An isochore-like structure in the genome of the flatworm schistosoma mansoni

Eukaryotic genomes are compositionally heterogeneous, that is, composed by regions that differ in guanine–cytosine (GC) content (isochores). The most well documented case is that of vertebrates (mainly mammals) although it has been also noted among unicellular eukaryotes and invertebrates. In the human genome, regarded as a typical mammal, this heterogeneity is associated with several features. Specifically, genes located in GC-richest regions are the GC3-richest, display CpG islands and have shorter introns. Furthermore, these genes are more heavily expressed and tend to be located at the extremes of the chromosomes. Although the compositional heterogeneity seems to be widespread among eukaryotes, the associated properties noted in the human genome and other mammals have not been investigated in depth in other taxa. Here we provide evidence that the genome of the parasitic flatworm Schistosoma mansoni is compositionally heterogeneous and exhibits an isochore-like structure, displaying some features associated, until now, only with the human and other vertebrate genomes, with the exception of gene concentration

Desarrollo de un método para evaluar el daño ocasionado por aves en cultivos comerciales de soja recién emergida = Development of a method for assessing damage caused by birds in sprouting soybean in commercial crops

El cultivo de soja (Glycine max) es uno de los principales rubros productivos en Sudamérica. Algunas especies de aves pueden consumir los cotiledones de las plántulas de soja recién emergidas causando daño al cultivo. Con el objetivo de contar con estimaciones precisas del daño por aves en soja recién emergida se desarrolló un método de evaluación, suponiendo un gradiente de daño en función de la distancia del lote a parches con árboles usados como refugio por las aves. En base a estimaciones de media, desvío estándar, intervalo de confianza y varianza de los datos obtenidos en seis lotes del oeste de Uruguay se determinó un diseño y tamaño de muestra óptimo para minimizar el esfuerzo y tiempo de evaluación, manteniendo un alto nivel de precisión. Dicha metodología fue posteriormente aplicada en ocho lotes, obteniéndose un daño de 10 a 50% cerca de los árboles y de 1 a 5% en el resto del cultivo. El método propuesto brinda información objetiva del daño y constituye una herramienta útil para la toma de decisiones a nivel predial.Soybean (Glycine max) cultivation is one of the main commodities in South America. Some bird species can consume the cotyledons of soybean seedlings newly emerged, causing crop damage. In order to have accurate estimates of the bird damage in sprouting soybean, we developed an assessment method assuming a gradient of damage based on the distance from the crop to a patch of trees used as shelter by birds. Based on the mean, standard deviation, confidence interval and data variance, obtained in six soybean fields located in western Uruguay, we determined a sampling design and optimal sample size to minimize the effort and time evaluation, maintaining a high level of accuracy. We subsequently applied this methodology on eight soybean fields. The damage near trees was between 10 and 50% while in the rest of the field was between 1 and 5%. The proposed method provides objective information on losses occurred, constituting a useful tool for decision making at farm level.EEA ParanáFil: Bou, Nadia. Instituto de Investigaciones Biológicas Clemente Estable (IIBCE). Departamento de Biodiversidad y Genética; UruguayFil: Dardanelli, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Olivera, Lourdes. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental La Estanzuela; UruguayFil: Tellechea, Guillermo. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental La Estanzuela; UruguayFil: Addy Orduna, Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Canavelli, Sonia Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Rodríguez, Ethel. Ministerio de Ganadería, Agricultura y Pesca (MGAP). Dirección General de Servicios Agrícolas; Urugua

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Nicarbazin as an oral contraceptive in eared doves

Eared doves (Zenaida auriculata) are responsible for substantial losses in cereal and oil crops as well as in dairy and feedlot production in the southern cone of South America. Various strategies have been shown to be effective in reducing damage at the farm scale, but in some scenarios, it is necessary to also incorporate population control methods due to excessive bird population size. An alternative approach to reduce pest bird populations is the use of contraceptive methods, minimizing the impact on the environment and non-target populations. Nicarbazin is registered in the United States as a contraceptive for Branta canadensis and Columba livia. The aim of this study was to measure the effect of nicarbazin on the reproductive performance of eared doves in captivity. This study included eleven caged pairs of nesting eared doves in three experimental phases (pre-treatment, treatment, recovery). Each pair was exposed to nicarbazin bait for 4 h per day. The contraceptive used was OvoControlP® (0.5% nicarbazin) ground with a millstone into particles of 0.5–3.0 mm. Daily bait consumption and reproductive variables per pair (egg laying and 14-day-old fledgling) were recorded, and levels of 4,4′dinitrocarbanilide were measured in feces and unhatched eggs. Median consumption was 4.2 g of bait/pair/day. We observed a 62% reduction in the number of viable eggs and successful nestlings in the treatment phasein contrast to pre-treatment (V = 36; p = 0.006). There were no significant differences (V = 0; p = 1) in the number of viable eggs between the pretreatment and recovery phases. Median daily bait consumption by pairs producing zero or one nestling (4.4 and 5.0 g/pair/day respectively) was significantly higher than that of pairs that had two nestlings (3.4 g/pair) during the treatment phase (t = 2.0; p = 0.002). Nicarbazin was effective in reducing reproductive performance of eared doves, and its effect was reversible when the treatment finished

Long term exposure to deltamethrin causes a dual effect on plasma membrane Ca²⁺-ATPase activity and reduces its mRNA levels in human lymphocytes

