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1.
J Biosci ; 492024.
Article in English | MEDLINE | ID: mdl-39402958

ABSTRACT

Peanut is susceptible to many diseases; among them, peanut smut disease caused by Thecaphora frezzii is the most damaging, causing yield losses of 30%. Fungicide treatment is not effective to control this disease. In this scenario, biological control would be an alternative to diminish the disease. Systemic resistance induced by a biotic agent is known to be effective against a broad spectrum of pathogens. In this study we evaluated the effect of different inoculation strategies of Bacillus sp. CHEP5, a peanut native strain, on peanut smut incidence and severity in field experiments. Peroxidase activity and accumulation of phenolic compounds were measured as changes associated with induced defensive traits. After three consecutive field trials, we found that Bacillus sp. CHEP5 inoculation protects peanut from T. frezzii because incidence and severity were reduced in two field trials. Furthermore, bacterial inoculation in the furrow followed by foliar application around the date of peg development would be the best strategy to control the disease. In addition, a correlation was found between increase in plant phenolic content and decrease in smut disease parameters. Thereafter, we concluded that Bacillus sp. CHEP5 may reduce smut as a result of plant defence response induction.


Subject(s)
Arachis , Bacillus , Disease Resistance , Plant Diseases , Bacillus/physiology , Plant Diseases/microbiology , Plant Diseases/prevention & control , Arachis/microbiology , Disease Resistance/drug effects , Phenols/metabolism
2.
An Acad Bras Cienc ; 96(suppl 1): e20230924, 2024.
Article in English | MEDLINE | ID: mdl-39319833

ABSTRACT

The cultivation of marine shrimp is one of the fastest growing activities in the world. However, the emergence of diseases has resulted in a decrease in production and losses for the sector. Probiotics emerged as an option to the use of antibiotics to control these pathogens. The efficiency of applying this technology depends on the characteristics of the bacterial agents and their bioavailability in the shrimp intestine. The objective is to evaluate the viability and efficiency of bacteria isolated from the digestive tract of healthy crustaceans as probiotic agents in the cultivation of shrimp Litopenaeus vannamei. Eighteen strains of the genus Bacillus belonging to the following species were tested: Bacillus sp., B. cereus, B. thuringiensis, B. circulans, B. megaterium, B. subtilis and B. agaridevorans. Bacterial isolates were subjected to characterization as potential probiotics. The test results were considered satisfactory; thus, the tested strains have potential for use as probiotics in shrimp culture. Treatments that used of the genus Bacillus had reduced growth of the genus Vibrio after infection, both in the intestinal contents and in the intestine. With the results obtained, it can be suggested that further research be carried out on the probiotic potential of Bacillus sp.


Subject(s)
Bacillus , Gastrointestinal Tract , Probiotics , Animals , Bacillus/physiology , Bacillus/classification , Bacillus/isolation & purification , Gastrointestinal Tract/microbiology , Penaeidae/microbiology , Vibrio/physiology
3.
Curr Microbiol ; 81(10): 339, 2024 Sep 03.
Article in English | MEDLINE | ID: mdl-39225833

ABSTRACT

Bacterial spores in materials and equipment pose significant biosecurity risks, making effective disinfection crucial. This study evaluated Ortho-phthalaldehyde (OPA) and a quaternary ammonia-glutaraldehyde solution (AG) for inactivating spores of Bacillus thuringiensis (BT), B. cereus (BC), and two strains of B. velezensis (BV1 and BV2). Spores of BV1 and BT were treated with 22.5 mg/m3 OPA by dry fumigation or 1 mg/mL AG by spray for 20 min, according to the manufacturer's recommendation. As no sporicidal effect was observed, OPA was tested at 112.5 mg/m3 for 40 min, showing effectiveness for BT but not for BV1. Minimum bactericidal concentration (MBC) tests revealed higher MBC values for glutaraldehyde, prompting an overnight test with 112.5 mg/m3 OPA by dry fumigation and 50 mg/mL AG by spray, using formaldehyde as a control. AG reduced all Bacillus strains, but with limited sporicidal effect. OPA was sporicidal for BT and BV1 but not for BC and BV2, indicating a strain-dependent effect. Formaldehyde performed better overall but did not completely inactivate BV2 spores. Our findings suggest that OPA and AG have potential as formaldehyde replacements in wet disinfection procedures.


