Transcriptional activation of the Agrobacterium tumefaciens vir regulon is regulated by phenolics such as acetosyringone (AS), certain monosaccharides, and acidic conditions produced by wounded plant cells.

Both cyclo-oxygenase enzymes are expressed in normal human upper respiratory epithelium and are not upregulated in chronic sinusitis nor in nasal polyposis, possibly suggesting that Cox products do not have an important role as mediators of the chronic upper airway inflammation.

Although the basic elements of the two-component system required for phenol-mediated induction of virulence gene expression are encoded on the Ti plasmid, they are dependent on the chromosomal background for even the very first stage of signal perception. This discovery suggests a curious evolutionary history, and also provides functional insight into the mechanisms of two-component signal detection and transmission in general.

Acute infective inflammation of the epiglottis and supraglottic tissues in the adult is an uncommon but life-threatening condition. 1•4 The incidence of adult cases may even be on the increase. 5 However, epiglottitis in association with infection of a pre-existing epiglottic cyst is unusual. CASE REPORT In January 1988 a 62-year-old man presented with several hours history of sore throat, dysphagia and pyrexia. A cyst on the left side of his epiglottis had previously been noted in May 1985 during the course of an anaesthetic laryngoscopy. The epiglottic cyst had been asymptomatic and had required no treatment at that time. On admission to hospital his axillary temperature was 37.5°C. There was a cellulitis of the skin overlying the anterior aspect of his neck and sternum. The patient had a muffled voice and was unable to swallow his saliva. However, he had no stridor in the sitting position at rest and had no palpable lymph nodes. Humidified oxygen therapy was administered to the patient in the sitting position. Throat swabs, blood cultures, a full blood count and a lateral soft tissue X-ray of neck were obtained. The lateral X-ray of neck demonstrated the extended cervical spine typical of upper airways obstruction, widening of the prevertebral soft tissue •F.F.A.R.C.S .. Senior Registrar in Anaesthesia.