Neuronal Small RNAs Control Behavior Transgenerationally.

It is unknown whether the activity of the nervous system can be inherited. In Caenorhabditis elegans nematodes, parental responses can transmit heritable small RNAs that regulate gene expression transgenerationally. In this study, we show that a neuronal process can impact the next generations. Neurons-specific synthesis of RDE-4-dependent small RNAs regulates germline amplified endogenous small interfering RNAs (siRNAs) and germline gene expression for multiple generations. Further, the production of small RNAs in neurons controls the chemotaxis behavior of the progeny for at least three generations via the germline Argonaute HRDE-1. Among the targets of these small RNAs, we identified the conserved gene saeg-2, which is transgenerationally downregulated in the germline. Silencing of saeg-2 following neuronal small RNA biogenesis is required for chemotaxis under stress. Thus, we propose a small-RNA-based mechanism for communication of neuronal processes transgenerationally.

Evaluation of ImpENSA technology-enabled behaviour change module delivered to healthcare professionals in South Africa to improve micronutrient nutrition during the first 1000 days.

Healthcare professionals (HCPs) have vital roles in providing evidence-based care to promote healthy micronutrient nutrition in early life. Providing such care requires scalable training to strengthen knowledge and confident application of effective behaviour change skills. Among 33 public and private HCPs (primarily dietitians) in South Africa, we evaluated the behaviour change aspects of a technology-enabled National Qualification Sub-Framework level 6 programme, Improving Early Nutrition and Health in South Africa ('ImpENSA'). This programme comprises two self-directed micronutrient and behaviour change knowledge-based eLearning and one facilitated online practical skills modules to improve maternal and infant micronutrient nutrition. Using assessments, questionnaires and interviews, we collected data at baseline, after module completion and at 3-month follow-up after programme completion. Questionnaire and interview data showed major improvements in understanding of and attitudes towards person-centred behaviour change support immediately following the eLearning module on behaviour change. The assessment pass rate increased from 38% at baseline to 88% postmodule, demonstrating significant knowledge gain in behaviour change support. Intention to change practice towards a person-centred approach was high and many had already started implementing changes. Three months postprogramme, support was centred around patients' needs. Open relationships with patients, improved patient outcomes and increased job satisfaction were among reported outcomes. Many reported becoming better change facilitators and reflective practitioners. Additional improvements in understanding and attitudes to behaviour change support were evident, reinforced by making changes and experiencing positive outcomes. The findings suggest that technology-enabled learning can equip HCPs with knowledge and skills to effectively support behaviour change for healthy micronutrient nutrition during pregnancy and infancy.

Are gender gaps due to evaluations of the applicant or the science? A natural experiment at a national funding agency.

BACKGROUND: Across countries and disciplines, studies show male researchers receive more research funding than their female peers. Because most studies have been observational, it is unclear whether imbalances stem from evaluations of female research investigators or of their proposed research. In 2014, the Canadian Institutes of Health Research created a natural experiment by dividing investigator-initiated funding applications into two new grant programmes: one with and one without an explicit review focus on the calibre of the principal investigator. METHODS: We analysed application success among 23 918 grant applications from 7093 principal investigators in all investigator-initiated Canadian Institutes of Health Research grant programmes between 2011 and 2016. We used generalised estimating equations to account for multiple applications by the same applicant and compared differences in application success between male and female principal investigators under different review criteria. FINDINGS: Overall application success across competitions was 15·8%. After adjusting for age and research domain, the predicted probability of success in traditional programmes was 0·9 percentage points lower for female applicants than male applicants (95% CI 2·0 lower-0·2 higher; odds ratio 0·934, 95% CI 0·854-1·022). In the new programme, in which review focused on the proposed science, the gap remained 0·9 percentage points (3·2 lower-1·4 higher; 0·998, 0·794-1·229). In the new programme with an explicit review focus on the calibre of the principal investigator, the gap was 4·0 percentage points (6·7 lower-1·3 lower; 0·705, 0·519-0·960). INTERPRETATION: Gender gaps in grant funding are attributable to less favourable assessments of women as principal investigators, not of the quality of their proposed research. We discuss reasons less favourable assessments might occur and strategies to foster fair and rigorous peer review. FUNDING: None.

