Environmental DNA as a tool to reconstruct catch composition for longline fisheries vessels

Global wild-capture fisheries are a large and diverse sector requiring various tools for fisheries-dependant data collection and effective Monitoring, Control and Surveillance (MCS). Here we present a novel protocol to collect eDNA from brine tanks onboard commercial longline vessels to reconstruct catch composition. We collected samples from nine vessels operating out of the Eastern Tuna Billfish Fishery, Australia, validating eDNA results with reliable catch data consisting of seven target and bycatch species. Environmental DNA was highly effective for detecting species retained on vessels without contamination or false positives. For four vessels, logbook data and eDNA were consistent with detections of all species. The remaining vessels detected all species except for rare catches of short-billed spearfish (Tetrapturus angustirostris). Similarities between rank abundance distributions of catch and eDNA reads were observed with logbook data mirrored when eDNA sequences were organised into rank order abundance. The method was effective at identifying highly abundant taxa retained in brine tanks- tuna (Thunnus spp.), swordfish (Xiphias gladius), marlin (Kajijia audax), and Atlantic Pomfret (Brama brama). Further research is required to validate how eDNA and other molecular monitoring tools can be scaled and applied to provide solutions for monitoring challenges in the fisheries sector.

'Nesting networks': Women's experiences of social network support in high-risk pregnancy

OBJECTIVE

Social support, an individual's social relationships (both online and offline), may provide protection against adverse mental health outcomes, such as anxiety and depression, which are high in women who have been hospitalised with high-risk pregnancy. This study explored the social support available to women at higher risk of preeclampsia during pregnancy by examining personal social networks.

DESIGN

Semi-structured interviews were accompanied by social network mapping using the web-based social networking tool GENIE.

SETTING

England.

PARTICIPANTS

Twenty-one women were recruited, of whom 18 were interviewed both during pregnancy and postnatally between April 2019 and April 2020. Nineteen women completed maps pre-natally, 17 women completed maps pre-natally and post-natally. Women were taking part in the BUMP study, a randomised clinical trial that included 2441 pregnant individuals at higher risk of preeclampsia and recruited at a mean of 20 weeks' gestation from 15 hospital maternity units in England between November 2018 and October 2019.

RESULTS

Women's social networks tightened during pregnancy. The inner network changed most dramatically postnatally with women reporting fewer network members. Interviews revealed networks were primarily 'real-life' rather than online social networks, with members providing emotional, informational, and practical support. Women with a high-risk pregnancy valued the relationships they developed with health professionals during pregnancy, and would like their midwife to have a more central role in their networks by providing informational and, where needed, emotional support. The social network mapping data supported the qualitative accounts of changing networks across high-risk pregnancy.

CONCLUSION

Women with a high-risk pregnancy seek to build "nesting networks" to support them through pregnancy into motherhood. Different types of support are sought from trusted sources. Midwives can play a key role.

PRACTICE IMPLICATIONS

As well as highlighting other potential needs during pregnancy and the ways in which they can be met, support from midwives has a key role. Through talking to women early in their pregnancy, signposting information and explaining ways to contact health professionals regarding informational or emotional support would fill a gap that currently is met by other aspects of their network.

Variability in multiple paternity rates for grey reef sharks (Carcharhinus amblyrhynchos) and scalloped hammerheads (Sphyrna lewini)

This study assessed the presence and prevalence of multiple paternity (MP) in litters of grey reef sharks (Carcharhinus amblyrhynchos) and scalloped hammerheads (Sphyrna lewini) opportunistically caught in Papua New Guinea (PNG). Litter size between species were significantly different with an average of 3.3 pups for grey reef sharks and 17.2 pups for scalloped hammerhead. Using 14 and 10 microsatellite loci respectively, we identified MP in 66% of grey reef sharks (4 out of 6 litters) and 100% MP in scalloped hammerheads (5 litters). We found high paternal skew (the uneven contribution of sires per litter) and a positive correlation between female adult size and litter size in scalloped hammerheads but not in grey reef sharks. Differences in the frequency of MP between species and the identification of paternal skew may be linked with mating strategies and post-copulatory mechanisms. Multiple paternity is thought to benefit populations by enhancing genetic diversity therefore increasing the population’s genetic resilience to extrinsic pressures. The identification of MP in two shark species reported here, further elucidates the complex breeding strategies elasmobranchs undertake.

