High water temperature impairs ovarian activity and gene expression in the brain–pituitary–gonadal axis in female red seabream during the spawning season

2013 ◽  
Vol 194 ◽  
pp. 24-30 ◽  
Author(s):  
Koichi Okuzawa ◽  
Koichiro Gen
Keyword(s):  
Gene Expression ◽  
Water Temperature ◽  
High Water ◽  
Spawning Season ◽  
Ovarian Activity ◽  
High Water Temperature ◽  
Red Seabream ◽  
The Brain

Effect of high water temperature on brain-pituitary-gonad axis of the red seabream during its spawning season

2003 ◽  
Vol 28 (1-4) ◽  
pp. 439-440 ◽  
Author(s):  
Koichi Okuzawa ◽  
Naoki Kumakura ◽  
Koichiro Gen ◽  
Sonoko Yamaguchi ◽  
Bong-Soo Lim ◽  
...  
Keyword(s):  
Water Temperature ◽  
High Water ◽  
Spawning Season ◽  
High Water Temperature ◽  
Red Seabream

scholarly journals Suppression of P450 aromatase gene expression in sex-reversed males produced by rearing genetically female larvae at a high water temperature during a period of sex differentiation in the Japanese flounder (Paralichthys olivaceus)

1999 ◽  
Vol 23 (2) ◽  
pp. 167-176 ◽  
Author(s):  
T Kitano ◽  
K Takamune ◽  
T Kobayashi ◽  
Y Nagahama ◽  
SI Abe
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Water Temperature ◽  
Sex Differentiation ◽  
High Water ◽  
Japanese Flounder ◽  
Female Group ◽  
High Water Temperature ◽  
Male Group

The phenotypic sex of many teleost fishes including flounders can be experimentally altered by treating embryos or larvae with varied temperatures or sex-steroid hormones. To analyse the sex determination mechanism, especially the role of cytochrome P450 aromatase (P450arom), an enzyme that catalyses the conversion of androgens to estrogens, in temperature-dependent gonadal sex differentiation in the Japanese flounder, we generated two populations of larvae, both having XX (genetic females) but each growing up to display all phenotypic females or males, by rearing the larvae at normal (18 degrees C) or high (27 degrees C) water temperatures from days 30 to 100 after hatching respectively. The larvae (XX) were produced artificially by mating normal females (XX) with gynogenetic diploid males (XX) which had been sex-reversed to phenotypic males by 17alpha-methyltestosterone. To study the role of P450arom in sex determination in the flounder, we first isolated a P450arom cDNA containing the complete open reading frame from the ovary. RT-PCR showed that P450arom mRNA was highly expressed in the ovary and spleen but weakly in the testis and brain. Semi-quantitative analyses of P450arom mRNA in gonads during sex differentiation showed that there was no difference in the levels of P450arom mRNA between the female and male groups when the gonad was sexually indifferent (day 50 after hatching). However, after the initiation of sex differentiation (day 60), the mRNA levels increased rapidly in the female group, whereas they decreased slightly in the male group. Similarly, estradiol-17beta levels rose remarkably in the female group, yet remained constant in the male group. These results suggest that induction of sex reversal of genetically female larvae to phenotypic males by rearing them at a high water temperature caused a suppression of P450arom gene expression. Furthermore, we suggest that the maintenance of P450arom mRNA at very low levels is a prerequisite for testicular differentiation, while the increased levels are indispensable for ovarian differentiation.

scholarly journals The Monthly Variation Process of Water Temperature in Jiaozhou Bay

2019 ◽  
Vol 136 ◽  
pp. 06015
Author(s):  
Dongfang Yang ◽  
Haoyuan Ren ◽  
Dong Yang ◽  
Longlei Zhang ◽  
Haixia Li
Keyword(s):  
Water Temperature ◽  
Jiaozhou Bay ◽  
High Water ◽  
Water Bodies ◽  
Interval Length ◽  
Monthly Variation ◽  
High Water Temperature ◽  
Water Field ◽  
Variation Process ◽  
Peak Value

According to the investigation materials in the water field of Jiaozhou Bay from May to October 1980, this paper studies the water temperature of Jiaozhou Bay and the monthly variation. The results show that in each monthfrom May to October, the water temperature varies from 10.80 to 26.53 °C in the waters of Jiaozhou Bay, and the interval length of water temperature is 15.73 °C. This paper determines the changing curve of the high or low value of the water temperature ateach month and establishes the corresponding simulation equation.The high water temperature reaches a maximum of 26.53 °C in August, and the low water temperature reaches a maximum of 24.69 °C in August. In the water bodies of Jiaozhou Bay, the high or low water temperature both reaches its highest value in August. In June, the increasing rate of peak value in water temperature is the fastest, and the increasing rate of low value in water temperature is relatively fast. In October, the decreasing rate of the peak water temperature is relatively fast, and decreasing rateof the lowest value in water temperature is the fastest. From May to August, the high (low) water temperature is on the rise in Jiaozhou Bay. The high water temperature appears in the western waters of the top of bay and the western waters inside of bay mouth. The low water temperature appears in the eastern and southern waters outside of bay mouth. In September and October, the high (low) water temperature in the Jiaozhou Bay water bodies is decreasing. The high water temperature appears in the eastern and southern waters outside of bay mouth, and the low water temperature appears in the western waters of the bayhead.

scholarly journals The breeding ecology of the pipefish Nerophis lumbriciformis and its relation to latitude and water temperature

2001 ◽  
Vol 81 (6) ◽  
pp. 1031-1033 ◽  
Author(s):  
N. Monteiro ◽  
V.C. Almada ◽  
A.M. Santos ◽  
M.N. Vieira
Keyword(s):  
Water Temperature ◽  
Breeding Season ◽  
Marked Reduction ◽  
High Water ◽  
Inhibitory Effect ◽  
Breeding Ecology ◽  
High Water Temperature ◽  
Temporal Differences ◽  
Breeding Activity ◽  
Different Temperatures

The breeding season of Nerophis lumbriciformis (Pisces: Syngnathidae), has not yet been determined for the southernmost part of its range. A total of 863 individuals was examined between March 1997 and November 1999. In Portugal, the breeding season of this species occurs throughout the year, with a marked reduction during summer and autumn, whilst in Britain it occurs from May to September. Despite these temporal differences, the water temperature at which breeding takes place is similar in the two areas (13–16°C). Together with preliminary laboratory observations with animals kept at different temperatures, these data support the hypothesis that the decrease in breeding activity during summer and autumn in Portugal is due to an inhibitory effect of high water temperature.

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