Evidence for the chimeric origin of a pheromone-coding gene in Euplotes raikovi

Ciliates, unique among eukaryotes, evolved two types of nucleus which are distinct in both structure and function. A diploid transcriptionally silent germline micronucleus (MIC) with an orthodox chromosomicstructure coexists in the same cytoplasm with a polyploid transcriptionally active somatic macronucleus (MAC) showing a unique sub-chromosomic structure. This structure is acquired in coincidence with every sexual event, when the ex-conjugant (or ex-autogamic) cell initiates a new life cycle developing a new MAC from a mitotic product of the synkaryon. In spirotrichous ciliates such as Euplotes, the chromosomes of this product undergo impressive phenomena of polytenization, fragmentation in thousands of DNA fragments known as ‘Macronuclear Destined Sequences’ (MDSs), and DNA elimination. Under the guide of noncoding RNA templates synthesized by the old MAC before being destroyed, theseMDSs are assembled into sub-chromosomic (‘gene-size’)DNA molecules which,amplified to thousands of copies, compose the new MAC.The way to a correct MDSassembly may be crossed by errors, with the consequent generation of functional chimeric genes which can stably be integrated and expressed in the MAC genome.One of these chimeric genes came to light by studying the genetic basis of the pheromone-mediated self/not-self recognition mechanism in E. raikovi. The genome of type I cells secreting pheromone Er-1 was found to contain two structurally distinct MAC Er-1 coding genes,both expressed via a mechanism of intron splicing responsible for the synthesis of the Er-1 soluble form and a membrane-bound Er-1 isoform functioning as autocrine pheromone receptor. The sequence of one gene resulted unmistakably homologous throughout its length with the sequences of other members of the E. raikovipheromone gene family. In contrast, the sequence of the second gene resulted unique at level of a 359-bp segment of the 5’ region destined to specify the cytoplasmic domain of the Er-1 membrane-bound isoform. By showing that this segment arises from a wrong assembly of a MDS destined to a 2417-bp gene with no relationship with the signaling pheromone system, we provide additional evidence that the generation of functionally active chimeric genesfrom not-programmed phenomena of somatic MDS recombination is an effective and MIC-independent source of gene variants in the ciliate MAC genome

International human rights bodies and climate litigation: Don't look up?

This article systematically analyses complaints concerning climate change before international human rights bodies. Since 2005, these bodies have been increasingly asked to hear complaints related to climate change but have granted claims of climate applicants only on one occasion. This article therefore considers the inherent limitations of international human rights bodies for the pursuit of climate objectives, as well as avenues to overcome the hurdles facing climate applicants. Based on the evidence we examined, we conclude making some predictions on the role that international human rights bodies might play in future climate litigation

Not too big for its mouth: direct evidence of a macrodasyidan gastrotrich preyed in nature by a dileptid ciliate

Nearly ubiquitous and usually speciose in most aquatic habitats, the meiofaunal-sized gastrotrichs are recognized as an important component of marine and freshwater ecosystems. The common observations that gastrotrichs feed on bacteria, microalgae and biodetritus strongly imply that they play a relevant role in linking the microbial loop to the higher trophic levels. Which are the organisms that in turn prey on gastrotrichs is, however, a substantially unexplored question. Inspecting meiofauna samples collected from shallow sites of the Tyrrhenian coast, we had the chance to spot a wild case of a macrodasyidan gastrotrich predated by a dileptid ciliate. This case is documented here with a set of in-vivo photos, jointly with an unequivocal taxonomic identification of the preyed gastrotrich with Paraturbanella teissieri and a tentative identification of the predator ciliate with Pseudomonilicaryon marinus

