RESUMEN
This study aimed to determine whether oral fumonisin exposure contributes to the development of psoriasis. Oral administration of fumonisin B1 (FB1, 0.1 mg/kg) or fumonisin B2 (FB2, 0.1 mg/kg) was conducted for 10 days, in addition to the induction of psoriatic symptoms through topical application of 5% imiquimod cream from day 6 to day 10 (5 days) in female BALB/c mice. The results demonstrated that oral administration of FB2 significantly exacerbated psoriatic symptoms, including skin thickness, itching behavior, transepidermal water loss, immune cell infiltration in the dermis, and proinflammatory cytokine production. However, no changes were observed following exposure to FB1. Our results confirm that oral exposure to FB2 adversely affects the pathogenesis of psoriasis by increasing skin thickness and impairing barrier function.
Asunto(s)
Fumonisinas , Imiquimod , Ratones Endogámicos BALB C , Psoriasis , Animales , Psoriasis/inducido químicamente , Psoriasis/patología , Psoriasis/metabolismo , Imiquimod/efectos adversos , Fumonisinas/toxicidad , Ratones , Femenino , Administración Oral , Piel/efectos de los fármacos , Piel/metabolismo , Piel/patología , Citocinas/metabolismo , Modelos Animales de EnfermedadRESUMEN
A foodborne outbreak related to milk cartons served in school lunches occurred in June 2021, which involved more than 1,800 cases from 25 schools. The major symptoms were abdominal pain, diarrhoea, vomiting, and fever. Although major foodborne toxins and pathogens were not detected, a specific Escherichia coli strain, serotype OUT (OgGp9):H18, was predominantly isolated from milk samples related to the outbreak and most patients tested. The strains from milk and patient stool samples were identified as the same clone by core genome multilocus sequence typing and single-nucleotide polymorphism analysis. The strain was detected in milk samples served for two days related to the foodborne outbreak at a rate of 69.6% and levels of less than ten most probable number/100 mL but not on days unrelated to the outbreak. The acid tolerance of the strain for survival in the stomach was similar to that of enterohaemorrhagic E. coli O157:H7, and the same inserts in the chu gene cluster in the acid fitness island were genetically revealed. The pathogenicity of the strain was not clear; however, it was indicated that the causative pathogen was atypical diarrhoeagenic E. coli OUT (OgGp9):H18.
Asunto(s)
Dolor Abdominal , Diarrea , Infecciones por Escherichia coli , Escherichia coli O157 , Animales , Humanos , Dolor Abdominal/etiología , Brotes de Enfermedades , Escherichia coli Enterohemorrágica , Leche/microbiología , Diarrea/epidemiología , Diarrea/microbiología , Japón/epidemiología , Infecciones por Escherichia coli/epidemiologíaRESUMEN
Contamination with fumonisins produced by Fusarium spp. is rapidly growing in both developing and developed countries. The purpose of this study was to determine whether oral exposure to fumonisin contributed to the development of allergic diseases. We initially examined the immunotoxic potential of short-term, oral administration of fumonisin B1 (FB1, 1 mg/kg) and fumonisin B2 (FB2, 1 mg/kg), both naturally occurring fumonisins, using a BALB/c mouse model of allergic contact dermatitis and Dermatophagoides farina-induced asthma. Using an NC/nga mouse model of atopic dermatitis (AD), we evaluated the adverse effects of subchronic oral exposure to low concentrations of FB2 (2 or 200 µg/kg). Finally, we explored the influence of FB2 on regulatory T cell proliferation and function in mesenteric lymph nodes after 1-week oral exposure to FB2 in BALB/c mice. Oral exposure to FB2 markedly exacerbated the symptoms of allergy, including skin thickness, histological evaluation, immunocyte proliferation, and proinflammatory cytokine production, although no change was observed following exposure to FB1. Furthermore, oral exposure to low concentrations of FB2 considerably exacerbated the AD scores, skin thickness, transepidermal water loss, histological features, and proinflammatory cytokine production. The aggravated allergic symptoms induced by oral exposure to FB2 could be attributed to the direct inhibition of IL-10 production by regulatory T cells in mesenteric lymph nodes. Our findings indicate that the recommended maximum fumonisin level should be reconsidered based on the potential for allergy development.
