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1.
Nat Commun ; 11(1): 950, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32075967

RESUMO

Stochastic pulsing of gene expression can generate phenotypic diversity in a genetically identical population of cells, but it is unclear whether it has a role in the development of multicellular systems. Here, we show how stochastic pulsing of gene expression enables spatial patterns to form in a model multicellular system, Bacillus subtilis bacterial biofilms. We use quantitative microscopy and time-lapse imaging to observe pulses in the activity of the general stress response sigma factor σB in individual cells during biofilm development. Both σB and sporulation activity increase in a gradient, peaking at the top of the biofilm, even though σB represses sporulation. As predicted by a simple mathematical model, increasing σB expression shifts the peak of sporulation to the middle of the biofilm. Our results demonstrate how stochastic pulsing of gene expression can play a key role in pattern formation during biofilm development.


Assuntos
Bacillus subtilis/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Bacillus subtilis/metabolismo , Bacillus subtilis/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Heterogeneidade Genética , Microscopia de Fluorescência , Modelos Biológicos , Fator sigma/genética , Fator sigma/metabolismo , Esporos Bacterianos/genética , Esporos Bacterianos/metabolismo , Esporos Bacterianos/fisiologia , Processos Estocásticos , Estresse Fisiológico , Imagem com Lapso de Tempo
2.
Syst Appl Microbiol ; 43(2): 126055, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31992497

RESUMO

Fifteen enterobacterial strains were isolated from fresh produce. The 16S rRNA gene sequences indicated that these belong to Serratia, with twelve strains showing 99.57%-99.93% and three strains showing 99.86-100% 16S rRNA gene sequence similarity with Serratia marcescens and Serratia nematodiphila as nearest neighbors, respectively. Further comparative multi locus sequence analyses, as well as phylogenomic comparisons, revealed that 6 of the 15 strains were well-separated from their nearest neighbors and formed two clearly distinct taxa. Strains S2, S9, S10 and S15T were urease-positive, while strains S3T and S13 were urease-negative. Average nucleotide identity and digital DNA-DNA hybridization comparisons of representative strains S3T and S15T with type strains of S. marcescens, S. nematodiphila and S. ureilytica indicated that these shared less than 96% and 70% homology, respectively. Major fatty acids of strains S3T and S15T included C16:0, C16:1 ω7c/C16:1 ω6c, C17:0 Cyclo and C18:1 ω6c /C18:1 ω7c. The mol% G+C of genomic DNA of strain S15T was 59.49% and of strain S3T was 59.04. These results support the description of two novel species, Serratia nevei and Serratia bockelmannii, with strains S15T (=LMG 31536T =DSM 110085T) and S3T (=LMG 31535T =DSM 110152T) as type strains, respectively. Although Serratia marcescens subsp. sakuensis was previously described to form spores, spores could not be determined in this study. As spore formation was the only differential characteristic of this subspecies, S. marcescens subsp. sakuensis is a later heterotypic synonym of Serratia marcescens.


Assuntos
Microbiologia de Alimentos , Filogenia , Serratia/classificação , Proteínas de Bactérias/genética , DNA Bacteriano/genética , Ácidos Graxos/análise , Genoma Bacteriano/genética , Genótipo , Alemanha , Hibridização de Ácido Nucleico , Fenótipo , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Serratia/química , Serratia/genética , Serratia/isolamento & purificação , Esporos Bacterianos/citologia , Esporos Bacterianos/crescimento & desenvolvimento
3.
World J Microbiol Biotechnol ; 36(1): 18, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31912374

RESUMO

In this paper, we report the antimicrobial activity of AMEP412 (a protein elicitor from Bacillus subtilis) against Streptomyces scabiei, which is the potato common scab pathogen. The purified protein samples showed an obvious inhibition zone on an S. scabiei agar plate, and the minimum inhibition concentration detected was 50 µg mL-1. The fluorescence localization assay revealed that AMEP412 could bind to aerial mycelia and spores. The stability test showed that AMEP412 was stable at 60 °C for 30 min and in pH values from 5.0 to 10.0. Its antimicrobial activity was not sensitive to metal cations. However, its activity declined by 23% when treated with Proteinase K, and was completely abrogated with Tween 80 treatment. Three antimicrobial peptides (GS21, GY20 and GY23) were identified from AMEP412, which further verified its antimicrobial activity. This research reveals the antimicrobial function of AMEP412, which not only enriches the function of the protein elicitor, but also provides a candidate for the biocontrol of potato common scab.


Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/metabolismo , Proteínas de Bactérias/farmacologia , Streptomyces/efeitos dos fármacos , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Bactérias/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Solanum tuberosum/microbiologia , Esporos Bacterianos/efeitos dos fármacos , Streptomyces/crescimento & desenvolvimento
4.
Ecotoxicol Environ Saf ; 191: 110184, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31935556

RESUMO

Laccases play a significant role in remedying dye pollutants. Most of these enzymes are originated from terrestrial fungi and bacteria, thus they are not proper to be used in the environments with neutral/alkaline pH, or they may require laborious extraction/purification steps. These limitations can be solved using marine spore laccases through high stability and easy to use application. In the current study, laccase activity of the marine spore -forming Bacillus sp. KC2 was measured according to the guaiacol and syringaldazine oxidation. Abiotic stresses like pH of 6, temperature of 37 °C and 0.3 mM CuSO4 (in comparison with optimal sporulation conditions: pH of 8, temperature of 20 °C and 0.0 mM CuSO4) enhanced laccase formation in sporal coat. Maximum activity of enzyme was observed at 50 °C and pH 7, which did not change in the alkaline pH and temperature range of 20-70 °C. Results indicated ions, inhibitors and solvent stability of the enzyme and its activity were stimulated by Co2+, Mn2+, PMSF, acetone, acetonitrile, ethanol, and methanol. The spore laccase could decolorize synthetic dyes from various chemical groups including azo (acid orange, amaranth, trypan blue, congo red, and amido black), indigo (indigo carmine), thiazine (methylene blue, and toluidine blue), and triarylmethane (malachite green) with ABTS/syringaldazine mediators after 5 h. Degradation products were not toxic against Sorghum vulgare and Artemia salina model organisms. The enzyme mediator system showed high potentials for dye bioremediation over a wide range of harsh conditions.


Assuntos
Corantes/metabolismo , Lacase/metabolismo , Água do Mar/microbiologia , Esporos Bacterianos/enzimologia , Poluentes Químicos da Água/metabolismo , Bacillus/enzimologia , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Oxirredução , Temperatura
5.
Food Microbiol ; 87: 103353, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948638

RESUMO

Bacillus subtilis spore inactivation mechanisms under low energy electron beam (LEEB) and high energy electron beam (HEEB) treatment were investigated using seven mutants lacking specific DNA repair mechanisms. The results showed that most of the DNA repair-deficient mutants, including ΔrecA, ΔKu ΔligD, Δexo Δnfo, ΔuvrAB and ΔsbcDC, had reduced resistances towards electron beam (EB) treatments at all investigated energy levels (80 keV, 200 keV and 10 MeV) compared to their wild type. This result suggested DNA damage was induced during EB treatments. The mutant lacking recA showed the lowest resistance, followed by the mutant lacking Ku and ligD. These findings indicated that recA, Ku and ligD and their associated DNA repair mechanisms, namely, homologous recombination and non-homologous end joining, play important roles in spore survival under EB treatment. Furthermore, exoA, nfo, uvrAB, splB, polY1 and polY2, which are involved in nucleotide damage repair/removal, showed different levels of effects on spore resistance under EB treatment. Finally, the results suggested that HEEB and LEEB inactivate B. subtilis spores through similar mechanisms. This research will provide a better understanding of how EB technologies inactivate B. subtilis spores and will contribute to the application of these technologies as a non-thermal, gentle spore control approach.


