Measurements of area and the (island) species-area relationship: new directions for an old pattern

Copyright © 2008 The Authors. Journal compilation.Copyright © 2008 Oikos.The species-area relationship is one of the strongest empirical generalizations in geographical ecology, yet controversy persists about some important questions concerning its causality and application. Here, using more accurate measures of island surface size for five different island systems, we show that increasing the accuracy of the estimation of area has negligible impact on the fit and form of the species–area relationship, even though our analyses included some of the most topographically diverse island groups in the world. In addition, we show that the inclusion of general measurements of environmental heterogeneity (in the form of the so-called choros model), can substantially improve the descriptive power of models of island species number. We suggest that quantification of other variables, apart from area, that are also critical for the establishment of biodiversity and at the same time have high explanatory power (such as island age, distance, productivity, energy, and environmental heterogeneity), is necessary if we are to build up a more predictive science of species richness variation across island systems

Pretraživanje tradicionalnih europskih ljekovitih biljaka na inhibiciju acetilkolinesteraze i butirilkolinesteraze

Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer’s disease (AD) to enhance central cholinergic transmission. On the other hand, butyrylcholinesterase (BuChE) inhibitors were reported to produce significant increases in brain extracellular AChE without triggering severe peripheral or central side-effects. In the present study, we selected twelve plants used in traditional European medicine to treat different central nervous system (CNS) disorders or to improve memory. Methanolic and hexane extracts of these plants were tested for the AChE and BuChE inhibitory activity using Ellman’s colorimetric method. The most potent AChE and BuChE inhibition was observed in the hexane extracts of the flowers of Arnica chamissonis Less. susb. foliosa and Ruta graveolens L. herb at a concentration of 400 μg mL1. However, methanolic extracts of the flowers of Arnica chamissonis Less. susb. foliosa and the Hypericum perforatum L. herb demonstrated at the same concentration, selective inhibition only against AChE but not against BuChE. The other extracts did not show any significant AChE or BuChE inhibitory activity. Our results show that further investigations of the extracts of arnica, rue and St. John’s Wort are needed to identify the compounds responsible for the AChE and BuChE inhibitory activityInhibitori acetilkolinesteraze (AChE) povećavaju kolinergičku transmisiju u mozgu, pa se koriste za simptomatsko liječenje Alzheimerove bolesti (AD). S druge strane, inhibitori butirilkolinesteraze (BuChE) značajno povećavaju ekstracelularnu količinu AChE u mozgu, a da pri tome ne uzrokuju snažne nuspojave ni u središnjem ni i perifernom živčanom sustavu. Galantamin, jedan od odobrenih AChE inhibitora, alkaloid iz lukovica narcisa, pokazuje da su biljke značajni izvor novih potencijalnih AChE- i BuChE- inhibitora. U ovom radu, ispitivali smo učinak dvanaest biljaka koje se koriste u tradicionalnoj europskoj medicini na različite poremećaje središnjeg živčanog sustava i na poboljšanje pamćenja. Pomoću Ellmanove kolorimetrijske metode praćen je inhibitorni učinak metanolnih i heksanskih ekstrakata tih biljaka na AChE i BuChE. Najjači inhibitorni učinak pokazali su heksanski ekstrakti cvjetova Arnica chamissonis Less. susb. foliosa i nadzemnih dijelova Ruta graveolens L. u koncentraciji od 400 μg mL1. Međutim, metanolni ekstrakti cvjetova Arnica chamissonis Less. susb. foliosa i nadzemnih dijelova Hypericum perforatum L. u istim koncentracijama pokazuju selektivnu inhibiciju samo na AChE. Ostali ekstrakti bili su nedjelotvorni. Rezultati ukazuju na potrebu daljnjih ispitivanja ekstrakata arnike, rute i gospine trave da se utvrdi koji su sastojci ekstrakata odgovorni za inhibiciju AChE i BuChE

Protective effects of solvent fractions of Mentha spicata (L.) leaves evaluated on 4-nitroquinoline-1-oxide induced chromosome damage and apoptosis in mouse bone marrow cells

Spearmint leaves (Mentha spicata L.) contain high levels of antioxidants that are known to protect against both exogenous and endogenous DNA damage. In this study, the protective effects of the hexane fraction (HF), chloroform fraction (CF) and ethyl acetate fraction (EAF) in an ethanol extract from M. spicata were evaluated against 4-nitroquinoline-1-oxide (4-NQO) induced chromosome damage and apoptosis in bone marrow cells of Swiss albino mice. Two (EAF; 80 and 160 mg/ kg body weight - bw) or three (HF and CF; 80, 160 and 320 mg/ kg bw) doses of solvent fractions or vehicle control (25% DMSO in water) were administered orally for five consecutive days. Upon the sixth day, 4-NQO was injected intraperitoneally. The animals were killed the following day. Other control groups were comprised of animals treated with either the vehicle control or the various doses of solvent fractions, but with no 4-NQO treatment. 4-NQO induced micro-nucleated polychromatic erythrocytes (MnPCEs) in all the test groups. However, pre-treatment of animals with the solvent fractions significantly reduced the 4-NQO-induced MnPCEs as well as the percentage of apoptotic cells. The reduction of both MnPCE and apoptosis was more evident following the pre-treatment of animals with 160 mg/kg bw EAF

Cytotoxic activity of proteins isolated from extracts of Corydalis cava tubers in human cervical carcinoma HeLa cells

<p>Abstract</p> <p>Background</p> <p><it>Corydalis cava </it>Schweigg. & Koerte, the plant of numerous pharmacological activities, together with the studied earlier by our group <it>Chelidonium majus </it>L. (Greater Celandine), belong to the family <it>Papaveraceae</it>. The plant grows in Central and South Europe and produces the sizeable subterraneous tubers, empty inside, which are extremely resistant to various pathogen attacks. The <it>Corydalis sp. </it>tubers are a rich source of many biologically active substances, with the extensive use in European and Asian folk medicine. They have analgetic, sedating, narcotic, anti-inflammatory, anti-allergic and anti-tumour activities. On the other hand, there is no information about possible biological activities of proteins contained in <it>Corydalis cava </it>tubers.</p> <p>Methods</p> <p>Nucleolytic proteins were isolated from the tubers of <it>C. cava </it>by separation on a heparin column and tested for DNase activity. Protein fractions showing nucleolytic activity were tested for cytotoxic activity in human cervical carcinoma HeLa cells. Cultures of HeLa cells were conducted in the presence of three protein concentrations: 42, 83 and 167 ng/ml during 48 h. Viability of cell cultures was appraised using XTT colorimetric test. Protein fractions were separated and protein bands were excised and sent for identification by mass spectrometry (LC-ESI-MS/MS).</p> <p>Results</p> <p>The studied protein fractions showed an inhibiting effect on mitochondrial activity of HeLa cells, depending on the administered dose of proteins. The most pronounced effect was obtained with the highest concentration of the protein (167 ng/ml) - 43.45 ± 3% mitochondrial activity of HeLa cells were inhibited. Mass spectrometry results for the proteins of applied fractions showed that they contained plant defense- and pathogenesis-related (PR) proteins.</p> <p>Conclusions</p> <p>The cytotoxic effect of studied proteins toward HeLa cell line cells has been evident and dependent on increasing dose of the protein. The present study, most probably, represents the first investigations on the effect of purified PR proteins from tuber extracts of a pharmacologically active plant on cell lines.</p