Search PubMed⌕ Search

Biomedical subjects

Ping Wu

Publications and source records attributed to Ping Wu.

At least 127 records · Page 7Linked to original sources
PubMed2003

Identification and characterization of a new human type 9 cGMP-specific phosphodiesterase splice variant (PDE9A5). Differential tissue distribution and subcellular localization of PDE9A variants.

Previously, four splice variants of human cGMP-specific phosphodiesterase (PDE) 9A (PDEs 9A1, 9A2, 9A3 and 9A4) have been identified. In this study, we have cloned a cDNA representing a new human PDE9A variant (PDE9A5). PDE9A5 encodes a protein of 492 amino acids, smaller than PDEs 9A1 and 9A2 but larger than PDEs 9A3 and 9A4. The exon structure of PDE9A5 is different from those of PDEs 9A1, 9A2, 9A3 and 9A4 in that, of the 20 exons of PDE9A gene, it lacks exons 2 and 5. PDE9A5 has been characterized in comparison with PDE9A1, the longest PDE9A variant. PDEs 9A5 and 9A1 have similar enzymatic properties. They both have a high affinity for cGMP with similar Km values (0.39 and 0.25 microM, respectively), although they have slightly different Vmax values (2.55 and 0.96 micromol/min/mg, respectively). They exhibit very similar divalent metal ion dependency and inhibitor sensitivity. Real-time quantitative PCR analysis shows that PDEs 9A5 and 9A1 exhibit differential tissue distribution. They are highly expressed in immune tissues (spleen, lymph node and thymus) and are more abundant in T cells than in B cells, neutrophils and monocytes. When transiently expressed in HEK293 cells, PDEs 9A5 and 9A1 proteins exhibit differential subcellular localization. PDE9A5 localizes exclusively in the cytoplasm, whereas PDE9A1 localizes in the nucleus only. The nuclear localization of PDE9A1 is dependent on a unique pat7 motif. By Western blot analysis, native PDE9A1 is detectable in the nucleus but not in the cytoplasm of T cells. Thus, to our knowledge, PDE9A1 is the only PDE isoform found to localize exclusively in the nucleus. We speculate that the physiological role of the PDE9A diversity may be imparting cGMP-metabolizing ability to specific cellular compartments in appropriate tissues.

1-Methyl-3-isobutylxanthine↗
PubMed2003

Sorption behavior of 2,4-dichlorophenol on marine sediment.

The sorption behavior of 2,4-dichlorophenol on marine sediments treated by different methods was investigated systematically. The sorption of 2,4-dichlorophenol on marine sediments was completed mainly via ion exchange and surface polar sorption. Both the Freundlich and Langmuir isotherms were fit for describing its sorption behavior. The sorption behavior of 2,4-dichlorophenol was affected by various factors including aqueous salinity and temperature. The sorption amount of 2,4-dichlorophenol on marine sediments increased with increasing ion strength, but decreased with increasing temperature.

Adsorption↗
PubMed2003

Cloning and characterization of the granule-bound starch synthase II gene in rice: gene expression is regulated by the nitrogen level, sugar and circadian rhythm.

A full-length coding domain sequence of a gene analogous to granule-bound starch synthase (GBSS; ADP-glucose-starch glucosyltransferase, EC 2.4.1.21) was cloned and defined as OsGBSSII based on a Nitrogen (N)-starvation-induced cDNA library constructed using the rapid subtraction hybridization method. The deduced amino acid sequence of OsGBSSII was 62-85% identical to those of GBSS proteins from other plant species. The exon/intron organization of OsGBSSII was similar to that of OsGBSSI. OsGBSSII was mainly expressed in leaves and its protein was exclusively bound to starch granules in rice leaves, which suggests that the amylose in rice leaves is synthesized by OsGBSSII. N-starvation-induced expression of OsGBSSII could be repressed by supplying nitrate, ammonia or amino acid (glutamic acid or glutamine), glucosamine (an inhibitor of hexokinase) or dark conditions. These results indicate that N-starvation induction was dependent on the photosynthetic product and hexokinase in rice leaves. Sugars induced the accumulation of OsGBSSII transcripts in excised leaves through glycolysis-dependent pathways. OsGBSSII gene expression is regulated by the circadian rhythm in rice leaves.

