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

Evidence for Gene Duplication and Allelic Codominance (not Hierarchical Dominance) at the Mating-Type Locus of the Ciliate, Euplotes crassus.

The high-multiple mating system of Euplotes crassus is known to be controlled by multiple alleles segregating at a single locus and manifesting relationships of hierarchical dominance, so that heterozygous cells would produce a single mating-type substance (pheromone). In strain L-2D, now known to be homozygous at the mating-type locus, we previously identified two pheromones (Ec-α and Ec-1) characterized by significant variations in their amino acid sequences and structure of their macronuclear coding genes. In this study, pheromones and macronuclear coding genes have been analyzed in strain POR-73 characterized by a heterozygous genotype and strong mating compatibility with L-2D strain. It was found that POR-73 cells contain three distinct pheromone coding genes and, accordingly, secrete three distinct pheromones. One pheromone revealed structural identity in amino acid sequence and macronuclear coding gene to the Ec-α pheromone of L-2D cells. The other two pheromones were shown to be new and were designated Ec-2 and Ec-3 to denote their structural homology with the Ec-1 pheromone of L-2D cells. We interpreted these results as evidence of a phenomenon of gene duplication at the E. crassus mating-type locus, and lack of hierarchical dominance in the expression of the macronuclear pheromone genes in cells with heterozygous genotypes

The quest for a molecular capsule assembled via halogen bonds

A halogen-bonded capsule is obtained via directed assembly of a rigid tetra(3-pyridyl) cavitand and a flexible tetra(4-iodotetrafluorophenyl) calix[4]arene. The pyridyl nitrogen atoms from one cavitand molecule interact with the iodine atoms of a single calixarene molecule through short and directional I…N halogen bonds. The flexibility of the ethylenedioxy moieties on the calixarene platform results in positional flexibility of the iodotetrafluorobenzene sites which, coupled with a supramolecular chelating effect, allow for an effective partner-induced geometric fitting between four nitrogen atoms on the cavitand and four iodine atoms on the calixarene

Averaging bias correction for the future space-borne methane IPDA lidar mission MERLIN

The CNES (French Space Agency) and DLR (German Space Agency) project MERLIN is a future integrated path differential absorption (IPDA) lidar satellite mission that aims at measuring methane dry-air mixing ratio columns (XCH4) in order to improve surface flux estimates of this key greenhouse gas. To reach a 1&thinsp;% relative random error on XCH4 measurements, MERLIN signal processing performs an averaging of data over 50&thinsp;km along the satellite trajectory. This article discusses how to process this horizontal averaging in order to avoid the bias caused by the non-linearity of the measurement equation and measurements affected by random noise and horizontal geophysical variability. Three averaging schemes are presented: averaging of columns of XCH4, averaging of columns of differential absorption optical depth (DAOD) and averaging of signals. The three schemes are affected both by statistical and geophysical biases that are discussed and compared, and correction algorithms are developed for the three schemes. These algorithms are tested and their biases are compared on modelled scenes from real satellite data. To achieve the accuracy requirements that are limited to 0.2&thinsp;% relative systematic error (for a reference value of 1780&thinsp;ppb), we recommend performing the averaging of signals corrected from the statistical bias due to the measurement noise and from the geophysical bias mainly due to variations of methane optical depth and surface reflectivity along the averaging track. The proposed method is compliant with the mission relative systematic error requirements dedicated to averaging algorithms of 0.06&thinsp;% (±1&thinsp;ppb for XCH4 = 1780 ppb) for all tested scenes and all tested ground reflectivity values.</p

Effects of adjunctive eslicarbazepine acetate on neurocognitive functioning in children with refractory focal-onset seizures.

