Skeletal anomalies affect animal welfare and cause important economic problems in aquaculture. Despite the high frequency of skeletal problems in reared Solea senegalensis, there is lack of ...information regarding the histological features of normal and deformed vertebrae in this flatfish. The aim of this study was to describe the histopathological and radiographical appearance of vertebral body anomalies. Sixty-seven juvenile fish were radiographically examined 104 or 105 days after hatching. Through radiographic images, vertebral segments were selected and processed for histopathological examination from 7 normal and 7 affected fish. Alterations in bone shape and vertebral fusion were the most significant anomalies in the vertebral bodies. These alterations occurred most frequently between the last 3 abdominal vertebrae and the first 10 caudal centra. Radiographically, deformed vertebrae showed flattening of the endplates and narrowing of the intervertebral spaces. The radiographic findings concurred with the histological lesions where affected vertebrae exhibited irregular endplates and changes in trabecular bone. Radiolucent cartilaginous tissue was evident in the endplates of the deformed vertebra and, in some cases, the cartilaginous material extended from the growth zone into the intervertebral space. These changes were likely the primary alterations that led to vertebral fusion. Fused vertebrae were often reshaped and showed a reorganization of the trabeculae. The formation of metaplastic cartilage is frequent in a variety of anomalies affecting teleost species.
The disposal of high-level radioactive waste (HLW) represents a complex challenge with socio-technical and political dimensions. This article analyses different modes of governance for HLW disposal ...and focuses on the conditions affecting transparency, trust and participation in four countries of the European Union. Whilst Finland and Sweden are implementing projects for the direct disposal of spent nuclear fuel, France is in an advanced stage of planning. Germany, in contrast, has just set up governance institutions to organize the search for a site and established a dedicated regulator. In all these cases, siting procedures involve public participation, but there are marked differences in the approaches chosen. Our analysis suggests that in Germany there are strong “conflict frames”, but hardly widely accepted instruments to organize inclusive, deliberative processes. Whilst the experience of the Nordic countries showing trust in the institutions and preparedness to delegate negotiation is hardly transferable to Germany, also France's top-down approach cannot serve as a model. Nonetheless useful lessons for policy can be learnt, i.e. inclusive approaches, early access to information, stakeholder involvement and openness to unforeseen results are key conditions for minimising conflicts.
•Factors shaping governance processes in nuclear waste management.•Siting procedures for nuclear waste repositories in four countries.•Analysis of similarities and differences in public participation and veto rights.•Comparison of diverse conditions regarding transparency, trust and participation.•Discussion of possible lessons for policy for the German case.
Chromatin undergoes major remodeling around DNA double-strand breaks (DSB) to promote repair and DNA damage response (DDR) activation. We recently reported a high-resolution map of γH2AX around ...multiple breaks on the human genome, using a new cell-based DSB inducible system. In an attempt to further characterize the chromatin landscape induced around DSBs, we now report the profile of SMC3, a subunit of the cohesin complex, previously characterized as required for repair by homologous recombination. We found that recruitment of cohesin is moderate and restricted to the immediate vicinity of DSBs in human cells. In addition, we show that cohesin controls γH2AX distribution within domains. Indeed, as we reported previously for transcription, cohesin binding antagonizes γH2AX spreading. Remarkably, depletion of cohesin leads to an increase of γH2AX at cohesin-bound genes, associated with a decrease in their expression level after DSB induction. We propose that, in agreement with their function in chromosome architecture, cohesin could also help to isolate active genes from some chromatin remodelling and modifications such as the ones that occur when a DSB is detected on the genome.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper investigates the feasibility of using recycled plastic composed of polypropylene (PP) and high-density polyethylene (HDPE), as a basis for the fabrication of plastic bricks for ...non-structural walls starting from the material characterization. The deformation properties of plastic bricks were evaluated under the application of compression, flexural and traction forces; the thermal analysis of the material was carried out by means of the ignition test, differential scanning calorimeter (DSC) and its water ab-sorption capacity was also tested. Satisfactory results were obtained in the tests carried out; It was found that the compressive strength of the material complies with the requirements of standard specifications for conventional bricks (clay - concrete), and the physicochemical properties of the composite meet specifications of material for use in non-structural walls; which makes it an innovative material with enormous potential for use in the construction sector.
