Preliminary study on different nutrient pools supplies for the phytoplankton growth in the Jiaozhou Bay in China in the fall of 2004

The source and significance. of two mitrients, nitrogen. and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton, maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d(-1) outside the bay, 0.42 and 0.32 d(-1) inside the bay and 0.98 and 0.62 d(-1) in the harbor respectively. Outside the bay, the remineralized nitrogen (K-r = 24.49) had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus(K-r = 3.49) strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus (K-r = 3.73) was in larger demand by phytoplankton growth. The results demonstrated that the different nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that, nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed.

Numerical Solutions for the Transient Flow in the Homogenous Closed Circle Reservoirs

There are many fault block fields in China. A fault block field consists of fault pools. The small fault pools can be viewed as the closed circle reservoirs in some case. In order to know the pressure change of the developed formation and provide the formation data for developing the fault block fields reasonably, the transient flow should be researched. In this paper, we use the automatic mesh generation technology and the finite element method to solve the transient flow problem for the well located in the closed circle reservoir, especially for the well located in an arbitrary position in the closed circle reservoir. The pressure diffusion process is visualized and the well-location factor concept is first proposed in this paper. The typical curves of pressure vs time for the well with different well-location factors are presented. By comparing numerical results with the analytical solutions of the well located in the center of the closed circle reservoir, the numerical method is verified.

放牧对典型草原土壤-植物系统中碳、氮、磷库特征的影响

放牧是内蒙古典型草原最主要的利用方式。放牧已对草原生态系统的结构和功能产生了巨大的影响。本论文研究了放牧对内蒙古典型草原土壤-植物系统中碳、氮、磷库特征的影响，结果表明： （1）草地开垦已使土壤C、N贮量显著损失。放牧已使羊草草原土壤C贮量表现出下降的趋势，大针茅草原没有表现出这种变化趋势。 （2）放牧尚没有使土壤全N发生显著变化，但土壤N素一些组分的比例发生了变化。放牧后，土壤NH_3-N下降，酸不溶态N比例有所提高;放牧使Fe-P比例显著降低。 （3）蒙古草原土壤微生物量C、N与土壤有机C、全N、降雨量、温度均表现出了很好的相关性。放牧对微生物量的影响与不同草原类型和放牧率有关。 （4）放牧使土壤养分元素的空间异质性加大。退化草地恢复过程中小叶锦鸡儿灌丛诱导了植物组成、生物量和土壤化学元素含量在空间上的分异，这种生态效应有利于退化草地的恢复。 （5）不同放牧强度对土壤C、N、P库和植物系统中C、N、P含量的影响不同。放牧使植物系统地上部C含量下降，N、P含量提高。高强度的放牧使土壤N、根系中的N素向表层相对聚集，表现出明显的表聚化现象。植物C/N、C/P比在中、重度放牧强度下最低，此时植物残体分解速率最高，极度放牧最终C、N循环速率减小。不考虑放牧率，研究放牧对土壤C、N、P含量的影响可能会得出矛盾的结论。 （6）放牧草地中低等植物地衣、蓝细菌在元素化学循环中的作用提高。地衣Xanthoparmelia camtschadalis （Ach.）的生物量在经度放牧草地中最高，其体内C、N含量与放牧率的关系与维管植物相似。退化草地中蓝细菌可能是最重要的N素来源。

