• Journal of Food Hygiene and Safety
• /
• v.37 no.4
• /
• pp.207-215
• /
• 2022

The intensity of fishy odor in eggs, which differs depending on the poultry type and individual perception, can be due to many factors including trimethylamine (TMA) which has been identified as the main. Notably, riboflavin can increase the activity of flavin-containing monooxygenase 3, the enzyme responsible for converting TMA into odorless trimethylamine-N-oxide. This study aimed to analyze the TMA content in egg yolk, evaluate its contribution to fishy odor, and develop a method to prevent this undesired odor. Solid-phase microextraction-gas chromatography/mass spectrometry was used to detect and quantify volatile compounds in egg yolk from hens fed a standard TMA-rich diet and hens fed a riboflavin-supplemented diet. To compare the relative content of volatile substances between eggs, a correlation study was performed using an electronic nose. Higher concentration of TMA (1.06 ± 0.12 mg/kg) was detected in egg yolks obtained from hens fed a normal diet than those fed a riboflavin-supplemented diet. Overall, this study suggests that riboflavin affects the quantity and quality of volatile substances, including TMA, present in eggs and we expect these findings to improve the quality and reduce the fishy odor of eggs.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1997.04a
• /
• pp.107-107
• /
• 1997

Cytochrome P450 enzymes have been intensively investigated in hepatic tissues and several mammalian cell lines. Compared to most studies about cytochrome P450 isozymes in liver in vivo and hepatic, cell lines in vitro, the study of cytochrome P450IA1 in human breast cancer cells could be very important to understand the mechanism of the regulation of CYPIA1 gene expression and cell growth. MCF-7 human breast cancer cells are well characterized to study estrogen and antiestrogen action due to the fact that they contain high level of estrogen receptor and have biological markers characterized. And also MCF-7 cells express high level of arylhydrocarbon hydroxylase activity and human cytochrome P450IA1 cDNA was cloned from MCF-7 cells. Ah receptor was characterized in many breast cancer cell lines and polycyclic aromatic hydrocarbon such as 3-MC induced the expression of CYPIA1 gene and cytochrome P450- dependent monooxygenase activity. We undertook a study to examine the effect of estrogens and other chemicals on the regulation of human CYPIA1 gene expression in MCF-7 cells via RTPCR analysis, that might help us to understand the mechanism of the regulation of CYPIA1 gene expression and MCF-7 cell growth. Expression vector containing the functional 5'-regulatory region of human CYPIA1 fused to the CAT reporter gene was transfected into estrogen receptor positive MCF-T cells or estrogen receptor negative MDA-MB-231 cells. After these cells were treated with various chemicals, RTPCR was carried out to measure both CYPIA1 mRNA and CAT mRNA levels. 1nM 3-MC increased in both P450 and CAT mRNA levels over those of control by two folds in MCF-7 cells but does not in MDA-MB-231 cells. Estrogen or tamoxifen or retinoic acid or chrysin decreased in both P450 and CAT mRNA levels that were induced by 3-MC in MCF-7 when each chemical was administered with 3-MC concomitantly. These results suggested that the level of CYPIA1 gene expression is modulated with estrogen-related molecules and make it possible to speculate that ER is related to CYPIA1 gene expression and cell growth in breast cancer cells. [Supported by grants from the Korean Ministry of Education ]

