The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Daniel C Nelson - One of the best experts on this subject based on the ideXlab platform.
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a chimeolysin with extended spectrum streptococcal host range found by an induced Lysis based rapid screening method
Scientific Reports, 2015Co-Authors: Hang Yang, Sara B Linden, Junping Yu, Jing Wang, Daniel C NelsonAbstract:The increasing emergence of multi-drug resistant streptococci poses a serious threat to public health worldwide. Bacteriophage lysins are promising alternatives to antibiotics; however, their narrow lytic spectrum restricted to closely related species is a central shortcoming to their translational development. Here, we describe an efficient method for rapid screening of engineered chimeric lysins and report a unique “chimeolysin”, ClyR, with robust activity and an extended-spectrum streptococcal host range against most streptococcal species, including S. pyogenes, S. agalactiae, S. dysgalactiae, S. equi, S. mutans, S. pneumoniae, S. suis and S. uberis, as well as representative enterococcal and staphylococcal species (including MRSA and VISA). ClyR is the first lysin that demonstrates activity against the dominant dental caries-causing pathogen as well as the first lysin that kills all four of the bovine mastitis-causing pathogens. This study demonstrates the success of the screening method resulting in a powerful lysin with potential for treating most streptococcal associated infections.
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removal of group b streptococci colonizing the vagina and oropharynx of mice with a bacteriophage lytic enzyme
Antimicrobial Agents and Chemotherapy, 2005Co-Authors: Qi Cheng, Daniel C Nelson, Vincent A FischettiAbstract:Group B streptococci (GBS) are the leading cause of neonatal meningitis and sepsis worldwide. The current treatment strategy is limited to intrapartum antibiotic prophylaxis in pregnant women to prevent early-onset neonatal diseases, but considering the potential for antibiotic resistance, the risk of losing control over the disease is high. To approach this problem, we have developed a bacteriophage (phage) lytic enzyme to remove colonizing GBS. Bacteriophage muralytic enzymes, termed lysins, are highly evolved molecules designed to degrade the cell wall of host bacteria to release phage particles from the bacterial cytoplasm. Several different lysins have been developed to specifically kill bacterial pathogens both on mucosal surfaces and in blood and represent a novel approach to control infection. A lysin cloned from a phage infecting GBS was found to contain two putative catalytic domains and one putative binding domain, which is similar to the domain organization of some staphylococcal phage lysins. The lysin (named PlyGBS) was recombinantly expressed in Escherichia coli, and purified PlyGBS efficiently killed all tested GBS serotypes in vitro. In a mouse model, a single dose of PlyGBS significantly reduced bacterial colonization in both the vagina and oropharynx. As an alternative strategy for intrapartum antibiotic prophylaxis, this approach may be used to reduce vaginal GBS colonization in pregnant women before delivery or to decontaminate newborns, thus reducing the incidence of GBS-associated neonatal meningitis and sepsis.
Hang Yang - One of the best experts on this subject based on the ideXlab platform.
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comparison between a chimeric lysin clyh and other enzymes for extracting dna to detect methicillin resistant staphylococcus aureus by quantitative pcr
World Journal of Microbiology & Biotechnology, 2016Co-Authors: Yuanyuan Hu, Hang Yang, Jian Wang, Yun Zhang, Junping YuAbstract:Extracting DNA from Staphylococcus aureus cells is important for detecting MRSA by PCR. However, S. aureus cells are known to be difficult to disrupt due to their compact cell walls. Here, we systematically studied the efficiency of a highly active lysin ClyH for extracting DNA of S. aureus in comparison with commonly used enzymes, such as lysostaphin and achromopeptidase (ACP), and its compatibility in quantitative PCR (qPCR) detection of MRSA. qPCR anaLysis of S. aureus specific gene femB showed that ClyH was much faster than lysostaphin, ACP and lysozyme for releasing DNA. Five minutes disruption with ClyH at room temperature was enough to release all the DNA from S. aureus. AnaLysis of the spiked nasal swabs by a dual qPCR assay of the β-lactam resistance mecA gene and the staphylococcal cassette chromosome (SCCmec)–open reading frame X (orfX) junction (SCCmec–orfX) after ClyH Lysis showed 100 % sensitivity and specificity to the commercial BD GeneOhm™ MRSA test with ACP Lysis, but the Lysis time was reduced from 20 min by ACP to 5 min by ClyH. Our research shows that ClyH could be a better option than the currently used enzymes for DNA extraction from S. aureus, which can provide simpler and faster PCR detection of MRSA.
