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Powdery mildew fungi are obligate biotrophic pathogens that only invade plant epidermal cells. There are two epidermal surfaces in every plant leaf: the adaxial (upper) side and the abaxial (lower) side. While both leaf surfaces can be susceptible to adapted powdery mildew fungi in many plant species, there have been observations of leaf abaxial immunity in some plant species including Arabidopsis. The genetic basis of such leaf abaxial immunity remains unknown. In this study, we tested a series of Arabidopsis mutants defective in one or more known defense pathways with the adapted powdery mildew isolate Golovinomyces cichoracearum UCSC1. We found that leaf abaxial immunity was significantly compromised in mutants impaired for both the EDS1/PAD4- and PEN2/PEN3-dependent defenses. Consistently, expression of EDS1-yellow fluorescent protein and PEN2-green fluorescent protein fusions from their respective native promoters in the respective eds1-2 and pen2-1 mutant backgrounds was higher in the abaxial epidermal cells than in the adaxial epidermal cells. Altogether, our results indicate that leaf abaxial immunity against powdery mildew in Arabidopsis is at least partially due to enhanced EDS1/PAD4- and PEN2/PEN3-dependent defenses. Such transcriptionally pre-programmed defense mechanisms may underlie leaf abaxial immunity in other plant species such as hemp and may be exploited for engineering adaxial immunity against powdery mildew fungi in crop plants.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regiones Promotoras Genéticas , Hojas de la Planta/metabolismo , Mecanismos de Defensa , Enfermedades de las Plantas/microbiologíaRESUMEN
Neural network (i.e. deep learning, NN)-based data analysis techniques have been listed as a pivotal opportunity to protect the integrity and safety of the global food supply chain and forecast $11.2 billion in agriculture markets. As a general-purpose data analytic tool, NN has been applied in several areas of food science, such as food recognition, food supply chain security and omics analysis, and so on. Therefore, given the rapid emergence of NN applications in food safety, this review aims to provide a comprehensive overview of the NN application in food analysis for the first time, focusing on domain-specific applications in food analysis by introducing fundamental methodology, reviewing recent and notable progress, and discussing challenges and potential pitfalls. NN demonstrated that it has a bright future through effective collaboration between food specialist and the broader community in the food field, for example, superiority in food recognition, sensory evaluation, pattern recognition of spectroscopy and chromatography. However, major challenges impeded NN extension including void in the food scientist-friendly interface software package, incomprehensible model behavior, multi-source heterogeneous data, and so on. The breakthrough from other fields proved NN has the potential to offer a revolution in the immediate future.
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BACKGROUND: Powdery mildew (PM) is one of the most important and widespread plant diseases caused by biotrophic fungi. Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand such distinct modes of host-adaptation, we sequenced the genomes of four dicot PM biotypes belonging to Golovinomyces cichoracearum or Oidium neolycopersici. RESULTS: We compared genomes of the four dicot PM together with those of Blumeria graminis f.sp. hordei (both DH14 and RACE1 isolates), B. graminis f.sp. tritici, and Erysiphe necator infectious on barley, wheat and grapevine, respectively. We found that despite having a similar gene number (6620-6961), the PM genomes vary from 120 to 222 Mb in size. This high-level of genome size variation is indicative of highly differential transposon activities in the PM genomes. While the total number of genes in any given PM genome is only about half of that in the genomes of closely related ascomycete fungi, most (~ 93%) of the ascomycete core genes (ACGs) can be found in the PM genomes. Yet, 186 ACGs were found absent in at least two of the eight PM genomes, of which 35 are missing in some dicot PM biotypes, but present in the three monocot PM genomes, indicating remarkable, independent and perhaps ongoing gene loss in different PM lineages. Consistent with this, we found that only 4192 (3819 singleton) genes are shared by all the eight PM genomes, the remaining genes are lineage- or biotype-specific. Strikingly, whereas the three monocot PM genomes possess up to 661 genes encoding candidate secreted effector proteins (CSEPs) with families containing up to 38 members, all the five dicot PM fungi have only 116-175 genes encoding CSEPs with limited gene amplification. CONCLUSIONS: Compared to monocot (grass) PM fungi, dicot PM fungi have a much smaller effectorome. This is consistent with their contrasting modes of host-adaption: while the monocot PM fungi show a high-level of host specialization, which may reflect an advanced host-pathogen arms race, the dicot PM fungi tend to practice polyphagy, which might have lessened selective pressure for escalating an with a particular host.