BRAFV600E cooperates with CDX2 inactivation to promote serrated colorectal tumorigenesis

While 20–30% of colorectal cancers (CRCs) may arise from precursors with serrated glands, only 8–10% of CRCs manifest serrated morphology at diagnosis. Markers for distinguishing CRCs arising from ‘serrated’ versus ‘conventional adenoma’ precursors are lacking. We studied 36 human serrated CRCs and found CDX2 loss or BRAF mutations in ~60% of cases and often together (p=0.04). CDX2^Null/BRAF^V600E expression in adult mouse intestinal epithelium led to serrated morphology tumors (including carcinomas) and BRAF^V600E potently interacted with CDX2 silencing to alter gene expression. Like human serrated lesions, CDX2^Null/BRAF^V600E-mutant epithelium expressed gastric markers. Organoids from CDX2^Null/BRAF^V600E–mutant colon epithelium showed serrated features, and partially recapitulated the gene expression pattern in mouse colon tissues. We present a novel mouse tumor model based on signature defects seen in many human serrated CRCs – CDX2 loss and BRAF^V600E. The mouse intestinal tumors show significant phenotypic similarities to human serrated CRCs and inform about serrated CRC pathogenesis.

DOI:http://dx.doi.org/10.7554/eLife.20331.001

An integrated instrument for rapidly deforming living cells using rapid pressure pulses and simultaneously monitoring applied strain in near real time

Because many types of living cells are sensitive to applied strain, different in vitro models have been designed to elucidate the cellular and subcellular processes that respond to mechanical deformation at both the cell and tissue level. Our focus was to improve upon an already established strain system to make it capable of independently monitoring the deflection and applied pressure delivered to specific wells of a commercially available, deformable multiwell culture plate. To accomplish this, we devised a custom frame that was capable of mounting deformable 6 or 24 well plates, a pressurization system that could load wells within the plates, and a camera-based imaging system which was capable of capturing strain responses at a sufficiently high frame rate. The system used a user defined program constructed in Labview(®) to trigger plate pressurization while simultaneously allowing the deflection of the silicone elastomeric plate bottoms to be imaged in near real time. With this system, up to six wells could be pulsed simultaneously using compressed air or nitrogen. Digital image capture allowed near-real time monitoring of applied strain, strain rate, and the cell loading profiles. Although our ultimate goal is to determine how different strain rates applied to neurons modulates their intrinsic biochemical cascades, the same platform technology could be readily applied to other systems. Combining commercially available, deformable multiwell plates with a simple instrument having the monitoring capabilities described here should permit near real time calculations of stretch-induced membrane strain in multiple wells in real time for a wide variety of applications, including high throughput drug screening.

Topographical memory impairments after unilateral lesions of the anterior thalamus and contralateral inferotemporal cortex

Monkeys with crossed unilateral excitotoxic lesions of the anterior thalamus and unilateral inferotemporal cortex ablation were severely impaired at learning two tasks which required the integration of information about the appearance of objects and their positions in space. The lesioned monkeys were also impaired at learning a spatial task and a task which required the integration of information about the appearance of objects and the background on which the objects were situated. Monkeys with only one of the unilateral lesions were not impaired and previous work has shown that monkeys with bilateral lesions of the anterior thalamus were not impaired on these tasks. These results indicate that the whole of the inferotemporal cortex-anterior thalamic circuit, which passes via the hippocampus, fornix, mamillary bodies and mamillothalamic tract, is essential for the topographical analysis of information about specific objects in different positions in space. Together with previous work, the results show that a unilateral lesion may affect cognition in the presence of other brain damage when an equivalent bilateral lesion alone does not. The tasks required the slow acquisition of information into long term memory and therefore assessed semantic knowledge although other research has shown impairment on topographical processing within working or episodic memory following lesions of the hippocampal-diencephalic circuit. It is argued that the hippocampal-diencephalic circuit does not have a role in a specific form of memory such as episodic memory but rather is involved in topographical analysis of the environment in perception and across all types of declarative memory.

