The plakin domain of C. elegans VAB-10/plectin acts as a hub in a mechanotransduction pathway to promote morphogenesis

Mechanical forces can elicit a mechanotransduction response through junction-associated proteins. In contrast to the wealth of knowledge available for focal adhesions and adherens junctions, much less is known about mechanotransduction at hemidesmosomes. Here, we focus on the C. elegans plectin homolog VAB-10A, the only evolutionary conserved hemidesmosome component. In C. elegans, muscle contractions induce a mechanotransduction pathway in the epidermis through hemidesmosomes. We used CRISPR to precisely remove spectrin repeats (SRs) or a partially hidden Src homology 3 (SH3) domain within the VAB-10 plakin domain. Deleting the SH3 or SR8 domains in combination with mutations affecting mechanotransduction, or just the part of SR5 shielding the SH3 domain, induced embryonic elongation arrest because hemidesmosomes collapse. Notably, recruitment of GIT-1, the first mechanotransduction player, requires the SR5 domain and the hemidesmosome transmembrane receptor LET-805. Furthermore, molecular dynamics simulations confirmed that forces acting on VAB-10 could make the central SH3 domain, otherwise in contact with SR4, available for interaction. Collectively, our data strongly indicate that the plakin domain plays a central role in mechanotransduction and raise the possibility that VAB-10/plectin might act as a mechanosensor.

Sensor space group analysis for fNIRS data

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is a method for monitoring hemoglobin responses using optical probes placed on the scalp. fNIRS spatial resolution is limited by the distance between channels defined as a pair of source and detector, and channel positions are often inconsistent across subjects. These challenges can lead to less accurate estimate of group level effects from channel-specific measurements.

NEW METHOD

This paper addresses this shortcoming by applying random-effects analysis using summary statistics to interpolated fNIRS topographic images. Specifically, we generate individual contrast images containing the experimental effects of interest in a canonical scalp surface. Random-effects analysis then allows for making inference about the regionally specific effects induced by (potentially) multiple experimental factors in a population.

RESULTS

We illustrate the approach using experimental data acquired during a colour-word matching Stroop task, and show that left frontopolar regions are significantly activated in a population during Stroop effects. This result agrees with previous neuroimaging findings.

COMPARED WITH EXISTING METHODS

The proposed methods (i) address potential misalignment of sensor locations between subjects using spatial interpolation; (ii) produce experimental effects of interest either on a 2D regular grid or on a 3D triangular mesh, both representations of a canonical scalp surface; and (iii) enables one to infer population effects from fNIRS data using a computationally efficient summary statistic approach (random-effects analysis). Significance of regional effects is assessed using random field theory.

CONCLUSIONS

In this paper, we have shown how fNIRS data from multiple subjects can be analysed in sensor space using random-effects analysis.

RAL-1 controls multivesicular body biogenesis and exosome secretion

Exosomes are secreted vesicles arising from the fusion of multivesicular bodies (MVBs) with the plasma membrane. Despite their importance in various processes, the molecular mechanisms controlling their formation and release remain unclear. Using nematodes and mammary tumor cells, we show that Ral GTPases are involved in exosome biogenesis. In Caenorhabditis elegans, RAL-1 localizes at the surface of secretory MVBs. A quantitative electron microscopy analysis of RAL-1-deficient animals revealed that RAL-1 is involved in both MVB formation and their fusion with the plasma membrane. These functions do not involve the exocyst complex, a common Ral guanosine triphosphatase (GTPase) effector. Furthermore, we show that the target membrane SNARE protein SYX-5 colocalizes with a constitutively active form of RAL-1 at the plasma membrane, and MVBs accumulate under the plasma membrane when SYX-5 is absent. In mammals, RalA and RalB are both required for the secretion of exosome-like vesicles in cultured cells. Therefore, Ral GTPases represent new regulators of MVB formation and exosome release.

Characteristics of diet patterns in metabolically obese, normal weight adults (Korean National Health and Nutrition Examination Survey III, 2005)

BACKGROUND AND AIMS

Metabolically obese normal weight (MONW) subjects are a subgroup of individuals who have a normal weight and body mass index (BMI), but exhibit obesity-related abnormalities. The objective of this study was to analyze the prevalence of metabolic syndrome (MetS) and characteristics of diet patterns in MONW Koreans.

