly conserved regions. These regions were analyzed by the generation of deletion constructs of the MSH6 full-length promoter fused to the ß-glucuronidase (GUS) gene. Combined, our in silico and genetic analyses revealed that a 121-bp promoter fragment was necessary for MSH6 expression and contained potential cis-acting elements involved in light- and hormone-responsive gene expression. Accordingly, light exposure or sugar treatment of four-day old A. thaliana seedlings triggered an upregulation of MSH6 in shoot and root apical meristems. Appropriately, MSH6 was also induced by the stem cell inducer WUSCHEL. Further, the stimulatory effect of light was dependent on the presence of phyA. In addition, treatment of seedlings with auxin or cytokinin also caused an upregulation of MSH6 under darkness. Consistent with auxin signals, MSH6 expression was suppressed in the GATA23 RNAi line compared with the wild type. Our results provide evidence that endogenous factors and environmental signals controlling plant growth and development regulate the MSH6 protein in A. thaliana.

Multi-trait efficiency and interactivity of bacterial consortia used to enhance plant performance under water stress conditions.

Water stress is a major limiting factor for agricultural production under current and projected climate change scenarios. As a sustainable strategy, plant growth-promoting bacterial consortia have been used to reduce plant water stress. However, few studies have examined the effects of stress on multi-trait efficiency and interactivity of bacterial species. In this study, we used several in-vitro experiments, plant assays and greenhouse trials to investigate the effects of stress and bacterial consortia on 1-aminocyclopropane-1-carboxylic acid deaminase (ACCD) activities, indole-3-acetic acid (IAA) production and plant growth-promoting traits (Phosphate-solubilization, starch hydrolysis, siderophores and ammonium production). We further assessed biofilm formation and the chemotactic behaviour in response to ACC. A total of fifteen ACCD rhizobacteria with multiple growth-promoting traits from the dominant plant species from the hyperseasonal Aripo Savannas were screened in this study. Five of the isolates were further analyzed based on their ACCD activities and were tested in single and dual consortium to assess their abilities in promoting growth under simulated drought stress (-0.35 MPa) and chemically induced ACC conditions (0.03 mM). Our findings showed that bacteria which produce high concentrations of IAA affected the isolates' ability to promote growth under stress, irrespective of microbial combination with ACCD activity above the minimal threshold of 20 nmol α-ketobutyrate mg-1 h-1. Biofilm production with co-culture interaction varied greatly across treatments, however, the general trend showed an increase in biofilm under stress induce conditions. The best performing co-culture, UWIGT-83 and UWIGT-120 (Burkholderia sp.) showed enhanced growth in germination assays and in greenhouse trials with Capsicum chinense (Moruga red hot peppers) under drought stress, when compared to non-inoculated treatments. The findings highlight the importance of testing interactivity of bacterial species with multiple growth promoting traits under stress conditions; and proposed the use of ACC growth media as a novel biofilm screening method for selecting potential stress plant growth-promoting bacteria. Better screening strategies for appropriate plant growth-promoting bacteria may narrow the inconsistency observed between laboratory and field trials.

Exploring diversity and functional traits of lactic acid bacteria in traditional vinegar fermentation: A review.

Vinegar has been used for centuries as a food preservative, flavor enhancer, and medicinal agent. While commonly known for its sour taste and acidic properties due to acetic acid bacteria metabolism, vinegar is also home to a diverse community of lactic acid bacteria (LAB). The main genera found during natural fermentation include Lactobacillus, Lacticaseibacillus, Lentilactobacillus, Limosilactbacillus, Leuconostoc, and Pedicoccus. Many of the reported LAB species fulfill the probiotic criteria set by the World Health Organization (WHO). However, it is crucial to acknowledge that LAB viability undergoes a significant reduction during vinegar fermentation. While containing LAB, none of the analyzed vinegar met the minimum viable amount required for probiotic labeling. To fully unlock the potential of vinegar as a probiotic, investigations should be focused on enhancing LAB viability during vinegar fermentation, identifying strains with probiotic properties, and establishing appropriate dosage and consumption guidelines to ensure functional benefits. Currently, vinegar exhibits substantial potential as a postbiotic product, attributed to the high incidence and growth of LAB in the initial stages of the fermentation process. This review aims to identify critical gaps and address the essential requirements for establishing vinegar as a viable probiotic product. It comprehensively examines various relevant aspects, including vinegar processing, total and LAB diversity, LAB metabolism, the potential health benefits linked to vinegar consumption, and the identification of potential probiotic species.

