Biomedical subjects

Song Xu

Publications and source records attributed to Song Xu.

9 recordsLinked to original sources

PubMed2025

Genome-wide association study reveals that TaODORANT1 negatively contributes to thousand grain weight by affecting starch synthesis in wheat.

Thousand grain weight (TGW) is one of the most important factors that control grain weight and crop yield. To date, dozens of wheat genes related to TGW have been isolated; however, the underlying molecular mechanisms governing grain development in wheat (Triticum aestivum) remain largely unknown. Benefiting from whole-genome resequencing and genome-wide association study, we identified an R2R3-type myeloblastosis (MYB) transcription factor, TaODORANT1, which was tightly associated with TGW. TaODORANT1 was specifically and highly expressed during the wheat grain developing stage. Knockout of TaODORANT1 led to an increase in TGW and starch content, as well as affected the expression of starch synthesis-related genes. Loss of function of TaODORANT1 altered the molecular structure and physiochemical properties of grain starch. Haplotype analysis showed that favorable Hap IV of TaODORANT1-A and favorable Hap I of TaODORANT1-B were significantly associated with the production of larger grains and higher TGW, respectively. Moreover, TaODORANT1 was a crucial targeted gene continuously selected in wheat domestication and breeding, and its orthologous genes might have retained similar functions in response to grain development. Our results highlight the importance of TaODORANT1 in affecting TGW, presenting potential targets for improving yield in wheat.

Triticum↗

PubMed2006

Reversible stimuli-responsive nanostructures assembled from amphiphilic block copolymers.

We present a novel route to assemble perpendicular cylinders by converting an asymmetric diblock copolymer from poly(styrene-b-tert-butyl acrylate) (PS-b-PtBA) to poly(styrene-b-acrylic acid) (PS-b-PAA) using an autocatalytic reaction. Upon exposure of the films of PS-b-PAA to water, PAA cylinders constrained by the continuous, glassy PS phase protrude 10 nm above the surface and swell laterally to form mushroom caps, rendering the entire surface hydrophilic. Upon annealing, the original nanostructures re-form demonstrating reversibility of swelling. Because of their stimuli-responsive behavior, these nanoscale materials are excellent candidates for sensors and microfluidic applications.

Acrylates↗

PubMed2006

[An optimized method for construction of genomic library].

Construction of genomic libraries is basic and important. Because of the laboriousness and high background of traditional methods for constructing genomic libraries, we improved them by overcoming these disadvantages. Two Ear I sites were chosen as the cloning sites, which can produce variable 3-base cohesive ends. Therefore the two overhangs could be devised to prevent a match and to avoid self-ligation of vector. Genomic DNA is cleaved partially with Sau3A I and subsequently incubated with dGTP and Klenow fragment of DNA polymerase Iso the self-ligation of fragments and ligation between them are blocked. In this study, the ARS probe vector (pHBM803/Trp) based on the improved method was constructed and then we constructed the Oryza sativa genomic library separately with the traditional method and improved method and compared them. The result of experiment indicated that the improved method could optimize the quality of library.

Cloning, Molecular↗

PubMed2005

A novel immunostimulator, N-[alpha-O-benzyl-N-(acetylmuramyl)-L-alanyl-D-isoglutaminyl]-N6-trans-(m-nitrocinnamoyl)-L-lysine, and its adjuvancy on the hepatitis B surface antigen.

N(2)-[alpha-O-benzyl-N-(acetylmuramyl)-L-alanyl-D-isoglutaminyl]-N(6)-trans-(m-nitrocinnamoyl)-L-lysine (muramyl dipeptide C, or MDP-C) has been synthesized as a novel, nonspecific immunomodulator. The present study shows that MDP-C induces strong cytolytic activity by macrophages on P388 leukemia cells and cytotoxic activity by cytotoxic T lymphocytes (CTLs) on P815 mastocytoma cells. Our results also indicate that MDP-C is an effective stimulator for production of interleukin-2 and interleukin-12 by murine bone marrow derived dendritic cells (BMDCs) and production of interferon-gamma by CTLs. Additionally, MDP-C increases the expression levels of several surface molecules, including CD11c, MHC class I, and intercellular adhesion molecule-1 in BMDCs. Moreover, MDP-C remarkably enhances the immune system's responsiveness to hepatitis B surface antigen (HBsAg) in hepatitis B virus transgenic mice for both antibody production and specific HBsAg T-cell responses ex vivo. Our results indicate that MDP-C is an apyrogenic, nonallergenic, and low-toxicity immunostimulator with great potential for diagnostic, immunotherapeutic, and prophylactic applications in diseases such as hepatitis B and cancers.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed2004

Solution-phase reductive cyclization of 2-quinoxalinol analogs: systematic study of parallel synthesis.

