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Oleg Ya. Shatursky

Bio: Oleg Ya. Shatursky is an academic researcher from University of Oklahoma Health Sciences Center. The author has contributed to research in topics: Lipid bilayer & Membrane. The author has an hindex of 8, co-authored 12 publications receiving 674 citations. Previous affiliations of Oleg Ya. Shatursky include National Academy of Sciences of Ukraine.

Papers
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Journal ArticleDOI
29 Oct 1999-Cell
TL;DR: The insertion of two transmembrane hairpins per toxin monomer and the major change in secondary structure are striking and define a novel paradigm for the mechanism of membrane insertion by a cytolytic toxin.

355 citations

Journal ArticleDOI
TL;DR: The hypothesis that PFO forms a large oligomeric prepore complex on the membrane surface prior to the insertion of its transmembrane beta-sheet is strongly supported.
Abstract: Perfringolysin O (PFO) is a member of the cholesterol-dependent cytolysin (CDC) family of membrane-penetrating toxins. The CDCs form large homooligomers (estimated to be comprised of up to 50 CDC m...

200 citations

Journal ArticleDOI
TL;DR: Recombinant beta-toxin from Clostridium perfringenstype C was found to increase the conductance of bilayer lipid membranes by inducing channel activity, and the hypothesis that the lethal action of beta-Toxin is based on the formation of cation-selective pores in susceptible cells is supported.
Abstract: Beta-toxin is produced by Clostridium perfringens type B and C strains and is the primary lethal factor in the type C strains. No molecular mechanism has been elucidated for beta-toxin which could be used as a basis for investigating its role in the pathogenesis of these clostridial pathogens. It has been suggested that beta-toxin may be a pore-forming toxin on the basis of weak similarities (10% identity) between the primary structure of beta-toxin and those of the pore-forming alpha-hemolysin and gamma-hemolysin and the leukocidin from Staphylococcus aureus (9). Whether or not beta-toxin is cytotoxic remains unclear; only a single report has suggested that beta-toxin is weakly cytotoxic on intestinal 407 cells (6). However, a previous study suggested that the cytotoxicity associated with beta-toxin preparations was not linked to the beta-toxin itself, but to minor contaminants in the toxin preparation from C. perfringens (11). Recently, Steinthorsdottir et al. demonstrated that beta-toxin could induce the release of arachidonic acid and inositol from human umbilical vein endothelial cells (HUVECs) (32). No cytolytic effects were reported, suggesting that beta-toxin may not be necessarily lethal to these cells. Several other cell types were also tested by these investigators, but they were unresponsive to beta-toxin. C. perfringens type C strains cause necrotic enteritis primarily in pigs, chickens, cattle, sheep, and goats. Although adult animals can contract this disease, it most frequently occurs in the young of these species (34). Piglets are particularly susceptible to type C infections (5, 10, 18, 33), although a similar infection occurs in neonatal calves (7), lambs (8), and goats. During a type C infection, necrosis of the intestine can be extensive; death appears to be the result of toxemia with beta-toxin (reviewed in reference 29). Acute and peracute deaths frequently occur in these animals, suggesting that systemic effects of the toxin are important. In a C. perfringens type C disease of adult sheep, termed “struck,” the animals succumb to the infection so rapidly that they appear to have been struck by lightning. Prior to death, nervous signs such as tetani and opisthotonus have been observed in these animals (reviewed in reference 29), suggesting neurological involvement. Infection of humans by type C strains appears to be largely restricted to certain tribal populations in Papua New Guinea, although infrequent cases of type C infection have occurred in humans throughout the world. Type C infections result in necrotizing enterocolitis (“pigbel”) in these individuals after consumption of undercooked pork during certain ritualistic practices (13). Typically, type C necrotizing enterocolitis in humans resembles the disease in animals. The importance of beta-toxin in both animal and human disease has been demonstrated by immunization studies using a toxoid of beta-toxin. When immunized with the toxoid of beta-toxin, the Papua New Guinea tribespeople experienced a fivefold reduction in the incidence of necrotic enteritis (13), whereas a beta-toxin toxoid administered to infant pigs during an outbreak of necrotizing enterocolitis reduced mortality by approximately 30% (30). In the case of agriculturally important animals, vaccination against type C infections is universally advocated in order to avoid devastating losses. Therefore, beta-toxin plays a key role in the lethal outcome of type C infections, yet we know very little about its mechanism or the cell types it affects. The results presented below demonstrate that beta-toxin is an efficient pore-forming toxin which generates potential-dependent, cation-selective channels in membranes. The channels formed by beta-toxin exhibit characteristics that may provide some insight into the lethal activity of this toxin.

