Brazilian Cerrado Folivore and Florivore Caterpillars: How Different are They?

Because of the large differences between flower buds and leaves as food resources we predict that florivore caterpillars compared with folivores would present: (1) higher degree of dietary specificity; (2) higher abundance; and (3) lower species richness. Based on emerged adults from caterpillars collected on leaves and inflorescences our results showed that the florivore fauna was strongly dominated by a few species with higher abundance and dietary specificity than the folivore fauna.     

Folivore caterpillars on Roupala montana Aubl. (Proteaceae) in cerrado sensu stricto

Richness of lepidopteran species in the cerrado is high. The confirmation of this richness is based on adult records but knowledge of larvae-host plants interactions is still incipient. The main purpose of this work was to identify folivorous caterpillar species on Roupala montana Aubl. in areas of a Brazilian cerrado sensu stricto, their dietary range, and the relative age of the consumed leaves richness. Three data sets, collected from 1991 to 2004 were used in this study. All caterpillars found on the host plants in the field were collected and reared in the laboratory. Sixty-two lepidopteran species from 22 families were recorded; they were found feeding on new (8%) and mature (92%) leaves of R. montana. Cerconota sciaphilina (Zeller) (Elachistidae), two unidentified Gracillariidae species and, one species of Gelechiidae fed only on new leaves. These species showed a short life cycle, which was very syncronized with the host plant foliar phenology. Among the species feeding on mature leaves, 36 were considered polyphagous and, these showed a large variation in the use of the food resource. Twenty-six species were found only on R. montana, 58% were very rare, a character that difficults the analysis of their dietary range. The monophagous species on R. montana were: Chlamydastisplatyspora (Meyrick) (Elachistidae), Stenoma cathosiota Meyrick (Elachistidae), Idalus prop. sublineata (Rothschild) (Arctiidae), and Eomichla sp. (Oecophoridae).     

Cardiolipin in hydrogenosomes: evidence of symbiotic origin

Hydrogenosomes are found in organisms that lack typical mitochondria. Cardiolipin is a phospholipid located exclusively in bacterial membranes and the inner membrane of mitochondria. Here we show, by cell fractionation, thin-layer chromatography, high-pressure liquid chromatography, and matrix-assisted laser desorption ionization-time of flight mass spectrometry that hydrogenosomes of Tritrichomonas foetus, a cattle vaginal parasite, contain cardiolipin, which is strong evidence for its endosymbiotic origin.     

Genomic selection in soybean: accuracy and time gain in relation to phenotypic selection

Genomic selection (GS) can potentially accelerate genetic improvement of soybean [Glycine max L. (Merrill)] by reducing the time to complete breeding cycles. The objectives of this study were to (1) explore the accuracy of GS in soybean, (2) evaluate the contribution of intrapopulational structure to the accuracy of GS, and (3) compare the efficiencies of phenotypic selection and GS in soybean. For this, phenotypic and genotypic data were collected from 324 soybean genotypes (243 recombinant inbred lines and 81 cultivars) and GS was performed for five yield related traits. BayesB methodology with a 10-fold cross-validation was used to compute accuracies. The GS accuracies were evaluated for grain yield, plant height, insertion of first pod, days to maturity, and 1000-grain weight at eight locations. We found that GS can reduce the time required to complete a selection cycle in soybean, which can lead to increased production of this commercially important crop. Furthermore, genotypic accuracy was similar regardless of population structure correction.     

Extracellular cell wall β(1,3)glucan is required to couple septation to actomyosin ring contraction

Cytokinesis has been extensively studied in different models, but the role of the extracellular cell wall is less understood. Here we studied this process in fission yeast. The essential protein Bgs4 synthesizes the main cell wall β(1,3)glucan. We show that Bgs4-derived β(1,3)glucan is required for correct and stable actomyosin ring positioning in the cell middle, before the start of septum formation and anchorage to the cell wall. Consequently, β(1,3)glucan loss generated ring sliding, oblique positioned rings and septa, misdirected septum synthesis indicative of relaxed rings, and uncoupling between a fast ring and membrane ingression and slow septum synthesis, suggesting that cytokinesis can progress with defective septum pushing and/or ring pulling forces. Moreover, Bgs4-derived β(1,3)glucan is essential for secondary septum formation and correct primary septum completion. Therefore, our results show that extracellular β(1,3)glucan is required for cytokinesis to connect the cell wall with the plasma membrane and for contractile ring function, as proposed for the equivalent extracellular matrix in animal cells.     

Diversity and antibiotic resistance of Acinetobacter spp. in water from the source to the tap

Acinetobacter spp. are ubiquitous bacteria in the environment. Acinetobacter spp. isolated from a municipal drinking water treatment plant and from connected tap water were identified to the species level on the basis of rpoB gene partial sequence analysis. Intraspecies variation was assessed based on the analysis of partial sequences of housekeeping genes (rpoB, gyrB, and recA). Antibiotic resistance was characterized using the disk diffusion method and isolates were classified as wild or non-wild type (non-WT), according to the observed phenotype. The strains of Acinetobacter spp. were related to 11 different validly published species, although three groups of isolates, presenting low rpoB sequence similarities with previously described species, may represent new species. Most of the isolates were related to the species A. johnsonii and A. lwoffii. These two groups, as well as others related to the species A. parvus and A. tjernbergiae, were detected in the water treatment plant and in tap water. Other strains, related to the species A. pittii and A. beijerinckii, were isolated only from tap water. Most of the isolates (80 %) demonstrated wild type (WT) to all of the 12 antibiotics tested. Non-WT for tetracycline, meropenem, and ceftazidime, among others, were observed in water treatment plant or in tap water samples. Although, in general, this study suggests a low prevalence of acquired antibiotic resistance in water Acinetobacter spp., the potential of some species to acquire and disseminate resistance via drinking water is suggested.     

Culture-dependent and culture-independent diversity surveys target different bacteria: a case study in a freshwater sample

Compared with culture-independent approaches, traditionally used culture-dependent methods have a limited capacity to characterize water microbiota. Nevertheless, for almost a century the latter have been optimized to detect and quantify relevant bacteria. A pertinent question is if culture-independent diversity surveys give merely an extended perspective of the bacterial diversity or if, even with a higher coverage, focus on a different set of organisms. We compared the diversity and phylogeny of bacteria in a freshwater sample recovered by currently used culture-dependent and culture-independent methods (DGGE and 454 pyrosequencing). The culture-dependent diversity survey presented lower coverage than the other methods. However, it allowed bacterial identifications to the species level, in contrast with the other procedures that rarely produced identifications below the order. Although the predominant bacterial phyla detected by both approaches were the same (Proteobacteria, Actinobacteria, Bacteroidetes), sequence similarity analysis showed that, in general, different operational taxonomical units were targeted by each method. The observation that culture-dependent and independent approaches target different organisms has implications for the use of the latter for studies in which taxonomic identification has a predictive value. In comparison to DGGE, 454 pyrosequencing method had a higher capacity to explore the bacterial richness and to detect cultured organisms, being also less laborious.