• The Korean Journal of Mycology
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• v.51 no.3
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• pp.205-217
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• 2023

This study aimed to produce novel bioactive compounds from non-pathogenic pigmented wild yeasts. Culture supernatants and cell-free extracts of non-pathogenic pigmented yeast strains were prepared, and their physiological functionalities and enzyme activities were measured. Cell-free extracts from Rhodosporidium paludigenum HHGG35-1 and culture supernatants from Rhodosporidium diobovatum NMD18-1 demonstrated very high antioxidant activity (76.6%) and anti-gout xanthin oxidase inhibitory activity (86.2%), respectively. Maximal production of the antioxidants (76.9%) was obtained when Rh. Paludigenum HHGG35-1 was cultured in a yeasts extract-peptone-dextrose (YPD) medium (pH 6.5) at 30℃ for 24 h. The xanthin oxidase inhibitor was also maximally produced (91.6%) when Rh. Diobovatum NMD18-1 was cultured at 30℃ for 96h in a YPD medium (pH 6.5). Rh. Paludigenum HHGG35-1 was oval in shape and formed ascospre. The Rh.diobovatum NMD18-1 specimen displayed dimensions of 1.6 × 1.6 ㎛ and produced ascospores; however, it did not form pseudomycelium. Both of Rh. Paludigenum HHGG35-1 and Rh. Diobovatum NMD18-1 grew well in a 40%-glucose-containing YPD medium and 10%-NaCl-containing YPD medium.

• Journal of Nutrition and Health
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• v.3 no.3
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• pp.129-135
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• 1970

From the previous studies, F-P-4 formula was found to be comparable to full fat dry milk in its nutritive value and feeding performance. However, an attempt was made in order to make sure whether or not any possibility might exist, by which further improvement of nutritive quality and simultaneous reduction of product costs may be achieved. Using F-P-4 as a control, modifications were made in new formulas, F-P-5, F-P-6 and F-P-7 by reducing FPC, eliminating yeast from the mixture, and by enriching with methionine as needed. In particular, F-P-7 is completely free of FPC, hydrogenated oil and yeast. Yet, levels of total protein and fat were kept equal to those of F-P-4 in all formulas. An animal feeding test for all formulas using 10 female rats per group for 8 weeks and an infant feeding trial for F-P-5 and F-P-6 with 5 of each female infants under age of one for one month were conducted along with F-P-4 as a control. Almost the same results were obtained with F-P-4, 5 and 6, but F-P-7 showed the lowest body weight gain. FER of F-P-5 and 6 was 0.20 as was with F-P-4, while that of F-P-7 was 0.16. Acceptability to infants was excellent; growth, appearance and biochemical data were normal. As an example F-P-4 packed in 0.04mm polyethylene bags was used for storage study at $25^{\circ}C$ and relative humidity of $65{\sim}85%$ for 8 months. Although viable bacterial counts and vitamin C contents were reduced, peroxide and TBA values were increased gradually during such storage. Since there are also significant changes in color and organoleptic quality, the expected shelf life under the given conditions is considered to be about 2 months and thus further works are needed both on the product and packaging in order to improve the storage stability. Either elimination of yeast form F-P-4, that is F-P-5, or partial replacement of FPC with methionine, that is F-P-6 may well reduce material costs about 10%. Considering blending process of ingredients, F-P-5 is thus found to be the best formula developed. While F-P-7 free of FPC is inferior in its nutritive quality than that of others, but significantly superior than of rice. Furthermore, the material cost of the product can be reduced about 20% from that of F-P-4. And thus this vegetable blend is considered to be useful as a low cost supplementary food mixture for growing children.

• Journal of Life Science
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• v.31 no.3
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• pp.257-265
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• 2021

