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91.
92.
Thomas Ant Martha Koukidou Polychronis Rempoulakis Hong-Fei Gong Aris Economopoulos John Vontas Luke Alphey 《BMC biology》2012,10(1):1-8
Ubiquitin signaling pathways rely on E3 ligases for effecting the final transfer of ubiquitin from E2 ubiquitin conjugating enzymes to a protein target. Here we re-evaluate the hybrid RING/HECT mechanism used by the E3 family RING-between-RINGs (RBRs) to transfer ubiquitin to substrates. We place RBRs into the context of current knowledge of HECT and RING E3s. Although not as abundant as the other types of E3s (there are only slightly more than a dozen RBR E3s in the human genome), RBRs are conserved in all eukaryotes and play important roles in biology. Re-evaluation of RBR ligases as RING/HECT E3s provokes new questions and challenges the field. 相似文献
93.
94.
Aarón Salinas-Rodríguez Ma. Del Pilar Torres-Pereda Betty Manrique-Espinoza Karla Moreno-Tamayo Martha María Téllez-Rojo Solís 《PloS one》2014,9(11)
Background
In 2007, a non-contributory pension program was launched in rural areas of Mexico. The program consisted in a non-conditional cash transfer of US$40 monthly to all older adults (OA) aged 70 and over. We evaluate the effect of the program on mental well-being of its beneficiaries.Methods and Findings
Quantitative and qualitative methods were used. For the quantitative component, we used the selection criteria established by the program (age and locality size) to form the Intervention (OA aged 70–74 residing in rural localities, <2500 inhabitants) and Control groups (OA aged 70–74, in localities with 2501–2700 inhabitants). Baseline data collection was conducted in 2007 where 5,465 OA were interviewed. The follow-up survey was conducted in 2008, and it was possible to interview 5,270 OA, with a response rate of 96%. A difference-in-difference linear probability model with individual fixed effect was used to estimate the impact of the program on mental well-being indicators. In 2009 a qualitative component was designed to explore possible causal pathways of such effect.Results
After a year of exposure, the program had a significant effect on reduction of depressive symptoms (β = −0.06, CI95% −0.12; −0.01) and an increase in empowerment indicators: OA participated in important household decisions (β = 0.09, CI95% 0.03;0.15); and OA participated in household decisions pertaining to expenses (β = 0.11, CI95% 0.05;0.18). Qualitative analysis found a strong trend showing a reduction of sadness, and feeling of increasing empowerment.Conclusions
These results suggest that a non-conditional transfer in older ages have an impact beyond the economic sphere, impacting even the mental well-being. This effect could be explained because the pension produces feelings of safety and welfare. It is recommendable that governments should invest efforts towards universalizing the non-contributory pension programs in order to ensure a basic income for the elderly. 相似文献95.
Xiaoning Han Michael Chen Fushun Wang Martha Windrem Su Wang Steven Shanz Qiwu Xu Nancy Ann Oberheim Lane Bekar Sarah Betstadt Alcino J. Silva Takahiro Takano Steven A. Goldman Maiken Nedergaard 《Cell Stem Cell》2013,12(3):342-353
Download : Download video (32MB) 相似文献
96.
Chloé Cipolletta Noemi Spagnoletti Angelique Todd Martha M. Robbins Heather Cohen Sarah Pacyna 《International journal of primatology》2007,28(2):457-476
Though insectivory by large-bodied gorillas may be unexpected, researchers have reported it in all populations of gorillas
studied to date. Our study of 2 well monitored groups of western gorillas (Gorilla gorilla gorilla) at Bai Hokou in Dzanga-Ndoki National Park, Central African Republic provides information on frequency and variability of
termite consumption (the most commonly eaten insect) as well as some of the first direct observations of the behavior. Pooled
data from both groups indicate termite feeding on 34% and 83% of days, through fecal analysis and feeding trails, respectively.
Direct observations revealed that termite feeding occurred on 91% of the days for 1 group, in which the silverback fed on
termites during 13% of all feeding scans, making termites the most commonly observed food item. The group that had a higher
density of termite mounds in its home range consumed termites more frequently than the other group did. A higher proportion
of fecal samples from the silverbacks contained termite remains than the ones from adult females and juveniles. Termite consumption
was lower during the dry season, but it does not correlate with rainfall, measures of fruit availability, or fruit consumption.
Displacements at termite mounds occurred more than expected, indicating that they are a patchy, sought-after food resource.
Gorillas did not use tools to extract termites, but they used 2 different techniques to remove them from the cells. Though
culture or social traditions may cause the variation in termite consumption across sites, further investigation of termite
availability and consumption is necessary to rule out ecological and methodological explanations for observed variations. 相似文献
97.
