The extreme Beringian/Atlantic disjunction in Saxifraga rivularis (Saxifragaceae) has formed at least twice

Aim The oceanic Saxifraga rivularis L. presents one of the most extreme disjunctions known in the arctic flora: it has a small amphi‐Beringian range and a larger amphi‐Atlantic one. It was recently suggested to have had a single allopolyploid origin in Beringia at least one glacial cycle ago, followed by gradual expansion in a more humid period and differentiation into two allopatric subspecies (the Atlantic ssp. rivularis and the Beringian ssp. arctolitoralis). Here we explore the history of its extreme disjunction. Location The amphi‐Beringian and northern amphi‐Atlantic regions. Methods We obtained amplified fragment length polymorphisms (AFLPs) and chloroplast DNA sequences from 36 populations (287 individuals) and 13 populations (15 individuals), respectively. The data were analysed using principal coordinates analyses, Bayesian clustering methods, and analyses of molecular variance. Results Two distinctly divergent AFLP groups were observed, corresponding to the two described subspecies, but, surprisingly, four of the West Atlantic populations belonged to the supposedly Beringian endemic ssp. arctolitoralis. This was confirmed by re‐examination of their morphological characteristics. The overall AFLP diversity in the species was low (26.4% polymorphic markers), and there was no variation in the five investigated chloroplast DNA (cpDNA) regions. There was little geographic structuring of the AFLP diversity within each subspecies, even across the extreme disjunction in ssp. arctolitoralis, across the Bering Sea, and across the Atlantic Ocean, except that most plants from the arctic Svalbard archipelago formed a separate genetic group with relatively high diversity. Main conclusions The extreme disjunction in S. rivularis has evidently formed at least twice. The first expansion from Beringia was followed by allopatric differentiation into one Beringian and one Atlantic subspecies, which are distinctly divergent at AFLP loci but still harbour identical cpDNA haplotypes, suggesting that the expansion was quite recent but before the last glaciation. The next expansion from Beringia probably occurred by means of several long‐distance dispersals in the current interglacial, resulting in the colonization of the western Atlantic region by ssp. arctolitoralis. The poor geographic structuring within each subspecies suggests frequent long‐distance dispersals from two main Weichselian refugia, one Beringian and one western‐central European, but it is possible that the genetic group in Svalbard originates from an additional refugium.     

Pharmacokinetics and Interspecies Allometric Scaling of ST-246, an Oral Antiviral Therapeutic for Treatment of Orthopoxvirus Infection

Plasma pharmacokinetics of ST-246, smallpox therapeutic, was evaluated in mice, rabbits, monkeys and dogs following repeat oral administrations by gavage. The dog showed the lowest T_max of 0.83 h and the monkey, the highest value of 3.25 h. A 2- to 4-fold greater dose-normalized C_max was observed for the dog compared to the other species. The mouse showed the highest dose-normalized AUC, which was 2-fold greater than that for the rabbit and monkey both of which by approximation, recorded the lowest value. The Cl/F increased across species from 0.05 L/h for mouse to 42.52 L/h for dog. The mouse showed the lowest V_D/F of 0.41 L and the monkey, the highest V_D/F of 392.95 L. The calculated extraction ratios were 0.104, 0.363, 0.231 and 0.591 for mouse, rabbit, monkey and dog, respectively. The dog showed the lowest terminal half-life of 3.10 h and the monkey, the highest value of 9.94 h. The simple allometric human V_D/F and MLP-corrected Cl/F were 2311.51 L and 51.35 L/h, respectively, with calculated human extraction ratio of 0.153 and terminal half-life of 31.20 h. Overall, a species-specific difference was observed for Cl/F with this parameter increasing across species from mouse to dog. The human MLP-corrected Cl/F, terminal half-life, extraction ratios were in close proximity to the observed estimates. In addition, the first-in-humans (FIH) dose of 485 mg, determined from the MLP-corrected allometry Cl/F, was well within the dose range of 400 mg and 600 mg administered in healthy adult human volunteers.     

How to avoid pharmaceuticals in the aquatic environment

Pharmaceuticals and other micropollutants in wastewater pose a new challenge to wastewater professionals as well as to the pharmaceutical industry. Although there is a great deal of uncertainty concerning the possible detrimental effects on the aquatic ecosystems, the precautionary principle--or possibly new scientific evidence--may give rise to more stringent demands on wastewater treatment in the future. In conventional wastewater treatment plants, a combination of biological treatment with high sludge residence times and ozonation of the effluent seems to be the most promising technology. Ozonation, however, is an energy-intensive technology. Moreover, in conventional end-of-pipe systems a large part of the pollutants will always be lost to the environment due to leaking, primarily during rain. In the long term, source separation offers the more sustainable solution to the entire wastewater problem, including organic micropollutants. Urine source separation is an elegant solution to the problems of nutrients and pharmaceuticals alike and losses of untreated pollutants to the environment can be minimized. Although few technologies for the separate treatment of urine have been developed to date, the 100-500 times higher concentrations of micropollutants promise more efficient conditions for all removal technologies known from conventional wastewater treatment.     

