共查询到20条相似文献,搜索用时 31 毫秒
1.
Here we show that low-dose cyclophosphamide (CY), that depends for its therapeutic effectiveness on the immunopotentiating
activity of the drug for T cell-mediated tumor-eradicating immunity, is curative for ~80% of wild-type (WT) mice bearing a
large s.c. MOPC-315 tumor, but only for ~10% of IFN-α/βR−/− mice bearing a large s.c. MOPC-315 tumor. Histopathological examination of the s.c. tumors of such mice on day 4 after the
chemotherapy revealed that the low dose of CY led to accumulation of T lymphocytes in both the WT and the IFN-α/βR−/− mice. However, in the CY treated tumor bearing WT mice the T lymphocytes were present throughout the tumor mass and in direct
contact with tumor cells, but in the CY treated tumor bearing IFN-α/βR−/− mice most of the T lymphocytes remained in blood vessels. In addition to being important for CY-induced transendothelial
migration of T lymphocytes into the tumor mass, we show here that signaling via the IFN-α/βR is also important for CY-induced
control of metastatic tumor progression in the spleen and liver of the tumor bearing mice. Finally, CY cured tumor bearing
WT mice were resistant to a subsequent challenge with MOPC-315 tumor cells, but the few CY cured tumor bearing IFN-α/βR−/− mice were not. Thus, signaling via the IFN-α/βR on host cells in MOPC-315 tumor bearers is important for CY-induced: (a)
transendothelial migration of T lymphocytes into the tumor mass and the eradication of the primary tumor, (b) control of metastatic
tumor progression, and (c) resistance to a subsequent tumor challenge.
This work was supported by Research Grant 03-19 from the American Cancer Society-Illinois Division. 相似文献
2.
To achieve higher level expression of Interferon α2b (IFN-α2b) in methylotrophic yeast (Pichia pastoris), a cDNA fragment coding for the mature IFN-α2b was designed and synthesized based on the synonymous codon bias of P. pastoris and optimized G+C content. The synthetic IFN-α2b was inserted into the secreted expression vector pPICZαA, and then integrated
into P. pastoris GS115 genome by electroporation. Multi-copy integrants in the Mut+ recombinant P. pastoris strain were screened by high concentrations of Zeocin. 120 hours culturing allowed expression of the IFN-α2b transformant
up to 810 mg/L as detected by SDS-PAGE and quantitative methods. In addition, Western blot analysis showed that the recombinant
proteins had immunogenicity. The significant antiviral activity of the recombinant IFN-α2b protein was verified by WISH/ VSV
system, which was 3.3×105 IU/mL.
Foundation items: The National ‘973’ Basic Research Program (2002CB111302); The National Natural Science Foundation of China
(30370807) 相似文献
3.
Wujiang Liu Michael A. O’Donnell Xiaohong Chen Ruifa Han Yi Luo 《Cancer immunology, immunotherapy : CII》2009,58(10):1647-1655
Purpose The proper induction of cellular immunity is required for effective bacillus Calmette-Guérin (BCG) immunotherapy of bladder
cancer. It has been known that BCG stimulation of human peripheral blood mononuclear cells (PBMC) leads to the generation
of effector cells cytotoxic to bladder cancer cells in vitro. To improve BCG therapy, we previously developed human interferon
(IFN)-α 2B secreting recombinant (r) BCG (rBCG-IFN-α). We demonstrated that rBCG-IFN-α augmented T helper type 1 (Th1) cytokine
IFN-γ production by PBMC. In this study, we further investigated whether rBCG-IFN-α could also enhance PBMC cytotoxicity toward
bladder cancer cells.
Materials and methods PBMC were prepared from healthy individuals, left alone or stimulated with rBCG-IFN-α or control MV261 BCG, and used as effector
cells in 51Cr-release assays. Human bladder cancer cell lines T24, J82, 5637, TCCSUP, and UMUC-3 were used as target cells. To determine
the role of secreted rIFN-α as well as endogenously expressed IFN-γ and IL-2 in inducing the cytotoxicity, PBMC were stimulated
with rBCG-IFN-α in the presence of neutralizing antibodies to IFN-α, IFN-γ or IL-2. To determine the role of natural killer
(NK) and CD8+ T cells in inducing the cytotoxicity, both cell types were isolated after BCG stimulation of PBMC and used as effector cells
in 51Cr-release assays.
