Light and confocal microscopic observations of adult Schistosoma mansoni from mice fed on a high-fat diet

The morphological aspects of Schistosoma mansoni adult worms recovered from albino mice fed on a cholesterol-rich diet compared to mice fed on a standard chow were investigated. After feeding on their respective diets for over a period of 5 months, mice were subcutaneously infected with c. 50 S. mansoni cercariae/mouse. Blood samples were obtained 1 day prior to experimental infections and 63 days later, when mice were euthanized by jugular section (hypovolaemic shock). Total cholesterol (TC) levels were determined. Recovered worms were stained with hydrochloric carmine, and preserved as whole-mounts for examination by bright-field and laser confocal microscopy. The infected mice fed on high-fat chow showed higher levels of serum lipoproteins than the infected mice fed on standard chow, except for very-low-density lipoprotein cholesterol (VLDL-c) and triglycerides (TG). In this experiment, worms from mice fed on a high-fat chow showed a greater percentage of morphological differentiation regarding supernumerary testes, seminal vesicle, and seminal receptacle. In mice of this group, the rate of oocyte laying in the ovary was much higher than in control females. The present results suggest that cholesterol could be actively involved in the modulation of cell signalling and reproduction, because the lobes contained fully developed oocytes in variable amounts, different from control males. The data presented here are the first to report the role of a cholesterol-rich diet affecting the development of S. mansoni worms.     

Identification of a novel potential antigen for early-phase serodiagnosis of leptospirosis

This study examined four genes encoding for predicted membrane proteins selected from the genome sequences of Leptospira interrogans. Genes were cloned and the proteins expressed in E. coli. Immunoblotting analysis of the recombinants with sera from early and convalescent phases of a leptospirosis patient showed that two proteins, namely Lp29 and Lp49, were reactive with serum from both phases of the illness. These data were further confirmed in enzyme-linked immunosorbent assay using sera from both phases of seventeen confirmed leptospirosis specimens, suggesting that these proteins are presented to the host immune system during infection. In the early phase, anti-Lp29 IgM was detected in all sera when microscopic agglutination tests (MAT), the reference method for diagnosis of leptospirosis, were negative. The gene encoding Lp49 is conserved among five tested leptospiral pathogenic serovars, while Lp29 is present in serovars that are predominant in urban settings. These recombinant antigens might be valuable for serodiagnosis of both phases of leptospirosis.     

Reduction of heavy metal contents in liquid effluents by vermicomposts and the use of the metal-enriched vermicomposts in lettuce cultivation

The removal of Cu, Ni and Zn from electroplating effluents by adsorption in cattle manure vermicompost has been discussed. A glass column 38 cm long and 7 cm i.d. was loaded with cattle manure vermicompost and effluents were passed through it. The metal concentrations were measured in the elutant. The experiments on adding effluent aliquots into the columns were continued until the metal concentrations in the elutant reached the maximum values established for effluent discharges in water courses by the Brazilian quality criteria, i.e., Cu=1.0 mg L(-1), Ni=2.0 mg L(-1), and Zn=5.0 mg L(-1). The amount of Cu retention by the vermicompost was determined at the natural effluent pH (2.0). The Zn and Ni retentions were evaluated at the natural effluent pH (6.9 and 7.4, respectively) as well pH 2.0. Vermicompost residues obtained from this process were used for lettuce cultivation. The vermicompost was found to be efficient in removing metals from the electroplating wastes, as well as in the increase of its pH values. Metal retention values were close to 100%. The Cu concentrations in lettuce leaves from the treatment with vermicompost enriched with this metal were below the range of critical toxicity level to plants, i.e., from 20 to 100 mg L(-1). However, the estimated Cu concentrations in the roots from the treatment with vermicompost enriched with Cu were much larger than that of the treatment with the natural vermicompost, reaching 246.3 mg L(-1). The Ni and Zn concentrations in lettuce leaves from the treatments, with vermicomposts enriched with the respective metals, were above the range of critical toxicity levels to plants, i.e., from 10 to 50 mg kg(-1) and from 15 to 30 mg kg(-1), respectively. However, no symptom of toxicity was found visually. Larger accumulations of Cu, Ni and Zn were found in the lettuce leaves than in the roots after the treatments with the uncontaminated vermicompost. A greater absorption of Cu and Ni by roots was found in treatments with vermicompost enriched with these elements, whereas Zn was found preferentially in the leaves. The statistical analysis was done by analyses of variance and regression.     

Structural analysis of Canavalia maritima and Canavalia gladiata lectins complexed with different dimannosides: new insights into the understanding of the structure-biological activity relationship in legume lectins

Plant lectins, especially those purified from species of the Leguminosae family, represent the best studied group of carbohydrate-binding proteins. The legume lectins from Diocleinae subtribe are highly similar proteins that present significant differences in the potency/efficacy of their biological activities. The structural studies of the interactions between lectins and sugars may clarify the origin of the distinct biological activities observed in this high similar class of proteins. In this way, this work presents a crystallographic study of the ConM and CGL (agglutinins from Canavalia maritima and Canavalia gladiata, respectively) in the following complexes: ConM/CGL:Man(alpha1-2)Man(alpha1-O)Me, ConM/CGL:Man(alpha1-3)Man(alpha1-O)Me and ConM/CGL:Man(alpha1-4)Man(alpha1-O)Me, which crystallized in different conditions and space group from the native proteins. The structures were solved by molecular replacement, presenting satisfactory values for R(factor) and R(free). Comparisons between ConM, CGL and ConA (Canavalia ensiformis lectin) binding mode with the dimannosides in subject, presented different interactions patterns, which may account for a structural explanation of the distincts biological properties observed in the lectins of Diocleinae subtribe.     

Signal processes and ROS production in glucose transport regulation by thrombopoietin and granulocyte macrophage-colony stimulation factor in a human leukaemic cell line

In M07e cells, a human megakaryocytic leukaemia line, reactive oxygen species (ROS) are generated in response to cytokines acting as intracellular messengers to modulate glucose transport. The aim of this work was to study the signal cascade involved in the acute glucose transport activation in cells exposed to growth factors, such as granulocyte macrophage-colony stimulation factor (GM-CSF) and thrombopoietin (TPO), to better understand some aspects of the aberrant proliferation in leukaemia. Results confirm ROS involvement in modulation of glucose transport in this cell line. Furthermore, GM-CSF and TPO produced changes in Glut1 phosphorylation and specific inhibitors employed to identify protein kinases involved in Glut activation by these cytokines proved that Akt, PLCγ, Syk and the Src family take part in signal transduction leading to Glut1 activation.     

Interaction of Bacillus thuringiensis svar. israelensis Cry toxins with binding sites from Aedes aegypti (Diptera: Culicidae) larvae midgut

This work shows in vitro processing of Bacillus thuringiensis svar. isralensis Cry toxins and the capacity of the active fragments to bind the midgut microvilli of Aedes aegypti larvae. Processing of Cry11Aa, Cry4Aa and Cry4Ba yielded double fragments of 38-30, 45-20 and 45-18 kDa, respectively. Competition assays showed that all active (125)I-Cry toxins are able to specifically bind to brush border membrane fractions and they might share a common class of binding sites. The values of IC(50) suggested that toxins do not display high affinity for the receptors from brush border membrane fractions, while dissociation assays showed that binding was irreversible, indicating the insertion of toxins in the cell membrane.     

Use of artificial substrata by introduced and cryptogenic marine species in Paranaguá Bay, southern Brazil

Ports are important locations for the introduction of marine species, while marinas and pontoons often serve as secondary habitats for these species. In a marina near Paranaguá Port, a major international port in southern Brazil, the encrusting community was studied to (i) identify possibly introduced species, and (ii) examine the use of artificial substrata by these species. Samples (20 x 20 cm) were taken from fibreglass floats (boardwalks and boat hulls) and concrete columns. A total of 85 species were found of which 50 were classified into three categories: four introduced, 33 cryptogenic and 13 native. The introduced species were the hydrozoan Garveia franciscana (on floats, boats and submerged concrete), the polychaete Polydora cornuta (more abundant on floats and submerged concrete) and the barnacles Amphibalanus reticulatus (equally abundant on the three substrata) and Striatobalanus amaryllis (only on floats and submerged concrete). Organisms were most abundant on floating boardwalks, while species richness and composition were similar to that on boat hulls (32 and 37, respectively), which are an important vector for intraregional transport. All substrata supported at least three of the four introduced, and many of the cryptogenic species. The proportion of introduced to the total number of species was greater than observed in other ports. This demonstrates that the introduction potential is great in Paranaguá Bay, especially considering that this study was restricted to one site and sampled only hard substrata. None of the introduced species has yet been identified as invasive, but all are generalists with respect to substratum, indicating their invasive potential. The ability to colonise stable concrete walls shows that they could also colonise the natural granite rocky substrata in the bay, and the ability to colonise floating surfaces indicate their capability of spreading in the region on the hulls of recreational boats.     

Quantification of global transcription patterns in prokaryotes using spotted microarrays

We describe an analysis, applicable to any spotted microarray dataset produced using genomic DNA as a reference, that quantifies prokaryotic levels of mRNA on a genome-wide scale. Applying this to Mycobacterium tuberculosis, we validate the technique, show a correlation between level of expression and biological importance, define the complement of invariant genes and analyze absolute levels of expression by functional class to develop ways of understanding an organism's biology without comparison to another growth condition.     

An annotated catalogue of salivary gland transcripts in the adult female mosquito, Ædes ægypti*

Background

The number of completely sequenced plastid genomes available is growing rapidly. This array of sequences presents new opportunities to perform comParative analyses. In comParative studies, it is often useful to compare across wide phylogenetic spans and, within angiosperms, to include representatives from basally diverging lineages such as the genomes reported here: Nuphar advena (from a basal-most lineage) and Ranunculus macranthus (a basal eudicot). We report these two new plastid genome sequences and make comparisons (within angiosperms, seed plants, or all photosynthetic lineages) to evaluate features such as the status of ycf15 and ycf68 as protein coding genes, the distribution of simple sequence repeats (SSRs) and longer dispersed repeats (SDR), and patterns of nucleotide composition.

Results

The Nuphar [GenBank:NC_008788] and Ranunculus [GenBank:NC_008796] plastid genomes share characteristics of gene content and organization with many other chloroplast genomes. Like other plastid genomes, these genomes are A+T-rich, except for rRNA and tRNA genes. Detailed comparisons of Nuphar with Nymphaea, another Nymphaeaceae, show that more than two-thirds of these genomes exhibit at least 95% sequence identity and that most SSRs are shared. In broader comparisons, SSRs vary among genomes in s of abundance and length and most contain repeat motifs based on A and T nucleotides.

Conclusion

SSR and SDR abundance varies by genome and, for SSRs, is proportional to genome size. Long SDRs are rare in the genomes assessed. SSRs occur less frequently than predicted and, although the majority of the repeat motifs do include A and T nucleotides, the A+T bias in SSRs is less than that predicted from the underlying genomic nucleotide composition. In codon usage third positions show an A+T bias, however variation in codon usage does not correlate with differences in A+T-richness. Thus, although plastome nucleotide composition shows "A+T richness", an A+T bias is not apparent upon more in-depth analysis, at least in these aspects. The pattern of evolution in the sequences identified as ycf15 and ycf68 is not consistent with them being protein-coding genes. In fact, these regions show no evidence of sequence conservation beyond what is normal for non-coding regions of the IR.