Characterization of exopolymeric substances (EPS) produced byAeromonas hydrophilaunder reducing conditions

SummaryWe report the characterization of a monoclonal antibody (MAb) PM6/13 which recognises glycoprotein IIIa (GPIIIa) on platelet membranes and in functional studies inhibits platelet aggregation induced by all agonists examined. In platelet-rich plasma, inhibition of aggregation induced by ADP or low concentrations of collagen was accompanied by inhibition of 5-hydroxytryptamine secretion. EC50 values were 10 and 9 [H9262]g/ml antibody against ADP and collagen induced responses respectively. In washed platelets treated with the cyclooxygenase inhibitor, indomethacin, PM6/13 inhibited platelet aggregation induced by thrombin (0.2 U/ml), collagen (10 [H9262]g/ml) and U46619 (3 [H9262]M) with EC50 = 4, 8 and 4 [H9262]g/ml respectively, without affecting [14C]5-hydroxytryptamine secretion or [3H]arachidonate release in appropriately labelled cells. Studies in Fura 2-labelled platelets revealed that elevation of intracellular calcium by ADP, thrombin or U46619 was unaffected by PM6/13 suggesting that the epitope recognised by the antibody did not influence Ca2+ regulation. In agreement with the results from the platelet aggregation studies, PM6/13 was found to potently inhibit binding of 125I-fibrinogen to ADP activated platelets. Binding of this ligand was also inhibited by two other MAbs tested, namely SZ-21 (also to GPIIIa) and PM6/248 (to the GPIIb-IIIa complex). However when tested against binding of 125I-fibronectin to thrombin stimulated platelets, PM6/13 was ineffective in contrast with SZ-21 and PM6/248, that were both potent inhibitors. This suggested that the epitopes recognised by PM6/13 and SZ-21 on GPIIIa were distinct. Studies employing proteolytic dissection of 125I-labelled GPIIIa by trypsin followed by immunoprecipitation with PM6/13 and analysis by SDS-PAGE, revealed the presence of four fragments at 70, 55, 30 and 28 kDa. PM6/13 did not recognize any protein bands on Western blots performed under reducing conditions. However Western blotting analysis with PM6/13 under non-reducing conditions revealed strong detection of the parent GP IIIa molecule, of trypsin treated samples revealed recognition of an 80 kDa fragment at 1 min, faint recognition of a 60 kDa fragment at 60 min and no recognition of any product at 18 h treatment. Under similar conditions, SZ-21 recognized fragments at 80, 75 and 55 kDa with the 55kDa species persisting even after 18 h trypsin treatment. These studies confirm the epitopes recognised by PM6/13 and SZ-21 to be distinct and that PM6/13 represents a useful tool to differentiate the characteristics of fibrinogen and fibronectin binding to the GPIIb-IIIa complex on activated platelets.

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Qualitative characterization of the protein fraction of exopolymeric substances (EPS) extracted with EDTA from sludge

Bioresource Technology ◽

10.1016/j.biortech.2011.11.033 ◽

2012 ◽

Vol 104 ◽

pp. 486-496 ◽

Cited By ~ 33

Author(s):

Isabelle Bourven ◽

Guy Costa ◽

Gilles Guibaud

Keyword(s):

Protein Fraction ◽

Exopolymeric Substances

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Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

Journal of Materials Research ◽

10.1557/jmr.2003.0154 ◽

2003 ◽

Vol 18 (5) ◽

pp. 1123-1130 ◽

Cited By ~ 6

Author(s):

V. Oliveira ◽

R. Vilar

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Laser Pulses ◽

Formation Mechanisms ◽

X Ray ◽

Reducing Conditions ◽

Transmission Electron ◽

Column Formation ◽

Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

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A- and B-site doping effect on physicochemical properties of Sr2−xBaxMMoO6 (M = Mg, Mn, Fe) double perovskites — candidate anode materials for SOFCs

Functional Materials Letters ◽

10.1142/s1793604716410022 ◽

2016 ◽

Vol 09 (04) ◽

pp. 1641002 ◽

Cited By ~ 2

Author(s):

