In vivo effects of 17-β-estradiol on plasma immunoglobulin levels and leukocyte density in zebrafish Danio rerio

Estradiol, or 17-β-estradiol (E₂), the most potent naturally occurring estrogen, is involved in the hormone-immune system interaction in both mammals and fish. However, in vivo studies are largely limited, and little is known about whether E₂ exerts similar effects on both female and male zebrafish (Danio rerio). Here, we show exposure of both sexes of D. rerio to 20 nmol/L E₂ resulted in a significant increase in Vg1 expression, but caused little damage to the hepatocytes, suggesting that this is the optimum E₂ concentration. Also, exposure to 20 nmol/L E₂ for 20 days caused a marked increase in plasma IgM levels, but had little influence on the peripheral leukocyte density, providing the first evidence of a hormone-immune system interaction in this species.     

Effects of base analogues 5-bromouracil and 6-aminopurine on development of zebrafish Danio Rerio

Zebrafish （Danio rerio） genetic screens allow isolation of a wide array of problems in vertebrate biology. The effects of base analogues 5-bromouracil and 6-aminopurine on the development of zebrafish embryos are reported for the first time in this study. The early development of the zebrafish embryos was little affected by 5-bromouracil and 6-aminopurine, while the late development （organogenesis） was significantly impaired. Embryos exposed to 5-bromouracil mainly showed curled tail, wavy body, golden pigmentation and the mouth with protruding lower jaw. 6-aminopurine-treated embryos had defective anterior structures, curled tails and wavy body. RAPD analysis showed that the majority of 5-bromouracil-and 6-aminopurine-treated larvae and fish shared banding patterns in common with the control, suggesting that most mutagenesis induced by these agents are point mutations. However, some fish derived from 5-bromouracil-treated embryos had golden（gol） pigmentation; and RAPD analysis revealed that their band patterns differed from those of the control.Possibly, 5-bromouracil can occasionally cause relatively extensive changes in the fish genome. The results of this study may provide valuable help for detailed studies of mutagenesis.     

Expression profiles of sex-related genes in gonads of genetic male Takifugu rubripes after 17β-estradiol immersion

Estradiol treatment during early life stages of tiger puffer Takifugu rubripes induces feminization in genetic males. However, the ovaries in genetic males may revert to testes once estradiol treatment is halted.Therefore studies should investigate molecular mechanisms underlying ovary-to-testis recovery in genetic males after treatment. In the present study, tiger puffer were exposed to 10, and 100 μg/L 17 p-estradiol(E_2)from 15 to 100 days post-hatching(dph), then gonad phenotypes and expression profiles of six sex-related genes(cyp19a,foxl2, dmrtl, amh, sox9a, and sox9b) were characterized after the exposure. Results showed that both 10 and 100 μg/L E_2 induced ovarian development in genetic males at 100 dph. However, all ovaries induced by 10 μg/L E_2 first developed into intersexual gonads and subsequently reverted to testes after the exposure. As for treatment of 100 pg/L E_2, while the rest of the ovaries maintained morphological stability,percentages of intersexual gonads reached 38%-57%, and none were reverted to testes. Increased mRNA levels of cyp19 a,foxl2 and sox9b and decreased mRNA levels of dmrtl, amh, and sox9a were observed during the ovarian development in genetic males. While contrary gene expression profiles were detected during ovary-to-testis transformation. The mRNA levels of all the six genes were increased during the development of intersexual gonads. These results indicated that up-regulation of dmrtl, amh and sox9a is associated with initial ovary-to-intersexual transformation, and suppression of foxl2, cypl9a and sox9b is essential for complete ovary-to-testis recovery in genetic males. This research will help to trace the molecular processes underlying gonadal transformation in teleosts.     

Changes of serum thyroid hormone and plasma catecholamine of 16 th and 17 th Chinese Expeditioners in Antarctic environment

The serum thyroid hormone and plasma catecholamine were examined in 18 male and 2 female members of the Chinese Antarctic Expedition (who spent the 2000 or 2001 austral winter at the Great Wall Station) . The changes of serum thyroid hormone i. e. total thyroxine (TT4) and free T4 (FT4) , total triodothyronine (TT3) and freeT3 ( FT3 ) , thyroid stimulating hormone ( TSH ) and plasma catecholamine, including norepinephrine (NE) , epinephrine ( E) and dopamine ( DA ) , were investigated by Chemoluminescence Immunoassay (CLIA) and High Performance Liquid Chromatography with electrochemical detection (HPLC-ECD) . Samples were taken at different time; (1)1 day before departure to Antarctica (16th expedition 1999/12/ 09; 17th expedition 2000/12/06). (2) 1 day after returned to China after living 54 weeks in Antarctica ( 16th expedition 2000/12/25 ; 17th expedition 2001/12/25 ). Comparing the data of before departure and returned, results showed that there was a significant decrease in the contents of TT4 (P <     

