Biomedical subjects

Fashui Hong

Publications and source records attributed to Fashui Hong.

9 recordsLinked to original sources

PubMed2006

Interaction mechanism between Cd2+ ions and DNA from the kidney of the silver crucian carp.

Cadmium is one of the most toxic heavy metals and is known to accumulate in freshwater food chains. The underlying mechanism for its genotoxicity has not been investigated for any freshwater fish. It has, however, been suggested that cadmium-induced carcinogenesis might involve either direct or indirect interaction of Cd2+ with DNA. The interaction between Cd2+ and DNA from the kidney of the silver crucian carp (Carassius auratus gibelio) in vitro and in vivo is investigated by spectrophotometric methods and agarose gel electrophoresis methods. Cd2+ could insert into DNA basepairs, bind to nucleic acid, and result in notable hypochromicities. The analysis of agarose gel electrophoresis proves that Cd2+ at different concentrations does not cause DNA cleavage in vitro; however, kidneys display the classical laddering degradation of DNA in vivo, which is the result of the promotion of deoxyribonuclease activity or inhibition of superoxide dismutase and catalyse activity and the accumulation of reactive oxygen species caused by Cd2+ ions in vivo.

Animals↗

PubMed2006

Influences of nano-anatase TiO2 on the nitrogen metabolism of growing spinach.

Previous research showed that nano-TiO2 could significantly promote photosynthesis and greatly improve growth of spinach, but we also speculated that an increase of spinach growth by nano-TiO2 treatment might be closely related to the change of nitrogen metabolism. The effects of nanoanatase TiO2 on the nitrogen metabolism of growing spinach were studied by treating them with nano-anatase TiO2. The results showed that nano-anatase TiO2 treatment could obviously increase the activities of nitrate reductase, glutamate dehydrogenase, glutamine synthase, and glutamic-pyruvic transaminase during the growing stage. Nano-anatase TiO2 treatment could also promote spinach to absorb nitrate, accelerate inorganic nitrogen (such as NO3--N and NH4+-N) to be translated into organic nitrogen (such as protein and chlorophyll), and enhance the fresh weight and dry weights.

Chlorophyll↗

PubMed2006

Mechanism of nano-anatase TiO2 on promoting photosynthetic carbon reaction of spinach: inducing complex of rubisco-rubisco activase.

Having a photocatalyzed characteristic, our previous research had proved that nano-anatase TiO2 is closely related to the photosynthesis of spinach. It could not only improve the light absorbance and the transformation from light energy to electron energy and to active chemical energy but also promote carbon dioxide (CO2) assimilation of spinach. However, the mechanism of carbon reaction promoted by nano-anatase TiO2 remains largely unclear. By electrophoresis and Western blot methods, the results of the experiments proved that Rubisco from the nano-anatase TiO2-treated spinach during the extraction procedure of Rubisco was found to consist of Rubisco and a heavier molecular-mass protein (about 1,200 kDa) comprising both Rubisco and Rubisco activase. The Rubisco carboxylase activity was 2.67 times that of Rubisco from the control and it could hydrolyze ATP in the same manner as Rubisco activase. The total sulfhydryl groups and available sulfhydryl groups of the Rubisco were 32 -SH and 21 -SH per mole of enzyme more than those of the Rubisco purified from the control, respectively. The circular dichroism spectra showed that the secondary structure of Rubisco from the nano-anatase TiO2-treated spinach was very different from Rubisco of the control. It suggested that the mechanism of nano-anatase TiO2 activating Rubisco of spinach was that the complex of Rubsico and Rubisco activase was induced in spinach, which promoted Rubsico carboxylation and increased the rate of photosynthetic carbon reaction.

Carbon Dioxide↗

PubMed2006

Regulative mechanism of Ce3+ relieves DNA damage caused by Cd2+ in the kidney of silver crucian carp.

The mechanism of Cd2+ on the DNA cleavage and Ce3+ on the DNA repair in the kidney of silver crucian carp (Carassius auratus gibelio) is investigated by agarose gel electrophoresis methods and assaying biochemical indexes. It proves that Cd2+ induces the classical laddering degradation of DNA in vivo, but DNA cleavage is repaired after injecting with a low Ce3+ concentration under various Cd2+ concentrations. The DNA cleavage caused by Cd2+ is the result of the activation of deoxyribonuclease (DNase) and accumulation of reactive oxygen species (ROS), and Cd2+ destroys the antioxidant system, which diminishes the activities of superoxide dismutase, catalase, and peroxidase, and the increase of the lipid peroxidation (LPO) level. However, Ce3+ could inhibit activation of Cd2+ on DNase activity, relieve inhibition of Cd2+ on activities of the antioxidant enzyme, and diminish ROS accumulation. The results show that Ce3+ could relieve the toxicity of Cd2+ to silver crucian carp.

Animals↗

PubMed2005

Effect of nano-TiO(2) on strength of naturally aged seeds and growth of spinach.

The effects of nano-TiO(2) (rutile) and non-nano-TiO(2) on the germination and growth of naturally aged spinach seeds were studied by measuring the germination rate and the germination and vigor indexes of aged spinach seeds. An increase of these factors was observed at 0.25-4% nano-TiO(2) treatment. During the growth stage, the plant dry weight was increased, as was the chlorophyll formation, the ribulosebisphosphate carboxylase/oxygenase activity, and the photosynthetic rate. The best results were found at 2.5% nano-TiO(2). The effects of non-nano-TiO(2) are not significant. It is shown that the physiological effects are related to the nanometer-size particles, but the mechanism by which nano-TiO(2) improves the growth of spinach seeds still needs further study.

Chlorophyll↗

PubMed2005

Influences of nano-TiO2 on the chloroplast aging of spinach under light.