Asunto(s)
Dermatitis Alérgica por Contacto , Fumonisinas , Animales , Ratones , Fumonisinas/toxicidad , Interleucina-10 , Linfocitos T Reguladores , Ganglios LinfáticosRESUMEN
The most common diagnostic method used for coronavirus disease-2019 (COVID-19) is real-time reverse transcription polymerase chain reaction (PCR). However, it requires complex and labor-intensive procedures and involves excessive positive results derived from viral debris. We developed a method for the direct detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swabs, which uses matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-ToF MS) to identify specific peptides from the SARS-CoV-2 nucleocapsid phosphoprotein (NP). SARS-CoV-2 viral particles were separated from biological molecules in nasopharyngeal swabs by an ultrafiltration cartridge. Further purification was performed by an anion exchange resin, and purified NP was digested into peptides using trypsin. The peptides from SARS-CoV-2 that were inoculated into nasopharyngeal swabs were detected by MALDI-ToF MS, and the limit of detection was 106.7 viral copies. This value equates to 107.9 viral copies per swab and is approximately equivalent to the viral load of contagious patients. Seven NP-derived peptides were selected as the target molecules for the detection of SARS-CoV-2 in clinical specimens. The method detected between two and seven NP-derived peptides in 19 nasopharyngeal swab specimens from contagious COVID-19 patients. These peptides were not detected in four specimens in which SARS-CoV-2 RNA was not detected by PCR. Mutated NP-derived peptides were found in some specimens, and their patterns of amino acid replacement were estimated by accurate mass. Our results provide evidence that the developed MALDI-ToF MS-based method in a combination of straightforward purification steps and a rapid detection step directly detect SARS-CoV-2-specific peptides in nasopharyngeal swabs and can be a reliable high-throughput diagnostic method for COVID-19.
Asunto(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , Rayos Láser , Nasofaringe , ARN Viral/genética , Manejo de Especímenes/métodos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodosRESUMEN
This study evaluated the ability of selected strains of Trichoderma viride, T. viridescens, and T. atroviride to inhibit mycelium growth and the biosynthesis of mycotoxins deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEN), α-(α-ZOL) and ß-zearalenol (ß-ZOL) by selected strains of Fusarium culmorum and F. cerealis. For this purpose, an in vitro experiment was carried out on solid substrates (PDA and rice). After 5 days of co-culture, it was found that all Trichoderma strains used in the experiment significantly inhibited the growth of Fusarium mycelium. Qualitative assessment of pathogen-antagonist interactions showed that Trichoderma colonized 75% to 100% of the medium surface (depending on the species and strain of the antagonist and the pathogen) and was also able to grow over the mycelium of the pathogen and sporulate. The rate of inhibition of Fusarium mycelium growth by Trichoderma ranged from approximately 24% to 66%. When Fusarium and Trichoderma were co-cultured on rice, Trichoderma strains were found to inhibit DON biosynthesis by about 73% to 98%, NIV by about 87% to 100%, and ZEN by about 12% to 100%, depending on the pathogen and antagonist strain. A glycosylated form of DON was detected in the co-culture of F. culmorum and Trichoderma, whereas it was absent in cultures of the pathogen alone, thus suggesting that Trichoderma is able to glycosylate DON. The results also suggest that a strain of T. viride is able to convert ZEN into its hydroxylated derivative, ß-ZOL.
