排序方式: 共有108条查询结果,搜索用时 15 毫秒
71.
Tepfer D Garcia-Gonzales R Mansouri H Seruga M Message B Leach F Perica MC 《Transgenic research》2003,12(4):425-437
DNA transfer was demonstrated from six species of donor plants to the soil bacterium, Acinetobacter spp. BD413, using neomycin phosphotransferase (nptII) as a marker for homologous recombination. These laboratory results are compatible with, but do not prove, DNA transfer in nature. In tobacco carrying a plastid insertion of nptII, transfer was detected with 0.1 g of disrupted leaves and in oilseed rape carrying a nuclear insertion with a similar quantity of roots. Transfer from disrupted leaves occurred in sterile soil and water, without the addition of nutrients. It was detected using intact tobacco leaves and intact tobacco and Arabidopsis plants in vitro. Transfer was dose-dependent and sensitive to DNase, and mutations in the plant nptII were recovered in receptor bacteria. DNA transfer using intact roots and plants in vitro was easily demonstrated, but with greater variability. Transfer varied with plant genome size and the number of repeats of the marker DNA in the donor plant. Transfer was not detected in the absence of a homologous nptII in the receptor bacteria. We discuss these results with reference to non-coding DNA in plant genomes (e.g., introns, transposons and junk DNA) and the possibility that DNA transfer could occur in nature. 相似文献
72.
Ajduk M Mikulić D Sebecić B Gasparov S Patrlj L Erdelez L Skopljanac A Staresinić M Desković S Sosa T Sitić S 《Collegium antropologicum》2004,28(2):937-941
Gastrointestinal stromal tumors (GISTs) are characterized with diverse clinical presentations, including acute and chronic gastrointestinal bleeding, abdominal pain, presence of an intra-abdominal mass, anorexia, and intestinal obstruction. A 60-year-old obese woman presented as an acute abdominal emergency with right lower quadrant (RLQ) pain and tenderness, nausea and leukocytosis, all mimicking acute appendicitis. Laparotomy revealed a spontaneously ruptured GIST of the jejunum, which was localized to the RLQ due to postoperative adhesions following previous two cesarean sections and cholecystectomy. Complete surgical resection was performed, followed by an uneventful early postoperative course. 相似文献
73.
Lipopolysaccharide can modify differentiation and immunomodulatory potential of periodontal ligament stem cells via ERK1,2 signaling
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Tamara Kukolj Drenka Trivanović Ivana Okić Djordjević Slavko Mojsilović Jelena Krstić Hristina Obradović Srdja Janković Juan Francisco Santibanez Aleksandra Jauković Diana Bugarski 《Journal of cellular physiology》2018,233(1):447-462
Lipopolysaccharide (LPS) is a pertinent deleterious factor in oral microenvironment for cells which are carriers of regenerative processes. The aim of this study was to investigate the emerging in vitro effects of LPS (Escherichia coli) on human periodontal ligament stem cell (PDLSC) functions and associated signaling pathways. We demonstrated that LPS did not affect immunophenotype, proliferation, viability, and cell cycle of PDLSCs. However, LPS modified lineage commitment of PDLSCs inhibiting osteogenesis by downregulating Runx2, ALP, and Ocn mRNA expression, while stimulating chondrogenesis and adipogenesis by upregulating Sox9 and PPARγ mRNA expression. LPS promoted myofibroblast‐like phenotype of PDLSCs, since it significantly enhanced PDLSC contractility, as well as protein and/or gene expression of TGF‐β, fibronectin (FN), α‐SMA, and NG2. LPS also increased protein and gene expression levels of anti‐inflammatory COX‐2 and pro‐inflammatory IL‐6 molecules in PDLSCs. Inhibition of peripheral blood mononuclear cells (MNCs) transendothelial migration in presence of LPS‐treated PDLSCs was accompanied by the reduction of CD29 expression within MNCs. However, LPS treatment did not change the inhibitory effect of PDLSCs on mitogen‐stimulated proliferation of CD4+ and the ratio of CD4+CD25high/CD4+CD25low lymphocytes. LPS‐treated PDLSCs did not change the frequency of CD34+ and CD45+ cells, but decreased the frequency of CD33+ and CD14+ myeloid cells within MNCs. Moreover, LPS treatment attenuated the stimulatory effect of PDLSCs on CFC activity of MNCs, predominantly the CFU‐GM number. The results indicated that LPS‐activated ERK1,2 was at least partly involved in the observed effects on PDLSC differentiation capacity, acquisition of myofibroblastic attributes, and changes of their immunomodulatory features. 相似文献
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75.
Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria. 总被引:1,自引:0,他引:1
Sacha A F T van Hijum Slavko Kralj Lukasz K Ozimek Lubbert Dijkhuizen Ineke G H van Geel-Schutten 《Microbiology and molecular biology reviews》2006,70(1):157-176
Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and alpha-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with alpha-amylase enzymes (family GH13), with a predicted permuted (beta/alpha)(8) barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of alpha-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize beta-fructan polymers with either beta-(2-->6) (inulin) or beta-(2-->1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed beta-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either beta-(2-->6) or beta-(2-->1) linkages, degree and type of branching, and fructan molecular mass remain to be identified. 相似文献
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77.
