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Biomedical subjects

Tao Hong

Publications and source records attributed to Tao Hong.

At least 19 recordsLinked to original sources
PubMed2007

Effects of validamycin on some enzymatic activities in soil.

There have been few investigations of the possible effects of validamycin on the enzymatic activities in soil. The objective of this present work was to study the short-term influence of enzymatic activity in validamycin treated soils. The results showed that high dose of validamycin introduced into soil had an significant effect on soil enzymatic activities, the degree of inhibition or promotion of enzymatic activities was not only related to the concentration of validamycin, but also to the remain time. Compared with the control (non treatment with validamycin), 240 ml.mg(-1) validamycin treatment caused a significant decrease (14%) of soil catalase activity; validamycin also inhibited urease activity to 67.3%, but subsequently, validamycin stimulated its activity higher than that of the control. Only the highest dose stimulated acid phophatase activities by 29.7%, and other concentration treatments had no effects on these enzymatic activities. The above results indicated that validamycin had effects on soil enzyme, but the effective time was short. It is also interesting to speculate that validamycin can be easily used by the soil microorganism as carbon source and energy.

Acid Phosphatase↗
PubMed2006

[In vivo transfer of human chemokine-like factor 1 gene increases peripheral blood CD34+ stem cells after myocardial infarction in rats].

OBJECTIVE: To assess the influence of different doses of CKLF1 plasmid on the dynamics and magnitude of the mobilization of the mobilization bone of marrow stem cells in a rat AMI model. METHODS: Different doses of plasmid DNA encoding CKLF1 gene, empty plasmid or saline were injected into male SD rats intramuscularly with in vivo electroporation. Rats were subjected to left coronary artery ligation 6 days after gene transfer. Peripheral blood samples were drawn and CD34+ cells were assayed by FACS calibur flow-cytometer. The changes in absolute number of CD34+ cells were evaluated. RESULTS: Expressions of CKLF1 mRNA and protein were detected in the injection site 7 days after gene transfer. Five days after gene transfer, the CD34+ cells numbers in CKLF1 groups were significantly higher than those in empty plasmid group, especially in CKLF1 100 microg group (16.63x10(6)/L vs 4.98x10(6)/L, P<0.01). On the 5-7 days, the CD34+ cell numbers in CKLF1 groups reached the peak and the peak number was 3.88 times that of baseline in CKLF1 100 microg group (P<0.01). After AMI, the cell numbers of 1 day to 7 days were significantly higher than those of the baseline in empty plasmid group and saline group. In comparison to empty plasmid group, CKLF1 groups were associated with still higher numbers of cells 1 day after AMI (P< 0.05), especially in CKLF1 100 microg group (14.61x10(6)/L vs 7.85x10(6)/L, P<0.01). CONCLUSION: CKLF1 gene transfer significantly increases the mobilization of CD34+ stem cells in acute myocardial infarction rats.

Animals↗
PubMed2006

ING2 PHD domain links histone H3 lysine 4 methylation to active gene repression.

Dynamic regulation of diverse nuclear processes is intimately linked to covalent modifications of chromatin. Much attention has focused on methylation at lysine 4 of histone H3 (H3K4), owing to its association with euchromatic genomic regions. H3K4 can be mono-, di- or tri-methylated. Trimethylated H3K4 (H3K4me3) is preferentially detected at active genes, and is proposed to promote gene expression through recognition by transcription-activating effector molecules. Here we identify a novel class of methylated H3K4 effector domains--the PHD domains of the ING (for inhibitor of growth) family of tumour suppressor proteins. The ING PHD domains are specific and highly robust binding modules for H3K4me3 and H3K4me2. ING2, a native subunit of a repressive mSin3a-HDAC1 histone deacetylase complex, binds with high affinity to the trimethylated species. In response to DNA damage, recognition of H3K4me3 by the ING2 PHD domain stabilizes the mSin3a-HDAC1 complex at the promoters of proliferation genes. This pathway constitutes a new mechanism by which H3K4me3 functions in active gene repression. Furthermore, ING2 modulates cellular responses to genotoxic insults, and these functions are critically dependent on ING2 interaction with H3K4me3. Together, our findings establish a pivotal role for trimethylation of H3K4 in gene repression and, potentially, tumour suppressor mechanisms.

