Allosteric Regulation of Human Plastins

Plastins/fimbrins are conserved actin-bundling proteins contributing to motility, cytokinesis, and other cellular processes by organizing actin assemblies of strikingly different geometries as in aligned bundles and branched networks. We propose that this unique ability stems from an allosteric communication between the two actin-binding domains (ABD1/2) engaged in a tight spatial association. We found that although ABD1 binds actin first, ABD2 can bind to actin three orders of magnitude stronger if not inhibited by an equally strong allosteric engagement with ABD1. Binding of ABD1 to actin lessened the inhibition, enabling weak bundling within aligned bundles. A mutation mimicking physiologically relevant phosphorylation at the ABD1-ABD2 interface strongly reduced their association, dramatically potentiating actin cross-linking. Cryo-EM reconstruction revealed the ABD1-actin interface and enabled modeling of the plastin bridge to confirm domain separation in parallel bundles. The characteristic domain organization with a strong allosteric inhibition imposed by ABD1 on ABD2 allows plastins to tune cross-linking, contributing to the assembly and remodeling of actin assemblies with different morphological and functional properties defining the unique place of plastins in actin organization.

Determination of Weak Knock Characteristics for Two-Stroke Spark Ignition UAV Engines Based on Mallat Decomposition Algorithm

Two-stroke spark ignition (SI) unmanned aerial vehicle (UAV) engines do not allow heavy knock and require a certain knock safety margin. However, weak knock can help the engine increase power output and reduce fuel consumption. To accurately extract the knock characteristics of engine vibration signals under the condition of weak knock, a signal feature extraction method based on the Mallat decomposition algorithm was proposed. Mallat decomposition algorithm can decompose the signal into two parts: a low-frequency signal and a high-frequency noise signal. The decomposed high-frequency noise is eliminated, and the low-frequency signal is retained as the characteristic domain signal. Simulation results show the effectiveness of the proposed algorithm. The engine vibration signal of a two-stroke SI UAV engine was decomposed into the low-frequency signal and the high-frequency signal by the Mallat decomposition algorithm. The low-frequency signal is taken as the knock characteristic domain signal component, and the wavelet packet energy method is used to verify the correctness of the obtained signal component. The relative energy parameter is calculated by using the knock characteristic domain signal component, which can be used as the determination index of knock intensity. This method provides a reference for the weak knock control of two-stroke SI UAV engines.

Factors Associated with Domestic Violence in Rural Bangladesh

Women’s experience of domestic violence has adverse consequences on women’s health globally and is itself affected by several factors. This study aims to determine the factors that are associated with experience of any form of domestic violence in rural Bangladesh. Data were derived from the baseline survey database of Suchana, a large-scale nutrition program in Bangladesh. Data of 5,440 women from poor households in rural areas were analyzed. Descriptive statistics were used to summarize the data. Multilevel logistic regression analysis was conducted to determine the factors that were significantly associated with experiencing any form of domestic violence. The prevalence of women experiencing domestic violence was found to be 35% and household food insecurity was 86%. Of the women’s characteristic domain, age at marriage, lack of any support from household members, visit from non-governmental organizations (NGO) health professionals, number of children, and decision-making power of women at the household level were significantly associated with reporting of domestic violence. Of the household characteristic domain, the associated factors were having a male household head, increased household size, low socio-economic status, having a loan, experience of at least one crisis event, and household food insecurity. The strength of association between household food insecurity and domestic violence was higher among poor families. Experience of domestic violence is inevitably associated with women’s decision-making power and household food insecurity. Behavioral change communication interventions may help to positively affect decision-making power but a holistic approach needs to be undertaken to reduce food insecurity, for which the underlying mechanism of food insecurity in Bangladesh needs to be explored further.

AFM and NMR imaging of squid tropomyosin Tod p1 subjected to high hydrostatic pressure: evidence for relationships among topography, characteristic domain and allergenicity

The surface topography, characteristic domain and allergenicity of squid tropomyosin Tod p1 (TMTp1) treated under single- and two-cycle high hydrostatic pressure (HHP) were analyzed.

Ferroelectric and Structural Antiphase Domains in Hexagonal RMnO3

ABSTRACTWe have investigated characteristic ferroelectric and structural antiphase domain structures in single crystals of hexagonal RMnO3 (R=Y, Ho, Lu, and Yb) by obtaining various electron diffraction patterns, dark-filed images and high-resolution lattice images. In the ferroelectric phase of RMnO3 characteristic domain structures consisting of six ferroelectric and structural antiphase domains, which can be identified as the “cloverleaf” pattern, is found in the (110) plane, in addition to the (001) plane, and are inherent to the ferroelectric phase of hexagonal RMnO3. In domain configuration with the cloverleaf pattern in the (110) plane, the structural antiphase boundaries are inclined to be parallel to the [001] direction.

Monoclonal antibodies reveal the alteration of the rhodocetin structure upon α2β1 integrin binding

The α2β1 antagonist rhodocetin from Calloselasma rhodostoma is a heterotetrameric CLRP (C-type lectin-related protein) consisting of four distinct chains, α, β, γ and δ. Via their characteristic domain-swapping loops, the individual chains form two subunits, αβ and γδ. To distinguish the four chains which share similar molecular masses and high sequence homologies, we generated 11 mAbs (monoclonal antibodies) with different epitope specificities. Four groups of distinct mAbs were generated: the first targeted the rhodocetin β chain, the second group bound to the αβ subunit mostly in a conformation-dependent manner, the third group recognized the γδ subunit only when separated from the αβ subunit, whereas a fourth group interacted with the γδ subunit both in the heterotetrameric molecule and complexed with the integrin α2 A-domain. Using the specific mAbs, we have shown that the rhodocetin heterotetramer dissociates into the αβ and γδ subunit upon binding to the integrin α2 A-domain at both the molecular and cellular levels. After dissociation, the γδ subunit firmly interacts with the α2β1 integrin, thereby blocking it, whereas the rhodocetin αβ subunit is released from the complex. The small molecular interface between the αβ and γδ subunits within rhodocetin is mostly mediated by charged residues, which causes the two dissociated subunits to have hydrophilic surfaces.

Structural Change during the Formation of Directly Bonded Silicon Substrates

The use of Si(011)/Si(001) direct silicon bonding (DSB) substrates is a key element of future complementary metal-oxide-semiconductor device technology. In the conventional bonding process, it is necessary to remove interfacial SiO2 to achieve direct atomic bonding. In this study, using X-ray microdiffraction and transmission electron microscopy, we investigate the structural changes caused by oxide out-diffusion annealing (ODA). It is revealed that crystallinity of the bonded Si(011) layer is degraded after low temperature ODA and gradually recovered with an increase in the ODA temperature and annealing time, which is well correlated with the interfacial SiO2/Si morphology. Characteristic domain textures depending on the ODA temperature are also detected.