• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.542-544
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• 2002

This study was carried out to evaluate the ciliates Euplotes sp. as a live food for marine fish larvae. The ciliates and the rotifers Brachionus plicatilis, which were cultured with the baker's yeast Saccharomyces cerevisiae and the $\omega$-yeast emulsified with cuttle fish liver oil, were supplied to the larvae of flounder Paralichthys olivaceus and grouper Epinephelus akaara. Considering the size difference between the ciliates 68 $\cdot$ 7 $\mu$n and the rotifers 160 $\cdot$ 20 $\mu$n, the rotifers and ciliates were supplied to the larvae tank with the density of 2 inds./mL and 20 inds./mL, respectively. The survival rate and growth in length of the flounder larvae fed on rotifer were significantly higher than those on Euplotes sp.. In grouper larvae which have a small mouth diameter, even the survival rate of the larvae fed on the ciliates was better than that on the rotifers, it was very low less than $20\%$. Therefore, Euplotes sp. seem to be incongruent as a live food for marine fish larvae.

• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.284-288
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• 2005

Baker's yeast was disrupted in a 1.4-L stainless steel horizontal bead mill under a continuous recycle mode using 0.3 mm diameter zirconia beads as abrasive. A single pass in continuous mode bead mill operation liberates half of the maximally released protein. The maximum total protein release can only be achieved after passaging the cells 5 times through the disruption chamber. The degree of cell disruption was increased with the increase in feeding rate, but the total protein release was highest at the middle range of feeding rate (45 L/h). The total protein release was increased with an increase in biomass concentration from 10 to $50\%$(w/v). However, higher heat dissipation as a result of high viscosity of concentrated biomass led to the denaturation of labile protein such as glucose 6-phosphate dehydrogenase (G6PDH). As a result the highest specific activity of G6PDH was achieved at biomass concentration of $20\%$(ww/v). Generally, the degree of cell disruption and total protein released were increased with an increase in impeller tip speed, but the specific activity of G6PDH was decreased substantially at higher impeller tip speed (14 m/s). Both the degree of cell disruption and total protein release increased, as the bead loading increased from 75 to $85\% (v/v)$. Hence, in order to obtain a higher yield of labile protein such as G6PDH, the yeast cell should not be disrupted at biomass concentration and impeller tip speed higher than $20\%(w/v)$ and 10 m/s, respectively.

• Korean Journal of Food Science and Technology
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• v.13 no.3
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• pp.181-187
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• 1981

The changes in the chemical composition of yeast extracts during autolysis and their effect to the sensory quality were studied with baker's yeast, Saccharomyces cerevisiae. The amounts of extracted solids, proteins, amio-N. amino acids, especially glutamic acid, alanine and lysine, increased by the autolysis time up to 48 hrs. The results of sensory evaluation made by the multiple paired comparision test and Duncan's test indicated a significant difference is taste by the time of autolysis. In the profile test, the flavor character notes expressed by the panel were 17 different characters, 11 in aroma and 6 in taste. The character notes and the intensity of flavor changed with the time of autolysis. The sharp and beany flavor of the extracts which was autolyzed for 4 hours turned into meaty and worty flavor by 48 hours of autolysis. A proper arrangement of the flavor characters in the quantitative descriptive chart could provide a weighted value of the flavor grade. The aroma grade index and the taste grade index correlated to the amplitudes of the profile test.

• BMB Reports
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• v.38 no.6
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• pp.661-667
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• 2005

Since conflicting results have been reported on non-specific immune response in type 1 diabetes, this study evaluates polymorphonuclear neutrophil (PMN) functions in the infection free Long Evan diabetic rats (type 1) by using tests that include: polarization assay, phagocytosis of baker's yeasts (Saccharomyces cerevisiae) and nitroblue tetrazolium (NBT) dye reduction. Polarization assay showed that neutrophils from diabetic rats were significantly activated at the basal level compared to those from the controls (p < 0.001). After PMN activation with N-formyl-methionyl-leucyl-phenylalanine (FMLP), control neutrophils were found to be more polarized than those of the diabetic neutrophils and the highest proportions of polarization were found to be 67% and 57% at $10^{-7}\;M$ FMLP, respectively. In the resting state, neutrophils from the diabetic rats reduced significantly more NBT dye than that of the controls (p < 0.001). The percentages of phagocytosis of opsonized yeast cells by the neutrophils from control and diabetic rats were 87% and 61%, respectively and the difference was statistically significant (p < 0.001). Evaluation of the phagocytic efficiency of PMNs revealed that control neutrophils could phagocytose $381{\pm}17$ whereas those from the diabetic rats phagocytosed $282{\pm}16$ yeast cells, and the efficiency of phagocytosis varied significantly (p < 0.001). Further, both the percentages of phagocytosis and the efficiency of phagocytosis by the diabetic neutrophils were inversely related with the levels of their corresponding plasma glucose (p = 0.02; r = -0.498 and p < 0.05; r = -0.43, respectively), which indicated that increased plasma glucose reduced the phagocytic ability of neutrophils. Such relationship was not observed with the control neutrophils. These data clearly indicate that PMN functions are altered in the streptozotocin (STZ) - induced diabetic rats, and hyperglycemia may be the cause for the impairment of their functions leading to many infectious episodes.

