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1.
BMC Plant Biol ; 21(1): 176, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33845762

RESUMO

BACKGROUND: Salinity is a major threat to the agriculture industry due to the negative impact of salinity stress on crop productivity. In the present study, we isolated rhizobacteria and evaluated their capacities to promote crop growth under salt stress conditions. RESULTS: We isolated rhizospheric bacteria from sand dune flora of Pohang beach, Korea, and screened them for plant growth-promoting (PGP) traits. Among 55 bacterial isolates, 14 produced indole-3-acetic acid (IAA), 10 produced siderophores, and 12 produced extracellular polymeric and phosphate solubilization. Based on these PGP traits, we selected 11 isolates to assess for salinity tolerance. Among them, ALT29 and ALT43 showed the highest tolerance to salinity stress. Next, we tested the culture filtrate of isolates ALT29 and ALT43 for IAA and organic acids to confirm the presence of these PGP products. To investigate the effects of ALT29 and ALT43 on salt tolerance in soybean, we grew seedlings in 0 mM, 80 mM, 160 mM, and 240 mM NaCl treatments, inoculating half with the bacterial isolates. Inoculation with ALT29 and ALT43 significantly increased shoot length (13%), root length (21%), shoot fresh and dry weight (44 and 35%), root fresh and dry weight (9%), chlorophyll content (16-24%), Chl a (8-43%), Chl b (13-46%), and carotenoid (14-39%) content of soybean grown under salt stress. Inoculation with ALT29 and ALT43 also significantly decreased endogenous ABA levels (0.77-fold) and increased endogenous SA contents (6-16%), increased total protein (10-20%) and glutathione contents, and reduced lipid peroxidation (0.8-5-fold), superoxide anion (21-68%), peroxidase (12.14-17.97%), and polyphenol oxidase (11.76-27.06%) contents in soybean under salinity stress. In addition, soybean treated with ALT29 and ALT43 exhibited higher K+ uptake (9.34-67.03%) and reduced Na+ content (2-4.5-fold). Genes involved in salt tolerance, GmFLD19 and GmNARK, were upregulated under NaCl stress; however, significant decreases in GmFLD19 (3-12-fold) and GmNARK (1.8-3.7-fold) expression were observed in bacterial inoculated plants. CONCLUSION: In conclusion, bacterial isolates ALT29 and ALT43 can mitigate salinity stress and increase plant growth, providing an eco-friendly approach for addressing saline conditions in agricultural production systems.


Assuntos
Fenômenos Fisiológicos Bacterianos , Estresse Salino , Tolerância ao Sal , Soja/crescimento & desenvolvimento , Soja/microbiologia , Antioxidantes/metabolismo , Bactérias/isolamento & purificação , Bactérias/metabolismo , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Potássio/metabolismo , Rizosfera , Tolerância ao Sal/genética , Sódio/metabolismo , Soja/genética , Soja/metabolismo
2.
Nat Commun ; 12(1): 1498, 2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33686084

RESUMO

Sugarcane ethanol fermentation represents a simple microbial community dominated by S. cerevisiae and co-occurring bacteria with a clearly defined functionality. In this study, we dissect the microbial interactions in sugarcane ethanol fermentation by combinatorically reconstituting every possible combination of species, comprising approximately 80% of the biodiversity in terms of relative abundance. Functional landscape analysis shows that higher-order interactions counterbalance the negative effect of pairwise interactions on ethanol yield. In addition, we find that Lactobacillus amylovorus improves the yeast growth rate and ethanol yield by cross-feeding acetaldehyde, as shown by flux balance analysis and laboratory experiments. Our results suggest that Lactobacillus amylovorus could be considered a beneficial bacterium with the potential to improve sugarcane ethanol fermentation yields by almost 3%. These data highlight the biotechnological importance of comprehensively studying microbial communities and could be extended to other microbial systems with relevance to human health and the environment.


