Photosynthesis as a function of short day induction and gibberellic Acid treatment in bougainvillea "san diego red"

Short day induction in Bougainvillea “San Diego Red” increases photosynthetic rates in mature leaves; gibberellic acid treatments, which inhibit flowering, cancel the short day effect. These results lend support of a nutritional hypothesis that suggests that in Bougainvillea assimilate supply to the reproductive axis increases before floral initiation and during flower development.     

Control mechanisms regulating gene expression during normal differentiation of myeloid leukemic cells: Differentiation defective mutants blocked in mRNA production and mRNA translation

Regulation of gene expression during myeloid cell differentiation has been analyzed using clones of myeloid leukemic cells that differ in their competence to be induced to differentiate by the normal macrophage- and granulocyte-inducing protein MGI. Changes in the relative rate of synthesis for specific proteins were compared to changes in the relative amounts of corresponding translatable poly(A)⁺ mRNAs, assayed in the reticulocyte cell-free translation system, using two-dimensional gel electrophoresis. Of the 217 proteins which changed during MGI-induced differentiation of normally differentiating MGI⁺D⁺ leukemic cells, 136 could be identified as products of cell-free translation. Eighty-four percent of the 70 decreases in synthesis, most of which occurred early during differentiation, were not accompanied by a parallel decrease in the amount of translatable mRNA, but were accompanied by a parallel shift of the corresponding mRNAs from the polysomal to the monosomal and free mRNA fractions. These results indicate that most of the early decreases in the synthesis of proteins were translationally regulated. In contrast, 81% of the proteins which increased in synthesis and 71% of the proteins that were induced de novo were regulated at the level of mRNA production. Experiments with differentiation defective mutants have shown that they were blocked both at the level of mRNA production and mRNA translation. The data with these mutants have suggested that there were different subsets of translationally regulated proteins which were separately regulated. The translational blocks for several proteins in these mutant clones have also made it possible to identify additional translational sites of regulation for protein changes that were controlled at the level of mRNA production during normal differentiation. The results indicate that translational regulation may predominantly have a different function in cell differentiation than regulation by mRNA production, and that differentiation-defective mutants can be blocked at either level.     

Nuclear control of neurite induction in neuroblastoma cells

Induction of neurite formation in neuroblastoma cells by dibutyryl cyclic 3':5'-AMP (db-cAMP) or prostaglandin EI (PGE1) was enhanced after enucleation. Cells selected for resistance to db-cAMP were induced to form neurites by db-cAMP or PGE1 only after, but not before enucleation. Inhibition of protein synthesis inhibited neurite induction in nucleated, but not in enucleated cells, and enucleated cells were less sensitive to inhibition of neurite formation by concanavalin A (ConA). Colchicine, vinblastine and cytochalasin B (CB), compounds that interfere with the assembly of microtubules and microfilaments, inhibited induction in both types of cells. It is suggested that enucleation removes a nuclear inhibitor of neurite induction by db-cAMP and PGE1, and that neurite induction in nucleated cells requires that cAMP activates the assembly of microtubules and microfilaments and inactivates the nuclear inhibitor.     

An auto-anti-b in an a1b person. Serological studies.

The serum of a patient (Mr. Lat) with the regular blood group A1 B contains an anti-B reacting with all cells having a B antigen except Bx and cis AB. The anti-B reacts at 4 degrees C and occasionally at room temperature as shown by agglutination, absorption-eluction and by thermo-dynamic assays. The antibody is regarded as an irregular autoantibody belonging to the group of the so called "suppressed" or "latent" antibodies.     

Control of normal differentiation of myeloid leukemic cells. X. Glucose utilization,cellular ATP and associated membrane changes in D+ and D− cells

Glucose utilization, energy metabolism and associated membrane changes, have been studied in D⁺ myeloid leukemic cells that can be induced to undergo cell differentiation to mature granulocytes by incubation with the appropriate conditioned medium (CM) and in D^? myeloid leukemic cells that cannot be induced to differentiate to mature cells. Before incubation with CM, glycolysis and the glycolytic production of ATP were lower and the activity of the pentose cycle was higher in D⁺ than in D^? cells. ATP depletion induced a higher degree of agglutination by concanavalin A in D^? than in D⁺ cells, indicating a difference in their surface membrane. There were no detectable differences in the transport of glucose and the synthesis of sterols and fatty acids. After incubation with CM, the D⁺ cells, like normal granulocytes, showed a higher glycolysis, produced their ATP more through glycolysis than oxidative phosphorylation, became less dependent on the exogenous supply of glucose and oxygen and had a lower rate of sterol and fatty acid synthesis. The differentiating D⁺ cells also showed a change in their surface membrane resulting in an increased agglutinability without a change in ATP content and a stimulation of the pentose cycle by concanavalin A. These properties, which were not acquired by D^? cells, were found before most of the D⁺ cells had differentiated to mature granulocytes. The data indicate, that the block in the ability of the D^? cells to differentiate and the acquisition of the metabolic properties of normal granulocytes by differentiating D⁺ cells, were associated with differences in the organization of the cell surface membrane.     

