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101.
Expression of lauroyl-acyl carrier protein thioesterase in brassica napus seeds induces pathways for both fatty acid oxidation and biosynthesis and implies a set point for triacylglycerol accumulation 总被引:1,自引:0,他引:1
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Expression of a California bay lauroyl-acyl carrier protein thioesterase (MCTE) in developing seeds of transgenic oilseed rape alters the fatty acid composition of the mature seed, resulting in up to 60 mol% of laurate in triacylglycerols. In this study, we examined the metabolism of lauric acid and 14C-acetate in developing seeds of oilseed rape that express high levels of MCTE. Lauroyl-CoA oxidase activity but not palmitoyl-CoA oxidase activity was increased several-fold in developing seeds expressing MCTE. In addition, isocitrate lyase and malate synthase activities were six- and 30-fold higher, respectively, in high-laurate developing seeds. Control seeds incorporated 14C-acetate almost entirely into fatty acids, whereas in seeds expressing MCTE, only 50% of the label was recovered in lipids and the remainder was in a range of water-soluble components, including sucrose and malate. Together, these results indicate that the pathways for beta-oxidation and the glyoxylate cycle have been induced in seeds expressing high levels of MCTE. Although a substantial portion of the fatty acid produced in these seeds is recycled to acetyl-CoA and sucrose through the beta-oxidation and glyoxylate cycle pathways, total seed oil is not reduced. How is oil content maintained if lauric acid is inefficiently converted to triacylglycerol? The levels of acyl carrier protein and several enzymes of fatty acid synthesis were increased two- to threefold at midstage development in high-laurate seeds. These results indicate that a coordinate induction of the fatty acid synthesis pathway occurs, presumably to compensate for the lauric acid lost through beta-oxidation or for a shortage of long-chain fatty acids. 相似文献
102.
G A Dunaway G L Leung M D Cooper J R Thrasher S R Wagle 《Biochemical and biophysical research communications》1978,80(1):71-74
The distribution profile of the isozymes of phosphofructokinase (PFK) in different cell types of rat liver is established using the techniques of electrophoresis and immunodiffusion. Agarose gel electrophoresis of the extracts of parenchymal cells, Kupffer or sinusoidal cells, and whole liver indicated that two PFK isozymes are present in whole liver and that the faster moving hepatic PFK isozyme is present only in parenchymal cells; whereas, the slower moving hepatic PFK isozyme is only in sinusoidal cells. Immunodiffusion studies using antiserum specific for the major hepatic PFK isozyme (PFK-L2) revealed that PFK-L2 is present only in whole liver or parenchymal cell extracts and is absent from sinusoidal cells. It is apparent that the other hepatic PFK isozyme (PFK-L1) is normally found only in sinusoidal cells. 相似文献
103.
The sites of cell proliferation and the duration of the S-phases in epithelia (tongue, stomach, duodenum, jejunum, ileum and descending colon) of the pouchless opossum, Marmosamitis , have been studied following the injection of tritiated thymidine. the sites of cell proliferation in these epithelia are not significantly different than those reported for rodent tissues. On the other hand, measurements of the mean duration of DNA synthesis revealed great variability in this phase: tongue (12.8 hr), stomach (>14.0 hr), duodenum (8.5 hr), jejunum (8.6 hr), ileum (9.7 hr) and descending colon (11-3 hr). In addition, the values obtained for the mean duration of t2 (G2 +2 /1 M) are fairly constant among the various epithelia. It is concluded that the times obtained for the average duration of the S-phases are longer and more variable in M. mitis than similar observations reported on renewing epithelia of eutherian mammals. 相似文献
104.
