• Journal of Environmental Impact Assessment
• /
• v.21 no.5
• /
• pp.707-713
• /
• 2012

There are a lot of parameters affecting microbial acclimation/cultivation characteristics such as dynamic conditions, F/M ratio and substrate affinity. From the process control point of view, the effect of high salinity on the removal efficiencies of BOD and SS have been documented by few researchers. In this research, lab-scale CAS(Conventional Activated Sludge) process and modified $A_2O$(Anaerobic/Anoxic/Oxic) process were operated and monitored to evaluate the characteristics of microbial acclimation and cultivation under high salinity wastewater during the period of three weeks. As a result of acute microbial activity test(6hr) at various $Cl^-$ concentration, the appropriate $Cl^-$ concentration for microbial growth and acclimation ranged under 3,100 mg/l. As a result of acclimation/cultivation test, the trend of COD removal efficiency reduced gradually as time elapsed. It is considered that $NH_4$-N removal phenomenon of the conventional pollutants removal mechanisms gave little effect to the microbial acclimation/cultivation under high salinity wastewater.

• Journal of Sericultural and Entomological Science
• /
• v.40 no.2
• /
• pp.91-96
• /
• 1998

In relation to cold acclimation, this experiment was carried out to understand the changes of the cortical cells in the living barks of the mulberry during wintering period. The living barks of three mulberry varieties(Kaeryangppong, Shinilppong and Yongcheonppong) were sampled from December, 1995 to March, 1996. The result of this experiment was summarized as follows. The cortical cells in the living barks of the mulberry in December were filled with small vacuoles. Plastids and mitochondrias were located near the nucleus. At this time, almost all starch granules disappeared from the plastids. In January and February, mitochondria, palstids and microbodys of the cortical cell were observed. As increasing temperature from March, dictysomes and polysomes were sparse. Again, starch granules disappeared were observed in the plastids. From the above result. starch granules in plastide of the cortical cell of the mulberry disappeared during cold acclimation stage. After late January, Proplastid was observed in the cortical cell and the ultrastructures of cortical cell were actively changed.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.6
• /
• pp.753-758
• /
• 2011

The seawater adaptability of land-locked masu salmon Oncorhynchus masou masou via acclimation was examined for aquaculture purposes. The survival, blood chemistry, and histological changes of masu salmon (150 g) were measured after 7-, 15-, and 30-day acclimation periods. After a total of 60 days in seawater cultures that incorporated the various acclimation periods, survival was 83.5, 87.2, and 91.0% for the 7-, 15-, and 30-day periods, respectively; thus, survival increased with longer periods of acclimation. Feeding efficiencies were 32.1, 52.0, and 40.6% for the 7-, 15-, and 30-day periods, and specific growth rates were 0.14, 0.26, and 0.23%, respectively. Generally, masu salmon appeared to exhibit better growth performance after an acclimation period of 15 days. Cortisol concentrations [mean ${\pm}$ SD] for 7, 15, and 30 days of acclimation were $21.0{\pm}6.5$, $17.8{\pm}4.8$, and $21.2{\pm}5.4\;{\mu}g/dl$, with the lowest values occurring with 15 days of acclimation. Osmolarities were $359.2{\pm}26.1$, $350.4{\pm}29.2$, and $354.6{\pm}29.3$ mOsm/kg, and glucose concentrations were $60.7{\pm}20.7$, $72.9{\pm}17.3$, and $76.6{\pm}14.1$ mg/dl for the 7-, 15-, and 30-day acclimation periods, respectively (P < 0.05). The histological study revealed that both gills and both kidneys of the masu salmon exhibited middle- to end-stage and middle-stage lesions in the 7- and 15-day groups, respectively, whereas these organs only had early-stage lesions in the 30-day group in the final experiment. Therefore, the seawater acclimation of masu salmon should involve more than 30 days in seawater.

• Korean Journal of Microbiology
• /
• v.34 no.3
• /
• pp.96-100
• /
• 1998

The effects of electron acceptors and acclimation of inoculum on the anaerobic degradation of benzene, toluene, and m-xylene (BTX) were investigated to enhance the rate of degradation by estuarine sediment inoculum. With the fresh sediment inocula, degradation of BTX ensued after a 10-week acclimation period, and 37~61% of benzene and 57~61% of toluene were degraded after 16 weeks. Sediments from heavily contaminated sites showed higher degradation rates of BTX. After a 6-month of acclimation, degradation onset rapidly from the time of BTX addition and no difference was found among the sediment inocula. Single compound of BTX was slowly degraded in the methanogenic conditions, however, the degradation of BTX mixture was slow in the denitrifying conditions. Although the degradation rate of m-xylene was the fastest among the components of BTX mixture, longer acclimation enhanced the degradation rate of BTX, especially that of benzene. When the culture fluids were tested with Microtox, anaerobic degradation of BTX reduced the toxicity of BTX as well.

• ALGAE
• /
• v.39 no.1
• /
• pp.17-30
• /
• 2024

Red macroalga Pyropia yezoensis is a high valuable cultivated marine crop. Its acclimation to cold stress is especially important for long cultivation period across winter in coasts of warm temperate zone in East Asia. In this study, the response of P. yezoensis thalli to low temperature was analyzed on physiology and transcriptome level, to explore its acclimation mechanism to cold stress. The results showed that the practical photosynthesis activity (indicated by Φ_PSII and qP) was depressed and pigment allophycocyanin content was decreased during the cold stress of 48 h. However, the F_v/F_m and non-photochemical quenching increased significantly after 24 h, and the average growth rate of thalli also rebounded from 24 to 48 h, indicating a certain extent of acclimation to cold stress. On transcriptionally, the low temperature promoted the expression of differentially expressed genes (DEGs) related to carbohydrate metabolism and energy metabolism, while genes related to photosynthetic system were depressed. The increased expression of DEGs involved in ribosomal biogenesis and lipid metabolism which could accelerate protein synthesis and enhance the degree of fatty acid unsaturation, might help P. yezoensis thallus cells to cope with cold stress. Further co-expression network analysis revealed differential expression trends along with stress time, and corresponding hub genes play important roles in the systemic acquired acclimation to cold stress. This study provides basic mechanisms of P. yezoensis acclimation to cold temperature and may aid in exploration of functional genes for genetic breeding of economic macroalgae.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.590-593
• /
• 2001

The effect of salinity on the nitrification efficiency of the nitrifier consortium was evaluated for the nitrification of saline wastewater. The nitrifier consortium, which was the activated sludge acclimated with ammonium as the only energy source, was used as the nitrifier for the salt acclimation. Airlift reactors for the nitrification of ammonia with increasing concentration in saline synthetic wastewater (35 g/I NaCD, and synthetic wastewater without salt as a control, were continuously operated with the nitrifier consortium for 43 days. The ammonia removal rate was about 23g ammonia-N/$m^3$/day in both the absence and presence of the salt. An accumulation of nitrite was observed in the saline nitrification reactor at an early period. However, the nitrite decreased to less than 1 mg/l after 39 days of operation. The salinity increased the acclimation time of the nitrifier consortium to obtain a stable marine nitrification system. However, the salt acclimated system showed the efficient removal of ammonia which was same as that without salt.

• Ocean and Polar Research
• /
• v.26 no.3
• /
• pp.433-438
• /
• 2004

Stress response to the seawater acclimation in coho salmon (Oncorhynchus kisutch) smolt was investigated. Salt concentration of rearing water was gradually increased for 3 days from freshwater to seawater (30 ppt salt level). The changes of serum concentrations of cortisol as a primary stress indicator, and as secondary indicators, glucose (GLC), lactate (LAC), triglyce.ide (TG), cholesterol (CHOL), sodium ion $(Na^+)$, chloride ion $(Cl^-)$ and enzyme activities (alanine aminotransferase, ALT: aspartate aminotrasferase, AST; lactate dehydrogenase, LDH) were quantified during the acclimation experiment. Among them, cortisol, LAC, TG, CHOL, ALT, AST concentrations showed rapid increase at the first exposure to the 10ppt salt level (day 1), and began to decrease to the constant values after day 2 of adaptation at 20ppt salt level. However, LDH concentration tended to decrease during the whole experimental period. $Na^+\;and\;Cl^-$ showed slight decrease at day 1, and increased to a little bit higher values after day 2 rather than those in freshwater. All the fishes started on taking a food after day 4 of seawater adaptation. From these results, to reduce osmotic shock inducible stress to fish in seawater acclimation, gradual increase of salt levels is recommended.

