Optical dephasing by a random telegraph frequency modulation.
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Journal Article↗
Biomedical subjects
S Huang
Publications and source records attributed to S Huang.
The Arabidopsis profilin gene family. Evidence for an ancient split between constitutive and pollen-specific profilin genes.
Profilin is a ubiquitous eukaryotic protein that regulates the actin cytoskeleton and recently has been identified as a potent allergen in pollen. We examined the profilin gene family in the model plant, Arabidopsis thaliana, and found that it contained approximately 8 to 10 members. Four distinct profilin sequences, three cDNAs, PRF1, PRF2, and PRF3, and two genomic clones, PRF1 and PRF4, were isolated and characterized. These genes encoded four distinct profilin isoforms of 131 to 134 amino acids. Northern and reverse-transcriptase polymerase chain reaction analyses demonstrated that Arabidopsis PRF1 was expressed in all major plant organs, whereas PRF4 was specifically expressed in mature pollen. Gene trees constructed from amino acid sequence data revealed the presence of two ancient, distinct profilin gene classes in plants. PRF4 was in a class with previously identified pollen-specific profilins from monocot and dicot species. PRF1, PRF2, PRF3, and a distant dicot sequence formed a separate novel class, suggesting an ancient separation of plant profilins based on regulation and perhaps function. The coevolution of plant actin and profilin classes with similar patterns of expression is discussed. The similarity of plant, fungal, protist, insect, and nematode profilins and their extreme divergence from the vertebrate profilins has striking implications for the evolution of fungal-spore- and plant-pollen-profilins as allergens.
Allergens↗
The arabidopsis ACT7 actin gene is expressed in rapidly developing tissues and responds to several external stimuli.
ACT7 encodes one of the six distinct and ancient subclasses of actin protein in the complex Arabidopsis actin gene family. We determined the sequence and structure of the Arabidopsis thaliana ACT7 actin gene and investigated its tissue-specific expression and regulation. The ACT7 mRNA levels varied by 128-fold among several different tissues and organs. The highest levels of aCT7 mRNA were found in rapidly expanding vegetative organs, the lowest in pollen. A translational fusion with the 5' end of ACT 7 (1.9 kb) joined to the beta-glucuronidase reporter gene was strongly and preferentially expressed in all young, developing vegetative tissues of transgenic Arabidopsis plants. ACT7 was the only Arabidopsis actin gene strongly expressed in the hypocotyl and seed coat. Although no beta-glucuronidase expression was seen in developing ovules or immature seeds, strong expression was seen in dry seeds and immediately after imbibition in the entire seedling. ACT7 was the only Arabidopsis actin gene to respond strongly to auxin, other hormone treatments, light regime, and wounding, and may be the primary actin gene responding to external stimuli. The ACT7 promoter sequence contains a remarkable number of motifs with sequence similarity to putative phytohormone response elements.
Actins↗
Conserved expression of the Arabidopsis ACT1 and ACT 3 actin subclass in organ primordia and mature pollen.
We have proposed that ancient and divergent classes of plant actin genes have been preserved throughout vascular plant evolution, because they have distinct patterns of gene regulation. The hypothesis was explored for ACT1 and ACT3, which represent one of the six ancient subclasses in the Arabidopsis actin gene family. Comparison of ACT1 and ACT3 cDNA and genomic sequences revealed highly divergent flaking and intron sequences, whereas they encoded nearly identical proteins. Quantification of their level of divergence suggests that they have not shared a common ancestor for 30 to 60 million years. Gene-specific RNA gel blot hybridization and reverse transcriptase-polymerase chain reaction analyses demonstrated that the distribution of ACT1 and ACT3 mRNAs was very similar: both preferentially accumulated at high levels in mature pollen and at very low levels in the other major organs. The 5' flanking regions of both genes, including the promoter, leader exon and intron, and the first 19 condons, were fused to the beta-glucuronidase (GUS) reporter gene. The expression of these reporter fusions was examined in a large number of transgenic Arabidopsis plants. Histochemical assays demonstrated that both ACT1-GUS and ACT3-GUS constructs were expressed preferentially in pollen, pollen tubes, and in all organ primordia, including those in roots shoots, and the inflorescence. Comparison of the 5' flanking regions of ACT1 and ACT3 revealed a number of short conserved sequences, which may direct their common transcriptional and post-transcriptional regulation. The expression patterns observed were distinct from those of any other other Arabidopsis actin subclass. The conservation of their expression pattern and amino acid sequences suggests that this actin subclass plays a distinct and required role in the plant cytoskeleton.
