Design ofVibrio 16S rRNA gene specific primers and their application in the analysis of seawaterVibrio community

The pathogenic species of genus Vibrio cause vibriosis, one of the most prevalent diseases of maricultured animals and seafood consumers. Monitoring their kinetics in the chain of seafood production, processing and consumption is of great importance for food and mariculture safety. In order to enrich Vibrio-representing 16S ribosomal RNA gene （rDNA） fragments and identify these bacteria further real-timely and synchronously among bacterial flora in the chain, a pair of primers that selectively amplify Vibrio 16S rDNA fragments were designed with their specificities and coverage testified in the analysis of seawater Vibrio community. The specificities and coverage of two primers, VF169 and VR744, were determined theoretically among bacterial 16S rDNAs available in GenBank by using BLAST program and practically by amplifying Vibrio 16S rDNA fragments from seawater DNA. More than 88.3% of sequences in GenBank, which showed identical matches with VR744, belong to Vibrio genus. A total of 33 clones were randomly selected and sequenced. All of the sequences showed their highest similarities to and clustered around those of diverse known Vibrio species. The primers designed are capable of retrieving a wide range of Vibrio 16S rDNA fragments specifically among bacterial flora in seawater, the most important natural environment of seafood cultivation.     

Development of a real-time PCR method (Taqman) for rapid identification and quantification of Prorocentrum donghaiense

Prorocentrum donghaiense is a dinoflagellate that is widely distributed in the East China Sea and has become increasingly involved in Harmful Algal Blooms (HABs). Therefore, it is necessary to study this dinoflagellate to monitor HABs. In this study, 13 pairs of primers specific to P. donghaiense (within its internal transcribed spacer (ITS) regions) were designed for SYBR Green I real-time PCR. As the SYBR Green I real-time PCR could not identify P. donghaiense in a specific manner, a Taqman real-time PCR method was developed by designing a set of specific primers and a Taqman probe. A 10-fold serial dilution of recombinant plasmid containing ITS regions of P. donghaiense was prepared as standard samples and the standard curve was established. Additionally, we quantified the genomic DNA in P. donghaiense cells and utilized this DNA to prepare another 10-fold serial dilution of standard sample and accordingly set up the standard curve. The mathematic correlation between the cell number and its corresponding plasmid copy number was also established. In order to test the efficiency of the real-time PCR method, laboratory samples and P. donghaiense HAB field samples were employed for identification and quantitative analysis. As to laboratory samples, as few as 102 cells of P. donghaiense could be quantified precisely utilizing both centrifugation and filtration techniques. The quantification results from field samples by real-time PCR were highly similar to those by light microscopy. In conclusion, the real-time PCR could be applied to identify and quantify P. donghaiense in HABs.     

Geochemistry of cryoconite and soils in the Central Caucasus region and its environmental implications

Climate change and deglaciation are active processes in current changing environments.In the Central Caucasus region rapid degradation of glaciers is caused oft...     

Development of Three Multiplex PCR Primer Sets for Ark Shell(Scapharca broughtonii) and Their Validation in Parentage Assignment

Scapharca broughtonii is a commercially important and over-exploited species.In order to investigate its genetic diversity and population structure,43 novel polymorphic microsatellites were isolated and characterized.The number of alleles per locus ranged from 3 to 22 with an average of 6.93,and the observed and expected heterozygosities varied between 0.233 and 1.000,and 0.250 and 0.953,with an average of 0.614 and 0.707,respectively.Three highly informative multiplex PCRs were developed from nine of those microsatellites for S.broughtonii.We evaluated and validated these multiplex PCRs in 8 full-sib families.The average polymorphism information content(PIC) was 0.539.The frequency of null alleles was estimated as 3.13% of all the alleles segregation based on a within-family analysis of Mendelian segregation patterns.Parentage analysis of real offspring demonstrated that 100% of all offspring were unambiguously allocated to a pair of parents based on 3 multiplex sets.Those 43 microsatellite loci with high variability will be helpful for the analysis of population genetics and conservation of wild stock of S.broughtonii.The 3 sets of multiplex PCRs could be an important tool of pedigree reconstruction,population genetic analysis and brood stock management.     