METHODS AND RESULTS

We analyzed the data of 3050 adults > 20 years of age with a normal BMI (18.5~24.9 kg/m(2)) obtained from the Korea National Health and Nutrition Examination Survey III. Anthropometric measurements and information on health behaviors were obtained. The diagnostic criteria for MetS were defined by the International Diabetes Federation consensus. Dietary intake was assessed by the 24-h recall method. The weighted prevalence of MONW was 14.3%. The risk of MONW correlated inversely with the frequency of snacking and positively with the type of snack, particularly those with high carbohydrates. A high carbohydrate diet (≥73.9% of energy intake) compared to a low carbohydrate diet (<59.9% of energy intake) was positively associated with the risk of MONW (OR = 2.54; 95% CI: 1.41, 4.56), whereas a high protein diet (≥17.1% of energy intake) compared to a low protein diet (<12.2% of energy intake) reduced the risk of MONW (OR = 0.60; 95% CI: 0.39, 0.92) in females, but not in males.

CONCLUSIONS

This study suggests that a reduced intake of carbohydrates and carbohydrate snacks were associated with a lower prevalence of MONW in females.

Estimation of compressive forces on lumbar spine from categorical posture data

To combine estimates of trunk posture and force into an integrated measure of load on the low back, continuous variables for body angles were estimated by assuming specified distributions within corresponding posture categories with Monte-Carlo (MC) simulation. The estimated posture angles were compared with reference measurements from the Lumbar Motion Monitor and inclinometers. The lumbar compression estimates, generated from simulated posture angles and from direct measurement, were compared. Trunk flexion showed high correlation between direct measurements and simulated angles, as did L5/S1 compression. The MC approach to extracting continuous posture angles from categorized observations did not appear to introduce large error in the variables used to estimate spinal compressive forces. When instrumentation methods of postural assessment are not feasible, a simulation approach combined with biomechanical modelling could be used to integrate multiple external exposure variables into estimates of compressive forces acting on the low back.

Haemoptysis in patients with a normal chest radiograph: bronchoscopy-CT correlation

The exact role of fibre-optic bronchoscopy (FOB) and CT of the chest in the diagnosis of patients presenting with haemoptysis and a normal or non-localizing chest radiograph has not been clearly defined. A study was designed to evaluate 50 patients presenting with haemoptysis and a normal or non-localizing chest radiograph using FOB and high-resolution computed tomography (HRCT). A definitive diagnosis was established in 17 (34%) patients. The aetiologies included bronchiectasis (24%), bronchial adenoma (6%), tuberculosis (2%) and bronchitis (2%). The diagnosis was made by HRCT in 15 (30%) patients, while FOB was diagnostic in five (10%) patients. The diagnosis was made by HRCT and FOB in all patients with focal airway abnormalities. Therefore, HRCT effectively delineated abnormalities of both the central and peripheral airways. It is concluded that CT should be obtained prior to FOB in all patients presenting with haemoptysis and a normal or non-localizing chest radiograph.

Intervention classifications for nursing practice and the ICNP: cultural considerations for Korean nurses

There are several intervention classifications for nursing practice. Yet, their relevancy and clarity for international use has not been evaluated. Thus, the paper presents a review of 4 major nursing intervention classifications (Saba's Home Health Care Classifications, Omaha's Intervention Scheme, Grobe's Nursing Intervention Lexicon & Taxonomy, and the International Classification for Nursing Practice) for Korean nursing practice. A simple comparison procedure utilized to determine the relevancy and clarity of each overall scheme and specific elements. The findings showed that general concepts for the top level of all the classifications were both relevant and clear. However, specific elements of lower levels became less clear and relevant because of the lack of definitions and cultural differences. In particular, interventions related to psycho-social and environmental components appeared to be either unclear or non-relevant for Korean nursing practice while interventions related to physiological components were found to be very relevant and clear. In conclusion, multiple levels of hierarchical intervention schemes and the absence of definitions impede clarity of intervention classifications. In addition, for international use, an intervention classification needs to be sensitive to cultural relevancy in its elements.