Asunto(s)
Fusarium , Micotoxinas , Oryza , Trichoderma , Tricotecenos , Zearalenona , Zearalenona/farmacologíaRESUMEN
The t-type trichothecene producers Fusarium sporotrichioides and Fusarium graminearum protect themselves against their own mycotoxins by acetylating the C-3 hydroxy group with Tri101p acetylase. To understand the mechanism by which they deal with exogenously added d-type trichothecenes, the Δtri5 mutants expressing all but the first trichothecene pathway enzymes were fed with trichodermol (TDmol), trichothecolone (TCC), 8-deoxytrichothecin, and trichothecin. LC-MS/MS and NMR analyses showed that these C-3 unoxygenated trichothecenes were conjugated with glucose at C-4 by α-glucosidic linkage. As t-type trichothecenes are readily incorporated into the biosynthetic pathway following the C-3 acetylation, the mycotoxins were fed to the ΔFgtri5ΔFgtri101 mutant to examine their fate. LC-MS/MS and NMR analyses demonstrated that the mutant conjugated glucose at C-4 of HT-2 toxin (HT-2) by α-glucosidic linkage, while the ΔFgtri5 mutant metabolized HT-2 to 3-acetyl HT-2 toxin and T-2 toxin. The 4-O-glucosylation of exogenously added t-type trichothecenes appears to be a general response of the ΔFgtri5ΔFgtri101 mutant, as nivalenol and its acetylated derivatives appeared to be conjugated with hexose to some extent. The toxicities of 4-O-glucosides of TDmol, TCC, and HT-2 were much weaker than their corresponding aglycons, suggesting that 4-O-glucosylation serves as a phase II xenobiotic metabolism for t-type trichothecene producers.
Asunto(s)
Fusarium/metabolismo , Glucosa/metabolismo , Fase II de la Desintoxicación Metabólica , Tricotecenos/metabolismo , Acetilación , Cromatografía Liquida , Espectrometría de Masas en TándemRESUMEN
Fumonisins, which are secondary metabolites produced by some Fusarium species, are detected mainly in corn and corn-based products. Recently, the presence of modified forms of fumonisins in fumonisin-contaminated food products has been reported. In order to evaluate the health risk of modified forms of fumonisins to the Japanese population, we analyzed modified forms of fumonisins in corn-based products retailed in Japan. The modified and free forms of fumonisins in food samples were hydrolyzed by alkaline treatment. The resulting hydrolyzed fumonisins were quantified by LC-MS/MS, and total fumonisins (sum of modified and free forms) was calculated. A total of 166 samples of corn-based products were analyzed over two years. The relative ratios of mean total fumonisins to mean free fumonisins in the cornflakes, corn snacks, corn flour and powdered corn soup samples were 4.7, 2.8, 2.1 and 1.2, respectively. Total fumonisins in the residual solid of five cornflake and three corn snack samples obtained after extraction with methanol-water (3 : 1) were quantified. In the cornflakes and corn snacks samples, 56-72 and 83-98% of the modified forms of fumonisins were present in the residual solid, respectively. The average daily intake of fumonisins from cornflakes and corn snacks by the Japanese population was estimated at 1.1 to 3.9 ng/kg body weight/day when the results of free fumonisins were used for the estimate, but when the results of total fumonisins were used, average daily intake increased about three times and was estimated at 3.3 to 12.5 ng/kg body weigh/day. These results indicate that a risk assessment of fumonisins, including the modified forms of fumonisins, is necessary in order to evaluate the true risk of fumonisins to Japanese people.
Asunto(s)
Análisis de los Alimentos , Contaminación de Alimentos , Fumonisinas , Zea mays , Cromatografía Liquida , Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Fumonisinas/análisis , Hidrólisis , Japón , Espectrometría de Masas en Tándem , Zea mays/químicaRESUMEN
We screened 360 chemicals and discovered that 71 chemicals had anti-Kudoa septempunctata effect. Especially 19 and seven of 71 chemicals were antibiotics and antibacterial agents/disinfectants, respectively. The other 45 chemicals were pesticides, natural toxins, industrial chemicals and medicines for non-infectious diseases. Nineteen antibiotics that possessed anti-Kudoa effect contained four tetracyclines, one steroid, two macrolides, one aminoglycoside, three ß-lactams, one quinolone, two rifamycines, one polyene, one novobiocine, one sulfonamide and two nitroimidazoles. To use these drugs for prevention of Kudoa infection, the further study is need for the determination of effective dose.