Abstract Purpose This was a phase-II, randomized, double-blind (DB), placebo-controlled study aimed to evaluate neurocognitive effects of eslicarbazepine acetate (ESL) as adjunctive therapy in pediatric patients with refractory focal-onset seizures (FOS). Methods Children (6–16 years old) with FOS were randomized (2:1) to ESL or placebo. Treatment started at 10 mg/kg/day, was up-titrated up to 30 mg/kg/day (target dose), and maintained for 8 weeks, followed by one-year open-label follow-up. The primary endpoint was change from baseline to the end of maintenance period in the composite Power of Attention assessed with the Cognitive Drug Research (CDR) system. Behavioral and emotional functioning and quality of life (QOL), secondary endpoints, were assessed with Child Health Questionnaire-Parent Form 50 (CHQ-PF50), Child Behavior Checklist (CBCL), and Raven's Standard Progressive Matrices (SPM). Efficacy was evaluated through changes in standardized seizure frequency (SF), responder rate, and proportion of seizure-free patients. Safety was evaluated by the incidence of treatment-emergent adverse events (TEAEs). Results One hundred and twenty-three patients were randomized. A noninferiority analysis failed to reject the null hypothesis that the change from baseline in the Power of Attention score in the ESL group was at least 121 ms inferior to the placebo group for all age groups. The CDR scores showed no differences between placebo and ESL in Power of Attention (1868.0 vs 1759.5), Continuity of Attention (1.136 vs − 1.786), Quality of Working Memory (− 0.023 vs − 0.024), and Speed of Memory (− 263.4 vs − 249.6). Nonsignificant differences between placebo and ESL were seen for CHQ-PF50, CBCL scores, and Raven's SPM. Episodic Memory Index showed significant negative effect on ESL. Efficacy results favored the ESL group (SF least square [LS] means 1.98 vs 4.29). The TEAEs had a similar incidence between treatment groups (41.0% vs 47.5%). Conclusions Overall ESL did not produce statistically significant effects on neurocognitive and behavioral functioning in patients with epilepsy aged 6 to 16 years. Additionally, ESL was effective in reducing seizure frequency and was well-tolerated