Sen A Baxa U Simon MN Wall JS Sabate R Saupe SJ Steven AC 《The Journal of biological chemistry》2007,282(8):5545-5550
Fungal prions are infectious filamentous polymers of proteins that are soluble in uninfected cells. In its prion form, the HET-s protein of Podospora anserina participates in a fungal self/non-self recognition phenomenon called heterokaryon incompatibility. Like other prion proteins, HET-s has a so-called "prion domain" (its C-terminal region, HET-s-(218-289)) that is responsible for induction and propagation of the prion in vivo and for fibril formation in vitro. Prion fibrils are thought to have amyloid backbones of polymerized prion domains. A relatively detailed model has been proposed for prion domain fibrils of HET-s based on a variety of experimental constraints (Ritter, C., Maddelein, M. L., Siemer, A. B., Luhrs, T., Ernst, M., Meier, B. H., Saupe, S. J., and Riek, R. (2005) Nature 435, 844-848). To test specific predictions of this model, which envisages axial stacking of beta-solenoids with two coils per subunit, we examined fibrils by electron microscopy. Electron diffraction gave a prominent meridional reflection at (0.47 nm)(-1), indicative of cross-beta structure, as predicted. STEM (scanning transmission electron microscopy) mass-per-unit-length measurements yielded 1.02 +/- 0.16 subunits per 0.94 nm, in agreement with the model prediction (1 subunit per 0.94 nm). This is half the packing density of approximately 1 subunit per 0.47 nm previously obtained for fibrils of the yeast prion proteins, Ure2p and Sup35p, whence it follows that the respective amyloid architectures are basically different. 相似文献
98.
Twenty-four-hour variations in activity,core temperature,metabolic rate,and respiratory quotient in captive chinese pangolins 总被引:1,自引:0,他引:1
Martha E. Heath 《Zoo biology》1987,6(1):1-10
The circadian rhythms in activity, core temperature (Tc), O2 consumption, CO2 production, and respiratory quotient (RQ) were monitored in four captive Chinese pangolins (Manis pentadactyla). The pangolins were strictly nocturnal, never emerging from their nest before 1600 h, and their intermittent activity continued no later than 0230. As is usual in nocturnal mammals, the highest values observed in Tc, O2 consumption, and CO2 production occurred during the night; the lowest values occurred during the day. The magnitude of the variation in Tc, O2 consumption, CO2 production, and RQ averaged 1.2°C, 1.3 ml O2 kg?1 min?1, 1.2 ml CO2 kg?1 min?1, and 0.24, respectively. The circadian pattern in RQ was independent of activity, Tc, and the metabolic parameters and was of a different character than the patterns exhibited in the other variables. RQ remained constant at either a high or low level for long periods (8–10 h) and then increased or decreased relatively rapidly (1–2h) to the other level as in a square wave, whereas the rhythms in the other variables are similar to sine waves. The sharp increase in RQ was followed by a slow decline in Tc, and the sharp decline in RQ was followed by a slow increase in Tc. 相似文献
99.
Goldfish (Carassius auratus) and bluegill sunfish (Lepomis macrochirus) were placed in aquaria where their locomotor activity was monitored by photocells, and tested at various acclimation temperatures over a range encompassing their final thermal preferenda. Activity was pooled over 24-hour periods to eliminate any circadian rhythm effects. Both species exhibited an activity well of reduced locomotor activity in the region of the final preferendum. Goldfish, tested either singly or in groups of 2–5 individuals, exhibited a social-interaction effect which became more pronounced at higher temperatures. These results are discussed in relation to a thermokinetic interpretation of thermo-regulatory behavior in fishes, and to the correspondence between thermal preferenda and thermal optima. 相似文献
100.
Effects of boric acid supplementation on bone histomorphometry,metabolism, and biomechanical properties in aged female F-344 rats 总被引:1,自引:0,他引:1
Gallardo-Williams MT Maronpot RR Turner CH Johnson CS Harris MW Jayo MJ Chapin RE 《Biological trace element research》2003,93(1-3):155-169
Postmenopausal women may benefit from dietary interventions in order to increase bone strength and prevent fractures. Dietary
boron (B) may be beneficial for optimal calcium metabolism and, as a consequence, optimal bone metabolism. The present study
evaluated the effects of boron, in the form of boric acid, with or without 17β-estradiol (E2) supplementation (via subcutaneous implant), in ovariectomized (OVX) aged 13-mo-old F-344 rats. Boric acid was administered
by gavage at a subtoxic dose (8.7 mg B/kg/d) for 40 d. Results indicate that serum level of minerals as well as osteocalcin
(a marker of bone resorption) are dependent to a greater extent on the hormonal status of the animals than on boron supplementation.
Boron treatment increased the E2-induced elevation of urinary calcium and magnesium. Bone mineral density (BMD) of the L5 vertebra and proximal femur was
highest in the E2-treated groups; no increase in BMD was conferred by boron treatment. By histomorphometry of the proximal tibial metaphysis,
osteoblastic, osteoid, and eroded surfaces were significantly suppressed by E2 treatment, but not by boron treatment. In biomechanical testing of femur and vertebra, neither E2 nor boron treatment significantly increased bone strength. At the levels given, boron alone provided no protection against
OVX-induced osteopenia. In addition, combination therapy (B + E2) provided no additional benefits over those of 17β-estradiol treatment alone in this aged rat model. 相似文献