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Sample records for species distribution antimicrobial

  1. Distribution and Antimicrobial Resistance Profile of Yersinia Species Isolated From Chicken and Beef Meat

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    Shadi Aghamohammad

    2015-11-01

    Full Text Available Background: Foodborne diseases are widespread and growing public health problem in developed and developing countries. There are many microorganisms act as etiological agents for foodborne diseases such as Campylobacter spp., Listeria, Staphylococcos, Salmonella, Bacillus, Yersinia spp. High prevalence of gastrointestinal illness, including fatal cases attributable to yersiniosis, is also observed in many developing countries. Objectives: The purpose of this study was to investigate the prevalence of Yersinia enterocolitica and other Yersinia species in meat and chicken samples in various seasons and to determine their antibiotic resistance profile. Materials and Methods: To investigate the prevalence of Yersinia spp., a total of 450 samples, including chicken (n = 226 and beef meat (n = 224 were collected from supermarkets in Tehran. All samples were transported on ice to the laboratory and microbiological analysis was carried out within 2 hours after the collection. Susceptibility testing of bacterial strains was according to CLSI guideline at 28˚C by the disk diffusion assay. Results: From a total of 450 samples, (226 chickens and 224 beef meats, 70 (15.5% samples were positive for Yersinia spp. Of these isolates, (80% 56 species were identified as Y. enterocolitica, 8 (11% as Y. frederiksenii, 5 (7% as Y. intermedia and 1 (1.4% as Y. kristensenii. The highest rate of resistance was seen against cephalotin (98%, and ampicillin (52%. However, gentamicin and chloramphenicol were the most active antibiotics against the target cultures. Considering the season of isolation, Yersinia spp. were frequently isolated in autumn (52%, followed by spring (29%. Conclusions: Y. enterocolitica was the most spp. distributed among other species. Many factors, such as isolation assay, season, and geographical location play critical role in reports of increase or decrease in the prevalence of the Yersinia spp. all over the world. Our findings demonstrate that

  2. antimicrobial susceptibility pattern of Salmonella species

    African Journals Online (AJOL)

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    ABSTRACT. Treatment of enteric fever is increasingly becoming very challenging due to the increasing wave of antibiotic resistance. This study is a review of the contemporary antimicrobial susceptibility pattern of. Salmonella species. The antimicrobial susceptibility pattern of Salmonella species to a wide range of.

  3. Species distribution and resistance patterns to growth-promoting antimicrobials of enterococci isolated from pigs and chickens in Korea.

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    Hwang, In Yeong; Ku, Hyun Ok; Lim, Suk Kyung; Park, Choi Kyu; Jung, Gab Su; Jung, Suk Chan; Nam, Hyang Mi

    2009-11-01

    A total of 147 Enterococcus faecium and 165 Enterococcus faecalis isolates from fecal samples of chickens and pigs at slaughterhouses in Korea were tested for their resistance to 8 growth-promoting antimicrobials commonly used in animals and quinupristin and dalfopristin. Resistance to most antimicrobials was very common among both E. faecalis and E. faecium. In particular, E. faecalis showed almost no susceptibility to all the antimicrobials tested except penicillin and flavomycin, to which 1.4% and less than 24% showed resistance, respectively. Although the prevalence of resistance was lower than in E. faecalis, E. faecium showed relatively uniform resistance to all the agents tested. Among the antimicrobials tested, virginiamycin and penicillin were the most effective against E. faecium isolates: less than 31% and 41% showed resistance to those 2 antimicrobials, respectively. Penicillin was the only agent that showed relatively strong activity against both E. faecalis and E. faecium. Resistance observed in E. faecalis and E. faecium against most antimicrobials used for growth promotion was more prevalent in Korea than in European countries. The current study is the first report of resistance against feed additive antimicrobials in enterococcal isolates from livestock in Korea.

  4. antimicrobial susceptibility pattern of Salmonella species

    African Journals Online (AJOL)

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    GLOBAL JOURNAL OF COMMUNITY MEDICINE VOL. 2 NO. 1 & 2 2009: 5 - ... This study is a review of the contemporary antimicrobial susceptibility pattern of. Salmonella species. ... south-east Asia, parts of Latin America, the. Caribbean, and ...

  5. Species distribution, virulence factors, and antimicrobial resistance of Acinetobacter spp. isolates from dogs and cats: a preliminary study.

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    Kimura, Yui; Harada, Kazuki; Shimizu, Takae; Sato, Tomomi; Kajino, Akari; Usui, Masaru; Tamura, Yutaka; Tsuyuki, Yuzo; Miyamoto, Tadashi; Ohki, Asami; Watarai, Masahisa

    2018-05-12

    We investigated the prevalence of virulence factors and antimicrobial resistance among 67 Acinetobacter spp. isolates, consisting of 21 Acinetobacter baumannii and 46 non-baumannii Acinetobacter from companion animals. The PCR analysis showed that the most prevalent virulence gene was afa/draBC (29.9%), followed by papC (22.4%) and cvaC (20.9%). Antimicrobial susceptibility testing revealed that resistance to gentamicin (14.9%) and ciprofloxacin (11.9%) was relatively prevalent. Five gentamicin- and/or ciprofloxacin-resistant A. baumannii strains were assigned to ST25, ST149, ST164, ST203, and ST1198. All ciprofloxacin-resistant isolates harbored point mutations in gyrA and/or parC. This is the first preliminary monitoring of animal-origin Acinetobacter spp. in Japan. © 2018 The Societies and John Wiley & Sons Australia, Ltd.

  6. Hierarchical species distribution models

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    Hefley, Trevor J.; Hooten, Mevin B.

    2016-01-01

    Determining the distribution pattern of a species is important to increase scientific knowledge, inform management decisions, and conserve biodiversity. To infer spatial and temporal patterns, species distribution models have been developed for use with many sampling designs and types of data. Recently, it has been shown that count, presence-absence, and presence-only data can be conceptualized as arising from a point process distribution. Therefore, it is important to understand properties of the point process distribution. We examine how the hierarchical species distribution modeling framework has been used to incorporate a wide array of regression and theory-based components while accounting for the data collection process and making use of auxiliary information. The hierarchical modeling framework allows us to demonstrate how several commonly used species distribution models can be derived from the point process distribution, highlight areas of potential overlap between different models, and suggest areas where further research is needed.

  7. Bounding species distribution models

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    Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

    2011-10-01

    Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

  8. Bounding Species Distribution Models

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    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  9. Occurrence, species distribution, antimicrobial resistance and clonality of methicillin- and erythromycin-resistant staphylococci in the nasal cavity of domestic animals

    DEFF Research Database (Denmark)

    Bagcigil, Funda A.; Moodley, Arshnee; Baptiste, Keith E.

    2007-01-01

    beta-Lactams and macrolides are important antibiotics for treatment of staphylococcal infections in both humans and animals. The aim of the study was to investigate the occurrence, species distribution and clonality of methicillin and erythromycin-resistant staphylococci in the nasal cavity of dogs......, horses, pigs, and cattle in Denmark. Nasal swabs were collected from a total of 400 animals, including 100 individuals of each species. Methicillin and erythromycin-resistant staphylococci were isolated on selective media, identified by 16S rDNA sequencing, and typed by pulsed field gel electrophoresis...... (PFGE). Methicillin-resistant coagulase-negative staphylococci (MRCoNS) harbouring mecA were isolated from horses (50%) and dogs (13%), but not from food animals. The species identified were S. haemolyticus (n = 21), S. vitulinus (n = 19), S. sciuri (n = 13), S. epidermidis (n = 8), and S. warneri (n...

  10. Antimicrobial properties of poriferan species from Indian waters

    Digital Repository Service at National Institute of Oceanography (India)

    Mokashe, S.S.; Tulaskar, A.S.; Venkat, K.; Wagh, A.B.

    Poriferan species belonging to Class Demospongiae were collected from the rocky intertidal pools of Ratnagiri (Maharashtra, India) and extracted with methanol. The methanol extracts were tested for antimicrobial activity against six fouling...

  11. Approaches for quantifying antimicrobial consumption per animal species based on national sales data: a Swiss example, 2006 to 2013.

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    Carmo, Luís P; Schüpbach-Regula, Gertraud; Müntener, Cedric; Chevance, Anne; Moulin, Gérard; Magouras, Ioannis

    2017-02-09

    Antimicrobial use in animals is known to contribute to the global burden of antimicrobial resistance. Therefore, it is critical to monitor antimicrobial sales for livestock and pets. Despite the availability of veterinary antimicrobial sales data in most European countries, surveillance currently lacks consumption monitoring at the animal species level. In this study, alternative methods were investigated for stratifying antimicrobial sales per species using Swiss data (2006-2013). Three approaches were considered: (i) Equal Distribution (ED) allocated antimicrobial sales evenly across all species each product was licensed for; (ii) Biomass Distribution (BMD) stratified antimicrobial consumption, weighting the representativeness of each species' total biomass; and (iii) Longitudinal Study Extrapolation (LSE) assigned antimicrobial sales per species based on a field study describing prescription patterns in Switzerland. LSE is expected to provide the best estimates because it relies on field data. Given the Swiss example, BMD appears to be a reliable method when prescription data are not available, whereas ED seems to underestimate consumption in species with larger populations and higher treatment intensity. These methods represent a valuable tool for improving the monitoring systems of veterinary antimicrobial consumption across Europe. This article is copyright of The Authors, 2017.

  12. Antimicrobials of Bacillus species: mining and engineering

    NARCIS (Netherlands)

    Zhao, Xin

    2016-01-01

    Bacillus sp. have been successfully used to suppress various bacterial and fungal pathogens. Due to the wide availability of whole genome sequence data and the development of genome mining tools, novel antimicrobials are being discovered and updated,;not only bacteriocins, but also NRPs and PKs. A

  13. Antimicrobial effect of probiotics on bacterial species from dental plaque.

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    Zambori, Csilla; Morvay, Attila Alexandru; Sala, Claudia; Licker, Monica; Gurban, Camelia; Tanasie, Gabriela; Tirziu, Emil

    2016-03-31

    The antimicrobial role of probiotic Lactobacillus casei subspecies casei DG (L. casei DG) and of the mix culture of probiotic Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 was tested on species of Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera from supragingival sites from dogs with dental disease of different breed, age, sex, weight, and diet. The research was conducted on these four genera because of their importance in zoonotic infections after dog bites. Species from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera were isolated and identified. To test the antimicrobial efficacy of L. casei DG and the mixed culture of probiotic L. acidophilus LA-5 and Bifidobacterium bifidum BB-12 on the pathogenic species, the agar overlay method was used. L. casei DG had a bactericidal effect on all analyzed species isolated from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera after 24 hours of incubation. The mixed probiotic culture made up of L. acidophilus LA-5 and Bifidobacterium BB-12 species had no bactericidal effect on the species of Staphylococcus and Streptococcus genera, which were resistant. However, it had a bacteriostatic effect on several species of Pasteurella and Neisseria genera. This work highlights the antimicrobial potential of probiotics in vitro, demonstrating that the probiotic L. casei DG has a bactericidal effect on all analyzed species isolated from dental plaque and that the mix culture of probiotic L. acidophilus LA-5 and Bifidobacterium BB-12 has only a bacteriostatic effect.

  14. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

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    Snežana Marković

    2011-08-01

    Full Text Available The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+ bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells.

  15. Antimicrobial Screening of Some Exotic Tree Species of Rajasthan Desert

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    B.B.S. Kapoor* and Shelja Pandita

    2013-01-01

    Antimicrobial screening of ethyl ether and alcoholic extracts of leaves of four selected exotic tree species growing inRajasthan Desert was carried out. Colophospermum mopane, Holoptelea integrifolia, Kigelia pinnata andPutranjiva roxburghii showed positive reactions against bacterial pathogens i.e. Staphylococcus aureus, Escherichiacoli and a fungal pathogen Candida albicans.

  16. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

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    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Čomić, Ljiljana; Đačić, Dragana; Ćurčić, Milena; Marković, Snežana

    2011-01-01

    The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells. PMID:21954369

  17. Antimicrobial susceptibility profile of Listeria species isolated from ...

    African Journals Online (AJOL)

    The antimicrobial susceptibility profile of L. monocytogenes and other Listeria species isolated from some ready-to-eat (RTE) foods sold in Kano metropolis, north-western Nigeria was carried out using disc-diffusion method. The results obtained showed that L. monocytogenes was moderately susceptible to all the ...

  18. Species Distribution and Antibiotic Resistance in Coagulase ...

    African Journals Online (AJOL)

    Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife, Nigeria, was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional ...

  19. Frequency and antimicrobial susceptibility of acinetobacter species isolated from blood samples of paediatric patients

    International Nuclear Information System (INIS)

    Javed, A.; Zafar, A.; Ejaz, H.; Zubair, M.

    2012-01-01

    Objective: Acinetobacter species is a major nosocomial pathogen causing serious infections in immuno-compromised and hospitalized patients. The aim of this study was to determine the frequency and antimicrobial susceptibility pattern of Acinetobacter species in blood samples of paediatric patients. Methodology: This cross sectional observational study was conducted during January to October, 2011 at The Children's Hospital and Institute of Child Health, Lahore. A total number of 12,032 blood samples were analysed during the study period. Acinetobacter species were Bauer disc diffusion method. Results: The blood cultures showed growth in 1,141 cultures out of which 46 (4.0%) were Acinetobacter species. The gender distribution of Acinetobacter species was 29 (63.0%) in males and 17 (37.0%) in females. A good antimicrobial susceptibility pattern of Acinetobacter species was seen with sulbactam-cefoperazone (93.0%), imepenem and meropenem (82.6% (30.4%) was poor. Conclusion: The results of the present study shows high rate of resistance of Acinetobacter species with cephalosporins in nosocomial infections. The sulbactam-cefoperazone, carbapenems and piperacillin-tazobactam showed effective antimicrobial susceptibility against Acinetobacter species. (author)

  20. Antimicrobial Activity and Chemical Composition of Essential Oils from Verbenaceae Species Growing in South America

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    Cristina M. Pérez Zamora

    2018-03-01

    Full Text Available The Verbenaceae family includes 2600 species grouped into 100 genera with a pantropical distribution. Many of them are important elements of the floras of warm-temperature and tropical regions of America. This family is known in folk medicine, and its species are used as digestive, carminative, antipyretic, antitussive, antiseptic, and healing agents. This review aims to collect information about the essential oils from the most reported species of the Verbenaceae family growing in South America, focusing on their chemical composition, antimicrobial activity, and synergism with commercial antimicrobials. The information gathered comprises the last twenty years of research within the South American region and is summarized taking into consideration the most representative species in terms of their essential oils. These species belong to Aloysia, Lantana, Lippia, Phyla, and Stachytarpheta genera, and the main essential oils they contain are monoterpenes and sesquiterpenes, such as β-caryophyllene, thymol, citral, 1,8-cineole, carvone, and limonene. These compounds have been found to possess antimicrobial activities. The synergism of these essential oils with antibiotics is being studied by several research groups. It constitutes a resource of interest for the potential use of combinations of essential oils and antibiotics in infection treatments.

  1. Antimicrobial activity of some Ganoderma species from Nigeria.

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    Ofodile, L N; Uma, N U; Kokubun, T; Grayer, R J; Ogundipe, O T; Simmonds, M S J

    2005-04-01

    The crude n-hexane:diethyl ether, chloroform:acetone and methanol extracts of four species of Ganoderma (Ganoderma colossum (Fr.) C. F. Baker, G. resinaceum Boud., G. lucidum (cf.) (Curtis) P. Karst. and G. boninense (cf.) Pat.), from Nigeria, were tested for antimicrobial activity. The three solvent extracts of all the species of Ganoderma were active against Pseudomonas syringae and Bacillus subtilis, whereas none of the extracts were active against Cladosporium herbarum. Preliminary thin layer chromatography chemical tests on these extracts of Ganoderma showed that they contained compounds that stained blue-violet and blue or green when sprayed with anisaldehyde-sulphuric acid or Dragendorff, respectively. The profile of compounds in the extracts showed some variation among the four species. (c) 2005 John Wiley & Sons, Ltd.

  2. Differential activity of innate defense antimicrobial peptides against Nocardia species.

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    Rieg, Siegbert; Meier, Benjamin; Fähnrich, Eva; Huth, Anja; Wagner, Dirk; Kern, Winfried V; Kalbacher, Hubert

    2010-02-23

    Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human alpha-defensins human neutrophil peptides (HNPs) 1-3, human beta-defensin (hBD)-3 and cathelicidin LL-37 as well as bovine beta-defensins lingual and tracheal antimicrobial peptides (LAP, TAP) and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. Whereas N. farcinica ATCC 3318 and N. nova ATCC 33726 were found to be susceptible to all investigated human and bovine AMPs, N. asteroides ATCC 19247 was killed exclusively by neutrophil-derived human alpha-defensins HNP 1-3 and bovine indolicidin. N. brasiliensis ATCC 19296 was found to exhibit complete resistance to investigated human AMPs and to be susceptible only to bovine indolicidin. Selected AMPs are capable to contribute to the first line of defense against Nocardia, yet, susceptibility appears to vary across different Nocardia species. Obtained results of neutrophil-derived AMPs to possess the broadest antinocardial spectrum are remarkable, since nocardiosis is characterized by a neutrophil-rich infiltrate in vivo.

  3. Differential activity of innate defense antimicrobial peptides against Nocardia species

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    Wagner Dirk

    2010-02-01

    Full Text Available Abstract Background Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs 1-3, human β-defensin (hBD-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. Results Whereas N. farcinica ATCC 3318 and N. nova ATCC 33726 were found to be susceptible to all investigated human and bovine AMPs, N. asteroides ATCC 19247 was killed exclusively by neutrophil-derived human α-defensins HNP 1-3 and bovine indolicidin. N. brasiliensis ATCC 19296 was found to exhibit complete resistance to investigated human AMPs and to be susceptible only to bovine indolicidin. Conclusion Selected AMPs are capable to contribute to the first line of defense against Nocardia, yet, susceptibility appears to vary across different Nocardia species. Obtained results of neutrophil-derived AMPs to possess the broadest antinocardial spectrum are remarkable, since nocardiosis is characterized by a neutrophil-rich infiltrate in vivo.

  4. Epidemiology and susceptibility to antimicrobial agents of the main Nocardia species in Spain.

    Science.gov (United States)

    Valdezate, Sylvia; Garrido, Noelia; Carrasco, Gema; Medina-Pascual, María J; Villalón, Pilar; Navarro, Ana M; Saéz-Nieto, Juan A

    2017-03-01

    The aims of this study were to explore the clinical distribution, by species, of the genus Nocardia and to assess the antimicrobial susceptibilities of the 10 most prevalent species identified in Spain. Over a 10 year period (2005-14), 1119 Nocardia strains were molecularly identified and subjected to the Etest. The distribution and resistance trends over the sub-periods 2005-09 and 2010-14 were also examined. Of the strains examined, 82.9% belonged to the following species: Nocardia cyriacigeorgica (25.3%), Nocardia nova (15.0%), Nocardia abscessus (12.7%), Nocardia farcinica (11.4%), Nocardia carnea (4.3%), Nocardia brasiliensis (3.5%), Nocardia otitidiscaviarum (3.1%), Nocardia flavorosea (2.6%), Nocardia rhamnosiphila (2.6%) and Nocardia transvalensis (2.4%). Their prevalence values were similar during 2005-09 and 2010-14, except for those of N. abscessus , N. farcinica and N. transvalensis , which fell significantly in the second sub-period ( P ≤  0.05). The major location of isolation was the respiratory tract (∼86%). Half (13/27) of all strains from the CNS were N. farcinica . Significant differences in MIC results were recorded for some species between the two sub-periods. According to the CLSI's breakpoints, low resistance rates (≤15%) were recorded for seven species with respect to cefotaxime, imipenem and tobramycin; five species showed similar rates with respect to trimethoprim/sulfamethoxazole. Linezolid and amikacin were the most frequently active agents. The accurate identification of the infecting species and the determination of its susceptibility to antimicrobial agents, given the large number of strains with atypical patterns, are crucial if patients with nocardiosis are to be successfully treated. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Antimicrobial susceptibility and distribution of inhibition zone diameters of bovine mastitis pathogens in Flanders, Belgium.

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    Supré, K; Lommelen, K; De Meulemeester, L

    2014-07-16

    In dairy farms, antimicrobial drugs are frequently used for treatment of (sub)clinical mastitis. Determining the antimicrobial susceptibility of mastitis pathogens is needed to come to a correct use of antimicrobials. Strains of Staphylococcus aureus (n=768), Streptococcus uberis (n=939), Streptococcus dysgalactiae (n=444), Escherichia coli (n=563), and Klebsiella species (n=59) originating from routine milk samples from (sub)clinical mastitis were subjected to the disk diffusion method. Disks contained representatives of frequently used antibiotics in dairy. A limited number of clinical breakpoints were available through CLSI, and showed that susceptibility of Staph. aureus, E. coli, and Klebsiella was moderate to high. For streptococcal species however, a large variation between the tested species and the different antimicrobials was observed. In a next step, wild type populations were described based on epidemiological cut off values (EUCAST). Because of the limited number of official cut off values, the data were observed as a mastitis subpopulation and self-generated cut off values were created and a putative wild type population was suggested. The need for accurate clinical breakpoints for veterinary pathogens is high. Despite the lack of these breakpoints, however, a population study can be performed based on the distribution of inhibition zone diameters on the condition that a large number of strains is tested. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Suppression of antimicrobial peptide expression by ureaplasma species.

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    Xiao, Li; Crabb, Donna M; Dai, Yuling; Chen, Yuying; Waites, Ken B; Atkinson, T Prescott

    2014-04-01

    Ureaplasma species commonly colonize the adult urogenital tract and are implicated in invasive diseases of adults and neonates. Factors that permit the organisms to cause chronic colonization or infection are poorly understood. We sought to investigate whether host innate immune responses, specifically, antimicrobial peptides (AMPs), are involved in determining the outcome of Ureaplasma infections. THP-1 cells, a human monocytoid tumor line, were cocultured with Ureaplasma parvum and U. urealyticum. Gene expression levels of a variety of host defense genes were quantified by real-time PCR. In vitro antimicrobial activities of synthetic AMPs against Ureaplasma spp. were determined using a flow cytometry-based assay. Chromosomal histone modifications in host defense gene promoters were tested by chromatin immunoprecipitation (ChIP). DNA methylation status in the AMP promoter regions was also investigated. After stimulation with U. parvum and U. urealyticum, the expression of cell defense genes, including the AMP genes (DEFB1, DEFA5, DEFA6, and CAMP), was significantly downregulated compared to that of TNFA and IL-8, which were upregulated. In vitro flow cytometry-based antimicrobial assay revealed that synthetic peptides LL-37, hBD-3, and hBD-1 had activity against Ureaplasma spp. Downregulation of the AMP genes was associated with chromatin modification alterations, including the significantly decreased histone H3K9 acetylation with U. parvum infection. No DNA methylation status changes were detected upon Ureaplasma infection. In conclusion, AMPs have in vitro activity against Ureaplasma spp., and suppression of AMP expression might be important for the organisms to avoid this aspect of the host innate immune response and to establish chronic infection and colonization.

  7. Horizontal antimicrobial resistance transfer drives epidemics of multiple Shigella species.

    Science.gov (United States)

    Baker, Kate S; Dallman, Timothy J; Field, Nigel; Childs, Tristan; Mitchell, Holly; Day, Martin; Weill, François-Xavier; Lefèvre, Sophie; Tourdjman, Mathieu; Hughes, Gwenda; Jenkins, Claire; Thomson, Nicholas

    2018-04-13

    Horizontal gene transfer has played a role in developing the global public health crisis of antimicrobial resistance (AMR). However, the dynamics of AMR transfer through bacterial populations and its direct impact on human disease is poorly elucidated. Here, we study parallel epidemic emergences of multiple Shigella species, a priority AMR organism, in men who have sex with men to gain insight into AMR emergence and spread. Using genomic epidemiology, we show that repeated horizontal transfer of a single AMR plasmid among Shigella enhanced existing and facilitated new epidemics. These epidemic patterns contrasted with slighter, slower increases in disease caused by organisms with vertically inherited (chromosomally encoded) AMR. This demonstrates that horizontal transfer of AMR directly affects epidemiological outcomes of globally important AMR pathogens and highlights the need for integration of genomic analyses into all areas of AMR research, surveillance and management.

  8. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia

    2018-05-23

    Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

  9. Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland.

    Science.gov (United States)

    Lanz, Roland; Kuhnert, Peter; Boerlin, Patrick

    2003-01-02

    Antimicrobial susceptibility testing was performed on a total of 581 clinical Escherichia coli isolates from diarrhea and edema disease in pigs, from acute mastitis in dairy cattle, from urinary tract infections in dogs and cats, and from septicemia in laying hens collected in Switzerland between 1999 and 2001. Among the 16 antimicrobial agents tested, resistance was most frequent for sulfonamides, tetracycline, and streptomycin. Isolates from swine presented significantly more resistance than those from the other animal species. The distribution of the resistance determinants for sulfonamides, tetracycline, and streptomycin was assessed by hybridization and PCR in resistant isolates. Significant differences in the distribution of resistance determinants for tetracycline (tetA, tetB) and sulfonamides (sulII) were observed between the isolates from swine and those from the other species. Resistance to sulfonamides could not be explained by known resistance mechanisms in more than a quarter of the sulfonamide-resistant and sulfonamide-intermediate isolates from swine, dogs and cats. This finding suggests that one or several new resistance mechanisms for sulfonamides may be widespread among E. coli isolates from these animal species. The integrase gene (intI) from class I integrons was detected in a large proportion of resistant isolates in association with the sulI and aadA genes, thus demonstrating the importance of integrons in the epidemiology of resistance in clinical E. coli isolates from animals.

  10. 77 FR 59156 - Antimicrobial Animal Drug Sales and Distribution Reporting; Extension of Comment Period

    Science.gov (United States)

    2012-09-26

    .... FDA-2012-N-0447] Antimicrobial Animal Drug Sales and Distribution Reporting; Extension of Comment... its regulations relating to records and reports for approved antimicrobial new animal drugs. The... obtaining additional data and information about the extent of antimicrobial drug use in food-producing...

  11. Antimicrobial and Antiradical Activity of Extracts Obtained from Leaves of Five Species of the Genus Bergenia: Identification of Antimicrobial Compounds.

    Science.gov (United States)

    Żbikowska, Beata; Franiczek, Roman; Sowa, Alina; Połukord, Grażyna; Krzyżanowska, Barbara; Sroka, Zbigniew

    2017-09-01

    An important focus of modern medicine is the search for new substances and strategies to combat infectious diseases, which present an increasing threat due to the growth of bacterial resistance to antibiotics. Another problem concerns free radicals, which in excess can cause several serious diseases. An alternative to chemical synthesis of antimicrobial and antiradical compounds is to find active substances in plant raw materials. We prepared extracts from leaves of five species of the genus Bergenia: B. purpurascens, B. cordifolia, B. ligulata, B. crassifolia, and B. ciliata. Antimicrobial and antiradical features of extracts and raw materials were assessed, and the quantities of phenolic compounds were determined. We also evaluated, using high-performance liquid chromatography, the amounts of arbutin and hydroquinone, compounds related to antimicrobial activity of these raw materials. The strongest antiradical properties were shown by leaves of B. crassifolia and B. cordifolia, the lowest by leaves of B. ciliata. The antiradical activity of extracts showed a strong positive correlation with the amount of phenols. All raw materials have significant antimicrobial properties. Among them, the ethyl acetate extracts were the most active. Antimicrobial activity very weakly correlated with the amount of arbutin, but correlated very strongly with the contents of both hydroquinone and phenolic compounds. Additional experiments using artificially prepared mixtures of phenolic compounds and hydroquinone allowed us to conclude that the most active antimicrobial substance is hydroquinone.

  12. Confronting species distribution model predictions with species functional traits.

    Science.gov (United States)

    Wittmann, Marion E; Barnes, Matthew A; Jerde, Christopher L; Jones, Lisa A; Lodge, David M

    2016-02-01

    Species distribution models are valuable tools in studies of biogeography, ecology, and climate change and have been used to inform conservation and ecosystem management. However, species distribution models typically incorporate only climatic variables and species presence data. Model development or validation rarely considers functional components of species traits or other types of biological data. We implemented a species distribution model (Maxent) to predict global climate habitat suitability for Grass Carp (Ctenopharyngodon idella). We then tested the relationship between the degree of climate habitat suitability predicted by Maxent and the individual growth rates of both wild (N = 17) and stocked (N = 51) Grass Carp populations using correlation analysis. The Grass Carp Maxent model accurately reflected the global occurrence data (AUC = 0.904). Observations of Grass Carp growth rate covered six continents and ranged from 0.19 to 20.1 g day(-1). Species distribution model predictions were correlated (r = 0.5, 95% CI (0.03, 0.79)) with observed growth rates for wild Grass Carp populations but were not correlated (r = -0.26, 95% CI (-0.5, 0.012)) with stocked populations. Further, a review of the literature indicates that the few studies for other species that have previously assessed the relationship between the degree of predicted climate habitat suitability and species functional traits have also discovered significant relationships. Thus, species distribution models may provide inferences beyond just where a species may occur, providing a useful tool to understand the linkage between species distributions and underlying biological mechanisms.

  13. On the Mass Distribution of Animal Species

    Science.gov (United States)

    Redner, Sidney; Clauset, Aaron; Schwab, David

    2009-03-01

    We develop a simple diffusion-reaction model to account for the broad and asymmetric distribution of adult body masses for species within related taxonomic groups. The model assumes three basic evolutionary features that control body mass: (i) a fixed lower limit that is set by metabolic constraints, (ii) a species extinction risk that is a weakly increasing function of body mass, and (iii) cladogenetic diffusion, in which daughter species have a slight tendency toward larger mass. The steady-state solution for the distribution of species masses in this model can be expressed in terms of the Airy function. This solution gives mass distributions that are in good agreement with data on 4002 terrestrial mammal species from the late Quaternary and 8617 extant bird species.

  14. Ensemble forecasting of species distributions.

    Science.gov (United States)

    Araújo, Miguel B; New, Mark

    2007-01-01

    Concern over implications of climate change for biodiversity has led to the use of bioclimatic models to forecast the range shifts of species under future climate-change scenarios. Recent studies have demonstrated that projections by alternative models can be so variable as to compromise their usefulness for guiding policy decisions. Here, we advocate the use of multiple models within an ensemble forecasting framework and describe alternative approaches to the analysis of bioclimatic ensembles, including bounding box, consensus and probabilistic techniques. We argue that, although improved accuracy can be delivered through the traditional tasks of trying to build better models with improved data, more robust forecasts can also be achieved if ensemble forecasts are produced and analysed appropriately.

  15. Antimicrobial activities of some Euphorbia species | Kirbag | African ...

    African Journals Online (AJOL)

    The antimicrobial activities of these extracts were examined on test microorganisms as follows: Staphylococcus aureus COWAN 1, Bacillus megaterium DSM 32, Proteus vulgaris FMC 1, Klebsiella pneumonia FMC 5, Escherichia coli ATCC 25922, Pseudomonas aeruginosa DSM 50071, Candida albicans FMC 17, Candida ...

  16. New trends in species distribution modelling

    Science.gov (United States)

    Zimmermann, Niklaus E.; Edwards, Thomas C.; Graham, Catherine H.; Pearman, Peter B.; Svenning, Jens-Christian

    2010-01-01

    Species distribution modelling has its origin in the late 1970s when computing capacity was limited. Early work in the field concentrated mostly on the development of methods to model effectively the shape of a species' response to environmental gradients (Austin 1987, Austin et al. 1990). The methodology and its framework were summarized in reviews 10–15 yr ago (Franklin 1995, Guisan and Zimmermann 2000), and these syntheses are still widely used as reference landmarks in the current distribution modelling literature. However, enormous advancements have occurred over the last decade, with hundreds – if not thousands – of publications on species distribution model (SDM) methodologies and their application to a broad set of conservation, ecological and evolutionary questions. With this special issue, originating from the third of a set of specialized SDM workshops (2008 Riederalp) entitled 'The Utility of Species Distribution Models as Tools for Conservation Ecology', we reflect on current trends and the progress achieved over the last decade.

  17. ESUSA: US endangered species distribution file

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J.; Calef, C.E.

    1979-10-01

    This report describes a file containing distribution data on endangered species of the United States of Federal concern pursuant to the Endangered Species Act of 1973. Included for each species are (a) the common name, (b) the scientific name, (c) the family, (d) the group (mammal, bird, etc.), (e) Fish and Wildlife Service (FWS) listing and recovery priorities, (f) the Federal legal status, (g) the geographic distribution by counties or islands, (h) Federal Register citations and (i) the sources of the information on distribution of the species. Status types are endangered, threatened, proposed, formally under review, candidate, deleted, and rejected. Distribution is by Federal Information Processing Standard (FIPS) county code and is of four types: designated critical habitat, present range, potential range, and historic range.

  18. Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated in Taiwan.

    Science.gov (United States)

    Yeh, Jih-Ching; Lo, Dan-Yuan; Chang, Shao-Kuang; Kuo, Hung-Chih

    2018-03-13

    Some members of the Brachyspira genus cause diseases such as swine dysentery (SD) and porcine intestinal (or colonic) spirochetosis. Severe economic losses are caused by decreased feed intake and increased feed conversion ratio, as well as costs associated with treatment and death. A loss of clinical efficacy of some antimicrobial agents authorized for treating SD has been observed in many countries. The aim of this study was to analyze the antimicrobial susceptibility of Brachyspira isolated from Taiwan and to investigate the mechanism of decreased susceptibility to macrolides. A total of 55 Brachyspira isolates obtained from the grower-finisher period were evaluated in this study. These isolates included B. hyodysenteriae (n = 37), B. murdochii (n = 11), B. pilosicoli (n = 5), B. intermedia (n = 1), and B. innocens (n = 1). Antimicrobial susceptibility testing was performed to examine 12 selected antimicrobial agents. The results showed that the 50% and 90% minimum inhibitory concentration (MIC) values of the tested macrolides were all >256 μg/ml. The MIC 50 of lincomycin, tiamulin, carbadox, olaquindox, ampicillin, amoxicillin, doxycycline, oxytetracycline, and gentamicin were 32, 1, ≤0.125, ≤0.125, 0.5, 0.25, 2, 2, and 2 μg/ml. The genetic basis of the decreased susceptibility to tylosin and lincomycin in Brachyspira spp. was investigated and the results showed a possible connection to the mutations at position A2058 and G2032 of the 23S rRNA gene. These findings demonstrated that, in Taiwan, there may be a decrease in susceptibility of Brachyspira spp. to antimicrobials commonly used for the treatment of SD.

  19. Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated from Swine Herds in the United States

    OpenAIRE

    Mirajkar, Nandita S.; Davies, Peter R.; Gebhart, Connie J.

    2016-01-01

    Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered “Brachyspira hampsonii,” have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determi...

  20. Distribution of crayfish species in Hungarian waters

    NARCIS (Netherlands)

    Mercédesz, Ludányi; Peeters, E.T.H.M.; Kiss, B.; Roessink, I.

    2016-01-01

    Three native crayfish species, i.e.~Astacus astacus, Astacus leptodactylus and Austropotamobius torrentium, occur in Hungary. Lately, however, non-indigenous crustaceans have also invaded the country Their most recent distribution and impact on the occurrences of the native species is not clear.

  1. Finessing atlas data for species distribution models

    NARCIS (Netherlands)

    Niamir, A.; Skidmore, A.K.; Toxopeus, A.G.; Munoz, A.R.; Real, R.

    2011-01-01

    Aim The spatial resolution of species atlases and therefore resulting model predictions are often too coarse for local applications. Collecting distribution data at a finer resolution for large numbers of species requires a comprehensive sampling effort, making it impractical and expensive. This

  2. Incorporating Context Dependency of Species Interactions in Species Distribution Models.

    Science.gov (United States)

    Lany, Nina K; Zarnetske, Phoebe L; Gouhier, Tarik C; Menge, Bruce A

    2017-07-01

    Species distribution models typically use correlative approaches that characterize the species-environment relationship using occurrence or abundance data for a single species. However, species distributions are determined by both abiotic conditions and biotic interactions with other species in the community. Therefore, climate change is expected to impact species through direct effects on their physiology and indirect effects propagated through their resources, predators, competitors, or mutualists. Furthermore, the sign and strength of species interactions can change according to abiotic conditions, resulting in context-dependent species interactions that may change across space or with climate change. Here, we incorporated the context dependency of species interactions into a dynamic species distribution model. We developed a multi-species model that uses a time-series of observational survey data to evaluate how abiotic conditions and species interactions affect the dynamics of three rocky intertidal species. The model further distinguishes between the direct effects of abiotic conditions on abundance and the indirect effects propagated through interactions with other species. We apply the model to keystone predation by the sea star Pisaster ochraceus on the mussel Mytilus californianus and the barnacle Balanus glandula in the rocky intertidal zone of the Pacific coast, USA. Our method indicated that biotic interactions between P. ochraceus and B. glandula affected B. glandula dynamics across >1000 km of coastline. Consistent with patterns from keystone predation, the growth rate of B. glandula varied according to the abundance of P. ochraceus in the previous year. The data and the model did not indicate that the strength of keystone predation by P. ochraceus varied with a mean annual upwelling index. Balanus glandula cover increased following years with high phytoplankton abundance measured as mean annual chlorophyll-a. M. californianus exhibited the same

  3. Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated from Swine Herds in the United States.

    Science.gov (United States)

    Mirajkar, Nandita S; Davies, Peter R; Gebhart, Connie J

    2016-08-01

    Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered "Brachyspira hampsonii," have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determine the antimicrobial susceptibility trends of four Brachyspira species originating from U.S. swine herds and to investigate their associations with the bacterial species, genotypes, and epidemiological origins of the isolates. We evaluated the susceptibility of B. hyodysenteriae, B. hampsonii, Brachyspira pilosicoli, and Brachyspira murdochii to tiamulin, valnemulin, doxycycline, lincomycin, and tylosin by broth microdilution and that to carbadox by agar dilution. In general, Brachyspira species showed high susceptibility to tiamulin, valnemulin, and carbadox, heterogeneous susceptibility to doxycycline, and low susceptibility to lincomycin and tylosin. A trend of decreasing antimicrobial susceptibility by species was observed (B. hampsonii > B. hyodysenteriae > B. murdochii > B. pilosicoli). In general, Brachyspira isolates from the United States were more susceptible to these antimicrobials than were isolates from other countries. Decreased antimicrobial susceptibility was associated with the genotype, stage of production, and production system from which the isolate originated, which highlights the roles of biosecurity and husbandry in disease prevention and control. Finally, this study also highlights the urgent need for Clinical and Laboratory Standards Institute-approved clinical breakpoints for Brachyspira species, to facilitate informed therapeutic and control strategies. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  4. Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated from Swine Herds in the United States

    Science.gov (United States)

    Mirajkar, Nandita S.; Davies, Peter R.

    2016-01-01

    Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered “Brachyspira hampsonii,” have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determine the antimicrobial susceptibility trends of four Brachyspira species originating from U.S. swine herds and to investigate their associations with the bacterial species, genotypes, and epidemiological origins of the isolates. We evaluated the susceptibility of B. hyodysenteriae, B. hampsonii, Brachyspira pilosicoli, and Brachyspira murdochii to tiamulin, valnemulin, doxycycline, lincomycin, and tylosin by broth microdilution and that to carbadox by agar dilution. In general, Brachyspira species showed high susceptibility to tiamulin, valnemulin, and carbadox, heterogeneous susceptibility to doxycycline, and low susceptibility to lincomycin and tylosin. A trend of decreasing antimicrobial susceptibility by species was observed (B. hampsonii > B. hyodysenteriae > B. murdochii > B. pilosicoli). In general, Brachyspira isolates from the United States were more susceptible to these antimicrobials than were isolates from other countries. Decreased antimicrobial susceptibility was associated with the genotype, stage of production, and production system from which the isolate originated, which highlights the roles of biosecurity and husbandry in disease prevention and control. Finally, this study also highlights the urgent need for Clinical and Laboratory Standards Institute-approved clinical breakpoints for Brachyspira species, to facilitate informed therapeutic and control strategies. PMID:27252458

  5. Forms and genesis of species abundance distributions

    Directory of Open Access Journals (Sweden)

    Evans O. Ochiaga

    2015-12-01

    Full Text Available Species abundance distribution (SAD is one of the most important metrics in community ecology. SAD curves take a hollow or hyperbolic shape in a histogram plot with many rare species and only a few common species. In general, the shape of SAD is largely log-normally distributed, although the mechanism behind this particular SAD shape still remains elusive. Here, we aim to review four major parametric forms of SAD and three contending mechanisms that could potentially explain this highly skewed form of SAD. The parametric forms reviewed here include log series, negative binomial, lognormal and geometric distributions. The mechanisms reviewed here include the maximum entropy theory of ecology, neutral theory and the theory of proportionate effect.

  6. Applications of species distribution modeling to paleobiology

    DEFF Research Database (Denmark)

    Svenning, Jens-Christian; Fløjgaard, Camilla; Marske, Katharine Ann

    2011-01-01

    -Pleistocene megafaunal extinctions, past community assembly, human paleobiogeography, Holocene paleoecology, and even deep-time biogeography (notably, providing insights into biogeographic dynamics >400 million years ago). We discuss important assumptions and uncertainties that affect the SDM approach to paleobiology......Species distribution modeling (SDM: statistical and/or mechanistic approaches to the assessment of range determinants and prediction of species occurrence) offers new possibilities for estimating and studying past organism distributions. SDM complements fossil and genetic evidence by providing (i......) quantitative and potentially high-resolution predictions of the past organism distributions, (ii) statistically formulated, testable ecological hypotheses regarding past distributions and communities, and (iii) statistical assessment of range determinants. In this article, we provide an overview...

  7. Antimicrobial activities of three species of family mimosaceae.

    Science.gov (United States)

    Mahmood, Adeel; Mahmood, Aqeel; Qureshi, Rizwana Aleem

    2012-01-01

    The antimicrobial activities of crude methanolic extract of leaves of Acacia nilotica L., Albizia lebbeck L. and Mimosa himalayana Gamble belonging to family mimosaceae were investigated in this research work. Antibacterial activity was studied by agar well diffusion method against one gram-positive Bacillus subtilis and three gram-negative Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumonia. Crude extract of all plants showed best activity against gram-negative bacterial strains while minor inhibition zones were found against gram positive bacterial strains. Antifungal activity of crude plant extract was screened by agar tube dilution method against Aspergillus nigar and Aspergillus flavus. These results showed that these plants extracts have potential against bacterias, while against fungi their activity is not much effective.

  8. The distribution of animal antimicrobials in British Columbia for over-the-counter and veterinary sales, 2012 to 2014.

    Science.gov (United States)

    Radke, Brian R

    2018-03-01

    Canadian Animal Health Institute (CAHI) data are used for provincial, national, and international comparisons of Canadian animal antimicrobial use. The objectives of this paper were to: i) use CAHI and British Columbia (BC) antimicrobial distribution data to group BC antimicrobial sales into the following BC retail distribution channels: over-the-counter retail outlets, livestock and poultry feed mills, aquaculture feed mills, livestock and poultry veterinarians, and companion animal veterinarians; and ii) to validate the CAHI BC distribution data and BC's antimicrobial distribution data from 2012 to 2014. Annual total antimicrobial distribution and distribution by antimicrobial class were presented for each distribution channel. The distribution of medically important antimicrobials for production animals was validated, the distribution of ionophores was not. A lack of data precluded any attempt to validate the distribution of antimicrobials for companion animals. Each distribution channel typically experienced substantial fluctuations in total antimicrobial use and use by antibiotic class at least once over the 3-year period. The validated data are useful for evidence-based analysis of a proposed Canadian policy requiring a veterinary prescription for all medically important antimicrobials.

  9. Exploring similarities among many species distributions

    Science.gov (United States)

    Simmerman, Scott; Wang, Jingyuan; Osborne, James; Shook, Kimberly; Huang, Jian; Godsoe, William; Simons, Theodore R.

    2012-01-01

    Collecting species presence data and then building models to predict species distribution has been long practiced in the field of ecology for the purpose of improving our understanding of species relationships with each other and with the environment. Due to limitations of computing power as well as limited means of using modeling software on HPC facilities, past species distribution studies have been unable to fully explore diverse data sets. We build a system that can, for the first time to our knowledge, leverage HPC to support effective exploration of species similarities in distribution as well as their dependencies on common environmental conditions. Our system can also compute and reveal uncertainties in the modeling results enabling domain experts to make informed judgments about the data. Our work was motivated by and centered around data collection efforts within the Great Smoky Mountains National Park that date back to the 1940s. Our findings present new research opportunities in ecology and produce actionable field-work items for biodiversity management personnel to include in their planning of daily management activities.

  10. Geographic distribution of wild potato species

    NARCIS (Netherlands)

    Hijmans, R.J.; Spooner, D.M.

    2001-01-01

    The geographic distribution of wild potatoes (Solanaceae sect. Petota) was analyzed using a database of 6073 georeferenced observations. Wild potatoes occur in 16 countries, but 88% of the observations are from Argentina, Bolivia, Mexico, and Peru. Most species are rare and narrowly endemic: for 77

  11. Frequency and Antimicrobial Susceptibility Pattern of Acinetobacter Species Isolated from Pus and Pus Swab Specimens

    International Nuclear Information System (INIS)

    Fayyaz, M.; Akbar, N.; Khan, I. U.; Hussain, A.; Ali, S.; Mirza, I. A.

    2015-01-01

    Objective: To evaluate the frequency and antimicrobial susceptibility pattern of Acinetobacter species isolated from pus and pus swab specimens at a tertiary care setting. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from July 2008 to July 2012. Methodology: Data regarding positive culture and antimicrobial sensitivity pattern was retrieved from the pus and pus swab culture records of the Microbiology Department, AFIP, Rawalpindi. Only those pus and pus swab specimens which yielded the growth of Acinetobacter species were included in the study. Results:Out of 2781, 1848 were of pure pus while 933 were pus swab specimens. Out of 2538 culture positive isolates, 276 (10.9 percentage) were identified as Acinetobacterspecies. Among 276 Acinetobacter species, 245 (88.8 percentage) were Acinetobacter baumannii and 31 (11.2 percentage) were Acinetobacter johnsonii. Male/female ratio of the affected patients was 5.6:1. Doxycycline was the most sensitive antibiotic to which 45 percentage of the tested isolates were sensitive. Sensitivity to all other antimicrobials was 15 percentage or less. Conclusion: About 11 percentage of soft tissue and wound infections are caused by Acinetobacter species in our set up particularly in male. Doxycycline was the most sensitive antibiotic. Sensitivity to all other antimicrobials was 15 percentage or less. In vitro sensitivity to carbapenems is very low. (author)

  12. Antimicrobial Activity of Various Plant Extracts on Pseudomonas Species Associated with Spoilage of Chilled Fish

    Directory of Open Access Journals (Sweden)

    Osan Bahurmiz

    2016-11-01

    Full Text Available The antimicrobial activity of various plant extracts on Pseudomonas bacteria isolated from spoiled chilled tilapia (Oreochromis sp. was evaluated in this study. In the first stage of this study, red tilapia was subjected to chilled storage (4°C for 3 weeks, and spoilage bacteria were isolated and identified from the spoiled fish. Pseudomonas was the dominant bacteria isolated from the spoiled fish and further identification revealed that P. putida, P. fluorescens and Pseudomonas spp. were the main species of this group. In the second stage, methanolic extracts of 15 selected plant species were screened for their antimicrobial activity, by agar disc diffusion method, against the Pseudomonas isolates. Results indicated that most of the extracts had different degrees of activity against the bacterial isolates. The strongest activity was exhibited by bottlebrush flower (Callistemon viminalis extract. This was followed by extracts from guava bark (Psidium guajava and henna leaf (Lawsonia inermis. Moderate antimicrobial activities were observed in extracts of clove (Syzygium aromaticum, leaf and peel of tamarind (Tamarindus indica, cinnamon bark (Cinnamomum zeylanicum, wild betel leaf (Piper sarmentosum and fresh thyme (Thymus spp.. Weak or no antimicrobial activity was observed from the remaining extracts. The potential antimicrobial activity shown by some plant extracts in this study could significantly contribute to the fish preservation.

