Serodiversity, antibiotic resistance, and virulence genes of Vibrio parahaemolyticus in oysters collected in coastal areas of northwestern Mexico between 2012 and 2020.

This study aimed to determine the prevalence of V. parahaemolyticus in oysters from the northwestern coast of Mexico and to identify the serotypes, virulence factors, and antibiotic resistance of the strains. Oyster samples were collected from 2012 to 2020 from the northwest coast of Mexico; biochemical and molecular methods were used to identify V. parahaemolyticus from oysters; antiserum reaction to determine V. parahaemolyticus serotypes, and PCR assays were performed to identify pathogenic (tdh and/or trh) or pandemic (toxRS/new, and/or orf8) strains and antibiotic resistance testing. A total of 441 oyster samples were collected and tested for V. parahaemolyticus. Forty-seven percent of oyster samples were positive for V. parahaemolyticus. Ten different O serogroups and 72 serovars were identified, predominantly serotype O1:KUT with 22.2% and OUT:KUT with 17.3%. Twenty new serotypes that had not been previously reported in our region were identified. We detected 4.3% of pathogenic clones but no pandemic strains. About 73.5% of strains were resistant to at least one antibiotic, mainly ampicillin and ciprofloxacin; 25% were multi-drug resistant. In conclusion, the pathogenic strains in oysters and antibiotic resistance are of public health concern, as the potential for outbreaks throughout northwestern Mexico is well established.

Tamoxifen induces biochemical responses in Pacific oysters Magallana gigas (Thunberg, 1793) at environmentally relevant concentrations.

The activities of catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), and glutathione-S-transferase (GST) were evaluated in the gills (GI) and digestive gland (DG) of Magallana gigas oysters exposed to tamoxifen (TAM) at environmental concentrations of 10 and 100 ng L-1 for 1 and 4 days. A higher CAT activity in the GI and DG and higher GPx activity only in the DG was observed of oysters exposed to both concentrations after 1 day. Furthermore, a significant increase in GR and G6PDH, was detected in the DG after 1 day of exposure to 10 ng L-1 and only G6PDH activity increase after 1 day of exposure to 10 ng L-1 in the GI. This suggests that the DG is a tissue more sensitive to TAM exposure and was confirmed with the individual Integrated Biomarker Response version 2 index (IBRv2i), highlighting the acute stress caused by TAM and a cellular adaptation.

Assessment of coastal pollutants and health status of Pacific oysters (Magallana gigas) in the Bahía Blanca Estuary and adjacent beaches (Argentina).

This study assessed the effects of pollutants on Magallana gigas along a coastal zone with different levels of human activity: a highly impacted zone in the Bahía Blanca Estuary and a less impacted zone on the adjacent sandy beaches. Oysters collected in 2021 were analyzed for various factors, including metals, polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, microplastics, oxidative stress and histology. Oysters of both environments exhibited detectable concentrations of all these pollutants in their tissues. However, the estuarine oysters showed higher concentrations of Zn, Cu and As and total PAHs than the beach oysters. Banned organochlorine pesticides were detected only in beach oysters. Estuarine oysters displayed morphological changes in their digestive gland including a reduction in the mean epithelial thickness of the tubule and elevated lipid peroxidation levels, indicating cellular damage. This study underscores the widespread presence of pollutants in M. gigas, indicating the need for effective strategies to safeguard coastal ecosystem health.

Assessment of Gastroenteric Viruses in Marketed Bivalve Mollusks in the Tourist Cities of Rio de Janeiro, Brazil, 2022.

