Genetic diversity and selective breeding of red common carps in China

China has a very rich genetic diversity in common carp (Cyprinus carpio) and the red common carp plays an important role in Chinese aquaculture and genetic studies. Selective breeding, particularly crossbreeding has been applied successfully to red common carps in China, and the products of these efforts have been in commercial use since the 1970s. However, knowledge of the quantitative and molecular genetics of these carps is limited. Studies were therefore undertaken to: (1) understand the genetic diversity and genetic relationship of red common carps in China; (2) understand the inheritance of color phenotype of Oujiang color carp; (3) select stable Oujiang color carp with fast growth rate and ornamental Oujiang color carp comparable with the Koi common carp from Japan; (4) study the culture performance and culture systems suitable for the Oujiang color carp in cages and paddies; (5) extend better quality fish and appropriate culture systems for small scale fish farmers in poor areas.

Diferenciação genética do golfinho-de-dentes-rugosos, Steno bredanensis (Cuvier in Lesson, 1828) (Cetartiodactyla: Delphinidae): taxonomia molecular e estrutura populacional

O gênero Steno pertence à Ordem Cetartiodactyla, Família Delphinidae, e compreende apenas uma espécie: o golfinho-de-dentes-rugosos, Steno bredanensis. O golfinho-de-dentes-rugosos é encontrado nos Oceanos Atlântico, Pacífico e Índico, em águas profundas tropicais, subtropicais e temperadas quentes. Entretanto, em algumas localidades como as regiões Sudeste e Sul do Brasil, esta espécie é conhecida por apresentar hábitos costeiros, o que a torna suscetível a ameaças antropogênicas como a degradação do hábitat, as capturas acidentais e diversos tipos de poluição. Conhecer a magnitude destes impactos e o grau de diferenciação genética das populações usando marcadores moleculares são aspectos importantes para a conservação da espécie. Os marcadores moleculares são segmentos específicos de DNA que podem ou não fazer parte de um gene e que apresentam grau de polimorfismo adequado para responder questões sobre as relações genéticas de indivíduos, populações ou diferentes espécies. O DNA mitocondrial é um dos marcadores moleculares mais utilizados em estudos sobre estrutura populacional, sistemática e filogenia de cetáceos. Estudos genéticos têm mostrado que várias espécies de delfinídeos apresentam estrutura populacional genética, entre e dentro das bacias oceânicas. No presente estudo foi investigada a diferenciação genética do golfinho-de-dentes-rugosos usando sequências da região controle mitocondrial de várias localidades em todo o mundo (Oceano Pacífico Centro-Sul: N=59; Pacífico Tropical Leste: N= 4; Pacífico Noroeste: N=1; Oceano Índico: N=1; Atlântico - Caribe: N=3; Atlântico Sudoeste: N=44; N total = 112). Análises preliminares indicaram grande diferenciação genética entre os Oceanos Atlântico e Pacífico/Índico (distância p = 0,031), que foram posteriormente investigadas utilizando sequências do citocromo b e mitogenomas completos. As análises filogenéticas de Neighbor-Joining e Bayesianas não foram conclusivas sobre a existência de especiação críptica em Steno. No entanto, a grande diferenciação entre as bacias oceânicas merece uma análise mais aprofundada, utilizando outros marcadores genéticos (por ex., sequências nucleares) bem como dados morfológicos. Não obstante, as análises AMOVA e FST par-a-par revelaram forte diferenciação populacional, não só entre os oceanos Atlântico e Pacífico, mas também no Atlântico, onde foram detectadas três populações: Caribe, região Sudeste e região Sul do Brasil. As populações detectadas no Atlântico Sudoeste devem ser aceitas como Unidades de Manejo (Management Units, MU) e dados demográficos básicos precisam ser levantados para essas MU, a fim de possibilitar uma melhor avaliação dos impactos antrópicos sobre elas. Este estudo fornece a primeira perspectiva sobre a diferenciação genética mundial de S. bredanensis.

Isolation and characterization of 18 polymorphic microsatellite markers in Chinese mandarin fish Siniperca chuatsi (Basilewsky)

Eighteen microsatellite markers were isolated and characterized using an enrichment protocol in the Chinese mandarin fish Siniperca chuatsi (Basilewsky), a commercially important piscivorous fish in China. Out of 48 pairs of primers designed, 18 loci exhibited polymorphism with three to six alleles (mean 4.4 alleles/locus) and average observed heterozygosity ranged from 0.633 to 0.833 (mean 0.748) in a test population from Dongting Lake of China. Except for two loci, all other 16 loci were in the Hardy-Weinberg equilibrium. These markers would be useful for such studies as population genetics, ecology and selective breeding of the Chinese mandarin fish in future.