Subject(s)
Bacillus thuringiensis , Bacillus , Disinfectants , Glutaral , Spores, Bacterial , Disinfectants/pharmacology , Spores, Bacterial/drug effects , Bacillus/drug effects , Bacillus/physiology , Glutaral/pharmacology , Bacillus thuringiensis/drug effects , Bacillus thuringiensis/physiology , Microbial Sensitivity Tests , o-Phthalaldehyde/pharmacology , Bacillus cereus/drug effects , Microbial Viability/drug effects , Disinfection/methods
4.
Sci Rep ; 14(1): 15383, 2024 07 04.
Article in English | MEDLINE | ID: mdl-38965309

ABSTRACT

The drought can cause a decrease in food production and loss of biodiversity. In northern Mexico, an arid region, the chiltepin grows as a semi-domesticated crop that has been affected in its productivity and yield. An alternative to mitigate the effect of drought and aid in its conservation could be using Plant Growth-Promoting Bacteria (PGPB). The present study evaluated the capacity of native Bacillus spp., isolated from arid soils, as PGPBs and drought stress tolerance inducers in chiltepin under controlled conditions. Chiltepin seeds and seedlings were inoculated with native strains of Bacillus spp. isolated from arid soils, evaluating germination, vegetative, and drought stress tolerance parameters. The PGPBs improved vegetative parameters such as height, stem diameter, root length, and slenderness index in vitro. B. cereus (Bc25-7) improved in vitro survival of stressed seedlings by 68% at -1.02 MPa. Under greenhouse conditions, seedlings treated with PGPBs exhibited increases in root length (9.6%), stem diameter (13.68%), leaf fresh weight (69.87%), and chlorophyll content (38.15%). Bc25-7 alleviated severe water stress symptoms (7 days of water retention stress), and isolates B. thuringiensis (Bt24-4) and B. cereus (Bc25-7, and Bc30-2) increased Relative Water Content (RWC) by 51%. Additionally, the treated seeds showed improved germination parameters with a 46.42% increase in Germination Rate (GR). These findings suggest that using PGPBs could be an alternative to mitigate the effect of drought on chiltepin.


Subject(s)
Bacillus , Capsicum , Droughts , Seedlings , Capsicum/growth & development , Capsicum/microbiology , Capsicum/physiology , Bacillus/physiology , Seedlings/growth & development , Seedlings/microbiology , Stress, Physiological , Germination , Seeds/growth & development , Seeds/microbiology , Soil Microbiology , Plant Roots/microbiology , Plant Roots/growth & development , Mexico
5.
Microb Ecol ; 87(1): 76, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38801423

ABSTRACT

Modern crop production relies on the application of chemical pesticides and fertilizers causing environmental and economic challenges. In response, less environmentally impactful alternatives have emerged such as the use of beneficial microorganisms. These microorganisms, particularly plant growth-promoting bacteria (PGPB), have demonstrated their ability to enhance plant growth, protect against various stresses, and reduce the need for chemical inputs. Among the PGPB, Bacillus species have garnered attention due to their adaptability and commercial potential. Recent reports have highlighted Bacillus strains as biocontrol agents against phytopathogenic bacteria while concurrently promoting plant growth. We also examined Bacillus plant growth-promoting abilities in Arabidopsis thaliana seedlings. In this study, we assessed the potential of various Bacillus strains to control diverse phytopathogenic bacteria and inhibit quorum sensing using Chromobacterium violaceum as a model system. In conclusion, our results suggest that bacteria of the genus Bacillus hold significant potential for biotechnological applications. This includes developments aimed at reducing agrochemical use, promoting sustainable agriculture, and enhancing crop yield and protection.


