共查询到20条相似文献,搜索用时 15 毫秒
1.
D K Miller S Sadowski G Q Han H Joshua 《Prostaglandins, leukotrienes, and essential fatty acids》1989,38(2):137-143
In a search for new inhibitors of leukotriene formation, a methylene chloride extract of the plant Dalbergia odorifera (Jiangxiang) was found to be a potent inhibitor of LTC4 formation in AB-CXBG Mct-1 mastocytoma cells. Following LH-20 and reverse phase HPLC chromatography, two compounds were isolated that had potent LTC4 inhibitory activity: medicarpin and 6-hydroxy-2-(2-hydroxy-4-methoxyphenyl) benzofuran (IV) with IC50s of 0.5 and 0.05 microM respectively. IV was shown to be a specific inhibitor of 5-lipoxygenase with an IC50 against the soluble rat enzyme of 0.08 microM, whereas it was inactive against cyclooxygenase. In neutrophils IV inhibited LTB4 production at comparable concentrations but had no effect on neutrophil degranulation or adhesion. 相似文献
2.
该研究采用砂培法,以狗骨木(Swida wilsoniana)和南酸枣(Choerospondias axillaris)两种岩溶植物为研究对象,用不同钙离子(Ca~(2+))浓度(设为5、35、70、150、300 mmol·L~(-1)的5个水平)的营养液进行培养,研究其对两种植物的生长及酶活性的影响。结果表明:狗骨木和南酸枣的株高在5 mmol·L~(-1)时最大,之后随Ca~(2+)浓度上升呈下降趋势,南酸枣在300 mmol·L~(-1)时有所回升。两种植物的根、枝、叶生物量和总生物量随着Ca~(2+)浓度增加而减少。狗骨木叶、枝、根的生物量分配比率为根枝叶,南酸枣在35 mmol·L~(-1)时表现为根枝叶,其他在Ca~(2+)浓度下均为枝根叶,叶生物量分配少。狗骨木和南酸枣的丙二醛(MDA)含量在150 mmol·L~(-1)时最低,且狗骨木的低于南酸枣。钙胁迫下,与南酸枣相比,狗骨木维持较高的过氧化氢酶(CAT)活性和可溶性糖含量。两种植物在5和150 mmol·L~(-1)的Ca~(2+)浓度下各项指标处于较适水平,而在300 mmol·L~(-1)的高钙离子浓度下受到明显的胁迫,对比两种植物,狗骨木较南酸枣在高钙浓度下有更好的适应性。 相似文献
3.
Shrubs play a pivotal role in reversing desertification and in promoting ecological rehabilitation in severe environments. However, how the interactions between shrubs and their understorey species change during restoration remains unclear. Here, we report the results of an observational study conducted in the Mu Us Desert of northern China. This study explored how dune stabilization and the size of individual shrubs affect shrub–herb interactions. In particular, we aimed to determine how different life-history groups and performance indicators (e.g., biomass and richness) of subordinate species respond to shrub–herb interactions during dune stabilization. The shrub Artemisia ordosica had positive effects on understorey species in this dune system. The ability of the shrub to promote the growth of understorey species increased with dune stabilization, but decreased from small to large shrubs. This effect was due to an increase in the relative abundance and biomass of perennials and their higher sensitivity to the positive effects of the shrubs. In contrast, the ability of shrubs to improve the richness of understorey species decreased with dune stabilization, but increased from small to large shrubs. This effect occurred because perennials suffered high strain during recruitment in disturbed open patches of the semi-fixed dunes, particularly below small shrubs. Our results support the theory claiming that communities are sets of hidden interaction groups that have contrasting responses (neutral for annuals, but facilitative for perennials) to dominant neighbors in a single community, depending on their functional strategies. Furthermore, our study highlights the high efficiency of A. ordosica in facilitating ecological restoration of dry and disturbed sandy communities. 相似文献
4.
Michelini FM Ramírez JA Berra A Galagovsky LR Alché LE 《The Journal of steroid biochemistry and molecular biology》2008,111(1-2):111-116
Stromal keratitis resulting from ocular infection with Herpes simplex virus type 1 (HSV-1) is a common cause of blindness. This report investigates the antiviral and anti-inflammatory properties of two new synthetic stigmastane analogs in the experimental model of HSV-1-induced ocular disease in mice. (22S,23S)-22,23-dihydroxystigmast-4-en-3-one (1) and (22S,23S)-22,23-dihydroxystigmasta-1,4-dien-3-one (2) exhibited anti-HSV-1 activity in vitro and ameliorated the signs of murine herpetic stromal keratitis (HSK), although none of the compounds showed antiviral activity in vivo. We discuss that the improvement of HSK could be due to an immunomodulatory effect of both compounds. 相似文献
5.
