Electrostatic Fermentation: Molecular Response Insights for Tailored Beer Production.

Electrostatic fermentation avoids the cellular redox imbalance of traditional fermentation, but knowledge gaps exist. This study explores the impact of electrostatic fermentation on the growth, volatile profile, and genetic response of Saccharomyces pastorianus Saflager S-23. The applied voltage (15 and 30 V) in the electrostatic fermentation system increased the growth and substrate utilization of S. pastorianus while decreasing ethanol production. The aromas typically associated with traditional fermentation, such as alcoholic, grape, apple, and sweet notes, were diminished, while aromas like roses, fruits, flowers, and bananas were augmented in electrostatic fermentation. RNA-seq analysis revealed upregulation of genes involved in cell wall structure, oxidoreductase activity, and iron ion binding, while genes associated with protein synthesis, growth control, homeostasis, and membrane function were downregulated under the influence of applied voltage. The electrostatic fermentation system modulates genetic responses and metabolic pathways in yeast, rendering it a promising method for tailored beer production. Demonstrating feasibility under industrial-scale and realistic conditions is crucial for advancing towards commercialization.

A Study of Resistome in Mexican Chili Powder as a Public Health Risk Factor.

Chili powder is an important condiment around the world. However, according to various reports, the presence of pathogenic microorganisms could present a public health risk factor during its consumption. Therefore, microbiological quality assessment is required to understand key microbial functional traits, such as antibiotic resistance genes (ARGs). In this study, metagenomic next-generation sequencing (mNGS) and bioinformatics analysis were used to characterize the comprehensive profiles of the bacterial community and antibiotic resistance genes (ARGs) in 15 chili powder samples from different regions of Mexico. The initial bacterial load showed aerobic mesophilic bacteria (AMB) ranging between 6 × 103 and 7 × 108 CFU/g, sporulated mesophilic bacteria (SMB) from 4.3 × 103 to 2 × 109 CFU/g, and enterobacteria (En) from <100 to 2.3 × 106 CFU/g. The most representative families in the samples were Bacillaceae and Enterobacteriaceae, in which 18 potential pathogen-associated species were detected. In total, the resistome profile in the chili powder contained 68 unique genes, which conferred antibiotic resistance distributed in 13 different classes. Among the main classes of antibiotic resistance genes with a high abundance in almost all the samples were those related to multidrug, tetracycline, beta-lactam, aminoglycoside, and phenicol resistance. Our findings reveal the utility of mNGS in elucidating microbiological quality in chili powder to reduce the public health risks and the spread of potential pathogens with antibiotic resistance mechanisms.

Volatile Organic Compounds Produced by Kosakonia cowanii Cp1 Isolated from the Seeds of Capsicum pubescens R & P Possess Antifungal Activity.

The Kosakonia cowanii Cp1 strain was isolated from seeds of Capsicum pubescens R. & P. cultivated in Michoacan, Mexico. Genetic and ecological role analyses were conducted for better characterization. The results show that genome has a length of 4.7 Mbp with 56.22% G + C and an IncF plasmid of 128 Kbp with 52.51% G + C. Furthermore, pathogenicity test revealed nonpathogenic traits confirmed by the absence of specific virulence-related genes. Interestingly, when fungal inhibitory essays were carried out, the bacterial synthesis of volatile organic compounds (VOCs) with antifungal activity showed that Sclerotinia sp. and Rhizoctonia solani were inhibited by 87.45% and 77.24%, respectively. Meanwhile, Sclerotium rolfsii, Alternaria alternata, and Colletotrichum gloeosporioides demonstrated a mean radial growth inhibition of 52.79%, 40.82%, and 55.40%, respectively. The lowest inhibition was by Fusarium oxysporum, with 10.64%. The VOCs' characterization by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) revealed 65 potential compounds. Some of the compounds identified with high relative abundance were ketones (22.47%), represented by 2-butanone, 3-hydroxy (13.52%), and alcohols (23.5%), represented by ethanol (5.56%) and 1-butanol-3-methyl (4.83%). Our findings revealed, for the first time, that K. cowanii Cp1 associated with C. pubescens seeds possesses potential traits indicating that it could serve as an effective biocontrol.

