Phylogenetic characterization and biodiversity of spore-forming bacteria isolated from Brazilian UHT milk.

Among the milk contaminating microorganisms, those which are able to form heat-resistant spores are concerning, especially for dairy companies that use ultra-high temperature (UHT) technology. These spores, throughout storage, can germinate and produce hydrolytic enzymes that compromise the quality of the final product. This study evaluated 184 UHT milk samples from different batches collected from seven Brazilian dairy companies with a possible microbial contamination problem. The bacteria were isolated, phenotypically characterized, clustered by REP-PCR, and identified through 16S rDNA sequencing. The presence of Bacillus sporothermodurans was verified using biochemical tests (Gram staining, catalase and oxidase test, glucose fermentation, esculin hydrolysis, nitrate reduction, and urease test). According to these tests, none of the isolates presented typical characteristics of B. sporothermodurans. In sequence, the isolates, that presented rod-shapes, were submitted to molecular analyses in order to determine the microbial biodiversity existing among them. The isolates obtained were grouped into 16 clusters, four of which were composed of only one individual. A phylogenetic tree was constructed using the sequences obtained from the 16S rDNA sequencing and some reference strains of species close to those found using BLAST search in the NCBI nucleotide database. Through this tree, it was possible to verify the division of the isolates into two large groups, the Bacillus subtilis and the Bacillus cereus groups. Furthermore, most isolates are phylogenetically closely related, which makes it even more difficult to identify them at the species level. In conclusion, it was possible to assess, in general, the groups of sporulated contaminants in Brazilian UHT milk produced in the regions evaluated. In addition, it was also possible to determine the biodiversity of spore-forming bacteria found in UHT milk samples, thus opening up a range of possible research topics regarding the effects of the presence of these microorganisms on milk quality.

Initial development of upland rice inoculated and co-inoculated with multifunctional rhizobacteria / Desenvolvimento inicial de arroz de terras altas inoculado e coinoculado com rizobactérias multifuncionais

Inoculation and co-inoculation of upland rice with multifunctional rhizobacteria can promote plant growth, especially the root system. Thus, this study aimed to evaluate the effect of inoculation and co-inoculation with Azospirillum sp. and Bacillus sp. in the early development of upland rice. The experiment was conducted using a completely randomized design with 4 treatments and 10 replications, totaling 40 plots. The treatments were: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) co-inoculation of Ab-V5 + BRM 63573, and 4) control (without rhizobacteria). Inoculation and co-inoculation with the multifunctional rhizobacteria Ab-V5 and BRM 63573 provided positive effects on the initial development of upland rice. Inoculation with isolate BRM 63573 had significant effects on root length, shoot, and total biomass, while inoculation with isolate Ab-V5 had significant effects on root length and production of root and total biomass. Co-inoculation treatment had significant effects on variables such as diameter, volume, total surface, root biomass, and total biomass. The control treatment (without multifunctional rhizobacteria) had the worst results for most of the analyzed variables.

A inoculação e coinoculação do arroz de terras altas com rizobactérias multifuncionais pode promover o crescimento das plantas, especialmente do sistema radicular. Assim, este estudo teve como objetivo avaliar o efeito da inoculação e coinoculação com Azospirillum sp. e Bacillus sp. no desenvolvimento inicial do arroz de terras altas. O experimento foi conduzido em delineamento inteiramente casualizado com 4 tratamentos e 10 repetições, totalizando 40 parcelas. Os tratamentos foram: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) coinoculação de Ab-V5 + BRM 63573 e 4) controle (sem rizobactérias). A inoculação e coinoculação com as rizobactérias multifuncionais Ab-V5 e BRM 63573 proporcionaram efeitos positivos no desenvolvimento inicial do arroz de terras altas. A inoculação com o isolado BRM 63573 teve efeitos significativos no comprimento da raiz, parte aérea e biomassa total, enquanto a inoculação com o isolado Ab-V5 teve efeitos significativos no comprimento da raiz e produção de raiz e biomassa total. O tratamento com coinoculação teve efeitos significativos em variáveis como diâmetro, volume e superfície total de raiz e biomassa de raiz e total. O tratamento controle (sem rizobactérias multifuncionais) apresentou os piores resultados para a maioria das variáveis analisadas.

