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Lin Tang

Publications and source records attributed to Lin Tang.

At least 19 recordsLinked to original sources
PubMed2026

R2R3-MYB transcription factor MYB113 specifically regulates anthocyanin accumulation in Lycium ruthenicum.

LrMYB113 drives anthocyanin biosynthesis in Lycium ruthenicum by forming an MBW complex and directly activating LrDFR and LrANS promoters, providing a genetic target for enhancing flavonoid production. Lycium ruthenicum Murray (black goji berry), a Solanaceae medicinal plant, is valued for its high flavonoid content. However, the transcriptional regulation of flavonoid biosynthesis in L. ruthenicum remains unclear, hindering its pharmaceutical development. Here, we identified and characterized LrMYB113, an R2R3-MYB transcription factor, as a key regulator of anthocyanin biosynthesis in L. ruthenicum. Phylogenetic analysis grouped LrMYB113 into the anthocyanin-associated S6 subgroup of MYBs. Heterologous expression of LrMYB113 in tobacco induced pigment accumulation and upregulated anthocyanin pathway genes. LrMYB113 overexpression in L. ruthenicum hairy roots enhanced accumulation of four acylated anthocyanins and activated anthocyanin pathway genes. Yeast two-hybrid and bimolecular fluorescence complementation assays showed LrMYB113 interacts with bHLHs (LrJAF13/LrAN1b) and WD40 (LrAN11) to form an MBW complex. Promoter binding and transactivation assays demonstrated LrMYB113 directly binds to and activates LrDFR and LrANS promoters. Dual-luciferase assays showed LrMYB113 alone strongly activates LrDFR and LrANS promoters; MBW complexes enhanced activity compared to individual bHLH/WD40 but not to LrMYB113 alone. Our findings identify LrMYB113 as a critical regulator of anthocyanin biosynthesis in L. ruthenicum, shedding light on flavonoid molecular mechanisms and supporting genetic improvement for pharmaceutical use.

Anthocyanins↗
PubMed2007

Hypoglycemia reduces the blood-oxygenation level dependent signal in primary auditory and visual cortex: a functional magnetic resonance imaging study.

Studies of the effects of hypoglycemia on the brain using neurocognitive testing have suggested that mainly complex functions subserved by secondary and tertiary cortex are affected by mild to moderate hypoglycemia and that intensively treated patients with Type I diabetes mellitus (T1DM) may have altered sensitivity to the central nervous system effects of hypoglycemia. Functional magnetic resonance imaging provides a sensitive, regionally-specific probe of possible neurophysiologic changes related to hypoglycemia in the brain. Eleven intensively-treated T1DM patients and 11 matched non-diabetic controls took part in a 2-day protocol in which functional magnetic resonance imaging (MRI) was used to measure changes in the patterns of brain activation produced by simple auditory and visual stimuli in different conditions. On one day, participants were euglycemic the entire time. On the other day, an initial 50-min euglycemic period was followed by a 50-min hypoglycemic period. Results indicated that hypoglycemia reduced the amplitude of the blood-oxygenation level dependent response in primary auditory and visual cortex to simple auditory and visual stimuli. The latency and duration of the transient hemodynamic response function were not affected. Responses to hypoglycemia were similar in diabetic and non-diabetic participants. These results suggest that mild to moderate hypoglycemia may alter the balance of blood flow and oxygen extraction when glucose levels are lowered. Intensively-treated T1DM, with its attendant frequent hypoglycemic episodes, did not seem to alter hypoglycemic responses in primary visual and auditory cortex.

Acoustic Stimulation↗
PubMed2006

Implantation Serine Proteinases heterodimerize and are critical in hatching and implantation.

BACKGROUND: We have recently reported the expression of murine Implantation Serine Proteinase genes in pre-implantation embryos (ISP1) and uterus (ISP1 and ISP2). These proteinases belong to the S1 proteinase family and are similar to mast cell tryptases, which function as multimers. RESULTS: Here, we report the purification and initial characterization of ISP1 and 2 with respect to their physico-chemical properties and physiological function. In addition to being co-expressed in uterus, we show that ISP1 and ISP2 are also co-expressed in the pre-implantation embryo. Together, they form a heterodimer with an approximate molecular weight of 63 kD. This complex is the active form of the enzyme, which we have further characterized as being trypsin-like, based on substrate and inhibitor specificities. In addition to having a role in embryo hatching and outgrowth, we demonstrate that ISP enzyme is localized to the site of embryo invasion during implantation and that its activity is important for successful implantation in vivo. CONCLUSION: On the basis of similarities in structural, chemical, and functional properties, we suggest that this ISP enzyme complex represents the classical hatching enzyme, strypsin. Our results demonstrate a critical role for ISP in embryo hatching and implantation.

