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High Diversity (high + diversity)
Selected AbstractsHigh Diversity on Simple Substrates: 1,4-Dihalo-2-butenes and Other Difunctionalized Allylic Halides for Copper-Catalyzed SN2, ReactionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2008Caroline A. Falciola Dr. Abstract Enantioselective allylic alkylation with an organomagnesium reagent catalyzed by copper thiophene carboxylate (CuTC) was carried out on difunctionalized substrates, such as commercially available 1,4-dichloro-2-butene and 1,4-dibromo-2-butene, and on similar compounds of higher substitution pattern of the olefin for the formation of all-carbon chiral quaternary centers. The high regioselectivity obtained throughout the reactions favored good regiocontrol for the addition of phenyl Grignard reagents. Other difunctionalized substrates (allylic ethers and allylic alcohols) also underwent asymmetric SN2, substitution. [source] GeoChip-based analysis of functional microbial communities during the reoxidation of a bioreduced uranium-contaminated aquiferENVIRONMENTAL MICROBIOLOGY, Issue 10 2009Joy D. Van Nostrand Summary A pilot-scale system was established for in situ biostimulation of U(VI) reduction by ethanol addition at the US Department of Energy's (DOE's) Field Research Center (Oak Ridge, TN). After achieving U(VI) reduction, stability of the bioreduced U(IV) was evaluated under conditions of (i) resting (no ethanol injection), (ii) reoxidation by introducing dissolved oxygen (DO), and (iii) reinjection of ethanol. GeoChip, a functional gene array with probes for N, S and C cycling, metal resistance and contaminant degradation genes, was used for monitoring groundwater microbial communities. High diversity of all major functional groups was observed during all experimental phases. The microbial community was extremely responsive to ethanol, showing a substantial change in community structure with increased gene number and diversity after ethanol injections resumed. While gene numbers showed considerable variations, the relative abundance (i.e. percentage of each gene category) of most gene groups changed little. During the reoxidation period, U(VI) increased, suggesting reoxidation of reduced U(IV). However, when introduction of DO was stopped, U(VI) reduction resumed and returned to pre-reoxidation levels. These findings suggest that the community in this system can be stimulated and that the ability to reduce U(VI) can be maintained by the addition of electron donors. This biostimulation approach may potentially offer an effective means for the bioremediation of U(VI)-contaminated sites. [source] High diversity of HHV-8 molecular subtypes in the Amazon region of Brazil: Evidence of an ancient human infection,JOURNAL OF MEDICAL VIROLOGY, Issue 10 2007Marluísa de Oliveira Guimarães Ishak Abstract The present study describes the molecular epidemiology of Human herpesvirus 8 (HHV-8) among four Indian tribes (Kararao, Arara Laranjal, Tiriyo, and Zo'e) of the Amazon region of Brazil and a group of HIV-1-infected subjects from the urban population of Belem, Para. Infection was characterized by the presence of antibodies using ELISA (measuring antibodies to ORF59, ORF65, K8.1A, K8.1B, and ORF73), and molecular assays (gene amplification of the regions ORF26 and the variable region VR1). Antibodies to HHV-8 were detected in 66 samples of the 221 Brazilian Amerindians, namely, 6 (25%) in the Kararao, 18 (19.6%) in the Arara Laranjal, 24 (42.9%) in the Tiriyo, and 18 (36.7%) in the Zo'e. Among the 477 HIV-1-infected subjects, antibodies to HHV-8 were present in 74 (15.5%) persons. The ORF26 region was amplified in seven samples, one of the Arara Laranjal, one of the Tiriyo, two of the Zo'e, and three of the HIV-1-infected group. Subtyping of HHV-8 described a high multiplicity of molecular subtypes, including C (Zo'e), E (Tiriyo), and B (HIV-1 infected). Serological results confirm the high prevalence of HHV-8 among Amerindians and the presence of three subtypes in the Amazon region of Brazil, including a unique subtype, which favors the idea of HHV-8 as an ancient human infection within this particular geographical region. J. Med. Virol. 79:1537,1544, 2007. © Wiley-Liss, Inc. [source] High diversity dinoflagellate cyst assemblages from the Late Triassic of southern England: new information on early dinoflagellate evolution and palaeogeographyLETHAIA, Issue 4 2006Raffaella Bucefalo Palliani Abundant and diverse dinoflagellate cyst assemblages from the Rhaetian of southern England are characterized by the occurrence of a new species of Rhaetogonyaulax, some undescribed taxa and numerous forms with Arctic and Australasian affinities. The dinoflagellate cyst assemblages permit a discussion of the palaeogeographic distribution of dinoflagellate cysts in the Late Triassic. The hypothesis on a Late Triassic migration event of organic walled microplankton from higher latitudes to the Boreal domain is presented. [source] Mitochondrial DNA reveals multiple Northern Hemisphere introductions of Caprella mutica (Crustacea, Amphipoda)MOLECULAR ECOLOGY, Issue 5 2008GAIL V. ASHTON Abstract Caprella mutica (Crustacea, Amphipoda) has been widely introduced to non-native regions in the last 40 years. Its native habitat is sub-boreal northeast Asia, but in the Northern Hemisphere, it is now found on both coasts of North America, and North Atlantic coastlines of Europe. Direct sequencing of mitochondrial DNA (cytochrome c oxidase subunit I gene) was used to compare genetic variation in native and non-native populations of C. mutica. These data were used to investigate the invasion history of C. mutica and to test potential source populations in Japan. High diversity (31 haplotypes from 49 individuals), but no phylogeographical structure, was identified in four populations in the putative native range. In contrast, non-native populations showed reduced genetic diversity (7 haplotypes from 249 individuals) and informative phylogeographical structure. Grouping of C. mutica populations into native, east Pacific, and Atlantic groups explained the most among-region variation (59%). This indicates independent introduction pathways for C. mutica to the Pacific and Atlantic coasts of North America. Two dominant haplotypes were identified in eastern and western Atlantic coastal populations, indicating several dispersal routes within the Atlantic. The analysis indicated that several introductions from multiple sources were likely to be responsible for the observed global distribution of