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Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
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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 Km of 200mM and 660mM and Vmax of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively. 相似文献
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Mark Richard McNeill Chikako van Koten Stephen Latham Goldson 《Journal of Applied Entomology》2021,145(6):587-600
Listronotus bonariensis (Kuschel) is a pest of agriculturally important graminaceous species, with mining larvae that kill the stems of the host plants. In this study, larval populations were measured in spring and summer in irrigated dairy grassland comprising Lolium perenne L. (cv. Nui) with and without the endophyte Epichloë festucae var. lolii Latch, M.J. Chr. and Samuels and Poa annua L.. Larvae were extracted from tillers taken from the swards of these two grass species and extracted from turves, and L. bonariensis population densities were estimated from tiller and turf larval counts on a m−2 basis. Over the study period, the total number of larvae and larval densities extracted from turves was on average 2× greater than indicated from tillers. In most seasons, larval densities from turves were significantly higher than those from the tillers, though there was no correlation between tiller and turf larval densities. Mean head capsule widths of larvae emerging from turf samples showed significant seasonal effects compared with tillers, while mean head capsule widths of all four instars were significantly greater when extracted from tillers compared with turves. There was a significant endophyte effect on head capsule widths of larvae collected in summer, but the effect was not consistent across instars or source. Conversely, no significant endophyte effect on head capsule width was found in spring populations from either tillers or turves. This study shows that in irrigated dairy pasture, a high proportion of L. bonariensis larvae can live externally of tillers, presumably among the organic matter around the base of grasses in irrigated dairy pasture, and that density estimates based only on tiller populations will have significantly underestimated actual numbers. Having a precise indication of larval population densities is essential when developing life tables or determining economic damage threshold levels. 相似文献
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Garcia-Conesa MT Crepin VF Goldson AJ Williamson G Cummings NJ Connerton IF Faulds CB Kroon PA 《Journal of biotechnology》2004,108(3):227-241
Several extracellular feruloyl esterases were produced by the mesophilic fungus Talaromyces stipitatus when grown on selective carbon sources in liquid media. Type-A and Type-B feruloyl esterases, as defined by their substrate specificity against methyl hydroxycinnamates, were produced during growth on wheat bran and sugar beet pulp, respectively. In addition, Tal. stipitatus produced a new type of esterase (TsFaeC) during growth on sugar beet pulp with a broader spectrum of activity (Type-C) against the (hydroxy)cinnamate esters than those previously described. All three enzymes were purified and N-terminal amino acid sequences and internal peptide sequences determined. The TsFaeC sequences were used to amplify a gene fragment from Tal. stipitatus genomic DNA. The flanking sequences were identified with the aid of RACE-RTPCR, and a full-length clone constructed. The faeC gene is present as a single copy and contains a single intron. The complete cDNA fragment contains an ORF of 1590bp, faeC, which is predicted to encode a 530 amino acid pre-protein, including a 25-residue signal peptide, and to produce a mature protein of M(R) 55 340Da. There was no evidence for a carbohydrate-binding domain in TsFaeC. 相似文献
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Out of Africa and back again: nested cladistic analysis of human Y chromosome variation 总被引:18,自引:3,他引:15
Hammer MF; Karafet T; Rasanayagam A; Wood ET; Altheide TK; Jenkins T; Griffiths RC; Templeton AR; Zegura SL 《Molecular biology and evolution》1998,15(4):427-441
We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544
individuals from Africa, Asia, Europe, Oceania, and the New World.
Phylogenetic analyses of these nine sites resulted in a tree for 10
distinct Y haplotypes with a coalescence time of approximately 150,000
years. The 10 haplotypes were unevenly distributed among human populations:
5 were restricted to a particular continent, 2 were shared between Africa
and Europe, 1 was present only in the Old World, and 2 were found in all
geographic regions surveyed. The ancestral haplotype was limited to African
populations. Random permutation procedures revealed statistically
significant patterns of geographical structuring of this paternal genetic
variation. The results of a nested cladistic analysis indicated that these
geographical associations arose through a combination of processes,
including restricted, recurrent gene flow (isolation by distance) and range
expansions. We inferred that one of the oldest events in the nested
cladistic analysis was a range expansion out of Africa which resulted in
the complete replacement of Y chromosomes throughout the Old World, a
finding consistent with many versions of the Out of Africa Replacement
Model. A second and more recent range expansion brought Asian Y chromosomes
back to Africa without replacing the indigenous African male gene pool.
Thus, the previously observed high levels of Y chromosomal genetic
diversity in Africa may be due in part to bidirectional population
movements. Finally, a comparison of our results with those from nested
cladistic analyses of human mtDNA and beta-globin data revealed different
patterns of inferences for males and females concerning the relative roles
of population history (range expansions) and population structure
(recurrent gene flow), thereby adding a new sex-specific component to
models of human evolution.
