Microbial responses to changes in land use

Background/Question/Methods
Land use change is one of the greatest threats to biodiversity worldwide. This is especially true for land use change that results in the destruction of intact forest, or "deforestation”. Deforestation is causing a loss of biological diversity on an unprecedented scale, especially in the Tropics. It is unclear how the majority of the biodiversity on Earth – microbial biodiversity – is responding to these extraordinary rates of deforestation. I will provide an overview of our current understanding of microbial responses to deforestation. I will focus, as an example, on our current research regarding the effects of deforestation on the diversity of arbuscular mycorrhizal fungi (AMF), bacteria and archaea within Amazon Rainforest soils. This study takes advantage of an established chronosequence of primary rainforest, pastures of various ages, and secondary rainforest to determine the effect of deforestation on the taxonomic, phylogenetic and functional diversity of soil microorganisms, assayed using culture-independent methods.

Results/Conclusions
There is increasing evidence that deforestation significantly affects microbial diversity, and that “recovery” of microbial diversity in secondary forest soils is incomplete. For example, rarefaction curves suggest that the accumulation of AMF taxa is higher for Amazon primary forest soil relative to secondary forest soil. In addition, the community composition varies with land use; three AMF taxa were shared between primary and secondary forests, seven were found only in primary forest, and three were found exclusively in secondary forest soil. We also observed that the phylogenetic diversity of AMF is more reduced in secondary forest soils than expected given the regional pool of AMF taxa.

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High Prevalence of Gammaproteobacteria in the Sediments of Admiralty Bay and North Bransfield Basin, Northwestern Antarctic Peninsula

Microorganisms dominate most Antarctic marine ecosystems, in terms of biomass and taxonomic diversity, and play crucial role in ecosystem functioning due to their high metabolic plasticity. Admiralty Bay is the largest bay on King George Island (South Shetland Islands, Antarctic Peninsula) and a combination of hydro-oceanographic characteristics (bathymetry, sea ice and glacier melting, seasonal entrance of water masses, turbidity, vertical fluxes) create conditions favoring organic carbon deposition on the seafloor and microbial activities. We sampled surface sediments from 15 sites across Admiralty Bay (100502 m total depth) and the adjacent North Bransfield Basin (6931147 m), and used the amplicon 454-sequencing of 16S rRNA gene tags to compare the bacterial composition, diversity, and microbial community structure across environmental parameters (sediment grain size, pigments and organic nutrients) between the two areas. Marine sediments had a high abundance of heterotrophic Gammaproteobacteria (92.4% and 83.8% inside and outside the bay, respectively), followed by Alphaproteobacteria (2.5 and 5.5%), Firmicutes (1.5 and 1.6%), Bacteroidetes (1.1 and 1.7%), Deltaproteobacteria (0.8 and 2.5%) and Actinobacteria (0.7 and 1.3%). Differences in alpha-diversity and bacterial community structure were found between the two areas, reflecting the physical and chemical differences in the sediments, and the organic matter input.Brazilian National Council for Scientific and Technological Development - CNPq (MABIREH/IPY/CAML)CAPES-Master's fellowshipUniv Sao Paulo, Inst Oceanog, Dept Oceanog Biol, Sao Paulo, BrazilUniv Fed Santa Catarina, Ctr Ciencias Biol, Florianopolis, SC, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Ambientais, Diadema, BrazilUniv Fed Rio de Janeiro, Inst Biol, Dept Zool, Rio De Janeiro, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Ambientais, Diadema, BrazilCNPq (MABIREH/IPY/CAML): 520293/2006-1Web of Scienc

Cavity QED and quantum information processing with "hot" trapped atoms

We propose a method to implement cavity QED and quantum information processing in high-Q cavities with a single trapped but non-localized atom. The system is beyond the Lamb-Dick limit due to the atomic thermal motion. Our method is based on adiabatic passages, which make the relevant dynamics insensitive to the randomness of the atom position with an appropriate interaction configuration. The validity of this method is demonstrated from both approximate analytical calculations and exact numerical simulations. We also discuss various applications of this method based on the current experimental technology.Comment: 14 pages, 8 figures, Revte

Medición de impactos en una terraza verde para la definición de estandares de eficiencia en sistemas de techos verdes intensivos y extensivos en condiciones urbanas. Caso de estudio: Ciudad de Córdoba

Una alternativa para moderar el equilibrio en los ecosistemas urbanos e integrar la vegetación a las ciudades, lo constituyen los techos verdes. Dichos sistemas aportan servicios ecosistemicos, como la mitigación de las variaciones de temperatura entre el exterior y el interior de las unidades habitacionales, contribuyendo a la eficiencia energética de las construcciones edilicias. En el presente proyecto de investigación se evalúa la adecuación de esta tecnología a condiciones constructivas reales; como así también el impacto de los dos tipos de sistemas: el extensivo y el intensivo, comparándolos con un techo blanco como testigo. En dos aulas taller contiguas de la facultad de arquitectura se instaló un sistema extensivo de techos verdes (80 m2) y la otra se pintó la loza de blanco (testigo). En el techo del aula testigo se instalaron 3 cubos de simulación de 1 m3 para simular ambos sistemas (extensivo e intensivo) y comparar con el testigo. Se colocaron sensores exteriores, de loza e interiores tanto en ambas aulas como en los cubos, para evaluar la eficiencia energética y en los cubos además, la escorrentía. Se están procesando y analizando los datos recibidos para estimar las propiedades térmicas, las diferencias de temperaturas en los diferentes espacios, así como el impacto energéticode ambos sistemas. Al mismo tiempo se está analizando la detección y detención de la escorrentía de las lluvias recibidas en ese período. Este proyecto permite medir el impacto positivo del techo verde, establecer comparaciones entre sistemas constructivos, y dimensionar la magnitud de algunos de los servicos ecosistémicos que este mismo presta (e.g. regulación térmica, colecta del agua de lluvia, retención y detención de escorrentía, entre otros). La estimación certera de estos beneficios potenciales permitirá la definición de estándares de eficiencia

