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Fecal suspensions with an aerosol route of transmission were responsible for a cluster of severe acute respiratory syndrome (SARS) cases in 2003 in Hong Kong. Based on that event, the World Health Organization recommended that research be implemented to define modes of transmission of SARS coronavirus through sewage, feces, food and water. Environmental studies have shown that animal coronaviruses remain infectious in water and sewage for up to a year depending on the temperature and humidity. In this study, we examined coronavirus stability on lettuce surfaces. A cell culture adapted bovine coronavirus, diluted in growth media or in bovine fecal suspensions to simulate fecal contamination was used to spike romaine lettuce. qRT-PCR detected viral RNA copy number ranging from 6.6 × 104 to 1.7 × 106 throughout the experimental period of 30 days. Whereas infectious viruses were detected for at least 14 days, the amount of infectious virus varied, depending upon the diluent used for spiking the lettuce. UV and confocal microscopic observation indicated attachment of residual labeled virions to the lettuce surface after the elution procedure, suggesting that rates of inactivation or detection of the virus may be underestimated. Thus, it is possible that contaminated vegetables may be potential vehicles for coronavirus zoonotic transmission to humans. 相似文献
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Elisa Bellan Menegussi;Sheila Montipó;Roselei Claudete Fontana;Suelen Paesi;Marli Camassola; 《Biofuels, Bioproducts and Biorefining》2024,18(1):237-250
During the normal production of ethanol from pretreated lignocellulosic biomass, only the solid fraction containing C6 sugars is generally used by unmodified yeasts in the fermentation process – the remaining liquid fraction, rich in xylose, is used almost exclusively by genetically modified organisms (GMOs) or for other purposes. As the liquor can be used in the manufacture of a series of chemical inputs, microorganisms that metabolize C5 sugars from different sources were initially isolated with the aim of converting these sugars into acetic acid (AA) and lactic acid (LA). Experiments were carried out with pretreated elephant grass liquor, evaluating the effect of adding commonly referenced nutrients through experimental design. Thus, the present work involves the isolation, screening, and molecular characterization of bacteria, easily found in nature, with the potential to metabolize xylose and produce AA and LA, with yields similar or superior to those shown in studies employing GMOs. Using wild-type strains, high yields were obtained with Acetobacter cerevisiae (0.96 g LA and 0.71 g AA per g total sugars) and Levilactobacillus brevis (0.77 g LA and 0.61 g AA per g total sugars) in relation to the organic acids of interest, highlighting the total conversion of the sugar blend (xylose, glucose, and arabinose) in 24 h. Ammonium citrate also significantly influenced the final yields, being responsible for the increase in production. The results are useful for biorefinery platforms and may contribute to the full use of sugars released in the lignocellulosic pretreatment of raw materials. 相似文献
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Johanna Saunier Christian Marlière Alexandre Dazzi Ariane Deniset-Besseau Najet Yagoubi 《应用聚合物科学杂志》2020,137(43):49324
Several commercial infusion tubes made of plasticized poly(vinyl chloride) were shown to present a layer of bloomed species on their internal wall (lubricants and stabilizers), which are poorly soluble in water. During infusion, tubes are crushed and pinched to regulate the flow. The impact of mechanical stress on these layers infusion was studied. Device inner surfaces were characterized by atomic force microscopy in order to put into evidence surface degradations before and after infusion. This was correlated with a global and local infrared analysis. Because of the clamp stress, the deposits were damaged. Thus, injecting water into the damaged tubing increased the layer degradation. Roller clamp and pinch clamp may have very different effects on the inner layer morphology and degradation and this may be modulated by the initial layer morphology. Injecting water into clamp stressed tubing may increase the risk of detaching parts of the internal layer and be a supplementary factor of particulate contamination for the patient. 相似文献
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Dr. Cécile Gasse Dr. Puneet Srivastava Guy Schepers Prof. Joachim Jose Dr. Marcel Hollenstein Dr. Philippe Marlière Prof. Piet Herdewijn 《Chembiochem : a European journal of chemical biology》2023,24(15):e202300191
Chemical cell surface modification is a fast-growing field of research, due to its enormous potential in tissue engineering, cell-based immunotherapy, and regenerative medicine. However, engineering of bacterial tissues by chemical cell surface modification has been vastly underexplored and the identification of suitable molecular handles is in dire need. We present here, an orthogonal nucleic acid-protein conjugation strategy to promote artificial bacterial aggregation. This system gathers the high selectivity and stability of linkage to a protein Tag expressed at the cell surface and the modularity and reversibility of aggregation due to oligonucleotide hybridization. For the first time, XNA (xeno nucleic acids in the form of 1,5-anhydrohexitol nucleic acids) were immobilized via covalent, SNAP-tag-mediated interactions on cell surfaces to induce bacterial aggregation. 相似文献
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Rômulo Dias Novaes Priscila Lima Sequetto Reggiani Vilela Gonçalves Marli Carmo Cupertino Eliziária Cardoso Santos Vanessa Joia Mello Marta Rocha Araújo Edson Silva Tânia Toledo Oliveira 《Microscopy research and technique》2016,79(1):3-13
This study investigated the relationship between enteroendocrine and mucus‐secreting cells distribution, the severity of colonic mucosal injury and intestinal motility in experimental colorectal carcinogenesis. Using a standardized murine model of colorectal carcinogenesis, eight‐weeks‐old female Wistar rats weighting 147.30 ± 29.15g were randomized into two groups receiving a subcutaneous injection of 0.9% saline (control) or the chemical carcinogen 1,2‐dimethylhydrazine (DMH) at 20 mg/kg per week during 10 weeks. Aberrant crypt foci (ACF) were more frequent in DMH group compared to control group (P < 0.001). The number of enteroendocrine and mucus‐secreting cells, and intestinal motility was reduced in DMH animals (P < 0.05). The distribution of enteric neurons was similar in both groups. In DMH animals there was a direct correlation between colonic motility and distribution of enteroendocrine (R2 = 0.68, P < 0.05) and mucus‐secreting cells (R2 = 0.77, P < 0.05). Inverse correlation between the number of ACF, mucus‐secreting cells (R2 = ?0.57, P < 0.05), and enteroendocrine cells (R2 = ?0.74, P < 0.05) was also observed. There was inverse correlation between the severity of the mucosal lesion, the number of mucus‐secreting cells (R2 = ?0.83, P < 0.05) and enteroendocrine cells (R2 = ?0.96, P < 0.05). There was a direct correlation between nucleolar organizer regions (AgNOR) and ACF number (R2 = 0.62; P < 0.01). Inverse correlation was also found between AgNOR, the number of mucus‐secreting cells (R2 = ?0.76; P < 0.001), and enteroendocrine cells (R2 = ?0.86; P < 0.001). Taken together, the results indicated that colonic malignant transformation is related to depletion of mucus‐secreting and enteroendocrine cells, which was a useful indicator of the evolutionary status of intestinal neoplasm, partially explaining the intestinal motility disorders in the early stages of colorectal carcinogenesis. Microsc. Res. Tech. 79:3–13, 2016. © 2015 Wiley Periodicals, Inc. 相似文献