A genetic screen to uncover mechanisms underlying lipid transfer protein function at membrane contact sites.

Lipid transfer proteins mediate the transfer of lipids between organelle membranes, and the loss of function of these proteins has been linked to neurodegeneration. However, the mechanism by which loss of lipid transfer activity leads to neurodegeneration is not understood. In Drosophila photoreceptors, depletion of retinal degeneration B (RDGB), a phosphatidylinositol transfer protein, leads to defective phototransduction and retinal degeneration, but the mechanism by which loss of this activity leads to retinal degeneration is not understood. RDGB is localized to membrane contact sites through the interaction of its FFAT motif with the ER integral protein VAP. To identify regulators of RDGB function in vivo, we depleted more than 300 VAP-interacting proteins and identified a set of 52 suppressors of rdgB The molecular identity of these suppressors indicates a role of novel lipids in regulating RDGB function and of transcriptional and ubiquitination processes in mediating retinal degeneration in rdgB9 The human homologs of several of these molecules have been implicated in neurodevelopmental diseases underscoring the importance of VAP-mediated processes in these disorders.

Comparative evaluation of the pushout bond strength of two root-end materials: An in vitro study.

AIM: The aim of this study is to evaluate the pushout bond strength of two bioceramic materials, two component calcium trisilicate material (biodentine), and premixed calcium trisilicate putty (Endosequence root repair material-fast set putty). SUBJECTS AND METHODS: 20 maxillary incisors were used in the study. Apical sections of 3mm were obtained and retro cavities to a depth of 3mm were prepared using a straight fissure bur. Another transverse section was made 4-mm coronal to the previous section. The specimens were placed into acrylic resin rings and separated into two groups and their cavities filled with the materials. The pushout test was carried out using a universal testing machine at a cross head speed of 0.5 mm/min, and the specimens were examined in a stereomicroscope at to evaluate the modes of failure. STATISTICAL ANALYSIS: The pushout bond strength values were analyzed using the unpaired t-test, and the modes of failure were compared using Fisher's exact test. RESULTS: The pushout bond strength was seen to be significantly higher (P < 0.001) for the two-component calcium trisilicate material (11.596 ± 3.309). Cohesive failure patterns were observed in both the test groups. CONCLUSION: Two component calcium trisilicate material demonstrated higher bond strength values to apical dentine.