Caracterización bioinformática y producción de L-asparaginasa de Bacillus sp. M62 aislado de las salinas de Maras, Cusco, Perú

El objetivo del estudio fue realizar la caracterización bioinformática, así como optimizar la producción de L-asparaginasa extracelular de Bacillus sp. M62 aislada de las salinas de Maras (Cusco). Para ello, se verificó la producción de L-asparaginasa mediante el viraje del medio M9 modificado con azul de bromofenol 0.0075%, pH 7.4 a 37 °C por 72 h. A la vez, se extrajo el ADN genómico para amplificar los genes ribosómicos 16S y el gen ansA3. La secuencia aminoacídica codificada por el gen ansA3 se predijo mediante análisis bioinformático. La producción de L-asparaginasa intracelular y extracelular se evaluó a diferentes niveles de glucosa, L-asparagina, NaCl y pH en el medio M9 modificado. Adicionalmente, las actividades enzimáticas de L-asparaginasa y L-glutaminasa se determinaron mediante cuantificación del amonio liberado por el método de Nessler. Así, Bacillus sp. M62 produjo el viraje del medio M9 modificado, obtuvo alta similitud y cercanía evolutiva con Bacillus licheniformis, se encontró que el gen ansA3 amplificado codificaba para 319 aa, dentro de la cual se predijo una secuencia patrón del sitio activo (GFVITHGTDTM ) y 15 sitios inmunogénicos. La producción de L-asparaginasa extracelular fue superior a la intracelular, la que se optimizó de 0.37 U/mL (0.24 U/mg) a 2.15 ± 0.39 U/mL (0.63 U/mg). Finalmente, se encontró que Bacillus sp. M62 presenta L-asparaginasa extracelular con mínima actividad de L-glutaminasa.

The aim of this study was to perform bioinformatics characterization and optimize the production of extracellular L-asparaginase from Bacillus sp. M62, isolated from the Maras salt ponds (Cusco). To achieve this, the production of L-asparaginase was verified by the change in color of modified M9 medium, containing 0.0075% bromophenol blue, at pH 7.4 and 37°C for 72 hours. Genomic DNA was extracted to amplify the 16S ribosomal genes and the ansA3 gene. The amino acid sequence encoded by the ansA3 gene was predicted using bioinformatic analysis. The production of intracellular and extracellular L-asparaginase was evaluated at different levels of glucose, L-asparagine, NaCl, and pH in modified M9 medium. Additionally, the enzymatic activities of L-asparaginase and L-glutaminase were determined by quantifying the released ammonium using the Nessler method. Bacillus sp. M62 showed the change in color of the modified M9 medium, high similarity, and evolutionary closeness to Bacillus licheniformis. The amplified ansA3 gene was found to encode for 319 amino acids, with a predicted active site pattern (GFVITHGTDTM) and 15 immunogenic sites. The production of extracellular L-asparaginase was found to be higher than intracellular L-asparaginase and was optimized from 0.37 U/mL (0.24 U/mg) to 2.15 ± 0.39 U/mL (0.63 U/mg). Finally, it was found that Bacillus sp. M62 presents extracellular L-asparaginase with minimal L-glutaminase activity.

The antagonistic potential of peanut endophytic bacteria against Sclerotium rolfsii causing stem rot.