  13. Prevalence and Antimicrobial Resistance of Enterococcus Species: A Hospital-Based Study in China

    Directory of Open Access Journals (Sweden)

    Wei Jia

    2014-03-01

    Full Text Available Objective: to investigate the prevalence and antimicrobial resistance of Enterococcus species isolated from a university hospital, and explore the mechanisms underlying the antimicrobial resistance, so as to provide clinical evidence for the inappropriate clinical use of antimicrobial agents and the control and prevention of enterococcal infections. Methods: a total of 1,157 enterococcal strains isolated from various clinical specimens from January 2010 to December 2012 in the General Hospital of Ningxia Medical University were identified to species level with a VITEK-2 COMPACT fully automated microbiological system, and the antimicrobial susceptibility of Enterococcus species was determined using the Kirby-Bauer disc diffusion method. The multiple-drug resistant enterococcal isolates were screened from the clinical isolates of Enterococcus species from the burns department. The minimal inhibitory concentration (MIC of Enterococcus species to the three fluoroquinolones, including ciprofloxacin, gatifloxacin and levofloxacin was determined with the agar dilution method, and the changes in the MIC of Enterococcus species to the three fluoroquinolones following reserpine treatment were evaluated. The β-lactam, aminoglycoside, tetracycline, macrolide, glycopeptide resistance genes and the efflux pump emeA genes were detected in the enterococcal isolates using a polymerase chain reaction (PCR assay. Results: the 1,157 clinical isolates of Enterococcus species included 679 E. faecium isolates (58.7%, 382 E. faecalis isolates (33%, 26 E. casseliflavus isolates (2.2%, 24 E. avium isolates (2.1%, and 46 isolates of other Enterococcus species (4%. The prevalence of antimicrobial resistance varied significantly between E. faecium and E. faecalis, and ≤1.1% of these two Enterococcus species were found to be resistant to vancomycin, teicoplanin or linezolid. In addition, the Enterococcus species isolated from different departments of the hospital

  14. Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

    OpenAIRE

    Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H

    1991-01-01

    The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the fi...

  15. Antimicrobial susceptibility among clinical Nocardia species identified by multilocus sequence analysis.

    Science.gov (United States)

    McTaggart, Lisa R; Doucet, Jennifer; Witkowska, Maria; Richardson, Susan E

    2015-01-01

    Antimicrobial susceptibility patterns of 112 clinical isolates, 28 type strains, and 9 reference strains of Nocardia were determined using the Sensititre Rapmyco microdilution panel (Thermo Fisher, Inc.). Isolates were identified by highly discriminatory multilocus sequence analysis and were chosen to represent the diversity of species recovered from clinical specimens in Ontario, Canada. Susceptibility to the most commonly used drug, trimethoprim-sulfamethoxazole, was observed in 97% of isolates. Linezolid and amikacin were also highly effective; 100% and 99% of all isolates demonstrated a susceptible phenotype. For the remaining antimicrobials, resistance was species specific with isolates of Nocardia otitidiscaviarum, N. brasiliensis, N. abscessus complex, N. nova complex, N. transvalensis complex, N. farcinica, and N. cyriacigeorgica displaying the traditional characteristic drug pattern types. In addition, the antimicrobial susceptibility profiles of a variety of rarely encountered species isolated from clinical specimens are reported for the first time and were categorized into four additional drug pattern types. Finally, MICs for the control strains N. nova ATCC BAA-2227, N. asteroides ATCC 19247(T), and N. farcinica ATCC 23826 were robustly determined to demonstrate method reproducibility and suitability of the commercial Sensititre Rapmyco panel for antimicrobial susceptibility testing of Nocardia spp. isolated from clinical specimens. The reported values will facilitate quality control and standardization among laboratories. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Investigating the Phytochemicals and Antimicrobial Properties of Three Sedge (Cyperaceae Species

    Directory of Open Access Journals (Sweden)

    Tiwalade Adeyemi ADENIYI

    2014-09-01

    Full Text Available In order to evaluate the medicinal value of notorious sedge weeds, three species:Cyperus esculentus, Cyperus rotundus and Mariscus alternifolius were investigated for their phytochemical constituents and antimicrobial properties. Preliminary qualitative phytochemical constituents and in vitro antimicrobial activities were evaluated against four fungi species: Aspergillus niger, Aspergillus fumigatus, Penicillium chrysogenum and Candida albicans, and three bacteria species: Escherichia coli,Salmonella typhi and Staphylococcus aureus. Two solvents, water and ethanol, were used to produce the extracts and were screened for their antimicrobial activity. Antimicrobial activity evaluation of the extracts against pathogens was carried out at 100 mg/ml concentration by Disc Diffusion method for fungi, Disc Diffusion and Agar Well Diffusion methods for bacteria. Observed activities were related to standard antibiotics, antifungal and antibacterial, which served as controls. Phytochemically, the plant extracts showed the presence of carbohydrates, flavonoids, ketose sugars, steroids, reducing sugars and tannins. The ethanolic extract of C. rotundus exhibited the highest activity against A. niger, E. coli and S. aureus. No extract was active against C. albicans. From these findings, it was concluded that C. rotundus is a potential source of bioactive compounds for new drugs upon isolation and purification for treating infections caused by these pathogens.

  17. Antimicrobial susceptibility patterns of Ureaplasma species and Mycoplasma hominis in pregnant women.

    Science.gov (United States)

    Redelinghuys, Mathys J; Ehlers, Marthie M; Dreyer, Andries W; Lombaard, Hennie A; Kock, Marleen M

    2014-03-28

    Genital mycoplasmas colonise up to 80% of sexually mature women and may invade the amniotic cavity during pregnancy and cause complications. Tetracyclines and fluoroquinolones are contraindicated in pregnancy and erythromycin is often used to treat patients. However, increasing resistance to common antimicrobial agents is widely reported. The purpose of this study was to investigate antimicrobial susceptibility patterns of genital mycoplasmas in pregnant women. Self-collected vaginal swabs were obtained from 96 pregnant women attending an antenatal clinic in Gauteng, South Africa. Specimens were screened with the Mycofast Revolution assay for the presence of Ureaplasma species and Mycoplasma hominis. The antimicrobial susceptibility to levofloxacin, moxifloxacin, erythromycin, clindamycin and tetracycline were determined at various breakpoints. A multiplex polymerase chain reaction assay was used to speciate Ureaplasma positive specimens as either U. parvum or U. urealyticum. Seventy-six percent (73/96) of specimens contained Ureaplasma spp., while 39.7% (29/73) of Ureaplasma positive specimens were also positive for M. hominis. Susceptibilities of Ureaplasma spp. to levofloxacin and moxifloxacin were 59% (26/44) and 98% (43/44) respectively. Mixed isolates (Ureaplasma species and M. hominis) were highly resistant to erythromycin and tetracycline (both 97% resistance). Resistance of Ureaplasma spp. to erythromycin was 80% (35/44) and tetracycline resistance was detected in 73% (32/44) of Ureaplasma spp. Speciation indicated that U. parvum was the predominant Ureaplasma spp. conferring antimicrobial resistance. Treatment options for genital mycoplasma infections are becoming limited. More elaborative studies are needed to elucidate the diverse antimicrobial susceptibility patterns found in this study when compared to similar studies. To prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is

  18. Distribution of Vulpia species (Poaceae in Poland

    Directory of Open Access Journals (Sweden)

    Ludwik Frey

    2011-01-01

    Full Text Available The distribution of four species of the genus Vulpia [V. myuros (L. C.C. Gmel., V. bromoides (L. S.F. Gray, V. ciliata Dumort. and V. geniculata (L. Link] reported in Poland has been studied. Currently, V. myuros and especially V. bromoides are very rare species, and their greatest concentration can be found only in the Lower Silesia region. The number of their localities decreased after 1950 and it seems resonable to include both species in the "red list" of threatened plants in Poland: V. myuros in the EN category, V. bromoides in the CR category. V. ciliata and V. geniculata are very rare ephemerophytes and their localities not confirmed during ca 60 years are of historical interest only.

  19. Incorporating uncertainty in predictive species distribution modelling.

    Science.gov (United States)

    Beale, Colin M; Lennon, Jack J

    2012-01-19

    Motivated by the need to solve ecological problems (climate change, habitat fragmentation and biological invasions), there has been increasing interest in species distribution models (SDMs). Predictions from these models inform conservation policy, invasive species management and disease-control measures. However, predictions are subject to uncertainty, the degree and source of which is often unrecognized. Here, we review the SDM literature in the context of uncertainty, focusing on three main classes of SDM: niche-based models, demographic models and process-based models. We identify sources of uncertainty for each class and discuss how uncertainty can be minimized or included in the modelling process to give realistic measures of confidence around predictions. Because this has typically not been performed, we conclude that uncertainty in SDMs has often been underestimated and a false precision assigned to predictions of geographical distribution. We identify areas where development of new statistical tools will improve predictions from distribution models, notably the development of hierarchical models that link different types of distribution model and their attendant uncertainties across spatial scales. Finally, we discuss the need to develop more defensible methods for assessing predictive performance, quantifying model goodness-of-fit and for assessing the significance of model covariates.

  20. Antimicrobial potential of two traditional herbometallic drugs against certain pathogenic microbial species.

    Science.gov (United States)

    Wijenayake, A U; Abayasekara, C L; Pitawala, H M T G A; Bandara, B M R

    2016-09-15

    Mineral based preparations are widely used for centuries as antimicrobial agents. However, the efficacy and the mode of action of mineral based preparations are uncertain due to the insufficient antimicrobial studies. Arogyawardhana Vati (AV) and Manikya Rasa (MR) are such two Rasashastra herbo-minerallic drugs commonly in India and other countries in South Asia. Despite of their well known traditional use of skin diseases, reported antimicrobial and mineralogical studies are limited. Therefore, in this study antimicrobial activities of the drugs and their organic, inorganic fractions were evaluated against Pseudomonas aeruginosa, Escherischia coli, Staphylococcus aureus, Methecilline Resistance Staphylococcus aureus - MRSA and Candida albicans. Antimicrobial activity of the drugs, their inorganic residues and organic extracts were determined using four assay techniques viz agar well diffusion, modified well diffusion, Miles and Misra viable cell counting and broth turbidity measurements. Mineralogical constituents of the drugs were determined using X-ray diffraction, while total cation constituents and water soluble cation constituents were determined using inductively coupled plasma-mass spectrometer and the atomic absorption spectrophotometer respectively. Thermogravimetric analysis was used to determine the weight percentages of organic and inorganic fraction of the drugs. Particle sizes of the drugs were determined using the particle size analyzer. AV and MR drugs showed antibacterial activity against both gram positive and gram negative bacterial species when analyzed separately. Inorganic residues of the drugs and organic extracts showed activity at least against two or more bacterial species tested. All tested components were inactive against C. albicans. Common mineral constituents of drugs are cinnabar, biotite and Fe-rich phases. Drugs were rich in essential elements such as Na, K, Ca, Mg and Fe and toxic elements such as Zn, Cu and As. However, the

  1. Inhibitory effects of antimicrobial agents against Fusarium species.

    Science.gov (United States)

    Kawakami, Hideaki; Inuzuka, Hiroko; Hori, Nobuhide; Takahashi, Nobumichi; Ishida, Kyoko; Mochizuki, Kiyofumi; Ohkusu, Kiyofumi; Muraosa, Yasunori; Watanabe, Akira; Kamei, Katsuhiko

    2015-08-01

    We investigated the inhibitory effects of antibacterial, biocidal, and antifungal agents against Fusarium spp. Seven Fusarium spp: four F. falciforme (Fusarium solani species complex), one Fusarium spp, one Fusarium spp. (Fusarium incarnatum-equiseti species complex), and one F. napiforme (Gibberella fujikuroi species complex), isolated from eyes with fungal keratitis were used in this study. Their susceptibility to antibacterial agents: flomoxef, imipenem, gatifloxacin, levofloxacin, moxifloxacin, gentamicin, tobramycin, and Tobracin® (contained 3,000 μg/ml of tobramycin and 25 μg/ml of benzalkonium chloride (BAK), a biocidal agent: BAK, and antifungal agents: amphotericin B, pimaricin (natamycin), fluconazole, itraconazole, miconazole, voriconazole, and micafungin, was determined by broth microdilution tests. The half-maximal inhibitory concentration (IC50), 100% inhibitory concentration (IC100), and minimum inhibitory concentration (MIC) against the Fusarium isolates were determined. BAK had the highest activity against the Fusarium spp. except for the antifungal agents. Three fluoroquinolones and two aminoglycosides had inhibitory effects against the Fusarium spp. at relatively high concentrations. Tobracin® had a higher inhibitory effect against Fusarium spp. than tobramycin alone. Amphotericin B had the highest inhibitory effect against the Fusarium spp, although it had different degrees of activity against each isolate. Our findings showed that fluoroquinolones, aminoglycosides, and BAK had some degree of inhibitory effect against the seven Fusarium isolates, although these agents had considerably lower effect than amphotericin B. However, the inhibitory effects of amphotericin B against the Fusarium spp. varied for the different isolates. Further studies for more effective medications against Fusarium, such as different combinations of antibacterial, biocidal, and antifungal agents are needed. © The Author 2015. Published by Oxford University Press on

  2. Node-based analysis of species distributions

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Rahbek, Carsten; Fjeldså, Jon

    2014-01-01

    overrepresentation score (SOS) and the geographic node divergence (GND) score, which together combine ecological and evolutionary patterns into a single framework and avoids many of the problems that characterize community phylogenetic methods in current use.This approach goes through each node in the phylogeny...... with case studies on two groups with well-described biogeographical histories: a local-scale community data set of hummingbirds in the North Andes, and a large-scale data set of the distribution of all species of New World flycatchers. The node-based analysis of these two groups generates a set...... of intuitively interpretable patterns that are consistent with current biogeographical knowledge.Importantly, the results are statistically tractable, opening many possibilities for their use in analyses of evolutionary, historical and spatial patterns of species diversity. The method is implemented...

  3. Attenuation of species abundance distributions by sampling

    Science.gov (United States)

    Shimadzu, Hideyasu; Darnell, Ross

    2015-01-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  4. MORPHO-CHEMICAL DESCRIPTION AND ANTIMICROBIAL ACTIVITY OF DIFFERENT OCIMUM SPECIES

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    KAKARAPARTHI PANDU SASTRY

    2012-12-01

    Full Text Available Basil is a popular medicinal and culinary herb, and its essential oils have been used extensively for many years in food products, perfumery, dental and oral products. Basil essential oils and their principal constituents were found to exhibit antimicrobial activity against a wide range of Gram-negative and Gram-positive bacteria, yeast, and mould. The essential oils obtained from aerial parts of three different species of Ocimum comprising twenty one germplasm lines were investigated for their essential oil composition and antimicrobial activity during 2010. Essential oils from seventeen germplasm lines in Ocimum basilicum and two each in Ocimum tenuiflorum and Ocimum gratissimum were investigated for anti-microbial activity against four bacterial strains (Staphylococcus aureus, Bacillus sps., Escherichia coli and Pseudomonas aeruginosa. The morpho-chemotypes exhibited wide variability for morphological and chemical traits. Anti-bacterial activity was found to be high for Staphylococcus aureus, moderate for Escherichia coli, low for Bacillus and Pseudomonas aeruginosa was highly resistant. The essential oils of Pale Green-Broad Leaves (O. basilicum and CIM Ayu (O. gratissimum exhibited significant antibacterial activity against both S. aureus and E. coli signifying them promising for anti-bacterial activity. No relationship was observed between chemotype specificity and anti-bacterial activity, indicating that apart from major components of essential oil, minor components and other factors may be responsible for anti-microbial activities.

  5. Evaluation of antimicrobial and anti-inflammatory activities of seed extracts from six Nigella species.

    Science.gov (United States)

    Landa, Premysl; Marsik, Petr; Havlik, Jaroslav; Kloucek, Pavel; Vanek, Tomas; Kokoska, Ladislav

    2009-04-01

    Seed extracts from six species of the genus Nigella (Family Ranunculaceae)-Nigella arvensis, Nigella damascena, Nigella hispanica, Nigella nigellastrum, Nigella orientalis, and Nigella sativa-obtained by successive extraction with n-hexane, chloroform, and methanol, were tested for their antimicrobial activity against 10 strains of pathogenic bacteria and yeast using the microdilution method as well as for anti-inflammatory properties by in vitro cyclooxygenase (COX)-1 and COX-2 assay. Chemical characterization of active extracts was carried out including free and fixed fatty acid analysis. Comparison of antimicrobial activity showed that N. arvensis chloroform extract was the most potent among all species tested, inhibiting Gram-positive bacterial and yeast strains with minimum inhibitory concentration (MIC) values ranging from 0.25 to 1 mg/mL. With the exception of selective inhibitory action of n-hexane extract of N. orientalis on growth of Bacteroides fragilis (MIC = 0.5 mg/mL), we observed no antimicrobial activity for other Nigella species. Anti-inflammatory screening revealed that N. sativa, N. orientalis, N. hispanica, N. arvensis n-hexane, and N. hispanica chloroform extracts had strong inhibitory activity (more than 80%) on COX-1 and N. orientalis, N. arvensis, and N. hispanica n-hexane extracts were most effective against COX-2, when the concentration of extracts was 100 microg/mL in both COX assays. In conclusion, N. arvensis, N. orientalis, and N. hispanica seeds, for the first time examined for antimicrobial and anti-inflammatory effects, revealed their significant activity in one or both assays.

  6. Gridded Species Distribution, Version 1: Global Amphibians Presence Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Amphibians Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of amphibian species distribution...

  7. A biogeographical perspective on species abundance distributions

    DEFF Research Database (Denmark)

    Matthews, Thomas J.; Borges, Paulo A. V.; de Azevedo, Eduardo Brito

    2017-01-01

    It has become increasingly recognized that multiple processes can generate similar shapes of species abundance distributions (SADs), with the result that the fit of a given SAD model cannot unambiguously provide evidence in support of a given theory or model. An alternative approach to comparing...... the fit of different SAD models to data from a single site is to collect abundance data from a variety of sites, and then build models to analyse how different SAD properties (e.g. form, skewness) vary with different predictor variables. Such a biogeographical approach to SAD research is potentially very...... revealing, yet there has been a general lack of interest in SADs in the biogeographical literature. In this Perspective, we address this issue by highlighting findings of recent analyses of SADs that we consider to be of intrinsic biogeographical interest. We use arthropod data drawn from the Azorean...

  8. Traditional medicine in Sakarya province (Turkey) and antimicrobial activities of selected species.

    Science.gov (United States)

    Uzun, Ergin; Sariyar, Günay; Adsersen, Anne; Karakoc, Berna; Otük, Gülten; Oktayoglu, Ercan; Pirildar, Sevda

    2004-12-01

    Traditional medicine in North-West of Turkey (Sakarya province) were studied during a 2 months field study by interviewing local informants from several villages. Plant species used to treat infections were tested for antimicrobial activity. Information was collected for 46 plant species from 30 families and for 5 animal species. Twenty four of the plant species were cultivated. Most used families were Asteraceae, Cucurbitaceae, Lamiaceae and Rosaceae and the most used plants were Artemisia absinthium, Equisetum telmateia, Lavandula stoechas, Melissa officinalis, Tussilago farfara and Urtica dioica. A total of 139 medicinal uses were obtained. Plants are used mainly for infectious diseases (18%), for neurological and psychological disorders (13.7%), cardiovascular disorders (13%), skin disorders (12.2%) and respiratory disorders (10.1%). Extracts were tested in vitro for antimicrobial activity against Staphylococcus aureus ATCC 65538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumonia ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis and Candida albicans ATCC 10231, using microbroth dilution technique according to National Committee for Clinical Laboratory Standards (NCCLS). This research showed that Arum maculatum, Datura stramonium, Geranium asphodeloides and Equisetum telmateia petroleum ether extracts had MIC values of 39.1 microg/ml, 78.1 microg/ml, 78.1 microg/ml and 39.1 microg/ml, respectively against Staphylococcus epidermidis. Datura stramonium petroleum ether extract had a MIC value of 39.1 microg/ml against Escherichia coli and Trachystemon orientalis ethanol extract had a MIC value of 39.1 microg/ml against Escherichia coli. The antimicrobial activity of Arum maculatum, Equisetum telmateia, Geranium asphodeloides, Plantago intermedia, Senecio vulgaris and Trachystemon orientalis has been reported here for the first time.

  9. Distribution and antimicrobial potential of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L.

    Science.gov (United States)

    Mishra, Vineet Kumar; Singh, Garima; Passari, Ajit Kumar; Yadav, Mukesh Kumar; Gupta, Vijai Kumar; Singh, Bhim Pratap

    2016-03-01

    Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L. was studied and 91 isolates belonging to 18 genera were recovered. The isolates were distributed to sordariomycetes (62.63%), dothideomycetes (19.78%), eurotiomycetes (7.69%), zygomycetes (4.19%), agaricomycetes (1.09%), and mycelia sterilia (4.39%). Based on colony morphology and examination of spores, the isolates were classified into 18 taxa, of which Colletotrichum, Phomopsis and Phoma were dominant, their relative frequencies were 23.07%, 17.58% and 12.08% respectively. The colonization rate of endophytic fungi was determined and found to be significantly higher in leaf segments (50.76%), followed by root (41.53%) and stem tissues (27.69%). All the isolates were screened for antimicrobial activity and revealed that 26.37% endophytic fungi were active against one or more pathogens. Twenty four isolates showing significant antimicrobial activity were identified by sequencing the ITS1-5.8S-ITS2 region of rRNA gene. Results indicated that endophytic fungi associated with leaf were functionally versatile as they showed antimicrobial activity against most of the tested pathogens. The endophytic fungi Diaporthe phaseolorum var. meridionalis (KF193982) inhibited all the tested bacterial pathogens, whereas, Penicillium chermesinum (KM405640) displayed most significant antifungal activity. This seems to be the first hand report to understand the distribution and antimicrobial ability of endophytic fungi from ethno-medicinal plant M. malabathricum.

  10. Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

    Directory of Open Access Journals (Sweden)

    Débora Paula Ferreira

    2010-10-01

    Full Text Available Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110 and non-diarrheic (n=65 fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic, and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.

  11. Potential enterotoxicity and antimicrobial resistance pattern of Aeromonas species isolated from pet turtles and their environment.

    Science.gov (United States)

    Wimalasena, S H M P; Shin, Gee-Wook; Hossain, Sabrina; Heo, Gang-Joon

    2017-05-23

    To investigate the potential enterotoxicity and antimicrobial resistance of aeromonads from pet turtles as a risk for human infection, one hundred and two Aeromonas spp. were isolated from the feces, skin and rearing environments of pet turtles and identified by biochemical and gyrB sequence analyses. Aeromonas enteropelogenes was the predominant species among the isolates (52.9%) followed by A. hydrophila (32.4%), A. dharkensis (5.9%), A. veronii (4.9%) and A. caviae (3.9%). Their potential enterotoxicities were evaluated by PCR assays for detecting genes encoding cytotoxic enterotoxin (act) and two cytotonic enterotoxins (alt and ast). 75.8% of A. hydrophila isolates exhibited the act + /alt + /ast + genotype, whereas 94.4% of A. enteropelogenes isolates were determined to be act - /alt - /ast - . In an antimicrobial susceptibility test, most isolates were susceptible to all tested antibiotics except amoxicillin, ampicillin, cephalothin, chloramphenicol and tetracycline. Non-susceptible isolates to penicillins (ampicillin and amoxicillin) and fluoroquinolones (ciprofloxacin and norfloxacin) were frequently observed among the A. enteropelogenes isolates. Few isolates were resistant to imipenem, amikacin, ceftriaxone and cefotaxime. Collectively, these results suggest that pet turtles may pose a public health risk of infection by enterotoxigenic and antimicrobial resistant Aeromonas strains.

  12. ANTIMICROBIAL ACTIVITY OF NONTRADITIONAL PLANT POLLEN AGAINST DIFFERENT SPECIES OF MICROORGANISMS

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    Miroslava Kačániová

    2014-08-01

    Full Text Available The aim of this study was to detect the antimicrobial activity of four plant pollen samples to pathogenic bacteria, microscopic fungi and yeasts. Pollens of dogwood common (Cornus mas, ray mountain (Secale strictum spp. strictum, pumpkin rape (Cucurbita pepo var. styriaca and grape vine (Vitis vinifera were collected in 2010 in Slovakia. The antimicrobial effects of the four nontraditional plant pollens were tested using the agar well diffusion method. For extraction, 70% ethanol (aqueous, v/v was applied. Antimicrobial susceptibility of five different strains of bacteria - three gram positive (Listeria monocytogenes CCM 4699, Pseudomonas aeruginosa CCM 1960, Staphylococcus aureus CCM 3953 and gram negative (Salmonella enterica CCM 4420, Escherichia coli CCM 3988, as well as three different strains of microscopic fungi, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and three different strains of yeasts Candida albicans, Geotrichum candidum and Rhodotorula mucilaginosa, were examinated. L. monocytogenes was the most sensitive among bacteria to the three ethanol extracts of plant pollen after 24 hours of inoculation, A. flavus and C. albicans were the most sensitive microscopic fungi and yeast species, respectively.

  13. Species of Genus Ganoderma (Agaricomycetes) Fermentation Broth: A Novel Antioxidant and Antimicrobial Agent.

    Science.gov (United States)

    Cilerdzic, Jasmina; Kosanic, Marijana; Stajić, Mirjana; Vukojevic, Jelena; Ranković, Branislav

    2016-01-01

    The bioactivity of Ganoderma lucidum basidiocarps has been well documented, but there are no data on the medicinal properties of its submerged cultivation broth nor on the other species of the genus Ganoderma. Thus the aim of this study was to test the potential antimicrobial and antioxidant activity of fermentation broth obtained after submerged cultivation of G. applanatum, G. carnosum, and G. lucidum. DPPH· scavenging ability, total phenols, and flavonoid contents were measured to determine the antioxidative potential of Ganoderma spp. fermentation filtrates, whereas their antimicrobial potential was studied using the microdilution method. DPPH· scavenging activity of G. lucidum fermentation filtrates was significantly higher than that of G. applanatum and G. carnosum, with the maximum (39.67%) obtained from strain BEOFB 432. This filtrate also contained the highest concentrations of phenols (134.89 μg gallic acid equivalents/mL) and flavonoids (42.20 μg quercetin equivalent/mL). High correlations between the activity and phenol content in the extracts showed that these compounds were active components of the antioxidative activity. G. lucidum strain BEOFB 432 was the most effective antibacterial agent, whereas strain BEOFB 434 has proven to be the most effective antifungal agent. The study showed that Ganoderma spp. fermentation filtrates are novel potent antioxidative and antimicrobial agents that could be obtained more quickly and cheaper than basidiocarps.

  14. Antimicrobial Potential of Momordica charantia L. against Multiresistant Standard Species and Clinical Isolates.

    Science.gov (United States)

    Lucena Filho, José Hardman Sátiro de; Lima, Rennaly de Freitas; Medeiros, Ana Claudia Dantas de; Pereira, Jozinete Vieira; Granville-Garcia, Ana Flávia; Costa, Edja Maria Melo de Brito

    2015-11-01

    The aim of the present study was to evaluate the antibacterial and antifungal potential in vitro of Momordica charantia L. against the microorganisms of clinical interest (standard strains and multiresistant isolates) in order to aggregate scientific information in relation to its use as a therapeutic product. M. charantia L. plant material was acquired in municipality of Malta, Paraiba, Brazil. The extract was obtained through maceration, filtration and then concentrated under reduced pressure in a rotary evaporator, resulting in a dough, and was then dried in an oven for 72 hours at 40°C. Antimicrobial action of ethanolic extract of seed M. charantia L. was evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) against standard strains of bacteria, isolates multiresistant bacteria and Candida species, by microdilution in broth method. All organisms were sensitive to the extract, being considered strong antimicrobial activity (MIC and MBC/MFC charantia L. showed strong antimicrobial potential, with bactericidal and fungicidal profile, there is the prospect to constitute a new therapeutic strategy for the control of infections, particularly in multiresistant strains. The use of medicinal plants in treatment of infectious processes have an important function nowadays, due to the limitations of the use of synthetic antibiotics available, related specifically to the microbial resistance emergence.

  15. Antimicrobial and antioxidant activities of phenolic compound extracted from new verbascum species growing in Turkey

    International Nuclear Information System (INIS)

    Saltan, F.Z.; Sokmen, M.; Akin, M.; Saracoglu, H.T.; Gokturk, R.S.; Ahmad, M.; Ali, M.; Shah, M.R.

    2011-01-01

    The aim of this study was to evaluate the antimicrobial and antioxidant potential of the aerial parts of four new Verbascum L. (Scrophulariaceae) species namely, Verbascum bellum Hub.-Mor., Verbascum detersile Boiss. and Heldr., Verbascum myriocarpum Boiss. and Heldr. and Verbascum pestalozzae Boiss., growing in Turkey. Plant materials were extracted with chloroform, ethylacetate and methanol for antimicrobial tests. These extracts were assayed against both gram-positive and gram-negative bacteria by the microdilution method. The minimum inhibitory concentrations of the Verbascum species varied between 150-0.59 mg/ml. In general, ethylacetate extract was effective for E. coli (ATCC 25922, 1.88 mg/ml). Ethyl acetate extract of V. pestalozzae exhibited the highest effect on P. aeroginosa (ATCC 29853, 0.59 mg/ml). The antioxidant capacity of the studied species was only tested with methanol extracts. Their antioxidant action was tested by DPPH and beta-carotene-linoleic acid methods. While V. pestalozzae (IC/sub 50/=15 mu g/ml) exhibited the strongest activity in DPPH assay, V. detersile and V. pestalozzae provided an excellent inhibition effect (100% RAA) in the beta-caroten- linoleic acid system. HPLC analysis of methanol extracts was also carried out to determine the composition of the phenolic compounds responsible for the activity. Methanol extracts were also subjected to HPLC analysis to determine their phenolic compound profile. (author)

  16. Antimicrobial activity of the pygidial gland secretion of three ground beetle species (Insecta: Coleoptera: Carabidae)

    Science.gov (United States)

    Nenadić, Marija; Soković, Marina; Glamočlija, Jasmina; Ćirić, Ana; Perić-Mataruga, Vesna; Ilijin, Larisa; Tešević, Vele; Vujisić, Ljubodrag; Todosijević, Marina; Vesović, Nikola; Ćurčić, Srećko

    2016-04-01

    The antimicrobial properties of the pygidial gland secretions released by the adults of the three ground beetle species, Carabus ullrichii, C. coriaceus, and Abax parallelepipedus, have been tested. Microdilution method was applied for detection of minimal inhibitory concentrations (MICs), minimal bactericidal concentrations (MBCs), and minimal fungicidal concentrations (MFCs). Additionally, morpho-histology of the pygidial glands is investigated. We have tested 16 laboratory and clinical strains of human pathogens—eight bacterial both gram-positive and gram-negative species and eight fungal species. The pygidial secretion samples of C. ullrichii have showed the strongest antimicrobial effect against all strains of treated bacteria and fungi. Staphylococcus aureus, Lysteria monocytogenes, and Salmonella typhimurium proved to be the most sensitive bacterial strains. Penicillium funiculosum proved to be the most sensitive micromycete, while P. ochrochloron and P. verrucosum var . cyclopium the most resistant micromycetes. The pygidial secretion of C. coriaceus has showed antibacterial potential solely against Pseudomonas aeruginosa and antifungal activity against Aspergillus fumigatus, A. versicolor, A. ochraceus, and P. ochrochloron. Antibacterial properties of pygidial gland secretion of A. parallelepipedus were achieved against P. aeruginosa, while antifungal activity was detected against five of the eight tested micromycetes (A. fumigatus, A. versicolor, A. ochraceus, Trichoderma viride, and P. verrucosum var . cyclopium). Commercial antibiotics Streptomycin and Ampicillin and mycotics Ketoconazole and Bifonazole, applied as the positive controls, showed higher antibacterial/antifungal properties for all bacterial and fungal strains. The results of this observation might have a significant impact on the environmental aspects and possible medical purpose in the future.

  17. Prevalence and antimicrobial resistance of listeria species isolated from different types of raw meat in Iran.

    Science.gov (United States)

    Rahimi, Ebrahim; Yazdi, Farzad; Farzinezhadizadeh, Hussein

    2012-12-01

    Listeria and particularly Listeria monocytogenes are important foodborne pathogens that can cause listeriosis and severe complications in immunocompromised individuals, children, pregnant women, and the elderly. The objective of this study was to determine the prevalence of Listeria spp. in raw meat in Iran. From July 2010 to November 2011, a total of 1,107 samples of various raw meats were obtained from randomly selected retail butcher shops. The results of conventional bacteriologic and PCR methods revealed that 141 samples (12.7%) were positive for Listeria spp. The highest prevalence of Listeria was found in raw buffalo meat samples (7 of 24 samples; 29.2%) followed by quail meat (26 of 116 samples; 22.4%), partridge meat (13 of 74 samples; 17.6%), and chicken meat (27 of 160 samples; 16.9%). The most common species recovered was Listeria innocua (98 of 141 strains; 75.9 % ); the remaining isolates were L. monocytogenes (19.1% of strains), Listeria welshimeri (6.4% of strains), Listeria seeligeri (3.5% of strains), and Listeria grayi (1.4% of strains). Susceptibilities of the 141 strains to 11 antimicrobial drugs were determined using the disk diffusion assay. Overall, 104 (73.8%) of the Listeria isolates were resistant to one or more antimicrobials, and 17.0% of the isolates were resistant to three or more antimicrobials. The present study provides the first baseline data on the prevalence of Listeria in raw meat derived from sheep, goat, buffalo, quail, partridge, chicken, and ostrich in Iran and the susceptibility of these isolates to antimicrobials.

  18. Susceptibility of different bacterial species isolated from food animals to copper sulphate, zinc chloride and antimicrobial substances used for disinfection

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Hasman, Henrik

    2004-01-01

    that Danish bacterial isolates from livestock so far have not or have only to a limited degree developed resistance to antimicrobial compounds commonly used for disinfection. Acquired copper resistance was only found in enterococci. There were large differences in the intrinsic susceptibility of the different...... of susceptibilities to the different antimicrobial agents. Large variations were observed in the susceptibility of the different bacterial species to the different compounds. Staphylococci were in general very susceptible to all antimicrobial compounds tested. The Salmonella isolates were in general less susceptible...

  19. Current Advances in the Antimicrobial Potential of Species of Genus Ganoderma (Higher Basidiomycetes) against Human Pathogenic Microorganisms (Review).

    Science.gov (United States)

    Rai, Mahendra K; Gaikwad, Swapnil; Nagaonkar, Dipali; dos Santos, Carolina Alves

    2015-01-01

    Ganoderma spp. are very important therapeutic mushrooms and have been used traditionally for 4000 years in the treatment of various human disorders. Different species of Ganoderma possess bioactive compounds, which have already demonstrated antiviral, antibacterial, and antifungal activities. Various bioactive compounds such as triterpenoids, colossolactones, and polysaccharides, which are responsible for the antimicrobial potential of the genus, are discussed here in detail. Some Ganoderma spp. have been reported to be potential agents for the synthesis of metal nanoparticles. These nanoparticles have demonstrated antimicrobial activity and also are reviewed herein. The main aim of this review is to discuss the possible use of Ganoderma extracts and their active principles in antimicrobial therapy.

  20. Molecular and antimicrobial susceptibility profiling of atypical Streptococcus species from porcine clinical specimens.

    Science.gov (United States)

    Moreno, Luisa Z; Matajira, Carlos E C; Gomes, Vasco T M; Silva, Ana Paula S; Mesquita, Renan E; Christ, Ana Paula G; Sato, Maria Inês Z; Moreno, Andrea M

    2016-10-01

    The Streptococcus species present broad phenotypic variation, making identification difficult using only traditional microbiological methods. Even though Streptococcus suis is the most important species for the worldwide swine industry, other Streptococcus species appear to be able to cause disease in swine and could represent a higher underestimated risk for porcine health. The aim of this study was to identify Streptococcus-like isolates by MALDI-TOF MS and 16S rRNA sequencing and further molecular and antibiotic susceptibility characterization of the atypical Streptococcus species capable of causing disease in swine. Fifty presumptive Streptococcus isolates from diseased pigs isolated from different Brazilian States between 2002 and 2014 were evaluated. Among the studied isolates, 26% were identified as Streptococcus hyovaginalis, 24% as Streptococcus plurianimalium, 12% as Streptococcus alactolyticus, 10% as Streptococcus hyointestinalis, and the remaining isolates belonged to Streptococcus henryi (6%), Streptococcus thoraltensis (6%), Streptococcus gallolyticus (6%), Streptococcus gallinaceus (4%), Streptococcus sanguinis (4%), and Streptococcus mitis (2%). The Streptococcus isolates were successfully identified by spectral cluster analysis and 16S rRNA sequencing with 96% of concordance between the techniques. The SE-AFLP analysis also supported Streptococcus species distinction and enabled further observation of higher genetic heterogeneity intra-species. The identified Streptococcus species presented variable MIC values to β-lactams, enrofloxacin and florfenicol, and high resistance rates to tetracyclines and macrolides, which appear to be directly related to the industry's antimicrobial usage and resistance selection. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Reactive oxygen species play no role in the candidacidal activity of the salivary antimicrobial peptide histatin 5

    OpenAIRE

    Veerman, Enno C. I.; Nazmi, Kamran; van '​t HOF, Wim; Bolscher, Jan G. M.; den Hertog, Alice L.; Nieuw Amerongen, Arie V.

    2004-01-01

    The mechanism of action of antimicrobial peptides is still a matter of debate. The formation of ROS (reactive oxygen species) has been suggested to be the crucial step in the fungicidal mechanism of a number of antimicrobial peptides, including histatin 5 and lactoferrin-derived peptides. In the present study we have investigated the effects of histatin 5 and of a more amphipathic synthetic derivative, dhvar4, on the generation of ROS in the yeast Candida albicans, using dihydroethidium as an...

  2. SPECIES DISTRIBUTIONS, SURROGACY, AND IMPORTANT CONSERVATION REGIONS IN CANADA

    Science.gov (United States)

    Conservation actions could be more efficient if there is congruence among taxa in the distribution of species. Patterns in the geographic distribution of species of six taxa were used to identify nationally important sites for conservation in Canada. Species richness and a meas...

  3. Antimicrobial activity and chemical constituents of essential oils and oleoresins extracted from eight pepper species

    Directory of Open Access Journals (Sweden)

    Laira Martinelli

    Full Text Available ABSTRACT: Essential oils are the most important compounds produced during secondary metabolism in aromatic plants. Essential oils are volatile, have characteristic odor and are used as defensive agents by plants. In pepper, it is possible to say that essential oils are the “flavor fingerprint” of each species. In the present article, eight species of pepper were studied in order to extract their essential oils and oleoresins, test their antibacterial and antifungal activities and also to identify the compounds present in the most bioactive samples. Results demonstrated that two essential oils [Pimenta dioica (L. Merr. and Schinus terebinthifolius] and three oleoresins (Schinus terebinthifolius and Piper nigrum white and black recorded significant antimicrobial activity. These active essential oils and oleoresins are interesting for use in biotechnological processes employed in food, pharmaceutical and other industries.

  4. Infusing considerations of trophic dependencies into species distribution modelling.

    Science.gov (United States)

    Trainor, Anne M; Schmitz, Oswald J

    2014-12-01

    Community ecology involves studying the interdependence of species with each other and their environment to predict their geographical distribution and abundance. Modern species distribution analyses characterise species-environment dependency well, but offer only crude approximations of species interdependency. Typically, the dependency between focal species and other species is characterised using other species' point occurrences as spatial covariates to constrain the focal species' predicted range. This implicitly assumes that the strength of interdependency is homogeneous across space, which is not generally supported by analyses of species interactions. This discrepancy has an important bearing on the accuracy of inferences about habitat suitability for species. We introduce a framework that integrates principles from consumer-resource analyses, resource selection theory and species distribution modelling to enhance quantitative prediction of species geographical distributions. We show how to apply the framework using a case study of lynx and snowshoe hare interactions with each other and their environment. The analysis shows how the framework offers a spatially refined understanding of species distribution that is sensitive to nuances in biophysical attributes of the environment that determine the location and strength of species interactions. © 2014 John Wiley & Sons Ltd/CNRS.

  5. In vitro antimicrobial effect of Satureja wiedemanniana against Bacillus species isolated from raw meat samples.

    Science.gov (United States)

    Yucel, Nihal; Aslim, Belma; Ozdoğan, Hakan

    2009-08-01

    In this study a total of 30 raw meat samples obtained from Ankara, Turkey were screened for the presence of Bacillus species. Among the meat samples analyzed, the predominant species isolated was Bacillus circulans; other Bacillus species were identified as Bacillus firmus, Bacillus lentus, Bacillus megaterium, Bacillus licheniformis, Bacillus mycoides, Bacillus sphaericus, and Bacillus cereus. Minced meat samples were more contaminated with Bacillus species than sliced beef sample. From these samples, 242 Bacillus species isolates were obtained, which were investigated for proteolytic and lipolytic activity, associated with meat spoilage. Interestingly, some Bacillus strains produced the highest values of proteolytic/lipolytic activities. Nineteen Bacillus strains were selected among the 242 isolates according to their proteolytic/lipolytic activity with a clear zone diameter of > or =6 mm. The essential oil of Satureja wiedemanniana (Lalem) Velen was also tested against these 19 Bacillus species that had proteolytic and lipolytic activity. The essential oil yield obtained from the aerial parts of the plant was 0.35% (vol/wt). The inhibition zones of the essential oil obtained against all the Bacillus species were in the range of 5.0-12.0 mm. The oil showed high antimicrobial activities against B. licheniformis M 6(26), M 11(16), and M 12(1) strains. B. licheniformis 12(1) showed high lipolytic activity (18.0 mm). Also, B. licheniformis M 6(26) and M 11(16) showed high proteolytic activity (16.0 and 14.0 mm). These results may suggest that an essential oil of S. wiedemanniana can be used as a natural preservative in meat against spoilage bacteria.

  6. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia; Estrada, Alba; Font, Xavier; Matias, Miguel G.; Meireles, Catarina; Mendoza, Manuel; Honrado, Joao P.; Prasad, Hari D.; Vicente, Joana R.; Early, Regan

    2018-01-01

    spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. 'community structure') reflects assembly processes occurring at small scales

  7. Altered distribution of technetium-99m sodium pertechnetate associated with antimicrobial therapy

    International Nuclear Information System (INIS)

    Castronuovo, J.J.; Chervu, L.R.; Milstein, D.M.

    1985-01-01

    Three patients underwent brain scanning for evaluation of central nervous system disease and were simultaneously treated for infectious diseases unrelated to the central nervous process. All revealed intense vascular pooling on their brain images. The imaging studies had been performed following the administration of Tc-99m pertechnetate. None of the patients had prior nuclear medicine examinations to suggest the causal effect of stannous ion as a source of interference. All of the patients were on combination antimicrobial drugs: two on sulfamethoxazole and trimethoprim, and one on isoniazid and ethambutol. One patient revealed 75% Tc-99m red cell tagging. Another patient's repeat brain scan with Tc-99m DTPA revealed normal distribution. Our findings suggest that patients on antimicrobial combination drug regimens who require brain scans should be imaged routinely with agents other than Tc-99m

  8. Equilibrium of global amphibian species distributions with climate

    DEFF Research Database (Denmark)

    Munguí­a, Mariana; Rahbek, Carsten; Rangel, Thiago F.

    2012-01-01

    A common assumption in bioclimatic envelope modeling is that species distributions are in equilibrium with contemporary climate. A number of studies have measured departures from equilibrium in species distributions in particular regions, but such investigations were never carried out for a compl...

  9. Big data of tree species distributions

    DEFF Research Database (Denmark)

    Serra-Diaz, Josep M.; Enquist, Brian J.; Maitner, Brian

    2018-01-01

    are currently available in big databases, several challenges hamper their use, notably geolocation problems and taxonomic uncertainty. Further, we lack a complete picture of the data coverage and quality assessment for open/public databases of tree occurrences. Methods: We combined data from five major...... and data aggregation, especially from national forest inventory programs, to improve the current publicly available data.......Background: Trees play crucial roles in the biosphere and societies worldwide, with a total of 60,065 tree species currently identified. Increasingly, a large amount of data on tree species occurrences is being generated worldwide: from inventories to pressed plants. While many of these data...

  10. species composition, relative abundance and distribution

    African Journals Online (AJOL)

    Preferred Customer

    College of Natural Sciences, Addis Ababa University, 2011. ISSN: 0379– ... distribution at Entoto Natural Park and escarpment was carried out during July 2009 - March 2010. The study ..... University Press, Princeton and Oxford, 496 pp. 20.

  11. Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

    Science.gov (United States)

    Keeley, Jon E.

    2003-01-01

    Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2. Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution.

  12. Evaluation of fruit extracts of six Turkish Juniperus species for their antioxidant, anticholinesterase and antimicrobial activities.

    Science.gov (United States)

    Oztürk, Mehmet; Tümen, İbrahim; Uğur, Aysel; Aydoğmuş-Öztürk, Fatma; Topçu, Gülaçtı

    2011-03-30

    Juniperus L. (Cupressaceae) species are mostly spread out in the Northern Hemisphere of the world, and some of them are used as folkloric medicines. The fruits of some species are eaten. Since oxidative stress is one of the reasons for neurodegeneration and is associated with the Alzheimer's disease (AD), the extracts prepared from the fruits of six Juniperus species were screened for their antioxidant activity. Therefore, the extracts were also evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), which are chief enzymes in the pathogenesis of AD. In addition, antimicrobial activity was also evaluated. In the β-carotene-linoleic acid assay, acetone extracts of J. oxycedrus subsp. oxycedrus, J. sabina and J. excelsa, and methanol extracts of J. phoenicea and J. sabina, effectively inhibited oxidation of linoleic acid. The hexane extracts of J. oxycedrus subsp. oxycedrus, J. foetidissima and J. phoenicea showed remarkable inhibitory effect against AChE and BChE. Because of their high antioxidant activity, J. excelsa, J. oxycedrus subsp. oxycedrus, J. sabina and J. phoenicia might be used in the food industry as preservative agents or extension of the shelf-life of raw and processed foods. Since the hexane extracts of J. oxycedrus subsp. oxycedrus and J. foetidissima demonstrated significant anticholinesterase activity they should be considered as a potential source for anticholinesterase agents. Copyright © 2010 Society of Chemical Industry.

  13. Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

    Science.gov (United States)

    Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H

    1991-02-01

    The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar.

  14. Antimicrobial susceptibility of coagulase-negative Staphylococcus species isolated from bovine milk.

    Science.gov (United States)

    Sawant, A A; Gillespie, B E; Oliver, S P

    2009-02-16

    Coagulase-negative Staphylococcus (CNS) isolates (n=168) obtained from milk from heifers and dairy cows were screened for minimum inhibitory concentration (MIC) to antimicrobials used commonly for mastitis therapy. Of the 10 CNS species included in the study, the predominant species were Staphylococcus chromogenes (n=61), Staphylococcus epidermidis (n=37), Staphylococcus hyicus (n=37), and Staphylococcus simulans (n=16). The majority of CNS was susceptible to ampicillin, oxacillin, cephalothin, and ceftiofur. Erythromycin and pirlimycin were also very effective in vitro inhibitors of CNS. The only exception was observed with S. epidermidis. Of 37 S. epidermidis evaluated, 13 (35%) exhibited efflux-based resistance to erythromycin (> or =16 microg/ml) encoded by msrA and one isolate carried ermC encoding ribosomal methylase-based resistance to both erythromycin (> or =64 microg/ml) and pirlimycin (> or =64 microg/ml). A total of 17 S. epidermidis, 11 S. chromogenes, and one S. hyicus exhibited phenotypic resistance to ampicillin (> or =0.5 microg/ml). Constitutive beta-lactamase production was observed in all ampicillin resistant isolates except 4 S. epidermidis that exhibited inducible beta-lactamase production. Induced beta-lactamase production was also observed in 13 S. epidermidis that were phenotypically susceptible to the entire MIC panel. All isolates that produced beta-lactamase either constitutively or by induction carried blaZ. S. epidermidis (n=12, 32%) that were resistant to methicillin (oxacillin > or =0.5 microg/ml) carried low affinity penicillin-binding protein encoded by mecA. Most multi-drug resistant (MDR) S. epidermidis (> or =2 resistance genes) were resistant to ampicillin, erythromycin and methicillin. All except one MDR S. epidermidis had icaAB, which encodes for polysaccharide intercellular adhesion. Based on pulsed field gel electrophoresis, MDR S. epidermidis were closely related genotypically, and were isolated from different cows on the

  15. Weather, not climate, defines distributions of vagile bird species.

    Directory of Open Access Journals (Sweden)

    April E Reside

    Full Text Available BACKGROUND: Accurate predictions of species distributions are essential for climate change impact assessments. However the standard practice of using long-term climate averages to train species distribution models might mute important temporal patterns of species distribution. The benefit of using temporally explicit weather and distribution data has not been assessed. We hypothesized that short-term weather associated with the time a species was recorded should be superior to long-term climate measures for predicting distributions of mobile species. METHODOLOGY: We tested our hypothesis by generating distribution models for 157 bird species found in Australian tropical savannas (ATS using modelling algorithm Maxent. The variable weather of the ATS supports a bird assemblage with variable movement patterns and a high incidence of nomadism. We developed "weather" models by relating climatic variables (mean temperature, rainfall, rainfall seasonality and temperature seasonality from the three month, six month and one year period preceding each bird record over a 58 year period (1950-2008. These weather models were compared against models built using long-term (30 year averages of the same climatic variables. CONCLUSIONS: Weather models consistently achieved higher model scores than climate models, particularly for wide-ranging, nomadic and desert species. Climate models predicted larger range areas for species, whereas weather models quantified fluctuations in habitat suitability across months, seasons and years. Models based on long-term climate averages over-estimate availability of suitable habitat and species' climatic tolerances, masking species potential vulnerability to climate change. Our results demonstrate that dynamic approaches to distribution modelling, such as incorporating organism-appropriate temporal scales, improves understanding of species distributions.

