春季季风转换期间孟加拉湾的初级生产力

2010年中国科学院东北印度洋科学考察期间,对孟加拉湾水域初级生产力展开了研究.孟加拉湾表层水体的水温较高,盐度变化范围较大,且上层水体营养盐含量较低,在真光层底部营养盐浓度突然增加.表层叶绿素a浓度较低(＜0.1 mg/m3),叶绿素a最大值常出现在75 m水深处,上层水体浮游植物的生长受氮限制明显.表层潜在初级生产力低于0.2mgcm-3h-1,且初级生产速率在50-75 m出现最大值.水柱中初级生产力变化范围为199-367 mgCm-2d-1,高值出现在88°-89°(E)附近.浮游植物固碳的主要贡献者是微微型浮游生物(＜3 μm),其次是小型浮游生物(＞20 μm)和微型浮游生物(3-20 μm),但表层与75 m水深处固碳浮游植物的结构有一定差异.将孟加拉湾与阿拉伯海初级生产力进行对比,孟加拉湾水体初级生产力显著低于阿拉伯海,且初级生产力的影响因素有着显著的差异.     

The effect of ozagrel sodium on photochemical thrombosis in rat: therapeutic window and combined therapy with heparin sodium

The therapeutic efficacy of ozagrel sodium (ozagrel), alone and in combination with heparin, and its therapeutic time window were studied in a photochemically induced thrombotic cerebral infarction rat model. Cerebral artery thrombosis was induced by irradiating the brain with green light through intact skull using rose bengal as the photosensitizing dye. One set of animals was treated immediately after thrombosis with (1) vehicle, (2) 10 mg/kg ozagrel in saline, intravenously (i.v.), (3) 150 U/kg unfractioned heparin, subcutaneously (s.c.), or (4) ozagrel, i.v. plus heparin, s.c. Infarct volume was significantly smaller and edema was reduced in the ozagrel-treated groups compared to the vehicle-treated group; heparin did not convey additional benefit. In another set of animals, rats were given either vehicle or 10 mg/kg ozagrel in saline, i.v., 60 min or 120 min after induction of thrombosis. Ozagrel reduced infarct volume, but its effect diminished with delayed administration. The therapeutic window was determined to be less than 60 minutes after induction of thrombosis.     

Inhibition of vesicular glutamate storage and exocytotic release by Rose Bengal

It had been thought that quantal size in synaptic transmission is invariable. Evidence has been emerging, however, that quantal size can be varied under certain conditions. We present evidence that alteration in vesicular [(3)H]L-glutamate (Glu) content within the synaptosome (a pinched-off nerve ending preparation) leads to a change in the amount of exocytotically released [(3)H]Glu. We found that Rose Bengal, a polyhalogenated fluorescein derivative, is a quite potent membrane-permeant inhibitor (K(i) = 19 nM) of glutamate uptake into isolated synaptic vesicles. This vesicular Glu uptake inhibition was achieved largely without affecting H(+)-pump ATPase. We show that various degrees of reduction elicited by Rose Bengal in [(3)H]Glu in synaptic vesicles inside the synaptosome result in a corresponding decrease in the amount of [(3)H]Glu released in a depolarization- (induced by 4-aminopyridine) and Ca(2+)-dependent manner. In contrast, fluorescein, the halogen-free analog of Rose Bengal, which is devoid of inhibitory activity on vesicular [(3)H]Glu uptake, failed to change the amount of exocytotically released [(3)H]Glu. These observations suggest that glutamate synaptic transmission could be altered by pharmacological intervention of glutamate uptake into synaptic vesicles in the nerve terminal, a new mode of synaptic manipulation for glutamate transmission.     

Metabolism of geraniol in grape berry mesocarp of Vitis vinifera L. cv. Scheurebe: demonstration of stereoselective reduction, E/Z-isomerization, oxidation and glycosylation

The metabolism of deuterium labeled geraniol in grape mesocarp of Vitis vinifera L. cv. Scheurebe was studied by in vivo-feeding experiments. Stereoselective reduction to (S)-citronellol, E/Z-isomerization to nerol, oxidation to neral/geranial and glycosylation of the corresponding monoterpene alcohols could be demonstrated. Time course studies including the determination of conversion rates revealed that the activity of these secondary transformations of monoterpenes is dependent on the ripening stage and can be distinguished from the development of the primary monoterpene synthase activities by the sharp increase at the end of the ripening period. The stereoselective biosynthesis of the potent odorant cis-(2S,4R)-rose oxide from labeled geraniol in grape berry mesocarp is demonstrated as well. Since (S)-citronellol is the precursor of cis-(2S,4R)-rose oxide it can be concluded that especially the last part of the ripening period is important for the generation of this potent odorant. This finding confirms the conclusion that a higher concentration of flavor compounds could be established in the berries by leaving the fruit on the vine for extended periods.     

