RESUMO
Toxic and heavy metals cause direct and indirect damage to the environment and ultimately to humans. This study involved the isolation of indigenous bacteria from heavy metal-contaminated environments that have the ability to bioabsorb heavy metals such as cadmium, nickel, and lead. The bioabsorption process was optimized by varying parameters such as temperature, metal concentration, number of bacteria, pH, and more. The bacterial isolates were investigated in terms of morphology, biochemistry, and phylogeny, with 12 strains chosen in the initial stage and one strain chosen in the final stage. It should be remembered that the metal uptake capacity of all isolates was approximately calculated. A box and reactor were designed to house these optimized microorganisms. Based on biochemical, morphological, and molecular results, the isolated strain was found to be closely related to the Bacillus genus. In the first five steps of testing, the ideal pH for removing lead alone, lead with cadmium, lead with nickel, and lead ternary (with cadmium and nickel) by Bacillus bacteria was found to be 7, 6, 5.5, and 6.5, respectively. The absorption efficiencies for single lead (unary), lead together with nickel, cadmium (binary), and ternary (lead with cadmium and nickel) were found to be 0.36, 0.25, 0.22, and 0.21 mmol/g, respectively. The ideal temperature for lead removal was around 30 °C. The adsorption isotherm for each lead metal in different states was found to be similar to the Langmuir isotherm, indicating that the surface absorption process is a single-layer process. The kinetics of the process follow the second-order kinetic model. The amount of Bacillus bacteria biomass obtained during this process was approximately 1.5 g per liter.
Assuntos
Biofilmes , Reatores Biológicos , Metais Pesados , Metais Pesados/metabolismo , Reatores Biológicos/microbiologia , Biofilmes/crescimento & desenvolvimento , Biodegradação Ambiental , Níquel/metabolismo , Níquel/química , Cádmio/metabolismo , Bacillus/metabolismo , Filogenia , Concentração de Íons de Hidrogênio , Bactérias/metabolismo , Adsorção , Chumbo/metabolismo , TemperaturaRESUMO
The use of plant growth-promoting rhizobacteria (PGPR) in agriculture is one of the most promising approaches to improve plants' growth under salt stress and to support sustainable agriculture under climate change. In this context, our goal was to grow and enhance quinoa growth using native rhizobacteria that can withstand salt stress. To achieve this objective, we isolated rhizobacteria from three saline localities in a semi-arid region in Tunisia, which are characterized by different halophyte species and tested their plant growth-promoting (PGP) activities. Then, we inoculated quinoa seedlings cultivated on 300 mM NaCl with the three most efficient rhizobacteria. A positive effect of the three-salt tolerant rhizobacteria on the growth of quinoa under salinity was observed. In fact, the results of principal component analysis indicated that the inoculation of quinoa by salt-tolerant PGPR under high salinity had a prominent beneficial effect on various growth and physiological parameters of stressed plant, such as the biomass production, the roots length, the secondary roots number, proline content and photosynthesis activities. Three rhizobacteria were utilized in this investigation, and the molecular identification revealed that strain 1 is related to the Bacillus inaquosorum species, strain 2 to Bacillus thuringiensis species and strain 3 to Bacillus proteolyticus species. We can conclude that the saline soil, especially the halophytic rhizosphere, is a potential source of salt-tolerant plant growth-promoting rhizobacteria (ST-PGPR), which stimulate the growth of quinoa and improve its tolerance to salinity.
