Polytene chromosomes as indicators of phylogeny in several species groups of Drosophila.

BackgroundPolytene chromosome banding patterns have long been used by Drosophila evolutionists to infer degree of relatedness among taxa. Recently, nucleotide sequences have preempted this traditional method. We place the classical Drosophila evolutionary biology tools of polytene chromosome inversion analysis in a phylogenetic context and assess their utility in comparison to nucleotide sequences.ResultsA simultaneous analysis framework was used to examine the congruence of the chromosomal inversion data with more recent DNA sequence data in four Drosophila species groups - the melanogaster, virilis, repleta, and picture wing. Inversions and nucleotides were highly congruent with one another based on incongruence length difference and partitioned Bremer support values. Inversion phylogenies were less resolved because of fewer numbers of characters. Partitioned Bremer supports, corrected for the number of characters in each matrix, were higher for inversion matrices.ConclusionsPolytene chromosome data are highly congruent with DNA sequence data and, when placed in a simultaneous analysis framework, are shown to be more information rich than nucleotide data

Investigation of the spread bovine tuberculosis in Southern Brazil by Whole-genome sequencing.

Mycobacterium bovis is the causal agent of bovine tuberculosis, one of the most important diseases currently facing the cattle industry worldwide. Tracing the source of M. bovis infections that result from movement of livestock is an important tool to understand the epidemiology of bovine tuberculosis (bTB) and defining control/eradication strategies. Whole genome sequencing (WGS) provides a higher resolution than other established typing methods and greatly improves the definition of the regional localization of M. bovis types. Cultures of M. bovis were isolated from 58 bovine granulomatous tissue using conventional methods (Stonebrink medium) from eight dairy farms of the State of Rio Grande do Sul, Southern Brazil. The isolates were sequenced using both llumina technologies NextSeq 500 System and HiSeqX System

False-negative reactions to the comparative intradermal tuberculin test for bovine tuberculosis.

According to the Brazilian National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT), the routine tests for the diagnosis of bovine tuberculosis in the country are the simple intradermal tuberculin test (SITT) of the Ministry of Agriculture, Livestock and Food Supply (MAPA), the caudal fold test and the comparative intradermal tuberculin test (CITT). The latter is also used as a confirmatory test. A group of 53 animals from three dairy herds in a focal area for bovine tuberculosis, that were submitted to depopulation in the state of Rio Grande do Sul, were submitted to the CITT. Tissues were cultured and the resulting colonies were confirmed by PCR and DNA sequencing. Among the 53 animals analyzed using the CITT, 32 (60.4%) were negative, 14 (26.4%) were positive and seven (13.2%) results were inconclusive. The CITT detected 11 of the 39 animals with culture-confirmed M. bovis infection as positive. Among the total of 14 uninfected animals based on cultures, the CBT detected eight as negative. Thus, the CITT demonstrated sensitivity of 28.2% and specificity of 57.1% for the population sampled. A total of 24/32 (75.0%) of the animals with negative CITT results were culture positive (confirmed by PCR) and were considered false negatives based on the CITT. The maintenance of these false-negative animals in herds has serious implications for the control of the disease, since they can be a source of infection. The addition of complementary tests could help identify such animals and increase the odds of diagnostic success.Título em português: Reações falso-negativas ao teste cervical comparativo para tuberculose bovina

Tuberculose bovina em cervídeos.

A tuberculose bovina (bTB) é uma enfermidade infectocontagiosa, causada por Mycobacterium bovis, que acomete animais domésticos, silvestres e o homem. Em animais silvestres mantidos em cativeiro, a bTB representa risco aos tratadores de animais e aos visitantes de zoológicos, e há também a possibilidade de disseminação da infecção para animais domésticos e pela venda de animais silvestres infectados. Cervídeos das espécies sambar (Cervus unicolor), nobre (Cervus elaphus) e dama (Dama dama) de um parque safári, do Rio Grande do Sul, apresentaram quadro clínico de bTB (dispneia e perda de peso). Alguns animais foram a óbito, sendo detectadas lesões sugestivas de tuberculose (LST), confirmadas por histopatológica. Com o impedimento de comercialização de animais, realizou-se eutanásia de 281 cervídeos com autorização do IBAMA. Foram coletados linfonodos retrofaríngeos, submandibulares e vísceras de 21 animais, que foram cultivados em meio Stonebrink por até 90 dias. Após extração de DNA das colônias, realizou-se PCR para alvos flanqueando a região de diferenciação 4 (RD4). Das 21 amostras, 14 (61,9%) apresentaram LST, com aspecto granulomatoso, coloração esbranquiçada, e consistência caseosa ou calcificada e sete (38,1%), não apresentaram lesões. No cultivo das 14 amostras com LST, 13 (92,8%) apresentaram crescimento bacteriano compatível com M. bovis. No cultivo das sete amostras sem LST, seis (92,8%) apresentaram colônias compatíveis com M. bovis. A PCR convencional detectou como positivos 19 cultivos bacteriológicos sugestivos de M. bovis, confirmando o surto de bTB nos cervídeos. Lesões também foram detectadas em seis lhamas, um camelo, uma anta e um antílope, as quais foram confirmadas por histopatologia. Este fato sugere que houve transmissão entre espécies, muito embora não tenha sido possível realizar isolamento nestes casos. Estudos de genotipagem por sequenciamento genômico total estão sendo realizados com os isolados de M. bovis dos cervídeos, o que permitirá comparações filogenéticas com outros isolados já sequenciados no estado.bitstream/item/213635/1/Tuberculose-bovina-em-cervideos.pd

