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Liming Wang

Publications and source records attributed to Liming Wang.

At least 19 recordsLinked to original sources
PubMed2025

STING inhibits LINE-1 retrotransposition through sorting ORF1p to lysosomes for degradation.

The cyclic dinucleotide sensor stimulator of interferon (IFN) genes (STING) is known for its critical role in interferon and inflammatory responses. In addition, STING also has functions independent of interferon induction. In this study, we report that STING restricts the mobilization of the cellular retrotransposon long interspersed nuclear element 1 (LINE-1) independent of cGAS and interferon induction. LINE-1 is the only active autonomous retrotransposable element in the human genome and its transposition can cause genetic and autoimmune diseases. STING inhibition of LINE-1 requires its dimerization. Mechanistically, STING interacts with LINE-1 ORF1p, then the complex translocates to the ER-Golgi intermediate compartment (ERGIC) and the Golgi followed by sorting to Rab7-positive lysosomes for degradation. Our data unveil a function of STING in maintaining host genome integrity by restricting LINE-1 retrotransposition via an IFN-independent mechanism.

Humans↗
PubMed2007

Novel triterpenoid 25-hydroxy-3-oxoolean-12-en-28-oic acid induces growth arrest and apoptosis in breast cancer cells.

25-Hydroxy-3-oxoolean-12-en-28-oic acid (Amooranin-AMR) is a triterpene acid isolated from the stem bark of a tropical tree (Amoora rohituka) grown wild in India. A herbal preparation used for the treatment of cancer by the Ayurvedic system of medicine contains the stem bark of Amoora rohituka as one of the ingredients. In this paper, we show that AMR displays a strong inhibitory effect on survival of human breast carcinoma MDA-468, breast adenocarcinoma MCF-7 cells compared to breast epithelial MCF-10A control cells. A 50% decrease in cells (IC50) ranged from 1.8 to 14.6 microM and cell growth was suppressed by arresting cell cycle at G2 + M phase. AMR effectively induces apoptosis and triggered a series of effects associated with apoptosis including cleavage of caspase-8, -9, -3, Bid and ER stress in MDA-468 cells and caspase- 8, -9, -6 and Bid in MCF-7 cells, release of cytochrome c from the mitochondria, cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation with a concomitant upregulation of p53, Bax and down-regulation of Bcl-2 in MDA-468 cells, but Bax unchanged in MCF-7 cells. The use of caspase blocking peptides and acridine orange staining confirmed the involvement of primarily caspase-9 and -3 in MDA-468 cells with mutated p53 and primarily caspase-8, -9 and -6 in MCF-7 cells expressing wt p53. We also observed in MCF-7/p53siRNA cells AMR treatment caused reduced expression of Bcl-2 without affecting levels of Bax similar to MCF-7 cells treated with AMR and proteolytic activation of Bax in MDA-468 cells. These results suggest that AMR induces apoptosis in human breast carcinoma cells via caspase activation pathway and likely it is a p53-independent apoptosis.

Apoptosis↗
PubMed2006

Mammary carcinogenesis in transgenic mice expressing a dominant-negative mutant of DNA polymerase beta in their mammary glands.