Animals↗
PubMed2006

A hydroquinone biosensor using modified core-shell magnetic nanoparticles supported on carbon paste electrode.

A hydroquinone biosensor was developed and used to determine hydroquinone concentration in compost extracts based on the immobilization of laccase on the surface of modified magnetic core-shell (Fe(3)O(4)-SiO2) nanoparticles. Laccase was covalently immobilized on the magnetic nanoparticles by glutaraldehyde, which was modified with amino groups on its surface. The obtained magnetic bio-nanoparticles were attached to the surface of carbon paste electrode with the aid of a permanent magnet to determine hydroquinone. A good microenvironment for retaining the bioactivity of laccase was provided by the immobilization matrix. The linear range for hydroquinone determination was 1 x 10(-7) to 1.375 x 10(-4)M, with a detection limit of 1.5 x 10(-8)M. The current reached 95% of the steady-state current within about 60s. Hydroquinone concentration in compost extracts was determined by laccase biosensor and HPLC, the results of the two methods were approximately the same.

Biosensing Techniques↗
PubMed2006

Inferring direct regulatory targets from expression and genome location analyses: a comparison of transcription factor deletion and overexpression.

BACKGROUND: Effects on gene expression due to environmental or genetic changes can be easily measured using microarrays. However, indirect effects on expression can be substantial. The indirect effects of a perturbation need to be distinguished from the direct effects if we are to understand the structure and behavior of regulatory networks. RESULTS: The most direct way to perturb a transcriptional network is to alter transcription factor activity. Here, for the first time, we compare expression changes and genomic binding in a simple regulon under conditions of both low and high transcription factor activity. Specifically, we assessed the effects on expression and binding due to deletion of the yeast LEU3 transcription factor gene and effects due to elevation of Leu3 activity. Leu3 activity was elevated through overexpression and the introduction of a mutation that renders the protein constitutively active. Genes that are bound and/or regulated by Leu3 under one or both conditions were characterized in terms of their functional annotations and their predicted potential to be bound by Leu3. We also assessed the evolutionary conservation of the predicted binding potential using a novel alignment-independent method. Both perturbations yield genes that are likely to be direct targets of Leu3, including most of the classically defined targets. Additional direct targets are identified by each of the methods. However, experimental and computational criteria suggest that most genes whose expression is affected by the Leu3 genotype are unlikely to be regulated by binding of the protein. CONCLUSION: Most genes that are differentially expressed by Leu3 are not direct targets despite the exceptional simplicity of the regulon, and the unusually direct nature of the perturbations investigated. These conclusions are reached through computational analyses that support and extend chromatin immunoprecipitation data on the identities of direct targets. These results have implications for the interpretation of expression experiments, especially in cases for which chromatin immunoprecipitation data are unavailable, incomplete, or ambiguous.

2-Isopropylmalate Synthase↗
PubMed2006

Effects of different magnitudes of mechanical strain on Osteoblasts in vitro.

In addition to systemic and local factors, mechanical strain plays a crucial role in bone remodeling during growth, development, and fracture healing, and especially in orthodontic tooth movement. Although many papers have been published on the effects of mechanical stress on osteoblasts or osteoblastic cells, little is known about the effects of different magnitudes of mechanical strain on such cells. In the present study, we investigated how different magnitudes of cyclic tensile strain affected osteoblasts. MC3T3-E1 osteoblastic cells were subjected to 0%, 6%, 12% or 18% elongation for 24h using a Flexercell Strain Unit, and then the mRNA and protein expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) were examined. The results showed that cyclic tensile strain induced a magnitude-dependent increase (0%, 6%, 12%, and 18%) in OPG synthesis and a concomitant decrease in RANKL mRNA expression and sRANKL release from the osteoblasts. Furthermore, the induction of OPG mRNA expression by stretching was inhibited by indomethacin or genistein, and the stretch-induced reduction of RANKL mRNA was inhibited by PD098059. These results indicate that different magnitudes of cyclic tensile strain influence the biological behavior of osteoblasts, which profoundly affects bone remodeling.

Animals↗
PubMed2006

Crystal structure of human pyridoxal kinase.