Summary The activities of several enzymes involved in the oxidation of ethanol and in the formation of oxaloacetate from acetate were compared in the yeasts Saccharomyces cerevisiae, Hansenula anomala and Rhodotorula glutinis grown on glucose and acetate, respectively. The most striking differences in the regulation of enzyme activities were found for alcohol dehydrogenase, acetaldehyde dehydrogenase, and malate dehydrogenase. The activities of the other enzymes tested behaved rather similar; in all three yeast species the enzymes of the glyoxylic acid by-pass showed the most extensive increase of activity in cells grown on acetate. 相似文献
6.
Dimitrov JD Ivanovska ND Lacroix-Desmazes S Doltchinkova VR Kaveri SV Vassilev TL 《The Journal of biological chemistry》2006,281(1):439-446
Polyspecific antibodies represent a first line of defense against infection and regulate inflammation, properties hypothesized to rely on their ability to interact with multiple antigens. We demonstrated that IgG exposure to pro-oxidative ferrous ions or to reactive oxygen species enhances paratope flexibility and hydrophobicity, leading to expansion of the spectrum of recognized antigens, regulation of cell proliferation, and protection in experimental sepsis. We propose that ferrous ions, released from transferrin and ferritin at sites of inflammation, synergize with reactive oxygen species to modify the immunoglobulins present in the surrounding microenvironment, thus quenching pro-inflammatory signals, while facilitating neutralization of pathogens. 相似文献
7.
《Saudi Journal of Biological Sciences》2021,28(12):7090-7097
BackgroundAround 30% world population affected by acute and chronic pain due to inflammation and accidental injuries. Pain is a uncomfortable sensation and it reduce the patients’ life quality.ObjectiveThe present exploration focuses to explore the beneficial effects of butein on the different chemical and thermal-provoked nociceptive and inflammatory mice models.MethodologyThe nociception was induced to the Swiss mice using different chemical (formalin, acetic acid, glutamate, and capsaicin) and thermal (hot plate and tail immersion) methods. the mice were supplemented with 10, 15, and 20 mg/kg of butein and respective standard drugs like morphine, diclofenac sodium, and dexamethasone. The anti-inflammatory effects of butein was studied using carrageenan-provoked inflammation in mice.ResultsThe present findings clearly demonstrated that the butein was substantially lessened the different thermal and chemical provoked nociception in mice. The carrageenan-triggered paw edema and inflammatory cell infiltrations were appreciably suppressed by the butein treatment. The TNF-α, IL-1β, and IL-6 levels in the carrageenan-induced mice were effectively depleted by the butein.ConclusionAltogether, the present findings evidenced the potent antinociceptive and anti-inflammatory properties of the butein in different nociceptive mice models. 相似文献
8.
9.
Summary This study examines the role of canopy trees in the formation and maintenance of different herb microhabitats in a mixed mesophytic forest stand. Herb abundance and reproductive success were recorded in 54 circular plots under seven species of canopy trees and in 15 circular control plots>2 m from any tree. Soil moisture, soil nutrient levels, litter depth, and light intensity were measured in a subset of these plots. Ordination of plots by both herb relative abundance and by reproductive success of common species indicated that herb assemblages under most canopy tree species were similar to those away from trees. However, herb assemblages under Fagus grandifolia trees differed moderately from the others while plots under Quercus alba trees supported significantly different herb assemblages. Analyses of variance revealed that several herb species occurred at significantly closer mean distance to the base of Q. alba or Fagus trees or at higher densities under these tree species. Soils around Q. alba trees had significantly higher concentrations of calcium and sulfate ions, and higher pH than plots under other tree species and control plots. This correlated closely with Q. alba stemflow which had higher concentrations of calcium and sulfate ions and lower concentrations of hydrogen ions than stemflow from other trees at this site. The slightly lower soil pH near the base of Fagus trees may have been related to the high volumes of stemflow produced by this species. Stepwise regression showed significant correlations between abundances of five common herb species and soil nutrient patterns. Maintenance of spatial heterogeneity in forest floor resources by the presence of different species of canopy trees may therefore be important in the maintenance of diversity in these understory herb communities. 相似文献
10.
Abstract Glucose uptake and phosphorylating activities were studied in two strains of slow-growing Rhizobium: Rhizobium japonicum (USDAI-110) and cowpea Rhizobium (USDA3278). Cultured cells of both species actively took up glucose, and at least two systems appeared to be involved, whereas purified bacteroids of both species failed to accumulate glucose actively. In both cell types, glucose phosphorylation was ATP-dependent, and no evidence was obtained for a phosphoenolpyruvate-dependent glucose phosphotransferase system. 相似文献
11.