C. mutica, but the pathways were least well defined among the Atlantic populations. The four sampled populations of C. mutica in Japan could not be identified as the direct source of the non-native populations examined in this study. The high diversity within the Japan populations indicates that the native range needs to be assessed at a far greater scale, both within and among populations, to accurately assess the source of the global spread of C. mutica. [source] Population structure of Litopenaeus schmitti (Decapoda: Penaeidae) from the Brazilian coast identified using six polymorphic microsatellite lociMOLECULAR ECOLOGY, Issue 12 2003R. Maggioni Abstract The population structure of the only Litopenaeus species occurring in Brazilian waters, the white shrimp L. schmitti, was surveyed by screening six microsatellite loci. High diversity (HE = 0.863; average number of alleles per locus = 37.8) was found across eight geographical locations (2°S to 27°S). Estimates of overall FST(0.0060) were low but significantly different from zero (P < 0.05). FST pairwise estimates and amova revealed a significant discontinuity around a major biogeographical boundary, near Cabo Frio, at 23°S. This separation may have been caused either by historical or on-going hydrogeographical and/or selective factors. [source] Multiple maternal origins of native modern and ancient horse populations in ChinaANIMAL GENETICS, Issue 6 2009C. Z. Lei Summary To obtain more knowledge of the origin and genetic diversity of domestic horses in China, this study provides a comprehensive analysis of mitochondrial DNA (mtDNA) D-loop sequence diversity from nine horse breeds in China in conjunction with ancient DNA data and evidence from archaeological and historical records. A 247-bp mitochondrial D-loop sequence from 182 modern samples revealed a total of 70 haplotypes with a high level of genetic diversity. Seven major mtDNA haplogroups (A,G) and 16 clusters were identified for the 182 Chinese modern horses. In the present study, nine 247-bp mitochondrial D-loop sequences of ancient remains of Bronze Age horse from the Chifeng region of Inner Mongolia in China (c. 4000,2000a bp) were used to explore the origin and diversity of Chinese modern horses and the phylogenetic relationship between ancient and modern horses. The nine ancient horses carried seven haplotypes with rich genetic diversity, which were clustered together with modern individuals among haplogroups A, E and F. Modern domestic horse and ancient horse data support the multiple origins of domestic horses in China. This study supports the argument that multiple successful events of horse domestication, including separate introductions of wild mares into the domestic herds, may have occurred in antiquity, and that China cannot be excluded from these events. Indeed, the association of Far Eastern mtDNA types to haplogroup F was highly significant using Fisher's exact test of independence (P = 0.00002), lending support for Chinese domestication of this haplogroup. High diversity and all seven mtDNA haplogroups (A,G) with 16 clusters also suggest that further work is necessary to shed more light on horse domestication in China. [source] Seedcoat micromorphology of Impatiens (Balsaminaceae) from ChinaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2005YI SONG Seeds of 38 species of Impatiens mostly from south-western China were observed by scanning electron microscopy. High diversity was found in seedcoat micromorphology. Based on the structure and ornamentation of epidermal cells of the seedcoat, particularly the pattern of the arrangement of the cells and the degree of elevation of the anticlinal cell walls, four morphological types can be distinguished, viz, laevigate, granulate, reticulate and protrusive. The laevigate type and granulate type are unique, each occurring in only one species. The other two types are common and can be further divided into subdivisions according to the shape of the epidermal ornamentation of the seedcoat. Descriptions of seed size, shape and seedcoat types are summarized for the genus. Taxonomic and phylogenetic implications of the seedcoat micromorphology are also discussed, in comparison with the available gross morphological and molecular data. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 195,208. [source] Diversity of Escherichia coli O157 in a longitudinal farm study using multiple-locus variable-number tandem-repeat analysisJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2008A.M. Urdahl Abstract Aims:, To perform a longitudinal study of the diversity of Escherichia coli O157 from a ruminant pasture/stream environment using multiple-locus variable-number tandem-repeat analysis (MLVA). Methods and Results:, Samples of faecal droppings from grazing ruminants and from an adjacent stream were tested longitudinally for E. coli O157 by enrichment and immunomagnetic separation (IMS). Using MLVA, 24 different profiles were identified from a total of 231 E. coli O157 isolates, of which 80 were included in a similarity analysis. Four main clusters with several subclusters were observed. Although there was close contact between sheep and cattle during the study period, E. coli O157 was surprisingly not detected from cattle faeces. Conclusions:, The cluster analysis indicated both unrelated and closely related E. coli O157 strains. The choice of loci to target in MLVA is important for the subtyping result, as loci with high diversities are essential for discriminating between closely related isolates. Significance and Impact of the Study:, There is a lack of data available on the use of MLVA to describe E. coli O157 diversity and changes over time in the animal reservoirs and the environment. Such data are needed in order to further develop MLVA as a typing method. [source] Diversity and composition of Arctiidae moth ensembles along a successional gradient in the Ecuadorian AndesDIVERSITY AND DISTRIBUTIONS, Issue 5 2005Nadine Hilt ABSTRACT Andean montane rain forests are among the most species-rich terrestrial habitats. Little is known about their insect communities and how these respond to anthropogenic habitat alteration. We investigated exceptionally speciose ensembles of nocturnal tiger moths (Arctiidae) at 15 anthropogenically disturbed sites, which together depict a gradient of forest recovery and six closed-forest understorey sites in southern Ecuador. At weak light traps we sampled 9211 arctiids, representing 287 species. Arctiid abundance and diversity were highest at advanced succession sites, where secondary