  16. Species identification, distribution and abundance of Gerreidae ...

    African Journals Online (AJOL)

    the distribution and abundance of Gerres in estuaries wa'S collected from July 1978 to ..... the channel area between the W.L.R. and the mouth (not the tidal basin) during ..... overwhelming importance in the kelp beds of Britain. Recently Blaber ...

  17. A 9-year study of shigellosis in Northeast Malaysia: Antimicrobial susceptibility and shifting species dominance.

    Science.gov (United States)

    Banga Singh, Kirnpal-Kaur; Ojha, Suvash Chandra; Deris, Zakuan Zainy; Rahman, Rosliza Abdul

    2011-06-01

    AIMS: In Malaysia, Shigella spp. is the third most common bacterial agent responsible for childhood diarrhoea. This study was conducted to determine the prevalence and antimicrobial susceptibility patterns of Shigella spp. isolated from patients admitted to the Hospital Universiti Sains Malaysia from January 2001 to December 2009. SUBJECTS AND METHODS: A hospital-based retrospective study was used. Stool samples from patients were cultured using a standard culture method. Shigella spp. isolates were identified by biochemical and serological methods, and the antimicrobial susceptibility pattern was evaluated using the Kirby-Bauer disc-diffusion method. RESULTS: A total of 138 Shigella spp. were isolated from a total of 14,830 routine stool specimens, yielding an isolation rate of 0.93% that corresponded to 9.99% of the 1,381 bacterial pathogens isolated. Of these isolates, S. sonnei was the predominant species, followed by S. flexneri and S. boydii. Seasonal variation was noticed, and no significant differences were detected in the demographic data for S. flexneri and S. sonnei. The susceptibility of all isolated Shigella strains was tested against seven antibiotics. Ceftriaxone (99.1%), ciprofloxacin (98.4%), and nalidixic acid (93.8%) were effective against the Shigella strains, whereas tetracycline and trimethoprim-sulfamethoxazole exhibited high frequencies of resistance (58.4% and 53.8%, respectively). CONCLUSION: This study is important for public health education aimed at reducing the morbidity and mortality associated with Shigella spp. infection. Our results also will be helpful for paediatricians and microbiologists in the selection of appropriate antibiotics for the management of diarrhoea.

  18. A simple model for skewed species-lifetime distributions

    KAUST Repository

    Murase, Yohsuke

    2010-06-11

    A simple model of a biological community assembly is studied. Communities are assembled by successive migrations and extinctions of species. In the model, species are interacting with each other. The intensity of the interaction between each pair of species is denoted by an interaction coefficient. At each time step, a new species is introduced to the system with randomly assigned interaction coefficients. If the sum of the coefficients, which we call the fitness of a species, is negative, the species goes extinct. The species-lifetime distribution is found to be well characterized by a stretched exponential function with an exponent close to 1/2. This profile agrees not only with more realistic population dynamics models but also with fossil records. We also find that an age-independent and inversely diversity-dependent mortality, which is confirmed in the simulation, is a key mechanism accounting for the distribution. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

  19. Antimicrobial susceptibility pattern of acinetobacter species-one year experience in a tertiary care setting

    International Nuclear Information System (INIS)

    Qureshi, Z.A.; Abbasi, S.A.; Mirza, I.A.; Malik, N.; Sattar, A.

    2012-01-01

    Objective: To find out antimicrobial susceptibility pattern of Acinetobacter species isolated from 1 January 2009 through 31 December 2009 at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi. Materials and Methods: A total of 276 isolates of Acinetobacter spp yielded from various clinical specimens during the study period were included Routine conventional methods were used to identify various species of Acinetobacter and modified Kirby-Bauer disk diffusion method was used for susceptibility testing. Out of total 276 isolates, 176 (63.8%) turned out to be Acinetobacter baumannii and 100 (36.2%) were Acinetobacter johnsonii. Overall sensitivity of Acinetobacter spp against piperacillin/sulbactam, tigecycline, sulbactam/cefoperazone, piperacillin/tazobactam, imipenem, doxycycline, ceftazidime, ciprofloxacin, chloramphenicol, trimethoprim /sulfamethoxazole, ampicillin, gentamycin, ceftriaxone, amoxicillin/clavulanic acid and ampicillin were 64%,63%, 48%, 47%, 41%,39%,35%, 34%, 32%, 31 %, 29%, 19%, 18% and 5% respectively. Out of 276 isolates, 181 (66 %) were multidrug resistant while 33 (18 %) isolates were pan-drug resistant. (author)

  20. Chemosystematic Value of the Essential Oil Composition of Thuja species Cultivated in Poland—Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Caroline Spyropoulos

    2009-11-01

    Full Text Available In the framework of the correlation between chemotaxonomy and chemical analysis studies, the chemical composition of the essential oils of four varieties of Thuja species cultivated in Poland − T. occidentalis ‘globosa’, T. occidentalis ‘aurea’, T. plicata and T. plicata ‘gracialis’ − were investigated by GC and GC-MS. Thirty-one compounds were identified from T. occidentalis ‘globosa’, representing 96.92% of the total oil; twenty-seven from T. occidentalis ‘aurea’ (94.34%; thirty-one from T. plicata (94.75%; and thirty compounds from T. plicata ‘gracialis’ (96.36%. The main constituents in all samples were the monoterpene ketones α- and β-thujone, fenchone and sabinene, as well as the diterpenes beyerene and rimuene.The chemosystematic value of the total ketone content of all samples (which varied from 54.30–69.18% has been discussed and investigated. The constituents, beyerene and the mixture of α- and β-thujone, were isolated from the oils and tested against six Gram-positive and -negative bacteria and three pathogenic fungi. The oils of the two T. plicata species exhibited significant antimicrobial activity, while the mixture of α- and β-thujone showed very strong activity as well.

  1. Antimicrobial susceptibility pattern in nosocomial infections caused by Acinetobacter species in Asir Region, Saudi Arabia.

    Science.gov (United States)

    Abdalla, Nazar M; Osman, Amani A; Haimour, Waleed O; Sarhan, Mohammed A A; Mohammed, Mohammed N; Zyad, Eyhab M; Al-Ghtani, Abdalla M

    2013-03-15

    This study aimed at evaluating the sensitivity of antibiotics towards nosocomial infections caused by Acinetobacter species. The study took place during the period Dec. 2011- Dec. 2012 at Assir Central Hospital in collaboration with the department of microbiology, college of medicine, King Khalid University, Abha. A prospective study involving 150 patients presented with nosocomial infections due to Acinetobacter species detected by bacteriological tests; direct microscopy, culture in blood agar media, fermentation test in MacConkey media and MIC (minimum inhibitory concentration) for antibiotics sensitivity using Muller Hinton media and Chemical test using API 20. A 150 nosocomial infections in this study showed gram-negative coccobacilli, non motile, glucose-negative fermentor and oxidase negative. All isolates showed 100% sensitivity to: Imipramine, Meropenem, Colistin. From the rest of tested antibiotics the higher resistant ones were; Nitrofurantoin 87% and Cefoxitin 85%. The least resistant antibiotics; Imipenem 3% and Ticarcillin 7%. While variable resistance in the rest of tested antimicrobials. A 47 patients (31.3%) have used antibiotics prior to this study. The high rate of usage occurred in elder patients. The frequency of Acinetobacter calcoaceticus baumannii complex multi-drugs resistance ABCMDR is rising including almost all commonly used antibiotics. Only few antibiotics exert 100% sensitivity towards these bacteria.

  2. Prevalence and antimicrobial susceptibility of Ureaplasma species and Mycoplasma hominis in Greek female outpatients, 2012-2016.

    Science.gov (United States)

    Maraki, Sofia; Mavromanolaki, Viktoria Eirini; Nioti, Eleni; Stafylaki, Dimitra; Minadakis, George

    2017-11-28

    Mycoplasma hominis and Ureaplasma species are opportunistic pathogens associated with urogenital infections, complications during pregnancy and postpartum infections. Appropriate empirical antimicrobial treatment is necessary to achieve an optimal therapeutic outcome. This study evaluated the prevalence and the antimicrobial susceptibility of Mycoplasma hominis and Ureaplasma spp. isolated from 1,008 endocervical samples of outpatients in Crete, Greece, during a five-year period (2012-2016), using the commercially available Mycoview kit (Zeakon diagnostics, France). Ureaplasma spp. was isolated from 116 patients (11.5%), M. hominis from 6 (0.6%), while coinfection with both mycoplasmas was demonstrated in 17 (1.7%). All Ureaplasma strains were susceptible to josamycin and doxycycline. Doxycycline, minocycline and ofloxacin were the most potent antibiotics against M. hominis. Docycycline was proved the most active and is still the drug of choice for the treatment of genital mycoplasma infections. Local surveillance to monitor changes in antimicrobial susceptibilities is necessary to guide treatment strategies.

  3. Book review: A new view on the species abundance distribution

    Science.gov (United States)

    DeAngelis, Donald L.

    2018-01-01

    The sampled relative abundances of species of a taxonomic group, whether birds, trees, or moths, in a natural community at a particular place vary in a way that suggests a consistent underlying pattern, referred to as the species abundance distribution (SAD). Preston [1] conjectured that the numbers of species, plotted as a histogram of logarithmic abundance classes called octaves, seemed to fit a lognormal distribution; that is, the histograms look like normal distributions, although truncated on the left-hand, or low-species-abundance, end. Although other specific curves for the SAD have been proposed in the literature, Preston’s lognormal distribution is widely cited in textbooks and has stimulated attempts at explanation. An important aspect of Preston’s lognormal distribution is the ‘veil line’, a vertical line drawn exactly at the point of the left-hand truncation in the distribution, to the left of which would be species missing from the sample. Dewdney rejects the lognormal conjecture. Instead, starting with the long-recognized fact that the number of species sampled from a community, when plotted as histograms against population abundance, resembles an inverted J, he presents a mathematical description of an alternative that he calls the ‘J distribution’, a hyperbolic density function truncated at both ends. When multiplied by species richness, R, it becomes the SAD of the sample.

  4. The role of biotic interactions in shaping distributions and realised assemblages of species: implications for species distribution modelling.

    Science.gov (United States)

    Wisz, Mary Susanne; Pottier, Julien; Kissling, W Daniel; Pellissier, Loïc; Lenoir, Jonathan; Damgaard, Christian F; Dormann, Carsten F; Forchhammer, Mads C; Grytnes, John-Arvid; Guisan, Antoine; Heikkinen, Risto K; Høye, Toke T; Kühn, Ingolf; Luoto, Miska; Maiorano, Luigi; Nilsson, Marie-Charlotte; Normand, Signe; Öckinger, Erik; Schmidt, Niels M; Termansen, Mette; Timmermann, Allan; Wardle, David A; Aastrup, Peter; Svenning, Jens-Christian

    2013-02-01

    Predicting which species will occur together in the future, and where, remains one of the greatest challenges in ecology, and requires a sound understanding of how the abiotic and biotic environments interact with dispersal processes and history across scales. Biotic interactions and their dynamics influence species' relationships to climate, and this also has important implications for predicting future distributions of species. It is already well accepted that biotic interactions shape species' spatial distributions at local spatial extents, but the role of these interactions beyond local extents (e.g. 10 km(2) to global extents) are usually dismissed as unimportant. In this review we consolidate evidence for how biotic interactions shape species distributions beyond local extents and review methods for integrating biotic interactions into species distribution modelling tools. Drawing upon evidence from contemporary and palaeoecological studies of individual species ranges, functional groups, and species richness patterns, we show that biotic interactions have clearly left their mark on species distributions and realised assemblages of species across all spatial extents. We demonstrate this with examples from within and across trophic groups. A range of species distribution modelling tools is available to quantify species environmental relationships and predict species occurrence, such as: (i) integrating pairwise dependencies, (ii) using integrative predictors, and (iii) hybridising species distribution models (SDMs) with dynamic models. These methods have typically only been applied to interacting pairs of species at a single time, require a priori ecological knowledge about which species interact, and due to data paucity must assume that biotic interactions are constant in space and time. To better inform the future development of these models across spatial scales, we call for accelerated collection of spatially and temporally explicit species data. Ideally

  5. Near term climate projections for invasive species distributions

    Science.gov (United States)

    Jarnevich, C.S.; Stohlgren, T.J.

    2009-01-01

    Climate change and invasive species pose important conservation issues separately, and should be examined together. We used existing long term climate datasets for the US to project potential climate change into the future at a finer spatial and temporal resolution than the climate change scenarios generally available. These fine scale projections, along with new species distribution modeling techniques to forecast the potential extent of invasive species, can provide useful information to aide conservation and invasive species management efforts. We created habitat suitability maps for Pueraria montana (kudzu) under current climatic conditions and potential average conditions up to 30 years in the future. We examined how the potential distribution of this species will be affected by changing climate, and the management implications associated with these changes. Our models indicated that P. montana may increase its distribution particularly in the Northeast with climate change and may decrease in other areas. ?? 2008 Springer Science+Business Media B.V.

  6. Characterization of Quercus species distributed in Jordan using ...

    African Journals Online (AJOL)

    Characterization of Quercus species distributed in Jordan using morphological and molecular markers. Mohammad S Jawarneh, Mohammad H Brake, Riyadh Muhaidat, Hussein M Migdadi, Jamil N Lahham, Ahmad Ali El-Oqlah ...

  7. Mistaking geography for biology: inferring processes from species distributions.

    Science.gov (United States)

    Warren, Dan L; Cardillo, Marcel; Rosauer, Dan F; Bolnick, Daniel I

    2014-10-01

    Over the past few decades, there has been a rapid proliferation of statistical methods that infer evolutionary and ecological processes from data on species distributions. These methods have led to considerable new insights, but they often fail to account for the effects of historical biogeography on present-day species distributions. Because the geography of speciation can lead to patterns of spatial and temporal autocorrelation in the distributions of species within a clade, this can result in misleading inferences about the importance of deterministic processes in generating spatial patterns of biodiversity. In this opinion article, we discuss ways in which patterns of species distributions driven by historical biogeography are often interpreted as evidence of particular evolutionary or ecological processes. We focus on three areas that are especially prone to such misinterpretations: community phylogenetics, environmental niche modelling, and analyses of beta diversity (compositional turnover of biodiversity). Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  8. Abundance, distribution and species composition of fish larvae in ...

    African Journals Online (AJOL)

    improving our knowledge of the abundance, distribution and species diversity ... banks as well as in the mid-channel, thus eliminating any bias that might have .... cond method (Table 2) may bias the importance of a single species due to one, ...

  9. Identity and distribution of southern African sciaenid fish species of ...

    African Journals Online (AJOL)

    Two Umbrina species, U. canariensis Valenciennes 1843 and U. robinsoni Gilchrist and Thompson 1908, are recognised from southern Africa. The latter species was hitherto believed to be a synonym of Umbrina ronchus Valenciennes 1843 (type locality Canary Islands). U. canariensis is distributed along the South Africa ...

  10. Distribution characteristics of mineral elements in tree Species from ...

    African Journals Online (AJOL)

    Tree species populations were 44 in Akyaakrom (AS), 29 in Dopiri (DS), and families were 18 in AS and 16 in DS. Tree densities were 121 and 99 in AS and DS, respectively, in 0.57 ha. In terms of tree species population, diversity and density, AS was superior to DS. The distribution of major mineral elements in the leaves ...

  11. Dispersal ability determines the scaling properties of species abundance distributions

    DEFF Research Database (Denmark)

    Borda-De-Água, Luís; Whittaker, Robert James; Cardoso, Pedro

    2017-01-01

    with computer simulations, low dispersal ability species generate a hump for intermediate abundance classes earlier than the distributions of high dispersal ability species. Importantly, when plotted as function of sample size, the raw moments of the SADs of arthropods have a power law pattern similar...

  12. The implicit assumption of symmetry and the species abundance distribution

    NARCIS (Netherlands)

    Alonso, D.; Ostling, A.; Etienne, R.S.

    2008-01-01

    Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to

  13. The implicit assumption of symmetry and the species abundance distribution

    NARCIS (Netherlands)

    Alonso, David; Ostling, Annette; Etienne, Rampal S.

    Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to

  14. A globally-distributed alien invasive species poses risks to United States imperiled species.

    Science.gov (United States)

    McClure, Meredith L; Burdett, Christopher L; Farnsworth, Matthew L; Sweeney, Steven J; Miller, Ryan S

    2018-03-28

    In the midst of Earth's sixth mass extinction event, non-native species are a driving factor in many imperiled species' declines. One of the most widespread and destructive alien invasive species in the world, wild pigs (Sus scrofa) threaten native species through predation, habitat destruction, competition, and disease transmission. We show that wild pigs co-occur with up to 87.2% of imperiled species in the contiguous U.S. identified as susceptible to their direct impacts, and we project increases in both the number of species at risk and the geographic extent of risks by 2025. Wild pigs may therefore present a severe threat to U.S. imperiled species, with serious implications for management of at-risk species throughout wild pigs' global distribution. We offer guidance for efficient allocation of research effort and conservation resources across species and regions using a simple approach that can be applied to wild pigs and other alien invasive species globally.

  15. Species Composition, Relative Abundance and Distribution of the ...

    African Journals Online (AJOL)

    Species Composition, Relative Abundance and Distribution of the Avian Fauna of Entoto Natural Park and Escarpment, Addis Ababa. ... Eucalyptus plantation, soil erosion, deforestation, habitat fragmentation, settlement and land degradation were the main threats for the distribution of birds in the present study area.

  16. Sample sizes and model comparison metrics for species distribution models

    Science.gov (United States)

    B.B. Hanberry; H.S. He; D.C. Dey

    2012-01-01

    Species distribution models use small samples to produce continuous distribution maps. The question of how small a sample can be to produce an accurate model generally has been answered based on comparisons to maximum sample sizes of 200 observations or fewer. In addition, model comparisons often are made with the kappa statistic, which has become controversial....

  17. The origin and distribution of neotropical species of Campylopus

    OpenAIRE

    Frahm, Jan-Peter

    1990-01-01

    Of the 65 species of Campylopus known from tropical America, 33 are andine in distribution, 16 are found only in SE Brazil, 8 have wide ranges through Central and South America, 3 species are disjunct in SE-North America and Brazil, 3 are confined to the Caribbean and one species belongs to the circum-pacific and one to the tethyan element. For different parts of the Neotropics, the composition of phytogeographical elements is calculated. For the first time, bryophyte distributions are compar...

  18. Brevibacillus laterosporus, a Pathogen of Invertebrates and a Broad-Spectrum Antimicrobial Species

    Directory of Open Access Journals (Sweden)

    Luca Ruiu

    2013-09-01

    Full Text Available Brevibacillus laterosporus, a bacterium characterized by the production of a unique canoe-shaped lamellar body attached to one side of the spore, is a natural inhabitant of water, soil and insects. Its biopesticidal potential has been reported against insects in different orders including Coleoptera, Lepidoptera, Diptera and against nematodes and mollusks. In addition to its pathogenicity against invertebrates, different B. laterosporus strains show a broad-spectrum antimicrobial activity including activity against phytopathogenic bacteria and fungi. A wide variety of molecules, including proteins and antibiotics, have been associated with the observed pathogenicity and mode of action. Before being considered as a biological control agent against plant pathogens, the antifungal and antibacterial properties of certain B. laterosporus strains have found medical interest, associated with the production of antibiotics with therapeutic effects. The recent whole genome sequencing of this species revealed its potential to produce polyketides, nonribosomal peptides, and toxins. Another field of growing interest is the use of this bacterium for bioremediation of contaminated sites by exploiting its biodegradation properties. The aim of the present review is to gather and discuss all recent findings on this emerging entomopathogen, giving a wider picture of its complex and broad-spectrum biocontrol activity.

  19. Map of Life - A Dashboard for Monitoring Planetary Species Distributions

    Science.gov (United States)

    Jetz, W.

    2016-12-01

    Geographic information about biodiversity is vital for understanding the many services nature provides and their potential changes, yet remains unreliable and often insufficient. By integrating a wide range of knowledge about species distributions and their dynamics over time, Map of Life supports global biodiversity education, monitoring, research and decision-making. Built on a scalable web platform geared for large biodiversity and environmental data, Map of Life endeavors provides species range information globally and species lists for any area. With data and technology provided by NASA and Google Earth Engine, tools under development use remote sensing-based environmental layers to enable on-the-fly predictions of species distributions, range changes, and early warning signals for threatened species. The ultimate vision is a globally connected, collaborative knowledge- and tool-base for regional and local biodiversity decision-making, education, monitoring, and projection. For currently available tools, more information and to follow progress, go to MOL.org.

  20. Uncertainty of future projections of species distributions in mountainous regions.

    Directory of Open Access Journals (Sweden)

    Ying Tang

    Full Text Available Multiple factors introduce uncertainty into projections of species distributions under climate change. The uncertainty introduced by the choice of baseline climate information used to calibrate a species distribution model and to downscale global climate model (GCM simulations to a finer spatial resolution is a particular concern for mountainous regions, as the spatial resolution of climate observing networks is often insufficient to detect the steep climatic gradients in these areas. Using the maximum entropy (MaxEnt modeling framework together with occurrence data on 21 understory bamboo species distributed across the mountainous geographic range of the Giant Panda, we examined the differences in projected species distributions obtained from two contrasting sources of baseline climate information, one derived from spatial interpolation of coarse-scale station observations and the other derived from fine-spatial resolution satellite measurements. For each bamboo species, the MaxEnt model was calibrated separately for the two datasets and applied to 17 GCM simulations downscaled using the delta method. Greater differences in the projected spatial distributions of the bamboo species were observed for the models calibrated using the different baseline datasets than between the different downscaled GCM simulations for the same calibration. In terms of the projected future climatically-suitable area by species, quantification using a multi-factor analysis of variance suggested that the sum of the variance explained by the baseline climate dataset used for model calibration and the interaction between the baseline climate data and the GCM simulation via downscaling accounted for, on average, 40% of the total variation among the future projections. Our analyses illustrate that the combined use of gridded datasets developed from station observations and satellite measurements can help estimate the uncertainty introduced by the choice of baseline

  1. Distribution and diversity of twelve Curcuma species in China.

    Science.gov (United States)

    Zhang, Lanyue; Wei, Jingwen; Yang, Zhiwen; Chen, Feng; Xian, Qiqiu; Su, Ping; Pan, Wanyi; Zhang, Kun; Zheng, Xi; Du, Zhiyun

    2018-02-01

    Genus Curcuma a wild species presents an important source of valuable characters for improving the cultivated Curcuma varieties. Based on the collected germplasms, herbariums, field surveys and other literatures, the ecogeographical diversity of Genus Curcuma and its potential distributions under the present and future climate are analysed by DIVA-GIS. The results indicate Genus Curcuma is distributed over 17 provinces in China, and particularly abundant in Guangxi and Guangdong provinces. The simulated current distributions are close to the actual distribution regions. In the future climate, the suitable areas for four Curcuma species will be extended, while for other three species the regions will be significantly decreased, and thus these valuable resources need protecting.

  2. Integrating human and environmental health in antibiotic risk assessment: A critical analysis of protection goals, species sensitivity and antimicrobial resistance.

    Science.gov (United States)

    Le Page, Gareth; Gunnarsson, Lina; Snape, Jason; Tyler, Charles R

    2017-12-01

    Antibiotics are vital in the treatment of bacterial infectious diseases but when released into the environment they may impact non-target organisms that perform vital ecosystem services and enhance antimicrobial resistance development with significant consequences for human health. We evaluate whether the current environmental risk assessment regulatory guidance is protective of antibiotic impacts on the environment, protective of antimicrobial resistance, and propose science-based protection goals for antibiotic manufacturing discharges. A review and meta-analysis was conducted of aquatic ecotoxicity data for antibiotics and for minimum selective concentration data derived from clinically relevant bacteria. Relative species sensitivity was investigated applying general linear models, and predicted no effect concentrations were generated for toxicity to aquatic organisms and compared with predicted no effect concentrations for resistance development. Prokaryotes were most sensitive to antibiotics but the range of sensitivities spanned up to several orders of magnitude. We show reliance on one species of (cyano)bacteria and the 'activated sludge respiration inhibition test' is not sufficient to set protection levels for the environment. Individually, neither traditional aquatic predicted no effect concentrations nor predicted no effect concentrations suggested to safeguard for antimicrobial resistance, protect against environmental or human health effects (via antimicrobial resistance development). Including data from clinically relevant bacteria and also more species of environmentally relevant bacteria in the regulatory framework would help in defining safe discharge concentrations for antibiotics for patient use and manufacturing that would protect environmental and human health. It would also support ending unnecessary testing on metazoan species. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Chemical analysis of reactive species and antimicrobial activity of/nwater treated by nanosecond pulsed DBD air plasma

    Czech Academy of Sciences Publication Activity Database

    Laurita, R.; Barbieri, D.; Gherardi, M.; Colombo, V.; Lukeš, Petr

    2015-01-01

    Roč. 3, č. 2 (2015), s. 53-61 ISSN 2212-8166 R&D Projects: GA MŠk(CZ) LD14080 Grant - others:European Cooperation in Science and Technology(XE) COST TD1208 Institutional support: RVO:61389021 Keywords : Dielectric barrier discharge * Plasma activated water * Reactive species * Peroxynitrite * Phenol degradation * Candida albicans * Staphylococcus aureus * Antimicrobial activity * Nosocomial infections Subject RIV: BL - Plasma and Gas Discharge Physics http://www.sciencedirect.com/science/article/pii/S2212816615300081

  4. Distribution of virulence determinants among antimicrobial-resistant and antimicrobial-susceptible Escherichia coli implicated in urinary tract infections.

    Science.gov (United States)

    Stephenson, Sam; Brown, P D

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) rely on the correlation of virulence expression with antimicrobial resistance to persist and cause severe urinary tract infections (UTIs). We assessed the virulence pattern and prevalence among UPEC strains susceptible and resistant to multiple antimicrobial classes. A total of 174 non-duplicate UPEC strains from patients with clinically significant UTIs were analysed for susceptibility to aminoglycoside, antifolate, cephalosporin, nitrofuran and quinolone antibiotics for the production of extended-spectrum β-lactamases and for the presence of six virulence determinants encoding adhesins (afimbrial, Type 1 fimbriae, P and S-fimbriae) and toxins (cytotoxic necrotising factor and haemolysin). Relatively high resistance rates to nalidixic acid, ciprofloxacin, cephalothin and trimethoprim-sulfamethoxazole (82%, 78%, 62% and 59%, respectively) were observed. Fourteen distinct patterns were identified for the virulence determinants such as afaBC, cnfI, fimH, hylA, papEF and sfaDE. The toxin gene, cnfI (75.3%), was the second most prevalent marker to the adhesin, fimH (97.1%). The significant association of sfaDE/hylA (P < 0.01) among antimicrobial resistant and susceptible strains was also observed notwithstanding an overall greater occurrence of virulence factors among the latter. This study provides a snapshot of UPEC complexity in Jamaica and highlights the significant clonal heterogeneity among strains. Such outcomes emphasise the need for evidence-based strategies in the effective management and control of UTIs.

  5. Antimicrobial Effect of 15 Medicinal Plant Species and their Dependency on Climatic Conditions of Growth in Different Geographical and Ecological Areas of Fars Province

    Directory of Open Access Journals (Sweden)

    Abbas Abdollahi

    2012-05-01

    Full Text Available Background: The effects of medicinal plants are variable in different conditions. Here, the antimicrobial effect of 15 medicinal plant species and their dependency on the climatic condition of growth in different geographical and ecological areas of Fars Province were studied. Materials and Methods: In This empirical study, the antimicrobial effect of hydro-alcoholic extract of 15 medicinal plant species was examined against standard bacterial strains comparing to conventional therapeutic antibiotics using disk diffusion assay and serial broth dilution. Results: All Extracts were effective against S.aureus ATCC 25923 growth; also Peganum harmala, Myrtus communis, Mentha pulegium, Mentha spp, and Zataria multiflora extracts were observed to have antimicrobial activity against E.coli ATCC 25922. This antimicrobial activity had partially similar results, comparing to conventional antibioticsConclusion: Medicinal plants produce various amounts of antimicrobial substances under the climatic and ecological conditions of each zone, which must be considered in manufacturing herbal medicines.

  6. Predicting weed problems in maize cropping by species distribution modelling

    Directory of Open Access Journals (Sweden)

    Bürger, Jana

    2014-02-01

    Full Text Available Increasing maize cultivation and changed cropping practices promote the selection of typical maize weeds that may also profit strongly from climate change. Predicting potential weed problems is of high interest for plant production. Within the project KLIFF, experiments were combined with species distribution modelling for this task in the region of Lower Saxony, Germany. For our study, we modelled ecological and damage niches of nine weed species that are significant and wide spread in maize cropping in a number of European countries. Species distribution models describe the ecological niche of a species, these are the environmental conditions under which a species can maintain a vital population. It is also possible to estimate a damage niche, i.e. the conditions under which a species causes damage in agricultural crops. For this, we combined occurrence data of European national data bases with high resolution climate, soil and land use data. Models were also projected to simulated climate conditions for the time horizon 2070 - 2100 in order to estimate climate change effects. Modelling results indicate favourable conditions for typical maize weed occurrence virtually all over the study region, but only a few species are important in maize cropping. This is in good accordance with the findings of an earlier maize weed monitoring. Reaction to changing climate conditions is species-specific, for some species neutral (E. crus-galli, other species may gain (Polygonum persicaria or loose (Viola arvensis large areas of suitable habitats. All species with damage potential under present conditions will remain important in maize cropping, some more species will gain regional importance (Calystegia sepium, Setara viridis.

  7. [Species composition and distribution of medical mollusca in Shanghai City].

    Science.gov (United States)

    Guo, Yun-hai; Lv, Shan; Gu, Wen-biao; Liu, He-xiang; Wu, Ying; Zhang, Yi

    2015-02-01

    To investigate the species diversity and distribution of medical mollusca in Shanghai City. From August 2012 to October 2013, all kinds of habitats in 8 districts and counties in Shanghai City, namely Jiading, Qingpu, Baoshan, Minhang, Songjiang, Jinshan, Chongming, Pudong, were selected for the field survey according to the distribution characteristics of the river system, and all the specimens of medical mollusca in the investigation sites were collected and classified by morphological identification. Meanwhile, the species composition, habitats as well as the fauna of the medical mollusca collected were analyzed. A total of 5,211 specimens were collected, which belonged to 2 classes, 14 families, 18 genera and 25 species, including Oncomelania hupensis hupensis, Pomacea canaliculata, Parafossarulus striatulus, Alocinma longicornis, Physa acuta, Galba pervia, Hippeutis cantori, etc. The species numbers of medical mollusca in Chongming, Jinshan, Pudong new area and Qingpu districts (counties) were 22, 22, 21 and 20, respectively, which were more than those of other areas. The habitat analysis suggested that the species numbers in the river and wetland were the most, both of which were 14 species. The main faunas of the medical mollusca in Shanghai were the cosmopolitan and oriental species. The freshwater gastropod species are paucity in Shanghai City, but almost of them can be served as the intermediate hosts of certain parasites to transmit snail-related parasitic diseases, so the surveillance of medical mollusca should be strengthened.

  8. Species Distribution modeling as a tool to unravel determinants of palm distribution in Thailand

    DEFF Research Database (Denmark)

    Tovaranonte, Jantrararuk; Barfod, Anders S.; Balslev, Henrik

    2011-01-01

    As a consequence of the decimation of the forest cover in Thailand from 50% to ca. 20 % since the 1950ies, it is difficult to gain insight in the drivers behind past, present and future distribution ranges of plant species. Species distribution modeling allows visualization of potential species...... distribution under specific sets of assumptions. In this study we used maximum entropy to map potential distributions of 103 species of palms for which more than 5 herbarium records exist. Palms constitute key-stone plant group from both an ecological, economical and conservation perspective. The models were......) and the Area Under the Curve (AUC). All models performed well with AUC scores above 0.95. The predicted distribution ranges showed high suitability for palms in the southern region of Thailand. It also shows that spatial predictor variables are important in cases where historical processes may explain extant...

  9. Species distribution models of tropical deep-sea snappers.

    Directory of Open Access Journals (Sweden)

    Céline Gomez

    Full Text Available Deep-sea fisheries provide an important source of protein to Pacific Island countries and territories that are highly dependent on fish for food security. However, spatial management of these deep-sea habitats is hindered by insufficient data. We developed species distribution models using spatially limited presence data for the main harvested species in the Western Central Pacific Ocean. We used bathymetric and water temperature data to develop presence-only species distribution models for the commercially exploited deep-sea snappers Etelis Cuvier 1828, Pristipomoides Valenciennes 1830, and Aphareus Cuvier 1830. We evaluated the performance of four different algorithms (CTA, GLM, MARS, and MAXENT within the BIOMOD framework to obtain an ensemble of predicted distributions. We projected these predictions across the Western Central Pacific Ocean to produce maps of potential deep-sea snapper distributions in 32 countries and territories. Depth was consistently the best predictor of presence for all species groups across all models. Bathymetric slope was consistently the poorest predictor. Temperature at depth was a good predictor of presence for GLM only. Model precision was highest for MAXENT and CTA. There were strong regional patterns in predicted distribution of suitable habitat, with the largest areas of suitable habitat (> 35% of the Exclusive Economic Zone predicted in seven South Pacific countries and territories (Fiji, Matthew & Hunter, Nauru, New Caledonia, Tonga, Vanuatu and Wallis & Futuna. Predicted habitat also varied among species, with the proportion of predicted habitat highest for Aphareus and lowest for Etelis. Despite data paucity, the relationship between deep-sea snapper presence and their environments was sufficiently strong to predict their distribution across a large area of the Pacific Ocean. Our results therefore provide a strong baseline for designing monitoring programs that balance resource exploitation and

  10. Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

    Science.gov (United States)

    Kastman, Erik K; Kamelamela, Noelani; Norville, Josh W; Cosetta, Casey M; Dutton, Rachel J; Wolfe, Benjamin E

    2016-10-18

    Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes. Decades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS

  11. Campylobacter Species Isolated from Pigs in Grenada Exhibited Novel Clones: Genotypes and Antimicrobial Resistance Profiles of Sequence Types.

    Science.gov (United States)

    Amadi, Victor A; Matthew-Belmar, Vanessa; Subbarao, Charmarthy; Kashoma, Isaac; Rajashekara, Gireesh; Sharma, Ravindra; Hariharan, Harry; Stone, Diana

    2017-07-01

    Infections caused by Campylobacter species pose a severe threat to public health worldwide. However, in Grenada, the occurrence and characteristics of Campylobacter in food animals, including pigs, remain mostly unknown. In this study, we identified the sequence types (STs) of Campylobacter from young healthy pigs in Grenada and compared the results with previous studies in Grenada and other countries. Antimicrobial resistance patterns and diversity of the Campylobacter clones were evaluated. Ninety-nine Campylobacter isolates (97 Campylobacter coli and 2 Campylobacter jejuni) were analyzed by multilocus sequence typing. Eighteen previously reported STs and 13 novel STs were identified. Of the 18 previously reported STs, eight STs (ST-854, -887, -1068, -1096, -1445, -1446, 1556, and -1579) have been associated with human gastroenteritis in different geographical regions. Among these 18 previously reported STs, ST-1428, -1096, -1450, and -1058 predominated and accounted for 18.2%, 14.1%, 11.1%, and 8.1% of all isolates, respectively. Of the 13 novel STs, ST-7675 predominated and accounted for 20% (4 of 20 isolates), followed by ST-7678, -7682, and -7691, each accounting for 10% (2 of 20 isolates). Antimicrobial resistance testing using Epsilometer test revealed a low resistance rate (1-3%) of all C. coli/jejuni STs to all antimicrobials except for tetracycline (1-10.1%). Some of the C. coli STs (13 STs, 24/99 isolates, 24.2%) were resistant to multiple antimicrobials. This is the first report on antimicrobial resistance and multidrug resistance patterns associated with Campylobacter STs recovered from swine in Grenada. This study showed that pigs in Grenada are not major reservoirs for STs of C. coli and C. jejuni that are associated with human gastroenteritis worldwide.

  12. How can model comparison help improving species distribution models?

    Directory of Open Access Journals (Sweden)

    Emmanuel Stephan Gritti

    Full Text Available Today, more than ever, robust projections of potential species range shifts are needed to anticipate and mitigate the impacts of climate change on biodiversity and ecosystem services. Such projections are so far provided almost exclusively by correlative species distribution models (correlative SDMs. However, concerns regarding the reliability of their predictive power are growing and several authors call for the development of process-based SDMs. Still, each of these methods presents strengths and weakness which have to be estimated if they are to be reliably used by decision makers. In this study we compare projections of three different SDMs (STASH, LPJ and PHENOFIT that lie in the continuum between correlative models and process-based models for the current distribution of three major European tree species, Fagussylvatica L., Quercusrobur L. and Pinussylvestris L. We compare the consistency of the model simulations using an innovative comparison map profile method, integrating local and multi-scale comparisons. The three models simulate relatively accurately the current distribution of the three species. The process-based model performs almost as well as the correlative model, although parameters of the former are not fitted to the observed species distributions. According to our simulations, species range limits are triggered, at the European scale, by establishment and survival through processes primarily related to phenology and resistance to abiotic stress rather than to growth efficiency. The accuracy of projections of the hybrid and process-based model could however be improved by integrating a more realistic representation of the species resistance to water stress for instance, advocating for pursuing efforts to understand and formulate explicitly the impact of climatic conditions and variations on these processes.

  13. Deriving field-based species sensitivity distributions (f-SSDs) from stacked species distribution models (S-SDMs).

    Science.gov (United States)

    Schipper, Aafke M; Posthuma, Leo; de Zwart, Dick; Huijbregts, Mark A J

    2014-12-16

    Quantitative relationships between species richness and single environmental factors, also called species sensitivity distributions (SSDs), are helpful to understand and predict biodiversity patterns, identify environmental management options and set environmental quality standards. However, species richness is typically dependent on a variety of environmental factors, implying that it is not straightforward to quantify SSDs from field monitoring data. Here, we present a novel and flexible approach to solve this, based on the method of stacked species distribution modeling. First, a species distribution model (SDM) is established for each species, describing its probability of occurrence in relation to multiple environmental factors. Next, the predictions of the SDMs are stacked along the gradient of each environmental factor with the remaining environmental factors at fixed levels. By varying those fixed levels, our approach can be used to investigate how field-based SSDs for a given environmental factor change in relation to changing confounding influences, including for example optimal, typical, or extreme environmental conditions. This provides an asset in the evaluation of potential management measures to reach good ecological status.

  14. Species distributions, quantum theory, and the enhancement of biodiversity measures

    DEFF Research Database (Denmark)

    Real, Raimundo; Barbosa, A. Márcia; Bull, Joseph William

    2017-01-01

    Species distributions are typically represented by records of their observed occurrence at a given spatial and temporal scale. Such records are inevitably incomplete and contingent on the spatial–temporal circumstances under which the observations were made. Moreover, organisms may respond...... biodiversity”. We show how conceptualizing species’ distributions in this way could help overcome important weaknesses in current biodiversity metrics, both in theory and by using a worked case study of mammal distributions in Spain over the last decade. We propose that considerable theoretical advances could...

  15. Five (or so) challenges for species distribution modelling

    DEFF Research Database (Denmark)

    Bastos Araujo, Miguel; Guisan, Antoine

    2006-01-01

    Species distribution modelling is central to both fundamental and applied research in biogeography. Despite widespread use of models, there are still important conceptual ambiguities as well as biotic and algorithmic uncertainties that need to be investigated in order to increase confidence in mo...

  16. Streptococcus pneumoniae from Palestinian nasopharyngeal carriers: serotype distribution and antimicrobial resistance.

    Directory of Open Access Journals (Sweden)

    Abedelmajeed Nasereddin

    Full Text Available Infections of Streptococcus pneumoniae in children can be prevented by vaccination; left untreated, they cause high morbidity and fatalities. This study aimed at determining the nasopharyngeal carrier rates, serotype distribution and antimicrobial resistance patterns of S. pneumoniae in healthy Palestinian children under age two prior to the full introduction of the pneumococcal 7-valent conjugate vaccine (PCV7, which was originally introduced into Palestine in a pilot trial in September, 2010. In a cross sectional study, nasopharyngeal specimens were collected from 397 healthy children from different Palestinian districts between the beginning of November 2012 to the end of January 2013. Samples were inoculated into blood agar and suspected colonies were examined by amplifying the pneumococcal-specific autolysin gene using a real-time PCR. Serotypes were identified by a PCR that incorporated different sets of specific primers. Antimicrobial susceptibility was measured by disk diffusion and MIC methods. The resulting carrier rate of Streptococcus pneumoniae was 55.7% (221/397. The main serotypes were PCV7 serotypes 19F (12.2%, 23F (9.0%, 6B (8.6% and 14 (4% and PCV13 serotypes 6A (13.6% and 19A (4.1%. Notably, serotype 6A, not included in the pilot trial (PCV7 vaccine, was the most prevalent. Resistance to more than two drugs was observed for bacteria from 34.1% of the children (72/211 while 22.3% (47/211 carried bacteria were susceptible to all tested antibiotics. All the isolates were sensitive to cefotaxime and vancomycin. Any or all of these might impinge on the type and efficacy of the pneumococcal conjugate vaccines and antibiotics to be used for prevention and treatment of pneumococcal disease in the country.

  17. VEGETATIVE MORPHOLOGY FOR SPECIES IDENTIFICATION OF TROPICAL TREES: FAMILY DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    Peter Hargreaves

    2006-03-01

    Full Text Available Tree specimens from the ESAL herbarium of the Universidade Federal de Lavras, Minas Gerais, Brazil, were describedby vegetative characteristics using CARipé, a Microsoft Access database application specially developed for this study. Only onespecimen per species was usually described. Thus, 2 observers described 567 herbarium species as a base to test methods ofidentification as part of a larger study. The present work formed part of that study and provides information on the distribution of22 vegetative characters among 16 families having 10 or more species described. The characters are discussed. The study foundmarked differences, even discontinuities, of distributions of characters between those families. Therefore it should be possible toincorporate phylogenetic relationships into the identification process.

  18. Molluscan indicator species and their potential use in ecological status assessment using species distribution modeling.

    Science.gov (United States)

    Moraitis, Manos L; Tsikopoulou, Irini; Geropoulos, Antonios; Dimitriou, Panagiotis D; Papageorgiou, Nafsika; Giannoulaki, Marianna; Valavanis, Vasilis D; Karakassis, Ioannis

    2018-05-24

    Marine habitat assessment using indicator species through Species Distribution Modeling (SDM) was investigated. The bivalves: Corbula gibba and Flexopecten hyalinus were the indicator species characterizing disturbed and undisturbed areas respectively in terms of chlorophyll a concentration in Greece. The habitat suitability maps of these species reflected the overall ecological status of the area. The C. gibba model successfully predicted the occurrence of this species in areas with increased physical disturbance driven by chlorophyll a concentration, whereas the habitat map for F. hyalinus showed an increased probability of occurrence in chlorophyll-poor areas, affected mainly by salinity. We advocate the use of C. gibba as a proxy for eutrophication and the incorporation of this species in monitoring studies through SDM methods. For the Mediterranean Sea we suggest the use of F. hyalinus in SDM as an indicator of environmental stability and a possible forecasting tool for salinity fluctuations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Antimicrobial resistance of Staphylococcus species isolated from Lebanese dairy-based products.

    Science.gov (United States)

    Zouhairi, O; Saleh, I; Alwan, N; Toufeili, I; Barbour, E; Harakeh, S

    2012-12-04

    The study evaluated the antimicrobial resistance of molecularly characterized strains of Staphylococcus aureus and S. saprophyticus isolated from 3 Lebanese dairy-based food products that are sometimes consumed raw: kishk, shanklish and baladi cheese. Suspected Staphylococcus isolates were identified initially using standard biochemical tests, then strains that were confirmed by polymerase chain reaction (29 S. aureus and 17 S. saprophyticus) were evaluated for their susceptibility to different antimicrobials. The highest levels of contamination with staphylococci were in baladi cheese. Resistance rates ranged from 67% to gentamicin to 94% to oxacillin and clindamycin. The results suggest that these locally made dairy-based foods may act as vehicles for the transmission of antimicrobial-resistant Staphylococcus spp.

  20. Epidemiological investigation and antimicrobial susceptibility analysis of ureaplasma species and Mycoplasma hominis in outpatients with genital manifestations.

    Science.gov (United States)

    Song, Tiejun; Ye, Aiqing; Xie, Xinyou; Huang, Jun; Ruan, Zhi; Kong, Yingying; Song, Jingjuan; Wang, Yue; Chen, Jiangzhong; Zhang, Jun

    2014-09-01

    The aim of this study was to assess the prevalence and drug resistance of Ureaplasma species and Mycoplasma hominis in outpatients with genital manifestation from 2005 to 2013 in Hangzhou, China. A total of 2689 female and 2336 male patients with various genital symptoms were included in this study. Species identification and antimicrobial susceptibility test were performed by using the mycoplasma IST-2 kit. The prevalence rate of Ureaplasma species was 39.9%, M hominis was 1.2% in female patients, and the coinfection rate was 13.4%; while in males, the prevalence rate of Ureaplasma species was 18.8%, M hominis was 0.4%, and the coinfection rate was 2.9%. Moreover, significantly high positive rates for mycoplasmas (Ureaplasma species M hominis) and were found in 16–20-year-old females (65.2%) and males (27.3%). Ureaplasma species and M hominis displayed relatively lower resistance rates (Ureaplasma species to quinolones (ofloxacin and ciprofloxacin) were much higher (>50%) and increased significantly from 2005 to 2013. Our study indicates that high positive rates of Ureaplasma species and M hominis were found in young outpatients with genital symptoms, and monitoring the local drug resistance is critical for prevention of the occurrence of resistant strains.

  1. An eight-year study of Shigella species in Beijing, China: serodiversity, virulence genes, and antimicrobial resistance.

    Science.gov (United States)

    Qu, Mei; Zhang, Xin; Liu, Guirong; Huang, Ying; Jia, Lei; Liang, Weili; Li, Xitai; Wu, Xiaona; Li, Jie; Yan, Hanqiu; Kan, Biao; Wang, Quanyi

    2014-07-14

    This study was conducted to determine the prevalence of serotypes, virulence factors, and antimicrobial resistance patterns of Shigella spp. in Beijing, China, from 2004 to 2011. Real-time PCR assays were used to detect virulent genes, and the Kirby-Bauer disk diffusion method was used to evaluate antimicrobial resistance. Among the total of 1,652 Shigella isolates, S. sonnei (57.1%) was the predominant species, followed by S. flexneri (42.3%), S. dysenteriae (0.4%), and S. boydii (0.2%). Nineteen serotypes were discovered among S. flexneri strains. The virulence gene ipaH was the most frequent, followed by sen and set. The presence of set showed significant difference in two dominant serogroups, S. flexneri and S. sonnei. Over 90% of Shigella isolates showed resistance to at least three drugs with widened spectrum. High-level antimicrobial resistance to single and multiple antibiotics was more common among S. sonnei than S. flexneri. There was an obvious serotype change and a dramatic increase of antibiotic resistance in Shigella prevalence in Beijing.

  2. SESAM – a new framework integrating macroecological and species distribution models for predicting spatio-temporal patterns of species assemblages

    DEFF Research Database (Denmark)

    Guisan, Antoine; Rahbek, Carsten

    2011-01-01

    Two different approaches currently prevail for predicting spatial patterns of species assemblages. The first approach (macroecological modelling, MEM) focuses directly on realized properties of species assemblages, whereas the second approach (stacked species distribution modelling, S-SDM) starts...

  3. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  4. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes 129 Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 129 Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, 129 Xe NMR is insensitive to fine structural details at room temperature

  5. Species-free species distribution models describe macroecological properties of protected area networks.

    Science.gov (United States)

    Robinson, Jason L; Fordyce, James A

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or "footprint") of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or have

  6. Antagonistic intestinal microflora produces antimicrobial substance inhibitory to pseudomonas species and other spoilage organisms

    NARCIS (Netherlands)

    Hatew, B.; Delessa, T.; Zakin, V.; Gollop, N.

    2011-01-01

    Chicken intestine harbors a vast number of bacterial strains. In the present study, antimicrobial substance produced by lactic acid bacteria (LAB) isolated from the gastrointestinal tract of healthy chicken was detected, characterized, and purified. Based on 16S rRNA sequencing, the bacteria were

  7. Antimicrobial activity of some selected species of genus .I.Nigella./I..

    Czech Academy of Sciences Publication Activity Database

    Kokoška, L.; Rada, V.; Vaněk, Tomáš; Nepovím, Aleš

    2002-01-01

    Roč. 2, Supl. 1 (2002), s. 180 ISSN 1576-0952. [Annual Congress of the Society for Medicinal Plant Research /50./. 08.09.2002-12.09.2002, Barcelona] R&D Projects: GA MŠk OC 843.10 Institutional research plan: CEZ:AV0Z4055905 Keywords : antimicrobial activity Subject RIV: EI - Biotechnology ; Bionics

  8. Evaluation of Antimicrobial and Anti-Inflammatory Activities of Seed Extracts from Six Nigella Species

    Czech Academy of Sciences Publication Activity Database

    Landa, Přemysl; Maršík, Petr; Havlík, J.; Klouček, P.; Vaněk, Tomáš; Kokoška, L.

    2009-01-01

    Roč. 12, č. 2 (2009), s. 408-415 ISSN 1096-620X R&D Projects: GA MŠk ME08070; GA ČR GP525/09/P528 Institutional research plan: CEZ:AV0Z50380511 Keywords : antimicrobial activity * cyclooxygenase-1 * cyclooxygenase-2 Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.390, year: 2009

  9. Antimicrobial susceptibility of Clostridium perfringens isolated from domestic and wild animal species in Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Augusto de Oliveira Júnior

    2016-02-01

    Full Text Available Clostridium perfringens is a microorganism commonly found in the microbiota of humans and animals and a potential cause of enteric, muscle or nervous diseases. The treatment of these diseases is based on antimicrobial therapy and it is extremely important to know the antimicrobial susceptibility profile of the strains present in the region. The aim of this study was to evaluate the antimicrobial susceptibility of C. perfringens isolated from domestic and wild animals in Brazil against seven different antimicrobials. Forty-one strains from the stool samples of cattle (n = 12, buffalo (n = 2, goat (n = 3, dogs (n = 12 and wild carnivores (n = 12 were examined. The minimum inhibitory concentration was determined by the agar dilution method using Brucella agar supplemented with 5% of sheep blood, 0.1% of vitamin K, 0.1% of hemin and concentrations ranging from 0,25 to 256,0 mg L-1 of the following antibiotics: erythromycin, florfenicol, metronidazole, oxytetracycline, penicillin, tylosin, and vancomycin. All C. perfringens strains were susceptible to florfenicol, metronidazole, penicillin and vancomycin. Two strains (4.9% were resistant to erythromycin and tylosin, while five (12.2% were resistant to oxytetracycline, one of which (2.4% from an ocelot.

  10. Biomimetic synthesis of antimicrobial silver nanoparticles using in vitro-propagated plantlets of a medicinally important endangered species: Phlomis bracteosa.

    Science.gov (United States)

    Anjum, Sumaira; Abbasi, Bilal Haider

    2016-01-01

    In vitro-derived cultures of plants offer a great potential for rapid biosynthesis of chemical-free antimicrobial silver nanoparticles (AgNPs) by enhancing their phytochemical reducing potential. Here, we developed an efficient protocol for in vitro micropropagation of a high-value endangered medicinal plant species, Phlomis bracteosa, in order to explore its biogenic potential in biomimetic synthesis of antimicrobial AgNPs. Murashige and Skoog medium supplemented with 2.0 mg/L thidiazuron was found to be more efficient in inducing optimum in vitro shoot regeneration (78%±4.09%), and 2.0 mg/L indole-3-butyric acid was used for maximum root induction (86%±4.457%). Antimicrobial AgNPs were successfully synthesized by using aqueous extract (rich in total phenolics and flavonoids content) of in vitro derived plantlets of P. bracteosa. Ultraviolet-visible spectroscopy of synthesized AgNPs showed characteristic surface plasmon band in the range of 420-429 nm. The crystallinity, size, and shape of the AgNPs were characterized by X-ray diffraction and scanning electron microscopy. Face-centered cubic AgNPs of almost uniform spherical size (22.41 nm) were synthesized within a short time (1 hour) at room temperature. Fourier-transform infrared spectroscopy revealed that the polyphenols were mainly responsible for reduction and capping of synthesized AgNPs. Energy dispersive X-ray analysis further endorsed the presence of elemental silver in synthesized AgNPs. These biosynthesized AgNPs displayed significantly higher bactericidal activity against multiple drug-resistant human pathogens. The present work highlighted the potent role of in vitro-derived plantlets of P. bracteosa for feasible biosynthesis of antimicrobial AgNPs, which can be used as nanomedicines in many biomedical applications.

  11. Bias correction in species distribution models: pooling survey and collection data for multiple species.

    Science.gov (United States)

    Fithian, William; Elith, Jane; Hastie, Trevor; Keith, David A

    2015-04-01

    Presence-only records may provide data on the distributions of rare species, but commonly suffer from large, unknown biases due to their typically haphazard collection schemes. Presence-absence or count data collected in systematic, planned surveys are more reliable but typically less abundant.We proposed a probabilistic model to allow for joint analysis of presence-only and survey data to exploit their complementary strengths. Our method pools presence-only and presence-absence data for many species and maximizes a joint likelihood, simultaneously estimating and adjusting for the sampling bias affecting the presence-only data. By assuming that the sampling bias is the same for all species, we can borrow strength across species to efficiently estimate the bias and improve our inference from presence-only data.We evaluate our model's performance on data for 36 eucalypt species in south-eastern Australia. We find that presence-only records exhibit a strong sampling bias towards the coast and towards Sydney, the largest city. Our data-pooling technique substantially improves the out-of-sample predictive performance of our model when the amount of available presence-absence data for a given species is scarceIf we have only presence-only data and no presence-absence data for a given species, but both types of data for several other species that suffer from the same spatial sampling bias, then our method can obtain an unbiased estimate of the first species' geographic range.

  12. The Combined Use of Correlative and Mechanistic Species Distribution Models Benefits Low Conservation Status Species.

    Directory of Open Access Journals (Sweden)

    Thibaud Rougier

    Full Text Available Species can respond to climate change by tracking appropriate environmental conditions in space, resulting in a range shift. Species Distribution Models (SDMs can help forecast such range shift responses. For few species, both correlative and mechanistic SDMs were built, but allis shad (Alosa alosa, an endangered anadromous fish species, is one of them. The main purpose of this study was to provide a framework for joint analyses of correlative and mechanistic SDMs projections in order to strengthen conservation measures for species of conservation concern. Guidelines for joint representation and subsequent interpretation of models outputs were defined and applied. The present joint analysis was based on the novel mechanistic model GR3D (Global Repositioning Dynamics of Diadromous fish Distribution which was parameterized on allis shad and then used to predict its future distribution along the European Atlantic coast under different climate change scenarios (RCP 4.5 and RCP 8.5. We then used a correlative SDM for this species to forecast its distribution across the same geographic area and under the same climate change scenarios. First, projections from correlative and mechanistic models provided congruent trends in probability of habitat suitability and population dynamics. This agreement was preferentially interpreted as referring to the species vulnerability to climate change. Climate change could not be accordingly listed as a major threat for allis shad. The congruence in predicted range limits between SDMs projections was the next point of interest. The difference, when noticed, required to deepen our understanding of the niche modelled by each approach. In this respect, the relative position of the northern range limit between the two methods strongly suggested here that a key biological process related to intraspecific variability was potentially lacking in the mechanistic SDM. Based on our knowledge, we hypothesized that local

  13. Distribution patterns of Saccharomyces species in cultural landscapes of Germany.

    Science.gov (United States)

    Brysch-Herzberg, Michael; Seidel, Martin

    2017-08-01

    The distribution patterns of the three Saccharomyces species, Saccharomyces paradoxus, S. uvarum and S. cerevisiae, were investigated by a culture-dependent approach in order to understand better how these species propagate in the cultural landscape of Germany. Saccharomyces paradoxus, the closest relative of S. cerevisiae, is shown to be a true woodland species. It was frequently found in the soil under conifers indicating that S. paradoxus is an autochthonous member of the microbial community in this habitat. Physiological characteristics of the species like the Crabtree effect and high tolerance against ethanol suggest that the species is adapted to regular supply with considerable amounts of sugars. Additionally, a high proportion of the S. paradoxus strains isolated in this study are shown to have the rare ability to ferment melezitose. For these reasons, it is hypothesized that S. paradoxus may be closely associated with the honeydew system in forests. Saccharomyces cerevisiae was rare in most habitats and only exceeded the frequency of S. paradoxus in habitats characterized by modern agricultural mass production of fruit. Both the landscape structure and the agricultural system heavily influence the frequencies of Saccharomyces species. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Species composition and geographical distribution of Saharan scorpion fauna, Morocco

    Directory of Open Access Journals (Sweden)

    Oulaid Touloun

    2016-11-01

    Full Text Available Objective: To describe the species composition of scorpions and to study its geographical distribution in Laayoune-Sakia El Hamra and Dakhla-Oued Ed Dahab regions in July 2014. Methods: To locate scorpions, the ground was examined through searching the places under the stones, rocks and in burrows. The nocturnal missions were also conducted using portable ultraviolet lamps. The scorpions were subsequently identified in the laboratory. Results: The results of the investigations in these regions showed the presence of five scorpion species, two of which Androctonus gonneti and Buthus bonito were endemic in Morocco. Conclusions: This work is allowed to complete the inventory of the studied scorpion fauna and provides some considerations on the distribution patterns in the study area.

  15. Mechanistic species distribution modeling reveals a niche shift during invasion.

    Science.gov (United States)

    Chapman, Daniel S; Scalone, Romain; Štefanić, Edita; Bullock, James M

    2017-06-01

    Niche shifts of nonnative plants can occur when they colonize novel climatic conditions. However, the mechanistic basis for niche shifts during invasion is poorly understood and has rarely been captured within species distribution models. We quantified the consequence of between-population variation in phenology for invasion of common ragweed (Ambrosia artemisiifolia L.) across Europe. Ragweed is of serious concern because of its harmful effects as a crop weed and because of its impact on public health as a major aeroallergen. We developed a forward mechanistic species distribution model based on responses of ragweed development rates to temperature and photoperiod. The model was parameterized and validated from the literature and by reanalyzing data from a reciprocal common garden experiment in which native and invasive populations were grown within and beyond the current invaded range. It could therefore accommodate between-population variation in the physiological requirements for flowering, and predict the potentially invaded ranges of individual populations. Northern-origin populations that were established outside the generally accepted climate envelope of the species had lower thermal requirements for bud development, suggesting local adaptation of phenology had occurred during the invasion. The model predicts that this will extend the potentially invaded range northward and increase the average suitability across Europe by 90% in the current climate and 20% in the future climate. Therefore, trait variation observed at the population scale can trigger a climatic niche shift at the biogeographic scale. For ragweed, earlier flowering phenology in established northern populations could allow the species to spread beyond its current invasive range, substantially increasing its risk to agriculture and public health. Mechanistic species distribution models offer the possibility to represent niche shifts by varying the traits and niche responses of individual

  16. Mechanisms controlling the distribution of two invasive Bromus species

    Directory of Open Access Journals (Sweden)

    Olga Bykova

    2014-03-01

    Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.

  17. Drought tolerance of tropical tree species : functional traits, trade-offs and species distribution

    NARCIS (Netherlands)

    Markesteijn, L.

    2010-01-01

    KEY-WORDS:
    Bolivia, drought tolerance, shade tolerance, functional traits, trade-offs, ecophysiology, species distribution
    Tropical forests occur under rainfall regimes that vary greatly in the rainfall pattern and frequency and intensity of drought. Consequently water availability is

  18. Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

    Science.gov (United States)

    Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

    2012-01-01

    The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

  19. Antimicrobial-resistant Klebsiella species isolated from free-range chicken samples in an informal settlement.

    Science.gov (United States)

    Fielding, Burtram C; Mnabisa, Amanda; Gouws, Pieter A; Morris, Thureyah

    2012-02-29

    Sub-therapeutic doses of antimicrobial agents are administered routinely to poultry to aid growth and to prevent disease, with prolonged exposure often resulting in bacterial resistance. Crossover of antibiotic resistant bacteria from poultry to humans poses a risk to human health. In this study, 17 chicken samples collected from a vendor operating in an informal settlement in the Cape Town Metropolitan area, South Africa were screened for antimicrobial-resistant Gram-negative bacilli using the Kirby Bauer disk diffusion assay. IN TOTAL, SIX ANTIBIOTICS WERE SCREENED: ampicillin, ciprofloxacin, gentamicin, nalidixic acid, tetracycline and trimethoprim. Surprisingly, Klebsiella ozaenae was identified in 96 and K. rhinoscleromatis in 6 (n=102) of the samples tested. Interestingly, ∼40% of the isolated Klebsiella spp. showed multiple resistance to at least three of the six antibiotics tested. Klebsiella ozaenae and K. rhinoscleromatis cause clinical chronic rhinitis and are almost exclusively associated with people living in areas of poor hygiene.

  20. Cytotoxic and Antimicrobial Compounds from the Marine-Derived Fungus, Penicillium Species

    Directory of Open Access Journals (Sweden)

    Diaa T. A. Youssef

    2018-02-01

    Full Text Available The organic extract of liquid cultures of the marine-derived Penicillium sp. was investigated. Fractionation of the extracts of the fungus led to the purification and identification of two new compounds, penicillatides A (1 and B (2, together with the previously reported cyclo(R-Pro–S-Phe (3 and cyclo(R-Pro–R-Phe (4. The structures of compounds 1–4 were assigned by extensive interpretation of their NMR and high-resolution mass spectrometry (HRMS. The antiproliferative and cytotoxic activities of the compounds against three human cancer cell lines as well as their antimicrobial activity against several pathogens were evaluated. Compounds 2–4 displayed variable cytotoxic and antimicrobial activities.

  1. In vitro anti-microbial activity of extracts from the callus cultures of some Nigella species

    Czech Academy of Sciences Publication Activity Database

    Landa, P.; Maršík, Petr; Vaněk, Tomáš; Rada, V.; Kokoška, L.

    2006-01-01

    Roč. 61, č. 3 (2006), s. 285-288 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA525/02/0257; GA MŠk(CZ) 1P04OC926.001 Institutional research plan: CEZ:AV0Z40550506 Keywords : Nigella * callus culture * antimicrobial activity Subject RIV: CC - Organic Chemistry Impact factor: 0.213, year: 2006

  2. Prevalence and antimicrobial resistance of Campylobacter species isolated from chicken carcasses during processing in Iran.

    Science.gov (United States)

    Rahimi, E; Momtaz, H; Ameri, M; Ghasemian-Safaei, H; Ali-Kasemi, M

    2010-05-01

    The objective of this study was to determine the prevalence and antimicrobial resistance of Campylobacter spp. isolated from chicken carcasses during different stages of broiler processing in a major commercial poultry processing plant in southwestern Iran. Overall, 84 chicken carcasses were sampled from 4 sites along the processing line during a total of 7 visits. In addition, 14 water samples from the chiller tank were taken. Using the cultural method, 186 of 336 (55.4%) carcasses were positive for Campylobacter. Campylobacter jejuni was more frequently isolated (89.4%) than Campylobacter coli (10.6%). The frequency of Campylobacter spp. on carcasses was 54.8% after defeathering, 51.2% after evisceration, 69.0% 20 min after the chilling period started, and 46.4% 24 h after the chilling period completed. Campylobacter was positive in 85.7% of the samples taken from the chilling water. The frequency of Campylobacter spp.-positive carcasses was reduced in complete chilled chickens but not during the slaughtering process. Susceptibilities of Campylobacter isolates were determined for 10 antimicrobial drugs using the disk diffusion method. Of the 198 Campylobacter isolates tested, 92.9% were resistant to one or more antimicrobial agents. Resistance to tetracycline was the most common finding (78.3%), followed by resistance to ciprofloxacin (62.1%), nalidixic acid (58.6%), and enrofloxacin (44.4%).

  3. In vitro antimicrobial activity and antagonistic effect of essential oils from plant species.

    Science.gov (United States)

    Toroglu, Sevil

    2007-07-01

    Kahramanmaras, is a developing city located in the southern part of Turkey Thymus eigii (M. Zohary and RH. Davis) Jalas, Pinus nigraAm. sub sp pallasiana and Cupressus sempervirens L. are the useful plants of the Kahramanmaras province and have been understudy since 2004 for the traditional uses of plants empiric drug, spice, herbal tea industry herbal gum and fuel. The study was designed to examine the antimicrobial activities of essential oils of these plants by the disc diffusion and minimum inhibitory concentration (MIC) methods. In addition, antimicrobial activity of Thymus eigii was researched by effects when it was used together with antibiotics and even when it was combined with other essential oils. When the results of this study were compared with vancomycin (30 mcg) and erytromycin (15 mcg) standards, it was found that Thymus eigii essential oil was particularly found to possess strongerantimicrobial activity whereas other essential oils showed susceptible or moderate activity However, antimicrobial activity changed also by in vitro interactions between antibiotics and Thymus eigii essential oil, also between essential oils of these plants and that of Thymus eigii causing synergic, additive, antagonist effect.

  4. Response of chironomid species (Diptera, Chironomidae to water temperature: effects on species distribution in specific habitats

    Directory of Open Access Journals (Sweden)

    L. Marziali

    2013-09-01

    Full Text Available The response of 443 chironomid species to water temperature was analyzed, with the aim of defining their thermal optimum, tolerance limits and thermal habitat. The database included 4442 samples mainly from Italian river catchments collected from the 1950s up to date. Thermal preferences were calculated separately for larval and pupal specimens and for different habitats: high altitude and lowland lakes in the Alpine ecoregion; lowland lakes in the Mediterranean ecoregion; heavily modified water bodies; kryal, krenal, rhithral and potamal in running waters. Optimum response was calculated as mean water temperature, weighted by species abundances; tolerance as weighted standard deviation; skewness and kurtosis as 3rd and 4th moment statistics. The responses were fitted to normal uni- or plurimodal Gaussian models. Cold stenothermal species showed: i unimodal response, ii tolerance for a narrow temperature range, iii optima closed to their minimum temperature values, iv leptokurtic response. Thermophilous species showed: i optima at different temperature values, ii wider tolerance, iii optima near their maximum temperature values, iv platikurtic response, often fitting a plurimodal model. As expected, lower optima values and narrower tolerance were obtained for kryal and krenal, than for rhithral, potamal and lakes. Thermal response curves were produced for each species and were discussed according to species distribution (i.e. altitudinal range in running water and water depth in lakes, voltinism and phylogeny. Thermal optimum and tolerance limits and the definition of the thermal habitat of species can help predicting the impact of global warming on freshwater ecosystems.

  5. Do predictions from Species Sensitivity Distributions match with field data?

    International Nuclear Information System (INIS)

    Smetanová, S.; Bláha, L.; Liess, M.; Schäfer, R.B.; Beketov, M.A.

    2014-01-01

    Species Sensitivity Distribution (SSD) is a statistical model that can be used to predict effects of contaminants on biological communities, but only few comparisons of this model with field studies have been conducted so far. In the present study we used measured pesticides concentrations from streams in Germany, France, and Finland, and we used SSD to calculate msPAF (multiple substance potentially affected fraction) values based on maximum toxic stress at localities. We compared these SSD-based predictions with the actual effects on stream invertebrates quantified by the SPEAR pesticides bioindicator. The results show that the msPAFs correlated well with the bioindicator, however, the generally accepted SSD threshold msPAF of 0.05 (5% of species are predicted to be affected) severely underestimated the observed effects (msPAF values causing significant effects are 2–1000-times lower). These results demonstrate that validation with field data is required to define the appropriate thresholds for SSD predictions. - Highlights: • We validated the statistical model Species Sensitivity Distribution with field data. • Good correlation was found between the model predictions and observed effects. • But, the generally accepted threshold msPAF 0.05 severely underestimated the effects. - Comparison of the SSD-based prediction with the field data evaluated with the SPEAR pesticides index shows that SSD threshold msPAF of 0.05 severely underestimates the effects observed in the field

  6. Projecting future expansion of invasive species: comparing and improving methodologies for species distribution modeling.

    Science.gov (United States)

    Mainali, Kumar P; Warren, Dan L; Dhileepan, Kunjithapatham; McConnachie, Andrew; Strathie, Lorraine; Hassan, Gul; Karki, Debendra; Shrestha, Bharat B; Parmesan, Camille

    2015-12-01

    Modeling the distributions of species, especially of invasive species in non-native ranges, involves multiple challenges. Here, we developed some novel approaches to species distribution modeling aimed at reducing the influences of such challenges and improving the realism of projections. We estimated species-environment relationships for Parthenium hysterophorus L. (Asteraceae) with four modeling methods run with multiple scenarios of (i) sources of occurrences and geographically isolated background ranges for absences, (ii) approaches to drawing background (absence) points, and (iii) alternate sets of predictor variables. We further tested various quantitative metrics of model evaluation against biological insight. Model projections were very sensitive to the choice of training dataset. Model accuracy was much improved using a global dataset for model training, rather than restricting data input to the species' native range. AUC score was a poor metric for model evaluation and, if used alone, was not a useful criterion for assessing model performance. Projections away from the sampled space (i.e., into areas of potential future invasion) were very different depending on the modeling methods used, raising questions about the reliability of ensemble projections. Generalized linear models gave very unrealistic projections far away from the training region. Models that efficiently fit the dominant pattern, but exclude highly local patterns in the dataset and capture interactions as they appear in data (e.g., boosted regression trees), improved generalization of the models. Biological knowledge of the species and its distribution was important in refining choices about the best set of projections. A post hoc test conducted on a new Parthenium dataset from Nepal validated excellent predictive performance of our 'best' model. We showed that vast stretches of currently uninvaded geographic areas on multiple continents harbor highly suitable habitats for parthenium

  7. Effects of urbanization on carnivore species distribution and richness

    Science.gov (United States)

    Ordenana, Miguel A.; Crooks, Kevin R.; Boydston, Erin E.; Fisher, Robert N.; Lyren, Lisa M.; Siudyla, Shalene; Haas, Christopher D.; Harris, Sierra; Hathaway, Stacie A.; Turschak, Greta M.; Miles, A. Keith; Van Vuren, Dirk H.

    2010-01-01

    Urban development can have multiple effects on mammalian carnivore communities. We conducted a meta-analysis of 7,929 photographs from 217 localities in 11 camera-trap studies across coastal southern California to describe habitat use and determine the effects of urban proximity (distance to urban edge) and intensity (percentage of area urbanized) on carnivore occurrence and species richness in natural habitats close to the urban boundary. Coyotes (Canis latrans) and bobcats (Lynx rufus) were distributed widely across the region. Domestic dogs (Canis lupus familiaris), striped skunks (Mephitis mephitis), raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), mountain lions (Puma concolor), and Virginia opossums (Didelphis virginiana) were detected less frequently, and long-tailed weasels (Mustela frenata), American badgers (Taxidea taxus), western spotted skunks (Spilogale gracilis), and domestic cats (Felis catus) were detected rarely. Habitat use generally reflected availability for most species. Coyote and raccoon occurrence increased with both proximity to and intensity of urbanization, whereas bobcat, gray fox, and mountain lion occurrence decreased with urban proximity and intensity. Domestic dogs and Virginia opossums exhibited positive and weak negative relationships, respectively, with urban intensity but were unaffected by urban proximity. Striped skunk occurrence increased with urban proximity but decreased with urban intensity. Native species richness was negatively associated with urban intensity but not urban proximity, probably because of the stronger negative response of individual species to urban intensity.

  8. Regional climate model downscaling may improve the prediction of alien plant species distributions

    Science.gov (United States)

    Liu, Shuyan; Liang, Xin-Zhong; Gao, Wei; Stohlgren, Thomas J.

    2014-12-01

    Distributions of invasive species are commonly predicted with species distribution models that build upon the statistical relationships between observed species presence data and climate data. We used field observations, climate station data, and Maximum Entropy species distribution models for 13 invasive plant species in the United States, and then compared the models with inputs from a General Circulation Model (hereafter GCM-based models) and a downscaled Regional Climate Model (hereafter, RCM-based models).We also compared species distributions based on either GCM-based or RCM-based models for the present (1990-1999) to the future (2046-2055). RCM-based species distribution models replicated observed distributions remarkably better than GCM-based models for all invasive species under the current climate. This was shown for the presence locations of the species, and by using four common statistical metrics to compare modeled distributions. For two widespread invasive taxa ( Bromus tectorum or cheatgrass, and Tamarix spp. or tamarisk), GCM-based models failed miserably to reproduce observed species distributions. In contrast, RCM-based species distribution models closely matched observations. Future species distributions may be significantly affected by using GCM-based inputs. Because invasive plants species often show high resilience and low rates of local extinction, RCM-based species distribution models may perform better than GCM-based species distribution models for planning containment programs for invasive species.

  9. Distribution of Plasmids in Distinct Leptospira Pathogenic Species.

    Science.gov (United States)

    Wang, Yanzhuo; Zhuang, Xuran; Zhong, Yi; Zhang, Cuicai; Zhang, Yan; Zeng, Lingbing; Zhu, Yongzhang; He, Ping; Dong, Ke; Pal, Utpal; Guo, Xiaokui; Qin, Jinhong

    2015-11-01

    Leptospirosis, caused by pathogenic Leptospira, is a worldwide zoonotic infection. The genus Leptospira includes at least 21 species clustered into three groups--pathogens, non-pathogens, and intermediates--based on 16S rRNA phylogeny. Research on Leptospira is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in L. interrogans has provided new insight into genome complexity of the genus Leptospira. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in L. borgpetersenii serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of Leptospira, comprising L. borgpetersenii, L. weilii, and L. interrogans, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-rep, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-rep probe and 11 with the lcp2-rep probe, whereas two can hybridize with the lcp3-rep probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-rep genes with a nonredundant protein database of Leptospira species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in Leptospira species, and further elucidation of their biological

  10. Species distribution modelling for conservation of an endangered endemic orchid.

    Science.gov (United States)

    Wang, Hsiao-Hsuan; Wonkka, Carissa L; Treglia, Michael L; Grant, William E; Smeins, Fred E; Rogers, William E

    2015-04-21

    Concerns regarding the long-term viability of threatened and endangered plant species are increasingly warranted given the potential impacts of climate change and habitat fragmentation on unstable and isolated populations. Orchidaceae is the largest and most diverse family of flowering plants, but it is currently facing unprecedented risks of extinction. Despite substantial conservation emphasis on rare orchids, populations continue to decline. Spiranthes parksii (Navasota ladies' tresses) is a federally and state-listed endangered terrestrial orchid endemic to central Texas. Hence, we aimed to identify potential factors influencing the distribution of the species, quantify the relative importance of each factor and determine suitable habitat for future surveys and targeted conservation efforts. We analysed several geo-referenced variables describing climatic conditions and landscape features to identify potential factors influencing the likelihood of occurrence of S. parksii using boosted regression trees. Our model classified 97 % of the cells correctly with regard to species presence and absence, and indicated that probability of existence was correlated with climatic conditions and landscape features. The most influential variables were mean annual precipitation, mean elevation, mean annual minimum temperature and mean annual maximum temperature. The most likely suitable range for S. parksii was the eastern portions of Leon and Madison Counties, the southern portion of Brazos County, a portion of northern Grimes County and along the borders between Burleson and Washington Counties. Our model can assist in the development of an integrated conservation strategy through: (i) focussing future survey and research efforts on areas with a high likelihood of occurrence, (ii) aiding in selection of areas for conservation and restoration and (iii) framing future research questions including those necessary for predicting responses to climate change. Our model could also

  11. CHEMICAL CHARACTERIZATION OF Lavandula angustifolia Mill. WHICH IS A PHYTOCOSMETIC SPECIES AND INVESTIGATION OF ITS ANTIMICROBIAL EFFECT IN COSMETIC PRODUCTS

    Directory of Open Access Journals (Sweden)

    Aslıhan Cesur Turgut

    2016-11-01

    Full Text Available Lavander (Lavandula sp. is a precious essential oil plant from the Lamiaceae family. There are 39 lavender species (Lavandula sp. most of which have Mediterranean origin and among them three have high commercial value. While the essential oil quality of the lavender species (British lavender is high the lavandin species (hybrid lavender have high essential oil yield [2, 52]. In this study, the content of the extracts obtained from Lavandula angustifolia, which were grown in Burdur Örtülü locality, was determined via HPLC and GC analysis and the anti-microbial effect of the essential oil L. angustifolia was investigated. The study was made with the dried flowers of L. angustifolia. Some of the dried flowers were extracted and the essential oil was distilled from the remaining part. Various phenolic compounds in the extract were quantitatively determined by HPLC. Quantitatively cafeic, rosemeric and the 4-hydroxybenzoic acids were the most abundant phenolic acids in the content in decreasing order. In the GC analysis 31 different compounds were determined: Linalool and Linalil Acetate having the highest concentration. Anti-microbial effect was determined against the most frequently encountered microorganisms in the cosmetics: Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus brasiliensis. According to the results it is concluded that the essential oil, L. angustifolia, can be used either directly or incorporated into the cosmetics without the necessity for any other extra preservative against the said microrganisms. According to the literature these microorganisms, which are frequently found in creams, cause various diseases. It was observed that the essential oil L. Angustifolia could completely remove the contamination caused by the said micro-organisms as of the 14. day.

  12. Isolation and antimicrobial acitivity of anthraquinones from some species of the lichen genus Xanthoria

    Directory of Open Access Journals (Sweden)

    LJ. KRSTIC

    2000-08-01

    Full Text Available The isolation of six anthraquinones, erythroglaucin, physcion, xanthorin, emodin, fallacinal and teloschistin, from three species of the lichen genus Xanthoria (X. fallax, X. elegans and X. policarpa is reported. Physcion is the dominant anthraquinone in all species. the anthraquinones showed broad-spectrum antifingal activity and selective activity against some phytopathogenic bacterial species.

  13. The Freshwater Sponge Ephydatia fluviatilis Harbours Diverse Pseudomonas Species (Gammaproteobacteria, Pseudomonadales) with Broad-Spectrum Antimicrobial Activity

    Science.gov (United States)

    Keller-Costa, Tina; Jousset, Alexandre; van Overbeek, Leo; van Elsas, Jan Dirk; Costa, Rodrigo

    2014-01-01

    Bacteria are believed to play an important role in the fitness and biochemistry of sponges (Porifera). Pseudomonas species (Gammaproteobacteria, Pseudomonadales) are capable of colonizing a broad range of eukaryotic hosts, but knowledge of their diversity and function in freshwater invertebrates is rudimentary. We assessed the diversity, structure and antimicrobial activities of Pseudomonas spp. in the freshwater sponge Ephydatia fluviatilis. Polymerase Chain Reaction – Denaturing Gradient Gel Electrophoresis (PCR-DGGE) fingerprints of the global regulator gene gacA revealed distinct structures between sponge-associated and free-living Pseudomonas communities, unveiling previously unsuspected diversity of these assemblages in freshwater. Community structures varied across E. fluviatilis specimens, yet specific gacA phylotypes could be detected by PCR-DGGE in almost all sponge individuals sampled over two consecutive years. By means of whole-genome fingerprinting, 39 distinct genotypes were found within 90 fluorescent Pseudomonas isolates retrieved from E. fluviatilis. High frequency of in vitro antibacterial (49%), antiprotozoan (35%) and anti-oomycetal (32%) activities was found among these isolates, contrasting less-pronounced basidiomycetal (17%) and ascomycetal (8%) antagonism. Culture extracts of highly predation-resistant isolates rapidly caused complete immobility or lysis of cells of the protozoan Colpoda steinii. Isolates tentatively identified as P. jessenii, P. protegens and P. oryzihabitans showed conspicuous inhibitory traits and correspondence with dominant sponge-associated phylotypes registered by cultivation-independent analysis. Our findings suggest that E. fluviatilis hosts both transient and persistent Pseudomonas symbionts displaying antimicrobial activities of potential ecological and biotechnological value. PMID:24533086

  14. Salmonella Species' Persistence and Their High Level of Antimicrobial Resistance in Flooded Man-Made Rivers in China.

    Science.gov (United States)

    Song, Qifa; Zhang, Danyang; Gao, Hong; Wu, Junhua

    2018-05-11

    Man-made rivers, owing to proximity to human habitats, facilitate transmission of salmonellosis to humans. To determine the contamination situation by Salmonella in flooded man-made rivers and thereafter the exposure risk to public health, we investigated the prevalence of Salmonella species and their antimicrobial resistance in such rivers, as well as the relationship between the incidence of local infectious diarrhea cases and the number of Salmonella isolates from patients. After a heavy flood, 95 isolates of 13 Salmonella serotypes were isolated from 80 river water samples. The two most prevalent serotypes were Typhimurium and Derby. Eight Salmonella serotypes were newly detected after the flood. Overall, 50 isolates were resistant to ampicillin and/or cefotaxime and carried at least bla TEM . Twelve isolates of serotypes Typhimurium, Derby, Rissen, and Indiana were extended-spectrum β-lactamase (ESBL) producing and carried at least one of bla OXA and bla CTX-M-like genes. Twelve isolates of serotypes Typhimurium, Derby, Agona, Rissen, and Indiana were resistant to ciprofloxacin and had gyrA mutations. Isolates of Typhimurium, Derby, and Indiana were concurrently ciprofloxacin resistant and ESBL producing. Pulsed-field gel electrophoresis illustrates the circulation of two dominant clones of Salmonella Typhimurium isolates among patients, river, and food. High prevalence of various highly pathogenic and antimicrobial-resistant Salmonella serotypes shows that man-made rivers are prone to heavy contamination with Salmonella, and as a result put public health at greater risk.

  15. Antimicrobial susceptibility pattern of Acinetobacter species isolated from infected wounds at a tertiary care hospital

    Directory of Open Access Journals (Sweden)

    Rosić Ivana

    2013-01-01

    Full Text Available Bacteria of the genus Acinetobacter, especially species Acinetobacter baumanii, is one of the most important causes of infection in immunocompromised patients in hospital. The aim of this study was to determine susceptibility of Acinetobacter species isolated from swabs of inflamed wounds to antibiotics. The study was conducted in several departments of the Clinical Centre 'Kragujevac' through retrospective analysis of 220 Acinetobacter species isolates from surgical wounds in 2011. The isolates of Acinetobaster species were mostly sensitive to ampicillin-sulbactam, colistin and tigecycline in all hospital departments that were surveyed. Only minority of the isolated Acinetobacter species were susceptible to cotrimoxazole, amikacin, imipenem and/or meropenem. Antibiotics with the highest in vitro efficacy against Acinetobacter species were ampicillinsulbactam, colistin and tigecycline. Highly resistant Acinetobacter species were more frequently isolated from patients in Intensive Care Unit.

  16. Effects of species biological traits and environmental heterogeneity on simulated tree species distribution shifts under climate change.

    Science.gov (United States)

    Wang, Wen J; He, Hong S; Thompson, Frank R; Spetich, Martin A; Fraser, Jacob S

    2018-09-01

    Demographic processes (fecundity, dispersal, colonization, growth, and mortality) and their interactions with environmental changes are not well represented in current climate-distribution models (e.g., niche and biophysical process models) and constitute a large uncertainty in projections of future tree species distribution shifts. We investigate how species biological traits and environmental heterogeneity affect species distribution shifts. We used a species-specific, spatially explicit forest dynamic model LANDIS PRO, which incorporates site-scale tree species demography and competition, landscape-scale dispersal and disturbances, and regional-scale abiotic controls, to simulate the distribution shifts of four representative tree species with distinct biological traits in the central hardwood forest region of United States. Our results suggested that biological traits (e.g., dispersal capacity, maturation age) were important for determining tree species distribution shifts. Environmental heterogeneity, on average, reduced shift rates by 8% compared to perfect environmental conditions. The average distribution shift rates ranged from 24 to 200myear -1 under climate change scenarios, implying that many tree species may not able to keep up with climate change because of limited dispersal capacity, long generation time, and environmental heterogeneity. We suggest that climate-distribution models should include species demographic processes (e.g., fecundity, dispersal, colonization), biological traits (e.g., dispersal capacity, maturation age), and environmental heterogeneity (e.g., habitat fragmentation) to improve future predictions of species distribution shifts in response to changing climates. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Sapling performance along resource gradients drives tree species distributions within and across tropical forests

    NARCIS (Netherlands)

    Sterck, F.J.; Markesteijn, L.; Toledo, M.; Schieving, F.; Poorter, L.

    2014-01-01

    Niche differentiation is a major hypothesized determinant of species distributions, but its practical importance is heavily debated and its underlying mechanisms are poorly understood. Trait-based approaches have been used to infer niche differentiation and predict species distributions. For

  18. New packaging design for fresh produce with effective distribution of antimicrobial gaseous chlorine dioxide

    Science.gov (United States)

    In the last decade, the potential use of chlorine dioxide (ClO2) as an antimicrobial agent for vapor-phase decontamination to extend the shelf-life of fresh produce has been widely studied. Most of the works focused on the dose of gaseous ClO2 for particular food product and/or specific microorganis...

  19. Breeding Hedychium Species, Ornamental Ginger Plants with Insecticidal and Anti-Microbial Activities

    Science.gov (United States)

    Hedychium species belong to the ginger family with great potential as ornamentals, but lodging is an impediment to this possibility, so there is a need for more compact Hedychium cultivars. Hedychium muluense (diploid) is one of the few dwarf species, but it is not ornamentally as attractive as som...

  20. Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils.

    Science.gov (United States)

    Khoury, Madona; Stien, Didier; Eparvier, Véronique; Ouaini, Naïm; El Beyrouthy, Marc

    2016-01-01

    Many Lamiaceae species are consumed in the Lebanese cuisine as food or condiment and are largely used in the traditional medicine of Lebanon to treat various diseases, including microbial infections. In this article we report the traditional medicinal uses of eleven Lamiaceae species: Coridothymus capitatus L., Lavandula stoechas L., Lavandula angustifolia Mill., Mentha spicata L. subsp. condensata , Origanum syriacum L., Rosmarinus officinalis , Salvia fruticosa Miller., Satureja cuneifolia Ten., Satureja thymbra L., Thymbra spicata L., and Vitex agnus-castus L. and study the chemical composition and antimicrobial activity of their essential oils (EOs). Our survey showed that Lamiaceae species are mainly used against gastrointestinal disorders and microbial infections. Chemical analysis of the EOs obtained from these plants allowed us to identify seventy-five compounds describing more than 90% of the relative composition of each EO. Essential oils with high amounts of thymol and carvacrol possessed the strongest antimicrobial activity. As expected, these two compounds demonstrated an interesting antifungal efficacy against the filamentous fungus T. rubrum . Our results confirmed that some of the Lamiaceae species used in Lebanon ethnopharmacological practices as antimicrobial agents do possess antibacterial and antifungal potential consistent with their use in alternative or complementary medicine.

  1. Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils

    Science.gov (United States)

    Khoury, Madona; Eparvier, Véronique; Ouaini, Naïm

    2016-01-01

    Many Lamiaceae species are consumed in the Lebanese cuisine as food or condiment and are largely used in the traditional medicine of Lebanon to treat various diseases, including microbial infections. In this article we report the traditional medicinal uses of eleven Lamiaceae species: Coridothymus capitatus L., Lavandula stoechas L., Lavandula angustifolia Mill., Mentha spicata L. subsp. condensata, Origanum syriacum L., Rosmarinus officinalis, Salvia fruticosa Miller., Satureja cuneifolia Ten., Satureja thymbra L., Thymbra spicata L., and Vitex agnus-castus L. and study the chemical composition and antimicrobial activity of their essential oils (EOs). Our survey showed that Lamiaceae species are mainly used against gastrointestinal disorders and microbial infections. Chemical analysis of the EOs obtained from these plants allowed us to identify seventy-five compounds describing more than 90% of the relative composition of each EO. Essential oils with high amounts of thymol and carvacrol possessed the strongest antimicrobial activity. As expected, these two compounds demonstrated an interesting antifungal efficacy against the filamentous fungus T. rubrum. Our results confirmed that some of the Lamiaceae species used in Lebanon ethnopharmacological practices as antimicrobial agents do possess antibacterial and antifungal potential consistent with their use in alternative or complementary medicine. PMID:28053641

  2. Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils

    Directory of Open Access Journals (Sweden)

    Madona Khoury

    2016-01-01

    Full Text Available Many Lamiaceae species are consumed in the Lebanese cuisine as food or condiment and are largely used in the traditional medicine of Lebanon to treat various diseases, including microbial infections. In this article we report the traditional medicinal uses of eleven Lamiaceae species: Coridothymus capitatus L., Lavandula stoechas L., Lavandula angustifolia Mill., Mentha spicata L. subsp. condensata, Origanum syriacum L., Rosmarinus officinalis, Salvia fruticosa Miller., Satureja cuneifolia Ten., Satureja thymbra L., Thymbra spicata L., and Vitex agnus-castus L. and study the chemical composition and antimicrobial activity of their essential oils (EOs. Our survey showed that Lamiaceae species are mainly used against gastrointestinal disorders and microbial infections. Chemical analysis of the EOs obtained from these plants allowed us to identify seventy-five compounds describing more than 90% of the relative composition of each EO. Essential oils with high amounts of thymol and carvacrol possessed the strongest antimicrobial activity. As expected, these two compounds demonstrated an interesting antifungal efficacy against the filamentous fungus T. rubrum. Our results confirmed that some of the Lamiaceae species used in Lebanon ethnopharmacological practices as antimicrobial agents do possess antibacterial and antifungal potential consistent with their use in alternative or complementary medicine.

  3. Distribution of Studied Insectivorous Bat Species of Myanmar

    International Nuclear Information System (INIS)

    Nyo Nyo

    2005-10-01

    Fourty-five species of insectivourous bats; Craseonycteris thonglongyai, Emballonura monticola, Taphozous melenopongon, T. theobaldi, T. longimanus, Megaderma lyra, M. spasma, Rhinolophus affinis, R. rouxii, R. pusillus, R. lepidus, R. macrotis, R. trifoliatus, R. pearsoni, R. malayanus, R. stheno, R. thomasi, R. shameli, R. acuminatus, R. marshalli, Rhinolophus sp., Hipposideros pomona, H. larvatus, H. armiger, H. lylei, H. ater, H. fulvus, Aselliscus stoliczkanus, Tadarida plicata, Myotis siligorensis, M. muricola, M. horsfieldii, M. hasseltii, M. chinensis, Scotophilus heathii, S. kuhlii, Ia io, Pipistrellus javanicus, P. coromandra, P. pulveratus, P. paterculus, P. affinis, P. ceylonicus, Miniopterus pusillus and M. magnater were distributed in 7 Divisions; Yangon, Bago, Ayeyawady, Taninthayi, Magway, Mandalay and Sagaing Division, and 7 States; Mon, Kayin, Shan, Chin, Kayah, Kachin and Rakhine States of Myanmar.

  4. Antimicrobial resistence of Shigella species isolated during 2004 and 2005 from selected sites in Zimbabwe.

    Science.gov (United States)

    Ndlovu, N; Tarupiwa, A; Mudzori, J T

    2006-01-01

    To determine the predominant serotype and antibiotic sensitivity pattern of Shigella isolates during 2004 and 2005 in Zimbabwe. Cross sectional study. National Microbiology Reference Laboratory (NMRL), Harare, Zimbabwe. 259 clinical isolates of Shigella species isolated during 2004 and 2005 in Zimbabwe were studied. These samples had been referred to the NMRL for further testing. Serotype and antibiotic sensitivity pattern of Shigella species. Of the 259 clinical isolates of Shigella tested the following species were serotyped; 141 (54.4%) were S. flexneri; 70 (27%) S. sonnei; 38 (14.7%) S. dysenteriae and 10 (3.9%) S. boydii. About 4% of all Shigella isolates tested showed full sensitivity to commonly used antibiotics, 20.8% were resistant to one antibiotic only while 75.3% were resistant to at least two antibiotics. The most common resistance among Shigella species was to cotrimoxazole (89%), tetracycline (73%), ampicillin (49%) and chloramphenicol (41%). High susceptibility among Shigella species was observed to nalidixic acid (86%), ciprofloxacin (99%) and ceftazidine (99%). There was a low drug resistance of Shigella species to nalidixic acid, a drug of choice in Zimbabwe, except among Shigella dysenteriae type 1 strains. Continuous monitoring of the susceptibility patterns of Shigella species is important in order to detect the emergence of drug resistance and to update guidelines for antibiotic treatment in shigellosis.

  5. Analyzing fractal property of species abundance distribution and diversity indexes.

    Science.gov (United States)

    Su, Qiang

    2016-03-07

    Community diversity is usually characterized by numerical indexes; however it indeed depends on the species abundance distribution (SAD). Diversity indexes and SAD are based on the same information but treating as separate themes. Ranking species abundance from largest to smallest, the decreasing pattern can give the information about the SAD. Frontier proposed such SAD might be a fractal structure, and first applied the Zipf-Mandelbrot model to the SAD study. However, this model fails to include the Zipf model, and also fails to ensure an integer rank. In this study, a fractal model of SAD was reconstructed, and tested with 104 community samples from 8 taxonomic groups. The results show that there was a good fit of the presented model. Fractal parameter (p) determines the SAD of a community. The ecological significance of p relates to the "dominance" of a community. The correlation between p and classical diversity indexes show that Shannon index decreases and Simpson index increases as p increases. The main purpose of this paper is not to compare with other SADs models; it simply provides a new interpretation of SAD model construction, and preliminarily integrates diversity indexes and SAD model into a broader perspective of community diversity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. On the statistical mechanics of species abundance distributions.

    Science.gov (United States)

    Bowler, Michael G; Kelly, Colleen K

    2012-09-01

    A central issue in ecology is that of the factors determining the relative abundance of species within a natural community. The proper application of the principles of statistical physics to species abundance distributions (SADs) shows that simple ecological properties could account for the near universal features observed. These properties are (i) a limit on the number of individuals in an ecological guild and (ii) per capita birth and death rates. They underpin the neutral theory of Hubbell (2001), the master equation approach of Volkov et al. (2003, 2005) and the idiosyncratic (extreme niche) theory of Pueyo et al. (2007); they result in an underlying log series SAD, regardless of neutral or niche dynamics. The success of statistical mechanics in this application implies that communities are in dynamic equilibrium and hence that niches must be flexible and that temporal fluctuations on all sorts of scales are likely to be important in community structure. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Effects of species biological traits and environmental heterogeneity on simulated tree species distribution shifts under climate change

    Science.gov (United States)

    Wen J. Wang; Hong S. He; Frank R. Thompson; Martin A. Spetich; Jacob S. Fraser

    2018-01-01

    Demographic processes (fecundity, dispersal, colonization, growth, and mortality) and their interactions with environmental changes are notwell represented in current climate-distribution models (e.g., niche and biophysical process models) and constitute a large uncertainty in projections of future tree species distribution shifts.We investigate how species biological...

  8. Integrating DNA-based data into bioassessments improves our understanding of species distributions and species habitat relationships

    Science.gov (United States)

    The integration of DNA-based identification methods into bioassessments could result in more accurate representations of species distributions and species-habitat relationships. DNA-based approaches may be particularly informative for tracking the distributions of rare and/or inv...

  9. New derivatives of salicylamides: Preparation and antimicrobial activity against various bacterial species.

    Science.gov (United States)

    Pauk, Karel; Zadražilová, Iveta; Imramovský, Aleš; Vinšová, Jarmila; Pokorná, Michaela; Masaříková, Martina; Cížek, Alois; Jampílek, Josef

    2013-11-01

    Three series of salicylanilides, esters of N-phenylsalicylamides and 2-hydroxy-N-[1-(2-hydroxyphenylamino)-1-oxoalkan-2-yl]benzamides, in total thirty target compounds were synthesized and characterized. The compounds were evaluated against seven bacterial and three mycobacterial strains. The antimicrobial activities of some compounds were comparable or higher than the standards ampicillin, ciprofloxacin or isoniazid. Derivatives 3f demonstrated high biological activity against Staphylococcus aureus (⩽0.03μmol/L), Mycobacterium marinum (⩽0.40μmol/L) and Mycobacterium kansasii (1.58μmol/L), 3g shows activity against Clostridium perfringens (⩽0.03μmol/L) and Bacillus cereus (0.09μmol/L), 3h against Pasteurella multocida (⩽0.03μmol/L) and M. kansasii (⩽0.43μmol/L), 3i against methicillin-resistant S. aureus and B. cereus (⩽0.03μmol/L). The structure-activity relationships are discussed for all the compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Antioxidative, Antiproliferative and Antimicrobial Activities of Phenolic Compounds from Three Myrcia Species

    Directory of Open Access Journals (Sweden)

    Catarina dos Santos

    2018-04-01

    Full Text Available Myrcia bella Cambess., Myrcia fallax (Rich. DC. and Myrcia guianensis (Aubl. DC. (Myrtaceae are trees found in Brazilian Cerrado. They have been widely used in folk medicine for the treatment of gastrointestinal disorders, hemorrhagic and infectious diseases. Few reports have been found in the literature connecting their phenolic composition and biological activities. In this regard, we have profiled the main phenolic constituents of Myrcia spp. leaves extracts by ESI(−Q-TOF-MS. The main constituents found were ellagic acid (M. bella, galloyl glucose isomers (M. guianensis and hexahydroxydiphenic (HHDP acid derivatives (M. fallax. In addition, quercetin and myricetin derivatives were also found in all Myrcia spp. extracts. The most promising antioxidant activity, measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH scavenging activity, was found for M. fallax extracts (EC50 8.61 ± 0.22 µg·mL−1, being slightly less active than quercetin and gallic acid (EC50 2.96 ± 0.17 and 2.03 ± 0.02 µg·mL−1, respectively. For in vitro antiproliferative activity, M. guianensis showed good activity against leukemia (K562 TGI = 7.45 µg·mL−1. The best antimicrobial activity was observed for M. bella and M. fallax to Escherichia coli (300 and 250 µg·mL−1, respectively. In conclusion, the activities found are closely related to the phenolic composition of these plants.