Primera evidencia de actividad enzimática nitrilasa en Xylaria sp., y su relación con la biosíntesis de ácido indol-3-acético / First evidence of nitrilase enzymatic activity of Xylaria sp. and its relationship with the biosynthesis of indole-3-acetic acid

Resumen Muchos de los hongos degradadores de madera están implicados en la síntesis de metabolitos bioactivos de naturaleza antimicrobiana y terapéutica, así como de compuestos de importancia biotecnológica, incluyendo derivados indólicos, entre otros. Estos hongos brindan ciertos beneficios ecológicos a las plantas, entre los que se destacan la protección contra fitopatógenos y la promoción del crecimiento radicular. Xylaria sp. es un hongo degradador de celulosa (lignocelulolítico) con potencial biotecnológico. El ácido indol-3-acético (AIA) desempeña un papel sumamente importante en las interacciones planta-microorganismo, ya que es esencial para la fisiología y el correcto desarrollo morfológico vegetal. Se sabe que las enzimas nitrilo-hidrolíticas (nitrilasas) están involucradas en la síntesis de compuestos indólicos en las plantas, no obstante, se dispone de poca información acerca de la naturaleza de estas enzimas en el reino de los hongos. A través de una aproximación bioquímica y de genética molecular, se demuestra por primera vez que Xylaria sp. posee actividad enzimática nitrilasa utilizando compuestos ricos en nitrógeno y carbono como sustrato. La cepa estudiada aumentó sus niveles de expresión génica relativa y mostró crecimiento micelial, ambos en presencia de compuestos químicos como cianobenceno y KCN. Los resultados de este trabajo sugieren que el microorganismo es capaz de degradar moléculas nitrogenadas complejas. Por otra parte, mediante biofertilización con extractos fúngicos, se observó que Xylaria sp. promueve el desarrollo del sistema radicular de plántulas de Arabidopsis thaliana, además de sintetizar AIA.

Abstract Endophytic fungi inhabit plant tissues internally and asymptomatically, and many of them are involved in the synthesis of bioactive metabolites of antifungal and therapeutic nature, as well as other compounds of biotechnological importance including indole derivatives, among many others. Ecologically, they provide some benefits to plants including protection against phy-topathogens and promotion of root growth. In this sense, Xylaria sp. is a cellulose-decomposing fungus with biotechnological potential. It is worth mentioning that indole-3-acetic acid (IAA) also plays an extremely important role in plant-micro-organism interactions, as it is essential for physiology and proper plant morphological development. It is known that nitrile-hydrolytic enzymes (nitrilases) are involved in the synthesis of plant indole compounds; however, relatively little information is available concerning the nature of these enzymes in the fungal kingdom. In view of the above, through a biochemical and molecular-genetic approach, it has been demon-strated for the first time that Xylaria sp. carries out nitrile-hydrolytic enzyme activity using nitrogen and carbonrich compounds as substrate. The studied strain increased its relative gene expression levels and showed mycelial growth, both in the presence of chemical compounds such as cyanobenzene and KCN. Thus, the results of this work suggest that the micro-organism is capable of degrading complex nitrogenous molecules. On the other hand, through fungal biofertilization, it was observed that Xylaria sp. promotes the development of the root system of Arabidopsis thaliana seedlings, in addition to synthesizing IAA.

Comparative metatranscriptome analysis of Brazilian milk and water kefir beverages.

The present study compared bacterial and fungal diversity of kefir beverages produced using milk (MK) or sugared water (WK) as propagation matrices and grains from the cities of Curitiba (CU) or Salvador (SA), Brazil, by sequencing the complete set of RNA transcripts produced in four products. In Brazil, milk and sugared water are used as matrices to propagate kefir grains. In all beverages, the bacterial community was composed of Lactobacillaceae and Acetobacteraceae. Saccharomycetaceae was the yeast family more abundant in WK, and Dipodascaceae and Pichiaceae in MK. Regarding KEGG mapping of functional orthologs, the four kefir samples shared 70% of KO entries of yeast genes but only 36% of bacterial genes. Concerning main metabolic processes, the relative abundance of transcripts associated with metabolism (energy metabolism) and environmental information processing (membrane transport) had the highest water/milk kefir ratio observed in Firmicutes. In contrast, transcripts associated with genetic information processing (protein translation, folding, sorting, and degradation) oppositely had the lowest water/milk ratios. Concluding, milk and water kefir have quite different communities of microorganisms. Still, the main mapped functional processes are similar, with only quantitative variation in membrane transport and energy acquisition in the water kefir and protein synthesis and turnover in the milk kefir.