This study investigated the prevalence and genetic diversity of gastroenteric viruses in mussels and oysters in Rio de Janeiro, Brazil. One hundred and thirty-four marketed bivalve samples were obtained between January and December 2022. The viral analysis was performed according to ISO/TS 15216, and the screening revealed the detection of norovirus GII/GI (40.3%), sapovirus (SaV; 12.7%), human mastadenovirus (7.5%), and rotavirus A (RVA; 5.9%). In total, 44.8% (60) of shellfish samples tested positive for one or more viruses, 46.7% (28/60) of the positive samples tested positive for a single viral agent, 26.7% (16) tested positive for two viral agents, 8.3% (5) for three viral agents, and 13.3% (8) for four viral agents. Additionally, three mussel samples were contaminated with the five investigated viruses (5%, 3/60). Norovirus GII showed the highest mean viral load (3.4 × 105 GC/g), followed by SaV (1.4 × 104 GC/g), RVA (1.1 × 104 GC/g), human mastadenovirus (3.9 × 103 GC/g), and norovirus GI (6.7 × 102 GC/g). Molecular characterization revealed that the recovered norovirus strains belonged to genotypes GII.2, GII.6, GII.9, GII.17, and GII.27; SaV belonged to genotypes GI.1 and GIV.1; RVA to genotypes G6, G8, P[8]-III, and human mastadenovirus to types F40 and F41. The GII.27 norovirus characterized in this study is the only strain of this genotype reported in Brazil. This study highlights the dissemination and diversity of gastroenteric viruses present in commercialized bivalves in a touristic area, indicating the potential risk to human health and the contribution of bivalves in the propagation of emerging pathogens.

Integrated analysis of marine biotoxins and contaminants of emerging concern in bivalve mollusks from Santa Catarina, Brazil.

Santa Catarina is the main producer state of oysters and mussels in Brazil, reaching 98 % of national production. To assure the safety of bivalve mollusks production, control programs of marine biotoxins (MBs) have been continuously performed. Herein, the co-occurrence of MBs and contaminants of emerging concern (CECs) in oyster and mussels from the main production sites of Santa Catarina was reported, covering 178 compounds. Samples of wild and non-cultivated oysters and mussels were also assessed. Chemometric tools were used to evaluate and optimize several sample preparation techniques such as solid-liquid, ultrasound assisted, and pressurized liquid extraction. The optimized protocol was based on ultrasound assisted extraction followed by liquid chromatography coupled to tandem mass spectrometry. The results showed the incidence of several CECs and MBs. In the case of MBs, all results were below the regulatory limits for both cultivated and non-cultivated samples. Wild mollusks have shown a higher number of compounds. Regarding CECs, the more frequent compounds were caffeine, diclofenac, meloxicam, and sertraline. Domoic acid and okadaic acid were the main toxins detected. The results highlighted the need of monitoring for MBs and the potential of oyster and mussels as sentinel organisms to risk analysis of CECs in coastal regions. To the best of our knowledge, this is the first method to describe a simultaneous sample preparation and analysis of CECs and MBs in bivalve mollusks, as well as the first report of meloxicam and florfenicol in mussels and oysters.

Cryptosporidium sp. in cultivated oysters and the natural oyster stock of the state of Maranhão, Brazil / Detecção de Cryptosporidium sp. em ostras de cultivo e estoque natural no estado do Maranhão, Brasil

This study detected Cryptosporidium spp. in cultivated oysters and the natural oyster stock of the state of Maranhão and determine the elective tissue(s) to examine this protozoan. For this purpose, 200 cultivated oysters were purchased from the municipality of Raposa and another 100 from Paço do Lumiar. Additionally, 100 oysters were extracted from the natural stock of the municipality of Primeira Cruz, thus making up a total of 400 oysters. They were grouped into 80 pools consisting of 5 oysters each. From each pool, the gills and visceral mass were removed to obtain 160 pools, 80 pools for the gill group and another 80 for the visceral mass group. Then, DNA was extracted from each pool using a commercial kit with modifications. Subsequently, the protozoan DNA was detected using nested polymerase chain reaction. With this technique, the DNA of the protozoan under investigation was detected in 2.5% (n = 2/80) of the pools containing gills, with 1.25% of the pools (n = 1/80) belonging to the cultivation group of oysters and the other 1.25% (n = 1/80) to the natural stock. With the results obtained in this study, it was concluded that the analyzed oysters of the genus Crassostrea, from cultivation and natural stock groups, found in the state of Maranhão, were contaminated by Cryptosporidium spp. and may become potential sources of infection in humans and other animals. In addition, the gills are the elective tissue for the study of Cryptosporidium spp. in oysters.

