Malacoraja obscura, Brazilian Soft Skate

The Brazilian Soft Skate (Malacoraja obscura) is a small (to 68 cm total length) skate that has a very restricted range in the Southwest Atlantic Ocean from central Espírito Santo and northern Rio de Janeiro states in Brazil. It inhabits the continental slope at depths of 808-1,105 m. Although Extent of Occurrence cannot be calculated because the species is only known from two localities, it is suspected to be about 30,000 km2 (if the species is assumed to inhabit the steep slope between the two known localities). Area of Occupancy is estimated at 3,680 km2 (calculated based on including the known depth range of the species between the two known localities). This skate inhabits waters currently beyond the reach of fisheries, and there are no other known threats. Therefore, the population is suspected to be stable and the Brazilian Soft Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Bathyraja scaphiops, Cuphead Skate

The Cuphead Skate (Bathyraja scaphiops) is a medium-sized (to 117 cm total length) skate that occurs in the Southwest Atlantic from off Rio Grande do Sul, Brazil to Tierra del Fuego, Argentina and the Falkland Islands (Malvinas). It inhabits continental and insular shelves and slopes at depths of 30?925 m. It is targeted or captured as utilized bycatch in demersal trawl fisheries, including the southern Brazil otter trawl fishery, the Patagonian scallop and hake fisheries, and the Falkland Islands (Malvinas) targeted multi-species skate fishery. At the northern extent of its range in southern Brazil, it is captured in the otter trawl fishery which is intense; reductions in the population are suspected there but there are no data. In the Argentina-Uruguay Common Fishing Zone (AUCFZ), this species was captured frequently in commercial trawls between 1984 and 2009. On the shelf edge off Argentina between Buenos Aires and northern Santa Cruz, this species was present in 9% of research trawls in the area trawled by the Patagonian scallop fishery in 2010. In the Falkland Islands (Malvinas), this species made up an average of 3.5% of the catch in the multi-species skate fishery between 1993 and 2013, with no clear trend in catch-per-unit-effort over that time frame. Overall, although this species is subjected to substantial fishing pressure, it has remained common in catches and it may have refuge over rough substrates that are untrawlable. Although fisheries are likely leading to some reduction in population size, the level is not suspected to approach the thresholds for a threatened assessment. Therefore, the Cuphead Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Pompert, J.. No especifíca;Fil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Dipturus leptocaudus, Thintail Skate

The Thintail Skate (Dipturus leptocaudus) is a medium-sized (to 88 cm total length) skate that occurs in the Southwest Atlantic from Santa Catarina, Brazil to Uruguay (and possibly Argentina). It inhabits the continental shelf and upper slope at depths of 10–550 m. It is captured in commercial deep-water trawl, longline, and gillnet fisheries, which operate throughout its known range. Little information is available regarding the amount of catches due to identification issues. Dipturus spp. were the most abundant elasmobranchs caught in the monkfish (Lophius gastrophysus) deep-water gillnet fishery off southern Brazil, which intensified in the 2000s. These industrial gillnet fisheries often also target skates, and have led to declines in other ecologically similar species such as angel sharks (Squatina spp.). Dipturus spp. were shown to be highly vulnerable to such fisheries in a productivity-susceptibility analysis. There are also deep-water trawlers operating in the area targeting shrimp and squid, which are intense. Overall, due to the presence of intense and inadequately managed trawl fisheries that operate throughout its range, it is suspected that the Thintail Skate has undergone a population reduction of 30–49% over the past three generations (21 years), and it is assessed as Vulnerable A2d.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Pompert, J.. Georgia Seafoods; Países BajosFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Squatina argentina, argentine angelshark