Pyridoxal kinase, a member of the ribokinase superfamily, catalyzes the ATP-dependent phosphorylation reaction of vitamin B6 and is an essential enzyme in the formation of pyridoxal-5'-phosphate, a key cofactor for over 100 enzymes. Pyridoxal kinase is thus regarded as a potential target for pharmacological agents. In this paper, we report the 2.8 angstroms crystal structure of human pyridoxal kinase (HPLK) expressed in Escherichia coli. The diffraction data revealed unexpected merohedral perfect twinning along the crystallographic c axis. Taking perfect twinning into account, the structure in dimeric form was well refined according to the CNS program. Structure comparison reveals that the key 12-residue peptide over the active site in HPLK is a beta-strand/loop/beta-strand flap, while the corresponding peptide in sheep brain enzyme adopts a loop conformation. Moreover, HPLK possesses a more hydrophobic ATP-binding pocket. This structure will facilitate further biochemical studies and structure-based design of drugs related to pyridoxal kinase.

Adenosine Triphosphate↗
PubMed2006

Study of the disassembly-assembly process of alpha-synuclein fibrils by in situ atomic force microscopy.

In this report, we applied in situ atomic force microscopy (AFM) to study the dynamic process of disassembly-assembly of alpha-synuclein (alpha-Syn) fibrils in different solutions. Most of the mica-adsorbed alpha-Syn fibrils disassemble into small particles step-by-step on the mica surface in diluted solutions, yet a few short fibrils still extend to form longer fibrils. This process usually started randomly at the center of the long fibrils, which progressively disassemble into short fragments and small protein particles of varying size. Compared to disassembly, assembly happened infrequently when the protein concentration was low. It was observed directly by AFM that the chaotropic agent guanidinium chloride rapidly breaks the long alpha-Syn fibrils.

Microscopy, Atomic Force↗
PubMed2006

Composting of lead-contaminated solid waste with inocula of white-rot fungus.

The treatment of the simulated lead-contaminated solid waste by composting with white-rot fungus was studied at laboratory scale. The composting system without the inocula of white-rot fungus was prepared as control, and the composting of the uncontaminated solid waste with the inocula of white-rot fungus was carried out as the other control. The results indicated that the solid waste inoculated with white-rot fungus could be successfully processed. The final compost was mature with 70.5% of lead (Pb) in residual fraction and none in exchangeable fraction. Germination index reached 120%. All the results indicated that the bioavailability of Pb in compost was reduced and the potential harm of Pb in compost was alleviated by composting with the inocula of white-rot fungus.

Basidiomycota↗
PubMed2006

Stat1 expression is not sufficient to regulate the interferon signaling pathway in cellular immortalization.

DNA hypermethylation in gene promoters is an epigenetic mechanism regulating gene expression in cellular immortalization, an important step in carcinogenesis. Previously, we studied the genes dysregulated during immortalization using spontaneously immortalized fibroblasts from patients with Li-Fraumeni syndrome (LFS), who carry a germline mutation in the tumor suppressor gene p53. We found that multiple interferon (IFN) signaling pathway genes were regulated by epigenetic silencing. In this study we focused on a key regulator of that pathway, the signal transducer and transcription activator 1 (Stat1) gene. Although Stat1 is downregulated after cellular immortalization and upregulated in immortal MDAH041 cells after 5-aza-2'-deoxycytidine (5-aza-dC) treatment, we detected no methylation of the Stat1 promoter region in these cells before or after immortalization. To analyze the function of Stat1 in immortalization, we expressed Stat1 in immortal MDAH041 cells by stable infection, expecting to induce IFN-regulated genes or cellular senescence or both. However, the overexpression of Stat1 alone was not sufficient to repress the proliferation rate of immortal MDAH041 cells or induce senescence in immortal MDAH041 cells. We concluded that factor(s) additional to Stat1 (whether IFN dependent or not) are required for the immortalization of LFS fibroblasts.

Animals↗
PubMed2006

Expression profiling identifies three pathways altered in cellular immortalization: interferon, cell cycle, and cytoskeleton.

Abrogation of cellular senescence, resulting in immortalization, is a necessary step in the tumorigenic transformation of a cell. Four independent, spontaneously immortalized Li-Fraumeni syndrome (LFS) cell lines were used to analyze the gene expression changes that may have given these cell lines the growth advantage required to become immortal. A cellular senescence-like phenotype can be induced in immortal LFS cells by treating them with the DNA methyltransferase (DNMT) inhibitor 5-aza-deoxycytidine. We hypothesized, therefore, that genes epigenetically silenced by promoter methylation are potentially key regulators of senescence. We used microarrays to compare the epigenetic gene expression profiles of precrisis LFS cells with immortal LFS cells. Gene ontology analysis of the expression data revealed a statistically significant contribution of interferon pathway, cell cycle, and cytoskeletal genes in the process of immortalization. The identification of the genes and pathways regulating immortalization will lead to a better understanding of cellular immortalization and molecular targets in cancer and aging.

