Antimicrobial isoflavonoids from Erythrina crista galli infected with Phomopsis sp

The isoflavonoids coumestrol, genistein and daidzein have been isolated and identified by bioassay-guided fractionation from the acetone extract of Erythrina crista galli young twigs infected with Phomopsis sp. These compounds showed antimicrobial activity against Bacillus brevis (MIC values 16.3, 64.8 and 137.8 microM, respectively). This is the first time that coumestrol, besides lutein and n-nonacosane, are reported in this species.     

Phomopsidone, a novel depsidone from an endophyte of the medicinal plant Eupatorium arnottianum

The medicinal plant Eupatorium arnottianum can be found in the Northeast and center of Argentina and the South of Bolivia. From plant material collected in Argentina an endophytic Phomopsis was isolated. The fungus was identified by microscopic features and analysis of its ITS sequence. Cultures yielded, besides mellein and nectriapyrone, a novel depsidone derivative for which we propose the name phomopsidone (1). The structure of 1 was determined from its spectroscopic data.     

HCMV-infection in a human arterial organ culture model: effects on cell proliferation and neointimal hyperplasia

Background

The impact of infections with the human cytomegalovirus (HCMV) for the development of atherosclerosis and restenosis is still unclear. Both a clear correlation and no correlation at all have been reported in clinical, mostly serological studies. In our study we employed a human non-injury ex vivo organ culture model to investigate the effect of an in vitro permissive HCMV-infection on cell proliferation and neointimal hyperplasia for a period of 56 days.

Results

During routine-nephrectomies parts of renal arteries from 71 patients were obtained and prepared as human organ cultures. Cell free HCMV infection was performed with the fibroblast adapted HCMV strain AD169, the endotheliotropic strain TB40E, and a clinical isolate (AN 365). After 3, 7, 14, 21, 28, 35, and 56 days in culture staining of HCMV-antigens was carried out and reactive cell proliferation and neointimal thickening were analysed. Successful HCMV-infection was accomplished with all three virus strains studied. During the first 21 days in organ culture no cell proliferation or neointimal hyperplasia was detected. At day 35 and day 56 moderate cell proliferation and neointimal hyperplasia was found both in HCMV-infected segments and mock infected controls. Neointimal hyperplasia in productively HCMV-infected segments was lower than in non infected at day 35 and day 56, but relatively higher after infection with the endotheliotropic TB40E in comparison with the two other strains.

Conclusion

The data do not support the hypothesis that HCMV-infection triggers restenosis via a stimulatory effect on cell proliferation and neointimal hyperplasia in comparison to non infected controls. Interestingly however, even after lytic infection, a virus strain specific difference was observed.     

microRNA‐379 couples glucocorticoid hormones to dysfunctional lipid homeostasis

In mammals, glucocorticoids (GCs) and their intracellular receptor, the glucocorticoid receptor (GR), represent critical checkpoints in the endocrine control of energy homeostasis. Indeed, aberrant GC action is linked to severe metabolic stress conditions as seen in Cushing's syndrome, GC therapy and certain components of the Metabolic Syndrome, including obesity and insulin resistance. Here, we identify the hepatic induction of the mammalian conserved microRNA (miR)‐379/410 genomic cluster as a key component of GC/GR‐driven metabolic dysfunction. Particularly, miR‐379 was up‐regulated in mouse models of hyperglucocorticoidemia and obesity as well as human liver in a GC/GR‐dependent manner. Hepatocyte‐specific silencing of miR‐379 substantially reduced circulating very‐low‐density lipoprotein (VLDL)‐associated triglyceride (TG) levels in healthy mice and normalized aberrant lipid profiles in metabolically challenged animals, mediated through miR‐379 effects on key receptors in hepatic TG re‐uptake. As hepatic miR‐379 levels were also correlated with GC and TG levels in human obese patients, the identification of a GC/GR‐controlled miRNA cluster not only defines a novel layer of hormone‐dependent metabolic control but also paves the way to alternative miRNA‐based therapeutic approaches in metabolic dysfunction.     