Identification, cloning, and characterization of microsatellite DNA in Euglena gracilis

Microsatellite DNA has been developed into one of the most popular genetic markers. We have identified and cloned microsatellite loci in the genome of a free-living protozoan Euglena gracilis FACHB-848, using the random amplified microsatellites method (RAMS). The digoxigenin-labelled oligonucleotides(CT)(10) and (GT)(10) served as probes to detect complementary sequences in the randomly amplified polymorphic DNA (RAPD) fingerprints produced by means of Southern blotting. Subsequently, positive RAPD fragments were cloned. From a total of 31 RAPD primer profiles, eight microsatellite loci of E. gracilis were detected and characterized. Further, six sites (i.e. EGMS1, EGMS3, EGMS4, EGMS5, EGMS6, and EGMS7) showed polymorphisms. We found a GT or CT microsatellite every 10.5 kb in the genome of E. gracilis, and similar to animal genomes, the (GT)(n) motif was much more abundant than the (CT)(n) motif. These polymorphic microsatellite DNA will serve as advantageous molecular markers for studying the genetic diversity and molecular ecology of Euglena.

Genetic divergence between Cyprinus carpio carpio and Cyprinus carpio haematopterus as assessed by mitochondrial DNA analysis, with emphasis on origin of European domestic carp

Although common carp is the major fish species in Asian and European aquaculture and many domestic varieties have occurred, there is a controversy about the origination of European domestic common carp. Some scientists affirmed that the ancestor of European domestic common carp was Danube River wild common carp, but others considered it might be Asian common carp. For elucidating origination of European domestic common carp, we chose two representative European domestic common carp strains (German mirror carp and Russian scattered scaled mirror carp) and one wild common carp strain of Cyprinus carpio carpio subspecies (Volga River wild common carp) and two Asian common carp strains, the Yangtze River wild common carp (Cyprinus carpio haematopterus) and traditionally domestic Xingguo red common carp, as experimental materials. ND5-ND6 and D-loop segments of mitochondrial DNA were amplified by polymerase chain reaction and analyzed through restriction fragment length polymorphism (RFLP) and sequencing respectively. The results revealed that HaeIII and DdeI digestion patterns of ND5-ND6 segment and sequences of control region were different between European subspecies C. carpio carpio and Asian subspecies C. carpio haematopterus. Phylogenetic analysis showed that German mirror carp and Russian scattered scaled mirror carp belonged to two subspecies, C. carpio carpio and C. carpio haematopterus, respectively. Therefore, there were different ancestors for domestic carp in Europe: German mirror carp was domesticated from European subspecies C. carpio carpio and Russian scattered scaled mirror carp originated from Asian subspecies C. carpio haematopterus.

Reproduction mode of an artificial allotetraploid carp (Pisces; Cyprinidae)

Mature eggs of allotetraploid carp were activated by inactive sperm or crossed with normal sperms of common carp (Cyprinus carpio), crucian carp (Carassius auratus), Chinese blunt snout bream (Megalobrama amblycephala), Hemiculter leucisculus and Pseudorasbora parva. Chromosome counts showed that all offspring of these crosses presented a mode number of 200 chromosomes (4n = 200), and their morphological traits are much like maternal. Microsatelite marker and RAPD patterns between allotetraploid maternal and its offspring, reproduced from different paternal species, were identical. Cytological, morphological and molecular evidences suggested that allotetraploid carp female nucleus would not fuse with any male nucleus and its reproduction mode might be gynogenesis and therefore their offspring are retaining their tetraploidy and give origin to clonal individuals.

Splitting the Fast and Slow Motions in Molecular Dynamics Simulations Based on the Change of Cold Potential Well Bottom

The atomic motion is coupled by the fast and slow components due to the high frequency vibration of atoms and the low frequency deformation of atomic lattice, respectively. A two-step approximate method was presented to determine the atomic slow motion. The first step is based on the change of the location of the cold potential well bottom and the second step is based on the average of the appropriate slow velocities of the surrounding atoms. The simple tensions of one-dimensional atoms and two-dimensional atoms were performed with the full molecular dynamics simulations. The conjugate gradient method was employed to determine the corresponding location of cold potential well bottom. Results show that our two-step approximate method is appropriate to determine the atomic slow motion under the low strain rate loading. This splitting method may be helpful to develop more efficient molecular modeling methods and simulations pertinent to realistic loading conditions of materials.