Results Non-stimulated PBMC showed basal levels of cytotoxicity against all target cell lines tested. MV261 BCG increased the PBMC
cytotoxicity by 1.8- to 4.2-fold. rBCG-IFN-α further increased the PBMC cytotoxicity by up to 2-fold. Elevated production
of IFN-γ and IL-2 by PBMC was observed after rBCG-IFN-α stimulation. Blockage of IFN-α, IFN-γ or IL-2 by neutralizing antibodies
during rBCG-IFN-α stimulation reduced or abolished the induction of PBMC cytotoxicity. Both NK and CD8+ T cells were found to be responsible for the enhanced PBMC cytotoxicity induced by rBCG-IFN-α with the former cell type being
more predominant.
Conclusions rBCG-IFN-α is an improved BCG agent that induces enhanced PBMC cytotoxicity against bladder cancer cells in vitro. This rBCG
strain may serve as an alternative to BCG for the treatment of superficial bladder cancer. 相似文献
4.
Many working environments are predisposed for larger than average amounts of fungi and other microorganisms often due to organic
material being handled. From 2003 to 2007, the area used for strawberry production in Denmark increased by 62%. The purpose
of this study was to determine the levels of exposure to microorganisms, endotoxin, (1→3)-β-d-glucan (β-glucan), and pollen in a field of strawberries. The study was carried out in eastern Denmark from the middle of
June to the beginning of August 2008. The strawberries were grown organically, and microbiological pest control agents (MPCAs)
were applied during this and former growth seasons. In order to measure exposure to inhalable bioaerosol components, we used
stationary filter samplers. Bioaerosol sampling was performed during 4 working days, and a total of 57 samplings were performed.
The filters were analysed for contents of fungi, MPCAs, endotoxin, β-glucan, and pollen. The mean exposure was 6,154 CFU Cladosporium sp. m−3, 1.0 × 105 fungal spores m−3, 4.1 × 104 hyphal fragments m−3, 5.8 × 103 pollen m−3, 57.3 ng β-glucan m−3, and 8.9 endotoxin units (EU) m−3. A significant and positive correlation was found between β-glucan and fungal spores and between CFU of Cladosporium sp. and CFU of fungi. We selected specifically for Metarhizium anisopliae, Beauveria bassiana, and the applied MPCAs Trichoderma harzianum, T. polysporum, and Bacillus thuringiensis but found none of these species. In conclusion, our study shows that berry pickers in this organic strawberry field were
potentially subjected to higher levels of fungal spores, Cladosporium sp., hyphal fragments, pollen, and thus also β-glucan than is usually seen in outdoor air. Exposure to MPCAs was not seen.
The exposure to endotoxin was only slightly higher than e.g. in a town. 相似文献
5.
Katarzyna Grzelkowska-Kowalczyk Wioletta Wieteska-Skrzeczyńska 《Cellular & molecular biology letters》2010,15(1):13-31
The aim of this study was to compare the effects of TNF-α, IL-1β and IFN-γ on the activation of protein kinase B (PKB), p70S6k, mitogen-activated protein kinase (MAPK) and p90
rsk
, and on IGF-I-stimulated glucose uptake and protein synthesis in mouse C2C12 myotubes. 100 nmol/l IGF-I stimulated glucose
uptake in C2C12 myotubes by 198.1% and 10 ng/ml TNF-α abolished this effect. Glucose uptake in cells differentiated in the
presence of 10 ng/ml IFN-γ increased by 167.2% but did not undergo significant further modification upon the addition of IGF-I.