Indolizine 1-sulfonates as potent inhibitors of 15-lipoxygenase from soybeans

A number of indolizine 1-sulfonates have been prepared by cyclization of cyclopropenones with pyridines followed by trapping of the intermediate 1-indolizinol with a sulfonyl halide, and examined as inhibitors of 15-lipoxygenase (15-LO). The compounds display IC(50) values between 15 and 42 microM; all are more active than the well-known 15-LO inhibitor quercetin (IC(50) 51 microM). A wide variety of substituents are well tolerated. The enzyme inhibition was not affected by preincubation or the presence of a detergent and no significant particle formation was observed. Hence, inhibition from aggregates of indolizines, promiscuous inhibition, is highly unlikely.     

Identification of an intragenic integration site for foreign gene expression in recombinant Streptococcus gordonii strains

A new intragenic chromosomal integration site within the lacG gene of the lac operon has been identified in Streptococcus gordonii for use in the expression of foreign genes. Introduction of a portion of the Streptococcus pyogenes emm6 gene into the lacG locus resulted in the lactose-inducible surface expression of the S. pyogenes M6 protein. This result demonstrates the ability to modulate the in vitro or in vivo expression of a foreign gene in a S. gordonii recombinant using a biosynthetic metabolite.     

Gpr116 Receptor Regulates Distinctive Functions in Pneumocytes and Vascular Endothelium

Despite its known expression in both the vascular endothelium and the lung epithelium, until recently the physiological role of the adhesion receptor Gpr116/ADGRF5 has remained elusive. We generated a new mouse model of constitutive Gpr116 inactivation, with a large genetic deletion encompassing exon 4 to exon 21 of the Gpr116 gene. This model allowed us to confirm recent results defining Gpr116 as necessary regulator of surfactant homeostasis. The loss of Gpr116 provokes an early accumulation of surfactant in the lungs, followed by a massive infiltration of macrophages, and eventually progresses into an emphysema-like pathology. Further analysis of this knockout model revealed cerebral vascular leakage, beginning at around 1.5 months of age. Additionally, endothelial-specific deletion of Gpr116 resulted in a significant increase of the brain vascular leakage. Mice devoid of Gpr116 developed an anatomically normal and largely functional vascular network, surprisingly exhibited an attenuated pathological retinal vascular response in a model of oxygen-induced retinopathy. These data suggest that Gpr116 modulates endothelial properties, a previously unappreciated function despite the pan-vascular expression of this receptor. Our results support the key pulmonary function of Gpr116 and describe a new role in the central nervous system vasculature.     

Cerebrovascular Diseases in Workers at Mayak PA: The Difference in Radiation Risk between Incidence and Mortality

A detailed analysis of cerebrovascular diseases (CeVD) for the cohort of workers at Mayak Production Association (PA) is presented. This cohort is especially suitable for the analysis of radiation induced circulatory diseases, due to the detailed medical surveillance and information on several risk factors. The risk after external, typically protracted, gamma exposure is analysed, accounting for potential additional internal alpha exposure. Three different endpoints have been investigated: incidence and mortality from all cerebrovascular diseases and incidence of stroke. Particular emphasis was given to the form of the dose-response relationship and the time dependence of the radiation induced risk. Young attained age was observed to be an important, aggravating modifier of radiation risk for incidence of CeVD and stroke. For incidence of CeVD, our analysis supports a dose response sub-linear for low doses. Finally, the excess relative risk per dose was confirmed to be significantly higher for incidence of CeVD compared to CeVD mortality and incidence of stroke. Arguments are presented for this difference to be based on a true biological effect.     

Src Drives Growth of Antiestrogen Resistant Breast Cancer Cell Lines and Is a Marker for Reduced Benefit of Tamoxifen Treatment

The underlying mechanisms leading to antiestrogen resistance in estrogen-receptor α (ER)-positive breast cancer is still poorly understood. The aim of this study was therefore to identify biomarkers and novel treatments for antiestrogen resistant breast cancer. We performed a kinase inhibitor screen on antiestrogen responsive T47D breast cancer cells and T47D-derived tamoxifen and fulvestrant resistant cell lines. We found that dasatinib, a broad-spectrum kinase inhibitor, inhibited growth of the antiestrogen resistant cells compared to parental T47D cells. Furthermore western blot analysis showed increased expression and phosphorylation of Src in the resistant cells and that dasatinib inhibited phosphorylation of Src and also signaling via Akt and Erk in all cell lines. Immunoprecipitation revealed Src: ER complexes only in the parental T47D cells. In fulvestrant resistant cells, Src formed complexes with the Human Epidermal growth factor Receptor (HER)1 and HER2. Neither HER receptors nor ER were co-precipitated with Src in the tamoxifen resistant cell lines. Compared to treatment with dasatinib alone, combined treatment with dasatinib and fulvestrant had a stronger inhibitory effect on tamoxifen resistant cell growth, whereas dasatinib in combination with tamoxifen had no additive inhibitory effect on fulvestrant resistant growth. When performing immunohistochemical staining on 268 primary tumors from breast cancer patients who had received tamoxifen as first line endocrine treatment, we found that membrane expression of Src in the tumor cells was significant associated with reduced disease-free and overall survival. In conclusion, Src was identified as target for treatment of antiestrogen resistant T47D breast cancer cells. For tamoxifen resistant T47D cells, combined treatment with dasatinib and fulvestrant was superior to treatment with dasatinib alone. Src located at the membrane has potential as a new biomarker for reduced benefit of tamoxifen.