Compartmentalized calcium dynamics in a C. elegans interneuron encode head movement.

The confinement of neuronal activity to specific subcellular regions is a mechanism for expanding the computational properties of neurons. Although the circuit organization underlying compartmentalized activity has been studied in several systems, its cellular basis is still unknown. Here we characterize compartmentalized activity in Caenorhabditis elegans RIA interneurons, which have multiple reciprocal connections to head motor neurons and receive input from sensory pathways. We show that RIA spatially encodes head movement on a subcellular scale through axonal compartmentalization. This subcellular axonal activity is dependent on acetylcholine release from head motor neurons and is simultaneously present and additive with glutamate-dependent globally synchronized activity evoked by sensory inputs. Postsynaptically, the muscarinic acetylcholine receptor GAR-3 acts in RIA to compartmentalize axonal activity through the mobilization of intracellular calcium stores. The compartmentalized activity functions independently of the synchronized activity to modulate locomotory behaviour.

The feasibility of implementing food-based dietary guidelines in the South African primary-school curriculum.

OBJECTIVE: To explore the perceptions of educators from the Western Cape Province about the feasibility of implementing South African food-based dietary guidelines (FBDG) in the national curriculum of primary schools. DESIGN: Combined quantitative and qualitative methods. We report on the quantitative component. SETTING: Twelve public primary schools of different socio-economic status in three education districts of the Western Cape: Metro Central, Metro East and Cape Winelands. SUBJECTS: Educators (n 256) participated in the self-completed questionnaire survey. RESULTS: Educators assessed that FBDG were appropriate to South African schoolchildren (94%), could be used as an education tool (97%) and fill gaps in the current curriculum about healthy dietary habits (91%). Besides Life Orientation, FBDG could be taught in other learning areas from grades 3 to 7 (9-13 years old). Important barriers to implementing FBDG in the curriculum were educators' workload (61%), insufficient time (46%), learners' disadvantaged background (43%) and educators' lack of knowledge (33%). Other approaches to teach children about FBDG included linking these to the National School Nutrition Programme (82%), school tuck shops (79%), parent meetings (75%), school nutrition policy (73%) and school assembly (57%). Educators in high-income schools perceived that learners' lifestyle was significantly worse (P < 0·001) and that tuck shops and the school assembly were the best means to teach pupils about FBDG (P < 0·001 and P < 0·05). CONCLUSIONS: Implementing FBDG in the national school curriculum is seen as important together with optimizing the school physical environment. Key factors required for successful implementation in the curriculum are sufficient educational materials, adequate time allocation and appropriate educator training.

CARDIAN: a novel computational approach for real-time end-diastolic frame detection in intravascular ultrasound using bidirectional attention networks.

Introduction: Changes in coronary artery luminal dimensions during the cardiac cycle can impact the accurate quantification of volumetric analyses in intravascular ultrasound (IVUS) image studies. Accurate ED-frame detection is pivotal for guiding interventional decisions, optimizing therapeutic interventions, and ensuring standardized volumetric analysis in research studies. Images acquired at different phases of the cardiac cycle may also lead to inaccurate quantification of atheroma volume due to the longitudinal motion of the catheter in relation to the vessel. As IVUS images are acquired throughout the cardiac cycle, end-diastolic frames are typically identified retrospectively by human analysts to minimize motion artefacts and enable more accurate and reproducible volumetric analysis. Methods: In this paper, a novel neural network-based approach for accurate end-diastolic frame detection in IVUS sequences is proposed, trained using electrocardiogram (ECG) signals acquired synchronously during IVUS acquisition. The framework integrates dedicated motion encoders and a bidirectional attention recurrent network (BARNet) with a temporal difference encoder to extract frame-by-frame motion features corresponding to the phases of the cardiac cycle. In addition, a spatiotemporal rotation encoder is included to capture the IVUS catheter's rotational movement with respect to the coronary artery. Results: With a prediction tolerance range of 66.7 ms, the proposed approach was able to find 71.9%, 67.8%, and 69.9% of end-diastolic frames in the left anterior descending, left circumflex and right coronary arteries, respectively, when tested against ECG estimations. When the result was compared with two expert analysts' estimation, the approach achieved a superior performance. Discussion: These findings indicate that the developed methodology is accurate and fully reproducible and therefore it should be preferred over experts for end-diastolic frame detection in IVUS sequences.

