• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.173-178
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• 2001

Food yeast, Saccharomyces cerevisiae, is a safe organism with a long history of use for the production of biomass rich in high quality proteins and vitamins. AmA1, a seed storage albumin from Amaranthus hypochondriacus, has a well-balanced amino acid composition and high levels of essential amino acids and offers the possibility of further improving food animal feed additives. In order to find an effective means of expressing AmA1 in yeast, the gene was cloned into an episomal shuttle vector. Four different promoters were tested: the glyceraldehyde-3-phosphate dehydrogenase promoter, galactose dehydrogenase 10 promoter, alcohol dehydrogenase II promoter, and a hybrid ADH2-GPD promoter. The recombinant AmA1 genes were then introduced into the yeast Saccharomyces cerevisiae 2805. Northern and Western blot analyses of the yeast under appropriate conditions revealed that AmA1 was expressed by all four promoters at varying levels. An enzyme-linked immunosorbent assay demonstrated that the amount of AmA1 protein in the recombinant yeast was 1.3-4.3% of the total soluble proteins. The highest expression level was obtained from the hybrid ADH2-GPD promoter.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.801-806
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• 2002

A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.29-35
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• 1977

Seven strains of methanol assimilating yeasts were isolated from soil enriched with tetracycline. Among them two better growing strains were selected and partially identified as species belonging to genus Candida. The both Candida 1-B and 25-A, grew best under conditions of pH 5.0 and 28$^{\circ}C$. The optimal methol concentration in the medium was found to be 1％, Whereas the organism, could grow up to the 4％ level. Biotin was required by the organisms for growth and organic nitrogen sources raised the rate of growth. The field of biomass per unit weight of consumed methanol after 96 hours were 36.9％ by Candida 1-B and 39.2％ by 25-A.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.51-56
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• 1998

A bacteium, KP-6408, capable of hydrolyzing fibrin was isolated from Chungkook-jang, which was possibly identified as a strain of Bacillus sp. The effects of culture condition and medium composition on the enzyme production were investigated. Among nitrogen sources tested, yeast extract was the most effective for the enzyme production, and the level of the concentration for the optimal enzyme production was 0.2%(w/v). For carbon sources, glucose was the best for the enzyme production with the level of 2.0%(w/v). The enzyme was maximally produced by cultivating the enzyme production with the level of 2.0%(w/v). The enzyme was maximally produced by cultivating the organism at the liquid medium of the initial pH 8.0 and temperature of 4$0^{\circ}C$. In Chungkook-jang fermentation, the enzyme was maximally produced when incubated at 35$^{\circ}C$ for 24 hrs using soybean as a solid medium. The addition of various rice starch to the soybean in Chungkook-jang fermentation lowered the enzyme production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.178-190
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• 1999

This study was conducted to develop a simulation model for the growth dynamics of pigs and to describe quantitatively protein deposition depending on the amino acid composition of feed protein. In the model it is assumed that the essential processes that determine the utilization of feed protein in the whole body are protein synthesis, breakdown of protein, and oxidation of amino acid. Besides, it is also assumed that occurrence of protein deposition depends on genetic potential and amino acid composition of feed protein. The genetic potential for the protein deposition is the maximum capacity of protein synthesis, being dependent on the protein mass of the whole body. To describe the effect of amino acid composition of feed on the protein deposition, a factor, which consist of ten amino acid functions and lie between 0 and 1, is introduced. Accordingly a model was developed, which is described with 15 flux equations and 11 differential equations and is composed of two compartments. The model describes non linear structure of the protein utilization system of an organism, which is in non steady state. The objective function for the simulation was protein deposition(g/day) cal culated according to the empirical model, PAF(product of amino acid functions) of Menke. The mean of relative difference between the simulated protein deposition and PAF calculated values, lied in a range of 11.8%. The simulated protein synthesis and breakdown rates(g/day) in the whole body showed a parallel behavior in the course of growth.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1337-1340
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• 2008

The objective of this study was to evaluate the microbial safety of raw beef used to produce Korean beef jerky, The raw beef samples harbored large populations of microorganisms. In particular, psychrophilic bacteria were found to be most numerous ($9.2{\times}10^3-1.0{\times}10^5\;CFU/g$) in the samples. Mesophilic bacteria and anaerobic bacteria were present in average numbers ($10^3-10^5\;CFU/g$). Spore-forming bacteria and coliforms were not detected below detection limit. Yeast and molds were detected at $2.2{\times}10^1-7.8{\times}10^2\;CFU/g$ in the raw beef. Ten samples of raw beef were analyzed for the presence of pathogenic bacteria. Bacillus cereus was isolated from sample B, G, and H. The B. cereus isolates from raw beef samples were identified with 99.8% agreement according to the API CHB 50 kit.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1357-1360
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• 2008

