Caldicellulosiruptor obsidiansis sp. nov., an Anaerobic,Extremely Thermophilic,Cellulolytic Bacterium Isolated from Obsidian Pool,Yellowstone National Park

A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47^T, was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 μm long by 0.2 μm wide and grew at temperatures between 55 and 85°C, with the optimum at 78°C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h⁻¹. The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47^T was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H₂, and CO₂, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47^T within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073).Cellulosic biomass will likely serve as an important source of stored renewable energy in the future. However, improvements in overcoming the recalcitrance of lignocellulosic materials to enzymatic hydrolysis must be made in order to efficiently convert biomass to liquid fuels (23, 27). Members of the genera Caldicellulosiruptor and Anaerocellum are obligatory anaerobic, extreme thermophiles within the Firmicutes and are known to express heat-stable extracellular enzyme systems for breaking down biomass (4). In addition, both hexose and pentose sugars can be utilized for fermentation (12, 16, 19, 28). Given these properties, recent studies have focused on the use of extreme thermophiles for biomass conversion to fuels, including Caldicellulosiruptor saccharolyticus as a biocatalyst for hydrogen production from biomass (10, 26) and A. thermophilum (also known as Caldicellulosiruptor bescii), which has been evaluated for growth on plant biomass without physical or chemical pretreatment (28, 29).A number of isolated strains of Caldicellulosiruptor have been described thus far, with several organisms originating from Icelandic hot springs (3, 14, 17, 18); the geothermal region of Kamchatka (15, 24); thermal features in New Zealand (19); and solar-heated freshwater ponds in Owens Valley, CA (9). The environmental parameters for growth appear to be fairly uniform for these organisms which prefer circumneutral to slightly alkaline pH and temperatures ranging from 60 to 83°C. None of the described isolates form spores, and all strains are heterotrophic obligate anaerobes which utilize a broad range of carbohydrates for fermentative growth. Complete genome sequences are available for C. saccharolyticus (26) and Anaerocellum thermophilum (28).Thus far, no species of Caldicellulosiruptor have been isolated and characterized from the major geothermal formations within Yellowstone National Park (YNP), WY. Recent enrichment and isolation attempts revealed a high abundance of cellulolytic organisms from hot springs within the Mud Volcano region of YNP. Using a high-throughput isolation method based on flow cytometry, a total of 53 isolates of Caldicellulosiruptor, based on small subunit rRNA analysis, were isolated from Obsidian Pool. Secondary screening of these strains provided an organism with rapid growth kinetics on pretreated biomass substrates as well as crystalline cellulose and xylan at 80°C. Based on small subunit rRNA analysis, genomic sequence comparisons, and phenotypic properties, we propose this organism as Caldicellulosiruptor obsidiansis OB47^T sp. nov., which is named in reference to the location from which it was isolated, Obsidian Pool, YNP.     

Local gating of information processing through the thalamus

Inhibitory sculpting of afferent signals in the thalamus is exerted by two types of neurons using gamma-amino butyric acid (GABA) as neurotransmitter. Of them, local-circuit neurons exert their functions via two outputs: axons and presynaptic dendrites. In this issue of Neuron, Govindaiah and Cox reveal that synaptic activation of metabotropic glutamate receptors selectively increases the output of presynaptic dendrites of local interneurons in rat visual thalamus, without affecting the axonal output.     

Induction of complement-fixing autoantibodies against type VII collagen results in subepidermal blistering in mice

Experimental models reproducing an autoimmune response resulting in skin blistering in immunocompetent animals are lacking. Epidermolysis bullosa acquisita (EBA) is a bullous skin disease caused by autoantibodies to type VII collagen. In this study, we describe an active disease model of EBA by immunizing mice of different strains with murine type VII collagen. All mice developed circulating IgG autoantibodies that recognized type VII collagen and bound to the lamina densa of the dermal-epidermal junction. Importantly, subepidermal blisters developed in 82% of SJL-1, 56% of BALB/c mice, and 45% of Fc gammaRIIb-deficient mice, but not in SKH-1 mice. In susceptible animals, deposits of IgG1, IgG2, and complement C3 were detected at the dermal-epidermal junction. In contrast, in the nondiseased mice, tissue-bound autoantibodies were predominantly of the IgG1 subclass and complement activation was weak or absent. This active disease model reproduces in mice the clinical, histopathological, and immunopathological findings in EBA patients. This robust experimental system should greatly facilitate further studies on the pathogenesis of EBA and the development of novel immunomodulatory therapies for this and other autoimmune diseases.     