• Korean Journal of Microbiology
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• v.21 no.4
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• pp.221-228
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• 1983

An improved procedure for the rapid purification of glucose-6-phosphate dehydrogenase from extracts of Saccharomyces cerevisiae was developed by using affinity chromatography. Among six affinty media tested, $NADP^+ -agarose$ and Affi-gel Blue were more effective than others (i.e., Affi-gel Red, AMP-agarose, ATP-agarose, and $NAD^+ -agarose$). Conditions to desorb the enzyme bound to the affinity media were examined to increase the purity as well as yield. The best result was obtained when the column was developed with a linear gradient of KCl (0-1.0M). In case of Affi-gel Blue, introduction of $NAD^+$ (15mM) washing step prior to the salt gradient was most effective to remove $NAD^+ -binding$ proteins. For a large scale preparation of G-6-P dehydrogenase higher recovery was obtained by Affi-gel Blue than $NADP^+ -agarose$, however, the purity of the enzyme was decreased by 10 times if the former was used as the affinity medium. The capacity of Affi-gel Blue for G-6-P dehydrogenase was found to be 5 times higher than that of $NADP^+ -agarose$. Furthermore Affi-gel Blue could be reused repeatedly and its preparation is relatively easier and less expensive than $NADP^+ -agarose$.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.593-599
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• 2007

In this study, we examined the volatile flavor components in the mashes of takju prepared using different yeasts such as Saccharomyces coreanus, S. ellipsoideus, S. carlsbergensis, S. cerevisiae (Baker's yeast), and S, rouxii by GC and GC-MS. Fourteen alcohols, 13 esters, 5 acids, 3 aldehydes, 7 amines, and 2 other compounds were identified in the mash after 6 days of fermentation. On day 6, the takju fermented by S. coreanus had the greatest variety of volatile flavor components. Fifteen flavor components, including ethanol, isobutyl alcohol, isoamyl alcohol, methyl pentanol, 1,3-butanediol, 3-methylthio-1-propanol, benzeneethanol, ethyl lactate, acetic acid, acetaldehyde, and 1,3-cyclohexane diamine, were typically detected in all the treatments. The relative peak areas of the volatile components were as follows: alcohols (96.758-99.387%), esters (0.081-0.968%), acids (0.040-0.640%), aldehydes (0.266-0.959%), and amines (0.011-0.047%). In particular, 1-propanol, isobutyl alcohol, 3-methyl-1-butanol, 2,3-butanediol, trimethyl benzylalcohol, heptene-2,4-diol, ethyl lactate, diethyl succinate, ethyl nonanoate, methyl hexadecanoate, linoleic acid, hexadecanoic acid, and acetaldehyde were hish in the takju made by S. coreanus. Also, ethyl stearate was high in the takju made by S. carlsbergensis, and hexanoic acid was high in the takju made by S. cerevisiae. Finally, methyl pentanol, 1,3-butanediol, 3-methylthio-1-propanol, benzene ethanol, ethyl octadecanoate, acetic acid, pentanal, and 1,3-cyclohexane diamine were high in the takju made by S. rouxii.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.73-77
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• 2002

The Sec61 trimeric complex ($\alpha$,$\beta$, and ${\gamma}$ subunits) is one of the Sec-complex responsible for post-translational protein translocation across the endoplasmic reticulum membrane in diverse organisms. In this study, a cDNA encoding the Sec61p ${\gamma}$ subunit homologue was isolated from the cDNA library of the mole cricket, Gryllotalpa orientalis. Sequence analysis of a 442-bp cDNA clone showed it to contain an open reading frame of 68 amino acid residues consisted of 204-bp. The homologues of the gene were found in the GenBank database in a diverse organism including insect, mammals, fungi, and plants. The deduced amino acid sequence of Sec61p ${\gamma}$ subunit homologue of the mole cricket showed the highest homology to the gene of the singly known insect, Drosophila melanogester (93% identity), and the least homology to that of the baker's yeast, Saccharomyces cerevisiae (37.2%). Phylogenetic analysis also confirmed a close relationship between the insect Sec61p ${\gamma}$ subunit homologues of G. orientalis and D. melanogester. Hydropathy analysis of the cricket mole and published other data suggested that the hydrophobic segment close to C-terminus is predicted to be the putative membrane anchor, Multiple alignment of the Sec61p ${\gamma}$ subunit homologue among several organisms showed the presence of several conserved domains including the conserved proline at position 28.