Assuntos
Bacillus subtilis/genética , Reparo do DNA , Esporos Bacterianos/efeitos da radiação , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/efeitos da radiação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Dano ao DNA/efeitos da radiação , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Elétrons , Viabilidade Microbiana/efeitos da radiação , Mutação , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento
6.
Nat Chem Biol ; 16(2): 108-109, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31974525
7.
PLoS One ; 15(1): e0228270, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978128

RESUMO

Bacillus anthracis is the causative agent of anthrax in animals and humans. The organism lies in a dormant state in the soil until introduced into an animal via, ingestion, cutaneous inoculation or inhalation. Once in the host, spores germinate into rapidly growing vegetative cells elaborating toxins. When animals die of anthrax, vegetative bacteria sporulate upon nutrient limitation in the carcass or soil while in the presence of air. After release into the soil environment, spores form a localized infectious zone (LIZ) at and around the carcass. Laboratory strains of B. anthracis produce fewer proteins associated with growth and sporulation compared to wild strains isolated from recent zoonotic disease events. We verified wild strains grow more rapidly than lab strains demonstrating a greater responsiveness to nutrient availability. Sporulation was significantly more rapid in these wild strains compared to lab strains, indicating wild strains are able to sporulate faster due to nutrient limitation while laboratory strains have a decrease in the speed at which they utilize nutrients and an increase in time to sporulation. These findings have implications for disease control at the LIZ as well as on the infectious cycle of this dangerous zoonotic pathogen.


Assuntos
Bacillus anthracis/fisiologia , Esporos Bacterianos/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Laboratórios , Microbiologia do Solo , Especificidade da Espécie
8.
Crit Rev Food Sci Nutr ; 60(1): 108-122, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30729793

RESUMO

In the last few decades Gram positive non pathogenic, rod shaped, thermo-acidophilic and acid-tolerant spore-forming bacteria such as Alicyclobacillus spp. have been identified as the causative agent in spoilage of commercially pasteurized fruit juice. In particular, A. acidoterrestris is considered a major producer of off-flavors. The spores of A. acidoterrestris possess the ability to survive commercial pasteurization processes, to germinate and grow in low pH environments and to produce volatile, unpleasant odorous compound (guaiacol) in fruit juices. The flat sour type of spoilage (without gas production or package swelling) is characterized as having a "medicinal," "smoky," and "antiseptic" off-flavor and makes the final juice product unacceptable. Spoilage by Alicyclobacillus is a major concern for producers since many of the new methods, which can destroy spores in the absence of chemical additives, may not destroy Alicyclobacillus. Although A. acidoterrestris is not pathogenic to humans, it can result in significant economic losses to juice processors because of its odor. The present review includes the taxonomy of Alicyclobacillus spp., their general characteristics, their resistance to heat and possible off-flavor production pathways. Particular emphasis is given to commonly used control measures, including physical, chemical and biological treatments currently available for removal of Alicyclobacillus spp.


Assuntos
Alicyclobacillus , Contaminação de Alimentos , Microbiologia de Alimentos , Sucos de Frutas e Vegetais/microbiologia , Guaiacol , Temperatura Alta , Esporos Bacterianos , Paladar
9.
Food Microbiol ; 86: 103325, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703860

