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141.
Kallistatin reduces vascular senescence and aging by regulating microRNA‐34a‐SIRT1 pathway
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Youming Guo Pengfei Li Lin Gao Jingmei Zhang Zhirong Yang Grant Bledsoe Eugene Chang Lee Chao Julie Chao 《Aging cell》2017,16(4):837-846
Kallistatin, an endogenous protein, protects against vascular injury by inhibiting oxidative stress and inflammation in hypertensive rats and enhancing the mobility and function of endothelial progenitor cells (EPCs). We aimed to determine the role and mechanism of kallistatin in vascular senescence and aging using cultured EPCs, streptozotocin (STZ)‐induced diabetic mice, and Caenorhabditis elegans (C. elegans). Human kallistatin significantly decreased TNF‐α‐induced cellular senescence in EPCs, as indicated by reduced senescence‐associated β‐galactosidase activity and plasminogen activator inhibitor‐1 expression, and elevated telomerase activity. Kallistatin blocked TNF‐α‐induced superoxide levels, NADPH oxidase activity, and microRNA‐21 (miR‐21) and p16INK4a synthesis. Kallistatin prevented TNF‐α‐mediated inhibition of SIRT1, eNOS, and catalase, and directly stimulated the expression of these antioxidant enzymes. Moreover, kallistatin inhibited miR‐34a synthesis, whereas miR‐34a overexpression abolished kallistatin‐induced antioxidant gene expression and antisenescence activity. Kallistatin via its active site inhibited miR‐34a, and stimulated SIRT1 and eNOS synthesis in EPCs, which was abolished by genistein, indicating an event mediated by tyrosine kinase. Moreover, kallistatin administration attenuated STZ‐induced aortic senescence, oxidative stress, and miR‐34a and miR‐21 synthesis, and increased SIRT1, eNOS, and catalase levels in diabetic mice. Furthermore, kallistatin treatment reduced superoxide formation and prolonged wild‐type C. elegans lifespan under oxidative or heat stress, although kallistatin's protective effect was abolished in miR‐34 or sir‐2.1 (SIRT1 homolog) mutant C. elegans. Kallistatin inhibited miR‐34, but stimulated sir‐2.1 and sod‐3 synthesis in C. elegans. These in vitro and in vivo studies provide significant insights into the role and mechanism of kallistatin in vascular senescence and aging by regulating miR‐34a‐SIRT1 pathway. 相似文献
142.
Cloning, expression, purification, and characterization of the acid alpha-mannosidase from Trypanosoma cruzi 总被引:1,自引:0,他引:1
Vandersall-Nairn AS; Merkle RK; O'Brien K; Oeltmann TN; Moremen KW 《Glycobiology》1998,8(12):1183-1194
The acid alpha-mannosidase of Trypanosoma cruzi is a broad-specificity
hydrolase involved in the catabolism of glycoconjugates, presumably in the
digestive vacuole. We have cloned the alpha-mannosidase gene from a T.cruzi
epimastigote genomic library. The alpha-mannosidase gene was determined to
be single copy by Southern analysis, and similar sequences were not
detected in genomic digests of either Trypanosoma brucei or Leishmania
donovani. The coding region was subcloned into the Pichia pastoris
expression vector pPICZ, and alpha-mannosidase activity was detected in the
medium of induced cultures. The recombinant alpha- mannosidase demonstrated
a pH optimum, inhibition by swainsonine, Km, and substrate specificity
consistent with the characteristics of the alpha-mannosidase previously
purified from T.cruzi epimastigotes. The recombinant enzyme was purified
103-fold from the culture medium of Pichia pastoris and had a native
molecular mass of 359 kDa by gel filtration. A combination of SDS-PAGE,
deglycosylation with endo H, and NH2-terminal sequencing indicates that the
enzyme is originally synthesized as a homodimeric polypeptide that is
subsequently cleaved to form a heterotetramer composed of 57 and 46 kDa
subunits. A polyclonal antibody raised to the recombinant enzyme was shown
to immunoprecipitate the alpha-mannosidase from T.cruzi cell extracts and
will be used in future immunolocalization studies.
