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91.
Amol A. Verma Tejasvi Hora Hae Young Jung Michael Fralick Sarah L. Malecki Lauren Lapointe-Shaw Adina Weinerman Terence Tang Janice L. Kwan Jessica J. Liu Shail Rawal Timothy C.Y. Chan Angela M. Cheung Laura C. Rosella Marzyeh Ghassemi Margaret Herridge Muhammad Mamdani Fahad Razak 《CMAJ》2021,193(23):E859
92.
Han Dai Lauren Kustigian David Carney April Case Thomas Considine Basil P. Hubbard Robert B. Perni Thomas V. Riera Bruce Szczepankiewicz George P. Vlasuk Ross L. Stein 《The Journal of biological chemistry》2010,285(43):32695-32703
SIRT1 is a protein deacetylase that has emerged as a therapeutic target for the development of activators to treat diseases of aging. SIRT1-activating compounds (STACs) have been developed that produce biological effects consistent with direct SIRT1 activation. At the molecular level, the mechanism by which STACs activate SIRT1 remains elusive. In the studies reported herein, the mechanism of SIRT1 activation is examined using representative compounds chosen from a collection of STACs. These studies reveal that activation of SIRT1 by STACs is strongly dependent on structural features of the peptide substrate. Significantly, and in contrast to studies reporting that peptides must bear a fluorophore for their deacetylation to be accelerated, we find that some STACs can accelerate the SIRT1-catalyzed deacetylation of specific unlabeled peptides composed only of natural amino acids. These results, together with others of this study, are at odds with a recent claim that complex formation between STACs and fluorophore-labeled peptides plays a role in the activation of SIRT1 (Pacholec, M., Chrunyk, B., Cunningham, D., Flynn, D., Griffith, D., Griffor, M., Loulakis, P., Pabst, B., Qiu, X., Stockman, B., Thanabal, V., Varghese, A., Ward, J., Withka, J., and Ahn, K. (2010) J. Biol. Chem. 285, 8340–8351). Rather, the data suggest that STACs interact directly with SIRT1 and activate SIRT1-catalyzed deacetylation through an allosteric mechanism. 相似文献
93.
A novel tubular bioassay system has been developed that allows both concentration profiles and the local production and concentration of antagonistic chemicals at the fungal/pathogen interface to be measured analytically. 相似文献
94.
The Population Study of Women in Gothenburg, Sweden is an ongoing prospective study of female residents who were recruited from the local registry in 1968–1969 when they were 38–60 years old. The data presented here were collected from 361 healthy women who underwent a baseline physical examination including a supplementary dietary history interview and returned for a second general health examination 6 years later. This report identifies a subgroup of 57 women who were sedentary during their leisure time and appear to have been particularly susceptible to gaining weight as a function of the fat content of their diets. Specifically, longitudinal analysis of body weights in the whole sample revealed a statistical interaction between leisure-time physical activity and habitual dietary fat intake (energy-%), as reported at the baseline examination, in the prediction of subsequent weight change. Further stratified analysis suggested that weight changes were significantly dependent on dietary fat intake among the sedentary women only. High energy intake also predicted weight gain in the sedentary group, although the predictive value for a high-fat diet was of marginal significance after adjusting for total energy consumption. These results suggest that sedentary recreational activity plus a low-fat diet may have a combined contribution to weight change that is not equivalent to the sum of the separate effects. Such a synergy between two modifiable lifestyle factors seems highly relevant for prevention of obesity. 相似文献
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96.
The abundance and distribution of an invasive species is influenced by its relative ability to find resources under a variety of conditions. We examined the exploitative ability of the Argentine ant (Linepithema humile (Mayr)), in comparison with two common New Zealand ant species Monomorium antarcticum (Fr. Smith) and Prolasius advenus (Hymenoptera: Formicidae) (Fr. Smith), using maze trials under different temperature and starvation regimes. Our results showed temperature significantly affected the mean time to discover food resources, but different species responded differently to changes in temperature. A change in temperature from 23°C to 13°C resulted in an approximately 8‐fold increase in the time to discover food for native P. advenus, but discovery times remained relatively similar for invasive Argentine ants. Starvation did not significantly influence the ability of species to find food. Argentine ants consistently located and recruited to food faster than the native species. We examined for variation in walking speed under the experimental conditions as a mechanism for our results. The results revealed Argentine ants and P. advenus to have similar walking speeds at each temperature‐starvation treatment and both were faster than M. antarcticum. However, Argentine ants had rates of turning or returning to the nest that were lower than the native species. This result suggests that Argentine ants show greater ‘exploratory willingness’ or ‘novelty seeking’ behaviour. Our results suggest that Argentine ants are able to discovery and exploit resources more efficiently than these native species under a wide spectrum of environmental and physiological conditions. Such relative efficiencies have likely contributed to the success of this invader. 相似文献
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There is growing support for the general notion that the drivers of invasion success often shift from biotic to abiotic factors
with increasing spatial scale. Most of this research, however, has been conducted on a single trophic level; i.e. it has primarily
looked at how the diversity of native competitors may influence invasion success. Less attention has been paid to understanding
how native prey diversity may influence the invasion success of exotic predators and whether such biotic factors are scale-dependent.
We used a hierarchical spatial survey of 17 stream communities to test whether native prey diversity, along with native prey
biomass, algal resource abundance and annual stream discharge, influenced the abundance of an exotic crayfish predator, and
whether the importance of these factors were scale-dependent. We used a hierarchical generalized linear model to evaluate
the influence of these community and stream characteristics on exotic crayfish abundance at both the transect scale (1 m2) and the stream scale (400 m2). Our results indicated that at the stream scale, high stream discharge significantly limited invader abundance. However,
at the smaller transect scale, native prey biomass was a significant driver of invasion success and positively correlated
with invader abundance. We suggest that our results add to the emerging pattern that abiotic processes are stronger determinants
of invasion success at large spatial scales, whereas biotic processes become more important with decreasing spatial scale.
However, for predator invasions, prey biomass, not prey diversity may be a more important for driver of invasion success at
small spatial scales. 相似文献
100.
Sarah J. Alger Cynthia A. Kelm‐Nelson Sharon A. Stevenson Charity Juang Stephen C. Gammie Lauren V. Riters 《Genes, Brain & Behavior》2020,19(2)
Dopaminergic projections from the ventral tegmental area (VTA) to multiple efferent targets are implicated in pair bonding, yet the role of the VTA in the maintenance of long‐term pair bonds is not well characterized. Complex interactions between numerous neuromodulators modify activity in the VTA, suggesting that individual differences in patterns of gene expression in this region may explain individual differences in long‐term social interactions in bonded pairs. To test this hypothesis we used RNA‐seq to measure expression of over 8000 annotated genes in male zebra finches in established male‐female pairs. Weighted gene co‐expression network analysis identified a gene module that contained numerous dopamine‐related genes with TH found to be the most connected gene of the module. Genes in this module related to male agonistic behaviors as well as bonding‐related behaviors produced by female partners. Unsupervised learning approaches identified two groups of males that differed with respect to expression of numerous genes. Enrichment analyses showed that many dopamine‐related genes and modulators differed between these groups, including dopamine receptors, synthetic and degradative enzymes, the avian dopamine transporter and several GABA‐ and glutamate‐related genes. Many of the bonding‐related behaviors closely associated with VTA gene expression in the two male groups were produced by the male's partner, rather than the male himself. Collectively, results highlight numerous candidate genes in the VTA that can be explored in future studies and raise the possibility that the molecular/genetic organization of the VTA may be strongly shaped by a social partner and/or the strength of the pair bond. 相似文献