A resonance model gives the response to membrane potential for an ion channel: II. Simplification of the calculation, and prediction of stochastic resonance

In a previous communication (Green, 1998), the initial step in ion channel gating for voltage-gated channels was attributed to the tunneling of a proton between groups with similar p K values, under the influence of an electric field. This is in contrast to the standard thermally activated model, which leads to a "Boltzmann equation" for the gating current. In the paper that introduced the present model, the current-voltage curve was determined from a resonance effect, in which gating began when the local voltage crossed a threshold, causing a proton to tunnel to a new location. We have therefore investigated further the consequences of tunneling as the first step in gating; we find a method of improving the previous calculation. We also calculate a consequence of our model that has yet to be experimentally looked for, stochastic resonance. With gating a threshold process, one expects that such an effect should exist. Only a small effect is predicted by our calculation, but it may be detectable. If it is it would make possible the determination of important characteristics of the initiation of gating. For this reason it is worth determining the nature of the stochastic resonance to be expected. In addition, we have investigated further the possible ways of understanding our resonance model itself. The model assumes that not all channels have the same threshold, as local perturbations in the potential interfere. We therefore assume a Gaussian distribution of the thresholds, which is simpler than in the previous paper, in which a Gaussian gave inadequate results with the method used there. In this paper, we have reduced the number of parameters to two, and obtained the current-voltage curve, gating current, the response to a large sine wave (in the previous paper, the model was more complex), and stochastic resonance.

The ratio of ELR+ to ELR- CXC chemokines affects the lung and liver injury following hepatic ischemia/ reperfusion in the rat

Hepatic ischemia/reperfusion (I/R) results in a neutrophil-dependent lung and liver injury. The process of neutrophil recruitment and activation in this injury is at least partially dependent on the presence of the ELR+ CXC chemokines. Other investigations have shown that ELR- CXC chemokines can block ELR+ CXC chemokine neutrophil recruitment and activation in vitro. To begin to investigate the role of the balance between these 2 types of molecules in vivo in neutrophil recruitment and activation following hepatic I/R, we used our rat model of lobar hepatic I/R and pretreated animals with pharmacologic doses of gamma-interferon (gamma-IFN). gamma-IFN is known to upregulate some of the ELR- CXC chemokines, including gamma-IFN-inducible protein (IP-10) and monokine-induced by gamma-IFN (MIG), as well as down-regulate ELR+ CXC chemokine production. Following hepatic I/R or sham laparotomy, hepatic and pulmonary levels of the ELR- chemokines, IP-10 and MIG, and the ELR+ chemokines, rat cytokine-induced neutrophil chemoattractant (KC), macrophage inflammatory protein-2 (MIP-2), and epithelial neutrophil activating protein (ENA-78) were determined by ELISA, and lung and liver injury were assessed. In response to gamma-IFN, hepatic and pulmonary levels of the ELR- chemokines were increased and the levels of the ELR+ chemokines were decreased. Immunohistochemical staining confirmed the hepatocyte as the source of these molecules, as well as the changes in chemokine levels in response to gamma-IFN. There was an associated significant decrease in liver and lung injury, although there was no significant decrease in neutrophil influx in either tissue. This suggests that the alteration in the balance of ELR+ to ELR- CXC chemokines results in a decrease in tissue injury through a mechanism other than through an alteration in tissue neutrophil levels.

Cluster of diplopia cases after periocular anesthesia without hyaluronidase

PURPOSE

To describe a cluster of cases of iatrogenic diplopia after cataract surgery that occurred in 1998, when hyaluronidase was unavailable for use in periocular anesthetic regimens.

SETTING

The clinical practices of the authors.

METHODS

This study comprised a retrospective chart review.

