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111.
Seed dispersal often limits tropical forest regeneration and animals disperse most rainforest tree seeds. This presents two important questions for restoration ecologists: (1) which animals are common seed dispersers? and (2) which restoration techniques attract them? Fourteen restoration sites were planted with four tree species in three designs, (1) controls (no planting, natural regeneration) (2) islands (trees planted in small patches), and (3) plantations (trees planted continuously over a large patch). We sampled birds in November, February, and April 2007–2008 with mist nets, in February and July 2009 with observations, and in July 2008 with both techniques. We documented 30 seed species from fecal samples of captured birds. All identified seed species were early‐successional forms. Four tanager species, three thrushes, two saltators, two flycatchers, and one finch were categorized as common seed dispersers, based on their high likelihood of dispersing seeds. Common dispersers were generalist species with small gape widths (<15 mm). Common dispersers were captured significantly more often in plantations than controls in most seasons and more often in plantations than islands during one season. Common disperser observations were significantly greater in plantations than controls during two periods and in plantations compared with islands in one period. Results indicate that plantation‐style planting is the conservative strategy to maximize attractiveness to common dispersers in tropical restoration sites. Island planting is an alternative when resources are limited although disperser activity may be lower in some seasons than in plantations. Additional research should investigate how to attract large, forest‐associated dispersers. 相似文献
112.
Ferris M. Pfeiffer Theodore J. Choma Rebecca Kueny 《Computer methods in biomechanics and biomedical engineering》2013,16(13):1459-1467
A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2–5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad–caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force. 相似文献
113.
Fabio Casu Rebecca K. Harston Maria A. Chiacchio Giuseppe Gumina 《Nucleosides, nucleotides & nucleic acids》2013,32(3):224-235
2′-Modified inosine analogs have been synthesized from 6-chloropurine riboside via 6-dimethylaminopurine or 6-benzyloxypurine intermediates. The dimethylaminopurine intermediate was obtained via an unusually facile dimethylamine transfer from dimethylformamide. Graphical Abstract: 相似文献
114.
Rebecca E. Williams Lisa Cottrell Matthew Jacobsen Lasantha R. Bandara Mike D. Kelly Sandy Kennedy 《Biomarkers》2013,18(6):472-490
N-Phenylanthranilic acid (NPAA) causes renal papillary necrosis (RPN) in the rat following repeated oral dosing. Non-invasive early detection of RPN is difficult, but a number of potential biomarkers have been investigated, including phospholipid and uronic acid excretion. This study used 1H-nuclear magnetic resonance (NMR) spectroscopic analysis of urine to investigate urinary metabolic perturbations occurring in the rat following exposure to NPAA. Male Alderley Park rats received NPAA (300, 500 or 700?mg?kg?1?day?1 orally) for 7?days, and urine was collected on days 7–8, 14–15, 21–22 and 28–29. In a separate study, urine was collected on days 1–2, 3–4, 5–6 and 7–8 from rats receiving 500?mg?kg?1?day?1. Samples were analysed by 1H NMR spectroscopy combined with multivariate data analysis and clinical chemistry. Histopathology and clinical chemistry analysis of terminal blood samples was carried out following termination on days 4, 6, 8 and 29 (4?week time course) and days 2, 4, 6 and 8 (8?day study). Urine analysis revealed a marked, though variable, excretion of β-hydroxybutyrate, acetoacetate and acetone (ketone bodies) seen on days 3–4, 5–6 and 7–8 of the study. It is postulated that the ketonuria might be secondary to an alteration in fatty acid metabolism due to inhibition of prostaglandin synthesis. In addition, an elevation in urinary ascorbate was observed during the first 8?days of the study. Ascorbate is considered to be a biomarker of hepatic response, probably reflecting an increased hepatic activity due to glucuronidation of NPAA. 相似文献
115.
Grassland productivity in response to climate change and land use is a global concern. In order to explore the effects of climate change and land use on net primary productivity (NPP), NPP partitioning [fBNPP, defined as the fraction of belowground NPP (BNPP) to NPP], and rain‐use efficiency (RUE) of NPP, we conducted a field experiment with warming (+3 °C), altered precipitation (double and half), and annual clipping in a mixed‐grass prairie in Oklahoma, USA since July, 2009. Across the years, warming significantly increased BNPP, fBNPP, and RUEBNPP by an average of 11.6%, 2.8%, and 6.6%, respectively. This indicates that BNPP was more sensitive to warming than aboveground NPP (ANPP) since warming did not change ANPP and RUEANPP much. Double precipitation stimulated ANPP, BNPP, and NPP but suppressed RUEANPP, RUEBNPP, and RUENPP while half precipitation decreased ANPP, BNPP, and NPP but increased RUEANPP, RUEBNPP, and RUENPP. Clipping interacted with altered precipitation in impacting RUEANPP, RUEBNPP, and RUENPP, suggesting land use could confound the effects of precipitation changes on ecosystem processes. Soil moisture was found to be a main factor in regulating variation in ANPP, BNPP, and NPP while soil temperature was the dominant factor influencing fBNPP. These findings suggest that BNPP is critical point to future research. Additionally, results from single‐factor manipulative experiments should be treated with caution due to the non‐additive interactive effects of warming with altered precipitation and land use (clipping). 相似文献
116.