Peanut stem rot caused by Sclerotium rolfsii Sacc. is the most common disease of peanut worldwide and has become increasingly serious in recent years. This study is aimed at obtaining peanut endophytic bacteria with high antagonistic/protective effects against peanut stem rot. In total, 45 bacterial strains were isolated from healthy peanut plants from a severely impacted area. Of these, 6 exhibited antagonistic activity against S. rolfsii, including F-1 and R-11 with the most robust activity with an inhibition zone width of 20.25 and 15.49 mm, respectively. These two were identified as Bacillus sp. and Burkholderia sp., respectively, based on morphological, physiological, and biochemical characteristics and 16S rDNA sequencing. To the best of our knowledge, this is the first study to report the Burkholderia sp. antagonistic effect on S. rolfsii as a biological control agent for peanut stem rot. Their culture filtrates potently inhibited the hyphal growth, sclerotial formation, and germination of S. rolfsii. Also, the strain-produced volatile compounds inhibited the fungal growth. Pot experiments showed that F-1 and R-11 significantly reduced the peanut stem rot disease with the efficacy of 77.13 and 64.78%, respectively, which was significantly higher compared with carbendazim medicament (35.22%; P < 0.05). Meanwhile, F-1 and R-11 improved the activity of plant defense enzymes such as phenylalaninase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) enhancing the systemic resistance of the peanut plants. This study demonstrated that Bacillus sp. F-1 and Burkholderia sp. R-11, with a strong antagonistic effect on S. rolfsii, can be potential biocontrol agents for peanut stem rot.

Characterization of biosurfactant produced in response to petroleum crude oil stress by Bacillus sp. WD22 in marine environment.

Bacillus sp. WD22, previously isolated from refinery effluent, degraded 71% of C8 hydrocarbons present in 1.0% v/v PCO in seawater (control medium), which reduced to 16.3%, on addition of yeast extract. The bacteria produced a biosurfactant in both media, whose surface was observed to be amorphous in nature under FESEM-EDAX analysis. The biosurfactant was characterized as a linear surfactin by LCMS and FT-IR analysis. The critical micelle concentration was observed as 50 mg/L and 60 mg/L at which the surface tension of water was reduced to 30 mN/m. Purified biosurfactant could emulsify petroleum-based oils and vegetable oils effectively and was stable at all tested conditions of pH, salinity and temperature up to 80 °C. The biosurfactant production was found to be mixed growth associated in control medium, while it was strictly growth associated in medium with yeast extract as studied by the Leudeking-Piret model.

Effect of Aspergillus and Bacillus Concentration on Cotton Growth Promotion.

There are no studies in literature on the effect of inoculant concentrations on plant growth promotion. Therefore, in the present study, two experiments were carried out, one under pot conditions and the other in the field with cotton crop, in order to verify the effect of Aspergillus and Bacillus concentrations on the biometric and nutritional parameters of plant and soil, in addition to yield. The pot experiment evaluated the effect of different concentrations, ranging from 1 × 104 to 1 × 1010 colony-forming units per milliliter (CFU mL-1) of microorganisms Bacillus velezensis (Bv188), Bacillus subtilis (Bs248), B. subtilis (Bs290), Aspergillus brasiliensis (F111), Aspergillus sydowii (F112), and Aspergillus sp. versicolor section (F113) on parameters plant growth promotion and physicochemical and microbiological of characteristics soil. Results indicated that the different parameters analyzed are influenced by the isolate and microbial concentrations in a different way and allowed the selection of four microorganisms (Bs248, Bv188, F112, and F113) and two concentrations (1 × 104 and 1 × 1010 CFU mL-1), which were evaluated in the field to determine their effect on yield. The results show that, regardless of isolate, inoculant concentrations promoted the same fiber and seed cotton yield. These results suggest that lower inoculant concentrations may be able to increase cotton yield, eliminating the need to use concentrated inoculants with high production cost.

Proteomic analysis of secretomes from Bacillus sp. AR03: characterization of enzymatic cocktails active on complex carbohydrates for xylooligosaccharides production.