RESUMO

Clostridium perfringens SM101 genome encodes three serine proteases (CspA, CspB, and CspC), and genetic evidence indicates that CspB is required for processing of pro-SleC into active SleC, an enzyme essential for degradation of the peptidoglycan cortex during spore germination. In this study, the expression of cspA and cspC, as well as the germination and colony formation by spores of cspAC and cspC mutants of strain SM101, were assessed. We demonstrated that 1) the cspA and cspC genes were expressed as a bicistronic operon only during sporulation in the mother cell compartment of SM101; 2) both cspAC and cspC mutant spores were unable to germinate significantly with either KCl, l-glutamine, brain heart infusion (BHI) broth, or a 1:1 chelate of Ca2+ and dipicolinic acid (DPA); 3) consistent with germination results, both cspAC and cspC mutant spores were defective in normal DPA release; 4) the colony formation by cspAC and cspC mutant spores was ~106-fold lower than that of wild-type spores, although decoated mutant spores yielded wild-type level colony formation on plates containing lysozyme; 5) no processing of inactive pro-SleC into active SleC was observed in cspAC and cspC mutant spores during germination; and finally, 6) the defects in germination, DPA release, colony formation and SleC processing in cspAC and cspC mutant spores were complemented by the wild-type cspA-cspC operon. Collectively, these results indicate that both CspA and CspC are essential for C. perfringens spore germination through activating SleC and inducing cortex hydrolysis.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Clostridium perfringens/enzimologia , Esporos Bacterianos/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Clostridium perfringens/efeitos dos fármacos , Clostridium perfringens/genética , Clostridium perfringens/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Hidrólise , Óperon , Ácidos Picolínicos/farmacologia , Processamento de Proteína Pós-Traducional , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/enzimologia , Esporos Bacterianos/genética
10.
Int J Food Microbiol ; 316: 108418, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31877424

RESUMO

The aim of this study was to compare the sporicidal effect of the disinfectants peracetic acid (PAA) or hydrogen peroxide (H2O2) applied as a fog or as a liquid. The efficacy of fogging of the disinfectants was tested in a closed isolator cabinet using highly heat and chemical-resistant spores of Geobacillus stearothermophilus. Fogging of a 0.06% solution of PAA resulted in over 5-log reduction of spores in 10 min, whereas for PAA used in liquid form the same reduction was achieved in 4.5 min. The inactivation curves for fog and liquid were fitted using three different models (Linear with shoulder, Weibull, Gauss-Eyring). This showed a shoulder for the fog with an estimated length of 4.1 min, but the D values, calculated for the linear parts of the curves, were not significantly different (1.1 and 0.8 min for the PAA fog and solution, respectively). Similar results were obtained for a 12% H2O2 solution, albeit that H2O2 was less effective compared to PAA, requiring 60 min to reach 3-log reduction when applied as a fog, with an estimated shoulder of 18.5 min. Fogging of a 0.06% peracetic acid solution effectively inactivated G. stearothermophilus spores. Overall, the data show that fogging can be an effective method of applying disinfectants but that a shoulder in the inactivation curves should be considered in process design. This study provides inactivation kinetics for disinfection using PAA or H2O2-based fog, which can aid in selection and validation of process parameters for disinfection of contained areas by fogging.


Assuntos
Desinfetantes/farmacologia , Desinfecção/métodos , Geobacillus stearothermophilus/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Ácido Peracético/farmacologia , Aerossóis/farmacologia , Cinética , Esporos Bacterianos/efeitos dos fármacos
11.
Food Microbiol ; 85: 103285, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500704

RESUMO

The objective of this study was to determine the kinetic parameters and apply Markov Chain Monte Carlo (MCMC) simulation to predict the growth of Clostridium perfringens from spores in cooked ground chicken meat during dynamic cooling. Inoculated samples were exposed to various cooling conditions to observe dynamic growth. A combination of 4 cooling profiles was used in one-step inverse analysis with the Baranyi model as the primary model and the cardinal parameters model as the secondary model. Six kinetic parameters of the Baranyi model and the cardinal parameters model, including Q0, Ymax, µopt, Tmin, Topt, and Tmax, were estimated. The estimated Tmin, Topt, and Tmax were 14.8, 42.9, and 50.5 °C, respectively, with a µopt of 5.25 h-1 and maximum cell density of 8.4 log CFU/g. Correlation analysis showed that both Q0 and Ymax are weakly correlated to other parameters, while the remaining parameters are mostly mildly to strongly correlated with each other. Although it may be difficult to estimate highly correlated parameters using a single temperature profile, one-step analysis with multiple different temperature profiles helped estimate them successfully. The estimated parameters were used as the prior information to construct the posterior distribution for Bayesian analysis. MCMC simulation was used to predict the bacterial growth using different dynamic temperature profiles for validation of the accuracy of the predictive models. The MCMC simulation results showed that the Bayesian analysis produced more accurate predictions of bacterial growth during cooling than the deterministic method. With Bayesian analysis, the root-mean-square-error (RMSE) of prediction was only 0.1 log CFU/g with all residual errors within ±0.25 log CFU/g. Therefore, Bayesian analysis is recommended for predicting the growth of C. perfringens in cooked meat during cooling.


