1,636 research outputs found

    Coculture fermentation of banana agro-waste to ethanol by cellulolytic thermophilic Clostridium thermocellum CT2

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    Banana is a major cash crop of many regions generating good amount of waste after harvest. This agro waste which is left for natural degradation is used as substrate for single step ethanol fermentation by thermophilic, cellulolytic, ethanologenic Clostridium thermocellum CT2, a new culture isolated from elephant droppings. Scanning electron microscopic pictures clearly indicate cellulolysis and close interaction of selected isolate CT2 with cellulose. The optimum conditions for cellulose fermentation were 60°C, pH 7.5, inoculums size 5% and incubation time 5 days. Ethanol produced and reducing sugars were estimated by gas chromatography. Clostridium thermosaccharolyticum HG8 and Thermoanaerobacter ethanolicus ATCC 31937 were used in coculture fermentation with CT2. Coculture fermentation of CT2 with HG8 was more efficient in terms of ethanol production, cellulose degradation and reducing sugars utilization. A maximum ethanol yield of 0.41g/g substrate used was obtained oncoculturing CT2 with HG8 on alkali treated banana waste. Coculture was active even at substrate concentrations up to 100 g/l, a maximum ethanol of 22 g/l was obtained at 100 g/l substrate concentration on coculturing CT2 with HG8. This is the first report on anaerobic single step conversionof banana waste to ethanol by C. thermocellum

    The very lithium rich post-AGB SB2 binary HD172481

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    Double lined spectroscopic binaries in an evolved stage of evolution are expected to be extremely rare since they must consist of equally luminous and thus almost equally evolved objects, which requires an extremely similar initial mass. In this contribution we discuss such rare double evolved SB2 system: HD172481. This binary includes an F-type post-AGB object and an M-type AGB companion. The spectrum shows a surprisingly strong LiI 670.8nm line with an equivalent width of 54mA yielding a lithium abundance of log(Li)=3.6. Several explanations for this huge lithium content are explored.Comment: 7 pages, 5 figures, to appear in the proceedings of: "Post-AGB Objects (Proto-Planetary Nebulae) as a Phase of Stellar Evolution", held in Torun, Poland, July 5-7, 2000; eds. R. Szczerba, R. Tylenda, and S.K. Gorny. See also the accepted A&A paper at http://xxx.lanl.gov/abs/astro-ph/001048

    Simultaneous TE Analysis of 19 Heliconiine Butterflies Yields Novel Insights into Rapid TE-Based Genome Diversification and Multiple SINE Births and Deaths

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    Transposable elements (TEs) play major roles in the evolution of genome structure and function. However, because of their repetitive nature, they are difficult to annotate and discovering the specific roles they may play in a lineage can be a daunting task. Heliconiine butterflies are models for the study of multiple evolutionary processes including phenotype evolution and hybridization. We attempted to determine how TEs may play a role in the diversification of genomes within this clade by performing a detailed examination of TE content and accumulation in 19 species whose genomes were recently sequenced. We found that TE content has diverged substantially and rapidly in the time since several subclades shared a common ancestor with each lineage harboring a unique TE repertoire. Several novel SINE lineages have been established that are restricted to a subset of species. Furthermore, the previously described SINE, Metulj, appears to have gone extinct in two subclades while expanding to significant numbers in others. This diversity in TE content and activity has the potential to impact how heliconiine butterflies continue to evolve and diverge