Objetivou-se com o estudo detectar Cryptosporidium sp. em ostras de cultivo e estoque natural no estado do Maranhão e determinar o(s) tecido(s) eletivo(s) para pesquisa desse protozoário. Para a realização do estudo foram adquiridas 200 ostras de cultivo do município de Raposa e 100 de Paço do Lumiar, além de 100 ostras extraídas de estoque natural do município de Primeira Cruz, totalizando 400 ostras. Estas foram agrupadas em 80 pools constituídos por cinco animais. De cada pool, as brânquias e a massa visceral foram removidas totalizando 160 pools, sendo 80 para o grupo das brânquias e 80 para o grupo de massa visceral. Na sequência, procedeu-se à extração de DNA de cada pool com a utilização de kit comercial com modificações. Posteriormente, realizou-se a detecção do DNA do protozoário por meio da técnica de Nested-PCR. Com a técnica utilizada, foi detectado o DNA do protozoário pesquisado em 2,5% (n=2/80) pools apenas de brânquias, sendo 1,25% pools (n=1/80) oriundos de cultivo e os outros 1,25% (n=1/80) de estoque natural. Com os resultados obtidos nesse estudo, conclui-se que as ostras analisadas do gênero Crassostrea sp., oriundas de cultivo e estoque natural no estado do Maranhão, estavam contaminadas por Cryptosporidium sp. e podem se reverter em fontes potenciais para seres humanos e outros animais. Para a pesquisa de Cryptosporidium sp. em ostras, as brânquias são o tecido eletivo.

Evaluation of Paralytic Shellfish Toxins in Marine Oyster Farming and Microalgae in the Atlantic Amazon Evidences Safety but Highlights Potential Risks of Shellfish Poisoning.

Marine phycotoxins are organic compounds synthesized by some species of microalgae, which accumulate in the tissues of filter-feeder organisms such as bivalve mollusks. These toxins can cause acute intoxication episodes in humans, a severe threat to aquaculture and fisheries. In the State of Pará, Brazil, oyster farming has community, artisanal and sustainable bases, using mangroves as cultivation environment and seed banks. In small-scale production, there are often no established methods of safeguarding the health of consumers elevating the potential risks of shellfish poisoning outbreaks. Our study evaluated the presence of phycotoxins in oysters cultivated in five municipalities in the region of the Atlantic Amazon (Pará, Brazil) assessing the quality of the final product. We further evaluated the microalgae, water quality, and the spatio-temporal variation of physicochemical factors in the same area. Diatoms dominated the microalgae composition, followed by dinoflagellates, some of which are reported to be potentially toxic and producers of paralytic shellfish toxins. For the first time, we describe the occurrence of the potentially toxic dinoflagellate Ostreopsis sp. in the Amazon region. Furthermore, for the first time, toxins were detected in oyster farming in the northeast of the State of Pará, namely GTX2,3, STX, and dc-STX nevertheless, with nontoxic values. The identified toxins represent a potential threat to shellfish consumers.

Dietary Supplementation with Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), Reduces Visceral Fat and Hyperlipidemia in Inhabitants of a Rural Community in Mexico.

The abandonment of traditional foods in the Mexican diet is one of the causes for the increase in diseases associated with obesity. Edible mushrooms have been a part of the Mexican diet since pre-Hispanic times. There is clear evidence that Pleurotus ostreatus (Po) contains bioactive compounds that have beneficial health effects. In the present study, we carried out a 3-month nutritional intervention in which we randomized 30 participants into two groups: one that consumed a healthy diet with regional foods without the inclusion of edible mushrooms (HD, n = 15) and one that consumed a healthy diet with regional foods alongside 1 kg of P. ostreatus (four portions of 250 g) per week (HD+ P. ostreatus, n = 15). We evaluated anthropometric measurements, lipid parameters, glucose levels, and blood pressure in inhabitants of San Miguel Tianguistenco, Puebla, a rural area of Mexico. For the HD group, the triglyceride levels decreased in women and the glucose levels decreased in men, and in the HD+ P. ostreatus group, visceral fat, glucose, triglyceride, and cholesterol levels decreased in women, and glucose and triglyceride levels decreased in men. Analysis of the intake of macro- and micronutrients in the community showed a high intake of energy, fat, and sugar, and a low intake of fiber, B complex vitamins, and minerals, indicators of an unbalanced diet. It is essential to create strategies that promote the inclusion of edible mushrooms as a part of a heathy diet in rural areas of Mexico to improve the actual health and nutrition of the residents.