Reemergence of Strongyloidiasis, Northern Italy

Strongyloidiasis is a helminth infection caused by Strongyloides stercoralis, a nematode ubiquitous in tropical and subtropical countries and occasionally reported in temperate countries, including Italy (1). Sources of infection are filariform strongyloid larvae present in soil contaminated by infected feces; the larvae penetrate through the skin of a human host. After the first life cycle, a process of autoinfection begins, which persists indefinitely in the host if the infection is not effectively treated. The infection can remain totally asymptomatic for many years or forever or cause cutaneous (itching and rash), abdominal (epigastric pain, pseudoappendicitis, diarrhea), respiratory (cough, recurrent asthma), and systemic (weight loss, cachexia) symptoms that can be enervating. More importantly, when host immunity is impaired because of a concurrent disease or immunosuppressive therapy (including corticosteroids, sometimes used to treat symptoms of the unrecognized infection or the concurrent eosinophilia), disseminated strongyloidiasis may occur (2\u20134), causing a massive and almost invariably fatal invasion of virtually all organs and tissues by filariform larvae and even adult worms (Figure), often combined with bacterial superinfection. This complication is believed to be rare but is probably underestimated because of the extreme variability of the clinical presentation. Although strongyloidiasis can be suspected in the presence of symptoms or eosinophilia (which is frequent but not mandatory), the low sensitivity of direct diagnostic methods often lets the disease go unrecognized (5\u20137). By far the most sensitive diagnostic tools are serologic tests: sensitivity and specificity of indirect fluorescent antibody test (IFAT) (in-house produced IFAT) are 97.4% and 97.9%, respectively, at a dilution >1/20, and 70.5% and 99.8% at a dilution >1/80 (6). A suspected case is defined by a positive antibody titer >20 (IFAT); a case is confirmed by a positive direct test result (culture in agar being the most sensitive direct technique) or by a positive antibody titer >80 (6). Despite some anecdotal reports on the presence of strongyloidiasis in Italy (1,6), reliable information about the real prevalence of the infection is lacking. After seeing several patients affected by the disease, 1 of whom died because of dissemination (Z. Bisoffi, unpub. data), we decided to carry out a preliminary rapid assessment of the extent of the problem in elderly patients with eosinophilia. During a 4-month period, from February through May 2008, every patient born in 1940 or earlier who came to the clinical laboratories of 2 contiguous health districts in northern Italy (Mantova, Lombardy Region, and Legnago, Veneto Region) for a diagnostic blood test (hematocrit and leukocyte count/formula) for whatever reason and having a eosinophil count >500 cells/\u3bcL was asked to join the study. This study was the pilot phase of a larger, multicentered study, which obtained formal approval from the Ethical Committee of Sacro Cuore Hospital of Negrar, Verona. Informed consent was required of each patient. Of the 132 patients eligible for inclusion (mean age 76.4 years, range 68\u201390 years, male:female ratio 1.6), none refused to give informed consent. Serum specimens were subjected to the IFAT for S. stercoralis at the Sacro Cuore Hospital Centre for Tropical Diseases. Unexpectedly, we found that 37 (28%) of 132 patients were positive, with titers ranging between 20 and >320 (and >80 in most cases). However, caution should be exercised in interpreting the results because the patients may not be representative of the general population. Moreover, our results are based on an indirect (although highly sensitive and specific) test. Because the reported cases involve only a few patients every year (of whom some are anecdotally reported as dying from the infection, usually unpublished), we suspect that most strongyloidiasis cases remain undetected. If relevant transmission still exists in the area, it is unknown but is unlikely because of the improvement of hygienic conditions in the past 5 decades. Reports of the infection in children or young adults with no travel history outside Italy are lacking. Strongyloidiasis in the elderly is therefore most likely to result from an infection that occurred much earlier in life, either in infancy or at a young age, while walking or working barefoot in agricultural fields. The long persistence is the consequence of the autoinfection cycle typical of this parasite as described above. The result is an important and unrecognized public health problem affecting the geriatric population of northern Italy. These preliminary results confirm the need for the already planned, multicentered study involving a larger sample and a wider geographic area

Non-neuronal TRPA1 encodes mechanical allodynia associated with neurogenic inflammation and partial nerve injury in rats

Background and purpose: The pro-algesic transient receptor potential ankyrin 1 (TRPA1) channel, expressed by a subpopulation of primary sensory neurons, has been implicated in various pain models in mice. However, evidence in rats indicates that TRPA1 conveys nociceptive signals elicited by channel activators, but not those associated with tissue inflammation or nerve injury. Here, in rats, we explored the TRPA1 role in mechanical allodynia associated with stimulation of peptidergic primary sensory neurons (neurogenic inflammation) and moderate (partial sciatic nerve ligation, pSNL) or severe (chronic constriction injury, CCI) sciatic nerve injury. Experimental approach: Acute nociception and mechanical hypersensitivity associated with neurogenic inflammation and sciatic nerve injury (pSNL and CCI) were investigated in rats with TRPA1 pharmacological antagonism or genetic silencing. TRPA1 presence and function were analysed in cultured rat Schwann cells. Key results: Hind paw mechanical allodynia (HPMA), but not acute nociception, evoked by local injection of capsaicin or allyl isothiocyanate, the TRP vanilloid 1 (TRPV1) or the TRPA1 activators was mediated by CGRP released from peripheral sensory nerve terminals. CGRP-evoked HPMA was sustained by a ROS-dependent TRPA1 activation, probably in Schwann cells. HPMA evoked by pSNL, but not that evoked by CCI, was mediated by ROS and TRPA1 without the involvement of CGRP. Conclusions and implications: As found in mice, TRPA1 mediates mechanical allodynia associated with neurogenic inflammation and moderate nerve injury in rats. The channel contribution to mechanical hypersensitivity is a common feature in rodents and might be explored in humans