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31.
Simone V. Generoso Mirelle Viana Rosana Santos Flaviano S. Martins José A. N. Machado Rosa M. E. Arantes Jacques R. Nicoli Maria I. T. D. Correia Valbert N. Cardoso 《Archives of microbiology》2010,192(6):477-484
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. 相似文献
32.
Diva M. A. Dusi Elizangela R. Alves Michiel T. M. Willemse Rosana Falcão Cacilda B. do Valle Vera T. C. Carneiro 《Sexual plant reproduction》2010,23(3):187-197
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. 相似文献
33.
Crespo R de Bravo MG Colinas PA Bravo RD 《Bioorganic & medicinal chemistry letters》2010,20(22):6469-6471
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. 相似文献
34.
Molecular View by Fourier Transform Infrared Spectroscopy of the Relationship between Lactocin 705 and Membranes: Speculations on Antimicrobial Mechanism
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Patricia Castellano Graciela Vignolo Ricardo Norberto Farías Jos Luis Arrondo Rosana Chehín 《Applied microbiology》2007,73(2):415-420
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. 相似文献
35.
Costa MA Elesgaray R Caniffi C Fellet A Arranz C 《Biochemical and biophysical research communications》2007,359(1):180-186
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. 相似文献
36.
Batista WL Barros TF Goldman GH Morais FV Puccia R 《Fungal genetics and biology : FG & B》2007,44(5):347-356
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. 相似文献
37.
38.
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. 相似文献
39.
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. 相似文献
40.
Ana Claudia Guerra Araujo Rosana Falcão Vera Tavares de Campos Carneiro 《Sexual plant reproduction》2007,20(3):109-121
Gametophytic organization, fertilization and reproductive success are described for the fertile diploid Brachiaria brizantha accession BRA-002747 which is being raised for use in Brachiaria breeding programs, as well as to understand and control of apomixis in this genus. The current paper reports on reproductive
biology and analysis of seed set in field experiments during three consecutive years. Unsuccessful seed production in this
plant is believed to correlate with early inbreeding depression, based on the reproductive features analyzed. Caryopsis development
was observed using differential interference contrast microscopy with seed set determined by the number of self- and open-pollinated
pistils that fully developed into viable seeds. Developing and mature female and male gametophytes were observed in the context
of flower phenology, morphology and anthesis patterns. Pollen viability was determined by acetocarmine staining and by observation
of germination in vivo, which was also used to observe pollen tube/pistil interaction. Although normal development was observed
in floral structures, anthesis and gametophytes, seed set was low, with 2 and 6% in self- and open-pollination, respectively,
producing seed. Variations observed in the female organs, such as the presence of a hermaphrodite flower in 50% of the inferior
floscules and the presence of multiple embryo sacs of the Polygonum type within the same ovule in 15% of the pistils, are
not related to low fertility. The majority of pollen grains are viable, in spite of the reduced number of pollen tubes within
the style and ovary carpel, and a developing caryopsis was observed in 70% of self-pollinated pistils, indicating successful
double fertilization from 2 days after anthesis (DAA). Nevertheless, abortion gradually increased from 2 until 7 DAA and remains
elevated until 12 DAA, when caryopsis maturity is achieved. These data confirm low seed set in this accession and indicate
that low fertility is not a consequence of abnormalities, either in the floral or gamete structures, or pollen tube rejection,
but most likely a consequence of inbreeding depression. 相似文献