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1.
World J Microbiol Biotechnol ; 36(3): 50, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32157464

RESUMO

Despite the deep knowledge of the honey bee (Apis mellifera) gut microbiome, information on the microbial communities of other hive components is still scarce. Propolis originates from a natural resinous mixture that honeybees collect from different plants sources and modify; it is used mainly to ensure the hygiene of the hive. By virtue of its antimicrobial properties, propolis has been considered relatively aseptic, yet its ability to harbor microorganisms has not been previously investigated. In this study we report the first description of the diversity of the microbial community of propolis by both targeted-metagenomics analysis and cultivation. We demonstrated that propolis hosts a variety of microbial strains belonging to taxa already described in other hive components. Some of them are cultivable in standard laboratory conditions, and show metabolic characteristics compatible with their persistence in different physiological states inside propolis. Isolated bacteria produce antimicrobials against Gram-negative and Gram-positive bacteria, and entomopathogenic fungi, with different spectra of inhibition. Metagenomics analysis shows the presence of bacteria and fungi with great potential to outcompete potentially harmful microorganisms. These findings suggest that the characterized microbiota could contribute to the overall antimicrobial properties of propolis and to its ecological role as "disinfectant" within the hive.


Assuntos
Bactérias/classificação , Fungos/classificação , Microbiota , Própole/farmacologia , Animais , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Abelhas , DNA Ribossômico/genética , Fungos/efeitos dos fármacos , Fungos/isolamento & purificação , Microbioma Gastrointestinal , Testes de Sensibilidade Microbiana , Microbiota/efeitos dos fármacos , Filogenia
2.
Microbes Environ ; 35(1)2020.
Artigo em Inglês | MEDLINE | ID: mdl-31996500

RESUMO

Recent studies demonstrated that phylogenetically more diverse and abundant bacteria and fungi than previously considered are responsible for denitrification in terrestrial environments. We herein examined the effects of land-use types on the community composition of those denitrifying microbes based on their nitrite reductase gene (nirK and nirS) sequences. These genes can be phylogenetically grouped into several clusters. We used cluster-specific PCR primers to amplify nirK and nirS belonging to each cluster because the most widely used primers only amplify genes belonging to a single cluster. We found that the dominant taxa as well as overall community composition of denitrifying bacteria and fungi, regardless of the cluster they belonged to, differed according to the land-use type. We also identified distinguishing taxa based on individual land-use types, the distribution of which has not previously been characterized, such as denitrifying bacteria or fungi dominant in forest soils, Rhodanobacter having nirK, Penicillium having nirK, and Bradyrhizobium having nirS. These results suggest that land-use management affects the ecological constraints and consequences of denitrification in terrestrial environments through the assembly of distinct communities of denitrifiers.


Assuntos
Bactérias/classificação , Bactérias/metabolismo , Biodiversidade , Fungos/classificação , Fungos/metabolismo , Microbiota , Microbiologia do Solo , Bactérias/genética , Bactérias/isolamento & purificação , Desnitrificação , Fungos/genética , Fungos/isolamento & purificação , Genes Bacterianos , Genes Fúngicos , Nitrito Redutases/genética , Filogenia
3.
Food Microbiol ; 87: 103358, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948613

RESUMO

Microbes influence the quality of agricultural commodities and contribute to their distinctive sensorial attributes. Increasingly studies have demonstrated not only differential geographic patterns in microbial communities and populations, but that these contribute to valuable regionally distinct agricultural product identities, the most well-known example being wine. However, little is understood about microbial geographic patterns at scales of less than 100 km. For wine, single vineyards are the smallest (and most valuable) scale at which wine is asserted to differ; however, it is unknown whether microbes play any role in agricultural produce differentiation at this scale. Here we investigate whether vineyard fungal communities and yeast populations driving the spontaneous fermentation of fruit from these same vineyards are differentiated using metagenomics and population genetics. Significant differentiation of fungal communities was revealed between four Central Otago (New Zealand) Pinot Noir vineyard sites. However, there was no vineyard demarcation between fermenting populations of S. cerevisiae. Overall, this provides evidence that vineyard microbiomes potentially contribute to vineyard specific attributes in wine. Understanding the scale at which microbial communities are differentiated, and how these communities influence food product attributes has direct economic implications for industry and could inform sustainable management practices that maintain and enhance microbial diversity.