DNA polymerase beta (polbeta) is a major contributor to mammalian DNA damage repair through its gap-filling DNA synthesis and 5'-deoxyribose phosphate lyase activities. In this way, polbeta plays pivotal roles in the repair of oxidative DNA damage, replication, embryonic survival, neuronal development, meiosis, apoptosis and telomere function. A 36 kDa truncated polbetaDelta protein is expressed in human colorectal, breast, lung and renal carcinomas, but not in normal matched tissues. Interestingly, a binary protein-protein complex of polbetaDelta and X-ray cross-complementing group 1 acts as dominant-negative mutant. In this study, the potential tumorigenic activity of polbetaDelta was examined in nude and transgenic mouse models. Mouse embryonic fibroblasts (MEFs) expressing polbetaDelta in the absence of endogenous polbeta exhibited increased susceptibility to N-methyl-N-nitrosourea (MNU)-induced morphological transformation as compared with cells expressing wild-type (WT) polbeta. This was accompanied by reduced gap-filling DNA synthesis activity. Anchorage-independent transformed cells derived from polbetaDelta-expressing MEFs induced 100% tumor occurrence in nude mice. To support these data, we established transgenic mice expressing polbetaDelta specifically in the mammary glands from a whey acidic protein promoter-driven transgene. This is the first report of transgenic mice with tissue-specific expression of polbetaDelta. MNU-induced tumor formation was analyzed in transgenic mice expressing polbetaDelta together with endogenous WT polbeta in their mammary glands and in normal control mice expressing only WT polbeta. The latent period of tumor appearance was markedly shorter and tumor incidence was significantly higher in transgenic animals than in control animals treated under the same conditions. These results indicate that cells expressing the mutant polbetaDelta display an enhanced sensitivity to MNU that probably underlies an increased susceptibility to tumorigenesis.

Animals↗
PubMed2006

Determination of the temperature and pressure dependence of the reaction OH + C2H4 from 200-400 K using experimental and master equation analyses.

The pressure and temperature dependence for the reaction of OH + C(2)H(4) was studied over the range of conditions: 200-400 K and 5-600 Torr by laser flash photolysis, laser-induced fluorescence (FP-LIF). Additional experiments were conducted at room temperature by laser flash photolysis, cavity ring-down spectroscopy to facilitate determination of the high pressure limit. One-dimensional master equation calculations were conducted to test the temperature and pressure dependence of the reaction in He and in N(2). The energetics of the reaction and geometries of intermediate species were calculated by ab initio calculations (DFT-BH&HLYP/6-311+G(3df,2p) and CBS-APNO level along DFT-IRC, respectively. An investigation into the importance of a pre-reaction van der Waals complex on the kinetics over the pressure range of the troposphere is discussed. The high pressure rate coefficient was extracted by fitting the master equation calculations to the data and yields k(infinity) = 5.01 x 10(-12) exp(148/T) cm(3) molecule(-1) s(-1). The master equation calculations were then optimized for the pressure fall-off in He and N(2) by varying the average downward energy transfer parameter (DeltaE(down)) for the different collision partners and finally fitted to a Troe expression to determine k(o) and F(cent) for use in atmospheric modeling.

Ethylenes↗
PubMed2006

Kinetics of decolorization of azo dye by bipolar pulsed barrier discharge in a three-phase discharge plasma reactor.

Removal of amaranth, a commercial synthetic azo dye widely used in the dye and food industry, was examined as a possible remediation technology for treating dye-contaminated water. Effects of various parameters such as gas flow rate, solution conductivity, pulse repetition frequency, etc., on decolorization kinetics were investigated. Experimental results show that an aqueous solution of 24 mg/l dye is 81.24% decolorized following 30 min plasma treatment for a 50 kV voltage and 0.75 m(3)/h gas flow rate. Decolorization reaction of amaranth in the plasma reactor is a pseudo first order reaction. Rate constant (k) of decolorization increases quickly with increasing the applied voltage, pulse repetition frequency and the gas flow rate. However, when the applied voltage is beyond 50 kV and increases further, increase rate of k decreases. In addition, k decreases quickly when the solution conductivity increases from 200 to 1481 microS/cm. The decolorization reaction has a high rate constant (k=0.0269 min(-1)) when the solution pH is beyond 10. Rate constant k decreases with the decrease of pH and reaches minimum at a pH of about 5 (k(min)=0.01603 min(-1)), then increases to 0.02105 min(-1) when pH decreases to 3.07. About 15% of the initial TOC can be degraded only in about 120 min non-thermal plasma treatment.

Azo Compounds↗
PubMed2006

Galphaq-dependent signaling cascades stimulate water-seeking behavior.