Two-dimensional chromatography for enantiomeric analysis of mitotane and its metabolite o,p'-DDA in patients with adrenocortical carcinoma indicates enantioselective metabolism.

Mitotane is a chiral drug used to treat adrenocortical carcinoma, being metabolized to the o,p'-dichlorodiphenyl acetic acid (o,p'-DDA), also a chiral compound. Despite of its therapeutic significance, the overall ratios and enantiomers have not been known. In this study, we analyzed the enantiomers of mitotane and o,p'-DDA in the plasma of patients by a newly developed chiral-phase method employed in two-dimensional chromatography. Important differences were observed in the ratio of (S)/(R)-mitotane, which varied substantially from 1:1.2 to 1:10 whereas the (S)/(R)-o,p'-DDA ratio was relatively conserved, at approximately 2:1. These findings provide evidence for the enantioselective metabolism and provide a method for further analyses of mitotane and metabolites, which can explain the variation in the therapeutic response.

Squamocolumnar junction visibility among cervical cancer screening population in Peru might influence upper age for screening programs.

Cervical cancer screening and treatment of screen positives is an important and effective strategy to reduce cervical cancer morbidity and mortality. In order to have an accurate cervical cancer screening and evaluation of positives, the entire Squamocolumnar Junction (SCJ) must be visible. Throughout the life course, the position of the SCJ changes and affects its visibility. SCJ visibility was analyzed among participants screened at the League Against Cancer Clinic in Lima, Peru. Of the 4247 participants screened, the SCJ was fully visible in 49.7% of participants, partially visible in 23.1%, and not visible in 27.2%. Visibility decreased with age, and by age 45 years old, the SCJ was not fully visible in over 50% of participants. Our results show that a high percentage of participants at ages still recommended for screening do not have totally visible SCJ, and we may need to reconsider the upper age limit for screening and find new strategies for evaluation of those with a positive screening test and non-visible SCJ.

Electrobiochemical skills of Pseudomonas aeruginosa species that produce pyocyanin or pyoverdine for glycerol oxidation in a microbial fuel cell.

Pseudomonas aeruginosa can produce pigments, which mediate external electron transfer (EET). Depending on the mediator, this species can be explored in bioelectrosystems to harvest energy or to obtain chemicals from residual organic compounds. This study has compared the performance of microbial fuel cells (MFCs) inoculated with a Pseudomonas aeruginosa isolate, namely EW603 or EW819, which produce pyocyanin and pyoverdine, respectively. The efficiency of these MFCs in glycerol, a typical residue of biodiesel production, were also compared. The MFCs exhibited different performances. The maximum voltage was 411 and 281 mV m2, the power density was 40.1 and 21.3 mW m-2, and the coulombic efficiency was 5.16 and 1.49% for MFC-EW603 and MFC-EW819, respectively. MFC-EW603 and MFC-EW819 achieved maximum current at 560 and 2200 Ω, at 141.2 and 91.3 mA m-2, respectively. When the system was operated at the respective maximum current output, MFC-EW603 consumed the total glycerol content (11 mmol L-1), and no products could be detected after 50 h. In turn, acetic and butyric acids were detected at the end of MFC-EW819 operation (75 h). The results suggested that P. aeruginosa metabolism can be steered in the MFC to generate current or microbial products depending on the pigment-producing strain and the conditions applied to the system, such as the external resistance. In addition, gene cluster pathways related to phenazine production (phzA and phzB) and other electrogenic-related genes (mexGHI-opmB) were identified in the strain genomes, supporting the findings. These results open new possibilities for using glycerol in bioelectrochemical systems.

Lysinibacillus spp.: an IAA-producing endospore forming-bacteria that promotes plant growth.

Lysinibacillus is a bacterial genus that has generated recent interest for its biotechnological potential in agriculture. Strains belonging to this group are recognized for their mosquitocidal and bioremediation activity. However, in recent years some reports indicate its importance as plant growth promoting rhizobacteria (PGPR). This research sought to provide evidence of the PGP activity of Lysinibacillus spp. and the role of the indole-3-acetic acid (IAA) production associated with this activity. Twelve Lysinibacillus spp. strains were evaluated under greenhouse conditions, six of which increased the biomass and root architecture of corn plants. In most cases, growth stimulation was evident at 108 CFU/mL inoculum concentration. All strains produced IAA with high variation between them (20-70 µg/mL). The bioinformatic identification of predicted genes associated with IAA production allowed the detection of the indole pyruvic acid pathway to synthesize IAA in all strains; additionally, genes for a tryptamine pathway were detected in two strains. Extracellular filtrates from all strain's cultures increased the corn coleoptile length in an IAA-similar concentration pattern, which demonstrates the filtrates had an auxin-like effect on plant tissue. Five of the six strains that previously showed PGPR activity in corn also promoted the growth of Arabidopsis thaliana (col 0). These strains induced changes in root architecture of Arabidopsis mutant plants (aux1-7/axr4-2), the partial reversion of mutant phenotype indicated the role of IAA on plant growth. This work provided solid evidence of the association of Lysinibacillus spp. IAA production with their PGP activity, which constitutes a new approach for this genus. These elements contribute to the biotechnological exploration of this bacterial genus for agricultural biotechnology.

