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Various Organisms (various + organism)
Selected AbstractsStudying natural structural protein fibers by solid-state nuclear magnetic resonanceCONCEPTS IN MAGNETIC RESONANCE, Issue 1 2009Alexandre A. Arnold Abstract As a consequence of evolutionary pressure, various organisms have developed structural fibers displaying a range of exceptional mechanical properties adapted specifically to their functions. An understanding of these properties at the molecular level requires a detailed description of local structure, orientation with respect to the fiber and size of constitutive units, and dynamics on various timescales. The size and lack of long-range order in these protein systems constitute an important challenge to classical structural techniques such as high-resolution NMR and X-ray diffraction. Solid-state NMR overcomes these constraints and is uniquely suited to the study of these inherently disordered systems. Solid-state NMR experiments developed or applied to determine structure, orientation, and dynamics of these complex proteins will be reviewed and illustrated through examples of their applications to fibers such as spider and silkworm silks, collagen, elastin, and keratin. © 2009 Wiley Periodicals, Inc. Concepts Magn Reson Part A 34A: 24,27, 2009. [source] Colloidal Films That Mimic CiliaADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Fang Liu Abstract Cilia are wavy hair-like structures that extend outward from surfaces of various organisms. They are classified into two general categories, primary cilia, which exhibit sensing attributes, and motile cilia, which exert mechanical forces. A new poly(2-(N,N -dimethylamino)ethyl methacrylate- co -n-butyl acrylate- co - N,N -(dimethylamino) azobenzene acrylamide) (p(DMAEMA/nBA/DMAAZOAm) copolymer is prepared using colloidal synthesis, which, upon coalescence, form films capable of generating surfaces with cilia-like features. While film morphological features allow the formation of wavy whiskers, the chemical composition of the copolymer facilitates chemical, thermal, and electromagnetic responses manifested by simultaneous shape and color changes as well as excitation wavelength dependent fluorescence. These studies demonstrate that synthetically produced polymeric films can exhibit combined thermal, chemical, and electromagnetic sensing leading to locomotive and color responses, which may find numerous applications in sensing devices, intelligent actuators, defensive mechanisms, and others. [source] Dietary restriction and aging, 2009AGING CELL, Issue 2 2010Subhash D. Katewa Summary Dietary restriction (DR) is a robust nongenetic, nonpharmacological intervention that is known to increase active and healthy lifespan in a variety of species. Despite a variety of differences in the protocols and the way DR is carried out in different species, conserved relationships are emerging among multiple species. 2009 saw the field of DR mature with important mechanistic insights from multiple species. A report of lifespan extension in rapamycin-treated mice suggested that the TOR pathway, a conserved mediator of DR in invertebrates, may also be critical to DR effects in mammals. 2009 also saw exciting discoveries related to DR in various organisms including yeast, worms, flies, mice, monkeys and humans. These studies complement each other and together aim to deliver the promise of postponing aging and age-related diseases by revealing the underlying mechanisms of the protective effects of DR. Here, we summarize a few of the reports published in 2009 that we believe provide novel directions and an improved understanding of dietary restriction. [source] Impacts of Shewanella oneidensis c -type cytochromes on aerobic and anaerobic respirationMICROBIAL BIOTECHNOLOGY, Issue 4 2010Haichun Gao Summary Shewanella are renowned for their ability to utilize a wide range of electron acceptors (EA) for respiration, which has been partially accredited to the presence of a large number of the c -type cytochromes. To investigate the involvement of c -type cytochrome proteins in aerobic and anaerobic respiration of Shewanella oneidensis Mr -1, 36 in-frame deletion mutants, among possible 41 predicted, c -type cytochrome genes were obtained. The potential involvement of each individual c -type cytochrome in the reduction of a variety of EAs was assessed individually as well as in competition experiments. While results on the well-studied c -type cytochromes CymA(SO4591) and MtrC(SO1778) were consistent with previous findings, collective observations were very interesting: the responses of S. oneidensis Mr -1 to low and highly toxic metals appeared to be significantly different; CcoO, CcoP and PetC, proteins involved in aerobic respiration in various organisms, played critical roles in both aerobic and anaerobic respiration with highly toxic metals as EA. In addition, these studies also suggested that an uncharacterized c -type cytochrome (SO4047) may be important to both aerobiosis and anaerobiosis. [source] A new antimicrobial peptide isolated from Oudneya africana seedsMICROBIOLOGY AND IMMUNOLOGY, Issue 12 2009Riadh Hammami ABSTRACT Oudneya africana R. Br. (Brassicaceae), a wild-growing plant in the arid region of Tunisia, is used in ethno-medicinal treatment of microbial infections. Validation of ethno-therapeutic claims pertaining to the plant was sought by investigating its antimicrobial activity. A