ABSTRACT
The toxicity of pesticides to organisms depends on the total amount of chemical exposure. Toxicity can be minimized if the organism recognizes the pesticide and alters its behavior. Furthermore, the physical barrier of cuticular hydrocarbons can prevent the entrance of the pesticide into the organism. Finally, if the pesticide enters the body, the organism experiences physiological changes favoring detoxification and the maintenance of homeostasis. We analyzed the behavioral and metabolic response of the spider Polybetes pythagoricus at different times of exposure to the organophosphate pesticide chlorpyrifos. First we observed that the individuals are capable of recognizing and avoiding surfaces treated with pesticides based on a behavioral analysis. Subsequently, we characterized cuticular hydrocarbons as a possible barrier against pesticides. Then we observed that the pesticide provoked histological damage, mainly at the level of the midgut diverticula. Finally, we analyzed the activity of several of the spider's enzymes linked to oxidative stress after exposure to chlorpyrifos for different lengths of time (6, 24, and 48 h). We observed that catalase activity was high at the start, whereas the activity of superoxide dismutase and glutathione S-transferase changed significantly at 48 h. Lipid peroxidation became high at 6 h, but decreased at 48 h. In conclusion, although P. pythagoricus can avoid contact with chlorpyrifos, this pesticide causes activation of the antioxidant system when it enters the body. Our results make a significant contribution to the ecotoxicology of spiders. Environ Toxicol Chem 2023;42:1293-1308. © 2023 SETAC.
Subject(s)
Chlorpyrifos , Insecticides , Pesticides , Spiders , Animals , Insecticides/metabolism , Chlorpyrifos/toxicity , Spiders/metabolism , Catalase/metabolism , Pesticides/toxicity , Antioxidants/metabolism , Oxidative StressABSTRACT
Analysis of energy expense during development has achieved special interest through time on account of the crucial role of the consumption of resources required for offspring survival. Spider eggs have a fixed composition as well as some initial energy that is supplied by mothers. These resources are necessary to support the metabolic expense not only through the embryonic period but also during the post-embryonic period, as well as for post emerging activities before spiderlings become self-sustaining. Depletion of these resources would be critical for spiders since it could give rise to prey competition as well as filial cannibalism. Even though spiders represent a megadiverse order, information regarding the metabolic requirements during spiders development is very scarce. In this study, we analyse the changes in protein, lipid and carbohydrate content as well as the variation in lipovitellin reserves and hemocyanin content during Polybetes pythagoricus development. Our results show that lipovitellins and phospholipids represent the major energy source throughout embryonic and post-embryonic development. Lipovitellin apolipoproteins are gradually consumed but are later depleted after dispersion. Phosphatidylethanolamine is mainly consumed during the post-embryonic period, while triacylglycerides are consumed after juveniles' dispersion. Finally, hemocyanin concentration starts to increase in postembryonic stages.
Subject(s)
Spiders , Animals , Cannibalism , Carbohydrates , Embryonic Development , Hemocyanins/chemistry , Hemocyanins/metabolismABSTRACT
The aim of the present study was to evaluate the effects of the neonicotinoid insecticide imidacloprid (commercial formulation) on juveniles of the spider Misumenops maculissparsus (Keyserling, 1891). We first analyzed whether spiders recognized the presence of the insecticide on surfaces and in drinking water (in the form of droplets). Next, we investigated if the insecticide generated histologic, physiologic, and/or biochemical alterations. We observed that spiders do not detect the insecticide on a surface (e.g., paper) or in the form of droplets. After the imidacloprid ingestion by droplet intake, most spiders exhibited a paralysis that reverted after 48 h. Consequently, we observed histopathologic damage (i.e., pigment accumulation, necrosis, and cuticle detachment), and an increased catalase (CAT) activity and total-protein concentration in the individuals treated. The activities of glutathione-S-transferase, glutathione peroxidase, glutathione reductase, and superoxide dismutase, however, did not undergo significant variations. The results obtained emphasize the need to consider different classes of biomarkers, such as CAT and other proteins, to identify and evaluate the histologic, biologic, and biochemical effects of imidacloprid, one of the most widely used insecticides. Environ Toxicol Chem 2022;41:2152-2161. © 2022 SETAC.
Subject(s)
Insecticides , Spiders , Animals , Antioxidants , Glutathione Transferase/metabolism , Insecticides/toxicity , Neonicotinoids/toxicity , Nitro Compounds/toxicity , Spiders/metabolismABSTRACT
Due to the preeminence of reductionist approaches, understanding of plant responses to combined stresses is limited. We speculated that light-quality signals of neighbouring vegetation might increase susceptibility to heat shocks because shade reduces tissue temperature and hence the likeness of heat shocks. In contrast, plants of Arabidopsis thaliana grown under low-red/far-red ratios typical of shade were less damaged by heat stress than plants grown under simulated sunlight. Neighbour signals reduce the activity of phytochrome B (phyB), increasing the abundance of PHYTOCHROME-INTERACTING FACTORS (PIFs). The phyB mutant showed high tolerance to heat stress even under simulated sunlight, and a pif multiple mutant showed low tolerance under simulated shade. phyB and red/far-red ratio had no effects on seedlings acclimated with nonstressful warm temperatures before the heat shock. The phyB mutant showed reduced expression of several fatty acid desaturase (FAD) genes and less proportion of fully unsaturated fatty acids and electrolyte leakage of membranes exposed to heat shocks. Red-light-activated phyB also reduced thermotolerance of dark-grown seedlings but not via changes in FADs expression and membrane stability. We propose that the reduced photosynthetic capacity linked to thermotolerant membranes would be less costly under shade, where the light input limits photosynthesis.