Early Prediction of Sepsis Incidence in Critically Ill Patients Using Specific Genetic Polymorphisms

Several diagnostic methods for the evaluation and monitoring were used to find out the pro-inflammatory status, as well as incidence of sepsis in critically ill patients. One such recent method is based on investigating the genetic polymorphisms and determining the molecular and genetic links between them, as well as other sepsis-associated pathophysiologies. Identification of genetic polymorphisms in critical patients with sepsis can become a revolutionary method for evaluating and monitoring these patients. Similarly, the complications, as well as the high costs associated with the management of patients with sepsis, can be significantly reduced by early initiation of intensive care.     

The small, the forgotten and the dead: highway impact on vertebrates and its implications for mitigation strategies

Roads affect wildlife in many ways, and probably the most conspicuous of these is by producing roadkills. In Mexico few studies have addressed this issue. In the present study, we look at the richness and abundance of vertebrate roadkills along a 14 km stretch of the Amozoc-Cantona-Perote highway, at the border of the states of Veracruz and Puebla and across two environments: shrubland and grassland. The highway was sampled on 34 days between June 2010 and March 2011. A total of 946 animals were recorded as killed by traffic, and belonged to 58 species. Ten of these are under some protection status by Mexican law. Diversity values for shrubland were D = 0.52 and for grassland D = 1.2, both with Bray–Curtis similarity values of I_bc = 0.12 and complementarity (C_AB) was 98.5. The most common roadkilled animals were rodents (genus Peromyscus). We estimate that 11,899 vertebrates are killed annually in this section of the highway. This study highlights the need for designing and applying policies and actions for road construction and maintenance that, together with driver’s education, will allow us to increase landscape connectivity and decrease wildlife roadkills.     

Immunohistochemical localization of caspase-3, caspase-9 and Bax in U87 glioblastoma xenografts

Development of new therapies for glioblastoma requires animal models that mimic the biological characteristics of human brain tumors. On the other hand, potential antitumoral effects of a new therapeutic strategy are often established by evaluation of tumor cells apoptosis. Caspases are key mediators in the regulation and execution of apoptosis. Caspase-9 is activated during the intrinsic pathway downstream of mitochondria while caspase-3 is an effector caspase that initiates degradation of the cell in the final stages of apoptosis. Bax is a pro-apoptotic member of the Bcl-2 family that play key roles in the regulation of intrinsic apoptotic signaling. In the present study we investigated the immunohistochemical distribution of caspase 3, 9 and Bax in intracranial U87 glioblastoma xenograft. Immunohistochemistry showed that the glioblastoma xenografts contain cells positive for caspase-3, caspase-9, and Bax.     

Physicochemical and Rheological Properties of Romanian Honeys

The purpose of this work was to investigate the physicochemical and rheological properties of Romanian honey, and particularly to analyze the influence of moisture content, °Brix concentration and temperature. All the samples were characterized to determine their physicochemical (moisture, °Brix, pH, ash, conductivity, colour, 5-hydroxymethylfurfural content, sugar content, diastase activity) and bioactive (antioxidant activity, total phenols content and total flavonoids content) parameters. All the investigated honeys displayed Newtonian behaviour at all temperatures. Four experimental viscosity models were checked using the experimental data to correlate the influence of temperature upon honey viscosity; The William-Landel-Ferry model was much suitable than Power Law, Arrhenius and Vogel-Taumman-Fulcher models for temperature-viscosity modelling. By using the polynomial modeling method, it was possible to develop a mathematical model to describe honey viscosity in the function of temperature and chemical composition. The model achieved, developed from the viscosity, temperature and chemical composition allows predicting the evolution of the dynamic viscosity.     

On mathematical characterization of mutations

The aim of the present paper is to give for the mutations from genetics a mathematical treatment similar to that utilized for the perturbation in communication theory. The transformations induced by mutations both on codons and on amino acids are investigated.     

Sequence‐dependent modelling of local DNA bending phenomena: curvature prediction and vibrational analysis

Bending is a local conformational micropolymorphism of DNA in which the original B-DNA structure is only distorted but not extensively modified. Bending can be predicted by simple static geometry models as well as by a recently developed elastic model that incorporate sequence dependent anisotropic bendability (SDAB). The SDAB model qualitatively explains phenomena including affinity of protein binding, kinking, as well as sequence-dependent vibrational properties of DNA. The vibrational properties of DNA segments can be studied by finite element analysis of a model subjected to an initial bending moment. The frequency spectrum is obtained by applying Fourier analysis to the displacement values in the time domain. This analysis shows that the spectrum of the bending vibrations quite sensitively depends on the sequence, for example the spectrum of a curved sequence is characteristically different from the spectrum of straight sequence motifs of identical basepair composition. Curvature distributions are genome-specific, and pronounced differences are found between protein-coding and regulatory regions, respectively, that is, sites of extreme curvature and/or bendability are less frequent in protein-coding regions. A WWW server is set up for the prediction of curvature and generation of 3D models from DNA sequences (http://www.icgeb.trieste.it/dna).This revised version was published online in October 2005 with corrections to the Cover Date.