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461.
W E Nance J Bodurtha L J Eaves J Hewitt H Maes J Segrest J Meyer M Neale R Schieken 《Twin research》1998,1(1):3-8
Models are presented for the analysis of longitudinal data from same-age twins which permit the exploration of a remarkably diverse array of alternative explanations for continuity and change during development. Data of this type permit the detection of new sources of genetic or environmental covariation during development that are not expressed at earlier ages and, because they include the effects of age-specific genes, the resulting heritability estimates are more reliable than those obtained from relatives who differ in age. The proposed models were applied to measurements of HDL cholesterol obtained on 81 pairs of monozygotic (MZ) twins and 69 dizygotic (DZ) pairs at 11, 12.5 and 14 years of age. All three MZ co-twin correlations were substantially higher than the self correlations across occasions, suggesting that new sources of genetic or environmental covariation must be expressed during early adolescence. This interpretation was confirmed by analysis of the full covariance matrices which showed that only models which assumed the expression of new or age-specific genes could explain the observed pattern of covariation. Because they include the effects of age-specific genes, the resulting heritabilities (0.80-0.83) were substantially higher than many previous estimates. 相似文献
462.
During a 1993 austral spring cruise, a complex biomass was encounterednear South Orkney Island that ranged from a low-biomass, Chaetocerostortissimus assemblage south of the front towards the ice edge,to a high-biomass, Thalassiosira gravida-dominated assemblageat the northern edge. The maximum levels of chlorophyll (Chl)a (up to 6 mg m3) were higher than those observed inprevious high-performance liquid chromatography-based studiesof pigments in the pelagic Southern Ocean. The non-photosyntheticpigment chlorophyllide a comprised up to 75% of the chlorophyllouspigments in the southern assemblage, but < 5% in the northernassemblage. Concentrations of the xanthophylls diadinoxanthin(DD) and diatoxanthin (DT), used as indicators of mean irradiance,indicated low-light-adapted populations. Low-light DD + DT/Chla ratios in surface waters indicated that vertical mixing limitedphytoplankton residence time in the near-surface layer, andthus limited exposure to maximum irradiance. Deck incubationsof natural assemblages indicated that the dark epoxidation reaction(i.e. the return of DT to DD) was a two-step reaction with theinitial rate being more rapid (t1/2 = 9.5 min) than the second(t1/2 = 55 min). Fucoxanthin, a major diatom pigment, was morestable chemically in the water column than Chl a, and the verticalprofiles of fucoxanthin followed those of chlorophyllide a insome cases. The formation and apparent stability of chlorophyllidea and fucoxanthin are important considerations when estimatingphotosynthetically active biomass over large regions of theocean. 相似文献
463.
Sewell MM Davis MF Tuskan GA Wheeler NC Elam CC Bassoni DL Neale DB 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):214-222
Chemical wood property traits were analyzed for the presence of quantitative trait loci (QTLs) in a three-generation outbred
pedigree of loblolly pine (Pinus taeda L.). These traits were assayed using pyrolysis molecular beam mass spectrometry and include mass spectrum peak intensities
associated with carbohydrates, α-cellulose and hemicellulose sugars, and lignin. Models for projection to latent structures
(PLS) were used to also estimate the chemical composition of cell walls (i.e., α-cellulose, galactan and lignin) from mass
spectrum data using multivariate regression. Both earlywood and latewood fractions from the fifth annual ring were analyzed
for each trait. An interval mapping approach designed for an outbred pedigree was used to estimate the number of QTLs, the
magnitude of QTL effects, and their genomic position. Eight unique QTLs influencing cell wall chemistry were detected from
multiple peak intensities and/or PLS estimates using the one- and two-QTL models. Significant differences in chemical contents
were observed among the populations from North Carolina vs Oklahoma, and results from QTL×environment analyses suggest that
QTLs interact with environmental location. QTLs should be verified in larger experiments and in different genetic and environmental
backgrounds. QTL mapping will help towards eventually identifying genes having a major effect on chemical wood properties.
