Project description:How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we find that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (KYA), and after no more than 8,000-year isolation period in Beringia. Native Americans diversified into two basal genetic branches around 13 KYA, one in North and South America and the other restricted to North America. Subsequent gene flow resulted in some Native Americans sharing ancestry with present-day East Asians and Australo-Melanesians, the latter possibly through the ancestors of Aleutian Islanders. Putative relict populations in South America, including the historical Pericúes and Fuego-Patagonians, are not directly related to modern Australo-Melanesians.
Project description:In the present study, endogenous cysteine S-nitrosation site and S-nitrosated proteins were identified by iodo-TMT labeling during somatic embryogenesis in Brazilian pine, an endangered native conifer of South America.
Project description:Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing unprecedented changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in the Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen) and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies), Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific. The study was carried out at the Brazilian Antarctic Station Comandante Ferraz (EACF, 62M-BM-004M-bM-^@M-^YS, 58M-BM-021M-bM-^@M-^YW), located in Martel Inlet, Admiralty Bay, King George Island, Antarctic Peninsula, which is part of the South Shetlands Archipelago in Maritime Antarctica. It is a medium sized research station with a population of 10 to 15 people during the winter months (March to November) and about 60 people during the austral summer months (November to March). During the austral summers of 2006 M-bM-^@M-^S 2007 and 2008 M-bM-^@M-^S 2009, the vascular plants D. antarctica or C. quitensis were sampled, where both plants were found, in triplicate at six different sites: A M-bM-^@M-^S Arctowski (2006 M-bM-^@M-^S 2007), Q M-bM-^@M-^S Quimica (2006 M-bM-^@M-^S 2007), I M-bM-^@M-^S Ipanema (2006 M-bM-^@M-^S 2007), M M-bM-^@M-^S North Mountain (2008 M-bM-^@M-^S 2009), D M-bM-^@M-^S Demay Point (2008 M-bM-^@M-^S 2009), C M-bM-^@M-^S Copacabana (2008 M-bM-^@M-^S 2009) (Figure 1). Points A, C and D were located inside an environmental protected area. Point A is close to the Arctowski Polish Station and next to a colony of Adelie penguins (Pygoscelis adeliae), point C is next to the USA summer station Copacabana in a Gentoo penguin (P. papua) colony, and point D is near to a Polish refuge next to a colony of Chinstrap penguins (P. antarcticus). At point I, there were no penguin colonies present, but this section was used as a nesting site by local species of flying birds. Point Q was located in the vicinity of the EACF; thus there has been (and continues to be) an intense anthropogenic influence on this spot, which is not the case at the other sampling sites. Point M was located at the top of North Mountain, around 200 m altitude. This site has no influence from penguin colonies and only a few nests of skua (Catharacta sp.) were observed. At each sampling site, triplicate soil samples were taken for chemical and biological analyses, with the exception of the Arctowski site (A) where we only took two replicates. Each vascular plant sample was frozen (-20M-BM-0C) at the EACF.
Project description:Deep seas marine fungus SST2-VLC fractions. Isolated from soil sediment from South Shetland Trench, Antarctica (-58.90865, -61.122976, ~5100 m). Large scale fermentation on rice medium followed by subsequent methanol extraction. Finally, vacuum liquid chromatography was completed using an increasing gradient from hexane-dichloromethane-methanol.
Project description:Investigation of whole genome gene expression level in Pseudozyma antarctica T-34, compared to Ustilago maydis UM521. To clarify the transcriptomic characteristics of Pseudozyma antarctica under the conditions of high MEL production, a DNA microarray of both the strains, Pseudozyma antarctica T-34 and Ustilago maydis UM521 was prepared and analyzed the transcriptomes.