The directional sensitivity of a bush cricket ear: a behavioural and neurophysiological study of Leptophyes punctatissima

ABSTRACT. The stereotyped response of the female Leptophyes punctatissima Bosc. to a representation of the male call has been taken as a behavioural measure to determine the directional sensitivity of monaurally deafened animals. By using the responses of an auditory interneuron (T-fibre), the directional sensitivity could also be measured neurophysiologically on the same preparation. Thus it was possible to compare directly both a behavioural and a neurophysiological polar directional plot for an individual. Both methods provided very similar results, showing an overall directionality of about 15 dB, with the maximum sensitivity of the ear occurring on the ipsilateral side.     

Microbial-assisted remediation of creosote- and pentachlorophenol-treated wood products

A recycling process designed to recover wood fiber from discarded utility poles and cross ties was tested. Laboratory and field studies were conducted using a combined physical, chemical and microbiological protocol designed for the removal of creosote and pentachlorophenol wood preservatives from wood fiber. Woodchips produced in an industrial type wood chipper were batch extracted in methanol. The extractions successfully removed more than 95% of eight major creosote compounds contained within the woodchips. An initial combined concentration of 29 262 ppm during the extraction phase was reduced to 95 ppm in the laboratory study and to 1364 ppm in the field study. Biopolishing with a microbial consortium containing adapted strains from the generaPseudomonas, Flavobacterium andAcinetobacter further reduced the preservative concentration to 8 ppm and 200 ppm, respectively, with anthracene being the most recalcitrant compound in both studies. Pentachlorophenol-treated wood with an initial concentration of 1190 ppm, when subjected to the recycling process, yielded end product wood containing less than 2 ppm of the preservative. The solvent/preservative mixture (miscella) produced during the extraction process yielded a pure methanol fraction and a still bottom mixture when subjected to flash distillation. Fractional (vacuum) distillation of the still bottom mixture produced methanol, creosote, pentachlorophenol, and coal tar fractions.     

Eastern Suburbs Banksia Scrub: Rescuing an endangered ecological community

On‐ground works prove an important mechanism for gaining knowledge about this near‐extinct ecological community, providing new insights into ways to manage and restore it.     

Expression of biotransformation genes in woodrat (Neotoma) herbivores on novel and ancestral diets: identification of candidate genes responsible for dietary shifts

The ability of herbivores to switch diets is thought to be governed by biotransformation enzymes. To identify potential biotransformation enzymes, we conducted a large-scale study on the expression of biotransformation enzymes in herbivorous woodrats ( Neotoma lepida ). We compared gene expression in a woodrat population from the Great Basin that feeds on the ancestral diet of juniper to one from the Mojave Desert that putatively switched from feeding on juniper to feeding on creosote. Juniper and creosote have notable differences in secondary chemistry, and thus, should require different biotransformation enzymes for detoxification. Individuals from each population were fed juniper and creosote diets separately. After the feeding trials, hepatic mRNA was extracted and hybridized to laboratory rat microarrays. Hybridization of woodrat samples to biotransformation probes on the array was 87%, resulting in a total of 224 biotransformation genes that met quality control standards. Overall, we found large differences in expression of biotransformation genes when woodrats were fed juniper vs. creosote. Mojave woodrats had greater expression of 10× as many biotransformation genes as did Great Basin woodrats on a creosote diet. We identified 24 candidate genes that may be critical in the biotransformation of creosote toxins. Superoxide dismutase, a free radical scavenger, was also expressed to a greater extent by the Mojave woodrats and may be important in controlling oxidative damage during biotransformation. The results are consistent with the hypothesis that biotransformation enzymes limit diet switching and that woodrats in the Mojave have evolved a unique strategy for the biotransformation of creosote toxins.