A Genetic Test for Whether Pairs of Hermaphrodites Can Cross-Fertilize in a Selfing Killifish.

Kryptolebias marmoratus, a small killifish that lives in mangrove habitat from southern Florida to Brazil, is one of the planet's only known self-fertilizing hermaphroditic vertebrates. Generation after generation, hermaphroditic individuals simultaneously produce sperm and eggs and internally self-fertilize to produce what are, in effect, highly inbred clones of themselves. Although populations are composed primarily of hermaphrodites, they also contain some true males. The frequency of males in a population varies geographically, from <2% in Florida to as high as 25% in Belize. Males are known to mate occasionally with hermaphrodites, thereby releasing genetic variation that has profound consequences for population genetic structure. However, it is unknown whether hermaphrodites can or do sporadically mate with each other also. Here, we test whether hermaphroditic individuals of the killifish Kryptolebias marmoratus are capable of crossing with one another, in addition to their much more common habits of self-fertilization and occasional outcrossing with pure males. We employ an experimental design in which replicate hermaphrodite pairs were housed together and allowed to reproduce naturally. Among 173 embryos screened at diagnostic microsatellite loci, all were found to result from selfing (i.e., no embryos were the product of a hermaphrodite cross). We thus conclude that hermaphrodite pairs are unlikely to cross, or do so exceedingly rarely

Anti-inflammatory Effects of Abdominal Vagus Nerve Stimulation on Experimental Intestinal Inflammation

Electrical stimulation of the cervical vagus nerve is an emerging treatment for inflammatory bowel disease (IBD). However, side effects from cervical vagal nerve stimulation (VNS) are often reported by patients. Here we hypothesized that stimulating the vagus nerve closer to the end organ will have fewer off-target effects and will effectively reduce intestinal inflammation. Specifically, we aimed to: (i) compare off-target effects during abdominal and cervical VNS; (ii) verify that VNS levels were suprathreshold; and (iii) determine whether abdominal VNS reduces chemically-induced intestinal inflammation in rats. An electrode array was developed in-house to stimulate and record vagal neural responses. In a non-recovery experiment, stimulation-induced off-target effects were measured by implanting the cervical and abdominal vagus nerves of anaesthetized rats (n = 5) and recording changes to heart rate, respiration and blood pressure during stimulation (10 Hz; symmetric biphasic current pulse; 320 nC per phase). In a chronic experiment, the efficacy of VNS treatment was assessed by implanting an electrode array onto the abdominal vagus nerve and recording in vivo electrically-evoked neural responses during the implantation period. After 14 days, the intestine was inflamed with TNBS (2.5% 2,4,6-trinitrobenzene sulphonic acid) and rats received therapeutic VNS (n = 7; 10 Hz; 320 nC per phase; 3 h/day) or no stimulation (n = 8) for 4.5 days. Stool quality, plasma C-reactive protein and histology of the inflamed intestine were assessed. Data show that abdominal VNS had no effect (two-way RM-ANOVA: P ≥ 0.05) on cardiac, respiratory and blood pressure parameters. However, during cervical VNS heart rate decreased by 31 ± 9 beats/minute (P ≥ 0.05), respiration was inhibited and blood pressure decreased. Data addressing efficacy of VNS treatment show that electrically-evoked neural response thresholds remained stable (one-way RM ANOVA: P ≥ 0.05) and therapeutic stimulation remained above threshold. Chronically stimulated rats, compared to unstimulated rats, had improved stool quality (two-way RM ANOVA: P < 0.0001), no blood in feces (P < 0.0001), reduced plasma C-reactive protein (two-way RM ANOVA: P < 0.05) and a reduction in resident inflammatory cell populations within the intestine (Kruskal–Wallis: P < 0.05). In conclusion, abdominal VNS did not evoke off-target effects, is an effective treatment of TNBS-induced inflammation, and may be an effective treatment of IBD in humans

The extracellular surface of the GLP-1 receptor is a molecular trigger for biased agonism

Ligand-directed signal bias offers opportunities for sculpting molecular events, with the promise of better, safer therapeutics. Critical to the exploitation of signal bias is an understanding of the molecular events coupling ligand binding to intracellular signaling. Activation of class B G protein-coupled receptors is driven by interaction of the peptide N terminus with the receptor core. To understand how this drives signaling, we have used advanced analytical methods that enable separation of effects on pathway-specific signaling from those that modify agonist affinity and mapped the functional consequence of receptor modification onto three-dimensional models of a receptor-ligand complex. This yields molecular insights into the initiation of receptor activation and the mechanistic basis for biased agonism. Our data reveal that peptide agonists can engage different elements of the receptor extracellular face to achieve effector coupling and biased signaling providing a foundation for rational design of biased agonists