IGF-I increased the rate of protein synthesis by 249.8%. Neither TNF-α nor IFN-γ influenced basal protein synthesis, but both
cytokines prevented the IGF-I effect. 10 ng/ml IL-1β did not modify either the basal or IGF-I-dependent glucose uptake and
protein synthesis. With the exception of TNF-α causing an 18% decrease in the level of PKB protein, the cellular levels of
PKB, p70S6k, p42MAPK, p44MAPK and p90
rsk
were not affected by the cytokines. IGF-I caused the phosphorylation of PKB (an approximate 8-fold increase above the basal
value after 40 min of IGF-I treatment), p42MAPK (a 2.81-fold increase after 50 min), and the activation of p70S6k and p90
rsk
, manifesting as gel mobility retardation. In cells differentiated in the presence of TNF-α or IFN-γ, this IGF-I-mediated
PKB and p70S6k phosphorylation was significantly diminished, and the increase in p42MAPK and p90
rsk
phosphorylation was prevented. The basal p42MAPK phosphorylation in C2C12 cells treated with IFN-γ was high and comparable with the activation of this kinase by IGF-I. Pretreatment
of myogenic cells with IL-1β did not modify the IGF-I-stimulated phosphorylation of PKB, p70S6k, p42MAPK and p90
rsk
. In conclusion: i) TNF-α and IFN-γ, but not IL-1β, if present in the extracellular environment during C2C12 myoblast differentiation,
prevent the stimulatory action of IGF-I on protein synthesis. ii) TNF-α- and IFN-γ-induced IGF-I resistance of protein synthesis
could be associated with the decreased phosphorylation of PKB and p70S6k. iii) The activation of glucose uptake in C2C12 myogenic cells treated with IFN-γ is PKB independent. iv) The similar effects
of TNF-α and IFN-γ on the signalling and action of IGF-I on protein synthesis in myogenic cells could suggest the involvement
of both of these cytokines in protein loss in skeletal muscle. 相似文献
6.
Formation of single- and double-strand breaks of pBR322 plasmid irradiated in the presence of scavengers 总被引:1,自引:0,他引:1
By the method of gel electrophoresis, radiation-induced DNA single- and double-strand breaks (SSB, DSB) were studied with
a model system of pBR322 solution in vitro in the presence of ·OH radical scavengers, mannitol and TE (10–2 mol dm–3 Tris and 10–3 mol dm–3 ethylene diamine tetra-acetic acid). Experiments showed that SSB resulted from one-hit events of radiation energy deposition
and DSB resulted from both one-hit and two-hit energy deposition events and so were distinguished into two classes of αDSB
and βDSB. Moreover, α/β, where α is the number of DSB per unit dose induced in one irradiation event and β the number of DSB
per unit squared dose induced by the combination of two independent SSB, was related to the scavenging capacity, σ, and for
σ>108 s–1,αDSB predominate over DSB. On the other hand, if σ<2×108 s–1, the measured G(αDSB) decreased in parallel with G(SSB), i.e., G(αDSB)/G(SSB) was a constant. When σ>2×108 s–1, G(αDSB) decreased slightly so that the ratio of αDSB to SSB evidently increased. Therefore, αDSB could be induced by the
radical transfer mechanism for σ<2×108 s–1 and contrarily produced by the local multiply damaged sites (LMDS) mechanism for σ larger than this value. In addition, the
distance for two independent complementary SSB forming a DSB was deduced, but no apparent variation of it was found in the
wide σ range from ∼105 to ∼109 s–1, which shows that the DNA steric structure was not influenced by mannitol.
Received: 28 September 1998 / Accepted in revised form: 20 March 1999 相似文献
7.
The kinetics of phase separation and microstructure of oat β-glucan/whey protein binary mixtures varying in concentration (4–16% w/v protein, 0.3–1.2% w/v β-glucan) and β-glucan molecular weight (1.3 × 106, 640 × 103, 180 × 103, and 120 × 103 g/mol) was investigated by turbidimetry and fluorescent microscopy. The phase separation of the mixed systems was followed
at pH 7.0 and at room temperature under quiescent conditions. Application of first principles revealed that phase separation
of the systems follows first-order kinetics. Acceleration of the phase-separation process was observed with increase of β-glucan concentration for the three lowest-MW samples but the highest molecular weight (1.3 × 106 g/mol) exhibited the opposite trend. Changes in the polysaccharide molecular weight resulted in considerable differences
in β-glucan aggregate morphology in the mixed systems. The change in the continuity of the mixed system from polysaccharide-,
to bi-, to protein-continuous was confirmed for a wide range of mixed systems differing in biopolymer concentration, and β-glucan molecular weight. 相似文献
8.
