• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.206-212
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• 1998

This study was undertaken to explore the applicability of glutathione S-transferase (GST) activity as a predictable indicator to monitor chemical pollution in shells and fishes utilized for food. There were some variations in the basal level of GST activity depending on species tested. Ark shells, Anadara satowi, showed the highest normal enzyme activity, followed by catfish and marine mussels, Mytilus coruscus. White clams, Meretrix lusoria, Israeli carp and catfish had lower activity. When A. satowi was exposed to 3-methyl-cholanthrene (3-MC), a prototypic polycyclic aromatic hydrocarbon for 1 week, GST activity decreased by about 30%. This reduction in GST activity induced by 3-MC did not recover until two weeks after the cessation of exposure. GST activity increased in response to 3-MC in most of the other species studied. The GST elevation in M. coruscus attained its maxinum of about 200% at the termination of 3-MC exposure maintaining this level up to 2 weeks, and declined gradually thereafter. 3-MC also induced GST activity in lsraeli carp in a similar fashion to M. coruscus. Phenobarbital induced GST activity both in M. coruscus and lsraeil carp. Other chemicals. such as clofibrate, butylated hydroxyanisole. hexachlorobenzene, and oxolinic acid did not change the enzyme activity significantly in most speciel. Phenol depressed GST activity only in lsraeli carp. These results suggest that the basal level of GST activity is somewhat variable and that the direction of change in response to chemicals seems to be related to its normal activity. The change in enzyme activity can be a preditable indicator of some environmental chemicals such as PAHs and phenol.

• The Korean Journal of Zoology
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• v.27 no.2
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• pp.85-92
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• 1984

The effect of copper ion on the lactate dehydrogenase isozyme patterns in the heart, liver, kidney, skeletal muscle, and ovary of catfish, Parasilurus asotus, was studied by cellulose acetate gel electrophoresis. 1. The LDH-1 and LDH-2 of heart type appeared in the heart muscle of control fish. When the fish were exposed to copper ion, however, the LDH-1, LDH-2, LDH-3, and LDH-4 appeared. The amount of LDH-1 was decreased and those of LDH-2, LDH-3, and LDH-4 were increased. 2. There was one band of LDH-4 in the liver of normal fish. But the amount of LDH-4 was decreased and additional new LDH-5 appeared by exposure to copper ion. 3. There were LDH-1, LDH-2, and LDH-4 in the kidney tissue of both control and experimental groups. The LDH-1 was increased, whereas LDH-2 and LDH-4 were decreased after exposure to copper ion. 4. There was broad band of LDH-5 in the skeletal muscle of the control fish. However, the LDH-4 and LDH-5 with M sub-band appeared by the exposure to copper ion. 5. There was LDH-3 band only in the ovary of control, wheras all five LDH isozymes appeared in the ovary of the fish exposed to copper iion. 6. During the period of exposure to copper ion, the LDH isozyme of heart type which associated with aerobic metabolism was decreased, but the LDH isozyme of muscle type of anaerobic metabolism was increased in most of heart, liver, and skeletal muscle. It seems that these organs are related to some of important functions for anaerobic metabolism during the copper poisoning period.

• Clean Technology
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• v.19 no.3
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• pp.313-319
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• 2013

To produce biodiesel efficiently from fish oil containing 4% free fatty acid, esterification and trans-esterification were carried out with Vietnam catfish oil, which was kindly provided from GS-bio company. Heterogeneous solid acid catalysts such as Amberlyst-15 and Amberlyst BD-20 and sulfuric acid as homogeneous acid catalyst were used for the esterification of free fatty acids in the fish oil. Sulfuric acid showed the highest removal efficiency of free fatty acid and the shortest reaction time among three acid catalysts. The base catalysts for trans-esterification such as KOH, $NaOCH_3$ and NaOH were compared with each other and KOH was determined to be the best transesterification catalyst. Some solid material, which assumed to be saponified product from glycerol and biodiesel, were observed to form in the fish oil biodiesel when using $NaOCH_3$ and NaOH as the transesterification catalyst. The initial acid value of fish oil was proven to have a negative effect on biodiesel conversion. Of the three catalysts, KOH catalyst transesterification was shown to have high content of FAME and the optimal ratio of methanol/oil ratio was identified to be 9:1.

• Journal of Aquaculture
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• v.6 no.3
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• pp.221-233
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• 1993

Cell size, DNA content, chromosome and PCR-based mitochondrial 12S rRNA gene analyses were conducted to obtain basic informations for genetic stock identification of spotted flounder (Verasper variegatus) from Yeocheun, Korea. The mean erythrocytic and nuclear volumes of spotted flounder were $211.10{\mu}m^3$ and $23.03{\mu}m^3$, respectively. The haploid DNA content of this species was 0.79 pg/cell which correspond to $46.5\%$ of carp and to $22.6\%$ of mammals. Spotted flounder had the 2n = 46 acrocentric chromosomes but no heteromorphic sex chromosomes was found. Mitochondrial DNA gene for 12S ribosomal RNA was amplified by polymerase chain reaction (PCR) and the PCR products were subjected to digestion with 15 restriction endonucleases. Restriction enzyme analyses revealed that Ava I, Mae II, Sma I and Xba I had one restriction site in the mitochondrial 12S rRNA gene segment of spotted flounder, while Mae I had two. Segments of 12S rRNA gene from mitochondria in spotted flounder were sequenced and compared with channel catfish and human as controls. The 12S rRNA gene of this species was more similar to that of channel catfish than to human's.

