ocas enfermedades infecciosas del sistema nervioso central (SNC) portan tan pobre pronóstico y causan en el médico tal sensación de pesimismo e impotencia como las producidas por las amebas de vida libre. Descubiertas como causa de infección del SNC en humanos desde 1965, las amebas de vida libre están asociadas a dos entidades muy diferentes en sus manifestaciones clínicas y hallazgos anátomo-...

mAbs specific for calmodulin were used to examine the distribution of calmodulin in vegetative Dictyostelium cells. Indirect immunofluorescence indicated that calmodulin was greatly enriched at the periphery of phase lucent vacuoles. The presence of these vacuoles in newly germinated (non-feeding) as well as growing cells, and the response of the vacuoles to changes in the osmotic environment, ...

A clone coding for the F-actin cross-linking protein ct-actinin was obtained by screening a genomic library of Dictyostelium discoideum DNA in ~,gtll with monoclonal antibodies specific for Dictyostelium ¢t-actinin. The 1.2-kilobase (kb) genomic clone was confirmed as containing part of the ¢t-actinin gene by comparing its nudeotide sequencev cith the amino acid sequence of tryptic peptides fro...

Transmembrane signal transduction was investigated in four Dictyostelium discoideum mutants that belong to the fgd A complementation group. The results show the following. (a) Cell surface cAMP receptors are present in fgd A mutants, but cAMP does not induce any of the intracellular responses, including the activation of adenylate or guanylate cyclase and chemotaxis. (b) cAMP induces down-regul...

Gill disease of fry and fingerlings associated with extensive mortality in rainbow trout freshwater farms in Denmark have been observed on an increasing number of occasions in the latest years. Clinical symptoms of hyperventilation indicate respiratory distress. Gross-pathological observations of gills show pale nodules and patches on gill filaments. Histological and scanning electron microscop...

This case is reported with the intention of highlighting the presentation of primary intestinal amoebic disease in Heckel discus Symphysodon discus. The morphology of the parasites and the pathological changes seen using light microscopy were essential. In fresh samples of intestinal content we discovered numerous amoeba-like cells. The trophozoite measures 18.6 x 10.2 mm while the cyst is 11-2...

The objective of this study was to determine whether the permeability characteristics of the nuclear envelope vary during different phases of cellular activity. Both passive diffusion and signal-mediated transport across the envelope were analyzed during the HeLa cell cycle, and also in dividing, confluent (growth-arrested), and differentiated 3T3-LI cultures. Colloidal gold stabilized with BSA...

The objective of this study was to determine whether the permeability characteristics of the nuclear envelope vary during different phases of cellular activity. Both passive diffusion and signal-mediated transport across the envelope were analyzed during the HeLa cell cycle, and also in dividing, confluent (growth-arrested), and differentiated 3T3-LI cultures. Colloidal gold stabilized with BSA...

Ecological science addresses the relations between living things and their environments, and the study of human ecology the particular case of humans. However, there is an opposing tradition built into the foundations of modern science which separates living things and particularly humans, from their environments. Beginning in modern times with Descartes' radical separation of psychology and ph...

The objective of this study was to determine whether the permeability characteristics of the nuclear envelope vary during different phases of cellular activity. Both passive diffusion and signal-mediated transport across the envelope were analyzed during the HeLa cell cycle, and also in dividing, confluent (growth-arrested), and differentiated 3T3-LI cultures. Colloidal gold stabilized with BSA...