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151.
Omolara Titilayo Akinsiku Femi Kayode Agboola Adenike Kuku Adeyinka Afolayan 《Fish physiology and biochemistry》2010,36(3):573-586
Two forms of rhodanese were purified from the liver of Clarias gariepinus Burchell, designated catfish rhodanese I (cRHD I) and rhodanese II (cRHD II), by ion-exchange chromatography on a CM-Sepharose
CL-6B column and gel filtration through a Sephadex G-75 column. The apparent molecular weight obtained for cRHD I and cRHD
II was 34,500 ± 707 and 36,800 ± 283 Da, respectively. The subunit molecular weight determined by sodium dodecyl sulphate–polyacrylamide
gel electrophoresis was 33,200 ± 283 and 35,100 ± 141 Da for cRHD I and cRHD II, respectively. Atomic absorption spectrophotometric
analysis revealed that cRHD II contained a high level of iron (Fe), which presumably was responsible for the brownish colour
of the preparation. In contrast, no Fe was identified in cRHD I, and its preparation was colourless. Further characterization
of cRHD II gave true Michaelis–Menten constant (K
m) values of 25.40 ± 1.70 and 18.60 ± 1.68 mM for KCN and Na2S2O3, respectively, an optimum pH of 6.5 and an optimum temperature of 40°C. The Arrhenius plot of the effects of temperature
on the reaction rate consisted of two linear segments with a break occurring at 40°C. The apparent activation energy values
from these slopes were 7.3 and 72.9 kcal/mol. Inhibition studies on the cRHD II enzyme showed that the activity of the enzyme
was not affected by Mn2+, Co2+, Sn2+, Ni2+ and NH4
+, but Zn2+ inhibited the enzyme considerably. 相似文献
152.
Changsheng Chen Chaotian Xie Dehua Ji Yan Liang Lingmin Zhao 《Aquaculture International》2010,18(6):1045-1060
To select a reliable and sensitive method for discriminating strains of Porphyra haitanensis, the nucleotide sequence of the internal transcribed spacer 1 to internal transcribed spacer 2 regions (ITS-5.8S) of nuclear ribosomal DNA and the intergenic spacer region of RUBISCO were compared in five wild and five cultivated Porphyra haitanensis strains. Based on molecular analyses, sequences of ITS-5.8S (about 1,210 bp) could be divided into three regions: ITS1, 5.8S, and ITS2. The ITS1 and ITS2 sequences of each strain differed, even between individuals collected from the same site. In contrast, 5.8S rDNA and RUBISCO spacer sequences were identical among the ten P. haitanensis strains, although differences were found among different Porphyra species. Phylogenetic analysis also supported these conclusions. These sequence features of highly conserved regions and diversified regions that occurred repeatedly in ITS-5.8S could be useful in discriminating germplasm of P. haitanensis strains or Porphyra species. In contrast, the RUBISCO spacer is only suitable for identifying Porphyra species. New coupled primers were designed to amplify only the 5.8S rDNA and ITS2 region of Porphyra. The sequences of these amplified fragments can be readily used to identify germplasm or to perform phylogenetic analysis of Porphyra spp. 相似文献
153.
Within the framework of a larger project aimed to assess the potential of second generation hybrid striped bass for German
aquaculture the genotypic segregation of five microsatellite loci was analysed in two progeny lots (n = 74 and 76, respectively). There was no consistent correlation between microsatellite genotypes and phenotypic category
(white bass, hybrid, or striped bass). None of the individuals expressed neither only white bass nor only striped bass genotypes
at all five loci. On the other hand, only hybrid genotypes at all five loci were detected in three individuals of lot 1 and
four individuals of lot 2. Single loci tests for conformity of microsatellite genotypic segregation with Mendelian rules revealed
significant deviations (P < 0.05) in four cases for lot 1 and in three cases for lot 2. If pooled over all five loci, both lots displayed highly significant
deviations (P < 0.01) with an excess of hybrid genotypes and a deficiency of white bass genotypes. It is concluded that stabilizing selection
performed on hybrid genotypes might be a suitable approach for practical aquaculture in Europe if the goal is to become independent
of first generation hybrid fry supply and/or if establishing domesticated brood stocks of both parental species is impossible.
However, more detailed studies on the characteristics and performance of multiple hybrid generations are needed. 相似文献
154.
