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101.
The effects of some metal ions on amidolytic and fibrinogenolytic activities of highly purified human plasmin were investigated
in vitro. In the presence of Zn2+, Cu2+, Cd2+, and Au+ in the incubation mixture at the concentrations of 1×10−5−1×10−3
M, the anidolytic plasmin activity was strongly inhibited, whereas Ca2+ and Mg2+ at the same concentrations were not effective. The analysis of the kinetic study has shown that Zn2+ or Cu2+ acts as mixed-type inhibitors of plasmin activity. The inhibition of amidolytic plasmin activity by Zn2+ and Cu2+ was reduced in the presence of EDTA, histidine, or albumin. Incubation of plasmin with Zn2+ or Cu2+ (at the concentration of 5×10−4
M) resulted in complete loss of its proteolytic action on fibrinogen, whereas Cd2+ and Au+ under the same conditions only partially inhibited this process. 相似文献
102.
Ghrelin stimulates feeding when administered centrally and peripherally. The lateral hypothalamus (LH) is thought to mediate ghrelin-induced hyperphagia. Thus, we examined central mechanisms underlying feeding generated by LH ghrelin. We determined that 0.3nmol of LH-injected ghrelin was the lowest dose increasing food consumption and it induced Fos immunoreactivity (IR; a marker of neuronal activation) in feeding-related brain areas, including the hypothalamic paraventricular, arcuate, and dorsomedial nuclei, amygdala, and nucleus of the solitary tract. Also, LH ghrelin induced Fos IR in LH orexin neurons. We conclude that the LH, as part of larger central circuitry, integrates orexigenic properties of ghrelin. 相似文献
103.
Transcriptome analysis of root transporters reveals participation of multiple gene families in the response to cation stress 总被引:31,自引:4,他引:27
104.
Kašparová Jana Lisá Vera Tuček Stanislav Doležal Vladimír 《Neurochemical research》2001,26(8-9):1079-1084
We investigated whether amyloid--peptide (A1–42) has an effect on the elevations of the intracellular concentration of Ca2+ ions ([Ca2+]i) induced by depolarizations of NG108-15 cells and on related Ca2+ channels. A1–42 (10-1000 nM) had no immediate effect on depolarization-induced [Ca2+]i elevations. [Ca2+]i increases were slightly diminished in cells grown in the presence of 100 or 1000 nM A1–42. Nifedipine (1 M) reduced these elevations equally in cells grown in the absence or presence of A1–42. In contrast, the ability of -conotoxin GVIA to diminish the depolarization-induced [Ca2+]i responses became lost in cells grown in the presence of 100 nM A1–42. This indicates that the influx of calcium through the N-type Ca2+ channels was compromised by the chronic exposure of cells to a submicromolar concentration of A1–42, presumably because of impairement of their function or diminished expression. This may be important in the pathogeny of Alzheimer's dementia in view of the pivotal role of N-type Ca2+ channels in neurotransmitter release. 相似文献
105.
106.
Little is known about the biology and feeding ecology of Arctogadus glacialis (Peters, 1874), an endemic gadid fish species occurring circumpolarly in both ice-free and ice-covered Arctic seas. In this
study we analysed specimens sampled from bottom trawl and Agassiz trawl catches conducted at eight stations in water depths
from 115 to 490 m in the Northeast Water Polynya off Greenland in August 1990. Size composition and sex ratios were assessed
for 585 fish with standard lengths ranging from 7.8 to 34.5 cm. Median fish sizes at the stations ranged between 8.6 and 18.8 cm.
Quantitative stomach content analyses of a subsample of 175 specimens revealed that in the Northeast Water A. glacialis fed almost exclusively on pelagic prey. Truly benthic organisms were not found in the stomachs, and sympagic species were
rarely recorded. Overall, calanoid copepods were the major prey in terms of numbers. However, stomach contents varied considerably
between fish size groups. In terms of prey biomass, copepods dominated the diet of small fish (<12 cm), primarily occurring
at shallow stations (115–250 m), whereas amphipods and mysids were relatively more important for larger fish (>16 cm), which
dominated the catches at deep stations (360–480 m). The broad variety of diet composition indicated an opportunistic pelagic
feeding pattern.