Received: 19 January 2001 / Accepted: 31 May 2001 相似文献
464.
Sequencing chromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries 总被引:1,自引:0,他引:1
Talkowski ME Rosenfeld JA Blumenthal I Pillalamarri V Chiang C Heilbut A Ernst C Hanscom C Rossin E Lindgren AM Pereira S Ruderfer D Kirby A Ripke S Harris DJ Lee JH Ha K Kim HG Solomon BD Gropman AL Lucente D Sims K Ohsumi TK Borowsky ML Loranger S Quade B Lage K Miles J Wu BL Shen Y Neale B Shaffer LG Daly MJ Morton CC Gusella JF 《Cell》2012,149(3):525-537
Balanced chromosomal abnormalities (BCAs) represent a relatively untapped reservoir of single-gene disruptions in neurodevelopmental disorders (NDDs). We sequenced BCAs in patients with autism or related NDDs, revealing disruption of 33 loci in four general categories: (1) genes previously associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, and CDKL5), (2) single-gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, and SNURF-SNRPN), (3) novel risk loci (e.g., CHD8, KIRREL3, and ZNF507), and (4) genes associated with later-onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, and ANK3). We also discovered among neurodevelopmental cases a profoundly increased burden of copy-number variants from these 33 loci and?a significant enrichment of polygenic risk alleles from genome-wide association studies of autism and schizophrenia. Our findings suggest a polygenic risk model of autism and reveal that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages. 相似文献
465.
466.
Diurnal series of fluorescence and photosynthesis assays wereconducted in high altitude (3803 m), tropical (16°), LakeTiticaca (Peru/Bolivia). Near-surface diurnal thermoclines formedon typical days of high photon flux density (PFD, {small tilde}2000 µE m2 s1). In the depth range of diurnalstratification profiles of in vivo fluorescence, both without(Fa and with (Fb DCMU, exhibited a mean decrease of 64% frommorning to mid-day, but little change (mean increase of 1.5%)through the afternoon. Three times during the day surface, mid-depth(35 m) and deep (1520 m) phytoplankton sampleswere incubated with H14CO3 under short (<2 h) exposuresto a range of in situ PFDs. Comparison of phytoplankton in differentsamples (ANOVA) showed identical photosynthetic response insunrise (isothermal) samples but a significant drop in surfaceand mid-depth photosynthesis at all PFDs during times of diurnalstratification. Similarly, both low-light () and light-saturated(P2 max photosynthetic parameters were lower in mid-day surfacesamples compared to deep samples. In addition, previously photoinhibitedsamples had a higher threshold intensity for photoinhibition,IT. These results, together with diurnal time series of fluorescencefrom in situ incubations, demonstrate that recovery from extendedepisodes of photoinhibition during diurnal stratification isslower than suggested by previous observations in vitro. Photosynthesisby near-surface phytoplankton is different in light increasingup to IT than light decreasing from IT. This effect can be modeledby reducing and Pmax as a function of the maximum photoinhibitingPFD in the diurnal light history.
1Present address: Division of Molecular Plant Biology, Universityof California, Berkeley, Berkeley, CA 94720, USA 相似文献
467.
Zili Wang M. Neale Weitzmann Sreedhara Sangadala William C. Hutton S. Tim Yoon 《The Journal of biological chemistry》2013,288(39):28243-28253
468.