scrub or young forest had re-established, followed by early succession sites, and were lowest, but still high, in mature forest understorey. The proportion of rare species showed the reverse pattern. We ordinated moth samples by non-metric multidimensional scaling using the chord-normalized expected species shared index (CNESS) index at various levels of the sample size parameter m. A distinct segregation of arctiid ensembles at succession sites from those in mature forest consistently emerged only at high m -values. Segregation between ensembles of early vs. late succession stages was also clear at high m values only, and was rather weak. Rare species were responsible for much of the faunal difference along the succession gradient, whereas many common arctiid species occurred in all sites. Matrix correlation tests as well as exploration of relationships between ordination axes and environmental variables revealed the degree of habitat openness, and to a lesser extent, elevation, as best predictors of faunal dissimilarity. Faunal differences were not related to geographical distances between sampling sites. Our results suggest that many of the more common tiger moths of Neotropical montane forests have a substantial recolonization potential at the small spatial scale of our study and accordingly occur also in landscape mosaics surrounding nature reserves. These species contribute to the unexpectedly high diversity of arctiid ensembles at disturbed sites, whereas the proportion of rare species declines outside mature forest. [source] Profiling invasive fish species: the importance of phylogeny and human useDIVERSITY AND DISTRIBUTIONS, Issue 4 2005Carles Alcaraz ABSTRACT Understanding the ecological differences between native and invasive species is of considerable scientific and practical interest. We examined such differences between native and invasive inland fish species from the Iberian Peninsula in order to analyse the importance of phylogenetic correction and variability (in addition to central tendency). We collected 26 quantitative and qualitative variables on the ecology, life-history traits and human use of the 69 inland fish species of the Iberian Peninsula, including native, invasive and migratory species. The taxonomic distribution of invasive fish species deviated significantly from world freshwater richness and in contrast to native species, invasive fish belongs to only five taxonomic orders but to a wide spectrum of families not native to the Iberian Peninsula. Because the life-history traits were highly dependent on taxonomy, the results, with or without applying phylogenetic methods, differed and after accounting for phylogeny, invasive species displayed higher and wider latitude in general and a different reproductive season mainly among salmonids and cyprinids. Human use was also significantly different between native and invasive fish species and produced more variability in life-history traits of invasive species and uneven taxonomic distribution because of the high diversity of species introduced. We show that accounting for taxonomy and studying variability in addition to central tendency is important in the comparison of life-history traits between native and invasive species. [source] Integrating highly diverse invertebrates into broad-scale analyses of cross-taxon congruence across the PalaearcticECOGRAPHY, Issue 6 2009Andreas Schuldt Our knowledge on broad-scale patterns of biodiversity, as a basis for biogeographical models and conservation planning, largely rests upon studies on the spatial distribution of vertebrates and plants, neglecting large parts of the world's biodiversity. To reassess the generality of these patterns and better understand spatial diversity distributions of invertebrates, we analyzed patterns of species richness and endemism of a hyperdiverse insect taxon, carabid beetles (ca 11 000 Palaearctic species known), and its cross-taxon congruence with well-studied vertebrates (amphibians, reptiles) and plants across 107,units of the Palaearctic. Based on species accumulation curves, we accounted for completeness of the carabid data by separately examining the western (well-sampled) and eastern (partly less well-sampled) Palaearctic and China (deficient data). For the western Palaearctic, we highlight overall centers of invertebrate, vertebrate and plant diversity. Species richness and endemism of carabids were highly correlated with patterns of especially plant and amphibian diversity across large parts of the Palaearctic. For the well-sampled western Palaearctic, hotspots of diversity integrating invertebrates were located in Italy, Spain and Greece. Only analysis of Chinese provinces yielded low congruence between carabids and plants/vertebrates. However, Chinese carabid diversity is only insufficiently known and China features the highest numbers of annual new descriptions of carabids in the Palaearctic. Even based on the incomplete data, China harbors at least 25% of all Palaearctic carabid species. Our study shows that richness and endemism patterns of highly diverse insects can exhibit high congruence with general large scale patterns of diversity inferred from plants/vertebrates and that hotspots derived from the latter can also include a high diversity of invertebrates. In this regard, China qualifies as an outstanding multi-taxon hotspot of diversity, requiring intense biodiversity research and conservation effort. Our findings extend the limited knowledge on broad-scale invertebrate distributions and allow for a better understanding of diversity patterns across a larger range of the world's biodiversity than usually considered. [source] Botanical richness and endemicity patterns of Borneo derived from species distribution modelsECOGRAPHY, Issue 1 2009Niels Raes This study provides a Borneo-wide, quantitative assessment of botanical richness and endemicity at a high spatial resolution, and based on actual collection data. To overcome the bias in collection effort, and to be able to predict the presence and absence of species, even for areas where no collections have been made, we constructed species distribution models (SDMs) for all species taxonomically revised in Flora Malesiana. Species richness and endemicity maps were based on 1439 significant SDMs. Mapping of the residuals of the richness-endemicity relationship identified areas with higher levels of endemicity than can be expected on the basis of species richness, the endemicity hotspots. We were able to identify one previously unknown region of high