Morphological and phylogenetic analysis of a Gymnodinium-like species from the Chinese Coast

A Gymnodinium-like species was studied with light microscopy (LM) and scanning electron microscopy (SEM). Also, the internal transcribed spacers (containing 5.8S rDNA) and large ribosomal subunit DNA (D1-D2) sequences were obtained by PCR amplification, and then sequenced to explore the relationships within our isolate, Gymnodinium and other Gymnodinium-like species, including Karenia, Gyrodinium, Karlodinium and Symbiodinium. The LM observation showed that the species was characterized by moving in a levorotatory direction, visible hypocone, epicone and transverse groove, all of which are typical for Gymnodinium. In addition, two flagella could be found under SEM. The phylogenetic analysis revealed that the isolate grouped with Symbiodium, rather than other relevant dinoflagellates. All results showed our isolate belongs to Symbiodium. The strain was isolated from a red tide water sample, denoting that Symbiodium may be causative species for algal bloom.

几种赤潮微藻的形态和系统进化分析及荧光原位杂交检测

赤潮也称红潮，通常是指由于一些海洋浮游生物在水体中过度繁殖或聚集而使海水变色的现象。赤潮特别是有害赤潮造成了严重的生态环境问题，给水产养殖业和滨海旅游业造成了巨大损失，并可直接危害人类健康。研究赤潮，进而预防和控制赤潮，首先要对引发赤潮的生物种类进行准确鉴定并对自然水域的赤潮生物进行监控，并建立赤潮藻的快速鉴定与检测方法。本文分别对几株赤潮微藻进行了形态和系统进化分析，并探讨了荧光原位杂交在赤潮检测中的应用。 分别对5株分离自中国沿海不同水域的中肋骨条藻[Skeletonema costatum (Greville) Cleve]类似种 (SK-BH、SK-FQ、 SK-HH、SK-DH和SK-XM) 进行光镜和扫描电镜观察，并PCR扩增了转录内间隔区 (含5.8S rDNA)(ITS) 和核糖体大亚基 (D1-D2)区 (LSU)，获得的序列与其它已报道的骨条藻的同源序列进行了进化分析，以探讨５株骨条藻与已报道的骨条藻之间的进化关系。5株骨条藻在形态上各不相同，其中，只有1株 (SK-XM)被鉴定为中肋骨条藻，而其余4株皆与已报道的骨条藻的形态学特征不符。ITS树和LSU树具有不同的拓扑结构，并表明5株骨条藻至少分属3个不同的种。遗传距离分析提示了在地理距离上靠近的种，在进化上也可能靠近。此外，还可以观察到这5株藻之间的细微的形态学“进化”关系。所有结果表明了中国沿海骨条藻属种的多样性。 对1株分离自赤潮水域的裸甲藻 (Gymnodinium)类似种进行了形态学分析，并探讨了该藻与裸甲藻、凯伦藻(Karena)、旋沟藻(Gyrodinium)、下沟藻(Karlodinium)和共生甲藻(Symbiodinium)的进化关系。光镜观察表明该藻具有裸甲藻的一些典型的形态学特征，而我们没能获得细胞形态保存完好的电镜样品；进化分析初步鉴定该藻为一种共生甲藻。 获得了赤潮异湾藻[Heterosigma akashiwo (Hada) Hada]的LSU和ITS序列，设计了以胞质rRNA和胞核rDNA为靶序列的特异性探针，建立了赤潮异湾藻的全细胞和细胞核荧光原位杂交技术，对探针的特异性进行了验证，并考察了杂交信号和检测率在整个细胞周期的变化情况。探针能分别使整个细胞和细胞核呈现明亮的绿色荧光。探针是特异性的，不与其它受试藻进行交叉反应。杂交信号在整个细胞周期内变化不明显，且检测率为70%–80%。整个检测过程不到1 ｈ，能实现赤潮异湾藻的快速、准确、特异和半定量检测。 获得了海洋原甲藻(Prorocentrum micans Ehrenberg)的LSU和ITS序列，设计了以胞质rRNA为靶序列的特异性探针，建立了海洋原甲藻的全细胞荧光原位杂交技术，并对探针的特异性进行了验证。探针能使整个细胞呈现强烈的绿色荧光。探针不与其它受试藻种进行交叉反应，表明是特异性的。

