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Sample records for exfoliative toxin types

  1. Identification of first exfoliative toxin in Staphylococcus pseudintermedius.

    PubMed

    Futagawa-Saito, Keiko; Makino, Shinichiroh; Sunaga, Fujiko; Kato, Yukio; Sakurai-Komada, Naomi; Ba-Thein, William; Fukuyasu, Tsuguaki

    2009-12-01

    Staphylococcus aureus, Staphylococcus hyicus, and Staphylococcus chromogenes are known to cause skin infections in human or animals by producing exfoliative toxins (ETs). Staphylococcus pseudintermedius can also cause canine pyoderma, but no exfoliative toxins or similar toxins have been reported. PCR with degenerate primers targeted to the conserved regions in ETA, ETB, and ETD from S. aureus and SHETB from S. hyicus, and subsequent chromosome walking identified a novel gene, designated as exi (exfoliative toxin of pseudintermedius) in S. pseudintermedius. EXI had significant homologies with the exfoliative toxins (43-68% identity), particularly with ETB (67.1%), ETD (67.9%), and SHETB (65.1%). Phylogenetic analysis showed close relation between EXI and ETB with a bootstrap value of 80%. Neonatal mice injected with the crude proteins from the culture supernatant or recombinant EXI showed gross blisters and/or characteristic skin exfoliation. The prevalence of exi assessed by dot-blot hybridization was 23.3% (10/43) in S. pseudintermedius isolates from canine pyoderma. The EXI reported herein is the first exfoliative toxin identified in S. pseudintermedius. PMID:19891731

  2. Crystal structure of Staphylococcus aureus exfoliative toxin D-like protein: Structural basis for the high specificity of exfoliative toxins.

    PubMed

    Mariutti, Ricardo B; Souza, Tatiana A C B; Ullah, Anwar; Caruso, Icaro P; de Moraes, Fábio R; Zanphorlin, Leticia M; Tartaglia, Natayme R; Seyffert, Nubia; Azevedo, Vasco A; Le Loir, Yves; Murakami, Mário T; Arni, Raghuvir K

    2015-11-01

    Exfoliative toxins are serine proteases secreted by Staphylococcus aureus that are associated with toxin-mediated staphylococcal syndromes. To date, four different serotypes of exfoliative toxins have been identified and 3 of them (ETA, ETB, and ETD) are linked to human infection. Among these toxins, only the ETD structure remained unknown, limiting our understanding of the structural determinants for the functional differentiation between these toxins. We recently identified an ETD-like protein associated to S. aureus strains involved in mild mastitis in sheep. The crystal structure of this ETD-like protein was determined at 1.95 Å resolution and the structural analysis provide insights into the oligomerization, stability and specificity and enabled a comprehensive structural comparison with ETA and ETB. Despite the highly conserved molecular architecture, significant differences in the composition of the loops and in both the N- and C-terminal α-helices seem to define ETD-like specificity. Molecular dynamics simulations indicate that these regions defining ET specificity present different degrees of flexibility and may undergo conformational changes upon substrate recognition and binding. DLS and AUC experiments indicated that the ETD-like is monomeric in solution whereas it is present as a dimer in the asymmetric unit indicating that oligomerization is not related to functional differentiation among these toxins. Differential scanning calorimetry and circular dichroism assays demonstrated an endothermic transition centered at 52 °C, and an exothermic aggregation in temperatures up to 64 °C. All these together provide insights about the mode of action of a toxin often secreted in syndromes that are not associated with either ETA or ETB. PMID:26299923

  3. A double outbreak of exfoliative toxin-producing strains of Staphylococcus aureus in a maternity unit.

    PubMed

    Dave, J; Reith, S; Nash, J Q; Marples, R R; Dulake, C

    1994-02-01

    This report describes a double outbreak of staphylococcal scalded skin syndrome (SSSS) in which two distinct tetracycline-resistant strains of Staphylococcus aureus producing different exfoliative toxins were involved. In the first phase the daytime staff of the delivery unit and eczematous skin conditions in midwives were implicated as the probable source. In the second phase a source within a post-natal ward was suggested with local cross-infection. In the final phase both sources were epidemiologically linked to cases of SSSS. Because early discharge was the policy of the unit many cases presented in the community rather than in the hospital. Confirmation of epidemiological findings was provided by additional laboratory studies. Two distinct strains of S. aureus could be defined, differing in phage-typing patterns, the exfoliative toxin produced, plasmid profile, cadmium resistance and bacteriocin production. Strict care in hand washing with a chlorhexidine-containing detergent was an important control measure. PMID:8119349

  4. Clinical, Microbial, and Biochemical Aspects of the Exfoliative Toxins Causing Staphylococcal Scalded-Skin Syndrome

    PubMed Central

    Ladhani, Shamez; Joannou, Christopher L.; Lochrie, Denise P.; Evans, Robert W.; Poston, Susan M.

    1999-01-01

    The exfoliative (epidermolytic) toxins of Staphylococcus aureus are the causative agents of the staphylococcal scalded-skin syndrome (SSSS), a blistering skin disorder that predominantly affects children. Clinical features of SSSS vary along a spectrum, ranging from a few localized blisters to generalized exfoliation covering almost the entire body. The toxins act specifically at the zona granulosa of the epidermis to produce the characteristic exfoliation, although the mechanism by which this is achieved is still poorly understood. Despite the availability of antibiotics, SSSS carries a significant mortality rate, particularly among neonates with secondary complications of epidermal loss and among adults with underlying diseases. The aim of this article is to provide a comprehensive review of the literature spanning more than a century and to cover all aspects of the disease. The epidemiology, clinical features, potential complications, risk factors, susceptibility, diagnosis, differential diagnoses, investigations currently available, treatment options, and preventive measures are all discussed in detail. Recent crystallographic data on the toxins has provided us with a clearer and more defined approach to studying the disease. Understanding their mode of action has important implications in future treatment and prevention of SSSS and other diseases, and knowledge of their specific site of action may provide a useful tool for physiologists, dermatologists, and pharmacologists. PMID:10194458

  5. Keratinocytes produce IL-6 in response to desmoglein 1 cleavage by Staphylococcus aureus exfoliative toxin A.

    PubMed

    Rolle, Cleo E; Chen, Juan; Pastar, Irena; Cardenas, Tatiana C P; Perez, Roberto; Hower, Suzanne; Ferracci, Franco; Snyder, Richard; Tomic-Canic, Marjana; Plano, Lisa R W

    2013-12-01

    Many skin infections are caused by Staphylococcus aureus, a bacterial pathogen that produces virulence factors associated with these conditions such as exfoliative toxins A and B (ETA, ETB) and the leukotoxin Panton-Valentine leukocidin (PVL). Herein, we examine the potential of skin-infecting S. aureus to produce virulence factors and their impact on the local immune response. Toxin gene profiles were generated from 188 S. aureus isolated as single infecting organisms from skin lesions and demonstrated a higher potential to express ETA, ETB, and PVL than community isolates (p < 0.001). Within the study isolate group, the prevalence of genes encoding PVL was higher among methicillin-resistant S. aureus (MRSA; n = 49), while genes encoding ETs were more prevalent in methicillin-susceptible S. aureus (MSSA; n = 139). When lesion-associated white blood cell (WBC) counts were dichotomized into high- or low-WBC-count-associated bacteria, the gene for ETA was found to be associated with a low WBC count among MSSA (p = 0.001). The ETA-induced mouse model of staphylococcal scalded skin syndrome was used to investigate the link between ETA and cytokine production. Elevated IL-6 levels in the serum and increased expression of IL-6 mRNA in the skin were detected in response to ETA exposure. These findings were recapitulated in vitro using primary human keratinocytes. Thus, S. aureus may influence the local immune response via ETA cleavage of desmoglein 1 and the induction of cutaneous IL-6 expression. PMID:24287883

  6. Staphylococcus sciuri Exfoliative Toxin C (ExhC) is a Necrosis-Inducer for Mammalian Cells

    PubMed Central

    Li, Haihua; Wang, Yongqiang; Ding, Lin; Zheng, Shijun J.

    2011-01-01

    Staphylococcus sciuri (S. sciuri) is a rare pathogen in humans, but it can cause a wide array of human infections. Recently a S. sciuri isolate (HBXX06) was reported to cause fatal exudative epidermitis (EE) in piglets and thus considered as a potential zoonotic agent. To investigate the pathogenicity of this bacterium, we cloned exfoliative toxin C (ExhC), a major toxin of the S. sciuri isolate and performed functional analysis of the recombinant ExhC-his (rExhC) protein using in vitro cell cultures and newborn mice as models. We found that rExhC could induce necrosis in multiple cell lines and peritoneal macrophages as well as skin lesions in newborn mice, and that the rExhC-induced necrosis in cells or skin lesions in newborn mice could be completely abolished if amino acids 79-128 of rExhC were deleted or blocked with a monoclonal antibody (3E4), indicating aa 79-128 portion as an essential necrosis-inducing domain. This information contributes to further understandings of the mechanisms underlying S. sciuri infection. PMID:21829591

  7. Production and properties of a staphylococcin genetically controlled by the staphylococcal plasmid for exfoliative toxin synthesis.

    PubMed Central

    Rogolsky, M; Wiley, B B

    1977-01-01

    Previous data from this laboratory showed that certain phage group 2 staphylococci contain a large 56S virulence plasmid containing genes that code for both exfoliative toxin (ET) and a specific staphylococcin. Optimal cultural conditions for bacteriocin production were similar to those found for ET production. The bacteriocin is an extracellular product produced in small quantities that can be neither extracted from cell pellets with 1 M NaCl nor induced with mitomycin C. The staphylococcin is active against a wide variety of gram-positive organisms and also against group 2 staphylococcal strains that have been cured of the plasmid carrying the staphylococcin marker. The bacteriocin is not inactivated by oxidation, mechanical agitation, or boiling for 15 min. It is sensitive to the action of trypsin and Pronase but not lysostaphin and is stable within a pH range of 4 to 9. It has an isoelectric point of approximately 7.7. Removal of the ampholytes and glycerol from electrofocused staphylococcin preparations resulted in total loss of bacteriocin activity. PMID:870429

  8. Emergence of Staphylococcus aureus carrying multiple drug resistance genes on a plasmid encoding exfoliative toxin B.

    PubMed

    Hisatsune, Junzo; Hirakawa, Hideki; Yamaguchi, Takayuki; Fudaba, Yasuyuki; Oshima, Kenshiro; Hattori, Masahira; Kato, Fuminori; Kayama, Shizuo; Sugai, Motoyuki

    2013-12-01

    We report the complete nucleotide sequence and analysis of pETBTY825, a Staphylococcus aureus TY825 plasmid encoding exfoliative toxin B (ETB). S. aureus TY825 is a clinical isolate obtained from an impetigo patient in 2002. The size of pETBTY825, 60.6 kbp, was unexpectedly larger than that of the archetype pETBTY4 (∼30 kbp). Genomic comparison of the plasmids shows that pETBTY825 has the archetype pETBTY4 as the backbone and has a single large extra DNA region of 22.4 kbp. The extra DNA region contains genes for resistance to aminoglycoside [aac(6')/aph(2″)], macrolide (msrA), and penicillin (blaZ). A plasmid deletion experiment indicated that these three resistance elements were functionally active. We retrospectively examined the resistance profile of the clinical ETB-producing S. aureus strains isolated in 1977 to 2007 using a MIC determination with gentamicin (GM), arbekacin (ABK), and erythromycin (EM) and by PCR analyses for aac(6')/aph(2″) and msrA using purified plasmid preparations. The ETB-producing S. aureus strains began to display high resistance to GM, which was parallel with the detection of aac(6')/aph(2″) and mecA, after 1990. Conversely, there was no significant change in the ABK MIC during the testing period, although it had a tendency to slightly increase. After 2001, isolates resistant to EM significantly increased; however, msrA was hardly detected in ETB-producing S. aureus strains, and only five isolates were positive for both aac(6')/aph(2″) and msrA. In this study, we report the emergence of a fusion plasmid carrying the toxin gene etb and drug resistance genes. Prevalence of the pETBTY825 carrier may further increase the clinical threat, since ETB-producing S. aureus is closely related to more severe impetigo or staphylococcal scalded-skin syndrome (SSSS), which requires a general antimicrobial treatment. PMID:24080652

  9. Draft Genome Sequences of Exfoliative Toxin A-Producing Staphylococcus aureus Strains B-7772 and B-7777 (CC8/ST2993) and B-7774 (CC15/ST2126), Isolated in a Maternity Hospital in the Central Federal District of Russia

    PubMed Central

    Skryabin, Yury; Kislichkina, Angelina; Bogun, Alexandr; Korobova, Olga; Mayskaya, Nadezhda; Shemyakin, Igor; Dyatlov, Ivan

    2016-01-01

    Staphylococcus aureus clonal complex 8 (CC8) has not been associated with staphylococcal scalded-skin syndrome (SSSS) in newborns and exfoliative toxin genes. Here, we report the draft genome sequences of exfoliative toxin A-producing B-7772, B-7777 (both CC8), and B-7774 (CC15) strains associated with SSSS in newborns. PMID:26941146

  10. A novel positive regulatory element for exfoliative toxin A gene expression in Staphylococcus aureus.

    PubMed

    Sakurai, Susumu; Suzuki, Hitoshi; Hata, Toshiaki; Yoshizawa, Yukio; Nakayama, Ritsuko; Machida, Katsuhiko; Masuda, Shogo; Tsukiyama, Takashi

    2004-04-01

    A 1.4 kb positive regulatory element (ETA(exp)) that controls staphylococcal exfoliative toxin A (sETA) transcription was cloned from Staphylococcus aureus. ETA(exp) is located upstream of the cloned 5.8 kb eta gene (etaJ1) obtained from the chomosomal DNA of S. aureus ZM, the standard ETA-producing strain. The cETA prepared from an Escherichia coli transformant into which the recombinant plasmid petaJ1 (5.8 kb eta/pUC9) had been introduced was expressed at high levels in the culture supernatant and the ammonium-sulfate-precipitated culture supernatant fraction as shown by immunoblotting and the single radial immunodiffusion test. However, cETA produced by the recombinant plasmid petaJ3 containing the 1.7 kb eta sequence (etaJ3) with a 1.45 kb ETA(exp)-deficient eta fragment (1.7 kb eta/pUC9) obtained from the 5.8 kb eta sequence by subcloning was not detected in either the culture supernatant or the ammonium-sulfate-precipitated culture supernatant fraction (167-fold concentrate of the culture supernatant) by immunoblotting or the single radial immunodiffusion test. A large amount of cETA was produced by the 1.7 kb eta sequence when it was linked to ETA(exp) amplified by PCR (1.7 kb eta-ETA(exp)/pUC9), regardless of the orientation of ETA(exp) insertion. Northern blot hybridization showed lower levels of the transcripts of the 1.7 kb eta sequence than of the 5.8 kb eta sequence. The rsETA prepared from an S. aureus transformant into which the recombinant plasmid 3.4 kb eta-ETA(exp)/pYT3 (pYT3-etaJ6) had been introduced was expressed at high levels in the culture supernatant fraction as shown by the latex agglutination test. However, the agglutination titre in the culture supernatant fraction of rsETA produced by the recombinant plasmid (1.7 kb eta/pYT3) containing the 1.7 kb eta sequence carrying the 1.4 kb ETA(exp)-deficient eta fragment (pYT3-etaJ3) was 2500-4000 times lower than that of pYT3-etaJ6. PMID:15073304

  11. Sequence Analysis of Staphylococcus hyicus ATCC 11249T, an Etiological Agent of Exudative Epidermitis in Swine, Reveals a Type VII Secretion System Locus and a Novel 116-Kilobase Genomic Island Harboring Toxin-Encoding Genes

    PubMed Central

    Foecking, Mark F.; Hsieh, Hsin-Yeh; Adkins, Pamela R. F.; Stewart, George C.; Middleton, John R.

    2015-01-01

    Staphylococcus hyicus is the primary etiological agent of exudative epidermitis in swine. Analysis of the complete genome sequence of the type strain revealed a locus encoding a type VII secretion system and a large chromosomal island harboring the genes encoding exfoliative toxin ExhA and an EDIN toxin homolog. PMID:25700402

  12. Structural similarities and differences in Staphylococcus aureus exfoliative toxins A and B as revealed by their crystal structures.

    PubMed Central

    Papageorgiou, A. C.; Plano, L. R.; Collins, C. M.; Acharya, K. R.

    2000-01-01

    Staphylococcal aureus epidermolytic toxins (ETs) A and B are responsible for the induction of staphylococcal scalded skin syndrome, a disease of neonates and young children. The clinical features of this syndrome vary from localized blisters to severe exfoliation affecting most of the body surface. Comparison of the crystal structures of two subtypes of ETs-rETA (at 2.0 A resolution), rETB (at 2.8 A resolution), and an active site variant of rETA, Ser195Ala at 2.0 A resolution has demonstrated that their overall topology resembles that of a "trypsin-like" serine protease, but with significant differences at the N- and C-termini and loop regions. The details of the catalytic site in both ET structures are very similar to those in glutamate-specific serine proteases, suggesting a common catalytic mechanism. However, the "oxyanion hole," which is part of the catalytic sites of glutamate specific serine proteases, is in the closed or inactive conformation for rETA, yet in the open or active conformation for rETB. The ETs contain a unique amphipathic helix at the N-terminus, and it appears to be involved in optimizing the conformation of the catalytic site residues. Determination of the structure of the rETA catalytic site variant, Ser195Ala, showed no significant perturbation at the active site, establishing that the loss of biological and esterolytic activity can be attributed solely to disruption of the catalytic serine residue. Finally, the crystal structure of ETs, together with biochemical data and mutagenesis studies, strongly confirms the classification of these molecules as "serine proteases" rather than "superantigens." PMID:10752623

  13. Detection and genetic characterization of PVL-positive ST8-MRSA-IVa and exfoliative toxin D-positive European CA-MRSA-Like ST1931 (CC80) MRSA-IVa strains in Bangladesh.

    PubMed

    Paul, Shyamal Kumar; Ghosh, Souvik; Kawaguchiya, Mitsuyo; Urushibara, Noriko; Hossain, Mohammad Akram; Ahmed, Salma; Mahmud, Chand; Jilani, Md Shariful Alam; Haq, Jalaluddin Ashraful; Ahmed, Abdullah Akhtar; Kobayashi, Nobumichi

    2014-08-01

    Severe skin lesions caused by Staphylococcus aureus infection are associated with production from bacterial cells of Panton-Valentine leukocidin (PVL), a typical virulence factor of community-acquired methicillin-resistant S. aureus (CA-MRSA), as well as other toxins represented by exfoliative toxins. Through a retrospective study of 26 S. aureus strains isolated from skin lesions of diabetic patients admitted to a hospital in Bangladesh, 2 PVL-gene-positive MRSA-IVa strains and 8 PVL-negative, exfoliative toxin D (ETD) gene (etd)-positive MRSA-IVa strains were isolated. A PVL-positive MRSA-IVa strain had a type I arginine catabolic mobile element (ACME), belonged to ST8/agr-type I/spa-type t121 (a variant of t008), and harbored blaZ, tet(K), msrA, and aph(3')-IIIa, which are mostly typical characteristics found in USA300, a predominant CA-MRSA clone in the United States. Another PVL-positive MRSA strain, belonging to ST1929 (CC88)/agr-type III/spa-type t3341, was negative for ACME, but possessed blaZ and tet(K). The etd-positive MRSA-IVa strains possessed the epidermal cell differentiation inhibitor B (EDIN-B)-encoding gene (edinB) and belonged to ST1931 (CC80)/agr-type III/spa-type t11023 (a variant of t044), which was genetic trait similar to that of the European CA-MRSA ST80 clone. However, unlike the European ST80 strains, the etd-positive MRSA strains detected in the present study harbored seb, sek, and seq, while they were negative for tet(K), aph(3')-IIIa, and fusB, showing susceptibility to fusidic acid. These findings suggested that etd-positive ST1931 MRSA strains belong to the same lineage as the European ST80 MRSA clone, evolving from a common ancestral clone via acquisition of a different pathogenicity island. This is the first report of a USA300-like MRSA-IV strain, PVL-positive ST1929 (CC88) MRSA-IV, and European ST80 CA-MRSA-like etd-positive ST1931 (CC80) MRSA-IV strains isolated in Bangladesh. PMID:24552553

  14. Characterization of toxin plasmids in Clostridium perfringens type C isolates.

    PubMed

    Gurjar, Abhijit; Li, Jihong; McClane, Bruce A

    2010-11-01

    Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasmid borne among a collection of type C isolates. Those analyses revealed that the surveyed type C isolates carry their beta toxin-encoding gene (cpb) on plasmids ranging in size from ∼65 to ∼110 kb. When present in these type C isolates, the beta2 toxin gene localized to plasmids distinct from the cpb plasmid. However, some enterotoxin-positive type C isolates appeared to carry their enterotoxin-encoding cpe gene on a cpb plasmid. The tpeL gene encoding the large clostridial cytotoxin was localized to the cpb plasmids of some cpe-negative type C isolates. The cpb plasmids in most surveyed isolates were found to carry both IS1151 sequences and the tcp genes, which can mediate conjugative C. perfringens plasmid transfer. A dcm gene, which is often present near C. perfringens plasmid-borne toxin genes, was identified upstream of the cpb gene in many type C isolates. Overlapping PCR analyses suggested that the toxin-encoding plasmids of the surveyed type C isolates differ from the cpe plasmids of type A isolates. These findings provide new insight into plasmids of proven or potential importance for type C virulence. PMID:20823204

  15. Linking bacterial type I toxins with their actions.

    PubMed

    Brielle, Régine; Pinel-Marie, Marie-Laure; Felden, Brice

    2016-04-01

    Bacterial type I toxin-antitoxin systems consist of stable toxin-encoding mRNAs whose expression is counteracted by unstable RNA antitoxins. Accumulating evidence suggests that these players belong to broad regulatory networks influencing overall bacterial physiology. The majority of known transmembrane type I toxic peptides have conserved structural characteristics. However, recent studies demonstrated that their mechanisms of toxicity are diverse and complex. To better assess the current state of the art, type I toxins can be grouped into two classes according to their location and mechanisms of action: membrane-associated toxins acting by pore formation and/or by nucleoid condensation; and cytosolic toxins inducing nucleic acid cleavage. This classification will evolve as a result of future investigations. PMID:26874964

  16. Botulinum toxin type A for the management of glabellar rhytids

    PubMed Central

    Tremaine, Anne Marie; McCullough, Jerry L

    2010-01-01

    There is an increasing demand for minimally-invasive cosmetic procedures to arrest the aging process. Botulinum toxin type A injections are the most commonly used nonsurgical cosmetic procedures in the United States. There has been research spanning over two decades dedicated to safety, efficacy, dosing, and complications of botulinum toxin type A. There are now two Food and Drug Administration (FDA) approved botulinum toxin type A options in the United States: Botox® and Dysport™, with new advances being made in the field. PMID:21437056

  17. Purification of Clostridium botulinum type G progenitor toxin.

    PubMed

    Nukina, M; Mochida, Y; Sakaguchi, S; Sakaguchi, G

    1988-04-01

    Clostridium botulinum type G cultured for 6 days at 30 degrees C in proteose peptone-yeast extract-glucose medium produced toxin of 1.3 x 10(4) LD50/ml. The toxin was precipitated at pH 4.0, extracted with 0.2 M phosphate buffer, pH 6.0, and activated with trypsin. Sonic treatment and trypsinization of the residual precipitate released additional toxin, the toxicity of which corresponded to that detected in whole culture. Activated toxin obtained from the first extract and that from the residual precipitate were combined and purified by salting out, acid precipitation, gel filtration on Sephadex G-200, chromatography on SP-Sephadex, and a second gel filtration on Sephadex G-200. The yield of purified toxin from 10 liters of culture was 22.9 mg an 1.1 X 10(8) mouse ip LD50 with a specific toxicity of 3.0 X 10(7) mouse ip LD50/mg nitrogen. The molecular weight of the toxin was about 500,000, corresponding to that of L toxin of the other types. No M nor LL toxin was detected. PMID:3293334

  18. International Typing Study of Toxin A-Negative, Toxin B-Positive Clostridium difficile Variants

    PubMed Central

    Johnson, Stuart; Sambol, Susan P.; Brazier, Jon S.; Delmée, Michel; Avesani, V.; Merrigan, Michelle M.; Gerding, Dale N.

    2003-01-01

    Clinically important strains of Clostridium difficile that do not produce toxin A but produce toxin B and are cytotoxic (A−/B+) have been reported from multiple countries. In order to compare the relatedness of these strains, we typed 23 A−/B+ C. difficile isolates from the United Kingdom (6 isolates), Belgium (11 isolates), and the United States (6 isolates) by three well-described typing methods. Restriction endonuclease analysis (REA), PCR ribotyping, and serogrouping differentiated 11, 4, and 3 different strain types, respectively. Twenty-one of the 23 A−/B+ variants had a 1.8-kb truncation of the toxin A gene characteristic of toxinotype VIII strains; 20 of the 21 toxinotype VIII-like strains were PCR type 17. PCR type 17 isolates could be differentiated into two separate strain groups by serogrouping and by REA. REA further discriminated these isolates into eight subgroups (REA types). PCR type 17-serogroup F-REA group CF isolates were recovered from all three countries, and one specific REA type, CF4, was recovered from patients with C. difficile disease in the United Kingdom and the United States. C. difficile A−/B+ variants of apparent clonal origin are widely distributed in Europe and North America. PMID:12682143

  19. Longitudinal Phonatory Characteristics after Botulinum Toxin Type A Injection.

    ERIC Educational Resources Information Center

    Fisher, Kimberly V.; And Others

    1996-01-01

    A study investigated the long-term effects of a Botulinum Toxin Type A injection on the glottal competency of a man with adductor spasmodic dysphonia. Results suggest that change in degree of glottal adduction over time can be observed even when vocal instability is present within each recording session. (CR)

  20. Clostridium perfringens type-D enterotoxaemia in cattle: the diagnostic significance of intestinal epsilon toxin.

    PubMed

    Jones, A L; Dagleish, M P; Caldow, G L

    2015-10-17

    The aims of this study were to describe 42 cases of Clostridium perfringens type-D enterotoxaemia in cattle seen between 2003 and 2014 and to determine the diagnostic value of detecting epsilon toxin in bovine intestinal content. All cases in the series had histological brain changes considered pathognomonic for C. perfringens type-D enterotoxaemia in sheep and goats and the epsilon toxin of C. perfringens was concurrently detected in the intestinal contents of 15 (36 per cent) cases. The data from the case series indicate that intestinal epsilon toxin has a sensitivity of 56 per cent compared with histology of the brain for diagnosis of bovine C. perfringens type-D enterotoxaemia. The diagnostic specificity of detecting epsilon toxin in bovine intestinal content was investigated by screening intestinal contents of 60 bovine carcases submitted for postmortem examination. Epsilon toxin was detected in 11 (18 per cent) carcases but no pathognomonic histological brain change was found in any. The specificity of intestinal epsilon toxin was estimated to be 80.4 per cent. These studies demonstrate that for a definitive diagnosis of C. perfringens type-D enterotoxaemia in cattle histological examination of the brain is essential as the presence of epsilon toxin in the intestinal contents alone is neither sensitive nor specific enough. PMID:26428898

  1. Nuclear morphometric and morphological analysis of exfoliated buccal and tongue dorsum cells in type-1 diabetic patients

    PubMed Central

    Oz, Zehra Safi; Bektas, Sibel; Battal, Fatih; Atmaca, Hulusi; Ermis, Bahri

    2014-01-01

    Background: Diabetes mellitus type 1 that results from immunologically mediated damage to the β-cells in the pancreas. Diabetes mellitus is characterized by recurrent or persistent hyperglycemia. Hyperglycemia can be associated with salivary gland dysfunction and alterations in the oral epithelial cells. Aim: The aim of this study was to evaluate the qualitative and quantitative changes in buccal and tongue dorsum epithelial cells using an exfoliative cytology method in type 1 diabetic patients. Materials and Methods: We performed light microscopic analysis of the buccal and tongue dorsum smears in thirty type 1 diabetic patients and thirty healthy individuals. The oral smears were stained using Papanicolaou method for cytological examination and nuclear morphometric analysis. In each case, the mean nuclear area, perimeter, length, breadth, and roundness factor were evaluated in each smear using the image analysis software (Q Win, Leica™). Results: The nuclear area, length, breadth, and perimeters were significantly higher in the diabetic group from tongue dorsum smear than that of the control group (P < 0.05). In the cytological examination, karyorrhexis-karyolysis-karyopyknosis, binucleation, nuclear membrane irregularity, cytoplasmic polymorphism, perinuclear halo were observed in oral smears with type 1 diabetic patients. Binucleation (P = 0.002) and nuclear membrane irregularity (P = 0.024) were significantly more common in buccal smears of diabetic group. Furthermore, the sensitivity of buccal mucosa was significantly higher in the diabetic group (P = 0.006). Conclusion: The light microscopic and nuclear morphometric study indicates that type 1 diabetes can produce morphological and nuclear morphometric changes in the oral mucosa that are noticeable with exfoliative cytology. PMID:25538382

  2. Clostridium perfringens type A–E toxin plasmids

    PubMed Central

    Freedman, John C.; Theoret, James R.; Wisniewski, Jessica A.; Uzal, Francisco A.; Rood, Julian I.; McClane, Bruce A.

    2014-01-01

    Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C. perfringens strains. The association of many toxin genes with insertion sequences and conjugative plasmids provides virulence flexibility when causing intestinal infections. However, incompatibility issues apparently limit the number of toxin plasmids maintained by a single cell. PMID:25283728

  3. Correlation between thermal gradient and flexure-type deformation as a potential trigger for exfoliation-related rock falls (Invited)

    NASA Astrophysics Data System (ADS)

    Collins, B. D.; Stock, G. M.

    2010-12-01

    temperatures. Consecutive terrestrial lidar data sets collected at a 12-hour interval during this period confirm the magnitude and geometric configuration of deformation. Temperature and light data indicate a direct link to flake deformation, with peak expansion (crack opening) in late-afternoon, within four hours of peak solar radiation and within two hours after peak temperatures (up to 50°C). Likewise, peak contraction (crack closing) occurs in mid-morning at opposite diurnal cycle, synchronous with low solar radiation and air temperature (down to -1°C). We interpret the lag between solar radiation, temperature and deformation to be caused by the response time needed for thermal propagation through the granitic flake itself, but infer that temperature may play the dominant role. With continued data collection we anticipate assessing potential cumulative deformation of the flake, which could contribute to moment-inducing tensile stresses within the entire flake or to crack tip propagation at the attachment points. Thus, this data may provide an explanation for many exfoliation-type rock falls occurring in Yosemite and elsewhere.

  4. Different types of toxins targeting TRPV1 in pain.

    PubMed

    Min, Jia-Wei; Liu, Wan-Hong; He, Xiao-Hua; Peng, Bi-Wen

    2013-09-01

    The transient receptor potential vanilloid 1(TRPV1) channels are members of the transient receptor potential (TRP) superfamily. Members of this family are expressed in primary sensory neurons and are best known for their role in nociception and sensory transmission. Multiple painful stimuli can activate these channels. In this review, we discussed the mechanisms of different types of venoms that target TRPV1, such as scorpion venom, botulinum neurotoxin, spider toxin, ciguatera fish poisoning (CFP) and neurotoxic shellfish poisoning (NSP). Some of these toxins activate TRPV1; however, some do not. Regardless of TRPV1 inhibition or activation, they occur through different pathways. For example, BoNT/A decreases TRPV1 expression levels by blocking TRPV1 trafficking to the plasma membrane, although the exact mechanism is still under debate. Vanillotoxins from tarantula (Psalmopoeus cambridgei) are proposed to activate TRPV1 via interaction with a region of TRPV1 that is homologous to voltage-dependent ion channels. Here, we offer a description of the present state of knowledge for this complex subject. PMID:23732125

  5. Typing of Clostridium perfringens by in vitro amplification of toxin genes.

    PubMed

    Daube, G; China, B; Simon, P; Hvala, K; Mainil, J

    1994-12-01

    The strains of Clostridium perfringens are classified according to major toxins produced. Classically, this determination involves the seroneutralization of their lethal effect in mice. However, this method requires specific antisera and a large number of mice. In this work, a new typing method was developed based on the amplification of toxin genes by polymerase chain reaction (PCR). By combination of several pairs of primers, the toxinotype of a Cl. perfringens strain was determined by looking at the pattern of bands on an agarose gel electrophoresis. This mixture contained primers amplifying simultaneously a part of alpha-toxin, beta-toxin, epsilon-toxin and enterotoxin genes. In order to distinguish between toxinotype A and E, the l-toxin gene fragment must be amplified in a separate PCR reaction. Moreover, with the primers combination, in most cases, a PCR product corresponding to the alpha-toxin gene was obtained from direct enrichments of animal intestinal contents. PMID:7822224

  6. A New Type of Toxin A-Negative, Toxin B-Positive Clostridium difficile Strain Lacking a Complete tcdA Gene

    PubMed Central

    Marín, Mercedes; Martín, Adoración; Rupnik, Maja

    2014-01-01

    Toxins A and B are the main virulence factors of Clostridium difficile and are the targets for molecular diagnostic tests. Here, we describe a new toxin A-negative, toxin B-positive, binary toxin CDT (Clostridium difficile transferase)-negative (A− B+ CDT−) toxinotype (XXXII) characterized by a variant type of pathogenicity locus (PaLoc) without tcdA and with atypical organization of the PaLoc integration site. PMID:25428159

  7. Phage Types and Genotypes of Shiga Toxin-Producing Escherichia coli O157 in Finland

    PubMed Central

    Saari, Marjut; Cheasty, Thomas; Leino, Kirsikka; Siitonen, Anja

    2001-01-01

    This study examined Shiga toxin-producing Escherichia coli (STEC) O157, using phage typing, pulsed-field gel electrophoresis, and typing of Shiga toxin variant genes by PCR with restriction fragment length polymorphism in an epidemiological survey of STEC O157 isolated from humans in Finland between 1990 and 1999. PMID:11230443

  8. Distinct type I and type II toxin-antitoxin modules control Salmonella lifestyle inside eukaryotic cells

    PubMed Central

    Lobato-Márquez, Damián; Moreno-Córdoba, Inmaculada; Figueroa, Virginia; Díaz-Orejas, Ramón; García-del Portillo, Francisco

    2015-01-01

    Toxin-antitoxin (TA) modules contribute to the generation of non-growing cells in response to stress. These modules abound in bacterial pathogens although the bases for this profusion remain largely unknown. Using the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as a model, here we show that a selected group of TA modules impact bacterial fitness inside eukaryotic cells. We characterized in this pathogen twenty-seven TA modules, including type I and type II TA modules encoding antisense RNA and proteinaceous antitoxins, respectively. Proteomic and gene expression analyses revealed that the pathogen produces numerous toxins of TA modules inside eukaryotic cells. Among these, the toxins HokST, LdrAST, and TisBST, encoded by type I TA modules and T4ST and VapC2ST, encoded by type II TA modules, promote bacterial survival inside fibroblasts. In contrast, only VapC2ST shows that positive effect in bacterial fitness when the pathogen infects epithelial cells. These results illustrate how S. Typhimurium uses distinct type I and type II TA modules to regulate its intracellular lifestyle in varied host cell types. This function specialization might explain why the number of TA modules increased in intracellular bacterial pathogens. PMID:25792384

  9. Brain Metabolic Changes of Cervical Dystonia with Spinocerebellar Ataxia Type 1 after Botulinum Toxin Therapy.

    PubMed

    Kikuchi, Akio; Takeda, Atsushi; Sugeno, Naoto; Miura, Emiko; Kato, Kazuhiro; Hasegawa, Takafumi; Baba, Toru; Konno, Masatoshi; Oshima, Ryuji; Watanuki, Shoichi; Hiraoka, Kotaro; Tashiro, Manabu; Aoki, Masashi

    2016-01-01

    We occasionally observe long-term remission of cervical dystonia after several botulinum toxin treatments. However, botulinum toxin transiently acts on neuromuscular junctions. We herein report that a cervical dystonia patient with spinocerebellar ataxia type 1 could have long-term remission as a result of the depression of hypermetabolism in the bilateral putamen and primary sensorimotor cortex after botulinum toxin therapy. We suggest that botulinum toxin impacts the central nervous system, causing prolonged improvement through the normalization of basal ganglia circuits in addition to its effects at neuromuscular junctions. PMID:27432104

  10. Type VI Secretion System Toxins Horizontally Shared between Marine Bacteria

    PubMed Central

    Salomon, Dor; Klimko, John A.; Trudgian, David C.; Kinch, Lisa N.; Grishin, Nick V.; Mirzaei, Hamid; Orth, Kim

    2015-01-01

    The type VI secretion system (T6SS) is a widespread protein secretion apparatus used by Gram-negative bacteria to deliver toxic effector proteins into adjacent bacterial or host cells. Here, we uncovered a role in interbacterial competition for the two T6SSs encoded by the marine pathogen Vibrio alginolyticus. Using comparative proteomics and genetics, we identified their effector repertoires. In addition to the previously described effector V12G01_02265, we identified three new effectors secreted by T6SS1, indicating that the T6SS1 secretes at least four antibacterial effectors, of which three are members of the MIX-effector class. We also showed that the T6SS2 secretes at least three antibacterial effectors. Our findings revealed that many MIX-effectors belonging to clan V are “orphan” effectors that neighbor mobile elements and are shared between marine bacteria via horizontal gene transfer. We demonstrated that a MIX V-effector from V. alginolyticus is a functional T6SS effector when ectopically expressed in another Vibrio species. We propose that mobile MIX V-effectors serve as an environmental reservoir of T6SS effectors that are shared and used to diversify antibacterial toxin repertoires in marine bacteria, resulting in enhanced competitive fitness. PMID:26305100

  11. Selection of a Clostridium perfringens type D epsilon toxin producer via dot-blot test.

    PubMed

    Gonçalves, Luciana A; Lobato, Zélia I P; Silva, Rodrigo O S; Salvarani, Felipe M; Pires, Prhiscylla S; Assis, Ronnie A; Lobato, Francisco C F

    2009-11-01

    Clostridium perfringens type D produces enterotoxemia, an enteric disease in ruminants, also known as pulpy kidney disease. Caused by epsilon toxin, enterotoxemia is a major exotoxin produced by this microorganism. Epsilon toxin is also the main component of vaccines against this enteric disorder. In this study, a standardized dot-blot was used to choose strains of C. perfringens type D that are producers of epsilon toxin. Clones producing epsilon toxin were chosen by limiting dilution; after three passages, lethal minimum dose titers were determined by soroneutralization test in mice. These clones produced epsilon toxin 240 times more concentrated than the original strain. The presence of the epsilon toxin gene (etx) was verified by polymerase chain reaction. All clones were positive, including those determined to be negative by dot-blot tests, suggesting that mechanisms in addition to the presence of the etx gene can influence toxin production. The dot-blot test was efficient for the selection of toxigenic colonies of C. perfringens type D and demonstrated that homogeneous populations selected from toxigenic cultures produce higher titers of epsilon toxin. PMID:19779698

  12. Dissecting the Contributions of Clostridium perfringens Type C Toxins to Lethality in the Mouse Intravenous Injection Model

    PubMed Central

    Fisher, Derek J.; Fernandez-Miyakawa, Mariano E.; Sayeed, Sameera; Poon, Rachael; Adams, Victoria; Rood, Julian I.; Uzal, Francisco A.; McClane, Bruce A.

    2006-01-01

    The gram-positive anaerobe Clostridium perfringens produces a large arsenal of toxins that are responsible for histotoxic and enteric infections, including enterotoxemias, in humans and domestic animals. C. perfringens type C isolates, which cause rapidly fatal diseases in domestic animals and enteritis necroticans in humans, contain the genes for alpha toxin (plc), perfringolysin O (pfoA), beta toxin (cpb), and sometimes beta2 toxin (cpb2) and/or enterotoxin (cpe). Due to the economic impact of type C-induced diseases, domestic animals are commonly vaccinated with crude type C toxoid (prepared from inactivated culture supernatants) or bacterin/toxoid vaccines, and it is not clear which toxin(s) present in these vaccines actually elicits the protective immune response. To improve type C vaccines, it would be helpful to assess the contribution of each toxin present in type C supernatants to lethality. To address this issue, we surveyed a large collection of type C isolates to determine their toxin-producing abilities. When late-log-phase vegetative culture supernatants were analyzed by quantitative Western blotting or activity assays, most type C isolates produced at least three lethal toxins, alpha toxin, beta toxin, and perfringolysin O, and several isolates also produced beta2 toxin. In the mouse intravenous injection model, beta toxin was identified as the main lethal factor present in type C late-log-phase culture supernatants. This conclusion was based on monoclonal antibody neutralization studies and regression analyses in which the levels of alpha toxin, beta toxin, perfringolysin O, and beta2 toxin production were compared with lethality. Collectively, our results highlight the importance of beta toxin for type C-induced toxemia. PMID:16926413

  13. Estimation of Salivary Glucose and Glycogen Content in Exfoliated Buccal Mucosal Cells of Patients with Type II Diabetes Mellitus

    PubMed Central

    Gopinathan, Deepa Moothedathu; Sukumaran, Sunil

    2015-01-01

    Background Diabetes mellitus is a common metabolic disorder which shows an increasing incidence worldwide. Constant monitoring of blood glucose in diabetic patient is required which involves painful invasive techniques. Saliva is gaining acceptance as diagnostic tool for various systemic diseases which can be collected noninvasively and by individuals with limited training. Aim The aim of the present study was to analyse the possibility of using salivary glucose and glycogen content of buccal mucosal cells as a diagnostic marker in Type II Diabetes mellitus patients which can be considered as adjuvant diagnostic tool to the gold standards. Materials and Methods Sample consists of 30 study and 30 control groups. Saliva was collected by passive drool method.Intravenous blood samples were collected for glucose estimation. Exfoliated buccal mucosal cells were collected from apparently normal buccal mucosa, smeared on dry glass slide and stained with PAS. Blood and salivary glucose are estimated by Glucose Oxidase endpoint method. For Glycogen estimation, number of PAS positive cells in fifty unfolded cells was analysed. Results The results of the present study revealed a significant increase in the salivary glucose level and the number of PAS positive buccal mucosal cells in the diabetics than in the controls. The correlation between the fasting serum glucose and fasting salivary glucose and also that between fasting serum glucose and PAS positive cells was statistically significant. But the correlation between the staining intensity and fasting serum glucose was statistically insignificant. Conclusion With the results of the present study it is revealed that salivary glucose and PAS positive cells are increased in diabetics which can be considered as adjuvant diagnostic tool for Diabetes mellitus. PMID:26155572

  14. The Crystal Structure of Shiga Toxin Type 2 with Bound Disaccharide Guides the Design of a Heterobifunctional Toxin Inhibitor*

    PubMed Central

    Jacobson, Jared M.; Yin, Jiang; Kitov, Pavel I.; Mulvey, George; Griener, Tom P.; James, Michael N. G.; Armstrong, Glen; Bundle, David R.

    2014-01-01

    Shiga toxin type 2 (Stx2a) is clinically most closely associated with enterohemorrhagic E. coli O157:H7-mediated hemorrhagic colitis that sometimes progresses to hemolytic-uremic syndrome. The ability to express the toxin has been acquired by other Escherichia coli strains, and outbreaks of food poisoning have caused significant mortality rates as, for example, in the 2011 outbreak in northern Germany. Stx2a, an AB5 toxin, gains entry into human cells via the glycosphingolipid receptor Gb3. We have determined the first crystal structure of a disaccharide analog of Gb3 bound to the B5 pentamer of Stx2a holotoxin. In this Gb3 analog, α-GalNAc replaces the terminal α-Gal residue. This co-crystal structure confirms previous inferences that two of the primary binding sites identified in the B5 pentamer of Stx1 are also functional in Stx2a. This knowledge provides a rationale for the synthesis and evaluation of heterobifunctional antagonists for E. coli toxins that target Stx2a. Incorporation of GalNAc Gb3 trisaccharide in a heterobifunctional ligand with an attached pyruvate acetal, a ligand for human amyloid P component, and conjugation to poly[acrylamide-co-(3-azidopropylmethacrylamide)] produced a polymer that neutralized Stx2a in a mouse model of Shigatoxemia. PMID:24225957

  15. [Botulinum toxin type A in headache treatment : Established and experimental indications].

    PubMed

    Gaul, C; Holle-Lee, D; Straube, A

    2016-08-01

    In recent years botulinum toxin type A has been used increasingly more in the treatment of specific headache disorders. Especially regarding chronic migraine with and without combined medication overuse, convincing randomized studies have proven the efficacy of this treatment option and have led to approval for this indication. Regarding other headache entities, such as episodic migraine, tension-type headache, trigeminal autonomic cephalalgia (TAC), neuralgic, neuropathic and myofascial pain, currently available scientific data on the efficacy of botulinum toxin type A are scarce and often ambiguous. The exact underlying mechanisms of the influence of botulinum toxin type A on the pathophysiology of headache are not completely clear but an influence on the release of calcitonin gene-related peptide (CGRP) seems to play a crucial role. This article summarizes the most important studies as well as experiences of treatment with botulinum toxin type A regarding different headache entities. PMID:27300190

  16. Effects of botulinum toxin type D on secretion of tumor necrosis factor from human monocytes

    SciTech Connect

    Imamura, K.; Spriggs, D.; Ohno, T.; Kufe, D.

    1989-05-01

    Botulinum toxins are potent neurotoxins which block the release of neurotransmitters. The effects of these toxins on hematopoietic cells, however, are unknown. Monocytes secrete a variety of polypeptide growth factors, including tumor necrosis factor (TNF). In the study reported here, the effects of botulinum toxin type D on the secretion of TNF from human monocytes were examined. The results demonstrate that biotulinum toxin type D inhibits the release of TNF from monocytes activated by lipopolysaccharide (LPS) but not by 12-O-tetradecanoylphorbol-13-acetate. Botulinum toxin type D had no detectable effect on intracellular TNF levels in LPS-treated monocytes, indicating that the effects of this toxin involve the secretory process. This inhibitory effect of botulinum toxin type D on TNF secretion from LPS-treated monocytes was partially reversed by treatment with 12-O-tetradecanoylphorbol-13-acetate or introduction of guanosine 5'-(/gamma/-thio)t-riphosphate into these cells. The results demonstrate that TNF secretion is regulated by at least two distinct guanine nucleotide-binding proteins, one responsible for the activation of phospholiphase C and another which acts as a substrate for botulinum toxin type D. ADP-ribosylation of monocyte membranes by botulinum toxin type D demonstrated the presence of three substrates with M/sub r/s of 45,000, 21,000, and 17,000. While the role of these substrates in exocytosis is unknown, the results suggest that the M/sub r/ 21,000 substrate is involved in a process other than TNF secretion.

  17. Botulinum Toxin Type A (BOTOX) for Refractory Myofascial Pelvic Pain

    PubMed Central

    ADELOWO, Amos; HACKER, Michele R.; SHAPIRO, Alex; Modest, Anna Merport; ELKADRY, Eman

    2013-01-01

    Objective To assess intralevator Botulinum toxin type A (Botox) injections for refractory myofascial pelvic pain with short tight pelvic floor. Methods Retrospective cohort study of all women with intralevator Botox injection (100-300 Units) from 2005 through 2010 for refractory myofascial pelvic pain. Primary outcomes were self-reported pain on palpation and symptom improvement. Secondary outcomes included post-injection complications and repeat injection. Pain was assessed during digital palpation of the pelvic floor muscles using a scale of 0-10, with 10 being the worst possible pain. Follow-up occurred at <6 weeks post-injection and again at ≥ 6 weeks. Data are presented as median (interquartile range) or proportion. Results Thirty-one patients met eligibility criteria; 2 were lost to follow up and excluded. Median age was 55.0 years (38.0-62.0). Before Botox injection, median pain score was 9.5 (8.0-10.0). Twenty-nine patients (93.5%) returned for the first follow-up visit; 79.3% reported improvement in pain, while 20.7% reported no improvement. Median pain with levator palpation was significantly lower than before injection (P<0.0001). Eighteen women (58.0%) had a second follow-up visit with a median pain score that remained lower than before injection (P<0.0001). Fifteen (51.7%) women elected to have repeat Botox injection; the median time to repeat injection was 4.0 (3.0-7.0) months. Three (10.3%) women developed de-novo urinary retention, 2 (6.9%) reported fecal incontinence and 3 (10.3%) reported constipation and/or rectal pain; all side effects resolved spontaneously. Conclusions Intralevator injection of Botox demonstrates effectiveness in women with refractory myofascial pelvic pain with few, self-limiting adverse effects. PMID:23982578

  18. [Staphylococcal epidermal exfoliation (Ritter's disease)].

    PubMed

    Ruiz Maldonado, R; Tamayo, L; Vazquez, V; Dominguez, J

    1976-01-01

    According to the authors the best designation of Ritter's disease would be "staphilococcic epidermal exfoliation" SEE. The physiopathological and agnoslogical basis for this denomination could be the following: 1st The "S. aureus" is the ehtiological agent of the SSE in man. The Koch postulates necessary to confirm this hypothesis have been accomplished. 2nd "Staphylococcus aureus" produces a thermostable toxin that is active indepently of the staphilococcus and gives rise to the separation of the cells of the stratum granulosus of the epidermis and eventually exfoliation in suckling babies and in the newborn mouse. 3rd The "Staphylococcus aureus" may be present on the skin or in other localisations such as the bowel or pharinx. 4th The viable "S. aureus" when administered subcutaneously to the adult mice gives rise to lesions clinically and histologically similar to the impetigo observed in children. 5th The "S. aureus" killed by means of autoclave (that is, the staphylococcic toxine by itself does not give rise to any lesion when administered to the healthy adult mouse). Neijther has the SEE been observed in healthy adult man. The authors reach the conclusion that the SSE and the toxic epidermal necrolysis are basically different according to the histopathology therapeutic response and prognosis and they must be considered as independant entities. PMID:138775

  19. Type A and type B botulism in the North: first reported cases due to toxin other than type E in Alaskan Inuit.

    PubMed Central

    Barrett, D. H.; Eisenberg, M. S.; Bender, T. R.; Burks, J. M.; Hatheway, C. L.; Dowell, V. R.

    1977-01-01

    Botulism outbreaks shown to be due to type A and type B toxin occurred in Alaska, a region previously known for only type E botulism. The outbreak due to type A toxin involved three people, two of whom died. The outbreak due to type B toxin involved nine people, none of whom died. Both outbreaks were in Inuit villages, and native foods were incriminated. The occurrence of these outbreaks strongly suggests that Clostridium botulinum, types A and B are indigenous to Alaska. The outbreaks underscore the need for initial treatment of patients with antitoxin that is trivalent (ABE), even in Arctic regions. PMID:332309

  20. Resistance of ovine, caprine and bovine endothelial cells to Clostridium perfringens type D epsilon toxin in vitro.

    PubMed

    Uzal, F A; Rolfe, B E; Smith, N J; Thomas, A C; Kelly, W R

    1999-08-01

    Ovine, caprine and bovine endothelial cells were grown in vitro and challenged with Clostridium perfringens type D epsilon toxin to compare their susceptibility to this toxin. Madin Darby canine kidney (MDCK) cells, which are known to be susceptible to epsilon toxin, were used as a positive control. No morphological alterations were observed in any of the endothelial cell cultures tested, even after challenging with doses as high as 1200 MLD50/ml of epsilon toxin. MDCK cells showed contour rounding and nuclear condensation as early as 30 min after exposure to 100 MLD50/ml of epsilon toxin and after 60 min of exposure to 12.5 MLD50/ml of the same toxin. All the MDCK cells were dead after 3 h of exposure to all concentrations of epsilon toxin. The results indicate that ovine, caprine and bovine endothelial cells are not morphologically responsive to the action of epsilon toxin in vitro. PMID:10493114

  1. Pathogenesis of brain damage produced in sheep by Clostridium perfringens type D epsilon toxin: a review.

    PubMed

    Finnie, J W

    2003-04-01

    Microvascular endothelial damage by the epsilon toxin of Clostridium perfringens type D appears to be the fundamental cause of cerebral parenchymal injury and lesions occur in a seemingly dose- and time-dependent manner. Large doses of circulating toxin produce a severe, generalised, vasogenic cerebral oedema and an acute or peracute clinical course to death. With lower doses of toxin, or in partially immune sheep, focal necrosis, often bilaterally symmetrical, occurs in certain selectively vulnerable brain regions, which appear to become fewer as the toxin dose is reduced. These cases follow a more protracted clinical course, but death is the usual outcome. The precise pathogenesis of the focal brain damage found in subacutely intoxicated sheep is unresolved, but several possible mechanisms are discussed. PMID:15080445

  2. Botulinum toxin type A in the healing of chronic lesion following bilateral spasticity of gluteus muscle.

    PubMed

    Cigna, Emanuele; Maruccia, Michele; Fanelli, Benedetta; Scuderi, Nicolò

    2014-08-01

    Use of botulinum toxin is expanding as the clinical studies demonstrate new potential therapeutic applications. In rehabilitation, botulinum toxin is above all used as adjunct therapy for the treatment of spasticity, but it may prove useful for other atypical clinical situations. A 17-year-old man had a sub-arachnoid haemorrhage following the rupture of cerebral aneurism. The patient presented gluteus maximus and medius bilaterally spasticity that produced a chronic lesion in the intergluteal cleft, a flexed wrist and a flexed elbow. As treatment for this spasticity, a total of 100 U botulinum toxin type A were injected into the glutei muscles. This treatment allowed for application of topical medication and subsequently, chronic lesion healing. Botulinum toxin A may be an important therapeutic aid for clinicians faced with treating persistent pathological conditions caused by spasticity. PMID:23078619

  3. Patient considerations in the treatment of cervical dystonia: focus on botulinum toxin type A

    PubMed Central

    Mills, Reversa R; Pagan, Fernando L

    2015-01-01

    Cervical dystonia is the most common form of focal dystonia characterized by involuntary muscle contractions causing abnormal movements and posturing of the head and neck and is associated with significant pain. Botulinum toxin is considered first-line therapy in the treatment of pain and abnormal head posturing associated with cervical dystonia. There are currently three botulinum toxin type A neurotoxins and one botulinum type B neurotoxin commercially available and US Food and Drug Administration (FDA) labeled for the treatment of cervical dystonia. This review will focus on the efficacy, safety, and therapeutic use of botulinum type A neurotoxins in the treatment of cervical dystonia. We conclude with a discussion of factors influencing toxin selection including therapeutic effect, duration of effect, side effect profile, cost, and physician preference. PMID:26082621

  4. Prediction of Type II Toxin-Antitoxin Loci in Klebsiella pneumoniae Genome Sequences.

    PubMed

    Wei, Yi-Qing; Bi, De-Xi; Wei, Dong-Qing; Ou, Hong-Yu

    2016-06-01

    Klebsiella pneumoniae is an increasingly important bacterial pathogen to human. This Gram-negative bacterium species has become a serious concern due to its dramatic increase in the levels of multiple antibiotic resistances, particularly to carbapenems. The toxin-antitoxin (TA) system has recently been reported to be involved in the formation of drug-tolerant persister cells. The type II TA system is composed of a stable toxin protein and a relatively unstable antitoxin protein that is able to inhibit the toxin. Here, we examine the type II TA locus distribution and compare the TA diversity throughout ten completely sequenced K. pneumoniae genomes by using bioinformatics approaches. Two hundred and twelve putative type II TA loci were identified in 30 replicons of these K. pneumoniae strains. The amino acid sequence similarity-based grouping shows that these loci distribute differently not only among different K. pneumoniae strains isolated from diverse sources, but also between their chromosomes and plasmids. PMID:26662948

  5. Thermally exfoliated graphite oxide

    NASA Technical Reports Server (NTRS)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

  6. Pharmacological study on angusticeps-type toxins from mamba snake venoms.

    PubMed

    Lee, C Y; Tsai, M C; Tsaur, M L; Lin, W W; Carlsson, F H; Joubert, F J

    1985-05-01

    Five angusticeps-type toxins, F7, F8 and C10S2C2 from Dendroaspis angusticeps and C and FS2 from D. polylepis polylepis, were tested for action on the chick biventer cervicis nerve-muscle, the frog rectus abdominis muscle and the mouse phrenic nerve-diaphragm preparations. In the chick muscle, none of these toxins exhibited any stimulatory effect up to 100 micrograms/ml. In the frog muscle, the response to acetylcholine, but not to carbachol, was enhanced dose dependently by F7 and C. No appreciable effect was observed with the other three toxins. In the mouse diaphragm, also only F7 and C augmented responses to indirect stimulation and produced spontaneous fasciculations. On tetanic stimulation, a marked Wedensky inhibition was observed. Their stimulatory effect was abolished by d-tubocurarine. In the presence of d-tubocurarine as well as in the denervated mouse diaphragm, neither toxin increased responses to direct stimulation. In low-calcium (0.6 mM) or high magnesium (4.2 mM) medium, the stimulatory effect of both toxins was markedly attenuated. The resting membrane potential of the mouse diaphragm was not changed. The amplitude and frequency of MEPPs and the quantal content and the half-decay time of EPPs was increased. Both toxins also produced a stimulatory effect on the isolated guinea-pig ileum, which was abolished by atropine. In the rat atrial preparation, both toxins caused negative inotropic and chronotropic effects, which were reversed by atropine. If pretreated with atropine, these effects were completely prevented. Both F7 and C markedly inhibited the cholinesterase activity of the homogenized mouse diaphragm and frog rectus abdominis muscle but not that of the chick biventer cervicis muscle.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3158733

  7. In situ detection of the Clostridium botulinum type C1 toxin gene in wetland sediments with a nested PCR assay

    USGS Publications Warehouse

    Williamson, J.L.; Rocke, T.E.; Aiken, Judd M.

    1999-01-01

    A nested PCR was developed for detection of the Clostridium botulinum type C1 toxin gene in sediments collected from wetlands where avian botulism outbreaks had or had not occurred. The C1 toxin gene was detected in 16 of 18 sites, demonstrating both the ubiquitous distribution of C. botulinum type C in wetland sediments and the sensitivity of the detection assay.

  8. Botulinum toxin type A treatment to the upper face: retrospective analysis of daily practice

    PubMed Central

    Prager, Welf; Huber-Vorländer, Jürgen; Taufig, A Ziah; Imhof, Matthias; Kühne, Ulrich; Weissberg, Ruth; Kuhr, Lars-Peter; Rippmann, Volker; Philipp-Dormston, Wolfgang G; Proebstle, Thomas M; Roth, Claudia; Kerscher, Martina; Ulmann, Claudius; Pavicic, Tatjana

    2012-01-01

    Background Botulinum toxin type A treatment has been used for over 20 years to enhance the appearance of the face. There are several commercially available botulinum toxin type A products used in aesthetic clinical practice. The aim of this retrospective analysis was to compare the clinical efficacy of the most commonly used botulinum toxin type A preparations in daily practice. Methods Physicians from 21 centers in Germany completed questionnaires based on an inspection of subject files for subjects 18 years of age or over who had received at least two, but not more than three, consecutive treatments with incobotulinumtoxinA, onabotulinumtoxinA, or abobotulinumtoxinA within a 12-month period in the previous 2 years. Data on subject and physician satisfaction, treatment intervals, dosages, and safety were collected from 1256 subjects. Results There were no statistically significant differences between incobotulinumtoxinA and onabotulinumtoxinA with respect to physician and subject satisfaction, dosages, and adverse effects experienced. Both botulinum toxin type A preparations were well tolerated and effective in the treatment of upper facial lines. Due to low treatment numbers, abobotulinumtoxinA was not included in the statistical analysis. Conclusion The results of this retrospective analysis confirm the results of prospective clinical trials by demonstrating that, in daily practice, incobotulinumtoxinA and onabotulinumtoxinA are used at a 1:1 dose ratio and display comparable efficacy and safety. PMID:22791996

  9. Detection of botulinum toxin types A, B, E, and F activity using the quail embryo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently demonstrated an effective new model for the detection of botulinum toxin type A using quail embryos in place of the mouse model. These experiments demonstrated that the Japanese quail embryo at 15 days of incubation was an effective vertebrate animal model to detect the activity of botu...

  10. Elevation of the Corner of the Mouth Using Botulinum Toxin Type A

    PubMed Central

    Goldman, Alberto; Wollina, Uwe

    2010-01-01

    Indications for botulinum toxin type A have been constantly evolving, and it can currently be used in virtually any area of the face and neck. The authors present their experience with this neurotoxin in treating the platysmal bands and depressor anguli oris muscle with the purpose of cosmetically improving the anterior neck and lifting the oral commissure. PMID:21430826

  11. Evaluation of emm gene types, toxin gene profiles and clonal relatedness of group A streptococci

    PubMed Central

    Mengeloglu, Firat Zafer; Aktas, Elif; Otlu, Baris; Cömert, Füsun; Külah, Canan; Tas, Ebru; Sümbüloglu, Vildan

    2013-01-01

    The aim of this study is to evaluate antibiotic susceptibilities, emm gene types, toxin gene profiles and clonal relatedness of group A streptococci (GAS) isolates obtained from patients and carriers. A total of 79 clinical isolates from patients and 60 isolates from carriers were included in the study. Emm typing, toxin gene detection for speA, speB, speC, speG and smeZ genes and pulsed-field gel electrophoresis (PFGE) was performed. Twenty-one distinct emm types were detected; the most common types were emm12, emm89, emm 1, emm77, emm4 and emm3. The detection rates of both emm types and the toxin genes didn’t differ significantly between patients and carriers. The presence of speA and smeZ was significantly higher in emm1 and speG was significantly lower in emm4 when compared to the other emm types. The rate of clustering obtained with PFGE wasn’t significantly different in patients and carriers. As a result, twelve of the 21 emm types detected in this study were covered by the 26-valent vaccine, constituting 77.7% of the emm typeable isolates; however the emm4 type which is one of the most common types in the present study is not among this coverage. PMID:23988167

  12. Keeping the Wolves at Bay: Antitoxins of Prokaryotic Type II Toxin-Antitoxin Systems

    PubMed Central

    Chan, Wai Ting; Espinosa, Manuel; Yeo, Chew Chieng

    2016-01-01

    In their initial stages of discovery, prokaryotic toxin-antitoxin (TA) systems were confined to bacterial plasmids where they function to mediate the maintenance and stability of usually low- to medium-copy number plasmids through the post-segregational killing of any plasmid-free daughter cells that developed. Their eventual discovery as nearly ubiquitous and repetitive elements in bacterial chromosomes led to a wealth of knowledge and scientific debate as to their diversity and functionality in the prokaryotic lifestyle. Currently categorized into six different types designated types I–VI, type II TA systems are the best characterized. These generally comprised of two genes encoding a proteic toxin and its corresponding proteic antitoxin, respectively. Under normal growth conditions, the stable toxin is prevented from exerting its lethal effect through tight binding with the less stable antitoxin partner, forming a non-lethal TA protein complex. Besides binding with its cognate toxin, the antitoxin also plays a role in regulating the expression of the type II TA operon by binding to the operator site, thereby repressing transcription from the TA promoter. In most cases, full repression is observed in the presence of the TA complex as binding of the toxin enhances the DNA binding capability of the antitoxin. TA systems have been implicated in a gamut of prokaryotic cellular functions such as being mediators of programmed cell death as well as persistence or dormancy, biofilm formation, as defensive weapons against bacteriophage infections and as virulence factors in pathogenic bacteria. It is thus apparent that these antitoxins, as DNA-binding proteins, play an essential role in modulating the prokaryotic lifestyle whilst at the same time preventing the lethal action of the toxins under normal growth conditions, i.e., keeping the proverbial wolves at bay. In this review, we will cover the diversity and characteristics of various type II TA antitoxins. We shall

  13. Keeping the Wolves at Bay: Antitoxins of Prokaryotic Type II Toxin-Antitoxin Systems.

    PubMed

    Chan, Wai Ting; Espinosa, Manuel; Yeo, Chew Chieng

    2016-01-01

    In their initial stages of discovery, prokaryotic toxin-antitoxin (TA) systems were confined to bacterial plasmids where they function to mediate the maintenance and stability of usually low- to medium-copy number plasmids through the post-segregational killing of any plasmid-free daughter cells that developed. Their eventual discovery as nearly ubiquitous and repetitive elements in bacterial chromosomes led to a wealth of knowledge and scientific debate as to their diversity and functionality in the prokaryotic lifestyle. Currently categorized into six different types designated types I-VI, type II TA systems are the best characterized. These generally comprised of two genes encoding a proteic toxin and its corresponding proteic antitoxin, respectively. Under normal growth conditions, the stable toxin is prevented from exerting its lethal effect through tight binding with the less stable antitoxin partner, forming a non-lethal TA protein complex. Besides binding with its cognate toxin, the antitoxin also plays a role in regulating the expression of the type II TA operon by binding to the operator site, thereby repressing transcription from the TA promoter. In most cases, full repression is observed in the presence of the TA complex as binding of the toxin enhances the DNA binding capability of the antitoxin. TA systems have been implicated in a gamut of prokaryotic cellular functions such as being mediators of programmed cell death as well as persistence or dormancy, biofilm formation, as defensive weapons against bacteriophage infections and as virulence factors in pathogenic bacteria. It is thus apparent that these antitoxins, as DNA-binding proteins, play an essential role in modulating the prokaryotic lifestyle whilst at the same time preventing the lethal action of the toxins under normal growth conditions, i.e., keeping the proverbial wolves at bay. In this review, we will cover the diversity and characteristics of various type II TA antitoxins. We shall

  14. The early effects of Clostridium perfringens type D epsilon toxin in ligated intestinal loops of goats and sheep.

    PubMed

    Fernandez Miyakawa, M E; Uzal, F A

    2003-04-01

    Clostridium perfringens type D produces enterotoxaemia in goats, sheep and other animals. The disease is caused by C. perfringens epsilon toxin and, while enterotoxaemia in goats is usually characterized by enterocolitis, the disease in sheep is characterized by systemic lesions (such as lung and brain oedema) with minor and inconsistent changes observed in the intestine. A possible explanation for these differences is that epsilon toxin is more promptly absorbed by the ovine than by the caprine intestine. In an attempt to clarify this, we examined the early effects of epsilon toxin on caprine and ovine intestine. Intestinal loop assays were performed to analyse the physiological and morphological changes induced by epsilon toxin in the intestine of these species. Fluid accumulation was observed in caprine and ovine ileum and colon treated with epsilon toxin. Ileal loops from goats treated with epsilon toxin retained sodium and water earlier than ovine ileal loops treated with the same toxin. Histological analysis showed morphological alterations in the colon of both species as early as 2 h after the commencement of epsilon toxin treatment: these changes were more marked in goats than in sheep. No morphological changes were observed in the ileum of either species after 4 h incubation with epsilon toxin. These results suggest that epsilon toxin modifies ion and water transport in the small and the large intestine of goats and sheep through different mechanisms. PMID:12777097

  15. Type II Toxin-Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803.

    PubMed

    Kopfmann, Stefan; Roesch, Stefanie K; Hess, Wolfgang R

    2016-01-01

    Bacterial toxin-antitoxin (TA) systems are genetic elements, which are encoded by plasmid as well as chromosomal loci. They mediate plasmid and genomic island maintenance through post-segregational killing mechanisms but may also have milder effects, acting as mobile stress response systems that help certain cells of a population in persisting adverse growth conditions. Very few cyanobacterial TA system have been characterized thus far. In this work, we focus on the cyanobacterium Synechocystis 6803, a widely used model organism. We expand the number of putative Type II TA systems from 36 to 69 plus seven stand-alone components. Forty-seven TA pairs are located on the chromosome and 22 are plasmid-located. Different types of toxins are associated with various antitoxins in a mix and match principle. According to protein domains and experimental data, 81% of all toxins in Synechocystis 6803 likely exhibit RNase activity, suggesting extensive potential for toxicity-related RNA degradation and toxin-mediated transcriptome remodeling. Of particular interest is the Ssr8013-Slr8014 system encoded on plasmid pSYSG, which is part of a larger defense island or the pSYSX system Slr6056-Slr6057, which is linked to a bacterial ubiquitin-like system. Consequently, Synechocystis 6803 is one of the most prolific sources of new information about these genetic elements. PMID:27455323

  16. Botulinum toxin type B vs. type A in toxin-naïve patients with cervical dystonia: Randomized, double-blind, noninferiority trial.

    PubMed

    Pappert, Eric J; Germanson, Terry

    2008-03-15

    The objective of this study was to compare efficacy, safety, and duration of botulinum toxin type A (BoNT-A) and type B (BoNT-B) in toxin-naïve cervical dystonia (CD) subjects. BoNT-naïve CD subjects were randomized to BoNT-A or BoNT-B and evaluated in a double-blind trial at baseline and every 4-weeks following one treatment. The primary measure was the change in Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) from baseline to week 4 post-injection. Secondary measures included change in TWSTRS-subscale scores, pain, global impressions, and duration of response and safety assessments. The study was designed as a noninferiority trial of BoNT-B to BoNT-A. 111 subjects were randomized (55 BoNT-A; 56 BoNT-B). Improvement in TWSTRS-total scores 4 weeks after BoNT-B was noninferior to BoNT-A (adjusted means 11.0 (SE 1.2) and 8.8 (SE 1.2), respectively; per-protocol-population (PPP)). The median duration of effect of BoNT-A and BoNT-B was not different (13.1 vs. 13.7 weeks, respectively; P-value = 0.833; PPP). There were no significant differences in the occurrence of injection site pain and dysphagia. Mild dry mouth was more frequent with BoNT-B but there were no differences for moderate/severe dry mouth. In this study, both BoNT-A and B were shown to be effective and safe for the treatment of toxin-naive CD subjects. PMID:18098274

  17. Scorpion toxins that block T-type Ca2+ channels in spermatogenic cells inhibit the sperm acrosome reaction.

    PubMed

    López-González, Ignacio; Olamendi-Portugal, Timoteo; De la Vega-Beltrán, José L; Van der Walt, Jurg; Dyason, Karin; Possani, Lourival D; Felix, Ricardo; Darszon, Alberto

    2003-01-10

    The acrosome reaction (AR) is a Ca(2+)-dependent event required for sperm to fertilize the egg. The activation of T-type voltage-gated Ca(2+) channels plays a key role in the induction of this process. This report describes the actions of two toxins from the scorpion Parabuthus granulatus named kurtoxin-like I and II (KLI and KLII, respectively) on sperm Ca(2+) channels. Both toxins decrease T-type Ca(2+) channel activity in mouse spermatogenic cells and inhibit the AR in mature sperm. Saturating concentrations of the toxins inhibited at most approximately 70% of the whole-cell Ca(2+) current, suggesting the presence of a toxin-resistant component. In addition, both toxins inhibited approximately 60% of the AR, which is consistent with the participation of T-type Ca(2+) channels in the sperm AR. PMID:12504099

  18. Contact with enterocyte-like Caco-2 cells induces rapid upregulation of toxin production by Clostridium perfringens type C isolates

    PubMed Central

    Vidal, Jorge E.; Ohtani, Kaori; Shimizu, Tohru; McClane, Bruce A.

    2009-01-01

    Clostridium perfringens type C isolates cause necrotizing enteritis in humans and domestic animals. In vitro, type C isolates often produce beta toxin (CPB), beta2 toxin (CPB2), alpha toxin (CPA), perfringolysin O (PFO), and TpeL during (or after) late log-phase growth. In contrast, the current study found that many type C isolates respond to close contact with enterocyte-like Caco-2 cells by producing all toxins, except TpeL, much more rapidly than occurs during in vitro growth. This in vivo effect involves rapid transcriptional upregulation of the cpb, cpb2, pfoA and plc toxin genes. Rapid Caco-2 cell-induced upregulation of CPB and PFO production involves the VirS/VirR two-component system, since upregulated in vivo transcription of the pfoA and cpb genes was blocked by inactivating the virR gene and was reversible by complementation to restore VirR expression. However, the luxS quorum sensing system is not required for the rapid upregulation of type C toxin production induced by contact with Caco-2 cells. These results provide the first indication of host cell:pathogen cross-talk affecting toxin production kinetics by any pathogenic Clostridium spp., identify in vivo vs. in vitro differences in C. perfringens toxin expression, and implicate VirS/VirR as a possible contributor to some C. perfringens enteric diseases. PMID:19438515

  19. Use of botulinum toxin type A in the management of patients with neurological disorders: a national survey

    PubMed Central

    Smania, Nicola; Colosimo, Carlo; Bentivoglio, Anna Rita; Sandrini, Giorgio; Picelli, Alessandro

    2013-01-01

    Summary The aim of this survey was to provide an overview of important issues relating to therapeutic strategies based on botulinum toxin type A injection for the treatment of patients with neurological disorders. Two hundred and ten physicians from neurology and neurorehabilitation units in Italian hospitals answered a questionnaire exploring some clinical aspects of the use of botulinum toxin type A in patients with spasticity/dystonia. 66% of the physicians treated patients with dystonia, 80% treated adults with spasticity, and 35% treated children with cerebral palsy. Palpation with no instrumental guidance was the injection technique most commonly used for treating patients with dystonia, spasticity and cerebral palsy; 57% of the physicians evaluated patients instrumentally before toxin injection, while 45% assessed post-injection improvements by instrumental means; 78% of the physicians prescribed (when appropriate) rehabilitation procedures after toxin injection. Our results seem to show that the routine use of botulinum toxin in clinics is far from standardized. PMID:24598392

  20. Clostridium perfringens type A toxin production in 3 commonly used culture media.

    PubMed

    Fernandez-Miyakawa, Mariano E; Marcellino, Romanella; Uzal, Francisco A

    2007-03-01

    In vitro toxin production is an important tool not only for diagnostic purposes but also for the study of pathogenesis of Clostridium perfringens infections. The present study was carried out to compare the level of toxin production by several strains of C. perfringens type A, isolated from the intestine of animals, when cultured in 3 different conventional culture media. Six strains of C. perfringens type A isolated from the small intestine of healthy sheep were cultured in commercial cooked meat medium (CMM), brain heart infusion (BHI), and tryptone glucose yeast (TGY). Intravenous lethality in mice and phospholipase C (PLC) activity were measured in filtered culture supernatants. Lethality of culture supernatants was highest for all isolates when grown in BHI, followed by CMM. No supernatants from any isolates grown in TGY produced lethality in mice. Phospholipase C activity was highest when the isolates were grown in BHI and CMM and significantly lower when grown in TGY. PMID:17402614

  1. The Role of Botulinum Toxin Type A in the Clinical Management of Refractory Anterior Knee Pain

    PubMed Central

    Singer, Barbara J.; Silbert, Benjamin I.; Silbert, Peter L.; Singer, Kevin P.

