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1.
Biol. Res ; 50: 5, 2017. tab, graf
Article in English | LILACS | ID: biblio-838972

ABSTRACT

BACKGROUND: Salmonella pathogenicity island (SPI)-13 is conserved in many serovars of S. enterica, including S. Enteritidis, S. Typhimurium and S. Gallinarum. However, it is absent in typhoid serovars such as S. Typhi and Paratyphi A, which carry SPI-8 at the same genomic location. Because the interaction with macrophages is a critical step in Salmonella pathogenicity, in this study we investigated the role played by SPI-13 and SPI-8 in the interaction of S. Enteritidis and S. Typhi with cultured murine (RAW264.7) and human (THP-1) macrophages. RESULTS: Our results showed that SPI-13 was required for internalization of S. Enteritidis in murine but not human macrophages. On the other hand, SPI-8 was not required for the interaction of S. Typhi with human or murine macrophages. Of note, the presence of an intact copy of SPI-13 in a S. Typhi mutant carrying a deletion of SPI-8 did not improve its ability to be internalized by, or survive in human or murine macrophages. CONCLUSIONS: Altogether, our results point out to different roles for SPI-13 and SPI-8 during Salmonella infection. While SPI-13 contributes to the interaction of S. Enteritidis with murine macrophages, SPI-8 is not required in the interaction of S. Typhi with murine or human macrophages. We hypothesized that typhoid serovars have lost SPI-13 and maintained SPI-8 to improve their fitness during another phase of human infection.


Subject(s)
Humans , Animals , Mice , Salmonella enteritidis/genetics , Salmonella Infections/microbiology , Salmonella typhi/genetics , Genomic Islands/physiology , Macrophages/microbiology , Species Specificity , Cell Survival , Cells, Cultured , Polymerase Chain Reaction , Analysis of Variance , Genome, Bacterial , Bacterial Physiological Phenomena , Genomic Islands/genetics , Microbial Interactions/genetics , Serogroup , RAW 264.7 Cells , Muridae
2.
Biol. Res ; 45(1): 21-26, 2012. ilus, tab
Article in English | LILACS | ID: lil-626743

ABSTRACT

Shigella flexneri causes bacillary dysentery in humans. Essential to the establishment of the disease is the invasion of the colonic epithelial cells. Here we investigated the role of the lipopolysaccharide (LPS) O antigen in the ability of S. flexneri to adhere to and invade polarized Caco-2 cells. The S. flexneri 2a O antigen has two preferred chain lengths: a short O antigen (S-OAg) regulated by the WzzB protein and a very long O antigen (VL-OAg) regulated by Wzz pHS2. Mutants with defined deletions of the genes required for O-antigen assembly and polymerization were constructed and assayed for their abilities to adhere to and enter cultured epithelial cells. The results show that both VL- and S-OAg are required for invasion through the basolateral cell membrane. In contrast, the absence of O antigen does not impair adhesion. Purified LPS does not act as a competitor for the invasion of Caco-2 cells by the wild-type strain, suggesting that LPS is not directly involved in the internalization process by epithelial cells.


Subject(s)
Humans , Bacterial Adhesion/physiology , Bacterial Proteins/analysis , Dysentery, Bacillary/microbiology , O Antigens/chemistry , Shigella flexneri/pathogenicity , Dysentery, Bacillary/immunology , O Antigens/metabolism , Polymerization , Shigella flexneri/immunology
3.
Rev. latinoam. microbiol ; 29(2): 183-7, abr.-jun. 1987. tab
Article in English | LILACS | ID: lil-105179

ABSTRACT

Se hidrolizó coseta agotada de remolacha utilizando celulasas provenientes de una especie nativa de Trichoderma hazianum. Se obtuvo un 52% de conversión de los carbohidratos presentes en la coseta a azúcares reductores. La fermentación de los azúcares liberados a etanol mediante un proceso de hidrólisis y fermentación combinadas dio como resultado un 66% de conversión del component celulósico de la coseta en eatanol, con un rendimiento de 4,4 g/L de etanol. Al realizar la hidrólisis y fermentación en forma simultánea los rendimientos fueron similares, lográndose un 62% de conversión del componente celulósico de la coseta en etanol. Estos resultados se comparan con los obtenidos utilizando celulosa microcristalina como sustrato


Subject(s)
Ethanol , Fermentation , Hydrolysis , Saccharomyces cerevisiae/metabolism , Trichoderma/metabolism , Cellulose/metabolism
4.
Bol. Hosp. San Juan de Dios ; 32(4): 264-8, jul.-ago. 1985.
Article in Spanish | LILACS | ID: lil-30442

ABSTRACT

Se presentan los resultados de la aplicación de un método de detección de tumores "in vivo" mediante anticuerpos marcados con radioisótopos, en un paciente portador de un tumor colorrectal. Para ello se utilizan anticuerpos anti-CEA-I131. Se describe la técnica del procedimiento y se efectúa una revisión de la literatura pertinente. Se señala que el caso comunicado es el primero en el que se aplica la radioinmunodetección en nuestro medio


Subject(s)
Adult , Humans , Male , Carcinoembryonic Antigen , Colonic Neoplasms , Rectal Neoplasms
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