Norovirus GII and astrovirus in shellfish from a mangrove region in Cananéia, Brazil: molecular detection and characterization.

In recent years, annual cases of gastroenteritis have been reported in the world at high rates, suggesting an association with the consumption of shellfish with enteric viruses in their tissues. Anthropic activities are considered a source of environmental pollution and the main responsible for contamination by pathogenic microorganisms in aquatic environments. The objective of this study was to evaluate, by RT-semi-nested PCR, the presence of astrovirus (AstV) and norovirus genogroup II (NoV GII) in mussels (Mytella falcata) and oysters (Crassostrea brasiliana) collected in two sites of the Lagunar Complex of Cananéia, State of São Paulo, Brazil. A total of 150 samples of mussels and oysters (75 samples each) were analyzed. AstV was not identified in any shellfish sample. NoV GII was detected in 21 samples (14%), 8 mussel samples (38%), and 13 oyster samples (62%). From the 21 positive samples, 16 were analyzed by nucleotide sequencing. The molecular characterization revealed that Brazilian samples were grouped into clades along with other sequences from Brazil, Japan, and Mexico. There was 93.8-100% amino acid sequence similarity among the samples in this study and > 94.9% when compared with the strains isolated from clinical cases in Brazil. The screening of shellfish for the presence of health-significant enteric viruses can help prevent outbreaks among consumers and contribute to the improvement of the estuarine environment.

Monitoring metallothionein-like protein concentrations and cholinesterase activity in tropical cup oysters as biomarkers of exposure to metals and pesticides in the southern Caribbean, Colombia.

Metallothionein-like protein concentrations (MT) and three functionally defined fractions of cholinesterase activity (ChE) were quantified in gill and digestive gland homogenates of tropical cup oysters from 5 nearshore locations in the Colombian Caribbean and correlated with sediment and tissue metal (9 metals) and pesticide (22 organophosphates, OPs, and 20 organochlorines-OCPs), as well as water physical-chemical parameters (salinity, pH, temperature, and dissolved oxygen). Tissue and sediment pesticide concentrations were below detection limits in all samples, whereas sediment and tissue metal concentrations exceeded environmental thresholds at several locations. Tissue MT and ChE biomarkers varied by a factor of 5-6 between locations. Inhibition of cholinesterase activity was negligible for all 5 sites, despite spatial-temporal variation in ChE activity, consistent with below-detection OP concentrations. Tissue MT and ChE biomarkers correlated with tissue and metal sediment concentrations, yet, statistically significant covariance between biomarkers and water chemistry parameters was also observed, indicating that both, metal concentrations and physical-chemical variables, are likely to be responsible for generating the observed spatial-temporal variations in biomarker patterns.

Biological control of incrusting organisms and sediments in Chilean oyster cultures / Controle biológico dos organismos incrustáveis e sedimentos em culturas de ostras Chilenas

The oyster culture has the incrusting organism as problem for production, in this context, it evaluated as biological control against incrusting organism and sediments the introduction of gastropod Tegula atra (Lesson, 1830) in Chilean oysters (Triostrea chilensis Phillippi, 1844) cultures in conditions of starvation presence and absence located in floating cages and bottom cultures. The predation and mechanic effect on T. atra grazing generated a decreasing in seven days of 19.8% and 13.7% of incrusting organisms in cage culture and bottom sediments by effects of gastropods without starvation respectively. Whereas it had a decrease of 12.6% and 11.4% of incrusting organisms in cage culture and bottom sediments by effects of gastropods with starvation respectively. The incrusting organism removed were mainly algae, colonial ascidia, polychaeta, bryozoan and small crustaceans.(AU)