We used the mouse nephrin promoter to express a constitutively active Galphaq [Galphaq(Q>L)] transgene in mice. As previously reported, the transgene was expressed in kidney, pancreas, and brain, and the kidney phenotype was characterized by albuminuria and reduced nephron mass. Additional studies revealed a second phenotype characterized by polyuria and polydipsia. The polyuric phenotype was not caused by abnormal glucose metabolism or hypercalcemia but was accompanied by reduced urinary concentrating ability. Additional studies found that 1) water restriction was associated with an appropriate increase in serum vasopressin levels in transgenic (TG) mice; 2) the urinary concentrating defect was not corrected by administration of desamino-d-arginine vasopressin (DDAVP); and 3) papillary length was similar in TG and non-TG mice. To examine the renal response to DDAVP at the molecular level, we monitored aquaporin 2 (AQP2) and vasopressin V2 receptor (V2R) mRNA levels in mouse kidney. Consistent with the known effects of vasopressin, administration of DDAVP caused a decrease in V2R mRNA levels and an increase in AQP2 mRNA levels in both TG and non-TG animals, suggesting an appropriate renal response to DDAVP in the TG mice. To determine whether the urine concentrating abnormality was the result of primary polydipsia, water intake by TG mice was restricted to the amount ingested by non-TG animals. After 5 days, urinary concentrating ability was similar in TG mice and non-TG littermate controls. These data are consistent with the notion that expression of the Galphaq(Q>L) transgene in the brain induced primary polydipsia in the TG mice.

Animal Feed↗
PubMed2006

Neutrotolerant acidophilic Streptomyces species isolated from acidic soils in China: Streptomyces guanduensis sp. nov., Streptomyces paucisporeus sp. nov., Streptomyces rubidus sp. nov. and Streptomyces yanglinensis sp. nov.

The taxonomic status of six neutrotolerant acidophilic streptomycetes isolated from acidic soils in Yunnan Province, China, was established using a polyphasic approach. The morphological and chemotaxonomic characteristics revealed that the isolates belong to the genus Streptomyces. Almost complete 16S rRNA gene sequences of the isolates were determined and aligned with available corresponding sequences of representatives of the family Streptomycetaceae; phylogenetic trees were inferred using four tree-making algorithms. The isolates formed a distinct, albeit heterogeneous, subclade in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces yeochonensis, but were readily distinguishable from the latter using DNA-DNA hybridization and phenotypic data. It was evident from the genotypic and phenotypic data that the isolates belonged to four novel Streptomyces species, for which the following names are proposed: Streptomyces guanduensis sp. nov. (type strain 701T=CGMCC 4.2022T=JCM 13274T), Streptomyces paucisporeus sp. nov. (type strain 1413T=CGMCC 4.2025T=JCM 13276T), Streptomyces rubidus sp. nov. (type strain 13c15T=CGMCC 4.2026T=JCM 13277T) and Streptomyces yanglinensis sp. nov. (type strain 1307T=CGMCC 4.2023T=JCM 13275T); isolates 317 and 913 belong to this latter species.

Bacterial Typing Techniques↗
PubMed2006

Streptacidiphilus oryzae sp. nov., an actinomycete isolated from rice-field soil in Thailand.

The taxonomic position of ten acidophilic actinomycetes isolated from an acidic rice-field soil was established using a polyphasic approach. 16S rRNA gene sequences determined for the isolates were aligned with corresponding sequences of representatives of the genera Kitasatospora, Streptacidiphilus and Streptomyces and phylogenetic trees were inferred using four tree-making algorithms. The isolates had identical sequences and formed a distinct branch at the periphery of the Streptacidiphilus 16S rRNA gene tree. The chemotaxonomic and morphological properties of representative isolates were consistent with their assignment to the genus Streptacidiphilus. The isolates shared nearly identical phenotypic profiles that readily distinguished them from representatives of the established species of Streptacidiphilus. It is evident from the genotypic and phenotypic data that the isolates form a homogeneous group that corresponds to a novel species in the genus Streptacidiphilus. The name proposed for this new taxon is Streptacidiphilus oryzae sp. nov.; the type strain is strain TH49(T) (=CGMCC 4.2012(T) = JCM 13271(T)).

