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291.
With the pandemic of type 2 diabetes (T2D), there is an ever-increasing need to fully understand the underlying mechanisms of the disease. Type 2 diabetes shows a high heritability risk (25–80%); however, genes account only for 10% of this risk. From all the risk factors for diabetes, epigenetic mechanisms have the highest statistical scoring in explaining the disease. A multitude of organ-specific epigenomic changes have been linked to type 2 diabetes. Nutritional influences, mainly in the early life, physical activity level, environmental toxins act as epigenetic factors and the recognized epigenetic changes can represent a therapeutical target, new drugs being currently in development for this application. Our current review focuses on the most common epigenetic modifications linked to type 2 diabetes or insulin resistance, the potentially emerging epigenetic-related interventions and pharmacoepigenetic knowledge. 相似文献
292.
Prevalence of streptomycin-resistance genes in bacterial populations in European habitats 总被引:2,自引:0,他引:2
293.
Theodora Fuss Horst Bleckmann Vera Schluessel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2014,200(1):19-35
This study assessed spatial memory and orientation strategies in Chiloscyllium griseum. In the presence of visual landmarks, six sharks were trained in a fixed turn response. Group 1 started from two possible compartments approaching two goal locations, while group 2 started from and approached only one location, respectively. The learning criterion was reached within 9 ± 5.29 (group 1) and 8.3 ± 3.51 sessions (group 2). Transfer tests revealed that sharks had applied a direction strategy, possibly in combination with some form of place learning. Without visual cues, sharks relied solely on the former. To identify the underlying neural substrate(s), telencephalic were lesioned and performance compared before and after surgery. Ablation of the dorsal and medial pallia only had an effect on one shark (group 1), indicating that the acquisition and retention of previously gained knowledge were unaffected in the remaining four individuals. Nonetheless, the shark re-learned the task. In summary, C. griseum can utilize fixed turn responses to navigate to a goal; there is also some evidence for the use of external visual landmarks while orienting. Probably, strategies can be used alone or in combination. Neither the dorsal nor medial pallium seems to be responsible for the acquisition and processing of egocentric information. 相似文献
294.
Information on the metal biological fate in macrophyte-based coastal lagoons is provided; this information can contribute
to the assessment of the environmental effects of metal pollution and to the development of predictive models for rational
management of coastal lagoons. Iron, Zn, Cu, Pb and Cd concentrations in the dominant invertebrate and fish species of Monolimni
Lagoon, Mediterranean Sea, as well as in potential major sources for metal accumulation in these animals (water, sediments,
angiosperms, seaweeds), were measured. Principal Component Analysis (PCA) was conducted using metal concentrations in invertebrates
and fishes. All five metal concentrations loaded significantly on the first PCA axis; however, Zn and Cu loadings were less
significant than Cd and even less than Fe and Pb ones. The samples of deposit-feeding invertebrates were separated from those
of the rest of the organisms (browsing, herbivorous and carnivorous invertebrates, carnivorous gobies and muscle tissues of
detritivorous mullets) along the first PCA axis. Deposit-feeding invertebrates displayed the highest Fe and Pb contents, and
in general, the highest or comparatively high Cd, Zn and Cu ones. Carnivorous gobies showed comparatively high Zn contents
and carnivorous shrimps the highest Cu ones, while muscle tissues of detritivorous mullets had low metal loads. In addition,
there was no essential increase in metal concentrations corresponding to the increasing trophic level (autotrophs, to herbivores,
to carnivores). Our findings suggest that (a) the variability in Fe, Pb and Cd contents in invertebrates and gobies depends
at least to some extent on interspecific differences in feeding habits—deposit feeders accumulated the highest metal amounts
probably due to high rates of uptake from sediments, (b) the variability in Zn and Cu concentrations in these organisms depends
also on other interspecific differences apart from those in feeding habits, (c) metal accumulation in mullet muscle tissues
does not depend markedly on feeding habits and (d) the trophic transfer of macrophyte-bound metals to the coastal lagoon food
web is of relatively minor importance. 相似文献
295.