改变土壤碳输入对我国北方温带草原土壤碳、氮库和碳、氮循环的影响

土壤是陆地生态系统最重要的碳库和氮库，在陆地生态系统碳氮循环过程中起着举足轻重的作用。植物光合作用产物向地下的分配(根系分泌、细胞凋亡和根系分解)和地上凋落物分解是土壤碳两个最主要的来源，关于这两种碳输入途径和量如何影响陆地生态系统土壤碳氮库和循环的有限理解，限制了我们预测陆地生态系统碳循环对于全球气候变化的响应和反馈。本实验以我国北方广泛分布的温带典型草原生态系统为研究对象，通过添加和去除地面凋落物以及割草改变植物对土壤的碳输入途径和量，观察温带草原土壤有机碳库和氮库各个组分(微生物生物量碳氮、活性碳、可溶性碳、轻重组碳、总有机碳、总有机氮)及碳氮循环(微生物呼吸、土壤呼吸、生态系统气体交换、净氮矿化)的变化，来区分和量化凋落物分解和根系分泌、分解这两种碳输入方式对草原土壤碳库和循环的相对贡献和影响，有助于揭示在全球变化背景下温带典型草原生态系统碳库和碳循环的响应机制，并为预测其未来变化动态以及对全球气候变化的反馈提供参数估计和模型校正和验证。 我们对各处理样方土壤温度、土壤水分以及土壤呼吸进行了一个生长季的测定，结果表明，添加和去除凋落物都使得土壤呼吸与对照相比都有所增加，但是都没有达到显著水平;而无论地上凋落物的量添加、去除还是不变，植物光合作用对土壤呼吸的影响则比较显著，去除植物显著地降低了土壤呼吸。这说明处理一年后，植物对土壤呼吸起主导作用，而凋落物处理对土壤呼吸的影响还需要更长时间的观察。此外，生物量的结果也表明了地上凋落物的改变会影响到植物生长，从而影响到植物对土壤的碳输入，但是都没有达到显著水平，仍然需要我们进行更长时间的处理和观察。 通过在生长季前期、中期、后期进行了三次氮矿化的测定，以及在生长季后期进行了一次微生物生物量测定，我们得出以下结论：添加凋落物加快了净氮矿化速率，但是没有达到显著影响水平;同样，去除凋落物降低了净氮矿化速率，也没有达到显著水平。此外，添加凋落物处理微生物生物量碳、氮都有所增加，与对照相比没有显著差异，但是显著高于另外几个处理。 通过本研究，我们对于根系分泌和地上凋落物分解这两种碳氮输入途径对我国温带草原碳氮循环的影响有了初步的了解。与森林生态系统相比，由于草原生态系统土壤碳氮含量低，土壤碳库和转化对碳输入途径和量的变化更为敏感，在处理第一年，土壤微生物量和土壤呼吸都发生了显著的变化。然而，由于改变土壤碳库是长时间日积月累的结果，草原生态系统某些指标对碳输入途径和量的变化的响应还需要较长时间才能显示出来，例如添加和去除凋落物虽然使得土壤呼吸值有所增加，但是还都没有达到显著的水平;另外碳输入途径和量的变化对草原生态系统氮矿化还没有产生显著的影响。这些都需要更长时间的处理和观测来验证。

Frog skins keep redox homeostasis by antioxidant peptides with rapid radical scavenging ability

The question of how amphibians can protect themselves from reactive oxygen species when exposed to the sun in an oxygen-rich atmosphere is important and interesting, not only from an evolutionary viewpoint, but also as a primer for researchers interested in mammalian skin biology, in which such peptide systems for antioxidant defense are not well studied. The identification of an antioxidant peptide named antioxidin-RL from frog (Odorrana livida) skin in this report supports the idea that a peptide antioxidant system may be a widespread antioxidant strategy among amphibian skins. Its ability to eliminate most of the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical tested within 2 s, which is much faster than the commercial antioxidant factor butylated hydroxytoluene, suggests that it has a potentially large impact on redox homeostasis in amphibian skins. Cys10 is proven to be responsible for its rapid radical scavenging function and tyrosines take part in the binding of antioxidin-RL to radicals according to our nuclear magnetic resonance assay. (C) 2010 Elsevier Inc. All rights reserved.

Phylogeny of mitochondrial DNA macrohaplogroup N in India, based on complete sequencing: Implications for the peopling of South Asia

To resolve the phylogeny of the autochthonous mitochondrial DNA (mtDNA) haplogroups of India and determine the relationship between the Indian and western Eurasian mtDNA pools more precisely, a diverse subset of 75 macrohaplogroup N lineages was chosen fo

Mitochondrial DNA mutation m.3635G > A may be associated with Leber hereditary optic neuropathy in Chinese

Leber hereditary optic neuropathy (LHON) was the first disease to be linked to the presence of a mitochondrial DNA (mtDNA) mutation. Nowadays over 95% of LHON cases are known to be caused by one of three primary mutations (m.11778G>A, m.14484T>C, and m.34

Median network analysis of defectively sequenced entire mitochondrial genomes from early and contemporary disease studies

Sequence analysis of the mitochondrial genome has become a routine method in the study of mitochondrial diseases. Quite often, the sequencing efforts in the search of pathogenic or disease-associated mutations are affected by technical and interpretive pr

Spatial and seasonal variations in benthic algal assemblages in streams in monsoonal Hong Kong

