Deep genetic divergence and recent radiations in sand goby <i>Pomatoschistus minutus</i> along European coasts

Understanding evolutionary patterns is more complex in marine compared to continental species because marine species have high effective population sizes and high levels of dispersal due to an apparent lack of barriers. Moreover, phylogeographical breaks in the marine realm such as the Atlantic-Mediterranean transition remain controversial. Therefore a new high-quality phylogeographic analysis was realized for a marine demersal fish, the sand goby Pomatoschistus minutus (Gobiidae, Teleostei). Sand gobies of 12 locations along the full European distribution range were analyzed by sequencing a large fragment of the mitochondrial cytochrome b gene.The phylogenetic results show that P. minutus comprises two deep genealogical lineages, the Mediterranean Sea Clade (MS-Clade) and the Atlantic Ocean Clade (AOClade), that date back to the Early Pleistocene (1.6-0.8 MYA). Even though the sand goby occurs only in a few northern locations in the Mediterranean, the MS-Clade contains the Significant Units (ESU), one off the Western Iberian Peninsula and the other in the marine systems of the North Atlantic (Bay of Biscay, North Sea, Irish Sea and Baltic Sea). This is consistent with two separate palaeorefugia during the Pleistocene glaciations: the Iberian Peninsula and the Bay of Biscay. Less haplotypes were shared among the marine systems of the North Atlantic, indicating a low present-day gene flow. The network analysis showed a recent radiation in each marine system, even in the northern Baltic Sea where the recolonization of P. minutus occurred only 8000 years ago. This phylogeographic pattern will be compared with putatively adaptive loci in order to study the characteristics of local adaptation in the marine environment

Exploring glacial and present evolutionary patterns of a marine goby, <i>Pomatoschistus minutus</i>

A classical understanding of marine fishes is that they have high effective population sizes and high levels of dispersal due to an apparent lack of barriers in the marine environment. The realization of a genetic population structure is therefore thought to be a slow process. To gain insights in this process, it is a challenge to disentangle the interaction between selection, gene flow, population history and genetic drift. The sand goby (Pomatoschistus minutus), which is an important ecological but noncommercial species, was chosen to distinguish between natural and anthropologically induced processes. A spatio-temporal analysis with samples from different localities throughout the species distribution and with two types of genetic markers was performed to assess the neutral genetic population structure. Phylogeographical patterns were studied by sequence cytochrome b (mtDNA). Nine new nuclear microsatellites were developed and used to describe the current genetic diversity and population structure. The genetic structure of the sand goby is best explained by a combination of present and historic factors. Due to its high potential for dispersion and high effective population size, it shows the typical features of a marine fish with a high level of diversity and a limited degree of genetic differentiation. The large genetic distance between the Venetian and all other samples shows that the sand gobies from the Adriatic Sea should be considered as a distinct cryptic species of the genus Pomatoschistus. Low but significant differentiation is observed between Atlantic and western Mediterranean P. minutus. In the Atlantic and Baltic basins, there is evidence for a postglacial range expansion and a weak pattern of isolation-by-distance. Furthermore the results support the hypothesis of a glacial refugium and a fine-scale genetic structure in the southern North Sea. The neutral genetic pattern will be compared with putatively adaptive loci in order to study the genomic characteristics of local adaptation in the marine environment. This should provide a better understanding of how fish respond to changes in the environment

Search for Rayleigh scattering in the atmosphere of GJ1214b

We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet towards the blue. We observed the transit of GJ1214b in the B-band with the FOcal Reducing Spectrograph (FORS) at the Very Large Telescope (VLT) and in the g-band with both ACAM on the William Hershel Telescope (WHT) and the Wide Field Camera (WFC) at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B-band of 0.1162+/-0.0017, and in the g-band 0.1180+/-0.0009 and 0.1174+/-0.0017 for the WHT & INT observations respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered a small scale-height water-dominated model fits the data best.Comment: Accepted for publication in Ap

Toward the use of diffuse reflection spectroscopy for intra-operative tissue discrimination during sarcoma surgery

Significance: Accurately distinguishing tumor tissue from normal tissue is crucial to achieve complete resections during soft tissue sarcoma (STS) surgery while preserving critical structures. Incomplete tumor resections are associated with an increased risk of local recurrence and worse patient prognosis. Aim: We evaluate the performance of diffuse reflectance spectroscopy (DRS) to distinguish tumor tissue from healthy tissue in STSs. Approach: DRS spectra were acquired from different tissue types on multiple locations in 20 freshly excised sarcoma specimens. A k -nearest neighbors classification model was trained to predict the tissue types of the measured locations, using binary and multiclass approaches. Results: Tumor tissue could be distinguished from healthy tissue with a classification accuracy of 0.90, sensitivity of 0.88, and specificity of 0.93 when well-differentiated liposarcomas were included. Excluding this subtype, the classification performance increased to an accuracy of 0.93, sensitivity of 0.94, and specificity of 0.93. The developed model showed a consistent performance over different histological subtypes and tumor locations. Conclusions: Automatic tissue discrimination using DRS enables real-time intraoperative guidance, contributing to more accurate STS resections.</p

The oncological outcomes of isolated limb perfusion and neo-adjuvant radiotherapy in soft tissue sarcoma patients:A nationwide multicenter study

Introduction: Patients with locally extensive high-grade extremity soft tissue sarcomas (eSTS) are often presented in multidisciplinary teams to decide between ablative surgery (amputation) or limb-salvage surgery supplemented with either neo-adjuvant radiotherapy (RT) or induction isolated limb perfusion (ILP). In The Netherlands, ILP typically aims to reduce the size of tumors that would otherwise be considered irresectable, whereas neo-adjuvant RT aims mainly at improving local control and reducing morbidity of required marginal margins. This study presents a 15-year nationwide cohort to describe the oncological outcomes of both pre-operative treatment strategies. Methods: All consecutive patients with locally extensive primary high-grade eSTS surgically treated between 2000 and 2015 at five tertiary sarcoma centers that received neo-adjuvant ILP or RT were included. 169 patients met the inclusion criteria (89 ILP, 80 RT). Median follow-up was 7.3 years. Results: Limb salvage was achieved in 84% of cases in the ILP group (80% for patients with amputation indication) and 96% of cases in the RT group. 5-Year overall survival was 47% in the ILP group, 69% in the RT group. 5-Year local recurrence rate was 14% in the ILP group, 10% in the RT group. Distant metastasis rate was 55% in the ILP group, 36% in the RT group. Conclusion: We find oncological outcomes and limb salvage rates in line with existing literature for both treatment modalities. Whether the tumor was locally advanced with an indication for induction therapy to prevent amputation or morbid surgery appeared to be the main determinant in choosing between neo-adjuvant ILP or RT

What clinical trials are needed for treatment of leiomyosarcoma?

Leiomyosarcoma is one of the most common subtypes of soft tissue sarcomas accounting for approximately 20% of sarcomas. As leiomyosarcoma patients frequently develop metastatic disease, effective systemic therapies are needed to improve clinical outcomes. The overall activity of the currently available conventional systemic therapies and the prognosis of patients with advanced and/or metastatic disease are poor. As such, the treatment of this patient population remains challenging. As a result, there is a clear unmet medical need, and designing and performing meaningful clinical studies are of utmost importance to improve the prognosis of this patient group. Therefore, the aim of this review is to briefly summarize state-of-the-art treatments for leiomyosarcoma patients and to describe trial characteristics needed for informative clinical studies