Biochemical response of lymphoma cells to mitogenic stimulation by prolactin

A previous study showed that cultured Nb 2 node rat lymphoma cells stopped replicating when transferred to medium supplemented with horse serum instead of fetal calf serum; resumption of growth could be induced by the addition of prolactin or other lactogens. The present study shows that in the absence of prolactin cells accumulated early in the G1 phase from which, on stimulation by the hormone, they proceeded through the cell cycle in a synchronized fashion. Ornithine decarboxylase and S-adenosyl methionine decarboxylase activities were closely related to the proliferative status of the cells. In stationary cultures the enzyme activity was barely detectable; following the addition of prolactin, the levels increased over 100-fold and displayed well-defined changes as the cells proceeded through the cell cycle. The results suggest the lymphoma cells are very useful for studying biochemical events resulting from the interaction of a mitogenic polypeptide hormone and its target cell.

Somatic hybridization in Nicotiana: Segregation of organellar traits among hybrid and cybrid plants

Protoplasts from a nitrate reductase-deficient mutant of Nicotiana tabacum L. were fused with protoplasts from a stamen-less, cytoplasmically malesterile cultivar of tobacco containing the cytoplasm from N. suaveolens Lehm. Plants were regenerated from the fused protoplasts and characterized with respect to stamen development, chromosome number, and chloroplast composition. Of 29 regenerated plants, stamen production was restored in 26 plants and pollen production in 22. One plant was male sterile and two plants have never flowered. Analysis of the electrophoretic mobility of ribulose-1,5-bisphosphate carboxylase (RuBPcase) showed that 19 of the plants contained RuBPcase of the N. suaveolens type, six plants contained enzyme of the N. tabacum type, and four plants contained both types. Analysis of resistance to tentoxin in seedlings from 20 of the plants demonstrated that 14 had N. suaveolens-type chloroplasts, three had N. tabacum type, and three contained both types. Many of the plants which produced stamens and pollen still contained chloroplasts of the N. suaveolens type. Thus, the trait of cytoplasmic male sterility in tobacco is not an expression of the type of chloroplast genetic material.

Inheritance behavior of information coding for small subunit polypeptides of fraction 1 protein

In various genera of plants, the small subunit of fraction 1 protein is often composed of more than one kind of polypeptide; these differ in isoelectric points and amino acid composition. Previous analysis of numerous individual progeny of Nicotiana tabacum (two kinds of polypeptides), N. glauca + N. langsdorffii parasexual hybrids (three kinds) and other examples showed no change in F-1 protein composition as a consequence of alternation of generations. Experiments reported here show that absence of one number of each of the 24 different pairs of chromosomes in an N. tabacum monosomic series and also absence of the "S" pair in a nullisome did not affect F-1 protein composition. Absence of the "E" pair caused reduction in the amount of the least acidic of the two kinds of N. tabacum small subunit polypeptides. The question of how many individual progeny of self-fertile hybrids would have to be analyzed to detect segregation of genes coding for F-1 protein small subunit polypeptides, if segregation occurs, was answered by analysis of F1 hybrids between N. otophora and N. tomentosiformis, and two subspecies of N. suaveolens, together with their F2 progeny. In both cases, analysis of 16 progeny was sufficient to demonstrate a segregation pattern of two F1 hybrid type to one each of the two parental types. Therefore, in the absence of segregation, it is likely that coding information for different kinds of F-1 protein small subunit polypeptides is sequestered on heterologous chromosomes, as postulated in previous reports.

Nicotiana Chromosome Coding for a Specific Polypeptide of the Small Subunit of Fraction 1 Protein

Fraction 1 protein has been isolated from leaves of a male sterile Nicotiana tabacum plant containing an extra N. debneyichromosome. The extra chromosome induces appearance of a third polypeptide composing the small subunit of fraction 1 protein, which otherwise contains two polypeptides as is shown by analysis of numerous different cultivars of N. tabacum.

Evolution of fraction 1 protein in the genus Lycopersicon

The large- and small-subunit polypeptide composition of fraction 1 protein contained in seven species of Lycopersicon and Solanum pennellii was determined by electrofocusing. The eight species of protein had large subunits composed of three polypeptides separated by about 0.05 pH unit, but there was no difference in the isoelectric points of the clusters of three polypeptides. By this criterion, no surviving mutations have appeared in the extranuclear DNA coding for the cluster of large-subunit polypeptides during a period of evolution which generated the eight species of plants. The genus Lycopersicon appears to be much younger than its sister genus Nicotiana in the family Solanaceae, where four types of polypeptide clusters have evolved. Three different small-subunit polypeptides whose isoelectric points are coded by nuclear DNA have arisen among the seven Lycopersicon species, and L. hirsutum and S. pennellii have proteins containing single polypeptides and are therefore considered older than L. chilense, L. chimielewskii, and L. parviflorum, whose proteins contain two polypeptides. L. cheesemanii, L. pimpinellifolium, and L. esculentum (and probably L. peruvianum) seem to be the most recently evolved species since their fraction 1 proteins have small subunits composed of three polypeptides.