Assuntos
Fenômenos Fisiológicos Bacterianos , Etanol/metabolismo , Fermentação , Interações Microbianas/fisiologia , Saccharomyces cerevisiae/fisiologia , Acetaldeído/metabolismo , Acetaldeído/farmacologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Biodiversidade , Microbiologia Industrial/métodos , Lactobacillus/metabolismo , Microbiota , Melaço , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharum
3.
Science ; 371(6536)2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33766858

RESUMO

Microbial roles in cancer formation, diagnosis, prognosis, and treatment have been disputed for centuries. Recent studies have provocatively claimed that bacteria, viruses, and/or fungi are pervasive among cancers, key actors in cancer immunotherapy, and engineerable to treat metastases. Despite these findings, the number of microbes known to directly cause carcinogenesis remains small. Critically evaluating and building frameworks for such evidence in light of modern cancer biology is an important task. In this Review, we delineate between causal and complicit roles of microbes in cancer and trace common themes of their influence through the host's immune system, herein defined as the immuno-oncology-microbiome axis. We further review evidence for intratumoral microbes and approaches that manipulate the host's gut or tumor microbiome while projecting the next phase of experimental discovery.


Assuntos
Fenômenos Fisiológicos Bacterianos , Microbiota , Neoplasias/microbiologia , Neoplasias/terapia , Imunidade Adaptativa , Antibacterianos/uso terapêutico , Antineoplásicos/uso terapêutico , Bactérias/genética , Carcinogênese , Microbioma Gastrointestinal , Engenharia Genética , Interações entre Hospedeiro e Microrganismos , Humanos , Imunomodulação , Imunoterapia , Tecido Linfoide/imunologia , Neoplasias/imunologia , Terapia Viral Oncolítica , Microambiente Tumoral , Fenômenos Fisiológicos Virais
4.
Int J Mol Sci ; 22(4)2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33668649

RESUMO

The solute/sodium symporter family (SSS family; TC 2.A.21; SLC5) consists of integral membrane proteins that use an existing sodium gradient to drive the uphill transport of various solutes, such as sugars, amino acids, vitamins, or ions across the membrane. This large family has representatives in all three kingdoms of life. The human sodium/iodide symporter (NIS) and the sodium/glucose transporter (SGLT1) are involved in diseases such as iodide transport defect or glucose-galactose malabsorption. Moreover, the bacterial sodium/proline symporter PutP and the sodium/sialic acid symporter SiaT play important roles in bacteria-host interactions. This review focuses on the physiological significance and structural and functional features of prokaryotic members of the SSS family. Special emphasis will be given to the roles and properties of proteins containing an SSS family domain fused to domains typically found in bacterial sensor kinases.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Bactérias/metabolismo , Fenômenos Fisiológicos Bacterianos , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Transportador 1 de Glucose-Sódio/metabolismo , Simportadores/metabolismo
5.
Science ; 371(6531)2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33602828

RESUMO

During 450 million years of diversification on land, plants and microbes have evolved together. This is reflected in today's continuum of associations, ranging from parasitism to mutualism. Through phylogenetics, cell biology, and reverse genetics extending beyond flowering plants into bryophytes, scientists have started to unravel the genetic basis and evolutionary trajectories of plant-microbe associations. Protection against pathogens and support of beneficial, symbiotic, microorganisms are sustained by a blend of conserved and clade-specific plant mechanisms evolving at different speeds. We propose that symbiosis consistently emerges from the co-option of protection mechanisms and general cell biology principles. Exploring and harnessing the diversity of molecular mechanisms used in nonflowering plant-microbe interactions may extend the possibilities for engineering symbiosis-competent and pathogen-resilient crops.


Assuntos
Fenômenos Fisiológicos Bacterianos , Evolução Biológica , Fungos/fisiologia , Interações entre Hospedeiro e Microrganismos , Plantas/genética , Simbiose , Bactérias/crescimento & desenvolvimento , Resistência à Doença , Fungos/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Imunidade Inata , Oomicetos/crescimento & desenvolvimento , Oomicetos/fisiologia , Filogenia , Doenças das Plantas , Reguladores de Crescimento de Planta/metabolismo , Plantas/metabolismo , Plantas/microbiologia , Transdução de Sinais
6.
Methods Mol Biol ; 2229: 267-291, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33405227

RESUMO

Heterologous gene expression draws resources from host cells. These resources include vital components to sustain growth and replication, and the resulting cellular burden is a widely recognized bottleneck in the design of robust circuits. In this tutorial we discuss the use of computational models that integrate gene circuits and the physiology of host cells. Through various use cases, we illustrate the power of host-circuit models to predict the impact of design parameters on both burden and circuit functionality. Our approach relies on a new generation of computational models for microbial growth that can flexibly accommodate resource bottlenecks encountered in gene circuit design. Adoption of this modeling paradigm can facilitate fast and robust design cycles in synthetic biology.