diversity, the high mountain peaks of East Kalimantan; and two additional endemicity hotspots, the Müller Mountains and the Sangkulirang peninsula. The areas of high diversity and endemicity were characterized by a relatively small range in annual temperature, but with seasonality in temperatures within that range. Furthermore, these areas were least affected by El Niño Southern Oscillation drought events. The endemicity hotspots were found in areas, which were ecologically distinct in altitude, edaphic conditions, annual precipitation, or a combination of these factors. These results can be used to guide conservation efforts of the highly threatened forests of Borneo. [source] Effect of environmental variables on eukaryotic microbial community structure of land-fast Arctic sea iceENVIRONMENTAL MICROBIOLOGY, Issue 3 2010Brian Eddie Summary Sea ice microbial community structure affects carbon and nutrient cycling in polar seas, but its susceptibility to changing environmental conditions is not well understood. We studied the eukaryotic microbial community in sea ice cores recovered near Point Barrow, AK in May 2006 by documenting the composition of the community in relation to vertical depth within the cores, as well as light availability (mainly as variable snow cover) and nutrient concentrations. We applied a combination of epifluorescence microscopy, denaturing gradient gel electrophoresis and clone libraries of a section of the 18S rRNA gene in order to compare the community structure of the major eukaryotic microbial phylotypes in the ice. We find that the community composition of the sea ice is more affected by the depth horizon in the ice than by light availability, although there are significant differences in the abundance of some groups between light regimes. Epifluorescence microscopy shows a shift from predominantly heterotrophic life styles in the upper ice to autotrophy prevailing in the bottom ice. This is supported by the statistical analysis of the similarity between the samples based on the denaturing gradient gel electrophoresis banding patterns, which shows a clear difference between upper and lower ice sections with respect to phylotypes and their proportional abundance. Clone libraries constructed using diatom-specific primers confirm the high diversity of diatoms in the sea ice, and support the microscopic counts. Evidence of protistan grazing upon diatoms was also found in lower sections of the core, with implications for carbon and nutrient recycling in the ice. [source] Ascomycetes associated with ectomycorrhizas: molecular diversity and ecology with particular reference to the HelotialesENVIRONMENTAL MICROBIOLOGY, Issue 12 2009Leho Tedersoo Summary Mycorrhizosphere microbes enhance functioning of the plant,soil interface, but little is known of their ecology. This study aims to characterize the ascomycete communities associated with ectomycorrhizas in two Tasmanian wet sclerophyll forests. We hypothesize that both the phyto- and mycobiont, mantle type, soil microbiotope and geographical distance affect the diversity and occurrence of the associated ascomycetes. Using the culture-independent rDNA sequence analysis, we demonstrate a high diversity of these fungi on different hosts and habitats. Plant host has the strongest effect on the occurrence of the dominant species and community composition of ectomycorrhiza-associated fungi. Root endophytes, soil saprobes, myco-, phyto- and entomopathogens contribute to the ectomycorrhiza-associated ascomycete community. Taxonomically these Ascomycota mostly belong to the orders Helotiales, Hypocreales, Chaetothyriales and Sordariales. Members of Helotiales from both Tasmania and the Northern Hemisphere are phylogenetically closely related to root endophytes and ericoid mycorrhizal fungi, suggesting their strong ecological and evolutionary links. Ectomycorrhizal mycobionts from Australia and the Northern Hemisphere are taxonomically unrelated to each other and phylogenetically distant to other helotialean root-associated fungi, indicating independent evolution. The ubiquity and diversity of the secondary root-associated fungi should be considered in studies of mycorrhizal communities to avoid overestimating the richness of true symbionts. [source] Phylogenetic 16S rRNA analysis reveals the presence of complex and partly unknown bacterial communities in Tito Bustillo cave, Spain, and on its Palaeolithic paintingsENVIRONMENTAL MICROBIOLOGY, Issue 7 2002Claudia Schabereiter-Gurtner Summary Tito Bustillo cave (Ribadesella, Spain) contains valuable Palaeolithic paintings, which date back 15 000,20 000 years. Since 1969, the cave has been open to the public. Rock wall surfaces, spelaeothems and soils are covered by apparent biofilms of phototrophic microorganisms, which develop under artificial lighting. In addition, rock surfaces present conspicuous bacterial growth in the form of round colonies of different colours and about 1,2 mm in diameter. Even the famous Paintings Panel shows some evident microbial growth. In the present study, bacterial communities on the paintings and on the rock surfaces near the paintings were analysed by culture-independent techniques, including polymerase chain reaction (PCR) amplification of bacterial 16S rRNA genes (16S rDNA), phylogenetic sequence analyses and genetic community fingerprinting by denaturing gradient gel electrophoresis (DGGE). DGGE fingerprints showed complex bacterial community patterns. Forty-one clones matching DGGE bands of the community fingerprints were sequenced, representing about 39% of DNA fragments in the DGGE patterns. Phylogenetic sequence analyses revealed a high number of phylogenetically novel 16S rDNA sequence types and a high diversity of putatively chemotrophic and heterotrophic bacteria. Sequences were phylogenetically most closely related to the Proteobacteria (20 clones), green non-sulphur bacteria (three clones), Planctomycetales order (one clone), Cytophaga,Flexibacter, Bacteroides division (one clone) and the Actinobacteria (four clones). Furthermore, we report the presence of members of the Acidobacterium division (12 clones) in a karstic hypogean environment. Members of this phylum have not so far been detected in these particular environments. [source] Anti-Predator Signals as Advertisements: Evidence in White-Throated Magpie-JaysETHOLOGY, Issue 6 2009Jesse M. S. Ellis Calls and displays elicited by predators usually function as alarms or to inform predators of their detection. However, predator encounters may afford some individuals the opportunity