Evaluation of the Insecticidal Potential of Heterotheca inuloides Acetonic and Methanolic Extracts against Spodoptera frugiperda and Their Ecotoxicological Effect on Poecilia reticulata.

For the management of Spodoptera frugiperda, botanical extracts have been used to reduce the environmental impacts of synthetic chemical pesticides. In the present investigation, the insecticidal activity of the acetonic and methanolic extracts of Heterotheca inuloides (Asteraceae) and of the main compound 7-hydroxy-3,4-dihydrocadalene on this pest as well as its ecotoxicological effect on Poecilia reticulata were evaluated. A greater insecticidal response was obtained from the acetonic extracts than from the methanolic extracts, with LC50 values of 730.4 ppm and 711.7 ppm for samples 1 and 2, respectively. Similarly, there was a lethal effect on 50% of the P. reticulata population at low concentrations in the acetonic extract compared to the methanolic extract. The sesquiterpene 7-hydroxy-3,4-dihydrocadalene has greater insecticidal activity by presenting an LC50 of 44.36 ppm; however, it is classified as moderately toxic for guppy fish.

Kosakonia cowanii Ch1 Isolated from Mexican Chili Powder Reveals Growth Inhibition of Phytopathogenic Fungi.

Kosakonia cowanii strain Ch1 was isolated from Mexican chili powder, and the genome was sequenced. The genome was 4,765,544 bp in length, with an average G + C content of 56.22%, and a plasmid (pCh1) of 128,063 bp with an average G + C content of 52.50%. A phylogenetic analysis revealed a close relation with pathogenic strains; nevertheless, some virulence-related genes were absent, and this genetic characteristic may explain the fact that K. cowanii Ch1 behaved as a non-pathogenic strain when infection assays were performed on the leaves and fruits of Capsicum annuum L. Surprisingly, we observed that this bacterial strain had the ability to spread throughout serrano pepper seeds. Furthermore, K. cowanii Ch1 was evaluated for the production of volatile organic compounds (VOCs) against fungal pathogens, and the results showed that Alternaria alternata and Sclerotium rolfsii were inhibited in a radial mycelial growth assay by a mean rate of 70% and 64%, while Fusarium oxysporum was inhibited by only approximately 10%. Based on the headspace solid-phase microextraction combined with the gas chromatography mass spectrometry (HS-SPME-GC-MS), 67 potential VOCs were identified during the fermentation of K. cowanii Ch1 in TSA medium. From these VOCs, nine main compounds were identified based on relative peak area: dodecanoic acid; 3-hydroxy ethanol; 1-butanol-3-methyl; acetaldehyde; butanoic acid, butyl ester; cyclodecane; 2-butanone, 3-hydroxy; disulfide, dimethyl and pyrazine-2,5-dimethyl. Our findings show the potential of K. cowanii Ch1 for the biocontrol of fungal pathogens through VOCs production and reveal additional abilities and metabolic features as beneficial bacterial specie.

Sargassum@magnetite Composite EDTA-Functionalized for the Potential Removal of Mercury.

Sargassum spp. affects the Caribbean shores; thus, its remotion or valorization is a priority. This work aimed to synthesize a low-cost magnetically retrievable Hg+2 adsorbent functionalized with ethylenediaminetetraacetic acid (EDTA) based on Sargassum. The Sargassum was solubilized to synthesize by co-precipitation a magnetic composite. A central composite design was assessed to maximize the adsorption of Hg+2. The solids yield magnetically attracted mass, and the saturation magnetizations of the functionalized composite were 60.1 ± 17.2%, 75.9 ± 6.6%, and 1.4 emu g-1. The functionalized magnetic composite yielded 29.8 ± 0.75 mg Hg+2 g-1 of chemisorption after 12 h, pH 5, and 25 °C achieving 75% Hg+2 adsorption after four reuse cycles. Crosslinking and functionalization with Fe3O4 and EDTA created differences in surface roughness as well as the thermal events of the composites. The Fe3O4@Sargassum@EDTA composite was a magnetically recovered biosorbent of Hg2+.