Actinobacteria↗
PubMed2006

[Effects of periosteum, synovium and cartilage tissues on genes for joint cartilage regeneration].

OBJECTIVE: To study the effects of the periosteum,synovium and cartilage tissues on the gene expressions of proteoglycan, collagen II, and nuclear factor kappa B (NF-kappaB) and to investigate the different effects of these tissues on cartilage regeneration. METHODS: In 20 New Zealand white rabbits, 20 cartilage explants were taken from the knee joints in each rabbit, the size of which was 4 mm x 4 mm x 4 mm. All the cartilages were divided into the following 4 groups and cultured for 7 days: Group A, with 5 pieces (2 mm x 2 mm) of the synovium of the knee joints in each dish; Group B, with 5 pieces (2 mm x 2 mm) of the periosteum in each dish; Group C, with 5 pieces (2 mm x 2 mm x 2 mm) of the cartilage in each dish; and Group D, with no addition of other tissues (control group). RNA was extracted from the cells of the cartilage explants (4 mm x 4 mm x 4 mm) in all the dishes. The gene expressions of proteoglycan, collagen II and NF-kappaB were defected by a reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In group A, the gene expression of proteoglycan was significantly decreased. The relative density of this gene expression had a significant difference when compared with that in group D (1.09 +/- 0.21 vs. 1.25 +/- 0.25, P < 0.05); the gene expressions of collagen I and NF-kappaB were also decreased, but they had no significant differences when compared with those in group D (P > 0.05). In group B, the gene expressions of proteoglycan, collagen II, and NF-kappaB were significantly increased. The relative densities of these gene expressions were 1.60 +/- 0.26, 1.57 +/- 0.24, and 4.20 +/- 2.22, respectively, which had significant differences when compared with those in group D (P < 0.05). In group C, the relative density of the gene expression of collagen II was 1.43 +/- 0.28, which had a significant difference when compared with that in group D (P < 0.05), but the relative densities of the gene expressions of proteoglycan and NF-kappaB had no significant differences when compared with those in group D (P > 0.05). CONCLUSION: The results indicate that the periosteum can up-regulate the gene expressions of proteoglycan, collagen II and NF-kappaB. The NF-kappaB is likely to be an important nuclear transcription factor related to cartilage regeneration. The results also suggest that the periosteum may be better in facilitating the cartilage repair and regeneration in clinical practice.

Animals↗
PubMed2005

Activation of Galpha q-coupled signaling pathways in glomerular podocytes promotes renal injury.

The glomerular podocyte plays a key role in maintaining the integrity of the glomerular filtration barrier. This function may be regulated by activation of cell surface G protein-coupled receptors (GPCR). Studies suggest that podocytes express GPCR that are implicated in the pathogenesis of glomerular diseases. Common to these GPCR systems is activation of phospholipase C through the Gq alpha-subunit (Galpha q). For investigating the role of Galpha q-coupled signaling pathways in promoting renal injury in podocytes, a constitutively active Galpha q subunit (Galpha qQ > L) was expressed in glomerular podocytes using the mouse nephrin promoter. Transgenic (TG) mice demonstrated albuminuria as well as a decrease in both kidney mass and nephron number. By light microscopy, a portion of the TG mice had glomerular abnormalities, including focal to diffuse hypercellularity and segmental sclerosis. Consistent with injury-promoting effects of Galpha qQ > L, there was a significant reduction in podocalyxin mRNA as well as nephrin mRNA and protein levels in glomeruli from TG mice compared with non-TG controls. Expression of the transgene also seemed to increase susceptibility to glomerular injury, because treatment with puromycin aminonucleoside enhanced proteinuria in TG mice compared with non-TG littermate controls (4.2 +/- 1.0 [TG] versus 1.6 +/- 0.3 [non-TG] mg/24 h; P = 0.0161). Thus, activation of Galpha q in glomerular podocytes caused alterations in glomerular histomorphology, albuminuria, decreased nephron mass, and reduced glomerular expression of both nephrin and podocalyxin as well as enhanced susceptibility to glomerular damage induced by puromycin aminonucleoside. It is speculated that Galpha q-coupled signaling cascades may be important effector pathways mediating renal injury.