Mundy-Bosse BL Young GS Bauer T Binkley E Bloomston M Bill MA Bekaii-Saab T Carson WE Lesinski GB 《Cancer immunology, immunotherapy : CII》2011,60(9):1269-1279
Interferon-alpha (IFN-α) promotes anti-tumor immunity through its actions on immune cells. We hypothesized that elevated percentages
of myeloid-derived suppressor cells (MDSC) and increased pro-inflammatory cytokines in peripheral blood would be associated
with impaired response to IFN-α in patients with gastrointestinal (GI) malignancies. This study evaluated relationships between
plasma IL-6, IL-10, circulating MDSC subsets, and IFN-α-induced signal transduction in 40 patients with GI malignancies. Plasma
IL-6 and IL-10 were significantly higher in patients versus normal donors. CD33+HLADR−CD11b+CD15+ and CD33+HLADR−/lowCD14+ MDSC subsets were also elevated in patients versus normal donors (P < 0.0001). Plasma IL-6 was correlated with CD33+HLADR−CD15+ MDSC (P = 0.008) and IL-10 with CD33+HLADR−CD15− MDSC (P = 0.002). The percentage of CD15+ and CD15− but not CD14+ MDSC subsets were inversely correlated with IFN-α-induced STAT1 phosphorylation in CD4+ T cells, while co-culture with in vitro generated MDSC led to reduced IFN-α responsiveness in both PBMC and the CD4+ subset of T cells from normal donors. Exploratory multivariable Cox proportional hazards models revealed that an increased
percentage of the CD33+HLADR−CD15− MDSC subset was associated with reduced overall survival (P = 0.049), while an increased percentage of the CD33+HLADR−/lowCD14+ subset was associated with greater overall survival (P = 0.033). These data provide evidence for a unique relationship between specific cytokines, MDSC subsets, and IFN-α responsiveness
in patients with GI malignancies. 相似文献
9.
Bert De Klerck Isabelle Carpentier Rik J Lories Yvette Habraken Jacques Piette Geert Carmeliet Rudi Beyaert Alfons Billiau Patrick Matthys 《Arthritis research & therapy》2004,6(3):R220
Collagen-induced arthritis (CIA) in mice is accompanied by splenomegaly due to the selective expansion of immature CD11b+ myeloblasts. Both disease manifestations are more pronounced in interferon-γ receptor knock-out (IFN-γR KO) mice. We have
taken advantage of this difference to test the hypothesis that the expanding CD11b+ splenic cell population constitutes a source from which osteoclast precursors are recruited to the joint synovia. We found
larger numbers of osteoclasts and more severe bone destruction in joints of IFN-γR KO mice than in joints of wild-type mice.
Osteoclast-like multinucleated cells appeared in splenocyte cultures established in the presence of macrophage colony-stimulating
factor (M-CSF) and stimulated with the osteoclast-differentiating factor receptor activator of NF-κB ligand (RANKL) or with
tumour necrosis factor-α (TNF-α). Significantly larger numbers of such cells could be generated from splenocytes of IFN-γR
KO mice than from those of wild-type mice. This was not accompanied, as might have been expected, by increased concentrations
of the intracellular adaptor protein TRAF6, known to be involved in signalling of RANKL- and TNF-α-induced osteoclast formation.
Splenocyte cultures of IFN-γR KO mice also produced more TNF-α and more RANKL than those of wild-type mice. Finally, splenocytes
isolated from immunised IFN-γR KO mice contained comparatively low levels of pro-interleukin-1β (pro-IL-1β) and pro-caspase-1,
indicating more extensive conversion of pro-IL-1β into secreted active IL-1β. These observations provide evidence that all
conditions are fulfilled for the expanding CD11b+ splenocytes to act as a source of osteoclasts and to be indirectly responsible for bone destruction in CIA. They also provide
a plausible explanation for the higher susceptibility of IFN-γR KO mice to CIA. 相似文献
10.
