Biomedical subjects

J Jaynes

Publications and source records attributed to J Jaynes.

12 recordsLinked to original sources

PubMed1999

In vitro activities of designed antimicrobial peptides against multidrug-resistant cystic fibrosis pathogens.

The emergence of multidrug-resistant pathogens renders antibiotics ineffective in the treatment of lung infections in patients with cystic fibrosis (CF). Designed antimicrobial peptides (DAPs) are laboratory-synthesized peptide antibiotics that demonstrate a wide spectrum of antibacterial activity. Optimal conditions for susceptibility testing of these peptides have not yet been established. Medium composition is clearly a major factor influencing the results and reproducibilities of susceptibility tests. Using time-kill assays, we tested the effects of different media and buffers on the bactericidal activities of the peptides D2A21 and D4E1 on Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853. Each peptide at 1 and 5 microM was incubated with bacteria in the different media and buffers. Both peptides were most active in Tris-HCl buffer against S. aureus and P. aeruginosa. Among the more complex media tested, modified RPMI medium was the medium in which the peptides demonstrated the highest activity, while it supported the growth of the bacteria. The broth microdilution technique was used to test the activities of D2A21 and D4E1 in modified RPMI medium against multidrug-resistant pathogens from patients with CF. The MICs of DAPs for methicillin-resistant S. aureus ranged from 0.25 to 4 microg/ml, those for multidrug-resistant P. aeruginosa ranged from 0.125 to 4 microg/ml, those for Stenotrophomonas maltophilia ranged from 0.5 to 32 microg/ml, and those for Burkholderia cepacia ranged from 32 to >/=64 microg/ml. When the activity of peptide D2A21 was compared with that of the tracheal antimicrobial peptide (TAP), D2A21 had greater potency than TAP against P. aeruginosa. In addition, no difference in the MICs of D2A21 was seen when it was tested in nutrient broth supplemented with NaCl at different concentrations. Thus, DAPs are a class of salt-insensitive antibiotics potentially useful in the treatment of CF patients harboring multidrug-resistant P. aeruginosa.

Amino Acid Sequence↗

PubMed1997

An amphipathic alpha-helical synthetic peptide analogue of melittin inhibits herpes simplex virus-1 (HSV-1)-induced cell fusion and virus spread.

The effects of hecate, a 23-amino acid synthetic peptide analogue of melittin, on HSV-1-induced cell fusion and virus multiplication was investigated. Hecate completely inhibited cell fusion induced by HSV-1 syncytial (syn) mutants HSV-1 HFEM (tsB5) and HSV-1 mp (MP) at a concentration of 5.0 microM. Metabolic labeling experiments indicated that hecate did not adversely affect cellular growth and protein synthesis. The synthesis of virus-specified glycoproteins B, C, D, and H was reduced in the presence of hecate; however, the transport of these glycoproteins to the surface of infected cells was not affected. Production of infectious virions for wild-type and syn mutants tsB5 and MP was reduced in the presence of hecate. The effect of hecate on virus titer was dependent on the multiplicity of infection. Virus titers were reduced 2-28-fold at an M.O.I. of 0.1, 3-6-fold at an M.O.I. of 0.5, and 0-2.5-fold at an M.O.I. of 2.5. Direct treatment of semipurified virions with hecate reduced titers by approximately 4-fold for KOS, 2-fold for tsB5, and over 30-fold for MP.

Amino Acid Sequence↗

PubMed1996

The use of synthetic Cecropin (D5C) in disinfecting contact lens solutions.

PURPOSE: Microbial keratitis caused by Pseudomonas aeruginosa is the most common contact lens associated corneal infection. Cecropins are microbicidal peptides isolated from the hemolymph of the Cecropia moth. Previous in vitro studies have demonstrated their efficacy against a broad spectrum of ocular pathogens. This study was designed: a) to evaluate the antimicrobial potency of three different contact lens solutions (Renu, Complete, and Opti-Free) against P. aeruginosa, and b) to evaluate the activity of the same contact lens solutions in combination with a synthetic cecropin analog, D5C, against the challenge organism in the presence of a soft contact lens. METHODS: A virulent strain of P.aeruginosa isolated from a case of ulcerative keratitis was used in the study. Three different concentrations of bacteria (10(3), 10(5) and 10(7) CFU/mL) were inoculated into the contact lens solutions and into buffered saline, which was employed as a control. The samples were incubated at 27 degrees C, and at time 0, 30, and 90 minutes, 24, 48, and 72 hours, and aliquots of the test solutions were plated and subcultured on nutrient agar. After 24 hours of incubation at 37 degrees C, colonies observed on the nutrient agar plates were counted. To study the antimicrobial efficacy of D5C (100 micrograms/mL), we used the identical test series and assay, adding a soft contact lens to the solutions and a larger inoculum of bacteria (10(9) CFU/mL). RESULTS: After 72 hours, all of the contact lens solutions tested sterilized 10(3) CFU/mL of P. aeruginosa. At 10(7) CFU/mL, they yielded greater than 2 logs of killing of the bacteria, but the solutions were not sterilized. The addition of D5C (100 micrograms/mL) to the contact lens solutions yielded greater than 3 logs of killing with a larger inoculum of bacteria in the presence of the soft contact lens. CONCLUSION: The contact lens solutions tested were effective against P. aeruginosa at 27 degrees C for up to 72 hours with an inoculum of 10(3) CFU/mL. The addition of D5C augmented their antimicrobial activity in the presence of the contact lens.

Colony-Forming Units Assay↗

PubMed1995

Shiva-1: in vitro and in vivo tests of the effects of a novel, synthetic, lytic peptide on ocular cells.

An investigation was undertaken to determine the toxicity of an intravitreal injection of a novel peptide drug, Shiva-1, in rabbits. The drug, a synthetic peptide modeled after lytic peptides secreted by certain insects, has antiproliferative and antibacterial properties. Initial in vitro experiments showed that the drug, at a concentration of 100 microM, was toxic to both Y-79 retinoblastoma cells and human retinal pigment epithelial cells. A wide range of doses (6-1200 micrograms) was injected into the rabbit vitreous in an attempt to determine the maximum tolerated dose. Retinal toxicity was evaluated clinically, by electroretinography, and by light microscopy. Some localized toxicity was evident at 200 micrograms; all doses of 240 micrograms and above were toxic. While the drug appears to exhibit a narrow range between effective and toxic doses, the results suggest that this and other peptides of similar design merit further investigation for the treatment of proliferative and infectious diseases of the eye.

Animals↗

PubMed1994

In vitro antimicrobial activity of Shiva-11 against ocular pathogens.

Cecropins are antimicrobial peptides (30-35 amino acids) isolated from the hemolymph of the cecropia moth. Previous studies have demonstrated their antimicrobial efficacy against a variety of pathogens, including both gram-positive and -negative bacteria, fungi, protozoa, and enveloped viruses. To assess their therapeutic potential against ocular pathogens, we analyzed the in vitro antimicrobial activity of a synthetic cecropin analog, Shiva-11, against virulent microbial strains (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans). Bacterial isolates were obtained from human cases of severe ulcerative keratitis. Shiva-11 was tested at varying concentrations in bacterial suspensions containing 1-2 x 10(6) CFU/ml at 37 degrees C. Samples were plated on nutrient agar and colonies counted after 24-48 h of incubation. Shiva-11 yielded > 3 log killing of all isolates after 60 min of exposure to this compound. The results of this study indicate that Shiva-11 possesses broad-spectrum in vitro antimicrobial activity against human clinical ocular pathogens.

Animals↗

PubMed1974