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321.
Mary J Beilby Christina E Turi Teesha C Baker Fiona JM Tymm Susan J Murch 《Plant signaling & behavior》2015,10(11)
Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to “light on.” The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The “dark” IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways. 相似文献
322.
Norimah AK H. C. Koo Hamid Jan JM Mohd Nasir MT S. Y. Tan Mahendran Appukutty Nurliyana AR Frank Thielecke Sinead Hopkins M. K. Ong C. Ning E. S. Tee 《PloS one》2015,10(10)
Background
Diets rich in whole grain are associated with several health benefits. Little is known however, about whole grain consumption patterns in Malaysia. The aim of this study was to assess whole grain intakes and dietary source in Malaysian children and adolescents.Methods
This analysis is from the MyBreakfast study, a national cross sectional study investigating eating habits among primary and secondary school children throughout Malaysia, conducted in 2013. Children (n = 5,165) and adolescents (n = 2,947) who completed two days of dietary assessment using a food record or recall respectively were included. The whole grain content of foods was estimated mainly through the use of quantitative ingredient declarations on food labels. All wholegrain foods were considered irrespective of the amount of whole grain they contained.Results
Overall, only 25% of children and 19% of adolescents were wholegrain consumers. Mean daily intakes in the total sample were 2.3g/d (SD 5.8g/d) in children and 1.7g/d (SD 4.7g/d) in adolescents and in the consumer’s only sample, mean intakes reached 9.1g/d (SD 8.6) and 9.2g/d (SD 7.1g/d) respectively. Wheat was the main grain source of whole grain while ready to eat breakfast cereals and hot cereals were the main food contributors. Less than 3% of the children and adolescents reached the US quantitative whole grain recommendation of 48g/day.Conclusion
Whole grain is consumed by only a minority of Malaysian children and adolescents and even among consumers, intakes are well below recommendations. Efforts are needed to firstly understand the barriers to whole grain consumption among Malaysian children in order to design effective health promotion initiatives to promote an increase in whole grain consumption. 相似文献323.
324.
Molecular coevolution among cryptically simple expansion segments of eukaryotic 26S/28S rRNAs 总被引:16,自引:4,他引:12
The set of "expansion segments" of any eukaryotic 26S/28S ribosomal RNA
(rRNA) gene is responsible for the bulk of the difference in length between
the prokaryotic 23S rRNA gene and the eukaryotic 26S/28S rRNA gene. The
expansion segments are also responsible for interspecific fluctuations in
length during eukaryotic evolution. They show a consistent bias in base
composition in any species; for example, they are AT rich in Drosophila
melanogaster and GC rich in vertebrate species. Dot-matrix comparisons of
sets of expansion segments reveal high similarities between members of a
set within any 28S rRNA gene of a species, in contrast to the little or
spurious similarity that exists between sets of expansion segments from
distantly related species. Similarities among members of a set of expansion
segments within any 28S rRNA gene cannot be accounted for by their
base-compositional bias alone. In contrast, no significant similarity
exists within a set of "core" segments (regions between expansion segments)
of any 28S rRNA gene, although core segments are conserved between species.
The set of expansion segments of a 26S/28S gene is coevolving as a unit in
each species, at the same time as the family of 28S rRNA genes, as a whole,
is undergoing continual homogenization, making all sets of expansion
segments from all ribosomal DNA (rDNA) arrays in a species similar in
sequence. Analysis of DNA simplicity of 26S/28S rRNA genes shows a direct
correlation between significantly high relative simplicity factors (RSFs)
and sequence similarity among a set of expansion segments. A similar
correlation exists between RSF values, overall rDNA lengths, and the
lengths of individual expansion segments. Such correlations suggest that
most length fluctuations reflect the gain and loss of simple sequence
motifs by slippage-like mechanisms. We discuss the molecular coevolution of
expansion segments, which takes place against a background of slippage-like
and unequal crossing-over mechanisms of turnover that are responsible for
the accumulation of interspecific differences in rDNA sequences.