Maria Lazarina Stefanos P. Sgardelis Thomas Tscheulin Jelle Devalez Vangelis Mizerakis Athanasios S. Kallimanis Spyridon Papakonstantinou Thanassis Kyriazis Theodora Petanidou 《Biodiversity and Conservation》2017,26(1):115-131
Fire affects diversity and structure of flower-visitor communities. We explored the effect of fire history on the diversity patterns and structure of the flower-visitor guilds (bees, beetles, flies, sawflies, and wasps), across a post-fire regeneration sequence of pine forests in Rhodes Island, Greece. Fire history was defined by fire frequency and post-fire age of sites. We did not find significant differences in species richness and abundance per guild between fire-history regimes except for the abundance of flies, sawflies and the entire flower-visitor community. Fire strongly affected the community structure of bees, beetles, and sawflies. Some of the most abundant and common species responded significantly to fire in terms of abundance; yet, we observed no significant variation in the abundance of the common species of bees, the most prominent pollinator group, implying that provision of pollination services may not be considerably affected by fire. Long-unburnt sites displayed higher heterogeneity in species composition compared to recently-burnt sites (either burnt once or twice). This pattern deviated significantly from null expectations when analyzing the abundance-based metric of β-diversity and was obscure in the case of the presence/absence-based metric, indicating that fire affected mainly the spatial distribution of individuals, i.e. the main change is not due to species turnover but to changes in relative abundance. Furthermore, the species composition in recently-burnt sites (burnt once in 2008) were more similar than in twice-burnt sites (including areas burnt once between 1984 and 1992, and in 2008), indicating that fire frequency affected post-fire heterogeneity of species composition. 相似文献
296.
297.
Maria V. Triantaphyllou Theodora Tsourou Olga Koukousioura Michael D. Dermitzakis 《Revue de Micropaléontologie》2005,48(4):279-302
A comparative study of recent epiphytal ostracod and benthic foraminiferal populations was conducted in August 2001, at two gulfs (Korthi and Kastro) located at the southeastern part of Andros Island (middle Aegean Sea, Greece). Thirty samples (representing living macro-benthic algae and seagrasses) from both gulfs were studied and a total of 34 ostracod species and 60 benthic foraminiferal species were identified. In the gulf of Korthi both benthic foraminiferal and epiphytal ostracod assemblages were characterized by high abundances of Amphistegina lessonii and Xestoleberis spp., respectively, therefore the performed Q-mode cluster analysis verified the presence of a Normal Environment Biofacies (NE). Declined Environment (DE) and Stressed (SE) Environment Biofacies were recognized in the gulf of Kastro, an area more affected by anthropogenic activities. Several deformed foraminiferal specimens have been documented in the assemblages from both gulfs, but malformed tests are significantly increased in SE Biofacies of Kastro gulf. This study suggests that great accumulations of A. lessonii (35-60%) associated with high frequencies of Xestoleberis communis and/or Xestoleberis decipiens and high species diversities can be used as bioindicators of coastal health. 相似文献
298.
Aphrodite Kantsa Jair E. Garcia Robert A. Raguso Adrian G. Dyer Ronny Steen Thomas Tscheulin Theodora Petanidou 《American journal of botany》2023,110(1):e16098
Premise
Capparis spinosa is a widespread charismatic plant, in which the nocturnal floral habit contrasts with the high visitation by diurnal bees and the pronounced scarcity of hawkmoths. To resolve this discrepancy and elucidate floral evolution of C. spinosa, we analyzed the intrafloral patterns of visual and olfactory cues in relation to the known sensory biases of the different visitor guilds (bees, butterflies, and hawkmoths).Methods
We measured the intrafloral variation of scent, reflectance spectra, and colorimetric properties according to three guilds of known visitors of C. spinosa. Additionally, we sampled visitation rates using a motion-activated camera.Results
Carpenter bees visited the flowers eight times more frequently than nocturnal hawkmoths, at dusk and in the following morning. Yet, the floral headspace of C. spinosa contained a typical sphingophilous scent with high emission rates of certain monoterpenes and amino-acid derived compounds. Visual cues included a special case of multisensory nectar guide and color patterns conspicuous to the visual systems of both hawkmoths and bees.Conclusions
The intrafloral patterns of sensory stimuli suggest that hawkmoths have exerted strong historical selection on C. spinosa. Our study revealed two interesting paradoxes: (a) the flowers phenotypically biased towards the more inconsistent pollinator; and (b) floral display demands an abundance of resources that seems maladaptive in the habitats of C. spinosa. The transition to a binary pollination system accommodating large bees has not required phenotypic changes, owing to specific eco-physiological adaptations, unrelated to pollination, which make this plant an unusual case in pollination ecology. 相似文献299.