Styryl- and dihydrostyryl-2-pyrones derivatives from Polygala sabulosa

Two dihydrostyrylpyrones and a styrylpyrone were isolated from Polygala sabulosa, together with five known styrylpyrones. Their structures were established on the basis of spectral evidence as 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone, 4-methoxy-6-(11,12-methylenedioxy-10,14-dimethoxydihydrostyryl)-2-pyrone, and 4-methoxy-6-(11,12-methylenedioxy-14-methoxystyryl)-2-pyrone.     

Reproducibility and complications in gene searches: linkage on chromosome 6, heterogeneity, association, and maternal inheritance in juvenile myoclonic epilepsy

Evidence for genetic influences in epilepsy is strong, but reports identifying specific chromosomal origins of those influences conflict. One early study reported that human leukocyte antigen (HLA) markers were genetically linked to juvenile myoclonic epilepsy (JME); this was confirmed in a later study. Other reports did not find linkage to HLA markers. One found evidence of linkage to markers on chromosome 15, another to markers on chromosome 6, centromeric to HLA. We identified families through a patient with JME and genotyped markers throughout chromosome 6. Linkage analysis assuming equal male-female recombination probabilities showed evidence for linkage (LOD score 2.5), but at a high recombination fraction (theta), suggesting heterogeneity. When linkage analysis was redone to allow independent male-female thetas, the LOD score was significantly higher (4.2) at a male-female theta of.5,.01. Although the overall pattern of LOD scores with respect to male-female theta could not be explained solely by heterogeneity, the presence of heterogeneity and predominantly maternal inheritance of JME might explain it. By analyzing loci between HLA-DP and HLA-DR and stratifying the families on the basis of evidence for or against linkage, we were able to show evidence of heterogeneity within JME and to propose a marker associated with the linked form. These data also suggest that JME may be predominantly maternally inherited and that the HLA-linked form is more likely to occur in families of European origin.     

Intracellular Signal Triggered by Cholera Toxin in Saccharomyces boulardii and Saccharomyces cerevisiae

As is the case for Saccharomyces boulardii, Saccharomyces cerevisiae W303 protects Fisher rats against cholera toxin (CT). The addition of glucose or dinitrophenol to cells of S. boulardii grown on a nonfermentable carbon source activated trehalase in a manner similar to that observed for S. cerevisiae. The addition of CT to the same cells also resulted in trehalase activation. Experiments performed separately on the A and B subunits of CT showed that both are necessary for activation. Similarly, the addition of CT but not of its separate subunits led to a cyclic AMP (cAMP) signal in both S. boulardii and S. cerevisiae. These data suggest that trehalase stimulation by CT probably occurred through the cAMP-mediated protein phosphorylation cascade. The requirement of CT subunit B for both the cAMP signal and trehalase activation indicates the presence of a specific receptor on the yeasts able to bind to the toxin, a situation similar to that observed for mammalian cells. This hypothesis was reinforced by experiments with ¹²⁵I-labeled CT showing specific binding of the toxin to yeast cells. The adhesion of CT to a receptor on the yeast surface through the B subunit and internalization of the A subunit (necessary for the cAMP signal and trehalase activation) could be one more mechanism explaining protection against the toxin observed for rats treated with yeasts.     

Influence of the MexAB-OprM Multidrug Efflux System on Quorum Sensing in Pseudomonas aeruginosa

Pseudomonas aeruginosa nalB mutants which hyperexpress the MexAB-OprM multidrug efflux system produce reduced levels of several extracellular virulence factors known to be regulated by quorum sensing. Such mutants also produce less acylated homoserine lactone autoinducer PAI-1, consistent with an observed reduction in lasI expression. These data suggest that PAI-1 is a substrate for MexAB-OprM, and its resulting exclusion from cells hyperexpressing MexAB-OprM limits PAI-1-dependent activation of lasI and the virulence genes.     

The Fibronectin Domain ED-A Is Crucial for Myofibroblastic Phenotype Induction by Transforming Growth Factor-β1

Transforming growth factor-β1 (TGFβ1), a major promoter of myofibroblast differentiation, induces α-smooth muscle (sn) actin, modulates the expression of adhesive receptors, and enhances the synthesis of extracellular matrix (ECM) molecules including ED-A fibronectin (FN), an isoform de novo expressed during wound healing and fibrotic changes. We report here that ED-A FN deposition precedes α-SM actin expression by fibroblasts during granulation tissue evolution in vivo and after TGFβ1 stimulation in vitro. Moreover, there is a correlation between in vitro expression of α-SM actin and ED-A FN in different fibroblastic populations. Seeding fibroblasts on ED-A FN does not elicit per se α-SM actin expression; however, incubation of fibroblasts with the anti-ED-A monoclonal antibody IST-9 specifically blocks the TGFβ1-triggered enhancement of α-SM actin and collagen type I, but not that of plasminogen activator inhibitor-1 mRNA. Interestingly, the same inhibiting action is exerted by the soluble recombinant domain ED-A, but neither of these inhibitory agents alter FN matrix assembly. Our findings indicate that ED-A–containing polymerized FN is necessary for the induction of the myofibroblastic phenotype by TGFβ1 and identify a hitherto unknown mechanism of cytokine-determined gene stimulation based on the generation of an ECM-derived permissive outside in signaling, under the control of the cytokine itself.     

