Calcineurin, synaptic plasticity, and memory.
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Animals↗
Biomedical subjects
D Winder
Publications and source records attributed to D Winder.
Tethered flight activity of Nephotettix virescens (Hemiptera: cicadellidae) in the Philippines.
The flight potential of Nephotettix virescens (Distant), the most important vector of rice tungro virus disease, was assessed using tethered flight techniques. Most individuals tested were not willing to fly in response to stimulation, or flew for very short times. A small proportion of leafhoppers flew for long periods and one female flew for almost 7 h, indicating the potential for long distance dispersal of insects and inoculum. Few individuals flew before four days of age and thereafter flight profiles were similar for insects aged between four and 12 days. Mature females were more flight willing when kept as adults in mixed groups with males than when caged separately. There was no consistent effect on flight performance when insects were reared on rice varieties with different levels of leafhopper resistance. The flight activity of N. virescens was greater when leafhoppers were reared on mature, compared with young, rice plants. Leafhoppers reared through one generation on tungro-diseased rice plants were less willing to fly than individuals maintained on healthy plants of the same age and variety, whereas those tested after a 24-h access period to tungro-diseased plants were more flight-willing. The results are discussed in relation to the spread of tungro and to management interventions for the control of the disease.
Age Factors↗
Needle injection catheter delivery of the gene for an antibacterial agent inhibits neointimal formation.
Percutaneous transluminal coronary angioplasty is a routinely used non-surgical revascularization technique for patients with coronary artery disease. Up to 30% of patients undergoing coronary angioplasty develop a renarrowing of treated vessels, called restenosis. Smooth muscle cell proliferation is thought to be an important factor in restenosis; this leads to neointima formation and arterial lumen narrowing. Neointima may be reduced by the transfer of genes encoding proteins with antiproliferative effects. Cecropins are antimicrobial peptides with antiproliferative properties in mammalian cells. Cecropin A is one member of this family of peptides. In this article, a plasmid carrying the gene for the immature form, pre-pro-cecropin A, complexed with liposomes was locally delivered to perivascular tissue in a porcine arterial injury model using a needle injection catheter. Retention of the plasmid in the treated arteries was demonstrated at both 8 and 21 days following application. Transferred plasmid DNA was not detected in any other tissues analyzed. Pre-pro-cecropin A-specific transcripts could also be found in treated arteries. Balloon-injured vessels demonstrated significantly reduced neointima at 21 days in vessels treated with the pre-pro-cecropin A gene compared with neointimal area in those given a control gene (P < 0.05). The needle injection catheter appears to be useful for local intravascular gene delivery. In vivo gene transfer of cecropins may be of therapeutic relevance in restenosis prevention by limiting cell proliferation.
Angioplasty, Balloon, Coronary↗
Expression of antimicrobial peptides has an antitumour effect in human cells.
The antimicrobial peptides cecropin and melittin are known to exhibit antitumour activity in tumour derived cell lines. To achieve a similar effect in vivo these peptides would have to be given repeatedly to maintain therapeutic levels, which may be pharmacologically unfavourable. The expression of the genes encoding such antimicrobial peptides in the desired cell type may circumvent these problems. Expression constructs carrying cecropin or melittin have been introduced into a human bladder carcinoma derived cell line and the resultant cell clones analysed for tumorigenicity in nude mice. Expression of cecropin resulted in either a complete loss of tumorigenicity in some clones or reduced tumorigenicity, as measured by latency of tumour formation. These results suggest that vector mediated delivery of this gene to tumour cells may prove useful for cancer gene therapy.
Animals↗
Antimicrobial peptides melittin and cecropin inhibit replication of human immunodeficiency virus 1 by suppressing viral gene expression.
Antimicrobial peptides are effectors of innate immunity, providing their hosts with rapid non-specific defence against parasitic invaders. In this report, the effects are assessed of two well-characterized antimicrobial amphipathic peptides (melittin and cecropin) on human immunodeficiency virus 1 (HIV-1) replication and gene expression in acutely infected cells at subtoxic concentrations. Production of infectious, cell-free virus was inhibited in a dose-dependent manner, with ID50 values in the range 0.9-1.5 microM for melittin and 2-3 microM for cecropin. Analysis of the effect of melittin on cell-associated virus production revealed decreased levels of Gag antigen and HIV-1 mRNAs. Transient transfection assays with HIV long terminal repeat (LTR)-driven reporter gene plasmids indicated that melittin has a direct suppressive effect on activity of the HIV LTR. HIV LTR activity was also reduced in human cells stably transfected with retroviral expression plasmids for the melittin or cecropin gene. It is concluded that antimicrobial peptides such as melittin and cecropin are capable of inhibiting cell-associated production of HIV-1 by suppressing HIV-1 gene expression.
Anti-Infective Agents↗