Chloroplast DNA distribution in parasexual hybrids as shown by polypeptide composition of fraction I protein

Sixteen different mature interspecific parasexual hybrids, produced by fusing leaf protoplasts of Nicotiana glauca (G) and N. langsdorffii (L), were analyzed for fraction I protein (ribulose-1,5-bisphosphate carboxylase/oxygenase) which consists of large subunit polypeptides coded by chloroplast DNA and small subunit polypeptides coded by nuclear DNA. All the hybrids showed the combined small subunits of both parents, thus confirming the hybridity of each of the fusion products. Fourteen of the hybrids displayed the large subunit electrofocusing pattern characteristic of only one parent (eight L and six G). From one hybrid callus, two plants were regenerated, of which one had exclusively L-type large subunit and the other had exclusively G. A single plant retained a mixture of L ang G chloroplast DNA's; this later yielded six F2 progeny from one branch, all of which were G type, and three asexual progeny from another branch, all of which had the L-type pattern. In all, 46 F2 progeny and 8 different F3s were analyzed and each of these, with few if any exceptions, showed the same single subunit type as the F1 and F2 parent hybrid plants. Reasons for the rapid sorting out of the chloroplast types are discussed.

Personality correlates of semantic habits in the deaf

The relationships between personality characteristics and semantic habits were explored with use of The Sixteen Personality Factory Questionnaire, Form E, and a measure of semantic habits. Ss were 102 deaf male and female college students. The results, analyzed separately by sex, showed a few significant relationships. Deaf males who were emotionally less stable and affected by feelings tended to prefer positive and negative evaluations. Relaxed, tranquil, and unfrustrated deaf males tended to neglect positive and negative evaluations and to prefer categorical responses to detail ones. Serious and sober deaf females tended to neglect negative evaluations.

Acoustic image in visual detection for deaf and hearing college students

To explore the role of acoustic factors in visual detection, this study employed 40 deaf and hearing Ss. Ss were requested to cancel all the letters "e" in a passage from Treasure Island. Results were analyzed in terms of probabilities of missing a pronounced or silent e and the e in the word "the." Hearing and hard of hearing Ss were more likely to miss silent e's than pronounced e's. There was no significant difference between silent and pronounced e's for the profoundly deaf. Deaf and hearing Ss missed significantly more e's in "the" than pronounced or silent e's. The deaf, when compared to the hearing Ss, were more efficient in detecting pronounced and silent e's. They did not differ significantly from the hearing Ss in detecting the e in "the."

Polypeptide composition of fraction I protein from Nicotiana glauca and from cultivars of Nicotiana tabacum, including a male sterile line

The polypeptide compositions of fraction I protein isolated from six collections of Nicotiana glauca and from ten cultivars of N. tabacum, as well as a polyploid series and a male sterile line, have been analyzed by isoelectric focusing in polyacrylamide gel slabs containing 8 M urea. Apart from the male sterile line, none of the plants showed any variation from the species pattern of polypeptides. Fraction I protein from the male sterile Burley 21 cultivar of N. tabacum contained the two small subunit polypeptides of N. tabacum and the three large subunit polypeptides of an Australian species, probably N. megalosiphon. This indicates a changed chloroplast genome in the male sterile line in comparison to the normal fertile N. tabacum.

Comparison of physical and immunological properties of plasma membranes of two mouse leukemia cell lines, P388 and L1210

A method for the isolation of the plasma membranes of the mouse leukemic cell P388 is described. The method includes surface labeling of the cell membrane with 125I. The 125I specific activity of the plasma membrane preparation is 10- to 13-fold higher than that of the cell homogenate; enzyme assays and electron microscopy further corroborate the purity of the P388 plasma membrane preparation. The predominant iodinated membrane proteins have molecular weights of 85,000, 66,000, and 13,000 daltons. Antibodies prepared against P388 and L1210 plasma membranes inhibit the growth of the corresponding cells in the absence of complement. They show cross-reactivity to each other but do not affect the growth of HeLa cells.