Recovery of gonadal development in tiger puffer Takifugu rubripes after exposure to 17β-estradiol during early life stages

The aim of the present study was to investigate the long-term effects of 17β-estradiol(E2) exposure on gonadal development in the tiger puffer( Takifugu rubripe s), which has a genetic sex determination system of male homogametic XY-XX. Tiger puffer larvae were exposed to 1, 10 and 100 μg/L E2 from 15 to 100 days post-hatch(dph) and then maintained in clean seawater until 400 dph. Changes in sex ratio, gonadal structure and gonadosomatic index(GSI) were monitored at 100, 160, 270 and 400 dph. Sex-associated single nucleotide polymorphism(SNP) markers were used to analyze the genetic sex of samples, except those at 100 dph. Exposure had a positive effect on the conversion of genetically male gonads into phenotypically female gonads at 100 dph. However, gonads from 60% of genetic XY males in the 1-μg/L E2 group and 100% in the 10-μg/L E2 group developed intersexual gonads at 160 dph; gonads of all genetic XY males in the two treatment groups reverted to testis by 270 dph. While 38%, 57% and 44% of gonads of XY fish in the 100-μg/L E2 group reverted to intersexual gonads at 160, 270 and 400 dph, respectively, none reverted to testis after E2 treatment. In addition, E2 exposure inhibited gonadal growth of both genetic sexes, as indicated by the clear dose-dependent decrease in GSI at 270 and 400 dph. The results showed that exposure to E2 during the early life stages of tiger puffer disrupted gonadal development, but that fish recovered after migration to clean seawater. The study suggests the potential use of tiger puffer as a valuable indicator species to evaluate the effects of environmental estrogens on marine fish, thereby protecting valuable fishery resources.     

Erratum to: Recovery of gonadal development in tiger puffer Takifugu rubripes after exposure to 17β-estradiol during early life stages

Journal of Oceanology and Limnology - A mistake was found in Section 2.2. The current expression is “In each treatment group, juveniles were exposed to E2 at the set concentration for 2 h...     

The effects of co-cultivation of pearl mussels and fishes on water pollution control in middle or small sized water

Our field experiments showed that the cultivation of pearl mussels formed a new biocoene composed of filamentous algae, protozoa, porifera and coelenterate. It effectively reduced nitrogen, phosphorus,chemical oxygen demand and biochemical oxygen demand in the water by 67.3%, 73.2%, 38.1% and 15.5%,respectively, during May to September 1998 when the water eutrophication was developing. This could control water eutrophication and produce pearls, shellfish meat and shells. This is an economical and effective way to control water eutrophication by using the ultra strong filtering capability of freshwater pearl mussels.     

Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream （Sparus macrocephalus）

Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.     

Study on the Preparation and Antileukemic Activity of New Lipophilic 1-β-D-arabinofuranosylcytosine Derivatives

Cytarabine(1-β-D-arabinofuranosylcytosine, Ara-C), isolated from a Caribbean sponge species Tethyacrypta, is the first antitumor drug from a marine resource. In 1980, the US Food and Drug Administration approved this drug for the treatment of different types of leukemia. This drug has a short plasma half-life, low stability, limited bioavailability, and severe side effects. To improve stability and bioavailability, we synthesized nine novel derivatives by blocking the cytarabine metabolic sites and improving lipophilicity. The c Log P values of the newly synthesized compounds were calculated. All the synthesized compounds were more lipophilic than cytarabine, resulting in membrane permeability and bioavailability improvement. The antitumor activities against leukemia cell line HL-60 were evaluated by using the MTT assay. The bioassay results revealed that the IC_(50) values of compounds 5, 8 and 9 were 0.080, 0.090 and 0.057 μmol L~(-1), respectively, which was similar with that of cytarabine(0.056 μmol L~(-1),). In comparison, compound 4 with a phosphate group at O5' was inactive. Because phosphoester bonds are easily hydrolyzed by alkaline phosphatase and are commonly used in producing prodrug strategies, compound 4 might also be metabolized in vivo and generate compound 3 or even cytarabine through a multi-step reaction. Thus, compound 4 might be a promising compound to be developed as a prodrug.     