A cultura da ostra tem como problema de produção o organismo incrustante, neste contexto, avaliou como controle biológico contra organismos incrustantes e sedimentos a introdução do gastrópode Tegula atra (Lesson, 1830) em culturas de ostras chilenas (Triostrea chilensis Phillippi, 1844) em condições de presença e ausência de fome, localizadas em gaiolas flutuantes e culturas de fundo. A predação e o efeito mecânico no pastejo de T. atra geraram uma diminuição em sete dias de 19,8% e 13,7% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo, por efeito de gastrópodes sem fome, respectivamente. Considerando que houve decréscimo de 12,6% e 11,4% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo pelos efeitos dos gastrópodes com fome respectivamente. Os organismos incrustantes removidos eram principalmente algas, ascídias coloniais, poliquetas, briozoários e pequenos crustáceos.(AU)

Particle size of oyster shell meal and calcium: phosphorus ratios in broiler diets / Efeito do tamanho de partícula da farinha de ostras e relações cálcio: fósforo em dietas para frangos de corte

The effects of Ca:P total ratio and particle size of oyster shell meal (OSM) were evaluated in broiler diets. In Experiment 1, 800 broilers (22-42 days old) were distributed in a 2×2 factorial design, with two Ca:P ratios (1.7 and 2.0:1) and two OSM particle sizes (coarse = 1,354 µm and fine = 428 µm), totaling four treatments with 10 repetitions with 20 broilers. Feed intake, weight gain, and feed conversion ratio were calculated. In Experiment 2, 1,280 broilers were distributed in a 2×2×2 factorial design (1.7 and 2.0:1 Ca:P ratios; coarse and fine OSM; male and female broilers), with eight treatments and 16 repetitions with 10 broilers. Apparent metabolizability of dry matter, Ca, P, and apparent metabolizable energy (AME), as well as bone resistance, bone weight, ash, Ca, and P content in the tibia were assessed. Growth performance was not affected (P > 0.05). Coarse OSM increased tibia Ca content in male broilers (P < 0.001), and higher Ca:P ratio improved bone ash and bone resistance in both sexes (P < 0.001), but reduced P content in male broilers (P < 0.05); male broilers displayed heavier bones with higher ash content than females (P < 0.05). Metabolizability of Ca was improved with coarse OSM (P < 0.05); whereas metabolizability of DM, P, and AME was not affected (P > 0.05). In conclusion, diets with a Ca:P total ratio of 2.0:1 containing coarser OSM improved bone mineral composition, particularly in male broilers, and coarse OSM improved the metabolizability of Ca in broilers regardless of the Ca:P total ratio or broiler sex.

Dois experimentos foram conduzidos para avaliar os efeitos do tamanho de partícula da farinha de ostras (FO) e relação Ca:P total em dietas para frangos de corte. No primeiro experimento, 800 frangos (22 a 42 dias) foram distribuídos em um delineamento fatorial 2x2: 2 relações Ca:P (1,7 e 2,0:1) e dois tamanhos de partícula da FO (grossa = 1354 µm e fina = 428 µm), totalizando quatro tratamentos com 10 repetições de 20 aves. O consumo de ração, o ganho de peso e a conversão alimentar foram calculados. No segundo experimento, 1.280 frangos foram distribuídos em um fatorial 2x2x2 (relações Ca:P 1,7 e 2,0:1; FO grossa e fina; aves machos e fêmeas) com oito tratamentos e 16 repetições de 10 aves. Foram avaliados: metabolizabilidade aparente da matéria seca, Ca e P, energia metabolizável aparente (EMA), peso e resistência óssea, conteúdo de cinzas, Ca e P na tíbia. As variáveis de desempenho não foram afetadas (P > 0,05). O uso de FO grossa aumentou o conteúdo de Ca na tíbia de frangos machos (P < 0,001), e a relação Ca:P de 2,0:1 aumentou o conteúdo de cinzas e aprimorou resistência óssea em ambos os sexos (P < 0,001), porém reduziu P na tíbia dos machos (P < 0,05); frangos machos também tiveram ossos mais pesados e maior conteúdo de cinzas do que fêmeas (P < 0,05). A metabolizabilidade de Ca foi melhorada com FO grossa, enquanto a metabolizabilidade da matéria seca, P, e EMA não foram afetadas (P > 0,05). Conclui-se que as dietas com relação Ca:P de 2,0:1 e com FO grossa resultaram em melhor composição mineral óssea - particularmente em frangos machos - e a FO grossa melhorou a metabolizabilidade de Ca independentemente da relação Ca:P ou do gênero das aves.