proteinaceous extract of the seeds, called AS-3000, showed activity against various organisms including L. monocytogenes, E. coli, B. subtilis, E. hirae, P. aeruginosa, S. aureus and C. albicans. Extract AS-3000 exhibited a synergistic effect against L. ivanovii when combined with vancomycin or chloramphenicol. The post-antibiotic inhibitory effect of the ampicillin/AS-3000 combination was 2.3-fold greater than for the antibiotic alone. The mode of action of AS-3000 on Listeria and Escherichia was visible using SEM. These results support the use of O. africana for treating microbial infections. [source] Correlation of Minimum Inhibitory Concentrations Toward Oral Bacterial Growth Based on the Abraham ModelMOLECULAR INFORMATICS, Issue 10 2006Christina Mintz Abstract The Abraham solvation parameter model is used to construct mathematical correlations for describing the minimum inhibitory concentration of organic compounds for growth inhibition toward Porphyromonas gingivalis, Selenomonas artemidis, and Streptococcus sorbrinius. The derived mathematical correlations describe the observed published inhibitory data to within an overall average standard deviation of approximately 0.30 log units. A principal component analysis, shows that the derived equations for the three growth inhibitions are quite close to each other, are near to some, but not to all, equations for aqueous toxicity toward various organisms, and are quite far from most equations for water to solvent partition. A further analysis suggests that the three growth inhibition systems behave as though a solute is transferred from water to an environment that is still quite water-like. [source] Dose,response effects of clove oil from Syzygium aromaticum on the root-knot nematode Meloidogyne incognita,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2008Susan LF Meyer Abstract BACKGROUND: Clove oil, derived from the plant Syzygium aromaticum(L.) Merr. & Perry, is active against various organisms, and was prepared in a soy lecithin/detergent formulation to determine concentrations active against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. RESULTS: In microwell assays, the mean effective clove oil concentration that reduced egg hatch by 50% (EC50) was 0.097% (v/v) clove oil; the EC50 for second-stage juvenile (J2) viability was 0.145% clove oil (compared with carrier control treatments). Volatiles from 5.0% clove oil reduced nematode egg hatch in water by 30%, and decreased viability of hatched J2 by as much as 100%. Reductions were not as large with nematodes in carrier. In soil trials with J2 recovered from Baermann funnels, the EC50 = 0.192% clove oil (compared with water controls). CONCLUSION: The results demonstrated that the tested formulation is active against M. incognita eggs and J2, that the EC50 values for J2 in the microwell studies and the soil recovery tests were similar to each other and that direct contact with the clove oil is needed for optimal management results with this natural product. Published in 2007 by John Wiley & Sons, Ltd. [source] Popitam: Towards new heuristic strategies to improve protein identification from tandem mass spectrometry dataPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2003Patricia Hernandez Abstract In recent years, proteomics research has gained importance due to increasingly powerful techniques in protein purification, mass spectrometry and identification, and due to the development of extensive protein and DNA databases from various organisms. Nevertheless, current identification methods from spectrometric data have difficulties in handling modifications or mutations in the source peptide. Moreover, they have low performance when run on large databases (such as genomic databases), or with low quality data, for example due to bad calibration or low fragmentation of the source peptide. We present a new algorithm dedicated to automated protein identification from tandem mass spectrometry (MS/MS) data by searching a peptide sequence database. Our identification approach shows promising properties for solving the specific difficulties enumerated above. It consists of matching theoretical peptide sequences issued from a database with a structured representation of the source MS/MS spectrum. The representation is similar to the spectrum graphs commonly used by de novo sequencing software. The identification process involves the parsing of the graph in order to emphazise relevant sections for each theoretical sequence, and leads to a list of peptides ranked by a correlation score. The parsing of the graph, which can be a highly combinatorial task, is performed by a bio-inspired algorithm called Ant Colony Optimization algorithm. [source] Metal-based antitumor, cytotoxic and antimicrobial activity: pharmacological evaluation of Knoevenagel condensate ,-diketone Schiff base thiosemicarbazone Cu(II) and Zn(II) complexesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 7 2009N. Raman Abstract Knoevenagel condensate Schiff base ligands [L = 3-cinnamalideneacetylacetone-thiosemicarbazone (CAT)/3-cinnama- lideneacetylacetoneethylthiosemicarbazone (CAET)/3-cinnamalideneacetylacetonephenylthiosemicarbazone (CAPT)] and their copper/zinc complexes were synthesized. They were characterized by analytical and spectral techniques. From these data it was found that the ligands adopt square-planar geometry on metalation with Cu2+ and Zn2+. To evaluate the antitumor and cytotoxic activity