THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY

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Growth and survival of Halimione portulacoides stem cuttings in heavy metal contaminated soils

The halophytic shrub Halimione portulacoides demonstrates a high tolerance to heavy metal contamination and a capacity for accumulating metals within its tissues. On the Iberian Peninsula, this species has colonized habitats with high levels of metal pollution. The aim of this study is to analyze the response of H. portulacoides stem cuttings to this pollution. Growth, photosynthesis and metal uptake were examined in H. portulacoides through an experiment in which stem cuttings were replanted in metal-contaminated soil. This condition decreased growth and lowered both photosynthetic rate and stomatal conductance. Reduced photosynthetic performance was largely due to the reduced concentration of photosynthetic pigments. Despite these responses, there was some important evidence suggesting the phytoremediatory potential of Halimione stem cuttings. The results of our study indicate that this salt-marsh shrub may represent a biotool of value in the restoration of polluted areas.     

准噶尔盆地渐新世安集海河组类胡萝卜素的发现及古环境意义

作为一类天然色素,类胡萝卜素在自然界中广泛分布。在沉积记录中,类胡萝卜素多以结构稳定的衍生物形式赋存。部分具有芳香基的结构的组分与光合硫细菌的活动有关,因而这些特定生物来源的组分为恢复古水体环境提供了一个重要的依据。通常光合硫细菌多生存在缺氧且富硫的透光层,地质记录中的芳香基类胡萝卜素往往反映了古水体中发育硫化透光带。类胡萝卜素衍生物的组合差异与硫细菌群落的相关性为古水深、微生物优势群落以及营养元素利用与循环等方面的研究提供了线索和证据。因此,类胡萝卜素衍生物在油源对比、生命起源、生物灭绝事件以及大洋缺氧事件等诸多地质过程的研究中起到至关重要的指示作用。本文主要通过探讨准噶尔盆地南缘安集海河组有机质中的类胡萝卜素的结构,分析其成因类型和特定来源,阐释古环境与古气候演化,进而恢复与重建渐新世时期准噶尔盆地南缘古湖泊的水体条件与微生物群落。从结果来看,准噶尔盆地安集海组中发育绿硫细菌来源的绿硫菌烷、异海绵烷等芳香基类胡萝卜素,可以推测这一时期湖泊水体存在硫化透光带现象;同时以叶黄素为来源的叶黄烷指示了蓝细菌是古湖泊中生物群落的重要组成部分。古湖泊发育硫化透光带往往与水体分层有关,而准噶尔盆...     

一株分离自北极海水红球菌(Rhodococcus sp.)B7740的生长条件及其粗类胡萝卜素提取方法的优化

红球菌(Rhodococcus sp.)B7740分离自北冰洋海水样品,前期实验表明其能产生大量黄色素,但是该菌生物量很低。本实验通过碳源、氮源、培养温度、发酵液起始pH值、菌种接种量等单因素和正交实验优化了该菌株的培养条件,在此基础上,通过对提取剂种类及pH、提取时间、料液比等的研究,优化了色素的提取条件。实验结果表明,1L陈海水中,添加5g酵母粉,5g葡萄糖,3g乳糖,7g牛肉膏;起始pH7,培养温度25℃,菌种接种量1.0%,160r/min摇床培养7d时,生物量从6.1mg/mL上升到23.08mg/mL,提高了278.4%。以上述培养条件下得到的干菌体为材料,采用pH7的无水乙醇,当料液比1:30,浸提温度75℃,浸提1h重复提取2次时,色素含量为1160.625μg/g干菌体。对色素的分析表明,该色素为类胡萝卜素,实验结果为进一步研究极地微生物红球菌(Rhodococcus sp.)B7740产类胡萝卜素的提取工艺提供了基础。     

饲料中添加虾青素对血鹦鹉皮肤类胡萝卜素含量和体色三刺激值的影响

为探讨投喂增色剂对鱼类增色效果的定量评价方法,分别用添加0、30、100、300、500、700、900 mg/kg虾青素的饲料饲喂血鹦鹉60 d,测定血鹦鹉皮肤中的总类胡萝卜素含量和鱼体体色的三刺激值。结果显示,血鹦鹉皮肤总类胡萝卜素含量随着虾青素添加量的增加而升高,而三刺激值X、Y、Z则逐渐减小。总类胡萝卜素含量300～900 mg/kg各组显著高于对照组(P<0.05),500、700和900 mg/kg组显著高于0、30、100 mg/kg组(P<0.05),而500、700和900 mg/kg各组间差异不显著(P>0.05)。总类胡萝卜素含量与三刺激值间的相关系数分别为-0.966、-0.932、-0.981,均达到极显著水平(P<0.01)。可见,在饲料中添加虾青素可明显提高血鹦鹉皮肤类胡萝卜素含量,改善血鹦鹉体色,血鹦鹉体色的三刺激值与皮肤总类胡萝卜素含量有极高的相关性,可用测色色差计测定血鹦鹉的三刺激值,并以此来推算鱼体皮肤总类胡萝卜素含量,定量评价血鹦鹉的体色。     