Amino Acid Motifs↗
PubMed2006

Migration of F9 parietal endoderm cells is regulated by the ERK pathway.

Cell migration is regulated by the action of many signaling pathways that are activated in specific regions of migrating cells. Extracellular regulated kinase 1/2 (ERK) signaling can modulate the migration of cells by controlling the turnover of focal adhesions and the dynamics of actin polymerization. Focal adhesion turnover is necessary for cell migration, and the formation of strong actin stress fibers and mature focal adhesions puts the brakes on cell migration. We used F9 wild-type and vinculin null (vin-/-) parietal endoderm (PE) outgrowth to study the role of the ERK signaling pathway in cell migration. Upon plating of F9 embryoid bodies (EBs) onto laminin-coated dishes, PE cells migrate away from the EBs, providing an in vitro model for studying directed migration of this embryonic cell type. Our results suggest that the ERK pathway regulates PE cell migration by affecting the formation of focal adhesions and lamellipodia through the action of myosin light chain kinase (MLCK).

Animals↗
PubMed2006

Quasiparticle breakdown in a quantum spin liquid.

Much of modern condensed matter physics is understood in terms of elementary excitations, or quasiparticles--fundamental quanta of energy and momentum. Various strongly interacting atomic systems are successfully treated as a collection of quasiparticles with weak or no interactions. However, there are interesting limitations to this description: in some systems the very existence of quasiparticles cannot be taken for granted. Like unstable elementary particles, quasiparticles cannot survive beyond a threshold where certain decay channels become allowed by conservation laws; their spectrum terminates at this threshold. Such quasiparticle breakdown was first predicted for an exotic state of matter--super-fluid 4He at temperatures close to absolute zero, a quantum Bose liquid where zero-point atomic motion precludes crystallization. Here we show, using neutron scattering, that quasiparticle breakdown can also occur in a quantum magnet and, by implication, in other systems with Bose quasiparticles. We have measured spin excitations in a two-dimensional quantum magnet, piperazinium hexachlorodicuprate (PHCC), in which spin-1/2 copper ions form a non-magnetic quantum spin liquid, and find remarkable similarities with excitations in superfluid 4He. We observe a threshold momentum beyond which the quasiparticle peak merges with the two-quasiparticle continuum. It then acquires a finite energy width and becomes indistinguishable from a leading-edge singularity, so that excited states are no longer quasiparticles but occupy a wide band of energy. Our findings have important ramifications for understanding excitations with gapped spectra in many condensed matter systems, ranging from band insulators to high-transition-temperature superconductors.

Journal Article↗
PubMed2006

Neisseria bacilliformis sp. nov. isolated from human infections.

Most Neisseria species are gram-negative cocci or diplococci; currently, N. elongata is the only species of human origin with a bacillary morphology. Here, we report isolation and characterization of eight strains of another bacillary Neisseria species from human infections. The organisms caused or contributed to either oral cavity-related or respiratory tract infections, and two strains were isolated from blood cultures. The 16S rRNA gene sequences of these organisms, being homogenous or nearly so (99.4 to 100% identity), matched at <96% known Neisseria species and formed a distinct group within the genus. Analysis of the cellular fatty acids showed broad similarity with a few Neisseria species. The organisms were gram negative and measured 0.6 mum by 1.3 to 3.0 mum. They grew well on chocolate agar and on sheep blood agar but did not grow on modified Thayer-Martin agar. They were positive for oxidase and negative for indole production. There was no acid production from dextrose, lactose, maltose, or sucrose. The tests for catalase reaction, nitrate reduction, and tributilin varied with the strains. These results suggest that these organisms represent a novel species within the genus Neisseria, for which the name Neisseria bacilliformis sp. nov. is proposed. The type strain is MDA2833 = ATCC BAA-1200(T) = CCUG50858(T). Distinction between N. bacilliformis and N. elongata can be made confidently by 16S rRNA gene sequencing or cellular fatty acid profiling but may be difficult by morphology or routine biochemical tests.

Bacterial Typing Techniques↗
PubMed2006

[Dynamics of in vitro amyloid fiber formation of yeast prion protein Sup35NM].