Subject(s)
Arabidopsis , Bacillus , Plant Diseases , Bacillus/physiology , Arabidopsis/microbiology , Arabidopsis/growth & development , Plant Diseases/prevention & control , Plant Diseases/microbiology , Quorum Sensing , Chromobacterium/physiology , Chromobacterium/growth & development , Biological Control Agents/pharmacology , Plant Development , Seedlings/microbiology , Seedlings/growth & development , Soil Microbiology
6.
Braz J Microbiol ; 55(2): 1883-1896, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38609692

ABSTRACT

BACKGROUND: Biocontrol is regarded as a viable alternate technique for managing sugarcane wilt disease caused by Fusarium sacchari. Many fungal antagonists against F. sacchari, have been reported, but the potential of bacterial antagonists was explored to a limited extent, so the present study evaluated the antagonistic potential of rhizoplane Bacillus species and their mode of action. RESULTS: A total of twenty Bacillus isolates from the rhizoplane of commercially grown sugarcane varieties were isolated. The potential isolate SRB2 had shown inhibition of 52.30, 33.33, & 44.44% and SRB20 of 35.00, 33.15, & 36.85% in direct, indirect, and remote confrontation respectively against F. sacchari. The effective strains were identified as Bacillus inaquosorum strain SRB2 and B. vallismortis strain SRB20, by PCR amplification of 16S-23S intergenic region. The biochemical studies on various direct and indirect biocontrol mechanisms revealed the production of IAA, Protease, Cellulase, Siderophores, and P solubilization. The molecular analysis revealed the presence of antimicrobial peptides biosynthetic genes like fenD (Fengycin), bmyB (Bacyllomicin) ituC (Iturin) and spaS (Subtilin) which provided a competitive edge to these isolates compared to other Bacillus strains. Under greenhouse experiments, the sett bacterization with SRB2, significantly (P < 0.001) reduced the seedling mortality by > 70% followed by SRB20 in F. sacchari inoculated pots. CONCLUSION: The study revealed that the isolates B. inaquosorum SRB2 and B. vallismortis SRB20 can be used as potential bioagents against sugarcane Fusarium wilt.


Subject(s)
Bacillus , Fusarium , Plant Diseases , Saccharum , Saccharum/microbiology , Fusarium/genetics , Fusarium/physiology , Bacillus/genetics , Bacillus/physiology , Bacillus/metabolism , Bacillus/isolation & purification , Bacillus/classification , Plant Diseases/microbiology , Plant Diseases/prevention & control , Antibiosis , Biological Control Agents , Phylogeny , Rhizosphere , Soil Microbiology
7.
Biotechnol Adv ; 70: 108303, 2024.
Article in English | MEDLINE | ID: mdl-38128850

ABSTRACT

Soil salinity is one of the most important abiotic factors that affects agricultural production worldwide. Because of saline stress, plants face physiological changes that have negative impacts on the various stages of their development, so the employment of plant growth-promoting bacteria (PGPB) is one effective means to reduce such toxic effects. Bacteria of the Bacillus genus are excellent PGPB and have been extensively studied, but what traits makes them so extraordinary to adapt and survive under harsh situations? In this work we review the Bacillus' innate abilities to survive in saline stressful soils, such as the production osmoprotectant compounds, antioxidant enzymes, exopolysaccharides, and the modification of their membrane lipids. Other survival abilities are also discussed, such as sporulation or a reduced growth state under the scope of a functional interaction in the rhizosphere. Thus, the most recent evidence shows that these saline adaptive activities are important in plant-associated bacteria to potentially protect, direct and indirect plant growth-stimulating activities. Additionally, recent advances on the mechanisms used by Bacillus spp. to improve the growth of plants under saline stress are addressed, including genomic and transcriptomic explorations. Finally, characterization and selection of Bacillus strains with efficient survival strategies are key factors in ameliorating saline problems in agricultural production.