Asunto(s)
Antiparasitarios , Descubrimiento de Drogas , Enfermedades Transmitidas por los Alimentos , Myxozoa , Animales , Antiparasitarios/química , Antiparasitarios/farmacología , Antiparasitarios/uso terapéutico , Bioensayo , Myxozoa/efectos de los fármacos , Enfermedades Parasitarias/tratamiento farmacológicoRESUMEN
The inhibition of Kudoa septempunctata by green tea extract, black tea extract, and coffee extract were studied. Incubation of about 104 Kudoa spores with green tea extract, black tea extract, or coffee extract at 25â for 4 hr reduced the survival ratio of Kudoa to 0%. While coffee extract and green tea extract contain approximately 2 and 1 mM of caffeine, respectively, the incubation of Kudoa spores with 2 and 1 mM of caffeine reduced its survival ratio to 68.2 and 93.3%, respectively. Although green tea extract and black tea extract contain over 1 mM of catechin, incubation with 0.01 mM of catechin was enough to reduce the survival ratio of Kudoa to 20%. These results suggested that green tea extract, black tea extract, and coffee extract have strong inhibitory effects on Kudoa and the effects of green tea extract and black tea extract are mainly manifested through catechin.
Asunto(s)
Myxozoa , Animales , Cafeína , Catequina , Café , TéRESUMEN
Kudoa septempunctata, a myxosporean parasite, is the causative agent of a foodborne illness associated with consumption of raw Paralichthys olivaceus (olive flounder). Because the lag phase of this illness is short (from 1 to 12 h), it is possible that an allergic response is relevant to this illness. To test whether a K. septempunctata antigen is the possible allergen, we injected a myxospore extract into BALB/c mice and measured IgE levels in serum. When the mice were injected with the myxospore extract, the total serum IgE concentration increased significantly after the second immunization as compared to the negative control. After the third immunization, total IgE concentration in the immunized mice reached 26.5 ng/ml and was almost equivalent to that of egg albumin-injected mice. Western blot analysis revealed that IgE antibodies-in serum samples that were collected from myxospore extract-injected mice-bound to at least two Kudoa proteins with molecular weight between 28 and 36 kDa. These results suggested that a K. septempunctata antigen is the allergen. Further studies are needed to clarify the contribution of allergy to the foodborne illness caused by K. septempunctata.
Asunto(s)
Lenguado/parasitología , Hipersensibilidad a los Alimentos/inmunología , Enfermedades Transmitidas por los Alimentos/parasitología , Inmunoglobulina E/sangre , Myxozoa/inmunología , Enfermedades Parasitarias/parasitología , Animales , Antígenos/inmunología , Hipersensibilidad a los Alimentos/parasitología , Ratones , Ratones Endogámicos BALB C , Organismos Libres de Patógenos EspecíficosRESUMEN
Cryopreservation methods for Kudoa septempunctata have not been established. This prevents an effective study of K. septempunctata, which cannot be artificially cultivated in the laboratory. In this study, we attempted to establish a cryopreservation method for K. septempunctata sporoplasm using Cellbanker® 1, a commercial preservation medium for mammalian cells. Spores were purified from the meat of Paralichthys olivaceus (olive flounder). These purified spores were suspended in Cellbanker® 1 and were stored at -80 °C for up to 16 months. Although the spores stored at -80 °C for 16 months were damaged, the sporoplasms maintained its amoeba-like indeterminate morphology, and their motility was well preserved. The viability of sporoplasms was variable among vials but was not below 70 %. In addition, the sporoplasms stored at -80 °C for 16 months could decrease the transepithelial electrical resistance of Caco-2 cells. These results indicate that this cryopreservation method using Cellbanker® 1 could preserve the viability and pathogenesis of K. septempunctata sporoplasm.
Asunto(s)
Criopreservación/métodos , Congelación , Myxozoa/fisiología , Esporas/fisiología , Animales , Células CACO-2 , HumanosRESUMEN
Mycotoxin contamination of crops is a serious problem throughout the world because of its impact on human and animal health as well as economy. Inhibitors of mycotoxin production are useful not only for developing effective methods to prevent mycotoxin contamination, but also for investigating the molecular mechanisms of secondary metabolite production by fungi. We have been searching for mycotoxin production inhibitors among natural products and investigating their modes of action. In this article, we review aflatoxin and trichothecene production inhibitors, including our works on blasticidin S, methyl syringate, cyclo(L-Ala-L-Pro), respiration inhibitors, and precocene II.