Biological control of incrusting organisms and sediments in Chilean oyster cultures / Controle biológico dos organismos incrustáveis e sedimentos em culturas de ostras Chilenas

The oyster culture has the incrusting organism as problem for production, in this context, it evaluated as biological control against incrusting organism and sediments the introduction of gastropod Tegula atra (Lesson, 1830) in Chilean oysters (Triostrea chilensis Phillippi, 1844) cultures in conditions of starvation presence and absence located in floating cages and bottom cultures. The predation and mechanic effect on T. atra grazing generated a decreasing in seven days of 19.8% and 13.7% of incrusting organisms in cage culture and bottom sediments by effects of gastropods without starvation respectively. Whereas it had a decrease of 12.6% and 11.4% of incrusting organisms in cage culture and bottom sediments by effects of gastropods with starvation respectively. The incrusting organism removed were mainly algae, colonial ascidia, polychaeta, bryozoan and small crustaceans.

A cultura da ostra tem como problema de produção o organismo incrustante, neste contexto, avaliou como controle biológico contra organismos incrustantes e sedimentos a introdução do gastrópode Tegula atra (Lesson, 1830) em culturas de ostras chilenas (Triostrea chilensis Phillippi, 1844) em condições de presença e ausência de fome, localizadas em gaiolas flutuantes e culturas de fundo. A predação e o efeito mecânico no pastejo de T. atra geraram uma diminuição em sete dias de 19,8% e 13,7% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo, por efeito de gastrópodes sem fome, respectivamente. Considerando que houve decréscimo de 12,6% e 11,4% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo pelos efeitos dos gastrópodes com fome respectivamente. Os organismos incrustantes removidos eram principalmente algas, ascídias coloniais, poliquetas, briozoários e pequenos crustáceos.

Biological control of incrusting organisms and sediments in Chilean oyster cultures / Controle biológico dos organismos incrustáveis e sedimentos em culturas de ostras Chilenas

The oyster culture has the incrusting organism as problem for production, in this context, it evaluated as biological control against incrusting organism and sediments the introduction of gastropod Tegula atra (Lesson, 1830) in Chilean oysters (Triostrea chilensis Phillippi, 1844) cultures in conditions of starvation presence and absence located in floating cages and bottom cultures. The predation and mechanic effect on T. atra grazing generated a decreasing in seven days of 19.8% and 13.7% of incrusting organisms in cage culture and bottom sediments by effects of gastropods without starvation respectively. Whereas it had a decrease of 12.6% and 11.4% of incrusting organisms in cage culture and bottom sediments by effects of gastropods with starvation respectively. The incrusting organism removed were mainly algae, colonial ascidia, polychaeta, bryozoan and small crustaceans.

A cultura da ostra tem como problema de produção o organismo incrustante, neste contexto, avaliou como controle biológico contra organismos incrustantes e sedimentos a introdução do gastrópode Tegula atra (Lesson, 1830) em culturas de ostras chilenas (Triostrea chilensis Phillippi, 1844) em condições de presença e ausência de fome, localizadas em gaiolas flutuantes e culturas de fundo. A predação e o efeito mecânico no pastejo de T. atra geraram uma diminuição em sete dias de 19,8% e 13,7% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo, por efeito de gastrópodes sem fome, respectivamente. Considerando que houve decréscimo de 12,6% e 11,4% dos organismos incrustantes na cultura em gaiola e nos sedimentos de fundo pelos efeitos dos gastrópodes com fome respectivamente. Os organismos incrustantes removidos eram principalmente algas, ascídias coloniais, poliquetas, briozoários e pequenos crustáceos.

Production and Nutritional Composition of King Oyster Culinary-Medicinal Mushroom Pleurotus eryngii (Agaricomycetes) Biomass from Brazil.

