琵琶湖西岸流域におけるタブノキ個体群の分布と地域植生

本研究は,滋賀県琵琶湖西岸(湖西)流域の安曇川,鴨川および石田川を対象に,タブノキ個体群の分布を明らかにするとともに,滋賀県におけるタブノキ個体群の植生環境を解析することを目的としている。2006年8月から2007年2月までの期間に滋賀県全域を踏査し,タブノキ個体群の位置をGPSによって記録した。その後,湖西の三河川を対象に,2007年6月から2008年2月の期間に現地調査を実施し,タブノキおよびタブノキ個体群の分布図をGISによって作成した。タブノキ個体群の半径1kmエリア(GIS図面積概算3.13 km^2)の植生比率から,タブノキ林がきわめて孤立化していることが明らかにされた。現地調査から,成熟したタブノキ(胸高直径:≥20 cm)は安曇川の河畔林で13個体,鴨川で47個体,石田川で8個体が確認された。河畔林以外には,安曇川流域の社寺境内にタブノキの大径木(DBH≥100 cm)が確認された。現地調査とGISによる植生解析から,タブノキが地域植生や文化と深く関わっていることが明らかにされたが,上記三河川の河畔に生育するタブノキ個体群のうち,平均すると78.9±7.8%の個体群がモウソウチク林やマダケ林など,竹林の侵入を受けていた。以上のことから,竹林の適正管理によって,琵琶湖を特徴づける固有の地域植生として,タブノキ個体群およびタブノキ林の保全をはかることが重要といえる。This study seeks to clarify the spatial distribution of the Persea thunbergii population and their vegetation habitat, at the three western river basins of Lake Biwa, in Shiga Prefecture, Central Japan. We recorded the position of mature P. thunbergii trees (diameter at breast height≥20 cm) with GPS (Geographic positioning system) in Shiga Prefecture between August 2006 and February 2007, and also investigated the number, size and habitats of mature P. thunbergii trees along the Ado River, the Kamo River and the Ishida River between June 2007 and February 2008. Ratios of vegetation of the surrounding 3.13 km^2 area for each of the main P. thunbergii stands were also analyzed from actual vegetation map of Japan Integrated Biodiversity Information System data using GIS (Geographic information system). Mature P. thunbergii trees were distributed in the riparian forests within a 5 km distance from Lake Biwa along the Ado River, the Kamo River and the Ishida River: Mature P. thunbergii trees in these three river basins totaled 13, 47 and 8 in number, respectively. We also found large P. thunbergii trees (DBH≥100 cm) in sacred shrines in the basin of the Ado River. Bamboo invaded 78.9±7.8 % of P. thunbergii population in riparian forests. These results suggest that the habitats of P. hunbergii populations are isolated and that the expansion of bamboo stands decrease biological diversity of this area. The management of bamboo stands is needed for the conservation of P. thunbergii population, which characterize the vegetation of Lake Biwa area

Comparative genomic analyses identify common molecular pathways modulated upon exposure to low doses of arsenic and cadmium

<p>Abstract</p> <p>Background</p> <p>Exposure to the toxic metals arsenic and cadmium is associated with detrimental health effects including cancers of various organs. While arsenic and cadmium are well known to cause adverse health effects at high doses, the molecular impact resulting from exposure to environmentally relevant doses of these metals remains largely unexplored.</p> <p>Results</p> <p>In this study, we examined the effects of <it>in vitro </it>exposure to either arsenic or cadmium in human TK6 lymphoblastoid cells using genomics and systems level pathway mapping approaches. A total of 167 genes with differential expression were identified following exposure to either metal with surprisingly no overlap between the two. Real-time PCR was used to confirm target gene expression changes. The gene sets were overlaid onto protein-protein interaction maps to identify metal-induced transcriptional networks. Interestingly, both metal-induced networks were significantly enriched for proteins involved in common biological processes such as tumorigenesis, inflammation, and cell signaling. These findings were further supported by gene set enrichment analysis.</p> <p>Conclusions</p> <p>This study is the first to compare the transcriptional responses induced by low dose exposure to cadmium and arsenic in human lymphoblastoid cells. These results highlight that even at low levels of exposure both metals can dramatically influence the expression of important cellular pathways.</p

Sphingolipids as critical players in retinal physiology and pathology

Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established toparticipate in numerousprocesses, suchas neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is therefore crucial in the onset and progression of retinal diseases. This review examines the involvement of sphingolipids in retinal physiology and diseases. Ceramide (Cer) has emerged as a common mediator of inflammation and death of neuronal and retinal pigment epithelium cells in animal models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. Sphingosine- 1-phosphate (S1P) has opposite roles, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1- phosphate may also contribute to uveitis. Notably, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), preserves neuronal viability and retinal function. These findings underscore the relevance of alterations in the sphingolipid metabolic network in the etiology of multiple retinopathies and highlight the potential of modulating their metabolism for the design of novel therapeutic approaches.Fil: Simon, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Basu, Sandip K.. University of Tennessee; Estados UnidosFil: Qaladize, Bano. University of Tennessee; Estados UnidosFil: Grambergs, Richards. University of Tennessee; Estados UnidosFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Mandal, Nawajes .A.. University of Tennessee; Estados Unido