Heterotrimeric kinesin-2 is a molecular motor protein of the kinesin superfamily (KIF) that moves along a microtubule plus-end directed motor protein. It consists of three different motor subunits (KIF3A, KIF3B, and KIF3C) and a kinesin-associated protein 3 (KAP3) that form a heterotrimeric complex. Heterotrimeric kinesin-2 interacts with many different binding proteins through the cargo-binding domain of the KIF3s. The activity of heterotrimeric kinesin-2 is regulated to ensure that the cargo is directed to the right place at the right time. How this regulation occurs, however, remains in question. To identify the regulatory proteins for heterotrimeric kinesin-2, we performed yeast two-hybrid screening and found a specific interaction with creatine kinase B (CKB), which is the brain isoform of cytosolic creatine kinase enzyme. CKB bound to the cargo-binding domain of KIF3A but did not interact with the KIF3B, KIF5B, or KAP3 in the yeast two-hybrid assay. The carboxyl (C)-terminal region of CKB is essential for the interaction with KIF3A. Another protein kinase, CaMKIIa, interacted with KIF3A, but GSK3a did not interact with KIF3A in the yeast two-hybrid assay. KIF3A interacted with GST-CKB-C but not with GSK-CKB-N or GST alone. When co-expressed in HEK-293T cells, CKB co-localized with KIF3A and co-immunoprecipitated with KIF3A and KIF3B but not KIF5B. These results suggest that the CKB-KIF3A interaction may regulate the cargo transport of heterotrimeric kinesin-2 under energy-compromised conditions in cells.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.928-937
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• 2016

S-Nitrosoglutathione reductase (GSNOR) metabolizes S-nitrosoglutathione (GSNO) and has been shown to play important roles in regulating cellular signaling and formulating host defense by modulating intracellular nitric oxide levels. The enzyme has been found in bacterial, yeast, mushroom, plant, and mammalian cells. However, to date, there is still no evidence of its occurrence in filamentous fungi. In this study, we cloned and investigated a GSNOR-like enzyme from the filamentous fungus Aspergillus nidulans. The enzyme occurred in native form as a homodimer and exhibited low thermal stability. GSNO was an ideal substrate for the enzyme. The apparent K_m and k_cat values were 0.55 mM and 34,100 min^-1, respectively. Substrate binding sites and catalytic center amino acid residues based on those from known GSNORs were conserved in this enzyme, and the corresponding roles were verified using site-directed mutagenesis. Therefore, we demonstrated the presence of GSNOR in a filamentous fungus for the first time.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1827-1834
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• 2015

The SMG1 lipase from Malassezia globosa is a newly found mono- and diacylglycerol (DAG) lipase that has a unique lid in the loop conformation that differs from the common alpha-helix lid. In the present study, we characterized the contribution of three residues, L103 and F104 in the lid and F278 in the rim of the binding site groove, on the function of SMG1 lipase. Site-directed mutagenesis was conducted at these sites, and each of the mutants was expressed in the yeast Pichia pastoris, purified, and characterized for their activity toward DAG and p-nitrophenol (pNP) ester. Compared with wild-type SMG1, F278A retained approximately 78% of its activity toward DAG, but only 11% activity toward pNP octanoate (pNP-C8). L103G increased its activity on pNP-C8 by approximately 2-fold, whereas F104G showed an approximate 40% decrease in pNP-C8 activity, and they both showed decreased activity on the DAG emulsion. The deletion of 103-104 retained approximately 30% of its activity toward the DAG emulsion, with an almost complete loss of pNP-C8 activity. The deletion of 103-104 showed a weaker penetration ability to a soybean phosphocholine monolayer than wild-type SMG1. Based on the modulation of the specificity and activity observed, a pNP-C8 binding model for the ester (pNP-C8, N102, and F278 form a flexible bridge) and a specific lipid-anchoring mechanism for DAG (L103 and F104 serve as "anchors" to the lipid interface) were proposed.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.283-288
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• 1995

This study was carried out to investigate the toxic action of herbicide, paraquat(1,1'-dimethyl-4,4'-bipyridylium-dichloride), against microorganisms. The toxic effect of paraquat was observed mainly using Escherichia coli(KCTC 1039), as follows; Growth of aerobic microorganisms which comprise 4 strains of bacteria and 2 strains of yeast and 4 strains of mold was inhibited drastically in the presence of 1.0mM paraquat But the growth of anaerobic bacteria was not affected by the chemical. When actively growing cells of E. coli were exposed to the paraquat at the concentration higher than 1.0 mM, they rapidly lost their ability to form colony and clearly formed inhibitory zone by well test More than 50% of the cells were killed by 1.0 mM paraquat treatment, even at immediate addition of paraquat to the medium.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.936-940
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• 2015