Assuntos
Clostridium perfringens/crescimento & desenvolvimento , Culinária , Manipulação de Alimentos , Produtos da Carne/microbiologia , Temperatura , Animais , Teorema de Bayes , Galinhas , Contagem de Colônia Microbiana , Simulação por Computador , Cinética , Cadeias de Markov , Modelos Biológicos , Método de Monte Carlo , Esporos Bacterianos/crescimento & desenvolvimento
12.
J Appl Microbiol ; 128(1): 124-137, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31573710

RESUMO

AIMS: To add a spore germination step in order to reduce decontamination temperature and time requirements compared to the current hot, humid air decontamination parameters, which are 75-80°C, ≥72 h, 70-90% RH, down to ≤60°C and ≤24 h total decontamination time. METHODS AND RESULTS: Bacillus anthracis spore germination with l-alanine+inosine+calcium dipicolinate (CaDPA) was quantified at 0-40°C, several time points and spore concentrations of 5-9 log10 per ml. Germination efficiency at 0-40°C was >99% at <8 log10 spores per ml. The temperature optimum was 20°C. Germination efficiency was significantly higher but slower at 0°C compared to ≥30°C at ≥8 log10 spores per ml. A single germinant application followed by 60°C, 1-h treatment consistently inactivated >2 log10 (>99%) of spores. However, a repeat application of germinant was needed to achieve the objective of ≥6 log10 spore inactivation out of a 7 log10 challenge (≥99·9999%) for ≤24 h total decontamination time for nylon and aircraft performance coating. CONCLUSIONS: l-alanine+inosine+CaDPA stimulated germination across wide temperature and spore concentration ranges. SIGNIFICANCE AND IMPACT OF THE STUDY: Germination expands the scope of spore decontamination to include materials from any industry sector that can be sprayed with an aqueous germinant solution.


Assuntos
Bacillus anthracis/fisiologia , Descontaminação/métodos , Esporos Bacterianos/fisiologia , Alanina/farmacologia , Bacillus anthracis/efeitos dos fármacos , Bacillus anthracis/crescimento & desenvolvimento , Temperatura Alta , Inosina/farmacologia , Ácidos Picolínicos/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/crescimento & desenvolvimento , Fatores de Tempo
13.
Int. microbiol ; 22(4): 511-520, dic. 2019. graf, tab
Artigo em Inglês | IBECS | ID: ibc-185069

RESUMO

The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway


No disponible


Assuntos
Poluentes do Solo/análise , Análise do Solo , Esporos Bacterianos/isolamento & purificação , Contagem de Colônia Microbiana , RNA Ribossômico 16S/genética , Bactérias Anaeróbias/isolamento & purificação , Bacillales/isolamento & purificação , Esporos Fúngicos/genética , Brasil , Bacillales/genética , Perfilação da Expressão Gênica/métodos
14.
Microbiol Spectr ; 7(6)2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31858953

RESUMO

As obligate anaerobes, clostridial pathogens depend on their metabolically dormant, oxygen-tolerant spore form to transmit disease. However, the molecular mechanisms by which those spores germinate to initiate infection and then form new spores to transmit infection remain poorly understood. While sporulation and germination have been well characterized in Bacillus subtilis and Bacillus anthracis, striking differences in the regulation of these processes have been observed between the bacilli and the clostridia, with even some conserved proteins exhibiting differences in their requirements and functions. Here, we review our current understanding of how clostridial pathogens, specifically Clostridium perfringens, Clostridium botulinum, and Clostridioides difficile, induce sporulation in response to environmental cues, assemble resistant spores, and germinate metabolically dormant spores in response to environmental cues. We also discuss the direct relationship between toxin production and spore formation in these pathogens.


