Barcoding Nemo: DNA-Based Identifications for the Ornamental Fish Trade

BACKGROUND:Trade in ornamental fishes represents, by far, the largest route for the importation of exotic vertebrates. There is growing pressure to regulate this trade with the goal of ensuring that species are sustainably harvested and that their point of origin is accurately reported. One important element of such regulation involves easy access to specimen identifications, a task that is currently difficult for all but specialists because of the large number of species involved. The present study represents an important first step in making identifications more accessible by assembling a DNA barcode reference sequence library for nearly half of the ornamental fish species imported into North America. METHODOLOGY/PRINCIPAL FINDINGS:Analysis of the cytochrome c oxidase subunit I (COI) gene from 391 species from 8 coral reef locations revealed that 98% of these species exhibit distinct barcode clusters, allowing their unambiguous identification. Most species showed little intra-specific variation (adjusted mean = 0.21%), but nine species included two or three lineages showing much more divergence (2.19-6.52%) and likely represent overlooked species complexes. By contrast, three genera contained a species pair or triad that lacked barcode divergence, cases that may reflect hybridization, young taxa or taxonomic over-splitting. CONCLUSIONS/SIGNIFICANCE:Although incomplete, this barcode library already provides a new species identification tool for the ornamental fish industry, opening a realm of applications linked to collection practices, regulatory control and conservation

Subintimal Double-Barrel Restenting of an Occluded Primary Stented Superficial Femoral Artery

In-stent re-stenosis is a frequent complication of endovascular stents, especially in the superficial femoral artery (SFA). Endovascular re-intervention of in- or peri-stent occlusive disease consists of recanilization through the occluded stent. In our case report, we describe the endovascular treatment of a previously placed stent in the SFA. We unintentionally passed the affected stent subintimally, in a double barrel fashion next to the first stent. The procedure was without any complications and with a successfull angiographic result. At one year follow-up the patient still has no complaints and the stent is still patent

Zfy genes are required for efficient meiotic sex chromosome inactivation (MSCI) in spermatocytes

During spermatogenesis, germ cells that fail to synapse their chromosomes or fail to undergo meiotic sex chromosome inactivation (MSCI) are eliminated via apoptosis during mid-pachytene. Previous work showed that Y-linked genes Zfy1 and Zfy2 act as "executioners" for this checkpoint, and that wrongful expression of either gene during pachytene triggers germ cell death. Here, we show that in mice, Zfy genes are also necessary for efficient MSCI and the sex chromosomes are not correctly silenced in Zfy-deficient spermatocytes. This unexpectedly reveals a triple role for Zfy at the mid-pachytene checkpoint in which Zfy genes first promote MSCI, then monitor its progress (since if MSCI is achieved, Zfy genes will be silenced), and finally execute cells with MSCI failure. This potentially constitutes a negative feedback loop governing this critical checkpoint mechanism

DNA Analysis of Traded Shark Fins and Mobulid Gill Plates Reveals a High Proportion of Species of Conservation Concern

Continuously increasing demand for plant and animal products causes unsustainable depletion of biological resources. It is estimated that one-quarter of sharks and rays are threatened worldwide and although the global fin trade is widely recognized as a major driver, demand for meat, liver oil, and gill plates also represents a significant threat. This study used DNA barcoding and 16 S rRNA sequencing as a method to identify shark and ray species from dried fins and gill plates, obtained in Canada, China, and Sri Lanka. 129 fins and gill plates were analysed and searches on BOLD produced matches to 20 species of sharks and five species of rays or – in two cases – to a species pair. Twelve of the species found are listed or have been approved for listing in 2017 in the appendices of the Convention on International Trade in Endangered Species of Fauna and Flora (CITES), including the whale shark (Rhincodon typus), which was surprisingly found among both shark fin and gill plate samples. More than half of identified species fall under the IUCN Red List categories ‘Endangered’ and ‘Vulnerable’, raising further concerns about the impacts of this trade on the sustainability of these low productivity species

Emotional arousal in agenesis of the corpus callosum

While the processing of verbal and psychophysiological indices of emotional arousal have been investigated extensively in relation to the left and right cerebral hemispheres, it remains poorly understood how both hemispheres normally function together to generate emotional responses to stimuli. Drawing on a unique sample of nine high-functioning subjects with complete agenesis of the corpus callosum (AgCC), we investigated this issue using standardized emotional visual stimuli. Compared to healthy controls, subjects with AgCC showed a larger variance in their cognitive ratings of valence and arousal, and an insensitivity to the emotion category of the stimuli, especially for negatively-valenced stimuli, and especially for their arousal. Despite their impaired cognitive ratings of arousal, some subjects with AgCC showed large skin-conductance responses, and in general skin-conductance responses discriminated emotion categories and correlated with stimulus arousal ratings. We suggest that largely intact right hemisphere mechanisms can support psychophysiological emotional responses, but that the lack of interhemispheric communication between the hemispheres, perhaps together with dysfunction of the anterior cingulate cortex, interferes with normal verbal ratings of arousal, a mechanism in line with some models of alexithymia