The effects of natural capital protection on pastoralist’s livelihood and management implication in the source region of the Yellow River, China

The interaction among different livelihood capitals is a key to generate a deeper understanding of the livelihood sustainability.In this paper,we use net income per capita(economic capital),meat and milk production per capita(physical capital),and areas of fenced pasture,livestock shelter,grassland rodent control and planted grassland(physical capital) as proxy indicators of livelihood promotion,livelihood provision,and livelihood protection respectively.By developing a correlation model between pastoralists’ livelihood protection and improvement,we found that(1) there is a statistically significant correlation between the pastoralists’ livelihood protection and promotion;(2) based on the maximum effect of pastoralists’ livelihood promotion and provision,there is a benchmark in the effect of the intervention intensity of livelihood capital(grassland resource protection) on livelihood improvement;(3) on basis of two indicators,i.e.net income per capita and meat production per capita,the reasonable scales of fenced pasture,livestock shelter and planted grassland are less than 843,860 and 46 thousand hectares(hm2) per year respectively.With the marginal effect of livelihood protection,moderately decreased areas of fenced pasture and planted grassland,and increased area of livestock shelter is a critical to ensure pastoralist’s livelihood sustainability.     

Altitudinal trends in δ~(13)C value,stomatal density and nitrogen content of Pinus tabuliformis needles on the southern slope of the middle Qinling Mountains,China

In this study,a coniferous tree species(Pinus tabuliformis Carr.) was investigated at a moderate-altitude mountainous terrain on the southern slope of the middle Qinling Mountains(QLM) to detect the trends in carbon isotope ratio( δ~(13)C),leaf nitrogen content(LNC) and stomatal density(SD) with altitude variation in northsubtropical humid mountain climate zone of China.The results showed that LNC and SD both significantly increased linearly along the altitudinal gradient ranging from 1000 to 2200 m,whereas leafδ~(13)C exhibited a significantly negative correlation with the altitude.Such a correlation pattern differs obviously from that obtained in offshore low-altitude humid environment or inland high-altitude semi-arid environment,suggesting that the pattern of increasing δ~(13)C with the altitude cannot be generalized.The negative correlation between δ ~(13)C and altitude might be attributed mainly to the strengthening of carbon isotope fractionation in plants caused by increasing precipitation with altitude.Furthermore,there was a remarkable negative correlation between leaf δ ~(13)C and LNC.One possible reason was that increasing precipitation that operates to increase isotopic discrimination with altitude overtook the LNC in determining the sign of leaf δ ~(13)C.The significant negative correlation between leaf δ ~(13)C and SD over altitudes was also found in the present study,indicating that increases in SD with altitude would reduce,rather than enhance plant δ~(13)C values.     

Altitudinal trends in δ<Superscript>13</Superscript>C value,stomatal density and nitrogen content of <Emphasis Type="Italic">Pinus tabuliformis</Emphasis> needles on the southern slope of the middle Qinling Mountains,China

In this study, a coniferous tree species (Pinus tabuliformis Carr.) was investigated at a moderate-altitude mountainous terrain on the southern slope of the middle Qinling Mountains (QLM) to detect the trends in carbon isotope ratio (δ¹³C), leaf nitrogen content (LNC) and stomatal density (SD) with altitude variation in north-subtropical humid mountain climate zone of China. The results showed that LNC and SD both significantly increased linearly along the altitudinal gradient ranging from 1000 to 2200 m, whereas leaf δ¹³C exhibited a significantly negative correlation with the altitude. Such a correlation pattern differs obviously from that obtained in offshore low-altitude humid environment or inland high-altitude semi-arid environment, suggesting that the pattern of increasing δ¹³C with the altitude cannot be generalized. The negative correlation between δ¹³C and altitude might be attributed mainly to the strengthening of carbon isotope fractionation in plants caused by increasing precipitation with altitude. Furthermore, there was a remarkable negative correlation between leaf δ¹³C and LNC. One possible reason was that increasing precipitation that operates to increase isotopic discrimination with altitude overtook the LNC in determining the sign of leaf δ¹³C. The significant negative correlation between leaf δ¹³C and SD over altitudes was also found in the present study, indicating that increases in SD with altitude would reduce, rather than enhance plant δ¹³C values.