1,5-Difluoro-2,4-dinitrobenzene starting material was treated via primary and/or secondary substitution with a variety of amino acids or amines and the aromatic m-dinitro groups were then reductively cyclized provide the 2-quinoxalinol analogs. The conditions for 1,5-dialkylamino-2,4-dinitrobenzene reduction have been systematically studied and optimized in solution. Three effective methods are described for the high-throughout generation of 2-quinoxalinol analogs.

Biochemistry↗

PubMed2004

[Advances in pathogenesis and treatment of diabetic erectile dysfunction].

Erectile dysfunction is a familiar complication of diabetes mellitus, which results from combined factors of impairment to the vascular structure of the penis, the pathological changes in neural system and neural transmitters, and endocrine disorders. There are numerous therapeutic options for the treatment of diabetic erectile dysfunction, including medicines like PDE5 inhibitors, insulin, androgen, surgical therapy and gene therapy.

Androgens↗

PubMed2004

[Combined therapy for the chronic pelvic pain syndrome].

OBJECTIVE: To study the clinical diagnosis and treatment of the chronic pelvic pain syndrome (CPPS). METHODS: According to National Institute Health (NIH) classification, 165 cases of chronic prostatitis were surveyed by analysis of their laboratory results and clinical history. In addition, the chronic prostatitis symptom index (CPSI) of each patient was evaluated. All patients were treated for 6 to 8 weeks, type III A with antibiotics and alpha1 receptor inhibitor, type III B with alpha1 receptor inhibitor, diazepam diclogenatis and other narcotics. All cases were additionally treated by psychological and physical therapies. Traditional Chinese Medicine was also used in some cases. RESULTS: Based on the results of CPSI after 6 weeks treatment, 121 (73.3%) significantly improved, 26 (15.8%) slightly improved and only 18(10.9%) did not respond to the therapy. CONCLUSION: Combined therapy can be an effective treatment for the chronic pelvic pain syndrome.

Adolescent↗

PubMed2002

[Synthesis of 4-, 6- or 7-substituted phenyliminomethylenecoumarins and their anticancer activities].

AIM: A series of substituted phenyliminomethylenecoumarins derivatives was designed in order to find compounds possessing anticancer activities. METHODS: Title compounds (1a-b, 2a-b and 3a-q) were synthesized and screened by several anticancer models in vitro. RESULTS: Twenty-one new compounds (1a-b, 2a-b and 3a-q) were synthesized and screened. Structures of the new compunds were determined by MS, HNMR and elemental analysis. Twelve compounds (3c, 3d, 3e, 3f, 3g, 3h, 3j, 3k, 3m, 3o, 3p, 3q) showed inhibitory effects on HCT-8, KB and Bel7402 cell lines in vitro. CONCLUSION: Some compounds had certain anticancer activities and were worth further studying.

Antineoplastic Agents↗

PubMedDate not supplied

Parallel approach for solution-phase synthesis of 2-quinoxalinol analogues and their inhibition of LPS-induced TNF-alpha release on mouse macrophages in vitro.

A parallel solution-phase synthesis of 2-quinoxalinol analogues is described. The key step-simultaneous reductions of m-Ar(NO2)2 to m-Ar(NH2)2 was investigated extensively. We obtained preliminary pharmacological activity of those analogues for the inhibition of LPS-induced TNF-alpha release on mouse macrophage in vitro. Two compounds revealed inhibitory activity, with IC50 values of 0.40 microM (7-amino-6-[(3-methoxypropyl)amino]-3-methyl-2-quinoxalinol) and 2.2 microM (7-amino-6-[(3-butoxypropyl)amino]-3-methyl-2-quinoxalinol), respectively.

Animals↗