    2015-01-01

    Anterior knee pain is a highly prevalent condition affecting largely young to middle aged adults. Symptoms can recur in more than two thirds of cases, often resulting in activity limitation and reduced participation in employment and recreational pursuits. Persistent anterior knee pain is difficult to treat and many individuals eventually consider a surgical intervention. Evidence for long term benefit of most conservative treatments or surgical approaches is currently lacking. Injection of Botulinum toxin type A to the distal region of vastus lateralis muscle causes a short term functional “denervation” which moderates the influence of vastus lateralis muscle on the knee extensor mechanism and increases the relative contribution of the vastus medialis muscle. Initial data suggest that, compared with other interventions for anterior knee pain, Botulinum toxin type A injection, in combination with an active exercise programme, can lead to sustained relief of symptoms, reduced health care utilisation and increased activity participation. The procedure is less invasive than surgical intervention, relatively easy to perform, and is time- and cost-effective. Further studies, including larger randomized placebo-controlled trials, are required to confirm the effectiveness of Botulinum toxin type A injection for anterior knee pain and to elaborate the possible mechanisms underpinning pain and symptom relief. PMID:26308056

  2. A new type V toxin-antitoxin system where mRNA for toxin GhoT is cleaved by antitoxin GhoS.

    PubMed

    Wang, Xiaoxue; Lord, Dana M; Cheng, Hsin-Yao; Osbourne, Devon O; Hong, Seok Hoon; Sanchez-Torres, Viviana; Quiroga, Cecilia; Zheng, Kevin; Herrmann, Torsten; Peti, Wolfgang; Benedik, Michael J; Page, Rebecca; Wood, Thomas K

    2012-10-01

    Among bacterial toxin-antitoxin systems, to date no antitoxin has been identified that functions by cleaving toxin mRNA. Here we show that YjdO (renamed GhoT) is a membrane lytic peptide that causes ghost cell formation (lysed cells with damaged membranes) and increases persistence (persister cells are tolerant to antibiotics without undergoing genetic change). GhoT is part of a new toxin-antitoxin system with YjdK (renamed GhoS) because in vitro RNA degradation studies, quantitative real-time reverse-transcription PCR and whole-transcriptome studies revealed that GhoS masks GhoT toxicity by cleaving specifically yjdO (ghoT) mRNA. Alanine substitutions showed that Arg28 is important for GhoS activity, and RNA sequencing indicated that the GhoS cleavage site is rich in U and A. The NMR structure of GhoS indicates it is related to the CRISPR-associated-2 RNase, and GhoS is a monomer. Hence, GhoT-GhoS is to our knowledge the first type V toxin-antitoxin system where a protein antitoxin inhibits the toxin by cleaving specifically its mRNA. PMID:22941047

  3. Evaluation of different fluids for detection of Clostridium perfringens type D epsilon toxin in sheep with experimental enterotoxemia.

    PubMed

    Layana, Jorge E; Fernandez Miyakawa, Mariano E; Uzal, Francisco A

    2006-08-01

    Enterotoxemia caused by Clostridium perfringens type D is a highly lethal disease of sheep, goats and other ruminants. The diagnosis of this condition is usually confirmed by detection of epsilon toxin, a major exotoxin produced by C. perfringens types B and D, in the intestinal content of affected animals. It has been suggested that other body fluids can also be used for detection of epsilon toxin. This study was performed to evaluate the usefulness of intestinal content versus other body fluids in detecting epsilon toxin in cases of sheep enterotoxemia. Samples of duodenal, ileal and colon contents, pericardial and abdominal fluids, aqueous humor and urine from 15 sheep with experimentally induced enterotoxemia, were analysed for epsilon toxin using a capture ELISA. Epsilon toxin was detected in 92% of the samples of ileal content, 64% of the samples of duodenal content, 57% of the samples of colon content and in 7% of the samples of pericardial fluid and aqueous humor. No epsilon toxin was found in samples of abdominal fluid or urine from the animals with enterotoxemia or in any samples from six clinically healthy sheep used as negative controls. The results of this study indicate that with the diagnostic capture ELISA used, intestinal content (preferably ileum) should be used for C. perfringens type D epsilon toxin detection in suspected cases of sheep enterotoxemia. PMID:16857397

  4. Factors affecting growth and toxin production by Clostridium botulinum type E on irradiated (0. 3 Mrad) chicken skins

    SciTech Connect

    Firstenberg-Eden, R.; Rowley, D.B.; Shattuck, G.E.

    1982-05-01

    A model system (chicken skins with chicken exudate) was used to determine if Clostridium botulinum type E (Beluga) spores, stressed by low dose irradiation, would develop and produce toxin at abuse temperatures of 10 and 30/sup 0/C in the absence of characteristic spoilage. Unstressed spores germinated, multiplied, and produced toxin on vacuum-packed chicken skins, stored at either 30 or 10/sup 0/C. Cell numbers increased faster and toxin was evident sooner at 30/sup 0/C than at 10/sup 0/C. At 30/sup 0/C, growth occurred and toxin was produced more slowly when samples were incubated aerobically than anaerobically. When samples were incubated aerobically at 10/sup 0/C, no toxin was detected within a test period of 14 days. An irradiation dose of 0.3 Mrad at 5/sup 0/C reduced a spore population on vacuum-sealed chicken skins by about 90%. The surviving population produced toxin at 30/sup 0/C under either aerobic or anaerobic conditions, at 10/sup 0/C no toxin was detected even on skins incubated anaerobically. Under the worst conditions (30/sup 0/C, vacuum packed) toxin was not detected prior to characteristic spoilage caused by the natural flora surviving 0.3 Mrad.

  5. Type II Toxin-Antitoxin Distribution and Adaptive Aspects on Xanthomonas Genomes: Focus on Xanthomonas citri.

    PubMed

    Martins, Paula M M; Machado, Marcos A; Silva, Nicholas V; Takita, Marco A; de Souza, Alessandra A

    2016-01-01

    Prokaryotic toxin-antitoxin (TA) systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of 10 Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB, and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB) was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes. PMID:27242687

  6. Type II Toxin-Antitoxin Distribution and Adaptive Aspects on Xanthomonas Genomes: Focus on Xanthomonas citri

    PubMed Central

    Martins, Paula M. M.; Machado, Marcos A.; Silva, Nicholas V.; Takita, Marco A.; de Souza, Alessandra A.

    2016-01-01

    Prokaryotic toxin-antitoxin (TA) systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of 10 Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB, and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB) was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes. PMID:27242687

  7. Molecular cloning and expression of epsilon toxin from Clostridium perfringens type D and tests of animal immunization.

    PubMed

    Souza, A M; Reis, J K P; Assis, R A; Horta, C C; Siqueira, F F; Facchin, S; Alvarenga, E R; Castro, C S; Salvarani, F M; Silva, R O S; Pires, P S; Contigli, C; Lobato, F C F; Kalapothakis, E

    2010-01-01

    Epsilon toxin produced by Clostridium perfringens types B and D causes enterotoxemia in sheep, goats and calves. Enterotoxemia can cause acute or superacute disease, with sudden death of the affected animal. It provokes huge economic losses when large numbers of livestock are affected. Therapeutic intervention is challenging, because the disease progresses very rapidly. However, it can be prevented by immunization with specific immunogenic vaccines. We cloned the etx gene, encoding epsilon toxin, into vector pET-11a; recombinant epsilon toxin (rec-epsilon) was expressed in inclusion bodies and was used for animal immunization. Serum protection was evaluated and cross-serum neutralization tests were used to characterize the recombinant toxin. To analyze the potency of the toxin (as an antigen), rabbits were immunized with 50, 100 or 200 microg recombinant toxin, using aluminum hydroxide gel as an adjuvant. Titers of 10, 30 and 40 IU/mL were obtained, respectively. These titers were higher than the minimum level required by the European Pharmacopoeia (5 IU/mL) and by the USA Code of Federal Regulation (2 IU/mL). This rec-epsilon is a good candidate for vaccine production against enterotoxemia caused by epsilon toxin of C. perfringens type D. PMID:20198582

  8. Live Attenuated Shigella dysenteriae Type 1 Vaccine Strains Overexpressing Shiga Toxin B Subunit ▿

    PubMed Central

    Wu, Tao; Grassel, Christen; Levine, Myron M.; Barry, Eileen M.

    2011-01-01

    Shigella dysenteriae serotype 1 (S. dysenteriae 1) is unique among the Shigella species and serotypes in the expression of Shiga toxin which contributes to more severe disease sequelae and the ability to cause explosive outbreaks and pandemics. S. dysenteriae 1 shares characteristics with other Shigella species, including the capability of causing clinical illness with a very low inoculum (10 to 100 CFU) and resistance to multiple antibiotics, underscoring the need for efficacious vaccines and therapeutics. Following the demonstration of the successful attenuating capacity of deletion mutations in the guaBA operon in S. flexneri 2a vaccine strains in clinical studies, we developed a series of S. dysenteriae 1 vaccine candidates containing the fundamental attenuating mutation in guaBA. All strains are devoid of Shiga toxin activity by specific deletion of the gene encoding the StxA subunit, which encodes enzymatic activity. The StxB subunit was overexpressed in several derivatives by either plasmid-based constructs or chromosomal manipulation to include a strong promoter. All strains are attenuated for growth in vitro in the HeLa cell assay and for plaque formation and were safe in the Serény test and immunogenic in the guinea pigs. Each strain induced robust serum and mucosal anti-S. dysenteriae 1 lipopolysaccharide (LPS) responses and protected against wild-type challenge. Two strains engineered to overexpress StxB induced high titers of Shiga toxin neutralizing antibodies. These candidates demonstrate the potential for a live attenuated vaccine to protect against disease caused by S. dysenteriae 1 and potentially to protect against the toxic effects of other Shiga toxin 1-expressing pathogens. PMID:21969003

  9. Management of exfoliative glaucoma: challenges and solutions

    PubMed Central

    Holló, Gábor; Katsanos, Andreas; Konstas, Anastasios GP

    2015-01-01

    Exfoliative glaucoma is the most common type of secondary open-angle glaucoma worldwide. It is characterized by high intraocular pressure (IOP) and worse 24-hour IOP characteristics. In order to minimize progression, treatment of exfoliative glaucoma has to provide a low long-term mean IOP and good 24-hour IOP control. To achieve these goals, fixed-dose combination eye drops, argon and selective laser trabeculoplasty, and various forms of surgery (trabeculectomy, deep sclerectomy, viscocanalostomy, ab interno trabeculotomy, trabecular aspiration, and cataract surgery) all need to be considered during the long-term management of the disease. Since exfoliative glaucoma is a disease of the elderly, and is frequently associated with systemic vascular disease, interdisciplinary consultations are of great clinical importance. These management aspects and the current medical, laser, and surgical results are covered in this review, with a special focus on the needs of the general ophthalmologist. PMID:26045655

  10. Management of exfoliative glaucoma: challenges and solutions.

    PubMed

    Holló, Gábor; Katsanos, Andreas; Konstas, Anastasios Gp

    2015-01-01

    Exfoliative glaucoma is the most common type of secondary open-angle glaucoma worldwide. It is characterized by high intraocular pressure (IOP) and worse 24-hour IOP characteristics. In order to minimize progression, treatment of exfoliative glaucoma has to provide a low long-term mean IOP and good 24-hour IOP control. To achieve these goals, fixed-dose combination eye drops, argon and selective laser trabeculoplasty, and various forms of surgery (trabeculectomy, deep sclerectomy, viscocanalostomy, ab interno trabeculotomy, trabecular aspiration, and cataract surgery) all need to be considered during the long-term management of the disease. Since exfoliative glaucoma is a disease of the elderly, and is frequently associated with systemic vascular disease, interdisciplinary consultations are of great clinical importance. These management aspects and the current medical, laser, and surgical results are covered in this review, with a special focus on the needs of the general ophthalmologist. PMID:26045655

  11. Discovery of a Distinct Superfamily of Kunitz-Type Toxin (KTT) from Tarantulas

    PubMed Central

    Diao, Jian-Bo; Jiang, Li-Ping; Tang, Xing; Liang, Song-Ping

    2008-01-01

    Background Kuntiz-type toxins (KTTs) have been found in the venom of animals such as snake, cone snail and sea anemone. The main ancestral function of Kunitz-type proteins was the inhibition of a diverse array of serine proteases, while toxic activities (such as ion-channel blocking) were developed under a variety of Darwinian selection pressures. How new functions were grafted onto an old protein scaffold and what effect Darwinian selection pressures had on KTT evolution remains a puzzle. Principal Findings Here we report the presence of a new superfamily of KTTs in spiders (Tarantulas: Ornithoctonus huwena and Ornithoctonus hainana), which share low sequence similarity to known KTTs and is clustered in a distinct clade in the phylogenetic tree of KTT evolution. The representative molecule of spider KTTs, HWTX-XI, purified from the venom of O. huwena, is a bi-functional protein which is a very potent trypsin inhibitor (about 30-fold more strong than BPTI) as well as a weak Kv1.1 potassium channel blocker. Structural analysis of HWTX-XI in 3-D by NMR together with comparative function analysis of 18 expressed mutants of this toxin revealed two separate sites, corresponding to these two activities, located on the two ends of the cone-shape molecule of HWTX-XI. Comparison of non-synonymous/synonymous mutation ratios (ω) for each site in spider and snake KTTs, as well as PBTI like body Kunitz proteins revealed high Darwinian selection pressure on the binding sites for Kv channels and serine proteases in snake, while only on the proteases in spider and none detected in body proteins, suggesting different rates and patterns of evolution among them. The results also revealed a series of key events in the history of spider KTT evolution, including the formation of a novel KTT family (named sub-Kuntiz-type toxins) derived from the ancestral native KTTs with the loss of the second disulfide bridge accompanied by several dramatic sequence modifications. Conclusions

  12. Role of Botulinum Toxin Type-A (BTX-A) in the Management of Trigeminal Neuralgia

    PubMed Central

    2013-01-01

    Trigeminal neuralgia (TN) is a clinical condition characterized by paroxysmal attacks of severe and electric shock-like pain along the distribution of one or more branches of the trigeminal nerve. Various medicinal or surgical modalities have been employed in the past with variable success. Newer methods were tried in search of permanent cure or long-lasting pain relief. The purpose of this paper is to present the review of the literature regarding the use of botulinum toxin type-A (BTX-A) in the management of trigeminal neuralgia. PMID:24194982

  13. Monoclonal antibody-based immunoassay for type A Clostridium botulinum toxin is comparable to the mouse bioassay.

    PubMed Central

    Shone, C; Wilton-Smith, P; Appleton, N; Hambleton, P; Modi, N; Gatley, S; Melling, J

    1985-01-01

    A monoclonal antibody (BA11) has been produced against Clostridium botulinum type A neurotoxin by the fusion of myeloma cells (P3 NS1/1-Ag4-1) with spleen cells from BALB/c mice immunized with botulinum type A neurotoxoid. The antibody bound specifically to botulinum type A neurotoxin, showing no cross-reactivity with types B and E botulinum toxins or with any of several other bacterial toxins tested. The monoclonal antibody did not bind to botulinum type A neurotoxin which had been denatured with sodium dodecyl sulfate and bound only weakly to each of the separated heavy and light subunits of the neurotoxin, suggesting a conformational requirement for the antigenic determinant of the antibody. A sensitive immunoassay for C. botulinum type A toxin with monoclonal antibody BA11 in conjunction with an enzyme amplication system has been developed which allows detection of 5 to 10 mouse 50% lethal doses ml-1 of purified neurotoxin. The assay was equally sensitive when applied to the detection of crude toxin in food stuffs; the average value for the minimum level of detectable toxin in extracts of tinned salmon or corned beef was 9 +/- 3.1 mouse 50% lethal doses ml-1. PMID:3927840

  14. Exfoliation reaction of birnessite-type manganese oxide by a host guest electrostatic repulsion in aqueous solution

    NASA Astrophysics Data System (ADS)

    Ma, Biehou; Hou, Wenyan; Han, Yinfeng; Sun, Runguang; Liu, Zong-Huai

    2008-02-01

    The birnessite-type manganese oxide (BirMO) intercalated with 11-aminoundecanoic acid (AUA) as pillared species (BirMO-AUA) was prepared by an ion-exchange method. The prepared BirMO-AUA material was successfully delaminated in an aqueous system by a novel host-guest repulsive interaction process. The delaminated manganese oxide nanosheets were confirmed by XRD, TEM, AFM, and IR analyses. XRD measurement on the slurry centrifuged from the solution showed an amorphous halo and the crystalline phase of BirMO-AUA lost its sharp reflections at pH = 12. Freeze-drying the slurry, the broad pattern was converted into a basal diffraction pattern, indicating the restacking of delaminated manganese oxide nanosheets. AFM and TEM images showed that a large part of BirMO-AUA material was delaminated into one elementary layer at least, and the delaminated nanosheet had a disk-like shape. IR results confirmed that the AUA molecules released from the interlayer accompanied with the delamination process and they could not be restacked into the interlayer by freeze-drying the delaminated nanosheets. The novel delamination process is favorable for negative inorganic layered materials with high layered charge density.

  15. Chemoselective tarantula toxins report voltage activation of wild-type ion channels in live cells.

    PubMed

    Tilley, Drew C; Eum, Kenneth S; Fletcher-Taylor, Sebastian; Austin, Daniel C; Dupré, Christophe; Patrón, Lilian A; Garcia, Rita L; Lam, Kit; Yarov-Yarovoy, Vladimir; Cohen, Bruce E; Sack, Jon T

    2014-11-01

    Electrically excitable cells, such as neurons, exhibit tremendous diversity in their firing patterns, a consequence of the complex collection of ion channels present in any specific cell. Although numerous methods are capable of measuring cellular electrical signals, understanding which types of ion channels give rise to these signals remains a significant challenge. Here, we describe exogenous probes which use a novel mechanism to report activity of voltage-gated channels. We have synthesized chemoselective derivatives of the tarantula toxin guangxitoxin-1E (GxTX), an inhibitory cystine knot peptide that binds selectively to Kv2-type voltage gated potassium channels. We find that voltage activation of Kv2.1 channels triggers GxTX dissociation, and thus GxTX binding dynamically marks Kv2 activation. We identify GxTX residues that can be replaced by thiol- or alkyne-bearing amino acids, without disrupting toxin folding or activity, and chemoselectively ligate fluorophores or affinity probes to these sites. We find that GxTX-fluorophore conjugates colocalize with Kv2.1 clusters in live cells and are released from channels activated by voltage stimuli. Kv2.1 activation can be detected with concentrations of probe that have a trivial impact on cellular currents. Chemoselective GxTX mutants conjugated to dendrimeric beads likewise bind live cells expressing Kv2.1, and the beads are released by channel activation. These optical sensors of conformational change are prototype probes that can indicate when ion channels contribute to electrical signaling. PMID:25331865

  16. Anatomic considerations in botulinum toxin type A therapy for spasmodic dysphonia.

    PubMed

    Castellanos, P F; Gates, G A; Esselman, G; Song, F; Vannier, M W; Kuo, M

    1994-06-01

    Chemodenervation by injection of botulinum toxin type A into the vocal fold(s) has become the preferred treatment for patients with adductor spasmodic dysphonia. Injection may be done either perorally or transcutaneously; each method has its advocates and advantages. The authors have used the transcutaneous transcricothyroid membrane route exclusively with satisfactory results in more than 50 patients. Temporary breathliness and aspiration are common. The preferred injection site should be as close as possible to the motor end plates of the affected muscle. The thyroarytenoid muscle end plates are distributed throughout the muscle, whereas in the lateral cricoarytenoid muscle they are located in band in the center of the muscle. The transcutaneous injection site is below and posterior to the midpoint of the vibrating vocal fold as visualized by indirect laryngoscopy. The proximity of this site to the lateral cricoarytenoid muscle suggests that postinjection breathiness and aspiration may be related to spread of botulinum toxin type A to the lateral cricoarytenoid muscle. However, it is likely that thyroarytenoid muscle paresis is mainly responsible for this side effect and that the rapid clearing of the breathy dysphonia in the face of prolonged relief of spasmodic dysphonia symptoms suggests the action of an adaptive neural response, such as axonal sprouting. Further research of this subject is warranted. PMID:8196438

  17. Development of a quail embryo model for the detection of botulinum toxin type A activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clostridium botulinum is a ubiquitous microorganism which under certain anaerobic conditions can produce botulinum toxins. Due to concerns in regards to both food-borne illness and the potential use of botulinum toxin as a biological weapon, the capability to assess the amount of toxin in a food or...

  18. Enterotoxemia associated with beta2 toxin-producing Clostridium perfringens type A in two Asiatic black bears (Selenarctos thibetanus).

    PubMed

    Greco, Grazia; Madio, Anna; Martella, Vito; Campolo, Marco; Corrente, Marialaura; Buonavoglia, Domenico; Buonavoglia, Canio

    2005-03-01

    Beta2 (beta2) toxin-producing Clostridium perfringens type A strains were found to be associated with necrotic and hemorrhagic intestinal lesions in 2 Asiatic black bears (Selenarctos thibetanus) that died suddenly. Ten isolates were obtained from the liver, lungs, heart, and small and large intestine of the animals and were examined by multiplex polymerase chain reaction for the genes encoding the 4 lethal toxins (alpha, beta, epsilon, and iota) for classification into toxin types as well as for the genes encoding enterotoxin and the novel beta2-toxin for subclassification. In addition, the cpb2 sequence of the 10 isolates was different from the published sequence of cpb2 of pig type C isolate CWC245, whereas it was highly similar to the cpb2 sequence of the C. perfringens type A strain 13. This finding suggests the existence of 2 cpb2 subtypes. This is the first report of enterotoxemia associated with the presence of C. perfringens producing beta2-toxin in the tissues and intestinal content of Asiatic black bears. PMID:15825503

  19. Efficacy of botulinum toxin in pachyonychia congenita type 1: report of two new cases.

    PubMed

    González-Ramos, Jéssica; Sendagorta-Cudós, Elena; González-López, Guillermo; Mayor-Ibarguren, Ander; Feltes-Ochoa, Rosa; Herranz-Pinto, Pedro

    2016-01-01

    Pachyonychia congenita (PC) is a rare genodermatosis caused by a mutation in keratin genes, which can lead to hypertrophic nail dystrophy and focal palmoplantar keratoderma (predominantly plantar), amongst other manifestations. Painful blisters and callosities, sometimes exacerbated by hyperhidrosis, are major issues that can have a significant impact on patient quality of life. Many alternative treatments for this condition have been applied with variable and partial clinical response, but a definitive cure for this disease has yet to be discovered. After obtaining informed consent, two patients with genetically confirmed PC type 1 were treated with plantar injections of botulinum toxin type A. Both patients showed a marked improvement in pain and blistering with an average response time of one week, a six-month mean duration of effectiveness, and a lack of any side effects or tachyphylaxis. PMID:26445325

  20. Inhibition of A-type potassium current by the peptide toxin SNX-482.

    PubMed

    Kimm, Tilia; Bean, Bruce P

    2014-07-01

    SNX-482, a peptide toxin isolated from tarantula venom, has become widely used as an inhibitor of Cav2.3 voltage-gated calcium channels. Unexpectedly, we found that SNX-482 dramatically reduced the A-type potassium current in acutely dissociated dopamine neurons from mouse substantia nigra pars compacta. The inhibition persisted when calcium was replaced by cobalt, showing that it was not secondary to a reduction of calcium influx. Currents from cloned Kv4.3 channels expressed in HEK-293 cells were inhibited by SNX-482 with an IC50 of <3 nM, revealing substantially greater potency than for SNX-482 inhibition of Cav2.3 channels (IC50 20-60 nM). At sub-saturating concentrations, SNX-482 produced a depolarizing shift in the voltage dependence of activation of Kv4.3 channels and slowed activation kinetics. Similar effects were seen on gating of cloned Kv4.2 channels, but the inhibition was less pronounced and required higher toxin concentrations. These results reveal SNX-482 as the most potent inhibitor of Kv4.3 channels yet identified. Because of the effects on both Kv4.3 and Kv4.2 channels, caution is needed when interpreting the effects of SNX-482 on cells and circuits where these channels are present. PMID:25009251

  1. Attomolar Detection of Botulinum Toxin Type A in Complex Biological Matrices

    PubMed Central

    Bagramyan, Karine; Barash, Jason R.; Arnon, Stephen S.; Kalkum, Markus

    2008-01-01

    Background A highly sensitive, rapid and cost efficient method that can detect active botulinum neurotoxin (BoNT) in complex biological samples such as foods or serum is desired in order to 1) counter the potential bioterrorist threat 2) enhance food safety 3) enable future pharmacokinetic studies in medical applications that utilize BoNTs. Methodology/Principal Findings Here we describe a botulinum neurotoxin serotype A assay with a large immuno-sorbent surface area (BoNT/A ALISSA) that captures a low number of toxin molecules and measures their intrinsic metalloprotease activity with a fluorogenic substrate. In direct comparison with the “gold standard” mouse bioassay, the ALISSA is four to five orders of magnitudes more sensitive and considerably faster. Our method reaches attomolar sensitivities in serum, milk, carrot juice, and in the diluent fluid used in the mouse assay. ALISSA has high specificity for the targeted type A toxin when tested against alternative proteases including other BoNT serotypes and trypsin, and it detects the holotoxin as well as the multi-protein complex form of BoNT/A. The assay was optimized for temperature, substrate concentration, size and volume proportions of the immuno-sorbent matrix, enrichment and reaction times. Finally, a kinetic model is presented that is consistent with the observed improvement in sensitivity. Conclusions/Significance The sensitivity, specificity, speed and simplicity of the BoNT ALISSA should make this method attractive for diagnostic, biodefense and pharmacological applications. PMID:18446228

  2. Inhibition of A-Type Potassium Current by the Peptide Toxin SNX-482

    PubMed Central

    Kimm, Tilia

    2014-01-01

    SNX-482, a peptide toxin isolated from tarantula venom, has become widely used as an inhibitor of Cav2.3 voltage-gated calcium channels. Unexpectedly, we found that SNX-482 dramatically reduced the A-type potassium current in acutely dissociated dopamine neurons from mouse substantia nigra pars compacta. The inhibition persisted when calcium was replaced by cobalt, showing that it was not secondary to a reduction of calcium influx. Currents from cloned Kv4.3 channels expressed in HEK-293 cells were inhibited by SNX-482 with an IC50 of <3 nm, revealing substantially greater potency than for SNX-482 inhibition of Cav2.3 channels (IC50 20–60 nm). At sub-saturating concentrations, SNX-482 produced a depolarizing shift in the voltage dependence of activation of Kv4.3 channels and slowed activation kinetics. Similar effects were seen on gating of cloned Kv4.2 channels, but the inhibition was less pronounced and required higher toxin concentrations. These results reveal SNX-482 as the most potent inhibitor of Kv4.3 channels yet identified. Because of the effects on both Kv4.3 and Kv4.2 channels, caution is needed when interpreting the effects of SNX-482 on cells and circuits where these channels are present. PMID:25009251

  3. Identification and Characterization of Type II Toxin-Antitoxin Systems in the Opportunistic Pathogen Acinetobacter baumannii

    PubMed Central

    Jurėnaitė, Milda; Markuckas, Arvydas

    2013-01-01

    Acinetobacter baumannii is an opportunistic pathogen that causes nosocomial infections. Due to the ability to persist in the clinical environment and rapidly acquire antibiotic resistance, multidrug-resistant A. baumannii clones have spread in medical units in many countries in the last decade. The molecular basis of the emergence and spread of the successful multidrug-resistant A. baumannii clones is not understood. Bacterial toxin-antitoxin (TA) systems are abundant genetic loci harbored in low-copy-number plasmids and chromosomes and have been proposed to fulfill numerous functions, from plasmid stabilization to regulation of growth and death under stress conditions. In this study, we have performed a thorough bioinformatic search for type II TA systems in genomes of A. baumannii strains and estimated at least 15 possible TA gene pairs, 5 of which have been shown to be functional TA systems. Three of them were orthologs of bacterial and archaeal RelB/RelE, HicA/HicB, and HigB/HigA systems, and others were the unique SplT/SplA and CheT/CheA TA modules. The toxins of all five TA systems, when expressed in Escherichia coli, inhibited translation, causing RNA degradation. The HigB/HigA and SplT/SplA TA pairs of plasmid origin were highly prevalent in clinical multidrug-resistant A. baumannii isolates from Lithuanian hospitals belonging to the international clonal lineages known as European clone I (ECI) and ECII. PMID:23667234

  4. Epsilon Toxin Is Essential for the Virulence of Clostridium perfringens Type D Infection in Sheep, Goats, and Mice

    PubMed Central

    Garcia, J. P.; Adams, V.; Beingesser, J.; Hughes, M. L.; Poon, R.; Lyras, D.; Hill, A.; McClane, B. A.; Rood, J. I.

    2013-01-01

    Clostridium perfringens type D causes disease in sheep, goats, and other ruminants. Type D isolates produce, at minimum, alpha and epsilon (ETX) toxins, but some express up to five different toxins, raising questions about which toxins are necessary for the virulence of these bacteria. We evaluated the contribution of ETX to C. perfringens type D pathogenicity in an intraduodenal challenge model in sheep, goats, and mice using a virulent C. perfringens type D wild-type strain (WT), an isogenic ETX null mutant (etx mutant), and a strain where the etx mutation has been reversed (etx complemented). All sheep and goats, and most mice, challenged with the WT isolate developed acute clinical disease followed by death in most cases. Sheep developed various gross and/or histological changes that included edema of brain, lungs, and heart as well as hydropericardium. Goats developed various effects, including necrotizing colitis, pulmonary edema, and hydropericardium. No significant gross or histological abnormalities were observed in any mice infected with the WT strain. All sheep, goats, and mice challenged with the isogenic etx mutant remained clinically healthy for ≥24 h, and no gross or histological abnormalities were observed in those animals. Complementation of etx knockout restored virulence; most goats, sheep, and mice receiving this complemented mutant developed clinical and pathological changes similar to those observed in WT-infected animals. These results indicate that ETX is necessary for type D isolates to induce disease, supporting a key role for this toxin in type D disease pathogenesis. PMID:23630957

  5. Shiga Toxin (Stx) Type 1a Reduces the Oral Toxicity of Stx Type 2a

    PubMed Central

    Russo, Lisa M.; Melton-Celsa, Angela R.; O'Brien, Alison D.

    2016-01-01

    Background. Shiga toxin (Stx) is the primary virulence factor of Stx-producing Escherichia coli (STEC). STEC can produce Stx1a and/or Stx2a, which are antigenically distinct. However, Stx2a-producing STEC are associated with more severe disease than strains producing both Stx1a and Stx2a. Methods and Results. To address the hypothesis that the reason for the association of Stx2a with more severe disease is because Stx2a crosses the intestinal barrier with greater efficiency that Stx1a, we covalently labeled Stx1a and Stx2a with Alexa Fluor 750 and determined the ex vivo fluorescent intensity of murine systemic organs after oral intoxication. Surprisingly, both Stxs exhibited similar dissemination patterns and accumulated in the kidneys. We next cointoxicated mice to determine whether Stx1a could impede Stx2a. Cointoxication resulted in increased survival and an extended mean time to death, compared with intoxication with Stx2a only. The survival benefit was dose dependent, with the greatest effect observed when 5 times more Stx1a than Stx2a was delivered, and was amplified when Stx1a was delivered 3 hours prior to Stx2a. Cointoxication with an Stx1a active site toxoid also reduced Stx2a toxicity. Conclusions. These studies suggest that Stx1a reduces Stx2a-mediated toxicity, a finding that may explain why STEC that produce only Stx2a are associated with more severe disease than strains producing Stx1a and Stx2a. PMID:26743841

  6. Recompressed exfoliated graphite articles

    DOEpatents

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2013-08-06

    This invention provides an electrically conductive, less anisotropic, recompressed exfoliated graphite article comprising a mixture of (a) expanded or exfoliated graphite flakes; and (b) particles of non-expandable graphite or carbon, wherein the non-expandable graphite or carbon particles are in the amount of between about 3% and about 70% by weight based on the total weight of the particles and the expanded graphite flakes combined; wherein the mixture is compressed to form the article having an apparent bulk density of from about 0.1 g/cm.sup.3 to about 2.0 g/cm.sup.3. The article exhibits a thickness-direction conductivity typically greater than 50 S/cm, more typically greater than 100 S/cm, and most typically greater than 200 S/cm. The article, when used in a thin foil or sheet form, can be a useful component in a sheet molding compound plate used as a fuel cell separator or flow field plate. The article may also be used as a current collector for a battery, supercapacitor, or any other electrochemical cell.

  7. Botox (Botulinum Toxin)

    MedlinePlus

    ... people when there are many effective and safe cosmetic procedures that can temporarily reduce a very prominent ... form of botulinum toxin is Type A (Botox® Cosmetic, Allergan, Inc). Botulinum toxin, what we will now ...

  8. Rat fat-cells have three types of adenosine receptors (Ra, Ri and P). Differential effects of pertussis toxin.

    PubMed Central

    García-Sáinz, J A; Torner, M L

    1985-01-01

    Activation of rat adipocyte R1 adenosine receptors by phenylisopropyladenosine (PIA) decreased cyclic AMP and lipolysis; this effect was blocked in cells from pertussis-toxin-treated rats. In contrast, the ability of 2',5'-dideoxyadenosine to decrease cyclic AMP was not affected by pertussis-toxin treatment. Addition of adenosine deaminase to the medium in which adipocytes from control animals were incubated resulted in activation of lipolysis. Interestingly, adipocytes from toxin-treated rats (which had an already increased basal lipolysis) responded in an opposite fashion to the addition of adenosine deaminase, i.e. the enzyme decreased lipolysis, which suggested that adenosine might be increasing lipolysis in these cells. Studies with the selective agonists N-ethylcarboxamidoadenosine (NECA) and PIA indicated that adenosine increases lipolysis and cyclic AMP accumulation in these cells and that these actions are mediated through Ra adenosine receptors. Adenosine-mediated accumulation of cyclic AMP was also observed in cells preincubated with pertussis toxin (2 micrograms/ml) for 3 h. In these studies NECA was also more effective than PIA. Our results indicate that there are three types of adenosine receptors in fat-cells, whose actions are affected differently by pertussis toxin, i.e. Ri-mediated actions are abolished, Ra-mediated actions are revealed and P-mediated actions are not affected. PMID:3004405

  9. Improved traceability of Shiga-toxin-producing Escherichia coli using CRISPRs for detection and typing.

    PubMed

    Delannoy, Sabine; Beutin, Lothar; Fach, Patrick

    2016-05-01

    Among strains of Shiga-toxin-producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are frequently associated with severe clinical illness in humans. The development of methods for their reliable detection from complex samples such as food has been challenging thus far, and is currently based on the PCR detection of the major virulence genes stx1, stx2, and eae, and O-serogroup-specific genes. However, this approach lacks resolution. Moreover, new STEC serotypes are continuously emerging worldwide. For example, in May 2011, strains belonging to the hitherto rarely detected STEC serotype O104:H4 were identified as causative agents of one of the world's largest outbreak of disease with a high incidence of hemorrhagic colitis and hemolytic uremic syndrome in the infected patients. Discriminant typing of pathogens is crucial for epidemiological surveillance and investigations of outbreaks, and especially for tracking and tracing in case of accidental and deliberate contamination of food and water samples. Clustered regularly interspaced short palindromic repeats (CRISPRs) are composed of short, highly conserved DNA repeats separated by unique sequences of similar length. This distinctive sequence signature of CRISPRs can be used for strain typing in several bacterial species including STEC. This review discusses how CRISPRs have recently been used for STEC identification and typing. PMID:26449676

  10. Ulcerative enterocolitis in two goats associated with enterotoxin- and beta2 toxin-positive Clostridium perfringens type D.

    PubMed

    Uzal, Francisco A; Fisher, Derek J; Saputo, Juliann; Sayeed, Sameera; McClane, Bruce A; Songer, Glenn; Trinh, Hien T; Fernandez Miyakawa, Mariano E; Gard, Sharon

    2008-09-01

    Enterotoxemia caused by Clostridium perfringens type D in sheep is believed to result from the action of epsilon toxin (ETX). However, the sole role of ETX in the intestinal changes of the acute and chronic forms of enterotoxemia in goats remains controversial, and the synergistic action of other C. perfringens toxins has been suggested previously. The current study examined 2 goats that were found dead without premonitory clinical signs. Gross lesions at necropsy consisted of multifocal fibrinonecrotic enterocolitis, edematous lungs, and excess pleural fluid. Histologically, there were multifocal fibrinonecrotic and ulcerative ileitis and colitis, edema of the colonic serosa, and proteinaceous interstitial edema of the lungs. Clostridium perfringens type D carrying the genes for enterotoxin (CPE) and beta2 toxin (CPB2) was cultured from intestinal content and feces of 1 of 2 goats, while C. perfringens type D CPB2-positive was isolated from the other animal. When multiple colonies of the primary isolations from both animals were tested by Western blot, most of the isolates expressed CPB2, and only a few isolates from the first case expressed CPE. Alpha toxin and ETX were detected in ileal and colonic contents and feces of both animals by antigen capture enzyme-linked immunosorbent assay. CPB2, but not CPE, was identified in the small and large intestines of both goats by immunohistochemistry. These findings indicate that CPB2 may have contributed to the necrotic changes observed in the intestine, possibly assisting ETX transit across the intestinal mucosa. PMID:18776108

  11. Evaluation of a quail embryo model for the detection of botulinum toxin type A activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The quail embryo was evaluated for use as a bioassay to detect biologically active botulinum toxin serotype A (BoNT/A). Day 15 of incubation embryos were injected with decreasing dosages of BoNT/A from 250 to 0.5 ng of toxin. At 1 day post-injection, embryos receiving 20 ng of BoNT or higher had m...

  12. Utilization of quail and chicken embryos for the detection of botulinum toxin type A activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clostridium botulinum is a ubiquitous microorganism which can produce botulinum toxins and the ability to assess toxin activity in a food sample is critical. As an alternative to the mouse assay incubating quail (Coturnix coturnix japonica) and chicken (Gallus gallus domestics) embryos were evaluat...

  13. Evaluation of a quali embryo model for the detection of botulism toxin type A activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Japanese quail embryo (Coturnix japonica) was evaluated for use as a bioassay to detect biologically active botulinum toxin serotype A (BoNT/A). Day 15 of incubation embryos were injected with decreasing dosages of BoNT/A from 250 to 0.5 ng of toxin. At 1 day post-injection, embryos receiving ...

  14. Molecular Resolution in situ Imaging of Spontaneous Graphene Exfoliation.

    PubMed

    Elbourne, Aaron; McLean, Ben; Voïtchovsky, Kislon; Warr, Gregory G; Atkin, Rob

    2016-08-18

    All reported methods of graphene exfoliation require external energy input, most commonly from sonication,1 shaking,2 or stirring.3 The reverse process-aggregation of single or few layer graphene sheets-occurs spontaneously in most solvents. This makes producing, and especially storing, graphene in economic quantities challenging,4,5 which is a significant barrier to widespread commercialization. This study reveals ionic liquids (ILs) can spontaneously exfoliate graphene from graphite at room temperature. The process is thermally activated and follows an Arrhenius-type behavior, resulting in thermodynamically stable IL/graphene suspensions. Using atomic force microscopy, the kinetics of the exfoliation could be followed in situ and with subnanometer resolution, showing that both the size and the charge of the constituent IL ions play a key role. Our results provide a general molecular mechanism underpinning spontaneous graphene exfoliation at room temperature in electrically conducting ILs, paving the way for their adoption in graphene-based technology. PMID:27463824

  15. Toxins that are activated by HIV type-1 protease through removal of a signal for degradation by the N-end-rule pathway.

    PubMed Central

    Falnes, P O; Welker, R; Kräusslich, H G; Olsnes, S

    1999-01-01

    Diphtheria toxin enters the cytosol of mammalian cells where it inhibits cellular protein synthesis, leading to cell death. Recently we found that the addition of a signal for N-end-rule-mediated protein degradation to diphtheria toxin substantially reduced its intracellular stability and toxicity. These results prompted us to construct a toxin containing a degradation signal that is removable through the action of a viral protease. In principle, such a toxin would be preferentially stabilized, and thus activated, in cells expressing the viral protease in the cytosol, i.e. virus-infected cells, thereby providing a specific eradication of these cells. In the present work we describe the construction of toxins that contain a signal for N-end-rule-mediated degradation just upstream of a cleavage site for the protease from HIV type 1 (HIV-1 PR). We show that the toxins are cleaved by HIV-1 PR exclusively at the introduced sites, and thereby are converted from unstable to stable proteins. Furthermore, this cleavage substantially increased the ability of the toxins to inhibit cellular protein synthesis. However, the toxins were unable to selectively eradicate HIV-1-infected cells, apparently due to low cytosolic HIV-1 PR activity, since we could not detect cleavage of the toxins by HIV-1 PR in infected cells. Alternative strategies for the construction of toxins that can specifically be activated by viral proteases are discussed. PMID:10493930

  16. Lumbar Sympathetic Block with Botulinum Toxin Type B for Complex Regional Pain Syndrome: A Case Study.

    PubMed

    Choi, Eunjoo; Cho, Chan Woo; Kim, Hye Young; Lee, Pyung Bok; Nahm, Francis Sahngun

    2015-01-01

    Lumbar sympathetic block (LSB) is an effective method for relief of sympathetically mediated pain in the lower extremities. To prolong the sympathetic blockade, sympathetic destruction with alcohol or radiofrequency has been used. The pre-ganglionic sympathetic nerves are cholinergic, and botulinum toxin (BTX) has been found to inhibit the release of acetylcholine at the cholinergic nerve terminals. Moreover, BTX type B (BTX-B) is more convenient to use than BTX type A. Based on these findings, we performed LSB on the 2 patients with complex regional pain syndrome (CRPS) in the lower extremity. Levobupivacaine 0.25% 5 mL mixed with BTX-B 5,000 IU was given under fluoroscopic guidance. Two months after LSB with BTX-B, pain intensity and the Leeds assessment of neuropathic symptoms and signs (LANSS) score were significantly reduced. Allodynia and coldness disappeared and skin color came back to normal. In conclusion, BTX-B can produce an efficacious and durable sympathetic blocking effect on patients with CRPS. PMID:26431145

  17. Capturing the interaction types of two Bt toxins Cry1Ac and Cry2Ab on suppressing the cotton bollworm by using multi-exponential equations.

    PubMed

    Shi, Pei-Jian; Wei, Ji-Zhen; Sandhu, Hardev S; Liang, Ge-Mei

    2016-08-01

    Transgenic crops are increasingly promoted for their practical effects on suppressing certain insect pests, but all transgenic crops are not equally successful. The insect pests can easily develop resistance against single Bacillus thuringiensis (Bt) toxin transgenic crops. Therefore, transgenic crops including two or more mixed Bt-toxins can solve this problem by delaying the resistance development and killing the majority of targeted pests before the evolution of resistance. It is important to test the controlling effects of transgenic crops including multiple mixed toxins on a particular insect pest. Previous research has checked the cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against one susceptible and four resistant strains of cotton bollworm. The results showed that independence was the main interaction type between two toxins for the susceptible strain, whereas synergism was the main interaction type for any one resistant strain. However, the optimal combinations of two toxins were not obtained. In the present study, we developed two multi-exponential equations (namely bi- and tri-exponential equations) to describe the combination effects of two Bt toxins. Importantly, the equations can provide predictions of combination effects of different continuous concentrations of two toxins. We compared these two multi-exponential equations with the generalized linear model (GLM) in describing the combination effects, and found that the bi- and tri-exponential equations are better than GLM. Moreover, the bi-exponential equation can also provide the optimal dose combinations for two toxins. PMID:26314801

  18. Detection, Characterization, and Typing of Shiga Toxin-Producing Escherichia coli

    PubMed Central

    Parsons, Brendon D.; Zelyas, Nathan; Berenger, Byron M.; Chui, Linda

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) are responsible for gastrointestinal diseases reported in numerous outbreaks around the world. Given the public health importance of STEC, effective detection, characterization and typing is critical to any medical laboratory system. While non-O157 serotypes account for the majority of STEC infections, frontline microbiology laboratories may only screen for STEC using O157-specific agar-based methods. As a result, non-O157 STEC infections are significantly under-reported. This review discusses recent advances on the detection, characterization and typing of STEC with emphasis on work performed at the Alberta Provincial Laboratory for Public Health (ProvLab). Candidates for the detection of all STEC serotypes include chromogenic agars, enzyme immunoassays (EIA) and quantitative real time polymerase chain reaction (qPCR). Culture methods allow further characterization of isolates, whereas qPCR provides the greatest sensitivity and specificity, followed by EIA. The virulence gene profiles using PCR arrays and stx gene subtypes can subsequently be determined. Different non-O157 serotypes exhibit markedly different virulence gene profiles and a greater prevalence of stx1 than stx2 subtypes compared to O157:H7 isolates. Finally, recent innovations in whole genome sequencing (WGS) have allowed it to emerge as a candidate for the characterization and typing of STEC in diagnostic surveillance isolates. Methods of whole genome analysis such as single nucleotide polymorphisms and k-mer analysis are concordant with epidemiological data and standard typing methods, such as pulsed-field gel electrophoresis and multiple-locus variable number tandem repeat analysis while offering additional strain differentiation. Together these findings highlight improved strategies for STEC detection using currently available systems and the development of novel approaches for future surveillance. PMID:27148176

  19. Directed Therapy for Exfoliation Syndrome

    PubMed Central

    Angelilli, Allison; Ritch, Robert

    2009-01-01

    Exfoliation syndrome (XFS) is an age-related disorder of the extracellular matrix that leads the production of abnormal fibrillar material that leads to elevated intraocular pressure and a relatively severe glaucoma. Exfoliation material is deposited in numerous ocular tissues and extraocular organs. XFS is associated with ocular ischemia, cerebrovascular disease, neurodegenerative disease and cardiovascular disease. Current modalities of treatment include intraocular pressure lowering with topical antihypertensives, laser trabeculoplasty and filtration surgery. The disease paradigm for XFS should be expanded to include directed therapy designed specifically to target the underlying disease process. Potential targets include preventing the formation or promoting the depolymerization of exfoliation material. Novel therapies targeting trabecular meshwork may prove particularly useful in the care of exfoliative glaucoma. The systemic and ocular associations of XFS underscore the need for a comprehensive search for neuroprotective agents in its treatment. PMID:19888433

  20. Lysogeny with Shiga Toxin 2-Encoding Bacteriophages Represses Type III Secretion in Enterohemorrhagic Escherichia coli

    PubMed Central

    Xu, Xuefang; McAteer, Sean P.; Tree, Jai J.; Shaw, Darren J.; Wolfson, Eliza B. K.; Beatson, Scott A.; Roe, Andrew J.; Allison, Lesley J.; Chase-Topping, Margo E.; Mahajan, Arvind; Tozzoli, Rosangela; Woolhouse, Mark E. J.; Morabito, Stefano; Gally, David L.

    2012-01-01

    Lytic or lysogenic infections by bacteriophages drive the evolution of enteric bacteria. Enterohemorrhagic Escherichia coli (EHEC) have recently emerged as a significant zoonotic infection of humans with the main serotypes carried by ruminants. Typical EHEC strains are defined by the expression of a type III secretion (T3S) system, the production of Shiga toxins (Stx) and association with specific clinical symptoms. The genes for Stx are present on lambdoid bacteriophages integrated into the E. coli genome. Phage type (PT) 21/28 is the most prevalent strain type linked with human EHEC infections in the United Kingdom and is more likely to be associated with cattle shedding high levels of the organism than PT32 strains. In this study we have demonstrated that the majority (90%) of PT 21/28 strains contain both Stx2 and Stx2c phages, irrespective of source. This is in contrast to PT 32 strains for which only a minority of strains contain both Stx2 and 2c phages (28%). PT21/28 strains had a lower median level of T3S compared to PT32 strains and so the relationship between Stx phage lysogeny and T3S was investigated. Deletion of Stx2 phages from EHEC strains increased the level of T3S whereas lysogeny decreased T3S. This regulation was confirmed in an E. coli K12 background transduced with a marked Stx2 phage followed by measurement of a T3S reporter controlled by induced levels of the LEE-encoded regulator (Ler). The presence of an integrated Stx2 phage was shown to repress Ler induction of LEE1 and this regulation involved the CII phage regulator. This repression could be relieved by ectopic expression of a cognate CI regulator. A model is proposed in which Stx2-encoding bacteriophages regulate T3S to co-ordinate epithelial cell colonisation that is promoted by Stx and secreted effector proteins. PMID:22615557

  1. Lysogeny with Shiga toxin 2-encoding bacteriophages represses type III secretion in enterohemorrhagic Escherichia coli.

    PubMed

    Xu, Xuefang; McAteer, Sean P; Tree, Jai J; Shaw, Darren J; Wolfson, Eliza B K; Beatson, Scott A; Roe, Andrew J; Allison, Lesley J; Chase-Topping, Margo E; Mahajan, Arvind; Tozzoli, Rosangela; Woolhouse, Mark E J; Morabito, Stefano; Gally, David L

    2012-01-01

    Lytic or lysogenic infections by bacteriophages drive the evolution of enteric bacteria. Enterohemorrhagic Escherichia coli (EHEC) have recently emerged as a significant zoonotic infection of humans with the main serotypes carried by ruminants. Typical EHEC strains are defined by the expression of a type III secretion (T3S) system, the production of Shiga toxins (Stx) and association with specific clinical symptoms. The genes for Stx are present on lambdoid bacteriophages integrated into the E. coli genome. Phage type (PT) 21/28 is the most prevalent strain type linked with human EHEC infections in the United Kingdom and is more likely to be associated with cattle shedding high levels of the organism than PT32 strains. In this study we have demonstrated that the majority (90%) of PT 21/28 strains contain both Stx2 and Stx2c phages, irrespective of source. This is in contrast to PT 32 strains for which only a minority of strains contain both Stx2 and 2c phages (28%). PT21/28 strains had a lower median level of T3S compared to PT32 strains and so the relationship between Stx phage lysogeny and T3S was investigated. Deletion of Stx2 phages from EHEC strains increased the level of T3S whereas lysogeny decreased T3S. This regulation was confirmed in an E. coli K12 background transduced with a marked Stx2 phage followed by measurement of a T3S reporter controlled by induced levels of the LEE-encoded regulator (Ler). The presence of an integrated Stx2 phage was shown to repress Ler induction of LEE1 and this regulation involved the CII phage regulator. This repression could be relieved by ectopic expression of a cognate CI regulator. A model is proposed in which Stx2-encoding bacteriophages regulate T3S to co-ordinate epithelial cell colonisation that is promoted by Stx and secreted effector proteins. PMID:22615557

  2. None detectable retrograde transport of Chinese botulinum toxin type A in mice by single intramuscular injection

    PubMed Central

    Hong, Bin; Yao, Lin-Lin; Hu, Xing-Yue

    2015-01-01

    Botulinum toxin type A (BoNT/A) can specifically cleave synaptosomal associated protein of 25 kDa (SNAP-25) into cleaved SNAP-25 (cl.SNAP-25), thus blocking the synaptic transmission in motor end plate and resulting in paralysis. It has been widely applied in clinical for treatment of various conditions characterized by muscle hyperactivity, such as dystonia and spasticity. BoNT/A is used locally, with little diffusion. Its paralyzing role is considered to be restricted to the nerve muscle junction, or close to the injection site. Recently, more and more studies, however, have suggested that BoNT/A also has central effects. In addition, some investigators have demonstrated that BoNT/A enters into central nervous system via retrograde transport after local intramuscular administration. The retrograde axonal transport of Chinese BoNT/A (CBoNT/A) was studied in this paper, which was rare in report. And the results showed that cl.SNAP-25 appeared not only at the injection site but also in contralateral muscle. Retrograde transport, however, was non-existent or too little to be detected in our study. PMID:26629081

  3. Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin

    PubMed Central

    Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P. N.; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino

    2016-01-01

    Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. PMID:27030589

  4. Efficacy and Safety of a New Botulinum Toxin Type A Free of Complexing Proteins

    PubMed Central

    Oh, Hyun-Mi; Park, Joo Hyun; Song, Dae Heon; Chung, Myung Eun

    2015-01-01

    MT10107 is botulinum neurotoxin type A derived drug which utilizes the 150 kDa portion without complexing proteins and human serum albumin contents. To evaluate the efficacy and the safety of MT10107, it was compared with onabotulinumtoxinA in this double-blind, randomized controlled trial. Twenty-five healthy males received a randomly selected dose of MT10107 into the extensor digitorum brevis (EDB) muscle of one foot, and an equivalent dose of onabotulinumtoxinA (BOTOX) was injected into the contralateral EDB muscle. While efficacy of the administered substance was determined by measuring paretic effects on the EDB, the local spread of toxin effects was evaluated by the paretic effects on the nearby abductor hallucis (AH) and abductor digiti quinti (ADQ) muscles. Paretic effects were defined as the percentage of reduction of the compound muscle action potential (CMAP) amplitudes, measured at 14, 30, 90 days after the injection, compared to the baseline value. Intergroup (MT10107 and onabotulinumtoxinA) differences were not significant in the percentage reduction of the amplitudes in the EDB muscles. In this study, there was no significant difference in efficacy and safety between the two test drugs. MT10107 may be effective and safe as much as onabotulinumtoxinA to produce the desired paretic effect. PMID:26712786

  5. Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin.

    PubMed

    Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P N; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino; Ferlenghi, Ilaria; Bagnoli, Fabio

    2016-06-01

    Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. PMID:27030589

  6. Therapeutic efficacy and safety of botulinum toxin type A in trigeminal neuralgia: a systematic review

    PubMed Central

    2013-01-01

    Trigeminal neuralgia is a common disorder caused mainly by compression of the trigeminal nerve root by an overlying blood vessel. Pharmacotherapy and surgery are ineffective or unsuitable in many patients. Therefore, other therapeutic modalities have been tried, including injection of botulinum toxin type A (BTX-A). This study aims to systematically review the therapeutic efficacy and safety of BTX-A in trigeminal neuralgia. PubMed, EMBASE, Cochrane Library Clinical Trials and Web of Science from January 1966 to March 2013 were searched with the terms of “botulinum toxin” AND “trigeminal neuralgia”, and references of related articles were traced. Data on the efficacy and safety of BTX-A in this disorder were extracted and analyzed by at least 2 reviewers. Data for individual studies were reported, and pooled data were analyzed if appropriate. Five prospective studies and one double-blind, randomized, placebo-controlled study were identified. Response was achieved in approximately 70-100% of patients, and the mean pain intensity and frequency were reduced by approximately 60-100% at 4 weeks after treatment in most studies. Major adverse events were not reported. Available studies show BTX-A may be effective in treatment of trigeminal neuralgia. However, well-designed randomized, controlled, double-blinded trial is still lacking. Future BTX-A treatment studies on optimal dose, duration of the therapeutic efficacy, common AEs, and the time and indications for repeat injection would be promising. PMID:23964790

  7. Ultrasound-Guided Nerve Block with Botulinum Toxin Type A for Intractable Neuropathic Pain

    PubMed Central

    Moon, Young Eun; Choi, Jung Hyun; Park, Hue Jung; Park, Ji Hye; Kim, Ji Hyun

    2016-01-01

    Neuropathic pain includes postherpetic neuralgia (PHN), painful diabetic neuropathy (PDN), and trigeminal neuralgia, and so on. Although various drugs have been tried to treat neuropathic pain, the effectiveness of the drugs sometimes may be limited for chronic intractable neuropathic pain, especially when they cannot be used at an adequate dose, due to undesirable severe side effects and the underlying disease itself. Botulinum toxin type A (BoNT-A) has been known for its analgesic effect in various pain conditions. Nevertheless, there are no data of nerve block in PHN and PDN. Here, we report two patients successfully treated with ultrasound-guided peripheral nerve block using BoNT-A for intractable PHN and PDN. One patient had PHN on the left upper extremity and the other patient had PDN on a lower extremity. Due to side effects of drugs, escalation of the drug dose could not be made. We injected 50 Botox units (BOTOX®, Allergan Inc., Irvine, CA, USA) into brachial plexus and lumbar plexus, respectively, under ultrasound. Their pain was significantly decreased for about 4–5 months. Ultrasound-guided nerve block with BoNT-A may be an effective analgesic modality in a chronic intractable neuropathic pain especially when conventional treatment failed to achieve adequate pain relief. PMID:26761032

  8. Extended effect after a single dose of type A botulinum toxin for asymmetric masseter muscle hypertrophy

    PubMed Central

    Bhattacharjee, Kasturi; Singh, Manpreet; Bhattacharjee, Harsha

    2015-01-01

    Facial asymmetry can either be physiological or pathological and is a common cosmetic concern. A 35-year-old Indian male presented with broad appearing lower face and prominent left jaw since adolescence. Parotid enlargement and other local disorders were ruled out. Ultrasonographic thickness of right masseter muscle was 13 mm while that of left was 14.9 mm, in unclenched state. Type-A botulinum toxin (T-ABT) was injected, evenly at five points, in both muscles within the “safe zone”. Using a 29 gauge needle, 15 and 25 international units were delivered to right and left masseters, respectively. Six months post — injection, a reduction of 2.9 mm and 4.4 mm was observed along with a reduced external facial asymmetry. At 24 months, patient maintains a satisfactory facial contour with no significant early or late post-injection complications. Intra-massteric injection of T-ABT can be used effectively as a primary or adjunct procedure for holistic oculo-facial sculpting. PMID:26424987

  9. Efficacy and Safety of a New Botulinum Toxin Type A Free of Complexing Proteins.

    PubMed

    Oh, Hyun-Mi; Park, Joo Hyun; Song, Dae Heon; Chung, Myung Eun

    2016-01-01

    MT10107 is botulinum neurotoxin type A derived drug which utilizes the 150 kDa portion without complexing proteins and human serum albumin contents. To evaluate the efficacy and the safety of MT10107, it was compared with onabotulinumtoxinA in this double-blind, randomized controlled trial. Twenty-five healthy males received a randomly selected dose of MT10107 into the extensor digitorum brevis (EDB) muscle of one foot, and an equivalent dose of onabotulinumtoxinA (BOTOX) was injected into the contralateral EDB muscle. While efficacy of the administered substance was determined by measuring paretic effects on the EDB, the local spread of toxin effects was evaluated by the paretic effects on the nearby abductor hallucis (AH) and abductor digiti quinti (ADQ) muscles. Paretic effects were defined as the percentage of reduction of the compound muscle action potential (CMAP) amplitudes, measured at 14, 30, 90 days after the injection, compared to the baseline value. Intergroup (MT10107 and onabotulinumtoxinA) differences were not significant in the percentage reduction of the amplitudes in the EDB muscles. In this study, there was no significant difference in efficacy and safety between the two test drugs. MT10107 may be effective and safe as much as onabotulinumtoxinA to produce the desired paretic effect. PMID:26712786

  10. Ultrasound-Guided Nerve Block with Botulinum Toxin Type A for Intractable Neuropathic Pain.

    PubMed

    Moon, Young Eun; Choi, Jung Hyun; Park, Hue Jung; Park, Ji Hye; Kim, Ji Hyun

    2016-01-01

    Neuropathic pain includes postherpetic neuralgia (PHN), painful diabetic neuropathy (PDN), and trigeminal neuralgia, and so on. Although various drugs have been tried to treat neuropathic pain, the effectiveness of the drugs sometimes may be limited for chronic intractable neuropathic pain, especially when they cannot be used at an adequate dose, due to undesirable severe side effects and the underlying disease itself. Botulinum toxin type A (BoNT-A) has been known for its analgesic effect in various pain conditions. Nevertheless, there are no data of nerve block in PHN and PDN. Here, we report two patients successfully treated with ultrasound-guided peripheral nerve block using BoNT-A for intractable PHN and PDN. One patient had PHN on the left upper extremity and the other patient had PDN on a lower extremity. Due to side effects of drugs, escalation of the drug dose could not be made. We injected 50 Botox units (BOTOX(®), Allergan Inc., Irvine, CA, USA) into brachial plexus and lumbar plexus, respectively, under ultrasound. Their pain was significantly decreased for about 4-5 months. Ultrasound-guided nerve block with BoNT-A may be an effective analgesic modality in a chronic intractable neuropathic pain especially when conventional treatment failed to achieve adequate pain relief. PMID:26761032

  11. Inhibitory Effects of Botulinum Toxin Type A on Pyloric Cholinergic Muscle Contractility of Rat.

    PubMed

    Zhao, Peng; Sun, Hong-Xu; Chu, Min; Hou, Yi-Ping

    2016-08-31

    Botulinum toxin type A (BTX-A) selectively cleaves synaptosomal-associated protein of 25 kDa (SNAP-25) and results in inhibition of the fusion of synaptic vesicles containing neurotransmitters with the presynaptic membrane to undergo exocytosis and release. The aim of this study was to investigate whether BTX-A inhibited the pyloric smooth muscle contractility induced by acetylcholine (ACh) after BTX-A-mediated cleavage of SNAP-25 antagonized by toosendanin (TSN). Three groups of rat pyloric muscle strips were studied in vitro. All strips were allowed to equilibrate for 52 min under a basal loading tension of 1 g in Krebs solution and spontaneous contractile waves were recorded as their own controls before adding each drug. According to experimental protocols, 100 μM ACh, 1 μM atropine, 29.6 μM TSN and 10 U/ml BTX-A was added, respectively. BTX-A directly inhibited pyloric spontaneous contraction and ACh-induced contractile response. Addition of 10 U/ml BTX-A still inhibited pyloric smooth muscle contractility following incubation of TSN, while subsequent administration of 100 μM ACh had no effect. BTX-A inhibits pyloric smooth muscle contractility in our study suggesting BTX-A inhibits not only ACh release from cholinergic nerves but also muscarinic cholinergic muscular transmission. PMID:27426259

  12. Botulinum toxin type A (Botox) and idiopathic overactive bladder. For some severely affected patients.

    PubMed

    2016-03-01

    In two clinical trials, botulinum toxin injected during cystoscopy transiently prevented urinary incontinence in 1 in 5 patients but sometimes provoked urine retention and urinary tract infections. PMID:27152397

  13. The gene for type A streptococcal exotoxin (erythrogenic toxin) is located in bacteriophage T12.

    PubMed Central

    Weeks, C R; Ferretti, J J

    1984-01-01

    The infection of Streptococcus pyogenes T25(3) with the temperate bacteriophage T12 results in the conversion of the nontoxigenic strain to type A streptococcal exotoxin (erythrogenic toxin) production. Although previous research has established that integration of the bacteriophage genome into the host chromosome is not essential for exotoxin production, the location of the gene on the bacteriophage or bacterial chromosome had not been determined. In the present investigation, recombinant DNA techniques were used to determine whether the gene specifying type A streptococcal exotoxin (speA) production is located on the bacteriophage chromosome. Bacteriophage T12 was obtained from S. pyogenes T25(3)(T12) by induction with mitomycin C, and after isolation of bacteriophage DNA by phenol-chloroform extraction, the DNA was digested with restriction enzymes and ligated with Escherichia coli plasmid pHP34 or the Streptococcus-E. coli shuttle vector pSA3. Transformation of E. coli HB101 with the recombinant molecules allowed selection of E. coli clones containing bacteriophage T12 genes. Immunological assays with specific antibody revealed the presence of type A streptococcal exotoxin in sonicates of E. coli transformants. Subcloning experiments localized the speA gene to a 1.7-kilobase segment of the bacteriophage T12 genome flanked by SalI and HindIII sites. Introduction of the pSA3 vector containing the speA gene into Streptococcus sanguis (Challis) resulted in transformants that secreted the type A exotoxin. Immunological analysis showed that the type A streptococcal exotoxin produced by E. coli and S. sanguis transformants was identical to the type A exotoxin produced by S. pyogenes T25(3)(T12). Southern blot hybridizations with the cloned fragment confirmed its presence in the bacteriophage T12 genome and its absence in the T25(3) nonlysogen. Therefore, the gene for type A streptococcal exotoxin is located in the bacteriophage genome, and conversion of S. pyogenes T

  14. Novel spider toxin slows down the activation kinetics of P-type Ca2+ channels in Purkinje neurons of rat.

    PubMed

    Fisyunov, Alexander; Pluzhnikov, Kirill; Molyavka, Anton; Grishin, Eugene; Lozovaya, Natalia; Krishtal, Oleg

    2005-02-01

    We have identified a novel polypeptide toxin (Lsp-1) from the venom of the spider Lycosa (LS). Its effect has been examined on the P-type calcium channels in Purkinje neurons, using whole-cell patch-clamp. This toxin (at saturating concentration 7 nM) produces prominent (four-fold) deceleration of the activation kinetics and partial (71+/-6%) decrease of the amplitude of P-current without affecting either deactivation or inactivation kinetics. These effects are not use-dependent. They are partially reversible within a minute upon the wash-out of the toxin. Intracellular perfusion of Purkinje neurons with 100 microM of GDP or 2 microM of GTPgammaS, as well as strong depolarising pre-pulses (+100 mV), do not eliminate the action of Lsp-1 on P-channels indicating that down-modulation via guanine nucleotide-binding proteins (G-proteins) is not involved in the observed phenomenon. In view of extremely high functional significance of P-channels, the toxin can be suggested as a useful pharmacological tool. PMID:15590128

  15. In Vitro Characterization of the Type I Toxin-Antitoxin System bsrE/SR5 from Bacillus subtilis.

    PubMed

    Meißner, Christin; Jahn, Natalie; Brantl, Sabine

    2016-01-01

    BsrE/SR5 is a new type I toxin/antitoxin system located on the prophage-like region P6 of the Bacillus subtilis chromosome. The bsrE gene encoding a 30-amino acid hydrophobic toxin and the antitoxin gene sr5 overlap at their 3' ends by 112 bp. Overexpression of bsrE causes cell lysis on agar plates. Here, we present a detailed in vitro analysis of bsrE/SR5. The secondary structures of SR5, bsrE mRNA, and the SR5/bsrE RNA complex were determined. Apparent binding rate constants (kapp) of wild-type and mutated SR5 species with wild-type bsrE mRNA were calculated, and SR5 regions required for efficient inhibition of bsrE mRNA narrowed down. In vivo studies confirmed the in vitro data but indicated that a so far unknown RNA binding protein might exist in B. subtilis that can promote antitoxin/toxin RNA interaction. Using time course experiments, the binding pathway of SR5 and bsrE RNA was elucidated. A comparison with the previously well characterized type I TA system from the B. subtilis chromosome, bsrG/SR4, reveals similarities but also significant differences. PMID:26565032

  16. Role of the Agr-like quorum-sensing system in regulating toxin production by Clostridium perfringens type B strains CN1793 and CN1795.

    PubMed

    Chen, Jianming; McClane, Bruce A

    2012-09-01

    Clostridium perfringens type B causes enteritis and enterotoxemia in domestic animals. By definition, these bacteria must produce alpha toxin (CPA), beta toxin (CPB) and epsilon toxin (ETX) although most type B strains also produce perfringolysin O (PFO) and beta2 toxin (CPB2). A recently identified Agr-like quorum-sensing (QS) system in C. perfringens controls all toxin production by surveyed type A, C, and D strains, but whether this QS is involved in regulating toxin production by type B strains has not been explored. Therefore, the current study introduced agrB null mutations into type B strains CN1795 and CN1793. Both type B agrB null mutants exhibited reduced levels of CPB, PFO, and CPA in their culture supernatants, and this effect was reversible by complementation. The reduced presence of CPB in culture supernatant involved decreased cpb transcription. In contrast, the agrB null mutants of both type B strains retained wild-type production levels of ETX and CPB2. In a Caco-2 cell model of enteritis, culture supernatants of the type B agrB null mutants were less cytotoxic than supernatants of their wild-type parents. However, in an MDCK cell in vitro model for enterotoxemic effects, supernatants from the agrB null mutants or wild-type parents were equally cytotoxic after trypsin activation. Coupling these and previous results, it is now evident that strain-dependent variations exist in Agr-like QS system regulation of C. perfringens toxin production. The cell culture results further support a role for trypsin in determining which toxins contribute to disease involving type B strains. PMID:22689820

  17. Role of the Agr-Like Quorum-Sensing System in Regulating Toxin Production by Clostridium perfringens Type B Strains CN1793 and CN1795

    PubMed Central

    Chen, Jianming

    2012-01-01

    Clostridium perfringens type B causes enteritis and enterotoxemia in domestic animals. By definition, these bacteria must produce alpha toxin (CPA), beta toxin (CPB) and epsilon toxin (ETX) although most type B strains also produce perfringolysin O (PFO) and beta2 toxin (CPB2). A recently identified Agr-like quorum-sensing (QS) system in C. perfringens controls all toxin production by surveyed type A, C, and D strains, but whether this QS is involved in regulating toxin production by type B strains has not been explored. Therefore, the current study introduced agrB null mutations into type B strains CN1795 and CN1793. Both type B agrB null mutants exhibited reduced levels of CPB, PFO, and CPA in their culture supernatants, and this effect was reversible by complementation. The reduced presence of CPB in culture supernatant involved decreased cpb transcription. In contrast, the agrB null mutants of both type B strains retained wild-type production levels of ETX and CPB2. In a Caco-2 cell model of enteritis, culture supernatants of the type B agrB null mutants were less cytotoxic than supernatants of their wild-type parents. However, in an MDCK cell in vitro model for enterotoxemic effects, supernatants from the agrB null mutants or wild-type parents were equally cytotoxic after trypsin activation. Coupling these and previous results, it is now evident that strain-dependent variations exist in Agr-like QS system regulation of C. perfringens toxin production. The cell culture results further support a role for trypsin in determining which toxins contribute to disease involving type B strains. PMID:22689820

  18. Botulinum toxin type-A injection to treat patients with intractable anismus unresponsive to simple biofeedback training

    PubMed Central

    Zhang, Yong; Wang, Zhen-Ning; He, Lei; Gao, Ge; Zhai, Qing; Yin, Zhi-Tao; Zeng, Xian-Dong

    2014-01-01

    AIM: To evaluate the efficacy of botulinum toxin type A injection to the puborectalis and external sphincter muscle in the treatment of patients with anismus unresponsive to simple biofeedback training. METHODS: This retrospective study included 31 patients suffering from anismus who were unresponsive to simple biofeedback training. Diagnosis was made by anorectal manometry, balloon expulsion test, surface electromyography of the pelvic floor muscle, and defecography. Patients were given botulinum toxin type A (BTX-A) injection and pelvic floor biofeedback training. Follow-up was conducted before the paper was written. Improvement was evaluated using the chronic constipation scoring system. RESULTS: BTX-A injection combined with pelvic floor biofeedback training achieved success in 24 patients, with 23 maintaining persistent satisfaction during a mean period of 8.4 mo. CONCLUSION: BTX-A injection combined with pelvic floor biofeedback training seems to be successful for intractable anismus. PMID:25253964

  19. Crystallization and preliminary X-ray analysis of the HA3 component of Clostridium botulinum type C progenitor toxin

    SciTech Connect

    Nakamura, Toshio; Tonozuka, Takashi; Kotani, Mao; Obata, Kanae; Oguma, Keiji; Nishikawa, Atsushi

    2007-12-01

    HA3, a 70 kDa haemagglutinating protein, is a precursor form of HA3a and HA3b, the subcomponents of Clostridium botulinum type C 16S progenitor toxin. In this report, recombinant HA3 protein was overexpressed in Escherichia coli, purified and crystallized. HA3, a 70 kDa haemagglutinating protein, is a precursor form of HA3a and HA3b, the subcomponents of Clostridium botulinum type C 16S progenitor toxin. In this report, recombinant HA3 protein was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.6 Å resolution and the crystal belonged to the hexagonal space group P6{sub 3}. Matthews coefficient and self-rotation function calculations indicate that there is probably one molecule of HA3 in the asymmetric unit. A search for heavy-atom derivatives has been undertaken.

  20. The effect of Clostridium perfringens type C strain CN3685 and its isogenic beta toxin null mutant in goats.

    PubMed

    Garcia, J P; Beingesser, J; Fisher, D J; Sayeed, S; McClane, B A; Posthaus, H; Uzal, F A

    2012-06-15

    Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch's postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis. PMID:22296994

  1. The effect of Clostridium perfringens type C strain CN3685 and its isogenic beta toxin null mutant in goats

    PubMed Central

    Garcia, J. P.; Beingesser, J.; Fisher, D. J.; Sayeed, S.; McClane, B. A.; Posthaus, H.; Uzal, F. A.

    2012-01-01

    Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch’s postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24 h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24 h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis. PMID:22296994

  2. Botulinum Toxin Type a Injection, Followed by Home-Based Functional Training for Upper Limb Hemiparesis after Stroke

    ERIC Educational Resources Information Center

    Takekawa, Toru; Kakuda, Wataru; Taguchi, Kensuke; Ishikawa, Atsushi; Sase, Yousuke; Abo, Masahiro

    2012-01-01

    Botulinum toxin type A (BoNT-A) has been reported to be an effective treatment for limb spasticity after stroke. However, the reduction in the spasticity after BoNT-A injection alone does not ensure an improvement in the active motor function of the affected limb. The aim of this study was to clarify the clinical effects of a BoNT-A injection,…

  3. Comprehensive comparative-genomic analysis of Type 2 toxin-antitoxin systems and related mobile stress response systems in prokaryotes

    PubMed Central

    Makarova, Kira S; Wolf, Yuri I; Koonin, Eugene V

    2009-01-01

    Background The prokaryotic toxin-antitoxin systems (TAS, also referred to as TA loci) are widespread, mobile two-gene modules that can be viewed as selfish genetic elements because they evolved mechanisms to become addictive for replicons and cells in which they reside, but also possess "normal" cellular functions in various forms of stress response and management of prokaryotic population. Several distinct TAS of type 1, where the toxin is a protein and the antitoxin is an antisense RNA, and numerous, unrelated TAS of type 2, in which both the toxin and the antitoxin are proteins, have been experimentally characterized, and it is suspected that many more remain to be identified. Results We report a comprehensive comparative-genomic analysis of Type 2 toxin-antitoxin systems in prokaryotes. Using sensitive methods for distant sequence similarity search, genome context analysis and a new approach for the identification of mobile two-component systems, we identified numerous, previously unnoticed protein families that are homologous to toxins and antitoxins of known type 2 TAS. In addition, we predict 12 new families of toxins and 13 families of antitoxins, and also, predict a TAS or TAS-like activity for several gene modules that were not previously suspected to function in that capacity. In particular, we present indications that the two-gene module that encodes a minimal nucleotidyl transferase and the accompanying HEPN protein, and is extremely abundant in many archaea and bacteria, especially, thermophiles might comprise a novel TAS. We present a survey of previously known and newly predicted TAS in 750 complete genomes of archaea and bacteria, quantitatively demonstrate the exceptional mobility of the TAS, and explore the network of toxin-antitoxin pairings that combines plasticity with selectivity. Conclusion The defining properties of the TAS, namely, the typically small size of the toxin and antitoxin genes, fast evolution, and extensive horizontal mobility

  4. Characterization of selectivity and pharmacophores of type 1 sea anemone toxins by screening seven Na(v) sodium channel isoforms.