With the aim of improving artificial androgenesis in teleost fishes, we tested two methods for producing androgenetic diploids
of amago salmon (Oncorhynchus masou ishikawae), namely, fertilization of gamma-ray irradiated eggs with fused spermatozoa (sperm-fusion method) and the fertilization of
irradiated eggs with untreated sperm followed by the blocking of cell division (mitosis-inhibition method). Our results showed
that the optimal condition for sperm fusion was to treat the sperm with 50% polyethylene glycol (molecular weight 7500) for
100 s. The efficiency of the two methods of androgenesis was compared in terms of fertilization rate, hatching rate, and larval
survival after hatching. The rate of fertilization was lower with the sperm-fusion method than with the mitosis-inhibition
method, but the reverse was true for the hatching rate. The survival rate of hatched larvae was the same with the two methods.
Androgenesis was confirmed with a recessive albino color marker, and all viable offspring were found to be heterozygous based
on analysis of the microsatellite markers. Our results suggest that androgenesis with the sperm-fusion method is a promising
approach with potential applications in both aquaculture breeding programs and the preservation of endangered freshwater fishes. 相似文献
155.
Marcelino Herrera Ismael Hachero-Cruzado Catarina Oliveira José F. Ferrer José M. Márquez Montserrat Rosano Jose I. Navas 《Aquaculture International》2010,18(3):475-485
The weaning phase can be decisive in fish-culture viability. In this work, the relationship between the initial size and weaning
success has been studied in wedge sole (Dicologoglossa cuneata). For each age (30, 50, and 70 days after hatching, DAH), two to three sizes were selected, and all were put on the same
feeding schedule for 20 days. Each batch (three replicates) was sampled at 1, 10, and 20 days. Specific growth rate (SGR)
and survival were compared at the end of the co-feeding period, after 10 days on dry feed only. The best results for survival
and growth were found with the smallest larvae, and vice versa. The SGRs and survival rates recorded during the co-feeding
period were higher (0.8–15.6 day−1 and 68.3–97.8%) than those from the dry-food phase (0.9–4.7 day−1 and 56.3–66.7%). Successful weaning (survival = 65% and SGR = 9.3 day−1) is possible with 30 DAH larvae (7.6–8.1 mm and 3.9–4.6 mg). In conclusion, the most effective weaning would be possible
at 30 DAH, implying significant Artemia savings (25–50%). 相似文献
156.
The purpoase of this research was to test the effects of three culture densities on the growth and survival of Octopus vulgaris. A total of 141 sub-adult octopuses (1,175.4 ± 194.9 g) were randomly distributed in nine tanks of 2,000 l each (3.6 m × 1.1 m,
and 50 cm water depth). Three tanks were stocked with a low initial density of 4 kg/m3, while three other tanks were stocked with an initial density of 8 kg/m3, and the remaining three tanks were stocked at an initial density of 15 kg/m3. Octopuses were all fed frozen squid (Loligo gahi) at 5% body weight per day (%BW/day). The experiment lasted for 70 days. Water temperature varied between 20 ± 2°C, and salinity
varied between 36 ± 1 ppt. During the entire experiment, dissolved oxygen was always >75%, and ammonia was always lower than
0.1 mg/l. No differences in growth or growth rates (between 0.9 and 1.1%BW/day for the three densities) were found. Nevertheless,
mortality was significantly lower for the low density compared to the other two densities tested. Maximum densities in the
culture tanks (>25 kg/m3) were attained in the higher culture densities after 56 days of the experiment. 相似文献
157.
Maria Rowena R. Romana-Eguia Minoru Ikeda Zubaida U. Basiao Nobuhiko Taniguchi 《Aquaculture International》2010,18(6):1205-1221
Growth of several genetically improved Nile tilapia (GIFT or Genetically Improved Farmed Tilapia, FaST or Freshwater Aquaculture
Center Selected Tilapia, SEAFDEC-selected) and domesticated red tilapia (BFS or Binangonan Freshwater Station, NIFI-red or
National Inland Fisheries Institute red, HL or Hacienda Luisita) stocks were compared in controlled (tank) and uncontrolled
farm conditions (lake-based cages) with unselected NIFI or Chitralada Nile tilapia as control. Specific growth rate differed
significantly (P = 0.009) in tank-reared Nile tilapia stocks where GIFT grew best at 1.358%/day followed by FaST (1.307%/day), control stock
NIFI (1.257%/day) and SEAFDEC-selected (1.202%/day). Genetic effect explained 84.4% of the variance in growth of Nile tilapia
in tanks. Although Nile tilapia growth in cages followed the same trend where GIFT grew best at 1.570%/day, no significant
stock differences (P = 0.479) were noted. Meanwhile, red tilapia reared in either tanks or cages showed no significant stock differences in terms
of growth. However, survival of the red tilapia stocks in cages differed significantly with HL having the highest percentage
survival at 93.3%. The different growth responses of the Nile tilapia stocks especially under controlled (tank) farm conditions
were largely due to genetic factors (stock differences).Under uncontrolled farm conditions, environmental factors were generally
observed to have also affected the survival and to some extent, the growth of Asian Nile and red tilapia stocks. 相似文献
158.