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Ascomicetos/genética , Genoma Fúngico , Especificidad del Huésped/genética , Enfermedades de las Plantas/microbiología , Adaptación Fisiológica , Ascomicetos/clasificación , Ascomicetos/patogenicidad , Eliminación de Gen , Perfilación de la Expresión Génica , Genes Fúngicos , Tamaño del Genoma , Secuenciación de Nucleótidos de Alto Rendimiento , Micelio/genética , Micelio/metabolismo , Técnicas de Tipificación Micológica , Poaceae/microbiologíaRESUMEN
Addressing the critical need for swift and precise nutritional profiling in healthcare and in food industry, this study pioneers the integration of vision-language models (VLMs) with chemical analysis techniques. A cutting-edge VLM is unveiled, utilizing the expansive UMDFood-90k database, to significantly improve the speed and accuracy of nutrient estimation processes. Demonstrating a macro-AUCROC of 0.921 for lipid quantification, the model exhibits less than 10% variance compared to traditional chemical analyses for over 82% of the analyzed food items. This innovative approach not only accelerates nutritional screening by 36.9% when tested amongst students but also sets a new benchmark in the precision of nutritional data compilation. This research marks a substantial leap forward in food science, employing a blend of advanced computational models and chemical validation to offer a rapid, high-throughput solution for nutritional analysis.
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Maintaining food safety and quality is critical for public health and food security. Conventional food preservation methods, such as pasteurization and dehydration, often change the overall organoleptic quality of the food products. Herein, we demonstrate a method that affects only a thin surface layer of the food, using beef as a model. In this method, Joule heating is generated by applying high electric power to a carbon substrate in <1 s, which causes a transient increase of the substrate temperature to > ~2000 K. The beef surface in direct contact with the heating substrate is subjected to ultra-high temperature flash heating, leading to the formation of a microbe-inactivated, dehydrated layer of ~100 µm in thickness. Aerobic mesophilic bacteria, Enterobacteriaceae, yeast and mold on the treated samples are inactivated to a level below the detection limit and remained low during room temperature storage of 5 days. Meanwhile, the product quality, including visual appearance, texture, and nutrient level of the beef, remains mostly unchanged. In contrast, microorganisms grow rapidly on the untreated control samples, along with a rapid deterioration of the meat quality. This method might serve as a promising preservation technology for securing food safety and quality.
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Microbiología de Alimentos , Conservación de Alimentos , Animales , Bovinos , Conservación de Alimentos/métodos , Microbiología de Alimentos/métodos , Carne/microbiología , Calor , Carne Roja/microbiología , Calefacción , Inocuidad de los Alimentos/métodosRESUMEN
Colorectal cancer is the third leading cause of cancer incidence and mortality in the United States. Cannabidiol (CBD), the second most abundant phytocannabinoid in Cannabis sativa, has potential use in cancer treatment on the basis of many studies showing its anti-cancer activity in diverse types of cancer, including colon cancer. However, its mechanism of action is not yet fully understood. In the current study, we observed CBD to repress viability of different human colorectal cancer cells in a dose-dependent manner. CBD treatment led to G1-phase cell cycle arrest and an increased sub-G1 population (apoptotic cells); it also downregulated protein expression of cyclin D1, cyclin D3, cyclin-dependent kinase 2 (CDK2), CDK4, and CDK6. CBD further increased caspase 3/7 activity and cleaved poly(ADP-ribose) polymerase, and elevated expression of endoplasmic reticulum (ER) stress proteins including binding immunoglobulin protein (BiP), inositol-requiring enzyme 1α (IRE1α), phosphorylated eukaryotic initiation factor 2α (eIF2α), activating transcription factor 3 (ATF3), and ATF4. We found that CBD repressed cell viability and induced apoptotic cell death through a mechanism dependent on cannabinoid receptor type 2 (CB2), but not on CB1, transient receptor potential vanilloid, or peroxisome proliferator-activated receptor gamma. Anti-proliferative activity was also observed for other non-psychoactive cannabinoid derivatives including cannabidivarin (CBDV), cannabigerol (CBG), cannabicyclol (CBL), and cannabigerovarin (CBGV). Our data indicate that CBD and its derivatives could be promising agents for the prevention of human colorectal cancer.