Observing and Quantifying Fluorescent Reporters.

Genetically encoded fluorescent reporters take advantage of C. elegans' transparency to allow non-invasive, in vivo observation, and recording of physiological processes in intact animals. Here, we discuss the basic microscope components required to observe, image, and measure fluorescent proteins in live animals for students and researchers who work with C. elegans but have limited experience with fluorescence imaging and analysis.

Machine learning for atherosclerotic tissue component classification in combined near-infrared spectroscopy intravascular ultrasound imaging: Validation against histology.

BACKGROUND AND AIMS: Accurate classification of plaque composition is essential for treatment planning. Intravascular ultrasound (IVUS) has limited efficacy in assessing tissue types, while near-infrared spectroscopy (NIRS) provides complementary information to IVUS but lacks depth information. The aim of this study is to train and assess the efficacy of a machine learning classifier for plaque component classification that relies on IVUS echogenicity and NIRS-signal, using histology as reference standard. METHODS: Matched NIRS-IVUS and histology images from 15 cadaveric human coronary arteries were analyzed (10 vessels were used for training and 5 for testing). Fibrous/pathological intimal thickening (F-PIT), early necrotic core (ENC), late necrotic core (LNC), and calcific tissue regions-of-interest were detected on histology and superimposed onto IVUS frames. The pixel intensities of these tissue types from the training set were used to train a J48 classifier for plaque characterization (ECHO-classification). To aid differentiation of F-PIT from necrotic cores, the NIRS-signal was used to classify non-calcific pixels outside yellow-spot regions as F-PIT (ECHO-NIRS classification). The performance of ECHO and ECHO-NIRS classifications were validated against histology. RESULTS: 262 matched frames were included in the analysis (162 constituted the training set and 100 the test set). The pixel intensities of F-PIT and ENC were similar and thus these two tissues could not be differentiated by echogenicity. With ENC and LNC as a single class, ECHO-classification showed good agreement with histology for detecting calcific and F-PIT tissues but had poor efficacy for necrotic cores (recall 0.59 and precision 0.29). Similar results were found when F-PIT and ENC were treated as a single class (recall and precision for LNC 0.78 and 0.33, respectively). ECHO-NIRS classification improved necrotic core and LNC detection, resulting in an increase of the overall accuracy of both models, from 81.4% to 91.8%, and from 87.9% to 94.7%, respectively. Comparable performance of the two models was seen in the test set where the overall accuracy of ECHO-NIRS classification was 95.0% and 95.5%, respectively. CONCLUSIONS: The combination of echogenicity with NIRS-signal appears capable of overcoming limitations of echogenicity, enabling more accurate characterization of plaque components.

C. elegans does a spit take.

Eating can turn into spitting because individual parts of a muscle cell are able to contract in different ways.

Three-Dimensional Fruit Tissue Habitats for Culturing Caenorhabditis elegans.

Environmental factors influence many traits of biological interest, but reproducing an animal's natural habitat in a controlled laboratory environment is challenging. Environmental enrichment-adding complexity to the usually simplistic conditions under which laboratory animals are raised-offers a potential tool for better understanding biological traits while maintaining controlled laboratory conditions. For the model nematode Caenorhabditis elegans, the contrast between the natural environment and the laboratory conditions in which they are raised is enormous. Although several methods have been developed in an effort to complexify C. elegans laboratory conditions, there is still a need for an enriched controlled laboratory habitat in which C. elegans can be raised over several generations, the bacterial food availability is similar to that in traditional agar plates, and the animals are crawling as opposed to swimming or burrowing. To this end, we describe here a standardized protocol for creating controlled, reproducible, three-dimensional environments for multigenerational maintenance of C. elegans in the laboratory. These environments are derived from decellularized apple hypanthium tissue and have bacterial food uniformly distributed throughout. We also describe how traditional C. elegans methods of collecting synchronized eggs, cleaning contaminated stocks, and collecting animal populations are adapted to our scaffold environment. These methods can be adapted to host different bacteria or bacterial populations, and the resulting scaffolds can be used in a range of experimental designs for behavioral and phenotypical studies in C. elegans and other nematodes. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Decellularization and storage of apple tissue Basic Protocol 2: Preparation of plates from decellularized apple scaffolds Basic Protocol 3: Synchronization of eggs or animals and cleaning contaminated stocks from scaffold plates Alternate Protocol: Collection of non-synchronized larvae and adults from scaffold plates.