Miki Watanabe Sulaiman Sheriff Theresa A. Ramelot Nijiati Kadeer Junho Cho Kenneth B. Lewis Ambikaipakan Balasubramaniam Michael A. Kennedy 《International journal of peptide research and therapeutics》2011,17(4):281-299
After severe burn injury, proinflammatory cytokine levels are elevated in serum and skeletal muscle, which in turn increases
protein breakdown and decreases protein synthesis. In this study, C2C12 mouse skeletal muscle cell line myotubes were exposed
to proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) as an in vitro cell-line model of catabolic
response to burn injury and then treated with des-acyl ghrelin (DAG), a 28 amino acid polypeptide hormone thought to inhibit
protein breakdown and increase protein synthesis, to assess its therapeutic potential. Nuclear magnetic resonance-based metabonomics
was used to monitor metabolic activity of C2C12 myotubes under four treatment conditions: (1) control, (2) TNF-α/IFN-γ (TI),
(3) DAG (DA), and (4) TNF-α/IFN-γ followed by DAG (TIDA) to assess the effect of DAG treatment on cellular metabolic response
during basal or catabolic conditions. Twelve metabolites showed significant changes in concentrations following treatments
in the hydrophilic cell extracts. Lactate (P < 10−4) and citrulline (P < 10−9) increased with TNF-α/IFN-γ treatment, indicating increased protein degradation, and returned to control levels in the TIDA
group. Adenosine nucleotide levels had decreased trends in TI myotubes that returned to baseline levels after DAG treatment
(P < 10−4). Guanidinoacetate and pantothenate, metabolites involved in protein synthesis and cell proliferation, had increased concentration
trends following DAG treatment in both the DA and TIDA groups. Our metabonomics analysis provides further evidence that DAG
counteracts the catabolic response caused by elevated muscle TNF-α/IFN-γ cytokine levels following severe burns and can play
a potential therapeutic role in treatment of burn injury. 相似文献
11.
Hirokawa Y Fujiwara S Suzuki M Akiyama T Sakamoto M Kobayashi S Tsuzuki M 《Planta》2008,227(3):589-599
The storage β-polyglucan and catabolic enzyme activities of the haptophyte Pleurochrysis haptonemofera were characterized. The storage β-polyglucan was prepared by the dimethylsulfoxide-extraction method. 13C- and 1H-NMR spectroscopy revealed that the polyglucan consists of β-(1→3)- and β-(1→6)-linked glucose polymers, with a β-(1→6)-
to β-(1→3)-linkage ratio of 1.5. Gel permeation chromatography showed that the molecular weight of the polyglucan is 1.1–8.4 × 104 Da, with a peak at 3.4 × 104 Da. The degree of polymerization, which was estimated from the amounts of total carbohydrate and reduced ends, was 203, corresponding
to 3.3 × 104 Da. A method for measurement of the β-polyglucan in a small amount of liquid culture involving a mixture of β-glucanases,
Westase, was established. The β-polyglucan was localized in the soluble fraction of cells. The amount of β-polyglucan per
cell increased at the stationary phase under continuous illumination and decreased in the dark, like those of storage α-polyglucans,
starch of green algae and glycogen of cyanobacteria. The activities of β-1,3- and β-1,6-glucanases involved in the degradation
of the storage β-polyglucan were assayed in vitro, both being optimal at pH 5.0. The β-1,3-glucanase activity, which was detected
on active staining after native polyacrylamide gel electrophoresis, was partially purified by ammonium sulfate precipitation
and anion exchange chromatography. 相似文献
12.
Guenterberg KD Lesinski GB Mundy-Bosse BL Karpa VI Jaime-Ramirez AC Wei L Carson WE 《Cancer immunology, immunotherapy : CII》2011,60(9):1281-1288
Interferon-alpha (IFN-α) is an immunomodulatory cytokine that is used clinically for the treatment of melanoma in the adjuvant
setting. The cellular actions of IFN-α are regulated by the suppressors of cytokine signaling (SOCS) family of proteins. We
hypothesized that the anti-tumor activity of exogenous IFN-α would be enhanced in SOCS1-deficient mice. SOCS1-deficient (SOCS1−/−) or control (SOCS1+/+) mice on an IFN-γ−/− C57BL/6 background bearing intraperitoneal (i.p.) JB/MS murine melanoma cells were treated for 30 days with i.p. injections
of IFN-A/D or PBS (vehicle). Log-rank Kaplan-Meier survival curves were used to evaluate survival. Tumor-bearing control SOCS1+/+ mice receiving IFN-A/D had significantly enhanced survival versus PBS–treated mice (P = 0.0048). The anti-tumor effects of IFN-A/D therapy were significantly enhanced in tumor-bearing SOCS1−/− mice; 75% of these mice survived tumor challenge, whereas PBS-treated SOCS1−/− mice all died at 13-16 days (P = 0.00038). Antibody (Ab) depletion of CD8+ T cells abrogated the anti-tumor effects of IFN-A/D in SOCS1−/− mice as compared with mice receiving a control antibody (P = 0.0021). CD4+ T-cell depletion from SOCS1−/− mice also inhibited the effects of IFN-A/D (P = 0.0003). IFN-A/D did not alter expression of CD80 or CD86 on splenocytes of SOCS1+/+ or SOCS1−/− mice, or the proportion of T regulatory cells or myeloid-derived suppressor cells in SOCS1+/+ or SOCS1−/− mice. An analysis of T-cell function did reveal increased proliferation of SOCS1-deficient splenocytes at baseline and in
response to mitogenic stimuli. These data suggest that modulation of SOCS1 function in T-cell subsets could enhance the anti-tumor
effects of IFN-α in the setting of melanoma. 相似文献
13.
