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Kirsi A. Virtanen Wouter D. van Marken Lichtenbelt Pirjo Nuutila 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(5):1004-1008
Human adults have functionally active BAT. The metabolic function can be reliably measured in vivo using modern imaging modalities (namely PET/CT). Cold seems to be one of the most potent stimulators of BAT metabolic activity but other stimulators (for example insulin) are actively studied. Obesity is related to lower metabolic activity of BAT but it may be reversed after successful weight reduction such as after bariatric surgery. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease. 相似文献
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Florian Villegas Daphné Lehalle Daniela Mayer Melanie Rittirsch Michael B. Stadler Marietta Zinner Daniel Olivieri Pierre Vabres Laurence Duplomb-Jego Eveline S.J.M. De Bont Yannis Duffourd Floor Duijkers Magali Avila David Geneviève Nada Houcinat Thibaud Jouan Paul Kuentz Klaske D. Lichtenbelt Joerg Betschinger 《Cell Stem Cell》2019,24(2):257-270.e8
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Mitochondrial DNAs of six morphologically different Phytophthora species were digested with 15 restriction enzymes. The numbers of restriction fragments obtained differed considerably from those theoretically expected for random base distribution. Enzymes with relatively many G and C in their recognition sequences produced significantly larger numbers of fragments. Moreover, fragments generated by most of these enzymes were more often shared by two or more species than those from enzymes with more A and T in their recognition sequence. It is concluded that base distribution in mitochondrial DNA of Phytophthora is heterogeneous,AT-rich stretches occurring scattered over the mitochondrial genome and GC-rich regions present in conserved sequences, presumably genes. A practical consequence for taxonomic RFLP studies is that optimal enzymes can be selected, depending on the desired level of resolution. 相似文献
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The 18S ribosomal RNAs of 21 tetrapods were sequenced and aligned with five
published tetrapod sequences. When the coelacanth was used as an outgroup,
Lissamphibia (living amphibians) and Amniota (amniotes) were found to be
statistically significant monophyletic groups. Although little resolution
was obtained among the lissamphibian taxa, the amniote sequences support a
sister-group relationship between birds and mammals. Portions of the 28S
ribosomal RNA (rRNA) molecule in 11 tetrapods also were sequenced, although
the phylogenetic results were inconclusive. In contrast to previous
studies, deletion or down- weighting of base-paired sites were found to
have little effect on phylogenetic relationships. Molecular evidence for
amniote relationships is reviewed, showing that three genes
(beta-hemoglobin, myoglobin, and 18S rRNA) unambiguously support a
bird-mammal relationship, compared with one gene (histone H2B) that favors
a bird- crocodilian clade. Separate analyses of four other genes (alpha-
crystallin A, alpha-hemoglobin, insulin, and 28S rRNA) and a combined
analysis of all sequence data are inconclusive, in that different groups
are defined in different analyses and none are strongly supported. It is
suggested that until sequences become available from a broader array of
taxa, the molecular evidence is best evaluated at the level of individual
genes, with emphasis placed on those studies with the greatest number of
taxa and sites. When this is done, a bird-mammal relationship is most
strongly supported. When regarded in combination with the morphological
evidence for this association, it must be considered at least as plausible
as a bird-crocodilian relationship.
相似文献
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van Marken Lichtenbelt WD Schrauwen P van De Kerckhove S Westerterp-Plantenga MS 《American journal of physiology. Endocrinology and metabolism》2002,282(5):E1077-E1083
We studied interindividual variation in body temperature and energy expenditure, the relation between these two, and the effect of mild decrease in environmental temperature (16 vs. 22 degrees C) on both body temperature and energy expenditure. Nine males stayed three times for 60 h (2000-0800) in a respiration chamber, once at 22 degrees C and twice at 16 degrees C, in random order. Twenty-four-hour energy expenditure, thermic effect of food, sleeping metabolic rate, activity-induced energy expenditure, and rectal and skin temperatures were measured. A rank correlation test with data of 6 test days showed significant interindividual variation in both rectal and skin temperatures and energy expenditures adjusted for body composition. Short-term exposure of the subjects to 16 degrees C caused a significant decrease in body temperature (both skin and core), an increase in temperature gradients, and an increase in energy expenditure. The change in body temperature gradients was negatively related to changes in energy expenditure. This shows that interindividual differences exist with respect to the relative contribution of metabolic and insulative adaptations to cold. 相似文献
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Maja Hempel Kirsten Cremer Charlotte?W. Ockeloen Klaske?D. Lichtenbelt Johanna?C. Herkert Jonas Denecke Tobias?B. Haack Alexander?M. Zink Jessica Becker Eva Wohlleber Jessika Johannsen Bader Alhaddad Rolph Pfundt Sigrid Fuchs Dagmar Wieczorek Tim?M. Strom Koen?L.I. van?Gassen Tjitske Kleefstra Christian Kubisch Hartmut Engels Davor Lessel 《American journal of human genetics》2015,97(3):493-500
CHAMP1 encodes a protein with a function in kinetochore-microtubule attachment and in the regulation of chromosome segregation, both of which are known to be important for neurodevelopment. By trio whole-exome sequencing, we have identified de novo deleterious mutations in CHAMP1 in five unrelated individuals affected by intellectual disability with severe speech impairment, motor developmental delay, muscular hypotonia, and similar dysmorphic features including short philtrum and a tented upper and everted lover lip. In addition to two frameshift and one nonsense mutations, we found an identical nonsense mutation, c.1192C>T (p.Arg398∗), in two affected individuals. All mutations, if resulting in a stable protein, are predicted to lead to the loss of the functionally important zinc-finger domains in the C terminus of the protein, which regulate CHAMP1 localization to chromosomes and the mitotic spindle, thereby providing a mechanistic understanding for their pathogenicity. We thus establish deleterious de novo mutations in CHAMP1 as a cause of intellectual disability. 相似文献
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Validation of an individualised model of human thermoregulation for predicting responses to cold air
van Marken Lichtenbelt WD Frijns AJ van Ooijen MJ Fiala D Kester AM van Steenhoven AA 《International journal of biometeorology》2007,51(3):169-179
Most computer models of human thermoregulation are population based. Here, we individualised the Fiala model [Fiala et al.
(2001) Int J Biometeorol 45:143–159] with respect to anthropometrics, body fat, and metabolic rate. The predictions of the adapted
multisegmental thermoregulatory model were compared with measured skin temperatures of individuals. Data from two experiments,
in which reclining subjects were suddenly exposed to mild to moderate cold environmental conditions, were used to study the
effect on dynamic skin temperature responses. Body fat was measured by the three-compartment method combining underwater weighing
and deuterium dilution. Metabolic rate was determined by indirect calorimetry. In experiment 1, the bias (mean difference)
between predicted and measured mean skin temperature decreased from 1.8°C to −0.15°C during cold exposure. The standard deviation
of the mean difference remained of the same magnitude (from 0.7°C to 0.9°C). In experiment 2 the bias of the skin temperature
changed from 2.0±1.09°C using the standard model to 1.3±0.93°C using individual characteristics in the model. The inclusion
of individual characteristics thus improved the predictions for an individual and led to a significantly smaller systematic
error. However, a large part of the discrepancies in individual response to cold remained unexplained. Possible further improvements
to the model accomplished by inclusion of more subject characteristics (i.e. body fat distribution, body shape) and model
refinements on the level of (skin) blood perfusion, and control functions, are discussed. 相似文献