中药药渣的处理是中药制药的难题,本研究利用PacBio Sequel高通量测序对堆放2年与5年的消炎药药渣进行理化性质及真菌多样性研究,为重要药渣的利用提供依据。分别对堆放2年(New 1-New 3)及5年(Old 1-Old 3)各3个消炎药渣高通量测序,共检测到43 753条有效序列,堆放2年的药渣中共检测到4个门、86个属、126个种,节担菌纲、小丛壳目、曲霉属为优势类群。堆放5年的药渣中检测到3个门、49个属、59个种,Chaetomium novozelandicum及小囊菌科为优势类群。消炎药药渣功能组成分析发现,堆放2年的药渣中腐生型真菌占比67.7%、致病真菌占比32.3%;堆放5年的药渣中腐生型真菌占比96.8%,仅检测到极少数其他型真菌。堆放2年的药渣pH为4.9±0.2,含水量为49.2%;堆放5年的药渣pH为3.6±0.1,含水量为20.8%。结果表明,随着堆放时间的增加,药渣pH及含水量下降,真菌营养类型由腐生、致病与共生三者丰度相当转变为单一的腐生型,说明随着堆放时间的增加,腐生真菌丰度增加,药渣降解加快,研究结果为药渣的利用提供了一定依据。 相似文献
12.
Soils contain two different activities for oxidation of hydrogen 总被引:1,自引:0,他引:1
Abstract Hydrogen oxidation rates were measured in a neutral compost soil and an acidic sandy loam at H2 mixing ratios of 0.01 to 5000 ppmv. The kinetics were biphasic showing two different K m values for H2 , one at about 10–40 nM dissolved H2 , the other at about 1.2–1.4 μM H2 . The low- K m activity was less sensitive to chloroform fumigation than the high- K m activity. If sterile soil was amended with Paracoccus denitrificans or a H2 -oxidizing strain isolated from compost soil, it exhibited only a high- K m (0.7–0.9 μM) activity. It also failed to utilize H2 mixing ratios below a threshold of 1.6–3.0 ppmv H2 (160–300 mPa). A similar result was obtained when fresh soil samples were suspended in water, and H2 oxidation was determined from the decrease of dissolved H2 . However, H2 was again utilized to mixing ratios lower than 0.05 ppmv, if the supernatant of the soil suspension or the settled soil particles were dried onto sterile soil or purified quarz sand. Obviously, soils contain two different activities for oxidation of H2 : (1) a high- K m , high-threshold activity which apparently is due to aerobic H2 -oxidizing bacteria, and (2) a low- K m , low-threshold activity whose origin is unknown but presumably is due to soil enzymes. 相似文献
13.
Delayed-type hypersensitivity is mediated by a sequence of two different T cell activities 总被引:4,自引:0,他引:4
Classical 24- to -48 hr delayed-type hypersensitivity (DTH) skin reactions are preceded by an early skin swelling reaction that peaks 2 hr after challenge. The ability to elicit this early component of DTH is T cell dependent and is also dependent on tissue mast cells and release of serotonin, mainly from these mast cells. The current study presents pharmacologic and kinetic evidence that the late response depends on the occurrence of the early response. A variety of pharmacological agents known to deplete, prevent release of, or block the activity of serotonin, when given just before skin challenge, blocked both the early and late components of DTH, but had no effect when given (even repeatedly) after the occurrence of the early component. Thus, the serotonin-dependence of the 24-hr component of DTH represents a dependence on the early component in which serotonin release is required. A temporal dependence of the late component of DTH on the early component was also demonstrated. The early and late phases occur at different times in recipients of sensitized T cells, depending on the interval between transfer and challenge, but there is a fixed 10- to 12-hr gap. Delayed onset of the late component occurs in recipients challenged immediately after transfer and appears to be due to a delay in the onset of the early component. This delay can be abolished by adoptive cell transfer into mice that are able to elicit a normal early component because of prior transfer of T cells that are able to mediate just an early component. On the basis of these findings, we conclude that DTH consists of a cascade of events. T cells mediating the early aspect of DTH release antigen-specific factors that, upon encountering antigen activate local serotonin-containing cells, such as mast cells, to release serotonin, which opens gaps between adjacent endothelial cells. Through these interendothelial gaps a second T cell population enters the extravascular space and interacts with local antigen to induce the late response by releasing the chemoattractant lymphokines that are classically associated with DTH and that cause recruitment of bone marrow-derived circulating leukocytes to infiltrate the reaction site. The ability of the second T cell population to mediate the late component of DTH is independent of further release of serotonin. 相似文献
14.