Role of Acetic Acid Bacteria in Food and Beverages.

Acetic acid bacteria (AAB) are microorganisms widely distributed in nature. Although this group is involved in the spoilage of some foods, AAB are of great industrial interest, and their functionality is still poorly understood. AAB convert ethanol, sugars and polyols into various organic acids, aldehydes and ketones via oxidative fermentation. These metabolites are produced during a succession of biochemical reactions in various fermented foods and beverages, such as vinegar, kombucha, water kefir, lambic and cocoa. Furthermore, important products such as gluconic acid and ascorbic acid precursors can be produced industrially from their metabolism. The development of new AAB-fermented fruit drinks with healthy and functional properties is an interesting niche for research and the food industry to explore, as it can meet the needs of a wide range of consumers. Exopolysaccharides such as levan and bacterial cellulose have unique properties, but they need to be produced on a larger scale to expand their applications in this area. This work emphasizes the importance and applications of AAB during the fermentation of various foods, their role in the development of new beverages as well as numerous applications of levan and bacterial cellulose.

Exogenous Auxin and Gibberellin on Fluoride Phytoremediation by Eichhornia crassipes.

High rates of fluorosis were reported worldwide as a result of human consumption of water with fluoride contents. Adjusting fluoride concentration in water as recommended by the World Health Organization (<1.5 mg L-1) is a concern and it needs to be conducted through inexpensive, but efficient techniques, such as phytoremediation. The application of phytohormones was investigated as a strategy to improve this process. Thus, the main goal of this research was to evaluate the effect of exogenous auxin and gibberellin on the tropical duckweed Eichhornia crassipes performance for fluoride phytoremediation. Definitive screening and central composite rotatable designs were used for experiments where fluoride concentration (5~15 mg L-1), phosphorus concentration (1~10 mg L-1), and pH (5~9) were assessed as well throughout 10 days. Fluoride contents were determined in solution and plant tissues by potentiometry. Higher concentrations of fluoride reflected on greater absorptions by plants, though in relative terms removal efficiencies were quite similar for all treatments (~60%). Auxin and acidic conditions favored fluoride removals per mass of plant. Fluoride accumulated mostly in leaves and auxin probably alleviated toxic effects on E. crassipes while gibberellin showed no effect. Therefore, E. crassipes could be employed as a fluoride accumulator plant for water treatment and exogenous auxin may be used to improve the process.

[First evidence of nitrilase enzymatic activity of Xylaria sp. and its relationship with the biosynthesis of indole-3-acetic acid]. / Primera evidencia de actividad enzimática nitrilasa en Xylaria sp., y su relación con la biosíntesis de ácido indol-3-acético.

Endophytic fungi inhabit plant tissues internally and asymptomatically, and many of them are involved in the synthesis of bioactive metabolites of antifungal and therapeutic nature, as well as other compounds of biotechnological importance including indole derivatives, among many others. Ecologically, they provide some benefits to plants including protection against phytopathogens and promotion of root growth. In this sense, Xylaria sp. is a cellulose-decomposing fungus with biotechnological potential. It is worth mentioning that indole-3-acetic acid (IAA) also plays an extremely important role in plant-micro-organism interactions, as it is essential for physiology and proper plant morphological development. It is known that nitrile-hydrolytic enzymes (nitrilases) are involved in the synthesis of plant indole compounds; however, relatively little information is available concerning the nature of these enzymes in the fungal kingdom. In view of the above, through a biochemical and molecular-genetic approach, it has been demonstrated for the first time that Xylaria sp. carries out nitrile-hydrolytic enzyme activity using nitrogen and carbon-rich compounds as substrate. The studied strain increased its relative gene expression levels and showed mycelial growth, both in the presence of chemical compounds such as cyanobenzene and KCN. Thus, the results of this work suggest that the micro-organism is capable of degrading complex nitrogenous molecules. On the other hand, through fungal biofertilization, it was observed that Xylaria sp. promotes the development of the root system of Arabidopsis thaliana seedlings, in addition to synthesizing IAA.