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G Albrecht-Buehler

Publications and source records attributed to G Albrecht-Buehler.

40 records · Page 3Linked to original sources
PubMed1977

Daughter 3T3 cells. Are they mirror images of each other?

Using a new technique to visualize the tracks of moving 3T3 cells and combining it with the visualization of actin-containing microfilament bundles by indirect immunofluorescence (Lazarides, E. and K. Weber. 1974, Proc. Natl. Acad. Sci. U.S.A. 71:2268-2272), I present experiments which suggest that: (a) 30-40% of the pairs of daughter 3T3 mouse fibroblasts in noncloned cultures have mirror symmetrical actin-bundle patterns. (b) The angle between separating daughter cells is approx. 90 degrees or 180 degrees and seems related to the directions of certain actin-containing bundles. (c) Approximately 40% of separately moving daughter cells which did not collide with any other cell in the culture performed directional changes in a mirror symmetrical way. Both daughter cells entered the next mitosis at approximately the same time. I suggest that the actin-bundle pattern, the angle of separation, major directional changes during interphase, and the time of the next mitosis are predetermined by the parental cell.

Actins↗
PubMed1976

Filopodia of spreading 3T3 cells. Do they have a substrate-exploring function?

Freshly plated 3T3 cells send out radial projections or filopodia. We observed cells which happended to settle on glass near the borderline of a gold-plated area. When some of the filopodia contacted the gold-plated area and others the glass substratum and remained attached for a few minutes, lamellipodia then extended preferentially toward the gold-plated area. 1-2 h later, most of the cells were found in the gold-plated area. When the filopodia of a spreading 3T3 cell contacted another already spread 3T3 cell and also the glass substratum, the first lamellipodia extended preferentially towards the glass. These observations suggest a directionally differentiated extension of lamellipodia after the filopodia of a spreading 3T3 cell have contacted different substrates in their environment. Before filopodia contact a substrate, they perform a rapid "scanning" motion. Therefore, we suggest that the filopodia of a spreading 3T3 cell serve as organs which explore the nonfluid environment and react to a certain quality of the substrate that is presently unknown. Subsequently, they mediate the extension of lamellipodia into the direction in which this quality is found. The described phenomena are reversibly inhibited by Cytochalasin B at concentrations above 5 mug/ml although filopodia are produced.

Cell Adhesion↗
PubMed1976

A quantitative description of the extension and retraction of surface protrusions in spreading 3T3 mouse fibroblasts.

We suggest a method of quantitating the motile actions of surface protrusions in spreading animal cells in culture. Its basis is the determination of the percentage of freshly plated cells which produce particle-free areas around them on a gold particle-coated glass cover slip within 50 min. Studying 3T3 cells with this assay, we found that the presence of Na+, K+, Cl-, and Mg++ or Ca++ in a neutral or slightly alkaline phosphate or bicarbonate buffered solution is sufficient to support the optimal particle removal by the cells for at least 50 min. Two metabolic inhibitors, 2,4-dinitrophenol and Na-azide, inhibit the particle removal. If D-glucose is added along with the inhibitors, particle removal can be restored, whereas the addition of three glucose analogues which are generally believed to be nonmetabolizable cannot restore the activity. Serum is not required for the mechanism(s) of the motile actions of surface protrusions in spreading 3T3 cells. However, it contains components which can neutralize the inhibitory actions of bovine serum albumin and several amino acids, particularly L-cystine or L-cystein and L-methionine. Furthermore, serum codetermines which of the major surface extension, filopodia, lamellipodia, or lobopodia, is predominantly active. We found three distinct classes of extracellular conditions under which the active surface projections are predominantly either lamellipodia, (sheetlike projections), lobopodia (blebs), or filopodia (microspikes). The quantitated dependencies on temperature, pH and the inhibition by cytochalasin B or the particle removal are very similar in all three cases. Preventing the cells from anchoring themselves for 15-20 min before plating in serum-free medium seems to stimulate particle removal threefold.

Azides↗