Prokaryotic expression and purification of soluble maize Ac transposase.

Transposons are mobile genetic elements that are found in all eukaryotic and prokaryotic species studied to date. The Maize Activator (Ac) transposase recognizes and excises Ac and Dissociation (Ds) elements and mediates insertion elsewhere in the genome. Insertions of Ds can cause disruption in gene sequences and hence are important functional genomics tool for tagging and cloning of unknown gene sequences. The involvement of Ac transposase (AcTPase) in Ds movement is well documented; however, protein structure and function of AcTPase is poorly understood. To express the maize AcTPase in E. coli, Ac cDNA was synthesized with an N-terminal 6xHis tag and cloned in pTrcAc expression vector. The expression cassette was induced in Rosetta2 (DE3) E. coli lines. End-point RT-PCR confirmed the integrity of AcTPase mRNA during cell culture. Autoinducing cultures grown at 37 °C produced prominent partial AcTPase products of ~40 kDa and ~70 kDa. Trypsin digestion and mass spectrometry analyses confirmed AcTPase in both the eluted peptides. When the cultures were grown at 22-25 °C for 24 h the expected ~90 kDa AcTPase soluble product was detected. The successful expression of full length AcTPase in soluble form allows further investigation of its structure and function.

Premature ejaculation: a clinical update.

Premature ejaculation (PE) is ejaculation occurring without control, on or shortly after vaginal penetration and before the subject wishes it, causing marked distress or interpersonal difficulties. PE is the most common male sexual complaint. Primary (lifelong) PE has a physiological basis. Therapy should involve the man and his partner. The primary aims of therapy are for the man to regain a sense of control over his ejaculation time and for him and his partner to feel satisfaction with sexual intercourse. The most effective therapies for primary PE are certain selective serotonin reuptake inhibitors, given on a daily basis or "on demand" before sexual activity. Topical anaesthetics have also been shown to be effective. The most common cause of secondary PE is declining erectile function. The approach to treating secondary PE is to treat the underlying condition.

Erectile dysfunction predicts generalised cardiovascular disease: evidence from a case-control study.

AIMS: To determine whether idiopathic erectile dysfunction, in the absence of overt cardiovascular disease or cardiovascular risk factors, is associated with vascular or autonomic dysfunction. METHODS: We studied 49 men with ED (without known cardiovascular risk factors or disease) and 50 age-matched controls, aged 40-70 years. Macrovascular endothelial function was examined by brachial artery ultrasonography and microvascular function by venous occlusion plethysmography. Blood pressure measurement and electrocardiography were performed lying and standing, and the 30:15 RR ratio calculated. RESULTS: Body mass index, testosterone, fasting lipids and glucose did not differ significantly between groups. Standing pulse pressure was higher (50+/-1mm Hg versus 43+/-2mm Hg, p<0.004) and 30:15 RR ratio lower (0.97+/-0.01 versus 1.01+/-0.01, p<0.02) in the ED group. Flow-mediated dilatation of the brachial artery was not significantly different between groups. Flow debt repayment during forearm reactive hyperaemia was lower in the ED group (7.2+/-0.7 ml versus 9.5+/-0.8 ml per 100ml, p<0.02) than in controls. CONCLUSIONS: Men with idiopathic ED have evidence of endothelial dysfunction in forearm resistance vessels, increased pulse pressure and impaired heart rate variability. This supports the concept that erectile dysfunction is a predictor of cardiovascular dysfunction and a precursor of clinical cardiovascular disease.