Amino Acid Sequence↗
PubMed2003

Adaptation to the sky: Defining the feather with integument fossils from mesozoic China and experimental evidence from molecular laboratories.

In this special issue on the Evo-Devo of amniote integuments, Alibardi has discussed the adaptation of the integument to the land. Here we will discuss the adaptation to the sky. We first review a series of fossil discoveries representing intermediate forms of feathers or feather-like appendages from dinosaurs and Mesozoic birds from the Jehol Biota of China. We then discuss the molecular and developmental biological experiments using chicken integuments as the model. Feather forms can be modulated using retrovirus mediated gene mis-expression that mimics those found in nature today and in the evolutionary past. The molecular conversions among different types of integument appendages (feather, scale, tooth) are discussed. From this evidence, we recognize that not all organisms with feathers are birds, and that not all skin appendages with hierarchical branches are feathers. We develop a set of criteria for true avian feathers: 1) possessing actively proliferating cells in the proximal follicle for proximo-distal growth mode; 2) forming hierarchical branches of rachis, barbs, and barbules, with barbs formed by differential cell death and bilaterally or radially symmetric; 3) having a follicle structure, with mesenchyme core during development; 4) when mature, consisting of epithelia without mesenchyme core and with two sides of the vane facing the previous basal and supra-basal layers, respectively; and 5) having stem cells and dermal papilla in the follicle and hence the ability to molt and regenerate. A model of feather evolution from feather bud --> barbs --> barbules --> rachis is presented, which is opposite to the old view of scale plate --> rachis --> barbs --> barbules (Regal, '75; Q Rev Biol 50:35).

Adaptation, Biological↗
PubMed2003

Molecular biology of feather morphogenesis: a testable model for evo-devo research.

Darwin's theory describes the principles that are responsible for evolutionary change of organisms and their attributes. The actual mechanisms, however, need to be studied for each species and each organ separately. Here we have investigated the mechanisms underlying these principles in the avian feather. Feathers comprise one of the most complex and diverse epidermal organs as demonstrated by their shape, size, patterned arrangement and pigmentation. Variations can occur at several steps along each level of organization, leading to highly diverse forms and functions. Feathers develop gradually during ontogeny through a series of steps that may correspond to the evolutionary steps that were taken during the phylogeny from a reptilian ancestor to birds. These developmental steps include 1) the formation of feather tract fields on the skin surfaces; 2) periodic patterning of the individual feather primordia within the feather tract fields; 3) feather bud morphogenesis establishing anterio-posterior (along the cranio-caudal axis) and proximo-distal axes; 4) branching morphogenesis to create the rachis, barbs and barbules within a feather bud; and 5) gradual modulations of these basic morphological parameters within a single feather or across a feather tract. Thus, possibilities for variation in form and function of feathers occur at every developmental step. In this paper, principles guiding feather tract formation, distributions of individual feathers within the tracts and variations in feather forms are discussed at a cellular and molecular level.

Animals↗
PubMed2003

Safety assessment for genetically modified sweet pepper and tomato.

The coat protein (CP) gene of cucumber mosaic virus (CMV) was cloned from a Chinese CMV isolate, the CaMV promoter and NOS terminator added and the gene construct was transformed into both sweet pepper and tomato plants to confer resistance to CMV. Safety assessments of these genetically modified (GM) plants were conducted. It was found that these two GM products showed no genotoxicity either in vitro or in vivo by the micronucleus test, sperm aberration test and Ames test. Animal feeding studies showed no significant differences in growth, body weight gain, food consumption, hematology, blood biochemical indices, organ weights and histopathology between rats or mice of either sex fed with either GM sweet pepper or tomato diets compared with those with non-GM diets. These results demonstrate that the CMV-resistant sweet pepper and tomato are comparable to the non-GM counterparts in terms of food safety.

Animals↗
PubMed2003

Efficiencies of transgene expression in nociceptive neurons through different routes of delivery of adeno-associated viral vectors.

