Structures and functions of carotenoids bound to reaction centers from purple photosynthetic bacteria

The photoprotective function of 15,15'-cis-carotenoids bound to the photosynthetic reaction centers (RCs) of purple bacteria has been studied using carotenoids reconstituted into carotenoidless RCs from Rhodobacter sphaeroides strain R26.1. The triplet-energy level of the carotenoid has been proposed to affect the quenching of the triplet state of special-pair bacteriochlorophyll (P). This was investigated using microsecond flash photolysis to detect the carotenoid triplets as a function of the number of conjugated double bonds, n. The carotenoid triplet signals were extracted by using singular-value decomposition (SVD) of the huge matrices data, and were confirmed for those having n = 8 to 11. This interpretation assumes that the reconstituted carotenoids occupy the same binding site in the RC. We have been able to confirm this assumption using X-ray crystallography to determine the structures of carotenoidless, wild-type carotenoid-containing, and 3,4-dihydro-spheroidene-reconstituted RCs. The X-ray study also emphasized the importance of the methoxy group of the carotenoids for binding to the RCs. Electroabsorption (Stark) spectroscopy was used to investigate the effect of the carotenoid on the electrostatic field around P. This electrostatic field changed by 10 % in the presence of the carotenoid

Automated System for Direct Production of [N-13]Ammonia with a Circulating Water-Hydrogen Target

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Effects of ethyl-esterization, chain-lengths, unsaturation degrees, and hyperthermia on carcinostatic effect of omega-hydroxylated fatty acids

Aim: To evaluate promotive effect of hyperthermia on the carcinostatic activity of synthesized omega-hydroxy fatty acids (wHFAs) and their ethylesters agaist Ehrlich ascites tumor (EAT) cells. Methods: EAT cells were cultured with either wHFAs or their ethylester derivatives in a water bath at either 37 °C or 42 °C for 30 min, followed by incubation in a CO2 incubator for 20 or 72 h. Mitochondrial dehydrogenase-based WST-1 assay and trypan blue dye exclusion assay were then conducted after incubation. Morphological changes were observed by scanning electron microscopy (SEM). Results: Omega-HFA having a saturated 16-carbon straight-chain (wH16:0) was the most carcinostatic (at 37 °C – viability level: 60.0%; at 42 °C – 49.6% (WST-1)) among saturated and unsaturated wHFAs with 12, 15 or 16 carbon atoms, when administrated to EAT cells at 100 µM for 20 h. Carcinostatic activity was markedly enhanced by ethyl-esterization of saturated fatty acids, such as wH16:0 (at 37 °C – 42.3%; at 42 °C – 11.2% , ibid) and wH15:0 (at 37 °C – 74.6%; at 42 °C – 25.3% , ibid), and their unsaturated counterparts were extremely effective only in combination with hyperthermia. Prolongation of the incubation period to 72 h at the same concentration increased appreciably their carcinostatic effect (wH16:0 ethylesther: 1.3%; wH15:0 ethylesther: 8.0%). These values were also supported by dye exclusion assay. The carcinostatic activity enhanced more markedly by hyperthermia (1.2%; 2.1%, ibid). SEM shows that wH16:0 ethylester-exposed EAT cells underwent extensive injury, such as deformation of cell structure or disappearance of microvilli. Conclusions: wH16:0 ethylester possesses high carcinostatic activity in vitro in combination with hyperthermia and may be utilized as potent anticancer therapeutic agent.Цель: проанализировать усиливающий эффект гипертермии на канцеростатическую активность синтезированных омегагидроксилированных жирных кислот (HFAs) и их этиловых эфиров по отноению к клеткам асцитной опухоли рлиха (EAT). Методы: клетки EAT инкубировали с HFAs или их этилэфирными производными на водной ане при 37 ° или 42 ° в течение 30 мин с дальнейим культивированием в 2 инкубаторе на протяжении 20 или 72 ч, после чего анализировали жизнеспособность клеток методами анализа WST-1, основанного на активности митохондриальных дегидрогеназ, и по включению трипанового синего. Морфологические изменения клеток определяли с использованием сканирующей электронной микроскопии. Результаты: при культивации клеток EAT в присутствии 100 M соединений в течение 20 ч омега-HFA с насыщенной 16-углеродной прямой цепью (H16:0) проявляли наиболее выраженный канцеростатический эффект (при 37 ° уровень жизнеспосоности составил 60,0%; при 42 ° 49,6% (WST-1)) по сравнению с таковым насыщенных и ненасыщенных HFAs, содержащих 12, 15 или 16 атомов углерода. анцеростатическая активность значительно возрастала при этилэтерификации насыщенных жирных кислот, таких как H16:0 (при 37 ° 42,3%; при 42 ° 11,2%, ibid) и H15:0 (при 37 ° 74,6%; при 42 ° 25,3% , ibid), в то время как производные ненасыщенных кислот были высокоэффективны только в комбинации с гипертермией. Увеличение периода инкубации клеток до 72 ч при той же концентрации веществ приводило к значительному увеличению их канцеростатического действия (этиловый эфир H16:0 1,3%; этиловый эфир H15:0 ethylesther 8,0%), подтвержденного данными окраски трипановым синим. рименение гипертермии также усиливало канцеростатическое действие соединений (1,2%; 2,1%, ibid). Результаты исследования методом SEM показали, что клетки EAT, инкубированные с этиловым эфиром H16:0, разруаются с нарушением клеточной структуры и исчезновением микроволокон. Выводы: в комбинации с гипертермией этиловый эфир H16:0 про ет высокую канцеростатическую активность in vitro, что говорит о возможности применения соединения в терапии опухолевых заболеваний

