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Ghosh S, Roy RS, Nandi PK. Unveiling the theoretical aspects of superelectrophilic activation in an inverse demand Diels-Alder reaction. J Mol Model 2023; 29:89. [PMID: 36877401 DOI: 10.1007/s00894-023-05495-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 02/27/2023] [Indexed: 03/07/2023]
Abstract
The present computational study using B3LYP functional and 6-31+G(d) basis set has been accomplished to investigate the mechanism of the inverse demand Diels-Alder reaction between pyridyl imine and propene. The highly charged dicationic superelectrophilic diene with exceptionally low-lying LUMO makes the cycloaddition reaction with propene more favorable by significantly lowering the activation energy. The Wiberg bond indices are calculated in accordance with the formation and breaking processes of bonds. The synchronicity concept is also utilized to explain the global nature of the reaction. A potential outcome of this investigation is the utilization of propene as a C2 building block in the industry.
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Affiliation(s)
- Subhadip Ghosh
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103, India
| | - Ria Sinha Roy
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Prasanta K Nandi
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103, India.
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Sinha Roy R, Ghosh A, Banerjee S, Ghosh S, Das AK. New kind of electride sandwich complexes based on the cyclooctatetraene ligand M 12(η 8-C 8H 8) 2M 22 (M 1 = Na, K and M 2 = Ca, Mg): a theoretical study. Phys Chem Chem Phys 2023; 25:4710-4723. [PMID: 36661858 DOI: 10.1039/d2cp04127h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the present study, the electronic structures of a series of binuclear sandwich complexes based on the cyclooctatetraene ligand M12(η8-C8H8)2M22 (M1 = Na, K and M2 = Ca, Mg) are studied theoretically. Each cyclooctatetraene ligand binds with the metal in the η8 binding mode. The M2-M2 bond length agrees well with the reported bimetallic covalent Ca2 and Mg2 bond lengths. The Wiberg bond index (WBI) also indicates the presence of covalent M2-M2 bonds, which gives additional stability to the complex. A non-nuclear attractor (NNA) is found in-between the M2-M2 bond and the negative Laplacian of the electron density is found at the NNA. Noncovalent interaction (NCI) plot shows that electron density is localized at the M2-M2 bond. Based on the performed analysis, we have concluded that the designed sandwich complexes are electrides. We herein report, for the first time, the electride sandwich complexes of the cyclooctatetraene ligand. Due to the presence of a diffuse electron system, the electride complexes exhibit higher values of the static second hyperpolarizability within the range of 2.6 × 105 to 1.4 × 106 a.u. Among the studied complexes, M12(η8-C8H8)2Ca2 exhibit a higher value of static second hyperpolarizability.
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Affiliation(s)
- Ria Sinha Roy
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Avik Ghosh
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Soumadip Banerjee
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Suniti Ghosh
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Abhijit K Das
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Ghosh A, Banerjee S, Sarkar S, Debnath T, Ash T, Roy RS, Das AK. Energetics and Spectroscopic Properties of Low‐lying CaC
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Isomers: An Astrochemical Perspective. ChemistrySelect 2022. [DOI: 10.1002/slct.202200763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Avik Ghosh
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Soumadip Banerjee
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Subhendu Sarkar
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Tanay Debnath
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Tamalika Ash
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Ria Sinha Roy
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Abhijit K. Das
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
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Roy RS, Ghosh S, Hatua K, Nandi PK. Superalkali-doped borazine and lithiated borazine complexes: diffuse excess electron and large first-hyperpolarizability. J Mol Model 2021; 27:74. [PMID: 33547503 DOI: 10.1007/s00894-021-04688-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/20/2021] [Indexed: 11/26/2022]
Abstract
A number of superalkali (M3O / M3S; M = Li, Na, K)-doped borazine and hexalithio borazine complexes are considered for the theoretical study of their electronic structure and quadratic polarizability. Electron-rich O/S atom of superalkali species remains very close to one boron atom of the ring through non-covalent interaction. The first-hyperpolarizability increases rather significantly upon superalkali doping. The chosen complexes possess diffuse excess electron which is located on the superpalkali moiety of borazine complexes and at the ring site of lithiated borazines. First-hyperpolarizability of M3O(S)@B3N3Li6 complexes are significantly larger than that of the corresponding M3O(S)@B3N3H6 complexes. The magnitude of first-hyperpolarizability of Li3S@B3N3Li6 is larger than that of Li3S@B3N3H6 by about three orders of magnitude.
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Affiliation(s)
- Ria Sinha Roy
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India
| | - Subhadip Ghosh
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India
| | - Kaushik Hatua
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India
| | - Prasanta K Nandi
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India.
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Roy RS, Nandi PK. Electronic structure and large second-order non-linear optical property of COT derivatives - a theoretical exploration. Phys Chem Chem Phys 2018; 20:18744-18755. [PMID: 29961775 DOI: 10.1039/c8cp00163d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A new strategy to design new molecules based on a fused hydrocarbon ring system comprising a COT ring and two 5-membered rings has been proposed for the study of second order NLO properties. The four charge transferring groups -NR2 (R = H, Li, Na and K) in conjunction with a sufficient number of electron withdrawing groups lead to significant variation of structural parameters and polarity. The charge transfer characteristics can be strongly modulated by introducing calcium metal atoms at suitable sites. Ca metal atoms end-capping the nitrogen ends of two adjacent -CN groups lead to electride character while a Ca metal atom bonded directly to the COT ring leads to greater charge transfer. The size of the alkali metal atom has been found to have a dramatic effect on the enhancement of first hyperpolarizability. The most significant electronic asymmetry induced by the larger potassium metal atom strongly enhances the magnitude of first hyperpolarizability. The variation of first hyperpolarizability has been satisfactorily explained in terms of TD-CAMB3LYP calculated spectroscopic parameters in light of the two-state model.
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Affiliation(s)
- Ria Sinha Roy
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711 103, India.
