Phylogenetic relationship and antifouling activity of bacterial epiphytes from the marine alga Ulva lactuca

It is widely accepted that bacterial epiphytes can inhibit the colonization of surfaces by common fouling organisms. However, little information is available regarding the diversity and properties of these antifouling bacteria. This study assessed the antifouling traits of five epiphytes of the common green alga, Ulva lactuca . All isolates were capable of preventing the settlement of invertebrate larvae and germination of algal spores. Three of the isolates also inhibited the growth of a variety of bacteria and fungi. Their phylogenetic positions were determined by 16S ribosomal subunit DNA sequencing. All isolates showed a close affiliation with the genus Pseudoalteromonas and, in particular, with the species P. tunicata . Strains of this bacterial species also display a variety of antifouling activities, suggesting that antifouling ability may be an important trait for members of this genus to be highly successful colonizers of animate surfaces and for such species to protect their host against fouling.     

Integrin αvβ3 Requirement for Sustained Mitogen-activated Protein Kinase Activity during Angiogenesis

Angiogenesis depends on growth factors and vascular cell adhesion events. Integrins and growth factors are capable of activating the ras/MAP kinase pathway in vitro, yet how these signals influence endothelial cells during angiogenesis is unknown. Upon initiation of angiogenesis with basic fibroblast growth factor (bFGF) on the chick chorioallantoic membrane (CAM), endothelial cell mitogen-activated protein (MAP) kinase (ERK) activity was detected as early as 5 min yet was sustained for at least 20 h. The initial wave of ERK activity (5–120 min) was refractory to integrin antagonists, whereas the sustained activity (4–20 h) depended on integrin αvβ3, but not β1 integrins. Inhibition of MAP kinase kinase (MEK) during this sustained αvβ3-dependent ERK signal blocked the formation of new blood vessels while not influencing preexisting blood vessels on the CAM. Inhibition of MEK also blocked growth factor induced migration but not adhesion of endothelial cells in vitro. Therefore, angiogenesis depends on sustained ERK activity regulated by the ligation state of both a growth factor receptor and integrin αvβ3.     

Cycles of famine and feast: the starvation and outgrowth strategies of a marineVibrio

Studies of starvation survival in non-differentiating bacteria have largely focused on physiological changes and regulatory aspects of a few master regulators such as the signal molecule ppGpp and the stationary phase alternative sigma factor, sigma S. Recent findings have implicated a series of novel key events for the entry as well as exit from starvation. The importance of alternative sigma factors other than sigma S is emerging. In addition, low molecular weight extracellular signals have been demonstrated to be essential for the induction and mediation of several adaptive responses. The importance of mRNA modification and stability for starvation survival as well as outgrowth is receiving renewedinterest. In this paper, we present the results obtained from studies of starvation survival and recovery ofVibrio sp. strain S14.     

Serotonin Depletion-Induced Maladaptive Aggression Requires the Presence of Androgens

The sex hormone testosterone and the neurotransmitter serotonin exert opposite effects on several aspects of behavior including territorial aggression. It is however not settled if testosterone exerts its pro-aggressive effects by reducing serotonin transmission and/or if the anti-aggressive effect of serotonin requires the presence of the androgen. Using the resident intruder test, we now show that administration of the serotonin synthesis inhibitor para-chlorophenylalanine (300 mg/kg x 3 days) increases the total time of attack as well as the percentage amount of social behavior spent on attack but not that spent on threat – i.e. that it induces a pattern of unrestricted, maladaptive aggression – in gonadectomized C57Bl/6 male mice receiving testosterone replacement; in contrast, it failed to reinstate aggression in those not given testosterone. Whereas these results suggest the pro-aggressive effect of testosterone to be independent of serotonin, and not caused by an inhibition of serotonergic activity, the pCPA-induced induction of maladaptive aggression appears to require the presence of the hormone. In line with these findings, pCPA enhanced the total time of attack as well the relative time spent on attacks but not threats also in wild-type gonadally intact male C57Bl/6 mice, but failed to reinstate aggression in mice rendered hypo-aggressive by early knock-out of androgen receptors in the brain (AR^NesDel mice). We conclude that androgenic deficiency does not dampen aggression by unleashing an anti-aggressive serotonergic influence; instead serotonin seems to modulate aggressive behavior by exerting a parallel-coupled inhibitory role on androgen-driven aggression, which is irrelevant in the absence of the hormone, and the arresting of which leads to enhanced maladaptive aggression.     

