• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.267-272
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• 2010

Laboratory-reared marbled flounder (Pleuronectes yokohamae) juveniles ($23.2{\pm}0.2mm$ total length; age 89 day) were sampled over a 48-h period to determine any diel patterns in RNA/DNA ratios. RNA/DNA ratios were highest during daytime periods (0800, 1100, 1400, 1700 h) and significantly reduced at night (2000, 2300, 0200, 0500 h). Findings from this study indicate a diel variation in biochemical condition and suggest that special care should be taken in designing sampling plans, including sampling time and data analysis to account for this source of variability.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.411-416
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• 2011

We investigated the nutritional status of the melania snail (Semisulcospira gottschei) using RNA/DNA ratios to evaluate the effect of feeding conditions (artificial versus natural) on the reaction times of the snails in a time course following starvation. In the short experiments (48 h), the RNA/DNA ratios of the artificial feeding groups were significantly higher than those of the natural groups. While two RNA/DNA ratio peaks were observed in the artificial food group during daytime, the natural food group showed a higher ratio at night. Under starvation conditions, the RNA content decreased whereas the DNA content was constant. The RNA/DNA ratios of the freshwater snail in both groups dramatically decreased after starvation and remained constant until the end of the experiment. We verified that the RNA/DNA ratio serves as an index of nutritional condition with respect to the effect of dietary differences. These results are important for understanding optimized aquaculture rearing conditions for this important commercial freshwater snail.

• Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.192-203
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• 2004

The effects of temperatures, starvation, and kind of foods on growth, RNA/DNA ratio and protein contents during metamorphosis and early juvenile stage of olive flounder (Paralichthys olivaceus) were examined. During metamorphosis, warm-acclimated fish showed higher RNA and DNA content than those of the cold-acclimated fish, excepting H stage (28 DAH) at which the ratio was higher at cold temperature. RNA/DNA ratio during metamorphosis showed similar values at two temperatures tested. However, after 42 DAH warm-acclimated juveniles had higher DNA content compared with cold-acclimated fish, resulted in marked decreases in RNA/DNA ratios. Higher RNA content at H stage of cold-acclimated fish was consistent with an increase in protein content. Growth of fish rearing at warm temperature was higher than those of fish at cold temperature during all experiments. In starvation experiment, contents of DNA, RNA and protein significantly decreased. Even though there were no significant differences in total length (TL) and body weight between the live mysid-fed and artificial pellet-fed fish at 35 mm TL, both RNA/DNA and protein/DNA ratios of the former group was significantly higher than those of the latter due primarily to lower DNA content of the live mysid-fed group. The results from this study suggest that temperature, starvation and kind of foods should be considered when RNA/DNA ratio applied to assessing the cultured larval and juvenile fish condition.

• Korean Journal of Animal Reproduction
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• v.26 no.1
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• pp.73-78
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• 2002

This study was conducted to investigate total protein, DNA, and RNA content in corpus luteum(CL) without and with central cavity in dairy cow. Stage of the estrous cycle of corpus luteum from slaughterhouse(CL3, days 11 to 17) was classified by method of Ireland et. al.(1980). Corpus luteum was classified into corpus luteum without(less than 2mm in diameter) and with central cavity(more than 2mm in diameter) by method of Kastelic et. al.(1990). 1 In total protein content, CL with central cavity did not differ from CL without central cavity. 2. In DNA content, CL with central cavity was significantly lower than CL without central cavity(p＜0.05). 3. In protein: DNA ratios, CL with central cavity was significantly lower than CL without central cavity(p＜0.05). 4. But in RNA content, protein:RNA and RNA:DNA ratios, CL with central cavity did not differ from CL without central cavity.

• Development and Reproduction
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• v.21 no.3
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• pp.249-257
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• 2017

In a 12-week experiment, the rock bream, Oplegnathus fasciatus, and olive flounder, Paralichthys olivaceus, were investigated to determine the effects of starvation on their physiological parameters. The protein and DNA contents of the starved fish were significantly higher than the initial values and those of the fed fish. The RNA contents and RNA/DNA ratios of the fed fish were significantly higher than those of the other groups (P<0.05). The hematocrit, hemoglobin, red blood cells (RBC), and mean corpuscular volume (MCV) of the fed rock bream were significantly higher than at baseline (P<0.05), whereas the mean corpuscular hemoglobin concentration (MCHC) of the fed fish was lower than at baseline (P<0.05). The hematocrit, hemoglobin, RBC, and MCHC of the starved group were significantly lower than the baseline values, whereas the MCV of the starved group was significantly higher than the baseline value (P<0.05). No significant difference in alanine aminotransferase was observed between the fed fish and baseline, whereas the starved fish value was significantly higher than the baseline value (P>0.05). There were no significant differences in cortisol levels. However, the glucose level in the fed group was significantly higher than the baseline level and that in the starved group was significantly lower than the baseline level (P<0.05).

