Increased aortic stiffness assessed by pulse wave velocity in apolipoprotein E-deficient mice

Atherosclerosis develops and progresses spontaneously in apolipoprotein E-knockout (apoE-KO) mice. A direct consequence of atherosclerosis is an increase in vascular stiffness. Pulse wave velocity (PWV) has been used to assess the stiffness of large vessels and was found to be increased in patients with atherosclerosis. In the present study, aortic stiffness was assessed by PWV in 4- and 13-mo-old apoE-KO mice and age-matched controls (C57BL/6J). In 13-mo-old apoE-KO mice with extensive atherosclerotic lesions in the aorta (61 +/- 4%), PWV increased significantly (3.8 +/- 0.2 m/s) compared with controls (2.9 +/- 0.2 m/s). Endothelial nitric oxide (EDNO)-mediated vasorelaxation in response to ACh was markedly diminished in the aortic rings isolated from 13-mo-old apoE-KO mice compared with age-matched controls. In contrast, in 4-mo-old apoE-KO mice with only moderate atherosclerotic lesions in the aorta (23 +/- 5%), there were no significant changes in PWV and EDNO-mediated relaxation compared with controls. Blood pressure was not different among the four groups of mice. There were no significant differences in endothelium-independent vascular responses to sodium nitroprusside among different groups investigated. Histological evaluation revealed focal fragmentation of the elastic laminae in the aortic walls of 13-mo-old apoE-KO mice. These results demonstrate for the first time that aortic stiffness determined by PWV increases in 13-mo-old apoE-KO mice. Endothelial dysfunction and elastic destruction in vascular wall caused by atherosclerosis may have contributed.     

Characterization of a Rab11 homologue in Trypanosoma cruzi

Vesicle trafficking between organelles occurs through fusion of donor and specific acceptor membranes. This process is highly regulated and ensures proper direction in sorting and packaging of a number of molecules in eukaryotic cells. Monomeric GTPases of the Rab family play a pivotal role in the control of membrane fusion and vesicle traffic. In this paper, we characterize a Trypanosoma cruzi Rab 11 homologue (TcRab11) that shares at, the amino acid level, 40% similarity with human rab11, Arabdopsis thaliana rab11 and yeast rab11 homologue genes. Western blot analysis, using a polyclonal rabbit antiserum raised against a synthetic peptide derived from the COOH-terminus of predicted the TcRab11 protein, reacted to a 26kDa protein. In immunofluorescence assays, TcRab 11, was shown to be expressed in epimastigote and amastigote forms, but it was absent in trypomastigotes. Interestingly, the TcRab11 product seems to be located at the reservosome complex, a site of active endocytosis and vesicle fusion present only in the epimastigote stage. Therefore, TcRab11 may represent the first molecular marker of this peculiar organelle.     

Changes in cytoskeletal organization in polyoma middle T antigen-transformed fibroblasts: involvement of protein phosphatase 2A and src tyrosine kinases

The major transforming activity of polyomavirus, middle T antigen, targets several cellular regulatory effectors including protein phosphatase 2A and src tyrosine kinases. Although transformed cells exhibit profound morphological changes, little is known about how middle T antigen-induced changes in the cellular regulatory environment specifically affect the cytoskeleton. We have investigated these changes in 10T(1/2) mouse fibroblasts transformed with polyoma middle T antigen. Immunofluorescence microscopy revealed that expression of middle T antigen (Pym T cells) depleted the stable (acetylated) microtubule array and increased the sensitivity of dynamic (tyrosinated) microtubules to nocodazole-induced disassembly. These effects were associated with a modest but statistically significant (P相似文献   

Enhancement of growth and toxin production of Clostridium argentinense by co-culture with Pseudomonas mendocina

The growth and toxin production of Clostridium argentinense in co-culture with Pseudomonas mendocina was examined in a micro-fermenter without aeration characterizing the association in terms of several growth parameters. The biomass obtained in co-cultures was 4.4 times higher than that in C. argentinense monocultures with total consumption of the carbon source. The pH and Eh attained in co-cultures at later stages of cultivation were suitable for toxin production by C. argentinense. In comparison with C. argentinense monocultures the production of toxin was 17.5 times higher with a specific toxicity of 0.56 LD50 per g of co-culture biomass.     