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a chimeolysin with extended spectrum streptococcal host range found by an induced Lysis based rapid screening method
Scientific Reports, 2015Co-Authors: Hang Yang, Sara B Linden, Junping Yu, Jing Wang, Daniel C NelsonAbstract:The increasing emergence of multi-drug resistant streptococci poses a serious threat to public health worldwide. Bacteriophage lysins are promising alternatives to antibiotics; however, their narrow lytic spectrum restricted to closely related species is a central shortcoming to their translational development. Here, we describe an efficient method for rapid screening of engineered chimeric lysins and report a unique “chimeolysin”, ClyR, with robust activity and an extended-spectrum streptococcal host range against most streptococcal species, including S. pyogenes, S. agalactiae, S. dysgalactiae, S. equi, S. mutans, S. pneumoniae, S. suis and S. uberis, as well as representative enterococcal and staphylococcal species (including MRSA and VISA). ClyR is the first lysin that demonstrates activity against the dominant dental caries-causing pathogen as well as the first lysin that kills all four of the bovine mastitis-causing pathogens. This study demonstrates the success of the screening method resulting in a powerful lysin with potential for treating most streptococcal associated infections.
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study of the interactions between endolysin and bacterial peptidoglycan on s aureus by dynamic force spectroscopy
Nanoscale, 2015Co-Authors: Xuejie Zhang, Hang Yang, Junping Yu, Jinghe Yuan, Xiaohong FangAbstract:The cell wall binding domain (CBD) of bacteriophage lysins can recognize target bacteria with extraordinary specificity through binding to bacterial peptidoglycan, thus it is a promising new probe to identify the corresponding bacterial pathogen. In this work, we used atomic force microscopy (AFM) based single-molecule force spectroscopy to investigate the interaction between the CBD of lysin PlyV12 (PlyV12C) and pathogenic bacterium Staphylococcus aureus (S. aureus). The binding forces of PlyV12C with S. aureus have been measured, and the dissociation process of their binding complex has been characterized. Furthermore, we compared the interactions of PlyV12C–S. aureus and antibody–S. aureus. It is revealed that PlyV12C has a comparable affinity to bacterial peptidoglycans as that of the S. aureus antibody. The results provide new information on the binding properties of lysin CBD with bacterium, and the application of lysin CBD in bacterium detection.
Shigenobu Matsuzaki - One of the best experts on this subject based on the ideXlab platform.
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tail associated structural protein gp61 of staphylococcus aureus phage φmr11 has bifunctional lytic activity
Fems Microbiology Letters, 2008Co-Authors: Mohammad Rashel, Jumpei Uchiyama, Iyo Takemura, Hiroshi Hoshiba, Takako Ujihara, Hiroyoshi Takatsuji, Koichi Honke, Shigenobu MatsuzakiAbstract:A tailed bacteriophage, φMR11 (siphovirus), was selected as a candidate therapeutic phage against Staphylococcus aureus infections. Gene 61, one of the 67 ORFs identified, is located in the morphogenic module. The gene product (gp61) has lytic domains homologous to CHAP (corresponding to an amidase function) at its N-terminus and lysozyme subfamily 2 (LYZ2) at its C-terminus. Each domain of gp61 was purified as a recombinant protein. Both the amidase [amino acids (aa) 1–150] and the lysozyme (aa 401–624) domains but not the linker domain (aa 151–400) caused efficient Lysis of S. aureus. Immunoelectron microscopy localized gp61 to the tail tip of the φMR11 phage. These data strongly suggest that gp61 is a tail-associated lytic factor involved in local cell-wall degradation, allowing the subsequent injection of φMR11 DNA into the host cytoplasm. Staphylococcus aureus lysogenized with φMR11 was also lysed by both proteins. Staphylococcus aureus strains on which φMR11 phage can only produce spots but not plaques were also lysed by each protein, indicating that gp61 may be involved in ‘Lysis from without’. This is the first report of the presence of a tail-associated virion protein that acts as a lysin, in an S. aureus phage.
Desire Collen - One of the best experts on this subject based on the ideXlab platform.