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.215-223
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• 2012

The ecophysiological characteristics of the oyster Crassostrea gigas in Taean area, west coast of Korea, were investigated after main spawning season from September 2011 to January 2012 to confirm the recovery process of condition. The cupped oysters, from 4 different off-bottom culture areas were compared the gonad indices, histological analysis combined with measurement of RNA/DNA contents and ratios in gonad of each sex were undertaken. To evaluate the health condition of oyster after spawning, the RNA/DNA ratio in adductor muscle, fatness and condition index (CI) were used. The results showed that cupped oysters cultured in Uihang coastal area were different physiological aspects than other experiment areas, namely continuously decreasing RNA/DNA content and ratio in adductor muscle, lowest CI and fatness. Oysters cultured in Iwon Station 1 and 2 showed fast recovery in RNA/DNA, increase in fatness and CI during post-spawning stage until October rapidly and there after it decreased. Oysters in Shinduri showed rapidly decrease in fatness and CI until October. On the contrary to this factors, RNA/DNA ratio in adductor muscle increased as like protein until October. Partially spawning season could be observed until December in Shinduri and Iwon Station 1.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.3
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• pp.182-187
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• 2008

Nine biochemical characteristics of female Oncorhynchus keta subpopulations that migrate to three streams (Namdaechun, Myeongpachun, Oshipchun) in Gangwon, Korea, were evaluated during November 2006: aspartate aminotransferase, alanine aminotransferase, creatine kinase, triglyceride, cholesterol, glucose, hemoglobin, and urea in the blood and RNA/DNA in muscle. The three subpopulations were identical morphologically, but differed in their biochemical characteristics. The RNA/DNA ratio could be useful for distinguishing the subpopulations. RNA/DNA ratios of the Namdaechun and the Myeongpachun and Oshipchun subpopulations were $3.52{\pm}0.7$ and $2.9{\pm}0.7$ and $2.4{\pm}0.8$, respectively. The difference was statistically significant (P<0.05). By contrast, the blood parameters were somewhat ambiguous.

• Journal of Nutrition and Health
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• v.14 no.2
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• pp.105-116
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• 1981

A quantitative restriction of maternal diet without changes in quality of diet was given to the Sprague Dawley rats during the third week of gestation and lactation. Half the normal average daily intake of control group was given to deficient groups in this period. Female rats of control group were fed a commercial diet ad libitum throughout the experimental period. Dietary restriction started from birth to weaning in deficient I group and from the 15th day of gestation to weaning in deficient II group. Body and brain weight of offsprings of deficient groups were significantly lower than control group, but the ratios of brain weight to body weight in deficient groups were higher than the control group. Significant difference between deficient groups (I and II) was noticed at weaning. Brain DNA, RNA and total protein of offsprings of deficient groups were significantly lower than control group, but RNA/DNA, brain weight/DNA, and total protein/DNA show that cell number were more affected than the cell size by the maternal dietary restriction during the third week of gestation and lactation. Between the deficient groups, there was a significant difference in brain DNA and RNA, but no significant difference in total brain protein. (This research was supported in part by grant from the Ministry of Education.)

• The Plant Pathology Journal
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• v.17 no.1
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• pp.22-28
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• 2001

Barley yellow dwarf virus PAV (BYDV-PAV) has a 5.7-kb positive-sense single-stranded RNA genome that contains six open reading frames (ORFs). BYDV-PAV produces three subgenomic RNAs (sgRNAs). The largest of which encodes the coat, 17-kDa, and readthrough proteins from two initiation codons. To investigate the role of intergenic and 3'-proximal noncoding regions (NCRs) in coat protein (CP) expression and BYDV-PAV replication, a full-length infectious cDNA of the RNA genome of an Illinois isolate of BYDV-PAV was constructed downstream of the Cauliflower mosaic virus-35S promoter. Linear DNA molecules of these cDNAs were infectious, expressed the 22-kDa CP, and produced both genomic RNA sgRNAs in ratios similar to those observed in protoplasts inoculated with viral RNA. The portion of 5'NCR of sgRNA1 between ORFs 2 and 3 was not required for, but enhanced translation of CP from ORF3. Mutants containing deletions in the NCR downstream of ORF5 failed to replicate in oat protoplasts. These results indicate that an intact 3$^1$NCR is required for BYDV-PAV replication.

• ALGAE
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• v.19 no.2
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• pp.123-127
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• 2004

A more rapid and efficient method to extract RNA from Ecklonia cava Kjellman (Laminariales, Phaeophyceae) was introduced in this study. Each step of the procedure was evaluated and the optimal concentration of each chemical in the lysis solution was determined. Tissue pulverization with PVPP and β-mercaptoethanol in the lysis solution were not essential for RNA extraction of this species. The highest yield and purity of E. cava RNA were obtained by the lysis solution containing 1% CTAB, 1 M NaCl, 0.7% PVP, 10mM EDTA and 100mM Tris-Cl (pH 9.0). Approximately 8μg of RNA was obtained from 200 mg of ground tissue. The ratios of the absorbance at 260 nm and 280 nm were from 1.6 to 1.8 and those of at 230 nm and 260 nm were from 1.8 to 2.0. The extracted RNAs obtained in this study turned out to have a sufficient quality for cDNA synthesis.