The present study aimed to evaluate the nutritional composition and production of mycelial biomass of Pleurotus eryngii in different culture media, formulated with infusion of purple-skinned sweet potato, glucose concentrations, and the presence or absence of yeast extract. The mushroom was grown for 15 days at 25°C and 150 rpm. The best production of mycelial biomass occurred in the culture medium with 40 g/L of glucose plus yeast extract. At the second cultivation, the fungus entered the exponential growth phase from days 6 until 14. These results indicate that the insertion of nutritional sources in purple-skinned sweet potato media positively influences mycelial biomass production and its nutritional characteristics make it useful for food industry applications.

Elevated seasonal temperature disrupts prooxidant-antioxidant homeostasis and promotes cellular apoptosis in the American oyster, Crassostrea virginica, in the Gulf of Mexico: a field study.

One of the major impacts of climate change has been the marked rise in global temperature. Recently, we demonstrated that high temperatures (1-week exposure) disrupt prooxidant-antioxidant homeostasis and promote cellular apoptosis in the American oyster. In this study, we evaluated the effects of seasonal sea surface temperature (SST) on tissue morphology, extrapallial fluid (EPF) conditions, heat shock protein-70 (HSP70), dinitrophenyl protein (DNP, an indicator of reactive oxygen species, ROS), 3-nitrotyrosine protein (NTP, an indicator of RNS), catalase (CAT), superoxide dismutase (SOD) protein expressions, and cellular apoptosis in gills and digestive glands of oysters collected on the southern Texas coast during the winter (15 °C), spring (24 °C), summer (30 °C), and fall (27 °C). Histological observations of both tissues showed a notable increase in mucus production and an enlargement of the digestive gland lumen with seasonal temperature rise, whereas biochemical analyses exhibited a significant decrease in EPF pH and protein concentration. Immunohistochemical analyses showed higher expression of HSP70 along with the expression of DNP and NTP in oyster tissues during summer. Intriguingly, CAT and SOD protein expressions exhibited significant upregulation with rising seasonal temperatures (15 to 27 °C), which decreased significantly in summer (30 °C), leaving oysters vulnerable to oxidative and nitrative damage. qRT-PCR analysis revealed a significant increase in HSP70 mRNA levels in oyster tissues during the warmer seasons. In situ TUNNEL assay showed a significant increase in apoptotic cells in seasons with high temperature. These results suggest that elevated SST induces oxidative/nitrative stress through the overproduction of ROS/RNS and disrupts the antioxidant system which promotes cellular apoptosis in oysters.

Microplastic concentrations in cultured oysters in two seasons from two bays of Baja California, Mexico.

As filter feeders, bivalve mollusks have a high potential risk of contamination by microplastics (MPs), which can be considered a transfer vector for humans through their consumption. Spatial-temporal differences in the MP concentration were evaluated in the cultured oyster Magallana gigas in Todos Santos Bay (TSB) and San Quintin Bay (SQB) during winter and summer (2019). MPs were found in all samples in both seasons, where microfibers were the most abundant particles observed. Only in winter, statistically significant differences were observed in the average concentration of ingested MPs between oysters from TSB and SQB. In each bay, the highest concentrations were observed during winter. Seasonal differences between MP concentrations were only found in TSB. During summer, the content of MPs was compared between the digestive system and the rest of the soft tissue in organisms from each site, and statistically significant differences were not observed, except by one site in SQB. Polymers were identified via µ-FTIR-ATR spectrometry. Polyester, polyacrylonitrile, and rayon were the most common plastics detected. However, due to the low concentration of MPs found in oysters, its consumption does not represent a risk to human health. Moreover, MP concentrations in organisms appear to respond to variables, such as temporality and the water circulation dynamics within the bays.

Effects of Farm Location on Vibrio parahaemolyticus and Vibrio vulnificus Levels in Oysters after Desiccation and Resubmersion in the Northern Gulf of Mexico.