Azacitidine↗
PubMed2006

Applied radioactivity in radiation synovectomy with [188Re]rhenium sulfide suspension.

BACKGROUND: Early experience demonstrated absorbed dose in radiation synovectomy is about 100 Gy. For reaching this dose, the applied radioactivity should be calculated. METHOD: Twenty-nine synovitic models of rabbit were treated by intra-articular injection of [(188)Re]rhenium sulfide and histological changes of synovium and cartilage were examined. The applied radioactivity was calculated by method of absorbed dose factor. In clinical, eleven haemophilic patients with haemarthrosis were performed radiation synovectomy with treated [(188)Re]rhenium sulfide. The synovial thickness was evaluated by MR and its value was used to calculate the applied radioactivity. After radiation synovectomy, all patients were followed up by synovial thickness, regional inflammation, and clinical course including bleeding frequency. RESULTS: In rabbit models, the synovitic membrane can be eliminated by calculated radioactivity as planed without damaging the joint cartilage. In patients study, all patients exhibited significant reductions in synovial thickness and inflammation after radiation synovectomy with the planed radioactivities of [(188)Re]rhenium sulfide. Post-procedure bleeding frequency reduction in excellent and good reached to 63.6% by 18 months. In the cases of joint bleeding, the need for antihaemophilic factor treatment decreased immensely. Most of the recurrent episodes of bleeding were mild, subsiding with local means. CONCLUSION: The applied radioactivity in radiation synovectomy could be calculated according to thickness of inflamed synovium. Further study including comparison therapeutic results from calculated individual activities with results from fixed activities and long-term follow-up is warranted.

Adult↗
PubMed2006

[Promoter methylation and mRNA expression of APC gene in MCF10 breast cancer model].

OBJECTIVE: To investigate the promoter methylation status and mRNA expression of APC gene in MCF10 model of breast cancer progression. METHODS: Methylation specific PCR and sodium bisufite genomic sequencing were employed to detect the methylation status of APC promoter 1A in normal breast tissues, conventional breast cancer cell line MCF-7 and MCF10 model cell lines including MCF10A (breast hyperplastic cell line, non-tumorigenic), MCF10AT (pre-malignant cell lines, producing slowly progressing hyperplastic and dysplastic lesions), MCF10DCIS.com (breast ductal carcinoma in-situ cell line, producing ductal carcinoma in-situ), MCF10CA1a, MCF10CA1d, MCF10CA1h cell lines (invasive breast carcinoma cell line, forming aggressive tumors of different morphology and metastatic potential). In addition, mRNA expression of APC was determined by reverse transcriptase PCR and real-time PCR assays. RESULTS: Hypomethylation of APC promoter 1A was identified in hyperplastic cell line MCF10A, pre-malignant cell line MCF10AT, ductal carcinoma in-situ cell line MCF10DCIS.com, invasive carcinoma cell lines MCF10CA1a, MCF10CA1d, MCF10CA1h and normal breast tissue. MCF-7 showed partial methylation at the promoter. Statistically significant reduction of APC mRNA expression was not found in all MCF10 cell lines and MCF-7, compared with that of normal breast tissue (MCF10AT, MCF10CA1a, MCF10CA1d, MCF10CA1h and MCF10DCIS.com showed reduced mRNA expressions of APC at 0.27, 0.96, 1.78, 2.70, and 2.03 times respectively. MCF10A and MCF-7 even showed an increase of APC mRNA expression at 0.02 and 0.33 times, respectively). CONCLUSION: The aberrant promoter methylation of APC is not related to the breast cancer progression, at least in the MCF10 model system.

Adenomatous Polyposis Coli Protein↗
PubMed2006

[Screening the hALR-interacting protein from the cDNA library of hepatocarcinoma cells and studying its biological functions].

OBJECTIVES: To screen the hALR-interacting protein by phage-displayed technique and identify its biological activities. METHODS: The specific phage clones that interacted with target protein hALR from a cDNA library of hepatocarcinoma cells were selected using the T7 phage-displayed technique. The acquired cDNA inserts were sequenced and analyzed by bioinformatic tools. The biological activities of the phage-displayed peptide affecting QGY hepatocarcinoma cells were studied using 3H-TdR method. RESULTS: The cDNA inserts with 212 bp were acquired after 4 rounds of biopanning. They showed 100% homology with citron kinase. The phage-displayed peptide and the peptide combined with hALR affected QGY cells proliferation. CONCLUSIONS: hALR-interacting peptide can be specifically screened by phage-displayed technique. Citron kinase that interacted with hALR potentially plays an important role in the proliferation of hepatocarcinoma cells.

Carcinoma, Hepatocellular↗
PubMed2006

[Inhibitory effect of blocking expression of human augmenter of liver regeneration (hALR) on proliferation of hepatocellular carcinoma cell line HepG2].

BACKGROUND & OBJECTIVE: Human augmenter of liver regeneration (hALR) is highly expressed in hepatocellular carcinoma (HCC), but rarely expressed in normal liver cells. ALR could stimulate the proliferation of HCC cell line in vitro, but has no effect on normal hepatocytes. This study was to investigate the inhibitory effect of blocking the expression of hALR on the proliferation of HCC cell line HepG2 using small interfering RNA (siRNA) targeting ALR and anti-ALR monoclonal antibody (McAb). METHODS: RNA interference (RNAi) plasmid pSIALR-A targeting hALR cDNA and control plasmid pSIALR-B were constructed and transfected into HepG2 cells, respectively. After transfection, the expression of green fluorescent protein was observed under a fluorescent microscope to calculate transfection efficiency, the protein level of hALR was measured by immunocytochemistry, meanwhile, the expression of hALR mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). (3)H-TdR incorporation approach was performed to detect the proliferation of HepG2 cells after transfection and after neutralization with anti-hALR McAb. RESULTS: hALR was expressed in HepG2 cells. Plasmids pSIALR-A and pSIALR-B were successfully constructed. Both immunocytochemistry and RT-PCR showed that pSIALR-A inhibited the expression of hALR in HepG2 cells significantly by 83% as compared with pSIALR-B. pSIALR-A specifically inhibited the growth of HepG2 cells after transfection. (3)H-TdR incorporation of pSIALR-A/HepG2 cells was significantly lower than that of pSIALR-B/HepG2 cells (67 687+/-6 548 vs. 104 807+/-5 713, P<0.05). Anti-hALR McAb markedly inhibited the autonomous growth of HepG2 cells (P<0.05). CONCLUSIONS: hALR is highly expressed in HepG2 cells. The short interfering RNA targeting hALR gene could specifically suppress the expression of hALR, and subsequently inhibit the growth of HepG2 cells. Anti-hALR McAb could partially inhibit the autonomous growth of HepG2 cells.

Antibodies, Monoclonal↗
PubMed2006

[Study on the application of chemometrics methods in chemical characteristic fingerprinting of Fritillaria].

A method for determination of eleven samples in Fritillaria by HPLC with UV detection at 215 nm was described. The column was used a XDP-C18, 4.6 x 250 mm, 5 microm, and the mobile phase was methanol-water (volume: volume = 70: 30, to be added 7.5 mmol/L SDS, pH 4.5 +/- 0.1). Important parameters with chromatograms of eleven samples were obtained and crusted. The results indicated that it is similar between clustering analysis and taxonomy of Fritillaria. Identification of Fritillaria and establishment of the chemical characteristic fingerprinting can used the methods.

Alkaloids↗
PubMed2005

Murine implantation serine proteinases 1 and 2: structure, function and evolution.

Implantation is a vital phase in pregnancy whereupon the hatched embryo invades into the uterine wall to establish intimate contacts with the mother for further development. Although it is generally believed that proteinases are major factors that confer the embryo its invasive character, the nature of proteinases involved in implantation remain mostly elusive. In this article, we review the organization, structure and postulated function of the implantation serine proteinase (ISP1 and 2) genes. The ISPs are embedded within a cluster of tryptase genes on mouse chromosome 17. They are most closely related to members of the mast cell tryptase family, indicating that they may possess some properties characteristic of tryptases including multimerization-dependent activation. The significant similarities found in regulatory regions of ISP genes, together with the observation that ISP proteins are co-expressed and heterodimerize in the embryo and uterus suggests that they are intimately co-regulated during implantation. Inhibition of ISP proteolytic function has implicated this enzyme in the processes of embryo hatching and implantation.

Amino Acid Sequence↗