Subject(s)
Bacillus , Bacillus/physiology , Soil , Plant Roots/microbiology , Bacteria/genetics , Antioxidants
8.
Int. j. morphol ; 41(1): 286-296, feb. 2023. ilus, tab, graf
Article in English | LILACS | ID: biblio-1430539

ABSTRACT

SUMMARY: Cancer is the second leading cause of death in the world and colorectal cancer is the only cancer that has shown a sustained increase in mortality in the last decade. In the search for new chemotherapeutic agents against cancer, extremophilic microorganisms have shown to be a potential source to obtain molecules of natural origin and with selective cytotoxic action towards cancer cells. In this work we analyzed the ability of a collection of Antarctic soil bacteria, isolated on Collins Glacier from the rhizosphere of Deschampsia antarctica Desv plant, to secrete molecules capable of inhibiting cell proliferation of a colorectal cancer tumor line. Our results demonstrated that culture supernatants from the Antarctic bacteria K2I17 and MI12 decreased the viability of LoVo cells, a colorectal adenocarcinoma cell line. Phenotypic and genotypic characterization of the Antarctic bacteria showed that they were taxonomically related and nucleotide identity analysis based on the 16S rRNA gene sequence identified the bacterium K2I17 as a species belonging to the genus Bacillus.


El cáncer es la segunda causa de muerte en el mundo y el cáncer colorrectal es el único que presenta un aumento sostenido de la mortalidad en la última década. En la búsqueda de nuevos agentes quimioterapeúticos contra el cáncer, se ha propuesto a los microorganismos extremófilos como una fuente potencial para obtener moléculas de origen natural y con acción citotóxica selectiva hacia las células cancerígenas. En este trabajo analizamos la capacidad de una colección de bacterias de suelo antártico, aisladas en el glaciar Collins desde rizosfera de la planta de Deschampsia antarctica Desv, de secretar moléculas capaces de inhibir la proliferación celular de una línea tumoral de cáncer colorrectal. Nuestros resultados demostraron que los sobrenadantes de cultivo de las bacterias antárticas K2I17 y MI12 disminuyeron la viabilidad de la línea celular de adenocarcinoma colorrectal LoVo, en un ensayo de reducción metabólica de MTT. La caracterización fenotípica y genotípica de las bacterias antárticas, demostró que estaban relacionadas taxonómicamente y el análisis de la identidad nucleotídica en base a la secuencia del gen ARNr 16S identificó a la bacteria K2I17 como una especie perteneciente al género Bacillus.


Subject(s)
Humans , Soil Microbiology , Bacillus/physiology , Colorectal Neoplasms/drug therapy , Cell Proliferation/drug effects , Phenotype , Bacillus/isolation & purification , Bacillus/genetics , In Vitro Techniques , RNA, Ribosomal, 16S , Adenocarcinoma/drug therapy , Cell Survival/drug effects , Polymerase Chain Reaction , Cell Line, Tumor/drug effects , Genotype , Antarctic Regions
9.
World J Microbiol Biotechnol ; 38(3): 53, 2022 Feb 10.
Article in English | MEDLINE | ID: mdl-35141795

ABSTRACT

Citrus fruits are the most produced fruits in the world, but they are threatened by several pathogens, including the fungus Phyllosticta citricarpa, the causal agent of citrus black spot (CBS). The fungus affects most citrus species and the infection results in economic losses in citrus-producing areas. This disease causes the aesthetic depreciation of fresh fruit, impairing its commercialization. As an alternative to the use of synthetic fungicides to control the pathogen, the biological control, using bacteria of the genus Bacillus, is highlighted. Such microorganisms enable biocontrol by the production of volatile organic compounds (VOC) or non-volatile. Therefore, this work aimed to evaluate the production of VOC by isolates of Bacillus spp. grown in different culture media; to evaluate the effects of these compounds on the evolution of CBS lesions in orange fruits; to study the effects of VOC on resistance induction in orange fruits; to evaluate the effects of VOC on P. citricarpa morphology in CBS lesions, and to identify the produced VOC. Tryptone soya agar (TSA) and tryptone soya broth (TSB) media used to culture the bacterium resulted in up to 73% pathogen inhibition by VOC. Volatile compounds from Bacillus spp. ACB-65 and Bacillus spp. ACB-73 when cultured in TSB culture medium provided 86% inhibition of freckles that evolved to hard spots. The volatile fractions produced by the bacteria were identified as alcohols, ketones, amines, ethers, aldehydes and carboxylic acids that can serve as arsenal against the phytopathogen. The present work demonstrated the potential of VOC produced by Bacillus spp. in the control of P. citricarpa.