Actins↗
Fluoride distribution in human dental calculus obtained from different sites on the tooth surface.
We examined the site specificity of fluoride (F) distribution in human dental calculus. Teeth with supra- and subgingival calculus were obtained from patients who resided in non-fluoridated areas in Japan and China. Sequential layers of the dental calculus (30 microns thick) were abraded by an abrasive micro-sampling technique and fluoride and phosphorus in the powdered samples were analyzed. Fluoride concentrations were highest in the outer, lowest in the middle and intermediate in the inner layers of dental calculus in general. In the outermost layers fluoride concentrations were highest in calculus found near the tooth cervix both in supra- and subgingival calculus. Fluoride concentrations decreased markedly toward the apical region in subgingival calculus, while it did not change toward the incisal or occlusal region in supragingival calculus. In the inner layers, fluoride concentrations in both supra- and subgingival calculus were not affected by position on the teeth. Fluoride concentrations in subgingival calculus near the apex were lower than in supragingival calculus near the incisal or occlusal region. It was concluded that the fluoride concentrations differ in different regions of dental calculus, probably due to their different mechanisms of formation.
Calcium Phosphates↗
Adenovirus interaction with distinct integrins mediates separate events in cell entry and gene delivery to hematopoietic cells.
A major impediment to the effective use of adenovirus vectors for gene therapy is a lack of knowledge of how these vectors interact with diverse cell types in vivo. Adenovirus attachment to most human cell types is mediated by the fiber protein, which binds to an as yet unidentified cell receptor. In contrast to this, we report that adenovirus type 2 (Ad2) attachment to hematopoietic cells is facilitated by interaction of the penton base protein with members of the beta2 integrin family. Adenovirus particles were capable of binding to human monocytic cells, which lack fiber receptors, and virus binding could be blocked by a soluble penton base or by a function-blocking monoclonal antibody to integrin alphaMbeta2. To confirm the role of alphaMbeta2 integrins in Ad2 binding to hematopoietic cells, we analyzed virus attachment and gene delivery to CHO cells expressing recombinant beta2 integrins. alphaMbeta2-expressing CHO cells supported 3- to 5-fold-higher levels of Ad2 binding and 5- to 10-fold-larger amounts of gene delivery than did nontransfected CHO cells, indicating that alphaMbeta2 facilitates adenovirus attachment to and infection of hematopoietic cells. While beta2 integrins promote Ad2 attachment to hematopoietic cells, further studies demonstrated that alphav integrins were required for the next step in infection, virus internalization into cell endosomes. These studies reveal a novel pathway of Ad2 infection of hematopoietic cells mediated by distinct integrins which facilitate separate events in virus entry. They also suggest a possible strategy for selective adenovirus-mediated gene delivery to hematopoietic cells.
Adenoviruses, Human↗
Ascosteroside, a new antifungal agent from Ascotricha amphitricha. II. Isolation and structure elucidation.
The novel antifungal agent ascosteroside (1) was isolated from cultured broth of Ascotricha amphitricha (ATCC 74237). The structure based on spectroscopic data was determined to be an alpha-linked glycoside of a lanostane-type triterpenoid.
Antifungal Agents↗
Harziphilone and fleephilone, two new HIV REV/RRE binding inhibitors produced by Trichoderma harzianum.