Transferring therapeutic genes into the nociceptive system, including dorsal root ganglia (DRGs) and the spinal cord, is potentially a powerful approach for the treatment of chronic pain in humans. Adeno-associated viral vectors (AAVs) are particularly useful in delivering foreign genes to targeted tissues because they seldom induce immune responses or produce cytotoxicity. To determine the efficiency of transgene expression and the best route(s) of delivery, a recombinant AAV type 2 vector containing the enhanced green fluorescent protein (EGFP) gene driven by the neuron-specific enolase (NSE) promoter (rAAV-EGFP) was constructed. We injected the vector into subcutaneous tissue, sciatic nerve, DRGs, and subarachnoid space, and examined EGFP expression in the DRG, spinal cord, and nerve fibers. Both sciatic nerve and DRG injection led to strong EGFP expression in a large number of DRG neurons. The expression persisted for more than 6-8 months. We then delivered the mu-opioid receptor (muOR) gene into DRGs through direct DRG or sciatic nerve injection of rAAV-muOR and found a significant increase in morphine efficacy. These results suggest that delivering therapeutic genes to DRGs by the rAAV-NSE vector is a valid strategy for treatment of chronic pain.

Analgesics, Opioid↗
PubMed2003

Targeting the MraY and MurG bacterial enzymes for antimicrobial therapeutic intervention.

Assays for two enzymes from Escherichia coli were developed and validated as antibacterial inhibitor screens. The MraY and MurG enzymes were overexpressed and purified as the membrane fraction or to homogeneity, respectively. The MurG enzyme was expressed with a six-histidine tag using an optimized minimal-medium protocol for subsequent purification. Although traditional assays were established, the enzymes were also assayed via a 96-well membrane plate assay and a 384-well scintillation proximity-based assay developed herein. These assays afford a more economical and high-throughput evaluation of inhibitors. A mureidomycin inhibitor mix was used as a control for the assay development and screen validation. Several inhibitors resulting from a high-throughput screen were found and evaluated for potential therapeutic use.

Anti-Bacterial Agents↗
PubMed2003

Chemical reactivity of Ro-26-9228, 1alpha-fluoro-25-hydroxy-16,23E-diene-26,27-bishomo-20-epi-cholecalciferol in aqueous solution.

The degradation of Ro-26-9228, 1alpha-fluoro-25-hydroxy-16,23E-diene-26,27-bishomo-20-epi-cholecalciferol, 2, was studied in aqueous solution in the pH range of 1.17-10.56 and in alcohol solutions, at 25, 40, and 50 degrees C. The degradation of Ro-26-9228 was found to be acid catalyzed and to be independent of potassium acetate buffer concentration. Above pH 4, the reaction rate is independent of pH, with a T90 of 14.3 h at 25 degrees C in pH 7.75 buffer. 19F nuclear magnetic resonance was used to study the ratio of the vitamin (6-s-trans) to previtamin form in acetonitrile at 40 degrees C. The equilibrium percentage of previtamin and the rate of approach to equilibrium were 13.8% and 0.2 h(-1), respectively. Nuclear magnetic resonance was used to elucidate the structure of the degradation products. Novel products were formed from the elimination of the fluorine and addition of solvent to C9, with formation occurring through the previtamin form. Additional degradation products result from reaction of the side chain 25-hydroxyl and addition of solvent to C1.

2-Propanol↗
PubMed2003

Isolation and characterization of two fructokinase cDNA clones from rice.

Two cDNA clones, OsFKI and OsFKII, encoding fructokinase (EC 2.7.1.4) were isolated from immature seeds of rice (Oryza sativa L.) by PCR. OsFKI cDNA encoded a deduced protein of 323 amino acids that was 59-71% identical to previously characterized plant fructokinases. In contrast, OsFKII cDNA encoded a deduced protein of 336 amino acids that shared only 64% amino acid identity with OsFKI. The deduced proteins both possessed an ATP-binding motif and putative substrate recognition site sequences that were previously identified in bacterial fructokinases. Genomic DNA blot analysis also revealed that each fructokinase gene exists as a single copy in the rice genome. The identity of OsFKI and OsFKII as fructokinases was confirmed by the expression of enzyme activity in E. coli. Although both OsFKI and OsFKII utilized fructose as substrate, only OsFKII activity was strongly inhibited at a high fructose concentration. The mRNA corresponding to OsFKII accumulated at high levels in developing rice grains, whereas there were only low levels of OsFKI transcripts in immature seeds. These results indicate that fructokinase in rice endosperm is encoded by two divergent genes, which play different roles in rice grains for starch storage based on their sensitivity to substrate inhibition and level of transcripts in endosperm.