    PubMed

    Zaharenko, André Junqueira; Schiavon, Emanuele; Ferreira, Wilson Alves; Lecchi, Marzia; de Freitas, José Carlos; Richardson, Michael; Wanke, Enzo

    2012-03-01

    During their evolution, animals have developed a set of cysteine-rich peptides capable of binding various extracellular sites of voltage-gated sodium channels (VGSC). Sea anemone toxins that target VGSCs delay their inactivation process, but little is known about their selectivities. Here we report the investigation of three native type 1 toxins (CGTX-II, δ-AITX-Bcg1a and δ-AITX-Bcg1b) purified from the venom of Bunodosoma cangicum. Both δ-AITX-Bcg1a and δ-AITX-Bcg1b toxins were fully sequenced. The three peptides were evaluated by patch-clamp technique among Nav1.1-1.7 isoforms expressed in mammalian cell lines, and their preferential targets are Na(v)1.5>1.6>1.1. We also evaluated the role of some supposedly critical residues in the toxins which would interact with the channels, and observed that some substitutions are not critical as expected. In addition, CGTX-II and δ-AITX-Bcg1a evoke different shifts in activation/inactivation Boltzmann curves in Nav1.1 and 1.6. Moreover, our results suggest that the interaction region between toxins and VGSCs is not restricted to the supposed site 3 (S3-S4 linker of domain IV), and this may be a consequence of distinct surface of contact of each peptide vs. targeted channel. Our data suggest that the contact surfaces of each peptide may be related to their surface charges, as CGTX-II is more positive than δ-AITX-Bcg1a and δ-AITX-Bcg1b. PMID:21802465

  5. Differential response of the human renal proximal tubular epithelial cell line HK-2 to Shiga toxin types 1 and 2.

    PubMed

    Lentz, Erin K; Leyva-Illades, Dinorah; Lee, Moo-Seung; Cherla, Rama P; Tesh, Vernon L

    2011-09-01

    Shiga toxins (Stxs) are expressed by the enteric pathogens Shigella dysenteriae serotype 1 and certain serotypes of Escherichia coli. Stx-producing bacteria cause bloody diarrhea with the potential to progress to acute renal failure. Stxs are potent protein synthesis inhibitors and are the primary virulence factors responsible for renal damage that may follow diarrheal disease. We explored the use of the immortalized human proximal tubule epithelial cell line HK-2 as an in vitro model of Stx-induced renal damage. We showed that these cells express abundant membrane Gb(3) and are differentially susceptible to the cytotoxic action of Stxs, being more sensitive to Shiga toxin type 1 (Stx1) than to Stx2. At early time points (24 h), HK-2 cells were significantly more sensitive to Stxs than Vero cells; however, by 72 h, Vero cell monolayers were completely destroyed while some HK-2 cells survived toxin challenge, suggesting that a subpopulation of HK-2 cells are relatively toxin resistant. Fluorescently labeled Stx1 B subunits localized to both lysosomal and endoplasmic reticulum (ER) compartments in HK-2 cells, suggesting that differences in intracellular trafficking may play a role in susceptibility to Stx-mediated cytotoxicity. Although proinflammatory cytokines were not upregulated by toxin challenge, Stx2 selectively induced the expression of two chemokines, macrophage inflammatory protein-1α (MIP-1α) and MIP-1β. Stx1 and Stx2 differentially activated components of the ER stress response in HK-2 cells. Finally, we demonstrated significant poly(ADP-ribose) polymerase (PARP) cleavage after exposure to Stx1 or Stx2. However, procaspase 3 cleavage was undetectable, suggesting that HK-2 cells may undergo apoptosis in response to Stxs in a caspase 3-independent manner. PMID:21708996

  6. Location of the Bombyx mori aminopeptidase N type 1 binding site on Bacillus thuringiensis Cry1Aa toxin.

    PubMed

    Atsumi, Shogo; Mizuno, Eri; Hara, Hirotaka; Nakanishi, Kazuko; Kitami, Madoka; Miura, Nami; Tabunoki, Hiroko; Watanabe, Ayako; Sato, Ryoichi

    2005-07-01

    We analyzed the binding site on Cry1Aa toxin for the Cry1Aa receptor in Bombyx mori, 115-kDa aminopeptidase N type 1 (BmAPN1) (K. Nakanishi, K. Yaoi, Y. Nagino, H. Hara, M. Kitami, S. Atsumi, N. Miura, and R. Sato, FEBS Lett. 519:215-220, 2002), by using monoclonal antibodies (MAbs) that block binding between the binding site and the receptor. First, we produced a series of MAbs against Cry1Aa and obtained two MAbs, MAbs 2C2 and 1B10, that were capable of blocking the binding between Cry1Aa and BmAPN1 (blocking MAbs). The epitope of the Fab fragments of MAb 2C2 overlapped the BmAPN1 binding site, whereas the epitope of the Fab fragments of MAb 1B10 did not overlap but was located close to the binding site. Using three approaches for epitope mapping, we identified two candidate epitopes for the blocking MAbs on Cry1Aa. We constructed two Cry1Aa toxin mutants by substituting a cysteine on the toxin surface at each of the two candidate epitopes, and the small blocking molecule N-(9-acridinyl)maleimide (NAM) was introduced at each cysteine substitution to determine the true epitope. The Cry1Aa mutant with NAM bound to Cys582 did not bind either of the two blocking MAbs, suggesting that the true epitope for each of the blocking MAbs was located at the site containing Val582, which also consisted of 508STLRVN513 and 582VFTLSAHV589. These results indicated that the BmAPN1 binding site overlapped part of the region blocked by MAb 2C2 that was close to but excluded the actual epitope of MAb 2C2 on domain III of Cry1Aa toxin. We also discuss another area on Cry1Aa toxin as a new candidate site for BmAPN1 binding. PMID:16000811

  7. Location of the Bombyx mori Aminopeptidase N Type 1 Binding Site on Bacillus thuringiensis Cry1Aa Toxin

    PubMed Central

    Atsumi, Shogo; Mizuno, Eri; Hara, Hirotaka; Nakanishi, Kazuko; Kitami, Madoka; Miura, Nami; Tabunoki, Hiroko; Watanabe, Ayako; Sato, Ryoichi

    2005-01-01

    We analyzed the binding site on Cry1Aa toxin for the Cry1Aa receptor in Bombyx mori, 115-kDa aminopeptidase N type 1 (BmAPN1) (K. Nakanishi, K. Yaoi, Y. Nagino, H. Hara, M. Kitami, S. Atsumi, N. Miura, and R. Sato, FEBS Lett. 519:215-220, 2002), by using monoclonal antibodies (MAbs) that block binding between the binding site and the receptor. First, we produced a series of MAbs against Cry1Aa and obtained two MAbs, MAbs 2C2 and 1B10, that were capable of blocking the binding between Cry1Aa and BmAPN1 (blocking MAbs). The epitope of the Fab fragments of MAb 2C2 overlapped the BmAPN1 binding site, whereas the epitope of the Fab fragments of MAb 1B10 did not overlap but was located close to the binding site. Using three approaches for epitope mapping, we identified two candidate epitopes for the blocking MAbs on Cry1Aa. We constructed two Cry1Aa toxin mutants by substituting a cysteine on the toxin surface at each of the two candidate epitopes, and the small blocking molecule N-(9-acridinyl)maleimide (NAM) was introduced at each cysteine substitution to determine the true epitope. The Cry1Aa mutant with NAM bound to Cys582 did not bind either of the two blocking MAbs, suggesting that the true epitope for each of the blocking MAbs was located at the site containing Val582, which also consisted of 508STLRVN513 and 582VFTLSAHV589. These results indicated that the BmAPN1 binding site overlapped part of the region blocked by MAb 2C2 that was close to but excluded the actual epitope of MAb 2C2 on domain III of Cry1Aa toxin. We also discuss another area on Cry1Aa toxin as a new candidate site for BmAPN1 binding. PMID:16000811

  8. Characterization of an organism that produces type E botulinal toxin but which resembles Clostridium butyricum from the feces of an infant with type E botulism.

    PubMed

    McCroskey, L M; Hatheway, C L; Fenicia, L; Pasolini, B; Aureli, P

    1986-01-01

    The apparent causative organism from the only reported case of type E infant botulism was isolated and characterized. Except for its ability to produce type E botulinal toxin, this organism (strain 5262) would be unquestionably identified as Clostridium butyricum. This is the second time an organism resembling a defined Clostridium species other than a member of the C. botulinum group has been implicated in infant botulism. PMID:3517043

  9. Identification of Human-Pathogenic Strains of Shiga Toxin-Producing Escherichia coli from Food by a Combination of Serotyping and Molecular Typing of Shiga Toxin Genes▿

    PubMed Central

    Beutin, Lothar; Miko, Angelika; Krause, Gladys; Pries, Karin; Haby, Sabine; Steege, Katja; Albrecht, Nadine

    2007-01-01

    We examined 219 Shiga toxin-producing Escherichia coli (STEC) strains from meat, milk, and cheese samples collected in Germany between 2005 and 2006. All strains were investigated for their serotypes and for genetic variants of Shiga toxins 1 and 2 (Stx1 and Stx2). stx1 or variant genes were detected in 88 (40.2%) strains and stx2 and variants in 177 (80.8%) strains. Typing of stx genes was performed by stx-specific PCRs and by analysis of restriction fragment length polymorphisms (RFLP) of PCR products. Major genotypes of the Stx1 (stx1, stx1c, and stx1d) and the Stx2 (stx2, stx2d, stx2-O118, stx2e, and stx2g) families were detected, and multiple types of stx genes coexisted frequently in STEC strains. Only 1.8% of the STEC strains from food belonged to the classical enterohemorrhagic E. coli (EHEC) types O26:H11, O103:H2, and O157:H7, and only 5.0% of the STEC strains from food were positive for the eae gene, which is a virulence trait of classical EHEC. In contrast, 95 (43.4%) of the food-borne STEC strains carried stx2 and/or mucus-activatable stx2d genes, an indicator for potential high virulence of STEC for humans. Most of these strains belonged to serotypes associated with severe illness in humans, such as O22:H8, O91:H21, O113:H21, O174:H2, and O174:H21. stx2 and stx2d STEC strains were found frequently in milk and beef products. Other stx types were associated more frequently with pork (stx2e), lamb, and wildlife meat (stx1c). The combination of serotyping and stx genotyping was found useful for identification and for assignment of food-borne STEC to groups with potential lower and higher levels of virulence for humans. PMID:17557838

  10. [INJECTION OF BOTULINUM TOXIN TYPE A IN THE BLADDER DETRUSOR AND SUBMUCOSA IN PATIENTS WITH OVERACTIVE BLADDER WITHOUT DETRUSOR OVERACTIVITY].

    PubMed

    Krivoborodov, G G; Tur, E I; Efremov, N S

    2015-01-01

    The objective of the study was to compare the efficacy and safety of injections of botulinum toxin type A in the submucosal layer of the bladder and in detrusor in patients who were refractory to anticholinergic therapy of overactive bladder without detrusor overactivity. 100 U botulinum toxin type A was diluted in 10 ml of 0.9% saline and injected with 0.5 ml (5 units) of this solution in 20 points of the bladder (the back and side walls except Letto triangle). In twenty-two patients (the first group) botulinum toxin was injected into the submucosal layer of the bladder, while in 34 patients (second group) - into the detrusor. In the first group after 1 and 3 months 3 (14%) patients and after 6 months 2 (9%) patients had positive treatment outcomes (improvement of symptoms in more than 50%). In 22 (65%) of the 34 patients of the second group positive results were observed at 1 and 3 months and in 17 (50%) - at 6 months. After 9 months, all patients had a relapse of urgent and frequent urination. Difficulties in emptying the bladder were observed in three (9%) of the second group patients who had to resort to periodic self-catheterization for 2-20 weeks. The obtained results allow us to state that the injections of 100 U of botulinum toxin type A in the submucosal layer of the bladder are ineffective in patients with overactive bladder without detrusor overactivity, whereas injections in the detrusor lead to a statistically significant improvement in symptoms of urgent and frequent urination for 6 months. PMID:26237802

  11. Nonallergic Eyelid Edema After Botulinum Toxin Type A Injection: Case Report and Review of Literature.

    PubMed

    Chang, Yin-Shuo; Chang, Chang-Cheng; Shen, Jen-Hsiang; Chen, Yu-Tsung; Chan, Karen Kar-Wun

    2015-09-01

    Periocular botulinum toxin type A (BoNTA) injections are generally safe. Ptosis is the most common adverse effect, whereas eyelid edema is rarely reported. There is no consensus on the latter's incidence, clinical course, or treatment strategy. Here we managed a 59-year-old woman who received BoNTA injections to her forehead, glabella, and eye corner. At 3-day follow-up, she presented with painless, nonpruritic, bilateral periorbital edema, and erythema. Preliminary diagnosis was a local allergic reaction, and topical corticosteroid was administered, but upon lack of improvement, edema secondary to venous and lymphatic congestion was hypothesized, and she was advised to apply hot pads over her eyes, blink frequently, and massage the area. Her eyelid edema resolved 2 weeks later. At 4-month follow-up, the patient requested and received another course of BoNTA at half the dose. Frequent blinking was instructed, and the patient reported a satisfactory outcome with no adverse effects. In our literature review, incidence of BoNTA-induced eyelid edema was 1.4% and showed Asian tendency. Although rare, BoNTA-induced periorbital edema is self-limiting, and normally resolves in 2 to 4 weeks without medical treatment. Patients at risk for edema, including Asian ethnicity, dermatochalasis, and poor periocular muscle tone, are advised to receive injections at half the dosage. Examination of the function and tone of the orbicularis oculi and levator palpebrae superioris muscles before treatment is recommended, and application of hot pads over the eyes, frequent blinking in the morning, and self-massage of the affected area to increase venous return have demonstrated to improve outcome. PMID:26402825

  12. The effects of electrical stimulation exercise on muscles injected with botulinum toxin type-A (botox).

    PubMed

    Fortuna, Rafael; Horisberger, Monika; Vaz, Marco Aurélio; Van der Marel, Robert; Herzog, Walter

    2013-01-01

    Botulinum toxin type A (BTX-A) is a frequently used treatment modality for a variety of neuromuscular disorders. It acts by preventing acetylcholine release at the motor nerve endings, inducing muscle paralysis. Although considered safe, studies suggest that BTX-A injections create adverse effects on target and non-target muscles. We speculate that these adverse effects are reduced by direct electrical stimulation (ES) exercising of muscles. The aims were to determine the effects of ES exercise on strength, mass, and contractile material in BTX-A injected muscles, and to investigate if BTX-A injections affect non-target muscles. Seventeen New Zealand White (NZW) rabbits were divided into three groups: (1) Control group received saline injections; (2) BTX-A group received monthly BTX-A (3.5 U/kg) injections into the quadriceps for six months and (3) BTX-A+ES group received monthly BTX-A injections and ES exercise three times a week for six months. Outcome measures included knee extensor torque, muscle mass, and contractile material percentage area in injected and contralateral, non-injected quadriceps. Glycogen depletion and direct muscle stimulation were used to assess possible muscle inhibition in non-injected quadriceps. ES exercise partially prevented muscle weakness, atrophy, and contractile material loss in injected muscles, and mostly prevented muscle degeneration in contralateral, non-injected muscles. Non-injected muscles of BTX-A+ES group showed higher force with direct muscle compared to nerve stimulation, and retained glycogen following the depletion protocol, suggesting that BTX-A inhibited activation in non-target muscles. We conclude that ES exercise provides some protection from degeneration to target and non-target muscles during BTX-A treatments. PMID:23122225

  13. Botulinum toxin type A for neuropathic pain in patients with spinal cord injury

    PubMed Central

    Han, Zee‐A; Song, Dae Heon; Oh, Hyun‐Mi

    2016-01-01

    Objective To evaluate the analgesic effect of botulinum toxin type A (BTX‐A) on patients with spinal cord injury‐associated neuropathic pain. Methods The effect of BTX‐A on 40 patients with spinal cord injury‐associated neuropathic pain was investigated using a randomized, double‐blind, placebo‐controlled design. A 1‐time subcutaneous BTX‐A (200U) injection was administered to the painful area. Visual analogue scale (VAS) scores (0–100mm), the Korean version of the short‐form McGill Pain Questionnaire, and the World Health Organization WHOQOL‐BREF quality of life assessment were evaluated prior to treatment and at 4 and 8 weeks after the injection. Results At 4 and 8 weeks after injection, the VAS score for pain was significantly reduced by 18.6 ± 16.8 and 21.3 ± 26.8, respectively, in the BTX‐A group, whereas it was reduced by 2.6 ± 14.6 and 0.3 ± 19.5, respectively, in the placebo group. The pain relief was associated with preservation of motor or sensory function below the neurological level of injury. Among the responders in the BTX‐A group, 55% and 45% reported pain relief of 20% or greater at 4 and 8 weeks, respectively, after the injection, whereas only 15% and 10% of the responders in the placebo group reported a similar level of pain relief. Improvements in the score for the physical health domain of the WHOQOL‐BREF in the BTX‐A group showed a marginal trend toward significance (p = 0.0521) at 4 weeks after the injection. Interpretation These results indicate that BTX‐A may reduce intractable chronic neuropathic pain in patients with spinal cord injury. Ann Neurol 2016;79:569–578 PMID:26814620

  14. Botulinum toxin type A as an adjunct in postoperative pain management in dogs undergoing radical mastectomy.

    PubMed

    Vilhegas, S; Cassu, R N; Barbero, R C; Crociolli, G C; Rocha, T L A; Gomes, D R

    2015-10-17

    The aim of this randomised placebo-controlled, observer-blinded study was to evaluate the analgesic effects of botulinum toxin type A (BoNT-A) as an adjunct for postoperative pain control in dogs. Sixteen dogs undergoing bilateral radical mastectomy for treatment of mammary tumours were enrolled. Twenty-four hours before surgery, the subjects were distributed into two groups of eight dogs each: 7 iu/kg BoNT-A (BoNT-A) or saline (Control) was administered subcutaneously in each mammary gland. Following sedation with intramuscular 0.03 mg/kg acepromazine and 0.3 mg/kg morphine, anaesthesia was induced intravenously with 4 mg/kg propofol and maintained with isoflurane/O2. Postoperative analgesia was evaluated for 72 hours after extubation using the Visual Analogue Scale (VAS) and modified Glasgow Composite Measure Pain Scale (modified-GCMPS). Rescue analgesia was provided with intramuscular morphine (0.5 mg/kg). Data were analysed using analysis of variance, Tukey's test, Mann-Whitney U test and Friedman test (P<0.05). The pain scores were significantly lower in the BoNT-A than in the Control from 8 hours to 60 hours and from 12 hours to 60 hours after extubation, based on the VAS and modified-GCMPS, respectively. Rescue analgesia was required by significantly more dogs in the Control (7/8) compared with the BoNT-A (2/8) (P=0.022). Pre-emptive BoNT-A appears to be effective as an adjuvant for postoperative pain management in dogs undergoing bilateral radical mastectomy. PMID:26446882

  15. Antinociceptive Effects of Botulinum Toxin Type A on Trigeminal Neuropathic Pain.

    PubMed

    Yang, K Y; Kim, M J; Ju, J S; Park, S K; Lee, C G; Kim, S T; Bae, Y C; Ahn, D K

    2016-09-01

    Previous studies have demonstrated that botulinum toxin type A (BoNT-A) attenuates orofacial nociception. However, there has been no evidence of the participation of the voltage-gated sodium channels (Navs) in the antinociceptive mechanisms of BoNT-A. This study investigated the cellular mechanisms underlying the antinociceptive effects of BoNT-A in a male Sprague-Dawley rat model of trigeminal neuropathic pain produced by malpositioned dental implants. The left mandibular second molar was extracted under anesthesia, followed by a miniature dental implant placement to induce injury to the inferior alveolar nerve. Mechanical allodynia was monitored after subcutaneous injection of BoNT-A at 3, 7, or 12 d after malpositioned dental implant surgery. Subcutaneous injections of 1 or 3 U/kg of BoNT-A on postoperative day 3 significantly attenuated mechanical allodynia, although 0.3 U/kg of BoNT-A did not affect the air-puff threshold. A single injection of 3 U/kg of BoNT-A produced prolonged antiallodynic effects over the entire experimental period. Treatment with BoNT-A on postoperative days 7 and 12, when pain had already been established, also produced prolonged antiallodynic effects. Double treatments with 1 U/kg of BoNT-A produced prolonged, more antiallodynic effects as compared with single treatments. Subcutaneous administration of 3 U/kg of BoNT-A significantly inhibited the upregulation of Nav isoform 1.7 (Nav1.7) expression in the trigeminal ganglion in the nerve-injured animals. These results suggest that antinociceptive effects of BoNT-A are mediated by an inhibition of upregulated Nav1.7 expression in the trigeminal ganglion. BoNT-A is therefore a potential new therapeutic agent for chronic pain control, including neuropathic pain. PMID:27418174

  16. Vaccination by cholera toxin conjugated to a herpes simplex virus type 2 glycoprotein D peptide.

    PubMed

    Drew, M D; Estrada-Correa, A; Underdown, B J; McDermott, M R

    1992-09-01

    Immunization of BALB/cJ mice with a peptide corresponding to residues 1 to 23 of glycoprotein D [gD(1-23)] from herpes simplex virus type 2 (HSV-2) elicits antibody responses which correlate with protection against lethal HSV-2 infection. In the present study, we examined the ability of cholera toxin (CTX) to act as an immunogenic carrier for gD(1-23). The number of gD(1-23) residues conjugated to CTX affected its binding to GM1 ganglioside and physiological toxicity, both of which are factors affecting oral immunogenicity. The antibody response elicited after intraperitoneal (i.p.) immunization with the CTX-gD(1-23) conjugate was protective against a lethal i.p. challenge with HSV-2. In other experiments, mice were immunized i.p. on day 0 and subsequent immunizations conducted on days 14 and 28 were administered either intragastrically or intravaginally (i.vag.). Intraperitoneal priming followed by either i.p or intragastric boosting resulted in anti-HSV-2 antibodies in vaginal washings and in protection against a lethal i.vag. challenge with HSV-2. Intraperitoneal priming followed by i.vag. boosting did not elicit anti-HSV-2 antibodies in vaginal washings and did not protect mice against a lethal i.vag. challenge with HSV-2. These results suggest that CTX can act as a systemic and an oral delivery molecule for the covalently linked gD(1-23) peptide and that such conjugates can elicit protective immune responses against systemic and genital HSV-2 infection. PMID:1383408

  17. Cholera toxin conjugates for intragastric vaccination against herpes simplex virus type 2.

    PubMed

    Drew, M D; Estrada, A E; Underdown, B J; McDermott, M R

    1992-01-01

    In this study, we tested the hypothesis that enteric immunization with cholera toxin (CTX) conjugated to glycoprotein D (gD) of herpes simplex virus type 2 (HSV-2) or a peptide corresponding to residues (1-23) of gD (gD(1-23)) would induce relevant antiviral immunity. Intraperitoneal (IP) immunization of mice with CTX-gD(1-23) conjugate induced anti-HSV-2 sera antibody responses which correlated with protection from a lethal IP challenge with HSV-2. Intragastric (IG) immunization of mice with the same conjugate or a CTX-gD conjugate did not result in measurable anti-HSV-2 responses in sera or vaginal washings and only small numbers of anti-HSV-2 antibody-secreting cells (ASC) were found in intestinal lamina propria cell and splenocyte preparations. In comparison, anti-CTX responses were detected in sera and vaginal washings after IG immunization with CTX and anti-CTX ASC in lamina propria cell preparations accounted for 5-10% of total ASC detected at this site. No significant differences in the survival of mice immunized with the conjugates were noted after a lethal intravaginal (IVAG) challenge with HSV-2. The poor enteric immunogenicity of gD(1-23) and gD conjugated to CTX was attributable to proteolysis in the gastrointestinal tract. These results indicate that although peptide-CTX conjugates can induce protective immune responses when administered parenterally, it may not be feasible to use peptides as the basis of an oral vaccine unless methods are developed to protect these antigens from degradation in the gastrointestinal tract. PMID:1503890

  18. High-resolution crystal structure of HA33 of botulinum neurotoxin type B progenitor toxin complex.

    PubMed

    Lee, Kwangkook; Lam, Kwok-Ho; Kruel, Anna Magdalena; Perry, Kay; Rummel, Andreas; Jin, Rongsheng

    2014-04-01

    Botulinum neurotoxins (BoNTs) are produced as progenitor toxin complexes (PTCs) by Clostridium botulinum. The PTCs are composed of BoNT and non-toxic neurotoxin-associated proteins (NAPs), which serve to protect and deliver BoNT through the gastrointestinal tract in food borne botulism. HA33 is a key NAP component that specifically recognizes host carbohydrates and helps enrich PTC on the intestinal lumen preceding its transport across the epithelial barriers. Here, we report the crystal structure of HA33 of type B PTC (HA33/B) in complex with lactose at 1.46Å resolution. The structural comparisons among HA33 of serotypes A-D reveal two different HA33-glycan interaction modes. The glycan-binding pockets on HA33/A and B are more suitable to recognize galactose-containing glycans in comparison to the equivalent sites on HA33/C and D. On the contrary, HA33/C and D could potentially recognize Neu5Ac as an independent receptor, whereas HA33/A and B do not. These findings indicate that the different oral toxicity and host susceptibility observed among different BoNT serotypes could be partly determined by the serotype-specific interaction between HA33 and host carbohydrate receptors. Furthermore, we have identified a key structural water molecule that mediates the HA33/B-lactose interactions. It provides the structural basis for development of new receptor-mimicking compounds, which have enhanced binding affinity with HA33 through their water-displacing moiety. PMID:24631690

  19. Comparisons of native Shiga toxins (Stxs) type 1 and 2 with chimeric toxins indicate that the source of the binding subunit dictates degree of toxicity.

    PubMed

    Russo, Lisa M; Melton-Celsa, Angela R; Smith, Michael J; O'Brien, Alison D

    2014-01-01

    Shiga toxin (Stx)-producing E. coli (STEC) cause food-borne outbreaks of hemorrhagic colitis. The main virulence factor expressed by STEC, Stx, is an AB5 toxin that has two antigenically distinct forms, Stx1a and Stx2a. Although Stx1a and Stx2a bind to the same receptor, globotriaosylceramide (Gb3), Stx2a is more potent than Stx1a in mice, whereas Stx1a is more cytotoxic than Stx2a in cell culture. In this study, we used chimeric toxins to ask what the relative contribution of individual Stx subunits is to the differential toxicity of Stx1a and Stx2a in vitro and in vivo. Chimeric stx1/stx2 operons were generated by PCR such that the coding regions for the A2 and B subunits of one toxin were combined with the coding region for the A1 subunit of the heterologous toxin. The toxicities of purified Stx1a, Stx2a, and the chimeric Stxs were determined on Vero and HCT-8 cell lines, while polarized HCT-8 cell monolayers grown on permeable supports were used to follow toxin translocation. In all in vitro assays, the activity of the chimeric toxin correlated with that of the parental toxin from which the B subunit originated. The origin of the native B subunit also dictated the 50% lethal dose of toxin after intraperitoneal intoxication of mice; however, the chimeric Stxs exhibited reduced oral toxicity and pH stability compared to Stx1a and Stx2a. Taken together, these data support the hypothesis that the differential toxicity of the chimeric toxins for cells and mice is determined by the origin of the B subunit. PMID:24671194

  20. [Effect of immunomodulators on resistance to gas gangrene. The enhanced resistance of white mice to perfringens toxin type A as affected by prodigiozan].

    PubMed

    Konikova, R E; Stepanov, A V; Sviridov, L P

    1986-02-01

    Experiments on 575 noninbred white mice have revealed that the nonspecific resistance of the animals to type A C. perfringens toxin can be enhanced by the administration of Prodigiosan, a commercial immunostimulating agent. Prodigiosan, introduced in 3-4 injections (the last one made 24 hours before intoxication) has been found to enhance the resistance of the animals to the subcutaneous injection of type A C. perfringens toxin by 40-60% and to its intraperitoneal injection by 60-97%. PMID:2870596

  1. Non-oxidative, controlled exfoliation of graphite in aqueous medium.

    PubMed

    Srivastava, Pawan Kumar; Yadav, Premlata; Ghosh, Subhasis

    2016-08-25

    We present a simple, non-oxidative and controlled method to synthesize graphene monolayers by exfoliation in water from different solid carbon sources, such as highly ordered pyrolytic graphite and low density graphite. Any water based method is highly desirable due to several attractive features, such as environmental friendliness, low cost and wide compatibility with other water based processes. We show that thin graphene layers can be exfoliated controllably and reproducibly by varying different parameters during exfoliation in aqueous medium. It has been possible to obtain high quality graphene monolayers with a yield of ∼2.45 wt%, which can be increased up to 16.6 wt% by recycling the sediments. Field effect transistors based on exfoliated graphene monolayers have shown n-type doping and a high carrier mobility of 4500 cm(2) V(-1) s(-1) at room temperature and ∼20 000 cm(2) V(-1) s(-1) at low temperature. Density functional calculations corroborate the infrared spectroscopic results and also indicate that the charge transfer preferentially occurs from water molecules to the graphene sheets resulting in n-type doping. We anticipate that exfoliation of high quality graphene layers in aqueous medium would open up a pathway for various graphene based electronic and biological applications. PMID:27523721

  2. Spatio-temporal dynamics of Fusarium head blight and Trichothecene toxin types in Canada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many parts of the world Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB), a disease of cereal crops that adversely affects crop yield, food safety, and animal health. We previously demonstrated population structure associated with differences in trichothecene toxin t...

  3. Effects of Shiga Toxin Type 2 on Maternal and Fetal Status in Rats in the Early Stage of Pregnancy

    PubMed Central

    Sacerdoti, Flavia; Amaral, María M.; Zotta, Elsa; Franchi, Ana M.; Ibarra, Cristina

    2014-01-01

    Shiga toxin type 2 (Stx2), a toxin secreted by Shiga toxin-producing Escherichia coli (STEC), could be one of the causes of maternal and fetal morbimortality not yet investigated. In this study, we examined the effects of Stx2 in rats in the early stage of pregnancy. Sprague-Dawley pregnant rats were intraperitoneally (i.p.) injected with sublethal doses of Stx2, 0.25 and 0.5 ng Stx2/g of body weight (bwt), at day 8 of gestation (early postimplantation period of gestation). Maternal weight loss and food and water intake were analyzed after Stx2 injection. Another group of rats were euthanized and uteri were collected at different times to evaluate fetal status. Immunolocalization of Stx2 in uterus and maternal kidneys was analyzed by immunohistochemistry. The presence of Stx2 receptor (globotriaosylceramide, Gb3) in the uteroplacental unit was observed by thin layer chromatography (TLC). Sublethal doses of Stx2 in rats caused maternal weight loss and pregnancy loss. Stx2 and Gb3 receptor were localized in decidual tissues. Stx2 was also immunolocalized in renal tissues. Our results demonstrate that Stx2 leads to pregnancy loss and maternal morbidity in rats in the early stage of pregnancy. This study highlights the possibility of human pregnancy loss and maternal morbidity mediated by Stx2. PMID:25157355

  4. Shiga toxin type-2 (Stx2) induces glutamate release via phosphoinositide 3-kinase (PI3K) pathway in murine neurons

    PubMed Central

    Obata, Fumiko; Hippler, Lauren M.; Saha, Progyaparamita; Jandhyala, Dakshina M.; Latinovic, Olga S.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) can cause central nervous system (CNS) damage resulting in paralysis, seizures, and coma. The key STEC virulence factors associated with systemic illness resulting in CNS impairment are Shiga toxins (Stx). While neurons express the Stx receptor globotriaosylceramide (Gb3) in vivo, direct toxicity to neurons by Stx has not been studied. We used murine neonatal neuron cultures to study the interaction of Shiga toxin type 2 (Stx2) with cell surface expressed Gb3. Single molecule imaging three dimensional STochastic Optical Reconstruction Microscopy—Total Internal Reflection Fluorescence (3D STORM-TIRF) allowed visualization and quantification of Stx2-Gb3 interactions. Furthermore, we demonstrate that Stx2 increases neuronal cytosolic Ca2+, and NMDA-receptor inhibition blocks Stx2-induced Ca2+ influx, suggesting that Stx2-mediates glutamate release. Phosphoinositide 3-kinase (PI3K)-specific inhibition by Wortmannin reduces Stx2-induced intracellular Ca2+ indicating that the PI3K signaling pathway may be involved in Stx2-associated glutamate release, and that these pathways may contribute to CNS impairment associated with STEC infection. PMID:26236186

  5. C-type natriuretic peptide modulates quorum sensing molecule and toxin production in Pseudomonas aeruginosa.

    PubMed

    Blier, Anne-Sophie; Veron, Wilfried; Bazire, Alexis; Gerault, Eloïse; Taupin, Laure; Vieillard, Julien; Rehel, Karine; Dufour, Alain; Le Derf, Franck; Orange, Nicole; Hulen, Christian; Feuilloley, Marc G J; Lesouhaitier, Olivier

    2011-07-01

    Pseudomonas aeruginosa coordinates its virulence expression and establishment in the host in response to modification of its environment. During the infectious process, bacteria are exposed to and can detect eukaryotic products including hormones. It has been shown that P. aeruginosa is sensitive to natriuretic peptides, a family of eukaryotic hormones, through a cyclic nucleotide-dependent sensor system that modulates its cytotoxicity. We observed that pre-treatment of P. aeruginosa PAO1 with C-type natriuretic peptide (CNP) increases the capacity of the bacteria to kill Caenorhabditis elegans through diffusive toxin production. In contrast, brain natriuretic peptide (BNP) did not affect the capacity of the bacteria to kill C. elegans. The bacterial production of hydrogen cyanide (HCN) was enhanced by both BNP and CNP whereas the production of phenazine pyocyanin was strongly inhibited by CNP. The amount of 2-heptyl-4-quinolone (HHQ), a precursor to 2-heptyl-3-hydroxyl-4-quinolone (Pseudomonas quinolone signal; PQS), decreased after CNP treatment. The quantity of 2-nonyl-4-quinolone (HNQ), another quinolone which is synthesized from HHQ, was also reduced after CNP treatment. Conversely, both BNP and CNP significantly enhanced bacterial production of acylhomoserine lactone (AHL) [e.g. 3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and butanoylhomoserine lactone (C4-HSL)]. These results correlate with an induction of lasI transcription 1 h after bacterial exposure to BNP or CNP. Concurrently, pre-treatment of P. aeruginosa PAO1 with either BNP or CNP enhanced PAO1 exotoxin A production, via a higher toxA mRNA level. At the same time, CNP led to elevated amounts of algC mRNA, indicating that algC is involved in C. elegans killing. Finally, we observed that in PAO1, Vfr protein is essential to the pro-virulent effect of CNP whereas the regulator PtxR supports only a part of the CNP pro-virulent activity. Taken together, these data reinforce the hypothesis that during

  6. Enhanced type 1alpha metabotropic glutamate receptor-stimulated phosphoinositide signaling after pertussis toxin treatment.

    PubMed

    Carruthers, A M; Challiss, R A; Mistry, R; Saunders, R; Thomsen, C; Nahorski, S R

    1997-09-01

    The regulation of phosphoinositide hydrolysis by the type 1alpha metabotropic glutamate receptor (mGluR1alpha) was investigated in stably transfected baby hamster kidney (BHK) cells. Incubation of the cells with L-glutamate, quisqualate, and 1-aminocyclopentane-1S, 3R-dicarboxylic acid resulted in a marked accumulation of [3H]inositol monophosphate (InsP1) and inositol-1,4,5-trisphosphate [Ins(1,4,5)P3] mass in a time- and concentration-dependent manner. Pretreatment of BHK-mGluR1alpha cells with pertussis toxin [ 100 ng/ml, 24 hr] led to a dramatic 12-16-fold increase in the accumulation of [3H]InsP1 and a 2-fold increase in Ins(1,4,5)P3 in the absence of added agonist. Although only very low levels (/=75%, and the EC50 shifted leftward by 65-fold [-log EC50 values (molar), 7.26 +/- 0.23 versus 5.45 +/- 0.07; n = 4) in PTX-treated compared with control cells. In contrast, antagonist effects on agonist-stimulated [3H]InsP1 responses were similar in control and PTX-treated BHK-mGluR1alpha cells. These changes in the concentration-effect curves for mGluR agonists are consistent with a model in which the receptor associates with PTX-sensitive inhibitory (Gi/o) and PTX-insensitive stimulatory (Gq/11) G proteins that can each influence PIC activity. The present observations are consistent with a dual regulation of mGluR1alpha-mediated PIC activity that could be fundamental in

  7. C-type natriuretic peptide modulates quorum sensing molecule and toxin production in Pseudomonas aeruginosa

    PubMed Central

    Blier, Anne-Sophie; Veron, Wilfried; Bazire, Alexis; Gerault, Eloïse; Taupin, Laure; Vieillard, Julien; Rehel, Karine; Dufour, Alain; Le Derf, Franck; Orange, Nicole; Hulen, Christian; Feuilloley, Marc G. J.

    2011-01-01

    Pseudomonas aeruginosa coordinates its virulence expression and establishment in the host in response to modification of its environment. During the infectious process, bacteria are exposed to and can detect eukaryotic products including hormones. It has been shown that P. aeruginosa is sensitive to natriuretic peptides, a family of eukaryotic hormones, through a cyclic nucleotide-dependent sensor system that modulates its cytotoxicity. We observed that pre-treatment of P. aeruginosa PAO1 with C-type natriuretic peptide (CNP) increases the capacity of the bacteria to kill Caenorhabditis elegans through diffusive toxin production. In contrast, brain natriuretic peptide (BNP) did not affect the capacity of the bacteria to kill C. elegans. The bacterial production of hydrogen cyanide (HCN) was enhanced by both BNP and CNP whereas the production of phenazine pyocyanin was strongly inhibited by CNP. The amount of 2-heptyl-4-quinolone (HHQ), a precursor to 2-heptyl-3-hydroxyl-4-quinolone (Pseudomonas quinolone signal; PQS), decreased after CNP treatment. The quantity of 2-nonyl-4-quinolone (HNQ), another quinolone which is synthesized from HHQ, was also reduced after CNP treatment. Conversely, both BNP and CNP significantly enhanced bacterial production of acylhomoserine lactone (AHL) [e.g. 3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and butanoylhomoserine lactone (C4-HSL)]. These results correlate with an induction of lasI transcription 1 h after bacterial exposure to BNP or CNP. Concurrently, pre-treatment of P. aeruginosa PAO1 with either BNP or CNP enhanced PAO1 exotoxin A production, via a higher toxA mRNA level. At the same time, CNP led to elevated amounts of algC mRNA, indicating that algC is involved in C. elegans killing. Finally, we observed that in PAO1, Vfr protein is essential to the pro-virulent effect of CNP whereas the regulator PtxR supports only a part of the CNP pro-virulent activity. Taken together, these data reinforce the hypothesis that during

  8. Bacterial toxins: friends or foes?

    PubMed Central

    Schmitt, C. K.; Meysick, K. C.; O'Brien, A. D.

    1999-01-01

    Many emerging and reemerging bacterial pathogens synthesize toxins that serve as primary virulence factors. We highlight seven bacterial toxins produced by well-established or newly emergent pathogenic microbes. These toxins, which affect eukaryotic cells by a variety of means, include Staphylococcus aureus alpha-toxin, Shiga toxin, cytotoxic necrotizing factor type 1, Escherichia coli heat-stable toxin, botulinum and tetanus neurotoxins, and S. aureus toxic-shock syndrome toxin. For each, we discuss the information available on its synthesis and structure, mode of action, and contribution to virulence. We also review the role certain toxins have played in unraveling signal pathways in eukaryotic cells and summarize the beneficial uses of toxins and toxoids. Our intent is to illustrate the importance of the analysis of bacterial toxins to both basic and applied sciences. PMID:10221874

  9. Brain lesions associated with clostridium perfringens type D epsilon toxin in a Holstein heifer calf.

    PubMed

    Mete, A; Garcia, J; Ortega, J; Lane, M; Scholes, S; Uzal, F A

    2013-09-01

    A 6-month-old dairy heifer calf with no premonitory signs was acutely down after the morning feeding and could not rise. On presentation, the heifer was in right lateral recumbency and moribund with opisthotonus and left hind limb paddling. Following euthanasia, gross examination of the brain revealed multifocal loss of gray-white matter distinction and extensive petechiae throughout the brainstem. On histopathological examination, there was striking white matter edema and marked perivascular proteinaceous edema surrounding many arterioles and venules (microangiopathy), mainly in the white matter of the internal capsule, thalamus, midbrain, cerebellum, and cerebellar peduncles. The perivascular neuropil was strongly positive for Alzheimer precursor protein A4. Clostridium perfringens epsilon toxin was detected in the intestinal contents. This is the first report of microangiopathy in postneonatal cattle associated with the detection of epsilon toxin in the intestinal contents. PMID:23381925

  10. Detection of preformed type A botulinal toxin in hash brown potatoes by using the mouse bioasssay and a modified ELISA test.

    PubMed

    Ferreira, J L; Eliasberg, S J; Harrison, M A; Edmonds, P

    2001-01-01

    A foodborne illness caused by type A toxin-producing Clostridium botulinum was investigated by using the standard mouse bioassay and a rapid invitro test for toxin detection. The patient, who consumed improperly stored hash brown potatoes that contained the preformed toxin, was diagnosed with type A botulism. C. botulinum type A toxin was detected in the hash brown potatoes as well as in the tryptone-peptone-glucose-yeast extract (TPGY) medium subcultures of this food using the mouse bioassay and an amplified ELISA technique. The mouse bioassay revealed preformed toxin at 10,000 minimum lethal dose (MLD)/g uncooked product and the amplified ELISA an equivalent 50,000 MLD/g. The cultural toxin from the uncooked product killed mice at the 10(6) dilution and a modification of the ELISA procedure was positive at the 10(3) dilution. Cooked food obtained from the consumer's waste can contained 100 MLD/g and the ELISA was also positive at the same dilution of the product. The culture of the cooked product obtained from the waste can was lethal for mice at the 10(7) dilution and positive using the modified ELISA at the 10(4) dilution. The unmodified amplified ELISA method indicated a toxin level of approximately 1 ng/mL (equivalent to 5 x 10(5) MLD/mL) in diluted culture fluid from the uncooked food and the culture of cooked food obtained from the waste can. The hash brown potatoes were negative for types B, E, and F preformed and cultural botulinal toxins using both assays. PMID:11601465

  11. Focal hyperhidrosis secondary to eccrine naevus successfully treated with botulinum toxin type A.

    PubMed

    Lera, M; España, A; Idoate, M Á

    2015-08-01

    Eccrine naevus (EN) is a rare skin hamartoma included in the organoid group of epidermal naevi, histologically defined as focal hyperplasia and/or hypertrophy of eccrine glands. Clinically, EN usually presents as hyperhidrotic patches with no visible skin changes, frequently located on the forearms. The decision to treat EN or not usually depends on the grade of hyperhidrosis, but there is no therapeutic consensus because of the rarity of this condition. We present a case diagnosed as EN in an adult patient with severe localized hyperhidrosis, which was successfully treated with botulinum toxin. PMID:25816711

  12. Biochemical and electrophysiological characterization of two sea anemone type 1 potassium toxins from a geographically distant population of Bunodosoma caissarum.

    PubMed

    Orts, Diego J B; Peigneur, Steve; Madio, Bruno; Cassoli, Juliana S; Montandon, Gabriela G; Pimenta, Adriano M C; Bicudo, José E P W; Freitas, José C; Zaharenko, André J; Tytgat, Jan

    2013-03-01

    Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1-KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. PMID:23466933

  13. Biochemical and Electrophysiological Characterization of Two Sea Anemone Type 1 Potassium Toxins from a Geographically Distant Population of Bunodosoma caissarum

    PubMed Central

    Orts, Diego J. B.; Peigneur, Steve; Madio, Bruno; Cassoli, Juliana S.; Montandon, Gabriela G.; Pimenta, Adriano M. C.; Bicudo, José E. P. W.; Freitas, José C.; Zaharenko, André J.; Tytgat, Jan

    2013-01-01

    Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1–KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. PMID:23466933

  14. Spatial, Temporal, and Matrix Variability of Clostridium botulinum Type E Toxin Gene Distribution at Great Lakes Beaches

    PubMed Central

    Oster, Ryan J.; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen C.

    2015-01-01

    Clostridium botulinum type E toxin is responsible for extensive mortality of birds and fish in the Great Lakes. The C. botulinum bontE gene that produces the type E toxin was amplified with quantitative PCR from 150 sloughed algal samples (primarily Cladophora species) collected during summer 2012 from 10 Great Lakes beaches in five states; concurrently, 74 sediment and 37 water samples from four sites were also analyzed. The bontE gene concentration in algae was significantly higher than in water and sediment (P < 0.05), suggesting that algal mats provide a better microenvironment for C. botulinum. The bontE gene was detected most frequently in algae at Jeorse Park and Portage Lake Front beaches (Lake Michigan) and Bay City State Recreation Area beach on Saginaw Bay (Lake Huron), where 77, 100, and 83% of these algal samples contained the bontE gene, respectively. The highest concentration of bontE was detected at Bay City (1.98 × 105 gene copies/ml of algae or 5.21 × 106 g [dry weight]). This study revealed that the bontE gene is abundant in the Great Lakes but that it has spatial, temporal, and matrix variability. Further, embayed beaches, low wave height, low wind velocity, and greater average water temperature enhance the bontE occurrence. PMID:25888178

  15. Comparative Adjuvant Effects of Type II Heat-Labile Enterotoxins in Combination with Two Different Candidate Ricin Toxin Vaccine Antigens

    PubMed Central

    Vance, David J.; Greene, Christopher J.; Rong, Yinghui; Mandell, Lorrie M.; Connell, Terry D.

    2015-01-01

    Type II heat-labile enterotoxins (HLTs) constitute a promising set of adjuvants that have been shown to enhance humoral and cellular immune responses when coadministered with an array of different proteins, including several pathogen-associated antigens. However, the adjuvant activities of the four best-studied HLTs, LT-IIa, LT-IIb, LT-IIbT13I, and LT-IIc, have never been compared side by side. We therefore conducted immunization studies in which LT-IIa, LT-IIb, LT-IIbT13I, and LT-IIc were coadministered by the intradermal route to mice with two clinically relevant protein subunit vaccine antigens derived from the enzymatic A subunit (RTA) of ricin toxin, RiVax and RVEc. The HLTs were tested with low and high doses of antigen and were assessed for their abilities to stimulate antigen-specific serum IgG titers, ricin toxin-neutralizing activity (TNA), and protective immunity. We found that all four HLTs tested were effective adjuvants when coadministered with RiVax or RVEc. LT-IIa was of particular interest because as little as 0.03 μg when coadministered with RiVax or RVEc proved effective at augmenting ricin toxin-specific serum antibody titers with nominal evidence of local inflammation. Collectively, these results justify the need for further studies into the mechanism(s) underlying LT-IIa adjuvant activity, with the long-term goal of evaluating LT-IIa's activity in humans. PMID:26491037

  16. Sialidases Affect the Host Cell Adherence and Epsilon Toxin-Induced Cytotoxicity of Clostridium perfringens Type D Strain CN3718

    PubMed Central

    Li, Jihong; Sayeed, Sameera; Robertson, Susan; Chen, Jianming; McClane, Bruce A.

    2011-01-01

    Clostridium perfringens type B or D isolates, which cause enterotoxemias or enteritis in livestock, produce epsilon toxin (ETX). ETX is exceptionally potent, earning it a listing as a CDC class B select toxin. Most C. perfringens strains also express up to three different sialidases, although the possible contributions of those enzymes to type B or D pathogenesis remain unclear. Type D isolate CN3718 was found to carry two genes (nanI and nanJ) encoding secreted sialidases and one gene (nanH) encoding a cytoplasmic sialidase. Construction in CN3718 of single nanI, nanJ and nanH null mutants, as well as a nanI/nanJ double null mutant and a triple sialidase null mutant, identified NanI as the major secreted sialidase of this strain. Pretreating MDCK cells with NanI sialidase, or with culture supernatants of BMC206 (an isogenic CN3718 etx null mutant that still produces sialidases) enhanced the subsequent binding and cytotoxic effects of purified ETX. Complementation of BMC207 (an etx/nanH/nanI/nanJ null mutant) showed this effect is mainly attributable to NanI production. Contact between BMC206 and certain mammalian cells (e.g., enterocyte-like Caco-2 cells) resulted in more rapid sialidase production and this effect involved increased transcription of BMC206 nanI gene. BMC206 was shown to adhere to some (e.g. Caco-2 cells), but not all mammalian cells, and this effect was dependent upon sialidase, particularly NanI, expression. Finally, the sialidase activity of NanI (but not NanJ or NanH) could be enhanced by trypsin. Collectively these in vitro findings suggest that, during type D disease originating in the intestines, trypsin may activate NanI, which (in turn) could contribute to intestinal colonization by C. perfringens type D isolates and also increase ETX action. PMID:22174687

  17. Preformed bacterial toxins.

    PubMed

    Crane, J K

    1999-09-01

    Food poisoning syndromes caused by four different bacteria are described. For all types, food kept at a permissive temperature allows growth of the vegetative forms of the bacteria and production of a toxin or toxins. The key features of these syndromes, as well as possible new trends of concern, are summarized in Table 1. PMID:10549427

  18. Exfoliated black phosphorus gas sensing properties at room temperature

    NASA Astrophysics Data System (ADS)

    Donarelli, M.; Ottaviano, L.; Giancaterini, L.; Fioravanti, G.; Perrozzi, F.; Cantalini, C.

    2016-06-01

    Room temperature gas sensing properties of chemically exfoliated black phosphorus (BP) to oxidizing (NO2, CO2) and reducing (NH3, H2, CO) gases in a dry air carrier have been reported. To study the gas sensing properties of BP, chemically exfoliated BP flakes have been drop casted on Si3N4 substrates provided with Pt comb-type interdigitated electrodes in N2 atmosphere. Scanning electron microscopy and x-ray photoelectron spectroscopy characterizations show respectively the occurrence of a mixed structure, composed of BP coarse aggregates dispersed on BP exfoliated few layer flakes bridging the electrodes, and a clear 2p doublet belonging to BP, which excludes the occurrence of surface oxidation. Room temperature electrical tests in dry air show a p-type response of multilayer BP with measured detection limits of 20 ppb and 10 ppm to NO2 and NH3 respectively. No response to CO and CO2 has been detected, while a slight but steady sensitivity to H2 has been recorded. The reported results confirm, on an experimental basis, what was previously theoretically predicted, demonstrating the promising sensing properties of exfoliated BP.

  19. Interaction of three-finger toxins with phospholipid membranes: comparison of S- and P-type cytotoxins

    PubMed Central

    2004-01-01

    The CTs (cytotoxins) I and II are positively charged three-finger folded proteins from venom of Naja oxiana (the Central Asian cobra). They belong to S- and P-type respectively based on Ser-28 and Pro-30 residues within a putative phospholipid bilayer binding site. Previously, we investigated the interaction of CTII with multilamellar liposomes of dipalmitoylphosphatidylglycerol by wide-line 31P-NMR spectroscopy. To compare interactions of these proteins with phospholipids, we investigated the interaction of CTI with the multilamellar liposomes of dipalmitoylphosphatidylglycerol analogously. The effect of CTI on the chemical shielding anisotropy and deformation of the liposomes in the magnetic field was determined at different temperatures and lipid/protein ratios. It was found that both the proteins do not affect lipid organization in the gel state. In the liquid crystalline state of the bilayer they disturb lipid packing. To get insight into the interactions of the toxins with membranes, Monte Carlo simulations of CTI and CTII in the presence of the bilayer membrane were performed. It was found that both the toxins penetrate into the bilayer with the tips of all the three loops. However, the free-energy gain on membrane insertion of CTI is smaller (by ≈7 kcal/mol; 1 kcal≡4.184 kJ) when compared with CTII, because of the lower hydrophobicity of the membrane-binding site of CTI. These results clearly demonstrate that the P-type cytotoxins interact with membranes stronger than those of the S-type, although the mode of the membrane insertion is similar for both the types. PMID:15584897

  20. Influence of pH and temperature on the growth of and toxin production by neurotoxigenic strains of Clostridium butyricum type E.

    PubMed

    Anniballi, Fabrizio; Fenicia, Lucia; Franciosa, Giovanna; Aureli, Paolo

    2002-08-01

    Strains of Clostridium butyricum that produce botulinal toxin type E have been implicated in outbreaks of foodborne botulism in China, India, and Italy, yet the conditions that are favorable for the growth and toxinogenesis of these strains remain to be established. We attempted to determine the temperatures and pH levels that are most conducive to the growth of and toxin production by the six strains of neurotoxigenic C. butyricum that have been implicated in outbreaks of infective and foodborne botulism in Italy. The strains were cultured for 180 days on Trypticase-peptone-glucose-yeast extract broth at various pHs (4.6, 4.8, 5.0, 5.2, 5.4, 5.6, and 5.8) at 30 degrees C and at various temperatures (10, 12, and 15 degrees C) at pH 7.0. Growth was determined by checking for turbidity; toxin production was determined by the mouse bioassay. We also inoculated two foods: mascarpone cheese incubated at 25 and 15 degrees C and pesto sauce incubated at 25 degrees C. The lowest pH at which growth and toxin production occurred was 4.8 at 43 and 44 days of incubation, respectively. The lowest temperature at which growth and toxin production occurred was 12 degrees C, with growth and toxin production first being observed after 15 days. For both foods, toxin production was observed after 5 days at 25 degrees C. Since the strains did not show particularly psychrotrophic behavior, 4 degrees C can be considered a sufficiently low temperature for the inhibition of growth. However, the observation of toxin production in foods at room temperature and at abused refrigeration temperatures demands that these strains be considered a new risk for the food industry. PMID:12182478

  1. Granite Exfoliation, Cosumnes River Watershed, Somerset, California

    NASA Astrophysics Data System (ADS)

    Crockett, I. Q.; Neiss-Cortez, M.

    2015-12-01

    In the Sierra Nevada foothills of California there are many exposed granite plutons within the greater Sierra Nevada batholith. As with most exposed parts of the batholith, these granite slabs exfoliate. It is important to understand exfoliation for issues of public safety as it can cause rock slides near homes, roads, and recreation areas. Through observation, measuring, and mapping we characterize exfoliation in our Cosumnes River watershed community.

  2. Botulinum Toxin Type a as a Therapeutic Agent against Headache and Related Disorders.

    PubMed

    Luvisetto, Siro; Gazerani, Parisa; Cianchetti, Carlo; Pavone, Flaminia

    2015-09-01

    Botulinum neurotoxin A (BoNT/A) is a toxin produced by the naturally-occurring Clostridium botulinum that causes botulism. The potential of BoNT/A as a useful medical intervention was discovered by scientists developing a vaccine to protect against botulism. They found that, when injected into a muscle, BoNT/A causes a flaccid paralysis. Following this discovery, BoNT/A has been used for many years in the treatment of conditions of pathological muscle hyperactivity, like dystonias and spasticities. In parallel, the toxin has become a "glamour" drug due to its power to ward off facial wrinkles, particularly frontal, due to the activity of the mimic muscles. After the discovery that the drug also appeared to have a preventive effect on headache, scientists spent many efforts to study the potentially-therapeutic action of BoNT/A against pain. BoNT/A is effective at reducing pain in a number of disease states, including cervical dystonia, neuropathic pain, lower back pain, spasticity, myofascial pain and bladder pain. In 2010, regulatory approval for the treatment of chronic migraine with BoNT/A was given, notwithstanding the fact that the mechanism of action is still not completely elucidated. In the present review, we summarize experimental evidence that may help to clarify the mechanisms of action of BoNT/A in relation to the alleviation of headache pain, with particular emphasis on preclinical studies, both in animals and humans. Moreover, we summarize the latest clinical trials that show evidence on headache conditions that may obtain benefits from therapy with BoNT/A. PMID:26404377

  3. Botulinum Toxin Type A as a Therapeutic Agent against Headache and Related Disorders

    PubMed Central

    Luvisetto, Siro; Gazerani, Parisa; Cianchetti, Carlo; Pavone, Flaminia

    2015-01-01

    Botulinum neurotoxin A (BoNT/A) is a toxin produced by the naturally-occurring Clostridium botulinum that causes botulism. The potential of BoNT/A as a useful medical intervention was discovered by scientists developing a vaccine to protect against botulism. They found that, when injected into a muscle, BoNT/A causes a flaccid paralysis. Following this discovery, BoNT/A has been used for many years in the treatment of conditions of pathological muscle hyperactivity, like dystonias and spasticities. In parallel, the toxin has become a “glamour” drug due to its power to ward off facial wrinkles, particularly frontal, due to the activity of the mimic muscles. After the discovery that the drug also appeared to have a preventive effect on headache, scientists spent many efforts to study the potentially-therapeutic action of BoNT/A against pain. BoNT/A is effective at reducing pain in a number of disease states, including cervical dystonia, neuropathic pain, lower back pain, spasticity, myofascial pain and bladder pain. In 2010, regulatory approval for the treatment of chronic migraine with BoNT/A was given, notwithstanding the fact that the mechanism of action is still not completely elucidated. In the present review, we summarize experimental evidence that may help to clarify the mechanisms of action of BoNT/A in relation to the alleviation of headache pain, with particular emphasis on preclinical studies, both in animals and humans. Moreover, we summarize the latest clinical trials that show evidence on headache conditions that may obtain benefits from therapy with BoNT/A. PMID:26404377

  4. Effect of Fill Temperature on Clostridium botulinum Type A Toxin Activity during the Hot Filling of Juice Bottles.

    PubMed

    Skinner, Guy E; Fleischman, Gregory J; Balster, Fran; Reineke, Karl; Reddy, N Rukma; Larkin, John W

    2015-08-01

    The potential threat of terrorist attacks against the United States food supply using neurotoxin produced by Clostridium botulinum (BoNT) has resulted in the need for studying the effect of various food process operations on the bioavailability of this toxin. The objective of this study was to evaluate C. botulinum type A neurotoxin bioavailability after a simulated hot fill juice bottling operation. C. botulinum type A acid mud toxin (∼10(6) mouse lethal dose [MLD50]/ml) was deposited into juice bottles at an experimentally determined fastest cooling spot. Bottles (12 or 20 oz [355 and 592 ml]) were filled with either apple juice or an orange drink, at 80 or 85°C, in either upright or inverted orientations. Toxicity of the juice was evaluated as a function of holding time (1 to 2 min) by the mouse bioassay. The fastest cooling point in the upright orientation was determined to be at a bottle's bottom rim. In the inverted orientation, the fastest cooling point was in the bottle cap region. With respect to these two points, the upright bottle cooled faster than the inverted bottle, which was reflected in a higher inactivation of BoNT in the latter. For the orange drink (pH 2.9) toxicity was reduced by 0.5 × 10(6) MLD50/ml to a nondetectable level after 1 min in all bottle sizes, orientations, and temperatures as measured by the mouse bioassay. This indicates that there was at least a 0.5 × 10(6) MLD50/ml reduction in activity. Inactivation in apple juice (pH 4.0), to the same degree as in the orange drink, was found only for the inverted orientation at 85°C. Complete inactivation in apple juice for all conditions was found at a lower added toxin level of 0.25 × 10(5) MLD50/ml. In general, bottle inversion and filling at 85°C provided complete inactivation of BoNT to the 0.5 × 10(6) MLD50/ml level. All experiments resulted in the inactivation of 2.5 × 10(4) MLD50/ml of BoNT regardless of juice type, fill temperature, or bottle orientation and size. PMID

  5. [Characterization of a Cl. Perfringens type D strain, isolated in the field and optimization of epsilon toxin biosynthesis in a cell culture].

    PubMed

    Maaroufi, A; Metoui, W; Rahmouni, S; Ghram, A

    2000-01-01

    A field strain of cl. perfringens, named Dt001, was isolated from kidney of ovine enterotoemia case. The isolate characterized as Cl. perfringens, type D was based on its cultural and biochemical characters and its factors of virulence. The strain was very toxinogenic and well adapted to culture conditions of biofermentation when the parameters related to ptt, incubation time, substrat ... were optimized. Thus, the use of carbon source as polymer (destrine), the continuous control of pH allowed improvement of the rate of biosynthesis of Epsilon toxine by 10 times. The study of the immunogenicity of the isolate showed that preparations of anacultures were more immunogenic then those of anatoxine type. The fact that the two forms of epsilon antigens (protoxin and active toxin) show similar immune response in rabbits, indicates that the proteolytic action of trypsin is limited only to the toxic sites and does not affect the immunogenic epsitopes of the toxin. It also suggests a molecular organization of epsilon toxin in which the immunogenic epsitopes and the toxin sites are apart. The biotechnological performances and the immunogenicity and toxinogenical of the Dt001 isolate are in favor of its possible use as a component of an inactivated vaccine against enterotoxenia. PMID:14658231

  6. An in vivo analysis of facial muscle change treated with botulinum toxin type A using digital image speckle correlation

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Palmaccio, Samantha Palmaccio; Bui, Duc; Dagum, Alexander; Rafailovich, Miriam

    Been famous for clinical use from early 1980s, the neuromuscular blocking agent Botulinum toxin type A (BTX-A), has been used to reduce wrinkles for a long time. Only little research has been done to quantify the change of muscle contraction before and after injection and most research paper depend on subjective evaluation from both patients and surgeons. In our research, Digital Image Speckle Correlation (DISC) was employed to study the mechanical properties of skin, contraction mode of muscles (injected) and reaction of neighbor muscle group (un-injected).At the same time, displacement patterns (vector maps)generated by DISC can predict injection locus for surgeons who normally handle it depending only on visual observation.

  7. Efficacy of reconstituted and stored botulinum toxin type A: an electrophysiologic and visual study in the auricular muscle of the rabbit.

    PubMed

    Jabor, Mark A; Kaushik, Richa; Shayani, Payam; Ruiz-Razura, Amado; Smith, Bruce K; Morimoto, Kaiulani W; Cohen, Benjamin E

    2003-06-01

    Once botulinum toxin type A is reconstituted, the manufacturer recommends that it be used in approximately 4 hours. As a result, a significant amount of this costly drug is often discarded because it is not completely used in the recommended period. The purpose of the present study was to compare fresh versus stored reconstituted botulinum toxin type A for (1) initial potency, (2) duration of action, and (3) bacterial colonization. Using a rabbit model, 20 New Zealand White rabbits were divided into four groups (I to IV). All rabbits had an injection of 2.5 U of reconstituted botulinum toxin into the right anterior auricular muscle. The first group was injected with botulinum toxin type A that was freshly reconstituted and served as the control. The second, third, and fourth groups were injected with botulinum toxin type A that had been reconstituted and stored for 2, 6, and 12 weeks, respectively, in a conventional freezer. Each rabbit had daily visual evaluation of the ear, with the position of auricle being graded from I to III. In addition, each rabbit had a nerve conduction study performed on the right anterior auricular muscle before injection and every 2 weeks after injection. Amplitude was chosen as the principal variable in the data analysis because it is the best predictor of physiologic changes at the muscle motor unit level. The endpoint of the study was defined as the time at which the nerve conduction studies and the visual inspections returned to baseline, preinjection levels. Botulinum toxin type A was also cultured before injection into each group.Overall, the nerve conduction data revealed a trend with a faster recovery (return to baseline) with the stored botulinum toxin. Groups IV and III returned to baseline first, followed by groups II and I. However, there was no significant difference among the groups at 2 and 4 weeks after injection, indicating that initial potency was unchanged. The differences between the groups became significant (p < 0

  8. Confocal microscopy and exfoliative cytology

    PubMed Central

    Reddy, Shyam Prasad; Ramani, Pratibha; Nainani, Purshotam

    2013-01-01

    Context: Early detection of potentially malignant lesions and invasive squamous-cell carcinoma in the oral cavity could be greatly improved through techniques that permit visualization of subtle cellular changes indicative of the neoplastic transformation process. One such technique is confocal microscopy. Combining rapidity with reliability, an innovative idea has been put forward using confocal microscope in exfoliative cytology. Aims: The main objective of this study was to assess confocal microscopy for cytological diagnosis and the results were compared with that of the standard PAP stain. Settings and Design: Confocal microscope, acridine orange (AO) stain, PAP (Papanicolaou) stain. The study was designed to assess confocal microscopy for cytological diagnosis. In the process, smears of patients with (clinically diagnosed and/or suspected) oral squamous cell carcinoma as well as those of controls (normal people) were stained with acridine orange and observed under confocal microscope. The results were compared with those of the standard PAP method. Materials and Methods: Samples of buccal mucosa smears from normal patients and squamous cell carcinoma patients were made, fixed in 100% alcohol, followed by AO staining. The corresponding set of smears was stained with PAP stain using rapid PAP stain kit. The results obtained were compared with those obtained with AO confocal microscopy. Results: The study had shown nuclear changes (malignant cells) in the smears of squamous cell carcinoma patients as increased intensity of fluorescence of the nucleus, when observed under confocal microscope. Acridine orange confocal microscopy showed good amount of sensitivity and specificity (93%) in identifying malignant cells in exfoliative cytological smears. Conclusion: Confocal microscopy was found to have good sensitivity in the identification of cancer (malignant) cells in exfoliative cytology, at par with the PAP method. The rapidity of processing and screening a

  9. Botulinum Toxin Type A Injections for Cervical and Shoulder Girdle Myofascial Pain Using an Enriched Protocol Design

    PubMed Central

    Nicol, Andrea L.; Wu, Irene I.; Ferrante, F. Michael

    2014-01-01

    Background Myofascial pain syndrome is a regional condition of muscle pain and stiffness and is classically characterized by the presence of trigger points in affected musculature. Botulinum toxin type A (BoNT-A) has been shown to have antinociceptive properties and elicit sustained muscle relaxation, thereby possibly affording even greater relief than traditional strategies. Our goal in this study was to determine whether direct injection of BoNT-A into painful muscle groups is effective for cervical and shoulder girdle myofascial pain. Methods An enriched protocol design was used wherein 114 patients with cervical and shoulder girdle myofascial pain underwent injection of BoNT-A to determine their response to the drug. Fifty-four responders were then enrolled in a twelve-week, randomized, double-blind, placebo-controlled trial. Pain scales and quality of life measures were assessed at baseline and at routine follow-up visits until completion of the study after 26 weeks. Results Injection of BoNT-A into painful muscle groups improved average visual numerical pain scores in subjects who received a second dose of BoNT-A compared to placebo (p = 0.019 (0.26, 2.78)). Subjects who received a second dose of BoNT-A had a reduced number of headaches per week (p = 0.04 (0.07, 4.55)). Brief Pain Inventory interference scores for general activity and sleep were improved (p = 0.046 (0.038, 3.7) and 0.02 (0.37, 4.33), respectively) in those who received a second dose of BoNT-A. Conclusion Botulinum toxin type A injected directly into painful muscle groups improves average pain scores and certain aspects of quality of life in patients suffering from severe cervical and shoulder girdle myofascial pain. PMID:24842179

  10. Hydrogen Selective Exfoliated Zeolite Membranes

    SciTech Connect

    Tsapatsis, Michael; Daoutidis, Prodromos; Elyassi, Bahman; Lima, Fernando; Iyer, Aparna; Agrawal, Kumar; Sabnis, Sanket

    2015-04-06

    The objective of this project was to develop and evaluate an innovative membrane technology at process conditions that would be representative of Integrated Gasification Combined Cycle (IGCC) advanced power generation with pre-combustion capture of carbon dioxide (CO2). This research focused on hydrogen (H2)-selective zeolite membranes that could be utilized to separate conditioned syngas into H2-rich and CO2-rich components. Both experiments and process design and optimization calculations were performed to evaluate the concept of ultra-thin membranes made from zeolites nanosheets. In this work, efforts in the laboratory were made to tackle two fundamental challenges in application of zeolite membranes in harsh industrial environments, namely, membrane thickness and membrane stability. Conventional zeolite membranes have thicknesses in the micron range, limiting their performance. In this research, we developed a method for fabrication of ultimately thin zeolite membranes based on zeolite nanosheets. A range of layered zeolites (MWW, RWR, NSI structure types) suitable for hydrogen separation was successfully exfoliated to their constituent nanosheets. Further, membranes were made from one of these zeolites, MWW, to demonstrate the potential of this group of materials. Moreover, long-term steam stability of these zeolites (up to 6 months) was investigated in high concentrations of steam (35 mol% and 95 mole%), high pressure (10 barg), and high temperatures (350 °C and 600 °C) relevant to conditions of water-gas-shift and steam methane reforming reactions. It was found that certain nanosheets are stable, and that stability depends on the concentration of structural defects. Additionally, models that represent a water-gas-shift (WGS) membrane reactor equipped with the zeolite membrane were developed for systems studies. These studies had the aim of analyzing the effect of the membrane reactor integration into IGCC plants

  11. Separation medium containing thermally exfoliated graphite oxide

    NASA Technical Reports Server (NTRS)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Herrera-Alonso, Margarita (Inventor)

    2012-01-01

    A separation medium, such as a chromatography filling or packing, containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g, wherein the thermally exfoliated graphite oxide has a surface that has been at least partially functionalized.

  12. Genome sequencing and comparative genomics provides insights on the evolutionary dynamics and pathogenic potential of different H-Types of Shiga toxin-producing Escherichia coli O104

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various Shiga toxin-producing Escherichia coli (STEC) O104 H-types including H4, H7, H21, and H¯ have been associated with sporadic cases of illness and have caused outbreaks globally. In the U.S., STEC O104:H21 caused an outbreak associated with milk in 1994. The aim of this work was to conduct a...

  13. The Profile of Patients and Current Practice of Treatment of Upper Limb Muscle Spasticity with Botulinum Toxin Type A: An International Survey

    ERIC Educational Resources Information Center

    Bakheit, Abdel Magid

    2010-01-01

    To document the current practice in relation with the treatment of patients with upper limb spasticity with botulinum toxin type A to inform future research in this area. We designed an international, cross-sectional, noninterventional survey of current practice. Nine hundred and seventy-four patients from 122 investigational centres in 31…

  14. Toxins from Bacteria

    PubMed Central

    Henkel, James S.; Baldwin, Michael R.; Barbieri, Joseph T.

    2010-01-01

    Bacterial toxins damage the host at the site of bacterial infection or distanced from the site of infections. Bacterial toxins can be single proteins or organized as oligomeric protein complexes and are organized with distinct AB structure-function properties. The A domain encodes a catalytic activity; ADP-ribosylation of host proteins is the earliest post-translational modification determine to be performed by bacterial toxin, and now include glucosylation and proteolysis among other s. Bacterial toxins also catalyze the non-covalent modification of host protein function or can modify host cell properties through direct protein-protein interactions. The B domain includes two functional domains: a receptor-binding domain, which defines the tropism of a toxin for a cell and a translocation domain that delivers A domain across a lipid bilayer, either on the plasma membrane or the endosome. Bacterial toxins are often characterized based upon the section mechanism that delivers the toxin out of the bacterium, termed type I–VII. This review will overview the major families of bacterial toxins and will also describe the specific structure-function properties of the botulinum neurotoxins. PMID:20358680

  15. Involvement of μ-opioid receptors in antinociceptive action of botulinum toxin type A.

    PubMed

    Drinovac, V; Bach-Rojecky, L; Matak, I; Lacković, Z

    2013-07-01

    Botulinum toxin A (BTX-A) is approved for treatment of chronic migraine and has been investigated in various other painful conditions. Recent evidence demonstrated retrograde axonal transport and suggested the involvement of CNS in antinociceptive effect of BTX-A. However, the mechanism of BTX-A central antinociceptive action is unknown. In this study we investigated the potential role of opioid receptors in BTX-A's antinociceptive activity. In formalin-induced inflammatory pain we assessed the effect of opioid antagonists on antinociceptive activity of BTX-A. Naltrexone was injected subcutaneously (0.02-2 mg/kg) or intrathecally (0.07 μg/10 μl-350 μg/10 μl), while selective μ-antagonist naloxonazine was administered intraperitoneally (5 mg/kg) prior to nociceptive testing. The influence of naltrexone (2 mg/kg s.c.) on BTX-A antinociceptive activity was examined additionally in an experimental neuropathy induced by partial sciatic nerve transection. To investigate the effects of naltrexone and BTX-A on neuronal activation in spinal cord, c-Fos expression was immunohistochemically examined in a model of formalin-induced pain. Antinociceptive effects of BTX-A in formalin and sciatic nerve transection-induced pain were prevented by non-selective opioid antagonist naltrexone. Similarly, BTX-A-induced pain reduction was abolished by low dose of intrathecal naltrexone and by selective μ-antagonist naloxonazine. BTX-A-induced decrease in dorsal horn c-Fos expression was prevented by naltrexone. Prevention of BTX-A effects on pain and c-Fos expression by opioid antagonists suggest that the central antinociceptive action of BTX-A might be associated with the activity of endogenous opioid system (involving μ-opioid receptor). These results provide first insights into the mechanism of BTX-A's central antinociceptive activity. PMID:23499661

  16. Natural killer T (NKT) cells accelerate Shiga toxin type 2 (Stx2) pathology in mice.

    PubMed

    Obata, Fumiko; Subrahmanyam, Priyanka B; Vozenilek, Aimee E; Hippler, Lauren M; Jeffers, Tynae; Tongsuk, Methinee; Tiper, Irina; Saha, Progyaparamita; Jandhyala, Dakshina M; Kolling, Glynis L; Latinovic, Olga; Webb, Tonya J

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemolytic Uremic Syndrome (HUS). The involvement of renal cytokines and chemokines is suspected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO) mice. In CD1KO mice, which lack natural killer T (NKT) cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ, and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease. PMID:25904903

  17. Natural killer T (NKT) cells accelerate Shiga toxin type 2 (Stx2) pathology in mice

    PubMed Central

    Obata, Fumiko; Subrahmanyam, Priyanka B.; Vozenilek, Aimee E.; Hippler, Lauren M.; Jeffers, Tynae; Tongsuk, Methinee; Tiper, Irina; Saha, Progyaparamita; Jandhyala, Dakshina M.; Kolling, Glynis L.; Latinovic, Olga; Webb, Tonya J.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemolytic Uremic Syndrome (HUS). The involvement of renal cytokines and chemokines is suspected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO) mice. In CD1KO mice, which lack natural killer T (NKT) cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ, and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease. PMID:25904903

  18. Botulinum Toxin Type A for the Treatment of Neuropathic Pain in Neuro-Rehabilitation

    PubMed Central

    Intiso, Domenico; Basciani, Mario; Santamato, Andrea; Intiso, Marta; Di Rienzo, Filomena

    2015-01-01

    Pain is a natural protective mechanism and has a warning function signaling imminent or actual tissue damage. Neuropathic pain (NP) results from a dysfunction and derangement in the transmission and signal processing along the nervous system and it is a recognized disease in itself. The prevalence of NP is estimated to be between 6.9% and 10% in the general population. This condition can complicate the recovery from stroke, multiple sclerosis, spinal cord lesions, and several neuropathies promoting persistent disability and poor quality of life. Subjects suffering from NP describe it as burning, itching, lancing, and numbness, but hyperalgesia and allodynia represent the most bothersome symptoms. The management of NP is a clinical challenge and several non-pharmacological and pharmacological interventions have been proposed with variable benefits. Botulinum toxin (BTX) as an adjunct to other interventions can be a useful therapeutic tool for the treatment of disabled people. Although BTX-A is predominantly used to reduce spasticity in a neuro-rehabilitation setting, it has been used in several painful conditions including disorders characterized by NP. The underlying pharmacological mechanisms that operate in reducing pain are still unclear and include blocking nociceptor transduction, the reduction of neurogenic inflammation by inhibiting neural substances and neurotransmitters, and the prevention of peripheral and central sensitization. Some neurological disorders requiring rehabilitative intervention can show neuropathic pain resistant to common analgesic treatment. This paper addresses the effect of BTX-A in treating NP that complicates frequent disorders of the central and peripheral nervous system such as spinal cord injury, post-stroke shoulder pain, and painful diabetic neuropathy, which are commonly managed in a rehabilitation setting. Furthermore, BTX-A has an effect in relief pain that may characterize less common neurological disorders including post

  19. Botulinum Toxin Type A for the Treatment of Neuropathic Pain in Neuro-Rehabilitation.

    PubMed

    Intiso, Domenico; Basciani, Mario; Santamato, Andrea; Intiso, Marta; Di Rienzo, Filomena

    2015-07-01

    Pain is a natural protective mechanism and has a warning function signaling imminent or actual tissue damage. Neuropathic pain (NP) results from a dysfunction and derangement in the transmission and signal processing along the nervous system and it is a recognized disease in itself. The prevalence of NP is estimated to be between 6.9% and 10% in the general population. This condition can complicate the recovery from stroke, multiple sclerosis, spinal cord lesions, and several neuropathies promoting persistent disability and poor quality of life. Subjects suffering from NP describe it as burning, itching, lancing, and numbness, but hyperalgesia and allodynia represent the most bothersome symptoms. The management of NP is a clinical challenge and several non-pharmacological and pharmacological interventions have been proposed with variable benefits. Botulinum toxin (BTX) as an adjunct to other interventions can be a useful therapeutic tool for the treatment of disabled people. Although BTX-A is predominantly used to reduce spasticity in a neuro-rehabilitation setting, it has been used in several painful conditions including disorders characterized by NP. The underlying pharmacological mechanisms that operate in reducing pain are still unclear and include blocking nociceptor transduction, the reduction of neurogenic inflammation by inhibiting neural substances and neurotransmitters, and the prevention of peripheral and central sensitization. Some neurological disorders requiring rehabilitative intervention can show neuropathic pain resistant to common analgesic treatment. This paper addresses the effect of BTX-A in treating NP that complicates frequent disorders of the central and peripheral nervous system such as spinal cord injury, post-stroke shoulder pain, and painful diabetic neuropathy, which are commonly managed in a rehabilitation setting. Furthermore, BTX-A has an effect in relief pain that may characterize less common neurological disorders including post

  20. Phenotypic H-Antigen Typing by Mass Spectrometry Combined with Genetic Typing of H Antigens, O Antigens, and Toxins by Whole-Genome Sequencing Enhances Identification of Escherichia coli Isolates

    PubMed Central

    Chui, Huixia; Domish, Larissa; Sloan, Angela; Hernandez, Drexler; McCorrister, Stuart; Robinson, Alyssia; Walker, Matthew; Peterson, Lorea A. M.; Majcher, Miles; Ratnam, Sam; Haldane, David J. M.; Bekal, Sadjia; Wylie, John; Chui, Linda; Tyler, Shaun; Xu, Bianli; Reimer, Aleisha; Nadon, Celine; Knox, J. David

    2016-01-01

    Mass spectrometry-based phenotypic H-antigen typing (MS-H) combined with whole-genome-sequencing-based genetic identification of H antigens, O antigens, and toxins (WGS-HOT) was used to type 60 clinical Escherichia coli isolates, 43 of which were previously identified as nonmotile, H type undetermined, or O rough by serotyping or having shown discordant MS-H and serotyping results. Whole-genome sequencing confirmed that MS-H was able to provide more accurate data regarding H antigen expression than serotyping. Further, enhanced and more confident O antigen identification resulted from gene cluster based typing in combination with conventional typing based on the gene pair comprising wzx and wzy and that comprising wzm and wzt. The O antigen was identified in 94.6% of the isolates when the two genetic O typing approaches (gene pair and gene cluster) were used in conjunction, in comparison to 78.6% when the gene pair database was used alone. In addition, 98.2% of the isolates showed the existence of genes for various toxins and/or virulence factors, among which verotoxins (Shiga toxin 1 and/or Shiga toxin 2) were 100% concordant with conventional PCR based testing results. With more applications of mass spectrometry and whole-genome sequencing in clinical microbiology laboratories, this combined phenotypic and genetic typing platform (MS-H plus WGS-HOT) should be ideal for pathogenic E. coli typing. PMID:27307455

  1. Phenotypic H-Antigen Typing by Mass Spectrometry Combined with Genetic Typing of H Antigens, O Antigens, and Toxins by Whole-Genome Sequencing Enhances Identification of Escherichia coli Isolates.