Asunto(s)
Aflatoxinas/antagonistas & inhibidores , Aspergillus/efectos de los fármacos , Contaminación de Alimentos/prevención & control , Fungicidas Industriales/farmacología , Fusarium/efectos de los fármacos , Tricotecenos/antagonistas & inhibidores , Aflatoxinas/biosíntesis , Aspergillus/patogenicidad , Aspergillus/fisiología , Benzopiranos/farmacología , Productos Agrícolas/efectos de los fármacos , Productos Agrícolas/microbiología , Fusarium/patogenicidad , Fusarium/fisiología , Ácido Gálico/análogos & derivados , Ácido Gálico/farmacología , Humanos , Nucleósidos/farmacología , Aceites Volátiles/química , Aceites Volátiles/farmacología , Péptidos Cíclicos/farmacología , Enfermedades de las Plantas/microbiología , Relación Estructura-Actividad , Tricotecenos/biosíntesisRESUMEN
To elucidate whether Kudoa septempunctata was able to live in the human intestine, we assessed viability of K. septempunctata sporoplasms under conditions that mimicked human and ragworm digestive tracts. To study the effect of osmotic pressure on viability, sporoplasms were incubated in 0.9 or 3.4 % sodium chloride solutions, which roughly corresponded to the osmotic pressure in human or ragworm tissues, respectively. While viability in 3.4 % sodium chloride did not change after 72 h, it dropped to 21 % in 0.9 % sodium chloride. To study the effect of temperature on viability, sporoplasms were incubated at 37, 15, or 25 °C, which were representative of human, winter ragworm, or summer ragworm temperatures, respectively. Viability decreased sharply to 8.4 % after 48 h at 37 °C, but remained essentially unchanged at 15 and 25 °C. In addition, sporoplasms showed strong susceptibility to bile. These results indicate that K. septempunctata could not live in the human intestine for a long time.
Asunto(s)
Lenguado/parasitología , Enfermedades Intestinales/parasitología , Intestinos/parasitología , Músculos/parasitología , Myxozoa/crecimiento & desarrollo , Animales , Humanos , Myxozoa/aislamiento & purificación , Presión Osmótica/fisiología , Cloruro de Sodio/farmacología , TemperaturaRESUMEN
Enzymes are mainly extracted from the culture broth of microorganisms. Various commercially available enzyme preparations (EPs) are derived from different microorganisms, and the source of the EP should be the same as that mentioned in the manufacture's information. The development of analytical methods that can determine the origin of the final products is important for ensuring that the EPs are nontoxic, especially when used as food additives. In this study, various EPs were subjected to SDS-PAGE, and the main protein bands were excised. After in-gel digestion, the generated peptides were analysed using MALDI-TOF MS, and protein identification was performed by searching the set of peptide masses against protein databases. In total, 36 EPs including amylase, ß-galactosidase, cellulase, hemicellulase and protease were analysed, and the information about the enzyme sources was obtained for 30 EPs. Among these, the biological sources determined for 25 EPs were consistent with the manufacturer's information; for the remaining five, enzymes produced by closely-related species were shown as matching proteins due to high sequence similarity. Six enzymes derived from four microorganisms could not be identified because their protein sequences were not registered in the database. As these databases are expanded, this approach of using SDS-PAGE and peptide mass fingerprinting (PMF) can determine the biological origin of enzymes rapidly and contribute to ensuring the safety of EPs.