Amino Acid Sequence↗
PubMed2003

Effect of high temperature on fine structure of amylopectin in rice endosperm by reducing the activity of the starch branching enzyme.

Rice (Oryza sativa L.) grain quality is affected by the environmental temperature it experiences. To investigate the physiological molecular mechanisms of the effect of high temperatures on rice grain, a non-waxy indica rice was grown under two temperature conditions, (29/35 degrees C) and (22/28 degrees C), during the ripening stage in two phytotrons. The activities and gene expression of key enzymes for the biosynthesis of amylose and amylopectin were examined. The activity and expression levels of soluble endosperm starch synthase I were higher at 29/35 degrees C than that at 22/28 degrees C. In contrast, the activities and expression levels of the rice branching enzyme1, the branching enzyme3 and the granule bound starch synthase of the endosperm were lower at 29/35 degrees C than those at 22/28 degrees C. These results suggest that the decreased activity of starch branching enzyme reduces the branching frequency of the branches of amylopectin, which results in the increased amount of long chains of amylopectin of endosperm in rice grain at high temperature.

1,4-alpha-Glucan Branching Enzyme↗
PubMed2003

Weighted two-band target entropy minimization for the reconstruction of pure component mass spectra: simulation studies and the application to real systems.

A method is proposed, on the basis of a recently developed algorithm--Band Target Entropy Minimization (BTEM)--to reconstruct mass spectra of pure components from mixture spectra. This method is particular useful in dealing with spectral data with discrete features (like mass spectra). Compared to the original BTEM, which has been applied to differentiable spectroscopies such as Fourier-transfer infrared spectroscopy (FTIR), ultraviolet (UV), Raman, and nuclear magnetic resonance (NMR), the latest modifications were obtained through: (1) Reformulating the objective function using the peak heights instead of their derivatives; (2) weighting the abstract vector VT to reduce the effect of noise; (3) using a two-peak targeting strategy (tBTEM) to deal with strongly overlapping peaks; and (4) using exhaustive search to locate all the component spectra. A set of 50 multi-component mass spectra was generated from ten reference experimental pure component spectra. Many of the compounds chosen have common MS fragments and therefore, many of the pure component spectra have considerable intensity in same data channels. In addition, a set of MS spectra from a real system with four components was used to examine the newly developed algorithm. Successful reconstruction of the ten component spectra of the simulated system and the four component spectra of the real system was rapidly achieved using the new tBTEM algorithm. The advantages of the new algorithm and its implication for rapid system identification of unknown mixtures are readily apparent.

Journal Article↗
PubMed2003

Distribution and characterization of over 1000 T-DNA tags in rice genome.

We generated T-DNA insertions throughout the rice genome for saturation mutagenesis. More than 1,000 flanking sequences were mapped on 12 rice chromosomes. Our results showed that T-DNA tags were not randomly spread on rice chromosomes and were preferentially inserted in gene-rich regions. Few insertions (2.4%) were found in repetitive regions. T-DNA insertions in genic (58.1%) and intergenic regions (41.9%) showed a good correlation with the predicted size distribution of these sequences in the rice genome. Whereas, obvious biases were found for the insertions in the 5'- and 3'-regulatory regions outside the coding regions both at 500-bp size and in introns rather than in exons. Such distribution patterns and biases for T-DNA integration in rice are similar to that of the previous report in Arabidopsis, which may result from T-DNA integration mechanism itself. Rice will require approximately the same number of T-DNA insertions for saturation mutagenesis as will Arabidopsis. A database of the T-DNA insertion sites in rice is publicly available at our web site (http://www.genomics.zju.edu.cn/ricetdna).

DNA, Bacterial↗
PubMed2003

Effects of all-trans retinoic acid (ATRA) on human myeloma cells.