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Mondal A, Hatua K, Roy RS, Nandi PK. Successive lithiation of acetylene, ethylene and benzene: a comprehensive computational study of large static second hyperpolarizability. Phys Chem Chem Phys 2018; 19:4768-4777. [PMID: 28133649 DOI: 10.1039/c6cp07845a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
This work is a revisit of the study of the electron correlation effect of lithium substitution on the second hyperpolarizability (106 a.u.) of acetylene, ethylene and benzene. The large quenching of mean second hyperpolarizability has been addressed by CCSD calculations. The inclusion of triple excitation in the MP4 method generally overestimates second hyperpolarizability in comparison to the MP4SDQ method. The present CCSD γav value of C6Li6: 405 × 104 a.u. obtained with a relatively larger basis set established the earlier prediction of Sadlej et al. [Phys. Chem. Phys. Chem., 2000, 2, 3393-3399] where degenerate non-dipolar transitions in low lying excited states play the crucial role. The successive lithiation results in gradual red shifting of transition energy leading to significant enhancement of second hyperpolarizability. Most of the chosen DFT functionals predict the correct qualitative trend of second hyperpolarizability. The quantitatively different results may be attributed to the case when the ground state wave function cannot be approximated by a single SD.
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Affiliation(s)
- Avijit Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah-711103, India.
| | - Kaushik Hatua
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah-711103, India.
| | - Ria Sinha Roy
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah-711103, India.
| | - Prasanta K Nandi
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah-711103, India.
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Roy RS, Mondal A, Nandi PK. Erratum to: First hyperpolarizability of cyclooctatetraene modulated by alkali and alkaline earth metals. J Mol Model 2017; 23:303. [DOI: 10.1007/s00894-017-3466-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Roy RS, Mondal A, Nandi PK. First hyperpolarizability of cyclooctatetraene modulated by alkali and alkaline earth metals. J Mol Model 2017; 23:93. [PMID: 28243890 DOI: 10.1007/s00894-017-3273-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/06/2017] [Indexed: 11/28/2022]
Abstract
In the present investigation, the first hyperpolarizability of alkali and alkaline earth metal derivatives of cyclooctatetraene (COT) has been calculated using BHHLYP and CAM-B3LYP functional for 6-311++G(d,p), 6-311++G(3df,3pd), and aug-pc 2 basis sets. Introduction of Na/K atoms at the axial position of COT and Li, Na, K/Be, Mg, Ca metal atoms and cyanide groups at the equatorial sites leads to lager enhancement of first hyperpolarizability. The ring charge density can account for the variation of first hyperpolarizability. The two state model has been invoked to explain the variation of first hyperpolarizability.
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Affiliation(s)
- Ria Sinha Roy
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India
| | - Avijit Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India
| | - Prasanta K Nandi
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711 103, India.
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Abstract
Modulation of first hyperpolarizability on varying structure of the bridge.
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Affiliation(s)
- Ria Sinha Roy
- Department of Chemistry
- Indian Institute of Engineering Science and Technology
- Howrah 711 103
- India
| | - Prasanta K. Nandi
- Department of Chemistry
- Indian Institute of Engineering Science and Technology
- Howrah 711 103
- India
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Abstract
This review briefly surveys the conformational properties of guest omega-amino acid residues when incorporated into host alpha-peptide sequences. The results presented focus primarily on the use of beta- and gamma-residues in alphaomega sequences. The insertion of additional methylene groups into peptide backbones enhances the range of accessible conformations, introducing additional torsional variables. A nomenclature system, which permits ready comparisons between alpha-peptides and hybrid sequences, is defined. Crystal structure determination of hybrid peptides, which adopt helical and beta-hairpin conformations permits the characterization of backbone conformational parameters for beta- and gamma-residues inserted into regular alpha-polypeptide structures. Substituted beta- and gamma-residues are more limited in the range of accessible conformation than their unsubstituted counterparts. The achiral beta,beta-disubstituted gamma-amino acid, gabapentin, is an example of a stereochemically constrained residue in which the torsion angles about the Cbeta-Cgamma (theta1) and Calpha-Cbeta (theta2) bonds are restricted to the gauche conformation. Hybrid sequences permit the design of novel hydrogen bonded rings in peptide structures.
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Affiliation(s)
- R S Roy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Abstract
BACKGROUND The Escherichia coli peptide antibiotic microcin B17 (MccB17) contains thiazole and oxazole heterocycles derived from a distributive yet directional cyclization of cysteines and serines in the McbA precursor catalyzed by MccB17 synthetase. Whether the formation of upstream rings potentiates downstream heterocyclization has not been previously determined. RESULTS McbA fragments (46-61 residues) containing glycine substitutions or homocysteine at select upstream cysteine or serine sites were assembled using expressed protein ligation (EPL). Most of these substrates were only partially cyclized by MccB17 synthetase, in contrast to the efficient processing of wild-type McbA(1-61). Homocysteine was not processed to the six-membered heterocycle. CONCLUSIONS The formation of upstream rings in McbA potentiates the cyclization of carboxy-terminal cysteines and serines, probably by selecting against unfavorable substrate conformations. EPL allows structure-function analysis including unnatural amino acid placements to probe the regiospecificity and chemoselectivity of post-translational heterocyclization during antibiotic maturation.
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Affiliation(s)
- R S Roy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Milne JC, Roy RS, Eliot AC, Kelleher NL, Wokhlu A, Nickels B, Walsh CT. Cofactor requirements and reconstitution of microcin B17 synthetase: a multienzyme complex that catalyzes the formation of oxazoles and thiazoles in the antibiotic microcin B17. Biochemistry 1999; 38:4768-81. [PMID: 10200165 DOI: 10.1021/bi982975q] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the maturation of the Escherichia coli antibiotic Microcin B17 (MccB17), the McbA prepro-antibiotic is modified post-translationally by the multimeric microcin synthetase complex (composed of the McbB, -C, and -D proteins), which cyclizes four cysteines and four serines to thiazoles and oxazoles, respectively. Herein, we report the purification of individual subunits of MccB17 synthetase as fusions to maltose binding protein (MBP), and the in vitro reconstitution of heterocyclization activity. Preliminary characterization of each subunit reveals McbB to be a zinc-containing protein that may catalyze the initial cyclodehydration step, and McbC to contain flavin, consistent with an anticipated role for a dehydrogenase. We have previously demonstrated that McbD is a regulated ATPase/GTPase that may function as a conformational switch. Photolabeling experiments with the McbA propeptide now identify McbD as the initial site of substrate recognition. Heterocyclization activity was reconstituted only by combining all three subunits, demonstrating that each protein is required for heterocycle formation. Titration assays indicate that the subunits bind to each other with at least micromolar affinities, although McbD affords activity only after the MBP tag is proteolytically removed. Subunit competition assays with an McbDD147A mutant, which yields a catalytically deficient synthetase in vivo, show it to be defective in complex formation, whereas the McbBC181A/C184A double mutant, which is also inactive, competitively inhibits reconstitution by native McbB. Addition of the HtpG chaperone (originally shown to copurify with MccB17 synthetase), does not stimulate synthetase reconstitution or heterocyclization activity in vitro. A model for synthetase activity is proposed.
