To contribute to our understanding of the genome complexity of sugarcane, we undertook a large-scale expressed sequence tag (EST) program. More than 260,000 cDNA clones were partially sequenced from 26 standard cDNA libraries generated from different sugarcane tissues. After the processing of the sequences, 237,954 high-quality ESTs were identified. These ESTs were assembled into 43,141 putative transcripts. Of the assembled sequences, 35.6% presented no matches with existing sequences in public databases. A global analysis of the whole SUCEST data set indicated that 14,409 assembled sequences (33% of the total) contained at least one cDNA clone with a full-length insert. Annotation of the 43,141 assembled sequences associated almost 50% of the putative identified sugarcane genes with protein metabolism, cellular communication/signal transduction, bioenergetics, and stress responses. Inspection of the translated assembled sequences for conserved protein domains revealed 40,821 amino acid sequences with 1415 Pfam domains. Reassembling the consensus sequences of the 43,141 transcripts revealed a 22% redundancy in the first assembling. This indicated that possibly 33,620 unique genes had been identified and indicated that >90% of the sugarcane expressed genes were tagged

In this work we show that the lumen of Aedes aegypti midgut is highly colonized by bacteria that were identified by culture-dependent and culture-independent methods. rDNA sequences obtained were compared with those from GenBank and the main bacterial genera identified were: Serratia, Klebsiella, Asaia, Bacillus, Enterococcus, Enterobacter,Kluyvera and Pantoea. All genera were identified in midgut except Enterobacter that was observed only in eggs. Asaia and Pantoea were also identified in eggs and ovary, respectively. In addition two yeast genera were observed in A. aegypti: Pichia isolated from midgut and Candida identified in midgut and ovary. The genus Serratia was dominant in all isolation assays representing 54.5% of the total of microorganisms. Thirty-nine and 24 bacterial clones were successfully obtained from midguts 24 and 48h after blood feeding (ABF), respectively. The majority of clones obtained were from Serratia sp. (48.7% and 50% for 24 and 48h ABF, respectively). Light microscopy showed that bacteria were located preferentially in the posterior midgut, around the blood meal and associated with peritrophic matrix. Scanning electron microscopy images showed a high number of bacteria in midgut during blood digestion and the peak of bacterial enumeration was reached 48h ABF, stage in which lumen was almost totally occupied by bacteria that were also interacting with epithelial microvilli. Our results show the dynamics of microbial colonization and their distribution in midgut during blood digestion.

Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis.

The evolutionary basis for high species diversity in tropical regions of the world remains unresolved. Much research has focused on the biogeography of speciation in the Amazon Basin, which harbors the greatest diversity of terrestrial life. The leading hypotheses on allopatric diversification of Amazonian taxa are the Pleistocene refugia, marine incursion, and riverine barrier hypotheses. Recent advances in the fields of phylogeography and species-distribution modeling permit a modern re-evaluation of these hypotheses. Our approach combines comparative, molecular phylogeographic analyses using mitochondrial DNA sequence data with paleodistribution modeling of species ranges at the last glacial maximum (LGM) to test these hypotheses for three co-distributed species of leafcutter ants (Atta spp.). The cumulative results of all tests reject every prediction of the riverine barrier hypothesis, but are unable to reject several predictions of the Pleistocene refugia and marine incursion hypotheses. Coalescent dating analyses suggest that population structure formed recently (Pleistocene-Pliocene), but are unable to reject the possibility that Miocene events may be responsible for structuring populations in two of the three species examined. The available data therefore suggest that either marine incursions in the Miocene or climate changes during the Pleistocene—or both—have shaped the population structure of the three species examined. Our results also reconceptualize the traditional Pleistocene refugia hypothesis, and offer a novel framework for future research into the area.

A survey of the filamentous fungi other than the symbiotic one found in association with Atta sexdens rubropilosa colonies was carried out. Different fungal species (27 taxa) were isolated a few days after treating the workers with toxic baits (sulfluramid; Mirex-S), from 40 laboratory and 20 field nests. Syncephalastrum racemosum (54%) and Escovopsis weberi (21%), Trichoderma harzianum (38%) and Fusarium oxysporum (23%) were the prevalent species in laboratory and field nests, respectively. Acremonium kiliense, Acremonium strictum, E. weberi, F. oxysporum, Fusarium solani, Moniliella suaveolens and T. harzianum were found in both nests' groups. We revealed that many filamentous fungi can co-exist in a dormant state inside the nests of these insects and some of them appear to be tightly associated with this environment.

