|
| ||
|
|
||
Biological Sources (biological + source)
Selected AbstractsChitinolytic activity of endophytic Streptomyces and potential for biocontrolLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008M.C. Quecine Abstract Aims:, Biological sources for the control of plant pathogenic fungi remain an important objective for sustainable agricultural practices. Actinomycetes are used extensively in the pharmaceutical industry and agriculture owing to their great diversity in enzyme production. In the present study, therefore, we evaluated chitinase production by endophytic actinomycetes and the potential of this for control of phytopathogenic fungi. Methods and Results:, Endophytic Streptomyces were grown on minimum medium supplemented with chitin, and chitinase production was quantified. The strains were screened for any activity towards phytopathogenic fungi and oomycetes by a dual-culture in vitro assay. The correlation between chitinase production and pathogen inhibition was calculated and further confirmed on Colletotrichum sublineolum cell walls by scanning electron microscopy. Conclusions:, This paper reports a genetic correlation between chitinase production and the biocontrol potential of endophytic actinomycetes in an antagonistic interaction with different phytopathogens, suggesting that this control could occur inside the host plant. Significance and Impact of the Study:, A genetic correlation between chitinase production and pathogen inhibition was demonstrated. Our results provide an enhanced understanding of endophytic Streptomyces and its potential as a biocontrol agent. The implications and applications of these data for biocontrol are discussed. [source] Sources for sedimentary bacteriohopanepolyols as revealed by 16S rDNA stratigraphyENVIRONMENTAL MICROBIOLOGY, Issue 7 2008Marco J. L. Coolen Summary Bacteriohopanoids are widespread lipid biomarkers in the sedimentary record. Many aerobic and anaerobic bacteria are potential sources of these lipids which sometimes complicates the use of these biomarkers as proxies for ecological and environmental changes. Therefore, we applied preserved 16S ribosomal RNA genes to identify likely Holocene biological sources of bacteriohopanepolyols (BHPs) in the sulfidic sediments of the permanently stratified postglacial Ace Lake, Antarctica. A suite of intact BHPs were identified, which revealed a variety of structural forms whose composition differed through the sediment core reflecting changes in bacterial populations induced by large changes in lake salinity. Stable isotopic compositions of the hopanols formed from periodic acid-cleaved BHPs, showed that some were substantially depleted in 13C, indicative of their methanotrophic origin. Using sensitive molecular tools, we found that Type I and II methanotrophic bacteria (respectively Methylomonas and Methylocystis) were unique to the oldest lacustrine sediments (> 9400 years BP), but quantification of fossil DNA revealed that the Type I methanotrophs, including methanotrophs related to methanotrophic gill symbionts of deep-sea cold-seep mussels, were the main precursors of the 35-amino BHPs (i.e. aminopentol, -tetrol and -triols). After isolation of the lake ,3000 years ago, one Type I methanotroph of the ,methanotrophic gill symbionts cluster' remained the most obvious source of aminotetrol and -triol. We, furthermore, identified a Synechococcus phylotype related to pelagic freshwater strains in the oldest lacustrine sediments as a putative source of 2-methylbacteriohopanetetrol (2-Me BHT). This combined application of advanced geochemical and paleogenomical tools further refined our knowledge about Holocene biogeochemical processes in Ace Lake. [source] Pathogen safety of manufacturing processes for biological products: special emphasis on KOGENATE® BayerHAEMOPHILIA, Issue 2002D. C. Lee Summary., Manufacturers of human therapeutic proteins derived from biological sources continuously strive to improve the pathogen safety profiles of these products. Efforts to improve pathogen safety margins for these biological products are directed towards several areas within the manufacturing processes including: (a) sourcing and screening of raw materials (b) determining the potential for manufacturing processes to reduce pathogen titres, and (c) incorporating methods designed specifically to remove or inactivate contaminating pathogens. Methods that could potentially reduce pathogen titres are a major focus for many manufacturers. In general, these methods are grouped into two categories, pathogen clearance and pathogen inactivation. Assessments are performed on small-scale, laboratory simulations of the manufacturing process of interest that are spiked with a known amount of a selected pathogen. These studies provide estimates of the potential for a process step to remove or inactivate a particular pathogen. There are several pathogen clearance/inactivation methods that are inherent in manufacturing processes, however, some methods are intentionally incorporated into manufacturing for the sole purpose of reducing putative pathogen titres. Not only are well-known pathogens such as viruses targeted, but also suspected pathogens such as those associated with the transmissible spongiform encephalopathies (TSEs). The production processes for the isolation of several biological products, including recombinant KOGENATE® Bayer (Kogenate®FS), have been evaluated for the ability to reduce pathogen titres and/or have been designed to incorporate methods for reducing potential pathogen safety risks. Several processing steps with the potential to reduce pathogen titres have been identified. [source] Understanding immune cell trafficking patterns via in vivo bioluminescence imagingJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S39 2002Stefanie Mandl Abstract Cell migration is a key aspect of the development of the immune system and mediating an immune response. There is extensive and continual redistribution of cells to different anatomic sites throughout the body. These trafficking patterns control immune function, tissue regeneration, and host responses to insult. The ability to monitor the fate and function of cells, therefore, is imperative to both understanding the role of specific cells in disease processes and to devising rational therapeutic strategies. Determining the fate of immune cells and understanding the functional changes associated with migration and proliferation require effective means of obtaining in vivo measurements in the context of intact organ systems. A variety of imaging methods are available to provide structural information, such as X-ray CT and MRI, but only recently new tools have been developed that reveal cellular and molecular changes as they occur within living animals. We have pioneered one of these techniques that is based on the observations that light passes through mammalian tissues, and that luciferases can serve as internal biological sources of light in the living body. This method, called in vivo bioluminescence imaging, is a rapid and noninvasive functional imaging method that employs light-emitting reporters and external photon detection to follow biological processes in living animals in real time. This imaging strategy enables the studies of trafficking patterns for a variety of cell types in live animal models of human biology and disease. Using this approach we have elucidated the spatiotemporal trafficking patterns of lymphocytes within the body. In models of autoimmune disease we have used the migration of "pathogenic" immune cells to diseased tissues as a means to locally deliver and express therapeutic proteins. Similarly, we have determined the tempo of NK-T cell migration to neoplastic lesions and measured their life span in vivo. Using bioluminescence imaging individual groups of animals can be followed over time significantly reducing the number of animals per experiment, and improving the statistical significance of a study since changes in a given population can be studied over time. Such rapid assays that reveal cell fates in vivo will increase our basic understanding of the molecular signals that control these migratory pathways and will substantially speed up the development and evaluation of therapies. J. Cell. Biochem. Suppl. 39: 239,248, 2002. © 2002 Wiley-Liss, Inc. [source] Chip-mass spectrometry for glycomic studiesMASS SPECTROMETRY REVIEWS, Issue 2 2009Laura Bindila Abstract The introduction of micro- and nanochip front end technologies for electrospray mass spectrometry addressed a major challenge in carbohydrate analysis: high sensitivity structural determination and heterogeneity assessment in high dynamic range mixtures of biological origin. Chip-enhanced electrospray ionization was demonstrated to provide reproducible performance irrespective of the type of carbohydrate, while the amenability of chip systems for coupling with different mass spectrometers greatly advance the chip/MS technique as a versatile key tool in glycomic studies. A more accurate representation of the glycan repertoire to include novel biologically-relevant information was achieved in different biological sources, asserting this technique as a valuable tool in glycan biomarker discovery and monitoring. Additionally, the integration of various analytical functions onto chip devices and direct hyphenation to MS proved its potential for glycan analysis during the recent years, whereby a new analytical tool is on the verge of maturation: lab-on-chip MS glycomics. The achievements until early beginning of 2007 on the implementation of chip- and functional integrated chip/MS in systems glycobiology studies are reviewed here. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:223,253, 2009 [source] Assessment of Noise in Digital ElectrocardiogramsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2002VELISLAV BATCHVAROV BATCHVAROV, V., et al.: Assessment of Noise in Digital Electrocardiograms. Technically related noise in 12-lead ECGs recorded with ambulatory recorders has never been systematically compared with that in ECGs recorded with conventional ECGs. This study compared serial 10-second ECGs obtained in ten healthy men, age 22,45 years, who were recorded in the supine resting position using a (1) MAC VU recorder, (2) digital ambulatory SEER MC recorder with a Multi-Link detachable ECG cable, and (3) digital ambulatory SEER MC recorder with a light ambulatory ECG cable. In each ECG, averaged sinus rhythm cycles of the entire recording were realigned with the native signal and subtracted. The resulting "residuum" was quantified by computing its standard deviation and root mean square of successive differences (RMSSD). While the RMSSD residuum values were significantly lower with the MAC VU recorder (6.27 ± 0.98 ,V) than with the SEER MC recorder with either ECG cables (7.29 ± 1.31 and 7.17 ± 1.31 ,V, P < 0.003 and p < 0.02), the difference was practically negligible and there was no detectable difference in the standard deviation residuum values. The study concludes that valid ECG investigations of serial ECG testing may be conducted using the ambulatory SEER MC recorders providing the biological sources of ECG noise are controlled. The available technology for noise assessment suggests that studies involving advanced analysis of serial ECGs (e.g., of drug related changes), should incorporate objective characterisation of ECG quality. [source] Screening for disulfide-rich peptides in biological sources by carboxyamidomethylation in combination with differential matrix-assisted laser desorption/ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2001Susanne Neitz Peptides with biological functions often contain disulfide bridges connecting two cysteine residues. In an attempt to screen biological fluids for peptides containing cysteine residues, we have developed a sensitive and specific method to label cysteines selectively and detect the resulting molecular mass shift by differential mass spectrometry. First, reduction of disulfide bridges and carboxyamidomethylation of free thiols is adjusted to quantitatively achieve cysteine alkylation for complex peptide extracts. In a second step, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) before and after chemical derivatization is performed, followed by differential analysis to determine shifted peaks; shifted peaks belong to cysteine-containing peptides, other peaks remain unchanged. The number of cysteines can then be determined by the resulting molecular mass shift. Free, reduced cysteines are shifted by 57,u, two oxidized cysteines involved in disulfide bridges (cystine) result in a shift to higher mass per disulfide bridge of 116,u. Disulfide bridges connecting different amino acid chains like insulin break up during reduction. In this case, two peaks with lower molecular masses result from a single one in the unmodified sample. With this technique, we were able to identify cysteine-containing peptides and short fragments of proteins present in human blood filtrate. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||||||||