• Journal of fish pathology
• /
• v.8 no.2
• /
• pp.111-118
• /
• 1995

This experiment was carried out in order to elucidate the effect of NaCl(0.85%) acclimation on congestion symptoms in central venous sinuses(CVS) of gill filaments and on the alteration of blood constituents in cultured eels for 1, 2, 3, 4, 5, 6 and 7days after handling stress. After giving a handling stress on eels, the frequency of gill congestion was about 90%. It gradually decreased to 40% on the 3rd day, then increased to 60% on the 7th day in NaCl(0.85%) acclimation. The values of haematocrit(Ht), methemoglobin(Met-Hb), glucose (GLU), calcium($Ca^{++}$), lactic dehydrogenase(LDH), glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase(GOT) were lower than those of the control, whereas magnesium($Mg^{++}$) and haemoglobin(Hb) were higher than the control. However total protein(Tp) and albumin (ALB) levels similar to the control. When the fish after giving a handling stress were cultured in NaCl-free water as a control, the frequency of gill congestion and the value of blood components showed a similar pattern to that obtained from the NaCl acclimated experiments. However, in the early period(1-3day) after handling stress, NaCl acclimating slightly helped the natural tendancy of recovery. These results suggest that the frequency of gill congestion is not always reduced over the whole period of NaCl acclimation. However, the acclimation to NaCl solution may be a somewhat useful therapy for the gill congestion in stressed eels.

• The Korean Journal of Zoology
• /
• v.29 no.2
• /
• pp.107-120
• /
• 1986

The activities of serum of serum lactate dehydrogenase (SLDH), serum alkaline phosphatase (SALP), serum creatine phosphokinase (SCPK), and their isozymes were determined in adult male Sprague-Dawley rats acclimated to cold environment $(4\\pm1^\\circC)$ for 36 days. The SLDH activity was significantly higher in the early stage of acclimated period. The steady state of SLDH activity seemed to be reached by the end of acclimated period. Electrophoretic separation of serum of control rat showed three SLDH isozymes. Isozymes SLDH4 and SLDH5 appeared most prominently, whereas only trace of SLDH1 or SLDH2 was found. The increase in SLDH level during acclimation to cold environment is a reflection of an immediate increase in the SLDH1, SLDH2, and SLDH3 type of SLDH isozyme. The acclimation to cold environment increased significantly level of SALP in the early state of acclimated period. SALP activity showed a attaining steady state with the resting level after transient rise. Electrophoretic separation of SALP of control rats showed the SALP1 and SALP2 fractions. The transient rise in SALP activity of rats acclimated to cold environment coincided with a transient rise in SALP1 fraction. Immediately after exposure to cold environment, there was significant elevation in SCPK activity. Value returned to normal after transient rise. A new steady state of SCPK activity seemed to be reached by 36 days. It may be inferred from the above data that thermal compensation appears to result from a change in the activity of an enzyme and that the SLDH, SLDH-isozyme, SALP-isozyme, and SCPK may be involved directly or indirectly in thermoregulation during acclimation to cold environment.

• Korean Journal of Environmental Biology
• /
• v.36 no.3
• /
• pp.377-384
• /
• 2018

This study focused on the effects of feeding on postlarvae of shrimp, Litopenaeus vannamei, during the identified acclimation time to low salinity. A total of 5 different salinity groups with or without feeding (32, 24, 16, 8, and 2 psu, 1 liter, triplicates) were prepared, and 30 shrimp were settled at PL21 (postlarvae) and placed in each group. After 24 hours of the experimentation process, the survival rate of the fed and starved groups was observed to be lower in the 2 psu group compared to other salinity groups, with the rate of 86.6% and 81.1%, respectively. The condition index of glucose and triglyceride, which are important factors for osmoregulation and as energy sources, was 4.2-7.6 times and 2.7-3.4 times higher in the fed groups than the starved groups at all the levels of salinities. The creatine level increased by 1.1-1.5 times in the starved groups as compared to the fed groups. Likewise, the activity of all the digestive enzymes like, lipase, ${\alpha}$-amylase, trypsin, and alkaline protease were clearly higher in the fed groups (ANOVA, p<0.05). Apparently, it was observed that feeding is effective for the postlarvae of shrimp, which shows a characteristic fast metabolism and larval development, during the acclimation period to low salinity.