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Affiliation(s)
- J C Milne
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Affiliation(s)
- R S Roy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Ben Abdelmoumen B, Roy RS, Brousseau R. Cloning of Mycoplasma synoviae genes encoding specific antigens and their use as species-specific DNA probes. J Vet Diagn Invest 1999; 11:162-9. [PMID: 10098689 DOI: 10.1177/104063879901100210] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A genomic library of Mycoplasma synoviae (MS) was generated by using bacteriophage lambda gt11 as a cloning and expression vector. Identification of recombinant clones highly specific to MS was achieved by screening the library for expression of MS proteins with polyclonal antiserum that had been preadsorbed with 6 heterologous avian mycoplasma species antigens. Expression of the recombinant clones in Escherichia coli followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the total cell lysates and immunoblot yielded a predominant reactive fusion protein of 165 kD. Two clones (MS2/28 and MS2/12) that yielded inserts of different size were selected. The 2 MS DNA inserts were subcloned in a plasmid vector, labeled with digoxigenin, and used as probes for the specific recognition of several MS strains. A high degree of conservation was demonstrated for the MS2/12 and MS2/28 genes in tested MS strains. In addition, neither DNA fragment recognized any other avian mycoplasma species (M. gallisepticum, M. meleagridis, M. gallinarum, M. iners, M. anatis, and M. iowae), thus indicating their high specificity to MS. The sensitivity of the slot blot hybridization method using digoxigenin-labeled MS2/12 and MS2/28 probes for direct detection of MS from broth cultures of field isolates was 10(5) colony-forming units/ml. These results demonstrate the effectiveness of adsorbed antisera for the isolation of species-specific mycoplasma DNA and the potential for its use as probes for the specific and direct detection of MS from broth cultures of field isolates.
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Affiliation(s)
- B Ben Abdelmoumen
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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Abstract
BACKGROUND The Escherichia coli peptide antibiotic microcin B17 (MccB17) contains four oxazole and four thiazole rings introduced post-translationally in the 69 amino acid McbA gene product, an MccB17 precursor, by the microcin B,C,D enzyme complex. Both monocyclic and 4,2-bis-heterocyclic moieties are generated. The enzymatic cyclization involves 14 of the last 43 amino acids of McbA and requires the presence of the first 26 amino acids that function as a specificity-conferring propeptide. RESULTS We have constructed maltose-binding protein (MBP)-McbA1-46 fusion proteins and have mutagenized the Gly39-Ser40-Cys41 (GSC) wild-type sequence to assess the regioselectivity and chemoselectivity of MccB17-synthetase-mediated heterocycle formation at the first two loci, residues 40 and 41 of McbA. Four single-site and four double-site substrates showed substantial differences in turnover as assessed by western assays, UV-visible spectroscopy and mass spectrometry. Cysteine-derived thiazoles form at a greater rate than serine-derived oxazoles. Formation of bis-heterocycles is sensitive both to composition and sequence context. CONCLUSIONS The E. coli McbB,C,D MccB17 synthetase is the first peptide heterocyclization enzyme to be characterized. This study reveals substantial regioselectivity and chemoselectivity (thiazole > oxazole) at the most amino-terminal bis-heterocyclization site of McbA. The heterocyclization of GSS and GCC mutants of McbA1-46 by MccB17 synthetase demonstrates that the complex can efficiently generate tandem bis-oxazoles and bis-thiazoles, moieties not found in MccB17 but present in natural products such as hennoxazole and bleomycin. The observations suggest a common enzymatic mechanism for the formation of peptide-derived heterocyclic natural products.
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Affiliation(s)
- P J Belshaw
- Department of Biological Chemistry and Molecular Pharmacology Harvard Medical School Boston, MA 02115, USA
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Roy RS, Kim S, Baleja JD, Walsh CT. Role of the microcin B17 propeptide in substrate recognition: solution structure and mutational analysis of McbA1-26. Chem Biol 1998; 5:217-28. [PMID: 9545435 DOI: 10.1016/s1074-5521(98)90635-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The peptide antibiotic microcin B17 (MccB17) contains oxazole and thiazole heterocycles formed by the post-translational modification of four cysteine and four serine residues. An amino-terminal propeptide targets the 69 amino acid precursor of MccB17 (preproMccB17) to the heterocyclization enzyme MccB17 synthetase. The mode of synthetase recognition has been unclear, because there has been limited structural information available on the MccB17 propeptide to date. RESULTS The solution structure of the MccB17 propeptide (McbA1-26), determined using nuclear magnetic resonance, reveals that McbA1-26 is an amphipathic alpha helix. Mutational analysis of 13 propeptide residues showed that Phe8 and Leu12 are essential residues for MccB17 synthetase recognition. A domain of the propeptide was putatively identified as the region that interacts with the synthetase. CONCLUSIONS MccB17 synthetase recognizes key hydrophobic residues within a helical propeptide, allowing the selective heterocyclization of downstream cysteine and serine residues in preproMccB17. The determination of the solution structure of the propeptide should facilitate the investigation of other functions of the propeptide, including a potential role in antibiotic secretion.
