A common theme in interaction of bacterial immunoglobulin-binding proteins with immunoglobulins illustrated in the equine system

The M protein of Streptococcus equi subsp. equi known as fibrinogen-binding protein (FgBP) is a cell wall-associated protein with antiphagocytic activity that binds IgG. Recombinant versions of the seven equine IgG subclasses were used to investigate the subclass specificity of FgBP. FgBP bound predominantly to equine IgG4 and IgG7, with little or no binding to the other subclasses. Competitive binding experiments revealed that FgBP could inhibit the binding of staphylococcal protein A and streptococcal protein G to both IgG4 and IgG7, implicating the Fc interdomain region in binding to FgBP. To identify which of the two IgG Fc domains contributed to the interaction with FgBP, we tested two human IgG1/IgA1 domain swap mutants and found that both domains are required for full binding, with the CH3 domain playing a critical role. The binding site for FgBP was further localized using recombinant equine IgG7 antibodies with single or double point mutations to residues lying at the CH2-CH3 interface. We found that interaction of FgBP with equine IgG4 and IgG7 was able to disrupt C1q binding and antibody-mediated activation of the classical complement pathway, demonstrating an effective means by which S. equi may evade the immune response. The mode of interaction of FgBP with IgG fits a common theme for bacterial Ig-binding proteins. Remarkably, for those interactions studied in detail, it emerges that all the Ig-binding proteins target the CH2-CH3 domain interface, regardless of specificity for IgG or IgA, streptococcal or staphylococcal origin, or host species (equine or human)

Pardaxin Stimulation of Phospholipases A 2 and Their Involvement in Exocytosis in PC-12 Cells

ABSTRACT Pardaxin (PX) is a voltage-dependent ionophore that stimulates catecholamine exocytosis from PC-12 pheochromocytoma cells both in the presence and absence of extracellular calcium. Using a battery of phospholipase A 2 inhibitors we show that PX stimulation of phospholipase A 2 (PLA 2 ) enzymes is coupled with induction of exocytosis. We investigated the relationship between PX-induced PLA 2 activity and neurotransmitter release by measuring the levels of arachidonic acid (AA), prostaglandin E 2 (PGE 2 ), and dopamine release. In the presence of extracellular calcium, the cytosolic PLA 2 inhibitor arachidonyl trifluoromethyl ketone (AACOCF 3 ) inhibited by 100, 70, and 73%, respectively, the release of AA, PGE 2 , and dopamine induced by PX. The mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor 2Ј-amino-3Ј-methoxyflavone (PD98059) reduced by 100 and 82%, respectively, the release of AA and PGE 2 induced by PX. In the absence of extracellular calcium, the calcium-independent PLA 2 (iPLA 2 ) inhibitors methyl arachidonyl fluorophosphonate, AACOCF 3 , and bromoenol lactone (BEL) inhibited by 80 to 90% PX stimulation of AA release, by 65 to 85% PX stimulation of PGE 2 release, and by 80 to 90% PX-induced dopamine release. Using vesicle fusion-based enzyme-linked immunosorbent assay we found similar levels of inhibition of PX-induced exocytosis by these inhibitors. Also, PX induced the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor complexes, an effect that was augmented by N-methylmaleimide. This complex formation was completely inhibited by BEL. Botulinum toxins type C1 and F significantly inhibited the release of AA, PGE 2 , and dopamine induced by PX. Our data suggest that PX stimulates exocytosis by activating cystolic PLA 2 and iPLA 2 , leading to the generation of AA and eicosanoids, which, in turn, stimulate vesicle competence for fusion and neurotransmitter release. Hormones and neurotransmitters are usually released from cells by exocytosis, when a rise in cytosolic calcium triggers fusion of the secretory vesicle membrane with the plasma membrane SNAREs are targets for the botulinum and tetanus toxins Aside from toxins that inhibit neurotransmitter release, there are others that cause a massive release of neurotrans-E.B.-S. and S.A.-R. contributed equally to this work

A rapid staining technique for the detection of the initiation of germination of bacterial spores

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75645/1/j.1472-765x.2002.01047.x.pd

Isolation and Characterization of a Mn(II)-Oxidizing Bacillus Strain from the Demosponge Suberites domuncula

In this study we demonstrate that the demosponge Suberites domuncula harbors a Mn(II)-oxidizing bacterium, a Bacillus strain, termed BAC-SubDo-03. Our studies showed that Mn(II) stimulates bacterial growth and induces sporulation. Moreover, we show that these bacteria immobilize manganese on their cell surface. Comparison of the 16S rDNA sequence allowed the grouping of BAC-SubDo-03 to the Mn-precipitating bacteria. Analysis of the spore cell wall revealed that it contains an Mn(II)-oxidizing enzyme. Co-incubation studies of BAC-SubDo-03 with 100 μM MnCl2 and >1 μM of CuCl2 showed an increase in their Mn(II)-oxidizing capacity. In order to prove that a multicopper oxidase-like enzyme(s) (MCO) exists in the cell wall of the S. domuncula-associated BAC-SubDo-03 Bacillus strain, the gene encoding this enzyme was cloned (mnxG-SubDo-03). Sequence alignment of the deduced MCO protein (MnxG-SubDo-03) revealed that the sponge bacterium clusters together with known Mn(II)-oxidizing bacteria. The expression of the mnxG-SubDo-03 gene is under strong control of extracellular Mn(II). Based on these findings, we assume that BAC-SubDo-03 might serve as a Mn reserve in the sponge providing the animal with the capacity to detoxify Mn in the environment. Applying the in vitro primmorph cell culture system we could demonstrate that sponge cells, that were co-incubated with BAC-SubDo-03 in the presence of Mn(II), show an increased proliferation potential

Carl Boschwitz - Hermann Leubsdorf Collection 1731-1959

The first series, Carl Boschwitz papers, consists primarily of correspondenc,e mostly in connection with his work with the Prisoners of War Relief Committee (Kriegsgefangenen Fürsorge, later the Welfare Committee for Prisoners of War), and the Kolonialkriegerdank (Colonial soldiers' gratitude committee) on behalf of German and Austrian prisoners of war during and after World War I, 1914-1921.This includes correspondence with the German and Austrian embassies, the German Red Cross, and individual prisoners of war. Later correspondence is limited but includes a letter from German Chancellor Franz von Papen in 1932, in which he assures Boschwitz that there is no place for National Socialism in the German government. In addition to correspondence, Boschwitz's papers include a marriage certificate and a family tree.The documents of the Leubsdorf family and the van Geldern families include wills, contracts, guild papers, and correspondence, including correspondence of Betty Heine (born Peira van Geldern), the mother of Heinrich Heine. Other family members prominently represented in the collection include Abraham Samuel, Isaac Bürger, David Pinchas Bock, Samson Heine (Heinrich Heine's father), and Isaac Leubsdorf. Many of these documents appear to have been used for genealogical research. Several family trees, some of which appear to have been drafted in the nineteenth century, and a genealogical manuscript narrative attest to this research. In addition, there is an eighteenth century prayer book which had belonged to Sender Offebach; how it entered Leubsdorf possession is unclear. Some correspondence from the twentieth century documents contemporary family affairs and the genealogical research efforts.Carl Boschwitz (1877-1937) was a businessman who emigrated to the United States in 1914.Hermann Leubsdorf was the great-great grandson of Brunella van Geldern, sister of Betty van Geldern, Heinrich Heine's mother.An earlier inventory islocated in folder 1.See also: 1) Memoir by (Charlotte) Engel Levinson: 'A Patchwork of memories' (ME 1229); 2) 'Levison, Wilhelm: Die Siegburger Familie Levison und verwandte Familien'; 3) William and (Charlotte) Engel Levison Collection (AR 25001); 4) Wilhelm Levison Collection (AR 3906)digitize