Investigaciones recientes sobre el langostino nativo Macrobrachium americanum (Decapoda: Palaemonidae) con fines de acuicultura y conservación

where good management practices on aquaculture are mandatory. The economic and ecological importance of prawns of the Genus Macrobrachium cause an impact at a global level involving economic, academic and social aspects. Macrobrachium americanum appears as one of the genus species with high nutritional value and an economic demand in the national and international markets, as well as a vital income for fisherman and producers of this species. For researchers, it is a challenge to find solutions to culture and propose conservation measures for M. americanum with emphasis on development, nutrition and reproduction. Although there are scientific studies supporting the economic importance of this species, our knowledge about its cultivation, reproduction and conservation is limited. This paper summarizes the latest studies made in cooperation with M. americanum in research lead by the Centro de Investigaciones Biológicas del Noroeste, Mexico. After several years of continuous research, it is considered that those efforts have produced useful information for the sustainable exploitation, conservation and basic management practices of this species.En los últimos tiempos ha existido una gran preocupación por la conservación y uso adecuados de los recursos naturales vivos, donde las buenas prácticas de manejo en la acuicultura son importantes. La importancia económica y pesquera de los langostinos del Género Macrobrachium causa un impacto a nivel global que incluye aspectos económicos, académicos y sociales. Macrobrachium americanum se presenta como una de las especies del género con alto valor nutritivo y demanda económica en el mercado nacional e internacional y constituye un importante ingreso para los pescadores y productores de esta especie. Para los investigadores es un desafío encontrar soluciones para la conservación del M. americanum con énfasis en el desarrollo, la nutrición y la reproducción. Aunque existen estudios científicos que avalan la importancia económica de esta especie, nuestro conocimiento sobre su cultivo, reproducción y conservación es limitado. Este artículo resume algunos estudios en colaboración sobre M. americanum, liderados por el Centro de Investigaciones Biológicas del Noroeste, México. Después de varios años de investigación continua, se considera que esos esfuerzos han producido información útil para la explotación sostenible, conservación y las posibles medidas de manejo para esta especie

Particulate matter Air Pollution induces hypermethylation of the p16 promoter Via a mitochondrial ROS-JNK-DNMT1 pathway

Exposure of human populations to chronically elevated levels of ambient particulate matter air pollution < 2.5 μm in diameter (PM2.5) has been associated with an increase in lung cancer incidence. Over 70% of lung cancer cell lines exhibit promoter methylation of the tumor suppressor p16, an epigenetic modification that reduces its expression. We exposed mice to concentrated ambient PM2.5 via inhalation, 8 hours daily for 3 weeks and exposed primary murine alveolar epithelial cells to daily doses of fine urban PM (5 µg/cm2). In both mice and alveolar epithelial cells, PM exposure increased ROS production, expression of the DNA methyltransferase 1 (DNMT1), and methylation of the p16 promoter. In alveolar epithelial cells, increased transcription of DNMT1 and methylation of the p16 promoter were inhibited by a mitochondrially targeted antioxidant and a JNK inhibitor. These findings provide a potential mechanism by which PM exposure increases the risk of lung cancer

From father to son: transgenerational effect of tetracycline on sperm viability

The broad-spectrum antibiotic tetracycline is used in animal production, antimicrobial therapy, and for curing arthropods infected with bacterial endosymbionts such as Wolbachia. Tetracycline inhibits mitochondrial translation, and recent evidence indicates that male reproductive traits may be particularly sensitive to this antibiotic. Here, we report the first multi-generation investigation of tetracycline's effects on ejaculate traits. In a study of the pseudoscorpion, Cordylochernes scorpioides, in which siblings were randomly assigned to control and tetracycline treatments across replicate full-sibling families, tetracycline did not affect body size in either sex, female reproduction or sperm number. However, tetracycline-treated males exhibited significantly reduced sperm viability compared to control males, and transmitted this toxic effect of tetracycline on sperm to their untreated sons but not to their F2 grandsons. These results are consistent with tetracycline-induced epigenetic changes in the male germline, and suggest the need for further investigation of transgenerational effects of tetracycline on male reproductive function

Particulate Matter-Induced Lung Inflammation Increases Systemic Levels of PAI-1 and Activates Coagulation Through Distinct Mechanisms

Exposure of human populations to ambient particulate matter (PM) air pollution significantly contributes to the mortality attributable to ischemic cardiovascular events. We reported that mice treated with intratracheally instilled PM develop a prothrombotic state that requires the release of IL-6 by alveolar macrophages. We sought to determine whether exposure of mice to PM increases the levels of PAI-1, a major regulator of thrombolysis, via a similar or distinct mechanism. mice but was absent in mice treated with etanercept, a TNF-α inhibitor. Treatment with etanercept did not prevent the PM-induced tendency toward thrombus formation.Mice exposed to inhaled PM exhibited a TNF-α-dependent increase in PAI-1 and an IL-6-dependent activation of coagulation. These results suggest that multiple mechanisms link PM-induced lung inflammation with the development of a prothrombotic state

Solutions to the optimal network design problem with shipments related to transportation cost

Two versions of an optimal network design problem with shipments proportional to transportation costs are formulated. Extensions of an algorithm developed in prior research for solving these problems are proposed and tested. The performance of the algorithms is found to improve substantially as the dependence of shipments on costs is increased. Moreover, the optimal solutions obtained are unexpectedly robust with respect to a wide range of transportation cost assumptions. These findings could have important computational and policy implications if applicable to larger networks.