of the synthesized complexes in mice and human cancer cell lines, the antitumor activity of the complexes was evaluated against an Ehrlich ascites carcinoma (EAC) tumor model. The activity was assessed using survival time and short-term in vitro cytotoxic activity. Oral administration of complexes (100 mg/kg) increased the survival time. The cytotoxic activity of complexes was evaluated using human breast cancer (MDA-MB-231), colon cancer (HCT-116) and nonsmall lung cancer (NCI-H-23) cell lines. Both the complexes possessed significant antitumor and cytotoxic activity on EAC and human cancer cell lines. The in vitro antimicrobial screening effect of the investigated compounds was also tested against the various organisms by well diffusion method. Copyright © 2009 John Wiley & Sons, Ltd. [source] An ancient control of epithelial barrier formation and wound healingBIOESSAYS, Issue 10 2005Bernard Moussian Animal epithelia are lined with apical surface matrices, which protect against pathogens, dehydration and physical damage of the underlying cells. The proteins and polysaccharides that comprise these protective barriers vary greatly within the animal kingdom and have evolved in response to the biological needs of various organisms. Yet the genetic control of barrier formation and its regeneration upon wounding appears conserved between vertebrates and insects that are evolutionary more than several hundred millions of years apart.1,2 A key role is carried out by Grainy head, a phylogenetically conserved transcription factor expressed in epidermal cells in nematodes, flies, frogs, mice and humans. BioEssays 27:987,990, 2005. © 2005 Wiley Periodicals, Inc. [source] Increasingly complex: New players enter the Wnt signaling networkBIOESSAYS, Issue 10 2002Petra Pandur Wnt proteins can activate different intracellular signaling cascades in various organisms by interacting with receptors of the Frizzled family. The first identified Wnt signaling pathway, the Wnt/,-catenin pathway, has been studied in much detail and is highly conserved among species. As to non-canonical Wnt pathways, the current situation is more nebulous partly because the intracellular mediators of this pathway are not yet fully understood and, in some cases, even identified. However, there are increasing data that prove the existence of non-canonical Wnt signaling and demonstrate its involvement in different developmental processes. In vertebrates, Wnt-11 and Wnt-5A can activate the Wnt/JNK pathway, which resembles the planar cell polarity pathway in Drosophila. The Wnt/Ca2+ -pathway has only been described in Xenopus and zebrafish so far and it is unclear whether it also exists in other organisms. Two recent papers provide us with new insight into non-canonical Wnt signaling by (1) presenting a new intracellular mediator of non-canonical signaling in Xenopus1 and (2) implicating the existence of an additional non-canonical Wnt signaling pathway in flies.2 BioEssays 24:881,884, 2002. © 2002 Wiley Periodicals, Inc. [source] Structure of Ynk1 from the yeast Saccharomyces cerevisiaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2008Huabing Wang Nucleoside diphosphate kinase (NDPK) catalyzes the transfer of the ,-phosphate from nucleoside triphosphates to nucleoside diphosphates. In addition to biochemical studies, a number of crystal structures of NDPK from various organisms, including both native proteins and complexes with nucleotides or nucleotide analogues, have been determined. Here, the crystal structure of Ynk1, an NDPK from the yeast Saccharomyces cerevisiae, has been solved at 3.1,Å resolution. Structural analysis strongly supports the oligomerization state of this protein being hexameric rather than tetrameric. [source] The subdural space of the spine: A lymphatic sink?CLINICAL ANATOMY, Issue 7 2010Myodil's last message Abstract Following the radiological study of a large number of myelograms, starting over 50 years ago when the only clinical contrast medium available to show the contents of the spinal canal was an iodized oil, the author has collected a number of examples where the oil was inadvertently injected into the subdural area, rather than the intended subarachnoid space. By taking follow-up films at various intervals following the inadvertent injection, it has been possible to study the extent to which the subdural space could become visualized from a lumbar injection, the contrast medium sometimes passing to the top of the cervical region and the lower part of the sacrum. Also, the contrast passed outward along the peri-neural lymphatic sheaths or spaces of the issuing spinal nerves, where it might remain for months, and under the influence of gravity it could extend for a considerable way. It also passed into abdominal and thoracic lymph vessels and nodes. Considering the morphology, predictability, and ease with which the demonstrated subdural space fills, the author concludes that the subdural region is a true and functionally significant "space," and an important conduit or functional part of the body's lymphatic system. He also considers that it has implications for the spread or dissemination of various organisms, substances or pathological conditions, as well as being part of the normal conduit for reabsorption of CSF with implications for hydrocephalus, and with potential for misplacement of spinal anaesthetic agents. Clin. Anat. 23:829,839, 2010. © 2010 Wiley-Liss, Inc. [source] | |||||||||||||