Effects of salinity on survival, growth, reproductive and life span characteristics of <i>Artemia</i> populations from Urmia Lake and neighboring lagoons

This study deals with effects of different salinities on the survival, growth, reproductive and lifespan characteristics of three Artemia populations from Urmia Lake and small lagoons at the vicinity of the lake under laboratory conditions. Experimental salinities ranged from 75 to 175 g L-1. Salinity was proved to have significant impact on the majority of the characters studied in this survey. Growth and survival in bisexual A. urmiana and parthenogenetic Artemia from Lake Urmia were significantly higher with respect to the parthenogenetic Artemia from lagoons at most of the salinities tested. Reproductive characteristics such as total number of broods, total offspring number of offspring in each brood and number of offspring at each day of reproductive period reduced with increasing salinity. Moreover higher salinity prolonged the pre-reproductive period but shortened the total reproductive period. Higher salinities also affected the percentage of encystment and post-reproductive period, showing significantly higher values in parthenogenetic populations in comparison to bisexual A. urmiana

Rice H2A.Z negatively regulates genes responsive to nutrient starvation but promotes expression of key housekeeping genes

© The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. The H2A.Z histone variant plays a role in the modulation of environmental responses, but the nature of the associated mechanisms remains enigmatic. We investigated global H2A.Z deposition and transcriptomic changes in rice (Oryza sativa) upon exposure to phosphate (Pi) deficiency and in response to RNAi knockdown of OsARP6, which encodes a key component of the H2A.Z exchange complex. Both Pi deficiency and OsARP6-knockdown resulted in similar, profound effects on global H2A.Z distribution. H2A.Z in the gene body of stress-responsive genes was negatively correlated with gene expression, and this was more apparent in response to Pi deficiency. In contrast, the role of H2A.Z at the transcription start site (TSS) was more context dependent, acting as a repressor of some stress-responsive genes, but an activator of some genes with housekeeping functions. This was especially evident upon OsARP6-knockdown, which resulted in down-regulation of a number of genes linked to chloroplast function that contained decreases in H2A.Z at the TSS. Consistently, OsARP6-RNAi plants exhibited lower chlorophyll content relative to the wild-type. Our results demonstrate that gene body-localized H2A.Z plays a prominent role in repressing stress-responsive genes under non-inductive conditions, whereas H2A.Z at the TSS functions as a positive or negative regulator of transcription

A Chemogenetic Approach for the Optical Monitoring of Voltage in Neurons

Optical monitoring of neuronal voltage using fluorescent indicators is a powerful approach for the interrogation of the cellular and molecular logic of the nervous system. Herein, a semisynthetic tethered voltage indicator (STeVI1) based upon nile red is described that displays voltage sensitivity when genetically targeted to neuronal membranes. This environmentally sensitive probe allows for wash-free imaging and faithfully detects supra- and sub-threshold activity in neurons

Operation of a high-Tc_{c} SQUID gradiometer with a two-stage Joule-Thomson micro-cooler

Practical applications of high-T$_{c}$ SQUIDs require cheap, simple in operation, and cryogen-free cooling. Mechanical cryo-coolers are generally not suitable for operation with SQUIDs due to their inherent magnetic and vibrational noise. In this work, we utilized a Joule-Thomson microfluidic cooling system to operate our high-T$_{c}$ SQUIDs [1]. The micro-cooler system is based on a commercial desktop CryoLab unit from DEMCON kryoz [2]. It contains a two-stage MEMS micro-cooler with a base temperature of 75 K, gross cooling power of 75 mW@80 K, and temperature stability ± 50 mK. Our high-TC dc SQUID gradiometers were fabricated from YBa$_{2}$Cu$_{3}$O$_{7-x}$ thin films grown by pulsed laser deposition on 10 mm × 10 mm SrTiO$_{3}$ bicrystal substrates with 24° misorientation angle. The SQUID chip was glued onto a 0.3 mm thick silicon wafer chip carrier that was attached to the second stage of the cold head. The vacuum housing of the cold stage was made from non-magnetic material (polyethylene terephthalate, PET) and evacuated to a base pressure below 2x10$^{-3}$ mbar. The vacuum chamber features a 0.3 mm thick sapphire window that is placed above the sensor/cold stage. We demonstrated that the equivalent magnetic flux noise of the high-T$_{c}$ SQUID gradiometer is largely unaffected by the micro-cooler setup. The cut-off frequency of the 1/f noise in our SQUID measured on the micro-cooler was around 10 Hz. This indicates that the micro-cooler does not introduce significant magnetic fields in the vicinity of the cold stage. We thus demonstrate that such a microfluidic cooling system is a promising technology for cooling of high-T$_{c}$ SQUIDs in practical applications. We also used the micro-cooler system to build a prototype a magnetic ac susceptibility (ACS) system for detection of specific binding reactions between DNA target molecules and functionalized magnetic nanoparticles (fMNP) in liquid solution. The detection principle relies on changes in Brownian rotation dynamics of fMNPs. We present the results of experiments with various concentrations of magnetic nanoparticles and discuss further development of the portable magnetic bioassay system for detection of influenza virus using oligonucleotide-tagged magnetic nanoparticles with sub-picomolar sensitivity. [1] A. Kalabukhov et al., Supercond. Sci. Technol. 29 095014 (2016). [2] http://kryoz.nl/portfolio-item/cryolab-msg