Assuntos
Bactérias/genética , Redes Reguladoras de Genes , Biologia de Sistemas/métodos , Fenômenos Fisiológicos Bacterianos , Proteínas de Bactérias/genética , Expressão Gênica , Genes Sintéticos , Modelos Biológicos , Biologia Sintética
7.
Appl Environ Microbiol ; 87(6)2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33419738

RESUMO

Escherichia coli cells swim in aqueous environment in a random walk of alternating runs and tumbles. The diffusion characteristics of this random walk remains unclear. In this study, by tracking the swimming of wild-type cells in a three-dimensional (3D) homogeneous environment, we found that their trajectories are superdiffusive, consistent with Lévy walk behavior. For comparison, we tracked the swimming of mutant cells that lack the chemotaxis signaling noise (the steady-state fluctuation of the concentration of the chemotaxis response regulator CheY-P) and found that their trajectories are normal diffusive. Therefore, wild-type E. coli cells explore the environment by Lévy walk, which originates from the chemotaxis signaling noise. This Lévy walk pattern enhances their efficiency in environmental exploration.IMPORTANCE E. coli cells explore the environment in a random walk of alternating runs and tumbles. By tracking the 3D trajectories of E. coli cells in an aqueous environment, we found that their trajectories are superdiffusive, with a power-law shape for the distribution of run lengths, which is characteristics of Lévy walk. We further show that this Lévy walk behavior is due to the random fluctuation of the output level of the bacterial chemotaxis pathway, and it enhances the efficiency of the bacteria in exploring the environment.


Assuntos
Quimiotaxia , Escherichia coli/fisiologia , Fenômenos Fisiológicos Bacterianos , Simulação por Computador
8.
Gene ; 774: 145425, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33450352

RESUMO

Corrosion in pipelines and reservoir tanks in oil plants is a serious problem in the global energy industry because it causes substantial economic losses associated with frequent part replacement and can lead to potential damage to entire crude oil fields. Previous studies revealed that corrosion is mainly caused by microbial activities in a process currently termed microbiologically influenced corrosion or biocorrosion. Identifying the bacteria responsible for biocorrosion is crucial for its suppression. In this study, we analyzed the microbial communities present at corrosion sites in oil plant pipelines using comparative metagenomic analysis along with bioinformatics and statistics. We analyzed the microbial communities in pipelines in an oil field in which groundwater is used as injection water. We collected samples from four different facilities in the oil field. Metagenomic analysis revealed that the microbial community structures greatly differed even among samples from the same facility. Treatments such as biocide administration and demineralization at each location in the pipeline may have independently affected the microbial community structure. The results indicated that microbial inspection throughout the pipeline network is essential to prevent biocorrosion at industrial plants. By identifying the bacterial species responsible for biocorrosion, this study provides bacterial indicators to detect and classify biocorrosion. Furthermore, these species may serve as biomarkers to detect biocorrosion at an early stage. Then, appropriate management such as treatment with suitable biocides can be performed immediately and appropriately. Thus, our study will serve as a platform for obtaining microbial information related to biocorrosion to enable the development of a practical approach to prevent its occurrence.


Assuntos
Fenômenos Fisiológicos Bacterianos , Corrosão , Campos de Petróleo e Gás/microbiologia , Microbiologia do Solo , Bactérias , Biodegradação Ambiental , Metagenômica , Microbiota
9.
Int J Food Microbiol ; 339: 109034, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33388710