A three-dimensional habitat for C. elegans environmental enrichment.

As we learn more about the importance of gene-environment interactions and the effects of environmental enrichment, it becomes evident that minimalistic laboratory conditions can affect gene expression patterns and behaviors of model organisms. In the laboratory, Caenorhabditis elegans is generally cultured on two-dimensional, homogeneous agar plates abundantly covered with axenic bacteria culture as a food source. However, in the wild, this nematode thrives in rotting fruits and plant stems feeding on bacteria and small eukaryotes. This contrast in habitat complexity suggests that studying C. elegans in enriched laboratory conditions can deepen our understanding of its fundamental traits and behaviors. Here, we developed a protocol to create three-dimensional habitable scaffolds for trans-generational culture of C. elegans in the laboratory. Using decellularization and sterilization of fruit tissue, we created an axenic environment that can be navigated throughout and where the microbial environment can be strictly controlled. C. elegans were maintained over generations on this habitat, and showed a clear behavioral bias for the enriched environment. As an initial assessment of behavioral variations, we found that dauer populations in scaffolds exhibit high-frequency, complex nictation behavior including group towering and jumping behavior.

PHR regulates growth cone pausing at intermediate targets through microtubule disassembly.

Axonal growth cones use intermediate targets to navigate in the developing nervous system. Encountering these sites is correlated with growth cone pausing. PHR (Phr1, Esrom, Highwire, RPM-1) is a large neuronal ubiquitin ligase that interacts with multiple signaling pathways. Mouse and zebrafish phr mutants have highly penetrant axon pathfinding defects at intermediate targets. Mouse phr mutants contain excessive microtubules in the growth cone, which has been attributed to upregulation of DLK/p38 signaling. Here, we ask whether this pathway and microtubule misregulation are indeed linked to guidance errors in the vertebrate brain, using the zebrafish. By live imaging, we show that loops form when microtubules retract without depolymerizing. JNK, but not p38, phosphorylation is increased in mutant growth cones. However microtubule looping cannot be suppressed by inhibiting JNK. The phr microtubule defect can be phenocopied by taxol, while microtubule destabilization in vitro using nocodazole prevents loop formation. Acute disruption in vivo with nocodazole suppresses the intermediate target guidance defect. Given that microtubule looping is associated with growth cone pausing, we propose that microtubule disassembly, mediated by PHR, is essential for exiting the paused state at intermediate targets.

Lead Toxicity in Children: An Unremitting Public Health Problem.

BACKGROUND: Lead is a pervasive environmental contaminant. Lead accumulates in the body, impairing a molecular level various cellular processes. Lead exposure during childhood causes adverse and permanent neurodevelopmental consequences, sometimes even with "low" blood lead levels. Symptoms are frequently silent, making lead exposure an often unrecognized and underestimated threat for pervasive neurocognitive disorders. METHODS: We identified articles focusing on childhood exposure to lead and neurodevelopment via a search of the electronic database PubMed (National Library of Medicine), including journal articles published from 2007 to 2019. These articles were used to evaluate the effect of environmental lead exposure and analyze whether control efforts over the past decades have altered the prevalence of exposed children. CONCLUSIONS: Children are still being exposed to lead despite evidence of the adverse impact of exposure, even for children with blood lead levels below the currently recognized threshold for intervention. Legislative and educational efforts have reduced lead exposure but are not being followed universally. Primary prevention and identification of high-risk populations are the best cost-benefit interventions to fight this public health problem.

Increased radiation dose to overweight and obese patients from radiographic examinations.