Yanfeng Tuo Lanwei Zhang Xue Han Ming Du Yingchun Zhang Huaxi Yi Weiqin Zhang Yuehua Jiao 《World journal of microbiology & biotechnology》2011,27(3):505-511
The objective of this study was to evaluate the in vitro immunomodulating capacity of Lactobacillus
coryniformis subsp torquens T3L (L.
coryniformis T3L) isolated from traditional fermented yak’s milk in Tibet, China, and Lactobacillus paracasei supsp. paracasei M5L (L. paracasei M5L)isolated from kumiss in Sinkiang, China was used as control. The effects of live bacteria, cell wall and genomic DNA
of the two Lactobacillus strains on human peripheral blood mononuclear cells (PBMCs) proliferation, production of interleukin-12 (IL-12 p70), interferon
gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), and natural killer (NK) cell activity were assessed. The live bacteria,
cell wall and genomic DNA of the two lactobacilli exerted proliferative effects on PBMCs. Live bacteria at 1 × 106 c.f.u. ml−1, cell wall at 20 μg protein ml−1 and DNA at 50 μg DNA ml−1 of the strainS induced the secretion of IL-12 (p70), IFN-γ and TNF-α by PBMCs. NK cell activities increased after cultivation
of PBMCs with live bacteria, cell wall and DNA of the strains. Overall, these results demonstrate that the live bacteria,
cell wall and genomic DNA of the two Lactobacillus strains exhibit immunomodulating activity. 相似文献
14.
Denis V. Abramochkin Natalia V. Tennova Elizaveta E. Hirazova Anna V. Pizgareva Vladislav S. Kuzmin Galina S. Sukhova 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(5):645-651
Standard microelectrode technique was used to study electrical activity of the isolated heart of the polychaete annelid, Arenicola marina. Typical pacemaker activity with slow diastolic depolarization was observed in all recordings. The average maximum diastolic
potential (−58.4 ± 3.2 mV), the average amplitude of the action potential (28.7 ± 4.7 mV) and the average total duration of
the action potential (2,434 ± 430 ms) were determined. There has been no gradient of automaticity observed in our studies,
which suggests that all regions of the Arenicola heart could possess pacemaker functions. Acetylcholine (ACh) produced a concentration dependent (5 × 10−8–5 × 10−5 M) increase of the beating rate via increase in the rate of the diastolic depolarization. ACh (5 × 10−5 M) increased beating rate by 2.5-fold compared to the control rate. A stronger action of ACh resulted in depolarization,
block of action potential generation and contracture of the heart. The non-hydrolysable ACh analog carbacholine (10−8–10−6 M) produced similar effects. All effects of ACh and carbacholine were abolished by 5 × 10−6 M atropine. d-Tubocurarine (5 × 10−5 M) did not significantly alter effects of ACh or carbacholine. Epinephrine (10−8–10−6 M) caused the slowing of pacemaker activity and marked decrease of action potential duration. 10−6 M epinephrine produced complete cardiac arrest. The effects of epinephrine were not significantly altered by the β-blocker
propranolol (5 × 10−6 M). The β-agonist isoproterenol (10−7–10−5 M) and the α-agonist xylometazoline (10−6–10−5 M) did not produce significant effects. Thus, cholinergic effects in the Arenicola heart are likely to be mediated via muscarinic receptors, while the nature of adrenergic effects needs further investigation. 相似文献
15.