RESUMO

Increasing consumer demand for high-quality foods has driven adoption by the food industry of non-thermal technologies such as high pressure processing (HPP). The technology is employed as a post-packaging treatment step for inactivation of vegetative microorganisms. In order to evaluate HPP inactivation of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in acid and acidified juices and beverages, pressure tolerance parameters were determined using log-linear and Weibull models in pH-adjusted apple juice (pH 4.5) at 5 °C. A commercial processing HPP unit was used. The Weibull model better described the inactivation kinetics of the three tested pathogens. According to estimates from the Weibull model, 1.5, 0.9, and 1.5 min are required at 600 MPa to produce 5-log reductions of E. coli, Salmonella, and L. monocytogenes, respectively, whereas according to the log-linear model, 3.2, 1.8, and 2.1 min are required. The effects of process conditions were verified using commercial products (pH between 3.02 and 4.21). In all tested commercial juices or beverages, greater than 5-log reductions were achieved for all tested pathogens using HPP process conditions of 550 MPa for 1 min. These findings demonstrate that the HPP conditions of 600 MPa for 3 min, typically used by the food industry provide an adequate safety margin for control of relevant vegetative pathogens in acid and acidified juices and beverages (pH < 4.5). Results from this study can be used by food processors to support validation studies and may be useful for the future establishment of safe harbors for the HPP industry.


Assuntos
Fenômenos Fisiológicos Bacterianos , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Sucos de Frutas e Vegetais , Viabilidade Microbiana , Pressão , Ácidos , Bebidas/microbiologia , Contagem de Colônia Microbiana , Escherichia coli O157/fisiologia , Manipulação de Alimentos/normas , Sucos de Frutas e Vegetais/microbiologia , Listeria monocytogenes/fisiologia , Malus/microbiologia , Salmonella enterica/fisiologia
10.
Appl Environ Microbiol ; 87(6)2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33452019

RESUMO

Photosynthetic cave communities ("lampenflora") proliferate in Carlsbad Cavern and other show caves worldwide due to artificial lighting. These biofilms mar the esthetics and can degrade underlying cave surfaces. The National Park Service recently modernized the lighting in Carlsbad Cavern to a light-emitting diode (LED) system that allows adjustment of the color temperature and intensity. We hypothesized that lowering the color temperature would reduce photopigment development. We therefore assessed lampenflora responses to changes in lighting by monitoring photosynthetic communities over the course of a year. We measured photopigments using reflected-light spectrophotometric observations and analyzed microbial community composition with 16S and 18S rRNA gene amplicon sequencing. Reflected-light spectrophotometry revealed that photosynthetic biofilm development is affected by lighting intensity, color temperature, substrate type, and cleaning of the substrate. Gene sequencing showed that the most abundant phototrophs were Cyanobacteria and members of the algal phyla Chlorophyta and Ochrophyta At the end of the study, visible growth of lampenflora was seen at all sites. At sites that had no established biofilm at the start of the study period, Cyanobacteria became abundant and outpaced an increase in eukaryotic algae. Microbial diversity also increased over time at these sites, suggesting a possible pattern of early colonization and succession. Bacterial community structure showed significant effects of all variables: color temperature, light intensity, substrate type, site, and previous cleaning of the substrate. These findings provide fundamental information that can inform management practices; they suggest that altering lighting conditions alone may be insufficient to prevent lampenflora growth.IMPORTANCE Artificial lighting in caves visited by tourists ("show caves") can stimulate photosynthetic algae and cyanobacteria, called "lampenflora," which are unsightly and damage speleothems and other cave surfaces. The most common mitigation strategy employs bleach, but altering intensities and wavelengths of light might be effective and less harsh. Carlsbad Cavern in New Mexico, a U.S. National Park and UNESCO World Heritage Site, has visible lampenflora despite adjustment of LED lamps to decrease the energetic blue light. This study characterized the lampenflora communities and tested the effects of color temperature, light intensity, rock or sediment texture, and time on lampenflora development. DNA amplicon sequence data show a variety of algae and cyanobacteria and also heterotrophic bacteria. This study reveals microbial dynamics during colonization of artificially lit surfaces and indicates that while lowering the color temperature may have an effect, management of lampenflora will likely require additional chemical or UV treatment.