卧龙自然保护区不同海拔的中国沙棘(Hippophae rhamnoides subsp. sinensis)天然群体的遗传多样性分析

中国沙棘是一种雌雄异株、风媒传粉的灌木或乔木，在中国西南的卧龙自然保护区有广泛的分布。本研究以采集于四川卧龙自然保护区5 个海拔(1800 m、2200 m、2600 m、3000 m、3400 m)梯度的中国沙棘天然群体为材料，以ISSR 和AFLP 标记技术研究其遗传多样性水平及其遗传结构，旨在了解卧龙地区中国沙棘天然群体的遗传多样性水平以及遗传多样性在群体间、群体内以及雌雄亚群体间的分布和特征，为中国沙棘树种的遗传改良及种质资源保存提供遗传研究背景与实验依据。同时探讨ISSR、AFLP 和RAPD三种标记对中国沙棘天然群体的遗传变异水平和群体间遗传结构的评估能力和各自的优缺点。研究得出以下主要结论： 1. ISSR和AFLP分析都表明卧龙自然保护区的中国沙棘群体拥有较高的遗传变异水平(h = 0.249，HT = 0.305)。出现这种结果的主要原因可能与卧龙自然保护区多变的气候条件和生境的异质度大有关。 2. ISSR 和AFLP 都揭示出卧龙自然保护区中国沙棘群体的遗传多样性随着海拔的增加发生显著的变化，表现为中海拔群体(2200 m 和2600 m)比高海拔群体(3000 m 和3400 m)和低海拔群体(1800 m)有更高的遗传多样性的趋势。出现这种趋势的可能解释是低海拔群体处在相对高温和相对干旱的环境，高海拔群体受到低温和紫外线胁迫，而中海拔群体存在中国沙棘生长的适宜环境。 3. ISSR 和AFLP 分析都表明：卧龙自然保护区中国沙棘的遗传结构遵循分布范围广、交配系统以异交为主的木本植物的通常模式，即大多数的遗传变异存在于群体内，只有少部分的遗传变异存在于群体间。 4. 经Mantel 检测表明，卧龙自然保护区中国沙棘群体间的海拔距离和对应遗传距离之间存在显著的正相关关系，即随着垂直海拔距离的增加，群体间的遗传距离也随之增加。Mantel 检测结果以及聚类分析将卧龙自然保护区5 个不同海拔的中国沙棘群体分为低、中、高海拔群体三组的研究结果都表明，海拔很可能是限制群体间基因交流的主要因素。 5. ISSR 分析发现同一海拔的雌雄亚群体首先聚类的研究结果表明，同一海拔的雌雄亚群体在遗传上最相似。方差分析结果表明只有3.8%的总遗传变异存在于雌雄亚群体间，这可能与雌雄植株间的交配和遗传物质的混合有关。 6. ISSR、AFLP 和RAPD 分析都表明卧龙自然保护区不同海拔的中国沙棘天然群体的遗传多样性水平较高。它们的分析结果估算得到的Nei's 平均基因多样度(h)分别为0.249、0.214 和0.170。从该结果可以看出ISSR 和AFLP 比RAPD 检测到更多的遗传多态性,这很可能是不同标记检测的基因组的位点不同所致。 7. 依据对不同标记系统的比较分析，认为ISSR、AFLP 和RAPD 三种分子标记系统都能成功地用于调查卧龙自然保护区不同海拔的中国沙棘群体的遗传变异水平及遗传变异结构，提供关于中国沙棘天然群体多态性水平和遗传变异分布的有用信息。在三者中，AFLP 具有最高效能指数和标记指数，在确定种间分类关系或鉴别个体方面是一种比较理想的标记。 Hippophae rhamnoides subsp. sinensis, a dioecious and deciduous shrub species,occupies a wide range of habitats in the Wolong Nature Reserve, Southwest China. Ourpresent study investigated the pattern of genetic variation and differentiation among fivenatural populations of H. rhamnoides subsp. sinensis, occurring along an altitudinal gradientthat varied from 1,800 to 3,400 m above sea level in the Wolong Natural Reserve, by usingISSR and AFLP markers to guide its genetic improvement and germplasm conservation. And,comparative study of ISSR, AFLP and RAPD was performed to detect their capacity toestimating the level and pattern of genetic variation occurring among the five elevationpopulations of H. rhamnoides subsp. sinensis, and to discuss their application to the study onplant genetics. The results were list following: 1. The ISSR and AFLP analysis conducted for the H. rhamnoides subsp. sinensispopulations located in the Wolong Natural Reserve of China revealed the presence of highlevels of genetic variation (h = 0.249, HT = 0.305). Besides such features as relatively widedistribution, dominantly outcrossing mating system, and effective seed dispersal by small animals and birds, it is sometimes argued that hard climatic conditions and heterogeneous habitats may also contribute to high levels of diversity. 2. Genetic diversity of H. rhamnoides subsp. sinensis populations was found to varysignificantly with changing elevation, showing a trend that mid-elevation populations (2,200m and 2,600 m) were genetically more diverse than both low-elevation (1,800 m) andhigh-elevation populations (3,000 m and 3,400 m). H. rhamnoides subsp. sinensis is thoughtto be stressed by drought and high temperature at low elevations, and by low temperature athigh elevations. The high genetic variability present in the mid-elevation populations of H.rhamnoides subsp. sinensis is assumed to be related to a greater plant density in the middlealtitudinal zone, where favorable ecological conditions permit its continuous distributioncovering the zone from 2,200 m to 2,600 m above sea level. 3. The genetic structure of H. rhamnoides subsp. sinensis revealed by ISSRs andAFLPs followed the general pattern detected in woody species with widespread distributionsand outcrossing mating systems. Such plants possess more genetic diversity withinpopulations and less variation among populations than species with other combinations oftraits. 4. In the present study, Mantel tests showed positive correlations between altitudinaldistances and genetic distances among populations or subpopulations. The observedrelationship between altitude and genetic distances, and the result of the cluster analysisincluding populations or male subpopulations and classifying the groups into three altitudeclusters suggest that altitude is a major factor that restricts gene flow between populationsand subpopulations. 5. The analysis of molecular variance showed that only 3.8% of the variability residedbetween female and male subpopulations. Such a very restricted proportion of the totalmolecular variance between female and male subpopulations is due to common sexuality andmixing of genetic material between females and males. 6. The analysis based on ISSRs, AFLPs and RAPDs all revealed relatively high levelsof genetic variation among different altitudinal populations of H. rhamnoides subsp. sinensisin Wolong Natural Reserve of China. Their estimates of mean Nei’s gene diversity is equal to0.249, 0.214 and 0.170 respectively, suggesting the higher capacity of detecting geneticvariation of ISSR and AFLP than RAPD. It might be ascribed to their distinct sensitivity todifferent type of genetic variation. 7. Based on the coparative study on ISSR, AFLP and RAPD, we drew a conclusion thatthey all successfully reveal some useful information concerning the level and pattern ofgenetic vatiation occurring among different elevation populations of H. rhamnoides subsp.sinensis. AFLP is a ideal tool to taxonomic study and individual identification for theirhighest efficiency index and marker index among the three marker systems.