RESULTS

Twenty-five cases of transient or permanent diplopia were reported. Of these, 13 eyes had retrobulbar and 10 had peribulbar injections; in 2 cases the injection technique was unknown. The inferior rectus was affected in 19 eyes; of these, 1 had a temporary palsy and 18 had permanent restriction. Temporary paresis developed in the lateral rectus in 5 cases and the superior rectus in 2. Eleven cases were submitted by 4 anterior segment surgeons, who collectively had a zero incidence of iatrogenic postoperative diplopia in the preceding 4 to 11 years of practice (approximately 6900 cases).

CONCLUSION

Hyaluronidase may be more important than previously suspected in preventing anesthetic-related damage to the extraocular muscles. The inferior rectus muscle is particularly vulnerable, presumably because of the injection technique.

Faculty evaluation in departments of family medicine: do our universities measure up?

Family medicine programmes at Canadian universities have expanded dramatically over the past several years. The development of effective means of faculty evaluation is a real concern for these departments as they strive to maintain the high quality of their teaching programmes in the face of rapid change. The literature on faculty evaluation, including reviews and articles discussing the application of faculty evaluations, is reviewed. The current state of faculty evaluation at three Canadian family medicine department has also been surveyed. Student evaluations were found to be valid, accurate and well studied. They are not perfect, however, and require the use of additional methods such as peer review or video review in conjunction in order to provide a comprehensive evaluation of all areas of faculty activity. Faculty evaluation in family medicine teaching units and community-based settings has not been well studied. Our survey of faculty evaluation at three Canadian universities shows much room for improvement, particularly in community-based settings where evaluation is almost non-existent. Expanding the use of faculty evaluations for formative means and linking evaluation to faculty development opportunities are essential if improvements to the currently used systems are to be successful and accepted by faculty. Special consideration must be given to community-based settings where systems designed for use in larger university settings will need to be modified substantially before they can be used effectively. Further research is required in this area.

A Resonance Model Gives the Response to Membrane Potential for an Ion Channel

The current-voltage curve for ion channels is perhaps the best known characteristic of these channels. One of the first properties measured, it is accurately known for a variety of channels. The curve is usually described by a single thermal activation energy, which is assumed to show the number of channels opening in response to a voltage step. Activation allows movement of charges as the membrane depolarizes; the putative number of charges moving to open the channel is a parameter estimated from the curve. As the activation energy, E, creates a probability dependent on exp(-E/kBT) (kBT=Boltzmann's constantxtemperature) for a given channel to reach the open state, the opening probability distribution is referred to as a Boltzmann curve. The Boltzmann calculation of the complete curve is consistent with the experimental results on the i-V curve. However, other experimental data are not so easily explained by a Boltzmann curve, and there exists an alternative. A calculation based on the assumption of a threshold potential, which, if passed, allows a channel to open, leads to an open probability vs. potential curve which is also consistent with the measured current vs. voltage curve over its entire voltage range. The calculation assumes fluctuations in the local environment, leading to a distribution of the potential at which channels cross the threshold. There is a physical mechanism which would account for such a threshold, tunneling of a proton as the mechanism of charge movement. Actually, two or more almost independent tunneling transitions are required to obtain agreement with experiment, but this changes no essential feature of the model. Because tunneling requires matching of energy levels in two wells, it is appropriately referred to as a resonance. This model also makes it possible to explain an additional experiment: Fohlmeister & Adelman (1985a, b, 1986) have shown that a sinusoidal potential added to the membrane potential produces second harmonics of the sinusoidal frequency in the output current. Similar response to a sinusoidal input is found from the model, and compared qualitatively to the published experimental results of Fohlmeister & Adelman. A time delay can also be introduced between reaching the threshold and channel opening, which is both physically necessary and necessary for agreement with experiment. Unlike the Boltzmann model, out model agrees (qualitatively) with their experiment. We have tested two distributions of state as a function of potential: Gaussian, and skewed Gaussian ( reverse similarV2 exp(-aV2), V=potential). The latter comes closer to representing both the open probability-potential curve and the Fohlmeister & Adelman results, although the pure Gaussian is still better than the Boltzmann model.Copyright 1998 Academic Press

Modulation of membrane currents and mechanical activity by niflumic acid in rat vascular smooth muscle

