DDX5 plays essential transcriptional and post-transcriptional roles in the maintenance and function of spermatogonia

Mammalian spermatogenesis is sustained by mitotic germ cells with self-renewal potential known as undifferentiated spermatogonia. Maintenance of undifferentiated spermatogonia and spermatogenesis is dependent on tightly co-ordinated transcriptional and post-transcriptional mechanisms. The RNA helicase DDX5 is expressed by spermatogonia but roles in spermatogenesis are unexplored. Using an inducible knockout mouse model, we characterise an essential role for DDX5 in spermatogonial maintenance and show that Ddx5 is indispensable for male fertility. We demonstrate that DDX5 regulates appropriate splicing of key genes necessary for spermatogenesis. Moreover, DDX5 regulates expression of cell cycle genes in undifferentiated spermatogonia post-transcriptionally and is required for cell proliferation and survival. DDX5 can also act as a transcriptional co-activator and we demonstrate that DDX5 interacts with PLZF, a transcription factor required for germline maintenance, to co-regulate select target genes. Combined, our data reveal a critical multifunctional role for DDX5 in regulating gene expression programmes and activity of undifferentiated spermatogonia

An Investigation Into the Use of Groundnut as Fine Aggregate Replacement

The suitability of groundnut shell as a constituent material in concrete was investigated by re- placing proportions by volume of ne aggregate (river sand) with groundnut shells. Physical properties of cement, groundnut shells and aggregates were determined. Concrete cubes measur- ing 150x150x150mm were cast. Groundnut shells were used to replace ne aggregate at 0, 5, 15, 25, 50 and 75% replacement levels. The e ects of the groundnut shells on the workability of fresh concrete were determined by the slump and compacting factor value tests. Compressive strengths and density values of the concrete cubes were evaluated at 28 days at di erent percentage replacement levels obtaining a range of values of 34.37, 40.59, 21.33, 17.78, 12.44, 7.56N/mm2 and 2402.96, 2533.33, 2349.62, 2215.30, 2121.48, and 1854.81Kg/m3 respectively. Increase in percentage of groundnut shells in the cubes led to a corresponding reduction in densities of the cubes and compressive strength values. At a replacement value of 25% and above, of ne aggregate with groundnut shells; lightweight concrete was produced which could be used where low stress is required. Hence groundnut shells can be used for the production of lightweight concrete.Keywords: groundnut shell, lightweight, aggregates, concrete, compressive strengt

Formation of ring-shaped microtubule assemblies through active self-organization on dynein

Microtubule (MT)-kinesin, a biomolecular motor system, is a promising candidate for construction of artificial biomachines for a variety of nanotechnology applications. An active self-organization (AcSO) method involving a specific streptavidin (St)-biotin (Bt) interaction has been developed to assemble MTs into a highly ordered structure by exploiting their motility on a kinesincoated surface. Dynein is another biomolecular motor that moves along the MTs in the opposite direction from kinesin. Dynein has not yet been used to demonstrate the AcSO of MTs. In this study, we report the first successful demonstration of the AcSO of MTs on a dynein-coated surface to produce ring-shaped MT assemblies similar to those of kinesin. We found that ring-shaped MT assemblies obtained on dynein showed equal clockwise and counterclockwise rotational motion. This work will enrich the building blocks for designing future oriented motor protein-based artificial devices