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161.
Romy Fischer Hajer Debbabi Michel Dubarry Prosper Boyaka Daniel Tomé 《Biochimie et biologie cellulaire》2006,84(3):303-311
In recent years, Lf has gained increasing interest as a result of its protective effects against a variety of diseases. While iron binding and interactions with mammalian receptors and microbial components are the best described mechanisms of action, recent studies have provided evidence that Lf properties may be related to immunoregulatory effects on Th1/Th2 cell activities. In vitro and in vivo experiments show that Lf is able to stimulate the differentiation of T cells from their immature precursors through the induction of the CD4 antigen. Studies performed under nonpathogenic conditions have shown distinct results with regard to the ability of Lf to support the proliferation and differentiation of Th cells into the Th1 or the Th2 phenotype. In addition, Lf plays different roles in diseases by affecting the Th1/Th2 cytokine balance in a manner dependent on the host's immune status. Thus, Lf could cause a Th1 polarization in diseases in which the ability to control infection or tumor relies on a strong Th1 response. Lf may also reduce the Th1 component to limit excessive inflammatory responses. Finally, Lf may provide protection against Th1- or Th2-induced diseases, such as autoimmune or allergic diseases, through correction of the Th1/Th2 imbalance. 相似文献
162.
Streptozotocin and Alloxan-based Selection Improves Toxin Resistance of Insulin-Producing RINm Cells
Konstantin O. Bloch Romy Zemel Olga V. Bloch Hagar Grief Pnina Vardi 《Experimental diabetes research》2000,1(3):211-219
The aim of our study was to develop a method for
selection of subpopulations of insulin producing
RINm cells with higher resistance to beta cell toxins.
Cells, resistant to streptozotocin (RINmS) and
alloxan (RINmA), were obtained by repeated exposure
of parental RINm cells to these two toxins,
while the defense capacity, was estimated by the
MTT colorimetric method, and [3H]-thymidine incorporation
assay. We found that RINmS and
RINmA displayed higher resistance to both streptozotocin
(STZ) and alloxan (AL) when compared to
the parental RINm cells. In contrast, no differences
in sensitivity to hydrogen peroxide were found
between toxin selected and parental cells. Partial
protection from the toxic effect of STZ and AL was
obtained only in the parental RINm cells after
preincubation of cells with the unmetabolizable 3-
O-methyl-glucose. The possibility that GLUT-2 is
involved in cell sensitivity to toxins was confirmed
by Western blot analysis, which showed higher
expression of GLUT-2 in parental RINm compared
to RINmS and RINmA cells. In addition to the
higher cell defense property evidenced in the
selected cells, we also found higher insulin content
and insulin secretion in both RINmS and RINmA
cells when compared to the parental RINm cells. In
conclusion, STZ and AL treatment can be used for
selection of cell sub-populations with higher cell defense properties and hormone production. The
different GLUT-2 expression in parental and re
sistant cells suggest involvement of GLUT-2 in
mechanisms of cell response to different toxins. 相似文献
163.
Romy Fleischer Michael Wiese Reinhard Troschütz Mario Zink 《Journal of molecular modeling》1997,3(8):338-346
Quantitative structure-activity relationships for piritrexim and analogues acting as inhibitors of tumour cell growth have been derived. First the Free-Wilson-method was used on a homologous training set of eight derivatives. The selection of variables important for the biological activity of the compounds was carried out with different multivariate methods as multiple linear regression, the partial least squares method und a genetic algorithm. The derivation of three-dimensional structure activity relationships started with a systematic conformational analysis of all compounds. For the conformations having minimal energy and being in agreement with the crystal structure of piritrexim charges were calculated with the AM1 hamiltonian. For the superimposition of the derivatives two methods were used: maximal similarity of the common substructure or of the molecular fields. A Comparative Molecular Field Analysis with steric and electrostastic fields identified regions important for the activity of the studied compounds independent of the chosen alignment and also correctly predicted the activity of two nonhomologous compounds. 相似文献
164.
165.
Nina Ihling Andreas Uhde Romy Scholz Christian Schwarz Lutz Schmitt Jochen Büchs 《Biotechnology progress》2020,36(2):e2911
Secretion of heterologous proteins into the culture supernatant in laboratory strains of Escherichia coli is possible by utilizing a Type I secretion system (T1SS). One prominent example for a T1SS is based on the hemolysin A toxin. With this system, heterologous protein secretion has already been achieved. However, no cultivations in a defined mineral medium and in stirred tank bioreactors have been described in literature up to now, hampering the broad applicability of the system. In this study, a mineral medium was developed for cultivation under defined conditions. With this medium, the full potential and advantage of a secretion system in E. coli (low secretion of host proteins, no contamination with proteins from complex media compounds) can now be exploited. Additionally, quantification of the protein amount in the supernatant was demonstrated by application of the Bradford assay. In this work, host cell behavior was described in small scale by online monitoring of the oxygen transfer rate. Scalability was demonstrated by stirred tank fermentation yielding 540 mg/L HlyA1 in the supernatant. This work enhances the applicability of a protein secretion system in E. coli and paves the way for an industrial application. 相似文献