Assuntos
Infecções por Clostridium/microbiologia , Clostridium/crescimento & desenvolvimento , Esporos Bacterianos/crescimento & desenvolvimento , Animais , Clostridium/classificação , Clostridium/genética , Clostridium/patogenicidade , Humanos , Esporos Bacterianos/classificação , Esporos Bacterianos/genética , Esporos Bacterianos/metabolismo
15.
Int J Food Microbiol ; 311: 108329, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31669928

RESUMO

This study evaluated the synergetic inhibitory effects of ultrasound and nisin/carvacrol on spore germination, outgrowth, and subsequent growth of vegetative cell of Bacillus subtilis in laboratory medium and milk. Ultrasound pretreatment (3.33 W/mL, 15 min) and nisin/carvacrol (0.01%, 0.02%) synergistically inhibited spore germination, outgrowth, and vegetative growth of spores in laboratory medium. Whereas no such inhibitory effect was observed in milk even with a 10-fold increase in the concentration (1%) of nisin. Flow cytometry analysis showed that the germination capacities of ultrasound pretreated spores combined with nisin/carvacrol (67.3% and 30.5%, respectively) was lower than that of the untreated spores (95.1%). These results quantitatively revealed the inhibitory effect of the combined treatments which were confirmed by phase-bright spore observations at single cell level. In general, the current work identified the combined ultrasound-carvacrol treatment as an effective strategy to control spores and vegetative cells of B. subtilis in the laboratory medium and milk during abusive storage.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Nisina/farmacologia , Esporos Bacterianos/crescimento & desenvolvimento , Animais , Sinergismo Farmacológico , Leite/microbiologia , Análise de Célula Única
16.
Elife ; 82019 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-31609203

RESUMO

The bacterium Myxococcus xanthus exhibits a complex multicellular life cycle. In the presence of nutrients, cells prey cooperatively. Upon starvation, they enter a developmental cycle wherein cells aggregate to produce macroscopic fruiting bodies filled with resistant myxospores. We used RNA-Seq technology to examine the transcriptome of the 96 hr developmental program. These data revealed that 1415 genes were sequentially expressed in 10 discrete modules, with expression peaking during aggregation, in the transition from aggregation to sporulation, or during sporulation. Analysis of genes expressed at each specific time point provided insights as to how starving cells obtain energy and precursors necessary for assembly of fruiting bodies and into developmental production of secondary metabolites. This study offers the first global view of developmental transcriptional profiles and provides important tools and resources for future studies.


Assuntos
Proteínas de Bactérias/genética , Myxococcus xanthus/genética , Transcriptoma/genética , Regulação Bacteriana da Expressão Gênica/genética , Transdução de Sinais/genética , Esporos Bacterianos/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-31590291

RESUMO

Background: A seasonal predictor of anthrax outbreaks is rainfall, which may be approximated by NDVI using remote sensing. How rainfall or vegetative green-up influences bacterial physiology or microecology to drive anthrax outbreaks is not known. Methods: Rainfall and NDVI dependency of anthrax epizootics was demonstrated with global and local phenological analysis. Growth analysis of B. anthracis in response to pH and calcium gradients was carried out. The influence of pH and calcium levels on expression of toxin and sporulation related proteins in broth culture models was characterized using engineered B. anthracis luminescent reporter strains. Results: Short-term bacterial growth and longer-term bacterial survival were altered by pH and calcium. These conditions also played a major role in pagA and sspB promoter-driven luminescent expression in B. anthracis. Conclusions: Rainfall induced cycling of pH and calcium in soils plays a plausible role in amplifying spore load and persistence in endemic anthrax zones. Observed evidence of B. anthracis favoring soil alkalinity and high soil calcium levels in the environment were linked to physiological conditions that promote bacterial growth, survival, toxin secretion and spore formation; illustrating the utility of bringing laboratory-based (controlled) microbiology experiments into the fold of zoonotic disease ecology.


