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Selected AbstractsThe heterogeneous distribution of functional synaptic connections in rat hippocampal dissociated neuron culturesELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 6 2009Suguru N. Kudoh Abstract The dynamics of functional synaptic connections are critical for information processing systems in the brain, such as perception and learning. Using rat hippocampal cells cultured on multielectrode arrays, we investigated the spatiotemporal pattern of spontaneous action potentials. The neurons developed connections and a characteristic high-frequency bursting (HFB) activity was observed transiently. After the period of HFB activity, the distribution of spontaneous activity changed drastically with the appearance of neurons with frequent electrical activity and neurons with little activity in the network. The functional connections of all the combinations of recorded spike trains were estimated and depicted simultaneously in a Connection Map. This map revealed that each culture contained hublike neurons with many functional connections, suggesting that the cultures of dissociated rat hippocampal neurons on multielectrode arrays formed heterogeneous networks of functional connections. In addition, the functional connections were drastically reorganized after the induction of synaptic potentiation, and novel hub neurons emerged. These results indicate that spontaneous activity is enough to construct dynamic assemblies of neurons connected to each other by functional synaptic connections, and that synaptic potentiation can induce reorganization of such assemblies of neurons. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(6): 41,49, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10063 [source] Crystal structures of isomaltase from Saccharomyces cerevisiae and in complex with its competitive inhibitor maltoseFEBS JOURNAL, Issue 20 2010Keizo Yamamoto The structures of isomaltase from Saccharomyces cerevisiae and in complex with maltose were determined at resolutions of 1.30 and 1.60 Å, respectively. Isomaltase contains three domains, namely, A, B, and C. Domain A consists of the (,/,)8 -barrel common to glycoside hydrolase family 13. However, the folding of domain C is rarely seen in other glycoside hydrolase family 13 enzymes. An electron density corresponding to a nonreducing end glucose residue was observed in the active site of isomaltase in complex with maltose; however, only incomplete density was observed for the reducing end. The active site pocket contains two water chains. One water chain is a water path from the bottom of the pocket to the surface of the protein, and may act as a water drain during substrate binding. The other water chain, which consists of six water molecules, is located near the catalytic residues Glu277 and Asp352. These water molecules may act as a reservoir that provides water for subsequent hydrolytic events. The best substrate for oligo-1,6-glucosidase is isomaltotriose; other, longer-chain, oligosaccharides are also good substrates. However, isomaltase shows the highest activity towards isomaltose and very little activity towards longer oligosaccharides. This is because the entrance to the active site pocket of isomaltose is severely narrowed by Tyr158, His280, and loop 310,315, and because the isomaltase pocket is shallower than that of other oligo-1,6-glucosidases. These features of the isomaltase active site pocket prevent isomalto-oligosaccharides from binding to the active site effectively. [source] Human salivary aggregation in Streptococcus intermedius type g strains: relationship with IgAFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2004Taihei Yamaguchi Abstract Bacterial aggregation is an important step in elimination from the human body to protect against infection. Streptococcus intermedius K1K aggregates in human saliva. In this study, the salivary agglutinin was identified. The aggregation level was very strong in sonic-treated saliva and 1-,m filtrate. Preincubation of human saliva with anti-human , chain serum or anti-human whole saliva serum completely inhibited aggregation, but preincubation with anti-human , chain serum or anti-Fc fragment of human IgG serum had no effect. Agglutinin of human saliva that could aggregate the strain K1K was purified using DEAE,Sepharose CL-6B, Phenyl,Sepharose CL-4B and Sephacryl S200HR gel filtration. Purified salivary agglutinin was characterized with electrophoresis and immunological techniques, indicating that purified material was IgA. Bacterial aggregation was dependent on the presence of calcium. Saliva filtrate specimens from eight healthy men and eight women showed different aggregation activities. Three men and one woman had little activity. These data show that the present bacterial aggregation was an immunoreaction between IgA in saliva and the bacteria dependent on the levels of calcium. In addition, the IgA in human saliva related with possible calcium-dependent antigen(s) on the surface of strain K1K. [source] Specificities of proteases for use in leather manufactureJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2006Farhad Foroughi Abstract Proteases are used in leather manufacture in the processes of soaking, unhairing and bating of hides and skins. However proteases can be relatively non-specific in their usage, and for improved efficacy of enzyme biocatalysis within the industry, an analysis of specific activities of enzymes towards skin proteins was undertaken. Most commercial proteases for soaking showed substantial activity