Measurement of the cosmic-ray antiproton spectrum at solar minimum with a long-duration balloon flight over Antarctica

The energy spectrum of cosmic-ray antiprotons from 0.17 to 3.5 GeV has been measured using 7886 antiprotons detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary antiproton calculations. Cosmologically primary antiprotons have been investigated by comparing measured and calculated antiproton spectra. BESS-Polar II data show no evidence of primary antiprotons from evaporation of primordial black holes.Comment: 4 pages, 4 figures, submitted to Physical Review Letter

The flail mitral valve: Echocardiographic findings by precordial and transesophageal imaging and doppler color flow mapping

AbstractTo determine the echocardiographic and Doppler characteristics of mitral regurgitation associated with a flail mitral valve, precordial and transesophageal echocardiography with pulsed wave and Doppler color flow mapping was performed in 17 patients with a flail mitral valve leaflet due to ruptured chordae tendineae (Group I) and 22 patients with moderate or severe mitral regurgitation due to other causes (Group II). Echocardiograms were performed before or during cardiac surgery; cardiac catheterization was also performed in 28 patients (72%). Mitral valve disease was confirmed at cardiac surgery in all patients.By echocardiography, the presence of a flail mitral valve leaflet was defined by the presence of abnormal mitral leaflet ccaptation or ruptured chordae. Using these criteria, transesophageal imaging showed a trend toward greater sensitivity and specificity than precordial imaging in the diagnosis of flail mitral valve leaflet. By Doppler color flow mapping, a flail mitral valve leaflet was also characterized by an eccentric, peripheral, circular mitral regurgitant jet that closely adhered to the walls of the left atrium. The direction of flow of the eccentric jet in the left atrium distinguished a flail anterior from a flail posterior leaflet. By transesophageal echocardiography with Doppler color flow mapping, the ratio of mitral regurgitant jet arc length to radius of curvature was significantly higher in Group I than Group II patients (5.0 ± 2.3 versus 0.7 ± 0.6, p < 0.001); all of the Group I patients and none of the Group II patients had a ratio >2.5.Thus, transesophageal imaging with Doppler color flow mapping of mitral regurgitation is complementary to precordial echocardiography in the diagnosis and localization of flail mitral valve leaflet due to ruptured chordae tendineae

Production of [15O]CO2 by the 15N(p,n)15O Reaction

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