Using ontologies to describe mouse phenotypes

The mouse is an important model of human genetic disease. Describing phenotypes of mutant mice in a standard, structured manner that will facilitate data mining is a major challenge for bioinformatics. Here we describe a novel, compositional approach to this problem which combines core ontologies from a variety of sources. This produces a framework with greater flexibility, power and economy than previous approaches. We discuss some of the issues this approach raises.     

Metabolic fate of 3,4-dichloropropionanilide in plants: the metabolism of the propionic Acid moiety

3,4-Dichloropropionanilide-¹⁴C (propanil) labeled in either the C-1 or C-3 carbon atoms of the propionic acid moiety was applied to the roots of pea (Pisum sativum L.) and rice (Oryza sativa L.) plants in nutrient solution (0.1 mm-0.28 mm). Radioactivity was detected throughout the treated plants, but the greatest labeling was found in the roots. None of the products that contained aniline were radioactive, suggesting that the plants split the propionic acid moiety from propanil. The fate of the propionate moiety of propanil was determined by recovery of ¹⁴CO₂ from plants exposed to propanil-¹⁴C. The time-course of the ¹⁴CO₂ production demonstrated that the intact propionic acid was cleaved from the propanil and subsequently catabolized by the β-oxidation catabolic sequence. The appearance of radioactivity in the shoots was attributed to the incorporation of products of propionate metabolism. Both the susceptible pea plants and the tolerant rice plants converted a high percentage of the administered propanil-¹⁴C to ¹⁴CO₂.     

Regeneration of fertile Arachis paraguariensis plants from callus and suspension cultures

Highly morphogenic callus cultures were isolated from stamens of a wild peanut species, Arachis paraguariensis. These cultures were initiated on modified N6 medium containing 0.2 mg1l^-1 4amino-3,5,6-trichloro-picolinic acid (picloram) and 0.5 mg l^-1 6-benzylaminopurine (BAP) and were maintained on modified N6 medium with 0.008 mg l^-1 picloram and 0.25 mg l^-1 BAP. Buds formed on the calli growing on the maintenance medium developed into shoots when they were transferred to a MS salts based medium with no hormones. The cultures could also be maintained as a suspension culture in N6 liquid medium. When cell clumps larger tham 840 m were collected from the suspension culture and transferred to MS medium without hormones, they formed shoots in liquid culture. Root formation rarely occurred in agar or liquid cultures. Therefore, grafting to stems of rooted seedlings was used to obtain plants from regenerated shoots. Eight out of 50 field grown plants produced viable seed.     

Olfactory sensitivity in tsetse flies: a daily rhythm

The diurnal tsetse Glossina morsitans morsitans bites especially in early morning and late afternoon; around midday feeding is at a low. In laboratory apparatus that measures the amount of locomotion under constant conditions over the photophase, the flies display a similar patterning of activity levels. The profile of daily rhythms for G. morsitans reported in the literature includes a number of motor and sensory motor systems that fluctuate cophasically. Lacking is a study on the patterning of the senses' response levels. In this paper we present the first instance of a daily modulation in the sense of smell. We stimulated the antennae with concentration series of host-derived odours and measured the spiking rate of cells at different times during the photophase. The concentration-response curves suggest that the sensitivity of antennal olfactory cells flows in parallel with the other daily rhythms. This was also reflected in electroantennograms (EAGs). The electroantennography was extended to G. fuscipes fuscipes, whose level of spontaneous locomotor activity--instead of following a U- shaped pattern--rises gradually over the photophase. Again, the EAGs appeared to parallel the species' locomotor activity. What we believe happens is that the organism tones down the sensitivity of its odour receptors during periods of anticipated inactivity for reasons of economy.