The Argentine Angelshark (Squatina argentina) is a small (to 138 cm total length) demersal shark species that occurs in waters in the Southwest Atlantic from Santa Catarina, Brazil, south to Buenos Aires, Argentina. This species inhabits sandy substrates at depths of 51-320 m. The species has a relatively slow life history, giving birth to 7-11 pups with a biennial or possibly triennial reproductive cycle. The Argentine Angelshark is targeted and/or caught as bycatch in demersal trawl, gillnet, and longline fisheries, and is sold and utilized for human consumption (although angel sharks are protected in Brazil). Angel sharks are notoriously difficult to identify, and catches are typically reported at the generic level and therefore include at least three species that are native to the region (the Argentine Angelshark, the Hidden Angelshark (S. occulta), and the Angular Angelshark (S. guggenheim)). Declines in CPUE during research trawls in southern Brazil indicate that the population declined substantially in the mid-late 1990s. Further research data corroborates this, indicating the equivalent of a reduction of more than 90% over three generation lengths (46.5 years). There is also heavy fishing pressure in Uruguay and Argentina, where the Argentine Angelshark is caught alongside the Hidden Angelshark and the Angular Angelshark. Landings data indicate a reduction of angel sharks in the Argentinean-Uruguayan Common Fishing Zone of over 70% over three generations, and datasets further south in Argentina indicate a reduction of over 90% over a similar timeframe (although these landings likely consist mostly of Angular Angelshark). Due to heavy fishing pressure across its range, reported declines in landings and research surveys, and the species' low productivity, it is inferred that this species has undergone, on balance, a population reduction of at least 80% over the past three generations (46.5 years). Therefore, the Argentine Angelshark is listed as Critically Endangered A2bd. Strict regulations for limits to fisheries catch are needed, as is the identification and protection of critical habitat.Fil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Awruch, Cynthia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Faria, V.. Universidade Federal Do Ceara; BrasilFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Arylmethylamino steroids as antiparasitic agents

In search of antiparasitic agents, we here identify arylmethylamino steroids as potent compounds and characterize more than 60 derivatives. The lead compound 1o is fast acting and highly active against intraerythrocytic stages of chloroquine-sensitive and resistant Plasmodium falciparum parasites (IC50 1–5?nM) as well as against gametocytes. In P. berghei-infected mice, oral administration of 1o drastically reduces parasitaemia and cures the animals. Furthermore, 1o efficiently blocks parasite transmission from mice to mosquitoes. The steroid compounds show low cytotoxicity in mammalian cells and do not induce acute toxicity symptoms in mice. Moreover, 1o has a remarkable activity against the blood-feeding trematode parasite Schistosoma mansoni. The steroid and the hydroxyarylmethylamino moieties are essential for antimalarial activity supporting a chelate-based quinone methide mechanism involving metal or haem bioactivation. This study identifies chemical scaffolds that are rapidly internalized into blood-feeding parasites

Squatina occulta, Hidden Angelshark

The Hidden Angelshark (Squatina occulta) is a medium-sized shark (to 160 cm total length) endemic to the Southwest Atlantic inhabiting waters from Rio de Janeiro, Brazil, to Buenos Aires Province, Argentina and likely further south to the northern Patagonia-Argentine region. It is mainly found on the continental shelf at depths of 10-150 m, but has been found at depths to 350 m. The species' low reproductive potential (litter size of 4-10 and a possible three-to-five-year female breeding cycle) together with its susceptibility to capture in both trawl and gillnet gear makes it highly susceptible to population depletion. Angel sharks are heavily fished in southern Brazil and significant reductions have been documented there. In the period from 1988 to 2002, on the continental shelf of southern Brazil, the abundance of Squatina species was reduced by approximately 85%, and benthic trawl fishing continued to intensively exploit this population in more recent years. In the same region, scientific fishing cruises conducted between 1986 to 2001 using bottom trawls revealed that the frequency of occurrence and CPUE (in kg/hour and number of individuals/hour) of this species was reduced by 80% confirming trends observed in commercial fisheries. In Argentina, trawl catches of Squatina underwent a reduction of 58% in the years 1992-1998, showing a continuing negative trend since then. These are the equivalent of a >99% reduction over three generation lengths (46.5 years), however there may be other areas within its range where fishing intensity is not as high. The catch and trade of this species has been banned in Brazil since 2004, but it is still targeted illegally and caught as bycatch and sold in markets. Given the species' relatively low productivity, the presence of intensive fisheries throughout the species' range, and the level of localized reductions reported, the Hidden Angelshark is inferred to have undergone a population reduction of over 80% over three generation lengths (46.5 years) across its range, and is therefore assessed as Critically Endangered A2bd.Fil: Awruch, C. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Faria, V.. Universidade Federal Do Ceara; BrasilFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Properties of projectile-fragments in the 40^{40}Ar + 27^{27}Al reaction at 44 A MeV. Comparison with a multisequential decay model

GANIL-EXPResults on projectile fragment–fragment coincidences in the forward direction and for the reaction 40Ar + 27Al at 44 A MeV are presented and compared with the predictions of two different entrance channel models, a two-body and a three-body mechanism both followed by a binary multisequential decay including fission. This analysis shows that many features of the projectile decay products are well accounted for by the binary multisequential decay model. However the results depend critically upon the initial masses and excitation energies of the primary projectile fragments. In this respect, the three-body approach underestimates the excitation energy imparted to the primary fragments whereas the two-body scenario overestimates it. The present data put strong constraints on the initial excitation energy imparted to the primary fragments which appears to be intermediate between the predictions of the two models