PURPOSE: To estimate the increase in effective radiation dose from diagnostic x-rays for overweight and obese adult patients, as compared with the effective dose for lean reference phantoms. MATERIALS AND METHODS: Relative effective radiation doses (E/E(0)) for the acquisition of chest and abdominal radiographs were calculated by using Monte Carlo computer simulations of effective doses delivered to adult phantoms with (E) and without (E(0)) subcutaneous adipose tissue added to the torso for five fat distributions. Total (anterior plus posterior) fat thicknesses ranged from 0 to 38 cm. RESULTS: For 30 cm of additional fat, E/E(0) values for 120-kVp chest and 80-kVp abdomen radiographs ranged from approximately 2 to 31 and 2 to 83 for male patients, respectively, and from 2 to 45 and 2 to 76 for female patients, respectively, depending on the type of fat distribution and patient orientation in the x-ray beam (anteroposterior or posteroanterior). Orienting the patient such that the thinnest fat layer was facing away from the x-ray tube minimized E/E(0), which was well approximated by using the formula E/E(0) = [B(t)/B(0)] x exp(kt(DF)), where B(t) and B(0) are the antiscatter grid Bucky factors for patient thicknesses of t and t = 20 cm, respectively; k, a constant; and t(DF), the distal (beam exit) fat layer thickness. Reductions in E/E(0) reached 14% and 20% for the thickest phantoms when x-ray tube voltages were increased by 10 and 20 kVp, respectively, for abdominal radiography in the male phantom. CONCLUSION: Effective doses from radiographic examinations in the extremely obese can exceed 100 mSv from only a small number of abdominal examinations and should be minimized to the extent possible and monitored. Exponential dose increases for increased subcutaneous fat thicknesses can be reduced substantially by positioning the patient so that the thinnest fat layer (anterior or posterior) is closest to the image receptor. Increasing the tube voltage also reduces the dose-but to a much smaller extent.

Predictive factors for in-stent late loss and coronary lesion progression in patients with type 2 diabetes mellitus randomized to rosiglitazone or placebo.

BACKGROUND: Type 2 diabetics (DM2) are at increased risk for restenosis as well as nonculprit coronary artery lesion (NCCL) progression. Rosiglitazone (RSG) favorably modifies many of the altered biologic processes in DM2, although recent reports have questioned its safety. We conducted a double-blind randomized trial to assess the effects of RSG versus placebo on in-stent late lumen loss (LL) and angiographic progression of NCCL. METHODS: A total of 65 DM2 were randomized to RSG (4 mg/d) (n = 32) or placebo (n = 33) at the time of stenting and underwent clinical and laboratory analysis at 1 and 4 months and 8-month angiography (n = 46 patients). Rapid angiographic progression (RAP) was defined as > or =20% diameter reduction of preexisting NCCL by quantitative coronary angiography, or a new narrowing > or =30%. RESULTS: Mean LL in RSG (n = 33 lesions) was not different from that of placebo (0.62 +/- 0.59 vs 0.70 +/- 0.67, P = NS). Seven (13.5%) of 52 NCCLs have RAP in RSG versus 9 (16.1%) of 56 in placebo (P = NS). High-sensitivity C-reactive protein (hs-CRP) was the only predictor of RAP. Patients with a 120-day hs-CRP > or =75th percentile had an OR of 7.35 (95% CI 2.35-23) for RAP versus those below. Although RSG treatment also lowered log (hs-CRP) at 4 months (RSG 0.10 +/- 0.37 vs placebo 0.26 +/- 0.49, P = .06), it did not decrease the likelihood of plaque progression while also raising LDL and N-terminal brain naturetic peptide. CONCLUSIONS: Rosiglitazone appears not to lower LL or reduce angiographic progression of NCCL in DM2 and had complex effects on markers of cardiac risk.

Environmental Programming of Adult Foraging Behavior in C. elegans.

Foraging strategies should be tuned to the expected distribution of resources in the environment. Tuning can occur over generations and lead to genetic differences in innate foraging behavior or over shorter timescales within an individual's lifespan. Both genetically encoded and experience-based strategies are implemented by neural circuits that respond to environmental cues and track internal states. Caenorhabditis elegans exhibit both between-strain genetic differences and within-strain plasticity in foraging. In individuals, changes in foraging are usually short term and based on recent experience. Here, we tested whether developmental experience could permanently alter foraging. We found that, in most wild strains, early-life starvation led to "cautious" foraging strategies, in which exploration is reduced, and these behavioral changes are associated with altered dynamics in a locomotory circuit. Possessing either the derived (domestication-associated) or ancestral allele of the neuroglobin glb-5 determines foraging plasticity. Overall, we show that C. elegans exhibit adaptive developmental plasticity that affects multiple aspects of foraging behavior and leads to changes in a core navigation circuit and that innate foraging traits and plasticity in those traits are genetically separable. VIDEO ABSTRACT.

