RESUMO
The interaction of antimesometrial decidual cells and collagen fibrils was studied by light microscopy and ultrastructural cytochemistry in fed and acutely fasted mice on days 9-11 of pregnancy. Fibrillar elements in the extracellular space consisted of collagen fibrils and filamentous aggregates (disintegrating collagen fibrils). Intracellular vacuoles exhibited typical collagen immersed in electron-translucent material (clear vacuoles) and faint cross-banded collagen immersed in electron-opaque material (dark vacuoles). Fibrillar elements showed extracellular acid phosphatase activity which was stronger in the region of mature decidua than in predecidual cells region in all animals; it was conspicuous in mature decidua of fasted animals. Intracellular acid phosphatase activity was observed in dark vacuoles and lysosomes, and was absent in clear vacuoles in all cells studied. Since acid phosphatase activity reflects the presence of lysosomal hydrolases in general, the results indicate that breakdown of extracellular collagen occurs by release of lysosomal enzymes by decidual cells and also by internalization of collagen for intracellular degradation in fed and fasted mice. Collagen breakdown may be part of the process of tissue remodeling in mature and predecidual regions, however, in mature decidua, collagen breakdown is enhanced and may therefore contribute to nutrition of the fetus, specially in acutely fasted mice.
Assuntos
Animais , Feminino , Camundongos , Gravidez , Colágeno/metabolismo , Decídua/metabolismo , Decídua/ultraestrutura , Matriz Extracelular/metabolismo , Histocitoquímica , Fosfatase Ácida/metabolismo , Fosfatase Ácida/ultraestrutura , Matriz Extracelular/enzimologia , Jejum , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Microscopia EletrônicaRESUMO
The interaction of antimesometrial decidual cells and collagen fibrils was studied by light microscopy and ultrastructural cytochemistry in fed and acutely fasted mice on days 9-11 of pregnancy. Fibrillar elements in the extracellular space consisted of collagen fibrils and filamentous aggregates (disintegrating collagen fibrils). Intracellular vacuoles exhibited typical collagen immersed in electron-translucent material (clear vacuoles) and faint cross-banded collagen immersed in electron-opaque material (dark vacuoles). Fibrillar elements showed extracellular acid phosphatase activity which was stronger in the region of mature decidua than in predecidual cells region in all animals; it was conspicuous in mature decidua of fasted animals. Intracellular acid phosphatase activity was observed in dark vacuoles and lysosomes, and was absent in clear vacuoles in all cells studied. Since acid phosphatase activity reflects the presence of lysosomal hydrolases in general, the results indicate that breakdown of extracellular collagen occurs by release of lysosomal enzymes by decidual cells and also by internalization of collagen for intracellular degradation in fed and fasted mice. Collagen breakdown may be part of the process of tissue remodeling in mature and predecidual regions, however, in mature decidua, collagen breakdown is enhanced and may therefore contribute to nutrition of the fetus, specially in acutely fasted mice.
Assuntos
Colágeno/metabolismo , Decídua/metabolismo , Decídua/ultraestrutura , Matriz Extracelular/metabolismo , Histocitoquímica , Fosfatase Ácida/metabolismo , Fosfatase Ácida/ultraestrutura , Animais , Matriz Extracelular/enzimologia , Jejum , Feminino , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Camundongos , Microscopia Eletrônica , GravidezRESUMO
Paracoccidioidomycosis is a systemic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. It is the most prevalent systemic mycosis of Latin America and 80% of the reported cases are from Brazil. Because of the great number of neutrophils found in the P. brasiliensis granuloma, studies have been done to evaluate the role of these cells during the development of the infection. Scanning and transmission electron microscopy of thin sections showed that the neutrophils ingest yeast cells through a typical phagocytic process with the formation of pseudopodes. The pseudopodes even disrupt the connection established between the mother and the bud cells. Neutrophils also associate to each other, forming a kind of extracellular vacuole where large yeast cells are encapsulated. Cytochemical studies showed that once P. brasiliensis attaches to the neutrophil surface, it triggers a respiratory burst with release of oxygen-derived products. Attachment also triggers neutrophils degranulation, with release of endogenous peroxidase localized in cytoplasmic granules. Together, these processes lead to killing of both ingested and extracellular P. brasiliensis.
Assuntos
Neutrófilos/microbiologia , Paracoccidioides/patogenicidade , Paracoccidioidomicose/sangue , Fosfatase Ácida/sangue , Fosfatase Ácida/ultraestrutura , FMN Redutase/sangue , FMN Redutase/ultraestrutura , Humanos , Cinética , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Neutrófilos/ultraestrutura , Paracoccidioides/citologia , Paracoccidioides/ultraestrutura , Paracoccidioidomicose/patologiaRESUMO
The insect stage of the protozoan parasite Leishmania mexicana secretes a filamentous acid phosphatase (secreted acid phosphatase, SAP), a polymeric phosphoglycoprotein. The wild-type (wt) SAP filament is a copolymer composed of two related gene products SAP1 and SAP2, which are identical in the enzymatically active NH2-terminal domain and the COOH-terminal domain, but differ in the length of a highly glycosylated Ser/Thr-rich repeat region (32 amino acids and 383 amino acids, respectively) which is located between these domains. When expressed separately, full length SAP1, SAP2, or the NH2-terminal domain alone, are able to assemble into filaments. The Ser/Thr-rich region is the exclusive target for a novel type of O-glycosylation via phosphoserines. By using glycerol spraying/low-angle rotary metal shadowing and labelling with monoclonal antibodies it is demonstrated that the repetitive region adopts an extended conformation forming side arms which project radially from the filament core and terminate with the COOH-terminal domain. The length of the side arms of SAP1 and SAP2 (20 nm and 90 nm, respectively) corresponds to the predicted length of the Ser/Thr-rich repeat region of SAP1 and SAP2. Mass determination by scanning electron microscopy (STEM) shows that one morphologically defined globular particle of the filament core is a polypeptide dimer. We propose a model for the filament core, in which the globular NH2-terminal SAP domains form one strand composed of polypeptide dimers or two tightly associated strands of monomers which may twist into a double helix, similar to actin filaments. The highly O-glycosylated side arms project from the filament core conferring an overall bottle-brush-like appearance. The L. mexicana SAP is compared to SAPs secreted by the closely related species L. amazonensis and L. donovani.
Assuntos
Fosfatase Ácida/ultraestrutura , Glicoproteínas/ultraestrutura , Leishmania mexicana/enzimologia , Fosfoproteínas/ultraestrutura , Fosfatase Ácida/biossíntese , Fosfatase Ácida/genética , Animais , Dimerização , Deleção de Genes , Glicoproteínas/biossíntese , Glicoproteínas/genética , Insetos/parasitologia , Leishmania/enzimologia , Leishmania donovani/enzimologia , Microscopia Eletrônica de Transmissão e Varredura , Modelos Moleculares , Mutagênese , Fosfoproteínas/biossíntese , Fosfoproteínas/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/ultraestruturaRESUMO
El objetivo del presente trabajo fue analizar la presencia de lisosomas en el sinciciotrofoblasto de placentas humanas a término cultivadas y no cultivadas. Se realizó el estudio ultraestructural y ultracitoquímico para fosfatasa ácida mediante dos técnicas que emplean distintos sustratos y análisis morfométricos en 7 placentas humanas normales a término. Dos de ellas se mantuvieron previamente en cultivos de tejido durante 48 h. El estudio reveló la presencia de escasos cuerpos densos lisosomales con localizaciones supranucleares en relación con vacuolas de endocitosis y principalmente en regiones adelgazadas del sinciciotrofoblasto. La población lisosomal representó un 2,8% a 4,0% de la superficie sincicial. De acuerdo a los resultados, se sugiere que los lisosomas de placentas humanas e términos participarían en el intercambio materno fetal
Assuntos
Humanos , Feminino , Gravidez , Lisossomos/ultraestrutura , Trofoblastos/ultraestrutura , Fosfatase Ácida/ultraestrutura , Troca Materno-FetalRESUMO
El objetivo del presente trabajo fue analizar la presencia de lisosomas en el sinciciotrofoblasto de placentas humanas a término cultivadas y no cultivadas. Se realizó el estudio ultraestructural y ultracitoquímico para fosfatasa ácida mediante dos técnicas que emplean distintos sustratos y análisis morfométricos en 7 placentas humanas normales a término. Dos de ellas se mantuvieron previamente en cultivos de tejido durante 48 h. El estudio reveló la presencia de escasos cuerpos densos lisosomales con localizaciones supranucleares en relación con vacuolas de endocitosis y principalmente en regiones adelgazadas del sinciciotrofoblasto. La población lisosomal representó un 2,8% a 4,0% de la superficie sincicial. De acuerdo a los resultados, se sugiere que los lisosomas de placentas humanas e términos participarían en el intercambio materno fetal (AU)