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121.
Melanie Rae Simpson Gaute Brede Jostein Johansen Roar Johnsen Ola Storr? P?l S?trom Torbj?rn ?ien 《PloS one》2015,10(12)
Background
Perinatal probiotic ingestion has been shown to prevent atopic dermatitis (AD) in infancy in a number of randomised trials. The Probiotics in the Prevention of Allergy among Children in Trondheim (ProPACT) trial involved a probiotic supplementation regime given solely to mothers in the perinatal period and demonstrated a ~40% relative risk reduction in the cumulative incidence of AD at 2 years of age. However, the mechanisms behind this effect are incompletely understood. Micro-RNAs (miRNA) are abundant in mammalian milk and may influence the developing gastrointestinal and immune systems of newborn infants. The objectives of this study were to describe the miRNA profile of human breast milk, and to investigate breast milk miRNAs as possible mediators of the observed preventative effect of probiotics.Methods
Small RNA sequencing was conducted on samples collected 3 months postpartum from 54 women participating in the ProPACT trial. Differential expression of miRNA was assessed for the probiotic vs placebo and AD vs non-AD groups. The results were further analysed using functional prediction techniques.Results
Human breast milk samples contain a relatively stable core group of highly expressed miRNAs, including miR-148a-3p, miR-22-3p, miR-30d-5p, let-7b-5p and miR-200a-3p. Functional analysis of these miRNAs revealed enrichment in a broad range of biological processes and molecular functions. Although several miRNAs were found to be differentially expressed on comparison of the probiotic vs placebo and AD vs non-AD groups, none had an acceptable false discovery rate and their biological significance in the development of AD is not immediately apparent from their predicted functional consequences.Conclusion
Whilst breast milk miRNAs have the potential to be active in a diverse range of tissues and biological process, individual miRNAs in breast milk 3 months postpartum are unlikely to play a major role in the prevention of atopic dermatitis in infancy by probiotics ingestion in the perinatal period.Trial Registration
ClinicalTrials.gov NCT00159523相似文献122.
Background
Speciation often occurs in complex or uncertain temporal and spatial contexts. Processes such as reinforcement, allopatric divergence, and assortative mating can proceed at different rates and with different strengths as populations diverge. The Central American Midas cichlid fish species complex is an important case study for understanding the processes of speciation. Previous analyses have demonstrated that allopatric processes led to species formation among the lakes of Nicaragua as well as sympatric speciation that is occurring within at least one crater lake. However, since speciation is an ongoing process and sampling genetic diversity of such lineages can be biased by collection scheme or random factors, it is important to evaluate the robustness of conclusions drawn on individual time samples. 相似文献123.
The purpose of this study was to systematically investigate how high doses of sparsely and densely ionizing radiations influence
the proliferation time of lymphocytes in short-term cultures and, consequently, the observed frequencies of dicentric and
centric ring chromosomes. Peripheral blood samples from five volunteers were irradiated with high doses of 200 kV X-rays and
with neutrons with a mean energy of <E
n>=2.1 MeV. First division metaphase cells were collected after different culture times of 48, 56, and 72 h and dicentrics,
centric ring chromosomes, and acentric fragments were determined. The data hint at considerable mitotic delay. The main increase
in the number of chromosome aberrations occurred between 48 and 72 h after an X-ray exposure and between 56 and 72 h after
neutron exposure. When the data were used for a calibration of aberration frequency versus dose, subsequent dose estimations
resulted, however, in comparable values. Thus, in spite of the influence of mitotic delay on observable chromosome aberrations,
at least for the radiation types investigated here, a culture time of 48 h is acceptable for biological dosimetry. 相似文献
124.
Contrasting population structures in two sympatric anurans: implications for species conservation 总被引:4,自引:0,他引:4
A general prediction of the neutral theory of evolution is that genetic diversity should correlate positively with effective population size. We show here that diversity across eight microsatellite loci was consistently and substantially lower in one common amphibian (Bufo bufo) than in another with similar life history traits (Rana temporaria) despite B. bufo having the larger breeding assemblage sizes. However, B. bufo breeding assemblages were much more highly differentiated than those of R. temporaria according to both Fst and Rst estimators. These differences occurred in shared habitats across identical geographical distances. The patterns of genetic diversity and differentiation detected in these two species were probably a consequence of high gene flow in R. temporaria but much lower gene flow among the larger but more dispersed B. bufo assemblages. These observations highlight the difficulty of defining the boundaries of wild populations, and show how two broadly similar species can exhibit very different population dynamics. 相似文献
125.
Attention and the detectability of weak taste stimuli 总被引:2,自引:1,他引:1
Subjects detected weak solutions of sucrose or citric acid under conditions
in which attention was directed toward one of the tastants or the other.
Detection thresholds were measured using an adaptive, forced-choice
procedure, with a three-down one-up rule, which computer simulations
suggest should be more reliable than the popular two-down one-up rule. The
thresholds were modestly but systematically lower for attended tastants
than for unattended ones. Similar results have been reported in other sense
modalities, including vision (greater sensitivity to stimuli presented to
attended versus unattended spatial locations) and hearing (greater
sensitivity to stimuli presented at attended versus unattended sound
frequencies). Taken together, the findings are consistent with a general
hypothesis regarding attention in sensory systems: gains or losses in
detectability occur when a central attentional mechanism (or, conceivably,
a preattentive mechanism) selectively and preferentially monitors signals
arising from particular subsets of peripheral neural inputs.
相似文献
126.
127.
Our experiment involved seven panels and six chocolates – five dark chocolates and one milk chocolate. The aim of the study was to compare the sensory profiles of the chocolates. A natural question to ask is “Did the panelists detect any differences among the five dark chocolates or did they systematically contrast them with the milk chocolate?” The scatter plot of the chocolates obtained by principal component analysis was useless to answer that question, because of the proximity of the points. To overcome that, we used confidence ellipses calculated using bootstrap. The originality of the study lies in the fact that we applied those ellipses to hierarchical multiple factor analysis (HMFA): among the seven panels, six were composed of trained professionals and the last one was composed of untrained students, and through that method, we managed to compare the two types of panels and balance the role of each trained panel. HMFA provides in a single scatter plot a representation of the six chocolates for each panel, the trained panels and all the panels. Confidence ellipses around each chocolate show that the combined panels – the six trained panels and also the untrained panel – differentiate the five dark chocolates. They also show how much larger the untrained panel's variability is than that of the trained panels, and how comparable are the trained panels' variability to each other. 相似文献
128.
Das internationale “Consortium for the Barcode of Life” will ein standardisiertes DNA‐Fragment aller Organismenarten der Welt sequenzieren. Dieser “Barcode” soll dazu dienen, Arten schnell und eindeutig zu bestimmen. Ziel ist neben der Katalogisierung des Lebens auf unserem Planeten auch die Entwicklung eines handlichen Geräts, das in der Lage ist, kostengünstig kleine Proben eines Organismus einer Art zuzuordnen. Profitieren können von diesem Ansatz nicht nur die Grundlagenforschung, sondern auch gesellschaftliche und politische Institutionen. Zudem stellt DNA‐Barcoding einen sehr wichtigen Beitrag zur Beschreibung der Artenvielfalt dar, da es diesen Prozess stark beschleunigen kann. 相似文献
129.
130.
JÉRÔME MUNZINGER 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(1):91-97
While working on a treatment of Violaceae for the Flore de Nouvelle-Caledonie et dependences , two new species were recognized, Agatea veillonii Munzinger and A. lecointei Munzinger. These species are here described and illustrated. Some taxonomic notes and a regional identification key are provided. 相似文献