Insights into the Bacterial Diversity and Detection of Opportunistic Pathogens in Mexican Chili Powder.

Chili powder is the most frequently consumed spice in Mexican diets. Thus, the dissemination of microorganisms associated with chili powder derived from Capsicum annuum L. is significant during microbial quality analysis, with special attention on detection of potential pathogens. The results presented here describe the initial characterization of bacterial community structure in commercial chili powder samples. Our results demonstrate that, within the domain Bacteria, the most abundant family was Bacillaceae, with a relative abundance of 99% in 71.4% of chili powder samples, while 28.6% of samples showed an average relative abundance of 60% for the Enterobacteriaceae family. Bacterial load for aerobic mesophilic bacteria (AMB) ranged from 104 to 106 cfu/g, while for sporulated mesophilic bacteria (SMB), the count ranged from 102 to 105 cfu/g. Bacillus cereus sensu lato (s.l.) was observed at ca. ˂600 cfu/g, while the count for Enterobacteriaceae ranged from 103 to 106 cfu/g, Escherichia coli and Salmonella were not detected. Fungal and yeast counts ranged from 102 to 105 cfu/g. Further analysis of the opportunistic pathogens isolated, such as B. cereus s.l. and Kosakonia cowanii, using antibiotic-resistance profiles and toxinogenic characteristics, revealed the presence of extended-spectrum ß-lactamases (ESBLs) and Metallo-ß-lactamases (MBLs) in these organisms. These results extend our knowledge of bacterial diversity and the presence of opportunistic pathogens associated with Mexican chili powder and highlight the potential health risks posed by its use through the spread of antibiotic-resistance and the production of various toxins. Our findings may be useful in developing procedures for microbial control during chili powder production.

Effect of Salicylic Acid in the Yield of Ricinine in Ricinus communis under Greenhouse Condition.

Castor bean (Ricinus communis) seeds contain ricinine, an alkaloid with insecticidal and insectistatic activities. Elicitation with salicylic acid (SA) has proven to stress R. communis and might modify the ricinine concentration. The aim of this study was to evaluate the concentration of ricinine in the bagasse of seeds from R. communis elicited with exogenous SA under greenhouse conditions. Plants were grown and divided into five groups, which were sprayed with SA and drench with 50 mL 60 days after sowing with concentrations of SA (0, 100, 300, 600 and 900 µM). Clusters were mixed and separated according to the treatment, and dried. The seeds were ground, the oil was extracted by Soxhlet with hexane, and then the bagasse was extracted with methanol. Ricinine was determined by HPLC. Elicitation did not change the plant height or diameter; the control group had 9.17 µg mL-1 of ricinine; and the concentrations followed a hormesis curve with the peak at 300 µM of SA that had a ricinine concentration of 18.25 µg mL-1. Elicitation with SA might be a cost-effective technique to increase ricinine from R. communis bagasse.

Richness and metallo-tolerance of cultivable fungi recovered from three high altitude glaciers from Citlaltépetl and Iztaccíhuatl volcanoes (Mexico).

In Mexico little is known about high-altitude glacial psychrotolerant or psychrophilic fungal species, with most glacial fungi isolated from polar environments or Alpine glaciers. It has been documented that some of these species may play an important role in bioremediation of contaminated environments with heavy metals. In the present study, 75 fungi were isolated from glaciers in Citlaltépetl (5675 masl) and Iztaccíhuatl (5286 masl) volcanoes. Combining morphological characteristics and molecular methods, based on ITS rDNA, 38 fungi were partially identified to genus level, 35 belonging to Ascomycota and three to Mucoromycota. The most abundant genera were Cladosporium, followed by Alternaria and Sordariomycetes order. All isolated fungi were psychrotolerant, pigmented and resistant to different concentrations of Cr(III) and Pb(II), while none tolerated Hg(II). Fungi most tolerant to Cr(III) and Pb(II) belong to the genera Stemphylium, Cladosporium and Penicillium and to a lesser extent Aureobasidium and Sordariomycetes. To our knowledge, this is the first report on cultivable mycobiota richness and their Cr and Pb tolerance. The results open new research possibilities about fungal diversity and heavy metals myco-remediation. Extremophilic fungal communities should be further investigated before global warming causes permanent changes and we miss the opportunity to describe these sites in Mexico.

