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J N Aronson

Publications and source records attributed to J N Aronson.

17 recordsLinked to original sources
PubMed1999

Preschoolers' understanding of pretense and presumption of congruity between action and representation.

In a series of 4 studies, A. S. Lillard's (1993) paradigm for studying preschoolers' understanding of pretense was replicated and systematically examined. The design varied the extent of the contradiction built into Lillard's format. Decreases in contradictory information yielded increases in the incidence of correct judgments indicative of an implicitly representational understanding of pretense. The findings present a challenge to A. S. Lillard's (1993) conceptual analysis of pretense and suggest that methods adopted from the classic false-belief paradigm of H. Wimmer and J. Perner (1983) may be inappropriate for assessing preschoolers' understanding of pretense.

Adolescent↗
PubMed1987

Toxic Trypsin Digest Fragment from the Bacillus thuringiensis Parasporal Protein.

Enzymatic digestion in vitro of the Bacillus thuringiensis protoxin presumably releases and activates the toxin in a manner analogous to that which occurs when a B. thuringiensis sporulated fermentation preparation passes through the midgut of a lepidopteran larva. Therefore, a sporulated culture of B. thuringiensis subsp. kurstaki (serotype 3a3b) HD-263 was treated with trypsin to release an activated toxin soluble in bicarbonate buffer. A 63-kilodalton protein, toxic to cabbage looper larvae (Trichoplusia ni) and to lepidopteran cells in culture, was purified to homogeneity from this trypsin digest. The larvicide, a glycoprotein containing 5% carbohydrate (wt/wt), was purified from the soluble B. thuringiensis trypsin digest by using ammonium sulfate precipitation, anion-exchange chromatography, and hydrophobic-interaction chromatography. Its amino acid composition was high in nonpolar residues and unusually low in lysine and histidine. The isoelectric point was 6.5, and the amino acid on the N terminus was identified as isoleucine. The toxin was only slightly soluble in aqueous buffers unless the chaotropic agent potassium thiocyanate was added. Partial characterization of the toxin indicated that it corresponds well with reported sequences deduced from cloned genes.

Journal Article↗
PubMed1970

Spermidine requirement for Bacillus thuringiensis ribosomes in cell-free phenylalanine incorporation.

A cell-free system from Bacillus thuringiensis was found to actively incorporate phenylalanine into hot trichloroacetic acid-precipitable material in the presence of synthetic polynucleotide, ribosomes, S-100 supernatant, an energy-generating system, and guanosine triphosphate. Phenylalanine incorporation was absolutely dependent on the presence of spermidine in addition to magnesium ions, even when highly purified ribosomes were used. The spermidine effect could not be attributed to inhibition of nucleases. The ribosomal and supernatant fractions from Escherichia coli and B. thuringiensis could be substituted for each other in this system. The spermidine requirement was shown to be limited to the B. thuringiensis ribosome fraction.

Amines↗
PubMed1965

Effects of m-Tyrosine on Growth and Sporulation of Bacillus Species.

Aronson, John N. (Arizona State University, Tempe), and Gerald R. Wermus. Effects of m-tyrosine on growth and sporulation of Bacillus species. J. Bacteriol. 90:38-46. 1965.-The aromatic amino acid analogue, dl-beta-(3-hydroxyphenyl)alanine (m-tyrosine), reduced sporulation of a strain of Bacillus subtilis to less than 5% of that of control cultures in a glucose-salts minimal medium. The mass-doubling time increased twofold, but maximal growth equivalent to that of control cultures was eventually attained. A decreased growth rate could be maintained in the presence of the analogue for more than 10 doublings, despite incorporation of m-tyrosine-2-C(14) in place of some of the protein phenylalanine. The organism proliferated to chain lengths of 10 to 15 cells. These cells persisted for many hours after maximal growth had been reached, in contrast to normal cultures which had begun to autolyze and sporulate. The response to m-tyrosine of strains of B. cereus, B. thuringiensis, and B. megaterium was like that of B. subtilis. In addition, B. thuringiensis and B. cereus converted m-tyrosine to dihydroxyphenylalanine, which was further oxidized to a melaninlike substance. Growth of a strain of B. stearothermophilus was not slowed by m-tyrosine, but a strain of Escherichia coli grew at a reduced rate.

Journal Article↗