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.     

Endogenous development of Eimeria minasensis in experimentally infected goats

The endogenous development of Eimeria minasensis was studied in 9 coccidia-free goat kids inoculated with 10(5) sporulated oocysts/kg body weight. Kids were killed 4, 7 (2 animals), 10, 13, 16, 18, 19, and 22 days after inoculation (DAI). In tissue sections of the intestines stained with hematoxylin and eosin and examined by light microscopy, 2 generations of meronts, gamonts, gametes, and oocysts were found. The first generation of meronts developed in cells deep in the lamina propria of the jejunum and ileum. Mature giant meronts (299.4x243.8 microm) found 16 DAI were visible to the naked eye and contained a large number of crescent-shaped merozoites. The second generation of meronts developed in the epithelial cells of crypts of the ileum and above the host cell nuclei. Mature meronts (11.5x10.1 microm) with 18-28 comma-shaped merozoites were first seen 16 DAI. Gametogenesis took place in epithelial cells of the crypts and villi of the terminal part of the ileum, cecum, and colon. Macrogametes (27.8x17.6 microm), mature microgamonts (21.3x17.0 microm), microgametes, and oocysts (30.5x19.4 microm) were found 19 DAI. Sexual stages were below the host cell nucleus.     

Synthesis and characterization of a diruthenium-ibuprofenato complex comparing its anti-inflammatory activity with that of a copper(II)-ibuprofenato complex

The ibuprofen complex of diruthenium(II,III) was prepared and characterized by electronic (UV-Vis) and vibrational (FTIR) spectroscopies and thermogravimetry. The copper(II)-ibuprofenato complex was prepared by a different route from that described in the literature. Both complexes were tested in vivo for anti-inflammatory activity. Oral administration of the two complexes inhibited development of carrageenin-induced edema in rats, this inhibition being similar to that observed for oral administration of the parent drug (free ibuprofen). However, gastric irritation was lower as compared to that of ibuprofen. Diruthenium-ibuprofenato exhibited a protective effect at light intensity ulceration while the copper-ibuprofenato complex was more effective in the protection of severe intensity ulceration.