  11. Prevalence and antimicrobial resistance of Listeria, Salmonella, and Yersinia species isolates in ducks and geese.

    Science.gov (United States)

    Jamali, Hossein; Radmehr, Behrad; Ismail, Salmah

    2014-04-01

    The aims of this study were to determine the prevalence and antimicrobial resistance of Listeria, Salmonella, and Yersinia spp. isolated from duck and goose intestinal contents. A total of 471 samples, including 291 duck and 180 goose intestinal contents, were purchased from wet markets between November 2008 and July 2010. Listeria, Salmonella, and Yersinia spp. were isolated from 58 (12.3%), 107 (22.7%), and 80 (17%) of the samples, respectively. It was concluded that Listeria ivanovii, Salmonella Thompson, and Yersinia enterocolitica were the predominant serovars among Listeria, Salmonella, and Yersinia spp., respectively. Moreover, resistance to tetracycline was common in Listeria (48.3%) and Salmonella spp. (63.6%), whereas 51.3% of the Yersinia spp. isolates were resistant to cephalothin. Therefore, continued surveillance of the prevalence of the pathogens and also of emerging antibiotic resistance is needed to render possible the recognition of foods that may represent risks and also ensure the effective treatment of listeriosis, salmonellosis, and yersiniosis.

  12. Comparison of antimicrobial susceptibilities of Corynebacterium species by broth microdilution and disk diffusion methods.

    Science.gov (United States)

    Weiss, K; Laverdière, M; Rivest, R

    1996-01-01

    Corynebacterium species are increasingly being implicated in foreign-body infections and in immunocompromised-host infections. However, there are no specific recommendations on the method or the criteria to use in order to determine the in vitro activities of the antibiotics commonly used to treat Corynebacterium infections. The first aim of our study was to compare the susceptibilities of various species of Corynebacterium to vancomycin, erythromycin, and penicillin by using a broth microdilution method and a disk diffusion method. Second, the activity of penicillin against our isolates was assessed by using the interpretative criteria recommended by the National Committee for Clinical Laboratory Standards for the determination of the susceptibility of streptococci and Listeria monocytogenes to penicillin. Overall, 100% of the isolates were susceptible to vancomycin, while considerable variations in the activities of erythromycin and penicillin were noted for the different species tested, including the non-Corynebacterium jeikeium species. A good correlation in the susceptibilities of vancomycin and erythromycin between the disk diffusion and the microdilution methods was observed. However, a 5% rate of major or very major errors was detected with the Listeria criteria, while a high rate of minor errors (18%) was noted when the streptococcus criteria were used. Our findings indicate considerable variations in the activities of erythromycin and penicillin against the various species of Corynebacterium. Because of the absence of definite recommendations, important discrepancies were observed between the methods and the interpretations of the penicillin activity. PMID:8849254

  13. Screening of the Enterocin-Encoding Genes and Antimicrobial Activity in Enterococcus Species.

    Science.gov (United States)

    Ogaki, Mayara Baptistucci; Rocha, Katia Real; Terra, MÁrcia Regina; Furlaneto, MÁrcia Cristina; Maia, Luciana Furlaneto

    2016-06-28

    In the current study, a total of 135 enterococci strains from different sources were screened for the presence of the enterocin-encoding genes entA, entP, entB, entL50A, and entL50B. The enterocin genes were present at different frequencies, with entA occurring the most frequently, followed by entP and entB; entL50A and L50B were not detected. The occurrence of single enterocin genes was higher than the occurrence of multiple enterocin gene combinations. The 80 isolates that harbor at least one enterocin-encoding gene (denoted "Gene(+) strains") were screened for antimicrobial activity. A total of 82.5% of the Gene(+) strains inhibited at least one of the indicator strains, and the isolates harboring multiple enterocin-encoding genes inhibited a larger number of indicator strains than isolates harboring a single gene. The indicator strains that exhibited growth inhibition included Listeria innocua strain CLIP 12612 (ATCC BAA-680), Listeria monocytogenes strain CDC 4555, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 29213, S. aureus ATCC 6538, Salmonella enteritidis ATCC 13076, Salmonella typhimurium strain UK-1 (ATCC 68169), and Escherichia coli BAC 49LT ETEC. Inhibition due to either bacteriophage lysis or cytolysin activity was excluded. The growth inhibition of antilisterial Gene+ strains was further tested under different culture conditions. Among the culture media formulations, the MRS agar medium supplemented with 2% (w/v) yeast extract was the best solidified medium for enterocin production. Our findings extend the current knowledge of enterocin-producing enterococci, which may have potential applications as biopreservatives in the food industry due to their capability of controlling food spoilage pathogens.

  14. Species delimitation of the Hyphydrus ovatus complex in western Palaearctic with an update of species distributions (Coleoptera, Dytiscidae

    Directory of Open Access Journals (Sweden)

    Johannes Bergsten

    2017-06-01

    Full Text Available The species status of Hyphydrus anatolicus Guignot, 1957 and H. sanctus Sharp, 1882, previously often confused with the widespread H. ovatus (Linnaeus, 1760, are tested with molecular and morphological characters. Cytochrome c oxidase subunit 1 (CO1 was sequenced for 32 specimens of all three species. Gene-trees were inferred with parsimony, time-free bayesian and strict clock bayesian analyses. The GMYC model was used to estimate species limits. All three species were reciprocally monophyletic with CO1 and highly supported. The GMYC species delimitation analysis unequivocally delimited the three species with no other than the three species solution included in the confidence interval. A likelihood ratio test rejected the one-species null model. Important morphological characters distinguishing the species are provided and illustrated. New distributional data are given for the following species: Hyphydrus anatolicus from Slovakia and Ukraine, and H. aubei Ganglbauer, 1891, and H. sanctus from Turkey.

  15. Distribution of the Ammoniated Species on the Surface of Ceres

    Science.gov (United States)

    Ammannito, E.; De Sanctis, M. C.; Carrorro, F. G.; Ciarniello, M.; Combe, J. P.; De Angelis, S.; Ehlmann, B. L.; Frigeri, A.; Marchi, S.; McSween, H. Y., Jr.; Raponi, A.; Toplis, M. J.; Tosi, F.; Castillo, J. C.; Capaccioni, F.; Capria, M. T.; Fonte, S.; Giardino, M.; Jaumann, R.; Longobardo, A.; Joy, S. P.; Magni, G.; McCord, T. B.; McFadden, L. A.; Palomba, E.; Pieters, C. M.; Polanskey, C. A.; Prettyman, T. H.; Rayman, M.; Raymond, C. A.; Schenk, P.; Zambon, F.; Russell, C. T.

    2016-12-01

    The Dawn spacecraft has been acquiring data on dwarf planet Ceres since January 2015 (1). The VIR spectrometer (0.25-5.0 μm) acquired data at different altitudes providing information on the composition of the surface of Ceres at resolutions ranging from few kilometers to about one hundred meters (2). The average spectrum of Ceres is well represented by a mixture of dark minerals, Mg- phyllosilicates, ammoniated clays, and Mg carbonates (3). This result confirms previous studies based on ground based spectra (4, 5). Maps of the surface at about 1 km/px show that the components identified in the average spectrum are present all across the surface with variations in their relative abundance (6). Some localized areas however have peculiar spectral characteristics. One example is the spectrum of the bright regions within Occator crater that is most consistent with a large amount of Na-carbonates and possibly ammonium salts (7). The presence of ammoniated species poses a constraint on the pH and redox condition during the evolution of Ceres. Therefore, we have studied the distribution across the surface of such species to better understand the evolutionary pathway of Ceres. References : (1) Russell, C. T. et al. 2016, Science. (2) De Sanctis M.C. et al., The VIR Spectrometer, 2011, Space Science Reviews. (3) De Sanctis M.C. et al. Ammoniated phyllosilicates on dwarf planet Ceres reveal an outer solar system origin, Nature, 2015. (4) King T. et al. (1992) Science, 255, 1551-1553. (5) Rivkin A.S. et al. (2006) Icarus, 185, 563-567. (6) Ammannito E. et al., Spectral diversity of Ceres surface as measured by VIR, 2016, Science. (7) De Sanctis et al. (2016), Nature

  16. Antimicrobial Effect of Copper Oxide Nanoparticles on Some Oral Bacteria and Candida Species

    Directory of Open Access Journals (Sweden)

    Amiri M

    2017-03-01

    Full Text Available Statement of Problem: Acid producing bacteria including Streptococcus mutans and lactobacilli cause tooth demineralization and lead to tooth decay. Also, oral colonization of the species of Candida has been reported in many studies that are resistant to antifungal agents. Objectives: In this study, antibacterial and antifungal effects of nano-CuO were studied against some oral bacteria and yeast fungi. Materials and Methods: The minimum inhibitory concentrations (MICs of copper oxide nanoparticles (CuO NPs for oral bacterial and fungal test strains were determined in 96-well microtiter plate technique. The agar diffusion test (ADT was employed to assess the antifungal properties of nystatin. Results: The MIC50 value of CuO NPs was determined at the range of 1–10 µg/ml for S. mutans, < 1 µg/ml for L. acidophilus, and 10 µg/ml for L. casei. Higher concentrations of CuO NPs (100-1000 µg/ml were effective on the bacterial cell growth, resulting in 100% reduction in the optical density in TSB medium. The cells of Candida albicans, C. krusei and C. glabrata were treated with CuO NPs and the results showed a decrease in fungal growth at a concentration of 1-1000 µg/ml in TSB medium. The MIC50 value of CuO NPs was determined 1000 µg/ml for three species of Candida. The diameter of growth inhibition zones of 1100 µg/ml nystatin was obtained 15-21 mm for clinical isolates of three species of Candida. Conclusions: With respect to the potential bactericidal activity of CuO NPs on various cariogenic bacteria examined in this study, these NPs could be introduce as a candidate control agent for preventing dental caries or dental infections. In our study, on the other hand, Nano copper oxide had a weak effect on the candida species.

  17. A simple model for skewed species-lifetime distributions

    KAUST Repository

    Murase, Yohsuke; Shimada, Takashi; Ito, Nobuyasu

    2010-01-01

    A simple model of a biological community assembly is studied. Communities are assembled by successive migrations and extinctions of species. In the model, species are interacting with each other. The intensity of the interaction between each pair

  18. Prevalence and antimicrobial susceptibility profile of listeria species from ready-to-eat foods of animal origin in Gondar Town, Ethiopia.

    Science.gov (United States)

    Garedew, Legesse; Taddese, Ayele; Biru, Tigist; Nigatu, Seleshe; Kebede, Elias; Ejo, Mebrat; Fikru, Abraham; Birhanu, Tamiru

    2015-05-12

    Listeriosis, mostly caused by Listeria monocytogenes species, has become a major concern to public health authorities due to its clinical severity and high mortality rate, particularly in high risk groups. Currently, there is limited information regarding the prevalence and antimicrobial susceptibility profiles of listeria species in ready-to-eat foods of animal origin in Gondar town, Ethiopia. The aim of this study was to determine the prevalence and antimicrobial susceptibility pattern of Listeria species isolated from ready-to-eat food of animal origin from public dinning places in Gondar town, Ethiopia. A cross sectional study on ready-toeat foods of animal origin sampled from major supermarkets, butcher shops, pastry shops, restaurants and hotels was carried out. Culture, biochemical and sugar tests were conducted for listeria species identification and disc diffusion test was performed to study the antimicrobial susceptibility profiles of the isolates. Out of 384 food samples examined, 96 (25%) were positive for Listeria species. Listeria monocytogenes was detected in 24 (6.25%) of the samples. Listeria monocytogenes was isolated from cake, raw meat, ice cream, minced beef, fish, unpasteurized milk and pizza in that order from higher to lower rate. Assessment of antimicrobial susceptibility profile of L. monocytogenes revealed the presence of four multi-drug resistant isolates. The higher resistance rate was recorded for penicillin, nalidixic acid, tetracycline and chloramphenicol, in decreasing order. All L. monocytogenes identified in the current study were sensitive to amoxicillin, cephalothin, cloxacillin, sulfamethoxazole, gentamicin and vancomycin. The presence of L. monocytogenes including drug resistant and multidrug resistant isolates in some ready-to-eat food items is an indicator of the presence of public health hazards to the consumer, particularly to the high-risk groups. Hence awareness creation on food safety and implementation of regulations

  19. Distribution patterns of rare earth elements in various plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wyttenbach, A.; Tobler, L.; Furrer, V. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs.

  20. Distribution patterns of rare earth elements in various plant species

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Tobler, L.; Furrer, V.

    1997-01-01

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs

  1. Two investigational glycylcyclines, DMG-DMDOT and DMG-MINO. Antimicrobial activity studies against gram-positive species.

    Science.gov (United States)

    Johnson, D M; Jones, R N

    1996-01-01

    DMG-DMDOT (CL-331,002 OR CL-331,928) and DMG-MINO (CL-329,998 or CL-344,677) are two new semisynthetic tetracyclines called glycylcyclines, with a broad spectrum of activity and includes Enterobacteriaceae, Gram-positive cocci, JK diphtheroids, and Bacillus cereus. Potent activity was demonstrated against all Streptococcus spp. strains [minimum inhibitory concentrations] (MIC90S) 0.06-0.25 micrograms/ml) and staphylococci (oxacillin susceptible ans resistant; MIC90S 0.12-2 micrograms/ml). Both glycylcyclines (MIC90, 0.06 micrograms/ml) were more potent than minocycline (MIC90 8 micrograms/ml) against Enterococcus faecium, many of which were vancomycin resistant (116 strains). Organisms with minocycline MICs at > or = 8 micrograms/ml (Staphylococcus aureus, enterococci, beta-hemolytic streptococci, and pneumococci) had glycylcycline MIC results ranging from 0.06 to 0.5 micrograms/ml (e.g., apparent use against existing tetracycline-resistance phenotypes). Drugs in this class appear promising for therapy of infections caused by Gram-positive species now testing resistant to contemporary antimicrobial agents, and further development of compounds in this class is encouraged.

  2. Antimicrobial susceptibility patterns, emm type distribution and genetic diversity of Streptococcus pyogenes recovered in Brazil

    Directory of Open Access Journals (Sweden)

    Glauber P Arêas

    2014-11-01

    Full Text Available Streptococcus pyogenes is responsible for a variety of infectious diseases and immunological complications. In this study, 91 isolates of S. pyogenes recovered from oropharynx secretions were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE analysis. All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance to erythromycin and clindamycin was 15.4%, which is higher than previous reports from this area, while 20.9% of the isolates were not susceptible to tetracycline. The macrolide resistance phenotypes were cMLSB (10 and iMLSB (4. The ermB gene was predominant, followed by the ermA gene. Thirty-two emm types and subtypes were found, but five (emm1, emm4, emm12, emm22, emm81 were detected in 48% of the isolates. Three new emm subtypes were identified (emm1.74, emm58.14, emm76.7. There was a strong association between emm type and PFGE clustering. A variety of PFGE profiles as well as emm types were found among tetracycline and erythromycin-resistant isolates, demonstrating that antimicrobial resistant strains do not result from the expansion of one or a few clones. This study provides epidemiological data that contribute to the development of suitable strategies for the prevention and treatment of such infections in a poorly studied area.

  3. Green Synthesis and Antimicrobial Activities of Silver Nanoparticles using Cell Free-Extracts of Enterococcus species

    Directory of Open Access Journals (Sweden)

    Iyabo C. OLADIPO

    2017-06-01

    Full Text Available Cell-free extracts of six strains of Enterococcus species obtained from fermented foods were used for the green synthesis of silver nanoparticles (AgNPs, which was characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR and transmission electron microscopy (TEM. The biosynthesized AgNPs were dark brown in colour having surface plasmon resonance in the range of 420-442 nm. The spherical shaped AgNPs had sizes of 4-55 nm, whose formations were facilitated by proteins as indicated by the presence of peaks 1,635-1,637 and 3,275-3,313 cm-1 in the FTIR spectra. The energy dispersive x-ray (EDX showed prominent presence of silver in the AgNPs colloidal solution, while the selected area electron diffraction was typified by the face-centred crystalline nature of silver. The particles inhibited the growth of multi-drug resistant clinical isolates of Escherichia coli, Klebsiella pneumoniae and Proteus vulgaris, and also potentiated the activities of ampicillin, ciprofloxacin and cefuroxime in the AgNPs-antibiotic synergy studies. In addition, the prospective relevance of the particles as nanopreservative in paints was demonstrated with the inhibition of growth of Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger and A. flavus in AgNPs-paint admixture. This report further demonstrates the green synthesis of AgNPs by strains of Enterococcus species.

  4. Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials

    Directory of Open Access Journals (Sweden)

    Yanke L Jay

    2011-04-01

    Full Text Available Abstract Background Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR in subpopulations of intestinal microflora including Escherichia coli. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in E. coli as an indicator bacterium. E. coli isolates (n = 531 were recovered from 140 cattle that were housed (10 animals/pen in 14 pens and received no dietary antimicrobials (control - 5 pens, CON, or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T, chlortetracycline + sulfamethazine (4 pens-TS, or virginiamycin (5 pens-V for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle. Results Overall, patterns of antimicrobial resistance expressed by E. coli isolates did not change among diet groups (CON vs. antibiotic treatments, however; isolates obtained on selective plates (i.e., MA,MT, exhibited multi-resistance to sulfamethoxazole and chloramphenicol more frequently when obtained from TS-fed steers than from other treatments. Antibiograms and PFGE patterns suggested that AMR E. coli were readily transferred among steers within pens. Most MT isolates possessed the tet(B efflux gene (58.2, 53.5, 40.8, and 50.6% of isolates from CON, T, TS, and V steers, respectively whereas among the MA (ampicillin-resistant isolates, the tem1-like determinant was predominant (occurring in 50, 66

  5. Antimicrobial Nisin Acts Against Saliva Derived Multi-Species Biofilms without Cytotoxicity to Human Oral Cells

    Directory of Open Access Journals (Sweden)

    Yvonne Lorraine Kapila

    2015-06-01

    Full Text Available Objectives: Nisin is a lantibiotic widely used for the preservation of food and beverages. Recently, investigators have reported that nisin may have clinical applications for treating bacterial infections. The aim of this study was to investigate the effects of ultra pure food grade Nisin ZP (> 95% purity on taxonomically diverse bacteria common to the human oral cavity and saliva derived multi-species oral biofilms, and to discern the toxicity of nisin against human cells relevant to the oral cavity. Methods: The MICs and MBCs of taxonomically distinct oral bacteria were determined using agar and broth dilution methods. To assess the effects of nisin on biofilms, two model systems were utilized: a static and a controlled flow microfluidic system. Biofilms were inoculated with pooled human saliva and fed filter-sterilized saliva for 20-22 h at 37°C. Nisin effects on cellular apoptosis and proliferation were evaluated using acridine orange/ethidium bromide fluorescent nuclear staining and lactate dehydrogenase activity assays. Results: Nisin inhibited planktonic growth of oral bacteria at low concentrations (2.5 – 50 μg/ml. Nisin also retarded development of multi-species biofilms at concentrations ≥ 1 μg/ml. Specifically, under biofilm model conditions, nisin interfered with biofilm development and reduced biofilm biomass and thickness in a dose-dependent manner. The treatment of pre-formed biofilms with nisin resulted in dose- and time-dependent disruption of the biofilm architecture along with decreased bacterial viability. Human cells relevant to the oral cavity were unaffected by the treatment of nisin at anti-biofilm concentrations and showed no signs of apoptotic changes unless treated with much higher concentrations (> 200 μg/ml. Conclusions: This work highlights the potential therapeutic value of high purity food grade nisin to inhibit the growth of oral bacteria and the development of biofilms relevant to oral diseases.

  6. Distribution Patterns of Ohio Stoneflies, with an Emphasis on Rare and Uncommon Species

    Science.gov (United States)

    Grubbs, Scott A.; Pessimo, Massimo; DeWalt, R. Edward

    2013-01-01

    Presently, 102 stonefly species (Plecoptera) have been reported from Ohio. All 9 Nearctic families are represented. Over 90% of the fauna exhibit a combination of broad Nearctic-widespread, eastern Nearctic-widespread, Appalachian, and eastern Nearctic-unglaciated distributions. In contrast, only 2 species display a central Nearctic-Prairie distribution. Seven species of Perlidae are likely no longer present (Acroneuria evoluta Klapálek, A. perplexa Frison, Attaneuria ruralis (Hagen), and Neoperla mainensis Banks) or have experienced marked range reductions (Acroneuria abnormis (Newman), A. frisoni Stark and Brown, and A. filicis Frison). Another nearly 31% of the fauna (32 species) are rare, uncommon, or have highly-limited distributions within the state. Twelve of these species have Appalachian distributions, and an additional 8 have eastern Nearctic-unglaciated distributions. The distributional status for each of the 32 rare/uncommon species is discussed. PMID:24219390

  7. New distribution records for four mammal species, with notes on their taxonomy and ecology

    Directory of Open Access Journals (Sweden)

    G.N. Bronner

    1990-09-01

    Full Text Available New distribution records for four small mammal species (Georychus capensis, Galerella pulverulenta, Rhinolophus swinnyi and Amblysomus julianae are presented, along with relevant notes on the taxonomy, karyology and ecology of these species.

  8. Species composition, abundance and distribution of hydromedusae from Dharamtar estuarine system, adjoining Bombay Harbour

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Tiwari, L.R.; Nair, V.R.

    Species composition, abundance and distribution of hydromedusae from Dharamtar estuarine system, adjoining Bombay Harbour, Maharashtra, India were investigated during 1984-1985. Twenty six species belonging to 19 genera were obtained from this area...

  9. Relating biomarkers to whole-organism effects using species sensitivity distributions : A pilot study for marine species exposed to oil

    NARCIS (Netherlands)

    Smit, M.G.D.; Bechmann, R.K.; Hendriks, A.J.; Skadsheim, A.; Larsen, B.K.; Baussant, T.; Bamber, S.; Sannei, S.

    2009-01-01

    Biomarkers are widely used to measure environmental impacts on marine species. For many biomarkers, it is not clear how the signal levels relate to effects on the whole organism. This paper shows how species sensitivity distributions (SSDs) can be applied to evaluate multiple biomarker responses in

  10. Determining the factors affecting the distribution of Muscari latifolium, an endemic plant of Turkey, and a mapping species distribution model.

    Science.gov (United States)

    Yilmaz, Hatice; Yilmaz, Osman Yalçın; Akyüz, Yaşar Feyza

    2017-02-01

    Species distribution modeling was used to determine factors among the large predictor candidate data set that affect the distribution of Muscari latifolium , an endemic bulbous plant species of Turkey, to quantify the relative importance of each factor and make a potential spatial distribution map of M. latifolium . Models were built using the Boosted Regression Trees method based on 35 presence and 70 absence records obtained through field sampling in the Gönen Dam watershed area of the Kazdağı Mountains in West Anatolia. Large candidate variables of monthly and seasonal climate, fine-scale land surface, and geologic and biotic variables were simplified using a BRT simplifying procedure. Analyses performed on these resources, direct and indirect variables showed that there were 14 main factors that influence the species' distribution. Five of the 14 most important variables influencing the distribution of the species are bedrock type, Quercus cerris density, precipitation during the wettest month, Pinus nigra density, and northness. These variables account for approximately 60% of the relative importance for determining the distribution of the species. Prediction performance was assessed by 10 random subsample data sets and gave a maximum the area under a receiver operating characteristic curve (AUC) value of 0.93 and an average AUC value of 0.8. This study provides a significant contribution to the knowledge of the habitat requirements and ecological characteristics of this species. The distribution of this species is explained by a combination of biotic and abiotic factors. Hence, using biotic interaction and fine-scale land surface variables in species distribution models improved the accuracy and precision of the model. The knowledge of the relationships between distribution patterns and environmental factors and biotic interaction of M. latifolium can help develop a management and conservation strategy for this species.

  11. Characterization and antimicrobial activity of silver nanoparticles, biosynthesized using Bacillus species

    Science.gov (United States)

    Ghiuță, I.; Cristea, D.; Croitoru, C.; Kost, J.; Wenkert, R.; Vyrides, I.; Anayiotos, A.; Munteanu, D.

    2018-04-01

    In this work, the biosynthesis of silver nanoparticles, using AgNO3 as a precursor, by two Bacillus species, namely Bacillus amyloliquefaciens and Bacillus subtillis, is reported. After the synthesis stages, the absorbance of the brown nanoparticle colloidal solutions was assessed by UV-vis spectrophotometry, which showed the peak absorbance values at 418 nm and 414 nm, corresponding to surface plasmon resonance of silver nanoparticles. The EDX, SEM and DLS analyses confirmed the formation of spherical silver nanoparticles with an average diameter smaller than 140 nm. XRD confirmed the presence of face-centered cubic silver crystals, with the highest intensity peak at 2θ = 38.12°, which corresponds to the (111) diffraction planes. The antibacterial activity after 24 h of incubation was observed against gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Salmonella, as well as gram positive: Staphylococcus aureus, Streptococcus pyogenes. Furthermore, the antifungal activity was assessed against Candida albicans. The inhibition zone was clearly observed on the plates containing silver nanoparticles, either standalone or in combination with antibiotics, thus showing their potentiating antibacterial effect.

  12. New record of the sympatric distribution of two Asian species of the horseshoe crab

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.

    distribution of two Asian species of the horses... http://www.ias.ac.in/currsci/sep25/articles14.htm 1 of 3 2/11/05 9:47 AM New record of the sympatric distribution of two Asian species of the horseshoe crab The geographical distribution of four extant species...... http://www.ias.ac.in/currsci/sep25/articles14.htm 2 of 3 2/11/05 9:47 AM This species was found breeding actively on relatively clean and sandy beaches. The other species (C. rotundicauda) was not reported in these areas.However, during the survey...

  13. Endangered Fish Species in Kansas: Historic vs Contemporary Distribution

    Science.gov (United States)

    Background/Question/Methods Kansas state has more freshwater fish species than other states in the west and northern US. Based on recent count, more than 140 fishes have been documented in Kansas rivers. And at least five are categorized as endangered species in Kansas (and thre...

  14. Iodine uptake and distribution in horticultural and fruit tree species

    Directory of Open Access Journals (Sweden)

    Alessandra Caffagni

    2012-07-01

    Full Text Available Iodine is an essential microelement for humans and iodine deficiency disorder (IDD is one of the most widespread nutrient-deficiency diseases in the world. Iodine biofortification of plants provides an attractive opportunity to increase iodine intake in humans and to prevent and control IDD. This study was conducted to investigate the iodine uptake and accumulation in edible portion of two fruit trees: plum and nectarine, and two horticultural crops: tomato and potato. Two type of iodine treatments (soil and foliar spray application, and, for fresh market tomato, two production systems (open field and greenhouse hydroponic culture were tested. The distribution of iodine in potato stem and leaves, and in plum tree fruits, leaves, and branches was investigated. Iodine content of potato tubers after postharvest storage and processing (cooking, and iodine content of nectarine fruits after postharvest storage and processing (peeling were also determined. Differences in iodine accumulation were observed among the four crops, between applications, and between production systems. In open field, the maximum iodine content ranged from 9.5 and 14.3 μg 100 g−1 for plum and nectarine fruit, to 89.4 and 144.0 μg 100 g−1 for potato tuber and tomato fruit, respectively. These results showed that nectarine and plum tree accumulated significantly lower amounts of iodine in their edible tissues, in comparison with potato and tomato. The experiments also indicated hydroponic culture as the most efficient system for iodine uptake in tomato, since its fresh fruits accumulated up to 2423 μg 100 g−1 of iodine. Iodine was stored mainly in the leaves, in all species investigated. Only a small portion of iodine was moved to plum tree branches and fruits, and to potato stems and tubers. No differences in iodine content after fruit peeling was observed. A significant increase in iodine content of potato was observed after baking, whereas a significant decrease was

  15. Thematic and spatial resolutions affect model-based predictions of tree species distribution.

    Science.gov (United States)

    Liang, Yu; He, Hong S; Fraser, Jacob S; Wu, ZhiWei

    2013-01-01

    Subjective decisions of thematic and spatial resolutions in characterizing environmental heterogeneity may affect the characterizations of spatial pattern and the simulation of occurrence and rate of ecological processes, and in turn, model-based tree species distribution. Thus, this study quantified the importance of thematic and spatial resolutions, and their interaction in predictions of tree species distribution (quantified by species abundance). We investigated how model-predicted species abundances changed and whether tree species with different ecological traits (e.g., seed dispersal distance, competitive capacity) had different responses to varying thematic and spatial resolutions. We used the LANDIS forest landscape model to predict tree species distribution at the landscape scale and designed a series of scenarios with different thematic (different numbers of land types) and spatial resolutions combinations, and then statistically examined the differences of species abundance among these scenarios. Results showed that both thematic and spatial resolutions affected model-based predictions of species distribution, but thematic resolution had a greater effect. Species ecological traits affected the predictions. For species with moderate dispersal distance and relatively abundant seed sources, predicted abundance increased as thematic resolution increased. However, for species with long seeding distance or high shade tolerance, thematic resolution had an inverse effect on predicted abundance. When seed sources and dispersal distance were not limiting, the predicted species abundance increased with spatial resolution and vice versa. Results from this study may provide insights into the choice of thematic and spatial resolutions for model-based predictions of tree species distribution.

  16. Two new species of Ateuchus with remarks on ecology, distributions, and evolutionary relationships (Coleoptera, Scarabaeidae, Scarabaeinae).

    Science.gov (United States)

    Moctezuma, Victor; Sánchez-Huerta, José Luis; Halffter, Gonzalo

    2018-01-01

    Two new species of the genus Ateuchus Weber are described from the region of Los Chimalapas, Oaxaca, Mexico: A. benitojuarezi sp. n. and A. colossus sp. n. A diagnosis for distinguishing these new species from the other species of this genus in North America is included. This paper is illustrated with pictures of the dorsal habitus and the male genitalia of the new species. The evolutionary relationships of the species are discussed, as well as their distribution and ecology. It is considered that the species of the genus Ateuchus present in North and Central America correspond to the Typical Neotropical and Mountain Mesoamerican distribution patterns.

  17. Past, present and future distributions of an Iberian Endemic, Lepus granatensis: ecological and evolutionary clues from species distribution models.

    Directory of Open Access Journals (Sweden)

    Pelayo Acevedo

    Full Text Available The application of species distribution models (SDMs in ecology and conservation biology is increasing and assuming an important role, mainly because they can be used to hindcast past and predict current and future species distributions. However, the accuracy of SDMs depends on the quality of the data and on appropriate theoretical frameworks. In this study, comprehensive data on the current distribution of the Iberian hare (Lepus granatensis were used to i determine the species' ecogeographical constraints, ii hindcast a climatic model for the last glacial maximum (LGM, relating it to inferences derived from molecular studies, and iii calibrate a model to assess the species future distribution trends (up to 2080. Our results showed that the climatic factor (in its pure effect and when it is combined with the land-cover factor is the most important descriptor of the current distribution of the Iberian hare. In addition, the model's output was a reliable index of the local probability of species occurrence, which is a valuable tool to guide species management decisions and conservation planning. Climatic potential obtained for the LGM was combined with molecular data and the results suggest that several glacial refugia may have existed for the species within the major Iberian refugium. Finally, a high probability of occurrence of the Iberian hare in the current species range and a northward expansion were predicted for future. Given its current environmental envelope and evolutionary history, we discuss the macroecology of the Iberian hare and its sensitivity to climate change.

  18. Past, present and future distributions of an Iberian Endemic, Lepus granatensis: ecological and evolutionary clues from species distribution models.

    Science.gov (United States)

    Acevedo, Pelayo; Melo-Ferreira, José; Real, Raimundo; Alves, Paulo Célio

    2012-01-01

    The application of species distribution models (SDMs) in ecology and conservation biology is increasing and assuming an important role, mainly because they can be used to hindcast past and predict current and future species distributions. However, the accuracy of SDMs depends on the quality of the data and on appropriate theoretical frameworks. In this study, comprehensive data on the current distribution of the Iberian hare (Lepus granatensis) were used to i) determine the species' ecogeographical constraints, ii) hindcast a climatic model for the last glacial maximum (LGM), relating it to inferences derived from molecular studies, and iii) calibrate a model to assess the species future distribution trends (up to 2080). Our results showed that the climatic factor (in its pure effect and when it is combined with the land-cover factor) is the most important descriptor of the current distribution of the Iberian hare. In addition, the model's output was a reliable index of the local probability of species occurrence, which is a valuable tool to guide species management decisions and conservation planning. Climatic potential obtained for the LGM was combined with molecular data and the results suggest that several glacial refugia may have existed for the species within the major Iberian refugium. Finally, a high probability of occurrence of the Iberian hare in the current species range and a northward expansion were predicted for future. Given its current environmental envelope and evolutionary history, we discuss the macroecology of the Iberian hare and its sensitivity to climate change.

  19. hookworm species distribution around asendabo town jimma zone

    African Journals Online (AJOL)

    DigLab

    acknowledged cause of anemia as a result of intestinal blood loss. The aim of this study was to ... KEY WORDS: Hookworm species, anemia, helminth, Asendabo, Jimma, Ethiopia. ... nematode parasites Necator americanus and Ancylostoma.

  20. Studies on antimicrobial activity and brine shrimp lethality of crude samples of six different species of puffer fishes

    Directory of Open Access Journals (Sweden)

    Masilamani Mohan Raj

    2015-07-01

    Full Text Available Objective: To evaluate the antimicrobial activity and brine shrimp lethality activity of six different species of puffer fishes, including Cyclichthys orbicularis, Diodon holocanthus, Canthigaster solandri, Arthron hispidus, A. inermis and Lagocephalua inermis (L. inermis. Methodology: The puffer fishes were collected from Annangkovil Fish Landing Centre (Lattitude 11°30.47' N; Longitude 79°47.02' E, Parangipettai, Southeast Coast of India during summer season because of availability. Fresh tissue samples were collected from the clearly washed specimens, extracted with methanol at 37 °C for 3 days and filtered through Whatman No. 1 filter paper. The solvents such as methanol and ethanol were concentrated by using rotary evaporator under reduced pressure. The dark brown gummy mass was stored at 4 °C for further analysis. Prepared crude samples were analysed with human pathogens to assess the antibacterial activity and this was carried out by using standard disc diffusion method. The brine shrimp lethality was calculated as the percentage of mortality which was firstly calculated by dividing the number of dead larvae by the total number and then multiplied to 100%. Results: The antibacterial activity of crude extract of puffer fishes were exhibited against 10 different human bacterial pathogens. Among the ten human pathogens, Arthron hispidus showed maximum zone of inhibition (8 mm against Staphylococcus aureus while L. inermis showed minimum activity (1 mm against Proteus mirabilis and no zone of inhibition was observed against Staphylococcus aureus. Brine shrimp lethality was examined with six puffer fish extracts. Cyclichthys orbicularis showed maximum mortalities as 100% and L. inermis showed minimum mortalities as 70% at a concentration of 500 µg/mL. Conclusion: In conclusion, the study showed the preliminary investigation of crude extracts of puffer fishes about the prominent activity against human bacterial pathogens. The extracts had

  1. Temperature affects species distribution in symbiotic populations of Vibrio spp.

    Science.gov (United States)

    Nishiguchi, M K

    2000-08-01

    The genus Sepiola (Cephalopoda: Sepiolidae) contains 10 known species that occur in the Mediterranean Sea today. All Sepiola species have a light organ that contains at least one of two species of luminous bacteria, Vibrio fischeri and Vibrio logei. The two Vibrio species coexist in at least four Sepiola species (S. affinis, S. intermedia, S. ligulata, and S. robusta), and their concentrations in the light organ depend on changes in certain abiotic factors, including temperature. Strains of V. fischeri grew faster in vitro and in Sepiola juveniles when they were incubated at 26 degrees C. In contrast, strains of V. logei grew faster at 18 degrees C in culture and in Sepiola juveniles. When aposymbiotic S. affinis or S. ligulata juveniles were inoculated with one Vibrio species, all strains of V. fischeri and V. logei were capable of infecting both squid species at the optimum growth temperatures, regardless of the squid host from which the bacteria were initially isolated. However, when two different strains of V. fischeri and V. logei were placed in direct competition with each other at either 18 or 26 degrees C, strains of V. fischeri were present in sepiolid light organs in greater concentrations at 26 degrees C, whereas strains of V. logei were present in greater concentrations at 18 degrees C. In addition to the competition experiments, the ratios of the two bacterial species in adult Sepiola specimens caught throughout the season at various depths differed, and these differences were correlated with the temperature in the surrounding environment. My findings contribute additional data concerning the ecological and environmental factors that affect host-symbiont recognition and may provide insight into the evolution of animal-bacterium specificity.

  2. Protectiveness of Species Sensitivity Distribution Hazard Concentrations for Acute Toxicity Used in Endangered Species Risk Assessment

    Science.gov (United States)

    A primary objective of threatened and endangered species conservation is to ensure that chemical contaminants and other stressors do not adversely affect listed species. Assessments of the ecological risks of chemical exposures to listed species often rely on the use of surrogate...

  3. Distribution and content of ellagitannins in Finnish plant species.

    Science.gov (United States)

    Moilanen, Johanna; Koskinen, Piia; Salminen, Juha-Pekka

    2015-08-01

    The results of a screening study, in which a total of 82 Finnish plant species were studied for their ellagitannin composition and content, are presented. The total ellagitannin content was determined by HPLC-DAD, the detected ellagitannins were further characterized by HPLC-ESI-QTOF-MS and divided into four structurally different sub-groups. Thirty plant species were found to contain ellagitannins and the ellagitannin content in the crude extracts varied from few mgg(-1) to over a hundred mgg(-1). Plant families that were rich in ellagitannins (>90mgg(-1) of the crude extract) were Onagraceae, Lyhtraceae, Geraniaceae, Elaeagnaceae, Fagaceae and some species from Rosaceae. Plant species that contained moderate amounts of ellagitannins (31-89mgg(-1) of the crude extract) were representatives of the family Rosaceae. Plant species that contained low amounts of ellagitannins (1-30mgg(-1) of the crude extract) were representatives of the families Betulaceae and Myricaceae. The specific ellagitannin composition of the species allowed their chemotaxonomic classification and the comparison between the older Cronquist's classification and the nowadays preferred Angiosperm Phylogeny Group classification. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Directory of Open Access Journals (Sweden)

    Hyeyeong Choe

    Full Text Available Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the

  5. Validation of the Explorer® 2.0 test coupled to e-Reader® for the screening of antimicrobials in muscle from different animal species.

    Science.gov (United States)

    Mata, Luis; Sanz, David; Razquin, Pedro

    2014-01-01

    The Explorer(®) 2.0 tube test is a microbial inhibition test for the screening of antimicrobial residues in food samples. The new e-Reader(®) device coupled to Explorer(®) 2.0 operates by incubation at a selected temperature, determination of the endpoint of the assay and interpretation to generate results. This system was validated for muscle samples according to the European Commission Decision 2002/657/EC. Sensitivity towards 25 substances from several groups of antimicrobials was investigated in a first step. Detection capabilities for six substances representing the six major antimicrobial groups were also determined in bovine muscle. The detection capabilities for amoxicillin (10 µg l(-1)), cefalexin (200 µg l(-1)), doxycyclin (100 µg l(-1)), sulfamethazine (100 µg l(-1)), tylosin (100 µg l(-1)) and neomycin (200 µg l(-1)) were in all cases at or below the maximum residue limit (MRL). Specificity and applicability of the test were demonstrated with muscle samples from four animal species (bovine, porcine, ovine and poultry) and results were found to be satisfactory. Ruggedness was evaluated on negative and spiked samples with sulfamethazine as a representative antimicrobial. Neither false-positives nor false-negatives were detected when varying the sample volume, the time of pre-incubation, the temperature of incubation and the batch of the test. These results prove that Explorer(®) 2.0 coupled to e-Reader(®) is a valuable tool for the screening of a broad range of antimicrobials in muscle. This new methodology simplifies the analysis and increases the accuracy of interpretation of the test results since the endpoint of the assay is automatically determined and results are interpreted objectively.

  6. Factors influencing non-native tree species distribution in urban landscapes

    Science.gov (United States)

    Wayne C. Zipperer

    2010-01-01

    Non-native species are presumed to be pervasive across the urban landscape. Yet, we actually know very little about their actual distribution. For this study, vegetation plot data from Syracuse, NY and Baltimore, MD were used to examine non-native tree species distribution in urban landscapes. Data were collected from remnant and emergent forest patches on upland sites...

  7. Current state of the art for statistical modeling of species distributions [Chapter 16

    Science.gov (United States)

    Troy M. Hegel; Samuel A. Cushman; Jeffrey Evans; Falk Huettmann

    2010-01-01

    Over the past decade the number of statistical modelling tools available to ecologists to model species' distributions has increased at a rapid pace (e.g. Elith et al. 2006; Austin 2007), as have the number of species distribution models (SDM) published in the literature (e.g. Scott et al. 2002). Ten years ago, basic logistic regression (Hosmer and Lemeshow 2000)...

  8. Identifying the rooted species tree from the distribution of unrooted gene trees under the coalescent.

    Science.gov (United States)

    Allman, Elizabeth S; Degnan, James H; Rhodes, John A

    2011-06-01

    Gene trees are evolutionary trees representing the ancestry of genes sampled from multiple populations. Species trees represent populations of individuals-each with many genes-splitting into new populations or species. The coalescent process, which models ancestry of gene copies within populations, is often used to model the probability distribution of gene trees given a fixed species tree. This multispecies coalescent model provides a framework for phylogeneticists to infer species trees from gene trees using maximum likelihood or Bayesian approaches. Because the coalescent models a branching process over time, all trees are typically assumed to be rooted in this setting. Often, however, gene trees inferred by traditional phylogenetic methods are unrooted. We investigate probabilities of unrooted gene trees under the multispecies coalescent model. We show that when there are four species with one gene sampled per species, the distribution of unrooted gene tree topologies identifies the unrooted species tree topology and some, but not all, information in the species tree edges (branch lengths). The location of the root on the species tree is not identifiable in this situation. However, for 5 or more species with one gene sampled per species, we show that the distribution of unrooted gene tree topologies identifies the rooted species tree topology and all its internal branch lengths. The length of any pendant branch leading to a leaf of the species tree is also identifiable for any species from which more than one gene is sampled.

  9. Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California

    Science.gov (United States)

    Franklin, J.; Wejnert, K.E.; Hathaway, S.A.; Rochester, C.J.; Fisher, R.N.

    2009-01-01

    Aim: Several studies have found that more accurate predictive models of species' occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the data used to train the model. We examined the effect of model type, species rarity class, species' survey frequency, detectability and manipulated sample prevalence on the accuracy of distribution models developed for 30 reptile and amphibian species. Location: Coastal southern California, USA. Methods: Classification trees, generalized additive models and generalized linear models were developed using species presence and absence data from 420 locations. Model performance was measured using sensitivity, specificity and the area under the curve (AUC) of the receiver-operating characteristic (ROC) plot based on twofold cross-validation, or on bootstrapping. Predictors included climate, terrain, soil and vegetation variables. Species were assigned to rarity classes by experts. The data were sampled to generate subsets with varying ratios of presences and absences to test for the effect of sample prevalence. Join count statistics were used to characterize spatial dependence in the prediction errors. Results: Species in classes with higher rarity were more accurately predicted than common species, and this effect was independent of sample prevalence. Although positive spatial autocorrelation remained in the prediction errors, it was weaker than was observed in the species occurrence data. The differences in accuracy among model types were slight. Main conclusions: Using a variety of modelling methods, more accurate species distribution models were developed for rarer than for more common species. This was presumably because it is difficult to discriminate suitable from unsuitable habitat for habitat generalists, and not as an artefact of the

  10. In vitro antimicrobial susceptibility in clinical isolates of Enterococcus species Susceptibilidad antimicrobiana in vitro en aislamientos clínicos de Enterococcus species

    Directory of Open Access Journals (Sweden)

    Ernesto Calderón-Jaimes

    2003-04-01

    Full Text Available OBJECTIVE: To describe the antimicrobial activity of several antimicrobial agents against 97 clinical significant isolates of Enterococcus spp. MATHERIAL AND METHODS: During a 2-year prospective study at Instituto Nacional de Pediatria (National Institute of Pediatrics in Mexico City. Ninety seven strains of Enterococcus spp. (60 E. faecalis and 37 E. faecium were tested against 11 antibiotics. Susceptibility tests were performed with agar, according to the standards of the sNational Committee for Clinical Laboratory Standards (NCCLS. Isolates were screened for high-level resistance (HLR to beta-lactams, aminoglycosides, glycopeptides and other antibiotics, as well as for vancomycin-phenotypes. Differences between proportions were evaluated with chi2 of Fisher exact fest. RESULTS: Overall resistance rates to the antibiotics tested were: 17/97 (17.5% to penicillin, ampicillin, amoxicillin-clavulanate and imipenem. There was neither HLR nor beta-lactamase production; 74/97 (48.4% were resistant to erythromycin; 60% to ciprofloxacin; 31/97 (32% to gentamicin, and 55/97 (56.7% to streptomycin. Seven strains were vancomycin-resistant enterococci (VRE, all of them identified as E. faecium; 5/7 with Van A and 2/7 with Van B phenotypes. All the isolates were susceptible to linezolid. The difference in susceptibility among species was significant. CONCLUSIONS: Mutidrug-resistant enterococci is a real problem and continuous surveillance is necessary. The microbiology laboratory is the first line of defense against the spread of multiantibiotic-resistan enterococci in the hospital environment . All the strains recovered should be tested for susceptibility to ampicillin, streptomycin, gentamicin and glycopeptides.OBJECTIVO: Describir la actividad antimicrobiana de varios antibióticos, contra 97 cepas de Enterococcus spp., consideradas como aislamientos clínicamente significativos. MATERIAL Y MÉTODOS: En un estudio prospectivo de dos años, (enero de 1998

  11. Biotic and abiotic variables show little redundancy in explaining tree species distributions

    DEFF Research Database (Denmark)

    Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.

    2010-01-01

    Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...

  12. Species abundance distributions : moving beyond single prediction theories to integration within an ecological framework

    NARCIS (Netherlands)

    McGill, Brian J.; Etienne, Rampal S.; Gray, John S.; Alonso, David; Anderson, Marti J.; Benecha, Habtamu Kassa; Dornelas, Maria; Enquist, Brian J.; Green, Jessica L.; He, Fangliang; Hurlbert, Allen H.; Magurran, Anne E.; Marquet, Pablo A.; Maurer, Brian A.; Ostling, Annette; Soykan, Candan U.; Ugland, Karl I.; White, Ethan P.

    2007-01-01

    Species abundance distributions (SADs) follow one of ecology's oldest and most universal laws - every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the

  13. Species abundance distributions: moving beyond single prediction theories to integration within an ecological framework

    NARCIS (Netherlands)

    McGill, B.J.; Etienne, R.S.; Gray, J.S.; Alonso, D.; Anderson, M.J.; Benecha, H.K.

    2007-01-01

    Species abundance distributions (SADs) follow one of ecology's oldest and most universal laws ¿ every community shows a hollow curve or hyperbolic shape on a histogram with many rare species and just a few common species. Here, we review theoretical, empirical and statistical developments in the

  14. Modelling the potential spatial distribution of mosquito species using three different techniques

    NARCIS (Netherlands)

    Cianci, D.; Hartemink, N.; Ibáñez-Justicia, A.

    2015-01-01

    Background: Models for the spatial distribution of vector species are important tools in the assessment of the risk of establishment and subsequent spread of vector-borne diseases. The aims of this study are to define the environmental conditions suitable for several mosquito species through species

  15. Eco-taxonomic distribution of plant species around motor mechanic ...

    African Journals Online (AJOL)

    A survey of plant species and their families present in auto mechanic workshops in Benin City and Asaba was carried out. The frequency of occurrence of plants in the sites visited was used to determine prevalence. Peperomia pellucida occurred most in all the sites visited with a 55% frequency. The high rate of occurrence ...

  16. Alien fish species in upper Sakarya River and their distribution ...

    African Journals Online (AJOL)

    However, the fact that the flood plains have been reclaimed, excessive hunting, destruction of the ecologic balance and invasion of the area by the alien fish species threatens the fish stocks in Sakarya River. In this study, we aimed to determine the dispersion area of Carassius gibelio (Bloch, 1782), Oreochromis niloticus ...

  17. Distribution and diversity of mangrove species in Gokana Local ...

    African Journals Online (AJOL)

    Plots 1 and 2 were dominated by Rhizophora racemosa (62.07% and 41.17% respectively). Plots 3 were dominated by R. mangle (4 1.67%) while Plots 4 had 26.56% of Acrostichum aureum and 26.56% of Phoenix reclinata. The overlapping mangrove species occurrence (Laguncularia racemosa and R. mangle) at the ...

  18. fish species and size distribution and abundance in different areas

    African Journals Online (AJOL)

    Larger individuals dominated in deep waters recording a mode at 45.5 cm TL. ... as a result of trophic interactions with introduced species ... sea level. The climate is equatorial with two wet seasons, one between October and. December, the ...

  19. The distribution, composition and abundance of fish species in two ...

    African Journals Online (AJOL)

    Fish composition and abundance of two Gold mine reservoir were investigated between May, 2008 and May, 2009. Seven fish families comprising of twelve species of fish were caught during the period of study. The families of fish caught included Anabantidae, Channidae, Clariidae, Cichlidae, Melanopluridae, Mormyridae ...

