Forest disturbance leads to the rapid spread of the invasive leucaena leucocephala in Taiwan

This study, based on different investigative documents and analytical methods, elucidates spatial distribution of habitats for major invasive exotic plants, Leucaena leucocephala, in Taiwan. Results show that Leucaena leucocephala is most harmful to broad-leaved trees and its invasion directly relates to changes in the physical environment. Leucaena leucocephala can bloom and bear fruits all year round and during the period of seeds sprouting and saplings, the invasion varies greatly among different soil types. Leucaena leucocephala prefers weakly acidic soil, though it grows well with other soil textures and nutrients as well. The average spreading rate of Leucaena leucocephala is 3.55 ha year-1 on abandoned farm land calculated from the aerial photographs taken in 1982, 1992, 2003, and 2007

Temperature and sheltering determine patterns of seedling establishment in an advancing subtropical treeline

Questions: An advance of high-altitude treelines has been reported in response to warming climate throughout the globe. Understanding local controls on the establishment of seedlings above the treeline is essential for predicting wider patterns of treeline response from a process-based perspective. Here we investigate patterns of seedling establishment in relation to microsite conditions in an advancing treeline ecotone in the subtropics, using climate data recorded at the plant-relevant scale. We sought to determine which temperature factors were of importance, if sheltering plays an important role in seedling establishment and if the response varied with seedling age. Location: The Abies kawakamii treelines of the Central Mountain Range, Taiwan, 2800 to 3275m a.s.l. Methods: Seedlings were monitored in plots covering a range of treeline structural forms over a period of 2yrs. Temperatures were recorded at plant-relevant height (5cm) above ground and depth below ground with data loggers. Microtopographic sheltering (at a 10-m scale) and surrounding vegetation were measured. The influence of the above variables on seedling number and growth was investigated using generalized linear models and linear mixed effect models, respectively. Results: Soil temperatures had more influence on seedling number than air temperature, whilst air temperature was positively associated with subsequent seedling growth. Establishment patterns were found to have a strong relationship with microtopographic sheltering, with more sheltered areas having elevated seedling numbers. Early growth may have significant implications for subsequent plant performance since smaller seedlings were more sensitive to both temperature and microtopography than larger seedlings. Conclusions: Air and soil temperatures and microtopography determine spatial patterns of seedling establishment. Our results suggest that establishment above the treeline is likely to continue as the climate warms, although advance will not be spatially uniform due to the modifying influence of topography. This variability has important implications for the persistence and extinction of alpine plant communities occurring above treeline in topographically complex systems

Community change and species richness reductions in rapidly advancing tree lines

Aim: Climate change is causing shifts in the range of species worldwide. In high altitude areas forests are often observed to be shifting their upper limits to higher altitudes in response to warming temperatures. Although this phenomenon is well described, the possible consequences of this for the wider forest community have not been fully considered. In this study we use epiphytic macro-lichens to investigate the impacts of treeline advance on associated organisms. We hypothesized that the rate of forest advance should influence the species richness and composition of associated communities.  Location: The Hehuanshan area, Central Mountain Range, Taiwan (24°08–09’ N, 121°15 – 16’ E).  Methods: Lichen communities were sampled on trees occurring at 33 treeline sites displaying varying degrees of advance. Habitat variables were recorded. ANOVA, GLMM, nestedness analysis and indicator species analysis were used to investigate patterns of species richness and community composition and their association with treeline advance and habitat variables.  Results: Species richness was lower in treelines exhibiting rapid advance; reductions were related to tree size (considered here as a proxy for age) and the distance over which advance had occurred. Community composition varied with treeline form and forest position. Only a subset of species found in slowly advancing or stable forest edges occurred in rapidly advancing treelines.  Main conclusions: Differential migration rates between co-occurring species and differences in habitat structure associated with treeline advance can result in community change, but this depends, amongst other factors, on the speed of treeline advance. The importance of advance rate in determining the response suggests that reductions in species richness at treeline could be transitory. However, this will depend on whether advance continues, and on the changes in habitat associated with advance. Given the complexity of treeline behaviour, the findings that we report represent an essential step in understanding community responses to climate change. This understanding is of importance for biodiversity and conservation, especially given the high rate of endemism reported for this and other alpine regions

An Evolutionary Perspective of Pierce’s Disease of Grapevine, Citrus Variegated Chlorosis, and Mulberry Leaf Scorch Diseases

Xylella fastidiosa causes diseases on a growing list of economically important plants. An understanding of how xylellae diseases originated and evolved is important for disease prevention and management. In this study, we evaluated the phylogenetic relationships of X. fastidiosa strains from citrus, grapevine, and mulberry through the analyses of random amplified polymorphic DNAs (RAPDs) and conserved 16S rDNA genes. RAPD analysis emphasized the vigorous genome-wide divergence of X. fastidiosa and detected three clonal groups of strains that cause Pierce’s disease (PD) of grapevine, citrus variegated chlorosis (CVC), and mulberry leaf scorch (MLS). Analysis of 16S rDNA sequences also identified the PD and CVC groups, but with a less stable evolutionary tree. MLS strains were included in the PD group by the 16S rDNA analysis. The Asiatic origins of the major commercial grape and citrus cultivars suggest the recent evolution of both PD and CVC disease in North and South America, respectively, since X. fastidiosa is a New World organism. In order to prevent the development of new diseases caused by X. fastidiosa, it is important to understand the diversity of X. fastidiosa strains, how strains of X. fastidiosa select their hosts, and their ecological roles in the native vegetation

Epigenetic Effects and Molecular Mechanisms of Tumorigenesis Induced by Cigarette Smoke: An Overview

Cigarette smoking is one of the major causes of carcinogenesis. Direct genotoxicity induced by cigarette smoke leads to initiation of carcinogenesis. Nongenotoxic (epigenetic) effects of cigarette smoke also act as modulators altering cellular functions. These two effects underlie the mechanisms of tumor promotion and progression. While there is no lack of general reviews on the genotoxic and carcinogenic potentials of cigarette smoke in lung carcinogenesis, updated review on the epigenetic effects and molecular mechanisms of cigarette smoke and carcinogenesis, not limited to lung, is lacking. We are presenting a comprehensive review of recent investigations on cigarette smoke, with special attentions to nicotine, NNK, and PAHs. The current understanding on their molecular mechanisms include (1) receptors, (2) cell cycle regulators, (3) signaling pathways, (4) apoptosis mediators, (5) angiogenic factors, and (6) invasive and metastasis mediators. This review highlighted the complexity biological responses to cigarette smoke components and their involvements in tumorigenesis

An Integrated Bus and Taxi Routes for a Mobile Trip Planning System

With the popular usage of Google Maps and smart phones, more and more people are using smart phones to surf and inquire about travel information. As a result, every major city plans to push the existing online public transportation trip planning system beyond traditional computer users to mobile phone users. The trip planning system is based on the starting and ending points that a user inputs, and guides the user to take a bus or metro through an electronic map interface. The system usually provides different kind of alternative travel routes with the estimated time of arrival. However, people who use the public transport system may encounter some uncertainties, such as long waiting times, long routes, long walking distances, etc. In each big city, the taxi is a universal transport vehicle which is available at almost anytime, anywhere. Taxis can save passengers’ walking distance and travel time with a deficit of high cost. Therefore, we design a trip planning system to unify the Taipei public transportation system with taxis. The users can inquire of a travel route through the mobile phones. This system uses Google Maps as a base map. The users assign an upper limit of fare which they are willing to pay. The system will balance between travel time and travel cost to obtain a route which may combine usage of the bus and taxi. Because of the high density of bus stations in Taipei city, the route search may consume a lot of system resources. We propose an improvement method to eliminate some intermediate bus stations in route search processing

Comparative global immune-related gene profiling of somatic cells, human pluripotent stem cells and their derivatives: implication for human lymphocyte proliferation.

Human pluripotent stem cells (hPSCs), including embryonic stem cells (ESCs) and induced PSCs (iPSCs), represent potentially unlimited cell sources for clinical applications. Previous studies have suggested that hPSCs may benefit from immune privilege and limited immunogenicity, as reflected by the reduced expression of major histocompatibility complex class-related molecules. Here we investigated the global immune-related gene expression profiles of human ESCs, hiPSCs and somatic cells and identified candidate immune-related genes that may alter their immunogenicity. The expression levels of global immune-related genes were determined by comparing undifferentiated and differentiated stem cells and three types of human somatic cells: dermal papilla cells, ovarian granulosa cells and foreskin fibroblast cells. We identified the differentially expressed genes CD24, GATA3, PROM1, THBS2, LY96, IFIT3, CXCR4, IL1R1, FGFR3, IDO1 and KDR, which overlapped with selected immune-related gene lists. In further analyses, mammalian target of rapamycin complex (mTOR) signaling was investigated in the differentiated stem cells following treatment with rapamycin and lentiviral transduction with specific short-hairpin RNAs. We found that the inhibition of mTOR signal pathways significantly downregulated the immunogenicity of differentiated stem cells. We also tested the immune responses induced in differentiated stem cells by mixed lymphocyte reactions. We found that CD24- and GATA3-deficient differentiated stem cells including neural lineage cells had limited abilities to activate human lymphocytes. By analyzing the transcriptome signature of immune-related genes, we observed a tendency of the hPSCs to differentiate toward an immune cell phenotype. Taken together, these data identify candidate immune-related genes that might constitute valuable targets for clinical applications

High ERCC1 expression predicts cisplatin-based chemotherapy resistance and poor outcome in unresectable squamous cell carcinoma of head and neck in a betel-chewing area

<p>Abstract</p> <p>Background</p> <p>This study was to evaluate the effect of excision repair cross-complementation group 1(ERCC1) expression on response to cisplatin-based induction chemotherapy (IC) followed by concurrent chemoradiation (CCRT) in locally advanced unresectable head and neck squamous cell carcinoma (HNSCC) patients.</p> <p>Methods</p> <p>Fifty-seven patients with locally advanced unresectable HNSCC who received cisplatin-based IC followed by CCRT from January 1, 2006 through January 1, 2008. Eligibility criteria included presence of biopsy-proven HNSCC without a prior history of chemotherapy or radiotherapy. Immunohistochemistry was used to assess ERCC1 expression in pretreatment biopsy specimens from paraffin blocks. Clinical parameters, including smoking, alcohol consumption and betel nuts chewing, were obtained from the medical records.</p> <p>Results</p> <p>The 12-month progression-free survival (PFS) and 2-year overall survival (OS) rates of fifty-seven patients were 61.1% and 61.0%, respectively. Among these patients, thirty-one patients had low ERCC1 expression and forty-one patients responded to IC followed by CCRT. Univariate analyses showed that patients with low expression of ERCC1 had a significantly higher 12-month PFS rates (73.3% vs. 42.3%, p < 0.001) and 2-year OS (74.2 vs. 44.4%, p = 0.023) rates. Multivariate analysis showed that for patients who did not chew betel nuts and had low expression of ERCC1 were independent predictors for prolonged survival.</p> <p>Conclusions</p> <p>Our study suggest that a high expression of ERCC1 predict a poor response and survival to cisplatin-based IC followed by CCRT in patients with locally advanced unresectable HNSCC in betel nut chewing area.</p