Paleosols and their reflection of the environmental changes in the northeast region of the Qinghai-Xizang Plateau

Based on field investigations, laboratory analyses and ¹⁴C dating, this paper discusses the laws of the formation and development of the paleosols in the northeast region of the Qinghai-Xizang Plateau since Late Pleistocene. The authors reconstruct basic conditions of climate, vegetation, soil and natural zones during the three periods in which the paleosols were formed, i.e. the last interglacial of the Late Pleistocene, warm stage of Late Glacial and the Optimum of Holocene. Finally, this paper discusses the relationship between the paleosols and the uplift of the Qinghai-Xizang Plateau.     

Diversity of oligotrich ciliates (Ciliophora,Spirotrichea) in the northern coast of South China Sea as revealed in LSU rDNA sequences

Journal of Oceanology and Limnology - Although the taxonomy of oligotrich ciliates has been widely investigated, yet the species diversity remains poorly known. We newly designed a pair of...     

Development of Genomic Microsatellite Multiplex PCR Using Dye-Labeled Universal Primer and Its Validation in Pedigree Analysis of Pacific Oyster(Crassostrea gigas)

There is an increasing requirement for traceability of aquaculture products, both for consumer protection and for food safety. There are high error rates in the conventional traceability systems depending on physical labels. Genetic traceability technique depending on DNA-based tracking system can overcome this problem. Genealogy information is essential for genetic traceability, and microsatellite DNA marker is a good choice for pedigree analysis. As increasing genotyping throughput of microsatellites, microsatellite multiplex PCR has become a fast and cost-effective technique. As a commercially important cultured aquatic species, Pacific oyster Crassostrea gigas has the highest global production. The objective of this study was to develop microsatellite multiplex PCR panels with dye-labeled universal primer for pedigree analysis in C. gigas, and these multiplex PCRs were validated using 12 full-sib families with known pedigrees. Here we developed six informative multiplex PCRs using 18 genomic microsatellites in C. gigas. Each multiplex panel contained a single universal primer M13(-21) used as a tail on each locus-specific forward primer and a single universal primer M13(-21) labeled with fluorophores. The polymorphisms of the markers were moderate, with an average of 10.3 alleles per locus and average polymorphic information content of 0.740. The observed heterozygosity per locus ranged from 0.492 to 0.822. Cervus simulations revealed that the six panels would still be of great value when massive families were analysed. Pedigree analysis of real offspring demonstrated that 100% of the offspring were unambiguously allocated to their parents when two multiplex PCRs were used. The six sets of multiplex PCRs can be an important tool for tracing cultured individuals, population genetic analysis, and selective breeding program in C. gigas.     

Complementary DNA sequencing (cDNA): an effective approach for assessing the diversity and distribution of marine benthic ciliates along hydrographic gradients

The Yellow Sea Cold Water Mass(YSCWM) is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobentho s diffe rs inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobentho s,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at five stations along hydrographic gradients across the YSCWM and adj acent shallow water by using morphology and DNA and complementary DNA(cDNA) high-throughput sequencing of the V4 region of 18 S rRNA gene.Results showed that the diversity of benthic ciliate s detected by DNA(303 OTU s),and the cDNA(611 OTUs) sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly different ciliate communities inside and outside of the YSCWM,but without statistical significance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all) of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly influenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have significant effects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments.     

A Kinetic Spectrophotometric Method for the Determination of Iron （Ⅲ） in Water Samples

A new kinetic spectrophotometric method has been developed for the determination of iron (Ⅲ). The method is based on the catalytic effect of iron (Ⅲ) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium. The advantages of the proposed method are that it is sensitive, accurate, rapid, inexpensive, can be operated under room temperature and has a large determination concentration range compared to other techniques. The obtained optimum conditions are pH 3.15, RAWL (200 mgL-1) 5.00mL, Potassium periodate solution (0.01 molL-1) 0.30mL, phenanthroline (0.02molL-1) 1.00mL, reaction temperature 25℃ and reaction time 7 miu. With this method iron could quantitively be determined in the range 0.00-0.02 mgL-1, the detection limit being 4.10×10-10mL-1. The relative standard deviations (RSD) in five replicate determinations for 3 μgL-1 and 5μgL-1 iron (Ⅲ) are 3.1% and 1.9%, respectively. The method has been applied to the determination of iron (Ⅲ) in tap water samples and seawater samples (from the South China Sea), the recovery rates being 98.0% and 100.5%, respectively.     