Received: 6 November 1997 / Accepted: 11 May 1998 相似文献
107.
108.
Marita Westhrin Minli Xie Magnus ?. Older?y Pawel Sikorski Berit L. Strand Therese Standal 《PloS one》2015,10(3)
Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering. 相似文献
109.
Supriya D. Mehta Brock Donovan Kathleen M. Weber Mardge Cohen Jacques Ravel Pawel Gajer Douglas Gilbert Derick Burgad Greg T. Spear 《PloS one》2015,10(2)
BackgroundWe identified predominant vaginal microbiota communities, changes over time, and how this varied by HIV status and other factors in a cohort of 64 women.MethodsBacterial DNA was extracted from reposited cervicovaginal lavage samples collected annually over an 8–10 year period from Chicago Women’s Interagency HIV Study participants: 22 HIV-negative, 22 HIV-positive with stable infection, 20 HIV-positive with progressive infection. The vaginal microbiota was defined by pyrosequencing of the V1/V2 region of the 16S rRNA gene. Scheduled visits included Bacterial vaginsosis (BV) screening; clinically detected cases were referred for treatment. Hierarchical clustering identified bacterial community state types (CST). Multinomial mixed effects modeling determined trends over time in CST, by HIV status and other factors.ResultsThe median follow-up time was 8.1 years (range 5.5–15.3). Six CSTs were identified. The mean relative abundance (RA) of Lactobacillus spp. by CST (with median number of bacterial taxa) was: CST-1–25.7% (10), CST-2–27.1% (11), CST-3–34.6% (9), CST-4–46.8% (9), CST-5–57.9% (4), CST-6–69.4% (2). The two CSTs representing the highest RA of Lactobacillus and lowest diversity increased with each additional year of follow-up (CST-5, adjusted odds ratio (aOR) = 1.62 [95% CI: 1.34–1.94]; CST-6, aOR = 1.57 [95 CI: 1.31–1.89]), while the two CSTs representing lowest RA of Lactobacillus and higher diversity decreased with each additional year (CST-1, aOR = 0.89 [95% CI: 0.80–1.00]; CST-2, aOR = 0.86 [95% CI: 0.75–0.99]). There was no association between HIV status and CST at baseline or over time. CSTs representing lower RA of Lactobacillus were associated with current cigarette smoking.ConclusionsThe vaginal microbial community significantly improved over time in this cohort of women with HIV and at high risk for HIV who had regular detection and treatment referral for BV. 相似文献
110.
Aleksandra Delplanque Dominika Wawrzynczyk Pawel Jaworski Katarzyna Matczyszyn Krzysztof Pawlik Malcolm Buckle Marcin Nyk Claude Nogues Marek Samoc 《PloS one》2015,10(3)
Lanthanide-doped nanoparticles are of considerable interest for biodetection and bioimaging techniques thanks to their unique chemical and optical properties. As a sensitive luminescence material, they can be used as (bio) probes in Förster Resonance Energy Transfer (FRET) where trivalent lanthanide ions (La3+) act as energy donors. In this paper we present an efficient method to transfer ultrasmall (ca. 8 nm) NaYF4 nanoparticles dispersed in organic solvent to an aqueous solution via oxidation of the oleic acid ligand. Nanoparticles were then functionalized with single strand DNA oligomers (ssDNA) by inducing covalent bonds between surface carboxylic groups and a 5’ amine modified-ssDNA. Hybridization with the 5’ fluorophore (Cy5) modified complementary ssDNA strand demonstrated the specificity of binding and allowed the fine control over the distance between Eu3+ ions doped nanoparticle and the fluorophore by varying the number of the dsDNA base pairs. First, our results confirmed nonradiative resonance energy transfer and demonstrate the dependence of its efficiency on the distance between the donor (Eu3+) and the acceptor (Cy5) with sensitivity at a nanometre scale. 相似文献