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481.
To improve the expression efficiency of exogenous genes in Chlamydomonas reinhardtii, a high efficient expression vector was constructed. Green fluorescent protein (GFP) was expressed in C. reinhardtii under the control of promoters: RBCS2 and HSP70A-RBCS2. Efficiency of transformation and expression were compared between two transgenic algae: RBCS2 mediated strain Tran-Ⅰ and HSP70A-RBCS2 mediated strain Tran-Ⅱ. Results show that HSP70A-RBCS2 could improve greatly the transformation efficiency by approximately eightfold of RBCS2, and the expression efficiency of GFP in Tran-Ⅱ was at least double of that in Tran-Ⅰ. In addition, a threefold increase of GFP in Tran-Ⅱ was induced by heat shock at 40℃. All of the results demonstrated that HSP70A-RBCS2 was more efficient than RBCS2 in expressing exogenous gene in C. reinhardtii. 相似文献
482.
Five full-sib families of the Pacific oyster (Crassostrea gigas) larvae were used to study the mode of inheritance at eight microsatellite loci, and the feasibility of these markers for kinship estimate was also examined. All eight microsatellite loci were compatible with Mendelian inheritance. Neither evidence of sex-linked barriers to transmission nor evidence of major barriers to fertilization between gametes from the parents was shown. Three of the eight loci showed the presence of null alleles in four families, demonstrating the need to conduct comprehensive species-specific inheritance studies for microsatellite loci used in population genetic studies. Although the null allele heterozygotes were considered as homozygotes in the calculation of genetic distance, offspring from five full-sib families were unambiguously discriminated in the neighbor-joining dendrogram. This result indicates that the microsatellite markers may be capable of discriminating between related and unrelated oyster larvae in the absence of pedigree information, and is applicable to the investigation of the effective number of parents contributing to the hatchery population of the Pacific oyster. 相似文献
483.
The physiological responses of Nitzschia palea Kvtzing, a freshwater diatom, to elevated CO2 were investigated and compared with those of a marine diatom, Chaetoceros muelleri Lemmermann previously reported. Elevated CO2 concentration to 700 μl/L increased the dissolved inorganic carbon (D!C) and lowered the pH in the cultures of N. palea, thus enhancing the growth by 4%-20% during the whole growth period. High CO2-grown N. palea cells showed lower levels of dark respiration rates and higher Ik values. Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO2 concentration in airflow to the bottom of cultures, although the doubling CO2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters. N. palea cells were found to be capable of using HCO5 in addition to gaseous CO2, and the CO2 enrichment decreased their affinity for HCO5 and CO2. Although doubled CO2 level would enhance the biomass of N. patea and C. muelleri to different extents, compared with the marine diatom, it had a significant effect on the specific growth rates of N. palea. In addition, the responses of photosynthetic parameters of IV. palea to doubled CO2 concentration were almost opposite to those of C. muelleri. 相似文献
484.
In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying
forcing field to study the barrier layer (BL) in the PN section in the East China Sea (ECS). The BL can be found along the
PN section with obviously seasonal variability. In winter, spring and autumn, the BL occurs around the slope where the cold
shelf water meets with the warm Kuroshio water. In summer, the BL can also be found in the shelf area near salinity front
of the Changjiang (Yangtze) River Dilution Water (YRDW). Seasonal variations of BL in the PN section are caused by local hydrological
characteristics and seasonal variations of atmospheric forcing. Strong vertical convection caused by sea surface cooling thickens
the BL in winter and spring in the slope area. Due to the large discharge of Changjiang River in summer, the BL occurs extensively
in the shelf region where the fresh YRDW and the salty bottom water meet and form a strong halocline above the seasonal thermocline.
The formation mechanism of BL in the PN section can be explained by the vertical shear of different water masses, which is
called the advection mechanism. The interannual variation of BL in summer is greatly affected by the YRDW. In the larger YRDW
year (such as 1998), a shallow but much thicker BL existed on the shelf area.
Supported by National Basic Research Program of China (973 Program, No. 2005CB422303 and 2007CB411804), the Key Project of
the International Science and Technology Cooperation Program of China (No. 2006DFB21250), the “111 Project” of the Ministry
of Education (No. B07036), the Program for New Century Excellent Talents in University, China (No. NECT-07-0781) 相似文献
485.
To investigate the antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo, six bromophenol derivatives 6-(2,3-dibromo-4,5-dihydroxybenzyl)-2,3-dibromo-4,5-dihydroxy benzyl methyl ether (1), (+)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroisobenzofuran (2), 3-bromo-4-(2,3-dibromo-4,5-dihydroxybenzyl)-5-methoxymethyl-pyrocatechol (3), 2,2′,3,3′-tetrabromo-4,4′,5,5′-tetrahydroxy-diphenylmethane (4), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (5), 2,2′,3-tribromo-3′,4,4′,5-tetrahydroxy-6′-ethyloxymethyldiphenylmethane (6) were isolated from brown alga Leathesia nana, and their cytotoxicity were tested by MTT assays in human cancer cell lines A549, BGC-823, MCF-7, B16-BL6, HT-1080, A2780,
Bel7402 and HCT-8. Their inhibitory activity against protein tyrosine kinase (PTK) with over-expression of c-kit was analyzed also by ELISA. The antitumor activity of ethanolic extraction of Leathesia nana (EELN) was evaluated on S180-bearing mice. All compounds showed very potent cytotoxicity against all of the eight cancer cell lines with IC50 below 10 μg/mL. In PTK inhibition study, all bromophenol derivatives showed moderate inhibitory activity and compounds 2,
5 and 6 showed significant bioactivity with the inhibition ratio of 77.5%, 80.1% and 71.4%, respectively. Pharmacological
studies reveal that EELN could inhibit the growth of Sarcoma 180 tumor and increase the indices of thymus and spleen to improve
the immune system remarkably in vivo. Results indicated that the bromophenol derivatives and EELN can be used as potent antitumor agents for PTK over-expression
of c-kit and considered in a new therapeutic strategy for treatment of cancer.