to demonstrate quality or signal their availability. Here, I report on a class of vocal signals produced in predator-elicited displays that share many characteristics with sexually selected song. White-throated magpie-jays (Calocitta formosa) display at low-threat predators while producing ,loud display calls' (LDCs). I use this term because the calls occur primarily in two display contexts (see below) though occasionally in other contexts as well. Such calls and displays are primarily produced by males, and also occur in one other context, at dawn. Playback experiments showed that despite being elicited by predators, males were more likely than females to respond to LDCs, and more likely to respond when their mate was fertile. Over 134 different call types were produced in over 200 displays by 34 males; the largest minimum repertoire size was 67. Presentations of taxidermic raptor mounts elicited some LDCs, but fewer calls and lower diversity than at dawn or in predator approach displays. The male bias and high diversity suggest that LDCs are an outcome of intersexual selection, while their elicitation by predators suggests an alarm function. I propose that male magpie-jays use predator encounters as opportunities to advertise their presence and availability as mates; they use LDCs as songs. Such a communication system seems to have been favored by the unusual social system of magpie-jays, in which female groups defend territories and males have little opportunity to defend resources for mate attraction, forcing them to advertise when females are paying the most attention, during predator encounters. [source] DIVERSIFICATION OF THE AFRICAN GENUS PROTEA (PROTEACEAE) IN THE CAPE BIODIVERSITY HOTSPOT AND BEYOND: EQUAL RATES IN DIFFERENT BIOMESEVOLUTION, Issue 3 2010Luis M. Valente The Cape region of South Africa is a hotspot of flowering plant biodiversity. However, the reasons why levels of diversity and endemism are so high remain obscure. Here, we reconstructed phylogenetic relationships among species in the genus Protea, which has its center of species richness and endemism in the Cape, but also extends through tropical Africa as far as Eritrea and Angola. Contrary to previous views, the Cape is identified as the ancestral area for the radiation of the extant lineages: most species in subtropical and tropical Africa are derived from a single invasion of that region. Moreover, diversification rates have been similar within and outside the Cape region. Migration out of the Cape has opened up vast areas, but those lineages have not diversified as extensively at fine spatial scales as lineages in the Cape. Therefore, higher net rates of diversification do not explain the high diversity and endemism of Protea in the Cape. Instead, understanding why the Cape is so diverse requires an explanation for how Cape species are able to diverge and persist at such small spatial scales. [source] Evidence for plant viruses in the region of Argentina Islands, AntarcticaFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Valery Polischuk Abstract This work focused on the assessment of plant virus occurrence among primitive and higher plants in the Antarctic region. Sampling occurred during two seasons (2004/5 and 2005/6) at the Ukrainian Antarctic Station ,Academician Vernadskiy' positioned on Argentina Islands. Collected plant samples of four moss genera (Polytrichum, Plagiatecium, Sanionia and Barbilophozia) and one higher monocot plant species, Deschampsia antarctica, were further subjected to enzyme-linked immunosorbent assay to test for the presence of common plant viruses. Surprisingly, samples of Barbilophozia and Polytrichum mosses were found to contain antigens of viruses from the genus Tobamovirus, Tobacco mosaic virus and Cucumber green mottle mosaic virus, which normally parasitize angiosperms. By contrast, samples of the monocot Deschampsia antarctica were positive for viruses typically infecting dicots: Cucumber green mottle mosaic virus, Cucumber mosaic virus and Tomato spotted wilt virus. Serological data for Deschampsia antarctica were supported in part by transmission electron microscopy observations and bioassay results. The results demonstrate comparatively high diversity of plant viruses detected in Antarctica; the results also raise questions of virus specificity and host susceptibility, as the detected viruses normally infect dicotyledonous plants. However, the means of plant virus emergence in the region remain elusive and are discussed. [source] Peptidoglycan structure and architectureFEMS MICROBIOLOGY REVIEWS, Issue 2 2008Waldemar Vollmer Abstract The peptidoglycan (murein) sacculus is a unique and essential structural element in the cell wall of most bacteria. Made of glycan strands cross-linked by short peptides, the sacculus forms a closed, bag-shaped structure surrounding the cytoplasmic membrane. There is a high diversity in the composition and sequence of the peptides in the peptidoglycan from different species. Furthermore, in several species examined, the fine structure of the peptidoglycan significantly varies with the growth conditions. Limited number of biophysical data on the thickness, elasticity and porosity of peptidoglycan are available. The different models for the architecture of peptidoglycan are discussed with respect to structural and physical parameters. [source] Transition from arc- to post-collision extensional setting revealed by K,Ar dating and petrology: an example from the granitoids of the Eastern Pontide Igneous Terrane, Arakl,-Trabzon, NE TurkeyGEOLOGICAL JOURNAL, Issue 4 2005Sabah Yilmaz- Abstract The Eastern Pontide Igneous Terrane (EPIT) includes several Cretaceous to Neogene intrusive rocks, ranging in composition from low-K tholeiitic gabbros through calc-alkaline and high-K calc-alkaline metaluminous granitoids or peraluminous leucogranites to alkaline syenites. Such high diversity in age and composition is also accompanied by a broad spectrum in terms of geodynamics,i.e. from arc through syn-collisional thickening to post-collisional extensional regimes. Shallow-seated porphyritic acidic to intermediate rocks are from oldest to youngest, on the basis of field relations, the Gündo,du altered microgranite, the Bo,al, K-feldspar-megacrystic monzogranite and the Uzuntarla porphyritic granodiorite. These rocks, exposed in the southern part of the Arakl, region, east of Trabzon, Turkey, were studied in terms of their mineralogy and petrography, whole-rock geochemistry and hornblende K,Ar dating. The mineralogical and geochemical