Enteromyxoses are relevant diseases for turbot and gilthead sea bream aquaculture. The myxozoan parasites invade the intestinal mucosa, causing a cachectic syndrome associated with intestinal barrier ...alteration; nonetheless, their pathological impact is different. Turbot infected by Enteromyxum scophthalmi develop more severe intestinal lesions, reaching mortality rates of 100%, whereas in E. leei‐infected gilthead sea bream, the disease progresses slowly, and mortality rates are lower. The mechanisms underlying the different pathogenesis are still unclear. We studied the distribution and expression changes of E‐cadherin, a highly conserved protein of the adherens junctions, in the intestine of both species by immunohistochemistry and quantitative PCR, using the same immunohistochemical protocol and common primers. The regular immunostaining pattern observed in control fish turned into markedly irregular in parasitized turbot, showing an intense immunoreaction at the host–parasite interface. Nevertheless, E‐cadherin gene expression was not significantly modulated in this species. On the contrary, no evident changes in the protein distribution were noticed in gilthead sea bream, whereas a significant gene downregulation occurred in advanced infection. The results contribute to the understanding of the different host–parasite interactions in enteromyxoses. Host and parasite cells appear to establish diverse relationships in these species, which could underlie the different pathological picture.
Cohesin mediates sister chromatid cohesion and 3D genome folding. Two versions of the complex carrying STAG1 or STAG2 coexist in somatic vertebrate cells. STAG2 is commonly mutated in cancer, and ...germline mutations have been identified in cohesinopathy patients. To better understand the underlying pathogenic mechanisms, we report the consequences of Stag2 ablation in mice. STAG2 is largely dispensable in adults, and its tissue-wide inactivation does not lead to tumors but reduces fitness and affects both hematopoiesis and intestinal homeostasis. STAG2 is also dispensable for murine embryonic fibroblasts in vitro. In contrast, Stag2-null embryos die by mid-gestation and show global developmental delay and defective heart morphogenesis, most prominently in structures derived from secondary heart field progenitors. Both decreased proliferation and altered transcription of tissue-specific genes contribute to these defects. Our results provide compelling evidence on cell- and tissue-specific roles of different cohesin complexes and how their dysfunction contributes to disease.
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•MEFs lacking STAG2 show reduced proliferation and mild cohesion defects•Stag2 loss in adult mice reduces fitness but does not increase tumor incidence•Stag2 KO embryos die by E10.5 with global developmental delay and malformed hearts
Cells carry STAG1- and STAG2-cohesin complexes whose functional specificity remains unclear. De Koninck et al. show that Stag2 deletion in mice results in embryonic lethality by mid-gestation. In contrast, STAG2 is not strictly required for viability in cells or adult tissues, and its loss is not sufficient to elicit tumorigenesis.
The structural maintenance of chromosomes (SMC) family is a growing family of chromosomal ATPases. The founding class of SMC protein complexes, condensins, plays a central role in mitotic chromosome ...condensation. We report here a new class of SMC protein complexes containing XSMC1 and XSMC3, Xenopus homologs of yeast Smc1p and Smc3p, respectively. The protein complexes (termed cohesins) exist as two major forms with sedimentation coefficients of 9S and 14S. 9S cohesin is a heterodimer of XSMC1 and XSMC3, whereas 14S cohesin contains three additional subunits. One of them has been identified as a Xenopus homolog of the Schizosaccharomyces pombe Rad21p implicated in DNA repair and the Saccharomyces cerevisiae Scc1p/Mcd1p implicated in sister chromatid cohesion. 14S cohesin binds to interphase chromatin independently of DNA replication and dissociates from it at the onset of mitosis. Immunodepletion of cohesins during interphase causes defects in sister chromatid cohesion in subsequent mitosis, whereas condensation is unaffected. These results suggest that proper assembly of mitotic chromosomes is regulated by two distinct classes of SMC protein complexes, cohesins and condensins.
The cohesin complex organizes the genome-forming dynamic chromatin loops that impact on all DNA-mediated processes. There are two different cohesin complexes in vertebrate somatic cells, carrying the ...STAG1 or STAG2 subunit, and two versions of the regulatory subunit PDS5, PDS5A and PDS5B. Mice deficient for any of the variant subunits are embryonic lethal, which indicates that they are not functionally redundant. However, their specific behavior at the molecular level is not fully understood.
