• The Korean Journal of Malacology
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• v.28 no.2
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• pp.131-136
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• 2012

Growth, oxygen consumption, ammonia excretion, feeding and assimilation rate were examined from May 2010 to February 2011 in order to assess the physiological changes of Haliotis discus hannai in accordance with changes in season. The water temperature was in the range of $8-23.2^{\circ}C$ and the salinity in the range of 31.9-34.1psu during the examination period. The length of shell of Haliotis discus hannai grew from 36.3 mm to 66.1 mm in the 1 year old entities and from 60.6 mm to 66.1 mm for the 2 year old entities, while the weight of the meat increased from 3.16 g to 12.04 g and from 15.8 g to 21.5 g, respectively. The oxygen consumption and ammonia excretion rate displayed trend of increase in accordance with the increase in water temperature, while the feeding rate was high during the period from July to October. The assimilation rate was in the range of 68%-71% without significant difference between the age of the entities and seasons. SFG displayed +value throughout the year for the 1 year old entities of Haliotis discus hannai as well as for the 2 year old entities with the exception of the period of July, thereby showing that they are growing throughout the year. Therefore, there was no environmental effect including water temperature and salinity during the examination period.

• Journal of Plant Biology
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• v.34 no.4
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• pp.253-260
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• 1991

Spirodela polyrhiza and Lemna aequinoctialis often occurred at the sites of high ammonium concentration and at the sites of high nitrate concentration, respectively. We investigated the different distribution between two species in relation to the type of nitrogen sources and their concentrations. Our experiments showed that L. aequinoctialis grew faster than S. polyrhiza in nitrate media with lower than 15 mM concentration. The nitrate uptake was also faster in L. aequinoctialis than in S. polyrhiza. However, neither differences in growth nor in uptake patterns between these two species were observed in ammonium media. Glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutamate synthetase (GOGAT) activities were higher in L. aequinoctialis. In particular, nitrate reductase activity (NRA) in L. aequinoctialis was 12.1 times as high as that in S. polyrhiza. These results showed that the two species responded varyingly to the types of nitrogen sources and their concentrations. Therefore, the difference in geographic distribution between the two species appeared to reflect the interspecific differences in enzyme activities and, subsequently, nitrogen absorption abilities.

• Proceedings of the Korean Society of Grassland Science Conference
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• 2005.06a
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• pp.166-167
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.314-325
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• 2002

The effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) on plant growth and N metabolic responses were examined in perennial ryegrass plants exposed to drought-stressed or well-watered condition. Mycorrhizal inoculation improved significantly leaf water potential, dry mass and P content. Drought stress increased significantly nitrate concentration in roots where the increase was much less in AM than non-AM. Drought stress decreased the concentration of soluble proteins in non-AM shoots, whereas non-significant decline occurred in AM shoots even under drought condition. The concentrations of ammonia and proline in drought stressed non-AM plants significantly increased, while mycorrhizal inoculation lowered significantly ammonia and proline accumulation. The decrease in leaf dry weight in drought stressed-plants was significantly correlated to the increase in ammonia (p<0.01) and proline concentration (p<0.01). These results suggested that the increased P content and N assimilation by mycorrhizal inoculation may be associated with drought stress tolerance, showing the moderating effects on shoot growth inhibition and ammonia accumulation in drought stressed-plants.

• Animal Bioscience
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• v.36 no.4
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• pp.671-678
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• 2023

Objective: Previous studies isolated the thermophilic ammonium-tolerant (TAT) bacterium Bacillus sp. TAT105 that grew in composting swine manure with the assimilation of ammonium nitrogen and reduced ammonia emissions during composting. Those studies also investigated the potential for applications of TAT105 to composting. It was observed that the concentration of TAT bacteria, phylogenetically close to TAT105, increased during composting. The objectives of this study were to identify the phylogenetic placement of these TAT bacteria and investigate their distribution in various composts. Methods: The phylogenetic placement of TAT105 was examined based on the sequence of 16S ribosomal RNA gene. The genomic DNA homology between TAT105 and the type strains of bacterial species that were phylogenetically close to TAT105 were examined by DNA-DNA hybridization. Moreover, the tolerances of these strains to NH₄Cl and NaCl were analyzed using a cultivation method. Concentrations of TAT bacteria in various composts were evaluated using an agar medium specific to TAT bacteria and polymerase chain reaction followed by restriction fragment length polymorphism analysis. Results: TAT105 was most closely related to Bacillus thermolactis and Bacillus kokeshiiformis. Many variants of these species have been detected in various environments, including composts. The type strains of these species displayed TAT characteristics that were similar to those of TAT105. Among the composts examined in this study, TAT bacteria were detected at high concentrations (10⁵ to 10⁹ colony forming units per gram of dry matter) in most of the composts made from cattle manure, swine manure, bark, and excess sludge. Conclusion: TAT bacteria comprised B. thermolactis, B. kokeshiiformis, and their phylogenetically close relatives. They were considered to be adaptable to composting of some certain materials, and a favorable target for searching for strains with some useful function that could be applied to composting of these materials.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.608-619
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• 1998

The small and the large intestine of swine represent the organs that extract nutrients from feedstuffs through digestion and fermentation and that allow their absorption and incorporation into the blood circulation. Special attention is directed towards the small intestine of young pigs since the transition to a solid diet at weaning exerts major impacts on the structural and functional integrity of the small intestine. Dietary factors involved in postweaning changes of gut morphology and biochemistry such as removal of bioactive compounds in sows milk at weaning, anti-nutritional factors in weaner diets, dietary fiber and the role of voluntary feed intake will be elucidated. The microbial function of the large intestine which is carried out by a diverse population of microorganisms is dependent on substrate availability. Short chain fatty acids as main fermentation products contribute to the energy supply of the host but they are also important for the maintenance of the morphological and functional integrity of the epithelium in the colon. As a result of bacterial nitrogen assimilation in the large intestine, nitrogen is shifted from the urinary to the fecal excretion route thus saving metabolic energy to the pig because less ammonia would become available for conversion to urea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.120-126
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• 2022