Assuntos
Biofilmes , Cavernas/microbiologia , Iluminação , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Microbiota , New Mexico , Parques Recreativos , Fotossíntese , Filogenia , RNA Ribossômico 16S
11.
Int J Food Microbiol ; 339: 108987, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33321431

RESUMO

Bacterial and fungal population dynamics in cider for distillation have so far been explored by culture-dependant methods. Cider for distillation can be produced by the spontaneous fermentation of apples that do not undergo any intervention during the process. In this study, cider microbiomes extracted from six tanks containing ciders for distillation from four producers in Normandy were characterized at three main stages of the fermentation process: fermentation Initiation (I), end of the alcoholic Fermentation (F) and end of the Maturation period (M). Cider samples were subjected to Illumina MiSeq sequencing (rRNA 16S V1-V3 and ITS1 region targeting) to determine bacterial and fungal communities. Yeasts (YGC), Zymomonas (mZPP) and lactic acid bacteria selective media (mMRS, mMLO, mPSM) were also used to collect 807 isolates. Alcoholic levels, glycerol, sugar content (glucose, fructose and sucrose), pH, total and volatile acidity, nitrogen, malic and lactic acid contents were determined at all sampling points. Alpha diversity indexes show significant differences (p < 0.05) in microbial populations between I, F and M. Fungal communities were characterized by microorganisms from the environment and phytopathogens at I followed by the association of yearsts with alcoholic fermentation like Saccharomyces and non-Saccharomyces yeasts (Hanseniaspora, Candida). A maturation period for cider leads to an increase of the Dekkera/Brettanomyces population, which is responsible for off-flavors in cider for all producers. Among bacterial communities, the genera community associated to malolactic fermentation (Lactobacillus sp., Leuconostoc sp., Oenococcus sp.) was the most abundant at F and M. Acetic acid bacteria such as Acetobacter sp., Komagataeibacter sp. and Gluconobacter sp. were also detected during the process. Significant differences (p < 0.05) were found in fungal and bacterial populations between the four producers and during the fermentation process. The development of microorganisms associated with cider spoilage such as Zymomonas mobilis, Lactobacillus collinoides or Brettanomyces/Dekkera sp. was anticipated by a metagenomic approach. The monitoring of microbial diversity via high throughput sequencing combined with physical-chemical analysis is an interesting approach to improve the fermentation performance of cider for distillation and therefore, the quality of Calvados.


Assuntos
Bebidas Alcoólicas/microbiologia , Fenômenos Fisiológicos Bacterianos , Biodiversidade , Destilação , Fungos/fisiologia , Bactérias/genética , DNA Espaçador Ribossômico/genética , Fermentação , Malus , RNA Ribossômico 16S/genética
12.
Nat Rev Microbiol ; 19(1): 8-22, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32807981

RESUMO

Antibiotic resistance is a global human health threat, causing routine treatments of bacterial infections to become increasingly difficult. The problem is exacerbated by biofilm formation by bacterial pathogens on the surfaces of indwelling medical and dental devices that facilitate high levels of tolerance to antibiotics. The development of new antibacterial nanostructured surfaces shows excellent prospects for application in medicine as next-generation biomaterials. The physico-mechanical interactions between these nanostructured surfaces and bacteria lead to bacterial killing or prevention of bacterial attachment and subsequent biofilm formation, and thus are promising in circumventing bacterial infections. This Review explores the impact of surface roughness on the nanoscale in preventing bacterial colonization of synthetic materials and categorizes the different mechanisms by which various surface nanopatterns exert the necessary physico-mechanical forces on the bacterial cell membrane that will ultimately result in cell death.


Assuntos
Antibacterianos/farmacologia , Infecções Bacterianas/microbiologia , Fenômenos Fisiológicos Bacterianos , Biofilmes/efeitos dos fármacos , Fenômenos Mecânicos , Nanoestruturas , Aderência Bacteriana , Infecções Bacterianas/tratamento farmacológico , Biofilmes/crescimento & desenvolvimento , Membrana Celular/ultraestrutura , Humanos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Propriedades de Superfície
13.
Am J Med Sci ; 361(3): 352-357, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33309136