The genome-wide distribution of cohesin provides important information with functional consequences. Here, we have characterized the distribution of cohesin subunits and regulators in mouse embryo fibroblasts (MEFs) either wild type or deficient for cohesin subunits and regulators by chromatin immunoprecipitation and deep sequencing. We identify non-CTCF cohesin-binding sites in addition to the commonly detected CTCF cohesin sites and show that cohesin-STAG2 is the preferred variant at these positions. Moreover, this complex has a more dynamic association with chromatin as judged by fluorescence recovery after photobleaching (FRAP), associates preferentially with WAPL and is more easily extracted from chromatin with salt than cohesin-STAG1. We observe that both PDS5A and PDS5B are exclusively located at cohesin-CTCF positions and that ablation of a single paralog has no noticeable consequences for cohesin distribution while double knocked out cells show decreased accumulation of cohesin at all its binding sites. With the exception of a fraction of cohesin positions in which we find binding of all regulators, including CTCF and WAPL, the presence of NIPBL and PDS5 is mutually exclusive, consistent with our immunoprecipitation analyses in mammalian cell extracts and previous results in yeast.
Our findings support the idea that non-CTCF cohesin-binding sites represent sites of cohesin loading or pausing and are preferentially occupied by the more dynamic cohesin-STAG2. PDS5 proteins redundantly contribute to arrest cohesin at CTCF sites, possibly by preventing binding of NIPBL, but are not essential for this arrest. These results add important insights towards understanding how cohesin regulates genome folding and the specific contributions of the different variants that coexist in the cell.
Aeromonas salmonicida subsp. salmonicida represents one of the major threats in aquaculture, especially in salmonid fish and turbot farming. In order to fight bacterial infections, fish have an ...immune system composed by innate and specific cellular and humoral elements analogous to those present in mammals. However, innate immunity plays a primordial role against bacterial infections in teleost fish. Among these non-specific mechanisms, the production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) pathway and the tumour necrosis factor-alpha (TNFα) produced by mononuclear phagocytes, are two of the main immune effectors to eliminate bacterial pathogens. In this study, the distribution and kinetic of iNOS and TNFα-producing cells of kidney and spleen of turbot experimentally inoculated with A. salmonicida was assessed by immunohistochemistry. In control and challenged fish, individual iNOS+ and TNFα+ cells, showing a similar pattern of distribution, were detected. In challenged fish, the number of immunoreactive cells was significantly increased in the evaluated organs, as well as the melanomacrophage centres showed variable positivity for both antigens. These results indicate that A. salmonicida induced an immune response in challenged turbot, which involved the increase of the activity of iNOS and TNFα in the leukocytic population from kidney and spleen.
•Immunohistochemistry of iNOS and TNFα in Aeromonas salmonicida infection was analyzed.•A. salmonicida infection increased TNFα+ cells in turbot haematopoietic organs.•A. salmonicida infection increased iNOS+ cells in turbot haematopoietic organs.•Kidney was the main source of monocytes/macrophages expressing iNOS and TNFα antigen.•Kidney and spleen play different roles in A. salmonicida infection.
Centromeric protein A (CENP-A) is the epigenetic mark of centromeres. CENP-A replenishment is necessary in each cell cycle to compensate for the dilution associated to DNA replication, but how this ...is achieved mechanistically is largely unknown. We have developed an assay using Xenopus egg extracts that can recapitulate the spatial and temporal specificity of CENP-A deposition observed in human cells, providing us with a robust in vitro system amenable to molecular dissection. Here we show that this deposition depends on Xenopus Holliday junction-recognizing protein (xHJURP), a member of the HJURP/Scm3 family recently identified in yeast and human cells, further supporting the essential role of these chaperones in CENP-A loading. Despite little sequence homology, human HJURP can substitute for xHJURP. We also report that condensin II, but not condensin I, is required for CENP-A assembly and contributes to retention of centromeric CENP-A nucleosomes both in mitosis and interphase. We propose that the chromatin structure imposed by condensin II at centromeres enables CENP-A incorporation initiated by xHJURP.
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