Assuntos
Chenopodium quinoa , Raízes de Plantas , Salinidade , Tolerância ao Sal , Plantas Tolerantes a Sal , Chenopodium quinoa/fisiologia , Chenopodium quinoa/crescimento & desenvolvimento , Plantas Tolerantes a Sal/microbiologia , Plantas Tolerantes a Sal/fisiologia , Plantas Tolerantes a Sal/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Cloreto de Sódio/farmacologia , Microbiologia do Solo , Tunísia , Bacillus/fisiologia , Plântula/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/fisiologia , BiomassaRESUMO
This study investigates the efficacy of Trichoderma spp. and Bacillus spp., as well as their gamma radiation-induced mutants, as potential biological control agents against Meloidogyne javanica (Mj) in tomato plants. The research encompasses in vitro assays, greenhouse trials, and molecular identification methodologies to comprehensively evaluate the biocontrol potential of these agents. In vitro assessments reveal significant nematicidal activity, with Bacillus spp. demonstrating notable effectiveness in inhibiting nematode egg hatching (16-45%) and inducing second-stage juvenile (J2) mortality (30-46%). Greenhouse trials further confirm the efficacy of mutant isolates, particularly when combined with chitosan, in reducing nematode-induced damage to tomato plants. The combination of mutant isolates with chitosan reduces the reproduction factor (RF) of root-knot nematodes by 94%. By optimizing soil infection conditions with nematodes and modifying the application of the effective compound, the RF of nematodes decreases by 65-76%. Molecular identification identifies B. velezensis and T. harzianum as promising candidates, exhibiting significant nematicidal activity. Overall, the study underscores the potential of combined biocontrol approaches for nematode management in agricultural settings. However, further research is essential to evaluate practical applications and long-term efficacy. These findings contribute to the development of sustainable alternatives to chemical nematicides, with potential implications for agricultural practices and crop protection strategies.
Assuntos
Bacillus , Raios gama , Controle Biológico de Vetores , Doenças das Plantas , Solanum lycopersicum , Tylenchoidea , Animais , Tylenchoidea/fisiologia , Bacillus/genética , Bacillus/fisiologia , Solanum lycopersicum/parasitologia , Solanum lycopersicum/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia , Controle Biológico de Vetores/métodos , Mutação , Hypocreales/genética , Antinematódeos/farmacologia , Agentes de Controle Biológico/farmacologia , Quitosana/farmacologiaRESUMO
The escalating interest in Bacillus velezensis as a biocontrol agent arises from its demonstrated efficacy in inhibiting both phytopathogenic fungi and bacteria, positioning it as a promising candidate for biotechnological applications. This mini review aims to offer a comprehensive exploration of the multifaceted properties of B. velezensis, with particular focus on its beneficial interactions with plants and its potential for controlling phytopathogenic fungi. The molecular dialogues involving B. velezensis, plants, and phytopathogens are scrutinized to underscore the intricate mechanisms orchestrating these interactions. Additionally, the review elucidates the mode of action of B. velezensis, particularly through cyclic lipopeptides, highlighting their importance in biocontrol and promoting plant growth. The agricultural applications of B. velezensis are detailed, showcasing its role in enhancing crop health and productivity while reducing reliance on chemical pesticides. Furthermore, the review extends its purview in the industrial and environmental arenas, highlighting its versatility across various sectors. By addressing challenges such as formulation optimization and regulatory frameworks, the review aims to chart a course for the effective utilization of B. velezensis. KEY POINTS: ⢠B. velezensis fights phytopathogens, boosting biotech potential ⢠B. velezensis shapes agri-biotech future, offers sustainable solutions ⢠Explores plant-B. velezensis dialogue, lipopeptide potential showcased.
Assuntos
Bacillus , Doenças das Plantas , Bacillus/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Lipopeptídeos/metabolismo , Lipopeptídeos/farmacologia , Fungos/metabolismo , Fungos/efeitos dos fármacos , Desenvolvimento Vegetal , Controle Biológico de Vetores/métodos , Biotecnologia/métodos , Produtos Agrícolas/microbiologia , Plantas/microbiologia , Agricultura/métodosRESUMO
Biofilms are common living states for microorganisms, allowing them to adapt to environmental changes. Numerous Bacillus strains can form complex biofilms that play crucial roles in biocontrol processes. However, our current understanding of the molecular mechanisms of biofilm formation in Bacillus is mainly based on studies of Bacillus subtilis. Knowledge regarding the biofilm formation of other Bacillus species remains limited. In this study, we identified a novel transcriptional regulator, BmfR, belonging to the GntR family, that regulates biofilm formation in marine-derived Bacillus methylotrophicus B-9987. We demonstrated that BmfR induces biofilm formation by activating the extracellular polysaccharide structural genes epsA-O and negatively regulating the matrix gene repressor, SinR; of note it positively affects the expression of the master regulator of sporulation, Spo0A. Furthermore, database mining for BmfR homologs has revealed their widespread distribution among many bacterial species, mainly Firmicutes and Proteobacteria. This study advances our understanding of the biofilm regulatory network of Bacillus strains, and provides a new target for exploiting and manipulating biofilm formation.
