Growth Performance and Fecal Microbiota of Dairy Calves Supplemented with Autochthonous Lactic Acid Bacteria as Probiotics in Mexican Western Family Dairy Farming.

Probiotic supplementation in dairy cattle has achieved several beneficial effects (improved growth rate, immune response, and adequate ruminal microbiota). This study assessed the effects on the growth parameters and gut microbiota of newborn dairy calves supplemented with two Lactobacillus-based probiotics, individually (6BZ or 6BY) or their combination (6BZ + 6BY), administrated with the same concentration (1 × 109 CFU/kg weight) at three times, between days 5 and 19 after birth. The control group consisted of probiotic-unsupplemented calves. Growth parameters were recorded weekly until eight weeks and at the calves' ages of three, four, and five months. Fecal microbiota was described by high-throughput sequencing and bioinformatics. Although no significant effects were observed regarding daily weight and height gain among probiotic-supplemented and non-supplemented calves, correlation analysis showed that growth rate was maintained until month 5 through probiotic supplementation, mainly when the two-strain probiotics were supplied. Modulation effects on microbiota were observed in probiotic-supplemented calves, improving the Bacteroidota: Firmicutes and the Proteobacteria ratios. Functional prediction by PICRUSt also showed an increment in several pathways when the two-strain probiotic was supplemented. Therefore, using the three-administration scheme, the two-strain probiotic improved the growth rate and gut microbiota profile in newborn dairy calves. However, positive effects could be reached by applying more administrations of the probiotic during the first 20 days of a calf's life.

Promotion of the growth and yield of Zea mays by synthetic microbial communities from Jala maize.

Plant growth-promoting bacteria (PGPB) are a source of nutrient supply, stimulate plant growth, and even act in the biocontrol of phytopathogens. However, these phenotypic traits have rarely been explored in culturable bacteria from native maize landraces. In this study, synthetic microbial communities (SynCom) were assembled with a set of PGPB isolated from the Jala maize landrace, some of them with additional abilities for the biocontrol of phytopathogenic fungi and the stimulation of plant-induced systemic resistance (ISR). Three SynCom were designed considering the phenotypic traits of bacterial strains, including Achromobacter xylosoxidans Z2K8, Burkholderia sp. Z1AL11, Klebsiella variicola R3J3HD7, Kosakonia pseudosacchari Z2WD1, Pantoea ananatis E2HD8, Pantoea sp. E2AD2, Phytobacter diazotrophicus Z2WL1, Pseudomonas protegens E1BL2, and P. protegens E2HL9. Plant growth promotion in gnotobiotic and greenhouse seedlings assays was performed with Conejo landrace; meanwhile, open field tests were carried out on hybrid CPL9105W maize. In all experimental models, a significant promotion of plant growth was observed. In gnotobiotic assays, the roots and shoot length of the maize seedlings increased 4.2 and 3.0 times, respectively, compared to the untreated control. Similarly, the sizes and weights of the roots and shoots of the plants increased significantly in the greenhouse assays. In the open field assay performed with hybrid CPL9105W maize, the yield increased from 11 tons/ha for the control to 16 tons/ha inoculated with SynCom 3. In addition, the incidence of rust fungal infections decreased significantly from 12.5% in the control to 8% in the treatment with SynCom 3. All SynCom designs promoted the growth of maize in all assays. However, SynCom 3 formulated with A. xylosoxidans Z2K8, Burkholderia sp. Z1AL11, K. variicola R3J3HD7, P. ananatis E2HD8, P. diazotrophicus Z2WL1, and P. protegens E1BL2 displayed the best results for promoting plant growth, their yield, and the inhibition of fungal rust. This study demonstrated the biotechnological eco-friendly plant growth-promoting potential of SynCom assemblies with culturable bacteria from native maize landraces for more sustainable and economic agriculture.

A Look at Plant-Growth-Promoting Bacteria.

Bacteria have been used to increase crop yields. For their application on crops, bacteria are provided in inoculant formulations that are continuously changing, with liquid- and solid-based products. Bacteria for inoculants are mainly selected from natural isolates. In nature, microorganisms that favor plants exhibit various strategies to succeed and prevail in the rhizosphere, such as biological nitrogen fixation, phosphorus solubilization, and siderophore production. On the other hand, plants have strategies to maintain beneficial microorganisms, such as the exudation of chemoattractanst for specific microorganisms and signaling pathways that regulate plant-bacteria interactions. Transcriptomic approaches are helpful in attempting to elucidate plant-microorganism interactions. Here, we present a review of these issues.