Supported by the National High Technology Research and Development Program of China (863 Program, No. 2007AA09Z410) and Knowledge
Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-209) 相似文献
486.
In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate
venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the
total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process.
Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but
the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall
lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only
the high recovery efficiency for the venoms but high hemolytic activities as well.
Supported by the Award Foundation of Scientific Research for Excellent Young and Middle-age Scientist of Shandong Province
(No. 2006BS07003) and the Knowledge Innovation Project of Chinese Academy of Sciences (KZCX2-YW-R-104) 相似文献
487.
For the investigation of anti-infection immune response of Pseudosciaena crocea, 160 healthy fish samples were categorized into infected and control groups. Each individual fish in the infected group was
injected intraperitoneally (i.p.) with 0.2 ml bacterial suspension of Vibrio alginolyticus in density of 2×107 CFU/ml, while each individual in the control group was injected i.p. with 0.2 ml sterile saline solution (0.85%). It was
observed that the artificial injection of V. alginolyticus significantly increased the number of erythrocytes, leucocytes, lymphocytes in peripheral blood as well as peripheral serum
antibacterial activity and antibody titer of large yellow croaker, and significantly reduced the number of peripheral blood
granulocytes as compared with those in the control group. No significant difference in acid phosphytase and superoxide dismutase
activity of serum was detected between the two groups. It is suggested that non-specific immune factors including leucocytes
and anti-bacteria substance in peripheral blood played important role at the initial stage of infection, and specific immune
factors such as antibody then played important role in response to anti-infection at the latter stage.
Supported by the National High Technology Research and Development Program of China (863 program, No. 2007AA09Z115) and Technology
Program of Xiamen (No. 3502Z73019) 相似文献
488.
Flatfish or flounder moves one eye to change body proportion into vertebral asymmetry during metamorphosis, during which some
become sinistral while others dextral. However, the mechanism behinds the eye-position has not been well understood. In this
research, hybrids between Japanese flounder(♀) and stone flounder (♂) show mixed eye-location in both dextral type and sinistral
type, and thus become good samples for studying the eye-migration. mRNAs from pro-metamorphosis sinistral and dextral hybrids
larvae were screened with classical differential display RT-PCR (DD-RT-PCR) and representational difference analysis of cDNA
(cDNA-RDA); 30 and 47 putative fragments were isolated, respectively. The cDNA fragments of creatine kinase and trypsinogen
2 precursor genes isolated by cDNA-RDA exhibited eye-position expression patterns during metamorphosis. However, none of the
fragments was proved to be related to flatfishes’ eye-position specifically. Therefore, further studies and more sensitive
gene isolated methods are needed to solve the problems.
Supported by National Natural Science Foundation of China (No. 30600455) and the National Basic Research Program of China
(973 Program, No.2004CB117402) 相似文献
489.
Effects of iron electrovalence and species on growth and astaxanthin production of Haematococcus pluvialis 总被引:1,自引:1,他引:0
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies (Fe2+-EDTA and Fe3+-EDTA) and species (Fe-EDTA, Fe(OH)x32x and FeC6H5O7) addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies
have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe3+-EDTA, Fe2+-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content (30.70 mg/g biomass cell) was
obtained under conditions of 18 μmol/L Fe2+-EDTA, despite the lower cell density (2.3×105 cell/ml) in such condition. Fe3+-EDTA is more effective than Fe2+-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×105 cell/ml was obtained at 18 μmol/L Fe3+-EDTA addition. On the other hand, all the various species of iron (EDTA-Fe, Fe(OH)x32x, FeC6H5O7) are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration (36 μmol/L) of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The
present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe(OH)x32x and EDTA-Fe.
Supported by Xiamen Scientific and Technologic Projects (No. 3052Z20031086), Xiamen University Alumni Association Foundation
in Singapore, and the First National College Students Innovative Experimental Project 相似文献
490.
As the most widely used plasticizers in the world, phthalate esters (PAEs) are potential endocrine disruption compounds (EDCs).
In the present study, the toxicity of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl)
phthalate (DEHP) on embryogenesis and larvae development of the marine univalve Haliotis diversicolor supertexta was examined in laboratory. The results show that the malformation of embryos appeared during the experiment, such as embryos
died or lysed, small transparent flocculent rings studded on the periphery of the embryo, and the larvae could failed to hatch.
In embryo toxic test, embryos incubated at the highest concentration of DMP, DEP and DBP solutions showed significantly high
abnormal rate compared with the control, while DEHP solutions displayed no significant difference. In larval toxic test, in
all concentrations of DMP, DEP and DBP solutions, larval settlement rates were low significantly than that of the control.
Similarly, DEHP solutions show nearly no effect on the larval settlement. The order of toxicity on embryos and larvae is DBP>DEP>DMP>DEHP.
Being a simple and easy stimulation to indoor spawn, sensitive to environmental factors, and short culture time, the embryos
of H. diversicolor supertexta can be used to indicate toxicity of the PAEs.
Supported by National Natural Science Foundation of China (No. 40476057) 相似文献