Assuntos
Fungos/isolamento & purificação , Micobioma , Vitis/microbiologia , Vinho/análise , Análise Discriminante , Fermentação , Frutas/microbiologia , Fungos/classificação , Fungos/genética , Nova Zelândia , Vinho/microbiologia
4.
Food Microbiol ; 87: 103378, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948619

RESUMO

Rice is one of the most consumed cereals in Brazil and around the world. Due to the major health impact of rice consumption on populations, studies about its quality have great importance. The present study determined the mycobiota of soil, field, processing and market rice samples from two production systems in Brazil, dryland in the state of Maranhão and wetland in the state of Rio Grande do Sul. These areas are distinct agroclimatic zones. A total of 171 rice and 23 soil samples were analyzed. A high differentiation was observed in the composition of the fungal communities found in the two production systems, as the wetland presented greater fungal incidence and biodiversity. It was observed that toxigenic species from Aspergillus section Flavi and Fusarium, present in the field, may infect rice grains pre or postharvest and may persist into the final product.


Assuntos
Fungos/isolamento & purificação , Micobioma , Oryza/microbiologia , Microbiologia do Solo , Biodiversidade , Brasil , Contaminação de Alimentos/análise , Fungos/classificação , Fungos/genética , Oryza/crescimento & desenvolvimento , Sementes/microbiologia
5.
Environ Monit Assess ; 192(2): 87, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900675

RESUMO

Exposure to outside air microorganisms especially fungi has been linked with illness such as allergic respiratory symptoms, rhinitis, asthma, and infection such as mycosis. Airborne fungal composition was sampled from five locations in Lagos State, Nigeria, between May 2014 and April 2016. Fungi spores were collected using the sedimentation plate method with the Petri dishes of dichloran-glycerol 18 (DG-18) and potato dextrose agar (PDA) media. Fungi sporulated faster on DG-18 agar plate as compared with PDA. The abundances of fungal spores collected monthly at the locations varied. The most abundant spores came from the fungi were Aspergillus niger (14.47%), Aspergillus sydowii (10.37%), and Aspergillus flavus (7.93%). Additional species were present in the collections including Ascomycetes: Penicillium funiculosum (5.49%), Neurospora crassa (5.32%), Penicillium oxalicum (4.71%), Penicillium pinophilum (2.88%), Fusarium verticillioides (3.05%), Penicillium simplicissimum (1.83%), Aphaderanum sp. (0.22%), Curvularia sp. (0.22%), Aspergillus oryzae (0.22%), and Paecilomyces sp. (0.61%) and the Mucoromycotina Zygomycetes: Rhizopus oryzae (4.10%) and Mucor sp. (3.44%). Fungal concentrations were significantly higher (P ≤ 0.05) during the rainy season compared with the dry season. Aspergillus and Penicillium were the most predominant airborne fungal genera while Mucor, Alternaria, and Cladosporium were some of the least observed. Generally, abundance of fungi was significantly high during the wet season in all the studied locations.


Assuntos
Microbiologia do Ar , Monitoramento Ambiental , Esporos Fúngicos , Alérgenos , Alternaria , Aspergillus , Asma , Cladosporium , Fungos/classificação , Hipersensibilidade , Nigéria , Penicillium , Estações do Ano
6.
J Agric Food Chem ; 68(5): 1226-1236, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31922739

RESUMO

As a substitute for methyl bromide, effects of allyl isothiocyanate (AITC) on nontarget microorganisms in soil are poorly understood. This study measured the half-life of AITC in the soil as well as its effects on the soil substrate-induced respiration (SIR) and on communities of soil bacteria and fungi. The results showed that AITC had a short half-life and a short-term inhibition of SIR; high-throughput sequencing analysis showed that AITC had less effect on bacterial than fungal communities. Fumigation reduced the diversity of soil bacteria temporarily, but stimulated the diversity of soil fungi in the long-term and significantly changed the structure of the fungal community. Following AITC fumigation there were significant increases in the relative abundance of probiotics such as Sphingomonas, Streptomyces, Hypocreales, Acremonium, Aspergillus, and Pseudallescheria that help to control plant diseases. Our study provided useful information for assessing the ecological safety of AITC.


