17种金线鲃核DNA含量及倍性的研究

采用血涂片、Feulgen染色和显微分光光度技术 ,测定了金线属 (Sinocyclocheilus) 17个种的核DNA含量。结果显示 ,除侧条金线 (S .lateristritus)中采自云南沾益炎方山那边的样本之 2C值为 7 79pg外 ,其余的核DNA 2C值都集中分布在 4 19～ 4 86pg范围 ,大体与其近缘四倍体种 2C值相同或相近 ,是其近缘二倍体种 2C值的大约 2倍。据此我们推断 ,这 17种金线很可能都是四倍体 ,个别种还含有八倍体的类型 ,金线属可能是整属的四倍体起源。     

DNA Barcoding for Species Assignment: The Case of Mediterranean Marine Fishes

Background

DNA barcoding enhances the prospects for species-level identifications globally using a standardized and authenticated DNA-based approach. Reference libraries comprising validated DNA barcodes (COI) constitute robust datasets for testing query sequences, providing considerable utility to identify marine fish and other organisms. Here we test the feasibility of using DNA barcoding to assign species to tissue samples from fish collected in the central Mediterranean Sea, a major contributor to the European marine ichthyofaunal diversity.

Methodology/Principal Findings

A dataset of 1278 DNA barcodes, representing 218 marine fish species, was used to test the utility of DNA barcodes to assign species from query sequences. We tested query sequences against 1) a reference library of ranked DNA barcodes from the neighbouring North East Atlantic, and 2) the public databases BOLD and GenBank. In the first case, a reference library comprising DNA barcodes with reliability grades for 146 fish species was used as diagnostic dataset to screen 486 query DNA sequences from fish specimens collected in the central basin of the Mediterranean Sea. Of all query sequences suitable for comparisons 98% were unambiguously confirmed through complete match with reference DNA barcodes. In the second case, it was possible to assign species to 83% (BOLD-IDS) and 72% (GenBank) of the sequences from the Mediterranean. Relatively high intraspecific genetic distances were found in 7 species (2.2%–18.74%), most of them of high commercial relevance, suggesting possible cryptic species.

Conclusion/Significance

We emphasize the discriminatory power of COI barcodes and their application to cases requiring species level resolution starting from query sequences. Results highlight the value of public reference libraries of reliability grade-annotated DNA barcodes, to identify species from different geographical origins. The ability to assign species with high precision from DNA samples of disparate quality and origin has major utility in several fields, from fisheries and conservation programs to control of fish products authenticity.     

Geochemical associations,risk assessment,and source identification of selected metals in sediments from the Suez Gulf,Egypt

Sequential extraction procedure has been carried out to scrutinize the geochemical association of Cadmium (Cd), Copper (Cu), Iron (Fe), Lead (Pb), and Manganese (Mn) with the main sedimentary phases (exchangeable, carbonate, Fe-Mn oxides, organic, and residual fraction) at 10 marine sediment samples collected from the Suez Gulf. Global contamination factor was used to identify the pollution hotspots, which indicated the existence of intensive metal contamination at stations close to the northern part of the Gulf, especially for Cd, Cu, and Pb. The potential ecological risk indices: Potential ecological risk index, risk assessment code, and modified risk assessment code revealed that there are potential hazards to marine biota caused by Cd, Cu, and Pb due to the increased levels of these metals in the labile fractions, which are vulnerable to changes in environmental conditions. This work is a good basis for further studies about metal fractionation in the Suez Gulf. It is also very helpful for government decisions about the development of the Gulf.     

Changes of palaeozonation patterns within Miocene coral reefs, Gebel Abu Shaar, Gulf of Suez, Egypt

The Gebel Abu Shaar represents the southern end of a tilted fault-block consisting of Precambrian basement upon which a mixed siliciclastic-carbonate platform developed during mid-Miocene time. The Miocene sequence contains coral reefs and reef facies. Palaeozonation patterns of the Miocene coral reefs were assessed on the well-preserved outcrops of the Gebel Abu Shaar by recording both qualitative and quantitative data of reef-building assemblages. The various patterns of palaeozonation were analysed and compared at different spatial and temporal scales, including both within-reef and between-reef variations. The palaeozonal changes recorded within these fossil reefs are similar to those described from present-day living coral reefs and involve contraction or extension, fusion or splitting, replacement and omission of reef-builder zones. Depending on the scale concerned, the nature and importance of changes affecting the palaeozonation pattern vary. Spatial variations of the palaeozonal pattern appear mainly controlled by local changes of ecological conditions while temporal variations are related to regional and global environmental changes.     

Assessing Genetic Diversity of Brazilian Reef Fishes by Chromosomal and DNA Markers

Little is known on genetics of Brazilian coral reef fish and most of this information is limited to chromosome characterization of major representative species. The diploid chromosome number in marine fish varies from 2n= 22–26 to 2n = 240–260. Despite of this apparent diversity, most studied marine species have a diploid complement with 48 acrocentric chromosomes. This latter trend is mostly observed among Perciformes, an important major taxon of coral reef fishes. Studies in the families Pomacentridae, Pomacanthidae and Chaetodontidae, for example, have shown a common karyotype pattern entirely formed by 48 uniarmed chromosomes. However, rare numerical and structural chromosome polymorphisms and cryptic chromosome rearrangements involving heterochromatin segments and/or nucleolar organizing sites have been reported among such fishes. Although new chromosome forms can contribute to the establishment of genetically isolated populations, their role in reef fish speciation at marine realm still is an open question. More recently, genomic DNA analyses using RAPD and microsatellites, and sequencing and RFLP of mitochondrial DNA have increasingly been used in Atlantic reef fish species. Genetic homogeneity over wide geographical ranges has been reported for different fish groups, in contrast to several cases of population substructuring related to environmental constraints or evolutionary history. Amazonas outflow and upwelling on the Southeastern coast of Brazil are believed to be strong barriers to dispersal of some reef species. Moreover, it is suggested that the pattern of speciation and population structure at South Atlantic is quite distinctive from Pacific Ocean, even when comparing closely related taxa. Further genetic studies are strongly encouraged in Brazilian reef fishes in order to provide a reliable scenario of the genetic structure in this important and diverse fish group.     

Plankton stratigraphy of the Early and Middle Miocene Kareem and Rudeis Formations in the central part of the Gulf of Suez,Egypt

The planktonic foraminifera and nannofossils of three wells in the Gulf of Suez penetrating the Early to Middle Miocene Upper Rudeis and Kareem Formations are attributed (from top to base) to the Middle Miocene Globorotalia peripheroronda Partial Range Zone (M6), the earliest Middle Miocene Praeorbulina sicana–Orbulina suturalis Interval Zone (M5), subdivided into the Praeorbulina glomerosa s. strict.–O. suturalis Interval Subzone (M5b) and the P. sicana–P. glomerosa s. str. Interval Subzone (M5a) and the Early Miocene Globigerinoides bisphericus Partial Range Subzone (M4b). The appearance of O. suturalis at the base of Subzone M5b represents the final stage of evolution of the Globigerinoides trilobus–Praeorbulina–Orbulina Lineage. In addition, the calcareous nannoplankton assemblages indicate the Sphenolithus heteromorphus Zone (NN5) and the Helicosphaera ampliaperta Zone (NN4). These biozones are well correlatable with those established by El-Heiny and Martini (1981, Geol Mediterr. Tome, VIII(2): 101–108) from the southwestern flank of the Gulf of Suez.     

Diversity and Evolution of Body Size in Fishes

The diversity of body sizes observed among species of a clade is a combined result of microevolutionary processes (i.e. natural selection and genetic drift) that cause size changes within phylogenetic lineages, and macroevolutionary processes (i.e. speciation and extinction) that affect net rates of diversification among lineages. Here we assess trends of size diversity and evolution in fishes (non-tetrapod craniates), employing paleontological, macroecological, and phylogenetic information. Fishes are well suited to studies of size diversity and evolution, as they are highly diverse, representing more than 50% of all living vertebrate species, and many fish taxa are well represented in the fossil record from throughout the Phanerozoic. Further, the frequency distributions of sizes among fish lineages resemble those of most other animal taxa, in being right-skewed, even on a log scale. Using an approach that measures rates of size evolution (in darwins) within a formal phylogenetic framework, we interpret the shape of size distributions as a balance between the competing forces of diversification, pushing taxa away from ancestral values, and of conservation, drawing taxa closer to a central tendency. Within this context we show how non-directional mechanisms of evolution (i.e. passive diffusion processes) can produce an hitherto unperceived bias to larger size, when size is measured on the conventional log scale. These results demonstrate how the interpretation of macroecological datasets can be enriched from an historical perspective, and document the ways in which macroevolutionary and microevolutionary processes may be decoupled in the production of size diversity.     

An Ornithological Trip in the Gulf of Suez and Red Sea.