The effects of nano-TiO2 (rutile) on the chloroplast aging of spinach under light were studied. The results showed that when the chloroplasts were illuminated for 1, 5, and 10 min with 500 micromol/cm2/min light intensity, respectively, the evolution oxygen rate was rapidly increased; when the chloroplasts were treated for 20, 30, and 40 min with 500 micromol/cm2/min light intensity, respectively, the evolution oxygen rate was gradually decreased. While spinach was treated with 0.25% nano-TiO2, the rate of evolution oxygen of chloroplasts in different illumination times (1, 5, 10, 20, 30, and 40 min) was higher than that of control, and when the illumination time was over 10 min, the reduction of the evolution oxygen rate was lower than that of control. It suggested that nano-TiO2 treatment could protect chloroplasts from aging for long-time illumination. The mechanism researches indicated that nano-TiO2 treatment could significantly increase the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), decrease accumulation of reactive oxygen free radicals and the level of malondialdehyde (MDA), and maintain stability of membrane structure of chloroplast under light.

Catalase↗

PubMed2005

Effect of nano-TiO2 on photochemical reaction of chloroplasts of spinach.

The effects of nano-TiO2 (rutile) on the photochemical reaction of chloroplasts of spinach were studied. The results showed that when spinach was treated with 0.25% nano-TiO2, the Hill reaction, such as the reduction rate of FeCy, and the rate of evolution oxygen of chloroplasts was accelerated and noncyclic photophosphorylation (nc-PSP) activity of chloroplasts was higher than cyclic photophosphorylation (c-PSP) activity, the chloroplast coupling was improved and activities of Mg2+-ATPase and chloroplast coupling factor I (CF1)-ATPase on the thylakoid membranes were obviously activated. It suggested that photosynthesis promoted by nano-TiO2 might be related to activation of photochemical reaction of chloroplasts of spinach.

Biochemistry↗

PubMed2005

Prevention by Ce3+ of DNA destruction caused by Hg2+ in fish intestine.

The interactions between Hg2+, Ce3+, and the mixture of Ce3+ and Hg2+, and DNA from fish intestine in vitro were investigated by using absorption spectrum and fluorescence emission spectrum. The ultraviolet absorption spectra indicated that the addition of Hg2+, Ce3+, and the mixture of Ce3+ and Hg2+ to DNA generated an obviously hypochromic effect. Meanwhile, the peak of DNA at 205.2 nm blue-shifted and at 258.2 nm red-shifted. The size of the hypochromic effect and the peak shift of DNA by metal ion treatments was Hg2+>Hg2++Ce3+>Ce3+. The fluorescence emission spectra showed that with the addition of Hg2+, Ce3+, and the mixture of Ce3+ and Hg2+ the emission peak at about 416.2 nm of DNA did not obviously change, but the intensity reduced gradually and the sequence was Hg2+>Hg2++ Ce3+>Ce3+. Hg2+, Ce3+, and the mixture of Ce3+ and Hg2+ had 1.12, 0.19, and 0.41 binding sites to DNA, respectively; the fluorescence quenching of DNA caused by the metal ions all attributed to static quenching. The binding constants (KA) of binding sites were 8.98 x 104 L/mol and 1.02 x 104 L/mol, 5.12 x 104 L/mol and 1.10 x 103 L/mol, 6.66 x 104 L/mol and 2.36 x 103 L/mol, respectively. The results showed that Ce3+ could relieve the destruction of Hg2+ on the DNA structure.

Animals↗

PubMed2005

Structural differences between light and heavy rare earth element binding chlorophylls in naturally grown fern: Dicranopteris linearis.

Chloroplasts and chlorophylls were isolated from the leaves of Dicranopteris linearis, a natural perennial fern sampled at rare earth element (REE) mining areas in the South-Jiangxi region (southern China). The inductively coupled plasma-mass spectrometry (ICP-MS) results indicated that REEs were present in the chloroplasts and chlorophylls of D. linearis. The in vivo coordination environment of light REE (lanthanum) or heavy REE (yttrium) ions in D. linearis chlorophyll-a was determined by the extended X-ray absorption fine structure (EXAFS). Results revealed that there were eight nitrogen atoms in the first coordination shell of the lanthanum atom, whereas there were four nitrogen atoms in the first coordination shell of yttrium. It was postulated that the lanthanum-chlorophyll-a complex might have a double-layer sandwich-like structure, but yttrium-binding chlorophyll-a might be in a single-layer form. Because the content of REE-binding chlorophylls in D. linearis chlorophylls was very low, it is impossible to obtain structural characteristics of REE-binding chlorophylls by direct analysis of the Fourier transform infrared (FTIR) and ultraviolet (UV)-visible spectra of D. linearis chlorophylls. In order to acquire more structural information of REE-binding chlorophyll-a in D. linearis, lanthanum - and yttrium-chlorophyll-a complexes were in vitro synthesized in acetone solution. Element analyses and EXAFS results indicated that REE ions (lanthanum or yttrium) of REE-chlorophyll-a possessed the same coordination environment whether in vivo or in vitro. The FTIR spectra of the REE-chlorophyll-a complexes indicated that REEs were bound to the porphyrin rings of chlorophylls. UV-visible results showed that the intensity ratios of Soret to the Q-band of REE-chlorophyll-a complexes were higher than those of standard chlorophyll-a and pheophytin-a, indicating that REE-chlorophyll-a might have a much stronger ability to absorb the ultraviolet light. The MCD spectrum in the Soret band region of lanthanum-chlorophyll-a showed a special peak, but yttrium-chlorophyll-a did not have this special peak, corresponding well to their double-layer and single-layer structure, respectively.

Chlorophyll↗