Mutation of the Zebrafish Nucleoporin elys Sensitizes Tissue Progenitors to Replication Stress

The recessive lethal mutation flotte lotte (flo) disrupts development of the zebrafish digestive system and other tissues. We show that flo encodes the ortholog of Mel-28/Elys, a highly conserved gene that has been shown to be required for nuclear integrity in worms and nuclear pore complex (NPC) assembly in amphibian and mammalian cells. Maternal elys expression sustains zebrafish flo mutants to larval stages when cells in proliferative tissues that lack nuclear pores undergo cell cycle arrest and apoptosis. p53 mutation rescues apoptosis in the flo retina and optic tectum, but not in the intestine, where the checkpoint kinase Chk2 is activated. Chk2 inhibition and replication stress induced by DNA synthesis inhibitors were lethal to flo larvae. By contrast, flo mutants were not sensitized to agents that cause DNA double strand breaks, thus showing that loss of Elys disrupts responses to selected replication inhibitors. Elys binds Mcm2-7 complexes derived from Xenopus egg extracts. Mutation of elys reduced chromatin binding of Mcm2, but not binding of Mcm3 or Mcm4 in the flo intestine. These in vivo data indicate a role for Elys in Mcm2-chromatin interactions. Furthermore, they support a recently proposed model in which replication origins licensed by excess Mcm2-7 are required for the survival of human cells exposed to replication stress

POPULATION DYNAMICS OF MOSQUITOES IN COIMBATORE CITY, TAMIL NADU, INDIA

Mosquitoes are causative agents for many diseases and affect millions of people worldwide. A detailed investigation was undertaken to study the mosquito population dynamics in selected areas of Coimbatore city, namely, Puliyakulam, Karamadai and Sennanur, from November 2018-May 2019. The adult mosquitoes were collected by using a Biogent mosquitaire trap. During the study time, weather parameters were reported in order to determine these factors which influence the mosquito population. Canonical Correspondence Analysis (CCA) was employed to study the pattern of variation in mosquito species. A total number of 3297 adult mosquitoes were collected that belonged to four genera and nine species. The most abundant species was found to be Culex quinquefasciatus, followed by Aedes aegypti and Armigers subalbatus. CCA showed a positive relationship in Aedes aegypti with rainfall. The study provides essential information on population dynamics and various vector species of mosquitoes in selected areas of Coimbatore city. &nbsp

Fibronectin in periodontal health and disease

Fibronectin is a main component of connective tissue and has various biologically significant roles to play in tissue integrity, remodelling and repair, apart from influencing pathological processes. This review looks into the physiology of fibronectin and its influences in health and disease

Synthesis of Silver-Doped Zinc Oxide Nanocomposite by Pulse Mode Ultrasonication and Its Characterization Studies

The synthesis of silver-doped zinc oxide (Ag:ZnO) nanocomposite material was achieved using a simple chemical coprecipitation method, in which 0.2 M zinc chloride and 0.001 M silver nitrate coprecipitated with 25% ammonia solution by pulse mode dispersion using ultrasonicator. The obtained silvery white precipitate was dried overnight at 110°C in hot air oven, and the powder was collected. The resulted Ag:ZnO nanocomposite was structurally and optically characterized using various techniques. The X-ray diffraction (XRD) pattern clearly showed the presence of crystalline Ag:ZnO particles. Further, UV-Vis spectrophotometer and fourier transform infrared spectroscopy (FT-IR) results showed the presence of Ag:ZnO nanocomposite at specific wavelengths. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirm that the synthesized Ag:ZnO nanocomposite material was truncated nanorod in shape and has 48 to 226 nm size in diameter