Pathogenesis of an experimental mycobacteriosis in an apple snail

In this work, we aimed at investigating cell and tissue responses of the apple snail Pomacea canaliculata, following the inoculation of the zoonotic pathogen Mycobacterium marinum. Different doses were tested (10, 20, 65, and 100 M CFU) and the mortality rate was negligible. The histopathogenesis was followed at 4, 9, and 28 days after inoculation. Overt histopathological lesions were consistently observed after the two largest doses only. In the lung, marked hemocyte aggregations, including intravascular nodule formation, were observed within the large blood veins that run along the floor and roof of this organ. Hemocyte aggregations were found occluding many of the radial sinuses supplying the respiratory lamina. Acid-fast bacilli were contained in the different hemocyte aggregations. In addition, hemocytes were observed infiltrating the storage tissue, which makes up most of the lung wall, and the connective tissue of the mantle edge. Additionally, signs of degradation in the storage tissue were observed in the lung wall on day 28. In the kidney, nodules were formed associated with the constitutive hemocyte islets and with the subpallial hemocoelic space, in whose hemocytes the acid-fast structures were found. Electron microscopy analysis revealed the presence of bacteria-containing phagosomes within hemocytes located in the surface zone of the islets. Additionally, electron-dense spheroidal structures, which are likely remnants of digested mycobacteria, were observed in close proximity to the hemocytes’ nuclei. The size attained by the hemocyte nodules varied during the observation period, but there was no clear dependence on dose or time after inoculation. Nodules were also formed subpallially. Some of these nodules showed 2–3 layers with different cellular composition, suggesting they may also form through successive waves of circulating cells reaching them. Nodular cores, including those formed intravascularly in the lung, would exhibit signs of hemocyte dedifferentiation, possibly proliferation, and death. Hemocyte congestion was observed in the hemocoelic spaces surrounding the pallial ends of the renal crypts, and the renal crypts themselves showed de-epithelization, particularly on day 28. The diverse cellular responses of P. canaliculata to M. marinum inoculation and the high resilience of this snail to the pathogen make it a suitable species for studying mycobacterial infections and their effects on cellular and physiological processes

Estudio integral de los efectos del cadmio en la biología reproductiva del bioindicador Pomacea canaliculata

Pomacea canaliculata es un gasterópodo dulceacuícola que ha ganado notoriedad como organismo indicador de diferentes contaminantes ambientales, y en particular, por su “tolerancia” a elementos potencialmente tóxicos para los ecosistemas y la salud humana. Hemos aprendido que esta especie es capaz de tolerar concentraciones de mercurio y arsénico disueltos en agua, varios órdenes de magnitud por arriba de lo permito en el agua de bebida para consumo humano, gracias a su tejido renal y las células de la glándula digestiva junto a sus simbiontes intracelulares.Facultad de Ciencias Médica

Estudio integral de los efectos del cadmio en la biología reproductiva del bioindicador Pomacea canaliculata

Pomacea canaliculata es un gasterópodo dulceacuícola que ha ganado notoriedad como organismo indicador de diferentes contaminantes ambientales, y en particular, por su “tolerancia” a elementos potencialmente tóxicos para los ecosistemas y la salud humana. Hemos aprendido que esta especie es capaz de tolerar concentraciones de mercurio y arsénico disueltos en agua, varios órdenes de magnitud por arriba de lo permito en el agua de bebida para consumo humano, gracias a su tejido renal y las células de la glándula digestiva junto a sus simbiontes intracelulares.Facultad de Ciencias Médica

Estudio integral de los efectos del cadmio en la biología reproductiva del bioindicador Pomacea canaliculata

Pomacea canaliculata es un gasterópodo dulceacuícola que ha ganado notoriedad como organismo indicador de diferentes contaminantes ambientales, y en particular, por su “tolerancia” a elementos potencialmente tóxicos para los ecosistemas y la salud humana. Hemos aprendido que esta especie es capaz de tolerar concentraciones de mercurio y arsénico disueltos en agua, varios órdenes de magnitud por arriba de lo permito en el agua de bebida para consumo humano, gracias a su tejido renal y las células de la glándula digestiva junto a sus simbiontes intracelulares.Facultad de Ciencias Médica

Supergravity and a Bogomol'nyi Bound in Three Dimensions

We discuss the $2+1$ dimensional Abelian Higgs model coupled to $N=2$ supergravity. We construct the supercharge algebra and, from it, we show that the mass of classical static solutions is bounded from below by the topological charge. As it happens in the global case, half of the supersymmetry is broken when the bound is attained and Bogomol'nyi equations, resulting from the unbroken supersymmetry, hold. These equations, which correspond to gravitating vortices, include a first order self-duality equation whose integrability condition reproduces the Einstein equation.Comment: 25 pages, latex, no figure