Kun Zheng ◽

Konrad Świerczek

Keyword(s):

Physicochemical Properties ◽

Solid Oxide Fuel Cells ◽

Anode Materials ◽

Full Range ◽

Solid Oxide ◽

Double Perovskites ◽

Reducing Conditions ◽

Redox Stability ◽

Very High

In this work, we evaluate the physicochemical properties of Sr[Formula: see text]BaxMMoO6 (M [Formula: see text] Mg, Mn, Fe) double perovskites as alternative anode materials for solid oxide fuel cells, for which the effect of substitution of strontium by barium in a full range of compositions is studied. The crystal structure, microstructure, characterization of transport properties (electrical conductivity, Seebeck coefficient) and oxygen content as a function of temperature, as well as chemical stability in oxidizing and reducing conditions are discussed. Fe- and Mo-containing Sr[Formula: see text]BaxFeMoO6 oxides show very high total conductivities with values of 100–1000 S[Formula: see text][Formula: see text]cm[Formula: see text], while Sr[Formula: see text]BaxMgMoO6 present good redox stability.

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Molecular Characterization of Biofilm Formation and Attachment of Salmonella enterica Serovar Typhimurium DT104 on Food Contact Surfaces

Journal of Food Protection ◽

10.4315/0362-028x-72.9.1841 ◽

2009 ◽

Vol 72 (9) ◽

pp. 1841-1847 ◽

Cited By ~ 37

Author(s):

SHIN-HEE KIM ◽

CHENG-I WEI

Keyword(s):

Outer Membrane ◽

Biofilm Formation ◽

Rna Binding ◽

Salmonella Enterica Serovar Typhimurium ◽

Membrane Expression ◽

Exopolymeric Substances ◽

Food Contact Surfaces ◽

Serovar Typhimurium ◽

Contact Surfaces

The molecular mechanism of biofilm formation by Salmonella Typhimuriun DT104 was characterized for a better understanding of its attachment and colonization in food processing environments. A library of random mutagenized clones was screened for phenotypic analyses of their ability to form biofilm, pellicle, curli, and cellulose. The genes identified were involved in lipopolysaccharide synthesis, assembly of flagella, regulation of rRNA biosynthesis, and outer membrane transportation and signaling. The insertion of transposon in flgK, rfbA, nusB, and pnp genes resulted in decreased biofilm formation. Alterations of flagellar and lipopolysaccharide production were confirmed in the flgK mutant and rfbA mutant, respectively. Biofilm formation by these four mutants in meat and poultry broths and their attachment on surfaces of stainless steel and glass were significantly reduced compared with those of the wild-type strain (P < 0.05). On the contrary, the mutation of STM4263 and yjcC genes in Salmonella Typhimuriun DT104 resulted in increased biofilm formation and attachment of the species in tested broths and on contact surfaces. Our findings suggest that many factors, such as production of exopolymeric substances and their efficient transportation through outer membrane, expression of flagella, and regulation of exoribonucleases and RNA-binding protein, could be involved in biofilm formation and attachment of Salmonella Typhimurium DT104 on contact surfaces.

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The purification, characterization, serological activity and hepatotoxic properties of two cationic glycoproteins (α1and ω1) fromSchistosoma mansonieggs

Parasitology ◽

10.1017/s0031182000059503 ◽

1991 ◽

Vol 103 (2) ◽

pp. 225-236 ◽

Cited By ~ 65

Author(s):

D. W. Dunne ◽

F. M. Jones ◽

M. J. Doenhoff

Keyword(s):

Molecular Weight ◽

T Cell ◽

Passive Transfer ◽

Human Infection ◽

Purification And Characterization ◽

Reducing Conditions ◽

Hepatocyte Damage ◽

Serological Activity

T cell-deprived mice acutely infected withS. mansonisuffer microvesicular hepatocyte damage which is not seen in infected, immunological intact animals. A cationic fraction (CEF6) of the PBS-soluble portion ofS. mansonieggs (SEA) induces antibodies which, on passive transfer, prevent hepatocyte damage. CEF6 contains 2 antigens, ω1and α1, and has also been shown to be a useful serodiagnostic reagent. This paper describes the purification and characterization of the 2 antigens present in CEF6. ω1is a monomeric glycoprotein with a pI > 9·0 and a molecular weight of 31 kDa. α1consists of two immunologically cross-reactive dimers, 41 and 36 kDa in non-reducing conditions, each of which consists of one unique and one common glycoprotein subcomponent. In ELISA with mouse and human infection sera ω1is shown to beS. mansonispecific and is better able to distinguishS. mansoniinfections from other schistosome infections than are unfractionated SEA, CEF6 or α1. Passive transfer of monospecific anti-ω1sera intoS. mansoniinfected, T cell-deprived mice completely prevented the occurrence of microvesicular hepatocyte damage in these animals. Monospecific anti-α1serum had no hepatoprotective capacity.

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Effect of Oxidation Rate and Fe(II) State on Microbial Nitrate-Dependent Fe(III) Mineral Formation

Applied and Environmental Microbiology ◽

10.1128/aem.71.11.7172-7177.2005 ◽

2005 ◽

Vol 71 (11) ◽

pp. 7172-7177 ◽

Cited By ~ 50

Author(s):

John M. Senko ◽

Thomas A. Dewers ◽

Lee R. Krumholz

Keyword(s):

Oxidation Rate ◽

Sequence Similarity ◽

Klebsiella Oxytoca ◽

Xrd Analysis ◽

X Ray Diffraction ◽

16S Rrna Sequence ◽

X Ray ◽

Oxidation Rates ◽

Reducing Conditions

ABSTRACT A nitrate-dependent Fe(II)-oxidizing bacterium was isolated and used to evaluate whether Fe(II) chemical form or oxidation rate had an effect on the mineralogy of biogenic Fe(III) (hydr)oxides resulting from nitrate-dependent Fe(II) oxidation. The isolate (designated FW33AN) had 99% 16S rRNA sequence similarity to Klebsiella oxytoca. FW33AN produced Fe(III) (hydr)oxides by oxidation of soluble Fe(II) [Fe(II)sol] or FeS under nitrate-reducing conditions. Based on X-ray diffraction (XRD) analysis, Fe(III) (hydr)oxide produced by oxidation of FeS was shown to be amorphous, while oxidation of Fe(II)sol yielded goethite. The rate of Fe(II) oxidation was then manipulated by incubating various cell concentrations of FW33AN with Fe(II)sol and nitrate. Characterization of products revealed that as Fe(II) oxidation rates slowed, a stronger goethite signal was observed by XRD and a larger proportion of Fe(III) was in the crystalline fraction. Since the mineralogy of Fe(III) (hydr)oxides may control the extent of subsequent Fe(III) reduction, the variables we identify here may have an effect on the biogeochemical cycling of Fe in anoxic ecosystems.

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Purification, Characterization of an Entomopathogenic Fungal Lectin from Purpureocillium Lilacinum, and its Involvement in Pathogenesis Leading to Mycotic Keratitis

10.21203/rs.3.rs-876400/v1 ◽

2021 ◽

Author(s):

Narasimhappagari Jagadeesh ◽

Supreeth Kulkarni ◽

Vishwanath B Chachadi ◽

Sanhita Roy ◽

Shashikala Inamdar

Keyword(s):