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comparative fibrinolytic properties of staphylokinase and streptokinase in animal models of venous thrombosis
Thrombosis and Haemostasis, 1991Co-Authors: H. Roger Lijnen, J M Stassen, Kiyotaka Okada, Hideharu Fukao, Osamu Matsuo, I Vanlinthout, Desire CollenAbstract:: The thrombolytic and pharmacokinetic properties of staphylokinase were compared with those of streptokinase in hamsters with a pulmonary embolus produced from human plasma or from hamster plasma, and in rabbits with a jugular vein blood clot produced from rabbit blood. In both models, a continuous intravenous infusion of staphylokinase and streptokinase over 60 min in hamsters or over 4 h in rabbits, induced dose-dependent progressive clot Lysis in the absence of significant systemic activation of the fibrinolytic system. The results of thrombolytic potency (clot Lysis at 30 min after the end of the infusion, in percent, versus dose administered, in mg/kg) were fitted with an exponentially transformed sigmoidal function (formula: see text) and the maximal percent clot Lysis (c), the maximal rate of Lysis (z = 1/4 ac.eb) and the dose at which the maximal rate of Lysis is achieved (b) were determined. In hamsters with a pulmonary embolus produced from human plasma, streptokinase had a somewhat higher thrombolytic potency than staphylokinase, as revealed by a higher z value (2,100 +/- 1,100% Lysis per mg/kg streptokinase administered versus 1,100 +/- 330% Lysis per mg/kg for staphylokinase). In hamsters with a pulmonary embolus produced from hamster plasma, staphylokinase had a somewhat higher thrombolytic potency than streptokinase (z = 1,600 +/- 440 versus 1,200 +/- 370% Lysis per mg/kg). Staphylokinase had a higher thrombolytic potency than streptokinase in rabbits,as revealed by a higher z-value (950 +/- 350% Lysis per mg/kg staphylokinase administered versus 330 +/- 39% Lysis per mg/kg for streptokinase) and a lower b-value (0.035 +/- 0.010 mg/kg staphylokinase versus 0.091 +/- 0.008 mg/kg for streptokinase.(ABSTRACT TRUNCATED AT 250 WORDS)
David M Donovan - One of the best experts on this subject based on the ideXlab platform.
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Synergistic streptococcal phage λSA2 and B30 endolysins kill streptococci in cow milk and in a mouse model of mastitis
Applied Microbiology and Biotechnology, 2015Co-Authors: Mathias Schmelcher, Anne M. Powell, Mary J. Camp, Calvin S. Pohl, David M DonovanAbstract:Bovine mastitis results in billion dollar losses annually in the USA alone. Streptococci are among the most relevant causative agents of this disease. Conventional antibiotic therapy is often unsuccessful and contributes to development of antibiotic resistance. Bacteriophage endolysins represent a new class of antimicrobials against these bacteria. In this work, we characterized the endolysins (lysins) of the streptococcal phages λSA2 and B30 and evaluated their potential as anti-mastitis agents. When tested in vitro against live streptococci, both enzymes exhibited near-optimum lytic activities at ionic strengths, pH, and Ca^2+ concentrations consistent with cow milk. When tested in combination in a checkerboard assay, the lysins were found to exhibit strong synergy. The λSA2 lysin displayed high activity in milk against Streptococcus dysgalactiae (reduction of CFU/ml by 3.5 log units at 100 μg/ml), Streptococcus agalactiae (2 log), and Streptococcus uberis (4 log), whereas the B30 lysin was less effective. In a mouse model of bovine mastitis, both enzymes significantly reduced intramammary concentrations of all three streptococcal species (except for B30 vs. S. dysgalactiae ), and the effects on mammary gland wet weights and TNFα concentrations were consistent with these findings. Unexpectedly, the synergistic effect determined for the two enzymes in vitro was not observed in the mouse model. Overall, our results illustrate the potential of endolysins for treatment of Streptococcus -induced bovine mastitis.
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staphylococcus haemolyticus prophage φsh2 endolysin relies on cysteine histidine dependent amidohydrolases peptidases activity for Lysis from without
Journal of Biotechnology, 2012Co-Authors: Mathias Schmelcher, Nina Schischkova, Paul Kopylov, Sergey Pryamchuk, David M Donovan, N. Kiseleva, Olga Korobova, Igor AbaevAbstract:Staphylococcus aureus is an important pathogen, with methicillin-resistant (MRSA) and multi-drug resistant strains becoming increasingly prevalent in both human and veterinary clinics. S. aureus causing bovine mastitis yields high annual losses to the dairy industry. Conventional treatment of mastitis by broad range antibiotics is often not successful and may contribute to development of antibiotic resistance. Bacteriophage endolysins present a promising new source of antimicrobials. The endolysin of prophage ΦSH2 of Staphylococcus haemolyticus strain JCSC1435 (ΦSH2 lysin) is a peptidoglycan hydrolase consisting of two catalytic domains (CHAP and amidase) and an SH3b cell wall binding domain. In this work, we demonstrated its lytic activity against live staphylococcal cells and investigated the contribution of each functional module to bacterial Lysis by testing a series of deletion constructs in zymograms and turbidity reduction assays. The CHAP domain exhibited three-fold higher activity than the full length protein and optimum activity in physiological saline. This activity was further enhanced by the presence of bivalent calcium ions. The SH3b domain was shown to be required for full activity of the complete ΦSH2 lysin. The full length enzyme and the CHAP domain showed activity against multiple staphylococcal strains, including MRSA strains, mastitis isolates, and CoNS.
