A Myo6 Mutation Destroys Coordination between the Myosin Heads, Revealing New Functions of Myosin VI in the Stereocilia of Mammalian Inner Ear Hair Cells

Myosin VI, found in organisms from Caenorhabditis elegans to humans, is essential for auditory and vestibular function in mammals, since genetic mutations lead to hearing impairment and vestibular dysfunction in both humans and mice. Here, we show that a missense mutation in this molecular motor in an ENU-generated mouse model, Tailchaser, disrupts myosin VI function. Structural changes in the Tailchaser hair bundles include mislocalization of the kinocilia and branching of stereocilia. Transfection of GFP-labeled myosin VI into epithelial cells and delivery of endocytic vesicles to the early endosome revealed that the mutant phenotype displays disrupted motor function. The actin-activated ATPase rates measured for the D179Y mutation are decreased, and indicate loss of coordination of the myosin VI heads or ‘gating’ in the dimer form. Proper coordination is required for walking processively along, or anchoring to, actin filaments, and is apparently destroyed by the proximity of the mutation to the nucleotide-binding pocket. This loss of myosin VI function may not allow myosin VI to transport its cargoes appropriately at the base and within the stereocilia, or to anchor the membrane of stereocilia to actin filaments via its cargos, both of which lead to structural changes in the stereocilia of myosin VI–impaired hair cells, and ultimately leading to deafness

Responsiveness of buckwheat varieties to foliar applications by microfertilizer under forest steppe of the volga region

The yields of modern intensive varieties of buckwheat in arid regions are highly susceptible to adverse hydrothermal growing conditions. The selection of optimal compositions and technologies for using modern agrochemicals that provide an adaptogenic effect and a favourable vegetation regime of plants can be an effective way to stabilize the grain production of this warm-loving but the drought-resistant crop. Scientists have poorly studied these issues and the issues of efficient use of mineral nutrition resources in buckwheat. They studied the responsiveness of buckwheat varieties, that differ in the morphological and biological characteristics of plants, to the foliar application by Yara concentrated complex water-soluble fertilizers containing macroand microelements.The data obtained indicate the presence of varietal specificity, which manifests itself to varying degrees of plant responsiveness to foliar application in the formation of leaf area, grain yield and quality indicators of the crop. The authors made conclusions about the preferred dates for foliar application with the studied Yara complex micronutrient fertilizers. When the foliar application of microelements in the phase of the beginning of grain formation, the K-850 cultivar had the highest yield and the best quality parameters of grains. For the K-899 cultivar, the application in the russeting phase was most effective for grains and affected the best plumpness of the grains. The more powerful morphological potential of Batyr plants was not realized by an adequate increase in yield for the performed feeding. The authors observed a slight tendency to decrease the crude protein content in grains during the foliar application which is probably due to the inverse correlation of this trait with the formation rate of the organic mass of plants