Physiological Effects and Human Health Benefits of Hibiscus sabdariffa: A Review of Clinical Trials.

Hibiscus sabdariffa Linn. Malvaceae (HS) is characterized by its edible calyxes. The HS calyxes are widely used for cosmetic, food, and medicinal applications. According to ethnobotanical evidence, decoction, infusion, or maceration extracts from HS calyxes have been used in folk medicine to treat many ailments. Moreover, several in vitro and in vivo studies have demonstrated the pharmacological properties and potential human health benefits of HS consumption. On the other hand, the evaluation of the physiological effects and health benefits of HS in clinical studies is most challenging. Therefore, this narrative review summarizes and discusses the physiological effects and health benefits of HS calyxes reported in clinical trials. Preparations obtained from HS calyxes (extracts, infusions, decoction, teas, beverages, capsules, and pills) are used as non-pharmacological therapies to prevent/control diverse chronic non-communicable diseases. The most-reported HS health benefits are its antihypertensive, antidyslipidemic, hypoglycemic, body fat mass reduction, nephroprotective, antianemic, antioxidant, anti-inflammatory, and anti-xerostomic activities; these effects are associated with the phytochemicals found in HS. Moreover, no adverse effects were reported during the clinical trials. However, clinical studies exhibited some limitations; thus, further studies are required to validate the clinical efficacy of HS in large-scale studies with higher doses and a good experimental design.

Non-Antibiotics Strategies to Control Salmonella Infection in Poultry.

Salmonella spp. is a facultative intracellular pathogen causing localized or systemic infections, involving economic and public health significance, and remains the leading pathogen of food safety concern worldwide, with poultry being the primary transmission vector. Antibiotics have been the main strategy for Salmonella control for many years, which has allowed producers to improve the growth and health of food-producing animals. However, the utilization of antibiotics has been reconsidered since bacterial pathogens have established and shared a variety of antibiotic resistance mechanisms that can quickly increase within microbial communities. The use of alternatives to antibiotics has been recommended and successfully applied in many countries, leading to the core aim of this review, focused on (1) describing the importance of Salmonella infection in poultry and the effects associated with the use of antibiotics for disease control; (2) discussing the use of feeding-based (prebiotics, probiotics, bacterial subproducts, phytobiotics) and non-feeding-based (bacteriophages, in ovo injection, vaccines) strategies in poultry production for Salmonella control; and (3) exploring the use of complementary strategies, highlighting those based on -omics tools, to assess the effects of using the available antibiotic-free alternatives and their role in lowering dependency on the existing antimicrobial substances to manage bacterial infections in poultry effectively.

Allium-Based Phytobiotic for Laying Hens' Supplementation: Effects on Productivity, Egg Quality, and Fecal Microbiota.

The poultry industry is constantly demanding novel strategies to improve the productivity and health status of hens, prioritizing those based on the holistic use of natural resources. This study aimed to assess the effects of an Allium-based phytobiotic on productivity, egg quality, and fecal microbiota of laying hens. One hundred and ninety-two 14-week-old Lohmann Lite LSL hens were allocated into an experimental farm, fed with a commercial concentrate with and without the Allium-based phytobiotic, and challenged against Salmonella. Productivity, egg quality, and fecal microbiota were monitored for 20 weeks. Results showed that the phytobiotic caused an increase on the number of eggs laid (p < 0.05) and in the feed conversion rate (p < 0.05); meanwhile, egg quality, expressed as egg weight, albumin height, haugh units, egg shell strength, and egg shell thickness remained unchanged (p > 0.05), although yolk color was decreased. Fecal microbiota structure was also modified, indicating a modulation of the gut microbiota by increasing the presence of Firmicutes and Bacteroidetes but reducing Proteobacteria and Actinobacteria phyla. Predicted changes in the functional profiles of fecal microbiota suggest alterations in metabolic activities that could be responsible for the improvement and maintenance of productivity and egg quality when the phytobiotic was supplemented; thus, Allium-based phytobiotic has a major impact on the performance of laying hens associated with a possible gut microbiota modulation.

Functional characterization of culturable fungi from microbiomes of the "conical cobs" Mexican maize (Zea mays L.) landrace.