Evolution of mating systems in Euplotes

Ciliates control their sexual phenomenon of conjugation (or mating) through a genetic mechanism of mating types, which may either be only two within a species (recalling the duality of sexes in animals), or multiple (recalling self/non-self compatibility systems in plants and fungi). The nearly one hundred species of the most ubiquitously distributed ciliate, Euplotes, all evolved multiple mating types. Based on analyses of Mendelian genetics, these mating types have for long been assumed to be determined by multi-allelic series of genes inherited at a single genetic locus (i.e., the mating-type or mat locus) and responsible for the synthesis of mating type-pecific signaling proteins. The chemical characterization of these signaling proteins (known as pheromones) from an array of Euplotes species has now permitted us to evolve in the study of Euplotes mating types from an approach of Mendelian genetics to an approach of molecular genetics. In this new experimental context, we have cloned and characterized structurally the pheromone (mating-type) gene families of Euplotes species that take different positions in the phylogenetic tree of the genus Euplotes. It appeared that, in accord with the prediction of the Mendelian genetics, early branching species (e.g., E. polaris, E. raikovi and E. nobilii) inherit their mating types at a single multi-allelic locus. However, in disagreement with the prediction of the Mendelian genetics, late branching species (e.g., E. crassus and E. focardii) inherit their mating types at two distinct loci that are likely the result of an event of gene duplication in the germinal (micronuclear) genome. One locus appears to be structurally and functionally homologous with the multi-allelic locus of the early branching species, while the second locus appears to be structurally homologous but functionally divergent

Assessment of myocardial extracellular volume on body computed tomography in breast cancer patients treated with anthracyclines

Background: Cancer treatment with anthracyclines may lead to an increased incidence of cardiac disease due to cardiotoxicity, as they may cause irreversible myocardial fibrosis. So far, the proposed methods for screening patients for cardiotoxicity have led to only limited success, while the analysis of myocardial extracellular volume (mECV) at cardiac magnetic resonance (CMR) has shown promising results, albeit requiring a dedicated exam. Recent studies have found strong correlations between mECV values obtained through computed tomography (CT), and those derived from CMR. Thus, our purpose was to evaluate the feasibility of estimating mECV on thoracic contrast-enhanced CT performed for staging or follow-up in breast cancer patients treated with anthracyclines, and, if feasible, to assess if a rise in mECV is associated with chemotherapy, and persistent over time. Methods: After ethics committee approval, female patients with breast cancer who had undergone at least 2 staging or follow-up CT examinations at our institution, one before and one shortly after the end of chemotherapy including anthracyclines were retrospectively evaluated. Patients without available haematocrit, with artefacts in CT images, or who had undergone radiation therapy of the left breast were excluded. Follow-up CT examinations at longer time intervals were also analysed, when available. mECV was calculated on scans obtained at 1, and 7 min after contrast injection. Results: Thirty-two female patients (aged 57\ub113 years) with pre-treatment haematocrit 38%\ub14%, and ejection fraction 64%\ub16% were analysed. Pre-treatment mECV was 27.0%\ub12.9% at 1 min, and 26.4%\ub13.8% at 7 min, similar to values reported for normal subjects in the literature. Post-treatment mECV (median interval: 89 days after treatment) was 31.1%\ub14.9%, and 30.0%\ub15.1%, respectively, values significantly higher than pre-treatment values at all times (P<0.005). mECV at follow-up (median interval: 135 days after post-treatment CT) was 31.0%\ub14.5%, and 27.7%\ub13.7%, respectively, without significant differences (P>0.548) when compared to post-treatment values. Conclusions: mECV values from contrast-enhanced CT scans could play a role in the assessment of myocardial condition in breast cancer patients undergoing anthracycline-based chemotherapy. CT-derived ECV could be an imaging biomarker for the monitoring of therapy-related cardiotoxicity, allowing for potential secondary prevention of cardiac damage, using data derived from an examination that could be already part of patients\u2019 clinical workflow

A structure-exploiting numbering algorithm for finite elements on extruded meshes, and its performance evaluation in Firedrake

We present a generic algorithm for numbering and then efficiently iterating over the data values attached to an extruded mesh. An extruded mesh is formed by replicating an existing mesh, assumed to be unstructured, to form layers of prismatic cells. Applications of extruded meshes include, but are not limited to, the representation of three-dimensional high aspect ratio domains employed by geophysical finite element simulations. These meshes are structured in the extruded direction. The algorithm presented here exploits this structure to avoid the performance penalty traditionally associated with unstructured meshes. We evaluate the implementation of this algorithm in the Firedrake finite element system on a range of low compute intensity operations which constitute worst cases for data layout performance exploration. The experiments show that having structure along the extruded direction enables the cost of the indirect data accesses to be amortized after 10–20 layers as long as the underlying mesh is well ordered. We characterize the resulting spatial and temporal reuse in a representative set of both continuous-Galerkin and discontinuous-Galerkin discretizations. On meshes with realistic numbers of layers the performance achieved is between 70 and 90 % of a theoretical hardware-specific limit