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Cannabidiol , Neoplasias Colorrectales , Receptor Cannabinoide CB2/metabolismo , Cannabidiol/metabolismo , Cannabidiol/farmacología , Neoplasias Colorrectales/tratamiento farmacológico , Endorribonucleasas , Humanos , Proteínas Serina-Treonina Quinasas , Receptores de CannabinoidesRESUMEN
High-pressure processing (HPP) is a prevailing non-thermal food preservation technology. The inactivation mechanisms of Listeria monocytogenes under HPP at 200 and 400 MPa for 3 min were investigated by label-free quantitative proteomic analysis and functional enrichment analysis in the Kyoto Encyclopedia of Genes and Genomes. HPP treatment at 400 MPa exhibited significant effects on proteins involved in translation, carbon, carbohydrate, lipid and energy metabolism, and peptidoglycan biosynthesis. HPP increased most ribosomal subunits and initiation factors, suggesting it might shift ribosomal biogenesis to translation initiation. However, protein synthesis was impaired by the shortage of proteins responsible for elongation, termination and recycling. HPP stimulated several ATP-dependent Clp proteases, and the global transcriptional regulator Spx, associating with activation of the stress-activated sigma factor Sigma B (σB) and the transcriptional activator positive regulatory factor A (PrfA) regulons. The quantitative proteomics approaches provide fundamental information on L. monocytogenes under different HPP pressures, and provide theoretical support for HPP against Listeriosis illness and for promotion of safer ready-to-eat foods.
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Reducing crop losses due to fungal diseases requires improved understanding of the mechanisms governing plant immunity and fungal pathogenesis, which in turn requires accurate determination of disease phenotypes of plants upon infection with a particular fungal pathogen. However, accurate disease phenotyping with unculturable biotrophic fungal pathogens such as powdery mildew is not easy to achieve and can be a rate-limiting step of a research project. Here, we have developed a safe, efficient, and easy-to-operate disease phenotyping system using the Arabidopsis-powdery mildew interaction as an example. This system mainly consists of three components: (i) a wooden inoculation box fitted with a removable lid mounted with a stainless steel or nylon mesh of ~50 µm pores for inoculating a flat of plants with fungal spores, (ii) a transparent plastic chamber with a small front opening for minimizing spore escape while conducting inoculation inside, and (iii) a spore-dislodging and distribution method for even and effective inoculation. The protocols described here include the steps and parameters for making the inoculation box and the plastic chamber at a low cost, and a video demonstration of how to use the system to enable even inoculation with powdery mildew spores, thereby improving accuracy and reproducibility of disease phenotyping.
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Proteínas de Arabidopsis/genética , Arabidopsis/genética , Enfermedades de las Plantas/microbiologíaRESUMEN
Environmental contamination by microplastics (MPs) is an emerging concern in recent years due to associated adverse impacts of MPs on potential human health problems. Endothelial dysfunction is a condition in which the endothelial layer fails to form normally, and is associated with impaired vascular function. Despite the fact that MPs are known to enter the circulation system through intestinal epithelium, little has been known whether MPs impact the normal function of endothelial cells and the formation of vasculature. In the current study, we investigated the effect of polystyrene microplastics (PS-MPs) on tube formation and cytotoxicity in human umbilical vein endothelial cells (HUVECs). Our study showed that the treatment of HUVECs with PS-MPs significantly decreased cell viability, with intracellular accumulation occurring in a dose- and size-dependent manner. Moreover, significant dose-dependent inhibition of angiogenic tube formation was observed in HUVECs treated with 0.5 µm PS-MPs; this effect was accompanied by suppression of angiogenic signaling pathways and inhibitory activity against wound healing and cell migration. Regarding the mechanism of decreased viability, we observed increased autophagic and necrotic cell death. These results indicate that 6-h exposure of endothelial cells to PS-MPs represses tube-forming capacity, while 48-h exposure leads to autophagy and necrosis-mediated cytotoxicity.