Mexican maize landraces, produced for local consumption, are adapted to different environmental conditions, and their yield is affected by abiotic and biotic factors, including the use of agrochemicals. The search for sustainable alternatives to agrochemicals includes the study of the culturable microbial communities. In this study, the fungal communities associated with 2 Mexican maize landraces reddish and bluish "conical cobs" were found to be comprised of Ascomycota fungi, represented by 89 strains within 6 orders (Pleosporales, Hypocreales, Onygenales, Capnodiales, Helotiales, and Eurotiales) and 16 genera. Cellulases and metallophores production were the primary enzymatic products and plant growth-promoting activities were detected among the isolates. Penicillium, Didymella, and Fusarium strains had the most active enzymatic and plant growth promoting activities, however, Aspergillus sp. HES2-2.2, Talaromyces sp. RS1-7, and Penicillium sp. HFS3-3 showed antagonistic activity against the four phytopathogenic Fusarium strains Fusarium oxysporum, Fusarium sambucinum, Fusarium fujikuroi and Fusarium incarnatum-equiseti and also a high and diverse production of enzymatic and plant growth promoting activities; here we identified fungal strains as candidates to promote maize growth.

Tools and challenges to exploit microbial communities in agriculture.

Plants contain diverse microbial communities. The associated microorganisms confer advantages to the host plant, which include growth promotion, nutrient absorption, stress tolerance, and pathogen and disease resistance. In this review, we explore how agriculture is implementing the use of microbial inoculants (single species or consortia) to improve crop yields, and discuss current strategies to study plant-associated microorganisms and how their diversity varies under unconventional agriculture. It is predicted that microbial inoculation will continue to be used in agriculture.

The Mexican giant maize of Jala landrace harbour plant-growth-promoting rhizospheric and endophytic bacteria.

The giant landrace of maize Jala is a native crop cultured in Nayarit and Jalisco States in the occident of México. In this study, after screening 374 rhizospheric and endophytic bacteria isolated from rhizospheric soil, root, and seed tissues of maize Jala, a total of 16 bacterial strains were selected for their plant-growth-promoting potential and identified by 16S rRNA phylogenetic analysis. The isolates exhibited different combinations of phenotypic traits, including solubilisation of phosphate from hydroxyapatite, production of a broad spectrum of siderophores such as cobalt, iron, molybdenum, vanadium, or zinc (Co2+, Fe3+, Mo2 +, V5+, Zn2+), and nitrogen fixation capabilities, which were detected in both rhizospheric and endophytic strains. Additional traits such as production of 1-aminocyclopropane-1-carboxylate deaminase and a high-rate production of Indoleacetic Acid were exclusively detected on endophytic isolates. Among the selected strains, the rhizospheric Burkholderia sp., and Klebsiella variicola, and the endophytic Pseudomonas protegens significantly improved the growth of maize plants in greenhouse assays and controlled the infection against Fusarium sp. 50 on fresh maize cobs. These results present the first deep approach on handling autochthonous microorganisms from native maize with a potential biotechnological application in sustainable agriculture as biofertilizers or biopesticides.

Two-Step Triethylamine-Based Synthesis of MgO Nanoparticles and Their Antibacterial Effect against Pathogenic Bacteria.

Magnesium oxide nanoparticles (MgO NPs) were obtained by the calcination of precursor microparticles (PM) synthesized by a novel triethylamine-based precipitation method. Scanning electron microscopy (SEM) revealed a mean size of 120 nm for the MgO NPs. The results of the characterizations for MgO NPs support the suggestion that our material has the capacity to attack, and have an antibacterial effect against, Gram-negative and Gram-positive bacteria strains. The ability of the MgO NPs to produce reactive oxygen species (ROS), such as superoxide anion radicals (O2•-) or hydrogen peroxide (H2O2), was demonstrated by the corresponding quantitative assays. The MgO antibacterial activity was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, with minimum inhibitory concentrations (MICs) of 250 and 500 ppm on the microdilution assays, respectively. Structural changes in the bacteria, such as membrane collapse; surface changes, such as vesicular formation; and changes in the longitudinal and horizontal sizes, as well as the circumference, were observed using atomic force microscopy (AFM). The lipidic peroxidation of the bacterial membranes was quantified, and finally, a bactericidal mechanism for the MgO NPs was also proposed.

Bacterial Succession through the Artisanal Process and Seasonal Effects Defining Bacterial Communities of Raw-Milk Adobera Cheese Revealed by High Throughput DNA Sequencing.

