ABSTRACT
Although bacterial wilt remains a major plant disease throughout South America and the Caribbean, the diversity of prevalent Ralstonia solanacearum populations is largely unknown. The genetic and phenotypic diversity of R. solanacearum strains in French Guiana was assessed using diagnostic polymerase chain reactions and sequence-based (egl and mutS) genotyping on a 239-strain collection sampled on the families Solanaceae and Cucurbitaceae, revealing an unexpectedly high diversity. Strains were distributed within phylotypes I (46.9%), IIA (26.8%), and IIB (26.3%), with one new endoglucanase sequence type (egl ST) found within each group. Phylotype IIB strains consisted mostly (97%) of strains with the emerging ecotype (IIB/sequevar 4NPB). Host range of IIB/4NPB strains from French Guiana matched the original emerging reference strain from Martinique. They were virulent on cucumber; virulent and highly aggressive on tomato, including the resistant reference Hawaii 7996; and only controlled by eggplant SM6 and Surya accessions. The emerging ecotype IIB/4NPB is fully established in French Guiana in both cultivated fields and uncultivated forest, rendering the hypothesis of introduction via ornamental or banana cuttings unlikely. Thus, this ecotype may have originated from the Amazonian region and spread throughout the Caribbean region.
Subject(s)
Cucurbitaceae/microbiology , Genetic Variation , Genome, Bacterial/genetics , Plant Diseases/microbiology , Ralstonia solanacearum/genetics , Solanaceae/microbiology , Bacterial Proteins/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Ecotype , French Guiana , Genotype , Geography , Host Specificity , Molecular Typing , Phenotype , Phylogeny , Polymerase Chain Reaction , Ralstonia solanacearum/classification , Ralstonia solanacearum/isolation & purification , Ralstonia solanacearum/pathogenicity , Sequence Analysis, DNA , VirulenceABSTRACT
Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). We report a novel missense mutation in the PRNP gene (resulting in a G114V mutation in PrP) in members of a Uruguayan family with clinical and histopathologic features of prion disease. Affected individuals were characterized by an early age at onset, initial neuropsychiatric symptoms, late dementia with prominent pyramidal and extrapyramidal symptoms, and long disease duration.
Subject(s)
Amyloid/genetics , Brain/physiopathology , Genetic Predisposition to Disease/genetics , Mutation/genetics , Prion Diseases/genetics , Protein Precursors/genetics , Adolescent , Adult , Age of Onset , Amino Acid Substitution/genetics , Biopsy , Brain/metabolism , Brain/pathology , Chromosome Aberrations , DNA Mutational Analysis , Dementia/genetics , Dementia/pathology , Dementia/physiopathology , Disease Progression , Fatal Outcome , Female , Frontal Lobe/metabolism , Frontal Lobe/pathology , Frontal Lobe/physiopathology , Genetic Testing , Humans , Male , Personality Disorders/genetics , Personality Disorders/pathology , Personality Disorders/physiopathology , Prion Diseases/pathology , Prion Diseases/physiopathology , Prion Proteins , Prions , Pyramidal Tracts/metabolism , Pyramidal Tracts/pathology , Pyramidal Tracts/physiopathology , UruguayABSTRACT
Cultured human peripheral blood mononuclear leucocytes (PBML) were able to synthesize indoleamines, including melatonin, and were also able to convert melatonin taken up from the incubation medium into N-acetyl-5-hydroxytryptamine (NAHT) and 5-hydroxytryptamine (5-HT). These compounds were analysed by h.p.l.c., and melatonin was additionally characterized by two-dimensional t.l.c., mass spectrometry and radioimmunoassay. Only hydroxyindoles were detected by h.p.l.c. in unstimulated PBML culture. Sustained stimulation by melatonin or interferon-gamma (IFN-gamma) increased markedly the basal production of 5-HT. IFN-gamma- or 5-HT-stimulated (but not resting) cells produced NAHT and melatonin. Furthermore, the addition of melatonin to the culture medium strongly enhanced NAHT and 5-HT production without affecting tryptophan hydroxylation, suggesting the possibility of direct or indirect transformation of melatonin into NAHT and 5-HT.