相似文献
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JG Hansen W Gao J Dupuis GT O’Connor W Tang M Kowgier A Sood SA Gharib LJ Palmer M Fornage SR Heckbert BM Psaty SL Booth SUNLIGHT Consortium Patricia A Cassano 《Respiratory research》2015,16(1)
Background
Vitamin D is associated with lung function in cross-sectional studies, and vitamin D inadequacy is hypothesized to play a role in the pathogenesis of chronic obstructive pulmonary disease. Further data are needed to clarify the relation between vitamin D status, genetic variation in vitamin D metabolic genes, and cross-sectional and longitudinal changes in lung function in healthy adults.Methods
We estimated the association between serum 25-hydroxyvitamin D [25(OH)D] and cross-sectional forced expiratory volume in the first second (FEV1) in Framingham Heart Study (FHS) Offspring and Third Generation participants and the association between serum 25(OH)D and longitudinal change in FEV1 in Third Generation participants using linear mixed-effects models. Using a gene-based approach, we investigated the association between 241 SNPs in 6 select vitamin D metabolic genes in relation to longitudinal change in FEV1 in Offspring participants and pursued replication of these findings in a meta-analyzed set of 4 independent cohorts.Results
We found a positive cross-sectional association between 25(OH)D and FEV1 in FHS Offspring and Third Generation participants (P = 0.004). There was little or no association between 25(OH)D and longitudinal change in FEV1 in Third Generation participants (P = 0.97). In Offspring participants, the CYP2R1 gene, hypothesized to influence usual serum 25(OH)D status, was associated with longitudinal change in FEV1 (gene-based P < 0.05). The most significantly associated SNP from CYP2R1 had a consistent direction of association with FEV1 in the meta-analyzed set of replication cohorts, but the association did not reach statistical significance thresholds (P = 0.09).Conclusions
Serum 25(OH)D status was associated with cross-sectional FEV1, but not longitudinal change in FEV1. The inconsistent associations may be driven by differences in the groups studied. CYP2R1 demonstrated a gene-based association with longitudinal change in FEV1 and is a promising candidate gene for further studies.Electronic supplementary material
The online version of this article (doi:10.1186/s12931-015-0238-y) contains supplementary material, which is available to authorized users. 相似文献8.
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Federico Tomasetto Silvio Cianciullo Marco Reale Fabio Attorre Oluwashola Olaniyan Stephen L. Goldson 《BioControl》2018,63(4):521-531
Earlier study at a national scale has shown that insect pests in agriculture can develop resistance to natural enemies following ongoing expansion and simplification of agricultural systems. Here, we used 25 years of field-sampling data segmented into three distinct ecoregions in New Zealand to show that parasitism rate of a key pasture pest (Listronotus bonariensis, Argentine stem weevil) by the introduced parasitoid Microctonus hyperodae has significantly declined. However, this decline has not happened simultaneously in all three ecoregions but with a one year time-lag. The variation in parasitism rate trends might be attributed to subsets of the weevil populations that became resistant to their biocontrol agent once having been exposed to seven years selection pressure (ca. 14 generations) since the parasitoid releases. This result supports the hypothesis that adaptation leading to resistance might have similarly occurred in different parts of the country indicating that the genetic variation needed for the acquisition of resistance was equally present everywhere. 相似文献
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Mark R McNeill Toni M Withers Stephen L Goldson 《Australian Journal of Entomology》2005,44(2):201-207
Abstract Cleopus japonicus Wingelmüller (Coleoptera: Curculionidae) is being considered for release to control buddleia Buddleja davidii in New Zealand. As part of the pre-release testing, Moroccan and Irish biotypes of the solitary endoparasitoid Microctonus aethiopoides Loan (Hymenoptera: Braconidae) were evaluated for potential non-target impacts on adult C. japonicus should release occur. Laboratory experiments evaluated both the behavioural and physiological suitability of C. japonicus to both biotypes of the parasitoid. Parasitoid behavioural attraction was assessed using the pathenogenic bacterium Serratia marcescens (Enterobactereaceae), as an indicator of ovipositor penetration. Physiological suitability was assessed by comparing parasitism of C. japonicus with the natural hosts of the respective parasitoid biotypes. The parasitoid-bacteria study showed that C. japonicus was behaviourally acceptable to both Moroccan and Irish M. aethiopoides , with the two experiments producing 34% and 8% mortality, respectively. Cleopus japonicus did not support development of either Moroccan or Irish M. aethiopoides biotypes. None of the weevils dissected at the end of the experiment contained immature parasitoids. Comparison between unexposed and parasitoid-exposed C. japonicus found no difference in premature mortality during the experiment nor in the number of fully reproductive females at its conclusion. The results of this study predict that should C. japonicus be released, the potential impact of M. aethiopoides on field populations will be negligible. 相似文献