Assuntos
Bacillus , Proteínas de Bactérias , Biofilmes , Regulação Bacteriana da Expressão Gênica , Biofilmes/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacillus/genética , Bacillus/fisiologia , Bacillus/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Polissacarídeos Bacterianos/metabolismo , Organismos Aquáticos/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismoRESUMO
Alpine meadows, which are critical for biodiversity and ecosystem services, are increasingly degrading, necessitating effective restoration strategies. This study explored the mechanism by which Kobresia humilis, an alpine meadow-constructive species, modulates the rhizosphere microbiome via root exudates to enhance growth. Field investigations revealed that the plant height of K. humilis in a severely degraded (SD) alpine meadow was significantly higher than that in other K. humilis populations. Consequently, we analysed the differences between this plot and other K. humilis samples with different degrees of degradation to explore the reasons underlying the phenotypic differences in K. humilis. 16â¯S rRNA amplicon sequencing results showed that the SD plots were significantly enriched with more Bacillus, altering the composition of the rhizosphere microbial community of K. humilis. The collection and analysis of root exudates from various K. humilis locations revealed distinct differences. Procrustes analysis indicated a strong correlation between the root exudates and the rhizosphere microbiome composition of K. humilis. Model-based integration of metabolite observations, species abundance 2 (MIMOSA2), and Spearman's rank correlation coefficient analysis were used to identify the root exudates potentially related to the enrichment and recruitment of Bacillus. Bacillus from SD samples was isolated and screened, and the representative strain D334 was found to be differentially enriched compared to other samples. A series of in vitro experiments with the screened root exudates and strain D334 demonstrated that K. humilis could recruit Bacillus and promote its colonisation by releasing flavonoids, particularly baicalin. Additionally, K. humilis can release sucrose and riboflavin, which promote strain growth. Finally, soil microbiome transplantation experiments confirmed that different K. humilis phenotypes were closely related to the functions of the rhizosphere microbiome, especially in root morphological shaping. Moreover, the effects of Bacillus inoculation and the microbiome on the plant phenotypes were consistent. In summary, this study revealed a new mechanism by which K. humilis recruits rhizosphere growth-promoting bacteria and enhances soil nutrient utilisation, thereby promoting plant growth. These findings provide a theoretical basis for ecological restoration using soil microbial communities and clarify the relationship between plant metabolites and microbial community assembly.
Assuntos
Bacillus , Flavonoides , Microbiota , Raízes de Plantas , RNA Ribossômico 16S , Rizosfera , Microbiologia do Solo , Raízes de Plantas/microbiologia , Flavonoides/metabolismo , Bacillus/metabolismo , Bacillus/genética , Bacillus/isolamento & purificação , RNA Ribossômico 16S/genética , Filogenia , Pradaria , EcossistemaRESUMO
Microbes used for the recovery of rare earth elements (REEs) from mining wastewater indicated traces of Escherichia coli (E. coli, 2149.6 µg/g), Bacillus sphaericus (1636.6 µg/g), Bacillus mycoides (1469.3 µg/g), and Bacillus cereus (1083.9 µg/g). Of these, E. coli showed an affinity for REEs than non-REEs (Mn and Zn). The amount of heavy REEs adsorbed (1511.1 µg/g) on E. coli was higher than light REEs (638.0 µg/g) due to the process of increasing adsorption with decreasing ionic radius. Additionally, E. coli demonstrated stability in the recovery of REEs from mining wastewater, as evidenced by 4 cycles. SEM-EDS, XPS and FTIR showed that REEs had a disruptive effect on cells, REEs absorbed and desorbed on the cell surface including ion exchange with ions such as Na+, ligand binding with functional groups like -NH2. Finally, the cost assessment confirmed the economically feasible of E. coli in recovery of REEs from mining wastewater.