Development of a real-time PCR assay (SYBR Green I) for rapid identification and quantification of scyphomedusae Aurelia sp.1 planulae

The complicated life cycle of A urelia spp., comprising benthic asexually-reproducing polyps and sexually-reproducing medusae, makes it hard for researchers to identify and track them, especially for early stage individuals, such as planulae. To solve this problem, we developed a real-time PCR assay(SYBR Green I) to identify planulae in both cultured and natural seawater samples. Species-specific primers targeting Aurelia sp.1 mitochondrial 16 SrDNA(mt 16 SrDNA) regions were designed. Using a calibration curve constructed with plasmids containing the A urelia sp.1 mt 16 SrDNA fragment and a standard curve for planulae, the absolute number of mt 16 SrDNA copies per planula was determined and from that the total number of planulae per sample was estimated. For the field samples, a 100-fold dilution of the sample DNA combined with a final concentration of 0.2 μg/μL BSA in the PCR reaction mixture was used to remove realtime PCR inhibitors. Samples collected in Jiaozhou Bay from July to September 2012 were subsequently analyzed using this assay. Peak A urelia sp.1 planula abundance occurred in July 2012 at stations near Hongdao Island and Qingdao offshore; abundances were very low in August and September. The real-time PCR assay(SYBR Green I) developed here negates the need for traditional microscopic identification, which is laborious and time-consuming, and can detect and quantify jellyfish planulae in field plankton samples rapidly and specifically.     

Vertical patterns in plant diversity and their relations with environmental factors on the southern slope of the Tianshan Mountains (middle section) in Xinjiang (China)

The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis(DCCA) and the generalized additive model(GAM) methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe(2,200–2,300m), and in the alpine grassland region(2,900–3,100m), while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soil water, total nitrogen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.     

Environmental features and water environmental problems in the contiguous region of Jiangsu, Shangdong, Henan and Anhui Provinces

ThecontiguousregionofJiangsu,Shandong,HenanandAnhuiprovinces,withapopulationof4660X10'in1990,stretchingalongtheChina'seasternsectionofeconomicbeltofnewEurasialxindBridge,issituatedinthenortheasternpartoftheHuaiheRiverBasin,covering7.73X10'km'ofnineprefecturesormunicipalities,i.e.,XuzhouandLianyungangofJiangsuProvince,Rizhao,Linyi,ZaozhuangandJiningofShandongProvince,ShangqiuofHenanProvince,HuaibeiandSuxianofAnhuiProvince.Theregionisatraditionalagricultureareaandanimportantenergybase…     

Development strategies of water and land resources in the hexi region,China

Hexi region is located in the northwest arid zone in China, being both the base of industry and agriculture, and the prop of developing northwestern China on a large scale in the next century. On the basis of the study on exploitation and utilization process of water and land resources in past 40 years, and present productivity, this paper approaches the utilization trend and development potential of water and land resources; analyses the characteristics, problems and directions of resource utilization in the future; and proposes the countermeasures of rational development of water and land resources.     

HPAM和疏水缔合聚合物溶液在孤东七区油藏中适应性评价

为了解决孤东七区油藏聚合物溶液流变性与注入性的矛盾,筛选适宜非均质强、储层结构疏松等油藏条件的聚合物,在不同长度岩心中开展聚合物溶液渗流实验.在同一岩心上分段测压,建立聚合物溶液注入性评价方法,对HPAM和疏水缔合聚合物的注入性进行评价;在不同长度岩心出口端取采出液,研究该聚合物溶液在近井和油藏深部阻力因数、残余阻力因数以及黏度分布特性.结果表明:注入HJ的压力梯度上升率为16.37MPa.m-1.PV-1,压力梯度稳定值为5.68MPa.m-1,压力梯度上升率和压力梯度稳定值小于相同质量浓度的DH5和B4的值;从提高波及效率的能力和聚合物溶液的流变性来看,疏水缔合聚合物DH5在油藏深部的阻力因数、残余阻力因数和黏度保留率分别为283.86、39.4和0.713,阻力因数、残余阻力因数远大于相同质量浓度的B4和HJ的值;综合注入性和流变性分布评价可知,1.8g.L-1的HJ好于相同质量浓度的DH5和B4的.     

