Lower Detection Probability of Avian Plasmodium in Blood Compared to Other Tissues.

We tested whether the probability of detecting avian haemosporidia (Plasmodium and Haemoproteus) using molecular techniques differs among blood, liver, heart, and pectoral muscle tissues. We used a paired design, sampling the 4 tissue types in 55 individuals of a wild South American suboscine antbird, the white-shouldered fire-eye (Pyriglena leucoptera). We also identified parasites to cytochrome b lineage. Detection probability was significantly lower in blood compared to the other 3 tissue types combined. Eight of 22 infections were not detected in blood samples; 4-7 infections were not detected in the other individual tissues. The same parasite lineage was recovered from different tissues.

Molecular phylogeny of Threskiornithidae (Aves: Pelecaniformes) based on nuclear and mitochondrial DNA.

The family Threskiornithidae includes 13 genera and 32 species, and it is traditionally divided into 2 subfamilies: Plataleinae and Threskiornithinae. We present a phylogenetic reconstruction to test the monophyly of currently accepted subfamilies, including 15 species from both subfamilies and 10 genera of family Threskiornithidae. Phylogenetic trees were inferred on the basis of the mitochondrial 16S rRNA gene and the nuclear intron 7 of ß-fibrinogen. Threskiornithidae was recovered as a monophyletic group. Plataleinae formed a monophyletic group, but nested within Threskiornithinae, which was thus paraphyletic. Two major phylogenetic groups were identified: the 'endemic New World clade', including genera endemic to the American continent, and the 'widespread clade', comprising the remaining species. These phylogenetic groups diverged about 39-42 million years ago, i.e., before the separation of South America and Antarctica. Our results agree with an initial vicariance due to Gondwana break-up and subsequent colonization of species from the Old World to the New World.

Identifying management units in non-endangered species: the example of the sloth Bradypus variegatus Schinz, 1825

In this study we propose the analysis of genetic diversity of the common three-toed sloth, Bradypus variegatus, in an attempt to understand population structure, identify divergent intraspecific units, and contribute to the knowledge of biodiversity in the neotropical forests. We analyzed a 387 bp segment of the mitochondrial DNA control region in 28 individuals distributed in different localities of both Atlantic and Amazon forests. Our results demonstrated that the genetic diversity of B. variegatus is distributed in six management units, MUs. The observed MUs encompass six phylogenetic lineages and represent respectively north and south regions of Atlantic forest, three regions within the Amazon forest, and a transition region between these two biomes. Considering the fact that these MUs are concordant with phylogroups and endemism areas already described for other vertebrate species, we can say that the study of B. variegatus, a widely distributed and not endangered species, can help to identify areas for conservation biology purposes in neotropical rain forests.

Neste estudo nós realizamos a análise da diversidade genética da preguiça comum, Bradypus variegatus, a fim de compreender os padrões de estrutura populacional, identificar unidades intraespecíficas divergentes e contribuir para o conhecimento da biodiversidade nas florestas da região neotropical. Nós analisamos um segmento de 387 pb da região controle do DNA mitocondrial de 28 indivíduos distribuídos em diferentes localidades da Floresta Amazônica e da Mata Atlântica. Os resultados obtidos demonstram que a diversidade genética da espécie pode ser representada em seis diferentes unidades de manejo (UM). Tais UMs englobam seis linhagens filogenéticas e estão localizadas em diferentes regiões geográficas sendo elas, as porções norte e sul da Mata Atlântica, três regiões dentro da área de Floresta Amazônica e uma área de transição entre os dois domínios de mata. As diferentes unidades intraespecíficas de B. variegatus são concordantes com grupos filogeográficos e áreas de endemismo já observadas para outras espécies de vertebrados. Levando em consideração o fato de que estas UMs concordam com filogrupos e áreas de endemismo previamente descritos para outras espécies de vertebrados, o estudo da preguiça comum, uma espécie amplamente distribuída e considerada não ameaçada de extinção, pode auxiliar na identificação de áreas destinadas à conservação biológica ao longo das florestas úmidas da região neotropical.

Identifying management units in non-endangered species: the example of the sloth Bradypus variegatus Schinz, 1825.

In this study we propose the analysis of genetic diversity of the common three-toed sloth, Bradypus variegatus, in an attempt to understand population structure, identify divergent intraspecific units, and contribute to the knowledge of biodiversity in the neotropical forests. We analyzed a 387 bp segment of the mitochondrial DNA control region in 28 individuals distributed in different localities of both Atlantic and Amazon forests. Our results demonstrated that the genetic diversity of B. variegatus is distributed in six management units, MUs. The observed MUs encompass six phylogenetic lineages and represent respectively north and south regions of Atlantic forest, three regions within the Amazon forest, and a transition region between these two biomes. Considering the fact that these MUs are concordant with phylogroups and endemism areas already described for other vertebrate species, we can say that the study of B. variegatus, a widely distributed and not endangered species, can help to identify areas for conservation biology purposes in neotropical rain forests.

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.

Genetic diversity in different populations of sloths assessed by DNA fingerprinting

In this study we analyzed a population of Bradypus torquatus with individuals originally distributed in different localities of Bahia, and two populations of B. variegatus with individuals from Bahia and Sõo Paulo States. Using the DNA fingerprinting method, we assessed the genetic variability within and between populations. Analysis of the DNA profiles revealed genetic similarity indices ranging from 0.34 ± 0.07 to 0.87 ± 0.04. Similar low levels of genetic variability were found only in isolated mammalian populations or among related individuals. This study presents the first analyses of genetic diversity in sloth populations

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities.

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

Genetic diversity in different populations of sloths assessed by DNA fingerprinting.

In this study we analyzed a population of Bradypus torquatus with individuals originally distributed in different localities of Bahia, and two populations of B. variegatus with individuals from Bahia and São Paulo States. Using the DNA fingerprinting method, we assessed the genetic variability within and between populations. Analysis of the DNA profiles revealed genetic similarity indices ranging from 0.34 +/- 0.07 to 0.87 +/- 0.04. Similar low levels of genetic variability were found only in isolated mammalian populations or among related individuals. This study presents the first analyses of genetic diversity in sloth populations.

DNA fingerprinting in the rare black-fronted piping guan Pipile jacutinga (Cracidae, Aves).

Brazilian Cracidae are threatened by heavy environmental degradation and hunting. The Black-fronted piping-guan (Pipile jacutinga) used to inhabit the Atlantic coastal highland forests. Now it occurs in limited forest areas where it is rarely seen. Interative management, including captive breeding, might be an important action for its survival. We present data on DNA fingerprinting using Jeffreys' human minisatellite probes 33.6 and 33.15. Our results show that this technique is useful for estimating the genetic variability of natural populations and may help to maintain the genetic variability of captive bred individuals of this species. A linkage analysis of the fingerprint profiles in a family with 7 chicks was performed (to estimate the number of independently segregating loci detected in this species) and at least 16 highly polymorphic independent loci were identified for each probe.