During the screening of the natural products for their ability to inhibit the binding of REV (regulation of virion expression) protein to [33P] labeled RRE (REV responsive element) RNA, two novel fungal metabolites, harziphilone and fleephilone, were isolated from the butanol-methanol (1:1) extract of the fermentation broth of Trichoderma harzianum by bioassay guided fractionation. The structures of these two new compounds were established by spectroscopic methods. Harziphilone and fleephilone showed inhibitory activity against the binding of REV-protein to RRE RNA with IC50 values of 2.0 microM and 7.6 microM, respectively. However both compounds did not protect CEM-SS cells from acute HIV infection at concentration levels up to 200 micrograms/ml using an XTT dye reduction assay. In addition, harziphilone demonstrated cytotoxicity at 38 microM against the murine tumor cell line M-109.
Anti-HIV Agents↗
[Confirming the cause of inherited chronic chorea in Chinese patients].
OBJECTIVE: Huntington's disease (HD, known as inherited chronic chorea in China) is an autosomal dominant disorder. Almost all of the cases of inherited chronic chorea reported in the chinese literature were sporadic while about one-third of the HD families in foreign reports were related. To find out whether the gene defect responsible for inherited chronic chorea in Chinese is the same as that for Huntington's disease in Caucasians. METHOD: PCR method was employed to amplify the (CAG)n repeat sequence of the IT15 gene in normal Chinese and members of the families suffering from inherited chronic chorea in Chinese. RESULTS: The copy number of the repeats varied from 16 to 26 in 25 normal Chinese and increased significantly from 44 to 53 in 7 affected members from 4 families. CONCLUSION: It was confirmed for the first time at the gene level that the mechanism for inherited chronic chorea in Chinese is the same as that for Huntington's disease in Caucasians.
Adult↗
[Analysis of the A/C polymorphic site within the phenylalanine hydroxylase gene].
An A/C polymorphism was identified at nucleotide-11 from the acceptor site of IVS3 of the phenylalanine hydroxylase gene. This polymorphism can be detected easily by means of single strand conformation polymorphism analysis. The frequency for the majior allele (A) was 0.656 and 0.344 for the minor allele (C) with the PIC being 0.351 in Chinese population. There was no linkage disequilibrium between this site and the STR polymorphic site located upstream within the same intron of the gene. The ejjicincy of prenatal gene diagnosis fro PKU was estimated to be 78.1% by haplotype linkage analysis using these two polymorphic sits.
Humans↗
Interferon-gamma receptor-deficiency renders mice highly susceptible to toxoplasmosis by decreased macrophage activation.
Toxoplasma gondii may cause severe infections in immunocompromised patients including fetuses and those with AIDS. Among the factors mediating protection against T. gondii, IFN-gamma has gained special attention. To analyze the role of IFN-gamma in the early phase of toxoplasmosis, IFN-gamma receptor-deficient (IFN-gamma R0/0) mice were orally infected with low-virulent toxoplasms. IFN-gamma R0/0 mice died of the disease up to day 10 postinfection, whereas immunocompetent wild-type (WT) mice developed a chronic toxoplasmosis. Histopathology revealed that in IFN-gamma R0/0 mice, the parasite multiplied unrestrictedly in the small intestine, the intestinal lymphatic tissue, the liver, and the spleen. Ultimately, animals died of a necrotizing hepatitis. In WT mice, the same organs were effected, but multiplication of the parasite was effectively limited. Compared with WT mice, immunohistochemistry and flow cytometry demonstrated that in IFN-gamma R0/0 mice, macrophages were only marginally activated in response to the infection, as evidenced by a reduced expression of major histocompatability complex class II antigens. In addition, immunohistochemistry and RT-PCR showed a reduced production of the macrophage-derived cytokines tumor necrosis factor-alpha, inducible nitric oxide synthase, and IL-1 beta in the liver of IFN-gamma R0/0 mice. In contrast, activation of T cells, recruitment of immune cells to inflammatory foci, and anti-T. gondii IgM antibody production were unaffected by the mutation of the IFN-gamma R. Moreover, induction of IL-2, IL-4, and IL-10 mRNA transcripts in the liver was normal in IFN-gamma R0/0 mice. Adoptive transfer experiments revealed that the immune T cells of WT animals did not protect IFN-gamma R0/0 mice from lethal infection with highly virulent toxoplasms, whereas WT mice were significantly protected by the adoptive transfer. Based on these studies, we conclude that IFN-gamma is absolutely required for an efficient activation of macrophages. Macrophages are of critical importance in toxoplasmosis, and insufficient macrophage activation cannot be compensated by other immune mechanisms.