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Affiliation(s)
- R S Roy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Abstract
The transaminase activity of two new semisynthetic RNase-S proteins incorporating a pyridoxamine moiety at the active site has been evaluated. A chemically competent derivative of pyridoxamine phosphate was incorporated into the C-peptide fragments of these non-covalent protein complexes in the form of an unnatural coenzyme-amino acid chimera, 'Pam'. The chimeric Pam residue integrates the heterocyclic functionality of pyridoxamine phosphate into the side chain of an alpha-amino acid and was introduced instead of Phe8 into the C-peptide sequence via standard solid phase methodology. The two semisynthetic Pam-RNase constructs were designed to probe whether the native ribonuclease catalytic machinery could be enlisted to modulate a pyridoxamine-dependent transamination reaction. Both RNase complexes, H1SP and S1SP, exhibited modest rate enhancements in the Cu(II)-assisted transamination of pyruvate to alanine under single turnover conditions, relative to 5'-deoxypyridoxamine and the uncomplexed C-peptide fragments. Furthermore, multiple turnovers of substrates were achieved in the presence of added L-phenylalanine due to recycling of the pyridoxamine moiety. The modest chiral inductions observed in the catalytic production of alanine and the differences in reactivity between the two proteins could be rationalized by the participation of a general base (His12) in complex H1SP, and by the increased tolerance for large amino acid substrates by complex S1SP, which contains serine at this position. The pyridoxamine-amino acid chimera will be useful in the future for examining the coenzyme structure/ function relationships in a native-like peptidyl architecture.
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Affiliation(s)
- R S Roy
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA
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Roy RS. Low back pain. Help is available. N C Med J 1996; 57:225-8. [PMID: 8763910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Ben Abdelmoumen B, Roy RS. Antigenic relatedness between seven avian mycoplasma species as revealed by western blot analysis. Avian Dis 1995; 39:250-62. [PMID: 7677645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cross-reactivities among seven avian mycoplasma species (Mycoplasma gallisepticum, M. synoviae, M. meleagridis, M. iowae, M. anatis, M. gallinarum, and M. iners) were examined using rabbit polyclonal antisera and two monoclonal antibodies (MAbs) against M. pneumoniae: Myc-9 and Myc-4. The major antigens and cross-reacting antigens of the seven mycoplasma species were demonstrated by immunoblotting assay using homologous and heterologous antisera. Two-way cross-reacting antigens of MS and MG, with apparent molecular weights of 44,000 and 36,000, were identified. Additionally, the 36,000 protein of MG was recognized by all of the heterologous antisera. A large number of cross-reactivities, which have been never investigated before, were shown between M. meleagridis and M. synoviae, between M. meleagridis and M. gallinarum, between M. meleagridis and M. iners, and between M. gallinarum and M. iners. All of the cross-reactions existing between the majority of the above species were considerably reduced or eliminated by adsorbing the polyclonal antisera with a pool of heterologous antigens. Two MAbs against a M. pneumoniae protein of a molecular weight of 150,000 were also able to recognize several avian mycoplasma epitopes, of which two common epitopes with molecular weights of 44,000 and 42,000 were present in most of the seven mycoplasma species.
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Affiliation(s)
- B Ben Abdelmoumen
- Départemente de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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Abdelmoumen BB, Roy RS. An enzyme-linked immunosorbent assay for detection of avian mycoplasmas in culture. Avian Dis 1995; 39:85-93. [PMID: 7794195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
An antigen-capture enzyme-linked immunosorbent assay (ELISA), using monoclonal antibody (Myc-9) against Mycoplasma pneumoniae, was developed for the detection of M. gallisepticum, M. synoviae, M. meleagridis, M. iowae, M. anatis, M. iners, and M. gallinarum antigens in cultures. ELISA plates were coated with Myc-9 and reacted with the different avian mycoplasma antigens, which were detected with adsorbed polyclonal anti-mycoplasma serum followed by anti-rabbit enzyme-labeled conjugate antiserum. Nonspecific reactions and cross-reactivity were eliminated by adsorbing polyclonal antisera with a pool of heterologous antigens, and a high degree of sensitivity was obtained by both antigen enrichment and treatment with the detergent N-octyl glucoside. Under these conditions, the test detected less than 10 colony-forming units/ml. This antigen-capture ELISA appears to be a highly specific, sensitive, reproducible tool and efficient in the diagnosis of mycoplasma infection.
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Affiliation(s)
- B B Abdelmoumen
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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21
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Abstract
Fourteen monoclonal antibodies (MAbs) against "Quebec" strain (Q17) of bovine rotavirus were isolated and characterized. Four were specific for viral protein Vp7 and ten were specific for viral protein Vp6. Five different isotypes were represented by this group of antibodies. All of the anti-Vp6 and none of the anti-Vp7 antibodies were sensitive to the effects of periodate on their antigen. The antibodies could be separated into three groups based on their relative resistance to the dissociation of their antigen-antibody complex by thiocyanate. The MAbs cross-reacted with the proteins of porcine and human rotaviruses both by immunoprecipitation and immunoblot analyses. These techniques revealed the differences in Mw of the viral proteins from different serotypes.
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Affiliation(s)
- E Cornaglia
- Virology Section, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Que., Canada
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22
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Archambault D, Morin G, Elazhary Y, Roy RS. Study of virus excretion in feces of diarrheic and asymptomatic calves infected with rotavirus. Zentralbl Veterinarmed B 1990; 37:73-6. [PMID: 2161171 DOI: 10.1111/j.1439-0450.1990.tb01028.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Infection of calves by rotavirus could lead to diarrhea or subclinical disease. Therein, kinetic of viral excretion from a group of asymptomatic calves, previously exposed to a virulent strain of rotavirus, is compared to that of a group the calves of which had diarrhea associated with rotavirus infection. As determined by an enzyme-linked immunosorbent assay (ELISA), duration of rotavirus shedding in feces and maximum yield of virus antigen were similar within the two groups of calves. Rotaviruses isolated from the two above groups of animals were antigenically related as shown by neutralization tests, and showed a similar RNA electrophoretic profile. In conclusion, it is likely that both asymptomatic and diarrheic calves infected by rotavirus are equally a major source of contamination to contact healthy calves.