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Supervivencia Celular/efectos de los fármacos , Microplásticos/toxicidad , Neovascularización Fisiológica/efectos de los fármacos , Poliestirenos/toxicidad , Animales , Autofagia/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Células Hep G2 , Células Endoteliales de la Vena Umbilical Humana , Humanos , Ratones , Necrosis/etiología , Transducción de Señal/efectos de los fármacosRESUMEN
The microwave-assisted induction heating (MAIH) system provides comprehensive heating by combining microwave heating (with 1300 W of power and 2450 MHz of frequency) in the top part and induction heating (with 1800 W of power) in the bottom part. In this study, fresh white shrimps were placed in a sealed crystallized polyethylene terephthalate (CPET) container and heated in the MAIH system at two temperatures (130 and 90 °C) from 60 to 120 s. Afterwards, the shrimp samples were rapidly cooled, and the changes in the shrimp quality, including the appearance, cook loss, aerobic plate count (APC), color values, and texture, during the heating process were analyzed. The results demonstrate that longer heating times decrease the APC levels, but increase the cook loss, color values (lightness, redness, and whiteness), and texture (hardness, cohesiveness and chewiness) of the white shrimp samples. In particular, the white shrimp is fully cooked and gains a completely red appearance, along with no APC detected after heating in the MAIH system at 130 °C for at least 80 s or at 90 °C for at least 100 s. In summary, to achieve a good appearance, no APC detected, and low cook loss, the following heating conditions are recommended for cooking white shrimp in the MAIH system: heating at 130 °C for 80 s or at 90 °C for 100 s. This novel MAIH technology allows food to be heated and sterilized after being packed, thereby eliminating the post-pollution issue. To the best of the authors' knowledge, this is the first study to evaluate the use of MAIH in the application of food processing.
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The inactivation and damage of histamine-forming bacteria (HFB), Enterobacter aerogenes and Staphylococcus capitis, in a 0.1 M potassium phosphate buffer (pH 6.8) and marlin meat slurry by high hydrostatic pressure (HHP) treatments were studied using viability measurement and scanning electron microscopy (SEM). HHP treatments showed first order destruction kinetics to E. aerogenes and S. capitis during the pressure holding period. HFB in marlin meat slurry had higher D values and were more resistant to HHP treatments than in phosphate buffer. In phosphate buffer, E. aerogenes had higher D values than S. capitis at >380 MPa of pressure, whereas the reverse trend was noticed at lower pressures (<380 MPa). In marlin meat slurry, S. capitis had a higher D value than E. aerogenes at the same treatment pressure, indicating that S. capitis was more resistant to HHP treatment. To our knowledge, this is the first report to demonstrate that HHP can be used to inactivate HFB, E. aerogenes, and S. capitis, by causing disruption to bacterial cell membrane and cell wall as demonstrated by SEM micrographs.
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The molecular mechanism of biofilm formation by Salmonella Typhimuriun DT104 was characterized for a better understanding of its attachment and colonization in food processing environments. A library of random mutagenized clones was screened for phenotypic analyses of their ability to form biofilm, pellicle, curli, and cellulose. The genes identified were involved in lipopolysaccharide synthesis, assembly of flagella, regulation of rRNA biosynthesis, and outer membrane transportation and signaling. The insertion of transposon in flgK, rfbA, nusB, and pnp genes resulted in decreased biofilm formation. Alterations of flagellar and lipopolysaccharide production were confirmed in the flgK mutant and rfbA mutant, respectively. Biofilm formation by these four mutants in meat and poultry broths and their attachment on surfaces of stainless steel and glass were significantly reduced compared with those of the wild-type strain (P < 0.05). On the contrary, the mutation of STM4263 and yjcC genes in Salmonella Typhimuriun DT104 resulted in increased biofilm formation and attachment of the species in tested broths and on contact surfaces. Our findings suggest that many factors, such as production of exopolymeric substances and their efficient transportation through outer membrane, expression of flagella, and regulation of exoribonucleases and RNA-binding protein, could be involved in biofilm formation and attachment of Salmonella Typhimurium DT104 on contact surfaces.
