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991.
Becky E. Raboy Gustavo R. Canale James M. Dietz 《International journal of primatology》2008,29(2):449-467
We provide data on wild Callithrix kuhlii, a little studied species. We describe their ecology, focusing on demography, diet, and ranging patterns in 8 groups studied
from 1995 to 1999. The groups averaged 4.3 individuals, with 1 breeding female and 1–2 adult males, and reproduction was seasonal.
Evidence from nonstudy groups indicated the possibility of polygynous group structure. We observed group formation and the
transfer of adults between groups. The marmosets ate 20 species of fruit and nectar and 5 exudate species. Home ranges were
34–39 ha, and daily path lengths averaged 1498 m. We include our data in a comprehensive review of eastern Brazilian marmosets
to characterize their ecology. Callithrix kuhlii ate more fruit species and less gum species, and had larger home ranges and daily path lengths versus those of most congeners.
There was also a tradeoff between travel time and other behaviors. Species with smaller home ranges spent more time foraging
and resting and less time traveling than the ones with larger ranges. Attributes consistent with all species included their
reliance on gum during fruit scarcity and preference for disturbed habitat. We explored factors relating to the variation
in diet and ranging patterns within the eastern Brazilian marmosets, in particular by considering the species in relation
to elevation and the extent and proximity of their distribution to the sea. However, large intraspecific variation resulting
in part from variable levels of anthropogenic disturbance across sites confounded our ability to verify trends corresponding
to the geographic characteristics. 相似文献
992.
Background
The Mitotic Spindle Assembly Checkpoint (MSAC) is an evolutionary conserved mechanism that ensures the correct segregation of chromosomes by restraining cell cycle progression from entering anaphase until all chromosomes have made proper bipolar attachments to the mitotic spindle. Its malfunction can lead to cancer.Principle Findings
We have constructed and validated for the human MSAC mechanism an in silico dynamical model, integrating 11 proteins and complexes. The model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. Originating from the biochemical reactions for the underlying molecular processes, non-linear ordinary differential equations for the concentrations of 11 proteins and complexes of the MSAC are derived. Most of the kinetic constants are taken from literature, the remaining four unknown parameters are derived by an evolutionary optimization procedure for an objective function describing the dynamics of the APC:Cdc20 complex. MCC:APC dissociation is described by two alternatives, namely the “Dissociation” and the “Convey” model variants. The attachment of the kinetochore to microtubuli is simulated by a switching parameter silencing those reactions which are stopped by the attachment. For both, the Dissociation and the Convey variants, we compare two different scenarios concerning the microtubule attachment dependent control of the dissociation reaction. Our model is validated by simulation of ten perturbation experiments.Conclusion
Only in the controlled case, our models show MSAC behaviour at meta- to anaphase transition in agreement with experimental observations. Our simulations revealed that for MSAC activation, Cdc20 is not fully sequestered; instead APC is inhibited by MCC binding. 相似文献993.
Recently, using the medial forebrain bundle (MFB) 6-hydroxydopmaine (6-OHDA) lesion rat model of Parkinson's disease (PD), we have demonstrated that blockade of central IGF-1 receptors (IGF-1R) attenuated estrogen neuroprotection of substantia nigra pars compacta (SNpc) DA neurons, but exacerbated 6-OHDA lesions in IGF-1 only treated rats (Quesada and Micevych [2004]: J Neurosci Res 75:107-116). This suggested that the IGF-1 system is a central mechanism through which estrogen acts to protect the nigrostriatal DA system. Moreover, these results also suggest that IGF-1R-induced intracellular signaling pathways are involved in the estrogen mechanism that promotes neuronal survival. In vitro, two convergent intracellular signaling pathways used by estrogen and IGF-1, the mitogen-activated protein kinase (MAPK/ERK), and phosphatidyl-inositol-3-kinase/Akt (PI3K/Akt), have been demonstrated to be neuroprotective. Continuous central infusions of MAPK/ERK and PI3K/Akt inhibitors were used to test the hypothesis that one or both of these signal transduction pathways mediates estrogen and/or IGF-1 neuroprotection of SNpc DA neurons after a unilateral administration of 6-OHDA into the MFB of rats. Motor behavior tests and tyrosine hydroxylase immunoreactivity revealed that the inhibitor of the PI3K/Akt pathway (LY294002) blocked the survival effects of both estrogen and IGF-1, while an inhibitor of the MAPK/ERK signaling (PD98059) was ineffective. Western blot analyses showed that estrogen and IGF-1 treatments increased PI3K/Akt activation in the SN; however, MAPK/ERK activation was decreased in the SN. Indeed, continuous infusions of inhibitors blocked phosphorylation of PI3K/Akt and MAPK/ERK. These findings indicate that estrogen and IGF-1-mediated SNpc DA neuronal protection is dependent on PI3K/Akt signaling, but not on the MAPK/ERK pathway. 相似文献
994.
995.