The effect of rFVIIa on pro- and anti-inflammatory cytokines in serum and cerebrospinal fluid in a swine model of traumatic brain injury

Traumatic brain injury (TBI) is associated with significant infectious and inflammatory complications. Though increasing evidence suggests that rFVIIa administration may be efficacious for the pre-hospital treatment of TBI, the FVIIa-tissue factor complex has been shown to be immunologically active. To date the cytokine response to rFVIIa administration for the treatment of TBI has not been evaluated. Twenty anesthetized immature Yorkshire swine underwent fluid percussion TBI. At 15 min following injury, animals were randomized to receive either 90 μg/kg rFVIIa (rFVIIa) or nothing. Animals were observed for 6 h and then euthanized. Plasma and cerebrospinal (CSF) samples were collected at 0 min and 360 min, and ELISA analysis of TNF-α, IL-1β and IL-10 was performed. Survival in both groups was 100%. Baseline cytokine concentrations were not statistically different between rFVIIa and control animals in plasma or CSF. Animals in both groups did not have significant changes in plasma cytokine concentrations following TBI. Control animals did not demonstrate significant changes from baseline of CSF cytokine concentrations following TBI. The administration of rFVIIa however, resulted in significant increases in CSF TNF-α concentration (232.0 pg/ml ± 75.9 vs 36.4 pg/ml ± 10.4, p = 0.036) and IL-10 concentration (10.7 pg/ml ± 0.6 vs 8.8 pg/ml ± 0.1, p = 0.015). IL-1β concentrations were not significantly changed over the experimental time course. These results suggest that rFVIIa administration for the treatment of TBI is not immunologically inert, and is associated with increased CSF concentrations of TNF-α and IL-10.     

Depicting more accurate pictures of protistan community complexity using pyrosequencing of hypervariable SSU rRNA gene regions

Initial environmental pyrosequencing studies suggested highly complex protistan communities with phylotype richness decisively higher than previously estimated. However, recent studies on individual bacteria or artificial bacterial communities evidenced that pyrosequencing errors may skew our view of the true complexity of microbial communities. We pyrosequenced two diversity markers (hypervariable regions V4 and V9 of the small-subunit rDNA) of an intertidal protistan model community, using the Roche GS-FLX and the most recent GS-FLX Titanium sequencing systems. After pyrosequencing 24 reference sequences we obtained up to 2039 unique tags (from 3879 V4 GS-FLX Titanium reads), 77% of which were singletons. Even binning sequences that share 97% similarity still emulated a pseudodiversity exceeding the true complexity of the model community up to three times (V9 GS-FLX). Pyrosequencing error rates were higher for V4 fragments compared with the V9 domain and for the GS-FLX Titanium compared with the GS-FLX system. Furthermore, this experiment revealed that error rates are taxon-specific. As an outcome of this study we suggest a fast and efficient strategy to discriminate pyrosequencing signals from noise in order to more realistically depict the structure of protistan communities using simple tools that are implemented in standard tag data-processing pipelines.     

Budding yeast Mph1 promotes sister chromatid interactions by a mechanism involving strand invasion

Stalling of replication forks at lesions is a serious threat to genomic integrity and cell viability. Cells have developed a variety of pathways that allow continuation of synthesis, including translesion synthesis, postreplication repair and homologous recombination. We have devised a sensitive genetic system for detection of sister chromatid interactions in Saccharomyces cerevisiae. A 266bp sequence duplication in the KanMX4 module was generated and reversions were scored via G418 resistant colonies. Both 4-NQO induced and spontaneous reversions are strictly dependent on RAD52. Damage-induced reversions are also largely dependent on RAD51. Thus, most damage-induced events require a strand invasion step. Induced reversions were not affected in rev3 mutants and partially reduced in rad30 mutants indicating an involvement of Pol η. In cells lacking Mph1, a member of the FANCM family of DNA helicases, that has been implicated in a pathway for fork reactivation involving homologous recombination, damage-induced events are significantly reduced. Together with the spontaneous mutator phenotype of mph1 mutants this data strongly suggest that Mph1 has an additional function in recombination besides its previously described ability to disrupt D-loops. We propose that Mph1 promotes D-loop formation.