Martin G. Barker

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In three tropical rain forest light environments in Sabah, Malaysia, we compared photosynthesis in seedlings of ten climax tree species with putatively differing shade tolerances. The objectives of the study were (a) to characterise the range of photosynthetic responses in ten species of the Dipterocarpaceae and (b) to elucidate those photosynthetic(More)
Lianas, or woody climbing plants, are a major constituent of seasonally dry tropical forests, and are thought to impact negatively their host trees. In this study we evaluated whether liana presence was associated with reduced leaf water potentials and growth in adult Senna multijuga trees during the dry season in a lowland Bolivian forest. We used leaf(More)
Rodent studies have shown that furan is a hepatocarcinogen. Previous studies conducted with high doses showed tumors at nearly 100% incidence at all doses. In this paper, a ninety-day gavage experiment conducted with lower doses (0.0, 0.03, 0.12, 0.5, 2.0, and 8.0 mg/kg bw) to identify a no-observed adverse effect level for hepatotoxicity and to(More)
The toxicity of purified fumonisin B1 (FB1) administered ip was examined in male Sprague-Dawley rats. FB1 was injected at 7.5 or 10 mg/kg body weight/day for 4 consecutive days. This resulted in significant reductions in body weight, food consumption and faeces production. Polyuria without a compensatory increase in water consumption was observed in treated(More)
Fumonisins B1 and B2 (FB1 and FB2) are fungal secondary metabolites produced by members of the genus Fusarium. Although FB1 is usually detected in greater quantities, FB2 frequently co-occurs in contaminated feeds and foods and contributes to the total toxin load. In the present study, the comparative toxicity of FB1 and FB2 was examined in male(More)
Fumonisin B1 (FB1) is a fungal toxin produced by members of the genus Fusarium. Ingestion of FB1 causes species-specific neurotoxic, nephrotoxic, hepatotoxic and pulmonary effects. The clinical, haematological and pathological responses of adult male and female B6C3F1 mice to FB1 were assessed following 14 daily gavage doses ranging from 1 to 75 mg FB1/kg(More)
Toxaphene, which was added to glycerol/corn oil, was administered at a level of 1 mg/kg body weight/day in gelatin capsules to four healthy young adult cynomolgus (Macaca fascicularis) monkeys for 52 weeks. Four control monkeys ingested capsules containing only glycerol/corn oil. Each group had two males and two females. On a daily basis, each monkey's feed(More)
Conducting research in forest canopies is accompanied by both opportunities and difficulties. Opportunities occur because the canopy is important in overall forest structure and function, for example in containing a high proportion of species richness, being the site of forest-atmosphere fluxes, and in strongly influencing understory microclimate. However,(More)
Male rats were gavaged with fumonisin B1 (FB1) once daily for 11 consecutive days at doses of 0, 1, 5, 15, 35, and 75 mg FB1/kg body weight. Urine osmolality (at 5-75 mg FB1/kg) and organic ion transport in kidney slices (at 5-75 mg FB1/kg) were reduced. Urinary excretion of protein (at 15-75 mg FB1/kg) and of the enzymes LDH (at 5-75 mg FB1/kg), NAG (at(More)