The H2+_2^+ molecular ion: a solution

Combining the WKB expansion at large distances and Perturbation Theory at small distances it is constructed a compact uniform approximation for eigenfunctions. For lowest states 1s\si_{g} and 2p\si_{u} this approximation provides the relative accuracy $\lesssim 10^{-5}$ (5 s.d.) for any real $x$ in eigenfunctions and for total energy $E(R)$ it gives 10-11 s.d. for internuclear distances $R \in [0,50]$. Corrections to proposed approximations are evaluated. Separation constants and the oscillator strength for the transition 1s\si_{g} \rar 2p\si_{u} are calculated and compared with existing data.Comment: 16 pages, 4 figures, 6 tables, typos are corrected and small additions are inserted, to be published at JPB (fast track comm

LKR/SDH Plays Important Roles throughout the Tick Life Cycle Including a Long Starvation Period

BACKGROUND:Lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH) is a bifunctional enzyme catalyzing the first two steps of lysine catabolism in plants and mammals. However, to date, the properties of the lysine degradation pathway and biological functions of LKR/SDH have been very little described in arthropods such as ticks. METHODOLOGY/PRINCIPAL FINDINGS:We isolated and characterized the gene encoding lysine-ketoglutarate reductase (LKR, EC 1.5.1.8) and saccharopine dehydrogenase (SDH, EC 1.5.1.9) from a tick, Haemaphysalis longicornis, cDNA library that encodes a bifunctional polypeptide bearing domains similar to the plant and mammalian LKR/SDH enzymes. Expression of LKR/SDH was detected in all developmental stages, indicating an important role throughout the tick life cycle, including a long period of starvation after detachment from the host. The LKR/SDH mRNA transcripts were more abundant in unfed and starved ticks than in fed and engorged ticks, suggesting that tick LKR/SDH are important for the starved tick. Gene silencing of LKR/SDH by RNAi indicated that the tick LKR/SDH plays an integral role in the osmotic regulation of water balance and development of eggs in ovary of engorged females. CONCLUSIONS/SIGNIFICANCE:Transcription analysis and gene silencing of LKR/SDH indicated that tick LKR/SDH enzyme plays not only important roles in egg production, reproduction and development of the tick, but also in carbon, nitrogen and water balance, crucial physiological processes for the survival of ticks. This is the first report on the role of LKR/SDH in osmotic regulation in animals including vertebrate and arthropods

Determination of phenolic compounds in saussurea salicifolia (l.) DC by HPLC

Byly analyzovány aglykony flavonoidů obsažené v extraktu Saussurea salicifolia (L.) DC, získaného pomocí octanu etylnatého. Analýza byla provedena metodou HPLC přístrojem "Agilent" 1100 na sloupci stacionární fáze Alltech C18 ?m, s použitím detektoru UV254, rychlost toku mobilní fáze: 1 ml/min, mobilní fáze: acetonitril : voda : kyselina octová (36:65:1). Těmito analýzami bylo nalezeno jedenáct aglykonů flavonoidů. Kvantifikace separovaných složek byla provedena dle standardů. Bylo zjištěno, že Saussurea salicifolia z významných flavonoidních aglykonů obsahuje quercetin (28.62%) a kaempferol (3.01%).The flavonoid aglycone content of ethyl acetate fraction of Saussurea salicifolia (L.) DC was analysed by the HPLC ?Agilent? 1100 with Alltech C18 ?m column, UV254 detector, flow rate: 1 ml/min, mobile phase: acetonitrile: water:acetic acid (36:65:1). Eleven flavonoid aglycones in the ethyl acetate fraction of Saussurea salicifolia were detected by HPLC analysis. The quantification of each compound was done according to the peak area measurements which were reported in calibration curves of the corresponding standards. The result revealed that Saussurea salicifolia consists of flavonoid aglycones of quercetin (28.62%) and kaempferol (3.01%)

Anticancer activity of lignan from the aerial parts of saussurea salicifolia (l.) DC.