Asunto(s)
Péptidos , Proteínas , Péptidos/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Mapeo Peptídico/métodos , Electroforesis en Gel de PoliacrilamidaRESUMEN
Enniatins are emerging mycotoxins that contaminate foods. The present study investigated the oral pharmacokinetics and 28-day repeated-dose oral toxicity of enniatin B (ENNB) in CD1 (ICR) mice. In the pharmacokinetic study, male mice received a single oral or intravenous dose of ENNB [30 mg/kg body weight (BW) and 1 mg/kg BW, respectively]. After oral dosing, ENNB exhibited 139.9% bioavailability, a 5.1-h elimination half-life, 5.26% fecal excretion from 4 to 24 h post-dose, and upregulation of Cyp7a1, Cyp2a12, Cyp2b10, and Cyp26a1 in the liver 2 h post-dosing. In the 28-day toxicity study, ENNB was administered to male and female mice by oral gavage at 0, 7.5, 15, and 30 mg/kg BW/day. Females (7.5 and 30 mg/kg) showed dose-unrelated decreased food consumption without accompanying changes in clinical parameters. Males (30 mg/kg) showed low red blood cell counts and high blood urea nitrogen levels and absolute kidney weights; however, other related parameters including the histopathology of systemic organs/tissues were unchanged. These results suggest that ENNB may not induce toxicity after 28 days of oral administration in mice, despite high absorption. The no-observed-adverse-effect level of ENNB after 28 days of repeated oral doses was 30 mg/kg BW/day for both sexes of mice.
Asunto(s)
Hígado , Ratones , Masculino , Femenino , Animales , Ratones Endogámicos ICR , Nivel sin Efectos Adversos Observados , Administración OralRESUMEN
Small grain cereals are frequently infected with mycotoxigenic Fusarium fungi. Oats have a particularly high risk of contamination with type A trichothecene mycotoxins; their glucoside conjugates have also been reported. Agronomy practices, cereal variety and weather conditions have been suggested to play a role in Fusarium infection in oats. The current study investigates concentrations of free and conjugated Fusarium mycotoxins in organic and conventional oats grown in Scotland. In 2019, 33 milling oat samples (12 organic, 21 conventional) were collected from farmers across Scotland, together with sample questionnaires. Samples were analysed for 12 mycotoxins (type A trichothecenes T-2-toxin, HT-2-toxin, diacetoxyscirpenol; type B trichothecenes deoxynivalenol, nivalenol; zearalenone and their respective glucosides) using LC-MS/MS. The prevalence of type A trichothecenes T-2/HT-2 was very high (100% of conventional oats, 83% of organic oats), whereas type B trichothecenes were less prevalent, and zearalenone was rarely found. T-2-glucoside and deoxynivalenol-glucoside were the most prevalent conjugated mycotoxins (36 and 33%), and co-occurrence between type A and B trichothecenes were frequently observed (66% of samples). Organic oats were contaminated at significantly lower average concentrations than conventional oats, whereas the effect of weather parameters were not statistically significant. Our results clearly indicate that free and conjugated T-2- and HT-2-toxins pose a major risk to Scottish oat production and that organic production and crop rotation offer potential mitigation strategies.
Asunto(s)
Fusarium , Micotoxinas , Toxina T-2 , Tricotecenos Tipo B , Zearalenona , Micotoxinas/análisis , Avena/microbiología , Grano Comestible/química , Zearalenona/análisis , Cromatografía Liquida , Contaminación de Alimentos/análisis , Espectrometría de Masas en Tándem , Toxina T-2/análisis , Escocia , GlucósidosRESUMEN
Co-exposure to aflatoxin and fumonisin is a health concern where corn is a staple food, and a method to prevent co-contamination of these mycotoxins in foods is urgently needed. Polyoxins are chitin synthase inhibitors produced by Streptomyces cacaoi var. asoensis. The aflatoxin production inhibitory activity of a commercially available polyoxin D and four polyoxins purified from polyoxin AL water-soluble powder, an agricultural chemical containing polyoxins, was tested. The five polyoxins dose-dependently inhibited aflatoxin production by Aspergillus parasiticus and the IC50 values of polyoxin A, B, D, K and L were 16, 74, 110, 9 and 280 µmol L-1, respectively. Polyoxins also inhibited fumonisin production by Fusarium fujikuroi, and the IC50 values of polyoxin B, D, K and L were 270, 42, 65 and 62 µmol L-1, respectively. Polyoxins repressed the transcription of genes encoding proteins required for aflatoxin biosynthesis in A. parasiticus and fumonisin biosynthesis in F. fujikuroi. Polyoxin K and D also inhibited conidiation in A. parasiticus and F. fujikuroi, respectively. These results suggest that a mixture of polyoxins may effectively prevent co-contamination of aflatoxin and fumonisin in foods.