相似文献
325.
326.
E. Longo J. B. Velázquez C. Sieiro J. Cansado P. Calo T. G. Villa 《World journal of microbiology & biotechnology》1992,8(5):539-541
Fourteen strains of the yeastSaccharomyces cerevisiae were isolated from three wineries in the Salnés wine region (N.W. Spain) at the three different periods of the natural fermentation. Each wild yeast was screened for production of acetaldehyde, ethyl acetate, isobutanol,n-propanol, amylic alcohol and other important enological compounds during laboratory scale fermentations of grape juice. After 25 days at 20°C, the analytical results evidenced variations in the production of acetaldehyde (from 13.1 to 24.3 mg/l), isobutanol (from 27.7 to 51.1 mg/l), amyl alcohols (from 111 to 183 mg/l) and ethyl acetate (from 19.3 to 43.7 mg/l). Although isolated from the same wine region, differences in the wine composition were observed depending on the particular yeast strain used for the vinification experiments. 相似文献
327.
Partial 18S rRNA sequences of five chelicerate arthropods plus a
crustacean, myriapod, insect, chordate, echinoderm, annelid, and
platyhelminth were compared. The sequence data were used to infer phylogeny
by using a maximum-parsimony method, an evolutionary-distance method, and
the evolutionary-parsimony method. The phylogenetic inferences generated by
maximum-parsimony and distance methods support both monophyly of the
Arthropoda and monophyly of the Chelicerata within the Arthropoda. These
results are congruent with phylogenies based on rigorous cladistic analyses
of morphological characters. Results support the inclusion of the
Arthropoda within a spiralian or protostome coelomate clade that is the
sister group of a deuterostome clade, refuting the hypothesis that the
arthropods represent the "primitive" sister group of a protostome coelomate
clade. Bootstrap analyses and consideration of all trees within 1% of the
length of the most parsimonious tree suggest that relationships between the
nonchelicerate arthropods and relationships within the chelicerate clade
cannot be reliably inferred with the partial 18S rRNA sequence data. With
the evolutionary-parsimony method, support for monophyly of the Arthropoda
is found in the majority of the combinations analyzed if the coelomates are
used as "outgroups." Monophyly of the Chelicerata is supported in most
combinations assessed. Our analyses also indicate that the
evolutionary-parsimony method, like distance and parsimony, may be biased
by taxa with long branches. We suggest that a previous study's inference of
the Arthropoda as paraphyletic may be the result of (a) having two few
arthropod taxa available for analysis and (b) including long-branched taxa.
相似文献
328.
Central processing of inertial sensory information about head attitude and motion in space is crucial for motor control. Vestibular signals are coded relative to a non-inertial system, the head, that is virtually continuously in motion. Evidence for transformation of vestibular signals from head-fixed sensory coordinates to gravity-centered coordinates have been provided by studies of the vestibulo-ocular reflex. The underlying central processing depends on otolith afferent information that needs to be resolved in terms of head translation related inertial forces and head attitude dependent pull of gravity. Theoretical solutions have been suggested, but experimental evidence is still scarce. It appears, along these lines, that gaze control systems are intimately linked to motor control of head attitude and posture. 相似文献
329.
330.
Several and various types of cells contain fine cytoplasmic filaments closely resembling the myofilaments of muscle cells (2, 18, 23, 24). In many of these cells and especially when cultured, it has been demonstrated that some of these filaments react with heavy meromyosin (HMM) in the same way as do the actin filaments of muscle cells (3, 6 7). This suggests that these filaments may be actinoid and form part of a contractile system. As fine intracytoplasmic filaments do occur in lymphatic endothelial cells (2, 14), we undertook an electron microscope investigation of their fine structure and their reaction on incubation with HMM and EDTA. We postulated that lymphatic endothelial cells possess a contractile filamentous system to which these filaments belong. 相似文献