Evaluation of the European method for mapping lichen diversity (LDV) as an indicator of environmental stress in the Czech Republic

The European method for mapping lichen diversity (LDV) as an indicator of environmental stress/quality in the Czech Republic was evaluated to determine its applicability in this country. A modified Hawksworth & Rose qualitative scale for determining air pollution levels was used for comparative purposes. The study was undertaken in a partially forested and reasonably polluted region of the Bohemian Karst in central Bohemia during 2003. Measurements obtained by the LDV method yielded values in the range 18–65; measurements obtained by the modified Hawksworth & Rose method indicated zones 4–7, with a high correlation with the LDV results. The LDV method proved to be applicable in the region, but its implementation may be limited by the lack of suitable trees and specific landscape ecology.     

Apoptosis in tumour cells photosensitized with Rose Bengal acetate is induced by multiple organelle photodamage

Rose Bengal (RB) is a very efficient photosensitizer which undergoes inactivation of its photophysical and photochemical properties upon addition of a quencher group—i.e. acetate—to the xanthene rings. The resulting RB acetate (RB-Ac) derivative behaves as a fluorogenic substrate: it easily enters the cells where the native photoactive molecule is restored by esterase activities. It is known that the viability of RB-Ac-loaded cells is strongly reduced by light irradiation, attesting to the formation of intracellular RB. The aim of this study was to identify the organelles photodamaged by the intracellularly formed RB. RB-Ac preloaded rat C6 glioma cells and human HeLa cells were irradiated at 530 nm. Fluorescence confocal imaging and colocalization with specific dyes showed that the restored RB molecules redistribute dynamically through the cytoplasm, with the achievement of a dynamic equilibrium at 30 min after the administration, in the cell systems used; this accounted for a generalized damage to several organelles and cell structures (i.e. the endoplasmic reticulum, the Golgi apparatus, the mitochondria, and the cytoskeleton). The multiple organelle damage, furthermore, led preferentially to apoptosis as demonstrated by light and electron microscopy and by dual-fluorescence staining with FITC-labelled annexin V and propidium iodide.     

Mechanisms of Rose Bengal inhibition on SecA ATPase and ion channel activities

SecA is an essential protein possessing ATPase activity in bacterial protein translocation for which Rose Bengal (RB) is the first reported sub-micromolar inhibitor in ATPase activity and protein translocation. Here, we examined the mechanisms of inhibition on various forms of SecA ATPase by conventional enzymatic assays, and by monitoring the SecA-dependent channel activity in the semi-physiological system in cells. We build on the previous observation that SecA with liposomes form active protein-conducting channels in the oocytes. Such ion channel activity is enhanced by purified Escherichia coli SecYEG–SecDF·YajC liposome complexes. Inhibition by RB could be monitored, providing correlation of in vitro activity and intact cell functionality. In this work, we found the intrinsic SecA ATPase is inhibited by RB competitively at low ATP concentration, and non-competitively at high ATP concentrations while the translocation ATPase with precursors and SecYEG is inhibited non-competitively by RB. The Inhibition by RB on SecA channel activity in the oocytes with exogenous ATP-Mg²⁺, mimicking translocation ATPase activity, is also non-competitive. The non-competitive inhibition on channel activity has also been observed with SecA from other bacteria which otherwise would be difficult to examine without the cognate precursors and membranes.     

虎的日粮营养和表观消化率的测定

为了解动物园中圈养虎对日粮中各主要营养成分的摄入量及其表观消化率,于2004年12月对6只华南虎(Panthera tigris amoyensis)和1只孟加拉虎(P.t.tigris)日粮的营养成分进行了分析,并测定了其表观消化率。结果表明,尽管每只虎的日粮组成及其营养成分不尽相同,但是虎对粗蛋白、脂肪等主要营养成分和能量的表观消化率都很高,而且非常接近,分别为(97±0.7)%、(98±1.0)%和(97±1.3)%;对干物质及灰分的表观消化率差异较大,分别为86%~95%,36%~65%,估计与日粮中骨骼成分含量差异较大有关。其中成年虎对粗蛋白、脂肪、能量的每日摄入量分别为:(1 061.3±134.4)g,(251.3±63.3)g,(35 276.7±6 009.1)kJ。     

Ethylene and in vitro rooting of rose shoots

Effects of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), ethylene biosynthesis inhibitor, (CoCl₂), and inhibitor of ethylene binding to receptors, 1-methylcyclopropene (1-MCP), on ethylene production and rooting in shoot culture of Rosa hybrida L. cv. Alba meidiland were studied. Additionally, effect of ethylene removal by KMnO₄ and HgClO₄ on rooting was tested. ACC increased ethylene production and delayed root formation, decreased the number of roots per shoot and inhibited root growth. In contrast, inhibition of ethylene production by CoCl₂ accelerated root emergence, and increased the number of roots per shoot. Likewise, removing ethylene from the ambient atmosphere improved root emergence and, increased root number of per shoot and markedly inhibited root growth. Blocking the ethylene receptors by 1-MCP increased ethylene level in the ambient atmosphere and increased both emergence and root formation. Both ethylene biosynthesis and action are involved in the control of rooting. Ethylene concentration in glass jars was too high for root emergence and formation, but was appropriate for root growth. CoCl₂ or 1-MPC can be recommended for regulation of rooting in rose shoot culture, since both emergence and number of roots were improved but root growth was not inhibited.