Assuntos
Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Isotiocianatos/farmacologia , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Fumigação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Isotiocianatos/química , Lycopersicon esculentum/crescimento & desenvolvimento , Solo/química
7.
BMC Infect Dis ; 20(1): 8, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906848

RESUMO

BACKGROUND: There have been no systematic studies of microbiological differences before and after antibiotics treatment. The aim of this study was to evaluate the effect of prior receipt of antibiotics on the microorganism distribution. METHODS: A retrospective, observational cohort study was conducted in a 3200-bed tertiary, referral, teaching hospital in eastern China. During a 2-year period, all hospitalized patients treated with antimicrobial agents were enrolled in this study. Among 48,692 patients evaluated, the 27,792 (57.1%) who were sampled within 2 days before or after administration of the first dose of antimicrobial agents were included. Distribution of clinical specimens and the microorganism were compared between before and after antibiotic drug treatment groups. RESULTS: Compared to specimens taken after antibiotics exposure, specimens taken before antibiotics exposure had a higher proportion of blood and urine specimens and a higher culture positive rate (all P < 0.001). Higher percentages of Staphylococcus aureus (9.9% vs. 8.5%, P = 0.041), non-fermenting bacteria (27.7% vs. 19.9%, P < 0.001), and fungi (8.4% vs. 4.0%, P < 0.001) were isolated from the group after antibiotics exposure, while the percentages of Streptococcus spp. (4.8% vs. 2.7%, P < 0.001), Haemophilus influenzae (2.3% vs. 0.8%, P < 0.001), and Moraxella catarrhalis (0.7% vs. 0.1%, P < 0.001) were higher in the group before antibiotics exposure. Further analysis found significant differences of microbes derived from respiratory secretions, blood or urine samples. We found, after antibiotics exposure, the separation rate of non-fermenting bacteria was significantly increased (all P < 0.05), and the separation rate of Candida spp. was higher, with statistical significance in airway secretion and urine samples (both P < 0.05), but the separation rate of Staphylococcus aureus among the three groups was not affected by antibiotics. In addition, the isolation rate of Streptococcus spp. in blood and urine samples decreased significantly (both P < 0.05) after antibiotics exposure. Interestingly, no statistical difference was found for microbes isolated from body fluid specimens between the two groups. CONCLUSIONS: The outcome revealed that antibiotic-insensitive organisms such as non-fermentative bacteria and fungi were more frequently isolated after antibiotics exposure. However, this trend might be specimen dependent and was not obvious in body fluid specimens.


Assuntos
Antibacterianos/uso terapêutico , Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Idoso , Antibacterianos/efeitos adversos , Antibacterianos/farmacologia , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , China , Feminino , Fungos/classificação , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
8.
J Sci Food Agric ; 100(4): 1448-1457, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31756265

RESUMO

BACKGROUND: Baixi sufu (BS) is a traditional Chinese spicy fermented bean curd manufactured with a natural starter. In this study, the bacterial and fungal communities during BS fermentation were determined by culture and by the culture-independent method of high-throughput sequencing (HTS). Correlation analyses were performed to select the microorganisms potentially contributing to this fermentation. RESULTS: During the fermentation of BS, 162 bacterial and 97 fungal strains were isolated and identified, and a total of 268 314 bacterial and 287 844 fungal high-quality sequences were analyzed. In general, lactic acid bacteria (LAB), especially Enterococcus and Lactococcus, were dominant in the early stage of fermentation, and spore-forming bacteria, especially Bacillus spp., became the predominant bacteria by the end of fermentation. Geotrichum, Mortierella, and unclassified Ascomycota, were the major fungal populations, which could not be detected in the final product. Correlation analyses indicated that Enterococcus, Bacillus, Geotrichum, and unclassified Ascomycota correlated significantly and positively with amino nitrogen. However, due to the sporulation characteristics of Bacillus, they may have little effect on BS ripening. The presence of Bifidobacterium spp. in sufu is reported for the first time, but the excessive counts of the Bacillus cereus group (>105 CFU g-1 ) indicate a potential hazard to consumers. CONCLUSION: The profiles obtained from this study will contribute to the development of autochthonous starter cultures to control BS fermentation, and may lead to the development of novel strategies to shorten the fermentation time of sufu products. © 2019 Society of Chemical Industry.


