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51.
María álvarez-Viejo Yolanda Menéndez-Menéndez Jesús Otero-Hernández 《World journal of stem cells》2015,7(2):470-476
Mesenchymal stem cells, due to their characteristics are ideal candidates for cellular therapy. Currently, in culture these cells are defined by their adherence to plastic, specific surface antigen expression and multipotent differentiation potential. However, the in vivo identification of mesenchymal stem cells, before culture, is not so well established. Pre-culture identification markers would ensure higher purity than that obtained with selection based on adherence to plastic. Up until now, CD271 has been described as the most specific marker for the characterization andpurification of human bone marrow mesenchymal stem cells. This marker has been shown to be specifically expressed by these cells. Thus, CD271 has been proposed as a versatile marker to selectively isolated and expand multipotent mesenchymal stem cells with both immunosuppressive and lymphohematopoietic engraftment-promoting properties. This review focuses on this marker, specifically on identification of mesenchymal stem cells from different tissues. Literature revision suggests that CD271 should not be defined as a universal marker to identify mesenchymal stem cells before culture from different sources. In the case of bone marrow or adipose tissue, CD271 could be considered a quite suitable marker; however this marker seems to be inadequate for the isolation of mesenchymal stem cells from other tissues such as umbilical cord blood or wharton’s jelly among others. 相似文献
52.
Porphyra haitanensis is one of the most economical nutritive marine algae; however, its production and quality are significantly jeopardized by
high temperatures. Selection of heat-resistant strains will greatly reduce the economic risks and benefit to the nori industry.
Three previously isolated and improved strains with a high yield were screened at 28°C and identified, of which one strain,
ZS-1, showed significantly improved heat tolerance. Upon further characterizing of the cultures of the ZS-1 strain and the wild-type (WT) strain at 28°C and 30°C, the ZS-1 conchospore germlings survived at rates of 69.9% and 59.6%, while the WT conchospore germlings survived at significantly lower rates of 15.9% and 6.7%, respectively, over a period of 15 days. Furthermore,
ZS-1 conchospore germlings divided at significantly higher rates of 100% and 88.6% compared to the WT conchospore germlings with 90.4% and 63.8%, respectively. When the 35-day-old conchospore germlings were transferred from
the optimal temperature of 24°C to higher temperatures of 28°C and 30°C, the ZS-1 blades sustained growth over a 25-day period without decay and increase of blade lengths with a factor of 18.5 and 10.3 times,
respectively. The blade lengths of the WT germlings only increased by a factor of 1.7 and 0.9 times and began to decay after being cultured for 15 days at 28°C and
30°C. At 24, 28, and 30°C, the ZS-1 blades grew 3.4, 8.6, and 8.0 times faster than those of the WT. Evidently, ZS-1 is a fast-growing and heat-resistant strain compared to the WT strain and may offer an alternative for the nori industry. 相似文献
53.
This work aimed to evaluate a method to detect the residual ricin in animal tissues. Immunoprecipitation and sandwich enzyme-linked immunosorbent assay (ELISA) were used to detect ricin in the tissues of intoxicated mice. The monoclonal antibodies (Mabs) 4C13 and 3D74 were used to assay the whole ricin molecules via sandwich ELISA. Mab 4C13 was conjugated with Sepharose 4B to capture ricin or ricin A chain by immunoprecipitation. Mice injected intravenously with ricin at the dosage of 5 μg/mouse were killed at different time points after intoxication. The serum, liver, kidney, lung, and intestine were harvested. High levels of ricin were found in serum and liver samples at each poisoning time point by sandwich ELISA, suggesting the possibility of determining ricin intoxication by detecting residual ricin in the serum. However, this method turned out to be ineffective for examining ricin in the kidney, lung, and intestine of poisoned mice. Although the same tissue samples of intoxicated mice were analyzed by immunoprecipitation, positive bands were found. This indicated that some components in the kidney, lung, and intestine could bind with ricin and interfere in its binding activity with the coated antibody. Immunoprecipitation could be used to measure the existence of ricin in these samples. 相似文献
54.
目的:通过观察肝素钠对肢体缺血/再灌注(LI/R)过程中肠系膜微循环的动态变化和血液流变性的影响,探讨肝素减轻LI/R损伤的可能机制,为LI/R损伤的防治提供理论依据。方法:实验采用本室常规方法复制大鼠LI/R模型,正常雄性Wistar大鼠20只,随机分为2组(n=10):肝素组(H组)和单纯缺血/再灌注组(I/R组),两组动物均于再灌注损伤后2h时动态观察肠系膜微血管管径、血流速度、白细胞黏附、白微栓及微血管壁的完整性(管周出血)等情况,同时测定各组动物血液流变学指标和血清中P-选择素和细胞间粘附分子1(ICAM-1)的值。结果:肠系膜微动、静脉管径扩张,血流速度减慢,微血管中大量白细胞贴壁、粘附,白微栓形成增多,与I/R组比较,H组大鼠肠系膜微动脉血流速度(AFV)和微静脉血流速度(VFV)显著下降(P0.01);血浆黏度(ηp)、全血低切还原黏度(Lηre)、全血高切还原黏度(Hηre)、红细胞压积(Hct)、红细胞聚集指数(EAI)、血沉方程K值(ESRK)、红细胞刚性指数(TK)均显著下降(P0.01);红细胞变形指数(EDI)显著升高(P0.01);血清中P-选择素、ICAM-1水平均显著下降(P0.01)。结论:肝素可能通过降低血清中P-选择素和ICAM-1的水平而改善肢体缺血/再灌注损伤大鼠的全身微循环状态。 相似文献
55.