All-trans retinoic acid (ATRA) is a natural oxidative metabolite of Vitamin A (retinol) and is known to be a regulator of cell proliferation differentiation, especially in various malignant cells. The cyto-differentiating action of ATRA has led to its usage in the treatment of several malignancies, particularly acute promyelocytic leukemia (APL). There have been many reports regarding the cell biological effects of ATRA on human myeloma cells and a few clinical trials. Most of these reports have revealed growth inhibition by ATRA mediated by down-regulation of the IL-6/IL-6R auto/paracrine loop, and upregulation of p21/Cip1. Here, we review previous reports and introduce experimental results obtained using various myeloma cell lines established in our laboratory.

Antineoplastic Agents↗
PubMed2003

Phosphate starvation triggers distinct alterations of genome expression in Arabidopsis roots and leaves.

Arabidopsis genome expression pattern changes in response to phosphate (Pi) starvation were examined during a 3-d period after removal of Pi from the growth medium. Available Pi concentration was decreased after the first 24 h of Pi starvation in roots by about 22%, followed by a slow recovery during the 2nd and 3rd d after Pi starvation, but no significant change was observed in leaves within the 3 d of Pi starvation. Microarray analysis revealed that more than 1,800 of the 6,172 genes present in the array were regulated by 2-fold or more within 72 h from the onset of Pi starvation. Analysis of these Pi starvation-responsive genes shows that they belong to wide range of functional categories. Many genes for photosynthesis and nitrogen assimilation were down-regulated. A complex set of metabolic adaptations appears to occur during Pi starvation. More than 100 genes each for transcription factors and cell-signaling proteins were regulated in response to Pi starvation, implying major regulatory changes in cellular growth and development. A significant fraction of those regulatory genes exhibited distinct or even contrasting expression in leaves and roots in response to Pi starvation, supporting the idea that distinct Pi starvation response strategies are used for different plant organs in response to a shortage of Pi in the growth medium.

Arabidopsis↗
PubMed2003

[Expression of cyclooxygenase-2 mRNA and identification of its spliceriant in human myometrium obtained from women in labor].

OBJECTIVE: To investigate the expression of cyclooxygenase-2 (COX-2) in human lower segments of myometrium obtained from women in labor and those not in labor and identify the splice variant of COX-2. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for investigating the expression of COX-2. According to the sequence of rat COX-2 splice variant, the primers were designed and synthesized, then the splice variant of COX-2 in human myometrium from woman in labor was identified, cloned into vector and sequenced. RESULTS: The results showed that (1) The Expression of COX-2 mRNA was lower in human myometrium obtained from women who were not in labor than those in labor. (2) A new band of COX-2 was obtained in myometrium from a woman in labor. The fragment includes an unspliced intron, which locates between exons 7 and 8. CONCLUSION: COX-2 gene is not only expressed highly in human myometrium from women in labor, but also produced splicing variant by alternative splicing.

Adult↗
PubMed2003

[Effects of repeated body position change training for human orthostatic tolerance].

OBJECTIVE: To verify the validity that repeated position change training can increase human orthostatic tolerance and to explore its mechanism. METHOD: Six subjects were trained with repeated position change for 11 d according to a protocol of alternative head-down and head-up tilts, each set of training lasted for about 35 min. Their orthostatic tolerances were determined before and after training. RESULT: Compared with the data before training, subjects' symptom scores during orthostatic tolerance test after training decreased significantly (4.50 +/- 1.05 vs. 2.83 +/- 1.60, P<0.05), magnitude of the increased heart rate increase lowered significantly [(29.3 +/- 4.3) bpm vs. (13.5 +/- 7.5) bpm, P<0.01], magnitude of mean arterial blood pressure augmentation increased significantly [(4.8 +/- 4.4) mmHg vs. (9.0 +/- 3.0) mmHg, P<0.05] and cardiovascular response index decreased significantly (34.42 +/- 5.00 vs. 22.33 +/- 8.27, P<0.01). In brief, the responses to orthostatic stress were improved after training. CONCLUSION: Repeated alternative body position change training can increase human orthostatic tolerance. This kind of training is promising for pilot, especially astronaut training.

Adaptation, Physiological↗