against the substrates elastin,Congo Red and Azocoll but little or no activity against keratin,azure and hide powder black. Enzymes used for unhairing in conjunction with 30% of the usual concentration of sulfide to effect chemical unhairing showed moderate activity against all substrates tested (selected as representative of skin proteins), while proteases used in bating showed activity against Azocoll and elastin,Congo Red but had no keratinase activity and little activity against hide powder black. Bating proteases and soaking proteases displayed similar activities at pH 8. Microbes isolated in the screening of organisms from putrefied skins included one fungal and two bacterial isolates whose extracellular enzymes had efficient unhairing activity without the addition of sulfide. Enzyme activities for these proteases included high activity measured against Azocoll with little or no activity against elastin,Congo Red, keratin,azure and hide powder black. Neither elastase nor keratinase activities were determined as being essential for unhairing. Copyright © 2005 Society of Chemical Industry [source] Is the superior belly of the lateral pterygoid primarily a stabilizer?JOURNAL OF ORAL REHABILITATION, Issue 6 2001An EMG study The aim of the present study was to compare the activity levels within the two bellies of the lateral pterygoid muscle between different jaw positions to test the hypothesis that the upper head is primarily a stabilizer. Electromyographic (EMG) recordings, using monopolar concentric needle electrodes, were made from 14 healthy subjects during mandibular rest position (RP), clenching in intercuspal position and jaw opening, first about 10 mm and then about 25 mm. Both bellies had very little activity during RP. The activity level of the superior belly was high during clenching and large opening (LO) with a dip during low opening degree. This pattern differed from that of the inferior belly where the activity was relatively low during clenching and then gradually increased to its highest level during LO. The results support that the lower belly is primarily a jaw opener while the superior belly acts as a stabilizer keeping the disc and condyle in a functionally stable position during clenching and jaw movements. [source] Bactericidal effect of dentin primer containing antibacterial monomer methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human carious dentinJOURNAL OF ORAL REHABILITATION, Issue 4 2001S. Imazato The aim of this study was to investigate the bactericidal effect of a dentin primer incorporating the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human dentinal carious lesions. To evaluate the antibacterial activity of MDPB against anaerobes, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against obligate anaerobes and facultative anaerobic strains of lactobacilli were determined. Bacteria were recovered from carious dentin samples obtained from the teeth of patients, and the bactericidal activities of the experimental primer containing 5% MDPB and three commercially available primers were compared by counting the number of viable cells after contact with diluted solutions of each primer for 30 s. MDPB showed strong antibacterial activity against anaerobes, the MIC and MBC values ranging from 3·9 to 31·3 ,g mL,1 and 15·6,125 ,g mL,1, respectively. Experimental primer containing MDPB was the most bactericidal among the materials tested (ANOVA, Fisher's PLSD test, P < 0·05) and was able to kill the bacteria completely even when diluted 40 times, while the three commercial products exhibited little activity at 40 times dilution. These results indicate that incorporation of MDPB into dentin primer could be beneficial for eliminating the residual bacteria in cavities. [source] Protective, Curative and Eradicant Activity of the Strobilurin Fungicide Azoxystrobin against Cercospora beticola and Erysiphe betaeJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2003T. Anesiadis Abstract The protective, curative and eradicant activity of the strobilurin fungicide azoxystrobin against Cercospora beticola and Erysiphe betae on sugar beet was determined under growth chamber conditions. Difenoconazole and chlorothalonil were used as standard fungicides against C. beticola, while chlorothalonil was replaced by sulphur against E. betae. Fungicides were applied before (protective treatments) and after (curative treatments) inoculation at 24, 48 and 96 h intervals, respectively. An additional spray treatment was applied after the appearance of the symptoms to evaluate the eradicant activity of the fungicides tested. Applications of azoxystrobin at 16 ,/ml provided 89,94% and 95,97% disease control against C. beticola and E. betae, respectively. Curative treatments of azoxystrobin either at 8 or 16 ,g/ml provided control of Cercospora leaf-spot higher than 90% only when it was applied 24 h after inoculation of the plants. Comparatively, chlorothalonil (100 ,g/ml) provided satisfactory control of C. beticola when applied in protective treatments (83,87% disease control) but showed little activity when applied after the inoculation of the seedlings (45,76% disease control). High control efficacy against E. betae was also obtained by protective applications of sulphur (600 ,g/ml) but the fungicide failed to provide satisfactory disease control, particularly when applied for 48 or 96 h after inoculation of seedlings. Difenoconazole (8 ,g/ml) gave excellent protective and curative activity against both pathogens. Eradicative treatments with azoxystrobin provided high antisporulant activity