Seasonal Changes in Food Uptake by the Sea Cucumber Apostichopus japonicus in a Farm Pond: Evidence from C and N Stable Isotopes

This study investigated the seasonal changes in carbon (C) and nitrogen (N) stable isotope values of several typical food sources of Apostichopus japonicus in a farm pond, including particulate organic matter (POM), macroalgae, benthic microalgae and animals such as nematode and copepod. The stable isotope technique was used to quantify relative contributions of various sources to the food uptake by A. japonicus. The results showed that significant changes occurred in the C and N stable isotope values of sea cucumber food sources due to the seasonality of micro-or macroalgae prosperity and the fluctuation of environmental conditions. The sea cucumber A. japonicus exhibited corresponding alterations in feeding strategy in response to the changes in food conditions. Calculation with a stable isotope mixing model showed that macroalgae was the principal food source for A. japonicus throughout the 1-yr investigation, with the relative contribution averaging 28.1% - 63.2%. The relative contributions of other food sources such as copepod and nematode, POM, benthic microalgae to the total food uptake by sea cucumber averaged 22.6% - 39.1%, 6.3% - 22.2%, 2.8% - 6.5%, and 2.8% - 4.2%, respectively. Together these results indicated that the seasonal changes in food sources led to the obvious temporal differences in the relative contribution of various food sources utilized by A. japonicus. Such findings provide the basic scientific information for improving the aquaculture techniques of A. japonicus, particularly for optimizing the food environment of A. japonicus culture in farm ponds.

Protective effects of Amaranthus hybridus against aflatoxin B1 and fumonisin B1-induced genotoxicity in H4IIE-luc cells

Aim:Protective effects of aqueous extract of Amaranthus hybridus against afl atoxin B1(AFB_(1))and/or fumonisin B1(FB_(1))on the H4IIE-luc cell line were determined by use of the methyl thiazol tetrazolium viability assay and disruption of DNA integrity.Methods:H4IIE-luc cells were incubated with different concentrations of AFB_(1) and/or FB_(1) for 24 and 48 h with or without aqueous extract of A.hybridus.Results:AFB_(1) decreased the viability of cells after 24 and 48 h of exposure.EC_(50)values for AFB_(1) were 10.5 and 1.8μmol/L for the two periods,respectively.When the 48 h exposure to mycotoxin repeated with a pre-treatment of 20 and 40μg/mL extract of A.hybridus,the EC_(50)changed to 3.88 and 7.67μmol/L,respectively.H4IIE-luc cells exposed to FB_(1) for 24 h responded more than those incubated for 48 h.Cells treated with a combination of AFB_(1) and FB_(1) were less viable with a signifi cant decrease in the greater concentration.The mixture of AFB_(1) and FB_(1) resulted in a signifi cant threat to H4IIE-luc as indicated by the absence or appearance of new bands in random amplifi ed polymorphic DNA analysis,which demonstrated damage to DNA.The protective effects were probably due to greater content of total phenolics,carotenoids,β-carotene,folic-,linolenic-,linoleic and palmitic acids,as well as calcium,magnesium,iron,zinc,and selenium observed in the extract.Conclusion:Exposure to 40μg/mL of extract of A.hybridus protected cells from damage to DNA by stabilizing DNA.

Aqueous extract of Corchorus olitorius decreases cytotoxicityof aflatoxin B1 and fumonisin B1 in H4IIE-luc cells

Aim:Afl atoxin B1(AFB1)and fumonisin B1(FB1)are important food-borne mycotoxins.Co-contamination of foodstuffs with these two mycotoxins is well-known and has been implicated in a possible development of hepatocellular carcinoma in humans living in regions of the world where exposures to these mycotoxins in grain are greatest.The aim of the current study was to evaluate the potential protective effects of an aqueous extract of Cochorus olitorius(C.olitorius,moroheiya)against cytotoxicity of AFB1 and/or FB1 in H4IIE-luc rat hepatoma cells,using assays to measure cell viability and disruption of DNA integrity.Although this transactivation assay was originally developed to specifi cally respond to aryl hydrocarbon agonists,this cell line was used because of its hepatic origin.Methods:H4IIE-luc cells were incubated with different concentrations of AFB1 and/or FB1 for 24 and 48 h with or without aqueous extract of C.olitorius.Results:Both mycotoxins decreased cell viability and increased DNA damage.Cytotoxicity was more pronounced when cells were exposed simultaneously to AFB1 and FB1.Conclusion:Aqueous extract of C.olitorius protected cells against cytotoxicity of mycotoxins.C.olitorius contains a water-soluble,natural chemo-preventative agent for cancer that should be isolated and identifi ed.