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891.
Kevin H. Mayo Judith Haseman Elena Ilyina Beulah Gray 《Biochimica et Biophysica Acta (BBA)/General Subjects》1998,1425(1):81-92
Novel peptide 33mers have been designed by incorporating β-conformation stabilizing residues from the β-sheet domains of α-chemokines and functionally important residues from the β-sheet domain of human neutrophil bactericidal protein (B/PI). B/PI is known for its ability to kill bacteria and to neutralize the action of bacterial endotoxin (lipopolysaccharide, LPS) which can induce septic shock leading to eventual death. Here, the goal was to make short linear peptides which demonstrate good β-sheet folding and maintain bioactivity as in native B/PI. A library of 24 peptide 33mers (βpep-1 to βpep-24) were synthesized with various amino acid substitutions. CD and NMR data acquired in aqueous solution indicate that βpep peptides form β-sheet structure to varying degrees and self-associate as dimers and tetramers like the α-chemokines. Bactericidal activity toward Gram-negative Pseudomonas aeruginosa was tested, and βpep-19 was found to be only about 5-fold less potent (62% kill at 1.2×10?7 M) than native B/PI (80% kill at 2.9×10?8 M). At LPS neutralization, βpep-2 and -23 were found to be most active (66–78% effective at 1.2×10?6 M), being only about 50–100-fold less active than B/PI (50% at 1.5×10?8 M). In terms of structure–activity relations, β-sheet structural stability correlates with the capacity to neutralize LPS, but not with bactericidal activity. Although a net positive charge is necessary for activity, it is not sufficient for optimal activity. Hydrophobic residues tend to influence activities indirectly by affecting structural stability. Furthermore, results show that sequentially and spatially related residues from the β-sheet domain of native B/PI can be designed into short linear peptides which show good β-sheet folding and retain much of the native activity. This research contributes to the development of solutions to the problem of multiple drug-resistant, opportunistic microorganisms like P. aeruginosa and of agents effective at neutralizing bacterial endotoxin. 相似文献
892.
A plasmid known to be associated with mupirocin resistance of Staphylococcus aureus has been isolated and a restriction enzyme map constructed. An EcoRI fragment of 4.05 kb from this plasmid has been cloned into an Escherichia coli-Staphylococcus aureus shuttle vector and shown to carry the gene for resistance to mupirocin. The DNA sequence of a small section of the gene has been determined and the derived amino acid sequence compared with a data bank. The amino acid sequence is identical for eight amino acids with the sequence of isoleucyl tRNA synthetase of E. coli. This finding adds to the evidence that mupirocin resistance is the result of a modified isoleucyl tRNA synthetase. 相似文献
893.
Satoshi Imai Takuya Ooki Naoko Murata-Kamiya Daisuke Komura Kamrunnesa Tahmina Weida Wu Atsushi Takahashi-Kanemitsu Christopher Takaya Knight Akiko Kunita Nobumi Suzuki Adriana A. Del Valle Mayo Tsuboi Masahiro Hata Yoku Hayakawa Naomi Ohnishi Koji Ueda Masashi Fukayama Tetsuo Ushiku Masanori Hatakeyama 《Cell host & microbe》2021,29(6):941-958.e10
894.
In vitro adherence of the nosocomial pathogensPseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, andCandida albicans to select radiopaque silicone compounds was lower than that observed for the base silicone (p<0.03). Except forE. coli ATCC 11775 andCandida albicans, all microorganisms showed significantly lower adherence to a silicone compound impregnated with tantalum in comparison with a silicone compound impregnated with barium sulfate (p<0.05). Surface hydrophobicity of the silicone compounds did not show a direct correlation with the concentration of radiopacity additives or with degree of bacterial adherence. Scatchard analyses of data indicated that the number of adherence sites forP. aeruginosa on the base silicone, BaSO4-silicone, and Ta-silicone were 9.2×106 per mm2, 6.1×106 per mm2, and 3.7×106 per mm2 respectively. As determined by the Langmuir adsorption isotherm, the dissociation constants for adheredP. aeruginosa to the base silicone, BaSO4-silicone, and Ta-silicone were 2.50×103 mm4, 1.45×103 mm4, and 6.27×103 mm4 respectively.Pseudomonas aeruginosa demonstrated first order kinetics of adherence to the silicone compounds with a half saturation time of 4.15 h for the base silicone, 1.06 h for the BaSO4-silicone, and 2.14 h for the Ta-silicone. The use of Ta-silicone stents may delay the development of ascending urinary tract infections. 相似文献