Milena Aleksi Danijela Stanisavljevi Marija Smiljkovi Perica Vasiljevi Milena Stevanovi Marina Sokovi Dejan Stojkovi 《The Annals of applied biology》2019,175(2):228-235
Pyrimethanil, a synthetic fungicide widely used for the treatment of pre‐ and postharvest fungal diseases on different agricultural crops, was explored for its antifungal activity on different fungal strains. The effect of pyrimethanil on fungal ergosterol was tested by using Aspergillus niger as a model organism. Furthermore, it was investigated, if pyrimethanil can effectively reduce the appearance of Aspergillus rot in wounded cherry tomato fruits. The fungicide cytotoxic effect on different human cell lines was evaluated. In addition, its influence on cell proliferation was studied. A. niger was the most resistant fungal strain (MFC 1.88 μg μL?1) to the effect of pyrimethanil. Addition of ergosterol doubled the MFC on A. niger, indicating that the compound might interfere with ergosterol, main sterol of fungal cell membrane. Disease incidence of A. niger in wounded cherry tomato fruits was not detected with pyrimethanil treatment of 0.75 mg/wound. Some cytotoxic effects of pyrimethanil on human cell lines were recorded already at 50 ng μL?1, while the expression of Ki67 marker of proliferation was decreased with 150 ng μL?1. These results altogether indicate that pyrimethanil is effective in reducing various fungal pathogens, but further use of this fungicide should be reevaluated because of its cytotoxicity. 相似文献
78.
Jelena Krstić Slavko Mojsilović Sonja S Mojsilović Juan F Santibanez 《World journal of stem cells》2021,13(11):1696-1713
Bone regeneration is a tightly regulated process that ensures proper repair and functionality after injury. The delicate balance between bone formation and reso rption is governed by cytokines and signaling molecules released during the inflammatory response. Interleukin (IL)-17A, produced in the early phase of inflammation, influences the fate of osteoprogenitors. Due to their inherent capacity to differentiate into osteoblasts, mesenchymal stem/stromal cells (MSCs) contribute to bone healing and regeneration. This review presents an overview of IL-17A signaling and the leading cellular and molecular mechanisms by which it regulates the osteogenic differentiation of MSCs. The main findings demon strating IL-17A’s influence on osteoblastogenesis are described. To this end, divergent information exists about the capacity of IL-17A to regulate MSCs’ osteogenic fate, depending on the tissue context and target cell type, along with contradictory findings in the same cell types. Therefore, we summarize the data showing both the pro-osteogenic and anti-osteogenic roles of IL-17, which may help in the understanding of IL-17A function in bone repair and regeneration. 相似文献
79.
Mojsilović S Krstić A Ilić V Okić-Đorđević I Kocić J Trivanović D Santibañez JF Jovčić G Bugarski D 《Cell and tissue research》2011,346(3):305-316
The mouse is a suitable experimental model to study the biology of mesenchymal stem cells (MSCs), as well as to be used in
biocompatibility studies and tissue engineering models. However, the isolation and purification of murine MSCs is far more
challenging than their counterparts from other species. In this study, we isolated, expanded and characterized mouse MSCs
from bone marrow (BM-MSCs). Additionally, we analyzed the effects of two regulatory molecules, interleukin 17 (IL-17) and
basic fibroblast growth factor (bFGF), on BM-MSCs growth and elucidated the signaling pathways involved. The results revealed
that IL-17 increased the frequency of colony-forming units fibroblast (CFU-F) as well as the BM-MSCs proliferation in a dose-dependent
manner, while bFGF supplementation had no significant effect on CFU-F frequency but induced an increase in cell proliferation.
Their combined usage did not produce additive effects on BM-MSCs proliferation and even induced reduction in the number of
CFU-F. Also, the involvement of both p38 and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases
(MAPKs) signaling in proliferative activity of IL-17 and bFGF on murine BM-MSCs and, moreover, the increased co-activation
of a common signaling molecule, p38 MAPK, were demonstrated. Together, the data presented highlighted the role of IL-17 and
bFGF in murine BM-MSCs proliferation and pointed to the complexity and specificity of the signaling networks leading to MSCs
proliferation in response to different regulatory molecules. 相似文献
80.
Ovarian abscess in young sexually non-active girls can represent a diagnostic challenge. 15-years old girl was admitted to the Clinic for Gynaecology and Obstetrics under the suspicion of torsion of an ovarian cyst. Her clinical status deteriorated after the admission with development of acute abdomen. Laparoscopic exploration was performed and unilateral ovarian abscess was found without involvement of other pelvic structures. The surgical procedure was minimal invasive for a young girl and Salmonella staleyville was isolated from pus. Solitary ovarian abscess can be of hematogenous origin and the causative pathogens are different from pathogens usually involved in pelvic inflammatory disease. To avoid later fertility problems it is of great importance to treat infections in pelvic region correctly according to the isolated microorganism and that surgery is the least invasive. 相似文献