    PubMed

    Cheng, Keding; Chui, Huixia; Domish, Larissa; Sloan, Angela; Hernandez, Drexler; McCorrister, Stuart; Robinson, Alyssia; Walker, Matthew; Peterson, Lorea A M; Majcher, Miles; Ratnam, Sam; Haldane, David J M; Bekal, Sadjia; Wylie, John; Chui, Linda; Tyler, Shaun; Xu, Bianli; Reimer, Aleisha; Nadon, Celine; Knox, J David; Wang, Gehua

    2016-08-01

    Mass spectrometry-based phenotypic H-antigen typing (MS-H) combined with whole-genome-sequencing-based genetic identification of H antigens, O antigens, and toxins (WGS-HOT) was used to type 60 clinical Escherichia coli isolates, 43 of which were previously identified as nonmotile, H type undetermined, or O rough by serotyping or having shown discordant MS-H and serotyping results. Whole-genome sequencing confirmed that MS-H was able to provide more accurate data regarding H antigen expression than serotyping. Further, enhanced and more confident O antigen identification resulted from gene cluster based typing in combination with conventional typing based on the gene pair comprising wzx and wzy and that comprising wzm and wzt The O antigen was identified in 94.6% of the isolates when the two genetic O typing approaches (gene pair and gene cluster) were used in conjunction, in comparison to 78.6% when the gene pair database was used alone. In addition, 98.2% of the isolates showed the existence of genes for various toxins and/or virulence factors, among which verotoxins (Shiga toxin 1 and/or Shiga toxin 2) were 100% concordant with conventional PCR based testing results. With more applications of mass spectrometry and whole-genome sequencing in clinical microbiology laboratories, this combined phenotypic and genetic typing platform (MS-H plus WGS-HOT) should be ideal for pathogenic E. coli typing. PMID:27307455

  2. Lack of association of tcdC type and binary toxin status with disease severity and outcome in toxigenic Clostridium difficile.

    PubMed

    Goldenberg, Simon D; French, Gary L

    2011-05-01

    The production of binary toxin and presence of truncating mutations in the putative toxin repressor gene, tcdC, have been associated with the increased virulence and spread of Clostridium difficile, especially ribotype 027. We analysed the prevalence of binary toxin genes and tcdC mutations in 207 clinical C. difficile isolates collected between 2008-2010. The majority (83%) belonged to one of five tcdC types and 8% were ribotype 027. There was little evidence of epidemic spread but there was a high prevalence of both predicted tcdC truncating mutations (15%) and binary toxin genes (28%), which occurred in both 027 and other ribotypes. We measured risk factors (age and laboratory markers) and patient outcomes (severity of disease, ICU admission, mortality, recurrence and length of stay) for patients infected with C. difficile strains with and without these mutations and genes. There was a significantly higher serum C-reactive protein and total peripheral white cell count in the group with predicted tcdC truncating mutations, but no difference in patient outcome. The group with binary toxin genes had a significantly higher total peripheral white cell count and 30 day all cause mortality. We have demonstrated a high prevalence of both predicted tcdC truncating mutations and binary toxin genes in a variety of C. difficile ribotypes, however neither of these factors by themselves predicted clinical virulence. This and other work show that commonly described deletions and truncating mutations do not by themselves explain the virulence of ribotype 027 and other C. difficile strains and further work is required to explain why some isolates appear to produce more severe disease than others. PMID:21396957

  3. Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry.

    PubMed

    Ryder, Christopher R; Wood, Joshua D; Wells, Spencer A; Yang, Yang; Jariwala, Deep; Marks, Tobin J; Schatz, George C; Hersam, Mark C

    2016-06-01

    Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications. PMID:27219705

  4. Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry

    NASA Astrophysics Data System (ADS)

    Ryder, Christopher R.; Wood, Joshua D.; Wells, Spencer A.; Yang, Yang; Jariwala, Deep; Marks, Tobin J.; Schatz, George C.; Hersam, Mark C.

    2016-06-01

    Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)—a layered two-dimensional semiconductor—exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus–carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.

  5. Enhanced expression of recombinant beta toxin of Clostridium perfringens type B using a commercially available Escherichia coli strain.

    PubMed

    Bakhshi, Fatemah; Pilehchian Langroudi, Reza; Imani, Bahram Golestani

    2016-01-01

    Clostridium perfringens beta toxin is only produced by types B and C and plays an important role in many human and animal diseases, causing fatal conditions that originate in the intestines. We compared the expression of C. perfringens type B vaccine strain recombinant beta toxin gene in the Escherichia coli strains RosettaTM(DE3) and BL21(DE3). The beta toxin gene was extracted from pJETβ and ligated with pET22b(+). pET22β was transformed into E. coli strains BL21(DE3) and RosettaTM(DE3). Recombinant protein was expressed as a soluble protein after isopropyl β-D-1-thiogalactopyranoside (IPTG) induction in strain RosettaTM(DE3) but not in BL21(DE3). Expression was optimised by growing recombinant cells at 37 °C and at an induction of 0.5 mM, 1 mM, 1.5 mM IPTG. Expression was evaluated using sodium dodecyl sulfate Polyacrylamide gel electrophoresis (SDS-PAGE). The recombinant protein was purified via Ni-NTA and was analysed using western blot. We concluded that E. coli strain RosettaTM(DE3) can enhance the expression of C. perfringens recombinant beta toxin. PMID:27543150

  6. Mutational Analysis of the Antitoxin in the Lactococcal Type III Toxin-Antitoxin System AbiQ

    PubMed Central

    Bélanger, Maxime

    2015-01-01

    The lactococcal abortive phage infection mechanism AbiQ recently was classified as a type III toxin-antitoxin system in which the toxic protein (ABIQ) is regulated following cleavage of its repeated noncoding RNA antitoxin (antiQ). In this study, we investigated the role of the antitoxin in antiphage activity. The cleavage of antiQ by ABIQ was characterized using 5′ rapid amplification of cDNA ends PCR and was located in an adenine-rich region of antiQ. We next generated a series of derivatives with point mutations within antiQ or with various numbers of antiQ repetitions. These modifications were analyzed for their effect on the antiphage activity (efficiency of plaquing) and on the endoribonuclease activity (Northern hybridization). We observed that increasing or reducing the number of antiQ repeats significantly decreased the antiphage activity of the system. Several point mutations had a similar effect on the antiphage activity and were associated with changes in the digestion profile of antiQ. Interestingly, a point mutation in the putative pseudoknot structure of antiQ mutants led to an increased AbiQ antiphage activity, thereby offering a novel way to increase the activity of an abortive infection mechanism. PMID:25819963

  7. Effectiveness of botulinum toxin type A treatment of neck pain related to nocturnal bruxism: a case report

    PubMed Central

    Santamato, Andrea; Panza, Francesco; Di Venere, Daniela; Solfrizzi, Vincenzo; Frisardi, Vincenza; Ranieri, Maurizio; Fiore, Pietro

    2010-01-01

    Objective This case report describes a patient with nocturnal bruxism and related neck pain treated with botulinum toxin type A (BTX-A). Clinical Features The patient was a 27-year-old man with nocturnal bruxism and difficulty in active mouth opening and chewing and neck pain at rest. His numeric pain score was 7 of 10. Surface electromyography of the temporalis and masseter muscles showed typical signs of hyperactivity, characterized by compound muscle action potential amplitude alterations. Intervention and Outcome After clinical evaluation, he was treated with BTX-A to reduce masseter and temporalis muscle hyperactivity. After 3 days of treatment with BTX-A, with each masseter muscle injected with a dose of about 40 mouse units with a dilution of 1 mL and with temporal muscle bilaterally injected with 25 mouse units with the same dilution, a decrease in bruxism symptoms was reported. Neck pain also decreased after the first treatment (visual analog scale of 2/10) and then resolved completely. After 4 weeks, electromyography showed the reduction of muscle hyperactivity with a decrease in the amplitude of the motor action potential. The same reduction in signs and symptoms was still present at assessment 3 months posttreatment. Conclusion These findings suggest that BTX-A may be a therapeutic option for the treatment of bruxism and related disorders. PMID:22027036

  8. Structural Basis of Cytotoxicity Mediated by the Type III Secretion Toxin ExoU from Pseudomonas aeruginosa

    PubMed Central

    Gendrin, Claire; Contreras-Martel, Carlos; Bouillot, Stéphanie; Elsen, Sylvie; Lemaire, David; Skoufias, Dimitrios A.; Huber, Philippe; Attree, Ina; Dessen, Andréa

    2012-01-01

    The type III secretion system (T3SS) is a complex macromolecular machinery employed by a number of Gram-negative pathogens to inject effectors directly into the cytoplasm of eukaryotic cells. ExoU from the opportunistic pathogen Pseudomonas aeruginosa is one of the most aggressive toxins injected by a T3SS, leading to rapid cell necrosis. Here we report the crystal structure of ExoU in complex with its chaperone, SpcU. ExoU folds into membrane-binding, bridging, and phospholipase domains. SpcU maintains the N-terminus of ExoU in an unfolded state, required for secretion. The phospholipase domain carries an embedded catalytic site whose position within ExoU does not permit direct interaction with the bilayer, which suggests that ExoU must undergo a conformational rearrangement in order to access lipids within the target membrane. The bridging domain connects catalytic domain and membrane-binding domains, the latter of which displays specificity to PI(4,5)P2. Both transfection experiments and infection of eukaryotic cells with ExoU-secreting bacteria show that ExoU ubiquitination results in its co-localization with endosomal markers. This could reflect an attempt of the infected cell to target ExoU for degradation in order to protect itself from its aggressive cytotoxic action. PMID:22496657

  9. Nanopore Sensing of Botulinum Toxin Type B by Discriminating an Enzymatically Cleaved Peptide from a Synaptic Protein Synaptobrevin 2 Derivative

    PubMed Central

    2015-01-01

    Botulinum neurotoxins (BoNTs) are the most lethal toxin known to human. Biodefense requires early and rapid detection of BoNTs. Traditionally, BoNTs can be detected by looking for signs of botulism in mice that receive an injection of human material, serum or stool. While the living animal assay remains the most sensitive approach, it is costly, slow and associated with legal and ethical constrains. Various biochemical, optical and mechanical methods have been developed for BoNTs detection with improved speed, but with lesser sensitivity. Here, we report a novel nanopore-based BoNT type B (BoNT-B) sensor that monitors the toxin’s enzymatic activity on its substrate, a recombinant synaptic protein synaptobrevin 2 derivative. By analyzing the modulation of the pore current caused by the specific BoNT-B-digested peptide as a marker, the presence of BoNT-B at a subnanomolar concentration was identified within minutes. The nanopore detector would fill the niche for a much needed rapid and highly sensitive detection of neurotoxins, and provide an excellent system to explore biophysical mechanisms for biopolymer transportation. PMID:25511125

  10. A multistress responsive type I toxin-antitoxin system: bsrE/SR5 from the B. subtilis chromosome.

    PubMed

    Müller, Peter; Jahn, Natalie; Ring, Christiane; Maiwald, Caroline; Neubert, Robert; Meißner, Christin; Brantl, Sabine

    2016-05-01

    bsrE/SR5 is a type I TA system from prophage-like element P6 of the B. subtilis chromosome. The 256 nt bsrE RNA encodes a 30 aa toxin. The antitoxin SR5 is a 163 nt antisense RNA. Both genes overlap at their 3' ends. Overexpression of bsrE causes cell lysis on agar plates, which can be neutralized by sr5 overexpression, whereas deletion of the chromosomal sr5 copy has no effect. SR5 is short-lived with a half-life of ≈7 min, whereas bsrE RNA is stable with a half-life of >80 min. The sr5 promoter is 10-fold stronger than the bsrE promoter. SR5 interacts with the 3' UTR of bsrE RNA, thereby promoting its degradation by recruiting RNase III. RNase J1 is the main RNase responsible for SR5 and bsrE RNA degradation, and PnpA processes an SR5 precursor to the mature RNA. Hfq stabilizes SR5, but is not required for its inhibitory function. While bsrE RNA is affected by temperature shock and alkaline stress, the amount of SR5 is significantly influenced by various stresses, among them pH, anoxia and iron limitation. Only the latter one is dependent on sigB. Both RNAs are extremely unstable upon ethanol stress due to rapid degradation by RNase Y. PMID:26940229

  11. Comparing the Effect of Botulinum Toxin Type B Injection at Different Dosages for Patient with Drooling due to Brain Lesion

    PubMed Central

    Park, Hee Dong; Park, Sang Jun; Choi, Yong Min

    2012-01-01

    Objective To investigate Botulinum toxin type B (BNT-B) injection's effect and duration depending on dose for patients with brain lesion. Method Twenty one patients with brain lesion and severe drooling were included and divided into three groups. All patients received conventional dysphagia therapy. Group A patients (n=7) received an injection of 1,500 units and group B patients (n=7) received an injection of 2,500 units of BNT-B in submandibular gland under ultrasound guidance. Group C patients (n=7) received conventional dysphagia therapy. Saliva secretion was assessed quantitatively at baseline and at weeks 1, 2, 4, 8, and 12. The severity and frequency of drooling was assessed using the Drooling Quotient (DQ) by patients and/or caregivers. Results Group A and B reported a distinct improvement of the symptoms within 2 weeks after BNT-B injection. Compared to the baseline, the mean amount of saliva decreased significantly throughout the study. However, there was no meaningful difference between the two groups. The greatest reductions were achieved at 2 weeks and lasted up to 8 weeks after BNT-B injection. Group C did not show any differences. Conclusion Local injection of 1,500 units of BNT-B into salivary glands under ultrasonic guidance proved to be a safe and effective dose for drooling in patient with brain lesion, as did 2,500 units. PMID:23342318

  12. Ultrasound exfoliation of inorganic analogues of graphene

    NASA Astrophysics Data System (ADS)

    Štengl, Václav; Henych, Jiří; Slušná, Michaela; Ecorchard, Petra

    2014-04-01

    High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon nitride (h-BCN), and graphitic carbon nitride (g-C3N4)) in liquids leads to the breakdown of the 3D graphitic structure into a 2D structure; the efficiency of this process is highly dependent upon the physical effects of the ultrasound. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were employed to verify the quality of the exfoliation. Herein, this new method of exfoliation with ultrasound assistance for application to mono- and bilayered materials in hydrophobic and hydrophilic environments is presented.

  13. Ultrasound exfoliation of inorganic analogues of graphene

    PubMed Central

    2014-01-01

    High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon nitride (h-BCN), and graphitic carbon nitride (g-C3N4)) in liquids leads to the breakdown of the 3D graphitic structure into a 2D structure; the efficiency of this process is highly dependent upon the physical effects of the ultrasound. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were employed to verify the quality of the exfoliation. Herein, this new method of exfoliation with ultrasound assistance for application to mono- and bilayered materials in hydrophobic and hydrophilic environments is presented. PMID:24708572

  14. A vapBC-type toxin-antitoxin module of Sinorhizobium meliloti influences symbiotic efficiency and nodule senescence of Medicago sativa.

    PubMed

    Lipuma, Justine; Cinege, Gyöngyi; Bodogai, Monica; Oláh, Boglárka; Kiers, Aurélie; Endre, Gabriella; Dupont, Laurence; Dusha, Ilona

    2014-12-01

    The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti carries a large number of toxin-antitoxin (TA) modules both on the chromosome and megaplasmids. One of them, the vapBC-5 module that belongs to the type II systems was characterized here. It encodes an active toxin vapC-5, and was shown to be controlled negatively by the complex of its own proteins. Different mutants of the vapBC-5 genes exhibited diverse effects on symbiotic efficiency during interaction with the host plant Medicago sativa. The absence of the entire vapBC-5 region had no influence on nodule formation and nitrogen fixation properties. The strain carrying an insertion in the antitoxin gene showed a reduced nitrogen fixation capacity resulting in a lower plant yield. In contrast, when the toxin gene was mutated, the strain developed more efficient symbiosis with the host plant. The nitrogen fixing root nodules had a delayed senescent phenotype and contained elevated level of plant-derived molecules characteristic of later steps of nodule development. The longer bacteroid viability and abundance of active nitrogen fixing zone resulted in increased production of plant material. These data indicate that modification of the toxin/antitoxin production may influence bacteroid metabolism and may have an impact on the adaptation to changing environmental conditions. PMID:25156344

  15. Mass Spectrometry-Based Method of Detecting and Distinguishing Type 1 and Type 2 Shiga-Like Toxins in Human Serum

    PubMed Central

    Silva, Christopher J.; Erickson-Beltran, Melissa L.; Skinner, Craig B.; Patfield, Stephanie A.; He, Xiaohua

    2015-01-01

    Shiga-like toxins (verotoxins) are responsible for the virulence associated with a variety of foodborne bacterial pathogens. Direct detection of toxins requires a specific and sensitive technique. In this study, we describe a mass spectrometry-based method of analyzing the tryptic decapeptides derived from the non-toxic B subunits. A gene encoding a single protein that yields a set of relevant peptides upon digestion with trypsin was designed. The 15N-labeled protein was prepared by growing the expressing bacteria in minimal medium supplemented with 15NH4Cl. Trypsin digestion of the 15N-labeled protein yields a set of 15N-labeled peptides for use as internal standards to identify and quantify Shiga or Shiga-like toxins. We determined that this approach can be used to detect, quantify and distinguish among the known Shiga toxins (Stx) and Shiga-like toxins (Stx1 and Stx2) in the low attomole range (per injection) in complex media, including human serum. Furthermore, Stx1a could be detected and distinguished from the newly identified Stx1e in complex media. As new Shiga-like toxins are identified, this approach can be readily modified to detect them. Since intact toxins are digested with trypsin prior to analysis, the handling of intact Shiga toxins is minimized. The analysis can be accomplished within 5 h. PMID:26633510

  16. Induction of apoptosis by Shiga toxins

    PubMed Central

    Tesh, Vernon L

    2010-01-01

    Shiga toxins comprise a family of structurally and functionally related protein toxins expressed by Shigella dysenteriae serotype 1 and multiple serotypes of Escherichia coli. While the capacity of Shiga toxins to inhibit protein synthesis by catalytic inactivation of eukaryotic ribosomes has been well described, it is also apparent that Shiga toxins trigger apoptosis in many cell types. This review presents evidence that Shiga toxins induce apoptosis of epithelial, endothelial, leukocytic, lymphoid and neuronal cells. Apoptotic signaling pathways activated by the toxins are reviewed with an emphasis on signaling mechanisms that are shared among different cell types. Data suggesting that Shiga toxins induce apoptosis through the endoplasmic reticulum stress response and clinical evidence demonstrating apoptosis in humans infected with Shiga toxin-producing bacteria are briefly discussed. The potential for use of Shiga toxins to induce apoptosis in cancer cells is briefly reviewed. PMID:20210553

  17. Displacement-type quartz crystal microbalance immunosensing platform for ultrasensitive monitoring of small molecular toxins.

    PubMed

    Tang, Dianping; Zhang, Bing; Tang, Juan; Hou, Li; Chen, Guonan

    2013-07-16

    A novel displacement-type quartz crystal microbalance (QCM) immunosensing strategy, based on glucose and its analogue dextran for concanavalin A (ConA) binding sites, was designed for ultrasensitive monitoring of small molecular biotoxins (brevetoxin B, PbTx-2, used as a model) with signal amplification on a graphene-functionalized sensing interface. To construct such a QCM immunosensing platform, phenoxy-functionalized dextran (DexP) was initially assembled onto the surface of graphene-coated QCM probe via the π-stacking interaction, and ConA-labeled monoclonal mouse anti-PbTx-2 capture antibody was then immobilized on the DexP-modified probe by dextran-ConA binding. Gold nanoparticle heavily functionalized with glucoamylase and bovine serum albumin-PbTx-2 (PbTx-2-BSA) conjugate was employed as the trace tag. A competitive-type immunoassay format was adopted for the online monitoring of PbTx-2 between anti-PbTx-2 antibody immobilized on the QCM probe and PbTx-2-BSA labeled on the gold nanoparticle. Accompanying the gold nanoparticle, the carried glucoamylase could hydrolyze amylopectin in glucose. The produced glucose competed with dextran for ConA and displaced the ConA-streptavidin-anti-PbTx-2 complex from the QCM probe, resulting in the frequency change. Under optimal conditions, the frequency of the QCM immunosensor was indirectly proportional to the concentration of target PbTx-2 in the sample and exhibited a dynamic range from 1.0 pg·mL(-1) to 10 ng·mL(-1) with a detection limit (LOD) of 0.6 pg·mL(-1) at the 3Sblank level. Intra- and interassay coefficients of variation were below 7.5% and 9.5%, respectively. In addition, the methodology was evaluated for analysis of PbTx-2 in 15 spiked seafood samples and showed good accordance between results obtained by the displacement-type QCM immunosensor and a commercialized enzyme-linked immunosorbent assay (ELISA) method. PMID:23789727

  18. Pertussis toxin

    SciTech Connect

    Sekura, R.D.; Moss, J.; Vaughan, M.

    1985-01-01

    This book contains 13 selections. Some of the titles are: Genetic and Functional Studies of Pertussis Toxin Substrates; Effect of Pertussis Toxin on the Hormonal Responsiveness of Different Tissues; Extracellular Adenylate Cyclase of Bordetella pertussis; and GTP-Regulatory Proteins are Introcellular Messagers: A Model for Hormone Action.

  19. PREDICTION OF OXIDE SCALE EXFOLIATION IN STEAM TUBES

    SciTech Connect

    Sabau, Adrian S; Wright, Ian G

    2010-01-01

    Numerical simulation results are presented for the prediction of the likelihood of oxide scale exfoliation from superheater tubes. The scenarios considered involved alloys T22, TP347H, and TP347HFG subjected to a simplified operating cycle in a power plant generating supercritical steam. The states of stress and strain of the oxides grown in steam were based solely on modeling the various phenomena experienced by superheater tubes during boiler operation, current understanding of the oxidation behavior of each alloy in steam, and consideration of operating parameters such as heat flux, tube dimensions, and boiler duty cycle. Interpretation of the evolution of strain in these scales, and the approach to conditions where scale failure (hence exfoliation) is expected, makes use of the type of Exfoliation Diagrams that incorporate various cracking and exfoliation criteria appropriate for the system considered. In these diagrams, the strain accumulation with time in an oxide is represented by a strain trajectory derived from the net strain resulting from oxide growth, differences in coefficients of thermal expansion among the components, and relaxation due to creep. It was found that an oxide growing on a tube subjected to routine boiler load cycling conditions attained relatively low values of net strain, indicating that oxide failure would not be expected to occur during normal boiler operation. However, during a boiler shut-down event, strains sufficient to exceed the scale failure criteria were developed after times reasonably in accord with plant experience, with the scales on the ferritic steel failing in tension, and those on the austenitic steels in compression. The results presented illustrate that using this approach to track the state of strain in the oxide scale through all phases of boiler operation, including transitions from full-to-low load and shut-down events, offers the possibility of identifying the phase(s) of boiler operation during which oxide

  20. A cross-sectional structured survey of patients receiving botulinum toxin type A treatment for blepharospasm.

    PubMed

    Fezza, John; Burns, John; Woodward, Julie; Truong, Daniel; Hedges, Thomas; Verma, Amit

    2016-08-15

    To characterize satisfaction with current standard-of-care botulinum neurotoxin type A (BoNT/A) treatment for blepharospasm, we performed a cross-sectional, structured survey in subjects with blepharospasm who had received ≥2 BoNT/A cycles. Subjects were interviewed immediately before re-injection to evaluate treatment satisfaction, time course of treatment effects, preferred injection intervals, Jankovic Rating Scale (JRS), and Blepharospasm Disability Index (BSDI). Subjects' (n=114) last treatment was onabotulinumtoxinA (n=78), incobotulinumtoxinA (n=35), or abobotulinumtoxinA (n=1). The most frequent injection interval was 12weeks (46.5% subjects); 30.7% had an interval >12weeks. The main rationale for interval choice was "to maintain treatment efficacy" (44.7%). However, 36.6% reported that treatment effects usually declined within 8weeks; 69.6% within 10weeks. JRS and BSDI scores indicated re-emergence of symptoms before re-injection, with 70.2% and 73.7% of subjects reporting difficulties to drive and read, respectively. Overall, treatment satisfaction was high, but declined at the end of the cycle. Many subjects (52.3%) would prefer an injection interval of <12weeks; 30.6% of <10weeks. In conclusion, the survey results indicate that blepharospasm symptoms, such as difficulties to drive and read, re-emerge at the end of a BoNT treatment cycle and that flexible, individualized treatment intervals may improve treatment satisfaction and outcomes. PMID:27423565

  1. Botulinum Toxin Type A for Cephalic Cutaneous Allodynia in Chronic Migraine: A Randomized, Double-Blinded, Placebo-Controlled Trial

    PubMed Central

    Hollanda, Luciano; Monteiro, Larissa; Melo, Ailton

    2014-01-01

    Cephalic allodynia (CA) can be observed in 50-70% of patients with chronic migraine (CM). The aim of this trial was to assess the efficacy of botulinum toxin type A (Botx-A) in the treatment of CA associated with CM. In this placebo-controlled trial, patients were randomized either into Botx-A or 0.9% saline injections and efficacy measures were assessed every 4 weeks for 3 months. Efficacy endpoints were number of migraine episodes associated with CA, changes from baseline in visual analogical scale scores for pain (VAS) and frequency of common analgesics use for migraine. A total of 38 subjects were randomized to saline (n=18) or Botx-A (n=20). There were no significant differences in baseline between active intervention or placebo groups regarding mean age, number of headache episodes [mean 12.1 (9.22) and 17.00 (9.69) respectively; P=0.12], pain severity as measured by the VAS or frequency of analgesic use for headache episodes. Efficacy analysis showed that Botx-A injections led to an important decrease from baseline in the mean migraine episodes associated with CA after 12 weeks (5.20 versus 11.17; P=0.01). Also, VAS scores and frequency of analgesics use for headache were significantly reduced in the Botx-A group. This study suggests that Botx-A injections are superior to saline in the treatment of CA associated with CM, with mild self limited side effects. PMID:25568735

  2. Efficacy and safety of botulinum toxin type A for treatment of Frey’s syndrome: evidence from 22 published articles

    PubMed Central

    Xie, Shang; Wang, Kan; Xu, Tao; Guo, Xue-Sheng; Shan, Xiao-Feng; Cai, Zhi-Gang

    2015-01-01

    Frey’s syndrome (FS) is an unavoidable sequela following the surgery of the parotid gland. Although several treatment methods are available, their efficacy is short term or accompanied by unacceptable complications. In the past two decades, botulinum toxin type A (BTXA) has been widely used to treat FS. Although several systematic reviews have been reported recently, they were conflicting and with obvious deficiencies. Thus, we performed an objectively systematic review to determine whether BTXA is an effective and safe treatment for FS. A literature retrieval covering PubMed, Web of Science, Ovid, Embase and Cochrane library was performed on 16 January, 2015. Proportion meta-analysis and corresponding 95% confidence interval (CI) were performed to evaluate the efficacy and safety of BXTA in treatment of FS. A total of 499 records were retrieved and 22 articles with 23 studies were included after scrutiny by two independent authors. Statistical analyses regarding the effective rate, incidence of complications were used to estimate the efficacy and safety of BTXA. Our results suggested that the effective rate of BTXA for treatment of FS is 98.5% (95% CI = 0.971–0.994) and the incidence of complication is 3.6% (95% CI = 0.017–0.061). In conclusion, our study supports that BTXA produces meaningful benefits on the treatment of patients with FS. However, owing to lack of strong evidence, future studies with well-designed inclusion criteria and multicenter randomized controlled trials are needed to give more credible evidence, if possible. PMID:26310612

  3. The Inhibitory Effect of Botulinum Toxin Type A on Rat Pyloric Smooth Muscle Contractile Response to Substance P In Vitro

    PubMed Central

    Shao, Yu-Feng; Xie, Jun-Fan; Ren, Yin-Xiang; Wang, Can; Kong, Xiang-Pan; Zong, Xiao-Jian; Fan, Lin-Lan; Hou, Yi-Ping

    2015-01-01

    A decrease in pyloric myoelectrical activity and pyloric substance P (SP) content following intrasphincteric injection of botulinum toxin type A (BTX-A) in free move rats have been demonstrated in our previous studies. The aim of the present study was to investigate the inhibitory effect of BTX-A on rat pyloric muscle contractile response to SP in vitro and the distributions of SP and neurokinin 1 receptor (NK1R) immunoreactive (IR) cells and fibers within pylorus. After treatment with atropine, BTX-A (10 U/mL), similar to [D-Arg1, D-Phe5, D-Trp7,9, Leu11]-SP (APTL-SP, 1 μmol/L) which is an NK1R antagonist, decreased electric field stimulation (EFS)-induced contractile tension and frequency, whereas, subsequent administration of APTL-SP did not act on contractility. Incubation with BTX-A at 4 and 10 U/mL for 4 h respectively decreased SP (1 μmol/L)-induced contractions by 26.64% ± 5.12% and 74.92% ± 3.62%. SP-IR fibers and NK1R-IR cells both located within pylorus including mucosa and circular muscle layer. However, fewer SP-fibers were observed in pylorus treated with BTX-A (10 U/mL). In conclusion, BTX-A inhibits SP release from enteric terminals in pylorus and EFS-induced contractile responses when muscarinic cholinergic receptors are blocked by atropine. In addition, BTX-A concentration- and time-dependently directly inhibits SP-induced pyloric smooth muscle contractility. PMID:26501321

  4. Use of botulinum toxin type A for the treatment of radiation therapy-induced myokymia and neuromyotonia in a dog.

    PubMed

    Rogatko, Cleo P; Glass, Eric N; Kent, Marc; Hammond, James J; de Lahunta, Alexander

    2016-03-01

    CASE DESCRIPTION A 5-year-old castrated male Maltese was evaluated for intermittent clinical signs of muscle cramping and abnormal movements of the skin of the right pelvic limb at the site where an infiltrative lipoma had twice been resected. After the second surgery, the surgical field was treated with radiation therapy (RT). The clinical signs developed approximately 14 months after completion of RT. CLINICAL FINDINGS When clinical signs were present, the right biceps femoris and semitendinosus muscles in the area that received RT were firm and had frequently visible contractions, and the skin overlying those muscles had episodic vermiform movements. Electromyography of those muscles revealed abnormal spontaneous activity with characteristics consistent with myokymic discharges and neuromyotonia. Magnetic resonance imaging of the affected leg revealed no evidence of tumor regrowth. The myokymia and neuromyotonia were considered secondary to RT. TREATMENT AND OUTCOME 4 U of Clostridium botulinum toxin type A (BoNT-A) neurotoxin complex was injected into the affected muscles at each of 6 sites twice during a 24-hour period (ie, 48 U of BoNT-A were administered). The clinical signs were completely resolved 10 days after BoNT-A treatment and were controlled by repeated BoNT-A treatment every 3 to 4 months for > 1 year. CLINICAL RELEVANCE To our knowledge, this is the first report of myokymia and neuromyotonia secondary to RT in a dog. For the dog of this report, injection of BoNT-A into the affected muscles was safe, effective, and easy to perform. PMID:26885596

  5. Serotypes, Virulence Genes, and Intimin Types of Shiga Toxin (Verotoxin)-Producing Escherichia coli Isolates from Healthy Sheep in Spain

    PubMed Central

    Blanco, M.; Blanco, J. E.; Mora, A.; Rey, J.; Alonso, J. M.; Hermoso, M.; Hermoso, J.; Alonso, M. P.; Dahbi, G.; González, E. A.; Bernárdez, M. I.; Blanco, J.

    2003-01-01

    Fecal swabs obtained from 1,300 healthy lambs in 93 flocks in Spain in 1997 were examined for Shiga toxin-producing Escherichia coli (STEC). STEC O157:H7 strains were isolated from 5 (0.4%) animals in 4 flocks, and non-O157 STEC strains were isolated from 462 (36%) lambs in 63 flocks. A total of 384 ovine STEC strains were characterized in this study. PCR showed that 213 (55%) strains carried the stx1 gene, 10 (3%) possessed the stx2 gene, and 161 (42%) carried both the stx1 and the stx2 genes. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 106 (28%) and 23 (6%) of the STEC strains, respectively. The STEC strains belonged to 35 O serogroups and 64 O:H serotypes (including 18 new serotypes). However, 72% were of 1 of the following 12 serotypes: O5:H−, O6:H10, O91:H−, O117:H−, O128:H−, O128:H2, O136:H20, O146:H8, O146:H21, O156:H−, O166:H28, and ONT:H21 (where NT is nontypeable). Although the 384 STEC strains belonged to 95 different seropathotypes (associations between serotypes and virulence genes), 49% of strains belonged to only 11. O91:H− stx1 stx2 (54 strains) was the most common seropathotype, followed by O128:H− stx1 stx2 (33 strains) and O6:H10 stx1 (25 strains). Three strains of serotypes O26:H11, O156:H11, and OX177:H11 had intimin type β1; 5 strains of serotype O157:H7 possessed intimin type γ1; and 15 strains of serotypes O49:H−, O52:H12, O156:H− (12 strains), and O156:H25 had the new intimin, intimin type ζ. The majority (82%) of ovine STEC strains belonged to serotypes previously found to be associated with human STEC strains, and 51% belonged to serotypes associated with STEC strains isolated from patients with hemolytic-uremic syndrome. Thus, this study confirms that healthy sheep are a major reservoir of STEC strains pathogenic for humans. PMID:12682113

  6. Diversity of Fusarium head blight populations and trichothecene toxin types reveals regional differences in pathogen composition and temporal dynamics.

    PubMed

    Kelly, Amy C; Clear, Randall M; O'Donnell, Kerry; McCormick, Susan; Turkington, T Kelly; Tekauz, Andy; Gilbert, Jeannie; Kistler, H Corby; Busman, Mark; Ward, Todd J

    2015-09-01

    Analyses of genetic diversity, trichothecene genotype composition, and population structure were conducted using 4086 Fusarium graminearum isolates collected from wheat in eight Canadian provinces over a three year period between 2005 and 2007. The results revealed substantial regional differences in Fusarium head blight pathogen composition and temporal population dynamics. The 3ADON trichothecene type consistently predominated in Maritime provinces (91%) over the sampled years, and increased significantly (P<0.05) between 2005 and 2007 in western Canada, accounting for 66% of the isolates in Manitoba by the end of the sampling period. In contrast, 3ADON frequency was lower (22%, P<0.001) in the eastern Canadian provinces of Ontario and Québec and did not change significantly between 2005 and 2007, resulting in two distinct longitudinal clines in 3ADON frequency across Canada. Overall, genetic structure was correlated with toxin type, as the endemic population (NA1) was dominated by 15ADON isolates (86%), whereas a second population (NA2) consisted largely of 3ADON isolates (88%). However, the percentage of isolates with trichothecene genotypes that were not predictive of their genetic population assignment (recombinant genotypes) increased from 10% in 2005 to 17% in 2007, indicating that trichothecene type became an increasingly unreliable marker of population identity over time. In addition, there were substantial regional differences in the composition of recombinant genotypes. In western and maritime provinces, NA2 isolates with 15ADON genotypes were significantly more common than NA1 isolates with 3ADON genotypes (P<0.001), and the reverse was true in the eastern provinces of Québec and Ontario. Temporal trends in recombinant genotype composition also varied regionally, as the percentage of 15ADON isolates with NA2 genetic backgrounds increased approximately three fold in western and Maritime provinces, while the opposite trends were observed in Québec and

  7. Solution structure of Ptu1, a toxin from the assassin bug Peirates turpis that blocks the voltage-sensitive calcium channel N-type.

    PubMed

    Bernard, C; Corzo, G; Mosbah, A; Nakajima, T; Darbon, H

    2001-10-30

    Ptu1 is a toxin from the assassin bug Peirates turpis which has been demonstrated to bind reversibly the N-type calcium channels and to have lower affinity than the omega-conotoxin MVIIA. We have determined the solution structure of Ptu1 by use of conventional two-dimensional NMR techniques followed by distance-geometry and molecular dynamics. The calculated structure of Ptu1 belongs to the inhibitory cystin knot structural family (ICK) that consists of a compact disulfide-bonded core from which four loops emerge. Analysis of the 25 converged solutions indicates that the molecular structure of Ptu1 contains a 2-stranded antiparallel beta-sheet (residues 24-27 and 31-34) as the only secondary structure. The loop 2 that has been described to be critical for the binding of the toxin on the channel is similar in Ptu1 and MVIIA. In this loop, the critical residue, Tyr13, in MVIIA is retrieved in Ptu1 as Phe13, but the presence of an acidic residue (Asp16) in Ptu1 could disturb the binding of Ptu1 on the channel and could explain the lower affinity of Ptu1 toward the N-type calcium channel compared to the one of MVIIA. Analysis of the electrostatic charge's repartition gives some insights about the importance of the basic residues, which could interact with acidic residues of the channel and then provide a stabilization of the toxin on the channel. PMID:11669615

  8. Evidence that the Agr-like quorum sensing system regulates the toxin production, cytotoxicity and pathogenicity of Clostridium perfringens type C isolate CN3685.

    PubMed

    Vidal, Jorge E; Ma, Menglin; Saputo, Julian; Garcia, Jorge; Uzal, Francisco A; McClane, Bruce A

    2012-01-01

    Clostridium perfringens possesses at least two functional quorum sensing (QS) systems, i.e. an Agr-like system and a LuxS-dependent AI-2 system. Both of those QS systems can reportedly control in vitro toxin production by C. perfringens but their importance for virulence has not been evaluated. Therefore, the current study assessed whether these QS systems might regulate the pathogenicity of CN3685, a C. perfringens type C strain. Since type C isolates cause both haemorrhagic necrotic enteritis and fatal enterotoxemias (where toxins produced in the intestines are absorbed into the circulation to target other internal organs), the ability of isogenic agrB or luxS mutants to cause necrotizing enteritis in rabbit small intestinal loops or enterotoxemic lethality in mice was evaluated. Results obtained strongly suggest that the Agr-like QS system, but not the LuxS-dependent AI-2 QS system, is required for CN3685 to cause haemorrhagic necrotizing enteritis, apparently because the Agr-like system regulates the production of beta toxin, which is essential for causing this pathology. The Agr-like system, but not the LuxS-mediated AI-2 system, was also important for CN3685 to cause fatal enterotoxemia. These results provide the first direct evidence supporting a role for any QS system in clostridial infections. PMID:22150719

  9. Staphylococcus aureus toxins--their functions and genetics.

    PubMed

    Grumann, Dorothee; Nübel, Ulrich; Bröker, Barbara M

    2014-01-01

    The outcome of encounters between Staphylococcus (S.) aureus and its human host ranges from life-threatening infection through allergic reactions to symptom-free colonization. The pan-genome of this bacterial species encodes numerous toxins, known or strongly suspected to cause specific diseases or symptoms. Three toxin families are in the focus of this review, namely (i) pore-forming toxins, (ii) exfoliative toxins and (iii) superantigens. The majority of toxin-encoding genes are located on mobile genetic elements (MGEs), resulting in a pronounced heterogeneity in the endowment with toxin genes of individual S. aureus strains. Recent population genomic analysis have provided a framework for an improved understanding of the temporal and spatial scales of the motility of MGEs and their associated toxin genes. The distribution of toxin genes among clonal lineages within the species S. aureus is not random, and phylogenetic (sub-)lineages within clonal complexes feature characteristic toxin signatures. When studying pathogenesis, this lineage association, which is caused by the clonal nature of S. aureus makes it difficult to discriminate effects of specific toxins from contributions of the genetic background and/or other associated genetic factors. PMID:23541411

  10. Taxonomic identity of type E botulinum toxin-producing Clostridium butyricum strains by sequencing of a short 16S rDNA region.

    PubMed

    Pourshaban, Manoocheher; Franciosa, Giovanna; Fenicia, Lucia; Aureli, Paolo

    2002-08-27

    Several micro-organisms capable of producing botulinum neurotoxin type E, though phenotypically similar to Clostridium butyricum (a normally non-neurotoxigenic organism), have recently been isolated in Italy and China. Some of these micro-organisms had been implicated in food-borne botulism, a serious neuroparalytic disease. The taxonomic identity of the type E botulinum toxin-producing strains is confirmed here, through sequencing of a genus- and species-specific segment of the 16S rRNA gene. Confirmation leads to the conclusion that neurotoxigenic C. butyricum must be regarded as an emergent food-borne pathogen. PMID:12204382

  11. Millipede toxin

    MedlinePlus

    ... toxin are: Hydrochloric acid Hydrogen cyanide Organic acids Phenol Cresols Benzoquinones Hydroquinones (in some millipedes) ... with plenty of soap and water. Do NOT use alcohol to wash the area. Wash eyes with ...

  12. Millipede toxin

    MedlinePlus

    ... release keeps away most predators. Some large millipede species can secrete these toxins as far as 80 ... reactions are mainly seen from contact with tropical species of millipedes. The outlook may be more serious ...

  13. Marine toxins.

    PubMed

    Whittle, K; Gallacher, S

    2000-01-01

    Seafood products are important both nutritionally and economically. Within Europe, some 12 billion Pounds of fishery products are consumed annually and an enormous variety of species are available. Although seafood is rarely implicated in food poisoning, compared to other food sources, it does provide some specific human health hazards unique to this particular resource. Generally, these are toxins from toxic microscopic algae which accumulate through the food-chain. The toxins can cause various neurological and gastrointestinal illnesses and, potentially, consumers are exposed from seafood produced within Europe, from imported products, or from seafood eaten while travelling abroad. The symptoms of illness which may be encountered, the source and mode of action of the toxins, and some emerging problems are described. European legislation aims to ensure the quality and safety of seafood products by prohibiting sale of some toxic species, setting toxin limits, requiring monitoring and controlling imports. PMID:10885118

  14. Fabrication of Boron Nitride Nanosheets by Exfoliation.

    PubMed

    Wang, Zifeng; Tang, Zijie; Xue, Qi; Huang, Yan; Huang, Yang; Zhu, Minshen; Pei, Zengxia; Li, Hongfei; Jiang, Hongbo; Fu, Chenxi; Zhi, Chunyi

    2016-06-01

    Nanomaterials with layered structures, with their intriguing properties, are of great research interest nowadays. As one of the primary two-dimensional nanomaterials, the hexagonal boron nitride nanosheet (BNNS, also called white graphene), which is an analogue of graphene, possesses various attractive properties, such as high intrinsic thermal conductivity, excellent chemical and thermal stability, and electrical insulation properties. After being discovered, it has been one of the most intensively studied two-dimensional non-carbon nanomaterials and has been applied in a wide range of applications. To support the exploration of applications of BNNSs, exfoliation, as one of the most promising approaches to realize large-scale production of BNNSs, has been intensively investigated. In this review, methods to yield BNNSs by exfoliation will be summarized and compared with other potential fabrication methods of BNNSs. In addition, the future prospects of the exfoliation of h-BN will also be discussed. PMID:27062213

  15. Variability of antibiotic susceptibility and toxin production of Staphylococcus aureus strains isolated from skin, soft tissue, and bone related infections

    PubMed Central

    2013-01-01

    Background Staphylococcus aureus is an opportunistic commensal bacterium that mostly colonizes the skin and soft tissues. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. Here, we characterize a group of genes responsible for toxin production and antibiotic resistance of S. aureus strains isolated from skin, soft tissue, and bone related infections. Results A total of 136 S. aureus strains were collected from five different types of infection: furuncles, pyomyositis, abscesses, Buruli ulcers, and osteomyelitis, from hospital admissions and out-patients in Benin. All strains were resistant to benzyl penicillin, while 25% were resistant to methicillin, and all showed sensitivity to vancomycin. Panton-Valentine leukocidin (PVL) was the most commonly produced virulence factor (70%), followed by staphylococcal enterotoxin B (44%). Exfoliative toxin B was produced by 1.3% of the strains, and was only found in isolates from Buruli ulcers. The tsst-1, sec, and seh genes were rarely detected (≤1%). Conclusions This study provides new insight into the prevalence of toxin and antibiotic resistance genes in S. aureus strains responsible for skin, soft tissue, and bone infections. Our results showed that PVL was strongly associated with pyomyositis and osteomyelitis, and that there is a high prevalence of PVL-MRSA skin infections in Benin. PMID:23924370

  16. Stable liquid crystalline phases of colloidally dispersed exfoliated layered niobates.

    PubMed

    Nakato, Teruyuki; Miyamoto, Nobuyoshi; Harada, Akiko

    2004-01-01

    Colloidally dispersed niobium oxide nanosheets obtained by exfoliation of layered niobates HNb(3)O(8) and HTiNbO(5) formed stable liquid crystalline phases; their liquid crystallinity was dependent on the niobate species exfoliated. PMID:14737341

  17. Crystal structure of Cry6Aa: A novel nematicidal ClyA-type α-pore-forming toxin from Bacillus thuringiensis.

    PubMed

    Huang, Jinbo; Guan, Zeyuan; Wan, Liting; Zou, Tingting; Sun, Ming

    2016-09-01

    Crystal (Cry) proteins from Bacillus thuringiensis (Bt) are globally used in agriculture as proteinaceous insecticides. Numerous crystal structures have been determined, and most exhibit conserved three-dimensional architectures. Recently, we have identified a novel nematicidal mechanism by which Cry6Aa triggers cell death through a necrosis-signaling pathway via an interaction with the host protease ASP-1. However, we found little sequence conservation of Cry6Aa in our functional study. Here, we report the 1.90 angstrom (Å) resolution structure of the proteolytic form of Cry6Aa (1-396), determined by X-ray crystallography. The structure of Cry6Aa is highly similar to those of the pathogenic toxin family of ClyA-type α-pore-forming toxins (α-PFTs), which are characterized by a bipartite structure comprising a head domain and a tail domain, thus suggesting that Cry6Aa exhibits a previously undescribed nematicidal mode of action. This structure also provides a framework for the functional study of other nematicidal toxins. PMID:27381865

  18. MANAGING OXIDE SCALE EXFOLIATION IN BOILERS WITH TP347H SUPERHEATER TUBES

    SciTech Connect

    Sabau, Adrian S; Wright, Ian G.; Shingledecker, John P.; Tortorelli, Peter F

    2014-01-01

    A model based on a concept of fraction of exfoliated area as a function of oxide scale strain energy was developed to predict the extent of exfoliation of steam-side scale from boiler tube superheater loops. As compared with the Armitt diagram, which can be used to predict when scale damage and exfoliation would be likely to occur, a fraction of exfoliated area approach provides an estimation of mass of scale released and the fraction of tube likely to be blocked by the exfoliation. This paper show results for the extent of blockage expected in a single bend of a superheater loop was predicted as a function of operating time, bend geometry, and outlet steam temperature under realistic service conditions that include outages. The deposits of exfoliated scale were assumed to be distributed horizontally the tubes bends. Three types of bends were considered: regular bends, short bends, and hairpin bends. The progressive increase in steam and tube temperatures along a single loop of superheater tubing and the ensuing variation of oxide scale thickness are considered. Numerical simulation results for a superheater loop made of TP347H austenitic steel indicated that tube blockage fractions larger than 50% are likely to occur within the first two years of boiler operation (with regularly scheduled outages) for outlet tube temperatures of 540-570oC, which is consistent with practical experience. Higher blockage fractions were predicted for tubes with short bends and hairpin bends than for tubes with regular bends, of length that are larger than five internal tube diameters. Finally, the blockage model presented can be used with some confidence to devise operating schedules for managing the consequences of oxide scale exfoliation based on projections of time to some critical blockage fraction for specific boiler operating conditions.

  19. Long-Term Effects of Botulinum Toxin Complex Type A Injection on Mechano- and Metabo-Sensitive Afferent Fibers Originating from Gastrocnemius Muscle

    PubMed Central

    Caron, Guillaume; Marqueste, Tanguy; Decherchi, Patrick

    2015-01-01

    The aim of the present study was to investigate long term effects of motor denervation by botulinum toxin complex type A (BoNT/A) from Clostridium Botulinum, on the afferent fibers originating from the gastrocnemius muscle of rats. Animals were divided in 2 experimental groups: 1) untreated animals acting as control and 2) treated animals in which the toxin was injected in the left muscle, the latter being itself divided into 3 subgroups according to their locomotor recovery with the help of a test based on footprint measurements of walking rats: i) no recovery (B0), ii) 50% recovery (B50) and iii) full recovery (B100). Then, muscle properties, metabosensitive afferent fiber responses to potassium chloride (KCl) and lactic acid injections and Electrically-Induced Fatigue (EIF), and mechanosensitive responses to tendon vibrations were measured. At the end of the experiment, rats were killed and the toxin injected muscles were weighted. After toxin injection, we observed a complete paralysis associated to a loss of force to muscle stimulation and a significant muscle atrophy, and a return to baseline when the animals recover. The response to fatigue was only decreased in the B0 group. The responses to KCl injections were only altered in the B100 groups while responses to lactic acid were altered in the 3 injected groups. Finally, our results indicated that neurotoxin altered the biphasic pattern of response of the mechanosensitive fiber to tendon vibrations in the B0 and B50 groups. These results indicated that neurotoxin injection induces muscle afferent activity alterations that persist and even worsen when the muscle has recovered his motor activity. PMID:26485650

  20. Susceptibility of Anthonomus grandis (cotton boll weevil) and Spodoptera frugiperda (fall armyworm) to a cry1ia-type toxin from a Brazilian Bacillus thuringiensis strain.

    PubMed

    Grossi-de-Sa, Maria Fatima; Quezado de Magalhaes, Mariana; Silva, Marilia Santos; Silva, Shirley Margareth Buffon; Dias, Simoni Campos; Nakasu, Erich Yukio Tempel; Brunetta, Patricia Sanglard Felipe; Oliveira, Gustavo Ramos; Neto, Osmundo Brilhante de Oliveira; Sampaio de Oliveira, Raquel; Soares, Luis Henrique Barros; Ayub, Marco Antonio Zachia; Siqueira, Herbert Alvaro Abreu; Figueira, Edson L Z

    2007-09-30

    Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 microg/mL and 5 microg/mL, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil. PMID:17927912

  1. Preparation and characterization of solar exfoliated graphene

    SciTech Connect

    M, Sreejesh S, Nagaraja H.; K, Udaya Bhat

    2014-10-15

    Hummer's method was used for the chemical synthesis of graphite oxide from graphite flakes. Simultaneous exfoliation and reduction of graphite oxide to Graphene was achieved through focused solar light irradiation using a convex lens. The morphological characteristics were studied using SEM and TEM. Layered morphology of Graphene was observed through TEM. Raman spectra and FTIR were used for the structural characterization of Graphene. EDAX analysis showed the drop in oxygen content during exfoliation. The method offered a faster, easier and environmental friendly method to produce Graphene for potential applications.

  2. Exfoliative cheilitis: report of a case.

    PubMed

    Mani, Shani Ann; Shareef, Ban Tawfeek

    2007-09-01

    Exfoliative cheilitis, one of a spectrum of diseases that affect the vermilion border of the lips, is uncommon and has no known cause. However, factors such as stress and some psychiatric conditions are associated with the onset of the disease. This condition is disabling because esthetics and normal functions such as eating, speaking and smiling are compromised. The lack of specific treatment makes exfoliative cheilitis a chronic disease that radically affects a person"s life. This report attempts to further investigate the clinical course of the disease and provides detailed illustrations of the cyclical nature of the disease. PMID:17868515

  3. Method for exfoliation of hexagonal boron nitride

    NASA Technical Reports Server (NTRS)

    Lin, Yi (Inventor); Connell, John W. (Inventor)

    2012-01-01

    A new method is disclosed for the exfoliation of hexagonal boron nitride into mono- and few-layered nanosheets (or nanoplatelets, nanomesh, nanoribbons). The method does not necessarily require high temperature or vacuum, but uses commercially available h-BN powders (or those derived from these materials, bulk crystals) and only requires wet chemical processing. The method is facile, cost efficient, and scalable. The resultant exfoliated h-BN is dispersible in an organic solvent or water thus amenable for solution processing for unique microelectronic or composite applications.

  4. Preparation and characterization of solar exfoliated graphene

    NASA Astrophysics Data System (ADS)

    M, Sreejesh; K, Udaya Bhat; S, Nagaraja H.

    2014-10-01

    Hummer's method was used for the chemical synthesis of graphite oxide from graphite flakes. Simultaneous exfoliation and reduction of graphite oxide to Graphene was achieved through focused solar light irradiation using a convex lens. The morphological characteristics were studied using SEM and TEM. Layered morphology of Graphene was observed through TEM. Raman spectra and FTIR were used for the structural characterization of Graphene. EDAX analysis showed the drop in oxygen content during exfoliation. The method offered a faster, easier and environmental friendly method to produce Graphene for potential applications.

  5. BOTULINUM TOXIN

    PubMed Central

    Nigam, P K; Nigam, Anjana

    2010-01-01

    Botulinum toxin, one of the most poisonous biological substances known, is a neurotoxin produced by the bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable exotoxins (A, B, C1, C2, D, E, F and G). All serotypes interfere with neural transmission by blocking the release of acetylcholine, the principal neurotransmitter at the neuromuscular junction, causing muscle paralysis. The weakness induced by injection with botulinum toxin A usually lasts about three months. Botulinum toxins now play a very significant role in the management of a wide variety of medical conditions, especially strabismus and focal dystonias, hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation, hyperhidrosis, and some chronic conditions that respond only partially to medical treatment. The list of possible new indications is rapidly expanding. The cosmetological applications include correction of lines, creases and wrinkling all over the face, chin, neck, and chest to dermatological applications such as hyperhidrosis. Injections with botulinum toxin are generally well tolerated and side effects are few. A precise knowledge and understanding of the functional anatomy of the mimetic muscles is absolutely necessary to correctly use botulinum toxins in clinical practice. PMID:20418969

  6. Botulinum toxin type A injections for the management of muscle tightness following total hip arthroplasty: a case series

    PubMed Central

    Bhave, Anil; Zywiel, Michael G; Ulrich, Slif D; McGrath, Mike S; Seyler, Thorsten M; Marker, David R; Delanois, Ronald E; Mont, Michael A

    2009-01-01

    Background Development of hip adductor, tensor fascia lata, and rectus femoris muscle contractures following total hip arthroplasties are quite common, with some patients failing to improve despite treatment with a variety of non-operative modalities. The purpose of the present study was to describe the use of and patient outcomes of botulinum toxin injections as an adjunctive treatment for muscle tightness following total hip arthroplasty. Methods Ten patients (14 hips) who had hip adductor, abductor, and/or flexor muscle contractures following total arthroplasty and had been refractory to physical therapeutic efforts were treated with injection of botulinum toxin A. Eight limbs received injections into the adductor muscle, 8 limbs received injections into the tensor fascia lata muscle, and 2 limbs received injection into the rectus femoris muscle, followed by intensive physical therapy for 6 weeks. Results At a mean final follow-up of 20 months, all 14 hips had increased range in the affected arc of motion, with a mean improvement of 23 degrees (range, 10 to 45 degrees). Additionally all hips had an improvement in hip scores, with a significant increase in mean score from 74 points (range, 57 to 91 points) prior to injection to a mean of 96 points (range, 93 to 98) at final follow-up. There were no serious treatment-related adverse events. Conclusion Botulinum toxin A injections combined with intensive physical therapy may be considered as a potential treatment modality, especially in difficult cases of muscle tightness that are refractory to standard therapy. PMID:19709429

  7. Tire containing thermally exfoliated graphite oxide

    NASA Technical Reports Server (NTRS)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A tire, tire lining or inner tube, containing a polymer composite, made of at least one rubber and/or at least one elastomer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g.

  8. Mycobacterium tuberculosis Type II Toxin-Antitoxin Systems: Genetic Polymorphisms and Functional Properties and the Possibility of Their Use for Genotyping

    PubMed Central

    Sagaidak, Maria O.; Bogolubova, Nadezhda A.; Smirnova, Tatiana G.; Andreevskaya, Sofya N.; Larionova, Elena E.; Alekseeva, Maria G.; Chernousova, Larisa N.; Danilenko, Valery N.

    2015-01-01

    Various genetic markers such as IS-elements, DR-elements, variable number tandem repeats (VNTR), single nucleotide polymorphisms (SNPs) in housekeeping genes and other groups of genes are being used for genotyping. We propose a different approach. We suggest the type II toxin-antitoxin (TA) systems, which play a significant role in the formation of pathogenicity, tolerance and persistence phenotypes, and thus in the survival of Mycobacterium tuberculosis in the host organism at various developmental stages (colonization, infection of macrophages, etc.), as the marker genes. Most genes of TA systems function together, forming a single network: an antitoxin from one pair may interact with toxins from other pairs and even from other families. In this work a bioinformatics analysis of genes of the type II TA systems from 173 sequenced genomes of M. tuberculosis was performed. A number of genes of type II TA systems were found to carry SNPs that correlate with specific genotypes. We propose a minimally sufficient set of genes of TA systems for separation of M. tuberculosis strains at nine basic genotype and for further division into subtypes. Using this set of genes, we genotyped a collection consisting of 62 clinical isolates of M. tuberculosis. The possibility of using our set of genes for genotyping using PCR is also demonstrated. PMID:26658274

  9. Mycobacterium tuberculosis Type II Toxin-Antitoxin Systems: Genetic Polymorphisms and Functional Properties and the Possibility of Their Use for Genotyping.

    PubMed

    Zaychikova, Marina V; Zakharevich, Natalia V; Sagaidak, Maria O; Bogolubova, Nadezhda A; Smirnova, Tatiana G; Andreevskaya, Sofya N; Larionova, Elena E; Alekseeva, Maria G; Chernousova, Larisa N; Danilenko, Valery N

    2015-01-01

    Various genetic markers such as IS-elements, DR-elements, variable number tandem repeats (VNTR), single nucleotide polymorphisms (SNPs) in housekeeping genes and other groups of genes are being used for genotyping. We propose a different approach. We suggest the type II toxin-antitoxin (TA) systems, which play a significant role in the formation of pathogenicity, tolerance and persistence phenotypes, and thus in the survival of Mycobacterium tuberculosis in the host organism at various developmental stages (colonization, infection of macrophages, etc.), as the marker genes. Most genes of TA systems function together, forming a single network: an antitoxin from one pair may interact with toxins from other pairs and even from other families. In this work a bioinformatics analysis of genes of the type II TA systems from 173 sequenced genomes of M. tuberculosis was performed. A number of genes of type II TA systems were found to carry SNPs that correlate with specific genotypes. We propose a minimally sufficient set of genes of TA systems for separation of M. tuberculosis strains at nine basic genotype and for further division into subtypes. Using this set of genes, we genotyped a collection consisting of 62 clinical isolates of M. tuberculosis. The possibility of using our set of genes for genotyping using PCR is also demonstrated. PMID:26658274

  10. AvrRxo1 Is a Bifunctional Type III Secreted Effector and Toxin-Antitoxin System Component with Homologs in Diverse Environmental Contexts.

    PubMed

    Triplett, Lindsay R; Shidore, Teja; Long, John; Miao, Jiamin; Wu, Shuchi; Han, Qian; Zhou, Changhe; Ishihara, Hiromichi; Li, Jianyong; Zhao, Bingyu; Leach, Jan E

    2016-01-01

    Toxin-antitoxin (TA) systems are ubiquitous bacterial systems that may function in genome maintenance and metabolic stress management, but are also thought to play a role in virulence by helping pathogens survive stress. We previously demonstrated that the Xanthomonas oryzae pv. oryzicola protein AvrRxo1 is a type III-secreted virulence factor that has structural similarities to the zeta family of TA toxins, and is toxic to plants and bacteria in the absence of its predicted chaperone Arc1. In this work, we confirm that AvrRxo1 and its binding partner Arc1 function as a TA system when expressed in Escherichia coli. Sequences of avrRxo1 homologs were culled from published and newly generated phytopathogen genomes, revealing that avrRxo1:arc1 modules are rare or frequently inactivated in some species and highly conserved in others. Cloning and functional analysis of avrRxo1 from Acidovorax avenae, A. citrulli, Burkholderia andropogonis, Xanthomonas translucens, and Xanthomonas euvesicatoria showed that some AvrRxo1 homologs share the bacteriostatic and Rxo1-mediated cell death triggering activities of AvrRxo1 from X. oryzae. Additional distant putative homologs of avrRxo1 and arc1 were identified in genomic or metagenomic sequence of environmental bacteria with no known pathogenic role. One of these distant homologs was cloned from the filamentous soil bacterium Cystobacter fuscus. avrRxo1 from C. fuscus caused watersoaking and triggered Rxo1-dependent cell collapse in Nicotiana benthamiana, but no growth suppression in E. coli was observed. This work confirms that a type III effector can function as a TA system toxin, and illustrates the potential of microbiome data to reveal new environmental origins or reservoirs of pathogen virulence factors. PMID:27391081

  11. AvrRxo1 Is a Bifunctional Type III Secreted Effector and Toxin-Antitoxin System Component with Homologs in Diverse Environmental Contexts

    PubMed Central

    Triplett, Lindsay R.; Shidore, Teja; Long, John; Miao, Jiamin; Wu, Shuchi; Han, Qian; Zhou, Changhe; Ishihara, Hiromichi; Li, Jianyong; Zhao, Bingyu; Leach, Jan E.

    2016-01-01

    Toxin-antitoxin (TA) systems are ubiquitous bacterial systems that may function in genome maintenance and metabolic stress management, but are also thought to play a role in virulence by helping pathogens survive stress. We previously demonstrated that the Xanthomonas oryzae pv. oryzicola protein AvrRxo1 is a type III-secreted virulence factor that has structural similarities to the zeta family of TA toxins, and is toxic to plants and bacteria in the absence of its predicted chaperone Arc1. In this work, we confirm that AvrRxo1 and its binding partner Arc1 function as a TA system when expressed in Escherichia coli. Sequences of avrRxo1 homologs were culled from published and newly generated phytopathogen genomes, revealing that avrRxo1:arc1 modules are rare or frequently inactivated in some species and highly conserved in others. Cloning and functional analysis of avrRxo1 from Acidovorax avenae, A. citrulli, Burkholderia andropogonis, Xanthomonas translucens, and Xanthomonas euvesicatoria showed that some AvrRxo1 homologs share the bacteriostatic and Rxo1-mediated cell death triggering activities of AvrRxo1 from X. oryzae. Additional distant putative homologs of avrRxo1 and arc1 were identified in genomic or metagenomic sequence of environmental bacteria with no known pathogenic role. One of these distant homologs was cloned from the filamentous soil bacterium Cystobacter fuscus. avrRxo1 from C. fuscus caused watersoaking and triggered Rxo1-dependent cell collapse in Nicotiana benthamiana, but no growth suppression in E. coli was observed. This work confirms that a type III effector can function as a TA system toxin, and illustrates the potential of microbiome data to reveal new environmental origins or reservoirs of pathogen virulence factors. PMID:27391081

  12. Mass spectrometry-based method of detecting and distinguishing type 1 and type 2 Shiga-like toxins in human serum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga-like toxins (verotoxins) are a class of AB5 holotoxins that are responsible for the virulence associated with bacterial pathogens such as Shigella dysenteriae, shigatoxigenic and enterohemorrhagic strains of Escherichia coli (STEC and EHEC), and some Enterobacter strains. The actual expression...

  13. The Staphylococcus aureus lineage-specific markers collagen adhesin and toxic shock syndrome toxin 1 distinguish multilocus sequence typing clonal complexes within spa clonal complexes.

    PubMed

    Deurenberg, Ruud H; Rijnders, Michelle I A; Sebastian, Silvie; Welling, Maaike A; Beisser, Patrick S; Stobberingh, Ellen E

    2009-10-01

    Spa typing/based upon repeat pattern (BURP) sometimes cannot differentiate multilocus sequence typing (MLST) clonal complexes (CCs) within spa-CCs. It has been observed previously that virulence factors, such as collagen adhesin (CNA) and toxic shock syndrome toxin 1 (TSST-1), are associated with certain Staphylococcus aureus lineages. Analysis of methicillin-sensitive and methicillin-resistant S. aureus by spa typing/BURP and detection of CNA and TSST-1 observed an association between CNA and MLST CC1, 12, 22, 30, 45, 51, and 239 and between TSST-1 and MLST CC30. In spa-CC 012, associated with MLST CC7, CC15, and CC30, MLST CC30 could be distinguished from MLST CC7 and CC15 with CNA and TSST-1 as lineage-specific markers. Lineage-specific markers can overcome clustering of nonrelated MLST CCs into 1 spa-CC. PMID:19748421

  14. Exfoliative glaucoma: new evidence in the pathogenesis and treatment.

    PubMed

    Miglior, Stefano; Bertuzzi, Francesca

    2015-01-01

    Exfoliation or pseudoexfoliation syndrome (PXF) is an age-related ocular and systemic disease in which abnormal extracellular material is produced and accumulates in many tissues. PXF is the most common identifiable cause of open-angle glaucoma (OAG). PXFG is a particularly aggressive type of OAG, which runs with a faster rate of progression and poorer response to medical therapy than primary OAG (POAG). The prevalence of the condition shows huge variations among different population, Scandinavian and Mediterranean race being the most affected. Many genetics and environmental factors are involved in the pathogenesis and remarkable progresses in understanding the involved factors have been achieved in the past years. Population-based studies have identified mutations on the lysil-oxidase-like 1(LOXL1) gene as a risk factor for PXFS. Environmental and behavioral factors such as latitude of residence, caffeine intake, and vitamins deficiency are under investigation for a possible involvement in determining the disease in genetically predisposed individuals. Treatment options are similar to those recommended for POAG. Exfoliation syndrome predisposes to capsular rupture, zonular dehiscence, and vitreous loss during cataract extraction. Laser trabeculoplasty has been demonstrated to show good clinical outcomes in PXF patients. A review of the current literature and scientific evidences on pathogenesis and treatment is presented. PMID:26518081

  15. Raman spectroscopy and oral exfoliative cytology

    NASA Astrophysics Data System (ADS)

    Sahu, Aditi; Shah, Nupur; Mahimkar, Manoj; Garud, Mandavi; Pagare, Sandeep; Nair, Sudhir; Krishna, C. Murali

    2014-03-01

    Early detection of oral cancers can substantially improve disease-free survival rates. Ex vivo and in vivo Raman spectroscopic (RS) studies on oral cancer have demonstrated the applicability of RS in identifying not only malignant and premalignant conditions but also cancer-field-effects: the earliest events in oral carcinogenesis. RS has also been explored for cervical exfoliated cells analysis. Exfoliated cells are associated with several advantages like non-invasive sampling, higher patient compliance, transportation and analysis at a central facility: obviating need for on-site instrumentation. Thus, oral exfoliative cytology coupled with RS may serve as a useful adjunct for oral cancer screening. In this study, exfoliated cells from healthy controls with and without tobacco habits, premalignant lesions (leukoplakia and tobacco-pouch-keratosis) and their contralateral mucosa were collected using a Cytobrush. Cells were harvested by vortexing and centrifugation at 6000 rpm. The cellular yield was ascertained using Neubauer's chamber. Cell pellets were placed on a CaF2 window and Raman spectra were acquired using a Raman microprobe (40X objective) coupled HE-785 Raman spectrometer. Approximately 7 spectra were recorded from each pellet, following which pellet was smeared onto a glass slide, fixed in 95% ethanol and subjected to Pap staining for cytological diagnosis (gold standard). Preliminary PC-LDA followed by leave-one-out cross validation indicate delineation of cells from healthy and all pathological conditions. A tendency of classification was also seen between cells from contralateral, healthy tobacco and site of premalignant lesions. These results will be validated by cytological findings, which will serve as the basis for building standard models of each condition.

  16. Anisotropic Thermal Conductivity of Exfoliated Black Phosphorus.

    PubMed

    Jang, Hyejin; Wood, Joshua D; Ryder, Christopher R; Hersam, Mark C; Cahill, David G

    2015-12-22

    The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermo-reflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction. PMID:26516073

  17. Solar Exposure and Residential Geographic History in Relation to Exfoliation Syndrome in the United States and Israel

    PubMed Central

    Pasquale, Louis R.; Jiwani, Aliya Z.; Zehavi-Dorin, Tzukit; Majd, Arow; Rhee, Douglas J.; Chen, Teresa; Turalba, Angela; Shen, Lucy; Brauner, Stacey; Grosskreutz, Cynthia; Gardiner, Matthew; Chen, Sherleen; Borboli-Gerogiannis, Sheila; Greenstein, Scott H.; Chang, Kenneth; Ritch, Robert; Loomis, Stephanie; Kang, Jae H.; Wiggs, Janey L.; Levkovitch-Verbin, Hani

    2014-01-01

    contribute to exfoliation syndrome. The association with work over snow or water and the lack of association with brimmed hat wear suggests that ocular exposure to light from reflective surfaces may be an important type of exposure in exfoliation syndrome etiology. PMID:25188364

  18. Photostability of thin exfoliated black phosphorus

    NASA Astrophysics Data System (ADS)

    Favron, Alexandre; Francoeur, Sébastien; Leonelli, Richard; Martel, Richard

    2014-03-01

    In its bulk form, black phosphorus has a direct gap of about 0.3 eV. Because of its lamellar structure, similar to that of graphite, black phosphorus can be exfoliated down to a single monolayer. The interesting properties is the possible tuning of the energy gap in the Near-IR using control of the layer thickness, which is of great interesting to develop sensors and other Near-IR optoelectronic devices. Preliminary studies on thin exfoliated layers revealed a fast photo-induced oxidation of black phosphorus, in room condition with an excitation higher than 1.8 eV. Using Raman spectroscopy as a probe of the quality and integrity of exfoliated layers, we present in this talk the results of a dynamical study of the photo-oxidation process at room temperature in a controlled atmosphere with the presence of the oxygen-water redox couple. A photo-induced charge transfer from black phosphorus to the redox couple is found to be responsible of the fast deterioration of the structure. Finally, we present Raman and Photoluminescence results on un-oxidized thin-layers measured at low temperature using different passivation schemes.

  19. Evaluation of efficacy and safety of botulinum toxin type A injection in patients requiring temporary tarsorrhaphy to improve corneal epithelial defects

    PubMed Central

    Kasaee, Abolfazl; Musavi, Mohammad Reza; Tabatabaie, Syed Ziaeddin; Hashemian, Mohammad Nasser; Mohebbi, Shahrzad; Khodabandeh, Alireza; Taher Rajabi, Mohammad

    2010-01-01

    AIM To evaluate the efficacy and safety of botulinum toxin type A (Dysport, (Ipsen Biopharm Ltd, Wrexham, UK)) injection in patients requiring temporary tarsorrhaphy to improve corneal epithelial defects. METHODS Thirty patients were enrolled into the prospective study between March 2007 and September 2009. Doses of 15 and 30U of Dysport were injected into the levator palpebrae superioris muscle through the eyelid. The patients were followed daily until completion of ptosis and then 1-2 weekly until complete resolution of levator function and improvement of corneal condition. RESULTS Ptosis took 2.64±1.85 days to be completed (range 1-9 days) and lasted for 12±2.19 weeks. For patients with seventh nerve palsy, 30U Dysport was appropriate to produce sufficient ptosis whereas in other patients 15U of toxin was sufficient. In 83.3% of patients ptosis was sufficient for complete recovery of corneal epithelium and 16.7% required a second procedure (Amniotic membrane transplantation, conjunctival flap). There was a direct correlation between age and duration of ptosis. In patients with seventh nerve palsy, the amount of resultant ptosis was significantly lower than that of other patients. The only adverse effects of injection were superior rectus underaction (33.3%) and diplopia (16.7%) which resolved in all patients without any intervention. CONCLUSION Dysport injection is a safe and effective substitute for surgical tasorrhaphy with fewer complications. PMID:22553562

  20. Effects of Shiga toxin type 2 on a bioengineered three-dimensional model of human renal tissue.

    PubMed

    DesRochers, Teresa M; Kimmerling, Erica Palma; Jandhyala, Dakshina M; El-Jouni, Wassim; Zhou, Jing; Thorpe, Cheleste M; Leong, John M; Kaplan, David L

    2015-01-01

    Shiga toxins (Stx) are a family of cytotoxic proteins that can cause hemolytic-uremic syndrome (HUS), a thrombotic microangiopathy, following infections by Shiga toxin-producing Escherichia coli (STEC). Renal failure is a key feature of HUS and a major cause of childhood renal failure worldwide. There are currently no specific therapies for STEC-associated HUS, and the mechanism of Stx-induced renal injury is not well understood primarily due to a lack of fully representative animal models and an inability to monitor disease progression on a molecular or cellular level in humans at early stages. Three-dimensional (3D) tissue models have been shown to be more in vivo-like in their phenotype and physiology than 2D cultures for numerous disease models, including cancer and polycystic kidney disease. It is unknown whether exposure of a 3D renal tissue model to Stx will yield a more in vivo-like response than 2D cell culture. In this study, we characterized Stx2-mediated cytotoxicity in a bioengineered 3D human renal tissue model previously shown to be a predictor of drug-induced nephrotoxicity and compared its response to Stx2 exposure in 2D cell culture. Our results demonstrate that although many mechanistic aspects of cytotoxicity were similar between 3D and 2D, treatment of the 3D tissues with Stx resulted in an elevated secretion of the kidney injury marker 1 (Kim-1) and the cytokine interleukin-8 compared to the 2D cell cultures. This study represents the first application of 3D tissues for the study of Stx-mediated kidney injury. PMID:25312954

  1. Sequential structural and optical evolution of MoS2 by chemical synthesis and exfoliation

    NASA Astrophysics Data System (ADS)

    Kim, Ju Hwan; Kim, Jungkil; Oh, Si Duck; Kim, Sung; Choi, Suk-Ho

    2015-06-01

    Various types of MoS2 structures are successfully obtained by using economical and facile sequential synthesis and exfoliation methods. Spherically-shaped lumps of multilayer (ML) MoS2 are prepared by using a conventional hydrothermal method and were subsequently 1st-exfoliated in hydrazine while being kept in autoclave to be unrolled and separated into five-to-six-layer MoS2 pieces of several-hundred nm in size. The MoS2 MLs are 2nd-exfoliated in sodium naphthalenide under an Ar ambient to finally produce bilayer MoS2 crystals of ~100 nm. The sequential exfoliation processes downsize MoS2 laterally and reduce its number of layers. The three types of MoS2 allotropes exhibit particular optical properties corresponding to their structural differences. These results suggest that two-dimensional MoS2 crystals can be prepared by employing only chemical techniques without starting from high-pressure-synthesized bulk MoS2 crystals.