Junming Tang Jianing Wang Hongxian Song Yongzhang Huang Jianye Yang Xia Kong Linyun Guo Fei Zheng Lei Zhang 《Molecular biology reports》2010,37(4):1957-1969
Stromal cell-derived factor 1α (SDF-1) is not only a major chemotactic factor, but also an inducer of angiogenesis. The effects
of SDF-1α on the left ventricular remodeling in a rat myocardial infarction (MI) model were analyzed. Myocardial infarction
was induced by ligation of the left coronary artery in rats. 0.5 × 1010 pfu/ml AdV-SDF-1 or 0.5 × 1010 pfu/ml Adv-LacZ were immediately injected into the infarcted myocardium, 120 μl cell-free PBS were injected into the infarcted
region or the myocardial wall in control, and sham group, respectively. We found that AdV-SDF-1 group had higher LVSP and
±dP/dtmax, lower LVEDP compared to control or Adv-LacZ group. The number of c-Kit+ stem cells, and gene expression of SDF-1, VEGF and bFGF were obviously increased, which was associated with reduced infarct
size, thicker left ventricle wall, greater vascular density and cardiocytes density in infarcted hearts of AdV-SDF-1 group.
Furthermore, the expression of collagen type I and type III mRNA, and collagen accumulation in the infarcted area was lower,
which was associated with decreased TGF-β1, TIMP-1 and TIMP-2 expression in AdV-SDF-1 group. Conclusion: SDF-1α could improve
cardiac structure and function after Myocardial infarction through angiogenic and anti-fibrotic actions. 相似文献
16.
An DS Cui CH Sung BH Yang HC Kim SC Lee ST Im WT Kim SG 《Applied microbiology and biotechnology》2012,94(3):673-682
The gene encoding an α-l-arabinofuranosidase that could biotransform ginsenoside Rc {3-O-[β-d-glucopyranosyl-(1–2)-β-d-glucopyranosyl]-20-O-[α-l-arabinofuranosyl-(1–6)-β-d-glucopyranosyl]-20(S)-protopanaxadiol} to ginsenoside Rd {3-O-[β-d-glucopyranosyl-(1–2)-β-d-glucopyranosyl]-20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol} was cloned from a soil bacterium, Rhodanobacter ginsenosidimutans strain Gsoil 3054T, and the recombinant enzyme was characterized. The enzyme (AbfA) hydrolyzed the arabinofuranosyl moiety from ginsenoside
Rc and was classified as a family 51 glycoside hydrolase based on amino acid sequence analysis. Recombinant AbfA expressed
in Escherichia coli hydrolyzed non-reducing arabinofuranoside moieties with apparent K
m values of 0.53 ± 0.07 and 0.30 ± 0.07 mM and V
max values of 27.1 ± 1.7 and 49.6 ± 4.1 μmol min−1 mg−1 of protein for p-nitrophenyl-α-l-arabinofuranoside and ginsenoside Rc, respectively. The enzyme exhibited preferential substrate specificity of the exo-type
mode of action towards polyarabinosides or oligoarabinosides. AbfA demonstrated substrate-specific activity for the bioconversion
of ginsenosides, as it hydrolyzed only arabinofuranoside moieties from ginsenoside Rc and its derivatives, and not other sugar
groups. These results are the first report of a glycoside hydrolase family 51 α-l-arabinofuranosidase that can transform ginsenoside Rc to Rd. 相似文献
17.
The presence of dipole-dipole cross-correlated relaxation as well as unresolved E.COSY effects adversely impacts the accuracy
of 1
J
NH splittings measured from gradient-enhanced IPAP-HSQC spectra. For isotropic samples, the size of the systematic errors caused
by these effects depends on the values of 2
J
NHα
, 3
J
NHβ
and 3
J
HNHα
. Insertion of band-selective 1H decoupling pulses in the IPAP-HSQC experiment eliminates these systematic errors and for the protein GB3 yields 1
J
NH splittings that agree to within a root-mean-square difference of 0.04 Hz with values measured for perdeuterated GB3. Accuracy
of the method is also highlighted by a good fit to the GB3 structure of the 1H-15N RDCs extracted from the minute differences in 1JNH splitting measured at 500 and 750 MHz 1H frequencies, resulting from magnetic susceptibility anisotropy. A nearly complete set of 2
J
NHα
couplings was measured in GB3 in order to evaluate whether the impact of cross-correlated relaxation is dominated by the
15N–1H
α
or 15N–1H
β
dipolar interaction. As expected, we find that 2
J
NHα
≤ 2 Hz, with values in the α-helix (0.86 ± 0.52 Hz) slightly larger than in β-sheet (0.66 ± 0.26 Hz). Results indicate that under isotropic conditions, N–HN/N–H
β
cross-correlated relaxation often dominates. Unresolved E.COSY effects under isotropic conditions involve 3
J
HNHα
and J
NHα
, but when weakly aligned any aliphatic proton proximate to both N and HN can contribute.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Bifidobacteria can potentially be used for gene therapy. Here, we reported that 65% of the total hIFN-α2b produced from Bifidobacteria longum transformed with pBAD-SPIFN plasmids encoding a fusion protein of the arabinosidase signal peptide and human IFN-α2b (hIFN-α2b),
was secreted. For B. longum transformed with pBAD-IFN plasmids (hIFN-α2b without the signal peptide), only 15% of the total IFN-α2b was secreted and
western blotting and N-terminal amino-acid sequence analysis revealed cleavage of the arabinosidase signal peptide from the
secreted hIFN-α2b. Moreover, the active level of the secreted hIFN-α2b in the supernatant of B. longum transformed with pBAD-SPIFN plasmids was over 1,000 IU/ml commercial rhIFN-α2b. Hence, the arabinosidase signal peptide can
enhance the secretion efficiency of IFN-α2b from B. longum.