Proinflammatory Response ◽

Corneal Epithelial ◽

Purpureocillium Lilacinum ◽

Ammonium Sulphate Precipitation ◽

Reducing Conditions ◽

Sds Page ◽

Fungal Lectin ◽

Human Corneal Epithelial Cells ◽

Ph Range

Abstract A lectin PCL, from Purpureocillium lilacinum a saprophytic, filamentous fungus was purified from the crude extract of the mycelia using 70% ammonium sulphate precipitation followed by affinity chromatography on mucin-Sepharose 4 B column. PCL is a monomer with an apparent molecular mass of 18.5 kDa as revealed by SDS-PAGE under both reducing and non reducing conditions. PCL is a blood group non specific lectin and has highest affinity towards Chitin, Mucin, asialo mucin, Fetuin with a MIC of 0.15µg/mL and also recognizes L-fucose, galactose, lactose, N-acetly galactosamine, Hyaluronic acid. PCL is stable up to 60 ºC and within the pH range 4–8. To understand its role in pathogenesis, effect of PCL was evaluated on Human Corneal Epithelial Cells (HCECs). PCL showed strong glycan mediated binding to HCECsand PCL showed proinflammatory response at lower concentrations by stimulating secretion of IL-6, 8. In contrast PCL at higher concentrations revealed opposite effect of HCECs growth inhibition. All these results collectively support the involvement of PCL in mediating host pathogen interactions possibly leading to pathogenesis. In addition, considering the entomopathogenic effect of Purpureocillium lilacinum, PCL may be attributed for this beneficiary effect, which needs to be explored.

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Identification of Platelet Antigens by Immunoprecipitation of Unlabelled Platelet Glycoproteins

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647338 ◽

1990 ◽

Vol 64 (03) ◽

pp. 469-472 ◽

Cited By ~ 1

Author(s):

Werner Stenziger ◽

Beate Kehrel ◽

Jürgen van de Loo

Keyword(s):

Monoclonal Antibodies ◽

Silver Staining ◽

Protein G ◽

Time Saving ◽

Radioactive Substances ◽

Reducing Conditions ◽

Fast Flow ◽

Murine Monoclonal Antibodies ◽

Sensitive Method

SummaryA time-saving and sensitive method for the identification of antigens on unlabelled platelet glycoproteins (GP) based on immunoprecipitation has been developed. Platelet solubilisates were incubated with antibodies to form GP-antibody complexes that were precipitated with Protein G Sepharose 4 Fast Flow (PGS). Pcs-bound material was eluted, separated by SDSPAGE under reducing conditions and visualized by silver staining. The method was designed as an alternative to radioimmunoprecipitation for laboratories not equipped to work with radioactive substances. It is proposed as a complementary procedure for the characterization of platelet GP antigens by murine monoclonal antibodies and human alloantibodies.

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Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments

Scientific Reports ◽

10.1038/s41598-019-53272-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Julien Alleon ◽

David T. Flannery ◽

Nicola Ferralis ◽

Kenneth H. Williford ◽

Yong Zhang ◽

...

Keyword(s):

Organic Matter ◽

Mineralogical Composition ◽

Molecular Characteristics ◽

Reducing Conditions ◽

Mineral Associations ◽

Alteration Processes ◽

Molecular Information ◽

Organic Precursors ◽

Pool Formation

Abstract Hydrothermal and metamorphic processes could have abiotically produced organo-mineral associations displaying morphological and isotopic characteristics similar to those of fossilized microorganisms in ancient rocks, thereby leaving false-positive evidence for early life in the geological record. Recent studies revealed that geologically-induced alteration processes do not always completely obliterate all molecular information about the original organic precursors of ancient microfossils. Here, we report the molecular, geochemical, and mineralogical composition of organo-mineral associations in a chert sample from the ca. 3.47 billion-year-old (Ga) Mount Ada Basalt, in the Pilbara Craton, Western Australia. Our observations indicate that the molecular characteristics of carbonaceous matter are consistent with hydrothermally altered biological organics, although significantly distinct from that of organic microfossils discovered in a chert sample from the ca. 3.43 Ga Strelley Pool Formation in the same area. Alternatively, the presence of native metal alloys in the chert, previously believed to be unstable in such hydrothermally influenced environments, indicates strongly reducing conditions that were favorable for the abiotic formation of organic matter. Drawing definitive conclusions about the origin of most Paleoarchean organo-mineral associations therefore requires further characterization of a range of natural samples together with experimental simulations to constrain the molecular composition and geological fate of hydrothermally-generated condensed organics.

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