Ecology Letters (2012)
Trees with sufficient nutrition are known to allocate carbon preferentially to aboveground plant parts. Our global study of 49 forests revealed an even more fundamental carbon ...allocation response to nutrient availability: forests with high‐nutrient availability use 58 ± 3% (mean ± SE; 17 forests) of their photosynthates for plant biomass production (BP), while forests with low‐nutrient availability only convert 42 ± 2% (mean ± SE; 19 forests) of annual photosynthates to biomass. This nutrient effect largely overshadows previously observed differences in carbon allocation patterns among climate zones, forest types and age classes. If forests with low‐nutrient availability use 16 ± 4% less of their photosynthates for plant growth, what are these used for? Current knowledge suggests that lower BP per unit photosynthesis in forests with low‐ versus forests with high‐nutrient availability reflects not merely an increase in plant respiration, but likely results from reduced carbon allocation to unaccounted components of net primary production, particularly root symbionts.
Half‐hourly measurements of the net exchanges of carbon dioxide and water vapor between terrestrial ecosystems and the atmosphere provide estimates of gross primary production (GPP) and ...evapotranspiration (ET) at the ecosystem level and on daily to annual timescales. The ratio of these quantities represents ecosystem water use efficiency. Its multiplication with mean daylight vapor pressure deficit (VPD) leads to a quantity which we call “inherent water use efficiency” (IWUE*). The dependence of IWUE* on environmental conditions indicates possible adaptive adjustment of ecosystem physiology in response to a changing environment. IWUE* is analyzed for 43 sites across a range of plant functional types and climatic conditions. IWUE* increases during short‐term moderate drought conditions. Mean annual IWUE* varied by a factor of 3 among all sites. This is partly explained by soil moisture at field capacity, particularly in deciduous broad‐leaved forests. Canopy light interception sets the upper limits to canopy photosynthesis, and explains half the variance in annual IWUE* among herbaceous ecosystems and evergreen needle‐leaved forests. Knowledge of IWUE* offers valuable improvement to the representation of carbon and water coupling in ecosystem process models.
Aggressive cancers often express E-cadherin in cytoplasmic vesicles rather than on the plasma membrane and this may contribute to the invasive phenotype of these tumors. Therapeutic strategies are ...not currently available that restore the anti-invasive function of E-cadherin in cancers. MDA-MB-231 cells are a frequently used model of invasive triple-negative breast cancer, and these cells express low levels of E-cadherin that is mislocalized to cytoplasmic vesicles. MDA-MB-231 cell lines stably expressing wild-type E-cadherin or E-cadherin fused to glutathione S-transferase or green fluorescent protein were used as experimental systems to probe the mechanisms responsible for cytoplasmic E-cadherin localization in invasive cancers. Although E-cadherin expression partly reduced cell invasion in vitro, E-cadherin was largely localized to the cytoplasm and did not block the invasiveness of the corresponding orthotopic xenograft tumors. Further studies indicated that the glucocorticoid dexamethasone and the highly potent class I histone deacetylase (HDAC) inhibitor largazole cooperated to induce E-cadherin localization to the plasma membrane in triple-negative breast cancers, and to suppress cellular invasion in vitro. Dexamethasone blocked the production of the cleaved form of the CDCP1 (that is, CUB domain-containing protein 1) protein (cCDCP1) previously implicated in the pro-invasive activities of CDCP1 by upregulating the serine protease inhibitor plasminogen activator inhibitor-1. E-cadherin preferentially associated with cCDCP1 compared with the full-length form. In contrast, largazole did not influence CDCP1 cleavage, but increased the association of E-cadherin with γ-catenin. This effect on E-cadherin/γ-catenin complexes was shared with the nonisoform selective HDAC inhibitors trichostatin A (TSA) and vorinostat (suberoylanilide hydroxamic acid, SAHA), although largazole upregulated endogenous E-cadherin levels more strongly than TSA. These results demonstrate that glucocorticoids and HDAC inhibitors, both of which are currently in clinical use, cooperate to suppress the invasiveness of breast cancer cells through novel, complementary mechanisms that converge on E-cadherin.
Drought and ecosystem carbon cycling van der Molen, M.K.; Dolman, A.J.; Ciais, P. ...
Agricultural and forest meteorology,
07/2011, Letnik:
151, Številka:
7
Journal Article
Recenzirano
► Intermittent droughts interact differently with the carbon cycle than gradual change. ► Direct effects on carbon exchange depend strongly on vegetation species strategie. ► Drought induced ...mortality is species sensitive and gives rise to competition. ► Disturbed nutrient and carbohydrate reservoirs cause carry-over effects. ► Models need to simulate these longer-term climate-carbon cycle feedbacks.
Drought as an intermittent disturbance of the water cycle interacts with the carbon cycle differently than the ‘gradual’ climate change. During drought plants respond physiologically and structurally to prevent excessive water loss according to species-specific water use strategies. This has consequences for carbon uptake by photosynthesis and release by total ecosystem respiration. After a drought the disturbances in the reservoirs of moisture, organic matter and nutrients in the soil and carbohydrates in plants lead to longer-term effects in plant carbon cycling, and potentially mortality. Direct and carry-over effects, mortality and consequently species competition in response to drought are strongly related to the survival strategies of species. Here we review the state of the art of the understanding of the relation between soil moisture drought and the interactions with the carbon cycle of the terrestrial ecosystems. We argue that plant strategies must be given an adequate role in global vegetation models if the effects of drought on the carbon cycle are to be described in a way that justifies the interacting processes.
Background: Mammary metaplastic carcinoma encompasses epithelial-only carcinoma (high-grade adenosquamous carcinoma or pure squamous cell carcinoma), biphasic epithelial and sarcomatoid carcinoma and ...monophasic spindle cell carcinoma. Aim: To evaluate the clinicopathological features of a large series of 34 metaplastic carcinomas. Methods: 10 epithelial-only, 14 biphasic and 10 monophasic metaplastic carcinomas were assessed for nuclear grade, hormone receptor status, HER2/neu (cerbB2) oncogene expression, Ki-67 and p53, lymph node status and recurrence on follow-up. Results: Intermediate to high nuclear grade were assessed in most (33/34) tumours. Oestrogen and progesterone receptors were negative in 8 of 10 epithelial-only, all 14 biphasic, and 9 of 10 monophasic tumours, cerbB2 was negative in 7 of 10 epithelial-only, all 14 biphasic and 8 of 10 monophasic tumours. Ki-67 was found to be positive in 6 of 10 epithelial-only, 6 of 14 biphasic, and 7 of 10 monophasic tumours, whereas p53 was positive in 6 of 10 epithelial-only, 7 of 14 biphasic, and 8 of 10 monophasic tumours. Lymph node metastases were seen in 7 of 7 epithelial-only, 7 of 11 biphasic, and 3 of 7 monophasic tumours. Recurrences were seen in 4 of 7 epithelial-only, 8 of 9 biphasic, and 4 of 9 monophasic tumours. Conclusions: All three subtypes of metaplastic carcinoma are known to behave aggressively, and should be differentiated from the low-grade fibromatosis-like metaplastic carcinoma, which does not metastasise. Oncological treatment options may be limited by the frequently negative status of hormonal receptor and cerbB2.
Ethnic minority women experience disparities in mammography screening utilisation and breast cancer outcomes. This systematic review and meta-analysis synthesised multidomain and multilevel factors ...that intersect to influence the utilisation of mammography among ethnic minorities. A literature search was conducted in five databases (PubMed, Ovid MEDLINE, EMBASE, CINAHL, and PsycINFO) from inception to May 2022. Guided by the National Institute on Minority Health and Health Disparity research framework, the retrieved data were synthesised using narrative summaries and meta-analyses. Among the 27 studies, most (n = 24) reported individual, interpersonal, and community factors in the health care system domain. In the sociocultural domain, interpersonal and societal (n = 8) factors, such as modesty and karma beliefs, were less frequently identified than individual (n = 20) factors in relation to acculturation. Only individual-level factors were reported for the biological and physical/built environment (e.g., rural residence) domains. In the behavioural domain, cancer screening behaviours had a high combined prediction ability (odds ratio = 18.23;
I
2
= 23%), whereas interpersonal (e.g., family obligations) and community (e.g., neighbourhood violence) factors discouraged mammography screening. Special focus should be given to ethnic minority women, especially those living in rural areas, those with considerable family obligations, and those who have suffered from violence and other life pressures, to increase their access to mammography services. Multidomain and multilevel efforts, culturally appropriate strategies, and equity-advancing policies such as geographic access and insurance coverage would help to mitigate the ethnic disparities in mammography screening.
•Mortality rates in PNW US forests (0.5–1.35%) are consistent with historical means.•Wildfires do not greatly reduce forest C storage, which is mostly in soil and wood.•Long rotations accumulate more ...carbon than short rotations, and reduce C emissions.•Forest composition is likely to continue to change under future climate (e.g., BC).•Recent models and remote sensing make them relevant to managers.