The effects of niflumic acid on whole-cell membrane currents and mechanical activity were examined in the rat portal vein. In freshly dispersed portal vein cells clamped at -60 mV in caesium (Cs+)-containing solutions, niflumic acid (1-100 microM) inhibited calcium (Ca2+)-activated chloride currents (IC1(Ca)) induced by caffeine (10 mM) and by noradrenaline (10 microM). In a potassium (K+)-containing solution and at a holding potential of - 10 mV, niflumic acid (10-100 microM) induced an outward K+ current (IK(ATP)) which was sensitive to glibenclamide (10-30 microM). At concentrations < 30 microM and at a holding potential of -2 mV, niflumic acid had no effect on the magnitude of the caffeine- or noradrenaline-stimulated current (IBK(Ca)) carried by the large conductance, Ca(2+)-sensitive K+ channel (BKCa). However, at a concentration of 100 microM, niflumic acid significantly inhibited IBK(Ca)) evoked by caffeine (10 mM) but not by NS1619 (1-(2'-hydroxy-5'-trifluoromethylphenyl)-5-trifluoromethyl-2(3 H) benzimidazolone; 20 microM). In Cs(+)-containing solutions, niflumic acid (10-100 microM) did not inhibit voltage-sensitive Ca2+ currents. In intact portal veins, niflumic acid (1-300 microM) inhibited spontaneous mechanical activity, an action which was partially antagonised by glibenclamide (1-10 microM), and contractions produced by noradrenaline (10 microM), an effect which was glibenclamide-insensitive. It is concluded that inhibition of ICl(Ca) and stimulation of IK(ATP) both contribute to the mechano-inhibitory actions of niflumic acid in the rat portal vein.

Pharmacological characterization of the inwardly-rectifying current in the smooth muscle cells of the rat bladder

1. In freshly-isolated single cells of the rat bladder detrusor, outwardly-rectifying and inwardly-rectifying membrane currents were identified by the whole-cell voltage-clamp technique. 2. The inwardly-rectifying current (IIR) exhibited features of a cation current permeable to both K+ and Na+ but it was unaffected by changes in extracellular Ca2+. It had an activation threshold close to -60 mV and an estimated reversal potential of -29 mV. 3. IIR activated slowly with a voltage-sensitive time-constant of 69 ms at -140 mV and 209 ms at -100 mV but did not exhibit time-dependent inactivation. 4. IIR was unaffected by tetraethylammonium (up to 20 mM) but it was reduced by extracellular Ba2+ (1 mM) and by extracellular Cs+ (1 mM). 5. IIR was reduced by terikalant (100 microM) and markedly inhibited by ciclazindol (100 microM) although at these concentrations, both agents also reduced outward currents. 6. IIR was inhibited by ZD7288 (10-100 microM) in a concentration-dependent manner. At concentrations up to 30 microM, ZD7288 did not reduce the magnitude of outward currents but these were inhibited by 100 microM ZD7288. 7. In strips of bladder detrusor, spontaneous mechanical activity was increased by ZD7288 (0.3-100 microM) and by ciclazindol (0.3-100 microM) but was unaffected by glibenclamide (1-10 microM). 8. It is concluded that IIR closely resembles the hyperpolarization-activated current Ih, previously described in the smooth muscle of rabbit jejunum and in a variety of other cell types. This current may play an important role in modulating detrusor excitability but this could not be confirmed using the inhibitors ZD7288 and ciclazindol.

Hepatic ischemia/reperfusion injury: importance of oxidant/tumor necrosis factor interactions

Previous studies have demonstrated a role for both tumor necrosis factor (TNF) and reactive oxygen intermediates (ROI) in hepatic ischemia/reperfusion (I/R) injury. Biologically active TNF was present in liver homogenates in ischemic and nonischemic lobes after 2 h of ischemia but without reperfusion. Using an in situ liver perfusion model, we measured ROI, TNF, and hepatic enzymes in the effluent after 2 h of ischemia. Increased reduction of ferricytochrome C was observed in the hepatic effluent, indicative of the formation of ROI. Treatment of animals with TNF neutralizing antisera significantly reduced both ROI and aspartate aminotransferase (AST). Animals treated with superoxide dismutase (SOD), or SOD + catalase (CAT) had greater TNF in the hepatic effluent compared with I/R alone; however, SOD or SOD + CAT did not cause additional release of AST.SOD + CAT plus anti-TNF serum resulted in significant protection compared with SOD + CAT plus control serum. Reperfusion of ischemic liver with 4 mM H2O2 increased both TNF and AST. Optimal protection of hepatocellular injury from reperfusion injury is achieved with a combination of antioxidants and inhibition of TNF.

Preretinal neovascularization in diabetic retinopathy: a preliminary investigation using contrast-enhanced magnetic resonance imaging

Preretinal neovascularization is a well-described feature of advanced diabetic retinopathy. In this study, contrast-enhanced magnetic resonance imaging was used to examine blood-retinal barrier breakdown associated with preretinal neovascularization in three subjects with proliferative diabetic retinopathy. Using a standard imaging protocol, a varying degree of vitreous enhancement was observed in these eyes. The location and severity of enhancement, judged by visual inspection of the images, corresponded to the fluorescein angiographic and/or clinical appearance of preretinal neovascularization. This result suggests that contrast-enhanced magnetic resonance imaging may prove a reasonable approach to the identification of preretinal neovascularization in eyes with significant media opacities.

Monte Carlo simulation of the water in a channel with charges

A Monte Carlo simulation of water in a channel with charges suggests the existence of water in immobile, high density, essentially glasslike form near the charges. The channel model has a conical section with an opening through which water molecules can pass, at the narrow end of the cone, and a cylindrical section at the other end. When the charges are placed near the narrow section of the model, the "glass" effectively blocks the channel; with the charges removed, the channel opens. The effect can be determined from the rate of passage of the water molecules through the pore, from the average orientation of the water molecule, and from distortion of the distribution of molecules. In the simulations carried out to date, no external ions have been considered. In addition to the energy, the Helmholtz free energy has been calculated.

Genetic and fine structure analysis of unc-26(IV) and adjacent regions in Caenorhabditis elegans

The genetic organization of unc-26(IV) and adjacent regions was studied in Caenorhabditis elegans. We constructed a fine structure genetic map of unc-26(IV), a gene that affects locomotion and pharyngeal muscle movement but not muscle structure. Eleven alleles were positioned relative to each other recombinationally and were classified according to phenotypic severity. The unc-26 gene spans at least 0.026 map units, which is exceptionally large for a C. elegans gene. All but one allele, e205, are amorphic alleles. Interestingly, e205 is hypomorphic but also suppressible by the amber suppressor sup-7. Nineteen lethal mutations in the unc-26 region were isolated and characterized. The unc-26 region is subdivided into four zones by five deficiency breakpoints. These mutations fall into 15 complementation groups. The stages of development affected by these mutations were determined.

Electrorheological effects and gating of membrane channels

A hypothesis is presented on the gating of ion channels. This is considered as a consequence, in part, of a large increase in viscosity of the water in the "vestibule" region of the channel in the high field present when the channel is not conducting. This part of gating amounts to "melting" of the high viscosity part of the water upon release of the field. The resulting model accounts qualitatively for a number of phenomena in the literature, including the steepness of the voltage dependence of gating, the slowing of gating upon substitution of D2O for H2O, and the pressure dependence of the gating kinetics. The viscosity increase with field is well known in the literature; several forms of electroviscous effects, a viscoelectric effect, and a generalized electrorheological effect have been described. This model appears closest to an electrorheological effect in which boundary water out to a few molecular diameters is structured in the presence of a high field, while the boundary (here, protein) moves. The size of the channel entrance is small enough for this effect to prevent conductivity. The remainder of the gating current, which occurs at more polarized potentials, is attributed to protein motion. Some consequences of the model are discussed. Qualitative comparison with published data is included.

Diffusion and 1/f noise

The noise associated with ion transport through porous membranes is considered as a diffusion process. This is confirmed experimentally by measuring the noise spectra associated with pores of known dimension. It is then shown that one dimensional diffusion through pores of variable length can produce approximate 1/f noise spectra, if the distribution of lengths is proportional to (length)-1.