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Biomedical subjects

Feng Pan

Publications and source records attributed to Feng Pan.

35 records · Page 2Linked to original sources
PubMed2004

ARPC1/Arc40 mediates the interaction of the actin-related protein 2 and 3 complex with Wiskott-Aldrich syndrome protein family activators.

The actin-related protein 2 and 3 (Arp2/3) complex is a seven-subunit protein complex that nucleates actin filaments at the cell cortex. Despite extensive cross-linking, crystallography, genetic and biochemical studies, the contribution of each subunit to the activity of the complex remains largely unclear. In this study we characterized the function of the 40-kDa subunit, ARPC1/Arc40, of the yeast Arp2/3 complex. We showed that this subunit is indeed a stable component of the Arp2/3 complex, but its highly unusual electrophoretic mobility eluded detection in previous studies. Recombinant Arc40 bound the VCA domain of Wiskott-Aldrich syndrome protein family activators at a K(d) of 0.45 mum, close to that of the full complex with VCA (0.30 microm), and this interaction was dependent on the conserved tryptophan at the COOH terminus of VCA. Using a newly constructed Delta arc40 yeast strain, we showed that loss of Arc40 severely reduced the binding affinity of the Arp2/3 complex with VCA as well as the nucleation activity of the complex, suggesting that Arc40 contains an important contact site of the Arp2/3 complex with VCA. The Delta arc40 cells exhibited reduced growth rate, loss of actin patches, and accumulation of cables like actin aggregates, phenotypes typical of other subunit nulls, suggesting that Arc40 functions exclusively within the Arp2/3 complex.

Actin-Related Protein 2↗
PubMed2004

Algebraic solutions of an extended pairing model for well deformed nuclei.

A Nilsson mean-field plus extended pairing interaction Hamiltonian with many-pair interaction terms is proposed. Eigenvalues of the extended pairing model are easy to obtain. Our investigation shows that one- and two-body interactions continue to dominate the dynamics for relatively small values of the pairing strength. As the strength of the pairing interaction grows, however, the three- and higher many-body interaction terms grow in importance. A numerical study of even-odd mass differences in the (154-171)Yb isotopes shows that the extended pairing model is applicable to well deformed nuclei.

Journal Article↗
PubMed2004

Application of the nonlinear crystal SrB4O7 for ultrafast diagnostics converting to wavelengths as short as 125 nm.

We used non-phase-matched second-harmonic generation (SHG) in the highly nonlinear but low-birefringence crystal SrB4O7 for temporal characterization (autocorrelation) of femtosecond UV pulses to convert these pulses to wavelengths as low as 125 nm, close to the transparency limit of SrB4O7. The sensitivity of this method was approximately 1 microJ at the fundamental for a repetition rate of 1 kHz. We also used SHG at longer wavelengths to estimate the three nonlinear coefficients of SrB4O7.

Journal Article↗
PubMed2004

Osmotic stress of salmon stimulates upregulation of a cold inducible RNA binding protein (CIRP) similar to that of mammals and amphibians.

Salmon are subjected to hyperosmotic stress during transition from freshwater to the marine environment. A variety of mechanisms have evolved to allow movement of the animal from a hydrating to a dehydrating environment. Using differential assay of mRNA expression, a 1.3 kb transcript was found to be upregulated in branchial lamellae of salmon exposed to hyperosmotic conditions. The transcript contains an open reading frame of 618 nt coding for a 205 amino acid protein with a molecular mass of 21.5 kDa. The putative protein, dubbed salmon glycine-rich RNA binding protein (SGRP), possesses a high degree of identity (>70%) with the cold inducible RNA binding proteins (CIRP) of mammals and amphibians and contains the canonical features of these proteins including a single RNA recognition motif (RRM), high glycine content and conserved flanking motifs. SGRP mRNA was observed to increase in response to hyperosmotic stress of branchial tissue with maximum levels of expression after 48 h of exposure. Transcript also was observed in liver, kidney and heart but was not upregulated significantly by osmotic stress in these tissues. Exposure of isolated lamellae to heat stress and sodium arsenite, known inducers of hsps, did not stimulate accumulation of SGRP transcript. Similarly, inhibition of protein synthesis with cycloheximide and the MAPK and MEK signal transduction pathways with SB202190 and PD98059 failed to alter expression of the gene. Of significance was the absence of an increase in expression of SGRP in response to cold stress (DeltaT = 5 and 12 degrees C for 12 and 24 h). The findings of this research suggest that ectothermic salmon inhabiting boreal waters possess a protein analogous to the CIRPs currently identified in mammals and amphibians. In contrast to the function of CIRPs, SGRP appears to have a more prominent role in adaptation to hyperosmotic conditions rather than cold stress.

