Saccharomyces cerevisiae strain UFMG 905 protects against bacterial translocation, preserves gut barrier integrity and stimulates the immune system in a murine intestinal obstruction model

Probiotic is a preparation containing microorganisms that confers beneficial effect to the host. This work assessed whether oral treatment with viable or heat-killed yeast Saccharomyces cerevisiae strain UFMG 905 prevents bacterial translocation (BT), intestinal barrier integrity, and stimulates the immunity, in a murine intestinal obstruction (IO) model. Four groups of mice were used: mice undergoing only laparotomy (CTL), undergoing intestinal obstruction (IO) and undergoing intestinal obstruction after previous treatment with viable or heat-killed yeast. BT, determined as uptake of ^99mTc-E. coli in blood, mesenteric lymph nodes, liver, spleen and lungs, was significantly higher in IO group than in CTL group. Treatments with both yeasts reduced BT in blood and all organs investigated. The treatment with both yeasts also reduced intestinal permeability as determined by blood uptake of ^99mTc-DTPA. Immunological data demonstrated that both treatments were able to significantly increase IL-10 levels, but only viable yeast had the same effect on sIgA levels. Intestinal lesions were more severe in IO group when compared to CTL and yeasts groups. Concluding, both viable and heat-killed cells of yeast prevent BT, probably by immunomodulation and by maintaining gut barrier integrity. Only the stimulation of IgA production seems to depend on the yeast viability.     

Toward in vitro fertilization in Brachiaria spp.

Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants.     

In vitro antitumor activity of N-glycosyl sulfonamides

A series of α-D-hex-2-enopyranosyl sulfonamides was evaluated for their antiproliferative activity against human hepatocellular liver carcinoma (HepG2) and human lung adenocarcinoma (A549) cell lines. The most potent compound (2,4,6-tri-O-acetyl-3-deoxy-α-D-erythro-hex-2-enopyranosyl ethanesulfonamide) showed antiproliferative properties in the micromolar range. The SARs of these sulfonamidoglycoside which includes the influence of carbohydrate rings and sulfonamide class are described.     

Molecular View by Fourier Transform Infrared Spectroscopy of the Relationship between Lactocin 705 and Membranes: Speculations on Antimicrobial Mechanism

Lactocin 705 is a bacteriocin whose activity depends upon the complementation of two peptides, termed Lac705α and Lac705β. Neither Lac705α nor Lac705β displayed bacteriocin activity by itself when the growth of sensitive cells was monitored. To obtain molecular insights into the lactocin 705 mechanism of action, Fourier transform infrared spectroscopy was used to investigate the interactions of each peptide (Lac705α and Lac705β) with dipalmitoylphosphatidylcholine liposomal membranes. Both peptides show the ability to interact with the zwitterionic membrane but at different bilayer levels. While Lac705α interacts with the interfacial region inducing dehydration, Lac705β peptide interacts with only the hydrophobic core. This paper presents the first experimental evidence that supports the hypothesis that Lac705α and Lac705β peptides could form a transmembrane oligomer. From the obtained results, a mechanism of action of lactocin 705 on membrane systems is proposed. The component Lac705α could induce the dehydration of the bilayer interfacial region, and the Lac705β peptide could insert in the hydrophobic region of the membrane where the peptide has adequate conditions to achieve the oligomerization.     

Role of cardiovascular nitric oxide system in C-type natriuretic peptide effects

The aims were to evaluate the role of cardiovascular nitric oxide (NO)-system in C-type natriuretic peptide (CNP) actions and to investigate receptor types and signaling pathways involved in this interaction. Wistar rats were infused with saline or CNP. Mean arterial pressure (MAP) and nitrites and nitrates (NOx) excretion were determined. NO synthase (NOS) activity and NOS expression (Western blot) were analyzed in atria, ventricle and aorta. CNP decreased MAP and increased NOx excretion. CNP estimulated NOS activity, inducing no changes on cardiac and vascular endothelial NOS expression. NOS activity induced by CNP was abolished by suramin and calmidazoliumand but it is not modified by anantin. CNP would interact with NPR-C receptor coupled via G proteins leading to the activation Ca(2+)-calmodulin dependent endothelial NOS, increasing NO production which would induce the reduction in cardiac myocyte contractility and ANP synthesis and secretion in right atria and the relaxation of vascular smooth muscle.     

Identification of transcription elements in the 5' intergenic region shared by LON and MDJ1 heat shock genes from the human pathogen Paracoccidioides brasiliensis. Evaluation of gene expression

The MDJ1/LON locus is conserved among pathogenic dimorphic fungi. We have mapped using DNase I footprinting and mobility shift assays three putative heat shock elements and one AP-1 binding domain (ARE) in the 5' intergenic region shared by PbMDJ1and PbLON (ML) from Paracoccidioides brasiliensis. The region bearing an ARE-like towards PbLON also has an opposite skn-1-like element. We studied genetically and pathogenically distinct isolates Pb18 and Pb3, where ML is polymorphic and the number of elements detected was higher. The functionality of the elements was suggested by the stimulatory response of both genes to heat shock and oxidative stress. Co-regulation occurred upon heat shock from 36 to 42 degrees C and, only in Pb3, also during mycelium to yeast transformation (26-36 degrees C). In Pb18, PbMDJ1 seemed to be preferentially expressed in yeast. Our study might help understand regulation of genes involved in fungal adaptation to the host.     

Effect of organic solvents on the activity and stability of an extracellular protease secreted by the haloalkaliphilic archaeon <Emphasis Type="Italic">Natrialba magadii</Emphasis>

The effect of various organic solvents on the activity and stability of an extracellular protease produced by the haloalkaliphilic archaeon Natrialba magadii was tested. This protease was active and stable in aqueous-organic solvent mixtures containing 1.5 M NaCl and glycerol, dimethylsulfoxide (DMSO), N,N-dimethyl formamide, propylenglycol, and dioxane. Among the solvents tested, DMSO, propylenglycol, and glycerol were effective in preserving enzyme stability in suboptimal NaCl concentrations. The stabilizing effect of DMSO on this haloalkaliphilic protease was more efficient at pH 8 than at pH 10, suggesting that DMSO may not substitute for salt to allow halophilic proteins to withstand the effect of high pH values. These results show that Nab. magadii extracellular protease is a solvent tolerant enzyme and suggest a potential application of this haloalkaliphilic protease in aqueous-organic solvent biocatalysis.     

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.