Q. Deng, W. Zeng and Z. Yu contributed equally to this work. 相似文献
19.
Michael J. Bosela 《Plant Cell, Tissue and Organ Culture》2009,98(3):249-261
The effects of β-lactam antibiotics (penicillin, carbenicillin and cefotaxime), cytokinins, and auxins including phenylacetic
acid, a β-lactam breakdown product, were evaluated during in vitro shoot morphogenesis in two hybrid aspens; P. tremuloides × P. tremula (XTTa) and P. x canescens × P. grandidentata (XCaG). Although different callus and shoot induction media were used for both hybrids, the β-lactams often engendered similar
responses. At concentrations of 1,000 mg l−1, carbenicillin adversely impacted shoot elongation and, to a lesser degree, shoot regeneration. Cefotaxime enhanced caulogenesis
for all of the concentrations evaluated (125–500 mg l−1) especially when the cytokinin thidiazuron was used for shoot induction. The shoots formed faster and in greater numbers;
and the improvements were significant (α = 0.05) for both hybrids. However, hyperhydricity was more problematic when cefotaxime was included in the media. The incidence
of shoot hyperhydricity for the XCaG hybrid was more than twice as great for the highest cefotaxime concentration evaluated
(500 mg l−1) than for the control (>90% vs. ~40%). Penicillin had an opposite effect. Hyperhydricity frequencies for the XCaG hybrid
were lower when the media were supplemented with penicllin and the reductions were statistically significant at concentrations
of 500–1,000 mg l−1. The effects of the antibiotics were generally not reproduced by the auxins (0.1–100 μM), including phenylacetic acid, or
the other potential β-lactam degradation products evaluated (e.g. phenylmalonic acid, aminopenicillanic acid). The antibiotics
may have affected shoot hyperhydicity indirectly via changes in the time course of shoot regeneration. 相似文献
20.
PA28 subunits of the mouse proteasome: primary structures and chromosomal localization of the genes 总被引:2,自引:0,他引:2
The 20S proteasome is a multi-subunit protease responsible for the production of peptides presented by major histocompatibility
complex (MHC) class I molecules. Recent evidence indicates that an interferon-γ (IFN-γ)-inducible PA28 activator complex enhances
the generation of class I binding peptides by altering the cleavage pattern of the proteasome. In the present study, we determined
the primary structures of the mouse PA28 α- and β-subunits. The deduced amino acid sequences of the α- and β-subunits were
49% identical. We also determined the primary structure of the mouse PA28 γ-subunit (Ki antigen), a protein of unknown function
structurally related to the α- and β-subunits. The amino acid sequence identity of the γ-subunit to the α- and β-subunits
was 40% and 32%, respectively. Interspecific backcross mapping showed that the mouse genes coding for the α- and β-subunits
(designated Psme1 and Psme2, respectively) are tightly linked and map close to the Atp5g1 locus on chromosome 14. Thus, unlike the LMP2 and LMP7 subunits, the IFN-γ-inducible subunits of PA28 are encoded outside
the MHC. The gene coding for the γ-subunit (designated Psme3) was mapped to the vicinity of the Brca1 locus on chromosome 11. A computer search of the DNA databases identified a γ-subunit-like protein in ticks and Caenorhabditis elegans, the organisms with no adaptive immune system. It appears that the IFN-γ-inducible α- and β-subunits emerged by gene duplication
from a γ-subunit-like precursor.
Received: 11 March 1997 相似文献