Relating the molecular structure and crystallization behavior of polypropylene

The crystallization behavior of two polypropylene (PP) resins as used for biaxially oriented polypropylene (BOPP) and general injection mold applications, respectively, has been intensively investigated and compared by means of polarized light optical micrography (POM), differential scanning calorimetry (DSC), conventional transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). It is found that both molecular weight distribution and isotacticity of polypropylene strongly affect its crystallization characteristics, e.g., the number of crystal nuclei at the initial stage, crystallization dynamics, the morphology, size and perfection of crystals in the final product, and so on. The results indicate an appropriate molecular structure is vital in producing high-quality BOPP film.

Determination of molecular weight and molecular sizes of polymers by high temperature gel permeation chromatography with a static and dynamic laser light scattering detector

Flow-mode static and dynamic laser light scattering (SLS/DLS) studies of polymers, including polystyrene, polyethylene, polypropylene and poly(dimethylsiloxane) (PDMS), in 1,2,4-trichlorobenzene (TCB) at 150 degreesC were performed on a high temperature gel permeation chromatography (GPC) coupled with a SLS/DLS detector. Both absolute molecular weight (M) and molecular sizes (radius of gyration, R-g and hydrodynamic radius, R-h) of polymers eluting from the GPC columns were obtained simultaneously. The conformation of different polymers in TCB at 150 degreesC were discussed according to the scaling relationships between R-g, R-h and M and the rho-ratio (p = R-g/R-h). Flow-mode DLS results of PDMS were verified by batch-mode DLS study of the same sample. The presented technique was proved to be a convenient and quick method to study the shape and conformation of polymers in solution at high temperature. However, the flow-mode DLS was only applicable for high molecular weight polymers with a higher refractive index increment such as PDMS.