ABSTRACT: Desiccation is a routine farming practice used in off-bottom oyster aquaculture to reduce biofouling organisms and improve shell quality. This practice can increase Vibrio parahaemolyticus and Vibrio vulnificus levels, leading to increased risk of illness for raw oyster consumers. Previous resubmersion studies were performed in geographic proximity to one another, so to better understand the broader applicability of resubmersion, the next step was to perform concurrent studies in multiple geographic locations within a region. This study evaluated the effect of variations in geographic location on the recovery time needed for elevated vibrio levels to return to ambient levels in desiccated oysters after resubmersion at Gulf Coast farms. Two trials were performed between May and August 2019 at sites spanning ∼100 km: three in Alabama and one in Florida. Oysters were deployed in OysterGro cages at each location, 2 weeks before each trial, and then either were desiccated for 24 h or remained submersed as controls. Triplicate samples were taken before and immediately following the desiccation period, as well as 7 and 14 days after resubmersion. Total and pathogenic V. parahaemolyticus and V. vulnificus levels were determined using most-probable-number (MPN) real-time PCR. Vibrio levels increased by 0.23 to 3.50 log MPN/g after desiccation. Recovery times varied among geographic locations by trial and Vibrio spp., with all vibrio counts recovering to levels not significantly higher than those in control oysters within 7 to 14 days of resubmersion (P ≥ 0.06). These results suggest a 14-day resubmersion period of cultured oysters allowed vibrio levels, elevated because of routine handling, to return to ambient levels at all farm sites studied.

Nutritional and Bioactive Properties of an Amazon Wild Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes): Contributions to Functional Food and Human Health.

A wild Amazonian strain of Pleurotus ostreatus (Jacq.: Fr.) P. Kumm. was cultivated using local agroindustrial wastes-açai seeds (AS) and elephant grass straw (EGS)-as substrates and evaluated for its nutritional composition and bioactivities. Basidiomata presented higher contents of protein (27.19%) and dietary fiber (18.57%) when grown on AS, while lipids (2.26%), nonfiber carbohydrates (53.21%), and metabolizable energy (304.02 kcal/100 g) were higher on EGS substrate. Methanolic extracts of P. ostreatus grown on AS also provided a higher phenolic content (31.24 mg gallic acid equivalents/g extract) and greater antioxidant activity, scavenging 82.60% and 91.13% of DPPH· and ABTS·+ radicals, respectively, while chelating ability of Fe2+ was higher on EGS mushroom extracts (74.34%). Hemagglutinating activity of 1,997 HA U/mg protein was observed solely in the aqueous extracts of AS-grown mushrooms. Higher proteolytic activity was observed in aqueous extracts from mushrooms grown on EGS (219.10 U/mg protein), and their saline extract was the sole one with fibrinolytic activity (3.14 mm2). Both substrates and extractions yielded similar activity of protease inhibitors, with higher inhibition of serine than cysteine proteases. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis profiling showed protein bands related to lectins, proteases, fibrinolytic enzymes, and protease inhibitors. Thus, this wild Amazonian strain has great nutritional potential and produces biomolecules that can contribute to important applications in food, health, and industry.

Assessment of Microbiological Quality of Fresh Vegetables and Oysters Produced in Buenos Aires Province, Argentina.

Fresh vegetables and shellfish are prone to microbial contamination through irrigation or breeding with sewage-polluted waters, as well as by infected food handlers. In this work, we studied the presence of human and bovine polyomaviruses and human norovirus in fresh lettuces, strawberries and oysters produced in Buenos Aires province, Argentina. In oysters, we also investigated F-specific RNA bacteriophages, indicator Escherichia coli (E. coli) and pathogen bacteria of concern (Salmonella spp., Vibrio spp.). Within vegetables, we found viral contamination of human origin given the presence of human-associated polyomaviruses -MCPyV, HPyV6, JCPyV, and SV40- in lettuce and strawberry samples (16 and 10%, respectively), probably coming from irrigation waters and food handling. Among oysters, human (MCPyV, 4.2%) and bovine (BPyV1, 8.4%) polyomaviruses were detected even with low counts of E. coli. Bacteriophages (n = 3) and Salmonella spp. (n = 1) were also found, while Vibrio spp. was not detected. These results may indicate that the contamination in oysters comes from human and animal excreta, probably present in breeding waters. Norovirus was not detected in any food sample. To our knowledge, this is the first description of SV40 in lettuces and MCPyV and BPyV1 in oysters. The detection of different viral contaminants encourages further studies to evaluate the need for including viral indicators in microbiological standards. The identification of possible sources and routes of contamination using viral markers during routine microbiological controls, such as the polyomaviruses used in this work, would be useful to focus attention on the most hazardous stages of the food production chain.