ToxR Is Required for Biofilm Formation and Motility of Vibrio Parahaemolyticus

Vibrio parahaemolyticus, the leading cause of seafood-borne gastroenteritis, has the ability to form biofilms on biotic and abiotic surfaces. Biofilm formation is a complicated process involving many specific structures and regulatory processes. The most significant of the structures and processes include polar and lateral flagella, mannose-sensitive hemagglutinin typeⅣpili, chitin-regulated pili,capsular polysaccharide (CPS), exopolysaccharide

LRP6 in mesenchymal stem cells is required for bone formation during bone growth and bone remodeling

Lipoprotein receptor-related protein 6 （LRP6） plays a critical role in skeletal development and homeostasis in adults. However, the role of LRP6 in mesenchymal stem cells （MSCs）, skeletal stem cells that give rise to osteoblastic lineage, is unknown. In this study, we generated mice lacking LRP6 expression specifically in nestin＋ MSCs by crossing nestin-Cre mice with LRP6 flox mice and investigated the functional changes of bone marrow MSCs and skeletal alterations. Mice with LRP6 deletion in nestin＋ cells demonstrated reductions in body weight and body length at I and 3 months of age. Bone architecture measured by microCT （uCT） showed a significant reduction in bone mass in both trabecular and cortical bone of homozygous and heterozygous LRP6 mutant mice. A dramatic reduction in the numbers of osteoblasts but much less significant reduction in the numbers of osteoclasts was observed in the mutant mice. Osterix＋ osteoprogenitors and osteocalcin＋ osteoblasts significantly reduced at the secondary spongiosa area, but only moderately decreased at the primary spongiosa area in mutant mice. Bone marrow MSCs from the mutant mice showed decreased colony forming, cell viability and cell proliferation. Thus, LRP6 in bone marrow MSCs is essential for their survival and proliferation, and therefore, is a key positive regulator for bone formation during skeletal growth and remodeling.

Arabidopsis thaliana NOP10 is required for gametophyte formation

The female gametophyte is crucial for sexual reproduction of higher plants, yet little is known about the molecular mechanisms underlying its development. Here, we report that Arabidopsis thaliana NOP10 （AtNOP10） is required for female gametophyte formation. AtNOP10 was expressed predominantly in the seedling and reproductive tissues, including anthers, pollen grains, and ovules. Mutations in AtNOP10 interrupted mitosis of the functional megaspore during early development and prevented polar nuclear fusion in the embryo sacs. AtNOP10 shares a high level of amino acid sequence similarity with Saccharornycescerevisiae （yeast） NOPIo （ScNOP1o）, an important compo- nent of the H/ACA small nucleolar ribonucleoprotein particles （H/ACA snoRNPs） implicated in 18S rRNA synthe- sis and rRNA pseudouridylation. Heterologous expression of ScNOP10 complemented the mutant phenotype of Atnop10. Thus, AtNOPIo influences functional megaspore mitosis and polar nuclear fusion during gametophyte formation in Arabidopsis.