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Proteínas Bacterianas/metabolismo , Biopelículas/crecimiento & desarrollo , Contaminación de Equipos , Contaminación de Alimentos/análisis , Salmonella typhimurium/fisiología , Adhesión Bacteriana/fisiología , Proteínas Bacterianas/genética , Celulosa/metabolismo , Recuento de Colonia Microbiana , Elementos Transponibles de ADN , ADN Bacteriano/análisis , Regulación Bacteriana de la Expresión Génica , Lipopolisacáridos/metabolismo , Mutación , Fenotipo , Salmonella typhimurium/genéticaRESUMEN
Multistate outbreaks of Escherichia coli O157:H7 infections through consumption of contaminated foods including produce products have brought a great safety concern. The objectives of this study were to determine the effect of biofilm and quorum sensing production on the attachment of E. coli O157:H7 on food contact surfaces and to evaluate the transfer of the pathogen from the food contact to various food products. E. coli O157:H7 produced maximum levels of AI-2 signals in 12 h of incubation in tested meat, poultry, and produce broths and subsequently formed strong biofilm in 24 h of incubation. In general, E. coli O157:H7 formed stronger biofilm on stainless steel than glass. Furthermore, E. coli O157:H7 that had attached on the surface of stainless steel was able to transfer to meat, poultry, ready-to-eat deli, and produce products. Strong attachment of the transferred pathogen on produce products (cantaloupe, lettuce, carrot, and spinach) was detected (>10(3) CFU/cm2) even after washing these products with water. Our findings suggest that biofilm formation by E. coli O157:H7 on food contact surfaces can be a concern for efficient control of the pathogen particularly in produce products that require no heating or cooking prior to consumption.
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Adhesión Bacteriana/fisiología , Biopelículas/crecimiento & desarrollo , Escherichia coli O157/fisiología , Contaminación de Alimentos/análisis , Percepción de Quorum , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Microbiología Ambiental , Contaminación de Alimentos/prevención & control , Frutas/microbiología , Vidrio , Carne/microbiología , Productos de la Carne/microbiología , Acero Inoxidable , Factores de Tiempo , Verduras/microbiologíaRESUMEN
The effect of polyethylene packaging (PEP) in air cushion and vacuum packaging (VP) on histamine related to the quality of Japanese Spanish mackerel (JS mackerel) was studied with samples stored at -20, 4, 15, and 25°C. The aerobic plate count (APC), total volatile basic nitrogen (TVBN), and histamine concentrations of the PEP and VP samples stored at 25°C increased as the storage time continued. The PEP and VP samples stored at temperatures below 15°C showed lower levels of APC, TVBN, and histamine, with VP samples having considerably lower levels of APC, TVBN, and histamine than PEP samples. For the frozen JS mackerel stored at -20°C for 2 months and then thawed and stored at 25°C, the VP treatment delayed the increases of TVBN and histamine longer than did the PEP treatment. Thus, the storage of VP JS mackerel at temperatures below 4°C could prevent quality deterioration and extend shelf life.
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Embalaje de Alimentos , Histamina , Perciformes , Temperatura , Animales , Embalaje de Alimentos/normas , Histamina/análisis , Histamina/metabolismo , Japón , Perciformes/microbiología , VacioRESUMEN
Bubble tea beverages (n = 105) purchased from vendors in Taiwan were tested to determine their microbiological and chemical quality. Nearly half of the tested samples (48.6%, 51 of 105) had aerobic plate counts (APCs) higher than the Taiwan Food and Drug Administration guideline of 4.0 log CFU/mL, and 55 (52.4%) had coliform counts (most probable number [MPN]) higher than the 10 MPN/mL guideline. Escherichia coli, Salmonella, Staphylococcus aureus, sweeteners, preservatives, maleic acid, and coumarin were not detected in any sample. However, catechins were not detected to 188 mg/mL, and caffeine was 10.1 to 457.6 mg/mL. Bubble tea samples obtained from vendors in southern Taiwan had a mean APC of 2.6 log CFU/mL and a mean coliform count of 61.7 MPN/mL; these values were significantly lower (P < 0.05) than those from samples collected from vendors in northern, eastern, or central Taiwan. Samples obtained from southern Taiwan had the highest mean catechin concentrations of 21.3 mg/mL (P < 0.05). About 60% (63 of 105) of the bubble tea samples were not labeled with the origin of the tea leaves, which is in violation of Taiwanese food labeling regulations. In general, the bubble tea beverages tested had satisfactory microbial and chemical qualities.