Bacillus sp. AR03 have been described as an important producer of carbohydrate-active enzymes (CAZymes) when growing in a peptone-based medium supplemented with simple sugars and/or carboxymethyl cellulose (CMC) as carbon sources. This work aimed to identify the extracellular enzymatic cocktails through shotgun proteomics. The proteomic analysis showed that enzymes involved in cellulose and xylan degradation were among the most abundant proteins. These enzymes included an endo-glucanase GH5_2 and a glucuronoxylanase GH30_8, which were found in all conditions. In addition, several proteins were differentially expressed in the three evaluated culture media, indicating microbial metabolic changes due to the different supplied carbon sources, particularly, in the presence of CMC. Finally, the capability of the crude enzymatic cocktails from culture media to degrade birchwood xylan was assessed, which produced mostly xylooligosaccharides containing among 3-5 xylose units. Consequently, this work shows the potential of the extracellular enzymes from Bacillus sp. AR03 for producing emergent prebiotics.

Necrotizing placentitis in a cow caused by Bacillus cereus / Placentite necrotizante em uma vaca por Bacillus cereus

This report described a case of necrotizing placentitis caused by Bacillus cereus in a cow associated with abortion and maternal lethality. The etiological diagnosis of placentitis by B. cereus was based on histopathology of placenta, cytology and bacterial isolation from intrauterine aminiotic fluid in retained placenta and further characterization of the pathogen by the MALDI-TOF. Although, B. cereus abortions are sporadic, the bacterium has the ability to release necrotizing toxins that can lead to placentitis, fetal death and abortion.(AU)

Este relato descreve a placentite necrotizante causada por Bacillus cereus em uma vaca associada a aborto e mortalidade materna. O diagnóstico etiológico de placentite por B. cereus foi baseado na histopatologia da placenta, citologia e isolamento bacteriano partir do líquido aminiótico em placenta retida e identificação do patógeno pela técnica de MALDI-TOF. Embora abortos por B. cereus sejam esporádicos, a bactéria tem a capacidade de liberar toxinas necrotizantes que podem levar a placentite e aborto.(AU)

Growth and production of 'Prata Anã Gorutuba' banana under different planting densities

Increased planting density, different types of thinning management, and the use of beneficial microorganisms have been adopted as strategic tools in the effort to increase crop yields in a sustainable manner. This investigation evaluated the growth and production of ‘Prata Anã Gorutuba’ banana ( Musa spp., AAB) under different plant densities during two production cycles in the semiarid region of Minas Gerais, Brazil. Micropropagated plantlets were also inoculated with endophytic bacteria and cultivated as part of two mat management strategies. Planting density varied between 1,680 and 3,920 plant ha–1. During the experiment, water was less than optimal because of rationing due to drought in the region. Under field conditions, there was no difference between bacterially inoculated and non-inoculated plants. The dense planting system increased the crop cycle. The highest-density planting treatment (3,920 plant ha–1) resulted in the highest yield in the first cycle, but no net income was observed. However, the high-density planting treatments resulted in the highest yields and gross incomes in the second production cycle. Management with thinning of plants up to 10-months-old and thinning up to harvest associated with high planting density increased the length of the production cycles. Although the water restriction experienced in the first and second crop cycles, the vegetative and productive traits of ‘Prata Anã Gorutuba’ banana did not compromise the objectives of this study.

Necrotizing placentitis in a cow caused by Bacillus cereus / Placentite necrotizante em uma vaca por Bacillus cereus

ABSTRACT: This report described a case of necrotizing placentitis caused by Bacillus cereus in a cow associated with abortion and maternal lethality. The etiological diagnosis of placentitis by B. cereus was based on histopathology of placenta, cytology and bacterial isolation from intrauterine aminiotic fluid in retained placenta and further characterization of the pathogen by the MALDI-TOF. Although, B. cereus abortions are sporadic, the bacterium has the ability to release necrotizing toxins that can lead to placentitis, fetal death and abortion.

