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101.
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
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102.
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
103.
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
104.
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
105.
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
106.
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
107.
108.
High‐fat diet exacerbates pain‐like behaviors and periarticular bone loss in mice with CFA‐induced knee arthritis 下载免费PDF全文
Aleyda A. Loredo‐Pérez Carlos E. Montalvo‐Blanco Luis I. Hernández‐González Maricruz Anaya‐Reyes Cecilia Fernández del Valle‐Laisequilla Juan G. Reyes‐García Rosa I. Acosta‐González Arisai Martínez‐Martínez Jaira C. Villarreal‐Salcido Virginia M. Vargas‐Muñoz Enriqueta Muñoz‐Islas Martha B. Ramírez‐Rosas Juan M. Jiménez‐Andrade 《Obesity (Silver Spring, Md.)》2016,24(5):1106-1115
109.
Yike I Miller MJ Sorenson WG Walenga R Tomashefski JF Dearborn DG 《Mycopathologia》2002,154(3):139-152
In recent years cases of often fatal pulmonary hemorrhage in infants have been associated with water damaged homes and the
toxigenic fungusStachybotrys chartarum. The fungal spores contain mycotoxins which could be injurious to the rapidly developing lung. In order to understand the
developmental pathophysiology of this disease we developed an infant rat model of stachybotrytoxicosis describing the effects
of fungal spores on survival, growth, histopathology of the lung and respiration. Conidia ofS. chartarum were instilled intratracheally (1.0–8.0 × 105/gm wt.) in 4-dold Sprague-Dawley rat pups. Two control groups received either sterile PBS or a suspension of spores extensively
extracted with ethanol to remove toxins. Lethal dose response was determined (LD50 = 2.7 × 105 spores/gm wt.). All dead pups had extensively hemorrhagic lungs. Growth of surviving animals was impaired in a dose-dependent
manner. Changes of pulmonary function parameters in rats treated with 1.1 × 105 spores/g were consistent with an increased respiratory resistance. Histology of lungs revealed fresh hemorrhage, sparse hemosiderin-laden
macrophages, and evidence of inflammation including thickened alveolar septa infiltrated by lymphocytes and mononuclear cells
and intra-alveolar macrophages. Significant increases (p = 0.001) in numbers of macrophages (2-fold), lymphocytes (5-fold)
and neutrophils (7-fold) were found in BAL fluid. Hemoglobin was elevated 2-fold (p = 0.004). Proinflammatory mediator IL-1β
increased more than 6-fold and TNF-α30-fold (p = 0.001). Extracted spores had a minimal effect on all examined parameters
in BAL fluid indicating that mycotoxins are primarily responsible for the hemorrhagic and inflammatory response.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
110.
Sarah M. Nour John R. Lawrence Hong Zhu George D. W. Swerhone Martha Welsh Tom W. Welacky Edward Topp 《Applied microbiology》2003,69(1):607-615
The soybean cyst nematode (SCN), Heterodera glycines, causes economically significant damage to soybeans (Glycine max) in many parts of the world. The cysts of this nematode can remain quiescent in soils for many years as a reservoir of infection for future crops. To investigate bacterial communities associated with SCN cysts, cysts were obtained from eight SCN-infested farms in southern Ontario, Canada, and analyzed by culture-dependent and -independent means. Confocal laser scanning microscopy observations of cyst contents revealed a microbial flora located on the cyst exterior, within a polymer plug region and within the cyst. Microscopic counts using 5-(4,6-dichlorotriazine-2-yl)aminofluorescein staining and in situ hybridization (EUB 338) indicated that the cysts contained (2.6 ± 0.5) × 105 bacteria (mean ± standard deviation) with various cellular morphologies. Filamentous fungi were also observed. Live-dead staining indicated that the majority of cyst bacteria were viable. The probe Nile red also bound to the interior polymer, indicating that it is lipid rich in nature. Bacterial community profiles determined by denaturing gradient gel electrophoresis analysis were simple in composition. Bands shared by all eight samples included the actinobacterium genera Actinomadura and Streptomyces. A collection of 290 bacteria were obtained by plating macerated surface-sterilized cysts onto nutrient broth yeast extract agar or on actinomycete medium. These were clustered into groups of siblings by repetitive extragenic palindromic PCR fingerprinting, and representative isolates were tentatively identified on the basis of 16S rRNA gene sequence. Thirty phylotypes were detected, with the collection dominated by Lysobacter and Variovorax spp. This study has revealed the cysts of this important plant pathogen to be rich in a variety of bacteria, some of which could presumably play a role in the ecology of SCN or have potential as biocontrol agents. 相似文献