    Neuroactive steroids in depression and anxiety disorders: Clinical studies

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    Certain neuroactive steroids modulate ligand-gated ion channels via non-genomic mechanisms. Especially 3 alpha-reduced pregnane steroids are potent positive allosteric modulators of the gamma-aminobutyric acid type A (GABA(A)) receptor. During major depression, there is a disequilibrium of 3 alpha-reduced neuroactive steroids, which is corrected by clinically effective pharmacological treatment. To investigate whether these alterations are a general principle of successful antidepressant treatment, we studied the impact of nonpharmacological treatment options on neuroactive steroid concentrations during major depression. Neither partial sleep deprivation, transcranial magnetic stimulation, nor electroconvulsive therapy affected neuroactive steroid levels irrespectively of the response to these treatments. These studies suggest that the changes in neuroactive steroid concentrations observed after antidepressant pharmacotherapy more likely reflect distinct pharmacological properties of antidepressants rather than the clinical response. In patients with panic disorder, changes in neuroactive steroid composition have been observed opposite to those seen in depression. However, during experimentally induced panic induction either with cholecystokinine-tetrapeptide or sodium lactate, there was a pronounced decline in the concentrations of 3 alpha-reduced neuroactive steroids in patients with panic disorder, which might result in a decreased GABAergic tone. In contrast, no changes in neuroactive steroid concentrations could be observed in healthy controls with the exception of 3 alpha,5 alpha-tetrahydrodeoxycorticosterone. The modulation of GABA(A) receptors by neuroactive steroids might contribute to the pathophysiology of depression and anxiety disorders and might offer new targets for the development of novel anxiolytic compounds. Copyright (c) 2006 S. Karger AG, Basel

    Evaluation of the bacterial diversity of Pressure ulcers using bTEFAP pyrosequencing

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    <p>Abstract</p> <p>Background</p> <p>Decubitus ulcers, also known as bedsores or pressure ulcers, affect millions of hospitalized patients each year. The microflora of chronic wounds such as ulcers most commonly exist in the biofilm phenotype and have been known to significantly impair normal healing trajectories.</p> <p>Methods</p> <p>Bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP), a universal bacterial identification method, was used to identify bacterial populations in 49 decubitus ulcers. Diversity estimators were utilized and wound community compositions analyzed in relation to metadata such as Age, race, gender, and comorbidities.</p> <p>Results</p> <p>Decubitus ulcers are shown to be polymicrobial in nature with no single bacterium exclusively colonizing the wounds. The microbial community among such ulcers is highly variable. While there are between 3 and 10 primary populations in each wound there can be hundreds of different species present many of which are in trace amounts. There is no clearly significant differences in the microbial ecology of decubitus ulcer in relation to metadata except when considering diabetes. The microbial populations and composition in the decubitus ulcers of diabetics may be significantly different from the communities in non-diabetics.</p> <p>Conclusions</p> <p>Based upon the continued elucidation of chronic wound bioburdens as polymicrobial infections, it is recommended that, in addition to traditional biofilm-based wound care strategies, an antimicrobial/antibiofilm treatment program can be tailored to each patient's respective wound microflora.</p

    The accuracy of MRI in the detection of Lumbar Disc Containment

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    <p>Abstract</p> <p>Background</p> <p>MRI has proven to be an extremely valuable tool in the assessment of normal and pathological spinal anatomy. Accordingly, it is commonly used to assess containment of discal material by the outer fibers of the anulus fibrosus and posterior longitudinal ligaments. Determination of such containment is important to determine candidacy for intradiscal techniques and has prognostic significance. The accuracy of MRI in detecting containment has been insufficiently documented.</p> <p>Methods</p> <p>The MRI's of fifty consecutive patients undergoing open lumbar microdiscectomy were prospectively evaluated for disc containment by a neuroradiologist and senior spinal surgeon using criteria available in the literature and the classification of Macnab/McCulloch. An independent surgeon then performed the surgery and documented the actual containment status using the same methods. Statistical evaluation of accuracy was undertaken.</p> <p>Results</p> <p>MRI was found to be 72% sensitive, 68% specific, and 70% accurate in detecting containment status of lumbar herniated discs.</p> <p>Conclusion</p> <p>MRI may be inaccurate in assessing containment status of lumbar disc herniations in 30% of cases. Given the importance of containment for patient selection for indirect discectomy techniques and intradiscal therapies, coupled with prognostic significance; other methods to assess containment should be employed to assess containment when such alternative interventions are being considered.</p