The relation between formal potential and structure of indophenols and molecular mechnism of electrooxidation

The molecular structural parameters of indophenol and its derivatives were calculated by semi-empirical molecular orbital quantum chemical method,The relation between molecular structural parameters and formal potentials was analyzed by principal factor analysis and multiple Linear regression method. It was found that the formal potential of indophenols has a good relation with two-center electron exchange energy, E-ex (2), resonance energy of O-C bond, E-ex (C-1-O), and molecular ionization potential, I-p, among 19 moleclular structural parameters. The regression equation is E-0' = 1. 47 x 10 (-3) E-ex (two) - 5. 74 x 10 (-2) E-ex (C-1 - O) - 1. 41 x 10 (-2) I-p with RC = 0. 9999 and SD = 0. 00424. It was confirmed by the relation between structure parameters and formal potentials, and the thermodynamic stability of its intermediate products that the H (+) ionization is prior to the electron transfer step in the oxidation mechanism.

The past, present and future of phycology in China

Algae have been part of Chinese life for thousands of years. They are widely used as food and have been cited in Chinese literature as early as 2500 years ago. However, formal taxonomic studies on Chinese algae were initiated by foreign scientists only about 200 years ago, and by Chinese phycologists only about 90 years ago. This paper summarizes the history of modern phycological studies on Chinese algae and provides an overview of the achievements of phycological studies by Chinese scientists, especially on algal taxonomy, morphology, genetics, ecology and environmental research, physiology, biotechnology, algal culture, applied phycology and space phycology, in the last century. Recent development in phycological research focuses on algal floristic and molecular systematics, algal molecular biotechnology, applied phycology including micro and macroalgal cultivation and algal product development, and the roles of algae in environmental pollution control. These areas will also be the main focuses of Chinese phycological research in the foreseeable future.

Preparation of the different derivatives of the low-molecular-weight porphyran from Porphyra haitanensis and their antioxidant activities in vitro

Porphyran extracted from Porphyra haitanensis is a sulfated polysaccharide, which possesses excellent antioxidant activities. In this study, we prepared one low-molecular-weight porphyran and its sulfated, acetylated, phosphorylated and benzoylated derivatives. Their antioxidant activities were investigated including scavenging effect of superoxide, hydroxyl and 1,1-diphenyl-2-picrylhydrazyl radicals. The results of chemical analysis and FT-IR spectrums showed the modification was successful. And in addition, we found that certain derivative exhibited stronger antioxidant activity than low-molecular-weight porphyran. The benzoylated derivative showed the most excellent antioxidant activity in three assays, so this derivative needs to be attended to. (C) 2009 Elsevier B.V. All rights reserved.

Aqueous solutions of HEC and hmHEC: effects of molecular mass versus hydrophobic associations on hydrodynamic and thermodynamic parameters.

Aqueous solutions of amphiphilic polymers usually comprise of inter- and intramolecular associations of hydrophobic groups often leading to a formation of a rheologically significant reversible network at low concentrations that can be identified using techniques such as static light scattering and rheometry. However, in most studies published till date comparing water soluble polymers with their respective amphiphilic derivatives, it has been very difficult to distinguish between the effects of molecular mass versus hydrophobic associations on hydrodynamic (intrinsic viscosity [g]) and thermodynamic parameters (second virial coefficient A2), owing to the differences between their degrees of polymerization. This study focuses on the dilute and semi-dilute solutions of hydroxyethyl cellulose (HEC) and its amphiphilic derivatives (hmHEC) of the same molecular mass, along with other samples having a different molecular mass using capillary viscometry, rheometry and static light scattering. The weight average molecular masses (MW) and their distributions for the nonassociative HEC were determined using size exclusion chromatography. Various empirical approaches developed by past authors to determine [g] from dilute solution viscometry data have been discussed. hmHEC with a sufficiently high degree of hydrophobic modification was found to be forming a rheologically significant network in dilute solutions at very low concentrations as opposed to the hmHEC with a much lower degree of hydrophobic modification which also enveloped the hydrophobic groups inside the supramolecular cluster as shown by their [g] and A2. The ratio A2MW/[g], which takes into account hydrodynamic as well as thermodynamic parameters, was observed to be less for associative polymers compared to that of the non-associative polymers.

The Physical and Chemical Structure of Hot Molecular Cores

We have made self-consistent models of the density and temperature profiles of the gas and dust surrounding embedded luminous objects using a detailed radiative transfer model together with observations of the spectral energy distribution of hot molecular cores. Using these profiles we have investigated the hot core chemistry which results when grain mantles are evaporated, taking into account the different binding energies of the mantle molecules, as well a model in which we assume that all molecules are embedded in water ice and have a common binding energy. We find that most of the resulting column densities are consistent with those observed toward the hot core G34.3+0.15 at a time around 10^4 years after central luminous star formation. We have also investigated the dependence of the chemical structure on the density profile which suggests an observational possibility of constraining density profiles from determination of the source sizes of line emission from desorbed molecules.