Comparative analyses of the complete genome sequences of Pierce's disease and citrus variegated chlorosis strains of Xylella fastidiosa

Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X.fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X.fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X.fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X.fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis, permitting convergence of functional genomic strategies.18531018102

Comparison of different diagnostic tests in dogs uninfected and naturally infected with visceral leishmaniasis

Uninfected dogs (n = 10) and those naturally infected with leishmaniasis (n = 10) were subjected to several diagnostic tests, namely: hemoculture, polymerase chain reaction (PCR) of hemoculture, indirect immunofluorescence (RIFI), cytological examination of lymph node aspirate, culture of lymph node aspirate and PCR of lymph node aspirate. RIFI - followed by PCR of lymph node aspirate culture - presented more positive results in infected dogs than in uninfected ones. In infected animals, RIFI was more effective than PCR of lymph node aspirate culture. There was no statistical difference in positivity between RIFI and hemoculture; lymph node aspirate culture/cytological examination of lymph node aspirate and PCR of hemoculture; and between PCR of lymph node aspirate culture and PCR of hemoculture. All infected and uninfected animals had positive and negative results in at least one test. In conclusion, the association of several tests improves the efficacy of canine visceral leishmaniasis diagnosis