Assuntos
Escherichia coli , Metais Terras Raras , Mineração , Águas Residuárias , Águas Residuárias/química , Bacillus/metabolismo , Adsorção , Biodegradação Ambiental , Poluentes Químicos da ÁguaRESUMO
In recent decades, probiotics have become an acceptable aquaculture strategy for shrimp growth promotion and immune modulation. This study aimed to evaluate the effect of Bacillus velezensis on Litopenaeus vannamei following a 60-day trial. L. vannamei (3 ± 0.4 g) were distributed into four groups with three replicates per group and fed an isonitrogenous diet supplemented with B. velezensis at 0, 1 × 107, 1 × 108, and 1 × 109 CFU/g, which were defined as the control, G1, G2, and G3 groups, respectively. B. velezensis significantly improved the growth, survival rate, and proximate body composition of L. vannamei (P < 0.05). All groups fed the B. velezensis diet showed significant increases in digestive enzymes (lipase, amylase, and protease), superoxide dismutase (SOD; G3), catalase (CAT; G3, G2, and G1), lysozyme activity (G3 and G2), immunoglobulin M (IgM), bactericidal activity BA%, alkaline phosphatase (AKP), and acid phosphatase (ACP) compared with the control group (P < 0.05). Malondialdehyde (MDA), triglycerides, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels were significantly decreased in all groups fed B. velezensis diet compared with the control group (P < 0.05). The expression levels of SOD (G3), LZM, and serine proteinase genes were significantly higher in L. vannamei fed diets containing B. velezensis than in the control group (P < 0.05). This is the first study to address the effects of B. velezensis on the expression of the LZM and serine proteinase genes in L. vannamei. L. vannamei fed diet containing B. velezensis had more B and R cells in its hepatopancreas than did the control group. In conclusion, B. velezensis is a promising probiotic that can be safely added to the diet of L. vannamei with 1 × 109 CFU/g. Its application had a positive influence on the health status, survival rate, nutritional value, and immunity of L. vannamei.
Assuntos
Ração Animal , Antioxidantes , Bacillus , Composição Corporal , Dieta , Penaeidae , Probióticos , Animais , Penaeidae/imunologia , Penaeidae/microbiologia , Penaeidae/crescimento & desenvolvimento , Probióticos/farmacologia , Probióticos/administração & dosagem , Dieta/veterinária , Ração Animal/análise , Antioxidantes/metabolismo , Suplementos Nutricionais , Aquicultura/métodos , Expressão GênicaRESUMO
Previous studies have demonstrated the presence of chitinase in Bacillus velezensis through extensive genomic sequencing and experimental analyses. However, the detailed structure, functional roles, and antifungal activity of these chitinases remain poorly characterized. In this study, genomic screening identified three genes-chiA, chiB, and lpmo10-associated with chitinase degradation in B. velezensis S161. These genes encode chitinases ChiA and ChiB, and lytic polysaccharide monooxygenase LPMO10. Both ChiA and ChiB contain two CBM50 binding domains and one catalytic domain, whereas LPMO10 includes a signal peptide and a single catalytic domain. The chitinases ChiA, its truncated variant ChiA2, and ChiB were heterologously expressed in Escherichia coli. The purified enzymes efficiently degraded colloidal chitin and inhibited the spore germination of Penicillium digitatum. Notably, even after losing one CBM50 domain, the resultant enzyme, consisting of the remaining CBM50 domain and the catalytic domain, maintained its colloidal chitin hydrolysis and antifungal activity, indicating commendable stability. These results underscore the role of B. velezensis chitinases in suppressing plant pathogenic fungi and provide a solid foundation for developing and applying chitinase-based biocontrol strategies.
Assuntos
Antifúngicos , Bacillus , Quitinases , Penicillium , Antifúngicos/farmacologia , Antifúngicos/química , Bacillus/enzimologia , Bacillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/farmacologia , Quitina/química , Quitinases/química , Quitinases/farmacologia , Escherichia coli , Penicillium/efeitos dos fármacos , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologiaRESUMO
OBJECTIVE: To understand the status and problems of microbial pollution in shopping malls and supermarkets in China. METHODS: Microbial pollution in shopping malls and supermarkets was assessed by literature search, key information extraction and analysis. The strengths, weaknesses, opportunities and threats(SWOT) of risk control of pathogenic microorganisms in shopping malls and supermarkets were analyzed by SWOT analysis. RESULTS: Common bacteria in the indoor air of shopping malls and supermarkets included staphylococcus and Bacillus, and common fungi include Aspergillus and Penicillium. The bacteria detected in dust samples, escalator surfaces and floor surfaces were mainly Proteobacteria and Actinomyces. The complete public places laws and regulations, standards and health supervision system were the advantages of the risk prevention and control countermeasures of microbial contamination in shopping malls and supermarkets. At the same time, it also had the disadvantages of incomplete microbial-related indexes in the premises, and insufficiently detailed countermeasures for prevention and control in the premises. There were opportunities for multi-sectoral participation and post-licensing risk prevention, and it was also facing challenges brought by many factors affecting the health microenviroment and over-disinfection. CONCLUSION: The main sites for microbial risk prevention and control in superstore-type public places included high-frequency contact areas, key public supplies and utensils, indoor air, etc. , which could be prevented and controlled through a variety of measures such as controlling the release of the source, dilution and reduction, disinfection and denaturation, etc. , and exploring a comprehensive prevention and control system that involves the autonomy of the organization, industry self-regulation, collaboration of multi-government departments, and participation of the whole society.