G A Dunaway D Naqui D Kruep J R Thrasher H P Morris 《Archives of biochemistry and biophysics》1981,212(1):1-8
The spin-lattice relaxation rate of solvent protons in suspensions of chloroplast thylakoid membranes undergoes a large transient depression following illumination in white light. This change appears to require the presence of chelatable paramagnetic ions; it is absent in chloroplasts exposed to 1 mm EDTA during the homogenization step of the isolation procedure, but reappears when 50 μm MnCl2 is added to these suspensions. Conditions that inhibit light-induced R1 changes are (i) anaerobiosis, (ii) inhibition of plastocyanin function byHg+2/CN, and (iii) the presence of superoxide dismutase. These observations suggest that chemical oxidation of nonfunctional Mn (II) by superoxide ion, which is generated under aerobic conditions by autooxidizable acceptors of Photosystem I, is responsible for the phenomenon. This interpretation was confirmed by experiments involving superoxide generation in the dark, using the NADPH-driven diaphorase activity of ferredoxin-NADP-reductase with benzylviologen as an autooxidizable acceptor. 相似文献
105.
Persistence of native and exotic plants 10 years after prairie reconstruction 总被引:1,自引:0,他引:1
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Diane L. Larson JB Bright Pauline Drobney Jennifer L. Larson Sara Vacek 《Restoration Ecology》2017,25(6):953-961
Prairie reconstructions are a critical component of preservation of the imperiled tallgrass prairie ecosystem in the Midwestern United States. Sustainability of this endeavor depends on establishment of persistent cover of planted native species and resistance to noxious weeds. The goal of this study was to understand the influence of early reconstruction practices on long‐term outcomes. Twelve replicates of three planting methods (dormant‐season broadcast, growing‐season broadcast, and growing‐season drill) and three seed mix richness levels (10, 20, or 34 species), fully crossed in a completely randomized design were planted in 2005 on nine former agricultural fields located in Iowa and Minnesota. Cover by species was estimated in 2005–2007, 2010, and 2015. In 2015, cover of planted species, native nonplanted species, and exotic species were similar to those recorded in 2010. Cover of the noxious weed Cirsium arvense had also declined by an average of 49% without herbicide from a peak in 2007 to low stable levels from 2010 to 2015. Richness of planted forbs, on the other hand, were still increasing in high‐richness broadcast treatments (e.g. 17–59% increase 2010–1015 in Minnesota). Two results in 2015 are reasons for concern: cover of planted species is only slightly over 50% in both Minnesota and Iowa, though with forbs still increasing, this may improve; and the cool‐season exotic grasses Poa pratensis and Bromus inermis are increasing at both Minnesota and Iowa sites. Control of these invasive grasses will be necessary, but care will be needed to avoid negative impacts of control methods on natives. 相似文献
106.
Multiple hypotheses explain variation in extra‐pair paternity at different levels in a single bird family
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Lyanne Brouwer Martijn van de Pol Nataly Hidalgo Aranzamendi Glen Bain Daniel T. Baldassarre Lesley C. Brooker Michael G. Brooker Diane Colombelli‐Négrel Erik Enbody Kurt Gielow Michelle L. Hall Allison E. Johnson Jordan Karubian Sjouke A. Kingma Sonia Kleindorfer Marina Louter Raoul A. Mulder Anne Peters Stephen Pruett‐Jones Keith A. Tarvin Derrick J. Thrasher Claire W. Varian‐Ramos Michael S. Webster Andrew Cockburn 《Molecular ecology》2017,26(23):6717-6729
Extra‐pair paternity (EPP), where offspring are sired by a male other than the social male, varies enormously both within and among species. Trying to explain this variation has proved difficult because the majority of the interspecific variation is phylogenetically based. Ideally, variation in EPP should be investigated in closely related species, but clades with sufficient variation are rare. We present a comprehensive multifactorial test to explain variation in EPP among individuals in 20 populations of nine species over 89 years from a single bird family (Maluridae). Females had higher EPP in the presence of more helpers, more neighbours or if paired incestuously. Furthermore, higher EPP occurred in years with many incestuous pairs, populations with many helpers and species with high male density or in which males provide less care. Altogether, these variables accounted for 48% of the total and 89% of the interspecific and interpopulation variation in EPP. These findings indicate why consistent patterns in EPP have been so challenging to detect and suggest that a single predictor is unlikely to account for the enormous variation in EPP across levels of analysis. Nevertheless, it also shows that existing hypotheses can explain the variation in EPP well and that the density of males in particular is a good predictor to explain variation in EPP among species when a large part of the confounding effect of phylogeny is excluded. 相似文献
107.