  20. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@uts.edu.a [School of Applied Sciences, RMIT University, Victoria (Australia); Centre for Environmental Sustainability, Department of Environmental Science, University of Technology Sydney, New South Wales (Australia); Marchant, Richard [Department of Entomology, Museum of Victoria, Victoria (Australia); Schaefer, Ralf B. [School of Applied Sciences, RMIT University, Victoria (Australia); Metzeling, Leon [EPA Victoria, Macleod, Victoria (Australia); Dunlop, Jason E. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Queensland (Australia); Choy, Satish C. [Department of Environment and Resource Management, Indooroopilly, Queensland (Australia); Goonan, Peter [South Australia Environment Protection Authority, Adelaide, South Australia (Australia)

    2011-01-15

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC{sub p} value). However, at the PC{sub p} value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r{sup 2} {>=} 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  1. The definition of species richness used by species sensitivity distributions approximates observed effects of salinity on stream macroinvertebrates

    International Nuclear Information System (INIS)

    Kefford, Ben J.; Marchant, Richard; Schaefer, Ralf B.; Metzeling, Leon; Dunlop, Jason E.; Choy, Satish C.; Goonan, Peter

    2011-01-01

    The risk of chemicals for ecological communities is often forecast with species sensitivity distributions (SSDs) which are used to predict the concentration which will protect p% of species (PC p value). However, at the PC p value, species richness in nature would not necessary be p% less than at uncontaminated sites. The definition of species richness inherent to SSDs (contaminant category richness) contrasts with species richness typically measured in most field studies (point richness). We determine, for salinity in eastern Australia, whether these definitions of stream macroinvertebrate species richness are commensurable. There were strong relationships (r 2 ≥ 0.87) between mean point species, family and Ephemeroptera, Trichoptera and Plecoptera species richness and their respective contamination category richness. Despite differences in the definition of richness used by SSDs and field biomonitoring, their results in terms of relative species loss from salinity in south-east Australia are similar. We conclude that in our system both definitions are commensurable. - Definitions of species richness inherit in SSDs and biomonitoring are for salinity in south-east Australia commensurable.

  2. Aquatic dance flies (Diptera, Empididae, Clinocerinae and Hemerodromiinae of Greece: species richness, distribution and description of five new species

    Directory of Open Access Journals (Sweden)

    Marija Ivković

    2017-12-01

    Full Text Available All records of aquatic dance flies (37 species in subfamily Clinocerinae and 10 species in subfamily Hemerodromiinae from the territory of Greece are summarized, including previously unpublished data and data on five newly described species (Chelifera horvati Ivković & Sinclair, sp. n., Wiedemannia iphigeniae Ivković & Sinclair, sp. n., W. ljerkae Ivković & Sinclair, sp. n., W. nebulosa Ivković & Sinclair, sp. n. and W. pseudoberthelemyi Ivković & Sinclair, sp. n.. The new species are described and illustrated, the male terminalia of Clinocera megalatlantica (Vaillant are illustrated and the distributions of all species within Greece are listed. The aquatic Empididae fauna of Greece consists of 47 species, with the following described species reported for the first time: Chelifera angusta Collin, Hemerodromia melangyna Collin, Clinocera megalatlantica, Kowarzia plectrum (Mik, Phaeobalia dimidiata (Loew, W. (Chamaedipsia beckeri (Mik, W. (Philolutra angelieri Vaillant and W. (P. chvali Joost. A key to species of aquatic Empididae of Greece is provided for the first time. Information related to the European Ecoregions in which species were found is given. Compared to the other studied countries in the Balkans, the Greek species assemblage is most similar to that of the Former Yugoslav Republic of Macedonia.

  3. The role of demography, intra-species variation, and species distribution models in species’ projections under climate change

    DEFF Research Database (Denmark)

    Swab, Rebecca Marie; Regan, Helen M.; Matthies, Diethart

    2015-01-01

    Organisms are projected to shift their distribution ranges under climate change. The typical way to assess range shifts is by species distribution models (SDMs), which predict species’ responses to climate based solely on projected climatic suitability. However, life history traits can impact...... species’ responses to shifting habitat suitability. Additionally, it remains unclear if differences in vital rates across populations within a species can offset or exacerbate the effects of predicted changes in climatic suitability on population viability. In order to obtain a fuller understanding...... of the response of one species to projected climatic changes, we coupled demographic processes with predicted changes in suitable habitat for the monocarpic thistle Carlina vulgaris across northern Europe. We first developed a life history model with species-specific average fecundity and survival rates...

  4. Multicenter study in Taiwan of the in vitro activities of nemonoxacin, tigecycline, doripenem, and other antimicrobial agents against clinical isolates of various Nocardia species.

    Science.gov (United States)

    Lai, Chih-Cheng; Liu, Wei-Lun; Ko, Wen-Chien; Chen, Yen-Hsu; Tan, Hon-Ren; Huang, Yu-Tsung; Hsueh, Po-Ren

    2011-05-01

    The aim of this study was to assess the in vitro activities of nemonoxacin (a novel nonfluorinated quinolone), doripenem, tigecycline, and 16 other antimicrobial agents against Nocardia species. The MICs of the 19 agents against 151 clinical isolates of Nocardia species were determined by the broth microdilution method. The isolates were identified to the species level using 16S rRNA gene sequencing analysis. The results showed that N. brasiliensis (n=60; 40%) was the most common species, followed by N. cyriacigeorgica (n=24; 16%), N. farcinica (n=12; 8%), N. beijingensis (n=9), N. otitidiscaviarum (n=8), N. nova (n=8), N. asiatica (n=7), N. puris (n=6), N. flavorosea (n=5), N. abscessus (n=3), N. carnea (2), and one each of N. alba, N. asteroides complex, N. rhamnosiphila, N. elegans, N. jinanensis, N. takedensis, and N. transvalensis. The MIC90s of the tested quinolones against the N. brasiliensis isolates were in the order nemonoxacin=gemifloxacinNocardia isolates. Among the four tested carbapenems, imipenem had the lowest MIC90s. All of the clinical isolates of N. beijingensis, N. otitidiscaviarum, N. nova, and N. puris and more than half of the N. brasiliensis and N. cyriacigeorgica isolates were resistant to at least one antimicrobial agent. The results of this in vitro study suggest that nemonoxacin, linezolid, and tigecycline are promising treatment options for nocardiosis. Further investigation of their clinical role is warranted.

  5. Antimicrobial potential of endophytic fungi derived from three seagrass species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii.

    Directory of Open Access Journals (Sweden)

    Preuttiporn Supaphon

    Full Text Available Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodoceaserrulata (Family Cymodoceaceae, Halophilaovalis and Thalassiahemprichii (Family Hydrocharitaceae were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporumgypseum and Penicilliummarneffei. Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C. serrulata, Trichoderma spp. PSU-ES8 and PSU-ES38 from H. ovalis, and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T. hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses.

  6. How much does climate change threaten European forest tree species distributions?

    Science.gov (United States)

    Dyderski, Marcin K; Paź, Sonia; Frelich, Lee E; Jagodziński, Andrzej M

    2018-03-01

    Although numerous species distribution models have been developed, most were based on insufficient distribution data or used older climate change scenarios. We aimed to quantify changes in projected ranges and threat level by the years 2061-2080, for 12 European forest tree species under three climate change scenarios. We combined tree distribution data from the Global Biodiversity Information Facility, EUFORGEN, and forest inventories, and we developed species distribution models using MaxEnt and 19 bioclimatic variables. Models were developed for three climate change scenarios-optimistic (RCP2.6), moderate (RCP4.5), and pessimistic (RPC8.5)-using three General Circulation Models, for the period 2061-2080. Our study revealed different responses of tree species to projected climate change. The species may be divided into three groups: "winners"-mostly late-successional species: Abies alba, Fagus sylvatica, Fraxinus excelsior, Quercus robur, and Quercus petraea; "losers"-mostly pioneer species: Betula pendula, Larix decidua, Picea abies, and Pinus sylvestris; and alien species-Pseudotsuga menziesii, Quercus rubra, and Robinia pseudoacacia, which may be also considered as "winners." Assuming limited migration, most of the species studied would face a significant decrease in suitable habitat area. The threat level was highest for species that currently have the northernmost distribution centers. Ecological consequences of the projected range contractions would be serious for both forest management and nature conservation. © 2017 John Wiley & Sons Ltd.

  7. High-resolution pattern of mangrove species distribution is controlled by surface elevation

    Science.gov (United States)

    Leong, Rick C.; Friess, Daniel A.; Crase, Beth; Lee, Wei Kit; Webb, Edward L.

    2018-03-01

    Mangrove vegetation species respond to multiple environmental gradients, and an enhanced understanding of how mangrove species are distributed across these gradients will facilitate conservation and management. Many environmental gradients correlate with tidal inundation; however small-scale inundation patterns resulting from microtopographical changes are difficult to capture empirically. In contrast, surface elevation is often a suitable, measurable and cost-effective proxy for inundation. This study investigated the relationships between species distribution and surface elevation in a mangrove forest in northwest Singapore. Through high-resolution land surveying, we developed a digital elevation model (DEM) and conducted a comprehensive survey of 4380 trees with a stem diameter ≥ 5 cm. A total of 15 species were encountered, and elevation envelopes were generated for 12. Species envelopes were distributed along an elevation continuum, with most species overlapping within the continuum. Spatial autocorrelation (SAC) was present for nine of the 15 species, and when taken into account, species ordering was modified across the elevation continuum. The presence of SAC strongly reinforces the need for research to control for SAC: classical spatial description of mangrove species distribution should be revised to account for ecological factors. This study suggests that (1) surface elevation applies strong controls on species distribution and (2) most mangroves at our study site have similar physiological tolerances.

  8. The Quercus feeding Stigmella species of the West Palaearctic: new species, key and distribution (Lepidoptera: Nepticulidae)

    NARCIS (Netherlands)

    Nieukerken, van E.J.; Johansson, R.

    2003-01-01

    The species of the Stigmella ruficapitella group occurring in the Western Palaearctic and feeding on Quercus are reviewed. We recognise 19 species, five of which are described as new: Stigmella fasciata sp. n. on Quercus pubescens from Slovenia, Croatia, Greece and Turkey, S. cocciferae sp. n. on Q.

  9. Distribution of particulate carbohydrate species in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.; Gopalakrishna, V.V.

    and the C/N ratios. Carbohydrate production by micro-organisms is influenced by phase of growth, nutrient status, phytoplankton species composition and/or bacte- rial activity (Morris 1981; D’Souza and Bhosle 2001). Phytoplankton composition varied spatially... Neutral monosaccharides from a hypersaline tropical environment: Applications to the characterization of modern and ancient ecosystems; Geochim. Cosmochim. Acta 57 3063–3071. Morris I 1981 Photosynthetic products, physiological state and phytoplankton...

  10. Distribution patterns of invasive alien species in Alabama, USA

    Directory of Open Access Journals (Sweden)

    Xiongwen Chen

    2012-12-01

    Full Text Available Invasive alien species (IAS cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge.Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance” have been proposedfrom numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergentpatterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensiveland use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and thenumber of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the abovethree hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications forstrategically managing local IAS are discussed.

  11. Separating the effects of environment and space on tree species distribution: from population to community.

    Science.gov (United States)

    Lin, Guojun; Stralberg, Diana; Gong, Guiquan; Huang, Zhongliang; Ye, Wanhui; Wu, Linfang

    2013-01-01

    Quantifying the relative contributions of environmental conditions and spatial factors to species distribution can help improve our understanding of the processes that drive diversity patterns. In this study, based on tree inventory, topography and soil data from a 20-ha stem-mapped permanent forest plot in Guangdong Province, China, we evaluated the influence of different ecological processes at different spatial scales using canonical redundancy analysis (RDA) at the community level and multiple linear regression at the species level. At the community level, the proportion of explained variation in species distribution increased with grid-cell sizes, primarily due to a monotonic increase in the explanatory power of environmental variables. At the species level, neither environmental nor spatial factors were important determinants of overstory species' distributions at small cell sizes. However, purely spatial variables explained most of the variation in the distributions of understory species at fine and intermediate cell sizes. Midstory species showed patterns that were intermediate between those of overstory and understory species. At the 20-m cell size, the influence of spatial factors was stronger for more dispersal-limited species, suggesting that much of the spatial structuring in this community can be explained by dispersal limitation. Comparing environmental factors, soil variables had higher explanatory power than did topography for species distribution. However, both topographic and edaphic variables were highly spatial structured. Our results suggested that dispersal limitation has an important influence on fine-intermediate scale (from several to tens of meters) species distribution, while environmental variability facilitates species distribution at intermediate (from ten to tens of meters) and broad (from tens to hundreds of meters) scales.

  12. Tree species distribution in temperate forests is more influenced by soil than by climate.

    Science.gov (United States)

    Walthert, Lorenz; Meier, Eliane Seraina

    2017-11-01

    Knowledge of the ecological requirements determining tree species distributions is a precondition for sustainable forest management. At present, the abiotic requirements and the relative importance of the different abiotic factors are still unclear for many temperate tree species. We therefore investigated the relative importance of climatic and edaphic factors for the abundance of 12 temperate tree species along environmental gradients. Our investigations are based on data from 1,075 forest stands across Switzerland including the cold-induced tree line of all studied species and the drought-induced range boundaries of several species. Four climatic and four edaphic predictors represented the important growth factors temperature, water supply, nutrient availability, and soil aeration. The climatic predictors were derived from the meteorological network of MeteoSwiss, and the edaphic predictors were available from soil profiles. Species cover abundances were recorded in field surveys. The explanatory power of the predictors was assessed by variation partitioning analyses with generalized linear models. For six of the 12 species, edaphic predictors were more important than climatic predictors in shaping species distribution. Over all species, abundances depended mainly on nutrient availability, followed by temperature, water supply, and soil aeration. The often co-occurring species responded similar to these growth factors. Drought turned out to be a determinant of the lower range boundary for some species. We conclude that over all 12 studied tree species, soil properties were more important than climate variables in shaping tree species distribution. The inclusion of appropriate soil variables in species distribution models allowed to better explain species' ecological niches. Moreover, our study revealed that the ecological requirements of tree species assessed in local field studies and in experiments are valid at larger scales across Switzerland.

  13. A Species Distribution Modeling Informed Conservation Assessment of Bog Spicebush

    Science.gov (United States)

    2016-09-14

    Adhikari, Barik , and Upadhaya 2012). These results sug- gest there are many locations potentially suitable for (re)introducing L. subcoriacea across its...References Adhikari, D., S. K. Barik , K. Upadhaya. 2012. Habitat distribution modelling for reintroduction of Ilex khasiana Purk., a critically

  14. Distribution of positive ion species above a diffuse midnight aurora

    International Nuclear Information System (INIS)

    Moore, T.E.

    1978-01-01

    The origin of the hot plasma in the Earth's magnetosphere is still open to investigation. Mass composition is an indicator of source region, while the distribution functions bear the signatures of transport and energization processes. Only ions identified as H + and He ++ were detected, and the He ++ was statistically marginal. Coincident magnetic storms are likely to play a crucial role in populating the magnetosphere with energized ionospheric ions. The measured proton distribution was nearly isotropic over downcoming pitch angles at all energies and showed a depleted atmospheric source cone. The high-altitude proton energy distribution had a best fit temperature of 4.5 keV and a number density of 0.17 cm- 3 , corresponding to a peak intensity just over 10 5 cm -2 s -1 sr -1 keV -1 . Altitudinal variations are consistent with the theory of charge exchange of a time-steady incident proton population. Simultaneous electron measurements can be interpreted in terms of an incident electron distribution that is also thermal wih a similar number density but a temperature of 2.5 keV. Taken together, the ion and electron data are consistent with the model of diffuse auroras in which plasma convecting in from the magnetospheric tail precipitates due to strong pitch angle diffusion on auroral field lines linking the near Earth plasma sheet

  15. Spatial distribution and habitat characterisation of mosquito species ...

    African Journals Online (AJOL)

    Background: Infections with mosquito-borne parasites are common in human populations inhabiting tropical regions of the world. Malaria is endemic along Kenyan Lake Victoria basin and its vectors are fresh water breeders. However, much less is known about the current spatial distribution and habitat characterisation of ...

  16. Species distribution and antifungal susceptibility profile of Candida ...

    African Journals Online (AJOL)

    HIV-AIDS. 0. 2. 2 (3.8%). Table 2: Distribution of candiduria in the hospital departments. Departments. Total number of patients. Number of positive patients .... Howard M, Cipher D, Revankar. SG. 2010. Occurrence of candiduria in a population of chronically catheterized patients with spinal cord injury. Spinal. Cord.,. 48(1):.

  17. Predicting Environmental Suitability for a Rare and Threatened Species (Lao Newt, Laotriton laoensis) Using Validated Species Distribution Models

    Science.gov (United States)

    Chunco, Amanda J.; Phimmachak, Somphouthone; Sivongxay, Niane; Stuart, Bryan L.

    2013-01-01

    The Lao newt (Laotriton laoensis) is a recently described species currently known only from northern Laos. Little is known about the species, but it is threatened as a result of overharvesting. We integrated field survey results with climate and altitude data to predict the geographic distribution of this species using the niche modeling program Maxent, and we validated these predictions by using interviews with local residents to confirm model predictions of presence and absence. The results of the validated Maxent models were then used to characterize the environmental conditions of areas predicted suitable for L. laoensis. Finally, we overlaid the resulting model with a map of current national protected areas in Laos to determine whether or not any land predicted to be suitable for this species is coincident with a national protected area. We found that both area under the curve (AUC) values and interview data provided strong support for the predictive power of these models, and we suggest that interview data could be used more widely in species distribution niche modeling. Our results further indicated that this species is mostly likely geographically restricted to high altitude regions (i.e., over 1,000 m elevation) in northern Laos and that only a minute fraction of suitable habitat is currently protected. This work thus emphasizes that increased protection efforts, including listing this species as endangered and the establishment of protected areas in the region predicted to be suitable for L. laoensis, are urgently needed. PMID:23555808

  18. Testing species distribution models across space and time: high latitude butterflies and recent warming

    DEFF Research Database (Denmark)

    Eskildsen, Anne; LeRoux, Peter C.; Heikkinen, Risto K.

    2013-01-01

    changes at expanding range margins can be predicted accurately. Location. Finland. Methods. Using 10-km resolution butterfly atlas data from two periods, 1992–1999 (t1) and 2002–2009 (t2), with a significant between-period temperature increase, we modelled the effects of climatic warming on butterfly...... butterfly distributions under climate change. Model performance was lower with independent compared to non-independent validation and improved when land cover and soil type variables were included, compared to climate-only models. SDMs performed less well for highly mobile species and for species with long......Aim. To quantify whether species distribution models (SDMs) can reliably forecast species distributions under observed climate change. In particular, to test whether the predictive ability of SDMs depends on species traits or the inclusion of land cover and soil type, and whether distributional...

  19. Topographic and spatial controls of palm species distributions in a montane rain forest, southern Ecuador

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Harlev, D.; Sørensen, M.M.

    2009-01-01

    The northern Andes harbour a flora that is as species-rich or even richer than the 18-times larger lowland Amazon basin. Gaining an understanding of how the high species richness of the Andean region is generated and maintained is therefore of particular interest. Environmental sorting due......). Mantel tests and indicator species analysis showed that both topography and spatial location imposed strong controls on palm species distributions at the study site. Our results suggest that species distributions in the studied montane forest landscape were partly determined by the species' habitat...... distributions at the study site. Other factors must also be involved, notably wind-exposure and hydrology, as discussed for lowland palm communities. Our results show that to understand plant community assembly in the tropical montane forests of the Andes it is too simple to focus just on environmental sorting...

  20. Updating known distribution models for forecasting climate change impact on endangered species.

    Science.gov (United States)

    Muñoz, Antonio-Román; Márquez, Ana Luz; Real, Raimundo

    2013-01-01

    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli's Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species' distribution, instead of building new models that are based on climate change variables only.

  1. Cross-species induction of antimicrobial compounds, biosurfactants and quorum-sensing inhibitors in tropical marine epibiotic bacteria by pathogens and biofouling microorganisms.

    Science.gov (United States)

    Dusane, Devendra H; Matkar, Pratiek; Venugopalan, Valayam P; Kumar, Ameeta Ravi; Zinjarde, Smita S

    2011-03-01

    Enhancement or induction of antimicrobial, biosurfactant, and quorum-sensing inhibition property in marine bacteria due to cross-species and cross-genera interactions was investigated. Four marine epibiotic bacteria (Bacillus sp. S3, B. pumilus S8, B. licheniformis D1, and Serratia marcescens V1) displaying antimicrobial activity against pathogenic or biofouling fungi (Candida albicans CA and Yarrowia lipolytica YL), and bacteria (Pseudomonas aeruginosa PA and Bacillus pumilus BP) were chosen for this study. The marine epibiotic bacteria when co-cultivated with the aforementioned fungi or bacteria showed induction or enhancement in antimicrobial activity, biosurfactant production, and quorum-sensing inhibition. Antifungal activity against Y. lipolytica YL was induced by co-cultivation of the pathogens or biofouling strains with the marine Bacillus sp. S3, B. pumilus S8, or B. licheniformis D1. Antibacterial activity against Ps. aeruginosa PA or B. pumilus BP was enhanced in most of the marine isolates after co-cultivation. Biosurfactant activity was significantly increased when cells of B. pumilus BP were co-cultivated with S. marcescens V1, B. pumilus S8, or B. licheniformis D1. Pigment reduction in the quorum-sensing inhibition indicator strain Chromobacterium violaceum 12472 was evident when the marine strain of Bacillus sp. S3 was grown in the presence of the inducer strain Ps. aeruginosa PA, suggesting quorum-sensing inhibition. The study has important ecological and biotechnological implications in terms of microbial competition in natural environments and enhancement of secondary metabolite production.

  2. Alien plant species list and distribution for Camdeboo National Park, Eastern Cape Province, South Africa

    Directory of Open Access Journals (Sweden)

    Mmoto L. Masubelele

    2009-09-01

    Full Text Available Protected areas globally are threatened by the potential negative impacts that invasive alien plants pose, and Camdeboo National Park (CNP, South Africa, is no exception. Alien plants have been recorded in the CNP since 1981, before it was proclaimed a national park by South African National Parks in 2005. This is the first publication of a list of alien plants in and around the CNP. Distribution maps of some of the first recorded alien plant species are also presented and discussed. To date, 39 species of alien plants have been recorded, of which 13 are invasive and one is a transformer weed. The majority of alien plant species in the park are herbaceous (39% and succulent (24% species. The most widespread alien plant species in the CNP are Atriplex inflata (= A. lindleyi subsp. inflata, Salsola tragus (= S. australis and cacti species, especially Opuntia ficus-indica. Eradication and control measures that have been used for specific problematic alien plant species are described. Conservation implications: This article represents the first step in managing invasive alien plants and includes the collation of a species list and basic information on their distribution in and around the protected area. This is important for enabling effective monitoring of both new introductions and the distribution of species already present. We present the first species list and distribution information for Camdeboo National Park.

  3. Asymmetric biotic interactions and abiotic niche differences revealed by a dynamic joint species distribution model.

    Science.gov (United States)

    Lany, Nina K; Zarnetske, Phoebe L; Schliep, Erin M; Schaeffer, Robert N; Orians, Colin M; Orwig, David A; Preisser, Evan L

    2018-05-01

    A species' distribution and abundance are determined by abiotic conditions and biotic interactions with other species in the community. Most species distribution models correlate the occurrence of a single species with environmental variables only, and leave out biotic interactions. To test the importance of biotic interactions on occurrence and abundance, we compared a multivariate spatiotemporal model of the joint abundance of two invasive insects that share a host plant, hemlock woolly adelgid (HWA; Adelges tsugae) and elongate hemlock scale (EHS; Fiorina externa), to independent models that do not account for dependence among co-occurring species. The joint model revealed that HWA responded more strongly to abiotic conditions than EHS. Additionally, HWA appeared to predispose stands to subsequent increase of EHS, but HWA abundance was not strongly dependent on EHS abundance. This study demonstrates how incorporating spatial and temporal dependence into a species distribution model can reveal the dependence of a species' abundance on other species in the community. Accounting for dependence among co-occurring species with a joint distribution model can also improve estimation of the abiotic niche for species affected by interspecific interactions. © 2018 by the Ecological Society of America.

  4. Comparative in vitro activities of nemonoxacin, doripenem, tigecycline and 16 other antimicrobials against Nocardia brasiliensis, Nocardia asteroides and unusual Nocardia species.

    Science.gov (United States)

    Lai, Chih-Cheng; Tan, Che-Kim; Lin, Sheng Hsiang; Liao, Chun-Hsing; Chou, Chien-Hong; Hsu, Hsiao-Leng; Huang, Yu-Tsung; Hsueh, Po-Ren

    2009-07-01

    The aim of this study was to assess the in vitro activities of nemonoxacin (a novel non-fluorinated quinolone), doripenem, tigecycline and 16 other antimicrobial agents against the Nocardia species. MICs of 19 antimicrobial agents for 125 clinical isolates of the Nocardia species were determined by the broth microdilution method. Nocardia brasiliensis (n = 61), Nocardia asteroides (n = 45), Nocardia flavorosea (n = 5), Nocardia otitidiscaviarum (n = 4), Nocardia farcinica (n = 3), Nocardia beijingensis (n = 2), Nocardia puris (n = 2) and one each of Nocardia nova, Nocardia jinanensis and Nocardia takedensis were identified based on a 16S rRNA gene sequencing analysis. For N. brasiliensis isolates, the MIC(90)s of the tested quinolones were in the order nemonoxacin Nocardia species isolates, nemonoxacin showed good activity with the lowest MIC(90) of the tested quinolones. Among the four tested carbapenems, doripenem and meropenem had comparatively lower MIC(90)s. The results of this in vitro study suggest that nemonoxacin, linezolid and tigecycline show promise as treatment options for nocardiosis. Further investigation of their clinical role is warranted.

  5. Temperature effects on gametophyte life-history traits and geographic distribution of two cryptic kelp species.

    Directory of Open Access Journals (Sweden)

    L Valeria Oppliger

    Full Text Available A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29-30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1 estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2 compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed.

  6. Antimicrobial activity of Tulsi (Ocimum tenuiflorum essential oil and their major constituents against three species of bacteria

    Directory of Open Access Journals (Sweden)

    Hanaa Abbas M Yamani

    2016-05-01

    Full Text Available In recent years scientists worldwide have realized that the effective life span of any antimicrobial agent is limited, due to increasing development of resistance by microorganisms. Consequently, numerous studies have been conducted to find new alternative sources of antimicrobial agents, especially from plants. The aims of this project were to examine the antimicrobial properties of essential oils distilled from Australian-grown Ocimum teniflorum (Tulsi, to quantify the volatile components present in flower spikes, leaves and the essential oil, and to investigate the compounds responsible for any activity. Broth micro-dilution was used to determine the minimum inhibitory concentration (MIC of Tulsi essential oil against selected microbial pathogens. The oils, at concentrations of 4.5% and 2.25% completely inhibited the growth of Staphylococcus aureus (including MRSA and Escherichia coli, while the same concentrations only partly inhibited the growth of Pseudomonas aeruginosa. Of 54 compounds identified in Tulsi leaves, flower spikes or essential oil, three are proposed to be responsible for this activity; camphor, eucalyptol and eugenol. Since S. aureus (including MRSA, P. aeruginosa and E. coli are major pathogens causing skin and soft tissue infections, Tulsi essential oil could be a valuable topical antimicrobial agent for management of skin infections caused by these organisms.

  7. Antimicrobial resistance patterns of Staphylococcus species isolated from cats presented at a veterinary academic hospital in South Africa.

    Science.gov (United States)

    Qekwana, Daniel Nenene; Sebola, Dikeledi; Oguttu, James Wabwire; Odoi, Agricola

    2017-09-15

    Antimicrobial resistance is becoming increasingly important in both human and veterinary medicine. This study investigated the proportion of antimicrobial resistant samples and resistance patterns of Staphylococcus isolates from cats presented at a veterinary teaching hospital in South Africa. Records of 216 samples from cats that were submitted to the bacteriology laboratory of the University of Pretoria academic veterinary hospital between 2007 and 2012 were evaluated. Isolates were subjected to antimicrobial susceptibility testing against a panel of 15 drugs using the disc diffusion method. Chi square and Fisher's exact tests were used to assess simple associations between antimicrobial resistance and age group, sex, breed and specimen type. Additionally, associations between Staphylococcus infection and age group, breed, sex and specimen type were assessed using logistic regression. Staphylococcus spp. isolates were identified in 17.6% (38/216) of the samples submitted and 4.6% (10/216) of these were unspeciated. The majority (61.1%,11/18) of the isolates were from skin samples, followed by otitis media (34.5%, 10/29). Coagulase Positive Staphylococcus (CoPS) comprised 11.1% (24/216) of the samples of which 7.9% (17/216) were S. intermedius group and 3.2% (7/216) were S. aureus. Among the Coagulase Negative Staphylococcus (CoNS) (1.9%, 4/216), S. felis and S. simulans each constituted 0.9% (2/216). There was a significant association between Staphylococcus spp. infection and specimen type with odds of infection being higher for ear canal and skin compared to urine specimens. There were higher proportions of samples resistant to clindamycin 34.2% (13/25), ampicillin 32.4% (2/26), lincospectin 31.6% (12/26) and penicillin-G 29.0% (11/27). Sixty three percent (24/38) of Staphylococcus spp. were resistant to one antimicrobial agent and 15.8% were multidrug resistant (MDR). MDR was more common among S. aureus 28.6% (2/7) than S. intermedius group isolates 11.8% (2

  8. Geographical Distribution of Taenia asiatica and Related Species

    Science.gov (United States)

    Jeon, Hyeong-Kyu; Rim, Han-Jong

    2009-01-01

    Geographical information of Taenia asiatica is reviewed together with that of T. solium and T. saginata. Current distribution of T. asiatica was found to be mostly from Asian countries: the Republic of Korea, China, Taiwan, Indonesia, and Thailand. Molecular genotypic techniques have found out more countries with T. asiatica from Japan, the Philippines, and Vietnam. Specimens used in this paper were collected from around the world and mostly during international collaboration projects of Korean foundations for parasite control activities (1995-2009) in developing countries. PMID:19885327

  9. Spatially-explicit estimation of geographical representation in large-scale species distribution datasets.

    Science.gov (United States)

    Kalwij, Jesse M; Robertson, Mark P; Ronk, Argo; Zobel, Martin; Pärtel, Meelis

    2014-01-01

    Much ecological research relies on existing multispecies distribution datasets. Such datasets, however, can vary considerably in quality, extent, resolution or taxonomic coverage. We provide a framework for a spatially-explicit evaluation of geographical representation within large-scale species distribution datasets, using the comparison of an occurrence atlas with a range atlas dataset as a working example. Specifically, we compared occurrence maps for 3773 taxa from the widely-used Atlas Florae Europaeae (AFE) with digitised range maps for 2049 taxa of the lesser-known Atlas of North European Vascular Plants. We calculated the level of agreement at a 50-km spatial resolution using average latitudinal and longitudinal species range, and area of occupancy. Agreement in species distribution was calculated and mapped using Jaccard similarity index and a reduced major axis (RMA) regression analysis of species richness between the entire atlases (5221 taxa in total) and between co-occurring species (601 taxa). We found no difference in distribution ranges or in the area of occupancy frequency distribution, indicating that atlases were sufficiently overlapping for a valid comparison. The similarity index map showed high levels of agreement for central, western, and northern Europe. The RMA regression confirmed that geographical representation of AFE was low in areas with a sparse data recording history (e.g., Russia, Belarus and the Ukraine). For co-occurring species in south-eastern Europe, however, the Atlas of North European Vascular Plants showed remarkably higher richness estimations. Geographical representation of atlas data can be much more heterogeneous than often assumed. Level of agreement between datasets can be used to evaluate geographical representation within datasets. Merging atlases into a single dataset is worthwhile in spite of methodological differences, and helps to fill gaps in our knowledge of species distribution ranges. Species distribution

  10. Species Distribution Modelling of Aedes aegypti in two dengue-endemic regions of Pakistan.

    Science.gov (United States)

    Fatima, Syeda Hira; Atif, Salman; Rasheed, Syed Basit; Zaidi, Farrah; Hussain, Ejaz

    2016-03-01

    Statistical tools are effectively used to determine the distribution of mosquitoes and to make ecological inferences about the vector-borne disease dynamics. In this study, we utilised species distribution models to understand spatial patterns of Aedes aegypti in two dengue-prevalent regions of Pakistan, Lahore and Swat. Species distribution models can potentially indicate the probability of suitability of Ae. aegypti once introduced to new regions like Swat, where invasion of this species is a recent phenomenon. The distribution of Ae. aegypti was determined by applying the MaxEnt algorithm on a set of potential environmental factors and species sample records. The ecological dependency of species on each environmental variable was analysed using response curves. We quantified the statistical performance of the models based on accuracy assessment and spatial predictions. Our results suggest that Ae. aegypti is widely distributed in Lahore. Human population density and urban infrastructure are primarily responsible for greater probability of mosquito occurrence in this region. In Swat, Ae. aegypti has clumped distribution, where urban patches provide refuge to the species in an otherwise hostile heterogeneous environment and road networks are assumed to have facilitated in passive-mediated dispersal of species. In Pakistan, Ae. aegypti is expanding its range northwards; this could be associated with rapid urbanisation, trade and travel. The main implication of this expansion is that more people are at risk of dengue fever in the northern highlands of Pakistan. © 2016 John Wiley & Sons Ltd.

  11. Species distribution model transferability and model grain size - finer may not always be better.

    Science.gov (United States)

    Manzoor, Syed Amir; Griffiths, Geoffrey; Lukac, Martin

    2018-05-08

    Species distribution models have been used to predict the distribution of invasive species for conservation planning. Understanding spatial transferability of niche predictions is critical to promote species-habitat conservation and forecasting areas vulnerable to invasion. Grain size of predictor variables is an important factor affecting the accuracy and transferability of species distribution models. Choice of grain size is often dependent on the type of predictor variables used and the selection of predictors sometimes rely on data availability. This study employed the MAXENT species distribution model to investigate the effect of the grain size on model transferability for an invasive plant species. We modelled the distribution of Rhododendron ponticum in Wales, U.K. and tested model performance and transferability by varying grain size (50 m, 300 m, and 1 km). MAXENT-based models are sensitive to grain size and selection of variables. We found that over-reliance on the commonly used bioclimatic variables may lead to less accurate models as it often compromises the finer grain size of biophysical variables which may be more important determinants of species distribution at small spatial scales. Model accuracy is likely to increase with decreasing grain size. However, successful model transferability may require optimization of model grain size.

  12. Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

    Directory of Open Access Journals (Sweden)

    Loïc ePellissier

    2013-12-01

    Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

  13. [Species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China].

    Science.gov (United States)

    Zhang, Qian; Zhong, Jin-Xin

    2013-05-01

    Based on the related published papers, and by using Geographic Information System (ArcGIS 9.3), this paper analyzed the species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China. There were 83 threatened species living in the Province, belonging to 5 orders, 13 families, and 47 genera. Cypriniformes was absolutely dominant, with 64 species, followed by Siluriformes, with 16 species. Cyprinidae fishes had 51 species, accounting for 79.7% of Cypriniformes. The most species of Cyprinid fishes were of Barbinae (14 species), Cyprininae (10 species), and Cultrinae (10 species). The threatened fishes could be divided into two zoogeographical regions, i. e., Tibetan Plateau region and Oriental region, and their species composition and geographical distribution were resulted from the historical evolution adapted to the related environments. Whatever in rivers and in lakes, the Cyprinid fishes were both absolutely dominant, occupying 36.1% and 31.3% of the total, respectively. The Cyprinid fishes in rivers were mostly of endangered species, while those in lakes were mostly of vulnerable species. The factors affecting the threatened fishes in the Province were discussed from the two aspects of geodynamic evolution and present situation.

  14. The prevalence and distribution of Fusarium species in Norwegian cereals: a survey

    DEFF Research Database (Denmark)

    Kosiak, B.; Torp, M.; Skjerve, E.

    2003-01-01

    the regions. A total of 695 grain samples were analysed. The amount of Fusarium infection varied with cereal species and region of origin. The most frequently isolated Fusarium spp. from all samples were F. avenaceum, F. poae, F. tricinctum and F. culmorum. Other important toxigenic Fusarium spp. were F......In the period 1994-1996 a post-harvest survey was conducted in wheat, barley and oats to assess the occurrence and geographic distribution of Fusarium species in Norwegian cereals. The number of samples investigated was adjusted proportionally to the production of each cereal species within...... and F. culmorum demonstrated in this study , corresponded to previously reported DON-distribution, although DON seems to be produced by different species in different regions. Distribution of the isolated Fusarium species and comparison between cereals and locations are discussed....

  15. Vertical distribution and migration of euphausiid species in the Red Sea

    KAUST Repository

    Wiebe, Peter H.; Bucklin, Ann; Kaartvedt, Stein; Rø stad, Anders; Blanco-Bercial, Leocadio

    2016-01-01

    We addressed how the extreme environmental conditions of the Red Sea impact or alter patterns of vertical distribution and vertical migration of five euphausiid species that are known from other oceans. Euphausia diomedeae was abundant and performed

  16. Distribution of antimicrobial resistance determinants, virulence-associated factors and clustered regularly interspaced palindromic repeats loci in isolates of Enterococcus faecalis from various settings and genetic lineages.

    Science.gov (United States)

    Gawryszewska, Iwona; Malinowska, Katarzyna; Kuch, Alicja; Chrobak-Chmiel, Dorota; Trokenheim, Lucja Laniewska-; Hryniewicz, Waleria; Sadowy, Ewa

    2017-03-01

    Enterococcus faecalis represents an important factor of hospital-associated infections (HAIs). The knowledge on its evolution from a commensal to an opportunistic pathogen is still limited; thus, we performed a study to characterise distribution of factors that may contribute to this adaptation. Using a collection obtained from various settings (hospitalised patients, community carriers, animals, fresh food, sewage, water), we investigated differences in antimicrobial susceptibility, distribution of antimicrobial resistance genes, virulence-associated determinants and phenotypes, and CRISPR loci in the context of the clonal relatedness of isolates. Bayesian Analysis of Population Structure revealed the presence of three major groups; two subgroups comprised almost exclusively HAI isolates, belonging to previously proposed enterococcal high-risk clonal complexes (HiRECCs) 6 and 28. Isolates of these two subgroups were significantly enriched in antimicrobial resistance genes, presumably produced a polysaccharide capsule and often carried the aggregation substance asa1; distribution of other virulence-associated genes, such as esp and cyl, formation of a biofilm and gelatinase production were more variable. Moreover, both subgroups showed a low prevalence of CRISPR-Cas 1 and 3 and presence of small CRISPR2 variants. Our study confirms the importance of HiRECCs in the population of E. faecalis and their confinement to the hospital settings. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents.

    Science.gov (United States)

    Poorter, Hendrik; Jagodzinski, Andrzej M; Ruiz-Peinado, Ricardo; Kuyah, Shem; Luo, Yunjian; Oleksyn, Jacek; Usoltsev, Vladimir A; Buckley, Thomas N; Reich, Peter B; Sack, Lawren

    2015-11-01

    We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  18. The effects of global change on the distribution, species richness and life history of European dragonflies

    DEFF Research Database (Denmark)

    Olsen, Kent

    2016-01-01

    traits such as taxonomy, habitat specificity, metabolic plasticity, and biogeographic traits such zoogeographical origin. In Paper I we describe how changes in species richness pattern across Europe correlate with range changes in different taxonomic and biogeographic groups of dragonflies. We found...... specialized species adapted to permanent running (perennial lotic) water habitats. We found that species reproducing in temporary water track climate changes better than species adapted to permanent water. In Paper III we explore the relationship between metabolic plasticity (expressed as the ability to shift...... with less metabolic plasticity. We conducted experimental ex-situ measurements of metabolic rates measured as respiration rates at 10°C and 20°C, respectively, of four Scandinavian dragonfly species. We used two species with a northern distribution, one with a southern distribution and one ubiquitous...

  19. [Effects of sampling plot number on tree species distribution prediction under climate change].

    Science.gov (United States)

    Liang, Yu; He, Hong-Shi; Wu, Zhi-Wei; Li, Xiao-Na; Luo, Xu

    2013-05-01

    Based on the neutral landscapes under different degrees of landscape fragmentation, this paper studied the effects of sampling plot number on the prediction of tree species distribution at landscape scale under climate change. The tree species distribution was predicted by the coupled modeling approach which linked an ecosystem process model with a forest landscape model, and three contingent scenarios and one reference scenario of sampling plot numbers were assumed. The differences between the three scenarios and the reference scenario under different degrees of landscape fragmentation were tested. The results indicated that the effects of sampling plot number on the prediction of tree species distribution depended on the tree species life history attributes. For the generalist species, the prediction of their distribution at landscape scale needed more plots. Except for the extreme specialist, landscape fragmentation degree also affected the effects of sampling plot number on the prediction. With the increase of simulation period, the effects of sampling plot number on the prediction of tree species distribution at landscape scale could be changed. For generalist species, more plots are needed for the long-term simulation.

  20. The geography of demography: long-term demographic studies and species distribution models reveal a species border limited by adaptation.

    Science.gov (United States)

    Eckhart, V M; Geber, M A; Morris, W F; Fabio, E S; Tiffin, P; Moeller, D A

    2011-10-01

    Potential causes of species' geographic distribution limits fall into two broad classes: (1) limited adaptation across spatially variable environments and (2) limited opportunities to colonize unoccupied areas. Combining demographic studies, analyses of demographic responses to environmental variation, and species distribution models, we investigated the causes of range limits in a model system, the eastern border of the California annual plant Clarkia xantiana ssp. xantiana. Vital rates of 20 populations varied with growing season temperature and precipitation: fruit number and overwinter survival of 1-year-old seeds declined steeply, while current-year seed germination increased modestly along west-to-east gradients in decreasing temperature, decreasing mean precipitation, and increasing variation in precipitation. Long-term stochastic finite rate of increase, λ(s), exhibited a fourfold range and varied among geologic surface materials as well as with temperature and precipitation. Growth rate declined significantly toward the eastern border, falling below 1 in three of the five easternmost populations. Distribution models employing demographically important environmental variables predicted low habitat favorability beyond the eastern border. Models that filtered or weighted population presences by λ(s) predicted steeper eastward declines in favorability and assigned greater roles in setting the distribution to among-year variation in precipitation and to geologic surface material. These analyses reveal a species border likely set by limited adaptation to declining environmental quality.

  1. Modeling the Distribution of Rare or Cryptic Bird Species of Taiwan

    Directory of Open Access Journals (Sweden)

    Tsai-Yu Wu

    2012-12-01

    Full Text Available For the study of the macroecology and conservation of Taiwan’s birds, there was an urgent need to develop distribution models of bird species whose distribution had never before been modeled. Therefore, we here model the distributions of 27 mostly rare and cryptic breeding bird species using a statistical approach which has been shown to be especially reliable for modeling species with a low sample size of presence localities, namely the maximum entropy (Maxent modeling technique. For this purpose, we began with a dedicated attempt to collate as much high-quality distributional data as possible, assembling databases from several scientific reports, contacting individual data recorders and searching publicly accessible database, the internet and the available literature. This effort resulted in 2022 grid cells of 1 × 1 km size being associated with a presence record for one of the 27 species. These records and 10 pre-selected environmental variables were then used to model each species’ probability distribution which we show here with all grid cells below the lowest presence threshold being converted to zeros. We then in detail discuss the interpretation and applicability of these distributions, whereby we pay close attention to habitat requirements, the intactness and fragmentation of their habitat, the general detectability of the species and data reliability. This study is another one in an ongoing series of studies which highlight the usefulness of using large electronic databases and modern analytical methods to help with the monitoring and assessment of Taiwan’s bird species.

  2. The predictive skill of species distribution models for plankton in a changing climate

    DEFF Research Database (Denmark)

    Brun, Philipp Georg; Kiørboe, Thomas; Licandro, Priscilla

    2016-01-01

    Statistical species distribution models (SDMs) are increasingly used to project spatial relocations of marine taxa under future climate change scenarios. However, tests of their predictive skill in the real-world are rare. Here, we use data from the Continuous Plankton Recorder program, one...... null models, is essential to assess the robustness of projections of marine planktonic species under climate change...

  3. An analysis of plant species distributions on the floodplain of the ...

    African Journals Online (AJOL)

    Furthermore, several ruderal species were restricted to elevated sites in close proximity to the channel, occurring on recently formed point bars which are the product of fluvial processes. Disturbance in the form of sediment deposition on point bars is thus an important determinant of species distribution on floodplains of the ...

  4. A new record of Oxychilus alliarius (Gastropoda: Zonitidae with the species distribution in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Jitka Horáčková

    2009-12-01

    Full Text Available A new finding of the land snail species Oxychilus alliarius was recorded in the Czech Republic. This West European species was found in the six isolated sites during the last thirteen years always in western part of Bohemia. This paper brings new information on the distribution of Oxychilus alliarius in the Czech Republic.

  5. Global checklist of species of Grania (Clitellata: Enchytraeidae with remarks on their geographic distribution

    Directory of Open Access Journals (Sweden)

    Alessandro Prantoni

    2017-12-01

    Full Text Available A checklist of all currently accepted species of Grania Southern, 1913 (Annelida, Clitellata, Enchytraeidae is presented. The genus is widespread over the world and comprises 81 species described to date. Remarks on their geographical distribution, habitat, synonymies and museum catalogue numbers are provided.

  6. Linking macroecology and community ecology: refining predictions of species distributions using biotic interaction networks.

    Science.gov (United States)

    Staniczenko, Phillip P A; Sivasubramaniam, Prabu; Suttle, K Blake; Pearson, Richard G

    2017-06-01

    Macroecological models for predicting species distributions usually only include abiotic environmental conditions as explanatory variables, despite knowledge from community ecology that all species are linked to other species through biotic interactions. This disconnect is largely due to the different spatial scales considered by the two sub-disciplines: macroecologists study patterns at large extents and coarse resolutions, while community ecologists focus on small extents and fine resolutions. A general framework for including biotic interactions in macroecological models would help bridge this divide, as it would allow for rigorous testing of the role that biotic interactions play in determining species ranges. Here, we present an approach that combines species distribution models with Bayesian networks, which enables the direct and indirect effects of biotic interactions to be modelled as propagating conditional dependencies among species' presences. We show that including biotic interactions in distribution models for species from a California grassland community results in better range predictions across the western USA. This new approach will be important for improving estimates of species distributions and their dynamics under environmental change. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  7. Frequency, antimicrobial susceptibility and clonal distribution of methicillin-resistant Staphylococcus pseudintermedius in canine clinical samples submitted to a veterinary diagnostic laboratory in Italy: A 3-year retrospective investigation

    DEFF Research Database (Denmark)

    Ventrella, G.; Moodley, A.; Grandolfo, E.

    2017-01-01

    In the last decade there has been a rapid global spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) clones displaying multidrug resistance in dogs. We investigated prevalence, antimicrobial susceptibility and clonal distribution of MRSP isolated from clinical canine samples be...

  8. Chemical Composition and in-Vitro Evaluation of the Antimicrobial and Antioxidant Activities of Essential Oils Extracted from Seven Eucalyptus Species

    Directory of Open Access Journals (Sweden)

    Abdul Ghaffar

    2015-11-01

    Full Text Available Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan. EOs from Eucalyptus citriodora, Eucalyptus melanophloia, Eucalyptus crebra, Eucalyptus tereticornis, Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus microtheca were extracted from leaves through hydrodistillation. The chemical composition of the EOs was determined through GC-MS-FID analysis. The study revealed presence of 31 compounds in E. citriodora and E. melanophloia, 27 compounds in E. crebra, 24 compounds in E. tereticornis, 10 compounds in E. globulus, 13 compounds in E. camaldulensis and 12 compounds in E. microtheca. 1,8-Cineole (56.5%, α-pinene (31.4%, citrinyl acetate (13.3%, eugenol (11.8% and terpenene-4-ol (10.2% were the highest principal components in these EOs. E. citriodora exhibited the highest antimicrobial activity against the five microbial species tested (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Rhizopus solani. Gram positive bacteria were found more sensitive than Gram negative bacteria to all EOs. The diphenyl-1-picrylhydazyl (DPPH radical scavenging activity and percentage inhibition of linoleic acid oxidation were highest in E. citriodora (82.1% and 83.8%, respectively followed by E. camaldulensis (81.9% and 83.3%, respectively. The great variation in chemical composition of EOs from Eucalyptus, highlight its potential for medicinal and nutraceutical applications.

  9. Chemical Composition and in-Vitro Evaluation of the Antimicrobial and Antioxidant Activities of Essential Oils Extracted from Seven Eucalyptus Species.