Assuntos
Poluição do Ar em Ambientes Fechados , Supermercados , China , Poluição do Ar em Ambientes Fechados/prevenção & controle , Poluição do Ar em Ambientes Fechados/análise , Bactérias/isolamento & purificação , Bactérias/classificação , Fungos/isolamento & purificação , Staphylococcus/isolamento & purificação , Aspergillus/isolamento & purificação , Humanos , Bacillus/isolamento & purificação , Monitoramento Ambiental/métodosRESUMO
The beneficial effects of feeding probiotic Bacillus subtilis DSM 32315 (BS) and Bacillus velezensis CECT 5940 (BV) to chickens in vivo are well-documented, with potential immune modulation as a key mechanism. In this study, we investigated the direct interactions of chicken peripheral blood mononuclear cells (PBMCs) with BS or BV in vitro through whole transcriptome profiling and cytokine array analysis. Transcriptome profiling revealed 20 significantly differentially expressed genes (DEGs) in response to both Bacillus treatments, with twelve DEGs identified in BS-treated PBMCs and eight in BV-treated PBMCs. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated significant regulation of immune-related pathways by both BS and BV. Notably, BS treatment upregulated genes associated with immune cell surface markers (CD4, CD25, CD28), anti-inflammatory cytokine interleukin-10 (IL-10), and C-C motif chemokine ligand 5 (CCL5), while downregulating the gene encoding pro-inflammatory IL-16. BV treatment similarly affected genes associated with immune cell surface markers, IL-16, and CCL5, with no impact on the gene encoding IL-10. Both treatments induced higher expression of the gene encoding the avian ß-defensin 1 (AvBD1). The results of this in vitro study indicate an immunomodulatory effect of BS and BV in chicken PBMCs by regulating genes involved in anti-inflammatory, bacteriostatic, protective, and pro-inflammatory responses. Consequently, BS and BV may serve to augment the immune system's capacity to defend against infection by modulating immune responses and cytokine expression. Thus, the administration of these probiotics holds promise for reducing reliance on antimicrobials in farming practices.
Assuntos
Bacillus , Galinhas , Citocinas , Leucócitos Mononucleares , Probióticos , Animais , Galinhas/imunologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Citocinas/metabolismo , Perfilação da Expressão Gênica , Imunomodulação , Bacillus subtilis/imunologia , Células Cultivadas , TranscriptomaRESUMO
Thin layer chromatography-direct bioautography (TLC-DB) is a well-established bioassay used to separate and identify natural products (NPs) that are antagonistic against a target pathogen. It is a rapid, inexpensive, and simple option for the bioassay-guided isolation and identification of NPs that hinges on separation by TLC coupled with the direct application of a target pathogen to examine bioactivity. It is typically used for the analysis of bioactive plant extracts, detecting inhibitory activity against bacteria, fungi, and enzymes. That being said, it has great potential in bacterial NP discovery, particularly for evaluating bacterial NPs against pertinent agricultural pathogens, which is valuable for discovering and developing novel biopesticides for the agriculture industry. Furthermore, it is a tunable protocol that could be applied to other target pathogens or sources of NPs in research programs concerning the discovery and identification of bioactive compounds. Herein, we describe a model system for discovering and identifying biopesticide NPs using TLC-DB with Bacillus spp. and the agricultural pathogen Sclerotinia sclerotiorum.