    Altered Chromosomal Positioning, Compaction, and Gene Expression with a Lamin A/C Gene Mutation

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    Lamins A and C, encoded by the LMNA gene, are filamentous proteins that form the core scaffold of the nuclear lamina. Dominant LMNA gene mutations cause multiple human diseases including cardiac and skeletal myopathies. The nuclear lamina is thought to regulate gene expression by its direct interaction with chromatin. LMNA gene mutations may mediate disease by disrupting normal gene expression.To investigate the hypothesis that mutant lamin A/C changes the lamina's ability to interact with chromatin, we studied gene misexpression resulting from the cardiomyopathic LMNA E161K mutation and correlated this with changes in chromosome positioning. We identified clusters of misexpressed genes and examined the nuclear positioning of two such genomic clusters, each harboring genes relevant to striated muscle disease including LMO7 and MBNL2. Both gene clusters were found to be more centrally positioned in LMNA-mutant nuclei. Additionally, these loci were less compacted. In LMNA mutant heart and fibroblasts, we found that chromosome 13 had a disproportionately high fraction of misexpressed genes. Using three-dimensional fluorescence in situ hybridization we found that the entire territory of chromosome 13 was displaced towards the center of the nucleus in LMNA mutant fibroblasts. Additional cardiomyopathic LMNA gene mutations were also shown to have abnormal positioning of chromosome 13, although in the opposite direction.These data support a model in which LMNA mutations perturb the intranuclear positioning and compaction of chromosomal domains and provide a mechanism by which gene expression may be altered

    Genome characterization of a new strain of peanut chlorotic streak virus causing chlorotic vein banding disease of groundnut (Arachis hypogaea L.) in India

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    The double-stranded DNA of the chlorotic vein banding isolate of peanut chlorotic streak caulimovirus (PC1SV-CVB), isolated from purified virus, resolved into circular and linear molecules similar to those of other caulimoviruses. A physical map of viral DNA was constructed, which showed the PCLSV-CVB DNA to be circular and composed of approximately 8.2 kbp. A number of restriction sites were found to be shared with a similar caulimovirus, PCLSV. Nevertheless, several differences between physical maps of the 2 viruses suggested that PCLSV-CVB should be considered as a distinct strain of PCLSV. Bam HI-cleaved PCLSV-CVB DNA was cloned into pUC 118 and was infectious when cleaved from the cloning vector and inoculated onto Vigna unguiculata [cowpeas]

    Development of a modified floristic quality index as a rapid habitat assessment method in the northern Everglades

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    Floristic quality assessments (FQA) using floristic quality indices (FQIs) are useful tools for assessing and comparing vegetation communities and related habitat condition. However, intensive vegetation surveys requiring significant time and technical expertise are necessary, which limits the use of FQIs in environmental monitoring programs. This study modified standard FQI methods to develop a rapid assessment method for characterizing and modeling change in wetland habitat condition in the northern Everglades. Method modifications include limiting vegetation surveys to a subset of taxa selected as indicators of impact and eliminating richness and/or abundance factors from the equation. These modifications reduce the amount of time required to complete surveys and minimizes misidentification of species, which can skew results. The habitat characterization and assessment tool (HCAT) developed here is a FQA that uses a modified FQI to detect and model changes in habitat condition based on vegetation communities, characterize levels of impact as high, moderate, or low, provide predictive capabilities for assessing natural resource management or water management operation alternatives, and uniquely links a FQI with readily accessible environmental data. For application in the northern Everglades, surface water phosphorus concentrations, specific conductivity, distance from canal, and days since dry (5-year average) explained 67% of the variability in the dataset with \u3e 99.9% confidence. The HCAT approach can be used to monitor, assess, and evaluate habitats with the objective of informing management decisions (e.g., as a screening tool) to maximize conservation and restoration of protected areas and is transferable to other wetlands with additional modification
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