Specificity of Lipoxygenase Pathways Supports Species Delineation in the Marine Diatom Genus Pseudo-nitzschia

Oxylipins are low-molecular weight secondary metabolites derived from the incorporation of oxygen into the carbon chains of polyunsaturated fatty acids (PUFAs). Oxylipins are produced in many prokaryotic and eukaryotic lineages where they are involved in a broad spectrum of actions spanning from stress and defense responses, regulation of growth and development, signaling, and innate immunity. We explored the diversity in oxylipin patterns in the marine planktonic diatom Pseudo-nitzschia. This genus includes several species only distinguishable with the aid of molecular markers. Oxylipin profiles of cultured strains were obtained by reverse phase column on a liquid chromatograph equipped with UV photodiode detector and q-ToF mass spectrometer. Lipoxygenase compounds were mapped on phylogenies of the genus Pseudo-nitzschia inferred from the nuclear encoded hyper-variable region of the LSU rDNA and the plastid encoded rbcL. Results showed that the genus Pseudo-nitzschia exhibits a rich and varied lipoxygenase metabolism of eicosapentaenoic acid (EPA), with a high level of specificity for oxylipin markers that generally corroborated the genotypic delineation, even among genetically closely related cryptic species. These results suggest that oxylipin profiles constitute additional identification tools for Pseudo-nitzschia species providing a functional support to species delineation obtained with molecular markers and morphological traits. The exploration of the diversity, patterns and plasticity of oxylipin production across diatom species and genera will also provide insights on the ecological functions of these secondary metabolites and on the selective pressures driving their diversification.     

A Clinical Evaluation of Statin Pleiotropy: Statins Selectively and Dose-Dependently Reduce Vascular Inflammation

Statins are thought to reduce vascular inflammation through lipid independent mechanisms. Evaluation of such an effect in atherosclerotic disease is complicated by simultaneous effects on lipid metabolism. Abdominal aortic aneurysms (AAA) are part of the atherosclerotic spectrum of diseases. Unlike atherosclerotic occlusive disease, AAA is not lipid driven, thus allowing direct evaluation of putative anti-inflammatory effects. The anti-inflammatory potency of increasing doses (0, 20 or 40 mg/day) simvastatin or atorvastatin was evaluated in 63 patients that were at least 6 weeks on statin therapy and who underwent open AAA repair. A comprehensive analysis using immunohistochemistry, mRNA and protein analyses was applied on aortic wall samples collected during surgery. The effect of statins on AAA growth was analyzed in a separate prospective study in incorporating 142 patients. Both statins equally effectively and dose-dependently reduced aortic wall expression of NFκB regulated mediators (i.e. IL-6 (P<0.001) and MCP-1 (P<0.001)); shifted macrophage polarization towards a M2 phenotype (P<0.0003); selectively reduced macrophage-related markers such as cathepsin K and S (P<0.009 and 0.0027 respectively), and ALOX5 (P<0.0009), and reduced vascular wall NFκB activity (40 mg/day group, P<0.016). No effect was found on other cell types. Evaluation of the clinical efficacy of statins to reduce AAA progression did not indicate an effect of statins on aneurysm growth (P<0.337). Hence, in the context of AAA the clinical relevance of statins pleiotropy appears minimal.     

NUCLEAR RIBOSOMAL DNA PHYLOGENY OF HALIMEDALES REVEALS SEVERAL POLYPHYLETIC GENERA

Halimedales (Chlorophyta) are widely distributed in reefs and lagoons throughout the tropics and subtropics. One genus, Chlorodesmis, consists of simple, branching siphons that persist into the mature sexual phase. In most other genera, only the juvenile stages exhibit such simple anatomy. Their mature, often‐calcified thalli possess complex siphonal anatomy and differentiation depending on the location in the thallus. We obtained a nuclear ribosomal DNA phylogeny encompassing many genera in order to unravel the evolution of this complexity. Results pinpoint Caulerpa as outgroup to a clade with all other genera included in this study. The first dichotomy separates Halimeda from the remaining genera. Distinct gametangial anatomy defines these two principal clades. Within the remainder, Tydemania and its sister Flabellia are nearest neighbors to a clade containing Rhipocephalus, Udotea, Penicillus and Chlorodesmis. The latter three genera are polyphyletic. Therefore, character states of thallus superstructure defining these genera appear to be homoplasies. Chlorodesmis represents a case of neoteny where the juvenile stage persists into reproductive maturity. We will evaluate which morphological characters do change state in agreement with the molecular phylogeny and can, therefore, serve as diagnostic characters for a more natural classification.     

Effects of aglépristone, a progesterone receptor antagonist, administered during the early luteal phase in non-pregnant bitches

Aglépristone, a progesterone receptor antagonist, was administered to six non-pregnant bitches in the early luteal phase in order to determine its effects on the duration of the luteal phase, the interestrous interval, and plasma concentrations of progesterone and prolactin. Aglépristone was administered subcutaneously once daily on two consecutive days in a dose of 10 mg/kg body weight, beginning 12 +/- 1 days after ovulation. Blood samples were collected before, during, and after administration of aglépristone for determination of plasma progesterone and prolactin concentrations. The differences in mean plasma concentration of progesterone and of prolactin before, during, and after treatment were not significant. Also, the duration of the luteal phase in the six treated bitches (72 +/- 6 days) did not differ significantly from that in untreated control dogs (74 +/- 4 days ). However, the intervals during which plasma progesterone concentration exceeded 64 and 32 nmol/l were significantly shorter in the six treated bitches than in untreated control dogs. The interestrous interval was significantly shorter in beagle bitches treated with aglépristone (158 +/- 16 days) than in the same group prior to treatment (200 +/- 5 days ). It is concluded that administration of aglépristone during the early luteal phase in the non-pregnant bitch affects progesterone secretion, but not sufficiently to shorten the luteal phase. The shortening of the interestrous interval suggests that aglépristone administered in the early luteal phase influences the hypothalamic-pituitary-ovarian axis.     