Subject(s)
Ascomycota/pathogenicity , Bacillus , Biological Control Agents , Citrus , Plant Diseases/prevention & control , Bacillus/physiology , Citrus/microbiology , Microbial Interactions , Plant Diseases/microbiology , Spores, Fungal
10.
Microbiol Res ; 248: 126754, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33848783

ABSTRACT

Endophytic bacteria show important abilities in promoting plant growth and suppressing phytopathogens, being largely explored in agriculture as biofertilizers or biocontrol agents. Bacteria from canola roots were isolated and screened for different plant growth promotion (PGP) traits and biocontrol of Sclerotinia sclerotiorum. Thirty isolates belonging to Bacillus, Paenibacillus, Lysinibacillus, and Microbacterium genera were obtained. Several isolates produced auxin, siderophores, hydrolytic enzymes, fixed nitrogen and solubilized phosphate. Five isolates presented antifungal activity against S. sclerotiorum by the dual culture assay and four of them also inhibited fungal growth by volatile organic compounds production. All antagonistic isolates belonged to the Bacillus genus, and had their genomes sequenced for the search of biosynthetic gene clusters (BGC) related to antimicrobial metabolites. These isolates were identified as Bacillus safensis (3), Bacillus pumilus (1), and Bacillus megaterium (1), using the genomic metrics ANI and dDDH. Most strains showed several common BGCs, including bacteriocin, polyketide synthase (PKS), and non-ribosomal peptide synthetase (NRPS), related to pumilacidin, bacillibactin, bacilysin, and other antimicrobial compounds. Pumilacidin-related mass peaks were detected in acid precipitation extracts through MALDI-TOF analysis. The genomic features demonstrated the potential of these isolates in the suppression of plant pathogens; however, some aspects of plant-bacterial interactions remain to be elucidated.


Subject(s)
Antibiosis , Ascomycota/growth & development , Bacillus/physiology , Brassica napus/microbiology , Endophytes/physiology , Plant Diseases/prevention & control , Ascomycota/metabolism , Bacillus/classification , Bacillus/genetics , Bacillus/isolation & purification , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Brassica napus/growth & development , Endophytes/classification , Endophytes/genetics , Endophytes/isolation & purification , Plant Diseases/microbiology , Plant Roots/growth & development , Plant Roots/microbiology
11.
Braz J Microbiol ; 52(2): 705-714, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33594600

ABSTRACT

Fungal pathogens are important determinants of plant dynamics in the environment. These pathogens can cause plant death and occasionally yield losses in crops, even at low initial densities in the soil. The objective of this study was to select and evaluate fungal antagonistic bacteria and to determine their biological control capacity in soybean seedlings. A total of 877 strains from the genera Pseudomonas, Bacillus, and Paraburkholderia/Burkholderia were screened, and their antagonistic effects on fungi frequently found in seeds were evaluated using four methods: quadruple plating, paired culture confrontation, strain containment, and inoculation of soybean seeds. The experimental design was completely randomized, with three replications for the first three methods and five replications in a 3 × 9 factorial scheme for the fourth treatment. The strains with the highest biotechnological potential were inoculated into soybean seeds to evaluate the biological control of fungi that attack this crop at germination. Seventy-nine strains presented some type of antagonistic effect on the tested fungi, with two strains presenting a broader antagonistic action spectrum in the seed test. In addition to the antagonistic potential, strains BR 10788 and BR 11793, when simultaneously inoculated or alone, significantly increased the seedling dry matter mass, and promoted the growth of soybean seedlings even in the presence of most fungi. Thus, this study demonstrated the efficiency of the antagonistic activity of these strains in relation to the target fungi, which proved to be potential agents for biological control.


