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Biomedical subjects

J J Bonner

Publications and source records attributed to J J Bonner.

43 records · Page 3Linked to original sources
PubMed1978

HLA phenotype frequencies in individuals with cleft lip and/or cleft palate.

The HLA types of 133 patients with cleft lip and/or cleft palate were determined. Caucasian patients with isolated cleft palate showed a possible association with HLA. Ten of 11 male patients had HLA--A2 as compared to one out of eight female patients (P less than 0.005). Caucasian males with cleft lip and cleft palate had a slight increased frequency of HLA--Aw24 (P = 0.07) and Mexican-American males with cleft lip and/or cleft palate showed an increase of antigen HLA-A28 (P = 0.07), though neither were statistically significant. Females with cleft lip and/or cleft palate from either racial group had no differences from the controls. The serum from 90 mothers of patients with cleft lip and/or cleft palate were reacted against their child's lymphocytes. Of these crossmatch tests, 12% were found to be positive. These preliminary results suggest that male patients with isolated cleft palate are worthy of further studies with respect of HLA associations.

Cleft Lip↗
PubMed1977

Ecdysone-stimulated RNA synthesis in salivary glands of drosophila melanogaster: assay by in situ hybridization.

3H-RNA was isolated from nuclei and cytoplasm of Drosophila melanogaster larval salivary glands after labeling in organ culture in the presence or absence of ecdysone. Hybridization to the sites of the ecdysone-induced puffs 74EF and 75B could be detected only if the RNA was labeled in the presence of ecdysone, while hybridization to the ecdysone-repressed puff 68C was found primarily in the cytoplasmic RNA sample labeled in the absence of ecdysone. Hybridization at the site of an ecdysone-insensitive puff, 50CD, was readily detectable in all RNA samples. RNA hybridizing to the unpuffed region 60D seemed to be restricted to the nucleus of salivary gland cells and was present at only a low level in cytoplasmic RNA samples. The data indicate that in situ hybridization can be used to detect specific hormone-induced changes in transcription.

Cell Nucleus↗
PubMed1977

Polytene chromosome puffing and in situ hybridization measure different aspects of RNA metabolism.

Direct autoradiography of Drosophila melanogaster polytene chromosomes which have incorporated 3H-uridine suggests that the chromosomal puffs are the most active sites of incorporation; that the puffs are not the only sites of incorporation; and that there are sites which do not incorporate at all. In situ hybridization of 3H-RNA from salivary gland nuclei labels all three types of chromosomal sites. Labeling by in situ hybridization is not proportional to labeling by direct autoradiography. The differences may be explained by several models. Nuclear RNA of salivary glands probably contains transcripts from multiply repeated genes; these transcripts may hybridize to many chromosomal sites. The data furthermore suggest that the phenomenon of puffing may not be a simple reflection of transcription rate, since several puffs hybridize RNAs with quite different metabolic characteristics.

Autoradiography↗
PubMed1976

Ecdysone-stimulated RNA synthesis in imaginal discs of Drosophila melanogaster. Assay by in situ hybridization.

Cytoplasmic RNA from imaginal discs of Drosophila melanogaster, labeled by uridine incorporation in organ culture, has been assayed by hybridization to cytological preparations of polytene chromosomes. RNA labeled during the early stages (first four hours) of ecdysone stimulation was compared to RNA labeled in the absence of the hormone. For the poly(A)-containing fraction (oligo-dT bound), several loci hybridize only RNA labeled in the presence of ecdysone; one locus hybridizes only control RNA. The majority of hybridizing loci are unaffected by the hormone. Of the loci hybridizing RNA not bound to oligo-dT, several appear specific for the ecdysone-treated sample, though most are labeled more heavily with this RNA than with the control. None of the ecdysone-sensitive loci visualized by in situ hybridization are the sites of salivary gland puffs induced by ecdysone on the same time scale.

Animals↗
PubMed1976

The effect of heat shock on RNA synthesis in Drosophila tissues.

Total RNA from Drosophila imaginal discs, labeled under conditions of heat shock, is analyzed by hybridization in situ to salivary gland polytene chromosomes. Grain densities over the hybridizing bands are compared, showing that the response to heat shock is similar for several disc types and fly stocks. Alteration of the culture medium used for labeling during heat shock results in the specific induction (in discs, salvary glands, or fat body) of one of the heat-shock loci to a level far beyond that normally seen. We discuss the implications of this specific induction regarding the mechanism of response. We also discuss the observed difference between transcription labeling of salivary gland chromosomes and labeling by in situ hybridization.

Culture Media↗
PubMed1972

Induction and regulation of chloroplast replication in mature tobacco leaf tissue.

Chloroplast replication was induced in mature tobacco leaf tissue (Nicotiana tabacum L.) by culturing leaf discs on a sterile medium composed of salts and sucrose. Chloroplast replicaton is greatly enhanced by the addition of kinetin to this medium. Kinetin also enhances cell enlargement, but cell division does not occur. Chloroplast replication is nonsynchronous and proceeds most rapidly when the cell enlargement rate decreases. Chloroplast replication is light-dependent, but cell enlargement occurs in both light and dark. Chloroplast replication resumes when discs cultured in the dark are returned to the light. It appears that chloroplast replication is related to cell expansion. The possibility of inducing synchronous replication of chloroplasts in tobacco cells is discussed.

Journal Article↗