The pathogenesis of five different Newcastle disease virus (NDV) isolates representing all pathotypes was examined in commercial and specific pathogen-free (SPF) turkeys. Experimentally-infected birds were monitored clinically and euthanatized, with subsequent tissue collection, for examination by histopathology, by immunohistochemistry for the presence of NDV nucleoprotein, and by in situ hybr...

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there a...

EspC and Pet are toxins secreted by the diarrheagenic enteropathogenic and enteroaggregative Escherichia coli pathotypes, respectively. Both toxins have a molecular mass around 110 kDa and belong to the same protein family called Serine Protease Autotransporters of the Enterobacteriaceae (SPATE). Furthermore, both toxins act within the cytosol of intoxicated epithelial cells to disrupt the arch...

T h e nor thern root-knot nematode, Meloidogyne hapla Chitwood, 1949, parasitizes a number of impor tant crops in Washington (1). M. hapla is widespread on Concord grapes (Vitis labrusca L.), and heavy infestations have been associated with vines with poor growth. All the same, a greenhouse pathogenicity study with an isolate of M. hapla from alfalfa (Medicago sativum L.) showed that Concord gr...

Part of the Thesis of the first author. Universidade Federal de Viçosa. Viçosa MG. 2004. *Present Address: Laboratório de Microbiologia Agrícola, ICA, Universidade Federal Rural da Amazônia, 66077-530, Belém, PA, Brazil ABSTRACT Genetic and phenotypic structure of Magnaporthe oryzae populations of two upland rice cultivars was determined. Monoconidial isolates were obtained from rice blast aff...

INTRODUCTION The diarrhea associated with gastroenteritis is a major cause of morbidity and mortality worldwide, affecting mainly infants. The characterization of both viral and bacterial agents associated with gastroenteritis can establish policies for surveillance, prevention and treatment of infections. Group A rotaviruses are the major infectious agent associated with dehydration in childre...

The genetic and phenotypic diversity of the Ralstonia solanacearum species complex, which causes bacterial wilt to Solanacae, was assessed in 140 strains sampled from the main vegetable production areas of the Mayotte island. Only phylotype I strains were identified in the five surveyed areas. The strains were distributed into the following 4 sequevars: I-31 (85.7%), I-18 (5.0%), I-15 (5.7%), a...

Escherichia coli (E. coli) is a normal inhabitant of the gastrointestinal tract of vertebrates, including humans. Phylogenetic analysis has shown that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D). Group A and B1 are generally associated with commensals, whereas group B2 is associated with extra-intestinal pathotypes. Most enteropathogenic isolates, however, are assigne...

Transmission electron microscopy (TEM) was used to characterize the colonization patterns of 3 pathogenic Escherichia coli strains: PD58 and PD149 of the AIDA-I/STb/EAST1 pathotype, serogroup O: ND (not determined), and PD31 of the LT/STb/EAST1 pathotype, serogroup O149. These strains were isolated from diseased piglets and caused diarrhea in experimentally inoculated, newborn, colostrum-depriv...