    Science.gov (United States)

    Ghaffar, Abdul; Yameen, Muhammad; Kiran, Shumaila; Kamal, Shagufta; Jalal, Fatima; Munir, Bushra; Saleem, Sadaf; Rafiq, Naila; Ahmad, Aftab; Saba, Iram; Jabbar, Abdul

    2015-11-18

    Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs) extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan). EOs from Eucalyptus citriodora, Eucalyptus melanophloia, Eucalyptus crebra, Eucalyptus tereticornis, Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus microtheca were extracted from leaves through hydrodistillation. The chemical composition of the EOs was determined through GC-MS-FID analysis. The study revealed presence of 31 compounds in E. citriodora and E. melanophloia, 27 compounds in E. crebra, 24 compounds in E. tereticornis, 10 compounds in E. globulus, 13 compounds in E. camaldulensis and 12 compounds in E. microtheca. 1,8-Cineole (56.5%), α-pinene (31.4%), citrinyl acetate (13.3%), eugenol (11.8%) and terpenene-4-ol (10.2%) were the highest principal components in these EOs. E. citriodora exhibited the highest antimicrobial activity against the five microbial species tested (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Rhizopus solani). Gram positive bacteria were found more sensitive than Gram negative bacteria to all EOs. The diphenyl-1-picrylhydazyl (DPPH) radical scavenging activity and percentage inhibition of linoleic acid oxidation were highest in E. citriodora (82.1% and 83.8%, respectively) followed by E. camaldulensis (81.9% and 83.3%, respectively). The great variation in chemical composition of EOs from Eucalyptus, highlight its potential for medicinal and nutraceutical applications.

  10. High-throughput fluorescence screening assay for the identification and comparison of antimicrobial peptides’ activity on various yeast species

    Czech Academy of Sciences Publication Activity Database

    Kodedová, Marie; Sychrová, Hana

    2016-01-01

    Roč. 233, Sep 10 (2016), s. 26-33 ISSN 0168-1656 R&D Projects: GA TA ČR(CZ) TA04010638; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : diS-C3(3) assay * antimicrobial peptide * Candida * membrane potential * microplate reader Subject RIV: EE - Microbiology, Virology Impact factor: 2.599, year: 2016

  11. Species distribution and drug susceptibility of candida in clinical isolates from a tertiary care centre at Indore

    Directory of Open Access Journals (Sweden)

    N Pahwa

    2014-01-01

    Full Text Available Background: The incidence of fungal infections has increased significantly, contributing to morbidity and mortality. This is caused by an alarming increase in infections with multi-drug resistant bacteria leading to overuse of broad-spectrum antimicrobials, which lead to overgrowth of Candida, thus enhancing its opportunity to cause disease. Candida are major human fungal pathogens that cause both mucosal and deep tissue infections. Objective : The aim of our study was to identify the distribution of Candida species among clinical isolates and their sensitivity pattern for common antifungal drugs. Materials and Methods : Two hundred and thirty-seven different clinical isolates of Candida were collected from patients visiting to a tertiary care centre of Indore from 2010 to 2012. Identification of Candida species as well as antifungal sensitivity testing was performed with Vitek2 Compact (Biomerieux France using vitek 2 cards for identification of yeast and yeast like organisms (ID-YST cards. Antifungal susceptibility testing was performed with Vitek2 "Fungal Susceptibility Card (AST YS01 kits respectively. Results : We found that the non-albicans Candida were more prevalent than Candida albicans in paediatric (60 year patients than other age group (4-18, 19-60 years patients and also in intensive care unit (ICU patients as compared to out patient department (OPD patients. Resistance rates for amphotericin B, fluconazole, flucytosine, itraconazole, and voriconazole were 2.9%, 5.9%, 0.0%, 4.2% and 2.5%%, respectively. All the strains of C. krusei were found resistant to fluconazole with intermediate sensitivity to flucytosine. Conclusion: Species-level identification of Candida and their antifungal sensitivity testing should be performed to achieve better clinical results.

  12. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... produced material may be copied, reproduced, and distributed as long as FDA's Center for Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance ( ...

  13. Continental-wide distribution of crayfish species in Europe: update and maps

    Directory of Open Access Journals (Sweden)

    Kouba A.

    2014-01-01

    Full Text Available Recently published astacological studies substantially improved available data on distribution of crayfish in various European regions. At the same time, spread of invasive species has been recorded, additional non-indigenous species became established in various countries, and losses of populations of native species due to crayfish plague and other negative factors were observed. We overview recent advances in this knowledge, and provide updated colour maps of the distribution of all crayfish species present in Europe. These maps are originally based on the data from the Atlas of Crayfish in Europe published in 2006 as a result of the CRAYNET project, and were further updated from more recently published reports, grey literature, and especially thanks to contributions and feedback of over 70 specialists from 32 countries. Separate maps are available for all indigenous crayfish species in Europe as well as for three most widespread non-indigenous crayfish species. Additionally, two maps give locations of known findings of crayfish species introduced to Europe after 1980. These newly established alien species have so far restricted distributions; however, the frequency of recent reports suggests that findings of such species resulting from releases of aquarium pets will further increase.

  14. [Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

    Science.gov (United States)

    Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

    2017-12-01

    The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

  15. Predicting plant invasions under climate change: are species distribution models validated by field trials?

    Science.gov (United States)

    Sheppard, Christine S; Burns, Bruce R; Stanley, Margaret C

    2014-09-01

    Climate change may facilitate alien species invasion into new areas, particularly for species from warm native ranges introduced into areas currently marginal for temperature. Although conclusions from modelling approaches and experimental studies are generally similar, combining the two approaches has rarely occurred. The aim of this study was to validate species distribution models by conducting field trials in sites of differing suitability as predicted by the models, thus increasing confidence in their ability to assess invasion risk. Three recently naturalized alien plants in New Zealand were used as study species (Archontophoenix cunninghamiana, Psidium guajava and Schefflera actinophylla): they originate from warm native ranges, are woody bird-dispersed species and of concern as potential weeds. Seedlings were grown in six sites across the country, differing both in climate and suitability (as predicted by the species distribution models). Seedling growth and survival were recorded over two summers and one or two winter seasons, and temperature and precipitation were monitored hourly at each site. Additionally, alien seedling performances were compared to those of closely related native species (Rhopalostylis sapida, Lophomyrtus bullata and Schefflera digitata). Furthermore, half of the seedlings were sprayed with pesticide, to investigate whether enemy release may influence performance. The results showed large differences in growth and survival of the alien species among the six sites. In the more suitable sites, performance was frequently higher compared to the native species. Leaf damage from invertebrate herbivory was low for both alien and native seedlings, with little evidence that the alien species should have an advantage over the native species because of enemy release. Correlations between performance in the field and predicted suitability of species distribution models were generally high. The projected increase in minimum temperature and reduced

  16. The effects of drainage on groundwater quality and plant species distribution in stream valley meadows

    NARCIS (Netherlands)

    Grootjans, A.P.; Diggelen, R. van; Wassen, M.J.; Wiersinga, W.A.

    1988-01-01

    Conditions in fen meadows in Dutch stream valleys are influenced by both deep (Ca2+-rich) and shallow (Ca2+-poor) groundwater flows. The distribution patterns of phreatophytic (groundwater-influenced) plant species showed distinct relationships with the distribution of different groundwater types.

  17. Predictive models of threatened plant species distribution in the Iberian arid south-east

    OpenAIRE

    Benito, Blas M.

    2013-01-01

    Poster on the distribution of three rare, endemic and endangered annual plants of arid zones in the south-eastern Iberian peninsula. Presented in the workshop "Predictive Modelling of Species Distribution: New Tools for the XXI Century (Baeza, Spain, november 2005).

  18. Distribution and Antimicrobial Susceptibility of Foodborne Salmonella Serovars in Eight Provinces in China from 2007 to 2012 (Except 2009).

    Science.gov (United States)

    Wang, Yin; Cao, Chenyang; Alali, Walid Q; Cui, Shenghui; Li, Fengqin; Zhu, Jianghui; Wang, Xin; Meng, Jianghong; Yang, Baowei

    2017-07-01

    One thousand four hundred ninety-one Salmonella isolates recovered from retail foods including chicken, beef, fish, pork, dumplings, and cold dishes in China in 2007, 2008, 2010, 2011, and 2012 were analyzed for distribution of serotype and antimicrobial susceptibility. A total of 129 Salmonella serotypes were detected among 1491 isolates. Salmonella Enteritidis (21.5%), Typhimurium (11.0%), Indiana (10.8%), Thompson (5.4%), Derby (5.1%), Agona (3.8%), and Shubra (3.0%) were the seven most important serotypes in 1491 isolates. For antibiotic susceptibility, except 16 (1.1%) isolates were susceptible to all tested antibiotics, 131 (8.8%) resisted 1-2 and 1344 (90.1%) resisted three or more antibiotics. One thousand forty-six (70.2%) of 1491 Salmonella isolates were identified as multidrug-resistant (MDR) isolates, which could resist three or more categories of antibiotics. Resistance to sulfisoxazole (78.1%) was most common among the tested Salmonella, followed by tetracycline (70.6%), trimethoprim/sulfamethoxazole (68.0%), and nalidixic acid (63.4%). Resistances to amikacin (20.0%), levofloxacin (18.7%), gatifloxacin (17.9%), ceftriaxone (17.7%), and cefoxitin (13.2%) were less frequently detected. Resistance to fluoroquinolones was most common among Salmonella Shubra and Indiana isolates, while resistance to cephalosporins was frequently detected among Salmonella Thompson isolates. The results highlighted the diversity of Salmonella serotypes and the high prevalence of Salmonella MDR isolates in China. Compared with Salmonella Enteritidis and Typhimurium isolates, the higher fluoroquinolones and cephalosporins resistance rates of some individual serotypes (Salmonella Shubra, Indiana, and Thompson) also provided more information for further study related to fluoroquinolones or cephalosporin-resistant Salmonella.

  19. Determination of antimicrobial and heavy metal resistance profiles of some bacteria isolated from aquatic amphibian and reptile species.

    Science.gov (United States)

    Hacioglu, Nurcihan; Tosunoglu, Murat

    2014-01-01

    The aim of the present study was to determine the level of antibiotic resistance patterns and distribution of heavy metal resistance of bacterial isolates from aquatic animals (Lissotriton vulgaris, Pelophylax ridibundus, Emys orbicularis, Mauremys rivulata, and Natrix natrix) in Turkey (Kavak Delta). A total of 153 bacteria have been successfully isolated from cloaca and oral samples of the aquatic amphibians and reptilians which were found, namely, Aeromonas sp. (n = 29), Plesiomonas sp. (n = 7), Vibrio sp. (n = 12), Citrobacter sp. (n = 12), Enterobacter sp. (n = 11), Escherichia sp. (n = 22), Klebsiella sp. (n = 22), Edwardsiella sp. (n = 6), Hafnia sp. (n = 1), Proteus sp. (n = 19), Providencia sp. (n = 8), and Pseudomonas sp. (n = 4). In terms of antibiotic and heavy metal susceptibility testing, each isolate was tested against 12 antibiotics and 4 metals. There was a high incidence of resistance to cefoxitin (46.40 %), ampicillin (44.44 %), erythromycin (35.29 %), and a low incidence of resistance to gentamicin (6.53 %), kanamycin (8.49 %), chloramphenicol (9.15 %), and cefotaxime (10.45 %). The multiple antibiotic resistance index of each bacterial species indicated that bacteria from raised amphibians and reptiles have been exposed to tested antibiotics, with results ranging from 0 to 0.58. Most isolates showed tolerance to different concentrations of heavy metals, and minimal inhibition concentrations ranged from100 to >3,200 μg/mL. According to these results, a significant occurrence of bacteria in the internal organs of reptiles and amphibians, with a high incidence of resistance against antibiotics and heavy metals, may risk aquatic animals and the public health. These data appoint the importance of epidemiological surveillance and microbiological monitoring and reinforce the need to implement environment protection programs for amphibian and reptile species.

  20. From ratites to rats: the size of fleshy fruits shapes species' distributions and continental rainforest assembly.

    Science.gov (United States)

    Rossetto, Maurizio; Kooyman, Robert; Yap, Jia-Yee S; Laffan, Shawn W

    2015-12-07

    Seed dispersal is a key process in plant spatial dynamics. However, consistently applicable generalizations about dispersal across scales are mostly absent because of the constraints on measuring propagule dispersal distances for many species. Here, we focus on fleshy-fruited taxa, specifically taxa with large fleshy fruits and their dispersers across an entire continental rainforest biome. We compare species-level results of whole-chloroplast DNA analyses in sister taxa with large and small fruits, to regional plot-based samples (310 plots), and whole-continent patterns for the distribution of woody species with either large (more than 30 mm) or smaller fleshy fruits (1093 taxa). The pairwise genomic comparison found higher genetic distances between populations and between regions in the large-fruited species (Endiandra globosa), but higher overall diversity within the small-fruited species (Endiandra discolor). Floristic comparisons among plots confirmed lower numbers of large-fruited species in areas where more extreme rainforest contraction occurred, and re-colonization by small-fruited species readily dispersed by the available fauna. Species' distribution patterns showed that larger-fruited species had smaller geographical ranges than smaller-fruited species and locations with stable refugia (and high endemism) aligned with concentrations of large fleshy-fruited taxa, making them a potentially valuable conservation-planning indicator. © 2015 The Author(s).

  1. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History

    Science.gov (United States)

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support.

  2. Species distribution and introgressive hybridization of two Avicennia species from the Western Hemisphere unveiled by phylogeographic patterns.

    Science.gov (United States)

    Mori, Gustavo M; Zucchi, Maria I; Sampaio, Iracilda; Souza, Anete P

    2015-04-10

    Mangrove plants grow in the intertidal zone in tropical and subtropical regions worldwide. The global latitudinal distribution of the mangrove is mainly influenced by climatic and oceanographic features. Because of current climate changes, poleward range expansions have been reported for the major biogeographic regions of mangrove forests in the Western and Eastern Hemispheres. There is evidence that mangrove forests also responded similarly after the last glaciation by expanding their ranges. In this context, the use of genetic tools is an informative approach for understanding how historical processes and factors impact the distribution of mangrove species. We investigated the phylogeographic patterns of two Avicennia species, A. germinans and A. schaueriana, from the Western Hemisphere using nuclear and chloroplast DNA markers. Our results indicate that, although Avicennia bicolor, A. germinans and A. schaueriana are independent lineages, hybridization between A. schaueriana and A. germinans is a relevant evolutionary process. Our findings also reinforce the role of long-distance dispersal in widespread mangrove species such as A. germinans, for which we observed signs of transatlantic dispersal, a process that has, most likely, contributed to the breadth of the distribution of A. germinans. However, along the southern coast of South America, A. schaueriana is the only representative of the genus. The distribution patterns of A. germinans and A. schaueriana are explained by their different responses to past climate changes and by the unequal historical effectiveness of relative gene flow by propagules and pollen. We observed that A. bicolor, A. germinans and A. schaueriana are three evolutionary lineages that present historical and ongoing hybridization on the American continent. We also inferred a new evidence of transatlantic dispersal for A. germinans, which may have contributed to its widespread distribution. Despite the generally wider distribution of A

  3. Spatial structures of the environment and of dispersal impact species distribution in competitive metacommunities.

    Science.gov (United States)

    Ai, Dexiecuo; Gravel, Dominique; Chu, Chengjin; Wang, Gang

    2013-01-01

    The correspondence between species distribution and the environment depends on species' ability to track favorable environmental conditions (via dispersal) and to maintain competitive hierarchy against the constant influx of migrants (mass effect) and demographic stochasticity (ecological drift). Here we report a simulation study of the influence of landscape structure on species distribution. We consider lottery competition for space in a spatially heterogeneous environment, where the landscape is represented as a network of localities connected by dispersal. We quantified the contribution of neutrality and species sorting to their spatial distribution. We found that neutrality increases and the strength of species-sorting decreases with the centrality of a community in the landscape when the average dispersal among communities is low, whereas the opposite was found at elevated dispersal. We also found that the strength of species-sorting increases with environmental heterogeneity. Our results illustrate that spatial structure of the environment and of dispersal must be taken into account for understanding species distribution. We stress the importance of spatial geographic structure on the relative importance of niche vs. neutral processes in controlling community dynamics.

  4. Spatial structures of the environment and of dispersal impact species distribution in competitive metacommunities.

    Directory of Open Access Journals (Sweden)

    Dexiecuo Ai

    Full Text Available The correspondence between species distribution and the environment depends on species' ability to track favorable environmental conditions (via dispersal and to maintain competitive hierarchy against the constant influx of migrants (mass effect and demographic stochasticity (ecological drift. Here we report a simulation study of the influence of landscape structure on species distribution. We consider lottery competition for space in a spatially heterogeneous environment, where the landscape is represented as a network of localities connected by dispersal. We quantified the contribution of neutrality and species sorting to their spatial distribution. We found that neutrality increases and the strength of species-sorting decreases with the centrality of a community in the landscape when the average dispersal among communities is low, whereas the opposite was found at elevated dispersal. We also found that the strength of species-sorting increases with environmental heterogeneity. Our results illustrate that spatial structure of the environment and of dispersal must be taken into account for understanding species distribution. We stress the importance of spatial geographic structure on the relative importance of niche vs. neutral processes in controlling community dynamics.

  5. Ecophysiological Traits of Leaves of Three Marsilea Species Distributed in Different Geographical Regions

    Directory of Open Access Journals (Sweden)

    Tai-Chung Wu

    2011-11-01

    Full Text Available Marsilea, an amphibian fern genus (containing ca. 80 species characterized by their unusual leaves and reproductive structures, is distributed over the five continents. To investigate the adaptation traits of three Marsilea species (M. crenata, M. quadrifolia, and M. schelpiana, distributed in different geographic regions, to terrestrial conditions, we compared morphological features, optical properties and photosynthetic performance of leaflets of the three species grown in terrestrial environment. The results showed that leaflets of the three species had significant differences in some of the ecophysiogical traits. Among the three species, M. quadrifolia (distributed in temperate region where receiving low precipitation had the highest trichome density on its leaflet surface and the highest water use efficiency, M. schelpiana (mainly in southern Africa where accepting high level of solar irradiance had the tallest petiole and the highest leaf dissection index, total stomatal pore area index, PSII electron transport rate and photosaturated photosynthetic rate, M. crenata (mainly in southeastern Asia region where receiving high precipitation and with high humidity had the lowest leaf dissection index and water use efficiency. Accordingly, leaf characteristics of the three Marsilea species reflect the climate pattern of their habitats. The results also suggest that water availability and light intensity are two of the important factors contributing to the geographic distribution of the three species.

  6. Spatial distribution of the species of the genus Buenoa (Hemiptera: Notonectidae) in Tumaco (Narino, Colombia)

    International Nuclear Information System (INIS)

    Padilla Gil, Dora Nancy

    2014-01-01

    The work was carried in the marine agricola farm of the Municipality Tumaco, with the objective of studying the distribution of the species of the genus Buenoa in homogeneous environmental conditions regarding temperature, humidity, altitude and aquatic habitats of the freshwater and the others with different grade of conductivity and dedicated to the marine shrimp farming Litopenaeus vannamei (Boone, 1931). The studied lakes were four of freshwater and four with different conductivity, in the months of June to November 2010. The results showed heterogeneous distribution of the species of the genus Buenoa with major diversity in freshwater (5 species) and lower abundance; while in saltwater had lower diversity (4 species) and major abundance. Only Buenoa dactylis Padilla-Gil 2010 was found in both aquatic environments. It is discussed possible ecological implications than can influence this distribution pattern are discussed.

  7. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    Directory of Open Access Journals (Sweden)

    Guoyu Lan

    Full Text Available Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1 fourteen of the twenty tree species were negatively (or positively associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2 Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m which was lost at larger scales (10-30 m. (3 The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4 It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

  8. Distribution and ecology of pest fruit fly species in Asia and the Pacific

    International Nuclear Information System (INIS)

    Allwood, Allan; Vueti, Ema Tora

    2003-01-01

    Fruit flies belong to the very diverse family Tephritidae, which consists of over 4,500 species distributed in most temperate, sub-tropical and tropical countries. In Asia and the Pacific regions, most of the major pest species belong to two genera. Bactrocera and Dacus. Representatives of Ceratitis occur in southwest Western Australia and the Indian Ocean islands and Carpomya occur in the Indian sub-continent and in Mauritius and Reunion. In the Asian region, 180 species of Bactrocera and 30 species of Dacus have been recorded and in the Australasian and Oceanic region, there are 270 species of Bactrocera and 27 species of Dacus. The diversity of species progressively decreases as the plant/host diversity decreases from west in Indonesia and Papua New Guinea to east in the Polynesian Island countries. The major pest species in the Asian region belong to the dorsalis complex (B. carambolae, B. dorsalis, B. occipitalis, B. philippinensis, B. papayae and B. pyrifoliae) and include other species such as B. cucurbitae, B. zonata, B. latifrons, and others. In the Pacific region, Australia has 100 species of fruit flies. Many Pacific Island countries each have endemic species, several of which are major pests. The factors that impact on populations of fruit flies include host ranges, life cycles, mating and oviposition behavior, dispersal capacity, nutritional, moisture, temperature and light requirements, and competition within and between species. (author)

  9. Spatial distribution, Leishmania species and clinical traits of Cutaneous Leishmaniasis cases in the Colombian army.

    Science.gov (United States)

    Patino, Luz H; Mendez, Claudia; Rodriguez, Omaira; Romero, Yanira; Velandia, Daniel; Alvarado, Maria; Pérez, Julie; Duque, Maria Clara; Ramírez, Juan David

    2017-08-01

    In Colombia, the cutaneous leishmaniasis (CL) is the most common manifestation across the army personnel. Hence, it is mandatory to determine the species associated with the disease as well as the association with the clinical traits. A total of 273 samples of male patients with CL were included in the study and clinical data of the patients was studied. PCR and sequencing analyses (Cytb and HSP70 genes) were performed to identify the species and the intra-specific genetic variability. A georeferenced database was constructed to identify the spatial distribution of Leishmania species isolated. The identification of five species of Leishmania that circulate in the areas where army personnel are deployed is described. Predominant infecting Leishmania species corresponds to L. braziliensis (61.1%), followed by Leishmania panamensis (33.5%), with a high distribution of both species at geographical and municipal level. The species L. guyanensis, L. mexicana and L. lainsoni were also detected at lower frequency. We also showed the identification of different genotypes within L. braziliensis and L. panamensis. In conclusion, we identified the Leishmania species circulating in the areas where Colombian army personnel are deployed, as well as the high intra-specific genetic variability of L. braziliensis and L. panamensis and how these genotypes are distributed at the geographic level.

  10. Fish species composition, density-distribution patterns, and impingement during upwelling

    International Nuclear Information System (INIS)

    Spigarelli, S.A.; Sharma, R.K.

    1975-01-01

    The effects of cooling system intakes and discharges on Lake Michigan fishes are highly dependent on inshore species composition and spatial distribution which, in turn, are affected by natural hydrological conditions. Significant (5 to 10 C) short-term decreases in water temperature (due to upwelling) could cause cold shock in fish equilibrated to either ambient or plume temperatures; substantial changes in distribution due to avoidance or attraction responses; and resultant changes in susceptibility to impingement. The objectives of this study are to characterize the changes in fish species composition, density, and thermal distribution as a result of natural upwellings, and to relate these factors to intake and discharge effects. Day and night sampling was conducted in ambient (reference) and thermal plume waters near the Zion Nuclear Plant on four occasions between 17 July and 11 September 1975. Density-distribution patterns and species composition of fish were determined by means of gill nets, bottom trawls, seines, and a sonic fish locater

  11. Species distributions models in wildlife planning: agricultural policy and wildlife management in the great plains

    Science.gov (United States)

    Fontaine, Joseph J.; Jorgensen, Christopher; Stuber, Erica F.; Gruber, Lutz F.; Bishop, Andrew A.; Lusk, Jeffrey J.; Zach, Eric S.; Decker, Karie L.

    2017-01-01

    We know economic and social policy has implications for ecosystems at large, but the consequences for a given geographic area or specific wildlife population are more difficult to conceptualize and communicate. Species distribution models, which extrapolate species-habitat relationships across ecological scales, are capable of predicting population changes in distribution and abundance in response to management and policy, and thus, are an ideal means for facilitating proactive management within a larger policy framework. To illustrate the capabilities of species distribution modeling in scenario planning for wildlife populations, we projected an existing distribution model for ring-necked pheasants (Phasianus colchicus) onto a series of alternative future landscape scenarios for Nebraska, USA. Based on our scenarios, we qualitatively and quantitatively estimated the effects of agricultural policy decisions on pheasant populations across Nebraska, in specific management regions, and at wildlife management areas. 

  12. Mid-winter European dabbling duck distributions are not linked to species body mass

    DEFF Research Database (Denmark)

    Dalby, Lars; Delany, Simon; Fox, Anthony David

    are likely to play a major role in determining the wintering distribution of short- to medium-distance migratory bird species and its inter-annual variability. As avian thermoregulatory costs scale allometrically with body size, we predicted that the mean mid-winter temperature experienced by six species...... of dabbling ducks wintering in Western Europe would be negatively correlated with body mass. We found no evidence for such a relationship in a large-scale analysis testing for a link between temperature and dabbling duck distributions, suggesting that other factors such as those related to feeding ecology......In order to understand the current changes and to predict future changes in wintering dabbling duck (Anas sp.) distributions in response to climate change, it is important to understand how species distribute themselves on a continental scale in response to temperature. Thermoregulatory costs...

  13. Environmental niche divergence among three dune shrub sister species with parapatric distributions.

    Science.gov (United States)

    Chozas, Sergio; Chefaoui, Rosa M; Correia, Otília; Bonal, Raúl; Hortal, Joaquín

    2017-05-01

    The geographical distributions of species are constrained by their ecological requirements. The aim of this work was to analyse the effects of environmental conditions, historical events and biogeographical constraints on the diversification of the three species of the western Mediterranean shrub genus Stauracanthus , which have a parapatric distribution in the Iberian Peninsula. Ecological niche factor analysis and generalized linear models were used to measure the response of all Stauracanthus species to the environmental gradients and map their potential distributions in the Iberian Peninsula. The bioclimatic niche overlap between the three species was determined by using Schoener's index. The genetic differentiation of the Iberian and northern African populations of Stauracanthus species was characterized with GenalEx. The effects on genetic distances of the most important environmental drivers were assessed through Mantel tests and non-metric multidimensional scaling. The three Stauracanthus species show remarkably similar responses to climatic conditions. This supports the idea that all members of this recently diversified clade retain common adaptations to climate and consequently high levels of climatic niche overlap. This contrasts with the diverse edaphic requirements of Stauracanthus species. The populations of the S. genistoides-spectabilis clade grow on Miocene and Pliocene fine-textured sedimentary soils, whereas S. boivinii , the more genetically distant species, occurs on older and more coarse-textured sedimentary substrates. These patterns of diversification are largely consistent with a stochastic process of geographical range expansion and fragmentation coupled with niche evolution in the context of spatially complex environmental fluctuations. : The combined analysis of the distribution, realized environmental niche and phylogeographical relationships of parapatric species proposed in this work allows integration of the biogeographical

  14. Estimating the spatial and temporal distribution of species richness within Sequoia and Kings Canyon National Parks.

    Directory of Open Access Journals (Sweden)

    Steve Wathen

    Full Text Available Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofauna (reptiles and amphibians, and plants within Sequoia and Kings Canyon National Parks using only existing biological studies undertaken within the Parks and the Parks' long-term wildlife observation database. We used a rarefaction approach to model species richness for the four taxonomic groups and analyzed those groups by habitat type, elevation zone, and time period. We then mapped the spatial distributions of species richness values for the four taxonomic groups, as well as total species richness, for the Parks. We also estimated changes in species richness for birds, mammals, and herpetofauna since 1980. The modeled patterns of species richness either peaked at mid elevations (mammals, plants, and total species richness or declined consistently with increasing elevation (herpetofauna and birds. Plants reached maximum species richness values at much higher elevations than did vertebrate taxa, and non-flying mammals reached maximum species richness values at higher elevations than did birds. Alpine plant communities, including sagebrush, had higher species richness values than did subalpine plant communities located below them in elevation. These results are supported by other papers published in the scientific literature. Perhaps reflecting climate change: birds and herpetofauna displayed declines in species richness since 1980 at low and middle elevations and mammals displayed declines in species richness since 1980 at all elevations.

  15. Chemical composition and in vitro antimicrobial activity of the essential oils of two Helichrysum species from Tanzania.

    Science.gov (United States)

    Bougatsos, Christos; Ngassapa, Olipa; Runyoro, Deborah K B; Chinou, Ioanna B

    2004-01-01

    The chemical composition of the essential oils obtained from the aerial parts of Helichrysum cymosum and H. fulgidum, from Tanzania, were analyzed by GC and GC/MS. A total of sixty-five compounds, representing 92.4% and 88.2% of the two oils, respectively, were identified. trans-Caryophyllene, caryophyllene oxide, beta-pinene, p-cymene, spathulenol and beta-bourbonene were found to be the main components. Furthermore, the oils were tested against six gram (+/-) bacteria and three pathogenic fungi. It was found that the oil of H. fulgidum exhibited significant antimicrobial activity, while the oil of H. cymosum was not active at all.

  16. Coagulase-negative Staphylococcus species in bulk milk: Prevalence, distribution, and associated subgroup- and species-specific risk factors.

    Science.gov (United States)

    De Visscher, A; Piepers, S; Haesebrouck, F; Supré, K; De Vliegher, S

    2017-01-01

    Coagulase-negative staphylococci (CNS) have become the main pathogens causing bovine mastitis in recent years. A huge variation in species distribution among herds has been observed in several studies, emphasizing the need to identify subgroup- and species-specific herd-level factors to improve our understanding of the differences in ecological and epidemiological nature between species. The use of bulk milk samples enables the inclusion of a large(r) number of herds needed to identify herd-level risk factors and increases the likelihood of recovering enough isolates per species needed for conducting subgroup- and, eventually, species-specific analyses at the same time. This study aimed to describe the prevalence and distribution of CNS species in bulk milk samples and to identify associated subgroup- and species-specific herd-level factors. Ninety percent of all bulk milk samples yielded CNS. Staphylococcus equorum was the predominant species, followed by Staphylococcus haemolyticus and Staphylococcus epidermidis. A seasonal effect was observed for several CNS species. Bulk milk samples from herds with a loose-pack or a tiestall housing system were more likely to yield CNS species compared with herds with a freestall barn, except for S. epidermidis, Staphylococcus simulans, and Staphylococcus cohnii. In September, herds in which udders were clipped had lower odds of yielding Staphylococcus chromogenes, S. simulans, and Staphylococcus xylosus, the CNS species assumed to be most relevant for udder health, in their bulk milk than herds in which udder clipping was not practiced. Bulk milk of herds participating in a monthly veterinary udder health-monitoring program was more likely to yield these 3 CNS species. Herds always receiving their milk quality premium or predisinfecting teats before attachment of the milking cluster had lower odds of having S. equorum in their bulk milk. Herds not using a single dry cotton or paper towel for each cow during premilking udder

  17. Chemosymbiotic species from the Gulf of Cadiz (NE Atlantic: distribution, life styles and nutritional patterns

    Directory of Open Access Journals (Sweden)

    C. F. Rodrigues

    2013-04-01

    Full Text Available Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (δ13C, δ15N and δ34S and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata. Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin.

  18. Species distribution of kobs (Kobus kob) in the Shai Hills Resource Reserve: an exploratory analysis.

    Science.gov (United States)

    Antwi, Raymond Agyepong; Owusu, Erasmus Henaku; Attuquayefio, Daniel Korley

    2018-02-01

    The well-being of a species fundamentally rests on understanding its biology, home range, and distribution. The highly seasonal distribution of kobs poses conservation and management difficulties, particularly because of the capricious nature of the ever-changing ecological and vegetation dynamics of the ecosystem. Assessing the distribution of kobs and their associated vegetation provides insight into the vulnerability and conservation status of the species. Species distribution and habitat suitability maps were developed and created respectively for the management of kobs in the Shai Hills Resource Reserve. Kob presence data collected was analyzed using the spatial analyst and Hawth's tool in the ArcGIS software where the gradients of kob distribution within the protected area landscape were plotted and mapped. Seven environmental variables including location, land cover/use, slope/elevation, nearness to dams and rivers, temperature, and rainfall were considered to have effect on kob distribution pattern and as such used in the development of species distribution and habitat suitability maps. The results indicated that kobs in the Shai Hills Resource Reserve (SHRR) assume a clumped or contagious distribution pattern where individual kobs are aggregated in patches. Rainfall, temperature, nearness to dams and rivers, slope/elevation, and land cover/use had influence in kob distribution. Of all the cataloged habitats, 86, 13, and 1% were moderately suitable, suitable, and unsuitable, respectively. Long-term survival of species depends on adequately large areas of suitable habitats and opportunities for home range activities between such areas. As such, it is recommended that suitable habitats for kobs be dedicated and designated as conservation areas, especially areas along the western boundary.

  19. Historical change in fish species distribution: shifting reference conditions and global warming effects.

    Science.gov (United States)

    Pont, Didier; Logez, M; Carrel, G; Rogers, C; Haidvogl, G

    Species distributions models (SDM) that rely on estimated relationships between present environmental conditions and species presence-absence are widely used to forecast changes of species distributions caused by global warming but far less to reconstruct historical assemblages. By compiling historical fish data from the turn to the middle of the twentieth century in a similar way for several European catchments (Rhône, Danube), and using already published SDMs based on current observations, we: (1) tested the predictive accuracy of such models for past climatic conditions, (2) compared observed and expected cumulated historical species occurrences at sub-catchment level, and (3) compared the annual variability in the predictions within one sub-catchment (Salzach) under a future climate scenario to the long-term variability of occurrences reconstructed during an extended historical period (1800-2000). We finally discuss the potential of these SDMs to define a "reference condition", the possibility of a shift in baseline condition in relation with anthropogenic pressures, and past and future climate variability. The results of this study clearly highlight the potential of SDM to reconstruct the past composition of European fish assemblages and to analyze the historical ecological status of European rivers. Assessing the uncertainty associated with species distribution projections is of primary importance before evaluating and comparing the past and future distribution of species within a given catchment.

  20. Multi-scale approach for predicting fish species distributions across coral reef seascapes.

    Directory of Open Access Journals (Sweden)

    Simon J Pittman

    Full Text Available Two of the major limitations to effective management of coral reef ecosystems are a lack of information on the spatial distribution of marine species and a paucity of data on the interacting environmental variables that drive distributional patterns. Advances in marine remote sensing, together with the novel integration of landscape ecology and advanced niche modelling techniques provide an unprecedented opportunity to reliably model and map marine species distributions across many kilometres of coral reef ecosystems. We developed a multi-scale approach using three-dimensional seafloor morphology and across-shelf location to predict spatial distributions for five common Caribbean fish species. Seascape topography was quantified from high resolution bathymetry at five spatial scales (5-300 m radii surrounding fish survey sites. Model performance and map accuracy was assessed for two high performing machine-learning algorithms: Boosted Regression Trees (BRT and Maximum Entropy Species Distribution Modelling (MaxEnt. The three most important predictors were geographical location across the shelf, followed by a measure of topographic complexity. Predictor contribution differed among species, yet rarely changed across spatial scales. BRT provided 'outstanding' model predictions (AUC = >0.9 for three of five fish species. MaxEnt provided 'outstanding' model predictions for two of five species, with the remaining three models considered 'excellent' (AUC = 0.8-0.9. In contrast, MaxEnt spatial predictions were markedly more accurate (92% map accuracy than BRT (68% map accuracy. We demonstrate that reliable spatial predictions for a range of key fish species can be achieved by modelling the interaction between the geographical location across the shelf and the topographic heterogeneity of seafloor structure. This multi-scale, analytic approach is an important new cost-effective tool to accurately delineate essential fish habitat and support

  1. Species Distribution Modeling: Comparison of Fixed and Mixed Effects Models Using INLA

    Directory of Open Access Journals (Sweden)

    Lara Dutra Silva

    2017-12-01

    Full Text Available Invasive alien species are among the most important, least controlled, and least reversible of human impacts on the world’s ecosystems, with negative consequences affecting biodiversity and socioeconomic systems. Species distribution models have become a fundamental tool in assessing the potential spread of invasive species in face of their native counterparts. In this study we compared two different modeling techniques: (i fixed effects models accounting for the effect of ecogeographical variables (EGVs; and (ii mixed effects models including also a Gaussian random field (GRF to model spatial correlation (Matérn covariance function. To estimate the potential distribution of Pittosporum undulatum and Morella faya (respectively, invasive and native trees, we used geo-referenced data of their distribution in Pico and São Miguel islands (Azores and topographic, climatic and land use EGVs. Fixed effects models run with maximum likelihood or the INLA (Integrated Nested Laplace Approximation approach provided very similar results, even when reducing the size of the presences data set. The addition of the GRF increased model adjustment (lower Deviance Information Criterion, particularly for the less abundant tree, M. faya. However, the random field parameters were clearly affected by sample size and species distribution pattern. A high degree of spatial autocorrelation was found and should be taken into account when modeling species distribution.

  2. Distribution of silica species in cooling water system in nuclear power station

    International Nuclear Information System (INIS)

    Akiba, Kenichi; Onozuka, Teruo; Shindo, Manabu.

    1995-01-01

    Distribution of silica species was examined by spectrophotometric method based on the formation of molybdosilicic acid species. Ultra-microamounts of ionic (reactive) silica were determined by collection of silicomolybdenum blue compound on a nitrocellulose membrane filter. Total concentrations of silica including nonionic (polymer and colloidal) species were also determined after decomposition of unreactive silica in alkali solutions. Water in the nuclear reactor (Onagawa BWR No.1) contained high concentration of silica (∼600 ppb) and ionic silica was found to be predominant (∼90%). In condensate system, silica contents were of a lower level (2-6 ppb), but the ionic silica contents were comparable to others (20-60%). The silica species appear to be brought and accumulated in the reactor from the condensate system, and then the silica species change to ionic species under high pressure and high temperature. (author)

  3. Distribution of silica species in cooling water system in nuclear power station

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Kenichi [Tohoku Univ., Sendai (Japan). Inst. for Advanced Materials Processing; Onozuka, Teruo; Shindo, Manabu

    1995-12-01

    Distribution of silica species was examined by spectrophotometric method based on the formation of molybdosilicic acid species. Ultra-microamounts of ionic (reactive) silica were determined by collection of silicomolybdenum blue compound on a nitrocellulose membrane filter. Total concentrations of silica including nonionic (polymer and colloidal) species were also determined after decomposition of unreactive silica in alkali solutions. Water in the nuclear reactor (Onagawa BWR No.1) contained high concentration of silica ({approx}600 ppb) and ionic silica was found to be predominant ({approx}90%). In condensate system, silica contents were of a lower level (2-6 ppb), but the ionic silica contents were comparable to others (20-60%). The silica species appear to be brought and accumulated in the reactor from the condensate system, and then the silica species change to ionic species under high pressure and high temperature. (author).

  4. Species Abundance in a Forest Community in South China: A Case of Poisson Lognormal Distribution

    Institute of Scientific and Technical Information of China (English)

    Zuo-Yun YIN; Hai REN; Qian-Mei ZHANG; Shao-Lin PENG; Qin-Feng GUO; Guo-Yi ZHOU

    2005-01-01

    Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m×20 m, 5 m×5 m, and 1 m×1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal;(ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (σ andμ) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the σ and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/σ should be an alternative measure of diversity.

  5. Mesoscale distribution of dominant diatom species relative to the hydrographical field along the Antarctic Polar Front

    Science.gov (United States)

    Smetacek, Victor; Klaas, Christine; Menden-Deuer, Susanne; Rynearson, Tatiana A.

    The quantitative distribution of dominant phytoplankton species was mapped at high spatial resolution (15 km spacing) during a quasi-synoptic, mesoscale survey of hydrographical, chemical, pigment, and zooplankton fields carried out along the Antarctic Polar Front within a grid 140×130 km 2 during austral summer. A rapid assessment method for quantifying phytoplankton species by microscopy in concentrated samples on board enabled estimation of total biomass and that of dominant species at hourly sampling intervals. The biomass distribution pattern derived from this method was remarkably coherent and correlated very well with chlorophyll concentrations and the location of different water masses covered by the grid. A "background" chlorophyll concentration of 0.5 mg m -3 in the grid could be assigned to the uniformly distributed pico- and nanophytoplankton; all higher values (up to 2.0 mg m -3) were contributed by large diatoms. Three species complexes ( Chaetoceros atlanticus/dichaeta, Pseudo-nitzschia cf. Lineola, and Thalassiothrix antarctica) contributed about one-third each to the biomass. Although all species were found throughout the study area, distinct patterns in abundance emerged: The Thalassiothrix maximum was located north of the frontal jet, Chaetoceros biomass was highest along the jet, and Pseudo-nitzschia was the most uniformly distributed of the three taxa. Since the meridional pattern of biomass and species composition persisted for about 5 weeks, despite heavy grazing pressure of small copepods, we hypothesize that the dominant species reflect the highest degree of grazer protection in the assemblage. This is accomplished by large size, needle-shaped cells, and long spines armed with barbs. We suggest that these persistent species sequester the limiting nutrient—iron—from the assemblage of smaller, less-defended species that must hence have higher turn-over rates.

  6. Do abundance distributions and species aggregation correctly predict macroecological biodiversity patterns in tropical forests?

    Science.gov (United States)

    Wiegand, Thorsten; Lehmann, Sebastian; Huth, Andreas; Fortin, Marie‐Josée

    2016-01-01

    Abstract Aim It has been recently suggested that different ‘unified theories of biodiversity and biogeography’ can be characterized by three common ‘minimal sufficient rules’: (1) species abundance distributions follow a hollow curve, (2) species show intraspecific aggregation, and (3) species are independently placed with respect to other species. Here, we translate these qualitative rules into a quantitative framework and assess if these minimal rules are indeed sufficient to predict multiple macroecological biodiversity patterns simultaneously. Location Tropical forest plots in Barro Colorado Island (BCI), Panama, and in Sinharaja, Sri Lanka. Methods We assess the predictive power of the three rules using dynamic and spatial simulation models in combination with census data from the two forest plots. We use two different versions of the model: (1) a neutral model and (2) an extended model that allowed for species differences in dispersal distances. In a first step we derive model parameterizations that correctly represent the three minimal rules (i.e. the model quantitatively matches the observed species abundance distribution and the distribution of intraspecific aggregation). In a second step we applied the parameterized models to predict four additional spatial biodiversity patterns. Results Species‐specific dispersal was needed to quantitatively fulfil the three minimal rules. The model with species‐specific dispersal correctly predicted the species–area relationship, but failed to predict the distance decay, the relationship between species abundances and aggregations, and the distribution of a spatial co‐occurrence index of all abundant species pairs. These results were consistent over the two forest plots. Main conclusions The three ‘minimal sufficient’ rules only provide an incomplete approximation of the stochastic spatial geometry of biodiversity in tropical forests. The assumption of independent interspecific placements is most

  7. Evaluation of Antimicrobial Efficiency of New Polymers Comprised by Covalently Attached and/or Electrostatically Bound Bacteriostatic Species, Based on Quaternary Ammonium Compounds.

    Science.gov (United States)

    Kougia, Efstathia; Tselepi, Maria; Vasilopoulos, Gavriil; Lainioti, Georgia Ch; Koromilas, Nikos D; Druvari, Denisa; Bokias, Georgios; Vantarakis, Apostolos; Kallitsis, Joannis K

    2015-12-01

    In the present work a detailed study of new bacteriostatic copolymers with quaternized ammonium groups introduced in the polymer chain through covalent attachment or electrostatic interaction, was performed. Different copolymers have been considered since beside the active species, the hydrophobic/hydrophilic nature of the co-monomer was also evaluated in the case of covalently attached bacteriostatic groups, aiming at achieving permanent antibacterial activity. Homopolymers with quaternized ammonium/phosphonium groups were also tested for comparison reasons. The antimicrobial activity of the synthesized polymers after 3 and 24 h of exposure at 4 and 22 °C was investigated on cultures of Gram-negative (P. aeruginosa, E. coli) and Gram-positive (S. aureus, E. faecalis) bacteria. It was found that the combination of the hydrophilic monomer acrylic acid (AA), at low contents, with the covalently attached bacteriostatic group vinyl benzyl dimethylhexadecylammonium chloride (VBCHAM) in the copolymer P(AA-co-VBCHAM88), resulted in a high bacteriostatic activity against P. aeruginosa and E. faecalis (6 log reduction in certain cases). Moreover, the combination of covalently attached VBCHAM units with electrostatically bound cetyltrimethylammonium 4-styrene sulfonate (SSAmC16) units in the P(SSAmC16-co-VBCHAMx) copolymers led to efficient antimicrobial materials, especially against Gram-positive bacteria, where a log reduction between 4.9 and 6.2 was verified. These materials remain remarkably efficient even when they are incorporated in polysulfone membranes.

  8. Using species abundance distribution models and diversity indices for biogeographical analyses

    Science.gov (United States)

    Fattorini, Simone; Rigal, François; Cardoso, Pedro; Borges, Paulo A. V.

    2016-01-01

    We examine whether Species Abundance Distribution models (SADs) and diversity indices can describe how species colonization status influences species community assembly on oceanic islands. Our hypothesis is that, because of the lack of source-sink dynamics at the archipelago scale, Single Island Endemics (SIEs), i.e. endemic species restricted to only one island, should be represented by few rare species and consequently have abundance patterns that differ from those of more widespread species. To test our hypothesis, we used arthropod data from the Azorean archipelago (North Atlantic). We divided the species into three colonization categories: SIEs, archipelagic endemics (AZEs, present in at least two islands) and native non-endemics (NATs). For each category, we modelled rank-abundance plots using both the geometric series and the Gambin model, a measure of distributional amplitude. We also calculated Shannon entropy and Buzas and Gibson's evenness. We show that the slopes of the regression lines modelling SADs were significantly higher for SIEs, which indicates a relative predominance of a few highly abundant species and a lack of rare species, which also depresses diversity indices. This may be a consequence of two factors: (i) some forest specialist SIEs may be at advantage over other, less adapted species; (ii) the entire populations of SIEs are by definition concentrated on a single island, without possibility for inter-island source-sink dynamics; hence all populations must have a minimum number of individuals to survive natural, often unpredictable, fluctuations. These findings are supported by higher values of the α parameter of the Gambin mode for SIEs. In contrast, AZEs and NATs had lower regression slopes, lower α but higher diversity indices, resulting from their widespread distribution over several islands. We conclude that these differences in the SAD models and diversity indices demonstrate that the study of these metrics is useful for

  9. Vertical distribution and migration of euphausiid species in the Red Sea

    KAUST Repository

    Wiebe, Peter H.

    2016-06-01

    We addressed how the extreme environmental conditions of the Red Sea impact or alter patterns of vertical distribution and vertical migration of five euphausiid species that are known from other oceans. Euphausia diomedeae was abundant and performed diel vertical migration (DVM) from >200 m in daytime to <100 m at night, similar to its pattern in other ocean regions. Euphausia sibogae and Euphausia sanzoi also showed consistent patterns of DVM across their ranges in the Red Sea and elsewhere. Two species, Stylocheiron affine and Stylocheiron abbreviatum, did not exhibit DVM. DNA barcode sequences for mitochondrial cytochrome oxidase I (COI) were used to confirm species identifications for four species (no previous barcode data exist for E. sanzoi). COI sequence differences averaged 2.8% (SD 3.1%) within species and 16.6% (SD 0.7%) between species, similar to previous studies of euphausiids. Red Sea specimens of S. affine matched morphological descriptions of a western equatorial form and differed 14% from Atlantic and Pacific specimens, suggesting possible cryptic species-level variation within this taxon. Widely distributed species of zooplankton may exhibit broad tolerance ranges for key environmental variables, and have considerable potential to adapt to variable and changing conditions across their geographic range.

  10. Species distribution models and ecological suitability analysis for potential tick vectors of lyme disease in Mexico.

    Science.gov (United States)

    Illoldi-Rangel, Patricia; Rivaldi, Chissa-Louise; Sissel, Blake; Trout Fryxell, Rebecca; Gordillo-Pérez, Guadalupe; Rodríguez-Moreno, Angel; Williamson, Phillip; Montiel-Parra, Griselda; Sánchez-Cordero, Víctor; Sarkar, Sahotra

    2012-01-01

    Species distribution models were constructed for ten Ixodes species and Amblyomma cajennense for a region including Mexico and Texas. The model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. For Mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. There was spatial nonconcordance between the distributions of Amblyomma cajennense and the Ixodes group with the former restricted to lowlands and mainly the eastern coast of Mexico and the latter to montane regions with lower temperature. The risk of Lyme disease is, therefore, mainly present in the highlands where some Ixodes species are known vectors; if Amblyomma cajennense turns out to be a competent vector, the area of risk also extends to the lowlands and the east coast.

  11. Species distribution modeling based on the automated identification of citizen observations.

    Science.gov (United States)

    Botella, Christophe; Joly, Alexis; Bonnet, Pierre; Monestiez, Pascal; Munoz, François

    2018-02-01

    A species distribution model computed with automatically identified plant observations was developed and evaluated to contribute to future ecological studies. We used deep learning techniques to automatically identify opportunistic plant observations made by citizens through a popular mobile application. We compared species distribution modeling of invasive alien plants based on these data to inventories made by experts. The trained models have a reasonable predictive effectiveness for some species, but they are biased by the massive presence of cultivated specimens. The method proposed here allows for fine-grained and regular monitoring of some species of interest based on opportunistic observations. More in-depth investigation of the typology of the observations and the sampling bias should help improve the approach in the future.