E V Rowsell J A Carnie S D Wahbi A H Al-Tai K V Rowsell 《Comparative biochemistry and physiology. B, Comparative biochemistry》1979,63(4):543-555
1. A rough inverse correlation between liver serine dehydratase activity and species body size was observed with mammals. This was not found for glutamate, malate or lactate dehydrogenase, fumarase or aspartate-2-oxoglutarate aminotransferase. Serine dehydratase (and certain liver aminotransferases showing a similar species-size dependence) may have a role in the stimulation of heat production. 2. Cold-exposed rats showed a 3-4 fold increase in serine dehydratase activity. 3. No liver serine dehydratase was measurable in amphibia. 4. In mammals high liver serine-pyruvate aminotransferase is associated with a flesh-eating dietary habit. High activity was found in amphibia and goldfish. A gluconeogenic role is suggested. 相似文献
15.
N. V. Goncharov M. A. Terpilovskii V. I. Shmurak D. A. Belinskaya P. V. Avdonin 《Journal of Evolutionary Biochemistry and Physiology》2017,53(4):271-281
Enzymatic activities of three types of serum albumin—rat, bovine and human—were analyzed comparatively using a mathematical model. Kinetic and equilibrium constants of carboxylesterase and paraoxonase activities of albumin in Sudlow’s sites I and II were determined. The effects of specific ligands, ibuprofen and warfarin, on enzyme kinetics in these sites were studied. Ibuprofen was found to have an inhibitory effect both on carboxylesterase and paraoxonase albumin activities, whereas warfarin specifically inhibited only carboxylesterase albumin activity. 相似文献
16.
Antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of some Hedyotis species 总被引:1,自引:0,他引:1
The antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of seven Hedyotisspecies were investigated. The antioxidant activity was evaluated by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods while the radical scavenging activity was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The anti-inflammatory activity related to NO inhibition of the plant extracts was measured by the Griess assay while cytotoxicity were measured by the MTT assay against CEM-SS cell line. The antibacterial bioassay (against 4 bacteria, i.e. Bacillus subtilis B28 (mutant), Bacillus subtilis B29 (wild-type), Pseudomonas aeruginosa UI 60690 and methicillin resistant Staphylococcus aureus, (MRSA) was also carried out using the disc-diffusion method. All tested extracts exhibited very strong antioxidant properties when compared to Vitamin E (alpha-tocopherol) with percent inhibition of 89-98% in the FTC and 60-95% in the TBA assays. In the DPPH method, H. herbacea exhibited the strongest radical scavenging activity with an IC50 value of 32 microg/ml. The results from the Griess assay showed that the tested extracts are weak inhibitors of NO synthase. However, all tested extracts exhibited moderate cytotoxic properties against CEM-SS cell line giving CD50 values in the range of 21-41 microg/ml. In the antibacterial bioassay, the stems and the roots of H. capitellata showed moderate activity against the 4 tested bacteria while the leaves showed moderate activity towards B. subtilis B28, MRSA and P. aeruginosa only. The roots of H. dichotoma showed strong antibacterial activity against all 4 bacteria. All other extracts did not exhibit any antibacterial activity. 相似文献
17.
Fine root architecture, morphology, and biomass of different branch orders of two Chinese temperate tree species 总被引:8,自引:0,他引:8
We have limited understanding of architecture and morphology of fine root systems in large woody trees. This study investigated architecture, morphology, and biomass of different fine root branch orders of two temperate tree species from Northeastern China—Larix gmelinii Rupr and Fraxinus mandshurica Rupr —by sampling up to five fine root branch orders three times during the 2003 growing season from two soil depths (i.e., 0–10 and.10–20 cm). Branching ratio (R
b) differed with the level of branching: R
b values from the fifth to the second order of branching were approximately three in both species, but markedly higher for the first two orders of branching, reaching a value of 10.4 for L. gmelinii and 18.6 for F. mandshurica. Fine root diameter, length, SRL and root length density not only had systematic changes with root order, but also varied significantly with season and soil depth. Total biomass per order did not change systematically with branch order. Compared to the second, third and/or fourth order, the first order roots exhibited higher biomass throughout the growing season and soil depths, a pattern related to consistently higher R
b values for the first two orders of branching than the other levels of branching. Moreover, the differences in architecture and morphology across order, season, and soil depth between the two species were consistent with the morphological disparity between gymnosperms and angiosperms reported previously. The results of this study suggest that root architecture and morphology, especially those of the first order roots, should be important for understanding the complexity and multi-functionality of tree fine roots with respect to root nutrient and water uptake, and fine root dynamics in forest ecosystems. 相似文献
18.