Evidence for more than one Ia antigenic specificity on molecules determined by the I-A subregion of the mouse major histocompatibility complex.

Ia antigenic specificities determined by the I-A subregion of the mouse major histocompatibility complex have been examined in strain B10.D2 (H-2d), C57BL/10 (H-2b), and in a (C57BL/6xDBA/2) hybrid (BDF1; H-2b/d). Detergent solubilized, 3H-leucine-labeled antigen preparations were mixed with appropriate alloantisera and precipitation was induced either by addition of goat anti-mouse gamma-globulin or by addition of protein A-bearing Staphylococci. Sequential precipitation analysis showed that in strain B10.D2, Ia specificities 8 and 11 were co-precipitable, and that in strain C57BL/10, Ia specificities 8 and 9 were co-precipitable. In contrast, precipitation of specificities 9 and 11 from a BDF1 antigen preparation showed that these two Ia specificities were on separate molecules. The genetic implications of these data are discussed.     

Control of normal differentiation of myeloid leukemic cells. VI. Inhibition of cell multiplication and the formation of macrophages.

D+ but not D- myeloid leukemic cells can be induced by the appropriate conditioned medium or by serum from endotoxin treated mice, to undergo cell migration in agar, cell attachment to the surface of a Petri dish and differentiation to mature macrophages and granulocytes. Inhibition of cell multiplication by cytosine arabinoside, hydroxyurea, mitomycin C, thymidine, 5-bromodeoxyuridine, 5-iododeoxyuridine, 5-fluorodeoxyuridine or actinomycin D, but not by vinblastine or cycloheximide, induced cell migration, cell attachment to the Petri dish and the formation of macrophages in D+ cells. There was no induction of cell migration or formation of macrophages and a much lower induction of cell attachment in D- cells. The induction of these changes in D+ cells required protein synthesis and the inhibitors showed the same toxicity for D+ and D- cells. The results indicate, that the inhibitors induced specific surface membrane changes in D+ but not in D- cells.     

Quantitation of conductance pathways in antral gastric mucosa

The magnitude of cellular and shunt conductance of Necturus gastric antral mucosa was studied by (a) comparing the cellular PD response to transepithelial PD response during changes of ionic activity in the serosal bathing solution and (b) by measurement of current spread within the epithelial sheet. Using constant product KCl changes cellular resistance was 6,788 omegacm2 and shunt resistance was 1,803 omegacm2. Deletion of HCO3- from the serosal solution produced similar but quantitatively smaller changes in PD. Using HCO3- deletion cellular resistance was 7,338 omegacm2 and shunt resistance was 1,973 omegacm2. Measurement of current spead within the mucosa avoids changing ionic gradients yet gave very similar results; cellular resistance was 8,967 omegacm2 and shunt resistance was 2,947 omegacm2. The shunt contribution to transepithelial conductance ranged from 75.2 to 79.0%. Shunt selectivity was assessed using KCl dilution potentials, where mucosal dilution gave a small change in tissue PD compatible with an anion/cation selectivity ratio of 1.16 across the shunt, whereas serosal dilution effect was dominated by a PD change across the serosal membrane of the cell.     

Sugar transport by renal plasma membrane vesicles. Characterization of the systems in the brush-border microvilli and basal-lateral plasma membranes.

Uptake studies of D- and L-glucose were performed on vesicles derived from brush-border and basal-lateral membranes. The uptake of the sugars into the vesicles was osmotically sensitive and independent of glucose metabolism. In brush-border vesicles D-glucose but not L-glucose transport was Na+ -dependent, was inhibited by phlorizin, and showed a transitory vesicle/medium ratio greater than 1, in the presence of an initial Na+ gradient. Basal-lateral membranes take up D-glucose faster than L-glucose, but the D-glucose uptake is significantly less sensitive to sodium removal and only moderately inhibited by phlorizin as compared to the brush-border fraction.