Albuminuria↗
PubMed2005

The human tumor antigen PRAME is a dominant repressor of retinoic acid receptor signaling.

Retinoic acid (RA) induces proliferation arrest, differentiation, and apoptosis, and defects in retinoic acid receptor (RAR) signaling have been implicated in cancer. The human tumor antigen PRAME is overexpressed in a variety of cancers, but its function has remained unclear. We identify here PRAME as a dominant repressor of RAR signaling. PRAME binds to RAR in the presence of RA, preventing ligand-induced receptor activation and target gene transcription through recruitment of Polycomb proteins. PRAME is present at RAR target promoters and inhibits RA-induced differentiation, growth arrest, and apoptosis. Conversely, knockdown of PRAME expression by RNA interference in RA-resistant human melanoma restores RAR signaling and reinstates sensitivity to the antiproliferative effects of RA in vitro and in vivo. Our data suggest that overexpression of PRAME frequently observed in human cancers confers growth or survival advantages by antagonizing RAR signaling.

Animals↗
PubMed2005

Mechanistic studies of the pyrolysis of 1,3-butadiene, 1,3-butadiene-1,1,4,4-d4, 1,2-butadiene, and 2-butyne by supersonic jet/photoionization mass spectrometry.

The thermal decomposition of 1,3-butadiene, 1,3-butadiene-1,1,4,4-d(4), 1,2-butadiene, and 2-butyne at temperatures up to 1520 K was carried out by flash pyrolysis on a approximately 20 mus time scale. The reaction products were isolated by supersonic expansion and detected by single-photon (lambda = 118 nm) vacuum-ultraviolet time-of-flight mass spectrometry (VUV-TOFMS). Direct detection of CH(3) and C(3)H(3), as well as C(3)H(4), C(4)H(4), and C(4)H(5) products, provides insight into the initial steps involved in the complex pyrolysis of these C(4)H(6) species below T = 1500 K. The similar pyrolysis product distributions for the C(4)H(6) isomers on such a short time scale support the previously proposed mechanism of facile isomerization of these species. Isomerization of 1,3-butadiene to 1,2-butadiene and subsequent C-C bond fission of 1,2-butadiene to produce CH(3) and C(3)H(3) (propargyl) are most likely the primary initial radical production channel in the 1,3-butadiene pyrolysis.

Journal Article↗
PubMed2005

Photolysis of methylethyl, diethyl and methylvinyl ketones and their role in the atmospheric HOx budget.

Quantum yields for acyl (RCO) radical production from ketone photolysis as a function of temperature, pressure and the atmospherically relevant wavelengths (308 and 320 nm) have been determined for methylethyl ketone (MEK), methylvinyl ketone (MVK) and diethyl ketone (DEK) via direct observation of the OH product from the RCO + O2 reaction. The methodology has been applied previously to acetone photolysis. The kinetics and OH yields of the RCO + O2 reactions have been investigated to demonstrate that this technique can be used to monitor the dissociation of higher ketones. These kinetic studies have been used to confirm CH3CO + R as the dominant radical dissociation mechanism in the unsymmetrical ketones MVK and MEK. At 308 nm MEK and DEK photolysis follows conventional Stern Volmer behaviour. MEK and DEK are quenched less efficiently than acetone; quenching efficiency increases with decreasing temperature (213-295 K). At 320 nm Stern Volmer plots of the RCO quantum yields show evidence for the involvement of multiple states in the dissociation. The wavelength dependence of this phenomenon is compared with that for acetone and the atmospheric implications for MEK and DEK lifetimes have been investigated by converting the measured quantum yields to photolysis rates. The calculated rates under typical atmospheric conditions are a factor 2-3 lower than if the quantum yields in the literature are used, influencing both the overall atmospheric lifetime of these ketones and their relative rates of removal by reaction with OH and by photolysis.