Propionibacterium acnes is the predominant organism in sebaceous regions of the skin and is thought to play an important role in the pathogenesis of inflamed lesions. Antibacterial compounds against P. acnes were isolated from the ethanol extract of Kaempferia pandurata Roxb. and identified as panduratin A and isopanduratin A. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panduratin A for P. acnes were 2 and $4{\mu}g/mL$, respectively, while those of isopanduratin A were 4 and $8{\mu}g/mL$, respectively. The time-dependent killing effect showed that panduratin A and isopanduratin A completely inhibited the growth of P. acnes at 4 and $8{\mu}g/mL$ in 48 hr, respectively. Panduratin A and isopanduratin A demonstrated high antibacterial activities not only against P. acnes but also other skin microorganisms. The results suggest that panduratin A and isopanduratin A could be employed as natural antibacterial agents to inhibit the growth of acne and skin disease causing microorganisms.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.676-685
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• 2021

RNA-binding proteins are involved in RNA metabolism and posttranscriptional regulation of various fundamental biological processes. The PUF family of RNA-binding proteins is highly conserved in eukaryotes, and its members regulate gene expression, mitochondrial biogenesis, and RNA processing. However, their biological functions in Aspergillus species remain mostly unknown in filamentous fungi. Here we have characterized the puf genes in the model organism Aspergillus nidulans. We generated deletion mutant strains for the five putative puf genes present in the A. nidulans genome and investigated their developmental phenotypes. Deletion of pufA or pufE affected fungal growth and asexual development. pufA mutants exhibited decreased production of asexual spores and reduced mRNA expression of genes regulating asexual development. The pufE deletion reduced colony growth, increased formation of asexual spores, and delayed production of sexual fruiting bodies. In addition, the absence of pufE reduced both sterigmatocystin production and the mRNA levels of genes in the sterigmatocystin cluster. Finally, pufE deletion mutants showed reduced trehalose production and lower resistance to thermal stress. Overall, these results demonstrate that PufA and PufE play roles in the development and sterigmatocystin metabolism in A. nidulans.

• BMB Reports
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• v.57 no.1
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• pp.50-59
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• 2024

The application of gene engineering in livestock is necessary for various reasons, such as increasing productivity and producing disease resistance and biomedicine models. Overall, gene engineering provides benefits to the agricultural and research aspects, and humans. In particular, productivity can be increased by producing livestock with enhanced growth and improved feed conversion efficiency. In addition, the application of the disease resistance models prevents the spread of infectious diseases, which reduces the need for treatment, such as the use of antibiotics; consequently, it promotes the overall health of the herd and reduces unexpected economic losses. The application of biomedicine could be a valuable tool for understanding specific livestock diseases and improving human welfare through the development and testing of new vaccines, research on human physiology, such as human metabolism or immune response, and research and development of xenotransplantation models. Gene engineering technology has been evolving, from random, time-consuming, and laborious methods to specific, time-saving, convenient, and stable methods. This paper reviews the overall trend of genetic engineering technologies development and their application for efficient production of genetically engineered livestock, and provides examples of technologies approved by the United States (US) Food and Drug Administration (FDA) for application in humans.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.317-319
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• 1999

The ciliate, Vorticella was often observed in the rotifer mass culture tanks as common co-existing organism. This Vorticella performed as a predator for aquatic bacteria population in the rotifer mass culture tanks. This study was carried out to investigate a cyst formation medium of Vorticella in the laboratory for keeping Vorticella seed. The test organism Vorticella sp. was isolated from culture water of rotifer mass culture tanks. The cyst of Vorticella was formed by dried-method for the formation and maintainance of cyst. MCCF (Marine Ciliate Cyst Formation) medium was used for cyst formation (incystment), preservation and return to moving cell (excystment) of the marine ciliate, Vorticella sp. The cyst shape and size were ellipical type and $30.51 \pm1.98\;\mu$m (Avg. $\pm$ SD) of minor axis and $28.89 \pm2.12\;\mu$m (Avg. $\pm$ SD) of minor axis (n=10), The Vorticella cyst was kept in the room temperature ($10\~35^{\circ}C$) and total dark condition (24D:0L) during 1 year. The preserved cyst was transferred to moving cell state (excystment) only by the addition of fresh sea water in the MCCF medium. The five Vorticella sp. moving cells of excysted from cysts showed the growth up to 912$\pm$64 cells/10 ml in MCCF medium during the culture period of 16 days. This MCCF medium was very useful tool for cyst formation and species preservation of marine ciliate Vorticella.