Nadzemní části Saussurea salicifolia (L.) DC byly analyzovány na obsah lignanů a flavonoidů po rozpuštění etanolového extraktu v chloroformu a n-butanolu. Vlastní identifikace fenolických sloučenin v chloroformové a n-butanolové frakce byly provedeny na zařízení Dionex HPLC-DAD s gradientovou elucí soustavou vodoa-metanol při 4 různý vlnových délkách (235 nm, 254 nm, 280 nm a 340 nm), s online použitím UV a LC-MS detekce. V chloroformové frakci převládal lignan s antirakovinnou aktivitou 9-OH-pinoresinol, kdežto v n-butanoloné frakci byly patrny hlavně hlavně flavonoidní glykosidy s protizánětlivými účinky jako quercetin-3-o-galactosid a apigenin-7-o-rhamnosid. Dodatečně, byl v n-butanoloné frakci nalezen také 9-OH-pinoresinol. Protirakovinné testy byly prováděny v lymfatických buňkách myší s leukemií L5178Y v koncentraci testované látky 10 ?g/ml. Surový etanolový extrakt S. salicifolia redukoval růst leukemických myší lymfatických buněk L5178Y až na 23.8%.Aerial parts of Saussurea salicifolia (L.) DC were studied for their lignan and flavonoids in solvent chloroform and n-butanol of ethanolic extract. Isolation and identification of phenolic compounds of the chloroform and n-butanol fractions were performed with Dionex HPLC-DAD system with water-methanol gradients in 4 different wave lengths (235 nm, 254 nm, 280 nm and 340 nm), using online UV and LC-MS as described previously. 9-OH-pinoresinol which is a lignan with anticancer activity was dominated in the chloroform fraction, whereas mainly flavonoid glycosides like quercetin-3-o-galactoside, apigenin-7-o-rhamnoside with anti-inflammatory effect were detected in the n-butanol fraction. Additionally, 9-OH-pinoresinol was also found in the n-butanol fraction. Anticancer tests were conducted in leukemia mouse lymphoma cells L5178Y at a concentration of 10 ?g/ml of test compound. Crude ethanol extract of S. salicifolia reduced the growth of leukemia mouse lymphoma cells L5178Y to 23.8%

Data from: Applying a dryland degradation framework for rangelands: the case of Mongolia

Livestock-caused rangeland degradation remains a major policy concern globally and the subject of widespread scientific study. This concern persists in part because it is difficult to isolate the effects of livestock from climate and other factors that influence ecosystem conditions. Further, degradation studies seldom use multiple plant and soil indicators linked to a clear definition of and ecologically-grounded framework for degradation assessment that distinguishes different levels of degradation. Here, we integrate two globally applicable rangeland degradation frameworks and apply them to a broad-scale empirical dataset for the country of Mongolia. We compare our assessment results with two other recent national rangeland degradation assessments in Mongolia to gauge consistency of findings across assessments and evaluate the utility of our framework. We measured livestock-use impacts across Mongolia’s major ecological zones: mountain and forest steppe, eastern steppe, steppe, and desert steppe. At 143 sites in 36 counties, we measured livestock-use and degradation indicators at increasing distances from livestock corrals in winter-grazed pastures. At each site, we measured multiple indicators linked to our degradation framework, including plant cover, standing biomass, palatability, species richness, forage quality, vegetation gaps and soil surface characteristics. Livestock use had no effect on soils, plant species richness or standing crop biomass in any ecological zone, but subtly affected plant cover and palatable plant abundance. Livestock effects were strongest in the steppe zone, moderate in the desert steppe and limited in the mountain/forest and eastern steppes. Our results aligned closely with those of two other recent country-wide assessments, suggesting that our framework may have widespread application. All three assessments found that very severe and irreversible degradation is rare in Mongolia (1-18% of land area), with most rangelands only slightly (33-53%) or moderately (25-40%) degraded. We conclude that very severe livestock-induced rangeland degradation is overstated in Mongolia. However, targeted rangeland restoration coupled with monitoring, adaptive management and stronger rangeland governance are needed to prevent further degradation where heavy grazing could cause irreversible change. Given the broad applicability of our degradation framework for Mongolia, we suggest it be tested for application in other temperate grasslands throughout Central Asia and North America