Amino Acid Sequence↗
PubMed2004

Biodegradation of polycyclic aromatic hydrocarbons by Pichia anomala.

Pichia anomala 2.2540, isolated from soil contaminated by crude oil, degraded naphthalene, dibenzothiophene, phenanthrene and chrysene, both singly and in combination. The yeast degraded 4.5 mg naphthalene l(-1) within 24 h. Phenanthrene was degraded after a lag of 24 h. When a mixture of all four polycyclic aromatic hydrocarbons was treated at either 0.1-1.6 mg l(-1) or 3.1-5.3 mg l(-1), naphthalene was completely degraded first within 24 h, followed by phenanthrene and dibenzothiophene after 48 h. Chrysene, which remained in the mixture even after 96 h, could be degraded along with naphthalene. Chrysene at 0.7 and 1 mg l(-1), in the presence of 4.3 and 65 mg naphthalene l(-1), respectively, was removed within 96 h.

Biodegradation, Environmental↗
PubMed2004

[Clinical observation on treatment of gastro-esophageal reflux with modified zhizhu pill].

OBJECTIVE: To observe the therapeutic effect of modified Zhizhu pill (ZZP) in treating gastro-esophageal reflux disease (GERD) and to explore its mechanism. METHODS: Sixty-three GERD patients were randomly divided into the treated group (n = 30) and the control group (n = 33). The treated group was treated with ZZP 100 ml, twice daily by orally taking half an hour before meal. The control group was treated with Ranitidine 0.15 g, twice daily and Cisapride 10 mg, three times a day by orally taking before meal. The therapeutic course for both groups was 8 weeks. The changes of symptom scoring, endoscopic examination, esophageal pressure, 24 hrs monitoring on pH and blood level of motilin in the two groups were recorded and compared. RESULTS: After treatment, the symptom scoring, esophageal pressure, 24 hrs monitoring on pH and blood motilin level were improved in both groups (P < 0.05), and the improvement in the treated group was more significant than that in the control group (P < 0.05). CONCLUSION: ZZP has good effect in treating GERD.

Adult↗
PubMed2004

[Role of dendritic cells in the pathogenesis of asthma in children].