Assuntos
Ascomicetos , Bioensaio , Produtos Biológicos , Cromatografia em Camada Fina/métodos , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Ascomicetos/química , Bioensaio/métodos , Bacillus/química , Agentes de Controle Biológico/farmacologia , Agentes de Controle Biológico/químicaRESUMO
Probiotics are live microorganisms that, when administered in adequate quantities, provide health benefits to the host. In this study, phenotypic and genotypic methods were used to evaluate the probiotic properties of Bacillus altitudinis 1.4. The isolate was sensitive to all antimicrobials tested and presented a positive result in the hemolysis test. B. altitudinis 1.4 spores were more resistant than vegetative cells, when evaluated in simulation of cell viability in the gastrointestinal tract, as well as adhesion to the intestinal mucosa. The isolate was capable of self-aggregation and coaggregation with pathogens such as Escherichia coli ATCC 25922 and Salmonella Enteritidis ATCC 13076. Genomic analysis revealed the presence of genes with probiotic characteristics. From this study it was possible to evaluate the gene expression of pro-inflammatory and anti-inflammatory cytokines for different treatments. Viable vegetative cells of B. altitudinis 1.4 increased the transcription of pro-inflammatory factors, in addition to also increasing the transcription of IL-10, indicating a tendency to stimulate a pro-inflammatory profile. Given the results presented, B. altitudinis 1.4 showed potential to be applied in the incorporation of this microorganism into animal feed, since the spores could tolerate the feed handling and pelletization processes.
Assuntos
Bacillus , Genoma Bacteriano , Probióticos , Probióticos/farmacologia , Bacillus/genética , Fatores Imunológicos/farmacologia , Citocinas/metabolismo , Citocinas/genética , Escherichia coli/genética , Esporos Bacterianos/genética , Aderência Bacteriana , Salmonella enteritidis/genética , Ração Animal/microbiologia , Antibacterianos/farmacologia , AnimaisRESUMO
In order to investigate the mechanism of plant growth promoting (PGP) effects of strain Bacillus velezensis WSW007, its PGP traits and production of volatile organic compounds (VOCs) were tested. The effects of VOCs produced by strain WSW007 on plant growth were observed by co-culturing this strain with tobacco seedlings in I-plates. Meanwhile, the effects of VOCs on tobacco gene expression were analysed by a transcriptome analysis and VOCs were identified by solid phase micro extraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) analysis. As results, strains WSW007 produced acetic acid and siderophore, and could solubilize phosphate; while it also significantly increased the fresh weight of tobacco seedlings via production of VOCs. In transcriptome analysis, plants co-cultured with strain WSW007 presented the highest up-regulated expression for the genes involved in plant growth and development processes, implying that the bacterial VOCs played a role as regulator of plant gene expression. Conclusively, the up-regulation in expression of growth- and development-related genes via VOCs production is an important PGP mechanism in strain B. velezensis WSW007.
Assuntos
Bacillus , Regulação da Expressão Gênica de Plantas , Nicotiana , Regulação para Cima , Compostos Orgânicos Voláteis , Bacillus/metabolismo , Bacillus/genética , Compostos Orgânicos Voláteis/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Nicotiana/crescimento & desenvolvimento , Nicotiana/microbiologia , Perfilação da Expressão Gênica , Cromatografia Gasosa-Espectrometria de Massas , Plântula/crescimento & desenvolvimento , Plântula/metabolismoRESUMO
Abiotic stresses significantly impact agricultural productivity and food security. Innovative strategies, including the use of plant-derived compounds and plant growth-promoting rhizobacteria (PGPR), are necessary to enhance plant resilience. This study delved into how Bacillus zanthoxyli HS1 (BzaHS1) and BzaHS1-derived volatile organic compounds (VOC) conferred systemic tolerance against salt and heat stresses in cabbage and cucumber plants. Direct application of a BzaHS1 strain or exposure of BzaHS1-derived VOC to cabbage and cucumber plants promoted seedling growth under stressed conditions. This induced systemic tolerance was associated with increased mRNA expression and enzymatic activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), or ascorbate peroxidase (EC 1.11.1.1), leading to a reduction in oxidative stress in cabbage and cucumber plants. Plants co-cultured with BzaHS1 and exposed to BzaHS1-derived VOC triggered the accumulation of callose and minimized stomatal opening in response to high salt and temperature stresses, respectively. In contrast, exogenous treatment of azelaic acid, a well-characterized plant defense primer, had no significant impact on the seedling growth of cabbage and cucumber plants grown under abiotic stress conditions. Taken together, BzaHS1 and its VOC show potential for enhancing plant tolerance responses to salt and heat stresses through modulation of osmotic stress-regulatory networks.