BACKGROUND: To investigate the dynamics of amyloid fiber formation of yeast (Saccharomyces cerevisiae) prion protein Sup35NM under the native condition to provide materials and clues for the elucidation of amyloid fiber formation. METHODS: The Sup35NM gene was cloned and expressed in E. coli. The recombinant Sup35NM protein was purified under denaturing conditions through Nickel-Sepharose chromatography. Aliquots were removed at designated time points for transmission electron microscopy (TEM), circular dichroism (CD) spectra, protease K resistance assay, as well as thioflavin T (ThT) binding assay. RESULTS: The Sup35NM expressed and purified under denaturing conditions. The morphological alteration of the Sup35NM in PBS (pH7.4) during the protein aggregation and amyloid fiber formation was visualized by TEM. The CD assay showed that the course of amyloid fiber formation underwent a conformational shift from alpha-helix to beta-sheet. The fibers had higher capacity of resistance to protease K digestion compared to the monomers. ThT fluorescence assay displayed a rapid growth phase before reaching a final equilibrium phase during the fiber formation, and the higher concentration of Sup35NM could greatly accelerate the fiber formation in vitro. CONCLUSION: Yeast prion protein Sup35NM forms amyloid readily under native conditions in vitro. The dynamics of Sup35NM amyloid formation may provide supporting evidences for the nucleating polymerization models of amyloid fiber formation.

Amyloid beta-Peptides↗
PubMed2006

[Eco-value level classification model of forest ecosystem based on modified projection pursuit technique].

To optimize the projection function and direction of projection pursuit technique, predigest its realization process, and overcome the shortcomings in long time calculation and in the difficulty of optimizing projection direction and computer programming, this paper presented a modified simplex method (MSM), and based on it, brought forward the eco-value level classification model (EVLCM) of forest ecosystem, which could integrate the multidimensional classification index into one-dimensional projection value, with high projection value denoting high ecosystem services value. Examples of forest ecosystem could be reasonably classified by the new model according to their projection value, suggesting that EVLCM driven directly by samples data of forest ecosystem was simple and feasible, applicable, and maneuverable. The calculating time and value of projection function were 34% and 143% of those with the traditional projection pursuit technique, respectively. This model could be applied extensively to classify and estimate all kinds of non-linear and multidimensional data in ecology, biology, and regional sustainable development.

Ecosystem↗
PubMed2006

[Changes of species diversity in gap gradient of mid-subtropical evergreen broad-leaved forest in Wanmulin Forest].

Based on the investigation of gap and non-gap stands in the mid-subtropical evergreen broad-leaved forest in Wanmulin Nature Reserve of Fujian Province, this paper studied the changes of species diversity in gap gradient and in gaps with different sizes. The results showed that the species richness and diversity decreased gradually from gap center to non-gap, ecological dominance was higher in center and lower in edges, and species evenness was in adverse to ecological dominance. The species diversity in all areas of gap was the maximum when the gap size was 200 to approximately 300 m2.

Biodiversity↗
PubMed2006

[Evaluation of the relationship between IL-18 levels in urine and parameters of renal pathological changes in patients with lupus nephritis].

AIM: To evaluate the relationship between IL-18 levels in urine and parameters of renal pathological changes in patients with lupus nephritis (LN). METHODS: IL-18 levels in morning free urine and 24-hour's urine in 19 normal persons and 55 patients with LN were measured by ELISA. The correlation between IL-18 levels and parameters of renal pathological changes, namely activity index (AI) and chronicity index (CI), were analyzed by liner correlation analysis method. RESULTS: IL-18 levels in morning free urine and 24-hour's urine in LN group were elevated significantly compared with control group. In both groups IL-18 levels in morning free urine were (247.1+/-317.5) ng/L and (20.3+/-14.5) ng/L, respectively, P<0.001; those in 24-hour's urine were (192.1+/-170.1) ng/d and (21.0+/-3.8) ng/d, respectively, (P<0.001). There was close positive correlation between IL-18 levels in morning free urine and 24-hour's urine and LN patient's AI (for morning free urine: r=0.602, P<0.001; for 24-hour's urine: r=0.461, P<0.005) but there was no correlation between IL-18 levels in morning urine and 24-hour's urine and CI (P>0.05). Patients with LN were divided into three groups (high, moderate and low) according to AI value. There was distinct difference of IL-18 levels in urine among the three groups: IL-18 levels in morning urine were (69.2+/-82.7) ng/L, (193.5+/-106.1) ng/L and (580.7+/-453.1) ng/L, respectively, (P<0.001); those in 24-hour's urine were (103.5+/-141.4) ng/d, (188.8+/-124.0) ng/d and (333.1+/-183.2) ng/d, respectively. CONCLUSION: It is very simple and convenient to detect IL-18 levels in morning free urine, so it is a good method for evaluating renal pathological activity of LN.