Detection and mixing of two modulated optical signals using only a single GaAs FET (experimental study)

GaAs FET’s are widely used in system such LNA, PA, mixers, frequency multipliers, oscillators and attenuators. Recent works have shown the usefulness of these transistors in the optoelectronics field, as photodetectors or optoelectric mixers. In this paper an experimental study explores the idea of unifying the detection and mixing of two optical modulated signals at different wavelengths, using a single GaAs FET. The FET is biased at fixed VGS and VDS and loaded to 50,while two optical modulated signals of different wavelength and frequencies are illuminating the gate of the FET. The results show that the FET can detect both signals and by means of the inherent nonlinearity in the channel of the FET, the sum and difference of both frequencies appear (up and down conversion). Moreover, this type of architecture demonstrates low distortion in contrast to its counterpart (electric and optoelectric mixers) and also, to obtain the same power level for the up and down conversion frequencies, the power level required for the RF and LO signals are much lower than the case of electric and optoelectric mixers. To our knowledge this is the first time that a single FET is used for detecting and mixing two optical modulated signals at the same time

Mitochondrial Complex III-generated Oxidants Activate ASK1 and JNK to Induce Alveolar Epithelial Cell Death following Exposure to Particulate Matter Air Pollution*

We have previously reported that airborne particulate matter air pollution (PM) activates the intrinsic apoptotic pathway in alveolar epithelial cells through a pathway that requires the mitochondrial generation of reactive oxygen species (ROS) and the activation of p53. We sought to examine the source of mitochondrial oxidant production and the molecular links between ROS generation and the activation of p53 in response to PM exposure. Using a mitochondrially targeted ratiometric sensor (Ro-GFP) in cells lacking mitochondrial DNA (ρ0 cells) and cells stably expressing a small hairpin RNA directed against the Rieske iron-sulfur protein, we show that site III of the mitochondrial electron transport chain is primarily responsible for fine PM (PM2.5)-induced oxidant production. In alveolar epithelial cells, the overexpression of SOD1 prevented the PM2.5-induced ROS generation from the mitochondria and prevented cell death. Infection of mice with an adenovirus encoding SOD1 prevented the PM2.5-induced death of alveolar epithelial cells and the associated increase in alveolar-capillary permeability. Treatment with PM2.5 resulted in the ROS-mediated activation of the oxidant-sensitive kinase ASK1 and its downstream kinase JNK. Murine embryonic fibroblasts from ASK1 knock-out mice, alveolar epithelial cells transfected with dominant negative constructs against ASK1, and pharmacologic inhibition of JNK with SP600125 (25 μm) prevented the PM2.5-induced phosphorylation of p53 and cell death. We conclude that particulate matter air pollution induces the generation of ROS primarily from site III of the mitochondrial electron transport chain and that these ROS activate the intrinsic apoptotic pathway through ASK1, JNK, and p53

Membrane Potential Greatly Enhances Superoxide Generation by the Cytochrome bc1 Complex Reconstituted into Phospholipid Vesicles*

The mitochondrial cytochrome bc1 complex (ubiquinol/cytochrome c oxidoreductase) is generally thought to generate superoxide anion that participates in cell signaling and contributes to cellular damage in aging and degenerative disease. However, the isolated, detergent-solubilized bc1 complex does not generate measurable amounts of superoxide except when inhibited by antimycin. In addition, indirect measurements of superoxide production by cells and isolated mitochondria have not clearly resolved the contribution of the bc1 complex to the generation of superoxide by mitochondria in vivo, nor did they establish the effect, if any, of membrane potential on superoxide formation by this enzyme complex. In this study we show that the yeast cytochrome bc1 complex does generate significant amounts of superoxide when reconstituted into phospholipid vesicles. The rate of superoxide generation by the reconstituted bc1 complex increased exponentially with increased magnitude of the membrane potential, a finding that is compatible with the suggestion that membrane potential inhibits electron transfer from the cytochrome bL to bH hemes, thereby promoting the formation of a ubisemiquinone radical that interacts with oxygen to generate superoxide. When the membrane potential was further increased, by the addition of nigericin or by the imposition of a diffusion potential, the rate of generation of superoxide was further accelerated and approached the rate obtained with antimycin. These findings suggest that the bc1 complex may contribute significantly to superoxide generation by mitochondria in vivo, and that the rate of superoxide generation can be controlled by modulation of the mitochondrial membrane potential