UNLABELLED: Dendritic cells (DC) are very potent antigen-presenting cells (APC) with a unique ability to activate naive T cells to induce the differentiation of TH1/TH2. Monocytes can develop into DC in the presence of different cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. DCs are thought to play a key role in the initiation and maintenance of T cell immunity to inhaled antigens. While the density of DC within the bronchial mucosa is increased in asthma, there is little information currently available concerning the effects of DC in asthmatic children. OBJECTIVE: To investigate the role of dendritic cells in the pathogenesis of acute attack of asthma in children. METHODS: Thomas' method was adopted. The adherent precursors of DC were isolated from peripheral blood of asthmatic children in acute attack stage and healthy controls. The adherent cells were induced with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha) to DC in vitro. The expression of the surface molecules CD80, CD86, HLA-DR etc. on the DC was examined by fluorescent activated cell sorter (FACS). And the ability to secret IL-10, IL-12 and their potentials to stimulate the proliferative reaction of DC inductive self T- lymphocyte were observed. RESULTS: The results showed that in asthmatic children's acute attack stage, self T- lymphocyte proliferative reaction induced by DC was remarkably increased compared with normal control subjects (P < 0.01). At the same time, the asthmatic children in acute attack stage had remarkably decreased the ability to secret IL-10 compared with normal control subjects (P < 0.01), while the ability to secret IL-12 remarkably decreased compared with normal control subjects (P < 0.01); meanwhile, the HLA-DR and co-stimulating factor CD86(B(7-2)) expressed by DCs remarkably increased in the asthmatic children in acute attack stage compared with normal control subjects (P < 0.01). CONCLUSION: DC possibly plays a vital role in the immunological mechanism of asthma by means of inducing the differentiation of TH1/TH2, that is DC may be the key factor in initiating the airway allergic reaction and the possible mechanism may involve interleukins (especially IL-10 and IL-12, etc.) secreted by DCs.

Adolescent↗
PubMed2003

A non-linear optical crystal, Cd(3)Zn(3)(BO(3))(4).

The title compound, tricadmium trizinc tetraborate, Cd(3)Zn(3)(BO(3))(4), is a new non-linear optical (NLO) crystal and its structure has been determined by single-crystal X-ray diffraction. This compound is composed of planar [BO(3)](3-) groups sharing O atoms with CdO(4) or ZnO(4) tetrahedra. The BO(3) triangles are located on threefold axes and are arranged with nearly the same orientation. The Cd and Zn atoms are disordered on the same site in the proportion 1:1. A strong second harmonic generation of Nd:YAG laser radiation (lambda = 1064 nm) has been observed for a crystal of the title compound.

Journal Article↗
PubMed2003

Active transport of the survival motor neuron protein and the role of exon-7 in cytoplasmic localization.

Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by deletion and/or mutation of the survival motor neuron protein Gene (SMN1) that results in the expression of a truncated protein lacking the C terminal exon-7. Whereas SMN has been shown to be an important component of diverse ribonucleoprotein (RNP) complexes, its function in neurons is unknown. We hypothesize that the active transport of SMN may be important for neurite outgrowth and that disruption of exon-7 could impair its normal intracellular trafficking. SMN was localized in granules that were associated with cytoskeletal filament systems and distributed throughout neurites and growth cones. Live cell imaging of enhanced green fluorescent protein (EGFP)-SMN granules revealed rapid, bidirectional and cytoskeletal-dependent movements. Exon-7 was necessary for localization of SMN into the cytoplasm but was not sufficient for granule formation and transport. A cytoplasmic targeting signal within exon-7 was identified that could completely redistribute the nuclear protein D-box binding factor 1 into the cytoplasm. Neurons transfected with SMN lacking exon-7 had significantly shorter neurites, a defect that could be rescued by redirecting the exon-7 deletion mutant into neurites by a targeting sequence from growth-associated protein-43. These findings provide the first demonstration of cytoskeletal-based active transport of SMN in neuronal processes and the function of exon-7 in cytoplasmic localization. Such observations provide motivation to investigate possible transport defects or inefficiency of SMN associated RNPs in motor neuron axons in SMA.

Actin Cytoskeleton↗
PubMed2003

[The purification and isolation of a new type of rabbit-origin lipopolysaccharide binding protein and the study of its biological function in vitro].