Assuntos
Bacillus , Cucumis sativus , Estresse Fisiológico , Cucumis sativus/fisiologia , Cucumis sativus/microbiologia , Cucumis sativus/genética , Bacillus/fisiologia , Brassica/fisiologia , Brassica/genética , Brassica/microbiologia , Plântula/fisiologia , Plântula/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/metabolismo , Superóxido Dismutase/metabolismo , Catalase/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Estresse OxidativoRESUMO
BACKGROUND: Natural products are important sources for the discovery of new biopesticides to control the worldwide destructive pests Acyrthosiphon pisum Harris. Here, insecticidal substances were discovered and characterized from the secondary metabolites of the bio-control microorganism Bacillus velezensis strain ZLP-101, as informed by whole-genome sequencing and analysis. RESULTS: The genome was annotated, revealing the presence of four potentially novel gene clusters and eight known secondary metabolite synthetic gene clusters. Crude extracts, prepared through ammonium sulfate precipitation, were used to evaluate the effects of strain ZLP-101 on Acyrthosiphon pisum Harris aphid pests via exposure experiments. The half lethal concentration (LC50) of the crude extract from strain ZLP-101 against aphids was 411.535 mg/L. Preliminary exploration of the insecticidal mechanism revealed that the crude extract affected aphids to a greater extent through gastric poisoning than through contact. Further, the extracts affected enzymatic activities, causing holes to form in internal organs along with deformation, such that normal physiological activities could not be maintained, eventually leading to death. Isolation and purification of extracellular secondary metabolites were conducted in combination with mass spectrometry analysis to further identify the insecticidal components of the crude extracts. A total of 15 insecticidal active compounds were identified including iturins, fengycins, surfactins, and spergualins. Further insecticidal experimentation revealed that surfactin, iturin, and fengycin all exhibited certain aphidicidal activities, and the three exerted synergistic lethal effects. CONCLUSIONS: This study improved the available genomic resources for B. velezensis and serves as a foundation for comprehensive studies of the insecticidal mechanism by Bacillus velezensis ZLP-101 in addition to the active components within biological control strains.
Assuntos
Afídeos , Bacillus , Inseticidas , Lipopeptídeos , Animais , Afídeos/efeitos dos fármacos , Bacillus/genética , Bacillus/metabolismo , Lipopeptídeos/farmacologia , Lipopeptídeos/química , Lipopeptídeos/metabolismo , Lipopeptídeos/isolamento & purificação , Inseticidas/farmacologia , Inseticidas/metabolismo , Inseticidas/química , Família Multigênica , Metabolismo Secundário , Controle Biológico de Vetores , Sequenciamento Completo do Genoma , Genoma Bacteriano/genéticaRESUMO
Viral diseases are a serious threat to humans while the most antiviral drugs have low efficiency and side effects on human health. Therefore, using microbial biopolymers as the drugs alternate to treat viral infections seems cost-effective and human friendly option. In the present study, thirty-four exopolysaccharides (EPSs) producing bacteria were isolated, and EPSs production capacity of five salt-tolerant isolates was determined under 0, 100 and 150 mM NaCl. Among these, two isolates exhibiting high anti-coliphage activity were identified through 16S rRNA gene analysis. Moreover, the EPSs were characterized by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis, and their composition was determined. Five salt-tolerant bacteria (MK1, MK2, MK10, MK22 and MK29) exhibited higher production of EPSs at 100 mM NaCl compared to that under non-saline control. At 100 mM NaCl, the yield of EPSs ranged between 105 and 330 mg 100 mL-1 broth. The EPSs produced by the isolates MK1 and MK2 exhibited higher anti-coliphage activity (plaque forming unit decreased from 43 × 106 mL-1 to 3 × 106 and 4 × 106 mL-1, respectively), and were comprised of glucose, fructose, galactose, sucrose, lactose and xylose sugars. FTIR spectroscopy depicted that EPSs are mainly composed of hydroxyl, aliphatic, carboxyl, sulfate and phosphate functional groups, which could have bound coliphage and thus conferred higher anti-coliphage activities to the EPSs. Phylogenetic analysis revealed that MK1 and MK2 isolates formed clades within genus Priestia and Bacillus sequences, respectively. High EPSs production capacity of bacterial isolates under saline condition and high anti-coliphage activity of the EPSs implies that bacterial biopolymers could be useful in antiviral drugs therapy.