Vegetation diversity along the altitudinal and environmental gradients in the main wadi beds in the mountainous region of South Sinai,Egypt

South Sinai includes Egypt's highest mountains that resemble an ecological island surrounded by desert. The present study aims to analyse the vegetation physiognomy along the altitudinal and environmental gradients in the main wadi beds in South Sinai mountainous region. This includes determining the natural, native-weed and alien vegetation in representative stands in this region, analysing their vegetation in terms of species composition, abundance and life forms and determining the national and global distribution of the associated species. This investigation also aims to describe the prevailing plant communities and assess the role of environmental conditions that affect the vegetation in this region. Thus, thirty-two stands were chosen during March-June 2018 to reflect the prevailing altitude and environmental gradients. Total species was 316(229 genera and 61 families): 186 species were perennials(58.9%), while 130 were annuals(41.1%). In addition, 152 species were native weeds(48.1% of total species), 31 were aliens(9.8%), along with 133 natural species(42.1%). Eight species were recorded as endemic to Egypt: Anarrhinum pubescens, Euphorbia sanctae-catharinae, Hypericum sinaicum, Origanum syriacum subsp. sinaicum, Phlomis aurea, Primula boveana, Rosa arabica and Solanum sinaicum. In addition, 10 species were recorded as near-endemics to Egypt and other adjacent countries: Allium desertorum, Asclepias sinaica, Centaurea scoparia, Fagonia mollis var. hispida, Hyoscyamus boveanus, Iphiona mucronata, Micromeria sinaica, Pterocephalus sanctus, Salvia deserti and Stachys aegyptiaca. In the present study, 33 species are threatened and categorized as follows: 8 endangered, 8 vulnerable and one indeterminate, while the rest were evaluated by the authors as rares. The rich plant diversity of this region is due to its extensive mountainous massif, which supports many microhabitats. The high elevations in this region hinder the dispersal process of propagules, a situation which often tends to increase endemic and near-endemic species. The current results were discussed and compared with some related previous studies.     

Age and growth of chub mackerel (Xcomber japonicus) in the East China and Yellow Seas using sectioned otolith samples

Although chub mackerel (Scomber japonicus) is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion (AIC), the von Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.     

Neotectonics of the Avaj region(NW Iran): left-lateral strike-slip and range-parallel reverse faults

The aim of this study is the geomorphological analysis of neotectonic deformation in the Avaj region in the NW part of the Iranian Plateau. We use observations from detailed field surveys and the analysis of digital elevation model(DEM) and satellite images(Landsat-7 ETM+, 30-m resolution) to explore a new E-W trending strike-slip fault system in the study area. The major active faults of the Avaj region are the NW-SE trending Avaj and Hassanabad fault zones. The Avaj Fault is a SWdipping reverse fault with a transport toward NE and the Hassanabad Fault is a NE-dipping reverse fault that has moved Paleozoic rocks over Cenozoic sedimentary units. Moreover, there are some E-W trending left-lateral strike-slip faults which cut Late Quaternary deposits. The relationship between the NW-SE and E-W faults indicates that the slip at the termination of the NW-SE faults changes from reverse to left-lateral strike-slip faults. The activity of the left-lateral faults has formed a series of offsets and displacements in drainage paths. These left-lateral faults probably initiated in 5±2 Ma because of the convergence between the Central Iran and the South Caspian blocks.     