Biobanks are increasingly being established to act as mediators between patient-donors and researchers. In practice, some of these will close. This paper details the experiences of one such bank. We report interviews with the bank's staff and oversight group during the period when the bank ceased biobanking activity, reconfigured as a disseminator of best practice, before then closing altogether. The paper makes three distinct contributions: (i) to provide a detailed account of the establishment, operational challenges, and eventual closure of the bank, which makes clear the rapid turnover in a cycle of promise and disappointment; (ii) to explore this in terms of a novel analytical focus upon field, institutional, and individual expectations; and (iii) to use this typology to demonstrate how, even after the bank's closure, aspects of its work were reconfigured and reused in new contexts. This provides a unique empirical analysis of the under-reported issue of biobank closure. 相似文献
117.
Mark Jones Marileila Varella-Garcia Margaret Skokan Steven Bryce Jeffrey Schowinsky Rebecca Peters Boah Vang Michelle Brecheisen Thomas Startz Nathan Frank Brian Nankervis 《Cytotherapy》2013,15(11):1323-1339
Background aimsThe Quantum® Cell Expansion System (Quantum; Terumo BCT, Inc, Lakewood, CO, USA) is a novel hollow fiber-based device that automates and closes the cell culture process, reducing labor intensive tasks such as manual cell culture feeding and harvesting. The manual cell selection and expansion processes for the production of clinical-scale quantities of bone marrow-derived human mesenchymal stromal cells (BM-hMSCs) have been successfully translated onto the Quantum platform previously. The formerly static, manual, in vitro process performed primarily on tissue culture polystyrene substrates may raise the question of whether BM-hMSCs cultured on a hollow fiber platform yields comparable cell quality.MethodsA rigorous battery of assays was used to determine the genetic stability of BM-hMSCs selected and produced with the Quantum. In this study, genetic stability was determined by assessing spectral karyotype, micronucleus formation and tumorigenicity to resolve chromosomal aberrations in the stem cell population. Cell phenotype, adherent growth kinetics and tri-lineage differentiation were also evaluated. HMSC bone marrow aspirates, obtained from three approved donors, were expanded in parallel using T225 culture flasks and the Quantum.ResultsBM-hMSCs harvested from the Quantum demonstrated immunophenotype, morphology and tri-lineage differentiation capacity characteristics consistent with the International Society of Cell Therapy standard for hMSCs. Cell populations showed no malignant neoplastic formation in athymic mice 60 days post-transplant, no clonal chromosomal aberrations were observed and no DNA damage was found as measured by micronucleus formation.ConclusionsQuantum-produced BM-hMSCs are of comparable quality and demonstrate analogous genetic stability to BM-hMSCs cultured on tissue culture polystyrene substrates. 相似文献
118.
Rebecca Lamb Sophie Lehn Lynsey Rogerson Robert B Clarke G?ran Landberg 《Cell cycle (Georgetown, Tex.)》2013,12(15):2384-2394
Cyclin D1 and its binding partners CDK4/6 are essential regulators of cell cycle progression and are implicated in cancer progression. Our aim was to investigate a potential regulatory role of these proteins in other essential tumor biological characteristics. Using a panel of breast cancer cell lines and primary human breast cancer samples, we have demonstrated the importance of these cell cycle regulators in both migration and stem-like cell activity. siRNA was used to target cyclin D1 and CDK4/6 expression, having opposing effects on both migration and stem-like cell activity dependent upon estrogen receptor (ER) expression. Inhibition of cyclin D1 or CDK4/6 increases or decreases migration and stem-like cell activity in ER−ve (ER-negative) and ER+ve (ER-positive) breast cancer, respectively. Furthermore, overexpressed cyclin D1 caused decreased migration and stem-like cell activity in ER−ve cells while increasing activity in ER+ve breast cancer cells. Treatment of breast cancer cells with inhibitors of cyclin D1 and CDK4/6 (Flavopiridol/PD0332991), currently in clinical trials, mimicked the effects observed with siRNA treatment. Re-expression of ER in two ER−ve cell lines was sufficient to overcome the effects of either siRNA or clinical inhibitors of cyclin D1 and CDK4/6.