Indicators of ‘critical’ outcomes in 941 horses seen ‘out-of-hours’ for colic

Background: This study aimed to describe the presentation and outcomes of horses with signs of colic (abdominal pain) seen ‘out-of-hours’ in equine practice. Methods: This was a retrospective study of horses seen ‘out-of-hours’ with colic by two equine veterinary practices between 2011-2013. Case outcomes were categorised as ‘critical’ or ‘not critical’. A critical outcome was defined as requiring medical or surgical hospital treatment, or resulting in euthanasia or death. A non-critical outcome was defined as resolving with simple medical treatment. A hierarchical generalised linear model was used to identify ‘red flag’ parameters (aspects of signalment, history and presenting clinical signs) associated with critical outcomes.Results: Data were retrieved from 941 cases that presented with colic; 23.9% (n=225/941) were critical. Variables significantly associated with the likelihood of a critical outcome in the final multivariable mode were: increased heart rate (p [less than] 0.001), age of the horse (p=0.013) and abnormal mucous membrane colour (p [less than] 0.001). Overall 18% of cases (n=168/941) were euthanased.Conclusions: This study highlights the mortality associated with colic. The ‘red flag’ parameters identified should be considered an essential component of the primary assessment of horses with colic

Retrospective case series to identify the most common conditions seen ‘out-of-hours’ by first-opinion equine veterinary practitioners

Background: The study aim was to describe conditions seen ‘out-of-hours’ in equine practice. Methods: This was a retrospective case series of first opinion ‘out-of-hours’ cases seen at two equine practices between 2011-2013. Data was retrieved on case presentation, diagnostic testing, treatment administered and outcome, and diseases categorised using a systems-based coding system. A hierarchical logistic regression, formulated using a Generalised Linear Model, was used to identify clinical variables associated with a binary outcome of ‘critical’ cases (required hospitalisation or euthanasia or died).Results: Data from 2,602 cases were analysed. The most common reasons for ‘out-of-hours’ visits were colic (35%, n=923/2,620), wounds (20%, n=511/2,620) and lameness (11%, n=288/2,620). The majority of cases required a single treatment (58%, n=1,475/2,550), 26% (n=656/2,550) needed multiple treatments, and 13% (n=339/2,550) were euthanased. Eighteen percent (n=480/2602) of cases had a critical outcome. Increased heart rate at primary presentation was associated with critical outcome in both practices (Practice A, OR 1.07 (95%CI 1.06-1.09), Practice B OR 1.08 (95%CI 1.07-1.09; p [less than] 0.001)).Conclusion: Colic, wounds and lameness were the most common equine ‘out-of-hours’ conditions; 13% of cases were euthanased. Further research is required into out-of-hours euthanasia decision-making

Archiving primary data: solutions for long-term studies

The recent trend for journals to require open access to primary data included in publications has been embraced by many biologists, but has caused apprehension amongst researchers engaged in long-term ecological and evolutionary studies. A worldwide survey of 73 principal investigators (Pls) with long-term studies revealed positive attitudes towards sharing data with the agreement or involvement of the PI, and 93% of PIs have historically shared data. Only 8% were in favor of uncontrolled, open access to primary data while 63% expressed serious concern. We present here their viewpoint on an issue that can have non-trivial scientific consequences. We discuss potential costs of public data archiving and provide possible solutions to meet the needs of journals and researchers

Gut microbiota and sirtuins in obesity-related inflammation and bowel dysfunction

Obesity is a chronic disease characterized by persistent low-grade inflammation with alterations in gut motility. Motor abnormalities suggest that obesity has effects on the enteric nervous system (ENS), which controls virtually all gut functions. Recent studies have revealed that the gut microbiota can affect obesity and increase inflammatory tone by modulating mucosal barrier function. Furthermore, the observation that inflammatory conditions influence the excitability of enteric neurons may add to the gut dysfunction in obesity. In this article, we discuss recent advances in understanding the role of gut microbiota and inflammation in the pathogenesis of obesity and obesity-related gastrointestinal dysfunction. The potential contribution of sirtuins in protecting or regulating the circuitry of the ENS under inflamed states is also considered

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic