Azospirillum Genomes Reveal Transition of Bacteria from Aquatic to Terrestrial Environments

Fossil records indicate that life appeared in marine environments ∼3.5 billion years ago (Gyr) and transitioned to terrestrial ecosystems nearly 2.5 Gyr. Sequence analysis suggests that “hydrobacteria” and “terrabacteria” might have diverged as early as 3 Gyr. Bacteria of the genus Azospirillum are associated with roots of terrestrial plants; however, virtually all their close relatives are aquatic. We obtained genome sequences of two Azospirillum species and analyzed their gene origins. While most Azospirillum house-keeping genes have orthologs in its close aquatic relatives, this lineage has obtained nearly half of its genome from terrestrial organisms. The majority of genes encoding functions critical for association with plants are among horizontally transferred genes. Our results show that transition of some aquatic bacteria to terrestrial habitats occurred much later than the suggested initial divergence of hydro- and terrabacterial clades. The birth of the genus Azospirillum approximately coincided with the emergence of vascular plants on land

Produkcja krzemu ze źródeł alternatywnych

During the process of the rice hulls pyrolysis at the pilot plant the silicacarbon (SC) was produced containing 51.2% of total carbon, 38.7% of silicon dioxide and 7.6% of hydrocarbons. Its secondary heat treatment with air supply resulted in generation of the two products: SC-1 (50.4% of SiO2; 48.2% of С; 0.56% of Са; and 0.4% of Fe), and SC-2 (76.45% of SiO2; 22.1% of С; 0.95% of Са; and 0.55% of Fe). After treatment with the 1% HCl solution the content of Са and Fe in these products decreased to 0.15% and 0.16%, respectively. Silica gel (88.4% of SiO2, 11.0% of Н2О) and carbon (95% of С, 4.5% of SiO2) were produced from SC after its treatment with the NaOH solution. Characteristics of the result products were studied using the infrared spectroscopy and X-ray diffraction analysis. SC is a composite alloy formed by nanoparticles of amorphous carbon (~500Å) and silicon dioxide (100–200 Å). Carbon is presented by graphite-like (Gph), polynaphthenic (Nph) and hydrocarbon (Hph) phases. Amorphous SiO2 is presented by opal. Three types of charging materials with SiO2:С~2.5 proportion were produced from SC-1 and SC-2, from SC-1 and quartz, and from quartz and silica gel. At the pressure of 20 MPascal briquettes were produced from each charging material, which upon drying at air (100°С) and furnacing (300°С) in the inert atmosphere had the strength of 25-38 kg/cm2. After smelting the briquettes in an electric arc furnace, the silicon product with the content of 98-99% Si was produced. In industrial conditions after ladle refining the content of Са and Fe in silicon will be reduced down to 0.3–0.4%.W procesie pirolizy łuski ryżowej w instalacji pilotowej wyprodukowano silikakarbon (SC) zawierający 51,2% całkowitego węgla, 38,7% dwutlenku krzemu i 7,6% węglowodorów. Jego wtórna obróbka cieplna za pomocą powietrza doprowadziła do wytworzenia dwóch produktów: SC-1 (50,4% SiO2, 48,2% C, 0,56% Ca i 0,4% Fe) i SC-2 (76,45% SiO2, 22,1% C, 0,95% Ca i 0,55% Fe). Po obróbce 1% roztworem HCl zawartość Са i Fe w tych produktach obniżyła się odpowiednio do 0,15% i 0,16%. Żel krzemionkowy (88,4% SiO2, 11,0% Н2О) i węgiel (95% S, 4,5% SiO2) wytworzono z SC po traktowaniu roztworem NaOH. Charakterystykę produktów badano przy użyciu spektroskopii w podczerwieni i analizy dyfrakcji rentgenowskiej. SC jest stopem kompozytowym utworzonym z nanocząstek bezpostaciowego węgla (~ 500Å) i dwutlenku krzemu (100–200 Å). Węgiel jest reprezentowany przez fazy grafitopodobne (Gph), polinefeninowe (Nph) i węglowodorowe (Hph). Amorficzny SiO2 jest prezentowany przez opal. Trzy rodzaje materiałów z udziałem SiO2: С 2,5 zostały wytworzone z SC-1 i SC-2, z SC-1 i kwarcu oraz z kwarcu i żelu krzemionkowego. Brykiety wytworzono pod ciśnieniem 20 MPa po wysuszeniu na powietrzu (100°С) i w piecu (300°С) w atmosferze obojętnej. Brykiety miały wytrzymałość 25-38 kg/cm2. Po wytopieniu brykietu w elektrycznym piecu łukowym wytworzono produkt krzemowy o zawartości 98–99% Si. W warunkach przemysłowych po rafinacji zawartość Са i Fe w krzemie zostanie zmniejszona do 0,3–0,4%

Materiały węglowe z łupin ryżowych: produkcja i zastosowanie w przemyśle i rolnictwie

A solid carbonaceous material and a liquid product were produced by the rice husk pyrolysis. Chemical analysis and GC-MS were used to investigate the compositions of the prepared materials, respectively. X-ray, SEM, TEM, BET were applied to study the structure and textural properties of the carbonaceous material. It was determined that the solid product is a composite consisting of carbon (52%) and silicon dioxide (31%) nanoparticles. Therefore, it was named a silicon-carbon. The liquid product is a water solution containing various organic compounds (carboxylic acids, phenols, ketones, alcohols and ethers, cyclic aliphatic hydrocarbons, heterocyclic compounds). The possibility to apply the solid carbonaceous material as a reducing agent and a sorbent and the liquid organic product as a flotation reagent was determined in the electro thermal smelting process, sorption and flotation processes. Veterinary and toxicology studies were performed to estimate toxicity of solid carbonaceous material and possibility to apply it as a feed additive. It was shown, that due to its chemical composition the silicon-carbon is a complex raw material for metallurgical silicon, aluminum-free and titanium-free ferrosilicium, and silicon carbide production. The produced sorbent had high rare and heavy metals adsorption capacity. The solid carbonaceous material, that was found to be non-toxic, was an effective feed additive and improved quality of laying hens and broiler chickens. The liquid product had properties of a blowing agent in the flotation of lead-zinc ores. It was concluded that both rice husk derived solid and liquid carbonaceous materials are economically effective alternative materials for various technological processes and agriculture.Stały materiał węglowy i produkt płynny wytworzono prowadząc pirolizę łusek ryżu. Do zbadania składu otrzymanych materiałów wykorzystano odpowiednio analizę chemiczną i GC-MS. W celu zbadania struktury i budowy materiału węglowego zastosowano badania rentgenowskie, SEM, TEM i BET. Stwierdzono, że produkt stały jest kompozytem złożonym z węgla (52%) i nanocząstek dwutlenku krzemu (31%). Dlatego został nazwany krzemo-węglem. Produktem ciekłym był roztwór wodny zawierający różne związki organiczne (kwasy karboksylowe, fenole, ketony, alkohole i etery, cykliczne węglowodory alifatyczne, związki heterocykliczne). Zbadano możliwość nanoszenia stałego materiału węglowego jako środka redukującego i sorbentu, natomiast zastosowanie dla ciekłego produktu organicznego jako odczynnika flotacyjnego weryfikowano w procesie elektrotermicznego wytapiania oraz w procesach sorpcji i flotacji. Przeprowadzono również badania weterynaryjne i toksykologiczne w celu oceny toksyczności stałego materiału węglowego i możliwości jego zastosowania jako dodatku paszowego. Wykazano, że ze względu na skład chemiczny, krzemo-węgiel stanowi kompleksowy surowiec do produkcji metalurgicznego krzemu, węglika krzemu oraz żelazokrzemu bez dodatku glinu i tytanu. Produkowany sorbent miał dużą zdolność adsorpcji metali rzadkich i ciężkich. Stały materiał węglowy, który okazał się być nietoksyczny, był skutecznym dodatkiem do pasz poprawiając jakość kur niosek i brojlerów. Produkt ciekły wykazywał właściwości środka porotwórczego we flotacji rud ołowiu i cynku. Stwierdzono, że zarówno stały jak i ciekły materiał węglowy pochodzący z łupin ryżowych są ekonomicznie efektywnymi materiałami dla różnych procesów technologicznych i rolnictwa