RESUMO

BACKGROUND: Multi-drug resistant organisms have been emerging among kidney transplant (KT) recipients with bloodstream infections (BSI). The investigation for epidemiology, risk factors and outcome of these infections following KT was initiated. MATERIALS AND METHODS: A retrospective study of all adult KT recipients who developed a BSI within the first year after KT in 2016 at a single transplant center was conducted. The cumulative incidence of BSI was estimated with Kaplan-Meier methodology. Clinical characteristics and outcome were extracted. Risk factors were analyzed with Cox proportional hazards models. RESULTS: Among 171 KT recipients, there were 26 (15.2%) episodes of BSI. Fifty-nine percent were men and the mean ± SD age was 43 ± 12 years. The cumulative incidence of BSIs was 10.1% at 1 month, 13.5% at 6 months, and 15.2% at 12 months. Gram-negative bacteria were responsible for 92% of BSIs, Escherichia coli was the most common pathogen (65%) followed by Klebsiella pneumoniae (11%). Among those, 71% were resistant to extended-spectrum cephalosporins. The genitourinary tracts were the predominant source of BSIs (85%). The second kidney transplantation (HR, 4.55; 95% CI, 1.24-16.79 [P = 0.02]) and receiving induction therapy (HR, 3.05; 95% CI, 1.15-8.10 [P < 0.03]) were associated with BSI in a multivariate analysis. One patient (4%) developed allograft rejection, allograft failure and death from septic shock. CONCLUSIONS: One out of six KT recipients could develop BSI from gram-negative bacteria within the first year after transplant, particularly in those that received the second transplantation or induction therapy.


Assuntos
Fenômenos Fisiológicos Bacterianos , Farmacorresistência Bacteriana Múltipla , Transplante de Rim/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Sepse/epidemiologia , Adulto , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/microbiologia , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Sepse/tratamento farmacológico , Sepse/microbiologia , Tailândia/epidemiologia , Resultado do Tratamento
14.
Int J Food Microbiol ; 337: 108928, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33152572

RESUMO

Sponges are frequently used in kitchens and have been shown to harbor large numbers of bacteria, occasionally also pathogens. Less is known about kitchen brushes regarding usage and presence of bacteria. In the present study, the use of sponges and brushes was studied in a survey among 9966 European consumers in ten countries, and growth and survival of bacteria in sponges and brushes were examined in laboratory experiments. Sponges were the preferred hand-cleaning utensils for washing-up in the majority of countries, while brushes were most frequently used in Denmark and Norway. Consumers mostly change their sponges at regular times, but also sensory cues (looks dirty, smelly, slimy) and usage occurrences such as wiping up meat juices may trigger replacement. Besides cleaning the dishes, over a quarter of the dish brush users also use it to clean a chopping board after soilage from chicken meat juices. The water uptake and drying rate varied considerably, both between different sponges and between brushes and sponges, where brushes dried fastest. Campylobacter survived one day in all sponges and Salmonella more than seven days in two of three types of sponges. In the type of sponge that dried slowest, Salmonella grew on the first day and was always found in higher levels than in the other sponges. Non-pathogenic bacteria grew in the sponges and reached levels around 9 log CFU/sponge. In brushes all types of bacteria died over time. Campylobacter and Salmonella were reduced by more than 2.5 log to below the detection limit after one and three days, respectively. Bacteriota studies revealed a tendency for a dominance by Gram-negative bacteria and a shift to high relative prevalence of Pseudomonas over time in sponges. Both enumeration by agar plating and bacteriota analysis confirmed that the pathogens were in a minority compared to the other bacteria. Treatments of sponges and brushes with chlorine, boiling or in the dishwasher were effective to reduce Salmonella. We conclude that brushes are more hygienic than sponges and that their use should be encouraged. Contaminated sponges or brushes should be replaced or cleaned when they may have been in contact with pathogenic microorganisms, e.g. used on raw food spills. Cleaning of sponges and brushes with chlorine, boiling or dishwasher may be a safe alternative to replacing them with new ones.


Assuntos
Fenômenos Fisiológicos Bacterianos , Contaminação de Equipamentos/estatística & dados numéricos , Produtos Domésticos/microbiologia , Animais , Bactérias/isolamento & purificação , Campylobacter/fisiologia , Cloro , Contagem de Colônia Microbiana , Comportamento do Consumidor , Utensílios de Alimentação e Culinária , Europa (Continente) , Manipulação de Alimentos , Higiene/normas , Carne/microbiologia , Salmonella/fisiologia , Fatores de Tempo
15.
Poult Sci ; 100(1): 263-272, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357690

