Splitting the sexes : The birth and senescence of sex chromosomes

The evolution of gonochorism from hermaphroditism can be gradual by increasing investment in one sex role while decreasing in the other, or rapid through the fixation of sex-role sterility mutations, eventually leading to the evolution of sex chromosomes. It is expected that the transition will involve a temporary state of gynodioecy or androdioecy as the mutations are not expected to take place at the same time. If the first mutation is a dominant female-sterility mutation, later accompanied by a recessive male sterility mutation, then an XY sex chromosome system evolves, while the opposite combination of mutations will result in a ZW system. Later on sexually antagonistic (SA) genes can be linked to the newly established sex-determining regions on the sex chromosomes. This is followed by recombination arrest in the region, so that the inheritance pattern is sex-limited for all these sex-specific genes. However, the lack of recombination leads to degeneration of the genetic content on the sexlimited chromosomes, since recombination is important for repairing mutations. Nevertheless, recombination arrest does not necessarily mean a dead-end for the sex-limited chromosomes. As our understanding of the very early stages of sex chromosome evolution is mainly based on theory and comparative evidence, we developed a system which we hoped would make it possible to observe in real time what happens after the acquisition of a new sex-determining gene. We used a previously established green fluorescent protein (GFP) line of the simultaneous hermaphrodite Macrostomum lignano. We used the GFP locus as a dominant sterility mutation, which is inherited in a Mendelian fashion. By allowing the GFP allele to be inherited only through sperm, we created male-limited selection lines (resembling the early stages in XY chromosome evolution), and by allowing the GFP allele to be inherited only through egg cells, we created female-limited selection lines (resembling the early stages in ZW chromosome evolution). We also created control lines, where the inheritance pattern was equally mixed. After tens of generations, we investigated how these lines have responded on the level of the genome, the transcriptome, and the phenotype. We sequenced genomes and analysed changes in SNP frequency and structural variant (SV) distribution in pairwise comparisons to see changes across the genome, but particularly on the scaffold where the GFP is located. We also sequenced transcriptomes and performed pairwise comparisons to detect differentially expressed genes, and analysed significant GO terms and KEGG pathways to see how the gene regulation has changed. Besides genomic analyses, we also looked at how mating behaviour (copulation frequency and duration, as well as probability of post-copulatory sucking behaviour) and sexual anatomy (gonad size and morphology of the male copulatory organ called stylet) has changed.We observed that the female-selected lines seemed to have responded the most at the genomic level. For example, the number of significantly differentially expressed transcripts was largest between the female-selected lines and the control lines. These changes seemed to involve downregulation of testes-biased genes. In addition, we observed the highest number of SVs in the female-selected lines, which could be related to changes in recombination rate. In contrast, the male-selected lines seemed to have responded the most at the phenotypic level, since we observed a decrease in the ovary size and body size in the male-selected lines, as well as behavioural changes that may be related to changes in the ejaculate. Both sex-specific selection regimes showed evidence of alterations in the shape of the stylet. Based on these results, we can conclude that our worms have indeed responded to the sex-limited selection in a way that is generally consistent with our expectations from other young sex chromosome systems. The evidence of a decrease in the testes function in the female-selected lines resembles adaptation towards gynodioecy, and the evidence of a decrease in the ovary size in the male-selected lines resembles adaptation towards androdioecy

Degenerate matrix method with Chebyshev nodes for solving nonlinear systems of differential equations

One of the simplest schemes of the degenerate matrix method with nodes as zeroes of Chebyshev polynomials of the second kind is considered. Performance of simple iterations and some modifications of Newton method for the discrete problem is compared. Išsigimusių matricų metodas netiesinių diferencialinių lygčių sprendimui Santrauka Šiame darbe toliau nagrinejamas išsigimusiu matricu metodas netiesiniu diferencialiniu lygčiu pradinio uždavinio sprendimui. Sudarant metodo algoritma naudojami antrojo tipo Cebyševo polinomu nuliai bei specialiai parenkamos konstantos aproksimuojant išvestines kvaziatvirkštine matrica. Metodas pritaikomas dvieju tipu iteraciniams algoritmams: paprastuju iteraciju ir Niutono metodams. Pateikiami skaitinio eksperimento rezultatai ir naujasis metodas palygintas su populiariaisiais skaitiniais algoritmais. First Published Online: 14 Oct 201

Degenerate matrices methods by splines for boundary values problems of ordinary differential equations

A method for numerical solving of boundary values problems of ordinary differential equations based on the use of splines and differentiation matrices with nodes as zeroes of classical orthogonal polynomials is considered. Possibilities of the method are shown by means of different examples. The method essentially uses the results obtained by Degenerate Matrices methods and it is applied for solving initial values problems of ordinary differential equations. Darbe nagrinejamas paprastuju lygčiu su kraštinemis salygomis skaitinis sprendimo metodas. Šio metodo pagrinda sudaro nereguliariuju matricu bei splainu konstravimas klasikiniu ortogonaliuju polinomu pavidalu. Nagrinejamo straipsnyje metodo taikymo galimybes parodytos ivairiais pavyzdžiais. First Published Online: 14 Oct 201

