RESUMEN
This study was conducted to reveal the prevalence, molecular characterization, and antibiotic susceptibility of Bacillus cereus isolated from dairy products including powdered infant formula, raw milk, pasteurized milk, ultra-high-temperature milk, and cheese. Five hundred samples collected from 5 provinces in China were analyzed in overall experiments. Multilocus sequence typing, distribution of toxin genes, and antibiotic susceptibility of the isolates were analyzed. Fifty-four B. cereus strains were detected; of these, 13 isolates (26%) were from raw milk, 12 isolates (12%) from pasteurized milk, 10 isolates (10%) from cheese, 12 isolates (8%) from ultra-high-temperature milk, and 7 isolates (7%) from powdered infant formula. These isolates were divided into 24 sequence types (ST); among them, ST24, ST26, ST82, ST142, ST377, ST857, and ST1046 were the main dominant ST. The results of detection of toxin genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK, entFM, bceT, hlyII, and cesB) showed that 94.4% isolates carried nheABC genes, whereas only 11.1% of the isolates contained the hblACD gene cluster. In addition, detection rates of cytK, bceT, entFM, hlyII, and cesB genes were 75.9, 77.8, 85.2, 53.7, and 11.1%, respectively. The antibiotic susceptibility test indicated that most of B. cereus isolates were resistant to ampicillin, penicillin, cefepime, cephalothin, and oxacillin, and were susceptible to gentamicin, chloramphenicol, imipenem, tetracycline, ciprofloxacin, trimethoprim-sulfamethoxazole, erythromycin, kanamycin, and cefotetan. Therefore, this study revealed the prevalence and characteristics of B. cereus isolated from dairy products in China, indicating the potential risk and contributing to the effective prevention and control of this pathogen.
Asunto(s)
Bacillus cereus/aislamiento & purificación , Bacillus cereus/fisiología , Productos Lácteos/microbiología , Animales , Antibacterianos/farmacología , Bacillus cereus/efectos de los fármacos , Bacillus cereus/genética , China , Contaminación de Alimentos , Microbiología de Alimentos , Leche/química , Leche/microbiología , PrevalenciaRESUMEN
Bacillus cereus not only has adverse effects on the nutrition and shelf life of dairy products but also seriously endanger people's health. This study was conducted to reveal the prevalence and genetic diversity of B. cereus strains isolated from raw milk and cattle farm environments. A total 56 of B. cereus strains were detected from 300 environmental samples (soil, water, fodder, air, milk pails, milking machines, cowsheds, bedding, excrement, cow surfaces, udders, overalls, soles, and staff hand samples) and 50 raw milk samples, and divided into 18 sequence types (STs) using multilocus sequence typing method. These STs included ST27, ST61, ST92, ST142, ST168, ST208, ST378, ST427, ST766, ST 857, ST1098, ST1140, ST1194, ST1236, ST1336, ST1339, ST1341, and ST1348, among them, ST857 (7/56, 12.5%) was the dominant ST, and were detected from air, cowsheds, bedding, excrement, and raw milk samples. Our findings could reveal the distribution and genetic diversity of B. cereus strains in raw milk and cattle farm environments, and provide a theoretical basis for controlling the potential harm of this pathogenic bacteria in dairy products.
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Bacillus cereus/genética , Bacillus cereus/aislamiento & purificación , Leche/microbiología , Microbiología del Aire , Crianza de Animales Domésticos/instrumentación , Animales , Bacillus cereus/clasificación , Bovinos/microbiología , Granjas , Femenino , Variación Genética , Tipificación de Secuencias Multilocus , Filogenia , Microbiología del Suelo , Microbiología del AguaRESUMEN
This study was conducted to analyze the antibacterial effect of olive oil polyphenol extract (OOPE) against vegetative cells of Bacillus cereus isolated from raw milk and reveal the possible antibacterial mechanism. The diameter of inhibition zone, minimum inhibitory concentration, minimum bactericidal concentration, and survival counts of bacterial cells in sterile normal saline and pasteurized milk were used to evaluate the antibacterial activity of OOPE against B. cereus vegetative cells. The changes in intracellular ATP concentration, cell membrane potential, content of bacterial protein, and cell morphology were analyzed to reveal possible mechanisms of action. Our results showed the diameter of inhibition zone, minimum inhibitory concentration, and minimum bactericidal concentration of OOPE against B. cereus vegetative cells were 18.44 ± 0.55 mm, 0.625 mg/mL, and 1.25 mg/mL, respectively. Bacillus cereus GF-1 vegetative cells were decreased to undetectable levels from about 8 log cfu/mL after treatments with 0.625 mg/mL of OOPE in normal saline at 30°C for 3 h and in pasteurized milk at 30°C for 10 h. The antibacterial mechanisms of OOPE against B. cereus GF-1 vegetative cells may be due to the reduction of intracellular ATP concentrations, cell membrane depolarization, decrease of bacterial protein content, and leakage from cytoplasm. These findings illustrated that OOPE could be used to prevent the growth of contaminating B. cereus cells in dairy products.