化感作用对东海赤潮演替的影响

本论文通过2007年科学院创新项目KC2007-3航次现场调查和实验室微藻培养实验，研究了多胺对几种赤潮藻生长的影响，不同赤潮水体对几种赤潮藻生长的影响，硅藻赤潮消亡后海水几种溶解有机物的空间分布和时间变化及其与赤潮演替的关系，对实验室和现场观察到的现象进行了深入分析，得到了以下结论： 较低浓度的多胺对东海原甲藻和塔玛亚历山大藻等甲藻的促进作用要高于对中肋骨条藻的促进作用。多胺可能在硅藻赤潮向甲藻赤潮的演替中起了一定推进作用。 东海赤潮演替过程中典型的赤潮水体滤液对培养藻种生长的抑制或促进作用与现场演替过程相契合，化感物质是硅藻赤潮演替的影响因素之一。 东海硅藻赤潮消亡后的海水有较强的类蛋白荧光，主要荧光峰是类酪氨酸B峰。在赤潮消亡主要海区FIB/FIs较大，这表明类蛋白溶解有机物主要是由赤潮藻破碎分解产生的类酪氨酸。S峰、A峰和C峰三者之间互相呈较好的正相关，且3者的荧光强度与盐度都呈显著的线性负相关，其分布均呈现出近岸高远岸低的特点，这表明江浙沿岸水的输入是其共同的重要来源。 单糖、多糖、总糖和DOC与真光层生物活动密切相关。局部高值是之前赤潮高发的藻类产生的。 B峰强度与叶绿素a之间存在一定的负相关，类酪氨酸可能在pico-flagellates暴发过程中作为营养源或生长刺激物。

Phytoplankton distributions and their relationship with the environment in the Changjiang Estuary, China

This study was carried out in the Changjiang Estuary from 19 to 26 May 2003. Based on the data collected from 29 stations, including two anchor stations, phytoplankton taxonomic composition, abundance, diurnal variability and spatial distribution were examined. Eighty-seven species, including 54 species of diatoms and 16 red tide causative species, were identified. Average diversity index (H') and evenness (J) values were 1.04 and 0.40, respectively. A bloom in abundance of certain phytoplankton species, especially Prorocentrum dentatum and Skeletoneina costatum, was thought to be the cause of the low diversity index and evenness values. Total phytoplankton abundance averaged 6.75 x 10(5) cells 1(-1), and was much higher than previous investigation carried out in the same month in 1986. Abundance increased seaward showing a distinct spatial difference, and the dominant species varied with salinity. Correlation between phosphorus and abundance further supported the former conclusion that phosphorus is the controlling factor in phytoplankton growth in the Changjiang Estuary where light is not limiting. Based on the relationship between DO, pH and abundance, it is likely that the bloom was caused by rapid in situ growth of phytoplankton with high nutrients and sufficient light. The data also indicated that the duration of the bloom was not long and

A recent shellfish toxin investigation in China

A shellfish toxin investigation along the Chinese coast has recently been conducted using both HPLC and mouse assay methods. The results showed that DSP was widely distributed in different shellfish species in China. 26 out of 89 samples had DTX1 (dinophysistoxin-1) or OA (okadaic acid) but the DSP content in most shellfish samples did not reach the regulatory limit for human consumption adopted in many countries (20 mu g/100 g soft tissue). PSP was also found in 5 out of 96 samples along the coast. One sample, Chlamys nobilis from Hong Kong contained high levels of PSP (320 mu g STX equivalent/100 g soft tissue), compared to the regulatory limit (80 mu g STX equivalent/100 g soft tissue). After the recent outbreak of red tide in Hong Kong waters, three further shellfish samples were collected within 40 days to investigate the impacts of this event, It was shown that high levels of PSP continued to exist in Hong Kong waters. This report provides the first report of DSP and PSP distribution along the Chinese coast. (C) 1999 Elsevier Science Ltd, All rights reserved.

Impact of germanium on the growth of Pseudonitzschia pungens f. multiseries and the production of algal toxin

The impacts of germanic acid Ge(OH)(4) on the growth of Psuedonitzschia pungens f. multiseries and on the production of the algal toxin, domoic acid, were studied. The results showed that germanic acid in the range of concentrations could inhibit the growth of the algal cells and the inhibition was enhancing with the concentrations of germanic acid increasing. Germanic acid also could inhibit the production of the algal toxin, domoic acid in cells and the inhibition reached up to 100% at Ge/Si = 35. Based on the results, the mechanism was discussed.

Environmental changes reflected by sedimentary geochemistry in recent hundred years of Jiaozhou Bay, North China

Sediment geochemical technique was employed to assess how the sediment records reflect the environmental changes of Jiaozhou Bay, a semi-enclosed bay adjacent to Qingdao, China. In the past hundred years, Jiaozhou Bay has been greatly impacted by human interventions. A dated core sediment by Pb-210 chronology was analyzed for trace metals including Li, Cd, Cr, Pb, Cu, Ni, Co, Zn together with C, N, P and BSi. Based on the research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages: (1) before the 1980s characterized by relatively low sedimentation rate, weak heavy metal pollution and scarce eutrophication; (2) from the 1980s to 2000, accelerating in the 1990s, during which high sedimentation rates, polluted by heavy metals and the frequent occurrence of red tide; (3) after 2000, the period of the improvement of environment, the whole system has been meliorated including the heavy metal pollution and hypernutrification. (c) 2006 Elsevier Ltd. All rights reserved.

Responses of a coastal phytoplankton community to increased nutrient input from the Changjiang (Yangtze) River

Nutrient input from the Changjiang River (Yangtze River) has been increasing dramatically since the 1960s. At the mouth of the Changjiang River, the nitrate concentration has increased about three-fold in 40 years, from 20.5 mu mol/L in the 1960s to 59.1 mu mol/L in the 1980s and to 80.6 mu mol/L in 1990-2004. Phosphate concentration increased by a factor of 30%, from 0.59 mu mol/L in the 1980s to 0.77 mu mol/L in 1990-2004. The increasing nitrate input has arisen mostly from the mid and lower reaches of the Changjiang River, where the river meets one of the most strongly developed agriculture areas in China. Responses of the coastal phytoplankton community to the increasing nutrient inputs are also seen in the available monitoring data. First, a trend of increasing phytoplankton standing stock from 1984 to 2002 appeared in the Changjiang River estuary and adjacent coastal waters, especially in late spring. Secondly, the proportion of diatoms in the whole phytoplankton community showed a decreasing trend from about 85% in 1984 to about 60% in 2000. Finally, red tides/harmful algal blooms increased dramatically in this area in terms of both number and scale. About 30-80 red tide events were recorded each year from 2000 to 2005 in the East China Sea. The scale of some blooms has been in excess of 10,000 km(2). (c) 2008 Elsevier Ltd. All rights reserved.

PHYLOGEOGRAPHIC PATTERNS INDICATE TRANSATLANTIC MIGRATION FROM EUROPE TO NORTH AMERICA IN THE RED SEAWEED CHONDRUS CRISPUS (GIGARTINALES, RHODOPHYTA)1

Inferring how the Pleistocene climate oscillations have repopulated the extant population structure of Chondrus crispus Stackh. in the North Atlantic Ocean is important both for our understanding of the glacial episode promoting diversification and for the conservation and development of marine organisms. C. crispus is an ecologically and commercially important red seaweed with broad distributions in the North Atlantic. Here, we employed both partial mtDNA Cox1 and nrDNA internal transcribed spacer region 2 (ITS2) sequences to explore the genetic structure of 17 C. crispus populations from this area. Twenty-eight and 30 haplotypes were inferred from these two markers, respectively. Analysis of molecular variance (AMOVA) and of the population statistic Theta(ST) not only revealed significant genetic structure within C. crispus populations but also detected significant levels of genetic subdivision among and within populations in the North Atlantic. On the basis of high haplotype diversity and the presence of endemic haplotypes, we postulate that C. crispus had survived in Pleistocene glacial refugia in the northeast Atlantic, such as the English Channel and the northwestern Iberian Peninsula. We also hypothesize that C. crispus from the English Channel refugium repopulated most of northeastern Europe and recolonized northeastern North America in the Late Pleistocene. The observed phylogeographic pattern of C. crispus populations is in agreement with a scenario in which severe Quaternary glaciations influenced the genetic structure of North Atlantic marine organisms with contiguous population expansion and locally restricted gene flow coupled with a transatlantic dispersal in the Late Pleistocene.

Cadmium toxicity to embryonic-larval development and survival in red sea bream Pagrus major

At 18 degrees C and 33 psu, 24 and 48 h LC50 values of cadmium (Cd) for red sea bream Pagrus major embryos were 9.8 and 6.6 mg l(-1), respectively, while 24,48, 72, and 96 h LC50 values for larvae were 18.9,16.2, 8.0, and 5.6 mg l(-1), respectively, indicating that embryos were more sensitive to Cd toxicity than larvae. Cd concentrations at >= 0.8 mg l(-1) led to low hatchability (0-90% in >= 0.8 mg l(-1) solutions vs. 97-100% in lower ones), delay in time to hatch, high mortality (38-100% vs. 1-10%), morphological abnormality (42-100% vs. 1-10%), reduced length (3.55-3.60 vs. 3.71-3.72 mm) in the embryos and larvae. They were Cd concentration dependent and potential biological significant endpoints for assessing the risk of Cd to aquatic organisms. Heart beat and yolk absorption of the larvae were significantly inhibited at some high concentrations but they were not as sensitive as other endpoints to Cd exposure. (C) 2008 Elsevier Inc. All rights reserved.

Diversity of pigment-protein complexes of photosynthetic organisms.

PS I, PS II and light-harvesting complexes (LHC) in oxygen evolving photosynthetic organisms were reviewed. These organisms include cyanobacteria, red algae, brown algae, diatoms, chrysophytes, dinophytes, xanthophytes, crypophytes, green algae and green plants. The diversity of pigment-protein complexes that fuel the conversion of radiant energy to chemical bond energy was highlighted, and the evolutionary relationships among the LHC structural polypeptides and the characteristics of the fluorescence emission of PS I at 77 K was discussed.

Red-shift conical emission by femtosecond pulses at low input power

Red-shift conical emission (CE) is observed by femtosecond laser pulse propagating in BK7 at a low input power (compared to those input powers for generation of blue-shift CE). With the increasing input power the blue-shift CE begins to appear whereas the red-shift CE ring (902 nm in our experiment) disappears accompanied by the augment of the central white spot size synchronously. The disappearing of red-shift CE in our experiment is explained such that the increase of axial intensity is much higher than that of ring emission and the augment of the central white spot size with the increasing input laser power.

Red shift and broadening of backward harmonic radiation from electron oscillations driven by femtosecond laser pulse

The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron's backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.

Study of the effect of alcohol on single human red blood cells using near-infrared laser tweezers Raman spectroscopy

The effect of alcohol solution on single human red blood Cells (RBCs) was investigated using near-infrared laser tweezers Raman spectroscopy (LTRS). In our system, a low-power diode laser at 785 nm was applied for the trapping of a living cell and the excitation of its Raman spectrum. Such a design could simultaneously reduce the photo-damage to the cell and suppress the interference from the fluorescence on the Raman signal. The denaturation process of single RBCs in 20% alcohol solution was investigated by detecting the time evolution of the Raman spectra at the single-cell level. The vitality of RBCs was characterized by the Raman band at 752 cm(-1), which corresponds to the porphyrin breathing mode. We found that the intensity of this band decreased by 34.1% over a period of 25 min after the administration of alcohol. In a further study of the dependence of denaturation on alcohol concentration, we discovered that the decrease in the intensity of the 752 cm(-1) band became more rapid and more prominent as the alcohol concentration increased. The present LTRS technique may have several potential applications in cell biology and medicine, including probing dynamic cellular processes at the single cell level and diagnosing cell disorders in real time. Copyright (c) 2005 John Wiley T Sons, Ltd.

Red laser-induced domain inversion in MgO-doped lithium niobate crystals

A laser beam at wavelength 647 nm is focused on a sample of 5 mol% MgO-doped lithium niobate crystal for domain inversion by a conventional external electric field. In this case, a reduction of 36% in the electric field required for domain nucleation (nucleation field) is observed. To the best of our knowledge, it is the longest wavelength reported for laser-induced domain inversion. This extends the spectrum of laser inducing, and the experimental results are helpful to understand the nucleation dynamics under laser illumination. The dependence of nucleation fields on intensities of laser beams is analysed in experiments.