Malignant osteopetrosis: bone marrow transplantation

A osteopetrose é uma osteopatia hereditária caracterizada pela deficiência na reabsorção óssea que ocorre por disfunção dos osteoclastos. Com o acúmulo de material osteóide que oblitera o canal medular, ocorre hematopoiese extramedular (hepato-esplenomegalia), obliteração dos forames dos nervos cranianos (cegueira, surdez, paralisias faciais), macrocefalia, protusão da fronte, hipertelorismo, exoftalmo, aumento da pressão intracraniana, retardo na erupção dentária, atraso no crescimento, atraso no desenvolvimento neuropsicomotor, e a morte ocorre precocemente nos primeiros anos de vida. A única alternativa terapêutica curativa é o transplante de medula óssea (TMO) de doador HLA idêntico, pois restabelece a hematopoiese e a função monócito-macrófago, com melhora das lesões ósseas e anormalidades hematopoiéticas, embora não reverta as alterações sensoriais já instaladas. Os autores relatam casos de duas crianças portadoras de osteopetrose maligna submetidas ao transplante de medula óssea com sucesso. A primeira encontra-se no dia +1260 do TMO, com melhora evidente da radiologia esquelética, sem progressão das deficiências neurológicas que apresentava, e com biópsia óssea sem sinais de osteopetrose. O segundo paciente encontra-se no dia + 700, com sinais de reabsorção óssea e sem progressão dos danos neurológicos. Os autores chamam a atenção para a necessidade de diagnóstico precoce da osteopetrose e o rápido encaminhamento para o transplante de medula óssea antes da instalação de seqüelas neurológicas definitivas.Osteopetrosis is an inherited disorder characterized by the inability to reabsorb and remodel bone due to osteoclast dysfunction. The encroachment by bone and mineralized cartilage of the medullary cavities leads to extramedullary hematopoiesis (hepatosplenomegaly) and cranial-nerve foramina leads to blindness, auditory nerve damage, and occulomotor and facial nerve palsies. Defective bone re-absorption also leads to macrocephaly, frontal bossing, hypertelorism, exophthalmos, increased intracranial pressure, retarded tooth eruption, retarded linear growth and psychomotor delay. Death occurs within the first years of life. The only curative therapy is allogeneic bone marrow transplantation with a HLA-identical donor, which restores hematopoiesis, monocyte-macrophage function and bone recovery, but there is no sensorial deficit restoration once present. The authors report two cases of allogeneic bone marrow transplant for infantile malignant osteopetrosis. The first child, on day 1260 after bone marrow transplantation (BMT), showed radiologic bone recovery and no progression of neurological deficits with a bone biopsy showing no signs of osteopetrosis. The second child showed signs of bone re-absorption and no progression of neurological deficits on day 700. The authors emphasize the importance of early diagnosis of osteopetrosis and the necessity of bone marrow transplantation before neurological deficits have begun

A combination of gemcitabine and 5-fluorouracil in advanced pancreatic cancer, a report from the Italian Group for the Study of Digestive Tract Cancer (GISCAD)

In a randomized clinical trial, gemcitabine (GEM) was more effective than 5-fluorouracil (5-FU) in advanced pancreatic cancer patients. GEM and 5-FU have different mechanisms of action and their combination, from a theoretical point of view, could result in a higher activity. To test activity and feasibility of such a combination, a multi-institutional phase II study was initiated in November 1996 by the Italian Group for the study of Digestive Tract Cancer (GISCAD). Primary objectives of this study were to determine the activity in terms of response rate and clinical benefit, while the secondary objective was toxicity. According to the optimal two-stage phase II design, 54 patients were enrolled. Schedule was: GEM 1000 mg m(-2) intravenous (i.v.), and 5-FU 600 mg m(-2) bolus i.v. weekly for 3 weeks out of every 4. All the 54 patients were symptomatic (pain, weight loss, dyspepsia). A clinical benefit was obtained in 28 patients (51\%) (95\% confidence interval (CI) 38-64\%). Two patients achieved a partial response and 34 a stable disease. Median survival for all the patients was 7 months. Side-effects were mild: no gastrointestinal or haematological grade 3-4 toxicity (WHO) were recorded. We observed only six episodes of grade 2 (WHO) leukopenia and seven episodes of thrombocytopenia. Although the non-randomized design of this study suggests caution in the interpretation of these data, in consideration of the low incidence of toxicity and the favourable results obtained in terms of clinical benefit, it may be worthwhile to test more active schedules of 5-FU (continuous infusion) in combination with gemcitabine