Spatial differentiation in stable isotope compositions of surface waters and its environmental significance in the Issyk-Kul Lake region of Central Asia

Stable isotope values of oxygen(~(18)O) and hydrogen(~(2)H) of surface waters were used to study the origin and environmental significances in the Issyk-Kul basin of Kyrgyzstan in Central Asia, which is the most important intermountain basin in the modern Tien Shan orogen. This study is the first analysis of hydrochemical spatial differentiation in the stable isotopes of surface waters in this watershed.75 samples were collected from rivers, springs, lakes,rain and snow during the rainy season in July and August of 2016. Stable isotopes of ~(18)O and ~(2)H were studied for all samples, and cation ratios(Sr/Ca and Mg/Ca) were also determined for lake water samples.Stable isotope values from precipitation scattered around the Local Meteoric Water Line(determined from Urumqi Station of the global network of isotopes in precipitation(GNIP)), together with values of the Deuterium excess parameter(d) from 15.3‰ to30.5‰, with an average of 19.8‰, indicating that the moisture sources are primarily from regions with low relative humidity. The δ~(18)O and δ~(2)H values were significantly different between the river and lake samples, indicating that regional evaporation caused the isotopic enrichment of lake water. Geospatial autocorrelation, measured by Moran's I coefficient,indicated weak spatial autocorrelation within stable isotopes of oxygen and hydrogen in the surface waters of the studied area, which is primarily an effect of climate during the water chemistry evolution. The cation ratios Sr/Ca and Mg/Ca in lake water samples were not correlated with the concentration of total dissolved solids, but did show correlation with stable isotopic values, which is significant for paleoenvironmental reconstruction.     

Aquatic molluscs in high mountain lakes of the Eastern Alps (Austria): Species-environment relationships and specific colonization behaviour

Mountain lakes represent essential stages for aquatic species on their way colonizing habitats of more elevated regions. Despite extensive biological and chemical study, only little has been reported about the species number and density of freshwater molluscs in these waters. The article presented here elucidates the dispersal of aquatic gastropods and bivalves in 12 mountain lakes that are commonly situated in the Eastern Alps, Austria. Molluscs were recorded at 120 sample points, where a total of 13 species (8 gastropods and 5 bivalves) could be determined. Species distribution data as well as results from contemporarily conducted physico-chemical factor recording were subject to weighted average analysis. In addition, a global marginality coefficient indicating the particularity of a habitat inhabited by a focal species as well as a global tolerance coefficient expressing the width of a niche occupied by this species were computed. Species-environment relationships exhibited that species number and specific density decrease with increasing geographic altitude, declining water temperature, and decreasing amount of submerged vegetation. Whilst waters of the montane altitude level are partly charcterized by high number of mollusc species (> 10), lakes of the subalpine altitude level commonly bear 1 or 2 species with <<1 ind./m2. As proposed by the results of statistics, 9 of the 13 mollusc species are characterized by a pronounced behaviour as specialists with respect to most environmental factors. The four remaining species, Pisidium casertanum, Galba truncatula, Radix labiata, and Radix balthica, act as generalists which increases their pioneering role in the long-term occupation of the Central-alpine region.     

Long-term changes in sedimentary diatom assemblages and their environmental implications in the Changjiang (Yangtze) River estuary,China

Long-term data on diatom assemblages in a sediment core （60 cm） obtained from the Changjiang （Yangtze） River estuary were analyzed in order to assess the environmental changes that took place in the approximately 38 years （as determined by 210pb measurements）, i.e., between 1974 and 2012, of sediment accumulation. From the sediment core, 62 diatom taxa and genera were identified. The diatom biomass in the core generally increased beginning in the mid-1990s （core depth： 35 cm）, accompanied by a shift in the dominant species from Podosira stelliger and two species of Cyclotella （C. stylorum and C. striata） to Paralia sulcata, three species of Thalassiosira （ T. eccentria, I＂. oestrupii, and T. excentrica）, Actinoptychus undulates, and Thalassionema nitzschioides. The changes in both species diversity and abundance suggested that since the 1980s the estuary has undergone extensive eutrophication. This conclusion was supported by the increased proportion of planktonic species, another indicator of high nutrients inputs, in the Changjiang River estuary.