Adoptive Transfer↗
[A study of the variation of the (AT)xTy motif-530bp 5' to the beta-globin gene in the Chinese population].
The repeated purine-pyrimidine motif (AT)xTy at the region -530bp 5' to the beta-globin gene is regarded as the binding site for BP1, a transcriptionally repressive nuclear protein. In present study, the rearrangement patterns of the -530 motif in the Chinese population, including 43 patients with various hemoglobinopathies and part of their relatives (34), as well as 20 hematologically normal individuals, were investigated with the method of ds-DNA cycle sequencing. The results showed that the -530 motif in Chinese people had three major variation types-(AT)8T5, (AT)7T7 and (AT)9T5. Besides, a novel rearrangement type, (AT)10T3, was found in a hematologically normal family. Furthermore, the analysis of haplotype between the beta-globin structural loci and the -530 motif rearrangement indicated that linkage disequilibrium existed between three mutant beta-globin genes (i.e., IVS-II-654(C-->T), CD41-42(-4bp) and HbE), and three -530 motif rearrangement types (i.e., (AT)8T5, (AT)7T7 and (AT)9T5)7 respectively.
Asian People↗
[Detection of the mutational gene in phenylketonuria and prenatal diagnoses by using single strand conformation polymorphism methods].
OBJECTIVE: To establish rapid methods for the detection of gene mutations and prenatal diagnosis of phenylketonuria (PKU). METHODS: The single strand conformation polymorphism (SSCP) combined with silver staining technique were used to screen the mutations in the four exons of phenylalanine hydroxylase (PAH) gene. After the polymerase chain reaction, the DNA fragments were separated by electrophoresis on polyacrylamide gel containing glycerol and visualized by silver staining. RESULTS: Three known missense mutations which are R243Q (E7)[CGA(Arg243)-->CAA (Gln)], R413P(E12) [CGC(Arg413)-->CCC(Pro)] and Y356X(E11)[TAC(Tyr156)-->TAA(Ter)] were detected in 21 degrees C, 28 degrees C and 7 degrees C. Three kinds of unknown abnormal DNA bands in exon 10 were detected in 21 degrees C. The mutations of 13 PKU families have been detected. Prenatal gene diagnoses were successfully performed in 5 pregnancies at risk with PKU. CONCLUSION: The method is very useful for detecting the mutations and prenatal diagnoses of PKU families.
Exons↗
[Assay of contents of lysozyme, SIgA, IgA and IgG in tongue coating].
The contents of lysozyme, SIgA, IgA, and IgG in 98 cases with pathological tongue coating and 30 cases of normal coating were analysed by using the thorough random analysis of variance. The results showed that the content of lysozyme in pathological coating was lower than that in normals significantly (P < 0.0001), while the contents of SIgA, IgG in pathological coating were higher than that of normals (P < 0.0001). It indicates that immune reaction is very active during the development of pathological tongue coating.
Adolescent↗
[A study on methodology and the criteria for positive immunohistostaining of estrogen and progesterone receptors in paraffin embedded sections of breast cancer].
The expression of estrogen receptor (ER) and progesterone receptor (PR) in 200 breast cancer specimens were imvestigated by monoclonal antibody with S-P staining to evaluate and standardize the criteria for positive staining. The results revealed that the incidence of ER and PR were 73.5% and 65.5% respectively. The authors concluded that the immunostaining could demonstrate in situ ER and PR, the results were stable, highly sensitive, consistent and comparable with the well established and recognized techniques home and abroad. The authors further pointed out that the crucial point of the staining is antigen retrieval and reported the optimal temperature and the time of sodium citrate buffer treatment. In this report, the criteria for positive staining were discussed intensively. The observations indicated that the percentage of the positive cells is more reliable, representative and practical than that of positive staining intensity index.