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Affiliation(s)
- D Archambault
- Faculty of Veterinary Medicine, Department of Pathology and Microbiology, St-Hyacinthe, Quebec Canada
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23
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Archambault D, Morin G, Elazhary Y, Roy RS, Joncas JH. Immune response of pregnant heifers and cows to bovine rotavirus inoculation and passive protection to rotavirus infection in newborn calves fed colostral antibodies or colostral lymphocytes. Am J Vet Res 1988; 49:1084-91. [PMID: 2844107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The efficacy of an adjuvanted bovine rotavirus vaccine in pregnant cattle (15 heifers and 2 cows) was studied. Each of 4 animals was inoculated IM at 8, 5, and 2 weeks before parturition with a water-in-oil emulsion containing live purified bovine rotavirus, mineral oil, and a mannide oleate compound. Four other animals were treated identically, except that muramyl dipeptide was added to the virus preparation. Five additional animals were inoculated orally at the same time intervals with adjuvant-free viral suspension, and 4 other pregnant animals inoculated only with buffer served as uninoculated controls. Kinetic studies of the specific immune responses were determined by quantification of the rotavirus-neutralizing antibodies and by a rotavirus lymphocyte stimulation test in vitro. Results showed that only the emulsions induced marked enhancement of rotavirus antibody titers in the serum, colostrum, and milk of inoculated cows. Colostral and milk lymphocytes isolated from these cows had a positive in vitro proliferative response to rotavirus stimulation, which lasted at least 21 days after parturition. The values of the stimulation index obtained with the colostral/milk lymphocytes were higher than those of the blood lymphocytes, reflecting increased lymphocyte activity in the colostrum/milk. However, addition of muramyl dipeptide to the emulsion preparation did not exert any potentiating effect on the immune response to rotavirus. Calves fed for the first 5 days after birth with a rotavirus-immune cell-free colostrum supplement were protected from a rotavirus challenge exposure on the third day after birth. Virus was not detectable in their feces.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D Archambault
- Faculty of Veterinary Medicine, Department of Pathology and Microbiology, St-Hyacinthe, Quebec, Canada
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24
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Archambault D, Morin G, Elazhary Y, Joncas JH, Roy RS. Standardization and kinetics of in vitro bovine blood lymphocyte stimulation with bovine rotavirus. Comp Immunol Microbiol Infect Dis 1988; 11:11-20. [PMID: 2838218 PMCID: PMC7124774 DOI: 10.1016/0147-9571(88)90003-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/1987] [Indexed: 01/02/2023]
Abstract
Two groups of 3-month old calves were immunized intramuscularly with attenuated bovine rotavirus and boosted 21 and 42 days later. The first group of three calves were vaccinated with live virus emulsified with incomplete Freund's adjuvant (IFA) and the second group was immunized with live virus suspended in phosphate buffered saline (PBS). Three other calves, serving as controls, were inoculated with PBS emulsified with IFA. The specific cell-mediated and antibody responses of the animals were studied. Preliminary analysis of in vitro peripheral blood lymphocyte transformation to bovine rotavirus determined optimal conditions as: 96 h culture period, 5 X 10(5) cells per culture in RPMI 1640 medium containing 10% heat-inactivated bovine fetal serum and the use of inactivated virus in the cell culture at a concentration of 5 X 10(6) median tissue culture infective dose before inactivation. Specific blastic stimulation was observed on calves immunized with the rotavirus emulsified with IFA after the second and third vaccine inoculation with stimulation index values varying from 2.00 to 5.73. Serum neutralizing antibody titers of 1/25,600 were also induced in the same calves. Calves immunized with rotavirus-PBS suspension developed a mean antibody titer of 1/1,600, but showed no specific lymphocyte stimulation. No increase in specific immune responses was detected in the control animals.
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Affiliation(s)
- D Archambault
- Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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25
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Abstract
Enterovirus-like particles from feces of calves are a frequent source of contamination of bovine rotavirus isolates. A study of plaque formation using BSC-1 cells indicated differences in behaviour of the viruses which could be used for differentiation the purification. The enterovirus-like particles produced well-defined plaques earlier and reached their optimal size much more rapidly than did the rotavirus. Furthermore, plaques produced by bovine enterovirus-like particles were significantly larger than those of bovine rotavirus. The viral cytopathic effects on the cells within the plaques were also characteristic for each virus.
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26
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Dea S, Archambault D, Elazhary MA, Roy RS. Genomic variations and antigenic relationships among cytopathic rotavirus strains isolated in Quebec dairy herds. Can J Vet Res 1986; 50:126-9. [PMID: 3017524 PMCID: PMC1255174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Twelve isolates of bovine rotavirus, originating from eight dairy herds in Quebec known to have frequent epizootics of diarrhea in young calves in the last five years, were successfully propagated in cell cultures. The 12 isolates produced clear-cut plaques in BSC-1 cells and, except for one isolate, agglutinated human group "O" erythrocytes to an higher titer than bovine erythrocytes. Antisera to each isolate were produced in rabbits and used to study their antigenic relationships. All the isolates shared the group-specific immunofluorescent antigen and were antigenically related as demonstrated by the seroneutralization and hemagglutination-inhibition tests. However, the relationships to the Nebraska rotavirus was quite weak in cases of two Quebec isolates. When the genomes of the various isolates were compared by polyacrylamide gel electrophoresis, at least three different reproducible fractionation patterns could be identified.
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27
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Dea S, Elazhary MA, Roy RS. Distinct serotypes of porcine rotavirus associated with diarrhea in suckling piglets in southern Quebec. Can J Vet Res 1986; 50:130-2. [PMID: 3017525 PMCID: PMC1255175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cytopathic rotavirus strains were isolated in cell cultures from the intestinal contents of diarrheic piglets on Quebec pig farms where repeated outbreaks of enteritis occurred. All the isolates shared the common group antigens of rotaviruses as revealed by immunofluorescence and counterimmunoelectrophoresis. A hemagglutinating activity was demonstrated with human group O, porcine and guinea pig erythrocytes. At least one of the isolates was clearly distinguished from the American prototype of porcine rotavirus (strain OSU) by neutralization and hemagglutination inhibition tests; a third serotype was also suspected. By polyacrylamide gel electrophoresis of RNA, it was not possible to differentiate these isolates.