The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO₄^3-; P) or potassium phosphonate (PO₃^3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.455-461
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• 2000

Abstract Spirulina platensis was grown in SWlUe waste to reduce inorganic compowlds and simultaneously produce feed resources. Spirulina platensis prefers nitrogenous compounds in Ibe order: $NH_4^{+}-N>NO_3^{-}-N>simple-N$ such as urea and simple amino acids. It even consumes $NH_4^{+}-N$ first when urea or nitrate are present. Therefore, the content of residual $NH_4^{+}-N$ in Spimlina platensis cultures can be determined by the relative extent of the following processes: (i) algal uptake and assimilation; (ii) ammonia stripping; and (iii) decomposition of urea to NH;-N by urease-positive bacteria. The removal rates of total nitrogen ffild total phosphorus were estimated as an indicator of the treatment effIciency. It was found that Spirulina platensis was able to reduce 70-93% of $P_4^{3-}-P$, 67-93% of inorganic nitrogen, 80-90% of COD, and 37-56% of organic nitrogen in various concentrations of swine waste over 12 days of batch cultivation. The removal of inorganic compounds from swine waste was mainly used for cell growth, however, the organic nitrogen removal was not related to cell growlb. A maximum cell density of 1.52 dry-g/l was maintained with a dilution rate of 0.2l/day in continuous cultivation by adding 30% swine waste. The nitrogen and phosphorus removal rates were correlated to the dilution rates. Based on the amino acid profile, the quality of the proteins in the Spirulina platensis grown in the waste was the same as that in a clean culture.ulture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.24-32
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• 2004

A mathematical model is used to investigate nitrogen dynamics in the intensive aquaculture ponds in the western coast of Korea. Parameters associated with water quality, sediments and growing of shrimp (Fenneropenaeus chinensis) are measured to calibrate the model for feeding ponds A and B and storage ponds. The model describes the fate of nitrogen including loadings of ammonia from feeds, phytoplankton assimilation, nitrification, sedimentation, volatilization and discharge. The model obtains good agreements with the measured values of TAN $(NH_4,\;NH_3),\;NO(NO_2,\;NO_3)$ and Chl (chlorophyll a). Impacts of water exchange on TAN and Chl are investigated, showing that the range of 0.01-0.2 (/day) cannot effectively reduce TAN but reduces Chl. Nitrogen in the ponds A is removed by sedimentation $66\%,$ volatilization $8\%,$ discharge of particulate and dissolved $8\%.$ The pond B shows $56\%\;and\;26\%$ of sedimentation and volatilization, respectively, to yield $10\%.$ decrease and 8c/o increase compared to those in the pond A. While the pond A has larger area (1.02:0.66 ha) and same stocking density (0.025 md./L) at the beginning of culture, the pond B obtains higher stocking density (0.0065:0.0091 md./L), longer feeding period (103:121 day) and resultant higher shrimp production (1.15:2.13 t/ha/cycle) at harvest. This is possibly due to the hydraulic characteristics driven by paddlewheels. At low ratio of the low speed area and the pond area, the rate of sedimentation is high, while the rate of gas exchange is low. Thus, the measurement and model analysis suggest that water quality and shrimp production are positively correlated with the hydraulic characteristics in the shrimp ponds.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.10a
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• pp.83-106
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• 1998

This study was conducted to investigate the probiotics(acid and bile resistance, fermentation properties, viability, cholesterol assimilation, antimicrobial activity, antimutagenicity, and immunoactivation) of the strains of bifidobacteria isolated from healthy Koreans and to investigate the effects of oral administration of Bifidobacterium longum A-2 on the fecal microflora, ${\beta}-glucuronidase$ activity, pH values, Ammonia concentration. The experimental results are summarized as follows: The probiotics were tested for 23 strains including three commer챠al strains as controls. Compared to other strains, strains of A-2 and A-9 showed more acid resistance whereas A-2, A-5, A-13, A-14, A-18 and A-22 showed excellent bile resistances. The properties of bifidobacteria during fermentation were tested. Strains of A-1, A-2, A-3, A-4, A-6, and A-23 resulted in less than pH 4.5 and titratable acidity over 0.90 after 24 hr of fermentation. When the strains of A-2 was grown with glucose, maltose, and fructooligosaccharide, the acetic acid production were higher than with sorbitol and mannitol. The storage stability of the strains of A-2 and A-22 were tesed, indicating the strain A-2 was more stable over 10 days of storage at both $4^{\circ}C$ and $20^{\circ}C$ than A-22. The strains of A-8, A-10, A-11, A-12 and A-20 assimilated more than 30% of cholesterol included in the media. The strains of A-1 and A-2 showed antimicrobial activity against Sta. aureus. The antimutagenicity of the strains were also tested, showing that the mutation was suppressed more by three strains(A-2, A-12, and A-23). In addition, strain A-5 improved immunological activity(phagocytosis, $TNF-{\alpha}$, IL-6) more than other strains. In the effects of oral administration of Bif. longum A-2, the number of fecal bifidobacteria was siginificantly increased(p<0.01) and the level of fecal ${\beta}-glucuronidase$ also was siginificantly reduced(p<0.05). However there were no siginificant differences in the level of Lαctobacilli, Enterobacteriaceae, Clostridium perfringens, pH and ammonia by the administration. The results suggested that Bif. longum A-2 may be met the criteria for probiotics culture.