LIGAND-INDUCED MOVEMENT OF LYMPHOCYTE MEMBRANE MACROMOLECULES : V. Capping, Cell Movement, and Microtubular Function in Normal and Lectin-Treated Lymphocytes

Capping of surface Ig by anti-Ig antibodies involves a membrane perturbation requiring an energy-dependent step. Lymphocytes treated with anti-Ig are stimulated to move. Previously, we had shown that movement was not essential for capping, although it influenced the localization of the cap. We have investigated the role of cell movement and of microtubular proteins in this phenomenon. Treatment of B lymphocytes with colchicine does not affect capping of Ig nor does it affect the increase in translational movement produced by anti-Ig antibodies. Treatment of lymphocytes with cytochalasin B stops translational movement and may affect capping to some degree under appropriate circumstances. Lymphocytes treated with both drugs are impaired in capping. We surmise that there may be two cytoplasmic events regulating directly or indirectly capping: one associated with the process of translational movement, the other associated with the activity of microtubules. Lymphocytes treated with concanavalin A do not cap Ig. Colchicine reverses this inhibition. Certain experimental procedures antagonize the colchicine effect, the most striking of which is the use of cytochalasin B. Colchicine appears to increase movement of the Con A-treated lymphocyte, and this increased movement appears responsible for the accumulation of complexes to the posterior part of the cell. Con A inhibits patching of Ig by anti-Ig, and this is not reversed by colchicine

LIGAND-INDUCED MOVEMENT OF LYMPHOCYTE MEMBRANE MACROMOLECULES : III. RELATIONSHIP BETWEEN THE FORMATION AND FATE OF ANTI-IG-SURFACE IG COMPLEXES AND CELL METABOLISM

Spleen lymphocytes were studied for the movement and interiorization of complexes of anti-Ig-surface Ig. The movement of the complex into a small, compact zone of the cell membrane (forming a cap) was inhibited by drugs that inhibited glycolysis and oxidative phosphorylation, but not by drugs that affected protein synthesis. Dead lymphocytes did not form caps. Freeze-etching techniques revealed that inhibited lymphocytes showed formation of multiple small complexes over the entire cell surface. Inhibitors of glycolysis and of oxidative phosphorylation also inhibited the interiorization and catabolism of radioiodinated anti-Ig. We hypothesize that cross-linking of all the surface Ig triggers the membrane movements that are required to pull the lattice into one zone of the cell

LIGAND-INDUCED MOVEMENT OF LYMPHOCYTE MEMBRANE MACROMOLECULES : I. ANALYSIS BY IMMUNOFLUORESCENCE AND ULTRASTRUCTURAL RADIOAUTOGRAPHY

The fate of different complexes on the membrane of thymocytes and spleen lymphocytes was studied with the use of both immunofluorescence and ultrastructural radioautography. The complexes of anti-immunoglobulin (Ig) with the surface Ig of B lymphocytes were present all around the membrane at 4°C; an increase in temperature produced a rapid aggregation of the complex into a cap which was readily interiorized in vesicles. Ultrastructural details of this process were given. The movement of the complexes depended upon the amount of anti-Ig and the temperature. The complexes of anti-lymphocyte antibody with surface antigen(s) did not result in formation of a single large aggregate (or cap) unless an anti-antibody was brought into the reaction. The caps formed by this trilayered complex were not interiorized. Concanavalin A (Con A) bound to cell surface carbohydrate moieties and the complexes of Con A readily formed a cap and were interiorized. Finally, antibodies to H-2 determinants did not form in most instances a single cap aggregate even when anti-antibodies were used. With time the H-2 complexes tended to form several large aggregates with some endocytosis

AN ULTRASTRUCTURAL STUDY OF LYMPHOCYTES WITH SURFACE-BOUND IMMUNOGLOBULIN

This report is on a radioautographic study of lymphocytes exposed to 125I-labeled anti-Ig in an attempt to identify surface-bound Ig molecules. The results as studied by ultrastructural radioautography confirmed the presence of surface-bound Ig on a certain population of lymphocytes. The specificity of the anti-Ig was determined by using appropriate controls that included the use of an absorbed anti-Ig and anti-hemocyanin antibody. The labeling pattern resulting from the interaction of labeled anti-Ig and Ig was found to be specifically associated with the cell surface and random in its distribution. Morphological differences were not apparent between labeled and nonlabeled lymphocytes in the spleen and lymph nodes. In the thymus, most lymphocytes did not exhibit detectable Ig. The few thymic lymphocytes that were labeled had unique morphological characteristics that included fewer ribosomes, many of which were monoribosomes. Relative to the amount in their cytoplasmic organelles, plasma cells had surface Ig but to a lesser degree than lymphocytes. Finally, macrophages were nonspecifically labeled and contained antibody on their membranes as well as intracellularly

Gender differences in adventure tourists who practice kayaking in Extremadura

Adventure tourism is among the sectors that has experienced the greatest growth in participation in recent years. In addition, it provides a unique opportunity to generate different benefits for rural populations as well as for the preservation of their environment. The objective of this study was to analyze gender differences in the profile, estimated expenditure, perception of economic impact and satisfaction of adventure tourists visiting the Valle del Jerte (Extremadura, Spain) for kayaking activities. The sample was composed of 511 tourists who kayaked in the Valle del Jerte. Gender differences were analyzed by the Mann-Whitney U test in continuous variables and Pearson’s chi-square test in categorical variables. The predominant profile of the kayaking tourist is Spanish, married, employed, with university education, lives with their partner with children at home, chooses a rural home for accommodation, travels with companions, uses their own car for transportation, spends 550 euros on average, has good perceptions of the economic impact of the activity on the destination and is satisfied with the kayak service received. This information is relevant for public and private organizations as well as for the local community to be able to offer services more oriented to the tourist who engages in these activities, as well as to attract more tourists

Gratitude at work prospectively predicts lower workplace materialism: A three-wave longitudinal study in Chile

Indexación ScopusMaterialism at work refers to a higher importance attached to extrinsic (e.g., money, fame, image) versus intrinsic (self-development, affiliation, community participation) employees’ ‘aspirations’. Research from self-determination theory has consistently found that materialism at work is strongly detrimental for both employees and organizations. For example, materialism is negatively associated with lower job satisfaction and engagement and positively associated with higher turnover intentions and job insecurity. Unfortunately, there are no viable strategies for reducing materialism in the workplace yet. In this sense, based on emergent research in psychology, we theorized that dispositional gratitude—a key construct within the Positive Organizational Psychology field—could be a protecting factor against materialism. Further, we conducted a three-wave longitudinal design among a large sample of Chilean workers (n = 1841) to test, for the first time, the longitudinal link between gratitude and materialism. We used two novel methodologies: A cross-lagged panel model (CLPM) to test between-person changes and a trait-state-occasion model (TSO) to test within-person changes. We found that both the CLPM as well as the TSO models showed that gratitude at work prospectively predicted further lower workplace materialism. Specifically, the CLPM shows that individuals with higher than average gratitude at Ti, are more likely to show lower than average materialism at Ti+1. The TSO shows that individuals with a higher than their usual level of gratitude at Ti are more likely to show a lower than their usual level of materialism at Ti+1. Important implications for materialism research as well as for the Positive Organizational Psychology field are discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.https://www.mdpi.com/1660-4601/18/7/378