In conclusion, cyclin D1 and CDK4/6 have alternate roles in regulation of migration and stem-like cell activity. Furthermore, these effects are highly dependent upon expression of ER. The significance of these results adds to our general understanding of cancer biology but, most importantly, could be used diagnostically to predict treatment response to cell cycle inhibition in breast cancer. 相似文献
119.
Ahmed F. Salem Mazhar Salim Al-Zoubi Diana Whitaker-Menezes Ubaldo E. Martinez-Outschoorn Rebecca Lamb James Hulit Anthony Howell Ricardo Gandara Marina Sartini Ferruccio Galbiati Generoso Bevilacqua Federica Sotgia Michael P. Lisanti 《Cell cycle (Georgetown, Tex.)》2013,12(5):818-825
Cigarette smoke has been directly implicated in the disease pathogenesis of a plethora of different human cancer subtypes, including breast cancers. The prevailing view is that cigarette smoke acts as a mutagen and DNA damaging agent in normal epithelial cells, driving tumor initiation. However, its potential negative metabolic effects on the normal stromal microenvironment have been largely ignored. Here, we propose a new mechanism by which carcinogen-rich cigarette smoke may promote cancer growth, by metabolically “fertilizing” the host microenvironment. More specifically, we show that cigarette smoke exposure is indeed sufficient to drive the onset of the cancer-associated fibroblast phenotype via the induction of DNA damage, autophagy and mitophagy in the tumor stroma. In turn, cigarette smoke exposure induces premature aging and mitochondrial dysfunction in stromal fibroblasts, leading to the secretion of high-energy mitochondrial fuels, such as L-lactate and ketone bodies. Hence, cigarette smoke induces catabolism in the local microenvironment, directly fueling oxidative mitochondrial metabolism (OXPHOS) in neighboring epithelial cancer cells, actively promoting anabolic tumor growth. Remarkably, these autophagic-senescent fibroblasts increased breast cancer tumor growth in vivo by up to 4-fold. Importantly, we show that cigarette smoke-induced metabolic reprogramming of the fibroblastic stroma occurs independently of tumor neo-angiogenesis. We discuss the possible implications of our current findings for the prevention of aging-associated human diseases and, especially, common epithelial cancers, as we show that cigarette smoke can systemically accelerate aging in the host microenvironment. Finally, our current findings are consistent with the idea that cigarette smoke induces the “reverse Warburg effect,” thereby fueling “two-compartment tumor metabolism” and oxidative mitochondrial metabolism in epithelial cancer cells. 相似文献
120.
Ru Wang Markku Alen Zhusheng Yu Petri Wiklund Shu Mei Cheng Timo T?rm?kangas Peijie Chen Sulin Cheng 《PloS one》2013,8(12)
Vitamin D is well known for its regulatory role in calcium and phosphate homeostasis, but its role in muscle mass and strength during growth remains inconclusive. We explored the association of serum 25-hydroxyvitamin D (25(OH)D) with muscle development in girls from 11 to 18-years old. Whole body lean tissue mass (LMWB), appendicular lean mass (aLM), muscle cross-sectional area at the lower leg (mCSA), maximal voluntary contraction of elbow flexors (MVCelbow) and knee extensors (MVCknee) were assessed in 217 girls aged 10–13 years (at baseline), 215 in 2-year and 226 in 7.5-year follow-up. Serum concentration of 25(OH)D and intact parathyroid hormone (PTH) were analyzed retrospectively and girls were categorized according to their 25(OH)D levels (consistently insufficient 25(OH)D GLL <50 nmol/l and consistently sufficient GHH >50 nmol/l from baseline to 7-year follow-up). We found that 25(OH)D level declined until menarche (p<0.05) while LMWB, aLM, mCSA, MVCelbow and MVCknee continued to increase (p<0.001 for all) post menarche. At pre-menarche, the GLL (n = 34) had higher LMWB and aLM than the GHH (n = 21, p<0.05), while post-menarche the GHH (n = 15) had a greater catch-up gain in LMWB (p = 0.004), aLM (p = 0.001) and mCSA (p = 0.027) compared to the GLL (n = 65) over the first 2-year period. At the age of 18, no differences in muscle mass/strength between the low (n = 151) and high (n = 77) levels of 25(OH)D groups were found. This finding was independent of vitamin D receptor genotype and other confounders. In conclusion, our results showed that levels of 25(OH)D have no significant negative influence on the development of muscle mass and strength during pubertal growth both with longitudinal and cross-sectional comparison. On the contrary, our results suggest that the temporary negative association between 25(OH)D and muscle mass arises as a consequence of fast growth prior to menarche, and this negative association is diminished through catch-up growth after menarche. 相似文献