Exact solutions of closed string theory

We review explicitly known exact $D=4$ solutions with Minkowski signature in closed bosonic string theory. Classical string solutions with space-time interpretation are represented by conformal sigma models. Two large (intersecting) classes of solutions are described by gauged WZW models and `chiral null models' (models with conserved chiral null current). The latter class includes plane-wave type backgrounds (admitting a covariantly constant null Killing vector) and backgrounds with two null Killing vectors (e.g., fundamental string solution). $D>4$ chiral null models describe some exact $D=4$ solutions with electromagnetic fields, for example, extreme electric black holes, charged fundamental strings and their generalisations. In addition, there exists a class of conformal models representing axially symmetric stationary magnetic flux tube backgrounds (including, in particular, the dilatonic Melvin solution). In contrast to spherically symmetric chiral null models for which the corresponding conformal field theory is not known explicitly, the magnetic flux tube models (together with some non-semisimple WZW models) are among the first examples of solvable unitary conformal string models with non-trivial $D=4$ curved space-time interpretation. For these models one is able to express the quantum hamiltonian in terms of free fields and to find explicitly the physical spectrum and string partition function.Comment: 50 pages, harvma

First external quality assurance program for bloodstream Real-Time PCR monitoring of treatment response in clinical trials of Chagas disease

Real-Time PCR (qPCR) testing is recommended as both a diagnostic and outcome measurement of etiological treatment in clinical practice and clinical trials of Chagas disease (CD), but no external quality assurance (EQA) program provides performance assessment of the assays in use. We implemented an EQA system to evaluate the performance of molecular biology laboratories involved in qPCR based follow-up in clinical trials of CD. An EQA program was devised for three clinical trials of CD: the E1224 (NCT01489228), a pro-drug of ravuconazole; the Sampling Study (NCT01678599), that used benznidazole, both conducted in Bolivia; and the CHAGASAZOL (NCT01162967), that tested posaconazole, conducted in Spain. Four proficiency testing panels containing negative controls and seronegative blood samples spiked with 1, 10 and 100 parasite equivalents (par. eq.)/mL of four Trypanosoma cruzi stocks, were sent from the Core Lab in Argentina to the participating laboratories located in Bolivia and Spain. Panels were analyzed simultaneously, blinded to sample allocation, at 4-month intervals. In addition, 302 random blood samples from both trials carried out in Bolivia were sent to Core Lab for retesting analysis. The analysis of proficiency testing panels gave 100% of accordance (within laboratory agreement) and concordance (between laboratory agreement) for all T. cruzi stocks at 100 par. eq./mL; whereas their values ranged from 71 to 100% and from 62 to 100% at 1 and 10 par. eq./mL, respectively, depending on the T. cruzi stock. The results obtained after twelve months of preparation confirmed the stability of blood samples in guanidine-EDTA buffer. No significant differences were found between qPCR results from Bolivian laboratory and Core Lab for retested clinical samples. This EQA program for qPCR analysis of CD patient samples may significantly contribute to ensuring the quality of laboratory data generated in clinical trials and molecular diagnostics laboratories of CD

Signatures of divergence, invasiveness, and terrestrialization revealed by four apple snail genomes

The family Ampullariidae includes both aquatic and amphibious apple snails. They are an emerging model for evolutionary studies due to the high diversity, ancient history, and wide geographical distribution. Insight into drivers of ampullariid evolution is hampered, however, by the lack of genomic resources. Here, we report the genomes of four ampullariids spanning the Old World (Lanistes nyassanus) and New World (Pomacea canaliculata, P. maculata, and Marisa cornuarietis) clades. The ampullariid genomes have conserved ancient bilaterial karyotype features and a novel Hox gene cluster rearrangement, making them valuable in comparative genomic studies. They have expanded gene families related to environmental sensing and cellulose digestion, which may have facilitated some ampullarids to become notorious invasive pests. In the amphibious Pomacea, novel acquisition of an egg neurotoxin and a protein for making the calcareous eggshell may have been key adaptations enabling their transition from underwater to terrestrial egg deposition.Fil: Sun, Jin. Hong Kong University of Science and Technology; Hong KongFil: Mu, Huawei. Hong Kong Baptist University; Hong KongFil: Ip, Jack Chi Ho. Hong Kong Baptist University; Hong KongFil: Li, Runsheng. Hong Kong Baptist University; Hong KongFil: Xu, Ting. Hong Kong Baptist University; Hong KongFil: Accorsi, Alice. Howard Hughes Medical Institute; Estados Unidos. Stowers Institute for Medical Research; Estados UnidosFil: Alvarado, Alejandro Sanchez. Howard Hughes Medical Institute; Estados Unidos. Stowers Institute for Medical Research; Estados UnidosFil: Ross, Eric. Howard Hughes Medical Institute; Estados Unidos. Stowers Institute for Medical Research; Estados UnidosFil: Lan, Yi. Hong Kong University of Science and Technology; Hong KongFil: Sun, Yanan. Hong Kong University of Science and Technology; Hong KongFil: Castro Vazquez, Alfredo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Fisiología; ArgentinaFil: Vega, Israel Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Fisiología; ArgentinaFil: Heras, Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Ituarte, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Van Bocxlaer, Bert. Centre National de la Recherche Scientifique; FranciaFil: Hayes, Kenneth A.. Bernice Pauahi Bishop Museum; Estados UnidosFil: Cowie, Robert H.. University of Hawaii. Pacific Biosciences Research Center; Estados UnidosFil: Zhao, Zhongying. Hong Kong Baptist University; Hong KongFil: Zhang, Yu. Shenzhen University. College of Life Sciences and Oceanography. Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science; ArgentinaFil: Qian, Pei-Yuan. Hong Kong University of Science and Technology; Hong KongFil: Qiu, Jian-Wen. Hong Kong Baptist University; Hong Kon