OBJECTIVE: To isolate and purify a new type of lipopolysaccharide binding protein (LBP) from burn rabbit serum, and to investigate its biological functions. METHODS: Rabbits subjected to burn injury and endotoxemia were employed. The serum from the rabbits was purified by two-steps of ion-exchange chromatography (Bio-Rex 70 Resin, Mono-Q) and gel chromatography. Furthermore, the serum was identified by flow cytometry analysis, agglomeration test with sheep erythrocyte, and amino end amino acid residue sequencing. The obtained protein was applied to cultured human monocytes (U937), and the cytokine secretion such as TNFalpha from the U937 was observed. RESULTS: The molecular weight of the harvested protein was 48 kDa, and the 10 amino acid sequence at N end was arranged as GSQGTFTSEE, which was different to the amino acid sequence in NCBI protein bank and was so named P48. P48 possessed similar function to that of LBP and could promote the binding of LPS in a very low concentration with peripheral blood monocytes (PBMC), and also promote the TNFalpha secretion from U937. CONCLUSION: P48, a new type of LBP, could be isolated and purified from the burn rabbit serum. P48 possessed similar biological activities to that of LBP and could promote the process of inflammatory reaction.

Acute-Phase Proteins↗
PubMed2003

[Activation of nuclear factor kappa B in newborn rats sepsis].

OBJECTIVE: The aim of the study is to explore the effect of NF-kappa B signal pathway in neonatal sepsis so as to provide the experimental base for corresponding clinical treatment of the sepsis, in which NF-kappa B is taken as the target. METHODS: The sepsis model was established in newborn rats by giving Staphylococcus aureus subcutaneously: (1) The electrophoretic mobility shift assay (EMSA) was used to observe the activity of NF-kappa B in the lungs and the livers in newborn rats with Staphylococcus aureus sepsis. (2) Immunohistochemical method was used to observe the activity of NF-kappa B P56 in newborn rats with Staphylococcus aureus sepsis. (3) The anti-oxidant pyrrolidine dithiocarbamate (PDTC) was used to observe its effect on NF-kappa B activities of liver and lungs and on the activity of splenic NF-kappa B P56 in newborn rats with Staphylococcus aureus sepsis. RESULTS: In newborn rats with Staphylococcus aureus sepsis, the NF-kappa B activity in lungs was enhanced at the 1st hour and reached to the peak level at the 3rd hour; then, it was weakened gradually and at the 24th hour faded away. The activity of the liver NF-kappa B was also activated and peaked at the 4th hour; then, it was gradually weakened and at the 24th hour faded away. The positive expression of splenic NF-kappa B P56 began to be intensified at the 1st hour (12.0 +/- 3.7), peaked at the 3rd hour (51.4 +/- 5.9) and showed insignificant differences at the 24th hour (3.4 +/- 1.4) as compared with the sepsis group. PDTC had an inhibitive effect on the activities of liver NF-kappa B and lung NF-kappa B and on the positive expression of splenic NF-kappa B P56 used in the dosage of 50-200 mg/kg. The larger the dosage was used, the more intensified inhibitive effect could be obtained. In the dosage of 200 mg/kg, the inhibitive effect was the most intensified. CONCLUSIONS: (1) In newborn rats with Staphylococcus aureus sepsis, the NF-kappa B of lungs, liver and spleen were activated, and all indicate a peak. (2) The anti-oxidant PDTC can inhibit NF-kappa B activity in a dose-effect fashion in newborn rats with Staphylococcus aureus sepsis.

Animals↗
PubMed2002

A predominantly nuclear protein affecting cytoplasmic localization of beta-actin mRNA in fibroblasts and neurons.

The localization of beta-actin mRNA to the leading lamellae of chicken fibroblasts and neurite growth cones of developing neurons requires a 54-nt localization signal (the zipcode) within the 3' untranslated region. In this study we have identified and isolated five proteins binding to the zipcode. One of these we previously identified as zipcode binding protein (ZBP)1, a 4-KH domain protein. A second is now investigated in detail: a 92-kD protein, ZBP2, that is especially abundant in extracts from embryonic brain. We show that ZBP2 is a homologue of the human hnRNP protein, KSRP, that appears to mediate pre-mRNA splicing. However, ZBP2 has a 47-amino acid (aa) sequence not present in KSRP. Various portions of ZBP2 fused to GFP indicate that the protein most likely shuttles between the nucleus and the cytoplasm, and that the 47-aa insert promotes the nuclear localization. Expression of a truncated ZBP2 inhibits the localization of beta-actin mRNA in both fibroblast and neurons. These data suggest that ZBP2, although predominantly a nuclear protein, has a role in the cytoplasmic localization of beta-actin mRNA.

