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Background: Magnesium may be an important physiological regulator of myosin motor activity. Results: Mg 2ϩ inhibits the ADP release rate constant in the subset of myosins examined and reduces actin affinity in the post-hydrolysis state in myosin V. Conclusion: Mg 2ϩ alters contractile velocity without altering overall tension-generating capacity. Significance: Mg 2ϩ -dependent regulation of motor activity is conserved in myosin motors.

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The adsorption and assembly of individual and submonolayered TiOPc on Ag(111), Cu(111), and Au(111) have been investigated by scanning tunneling microscopy (STM) and spectroscopy. High resolution STM imaging as well as dI/dV and I−z measurements reveal that TiOPc adsorbed on Ag(111) adopts either O-up or O-down configuration. An intermolecular dipole−dipole interaction leads to the fact that neighboring TiOPc molecules in alternating O-up and O-down configurations form a highly ordered checkerboard assembly structure on Ag(111). However, no large size TiOPc assemblies are observed on Cu(111) and Au(111) due to low surface mobility and diffusivity caused by strong TiOPc−Cu(111) interaction and the templating effect by the reconstructed herringbone structure of Au(111), respectively. Instead, molecular dimers on both Au(111) and Cu(111) as well as molecular aggregates on Au(111) are routinely observed in experiments, indicating that the intermolecular dipole−dipole attraction and weak hydrogen bonding coplay an important role in steering the adsorption and assembly of the TiOPc molecules on the coinage metal surfaces.

Background Despite their widespread distribution and ecological importance, protists remain one of the least understood components of the soil and rhizosphere microbiome. Knowledge of the roles that protists play in stimulating organic matter decomposition and shaping microbiome dynamics continues to grow, but there remains a need to understand the extent to which biological and environmental factors mediate protist community assembly and dynamics. We hypothesize that protists communities are filtered by the influence of plants on their rhizosphere biological and physicochemical environment, resulting in patterns of protist diversity and composition that mirror previously observed diversity and successional dynamics in rhizosphere bacterial communities. Results We analyzed protist communities associated with the rhizosphere and bulk soil of switchgrass (SG) plants (Panicum virgatum) at different phenological stages, grown in two marginal soils as part of a large-scale field experiment. Our results reveal that the diversity of protists is lower in rhizosphere than bulk soils, and that temporal variations depend on soil properties but are less pronounced in rhizosphere soil. Patterns of significantly prevalent protists groups in the rhizosphere suggest that most protists play varied ecological roles across plant growth stages and that some plant pathogenic protists and protists with omnivorous diets reoccur over time in the rhizosphere. We found that protist co-occurrence network dynamics are more complex in the rhizosphere compared to bulk soil. A phylogenetic bin-based null model analysis showed that protists’ community assembly in our study sites is mainly controlled by homogenous selection and dispersal limitation, with stronger selection in rhizosphere than bulk soil as SG grew and senesced. Conclusions We demonstrate that environmental filtering is a dominant determinant of overall protist community properties and that at the rhizosphere level, plant control on the physical and biological environment is a critical driver of protist community composition and dynamics. Since protists are key contributors to plant nutrient availability and bacterial community composition and abundance, mapping and understanding their patterns in rhizosphere soil is foundational to understanding the ecology of the root-microbe-soil system.

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Actin and microtubule cytoskeletons regulate cell morphology, participate in organelle trafficking and function in response to diverse environmental cues. Precise spatial-temporal coordination between these two cytoskeletons is essential for cells to live and move. Here, we report a novel crosstalk between actin and microtubules, in which the branched actin maintains microtubule organization, dynamics and stability by affecting tubulin acetylation levels. We observed that acetylated tubulin significantly decreases upon perturbation of the Arp2/3-branched actin. We subsequently discover that HDAC6 participates in this process by altering its interaction with tubulin and the Arp2/3-stabilizer cortactin. We further identify that the homeostasis of branched actin controls mitochondrial distribution via this microtubule acetylation-dependent mechanism. Our findings shed new light on the integral view of cytoskeletal networks, highlighting post-translational modification as another possible form of cytoskeletal inter-regulation, aside from the established crosstalks through structural connection or upstream signaling pathways.

Many frequent and severe air pollution incidents have emerged across the vast parts of China recently. The identification of factors and mapping social vulnerability has become extremely necessary for environmental management and sustainable development. However, studies associating social vulnerability with air pollution remain sparse. With reference to research achievements of social vulnerability, this study made a new trial regarding social vulnerability assessment to air pollution. With the projection pursuit cluster (PPC) model, the top three factors contributing to social vulnerability index (SVI) were discovered and SVI and SVI dimensions (susceptibility, exposure, and adaptability) were evaluated. Results revealed that adaptability values are higher than susceptibility and exposure values. SVI is in a poor condition as, for the whole region, most values belong to the high-medium level. High SVI values mainly appear in the northern and the southern ends of study area. SVI in Shanghai is lower than in Jiangsu and Zhejiang provinces. On the scale of prefecture-level city, it can be found that the low-value centers of SVI always occurred in urban core areas. The spatial variation and inequality in social vulnerability provide policy-makers a scientific basis for air pollution prevention and sustainable management.