RESUMO

The aim of the research was to estimate the effect of selected lactic acid bacterial strains on the technological quality and microbiological stability of mechanically separated poultry meat (MSPM) cured with a reduced amount of sodium nitrite. The 5 different treatments of MSPM batters were prepared: C150 - control cured with sodium nitrite at 150 mg/kg, C50 - control cured with sodium nitrite at 50 mg/kg, PL1 - cured with sodium nitrite at 50 mg/kg and inoculated Lactobacillus plantarum SCH1 at about 107 cfu/g, PL2 - cured with sodium nitrite at 50 mg/kg and inoculated Lactobacillus brevis KL5 at about 107 cfu/g, and PL3 - cured sodium nitrite at 50 mg/kg and inoculated L. plantarum S21 at about 107 cfu/g. The MSPM batters were tested at 1, 4 and 7 d of being in refrigerated storage. The scope of the research was as follows - physicochemical determinations: pH and redox, nitrates and nitrites as well as nitrosyl pigments levels, color estimation with a Comission Internationale de l'Eclairage Lab system and microbiological determinations: the total viable counts, the mesophilic lactic acid bacteria counts, Escherichia coli and Enterobacteriaceae counts. The inhibitory effect of L. plantarum SCH1 isolated from the ecological raw fermented meat product on E. coli in cured MSPM batters during refrigerated storage was proved (P < 0.05). The use of lactic acid bacterial strains in cured batters that were prepared and based on mechanically separated poultry meat did not have a negative effect on their technological quality. The positive effect of L. brevis KL5 on the level of nitrosyl pigments in the cured MSPM batters was observed (P < 0.05). The conducted research suggested the possibility of using the selected bacterial strains of the Lactobacillus genus to improve the microbiological quality of MSPM cured with a reduced amount of sodium nitrite.


Assuntos
Antibiose , Fenômenos Fisiológicos Bacterianos , Microbiologia de Alimentos , Lactobacillales , Produtos da Carne , Nitrito de Sódio , Animais , Bactérias/efeitos dos fármacos , Carga Bacteriana , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Microbiologia de Alimentos/normas , Ácido Láctico , Lactobacillales/fisiologia , Produtos da Carne/análise , Produtos da Carne/microbiologia , Produtos da Carne/normas , Aves Domésticas , Nitrito de Sódio/farmacologia
16.
PLoS One ; 15(12): e0243315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33326455

RESUMO

Chronic rhinosinusitis (CRS) is a chronic disease that involves long-term inflammation of the nasal cavity and paranasal sinuses. Bacterial biofilms present on the sinus mucosa of certain patients reportedly exhibit resistance against traditional antibiotics, as evidenced by relapse, resulting in severe disease. The aim of this study was to determine the killing activity of human cathelicidin antimicrobial peptides (LL-37, LL-31) and their D-enantiomers (D-LL-37, D-LL-31), alone and in combination with conventional antibiotics (amoxicillin; AMX and tobramycin; TOB), against bacteria grown as biofilm, and to investigate the biological activities of the peptides on human lung epithelial cells. D-LL-31 was the most effective peptide against bacteria under biofilm-stimulating conditions based on IC50 values. The synergistic effect of D-LL-31 with AMX and TOB decreased the IC50 values of antibiotics by 16-fold and could eliminate the biofilm matrix in all tested bacterial strains. D-LL-31 did not cause cytotoxic effects in A549 cells at 25 µM after 24 h of incubation. Moreover, a cytokine array indicated that there was no significant induction of the cytokines involving in immunopathogenesis of CRS in the presence of D-LL-31. However, a tissue-remodeling-associated protein was observed that may prevent the progression of nasal polyposis in CRS patients. Therefore, a combination of D-LL-31 with AMX or TOB may improve the efficacy of currently used antibiotics to kill biofilm-embedded bacteria and eliminate the biofilm matrix. This combination might be clinically applicable for treatment of patients with biofilm-associated CRS.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/crescimento & desenvolvimento , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Células Epiteliais/microbiologia , Pulmão/microbiologia , Rinite , Sinusite , Células A549 , Adolescente , Adulto , Idoso , Biofilmes/crescimento & desenvolvimento , Doença Crônica , Células Epiteliais/metabolismo , Feminino , Humanos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Pessoa de Meia-Idade , Rinite/tratamento farmacológico , Rinite/microbiologia , Rinite/patologia , Sinusite/tratamento farmacológico , Sinusite/microbiologia , Sinusite/patologia
17.
Nat Commun ; 11(1): 5365, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097711