相似文献
143.
Meagan M. Hynes Matthew E. Smith Robert J. Zasoski Caroline S. Bledsoe 《Mycorrhiza》2010,20(4):265-274
Ectomycorrhizal (ECM) hyphal communities have not been well characterized. Furthermore, there have been few studies where
the ECM hyphal community is compared to fungi detected as sporocarps or ECM-colonized root tips. We investigated fungi present
as hyphae in a well-studied California Quercus–Pinus woodland. Hyphal species present were compared to those found as sporocarps and ECM root tips at the same site. Hyphae were
extracted from root-restrictive nylon mesh in-growth bags buried in the soil near mature Quercus douglasii, Quercus wislizeni, and Pinus sabiniana. Taxa were identified using PCR, cloning, and DNA sequencing of internal transcribed spacer and 28s rDNA. Among the 33 species
detected, rhizomorph-forming ECM fungi dominated the hyphal community, especially species of Thelephoraceae and Boletales.
Most fungi in soils near Quercus spp. and P. sabiniana were ECM basidiomycetes, but we detected two ECM ascomycetes and three non-mycorrhizal fungi. Many ECM species present as
hyphae were also previously detected at this site as sporocarps (18%) or on ECM root tips (58%). However, the hyphal community
was mostly dominated by different taxa than either the sporocarp or ECM root communities. 相似文献
144.
Green synthesis method is being increasingly used in the development of safe, stable, and eco-friendly nanostructures with biological resources. In this study, extracellular and intracellular synthesis of gold nanoparticles (AuNPs) was carried out using green algae Chlorella sorokiniana Shihira & R.W. Fresh algae were isolated and identified from Musaözü Pond located in the province of Eskişehir and then extraction process were performed. Optimization studies were studied using pH value, metal salt concentration, and time parameters for extracellular synthesis and using only time parameter for intrasellular synthesis. Since more controlled and optimum conditions can be achieved in the production of AuNPs by extracellular synthesis, these nanoparticles (NPs) were used for characterization and antifungal activity studies. Optical, physical, and chemical properties of synthesized NPs were characterized by UV visible spectrophotometer (UV-Vis), dynamic light scattering (DLS), Zetasizer, X-Ray diffraction (XRD), Fourier transform ınfrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM), ınductively coupled plasma mass spectrometer (ICP-MS) and transmission electron microscope (TEM) analysis. The optimum conditions for AuNPs synthesis were determined as 1 mM for HauCl4 concentration, 6 for pH value, and 60th min for time. AuNPs obtained from extracellular synthesis from C. sorokiniana extract are 5–15 nm in size and spherical shape. TEM images of extracellular synthesis show noticeable cell wall and membrane damages, cytoplasma dissolutions, and irregularities. AuNPs obtained by intracellular synthesis are in 20–40 nm size and localized in the cell wall and cytoplasm. These NPs exhibited significant antifungal activity against C. tropicalis, C. glabrata, and C. albicans isolates. AuNPs obtained by algae-mediated green synthesis have a significant potential for medical and industrial use, and this eco-friendly synthesis method can be easily scaled for future studies. 相似文献
145.
Nathan C. Emery Ellen K. Bledsoe Andrew O. Hasley Carrie Diaz Eaton 《Ecology and evolution》2021,11(4):1480
As we strive to lift up a diversity of voices in science, it is important for ecologists, evolutionary scientists, and educators to foster inclusive environments in their research and teaching. Academics in science often lack exposure to research on best practices in diversity, equity, and inclusion and may not know where to start to make scientific environments more welcoming and inclusive. We propose that by approaching research and teaching with empathy, flexibility, and a growth mind‐set, scientists can be more supportive and inclusive of their colleagues and students. This paper provides guidance, explores strategies, and directs scientists to resources to better cultivate an inclusive environment in three common settings: the classroom, the research laboratory, and the field. As ecologists and evolutionary scientists, we have an opportunity to adapt our teaching and research practices in order to foster an inclusive educational ecosystem for students and colleagues alike. 相似文献
146.