Assuntos
Fabaceae/microbiologia , Fungos/metabolismo , Lactobacillales/metabolismo , Micobioma , Fabaceae/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação
9.
J Appl Microbiol ; 128(1): 209-224, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31559682

RESUMO

AIMS: The work investigates the impact of grapes processing at the beginning of winemaking on the composition of microbiota during the oenological fermentations and on the composition of obtained wines. METHODS AND RESULTS: The experiments were conducted in a biodynamic winery to exclude interference due to microbial starters. Three winemaking protocols, with different pre-fermentative management of grapes, were followed by plate count and next generation sequencing on 16S for bacteria and internal transcribed spacer sequencing (ITS) for yeast. Chemical and sensory characterization of wine was performed. The grape processing influenced the evolution of microbiota (especially lactic and acetic acid bacteria) and the fermentation rate. The highest biodiversity was observed in the experiment carried out with whole grapes and carbonic maceration, with the presence of bacterial groups not usually found in winemaking (Bacteroidales, Clostridiales, Oscillospira). The different microbiotas influenced the organic acid profile of wines, the content of biogenic ammines and the perception of organoleptic descriptors linked to the vine cultivar (Syrah). CONCLUSIONS: Carbonic maceration impacts on the evolution of the microbiota and the wine features. The absence of addition of starters and sulphur dioxide would seem to be correlated with the high microbial biodiversity. SIGNIFICANCE AND IMPACT OF THE STUDY: Carbonic maceration is a traditional winemaking practice, today there are difficulties in its managing because the anaerobiosis stimulates spoilage micro-organisms. The work elucidates the reasons of these difficulties and identified some microbial groups rarely associated with winemaking. The ratio of ethanol accumulation along with physical management of grapes and the supply of oxygen during the early stages of winemaking are powerful instruments of oenological variability, able to offer new possibilities to winemakers in order to defining the quality of red wines.


Assuntos
Manipulação de Alimentos/métodos , Microbiota , Vitis/microbiologia , Vinho/microbiologia , Ácidos/análise , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Etanol/análise , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Oxigênio/metabolismo , Vinho/análise
10.
J Dairy Sci ; 103(1): 220-227, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31704015

RESUMO

This study was conducted to analyze the effect of milk types on the attributes of the glutinous rice wine-fermented yogurt-like product named Kouwan Lao (KWL). Four types of raw milks were used in this study, including high temperature, long time (HTLT: H milk), HTLT milk supplemented with 3% skim milk powder (S milk), pasteurized milk (P milk), and ultra-high temperature milk (U milk). Microbiological compositions of the fermented glutinous rice and KWL at different stages were analyzed using PCR-denaturing gradient gel electrophoresis and gene sequencing based on 16S rRNA and 26S rRNA. The physicochemical properties of KWL samples were determined, and textural properties of those were analyzed using a texture analyzer (Jiawei Innovation and Technology Co. Ltd., Zhejiang Province, China). The microstructure of KWL samples was observed using scanning electron microscopy. The results showed that the milk types had significant influences on the bacterial composition of KWL. In the curdling process, the predominant bacteria of H, S, P, and U KWL samples were Lactobacillus brevis, Janthinobacterium sp., Lactobacillus casei, and Streptococcus agalactiae, respectively. In the ripening process, the main strains in H KWL were Enterococcus faecium and Pediococcus pentosaceus. Lactobacillus casei and Lactobacillus paracasei were the dominant bacteria of U KWL. Lactobacillus casei was the main strain of P KWL, and no bacteria were detected in S KWL. Saccharomyces cerevisiae was the dominant fungus of KWL, and no significant effect of milk types on fungal composition of KWL was found. The results of physicochemical properties showed that significant differences in protein contents were found in the KWL samples, and P KWL had the highest protein content. The fat content of U KWL was significantly higher than that of samples from the other 3 groups. The U KWL and P KWL showed lower moisture than that of the other 2 KWL samples. In addition, no significant difference in pH value was found in all samples. The results of texture analysis and microstructure showed that compared with other 3 types of KWL samples, the related mass parameters of U KWL were more advantageous and improved significantly with the increase of the heat treatment temperature of raw milk and the addition of skim milk powder. Our findings revealed the effects of milk types on microbial composition, physicochemical properties, textural properties, and microstructure of KWL, and provided a basic theory for the optimization and industrial production of KWL.