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Bebidas , Microbiología de Alimentos , Té , Bebidas/análisis , Catequina/análisis , Recuento de Colonia Microbiana , Análisis de los Alimentos , Taiwán , Té/microbiologíaRESUMEN
The potential pathogenicity of Pseudomonas aeruginosa isolates from food animals, retail meat products, and food processing environments was evaluated by determining their antibiotic resistance profiles and invasiveness into human intestinal Caco-2 cell. In general, the genomically diversified isolates of P. aeruginosa were resistant to beta-lactams (ampicillin, amoxicillin-clavulanic acid, cefoxitin, ceftiofur, and cephalothin), chloramphenicol, tetracycline, kanamycin, nalidixic acid, and sulfamethoxazole-trimethoprim. Acquisition of any other antibiotic resistance genes, such as class 1 integrons and other beta-lactamase genes, was not found in the tested isolates. The expression of OprM membrane protein, which is associated with a multidrug efflux system, played a major role in their antibiotic resistance. Single mutation in the GyrA to confer resistance to nalidixic acids was also found in the tested isolates, indicating that these factors could synergistically affect the resistance of the P. aeruginosa isolates. The number of bacteria invading into the Caco-2 cells was 2.5 log(10) CFU/ml on average. Therefore, the public health concern of P. aeruginosa could be relevant since its occurrence in food animals could cross contaminate the retail meat products during food handling and processing.
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Antibacterianos/farmacología , Adhesión Bacteriana , Farmacorresistencia Bacteriana , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Animales , Células CACO-2/microbiología , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Farmacorresistencia Bacteriana/genética , Microbiología Ambiental , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Humanos , Productos de la Carne/microbiología , Pruebas de Sensibilidad MicrobianaRESUMEN
The biofilm-forming capability of Salmonella enterica serotypes Typhimurium and Heidelberg, Pseudomonas aeruginosa, Listeria monocytogenes, Escherichia coli O157:H7, Klebsiella pneumoniae, and Acinetobacter baumannii isolated from humans, animal farms, and retail meat products was evaluated by using a microplate assay. The tested bacterial species showed interstrain variation in their capabilities to form biofilms. Strong biofilm-forming strains of S. enterica serotypes, E. coli O157: H7, P. aeruginosa, K. pneumoniae, and A. baumannii were resistant to at least four of the tested antibiotics. To understand their potential in forming biofilms in food-processing environments, the strong biofilm formers grown in beef, turkey, and lettuce broths were further investigated on stainless steel and glass surfaces. Among the tested strains, Salmonella Typhimurium phage type DT104 (Salmonella Typhimurium DT104) isolated from retail beef formed the strongest biofilm on stainless steel and glass in beef and turkey broths. K. pneumoniae, L. monocytogenes, and P. aeruginosa were also able to form strong biofilms on the tested surface materials. Salmonella Typhimurium DT104 developed a biofilm on stainless steel in beef and turkey broths through (i) initial attachment to the surface, (ii) formation of microcolonies, and (iii) biofilm maturation. These findings indicated that Salmonella Typhimurium DT104 alongwith other bacterial pathogens could be a source of cross-contamination during handling and processing of food.
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Antibacterianos/farmacología , Adhesión Bacteriana/fisiología , Farmacorresistencia Bacteriana , Industria de Procesamiento de Alimentos/normas , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/fisiología , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/fisiología , Animales , Biopelículas/crecimiento & desarrollo , Recuento de Colonia Microbiana , Contaminación de Equipos , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/fisiología , Contaminación de Alimentos , Manipulación de Alimentos/métodos , Industria de Procesamiento de Alimentos/métodos , Vidrio , Humanos , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/fisiología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/fisiología , Productos de la Carne/microbiología , Pruebas de Sensibilidad Microbiana , Especificidad de la Especie , Acero InoxidableRESUMEN
