Tolypocladium cylindrosporum (Deuteromycotina:Moniliales), a fungal pathogen of the mosquito Aedes australis

A laboratory fermenter was used to produce up to 12 l of infective Tolypocladium cylindrosporum blastoconidia in Sabouraud dextrose broth. Two media derived from coconuts were also demonstrated as suitable alternative systems for the production of viable blastoconidia. T. cylindrosporum conidia when dried at 37 degrees C and stored at 4 degrees C retained their viability for 10 months, but, when stored at 25 degrees C, the conidia lost viability after 2 months and blastoconidia did not survive the drying process. Distilled water suspensions were a simple, economic technique for the long-term storage of spores at both 4 and 25 degrees C. The adsorption of conidia onto silica gel crystals was a very suitable technique for the storage of stock culture material at 4 degrees C. The virulence, production and storage capabilities of both spore types were examined.     

Gel-phase synthesis of a 43-mer peptide from the CD 4-binding domain of human immunodeficiency virus envelope glycoprotein on butanediol dimethacrylate cross-linked polystyrene support

A high yielding gel-phase synthesis of a 43-residue sequencecorresponding to 381-423 CD 4-binding domain of humanimmunodeficiency virus envelope glycoprotein (HIV-gp) in completehomogeneity and quantity on a newly developed butanedioldimethacrylate cross-linked polystyrene support (PS-BDODMA) isdescribed. The synthesis, cleavage and purification of the 43-residue peptide as well as other corresponding shorter sequences, HIV-gp (416-423), HIV-gp (404-423) and HIV-gp (389-423) proceededin great efficiency on the highly solvating chloromethylatedPS-BDODMA support. These four peptides were isolated in sufficientquantity and their homogeneity and identity were established byamino acid analysis, characteristic HPLC patterns and MALDI TOFmass spectrometry. This stepwise gel-phase synthesis illustratesthe application of the new resin which can be easily prepared byradical aqueous suspension copolymerisation of styrene andbutanediol dimethacrylate followed by chloromethylation.     

Nonlinear variation in clinging performance with surface roughness in geckos

Understanding the challenges faced by organisms moving within their environment is essential to comprehending the evolution of locomotor morphology and habitat use. Geckos have developed adhesive toe pads that enable exploitation of a wide range of microhabitats. These toe pads, and their adhesive mechanisms, have typically been studied using a range of artificial substrates, usually significantly smoother than those available in nature. Although these studies have been fundamental in understanding the mechanisms of attachment in geckos, it is unclear whether gecko attachment simply gradually declines with increased roughness as some researchers have suggested, or whether the interaction between the gekkotan adhesive system and surface roughness produces nonlinear relationships. To understand ecological challenges faced in their natural habitats, it is essential to use test surfaces that are more like surfaces used by geckos in nature. We tested gecko shear force (i.e., frictional force) generation as a measure of clinging performance on three artificial substrates. We selected substrates that exhibit microtopographies with peak‐to‐valley heights similar to those of substrates used in nature, to investigate performance on a range of smooth surfaces (glass), and fine‐grained (fine sandpaper) to rough (coarse sandpaper). We found that shear force did not decline monotonically with roughness, but varied nonlinearly among substrates. Clinging performance was greater on glass and coarse sandpaper than on fine sandpaper, and clinging performance was not significantly different between glass and coarse sandpaper. Our results demonstrate that performance on different substrates varies, probably depending on the underlying mechanisms of the adhesive apparatus in geckos.     

Work of adhesion of respiratory tract mucus.

A method was devised to measure the work of adhesion (WA) to a substrate of mucus, a viscoelastic gel, from the measured contact angle of glycerol on a mucus substrate and the known physical properties of a Teflon surface. Fifteen sputum samples from cystic fibrosis (CF) patients were compared with 25 mucus samples from canine tracheal pouches (CP), studied in the hydrated and partially dehydrated states. Apparent viscosity (eta A) and recoverable shear strain (SR) were measured by fluxgate magnetometry, and water content was inferred from vapor pressure osmometry. Na+, K+, and Ca2+ concentrations were measured with specific ion electrodes and Cl- with a chloridimeter. The Cl- concentration of the CP mucus was inversely proportional to its osmolality, and the Cl- concentration of the CP mucus was 102.5 +/- 1.6 meq/l compared with 55.6 +/- 2.5 meq/l for CF sputum. When CP mucus osmolality was increased from 316.0 +/- 5.5 to 430.0 +/- 7.5 mosmol/kg, WA increased from 25.1 +/- 1.8 to 31.1 +/- 1.2 ergs/cm2 and eta A increased from 391 +/- 55 to 622 +/- 121 P, respectively. CF sputum WA was 30.2 +/- 0.6 ergs/cm2, eta A was 1,110 +/- 316 P, and osmolality was 466.0 +/- 14.0 mosmol/kg. The increased WA and eta A of mucus in CF patients may thus be dependent on the hydration of mucus, which is related to the documented Cl- transport defect.     

Polymorphisms involving the transmembrane domains of human TAP2

Correspondence to: S. Pillai.     

Performance and survival of different races of Puccinia graminis f.sp. tritici on detached leaves of wheat

The detached leaf culture of Puccinia graminis f.sp. tritici was tested with eight races and two biotypes of the pathogen. The inherent characteristics of the races were similar to those in intact plants. Continuous maintenance of races in pure culture on detached leaves showed the usefulness of the technique for multiplication of inoculum as well as for maintenance of races in other basic studies.