Assuntos
Fenômenos Fisiológicos Bacterianos , Fungos/fisiologia , Leite/química , Iogurte/microbiologia , Animais , Bactérias/classificação , Eletroforese em Gel de Gradiente Desnaturante , Fermentação , Fungos/classificação , Oryza/química , Reação em Cadeia da Polimerase , Vinho/microbiologia
11.
Gut ; 69(1): 92-102, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31003979

RESUMO

OBJECTIVE: Patients with primary sclerosing cholangitis (PSC) were previously shown to display a bacterial gut dysbiosis but fungal microbiota has never been examined in these patients. The aim of this study was to assess the fungal gut microbiota in patients with PSC. DESIGN: We analysed the faecal microbiota of patients with PSC and concomitant IBD (n=27), patients with PSC and no IBD (n=22), patients with IBD and no PSC (n=33) and healthy subjects (n=30). Bacterial and fungal composition of the faecal microbiota was determined using 16S and ITS2 sequencing, respectively. RESULTS: We found that patients with PSC harboured bacterial dysbiosis characterised by a decreased biodiversity, an altered composition and a decreased correlation network density. These alterations of the microbiota were associated with PSC, independently of IBD status. For the first time, we showed that patients with PSC displayed a fungal gut dysbiosis, characterised by a relative increase in biodiversity and an altered composition. Notably, we observed an increased proportion of Exophiala and a decreased proportion of Saccharomyces cerevisiae. Compared with patients with IBD and healthy subjects, the gut microbiota of patients with PSC exhibited a strong disruption in bacteria-fungi correlation network, suggesting an alteration in the interkingdom crosstalk. CONCLUSION: This study demonstrates that bacteria and fungi contribute to gut dysbiosis in PSC.


Assuntos
Colangite Esclerosante/microbiologia , Disbiose/microbiologia , Fungos/isolamento & purificação , Microbioma Gastrointestinal , Adulto , Idoso , Bactérias/classificação , Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana/métodos , Biodiversidade , Feminino , Fungos/classificação , Humanos , Doenças Inflamatórias Intestinais/microbiologia , Masculino , Pessoa de Meia-Idade , Técnicas de Tipagem Micológica/métodos , Adulto Jovem
12.
Ultrason Sonochem ; 60: 104604, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31539730

RESUMO

The optimum formulation and ultrasonic condition for fabrication of cinnamon essential oil (CEO) nanoemulsion were determined using Response Surface Methodology (RSM). The CEO nanoemulsions were formed using an ultrasonic bath (43 kHz at power output of 210 W) and an ultrasonic probe (24 kHz at power of 400 W). Probe ultrasonication outperformed bath ultrasonication since it produced nanoemulsions with smaller droplet size, narrower size distribution as measured using polydispersity index (PDI), and higher viscosity. The influences of sonication time of 180.23-351.77 s, temperature of 4.82-45.18 °C, and Tween® 80 concentration of 1-3% w/w on the droplet size, PDI, and viscosity were investigated using RSM based on Box-Behnken design (BBD). The RSM revealed that the sonication time of 266 s, temperature of 4.82 °C, and Tween® 80 of 3% w/w produced the optimum CEO nanoemulsion with droplet size of 65.98 nm, PDI of 0.15, and viscosity of 1.67 mPa.s. Moreover, the optimum nanoemulsion had good stability in terms of droplet size and PDI when storing at 4, 30, and 45 °C for 90 days. The antifungal activity of the optimum CEO nanoemulsion was then investigated against Aspergillus niger, Rhizopus arrhizus, Penicillium sp., and Colletotrichum gloeosporioides in comparison to CEO coarse emulsion. The results showed that the CEO nanoemulsion had better antifungal activity than coarse emulsion of CEO.


Assuntos
Antifúngicos/farmacologia , Cinnamomum zeylanicum/química , Emulsões , Nanotecnologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Temperatura Baixa , Fungos/classificação , Fungos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Sonicação/métodos
13.
Phytochemistry ; 169: 112160, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31600654

