摘要:

It was found either in Western‐blot analysis or in indirect immunofluorescence microscopy that cells of the alga Chlamydomonas reinhardhi contain polypeptides cross‐reactng with antibodies directed against red blood cell spectrin. The protein could also be detected by immunoprecipitation with anti‐spectrin antibodies. C. reinhardtii cells contain distinct polypeptide chains reacting with antibodies directed against either α‐ or β‐ spectrin subunits. This protein was extracted from the cells with low ionic strength solution but was not with nonioni

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1048

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We have found that hydrogen peroxide (10−4− 10−2M) rapidly induces microvilli on separate cells and confluent sheets of human retinal pigment epithelium in culture. t‐butyl hydroperoxide and sodium arsenite do not induce microvilli. A role for hydrogen peroxide as an intercellular messenger has previously been proposed in the inflammatory response, in which hydrogen peroxide from phagocytes may signal to vascular endothelial cells. Our observations thus provide a second example of the induction of what may be a physiological response by this potentially toxic agent. In the retina, hydrogen peroxide released from illuminated photoreceptors may elongate the microvilli which extend into the spaces between them. Increased numbers of microvilli and their protrusion further into the photoreceptor layer may enhance various interactions between the two cell types, including the antioxidant functions of the epi

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1049

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

2,4‐dinitrophenol, dinitrophenol together with deoxyglucose, sodium azide and ouabain didn't alter cytoplasmic microtubule (MT) network of cultured PK (pig kidney embryo) cells, meanwhile they induced an increase in the average number of pericentriolar satellites and percentage of centrioles with the primary cilium in these cells. Also all drugs studied increase number of MTs attached to and oriented towards the centrosome. Under the action of ouabain the total number of MTs around the centrosome doubled, meanwhile the number of long MTs emanating from the centrosome increased more than 15 times. Under the action of all drugs studied, except sodium azide, the number of maternal centrioles oriented perpendicularly to the substrate surface increased significantly from that in control cell

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1050

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The role of cellular interactions in the resistance of Djungurian hamster cells to colchicine (CH) and in the efficiency of P‐glycoprotein function was studied. Mixtures of CH‐resistant and CH‐sensitive cells as well as control unmixed cells were propagated for 3 days and the sensitivity of the cells to CH was measured by colony forming assay. Identification of individual subpopulations was possible due to genetic marker (6TG‐resistance). The data show that the survival of CH‐sensitive cells in CH‐supplemented medium increased after co‐cultivation with CH‐resistant counterparts. To measure Pgp activity the fluorescent dye RH123 and FACScan analysis were used. Pgp‐mediated RH123 efflux increased after co‐cultivation of CH‐sensitive a

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1051

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Activity of phosphotyrosine ‐ protein phosphatases (PTPases) has been investigated in the different cellular regions of bovine eye lens. PTPases were tested in cellular detergent extracts using phospholabelled synthetic peptides and p‐nitrophenyl phosphate. We show that a high PTPase activity is only present in cells which undergo differentiation, namely the equatorial epithelium and cortex fiber cells. Since this activity is found to be severely inhibited by a specific inhibitor of receptor ‐ type PTPases, it can be suggested that one or more members of this class of PTPases might play an important role in the lens differentiation pr

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1052

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

In vitro human skin fibroblasts aging was characterized by a continuous increase of collagenase mRNA levels. On the contrary, TIMP‐1 mRNA level decreased only at late passages (>65% of proliferative life span). Type I and III mRNA levels showed a high variability depending on cell strains studied. However, type I and III collagen expressions varied parallely. All‐trans retinoic acid (RA) decreased collagenase expression and stimulated TIMP‐1 expression. Under RA action, high variability in mRNAs levels encoding type I and III collagens was observed with HSF passages. However, RA tended to correct variations in collagens expressions observed along HSF life

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1053

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

TPA treatment of sea urchin embryos is able to induce thermotolerance. Evidence is provided that TPA treatment induces phosphorylation of a constitutive stress protein of 38 KDa.

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1054

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Fluorescent reagent‐labelled PGCs isolated from the blood of 2‐day‐old chick embryos were cultured on stroma cells derived from 5‐day‐old germinal ridge in Medium 199 supplemented with 10% FBS, human IGF‐1, bovine FGF‐b, and murine LIF. In 7 experiments, the number of MCs increased by an average of 4.8 fold in 4 days. Intrinsic PGCs in the 5‐day embryonic germinal ridge were observed loosely attached to the stroma cells, and they also increased 3.8 fold during culture for 4 days. These results indicate the possibility of applying this culture method to the production of tran

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1055

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Chloride secretion in primary cultures of cells originating from the secretory coil of human sweat glands was investigated by electron probe X‐ray microanalysis. The total intracellular Cl concentration was lowered by muscarinic agonists (carbachol and acetylcholine), as well as by the calcium ionophore A23187. The muscarinic agonists also lowered the cellular K concentration. Cl−secretion induced by these agonists could be inhibited by the chloride channel blocker NPPB. After cAMP stimulation, the frequency distribution of the Cl concentration changed from Gaussian to bimodal, indicating that cAMP induces Cl−secretion only from a subpopulation of the cells. Also ATP stimulated Cl−secretion, indicating the presence of purinergic receptors. The results suggest that some of the cells in addition to Ca2+‐regulated Cl−channels also possess cAMP‐activated Cl−channels. Hence, the primary cultures still possess the Cl−transport mechanisms known to be present in intact glands. It can, however, not be excluded that some coil cells have acquired ductal characteristi

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1056

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1057

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY