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D Kobiler

Publications and source records attributed to D Kobiler.

44 records · Page 3Linked to original sources
PubMed1979

Extracellular lectin and its glycosaminoglycan inhibitor in chick muscle cultures.

Embryonic chick muscle contains two developmentally regulated lectins, which may be involved in cell interactions. These endogenous lectins are assayed as agglutinins of appropriate test erythrocytes. One of these, called lectin-2, interacts with specific glycosaminoglycans, especially heparin and dermatan sulfate. Lectin-2 is present at constant levels in both chick fibroblast and chick muscle cells throughout 14 days of culture but is released into the medium of cultured embryonic muscle after 7-8 days of culture, soon after myoblast fusion. Lectin-2 interacts strongly with a component of substrate-attached material in embryonic muscle cultures which is extractable from the cutlure dishes with alkali after the cells have been removed with ethylediaminetetraacetic acid. The active component in the substrate-attached material appears to be a glycosaminoglycan that is a more potent inhibitor of lectin-2 agglutination activity than any of the known glycosaminoglycans that we have tested. The active material is degraded by chondroitinase ABC but not by chondrotinase AC, hyaluronidase, or proteolytic enzymes and thus appears to be similar to dermatan sulfate. The results of these studies raise the possibility that lectin-2 functions by interacting with glycosaminoglycans, either associated with the cell surface or with the extracellular matrix.

Animals↗
PubMed1978

Distribution of an endogenous lectin in the developing chick optic tectum.

We determined the cellular localization of an endogenous lectin at various times during the development of a well-characterized region of chick brain, the optic tectum. This lectin is a carbohydrate-binding protein that interacts with lactose and other saccharides, undergoes striking changes in specific activity with development, and has previously been purified by affinity chromatography from extracts of embryonic chick brain and muscle. Cellular localization in the tectum was done by indirect immunofluoresecent staining, using immunoglobulin G derived from an antiserum raised against pure lectin. No lectin was detectable in the optic tectum examined at 5 days of embryonic development. From approximately 7 days of development, neuronal cell bodies and fibers were labeled by the antibody; and extracts of tectum contained hemagglutination activity that could be inhibited by lactose or by the antiserum. Lectin remained present in many tectal neuronal layers after hatching; but in 2-month-old chicks it was sparse or absent in most of the tectum except for prominent labeling of fibers in the stratum album centrale. The initial appearance of lectin in the optic tectum was not dependent on innervation by optic nerve fibers since bilateral enucleation during embryogenesis did not affect it. Lectin was detectable on the surface of embryonic optic tectal neurons dissociated with a buffer containing EDTA.

Animals↗
PubMed1977

Developmentally regulated lectin from embryonic chick pectoral muscle. Purification by affinity chromatography.

A lectin, whose specific activity in soluble extracts of embryonic chick pectoral muscle increases strikingly between 8 and 16 days of development, has been purified by affinity chromatography on derivatized Sepharose 4B coupled to p-aminophenyl-beta-D-lactoside. After affinity chromatography the lectin is pure except for minor contamination with another protein possibly representing a second muscle lectin. The latter can be completely removed by preparative isoelectric focusing. The purified lectin has an apparent molecular weight of 30,000 and an apparent subunit molecular weight of 15,000. Its isoelectric point is 4.0. The most potent saccharide inhibitors tested were thiodigalactoside and lactose. An antibody has been raised to the pure lectin. Studies with this antibody indicate that the lectin is present both on the surface of and within myoblasts.

Agglutinins↗
PubMed1977

Retrograde amnesia production by the intracisternal injection of 20 micronl of saline in rats.

The intracisternal injection of 20 micronl of saline into a rat within an hour after training it in an active avoidance response was found to induce retrograde amnesia. The results obtained by combining this procedure with the intracisternal injection of 2,6 Diaminopurine (DAP), which inhibits RNA synthesis and prevents long-term memory formation when administered at the proper time and in the correct dosage, suggest the existence of a medium term memory (MTM) mechanism. MTM was normally evident up to 75 min after training but was demonstrable up to 210 min when LTM formation was prevented by DAP.

2-Aminopurine↗
PubMed1976

The effect of antisynaptosomal plasma membrane antibodies on memory.

Antisynaptosomal plasma membrane antibodies were introduced through an infusion cannula into rat brain and their effects on behaviour were tested. Four different learning paradigms were used, two appetitively and two aversively motivated, to show impairment in memory retrieval. No effects were found on aquisition, motor activity, or motivation.

Animals↗