From what I personally observed on this trip and from information gathered en route and elsewhere, it would seem that-in spring at any rate-the migration along the Red Sea and Gulf of Suez is not very extensive, particularly with regard to the smaller birds. White Storks and Lesser Black-backed Gulls, however, follow this line in vast numbers on their journey north, though, as regards the first-named species, the vast majority had passed through earlier than the date of my visit to that district.
As will be noted from the list of species appended to this paper, very little collecting was done with the gun. The principal object of the trip was to obtain live specimens of the Osprey and other of the larger birds breeding in the locality for the Giza Zoological Gardens. In respect of the Osprey only was I successful, and returned with three young which were still flourishing in the Zoo collection when I left Egypt in July 1927. I was disappointed in not finding more species engaged in nesting operations, and it would appear that such birds as Sula leuco- gaster , Phaëton indicus , Casmerodius albus melanorhynchus , Platalea leucorodia , Larus leucophthalmus , and Sterna bergii welox , which undoubtedly breed in the latitude I visited, do so considerably later in the year than the month of April. Further south, on the Farsan Group of Islands Lat. N. 17°, the Brown Booby was breeding in October. Eggs were found at the end of that month and young birds early in November 1926.     

鲀形目3种鱼的染色体组型分析

采用胸腔注射植物血球凝集素(phytohemagglutinin,PHA)及秋水仙素溶液,取活体头肾细胞经低渗、固定、空气干燥法,分析比较了中华单角鲀(Monacanthus chinensis)、黄鳍东方鲀(Takifuguxanthopterus)、红鳍东方鲀(T.rubripes)的核型。结果表明,3种海水鱼中期染色体均为二倍体,未发现异型性染色体、随体和次缢痕。其核型如下:中华单角鲀的核型为2n=34(34t),臂数:NF=34;黄鳍东方鲀的核型为2n=44(12m+8sm+24t),臂数:NF=64;红鳍东方鲀的核型为2n=44(14m+6sm+24t),臂数:NF=64。中华单角鲀的核型与后两者存在较大差异。同时,将此3种鱼的核型与前人报道的其他鲀形目鱼类核型作了比较。     

邢台市及郊区鸟类区系组成及多样性

2003年3月~2005年7月对邢台市鸟类区系组成及多样性进行了调查,共记录到鸟类166种,隶属15目42科。本文重点探讨了不同生境、不同季节鸟类群落的种类、多样性、均匀度、相似性等群落特征。结果表明,鸟类种数由多至少依次为林地生境、公共绿地生境、河流水域生境、农田生境、建筑区生境。Shannon-Weiner多样性指数由大到小依次为林地生境、公共绿地生境、河流水域生境、农田生境、建筑区生境。比较这5种生境之间的相似性得出,公共绿地生境鸟类群落与建筑区生境鸟类群落、林地生境鸟类群落相似,相似性达到60%以上,而河流水域生境鸟类群落与其他生境鸟类群落有极明显的差异。     

Evolution and Phylogenetic Diversity of Yam Species (Dioscorea spp.): Implication for Conservation and Agricultural Practices

Yams (Dioscorea spp.) consist of approximately 600 species. Presently, these species are threatened by genetic erosion due to many factors such as pest attacks and farming practices. In parallel, complex taxonomic boundaries in this genus makes it more challenging to properly address the genetic diversity of yam and manage its germplasm. As a first step toward evaluating and preserving the genetic diversity yam species, we use a phylogenetic diversity (PD) approach that has the advantage to investigate phylogenetic relationships and test hypotheses of species monophyly while alleviating to the problem of ploidy variation within and among species. The Bayesian phylogenetic analysis of 62 accessions from 7 species from three regions of Cameroon showed that most Dioscorea sections were monophyletic, but species within sections were generally non-monophyletic. The wild species D. praehensilis and cultivated D. cayenensis were the species with the highest PD. At the opposite, D. esculenta has a low PD and future studies should focus on this species to properly address its conservation status. We also show that wild species show a stronger genetic structure than cultivated species, which potentially reflects the management of the yam germplasm by farmers. These findings show that phylogenetic diversity is a promising approach for an initial investigation of genetic diversity in a crop consisting of closely related species.     

