Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera).

Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.

Ethanol fuel improves arthropod capture in pitfall traps and preserves DNA.

We tested the value of ethanol fuel as a killing solution in terms of sampling efficiency (species richness and accumulated abundance) and DNA preservation of Ensifera ground-dwelling specimens. Sampling efficiency was evaluated comparing abundance and species richness of pitfall sampling using 100% ethanol fuel, with two alternative killing solutions. We evaluated the DNA preservation efficiency of the killing solutions and of alternative storage solutions. Ethanol fuel was the most efficient killing solution, and allowed successful DNA preservation. This solution is cheaper than other preserving liquids, and is easily acquired near field study sites since it is available at every fuel station in Brazil and at an increasing number of fuel stations in the U.S. We recommend the use of ethanol fuel as a killing and storage solution, because it is a cheap and efficient alternative for large-scale arthropod sampling, both logistically and for DNA preservation. For open habitat sampling with high day temperatures, we recommend doubling the solution volume to cope with high evaporation, increasing its efficacy over two days.

Does variation in genome sizes reflect adaptive or neutral processes? New clues from Passiflora.

One of the long-standing paradoxes in genomic evolution is the observation that much of the genome is composed of repetitive DNA which has been typically regarded as superfluous to the function of the genome in generating phenotypes. In this work, we used comparative phylogenetic approaches to investigate if the variations in genome sizes (GS) should be considered as adaptive or neutral processes by the comparison between GS and flower diameters (FD) of 50 Passiflora species, more specifically, within its two most species-rich subgenera, Passiflora and Decaloba. For this, we have constructed a phylogenetic tree of these species, estimated GS and FD of them, inferred the tempo and mode of evolution of these traits and their correlations, using both current and phylogenetically independent contrasted values. We found significant correlations among the traits, when considering the complete set of data or only the subgenus Passiflora, whereas no correlations were observed within Decaloba. Herein, we present convincing evidence of adaptive evolution of GS, as well as clues that this pattern is limited by a minimum genome size, which could reduce both the possibilities of changes in GS and the possibility of phenotypic responses to environment changes.

Morphology and morphometry of three Plasmodium juxtanucleare (Apicomplexa: Plasmodiidae) isolates.

In this work, three isolates of Plasmodium juxtanucleare have been analyzed based on morphological, morphometric and parasitic parameters. Each isolate was sampled from naturally infected adult chicken (Gallus gallus) from rural areas of three Brazilian municipalities: Seropédica (22 degrees 48' S; 43 degrees 41' W), in the state of Rio de Janeiro; Cruzeiro (22 degrees 33' S; 44 degrees 57' W), in the state of São Paulo; and Santa Bárbara do Tugúrio (21 degrees 15' S; 43 degrees 27' W), in the state of Minas Gerais. The blood samples taken from each infected chicken were inoculated in three groups of ten young chicken (21 days old). Blood smears of the experimentally infected chicken were sampled every two days until the 69th day in order to evaluate the parasitemia. For the morphological-descriptive and morphometric analyses, we measured 30 individuals from each of the intraerythocytic states, measures of the major (MD) and minor diameters (md), the estimation of morphometric index (Mi=md/MD) and size (T=pab, a=md/2; b=MD/2). The results indicated low and homogeneous parasitemia rates in the three strains, which showed differences among shape and size of the parasitic stadia displayed.

Morphology and morphometry of three Plasmodium juxtanucleare (Apicomplexa: Plasmodiidae) isolates / Morfologia e morfometria de três isolados de Plasmodium juxtanucleare (Apicomplexa: Plasmodiidae)