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28
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Dea S, Begin ME, Archambault D, Elazhary MA, Roy RS. Distinct rotaviruses isolated from asymptomatic calves. Cornell Vet 1985; 75:307-18. [PMID: 2985333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rotaviruses were isolated following cell culture of the intestinal contents of four non-diarrheic calves. The four isolates were serially propagated in MDBK and BSC-1 cells in the presence of trypsin and produced rotavirus particles morphologically similar to those found associated with diarrhea. They were antigenically related to the Nebraska calf rotavirus (Norden strain) as investigated by immunofluorescence. Three isolates could be distinguished from the reference Nebraska rotavirus by their thermal stability and/or their differential responses to intestinal neutralizing antibodies. Two isolates produced on BSC-1 cells plaques significantly different in size from the reference strain, No significant genomic variations were detected among the isolates.
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29
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Archambault D, Roy RS, Dea S, Elazhary MA. Comparative study of bovine rotavirus isolates by plaque assay. Can J Comp Med 1984; 48:286-9. [PMID: 6089982 PMCID: PMC1236062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Rotaviruses were isolated on BSC-1 cells from counterimmunoelectrophoresis and/or electron microscopy positive intestinal contents from two asymptomatic and six diarrheic calves from Quebec. The plaque assay was performed using these lines and agar overlay medium containing trypsin and DEAE-dextran. This assay was used to compare the Quebec isolates to an attenuated American strain (NCDV) and another strain (TH) obtained from France. The NCDV strain produced plaques that were significantly larger than those produced by the TH strain. Three Quebec isolates produced plaques similar in size to TH strain, one isolate was similar to NCDV strain and another isolate produced larger plaques than those of both NCDV and TH strains. The other isolates induced the production of plaques that were not significantly different from those of NCDV or TH strains.
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30
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Bois JM, Roy RS, Guay P. Counterimmunoelectrophoresis for the diagnosis of bovine mycoplasmosis. Am J Vet Res 1984; 45:1020-2. [PMID: 6732006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Counterimmunoelectrophoresis (CIE) procedure has been established for mycoplasma identification from cultures, and the specificity and the sensitivity of this technique were evaluated. Preparations of milk samples and clinical and necropsy specimens were used for the technique. From 171 milk samples, 80 (46.8%) were positive by CIE (73 samples with Mycoplasma bovis and 7 with Mycoplasma arginini) and 77 (45%) were positive by biochemical and growth inhibition tests (70 samples with Mycoplasma bovis and 7 with Mycoplasma arginini). From 36 mycoplasma culture-positive clinical and necropsy specimens, CIE identified 5 different mycoplasma species and from 3 mycoplasma culture-positive specimens, the technique identified coinfection by 2 mycoplasma species. The CIE is a reliable, specific, sensitive, and rapid technique for the diagnosis of mycoplasmosis in the bovine.
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31
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Abstract
Several phenothiazines were found to provide significant protection against loss of tissue creatine phosphokinase caused by the calcium paradox. The concentration of phenothiazine required for protection lies within the range generally attributable to their calmodulin inhibition properties. Moreover, the order of effectiveness in protecting the calcium overloaded myocardium is consistent with their potency as calmodulin inhibitors (trifluoperazine greater than chloropromazine greater than promethazine). The most potent calmodulin inhibitor was shown to dramatically reduce the amount of creatine phosphokinase loss from calcium depleted hearts exposed to buffer containing calcium under anoxic conditions. On the other hand, the drug failed to alter the oxygen-dependent component of the calcium paradox. It also failed to prevent the proteolytic conversion of xanthine dehydrogenase to xanthine oxidase. The possibility that calmodulin activation promotes cellular damage by activating either directly or indirectly specific membrane cellular phospholipases is discussed. Also discussed is the hypothesis that oxygen-dependent damage may be linked to the generation of superoxide anion by the enzyme xanthine oxidase.
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32
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Dea S, Roy RS, Elazhary MA. Virus-like particles, 45 to 65 nm, in intestinal contents of neonatal calves. Can J Comp Med 1983; 47:88-91. [PMID: 6831311 PMCID: PMC1235895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Enveloped virus particles 45 to 65 nm in diameter, tentatively called minicorona virus, were detected by electron microscopy in the intestinal contents of one normal and seven diarrheic calves in Quebec dairy herds. The agent was shown to be antigenically unrelated to the Nebraska calf diarrhea coronavirus and to the bovine viral diarrhea virus by counterimmunoelectrophoresis and fluorescent-antibody techniques. Antibodies against these particles were demonstrated in the serum of affected calves using immunoelectron microscopy. The agent could not be isolated in cell cultures and its possible role as etiological agent in calf diarrhea is still to be determined.
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33
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Abstract
The superoxide radical plays major roles in the neutrophil-medicated acute inflammatory response and in postischemic tissue injury, although the sources and actions of the radical are quite different in these two pathological states. While neutrophils produce superoxide for the primary purpose of aiding in the killing of ingested microbes, a second useful function has evolved. The superoxide released from actively phagocytosing neutrophils serves to attract more neutrophils by reacting with, and activating, a latent chemotactic factor present in plasma. Superoxide dismutase, by preventing the activation of this superoxide-dependent chemotactic factor, exerts potent anti-inflammatory action. During ischemia, energy-starved tissues catabolize ATP to hypoxanthine. Calcium transients in these cells appear to activate a calmodulin regulated protease which attacks the enzyme xanthine dehydrogenase, converting it to a xanthine oxidase capable of superoxide generation. When the tissue is reperfused and reoxygenated, all the necessary components are present (xanthine oxidase, hypoxanthine, and oxygen) to produce a burst of superoxide which results in extensive tissue damage. Ischemic tissues are protected by superoxide dismutase or allupurinol, an inhibitor of xanthine oxidase.
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34
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Dea S, Roy RS, Elazhary MA. Coronavirus-like Particles in the Feces of a Cat with Diarrhea. Can Vet J 1982; 23:153-5. [PMID: 17422139 PMCID: PMC1790106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Coronavirus-like particles were visualized in the feces of a young domestic shorthair female cat with diarrhea. On the surface projections, these particles could be distinguished from the enteric coronavirus-like particles of human, dog, cattle and monkey origin. They appeared morphologically similar to a feline enteric coronavirus recently described by other authors. A precipitin antigen was detected in the cat feces by counterimmunoelectroosmophoresis using a rabbit antibovine coronavirus serum.