Breast Neoplasms↗
[Early efficacy of recombinant human erythropoietin in treatment of anemia].
A Before-after study based on self-comparison was conducted to assess the early efficacy of recombinant human erythropoietin (r-HuEPO) in 51 patients with uremic anemia who were subjected to dialyses. A significant elevation of levels of Hb and Hct was observed (P < 0.001, P < 0.005) after r-HuEPO therapy. And hemorheologic tests showed whole blood viscosity was obviously increased (P < 0.005), but no changes in plasmic viscosity and platelet adhesion rate were found (P > 0.05). No increase of blood pressure of the patients was noticed in the early period after treatment. The results revealed a satisfactory early efficacy with few sideeffects of the r-HuEPO treatment in uremic anemia.
Adult↗
[Observation on TXB2 and 6-keto-PGF1 alpha in serum of patients with cor pulmonale].
To know the changes of TXA2 and PGI2 in serum of patients with cor pulmonale, the levels of their stable metabolites TXB2 and 6-keto-PGF1 alpha in serum were examined in 28 patients with cor pulmonale during alleviation, 29 patients with cor pulmonale during exacerbation before and after treatment and 10 healthy subjects. TXB2 and 6-keto-PGF1 alpha were 109.74 +/- 56.14 ng/L and 54.76 +/- 35.62 ng/L respectively in healthy subjects; TXB2/6-keto-PGF1 alpha = 2.004. The TXB2 level of patients with cor pulmonale at every stage was higher than that of healthy subjects (P < 0.05-0.01). Patients with cor pulmonale during exacerbation had the highest TXB2 level of 709.22 +/- 354.49 ng/L, which decreased to 408.24 +/- 289.41 ng/L (P < 0.05) after treatment with traditional Chinese medicine combined with western medicine and the decreased level as such was not significantly different from that during alleviation (333.14 +/- 324.14 ng/L). The 6-keto-PGF1 alpha level in patients with cor pulmonale at every stage was not significantly different from that of healthy subjects. Since TXB2 increased, the value TXB2/6-keto-PGF1 alpha of patients with cor pulmonale was greater than that of healthy subjects. It is most likely that chronic hypoxia and hypercapnia lead to prostaglandin release in the lung of patients with cor pulmonale; hypoxia and hypercapnia become more severe during exacerbation resulting from infection; which lead to increased prostaglandin release, then high TXB2 level ensue as the result. TXB2 decreases after amelioration of hypoxia during treatment. But the change of 6-keto-PGF1 alpha is not obvious.
6-Ketoprostaglandin F1 alpha↗
Modulation of chemosensitivity in human colon carcinoma cells by downregulating protein kinase C alpha expression.
Protein kinase C (PKC) is thought to play a role in tumor progression and drug resistance of colon carcinomas. Specifically, the PKC alpha isoform has been implicated in drug resistance and responsiveness of colon carcinoma cells to growth factors. Therefore, in this study we determined the effect of downregulating PKC alpha expression by transfecting human colon carcinoma cells with an antisense PKC alpha expression vector and then determined the sensitivity of these cells to the anticancer drugs mitomycin C (MMC), 5-fluorouracil (5-FU) and vincristine (Vin). Transiently transfecting the human colon carcinoma cell lines Moser, SW480 and HT29 with antisense PKC alpha expression vector (but not antisense PKC beta expression vector) consistently increased the sensitivity of these cells to MMC, 5-FU and VIN by several-fold. Sensitivity to these drugs was then further determined in the Moser colon carcinoma cell line stably transfected with antisense PKC alpha expression vector. This stably transfected cell line, which expressed a high level of antisense PKC alpha RNA with a concurrent reduction of PKC alpha protein expression, was found to exhibit an increased sensitivity to these anticancer drugs. Thus, strategies designed to downregulate PKC alpha expression may have potential in improving the responses of colon carcinoma cells to cytotoxic drugs.
Carcinoma↗