Kristiansen M Deriziotis P Dimcheff DE Jackson GS Ovaa H Naumann H Clarke AR van Leeuwen FW Menéndez-Benito V Dantuma NP Portis JL Collinge J Tabrizi SJ 《Molecular cell》2007,26(2):175-188
The mechanism of cell death in prion disease is unknown but is associated with the production of a misfolded conformer of the prion protein. We report that disease-associated prion protein specifically inhibits the proteolytic beta subunits of the 26S proteasome. Using reporter substrates, fluorogenic peptides, and an activity probe for the beta subunits, this inhibitory effect was demonstrated in pure 26S proteasome and three different cell lines. By challenge with recombinant prion and other amyloidogenic proteins, we demonstrate that only the prion protein in a nonnative beta sheet conformation inhibits the 26S proteasome at stoichiometric concentrations. Preincubation with an antibody specific for aggregation intermediates abrogates this inhibition, consistent with an oligomeric species mediating this effect. We also present evidence for a direct relationship between prion neuropathology and impairment of the ubiquitin-proteasome system (UPS) in prion-infected UPS-reporter mice. Together, these data suggest a mechanism for intracellular neurotoxicity mediated by oligomers of misfolded prion protein. 相似文献
56.
Song WS Kim HM Kim JH Sim SH Ryou SM Kim S Cha CJ Cunningham PR Bae J Lee K 《Journal of microbiology (Seoul, Korea)》2007,45(5):418-421
The nucleotide at position 791(G791) of E. coli 16S rRNA was previously identified as an invariant residue for ribosomal function. In order to characterize the functional role of G791, base substitutions were introduced at this position, and mutant ribosomes were analyzed with regard to their protein synthesis ability, via the use of a specialized ribosome system. These ribosomal RNA mutations attenuated the ability of ribosomes to conduct protein synthesis by more than 65%. A transition mutation (G to A) exerted a moderate effect on ribosomal function, whereas a transversion mutation (G to C or U) resulted in a loss of protein synthesis ability of more than 90%. The sucrose gradient profiles of ribosomes and primer extension analysis showed that the loss of protein-synthesis ability of mutant ribosomes harboring a base substitution from G to U at position 791 stems partially from its inability to form 70S ribosomes. These findings show the involvement of the nucleotide at position 791 in the association of ribosomal subunits and protein synthesis steps after 70S formation, as well as the possibility of using 16S rRNA mutated at position 791 for the selection of second-site revertants in order to identify ligands that interact with G791 in protein synthesis. 相似文献
57.
58.
Bioassays were performed to investigate the effects of the novel allelochemical, ethyl 2-methylacetoacetate (EMA), isolated
from the reed (Phragmitis australis) on the growth of three common species of algae; Scenedesmus obliquus, Selenastrum capricornutum and Chlamydomonas reinhardtii. The results demonstrated that EMA has three quite different types of effect on these three species of algae. The growth
of S. capricornutum was significantly inhibited by EMA during the whole cultivation period. The EC50 values of EMA on S. capricornutum was 0.6 mg L−1(7 days). However, the inhibitory effect of EMA on S. obliquus was apparent during the first 4 days of batch cultivation and then the inhibitory effect disappeared, and a stimulating effect
was observed instead. The EC50 value of EMA on S. obliquus was 0.43 mg L−1(4 days). In addition, following the addition of EMA, the cells of S. obliquus and S. capricornutum became significantly larger than the normal untreated one and the algal cells changed morphologically. The microstructure
of the algal cells was disrupted by the addition of EMA. There was no significant inhibition of the growth of C. reinhardtii by EMA, but cell motility was affected. 相似文献
59.
Marta Marcos-García Esther Menéndez Xavier Cruz-González Encarna Velázquez Pedro F. Mateos Raúl Rivas 《Symbiosis (Philadelphia, Pa.)》2015,67(1-3):11-20
The diversity of rhizobia that establish symbiosis with Lotus corniculatus has scarcely been studied. Several species of Mesorhizobium are endosymbionts of this legume, including Mesorhizobium loti, the type species of this genus. We analysed the genetic diversity of strains nodulating Lotus corniculatus in Northwest Spain and ten different RAPD patterns were identified among 22 isolates. The phylogenetic analysis of the 16S rRNA gene showed that the isolated strains belong to four divergent phylogenetic groups within the genus Mesorhizobium. These phylogenetic groups are widely distributed worldwide and the strains nodulate L. corniculatus in several countries of Europe, America and Asia. Three of the groups include the currently described Mesorhizobium species M. loti, M. erdmanii and M. jarvisii which are L. corniculatus endosymbionts. An analysis of the recA and atpD genes showed that our strains belong to several clusters, one of them very closely related to M. jarvisii and the remanining ones phylogenetically divergent from all currently described Mesorhizobium species. Some of these clusters include L. corniculatus nodulating strains isolated in Europe, America and Asia, although the recA and atpD genes have been sequenced in only a few L. corniculatus endosymbionts. The results of this study revealed great phylogenetic diversity of strains nodulating L. corniculatus, allowing us to predict that even more diversity will be discovered as further ecosystems are investigated. 相似文献
60.