(FAB01_091) Book reviews

Leon Battista Alberti, 'On the Art of Building in Ten Books' Translated by Joseph Rykwert, Neil Leach and Robert Tavemor L. A. Zhadova (ed.), 'Tatlin' (Budapest 1984). English translation Helen Ross, 'Just For Living, Aboriginal Perceptions of Housing in North West Australia' Tony Fry, 'Design History Australia: A Source Text in Methods and Resources' Phillip Cox and David Moore, 'The Australian Functional Tradition' Lenore Coltheart and Don Fraser (eds.), 'Lamdmarks in Public Works, Engineers and Their Works in New South Wales 1884-1914' Peter Bridges and Don MacDonald, 'James Barnet, Colonial Architect' Don Watson and Judith McKay, 'A Directory of Queensland Architects to 1940' Russell Walden, 'Voices of Silence: New Zealand's Chapel of Futuna' Jeremy Salmond, 'Old New Zealand Houses 1800-1940' Victoria Middleton, 'The Legend of Green Valley' Dyranda Prevost and Ann Rado, 'Living Places' Mark Jackson and Mark Stiles (directors), 'Universal Provider' Lars Lerup, 'Planned Assaults'

The spatial and temporal distribution of koala faecal pellets

Faecal pellets were collected under trees used by free-ranging koalas in south-western, central and southeastern Queensland to determine the spatial and temporal distribution of pellets with respect to the activity of koalas. Deposition of faecal pellets by koalas was analysed according to the time of day at which the tree was occupied. For free-ranging koalas, 47% of daily faecal pellet output was recovered using a collection mat of 8 x 8 m placed under a day-roost tree. The best predictor of pellet production was the presence of a koala in a tree between 1800 hours and midnight. For other periods, there was no relationship between period of tree occupancy and faecal pellet recovery. There was a significant relationship between the average length of tree occupancy and the time of day that a koala entered a tree.

The investigation of optimal bombardment parameters for transient and stable transgene expression in sorghum

This report outlines the development of optimized particle inflow gun (PIG) parameters for producing transgenic sorghum (Sorghum bicolor (L.) Moench). Both transient and stable expression were examined when determining these parameters. The uidA reporter gene (GUS) encoding beta -glucuronidase was used in transient experiments and the green fluorescent protein (GFP) used to monitor stable expression. Initially, optimization was conducted using leaf segments, as the generation of sorghum callus in sufficiently large quantities is time-consuming. Following leaf optimization, experiments were conducted using callus, identifying a high similarity between the two tissue types (r(s) = 0.83). High levels of GUS expression were observed in both leaf and callus material when most distant from the DNA expulsion point, and using a pressure greater than 1800 kPa. A higher level of expression was also observed when the aperture of the helium inlet valve was constricted. Using the optimized conditions (pressure of 2200 kPa, distance to target tissue of 15 cm from the expulsion point, and the aperture of the helium inlet valve at one full turn), three promoters (Ubiquitin, Actin1 and CaMV 35S) were evaluated over a 72-h period using GUS as the reporter gene. A significantly higher number of GUS foci were counted with the Ubiquitin construct over this period, compared to the Actin1 and CaMV 35S constructs. Stable callus sectors (on 2 mg l(-1) bialaphos) with GFP expression were visualized for as long as 6 wk post-bombardment. Using this optimized protocol, several plants were regenerated after having been bombarded with the pAHC20 construct (containing the bar gene), with molecular evidence confirming integration.

Maternal care and infant behaviour of the bridled nailtail wallaby (Onychogalea fraenata)

Bridled nailtail wallabies Onychogalea fraenata are endangered, medium-sized, nocturnal macropodids that persist at only one location in central Queensland, Australia. Characteristics of juvenile development, shelter use, anti-predator behaviour and maternal care were investigated in the wild using trapping, radio-tracking and spotlighting observations., Timing of developmental stages was identical to the pattern previously found in captivity, except for age at weaning which was much earlier in the wild. After young had left the pouch permanently at 17 weeks of age and weighing c. 800 g, they always spent the day concealed in dense cover, generally > 200 m from their mothers. Juveniles were also alone in > 50% of observations at night, and stayed closer to cover than did adult females. Young became independent of their mothers 7-8 weeks after permanent exit from the pouch and weighing c. 1800 g. Females with dependent juveniles changed their behaviour in ways likely to reduce predation on young. They reduced their home ranges, stayed closer to cover and became more wary than other females. Juveniles differed from adult females in their habitat use, anti-predator behaviour and shelter site preferences. Juveniles were more likely than adults to respond to threats by standing still or lying flat on the ground, whether or not they were in concealing cover. Juveniles used a wider range of smaller shelters than adults, and were less likely to use solid shelters such as hollow logs during the day. Because bridled nailtail wallabies have a 'hider' strategy of maternal care and the young rely on crypsis, successful breeding in the wild requires dense vegetation cover.

Multiple axon guidance cues establish the olfactory topographic map: how do these cues interact?

Each primary olfactory neuron stochastically expresses one of similar to1000 odorant receptors. The total population of these neurons therefore consists of similar to1,000 distinct subpopulations, each of which are mosaically dispersed throughout one of four semi-annular zones in the nasal cavity. The axons of these different subpopulations are initially intermingled within the olfactory nerve. However, upon reaching the olfactory bulb, they sort out and converge so that axons expressing the same odorant receptor typically target one or two glomeruli. The spatial location of each of these 1800 glomeruli are topographically-fixed in the olfactory bulb and are invariant from animal to animal. Thus, while odorant receptors are expressed mosaically by neurons throughout the olfactory neuroepithelium their axons sort out, converge and target the same glomerulus within the olfactory bulb. How is such precise and reproducible topographic targeting generated? While some of the mechanisms governing the growth cone guidance of olfactory sensory neurons are understood, the cues responsible for homing axons to their target site remain elusive.