Polyunsaturated fatty acids are important nutrients for human health, especially omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have been found to play positive roles in the prevention of various diseases. However, previous studies have reported that excessive omega-3 fatty acids supplement during pregnancy caused side effects such as slower neural transmission times and postnatal growth restriction. In this study, we investigated the effect of EPA and DHA on mitochondrial function and gene expression in C2C12 myoblasts during skeletal muscle differentiation. C2C12 myoblasts were cultured to confluency and then treated with differentiation medium that contained fatty acids (50-µM EPA and DHA). After 72 h of myogenic differentiation, mRNA was collected, and gene expression was analyzed by real-time PCR. Microscopy was used to examine cell morphology following treatment with fatty acids. The effect of EPA and DHA on cellular oxygen consumption was measured using a Seahorse XF24 Analyzer. Cells treated with fatty acids had fewer myotubes formed (P ≤ 0.05) compared with control cells. The expression of the genes related to myogenesis was significantly lower (P ≤ 0.05) in cells treated with fatty acids, compared with control cells. Genes associated with adipogenesis had higher (P ≤ 0.05) expression after treatment with fatty acids. Also, the mitochondrial biogenesis decreased with lower (P ≤ 0.05) gene expression and lower (P ≤ 0.05) mtDNA/nDNA ratio in cells treated with fatty acids compared with control cells. However, the expression of genes related to peroxisome biosynthesis was higher (P ≤ 0.05) in cells treated with fatty acids. Moreover, fatty-acid treatment reduced (P ≤ 0.05) oxygen consumption rate under oligomycin-inhibited (reflecting proton leak) and uncoupled conditions. Our data imply that fatty acids might reduce myogenesis and increase adipogenesis in myotube formation. Fatty acids may also decrease cell metabolism by reducing mitochondrial biogenesis as well as respiration rate. This study suggests that the maternal overdosage of EPA and DHA may influence fetal muscle development, increase intramuscular adipose tissue deposition in offspring, and have a long-term effect on the development of metabolic diseases such as obesity and diabetes in adult offspring.

Human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks, as well as virus-related waterborne disease outbreaks in the United States. Here, we hypothesize that common free-living amoebae (FLA)-ubiquitous in the environment, known to interact with pathogens, and frequently isolated from water and fresh produce-could potentially act as reservoirs of HuNoV and facilitate the environmental transmission of HuNoVs. To investigate FLA as reservoirs for HuNoV, the interactions between two Acanthamoeba species, A. castellanii and A. polyphaga, as well as two HuNoV surrogates, murine norovirus type 1 (MNV-1) and feline calicivirus (FCV), were evaluated. The results showed that after 1 h of amoeba-virus incubation at 25°C, 490 and 337 PFU of MNV-1/ml were recovered from A. castellanii and A. polyphaga, respectively, while only few or no FCVs were detected. In addition, prolonged interaction of MNV-1 with amoebae was investigated for a period of 8 days, and MNV-1 was demonstrated to remain stable at around 200 PFU/ml from day 2 to day 8 after virus inoculation in A. castellanii. Moreover, after a complete amoeba life cycle (i.e., encystment and excystment), infectious viruses could still be detected. To determine the location of virus associated with amoebae, immunofluorescence experiments were performed and showed MNV-1 transitioning from the amoeba surface to inside the amoeba over a 24-h period. These results are significant to the understanding of how HuNoVs may interact with other microorganisms in the environment in order to aid in its persistence and survival, as well as potential transmission in water and to vulnerable food products such as fresh produce.N oroviruses belong to a highly genetically and antigenically diverse genus Norovirus of the Caliciviridae family. Noroviruses are divided into five genogroups (GI, GII, GIII, GIV, and GV) according to the genetic similarity of highly conserved areas of their genomes, such as the RNA-dependent RNA polymerase and the VP1 protein (1), with GI, GII, and GIV associated with human diseases. They are important enteric pathogens responsible for at least 50% of all gastroenteritis outbreaks worldwide (2) and, partially due to their high infectivity and low infectious dose (18 to 1,000 virus particles) (3), human noroviruses (HuNoVs) are the most common cause of food-borne disease outbreaks in the United States (4).Transmission of HuNoV occurs primarily through exposure to contaminated food or water, person-to-person contact, aerosolized particles from vomitus, and contact with contaminated fomites (e.g., door handles, toilets, tables, and elevator buttons) (5). Numerous waterborne disease outbreaks have been linked to HuNoV (6-9), and HuNoVs are often detected in surface water (10), wastewater (11), and even finished drinking water (12). With respect to food-borne disease outbreaks, the most common food commodity implicated in HuNoV outbreaks is fresh produce, specifically leafy greens (13); however, the route of transmission and point of contami...

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