Interaction of Escherichia coli O157:H7/pGFP with hydroponically grown lettuce plants was evaluated in this study. Lettuce seedlings were planted in contaminated Hoagland's nutrient solution and thereafter subjected to gamma radiation at 0.25, 0.5, and 0.75 kGy, and aqueous chlorine at 200 ppm. There was no trace of E. coli O157:H7/pGFP in lettuce leaves harvested from noncontaminated nutrient solution (control); however, for plants grown in contaminated nutrient solution, the pathogen was recovered from the leaves disinfected with 80% ethanol and 0.1% mercuric chloride. Most of the lettuce seedlings grown in contaminated nutrient solution tested negative for E. coli O157:H7/pGFP under controlled conditions. Gamma radiation at 0.25 and 0.5 kGy, and aqueous chlorine at 200 ppm failed to eliminate E. coli O157:H7/pGFP in lettuce tissue completely; however, the bacteria were not detected in 0.75-kGy treated plants. The presence of E. coli O157:H7/pGFP in lettuce leaves is an indication that the pathogen migrated from the contaminated hydroponic system through the roots to the internal locations of lettuce tissue. Due to inaccessibility and limited penetrating power, aqueous chlorine could not eliminate the bacteria localized in the internal tissue. Findings from this study suggest that gamma irradiation was more efficacious than was aqueous chlorine to control internal contamination in hydroponically grown lettuce. Gamma irradiation is a process that processors can use to inactivate E. coli O157:H7 and therefore, consumers benefit from a safer food product [corrected]
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Compuestos de Cloro/farmacología , Escherichia coli O157/efectos de la radiación , Irradiación de Alimentos/métodos , Rayos gamma , Lactuca/microbiología , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Relación Dosis-Respuesta en la Radiación , Escherichia coli O157/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Contaminación de Alimentos/prevención & control , Microbiología de Alimentos , HidroponíaRESUMEN
The risk of cardiovascular disease drastically increases at the onset of menopause, in part, because of rise in blood cholesterol and unfavorable changes in lipid profile. This study was designed to investigate the dose-dependent effects of vitamin E supplementation on lipid parameters in ovariectomized (ovx) rats. Sixty 12-month-old female Sprague-Dawley rats were either sham-operated (sham; one group) or ovx (four groups). All rats were maintained on a semipurified caseinbased diet (AIN-93M; 75 IU vitamin E/kg of diet) for a period of 120 days. Thereafter, ovx rats were placed on one of four doses of vitamin E treatment (75, 300, 525, or 750 IU vitamin E/kg of diet), while the sham group was continued on 75 IU vitamin E/kg of diet for 100 days. Ovariectomy tended to increase (by 24%, P = 0.1) serum non?high-density lipoprotein (HDL) cholesterol and decrease (by 14%, P = 0.1) HDL cholesterol. Vitamin E did not have any significant effects on serum lipid parameters. Liver total lipids were notably increased (P < .001) in ovx animals, and supplementation with vitamin E at 525 IU/kg of diet was able to significantly reduce liver total lipids by 13%. Additionally, ovariectomy caused an increase in serum glucose and liver C18:1 fatty acid concentrations along with decreases in C18:0, C20:4, and C22:6 fatty acid concentrations. These alterations on liver fatty acid profiles were unaffected by vitamin E. The findings of this study suggest that vitamin E supplementation moderately improves lipid parameters in ovarian hormone-deficient rats.
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Lípidos/sangre , Ovariectomía , Vitamina E/administración & dosificación , Animales , Glucemia/análisis , Peso Corporal , Caseínas/administración & dosificación , Colesterol/análisis , Colesterol/sangre , HDL-Colesterol/sangre , Dieta , Ácidos Grasos/análisis , Femenino , Compuestos Férricos/química , Riñón/anatomía & histología , Lípidos/análisis , Hígado/anatomía & histología , Hígado/química , Hígado/efectos de los fármacos , Tamaño de los Órganos , Oxidación-Reducción , Ratas , Ratas Sprague-Dawley , Triglicéridos/sangreRESUMEN
Sixty-four multidrug-resistant isolates of Proteus mirabilis were collected from retail meat products in Oklahoma. The isolates showed four different patterns of antibiotic resistance based on their resistant phenotype and genotypes. Most of these isolates were resistant to ampicillin, tetracycline, gentamycin, and kanamycin. Class 1 integrons were detected as a common carrier of the antibiotic-resistant genes, such as aadA1, aadB, and aadA2. A few isolates (9%) contained class 2 integrons with three gene cassettes included: dhfr1, sat1, and aadA1. These isolates were even resistant to nalidixic acid due to mutations in gyrA and parC. All ampicillin-resistant isolates contained blaTEM-1. Plasmids that contained class 1 or 2 integrons and blaTEM-1 were able to be transferred from P. mirabilis isolates into Escherichia coli by conjugation, indicating that conjugal transfer could contribute to the dissemination of antibiotic resistance genes between the Enterobacteriaceae species.