Phylogenetic Analysis of Bacillus cereus sensu lato Isolates from Commercial Bee Pollen Using tRNACys-PCR.

Endospore-forming bacteria related to the Bacillus cereus group produce toxins that cause illnesses in organisms from invertebrates to mammals, including foodborne illnesses in humans. As commercial bee pollen can be contaminated with these bacteria, a comprehensive microbiological risk assessment of commercial bee pollen must be incorporated into the relevant regulatory requirements, including those that apply in Mexico. To facilitate detection of members of this group of bacteria, we have developed a PCR strategy that is based on the amplification of the single-copy tRNACys gene and specific genes associated with tRNACys to detect Bacillus cereus sensu lato (B. cereus s.l.). This tRNACys-PCR-based approach was used to examine commercial bee pollen for endospore-forming bacteria. Our analysis revealed that 3% of the endospore-forming colonies isolated from a commercial source of bee pollen were related to B. cereus s.l., and this result was corroborated by phylogenetic analysis, bacterial identification via MALDI-TOF MS, and detection of enterotoxin genes encoding the HBL and NHE complexes. The results show that the isolated colonies are closely related phylogenetically to B. cereus, B. thuringiensis, and B. bombysepticus. Our results indicate that the tRNACys-PCR, combined with other molecular tools, will be a useful approach for identifying B. cereus s.l. and will assist in controlling the spread of potential pathogens.

Analysis of tRNA Cys processing under salt stress in Bacillus subtilis spore outgrowth using RNA sequencing data.

Background: In spore-forming bacteria, the molecular mechanisms of accumulation of transfer RNA (tRNA) during sporulation must be a priority as tRNAs play an essential role in protein synthesis during spore germination and outgrowth. However, tRNA processing has not been extensively studied in these conditions, and knowledge of these mechanisms is important to understand long-term stress survival.    Methods:To gain further insight into tRNA processing during spore germination and outgrowth, the expression of the single copy tRNA Cys gene was analyzed in the presence and absence of 1.2 M NaCl in Bacillus subtilis using RNA-Seq data obtained from the Gene Expression Omnibus (GEO) database. The CLC Genomics work bench 12.0.2 (CLC Bio, Aarhus, Denmark, https://www.qiagenbioinformatics.com/) was used to analyze reads from the tRNA Cys gene.  Results:The results show that spores store different populations of tRNA Cys-related molecules.  One such population, representing 60% of total tRNA Cys, was composed of tRNA Cys fragments.  Half of these fragments (3´-tRF) possessed CC, CCA or incorrect additions at the 3´end. tRNA Cys with correct CCA addition at the 3´end represented 23% of total tRNA Cys, while with CC addition represented 9% of the total and with incorrect addition represented 7%. While an accumulation of tRNA Cys precursors was induced by upregulation of the rrnD operon under the control of  σ A -dependent promoters under both conditions investigated, salt stress produced only a modest effect on tRNA Cys expression and the accumulation of tRNA Cys related species. Conclusions:The results demonstrate that tRNA Cys molecules resident in spores undergo dynamic processing to produce functional molecules that may play an essential role during protein synthesis.

Analysis of tRNACys processing in the absence of CCAase in Bacillus subtilis.

In Bacillus subtilis, the tRNACys lacks an encoded CCA 3' end. To gain insight into the role of CCAase and RNases in tRNACys processing, several mutant strains were generated. Northern blot and RT-PCR results suggest that enzymes other than CCAase can participate in CCA addition at the 3' end of the immature tRNACys.