Development of a treatment solution for reductive dechlorination of hexachloro-1,3-butadiene in vadose zone soil

The biodegradation of chlorinated organics in vadose zone soils is challenging owing to the presence of oxygen, which inhibits reductive dehalogenation reactions and consequently the growth of dehalorespiring microbes. In addition, the hydraulic conductivity of vadose zone soils is typically high, hence attempts to remediate such zones with biostimulation solutions are often unsuccessful due to the short residence times for these solutions to act upon the native bacterial community. In this study we have identified sodium alginate as a hydrogel polymer that can be used to increase the residence time of a nutrient solution in an unsaturated sandy soil. Additionally we have identified neutral red as a redox active compound that can catalyse the reductive dechlorination of the chlorinated organic hexachloro-1,3-butadiene by activated sludge fed with lactate and acetate. Finally we have shown that a nutrient solution amended with neutral red and sodium alginate can lower the redox potential and reduce hexachloro-1,3-butadiene concentrations in a contaminated vadose zone soil.     

Novel Fatty Acid Modifications of Transportan 10

Cell-penetrating peptides (CPPs) are able to efficiently internalize into cells and can therefore be used as vectors for non-viral cellular delivery of different cargoes. Previous studies have shown that hydrophobic modifications of different CPPs can increase their transfection efficiency dramatically. In this study we have modified the cell penetrating-peptide transportan 10 (TP10) with a variety of hydrophobic molecules to determine the role of hydrophobicity in the uptake of these molecules. The results can be used to synthesize more efficient delivery vectors. To evaluate how these constructs are able to transport cargoes into cells we used 2′-OMe splice correcting oligonucleotides. Non-covalent peptide-cargo complexes were formed and their transfection efficiency was measured using a luciferase readout system. The hydrophobicity of the novel modifications was correlated with their biological efficacy. We determined the most efficient range of hydrophobicity for TP10 analogs for delivering oligonucleotides into cells. In order to assess how the transfection efficacy of these particles is dependent on their size the hydrodynamic diameter of the formed nanoparticles was measured using dynamic light scattering. These findings will be used to develop highly efficient non-viral gene therapy vectors.     

Lost and found: the enigmatic large-billed reed warbler Acrocephalus orinus rediscovered after 139 years

We present compelling evidence of the continued existence of the large-billed reed warbler Acrocephalus orinus , hitherto known only from the unique type specimen collected in NW India 139 years ago. Morphological and genetic analyses of an unusual Acrocephalus warbler mist-netted south-west of Bangkok, Thailand, on 27 March 2006, confirmed its identity as A. orinus , and revealed that it was heterozygous at four out of eight microsatellite markers, indicating the continued existence of a viable population whose breeding and wintering areas are still unknown.     

Molecular investigation of the distribution, abundance and diversity of the genus Pseudoalteromonas in marine samples

The genus Pseudoalteromonas has attracted interest because it has frequently been found in association with eukaryotic hosts, and because many Pseudoalteromonas species produce biologically active compounds. One distinct group of Pseudoalteromonas species is the antifouling subgroup containing Pseudoalteromonas tunicata and Ps. ulvae, which both produce extracellular compounds that inhibit growth and colonization by different marine organisms. PCR primers targeting the 16S rRNA gene of the genus Pseudoalteromonas and the antifouling subgroup were developed and applied in this study. Real-time quantitative PCR (qPCR) was applied to determine the relative bacterial abundance of the genus and the antifouling subgroup, and denaturing gradient gel electrophoresis (DGGE) was applied to study the diversity of the genus in 11 different types of marine samples from Danish coastal waters. The detection of Ps. tunicata that contain the antifouling subgroup was achieved through specific PCR amplification of the antibacterial protein gene (alpP). The Pseudoalteromonas species accounted for 1.6% of the total bacterial abundance across all samples. The Pseudoalteromonas diversity on the three unfouled marine organisms Ciona intestinalis, Ulva lactuca and Ulvaria fusca was found to be low, and Ps. tunicata was only detected on these three hosts, which all contain accessible cellulose polymers in their cell walls.