Release from prey preservation behavior via prey switch allowed diversification of cuticular hydrocarbon profiles in digger wasps
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Mareike Wurdack Carlo Polidori Alexander Keller Heike Feldhaar Thomas Schmitt 《Evolution; international journal of organic evolution》2017,71(11):2562-2571
The cuticle of insects is covered by a layer of hydrocarbons (CHC), whose original function is the protection from desiccation and pathogens. However, in most insects CHC profiles are species specific. While this variability among species was largely linked to communication and recognition functions, additional selective forces may shape insect CHC profiles. Here, we show that in Philanthinae digger wasps (Crabronidae) the CHC profile coevolved with a peculiar brood‐care strategy. In particular, we found that the behavior to embalm prey stored in the nest with hydrocarbons is adaptive to protect larval food from fungi in those species hunting for Hymenoptera. The prey embalming secretion is identical in composition to the alkene‐dominated CHC profile in these species, suggesting that their profile is adaptively conserved for this purpose. In contrast, prey embalming is not required in those species that switched to Coleoptera as prey. Released from this chemical brood‐care strategy, Coleoptera‐hunting species considerably diversified their CHC profiles. Differential needs to successfully protect prey types used as larval food have thus driven the diversification of CHCs profiles of female Philanthinae wasps. To the best of our knowledge, this is the first evidence of a direct link between selection pressure for food preservation and CHC diversity. 相似文献
996.
Vijay Tejwani Franz-Josef Schmitt Svea Wilkening Ingo Zebger Marius Horch Oliver Lenz Thomas Friedrich 《BBA》2017,1858(1):86-94
Ralstonia eutropha is a hydrogen-oxidizing (“Knallgas”) bacterium that can easily switch between heterotrophic and autotrophic metabolism to thrive in aerobic and anaerobic environments. Its versatile metabolism makes R. eutropha an attractive host for biotechnological applications, including H2-driven production of biodegradable polymers and hydrocarbons. H2 oxidation by R. eutropha takes place in the presence of O2 and is mediated by four hydrogenases, which represent ideal model systems for both biohydrogen production and H2 utilization. The so-called soluble hydrogenase (SH) couples reversibly H2 oxidation with the reduction of NAD+ to NADH and has already been applied successfully in vitro and in vivo for cofactor regeneration. Thus, the interaction of the SH with the cellular NADH/NAD+ pool is of major interest. In this work, we applied the fluorescent biosensor Peredox to measure the [NADH]:[NAD+] ratio in R. eutropha cells under different metabolic conditions. The results suggest that the sensor operates close to saturation level, indicating a rather high [NADH]:[NAD+] ratio in aerobically grown R. eutropha cells. Furthermore, we demonstrate that multicomponent analysis of spectrally-resolved fluorescence lifetime data of the Peredox sensor response to different [NADH]:[NAD+] ratios represents a novel and sensitive tool to determine the redox state of cells. 相似文献
997.
998.
Wilkening Svea Schmitt Franz-Josef Horch Marius Zebger Ingo Lenz Oliver Friedrich Thomas 《Photosynthesis research》2017,133(1-3):305-315
Photosynthesis Research - The fluorescent biosensor Frex, recently introduced as a sensitive tool to quantify the NADH concentration in living cells, was characterized by time-integrated and... 相似文献
999.
Roberto Carlos Agís‐Balboa Cemil Kerimoglu Eva Benito Michael Gertig Sanaz Bahari‐Javan Gaurav Jain Susanne Burkhardt Ivana Delalle Alexander Jatzko Markus Dettenhofer Patricia A Zunszain Andrea Schmitt Peter Falkai Julius C Pape Elisabeth B Binder Christophe Mulle Andre Fischer Farahnaz Sananbenesi 《The EMBO journal》2017,36(19):2815-2828
1000.
Vladimir D. Kreslavski Anatoly A. Kosobryukhov Franz-Josef Schmitt Galina A. Semenova Galina N. Shirshikova Aleksandra Yu Khudyakova Suleyman I. Allakhverdiev 《Protoplasma》2017,254(3):1283-1293
The reduced content of photoreceptors, such as phytochromes, can decrease the efficiency of photosynthesis and activity of the photosystem II (PSII). For the confirmation of this hypothesis, the effect of deficiency in both phytochromes (Phy) A and B (double mutant, DM) in 7–27-day-old Arabidopsis thaliana plants on the photosynthetic activity was studied in absence and presence of UV-A radiation as a stress factor. The DM with reduced content of apoproteins of PhyA and PhyB and wild type (WT) plants with were grown in white and red light (WL and RL, respectively) of high (130 μmol quanta m?2 s?1) and low (40 μmol quanta m?2 s?1) intensity. For DM and WT grown in WL, no notable difference in the photochemical activity of PSII was observed. However, the resistance of the photosynthetic apparatus (PA) to UV-A and the rate of photosynthesis under light saturation were lower in the DM compared to those in the WT. Growth in RL, when the photoreceptors of blue light—cryptochromes—are inactive, resulted in the significant decrease of the photochemical activity of PSII in DM compared to that in WT including amounts of QB-non-reducing complexes of PSII and noticeable enhancement of thermal dissipation of absorbed light energy. In addition, marked distortion of the thylakoid membrane structure was observed for DM grown in RL. It is suggested that not only PhyA and PhyB but also cryptochromes are necessary for normal functioning of the PA and formation of the mechanisms of its resistance to UV-radiation. 相似文献