  2. A novel pore-forming toxin in type A Clostridium perfringens is associated with both fatal canine hemorrhagic gastroenteritis and fatal foal necrotizing enterocolitis.

    PubMed

    Mehdizadeh Gohari, Iman; Parreira, Valeria R; Nowell, Victoria J; Nicholson, Vivian M; Oliphant, Kaitlyn; Prescott, John F

    2015-01-01

    A role for type A Clostridium perfringens in acute hemorrhagic and necrotizing gastroenteritis in dogs and in necrotizing enterocolitis of neonatal foals has long been suspected but incompletely characterized. The supernatants of an isolate made from a dog and from a foal that died from these diseases were both found to be highly cytotoxic for an equine ovarian (EO) cell line. Partial genome sequencing of the canine isolate revealed three novel putative toxin genes encoding proteins related to the pore-forming Leukocidin/Hemolysin Superfamily; these were designated netE, netF, and netG. netE and netF were located on one large conjugative plasmid, and netG was located with a cpe enterotoxin gene on a second large conjugative plasmid. Mutation and complementation showed that only netF was associated with the cytotoxicity. Although netE and netG were not associated with cytotoxicity, immunoblotting with specific antisera showed these proteins to be expressed in vitro. There was a highly significant association between the presence of netF with type A strains isolated from cases of canine acute hemorrhagic gastroenteritis and foal necrotizing enterocolitis. netE and netF were found in all cytotoxic isolates, as was cpe, but netG was less consistently present. Pulsed-field gel electrophoresis showed that netF-positive isolates belonged to a clonal population; some canine and equine netF-positive isolates were genetically indistinguishable. Equine antisera to recombinant Net proteins showed that only antiserum to rNetF had high supernatant cytotoxin neutralizing activity. The identifica-tion of this novel necrotizing toxin is an important advance in understanding the virulence of type A C. perfringens in specific enteric disease of animals. PMID:25853427

  3. A Novel Pore-Forming Toxin in Type A Clostridium perfringens Is Associated with Both Fatal Canine Hemorrhagic Gastroenteritis and Fatal Foal Necrotizing Enterocolitis

    PubMed Central

    Nowell, Victoria J.; Nicholson, Vivian M.; Oliphant, Kaitlyn; Prescott, John F.

    2015-01-01

    A role for type A Clostridium perfringens in acute hemorrhagic and necrotizing gastroenteritis in dogs and in necrotizing enterocolitis of neonatal foals has long been suspected but incompletely characterized. The supernatants of an isolate made from a dog and from a foal that died from these diseases were both found to be highly cytotoxic for an equine ovarian (EO) cell line. Partial genome sequencing of the canine isolate revealed three novel putative toxin genes encoding proteins related to the pore-forming Leukocidin/Hemolysin Superfamily; these were designated netE, netF, and netG. netE and netF were located on one large conjugative plasmid, and netG was located with a cpe enterotoxin gene on a second large conjugative plasmid. Mutation and complementation showed that only netF was associated with the cytotoxicity. Although netE and netG were not associated with cytotoxicity, immunoblotting with specific antisera showed these proteins to be expressed in vitro. There was a highly significant association between the presence of netF with type A strains isolated from cases of canine acute hemorrhagic gastroenteritis and foal necrotizing enterocolitis. netE and netF were found in all cytotoxic isolates, as was cpe, but netG was less consistently present. Pulsed-field gel electrophoresis showed that netF-positive isolates belonged to a clonal population; some canine and equine netF-positive isolates were genetically indistinguishable. Equine antisera to recombinant Net proteins showed that only antiserum to rNetF had high supernatant cytotoxin neutralizing activity. The identifica-tion of this novel necrotizing toxin is an important advance in understanding the virulence of type A C. perfringens in specific enteric disease of animals. PMID:25853427

  4. A new method for the separation of different types of nematocysts from scyphozoa and investigation of proteinaceous toxins utilizing laser catapulting and subsequent mass spectrometry.

    PubMed

    Wiebring, Annika; Helmholz, Heike; Sötje, Ilka; Lassen, Stephan; Prange, Andreas; Tiemann, Henry

    2010-06-01

    Jellyfish have an increasing impact on marine ecology. Cnidocysts bearing stinging cells afford, amongst others, prey capture and defence. Several different types of stinging capsules are found in one species and they are supposed to have specific functions, e.g. paralysing prey or adhering to it. Due to these assumed different roles of the capsules, it is suggested that toxins, which are contained in the capsules, differ in composition. Analysis of distinct types of nematocysts requires an appropriate method for the separation of the different types. Mixtures of types of nematocysts were obtained of two species of jellyfish, Aurelia aurita and Cyanea lamarckii, by maceration of the tissue. These mixtures were treated with a method called laser microdissection and pressure catapulting (LMPC). Optimized maceration methods, which were firstly introduced as a method for this purpose, in conjunction with optimized LMPC parameters lead to sufficient amounts of separated capsules of individual types for subsequent mass-spectrometric analyses. In case of A. aurita, the resulting mass spectra had some constituents in common, whereas in the overall pattern, the two distinct nematocyst types differed. PMID:20336340

  5. Botulinum neurotoxin D-C uses synaptotagmin I and II as receptors, and human synaptotagmin II is not an effective receptor for type B, D-C and G toxins

    PubMed Central

    Peng, Lisheng; Berntsson, Ronnie P.-A; Tepp, William H.; Pitkin, Rose M.; Johnson, Eric A.; Stenmark, Pål; Dong, Min

    2012-01-01

    Summary Botulinum neurotoxins (BoNTs) are classified into seven types (A–G), but multiple subtype and mosaic toxins exist. These subtype and mosaic toxins share a high sequence identity, and presumably the same receptors and substrates with their parental toxins. Here, we report that a mosaic toxin, type D-C (BoNT/D-C), uses different receptors from its parental toxin BoNT/C. BoNT/D-C, but not BoNT/C, binds directly to the luminal domains of synaptic vesicle proteins synaptotagmin (Syt) I and II, and requires expression of SytI/II to enter neurons. The SytII luminal fragment containing the toxin-binding site can block the entry of BoNT/D-C into neurons and reduce its toxicity in vivo in mice. We also found that gangliosides increase binding of BoNT/D-C to SytI/II and enhance the ability of the SytII luminal fragment to block BoNT/D-C entry into neurons. These data establish SytI/II, in conjunction with gangliosides, as the receptors for BoNT/D-C, and indicate that BoNT/D-C is functionally distinct from BoNT/C. We further found that BoNT/D-C recognizes the same binding site on SytI/II where BoNT/B and G also bind, but utilizes a receptor-binding interface that is distinct from BoNT/B and G. Finally, we also report that human and chimpanzee SytII has diminished binding and function as the receptor for BoNT/B, D-C and G owing to a single residue change from rodent SytII within the toxin binding site, potentially reducing the potency of these BoNTs in humans and chimpanzees. PMID:22454523

  6. Gold-Mediated Exfoliation of Ultralarge Optoelectronically-Perfect Monolayers.

    PubMed

    Desai, Sujay B; Madhvapathy, Surabhi R; Amani, Matin; Kiriya, Daisuke; Hettick, Mark; Tosun, Mahmut; Zhou, Yuzhi; Dubey, Madan; Ager, Joel W; Chrzan, Daryl; Javey, Ali

    2016-06-01

    Gold-mediated exfoliation of ultralarge optoelectronically perfect monolayers with lateral dimensions up to ≈500 μm is reported. Electrical, optical, and X-ray photo-electron spectroscopy characterization show that the quality of the gold-exfoliated flakes is similar to that of tape-exfoliated flakes. Large-area flakes allow manufacturing of large-area mono-layer transition metal dichalcogenide electronics. PMID:27007751

  7. Clostridium perfringens Delta Toxin Is Sequence Related to Beta Toxin, NetB, and Staphylococcus Pore-Forming Toxins, but Shows Functional Differences

    PubMed Central

    Manich, Maria; Knapp, Oliver; Gibert, Maryse; Maier, Elke; Jolivet-Reynaud, Colette; Geny, Blandine; Benz, Roland; Popoff, Michel R.

    2008-01-01

    Clostridium perfringens produces numerous toxins, which are responsible for severe diseases in man and animals. Delta toxin is one of the three hemolysins released by a number of C. perfringens type C and possibly type B strains. Delta toxin was characterized to be cytotoxic for cells expressing the ganglioside GM2 in their membrane. Here we report the genetic characterization of Delta toxin and its pore forming activity in lipid bilayers. Delta toxin consists of 318 amino acids, its 28 N-terminal amino acids corresponding to a signal peptide. The secreted Delta toxin (290 amino acids; 32619 Da) is a basic protein (pI 9.1) which shows a significant homology with C. perfringens Beta toxin (43% identity), with C. perfringens NetB (40% identity) and, to a lesser extent, with Staphylococcus aureus alpha toxin and leukotoxins. Recombinant Delta toxin showed a preference for binding to GM2, in contrast to Beta toxin, which did not bind to gangliosides. It is hemolytic for sheep red blood cells and cytotoxic for HeLa cells. In artificial diphytanoyl phosphatidylcholine membranes, Delta and Beta toxin formed channels. Conductance of the channels formed by Delta toxin, with a value of about 100 pS to more than 1 nS in 1 M KCl and a membrane potential of 20 mV, was higher than those formed by Beta toxin and their distribution was broader. The results of zero-current membrane potential measurements and single channel experiments suggest that Delta toxin forms slightly anion-selective channels, whereas the Beta toxin channels showed a preference for cations under the same conditions. C. perfringens Delta toxin shows a significant sequence homolgy with C. perfringens Beta and NetB toxins, as well as with S. aureus alpha hemolysin and leukotoxins, but exhibits different channel properties in lipid bilayers. In contrast to Beta toxin, Delta toxin recognizes GM2 as receptor and forms anion-selective channels. PMID:19018299

  8. Determination of T-2 toxin, HT-2 toxin, and three other type A trichothecenes in layer feed by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS)--comparison of two sample preparation methods.

    PubMed

    Bernhardt, Katrin; Valenta, Hana; Kersten, Susanne; Humpf, Hans-Ulrich; Dänicke, Sven

    2016-05-01

    A sensitive method for the simultaneous determination of T-2 toxin, HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol in layer feed using high-performance liquid chromatography coupled to triple quadrupole mass spectrometry in the positive ionization mode (LC-ESI-MS/MS) is described. Two fast and easy clean-up methods-with BondElut Mycotoxin and MycoSep 227 columns, respectively-were tested. The separation of the toxins was conducted on a Pursuit XRs Ultra 2.8 HPLC column using 0.13 mM ammonium acetate as eluent A and methanol as eluent B. Detection of the mycotoxins was carried out in the multiple reaction monitoring (MRM) mode using ammonium adducts as precursor ions. Quantification of all analytes was performed with d3-T-2 toxin as an internal standard. The clean-up method with MycoSep 227 columns gave slightly better results for layer feed compared to the method using BondElut Mycotoxin columns (MycoSep 227: recovery between 50 and 63%, BondElut Mycotoxin: recovery between 32 and 67%) and was therefore chosen as the final method. The limits of detection ranged between 0.9 and 7.5 ng/g depending on the mycotoxin. The method was developed for the analysis of layer feed used at carry-over experiments with T-2 toxin in laying hens. For carry-over experiments, it is necessary that the method includes not only T-2 toxin but also the potential metabolites in animal tissues HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol which could naturally occur in cereals used as feed stuff as well. PMID:26940912

  9. Neutralizing antibodies to Shiga toxin type 2 (Stx2) reduce colonization of mice by Stx2-expressing Escherichia coli O157:H7.

    PubMed

    Mohawk, Krystle L; Melton-Celsa, Angela R; Robinson, Cory M; O'Brien, Alison D

    2010-07-01

    Previously, we showed that the Shiga toxin type 2 (Stx2)-expressing Escherichia coli O157:H7 strain 86-24 colonized mice better than did its isogenic stx(2) negative mutant. Here, we confirmed that finding by demonstrating that Stx2 given orally to mice increased the levels of the 86-24 stx(2) mutant shed in feces. Then we assessed the impact of Stx2-neutralizing antibodies, administered passively or generated by immunization with an Stx2 toxoid, on E. coli O157:H7 colonization of mice. We found that such antibodies reduced the E. coli O157:H7 burden in infected mice and, as anticipated, also protected them from weight loss and death. PMID:20472033

  10. Epsilon toxin: a fascinating pore-forming toxin.

    PubMed

    Popoff, Michel R

    2011-12-01

    Epsilon toxin (ETX) is produced by strains of Clostridium perfringens classified as type B or type D. ETX belongs to the heptameric β-pore-forming toxins including aerolysin and Clostridium septicum alpha toxin, which are characterized by the formation of a pore through the plasma membrane of eukaryotic cells consisting in a β-barrel of 14 amphipatic β strands. By contrast to aerolysin and C. septicum alpha toxin, ETX is a much more potent toxin and is responsible for enterotoxemia in animals, mainly sheep. ETX induces perivascular edema in various tissues and accumulates in particular in the kidneys and brain, where it causes edema and necrotic lesions. ETX is able to pass through the blood-brain barrier and stimulate the release of glutamate, which accounts for the symptoms of nervous excitation observed in animal enterotoxemia. At the cellular level, ETX causes rapid swelling followed by cell death involving necrosis. The precise mode of action of ETX remains to be determined. ETX is a powerful toxin, however, it also represents a unique tool with which to vehicle drugs into the central nervous system or target glutamatergic neurons. PMID:21535407

  11. Porous calcium niobate nanosheets prepared by an exfoliation-restacking route.

    PubMed

    Hashemzadeh, Fatemeh

    2016-01-01

    The single phase layered perovskite-type niobate KCa2Nb3O10 was obtained by a solid state reaction of the starting materials (K2CO3, CaCO3 and Nb2O5) at 1,200 °C. Then the H(+)-exchanged form (HCa2Nb3O10) was successfully exfoliated into colloidal porous single layers on the intercalating action of tetra(butyl)ammonium ion. The various characterization techniques such as X-ray diffraction (XRD), field-emission scanning electron microscopy, N2 absorption-desorption and diffuse reflectance UV-visible spectrometry gave important information on the unusual structural features of the perovskite-related niobate nanosheets. XRD analysis of the exfoliated nanosheets showed a unique profile with wide peaks that represented individual molecular aspects of the nanosheets. The Brunauer-Emmett-Teller isotherm of the exfoliated coiled nanosheets showed a sharp increase in the surface area by a factor of >30 in comparison to parent layered material, which is due to the exfoliation and restacking process. The nanosheets in this study were also found to act as a semiconductor with a wide band gap that is due to the quantum size effect. PMID:27003079

  12. Intraprostatic injection of botulinum toxin type- A relieves bladder outlet obstruction in human and induces prostate apoptosis in dogs

    PubMed Central

    Chuang, Yao-Chi; Tu, Chieh-Hsien; Huang, Chao-Cheng; Lin, Hsin-Ju; Chiang, Po-Hui; Yoshimura, Naoki; Chancellor, Michael B

    2006-01-01

    Background With the increasing interest with botulinum toxin – A (BTX-A) application in the lower urinary tract, we investigated the BTX-A effects on the canine prostate and also in men with bladder outlet obstruction (BOO) due to benign prostatic hyperplasia (BPH). Methods Transperineal injection into the prostate using transrectal ultrasound (TRUS) was performed throughout the study. Saline with or without 100 U of BTX-A was injected into mongrel dogs prostate. One or 3 months later, the prostate was harvested for morphologic and apoptotic study. In addition, eight BPH patients refractory to α-blockers were treated with ultrasound guided intraprostatic injection of 200 U of BTX-A. Results In the BTX-A treated dogs, atrophy and diffuse apoptosis was observed with H&E stain and TUNEL stain at 1 and 3 months. Clinically, the mean prostate volume, symptom score, and quality of life index were significantly reduced by 18.8%, 73.1%, and 61.5% respectively. Maximal flow rate significantly increased by 72.0%. Conclusion Intraprostatic BTX-A injection induces prostate apotosis in dogs and relieves BOO in humans. It is therefore a promising alternative treatment for refractory BOO due to BPH. PMID:16620393

  13. Genotoxic and histopathological biomarkers for assessing the effects of magnetic exfoliated vermiculite and exfoliated vermiculite in Danio rerio.

    PubMed

    Cáceres-Vélez, Paolin Rocio; Fascineli, Maria Luiza; Grisolia, Cesar Koppe; de Oliveira Lima, Emília Celma; Sousa, Marcelo Henrique; de Morais, Paulo César; Bentes de Azevedo, Ricardo

    2016-05-01

    Magnetic exfoliated vermiculite is a synthetic nanocomposite that quickly and efficiently absorbs organic compounds such as oil from water bodies. It was developed primarily to mitigate pollution, but the possible adverse impacts of its application have not yet been evaluated. In this context, the acute toxicity of magnetic exfoliated vermiculite and exfoliated vermiculite was herein assessed by genotoxic and histopathological biomarkers in zebrafish (Danio rerio). DNA fragmentation was statistically significant for all groups exposed to the magnetic exfoliated vermiculite and for fish exposed to the highest concentration (200mg/L) of exfoliated vermiculite, whereas the micronucleus frequency, nuclear abnormalities and histopathological alterations were not statistically significant for the fish exposed to these materials. In the intestinal lumen, epithelial cells and goblet cells, we found the presence of magnetic exfoliated vermiculite and exfoliated vermiculite, but no alterations or presence of the materials-test in the gills or liver were observed. Our findings suggest that the use of magnetic exfoliated vermiculite and exfoliated vermiculite during standard ecotoxicological assays caused DNA damage in D. rerio, whose alterations may be likely to be repaired, indicating that the magnetic nanoparticles have the ability to promote genotoxic damage, such as DNA fragmentation, but not mutagenic effects. PMID:26878635

  14. Epsilon-Toxin Production by Clostridium perfringens Type D Strain CN3718 Is Dependent upon the agr Operon but Not the VirS/VirR Two-Component Regulatory System

    PubMed Central

    Chen, Jianming; Rood, Julian I.; McClane, Bruce A.

    2011-01-01

    ABSTRACT Clostridium perfringens type B and D strains cause enterotoxemias and enteritis in livestock after proliferating in the intestines and producing epsilon-toxin (ETX), alpha-toxin (CPA), and, usually, perfringolysin O (PFO). Although ETX is one of the most potent bacterial toxins, the regulation of ETX production by type B or D strains remains poorly understood. The present work determined that the type D strain CN3718 upregulates production of ETX upon close contact with enterocyte-like Caco-2 cells. This host cell-induced upregulation of ETX expression was mediated at the transcriptional level. Using an isogenic agrB null mutant and complemented strain, the agr operon was shown to be required when CN3718 produces ETX in broth culture or, via a secreted signal consistent with a quorum-sensing (QS) effect, upregulates ETX production upon contact with host cells. These findings provide the first insights into the regulation of ETX production, as well as additional evidence that the Agr-like QS system functions as a global regulator of C. perfringens toxin production. Since it was proposed previously that the Agr-like QS system regulates C. perfringens gene expression via the VirS/VirR two-component regulatory system, an isogenic virR null mutant of CN3718 was constructed to evaluate the importance of VirS/VirR for CN3718 toxin production. This mutation affected production of CPA and PFO, but not ETX, by CN3718. These results provide the first indication that C. perfringens toxin expression regulation by the Agr-like quorum-sensing system may not always act via the VirS/VirR two-component system. PMID:22167225

  15. Molecular typing of toxic shock syndrome toxin-1- and Enterotoxin A-producing methicillin-sensitive Staphylococcus aureus isolates from an outbreak in a neonatal intensive care unit.

    PubMed

    Layer, Franziska; Sanchini, Andrea; Strommenger, Birgit; Cuny, Christiane; Breier, Ann-Christin; Proquitté, Hans; Bührer, Christoph; Schenkel, Karl; Bätzing-Feigenbaum, Jörg; Greutelaers, Benedikt; Nübel, Ulrich; Gastmeier, Petra; Eckmanns, Tim; Werner, Guido

    2015-10-01

    Outbreaks of Staphylococcus aureus are common in neonatal intensive care units (NICUs). Usually they are documented for methicillin-resistant strains, while reports involving methicillin-susceptible S. aureus (MSSA) strains are rare. In this study we report the epidemiological and molecular investigation of an MSSA outbreak in a NICU among preterm neonates. Infection control measures and interventions were commissioned by the Local Public Health Authority and supported by the Robert Koch Institute. To support epidemiological investigations molecular typing was done by spa-typing and Multilocus sequence typing; the relatedness of collected isolates was further elucidated by DNA SmaI-macrorestriction, microarray analysis and bacterial whole genome sequencing. A total of 213 neonates, 123 healthcare workers and 205 neonate parents were analyzed in the period November 2011 to November 2012. The outbreak strain was characterized as a MSSA spa-type t021, able to produce toxic shock syndrome toxin-1 and Enterotoxin A. We identified seventeen neonates (of which two died from toxic shock syndrome), four healthcare workers and three parents putatively involved in the outbreak. Whole-genome sequencing permitted to exclude unrelated cases from the outbreak and to discuss the role of healthcare workers as a reservoir of S. aureus on the NICU. Genome comparisons also indicated the presence of the respective clone on the ward months before the first colonized/infected neonates were detected. PMID:26321006

  16. Foam stabilisation using surfactant exfoliated graphene.

    PubMed

    Sham, Alison Y W; Notley, Shannon M

    2016-05-01

    Liquid-air foams have been stabilised using a suspension of graphene particles at very low particle loadings. The suspension was prepared through the liquid phase exfoliation of graphite in the presence of the non-ionic tri-block surfactant, Pluronic® F108. The graphene particles possess an extremely high aspect ratio, with lateral dimensions of between 0.1 and 1.3 μm as evidenced by TEM imaging. The particles were shown to exhibit a number of other properties known to favour stabilisation of foam structures. Particle surface activity was confirmed through surface tension measurements, suggesting the particles favour adsorption at the air-water interface. The evolution of bubble size distributions over time indicated the presence of particles yielded improvements to foam stability due to a reduction in disproportionation. Foam stability measurements showed a non-linear relationship between foam half-life and graphene concentration, indicative of the rate at which particles adsorb at bubble surfaces. The wettability of the graphene particles was altered upon addition of alkali metal chlorides, with the stability of the foams being enhanced according to the series Na(+)>Li(+)>K(+)>Cs(+). This effect is indicative of the relative hydration capacity of each salt with respect to the surfactant, which is adsorbed along the graphene plane as a result of the exfoliation process. Thus, surfactant exfoliated graphene particles exhibit a number of different features that demonstrate efficient application of high-aspect ratio particles in the customisation and enhancement of foams. PMID:26890385

  17. Comparative Characterization of Shiga Toxin Type 2 and Subtilase Cytotoxin Effects on Human Renal Epithelial and Endothelial Cells Grown in Monolayer and Bilayer Conditions

    PubMed Central

    Álvarez, Romina S.; Sacerdoti, Flavia; Jancic, Carolina; Paton, Adrienne W.; Paton, James C.; Ibarra, Cristina; Amaral, María M.

    2016-01-01

    Postdiarrheal hemolytic uremic syndrome (HUS) affects children under 5 years old and is responsible for the development of acute and chronic renal failure, particularly in Argentina. This pathology is a complication of Shiga toxin (Stx)-producing Escherichia coli infection and renal damage is attributed to Stx types 1 and 2 (Stx1, Stx2) produced by Escherichia coli O157:H7 and many other STEC serotypes. It has been reported the production of Subtilase cytotoxin (SubAB) by non-O157 STEC isolated from cases of childhood diarrhea. Therefore, it is proposed that SubAB may contribute to HUS pathogenesis. The human kidney is the most affected organ because very Stx-sensitive cells express high amounts of biologically active receptor. In this study, we investigated the effects of Stx2 and SubAB on primary cultures of human glomerular endothelial cells (HGEC) and on a human tubular epithelial cell line (HK-2) in monoculture and coculture conditions. We have established the coculture as a human renal proximal tubule model to study water absorption and cytotoxicity in the presence of Stx2 and SubAB. We obtained and characterized cocultures of HGEC and HK-2. Under basal conditions, HGEC monolayers exhibited the lowest electrical resistance (TEER) and the highest water permeability, while the HGEC/HK-2 bilayers showed the highest TEER and the lowest water permeability. In addition, at times as short as 20–30 minutes, Stx2 and SubAB caused the inhibition of water absorption across HK-2 and HGEC monolayers and this effect was not related to a decrease in cell viability. However, toxins did not have inhibitory effects on water movement across HGEC/HK-2 bilayers. After 72 h, Stx2 inhibited the cell viability of HGEC and HK-2 monolayers, but these effects were attenuated in HGEC/HK-2 bilayers. On the other hand, SubAB cytotoxicity shows a tendency to be attenuated by the bilayers. Our data provide evidence about the different effects of these toxins on the bilayers respect to the

  18. The Effect of Total Cumulative Dose, Number of Treatment Cycles, Interval between Injections, and Length of Treatment on the Frequency of Occurrence of Antibodies to Botulinum Toxin Type A in the Treatment of Muscle Spasticity

    ERIC Educational Resources Information Center

    Bakheit, Abdel Magid O.; Liptrot, Anthea; Newton, Rachel; Pickett, Andrew M.

    2012-01-01

    A large cumulative dose of botulinum toxin type A (BoNT-A), frequent injections, a short interval between treatment cycles, and a long duration of treatment have all been suggested, but not confirmed, to be associated with a high incidence of neutralizing antibodies to the neurotoxin. The aim of this study was to investigate whether these…

  19. Botulinum Toxin Type A Injection for Spastic Equinovarus Foot in Children with Spastic Cerebral Palsy: Effects on Gait and Foot Pressure Distribution

    PubMed Central

    Choi, Ja Young; Jung, Soojin; Rha, Dong-wook

    2016-01-01

    Purpose To investigate the effect of intramuscular Botulinum toxin type A (BoNT-A) injection on gait and dynamic foot pressure distribution in children with spastic cerebral palsy (CP) with dynamic equinovarus foot. Materials and Methods Twenty-five legs of 25 children with CP were investigated in this study. BoNT-A was injected into the gastrocnemius (GCM) and tibialis posterior (TP) muscles under the guidance of ultrasonography. The effects of the toxin were clinically assessed using the modified Ashworth scale (MAS) and modified Tardieu scale (MTS), and a computerized gait analysis and dynamic foot pressure measurements using the F-scan system were also performed before injection and at 1 and 4 months after injection. Results Spasticity of the ankle plantar-flexor in both the MAS and MTS was significantly reduced at both 1 and 4 months after injection. On dynamic foot pressure measurements, the center of pressure index and coronal index, which represent the asymmetrical weight-bearing of the medial and lateral columns of the foot, significantly improved at both 1 and 4 months after injection. The dynamic foot pressure index, total contact area, contact length and hind foot contact width all increased at 1 month after injection, suggesting better heel contact. Ankle kinematic data were significantly improved at both 1 and 4 months after injection, and ankle power generation was significantly increased at 4 months after injection compared to baseline data. Conclusion Using a computerized gait analysis and foot scan, this study revealed significant benefits of BoNT-A injection into the GCM and TP muscles for dynamic equinovarus foot in children with spastic CP. PMID:26847306

  20. Factors influencing response to Botulinum toxin type A in patients with idiopathic cervical dystonia: results from an international observational study

    PubMed Central

    Ehler, Edvard; Zakine, Benjamin; Maisonobe, Pascal; Simonetta-Moreau, Marion

    2012-01-01

    Objectives Real-life data on response to Botulinum toxin A (BoNT-A) in cervical dystonia (CD) are sparse. An expert group of neurologists was convened with the overall aim of developing a definition of treatment response, which could be applied in a non-interventional study of BoNT-A-treated subjects with CD. Design International, multicentre, prospective, observational study of a single injection cycle of BoNT-A as part of normal clinical practice. Setting 38 centres across Australia, Belgium, Czech Republic, France, Germany, The Netherlands, Portugal, Russia and the UK. Participants 404 adult subjects with idiopathic CD. Most subjects were women, aged 41–60 years and had previously received BoNT-A. Outcome measures Patients were classified as responders if they met all the following four criteria: magnitude of effect (≥25% improvement Toronto Western Spasmodic Torticollis Rating Scale), duration of effect (≥12-week interval between the BoNT-A injection day and subject-reported waning of treatment effect), tolerability (absence of severe related adverse event) and subject's positive Clinical Global Improvement (CGI). Results High rates of response were observed for magnitude of effect (73.6%), tolerability (97.5%) and subject's clinical global improvement (69.8%). The subjective duration of effect criterion was achieved by 49.3% of subjects; 28.6% of subjects achieved the responder definition. Factors most strongly associated with response were age (<40 years; OR 3.9, p<0.05) and absence of baseline head tremor (OR 1.5; not significant). Conclusions Three of four criteria were met by most patients. The proposed multidimensional definition of response appears to be practical for routine practice. Unrealistically high patient expectation and subjectivity may influence the perception of a quick waning of effect, but highlights that this aspect may be a hurdle to response in some patients. Clinical registration number (NCT00833196; ClinicalTrials.gov). PMID

  1. A spider toxin, ω-agatoxin IV A, binds to fixed as well as living tissues: cytochemical visualization of P/Q-type calcium channels.

    PubMed

    Nakanishi, Setsuko

    2016-08-01

    ω-Agatoxin IV A, a peptidyl toxin from Agelenopsis aperta venom, selectively binds to voltage-gated P/Q-type calcium channels. ω-Agatoxin IV A has been used as a selective tool in pharmacological and electrophysiological studies. Visualization of P/Q-type calcium channels has previously been accomplished using biotin-conjugated ω-Agatoxin IV A in freshly prepared mouse cerebellar and hippocampal slices (Nakanishi et al, J. Neurosci. Res., 41: , 532, 1995). Here biotinylated ω-agatoxin IV A was applied to transcardially fixed brain slices prepared with various fixatives. ω-Agatoxin IV A did not bind to fixed tissues from P/Q-type calcium channel knockout mice, confirming that binding to normal, fixed tissues was not an artifact. Using transmission electron microscopy, locations of biotinylated ω-agatoxin IV A binding sites visualized with gold-conjugated streptavidin showed a similar pattern to those visualized with antibody. The ability of biotinylated ω-agatoxin IV A to bind to fixed tissue provides a new cytochemical technique to study molecular architecture of synapses. PMID:27095701

  2. Microwave Assisted 2D Materials Exfoliation

    NASA Astrophysics Data System (ADS)

    Wang, Yanbin

    Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.

  3. Exfoliation of montmorillonite in protein solutions.

    PubMed

    Kolman, Krzysztof; Steffen, Werner; Bugla-Płoskońska, Gabriela; Skwara, Aleksandra; Pigłowski, Jacek; Butt, Hans-Jürgen; Kiersnowski, Adam

    2012-05-15

    In the study we demonstrate a method to obtain stable, exfoliated montmorillonite-protein complexes by adsorption of the proteins extracted from hen-egg albumen. Analysis of the process by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the complexes are formed by sequential adsorption of ovotransferrin, ovalbumins, ovomucoid and lysozyme on the surface of the silicate. Structural studies performed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the adsorption of ovotransferrin and albumins is accompanied by disintegration of clay stacks into discrete platelets. Further analysis by dynamic light scattering (DLS) revealed that at protein to silicate weight ratios exceeding 20, the synergistic adsorption of albumen components leads to reaggregation of silicate platelets into disordered, microgel-like particles. By means of DLS it was found that exfoliation predominantly leads to formation of particles with average hydrodynamic radii (R(h)) of 0.19 μm while their aggregation causes formation of particles having R(h) in of approx. 0.5 μm and larger. PMID:22405581

  4. Distribution and inferred age of exfoliation joints in the Aar Granite of the central Swiss Alps and relationship to Quaternary landscape evolution

    NASA Astrophysics Data System (ADS)

    Ziegler, Martin; Loew, Simon; Moore, Jeffrey R.

    2013-11-01

    Exfoliation joints are well-known natural fractures limited to near the ground surface. Relatively few details, however, are known about their distribution and age in the Swiss Alps. Exfoliation joints follow the landscape surface at the time of their formation; the age of the associated landscape feature then provides a maximum age of exfoliation joints. While landscape forms can change through time, exfoliation joints preserve elements of former landscape morphologies by their undisturbed orientations. The Grimsel region of the Central Alps is well-suited for analyzing the impact of erosional episodes, and accompanying stress changes, on exfoliation joint formation in granitic rocks. Mapping above and below ground revealed that exfoliation joints are widespread and occur between valley bottoms and mountain crests within glacial (inner and hanging U-shaped trough valleys, glacial cirques, and steep mountain crests) and predominantly fluvial landforms (gently inclined linear slopes above the inner trough valleys, narrow inner-valley gorges, and steep V-shaped side gullies). Based primarily on their geometric properties at the ground surface, three exfoliation joint types were distinguished in our study area: (1) closely spaced (< 1 m) joints oriented distinctly parallel to the present-day ground surface, (2) intermediately spaced (0.6-2 m) joints that are nearly parallel (< 10° difference) to today's mean ground surface at a 10-m scale, and (3) widely spaced (≫ 2 m) joints not parallel to the ground surface. Relating the mapped distribution of exfoliation joint types to identified erosional episodes and landscape features of known and inferred ages, respectively, enables us to distinguish four exfoliation joint generations in the Grimsel area, which most likely formed during the lower Pleistocene (~ 1.5-1 Ma), middle Pleistocene (~ 0.7-0.4 Ma), upper Pleistocene (0.1-0.02 Ma), and Late Glacial/Holocene (< 0.02 Ma). We demonstrate that the most prominent and

  5. Animal Toxins: How is Complexity Represented in Databases?

    PubMed Central

    Jungo, Florence; Estreicher, Anne; Bairoch, Amos; Bougueleret, Lydie; Xenarios, Ioannis

    2010-01-01

    Peptide toxins synthesized by venomous animals have been extensively studied in the last decades. To be useful to the scientific community, this knowledge has been stored, annotated and made easy to retrieve by several databases. The aim of this article is to present what type of information users can access from each database. ArachnoServer and ConoServer focus on spider toxins and cone snail toxins, respectively. UniProtKB, a generalist protein knowledgebase, has an animal toxin-dedicated annotation program that includes toxins from all venomous animals. Finally, the ATDB metadatabase compiles data and annotations from other databases and provides toxin ontology. PMID:22069583

  6. Animal Toxins: How is Complexity Represented in Databases?

    PubMed

    Jungo, Florence; Estreicher, Anne; Bairoch, Amos; Bougueleret, Lydie; Xenarios, Ioannis

    2010-02-01

    Peptide toxins synthesized by venomous animals have been extensively studied in the last decades. To be useful to the scientific community, this knowledge has been stored, annotated and made easy to retrieve by several databases. The aim of this article is to present what type of information users can access from each database. ArachnoServer and ConoServer focus on spider toxins and cone snail toxins, respectively. UniProtKB, a generalist protein knowledgebase, has an animal toxin-dedicated annotation program that includes toxins from all venomous animals. Finally, the ATDB metadatabase compiles data and annotations from other databases and provides toxin ontology. PMID:22069583

  7. Stability and infectivity of cytolethal distending toxin type V gene-carrying bacteriophages in a water mesocosm and under different inactivation conditions.

    PubMed

    Allué-Guardia, Anna; Jofre, Juan; Muniesa, Maite

    2012-08-01

    Two cytolethal distending toxin (Cdt) type V-encoding bacteriophages (Φ62 and Φ125) were induced spontaneously from their wild-type Escherichia coli strains and from the lysogens generated in Shigella sonnei. The stability of Cdt phages was determined at various temperatures and pH values after 1 month of storage by means of infectivity tests using a plaque blot assay and analysis of phage genomes using real-time quantitative PCR (qPCR): both were highly stable. We assessed the inactivation of Cdt phages by thermal treatment, chlorination, UV radiation, and in a mesocosm in both summer and winter. The results for the two Cdt phages showed similar trends and were also similar to the phage SOM23 used for reference, but they showed a much higher persistence than Cdt-producing E. coli. Cdt phages showed maximal inactivation after 1 h at 70°C, 30 min of UV radiation, and 30 min of contact with a 10-ppm chlorine treatment. Inactivation in a mesocosm was higher in summer than in winter, probably because of solar radiation. The treatments reduced the number of infectious phages but did not have a significant effect on the Cdt phage particles detected by qPCR. Cdt phages were quantified by qPCR in 73% of river samples, and these results suggest that Cdt phages are a genetic vehicle and the natural reservoir for cdt in the environment. PMID:22685154

  8. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis

    PubMed Central

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis. PMID:26807591

  9. Relation between time spent outdoors and exfoliation glaucoma or exfoliation glaucoma suspect

    PubMed Central

    Kang, Jae Hee; Wiggs, Janey L.; Pasquale, Louis R.

    2014-01-01

    Purpose To evaluate the relation between time spent outdoors at various life periods and risk of exfoliation glaucoma or exfoliation glaucoma suspect. Design Retrospective cohort study in the United States. Methods Participants (49,033 women in the Nurses Health Study and 20,066 men in the Health Professionals Follow-up Study) were 60+ years old, free of glaucoma and cataract, reported eye exams and completed questions about time spent outdoors in direct sunlight at mid-day at 3 life periods: high school to age 24 years, age 25-35 years, and age 36-59 years (asked in 2006 in women and 2008 in men). Participants were followed biennially with mailed questionnaires from 1980 (women) / 1986 (men) to 2010. Incident cases (223 women and 38 men) were confirmed with medical records. Cohort-specific multivariable-adjusted rate ratios from Cox proportional hazards models were estimated and pooled with meta-analysis. Results Although no association was observed with greater time spent outdoors in the ages of 25-35 or ages 36-59 years, the pooled multivariable-adjusted rate ratios for ≥11 hours per week spent outdoors in high school to age 24 years compared with ≤5 hours per week was 2.00 (95% confidence interval=1.30, 3.08; p for linear trend=0.001). In women, this association was stronger in those who resided in the southern geographic tier in young adulthood (p for interaction = 0.07). Conclusions Greater time spent outdoors in young adulthood was associated with risk of exfoliation glaucoma or exfoliation glaucoma suspect, supporting an etiologic role of early exposures to climatic factors. PMID:24857689

  10. NVC-422 Inactivates Staphylococcus aureus Toxins

    PubMed Central

    Jekle, Andreas; Yoon, Jungjoo; Zuck, Meghan; Najafi, Ramin; Wang, Lu; Shiau, Timothy; Francavilla, Charles; Rani, Suriani Abdul; Eitzinger, Christian; Nagl, Markus; Anderson, Mark

    2013-01-01

    Bacterial pathogens have specific virulence factors (e.g., toxins) that contribute significantly to the virulence and infectivity of microorganisms within the human hosts. Virulence factors are molecules expressed by pathogens that enable colonization, immunoevasion, and immunosuppression, obtaining nutrients from the host or gaining entry into host cells. They can cause pathogenesis by inhibiting or stimulating certain host functions. For example, in systemic Staphylococcus aureus infections, virulence factors such as toxic shock syndrome toxin 1 (TSST-1), staphylococcal enterotoxin A (SEA), and staphylococcal enterotoxin B (SEB) cause sepsis or toxic shock by uncontrolled stimulation of T lymphocytes and by triggering a cytokine storm. In vitro, these superantigens stimulate the proliferation of human peripheral blood mononuclear cells (PBMC) and the release of many cytokines. NVC-422 (N,N-dichloro-2,2-dimethyltaurine) is a broad-spectrum, fast-acting topical anti-infective agent against microbial pathogens, including antibiotic-resistant microbes. Using mass spectrometry, we demonstrate here that NVC-422 oxidizes methionine residues of TSST-1, SEA, SEB, and exfoliative toxin A (ETA). Exposure of virulence factors to 0.1% NVC-422 for 1 h prevented TSST-1-, SEA-, SEB-, and ETA-induced cell proliferation and cytokine release. Moreover, NVC-422 also delayed and reduced the protein A- and clumping factor-associated agglutination of S. aureus cultures. These results show that, in addition to its well-described direct microbicidal activity, NVC-422 can inactivate S. aureus virulence factors through rapid oxidation of methionines. PMID:23208720

  11. Surfactant mediated liquid phase exfoliation of graphene

    NASA Astrophysics Data System (ADS)

    Narayan, Rekha; Kim, Sang Ouk

    2015-10-01

    Commercialization of graphene based applications inevitably requires cost effective mass production. From the early days of research on graphene, direct liquid phase exfoliation (LPE) of graphite has been considered as the most promising strategy to produce high-quality mono or few-layer graphene sheets in solvent dispersion forms. Substantial success has been achieved thus far in the LPE of graphene employing numerous solvent systems and suitable surfactants. This invited review article principally showcase the recent research progress as well as shortcomings of surfactant assisted LPE of graphene. In particular, a comprehensive assessment of the quality and yield of the graphene sheets produced by different categories of the surfactants are summarized. Future direction of LPE methods is also proposed for the eventual success of commercial applications.

  12. Ferromagnetism in exfoliated tungsten disulfide nanosheets

    PubMed Central

    2013-01-01

    Two-dimensional-layered transition metal dichalcogenides nanosheets have attracted tremendous attention for their promising applications in spintronics because the atomic-thick nanosheets can not only enhance the intrinsic properties of their bulk counterparts, but also give birth to new promising properties. In this paper, ultrathin tungsten disulfide (WS2) nanosheets were gotten by liquid exfoliation route from its bulk form using dimethylformamide (DMF). Compared to the antiferromagnetism bulk WS2, ultrathin WS2 nanosheets show intrinsic room-temperature ferromagnetism (FM) with the maximized saturation magnetization of 0.004 emu/g at 10 K, where the appearance of FM in the nanosheets is partly due to the presence of zigzag edges in the magnetic ground state at the grain boundaries. PMID:24134699

  13. Laboratory Investigation of the First Case of Botulism Caused by Clostridium butyricum Type E Toxin in the United States.

    PubMed

    Dykes, Janet K; Lúquez, Carolina; Raphael, Brian H; McCroskey, Loretta; Maslanka, Susan E

    2015-10-01

    We report here the laboratory investigation of the first known case of botulism in the United States caused by Clostridium butyricum type E. This investigation demonstrates the importance of extensive microbiological examination of specimens, which resulted in the isolation of this organism. PMID:26246485

  14. Evaluation of Nanoclay Exfoliation Strategies for Thermoset Polyimide Nanocomposite Systems

    NASA Technical Reports Server (NTRS)

    Ginter, Michael J.; Jana, Sadhan C.; Miller, Sandi G.

    2007-01-01

    Prior works show exfoliated layered silicate reinforcement improves polymer composite properties. However, achieving full clay exfoliation in high performance thermoset polyimides remains a challenge. This study explores a new method of clay exfoliation, which includes clay intercalation by lower molecular weight PMR monomer under conditions of low and high shear and sonication, clay treatments by aliphatic and aromatic surfactants, and clay dispersion in primary, higher molecular weight PMR resin. Clay spacing, thermal, and mechanical properties were evaluated and compared with the best results available in literature for PMR polyimide systems.

  15. Correction of post-traumatic anterior open bite by injection of botulinum toxin type A into the anterior belly of the digastric muscle: case report

    PubMed Central

    Park, Yong-Tae; Kim, Seong-Gon; Park, Young-Wook

    2013-01-01

    Post-traumatic anterior open bite can occur as a result of broken balance among the masticatory muscles. The superior hyoid muscle group retracts the mandible downward and contributes to the anterior open bite. Denervation of the digastric muscle by injection of botulinum toxin type A (BTX-A) can reduce the power of the digastric muscle and help to resolve the post-traumatic anterior open bite. A patient with a bilateral angle fracture had an anterior open bite even after undergoing three operations under general anesthesia and rubber traction. Although the open bite showed some improvement by the repeated operation, the occlusion was still unstable six weeks after the initial treatment. To eliminate the residual anterior open bite, BTX-A was injected into the anterior belly of the digastric muscle. Following injection of BTX-A, the anterior open bite showed immediate improvement. Complication and relapse were not observed during follow-up. Long-standing post-traumatic open bite could be successfully corrected by injection of BTX-A into the anterior belly of the digastric muscle without complication. PMID:24471041

  16. A Multi-Omics Approach Identifies Key Hubs Associated with Cell Type-Specific Responses of Airway Epithelial Cells to Staphylococcal Alpha-Toxin

    PubMed Central

    Richter, Erik; Harms, Manuela; Ventz, Katharina; Gierok, Philipp; Chilukoti, Ravi Kumar; Hildebrandt, Jan-Peter; Mostertz, Jörg; Hochgräfe, Falko

    2015-01-01

    Responsiveness of cells to alpha-toxin (Hla) from Staphylococcus aureus appears to occur in a cell-type dependent manner. Here, we compare two human bronchial epithelial cell lines, i.e. Hla-susceptible 16HBE14o- and Hla-resistant S9 cells, by a quantitative multi-omics strategy for a better understanding of Hla-induced cellular programs. Phosphoproteomics revealed a substantial impact on phosphorylation-dependent signaling in both cell models and highlights alterations in signaling pathways associated with cell-cell and cell-matrix contacts as well as the actin cytoskeleton as key features of early rHla-induced effects. Along comparable changes in down-stream activity of major protein kinases significant differences between both models were found upon rHla-treatment including activation of the epidermal growth factor receptor EGFR and mitogen-activated protein kinases MAPK1/3 signaling in S9 and repression in 16HBE14o- cells. System-wide transcript and protein expression profiling indicate induction of an immediate early response in either model. In addition, EGFR and MAPK1/3-mediated changes in gene expression suggest cellular recovery and survival in S9 cells but cell death in 16HBE14o- cells. Strikingly, inhibition of the EGFR sensitized S9 cells to Hla indicating that the cellular capacity of activation of the EGFR is a major protective determinant against Hla-mediated cytotoxic effects. PMID:25816343

  17. Ultrasound-Guided Injection of Botulinum Toxin Type A for Piriformis Muscle Syndrome: A Case Report and Review of the Literature

    PubMed Central

    Santamato, Andrea; Micello, Maria Francesca; Valeno, Giovanni; Beatrice, Raffaele; Cinone, Nicoletta; Baricich, Alessio; Picelli, Alessandro; Panza, Francesco; Logroscino, Giancarlo; Fiore, Pietro; Ranieri, Maurizio

    2015-01-01

    Piriformis muscle syndrome (PMS) is caused by prolonged or excessive contraction of the piriformis muscle associated with pain in the buttocks, hips, and lower limbs because of the close proximity to the sciatic nerve. Botulinum toxin type A (BoNT-A) reduces muscle hypertonia as well as muscle contracture and pain inhibiting substance P release and other inflammatory factors. BoNT-A injection technique is important considering the difficult access of the needle for deep location, the small size of the muscle, and the proximity to neurovascular structures. Ultrasound guidance is easy to use and painless and several studies describe its use during BoNT-A administration in PMS. In the present review article, we briefly updated current knowledge regarding the BoNT therapy of PMS, describing also a case report in which this syndrome was treated with an ultrasound-guided injection of incobotulinumtoxin A. Pain reduction with an increase of hip articular range of motion in this patient with PMS confirmed the effectiveness of BoNT-A injection for the management of this syndrome. PMID:26266421

  18. Change of Distribution and Timing of Bite Force after Botulinum Toxin Type A Injection Evaluated by a Computerized Occlusion Analysis System

    PubMed Central

    Song, Ji Hee; Cho, Eunae S.; Kim, Seong Taek

    2014-01-01

    Purpose The aim of this study was to determine the force distribution and pattern of mastication after injection of botulinum toxin type A (BTX-A) into both masseter muscles. The hypothesis to be tested was that the difference between right and left balance of occlusal force diminishes over time following BTX-A injection. Materials and Methods Fifteen patients were submitted to BTX-A injection therapy for subjective masseter hypertrophy. A total of 25 U of BTX-A (50 U in total) was injected into two points located 1 cm apart at the center of the lower one-third of both masseter muscles. All patients were examined using the T-Scan occlusion analysis system before and 4, 8, 12, and 24 weeks after BTX-A injection. Results A significant change in force balance was found between the right and left sides over time and the difference between the two sides decreased with the time post-injection, reaching a minimum at 12 weeks. Comparison of the force balance between the anterior and posterior occlusions revealed no significant difference at any of the time points. The occlusion and disclusion times (right and left sides) did not differ significantly with time since BTX-A injection. Conclusion A decline in the difference in the clenching force between the left and right sides was found with increasing time up to 12 weeks following BTX-A injection. PMID:24954346

  19. The Efficacy and Safety of Fractional CO2 Laser Combined with Topical Type A Botulinum Toxin for Facial Rejuvenation: A Randomized Controlled Split-Face Study

    PubMed Central

    Zhu, Jie; Ji, Xi; Li, Min; Chen, Xiao-e; Liu, Juan; Zhang, Jia-an; Luo, Dan; Zhou, Bing-rong

    2016-01-01

    Objective. We evaluated synergistic efficacy and safety of combined topical application of Botulinum Toxin Type A (BTX-A) with fractional CO2 laser for facial rejuvenation. Methods. Twenty female subjects were included for this split-face comparative study. One side of each subject's cheek was treated with fractional CO2 plus saline solution, and the other side was treated with fractional CO2 laser plus topical application of BTX-A. Patients received one session of treatment and evaluations were done at baseline, one, four, and twelve weeks after treatment. The outcome assessments included subjective satisfaction scale; blinded clinical assessment; and the biophysical parameters of roughness, elasticity, skin hydration, transepidermal water loss (TEWL), and the erythema and melanin index. Results. BTX-A combined with fractional CO2 laser sides showed higher physician's global assessment score, subject satisfaction score, roughness, skin hydration, and skin elasticity compared to that of fractional CO2 plus saline solution side at 12 weeks after treatment. TEWL and erythema and melanin index showed no significant differences between two sides at baseline, one, four, and twelve weeks after treatment. Conclusion. Topical application of BTX-A could enhance the rejuvenation effect of fractional CO2 laser. PMID:26998485

  20. Development of camelid single chain antibodies against Shiga toxin type 2 (Stx2) with therapeutic potential against Hemolytic Uremic Syndrome (HUS).

    PubMed

    Mejías, Maria P; Hiriart, Yanina; Lauché, Constanza; Fernández-Brando, Romina J; Pardo, Romina; Bruballa, Andrea; Ramos, María V; Goldbaum, Fernando A; Palermo, Marina S; Zylberman, Vanesa

    2016-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) infections are implicated in the development of the life-threatening Hemolytic Uremic Syndrome (HUS). Despite the magnitude of the social and economic problems caused by STEC infections, no licensed vaccine or effective therapy is presently available for human use. Single chain antibodies (VHH) produced by camelids exhibit several advantages in comparison with conventional antibodies, making them promising tools for diagnosis and therapy. In the present work, the properties of a recently developed immunogen, which induces high affinity and protective antibodies against Stx type 2 (Stx2), were exploited to develop VHHs with therapeutic potential against HUS. We identified a family of VHHs against the B subunit of Stx2 (Stx2B) that neutralize Stx2 in vitro at subnanomolar concentrations. One VHH was selected and was engineered into a trivalent molecule (two copies of anti-Stx2B VHH and one anti-seroalbumin VHH). The resulting molecule presented extended in vivo half-life and high therapeutic activity, as demonstrated in three different mouse models of Stx2-toxicity: a single i.v. lethal dose of Stx2, several i.v. incremental doses of Stx2 and intragastrical STEC infection. This simple antitoxin agent should offer new therapeutic options for treating STEC infections to prevent or ameliorate HUS outcome. PMID:27118524

  1. Development of camelid single chain antibodies against Shiga toxin type 2 (Stx2) with therapeutic potential against Hemolytic Uremic Syndrome (HUS)

    PubMed Central

    Mejías, Maria P.; Hiriart, Yanina; Lauché, Constanza; Fernández-Brando, Romina J.; Pardo, Romina; Bruballa, Andrea; Ramos, María V.; Goldbaum, Fernando A.; Palermo, Marina S.; Zylberman, Vanesa

    2016-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) infections are implicated in the development of the life-threatening Hemolytic Uremic Syndrome (HUS). Despite the magnitude of the social and economic problems caused by STEC infections, no licensed vaccine or effective therapy is presently available for human use. Single chain antibodies (VHH) produced by camelids exhibit several advantages in comparison with conventional antibodies, making them promising tools for diagnosis and therapy. In the present work, the properties of a recently developed immunogen, which induces high affinity and protective antibodies against Stx type 2 (Stx2), were exploited to develop VHHs with therapeutic potential against HUS. We identified a family of VHHs against the B subunit of Stx2 (Stx2B) that neutralize Stx2 in vitro at subnanomolar concentrations. One VHH was selected and was engineered into a trivalent molecule (two copies of anti-Stx2B VHH and one anti-seroalbumin VHH). The resulting molecule presented extended in vivo half-life and high therapeutic activity, as demonstrated in three different mouse models of Stx2-toxicity: a single i.v. lethal dose of Stx2, several i.v. incremental doses of Stx2 and intragastrical STEC infection. This simple antitoxin agent should offer new therapeutic options for treating STEC infections to prevent or ameliorate HUS outcome. PMID:27118524

  2. Toxin I from the snake Dendroaspis polylepis polylepis: a highly specific blocker of one type of potassium channel in myelinated nerve fiber.

    PubMed

    Benoit, E; Dubois, J M

    1986-07-01

    Toxin I from the venom of the black mamba snake Dendroaspis polylepis polylepis specifically blocks one component of the K-current (IKf1) in the frog node of Ranvier, with a high affinity (Kd = 4 X 10(-10) M) without significantly affecting either the others components of the K current (IKf2 and IKs) or the Na-current. Moreover, for toxin concentrations corresponding to 10- or 100-fold the Kd value, the block was almost irreversible. PMID:2425902

  3. Immunization with BLS-Stx2B chimera totally protects dams from early pregnancy loss induced by Shiga toxin type 2 (Stx2) and confers anti-Stx2 immunity to the offspring.

    PubMed

    Sacerdoti, Flavia; Mejías, María P; Bruballa, Andrea C; Alvarez, Romina Soledad; Amaral, María M; Palermo, Marina S; Ibarra, Cristina

    2016-09-01

    Shiga toxin producing Escherichia coli (STEC) are bacterial pathogens involved in food-borne diseases. Shiga toxin (Stx) is the main virulence factor of STEC and is responsible for systemic complications including Hemolytic Uremic Syndrome (HUS). It has been previously demonstrated that Shiga toxin type 2 (Stx2) induces pregnancy loss in rats in early stage of pregnancy. The main purpose of this study was to determine if an active immunization prevents Stx2 mediated pregnancy loss and confers passive protective immunity to the offspring. For that purpose Sprague Dawley female rats were immunized with the chimera based on the enzyme lumazine synthase from Brucella spp. (BLS) and the B subunit of Shiga toxin 2 (Stx2B) named BLS-Stx2B. After immunization females were mated with males. At day 8 of gestation, dams were challenged intraperitoneally with a sublethal and abortifacient dose of Stx2. The immunization induced high anti-Stx2B-specific antibody titers in sera and most important, prevented pregnancy loss. Pups born and breastfeed by immunized dams had high anti-Stx2B-specific antibody titers in sera. Cross-fostering experiments indicated that passive protective immunity against Stx2 was transmitted through lactation. These results indicate that immunization of adult female rats with BLS-Stx2B prevents Stx2-induced pregnancy loss and confers anti Stx2 protective immunity to the offspring. PMID:27527816

  4. Genetic Relatedness and Novel Sequence Types of Non-O157 Shiga Toxin-Producing Escherichia coli Strains Isolated in Argentina

    PubMed Central

    Cadona, Jimena S.; Bustamante, Ana V.; González, Juliana; Sanso, A. Mariel

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen responsible for severe disease in humans such as hemolytic uremic syndrome (HUS) and cattle, the principal reservoir. Identification of the clones/lineages is important as several characteristics, among them propensity to cause disease varies with STEC phylogenetic origin. At present, we do not know what STEC clones, especially of non-O157:H7, are circulating in Argentina. To fill this knowledge gap we assessed the genetic diversity of STEC strains isolated in Argentina from various sources, mostly cattle and food, using multilocus sequence typing (MLST). Our objectives were to determine the phylogenetic relationships among strains and to compare them with strains from different geographic origins, especially with those from clinical human cases, in order to evaluate their potential health risk. A total of 59 STEC isolates from 41 serotypes were characterized by MLST. Analysis using EcMLST database identified 38 sequence types (ST), 17 (45%) of which were new STs detected in 18 serotypes. Fifteen out of 38 STs identified were grouped into 11 clonal groups (CGs) and, 23 not grouped in any of the defined CGs. Different STs were found in the same serotype. Results highlighted a high degree of phylogenetic heterogeneity among Argentinean strains and they showed that several cattle and food isolates belonged to the same STs that are commonly associated with clinical human cases in several geographical areas. STEC is a significant public health concern. Argentina has the highest incidence of HUS in the world and this study provides the first data about which STEC clones are circulating. Data showed that most of them might pose a serious zoonotic risk and this information is important for developing public health initiatives. However, the actual potential risk will be defined by the virulence profiles, which may differ among isolates belonging to the same ST.

  5. Genetic Relatedness and Novel Sequence Types of Non-O157 Shiga Toxin-Producing Escherichia coli Strains Isolated in Argentina.

    PubMed

    Cadona, Jimena S; Bustamante, Ana V; González, Juliana; Sanso, A Mariel

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen responsible for severe disease in humans such as hemolytic uremic syndrome (HUS) and cattle, the principal reservoir. Identification of the clones/lineages is important as several characteristics, among them propensity to cause disease varies with STEC phylogenetic origin. At present, we do not know what STEC clones, especially of non-O157:H7, are circulating in Argentina. To fill this knowledge gap we assessed the genetic diversity of STEC strains isolated in Argentina from various sources, mostly cattle and food, using multilocus sequence typing (MLST). Our objectives were to determine the phylogenetic relationships among strains and to compare them with strains from different geographic origins, especially with those from clinical human cases, in order to evaluate their potential health risk. A total of 59 STEC isolates from 41 serotypes were characterized by MLST. Analysis using EcMLST database identified 38 sequence types (ST), 17 (45%) of which were new STs detected in 18 serotypes. Fifteen out of 38 STs identified were grouped into 11 clonal groups (CGs) and, 23 not grouped in any of the defined CGs. Different STs were found in the same serotype. Results highlighted a high degree of phylogenetic heterogeneity among Argentinean strains and they showed that several cattle and food isolates belonged to the same STs that are commonly associated with clinical human cases in several geographical areas. STEC is a significant public health concern. Argentina has the highest incidence of HUS in the world and this study provides the first data about which STEC clones are circulating. Data showed that most of them might pose a serious zoonotic risk and this information is important for developing public health initiatives. However, the actual potential risk will be defined by the virulence profiles, which may differ among isolates belonging to the same ST. PMID:27625995

  6. Adhesive tape exfoliation: Why it works for graphene

    NASA Astrophysics Data System (ADS)

    Bohr, Jakob

    2015-03-01

    Single-crystal graphite can be cleaved by the use of an adhesive tape. This was also the initial route for obtaining graphene, a one-layer thick graphite slab. In this letter a few simple and fun considerations are presented in an attempt to shed some light on why this procedure is successful. In particular on the nature of the surprisingly small number of repetitive steps that are needed in order to obtain a single-layer slab. Two frameworks for exfoliation are investigated: parallel exfoliation involving repetitive simultaneous cleaving, the other, serial exfoliation, which involves the repetitive cleaving of a single chunk of graphite. For both cases, parallel and serial exfoliation, it is investigated how many generations of cleavages are needed. An approximate model with the probability distribution expressed as a simple closed form is presented and compared with the simulations.

  7. The Structures of Coiled-Coil Domains from Type III Secretion System Translocators Reveal Homology to Pore-Forming Toxins

    SciTech Connect

    Barta, Michael L.; Dickenson, Nicholas E.; Patil, Mrinalini; Keightley, Andrew; Wyckoff, Gerald J.; Picking, William D.; Picking, Wendy L.; Geisbrecht, Brian V.

    2012-03-26

    Many pathogenic Gram-negative bacteria utilize type III secretion systems (T3SSs) to alter the normal functions of target cells. Shigella flexneri uses its T3SS to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. The Shigella type III secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. Host altering effectors are secreted through this energized unidirectional conduit to promote bacterial invasion. The active needle tip complex of S. flexneri is composed of a tip protein, IpaD, and two pore-forming translocators, IpaB and IpaC. While the atomic structure of IpaD has been elucidated and studied, structural data on the hydrophobic translocators from the T3SS family remain elusive. We present here the crystal structures of a protease-stable fragment identified within the N-terminal regions of IpaB from S. flexneri and SipB from Salmonella enterica serovar Typhimurium determined at 2.1 {angstrom} and 2.8 {angstrom} limiting resolution, respectively. These newly identified domains are composed of extended-length (114 {angstrom} in IpaB and 71 {angstrom} in SipB) coiled-coil motifs that display a high degree of structural homology to one another despite the fact that they share only 21% sequence identity. Further structural comparisons also reveal substantial similarity to the coiled-coil regions of pore-forming proteins from other Gram-negative pathogens, notably, colicin Ia. This suggests that these mechanistically separate and functionally distinct membrane-targeting proteins may have diverged from a common ancestor during the course of pathogen-specific evolutionary events.

  8. Serotypes, Virulence Genes, and Intimin Types of Shiga Toxin (Verotoxin)-Producing Escherichia coli Isolates from Human Patients: Prevalence in Lugo, Spain, from 1992 through 1999

    PubMed Central

    Blanco, J. E.; Blanco, M.; Alonso, M. P.; Mora, A.; Dahbi, G.; Coira, M. A.; Blanco, J.

    2004-01-01

    We have analyzed the prevalence of Shiga toxin-producing Escherichia coli (STEC) in stool specimens of patients with diarrhea or other gastrointestinal alterations from the Xeral-Calde Hospital of Lugo City (Spain). STEC strains were detected in 126 (2.5%) of 5,054 cases investigated, with a progressive increase in the incidence from 0% in 1992 to 4.4% in 1999. STEC O157:H7 was isolated in 24 cases (0.5%), whereas non-O157 STEC strains were isolated from 87 patients (1.7%). STEC strains were (after Salmonella and Campylobacter strains) the third most frequently recovered enteropathogenic bacteria. A total of 126 human STEC isolates were characterized in this study. PCR showed that 43 (34%) isolates carried stx1 genes, 45 (36%) possessed stx2 genes and 38 (30%) carried both stx1 and stx2. A total of 88 (70%) isolates carried an ehxA enterohemolysin gene, and 70 (56%) isolates possessed an eae intimin gene (27 isolates with type γ1, 20 with type β1, 8 with type ζ, 5 with type γ2, and 3 with type ɛ). STEC isolates belonged to 41 O serogroups and 66 O:H serotypes, including 21 serotypes associated with hemolytic uremic syndrome and 30 new serotypes not previously reported among human STEC strains in other studies. Although the 126 STEC isolates belonged to 81 different seropathotypes (associations between serotypes and virulence genes), only four accounted for 31% of isolates. Seropathotype O157:H7 stx1 stx2 eae-γ1 ehxA was the most common (13 isolates) followed by O157:H7 stx2 eae-γ1 ehxA (11 isolates), O26:H11 stx1 eae-β1 ehxA (11 isolates), and O111:H- stx1 stx2 eae-γ2 ehxA (4 isolates). Our results suggest that STEC strains are a significant cause of human infections in Spain and confirm that in continental Europe, infections caused by STEC non-O157 strains are more common than those caused by O157:H7 isolates. The high prevalence of STEC strains (both O157:H7 and non-O157 strains) in human patients, and their association with serious complications

  9. Graphene Made by Mechanical Exfoliation of Graphite Intercalation Compound

    NASA Astrophysics Data System (ADS)

    Fukada, Seiya; Shintani, Yumi; Shimomura, Midori; Tahara, Fumiya; Yagi, Ryuta

    2012-08-01

    We report a method of making few-layer graphene flakes by mechanically exfoliating SbCl5-graphite intercalation compounds (GICs). The number of layers of exfoliated graphene flakes had a particular distribution relevant to the stage structure of the GICs. The carrier doping of the few-layer graphene flakes was about two orders of magnitude smaller than that expected from the stoichiometry of the GICs. The measured electric mobility was comparable to that made from pristine graphite.

  10. *CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Cyanobacteria, or blue-green algae, are naturally-occurring contaminants of surface waters worldwide. These photosynthesizing prokaryotes thrive in warm, shallow, nutrient-rich waters. Many produce potent toxins as secondary metabolites. Cyanobacteria toxins have been document...

  11. Botulinum toxin injection - larynx

    MedlinePlus

    Injection laryngoplasty; Botox-larynx: spasmodic dysphonia-BTX; Essential voice tremor (EVT)-btx; Glottic insufficiency; Percutaneous electromyography-guided botulinum toxin treatment; Percutaneous indirect laryngoscopy-guided botulinum toxin Treatment; ...

  12. Stool C. difficile toxin

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003590.htm Stool C. difficile toxin To use the sharing features on this page, please enable JavaScript. The stool C. difficile toxin test detects harmful substances produced by ...

  13. Evidence of viscoplastic behavior of exfoliated graphite nanofluids.

    PubMed

    Hermida-Merino, Carolina; Pérez-Rodríguez, Martín; Piñeiro, Manuel M; Pastoriza-Gallego, María José

    2016-02-17

    The rheological behavior of ethylene glycol-based nanofluids containing exfoliated graphite nanoplatelets has been carried out using a cone-plate Physica MCR rheometer. Initial experiments based on flow curves were carried out, the flow curves were based on the controlled shear stress model, these tests show that the studied nanofluids present non-Newtonian shear thinning behavior with yield stress. Furthermore, linear viscoelastic experiments were conducted in order to determine the viscoelastic behavior: using strain sweep and frequency sweep tests the storage and loss modulus were determined. The fractal dimension (Df) was estimated from the suspension static yield-stress and volume fraction (ϕ) dependence, and was determined to be Df = 2.36, a value consistent with a process of aggregation of RLCA type (reaction limited cluster aggregation). This value is unusual if compared with other nanofluids, and can be regarded as a result of the bidimensionality of the suspended nanoplatelets. Finally, creep-recovery tests and mechanical models confirm the viscoplastic nature of our nanofluids, a feature never shown so far for this type of systems, increasing the solid-like character in the range of concentrations studied if compared with other nanofluids reported in the literature. This is a result of the combination of a remarkable internal structure and strong interactions, which evidence an unexpected behaviour sharing many solid-like features. PMID:26822724

  14. Exfoliated multilayer MoTe2 field-effect transistors

    NASA Astrophysics Data System (ADS)

    Fathipour, S.; Ma, N.; Hwang, W. S.; Protasenko, V.; Vishwanath, S.; Xing, H. G.; Xu, H.; Jena, D.; Appenzeller, J.; Seabaugh, A.

    2014-11-01

    The properties of multilayer exfoliated MoTe2 field-effect transistors (FETs) on SiO2 were investigated for channel thicknesses from 6 to 44 monolayers (MLs). All transistors showed p-type conductivity at zero back-gate bias. For channel thicknesses of 8 ML or less, the transistors exhibited ambipolar characteristics. ON/OFF current ratio was greatest, 1 × 105, for the transistor with the thinnest channel, 6 ML. Devices showed a clear photoresponse to wavelengths between 510 and 1080 nm at room temperature. Temperature-dependent current-voltage measurements were performed on a FET with 30 layers of MoTe2. When the channel is turned-on and p-type, the temperature dependence is barrier-limited by the Au/Ti/MoTe2 contact with a hole activation energy of 0.13 eV. A long channel transistor model with Schottky barrier contacts is shown to be consistent with the common-source characteristics.

  15. Investigation of exfoliation joints in Navajo sandstone at the Zion National Park and in granite at the Yosemite National Park by tectonofractographic techniques

    SciTech Connect

    Bahat, D.; Grossenbacher, K.; Karasaki, K.

    1995-04-01

    Tectonofractographic techniques have been applied to the study of joint exfoliation in the Navajo sandstone at Zion National Park and in the granite at Yosemite National Park. New types of fracture surface morphologies have been observed which enabled the discerning of incipient joints and consequent fracture growth in these rocks. Incipient jointing in the sandstone is mostly manifested by elliptical and circular fractures (meters to tens meters across) initiating from independent origins. They interfere with each other and grow to larger circular fractures producing exfoliation surfaces up to hundreds of meters across. Less frequently, series of large concentric undulations demonstrate the propagation of a large fracture front producing exfoliation from an individual origin. One such fracture front reveals refraction of undulations at a layer boundary. Certain en echelon fringes surround the joint mirror plane with well defined rims of en echelons and hackles which enable the determination of the tensile fracture stress, {sigma}f. Arches in Zion National Park are ubiquitous in shape and size, revealing stages in their evolution by a mechanical process, which was associated with exfoliation, but independent of local faulting. Exfoliation and arching mostly occurred on vertical surfaces of N-NNW and NE sets of prominent joints, but there are also deviations from this general trend. In Yosemite National Park large exfoliations (hundreds of meters in size) developed on the El Capitan cliff by the interaction and merging of many previous smaller incipient joints that vary in size from meters to tens of meter.

  16. Intradermal injection of Botulinum toxin type A alleviates infraorbital nerve constriction-induced thermal hyperalgesia in an operant assay.

    PubMed

    Kumada, A; Matsuka, Y; Spigelman, I; Maruhama, K; Yamamoto, Y; Neubert, J K; Nolan, T A; Watanabe, K; Maekawa, K; Kamioka, H; Yamashiro, T; Kuboki, T; Oguma, K

    2012-01-01

    Recent studies have shown that infraorbital nerve constriction (IoNC)-induced mechanical allodynia has been attenuated by administration of highly purified 150-kDa Botulinum neurotoxin type A (BoNT/A). Here, we extend these studies to determine whether BoNT/A could attenuate IoNC-induced symptoms of thermal hyperalgesia. Instead of testing head withdrawal thresholds, a thermal operant assay was used to evaluate cortical processing of sensory input following IoNC. In this assay, a fasted rat's desire to obtain a food reward (sweetened condensed milk) is coupled to its ability to tolerate facial contact with a warm (45 °C) thermode. Bilateral IoNC decreased the ratio of thermode contact duration/event, which is an indicative of thermal hyperalgesia. BoNT/A injection intradermally in the area of infraorbital nerve (IoN) innervation 7 days after IoNC resulted in decreased number of facial contacts and increased the ratio of contact duration/event (measured at 14 days after IoNC). The BoNT/A (2-200 pg) effects were dose dependent and statistically significant at 100 and 200 pg (P < 0·05). Complete reversal of thermal hyperalgesia symptoms was obtained with a 200-pg dose, without affecting sham rat behaviour. Off-site (neck) injection of BoNT/A did not relieve thermal hyperalgesia, while co-injection of BoNT/A with a neutralising antibody in the area of IoN innervation prevented relief of thermal hyperalgesia. Neither IoNC nor BoNT/A injection affected operant assay parameters with a 24 °C thermode, indicating selectivity of thermal hyperalgesia measurements. These results strongly suggest that intradermal injection of BoNT/A in the area of IoN innervation alleviates IoNC-induced thermal hyperalgesia in an operant assay. PMID:21793870

  17. Detection of Protein Toxins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have focused on ricin, shiga-like toxin, botulinum neurotoxin (BoNT), and staphylococcal enterotoxin A (SEA), developing sensitive test methods for toxins and marker compounds in food matrices. Although animal models provide the best means for risk assessment, especially for crude toxins in compl...

  18. Supramolecular Approaches to Graphene: From Self-Assembly to Molecule-Assisted Liquid-Phase Exfoliation.

    PubMed

    Ciesielski, Artur; Samorì, Paolo

    2016-08-01

    Graphene, a one-atom thick two-dimensional (2D) material, is at the core of an ever-growing research effort due to its combination of unique mechanical, thermal, optical and electrical properties. Two strategies are being pursued for the graphene production: the bottom-up and the top-down. The former relies on the use of covalent chemistry approaches on properly designed molecular building blocks undergoing chemical reaction to form 2D covalent networks. The latter occurs via exfoliation of bulk graphite into individual graphene sheets. Amongst the various types of exfoliations exploited so far, ultrasound-induced liquid-phase exfoliation (UILPE) is an attractive strategy, being extremely versatile, up-scalable and applicable to a variety of environments. In this review, we highlight the recent developments that have led to successful non-covalent functionalization of graphene and how the latter can be exploited to promote the process of molecule-assisted UILPE of graphite. The functionalization of graphene with non-covalently interacting molecules, both in dispersions as well as in dry films, represents a promising and modular approach to tune various physical and chemical properties of graphene, eventually conferring to such a 2D system a multifunctional nature. PMID:26928750

  19. A live attenuated Salmonella Enteritidis secreting detoxified heat labile toxin enhances mucosal immunity and confers protection against wild-type challenge in chickens.