data reveal an apparent diversity in incompatible-element enrichment and depletion, for the Bo,al, unit and Uzuntarla unit, respectively. The Bo,al, and Uzuntarla units yield hornblende K,Ar ages ranging from 75.7,±,1.55 to 61.4,±,1.47,Ma and from 42.4,±,0.87 to 41.2,±,0.89,Ma, respectively. The diversity in both mineralogy,geochemistry and hornblende K,Ar ages suggests that the Bo,al, and Uzuntarla units are parts of the Cretaceous arc and Eocene post-collision extensional-related igneous activity, respectively, in the EPIT of northern Turkey. Copyright © 2005 John Wiley & Sons, Ltd. [source] How does grazing intensity influence the diversity of plants and insects in a species-rich upland grassland on basalt soils?GRASS & FORAGE SCIENCE, Issue 1 2009B. Dumont Abstract The effect of stocking rate on the species richness, abundance and functional diversity of vascular plants, butterflies and grasshoppers was examined in a semi-natural upland pasture in central France. Over a 5-year period, 3·6-ha plots were continuously grazed by Charolais heifers at 1·4 (High stocking rate), 1·0 (Intermediate) and 0·6 (Low) livestock units (LU) ha,1. To evaluate botanical diversity, percentage cover of all plant species was estimated in late July in ten fixed 1 m × 1 m quadrats per plot. Butterflies were counted on three occasions between late June and early August along three fixed 50-m-long transects per plot using the ,Pollard walk', with grasshoppers being recorded on two occasions along the same transects. Diversity patterns of the three taxa were affected by stocking rate. For plants, species abundance changed more than species number. Abundance of forbs became higher under the Low compared with the High stocking rate. Stress-tolerant grasses were also more abundant in plots grazed at the Low stocking rate, while an opposite trend was observed for competitive grasses. Butterflies consistently responded to alterations in vegetation composition, especially to the dynamics of nectar plants. The species richness of grasshoppers also increased in plots at the Low stocking rate. The Low and Intermediate stocking rates were suitable for providing a high diversity of the three taxonomic groups. The results suggested that at least butterfly diversity would peak in vegetation taller than that of vascular plants. [source] Do life history traits account for diversity of polychaete annelids?INVERTEBRATE BIOLOGY, Issue 4 2002Damhnait McHugh Abstract. Within many phylogenetic assemblages, a pattern of domination has been observed: one or a few clades have had many more speciation events or fewer extinctions than other clades in a particular assemblage. We investigated this phenomenon in the polychaete annelids. Polychaetes comprise ,9000 described species classified in over 70 families and exhibit a great variety of life history strategies. Our goal was to test whether diverse polychaete families are characterized by species with short generation times, high reproductive output, small body size, or with planktotrophic larval development. Each of these factors has been advanced as cause for high diversity in other taxonomic assemblages. Here, we establish that the diversification pattern of polychaete families is non-random, but the data collected show no significant correlations between familial diversity and several life history traits including age at first reproduction, life span, body size, fecundity, and egg size. Pairwise comparisons of sister families do not reveal any trends between familial diversity and any of the life history traits. The great variability of life history traits within polychaete families may explain the lack of significant results; perhaps no trends are seen because polychaete life history traits cannot be generalized at the family level. [source] An Efficient Domino Approach for the Synthesis of Multisubstituted Pyrroles via Gold/Silver-Catalyzed Amination/Cycloisomerization of (Z)-2-En-4-yn-1-olsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Yuhua Lu Abstract An efficient and one-pot synthesis of multisubstituted pyrroles with high diversity and in a regioselective manner from the reactions of suitably substituted (Z)-enynols with amines or sulfonamides under mild reaction conditions has been developed. This synthesis was realized via a cascade process in the presence of gold/silver (Au/Ag) or boron trifluoride,etherate/gold/silver (BF3,Et2O/Au/Ag) catalysts, which could catalyze amination and cycloisomerization reactions in the same vessel. [source] Diversity, endemism and evolution in the Coral TriangleJOURNAL OF BIOGEOGRAPHY, Issue 10 2009J. C. Briggs Abstract In a recent paper by D. R. Bellwood and C. P. Meyer (,Searching for heat in a marine biodiversity hotspot', Journal of Biogeography, 2009, 36, 569,576), the authors had two evident objectives: (1) to disprove the theory that the geographical origins of reef organisms could be determined by locating concentrations of endemic species, and (2) to emphasize that the high diversity of the Coral Triangle was due to an accumulation of species from outside that area. With regard to the first point, no such theory had previously been proposed to my knowledge. Second, the accumulation theory was promoted without consideration of the facts supporting the centre of origin hypothesis, except to dismiss it by saying that it had its origin in pre-continental drift ideas. This short response outlines the properties and evidence for the operation of centres of origin in this region. [source] Older species: a rejuvenation on coral reefs?JOURNAL OF BIOGEOGRAPHY, Issue 4 2004John C. Briggs Abstract Aim To discuss the theory that the present high species diversity and apomorphic character of the coral reef ecosystem is because of the historic accumulation of basal species from marginal habitats. Location The Indo-West Pacific Ocean. Methods The examination of biogeographical patterns from the standpoint of paleontology, phylogeny, genetics, and empirical data. Results Fossil patterns from several clades indicate a gradient of increasing average generic age that extends outward from the high diversity reefs. Successful species that give rise to new species, genera, and families apparently originate from high diversity locations. The tropics have been a major source of evolutionary novelty, not simply a refuge that has accumulated diversity. Many plesiomorphic clades, that once dominated the shallow tropics, are now limited to the deep sea and other safe places. Recent research on several tropical fish families indicates that