• Journal of Life Science
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• v.14 no.4
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• pp.702-707
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• 2004

In native-polyacrylamide gel electrophoresis of Pangasius polyuranodon, the lactate dehydrogenase (EC 1.1.1.27, LDH) $A_4$, $A_3$B, $A_2$$B_2$,$AB_3$ and $B_4$ isozymes were expressed in various tissues. The LDH $A_4$ and liver-specific $C_4$ isozymes were expressed in the tissues of Hypostomus Plecostomus. The bands of LDH in skeletal muscle, heart and eye tissues were not detected while one band was detected in kidney and liver, and four bands were detected in brain. The detected one band in liver was identified as alcohol dehydrogenase and an anodal band of skeletal muscle was identified as nothing dehydrogenase. The LDH in skeletal muscle, heart and eye might function as pyruvate reductase. The degree of inhibitions of LDH in skeletal muscle and heart of P. polyuranodon by 10 mM pyruvate were measured 57.6% and 73.8%, respectively. However, those of LDH in tissues of H. plecostomus were measured 52.7-61.8% so tissue specificity did not appear. Therefore, H. ple-costomus might be more acclimated to hypoxic environment by anaerobic metabolism of LDH iso-zymes than P. polyuranodon.

• Applied Microscopy
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• v.28 no.1
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• pp.39-48
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• 1998

The spermatozoa of bagrid catfish, Pseudobagrus fulvidraco are approximately $76{\mu}m$ in length, and a relatively simple and elongated cell composed of a spherical head, a short middle piece and a tail. The ultrastructure of spermatozoa of P. fulvidraco is characterized by the following features. The acrosome is absent as in most teleost. The round nucleus measuring about $1.67{\mu}m$ in length and diameter is depressed with a deep nuclear fossa. The nuclear fossa, the length of which is about three-fifths of the nuclear diameter, contains the proximal and distal contrioles. The two centrioles are oriented approximately $160^{\circ}$ to each other. The filamentous materials give rise to satellite appendages arranged tangentially from the triplets of the distal centriole and the doublets of the anterior end of the axoneme toward the nuclear envelope. The mitochondria are not fused and their number is 20 or more. They are arranged in two or three layers and two rings within the cytoplasmic collar and surround the axoneme. They are separated from the axoneme by the cytoplasmic canal. The axoneme is of the 9+2 microtubular pattern and has inner but no outer dynein arms. The two lateral fins are in the same plane with the two central microtubules, the doublets 3 and 8, which are ultrastructural characteristics of the sperm tail unlike other siluroids lacking the lateral fins.

• Fisheries and Aquatic Sciences
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• v.21 no.2
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• pp.6.1-6.10
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• 2018

The intention of this study was to identify the bacterial pathogens infecting Oreochromis niloticus (Nile tilapia) and Clarias gariepinus (African catfish), and to establish the antibiotic susceptibility of fish bacteria in Uganda. A total of 288 fish samples from 40 fish farms (ponds, cages, and tanks) and 8 wild water sites were aseptically collected and bacteria isolated from the head kidney, liver, brain and spleen. The isolates were identified by their morphological characteristics, conventional biochemical tests and Analytical Profile Index test kits. Antibiotic susceptibility of selected bacteria was determined by the Kirby-Bauer disc diffusion method. The following well-known fish pathogens were identified at a farm prevalence of; Aeromonas hydrophila (43.8%), Aeromonas sobria (20.8%), Edwardsiella tarda (8.3%), Flavobacterium spp. (4.2%) and Streptococcus spp. (6.3%). Other bacteria with varying significance as fish pathogens were also identified including Plesiomonas shigelloides (25.0%), Chryseobacterium indoligenes (12.5%), Pseudomonas fluorescens (10.4%), Pseudomonas aeruginosa (4.2%), Pseudomonas stutzeri (2.1%), Vibrio cholerae (10.4%), Proteus spp. (6.3%), Citrobacter spp. (4.2%), Klebsiella spp. (4.2%) Serratia marcescens (4.2%), Burkholderia cepacia (2.1%), Comamonas testosteroni (8.3%) and Ralstonia picketti (2.1%). Aeromonas spp., Edwardsiella tarda and Streptococcus spp. were commonly isolated from diseased fish. Aeromonas spp. (n = 82) and Plesiomonas shigelloides (n = 73) were evaluated for antibiotic susceptibility. All isolates tested were susceptible to at-least ten (10) of the fourteen antibiotics evaluated. High levels of resistance were however expressed by all isolates to penicillin, oxacillin and ampicillin. This observed resistance is most probably intrinsic to those bacteria, suggesting minimal levels of acquired antibiotic resistance in fish bacteria from the study area. To our knowledge, this is the first study to establish the occurrence of several bacteria species infecting fish; and to determine antibiotic susceptibility of fish bacteria in Uganda. The current study provides baseline information for future reference and fish disease management in the country.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.845-853
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• 2012