of 94,96% and 85,93% against C. beticola and E. betae, respectively. Similarly, high antisporulant activity was also provided by difenoconazole, while postsymptom applications of chlorothalonil and sulphur provided significantly lower antisporulant activity against C. beticola and E. betae, respectively. Such results encourage the evaluation of azoxystrobin under field conditions to determine optimal treatment schedules and to select possibly partner fungicides for use in mixtures. [source] Phytochemistry and preliminary biological evaluation of Cyathostemma argenteum, a malaysian plant used traditionally for the treatment of breast cancerPHYTOTHERAPY RESEARCH, Issue 7 2004i Khamis Abstract Bioassay guided fractionation of the roots of Cyathostemma argenteum using the brine shrimp resulted in the isolation of two uncommon ,avanones, 2,5-dihydroxy-7-methoxy,avanone 1 and 2,5-dihydroxy-6,7-dimethoxy,avanone 2 while the stem bark yielded the related compounds 5-hydroxy-7-methoxy,avone 3 and 5-hydroxy-6,7-dimethoxy,avone 4. The alkaloids liriodenine 5 and discretamine 6 as well as benzyl benzoate 7 were isolated from the roots and 6 was also isolated from the stembark. In cytotoxicity tests using four human breast cancer cell lines, 1 and 2 were weakly toxic to MCF-7 cells (IC50 = 19.6 and 19.0 µm, respectively) but showed little activity against MCF-7 cells resistant to doxorubicin or against two oestrogen receptor-de,cient cell lines. Compound 5, but not 6 and 7, was moderately cytotoxic against all four cell lines. These results are discussed in the context of the traditional use of C. argenteum in the treatment of breast cancer. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effect of environmental factors and Sclerotium cepivorum isolate on sclerotial degradation and biological control of white rot by TrichodermaPLANT PATHOLOGY, Issue 3 2004J. P. Clarkson Laboratory assays demonstrated that two isolates of Trichoderma viride and one isolate of Trichoderma pseudokoningii degraded up to 80% of sclerotia of four isolates of Sclerotium cepivorum in a silty clay soil, and also degraded up to 60% of sclerotia in three other soil types. Relationships were defined between the degree of sclerotial degradation by the two T. viride isolates in the silty clay soil and both temperature and soil water potential. Sclerotia were degraded between 10 and 25°C at ,0·00012 MPa, but there was little activity of T. viride at 5°C or at ,4 MPa. Degradation of S. cepivorum sclerotia also occurred in the absence of Trichoderma at soil water potentials approaching saturation. Experiments using onion seedling bioassays showed that the efficacy of Trichoderma isolates for the control of white rot using the same selection of soils and S. cepivorum isolates was variable, but that there was significant disease control overall. The importance of environmental factors and pathogen isolate in relation to effective biological control of white rot is discussed. [source] Crystallization and preliminary X-ray analysis of isomaltase from Saccharomyces cerevisiaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2008Keizo Yamamoto Isomaltase from Saccharomyces cerevisiae is an oligo-1,6-glucosidase that preferentially hydrolyzes isomaltose, with little activity towards isomaltotriose or longer oligosaccharides. An amino-acid sequence analysis of the isomaltase revealed that it belongs to glucoside hydrolase family 13. Recombinant isomaltase was purified and crystallized by the hanging-drop vapour-diffusion method with PEG 3350 as the precipitant. The crystals belonged to space group C2, with unit-cell parameters a = 95.67, b = 115.42, c = 61.77,Å, , = 91.17°. X-ray diffraction data were collected to 1.35,Å resolution from a single crystal on a synchrotron-radiation source. [source] The present role of corticosteroids in uveitisACTA OPHTHALMOLOGICA, Issue 2009M KHAIRALLAH Corticosteroids are the most widely used anti-inflammatory and immunosuppressant drugs in ophthalmology in general, and remain the mainstay of therapy for patients with uveitis. An infectious etiology for intraocular inflammation should be adequately excluded or appropriately covered with anti-infectious therapy before administration of corticosteroid therapy. Topical corticosteroids alone are usually effective in the management of anterior uveitis and have little activity against intermediate or posterior uveitis. Ocular adverse effects of topical steroid therapy mainly include ocular hypertension and cataract. The use of periocular steroid injections (subconjunctival, anterior or posterior subtenon, orbital floor) are important modalities in the management of anterior uveitis refractory to topical treatment and intermediate or posterior uveitis, particularly unilateral cases. Systemic corticosteroids remain the initial drug of choice for most patients with severe bilateral intermediate or posterior uveitis. Therapy is initiated with 1.0 to 2.0 mg/Kg of oral prednisone or prednisolone as a single morning dose, followed by a slow taper. Use of intravenous pulse steroid therapy is an important option in acute, severe, bilateral posterior segment inflammation. In several cases, the level of systemic steroid required to control the inflammation is too high and unacceptable. Immunosuppressive drugs as steroid-sparing agents are indicated is such cases. Intravitreal injection of triamcinolone acetonide and slow-release intraocular devices are therapeutic options that can be used in selected uveitis cases refractory to conventional therapy and biologic agents. [source] | ||||||||||||||||