more apomorphic species inhabit the high diversity reefs. Genetic studies suggest that a decrease in genetic variation extends from the diversity centre toward the outer reaches of the Indo-West Pacific. Empirical data show that it is extremely difficult for species from low diversity areas to invade places of higher diversity. Main conclusions There is no convincing evidence to indicate that basal species from marginal habitats have been able to accumulate on the coral reefs. Once such species have been displaced from a high diversity environment, there is apparently no return. The evolutionary innovations that contribute to the origination of new phyletic lines take place under conditions of high diversity and maximum competition. [source] Spatial patterns of disparity and diversity of the Recent cuttlefishes (Cephalopoda) across the Old WorldJOURNAL OF BIOGEOGRAPHY, Issue 8 2003Pascal Neige Abstract Aim Diversity and disparity metrics of all Recent cuttlefishes are studied at the macroevolutionary scale (1) to establish the geographical biodiversity patterns of these cephalopods at the species level and (2) to explore the relationships between these two metrics. Location Sampling uses what is known about these tropical, subtropical and warm temperate cephalopods of the Old World based on a literature review and on measurements of museum specimens. Some 111 species spread across seventeen biogeographical areas serve as basic units for exploring diversity and disparity metrics in space. Methods Landmarks describe the shape of the cuttlebone (the inner shell of the sepiids) and differences between shapes are quantified using relative warp analyses. Relative warps are thus used as the morphological axis for constructing morphospaces whose characteristics are described by disparity indices: total variance, range, and minimum and maximum of relative warps. These are analysed and then compared with the diversity (species richness) metric. Results Results show no significant latitudinal or longitudinal gradients either for diversity or for disparity. Around the coast of southern Africa, disparity is high regardless of whether diversity (species richness) is high or low. In the ,East Indies' area disparity is low despite the high diversity. Main conclusions The relationship between diversity and disparity is clearly not linear and no simple adjustment models seem to fit. The number of species in a given area does not predict its disparity level. The particular pattern of southern Africa may be the result of paleogeographical changes since the Eocene, whereas that of the ,East Indies' may indicate that this area could act as a centre of origin. However, the lack of any clear phylogenetical hypothesis precludes the study from providing any explanation of the observed patterns. [source] Diversity, dynamics and reproduction in a community of small mammals in Upper Guinea, with emphasis on pygmy mice ecologyAFRICAN JOURNAL OF ECOLOGY, Issue 3 2010Elisabeth Fichet-Calvet Abstract As part of a large survey on reservoirs of Lassa fever in Guinea, three villages were investigated in high endemic zone, close to Sierra Leone border. Biodiversity of the small mammal community is presented in this study through a standardized trapping in houses, cultivations and forest. Identification of the small mammals was based on morphology and by molecular technique for sibling species. Of the 1123 specimens collected in 2003,2005, we identified seventeen species (thirteen Muridae, four Soricidae), leading to high diversity (Shannon index = 1.6,1.8) and high equitability (evenness index = 0.7,0.8) in cultivations and forest. In houses conversely, the rodent community was dominated by Mastomys natalensis (95,98%), leading to low diversity and equitability. Dynamics and reproduction were investigated in two species of pygmy mice, Mus mattheyi and Mus minutoides, two species of Praomys, P. daltoni and P. rostratus, and in Mastomys erythroleucus. The pygmy mice were abundant in cultivations in early rainy season, and reproduced from rainy to dry season. Praomys daltoni was also found more abundant in cultivations and seemed to reproduce between rainy and dry season, whereas P. rostratus preferred forest and cultivations in late rainy season, and reproduced throughout the year. Finally, M. erythroleucus was more abundant in forest in dry season, and seemed to reproduce from late rainy to dry season. This species had a low occurrence (6.5%) in the Faranah's zone, and probably lived at its southern limit in Guinea. The presence of other Murinae, such as M. natalensis, Praomys spp as possible competitors in the same habitats, is discussed. For the first time, this study relates population biology of pygmy mice with molecular identification. Résumé Dans le cadre d'une vaste étude des réservoirs de la fièvre de Lassa en Guinée, trois villages ont étéétudiés dans une zone de forte endémie près de la frontière de la Sierra Leone. La biodiversité de la communauté de petits mammifères est présentée dans cette étude grâce à un piégeage standardisé dans les maisons, les cultures et les forêts. L'identification des petits mammifères est réalisée sur la base de leur morphologie et de techniques moléculaires dans le cas d'espèces jumelles. Parmi les 1123 spécimens récoltés de 2003 à 2005, nous avons identifié dix-sept espèces (treize Muridae, quatre Soricidae), indiquant une grande diversité (Indice de Shannon = 1,6 à 1,8) et une grande équitabilité (indice d'équitabilité = 0,7 à 0,8) dans les cultures et les forêts. Dans les maisons en revanche, la communauté de rongeurs était dominée par Mastomys natalensis (95 à 98%), conduisant à une faible diversité et équitabilité. La dynamique et la reproduction de deux espèces de souris naines, Mus mattheyi et M. minutoides, deux espèces de Praomys, P. daltoni et P. rostratus, et de Mastomys erythroleucus ont étéétudiées également. Les souris naines étaient abondantes dans les cultures au début de la saison des pluies, se reproduisant de la saison des pluies à la saison sèche. Praomys daltoni fut aussi trouvé en plus grand nombre dans les cultures et semblait se reproduire entre la saison des pluies et la saison sèche alors que P. rostratus préférait les forêts et les cultures à la fin de la saison des pluies et se reproduisait toute l'année. Enfin, M. erythroleucusétait plus abondant en forêt en saison sèche et semblait se reproduire de la fin de la saison des pluies à la saison sèche. Cette espèce était peu présente (6,5%) dans la zone de Faranah et était probablement en Guinée à la