Skull diversity and evolution in miniaturized amphibians, genus Brachycephalus (Anura: Brachycephalidae).

Miniaturized amphibians of the genus Brachycephalus are phenotypically diverse. The species of Brachycephalus have bufoniform or leptodactyliform Baupläne and any of three skeletal states: nonhyperossified, hyperossified without dorsal shield, and hyperossified with dorsal shield. We integrate high-resolution microcomputed tomography, geometric morphometrics, and an estimate of molecular phylogenetic relationships to investigate skull diversity in shape and size-shape space in selected species of Brachycephalus. Skull diversity amongst species of Brachycephalus can be partitioned into shape and size-shape space according to the four conditions of skeletal states-Baupläne, namely, nonhyperossified leptodactyliform, nonhyperossified bufoniform, hyperossified bufoniform without dorsal shield, and hyperossified bufoniform with dorsal shield. Skull diversity in shape and size-shape space in nonhyperossified leptodactyliform species of Brachycephalus is markedly larger, when compared to skull diversity in species of the three other conditions of skeletal states-Baupläne. Variation in skull shape scales with size across Brachycephalus and, therefore, can be explained by allometry. Skull diversity, Baupläne, and skeletal states covary to a large extent with monophyletic lineages of Brachycephalus, as revealed by a mitochondrial DNA species tree. Nonhyperossified bufoniform species and hyperossified bufoniform species with or without dorsal shield are monophyletic lineages, as inferred from a mitochondrial DNA species tree. Nonhyperossified leptodactyliform species of Brachycephalus do not share, however, a most recent common ancestor. The nonhyperossified leptodactyliform species of Brachycephalus, due to their marked skull diversity and lack of monophyly, emerge as evolutionarily complex. Therefore, further sampling of the nonhyperossified leptodactyliform condition of skeletal states-Baupläne will be necessary to further understand the evolutionary history of Brachycephalus.

Os anfíbios miniaturizados do gênero Brachycephalus são fenotipicamente diversos. As espécies de Brachycephalus têm o plano corporal bufoniforme ou leptodactyliforme e três estados esqueléticos: não-hiperossificado, hiperossificado sem placa dorsal e hiperossificado com placa dorsal. Neste trabalho nós integramos tomografia micro-computadorizada de alta resolução, morfometria geométrica e uma estimativa de relações filogenéticas moleculares para investigar diversidade craniana nos espaços de forma e tamanho-forma em determinadas espécies de Brachycephalus. A diversidade craniana entre espécies de Brachycephalus pode ser dividida no espaço de forma e tamanho-forma segundo as quatro condições de plano corporal-esqueleto, a saber, leptodactiliforme não-hiperossificado, bufoniforme não-hiperossificado, bufoniforme hiperossificado sem placa dorsal e bufoniforme hiperossificado com placa dorsal. A diversidade craniana nos espaços de forma e tamanho-forma nas espécies de Brachycephalus leptodactiliformes não-hiperossificadas é pronunciadamente maior quando comparada àquela das espécies nas outras trcs condições de plano corporal-esqueleto. A variação na forma craniana aumenta com o tamanho craniano em Brachycephalus e, portanto, pode ser explicada por alometria. Diversidade craniana, plano corporal e estados esqueléticos covariam consideravelmente com as linhagens monofiléticas de Brachycephalus, como estimado pela filogenia mitocondrial. As espécies de Brachycephalus leptodactiliformes não-hiperossificadas e bufoniformes hiperossificadas com ou sem placa dorsal são linhagens monofiléticas, como estimado pela filogenia mitocondrial. As espécies leptodactiliformes não-hiperossificadas não compartilham, todavia, um ancestral comum mais recente. As espécies de Brachycephalus leptodactiliformes não-hiperossificadas devido a sua pronunciada diversidade e não-monofilia emergem claramente como entidades evolutivamente complexas. Por conseguinte, a amostragem adicional de populações leptodactiliformes não-hiperossificadas será necessária para uma melhor compreensão da história evolutiva do gênero Brachycephalus.

Identification of oxidoreductases from the petroleum Bacillus safensis strain.

A gram-positive bacterium, denominated CFA-06, was isolated from Brazilian petroleum in the Campos Basin and is responsible for the degradation of aromatic compounds and petroleum aromatic fractions. The CFA-06 strain was identified as Bacillus safensis using the 16S rRNA and gyrase B sequence. Enzymatic assays revealed the presence of two oxidoreductases: a catalase and a new oxidoreductase. The oxidoreductases were enzymatically digested and analyzed via ESI-LTQ-Orbitrap mass spectrometry. The mass data revealed a novel oxidoreductase (named BsPMO) containing 224 amino acids and 89% homology with a hypothetic protein from B. safensis (CFA-06) and a catalase (named BsCat) with 491 amino acids and 60% similarity with the catalase from Bacillus pumilus (SAFR-032). The new protein BsPMO contains iron atom(s) and shows catalytic activity toward a monooxygenase fluorogenic probe in the presence of cofactors (NADH, NADPH and NAD). This study enhances our knowledge of the biodegradation process of petroleum by B. safensis.