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35
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Dea S, Roy RS, Elazhary MA. Antigenic variations among calf diarrhea coronaviruses by immunodiffusion and counterimmunoelectrophoresis. Ann Rech Vet 1982; 13:351-356. [PMID: 6821021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The antigenic relationship among five bovine coronavirus isolates was studied using the counterimmunoelectrophoresis (CIE) and immunodiffusion (ID) techniques. By CIE, two precipitating antigens were observed for each coronavirus isolate. One antigen identified as the "M" coronaviral antigen was found to be common to the five isolates while the second antigen identified as the "m" coronaviral antigen differed between the isolates. Considering the later antigen, the isolates studied were placed in two antigenic groups, members of the same group being indistinguishable for the two antigens. By ID, reactions of partial identity were noted between viruses of the different groups.
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36
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Silim A, El Azhary MA, Roy RS. A simple technique for preparation of chicken-embryo-skin cell cultures. Avian Dis 1982; 26:182-5. [PMID: 6284112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A simple, rapid technique was developed for preparing chicken-embryo-skin cell cultures utilizing trypsinization of the skin of intact 12-day-old chicken embryos. When cell cultures were inoculated with fowl pox virus, those that consisted of at least 80% epithelial cells yielded a higher virus titer than fibroblast cell cultures.
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37
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Elazhary MA, Frechette JL, Silim A, Roy RS. Serological evidence of some bovine viruses in the caribou (Rangifer tarandus caribou) in Quebec. J Wildl Dis 1981; 17:609-12. [PMID: 6121921 DOI: 10.7589/0090-3558-17.4.609] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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38
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El-Azhary MA, Silim A, Roy RS. Interferon, fluorescent antibody, and neutralizing antibody responses in sera of calves inoculated with bovine respiratory syncytial virus. Am J Vet Res 1981; 42:1378-82. [PMID: 6170241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Interferon, fluorescent antibody, and neutralizing antibody responses were studied in sera of 9 calves inoculated with bovine respiratory syncytial virus, in relation to viral shedding and clinical signs of disease. The calves (5.5 to 6.5 weeks of age) were assigned to 3 groups. Group I was inoculated once with the virus, and groups II and III were challenge exposed at postinoculation day (PID) 15 or 37. Serum-neutralizing and indirect fluorescent antibody techniques were used to measure antibody responses. The plaque-inhibition technique, using vesicular stomatitis virus, was applied to measure serum interferon titers. The virus was recovered by inoculation of nasal secretions onto cell cultures. Fluorescent antibody was detected in all calves on PID 3, with maximum titers appearing approximately on PID 10. Low neutralizing antibody was detected in most animals on PID 3, and titers peaked approximately 4.5 weeks after inoculation and then decreased. Interferon titers were high in all calves during the early stage of infection, dropped to undetectable amounts by PID 6, and reappeared in low amounts at least 1 week later. All infected calves manifested clinical signs of disease by PID 4 to 9. Clinical signs of disease were not observed after challenge exposure at PID 15 or 37, and anamnestic responses were not detected. Virus was recovered after challenge exposure at PID 15, but not at PID 37.
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39
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Dea S, Roy RS, Elazhary MA. [Calf coronavirus neonatal diarrhea. A literature review (author's transl)]. Can Vet J 1981; 22:51-8. [PMID: 6269715 PMCID: PMC1789880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Calf coronavirus neonatal diarrhea. A literature reviewThe importance of the calf coronavirus in the etiology of neonatal diarrhea of calves has been reported many times from various countries. A literature review concerning this virus is presented in this paper. A detailed description of the pathogenesis, clinical signs and lesions of the disease, as well as the morphological, physicochemical, biological and antigenic characteristics of the virus are presented. The immunity of the calf against this virus and the principal diagnosis technics are also discussed.
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40
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Elazhary MA, Lamothe P, Silim A, Roy RS. Bovine herpesvirus type 1 in the sperm of a bull from a herd with fertility problems. Can Vet J 1980; 21:336-9. [PMID: 6266630 PMCID: PMC1789830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A herd of 125 Holstein cows manifested fertility problems for two years. The number of services per pregnancy was 2.97, conception rate was 33% after the first service, and the average number of open days was 127. Abortions occurred in four cows over the last 12 months. The herd was not vaccinated against any disease. Natural service by a bull and artificial insemination were used for breeding the cows. Bovine herpesvirus type 1 was demonstrated in sperm heads from the bull by direct and indirect fluorescent antibody techniques, and the virus was isolated on cell cultures. The virus was also isolated from the uterine secretions of some cows and from two aborted fetuses.
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41
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Elazhary MA, Galina M, Roy RS, Fontaine M, Lamothe P. Experimental infection of calves with bovine respiratory syncytial virus (Quebec strain). Can J Comp Med 1980; 44:390-5. [PMID: 7448628 PMCID: PMC1320095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An experiment was designed to evaluate the clinical, haematological, viral and serological aspects of bovine respiratory syncytial virus infection in calves. Eleven calves were inoculated intranasally with bovine respiratory syncytial virus (Quebec strain) in aerosol. Clinical, haemotological and serological responses of the calves and virus shedding were monitored. The experimentally infected animals manifested moderate to severe signs of respiratory disease. The parameters used to evaluate the severity of the disease included ocular discharge, conjunctivitis, lung sounds, nasal discharge, pyrexia and leukopenia. The animals were scored accordingly (scale infected 70.8-148.5, control 22-29.3). Highest disease scores were observed between day 6-9 after infection. Virological and serological assessment demonstrated that the observed clinical picture was due to bovine respiratory syncytial virus infection.
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42
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Elazhary MA, Roy RS, Champlin R, Higgins R, Marsolais G. Bovine respiratory syncytial virus in Quebec: antibody prevalence and disease outbreak. Can J Comp Med 1980; 44:299-303. [PMID: 7000320 PMCID: PMC1320077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The prevalence of antibody to bovine respiratory syncytial virus in Quebec and the role of the virus in a respiratory disease outbreak was investigated. The indirect immunofluorescent, neutralization and haemagglutination inhibition techniques were used to carry out this study. Of the 1,444 adult animals examined 519 (35.9%) had antibody to bovine respiratory syncytial virus. These positive reactors were found in each agricultural region of Quebec. The highest (53.0%) and the lowest (21.8%) prevalence was observed in the sera collected by the laboratories of St. Hyacinthe and Sherbrooke. During a respiratory disease outbreak affecting 77 calves on a farm, bovine respiratory syncytial virus was shown to be associated with infectious bovine rhinotracheitis, bovine parainfluenza type 3, bovine viral diarrhea viruses and bovine adenovirus type 3 as detected by seroconversion. Of the 38 seroconverted animals 14 were seropositive to bovine respiratory syncytial virus.