Human papillomavirus (HPV) type 52 is a high-risk HPV responsible for cervical cancer. HPV type 52 is common around the world and is the most common in some Asian regions. The available prophylactic HPV vaccines protect only from HPV types 16 and 18. Supplementing economical vaccines that target HPV type 52 may satisfactorily complement available prophylactic vaccines. A codon-adapted HPV 52 L1 gene was expressed in the methylotrophic yeast Hansenula polymorpha, which is used as an industrial platform for economical hepatitis B surface antigen particle production in China. We found that the recombinant proteins produced in this expression system could form virus-like particles (VLPs) with diameters of approximately 50 nm. This study suggests that the HPV 52 VLPs produced in this platform may satisfactorily complement available prophylactic vaccines in fighting against HPVs prevalent in Asia.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1221-1225
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• 2007

A ${\beta}$-ionone-resistant mutant strain isolated from the red yeast Xanthophyllomyces dendrorhous KCTC 7704 was used for batch and continuous fermentation kinetic studies with glucose media in a 2.5-1 jar fermentor at $22^{\circ}C$ and pH 4.5. The kinetic pattern of growth and carotenoid concentration in the batch fermentations exhibited a so-called mixed-growth-associated product formation, possibly due to the fact that the content of intracellular carotenoids depends on the degree of physical maturation toward adulthood. To determine the maximum specific growth rate constant (${\mu}_m$) and Monod constant ($K_s$) for the mutant, glucose-limited continuous culture studies were performed at different dilution rates within a range of $0.02-0.10\;h^{-1}$. A reciprocal plot of the steady-state data (viz., reciprocal of glucose concentration versus residence time) obtained from continuous culture experiments was used to estimate a ${\mu}_m$ of $0.15\;h^{-1}$ and $k_s$ of 1.19 g/l. The carotenoid content related to the residence time appeared to assume a typical form of saturation kinetics. The maximum carotenoid content ($X_m$) for the mutant was estimated to be $1.04\;{\mu}g/mg$ dry cell weight, and the Lee constant ($k_m$), which was tentatively defined in this work, was found to be 3.0 h.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.730-746
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• 2015

Selenium plays an important role in boar nutrition via participating in selenoprotein synthesis. It seems likely that selenoproteins are central for antioxidant system regulation in the body. Se-dependent enzyme glutathione peroxidase (GSH-Px) is the most studied selenoprotein in swine production. However, roles of other selenoproteins in boar semen production and maintenance of semen quality also need to be studied. Boar semen is characterised by a high proportion of easily oxidized long chain polyunsaturated fatty acids and requires an effective antioxidant defense. The requirement of swine for selenium varies depending on many environmental and other conditions and, in general, is considered to be 0.15 to 0.30 mg/kg feed. It seems likely that reproducing sows and boars are especially sensitive to Se deficiency, and meeting their requirements is an important challenge for pig nutritionists. In fact, in many countries there are legal limits as to how much Se may be included into the diet and this restricts flexibility in terms of addressing the Se needs of the developing and reproducing swine. The analysis of data of various boar trials with different Se sources indicates that in some cases when background Se levels were low, there were advantages of Se dietary supplementation. It is necessary to take into account that only an optimal Se status of animals is associated with the best antioxidant protection and could have positive effects on boar semen production and its quality. However, in many cases, background Se levels were not determined and therefore, it is difficult to judge if the basic diets were deficient in Se. It can also be suggested that, because of higher efficacy of assimilation from the diet, and possibilities of building Se reserves in the body, organic selenium in the form of selenomethionine (SeMet) provided by a range of products, including Se-Yeast and SeMet preparations is an important source of Se to better meet the needs of modern pig genotypes in commercial conditions of intensive pig production.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.807-812
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• 2002

In order to analyze the cellular proteins which interact with core protein of hepatitis C virus (HCV), a yeast two-hybrid screening technique was employed. A carboxyl terminus truncated core protein, which contained amino acid residues from the 1st to 120th, was used as a bait to screen cellular proteins. The expression library prepared from HeLa cell was screened and 400 positive clones were selected. The 75 clones from the positive clones were sequenced and analyzed by undergoing the Blast search. Interestingly, 7 out of the 75 clones encoded E7 antigen of human papilloma virus (HPV). We studied in detail the Interaction between the truncated version of HCV core and E7 antigen in vitro. The core$_{120}$ protein expressed in chimeric form with G57 was able to bring down the E7 protein of HPV type 18 expressed in bacteria. It is therefore suggested that the core of HCV might affect the interaction between E7 and a normal cellular tumor suppressor, known as Rb protein.