Actins↗
PubMed2002

A homolog of the E3 ubiquitin ligase Rbx1 is induced during hyperosmotic stress of salmon.

Juvenile salmon migrating from freshwater to the marine environment confront a marked change in environmental osmolality. Using differential display of mRNA expression, we cloned a 1.9-kb cDNA upregulated in isolated tissues of salmon exposed to the hyperosmotic stress associated with transition to the dehydrating marine environment. The cDNA codes for a 21-kDa protein, salmon hyperosmotic protein 21 (Shop21), with 98% identity to Rbx1, an E3 ubiquitin ligase; the protein also contains a novel 81-amino acid domain at the NH(2) terminus not found in Rbx1. Moderate hyperosmotic stress (24 h at 550 mosmol/kg) increased Shop21 transcript 10-fold in branchial lamellae, whereas no upregulation was observed under more severe stress (> or = 800 mosmol/kg). Expression of the gene also was observed in heart and kidney. Replacement of NaCl with mannitol, but not glycerol, also elicited an increase in Shop21 mRNA. Inhibition of the mitogen-activated protein kinase and mitogen-activated extracellular regulated kinase kinase signal transduction pathways failed to blunt the Shop21 response during hyperosmotic stress. Shop21 mRNA also accumulated during thermal stress but to a lesser extent than heat shock protein 70 mRNA. The potential importance of Shop21 to the living animal is suggested by marked upregulation of the gene in salmon after transfer to seawater. The results of these investigations suggest that Shop21 may have a role in targeting selected proteins (e.g., in freshwater ionocytes) nonessential for adaptation to seawater for removal via the proteasome pathway.

Adaptation, Physiological↗
PubMed2002

[Nitrification of high concentration NH4(+)-N in membrane bioreactor].

Nitrification performance of a membrane bioreactor was investigated under high concentration of NH4(+)-N. The removal rate of NH4(+)-N was over 99% under the condition of influent NH4(+)-N of 2000 mg/L and volumetric loading rate of NH4(+)-N 2.0 kg/(m3.d). The specific nitrification rate was kept to be 0.36/d in a period of half year.

Ammonia↗
PubMed1998

Cloning of DNA Fragments Possessing Promoter Function from Kluyveromyces cicerisporus.

Using three yeast promoter-probe plasmids pSK-kan401, pSK-kan1105, pSK-kan1238 with different reading frames, eight DNA fragments possessing high efficient promoter function have been cloned from K. cicerisporus. Their 3'-DNA sequences have been analyzed. The relative strength of their promoter function was studied by comparing their ability to promote the expression of the reporter gene APHI with that of glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) promoter in K. lactis. The results showed that the insertion fragments in pSK-kan401-41 and pSK-kan1105-51 have stronger promoter function and they are also functional in K. cicerisporus Y179.

Journal Article↗
PubMed1998

Cloning of GAP Gene from K. fragilis.

The K. fragilis CBS 397 gene library was screened with a GAP probe, which was designed according to the homology with S. cerevisiae, K. lactis, K. marxianus GAP gene. One positive clone pG1 containing GAP1 gene was isolated and confirmed by Southern hybridization. The GAP1 gene was partially sequenced. By using a fragment of the clone as a probe, another positive clone pG2 was acquired and also confirmed by Southern hybridization. The GAP2 gene from pG2 was completely sequenced. The upstream sequences of both genes were shown to have promoter activity. The fragment of pG1 could hybridize with three chromosomes of K. fragilis.

Journal Article↗