RESUMO: Este relato descreve a placentite necrotizante causada por Bacillus cereus em uma vaca associada a aborto e mortalidade materna. O diagnóstico etiológico de placentite por B. cereus foi baseado na histopatologia da placenta, citologia e isolamento bacteriano partir do líquido aminiótico em placenta retida e identificação do patógeno pela técnica de MALDI-TOF. Embora abortos por B. cereus sejam esporádicos, a bactéria tem a capacidade de liberar toxinas necrotizantes que podem levar a placentite e aborto.

Growth and production of 'Prata Anã Gorutuba' banana under different planting densities

Increased planting density, different types of thinning management, and the use of beneficial microorganisms have been adopted as strategic tools in the effort to increase crop yields in a sustainable manner. This investigation evaluated the growth and production of ‘Prata Anã Gorutuba banana ( Musa spp., AAB) under different plant densities during two production cycles in the semiarid region of Minas Gerais, Brazil. Micropropagated plantlets were also inoculated with endophytic bacteria and cultivated as part of two mat management strategies. Planting density varied between 1,680 and 3,920 plant ha–1. During the experiment, water was less than optimal because of rationing due to drought in the region. Under field conditions, there was no difference between bacterially inoculated and non-inoculated plants. The dense planting system increased the crop cycle. The highest-density planting treatment (3,920 plant ha–1) resulted in the highest yield in the first cycle, but no net income was observed. However, the high-density planting treatments resulted in the highest yields and gross incomes in the second production cycle. Management with thinning of plants up to 10-months-old and thinning up to harvest associated with high planting density increased the length of the production cycles. Although the water restriction experienced in the first and second crop cycles, the vegetative and productive traits of ‘Prata Anã Gorutuba banana did not compromise the objectives of this study.(AU)

Production of fructooligosaccharides by Bacillus subtilis natto CCT7712 and their antiproliferative potential.

AIMS: Fructooligosaccharides (FOSs) known for their health properties and ß-(2→6)-levan-type FOSs have shown prebiotic and immunomodulatory activities that overcome those of commercial ß-(2→1)-FOSs, but costs do not favour their use. Moreover, FOSs can reach the bloodstream through the diet, and little is known about their direct effect on cells. The aim of this work was to produce high-content FOSs by Bacillus subtilis natto CCT7712 in a bioreactor using commercial sucrose and to evaluate their antiproliferative effects in OVCAR-3 cells. METHODS AND RESULTS: FOS production reached 173·60 g l-1 , 0·2 vvm aeration and uncontrolled pH. Levan-type FOSs, composed of ß-(2 â†’ 6) links and mainly GF3 (6-nystose), were identified using RMN spectroscopy, FT-IR and ESI-MS. FOSs decreased the viability and proliferation of OVCAR-3 cells, and the effects were associated with an increased pro-inflammatory response by the induction of IL-8 and TNF-α, and the repression of ER-ß genes. The metabolic profiles showed disruption of cellular homeostasis that can be associated with a decrease in proliferation. CONCLUSIONS: The high production of levan-type FOSs from B. subtilis natto CCT7712 in a bioreactor was achieved, and they showed antiproliferative potential in OVCAR-3 cells. SIGNIFICANCE AND IMPACT OF THE STUDY: FOS could be a good target for future therapeutic studies and commercial use.

Inoculation of plant growth-promoting bacteria attenuates the negative effects of drought on sorghum.