• 한국균학회소식:학술대회논문집
• /
• 2014.05a
• /
• pp.27-28
• /
• 2014

Beauveria bassiana (Cordycipitaceae, Hypocreales, Ascomycota) is an anamorphic fungus having a potential to be used as a biological control agent because it parasitizes a wide range of arthropod hosts including termites, aphids, beetles and many other insects. A number of bioactive secondary metabolites (SMs) have been isolated from B. bassiana and functionally verified. Among them, beauvericin and bassianolide are cyclic depsipeptides with antibiotic and insecticidal effects belonging to the enniatin family. Non-ribosomal peptide synthetases (NRPSs) play a crucial role in the synthesis of these secondary metabolites. NRPSs are modularly organized multienzyme complexes in which each module is responsible for the elongation of proteinogenic and non-protein amino acids, as well as carboxyl and hydroxyacids. A minimum of three domains are necessary for one NRPS elongation module: an adenylation (A) domain for substrate recognition and activation; a tholation (T) domain that tethers the growing peptide chain and the incoming aminoacyl unit; and a condensation (C) domain to catalyze peptide bond formation. Some of the optional domains include epimerization (E), heterocyclization (Cy) and oxidation (Ox) domains, which may modify the enzyme-bound precursors or intermediates. In the present study, we analyzed genomes of B. bassiana and its allied species in Hypocreales to verify the distribution of NRPS-encoding genes involving biosynthesis of beauvericin and bassianolide, and to unveil the evolutionary processes of the gene clusters. Initially, we retrieved completely or partially assembled genomic sequences of fungal species belonging to Hypocreales from public databases. SM biosynthesizing genes were predicted from the selected genomes using antiSMASH program. Adenylation (A) domains were extracted from the predicted NRPS, NRPS-like and NRPS-PKS hybrid genes, and used them to construct a phylogenetic tree. Based on the preliminary results of SM biosynthetic gene prediction in B. bassiana, we analyzed the conserved gene orders of beauvericin and bassianolide biosynthetic gene clusters among the hypocrealean fungi. Reciprocal best blast hit (RBH) approach was performed to identify the regions orthologous to the biosynthetic gene cluster in the selected fungal genomes. A clear recombination pattern was recognized in the inferred A-domain tree in which A-domains in the 1st and 2nd modules of beauvericin and bassianolide synthetases were grouped in CYCLO and EAS clades, respectively, suggesting that two modules of each synthetase have evolved independently. In addition, inferred topologies were congruent with the species phylogeny of Cordycipitaceae, indicating that the gene fusion event have occurred before the species divergence. Beauvericin and bassianolide synthetases turned out to possess identical domain organization as C-A-T-C-A-NM-T-T-C. We also predicted precursors of beauvericin and bassianolide synthetases based on the extracted signature residues in A-domain core motifs. The result showed that the A-domains in the 1st module of both synthetases select D-2-hydroxyisovalerate (D-Hiv), while A-domains in the 2nd modules specifically activate L-phenylalanine (Phe) in beauvericin synthetase and leucine (Leu) in bassianolide synthetase. antiSMASH ver. 2.0 predicted 15 genes in the beauvericin biosynthetic gene cluster of the B. bassiana genome dispersed across a total length of approximately 50kb. The beauvericin biosynthetic gene cluster contains beauvericin synthetase as well as kivr gene encoding NADPH-dependent ketoisovalerate reductase which is necessary to convert 2-ketoisovalarate to D-Hiv and a gene encoding a putative Gal4-like transcriptional regulator. Our syntenic comparison showed that species in Cordycipitaceae have almost conserved beauvericin biosynthetic gene cluster although the gene order and direction were sometimes variable. It is intriguing that there is no region orthologous to beauvericin synthetase gene in Cordyceps militaris genome. It is likely that beauvericin synthetase was present in common ancestor of Cordycipitaceae but selective gene loss has occurred in several species including C. militaris. Putative bassianolide biosynthetic gene cluster consisted of 16 genes including bassianolide synthetase, cytochrome P450 monooxygenase, and putative Gal4-like transcriptional regulator genes. Our synteny analysis found that only B. bassiana possessed a bassianolide synthetase gene among the studied fungi. This result is consistent with the groupings in A-domain tree in which bassianolide synthetase gene found in B. bassiana was not grouped with NRPS genes predicted in other species. We hypothesized that bassianolide biosynthesizing cluster genes in B. bassiana are possibly acquired by horizontal gene transfer (HGT) from distantly related fungi. The present study showed that B. bassiana is the only species capable of producing both beauvericin and bassianolide. This property led to B. bassiana infect multiple hosts and to be a potential biological control agent against agricultural pests.

• Journal of Life Science
• /
• v.20 no.1
• /
• pp.133-141
• /
• 2010

The protective effect of a mixed powder from solid-cultured and liquid-cultured Lentinus edodes mycelia (2:1, w/w) (designate LED) on the carbon tetrachloride ($CCl_4$)- and ethanol-induced hepatotoxicity of male Sprague-Dawley (SD) rat was investigated. In the $CCl_4$-induced rat hepatotoxicity experiment, rats of 4 groups (6 rats/group) were administere with Normal (0.2 ml distilled water), Control (0.2 ml distilled water), LED (LED 200 mg/kg BW + 0.2 ml distilled water), and Silymarin (200 mg/kg BW + 0.2 ml distilled water), p.o., daily for 2 weeks. Afterwards, all groups except for the Normal group were subjected to abdominal injection with $CCl_4$ ($CCl_4$ : corn oil, 1:1 v/v; 0.5 ml/kg BW). For the ethanol- induced rat hepatotoxicity experiment, rats were divided into 5 groups (5 rats/group): Normal; Pair-fed control (PFC); Control (ethanol); LED (ethanol + LED 200 mg/kg BW); and Silymarin (ethanol + silymarin 200 mg/kg BW). Rats of the Normal and PFC groups were fed a basal liquid diet, and rats of the Control, LED, and Silymarin groups were fed a liquid ethanol diet containing LED or Silymarin. Eight weeks later, blood and liver samples were collected to analyze biomarkers. In $CCl_4$-induced SD rats, LED elevated hepatic superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH peroxidase) activities and thiobarbituric reactive substances (TBARS) were reduced, resulting in the reduction of glutamate-oxalate transaminase (GOT), glutamate-pyruvate transaminase (GPT) and lactic dehydrogenase (LDH) activities in plasma. Similar results of these enzymes and biochemical markers in both liver tissues and plasma were seen in ethanol-induced hepatotoxicity of SD rats. In addition, elevated alcohol dehydrogenase (ADH) activity and reduced expression of cytochrome p450 mixed monooxygenase enzyme (CYP2E1) were seen in liver tissues from ethanol-treated rats by LED treatment. These effects of LED were similar to those of Silymarin. In in vitro experiments, LED showed antioxidant activity in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) system and mouse liver mitochondria system induced by NADPH/$Fe^{2+}$ and cumine hydroperoxide (CuOOH). These results indicate that LED protected SD rat hepatotoxicity, induced by $CCl_4$ and ethanol, through its antioxidative activity and might be useful as a material for protection from hepatoxicity in humans.