Genetic variation and population structure in native Americans

We examined genetic diversity and population structure in the American landmass using 678 autosomal microsatellite markers genotyped in 422 individuals representing 24 Native American populations sampled from North, Central, and South America. These data were analyzed jointly with similar data available in 54 other indigenous populations worldwide, including an additional five Native American groups. The Native American populations have lower genetic diversity and greater differentiation than populations from other continental regions. We observe gradients both of decreasing genetic diversity as a function of geographic distance from the Bering Strait and of decreasing genetic similarity to Siberians--signals of the southward dispersal of human populations from the northwestern tip of the Americas. We also observe evidence of: (1) a higher level of diversity and lower level of population structure in western South America compared to eastern South America, (2) a relative lack of differentiation between Mesoamerican and Andean populations, (3) a scenario in which coastal routes were easier for migrating peoples to traverse in comparison with inland routes, and (4) a partial agreement on a local scale between genetic similarity and the linguistic classification of populations. These findings offer new insights into the process of population dispersal and differentiation during the peopling of the Americas.     

Cadmium bioaccumulation in Lamellidens marginalis and human health risk assessment: A case study in India

Abstract

Lamellidens marginalis is an easily available food with high nutritive value. The present study is based on the East Kolkata Wetlands (EKW), India that produces mussels, consumed by human. Thus, the study of heavy metal pollution in the wastewater and mussel, and its transport to human is considered to be need of the hour to assess the health risk to human. The present study focuses on the cadmium accumulation in the outer exposed organs and the internal organs of L. marginalis. The mussel, sediment, and water were collected from the field and analyzed in the laboratory. The environmental factors were analyzed in situ. The survey work was conducted among the consumers of mussel around the EKW to predict the effect of cadmium on human. The result showed that the cadmium concentration of water was relatively important for the bioaccumulation process in L. marginalis. People having low level of income and age above forty, living adjoining the EKW were at high risk of cadmium pollution. The hazard quotient value of the above group was highest among all the groups across age and income. A ‘biofilter’ technique was suggested to mitigate the biomagnification of cadmium at the EKW.     

Complete Genome Sequence of Newcastle Disease Virus Mesogenic Vaccine Strain R2B from India

Mesogenic vaccine strains of Newcastle disease virus (NDV) are widely used in many countries of Asia and Africa to control the Newcastle disease of poultry. In India, the mesogenic strain R2B was introduced in 1945; it protects adult chickens that have been preimmunized with a lentogenic vaccine virus and provides long-lasting immunity. In this article, we report the complete genome sequence of the hitherto unsequenced Indian vaccine virus strain R2B. The viral genome is 15,186 nucleotides in length and contains the polybasic amino acid motif in the fusion protein cleavage site, indicating that this vaccine strain has evolved from a virulent virus. Phylogenetic analysis of this mesogenic vaccine virus classified it with the viruses belonging to genotype III of the class cluster II of NDV.     

Macromolecular and small-molecule modulation of intracellular Aβ42 aggregation and associated toxicity

Aβ (amyloid β-peptide) has a central role in AD (Alzheimer's disease) where neuronal toxicity is linked to its extracellular and intracellular accumulation as oligomeric species. Searching for molecules that attenuate Aβ aggregation could uncover novel therapies for AD, but most studies in mammalian cells have inferred aggregation indirectly by assessing levels of secreted Aβ peptide. In the present study we establish a mammalian cell system for the direct visualization of Aβ formation by expression of an Aβ(42)-EGFP (enhanced green fluorescent protein) fusion protein in the human embryonic kidney cell line T-REx293, and use this to identify both macromolecules and small molecules that reduce aggregation and associated cell toxicity. Thus a molecular shield protein AavLEA1 [Aphelenchus avenae LEA (late embryogenesis abundant) protein 1], which limits aggregation of proteins with expanded poly(Q) repeats, is also effective against Aβ(42)-EGFP when co-expressed in T-REx293 cells. A screen of polysaccharide and small organic molecules from medicinal plants and fungi reveals one candidate in each category, PS5 (polysaccharide 5) and ganoderic acid DM respectively, with activity against Aβ. Both PS5 and ganoderic acid DM probably promote Aβ aggregate clearance indirectly through the proteasome. The model is therefore of value to study the effects of intracellular Aβ on cell physiology and to identify reagents that counteract those effects.