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43
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Dea S, Elazhary MA, Roy RS. [Influenza viruses in man and animals. A literature review (author's transl)]. Can Vet J 1980; 21:171-8. [PMID: 6159061 PMCID: PMC1789716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Influenza viruses in man and animals. A literature reviewA literature review on the influenza viruses is presented in this paper. A description of the disease in man and domestic animals, as well as general considerations on morphological, physicochemical and antigenic properties of these viruses is given. Emphasis is put on the role of the antigenic changes of these viruses with regard to the epidemiology of the disease, as well as on the possible origin of the pandemic and epidemic strains.
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44
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Dea S, Roy RS, Begin ME. Physicochemical and biological properties of neonatal calf diarrhea coronaviruses isolated in Quebec and comparison with the Nebraska calf coronavirus. Am J Vet Res 1980; 41:23-9. [PMID: 7362122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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45
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Dea S, Roy RS, Begin ME. Bovine coronavirus isolation and cultivation in continuous cell lines. Am J Vet Res 1980; 41:30-8. [PMID: 6767425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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46
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47
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Dea S, Roy RS, Begin ME. Counterimmunoelectroosmophoresis for detection of neonatal calf diarrhea coronavirus: methodology and comparison with electron microscopy. J Clin Microbiol 1979; 10:240-4. [PMID: 229123 PMCID: PMC273137 DOI: 10.1128/jcm.10.2.240-244.1979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A counterimmunoelectroosmophoresis (CIE) technique is described for the detection of calf diarrhea coronavirus antigens in intestinal contents. The antibody reagent was prepared in rabbits against the Nebraska calf diarrhea coronavirus adapted to Vero cells and purified by density gradient centrifugation. The method was applied to intestinal contents of diarrheic and normal calves and compared with electron microscopy (EM). Calf coronavirus antigens were detected in intestinal contents of 44% (21/48) of the diarrheic calves and 24% (4/17) of the normal calves. Two precipitin lines could be observed in the majority of the positive samples. When compared with EM, CIE detected more positive animals. In only two cases (2/20) CIE was negative despite the visualization of coronavirus particles by EM.
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48
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Elazhary MA, Berthiaume L, Roy RS, Alain R, Lagacé A. Morphological and quantitative study of spirochetes in the feces of normal and infected SPF pigs during the incubation period of swine dysentery. Can J Comp Med 1978; 42:302-9. [PMID: 150936 PMCID: PMC1277642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spirochetes found in feces of normal and infected pigs during the eight days preceding the onset of the clinical signs of swine dysentery have been studied using electron and phase contrast microscopy. According to their dimensions, diameter, length and pitch, three morphological groups have been described: small, intermediate and large spirochetes. On the basis of their axial filaments arrangement, eight types have been observed. Compared to the control pigs, there was no increase in the total number of spirochetes in infected pigs, except at day 6 before the onset of clinical signs. However, infected pigs have shown a wide spectrum of different morphological types of spirochetes in comparison to control, uninfected pigs, which showed only the type "1-2-1" spirochete of axial filaments arrangement. This last type was predominant in infected swine during the entire incubation period as compared to other spirochete types described.
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Roy RS, Vas SI, Robson HG. Effects of endotoxin on carbohydrate metabolism in inbred mice. Can J Comp Med 1976; 40:434-41. [PMID: 187306 PMCID: PMC1277578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Effects of endotoxin on carbohydrate metabolism were studied in A/HeJ (endotoxin-sensitive) and C3H/HeJ (endotoxin-resistant) inbred mice. A/HeJ mice developed hypoglycemia within two hours after endotoxin injection, yet liver glycogen content did not differ from controls. Similarly treated C3H/HeJ mice did not develop significant hypoglycemia. Administration of glucagon to endotoxin-treated A/HeJ mice failed to elevate their blood glucose concentrations, while endotoxin-treated mice of the same strain did respond to dibutyryl cyclic AMP with a significant elevation of blood glucose. C3H/HeJ mice on the other hand responded to glucagon and dibutyryl cyclic AMP with elevated blood glucose. Endotoxin-treated C3H/HeJ but not A/HeJ mice were able to carry out gluconeogenesis induced by prednisolone, while both inbred strains showed active glycogenesis after administration of an exogenous glucose load. Administration of glucagon resulted in diminished liver glycogen concentrations in A/HeJ endotoxin-treated mice suggesting no impairment of glycogenolysis. The inability of endotoxin-treated A/HeJ mice to respond to glucagon could be due to impairment of gluconeogenesis. Although endotoxin interfered with the capacity of both inbred strains to respond to glucagon administration with elevation of liver cyclic AMP, the effect was significantly more severe in A/HeJ mice. The susceptibility of A/HeJ mice to the lethal effect of endotoxin may be related to the apparent sensitivity of carbohydrate metabolic pathways to disturbance by endotoxin.
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Viviers PL, Elazhary MA, Lagacé A, Roy RS, Tremblay A. [An experimental study on the variation of serum antibody levels relative to the life cycle of the horsefly]. Can J Comp Med 1974; 38:336-40. [PMID: 4277126 PMCID: PMC1319877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The changes of antibody titers in the sera of colts infested naturally or artificially with Gasterophilus have been determined in relation to the life cycle of this arthropod using passive hemagglutination, complement fixation, double diffusion techniques and saline extracts of antigens from the third larval stages of Gasterophilus intestinalis and G. nasalis.In the sera of the infected animals the hemagglutinating antibodies were present at low titers at the third week post-infestation by using somatic extract of G. intestinalis and at the seventh week in case of G. nasalis. At eight weeks post-infestation the antibody titers reached their maximum 1:8192 (G. intestinalis) and 1:4096 (G. nasalis), then dropped at 12 weeks post-infestation. The complement fixing antibodies were present occasionally between the seventh and 11th weeks after infestation. Precipitating antibodies were absent in all sera.
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