In this work, three isolates of Plasmodium juxtanucleare have been analyzed based on morphological, morphometric and parasitic parameters. Each isolate was sampled from naturally infected adult chicken (Gallus gallus) from rural areas of three Brazilian municipalities: Seropédica (22º 48' S; 43º 41'W), in the state of Rio de Janeiro; Cruzeiro (22º 33' S; 44º 57'W), in the state of São Paulo; and Santa Bárbara do Tugúrio (21º 15' S; 43º 27' W), in the state of Minas Gerais. The blood samples taken from each infected chicken were inoculated in three groups of ten young chicken (21 days old). Blood smears of the experimentally infected chicken were sampled every two days until the 69th day in order to evaluate the parasitemia. For the morphological-descriptive and morphometric analyses, we measured 30 individuals from each of the intraerythocytic states, measures of the major (MD) and minor diameters (md), the estimation of morphometric index (Mi=md/MD) and size (T=pab, a= md/2; b=MD/2). The results indicated low and homogeneous parasitemia rates in the three strains, which showed differences among shape and size of the parasitic stadia displayed.

Neste trabalho, três isolados de Plasmodium juxtanucleare foram analisados com base na morfologia, morfometria e parâmetros parasitológicos. Cada isolado foi coletado de aves (Gallus gallus) adultas infectadas naturalmente de áreas rurais de três municípios brasileiros: Seropédica (22º 48' S; 43º 41' W), no estado do Rio de Janeiro; Cruzeiro (22º 33' S; 44º 57' W), no estado de São Paulo; e Santa Bárbara do Tugúrio (21º 15' S; 43º 27' W), no estado de Minas Gerais. As amostras de sangue coletadas de cada ave infectada foram inoculadas em três grupos de dez aves (21 dias de idade). Esfregaços sangüíneos das aves infectadas experimentalmente foram realizados de dois em dois dias durante um período de 69 dias para avaliar a parasitemia. Para análises morfofisiológica e morfométrica, foram mensurados 30 indivíduos de cada estágio intraeritrocítico. Foram tomadas as medidas do diâmetro maior (DM) e diâmetro menor (dm), com os quais foi estimado o índice morfométrico (Mi=md/MD) e o tamanho (T=pab, a= md/ 2; b=MD/2). Os resultados indicaram uma parasitemia homogênea entre os três isolados, havendo diferenças apenas nas formas e tamanhos dos estádios parasitários.

A phylogenomic appraisal of the evolutionary relationship of mycoplasmas

Several genomes of mycoplasmas have been sequenced and here we tried to retrieve the evolutionary relationships of nine species using a phylogenomic approach. Several methods were used to build phylogenetic trees based on protein sequence information, gene-order, and gene-content. We also utilized datasets composed of individual and concatenated sets of orthologous proteins, as well as with reduced unreliable alignment regions. Most of our results converge to a single topology, except for the trees built with both the maximum parsimony method and with the gene-order dataset. The gene-content dataset presented trees consistent with most nodes of the convergent tree, but in the gene-order dataset most internal branches were clearly saturated and unreliable. The topological difference between the trees obtained by the diverse methods could not be explained by regions with unreliable alignments or attributed to horizontal gene transfer among the genomes. It is possible that the incongruence between the methods could be associated with their differential sensibility in relation to certain evolutionary factors. Further analysis using other empirical genomic datasets would be necessary in order to better understand the basis of such conflicts.

Testing the trend towards specialization in herbivore-host plant associations using a molecular phylogeny of Tomoplagia (Diptera: Tephritidae).

Herbivorous insects are abundant and diverse and insect-host plant associations tend to be specialized and evolutionarily conserved. Some authors suggested that generalist insect lineages tend to become specialists, with host specialization leading to an evolutionary dead-end for the parasite species. In this paper, we have examined this tendency using a phylogenetic tree of Tomoplagia (Diptera: Tephritidae), a parasite of asteracean plants. We have tested the trend towards specialization in different hierarchical degrees of host specialization. The topology of the tree, the inference of ancestral hosts, and the lack of directional evolution indicated that specialization does not correspond to a phylogenetic dead-end. Although most Tomoplagia species are restricted to a single host genus, specialization does not seem to limit further host range evolution. This work emphasizes the advantages of the use of different levels of specialization and the inclusion of occasional hosts to establish a more detailed scenario for the evolution of this kind of ecological association.