Subject(s)
Arabidopsis/radiation effects , Cell Membrane/radiation effects , Phytochrome B/metabolism , Thermotolerance/radiation effects , Acclimatization , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Fatty Acid Desaturases/metabolism , Fatty Acids, Unsaturated/metabolism , Global Warming , Heat-Shock Response , Phytochrome B/genetics , Seedlings/radiation effects , Thermotolerance/genetics , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolismABSTRACT
Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (Km ) was 1.7 mM with a kcat of 75 s-1. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310-320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.
Subject(s)
Humans , Male , Female , Antibodies , Phospholipids/immunology , Immunoglobulins/analysis , Prothrombin TimeABSTRACT
Se revisan los principales aspectos relacionados con el diagnostico, clasificacion y tratamiento del cancer del pulmon. Infortunadamente, a pesar de los grandes avances obtenidos en el campo de la cirugia, la radioterapia y la quimioterapia, el pronostico de esta enfermedad continua siendo malo. La sobrevida global a 5 anos es menor del 10%. En consecuencia, el exito obtenido en el control de la enfermedad dependera basicamente de su prevencion y diagnostico temprano
Subject(s)
Humans , Male , Female , Carcinoma, Bronchogenic , Lung Neoplasms , Bronchoscopy , Carcinoma, Bronchogenic/analysis , Carcinoma, Bronchogenic/secondary , Lung Neoplasms/analysis , Lung Neoplasms/drug therapy , Lung Neoplasms/secondary , Lung Neoplasms/surgery , Lung Neoplasms/ultrastructure , Spirometry , Tomography, X-Ray ComputedABSTRACT
Con el fin de investigar las caracteristicas clinico-epidemiologicas del SIDA en Colombia, establecimos dos grupos de estudio prospectivos: el primero, un estudio clinico, iniciado en enero , 1984 y el segundo un estudio serepidemiologico iniciado en septiembre, 1985. El grupo 1 estuvo compuesto de 25 portadores asintomaticos y 51 pacientes con SIDA o sus sindromes relacionados (15 con SIDA florido, 9 con CRS y 27 con LPG). El grupo II por 294 homosexuales y bisexuales que deseaban una serologia para VIH y que voluntariamente respondiernon un cuestionario sobre practicas sexuales. El estudio clinico (GrupoI), demostro que la infeccion mas frecuente fue neumonia por P. carinii (20%), seguida de enteritis por Criptosporidium (12%), M. avium intracellularae diseminado, meningitis por C. neoformans y herpes anogenital persistente (8%). Sarcoma de Kaposi se presento en 4 pacientes. Hubo un caso de linfoma primario de cerebro y otro de carcinoma nasofaringeo. El descenso del promedio del recuento total CD4 fue altamente significativo en SIDA florido cuando se comparo con LPG y CRS (p 0.0001 y p. 0.05) respectivamente. Igual sucedio con el promedio de la relacion CD4/CD8 en SIDA florido cuando se comparo con LPG (p.0.003). En el grupo II la tasa de seropositividad para VIH fue 21%. Los que informaron un rol anal pasivo (anal predominante o mixto activo-pasivo) tuvieron una seropositividad del 24%, significativamente mas alta que los anal activos (11%) (p=0.02, RR=2.31). En sujetos que tuvieron relacion anal pasiva con turistas extranjeros el riesgo fue tambien...
Subject(s)
Humans , Male , Female , Prospective Studies , Acquired Immunodeficiency Syndrome/complications , Acquired Immunodeficiency Syndrome/diagnosis , Acquired Immunodeficiency Syndrome/epidemiology , Acquired Immunodeficiency Syndrome/microbiology , Acquired Immunodeficiency Syndrome/blood , Carcinoma , Colombia , Lymphoma , Sarcoma, KaposiABSTRACT
The application of immunological markers in lymphomas, their biological importance and their diagnostic use are described. The advantages of performing these techniques in tissue are emphasized; they make immunopathology a very practical and accesible tool for the study of lymphoproloferative disorders. As more information is acquired, important correlations among the different immunological phenotypes, the morphological findings and the clinical behavior will be uncovered. In the mean time the diagnostic advantages of performing immunopathological studies in lymphosomas not only justify this resource but occasionaly make it mandatory.
Subject(s)
Humans , Lymphoma/classification , Lymphoma/immunology , Lymphoma, Non-Hodgkin/classification , Immunologic TestsABSTRACT
Se informa un nuevo caso de mucormicosis cutanea por Rhizopus arrhizus, observado en una paciente lesionada durante la catastrofe acaecida en Armero, Colombia, en noviembre de 1985. Se revisa la literatura y se plantea una nueva forma de clasificacion de las infecciones necrosantes de la piel y tejidos blandos, dividiendolas en clostridiales, no clostridiales y micoticas para facilitar su diagnostico y tratamiento.