We show for the first time that the ventral diverticulum of the mosquito gut (impermeable sugar storage organ) harbors microorganisms. The gut diverticulum from newly emerged and non-fedAedes aegypti (Diptera: Culicidae, Aedini) is the main urban vector for the human diseases yellow fever and dengue fever (Nasci & Miller 1996). The vector control, mainly by insecticide application and elimination of oviposition sites, has been used as the best solution to decrease the diseases incidence. Explore new strategies for blocking the insect transmitted diseases such as dengue fever is urgent in Tropical countries (Sperança & Capurro 2007). Microorganisms associated with the insect may have an important role for human infectious diseases epidemiology. Once a key role bacterium is discovered, it may be modified in order to affect the pathogen development and, consequently, the disease transmission (Azambuja et al. 2005, Riehle & Jacobs-Lorena 2005.The alimentary canal of the mosquito is composed by the foregut, midgut and hindgut. The foregut is involved primarily with ingestion, conduction and storage of food (Romoser 1996). In the alimentary canal of the mosquito three diverticula arise near the posterior end of the esophagus: two from the dorso-lateral and one from the ventral wall of the gut, all surrounded by a thin impermeable cuticle. The ventral diverticulum (VD), or crop, is large and may extend into the abdomen (Dapples & Lea 1974). Usually all three diverticula are filled with air bubbles and are used as food reservoirs (Thompson 1905, Consoli & Lourenço-de-Oliveira 1994. The sugar meal, such as floral nectar, is stored in the diverticula and passes slowly to the midgut, where it is digested (Thompson 1905).Microorganisms play important and often essential roles in the growth and development of many insect species. Despite the importance of these microbial associations with insects there are relatively few studies that elucidate their components and their roles in the interactions. Insects that rely on nutritionally poor diets tend to possess bacterial endosymbionts. Aphids, for example, which subsist solely on plant sap, harbor Buchnera spp., believed to provide amino acids and vitamins to their hosts (Douglas 1989). Blood is known to be severely deficient in essential B vitamins and some amino acids. Bloodsucking arthropods such as ticks, lice, bedbugs, reduviid bugs, and tsetse flies usually harbor symbiotic microorganisms (Buchner 1965). Symbiotic relationships have already been reported for blood feeding insects and some are very well established, as in the case of Rhodnius prolixus that maintains an association with the actinomycete bacteria Rhodococcus rhodnii (Dasch et al. 1984); and tsetse flies genus Glossina, which harbor three distinct symbiotic microorganisms: Wigglesworthia glossinidia, Sodalis glossinidius (commensal), and the parasitic microbe Wolbachia pipientis (Aksoy et al. 1997, Chen et al. 1999.Many key questions about bacteria within the mosquito's midgut remain largely unanswered, and ob...

The fungus‐growing ants and their fungal cultivars constitute a classic example of a mutualism that has led to complex coevolutionary dynamics spanning c. 55–65 Ma. Of the five agricultural systems practised by fungus‐growing ants, higher‐attine agriculture, of which leaf‐cutter agriculture is a derived subset, remains poorly understood despite its relevance to ecosystem function and human agriculture across the Neotropics and parts of North America. Among the ants practising higher‐attine agriculture, the genus Trachymyrmex Forel, as currently defined, shares most‐recent common ancestors with both the leaf‐cutter ants and the higher‐attine genera Sericomyrmex Mayr and Xerolitor Sosa‐Calvo et al. Although previous molecular‐phylogenetic studies have suggested that Trachymyrmex is a paraphyletic grade, until now insufficient taxon sampling has prevented a full investigation of the evolutionary history of this group and limited the possibility of resolving its taxonomy. Here we describe the results of phylogenetic analyses of 38 Trachymyrmex species, including 27 of the 49 described species and at least 11 new species, using four nuclear markers, as well as phylogenetic analyses of the fungi cultivated by 23 species of Trachymyrmex using two markers. We generated new genetic data for 112 ants (402 new gene sequences) and 95 fungi (153 new gene sequences). Our results corroborate previous findings that Trachymyrmex, as currently defined, is paraphyletic. We propose recognizing two new genera, Mycetomoellerius gen.n. and Paratrachymyrmex gen.n., and restricting the continued use of Trachymyrmex to the clade of nine largely North American species that contains the type species [Trachymyrmex septentrionalis (McCook)] and that is the sister group of the leaf‐cutting ants. Our fungal cultivar phylogeny generally corroborates previously observed broad patterns of ant–fungus association, but it also reveals further violations of those patterns. Higher‐attine fungi are divided into two groups: (i) the single species Leucoagaricus gongylophorus (Möller); and (ii) its sister clade, consisting of multiple species, recently referred to as Leucoagaricus Singer ‘clade B’. Our phylogeny indicates that, although most non‐leaf‐cutting higher‐attine ants typically cultivate species in clade B, some species cultivate L. gongylophorus, whereas still others cultivate fungi typically associated with lower‐attine agriculture. This indicates that the attine agricultural systems, which are currently defined by associations between ants and fungi, are not entirely congruent with ant and fungal phylogenies. They may, however, be correlated with as yet poorly understood biological traits of the ants and/or of their microbiomes.

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