Life history strategies of four small-size fishes in the Suez Canal, Egypt

Of 35 species collected from the shores of the Suez Canal and its lakes, five were abundant year round. Sihouettea aegyptia and Aphanius dispar are of Red Sea (warm water) origin, whereas Pomatoschistus marmoratus, Aphanius fasciatus and Atherina boyeri are Mediterranean species. S. aegyptia and A. dispar are distributed throughout the Suez system whereas A. fasciatus is restricted to the northern canal. P. marmoratus and A. boyeri have not spread southward beyond the Bitter Lakes. Salinity is the main limiting factor for the distribution of Mediterranean species. S. aegyptia and A. dispar are dominant in the Bitter Lakes (salinity 44‰), whereas P. marmoratus and A. boyeri are abundant in Timsah Lake (salinity 7·8–41·6‰). There was considerable interannual and monthly variation in the relative abundance of each species. The populations were dominated by a single age group, and life spans were no more than 2 years. Rapid growth was evident during the first spring in P. marmoratus and A. boyeri and during the first summer, early autumn in S. aegyptia and A. dispar . The relative abundance of each food item in the diet varied with fish size and season. S. aegyptia, P. marmoratus and A. dispar fed mostly on harpacticoid copepods, polychaetes, demersal eggs, diatoms and blue-green algae whereas A. boyeri fed mostly on planktonic copepods. The warm water species are summer spawners, whereas the temperate species are autumn-winter spawners.     

Integrated Taxonomy Reveals Hidden Diversity in Northern Australian Fishes: A New Species of Seamoth (Genus Pegasus)

Fishes are one of the most intensively studied marine taxonomic groups yet cryptic species are still being discovered. An integrated taxonomic approach is used herein to delineate and describe a new cryptic seamoth (genus Pegasus) from what was previously a wide-ranging species. Preliminary mitochondrial DNA barcoding indicated possible speciation in Pegasus volitans specimens collected in surveys of the Torres Strait and Great Barrier Reef off Queensland in Australia. Morphological and meristic investigations found key differences in a number of characters between P. volitans and the new species, P. tetrabelos. Further mt DNA barcoding of both the COI and the slower mutating 16S genes of additional specimens provided strong support for two separate species. Pegasus tetrabelos and P. volitans are sympatric in northern Australia and were frequently caught together in trawls at the same depths.     

First evidence of enterobiasis in ancient Egypt

The oldest and most common parasite for which we have direct evidence, in the New World, is Enterobius vernicularis. Numerous archaeological sites, especially in the arid American southwest, have yielded fecal samples positive for pinworm ova, some of these dating back 10,000 yr. Reports of pinworm from the Old World are scarce. This article reports the first evidence of pinworm infection from Roman-occupied (30 BC-AD 395) Egypt.     

Vascular Plant Species Inventory of a Philippine Lowland Rain Forest and its Conservation Value

The Philippines are one of the most important biodiveristy hotspots on earth. Due to the extraordinary rate of environmental destruction, leaving only 3% of the land with primary forest, this biodiversity is at high risk. Despite that situation information on Philippine forest vegetation is fragmentary and focused on trees. This study aimed at analysing forest remnants in the Leyte Cordillera on the Island of Leyte, and at evaluating their role as refuge to the largely destroyed lowland forest vegetation. A total of 49 plots (100 m² each) between 55 and 520 m a.s.l. were studied. All vascular plant species except epiphytes were included. Records include 685 taxa from 289 genera and 111 families, representing nearly 8% of the known Philippine vascular plant species. More than half (52%) of the species are Philippine endemics. A number of 41 tree species, or 6% of all taxa recorded, are included in the IUCN red list, either as vulnerable, endangered, or critically endangered. Life form composition was dominated by phanerophytes (65.3%), followed by lianas and chamaephytes (17.1 and 16.9%, respectively). The most common families were the Rubiaceae with 35 and the Euphorbiaceae with 32 species. All five Philippine dipterocarp forest types as well as the molave forest type were represented by typical tree species. The area provides an important gene bank of the highly threatened Philippine lowland forest vegetation and is of high value for biodiversity conservation. Additionally, it can play an important role as seed source of valuable tree species for the increasing initiatives to rehabilitate and reforest degraded land with native species.     

Plant Functional Diversity and Species Diversity in the Mongolian Steppe

Background

The Mongolian steppe is one of the most important grasslands in the world but suffers from aridization and damage from anthropogenic activities. Understanding structure and function of this community is important for the ecological conservation, but has seldom been investigated.

Methodology/Principal Findings

In this study, a total of 324 quadrats located on the three main types of Mongolian steppes were surveyed. Early-season perennial forbs (37% of total importance value), late-season annual forbs (33%) and late-season perennial forbs (44%) were dominant in meadow, typical and desert steppes, respectively. Species richness, diversity and plant functional type (PFT) richness decreased from the meadow, via typical to desert steppes, but evenness increased; PFT diversity in the desert and meadow steppes was higher than that in typical steppe. However, above-ground net primary productivity (ANPP) was far lower in desert steppe than in the other two steppes. In addition, the slope of the relationship between species richness and PFT richness increased from the meadow, via typical to desert steppes. Similarly, with an increase in species diversity, PFT diversity increased more quickly in both the desert and typical steppes than that in meadow steppe. Random resampling suggested that this coordination was partly due to a sampling effect of diversity.