To investigate the role of temperatures and photoperiods as environmental cues regulating reproductive rhythm in Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with photoperiods and water temperatures during gonadal degeneration periods. Gonadosomatic index (GSI) in control was $8.16{\pm}1.50%$, while in other experiment GSI levels in female were lower than that in the control. In case of experimental precinct of 9 light (L) and 15 L, GSI levels were decreased. But GSI level with $20^{\circ}C$ was no diffrence after 40 and 60 days. GSI level in male of control was $0.35{\pm}0.05%$. GSI under 9 L and $25^{\circ}C$ was similar to that in control, whereas its level in other experiments was lower than that in control. Testosterone (T) of female was $3.68{\pm}0.22$ ng/mL at experimental precinct. In case of 9 L and 15 L, concentration of T were lower than experimental precinct in all of water temperature. Estradiol-$17{\beta}$ ($E_2$) and $7{\alpha}$, $20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}OHP$) levels of female were $0.42{\pm}0.02$ and $0.83{\pm}0.01$ ng/mL at experimental precinct. $E_2$ levels of 9 and 15 L were higher than experimental precinct and $17{\alpha}20{\beta}OHP$ levels of 9 and 15 L were higher than experimental precinct. In case of T and 11-ketotestosterone levels were $0.69{\pm}0.11$ and $.62{\pm}0.03$ ng/mL in male. During the period of gonadal degeneration, gonadal maturation did not occur in any of the experimental regimes. However, comparatively high levels of $E_2$ observed at low temperature regimes ($20^{\circ}C$) regardless of photoperiods.

• Journal of Life Science
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• v.13 no.6
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• pp.805-813
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• 2003

cDNA encoding somatolactin (SL) was obtained by RT-PCR from pituitary glands of rock bream (Oplegnathus fasciatus). The full length cDNA of rock bream somatolactin (rbSL) is 1636 bp long. It contains a 696 bp open reading frame encoding a signal peptide of 24 amino acids (an) and a mature protein of 207 aa. rbSL has seven cysteine residues$(Cys^{5},\; Cys^{15},\; Cys^{42},\; Cys^{65},\; Cys^{181},\; Cys^{198}\; $and $Cys^{206})$ and two potential N-glycosylation sites at positions $Asn^{121}$and $Asn^{153}$. The rbSL shares 61.1∼92.6% amino acid sequence similarities and 63∼92.6% nucleotide sequence identities with other teleost SLs, except for goldfish and channel catfish SL. Amino acid sequence alignment revealed that rbSL has four conserved domains $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$ common to all SLs. Out of these domains, $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$, are also conserved in all teleost growth hormones and prolactins. The cDNA of rbSL has been cloned into pET expression vector in order to produce recombinant rbSL in E. coli BL2l(DE3) cells. The recombinant protein showed a molecular weight of 27 kDa in SDS-PAGE.

• Ecology and Resilient Infrastructure
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• v.5 no.2
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• pp.105-109
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• 2018

The main objective of this investigation was to examine oxygen consumption and ammonia excretion within cultured catfish, Silurus asotus ($22.9{\pm}0.9cm$, $100.7{\pm}11.7g$ n = 30) by noise and vibration stress in aquaculture farm. The vibration of 48, 58 and 68 dB (V) and noise of $77.6{\pm}1.8dB$ (A) from an electric vibrator was turned on for 15 minutes during each hour each day(0800-1800) for 11 days experimental period. The oxygen consumption (OC) of S. asotus the beginning of the experiment (0 day) in 58 dB group after 1, 5, 9 and 11 days was decreased 21.8, 30.2, 36.0 and 53.2%, respectively. In 68 group after 1, 7 and 11 days was decreased 22.7, 35.1 and 57.7%, respectively. The OC decreased exponentially and the relationship between them was expressed as OC = 0.374D + 90.762 ($r^2=0.048$) at 48 dB, OC = -3.581D + 89.520 ($r^2=0.831$) at 58 dB and OC = -4.109D + 90.907 ($r^2=0.884$) at 68 dB. Ammonia excretion (AE) of the beginning of the experiment in 48, 58 and 68 groups after 1 day was increased by 34.8, 51.8 and 63.2%, respectively, but it was decreased significantly from 3 to 11 days. The AE increased exponentially and the relationship between them was expressed as AE = -1.646D + 115.915 ($r^2=0.265$) at 48 dB, AE = -8.230D + 122.132 ($r^2=0.750$) at 58 dB and AE = -7.086D + 123.690 ($r^2=0.614$) at 68 dB.