Subject(s)
Antibiosis , Bacillus/physiology , Plant Diseases/prevention & control , Pseudomonas/physiology , Seeds/microbiology , Bacillus/classification , Fungi/physiology , Plant Diseases/microbiology , Pseudomonas/classification , Seedlings/growth & development , Seedlings/microbiology , Seeds/growth & development , Glycine max/growth & development , Glycine max/microbiology
12.
World J Microbiol Biotechnol ; 37(2): 28, 2021 Jan 13.
Article in English | MEDLINE | ID: mdl-33439401

ABSTRACT

Aquaculture is one of the fastest-growing economic activities worldwide; shrimp production by aquaculture is around 70% or more of the total consumed. The development of this activity is inducing great benefits in the production of food and jobs; however, shrimp aquaculture is also generating; (1) ecological imbalance by pelagic species overexploitation to produce fish ingredients, (2) bays contamination by inappropriate waste management and (3) pathogens proliferation by antibiotics abuse. In this sense, a significant number of regulations and legal restrictions have been imposed; thus, aquaculture is no longer considered a profitable activity. Therefore, significant and innovative technologies need to be applied to ensure the sustainability and profitability of this activity. In this sense, probiotic bacteria are being used in aquaculture to improve feed intake, modulate gut microbiota and control pathogen proliferation. This work summarizes the results from researchers who worked extensively to show how probiotic bacteria can improve shrimp aquaculture development.


Subject(s)
Animal Diseases/prevention & control , Bacillus/physiology , Eating , Gastrointestinal Microbiome/physiology , Penaeidae/microbiology , Animal Feed , Animals , Aquaculture/methods , Bacteria , Bacterial Infections/prevention & control , Bacterial Infections/veterinary , Penaeidae/growth & development , Probiotics/administration & dosage , Seafood , Vegetables
13.
Genomics ; 112(6): 4525-4535, 2020 11.
Article in English | MEDLINE | ID: mdl-32781202

ABSTRACT

Bacillus sp. SFC 500-1E is used for the effective treatment of tannery effluents since it consistently removes hexavalent chromium from diverse contaminated matrices. The aim of the present study was to complete identification of the strain through a polyphasic characterization, which included the pattern of carbohydrate utilization, fatty acids profile, multilocus sequence analysis, multiplex PCR profile and the analysis of the complete genome sequence. Morpho-physiological and biochemical characterization results and analysis of 16S rRNA sequences were not conclusive. The strain formed a monophyletic clade with B. toyonensis BCT-7112, B. thuringiensis MC28 and B. cereus Rock 1-3. However, genomic comparisons with type strains of B. cereus and B. thuringiensis showed that the isolated belonged to a different species. Results of this study highlight the relevance of the genome sequence of this strain, identified as Bacillus toyonensis SFC 500-1E, to expand knowledge of its bioremediation potential and to explore unknown decontamination activities.


Subject(s)
Bacillus/classification , Bacillus/cytology , Bacillus/genetics , Bacillus/physiology , Bacillus cereus/classification , Biodegradation, Environmental , Genome, Bacterial , Genomics , Phylogeny , RNA, Ribosomal, 16S/genetics
15.
J Biosci ; 452020.
Article in English | MEDLINE | ID: mdl-32385221

ABSTRACT

microRNAs (miRNAs) are non-coding small RNAs that regulate gene expression at post-transcriptional level. Thousands of miRNAs have been identified in legumes, but studies about miRNAs linked to peanut nodule functionality are scarce. In this work we analyzed transcriptional changes in peanut nodules to identify miRNAs involved in functional processes of these organs. We found 32 miRNAs precursors differentially expressed in nodules compared with roots, and predicted the potential targets of their corresponding mature miRNAs. Among them, 20 belong to 14 conserved miRNAs families and 12 are Arachis hypogaea-specific miRNAs. Expression levels of 3 miRNAs (ahy-miR399, ahy-miR159 and ahy-miR3508) were confirmed experimentally by qPCR. We also demonstrated that the expression of these miRNAs was not affected by inoculation of a biocontrol bacterium or a fungal pathogen. The catalogue of differentially expressed miRNA precursors and the expression of the corresponding mature miRNA potential targets in the nodules of A. hypogaea obtained in this work is a database of strong candidates, including A. hypogaea-specific miRNAs, for the regulation of the nodule functionality. The analysis of their role in this process will certainly lead to the characterization of essential regulators in these particular aeschynomenoid nodules.