271-278Deltamethrin (Delt), a type II pyrethroid used worldwide, is chemically and biologically stable and displays mild toxicity in mammals, but chronic exposure causes toxic effects on the immune system. In order to clarify the damage of deltamethrin to lymphocytes, we studied the effect of deltamethrin on the catalytic activity and expression levels of the plasma membrane Ca2+-ATPase (PMCA) using human lymphocytes as a model. Lymphocytes were incubated with Delt at concentrations ranging from 2 to 133 µM for 36 h, followed by plasma membrane purification and analysis of PMCA activity. A significant increase of 122% in PMCA activity was observed with 2 µM Delt, while concentrations of 40 and 60 µM inhibited activity of PMCA to 58.3% below the control. The viability of lymphocytes was most affected at concentrations higher than 133 µM, the concentration that inhibited PMCA activity to 30.5%. Expression of PMCA was assessed by qPCR and the data showed a decrease in the amount of PMCA transcripts as a result of treatment with deltamethrin. Our results have shown that deltamethrin treatment of human lymphocytes in culture influences PMCA activity as measured in isolated plasma membranes as well as the PMCA mRNA levels sampled at different time points. It indicates disruption of the enzyme activity which would compromise cellular signaling and eventually may lead to cell death

Desarrollo de un método para evaluar el daño ocasionado por aves en cultivos comerciales de soja recién emergida

Soybean (Glycine max) cultivation is one of the main commodities in South America. Some bird species can consume the cotyledons of soybean seedlings newly emerged, causing crop damage. In order to have accurate estimates of the bird damage in sprouting soybean, we developed an assessment method assuming a gradient of damage based on the distance from the crop to a patch of trees used as shelter by birds. Based on the mean, standard deviation, confidence interval and data variance, obtained in six soybean fields located in western Uruguay, we determined a sampling design and optimal sample size to minimize the effort and time evaluation, maintaining a high level of accuracy. We subsequently applied this methodology on eight soybean fields. The damage near trees was between 10 and 50% while in the rest of the field was between 1 and 5%. The proposed method provides objective information on losses occurred, constituting a useful tool for decision making at farm level.El cultivo de soja (Glycine max) es uno de los principales rubros productivos en Sudamérica. Algunas especies de aves pueden consumir los cotiledones de las plántulas de soja recién emergidas causando daño al cultivo. Con el objetivo de contar con estimaciones precisas del daño por aves en soja recién emergida se desarrolló un método de evaluación, suponiendo un gradiente de daño en función de la distancia del lote a parches con árboles usados como refugio por las aves. En base a estimaciones de media, desvío estándar, intervalo de confianza y varianza de los datos obtenidos en seis lotes del oeste de Uruguay se determinó un diseño y tamaño de muestra óptimo para minimizar el esfuerzo y tiempo de evaluación, manteniendo un alto nivel de precisión. Dicha metodología fue posteriormente aplicada en ocho lotes, obteniéndose un daño de 10 a 50% cerca de los árboles y de 1 a 5% en el resto del cultivo. El método propuesto brinda información objetiva del daño y constituye una herramienta útil para la toma de decisiones a nivel predial

Acanthocytosis and brain damage in area postrema and choroid plexus: Description of novel signs of Loxosceles apachea envenomation in rats.

Loxocelism is a neglected medical problem that depends on its severity, can cause a cutaneous or viscero-cutaneous syndrome. This syndrome is characterized by hemostatic effects and necrosis, and the severity of the loxoscelism depends on the amount of venom injected, the zone of inoculation, and the species. In the Chihuahuan desert, the most abundant species is L. apachea. Its venom and biological effects are understudied, including neurological effects. Thus, our aim is to explore the effect of this regional species of medical interest in the United States-Mexico border community, using rat blood and central nervous system (CNS), particularly, two brain structures involved in brain homeostasis, Area postrema (AP) and Choroid plexus (PC). L. apachea specimens were collected and venom was obtained. Different venom concentrations (0, 0.178 and 0.87 μg/g) were inoculated into Sprague-Dawley rats (intraperitoneal injection). Subsequently, blood was extracted and stained with Wright staining; coronal sections of AP were obtained and stained with Hematoxylin-Eosin (HE) staining and laminin γ immunolabelling, the same was done with CP sections. Blood, AP and CP were observed under the microscope and abnormalities in erythrocytes and fluctuation in leukocyte types were described and quantified in blood. Capillaries were also quantified in AP and damage was described in CP. L. apachea venom produced a segmented neutrophil increment (neutrophilia), lymphocyte diminishment (leukopenia) and erythrocytes presented membrane abnormalities (acanthocytosis). Extravasated erythrocytes were observed in HE stained sections from both, AP and CP, which suggest that near to this section a hemorrhage is present; through immunohistofluorescence, a diminishment of laminin γ was observed in AP endothelial cells and in CP ependymal cells when these structures were exposed to L. apachea venom. In conclusion, L. apachea venom produced leukopenia, netrophilia and acanthocytosis in rat peripheral blood, and also generated hemorrhages on AP and CP through degradation of laminin γ

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Abstract Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0–640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom (40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation

Jefa del Departamento de Matemáticas Consejo Editorial del Departamento de Matemáticas Dr. Oscar Vega Amaya Coordinador General

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