The effect of trawling on fish size and on different quality parameters of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) was evaluated after conducting 16 valid hauls using two trawls in a double rig fitted with a traditional and a novel ‘T90’
codend, respectively. The total catch volume during the fishing period was 47.6 metric tons, with an average catch per codend
of 1.5 (range 0.5–2.9) tons. The mean haul duration was 5 h. The catch was assessed according to fish size, mortality, external
damage, initial white muscle pH and development of rigor mortis. Fillet quality (colour, blood spots, gaping) was assessed
after 1 week of freeze-storage. Our results showed there was no difference between the two types of nets in terms of catch
volume, but significantly slightly bigger fish were caught with T90 than with the traditional trawl net (p < 0.05). Haddock caught with the traditional trawl net had more external injuries related to the trawl gear than haddock
caught with the T90 gear (p < 0.05). The gaping frequency for cod caught with the traditional trawl net tended to be higher than cod caught with the
T90 gear, but the difference was not significant (p = 0.07). No other differences in fish quality between fish caught in the trawl nets were observed. 相似文献
159.
The relative efficacies of three natural estrogens viz., estrone (E1), estradiol-17β (E2) and estriol (E3) to induce synthesis of vitellogenin (Vg) and choriogenin (Chg) were assessed in primary hepatocyte cultures of the Indian
freshwater spotted snakehead, Channa punctata. Hepatocytes were isolated from the spotted snakehead liver by a non-enzymatic protocol. Optimum culture conditions were
standardized for ensuring their viability and functioning. Isolated hepatocytes were cultured for 48 h for monolayer formation
and then exposed to various concentrations (0.001–10 μM) of the three estrogens. Competitive homologous ELISAs, developed
and validated for spotted snakehead Vg and Chg were employed to determine the amounts of these two proteins secreted into
the culture medium after 48 h of incubation. The results reveal that although all the three estrogens were effective in inducing
the production of Vg and Chg in a dose-dependent manner, there were differences in their relative potencies. Of three estrogens,
E1 was the least potent and could induce synthesis of Vg and Chg only at a minimum concentration of 0.5 μM; whereas significant
levels of both the proteins were quantified in culture medium by exposing the hepatocytes to E2 or E3 even at a concentration of 0.001 μM. All three estrogens were effective in inducing synthesis of Vg and Chg in vivo also.
These results suggest the possibility of employing the above in vitro experimental design to monitor the presence of estrogens/estrogen-like
chemicals in natural waters, which could interfere with the estrogen receptor system of fish. This study further points to
the possibility of using Chg, in addition to Vg, as a parameter for screening various chemicals for their estrogenic activity. 相似文献
160.
Ruilong Wang Yun Gao Lihong Zhang Yike Zhang Zhanqiang Fang Jianguo He Weimin Zhang Guangzhi Ma 《Fish physiology and biochemistry》2010,36(2):157-164
Vitellogenins (Vtgs), the precursors for the yolk proteins, are very important for the embryonic development of teleosts,
and have also been studied extensively as biomarkers for environmental estrogenic mimics. The cDNA for a Vtg was isolated
from the liver of the female white cloud mountain minnow (Tanichthys albonubes) by 3′- and 5′-RACE methods. It is 4,171 bp in full length, and encodes a putative protein of 1,326 amino acids. This putative
Vtg, designated as wcmmVtg, contains complete portions of LVI and PV, but lacks the C-terminal half of LVII and thus belongs
to type I vitellogenin. In addition to the liver of the female fish, wcmmVtg was also shown to be expressed in the ovary.
During ovarian development, the mRNA expression of wcmmVtg in both the liver and ovary was continuously increased from the
previtellogenic to late vitellogenic stages, but then decreased significantly at post-spawning stage. In the male fish, expression
of wcmmVtg mRNA was induced in the liver by treatment with E2 (10 and 100 ng/l) for 14 days. These results suggest that the Vtg originated from the ovary of the white cloud mountain minnow
may also contribute to the accumulation of yolk proteins during oocyte growth, and that the male white cloud mountain minnow
is sensitive to the estrogenic treatment in terms of Vtg mRNA expression, which could also be applied to monitor the environmental
estrogenic mimics. 相似文献