RESUMO

Whereas self-propelled hard discs undergo motility-induced phase separation, self-propelled rods exhibit a variety of nonequilibrium phenomena, including clustering, collective motion, and spatio-temporal chaos. In this work, we present a theoretical framework representing active particles by continuum fields. This concept combines the simplicity of alignment-based models, enabling analytical studies, and realistic models that incorporate the shape of self-propelled objects explicitly. By varying particle shape from circular to ellipsoidal, we show how nonequilibrium stresses acting among self-propelled rods destabilize motility-induced phase separation and facilitate orientational ordering, thereby connecting the realms of scalar and vectorial active matter. Though the interaction potential is strictly apolar, both, polar and nematic order may emerge and even coexist. Accordingly, the symmetry of ordered states is a dynamical property in active matter. The presented framework may represent various systems including bacterial colonies, cytoskeletal extracts, or shaken granular media.


Assuntos
Fenômenos Fisiológicos Bacterianos , Movimento (Física) , Análise por Conglomerados , Simulação por Computador , Modelos Biológicos , Modelos Teóricos , Movimento/fisiologia , Termodinâmica
18.
Proc Natl Acad Sci U S A ; 117(41): 25445-25454, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-32999067

RESUMO

Allostery is a fundamental regulatory mechanism of protein function. Despite notable advances, understanding the molecular determinants of allostery remains an elusive goal. Our current knowledge of allostery is principally shaped by a structure-centric view, which makes it difficult to understand the decentralized character of allostery. We present a function-centric approach using deep mutational scanning to elucidate the molecular basis and underlying functional landscape of allostery. We show that allosteric signaling exhibits a high degree of functional plasticity and redundancy through myriad mutational pathways. Residues critical for allosteric signaling are surprisingly poorly conserved while those required for structural integrity are highly conserved, suggesting evolutionary pressure to preserve fold over function. Our results suggest multiple solutions to the thermodynamic conditions of cooperativity, in contrast to the common view of a finely tuned allosteric residue network maintained under selection.


Assuntos
Adaptação Fisiológica , Regulação Alostérica/genética , Bactérias/citologia , Fenômenos Fisiológicos Bacterianos , Evolução Biológica , Clonagem Molecular , Epigênese Genética , Citometria de Fluxo , Regulação Enzimológica da Expressão Gênica , Modelos Moleculares , Simulação de Dinâmica Molecular , Mutação , Conformação Proteica
20.
PLoS Negl Trop Dis ; 14(9): e0008397, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32970667

RESUMO

BACKGROUND: Mycetoma, a chronic infection of the skin and underlying structures, affects those with a close relationship to the land, often in resource-poor areas of the world. Whether caused by any one of a variety of fungus or bacteria, mycetoma causes significant disability and mortality. Acknowledged as a neglected tropical disease (NTD) by the World Health Organization (WHO) in 2016, mycetoma is susceptible to being misunderstood, misdiagnosed, and mismanaged. In an effort to shift the balance in favor of recognition and effective treatment, sound epidemiological understanding is required. METHODS AND FINDINGS: In this paper, a literature review of case reports and series (332 papers in total) is presented as three maps. We identified 19,494 cases dating from 1876 to 2019, with cases contracted in 102 countries. The first map shows where mycetoma has ever been reported, the second shows how many cases have been reported, and the third shows the ratio of eumycetoma (fungal) to actinomycetoma (bacterial). Most cases are found in Mexico, India, and Sudan, where mycetoma is studied rigorously. We identified emergence of new geographical loci, including the United States, Venezuela, Italy, China, and Australia. Notably, mycetoma is reported far outside the tropics. In the Americas, bacterial forms dominate, whereas, in Africa and Asia, the picture is more varied. CONCLUSIONS: With better understanding of the epidemiology of mycetoma, more can be done to direct education, preventive measures, and treatment to at-risk areas, enabling a reduction in disease burden.


Assuntos
Micetoma/epidemiologia , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Fungos/genética , Fungos/isolamento & purificação , Fungos/fisiologia , Saúde Global , Humanos , Micetoma/diagnóstico , Micetoma/microbiologia
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