Randomised primary health center based interventions to improve the diagnosis and treatment of undifferentiated fever and dengue in Vietnam

<p>Abstract</p> <p>Background</p> <p>Fever is a common reason for attending primary health facilities in Vietnam. Response of health care providers to patients with fever commonly consists of making a presumptive diagnosis and proposing corresponding treatment. In Vietnam, where malaria was brought under control, viral infections, notably dengue, are the main causes of undifferentiated fever but they are often misdiagnosed and inappropriately treated with antibiotics.</p> <p>This study investigate if educating primary health center (PHC) staff or introducing rapid diagnostic tests (RDTs) improve diagnostic resolution and accuracy for acute undifferentiated fever (AUF) and reduce prescription of antibiotics and costs for patients.</p> <p>Methods</p> <p>In a PHC randomized intervention study in southern Vietnam, the presumptive diagnoses for AUF patients were recorded and confirmed by serology on paired (acute and convalescence) sera. After one year, PHCs were randomized to four intervention arms: training on infectious diseases (A), the provision of RDTs (B), the combination (AB) and control (C). The intervention lasted from 2002 until 2006.</p> <p>Results</p> <p>The frequency of the non-etiologic diagnosis "undifferentiated fever" decreased in group AB, and - with some delay- also in group B. The diagnosis "dengue" increased in group AB, but only temporarily, although dengue was the most common cause of fever. A correct diagnosis for dengue initially increased in groups AB and B but only for AB this was sustained. Antibiotics prescriptions increased in group C. During intervention it initially declined in AB with a tendency to increase afterwards; in B it gradually declined. There was a substantial increase of patients' costs in B.</p> <p>Conclusions</p> <p>The introduction of RDTs for infectious diseases such as dengue, through free market principles, does improve the quality of the diagnosis and decreases the prescription of antibiotics at the PHC level. However, the effect is more sustainable in combination with training; without it RDTs lead to an excess of costs.</p

Non-Invasive Mapping of the Gastrointestinal Microbiota Identifies Children with Inflammatory Bowel Disease

Background: Pediatric inflammatory bowel disease (IBD) is challenging to diagnose because of the non-specificity of symptoms; an unequivocal diagnosis can only be made using colonoscopy, which clinicians are reluctant to recommend for children. Diagnosis of pediatric IBD is therefore frequently delayed, leading to inappropriate treatment plans and poor outcomes. We investigated the use of 16S rRNA sequencing of fecal samples and new analytical methods to assess differences in the microbiota of children with IBD and other gastrointestinal disorders. Methodology/Principal Findings: We applied synthetic learning in microbial ecology (SLiME) analysis to 16S sequencing data obtained from i) published surveys of microbiota diversity in IBD and ii) fecal samples from 91 children and young adults who were treated in the gastroenterology program of Children’s Hospital (Boston, USA). The developed method accurately distinguished control samples from those of patients with IBD; the area under the receiver-operating-characteristic curve (AUC) value was 0.83 (corresponding to 80.3% sensitivity and 69.7% specificity at a set threshold). The accuracy was maintained among data sets collected by different sampling and sequencing methods. The method identified taxa associated with disease states and distinguished patients with Crohn’s disease from those with ulcerative colitis with reasonable accuracy. The findings were validated using samples from an additional group of 68 patients; the validation test identified patients with IBD with an AUC value of 0.84 (e.g. 92% sensitivity, 58.5% specificity). Conclusions/Significance: Microbiome-based diagnostics can distinguish pediatric patients with IBD from patients with similar symptoms. Although this test can not replace endoscopy and histological examination as diagnostic tools, classification based on microbial diversity is an effective complementary technique for IBD detection in pediatric patients.Natural Sciences and Engineering Research Council of Canada (Award NSERC PGS D)National Institutes of Health (U.S.) (1-R21-A1084032-01A1