Microsomal and cytosolic cytochrome P450 mediated benzo(a)pyrene hydroxylation in Pleurotus pulmonarius

Summary Microsomal and soluble fractions of Pleurotus pulmonarius exhibited a reduced carbon monoxide difference spectrum with P450 maxima at 448nm and 450–452nm respectively. Substrate induced Type I spectra were observed on addition of benzo(a)pyrene to both fractions. Benzo(a)pyrene hydroxylation was measured using the aryl hydrocarbon hydroxylase assay and was observed to be P450 dependent as indicated by carbon monoxide inhibition together with the substrate binding characteristics. The activity of the fractions were observed to give K_m of 200mM and 660mM and V_max of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively.     

The Lutheran and secretor loci: genetic linkage analysis.

Linkage analysis of Lu and Se and 31 other loci indicate that Lu:Se are not closely linked to ABO, ACP1, Co, Do, Est.D,Fy, GC, Gm, GLO:HLA, GPT, Inv, Jk,K,MN,P,PGD,PGM1, Rh,Sc, UMPK OR Yt. Lod scores for 18 families informative for Lu:Se gave no evidence for sex differentiation in recombination fraction: theta for males was 0.07, and for females, .08.     

Relative positions of chromosome 1 loci Fy, PGM1, Sc, UMPK, Rh, PGD and ENO1 in man.

Ongoing linkage studies of red cell antigens and enzymes in many families along with concentration on a large Mennonite kindred segregating for Sc have resulted in lods, recombinant: nonrecombinant counts and multi-point information which support an order with approximate recombination fractions as measured in the male as follows: Fy--.25--PGM1--.20--Sc--less than .05--UMPK--.15--Rh--.20--PGD, with ENO1 close to PGD. The insertion of Sc and UMPK between PGM1 and Rh allows the recognition of double crossing-over between the latter pair; indications are that this is not a rare event in the female. In the male no evidence of double crossing-over was found in the similar distances PGM1--Rh and Sc--PGD in 13 and 19 opportunities respectively.     

Contingent absences account for range limits but not the local abundance structure of an invasive springtail

Understanding spatial variation in abundance is essential for forecasts of responses to environmental change impacts on diversity and the consequent conservation actions. However, few studies have sought to distinguish the causal basis of abundance structure and range limits. Here we do so for an invasive springtail species, Pogonognathellus flavescens, in a cold temperate island setting. Local microclimate variables and physiological tolerances of this habitat generalist suggest that it should be widely distributed across a range of habitats below 200 m elevation on the island. By contrast, island‐wide and local abundance surveys show that it is restricted to indigenous Poa cookii tussock grassland habitats in the southeast. Preference for this habitat is correlated with the presence of vertebrates and a threshold response to soil Ca and pH, with preference for low values of both. Habitat specificity may be the consequence of a founder effect because the species is characterized by only a single mitochondrial COI haplotype. Nonetheless, P. flavescens is absent from many other areas of suitable P. cookii habitat around the island. The most plausible explanation appears to be dispersal limitation (i.e. a contingent absence). Despite high locomotion speeds measured in the laboratory at optimum and mean annual soil temperatures (0.97 and 0.42 cm s^?1 at 26°C and 6.5°C, respectively), dispersal in the field indicated that >100 yr would be required to reach all available habitat in the absence of jump dispersal, for which few vectors exist. Thus, current range limits are set by dispersal limitation (i.e. contingent absences) whilst abundance structure is a function of variation in soil substrate quality. Edaphic variables both in this species and other soil invertebrates may be more significant than climatic factors in determining abundance and occurrence, indicating that they should be routinely included in species distribution models. Low genetic diversity and high habitat preference suggest that in the absence of introduction of additional individuals, the species will not spread rapidly at the island. However, over time, the widening distribution of its preferred habitat, P. cookii, as a consequence of a major management intervention (the eradication of feral cats), may enable it to colonize all suitable areas.