The isopentenyl isoflavone luteone as a pre-infectional antifungal agent in the genus Lupinus

The prenylated isoflavone luteone has been isolated from healthy leaves of Lupinus albus and 11 other lupin species. Evidence is presented that this compound occurs as a leaf surface constituent. In vitro tests indicate that luteone and a second unidentified isoflavone frorn L. albus possess antifungal activity sufficient to support their proposed role as pre-infectional resistance factors. No evidence was obtained to suggest that phytoalexins were produced by the fungus-infected leaves of L. albus.     

An isoflavan phytoalexin from leaves of Glycyrrhiza glabra

An isoflavonoid phytoalexin isolated from the leaves of Glycyrrhiza glabra has been characterised as 7,2′-dihydroxy-3′,4′-dimethoxyisoflavan     

Suppression of Meloidogyne chitwoodi with Sudangrass Cultivars as Green Manure

Meloidogyne chitwoodi race 1 reproduced on Piper sudangrass (Sorghum bicolor (L.) Moench), 332 (sudangrass hybrid), and P855F and P877F (sorghum-sudangrass hybrids), but failed to reproduce efficiently on Trudan 8, Trudex 9 (sudangrass hybrids), and Sordan 79, SS-222, and Bravo II (sorghum-sudangrass hybrids). Meloidogyne chitwoodi race 2 behaved similarly and reproduced more efficiently on Piper, P855F, and P877F than on Trudan 8, Trudex 9, or Sordan 79. The mean reproductive factor for M. chitwoodi races on the poorer hosts ranged from <0.1 to 0.9 under greenhouse and field conditions. Meloidogyne hapla failed to reproduce on any of the cultivars tested. In the laboratory, leaves of each cultivar chopped and incorporated as green manure reduced the M. chitwoodi population in infested soil more than unamended or wheat green manure treatments. Trudan 8, although limited to the zone of incorporation, protected this zone from colonization of upward migrating second stage juveniles (J2) for up to 6 weeks. Leaves of Trudan 8 but not roots were effective against M. chitwoodi, and J2 appeared to be more sensitive than egg masses. Trudan 8 and Sordan 79 as green manure reduced M. chitwoodi in bucket microplots under field conditions.     

Microbial colonization of an in vitro model of a tissue engineered human skin equivalent – a novel approach

This was a preliminary investigation to define the conditions of colonization of a human skin equivalent (SE) model with cutaneous microorganisms. SEs of 24 mm diameter were constructed with a dermal matrix of fibrin containing fibroblasts and a stratified epidermis. Microbial colonization of the SEs was carried out in a dry environment, comparable to ' in vivo ' skin, using a blotting technique to remove inoculation fluid. The microbial communities were sampled by scrub washing and viable cells enumerated on selective growth medium. Staphylococcus epidermidis , Propionibacterium acnes and Malassezia furfur (human skin commensals) and Staphylococcus aureus (transient pathogen) were colonized at inoculum densities of 10²–10⁶ CFU SE⁻¹ on the surface of replicate SEs. Growth of all species was supported for upto 72–120 h, with recovery densities of between 10⁴–10⁹ CFU SE⁻¹. A novel, real-time growth monitoring method was also developed, using S. aureus containing a lux cassette. Light output increased from 20 to 95 h, and colonization increased from 10² to 10⁸ CFU SE⁻¹, as confirmed by conventional recovery. Thus, the SE model has potential to investigate interactions between resident and transient microbial communities with themselves and their habitat, and for testing treatments to control pathogen colonization of human skin.