    PubMed

    Lalsiamthara, Jonathan; Kamble, Nitin Machindra; Lee, John Hwa

    2016-01-01

    A live attenuated Salmonella Enteritidis (SE) capable of constitutively secreting detoxified double mutant Escherichia coli heat labile toxin (dmLT) was developed. The biologically adjuvanted strain was generated via transformation of a highly immunogenic SE JOL1087 with a plasmid encoding dmLT gene cassette; the resultant strain was designated JOL1641. A balanced-lethal host-vector system stably maintained the plasmid via auxotrophic host complementation with a plasmid encoded aspartate semialdehyde dehydrogenase (asd) gene. Characterization by western blot assay revealed the dmLT subunit proteins in culture supernatants of JOL1641. For the investigation of adjuvanticity and protective efficacy, chickens were immunized via oral or intramuscular routes with PBS, JOL1087 and JOL1641. Birds immunized with JOL1641 showed significant (P ≤ 0.05) increases in intestinal SIgA production at the 1(st) and 2(nd) weeks post-immunization via oral and intramuscular routes, respectively. Interestingly, while both strains showed significant splenic protection via intramuscular immunization, JOL1641 outperformed JOL1087 upon oral immunization. Oral immunization of birds with JOL1641 significantly reduced splenic bacterial counts. The reduction in bacterial counts may be correlated with an adjuvant effect of dmLT that increases SIgA secretion in the intestines of immunized birds. The inclusion of detoxified dmLT in the strain did not cause adverse reactions to birds, nor did it extend the period of bacterial fecal shedding. In conclusion, we report here that dmLT could be biologically incorporated in the secretion system of a live attenuated Salmonella-based vaccine, and that this construction is safe and could enhance mucosal immunity, and protect immunized birds against wild-type challenge. PMID:27262338

  20. Anti-photoaging potential of Botulinum Toxin Type A in UVB-induced premature senescence of human dermal fibroblasts in vitro through decreasing senescence-related proteins.

    PubMed

    Permatasari, Felicia; Hu, Yan-yan; Zhang, Jia-an; Zhou, Bing-rong; Luo, Dan

    2014-04-01

    This study was aimed to evaluate the anti-photoaging effects of Botulinum Toxin Type A (BoNTA) in Ultraviolet B-induced premature senescence (UVB-SIPS) of human dermal fibroblasts (HDFs) in vitro and the underlying mechanism. We established a stress-induced premature senescence model by repeated subcytotoxic exposures to Ultraviolet B (UVB) irradiation. The aging condition was determined by cytochemical staining of senescence-associated β-galactosidase (SA-β-gal). The tumor suppressor and senescence-associated protein levels of p16(INK-4a), p21(WAF-1), and p53 were estimated by Western blotting. The G1 phase cell growth arrest was analyzed by flow cytometry. The mRNA expressions of p16, p21, p53, COL1a1, COL3a1, MMP1, and MMP3 were determined by real-time PCR. The level of Col-1, Col-3, MMP-1, and MMP-3 were determined by ELISA. Compared with the UVB-irradiated group, we found that the irradiated fibroblasts additionally treated with BoNTA demonstrated a decrease in the expression of SA-β-gal, a decrease in the level of tumor suppressor and senescence-associated proteins, a decrease in the G1 phase cell proportion, an increase in the production of Col-1 and Col-3, and a decrease in the secretion of MMP-1 and MMP-3, in a dose-dependent manner. Taken together, these results indicate that BoNTA significantly antagonizes premature senescence induced by UVB in HDFs in vitro, therefore potential of intradermal BoNTA injection as anti-photoaging treatment still remains a question. PMID:24727404

  1. Long-term effects of injection of botulinum toxin type A combined with home-based functional training for post-stroke patients with spastic upper limb hemiparesis.

    PubMed

    Takekawa, Toru; Abo, Masahiro; Ebihara, Kazuaki; Taguchi, Kensuke; Sase, Yousuke; Kakuda, Wataru

    2013-12-01

    The aim of this study was to assess the effects of botulinum toxin type A (BoNT-A) injection with home-based functional training for passive and active motor function, over a 6-month period in post-stroke patients with upper limb spasticity. We studied 190 patients with at least 6-month history of stroke. They received injections of BoNT-A in upper limb muscles and detailed one-to-one instructions for home-based functional training. At baseline (before therapy), and at 1-, 3- and 6-month follow-up, Fugl-Meyer assessment (FMA) and Wolf motor function test (WMFT) were used to assess active motor function, the modified Ashworth scale (MAS) for assessment of spasticity, and the range of motion (ROM) for passive motor function. The total score for upper limb and scores of categories A and B of the FMA increased significantly at 1, 3 and 6 months, while the FMA score for category D increased significantly at 3 and 6 months, but not at 1 month. Significant decreases in the MAS scores were noted in all muscles examined at 1, 3 and 6 months, compared with baseline. The ROM for elbow joint extension significantly improved at 1, 3, and 6 months, while that for wrist joint extension increased significantly at 1 month, but not 3 or 6 months, compared with baseline. The results suggest that comprehensive improvement of motor function requires improvement of motor function in the proximal part of the upper limb and that BoNT-A followed by rehabilitation reduces spasticity and improves motor function of fingers. PMID:23716062

  2. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells

    PubMed Central

    Desin, Taseen S.; Townsend, Hugh G.; Potter, Andrew A.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  3. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells.

    PubMed

    Desin, Taseen S; Townsend, Hugh G; Potter, Andrew A

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  4. Botulinum Toxin Type A and the Prevention of Hypertrophic Scars on the Maxillofacial Area and Neck: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Xiao, Wen-lin; Xu, Yao-xiang

    2016-01-01

    Background The purpose of the meta-analysis was to evaluate the efficiency of therapeutic botulinum toxin type A (BTX-A) in the prevention of maxillofacial and neck scars. Methods and Findings Information came from the following electronic databases: Medline, PubMed, Cochrane Library, and EMBASE (time was ended by August 31, 2015) to retrieve RCTs evaluating the effect of the BTX-A for hypertrophic scar on the maxillofacial or neck. All languages were included as long as they met the inclusion criteria. Here the effects of BTX-A were evaluated by comparing the width of the scar, patient satisfaction, and the visual analysis scores (VAS), respectively. Pooled weighted mean differences (WMDs), pooled odds ratios (ORs), and 95% confidence intervals (CI) were calculated. Nine RCTs covering a total of 539 patients were included. A statistically significant difference in scar width was identified between the BTX-A group and control group (non-BTX-A used) (WMD = -0.41, 95% CI = -0.68 to -0.14, P = 0.003). A statistically significant difference in patient satisfaction was observed between the BTX-A group and control group (OR = 25.76, 95% CI = 2.58 to 256.67, P = 0.006). And in patients regarding visual analysis scores (VAS), a statistically significant difference was also observed between the BTX-A group and control group (WMD = 1.30, 95% CI = 1.00 to 1.60, P < 0.00001). Conclusions This meta-analysis evaluates the efficacy of the BTX-A and confirms that BTX-A is a suitable potential therapy for the prevention of hypertrophic scars in patients in the maxillofacial and neck areas. PMID:26985661

  5. Preparation and preclinical evaluation of experimental group B streptococcus type III polysaccharide-cholera toxin B subunit conjugate vaccine for intranasal immunization.

    PubMed

    Shen, X; Lagergård, T; Yang, Y; Lindblad, M; Fredriksson, M; Holmgren, J

    2000-11-22

    Streptococcus group B (GBS) is usually carried asymptomatically in the vaginal tract of women and can be transferred to the newborn during parturition. Serum antibodies to the capsular polysaccharide (CPS) can prevent invasive diseases, whereas immunity acting at the mucosal surface may be more important to inhibit the mucosal colonization of GBS and thus the risk of infection for the newborn. We prepared different GBS type III CPS-protein conjugate vaccines and evaluated their systemic and mucosal immunogenicity in mice. GBS type III CPS was conjugated to tetanus toxoid (TT) or recombinant cholera toxin B subunit (rCTB) either directly or to rCTB indirectly via TT. The conjugation was performed by different methods: (1) CPS was coupled to TT with 1-ethyl-3 (3-dimethylaminopropyl)-carbodiimide (EDAC), using adipic acid dihydrazide (ADH) as a spacer; (2) CPS was conjugated with rCTB using reductive amination; or, (3) N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) was used to bind rCTB to the TT of the CPS-TT conjugate. Mice were immunized with these conjugates or purified CPS by subcutaneous (s.c.) and intranasal (i. n.) routes. Antibodies to GBS III in serum, lungs and vagina were measured with ELISA. All of the CPS-protein conjugates were superior to unconjugated CPS in eliciting CPS-specific immune responses in serum and mucosal tissue extracts. The conjugates, when administrated s.c., induced only IgG responses in serum, lung and vagina, while i.n. vaccination also elicited IgA responses in the lungs and vagina. The CPS-TT conjugate administrated i.n. induced a strong serum IgG, but only a weak mucosal IgA response, while the CPS-rCTB conjugate elicited high IgG as well as IgA antibodies in the lungs after i.n. immunization. GBS III CPS-TT conjugated with rCTB produced a strong systemic and local anti-CPSIII response after i.n. administration. Co-administration of CT as adjuvant enhanced the anti-CPS systemic and mucosal immune responses further after i

  6. Signaling through C/EBP homologous protein and death receptor 5 and calpain activation differentially regulate THP-1 cell maturation-dependent apoptosis induced by Shiga toxin type 1.

    PubMed

    Lee, Moo-Seung; Cherla, Rama P; Lentz, Erin K; Leyva-Illades, Dinorah; Tesh, Vernon L

    2010-08-01

    Shiga toxins (Stxs) induce apoptosis via activation of the intrinsic and extrinsic pathways in many cell types. Toxin-mediated activation of the endoplasmic reticulum (ER) stress response was shown to be instrumental in initiating apoptosis in THP-1 myeloid leukemia cells. THP-1 cells responded to Shiga toxin type 1 (Stx1) in a cell maturation-dependent manner, undergoing rapid apoptosis in the undifferentiated state but reduced and delayed apoptosis in differentiated cells. The onset of apoptosis was associated with calpain activation and changes in expression of C/EBP homologous protein (CHOP), Bcl-2 family members, and death receptor 5 (DR5). Ligation of DR5 by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) activates the extrinsic pathway of apoptosis. We show here that expression of TRAIL and DR5 is increased by Stx1 treatment. Addition of exogenous TRAIL enhances, and anti-TRAIL antibodies inhibit, Stx1-induced apoptosis of THP-1 cells. Silencing of CHOP or DR5 expression selectively prevented caspase activation, loss of mitochondrial membrane potential, and Stx1-induced apoptosis of macrophage-like THP-1 cells. In contrast, the rapid kinetics of apoptosis induction in monocytic THP-1 cells correlated with rates of calpain cleavage. The results suggest that CHOP-DR5 signaling and calpain activation differentially contribute to cell maturation-dependent Stx1-induced apoptosis. Inhibition of these signaling pathways may protect cells from Stx cytotoxicity. PMID:20515924

  7. Layered titanium diboride: towards exfoliation and electrochemical applications.

    PubMed

    Lim, Chee Shan; Sofer, Zdeněk; Mazánek, Vlastimil; Pumera, Martin

    2015-08-01

    Layered transition metal diborides (TMDB), amongst other refractory metal borides, are commonly employed for material fabrication such as wear- and corrosion-resistant coatings due to their impressive chemical stability and thermal conductivity. In spite of the wide scope of studies carried out on TMDB in the physical field, investigations on its electrochemistry remain limited. Since the physical properties play a vital role in any material's electrochemical behaviour, we explore the viability of the most popular form of titanium boride, layered TiB2, as catalysts for electrochemical energy reactions, including hydrogen evolution and oxygen reduction. Three types of TiB2 were compared in this work - TiB2 separately modified with sodium naphtalenide and butyllithium in an attempt to exfoliate TiB2 and unmodified TiB2. The electrocatalytic activity displayed by all three TiB2 materials provides a wider range of opportunities for the application of TiB2 in material studies. PMID:26137856

  8. Study design and methods of the BoTULS trial: a randomised controlled trial to evaluate the clinical effect and cost effectiveness of treating upper limb spasticity due to stroke with botulinum toxin type A

    PubMed Central

    Rodgers, Helen; Shaw, Lisa; Price, Christopher; van Wijck, Frederike; Barnes, Michael; Graham, Laura; Ford, Gary; Shackley, Phil; Steen, Nick

    2008-01-01

    Background Following a stroke, 55–75% of patients experience upper limb problems in the longer term. Upper limb spasticity may cause pain, deformity and reduced function, affecting mood and independence. Botulinum toxin is used increasingly to treat focal spasticity, but its impact on upper limb function after stroke is unclear. The aim of this study is to evaluate the clinical and cost effectiveness of botulinum toxin type A plus an upper limb therapy programme in the treatment of post stroke upper limb spasticity. Methods Trial design : A multi-centre open label parallel group randomised controlled trial and economic evaluation. Participants : Adults with upper limb spasticity at the shoulder, elbow, wrist or hand and reduced upper limb function due to stroke more than 1 month previously. Interventions : Botulinum toxin type A plus upper limb therapy (intervention group) or upper limb therapy alone (control group). Outcomes : Outcome assessments are undertaken at 1, 3 and 12 months. The primary outcome is upper limb function one month after study entry measured by the Action Research Arm Test (ARAT). Secondary outcomes include: spasticity (Modified Ashworth Scale); grip strength; dexterity (Nine Hole Peg Test); disability (Barthel Activities of Daily Living Index); quality of life (Stroke Impact Scale, Euroqol EQ-5D) and attainment of patient-selected goals (Canadian Occupational Performance Measure). Health and social services resource use, adverse events, use of other antispasticity treatments and patient views on the treatment will be compared. Participants are clinically reassessed at 3, 6 and 9 months to determine the need for repeat botulinum toxin type A and/or therapy. Randomisation : A web based central independent randomisation service. Blinding : Outcome assessments are undertaken by an assessor who is blinded to the randomisation group. Sample size : 332 participants provide 80% power to detect a 15% difference in treatment successes between

  9. Toxic shock syndrome toxin-1, not α-toxin, mediated Bundaberg fatalities.

    PubMed

    Mueller, Elizabeth A; Merriman, Joseph A; Schlievert, Patrick M

    2015-12-01

    The 1928 Bundaberg disaster is one of the greatest vaccine tragedies in history. Of 21 children immunized with a diphtheria toxin-antitoxin preparation contaminated with Staphylococcus aureus, 18 developed life-threatening disease and 12 died within 48  h. Historically, the deaths have been attributed to α-toxin, a secreted cytotoxin produced by most S. aureus strains, yet the ability of the Bundaberg contaminant microbe to produce the toxin has never been verified. For the first time, the ability of the original strain to produce α-toxin and other virulence factors is investigated. The study investigates the genetic and regulatory loci mediating α-toxin expression by PCR and assesses production of the cytotoxin in vitro using an erythrocyte haemolysis assay. This analysis is extended to other secreted virulence factors produced by the strain, and their sufficiency to cause lethality in New Zealand white rabbits is determined. Although the strain possesses a wild-type allele for α-toxin, it must have a defective regulatory system, which is responsible for the strain's minimal α-toxin production. The strain encodes and produces staphylococcal superantigens, including toxic shock syndrome toxin-1 (TSST-1), which is sufficient to cause lethality in patients. The findings cast doubt on the belief that α-toxin is the major virulence factor responsible for the Bundaberg fatalities and point to the superantigen TSST-1 as the cause of the disaster. PMID:26432699

  10. NanI Sialidase, CcpA, and CodY Work Together To Regulate Epsilon Toxin Production by Clostridium perfringens Type D Strain CN3718

    PubMed Central

    Li, Jihong; Freedman, John C.

    2015-01-01

    ABSTRACT Clostridium perfringens type D strains are usually associated with diseases of livestock, and their virulence requires the production of epsilon toxin (ETX). We previously showed (J. Li, S. Sayeed, S. Robertson, J. Chen, and B. A. McClane, PLoS Pathog 7:e1002429, 2011, http://dx.doi.org/10.1371/journal.ppat.1002429) that BMC202, a nanI null mutant of type D strain CN3718, produces less ETX than wild-type CN3718 does. The current study proved that the lower ETX production by strain BMC202 is due to nanI gene disruption, since both genetic and physical (NanI or sialic acid) complementation increased ETX production by BMC202. Furthermore, a sialidase inhibitor that interfered with NanI activity also reduced ETX production by wild-type CN3718. The NanI effect on ETX production was shown to involve reductions in codY and ccpA gene transcription levels in BMC202 versus wild-type CN3718. Similar to CodY, CcpA was found to positively control ETX production. A double codY ccpA null mutant produced even less ETX than a codY or ccpA single null mutant. CcpA bound directly to sequences upstream of the etx or codY start codon, and bioinformatics identified putative CcpA-binding cre sites immediately upstream of both the codY and etx start codons, suggesting possible direct CcpA regulatory effects. A ccpA mutation also decreased codY transcription, suggesting that CcpA effects on ETX production can be both direct and indirect, including effects on codY transcription. Collectively, these results suggest that NanI, CcpA, and CodY work together to regulate ETX production, with NanI-generated sialic acid from the intestines possibly signaling type D strains to upregulate their ETX production and induce disease. IMPORTANCE Clostridium perfringens NanI was previously shown to increase ETX binding to, and cytotoxicity for, MDCK host cells. The current study demonstrates that NanI also regulates ETX production via increased transcription of genes encoding the CodY and Ccp

  11. Clostridium perfringens epsilon toxin inhibits the gastrointestinal transit in mice.

    PubMed

    Losada-Eaton, D M; Fernandez-Miyakawa, M E

    2010-12-01

    Epsilon toxin produced by Clostridium perfringens type B and D is a potent toxin that is responsible for a highly fatal enterotoxemia in sheep and goats. In vitro, epsilon toxin produces contraction of the rat ileum as the result of an indirect action, presumably mediated through the autonomic nervous system. To examine the impact of epsilon toxin in the intestinal transit, gastric emptying (GE) and gastrointestinal transit (GIT) were evaluated after intravenous and oral administration of epsilon toxin in mice. Orally administered epsilon toxin produced a delay on the GIT. Inhibition of the small intestinal transit was observed as early as 1 h after the toxin was administered orally but the effects were not observed after 1 week. Epsilon toxin also produced an inhibition in GE and a delay on the GIT when relatively high toxin concentrations were given intravenously. These results indicate that epsilon toxin administered orally or intravenously to mice transitorily inhibits the GIT. The delay in the GIT induced by epsilon toxin could be relevant in the pathogenesis of C. perfringens type B and D enterotoxemia. PMID:20434186

  12. Comparison of four techniques for the detection of Clostridium perfringens type D epsilon toxin in intestinal contents and other body fluids of sheep and goats.

    PubMed

    Uzal, F A; Kelly, W R; Thomas, R; Hornitzky, M; Galea, F

    2003-03-01

    Polyclonal capture enzyme-linked immunosorbent assay (PC-ELISA), monoclonal capture ELISA (MC-ELISA), mouse neutralization test (MNT), and counterimmunoelectrophoresis (CIEP), were compared for their ability to detect epsilon toxin in intestinal contents and body fluids of sheep and goats. When used to evaluate intestinal contents of sheep artificially spiked with epsilon prototoxin, PC-ELISA detected 0.075 mouse lethal dose (MLD)50/ml, whereas the MNT, MC-ELISA, and CIEP detected 6, 25, and 50 MLD50/ml, respectively. Amounts of epsilon toxin detected by PC-ELISA, MC-ELISA, MNT, and CIEP in sheep pericardial fluid artificially spiked with epsilon prototoxin were 0.075, 0.75, 6, and 200 MLD50/ml, respectively. For assaying epsilon toxin in aqueous humor, PC-ELISA and MC-ELISA detected 0.075 MLD50/ml, whereas CIEP detected 200 MLD50/ml (MNT was not evaluated). When 51 samples of intestinal contents of sheep and goats (32 positive and 19 negative to MNT) were analyzed by the other 3 techniques, the relative sensitivity of PC-ELISA, MC-ELISA, and CIEP was 93.75, 84.37, and 37.50%, respectively. The specificity of PC-ELISA, MC-ELISA, and CIEP was 31.57, 57.89, and 84.21%, respectively. The absolute sensitivity of PC-ELISA, MC-ELISA, CIEP, and MNT was 90.90, 69.69, 15.15, and 54.54%. The absolute specificity of the 4 techniques was 100%. These results show that there is a marked inconsistency among techniques routinely used to detect Clostridium perfringens epsilon toxin. Until more consistent results are achieved, the diagnosis of enterotoxemia should not only be based solely on epsilon toxin detection, but also on clinical and pathological data. PMID:12661718

  13. Serotypes, virulence genes and intimin types of Shiga toxin (verocytotoxin)-producing Escherichia coli isolates from minced beef in Lugo (Spain) from 1995 through 2003

    PubMed Central

    Mora, Azucena; Blanco, Miguel; Blanco, Jesús E; Dahbi, Ghizlane; López, Cecilia; Justel, Paula; Alonso, María Pilar; Echeita, Aurora; Bernárdez, María Isabel; González, Enrique A; Blanco, Jorge

    2007-01-01

    Background Shiga toxin-producing Escherichia coli (STEC) have emerged as pathogens that can cause food-borne infections and severe and potentially fatal illnesses in humans, such as haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS). In Spain, like in many other countries, STEC strains have been frequently isolated from ruminants, and represent a significant cause of sporadic cases of human infection. In view of the lack of data on STEC isolated from food in Spain, the objectives of this study were to determine the level of microbiological contamination and the prevalence of STEC O157:H7 and non-O157 in a large sampling of minced beef collected from 30 local stores in Lugo city between 1995 and 2003. Also to establish if those STEC isolated from food possessed the same virulence profiles as STEC strains causing human infections. Results STEC were detected in 95 (12%) of the 785 minced beef samples tested. STEC O157:H7 was isolated from eight (1.0%) samples and non-O157 STEC from 90 (11%) samples. Ninety-six STEC isolates were further characterized by PCR and serotyping. PCR showed that 28 (29%) isolates carried stx1 genes, 49 (51%) possessed stx2 genes, and 19 (20%) both stx1 and stx2. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 43 (45%) and in 25 (26%) of the isolates, respectively. Typing of the eae variants detected four types: γ1 (nine isolates), β1 (eight isolates), ε1 (three isolates), and θ (two isolates). The majority (68%) of STEC isolates belonged to serotypes previously detected in human STEC and 38% to serotypes associated with STEC isolated from patients with HUS. Ten new serotypes not previously described in raw beef products were also detected. The highly virulent seropathotypes O26:H11 stx1 eae-β1, O157:H7 stx1stx2 eae-γ1 and O157:H7 stx2eae-γ1, which are the most frequently observed among STEC causing human infections in Spain, were detected in 10 of the 96 STEC isolates. Furthermore, phage typing

  14. Anthrax lethal toxin down-regulates type-IIA secreted phospholipase A(2) expression through MAPK/NF-kappaB inactivation.

    PubMed

    Raymond, Benoit; Ravaux, Lucas; Mémet, Sylvie; Wu, YongZheng; Sturny-Leclère, Aude; Leduc, Dominique; Denoyelle, Chantal; Goossens, Pierre L; Payá, Miguel; Raymondjean, Michel; Touqui, Lhousseine

    2010-04-15

    Bacillus anthracis, the etiological agent of anthrax, produces lethal toxin (LT) that displays a metallo-proteolytic activity toward the N-terminus of the MAPK-kinases. We have previously shown that secreted type-IIA phospholipase A(2) (sPLA(2)-IIA) exhibits potent anthracidal activity. In vitro expression of sPLA(2)-IIA in guinea pig alveolar macrophages (AMs), the major source of this enzyme in lung tissues, is inhibited by LT. Here, we examined the mechanisms involved in sPLA(2)-IIA inhibition by LT. We first showed that chemical inhibitors of p38 and ERK MAPKs reduced sPLA(2)-IIA expression in AMs indicating that these kinases play a role in sPLA(2)-IIA expression. LT inhibited IL-1beta-induced p38 phosphorylation as well as sPLA(2)-IIA promoter activity in CHO cells. Inhibition of sPLA(2)-IIA promoter activity was mimicked by co-transfection with dominant negative construct of p38 (DN-p38) and reversed by the active form of p38-MAPK (AC-p38). Both LT and DN-p38 decreased IL-1beta-induced NF-kappaB luciferase activity. This contrasted with the effect of AC-p38, which enhanced this activity. However, neither LT nor specific p-38 inhibitor interfered with LPS-induced IkappaBalpha degradation or NF-kappaB nuclear translocation in AMs. Subcutaneous administration of LT to guinea pig before LPS challenge reduced sPLA(2)-IIA levels in broncho-alveolar lavages and ears. We conclude that sPLA(2)-IIA expression is induced via a sequential MAPK-NF-kappaB activation and that LT inhibits this expression likely by interfering with the transactivation of NF-kappaB in the nucleus. This inhibition, which is operating both in vitro and in vivo, may represent a mechanism by which B. anthracis subvert host defense. PMID:19962969

  15. Botulinum toxin type a (150 kDa) decreases exaggerated neurotransmitter release from trigeminal ganglion neurons and relieves neuropathy behaviors induced by infraorbital nerve constriction.

    PubMed

    Kitamura, Y; Matsuka, Y; Spigelman, I; Ishihara, Y; Yamamoto, Y; Sonoyama, W; Kamioka, H; Yamashiro, T; Kuboki, T; Oguma, K

    2009-04-10

    Many patients with trigeminal neuropathies suffer severe chronic pain which is inadequately alleviated with centrally-acting drugs. These drugs also possess severe side effects making compliance difficult. One strategy is to develop new treatments without central side effects by targeting peripheral sensory neurons, since sensory neuron excitability and neurotransmitter release increase in chronic pain states. Such treatments may include the highly purified botulinum toxin type A 150 kDa (BoNT/A) which reportedly blocks vesicular neurotransmitter release. We set out to determine if experimental trigeminal neuropathy induced by infraorbital nerve constriction (IoNC) in rats could alter neurotransmitter release from somata of trigeminal sensory neurons and if it could be attenuated by BoNT/A. Thus, we monitored the secretory activity of acutely dissociated trigeminal ganglion (TRG) neurons from naïve and IoNC rats by measuring the fluorescence intensity of the membrane-uptake marker (N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide (FM4-64). FM4-64 staining showed that neurons possess a pool of recycled vesicles which could be released by high KCl (75 mM) application. BoNT/A pre-treatment of acutely dissociated TRG neurons from naïve rats significantly reduced the rate of FM4-64 dye release. Neurons isolated from TRG ipsilateral to IoNC exhibited significantly faster onset of FM4-64 release than neurons contralateral to IoNC (sham surgery). IoNC also produced long-lasting ipsilateral tactile allodynia, measured as large decreases of withdrawal thresholds to mechanical stimulation. Intradermal injection of BoNT/A in the area of infraorbital branch of the trigeminal nerve (IoN) innervation alleviated IoNC-induced mechanical allodynia and reduced the exaggerated FM4-64 release in TRG neurons from these rats. Our results suggest that BoNT/A decreases neuropathic pain behaviors by decreasing the exaggerated neurotransmitter

  16. Eight-Year Experience With Botulinum Toxin Type-A Injections for the Treatment of Nonneurogenic Overactive Bladder: Are Repeated Injections Worthwhile?

    PubMed Central

    Pathan, Sana

    2016-01-01

    Purpose: To investigate the efficacy and safety of repeated botulinum toxin type-A (BTX-A) injections for patients with drug-refractory nonneurogenic overactive bladder (NNOAB) and explore factors predictive of outcome. Methods: Data were collected from all patients receiving repeated BTX-A injections for drug-refractory NNOAB between 2004 and 2012. Trigone-sparing injections were administered under sedation with antibiotic prophylaxis. Patient characteristics including age, sex, preoperative urodynamics, injection number, BTX-A dose, complications, and patient global impression of improvement (PGI-I) scores were collected. Correlations between patient factors and outcomes were assessed by using Pearson’s chi-square tests. Results: Fifty-two patients with a mean age of 67.4 years (range, 26–93 years) received 140 BTX-A injections in total; 33 (64%), 15 (29%), and 4 patients (7%) received 2, 3 to 4, and 5 to 8 injections, respectively. Mean follow-up time was 49 months (range, 9–101 months). Nine patients developed urinary tract infection; additionally, 3 patients experienced transient urinary retention. Median PGI-I score was 2 out of 7 (interquartile range [IQR], 2). For 46 patients, the PGI-I score remained stable with the administration of each injection. Pearson chi-square tests revealed that male patients or reduced bladder compliance was associated with a higher (worse) PGI-I score. Median PGI-I scores for men and women were 3 (IQR, 1) and 2 (IQR, 1), respectively; additionally, median PGI-I scores for those with normal bladder compliance and those with reduced bladder compliance were 2 (IQR, 2) and 4.5 (IQR, 1), respectively. Median PGI-I scores and complication rates were the same in the older patient (≥70 years) and younger (<70 years) patient cohorts. Conclusions: Efficacy is maintained with repeated BTX-A injections. Patients including the elderly show a good degree of tolerability with a low complication rate. Male patients or reduced bladder

  17. Thermal Exfoliation of Natural Cellulosic Material for Graphene Synthesis

    NASA Astrophysics Data System (ADS)

    Ray, Ajoy Kumar; Chatterjee, Somenath; Singh, Jitendra Kumar; Bapari, Himangshu

    2015-01-01

    Hibiscus flower petals have been used as a cheap natural resource precursor for cost-effective synthesis of high quality graphene by thermal exfoliation process. In order to compare the quality of graphene obtained from the flower petals directly with the flower petals pretreated with nickel(II) chloride, Raman spectroscopic technique has been used as the structural probe. The role of temperature and the effect of nickel on thermal exfoliation process have been examined. It has been observed that graphene obtained via nickel incorporation is of better quality because NI2+ ions that get dispersed in the layered-structured cellulose at elevated temperatures get reduced to the metallic state, which in turn push the graphitic layers during thermal exfoliation to produce good quality graphene. In contrast, no such driving force is present in cellulose and hemi-cellulose of flower petals that contain lignin.

  18. [Intoxication of botulinum toxin].

    PubMed

    Chudzicka, Aleksandra

    2015-09-01

    Botulinum toxin is an egzotoxin produced by Gram positive bacteria Clostridium botulinum. It is among the most potent toxins known. The 3 main clinical presentations of botulism are as follows: foodborne botulism, infant botulism and wound botulism. The main symptom of intoxication is flat muscles paralysis. The treatment is supportive care and administration of antitoxin. In prevention the correct preparing of canned food is most important. Botulinum toxin is accepted as a biological weapon. PMID:26449577

  19. Inhibition of maize histone deacetylases by HC toxin, the host-selective toxin of Cochliobolus carbonum.

    PubMed Central

    Brosch, G; Ransom, R; Lechner, T; Walton, J D; Loidl, P

    1995-01-01

    HC toxin, the host-selective toxin of the maize pathogen Cochliobolus carbonum, inhibited maize histone deacetylase (HD) at 2 microM. Chlamydocin, a related cyclic tetrapeptide, also inhibited HD activity. The toxins did not affect histone acetyltransferases. After partial purification of histone deacetylases HD1-A, HD1-B, and HD2 from germinating maize embryos, we demonstrated that the different enzymes were similarly inhibited by the toxins. Inhibitory activities were reversibly eliminated by treating toxins with 2-mercaptoethanol, presumably by modifying the carbonyl group of the epoxide-containing amino acid Aeo (2-amino-9,10-epoxy-8-oxodecanoic acid). Kinetic studies revealed that inhibition of HD was of the uncompetitive type and reversible. HC toxin, in which the epoxide group had been hydrolyzed, completely lost its inhibitory activity; when the carbonyl group of Aeo had been reduced to the corresponding alcohol, the modified toxin was less active than native toxin. In vivo treatment of embryos with HC toxin caused the accumulation of highly acetylated histone H4 subspecies and elevated acetate incorporation into H4 in susceptible-genotype embryos but not in the resistant genotype. HDs from chicken and the myxomycete Physarum polycephalum were also inhibited, indicating that the host selectivity of HC toxin is not determined by its inhibitory effect on HD. Consistent with these results, we propose a model in which HC toxin promotes the establishment of pathogenic compatibility between C. carbonum and maize by interfering with reversible histone acetylation, which is implicated in the control of fundamental cellular processes, such as chromatin structure, cell cycle progression, and gene expression. PMID:8535144

  20. Formation mechanisms and near-surface stress orientations derived from fractographic markings on exfoliation joints in the Alps

    NASA Astrophysics Data System (ADS)

    Ziegler, M.; Loew, S.; Bahat, D.

    2013-12-01

    Granitic bedrock of the upper Aar valley (Grimsel area, Swiss Alps) contains four distinct exfoliation joint generations, which formed during different stages of the Pleistocene and occur in an Alpine landscape between inner trough valley bottoms and high mountain crests. Exfoliation joints of this investigation likely formed during the Middle Pleistocene (0.7-0.4 Ma; batch 1) and Upper Pleistocene to Holocene (<0.1 Ma; batch 2), subparallel to distinct glacial valley (palaeo-)topography. Mapping revealed that exfoliation joints of these batches exhibit prominent fracture surface morphologies. The bulk of exfoliation joints of batches 1 and 2 show common, characteristic fractographic features: (1) noncircular, radial plumose structures, (2) arrest marks on parent fracture planes and fringe cracks, and (3) gradually-developing fringe zones of en échelon type (Figure 1). We interpret smooth transitions from plumose structures on the parent plane to en échelon fringe cracks, combined with non-systematic stepping senses of fringe cracks, as local stress field variations (vs. temporal variations) in the vicinity of pre-existing joints and faults. Multiple arrest marks reveal that exfoliation joints in the Grimsel area formed incrementally and, together with absence of hackle fringes, suggest stable fracture conditions. Furthermore, we put special emphasis on surveying the orientations of plumose structure axes. We assume that plumose structure axes formed parallel to the maximum principal (far-field) compressive stress (σ1). This enables us to infer near-surface stress orientations within Alpine slopes. We found a correlation between the orientations of plumose structure axes and slope aspects for batches 1 and 2. Primarily low pitch angles (<~30°) of plumose structure axes suggest persistently subhorizontal to slightly inclined σ1 orientations, i.e. the orientation of σ1 changes together with change in slope aspect. We attribute this surface-near variability of

  1. Botulinum toxin injection - larynx

    MedlinePlus

    Injection laryngoplasty; Botox-larynx: spasmodic dysphonia-BTX; Essential voice tremor (EVT)-btx; Glottic insufficiency; Percutaneous electromyography-guided botulinum toxin treatment; Percutaneous indirect laryngoscopy- ...

  2. Preliminary spectroscopic characterization of six toxins from Latin American scorpions.

    PubMed

    Possani, L; Steinmetz, W E; Dent, M A; Alagón, A C; Wüthrich, K

    1981-07-28

    This paper reports on spectroscopic studies of six toxins from the Latin American scorpions Centruroides noxius Hoffmann, Centruroides elegans Thorell and Tityus serrulatus Lutz and Mello. The isolation and purification of five of these toxins was described previously. The preparation of toxin II.9.2.2 from the venom of C. noxius is first described here. Circular dichroism and nuclear magnetic resonance spectra indicate similarities and differences between these scorpion toxins and previously characterized snake toxins. While there is evidence that the toxins from scorpions and snakes both contain extended beta-sheet secondary structures, the spectral properties of the scorpion toxins are overall of a different type from those of snake toxins. Among the six scorpion toxins those from T. serrulatus have spectral properties markedly different from those of the Centruroides species. Furthermore, thermal denaturation and amide proton exchange measurements showed that the globular structures of the Tityus toxins were markedly less stable and less rigid than those of the Centruroides toxins. PMID:7284435

  3. Botulinum Toxin Type A Induces Changes in the Chemical Coding of Substance P-Immunoreactive Dorsal Root Ganglia Sensory Neurons Supplying the Porcine Urinary Bladder

    PubMed Central

    Bossowska, Agnieszka; Lepiarczyk, Ewa; Mazur, Urszula; Janikiewicz, Paweł; Markiewicz, Włodzimierz

    2015-01-01

    Botulinum toxin (BTX) is a potent neurotoxin which blocks acetylcholine release from nerve terminals, and therefore leads to cessation of somatic motor and/or parasympathetic transmission. Recently it has been found that BTX also interferes with sensory transmission, thus, the present study was aimed at investigating the neurochemical characterization of substance P-immunoreactive (SP-IR) bladder-projecting sensory neurons (BPSN) after the toxin treatment. Investigated neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against SP, calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), galanin (GAL), calbindin (CB), and somatostatin (SOM). In the control group (n = 6), 45% of the total population of BPSN were SP-IR. Nearly half of these neurons co-expressed PACAP or CGRP (45% and 35%, respectively), while co-localization of SP with GAL, nNOS, SOM or CB was found less frequently (3.7%, 1.8%, 1.2%, and 0.7%, respectively). In BTX-treated pigs (n = 6), toxin-injections caused a decrease in the number of SP-IR cells containing CGRP, SOM or CB (16.2%, 0.5%, and 0%, respectively) and a distinct increase in these nerve cells immunopositive to GAL (27.2%). The present study demonstrates that BTX significantly modifies the chemical phenotypes of SP-IR BPSN. PMID:26580655

  4. Botulinum toxin type A induces changes in the chemical coding of substance P-immunoreactive dorsal root ganglia sensory neurons supplying the porcine urinary bladder.

    PubMed

    Bossowska, Agnieszka; Lepiarczyk, Ewa; Mazur, Urszula; Janikiewicz, Paweł; Markiewicz, Włodzimierz

    2015-11-01

    Botulinum toxin (BTX) is a potent neurotoxin which blocks acetylcholine release from nerve terminals, and therefore leads to cessation of somatic motor and/or parasympathetic transmission. Recently it has been found that BTX also interferes with sensory transmission, thus, the present study was aimed at investigating the neurochemical characterization of substance P-immunoreactive (SP-IR) bladder-projecting sensory neurons (BPSN) after the toxin treatment. Investigated neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against SP, calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), galanin (GAL), calbindin (CB), and somatostatin (SOM). In the control group (n = 6), 45% of the total population of BPSN were SP-IR. Nearly half of these neurons co-expressed PACAP or CGRP (45% and 35%, respectively), while co-localization of SP with GAL, nNOS, SOM or CB was found less frequently (3.7%, 1.8%, 1.2%, and 0.7%, respectively). In BTX-treated pigs (n = 6), toxin-injections caused a decrease in the number of SP-IR cells containing CGRP, SOM or CB (16.2%, 0.5%, and 0%, respectively) and a distinct increase in these nerve cells immunopositive to GAL (27.2%). The present study demonstrates that BTX significantly modifies the chemical phenotypes of SP-IR BPSN. PMID:26580655

  5. Antibodies against recombinant shiga toxin subunit B neutralize shiga toxin toxicity in HeLa cells.

    PubMed

    Gupta, Pallavi; Singh, Manglesh Kumar; Singh, Padma; Tiwari, Mugdha; Dhaked, Ram Kumar

    2010-06-01

    Shigella dysenteriae type 1 and Escherichia coli O157:H7 produce Shiga toxin 1 (Stx) and Shiga toxin1 (Stx1), respectively and these two toxins are almost identical. E. coli O157:H7 is the major cause of diarrhea-associated hemolytic uremic syndrome. Stx and Stx1 are AB5 type of toxin with a molecular weight of 70 kDa, comprising an enzymaticaly-active A subunit (32 kDa) and five receptor-binding B subunits (7.7 kDa). In this study DNA fragment (289 bp, Gene Bank Accn No. EF685161) coding for B chain of Stx was amplified from S. dysenteriae type1 and cloned. Shiga toxin-binding subunit was expressed and purified in native conditions by affinity and gel permeation chromatography with the yield of 5.1 mg/L in shake flask culture. For the purpose of immunization, the polypeptide was polymerized with glutaraldehyde. Hyper immune serum produced in mice reacted with the purified polypeptide and intact Shiga toxin. The anti-StxB antiserum effectively neutralized the cytotoxicity of Shiga toxin towards HeLa cells. PMID:20044923

  6. Toxin-Antitoxin Systems of Staphylococcus aureus.

    PubMed

    Schuster, Christopher F; Bertram, Ralph

    2016-01-01

    Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery. PMID:27164142

  7. Toxin-Antitoxin Systems of Staphylococcus aureus

    PubMed Central

    Schuster, Christopher F.; Bertram, Ralph

    2016-01-01

    Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery. PMID:27164142

  8. Sulfur-doped graphene via thermal exfoliation of graphite oxide in H2S, SO2, or CS2 gas.

    PubMed

    Poh, Hwee Ling; Šimek, Petr; Sofer, Zdeněk; Pumera, Martin

    2013-06-25

    Doping of graphene with heteroatoms is an effective way to tailor its properties. Here we describe a simple and scalable method of doping graphene lattice with sulfur atoms during the thermal exfoliation process of graphite oxides. The graphite oxides were first prepared by Staudenmaier, Hofmann, and Hummers methods followed by treatments in hydrogen sulfide, sulfur dioxide, or carbon disulfide. The doped materials were characterized by scanning electron microscopy, high-resolution X-ray photoelectron spectroscopy, combustible elemental analysis, and Raman spectroscopy. The ζ-potential and conductivity of sulfur-doped graphenes were also investigated in this paper. It was found that the level of doping is more dramatically influenced by the type of graphite oxide used rather than the type of sulfur-containing gas used during exfoliation. Resulting sulfur-doped graphenes act as metal-free electrocatalysts for an oxygen reduction reaction. PMID:23656223

  9. Defense against toxin weapons

    SciTech Connect

    Franz, D.R.

    1994-01-01

    The purpose of this manual is to provide basic information on biological toxins to military leaders and health-care providers at all levels to help them make informed decisions on protecting their troops from toxins. Much of the information contained herein will also be of interest to individuals charged with countering domestic and international terrorism. We typically fear what we do not understand.

  10. NMR and restrained molecular dynamics study of the three-dimensional solution structure of toxin FS2, a specific blocker of the L-type calcium channel, isolated from black mamba venom.

    PubMed

    Albrand, J P; Blackledge, M J; Pascaud, F; Hollecker, M; Marion, D

    1995-05-01

    The three-dimensional solution structure of toxin FS2, a 60-residue polypeptide isolated from the venom of black mamba snake (Dendroaspis polylepis polylepis), has been determined by nuclear magnetic resonance spectroscopy. Using 600 NOE constraints and 55 dihedral angle constraints, a set of 20 structures obtained from distance-geometry calculations was further refined by molecular dynamics calculations using a combined simulated annealing-restrained MD protocol. The resulting 20 conformers, taken to represent the solution structure, give an average rmsd of 1.2 A for their backbone atoms, relative to the average structure. The overall resulting three-fingered structure is similar to those already observed in several postsynaptic neurotoxins, cardiotoxins, and fasciculins, which all share with toxin FS2 the same network of four disulfide bridges. The overall concavity of the molecule, considered as a flat bottomed dish, is oriented toward the C-terminal loop of the molecule. This orientation is similar to that of fasciculins and cardiotoxins but opposite to that of neurotoxins. On the basis of the local rms displacements between the 20 conformers, the structure of the first loop appears to be less well defined in FS2 than in the previously reported neurotoxin structures, but fasciculin 1 shows a similar trend with particularly high temperature factors for this part of the X-ray structure. The concave side which presents most of the positively charged residues is quite similar in FS2 and fasciculin 1. The main difference is shown by the convex side of the third loop, mostly hydrophobic in FS2, in contrast to the pair of negatively charged aspartates in fasciculin 1. This difference could be one of the factors leading to the distinct pharmacological properties-L-type calcium channel blocker for FS2 and cholinesterase inhibitor for fasciculin--observed for these two subgroups of the "angusticeps-type" toxins. PMID:7727450

  11. Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation.

    PubMed

    Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

    2016-01-01

    Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors. PMID:27026070

  12. Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation

    NASA Astrophysics Data System (ADS)

    Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

    2016-03-01

    Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors.

  13. Preparation of colloidal graphene in quantity by electrochemical exfoliation.

    PubMed

    Chen, Kunfeng; Xue, Dongfeng

    2014-12-15

    We reported the preparation of colloidal graphene in quantity via the anodic exfoliation of graphite in (NH4)2SO4 aqueous solution. In the currently designed electrochemical exfoliation route, mass high-quality graphene was produced within short reaction time, around 1h. The proposed electrochemical exfoliation mechanism showed that SO4(2-) and H2O can be intercalated into those graphite sheets, monolayer and few-layer graphene were obtained by the formation of gaseous SO2 and O2 within graphite sheets. Stability evaluation showed that our exfoliated colloidal graphene can be perfectly stabilized in DMF solvent more than 1 week. The colloidal graphene can be used to construct various simple and complex patterns by writing it on A4 paper, which can be applied to flexible printed electronic devices. Furthermore, colloidal graphene can show promising applications in the fabrication of binder- and additive-free electrodes for supercapacitors and lithium-ion batteries. Our present method shows huge potential for industrial-scale synthesis of high-quality graphene and further commercialization of graphene colloid for numerous advanced applications in flexible printed electronics and energy storage devices. PMID:25265584

  14. Determination of dimensions of exfoliating materials in aqueous suspensions.

    PubMed

    Karpovich, Anastasia L; Vlasova, Maria F; Sapronova, Natalya I; Sukharev, Valentin S; Ivanov, Victor V

    2016-01-01

    A method for measurement of dimensions of platy particles of exfoliating, or delaminating, materials, such as clays, in aqueous suspensions in situ is proposed. Equivalent spherical diameter (esd), measured by many common methods, depends more on the major (lateral) dimension of a particle, while it is less sensitive to changes of the particle thickness. Addition of the second method, results of which are a function of the particle diameter and thickness too, would provide more accurate determination of the particle dimensions. Previously, a combination of low-temperature nitrogen adsorption (BET) and dynamic light scattering (DLS) methods for determination of specific surface area of dry powder of platy particles and their esd in suspension was suggested. While such combination was suitable for measurement of particle size for non-exfoliating materials, it gave incorrect results for exfoliating materials, which dramatically change their surface area when dispersed in liquid. We modify this method by substituting BET method with NMR relaxometry, which allows to measure wetted surface area of the dispersed material directly in suspension. The advantages of this method are:•More accurate determination of diameter and thickness of platy, particularly exfoliating, materials directly in suspension.•Possibility of routine monitoring of particle size changes during the dispersing process. PMID:27408825

  15. Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation

    PubMed Central

    Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

    2016-01-01

    Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors. PMID:27026070

  16. Automotive body panel containing thermally exfoliated graphite oxide

    NASA Technical Reports Server (NTRS)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Adamson, Douglas (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    An automotive body panel containing a polymer composite formed of at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

  17. High-quality thin graphene films from fast electrochemical exfoliation.

    PubMed

    Su, Ching-Yuan; Lu, Ang-Yu; Xu, Yanping; Chen, Fu-Rong; Khlobystov, Andrei N; Li, Lain-Jong

    2011-03-22

    Flexible and ultratransparent conductors based on graphene sheets have been considered as one promising candidate for replacing currently used indium tin oxide films that are unlikely to satisfy future needs due to their increasing cost and losses in conductivity on bending. Here we demonstrate a simple and fast electrochemical method to exfoliate graphite into thin graphene sheets, mainly AB-stacked bilayered graphene with a large lateral size (several to several tens of micrometers). The electrical properties of these exfoliated sheets are readily superior to commonly used reduced graphene oxide, which preparation typically requires many steps including oxidation of graphite and high temperature reduction. These graphene sheets dissolve in dimethyl formamide (DMF), and they can self-aggregate at air-DMF interfaces after adding water as an antisolvent due to their strong surface hydrophobicity. Interestingly, the continuous films obtained exhibit ultratransparency (∼96% transmittance), and their sheet resistance is <1k Ω/sq after a simple HNO3 treatment, superior to those based on reduced graphene oxide or graphene sheets by other exfoliation methods. Raman and STM characterizations corroborate that the graphene sheets exfoliated by our electrochemical method preserve the intrinsic structure of graphene. PMID:21309565

  18. Shiga toxins: from structure and mechanism to applications.

    PubMed

    Chan, Yau Sang; Ng, Tzi Bun

    2016-02-01

    Shiga toxins are a group of type 2 ribosome-inactivating proteins (RIPs) produced in several types of bacteria. The toxins possess an AB5 structure, which comprises a catalytic A chain with N-glycosidase activity, and five identical B chains and recognize and bind to the target cells with specific carbohydrate moieties. In humans, the major molecular target which recognizes the Shiga toxins is the Gb3 receptor, which is mainly expressed on the cell surface of endothelial cells of the intestine, kidney, and the brain. This causes these organs to be susceptible to the toxicity of Shiga toxins. When a person is infected by Shiga toxin-producing bacteria, the toxin is produced in the gut, translocated to the circulatory system, and carried to the target cells. Toxicity of the toxin causes inflammatory responses and severe cell damages in the intestine, kidneys, and brain, bringing about the hemolytic uremic syndrome (HUS), which can be fatal. The Shiga toxin requires a couple of steps to exert its toxicity to the target cells. After binding with the target cell surface receptor, the toxin requires a complicated process to be transported into the cytosol of the cell before it can approach the ribosomes. The mechanisms for the interactions of the toxin with the cells are described in this review. The consequences of the toxin on the cells are also discussed. It gives an overview of the steps for the toxin to be produced and transported, expression of catalytic activity, and the effects of the toxin on the target cells, as well as effects on the human body. PMID:26685676

  19. Bacterial Toxins and the Nervous System: Neurotoxins and Multipotential Toxins Interacting with Neuronal Cells

    PubMed Central

    Popoff, Michel R.; Poulain, Bernard

    2010-01-01

    Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons. PMID:22069606

  20. MoS{sub 2} nanotube exfoliation as new synthesis pathway to molybdenum blue

    SciTech Connect

    Visic, B.; Gunde, M. Klanjsek; Kovac, J.; Iskra, I.; Jelenc, J.; Remskar, M.

    2013-02-15

    Graphical abstract: . Display Omitted Highlights: ► New synthesis approach to obtaining molybdenum blue via exfoliated MoS{sub 2} nanotubes. ► Material is prone to self assembly and is stable in high vacuum. ► Molecules are as small as 2 nm and their clusters are up to tens of nanometers. ► Change in absorption and oxidation states from the precursor MoS{sub 2}. -- Abstract: Molybdenum blue-type materials are usually obtained by partially reducing Mo{sup VI+} in acidic solutions, while in the presented method it is formed in ethanol solution of exfoliated MoS{sub 2} nanotubes, where the MoS{sub 2} flakes are the preferential location for their growth. Material was investigated by means of scanning electron and atomic force microscopy, showing the structure and self assembly, while also confirming that it is stable in high vacuum with molecules as small as 1.6 nm and the agglomerates of few tens of nanometres. The ultraviolet–visible and photoelectron spectrometry show the change in absorption properties and oxidation states from MoS{sub 2} structure to molybdenum blue, while the presence of sulphur suggests that this is a new type of molybdenum blue material.

  1. Morphological and electrical properties of epoxy-based composites reinforced with exfoliated graphite

    NASA Astrophysics Data System (ADS)

    Lamberti, Patrizia; Spinelli, Giovanni; Tucci, Vincenzo; Guadagno, Liberata; Raimondo, Marialuigia; Vertuccio, Luigi

    2016-05-01

    An experimental study has been carried out to prepare and characterize epoxy/amine-based composites filled with different percentages of partially exfoliated graphite (i.e. pEG) particles having an exfoliation degree of 56% in order to analyze the effect of the filler amounts on the electrical properties of the resulting nanocomposites. Moreover, in order to fully investigate the direct relationship between the physical properties of the employed filler and the results of the electrical characterization, a structural and morphological characterization of the pEG samples is carried out by means of various type of analysis such as X-ray diffraction patterns, micro-Raman and Scanning Electron Microscopy (SEM) images. The DC electrical characterization reveals a percolation thresholds (EPT) that falls in the range [2-3] wt% and an electrical conductivity of about 0.66 S/m at the highest filler loading (6.5 wt%). From the analysis of the percolative curve it is possible to derive the percolation law parameters and in particular the critical exponent t, whose value (i.e. 1.2) reflects an effective 2D organization of the percolating structure consistent with the type of filler used (2-dimensional). Finally, an extensive analysis concerning the electrical properties in the frequency domain has been carried out in order to evaluate the effectiveness of pEG-loaded composites in terms of electromagnetic interference compatibility (EMC) and their applicability as radar absorbers materials (RAMs).

  2. Understanding malarial toxins.

    PubMed

    Starkl Renar, Katarina; Iskra, Jernej; Križaj, Igor

    2016-09-01

    Recognized since antiquity, malaria is one of the most infamous and widespread infectious diseases in humans and, although the death rate during the last century has been diminishing, it still accounts for more than a half million deaths annually. It is caused by the Plasmodium parasite and typical symptoms include fever, shivering, headache, diaphoresis and nausea, all resulting from an excessive inflammatory response induced by malarial toxins released into the victim's bloodstream. These toxins are hemozoin and glycosylphosphatidylinositols. The former is the final product of the parasite's detoxification of haeme, a by-product of haemoglobin catabolism, while the latter anchor proteins to the Plasmodium cell surface or occur as free molecules. Currently, only two groups of antimalarial toxin drugs exist on the market, quinolines and artemisinins. As we describe, they both target biosynthesis of hemozoin. Other substances, currently in various phases of clinical trials, are directed towards biosynthesis of glycosylphosphatidylinositol, formation of hemozoin, or attenuation of the inflammatory response of the patient. Among the innovative approaches to alleviating the effects of malarial toxins, is the development of antimalarial toxin vaccines. In this review the most important lessons learned from the use of treatments directed against the action of malarial toxins in antimalarial therapy are emphasized and the most relevant and promising directions for future research in obtaining novel antimalarial agents acting on malarial toxins are discussed. PMID:27353131

  3. Toxin-Deficient Mutants from a Toxin-Sensitive Transformant of Cochliobolus Heterostrophus

    PubMed Central

    Yang, G.; Turgeon, B. G.; Yoder, O. C.

    1994-01-01

    Tox1 is the only genetic element identified which controls production of T-toxin, a linear polyketide involved in the virulence of Cochliobolus heterostrophus to its host plant, corn. Previous attempts to induce toxin-deficient (Tox(-)) mutants, using conventional mutagenesis and screening procedures, have been unsuccessful. As a strategy to enrich for Tox(-) mutants, we constructed a Tox1(+) strain that carried the corn T-urf13 gene (which confers T-toxin sensitivity) fused to a fungal mitochondrial signal sequence; the fusion was under control of the inducible Aspergillus nidulans pelA promoter which, in both A. nidulans and C. heterostrophus, is repressed by glucose and induced by polygalacturonic acid (PGA). We expected that a transformant carrying this construction would be sensitive to its own toxin when the T-urf13 gene was expressed. Indeed, the strain grew normally on medium containing glucose but was inhibited on medium containing PGA. Conidia of this strain were treated with ethylmethanesulfonate and plated on PGA medium. Among 362 survivors, 9 were defective in T-toxin production. Authenticity of each mutant was established by the presence of the transformation vector, proper mating type, and a restiction fragment length polymorphism tightly linked to the Tox1(+) locus. Progeny of each mutant crossed to a Tox1(+) tester segregated 1:1 (for wild type toxin production vs. no or reduced toxin production), indicating a single gene mutation in each case. Progeny of each mutant crossed to a Tox1(-) tester segregated 1 : 1 (for no toxin production vs. no or reduced toxin production) indicating that each mutation mapped at the Tox1 locus. Availability of Tox(-) mutants will permit mapping in the Tox1 region without interference from a known Tox1 linked translocation breakpoint. PMID:8088521

  4. Crystal Structure of Botulinum Neurotoxin Type a in Complex With the Cell Surface Co-Receptor GT1b-Insight Into the Toxin-Neuron Interaction

    SciTech Connect

    Stenmark, P.; Dupuy, J.; Inamura, A.; Kiso, M.; Stevens, R.C.

    2009-05-26

    Botulinum neurotoxins have a very high affinity and specificity for their target cells requiring two different co-receptors located on the neuronal cell surface. Different toxin serotypes have different protein receptors; yet, most share a common ganglioside co-receptor, GT1b. We determined the crystal structure of the botulinum neurotoxin serotype A binding domain (residues 873-1297) alone and in complex with a GT1b analog at 1.7 A and 1.6 A, respectively. The ganglioside GT1b forms several key hydrogen bonds to conserved residues and binds in a shallow groove lined by Tryptophan 1266. GT1b binding does not induce any large structural changes in the toxin; therefore, it is unlikely that allosteric effects play a major role in the dual receptor recognition. Together with the previously published structures of botulinum neurotoxin serotype B in complex with its protein co-receptor, we can now generate a detailed model of botulinum neurotoxin's interaction with the neuronal cell surface. The two branches of the GT1b polysaccharide, together with the protein receptor site, impose strict geometric constraints on the mode of interaction with the membrane surface and strongly support a model where one end of the 100 A long translocation domain helix bundle swing into contact with the membrane, initiating the membrane anchoring event.

  5. Recent insights into Clostridium perfringens beta-toxin.

    PubMed

    Nagahama, Masahiro; Ochi, Sadayuki; Oda, Masataka; Miyamoto, Kazuaki; Takehara, Masaya; Kobayashi, Keiko

    2015-02-01

    Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT) that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin. PMID:25654787

  6. Recent Insights into Clostridium perfringens Beta-Toxin

    PubMed Central

    Nagahama, Masahiro; Ochi, Sadayuki; Oda, Masataka; Miyamoto, Kazuaki; Takehara, Masaya; Kobayashi, Keiko

    2015-01-01

    Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT) that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin. PMID:25654787

  7. Sea Anemone (Cnidaria, Anthozoa, Actiniaria) Toxins: An Overview

    PubMed Central

    Frazão, Bárbara; Vasconcelos, Vitor; Antunes, Agostinho

    2012-01-01

    The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines), but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects) and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na+ and K+ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins. PMID:23015776

  8. Sea anemone (Cnidaria, Anthozoa, Actiniaria) toxins: an overview.

    PubMed

    Frazão, Bárbara; Vasconcelos, Vitor; Antunes, Agostinho

    2012-08-01

    The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines), but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects) and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na⁺ and K⁺ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins. PMID:23015776

  9. Expression of functional diphtheria toxin receptors on highly toxin-sensitive mouse cells that specifically bind radioiodinated toxin.

    PubMed Central

    Naglich, J G; Rolf, J M; Eidels, L

    1992-01-01

    Diphtheria toxin (DT), a bacterial protein exotoxin, inactivates mammalian cell elongation factor 2 after toxin internalization by receptor-mediated endocytosis. To isolate the DT receptor, we cotransfected DT-resistant wild-type mouse L-M cells with a cDNA library constructed from RNA of highly toxin-sensitive monkey Vero cells and with a neomycin-resistance gene. Stably transfected G418-resistant L-M colonies were screened for DT sensitivity in a replica plate assay. After screening of 8000 colonies, one DT-sensitive (DTS) colony was isolated. The purified DTS mouse cells are highly toxin-sensitive; they are at least 1000-fold more sensitive than wild-type L-M cells and only approximately 10-fold less sensitive than Vero cells. Incubation of the DTS mouse cells with CRM 197, a nontoxic form of DT that competitively inhibits the binding of native DT to the toxin receptor, protected them from DT-mediated toxicity. More important, these DTS mouse cells express receptors on their cell surface that bind radioiodinated DT in a specific fashion, a property hitherto readily demonstrable only with highly toxin-sensitive cells of monkey origin. Furthermore, HA6DT, a DT fragment comprising the Mr 6000 carboxyl-terminal receptor-binding domain, inhibited the binding of radioiodinated toxin to these DTS mouse cells to the same extent as unlabeled DT. With these DTS mouse cells as a source of monkey cDNA, it should be possible to clone the gene encoding the DT receptor. PMID:1549577

  10. Purification, crystallization and preliminary X-ray analysis of an HA17–HA70 (HA2–HA3) complex from Clostridium botulinum type C progenitor toxin

    PubMed Central

    Iwasa, Chikako; Tonozuka, Takashi; Shinoda, Masaya; Sagane, Yoshimasa; Niwa, Koichi; Watanabe, Toshihiro; Yoshida, Hiromi; Kamitori, Shigehiro; Takao, Toshifumi; Oguma, Keiji; Nishikawa, Atsushi

    2014-01-01

    The haemagglutinin (HA) complex of Clostridium botulinum type C toxin is composed of three types of subcomponents: HA33, HA17 and HA70 (also known as HA1, HA2 and HA3, respectively). Here, a 260 kDa HA17–HA70 complex was crystallized. His-tagged HA17 and maltose-binding-protein-tagged HA70 were expressed in Escherichia coli and their complex was affinity-purified using a combination of amylose resin chromatography and nickel–nitrilotri­acetic acid agarose chromatography. Diffraction data were collected to 8.0 Å resolution and the crystal belonged to the tetragonal space group P41212. The molecular-replacement solution indicated that one molecule of HA17 was bound to each HA70 monomer. PMID:24419620

  11. Alpha-Toxin and Gamma-Toxin Jointly Promote Staphylococcus aureus Virulence in Murine Septic Arthritis

    PubMed Central

    Nilsson, Ing-Marie; Hartford, Orla; Foster, Timothy; Tarkowski, Andrzej

    1999-01-01

    Septic arthritis is a common and feared complication of staphylococcal infections. Staphylococcus aureus produces a number of potential virulence factors including certain adhesins and enterotoxins. In this study we have assessed the roles of cytolytic toxins in the development of septic arthritis by inoculating mice with S. aureus wild-type strain 8325-4 or isogenic mutants differing in the expression of alpha-, beta-, and gamma-toxin production patterns. Mice inoculated with either an alpha- or beta-toxin mutant showed degrees of inflammation, joint damage, and weight decrease similar to wild-type-inoculated mice. In contrast, mice inoculated with either double (alpha- and gamma-toxin-deficient)- or triple (alpha-, beta-, and gamma-toxin-deficient)-mutant S. aureus strains showed lower frequency and severity of arthritis, measured both clinically and histologically, than mice inoculated with the wild-type strain. We conclude that simultaneous production of alpha- and gamma-toxin is a virulence factor in S. aureus arthritis. PMID:10024541

  12. ANALYSES OF WOUND EXUDATES FOR CLOSTRIDIAL TOXINS.

    PubMed

    NOYES, H E; PRITCHARD, W L; BRINKLEY, F B; MENDELSON, J A

    1964-03-01

    Noyes, Howard E. (Walter Reed Army Institute of Research, Washington, D.C.), William L. Pritchard, Floyd B. Brinkley, and Janice A. Mendelson. Analyses of wound exudates for clostridial toxins. J. Bacteriol. 87:623-629. 1964.-Earlier studies indicated that death of goats with traumatic wounds of the hindquarter could be related to the number of clostridia in the wounds, and that toxicity of wound exudates for mice and guinea pigs could be partially neutralized by commercial trivalent gas gangrene antitoxin. This report describes in vitro and in vivo analyses of wound exudates for known clostridial toxins. Wounds were produced by detonation of high-explosive pellets. Wound exudates were obtained by cold saline extraction of both necrotic tissues and gauze sponges used to cover the wounds. Exudates were sterilized by Seitz filtration in the cold. In vitro tests were used to measure alpha-, theta-, and mu-toxins of Clostridium perfringens and the epsilon-toxin of C. novyi. Mouse protection tests, employing commercial typing antisera, were used to analyze exudates for other clostridial toxins. Lethality of wound exudates for mice could be related to (i) the numbers of clostridia present in the wound, (ii) survival time of the goats, and (iii) positive lecithovitellin (LV) tests of the exudates. However, the LV tests could not be neutralized by antitoxin specific for C. perfringens alpha-toxin. Mice were not protected by typing antisera specific for types A, C, or D C. perfringens or C. septicum but were protected by antisera specific for type B C. perfringens and types A and B C. novyi. PMID:14127581

  13. Dynamics and Mechanisms of Exfoliated Black Phosphorus Sublimation.

    PubMed

    Fortin-Deschênes, Matthieu; Levesque, Pierre L; Martel, Richard; Moutanabbir, Oussama

    2016-05-01

    We report on real time observations of the sublimation of exfoliated black phosphorus layers throughout annealing using in situ low energy electron microscopy. We found that sublimation manifests itself above 375 ± 20 °C through the nucleation and expansion of asymmetric, faceted holes with the long axis aligned along the [100] direction and sharp tips defined by edges consisting of alternating (10) and (11) steps. This thermally activated process repeats itself via successive sublimation of individual layers. Calculations and simulations using density functional theory and kinetic Monte Carlo allowed to determine the involved atomic pathways. Sublimation is found to occur via detachments of phosphorus dimers rather than single atoms. This behavior and the role of defects is described using an analytical model that captures all essential features. This work establishes an atomistic-level understanding of the thermal stability of exfoliated black phosphorus and defines the temperature window available for material and device processing. PMID:27097073

  14. Chemical vapor deposition-derived graphene with electrical performance of exfoliated graphene.

    PubMed

    Petrone, Nicholas; Dean, Cory R; Meric, Inanc; van der Zande, Arend M; Huang, Pinshane Y; Wang, Lei; Muller, David; Shepard, Kenneth L; Hone, James

    2012-06-13

    While chemical vapor deposition (CVD) promises a scalable method to produce large-area graphene, CVD-grown graphene has heretofore exhibited inferior electronic properties in comparison with exfoliated samples. Here we test the electrical transport properties of CVD-grown graphene in which two important sources of disorder, namely grain boundaries and processing-induced contamination, are substantially reduced. We grow CVD graphene with grain sizes up to 250 μm to abate grain boundaries, and we transfer graphene utilizing a novel, dry-transfer method to minimize chemical contamination. We fabricate devices on both silicon dioxide and hexagonal boron nitride (h-BN) dielectrics to probe the effects of substrate-induced disorder. On both substrate types, the large-grain CVD graphene samples are comparable in quality to the best reported exfoliated samples, as determined by low-temperature electrical transport and magnetotransport measurements. Small-grain samples exhibit much greater variation in quality and inferior performance by multiple measures, even in samples exhibiting high field-effect mobility. These results confirm the possibility of achieving high-performance graphene devices based on a scalable synthesis process. PMID:22582828

  15. Characterizing Edge and Stacking Structures of Exfoliated Graphene by Photoelectron Diffraction

    NASA Astrophysics Data System (ADS)

    Matsui, Fumihiko; Ishii, Ryo; Matsuda, Hiroyuki; Morita, Makoto; Kitagawa, Satoshi; Matsushita, Tomohiro; Koh, Shinji; Daimon, Hiroshi

    2013-11-01

    The two-dimensional C 1s photoelectron intensity angular distributions (PIADs) and spectra of exfoliated graphene flakes and crystalline graphite were measured using a focused soft X-ray beam. Suitable graphene samples were selected by thickness characterization using Raman spectromicroscopy after transferring mechanically exfoliated graphene flakes onto a 90-nm-thick SiO2 film. In every PIAD, a Kagomé interference pattern was observed, particularly clearly in the monolayer graphene PIAD. Its origin is the overlap of the diffraction rings formed by an in-plane C-C bond honeycomb lattice. Thus, the crystal orientation of each sample can be determined. In the case of bilayer graphene, PIAD was threefold-symmetric, while those of monolayer graphene and crystalline graphite were sixfold-symmetric. This is due to the stacking structure of bilayer graphene. From comparisons with the multiple scattering PIAD simulation results, the way of layer stacking as well as the termination types in the edge regions of bilayer graphene flakes were determined. Furthermore, two different C 1s core levels corresponding to the top and bottom layers of bilayer graphene were identified. A chemical shift to a higher binding energy by 0.25 eV for the bottom layer was attributed to interfacial interactions.

  16. Sensitive detection of active Shiga toxin using low cost CCD based optical detector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To reduce the sources and incidence of food-borne illness there is a need to develop inexpensive sensitive devices for detection of active toxin, such as Shiga toxin type 2 (Stx2). This approach increases the availability of foodborne bacterial toxin diagnostics in regions where there are limited r...

  17. Exfoliated MoS2 in Water without Additives

    PubMed Central

    Forsberg, Viviane; Zhang, Renyun; Bäckström, Joakim; Dahlström, Christina; Andres, Britta; Norgren, Magnus; Andersson, Mattias; Hummelgård, Magnus; Olin, Håkan

    2016-01-01

    Many solution processing methods of exfoliation of layered materials have been studied during the last few years; most of them are based on organic solvents or rely on surfactants and other funtionalization agents. Pure water should be an ideal solvent, however, it is generally believed, based on solubility theories that stable dispersions of water could not be achieved and systematic studies are lacking. Here we describe the use of water as a solvent and the stabilization process involved therein. We introduce an exfoliation method of molybdenum disulfide (MoS2) in pure water at high concentration (i.e., 0.14 ± 0.01 g L−1). This was achieved by thinning the bulk MoS2 by mechanical exfoliation between sand papers and dispersing it by liquid exfoliation through probe sonication in water. We observed thin MoS2 nanosheets in water characterized by TEM, AFM and SEM images. The dimensions of the nanosheets were around 200 nm, the same range obtained in organic solvents. Electrophoretic mobility measurements indicated that electrical charges may be responsible for the stabilization of the dispersions. A probability decay equation was proposed to compare the stability of these dispersions with the ones reported in the literature. Water can be used as a solvent to disperse nanosheets and although the stability of the dispersions may not be as high as in organic solvents, the present method could be employed for a number of applications where the dispersions can be produced on site and organic solvents are not desirable. PMID:27120098

  18. Exfoliated MoS2 in Water without Additives.

    PubMed

    Forsberg, Viviane; Zhang, Renyun; Bäckström, Joakim; Dahlström, Christina; Andres, Britta; Norgren, Magnus; Andersson, Mattias; Hummelgård, Magnus; Olin, Håkan

    2016-01-01

    Many solution processing methods of exfoliation of layered materials have been studied during the last few years; most of them are based on organic solvents or rely on surfactants and other funtionalization agents. Pure water should be an ideal solvent, however, it is generally believed, based on solubility theories that stable dispersions of water could not be achieved and systematic studies are lacking. Here we describe the use of water as a solvent and the stabilization process involved therein. We introduce an exfoliation method of molybdenum disulfide (MoS2) in pure water at high concentration (i.e., 0.14 ± 0.01 g L-1). This was achieved by thinning the bulk MoS2 by mechanical exfoliation between sand papers and dispersing it by liquid exfoliation through probe sonication in water. We observed thin MoS2 nanosheets in water characterized by TEM, AFM and SEM images. The dimensions of the nanosheets were around 200 nm, the same range obtained in organic solvents. Electrophoretic mobility measurements indicated that electrical charges may be responsible for the stabilization of the dispersions. A probability decay equation was proposed to compare the stability of these dispersions with the ones reported in the literature. Water can be used as a solvent to disperse nanosheets and although the stability of the dispersions may not be as high as in organic solvents, the present method could be employed for a number of applications where the dispersions can be produced on site and organic solvents are not desirable. PMID:27120098

  19. Lignin-assisted exfoliation of molybdenum disulfide in aqueous media and its application in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Liu, Wanshuang; Zhao, Chenyang; Zhou, Rui; Zhou, Dan; Liu, Zhaolin; Lu, Xuehong

    2015-05-01

    In this article, alkali lignin (AL)-assisted direct exfoliation of MoS2 mineral into single-layer and few-layer nanosheets in water is reported for the first time. Under optimized conditions, the concentration of MoS2 nanosheets in the obtained dispersion can be as high as 1.75 +/- 0.08 mg mL-1, which is much higher than the typical reported concentrations (<1.0 mg mL-1) using synthetic polymers or compounds as surfactants. The stabilizing mechanism primarily lies in the electrostatic repulsion between negative charged AL, as suggested by zeta-potential measurements. When the exfoliated MoS2 nanosheets are applied as electrode materials for lithium ion batteries, they show much improved electrochemical performance compared with the pristine MoS2 mineral because of the enhanced ion and electron transfer kinetics. This facile, scalable and eco-friendly aqueous-based process in combination with renewable and ultra-low-cost lignin opens up possibilities for large-scale fabrication of MoS2-based nanocomposites and devices. Moreover, herein we demonstrate that AL is also an excellent surfactant for exfoliation of many other types of layered materials, including graphene, tungsten disulfide and boron nitride, in water, providing rich opportunities for a wider range of applications.In this article, alkali lignin (AL)-assisted direct exfoliation of MoS2 mineral into single-layer and few-layer nanosheets in water is reported for the first time. Under optimized conditions, the concentration of MoS2 nanosheets in the obtained dispersion can be as high as 1.75 +/- 0.08 mg mL-1, which is much higher than the typical reported concentrations (<1.0 mg mL-1) using synthetic polymers or compounds as surfactants. The stabilizing mechanism primarily lies in the electrostatic repulsion between negative charged AL, as suggested by zeta-potential measurements. When the exfoliated MoS2 nanosheets are applied as electrode materials for lithium ion batteries, they show much improved

  20. Regulation of toxin gene expression in Clostridium perfringens.

    PubMed

    Ohtani, Kaori; Shimizu, Tohru

    2015-05-01

    The Gram-positive, anaerobic, spore-forming, rod-shaped Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tract of humans and animals. C. perfringens causes clostridial myonecrosis (or gas gangrene), enteritis and enterotoxemia in humans and livestock by producing numerous extracellular toxins and enzymes. The toxin gene expression is regulated by a two-component regulatory system and regulatory RNA VirR/VirS-VR-RNA cascade. The VirR/VirS system was originally found in a type A strain, but a recent report showed that it is also important for the toxin gene regulation in other types of strains. Two types of cell-cell signaling, i.e., agr-system and AI-2 signaling, are also important for the regulation of toxin genes. Several regulatory systems independent from the VirR/VirS system, including virX, the orphan histidine kinase ReeS and orphan response regulator RevR, are also involved in the regulation of toxin genes. In addition, the expression of toxin genes is upregulated after contact with Caco-2 cells. C. perfringens has a complex regulatory network for toxin gene expression and thus the coordination of toxin gene expression is important for the process of infection. PMID:25303832

  1. Exfoliation of large-area transition metal chalcogenide single layers

    PubMed Central

    Magda, Gábor Zsolt; Pető, János; Dobrik, Gergely; Hwang, Chanyong; Biró, László P.; Tapasztó, Levente

    2015-01-01

    Isolating large-areas of atomically thin transition metal chalcogenide crystals is an important but challenging task. The mechanical exfoliation technique can provide single layers of the highest structural quality, enabling to study their pristine properties and ultimate device performance. However, a major drawback of the technique is the low yield and small (typically < 10 μm) lateral size of the produced single layers. Here, we report a novel mechanical exfoliation technique, based on chemically enhanced adhesion, yielding MoS2 single layers with typical lateral sizes of several hundreds of microns. The idea is to exploit the chemical affinity of the sulfur atoms that can bind more strongly to a gold surface than the neighboring layers of the bulk MoS2 crystal. Moreover, we found that our exfoliation process is not specific to MoS2, but can be generally applied for various layered chalcogenides including selenites and tellurides, providing an easy access to large-area 2D crystals for the whole class of layered transition metal chalcogenides. PMID:26443185

  2. Exfoliation of Hexagonal Boron Nitride via Ferric Chloride Intercalation

    NASA Technical Reports Server (NTRS)

    Hung, Ching-cheh; Hurst, Janet; Santiago, Diana; Rogers, Richard B.

    2014-01-01

    Sodium fluoride (NaF) was used as an activation agent to successfully intercalate ferric chloride (FeCl3) into hexagonal boron nitride (hBN). This reaction caused the hBN mass to increase by approx.100 percent, the lattice parameter c to decrease from 6.6585 to between 6.6565 and 6.6569 ?, the x-ray diffraction (XRD) (002) peak to widen from 0.01deg to 0.05deg of the full width half maximum value, the Fourier transform infrared (FTIR) spectrum's broad band (1277/cm peak) to change shape, and new FTIR bands to emerge at 3700 to 2700 and 1600/cm. This indicates hBN's structural and chemical properties are significantly changed. The intercalated product was hygroscopic and interacted with moisture in the air to cause further structural and chemical changes (from XRD and FTIR). During a 24-h hold at room temperature in air with 100 percent relative humidity, the mass increased another 141 percent. The intercalated product, hydrated or not, can be heated to 750 C in air to cause exfoliation. Exfoliation becomes significant after two intercalation-air heating cycles, when 20-nm nanosheets are commonly found. Structural and chemical changes indicated by XRD and FTIR data were nearly reversed after the product was placed in hydrochloric acid (HCl), resulting in purified, exfoliated, thin hBN products.