The bacterial community of the artisanal Adobera cheese from Los Altos de Jalisco was described through high-throughput sequencing of 16S rRNA gene libraries. Samples were collected in two different seasons (dry and rainy) during four key steps of the manufacturing process (raw milk, fresh curd, matured curd, and cheese). Bacterial diversity was higher in early steps in comparison with the final elaboration stages. Firmicutes and Proteobacteria were the most abundant phyla, strongly represented by the Streptococcaceae, Enterobacteriaceae and Lactobacillaceae families, and core bacteria genera such as Streptococcus spp., Lactococcus spp., and Lactobacillus spp. Undesirable bacteria, including Pseudomonas spp. and Acinetobacter spp., were also detected in raw milk but almost undetectable at the end of the cheese manufacturing process, and seemed to be displaced by lactic-acid bacteria-related genera. Seasonal effects were observed on the community structure but did not define the core microbiota composition. Predictive metabolism was related to membrane transport, and amino-acid, lipid, and carbohydrate metabolism pathways. Our results contribute to deduce the role of bacteria involved in Adobera cheese manufacturing in terms of the metabolism involved, cheese microbial safety, and how undesirable bacterial populations could be regulated by process standardization as a potential tool to improve safety.

The Bacterial Community Associated with the Amarillo Zamorano Maize (Zea mays) Landrace Silage Process.

Maize silage is used in the diet of dairy cows, with suitable results in milk yield. In this study, the composition and diversity of the bacterial communities of the silage process of Amarillo Zamorano (AZ) Mexican maize landrace with relation to the Antilope (A) commercial hybrid are described. From both types of maize, seeds were sown in experimental plots, plants harvested at the reproductive stage, chopped, and packed in laboratory micro-silos. Physicochemical parameters were evaluated, and DNA was extracted from the juice in the micro-silos. The bacterial communities were analyzed by next-generation sequencing (NGS) of seven hypervariable regions of the 16S rRNA gene. The composition of both bacterial communities was dominated by Lactobacillales and Enterobacteriales, Lactobacillales mainly in A silage and Enterobacteriales in AZ silage; as well, the core bacterial community of both silages comprises 212 operational taxonomic units (OTUs). Sugar concentration showed the highest number of significant associations with OTUs of different phyla. The structure of the bacterial communities was different in both silage fermentation processes, showing that AZ silage has a shorter fermentation process than A silage. In addition, NGS demonstrated the effect of the type of maize and local conditions on silage fermentation and contributed to potential strategies to improve the quality of AZ silage.

Cell vacuolation induced by Haemophilus influenzae supernatants in HEp-2 cells.

Haemophilus influenzae belongs to respiratory tract microbiota. We observed vacuoles formation in previous studies with H. influenzae culture supernatants, so in this work we characterised that cytotoxic effect. We observed an abundant production of acidic cytoplasmic vacuoles due to the presence of a "vacuolating factor" in H. influenzae supernatants which was characterised as thermolabile. Greatest vacuolating activity was observed when utilizing the fraction > 50 kDa. The presence of a large number of vacuoles in HEp-2 cells was verified by transmission electron microscopy and some vacuoles were identified with a double membrane and/or being surrounded by ribosomes. These results suggest similar behaviour to that of vacuolating effects described by autotransporter proteins an undescribed cytotoxic effect induced by H. influenzae.

Serogroups, K1 antigen, and antimicrobial resistance patterns of Aeromonas spp. strains isolated from different sources in Mexico

A total of 221 strains of Aeromonas species isolated in Mexico from clinical (161), environmental (40), and food (20) samples were identified using the automated system bioMérieux-Vitek®. Antisera for serogroups O1 to 044 were tested using the Shimada and Sakazaki scheme. The K1 antigen was examined using as antiserum the O7:K1C of Escherichia coli. Besides, we studied the antimicrobial patterns according to Vitek AutoMicrobic system. Among the 161 clinical strains 60 percent were identified as A. hydrophila, 20.4 percent as A. caviae, and 19.25 percent as A. veronii biovar sobria. Only A. hydrophila and A. veronii biovar sobria were found in food (55 and 90 percent respectively) and environmental sources (45 and 10 percent respectively). Using "O" antisera, only 42.5 percent (94/221) of the strains were serologically identified, 55 percent (121/221) were non-typable, and 2.5 percent (6/221) were rough strains. Twenty-two different serogroups were found, O14, O16, O19, O22, and O34 represented 60 percent of the serotyped strains. More than 50 percent of Aeromonas strain examined (112/221) expressed K1 encapsulating antigen; this characteristic was predominant among Aeromonas strains of clinical origin. Resistance to ampicillin/sulbactam and cephazolin was detected in 100 and 67 percent of Aeromonas strain tested for their susceptibility to antibiotics. In conclusion, antibiotic-resistant Aeromonas species that possess the K1 encapsulating antigen and represent serogroups associated with clinical syndrome in man are not uncommon among Aeromonas strains isolated from clinical, food and environmental sources in Mexico.