ELISA using a recombinant chimera of ESAT-6/MPB70/MPB83 for Mycobacterium bovis diagnosis in naturally infected cattle.

Bovine tuberculosis (bTB) control programs generally rely on intradermal tuberculin tests for the antemortem diagnosis of Mycobacterium bovis infection in cattle, but these tests detect only a portion of the infected animals. The aim of the present study was to evaluate the diagnostic coverage of a combination of the bTB antemortem techniques known as the comparative intradermal tuberculin test (CITT) and an ELISA based on a recombinant chimera of ESAT-6/MPB70/MPB83 as the antigen in cattle. The results were compared to postmortem findings based on M. bovis culturing and PCR. Paired comparisons of all data (n=92) demonstrated that ELISA and LST results compared to the culturing results did not present significant differences (P=0.27 on McNemar?s test and P=0.12 on Fisher?s exact test, respectively). Using culturing as the gold standard, the sensitivity and specificity of ELISA were 79.5% (95% CI: 64.5?89.2%) and 75.5% (95% CI: 62.4?85.1%), respectively, whereas LST demonstrated 100% sensitivity (95% CI: 91.03? 100%) and 92.5% specificity (95% CI: 82.1?97.0%). The ELISA results did not reveal significant differences in relation to the LST results (P>0.99 on Fisher?s exact test). Using the latter as the gold standard, the sensitivity and specificity of ELISA were 79.1% (95% CI: 64.8?88.6%) and 79.6% (95% CI: 66.4?88.5%), respectively. The use of ELISA with the recombinant chimera of ESAT-6/MPB70/ MPB83 as the antigen complements the diagnostic coverage provided by CITT and increases the removal of infected animals from herds

Matrix Assisted Laser Desorption Ionization-Time-of-Flight mass spectrometry identification of Mycobacterium bovis in Bovinae.

In this study, Matrix Assisted Laser Desorption Ionization-Time-of-Flight (MALDITOF) mass spectrometry was used to identify Mycobacterium bovis from cattle and buffalo tissue isolates from the North and South regions of Brazil, grown in solid medium and previously identified by Polymerase Chain Reaction (PCR) based on Region of Difference 4 (RD4), sequencing and spoligotyping. For this purpose, the protein extraction protocol and the mass spectra reference database were optimized for the identification of 80 clinical isolates of mycobacteria. As a result of this optimization, it was possible to identify and differentiate M. bovis from other members of the Mycobacterium tuberculosis complex with 100% specificity, 90.91% sensitivity and 91.25% reliability. MALDI-TOF MS methodology described herein provides successful identification of M. bovis within bovine/bubaline clinical samples, demonstrating its usefulness for bovine tuberculosis diagnosis in the future

Sexual selection on song and cuticular hydrocarbons in two distinct populations of Drosophila montana

Sexual selection has the potential to contribute to population divergence and speciation. Most studies of sexual selection in Drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (CHCs), which can act as contact pheromones. We have examined the relationship between both signal types and reproductive success using F1–3 offspring of wild- collected flies, raised in the lab. We used two populations of the Holarctic species Drosophila montana that represent different phylogeographic clades that have been separate for ca. 0.5 million years (MY), and differ to some extent in both traits. Here, we characterize the nature and identify the targets of sexual selection on song, CHCs, and both traits combined within the populations. Three measures of courtship outcome were used as fitness proxies. They were the probability of mating, mating latency, and the production of rejection song by females, and showed patterns of association with different traits that included both linear and quadratic selection. Courtship song predicted courtship outcome better than CHCs and the signal modalities acted in an additive rather than synergistic manner. Selection was generally consistent in direction and strength between the two populations and favored males that sang more vigorously. Sexual selection differed in the extent, strength, and nature on some of the traits between populations. However, the differences in the directionality of selection detected were not a good predictor of population differences. In addition, a character previously shown to be important for species recognition, interpulse interval, was found to be under sexual selection. Our results highlight the complexity of understanding the relationship between within-population sexual selection and population differences. Sexual selection alone cannot predict differences between populations.Publisher PDFPeer reviewe