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Lohmann Ebbesen posted an update 3 weeks, 4 days ago
Menaquinone-7 (MK-7) is an important kind of vitamin K2 which plays significant roles in the treatment of coagulation and osteoporosis, and prevention of cardiovascular disease. This work was purposed to study the differences of gene expression at different oxygen supply conditions in Bacillus natto. The differences of fermentation characteristics, gene expression related to MK-7 biosynthesis, spore and biofilm formation were analyzed. The yield of MK-7 increased by two fold under high oxygen supply condition of 200 rpm. Further transcriptome analysis indicated that most of the enzymes in MK-7 biosynthesis pathway were also up-regulated. Moreover, glycerol kinase, fructose-bisphosphate aldolase and phosphofructokinase in glycolysis pathway were all up-regulated indicating that high oxygen supply can increase the consumption of substrate glycerol. Meanwhile, menD, encoded the rate-limiting enzyme in the MK pathway, was obviously up-regulated by 3.49-fold while most of the enzymes related to spore formation were down regulated at 200 rpm. Besides, superoxide dismutase (SOD2), catalase (CAT), hydroperoxide reductase (AhpF) and DNA-binding protein MrgA in the antioxidant defense system were up-regulated, while superoxide dismutase (SOD1) and glutathione peroxidase (GSH-Px) were down-regulated. These results could contribute to a better understanding for the effect of oxygen on the MK-7 production in Bacillus natto, and further analyze the molecular regulation mechanism of MK-7 biosynthesis.Fungi are a huge source of unexplored bioactive compounds. Owing to their biological activities, several fungi have shown commercial application in the health industry. Tuber aestivum Vittad. is one such edible fungi with an immense scope for practical biological applications. In the present study, the anti-angiogenic activity of petroleum ether and ethanol extracts of T. aestivum was investigated using the chick chorioallantoic membrane assay and compared to the positive controls silibinin and lenalidomide. Both the extracts showed a dose-dependent anti-angiogenic response. The extracts were also assessed for their anti-inflammatory potential by lipoxygenase-inhibition assay. The IC50 values for LOX inhibition assay, computed by the Boltzmann plot, were 368.5, 147.3 and 40.2 µg/mL, for the petroleum ether extract, ethanol extract, and the positive control ascorbic acid, respectively. The ethanol extract of T. aestivum showed superior anti-angiogenic and anti-inflammatory activity than the petroleum ether extract. Compositional investigation of the extracts by GC-MS revealed the presence of various bioactive compounds. The compounds were correlated to their anti-angiogenic and anti-inflammatory activity based on a meticulous literature search.With the increase of the demand of low flavouring smoked seafood products, there is a need of methodologies able to distinguish between different seafood treatments, as not all of them are allowed in all markers. Following this objective, in the present work an untargeted volatolomics approach was applied to identify volatile markers that demonstrate that Cold smoked products can be distinguished from Tasteless smoke neither Carbon monoxide treated seafood, which are prohibited in the European Union. The use of dynamic headspace for the volatile extraction followed by thermal desorption in combination with Gas Chromatography (GC) coupled to single quadrupole Mass Spectrometry (MS) has been employed for the determination of volatile composition of smoked fish. Data processing consisted on the use of PARADISe software, applied for GC/MS data treatment, followed by the multivariate analysis with PLS_Toolbox (MATLAB), and finally the creation and validation of statistical classification model. All 107 variables obtained allowed the construction of a model reaching the correct classification of 97% of the blind samples, while a simplified model with only 11 variables correctly classified up to 93% of the blind samples. These 11 compounds were elucidated to develop subsequent target volatolomics approaches, if needed. selleck Ordered according to the importance in the classification model, the elucidated compounds were 3-methyl-cyclopentanone, ethylbenzene, 2-methyl-2-cyclopenten-1-one, 2-methyl-benzofuran, furfuryl alcohol, 2-acetylfuran, acetophenone, guaiacol, 1-hydroxy-2-butanone, 4-vinylguaicol and acetoin. The results demonstrated the great potential of untargeted volatolomics for smoked seafood treatments classification.It has previously been shown that a novel blend of carbohydrates could preserve lobster meat after 6 months of frozen storage. Increased year-round demand for high-quality lobster may make selling to the frozen seafood market an unintended option for some fishermen. Yet, the chemical and sensory changes that occur in lobster meat after one-year frozen storage in this cryoprotectant blend is not known. The objective of this study was to determine the chemical and sensory characteristics of lobster frozen in five different solutions solution-1 (water); solution-2 (water + NaCl + STPP, sodium tripolyphosphate, 0.5%); solution-3 (water + NaCl + carbohydrate blend); solution-4 (water + NaCl + STPP, 0.25% + carbohydrate blend), and solution-5 (water + NaCl + STPP, 0.5% + carbohydrate blend). No difference (P > 0.05) existed among the treatments with regard to Malondialdehyde levels as a measure of lipid oxidation. Lobster frozen in the cryoprotectant showed increased tenderness, compared to the control which was frozen in water. The lobster meat treated with a combination of the carbohydrate blend and STPP had lower (P less then 0.05) moisture content than the control. In addition, consumers preferred (P less then 0.05) lobster frozen in the novel cryoprotectant blend and STPP with respect to flavour, texture, and overall acceptability compared to the control. Penalty analysis revealed that overall liking scores were positively associated with the attributes moist and sweet. In conclusion, the combination of the novel carbohydrate blend and STPP enhanced the sensory quality and the chemical properties of frozen lobster, which in turn extended the shelf-life of these products. These findings may have wide implications for the long-term preservation of frozen lobster meat.