limite sud de son aire de répartition. La présence d'autres Murinae, comme M. natalensis et Praomys spp. est discutée en tant que compétiteurs possibles dans les même habitats. Pour la première fois, cette étude relate la biologie des populations de souris naines grâce à une identification moléculaire. [source] Spiders as potential indicators of elephant-induced habitat changes in endemic sand forest, Maputaland, South AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Charles R. Haddad Abstract Elephant impacts on spider assemblages, and the potential use of spiders as indicators of habitat changes was assessed in central Maputaland, South Africa. Three habitats, namely undisturbed sand forest, elephant disturbed sand forest and mixed woodland, were sampled. To ensure a thorough representation of all spider guilds, spiders were collected by tree beating, sweep netting, active searching, leaf litter sifting and pitfall traps. In total, 2808 individual spiders, representing 36 families, 144 determined genera and 251 species were collected. Spider abundance was highest in the undisturbed sand forest (n = 1129, S = 179), followed by elephant disturbed sand forest (n = 1006, S = 165) and mixed woodland (n = 673, S = 171). Assemblages of the two sand forests were more similar than to the mixed woodland assemblage. Active hunting species were indicators of the more open vegetation of elephant disturbed sand forest (six active hunters, no web-builders) and mixed woodland (ten active hunters, one web-builder), whereas web-builders are indicators of the dense, complex vegetation structure of undisturbed sand forest (six web-builders, three active hunters). Elephant-induced changes to the vegetation structure in this high diversity, high endemism region result in changes in the composition of spider assemblages, and may need to be mitigated by management intervention. Résumé L'impact des éléphants sur les assemblages d'araignées, et l'utilisation éventuelle des araignées comme indicateurs de changements des habitats, ont étéévalués dans le centre du Maputaland, en Afrique du Sud. Trois habitats ont étééchantillonnés, à savoir la forêt sableuse intacte, la forêt sableuse perturbée par des éléphants et la forêt mixte. Pour garantir une représentation complète de toutes les guildes d'araignées, on a récolté des araignées en frappant sur les arbres, en agitant des filets, en pratiquant une recherche active, en tamisant la litière de feuilles, et avec des pièges. Au total, on a récolté 2 808 araignées; représentant 36 familles, 144 genres déterminés et 251 espèces. L'abondance d'araignées était la plus grande dans la forêt sableuse non perturbée (n = 1129, S = 179), suivie par la forêt sableuse perturbée par les éléphants (n = 1006, S = 165), puis par la forêt mixte (n = 673, S = 171). Les assemblages des deux forêts sableuses étaient plus semblables entre eux qu'avec celui de la forêt mixte. Les espèces d'araignées qui chassent activement étaient des indicateurs de la végétation plus ouverte de la forêt perturbée par les éléphants (six chasseurs actifs, aucun constructeur de toile) et de la forêt mixte (dix chasseurs actifs, un constructeur de toile), alors que les constructeurs de toile étaient des indicateurs de la structure dense et complexe de la végétation de la forêt sableuse intacte (six constructeurs de toile, trois chasseurs actifs). Les éléphants induisaient des changements dans la structure de la végétation de cette région à la diversitéélevée et d'un fort endémisme, ce qui entraînait des modifications de la composition des assemblages d'araignées. Cela pourrait devoir être atténué par une intervention de la gestion. [source] Pollution status of a tropical forest river using aquatic insects as indicatorsAFRICAN JOURNAL OF ECOLOGY, Issue 1 2010Tunde Ohiokhioya Thadeus Imoobe Abstract Aquatic insects inhabiting Okhuo River, in a tropical forest near Benin City, Southern Nigerian, were studied between January and December 2006 to determine the taxa composition, diversity, EPT index, relative proportions of the various groups and hence the pollution level of the waterbody. Three stations were selected and sampled monthly using the kick sampling technique. A total of 3235 individual aquatic insects belonging to 24 taxa distributed among 23 genera in six orders were collected. The insect orders occurred in the following order of dominance: Ephemeroptera > Odonata > Coleoptera > Diptera > Plecoptera > Tricoptera. Based on the diverse composition of the community dominated by organisms intolerant of organic enrichment, and the high diversity and EPT index, water quality in Okhuo River is not significantly degraded. Community composition varies seasonally, with a trend toward a declining proportion during the rainy season and increasing proportions during the dry season. Aquatic insect composition in Okhuo River compares favourably with those in similar, relatively undisturbed forest streams and rivers in Nigeria, but the diversity and proportional distribution of taxa vary considerably between streams. Résumé Les insectes aquatiques qui vivent dans la rivière Okhuo près de la ville de Benin, au sud du Nigeria, ont étéétudiés entre janvier et décembre 2006 afin de déterminer la composition des taxons, leur diversité, l'indice EPT, les proportions relatives des différents groupes et, de là, le taux de pollution de la rivière. On a sélectionné trois stations qui ont étééchantillonnées chaque mois en utilisant la technique d'échantillonnage par coups de pied. On a collecté un total de 3 235 insectes aquatiques appartenant à 24 taxons répartis entre 23 genres de six ordres. Les ordres des insectes se plaçaient dans l'ordre de dominance suivant : Ephéméroptères > Odonates > Coléoptères > Diptères > Plécoptères > Trichoptères. Si l'on se base sur la composition diversifiée de la communauté où dominent des organismes intolérants aux enrichissements organiques, et sur la grande diversité et l'indice EPT, on peut dire que la qualité de l'eau de la rivière Okhuo n'est pas significativement dégradée. La composition de la communauté varie avec les saisons, avec une tendance à la diminution au cours de la saison des pluies et à une augmentation au cours de la saison sèche. La composition des insectes aquatiques de la rivière Okhuo se compare avantageusement avec celles des cours d'eau semblables des forêts intactes du Nigeria, mais la diversité et la distribution proportionnelle des différents taxons varient considérablement entre les cours d'eau. [source] | |||||||||||||||||||||||||||||||||||||