Endocrine components of body fluid homeostasis 总被引:1,自引:0,他引:1
D J Ramsay T N Thrasher P Bie 《Comparative biochemistry and physiology. A, Comparative physiology》1988,90(4):777-780
1. Linear relationships between plasma osmolality and thirst and vasopressin secretion are described in conscious dogs. 2. During water deprivation, natriuresis occurs which ameliorates the rise in plasma osmolality. 3. Increases in plasma osmolality prevent the stimulation of aldosterone secretion by angiotensin II. 相似文献
108.
Indicators of temperament appear early in infancy and remain relatively stable over time. Despite a great deal of interest in biological indices of temperament, most studies of infant temperament rely on parental reports or behavioral tasks. Thus, the extent to which commonly used temperament measures relate to potential biological indicators of infant temperament is still relatively unknown. The current experiment examines the relationship between a common parental report measure of temperament--the Infant Behavior Questionnaire-Revised (IBQ-R)--and measures of frontal EEG asymmetry in infants. We examined associations between the subscales of the IBQ-R and frontal EEG asymmetry scores recorded during a combined series of neutral attentional and putatively emotional recording conditions in infants between 7 and 9 months of age. We predicted that approach-related subscales of the IBQ-R (e.g., Approach, Soothability) would be related to greater left prefrontal asymmetry, while withdrawal-related subscales (e.g., Distress to Limitations, Fear, Falling Reactivity, Perceptual Sensitivity) would be related to greater right prefrontal asymmetry. In the mid- and lateral-frontal regions, Approach, Distress to Limitations, Fear, Soothability, and Perceptual Sensitivity were generally associated with greater left frontal activation (rs≥.23, ps<0.05), while only Falling Reactivity was associated with greater right frontal activation (rs≤-.44, ps<0.05). Results suggest that variability in frontal EEG asymmetry is robustly associated with parental report measures of temperament in infancy. 相似文献
109.
JB Farinha DL Dos Santos G Bresciani LF Bard F de Mello ST Stefanello AA Courtes FAA Soares 《Biology of sport / Institute of Sport》2015,32(2):109-114
The aim of this study was to investigate the impact of moderate aerobic training on functional, anthropometric, biochemical, and health-related quality of life (HRQOL) parameters on women with metabolic syndrome (MS). Fifteen untrained women with MS performed moderate aerobic training for 15 weeks, without modifications of dietary behaviours. Functional, anthropometric, biochemical, control diet record and HRQOL parameters were assessed before and after the training. Despite body weight maintenance, the patients presented decreases in waist circumference (P = 0.001), number of MS components (P = 0.014), total cholesterol (P = 0.049), HDL cholesterol (P = 0.004), LDL cholesterol (P = 0.027), myeloperoxidase activity (P = 0.002) and thiobarbituric acid-reactive substances levels (P = 0.006). There were no differences in total energy, carbohydrate, protein and lipid intake pre- and post-training. Furthermore, improvements in the HRQOL subscales of physical functioning (P = 0.03), role-physical (P = 0.039), bodily pain (P = 0.048), general health (P = 0.046) and social functioning scoring (P = 0.011) were reported. Despite the absence of weight loss, aerobic training induced beneficial effects on functional, anthropometric, biochemical and HRQOL parameters in women with MS. 相似文献
110.
Fellow travellers: a concordance of colonization patterns between mice and men in the North Atlantic region 总被引:1,自引:0,他引:1
EP Jones K Skirnisson TH McGovern MTP Gilbert E Willerslev JB Searle 《BMC evolutionary biology》2012,12(1):1-8