Fragment C of Tetanus Toxin : New Insights into Its Neuronal Signaling Pathway

When Clostridium tetani was discovered and identified as a Gram-positive anaerobic bacterium of the genus Clostridium, the possibility of turning its toxin into a valuable biological carrier to ameliorate neurodegenerative processes was inconceivable. However, the non-toxic carboxy-terminal fragment of the tetanus toxin heavy chain (fragment C) can be retrogradely transported to the central nervous system; therefore, fragment C has been used as a valuable biological carrier of neurotrophic factors to ameliorate neurodegenerative processes. More recently, the neuroprotective properties of fragment C have also been described in vitro and in vivo, involving the activation of Akt kinase and extracellular signal-regulated kinase (ERK) signaling cascades through neurotrophin tyrosine kinase (Trk) receptors. Although the precise mechanism of the molecular internalization of fragment C in neuronal cells remains unknown, fragment C could be internalized and translocated into the neuronal cytosol through a clathrin-mediated pathway dependent on proteins, such as dynamin and AP-2. In this review, the origins, molecular properties and possible signaling pathways of fragment C are reviewed to understand the biochemical characteristics of its intracellular and synaptic transport

Expedition 376 summary

Volcanic arcs are the surface expression of magmatic systems that result from subduction of mostly oceanic lithosphere at convergent plate boundaries. Arcs with a submarine component include intraoceanic arcs and island arcs that span almost 22,000 km on Earth’s surface, and the vast majority of them are located in the Pacific region. Hydrothermal systems hosted by submarine arc volcanoes commonly contain a large component of magmatic fluid. This magmatic-hydrothermal signature, coupled with the shallow water depths of arc volcanoes and their high volatile contents, strongly influences the chemistry of the fluids and resulting mineralization and likely has important consequences for the biota associated with these systems. The high metal content and very acidic fluids in these hydrothermal systems are thought to be important analogs to numerous porphyry copper and epithermal gold deposits mined today on land. During International Ocean Discovery Program (IODP) Expedition 376 (5 May–5 July 2018), a series of five sites was drilled on Brothers volcano in the Kermadec arc. The expedition was designed to provide the missing link (i.e., the third dimension) in our understanding of hydrothermal activity and mineral deposit formation at submarine arc volcanoes and the relationship between the discharge of magmatic fluids and the deep biosphere. Brothers volcano hosts two active and distinct hydrothermal systems: one is seawater influenced and the other is affected by magmatic fluids (largely gases). In total, 222.4 m of volcaniclastics and lavas were recovered from the five sites drilled, which include Sites U1527 and U1530 in the Northwest (NW) Caldera seawater-influenced hydrothermal field; Sites U1528 and U1531 in the magmatic fluid-influenced hydrothermal fields of the Upper and Lower Cones, respectively; and Site U1529, located within an area of low crustal magnetization that marks the West (W) Caldera upflow zone on the caldera floor. Downhole logging and borehole fluid sampling were completed at two sites, and two tests of a prototype turbine-driven coring system (designed by the Center for Deep Earth Exploration [CDEX] at Japan Agency for Marine-Earth Science and Technology [JAMSTEC]) for drilling and coring hard rocks were conducted. Core recovered from all five sites consists of dacitic volcaniclastics and lava flows with only limited chemical variability relative to the overall range in composition of dacites in the Kermadec arc. Pervasive alteration with complex and variable mineral assemblages attest to a highly dynamic hydrothermal system. The upper parts of several drill holes at the NW Caldera hydrothermal field are characterized by secondary mineral assemblages of goethite + opal + zeolites that result from low-temperature (<150°C) reaction of rock with seawater. At depth, NW Caldera Site U1527 exhibits a higher temperature (~250°C) secondary mineral assemblage dominated by chlorite + quartz + illite + pyrite. An older mineral assemblage dominated by diaspore + quartz + pyrophyllite + rutile at the bottom of Hole U1530A is indicative of acidic fluids with temperatures of ~230°–320°C. In contrast, the alteration assemblage at Site U1528 on the Upper Cone is dominated by illite + natroalunite + pyrophyllite + quartz + opal + pyrite, which attests to high-temperature reaction of rocks with acid-sulfate fluids derived from degassed magmatic volatiles and the disproportionation of magmatic SO2. These intensely altered rocks exhibit extreme depletion of major cation oxides, such as MgO, K2O, CaO, MnO, and Na2O. Furthermore, very acidic (as low as pH 1.8), relatively hot (≤236°C) fluids collected at 160, 279, and 313 meters below seafloor in Hole U1528D have chemical compositions indicative of magmatic gas input. In addition, preliminary fluid inclusion data provide evidence for involvement of two distinct fluids: phase-separated (modified) seawater and a ~360°C hypersaline brine, which alters the volcanic rock and potentially transports metals in the system. The material and data recovered during Expedition 376 provide new stratigraphic, lithologic, and geochemical constraints on the development and evolution of Brothers volcano and its hydrothermal systems. Insights into the consequences of the different types of fluid–rock reactions for the microbiological ecosystem elucidated by drilling at Brothers volcano await shore-based studies

Multidisciplinary scientific cruise to the Rio Grande Rise

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