Subject(s)
Arachis/genetics , Gene Expression Regulation, Plant , MicroRNAs/genetics , RNA Precursors/genetics , RNA, Plant/genetics , Root Nodules, Plant/genetics , Arachis/metabolism , Arachis/microbiology , Bacillus/physiology , Bradyrhizobium/physiology , Computational Biology/methods , Gene Expression Profiling , MicroRNAs/classification , MicroRNAs/metabolism , RNA Precursors/classification , RNA Precursors/metabolism , RNA, Plant/classification , RNA, Plant/metabolism , Root Nodules, Plant/metabolism , Root Nodules, Plant/microbiology , Symbiosis/physiology , Transcriptome
16.
J Sci Food Agric ; 100(10): 4049-4056, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32338377

ABSTRACT

BACKGROUND: Avocado is affected by Colletotrichum gloeosporioides causing anthracnose. Antagonistic microorganisms against C. gloeosporioides represent an alternative for biological control. Accordingly, in the present study, we focused on the isolation and characterization of potential antagonist bacteria against a member of the C. gloeosporioides species complex with respect to their possible future application. RESULTS: Samples of avocado rhizospheric soil were aquired from an orchard located in Ocuituco, Morelos, Mexico, aiming to obtain bacterial isolates with potential antifungal activity. From the soil samples, 136 bacteria were isolated and they were then challenged against a member of the C. gloeosporioides species complex; only three bacterial isolates A1, A2 and A3 significantly diminished mycelial fungal growth by 75%, 70% and 60%, respectively. Two of these isolates were identified by 16S rRNA as Bacillus mycoides (A1 and A2) and the third was identified as Bacillus tequilensis (A3). Bacillus mycoides bacterial cell-free supernatant reduced the mycelial growth of a member of the C. gloeosporioides species complex isolated from avocado by 65%, whereas Bacillus tequilensis A3 supernatant did so by 25% after 3 days post inoculation. Bacillus tequilensis mycoides A1 was a producer of proteases, indolacetic acid and siderophores. Preventive treatment using a cell-free supernatant of B. mycoides A1 diminished the severity of anthracnose disease (41.9%) on avocado fruit. CONCLUSION: These results reveal the possibility of using B. mycoides A1 as a potential biological control agent. © 2020 Society of Chemical Industry.


Subject(s)
Antibiosis , Bacillus/physiology , Colletotrichum/growth & development , Persea/microbiology , Plant Diseases/microbiology , Bacillus/genetics , Bacillus/isolation & purification , Colletotrichum/physiology , Mexico , Mycelium/growth & development , Persea/growth & development , Siderophores/metabolism , Soil Microbiology
17.
J Bacteriol ; 202(10)2020 04 27.
Article in English | MEDLINE | ID: mdl-32071096

ABSTRACT

In bacterial populations, quorum sensing (QS) systems participate in the regulation of specialization processes and regulate collective behaviors that mediate interactions and allow survival of the species. In Gram-positive bacteria, QS systems of the RRNPP family (Rgg, Rap, NprR, PlcR, and PrgX) consist of intracellular receptors and their cognate signaling peptides. Two of these receptors, Rap and NprR, have regained attention in Bacillus subtilis and the Bacillus cereus group. Some Rap proteins, such as RapH and Rap60, are multifunctional and/or redundant in function, linking the specialization processes of sporulation and competence, as well as global expression changes in the transition phase in B. subtilis NprR, an evolutionary intermediate between Rap and RRNPP transcriptional activators, is a bifunctional regulator that modulates sporulation initiation and activates nutrient scavenging genes. In this review, we discuss how these receptors switch between functions and connect distinct signaling pathways. Based on structural evidence, we propose that RapH and Rap60 should be considered moonlighting proteins. Additionally, we analyze an evolutionary and ecological perspective to understand the multifunctionality and functional redundancy of these regulators in both Bacillus spp. and non-Bacillus Firmicutes Understanding the mechanistic, structural, ecological, and evolutionary basis for the multifunctionality and redundancy of these QS systems is a key step for achieving the development of innovative technologies for health and agriculture.