Rumen Microbial Population Dynamics during Adaptation to a High-Grain Diet ▿ †

High-grain adaptation programs are widely used with feedlot cattle to balance enhanced growth performance against the risk of acidosis. This adaptation to a high-grain diet from a high-forage diet is known to change the rumen microbial population structure and help establish a stable microbial population within the rumen. Therefore, to evaluate bacterial population dynamics during adaptation to a high-grain diet, 4 ruminally cannulated beef steers were adapted to a high-grain diet using a step-up diet regimen containing grain and hay at ratios of 20:80, 40:60, 60:40, and 80:20. The rumen bacterial populations were evaluated at each stage of the step-up diet after 1 week of adaptation, before the steers were transitioned to the next stage of the diet, using terminal restriction fragment length polymorphism (T-RFLP) analysis, 16S rRNA gene libraries, and quantitative real-time PCR. The T-RFLP analysis displayed a shift in the rumen microbial population structure during the final two stages of the step-up diet. The 16S rRNA gene libraries demonstrated two distinct rumen microbial populations in hay-fed and high-grain-fed animals and detected only 24 common operational taxonomic units out of 398 and 315, respectively. The 16S rRNA gene libraries of hay-fed animals contained a significantly higher number of bacteria belonging to the phylum Fibrobacteres, whereas the 16S rRNA gene libraries of grain-fed animals contained a significantly higher number of bacteria belonging to the phylum Bacteroidetes. Real-time PCR analysis detected significant fold increases in the Megasphaera elsdenii, Streptococcus bovis, Selenomonas ruminantium, and Prevotella bryantii populations during adaptation to the high-concentrate (high-grain) diet, whereas the Butyrivibrio fibrisolvens and Fibrobacter succinogenes populations gradually decreased as the animals were adapted to the high-concentrate diet. This study evaluates the rumen microbial population using several molecular approaches and presents a broader picture of the rumen microbial population structure during adaptation to a high-grain diet from a forage diet

Novelty and Uniqueness Patterns of Rare Members of the Soil Biosphere ▿ †

Soil bacterial communities typically exhibit a distribution pattern in which most bacterial species are present in low abundance. Due to the relatively small size of most culture-independent sequencing surveys, a detailed phylogenetic analysis of rare members of the community is lacking. To gain access to the rarely sampled soil biosphere, we analyzed a data set of 13,001 near-full-length 16S rRNA gene clones derived from an undisturbed tall grass prairie soil in central Oklahoma. Rare members of the soil bacterial community (empirically defined at two different abundance cutoffs) represented 18.1 to 37.1% of the total number of clones in the data set and were, on average, less similar to their closest relatives in public databases when compared to more abundant members of the community. Detailed phylogenetic analyses indicated that members of the soil rare biosphere either belonged to novel bacterial lineages (members of five novel bacterial phyla identified in the data set, as well as members of multiple novel lineages within previously described phyla or candidate phyla), to lineages that are prevalent in other environments but rarely encountered in soil, or were close relatives to more abundant taxa in the data set. While a fraction of the rare community was closely related to more abundant taxonomic groups in the data set, a significant portion of the rare biosphere represented evolutionarily distinct lineages at various taxonomic cutoffs. We reason that these novelty and uniqueness patterns provide clues regarding the origins and potential ecological roles of members of the soil's rare biosphere

Time-resolved quantum beats in the fluorescence of helium resonantly excited by XUV radiation

We report on the observation of time-resolved quantum beats in the helium fluorescence from the transition 1s3p -> 1s2s, where the initial state is excited by XUV free-electron laser radiation. The quantum beats originate from the Zeeman splitting of the magnetic substates due to an external magnetic field. We perform a systematic study of this effect and discuss the possibilities of studying this phenomenon in the XUV and x-ray regime

Time-resolved quantum beats in the fluorescence of helium resonantly excited by XUV radiation

We report on the observation of time-resolved quantum beats in the helium fluorescence from the transition 1s3p → 1s2s, where the initial state is excited by XUV free electron laser radiation. The quantum beats originate from the Zeeman splitting of the magnetic substates due to an external magnetic field. We perform a systematic study of this effect and discuss the possibilities of studying this phenomenon in the XUV and x-ray regime