A limonoid from Trichilia estipulata

The limonoid 21,24,25,26,27-pentanor-15,22-oxo-7alpha,23-dihydroxy-apotirucalla(eupha)-1-en-3-one was isolated from the dichloromethane extract of the stem bark of Trichilia estipulata. Its structure was established by spectroscopic methods (UV, EIMS, 1H and 13C NMR, HMQC and HMBC).     

Purification and characterisation of vanadium haloperoxidases from the brown alga Pelvetia canaliculata

Two enzymes characterised as iodoperoxidases (PcI and PcII), with vanadium-dependent activity, have been purified from the brown alga Pelvetia canaliculata (L.) Decne et Thur. (Fucaceae, Phaeophyceae), collected in the Northern Portuguese coast, at Viana do Castelo. The relative molecular masses were 166 kDa for PcI and 416 kDa for PcII, as determined by gel filtration. SDS-PAGE shows that PcI has just one band corresponding to a subunit of 66 kDa, while PcII shows four bands (66, 72, 157 and 280 kDa). The following kinetic parameters have been determined from a steady-state analysis of the oxidation of iodide by H2O2: PcI, pHopt = 6.0, KM(I-) = 2.1 mM, KM(H2O2) = 110 microM, Ki(I-) = 127 mM; and PcII, pHopt = 6.5, KM(I-) = 2.4 mM, KM(H2O2) = 20 microM and Ki(I-) = 69 mM. These iodoperoxidases are thermostable, as also observed for vanadium bromo- and chloroperoxidases.     

Bi- and tetraflavonoids from Aristolochia ridicula

From stems of Aristolochia ridicula, two biflavones, four unusual chalcone-flavone dimers and one tetraflavonoid were isolated. The structures of the seven compounds were elucidated by spectroscopic methods.     

Ontogenetic events in androgenesis of Brazilian barley genotypes

This paper describes a simple procedure for obtention of barley (Hordeum vulgare L.) doubled haploid plants from Brazilian hybrid genotypes. Anatomical and histological examinations showed the reversion of barley pollen to an sporophytic mode of development. A sequence of mitosis led to the formation of multicellular pollen grains. Regeneration of plants occurred either by direct embryogenesis or callus formation followed by differentiation through direct embryogenesis or organogenesis. Plants were formed in the same medium used for induction dispensing an additional regeneration step. This procedure makes doubled haploid production simpler and faster. Plantlets were transferred to another medium for rooting and after that planted in pots with vermiculite and nutrient solution.     

Worker life tables, survivorship, and longevity in colonies of Bombus (Fervidobombus) atratus (Hymenoptera: Apidae)

Survivorship curves and longevity of workers were studied in two queenright and two queenless colonies of Bombus (Fervidobombus) atratus. Survivorship curves for workers of all colonies were, in general, convex, indicating an increasing mortality rate with increasing age. The mean longevity for the workers from queenright colonies, 24.3 days and 17.6 days, was not significantly different from that in queenless colonies, 21.2 days and 20.2 days. In all colonies workers started foraging activities when aged 0-5 days, and the potential forager rates rose progressively with increasing age. Mortality rates within each age interval were significantly correlated with the foraging worker rates in all colonies. Only in two of the colonies (one queenright and one queenless) longevity was significantly correlated with worker size. The duration of brood development period seems to be one of the most important factors influencing adult worker longevity in bumble bee species.     

Characterization of Biomphalaria orbignyi, Biomphalaria peregrina and Biomphalaria oligoza by polymerase chain reaction and restriction enzyme digestion of the internal transcribed spacer region of the RNA ribosomal gene

The correct identification of Biomphalaria oligoza, B. orbignyi and B. peregrina species is difficult due to the morphological similarities among them. B. peregrina is widely distributed in South America and is considered a potential intermediate host of Schistosoma mansoni. We have reported the use of the polymerase chain reaction and restriction fragment length polymorphism analysis of the internal transcribed spacer region of the ribosomal DNA for the molecular identification of these snails. The snails were obtained from different localities of Argentina, Brazil and Uruguay. The restriction patterns obtained with MvaI enzyme presented the best profile to identify the three species. The profiles obtained with all enzymes were used to estimate genetic similarities among B. oligoza, B. peregrina and B. orbignyi. This is also the first report of B. orbignyi in Uruguay.