A. Alimpić A. Knežević K. Šavikin M. Ćurčić D. Veličković T. Stević 《Plant biosystems》2017,151(6):1002-1011
This is the first report on the phenolic composition and biological activities of endemic species Salvia jurisicii Ko?anin (Lamiaceae) originating from Macedonia. Aerial parts of S. jurisicii were extracted with dichloromethane, ethyl acetate, methanol, ethanol and water. All extracts were tested spectrophotometrically for total phenolic and flavonoid contents, while their phenolic composition was analyzed using HPLC-DAD. The antioxidant activity of extracts was studied using 2,2-dyphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ferric reducing ability of plasma and ß-carotene bleaching assays. Being the most frequently used solvents for extraction of bioactive ingredients from medicinal plants, water and ethanol extracts were chosen for further testing of antimicrobial, cytotoxic and antineurodegenerative activities. More polar solvent extracts showed higher total phenolic content and lower flavonoid content. Ethanol and methanol extracts, followed by water extract exhibited the strongest antioxidant activity. Extracts showed antimicrobial activity against certain bacteria and micromycetes. The cytotoxicity assay showed slight toxicity to HCT-116 cell line. In the antineurodegenerative assays, the extracts performed lower inhibition of acetylcholinesterase and tyrosinase than standards. According to the results of this study, it can be inferred that more polar extracts of S. jurisicii were quantitatively richer in total phenolics, showing stronger antioxidant activity. Ethanol extract showed stronger biological activities comparing to water extract. 相似文献
19.
Ademola O. Olaniran Anthony I. Okoh Stella Ajisebutu Peter Golyshin Gbolahan O. Babalola 《International microbiology》2002,5(1):21-24
Two bacterial species isolated using enrichment culture techniques from the topsoil of a main refuse dumpsite in Nigeria
were assessed for their dehalogenation potentials. The bacterial isolates were identified as belonging to the Bacillus and Pseudomonas genera. Axenic cultures of the isolates utilized monochloroacetic acid (MCA), trichloroacetic acid (TCA), trichloromethane
(CHCl3) and tetrachloromethane (CCl4) as the sole source of carbon for growth up to a final substrate concentration of 0.1% (w/v). The mean generation times of
the isolates in all the growth media ranged significantly (P<0.05) from 2.41 to 10.04 h and were generally higher than that observed in glucose medium (1.46–1.51 h). The numbers of the
chloride atoms in the different organochlorides were negatively correlated with the ability of the organisms to degrade the
compounds. Dehalogenase specific activities of the cell-mediated cultures ranged from 0.1 to 0.96 μg ml–1 chloride release (mg protein)–1 h–1 and were significantly (P <0.05) higher than that of the cell-free extract [0.09–0.8 μg ml–1 chloride release (mg protein)–1 h–1]. The optimal pH of the dehalogenase activity was found to be 8.0, and the optimal temperature was between 30 and 35 °C.
Electronic Publication 相似文献
20.
Carbohydrate content and glycosidase activities following cold hardening in two grass species 总被引:1,自引:0,他引:1
The freezing resistance of the grass species Phleum pratense L. (timothy) and Phalaris arundinaces L. increases significantly after cold hardening. The content and composition of soluble carbohydrates were determined in the plants after short day treatment, cold hardening and dehardening. The amounts of mono-, di- and trisaccharides were reduced during the short day treatment, increased during cold hardening and decreased again during dehardening. The total amounts of soluble carbohydrates (mono-, di-, tri- and polysaccharides) were the same in hardened and dehardened plants, indicating that during hardening soluble polysaccharides (fructose polymers, fructans) were converted to mono- and oligosaccharides. Sucrose increased most after hardening conditions and, in P. arundinacea , a significant increase in 1-F-fructosylsucrose (isokestose) was also observed.
Invertase (β-fructofuranosidase. EC 3.2.1.26) activity increased following cold hardening and decreased following dehardening, while the α-galactosidase (EC 3.2.1.22) activity seemed to increase after dehardening. The glycosidases are probably involved in the mobilisation of polysaccharides during cold hardening. 相似文献
Invertase (β-fructofuranosidase. EC 3.2.1.26) activity increased following cold hardening and decreased following dehardening, while the α-galactosidase (EC 3.2.1.22) activity seemed to increase after dehardening. The glycosidases are probably involved in the mobilisation of polysaccharides during cold hardening. 相似文献