Inhibition by ultraviolet and photosynthetically available radiation lowers model estimates of depth‐integrated picophytoplankton photosynthesis: global predictions for Prochlorococcus and Synechococcus 下载免费PDF全文
Phytoplankton photosynthesis is often inhibited by ultraviolet (UV) and intense photosynthetically available radiation (PAR), but the effects on ocean productivity have received little consideration aside from polar areas subject to periodic enhanced UV‐B due to depletion of stratospheric ozone. A more comprehensive assessment is important for understanding the contribution of phytoplankton production to the global carbon budget, present and future. Here, we consider responses in the temperate and tropical mid‐ocean regions typically dominated by picophytoplankton including the prokaryotic lineages, Prochlorococcus and Synechococcus. Spectral models of photosynthetic response for each lineage were constructed using model strains cultured at different growth irradiances and temperatures. In the model, inhibition becomes more severe once exposure exceeds a threshold (Emax) related to repair capacity. Model parameters are presented for Prochlorococcus adding to those previously presented for Synechococcus. The models were applied to estimate midday, water column photosynthesis based on an atmospheric model of spectral radiation, satellite‐derived spectral water transparency and temperature. Based on a global survey of inhibitory exposure severity, a full‐latitude section of the mid‐Pacific and near‐equatorial region of the east Pacific were identified as representative regions for prediction of responses over the entire water column. Comparing predictions integrated over the water column including versus excluding inhibition, production was 7–28% lower due to inhibition depending on strain and site conditions. Inhibition was consistently greater for Prochlorococcus compared to two strains of Synechococcus. Considering only the surface mixed layer, production was inhibited 7–73%. On average, including inhibition lowered estimates of midday productivity around 20% for the modeled region of the Pacific with UV accounting for two‐thirds of the reduction. In contrast, most other productivity models either ignore inhibition or only include PAR inhibition. Incorporation of Emax model responses into an existing spectral model of depth‐integrated, daily production will enable efficient global predictions of picophytoplankton productivity including inhibition. 相似文献
469.
Toshimitsu Fukiharu Neale L. Bougher Peter K. Buchanan Akira Suzuki Chihiro Tanaka Naohiko Sagara 《Mycoscience》2011,52(2):137-142
A new ammonia fungus, Coprinopsis austrophlyctidospora, is described from Nothofagus and Pinus forests in New Zealand and from Eucalyptus forest in Australia. In ecology and macro-morphology, this species is similar to the Northern Hemisphere species C. phlyctidospora, but the new species differs in morphological characters of the basidiospore, i.e., in having a plage, more minute surface
warts, and the smaller size of the basidiospore. 相似文献
470.
Banerji S Ngo M Lane CF Robinson CA Minogue S Ridgway ND 《Molecular biology of the cell》2010,21(23):4141-4150
Cholesterol and sphingomyelin (SM) associate in raft domains and are metabolically coregulated. One aspect of coordinate regulation occurs in the Golgi apparatus where oxysterol binding protein (OSBP) mediates sterol-dependent activation of ceramide transport protein (CERT) activity and SM synthesis. Because CERT transfer activity is dependent on its phosphatidylinositol 4 phosphate [PtdIns(4)P]-specific pleckstrin homology domain, we investigated whether OSBP activation of CERT involved a Golgi-associated PtdIns 4-kinase (PI4K). Cell fractionation experiments revealed that Golgi/endosome-enriched membranes from 25-hydroxycholesterol-treated Chinese hamster ovary cells had increased activity of a sterol-sensitive PI4K that was blocked by small interfering RNA silencing of OSBP. Consistent with this sterol-requirement, OSBP silencing also reduced the cholesterol content of endosome/trans-Golgi network (TGN) fractions containing PI4KIIα. PI4KIIα, but not PI4KIIIβ, was required for oxysterol-activation of SM synthesis and recruitment of CERT to the Golgi apparatus. However, neither PI4KIIα nor PI4KIIIβ expression was required for 25-hydroxycholesterol-dependent translocation of OSBP to the Golgi apparatus. The presence of OSBP, CERT, and PI4KIIα in the TGN of oxysterol-stimulated cells suggests that OSBP couples sterol binding or transfer activity with regulation of PI4KIIα activity, leading to CERT recruitment to the TGN and increased SM synthesis. 相似文献