Microbial inoculants are suitable cost-effective technology to help plants endure drought. For the development of commercial inoculants, screening of efficient plant growth-promoting bacteria (PGPB) is a crucial step. The aim of this study was to evaluate the performance of PGPB to modulate drought resistance in Sorghum bicolor. A pot experiment with sorghum was conducted to access the role of previously selected PGPB strains. In addition, two non-inoculated control treatments (with and without urea fertilization) were also evaluated. For comparison, a fully irrigated treatment (FIT) was also assessed. All plants were fully irrigated for 47 days when the water supply was completely suspended for the drought-stressed treatments. When the soil moisture was close to zero, the irrigation was resumed. During dehydration and rehydration process, the leaf gas exchange (LGE) was evaluated. The parameters of plant growth and nitrogen nutrition were assessed 8 days after reirrigation. Comparing to the FIT, all treatments reduced the LGE rates, but in the presence of Bacillus sp. ESA 402 photosynthesis rate was less reduced. Some inoculation treatments promoted better recovery of photosynthesis, comparable to the FIT, 6 days after rehydration. The plant growth and nitrogen nutrition were negatively affected by the drought, but the inoculation of different bacteria reduced some negative effects. The nitrogen accumulation in the shoots was increased by all strains, suggesting their diazotrophic ability even under drought. Overall, the inoculation of Bacillus sp. ESA 402 was the best bacterium with potential for future field trials.

Antimicrobial activity of enterocins against Listeria sp. and other food spoilage bacteria.

OBJECTIVE: To determine bacteriocin producers and the prevalence of structural enterocin genes and to detect the spectrum of activity against foodborne pathogens, from isolates of Enterococcus faecium and Enterococcus faecalis that were isolated from food and the environment. RESULTS: The entA, entB, entP, ent1071 and entX genes, which encode enterocins were the most frequently observed. Enterocins were thermostable, proteinaceous, and resistant to catalase. None of the isolates produced hemolysin, and inhibition resulting from bacteriophage lysis was excluded. The bactericidal effect of enterocins against L. innocua 12612 was determined by optical density and colony forming units. For the activity spectrum, elimination of mainly Listeria strains, Bacillus sp. and clinical enterococci, was observed. Imaging with scanning electron microscopy after treatment with enterocin Efm22 showed irregular rod-shaped cells and loss of cellular integrity. CONCLUSIONS: The isolates evaluated in this study are candidates for the production of enterocins that will be used as food biopreservatives, because they have high anti-listerial activity even after 24 h of experimentation, and used in the pharmaceutical area because they inhibit clinical microorganisms.

Isolated Phosphate-Solubilizing Soil Bacteria Promotes In vitro Growth of Solanum tuberosum L.

The capacity of four bacterial strains isolated from productive soil potato fields to solubilize tricalcium phosphate on Pikovskaya agar or in a liquid medium was evaluated. A bacterial strain was selected to evaluate in vitro capacity of plant-growth promotion on Solanum tuberosum L. culture. Bacterial strain A3 showed the highest value of phosphate solubilization, reaching a 20 mm-diameter halo and a concentration of 350 mg/l on agar and in a liquid medium, respectively. Bacterial strain A3 was identified by 16S rDNA analysis as Bacillus pumilus with 98% identity; therefore, it is the first report for Bacillus pumilus as phosphate solubilizer. Plant-growth promotion assayed by in vitro culture of potato microplants showed that the addition of bacterial strain A3 increased root and stems length after 28 days. It significantly increased stem length by 79.3%, and duplicated the fresh weight of control microplants. In this paper, results reported regarding phosphorus solubilization and growth promotion under in vitro conditions represent a step forward in the use of innocuous bacterial strain biofertilizer on potato field cultures.

Bacillus natronophilus sp. nov., an alkaliphilic bacterium isolated from a soda lake.