Phylogenetic relationships in Orchis and some related genera: an approach using chloroplast DNA

A chloroplast DNA restriction fragment length polymorphism analysis has been carried out on representatives species of Orchis (Orchidaceae) and of the allied genera Aceras, Dactylorhiza , and Anacamptis . One species of Cephalanthera and one of Serapias were used as outgroups. The consensus tree from a cladistic analysis showed that Orchis , as presently defined, is paraphyletic, as it contains also Aceras anthropophorum and Dactylorhiza saccifera . The genus Orchis is divided in two clades: one including O. laxiflora, O. papilionacea, O. coriophora , and O. morio in a ladderized sequence, the other showing D. saccifera at the base, followed by a clade in which a collapse of O. mascula, O. pauciflora, O. quadripunctata is sister group to a clade composed by O. italica, O. simia , and A. anthropophorum . These results, which agree to a great extent with literature evidence on chromosomes and isozymes, have been compared with various traditional systematic hypotheses for the genus.     

Creatine supplementation attenuates corticosteroid-induced muscle wasting and impairment of exercise performance in rats.

The objective of the present study was to investigate whether creatine (Cr) could attenuate the deleterious effects of high doses of dexamethasone (Dexa) on body mass, exercise performance, and respiratory variables of rodents. Forty-four Wistar rats performed incremental maximal exercise tests. They were then assigned to four groups: G1: subcutaneous (s.c.) and intraperitoneal (i.p.) saline; G2: s.c. saline and i.p. Cr (250 mg x kg(-1) x day(-1)); G3: s.c. Dexa (7.5 mg x kg(-1) x day(-1)) and i.p. saline; G4: s.c. Dexa and i.p. Cr. New exercise tests and analysis of the respiratory pattern under resting conditions and after stimulation with doxapram (2 mg/kg i.p.) were performed after 18 days. Post- minus pretreatment differences were compared between groups. G3 and G4 showed a significant impairment in body mass gain compared with G1 and G2 (P < 0.05) (G1: 65.3 +/- 26.1, G2: 93.1 +/- 27.4, G3: -18.4 +/- 20.1, G4: 9.8 +/- 23.1 kg x 10(-3)). Similar results were observed for maximal oxygen consumption (G1: 9.5 +/- 8.5, G2: 25.8 +/- 14.5, G3: -25.5 +/- 6.0, G4: -4.8 +/- 9.5 ml x kg(-1) x min(-1)) and test duration (G1: 43.0 +/- 45.0, G2: 72.0 +/- 59.5, G3: -165.0 +/- 60.6, G4: -48.0 +/- 48.5 s). Simultaneous use of Cr significantly attenuated the Dexa-induced impairment of the last two variables. Cr attenuated Dexa-induced gastrocnemius and diaphragm muscle weight losses and the atrophy of gastrocnemius type IIb fibers. Cr supplementation had only small effects on Dexa-induced respiratory changes. These results suggest that Cr may play a role in the prophylaxis or treatment of steroid-induced myopathy.     

Growth factors and glucose homeostasis in diabetic rats: effects of exercise training

To investigate the alterations of glucose homeostasis and variables of the insulin‐like growth factor‐1 (IGF‐1) growth system in sedentary and trained diabetic (TD) rats, Wistar rats were divided into sedentary control (SC), trained control (TC), sedentary diabetic (SD), and TD groups. Diabetes was induced by Alloxan (35 mg kg^?1 b.w.). Training program consisted of swimming 5 days week^?1, 1 h day^?1, during 8 weeks. Rats were sacrificed and blood was collected for determinations of serum glucose, insulin, growth hormone (GH), IGF‐1, and IGF binding protein‐3 (IGFBP‐3). Muscle and liver were removed to evaluate glycogen content. Cerebellum was extracted to determinate IGF‐1 content. Diabetes decreased serum GH, IGF‐1, IGFBP‐3, liver glycogen, and cerebellum IGF‐1 peptide content in baseline condition. Physical training recovered liver glycogen and increased serum and cerebellum IGF‐1 peptide in diabetic rats. Physical training induces important metabolic and hormonal alterations that are associated with an improvement in glucose homeostasis and serum and cerebellum IGF‐1 concentrations. Copyright © 2009 John Wiley & Sons, Ltd.