RESUMO

Filamentous fungi is a huge phylum of lower eukaryotes with diverse activities towards various substrates, however, their biocatalytic potential towards steroids remains greatly underestimated. In this study, more than forty Ascomycota and Zygomycota fungal strains of 23 different genera were screened for the ability to catalyze structural modifications of 3-oxo-androstane steroids, - androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). Previously unexplored for these purposes strains of Absidia, Acremonium, Beauveria, Cunninghamella, Doratomyces, Drechslera, Fusarium, Gibberella genera were revealed capable of producing in a good yield valuable 7α-, 7ß-, 11α- and 14α-hydroxylated derivatives, as well as 17ß-reduced and 1(2)-dehydrogenated androstanes. The bioconversion routes of AD and ADD were proposed based on the key intermediates identification and time courses of the bioprocesses. Six ascomycete strains were discovered to provide effective 7ß-hydroxylation of ADD which has not been so far reported. The structures of major products and intermediates were confirmed by HPLC, mass-spectrometry (MS), 1H and 13C NMR analyses. The results contribute to the knowledge on the functional diversity of steroid-transforming filamentous fungi. Previously unexplored fungal biocatalysts capable of effective performing structural modification of AD and ADD can be applied for industrial bioprocesses of new generation.


Assuntos
Androstadienos/metabolismo , Androstenodiona/metabolismo , Fungos/metabolismo , Androstadienos/química , Androstadienos/isolamento & purificação , Androstenodiona/química , Androstenodiona/isolamento & purificação , Biotransformação , Fungos/química , Fungos/classificação , Conformação Molecular
14.
Lett Appl Microbiol ; 70(1): 55-62, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31660628

RESUMO

This study investigated potential contamination sources in a commercial, closed hydroponic system. Water, substrate and lettuce (Lactuca sativa) samples were evaluated for microbiological indicator populations, including aerobic plate count (APC), coliform bacteria (CB) and yeast and mould (YM). Listeria spp. detection via cultural enrichment and agglutination was negative for all samples. Peat moss substrate (postharvest) had the highest counts for APC (6·8 log CFU per g), CB (4·5 log MPN per g) and YM (5·1 and 4·8 log CFU per g respectively). Roots embedded in plugs demonstrated counts for all populations nearly as high as the substrate. Among water samples, a seedling water reservoir housing germinated plants yielded the highest count for APC (5·1 log CFU per g) and CB (2·4 log MPN per g) likely due to the large numbers of plugs and their close proximity in the reservoir. Harvested lettuce leaves demonstrated higher APC (4·1 log CFU per g) than preharvest leaves (1·7 log CFU per g) due to the transfer of microbes from the root ball. These data suggest that substrates are a significant potential source of contamination in hydroponic systems and likely facilitate microbial transfer to harvested leaves. There is, therefore, the need to further investigate mitigation of potential contamination events. SIGNIFICANCE AND IMPACT OF THE STUDY: Hydroponic production is known to provide safe, clean produce. This study, however, suggests that the hydroponic substrate (peat moss plug) is a possible source of contamination in the hydroponic system. This finding is important as most harvested hydroponic lettuces are packaged and sold with substrate and root ball intact. This implies a high probability of microbial transfer from the root ball to edible harvested lettuce leaves.


Assuntos
Bactérias/isolamento & purificação , Contaminação de Alimentos/análise , Fungos/isolamento & purificação , Alface/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Meios de Cultura/química , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Hidroponia/instrumentação , Alface/crescimento & desenvolvimento , Folhas de Planta/microbiologia
15.
J Appl Microbiol ; 128(1): 138-150, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31495045

RESUMO

AIMS: In order to understand the response of soil microbial communities to the long-term of decomposed straw return, the modifications of soil microbial community structure and composition induced by more than 10 years of fresh and decomposed straw return was investigated and the key environmental factors were analysed. METHODS AND RESULTS: Phospholipid fatty acid analysis and high-through sequencing technique were applied to analyse the structure and composition of the soil microbial communities. Compared with fresh straw, returning decomposed straw increased the relative abundance of bacteria and fungi by 1·9 and 7·7% at a rate of ~3750 kg ha-1 , and increased by 23·1 and 5·7%, at a rate of ~7500 kg ha-1 respectively. The relative abundance of the bacteria related to soil nitrification increased, but the ones related to soil denitrification decreased with decomposed straw return, which led to higher total nitrogen contents in soils. Moreover, returning decomposed straw reduced pathogenic fungal populations (genus of Alternara), which had significantly positive correlation with soil electric conductivity. It indicated that the long-term of decomposed straw return might have lower risk of soil-borne disease mainly for the reasonable soil salinity. CONCLUSIONS: Long-term of decomposed straw return could provide suitable nutrient and salinity for healthier development of soil microbial community, both in abundance and structure, compared with fresh straw return. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the study helps to better understand how the microbial community modifications induced by decomposed straw return benefit on soil health. The obtained key factors impacting soil microbial community variations is meaningful in soil health management under conditions of straw return.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais , Microbiota , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Condutividade Elétrica , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Nitrificação , Nitrogênio/análise , Solo/química
16.
Food Microbiol ; 86: 103347, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703852

RESUMO

Gutian Hong Qu glutinous rice wine (GHQW) is a representative alcoholic beverage in China. During its traditional brewing process, multiple strains are involved. However, the roles of these microorganisms, particularly their contributions to aroma formation, are poorly understood. Therefore, in this study, the dynamics of volatile components and microbial succession during the traditional fermentation process of GHQW were monitored, by using HS-SPME-GC/MS and high throughput 16 S rRNA and ITS sequencing techniques. Following a 32-day semi-open solid-state fermentation, massive changes in volatile profile and microbial communities were observed. Based on these, the potential correlations between volatile components and microorganisms during the fermentation were explored by using Pearson correlation analysis. It was revealed that 3 bacterial taxa, including Lactococcus lactis, Burkholderia gladioli and Cronobacter helveticus, and 5 fungal taxa, including Wickerhamomyces anomalus, Saccharomyces cerevisiae, Aspergillus vitricola, Aspergillus penicillioides and Monascus purpureus, showed strong connections with various volatile components. Thus these bacteria and fungi might play crucial roles in volatile components biosynthesis, and thus were preliminary considered as core functional microorganisms for GHQW brewing. The detailed information on the dynamic changes of volatile components and microbial communities throughout GHQW brewing can further expand our understanding of the formation mechanisms of GHQW aroma.


Assuntos
Bactérias/metabolismo , Fungos/metabolismo , Oryza/microbiologia , Compostos Orgânicos Voláteis/metabolismo , Vinho/análise , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , China , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Microbiota , Oryza/química , Compostos Orgânicos Voláteis/química , Vinho/microbiologia
17.
Food Microbiol ; 86: 103340, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703864

RESUMO

Red sufu is a traditional food produced by the fermentation of soybean. In this study, sufu samples were periodically collected during the whole fermentation to investigate the dynamic changes of fungal and bacterial communities using high-throughput sequencing technology. The overall process can be divided into pre- and post-fermentation. During post-fermentation, the pH value showed a gradual decrease over time while the amino nitrogen content increased. Trichosporon, Actinomucor and Cryptococcus were the main genera in pre-fermentation while Monascus and Aspergillus were dominant in post-fermentation. This huge shift in fungal composition was caused by process procedure of pouring dressing mixture. However, the bacterial composition was not greatly changed after pouring dressing mixture, the Acinetobacter and Enterobacter were the predominant genera throughout the whole process. Furthermore, Bacillus species were first detected after adding dressing mixture, but declined abruptly to a very low level (0.07%) by the end of the fermentation. Our work demonstrates the dynamic changes of physicochemical properties and microbial composition in every fermentation stage, the knowledge of which could potentially serve as a foundation for improving the safety and quality of sufu in the future.


Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbiota , Alimentos de Soja/microbiologia , Soja/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Alimentos de Soja/análise , Soja/metabolismo
18.
Food Microbiol ; 86: 103329, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703874

RESUMO

Four sets of doenjang (traditional Korean fermented soybean paste) with 9%, 12%, 15%, and 18% solar salt concentrations were prepared and their pH, microbial abundances and communities, metabolites, and volatile compounds were analyzed periodically during the entire fermentation. The speeds of decrease in pH and increase in microbial abundances, representing microbial activity, were higher during early fermentation in lower (9% and 12%) salt doenjang. Microbial abundances in 15% and 18% salt doenjang were significantly lower than in the 9% and 12% salt doenjang, indicating low microbial activity. Community analysis revealed that Bacillus, Staphylococcus, and Clostridium and Aspergillus, Scopulariopsis, Fusarium, Mucor, and Penicillium, which might be derived from doenjang-meju used for preparing doenjang, were identified as major bacterial and fungal genera, respectively, in all doenjang samples. Weissella, Tetragenococcus, Oceanobacillus, and Debaryomyces, not dominant in doenjang-meju, were also identified as major groups in low salt doenjang. Metabolite analysis showed that amino acid profiles were relatively similar independent of salt concentrations and microbial growth, indicating important roles of indigenous proteases present in doenjang-meju, not microbial activity during doenjang fermentation, in amino acid production. The metabolism of free sugars to organic acids and biogenic amine production were greater in lower salt doenjang, which might be associated with the growth of microbes, particularly lactic acid bacteria. A higher level of and more diverse volatile compounds were identified in lower salt doenjang, indicating close association with microbial growth. This study provides a deeper understanding of doenjang fermentation and insight into the development of low salt doenjang.


Assuntos
/microbiologia , Cloreto de Sódio/análise , Soja/microbiologia , Ácidos/análise , Ácidos/metabolismo , Aminoácidos/análise , Aminoácidos/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Aminas Biogênicas/análise , Aminas Biogênicas/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Cloreto de Sódio/metabolismo , Alimentos de Soja/análise , Alimentos de Soja/microbiologia
19.
J Sci Food Agric ; 100(1): 362-370, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31588997

RESUMO

BACKGROUND: Long-term drastic anthropic inputs in conventional monoculture systems cause negative plant-soil feedback that will largely affect sustainable cucumber cultivation. The inclusion of multicropping in intensive cropping systems could reduce the detrimental effects of continuous cropping obstacles. The present study investigated the dynamics of soil microbial communities, soil enzyme activities and cucumber yield under plastic tunnel cultivation for three successive growing seasons (2013, 2014 and 2015). RESULT: In the amended crop rotation system, soil pH decreased with increasing number of cropped garlic bulbs. The soil electrical conductivity significantly changed during the entire growth period and increased with increasing number of incorporated garlic bulbs. The level of soil organic matter content increased in the last year (2015). Soil catalase activity was generally induced by the treatments of 10, 15, 20 and 25 garlic bulbs, and soil invertase activity was also enhanced by all the treatments in the last year. Similarly, fungal species richness dramatically increased under these crop rotation systems. In this study, we found the highest cucumber yield under the cropping treatment of 20 garlic bulbs. CONCLUSION: The results indicate that the green garlic/cucumber cropping system is a sustainable and efficient cropping system for cucumber production and can improve the soil environment to a certain extent. © 2019 Society of Chemical Industry.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Alho/crescimento & desenvolvimento , Solo/química , China , Produção Agrícola , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Concentração de Íons de Hidrogênio , Estações do Ano , Microbiologia do Solo
20.
Ann Agric Environ Med ; 26(4): 555-565, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31885228

RESUMO

OBJECTIVE: The aim of this study was to assess microbial contamination of the air and surfaces at workplaces in commercial (CD) and traditional (TD) dairies. MATERIAL AND METHODS: Bioaerosol (impactor) and surface (swab) samples were collected in CD and in TD. Bacterial and fungal concentrations in the air and on surfaces were calculated and all isolated microorganisms taxonomically identified, based on their morphological, biochemical and molecular features. RESULTS: Average concentrations of bacterial aerosol ranged between 70-860 CFU/m3 and 265-14639 CFU/m3, while for fungal aerosol were between 50-290 CFU/m3 and 55-480 CFU/m3 in CD and TD, respectively. Average bacterial concentrations on surfaces ranged between 1.0-49.7 CFU/cm2 and 0.2-60.4 CFU/cm2, whereas average fungal surface contamination ranged between 0-2.7 CFU/cm2 and 0-4.6 CFU/cm2 in CD and TD, respectively. Qualitative analysis revealed mainly the presence of saprophytic microorganisms; however, several pathogenic strains (Staphylococcus aureus, Streptococcus intermedius, Clostridium perfringens, Actinomyces spp., Streptomyces spp., Candida albicans) were also isolated from both the air and surface samples in the studied dairies. CONCLUSIONS: The air and surfaces in TD were more polluted than those in CD; however, in both types of dairies, the levels of microbial contaminants did not exceed respective threshold limit values. Nevertheless, the presence of pathogenic microorganisms may increase health risk for dairy workers and influence the quality of products. Hence, proper hygienic measures should be introduced and performed to guarantee high microbial quality of both production processes and milk products.


Assuntos
Microbiologia do Ar , Bactérias/crescimento & desenvolvimento , Indústria de Laticínios/instrumentação , Fungos/crescimento & desenvolvimento , Exposição Ocupacional/análise , Aerossóis/química , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Indústria de Laticínios/economia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Humanos , Exposição por Inalação/efeitos adversos , Exposição por Inalação/análise , Exposição Ocupacional/efeitos adversos
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