Subject(s)
Bacillus/physiology , Bacterial Proteins/metabolism , Quorum Sensing , Bacillus/genetics , Bacillus/growth & development , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Spores, Bacterial/genetics , Spores, Bacterial/growth & development , Transcription Factors/genetics , Transcription Factors/metabolism
18.
Curr Microbiol ; 77(5): 807-815, 2020 May.
Article in English | MEDLINE | ID: mdl-31925513

ABSTRACT

The search for new, powerful antimicrobials is essential to respond to the current worldwide spread of antibiotic-resistant pathogens. Sponge-associated bacteria have great potential for production of antimicrobials against resistant and multidrug resistant (MDR) pathogenic bacteria, but only few species of the Class Homoscleromorpha have been screened for these activities so far. The aim of this study was to isolate and identify sponge-associated bacteria active against antibiotic-resistant pathogens from sponges of classes Homoscleromorpha and Demospongiae. By employing five different growth conditions, a total of 239 colony-forming units were isolated and remained viable. Among these, 17 (7.1%) isolates presented antimicrobial activity against pathogenic and (multi)drug resistant bacteria including vancomycin-resistant Enterococcus faecalis, Escherichia coli, Citrobacter freundii, Klebsiella penumoniae, Staphylococcus spp. and Streptococcus spp. Bioactive bacteria belonging to genera Bacillus and Vibrio were identified at species level and the DNA fingerprint patterns showed that strains of the same genus were not clonally related. The most active strains belong to genus Bacillus and were isolated from Oscarella sp., Plakina cyanorosea and Chondrilla caribensis. Our results show for the first time that sponge-associated strains of Bacillus pumilus and Bacillus muralis have high anti-MDR activity, and that the Homoscleromorpha may be a better source of such anti-MDR active bacteria than the Demospongiae. These results suggest that marine bacteria associated to homoscleromorph sponges may be an interesting source of new antimicrobial substances with biotechnological potential to treat infections caused by antibiotic-resistant bacteria.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antibiosis , Bacillus/physiology , Bacteria/drug effects , Drug Resistance, Multiple, Bacterial , Porifera/microbiology , Animals , Bacillus/classification , Microbial Sensitivity Tests , RNA, Ribosomal, 16S/genetics
20.
Food Res Int ; 125: 108542, 2019 11.
Article in English | MEDLINE | ID: mdl-31554104

ABSTRACT

The resistance of Bifidobacterium, Lactobacillus, and Bacillus strains with claimed probiotic properties in different food matrices was evaluated. Lactobacillus paracasei PXN 37, Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12, Bifidobacterium breve PXN 25, Bacillus subtilis PXN 21, Bacillus coagulans GBI30 6086 and Bacillus coagulans MTCC 5856 strains were inoculated in "requeijão cremoso" cheese, pasteurized orange juice, and bread. Further, the counts of the strains with claimed probiotic properties were determined throughout the products' shelf-life. Additionally, the survival (%), at the beginning and at the end of their shelf-life, of each strain with claimed probiotic properties inoculated in the three foods was estimated by using a static in vitro system simulating the gastric (pH 2), enteric I (pH 5) and enteric II (pH 7) phases of gastrointestinal tract (GIT). Overall, it has been found that the Bacillus strains with claimed probiotic properties showed greater viability than probiotic Bifidobacterium and Lactobacillus strains no matter the food studied. The percentage of survival of the Bacillus strains with claimed probiotic properties were always above 83%. The Bacillus strains with claimed probiotic properties were able to survive well in all the food matrices tested. Therefore, this study shows that these strains of Bacillus may comprise a feasible strategy for expanding the range of "probiotic food" choices given their high resistance to the composition of foods, manufacturing steps, and resistance to simulated GIT conditions.


Subject(s)
Bacillus/physiology , Food Microbiology , Microbial Viability , Probiotics , Bifidobacterium/physiology , Digestion/physiology , Gastrointestinal Microbiome/physiology , Humans , Hydrogen-Ion Concentration , Lactobacillus/physiology , Models, Biological
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