Asunto(s)
Aflatoxinas , Fumonisinas , Fusarium , Aspergillus , Fumonisinas/metabolismo , Fusarium/genética , Nucleósidos de PirimidinaRESUMEN
Aerosols or saliva containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can contaminate living environments, and viruses can be indirectly transmitted. To understand the survival potential of the virus, the viral titers of bovine coronavirus (BCoV), as a model virus, and SARS-CoV-2 were measured on porous and non-porous surfaces. The amount of infectious BCoV recovered remained relatively high on non-porous substrates. However, it quickly decreased on several non-porous surfaces such as nitrile rubber. The time taken to reach the limit of detection on non-woven masks, as a porous substrate, was longer than that of non-porous substrates. On porous substrates other than non-woven masks, the amount of virus recovered quickly decreased, and then remained at a low level. Representative substrates were tested with SARS-CoV-2. The decrease in the amount of infectious virus recovered was similar to that of BCoV, although that of SARS-CoV-2 was more rapid. RNA derived from SARS-CoV-2 was also detected using real-time PCR, and it remained on surfaces much longer than infectious virus, on all substrates. Therefore, it is important to measure the viral titer to avoid the overestimation of infectious virus contamination in the environments. Our results suggest that the surface structure was not directly related to viral survivability.
Asunto(s)
COVID-19 , Coronavirus Bovino , Aerosoles , Humanos , Máscaras , SARS-CoV-2RESUMEN
Fusarium head blight (FHB) caused by pathogenic species of Fusarium fungi is one of the most important diseases of cereal plants and a factor contributing to losses in plant production. The growth of FHB-associated species is often accompanied by biosynthesis of secondary metabolitesâmycotoxins, which serve as a virulence factor. The aim of the study was to evaluate the ratios between deoxynivalenol (DON) and nivalenol (NIV) and their derivatives in the ears of six cultivars of winter wheat with varying resistance to FHB, taking into account a range of factors (weather conditions, location, cultivar, and year) after inoculation with Fusarium culmorum, during a 3 year field experiment, 2018-2020. The presence of toxins in the ears was measured within 21 days of inoculation. The toxins were found in the ears as soon as on the third day from the start of the experiment, whereas relative humidity higher than 80% was a decisive factor for FHB incidence. All wheat cultivars showed the ability to biotransform DON and NIV present in the ears to glucosides, that is, deoxynivalenol-3-glucoside (DON-3G) and nivalenol-3-glucoside (NIV-3G). The levels of these metabolites showed significant correlation with the levels of their basic analogues. In most cases, higher levels of DON and NIV in wheat ears and higher levels of their metabolites were observed, but the relative levels of DON-3G/DON and NIV-3G/NIV at relatively high levels of toxins were lower compared to the ear samples with relatively low toxin levels. The presented results are the first studies, which systematically correlate a variety of wheat cultivars with their extent to glucosylate trichothecenes.
Asunto(s)
Fusarium , Micotoxinas , Tricotecenos , Fusarium/metabolismo , Glucósidos/metabolismo , Micotoxinas/metabolismo , Enfermedades de las Plantas/microbiología , Tricotecenos/metabolismo , Triticum/metabolismoRESUMEN
This study investigated the impact of malting of six wheat cultivars inoculated with Fusarium culmorum on the dynamics of content changes of selected Fusarium toxins. The grains of all the tested cultivars showed a high content of deoxynivalenol (DON), zearalenone (ZEN), and their derivatives, whereas nivalenol (NIV) and its glucoside were found only in the Legenda cultivar. Our experiments confirmed that the malting process of wheat grain enables the secondary growth of Fusarium, and mycotoxin biosynthesis. The levels of toxins in malt were few-fold higher than those in grain; an especially high increase was noted in the case of ZEN and its sulfate as the optimal temperature and pH conditions for the biosynthesis of these toxins by the pathogen are similar to those used in the grain malting process. This is the first paper reporting that during the malting process, biosynthesis of ZEN sulfate occurs, instead of glycosylation, which is a typical modification of mycotoxins by plant detoxication enzymes.