Phosphate Compounds in Vertebrate Red Blood Cells

This review brings together and discusses the significance ofexisting information about water-soluble (small molecule) organicphosphate constituents of red blood cells in different vertebratespecies, with emphasis on 2,3 diphosphoglycerate (DPG), inositolpentaphosphate (IP₅) ATP and guanosine triphosphate (GTP), compoundswhich may play an important role in respiratory physiology bymodifying the affinity of hemoglobin for oxygen. Results onthe distribution and concentration of these compounds in redcells of vertebrate animals can be summarized as follows 1)DPG High in mammals (except cats and ruminants) Absent in crocodilianssquamata and fishes. High briefly in the bird embryo absentin adult. High briefly in turtle embryo low in juvenile lowto absent in adult 2 IP₅. High in birds. Absent in mammals,crocodilians squamata and fishes (with the exception of Arapaimagigas). Low in turtles 3 ATP Intermediate in mammals. High inbirds and turtles. Very high in squamata Intermediate to veryhigh in fishes. Low in crocodilians 4) GTP Very low in mammalsbirds, reptiles and amphibians (except for small pool in Ranatadpole). Low to very high in fishes.     

Taste receptor activity and feeding behaviour reveal mechanisms of white spruce natural resistance to Eastern spruce budworm Choristoneura fumiferana

The pattern of feeding of Eastern spruce budworm Choristoneura fumiferana (Clem.) (Lepidoptera, Tortricidae) is compared on foliage from white spruce Picea glauca (Moench) Voss. (Pinaceae) trees previously determined to be susceptible and resistant to defoliation by budworm. No differences are observed in electrophysiological responses from taste sensilla to aqueous extracts of the two foliage types, nor is there a preference for either extract type in a choice test. Acetone extracts from the two foliage types are both preferred to a control sucrose solution, although neither elicits a preference relative to the other. These results suggest that there is no difference in phagostimulatory power of internal leaf contents of the two foliage types. Longer‐term observation of feeding behaviour in a no‐choice situation shows no difference in meal duration, confirming the lack of difference in phagostimulatory power. However, on average, intermeal intervals are twice as long on the resistant foliage, leading to an overall lower food consumption during the assay. This result suggests an anti‐digestive or toxic effect of the resistant foliage that slows behaviour and limits food intake. Previous research has shown that waxes of the resistant foliage deter initiation of feeding by the spruce budworm and that this foliage contains higher levels of tannins and monoterpenes. The data suggest that the resistant foliage contains a post‐ingestive second line of defence against the spruce budworm.     

Characterization of microsatellite loci for the detection of temporal genetic shifts within a single cohort of the brown demoiselle,Neopomacentrus filamentosus

Neopomacentrus filamentosus, a common damselfish on the Indo–Australian archipelago, undergoes significant shifts in size and mitochondrial genetic structure upon larval settlement and metamorphosis to juvenile stages. We characterized five polymorphic microsatellite loci in order to study temporal genetic shifts within a single generation of N. filamentosus sampled first as larval settlers then again as demersal juvenile recruits. All loci were extremely polymorphic and exhibited high levels of heterozygosity. While all loci from the larval samples conformed to Hardy – Weinberg expectations, significant heterozygote deficiencies were seen in two loci in the juvenile samples, likely due to extreme size‐selective mortality imposed post‐settlement.     

Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity

International actions to combat the threat posed by invasive alien species (IAS) to crops and biodiversity have intensified in recent years. The formulation of 15 guiding principles on IAS by the Convention on Biological Diversity (CBD) stimulated the International Plant Protection Convention (IPPC) to review its role in protecting biodiversity. IPPC standards now demonstrate clearly that the risks posed by any organism that is directly or indirectly injurious to cultivated or uncultivated plants can be assessed and managed under the IPPC. Since the IPPC, unlike the CBD, constitutes an international legal instrument recognised by the World Trade Organization, greater protection from the introduction of IAS is now available. However, phytosanitary measures can only be enacted if they can be justified by risk analysis and we outline some novel strategies to improve the assessment and management of the risks posed by IAS, highlighting some of the key challenges which remain.     

Ultrastructural Damage by Cadmium in a Marine Dinoflagellate,Prorocentrum micans1

Prorocentrum micans Ehrenberg, a free-living marine dinoflagellate, was used to test the intracellular toxic action of cadmium. The cells were cultivated in Erdschreiber medium, with Cd concentrations of 10–100 ppb. Thin sections of treated cells, examined ultramicroscopically, exhibited vacuolations, increased numbers of lysosomes, and severe mitochondrial damage. The first two alterations are a general response to toxicity; the third is Cd specific. Although some chloroplasts were affected by Cd, they were not very sensitive to its action. The nuclear apparatus was not morphologically affected.     

Microsatellite markers for the whelk Buccinum undatum

Five microsatellite loci are described for the commercially exploited marine gastropod, Buccinum undatum. Levels of polymorphism were variable with three to 19 alleles per locus and expected heterozygosities of 0.26–0.94 in 60 individuals of the population from which the loci were isolated. Homozygote excess at two of the loci might be attributable to null alleles, and these loci should not be used in, for example, parentage analysis. Nevertheless, because null allele frequencies can be estimated and their effects partitioned, all are useful markers for studies of population differentiation.     

Factors affecting the microdistribution of Gammarus pulex (Amphipoda): an experimental study

SUMMARY. 1. The tnierodistribution of Gammarus species is size assortative: larger animals are associated with larger substrate particles. Using an artificial stream with scrubbed substrate we investigate the hypothesis that the assortative mechanism is stimulated by current avoidance rather than food searching.
2. In uniformly mixed substrate, G. pulex tend to move upstream, but in patchy substrate they are found in a predictable substrate grade. There is no discrimination between patches by different size classes of G. pulex in static water. The size assortative field pattern can only be reproduced under flow conditions in the laboratory. It occurs in the absence of food and irrespective of the sequence or location of substrate patches.
3. As density increases, G. pulex are displaced from the optimal patches but move into the open stream rather than into the cover of alternative patch types.
4. We discuss the significance of these results and suggest that some earlier models explaining mechanisms for microdistribution patterns tnay have been unnecessarily complex. Contrasts between natural and simulated stream situations and their experimental advantages are noted.