Samples from stone surfaces were collected in pools within four unpolluted hillstreams (two shaded and two unshaded) in monsoonal Hong Kong (lat. 23 degrees N) to elucidate the extent of spatial (within and among streams) and temporal (seasonal) variations in algal biomass and assemblage composition. Sampling continued for over 12 months, incorporating the dry season when streams were at baseflow, and the wet season when spates were frequent. We anticipated that algal biomass would be lower in shaded streams and during the wet season, with associated seasonal differences in assemblage composition or relative abundance of different growth forms (e. g. erect versus prostrate). Benthic chlorophyll a (a proxy for algal biomass) varied among streams from an annual mean of 11.0-22.3 mg m(-2). Dry-season standing stocks were 18% higher than during the wet season when spate-induced disturbance reduced algal standing stocks. Algal biomass varied significantly at the stream scale, but not at the pool scale, and was lower in unshaded streams, where standing stocks may have been limited by high densities of algivorous balitorid loaches (mainly Pseudogastromyzon myersi). An overriding effect of grazers on algal biomass could also have reduced variations resulting from spate-induced disturbance. Significant differences in assemblage composition among streams, which were dominated by diatoms and cyanobacteria (totally 82 taxa) were not systematically related to shading conditions. Seasonal variations in algal assemblages were statistically significant but rather minor, and did not involve major shifts in composition or growth form caused by spate-induced disturbance. The abundance of filamentous cyanobacteria in all the streams may have been due to 'gardening' by balitorid loaches that removed erect or stalked diatoms and favoured cyanobacteria that persist through basal regeneration of filaments. This explanation requires validation through manipulative experiments.

Identification of differential transcript profiles between mutual crossbred embryos of zebrafish (Danio rerio) and Chinese rare minnow (Gobiocypris rarus) by cDNA-AFLP

The crosstalk between naive nucleus and maternal factors deposited in egg cytoplasm before zygotic genome activation is crucial for early development. In this study, we utilized two laboratory fishes, zebrafish (Danio rerio) and Chinese rare minnow and Chinese rare minnow (Gobiocypris rarus), to obtain mutual crossbred embroys and examine the interaction between nucleus and egg cytoplasm from different species. Although these two types of crossbred embryos originated from common nuclei, various developmental capacities were gained due to different origins of the egg cytoplasm. Using cDNA amplified fragment length polymorphism (cDNA-AFLP), We Compared transcript profiles between the mutual crossbred embryos at two developmental stages (50%- and 90%-epiholy). Three thousand cDNA fragments were generated in four cDNA pools with 64 primer combinations. All differently displayed transcript-derived fragments (TDFs) were screened by (lot blot hybridization, and the selected sequences were further analyzed by semi-quantitative RT-PCR and quantitative real-time RT-PCR. Compared with ZR embryos, 12 genes were up-regulated and 12 were down-regulated in RZ embryos. The gene fragments were sequenced and subjected to BLASTN analysis. The sequences encoded various proteins which functioned at various levels of proliferation, growth, and development. One gene (ZR6), dramatically down-regulated in RZ embryos, was chosen for loss-of-function study; the knockdown of ZR6 gave rise to the phenotype resembling that of RZ embryos. (c) 2008 Elsevier Inc. All rights reserved.

Relationships among the contents of total phenolics, soluble carbohydrate, and free amino acids of 15 aquatic macrophytes

In order to examine how carbon and nitrogen status of a macrophyte may affect its total phenolics (TP) production, the contents of free amino acids (FAA), soluble carbohydrate (SC) and TP were examined in leaves of seven submersed, four floating-leaved, and four emergent macrophytes. The floating-leaved and emergent macrophytes had much higher contents of SC and TP than the submersed macrophytes. The contents of FAA were not significantly different among the submersed, floating-leaved, and emergent macrophytes. Correlations among the contents of FAA, SC, and TP indicated that the production of TP was more dependent on the SC content than on the FAA content.

A new fluorescent quantitative PCR-based in vitro neutralization assay for white spot syndrome virus

A fluorescent quantitative PCR (FQ-PCR) assay utilizing SYBR green I dye is described for quantitation of white spot syndrome virus (WSSV) particles isolated from infected crayfish, Cambarus clarkii. For this assay, a primer set was designed which amplifies, with high efficiency and specificity, a 129 bp target sequence within ORF167 of the WSSV genome. Conveniently, WSSV particles can be added into the FQ-PCR assay with a simple and convenient method to release its DNA. To establish the basis for an in vitro neutralization test, primary cultures of shrimp cells were challenged with WSSV that had been incubated with a polyclonal anti-WSSV serum or with control proteins. The number of WSSV particles released from the cells after these treatments were assayed by FQ-PCR. This test may serve as a method to screen monoclonal antibody pools or recombinant antibody pools for neutralizing activity prior to in vivo animal experiments. (c) 2007 Elsevier B.V. All rights reserved.