Gender differences in spatial navigation: Characterizing wayfinding behaviors.

Men show a consistent spatial navigation advantage over women, which is often attributed to their increased use of survey spatial strategies. But what about men's navigation gives them an advantage? One possibility is that the way in which men explore environments is fundamentally different, leading to better navigational performance. To test this possibility, this study investigated whether there are gender differences in wayfinding behaviors during navigation that relate to navigational success in a real-world, large-scale, unconstrained navigation task. West Point cadets were given a masked GPS tracker and sent into a large-scale, natural environment to locate targets indicated on maps. We assessed how they explored the environment by computing three measures from the GPS tracks and related these measures to their ability to find the assigned target locations. We also tested whether their self-reported spatial ability related to navigational success. Results showed that males performed better than females, which replicates prior work. Further, traveling longer distances without changing course, pausing less, and fewer returns to previously visited locations were significantly related to the ability to locate the correct target. Consistent with full mediation, the significant relationship between gender and navigational success is fully accounted for by men and women producing different wayfinding behaviors, which in turn predict differences in navigational success. Further, there was no unique relationship between self-reported spatial skills and navigational success. This study is a first step toward showing the relationship between gender, wayfinding behaviors, and navigational success in a natural, real-world navigation task.

A Gate-and-Switch Model for Head Orientation Behaviors in Caenorhabditis elegans.

The nervous system seamlessly integrates perception and action. This ability is essential for stable representation of and appropriate responses to the external environment. How the sensorimotor integration underlying this ability occurs at the level of individual neurons is of keen interest. In Caenorhabditis elegans, RIA interneurons receive input from sensory pathways and have reciprocal connections with head motor neurons. RIA simultaneously encodes both head orientation and sensory stimuli, which may allow it to integrate these two signals to detect the spatial distribution of stimuli across head sweeps and generate directional head responses. Here, we show that blocking synaptic release from RIA disrupts head orientation behaviors in response to unilaterally presented stimuli. We found that sensory encoding in RIA is gated according to head orientation. This dependence on head orientation is independent of motor encoding in RIA, suggesting a second, posture-dependent pathway upstream of RIA. This gating mechanism may allow RIA to selectively attend to stimuli that are asymmetric across head sweeps. Attractive odor removal during head bends triggers rapid head withdrawal in the opposite direction. Unlike sensory encoding, this directional response is dependent on motor inputs to and synaptic output from RIA. Together, these results suggest that RIA is part of a sensorimotor pathway that is dynamically regulated according to head orientation at two levels: the first is a gate that filters sensory representations in RIA, and the second is a switch that routes RIA synaptic output to dorsal or ventral head motor neurons.

Asymmetric innervation of the habenula in zebrafish.

The habenular complex is a paired structure found in the diencephalon of all vertebrates, linking the forebrain and midbrain. Habenulae are asymmetrical and may contribute to lateralized behavior. Recent studies in zebrafish have characterized molecular pathways that give rise to the habenular asymmetry and the distinct projections of the left and right habenula to the midbrain. However, it is unclear whether there are asymmetries in habenula afferents from the forebrain. By lipophilic dye tracing, we find that axons innervating the habenula derive primarily from a region in the lateral diencephalon containing migrated neurons of the eminentia thalami (EmT). EmT neurons terminate in neuropils in both ipsilateral and contralateral habenula. These axons, together with axons from migrated neurons of the posterior tuberculum and pallial neurons, cross the midline via the habenular commissure. Subsets of pallial neurons terminate only in the medial right habenula, regardless of which side of the brain they originate from. These include an unusual type of forebrain projection: axons that cross the midline twice, at both the anterior and habenular commissures. Our data establish that there is asymmetric innervation of the habenula from the telencephalon, suggesting a mechanism by which habenula asymmetry might contribute to lateralized behavior.