A high-resolution meiotic mapping panel for the pericentromeric region of chromosome 10.

Familial multiple endocrine neoplasia type 2A (MEN 2A) is a dominantly inherited cancer syndrome characterized by tumors in tissues derived from the neural crest. The disease manifests as medullary carcinoma of the thyroid, pheochromocytoma, and hyperparathyroidism. The MEN2A locus has been mapped near the centromere of chromosome 10 by linkage analysis. Statistical analyses have not resolved the location of MEN2A among several close markers. We have used our family material to refine the positions of 36 identified and confirmed crossovers among the markers most closely linked to MEN2A. This high-resolution meiotic mapping panel will help order loci in this pericentromeric region and narrow the region in which MEN2A maps.     

A MODIFIED CELL WALL MUTANT OF THE RED MICROALGA RHODELLA RETICULATA RESISTANT TO THE HERBICIDE 2,6-DICHLOROBENZONITRILE1

The rigid component of the cell walls of red macroalgae, cellulose, is lacking in the red microalgae. Instead, the cells are encapsulated within an amorphous polysaccharide. These complex sul fated polysaccharides are composed of at least 10 different sugars, but their structure is not known, When the herbicide 2,6-dichlorobenzonitrile (DCB), a compound that specifically inhibits cellulose biosynthesis, was applied to cultures of the red microalga Rhodella reticulata upon inoculation, growth was inhibited. When added during the stationary phase of growth (after cell division had ceased), DCB did not affect cell number but it did inhibit polysaccharide production. A spontaneous mutant resistant to DCB was selected; it had physiological characteristics similar to those of the wild-type parent. The composition of the cell wall polysaccharide of the mutant was totally modified, being composed almost entirely (98% of its dry matter, as compared to 2.9% in the wild type) of methyl galactose, but retaining the same sulfate content. The molecular mass of the mutant polysaccharide was, however, similar to that of the wild-type parent (～6 × 10⁶ daltons), although its viscosity was significantly lower.     

The levels of cyclic GMP and glucose 1,6-diphosphate,and the activity of phosphofructokinase,in muscle from normal and dystrophic mice

A striking reduction in the levels of glucose 1,6-diphosphate and an increase in cyclic GMP were found in muscle from dystrophic mice. Concomitant to these changes, the allosteric activity of phosphofructokinase was found to be markedly reduced. These findings could offer an explanation for the observed reduction in glycolysis in the dystrophic muscle.     

Cellular changes in the bone marrow of Plasmodium berghei-infected mice: II. Blast transformation and phagocytosis

The present work is concerned with early cellular changes occurring during a malaria infection. Blast transformation by lymphoid cells and phagocytosis by adherent cells from the bone marrow was performed, using immune and nonimmune Balb/c mice. Nonadherent bone marrow cells from immune mice show an increased specific lymphoblast transformation. This increase was not observed during a lethal infection (PI). Adherent bone marrow cells were assayed for phagocytosis of parasitized (PE) or normal erythrocytes (NE). Cells from immune mice show an increase in phagocytosis of PE and NE. Cells from PI mice showed a decreased phagocytosis throughout the infection, beginning at Day 1 after challenge.     

Ecteinascidia turbinata extracts inhibit DNA synthesis in lymphocytes after mitogenic stimulation by lectins.

Aqueous ethanol extract of a tunicate which was previously found to exert antitumor and immunosuppressive activities in vivo was tested for its effect on normal human lymphocytes in vitro. The extract suppressed the uptake of tritiated thymidine by lymphocytes stimulated with mitogen. This suppressive effect did not require continuous presence of the extract. Treatment of lymphocytes prior to mitogenic stimulation resulted in suppressive effect. The fact that suppression by the extract could also be achieved 24 hr after exposure to mitogen, an interval which was found to suffice for the attainment of maximal commitment for blastogenic transformation indicates that Ete can act at a stage subsequent to the binding of the lectin and elicitation of a mitogenic signal(s).