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Antibacterianos/farmacología , Bacillus cereus/efectos de los fármacos , Leche/microbiología , Aceite de Oliva/química , Extractos Vegetales/farmacología , Polifenoles/farmacología , Animales , Bacillus cereus/fisiología , Microbiología de Alimentos , Pruebas de Sensibilidad Microbiana , Polifenoles/aislamiento & purificaciónRESUMEN
The genus Homoneura comprises over 700 described species in eight known subgenera distributed worldwide and has the highest species richness of Lauxaniidae. Five subgenera and more than 200 species have currently been recorded from China. Despite its high diversity, the monophyly of Homoneura and its subgenera, and the phylogenetic relationships among its subgenera remain to be investigated. One maximum-parsimony tree was generated based on 105 morphological characters scored from 24 species, representing all five subgenera of Homoneura recorded from China. The results did not support the monophyly of the genus Homoneura and subgenus Homoneura. The subgenus Chaetohomoneura is a sister to subgenus Neohomoneura. The monophyly of the subgenera Euhomoneura and Neohomoneura is supported. Much of the current classification of the genus Homoneura needs a revision before taxonomy can reflect natural groupings.
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Four species of the genus Luzonomyza Malloch, 1929 from southwest China are described as new to science: Luzonomyzavittifacies Li & Yang, sp. nov., L.serrata Li & Yang, sp. nov., L.honghensis Li & Yang, sp. nov., and L.brevis Li & Yang, sp. nov. A key to Luzonomyza species is also presented.
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Pomegranate (Punica granatum Linn) is used in the prevention and treatment of metabolic syndrome in recent decades. Imbalances in lipid metabolism are profound features of metabolic disorders. In vivo and in vitro studies have shown that extracts of different pomegranate fractions (peels, flowers, juice, and seeds) regulate lipid metabolism in metabolic-disorder-associated diseases such as atherosclerosis, nonalcoholic fatty liver disease, and type 2 diabetes, helping to alleviate the development of diseases. Amelioration of oxidative stress and the inflammatory response is considered an important reason underlying the regulation of lipid metabolism by pomegranate extracts. Mitochondria, the major cellular site for lipid oxidation, are strongly associated with cellular oxidative and inflammatory status and are likely to be a target for pomegranate extract action. This review summarizes the main findings about the effects of different pomegranate fraction extracts on lipid metabolism in metabolic-disorder-associated diseases and analyses how pomegranate extracts achieve their effects. Furthermore, it also provides an important basis for the research and development of pomegranate-related nutrients or drugs.
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Metabolismo de los Lípidos/efectos de los fármacos , Enfermedades Metabólicas/metabolismo , Extractos Vegetales/farmacología , Granada (Fruta) , Aterosclerosis/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Granada (Fruta)/químicaRESUMEN
Macrophage cholesterol accumulation and foam cell formation are the hallmarks of early atherogenesis. Many plant polyphenols have been shown to inhibit macrophage foam cell formation and the development of atherosclerotic lesions. However, the effect of pomegranate peel polyphenols on foam cells remains unclear. In this study, the potential atheroprotective actions of pomegranate peel polyphenols on cholesterol accumulation and outflow in raw264.7 macrophages, and the mechanisms, were investigated. The results showed that the pomegranate peel polyphenols reduced ox-LDL internalization to diminish foam cell formation, as measured by oil-red O staining in raw264.7 macrophages, which may be due to decreasing the macrophage CD36 protein expression and not SR-A. In addition, pomegranate peel polyphenols promoted apoA-1-mediated macrophage cholesterol efflux by up-regulating ABCA1 and LXRα at the mRNA and protein levels, independently of ABCG1 and PPARγ.