Conclusions/Significance

These results indicate that desert steppe should be strictly protected because of its limited functional redundancy, which its ecological functioning is sensitive to species loss. In contrast, despite high potential forage production shared by the meadow and typical steppes, management of these two types of steppes should be different: meadow steppe should be preserved due to its higher conservation value characterized by more species redundancy and higher spatial heterogeneity, while typical steppe could be utilized moderately because its dominant grass genus Stipa is resistant to herbivory and drought.     

Alteration of Fish Diversity Downstream from Petit-Saut Dam in French Guiana. Implication of Ecological Strategies of Fish Species

Dams are expected to decrease fish diversity because they deeply alter downstream environment. However, such decline has not been consistently observed although profound modifications in the structure and/or composition of fish communities were generally recorded, and were linked to modifications of the downstream environment. In this work we analyze data from observations made before and almost 10 years after the completion of a hydroelectric dam in the neotropics. We monitored fish diversity below that dam and compared the taxonomic and functional structures of the samples between the pre- and post-dam periods. A significant decrease in species richness was evidenced. Taxonomic and trophic structures were significantly different between the two periods. Conversely, the functional structure of samples based on reproductive traits did not change significantly after the damming. Concerning feeding habits, a large increase in relative abundance of detritivores and a parallel decrease of fish species feeding on terrestrial food sources were observed in samples taken 6–9 years after closure of the dam as compared with samples taken before the dam.     

青海省6种裂腹鱼COI基因作为DNA条形码的适用性初探

青海省裂腹鱼鱼类至少有20种,占土著鱼类的40%以上,具有重要的生态价值。由于生态环境的恶化和人为因素的干扰,很多物种群已濒临灭绝。快速和准确的物种鉴定对于这些物种的保护至关重要,而基于形态学的传统分类法很难满足这一需求。因此,本研究通过DNA条形码技术初步探讨了在青海省裂腹鱼物种鉴定中的适用性。本研究中,测序获得了青海26尾裂腹鱼(6个物种)的细胞色素c氧化酶亚基I (COI)基因,并经GenBank数据库进行比对;基于K2P模型分析COI序列变异;运用贝叶斯法(BI)和最大似然法(ML)构建系统发育树。结果显示,6种裂腹鱼COI序列检测得到15个单倍型,且各物种间无共享的单倍型。基于K2P模型,最大种内遗传距离和最小种间遗传距离分别为(0.621±0.297)%和(2.792±0.644)%。种间平均遗传距离为(12.205±1.307)%,约为种内平均遗传距离((0.327±0.162)%)的37倍,表明各物种的COI序列间已经形成明显"条形码间隙"。AMOVA分析显示,遗传变异主要来自种间,约占97.05%;FST=0.970 54,p<0.01,说明各物种间分化程度极高。此外,基于BI和ML方法构建的系统树具有一致的拓扑结构,分辨率较高;各物种均单独聚为一个发育枝,拓扑结构合理。以上结果表明,COI基因作为DNA条形码在青海裂腹鱼物种鉴定中具有较高的适用性。     

Host Specificity of Pathogenic Pythium Species: Implications for Tree Species Diversity

In the Janzen–Connell hypothesis, host-specific natural enemies enhance species diversity and influence the structure of plant communities. This study tests the explicit assumption of host specificity for soil pathogens of the genus Pythium that cause damping-off disease of germinating seeds and seedlings. We isolated Pythium spp. from soil of a tropical forest in Panama. Then, in an inoculation experiment, we determined the pathogenicity of 75 tropical isolates of unknown pathogenicity and seven pathogenic temperate isolates of Pythium on seeds and/or seedlings of eight tropical tree species. Only three tropical isolates, one identified as P. ultimum and two as P. aphanidermatum , were pathogenic. Tropical pathogenic isolates were pathogenic on 4–6 of eight tree species. Temperate isolates were pathogenic on 0–4 of eight species, indicating that some tropical tree species are susceptible to novel isolates of Pythium . No tree species was susceptible to all isolates and two species were not susceptible to any isolate. Collectively, these results indicate that these Pythium isolates vary widely in their pathogenicity, causing differential mortality of potential host species; likewise, the tree species vary in their susceptibility to a given Pythium isolate. These differences in pathogenicity and susceptibility indicate some support for the Janzen–Connell assumption of host specificity. While they are not restricted to a single species, their intermediate level of specificity suggests that Pythium spp. have the potential to have some effect on forest community structure and diversity.