HÜSEYIN SÜMBÜL R. SÜLEYMAN GÖKTÜRK OLCAY DNÇ DÜEN 《Botanical journal of the Linnean Society. Linnean Society of London》2003,141(2):251-254
A new species of Helichrysum Gaertn., H. orbicularifolium Sümbül, R. S. Göktürk & O. D. Düşen sp. nov. , is described and illustrated. The species is restricted to the south Anatolia Province, Antalya, Turkey, growing in humid calcareous rock crevices and on limestone cliffs. The species is compared with the closely related H. chasmolycicum . © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 251–254. 相似文献
147.
Contrasting seasonal patterns of fine root production for blue oaks (Quercus douglasii) and annual grasses in California oak woodland 总被引:1,自引:0,他引:1
In a blue oak woodland in NE California, we used root ingrowth cores to study seasonal patterns of fine root (< 2 mm diameter) production (FRP) for annual grasses and blue oaks (Quercus douglasiiHook and Arn.). At each of three sites (River, Upland and Hilltop) there were three studies: a short-term seasonal study, a long-term cumulative study and a core nutrient enrichment study. In the short-term study, ingrowth cores were installed and harvested in 3-month intervals. Grass and oak FRP dominated in different seasons. Grass FRP was greater in fall (Oct–Dec, 26.0 g m–2 month–1(gmm)) and winter (Jan–Mar, 18.1 gmm), lower in spring (Apr–Jun, 2.9 gmm) and negligible in summer (July–Sep). In contrast, oak FRP was greater in spring (6.1 gmm) with lower, but significant summer growth (2.9 gmm). Grass FRP declined steadily with soil depth (0–40 cm) in all seasons. Oak FRP changed little with soil depth, except in the summer, when production was greatest at lower soil depths. In the long-term study, ingrowth cores were installed and harvested after 3, 6, 9 and 12 months. Oak annual FRP was greater in the long-term study than in the short-term study at the River and Upland sites. Thus production in the short-term study may be an underestimate, due to disturbance effects. Nutrient enrichment of cores with N-P-K increased grass FRP, but surprisingly, decreased oak FRP, suggesting that annual grasses may have competitive advantages in nutrient enriched soil. 相似文献
148.
S. CASATI V. RACLOZ J. C. DELÉCOLLE M. KUHN A. MATHIS C. GRIOT K. D. C. STÄRK T. VANZETTI 《Medical and veterinary entomology》2009,23(2):93-98
In the past decade, there have been regular outbreaks of bluetongue (BT) in many parts of Europe. Owing to the presence of BT disease and its vectors in countries adjacent to Switzerland, an initial entomological survey was conducted in 2003, which established the presence of several midges of the genus Culicoides (Diptera: Ceratopogonidae). Subsequently, a sentinel herd monitoring system was established with the primary entomological aim being the determination and further study of Culicoides population compositions. Insects were collected in 2005 and 2006 at seven sentinel herd sites in the south of Switzerland (canton of Ticino) near the border of Italy, using Onderstepoort-type light traps. This region is botanically and zoologically similar to the Mediterranean and is one of the warmest and most humid areas of the country, hence it is considered a potential access path for BT disease into Switzerland. Collections were made at four cattle farms, two equestrian centres and one goat farm. Sites were sampled four times per month from June to October. Traps were operated from dusk until dawn and samples were collected monthly for analysis through microscopy as well as a Culicoides imicola -specific PCR. Results confirmed the absence of C. imicola (Kieffer) and demonstrated that the potential BT virus vectors are highly abundant, notably: Culicoides obsoletus (Meigen), Culicoides scoticus (Downes & Kettle) and Culicoides dewulfi (Goetghebuer) subgenus Avaritia and Culicoides pulicaris (Linnaeus) subgenus Culicoides . These findings expand the current knowledge of Culicoides population composition in the southern part of the Switzerland. Culicoides cataneii (Clastrier), Culicoides flavipulicaris (Dzhafarov), Culicoides indistinctus (Khalaf), Culicoides nubeculosus (Meigen) and species of the Grisescens complex were reported for the first time in Switzerland. 相似文献
149.
Accessing genetic diversity for crop improvement 总被引:1,自引:0,他引:1
150.