Recent Duplication and Functional Divergence in Parasitic Nematode Levamisole-Sensitive Acetylcholine Receptors

Helminth parasites rely on fast-synaptic transmission in their neuromusculature to experience the outside world and respond to it. Acetylcholine plays a pivotal role in this and its receptors are targeted by a wide variety of both natural and synthetic compounds used in human health and for the control of parasitic disease. The model, Caenorhabditis elegans is characterized by a large number of acetylcholine receptor subunit genes, a feature shared across the nematodes. This dynamic family is characterized by both gene duplication and loss between species. The pentameric levamisole-sensitive acetylcholine receptor has been characterized from C. elegans, comprised of five different subunits. More recently, cognate receptors have been reconstituted from multiple parasitic nematodes that are found to vary in subunit composition. In order to understand the implications of receptor composition change and the origins of potentially novel drug targets, we investigated a specific example of subunit duplication based on analysis of genome data for 25 species from the 50 helminth genome initiative. We found multiple independent duplications of the unc-29, acetylcholine receptor subunit, where codon substitution rate analysis identified positive, directional selection acting on amino acid positions associated with subunit assembly. Characterization of four gene copies from a model parasitic nematode, Haemonchus contortus, demonstrated that each copy has acquired unique functional characteristics based on phenotype rescue of transgenic C. elegans and electrophysiology of receptors reconstituted in Xenopus oocytes. We found evidence that a specific incompatibility has evolved for two subunits co-expressed in muscle. We demonstrated that functional divergence of acetylcholine receptors, driven by directional selection, can occur more rapidly than previously thought and may be mediated by alteration of receptor assembly. This phenomenon is common among the clade V parasitic nematodes and this work provides a foundation for understanding the broader context of changing anthelmintic drug targets across the parasitic nematodes

Atlantoraja castelnaui, Spotback Skate

The Spotback Skate (Atlantoraja castelnaui) is a medium-sized (to 147 cm total length) skate that occurs in the Southwest Atlantic from Rio de Janeiro, Brazil, to Buenos Aires, Argentina. It inhabits the continental shelf and upper slope from inshore to 300 m depth. It is captured in intense and largely unmanaged demersal trawl fisheries throughout its geographic range. Two lines of evidence indicate a population reduction. First, in Santa Catarina State, Brazil, catch-per-unit-effort (CPUE) declined by an estimated 54% between 1974 and 1981. Second, a 75% decline in CPUE was estimated from 1994 to 1999 in Rio Grande do Sul, Brazil. Both declines are consistent with a population reduction of >99% over three generation lengths (48 years). This large skate has a slow life history, and many skates with similar characteristics have undergone severe population reductions and face increased extinction risk. It is highly susceptible to exploitation and does not have any refuge from fishing at depth. Overall, due to declining abundance from intense and largely unmanaged fishing through most of its range combined with its large size and presumed late age-at-maturity (and therefore high sensitivity to fishing pressure), it is suspected that the Spotback Skate has undergone a population reduction of >80% over the past three generation lengths (48 years), and it is assessed as Critically Endangered A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Faria, V.. Universidade Federal Do Ceara; BrasilFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

In Silico Mining for Antimalarial Structure-Activity Knowledge and Discovery of Novel Antimalarial Curcuminoids.

Malaria is a parasitic tropical disease that kills around 600,000 patients every year. The emergence of resistant Plasmodium falciparum parasites to artemisinin-based combination therapies (ACTs) represents a significant public health threat, indicating the urgent need for new effective compounds to reverse ACT resistance and cure the disease. For this, extensive curation and homogenization of experimental anti-Plasmodium screening data from both in-house and ChEMBL sources were conducted. As a result, a coherent strategy was established that allowed compiling coherent training sets that associate compound structures to the respective antimalarial activity measurements. Seventeen of these training sets led to the successful generation of classification models discriminating whether a compound has a significant probability to be active under the specific conditions of the antimalarial test associated with each set. These models were used in consensus prediction of the most likely active from a series of curcuminoids available in-house. Positive predictions together with a few predicted as inactive were then submitted to experimental in vitro antimalarial testing. A large majority from predicted compounds showed antimalarial activity, but not those predicted as inactive, thus experimentally validating the in silico screening approach. The herein proposed consensus machine learning approach showed its potential to reduce the cost and duration of antimalarial drug discovery