  3. Ultrahigh-throughput exfoliation of graphite into pristine ‘single-layer’ graphene using microwaves and molecularly engineered ionic liquids

    NASA Astrophysics Data System (ADS)

    Matsumoto, Michio; Saito, Yusuke; Park, Chiyoung; Fukushima, Takanori; Aida, Takuzo

    2015-09-01

    Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards ‘single-layer’ graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml-1, and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

  4. Lignin-assisted exfoliation of molybdenum disulfide in aqueous media and its application in lithium ion batteries.

    PubMed

    Liu, Wanshuang; Zhao, Chenyang; Zhou, Rui; Zhou, Dan; Liu, Zhaolin; Lu, Xuehong

    2015-06-01

    In this article, alkali lignin (AL)-assisted direct exfoliation of MoS2 mineral into single-layer and few-layer nanosheets in water is reported for the first time. Under optimized conditions, the concentration of MoS2 nanosheets in the obtained dispersion can be as high as 1.75 ± 0.08 mg mL(-1), which is much higher than the typical reported concentrations (<1.0 mg mL(-1)) using synthetic polymers or compounds as surfactants. The stabilizing mechanism primarily lies in the electrostatic repulsion between negative charged AL, as suggested by zeta-potential measurements. When the exfoliated MoS2 nanosheets are applied as electrode materials for lithium ion batteries, they show much improved electrochemical performance compared with the pristine MoS2 mineral because of the enhanced ion and electron transfer kinetics. This facile, scalable and eco-friendly aqueous-based process in combination with renewable and ultra-low-cost lignin opens up possibilities for large-scale fabrication of MoS2-based nanocomposites and devices. Moreover, herein we demonstrate that AL is also an excellent surfactant for exfoliation of many other types of layered materials, including graphene, tungsten disulfide and boron nitride, in water, providing rich opportunities for a wider range of applications. PMID:25970569

  5. Exfoliated Egyptian kaolin immobilized heteropolyoxotungstate nanocomposite as an innovative antischistosomal agent: In vivo and in vitro bioactive studies.

    PubMed

    Bayaumy, Fatma E A; Darwish, Atef S

    2016-02-01

    This study aims to manipulate an antischistosomal nanocomposite based on exfoliated clay immobilized heteropolyoxotungstate. The nanocomposite's physicochemical characteristics were examined using XRD, Raman spectroscopy, FTIR, DLS, SEM, HR-TEM and AFM. Nano-sized spheroidal negatively charged Keggin-type heteropolyoxotungstate particles were developed along and between the exfoliated clay layers. The impact of the nanocomposite on Schistosoma mansoni-infected mice was studied through parasitological, physiological and histological analyses. Infected mice were orally vaccinated by a single nanocomposite dose (15mg/kg/day) for two weeks. The schistosomicidal activities of the nanocomposite in vitro were investigated by examining its dose- and time-dependent responses in terms of % worm mortality. The time-dependent morphological alterations in schistosomes at a nanocomposite dosage of 15μg/mL were followed by SEM. The nanocomposite exhibited potential schistosomicidal properties with a marked reduction in worm burden (~85% mortality), extensive deformities in the adult worm tegument and suckers, improvement of serum biochemical activities, and diminishment in granulomatous lesions. The in vitro release of heteropolyoxotungstate from exfoliated clay indicates the clay's ability to embrace the heteropolytungstate until its liberation at the parasitic districts. PMID:26652426

  6. Graphene via sonication assisted liquid-phase exfoliation.

    PubMed

    Ciesielski, Artur; Samorì, Paolo

    2014-01-01

    Graphene, the 2D form of carbon based material existing as a single layer of atoms arranged in a honeycomb lattice, has set the science and technology sectors alight with interest in the last decade in view of its astounding electrical and thermal properties, combined with its mechanical stiffness, strength and elasticity. Two distinct strategies have been undertaken for graphene production, i.e. the bottom-up and the top-down. The former relies on the generation of graphene from suitably designed molecular building blocks undergoing chemical reaction to form covalently linked 2D networks. The latter occurs via exfoliation of graphite into graphene. Bottom-up techniques, based on the organic syntheses starting from small molecular modules, when performed in liquid media, are both size limited, because macromolecules become more and more insoluble with increasing size, and suffer from the occurrence of side reactions with increasing molecular weight. Because of these reasons such a synthesis has been performed more and more on a solid (ideally catalytically active) surface. Substrate-based growth of single layers can be done also by chemical vapor deposition (CVD) or via reduction of silicon carbide, which unfortunately relies on the ability to follow a narrow thermodynamic path. Top-down approaches can be accomplished under different environmental conditions. Alongside the mechanical cleavage based on the scotch tape approach, liquid-phase exfoliation (LPE) methods are becoming more and more interesting because they are extremely versatile, potentially up-scalable, and can be used to deposit graphene in a variety of environments and on different substrates not available using mechanical cleavage or growth methods. Interestingly, LPE can be applied to produce different layered systems exhibiting different compositions such as BN, MoS2, WS2, NbSe2, and TaS2, thereby enabling the tuning of numerous physico-chemical properties of the material. Furthermore, LPE can be

  7. Botulinum Toxin and Muscle Atrophy: A Wanted or Unwanted Effect.

    PubMed

    Durand, Paul D; Couto, Rafael A; Isakov, Raymond; Yoo, Donald B; Azizzadeh, Babak; Guyuron, Bahman; Zins, James E

    2016-04-01

    While the facial rejuvenating effect of botulinum toxin type A is well known and widespread, its use in body and facial contouring is less common. We first describe its use for deliberate muscle volume reduction, and then document instances of unanticipated and undesirable muscle atrophy. Finally, we investigate the potential long-term adverse effects of botulinum toxin-induced muscle atrophy. Although the use of botulinum toxin type A in the cosmetic patient has been extensively studied, there are several questions yet to be addressed. Does prolonged botulinum toxin treatment increase its duration of action? What is the mechanism of muscle atrophy and what is the cause of its reversibility once treatment has stopped? We proceed to examine how prolonged chemodenervation with botulinum toxin can increase its duration of effect and potentially contribute to muscle atrophy. Instances of inadvertent botulinum toxin-induced atrophy are also described. These include the "hourglass deformity" secondary to botulinum toxin type A treatment for migraine headaches, and a patient with atrophy of multiple facial muscles from injections for hemifacial spasm. Numerous reports demonstrate that muscle atrophy after botulinum toxin type A treatment occurs and is both reversible and temporary, with current literature supporting the notion that repeated chemodenervation with botulinum toxin likely responsible for both therapeutic and incidental temporary muscle atrophy. Furthermore, duration of response may be increased with subsequent treatments, thus minimizing frequency of reinjection. Practitioners should be aware of the temporary and reversible effect of botulinum toxin-induced muscle atrophy and be prepared to reassure patients on this matter. PMID:26780946

  8. Emerging types of Shiga toxin-producing E. coli (STEC) O178 present in cattle, deer, and humans from Argentina and Germany

    PubMed Central

    Miko, Angelika; Rivas, Marta; Bentancor, Adriana; Delannoy, Sabine; Fach, Patrick; Beutin, Lothar

    2014-01-01

    More than 400 serotypes of Shiga toxin-producing Escherichia coli (STEC) have been implicated in outbreaks and sporadic human diseases. In recent years STEC strains belonging to serogroup O178 have been commonly isolated from cattle and food of bovine origin in South America and Europe. In order to explore the significance of these STEC strains as potential human pathogens, 74 German and Argentinean E. coli O178 strains from animals, food and humans were characterized phenotypically and investigated for their serotypes, stx-genotypes and 43 virulence-associated markers by a real-time PCR-microarray. The majority (n = 66) of the O178 strains belonged to serotype O178:H19. The remaining strains divided into O178:H7 (n = 6), O178:H10 (n = 1), and O178:H16 (n = 1). STEC O178:H19 strains were mainly isolated from cattle and food of bovine origin, but one strain was from a patient with hemolytic uremic syndrome (HUS). Genotyping of the STEC O178:H19 strains by pulsed-field gel electrophoresis revealed two major clusters of genetically highly related strains which differ in their stx-genotypes and non-Stx putative virulence traits, including adhesins, toxins, and serine-proteases. Cluster A-strains including the HUS-strain (n = 35) carried genes associated with severe disease in humans (stx2a, stx2d, ehxA, saa, subAB1, lpfAO113, terE combined with stx1a, espP, iha). Cluster B-strains (n = 26) showed a limited repertoire of virulence genes (stx2c, pagC, lpfAO113, espP, iha). Among O178:H7 strains isolated from deer meat and patients with uncomplicated disease a new STEC variant was detected that is associated with the genotype stx1c/stx2b/ehxA/subAB2/espI/[terE]/espP/iha. None of the STEC O178 strains was positive for locus of enterocyte effacement (LEE)- and nle-genes. Results indicate that STEC O178:H19 strains belong to the growing group of LEE-negative STEC that should be considered with respect to their potential to cause diseases in humans. PMID:24987616

  9. Tracing the metabolism of HT-2 toxin and T-2 toxin in barley by isotope-assisted untargeted screening and quantitative LC-HRMS analysis.

    PubMed

    Meng-Reiterer, Jacqueline; Varga, Elisabeth; Nathanail, Alexis V; Bueschl, Christoph; Rechthaler, Justyna; McCormick, Susan P; Michlmayr, Herbert; Malachová, Alexandra; Fruhmann, Philipp; Adam, Gerhard; Berthiller, Franz; Lemmens, Marc; Schuhmacher, Rainer

    2015-10-01

    An extensive study of the metabolism of the type A trichothecene mycotoxins HT-2 toxin and T-2 toxin in barley using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) is reported. A recently developed untargeted approach based on stable isotopic labelling, LC-Orbitrap-MS analysis with fast polarity switching and data processing by MetExtract software was combined with targeted LC-Q-TOF-MS(/MS) analysis for metabolite structure elucidation and quantification. In total, 9 HT-2 toxin and 13 T-2 toxin metabolites plus tentative isomers were detected, which were successfully annotated by calculation of elemental formulas and further LC-HRMS/MS measurements as well as partly identified with authentic standards. As a result, glucosylated forms of the toxins, malonylglucosides, and acetyl and feruloyl conjugates were elucidated. Additionally, time courses of metabolite formation and mass balances were established. For absolute quantification of those compounds for which standards were available, the method was validated by determining apparent recovery, signal suppression, or enhancement and extraction recovery. Most importantly, T-2 toxin was rapidly metabolised to HT-2 toxin and for both parent toxins HT-2 toxin-3-O-β-glucoside was identified (confirmed by authentic standard) as the main metabolite, which reached its maximum already 1 day after toxin treatment. Graphical Abstract Isotope-assisted untargeted screening of HT-2 toxin and T-2 toxin metabolites in barley. PMID:26335000

  10. Naturally Occurring Food Toxins

    PubMed Central

    Dolan, Laurie C.; Matulka, Ray A.; Burdock, George A.

    2010-01-01

    Although many foods contain toxins as a naturally-occurring constituent or, are formed as the result of handling or processing, the incidence of adverse reactions to food is relatively low. The low incidence of adverse effects is the result of some pragmatic solutions by the US Food and Drug Administration (FDA) and other regulatory agencies through the creative use of specifications, action levels, tolerances, warning labels and prohibitions. Manufacturers have also played a role by setting limits on certain substances and developing mitigation procedures for process-induced toxins. Regardless of measures taken by regulators and food producers to protect consumers from natural food toxins, consumption of small levels of these materials is unavoidable. Although the risk for toxicity due to consumption of food toxins is fairly low, there is always the possibility of toxicity due to contamination, overconsumption, allergy or an unpredictable idiosyncratic response. The purpose of this review is to provide a toxicological and regulatory overview of some of the toxins present in some commonly consumed foods, and where possible, discuss the steps that have been taken to reduce consumer exposure, many of which are possible because of the unique process of food regulation in the United States. PMID:22069686

  11. [Toxins of Clostridium perfringens as a natural and bioterroristic threats].

    PubMed

    Omernik, Andrzej; Płusa, Tadeusz

    2015-09-01

    Clostridium perfringens is absolutely anaerobic rod-shaped, sporeforming bacterium. The morbidity is connected with producing toxins. Depending on the type of toxin produced Clostridium perfringens can be divided into five serotypes:A-E. Under natural conditions, this bacterium is responsible for local outbreaks of food poisoning associated with eating contaminated food which which was improperly heat treated. Some countries with lower economic level are endemic foci of necrotizing enteritis caused by Clostridium perfringens. The bacterium is also a major cause of gas gangrene. It is a disease, associated with wound infection, with potentially fatal prognosis in the case of treatment's delays. In the absence of early radical surgery, antibiotic therapy and (if available) hyperbaric treatment leads to the spread of toxins in the body causing shock, coma and death. Due to the force of produced toxins is a pathogen that poses a substrate for the production of biological weapons. It could potentially be used to induce outbreaks of food poisoning and by missiles contamination by spore lead to increased morbidity of gas gangrene in injured soldiers. C. perfringens types B and D produce epsilon toxin considered to be the third most powerful bacterial toxin. Because of the ability to disperse the toxin as an aerosol and a lack of methods of treatment and prevention of poisoning possible factors it is a potential tool for bioterrorism It is advisable to continue research into vaccines and treatments for poisoning toxins of C. perfringens. PMID:26449576

  12. Organic salt-assisted liquid-phase exfoliation of graphite to produce high-quality graphene

    NASA Astrophysics Data System (ADS)

    Du, Wencheng; Lu, Jie; Sun, Peipei; Zhu, Yinyan; Jiang, Xiaoqing

    2013-05-01

    Certain ordinary organic salts, such as edetate disodium, sodium tartrate, potassium sodium tartrate and sodium citrate were found to have universal and efficient assistant effect for liquid-phase exfoliation of graphite in common organic solvents to produce pristine graphene. Up to 123 times enhanced exfoliation efficiency was observed when sodium citrate was introduced into an exfoliation system consisting of natural graphite powder and dimethyl sulfoxide. TEM, AFM, Raman spectroscopy, EDX, TGA, and FTIR analysis showed graphite was successfully exfoliated into single or few-layer graphene nanosheets which were free of defects and oxides. The method is simple, effective, safe and economical.

  13. Electrical Characterization of Graphene Flakes Synthesized Using Liquid Phase Exfoliation of Graphite in Isopropyl Alcohol

    NASA Astrophysics Data System (ADS)

    Talapatra, Saikat; Muchharla, Baleeswaraiah; Connolly, Mitchell; Winchester, Andrew; Ghosh, Sujoy; Kar, Swastik; Southern Illinois University Carbondale Team; Northeastern University, Boston Collaboration

    2013-03-01

    Liquid-phase exfoliation processes for synthesis of nano structures is often a simpler route to get functional nanomaterials in large scale. Here we will report on the synthesis of graphene flakes using exfoliation of bulk graphite in isopropyl alcohol. We will also present electrical characterization of thin film devices made from these exfoliated flakes. Temperature dependence of resistance performed for 10K exfoliated flakes under electrochemical gating environment will be presented and discussed.

  14. Use of botulinum toxin in Meige's disease.

    PubMed

    Maurri, S; Brogelli, S; Alfieri, G; Barontini, F

    1988-01-01

    Four patients with severe Meige's disease (blepharospasm-oromandibular dystonia) have been treated, after having given an informed consent, by local injections of purified botulinum toxin type "A". Previous systemic therapy with anticholinergics, dopamine antagonists and other drugs had been unsuccessful in all these subjects. Each patient was treated by saline solution injected with the same method as botulinum toxin, just once. The self-evaluation of patients and the clinical evaluation that some of us- unaware of the kind of therapy which had been performed- gave to the symptoms on the basis of videotapes, for each session of injection, showed that the injections of botulinum toxin are effective in the treatment of such disorder. The duration of the beneficial effect was slightly shorter in these patients than in patients with blepharospasm treated by the same method. PMID:3247565

  15. [Toxins as a biological weapon].

    PubMed

    Płusa, Tadeusz

    2015-09-01

    The criteria for recognizing a chemical compound for the toxin are vague and gave it the possibility of inclusion in this group a number of biological agents. Toxins list is extensive, but the interest is focused on bacterial toxins, poisons derived from snake venoms, algae and plant proteins, and small molecules. Particular attention is focused on the so-called "sea" toxins, which include tetrodotoxin, brevetoxin and saxitoxin. This indicates the search for a new hitherto unknown potential bioterrorist threats. PMID:26449572

  16. Botulinum Toxin in Neurogenic Detrusor Overactivity

    PubMed Central

    Ferreira, Rúiter Silva; Rassi, Mauricio Carneiro

    2012-01-01

    Purpose To evaluate the effects of botulinum toxin on urodynamic parameters and quality of life in patients with neurogenic detrusor overactivity. Methods Thirty four adult patients with spinal cord injury and detrusor overactivity were selected. The patients received 300 units of botulinum toxin type A. The endpoints evaluated with the episodes of urinary incontinence and measured the maximum cystometric capacity, maximum amplitude of detrusor pressure and bladder compliance at the beginning and end of the study (24 weeks) and evaluated the quality of life by applying the Qualiveen questionnaire. Results A significant decrease in the episodes of urinary incontinence was observed. All urodynamic parameters presented a significant improvement. The same was observed in the quality of life index and the specific impact of urinary problems scores from the Qualiveen questionnaire. Six patients did not complete the study, two due to incomplete follow-up, and four violated protocol and were excluded from the analyses. No systemic adverse events of botulinum toxin type A were reported. Conclusions A botulinum toxin type A showed a significantly improved response in urodynamics parameters and specific and general quality of life. PMID:23094220

  17. Biomolecule-assisted exfoliation and dispersion of graphene and other two-dimensional materials: a review of recent progress and applications.

    PubMed

    Paredes, J I; Villar-Rodil, S

    2016-08-25

    Direct liquid-phase exfoliation of layered materials by means of ultrasound, shear forces or electrochemical intercalation holds enormous promise as a convenient, cost-effective approach to the mass production of two-dimensional (2D) materials, particularly in the form of colloidal suspensions of high quality and micrometer- and submicrometer-sized flakes. Of special relevance due to environmental and practical reasons is the production of 2D materials in aqueous medium, which generally requires the use of certain additives (surfactants and other types of dispersants) to assist in the exfoliation and colloidal stabilization processes. In this context, biomolecules have received, in recent years, increasing attention as dispersants for 2D materials, as they provide a number of advantages over more conventional, synthetic surfactants. Here, we review research progress in the use of biomolecules as exfoliating and dispersing agents for the production of 2D materials. Although most efforts in this area have focused on graphene, significant advances have also been reported with transition metal dichalcogenides (MoS2, WS2, etc.) or hexagonal boron nitride. Particular emphasis is placed on the specific merits of different types of biomolecules, including proteins and peptides, nucleotides and nucleic acids (RNA, DNA), polysaccharides, plant extracts and bile salts, on their role as efficient colloidal dispersants of 2D materials, as well as on the potential applications that have been explored for such biomolecule-exfoliated materials. These applications are wide-ranging and encompass the fields of biomedicine (photothermal and photodynamic therapy, bioimaging, biosensing, etc.), energy storage (Li- and Na-ion batteries), catalysis (e.g., catalyst supports for the oxygen reduction reaction or electrocatalysts for the hydrogen evolution reaction), or composite materials. As an incipient area of research, a number of knowledge gaps, unresolved issues and novel future

  18. Toxin plasmids of Clostridium perfringens.

    PubMed

    Li, Jihong; Adams, Vicki; Bannam, Trudi L; Miyamoto, Kazuaki; Garcia, Jorge P; Uzal, Francisco A; Rood, Julian I; McClane, Bruce A

    2013-06-01

    In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  19. ICESluvan, a 94-Kilobase Mosaic Integrative Conjugative Element Conferring Interspecies Transfer of VanB-Type Glycopeptide Resistance, a Novel Bacitracin Resistance Locus, and a Toxin-Antitoxin Stabilization System

    PubMed Central

    Bjørkeng, Eva K.; Hjerde, Erik; Pedersen, Torunn; Sundsfjord, Arnfinn

    2013-01-01

    A 94-kb integrative conjugative element (ICESluvan) transferable to Enterococcus faecium and Enterococcus faecalis from an animal isolate of Streptococcus lutetiensis consists of a mosaic of genetic fragments from different Gram-positive bacteria. A variant of ICESluvan was confirmed in S. lutetiensis from a patient. A complete Tn5382/Tn1549 with a vanB2 operon is integrated into a streptococcal ICESde3396-like region harboring a putative bacteriophage exclusion system, a putative agglutinin receptor precursor, and key components of a type IV secretion system. Moreover, ICESluvan encodes a putative MobC family mobilization protein and a relaxase and, thus, in total has all genetic components essential for conjugative transfer. A 9-kb element within Tn5382/Tn1549 encodes, among others, putative proteins similar to the TnpX site-specific recombinase in Faecalibacterium and VanZ in Paenibacillus, which may contribute to the detected low-level teicoplanin resistance. Furthermore, ICESluvan encodes a novel bacitracin resistance locus that is associated with reduced susceptibility to bacitracin when transferred to E. faecium. The expression of a streptococcal pezAT toxin-antitoxin-encoding operon of ICESluvan in S. lutetiensis, E. faecium, and E. faecalis was confirmed by reverse transcription (RT)-PCR, indicating an active toxin-antitoxin system which may contribute to stabilizing ICESluvan within new hosts. Junction PCR and DNA sequencing confirmed that ICESluvan excised to form a circular intermediate in S. lutetiensis, E. faecalis, and E. faecium. Transfer between E. faecalis cells was observed in the presence of helper plasmid pIP964. Sequence analysis of the original S. lutetiensis donor and enterococcal transconjugants showed that ICESluvan integrates in a site-specific manner into the C-terminal end of the chromosomal tRNA methyltransferase gene rumA. PMID:24078615

  20. Staphylococcus aureus Alpha-Toxin Mediates General and Cell Type-Specific Changes in Metabolite Concentrations of Immortalized Human Airway Epithelial Cells

    PubMed Central

    Gierok, Philipp; Harms, Manuela; Richter, Erik; Hildebrandt, Jan-Peter; Lalk, Michael; Mostertz, Jörg; Hochgräfe, Falko

    2014-01-01

    Staphylococcus aureus alpha-toxin (Hla) is a potent pore-forming cytotoxin that plays an important role in the pathogenesis of S. aureus infections, including pneumonia. The impact of Hla on the dynamics of the metabolome in eukaryotic host cells has not been investigated comprehensively. Using 1H-NMR, GC-MS and HPLC-MS, we quantified the concentrations of 51 intracellular metabolites and assessed alterations in the amount of 25 extracellular metabolites in the two human bronchial epithelial cell lines S9 and 16HBE14o− under standard culture conditions and after treatment with sub-lethal amounts (2 µg/ml) of recombinant Hla (rHla) in a time-dependent manner. Treatment of cells with rHla caused substantial decreases in the concentrations of intracellular metabolites from different metabolic pathways in both cell lines, including ATP and amino acids. Concomitant increases in the extracellular concentrations were detected for various intracellular compounds, including nucleotides, glutathione disulfide and NAD+. Our results indicate that rHla has a major impact on the metabolome of eukaryotic cells as a consequence of direct rHla-mediated alterations in plasma membrane permeability or indirect effects mediated by cellular signalling. However, cell-specific changes also were observed. Glucose consumption and lactate production rates suggest that the glycolytic activity of S9 cells, but not of 16HBE14o− cells, is increased in response to rHla. This could contribute to the observed higher level of resistance of S9 cells against rHla-induced membrane damage. PMID:24733556

  1. Evolution of a self-inducible cytolethal distending toxin type V-encoding bacteriophage from Escherichia coli O157:H7 to Shigella sonnei.

    PubMed

    Allué-Guardia, Anna; Imamovic, Lejla; Muniesa, Maite

    2013-12-01

    Some cdt genes are located within the genome of inducible or cryptic bacteriophages, but there is little information about the mechanisms of cdt transfer because of the reduced number of inducible Cdt phages described. In this study, a new self-inducible Myoviridae Cdt phage (ΦAA91) was isolated from a nonclinical O157:H7 Shiga toxin-producing Escherichia coli strain and was used to lysogenize a cdt-negative strain of Shigella sonnei. We found that the phage induced from S. sonnei (ΦAA91-ss) was not identical to the original phage. ΦAA91-ss was used to infect a collection of 57 bacterial strains, was infectious in 59.6% of the strains, and was able to lysogenize 22.8% of them. The complete sequence of ΦAA91-ss showed a 33,628-bp genome with characteristics of a P2-like phage with the cdt operon located near the cosR site. We found an IS21 element composed of two open reading frames inserted within the cox gene of the phage, causing gene truncation. Truncation of cox does not affect lytic induction but could contribute to phage recombination and generation of lysogens. The IS21 element was not present in the ΦAA91 phage from E. coli, but it was incorporated into the phage genome after its transduction in Shigella. This study shows empirically the evolution of temperate bacteriophages carrying virulence genes after infecting a new host and the generation of a phage population with better lysogenic abilities that would ultimately lead to the emergence of new pathogenic strains. PMID:24109226

  2. Controlling exfoliation in order to minimize damage during dispersion of long SWCNTs for advanced composites

    PubMed Central

    Yoon, Howon; Yamashita, Motoi; Ata, Seisuke; Futaba, Don N.; Yamada, Takeo; Hata, Kenji

    2014-01-01

    We propose an approach to disperse long single-wall carbon nanotubes (SWCNTs) in a manner that is most suitable for the fabrication of high-performance composites. We compare three general classes of dispersion mechanisms, which encompass 11 different dispersion methods, and we have dispersed long SWCNTs, short multi-wall carbon nanotubes, and short SWCNTs in order to understand the most appropriate dispersion methods for the different types of CNTs. From this study, we have found that the turbulent flow methods, as represented by the Nanomizer and high-pressure jet mill methods, produced unique and superior dispersibility of long SWCNTs, which was advantageous for the fabrication of highly conductive composites. The results were interpreted to imply that the biaxial shearing force caused an exfoliation effect to disperse the long SWCNTs homogeneously while suppressing damage. A conceptual model was developed to explain this dispersion mechanism, which is important for future work on advanced CNT composites. PMID:24469607

  3. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering

    PubMed Central

    Rosa, Vinicius; Dubey, Nileshkumar; Islam, Intekhab; Min, Kyung-San; Nör, Jacques E.

    2016-01-01

    Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates). The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies. PMID:27313627

  4. Pluripotency of Stem Cells from Human Exfoliated Deciduous Teeth for Tissue Engineering.

    PubMed

    Rosa, Vinicius; Dubey, Nileshkumar; Islam, Intekhab; Min, Kyung-San; Nör, Jacques E

    2016-01-01

    Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative pluripotent cells that can be retrieved from primary teeth. Although SHED are isolated from the dental pulp, their differentiation potential is not limited to odontoblasts only. In fact, SHED can differentiate into several cell types including neurons, osteoblasts, adipocytes, and endothelial cells. The high plasticity makes SHED an interesting stem cell model for research in several biomedical areas. This review will discuss key findings about the characterization and differentiation of SHED into odontoblasts, neurons, and hormone secreting cells (e.g., hepatocytes and islet-like cell aggregates). The outcomes of the studies presented here support the multipotency of SHED and their potential to be used for tissue engineering-based therapies. PMID:27313627

  5. Cell exfoliation, separation, and concentration in the field of a standing ultrasonic wave

    NASA Astrophysics Data System (ADS)

    Pashovkin, T. N.; Sadikova, D. G.

    2009-10-01

    We present theoretical and experimental results on the study of forces acting on cells in suspensions in the field of a standing ultrasonic wave (by the example of rat and guinea-pig erythrocytes, yeast, and chlorella) and leading to cell and liquid phase exfoliation, cell separation into fractions, and cell concentration in variable-pressure nodes. The experimental results are presented as plots in the coordinates of the average density of the energy of the ultrasonic field and the linear velocity of the flow of the cell suspension. Straight lines in the plots separate the regions of cell concentration, separation, and washout. The slope of these straight lines is a characteristic of a certain cell type. Agreement of the experimental and theoretically predicted data is shown.

  6. The trabecular meshwork in normal eyes and in exfoliation glaucoma.

    PubMed

    Rasmussen, Carol A; Kaufman, Paul L

    2014-01-01

    Trabecular meshwork (TM) and ciliary muscle contraction and relaxation function together to provide control of outflow. The active role the TM plays in the regulation of intraocular pressure (IOP) is mediated by cytoskeletal and contractility mechanisms as well as signal/transduction factors that mediate its response to stressors. This complex system is altered with age and the glaucomas, and it can be difficult to differentiate between the various etiological effects/agents. Factors such as a compromised antioxidant defense system and altered extracellular matrix metabolism are known to contribute to impaired outflow and may be common to primary open-angle glaucoma, exfoliation syndrome, and exfoliation glaucoma (XFG). Genes differentially expressed in diseased ocular tissue or in cultured HTM cell models, and thus implicated in the disease process, include SOD2, ALDH1A1, MGST1, LOX, and LOXL1, elements of the transforming growth factor-β/bone morphogenetic protein/SMAD signaling pathways, connective tissue growth factor, matrix metalloproteinase-2, a tissue inhibitor of metalloproteinases also known as TIMP-2, and endothelin-1 (ET-1). In exfoliation syndrome and XFG fibrillar, proteinaceous extracellular material is produced in excess and accumulates in both outflow pathways but does not always lead to elevated IOP. Locally produced material may accumulate in the intertrabecular spaces, juxtacanalicular (JCT) meshwork, and the inner wall of Schlemm's canal as a result of a combination of both excessive synthesis and insufficient degradation. An increase in JCT plaque and decreased cellularity in the TM are thought to contribute to decreased outflow facility in glaucoma patients, but XFG patient specimens show reduced extracellular plaque material in the JCT, and the structural integrity of trabecular endothelial cells is mostly retained and cellularity remains unchanged. The distinctions between causes/effects of structural changes leading to reduced outflow

  7. Chemical delithiation and exfoliation of LixCoO2

    NASA Astrophysics Data System (ADS)

    Basch, Angelika; de Campo, Liliana; Albering, Jörg H.; White, John W.

    2014-12-01

    Progressive chemical .delithiation of commercially available lithium cobalt oxide (LiCoO2) showed consecutive changes in the crystal properties. Rietveld refinement of high resolution X-ray and neutron diffraction revealed an increased lattice parameter c and a reduced lattice parameter a for chemically delithiated samples. Using electron microscopy we have also followed the changes in the texture of the samples towards what we have found is a critical layer stoichiometry of about LixCoO2 with x=1/3 that causes the grains to exfoliate. The pattern of etches by delithiation suggests that unrelieved strain fields may produce chemical activity.

  8. Chemical delithiation and exfoliation of LixCoO2

    PubMed Central

    Basch, Angelika; de Campo, Liliana; Albering, Jörg H.; White, John W.

    2014-01-01

    Progressive chemical .delithiation of commercially available lithium cobalt oxide (LiCoO2) showed consecutive changes in the crystal properties. Rietveld refinement of high resolution X-ray and neutron diffraction revealed an increased lattice parameter c and a reduced lattice parameter a for chemically delithiated samples. Using electron microscopy we have also followed the changes in the texture of the samples towards what we have found is a critical layer stoichiometry of about LixCoO2 with x=1/3 that causes the grains to exfoliate. The pattern of etches by delithiation suggests that unrelieved strain fields may produce chemical activity. PMID:25473127

  9. Stable Aqueous Dispersion of Exfoliated Graphene for Tribological Applications.

    PubMed

    Liang, Shuaishuai; Shen, Zhigang; Yi, Min; Liu, Lei; Cai, Chujiang; Zhang, Xiaojing; Ma, Shulin

    2016-02-01

    In this study, the directly exfoliated graphene prepared by a jet cavitation method was tested as additive in pure water toward tribological applications. Reductions of friction coefficient and wear volume up to 22.8% and 44.4% respectively were achieved by addition of the graphene flakes. The as-prepared aqueous graphene dispersions exhibited high stability against sedimentation, and concurrently maintained their tribological properties after deposited for 15 days. The improvement in lubricating and anti-wear performances can be attributed to the graphene network formed on the sliding surfaces during the test. PMID:27433609

  10. Structural Insights into Bacillus thuringiensis Cry, Cyt and Parasporin Toxins

    PubMed Central

    Xu, Chengchen; Wang, Bi-Cheng; Yu, Ziniu; Sun, Ming

    2014-01-01

    Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively. PMID:25229189

  11. Transfer of Select Agents and Toxins: 2003-2013.

    PubMed

    Shelby, Bryan D; Cartagena, Debora; McClee, Vondguraus; Gangadharan, Denise; Weyant, Robbin

    2015-01-01

    The Federal Select Agent Program, which is composed of the Centers for Disease Control and Prevention Division of Select Agents and Toxins and the Animal and Plant Health Inspection Service Agricultural Select Agent Services, regulates entities that possess, use, or transfer biological select agents and toxins in the United States and must preapprove all transfers within or into the US. The requirement to preapprove transfers allows the Federal Select Agent Program to monitor and track shipments to receive alerts of theft, loss, or release during shipment, thereby protecting public health and safety. As part of the program, the Division of Select Agents and Toxins regulates biological select agents and toxins that have been identified by the US government as posing a severe threat to public health and safety. The division analyzed 4,402 transfers that occurred between March 2003 and December 2013 to identify frequently transferred biological select agents and toxins and the types of entities involved in transfers. During the study period, 1 package was lost during shipment and it was determined not to pose a threat to public health. The Federal Bureau of Investigation investigated the loss and concluded that the package was most likely damaged by the commercial carrier and discarded. Further, there were no reports of theft or release associated with biological select agents and toxins shipments. This report represents the first in-depth review of biological select agent and toxin transfers that were approved by the Division of Select Agents and Toxins. PMID:26186667

  12. CYANOBACTERIA AND THEIR TOXINS.

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  13. CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  14. Toxin-induced respiratory distress.

    PubMed

    McKay, Charles A

    2014-02-01

    This article describes the impact of various toxic substances on the airway and pulmonary system. Pulmonary anatomy and physiology provide the basis for understanding the response to toxin-induced injury. Simple asphyxiants displace oxygen from the inspired air. Respiratory irritants include water-soluble and water-insoluble compounds. Several inhaled agents produce direct airway injury, which may be mediated by caustic, thermal, and hydrocarbon exposures. Unique pulmonary toxins and toxicants are discussed, as well as inhaled toxin mixtures. Several inhaled toxins may also impair oxygen transport. The pulmonary system may also provide a mechanism for systemic toxin delivery on respiratory exposure. PMID:24275172

  15. [Protein toxins of Staphylococcus aureus].

    PubMed

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented. PMID:25051707

  16. STEAM-SIDE OXIDE SCALE EXFOLIATION BEHAVIOR IN SUPERHEATERS AND REHEATERS

    SciTech Connect

    Sabau, Adrian S; Shingledecker, John P.; Wright, Ian G

    2011-01-01

    Advances in materials for power plants include not only new materials with higher-temperature capabilities, but also the use of current materials at increasingly higher temperatures. This latter activity builds on extensive experience of the performance of the various alloys, and provides a basis for identifying changes in alloy behavior with increasing temperature as well as understanding the factors that ultimately determine the maximum use temperatures of the different alloy classes. This paper presents results from an effort to model the exfoliation processes of steam-side oxide scales in a manner that describes as accurately as possible the evolution of strains in oxides growing inside small-diameter tubes subjected to large thermal gradients and to thermal transients typical of normal steam boiler operation. One way of portraying the results of such calculations is by plotting the evolving strains in a given oxide scale on an Exfoliation Diagram (of the type pioneered by Manning et al. of the British Central Electricity Research Laboratory) to determine the earliest time at which the trajectory of these strains intersects a criterion for scale failure. Understanding of how such strain trajectories differ among different alloys and are affected by the major variables associated with boiler operation has the potential to suggest boiler operating strategies to manage scale exfoliation, as well as to highlight the mode of scale failure and the limitations of each alloy. Preliminary results are presented of the strain trajectories calculated for alloys T22, T91, and TP347 subjected to the conditions experienced by superheaters under assumed boiler operating scenarios. For all three alloys the earliest predicted scale failures were associated with the increased strains developed during a boiler shut-down event; indeed, in the cases considered it appeared unlikely that scale failure would occur in any practically meaningful time due to strains accumulated during

  17. Clostridium perfringens epsilon toxin: the third most potent bacterial toxin known.

    PubMed

    Alves, Guilherme Guerra; Machado de Ávila, Ricardo Andrez; Chávez-Olórtegui, Carlos Delfin; Lobato, Francisco Carlos Faria

    2014-12-01

    Epsilon toxin (ETX) is produced by Clostridium perfringens type B and D strains and causes enterotoxemia, a highly lethal disease with major impacts on the farming of domestic ruminants, particularly sheep. ETX belongs to the aerolysin-like pore-forming toxin family. Although ETX has striking similarities to other toxins in this family, ETX is often more potent, with an LD50 of 100 ng/kg in mice. Due to this high potency, ETX is considered as a potential bioterrorism agent and has been classified as a category B biological agent by the Centers for Disease Control and Prevention (CDC) of the United States. The protoxin is converted to an active toxin through proteolytic cleavage performed by specific proteases. ETX is absorbed and acts locally in the intestines then subsequently binds to and causes lesions in other organs, including the kidneys, lungs and brain. The importance of this toxin for veterinary medicine and its possible use as a biological weapon have drawn the attention of researchers and have led to a large number of studies investigating ETX. The aim of the present work is to review the existing knowledge on ETX from C. perfringens type B and D. PMID:25234332

  18. Characterization of two different toxins of Wickerhamomyces anomalus (Pichia anomala) VKM Y-159.

    PubMed

    Farkas, Z; Márki-Zay, J; Kucsera, Judit; Vágvölgyi, Cs; Golubev, W I; Pfeiffer, Ilona

    2012-06-01

    Wickerhamomyces anomalus VKM Y-159 strain produces two types of toxin designated as WAKT a and WAKT b, encoded by chromosomal genes. The WAKT a toxin is heat-labile, pronase sensitive acting in pH range 3-4 affecting on several yeasts including pathogenic Candida species while the WAKT b toxin is protease- and thermo-resistant, acting in pH range 3-7 on two species, Candida alai and Candida norvegica. The rapid decrease of the number of viable cells after toxin treatment demonstrates that both toxins have cytocidic effect. PMID:22695525

  19. Wake me when it's over - Bacterial toxin-antitoxin proteins and induced dormancy.

    PubMed

    Coussens, Nathan P; Daines, Dayle A

    2016-06-01

    Toxin-antitoxin systems are encoded by bacteria and archaea to enable an immediate response to environmental stresses, including antibiotics and the host immune response. During normal conditions, the antitoxin components prevent toxins from interfering with metabolism and arresting growth; however, toxin activation enables microbes to remain dormant through unfavorable conditions that might continue over millions of years. Intense investigations have revealed a multitude of mechanisms for both regulation and activation of toxin-antitoxin systems, which are abundant in pathogenic microorganisms. This minireview provides an overview of the current knowledge regarding type II toxin-antitoxin systems along with their clinical and environmental implications. PMID:27216598

  20. Arrangement of the Clostridium baratii F7 Toxin Gene Cluster with Identification of a σ Factor That Recognizes the Botulinum Toxin Gene Cluster Promoters

    SciTech Connect

    Dover, Nir; Barash, Jason R.; Burke, Julianne N.; Hill, Karen K.; Detter, John C.; Arnon, Stephen S.

    2014-05-22

    Botulinum neurotoxin (BoNT) is the most poisonous substances known and its eight toxin types (A to H) are distinguished by the inability of polyclonal antibodies that neutralize one toxin type to neutralize any of the other seven toxin types. Infant botulism, an intestinal toxemia orphan disease, is the most common form of human botulism in the United States. It results from swallowed spores of Clostridium botulinum (or rarely, neurotoxigenic Clostridium butyricum or Clostridium baratii) that germinate and temporarily colonize the lumen of the large intestine, where, as vegetative cells, they produce botulinum toxin. Botulinum neurotoxin is encoded by the bont gene that is part of a toxin gene cluster that includes several accessory genes. In this paper, we sequenced for the first time the complete botulinum neurotoxin gene cluster of nonproteolytic C. baratii type F7. Like the type E and the nonproteolytic type F6 botulinum toxin gene clusters, the C. baratii type F7 had an orfX toxin gene cluster that lacked the regulatory botR gene which is found in proteolytic C. botulinum strains and codes for an alternative σ factor. In the absence of botR, we identified a putative alternative regulatory gene located upstream of the C. baratii type F7 toxin gene cluster. This putative regulatory gene codes for a predicted σ factor that contains DNA-binding-domain homologues to the DNA-binding domains both of BotR and of other members of the TcdR-related group 5 of the σ70 family that are involved in the regulation of toxin gene expression in clostridia. We showed that this TcdR-related protein in association with RNA polymerase core enzyme specifically binds to the C. baratii type F7 botulinum toxin gene cluster promoters. Finally, this TcdR-related protein may therefore be involved in regulating the expression of the genes of the botulinum toxin gene cluster in neurotoxigenic C. baratii.

  1. Arrangement of the Clostridium baratii F7 Toxin Gene Cluster with Identification of a σ Factor That Recognizes the Botulinum Toxin Gene Cluster Promoters

    PubMed Central

    Dover, Nir; Barash, Jason R.; Burke, Julianne N.; Hill, Karen K.; Detter, John C.; Arnon, Stephen S.

    2014-01-01

    Botulinum neurotoxin (BoNT) is the most poisonous substances known and its eight toxin types (A to H) are distinguished by the inability of polyclonal antibodies that neutralize one toxin type to neutralize any of the other seven toxin types. Infant botulism, an intestinal toxemia orphan disease, is the most common form of human botulism in the United States. It results from swallowed spores of Clostridium botulinum (or rarely, neurotoxigenic Clostridium butyricum or Clostridium baratii) that germinate and temporarily colonize the lumen of the large intestine, where, as vegetative cells, they produce botulinum toxin. Botulinum neurotoxin is encoded by the bont gene that is part of a toxin gene cluster that includes several accessory genes. We sequenced for the first time the complete botulinum neurotoxin gene cluster of nonproteolytic C. baratii type F7. Like the type E and the nonproteolytic type F6 botulinum toxin gene clusters, the C. baratii type F7 had an orfX toxin gene cluster that lacked the regulatory botR gene which is found in proteolytic C. botulinum strains and codes for an alternative σ factor. In the absence of botR, we identified a putative alternative regulatory gene located upstream of the C. baratii type F7 toxin gene cluster. This putative regulatory gene codes for a predicted σ factor that contains DNA-binding-domain homologues to the DNA-binding domains both of BotR and of other members of the TcdR-related group 5 of the σ70 family that are involved in the regulation of toxin gene expression in clostridia. We showed that this TcdR-related protein in association with RNA polymerase core enzyme specifically binds to the C. baratii type F7 botulinum toxin gene cluster promoters. This TcdR-related protein may therefore be involved in regulating the expression of the genes of the botulinum toxin gene cluster in neurotoxigenic C. baratii. PMID:24853378

  2. Graphene from electrochemical exfoliation and its direct applications in enhanced energy storage devices.

    PubMed

    Wei, Di; Grande, Lorenzo; Chundi, Vishnu; White, Richard; Bower, Chris; Andrew, Piers; Ryhänen, Tapani

    2012-01-30

    Graphite was electrochemically exfoliated in mixtures of room temperature ionic liquids and deionized water containing lithium salts to produce functionalized graphenes and such an electrochemical exfoliation technique can be directly used in making primary battery electrodes with significantly enhanced specific energy capacity. PMID:22170354

  3. Small Molecule-Assisted Exfoliation of Layered Zirconium Phosphate Nanoplatelets by Ionic Liquids.

    PubMed

    Xia, Fangqing; Yong, Huaisong; Han, Xiao; Sun, Dazhi

    2016-12-01

    Exfoliation of layered inorganic nanomaterials into single-layered sheets has been widely interested in materials chemistry and composite fabrication. Here, we report the exfoliation of layered zirconium phosphate nanoplatelets by using small molecule intercalating agents in ionic liquids, which opens a new platform for fabricating single-layered inorganic materials from synthetic layered compounds. PMID:27460596

  4. Small Molecule-Assisted Exfoliation of Layered Zirconium Phosphate Nanoplatelets by Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Xia, Fangqing; Yong, Huaisong; Han, Xiao; Sun, Dazhi

    2016-07-01

    Exfoliation of layered inorganic nanomaterials into single-layered sheets has been widely interested in materials chemistry and composite fabrication. Here, we report the exfoliation of layered zirconium phosphate nanoplatelets by using small molecule intercalating agents in ionic liquids, which opens a new platform for fabricating single-layered inorganic materials from synthetic layered compounds.

  5. Clostridium Perfringens Toxins Involved in Mammalian Veterinary Diseases.

    PubMed

    Uzal, F A; Vidal, J E; McClane, B A; Gurjar, A A

    2010-01-01

    Clostridium perfringens is a gram-positive anaerobic rod that is classified into 5 toxinotypes (A, B, C, D, and E) according to the production of 4 major toxins, namely alpha (CPA), beta (CPB), epsilon (ETX) and iota (ITX). However, this microorganism can produce up to 16 toxins in various combinations, including lethal toxins such as perfringolysin O (PFO), enterotoxin (CPE), and beta2 toxin (CPB2). Most diseases caused by this microorganism are mediated by one or more of these toxins. The role of CPA in intestinal disease of mammals is controversial and poorly documented, but there is no doubt that this toxin is essential in the production of gas gangrene of humans and several animal species. CPB produced by C. perfringens types B and C is responsible for necrotizing enteritis and enterotoxemia mainly in neonatal individuals of several animal species. ETX produced by C. perfringens type D is responsible for clinical signs and lesions of enterotoxemia, a predominantly neurological disease of sheep and goats. The role of ITX in disease of animals is poorly understood, although it is usually assumed that the pathogenesis of intestinal diseases produced by C. perfringens type E is mediated by this toxin. CPB2, a necrotizing and lethal toxin that can be produced by all types of C. perfringens, has been blamed for disease in many animal species, but little information is currently available to sustain or rule out this claim. CPE is an important virulence factor for C. perfringens type A gastrointestinal disease in humans and dogs; however, the data implicating CPE in other animal diseases remains ambiguous. PFO does not seem to play a direct role as the main virulence factor for animal diseases, but it may have a synergistic role with CPA-mediated gangrene and ETX-mediated enterotoxemia. The recent improvement of animal models for C. perfringens infection and the use of toxin gene knock-out mutants have demonstrated the specific pathogenic role of several toxins of C

  6. Clostridium Perfringens Toxins Involved in Mammalian Veterinary Diseases

    PubMed Central

    Uzal, F. A.; Vidal, J. E.; McClane, B. A.; Gurjar, A. A.

    2013-01-01

    Clostridium perfringens is a gram-positive anaerobic rod that is classified into 5 toxinotypes (A, B, C, D, and E) according to the production of 4 major toxins, namely alpha (CPA), beta (CPB), epsilon (ETX) and iota (ITX). However, this microorganism can produce up to 16 toxins in various combinations, including lethal toxins such as perfringolysin O (PFO), enterotoxin (CPE), and beta2 toxin (CPB2). Most diseases caused by this microorganism are mediated by one or more of these toxins. The role of CPA in intestinal disease of mammals is controversial and poorly documented, but there is no doubt that this toxin is essential in the production of gas gangrene of humans and several animal species. CPB produced by C. perfringens types B and C is responsible for necrotizing enteritis and enterotoxemia mainly in neonatal individuals of several animal species. ETX produced by C. perfringens type D is responsible for clinical signs and lesions of enterotoxemia, a predominantly neurological disease of sheep and goats. The role of ITX in disease of animals is poorly understood, although it is usually assumed that the pathogenesis of intestinal diseases produced by C. perfringens type E is mediated by this toxin. CPB2, a necrotizing and lethal toxin that can be produced by all types of C. perfringens, has been blamed for disease in many animal species, but little information is currently available to sustain or rule out this claim. CPE is an important virulence factor for C. perfringens type A gastrointestinal disease in humans and dogs; however, the data implicating CPE in other animal diseases remains ambiguous. PFO does not seem to play a direct role as the main virulence factor for animal diseases, but it may have a synergistic role with CPA-mediated gangrene and ETX-mediated enterotoxemia. The recent improvement of animal models for C. perfringens infection and the use of toxin gene knock-out mutants have demonstrated the specific pathogenic role of several toxins of C

  7. Electrochemical noise measurements during exfoliation of aluminum alloys

    SciTech Connect

    Damborenea, J. de; Fernandez, B.

    1996-12-31

    Aluminum alloys are one of the most widely used materials in the aerospace industry because of their intrinsic low density, high mechanical strength, and corrosion resistance. The performance of aircraft is improved by the use of lighter materials. Electrochemical noise measurements (ENMs) have been carried out during exfoliation corrosion of an aluminum-lithium alloy (8090) in the EXCO (ASTM Test Method for Exfoliation Corrosion Susceptibility in 2XXX and 7XXX Series Aluminum Alloys [EXCO Test] [G 34]) test solution. By means of the maximum entropy method (MEM), the potential and current fluctuations were converted into power spectral density (PSD) plots to study the specific variables related to electrochemical noise (low frequency amplitude, slopes). Noise resistance obtained from the standard deviation of potential and current was compared with the charge transference resistance (R{sub ct}) from electrochemical impedance spectroscopy (EIS) measurements. The results show that ENM can be used to detect early stages in localized corrosion. However, when the solution is very aggressive, indications of localized corrosion can be masked by uniform corrosion.

  8. Rockfall triggering by cyclic thermal stressing of exfoliation fractures

    NASA Astrophysics Data System (ADS)

    Collins, Brian D.; Stock, Greg M.

    2016-05-01

    Exfoliation of rock deteriorates cliffs through the formation and subsequent opening of fractures, which in turn can lead to potentially hazardous rockfalls. Although a number of mechanisms are known to trigger rockfalls, many rockfalls occur during periods when likely triggers such as precipitation, seismic activity and freezing conditions are absent. It has been suggested that these enigmatic rockfalls may occur due to solar heating of rock surfaces, which can cause outward expansion. Here we use data from 3.5 years of field monitoring of an exfoliating granite cliff in Yosemite National Park in California, USA, to assess the magnitude and temporal pattern of thermally induced rock deformation. From a thermodynamic analysis, we find that daily, seasonal and annual temperature variations are sufficient to drive cyclic and cumulative opening of fractures. Application of fracture theory suggests that these changes can lead to further fracture propagation and the consequent detachment of rock. Our data indicate that the warmest times of the day and year are particularly conducive to triggering rockfalls, and that cyclic thermal forcing may enhance the efficacy of other, more typical rockfall triggers.

  9. Sex identification from exfoliated primary teeth--a PCR study.

    PubMed

    Kumar, Manju Gopa; Hegde, Amitha M

    2005-01-01

    Teeth endure postmortem degradation and extreme changes in ambient temperature and pressure better than most human tissues. In the present day scenario the growing number of crime against children in the form of battering, physical/sexual abuse, abduction and kidnapping, the use of exfoliated primary teeth, become many times the only evidence available at the crime scene. Despite exposure of the body to burial, mutilation, explosion or incineration, it is usually possible to extract DNA from pulp tissue of tooth with sufficient quality and quantity. Hence the present study was undertaken to find out the sex of a child from exfoliated/extracted deciduous teeth using a Polymerase Chain reaction (PCR) based analysis. Tooth samples were stored in room temperature after double coding for various periods. Dental pulp tissue was collected from each sample and DNA was isolated by proteinase-k digestion and phenol chloroform extraction methods. PCR amplification was done with two sets of oligonucleiotide primers. Amplification of X (131bp) and Y-specific sequences (172bp) in males and that of the X-specific sequence in females was observed and compared with the template DNA showing male and female controls. Determination of sexes of all freshly collected samples within 24 hours and after 1 month of extraction respectively gave 100% result. However, PCR was not found to be an effective method for sex determination after 6 months post extraction. PMID:16302594

  10. Rockfall triggering by cyclic thermal stressing of exfoliation fractures

    USGS Publications Warehouse

    Collins, Brian; Stock, Greg M.

    2016-01-01

    Exfoliation of rock deteriorates cliffs through the formation and subsequent opening of fractures, which in turn can lead to potentially hazardous rockfalls. Although a number of mechanisms are known to trigger rockfalls, many rockfalls occur during periods when likely triggers such as precipitation, seismic activity and freezing conditions are absent. It has been suggested that these enigmatic rockfalls may occur due to solar heating of rock surfaces, which can cause outward expansion. Here we use data from 3.5 years of field monitoring of an exfoliating granite cliff in Yosemite National Park in California, USA, to assess the magnitude and temporal pattern of thermally induced rock deformation. From a thermodynamic analysis, we find that daily, seasonal and annual temperature variations are sufficient to drive cyclic and cumulative opening of fractures. Application of fracture theory suggests that these changes can lead to further fracture propagation and the consequent detachment of rock. Our data indicate that the warmest times of the day and year are particularly conducive to triggering rockfalls, and that cyclic thermal forcing may enhance the efficacy of other, more typical rockfall triggers.

  11. A Nanoporous Carbon/Exfoliated Graphite Composite For Supercapacitor Electrodes

    NASA Astrophysics Data System (ADS)

    Rosi, Memoria; Ekaputra, Muhamad P.; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal

    2010-12-01

    Nanoporous carbon was prepared from coconut shells using a simple heating method. The nanoporous carbon is subjected to different treatments: without activation, activation with polyethylene glycol (PEG), and activation with sodium hydroxide (NaOH)-PEG. The exfoliated graphite was synthesized from graphite powder oxidized with zinc acetate (ZnAc) and intercalated with polyvinyl alcohol (PVA) and NaOH. A composite was made by mixing the nanoporous carbon with NaOH-PEG activation, the exfoliated graphite and a binder of PVA solution, grinding the mixture, and annealing it using ultrasonic bath for 1 hour. All of as-synthesized materials were characterized by employing a scanning electron microscope (SEM), a MATLAB's image processing toolbox, and an x-ray diffractometer (XRD). It was confirmed that the composite is crystalline with (002) and (004) orientations. In addition, it was also found that the composite has a high surface area, a high distribution of pore sizes less than 40 nm, and a high porosity (67%). Noting that the pore sizes less than 20 nm are significant for ionic species storage and those in the range of 20 to 40 nm are very accessible for ionic clusters mobility across the pores, the composite is a promising material for the application as supercapacitor electrodes.

  12. Low temperature exfoliation process in hydrogen-implanted germanium layers

    NASA Astrophysics Data System (ADS)

    Ferain, I. P.; Byun, K. Y.; Colinge, C. A.; Brightup, S.; Goorsky, M. S.

    2010-03-01

    The feasibility of transferring hydrogen-implanted germanium to silicon with a reduced thermal budget is demonstrated. Germanium samples were implanted with a splitting dose of 5×1016 H2+ cm-2 at 180 keV and a two-step anneal was performed. Surface roughness and x-ray diffraction pattern measurements, combined with cross-sectional TEM analysis of hydrogen-implanted germanium samples were carried out in order to understand the exfoliation mechanism as a function of the thermal budget. It is shown that the first anneal performed at low temperature (≤150 °C for 22 h) enhances the nucleation of hydrogen platelets significantly. The second anneal is performed at 300 °C for 5 min and is shown to complete the exfoliation process by triggering the formation of extended platelets. Two key results are highlighted: (i) in a reduced thermal budget approach, the transfer of hydrogen-implanted germanium is found to follow a mechanism similar to the transfer of hydrogen-implanted InP and GaAs, (ii) such a low thermal budget (<300 °C) is found to be suitable for directly bonded heterogeneous substrates, such as germanium bonded to silicon, where different thermal expansion coefficients are involved.

  13. Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

    SciTech Connect

    Gayathri, S.; Jayabal, P.; Ramakrishnan, V.; Kottaisamy, M.

    2014-02-15

    The exfoliation of graphene from pristine graphite in a liquid phase was achieved successfully via sonication followed by centrifugation method. Ultraviolet–visible (UV–vis) spectra of the obtained graphene dispersions at different exfoliation time indicated that the concentration of graphene dispersion increased markedly with increasing exfoliation time. The sheet-like morphology of the exfoliated graphene was revealed by Scanning Electron Microscopy (SEM) image. Further, the morphological change in different exfoliation time was investigated by Atomic Force Microscopy (AFM). A complete structural and defect characterization was probed using micro-Raman spectroscopic technique. The shape and position of the 2D band of Raman spectra revealed the formation of bilayer to few layer graphene. Also, Raman mapping confirmed the presence of uniformly distributed bilayer graphene sheets on the substrate.

  14. Fluid replacement protection of rabbits challenged subcutaneous with toxic shock syndrome toxins.

    PubMed Central

    Lee, P K; Deringer, J R; Kreiswirth, B N; Novick, R P; Schlievert, P M

    1991-01-01

    Toxic shock syndrome toxin 1 (TSST-1) and streptococcal pyrogenic exotoxin A (SPE A) belong to a family of pyrogenic toxins produced by Staphylococcus aureus and Streptococcus pyogenes, respectively. Both toxins are responsible for causing toxic shock syndrome (TSS) and related illnesses, clinically characterized by multiorgan involvement. The most severe TSS symptom is acute hypotension and shock after the initial febrile response. In this study, we examined possible mechanisms of shock development in TSS, particularly the role of T-cell proliferation, endotoxin enhancement by toxins, and capillary leakage. American Dutch belted rabbits, with subcutaneously implanted miniosmotic pumps filled with either TSST-1 or SPE A, served as the animal model. For both TSST-1 and SPE A-treated rabbits, administration of cyclosporin A prevented toxin-induced T-cell proliferation but failed to protect the rabbits. Polymyxin B treatment of rabbits, to neutralize endogenous endotoxin, partially protected rabbits from challenge with either exotoxin; two of six rabbits survived on day 2 when treated with only TSST-1, whereas six of six animals survived after challenge with TSST-1 and polymyxin B. Similarly, with SPE A-treated rabbits, only 1 of 10 animals without polymyxin B treatment survived on day 8, but 4 of 6 rabbits survived on day 8 when given polymyxin B. Fluid replacement was successful in preventing lethality. Twelve of 14 rabbits survived when given TSST-1 with fluid, and all rabbits treated with SPE A and fluid survived. Finally, by using miniosmotic pumps, staphylococcal exfoliative toxin A and concanavalin A were administered to rabbits in an attempt to induce lethality. These two T-cell mitogens caused T-cell proliferation but failed to induce lethality in rabbits. The data suggest that toxin interactions causing vascular leakage and to some extent endotoxin enhancement are of major importance in development of hypotension and shock in TSS. It appears that T

  15. Cholera toxin, LT-I, LT-IIa, and LT-IIb: the critical role of ganglioside-binding in immunomodulation by Type I and Type II heat-labile enterotoxins

    PubMed Central

    Connell, Terry D.

    2010-01-01

    The heat-labile enterotoxins (HLT) expressed by Vibrio cholerae (cholera toxin) and Escherichia coli (LT-I, LT-IIa, and LT-IIb) are potent systemic and mucosal adjuvants. Co-administration of the enterotoxins with a foreign antigen (Ag) produces an augmented immune response to that antigen. Although each enterotoxin has potent adjuvant properties, the means by which the enterotoxins induce various immune responses are distinctive for each adjuvant. Various mutants have been engineered to dissect the functions of the enterotoxins required for their adjuvanticity. The capacity to strongly bind to one or more specific ganglioside receptors appears to drive the distinctive immunomodulatory properties associated with each enterotoxin. Mutant enterotoxins with ablated or altered ganglioside binding affinities have been employed to investigate the role of gangliosides in enterotoxin-dependent immunomodulation. PMID:17931161

  16. Two Shiga toxin 2 subtypes in a single Shiga toxin-producing Escherichia coli analyzed by RT-qPCR, MALDI-TOF-TOF-MS and top-down proteomic analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) are increasingly linked to outbreaks of foodborne illness worldwide. Shiga toxin (Stx) is an AB5 toxin with an A-subunit and five identical B-subunits. Amino acid sequence differences between Stx types and subtypes result in differences in toxicity. I...

  17. Continuous evolution of Bacillus thuringiensis toxins overcomes insect resistance.

    PubMed

    Badran, Ahmed H; Guzov, Victor M; Huai, Qing; Kemp, Melissa M; Vishwanath, Prashanth; Kain, Wendy; Nance, Autumn M; Evdokimov, Artem; Moshiri, Farhad; Turner, Keith H; Wang, Ping; Malvar, Thomas; Liu, David R

    2016-05-01

    The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd = 11-41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects. PMID:27120167

  18. Toxins and drug discovery.

    PubMed

    Harvey, Alan L

    2014-12-15

    Components from venoms have stimulated many drug discovery projects, with some notable successes. These are briefly reviewed, from captopril to ziconotide. However, there have been many more disappointments on the road from toxin discovery to approval of a new medicine. Drug discovery and development is an inherently risky business, and the main causes of failure during development programmes are outlined in order to highlight steps that might be taken to increase the chances of success with toxin-based drug discovery. These include having a clear focus on unmet therapeutic needs, concentrating on targets that are well-validated in terms of their relevance to the disease in question, making use of phenotypic screening rather than molecular-based assays, and working with development partners with the resources required for the long and expensive development process. PMID:25448391

  19. The cytological diagnosis of nasopharyngeal carcinoma from exfoliated cells collected by suction method. An eight-year experience.

    PubMed

    Hanji, D; Shujing, S; Shuwei, H; Gohao, L

    1983-08-01

    A specially designed metallic tube, which is connected to a suction-pump and passed through the oral cavity into the nasopharynx for collecting exfoliative cells by negative pressure suction, is recommended in the diagnosis of nasopharyngeal carcinoma (NPC). From the beginning of 1973 through October 1976, among 458 cases of NPC, 405 cases were cytologically positive (with a positive rate of 88.4 per cent), and 433 cases were biopsy positive (with a positive rate of 94.3 per cent). In 1977, from January to October, among 116 cases of NPC, 103 cases were cytologically positive (with a positive rate of 88.8 per cent), and 108 cases were biopsy positive (with a positive rate of 93.1 per cent). The cytopathological features of the exfoliative NPC cells were correlated with the histopathological types of NPC. The degree of lymphocytic infiltration among the cancer cells in smears was compared with that in biopsies. They coincided roughly with each other. It indicates that one might interpret the immunological lymphocytic reaction by the number and typing of lymphocytes in smears too. The authors conclude that this cytological method is fairly dependable, less traumatic to the mucosa, convenient, and easily managed. A large number of tumor cells can be collected. It can also reflect the histologic typing of cancer cells. It can be used as a routine procedure in the clinico-pathological diagnosis of NPC, as well as in a mass screening program. PMID:6350514

  20. Identification and apoptotic potential of T-2 toxin metabolites in human cells.

    PubMed

    Weidner, Maria; Welsch, Tanja; Hübner, Florian; Schwerdt, Gerald; Gekle, Michael; Humpf, Hans-Ulrich

    2012-06-01

    The mycotoxin T-2 toxin, produced by various Fusarium species, is a widespread contaminant of grain and grain products. Knowledge about its toxicity and metabolism in the human body is crucial for any risk assessment as T-2 toxin can be detected in processed and unprocessed food samples. Cell culture studies using cells of human origin represent a potent model system to study the metabolic fate of T-2 toxin as well as the cytotoxicity in vitro. In this study the metabolism of T-2 toxin was analyzed in a cell line derived from human colon carcinoma cells (HT-29) and primary human renal proximal tubule epithelial cells (RPTEC) using high-performance liquid chromatography coupled with Fourier transformation mass spectrometry (HPLC-FTMS). Both cell types metabolized T-2 toxin to a variety of compounds. Furthermore, cell cycle analysis in RPTEC proved the apoptotic effect of T-2 toxin and its metabolites HT-2 toxin and neosolaniol in micromolar concentrations. PMID:22551244

  1. SHIGA TOXIN BACTERIOPHAGE INSERTION SITES IDENTIFY DIVERSE ESCHERIHICA COLI O157:H7 STRAIN TYPES WITH DISTRIBUTIONS BIASED TO THE BOVINE HOST RESERVOIR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The incidence of human disease caused by E. coli O157:H7 is surprisingly low considering its ubiquitous distribution (and frequently, high prevalence) in the bovine reservoir and its low infectious dose for humans. The purpose of this study was to detect E. coli O157:H7 strain types in t...

  2. Method for detecting biological toxins

    SciTech Connect

    Ligler, F.S.; Campbell, J.R.

    1992-01-01

    Biological toxins are indirectly detected by using polymerase chain reaction to amplify unique nucleic acid sequences coding for the toxins or enzymes unique to toxin synthesis. Buffer, primers coding for the unique nucleic acid sequences and an amplifying enzyme are added to a sample suspected of containing the toxin. The mixture is then cycled thermally to exponentially amplify any of these unique nucleic acid sequences present in the sample. The amplified sequences can be detected by various means, including fluorescence. Detection of the amplified sequences is indicative of the presence of toxin in the original sample. By using more than one set of labeled primers, the method can be used to simultaneously detect several toxins in a sample.

  3. Evaluation of group versus individual physiotherapy following lower limb intra-muscular Botulinum Toxin-Type A injections for ambulant children with cerebral palsy: A single-blind randomized comparison trial.

    PubMed

    Thomas, Rachel E; Johnston, Leanne M; Sakzewski, Leanne; Kentish, Megan J; Boyd, Roslyn N

    2016-01-01

    This study aimed to evaluate efficacy of group (GRP) versus individual (IND) physiotherapy rehabilitation following lower limb intramuscular injections of Botulinum Toxin-Type A (BoNT-A) for ambulant children with cerebral palsy (CP). Following lower limb BoNT-A injections, 34 children were randomly allocated to GRP (n=17; mean age 7y8m SD 2.0; 13 males; Gross Motor Function Classification System (GMFCS) I=5, II=8, III=4) or IND physiotherapy (n=17; mean age 8y7m SD 2.0; 11 males; GMFCS I=9, II=5, III=3). Primary outcomes were the Canadian Occupational Performance Measure (COPM) and Edinburgh Visual Gait Score (EVGS) assessed at baseline, 10 and 26 weeks post intervention. There were no baseline differences between groups. GRP intervention had greater, but not clinically meaningful, improvement in COPM satisfaction (estimated mean difference EMD 1.7, 95% CI 0.4-3.1; p<0.01) at 26 weeks. Both groups demonstrated clinically significant improvements in COPM performance and satisfaction, but minimal change in quality of gait (EVGS). Six hours of direct physiotherapy (either GRP or IND) with an additional indirect dose (median 16 episodes) of individualized home programme activities following lower limb BoNT-A injections, however, was inadequate to drive clinically meaningful changes in lower limb motor outcomes. PMID:26955912

  4. Evaluating Functional Outcomes of Botulinum Toxin Type A Injection Combined with Occupational Therapy in the Upper Limbs of Children with Cerebral Palsy: A 9-Month Follow-Up from the Perspectives of Both Child and Caregiver

    PubMed Central

    Lin, Yu-Ching; Huang, Chien-Yu; Lin, I-Ling; Shieh, Jeng-Yi; Chung, Yu-Ting; Chen, Kuan-Lin

    2015-01-01

    Objective To assess the effectiveness of combining botulinum toxin type A (BoNT-A) with functional occupational therapy (OT) at 9-month follow-up in children with cerebral palsy (CP) with bilateral upper limb impairments from the perspectives of both child and caregiver. Methods Twelve children with CP and their caregivers were assessed across 5 time points over 9 months based on the ICF after BoNT-A injection and functional OT in this open-label study. Results Significant differences were found across the 5 time points (p < .05) for both grasp and visual-motor integration with small effects (effect sizes = 0.12–0.24) and the self-care capability and performance of social function (p < .05). However, based on the effect sizes (0.02–0.14), no significant effects were found at the 4 post-test time points. Small effects were found on the psychological domain (effect sizes = 0.25–0.37) and environmental domains (effect size = 0.27) at follow-ups. Conclusion Combining a BoNT-A injection with OT not only reduced the muscle tone and increased ROM but also improved the upper limb function and self-care capability in children with CP. More importantly, these effects persisted for up to 9 months. Functional OT extends the effectiveness of a BoNT-A injection. PMID:26599003

  5. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Longo, Simona; Mauro, Marco; Daniel, Christophe; Galimberti, Maurizio; Guerra, Gaetano

    2013-11-01

    Supercritical carbon dioxide (scCO2) treatments of a montmorillonite (MMT) intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT) led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS), have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals.

  6. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    PubMed Central

    Longo, Simona; Mauro, Marco; Daniel, Christophe; Galimberti, Maurizio; Guerra, Gaetano

    2013-01-01

    Supercritical carbon dioxide (scCO2) treatments of a montmorillonite (MMT) intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT) led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS), have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals. PMID:24790956

  7. Recombinant Toxins for Cancer Treatment

    NASA Astrophysics Data System (ADS)

    Pastan, Ira; Fitzgerald, David

    1991-11-01

    Recombinant toxins target cell surface receptors and antigens on tumor cells. They kill by mechanisms different from conventional chemotherapy, so that cross resistance to conventional chemotherapeutic agents should not be a problem. Furthermore, they are not mutagens and should not induce secondary malignancies or accelerate progression of benign malignancies. They can be mass-produced cheaply in bacteria as homogeneous proteins. Either growth factor-toxin fusions or antibody-toxin fusions can be chosen, depending on the cellular target.

  8. Toxin Plasmids of Clostridium perfringens

    PubMed Central

    Li, Jihong; Adams, Vicki; Bannam, Trudi L.; Miyamoto, Kazuaki; Garcia, Jorge P.; Uzal, Francisco A.; Rood, Julian I.

    2013-01-01

    SUMMARY In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  9. Ricin detection: tracking active toxin.

    PubMed

    Bozza, William P; Tolleson, William H; Rosado, Leslie A Rivera; Zhang, Baolin

    2015-01-01

    Ricin is a plant toxin with high bioterrorism potential due to its natural abundance and potency in inducing cell death. Early detection of the active toxin is essential for developing appropriate countermeasures. Here we review concepts for designing ricin detection methods, including mechanism of action of the toxin, advantages and disadvantages of current detection assays, and perspectives on the future development of rapid and reliable methods for detecting ricin in environmental samples. PMID:25481398

  10. Liquid-phase exfoliated graphene: functionalization, characterization, and applications.

    PubMed

    Quintana, Mildred; Tapia, Jesús Iván; Prato, Maurizio

    2014-01-01

    The development of chemical strategies to render graphene viable for incorporation into devices is a great challenge. A promising approach is the production of stable graphene dispersions from the exfoliation of graphite in water and organic solvents. The challenges involve the production of a large quantity of graphene sheets with tailored distribution in thickness, size, and shape. In this review, we present some of the recent efforts towards the controlled production of graphene in dispersions. We also describe some of the chemical protocols that have provided insight into the vast organic chemistry of the single atomic plane of graphite. Controlled chemical reactions applied to graphene are expected to significantly improve the design of hierarchical, functional platforms, driving the inclusion of graphene into advanced functional materials forward. PMID:25551061

  11. Exfoliated graphite-ruthenium oxide composite electrodes for electrochemical supercapacitors

    NASA Astrophysics Data System (ADS)

    Mitra, Sagar; Lokesh, K. S.; Sampath, S.

    The performance of exfoliated graphite (EG)-ruthenium oxide (RuO x) composites as binderless electrodes is evaluated for electrochemical capacitors (ECs). A composite of EG-RuO x is prepared by a modified sol-gel process. The material is characterized using X-ray diffraction and microscopy. Electrochemical capacitors with the composite electrodes in the presence of aqueous sulfuric acid (H 2SO 4) electrolyte are evaluated using voltammetry, impedance and charge-discharge studies. Cyclic voltammetry reveals very stable current-voltage behaviour up to several thousands of cycles, as well as high specific capacitances, e.g., a few hundreds of farads per gram for the composite that contains 16.5 wt.% RuO x.

  12. Quantitative risk stratification of oral leukoplakia with exfoliative cytology.

    PubMed

    Liu, Yao; Li, Jianying; Liu, Xiaoyong; Liu, Xudong; Khawar, Waqaar; Zhang, Xinyan; Wang, Fan; Chen, Xiaoxin; Sun, Zheng

    2015-01-01

    Exfoliative cytology has been widely used for early diagnosis of oral squamous cell carcinoma (OSCC). Test outcome is reported as "negative", "atypical" (defined as abnormal epithelial changes of uncertain diagnostic significance), and "positive" (defined as definitive cellular evidence of epithelial dysplasia or carcinoma). The major challenge is how to properly manage the "atypical" patients in order to diagnose OSCC early and prevent OSCC. In this study, we collected exfoliative cytology data, histopathology data, and clinical data of normal subjects (n=102), oral leukoplakia (OLK) patients (n=82), and OSCC patients (n=93), and developed a data analysis procedure for quantitative risk stratification of OLK patients. This procedure involving a step called expert-guided data transformation and reconstruction (EdTAR) which allows automatic data processing and reconstruction and reveals informative signals for subsequent risk stratification. Modern machine learning techniques were utilized to build statistical prediction models on the reconstructed data. Among the several models tested using resampling methods for parameter pruning and performance evaluation, Support Vector Machine (SVM) was found to be optimal with a high sensitivity (median>0.98) and specificity (median>0.99). With the SVM model, we constructed an oral cancer risk index (OCRI) which may potentially guide clinical follow-up of OLK patients. One OLK patient with an initial OCRI of 0.88 developed OSCC after 40 months of follow-up. In conclusion, we have developed a statistical method for qualitative risk stratification of OLK patients. This method may potentially improve cost-effectiveness of clinical follow-up of OLK patients, and help design clinical chemoprevention trial for high-risk populations. PMID:25978541

  13. Exfoliation and intercalation of montmorillonite by small peptides

    PubMed Central

    Block, Karin A.; Trusiak, Adrianna; Katz, Al; Alimova, Alexandra; Wei, Hui; Gottlieb, Paul; Steiner, Jeffrey C.

    2015-01-01

    Understanding structural changes in clay minerals induced by complexation with organic matter is relevant to soil science and agricultural applications. In this study, the effect of peptide storage in montmorillonite and the thermal stability of peptide-clay complexes was examined through characterization by X-ray diffraction (XRD), electron microscopy, UV absorption, and thermogravimetric analysis (TGA). XRD analysis of small peptide-montmorillonite clay complexes produced profiles consisting of reflections associated with the smectite 001 reflection and related peaks similar to that produced by a mixed layer clay mineral structure. Shifts in higher order diffraction maxima were attributed to disorder caused by the intercalation with the peptides. Increasing peptide concentrations resulted in greater shifts towards smaller 2θ from 6.37° (1.39 nm) to 5.45° (1.62 nm) as the interlayer space expanded. The expansion was accompanied by broadening of the 001 reflection (FWHM increases from 0.51 to 1.22° 2θ). The XRD line broadening was interpreted as caused by poorer crystallinity resulting from intercalation and tactoid exfoliation. SEM images revealed montmorillonite platelets with upwardly rolled edges that tend toward cylindrical structures with the production of tubules. High-resolution TEM images revealed bending of montmorillonite platelets, confirming exfoliation. The distribution of basal spacings in the micrographs was determined from the spatial frequencies obtained by Fourier analysis of density profiles. The distribution indicated the presence of discrete coherent crystallite domains. XRD and TGA results indicated that higher peptide concentrations resulted in a greater fraction of intercalated peptides and that surface adsorption of peptides mediated intercalation. Therefore, higher peptide concentration led to more stable organoclay complexes. However, UV absorption and TGA found that peptide adsorption onto montmorillonite had a finite limit at

  14. Staphylococcus aureus β-toxin Production is Common in Strains With the β-toxin Gene Inactivated by Bacteriophage

    PubMed Central

    Salgado-Pabón, Wilmara; Herrera, Alfa; Vu, Bao G.; Stach, Christopher S.; Merriman, Joseph A.; Spaulding, Adam R.; Schlievert, Patrick M.