Structure of a highly phosphorylated lipopolysaccharide core in the Delta algC mutants derived from Pseudomonas aeruginosa wild-type strains PAO1 (serogroup O5) and PAC1R (serogroup O3)

Lipopolysaccharides (LPS) were isolated from rough-type mutant strains of Pseudomonas aeruginosa (Delta algC) derived from wild-type strains PAO1 (serogroup O5) and PAC1R (serogroup O3). Structural studies of the LPS core region with a special focus on the phosphorylation pattern were performed by 2D NMR spectroscopy, including a 1H,(31)P HMQC-TOCSY experiment, MALDI-TOF MS, and Fourier-transform ion cyclotron resonance ESIMS using the capillary skimmer dissociation technique. Both LPS were found to contain two residues each of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) and L-glycero-D-manno-heptose (Hep), one residue of N-(L-alanyl)-D-galactosamine and one O-carbamoyl group (Cm) on the distal Hep residue. The following structures of a tetrasaccharide trisphosphate from strain PAC1R Delta algC and that carrying an additional ethanolamine phosphate group (PEtN) from strain PAO1 Delta algC were elucidated: [carbohydrate structre: see text] where R=P in PAC1R Delta algC and PPEtN in PAO1 Delta algC. To our knowledge, in this work the presence of ethanolamine diphosphate is unambiguously confirmed and its position established for the first time in the LPS core of a rough-type strain of P. aeruginosa. In addition, the structure of the complete LPS core of wild-type strain P. aeruginosa PAO1 was reinvestigated and the position of the phosphorylation sites was revised.     

Pulsatile secretion pattern of growth hormone during the luteal phase and mid-anoestrus in beagle bitches

The pulsatile secretion pattern of growth hormone was investigated during four stages of the luteal phase and during mid-anoestrus in six cyclic beagle bitches. Plasma samples were obtained via jugular venepuncture at 10 min intervals for 12 h at 19 +/- 2 (mean +/- SEM; luteal phase 1), 38 +/- 2 (luteal phase 2), 57 +/- 2 (luteal phase 3), 78 +/- 2 (luteal phase 4) and 142 +/- 4 days (mid-anoestrus) after ovulation. During all stages, growth hormone was secreted in a pulsatile fashion. The mean basal plasma growth hormone concentration during luteal phase 1 (2.2 +/- 0.3 microgram l(-1)) was significantly higher than that during luteal phase 4 (1.5 +/- 0.1 microgram l(-1)) and mid-anoestrus (1.4 +/- 0.2 microgram l(-1)). The mean area under the curve (AUC) above zero during luteal phase 1 (27.3 +/- 2.7 microgram l(-1) in 12 h) tended to be higher than that during luteal phase 4 (20.8 +/- 1.8 microgram l(-1) in 12 h) and mid-anoestrus (19.2 +/- 2.5 microgram l(-1) in 12 h). In contrast, the mean AUCs above the baseline during luteal phase 1 (1.1 +/- 0.5 microgram l(-1) in 12 h) and luteal phase 2 (1.2 +/- 0.5 microgram l(-1) in 12 h) were significantly lower than that during luteal phase 4 (2.8 +/- 0.5 microgram l(-1) in 12 h). In conclusion, the pulsatile secretion pattern of growth hormone changes during the luteal phase in healthy cyclic bitches: basal growth hormone secretion is higher and less growth hormone is secreted in pulses during stages in which the plasma progesterone concentration is high. It is hypothesized that this change is caused by a partial suppression of pituitary growth hormone release by progesterone-induced growth hormone production in the mammary gland. The progesterone-induced production of growth hormone in the mammary gland may promote the physiological proliferation and differentiation of mammary gland tissue during the luteal phase of the bitch by local autocrine-paracrine effects. In addition, progesterone-induced mammary growth hormone production may exert endocrine effects, such as hyperplastic changes in the uterine epithelium and insulin resistance.     

New Insights into Plagiogrammaceae (Bacillariophyta) Based on Multigene Phylogenies and Morphological Characteristics with the Description of a New Genus and Three New Species

Plagiogrammaceae, a poorly described family of diatoms, are common inhabitants of the shallow marine littoral zone, occurring either in the sediments or as epiphytes. Previous molecular phylogenies of the Plagiogrammaceae were inferred but included only up to six genera: Plagiogramma, Dimeregramma, Neofragilaria, Talaroneis, Psammogramma and Psammoneis. In this paper, we describe a new plagiogrammoid genus, Orizaformis, obtained from Bohai Sea (China) and present molecular phylogenies of the family based on three and four genes (nuclear-encoded large and small subunit ribosomal RNAs and chloroplast-encoded rbcL and psbC). Also included in the new phylogenies is Glyphodesmis. The phylogenies suggest that the Plagiogrammaceae is composed of two major clades: one consisting of Talaroneis, Orizaformis and Psammoneis, and the second of Glyphodesmis, Psammogramma, Neofragilaria, Dimeregramma and Plagiogramma. In addition, we describe three new species within established genera: Psammoneis obaidii, which was collected from the Red Sea, Saudi Arabia; and Neofragilaria stilus and Talaroneis biacutifrons from the Mozambique Channel, Indian Ocean, and illustrate two new combination taxa: Neofragilaria anomala and Neofragilaria lineata. Our observations suggest that the biodiversity of the family is strongly needed to be researched, and the phylogenetic analyses provide a useful framework for future studies of Plagiogrammaceae.