Climate change has already begun to impact the structure and function of forest ecosystems in the Pacific Northwest by altering the frequency, intensity, and duration of droughts and heat stress, with implications for widespread environmental and socio-economic change. A major realization is that accumulated physiological stress can ultimately lead to tree mortality and changes in species distributions, particularly in areas away from maritime influences. To ameliorate the effects of drought, insect outbreaks, and reduce the risk of crown fires, various strategies are being tested. To make some of these strategies economical, biomass is proposed as an alternative energy source. At the same time that an increase in harvesting is being considered, there is a desire to increase carbon sequestration by forests to offset, at least in part, greenhouse gas emissions. Assessments are needed to determine current and future impacts of climate change, and to evaluate management options while considering carbon storage benefits and sustainability of ecosystem structure and function. Here we provide an overview of research results from the Pacific Northwest region where forests dominate the landscape and contain among the highest biomass on earth. In this review, we present findings that challenge common assumptions, and suggest a way to predict outcomes of changes in climate and land management in the future. The approach includes the use of observation-driven land system models that integrate the extent that forests are vulnerable to climate change, management practices, and economic considerations. It also requires increased emphasis on in situ and remotely sensed observations and experiments to initialize and test the model, and to track trends in forest condition.
Epithelial-mesenchymal transition (EMT) has pivotal roles during embryonic development and carcinoma progression. Members of the Snai1 family of zinc finger transcription factors are central ...mediators of EMT and induce EMT in part by directly repressing epithelial markers such as E-cadherin, a gatekeeper of the epithelial phenotype and a suppressor of tumor invasion. However, the molecular mechanism underlying Snai1-mediated transcriptional repression remains incompletely understood. Here we show that Snai1 physically interacts with and recruits the histone demethylase LSD1 (KDM1A) to epithelial gene promoters. LSD1 removes dimethylation of lysine 4 on histone H3 (H3K4m2), a covalent histone modification associated with active chromatin. Importantly, LSD1 is essential for Snai1-mediated transcriptional repression and for maintenance of the silenced state of Snai1 target genes in invasive cancer cells. In the absence of LSD1, Snai1 fails to repress E-cadherin. In cancer cells in which E-cadherin is silenced, depletion of LSD1 results in partial de-repression of epithelial genes and elevated H3K4m2 levels at the E-cadherin promoter. These results underline the critical role of LSD1 in Snai1-dependent transcriptional repression of epithelial markers and suggest that the LSD1 complex could be a potential therapeutic target for prevention of EMT-associated tumor invasion.
Epithelial-mesenchymal transition (EMT) has pivotal roles during embryonic development and carcinoma progression. Members of the Snai1 family of zinc finger transcription factors are central ...mediators of EMT and induce EMT in part by directly repressing epithelial markers such as E-cadherin, a gatekeeper of the epithelial phenotype and a suppressor of tumor invasion. However, the molecular mechanism underlying Snai1-mediated transcriptional repression remains incompletely understood. Here we show that Snai1 physically interacts with and recruits the histone demethylase LSD1 (KDM1A) to epithelial gene promoters. LSD1 removes dimethylation of lysine 4 on histone H3 (H3K4m2), a covalent histone modification associated with active chromatin. Importantly, LSD1 is essential for Snai1-mediated transcriptional repression and for maintenance of the silenced state of Snai1 target genes in invasive cancer cells. In the absence of LSD1, Snai1 fails to repress E-cadherin. In cancer cells in which E-cadherin is silenced, depletion of LSD1 results in partial de-repression of epithelial genes and elevated H3K4m2 levels at the E-cadherin promoter. These results underline the critical role of LSD1 in Snai1-dependent transcriptional repression of epithelial markers and suggest that the LSD1 complex could be a potential therapeutic target for prevention of EMT-associated tumor invasion. Oncogene (2010) 29, 4896-1904; doi: 10.1038/onc.2010.234; published online 21 June 2010 Keywords: EMT; E-cadherin; Snail; histone modifications; LSD1; bivalent
Self-efficacy has been consistently found to be a protective factor against psychological distress and disorders in the literature. However, little research is done on the moderating effect of ...self-efficacy on depressive symptoms in the context of chronic pain. This cross-sectional study aimed to examine if pain self-efficacy attenuated the direct relationship between pain intensity and depressive symptoms, as well as their indirect relationship through reducing the extent of catastrophizing when feeling pain (moderated mediation). 664 community-dwelling Chinese older adults aged 60-95 years who reported chronic pain for at least three months were recruited from social centers. They completed a battery of questionnaires on chronic pain, pain self-efficacy, catastrophizing, and depressive symptoms in individual face-to-face interviews. Controlling for age, gender, education, self-rated health, number of chronic diseases, pain disability, and pain self-efficacy, pain catastrophizing was found to partially mediate the connection between pain intensity and depressive symptoms. Furthermore, the relationship between pain intensity and depressive symptoms was moderated by pain self-efficacy. Self-efficacy was also found to moderate the relationship between pain intensity and catastrophizing and the moderated mediation effect was confirmed using bootstrap analysis. The results suggested that with increasing levels of self-efficacy, pain intensity's direct effect on depressive symptoms and its indirect effect on depressive symptoms via catastrophizing were both reduced in a dose-dependent manner. Our findings suggest that pain self-efficacy is a significant protective factor that contributes to psychological resilience in chronic pain patients by attenuating the relationship of pain intensity to both catastrophizing and depressive symptoms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