Karyotype variability in tropical maize sister inbred lines and hybrids compared with KYS standard line.

Maize karyotype variability has been extensively investigated. The identification of maize somatic and pachytene chromosomes has improved with the development of fluorescence in situ hybridization (FISH) using tandemly repeated DNA sequences as probes. We identified the somatic chromosomes of sister inbred lines that were derived from a tropical flint maize population (Jac Duro [JD]), and hybrids between them, using FISH probes for the 180-bp knob repeat, centromeric satellite (CentC), centromeric satellite 4 (Cent4), subtelomeric clone 4-12-1, 5S ribosomal DNA and nucleolus organizing region DNA sequences. The observations were integrated with data based on C-banded mitotic metaphases and conventional analysis of pachytene chromosomes. Heterochromatic knobs visible at pachynema were coincident with C-bands and 180-bp FISH signals on somatic chromosomes, and most of them were large. Variation in the presence of some knobs was observed among lines. Small 180-bp knob signals were invariant on the short arms of chromosomes 1, 6, and 9. The subtelomeric 4-12-1 signal was also invariant and useful for identifying some chromosomes. The centromere location of chromosomes 2 and 4 differed from previous reports on standard maize lines. Somatic chromosomes of a JD line and the commonly used KYS line were compared by FISH in a hybrid of these lines. The pairing behavior of chromosomes 2 and 4 at pachytene stage in this hybrid was investigated using FISH with chromosome-specific probes. The homologues were fully synapsed, including the 5S rDNA and CentC sites on chromosome 2, and Cent4 and subtelomeric 4-12-1 sites on chromosome 4. This suggests that homologous chromosomes could pair through differential degrees of chromatin packaging in homologous arms differing in size. The results contribute to current knowledge of maize global diversity and also raise questions concerning the meiotic pairing of homologous chromosomes possibly differing in their amounts of repetitive DNA.

Genome Sequence of Bacillus safensis CFA06, Isolated from Biodegraded Petroleum in Brazil.

Bacillus safensis is a microorganism recognized for its biotechnological and industrial potential due to its interesting enzymatic portfolio. Here, as a means of gathering information about the importance of this species in oil biodegradation, we report a draft genome sequence of a strain isolated from petroleum.

Transcriptome profile of Trichoderma harzianum IOC-3844 induced by sugarcane bagasse.

Profiling the transcriptome that underlies biomass degradation by the fungus Trichoderma harzianum allows the identification of gene sequences with potential application in enzymatic hydrolysis processing. In the present study, the transcriptome of T. harzianum IOC-3844 was analyzed using RNA-seq technology. The sequencing generated 14.7 Gbp for downstream analyses. De novo assembly resulted in 32,396 contigs, which were submitted for identification and classified according to their identities. This analysis allowed us to define a principal set of T. harzianum genes that are involved in the degradation of cellulose and hemicellulose and the accessory genes that are involved in the depolymerization of biomass. An additional analysis of expression levels identified a set of carbohydrate-active enzymes that are upregulated under different conditions. The present study provides valuable information for future studies on biomass degradation and contributes to a better understanding of the role of the genes that are involved in this process.

Evaluating genetic relationships between tropical maize inbred lines by means of AFLP profiling.

Diversity among tropical maize inbred lines that compose breeding programs, is not well known. The lack of this information has made the arrangement of heterotic groups to be used for breeding purposes difficult. Methods of molecular analysis have been used as efficient alternatives for evaluating genetic diversity, aiming at heterotic group arrangement and acquisition of new hybrids. In this study, AFLP (amplified fragment length polymorphism) was used to investigate the genetic relationships among 96 tropical maize inbred lines from two different origins. The polymorphism level among the genotypes and the possibility of their allocation in heterotic groups were evaluated. Besides, correlations among genetic diversity and flowering time were analyzed. Nine primer combinations were used to obtain AFLP markers, producing 638 bands, 569 of which were polymorphic. Genetic similarities (GS), determined by Jaccard's similarity coefficient, varied from 0.345 to 0.891, with an average of 0.543. The dendrogram based on the GS and on the UPGMA cluster method did not separate the inbred lines in well-defined groups. Aiming at separating the lines into more accurate groups, Tocher's optimization procedure was carried out, 17 groups being identified. Association between flowering time and germplasm pools was detected. AFLP showed itself to be a robust assay, revealing a great power of detection of genetic variability in the tropical germplasm, and also demonstrated to be very useful for guiding breeding programs.