Ancient DNA from coral-hosted Symbiodinium reveal a static mutualism over the last 172 years.

Ancient DNA (aDNA) provides powerful evidence for detecting the genetic basis for adaptation to environmental change in many taxa. Among the greatest of changes in our biosphere within the last century is rapid anthropogenic ocean warming. This phenomenon threatens corals with extinction, evidenced by the increasing observation of widespread mortality following mass bleaching events. There is some evidence and conjecture that coral-dinoflagellate symbioses change partnerships in response to changing external conditions over ecological and evolutionary timescales. Until now, we have been unable to ascertain the genetic identity of Symbiodinium hosted by corals prior to the rapid global change of the last century. Here, we show that Symbiodinium cells recovered from dry, century old specimens of 6 host species of octocorals contain sufficient DNA for amplification of the ITS2 subregion of the nuclear ribosomal DNA, commonly used for genotyping within this genus. Through comparisons with modern specimens sampled from similar locales we show that symbiotic associations among several species have been static over the last century, thereby suggesting that adaptive shifts to novel symbiont types is not common among these gorgonians, and perhaps, symbiotic corals in general

Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria.

Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen-protium and deuterium-that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ(2)H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ(2)H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ(2)H suggest much potential as an environmental recorder of metabolism

Isotopic and genetic methods reveal the role of the gut microbiome in mammalian host essential amino acid metabolism.

Intestinal microbiota perform many functions for their host, but among the most important is their role in metabolism, especially the conversion of recalcitrant biomass that the host is unable to digest into bioavailable compounds. Most studies have focused on the assistance gut microbiota provide in the metabolism of carbohydrates, however, their role in host amino acid metabolism is poorly understood. We conducted an experiment on Mus musculus using 16S rRNA gene sequencing and carbon isotope analysis of essential amino acids (AAESS) to quantify the community composition of gut microbiota and the contribution of carbohydrate carbon used by the gut microbiome to synthesize AAESS that are assimilated by mice to build skeletal muscle tissue. The relative abundances of Firmicutes and Bacteroidetes inversely varied as a function of dietary macromolecular content, with Firmicutes dominating when mice were fed low-protein diets that contained the highest proportions of simple carbohydrates (sucrose). Mixing models estimated that the microbial contribution of AAESS to mouse muscle varied from less than 5% (threonine, lysine, and phenylalanine) to approximately 60% (valine) across diet treatments, with the Firmicute-dominated microbiome associated with the greatest contribution. Our results show that intestinal microbes can provide a significant source of the AAESS their host uses to synthesize structural tissues. The role that gut microbiota play in the amino acid metabolism of animals that consume protein-deficient diets is likely a significant but under-recognized aspect of foraging ecology and physiology

Temporal and population trends in human exploited pinnipeds from Tierra del Fuego

Archaeological sites on the coast of Tierra del Fuego, Argentina, provide a biogeochemical record that can inform us about those ecological dynamics. An abundance of southern fur seal (Arctocephalus australis) and southern sea lion (Otaria flavescens) remains provide a valuable resource to reconstruct ancient and modern food webs. To quantify ecological relationships, we measured bulk stable isotope ratios from bone collagen in otariids and other associated animals, several of which are potential otariid prey. Variations in bulk stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) are linked to potential dietary differences and habitat specialization between coastal areas or the open ocean in populations ranging in age from 7000 cal. Years BP to modern. We observed increases in the variability of these isotopic compositions over time, which suggests a diversity in the diets and habitats of otariids. Shifts in marine food webs occurred during the transition from subsistence hunting of otariids to industrial hunting and expanded human influence. We conclude that direct human influences, such as hunting and habitat alteration, were the major drivers of ecological change in southern South American marine ecosystems.Fil: Nye, Jonathan W.. University of California; Estados UnidosFil: Zangrando, Atilio Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martinoli, Maria Paz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fogel, Marilyn. University of California; Estados Unido

Characterization of pysio-chemical properties of novel one stop chemical method in preparations of copper nanofluids and possible explanations

Nanofluid is a dilute suspension containing particles in nanometer sized which are dispersed in the base fluid like ethylene glycol or water. Nanofluid is one of the crucial discovery in modern science which found to be having better thermal properties compared with conventional fluids like water or ethylene glycol thus makes it ideal to be applied and utilized in many areas in heat transfer area such as cooling, utilized as fluid for heat echangers and etc. Besides, the nanofluid with the improved thermal properties could solve the problem faced by various industries in the area of heat transfer. For example, in the semiconductor industry, the needs of superior cooling coolant are very crucialJn this paper, presents about preparation of copper nanofluid using novel one stop chemical method by reducing copper sulphate pentahydrate using reduction agent which is sodium hypophosphite in ethylene glycol as base fluids. The obtained nanofluid by using this novel one stop method is more stable besides cheaper and faster compared with two stop method whereby in the two step method, the production of the nanoparticles and the nanofluids are isolated. The process of drying, storage and transportation of the nanoparticles that takes place in two step method have cause the agglomeration and sedimentation of the nanofluids. As the result, the agglomeration could cause the settlement and clogging in the microchannel besides reduce the thermal conductivity. Therefore in the novel one stop method the production of the nanoparticles and the nanofluids are combined and not separated to avoid the process of drying, storage and transportation of nanoparticles. Meanwhile the nanofluid that obtained were analyzed using Transmission Electron Microscopy (TEM), UV-Vis Spectrophotometer, Viscometer and Fourier Transform Infared Spectroscopy (FTIR). The effect and influences of pH and dilution to the reaction rate and properties of nanofluid were also investigated

Cumulative Human Impacts on Pinnipeds Over the Last 7,500 Years in Southern South America

Our research program on this topic combines zooarchaeological and stable isotope studies from a historical ecology perspective. We originated this approach, and developed new analytical techniques, to better link archaeological evidence with paleo-ecosystem reconstructions (Zangrando, Panarello et al. 2014). In order to assess the relationship between pinnipeds and hunter-gatherers in Tierra del Fuego, we developed zooarchaeological analyses based on predictions from foraging models. Since information about past abundance or distribution of prey is rare in the southern South Atlantic, zooarchaeological evaluations were basedmainly on modern ecological parameters. Current foraging ecology of pinnipeds may be a useful framework for understanding archaeological evidence; however, that framework might present an incomplete picture of the actual range ofbehaviors and ecological roles that these resources could have provided for human populations in the past. In fact, the historical distribution of pinnipeds in Patagonia and Tierra del Fuego is poorly understood. Moreover, species distributions are likely to have fluctuated throughout time because of different environmental factors, or as a by-product of cumulative human impacts on marine ecosystems. Thus, the range of variation reflected in our knowledge about current pinniped distribution may not sufficiently represent the past.Against this context, an isotopic zooarchaeological approach provides a convenient route to expand our knowledge about human-pinniped relations at long-time scales (Zangrando,Panarello et al. 2014).Fil: Nye, Jonathan W.. University of California; Estados UnidosFil: Zangrando, Atilio Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martinoli, Maria Paz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vázquez, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fogel, Marilyn. University of California; Estados Unido

Dynamics of atmospheric combined inorganic nitrogen utilization in the coastal waters off North Carolina

Phytoplankton in nitrogen-depleted coastal Atlantic waters off North Carolina, USA, had a positive response to nitrogen added as rain (DIN: NO3- and NH4+) or directly as NO3- or NH4+. Increases in primary production, photopigments, and cellular protein concentrations were observed when nitrogen Limitation was alleviated. NO3- concentrations decreased faster than those of NH4+ in 670 l mesocosm experiments, performed in October 1993 and March and April 1994. Stable nitrogen isotope measurements (delta(15)N) Of particulate N typically showed similar responses to the nitrogen additions. The delta(15)N decreased as the different DIN sources, having delta(15)N values near 0 parts per thousand, were incorporated into cell biomass. The smallest changes (about 1 parts per thousand) occurred in the Delta(15)N (delta(15)N(initial) - delta(15)N(final)) from nitrate additions. A greater shift of about 2 parts per thousand was observed with added DIN from rain, even though delta(15)N Of total DIN was similar. Ammonium additions resulted in the largest difference from the control, about 6 to 7 parts per thousand. This fractionation is indicative of isotopic fractionation during enzymatic incorporation and active transport of ammonium into the cells. In parallel incubations, C-14-bicarbonate was added along with rain in addition to all N additions and controls. Subcellular C-14-labeled fractions from these samples showed a short-term response to nitrogen additions and included an increase in the low molecular weight fraction after the first light incubation (from dawn to dusk). Carbon was allocated into protein after a 24 h period that encompassed the night incubation