Assessment of leaf carotenoids content with a new carotenoid index: Development and validation on experimental and model data

Leaf carotenoids content (LCar) is an important indicator of plant physiological status. Accurate estimation of LCar provides valuable insight into early detection of stress in vegetation. With spectroscopy techniques, a semi-empirical approach based on spectral indices was extensively used for carotenoids content estimation. However, established spectral indices for carotenoids that generally rely on limited measured data, might lack predictive accuracy for carotenoids estimation in various species and at different growth stages. In this study, we propose a new carotenoid index (CARI) for LCar assessment based on a large synthetic dataset simulated from the leaf radiative transfer model PROSPECT-5, and evaluate its capability with both simulated data from PROSPECT-5 and 4SAIL and extensive experimental datasets: the ANGERS dataset and experimental data acquired in field experiments in China in 2004. Results show that CARI was the index most linearly correlated with carotenoids content at the leaf level using a synthetic dataset (R² = 0.943, RMSE = 1.196 μg/cm²), compared with published spectral indices. Cross-validation results with CARI using ANGERS data achieved quite an accurate estimation (R² = 0.545, RMSE = 3.413 μg/cm²), though the RBRI performed as the best index (R² = 0.727, RMSE = 2.640 μg/cm²). CARI also showed good accuracy (R² = 0.639, RMSE = 1.520 μg/cm²) for LCar assessment with leaf level field survey data, though PRI performed better (R² = 0.710, RMSE = 1.369 μg/cm²). Whereas RBRI, PRI and other assessed spectral indices showed a good performance for a given dataset, overall their estimation accuracy was not consistent across all datasets used in this study. Conversely CARI was more robust showing good results in all datasets. Further assessment of LCar with simulated and measured canopy reflectance data indicated that CARI might not be very sensitive to LCar changes at low leaf area index (LAI) value, and in these conditions soil moisture influenced the LCar retrieval accuracy.     

Enhanced Carotenoid Production by a Mutant of the Marine Yeast Rhodotorula sp. hidai

1 Introduction In recent years, carotenoids have received increasing attention as they have extensive use in medicine, cosmetic, chemistry, food industry and feed industry. In industry, carotenoid and astaxanthin can be used as the additives of food or feeds. Carotenoids can also serve as the precursor of vitamin A in mammals. In recent years, many types of carotenoid have aroused extensive interest because of their many beneficial effects on human health. For in-stance, lycopene and astaxant…     

Ancient Microorganisms and Carotenoids Preserved in Fluid Inclusions in Halite from Chaka Salt Lake,Western China: Evidence from Micro-observation and in situ Raman Spectroscopy

Trapped ancient microorganisms in halite fluid inclusions are of special interest to the understanding of biology and ecology in salt lake systems.With the integration of petrologic,microthermometric,and Raman spectroscopic analyses,this study utilizes fluid inclusions from Chaka Salt Lake,eastern Qaidam Basin,NW China,to assess the possibility of microorganism-trapping by fluid inclusions.Here,we report that the solid phase of some primary fluid inclusions contains carotenoids,which is interpreted as evidence of Dunaliella algae,and that the coexisting liquid phase comprises SO_4~(2-).The homogenization temperatures of single-phase primary fluid inclusions indicate that the precipitation temperature of the Holocene halite in Chaka Salt Lake ranges from 13.5°C to 36.4°C.This suggests that fluid inclusions in halite are a good medium for trapping and preserving ancient microorganisms and organic matter in salt lakes,and that Raman spectroscopy has good potential to identify halophilic archaea.     

Enhanced carotenoid production by a mutant of the marine yeast Rhodotorula sp. hidai

After a serial of UV, EMS and NTG mutagenesis, a mutant named MM of the red marine yeast strain Rhodotorula sp. hidai was obtained. The mutant MM could produce 603.93 μg g⁻¹ of carotenoid within 5 days in the medium containing 4.0 g sucrose, 1.5 g yeast extract, 0.1 g MgSO₄, and 100 mL of sea water, with pH 6.0 and at 30 °C, while only 213.18 μg g⁻¹ of carotenoid was produced by the wild type under the same conditions.     

Preliminary study on plasma membrane fluidity of Psychrophilic Yeast Rhodotorula sp.NJ298 in low temperature

The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature. Plasma membrane proteins, fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp. NJ298 were investigated at -3 ℃, 0 ℃ and 8 ℃. The results showed that plasma membrane protein content was greater at -3 ℃ than that at 8 ℃, and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis; GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids (C18∶ 1 and C18∶ 2) and shorter chain saturated fatty acid (C10∶ 0) increased along with the decrease of the culture temperature from 8 ℃ to -3 ℃; HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane, percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at -3 ℃. However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at -3 ℃, 0 ℃ and 8 ℃. Hence these changes in plasma membrane's characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature.