Expression and localization of a novel phosducin-like protein from amphioxus Branchiostoma belcheri

A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP), was identified for the first time from the gut cDNA library of Branchiostoma belcheri. It is comprised of 1 550 bp and an open reading frame (ORF) of 241 amino acids, with a predicted molecular mass of approximately 28 kDa. In situ hybridization histochemistry revealed a tissue-specific expression pattern of Amphi-PhLP with the high levels in the ovary, and at a lower level in the hind gut and testis, hepatic caecum, gill, endostyle, and epipharyngeal groove, while it was absent in the muscle, neural tube and notochord. In the Chinese Hamster Ovary (CHO) cells transfected with the expression plasmid pEGFP-N1/Amphi-PhLP, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that Amphi-PhLP is a cytosolic protein. This work may provide a framework for further understanding of the physiological function of Amphi-PhLP in B. belcheri.

Development of the East Asian summer monsoon: Evidence from the sediment record in the South China Sea since 8.5 Ma

128 samples from Ocean Drilling Program (ODP) Site 1143 in the southern South China Sea were analyzed for grain size, clay minerals, biogenic opal content and quartz in order to reconstruct changes in East Asian monsoon climate since 8.5 Ma. An abrupt change of terrigenous mass accumulation rate (MAR), clay mineral assemblage, median grain size and biogenic opal MAR about 5.2 Ma suggests that between 8.5-5.2 Ma the source of terrigenous sediment was mainly in the region of surface uplift and basaltic volcanism in southern Vietnam. A simple model of East Asian summer monsoon evolution was based on the clay/feldspar ratio, kaolinite/chlorite ratio and biogenic opal MAR. The summer monsoon has two periods of maximum strength at 8.5-7.6 Ma and 7.1-6.2 Ma. Subsequently, there was a relatively stable period at 6.2-3.5 Ma, continued intensification about 3.5-2.5 Ma, and gradually weakening after 2.5 Ma. Since I Ma the monsoon has intensified, with remarkable high-frequency and amplitude variability. Simultaneous increase in sedimentation rates at ODP Sites 1143, 1146 and 1148, as well as in MAR of terrigenous materials, quartz, feldspar and clay minerals at ODP Site 1143 at 3.5-2.5 Ma, may be the erosional response to both global climatic deterioration and the strengthening of the East Asian summer monsoon after about 3-4 Ma. (c) 2006 Elsevier B.V. All rights reserved.

Modulatory effects of ammonia-N on the immune system of Penaeus japonicus to virulence of white spot syndrome virus

To study response to white spot syndrome virus (WSSV) under ammonia stress, Penaeus japonicus were exposed to 5 mg l(-1) ammonia-N and challenged orally with WSSV (NW). Controls consisted of an ammonia-N-exposed control group (N), a WSSV-challenged positive control group (W), and an untreated control group (control). Immune parameters measured were total haemocyte count (THC), haemocyte phagocytosis, plasma protein content and haemolymph enzymatic activities for prophenoloxidase (proPO), alkaline phosphatase (ALP), and nitric oxide synthase (NOS). THC and plasma protein had downward trends with time in all treatment groups (NW, N, and W) in contrast to the untreated control group (control). The percentage phagocytosis, NOS activity, and ALP and proPO activity of W and NW decreased initially then increased from 6 to 78 h (except for NOS and ALP, from 6 to 54 h) before declining thereafter until the end of the experiment. Compared with untreated controls (control), there was a downward trend for all measured parameters in the treatment groups (N, NW, and W), but the degree was W > NW > N. WSSV was detected at 78 h postchallenge in both W and NW. In conclusion, 5 mg l(-1) ammonia-N reduced the immunocompetence of P japonicus and may have decreased the virulence of WSSV (C) 2004 Elsevier B.V. All rights reserved.

Sources and transport of dissolved and particulate organic carbon in the Mississippi River estuary and adjacent coastal waters of the northern Gulf of Mexico

Dissolved organic carbon (DOC), stable carbon isotopic (delta(13)C) compositions of DOC and particulate organic carbon (POC), and elemental C/N ratios of POC were measured for samples collected from the lower Mississippi and Atchafalaya rivers and adjacent coastal waters in the northern Gulf of Mexico during the low flow season in June 2000 and high flow season in April 2001. These isotopic and C/N results combined with DOC measurements were used to assess the sources and transport of terrestrial organic matter from the Mississippi and Atchafalaya rivers to the coastal region in the northern Gulf of Mexico. delta(13)C values of both POC (-23.8parts per thousand to -26.8parts per thousand) and DOC (-25.0parts per thousand to -29.0parts per thousand) carried by the two rivers were more depleted than the values measured for the samples collected in the offshore waters. Strong seasonal variations in delta(13)C distributions were observed for both POC and DOC in the surface waters of the region. Fresh water discharge and horizontal mixing played important roles in the distribution and transport of terrestrial POC and DOC offshore. Our results indicate that both POC and DOC exhibited non-conservative behavior during the mixing especially in the mid-salinity range. Based on a simple two end-member mixing model, the comparison of the measured DOC-delta(13)C with the calculated conservative isotopic mixing curve indicated that there was a significant in situ production of marine-derived DOC in the mid- to high-salinity waters consistent with our in situ chlorophyll-a measurements. Our DOC-delta(13)C data suggest that a removal of terrestrial DOC mainly occurred in the high-salinity (>25) waters during the mixing. Our study indicates that the mid- to high- (10-30) salinity range was the most dynamic zone for organic carbon transport and cycling in the Mississippi River estuary. Variability in isotopic and elemental compositions along with variability in DOC and POC concentrations suggest that autochthonous production, bacterial utilization, and photo-oxidation could all play important roles in regulating and removing terrestrial DOC in the northern Gulf of Mexico and further study of these individual processes is warranted. (C) 2004 Elsevier B.V. All rights reserved.

Transfer of paralytic shellfish toxins via marine food chains: A simulated experiment

Objective To study the transfer of paralytic shellfish toxins (PST) using four simulated marine food chains: dinoflagellate Alexandrium tamarense -> Arterriia Artemia salina -> Mysid shrimp Neomysis awatschensis; A. tamarense-N. awatschensis: A. taniarense A. salina -> Perch Lateolabrax japonicus; and A. tamarense -> L. japonicus. Methods The ingestion of A. tamarense, a producer of PST, by L. japonicus, N. awatschensis, and A. salina was first confirmed by microscopic observation of A. tamarense cells in the intestine samples of the three different organisms, and by the analysis of Chl.a levels iii the samples. Toxin accumulation in L. japonicus and N. awatschensis directly from the feeding on A. tamarense or indirectly ibrough the vector of A. salina was then studied. The toxicity of samples was measured using the AOAC mouse bioassay method, and the toxin content and profile of A. tamarense were analyzed by the HPLC method. Results Both A. salina and N. awatschensis could ingest A. tamarense cells. However, the ingestion capability of A. salina exceeded that of N. awatschensis. After the exposure to the culture of A. tamarense (2 000 cells(.)mL(-1)) for 70 minutes, the content of ChLa in A. salina and N. awatschensis reached 0.87 and 0.024 mu g-mg(-1), respectively. Besides, A. tamarense cells existed in the intestines of L. japonicus, N. awatschensis and A. salina by microscopic observation. Therefore, the three organisms could ingest A. tamarense cells directly. A. salina could accumulate high content of PST, and the toxicity of A. salina in samples collected on days 1, 4, and 5 of the experiment was 2.18, 2.6, and 2.1 MU(.)g(-1), respectively. All extracts from the samples could lead to death of tested mice within 7 minutes, and the toxin content in arternia sample collected on the 1st day was estimated to be 1.65x10(-5) pg STX equa Vindividual. Toxin accumulation in L. japonicus and N. awatschensis directly from the feeding on A. tamarense or indirectly froin the vector of A. salina was also studied. The mice injected with extracts from L. japonicus and N. awatschensis samples that accumulated PST either directly or indirectly showed PST intoxication symptoms, indicating that low levels of PST existed in these samples. Conclusion Paralytic shellfish toxins can be transferred to L. japonicus, N. awatschensis, and A. salina from A. taniarense directly or indirectly via the food chains.

Intra-habitat heterogeneity of microbial food web structure under the regime of eutrophication and sediment resuspension in the large subtropical shallow Lake Taihu, China

Planktonic microbial community structure and classical food web were investigated in the large shallow eutrophic Lake Taihu (2338 km(2), mean depth 1.9 m) located in subtropical Southeast China. The water column of the lake was sampled biweekly at two sites located 22 km apart over a period of twelve month. Site 1 is under the regime of heavy eutrophication while Site 2 is governed by wind-driven sediment resuspension. Within-lake comparison indicates that phosphorus enrichment resulted in increased abundance of microbial components. However, the coupling between total phosphorus and abundance of microbial components was different between the two sites. Much stronger coupling was observed at Site 1 than at Site 2. The weak coupling at Site 2 was mainly caused by strong sediment resuspension, which limited growth of phytoplankton and, consequently, growth of bacterioplankton and other microbial components. High percentages of attached bacteria, which were strongly correlated with the biomass of phytoplankton, especially Microcystis spp., were found at Site 1 during summer and early autumn, but no such correlation was observed at Site 2. This potentially leads to differences in carbon flow through microbial food web at different locations. Overall, significant heterogeneity of microbial food web structure between the two sites was observed. Site-specific differences in nutrient enrichment (i.e. nitrogen and phosphorus) and sediment resuspension were identified as driving forces of the observed intra-habitat differences in food web structure.

A preliminary genetic linkage map of the pacific abalone Haliotis discus hannai Ino

Preliminary genetic linkage maps were constructed for the Pacific abalone (Haliotis discus hannai Ino) using amplified fragment length polymorphism (AFLP), randomly amplified polymorphic DNA (RAPD), and microsatellite markers segregating in a F, family. Nine microsatellite loci, 41 RAPD, and 2688 AFLP markers were genotyped in the parents and 86 progeny of the mapping family. Among the 2738 markers, 384 (including 365 AFLP markers, 10 RAPD markers, and 9 microsatellite loci) were polymorphic and segregated in one or both parents: 241 in the female and 146 in the male. The majority of these markers, 232 in the female and 134 in the male, segregated according to the expected 1:1 Mendelian ratio (alpha = 0.05). Two genetic linkage maps were constructed using markers segregating in the female or the male parent. The female framework map consisted of 119 markers in 22 linkage groups, covering 1773.6 cM with an average intermarker space of 18.3 cM. The male framework map contained 94 markers in 19 linkage groups, spanning 1365.9 cM with an average intermarker space of 18.2 cM. The sex determination locus was mapped to the male map but not to the female map, suggesting a XY-male determination mechanism. Distorted markers showing excess of homozygotes were mapped in clusters, probably because of their linkage to a gene that is incompatible between two parental populations.

Hydrogen permeation and corrosion behaviour of high strength steel 35CrMo under cyclic wet-dry conditions

Hydrogen permeation behaviours of high strength steel 35CrMo under different cyclic wet-dry conditions have been investigated by using Devanathan-Stachurski's technique. Four electrolytes were used: distilled water, seawater, seawater containing 1500 ppm H2S and seawater containing 0.03 mol L-1 SO2. The corrosion weight loss of 35CrMo in the wet-dry cycles was measured simultaneously. The experimental results show that hydrogen can be detected at the surface opposite to the corroding side of the specimen during wet-dry cycles and the permeation current density during a wet-dry cycle showed a maximum during the drying process. The hydrogen permeation was obviously promoted by Cl- ions, H2S and SO2. The hydrogen permeation in the real marine atmosphere has also been investigated. There is a clear correlation between the amount of hydrogen permeated and the corrosion weight losses. Results show the importance of hydrogen permeation that merits further investigation.

热休克反应与哺乳动物高海拔（缺氧）适应

利用免疫学和分子生物学手段研究哺乳动物的高海拔（缺氧）适应，通过哺乳动物热休克反应，了解热休克蛋白在生物体高海拔（缺氧）适应中的意义．用Western blot和常规RT-PCR及实时荧光定量PCR（real-time PCR detection）测定不同海拔哺乳动物（牦牛）心肌组织热休克蛋白70（Hsp70）的表达差异和脑组织中Hsp70基因的自然表达．将低海拔哺乳动物（家兔）直接送达不同高海拔地区（海拔2300，3300，5000m）喂养3周后宰杀，再用RT-PCR测定其脑组织中Hsp70基因的诱导表达．结果显示：不同海拔哺乳动物都具有热休克反应基因，应激时高海拔哺乳动物Hsp70表达快速升高；Hsp70可被高海拔（缺氧）诱导产生．热休克反应中Hsp70的快速合成有利于维持应激时细胞的正常生理功能，Hsp70的表达存在着阈值，海拔5000m是热休克反应最佳的条件，超过海拔6000m时热休克反应减弱；Hsp70生成量与细胞的耐缺氧能力成正比．

种群密度对高原鼠兔类固醇激素水平的影响

本研究于2003年在野外条件下，通过比较不同密度种群间高原鼠兔的种群增长、4种类固醇激素水平和肾上腺重量的变化，探讨种群密度与其内分泌水平间的相互关系。结果表明，在最高密度的种群内高原鼠兔种群密度增长最大，在最低密度种群内种群密度增长最小。繁殖盛期时高密度种群内雄性高原鼠兔血浆皮质酮水平显著高于低密度种群内个体，肾上腺重量在不同密度种群间也有显著差异，而血浆雌二醇、睾酮、皮质醇水平均未表现出种群密度间的显著变化。整个繁殖期内，高密度和低密度种群问高原鼠兔的皮质酮水平和。肾上腺重量呈现不一致的季节变化模式，高密度种群内繁殖盛期和中期显著高于其它繁殖时期，低密度种群内则无明显变化。不同密度种群内高原鼠兔的雌二醇、睾酮、皮质醇水平的季节性变化具有相似的模式。本研究结果表明，在当前种群密度相对较低的自然情况下，高种群密度不能使高原鼠兔产生强烈的社群应激，从而限制其种群增长。

矮嵩草草甸生物量季节动态及其与气候因子的关系

测定高寒矮嵩草(Kobresia humilis)草甸地上、地下生物量季节动态,分析生物量季节动态与气候因子的相关性,建立了地上生物量动态变化的模拟模型.结果表明:高寒矮嵩草草甸地上生物量动态变化历经萌动期、返青期、旺盛生长期、稳定期和折损减少期等5个阶段;地下生物量自5-9月表现出升高-降低-升高的变化规律,且变化幅度较高;2003年地下净生产量633.46 g/m2,周转率0.3193;利用海北高寒草甸多年观测资料,建立了气象因子影响植被年生产量的预报模型.

巨穗小麦种质株高的基因定位

巨穗小麦新种质材料是一种有茎杆粗壮、叶片短宽直立、大穗、大粒 、高结实率等特点的种质资源。本研究应用单体分析和双端体分析方法对“241”材料进行了遗传学研究。结果表明，小麦新种质材料“241”的1A、3A、5A和4B染色体上具有控制株高的隐性基因，6B染色体上具有控制株高的显性基因，其中3A、5A和6B染色体上的基因表现为强效，1A和4B染色体上的基因表现为弱效。通过双端体分析进一步将控制株高的基因定位到1AS、3AS、5AL和4BL上。

巨穗小麦种质株高的基因定位

巨穗小麦新种质材料是一具有茎杆粗壮、叶片短宽直立、大穗、大粒、高结实率等特点的种质资源。本研究应用单体分析和双端体分析方法对241材料进行了遗传学研究。结果表明，小麦新种质材料241的1A，3A，5A和4B染色体上具有控制株高的隐性基因，6B染色体上具有控制株高的显性基因，其中3A，5A和6B染色体上的基因表现为强效，1A和4B染色体上的基因表现为弱效。通过双端体分析进一步将控制株高的基因定位到1AS，3AS，5AL和4BL上。

巨穗小麦种质小穗数的染色体定位研究

巨穗小麦新种质材料是一具有茎秆粗壮、叶片短宽直立、穗大、粒大、结实率高等特点的种质资源。应用单体分析和双端体分析方法对“241”材料进行遗传学研究，结果表明，小麦新种质材料“241”的3A、1B、2B和6B染色体上具有控制小穗数的隐性基因，其中3A、1B和2B染色体上的基因表现为强效，6B染色体上的基因表现为弱效。通过双端体分析进一步将控制小穗数的基因定位到3AS、1BL和6BS上，其中3AS、6BS上可能具有控制“241”小穗数的新基因。控制“241”穗粒数和控制小穗数的基因可能存在一定的连锁关系。

α—β石英相变的应变参数计算及其地质意义

利用已有的α和 β石英压缩性、热膨胀性、弹性及相变温度压力资料 ,计算了α—β石英相转变时 ,α和β石英的晶胞参数。依据虎克定律以及高压下 β石英的弹性参数 ,估算了α—β石英相转变时的应变、应力和应变能。结果表明 ,在 0～ 1 .1GPa条件下 ,随着压力升高 ,α—β石英相变的线应变介于 - 0 .0 0 6～ 0 .0 0 5之间 ,体应变介于 - 0 .0 1 6～ 0 .0 1 2之间 ,应力介于 - 0 .46～ 0 .1 4GPa之间 ;应变能介于 96 5～ 2 76 0kJ/m3之间。当压力为 0 .5GPa左右时 ,α—β石英相变的应变、应力和应变能均达到最小值。在此基础上 ,讨论了壳内大规模酸性岩浆活动引起的α—β石英相变对壳内岩石的作用。