Chronic Disease↗
PubMed2006

[Relationship between leptin gene of adipose tissues and nonalcoholic fatty liver disease].

OBJECTIVE: To investigate leptin mRNA expressions in subcutaneous (SC) and omental (OM) adipose tissues of patients with nonalcoholic fatty liver disease (NAFLD), and their relationships with insulin resistance (IR), blood leptin, blood triglyceride, total blood cholesterol, blood glucose, body weight index and waist-hip ratio. METHODS: SC and OM adipose tissues were obtained from 10 obese and 11 nonobese NAFLD patients and from 11 obese and 13 nonobese patients without NAFLD, who served as controls. Leptin mRNA expression levels in the subcutaneous and omental adipose tissues were measured using SYBR Green I quantitative real-time PCR. IR was estimated using homeostasis assessment (HOMA). The levels of plasma leptin and insulin were measured using ELISA. RESULTS: The relative mRNA expression of leptin, HOMA-IR and blood leptin levels in NAFLD differed significantly from those of the controls (P < 0.05). The leptin/GAPDH ratio of the obese and nonobese NAFLD and control cases were 1.32 +/- 0.12, 0.99 +/- 0.05, 1.10 +/- 0.09, 0.87 +/- 0.13 respectively. The expression levels of SC and OM adipose leptin mRNA in NAFLD patients were positively correlated with HOMA-IR (r=0.72, P < 0.05), blood leptin (r=0.69, P < 0.05), blood triglyceride (r=0.32, P < 0.05), body weight index (r=0.57, P < 0.05) and waist-hip ratio (r=0.50, P <0.05). CONCLUSION: The primary reason for high levels of blood leptin is high leptin mRNA expression in adipose tissues; in both obese and nonobese patients with NAFLD; high levels of blood leptin and the leptin mRNA expression in adipose tissues and IR exist. These findings suggest that leptin resistance exists in patients with NAFLD and leptin resistance is positively correlated with NAFLD, the same as in insulin resistance.

Adipose Tissue↗
PubMed2005

Escherichia coli: development of carbapenem resistance during therapy.

A 76-year-old woman had recurrent urosepsis due to extended-spectrum beta -lactamase-positive Escherichia coli. Imipenem resistance was detected after long-term imipenem-meropenem therapy. The carbapenem-hydrolyzing enzyme gene was identified as blaKPC-3. To our knowledge, this is the first documented case in which carbapenem-resistant E. coli emerged during therapy with imipenem and meropenem, and the first identification of the carbapenem-hydrolyzing enzyme in E. coli isolates.

Aged↗
PubMed2005

Optical clocks based on ultranarrow three-photon resonances in alkaline Earth atoms.

A sharp resonance line that appears in three-photon transitions between the 1S0 and 3P0 states of alkaline earth and Yb atoms is proposed as an optical frequency standard. This proposal permits the use of the even isotopes, in which the clock transition is narrower than in proposed clocks using the odd isotopes and the energy interval is not affected by external magnetic fields or the polarization of trapping light. With this method, the width and the rate of the clock transition can, in principle, be continuously adjusted from the MHz level to sub-mHz without loss of signal amplitude by varying the intensities of the three optical beams. Doppler and recoil effects can be eliminated by proper alignment of the three optical beams or by point confinement in a lattice trap. Light-shift effects on the clock accuracy can be limited to below a part in 10(18).

Journal Article↗
PubMed2005

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus.

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS.

Animals↗