Assuntos
Antivirais , Bacillus , Polissacarídeos Bacterianos , RNA Ribossômico 16S , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Antivirais/farmacologia , Antivirais/química , RNA Ribossômico 16S/genética , Bacillus/genética , Bacillus/metabolismo , Bacillus/química , Bacillus/classificação , Filogenia , Espectroscopia de Infravermelho com Transformada de Fourier , Cloreto de Sódio/farmacologia , Cloreto de Sódio/metabolismoRESUMO
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.
Assuntos
Bacillus , Capsicum , Secas , Plântula , Capsicum/crescimento & desenvolvimento , Capsicum/microbiologia , Capsicum/fisiologia , Bacillus/fisiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Estresse Fisiológico , Germinação , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Microbiologia do Solo , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , MéxicoRESUMO
Due to the low permeability characteristics of the deep gas-containing coal seam, the conventional prevention and control measures that cannot solve the problems of gas outbursts are unsatisfactory for the prevention and control of the coal and gas outbursts disaster. Therefore, in this study, a strain of methane-oxidizing bacteria M07 with high-pressure resistance, strong resistance, and high methane degradation rate was selected from coal mines. The growth and degradation abilities of M07 in chelating wetting agent solutions to assess its adaptability and find the optimal agent-to-M07 ratio. It provides a new method for integrating the reduction of impact tendency and gas pressure in deep coal mines. The experimental results show that M07 is a Gram-positive bacterium of the genus Bacillus, which has strong resistance and adaptability to high-pressure water injection. By degrading 70 mol of methane, M07 produces 1 mol of carbon dioxide, which can reduce gas pressure and reduce the risk of gas outbursts in coal mines. As the experiment proves, the best effect was achieved when the M07 concentration of the chelating wetting agent was 0.05%. The methane-oxidizing bacteria based on the chelating wetting agent as carriers prove a new prevention and control method for the integrated prevention and control of coal and gas outbursts in coal mines and also provide a new idea for microbial application in coal mine disaster control.
Assuntos
Biodegradação Ambiental , Quelantes , Metano , Metano/metabolismo , Metano/química , Quelantes/química , Quelantes/farmacologia , Quelantes/metabolismo , Bacillus/metabolismo , Carvão Mineral , Minas de CarvãoRESUMO
The efficiency of aerobic biodegradation of distillery wastewater using various microbial cultures is intricately linked to process conditions. The study aimed to examine the aerobic biodegradation by a Bacillus bacteria under controlled dissolved oxygen tension (DOT) conditions as a novel approach in the treatment of sugar beet distillery stillage. The processes were conducted in a 2-L Biostat®B stirred-tank reactor (STR), at a temperature of 36°C, with aeration of 1.0 L/(L·min), and uncontrolled pH of the medium (an initial pH of 8.0). Each experiment was performed at a different DOT setpoint: 75%, 65% and 55% saturation, controlled through stirrer rotational speed adjustments. The study showed that the DOT setpoint did not influence the process efficiency, determined by the pollutant load removal expressed as COD, BOD5 and TOC. In all three experiments, the obtained reduction values of these parameters were comparable, falling within the narrow ranges of 78.6-78.7%, 97.3-98.0% and 75.0-76.4%, respectively. However, the DOT setpoint did influence the rate of process biodegradation. The removal rate of the pollutant load expressed as COD, was the lowest when DOT was set at 55% (0.48 g O2/(Lâ¢h)), and the highest when DOT was set at 65% (0.55 g O2/(Lâ¢h)). For biogenic elements (nitrogen and phosphorus), a beneficial effect was observed at a low setpoint of controlled DOT during biodegradation. The maximum extent of removal of both total nitrogen (54%) and total phosphorus (67.8%) was achieved at the lowest DOT setpoint (55%). The findings suggest that conducting the batch aerobic process biodegradation of sugar beet stillage at a relatively low DOT setpoint in the medium might achieve high efficiency pollutant load removal and potentially lead to a reduction in the process cost.