74 citations

Journal ArticleDOI
TL;DR: It is hypothesized that the alpha-latrotoxin molecule has separate functional sites which provide a high-affinity binding to the membrane acceptor, the toxin-induced Ca2+ uptake and toxin-stimulated neurotransmitter release, and a separate part of alpha-Latrotoxin molecules is responsible for the formation of cationic channels in the artificial lipid bilayer.

24 citations

Journal ArticleDOI
TL;DR: In this article, Latroinsectotoxin (LIT) from Latrodectus mactans venom increased the conductance of bilayer lipid membranes (BLM) by inducing channel like activity.

20 citations


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Journal ArticleDOI
TL;DR: The molecular determinants of Listeria virulence and their mechanism of action are described and the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listersia infection is summarized.
Abstract: The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research.

2,139 citations

Journal ArticleDOI
07 Jul 2016-Nature
TL;DR: It is demonstrated that the liposome-leakage and pore-forming activities of the gasdermin-N domain are required for pyroptosis and provide insights into the roles of theGasdermin family in necrosis, immunity and diseases.
Abstract: The N-terminal domains of gasdermin proteins cause pyroptotic cell death by oligomerizing to form membrane pores.

1,567 citations

Journal ArticleDOI
TL;DR: The mechanism of action of three groups of presynaptic neurotoxins that interfere directly with the process of neurotransmitter release is reviewed, whereas presynapses acting on ion channels are not dealt with here.
Abstract: Nerve terminals are specific sites of action of a very large number of toxins produced by many different organisms. The mechanism of action of three groups of presynaptic neurotoxins that interfere directly with the process of neurotransmitter release is reviewed, whereas presynaptic neurotoxins acting on ion channels are not dealt with here. These neurotoxins can be grouped in three large families: 1) the clostridial neurotoxins that act inside nerves and block neurotransmitter release via their metalloproteolytic activity directed specifically on SNARE proteins; 2) the snake presynaptic neurotoxins with phospholipase A(2) activity, whose site of action is still undefined and which induce the release of acethylcholine followed by impairment of synaptic functions; and 3) the excitatory latrotoxin-like neurotoxins that induce a massive release of neurotransmitter at peripheral and central synapses. Their modes of binding, sites of action, and biochemical activities are discussed in relation to the symptoms of the diseases they cause. The use of these toxins in cell biology and neuroscience is considered as well as the therapeutic utilization of the botulinum neurotoxins in human diseases characterized by hyperfunction of cholinergic terminals.

1,196 citations

Journal ArticleDOI
TL;DR: The current understanding of the structural, cellular and clinical aspects of perforin and granzyme biology is discussed, beginning to define and understand a range of human diseases that are associated with a failure to deliver active per forin to target cells.
Abstract: A defining property of cytotoxic lymphocytes is their expression and regulated secretion of potent toxins, including the pore-forming protein perforin and serine protease granzymes. Until recently, mechanisms of pore formation and granzyme transfer into the target cell were poorly understood, but advances in structural and cellular biology have now begun to unravel how synergy between perforin and granzymes brings about target cell death. These and other advances are demonstrating the surprisingly broad pathophysiological roles of the perforin–granzyme pathway, and this has important implications for understanding immune homeostasis and for developing immunotherapies for cancer and other diseases. In particular, we are beginning to define and understand a range of human diseases that are associated with a failure to deliver active perforin to target cells. In this Review, we discuss the current understanding of the structural, cellular and clinical aspects of perforin and granzyme biology.

785 citations

Journal ArticleDOI
TL;DR: Two proteins, an endolysin and a holin, are essential for host lysis by bacteriophage, and constitute one of the most diverse functional groups, with >100 known or putative holin sequences, which form >30 ortholog groups.
Abstract: Two proteins, an endolysin and a holin, are essential for host lysis by bacteriophage. Endolysin is the term for muralytic enzymes that degrade the cell wall; endolysins accumulate in the cytosol fully folded during the vegetative cycle. Holins are small membrane proteins that accumulate in the membrane until, at a specific time that is "programmed" into the holin gene, the membrane suddenly becomes permeabilized to the fully folded endolysin. Destruction of the murein and bursting of the cell are immediate sequelae. Holins control the length of the infective cycle for lytic phages and so are subject to intense evolutionary pressure to achieve lysis at an optimal time. Holins are regulated by protein inhibitors of several different kinds. Holins constitute one of the most diverse functional groups, with >100 known or putative holin sequences, which form >30 ortholog groups.

714 citations