Production of a Mixture of Fengycins with Surfactant and Antifungal Activities by Bacillus sp. MA04, a Versatile PGPR.

Bacillus sp. strain MA04 a plant growth-promoting rhizobacteria (PGPR) showed hemolytic activity on blood agar plates, and the supernatant from liquid culture in nutrient broth at 24 h exhibited emulsification activity, suggesting the production of biosurfactants. In antagonist assays, the supernatant showed antifungal activity against phytopathogenic fungi such as Penicillium expansum, Fusarium stilboides, Sclerotium rolfsii y Rhizoctonia solani, finding a reduction of mycelial growth of all fungi tested, ranging from 35 to 69%, this activity was increased with time of culture, accomplishing percentages of inhibition up to 85% with supernatants obtained at 72 h. Then, the crude biorsurfactant (CB) was isolated from the supernatant in order to assay its antagonistic effect on the phytopathogens previously tested, finding an increase in the inhibition up to 97% at 500 mg/L of CB. The composition of CB was determined by infrared spectroscopy, identifying various functional groups related to lipopeptides, which were purified by high-performance liquid chromatography and analyzed by MALDI-TOF/TOF-MS, revealing a mixture of fengycins A and B whose high antifungal activity is been widely recognized. These results show that PGPR Bacillus sp. MA04 could also contribute to plant health status through the production of metabolites with antimicrobial activity.

Composition of the Essential Oil of Salvia ballotiflora (Lamiaceae) and Its Insecticidal Activity.

Essential oils can be used as an alternative to using synthetic insecticides for pest management. Therefore, the insectistatic and insecticidal activities of the essential oil of aerial parts of Salvia ballotiflora (Lamiaceae) were tested against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The results demonstrated insecticidal and insectistatical activities against this insect pest with concentrations at 80 µg·mL(-1) resulting in 20% larval viability and 10% pupal viability. The larval viability fifty (LV50) corresponded to a concentration of 128.8 µg·mL(-1). This oil also increased the duration of the larval phase by 5.5 days and reduced the pupal weight by 29.2% withrespect to the control. The GC-MS analysis of the essential oil of S. ballotiflora showed its main components to be caryophyllene oxide (15.97%), and ß-caryophyllene (12.74%), which showed insecticidal and insectistatical activities against S. frugiperda. The insecticidal activity of ß-caryophyllene began at 80 µg·mL(-1), giving a larval viability of 25% and viability pupal of 20%. The insectistatic activity also started at 80 µg·mL(-1) reducing the pupal weight by 22.1% with respect to control. Caryophyllene oxide showed insecticidal activity at 80 µg·mL(-1) giving a larval viability of 35% and viability pupal of 20%.The insectistatic activity started at 400 µg·mL(-1) and increased the larval phase by 8.8% days with respect to control. The LV50 values for these compounds were 153.1 and 146.5 µg·mL(-1), respectively.

Bioactivity of Carica papaya (Caricaceae) against Spodoptera frugiperda (Lepidoptera: Noctuidae).

The composition of a chloroform seed extract of C. papaya was determined by GC-MS. Nineteen compounds were identified, with oleic (45.97%), palmitic (24.1%) and stearic (8.52%) acids being the main components. The insecticidal and insectistatic activities of the extract and the three main constituents were tested. Larval duration increased by 3.4 d and 2.5 d when the extract was used at 16,000 and 9,600 ppm, respectively, whereas the pupal period increased by 2.2 d and 1.1 d at the same concentrations. Larval viability values were 0%, 29.2%, and 50% when the extract was applied at 24,000, 16,000, and 9,600 ppm, respectively; pupal viability was 42.9% and 66.7% at 16,000 and 9,600 ppm; and pupal weight decreased by 25.4% and 11.5% at 16,000 and 9,600 ppm. The larval viability of the main compounds was 33.3%, 48.5%, and 62.5% when exposed to 1,600 ppm of palmitic acid, oleic acid, or stearic acid, respectively.