    2014-01-01

    Background. Staphylococcus aureus causes life-threatening infections, including infective endocarditis, sepsis, and pneumonia. β-toxin is a sphingomyelinase encoded for by virtually all S. aureus strains and exhibits human immune cell cytotoxicity. The toxin enhances S. aureus phenol-soluble modulin activity, and its activity is enhanced by superantigens. The bacteriophage φSa3 inserts into the β-toxin gene in human strains, inactivating it in the majority of S. aureus clonal groups. Hence, most strains are reported not to secrete β-toxin. Methods. This dynamic was investigated by examining β-toxin production by multiple clonal groups of S. aureus, both in vitro and in vivo during infections in rabbit models of infective endocarditis, sepsis, and pneumonia. Results. β-toxin phenotypic variants are common among strains containing φSa3. In vivo, φSa3 is differentially induced in heart vegetations, kidney abscesses, and ischemic liver compared to spleen and blood, and in vitro growth in liquid culture. Furthermore, in pneumonia, wild-type β-toxin production leads to development of large caseous lesions, and in infective endocarditis, increases the size of pathognomonic vegetations. Conclusions. This study demonstrates the dynamic interaction between S. aureus and the infected host, where φSa3 serves as a regulator of virulence gene expression, and increased fitness and virulence in new environments. PMID:24620023

  15. Toxin-associated and other genes in Clostridium perfringens type A isolates from bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS).

    PubMed

    Schlegel, Benjamin J; Nowell, Victoria J; Parreira, Valeria R; Soltes, Glenn; Prescott, John F

    2012-10-01

    This study examined known or possible virulence-associated genes in type A Clostridium perfringens from cases of both bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS) and compared these to isolates from calves that were healthy or had undifferentiated diarrheal illness. A real-time polymerase chain reaction (PCR) assay was used to genotype the 218 C. perfringens isolates. Isolates were sourced from healthy and diarrheic young and mature cattle (n = 191), from calves with confirmed or suspected BCA (n = 22), and from mature cattle with JHS (n = 5). Of 216 isolates (96%), 208 were positive for the cpa gene and 13% (29/218) were positive for atypical cpb2. Three of 8 (37.5%) confirmed BCA isolates, 2 of 13 (15.4%) suspected BCA isolates, and no JHS isolates tested positive for atypical cpb2. As all isolates were negative for cpb, cpb2, cpe, etx, netB, and tpeL, the results of the present study do not support a role for these genes in BCA or JHS. A subset of unique genes identified in 1 bovine clostridial abomasitis isolate (F262), for which a genome sequence is available, was searched for in 8 BCA isolates by PCR. None of the 10 genes was consistently present in all or even in a majority of BCA isolates. Many of these genes were also variably and inconsistently present in type A isolates from calves that did not have BCA. Although a virulence signature to aid in the diagnosis of BCA caused by C. perfringens type A was not identified, further work may discover a gene or group of genes that would constitute such a signature. PMID:23543949

  16. Toxin-associated and other genes in Clostridium perfringens type A isolates from bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS)

    PubMed Central

    Schlegel, Benjamin J.; Nowell, Victoria J.; Parreira, Valeria R.; Soltes, Glenn; Prescott, John F.

    2012-01-01

    This study examined known or possible virulence-associated genes in type A Clostridium perfringens from cases of both bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS) and compared these to isolates from calves that were healthy or had undifferentiated diarrheal illness. A real-time polymerase chain reaction (PCR) assay was used to genotype the 218 C. perfringens isolates. Isolates were sourced from healthy and diarrheic young and mature cattle (n = 191), from calves with confirmed or suspected BCA (n = 22), and from mature cattle with JHS (n = 5). Of 216 isolates (96%), 208 were positive for the cpa gene and 13% (29/218) were positive for atypical cpb2. Three of 8 (37.5%) confirmed BCA isolates, 2 of 13 (15.4%) suspected BCA isolates, and no JHS isolates tested positive for atypical cpb2. As all isolates were negative for cpb, cpb2, cpe, etx, netB, and tpeL, the results of the present study do not support a role for these genes in BCA or JHS. A subset of unique genes identified in 1 bovine clostridial abomasitis isolate (F262), for which a genome sequence is available, was searched for in 8 BCA isolates by PCR. None of the 10 genes was consistently present in all or even in a majority of BCA isolates. Many of these genes were also variably and inconsistently present in type A isolates from calves that did not have BCA. Although a virulence signature to aid in the diagnosis of BCA caused by C. perfringens type A was not identified, further work may discover a gene or group of genes that would constitute such a signature. PMID:23543949

  17. Low defect concentration few-layer graphene using a two-step electrochemical exfoliation

    NASA Astrophysics Data System (ADS)

    Huang, Xuhua; Li, Senlin; Qi, Zhiqiang; Zhang, Wei; Ye, Wei; Fang, Yanyan

    2015-03-01

    Low defect concentration few-layer graphene (FLG) sheets were fabricated by a two-step electrochemical intercalation exfoliation, including a graphite foil pretreatment in sodium hydroxide solution and a subsequent further exfoliation in sulfuric acid solution. During the process, the pretreatment results in the expansion of the graphite foil and in turn facilitates the final exfoliation in sulfuric acid solution. The results show that the ID/IG of the obtained FLG sheets is as low as 0.29 while maintaining relatively high yield, more than 56%. In addition, the oxygen content in the FLG sheets is 8.32% with the C/O ratio of 11.02.

  18. Liquid-phase exfoliated graphene self-assembled films: Low-frequency noise and thermal-electric characterization

    NASA Astrophysics Data System (ADS)

    Tubon Usca, G.; Hernandez-Ambato, J.; Pace, C.; Caputi, L. S.; Tavolaro, A.

    2016-09-01

    In few years, graphene has become a revolutionary material, leading not only to applications in various fields such as electronics, medicine and environment, but also to the production of new types of 2D materials. In this work, Liquid Phase Exfoliation (LPE) was applied to natural graphite by brief sonication or mixer treatment in suitable solvents, in order to produce Few Layers Graphene (FLG) suspensions. Additionally, zeolite 4A (Z4A) was added during the production of FLG flakes-based inks, with the aim of aiding the exfoliation process. Conductive films were obtained by drop casting three types of suspensions over Al2O3 substrates with interdigitated electrodes, with total channel surface of 1.39 mm2. The morphology characterization resulted in the verification of the presence of thin self-assembled flakes. Raman studies gave evidence of 4 to 10 layers graphene flakes. Electrical measurements were performed to state the Low-Frequency Noise and Thermal-Electric characteristics of the samples. We observe interesting relations between sample preparation procedures and electrical properties.

  19. Passive immunization with antiserum to a nontoxic alpha-toxin mutant from Staphylococcus aureus is protective in a murine model.

    PubMed Central

    Menzies, B E; Kernodle, D S

    1996-01-01

    A nonhemolytic, nonlethal variant of Staphylococcus aureus alpha-toxin constructed via oligonucleotide-directed mutagenesis and containing a single amino acid substitution (H-35 to L) was used to immunize a rabbit. The resulting antiserum was cross-reactive with wild-type alpha-toxin and neutralized its hemolytic activity in vitro. Passive immunization of mice with rabbit antiserum conferred protection against lethal challenge with wild-type alpha-toxin and against acute lethal challenge with a high-alpha-toxin -producing S. aureus strain. H35L alpha-toxin may be useful as a protective immunogen in S. aureus vaccine studies. PMID:8613399

  20. Release from Th1-type immune tolerance in spleen and enhanced production of IL-5 in Peyer's patch by cholera toxin B induce the glomerular deposition of IgA.

    PubMed

    Yamanaka, Takahiro; Tamauchi, Hidekazu; Suzuki, Yusuke; Suzuki, Hitoshi; Horikoshi, Satoshi; Terashima, Masazumi; Iwabuchi, Kazuya; Habu, Sonoko; Okumura, Ko; Tomino, Yasuhiko

    2016-04-01

    We examined the pathogenesis of glomerular damage in Th2 type-dependent GATA-3 transgenic (GATA-3 Tg) mice with IgA nephropathy (IgAN). GATA-3 Tg mice were immunized orally using OVA plus cholera toxin B (CTB), and measurement of the serum IgA antibody level and histopathological examination were performed. Marked increases in the serum levels of OVA-specific IgA antibody, IgA and IgG, C3 deposits analogous to those seen in IgAN, and expansion of the matrix in association with mesangial cell proliferation were observed. Furthermore, glomerular IgA deposits were co-localized with mannan-binding lectin (MBL) deposits, which might actually have been abnormal IgA deposits. In GATA-3/TCR-Tg mice that had been orally sensitized with CTB plus OVA and were re-stimulated with OVA in vitro, cultured Peyer's patch cells showed the enhanced production of IL-5 and supernatants from cultures of spleen cells showed a reduction of TGF-β production with a simultaneous increase in IL-2 production and the recovery of IFN-γ formation. The amount of TGF-β produced by the spleen cells was found to be correlated with the amount of IFN-γ and IL-IL-2 produced by the cells. Also, the percentage of regulatory T cells (Treg) in the spleens of mice sensitized with OVA plus CTB was lower than that in mice orally sensitized with OVA alone. These results suggest that the increased production of IL-5 from Peyer's patch cells (PPc) and the restored Th1-type immune response might cause the production of abnormal IgA and might induce the deposition of IgA in glomeruli. PMID:26719095

  1. Identification of the cellular receptor for anthrax toxin

    NASA Astrophysics Data System (ADS)

    Bradley, Kenneth A.; Mogridge, Jeremy; Mourez, Michael; Collier, R. John; Young, John A. T.

    2001-11-01

    The tripartite toxin secreted by Bacillus anthracis, the causative agent of anthrax, helps the bacterium evade the immune system and can kill the host during a systemic infection. Two components of the toxin enzymatically modify substrates within the cytosol of mammalian cells: oedema factor (OF) is an adenylate cyclase that impairs host defences through a variety of mechanisms including inhibiting phagocytosis; lethal factor (LF) is a zinc-dependent protease that cleaves mitogen-activated protein kinase kinase and causes lysis of macrophages. Protective antigen (PA), the third component, binds to a cellular receptor and mediates delivery of the enzymatic components to the cytosol. Here we describe the cloning of the human PA receptor using a genetic complementation approach. The receptor, termed ATR (anthrax toxin receptor), is a type I membrane protein with an extracellular von Willebrand factor A domain that binds directly to PA. In addition, a soluble version of this domain can protect cells from the action of the toxin.

  2. The setting of a botulinum toxin treatment service.

    PubMed

    Cavallini, Maurizio

    2014-05-01

    The administration of botulinum toxin is an activity performed mostly by a specialist service for the management of a wide range of neurological conditions. For therapeutic purposes botulinum toxin type A is used, although in selected patients who develop antibodies specific for the serotype A botulinum toxin B can be used for the treatment. Hereby, we describe the organizational arrangements for the botulinum toxin treatment service at the Department of Neurology of Hospital Cardinal Massaia based in Asti. The diseases most frequently treated are movement disorders (primary and secondary focal dystonia, blepharospasm, facial emispasmo) spasticity and, more recently, chronic migraine. In particular, the latter application is one of the most promising expansions of the use of this drug in the few past years, although a larger number of patients are required to determine its efficacy and the related tolerability profile. PMID:24867836

  3. Tracing the metabolism of HT-2 toxin and T-2 toxin in barley by isotope-assisted untargeted screening and quantitative LC-HRMS analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An extensive study of the metabolism of the type-A trichothecene mycotoxins HT-2 toxin and T-2 toxin in barley using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) is reported. A recently developed untargeted approach based on stable isotopic labelling, LC-Orbitrap-MS a...

  4. Naturally acquired antibodies against Clostridium perfringens epsilon toxin in goats.

    PubMed

    Veschi, Josir Laine A; Bruzzone, Octavio A; Losada-Eaton, Daniela M; Dutra, Iveraldo S; Fernandez-Miyakawa, Mariano E

    2008-09-15

    Clostridium perfringens type D-producing epsilon toxin is a common cause of death in sheep and goats worldwide. Although anti-epsilon toxin serum antibodies have been detected in healthy non-vaccinated sheep, the information regarding naturally acquired antibodies in ruminants is scanty. The objective of the present report was to characterize the development of naturally acquired antibodies against C. perfringens epsilon toxin in goats. The levels of anti-epsilon toxin antibodies in blood serum of goat kids from two different herds were examined continuously for 14 months. Goats were not vaccinated against any clostridial disease and received heterologous colostrums from cows that were not vaccinated against any clostridial disease. During the survey one of these flocks suffered an unexpectedly severe C. perfringens type D enterotoxemia outbreak. The results showed that natural acquired antibodies against C. perfringens epsilon toxin can appear as early as 6 weeks in young goats and increase with the age without evidence of clinical disease. The enterotoxemia outbreak was coincident with a significant increase in the level of anti-epsilon toxin antibodies. PMID:18538416

  5. Neurotoxic potential and cellular uptake of T-2 toxin in human astrocytes in primary culture.

    PubMed

    Weidner, Maria; Lenczyk, Marlies; Schwerdt, Gerald; Gekle, Michael; Humpf, Hans-Ulrich

    2013-03-18

    The trichothecene mycotoxin T-2 toxin, which is produced by fungi of the Fusarium species, is a worldwide occurring contaminant of cereal based food and feed. The cytotoxic properties of T-2 toxin are already well described with apoptosis being a major mechanism of action in various cell lines as well as in primary cells of different origin. However, only few data on neurotoxic properties of T-2 toxin are reported so far, but in vivo studies showed different effects of T-2 toxin on behavior as well as on levels of brain amines in animals. To further investigate the cytotoxic properties of T-2 toxin on cells derived from brain tissue, normal human astrocytes in primary culture (NHA) were used in this study. Besides studies of cytotoxicity, apoptosis (caspase-3-activation, Annexin V) and necrosis (LDH-release), the cellular uptake and metabolism of T-2 toxin in NHA was analyzed and compared to the uptake in an established human cell line (HT-29). The results show that human astrocytes were highly sensitive to the cytotoxic properties of T-2 toxin, and apoptosis, induced at low concentrations, was identified for the first time as the mechanism of toxic action in NHA. Furthermore, a strong accumulation of T-2 toxin in NHA and HT-29 cells was detected, and T-2 toxin was subjected to metabolism leading to HT-2 toxin, a commonly found metabolite after T-2 toxin incubation in both cell types. This formation seems to occur within the cells since incubations of T-2 toxin with cell depleted culture medium did not lead to any degradation of the parent toxin. The results of this study emphasize the neurotoxic potential of T-2 toxin in human astrocytes at low concentrations after short incubation times. PMID:23363530

  6. Effects of botulinum toxin type A facial injection on monoamines and their metabolites in sensory, limbic and motor brain regions in rats.

    PubMed

    Ibragić, S; Matak, I; Dračić, A; Smajlović, A; Muminović, M; Proft, F; Sofić, E; Lacković, Z; Riederer, P

    2016-03-23

    Despite its toxicity, botulinum neurotoxin type A (BTX-A) is a valuable therapeutic agent for several motor, autonomic and pain disorders. Numerous studies have described its peripheral as well as central effects. Using reversed-phase High Performance Liquid Chromatography with Electrochemical Detection (HPLC-ED) and gradient elution, we quantified the concentrations of dopamine (DA), noradrenaline (NA), serotonin (5-HT) and their metabolites in 10 brain regions, ipsilateral and contralateral from the site of unilateral BTX-A administration (5U/kg) into the rat whisker pad. In regions associated with nociception and pain processing we also examined possible BTX-A effects in combination with formalin-induced inflammatory orofacial pain. The dominant BTX-A effects on the monoamines and their metabolites were insignificant. The only significant increase caused by BTX-A alone was that of NA in striatum and serotonin in hypothalamus. While antinociceptive effects of BTX-A are most probably not related to central monoamine concentrations, the localized increased NA and 5-HT concentrations might play a role in reported BTX-A efficacy for the treatment of depression. PMID:26876447

  7. Lymphocyte receptors for pertussis toxin

    SciTech Connect

    Clark, C.G.; Armstrong, G.D. )

    1990-12-01

    We have investigated human T-lymphocyte receptors for pertussis toxin by affinity isolation and photoaffinity labeling procedures. T lymphocytes were obtained from peripheral human blood, surface iodinated, and solubilized in Triton X-100. The iodinated mixture was then passed through pertussis toxin-agarose, and the fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of the fixed, dried gels revealed several bands in the pertussis toxin-bound fraction that were not observed in fractions obtained from histone or fetuin-agarose. Further investigations employed a photoaffinity labeling reagent, sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate, to identify pertussis toxin receptors in freshly isolated peripheral blood monocytic cells, T lymphocytes, and Jurkat cells. In all three cell systems, the pertussis toxin affinity probe specifically labeled a single protein species with an apparent molecular weight of 70,000 that was not observed when the procedure was performed in the presence of excess unmodified pertussis toxin. A protein comparable in molecular weight to the one detected by the photoaffinity labeling technique was also observed among the species that bound to pertussis toxin-agarose. The results suggest that pertussis toxin may bind to a 70,000-Da receptor in human T lymphocytes.

  8. The assay of diphtheria toxin

    PubMed Central

    Gerwing, Julia; Long, D. A.; Mussett, Marjorie V.

    1957-01-01

    A precise assay of diphtheria toxin is described, based on the linear relationship between the diameter of the skin reaction to, and logarithm of the dose of, toxin. It eliminates the need for preliminary titrations, is economical, provides information about the slope of the log-dose response lines and, therefore, of the validity of the assay, and yields limits of error of potency from the internal evidence of the assay. A study has been made of the effects of avidity, combining power, toxicity and buffering on the assay of diphtheria toxins against the International Standards for both Diphtheria Antitoxin and Schick-Test Toxin. All the toxins assayed against the standard toxin, whatever their other properties might be, gave log-dose response lines of similar slope provided that they were diluted in buffered physiological saline. The assays were therefore valid. These experiments were repeated concurrently in non-immune and in actively immunized guinea-pigs, and comparable figures for potency obtained in both groups. The result was not significantly affected by the avidity or combining power of the toxin. However, non-avid toxins gave low values in Schick units when assayed, by the Römer & Sames technique, in terms of the International Standard for Diphtheria Antitoxin. The problem of the ultimate standard and the implications of these findings are discussed. PMID:13511133

  9. TOXINS FROM CYANOBACTERIA IN WATER

    EPA Science Inventory

    This project is part of a larger U. S. Environmental Protection Agency (EPA) effort, which includes the Office of Water, to investigate algal toxins in surface water supplies and drinking water. Toxins produced by cyanobacteria (blue-green algae) are among the most potent known ...

  10. Botulinum toxin: Bioweapon & magic drug

    PubMed Central

    Dhaked, Ram Kumar; Singh, Manglesh Kumar; Singh, Padma; Gupta, Pallavi

    2010-01-01

    Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle associated proteins responsible for acetylcholine release into the neuromuscular junction. As a military or terrorist weapon, botulinum toxin could be disseminated via aerosol or by contamination of water or food supplies, causing widespread casualties. A fascinating aspect of botulinum toxin research in recent years has been development of the most potent toxin into a molecule of significant therapeutic utility. It is the first biological toxin which is licensed for treatment of human diseases. In the late 1980s, Canada approved use of the toxin to treat strabismus, in 2001 in the removal of facial wrinkles and in 2002, the FDA in the United States followed suit. The present review focuses on both warfare potential and medical uses of botulinum neurotoxin. PMID:21149997

  11. Micromechanical exfoliation of two-dimensional materials by a polymeric stamp

    NASA Astrophysics Data System (ADS)

    Ferraz da Costa, M. C.; Ribeiro, H. B.; Kessler, F.; de Souza, E. A. T.; Fechine, G. J. M.

    2016-02-01

    In this work, an alternative technique to the traditional micromechanical exfoliation of two-dimensional materials is proposed, consisting of isolated flakes of graphite and molybdenum disulphide onto polymeric surfaces films. The set made up of polymer and flakes is fabricated by using a hot-press machine called polymeric stamp. The polymeric stamp was used to allocate flakes and also to allow the exfoliation process to take place just in one face of isolated flake. Optical microscopy, Raman spectroscopy and photoluminescence spectroscopy results showed that multilayers, bilayers and single layers of graphene and MoS2 were obtained by using a polymeric stamp as tool for micromechanical exfoliation. These crystals were more easily found because the exfoliation process concentrates them in well-defined locations. The results prove the effectiveness of the method by embedding two-dimensional materials into polymers to fabricate fewer layers crystals in a fast, economic and clean way.

  12. Controlled Exfoliation of MoS2 Crystals into Trilayer Nanosheets.

    PubMed

    Fan, Xiaobin; Xu, Pengtao; Li, Yuguang C; Zhou, Dekai; Sun, Yifan; Nguyen, Minh An T; Terrones, Mauricio; Mallouk, Thomas E

    2016-04-20

    The controlled exfoliation of transition metal dichalcogenides (TMDs) into pristine single- or few-layer nanosheets remains a significant barrier to fundamental studies and device applications of TMDs. Here we report a novel strategy for exfoliating crystalline MoS2 into suspensions of nanosheets with retention of the semiconducting 2H phase. The controlled reaction of MoS2 with substoichiometric amounts n-butyllithium results in intercalation of the edges of the crystals, which are then readily exfoliated in a 45 vol % ethanol-water solution. Surprisingly, the resulting colloidal suspension of nanosheets was found (by electron microscopy and atomic force microscopy) to consist mostly of trilayers. The efficiency of exfoliation of the pre-intercalated sample is increased by at least 1 order of magnitude relative to the starting MoS2 microcrystals, with a mass yield of the dispersed nanosheets of 11-15%. PMID:27031870

  13. Role of Peroxide Ions in Formation of Graphene Nanosheets by Electrochemical Exfoliation of Graphite

    PubMed Central

    Rao, Kodepelly Sanjeeva; Senthilnathan, Jaganathan; Liu, Yung-Fang; Yoshimura, Masahiro

    2014-01-01

    This study demonstrates a facile, mild and environmentally-friendly sustainable (soft processing) approach for the efficient electrochemical exfoliation of graphite using a sodium hydroxide/hydrogen peroxide/water (NaOH/H2O2/H2O) system that can produce high-quality, anodic few-layer graphene nanosheets in 95% yield at ambient reaction conditions. The control experiment conducted using NaOH/H2O revealed the crucial role of H2O2 in the exfoliation of graphite. A possible exfoliation mechanism is proposed. The reaction of H2O2 with hydroxyl ions (HO−) leads to the formation of highly nucleophilic peroxide ions (O22−), which play a crucial role in the exfoliation of graphite via electrochemical-potential-assisted intercalation and strong expansion of graphite sheets. PMID:24577336

  14. Mechanism of Exfoliation and Prediction of Materials Properties of Clay-Polymer Nanocomposites from Multiscale Modeling.

    PubMed

    Suter, James L; Groen, Derek; Coveney, Peter V

    2015-12-01

    We describe the mechanism that leads to full exfoliation and dispersion of organophilic clays when mixed with molten hydrophilic polymers. This process is of fundamental importance for the production of clay-polymer nanocomposites with enhanced materials properties. The chemically specific nature of our multiscale approach allows us to probe how chemistry, in combination with processing conditions, produces such materials properties at the mesoscale and beyond. In general agreement with experimental observations, we find that a higher grafting density of charged quaternary ammonium surfactant ions promotes exfoliation, by a mechanism whereby the clay sheets slide transversally over one another. We can determine the elastic properties of these nanocomposites; exfoliated and partially exfoliated morphologies lead to substantial enhancement of the Young's modulus, as found experimentally. PMID:26575149

  15. Role of Peroxide Ions in Formation of Graphene Nanosheets by Electrochemical Exfoliation of Graphite

    NASA Astrophysics Data System (ADS)

    Rao, Kodepelly Sanjeeva; Senthilnathan, Jaganathan; Liu, Yung-Fang; Yoshimura, Masahiro

    2014-02-01

    This study demonstrates a facile, mild and environmentally-friendly sustainable (soft processing) approach for the efficient electrochemical exfoliation of graphite using a sodium hydroxide/hydrogen peroxide/water (NaOH/H2O2/H2O) system that can produce high-quality, anodic few-layer graphene nanosheets in 95% yield at ambient reaction conditions. The control experiment conducted using NaOH/H2O revealed the crucial role of H2O2 in the exfoliation of graphite. A possible exfoliation mechanism is proposed. The reaction of H2O2 with hydroxyl ions (HO-) leads to the formation of highly nucleophilic peroxide ions (O22-), which play a crucial role in the exfoliation of graphite via electrochemical-potential-assisted intercalation and strong expansion of graphite sheets.

  16. Preparation of titanate nanosheets and nanoribbons by exfoliation of amine intercalated titanates.

    PubMed

    Jeffery, A Anto; Pradeep, A; Rajamathi, Michael

    2016-05-14

    Amine intercalated titanates were synthesized by direct exchange of potassium ions of K2Ti4O9 by alkyl ammonium ions of various alkyl chain lengths. These intercalated solids exfoliate well in alcohols of different alkyl chain lengths and non-polar solvents such as toluene and hexane to yield colloidal dispersions of titanate nanosheets. The longer the alkyl chain of the intercalated amine the better the exfoliation of the intercalated titanate in long chain alcohols and non-polar solvents. While non-uniform rectangular nanosheets were obtained when aggressive sonication was employed for exfoliating the solids, nanoribbons were obtained when the exfoliation was carried out by gently stirring the solids in the solvent. PMID:27089839

  17. Packaging material and flexible medical tubing containing thermally exfoliated graphite oxide

    NASA Technical Reports Server (NTRS)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A packaging material or flexible medical tubing containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

  18. Low pH-Induced Pore Formation by the T Domain of Botulinum Toxin Type A is Dependent upon NaCl Concentration

    SciTech Connect

    Lai, B.; Swaminathan, S.; Agarwal, R.; Nelson, L. D.; London, E.

    2010-07-19

    Botulinum neurotoxins (BoNTs) undergo low pH-triggered membrane insertion, resulting in the translocation of their light (catalytic) chains into the cytoplasm. The T (translocation) domain of the BoNT heavy chain is believed to carry out translocation. Here, the behavior of isolated T domain from BoNT type A has been characterized, both in solution and when associated with model membranes. When BoNT T domain prepared in the detergent dodecylmaltoside was diluted into aqueous solution, it exhibited a low pH-dependent conformational change below pH 6. At low pH the T domain associated with, and formed pores within, model membrane vesicles composed of 30 mol% dioleoylphosphatidylglycerol/70 mol% dioleoylphosphatidylcholine. Although T domain interacted with vesicles at low (50 mM) and high (400 mM) NaCl concentrations, the interaction required much less lipid at low salt. However, even at high lipid concentrations pore formation was much more pronounced at low NaCl concentrations than at high NaCl concentration. Increasing salt concentration after insertion in the presence of 50 mM NaCl did not decrease pore formation. A similar effect of NaCl concentration upon pore formation was observed in vesicles composed solely of dioleoylphosphatidylcholine, showing that the effect of NaCl did not solely involve modulation of electrostatic interactions between protein and anionic lipids. These results indicate that some feature of membrane-bound T domain tertiary structure critical for pore formation is highly dependent upon salt concentration.

  19. Elevated levels of maternal anti-tetanus toxin antibodies do not suppress the immune response to a Haemophilus influenzae type b polyribosylphosphate-tetanus toxoid conjugate vaccine.

    PubMed Central

    Panpitpat, C.; Thisyakorn, U.; Chotpitayasunondh, T.; Fürer, E.; Que, J. U.; Hasler, T.; Cryz, S. J.

    2000-01-01

    Reported are the effects of elevated levels of anti-tetanus antibodies on the safety and immune response to a Haemophilus influenzae type b polyribosylphosphate (PRP)-tetanus toxoid conjugate (PRP-T) vaccine. A group of Thai infants (n = 177) born to women immunized against tetanus during pregnancy were vaccinated with either a combined diphtheria-tetanus-pertussis (DTP) PRP-T vaccine or DTP and a PRP-conjugate vaccine using Neisseria meningitidis group B outer-membrane proteins as a carrier (PedVax HIB). Although most infants possessed high titres (> 1 IU/ml) of anti-tetanus antibodies, the DTP-PRP-T combined vaccine engendered an excellent antibody response to all vaccine components. In both vaccine groups > 98% of infants attained anti-PRP antibody titres > or = 0.15 microgram/ml. The geometric mean anti-PRP antibody titres were 5.41 micrograms/ml and 2.1 micrograms/ml for infants immunized with three doses of PRP-T versus two doses of PedVax HIB vaccines, respectively (P < 0.005). Similarly, the proportion of infants who achieved titres > or = 1 microgram/ml was higher in the PRP-T group (87.8%) than in the group immunized with PedVax HIB (74.2%) (P = 0.036). A subgroup analysis showed that there was no significant difference in the anti-PRP antibody response for infants exhibiting either < 1 IU of anti-tetanus antibody per millilitre or > or = 1 IU/ml at baseline. These finding indicate that pre-existing anti-carrier antibody does not diminish the immune response to the PRP moiety. All infants possessed protective levels of anti-D and anti-T antibody levels after immunization. PMID:10812736

  20. Immunofluorescent Detection of Herpesvirus Antigens in Exfoliated Cells from Human Cervical Carcinoma

    PubMed Central

    Royston, Ivor; Aurelian, Laure

    1970-01-01

    Exfoliated cells from patients with squamous carcinoma of the cervix contain antigens related to herpesvirus subtype 2, as revealed by direct or indirect immunofluorescent techniques. Normal squamous cells from the same subjects and from controls without the disease, and cells from a small number of tumors at sites other than the cervix, did not react with anti-herpesvirus subtype 2 serum. Antisera to adenovirus 18 or mycoplasma orale did not react with the exfoliated cells. Images PMID:4318779

  1. Binding of ATP by pertussis toxin and isolated toxin subunits

    SciTech Connect

    Hausman, S.Z.; Manclark, C.R.; Burns, D.L. )

    1990-07-03

    The binding of ATP to pertussis toxin and its components, the A subunit and B oligomer, was investigated. Whereas, radiolabeled ATP bound to the B oligomer and pertussis toxin, no binding to the A subunit was observed. The binding of ({sup 3}H)ATP to pertussis toxin and the B oligomer was inhibited by nucleotides. The relative effectiveness of the nucleotides was shown to be ATP > GTP > CTP > TTP for pertussis toxin and ATP > GTP > TTP > CTP for the B oligomer. Phosphate ions inhibited the binding of ({sup 3}H)ATP to pertussis toxin in a competitive manner; however, the presence of phosphate ions was essential for binding of ATP to the B oligomer. The toxin substrate, NAD, did not affect the binding of ({sup 3}H)ATP to pertussis toxin, although the glycoprotein fetuin significantly decreased binding. These results suggest that the binding site for ATP is located on the B oligomer and is distinct from the enzymatically active site but may be located near the eukaryotic receptor binding site.

  2. Comparison of human mesenchymal stem cells derived from bone marrow, synovial fluid, adult dental pulp, and exfoliated deciduous tooth pulp.

    PubMed

    Isobe, Y; Koyama, N; Nakao, K; Osawa, K; Ikeno, M; Yamanaka, S; Okubo, Y; Fujimura, K; Bessho, K

    2016-01-01

    Populations of pluripotent stem cells were isolated from bone marrow, synovial fluid, adult dental pulp, and exfoliated deciduous teeth and their multipotentiality properties compared. Osteogenic, chondrogenic, adipogenic, and neurogenic differentiation potentials were examined. Bone marrow mesenchymal stem cells (BMMSCs) and synovial fluid-derived cells (SFCs) showed the highest levels of osteogenesis as expressed by alkaline phosphatase (ALP) activity (0.54±0.094 U/mg protein and 0.57±0.039 U/mg protein, respectively; P=0.60) and by osteocalcin (BGLAP; determined by real-time RT-PCR). SFCs showed the highest levels of chondrogenesis as expressed by ALP activity (1.75±0.097 U/mg protein) and of COL2A1 and COL10A1 by real-time PCR. In terms of adipogenesis, lipid vesicles were observed in the BMMSCs and SFCs. Dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHED) exhibited neurogenesis potential, as shown by increases in expression of class III β-tubulin (TUBB3) and microtubule-associated protein 2 (MAP2) on RT-PCR. Variability was found in the differentiation potential corresponding to the tendency of the original tissue to differentiate. It is suggested that the cell type should be selected depending on the regenerative treatment regimen. PMID:26235629

  3. Atom-Thin SnS2-xSex with Adjustable Compositions by Direct Liquid Exfoliation from Single Crystals.

    PubMed

    Yang, Zhanhai; Liang, Hui; Wang, Xusheng; Ma, Xinlei; Zhang, Tao; Yang, Yanlian; Xie, Liming; Chen, Dong; Long, Yujia; Chen, Jitao; Chang, Yunjie; Yan, Chunhua; Zhang, Xinxiang; Zhang, Xueji; Ge, Binghui; Ren, Zhian; Xue, Mianqi; Chen, Genfu

    2016-01-26

    Two-dimensional (2D) chalcogenide materials are fundamentally and technologically fascinating for their suitable band gap energy and carrier type relevant to their adjustable composition, structure, and dimensionality. Here, we demonstrate the exfoliation of single-crystal SnS2-xSex (SSS) with S/Se vacancies into an atom-thin layer by simple sonication in ethanol without additive. The introduction of vacancies at the S/Se site, the conflicting atomic radius of sulfur in selenium layers, and easy incorporation with an ethanol molecule lead to high ion accessibility; therefore, atom-thin SSS flakes can be effectively prepared by exfoliating the single crystal via sonication. The in situ pyrolysis of such materials can further adjust their compositions, representing tunable activation energy, band gap, and also tunable response to analytes of such materials. As the most basic and crucial step of the 2D material field, the successful synthesis of an uncontaminated and atom-thin sample will further push ahead the large-scale applications of 2D materials, including, but not limited to, electronics, sensing, catalysis, and energy storage fields. PMID:26690902

  4. LT-IIb(T13I), a non-toxic type II heat-labile enterotoxin, augments the capacity of a ricin toxin subunit vaccine to evoke neutralizing antibodies and protective immunity.

    PubMed

    Greene, Christopher J; Chadwick, Chrystal M; Mandell, Lorrie M; Hu, John C; O'Hara, Joanne M; Brey, Robert N; Mantis, Nicholas J; Connell, Terry D

    2013-01-01

    Currently, there is a shortage of adjuvants that can be employed with protein subunit vaccines to enhance protection against biological threats. LT-IIb(T13I) is an engineered nontoxic derivative of LT-IIb, a member of the type II subfamily of heat labile enterotoxins expressed by Escherichia coli, that possesses potent mucosal adjuvant properties. In this study we evaluated the capacity of LT-IIb(T13I) to augment the potency of RiVax, a recombinant ricin toxin A subunit vaccine, when co-administered to mice via the intradermal (i.d.) and intranasal (i.n.) routes. We report that co-administration of RiVax with LT-IIb(T13I) by the i.d. route enhanced the levels of RiVax-specific serum IgG antibodies (Ab) and elevated the ratio of ricin-neutralizing to non-neutralizing Ab, as compared to RiVax alone. Protection against a lethal ricin challenge was also augmented by LT-IIb(T13I). While local inflammatory responses elicited by LT-IIb(T13I) were comparable to those elicited by aluminum salts (Imject®), LT-IIb(T13I) was more effective than aluminum salts at augmenting production of RiVax-specific serum IgG. Finally, i.n. administration of RiVax with LT-IIb(T13I) also increased levels of RiVax-specific serum and mucosal Ab and enhanced protection against ricin challenge. Collectively, these data highlight the potential of LT-IIb(T13I) as an effective next-generation i.d., or possibly i.n. adjuvant for enhancing the immunogenicity of subunit vaccines for biodefense. PMID:23936344

  5. Polymer reinforcement using liquid-exfoliated boron nitride nanosheets

    NASA Astrophysics Data System (ADS)

    Khan, Umar; May, Peter; O'Neill, Arlene; Bell, Alan P.; Boussac, Elodie; Martin, Arnaud; Semple, James; Coleman, Jonathan N.

    2012-12-01

    We have exfoliated hexagonal boron nitride by ultrasonication in solutions of polyvinylalcohol in water. The resultant nanosheets are sterically stabilised by adsorbed polymer chains. Centrifugation-based size-selection was used to give dispersions of nanosheets with aspect ratio (length/thickness) of ~1400. Such dispersions can be used to produce polyvinylalcohol-BN composite films. Helium ion microscopy of fracture surfaces shows the nanosheets to be well dispersed and the composites to fail by pull-out. We find both modulus, Y, and strength, σB, of these composites to increase linearly with volume fraction, Vf, up to Vf ~ 0.1 vol% BN before falling off. The rates of increase are extremely high; dY/dVf = 670 GPa and dσB/dVf = 47 GPa. The former value matches theory based on continuum mechanics while the latter value is consistent with remarkably high polymer-filler interfacial strength. However, because the mechanical properties increase over such a narrow volume fraction range, the maximum values of both modulus and strength are only ~40% higher than the pure polymer. This phenomenon has also been observed for graphene-filled composites and represents a serious hurdle to the production of high performance polymer-nanosheet composites.We have exfoliated hexagonal boron nitride by ultrasonication in solutions of polyvinylalcohol in water. The resultant nanosheets are sterically stabilised by adsorbed polymer chains. Centrifugation-based size-selection was used to give dispersions of nanosheets with aspect ratio (length/thickness) of ~1400. Such dispersions can be used to produce polyvinylalcohol-BN composite films. Helium ion microscopy of fracture surfaces shows the nanosheets to be well dispersed and the composites to fail by pull-out. We find both modulus, Y, and strength, σB, of these composites to increase linearly with volume fraction, Vf, up to Vf ~ 0.1 vol% BN before falling off. The rates of increase are extremely high; dY/dVf = 670 GPa and d

  6. DNA-Assisted Exfoliation of Tungsten Dichalcogenides and Their Antibacterial Effect.

    PubMed

    Bang, Gyeong Sook; Cho, Suhyung; Son, Narae; Shim, Gi Woong; Cho, Byung-Kwan; Choi, Sung-Yool

    2016-01-27

    This study reports a method for the facile and high-yield exfoliation of WX2 (X = S, Se) by sonication under aqueous conditions using single-stranded DNA (abbreviated as ssDNA) of high molecular weight. The ssDNA provided a high degree of stabilization and prevented reaggregation, and it enhanced the exfoliation efficiency of WX2 nanosheets due to adsorption on the WX2 surface and the electrostatic repulsion of sugars in the ssDNA backbone. The exfoliation yield was higher with ssDNA (80%-90%) than without (2%-4%); the yield with ssDNA was also higher than the value previously reported for aqueous exfoliation (∼10%). Given that two-dimensional nanomaterials have potential health and environmental applications, we investigated antibacterial activity of exfoliated WX2-ssDNA nanosheets, relative to graphene oxide (GO), and found that WSe2-ssDNA nanosheets had higher antibacterial activity against Escherichia coli K-12 MG1655 cells than GO. Our method enables large-scale exfoliation in an aqueous environment in a single step with a short reaction time and under ambient conditions, and it can be used to produce surface-active or catalytic materials that have broad applications in biomedicine and other areas. PMID:26734845

  7. Imidazolium salts as small-molecule urinary bladder exfoliants in a murine model.

    PubMed

    Wagers, Patrick O; Tiemann, Kristin M; Shelton, Kerri L; Kofron, William G; Panzner, Matthew J; Wooley, Karen L; Youngs, Wiley J; Hunstad, David A

    2015-09-01

    We present a novel family of small-molecule urinary bladder exfoliants that are expected to be of great value in preclinical studies of urologic conditions and have improved potential for translation compared with prior agents. There is broad urologic interest in the therapeutic potential of such exfoliating agents. The primary agent used in preclinical models, the cationic peptide protamine sulfate (PS), has limited translational potential due to concerns including systemic adverse reactions and bladder tissue injury. Intravesical application of a safe, systemically nontoxic exfoliant would have potential utility in the eradication of Escherichia coli and other uropathogens that reside in the bladder epithelium following cystitis, as well as in chronic bladder pain and bladder cancer. Here, we introduce a family of imidazolium salts with potent and focused exfoliating activity on the bladder epithelium. Synthesis and purification were straightforward and scalable, and the compounds exhibited prolonged stability in lyophilized form. Most members of the compound family were cytotoxic to cultured uroepithelial cells, with >10-fold differences in potency across the series. Upon topical (intravesical) administration of selected compounds to the murine bladder, complete epithelial exfoliation was achieved with physiologically relevant imidazolium concentrations and brief contact times. The exfoliative activity of these compounds was markedly improved in comparison to PS, as assessed by microscopy, immunofluorescence, and immunoblotting for uroplakins. Bladder uroepithelium regenerated within days to yield a histologically normal appearance, and no toxicity was observed. Finally, the chemical scaffold offers an opportunity for inclusion of antimicrobials or conjugation with chemotherapeutic or other moieties. PMID:26124168

  8. Controlling the number of graphene sheets exfoliated from graphite by designed normal loading and frictional motion

    SciTech Connect

    Lee, Seungjun; Lu, Wei

    2014-07-14

    We use molecular dynamics to study the exfoliation of patterned nanometer-sized graphite under various normal loading conditions for friction-induced exfoliation. Using highly ordered pyrolytic graphite (HOPG) as well as both amorphous and crystalline SiO{sub 2} substrate as example systems, we show that the exfoliation process is attributed to the corrugation of the HOPG surface and the atomistic roughness of the substrate when they contact under normal loading. The critical normal strain, at which the exfoliation occurs, is higher on a crystalline substrate than on an amorphous substrate. This effect is related to the atomistic flatness and stiffness of the crystalline surface. We observe that an increase of the van der Waals interaction between the graphite and the substrate results in a decrease of the critical normal strain for exfoliation. We find that the magnitude of the normal strain can effectively control the number of exfoliated graphene layers. This mechanism suggests a promising approach of applying designed normal loading while sliding to pattern controlled number of graphene layers or other two-dimensional materials on a substrate surface.

  9. Imidazolium Salts as Small-Molecule Urinary Bladder Exfoliants in a Murine Model

    PubMed Central

    Wagers, Patrick O.; Tiemann, Kristin M.; Shelton, Kerri L.; Kofron, William G.; Panzner, Matthew J.; Wooley, Karen L.; Youngs, Wiley J.

    2015-01-01

    We present a novel family of small-molecule urinary bladder exfoliants that are expected to be of great value in preclinical studies of urologic conditions and have improved potential for translation compared with prior agents. There is broad urologic interest in the therapeutic potential of such exfoliating agents. The primary agent used in preclinical models, the cationic peptide protamine sulfate (PS), has limited translational potential due to concerns including systemic adverse reactions and bladder tissue injury. Intravesical application of a safe, systemically nontoxic exfoliant would have potential utility in the eradication of Escherichia coli and other uropathogens that reside in the bladder epithelium following cystitis, as well as in chronic bladder pain and bladder cancer. Here, we introduce a family of imidazolium salts with potent and focused exfoliating activity on the bladder epithelium. Synthesis and purification were straightforward and scalable, and the compounds exhibited prolonged stability in lyophilized form. Most members of the compound family were cytotoxic to cultured uroepithelial cells, with >10-fold differences in potency across the series. Upon topical (intravesical) administration of selected compounds to the murine bladder, complete epithelial exfoliation was achieved with physiologically relevant imidazolium concentrations and brief contact times. The exfoliative activity of these compounds was markedly improved in comparison to PS, as assessed by microscopy, immunofluorescence, and immunoblotting for uroplakins. Bladder uroepithelium regenerated within days to yield a histologically normal appearance, and no toxicity was observed. Finally, the chemical scaffold offers an opportunity for inclusion of antimicrobials or conjugation with chemotherapeutic or other moieties. PMID:26124168

  10. Serotypes, Virulence Genes, and Intimin Types of Shiga Toxin (Verotoxin)-Producing Escherichia coli Isolates from Cattle in Spain and Identification of a New Intimin Variant Gene (eae-ξ)

    PubMed Central

    Blanco, M.; Blanco, J. E.; Mora, A.; Dahbi, G.; Alonso, M. P.; González, E. A.; Bernárdez, M. I.; Blanco, J.

    2004-01-01

    A total of 514 Shiga toxin-producing Escherichia coli (STEC) isolates from diarrheic and healthy cattle in Spain were characterized in this study. PCR showed that 101 (20%) isolates carried stx1 genes, 278 (54%) possessed stx2 genes, and 135 (26%) possessed both stx1 and stx2. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 326 (63%) and in 151 (29%) of the isolates, respectively. STEC isolates belonged to 66 O serogroups and 113 O:H serotypes (including 23 new serotypes). However, 67% were of one of these 15 serogroups (O2, O4, O8, O20, O22, O26, O77, O91, O105, O113, O116, O157, O171, O174, and OX177) and 52% of the isolates belonged to only 10 serotypes (O4:H4, O20:H19, O22:H8, O26:H11, O77:H41, O105:H18, O113:H21, O157:H7, O171:H2, and ONT:H19). Although the 514 STEC isolates belonged to 164 different seropathotypes (associations between serotypes and virulence genes), only 12 accounted for 43% of isolates. Seropathotype O157:H7 stx2 eae-γ1 ehxA (46 isolates) was the most common, followed by O157:H7 stx1 stx2 eae-γ1 ehxA (34 isolates), O113:H21 stx2 (25 isolates), O22:H8 stx1 stx2 ehxA (15 isolates), O26:H11 stx1 eae-β1 ehxA (14 isolates), and O77:H41 stx2 ehxA (14 isolates). Forty-one (22 of serotype O26:H11) isolates had intimin β1, 82 O157:H7 isolates possessed intimin γ1, three O111:H- isolates had intimin type γ2, one O49:H- strain showed intimin type δ, 13 (six of serotype O103:H2) isolates had intimin type ɛ and eight (four of serotype O156:H-) isolates had intimin ζ. We have identified a new variant of the eae intimin gene designated ξ (xi) in two isolates of serotype O80:H-. The majority (85%) of bovine STEC isolates belonged to serotypes previously found for human STEC organisms and 54% to serotypes associated with STEC organisms isolated from patients with hemolytic uremic syndrome. Thus, this study confirms that cattle are a major reservoir of STEC strains pathogenic for humans. PMID:14766831

  11. Effect of epsilon toxin-GFP on MDCK cells and renal tubules in vivo.

    PubMed

    Soler-Jover, Alex; Blasi, Juan; Gómez de Aranda, Inma; Navarro, Piedad; Gibert, Maryse; Popoff, Michel R; Martín-Satué, Mireia

    2004-07-01

    Epsilon toxin (epsilon-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxemia, also known as pulpy kidney disease, in livestock. Recombinant epsilon-toxin-green fluorescence protein (epsilon-toxin-GFP) and epsilon-prototoxin-GFP were successfully expressed in Escherichia coli. MTT assays on MDCK cells confirmed that recombinant epsilon-toxin-GFP retained the cytotoxicity of the native toxin. Direct fluorescence analysis of MDCK cells revealed a homogeneous peripheral pattern that was temperature sensitive and susceptible to detergent. epsilon-Toxin-GFP and epsilon-prototoxin-GFP bound to endothelia in various organs of injected mice, especially the brain. However, fluorescence mainly accumulated in kidneys. Mice injected with epsilon-toxin-GFP showed severe kidney alterations, including hemorrhagic medullae and selective degeneration of distal tubules. Moreover, experiments on kidney cryoslices demonstrated specific binding to distal tubule cells of a range of species. We demonstrate with new recombinant fluorescence tools that epsilon-toxin binds in vivo to endothelial cells and renal tubules, where it has a strong cytotoxic effect. Our binding experiments indicate that an epsilon-toxin receptor is expressed on renal distal tubules of mammalian species, including human. PMID:15208360

  12. Overview of Botulinum Toxins for Aesthetic Uses.

    PubMed

    Gart, Michael S; Gutowski, Karol A

    2016-07-01

    Botulinum toxin type A (BTA) can be used for facial aesthetics. The 3 currently available BTA types include onabotulinumtoxinA (Botox; Botox Cosmetic, Allergan, Irvine, CA), abobotulinumtoxinA (Dysport; Ipsen, Ltd, Berkshire, UK), and incobotulinumtoxinA (Xeomin; Merz Pharmaceuticals, Frankfurt, Germany). The mechanism of action and clinical uses for treatment of dynamic lines of the forehead, brow, glabella, lateral orbit, nose, and lips are presented, as well as treatment of masseter hypertrophy, platysmal bands, and improvements of the perioral region. Specific BTA injection sites and suggested doses are presented. PMID:27363760

  13. Evaluation of antidiphtheria toxin nanobodies

    PubMed Central

    Shaker, Ghada H

    2010-01-01

    Nanobodies are the smallest fragments of naturally occurring single-domain antibodies that have evolved to be fully functional in the absence of a light chain. Conventional antibodies are glycoproteins comprising two heavy and two light chains. Surprisingly, all members of the Camelidae family possess a fraction of antibodies devoid of both light chains and the first constant domain. These types of antibodies are known as heavy-chain antibody (HcAb) nanobodies. There are three subclasses of IgG in dromedaries, namely IgG1, IgG2, and IgG3 of which IgG2 and IgG3 are of the HcAb type. These heavy chain antibodies constitute approximately 50% of the IgG in llama serum and as much as 75% of the IgG in camel serum. In the present work, the different IgG subclasses from an immunized camel (Camelus dromedarius) with divalent diphtheria-tetanus vaccine were purified using their different affinity for protein A and protein G and their absorbance measured at 280 nm. Purity control and characterization by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis of IgG subclasses was done under reducing conditions. Protein bands were visualized after staining with Coomassie Blue, showing two bands at 50 kDa and 30 kDa for IgG1, while IgG2 and IgG3 produced only one band at 46 kDa and 43 kDa, respectively. An enzyme-linked immunosorbent assay test using diphtheria toxin and purified IgG subclasses from the immunized camel were performed to evaluate their efficiency. Compared with conventional IgG1, heavy chain antibodies (nanobodies) were shown to be more efficient in binding to diphtheria toxin antigen. This study revealed the possibility of using IgG2 and IgG3 nanobodies as an effective antitoxin for the treatment of diphtheria in humans. PMID:24198468

  14. Channels Formed by Botulinum, Tetanus, and Diphtheria Toxins in Planar Lipid Bilayers: Relevance to Translocation of Proteins across Membranes

    NASA Astrophysics Data System (ADS)

    Hoch, David H.; Romero-Mira, Miryam; Ehrlich, Barbara E.; Finkelstein, Alan; Dasgupta, Bibhuti R.; Simpson, Lance L.

    1985-03-01

    The heavy chains of both botulinum neurotoxin type B and tetanus toxin form channels in planar bilayer membranes. These channels have pH-dependent and voltage-dependent properties that are remarkably similar to those previously described for diphtheria toxin. Selectivity experiments with anions and cations show that the channels formed by the heavy chains of all three toxins are large; thus, these channels could serve as ``tunnel proteins'' for translocation of active peptide fragments. These findings support the hypothesis that the active fragments of botulinum neurotoxin and tetanus toxin, like that of diphtheria toxin, are translocated across the membranes of acidic vesicles.

  15. Single photon emitters in exfoliated WSe2 structures.

    PubMed

    Koperski, M; Nogajewski, K; Arora, A; Cherkez, V; Mallet, P; Veuillen, J-Y; Marcus, J; Kossacki, P; Potemski, M

    2015-06-01

    Crystal structure imperfections in solids often act as efficient carrier trapping centres, which, when suitably isolated, act as sources of single photon emission. The best known examples of such attractive imperfections are well-width or composition fluctuations in semiconductor heterostructures (resulting in the formation of quantum dots) and coloured centres in wide-bandgap materials such as diamond. In the recently investigated thin films of layered compounds, the crystal imperfections may logically be expected to appear at the edges of commonly investigated few-layer flakes of these materials exfoliated on alien substrates. Here, we report comprehensive optical micro-spectroscopy studies of thin layers of tungsten diselenide (WSe2), a representative semiconducting dichalcogenide with a bandgap in the visible spectral range. At the edges of WSe2 flakes (transferred onto Si/SiO2 substrates) we discover centres that, at low temperatures, give rise to sharp emission lines (100 μeV linewidth). These narrow emission lines reveal the effect of photon antibunching, the unambiguous attribute of single photon emitters. The optical response of these emitters is inherently linked to the two-dimensional properties of the WSe2 monolayer, as they both give rise to luminescence in the same energy range, have nearly identical excitation spectra and have very similar, characteristically large Zeeman effects. With advances in the structural control of edge imperfections, thin films of WSe2 may provide added functionalities that are relevant for the domain of quantum optoelectronics. PMID:25938573

  16. Single photon emitters in exfoliated WSe2 structures

    NASA Astrophysics Data System (ADS)

    Koperski, M.; Nogajewski, K.; Arora, A.; Cherkez, V.; Mallet, P.; Veuillen, J.-Y.; Marcus, J.; Kossacki, P.; Potemski, M.

    2015-06-01

    Crystal structure imperfections in solids often act as efficient carrier trapping centres, which, when suitably isolated, act as sources of single photon emission. The best known examples of such attractive imperfections are well-width or composition fluctuations in semiconductor heterostructures (resulting in the formation of quantum dots) and coloured centres in wide-bandgap materials such as diamond. In the recently investigated thin films of layered compounds, the crystal imperfections may logically be expected to appear at the edges of commonly investigated few-layer flakes of these materials exfoliated on alien substrates. Here, we report comprehensive optical micro-spectroscopy studies of thin layers of tungsten diselenide (WSe2), a representative semiconducting dichalcogenide with a bandgap in the visible spectral range. At the edges of WSe2 flakes (transferred onto Si/SiO2 substrates) we discover centres that, at low temperatures, give rise to sharp emission lines (100 μeV linewidth). These narrow emission lines reveal the effect of photon antibunching, the unambiguous attribute of single photon emitters. The optical response of these emitters is inherently linked to the two-dimensional properties of the WSe2 monolayer, as they both give rise to luminescence in the same energy range, have nearly identical excitation spectra and have very similar, characteristically large Zeeman effects. With advances in the structural control of edge imperfections, thin films of WSe2 may provide added functionalities that are relevant for the domain of quantum optoelectronics.

  17. Humidity Effects and Anisotropic Etching During Exfoliated Black Phosphorus Degradation

    NASA Astrophysics Data System (ADS)

    Favron, Alexandre; Moraille, Patricia; Gaufres, Etienne; Roorda, Tycho; Levesque, Pierre L.; Leonelli, Richard; Martel, Richard

    Black phosphorus, a lamellar structure similar to graphene, is a high mobility semiconductor having a tunable optical band gap from 0.3 eV up to ~2 eV with decreasing layer thickness. Our previous study has highlighted a fast photo-oxidation in ambient conditions when black phosphorus is exfoliated as thin layers. The kinetics of this degradation is also enhanced by quantum confinement effects and faster for the thinnest layers, which represents an important hurdle to prepare few layers. Here we further investigate the role of water in the process by following the reaction kinetics in different humidity using fast AFM imaging. We report on important changes of wettability of thin layers at room temperature depending on the degradation stages and layer thickness. For a given level of humidity at equilibrium, we observe the formation of water droplets. Those droplets form preferentially on defects sites and cracks and then grow on the thicker parts of the flake to finally accumulate on to the thinnest regions. This sequence of water droplet growth faster from thick to thin layers is interpreted as being due to a lowering of surface tension with decreasing layer thickness. In a second study, the oxidation kinetics of layers completely immersed in water reveal an anisotropic oxidation process with preferential etching in specific orientations of the crystal. This study will be discussed in the context of a reactivity of black phosphorus that appears both anisotropic and thickness-dependent.

  18. Axonal Degeneration in Dental Pulp Precedes Human Primary Teeth Exfoliation.

    PubMed

    Suzuki, K; Lovera, M; Schmachtenberg, O; Couve, E

    2015-10-01

    The dental pulp in human primary teeth is densely innervated by a plethora of nerve endings at the coronal pulp-dentin interface. This study analyzed how the physiological root resorption (PRR) process affects dental pulp innervation before exfoliation of primary teeth. Forty-four primary canine teeth, classified into 3 defined PRR stages (early, middle, and advanced) were fixed and demineralized. Longitudinal cryosections of each tooth were stained for immunohistochemical and quantitative analysis of dental pulp nerve fibers and associated components with confocal and electron microscopy. During PRR, axonal degeneration was prominent and progressive in a Wallerian-like scheme, comprising nerve fiber bundles and nerve endings within the coronal and root pulp. Neurofilament fragmentation increased significantly during PRR progression and was accompanied by myelin degradation and a progressive loss of myelinated axons. Myelin sheath degradation involved activation of autophagic activity by Schwann cells to remove myelin debris. These cells expressed a sequence of responses comprising dedifferentiation, proliferative activity, GAP-43 overexpression, and Büngner band formation. During the advanced PRR stage, increased immune cell recruitment within the dental pulp and major histocompatibility complex (MHC) class II upregulation by Schwann cells characterized an inflammatory condition associated with the denervation process in preexfoliative primary teeth. The ensuing loss of dental pulp axons is likely to be responsible for the progressive reduction of sensory function of the dental pulp during preexfoliative stages. PMID:26149320

  19. Proton pump inhibitor-induced exfoliative dermatitis: A case report

    PubMed Central

    QIU, ZHIHONG; LIU, HONGTAO; HE, LIEN; MA, YINLING; SONG, HAOJING; BAI, WANJUN; YU, MEILING

    2016-01-01

    A 74-year-old female patient was admitted to hospital following a road accident with pains in the chest, abdomen, waist, back, nose, left wrist and lower limbs. After 1 week, the patient presented with gastrointestinal bleeding, and thus was treated with protein pump inhibitors (PPIs), including lansoprazole, esomeprazole and omeprazole enteric-coated tablets, in order to inhibit acid secretion and attenuate bleeding. However, the patient developed skin rashes on the chest and right lower limb and foot 28 days following treatment initiation. The skin rashes spread and ulcerated after 3 days, and were associated with tracheal mucosal injury and hemoptysis. Subsequently, treatment of the patient with PPIs was terminated, after which the tracheal hemoptysis and skin rashes markedly improved. In addition, no new skin rashes appeared following termination of the PPI treatment. In the present case, long-term treatment of an elderly patient with PPIs may have induced exfoliative dermatitis, due to hepatic ischemia, hypoxia and acute renal failure, which may have decreased the metabolism of PPIs, resulting in the accumulation of PPI metabolites. PMID:26893644

  20. Photooxidation and quantum confinement effects in exfoliated black phosphorus

    NASA Astrophysics Data System (ADS)

    Favron, Alexandre; Gaufrès, Etienne; Fossard, Frédéric; Phaneuf-L'Heureux, Anne-Laurence; Tang, Nathalie Y.-W.; Lévesque, Pierre L.; Loiseau, Annick; Leonelli, Richard; Francoeur, Sébastien; Martel, Richard

    2015-08-01

    Thin layers of black phosphorus have recently raised interest owing to their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of phosphorus atoms can be exfoliated down to monolayer 2D-phosphane (also called phosphorene) using procedures similar to those used for graphene. Probing the properties has, however, been challenged by a fast degradation of the thinnest layers on exposure to ambient conditions. Herein, we investigate this chemistry using in situ Raman and transmission electron spectroscopies. The results highlight a thickness-dependent photoassisted oxidation reaction with oxygen dissolved in adsorbed water. The oxidation kinetics is consistent with a phenomenological model involving electron transfer and quantum confinement as key parameters. A procedure carried out in a glove box is used to prepare mono-, bi- and multilayer 2D-phosphane in their pristine states for further studies on the effect of layer thickness on the Raman modes. Controlled experiments in ambient conditions are shown to lower the Ag1/Ag2 intensity ratio for ultrathin layers, a signature of oxidation.

  1. Differentiation-associated toxin receptor modulation, cytokine production, and sensitivity to Shiga-like toxins in human monocytes and monocytic cell lines.

    PubMed Central

    Ramegowda, B; Tesh, V L

    1996-01-01

    Infections with Shiga toxin-producing Shigella dysenteriae type 1 or Shiga-like toxin (SLT)-producing Escherichia coli cause bloody diarrhea and are associated with an increased risk of acute renal failure and severe neurological complications. Histopathological examination of human and animal tissues suggests that the target cells for toxin action are vascular endothelial cells. Proinflammatory cytokines regulate endothelial cell membrane expression of the glycolipid globotriaosylceramide (Gb(3)) which serves as the toxin receptor, suggesting that the host response to the toxins or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. We examined the effects of purified SLTs on human peripheral blood monocytes (PBMn) and two monocytic cell lines. Undifferentiated THP-1 cells were sensitive to SLTs. Treatment of the cells with a number of differentiation factors resulted in increased toxin resistance which was associated with decreased toxin receptor expression. U-937 cells, irrespective of maturation state, and PBMn were resistant to the toxins. U-937 cells expressed low levels of GB(3), and toxin receptor expression was not altered during differentiation. Treatment of monocytic cells with tumor necrosis factor alpha (TNF-alpha) did not markedly increase sensitivity or alter toxin receptor expression. Undifferentiated monocytic cells failed to synthesize TNF and interleukin 1beta when treated with sublethal concentrations of SLT type I (SLT-I), whereas cells treated with 12-0-tetradecanoylphorbol-13-acetate acquired the ability to produce cytokines when stimulated with SLT-I. When stimulated with SLT-I, U-937 cells produced lower levels of TNF than PBMn and THP-1 cells did. PMID:8606075

  2. Food toxin detection with atomic force microscope

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Externally introduced toxins or internal spoilage correlated pathogens and their metabolites are all potential sources of food toxins. To prevent and protect unsafe food, many food toxin detection techniques have been developed to detect various toxins for quality control. Although several routine m...

  3. Detecting and discriminating among Shiga toxins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The virulence associated with Shiga toxin producing Escherichia coli (STEC) infections is from the Shiga toxins produced by the E. coli strain. Although Shiga toxins are associated with E. coli, the expression of the toxins is actually controlled by a temperate lambdoid phage that infects the host. ...

  4. Botulinum toxin for pain.

    PubMed

    Casale, Roberto; Tugnoli, Valeria

    2008-01-01

    Botulinum toxin (BTX) injection is being increasingly used 'off label' in the management of chronic pain. Data support the hypothesis of a direct analgesic effect of BTX, different to that exerted on muscle. Although the pain-reducing effect of BTX is mainly due to its ability to block acetylcholine release at the synapse, other effects on the nervous system are also thought to be involved. BTX affects cholinergic transmission in both the somatic and the autonomic nervous systems. Proposed mechanisms of action of BTX for pain relief of trigger points, muscular spasms, fibromyalgia and myofascial pain include direct action on muscle and indirect effects via action at the neuromuscular junction. Invitro and invivo data have shown that BTX has specific antinociceptive activity relating to its effects on inflammation, axonal transport, ganglion inhibition, and spinal and suprasegmental level inhibition. Our review of the mechanisms of action, efficacy, administration techniques and therapeutic dosage of BTX for the management of chronic pain in a variety of conditions shows that although muscular tone and movement disorders remain the most important therapeutic applications for BTX, research suggests that BTX can also provide benefits related to effects on cholinergic control of the vascular system, autonomic function, and cholinergic control of nociceptive and antinociceptive systems. Furthermore, it appears that BTX may influence the peripheral and central nervous systems. The therapeutic potential of BTX depends mainly on the ability to deliver the toxin to the target structures, cholinergic or otherwise. Evidence suggests that BTX can be administered at standard dosages in pain disorders, where the objective is alteration of muscle tone. For conditions requiring an analgesic effect, the optimal therapeutic dosage of BTX remains to be defined. PMID:18095750

  5. Tarantula toxins use common surfaces for interacting with Kv and ASIC ion channels.

    PubMed

    Gupta, Kanchan; Zamanian, Maryam; Bae, Chanhyung; Milescu, Mirela; Krepkiy, Dmitriy; Tilley, Drew C; Sack, Jon T; Yarov-Yarovoy, Vladimir; Kim, Jae Il; Swartz, Kenton J

    2015-01-01

    Tarantula toxins that bind to voltage-sensing domains of voltage-activated ion channels are thought to partition into the membrane and bind to the channel within the bilayer. While no structures of a voltage-sensor toxin bound to a channel have been solved, a structural homolog, psalmotoxin (PcTx1), was recently crystalized in complex with the extracellular domain of an acid sensing ion channel (ASIC). In the present study we use spectroscopic, biophysical and computational approaches to compare membrane interaction properties and channel binding surfaces of PcTx1 with the voltage-sensor toxin guangxitoxin (GxTx-1E). Our results show that both types of tarantula toxins interact with membranes, but that voltage-sensor toxins partition deeper into the bilayer. In addition, our results suggest that tarantula toxins have evolved a similar concave surface for clamping onto α-helices that is effective in aqueous or lipidic physical environments. PMID:25948544

  6. Binding of epsilon-toxin from Clostridium perfringens in the nervous system.

    PubMed

    Dorca-Arévalo, Jonatan; Soler-Jover, Alex; Gibert, Maryse; Popoff, Michel R; Martín-Satué, Mireia; Blasi, Juan

    2008-09-18

    Epsilon-toxin (epsilon-toxin), produced by Clostridium perfringens type D, is the main agent responsible for enterotoxaemia in livestock. Neurological disorders are a characteristic of the onset of toxin poisoning. Epsilon-Toxin accumulates specifically in the central nervous system, where it produces a glutamatergic-mediated excitotoxic effect. However, no detailed study of putative binding structures in the nervous tissue has been carried out to date. Here we attempt to identify specific acceptor moieties and cell targets for epsilon-toxin, not only in the mouse nervous system but also in the brains of sheep and cattle. An epsilon-toxin-GFP fusion protein was produced and used to incubate brain sections, which were then analyzed by confocal microscopy. The results clearly show specific binding of epsilon-toxin to myelin structures. epsilon-Prototoxin-GFP and epsilon-toxin-GFP, the inactive and active forms of the toxin, respectively, showed identical results. By means of pronase E treatment, we found that the binding was mainly associated to a protein component of the myelin. Myelinated peripheral nerve fibres were also stained by epsilon-toxin. Moreover, the binding to myelin was not only restricted to rodents, but was also found in humans, sheep and cattle. Curiously, in the brains of both sheep and cattle, the toxin strongly stained the vascular endothelium, a result that may explain the differences in potency and effect between species. Although the binding of epsilon-toxin to myelin does not directly explain its neurotoxic effect, this feature opens up a new line of enquiry into its mechanism of toxicity and establishes the usefulness of this toxin for the study of the mammalian nervous system. PMID:18406080

  7. Shiga Toxin Producing Escherichia coli.

    PubMed

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli. PMID:26004641

  8. Diphtheria toxin-based targeted toxin therapy for brain tumors.

    PubMed

    Li, Yan Michael; Vallera, Daniel A; Hall, Walter A

    2013-09-01

    Targeted toxins (TT) are molecules that bind cell surface antigens or receptors such as the transferrin or interleukin-13 receptor that are overexpressed in cancer. After internalization, the toxin component kills the cell. These recombinant proteins consist of an antibody or carrier ligand coupled to a modified plant or bacterial toxin such as diphtheria toxin (DT). These fusion proteins are very effective against brain cancer cells that are resistant to radiation therapy and chemotherapy. TT have shown an acceptable profile for toxicity and safety in animal studies and early clinical trials have demonstrated a therapeutic response. This review summarizes the characteristics of DT-based TT, the animal studies in malignant brain tumors and early clinical trial results. Obstacles to the successful treatment of brain tumors include poor penetration into tumor, the immune response to DT and cancer heterogeneity. PMID:23695514

  9. [Shiga toxin and tetanus toxin as a potential biologic weapon].

    PubMed

    Toczyska, Izabela; Płusa, Tadeusz

    2015-09-01

    Toxins produced by the bacteria are of particular interest as potential cargo combat possible for use in a terrorist attack or war. Shiga toxin is usually produced by shiga toxigenic strains of Escherichia coli (STEC - shigatoxigenic Escherichia coli). To infection occurs mostly after eating contaminated beef. Clinical syndromes associated with Shiga toxin diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS - hemolytic uremic syndrome) or thrombotic thrombocytopenic purpura. Treatment is symptomatic. In HUS, in which mortality during an epidemic reaches 20%, extending the kidney injury dialysis may be necessary. Exposure to tetanus toxin produced by Clostridium tetani, resulting in the most generalized tetanus, characterized by increased muscle tension and painful contractions of individual muscle groups. In the treatment beyond symptomatic behavior (among others spasticity medications, anticonvulsants, muscle relaxants) is used tetanus antitoxin and antibiotics (metronidazole choice). A common complication is acute respiratory failure - then it is necessary to implement mechanical ventilation. PMID:26449578

  10. TcdC does not significantly repress toxin expression in Clostridium difficile 630ΔErm.

    PubMed

    Bakker, Dennis; Smits, Wiep Klaas; Kuijper, Ed J; Corver, Jeroen

    2012-01-01

    In the past decade, Clostridium difficile has emerged as an important gut pathogen. Symptoms of C. difficile infection range from mild diarrhea to pseudomembranous colitis, sometimes resulting in colectomy or death. The main virulence factors of C. difficile are toxin A and toxin B. Besides the genes encoding these toxins (tcdA and tcdB), the pathogenicity locus (PaLoc) also contains genes encoding a sigma factor (tcdR) and a putative anti-sigma factor (tcdC). The important role of TcdR as a sigma factor for toxin expression is undisputed, whereas the role of TcdC as an anti-sigma factor, inhibiting toxin expression, is currently the subject of debate. To clarify the role of TcdC in toxin expression, we generated an isogenic ClosTron-based mutant of tcdC in Clostridium difficile strain 630Δ Erm (CT::tcdC) and determined the transcription levels of the PaLoc genes and the expression levels of the toxins in the wild type strain and the tcdC mutant strain. We found only minor differences in transcription levels of the PaLoc genes between the wild type and CT::tcdC strains and total toxin levels did not significantly differ either. These results suggest that in C. difficile 630Δerm TcdC is not a major regulator of toxin expression under the conditions tested. PMID:22912837

  11. The effect of stem cell from human exfoliated deciduous teeth on T lymphocyte proliferation

    PubMed Central

    Alipour, Razieh; Adib, Minoo; Hashemi-Beni, Batool; Sadeghi, Farzaneh

    2014-01-01

    Background: Mesenchymal stem cells (MSC), a specific type of adult tissue stem cell; have the immunosuppressive effects that make them valuable targets for regenerative medicine and treatment of many human illnesses. Hence, MSC have been the subject of numerous studies. The classical source of MSC is adult bone marrow (BM). Due to many shortcomings of harvesting MSC from BM, finding the alternative sources for MSC is an urgent. Stem cells from human exfoliated deciduous teeth (SHED) are relative new MSC populations that fulfill these criteria but their potential immunosuppressive effect has not been studied enough yet. Thus, in this work the effect of SHED on the proliferation of in vitro activated T lymphocytes were explored. Materials and Methods: In this study, both mitogen and alloantigen activated T cells were cultured in the presence of different numbers of SHED. In some co-cultures, activated T cells were in direct contact to MSCs and in other co-cultures; they were separated from SHED by a permeable membrane. In all co-cultures, the proliferation of T cells was measured by ELISA Bromodeoxyuridine proliferation assay. Results: In general, our results showed that SHED significantly suppress the proliferation of activated T cells in a dose-dependent manner. Moreover, the suppression was slightly stronger when MSCs were in physical contact to activated T cells. Conclusion: This study showed that SHED likewise other MSC populations can suppress the activation of T lymphocytes, which can be used instead of BM derived MSCs in many investigational and clinical applications. PMID:25337532

  12. Nonlinear Saturable Absorption of Liquid-Exfoliated Molybdenum/Tungsten Ditelluride Nanosheets.

    PubMed

    Mao, Dong; Du, Bobo; Yang, Dexing; Zhang, Shengli; Wang, Yadong; Zhang, Wending; She, Xiaoyang; Cheng, Huachao; Zeng, Haibo; Zhao, Jianlin

    2016-03-01

    Molybdenum disulfide (MoS2 ) and tungsten disulfide (WS2 ), two representative transition metal dichalcogenide materials, have captured tremendous interest for their unique electronic, optical, and chemical properties. Compared with MoS2 and WS2 , molybdenum ditelluride (MoTe2 ) and tungsten ditelluride (WTe2 ) possess similar lattice structures while having smaller bandgaps (less than 1 eV), which is particularly interesting for applications in the near-infrared wavelength regime. Here, few-layer MoTe2 /WTe2 nanosheets are fabricated by a liquid exfoliation method using sodium deoxycholate bile salt as surfactant, and the nonlinear optical properties of the nanosheets are investigated. The results demonstrate that MoTe2 /WTe2 nanosheets exhibit nonlinear saturable absorption property at 1.55 μm. Soliton mode-locking operations are realized separately in erbium-doped fiber lasers utilizing two types of MoTe2 /WTe2 -based saturable absorbers, one of which is prepared by depositing the nanosheets on side polished fibers, while the other is fabricated by mixing the nanosheets with polyvinyl alcohol and then evaporating them on substrates. Numerous applications may benefit from the nonlinear saturable absorption features of MoTe2 /WTe2 nanosheets, such as visible/near-infrared pulsed laser, materials processing, optical sensors, and modulators. PMID:26800122

  13. The synergistic necrohemorrhagic action of Clostridium perfringens perfringolysin and alpha toxin in the bovine intestine and against bovine endothelial cells

    PubMed Central

    2013-01-01

    Bovine necrohemorrhagic enteritis is a major cause of mortality in veal calves. Clostridium perfringens is considered as the causative agent, but there has been controversy on the toxins responsible for the disease. Recently, it has been demonstrated that a variety of C. perfringens type A strains can induce necrohemorrhagic lesions in a calf intestinal loop assay. These results put forward alpha toxin and perfringolysin as potential causative toxins, since both are produced by all C. perfringens type A strains. The importance of perfringolysin in the pathogenesis of bovine necrohemorrhagic enteritis has not been studied before. Therefore, the objective of the current study was to evaluate the role of perfringolysin in the development of necrohemorrhagic enteritis lesions in calves and its synergism with alpha toxin. A perfringolysin-deficient mutant, an alpha toxin-deficient mutant and a perfringolysin alpha toxin double mutant were less able to induce necrosis in a calf intestinal loop assay as compared to the wild-type strain. Only complementation with both toxins could restore the activity to that of the wild-type. In addition, perfringolysin and alpha toxin had a synergistic cytotoxic effect on bovine endothelial cells. This endothelial cell damage potentially explains why capillary hemorrhages are an initial step in the development of bovine necrohemorrhagic enteritis. Taken together, our results show that perfringolysin acts synergistically with alpha toxin in the development of necrohemorrhagic enteritis in a calf intestinal loop model and we hypothesize that both toxins act by targeting the endothelial cells. PMID:23782465