PVA Hydrogel Electrolyte and Porous Polyisoprene Carbon Nanostructure Composite Based Pressure Sensitive Supercapacitor

Special gratitude is in order to Raimonds Orlovs for temperature dependent resistance measurements. Financial support of project 1.1.1.1/16/A/013, “Hybrid energy harvesting systems” is greatly appreciated.Narrow operational voltage window can be considered as one of the greatest limitations for aqueous polymer electrolytes. Using freeze-thaw hydrogel preparation method we have synthesized wider potential window electrolytic polyvinyl alcohol (PVA)/Na2SO4 and PVA/K2SO4 electrolytes. Supercapacitors (SC) have been assembled using novel porous polyisoprene and carbon black composite electrodes. Our SC exhibit pressure sensitive properties therefore this effect is deeper explored here, giving explanation for capacitance increase during pressure application. It is found that up to 2 MPa the capacitance increases due to greater interface between electrode and electrolyte.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Shortwave Ultraviolet Persistent Luminescence of Sr2MgSi2O7: Pr3+

This research is funded by the Latvian Council of Science, project “Defect engineering of novel UV–C persistent phosphor materials”, Project no. lzp-2021/1-0118. Institute of Solid State Physics, University of Latvia, as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.Currently, extensive research activities are devoted to developing persistent phosphors which extend beyond the visible range. In some emerging applications, long-lasting emission of high-energy photons is required; however, suitable materials for the shortwave ultraviolet (UV–C) band are extremely limited. This study reports a novel Sr2MgSi2O7 phosphor doped with Pr3+ ions, which exhibits UV–C persistent luminescence with maximum intensity at 243 nm. The solubility of Pr3+ in the matrix is analysed by X-ray diffraction (XRD) and optimal activator concentration is determined. Optical and structural properties are characterised by photoluminescence (PL), thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) spectroscopy techniques. The obtained results expand the class of UV–C persistent phosphors and provide novel insights into the mechanisms of persistent luminescence. © 2023 by the authors.--//-- This is an open access article Antuzevics A., Doke G., Krieke G., Rodionovs P., Nilova D., Cirulis J., Fedotovs A., Rogulis U.; Shortwave Ultraviolet Persistent Luminescence of Sr2MgSi2O7: Pr3+ (2023) Materials, 16 (5), art. no. 1776; DOI: 10.3390/ma16051776; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149833044&doi=10.3390%2fma16051776&partnerID=40&md5=03c546fb3fc6c7d6c16d4d482b4038ca published under the CC BY 4.0 licence.Latvian Council of Science, Project no. lzp-2021/1-0118; Institute of Solid State Physics, University of Latvia, as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

The peripheral blood transcriptome in septic cardiomyopathy: an observational, pilot study.

BACKGROUND:Septic cardiomyopathy (SCM) is common in sepsis and associated with increased morbidity and mortality. Left ventricular global longitudinal strain (LV GLS), measured by speckle tracking echocardiography, allows improved identification of impaired cardiac contractility. The peripheral blood transcriptome may be an important window into SCM pathophysiology. We therefore studied the peripheral blood transcriptome and LV GLS in a prospective cohort of patients with sepsis. RESULTS:In this single-center observational pilot study, we enrolled adult patients (age > 18) with sepsis within 48 h of admission to the ICU. SCM was defined as LV GLS > - 17% based on echocardiograms performed within 72 h of admission. We enrolled 27 patients, 24 of whom had high-quality RNA results; 18 (75%) of 24 had SCM. The group was 50% female and had a median (IQR) age of 59.5 (48.5-67.0) years and admission APACHE II score of 21.0 (16.0-32.3). Forty-six percent had septic shock. After filtering for low-expression and non-coding genes, 15,418 protein coding genes were expressed and 73 had significantly different expression between patients with vs. without SCM. In patients with SCM, 43 genes were upregulated and 30 were downregulated. Pathway analysis identified enrichment in type 1 interferon signaling (adjusted p < 10-5). CONCLUSIONS:In this hypothesis-generating study, SCM was associated with upregulation of genes in the type 1 interferon signaling pathway. Interferons are cytokines that stimulate the innate and adaptive immune response and are implicated in the early proinflammatory and delayed immunosuppression phases of sepsis. While type 1 interferons have not been implicated previously in SCM, interferon therapy (for viral hepatitis and Kaposi sarcoma) has been associated with reversible cardiomyopathy, perhaps suggesting a role for interferon signaling in SCM