An alkaliphilic, moderately halophilic, heterotrophic, rod-shaped, spore-forming bacterium (M30T) was isolated from a sediment sample collected from a soda lake (Lake Magadi, Tanzania). Strain M30T was strictly aerobic, catalase-positive, oxidase-negative and non-motile. Growth occurred at 12-43 °C (optimum, 25-30 °C), at pH 8.0-12 (optimum, pH 9.5-10) and at salinities of 0.5-15 % (w/v) NaCl (optimum 5 %). It utilized various sugars and organic acids as sole carbon sources and was positive for amylase, cellulase, gelatinase, protease and xylanase activities. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified lipid and one unidentified phospholipid. The DNA G+C content was 48.9 mol%. The predominant menaquinone was MK-7 and the major fatty acids (>10 %) comprised anteiso-C15 : 0, iso-C15 : 0, and anteiso-C17 : 0. Phylogenetic analysis based on 16S rRNA gene sequence affiliated M30T to the genus Bacillus and showed the highest similarities to Bacillus populi FJAT-45347T (96.4 %) and Bacillus aurantiacus K1-5T (96.2 %). Based on the data from the current polyphasic study, M30T represents a novel species of the genus Bacillus, for which the name Bacillus natronophilus sp. nov. is proposed. The type strain is M30T (=JCM 32118T=CGMCC 1.16739T=MCC 3010T).

Physiological response of Lactuca sativa exposed to 2-nonanone emitted by Bacillus sp. BCT9.

Volatile organic compounds (VOCs) released from bacterial species have been reported as plant growth inducers. In this sense, Lactuca sativa was used as model vegetable to prospect the effects of 2-nonanone released by Bacillus sp. BCT9 at cellular and organ structure level, so we present preliminary results about the physiological effects. In this study, 2-day-old L. sativa were exposed to 2-nonanone for 10 days under two delivery systems: 1) 2-nonanone (abrupt delivery) and 2) 2-nonanone + lanolin (controlled delivery). The X-ray elemental microanalysis, scanning electron and confocal laser microscopies techniques were used to evaluate physiological changes "in vivo" conditions. The results indicated that 2-nonanone increased root and shoot length independently of 2-nonanone delivery system after 7 days of exposition. Additionally, 2-nonanone elicited the increase of anthocyanin and not affects chlorophyll content and electrolyte leakage percentage. The abrupt delivery elicited the increase of both length and density of root hair without causing changes in size of cell epidermis, while controlled delivery induced stomatal opening. Besides, 2-nonanone exposition did not modify the composition and distribution of carbon, nitrogen, phosphorus, potassium, and chlorine in the surface of plant tissue. The results suggested that 2-nonanone acts as a bacterial signal molecule to elicit changes related to root development without damaging the external morphology while epidermal cells at leaf level are not affected, suggesting that 2-nonanone can be an important tool to apply to vegetables.

Chemical Compounds Produced by Bacillus sp. Factories and Their Role in Nature.

Microorganisms are able to produce hundreds of unique chemical structures that can be effectively used by the human beings on their own benefit using the products in the chemical industry. Bacteria belonging to Bacillus genera are very good chemical factories capable to synthesize different compounds with a wide variety of activities. In this review, we try to review the compounds with their respective biological activities produced by different species of Bacillus.

Production of a microbial emulsifier with biotechnological potential for environmental applications.

The present work reports the production of bioemulsifiers (BEs) by an environmental bacterium closely related to Bacillus spp., using agro-industrial wastes and by-products as low-cost carbon sources. Maximum emulsifying activity was detected using crude glycerol (CG) (E24 = 59%), producing 2.8 g/L of BE at 24 h of incubation. The microbial product presented significantly higher biodegradability in comparison to three commercial emulsifying agents (sodium dodecyl sulfate, SDS; Tween 80; and Arabic gum, AG). Interestingly, BE proved to be innocuous for Caco-2 cells and wheat seedlings, used as toxicological indicators. The BE and AG showed (in most of the cases) higher stability to changes in temperature (37 °C-100 °C), pH (3-10), and salt concentration (5% and 10%, w/v) in comparison to the SDS and Tween 80. Finally, the microbial product displayed a large affinity to a wide range of hydrophobic substrates showing emulsifying activities similar to or even better than SDS, Tween 80 and AG. The results presented in this study demonstrate the potential of a bioproduct obtained from CG to be used for environmental purposes.

Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems.

Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant-microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition-FISH (CARD-FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0-30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD-FISH methodologies were both successful in detecting B. subtilis colonies, but CARD-FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD-FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants.