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1.
Virus Res ; 307: 198580, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34688784

RESUMO

A novel phage vB_VpP_DE17, which infects Vibrio parahaemolyticus, was isolated from the sewer of the Huangsha aquatic market in Guangzhou. Transmission electron microscopy indicated that DE17 had an icosahedral head (47 ± 2 nm diameter) and a short, non-contractile tail (17 ± 2 nm). The genome of DE17 was a double-stranded linear DNA with a length of 43,397 bp and GC content of 49.23%. In total, 49 putative open reading frames (ORFs) were predicted and could be divided into six modules: DNA metabolism, lysis, packaging, structure, additional function, and hypothetical proteins. Taxonomic analysis revealed that the phage belonging to the genus of Maculvirus, Autographivirinae subfamily, Podoviridae family. DE17 had a short latent period of 5 min with burst size of 80 pfu/cell. Its optimum temperature and pH ranges were 4 °C-50 °C and 5-10, respectively; it was completely inactivated after 20 min of ultraviolet irradiation. No transfer RNA (tRNA), virulence associated, or antibiotic resistance genes were identified. Bacterial challenge test revealed that DE17 had a certain inhibitory effect on V. parahaemolyticus within 6 h. Characterization, genomic analysis and in vitro antibacterial assays of DE17 will further enhance our understanding of phage biology and diversity.

2.
Molecules ; 26(21)2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34770899

RESUMO

The extracellular secreted protein of Bifidobacterium longum (B. longum) plays an important role in maintaining the homeostasis of the human intestinal microenvironment. However, the mechanism(s) of interaction remain unclear. Lysozyme is a kind of antibacterial peptide. In this study, the amino acid sequence of a lysozyme-like protein of B. longum based on whole-genome data of an isolate from human gut feces was found. We further predicted functional domains from the amino acid sequence, purified the protein, and verified its bioactivity. The growth of some bacteria were significantly delayed by the 020402_LYZ M1 protein. In addition, the gut microbiota was analyzed via high-throughput sequencing of 16S rRNA genes and an in vitro fermentation model, and the fluctuations in the gut microbiota under the treatment of 020402_LYZ M1 protein were characterized. The 020402_LYZ M1 protein affected the composition of human gut microbiota significantly, implying that the protein is able to communicate with intestinal microbes as a regulatory factor.

3.
Ying Yong Sheng Tai Xue Bao ; 32(10): 3548-3556, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34676716

RESUMO

Using the principles and methods of dendrochronology, we measured tree-ring width of four dominant coniferous species, i.e., Larix potaninii var. macrocarpa, Picea brachytyla, Pinus densata, and Abies georgei, in the Potatso National Park, and established the tree-ring width resi-dual chronologies. We analyzed the correlation of tree-ring width residual chronologies with daily and monthly climate data from the Shangrila meteorological station to analyze the response of radial growth to climate factors. The results showed that L. potaninii var. macrocarpa had the highest annual growth rate, and A. georgei had the lowest. Radial growth showed species-specific responses to climate changes, with the highest sensitivity of L. potaninii var. macrocarpa and the lowest sensitivity of P. brachytyla. Ring-width chronology of A. georgei correlated positively with mean temperature during previous winter (November and December) and current summer (July). Ring-width chronology of L. potaninii var. macrocarpa correlated positively with temperature during the early-growing season (June), but negatively with precipitation and relative humidity. Ring-width chronology of P. densata correlated positively with precipitation and humidity but negatively with maximum temperature during the early-growing season (May), indicating that its radial growth was primarily influenced by water availability during the early-growing season.


Assuntos
Mudança Climática , Traqueófitas , China , Parques Recreativos , Árvores
4.
Virus Res ; 306: 198603, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34662679

RESUMO

Noroviruses are causative agents of acute nonbacterial gastroenteritis epidemics worldwide. There are various genotypes, among which the non-epidemic genotype GII.8 can cause norovirus outbreaks. We previously demonstrated that the immunogenicity of GII.8 differed from that of epidemic variants. This study aimed to comprehensively compare the receptor profile and immunogenicity of the GII.8 variant with those of the epidemic variants. Using the baculovirus-insect cell expression system, we observed that recombinant capsid protein VP1 of the norovirus GII.8 GZ2017-L601 strain formed virus-like particles (VLPs) with a diameter of approximately 30 nm, as evidenced by transmission electron microscopy analysis. The GII.8 VLPs showed weak or moderate binding with all secretor histo-blood group antigens (HBGAs), but not with non-secretors, as evidenced by the HBGA-VLP binding test. The GII.8 VLP antiserum obtained from immunized BALB/c mice was tested for cross-reactivity with other norovirus genotypes (n = 28). The results showed that this antiserum demonstrated moderate cross-reactivity with GI.1, GII.3, and GII.15; however, no cross-reactivity with the epidemic variants of GII.2, GII.4, and GII.17 was observed. Additionally, the blocking-antibody activity of GII.8 antisera against GII.4 VLP-HBGAs and GII.17 VLP-HBGAs interactions and the cross-blocking of GII.8 VLP-HBGAs interactions by GI.1 and GII.4 antisera were evaluated using the HBGAs-VLP blocking test. However, no cross-blocking effect was observed. In summary, the characterization of norovirus GII.8 VLPs and derived antisera revealed that the GII.8 immunogenicity differed from that of epidemic variants.

5.
Front Microbiol ; 12: 665243, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34526973

RESUMO

The process of soybean fermentation has been practiced for more than 3,000 years. Although Dajiang and Sufu are two popular fermented soybean products consumed in North China, limited information is available regarding their microbial composition. Hence, the current study sought to investigate, and compare, the physicochemical indicators and microbial communities of traditional Dajiang and Sufu. Results showed that the titratable acidity (TA), and salinity, as well as the lactic acid, and malic acid contents were significantly higher in Sufu samples compared to Dajiang. Furthermore, Sufu samples contain abundant sucrose and fructose, while the acetic acid content was lower in Sufu compared to Dajiang samples. Moreover, the predominant bacterial phyla in Dajiang and Sufu samples were Firmicutes and Proteobacteria, while the major genera comprise Bacillus, Lactobacillus, Tetragenococcus, and Weissella. Moreover, Dajiang samples also contained abundant Pseudomonas, and Brevundimonas spp., while Halomonas, Staphylococcus, Lysinibacillus, Enterobacter, Streptococcus, Acinetobacter, and Halanaerobium spp. were abundant in Sufu samples. At the species level, Bacillus velezensis, Tetragenococcus halophilus, Lactobacillus rennini, Weissella cibaria, Weissella viridescens, Pseudomonas brenneri, and Lactobacillus acidipiscis represented the major species in Dajiang, while Halomonas sp., Staphylococcus equorum, and Halanaerobium praevalens were the predominant species in Sufu. Acetic acid and sucrose were found to be the primary major physicochemical factor influencing the bacterial communities in Dajiang and Sufu, respectively. Furthermore, Bacillus subtilis is strongly correlated with lactic acid levels, L. acidipiscis is positively correlated with acetic acid levels, while Staphylococcus sciuri and S. equorum are strongly, and positively, correlated with malic acid. Following analysis of carbohydrate and amino acid metabolism in all samples, cysteine and methionine metabolism, as well as fatty acid biosynthesis-related genes are upregulated in Dajiang compared to Sufu samples. However, such as the Staphylococcus, W. viridescens, and P. brenneri, as potentially foodborne pathogens, existed in Dajang and Sufu samples. Cumulatively, these results suggested that Dajiang and Sufu have unique bacterial communities that influence their specific characteristics. Hence, the current study provides insights into the microbial community composition in Dajiang and Sufu samples, which may facilitate the isolation of functional bacterial species suitable for Dajiang and Sufu production, thus improving their production efficiency.

6.
Front Microbiol ; 12: 670488, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539594

RESUMO

Foodbone norovirus (NoV) is the leading cause of acute gastroenteritis worldwide. Candidate vaccines are being developed, however, no licensed vaccines are currently available for managing NoV infections. Screening for stimulated antibodies with broad-spectrum binding activities can be performed for the development of NoV polyvalent vaccines. In this study, we aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA) for testing the broad spectrum of anti-NoV antibodies. Capsid P proteins from 28 representative NoV strains (GI.1-GI.9 and GII.1-GII.22 except GII.11, GII.18, and GII.19) were selected, prepared, and used as coating antigens on one microplate. Combined with incubation and the horseradish peroxidase chromogenic reaction, the entire process for testing the spectrum of unknown antibodies required 2 h for completion. The intra-assay and inter-assay coefficients of variation were less than 10%. The new method was successfully performed with monoclonal antibodies and polyclonal antibodies induced by multiple antigens. In conclusion, the indirect ELISA assay developed in this study had a good performance of reliability, convenience, and high-throughput screening for broad-spectrum antibodies.

7.
Int J Food Microbiol ; 355: 109349, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34371389

RESUMO

Antibiotic-resistant bacteria in food pose an important threat to public health. Multidrug-resistant strains in ready-to-eat (RTE) foods can be transferred to humans through diet, which increases their health risk. This study systematically investigated antibiotic resistance and antibiotic resistance genes in E. coli isolated from retail RTE foods and characterized plasmid-mediated colistin-resistant E. coli strains. A total of 1118 RTE food samples were collected from markets in 39 cities in China, and 126 E. coli strains, >95% of which were multidrug-resistant, were isolated. The isolates showed a high prevalence of resistance to tetracycline (95.24%), ampicillin (82.54%), trimethoprim-sulfamethoxazole (77.78%), nalidixic acid (74.60%), cephalothin (72.22%), chloramphenicol (66.67%), and streptomycin (53.97%). Twenty-two extended-spectrum ß-lactamase (ESBL)-producing E. coli and four colistin-resistant E. coli were identified. The resistance genes TEM, CTX-M, tetA, sul2, strA/strB, aadA, and qnrS were the most frequently detected. CTX-M-55 and CTX-M-14 were the predominant CTX-M types. All the four colistin-resistant E. coli isolates were positive for mcr-1. The mcr-1 gene can be transferred to E. coli C600 through conjugation and transformation. Whole-genome sequencing revealed that the mcr-1 genes were found in IncX4 and IncHI2 plasmids. To the best of our knowledge, this is the first report of IncHI2/IncX4 plasmid-bearing mcr-1-positive E. coli strains in RTE foods sold in markets, and the first report of the isolation of the international epidemic E. coli clone ST101 and mcr-1-carrying ESBL-producing E. coli from RTE foods. These results provide valuable information for assessing antibiotic-resistant E. coli infections and controlling antibiotic-resistant E. coli.


Assuntos
Farmacorresistência Bacteriana Múltipla , Infecções por Escherichia coli , Proteínas de Escherichia coli , Escherichia coli , Fast Foods , Microbiologia de Alimentos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Fast Foods/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Prevalência , beta-Lactamases/genética
8.
Sci Rep ; 11(1): 17113, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429442

RESUMO

The existence of toxic and carcinogenic pentavalent antimony in water is a great safety problem. In order to remove antimony(V) from water, the purpose of this study was to prepare a novel graphene nano iron zinc (rGO/NZV-FeZn) photocatalyst via hydrothermal method followed by ultrasonication. Herein, weakly magnetic nano-Fe-Zn materials (NZV-FeZn, GACSP/NZV-FeZn, and rGO/NZV-FeZn) capable of rapid and efficient Sb(V) adsorption from water were prepared and characterised. In particular, rGO/NZV-FeZn was shown to comprise franklinite, Fe0, and graphite. Adsorption data were fitted by a quasi-second-order kinetic equation and Langmuir model, revealing that among these materials, NZV-FeZn exhibited the best Sb removal performance (543.9 mgSb gNZV-FeZn-1, R2 = 0.951). In a practical decontamination test, Sb removal efficiency of 99.38% was obtained for a reaction column filled with 3.5 g of rGO/NZV-FeZn. Column regenerability was tested at an initial concentration of 0.8111 mgSb L-1, and the treated water obtained after five consecutive runs complied with the GB5749-2006 requirement for Sb. rGO/NZV-FeZn was suggested to remove Sb(V) through adsorption-photocatalytic reduction and flocculation sedimentation mechanisms and, in view of its high cost performance, stability, and upscalable synthesis, was concluded to hold great promise for source water and wastewater treatment.

9.
Front Microbiol ; 12: 708795, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34385993

RESUMO

Vibrio parahaemolyticus is a common foodborne pathogen that causes gastroenteritis worldwide. Determining its prevalence and genetic diversity will minimize the risk of infection and the associated economic burden. Multilocus sequence typing (MLST) is an important tool for molecular epidemiology and population genetic studies of bacteria. Here, we analyzed the genetic and evolutionary relationships of 162 V. parahaemolyticus strains isolated in the Guangdong Province, China, using MLST. In the study, 120 strains were isolated from food samples, and 42 strains were isolated from clinical samples. All strains were categorized into 100 sequence types (STs), of which 58 were novel (48 from the food isolates and 10 from the clinical isolates). ST415 was the most prevalent ST among the food isolates, while ST3 was the most prevalent ST among the clinical isolates. Further, 12 clonal complexes, 14 doublets, and 73 singletons were identified in all ST clusters, indicating high genetic diversity of the analyzed strains. At the concatenated sequence level, non-synonymous sites in both, food and clinical isolates, were associated with purifying selection. Of note, the dN/dS ration was greater than 1 for some housekeeping genes in all isolates. This is the first time that some loci under positive selection were identified. These observations confirm frequent recombination events in V. parahaemolyticus. Recombination was much more important than mutation for genetic heterogeneity of the food isolates, but the probabilities of recombination and mutations were almost equal for the clinical isolates. Based on the phylogenetic analysis, the clinical isolates were concentrated in the maximum-likelihood tree, while the food isolates were heterogeneously distributed. In conclusion, the food and clinical isolates of V. parahaemolyticus from the Guangdong Province are similar, but show different evolutionary trends. This may help prevent large-scale spread of highly virulent strains and provides a genetic basis for the discovery of microevolutionary relationships in V. parahaemolyticus populations.

10.
Mikrochim Acta ; 188(8): 286, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34345968

RESUMO

A facile and versatile competitive electrochemical aptasensor for tobramycin (TOB) detection is described using electrochemical-deposited AuNPs coordinated with PEI-functionalized Fe-based metal-organic framework (AuNPs/P-MOF) as signal-amplification platform and a DNA probe labeled with methylene blue (MB) at the 3'-end (MB-Probe) as a signal producer. First, F-Probe (short complementary DNA strands of both the aptamer and the MB-Probe label with a sulfhydryl group at the 5'-end) was immobilized on the AuNPs/P-MOF modified electrode as detection probes, which competed with TOB in binding to the aptamer. TOB-aptamer binding resulted in F-Probe remaining unhybridized on the electrode surface, so that a significant current response was generated by hybridizing with MB-Probe instead. The developed strategy showed favorable repeatability, with a relative standard deviation (RSD) of 4.3% computed over five independent assays, and high stability, with only 6.8% degradation after 15 days of storage. Under optimal conditions, the proposed aptamer strategy exhibited a linear detection range from 100 pM to 500 nM with a limit of detection (LOD) of 56 pM (S/N = 3). The electrochemical aptasensor demonstrated remarkable selectivity, and its feasibility for accurate and quantitative detection of TOB in milk samples was confirmed (RSD < 4.5%). Due to its simple design, easy operation, and high sensitivity and selectivity, the proposed method could expect to detect other antibiotics by replacing the aptamers. In summary, this study provides a simple and effective new strategy for electrochemical aptasening based on MOF-based sensing interface. Scheme illustration of label-free competitive electrochemical aptamer-based detection of tobramycin based on electrochemically deposited AuNPs coordinated with PEI-functionalized Fe-based metal-organic framework as signal-amplification platform.

11.
Antibiotics (Basel) ; 10(8)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34439056

RESUMO

Antibiotic resistance in bacteria has become a major global health problem. One of the main reservoirs of antibiotic resistance genes is the human gut microbiota. To characterise these genes, a metagenomic approach was used. In this study, a comprehensive antibiotic resistome catalog was established using fecal samples from 246 healthy individuals from world's longevity township in Jiaoling, China. In total, 606 antibiotic resistance genes were detected. Our results indicated that antibiotic resistance genes in the human gut microbiota accumulate and become more complex with age as older groups harbour the highest abundance of these genes. Tetracycline resistance gene type tetQ was the most abundant group of antibiotic resistance genes in gut microbiota, and the main carrier of antibiotic resistance genes was Bacteroides. Antibiotic efflux, inactivation, and target alteration were found to be the dominant antimicrobial resistance mechanisms. This research may help to establish a comprehensive antibiotic resistance catalog that includes extremely long-lived healthy people such as centenarians, and may provide potential recommendations for controlling the use of antibiotics.

12.
Pathogens ; 10(8)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34451450

RESUMO

Human norovirus (HuNoV), which is the major causative agent of acute gastroenteritis, has broad antigenic diversity; thus, the development of a broad-spectrum vaccine is challenging. To establish the relationship between viral genetic diversity and antigenic diversity, capsid P proteins and antisera of seven GI and 16 GII HuNoV genotypes were analyzed. Enzyme-linked immunosorbent assays showed that HuNoV antisera strongly reacted with the homologous capsid P proteins (with titers > 5 × 104). However, 17 (73.9%) antisera had weak or no cross-reactivity with heterologous genotypes. Interestingly, the GII.5 antiserum cross-reacted with seven (30.4%) capsid P proteins (including pandemic genotypes GII.4 and GII.17), indicating its potential use for HuNoV vaccine development. Moreover, GI.2 and GI.6 antigens reacted widely with heterologous antisera (n ≥ 5). Sequence alignment and phylogenetic analyses of the P proteins revealed conserved regions, which may be responsible for the immune crossover reactivity observed. These findings may be helpful in identifying broad-spectrum epitopes with clinical value for the development of a future vaccine.

13.
Front Microbiol ; 12: 673872, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34354679

RESUMO

Human norovirus is a common cause of acute gastroenteritis worldwide, and oysters have been found to be the main carriers for its spread. The lack of efficient pre-treatment methods has been a major bottleneck limiting the detection of viruses in oysters. In this study, we established a novel immunomagnetic enrichment method using polyamidoamine (PAMAM) dendrimer/SA-biotin-mediated cascade amplification for reverse transcriptase quantitative real-time polymerase chain reaction (RT-qPCR) detection. We compared the capture efficiency of traditional immunomagnetic enrichment, biotin-amplified immunomagnetic enrichment, and PAMAM dendrimer/SA-biotin-mediated cascade-amplification immunomagnetic enrichment. The optimal capture efficiency of the novel method was 44.26 ± 1.45%, which increased by 183.17% (P < 0.01) and 18.09% (P < 0.05) compared with the first two methods, respectively. Three methods were all applied in detecting norovirus in 44 retail oysters, the detection rate of the PAMAM dendrimer/SA-biotin-mediated method was 25.0%, which was higher than those of traditional IME (15.90%) and SA-biotin-amplified IME (18.80%) by 9.1 and 6.2%, respectively. In conclusion, the novel method can be applied for the rapid detection of norovirus in oysters, which can help reduce the cost and time of detection and improve detection rates.

14.
Bioorg Chem ; 116: 105274, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34455301

RESUMO

Traditional Chinese herbal compound prescription in Xuanfei Baidu Tang (XBT) has obvious effects in the treatment of COVID-19. However, its effective compounds and targets for the treatment of COVID-19 remain unclear. Computer-Aided Drug Design is used to virtually screen out the anti-inflammatory or anti-viral compounds in XBT, and predict the potential targets by Discovery Studio 2020. Then, we searched for COVID-19 targets using Genecards databases and Protein Data Bank (PDB) databases and compared them to identify targets that were common to both. Finally, the target we screened out is: TP53 (Tumor Protein P53). This article also shows that XBT in the treatment of COVID-19 works in a multi-link and overall synergistic manner. Our results will help to design the new drugs for COVID-19.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Antivirais/farmacologia , COVID-19/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , SARS-CoV-2/efeitos dos fármacos , Anti-Inflamatórios não Esteroides/química , Antivirais/química , Avaliação Pré-Clínica de Medicamentos , Medicamentos de Ervas Chinesas/química , Humanos , Medicina Tradicional Chinesa , Estrutura Molecular , SARS-CoV-2/metabolismo , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo
15.
Int J Food Microbiol ; 354: 109320, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34229231

RESUMO

Campylobacter spp., such as Campylobacter jejuni and Campylobacter coli, are important zoonotic Gram-negative pathogens that cause acute intestinal diseases in humans. The optrA gene, encoding an ATP-binding cassette F (ABC-F) protein that confers resistance to oxazolidinones and phenicols, has been found in C. coli in China. In this study, the optrA gene was first identified in C. jejuni collected from retail meat in China from 2013 to 2016. Nine strains, isolated from a pigeon meat sample, carry the optrA gene. The molecular characteristics of the optrA-positive strains were determined by whole genome sequencing. Pulsed-field gel electrophoresis, multilocus sequence typing, and single nucleotide polymorphism analyses demonstrated that the nine optrA-positive isolates were genetically homogeneous. Phylogenetic characteristics and sequence comparison revealed that optrA was located on a chromosome-borne multidrug resistance genomic island. The optrA gene along with the tet(O) gene formed two different translocatable units (TUs), thereby supporting the transmission of TU-associated resistance genes. The emergence and spread of such TUs and strains are of great concern in terms of food safety, and measures must be implemented to avoid their dissemination in other Gram-negative bacteria and food chains.


Assuntos
Campylobacter jejuni , Columbidae , Resistência a Múltiplos Medicamentos , Ilhas Genômicas , Carne , Animais , Antibacterianos/farmacologia , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/genética , Columbidae/microbiologia , Farmacorresistência Bacteriana/genética , Resistência a Múltiplos Medicamentos/genética , Ilhas Genômicas/genética , Humanos , Carne/microbiologia , Testes de Sensibilidade Microbiana , Filogenia
16.
Front Microbiol ; 12: 687511, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34326823

RESUMO

Phenol is a toxic organic molecule that is widely detected in the natural environment, even in drinking water sources. Biological methods were considered to be a good tool for phenol removal, especially microbial immobilized technology. However, research on the "seed" bacteria along with microbial community analysis in oligotrophic environment such as drinking water system has not been addressed. In this study, Acinetobacter sp. DW-1 with high phenol degradation ability had been isolated from a drinking water biofilter was used as seeded bacteria to treat phenol micro-polluted drinking water source. Meanwhile, the whole genome of strain DW-1 was sequenced using nanopore technology. The genomic analysis suggests that Acinetobacter sp. DW-1 could utilize phenol via the ß-ketoadipate pathway, including the catechol and protocatechuate branches. Subsequently, a bio-enhanced polyhedral hollow polypropylene sphere (BEPHPS) filter was constructed to investigate the stability of the seeded bacteria during the water treatment process. The denatured gradient gel electrophoresis (DGGE) profile and the quantification of phenol hydroxylase gene results indicate that when the BEPHPS filter was operated for 56 days, Acinetobacter sp. was still a persistent and competitive bacterium in the treatment group. In addition, 16S rRNA gene amplicon sequencing results indicate that Acinetobacter sp., as well as Pseudomonas sp., Nitrospira sp., Rubrivivax sp. were the predominant bacteria in the treatment group, which were different from that in the CK group. This study provides a better understanding of the mechanisms of phenol degradation by Acinetobacter sp. DW-1 at the gene level, and provides new insights into the stability of seeded bacteria and its effects on microbial ecology during drinking water treatment.

17.
Nutrients ; 13(6)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207558

RESUMO

Hypercholesterolemia can cause many diseases, but it can effectively regulated by Lactobacillus. This study aimed to evaluate the cholesterol-lowering mechanism of Enterococcus faecium strain 132 and Lactobacillusparacasei strain 201. These results showed that both the strains decreased serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), liver TC and TG and increased fecal TC, TG and total bile acid (TBA) levels. Additionally, both strains also reduced glutamic-pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST) and levels of tissue inflammation levels to improve the lipid profile, and they reduced fat accumulation partially by alleviating inflammatory responses. Furthermore, both strains regulated the expression of the CYP8B1, CYP7A1, SREBP-1, SCD1 and LDL-R gene to promote cholesterol metabolism and reduce TG accumulation. Interventions with both strains also altered the gut microbiota, and decreasing the abundance of Veillonellaceae, Erysipelotrichaceae and Prevotella. Furthermore, fecal acetic acid and propionic acid were increased by this intervention. Overall, the results suggested that E. faecium strain 132 and L. paracasei strain 201 can alleviate hypercholesterolemia in rats and might be applied as a new type of hypercholesterolemia agent in functional foods.


Assuntos
Anticolesterolemiantes/farmacologia , Colesterol/metabolismo , Enterococcus faecium , Hipercolesterolemia/microbiologia , Lactobacillus paracasei , Probióticos/farmacologia , Ácido Acético/análise , Animais , Colesterol 7-alfa-Hidroxilase/metabolismo , LDL-Colesterol/metabolismo , Modelos Animais de Doenças , Fezes/química , Fezes/microbiologia , Alimento Funcional/microbiologia , Microbioma Gastrointestinal/fisiologia , Humanos , Hipercolesterolemia/metabolismo , Fígado/metabolismo , Fígado/microbiologia , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Masculino , Propionatos/análise , Ratos , Estearoil-CoA Dessaturase/metabolismo , Esteroide 12-alfa-Hidroxilase/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Triglicerídeos/metabolismo
18.
J Food Biochem ; : e13879, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34309037

RESUMO

Neurodegenerative diseases are considered to be among the diseases most threatening to human beings. Increasing evidence shows that antioxidant hydrolysates/peptides with neuroprotective effects may relieve neurodegenerative diseases. However, related research in mushrooms, one of the richest sources of antioxidant hydrolysates/peptides, is in its infancy. Therefore, the in vitro neuroprotective effects of protein hydrolysates from Pleurotus geesteranus were researched in this study. Proteins were extracted from P. geesteranus and then hydrolyzed by simulated gastrointestinal digestion. The neuroprotective effects of the protein hydrolysates were evaluated by H2 O2 -injured PC12 cells. The hydrolysates showed a superior antioxidative ability and had a higher abundance of hydrophobic amino acids (e.g., leucine, alanine, and phenylalanine). Neither cytotoxicity nor the increase of ROS in PC12 cells was observed under treatment with the hydrolysates. However, pre-treatment with the hydrolysates in PC12 cells, which were then injured by H2 O2 , markedly attenuated ROS generation and enhanced the activities and mRNA expression of the endogenous antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)), leading to a 26.68% increase in cell viability. The hydrolysates exhibited strong neuroprotective activity in H2 O2 -injured PC12 cells, possibly by reducing ROS generation and enhancing the activity of the antioxidant enzymatic system. PRACTICAL APPLICATIONS: Antioxidant hydrolysates with neuroprotection were obtained from Pleurotus geesteranus proteins by simulating gastrointestinal digestion, which exhibited an excellent pre-protective effect in oxidatively damaged PC12 cells. Further study showed that hydrolysates pre-protection may exert antioxidant activities not only as an exogenous antioxidant to scavenge ROS but also as a gene regulator to modulate the endogenous antioxidant enzymes gene expression. These results indicated that the potential of antioxidant peptides, derived from P. geesteranus through gastrointestinal digestion, could serve as a source of bioactive molecules in the prevention, relief or even treatment of neurodegenerative disorders.

19.
Front Microbiol ; 12: 664810, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34234757

RESUMO

Salmonella is a widely distributed foodborne pathogen. The use of Salmonella phages as biocontrol agents has recently gained significant interest. Because the Salmonella genus has high diversity, efforts are necessary to identify lytic Salmonella phages focusing on different serovars. Here, five Salmonella phages were isolated from soil samples, and vB_SalP_TR2 was selected as a novel phage with high lytic potential against the host Salmonella serovar Albany, as well as other tested serovars, including Corvallis, Newport, Kottbus, and Istanbul. Morphological analyses demonstrated that phage vB_SalP_TR2 belongs to the Podoviridae family, with an icosahedral head (62 ± 0.5 nm in diameter and 60 ± 1 nm in length) and a short tail (35 ± 1 nm in length). The latent period and burst size of phage vB_SalP_TR2 was 15 min and 211 PFU/cell, respectively. It contained a linear dsDNA of 71,453 bp, and G + C content was 40.64%. Among 96 putative open reading frames detected, only 35 gene products were found in database searches, with no virulence or antibiotic resistance genes being identified. As a biological control agent, phage vB_SalP_TR2 exhibited a high temperature and pH tolerance. In vitro, it lysed most S. Albany after 24 h at 37°C with multiplicities of infection of 0.0001, 0.001, 0.01, 0.1, 1, 10, and 100. In food matrices (milk and chicken meat), treatment with phage vB_SalP_TR2 also reduced the number of S. Albany compared with that in controls. These findings highlighted phage vB_SalP_TR2 as a potential antibacterial agent for the control of Salmonella in food samples.

20.
Biosens Bioelectron ; 190: 113394, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118762

RESUMO

To achieve rapid and sensitive detection of aflatoxin B1 (AFB1), we developed a polydimethylsiloxane gravity-driven cyclic microfluidic chip using the two-signal mode strategy. The structural design of the chip, together with the two-wavelength quantum dot ratio fluorescence, effectively eliminates the influence of environmental factors, improves the signal stability, and ensures that the final detection result positively correlates with the target concentration. Moreover, the theoretical analysis performed for the established physical model of the three-dimensional reaction interface inside the chip confirmed the improved reaction rate of immune adsorption in the microfluidic strategy. Overall, the method exhibited a wide analytic range (0.2-500 ng mL-1), low detection limit (0.06 ng mL-1), high specificity, good precision (coefficient of variation < 5%), excellent reusability (20 times, 89.1%) and satisfactory practical sample analysis capacity. Furthermore, the reusability and designability of this chip provide a reliable scheme for field detection of AFB1, analysis of other small molecules, and establishment of high-throughput detection systems under different conditions.


Assuntos
Técnicas Biossensoriais , Pontos Quânticos , Aflatoxina B1/análise , Imunoensaio , Limite de Detecção , Microfluídica
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