Journal Article↗
PubMed2005

Kitasatospora viridis sp. nov., a novel actinomycete from soil.

The taxonomic position of a rhizosphere isolate, strain 52108a(T), was determined using a polyphasic approach. The strain was found to have chemical and morphological properties consistent with its assignment to the genus Kitasatospora. An almost complete 16S rRNA gene sequence determined for the strain was aligned with corresponding sequences of representatives of the genus Kitasatospora and related taxa using three tree-making algorithms. The organism formed a distinct phyletic line within the Kitasatospora clade and was most closely related to Kitasatospora arboriphila (98.9 %), Kitasatospora kifunensis (99.0 %), Kitasatospora paracochleata (98.4 %) and Kitasatospora terrestris (98.2 %), but was readily distinguished from representatives of these species using a combination of phenotypic properties. The combined genotypic and phenotypic data show that the strain should be classified in the genus Kitasatospora as a novel species. The name proposed is Kitasatospora viridis sp. nov., with the type strain 52108a(T) (=AS 4.1878(T)=DSM 44826(T)).

Camellia↗
PubMed2005

Streptomyces jietaisiensis sp. nov., isolated from soil in northern China.

An actinomycete, strain FXJ46(T), was isolated from cypress forest soil in northern China and shown to have chemotaxonomic and morphological properties consistent with streptomycetes. It developed greyish aerial mycelium and pinkish-brown substrate mycelium on oatmeal agar. Phylogenetic analyses based on an almost complete 16S rRNA gene sequence of the strain and on the 120 nucleotide variable gamma-region of this molecule showed that it formed a distinct (but closely associated) line with Streptomyces griseoaurantiacus DSM 40430(T) in Streptomyces trees. However, the DNA-DNA relatedness between the two strains was only 48.8%. A number of phenotypic properties also readily distinguished the isolate from S. griseoaurantiacus and related Streptomyces species with validly published names. It is proposed, therefore, that this organism be classified as a novel species of the genus Streptomyces, for which the name Streptomyces jietaisiensis sp. nov. is proposed. The type strain is FXJ46(T) (=AS 4.1859(T)=JCM 12279(T)).

Bacterial Typing Techniques↗
PubMed2005

Nocardia jiangxiensis sp. nov. and Nocardia miyunensis sp. nov., isolated from acidic soils.

The taxonomic positions of two soil actinomycetes, strains 117(T) and 43401(T), provisionally assigned to the genus Nocardia were determined in a polyphasic study. The organisms were found to have phenotypic properties typical of members of the genus Nocardia, and formed a distinct branch in the Nocardia 16S rRNA gene tree. It was evident from the phylogenetic data that the isolates were most closely, albeit loosely, associated with the type strains of Nocardia nova and Nocardia pseudobrasiliensis. However, all four of these organisms were readily distinguishable from one another using DNA-DNA relatedness and phenotypic data. It is evident from the genotypic and phenotypic data that the two isolates should be recognized as novel species of the genus Nocardia. It is proposed, therefore, that strains 117(T) (=CGMCC 4.1904(T)=JCM 12860(T)) and 43401(T) (=CGMCC 4.1905(T)=JCM 12861(T)) be classified in the genus Nocardia as the type strains of Nocardia miyunensis sp. nov. and Nocardia jiangxiensis sp. nov., respectively.

Bacterial Typing Techniques↗
PubMed2005

Arthrobacter scleromae sp. nov. isolated from human clinical specimens.

A gram-positive, coryneform bacterium was isolated from swollen scleromata of a dermatosis patient. An analysis of its phenotypic, chemotaxonomic, and genotypic characteristics showed that this bacterium is closely associated with Arthrobacter oxydans and Arthrobacter polychromogenes but that it belongs to a distinct species, for which the name Arthrobacter scleromae sp. nov. is proposed.

Adult↗