Assuntos
Antraz/epidemiologia , Surtos de Doenças , Animais , Bacillus anthracis , Microbiologia do Solo , Esporos Bacterianos
18.
Curr Microbiol ; 76(12): 1487-1494, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31494740

RESUMO

Iturin A is a very important cyclic lipopeptide produced by several B. subtilis strains and has large commercial and therapeutic application potentials but its production on industrial scale has not been realized yet. In the present study, we have observed that the strain ET-1 of Bacillus subtilis, a producer of Iturin A, can present at least three different colony morphologies, which we arbitrarily called Rough, Smooth, and Mucoid morphotypes (R-, S-, and M-form). Performing HPLC analysis, a significant difference between the amounts of Iturin A produced by the three morphotypes was found. The morphotype R-form showed the highest productivity with yields about 10 and 100 times higher than morphotypes S and M, respectively. The results show that the production of Iturin A by B. subtilis could be strongly influenced by the phenotypic heterogeneity of cells within the inoculum. Indeed, we have observed that, pasteurizing the inoculum before seeding in order to improve the homogeneity removing the phenotypes less able to synthesize the Iturin A, its yields in a bench-scale production could be significantly improved. This can represent an important control factor also at industrial scale to improve the Iturin A yields, the robustness, the replicability, and consequently the cost-effectiveness of fermentation processes.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Peptídeos Cíclicos/biossíntese , Reatores Biológicos/microbiologia , Fermentação , Fenótipo , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Bacterianos/metabolismo
19.
Biosens Bioelectron ; 143: 111628, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476599

RESUMO

A combined calorimetric gas- and spore-based biosensor array is presented in this work to monitor and evaluate the sterilization efficacy of gaseous hydrogen peroxide in aseptic filling machines. H2O2 has been successfully measured under industrial conditions. Furthermore, the effect of H2O2 on three different spore strains , namely Bacillus atrophaeus, Bacillus subtilis and Geobacillus stearothermophilus, has been investigated by means of SEM, AFM and impedimetric measurements. In addition, the sterilization efficacy of a spore-based biosensor and the functioning principle are addressed and discussed: the sensor array is convenient to be used in aseptic food industry to guarantee sterile packages.


Assuntos
Técnicas Biossensoriais , Calorimetria , Peróxido de Hidrogênio/isolamento & purificação , Esporos Bacterianos/efeitos dos fármacos , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Desinfetantes/química , Desinfetantes/isolamento & purificação , Gases/química , Gases/isolamento & purificação , Geobacillus stearothermophilus/efeitos dos fármacos , Geobacillus stearothermophilus/crescimento & desenvolvimento , Humanos , Peróxido de Hidrogênio/farmacologia , Infertilidade , Esporos Bacterianos/crescimento & desenvolvimento , Esterilização
20.
Life Sci ; 235: 116839, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31499068

RESUMO

Cancer is one of the leading causes of human death worldwide. Conventional anticancer therapies are ineffective in treating cancer patients due to various reasons. Thus, more effective and accessible alternative anticancer strategies have been evolved with time with high specificity towards tumor cells and with less or no adverse effects to normal cells. One such promising therapy is the use of bacterial toxins and spores to treat advanced solid tumors. Initially, Coley paved the way towards the bacterial anticancer therapy several decades ago and now it has emerged as a potential tool to eliminate tumor cells. Bacterial spores of obligate anaerobes exclusively germinate in the hypoxic/necrotic areas and not in the well-oxygenated areas of the body. This unique phenomenon has been exploited in using bacterial spores as a remedy for cancer. Bacterial toxins also play a significant role in either directly killing tumor cells or altering the cellular processes of the tumor cells which ultimately leads to the inhibition and regression of the solid tumor. With the advancement of molecular techniques, a number of genetically-modified non-pathogenic bacteria have been developed to use in bacterial anticancer strategies. Although promising results have shown so far, further investigations are required to ensure the efficacy and the safety of the bacterial spores and toxins in treating cancer.


Assuntos
Toxinas Bacterianas/uso terapêutico , Neoplasias/terapia , Esporos Bacterianos , Humanos
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