Serial intravascular ultrasound assessment of changes in coronary atherosclerotic plaque dimensions and composition: an update

This manuscript reviews the use of serial intravascular ultrasound (IVUS) examination of coronary atherosclerosis in recent observational studies and randomized trials that revealed the effects of cholesterol-lowering and lipid-modifying therapies and offered novel insight into plaque progression and regression. We discuss the value of plaque progression–regression as complementary imaging endpoint and potential surrogate marker of cardiovascular event risk. In addition, the progress in serial assessment of coronary plaque composition and plaque vulnerability by radiofrequency-based analyses is reviewed. Finally, we report on the evaluation of true vessel remodelling in recent serial IVUS trials and discuss the future perspective of serial invasive imaging of coronary atherosclerosis

Extensive meiotic asynapsis in mice antagonises meiotic silencing of unsynapsed chromatin and consequently disrupts meiotic sex chromosome inactivation

Chromosome synapsis during zygotene is a prerequisite for the timely homologous recombinational repair of meiotic DNA double-strand breaks (DSBs). Unrepaired DSBs are thought to trigger apoptosis during midpachytene of male meiosis if synapsis fails. An early pachytene response to asynapsis is meiotic silencing of unsynapsed chromatin (MSUC), which, in normal males, silences the X and Y chromosomes (meiotic sex chromosome inactivation [MSCI]). In this study, we show that MSUC occurs in Spo11-null mouse spermatocytes with extensive asynapsis but lacking meiotic DSBs. In contrast, three mutants (Dnmt3l, Msh5, and Dmc1) with high levels of asynapsis and numerous persistent unrepaired DSBs have a severely impaired MSUC response. We suggest that MSUC-related proteins, including the MSUC initiator BRCA1, are sequestered at unrepaired DSBs. All four mutants fail to silence the X and Y chromosomes (MSCI failure), which is sufficient to explain the midpachytene apoptosis. Apoptosis does not occur in mice with a single additional asynapsed chromosome with unrepaired meiotic DSBs and no disturbance of MSCI

Correlation of an epigenetic mitotic clock with cancer risk.

BACKGROUND: Variation in cancer risk among somatic tissues has been attributed to variations in the underlying rate of stem cell division. For a given tissue type, variable cancer risk between individuals is thought to be influenced by extrinsic factors which modulate this rate of stem cell division. To date, no molecular mitotic clock has been developed to approximate the number of stem cell divisions in a tissue of an individual and which is correlated with cancer risk. RESULTS: Here, we integrate mathematical modeling with prior biological knowledge to construct a DNA methylation-based age-correlative model which approximates a mitotic clock in both normal and cancer tissue. By focusing on promoter CpG sites that localize to Polycomb group target genes that are unmethylated in 11 different fetal tissue types, we show that increases in DNA methylation at these sites defines a tick rate which correlates with the estimated rate of stem cell division in normal tissues. Using matched DNA methylation and RNA-seq data, we further show that it correlates with an expression-based mitotic index in cancer tissue. We demonstrate that this mitotic-like clock is universally accelerated in cancer, including pre-cancerous lesions, and that it is also accelerated in normal epithelial cells exposed to a major carcinogen. CONCLUSIONS: Unlike other epigenetic and mutational clocks or the telomere clock, the epigenetic clock proposed here provides a concrete example of a mitotic-like clock which is universally accelerated in cancer and precancerous lesions

Avian influenza at both ends of a migratory flyway: characterizing viral genomic diversity to optimize surveillance plans for North America

Although continental populations of avian influenza viruses are genetically distinct, transcontinental reassortment in low pathogenic avian influenza (LPAI) viruses has been detected in migratory birds. Thus, genomic analyses of LPAI viruses could serve as an approach to prioritize species and regions targeted by North American surveillance activities for foreign origin highly pathogenic avian influenza (HPAI). To assess the applicability of this approach, we conducted a phylogenetic and population genetic analysis of 68 viral genomes isolated from the northern pintail (Anas acuta) at opposite ends of the Pacific migratory flyway in North America. We found limited evidence for Asian LPAI lineages on wintering areas used by northern pintails in California in contrast to a higher frequency on breeding locales of Alaska. Our results indicate that the number of Asian LPAI lineages observed in Alaskan northern pintails, and the nucleotide composition of LPAI lineages, is not maintained through fall migration. Accordingly, our data indicate that surveillance of Pacific Flyway northern pintails to detect foreign avian influenza viruses would be most effective in Alaska. North American surveillance plans could be optimized through an analysis of LPAI genomics from species that demonstrate evolutionary linkages with European or Asian lineages and in regions that have overlapping migratory flyways with areas of HPAI outbreaks