  12. Species Distribution Models and Ecological Suitability Analysis for Potential Tick Vectors of Lyme Disease in Mexico

    Directory of Open Access Journals (Sweden)

    Patricia Illoldi-Rangel

    2012-01-01

    Full Text Available Species distribution models were constructed for ten Ixodes species and Amblyomma cajennense for a region including Mexico and Texas. The model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. For Mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. There was spatial nonconcordance between the distributions of Amblyomma cajennense and the Ixodes group with the former restricted to lowlands and mainly the eastern coast of Mexico and the latter to montane regions with lower temperature. The risk of Lyme disease is, therefore, mainly present in the highlands where some Ixodes species are known vectors; if Amblyomma cajennense turns out to be a competent vector, the area of risk also extends to the lowlands and the east coast.

  13. What are the most crucial soil factors for predicting the distribution of alpine plant species?

    Science.gov (United States)

    Buri, A.; Pinto-Figueroa, E.; Yashiro, E.; Guisan, A.

    2017-12-01

    Nowadays the use of species distribution models (SDM) is common to predict in space and time the distribution of organisms living in the critical zone. The realized environmental niche concept behind the development of SDM imply that many environmental factors must be accounted for simultaneously to predict species distributions. Climatic and topographic factors are often primary included, whereas soil factors are frequently neglected, mainly due to the paucity of soil information available spatially and temporally. Furthermore, among existing studies, most included soil pH only, or few other soil parameters. In this study we aimed at identifying what are the most crucial soil factors for explaining alpine plant distributions and, among those identified, which ones further improve the predictive power of plant SDMs. To test the relative importance of the soil factors, we performed plant SDMs using as predictors 52 measured soil properties of various types such as organic/inorganic compounds, chemical/physical properties, water related variables, mineral composition or grain size distribution. We added them separately to a standard set of topo-climatic predictors (temperature, slope, solar radiation and topographic position). We used ensemble forecasting techniques combining together several predictive algorithms to model the distribution of 116 plant species over 250 sites in the Swiss Alps. We recorded the variable importance for each model and compared the quality of the models including different soil proprieties (one at a time) as predictors to models having only topo-climatic variables as predictors. Results show that 46% of the soil proprieties tested become the second most important variable, after air temperature, to explain spatial distribution of alpine plants species. Moreover, we also assessed that addition of certain soil factors, such as bulk soil water density, could improve over 80% the quality of some plant species models. We confirm that soil p

  14. Characterization of coagulase-negative staphylococcus species from cows' milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips.

    Science.gov (United States)

    Piessens, V; De Vliegher, S; Verbist, B; Braem, G; Van Nuffel, A; De Vuyst, L; Heyndrickx, M; Van Coillie, E

    2012-12-01

    The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess specific characteristics that promote colonization of the udder. Virulence markers associated with biofilm formation, antimicrobial resistance, and biocide tolerance were compared between typically contagious CNS species (Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus simulans) and those rarely causing IMI (Staphylococcus sciuri, Staphylococcus equorum, and others) to find possible associations with pathogenicity. Coagulase-negative staphylococci isolates (n=366) belonging to 22 different species were analyzed by PCR for the presence of the biofilm-associated genes bap and icaA, and the methicillin resistance gene mecA. A selection of 82 isolates was additionally tested for their susceptibility to 5 antibiotics and 2 commercial teat dip products. Minimum inhibitory concentrations of antimicrobials were determined by Etest (AB bioMérieux, Marcy l'Etoile, France), and a microdilution method was optimized to determine minimum biocidal concentrations of teat dips. The bap, icaA, and mecA genes were detected significantly more in isolates from CNS species typically living in the cows' environment than in isolates from IMI-causing species. Antimicrobial resistance was mainly against erythromycin (23%) or oxacillin (16%), and was detected more often in the environmental species. The isolates least susceptible to the teat dips belonged to the IMI-causing species Staph. chromogenes and Staph. simulans. We concluded that carriage of biofilm genes and antimicrobial resistance were not associated with the ability to colonize the mammary gland because free-living CNS species constituted a more significant reservoir of biofilm and resistance determinants than did IMI-causing species. In contrast, increased tolerance to biocides may favor the establishment of

  15. Cyclovirus CyCV-VN species distribution is not limited to Vietnam and extends to Africa.

    Science.gov (United States)

    Garigliany, Mutien-Marie; Hagen, Ralf Matthias; Frickmann, Hagen; May, Jürgen; Schwarz, Norbert Georg; Perse, Amanda; Jöst, Hanna; Börstler, Jessica; Shahhosseini, Nariman; Desmecht, Daniel; Mbunkah, Herbert Afegenwi; Daniel, Achukwi Mbunkah; Kingsley, Manchang Tanyi; Campos, Renata de Mendonca; de Paula, Vanessa Salete; Randriamampionona, Njary; Poppert, Sven; Tannich, Egbert; Rakotozandrindrainy, Raphael; Cadar, Daniel; Schmidt-Chanasit, Jonas

    2014-12-18

    Cycloviruses, small ssDNA viruses of the Circoviridae family, have been identified in the cerebrospinal fluid from symptomatic human patients. One of these species, cyclovirus-Vietnam (CyCV-VN), was shown to be restricted to central and southern Vietnam. Here we report the detection of CyCV-VN species in stool samples from pigs and humans from Africa, far beyond their supposed limited geographic distribution.

  16. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Science.gov (United States)

    Espinoza, Mario; Cappo, Mike; Heupel, Michelle R; Tobin, Andrew J; Simpfendorfer, Colin A

    2014-01-01

    Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.

  17. Checklist of American sand flies (Diptera, Psychodidae, Phlebotominae: genera, species, and their distribution

    Directory of Open Access Journals (Sweden)

    Paloma Helena Fernandes Shimabukuro

    2017-03-01

    Full Text Available Phlebotomine sand flies are dipteran insects of medical importance because many species are involved in the transmission of pathogens between human and non-human animals. A total of 530 American species of sand flies is presented in an updated checklist, along with their author(s and year of publication using the classification by Galati (1995, 2003. Distribution by country is also provided.

  18. Differences in Crossover Frequency and Distribution among Three Sibling Species of Drosophila

    OpenAIRE

    True, J. R.; Mercer, J. M.; Laurie, C. C.

    1996-01-01

    Comparisons of the genetic and cytogenetic maps of three sibling species of Drosophila reveal marked differences in the frequency and cumulative distribution of crossovers during meiosis. The maps for two of these species, Drosophila melanogaster and D. simulans, have previously been described, while this report presents new map data for D. mauritiana, obtained using a set of P element markers. A genetic map covering nearly the entire genome was constructed by estimating the recombination fra...

  19. Spatial distribution of seeds and seedlings of two tropical tree species: Is there correspondence between patterns?

    International Nuclear Information System (INIS)

    Parrado Rosselli, Angela

    2007-01-01

    The spatial patterns of seed and seedling distribution relative to parent trees (seed and seedling shadow, respectively) were studied for Dacryodes chimantensis (Burseraceae) and Brosimum utile (Moraceae), two common tree species of terra firme forests of Colombian Amazonia. The general objective was to assess whether the patterns imposed by seed dispersal change or persist in subsequent life stages occurring during the transition from seeds/saplings to adult stages. Seed and seedling shadows on the ground were characterized for each tree species along four 50-m radial transects from the base of the parent tree. Causes of seed and seedling predation as a function of distance to the parent tree were determined, as well as the spatial consistency between life stages. Results showed that seed density of both Dacryodes and Brosimum declined leptokurtically with distance, and it was skewed towards the parent tree. However, seed density was more skewed and leptokurtic in Dacryodes than in Brosimum. The overall trend was maintained in the seedling stage of both species and was positively correlated with the distribution patterns of seeds. Seed and seedling predation were positively correlated with density and negatively correlated with the distance from the parent tree. Factors that could be generating the high consistency between the spatial patterns of seed and seedling distribution are discussed, as well as its implications in the population structure of both species and the debate on the factors that influence the spatial distribution of plant species in tropical rain forests.

  20. Species distribution models for a migratory bird based on citizen science and satellite tracking data

    Directory of Open Access Journals (Sweden)

    Christopher L. Coxen

    2017-07-01

    Full Text Available Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1 satellite tracked birds and 2 observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4, and high overlap between suitability scores (I statistic 0.786 and suitable habitat patches (relative rank 0.639. Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

  1. Species distribution models for a migratory bird based on citizen science and satellite tracking data

    Science.gov (United States)

    Coxen, Christopher L.; Frey, Jennifer K.; Carleton, Scott A.; Collins, Daniel P.

    2017-01-01

    Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata) species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1) satellite tracked birds and 2) observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4), and high overlap between suitability scores (I statistic 0.786) and suitable habitat patches (relative rank 0.639). Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

  2. The effects of model and data complexity on predictions from species distributions models

    DEFF Research Database (Denmark)

    García-Callejas, David; Bastos, Miguel

    2016-01-01

    How complex does a model need to be to provide useful predictions is a matter of continuous debate across environmental sciences. In the species distributions modelling literature, studies have demonstrated that more complex models tend to provide better fits. However, studies have also shown...... that predictive performance does not always increase with complexity. Testing of species distributions models is challenging because independent data for testing are often lacking, but a more general problem is that model complexity has never been formally described in such studies. Here, we systematically...

  3. Ice age distriutions of European small mammals: insights from species distribution modelling

    DEFF Research Database (Denmark)

    Fløjgaard, Camilla; Normand, Signe; Skov, Flemming

    2009-01-01

    limits corresponding to the limits of temperate or boreal forest or arctic tundra were used in the analysis. We developed predictive distribution models based on the species present-day European distributions and validated these against their present-day Siberian ranges. The models with the best...... lemmus and Microtus oeconomus), suitable climate was predicted from the Atlantic coast eastward across central Europe and into Russia. Main conclusions. Our results support the idea of more northerly refuge areas in Europe, indicating that boreal species would have found suitable living conditions over...

  4. Predicting the geographical distribution of two invasive termite species from occurrence data.

    Science.gov (United States)

    Tonini, Francesco; Divino, Fabio; Lasinio, Giovanna Jona; Hochmair, Hartwig H; Scheffrahn, Rudolf H

    2014-10-01

    Predicting the potential habitat of species under both current and future climate change scenarios is crucial for monitoring invasive species and understanding a species' response to different environmental conditions. Frequently, the only data available on a species is the location of its occurrence (presence-only data). Using occurrence records only, two models were used to predict the geographical distribution of two destructive invasive termite species, Coptotermes gestroi (Wasmann) and Coptotermes formosanus Shiraki. The first model uses a Bayesian linear logistic regression approach adjusted for presence-only data while the second one is the widely used maximum entropy approach (Maxent). Results show that the predicted distributions of both C. gestroi and C. formosanus are strongly linked to urban development. The impact of future scenarios such as climate warming and population growth on the biotic distribution of both termite species was also assessed. Future climate warming seems to affect their projected probability of presence to a lesser extent than population growth. The Bayesian logistic approach outperformed Maxent consistently in all models according to evaluation criteria such as model sensitivity and ecological realism. The importance of further studies for an explicit treatment of residual spatial autocorrelation and a more comprehensive comparison between both statistical approaches is suggested.

  5. Species Distribution Modelling: Contrasting presence-only models with plot abundance data.

    Science.gov (United States)

    Gomes, Vitor H F; IJff, Stéphanie D; Raes, Niels; Amaral, Iêda Leão; Salomão, Rafael P; de Souza Coelho, Luiz; de Almeida Matos, Francisca Dionízia; Castilho, Carolina V; de Andrade Lima Filho, Diogenes; López, Dairon Cárdenas; Guevara, Juan Ernesto; Magnusson, William E; Phillips, Oliver L; Wittmann, Florian; de Jesus Veiga Carim, Marcelo; Martins, Maria Pires; Irume, Mariana Victória; Sabatier, Daniel; Molino, Jean-François; Bánki, Olaf S; da Silva Guimarães, José Renan; Pitman, Nigel C A; Piedade, Maria Teresa Fernandez; Mendoza, Abel Monteagudo; Luize, Bruno Garcia; Venticinque, Eduardo Martins; de Leão Novo, Evlyn Márcia Moraes; Vargas, Percy Núñez; Silva, Thiago Sanna Freire; Manzatto, Angelo Gilberto; Terborgh, John; Reis, Neidiane Farias Costa; Montero, Juan Carlos; Casula, Katia Regina; Marimon, Beatriz S; Marimon, Ben-Hur; Coronado, Euridice N Honorio; Feldpausch, Ted R; Duque, Alvaro; Zartman, Charles Eugene; Arboleda, Nicolás Castaño; Killeen, Timothy J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Schöngart, Jochen; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Laurance, William F; Camargo, José Luís; Demarchi, Layon O; Laurance, Susan G W; de Sousa Farias, Emanuelle; Nascimento, Henrique Eduardo Mendonça; Revilla, Juan David Cardenas; Quaresma, Adriano; Costa, Flavia R C; Vieira, Ima Célia Guimarães; Cintra, Bruno Barçante Ladvocat; Castellanos, Hernán; Brienen, Roel; Stevenson, Pablo R; Feitosa, Yuri; Duivenvoorden, Joost F; Aymard C, Gerardo A; Mogollón, Hugo F; Targhetta, Natalia; Comiskey, James A; Vicentini, Alberto; Lopes, Aline; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Emilio, Thaise; Alonso, Alfonso; Neill, David; Dallmeier, Francisco; Ferreira, Leandro Valle; Araujo-Murakami, Alejandro; Praia, Daniel; do Amaral, Dário Dantas; Carvalho, Fernanda Antunes; de Souza, Fernanda Coelho; Feeley, Kenneth; Arroyo, Luzmila; Pansonato, Marcelo Petratti; Gribel, Rogerio; Villa, Boris; Licona, Juan Carlos; Fine, Paul V A; Cerón, Carlos; Baraloto, Chris; Jimenez, Eliana M; Stropp, Juliana; Engel, Julien; Silveira, Marcos; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Maas, Paul; Thomas-Caesar, Raquel; Henkel, Terry W; Daly, Doug; Paredes, Marcos Ríos; Baker, Tim R; Fuentes, Alfredo; Peres, Carlos A; Chave, Jerome; Pena, Jose Luis Marcelo; Dexter, Kyle G; Silman, Miles R; Jørgensen, Peter Møller; Pennington, Toby; Di Fiore, Anthony; Valverde, Fernando Cornejo; Phillips, Juan Fernando; Rivas-Torres, Gonzalo; von Hildebrand, Patricio; van Andel, Tinde R; Ruschel, Ademir R; Prieto, Adriana; Rudas, Agustín; Hoffman, Bruce; Vela, César I A; Barbosa, Edelcilio Marques; Zent, Egleé L; Gonzales, George Pepe Gallardo; Doza, Hilda Paulette Dávila; de Andrade Miranda, Ires Paula; Guillaumet, Jean-Louis; Pinto, Linder Felipe Mozombite; de Matos Bonates, Luiz Carlos; Silva, Natalino; Gómez, Ricardo Zárate; Zent, Stanford; Gonzales, Therany; Vos, Vincent A; Malhi, Yadvinder; Oliveira, Alexandre A; Cano, Angela; Albuquerque, Bianca Weiss; Vriesendorp, Corine; Correa, Diego Felipe; Torre, Emilio Vilanova; van der Heijden, Geertje; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Young, Kenneth R; Rocha, Maira; Nascimento, Marcelo Trindade; Medina, Maria Natalia Umaña; Tirado, Milton; Wang, Ophelia; Sierra, Rodrigo; Torres-Lezama, Armando; Mendoza, Casimiro; Ferreira, Cid; Baider, Cláudia; Villarroel, Daniel; Balslev, Henrik; Mesones, Italo; Giraldo, Ligia Estela Urrego; Casas, Luisa Fernanda; Reategui, Manuel Augusto Ahuite; Linares-Palomino, Reynaldo; Zagt, Roderick; Cárdenas, Sasha; Farfan-Rios, William; Sampaio, Adeilza Felipe; Pauletto, Daniela; Sandoval, Elvis H Valderrama; Arevalo, Freddy Ramirez; Huamantupa-Chuquimaco, Isau; Garcia-Cabrera, Karina; Hernandez, Lionel; Gamarra, Luis Valenzuela; Alexiades, Miguel N; Pansini, Susamar; Cuenca, Walter Palacios; Milliken, William; Ricardo, Joana; Lopez-Gonzalez, Gabriela; Pos, Edwin; Ter Steege, Hans

    2018-01-17

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species' area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.

  6. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Directory of Open Access Journals (Sweden)

    Kari T Ryder Wilkie

    2010-10-01

    Full Text Available Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this

  7. Prevalence and antimicrobial resistance of Campylobacter species isolated from raw camel, beef, lamb, and goat meat in Iran.

    Science.gov (United States)

    Rahimi, Ebrahim; Ameri, Mehrdad; Kazemeini, Hamid Reza

    2010-04-01

    Campylobacter spp. are one of the most common causes of acute bacterial gastroenteritis in human beings which are transmitted mostly via food originating from animals. This study was conducted to determine the prevalence and antimicrobial resistance of Campylobacter spp. isolated from retail raw meats in Iran. From June 2008 to June 2009, a total of 722 raw meat samples from camel (n = 107), beef (n = 190), lamb (n = 225), and goat (n = 180) were purchased from randomly selected retail outlets in Isfahan and Yazd, Iran, and were evaluated for the presence of Campylobacter spp. In this study, 50 of the 722 meat samples (6.9%) were contaminated with Campylobacter spp. The highest prevalence of Campylobacter spp. was found in lamb meat (12.0%), followed by goat meat (9.4%), beef meat (2.4%), and camel meat (0.9%). The most prevalent Campylobacter spp. isolated from the meat samples was Campylobacter jejuni (84.0%); the remaining isolates were Campylobacter coli (16.0%). Susceptibilities of 50 Campylobacter isolates were determined for 10 antimicrobial drugs using the disk-diffusion assay. Resistance to tetracycline was the most common finding (68.0%), followed by resistance to ciprofloxacin (46.0%) and nalidixic acid (40.0%). All of the isolates were susceptible to erythromycin, gentamicin, and chloramphenicol. Significantly higher prevalence rates of Campylobacter spp. (p meat samples taken in spring (20.0%) and summer (18.9%). To our knowledge, this study is the first report of the isolation of Campylobacter spp. from raw camel, lamb, and goat meat in Iran.

  8. Are range-size distributions consistent with species-level heritability?

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Gotelli, Nicholas; Rahbek, Carsten

    2012-01-01

    The concept of species-level heritability is widely contested. Because it is most likely to apply to emergent, species-level traits, one of the central discussions has focused on the potential heritability of geographic range size. However, a central argument against range-size heritability has...... been that it is not compatible with the observed shape of present-day species range-size distributions (SRDs), a claim that has never been tested. To assess this claim, we used forward simulation of range-size evolution in clades with varying degrees of range-size heritability, and compared the output...

  9. Ferromanganese nodule fauna in the Tropical North Pacific Ocean: Species richness, faunal cover and spatial distribution

    Science.gov (United States)

    Veillette, Julie; Sarrazin, Jozée; Gooday, Andrew J.; Galéron, Joëlle; Caprais, Jean-Claude; Vangriesheim, Annick; Étoubleau, Joël; Christian, James R.; Kim Juniper, S.

    2007-11-01

    The poorly known ferromanganese nodule fauna is a widespread hard substratum community in the deep sea that will be considerably impacted by large-scale nodule mining operations. The objective of this study was to analyze the spatial distribution of the fauna attached to nodules in the Clarion-Clipperton Fracture Zone at two scales; a regional scale that includes the east (14°N, 130°W) and the west (9°N, 150°W) zones and a local scale in which different geological facies (A, B, C and west) are recognizable. The fauna associated with 235 nodules was quantitatively described: 104 nodules from the east zone (15 of facies A, 50 of facies B and 39 of facies C) and 131 nodules from the west zone. Percent cover was used to quantify the extent of colonization at the time of sampling, for 42 species out of the 62 live species observed. Fauna covered up to 18% of exposed nodule surface with an average of about 3%. While species richness increased with exposed nodule surface, both at the regional and at the facies scales (except for facies A), total species density decreased (again except for facies A). When all nodules were included in the statistical analysis, there was no relation between faunal cover and exposed nodule surface. Nevertheless, faunal cover did decrease with exposed nodule surface for the east zone in general and for both facies B and C in particular. Species distributions among facies were significantly different but explained only a very small portion of the variance (˜5%). We identified two groups of associated species: a first group of two species and a second group of six species. The other species (34) were independently distributed, suggesting that species interactions play only a minor role in the spatial distribution of nodule fauna. The flux of particulate organic carbon to the bottom is the only major environmental factor considered to vary between the two zones within this study. We conclude that the higher species richness and higher

  10. Hylid frogs from Mount Ayanganna, Guyana: new species, redescriptions, and distributional records

    Directory of Open Access Journals (Sweden)

    Ross D. MacCulloch

    2005-10-01

    Full Text Available A new species of Osteocephalus, one species of Hyla, three species of Hypsiboas and one of Myersiohyla were collected on Mount Ayanganna, a sandstone Guiana Shield tepui. Hyla warreni, Hypsiboas roraima, H. sibleszi, Myersiohyla kanaima and the new Osteocephalus were collected in high-tepui forest at 1500 m elevation, while Hypsiboas lemai, H. roraima and M. kanaima were also collected in lower montane forest at 870 m. Supplementary descriptions of adults of all species of Hyla, Hypsiboas and Myersiohyla based on the newly collected specimens are provided. Tadpoles of M. kanaima are described. The specimens from Ayanganna represent significant distributional records for several species. This is the first record of Osteocephalus as a member of the Guiana Shield high-tepui herpetofauna.

  11. Addressing potential local adaptation in species distribution models: implications for conservation under climate change

    Science.gov (United States)

    Hällfors, Maria Helena; Liao, Jishan; Dzurisin, Jason D. K.; Grundel, Ralph; Hyvärinen, Marko; Towle, Kevin; Wu, Grace C.; Hellmann, Jessica J.

    2016-01-01

    Species distribution models (SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs to treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account, may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted, however. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate MaxEnt models, one considering the species as a single population and two of disjunct populations. PCA analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species versus population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered.

  12. Predicting geographic distributions of Phacellodomus species (Aves: Furnariidae in South America based on ecological niche modeling

    Directory of Open Access Journals (Sweden)

    Maria da Salete Gurgel Costa

    2014-08-01

    Full Text Available Phacellodomus Reichenbach, 1853, comprises nine species of Furnariids that occur in South America in open and generally dry areas. This study estimated the geographic distributions of Phacellodomus species in South America by ecological niche modeling. Applying maximum entropy method, models were produced for eight species based on six climatic variables and 949 occurrence records. Since highest climatic suitability for Phacellodomus species has been estimated in open and dry areas, the Amazon rainforest areas are not very suitable for these species. Annual precipitation and minimum temperature of the coldest month are the variables that most influence the models. Phacellodomus species occurred in 35 ecoregions of South America. Chaco and Uruguayan savannas were the ecoregions with the highest number of species. Despite the overall connection of Phacellodomus species with dry areas, species such as P. ruber, P. rufifrons, P. ferrugineigula and P. erythrophthalmus occurred in wet forests and wetland ecoregions.

  13. Distribution of 10 periodontal bacterial species in children and adolescents over a 7-year period.

    Science.gov (United States)

    Nakano, K; Miyamoto, E; Tamura, K; Nemoto, H; Fujita, K; Nomura, R; Ooshima, T

    2008-10-01

    There is scant information available regarding the distribution of periodontal bacterial species in children and adolescents over an extended period. The purpose of this study was to compare bacterial profiles in the same individuals over a period of 7 years. Twenty-six children and adolescents from whom dental plaque and saliva specimens were obtained during both the first (1999-2000) and second (2006-2007) periods, were analyzed. Bacterial DNA was extracted from each specimen and the presence of 10 periodontal bacterial species was determined using a PCR method, with a focus on the red complex species of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Subjects with red complex species in saliva specimens obtained during the second collection possessed a significantly higher number of total bacterial species than those without. The detection rate of the red complex species in the second collection period samples was significantly greater in subjects who had two or more species detected in samples taken during the first collection compared with the other subjects. Subjects possessing red complex species may be at possible risk for infection with a high number of periodontal bacterial species during adolescent and younger adult years.

  14. Distribution, feeding and ecomorphology of four species of Auchenipteridae (Teleostei: Siluriformes in Eastern Amazonia, Brazil

    Directory of Open Access Journals (Sweden)

    Tiago M. S. Freitas

    Full Text Available ABSTRACT Fish exhibit morphological, physiological and behavioral specializations which enable them to display different ways to explore the environments and resources. Thus, the aim of this study was to verify how four Auchenipteridae species differ in the distribution, feeding habits and morphological traits: Auchenipterichthys longimanus (Günther, 1864, Auchenipterus nuchalis (Spix & Agassiz, 1829, Tatia intermedia (Steindachner, 1877 and Trachelyopterus galeatus (Linnaeus, 1766. This study was conducted in rivers and bays of the Anapú Basin, Pará State (Brazil, where these species are abundant. Specimens were collected using gillnets, and after caught the stomachs were removed for the contents analyzes. Eighteen morphometric measurements from ten adult specimens of each species were taken, combined into fifteen ecomorphological attributes. The species distribution showed that A. longimanus was restricted to rivers, while the others were exclusively caught in the bays. All four species had their diet composed of allochthonous insects, but A. longimanus also exhibited a great frugivorous habit. The most important ecomorphological attributes were relative to the consumption of larger food items (for A. longimanus and T. galeatus and to the longer swimming capacity (for A. longimanus and T. intermedia. These morphological differences and the trophic diversity presented in this study highlighted some important information about how ecomorphological similar species behave and share resources, which may play a significant role on the coexistence of these species in the Anapú Basin.

  15. Distribution and diversity of fungal species in and adjacent to the Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Balice, R.G.; Jarmie, N.; Rogers, F.J.

    1997-12-01

    Fungi have demonstrated their ability to diversify and specialize to take advantage of new environments (Murphy 1996). These species are essential to the normal functioning of ecosystems and the impacts of human activities may be harmful to fungi. There is a need to inventory fungi throughout the range of their environments. Previously archived information representing 43 sample locations was used to perform a preliminary evaluation of the distributions and diversity of fungal species at the Los Alamos National Laboratory and in adjacent environments. Presence-absence data for 71 species of fungi in five habitats, pinon-juniper, canyon-bottom ponderosa pine, ponderosa pine, canyon-bottom mixed conifer, and mixed conifer were analyzed. The results indicate that even though fungi occur in each of the habitats, fungal species are not distributed evenly among these habitats. The richness of fungal species is greater in the canyon-bottom mixed conifer and mixed conifer habitats than in the pinon-juniper, canyon-bottom ponderosa pine or ponderosa pine habitats. All but three of the fungal species were recorded in either the canyon-bottom mixed conifer or the mixed conifer habitats, and all but seven of the fungal species were found in the mixed conifer habitat.

  16. Distribution and diversity of fungal species in and adjacent to the Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Balice, R.G.; Jarmie, N.; Rogers, F.J.

    1997-12-01

    Fungi have demonstrated their ability to diversify and specialize to take advantage of new environments (Murphy 1996). These species are essential to the normal functioning of ecosystems and the impacts of human activities may be harmful to fungi. There is a need to inventory fungi throughout the range of their environments. Previously archived information representing 43 sample locations was used to perform a preliminary evaluation of the distributions and diversity of fungal species at the Los Alamos National Laboratory and in adjacent environments. Presence-absence data for 71 species of fungi in five habitats, pinon-juniper, canyon-bottom ponderosa pine, ponderosa pine, canyon-bottom mixed conifer, and mixed conifer were analyzed. The results indicate that even though fungi occur in each of the habitats, fungal species are not distributed evenly among these habitats. The richness of fungal species is greater in the canyon-bottom mixed conifer and mixed conifer habitats than in the pinon-juniper, canyon-bottom ponderosa pine or ponderosa pine habitats. All but three of the fungal species were recorded in either the canyon-bottom mixed conifer or the mixed conifer habitats, and all but seven of the fungal species were found in the mixed conifer habitat

  17. Geographic distribution of phlebotomine sandfly species (Diptera: Psychodidae) in Central-West Brazil

    Science.gov (United States)

    de Almeida, Paulo Silva; de Andrade, Andrey José; Sciamarelli, Alan; Raizer, Josué; Menegatti, Jaqueline Aparecida; Hermes, Sandra Cristina Negreli Moreira; de Carvalho, Maria do Socorro Laurentino; Gurgel-Gonçalves, Rodrigo

    2015-01-01

    This study updates the geographic distributions of phlebotomine species in Central-West Brazil and analyses the climatic factors associated with their occurrence. The data were obtained from the entomology services of the state departments of health in Central-West Brazil, scientific collections and a literature review of articles from 1962-2014. Ecological niche models were produced for sandfly species with more than 20 occurrences using the Maxent algorithm and eight climate variables. In all, 2,803 phlebotomine records for 127 species were analysed. Nyssomyia whitmani, Evandromyia lenti and Lutzomyia longipalpis were the species with the greatest number of records and were present in all the biomes in Central-West Brazil. The models, which were produced for 34 species, indicated that the Cerrado areas in the central and western regions of Central-West Brazil were climatically more suitable to sandflies. The variables with the greatest influence on the models were the temperature in the coldest months and the temperature seasonality. The results show that phlebotomine species in Central-West Brazil have different geographical distribution patterns and that climate conditions in essentially the entire region favour the occurrence of at least one Leishmania vector species, highlighting the need to maintain or intensify vector control and surveillance strategies. PMID:26018450

  18. Comparison of a species distribution model and a process model from a hierarchical perspective to quantify effects of projected climate change on tree species

    Science.gov (United States)

    Jeffrey E. Schneiderman; Hong S. He; Frank R. Thompson; William D. Dijak; Jacob S. Fraser

    2015-01-01

    Tree species distribution and abundance are affected by forces operating across a hierarchy of ecological scales. Process and species distribution models have been developed emphasizing forces at different scales. Understanding model agreement across hierarchical scales provides perspective on prediction uncertainty and ultimately enables policy makers and managers to...

  19. Antimicrobial Resistance

    Science.gov (United States)

    ... least 10 countries (Australia, Austria, Canada, France, Japan, Norway, Slovenia, South Africa, Sweden and the United Kingdom ... plan Global report on surveillance Country situation analysis Policy to combat antimicrobial resistance More on antimicrobial resistance ...

  20. Antimicrobial Resistance

    Science.gov (United States)

    ... can prevent and manage antimicrobial resistance. It is collaborating with partners to strengthen the evidence base and ... on the global action plan. WHO has been leading multiple initiatives to address antimicrobial resistance: World Antibiotic ...

  1. Implications of movement for species distribution models - Rethinking environmental data tools.

    Science.gov (United States)

    Bruneel, Stijn; Gobeyn, Sacha; Verhelst, Pieterjan; Reubens, Jan; Moens, Tom; Goethals, Peter

    2018-07-01

    Movement is considered an essential process in shaping the distributions of species. Nevertheless, most species distribution models (SDMs) still focus solely on environment-species relationships to predict the occurrence of species. Furthermore, the currently used indirect estimates of movement allow to assess habitat accessibility, but do not provide an accurate description of movement. Better proxies of movement are needed to assess the dispersal potential of individual species and to gain a more practical insight in the interconnectivity of communities. Telemetry techniques are rapidly evolving and highly capable to provide explicit descriptions of movement, but their usefulness for SDMs will mainly depend on the ability of these models to deal with hitherto unconsidered ecological processes. More specifically, the integration of movement is likely to affect the environmental data requirements as the connection between environmental and biological data is crucial to provide reliable results. Mobility implies the occupancy of a continuum of space, hence an adequate representation of both geographical and environmental space is paramount to study mobile species distributions. In this context, environmental models, remote sensing techniques and animal-borne environmental sensors are discussed as potential techniques to obtain suitable environmental data. In order to provide an in-depth review of the aforementioned methods, we have chosen to use the modelling of fish distributions as a case study. The high mobility of fish and the often highly variable nature of the aquatic environment generally complicate model development, making it an adequate subject for research. Furthermore, insight into the distribution of fish is of great interest for fish stock assessments and water management worldwide, underlining its practical relevance. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. An Objective Approach to Select Climate Scenarios when Projecting Species Distribution under Climate Change.

    Directory of Open Access Journals (Sweden)

    Nicolas Casajus

    Full Text Available An impressive number of new climate change scenarios have recently become available to assess the ecological impacts of climate change. Among these impacts, shifts in species range analyzed with species distribution models are the most widely studied. Whereas it is widely recognized that the uncertainty in future climatic conditions must be taken into account in impact studies, many assessments of species range shifts still rely on just a few climate change scenarios, often selected arbitrarily. We describe a method to select objectively a subset of climate change scenarios among a large ensemble of available ones. Our k-means clustering approach reduces the number of climate change scenarios needed to project species distributions, while retaining the coverage of uncertainty in future climate conditions. We first show, for three biologically-relevant climatic variables, that a reduced number of six climate change scenarios generates average climatic conditions very close to those obtained from a set of 27 scenarios available before reduction. A case study on potential gains and losses of habitat by three northeastern American tree species shows that potential future species distributions projected from the selected six climate change scenarios are very similar to those obtained from the full set of 27, although with some spatial discrepancies at the edges of species distributions. In contrast, projections based on just a few climate models vary strongly according to the initial choice of climate models. We give clear guidance on how to reduce the number of climate change scenarios while retaining the central tendencies and coverage of uncertainty in future climatic conditions. This should be particularly useful during future climate change impact studies as more than twice as many climate models were reported in the fifth assessment report of IPCC compared to the previous one.

  3. An Objective Approach to Select Climate Scenarios when Projecting Species Distribution under Climate Change.

    Science.gov (United States)

    Casajus, Nicolas; Périé, Catherine; Logan, Travis; Lambert, Marie-Claude; de Blois, Sylvie; Berteaux, Dominique

    2016-01-01

    An impressive number of new climate change scenarios have recently become available to assess the ecological impacts of climate change. Among these impacts, shifts in species range analyzed with species distribution models are the most widely studied. Whereas it is widely recognized that the uncertainty in future climatic conditions must be taken into account in impact studies, many assessments of species range shifts still rely on just a few climate change scenarios, often selected arbitrarily. We describe a method to select objectively a subset of climate change scenarios among a large ensemble of available ones. Our k-means clustering approach reduces the number of climate change scenarios needed to project species distributions, while retaining the coverage of uncertainty in future climate conditions. We first show, for three biologically-relevant climatic variables, that a reduced number of six climate change scenarios generates average climatic conditions very close to those obtained from a set of 27 scenarios available before reduction. A case study on potential gains and losses of habitat by three northeastern American tree species shows that potential future species distributions projected from the selected six climate change scenarios are very similar to those obtained from the full set of 27, although with some spatial discrepancies at the edges of species distributions. In contrast, projections based on just a few climate models vary strongly according to the initial choice of climate models. We give clear guidance on how to reduce the number of climate change scenarios while retaining the central tendencies and coverage of uncertainty in future climatic conditions. This should be particularly useful during future climate change impact studies as more than twice as many climate models were reported in the fifth assessment report of IPCC compared to the previous one.

  4. Using geomorphological variables to predict the spatial distribution of plant species in agricultural drainage networks.

    Science.gov (United States)

    Rudi, Gabrielle; Bailly, Jean-Stéphane; Vinatier, Fabrice

    2018-01-01

    To optimize ecosystem services provided by agricultural drainage networks (ditches) in headwater catchments, we need to manage the spatial distribution of plant species living in these networks. Geomorphological variables have been shown to be important predictors of plant distribution in other ecosystems because they control the water regime, the sediment deposition rates and the sun exposure in the ditches. Whether such variables may be used to predict plant distribution in agricultural drainage networks is unknown. We collected presence and absence data for 10 herbaceous plant species in a subset of a network of drainage ditches (35 km long) within a Mediterranean agricultural catchment. We simulated their spatial distribution with GLM and Maxent model using geomorphological variables and distance to natural lands and roads. Models were validated using k-fold cross-validation. We then compared the mean Area Under the Curve (AUC) values obtained for each model and other metrics issued from the confusion matrices between observed and predicted variables. Based on the results of all metrics, the models were efficient at predicting the distribution of seven species out of ten, confirming the relevance of geomorphological variables and distance to natural lands and roads to explain the occurrence of plant species in this Mediterranean catchment. In particular, the importance of the landscape geomorphological variables, ie the importance of the geomorphological features encompassing a broad environment around the ditch, has been highlighted. This suggests that agro-ecological measures for managing ecosystem services provided by ditch plants should focus on the control of the hydrological and sedimentological connectivity at the catchment scale. For example, the density of the ditch network could be modified or the spatial distribution of vegetative filter strips used for sediment trapping could be optimized. In addition, the vegetative filter strips could constitute

  5. Antimicrobials Treatment

    Science.gov (United States)

    Drosinos, Eleftherios H.; Skandamis, Panagiotis N.; Mataragas, Marios

    The use of antimicrobials is a common practice for preservation of foods. Incorporation, in a food recipe, of chemical antimicrobials towards inhibition of spoilage and pathogenic micro-organisms results in the compositional modification of food. This treatment is nowadays undesirable for the consumer, who likes natural products. Scientific community reflecting consumers demand for natural antimicrobials has made efforts to investigate the possibility to use natural antimicrobials such us bacteriocins and essential oils of plant origin to inhibit microbial growth.

  6. Species distribution modeling in regions of high need and limited data: waterfowl of China

    Science.gov (United States)

    Prosser, Diann J.; Ding, Changqing; Erwin, R. Michael; Mundkur, Taej; Sullivan, Jeffery D.; Ellis, Erle C.

    2018-01-01

    BackgroundA number of conservation and societal issues require understanding how species are distributed on the landscape, yet ecologists are often faced with a lack of data to develop models at the resolution and extent desired, resulting in inefficient use of conservation resources. Such a situation presented itself in our attempt to develop waterfowl distribution models as part of a multi-disciplinary team targeting the control of the highly pathogenic H5N1 avian influenza virus in China.MethodsFaced with limited data, we built species distribution models using a habitat suitability approach for China’s breeding and non-breeding (hereafter, wintering) waterfowl. An extensive review of the literature was used to determine model parameters for habitat modeling. Habitat relationships were implemented in GIS using land cover covariates. Wintering models were validated using waterfowl census data, while breeding models, though developed for many species, were only validated for the one species with sufficient telemetry data available.ResultsWe developed suitability models for 42 waterfowl species (30 breeding and 39 wintering) at 1 km resolution for the extent of China, along with cumulative and genus level species richness maps. Breeding season models showed highest waterfowl suitability in wetlands of the high-elevation west-central plateau and northeastern China. Wintering waterfowl suitability was highest in the lowland regions of southeastern China. Validation measures indicated strong performance in predicting species presence. Comparing our model outputs to China’s protected areas indicated that breeding habitat was generally better covered than wintering habitat, and identified locations for which additional research and protection should be prioritized.ConclusionsThese suitability models are the first available for many of China’s waterfowl species, and have direct utility to conservation and habitat planning and prioritizing management of critically

  7. Using Environmental DNA to Improve Species Distribution Models for Freshwater Invaders

    Directory of Open Access Journals (Sweden)

    Teja P. Muha

    2017-12-01

    Full Text Available Species Distribution Models (SDMs have been reported as a useful tool for the risk assessment and modeling of the pathways of dispersal of freshwater invasive alien species (IAS. Environmental DNA (eDNA is a novel tool that can help detect IAS at their early stage of introduction and additionally improve the data available for a more efficient management. SDMs rely on presence and absence of the species in the study area to infer the predictors affecting species distributions. Presence is verified once a species is detected, but confirmation of absence can be problematic because this depends both on the detectability of the species and the sampling strategy. eDNA is a technique that presents higher detectability and accuracy in comparison to conventional sampling techniques, and can effectively differentiate between presence or absence of specific species or entire communities by using a barcoding or metabarcoding approach. However, a number of potential bias can be introduced during (i sampling, (ii amplification, (iii sequencing, or (iv through the usage of bioinformatics pipelines. Therefore, it is important to report and conduct the field and laboratory procedures in a consistent way, by (i introducing eDNA independent observations, (ii amplifying and sequencing control samples, (iii achieving quality sequence reads by appropriate clean-up steps, (iv controlling primer amplification preferences, (v introducing PCR-free sequence capturing, (vi estimating primer detection capabilities through controlled experiments and/or (vii post-hoc introduction of “site occupancy-detection models.” With eDNA methodology becoming increasingly routine, its use is strongly recommended to retrieve species distributional data for SDMs.

  8. An experimental test of fitness variation across a hydrologic gradient predicts willow and poplar species distributions.

    Science.gov (United States)

    Wei, Xiaojing; Savage, Jessica A; Riggs, Charlotte E; Cavender-Bares, Jeannine

    2017-05-01

    Environmental filtering is an important community assembly process influencing species distributions. Contrasting species abundance patterns along environmental gradients are commonly used to provide evidence for environmental filtering. However, the same abundance patterns may result from alternative or concurrent assembly processes. Experimental tests are an important means to decipher whether species fitness varies with environment, in the absence of dispersal constraints and biotic interactions, and to draw conclusions about the importance of environmental filtering in community assembly. We performed an experimental test of environmental filtering in 14 closely related willow and poplar species (family Salicaceae) by transplanting cuttings of each species into 40 common gardens established along a natural hydrologic gradient in the field, where competition was minimized and herbivory was controlled. We analyzed species fitness responses to the hydrologic environment based on cumulative growth and survival over two years using aster fitness models. We also examined variation in nine drought and flooding tolerance traits expected to contribute to performance based on a priori understanding of plant function in relation to water availability and stress. We found substantial evidence that environmental filtering along the hydrologic gradient played a critical role in determining species distributions. Fitness variation of each species in the field experiment was used to model their water table depth optima. These optima predicted 68% of the variation in species realized hydrologic niches based on peak abundance in naturally assembled communities in the surrounding region. Multiple traits associated with water transport efficiency and water stress tolerance were correlated with species hydrologic niches, but they did not necessarily covary with each other. As a consequence, species occupying similar hydrologic niches had different combinations of trait values

  9. Diversity and Distribution of Freshwater Amphipod Species in Switzerland (Crustacea: Amphipoda)

    Science.gov (United States)

    Altermatt, Florian; Alther, Roman; Fišer, Cene; Jokela, Jukka; Konec, Marjeta; Küry, Daniel; Mächler, Elvira; Stucki, Pascal; Westram, Anja Marie

    2014-01-01

    Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems. PMID:25354099

  10. Modeling of the spatial distribution of ten endangered bird species in jurisdiction of Corantioquia

    International Nuclear Information System (INIS)

    Gomez M, Ana Maria; Alvarez, Esteban

    2006-01-01

    Recently, thanks to advances made in Geographic Information Systems (GIS), techniques have been developed for the construction of models that predict the spatial distribution of species and other attributes of biodiversity. These methods have allowed for the development of objective criteria that are fundamental for making decisions regarding the creation of protected areas systems throughout the world. In this research, the spatial distribution of ten endangered species of birds found within the jurisdiction of CORANTIOQUIA (JDC from here on) was modelled, using GIS techniques. The JDC was divided into 177 squares of 15 x 10 Km and the following variables were quantified within each one: presence or absence of endangered species of birds, rainfall, temperature, sun brightness, relative humidity, day duration, altitude, vegetal cover, slope and primary net productivity. With the help of logistic regression were made predictive models. Based on logistic regressions techniques predictive models were made. These models allow to explain a percentage between 24% and 80% of spatial distribution variability of these species. Those results can help in the identification of valuable zones for the biodiversity conservation. In places where there are neither the time or the economic resources to carry out exhaustive analyses of biodiversity, the models can predict the probable presence of this endangered species

  11. Probabilistic accounting of uncertainty in forecasts of species distributions under climate change

    Science.gov (United States)

    Seth J. Wenger; Nicholas A. Som; Daniel C. Dauwalter; Daniel J. Isaak; Helen M. Neville; Charles H. Luce; Jason B. Dunham; Michael K. Young; Kurt D. Fausch; Bruce E. Rieman

    2013-01-01

    Forecasts of species distributions under future climates are inherently uncertain, but there have been few attempts to describe this uncertainty comprehensively in a probabilistic manner. We developed a Monte Carlo approach that accounts for uncertainty within generalized linear regression models (parameter uncertainty and residual error), uncertainty among competing...

  12. Functional traits, drought performance, and the distribution of tree species in tropical forests of Ghana

    NARCIS (Netherlands)

    Amissah, L.

    2014-01-01

    Tropical forests occur along a rainfall gradient where annual amount, the length and intensity of dry season vary and water availability shapes therefore strongly the distribution of tree species. Annual rainfall in West Africa has declined at a rate of 4% per decade, and climate change

  13. Moisture and nutrients determine the distribution and richness of India's large herbivore species assemblage

    NARCIS (Netherlands)

    Ahrestani, F.S.; Heitkonig, I.M.A.; Langevelde, van F.; Vaidyanathan, S.; Madhusudan, M.D.; Prins, H.H.T.

    2011-01-01

    The goal of this study was to test whether body-mass based foraging principles, guided by plant available moisture (PAM) and plant available nutrients (PAN), could explain large mammalian herbivore species distribution and richness in India. We tested (1) whether the occurrence of larger-bodied

  14. Species richness and distribution of understorey bryophytes in different forest types in Colombian Amazonia

    NARCIS (Netherlands)

    Benavides, J.C.; Duque, A.J.; Duivenvoorden, J.F.; Cleef, A.M.

    2006-01-01

    The first bryophyte survey results from Colombian Amazonia are presented. Bryophyte species, differentiated into mosses and liverworts, and further into four life-form classes, were sampled in 0.1-ha plots. These plots were distributed over four landscape units in the middle Caquetá area:

  15. Soil moisture and biogeochemical factors influence the distribution of annual Bromus species

    Science.gov (United States)

    Jayne Belnap; John M. Stark; Benjamin M. Rau; Edith B. Allen; Susan Phillips

    2016-01-01

    Abiotic factors have a strong influence on where annual Bromus species are found. At the large regional scale, temperature and precipitation extremes determine the boundaries of Bromus occurrence. At the more local scale, soil characteristics and climate influence distribution, cover, and performance. In hot, dry, summer-rainfall-dominated deserts (Sonoran, Chihuahuan...

  16. Distribution and diversity of Arctic-Alpine species in the Balkans

    DEFF Research Database (Denmark)

    Stevanovic, Vladimir; Vukojicic, Snezana; Sinzar-Sekulic, Jasmina

    2009-01-01

    The distributions of 77 Arctic-Alpine species in the Balkans are mapped and the centers of their richness and diversity presented. Within the Dinaric Alps these are Mts Vranica, Durmitor, and Prokletije; in the Scardo-Pindhic mountains, Šarplanina-Rudoka-Korab form a continuous chain...

  17. Spatial regression methods capture prediction uncertainty in species distribution model projections through time

    Science.gov (United States)

    Alan K. Swanson; Solomon Z. Dobrowski; Andrew O. Finley; James H. Thorne; Michael K. Schwartz

    2013-01-01

    The uncertainty associated with species distribution model (SDM) projections is poorly characterized, despite its potential value to decision makers. Error estimates from most modelling techniques have been shown to be biased due to their failure to account for spatial autocorrelation (SAC) of residual error. Generalized linear mixed models (GLMM) have the ability to...

  18. Distributional and natural history notes on five species of amphibians and reptiles from Isla Ometepe, Nicaragua

    NARCIS (Netherlands)

    Stark, T.; Laurijssens, C.; Weterings, M.J.A.

    2014-01-01

    Relative to the size of the country, the herpetofauna of Nicaragua remains one of the most understudied in Central America (Sunyer et al., 2014). The discovery of new herpetofaunal species in the country and distributional records for certain taxa, however, are not uncommon (Sunyer and Köhler, 2007;

  19. New Data on the Vertical Distribution of Some Species of the Flora in Bulgaria

    Directory of Open Access Journals (Sweden)

    Alexander Tashev

    2013-12-01

    Full Text Available During field studies in different floristic regions of Bulgaria in the period 2006-2013, we found localities of Stellaria alsine, Trifolium heldreichianum, Koeleria nitidula, Sieglingia decumbens, Stipa tirsa, Verbascum formanekii, Pedicularis leucodon, Saxifraga stribrnyi, Inula aschersoniana and Scilla bifolia that expand our knowledge of the vertical distribution of these species in Bulgaria, and hence their ecological niche in the country.

  20. Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species.

    Science.gov (United States)

    Lima, Robson B DE; Bufalino, Lina; Alves, Francisco T; Silva, José A A DA; Ferreira, Rinaldo L C

    2017-01-01

    Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

  1. Patterns in species richness and distribution of vascular epiphytes in Chiapas, Mexico

    NARCIS (Netherlands)

    Wolf, J.H.D.; Flamenco-S., A.

    2003-01-01

    Aim We aim to assess regional patterns in the distribution and species richness of vascular epiphytes with an emphasis on forests that differ in altitude and the amount of rainfall. Location Tropical America, in particularly the 75000 km2 large state of Chiapas in southern Mexico at 14.5-18.0º N.

  2. Confirming the species-sensitivity distribution concept for endosulfan using laboratory, mesocosm, and field data

    NARCIS (Netherlands)

    Hose, G.C.; Brink, van den P.J.

    2004-01-01

    In Australia, water-quality trigger values for toxicants are derived using protective concentration values based on species-sensitivity distribution (SSD) curves. SSD curves are generally derived from laboratory data with an emphasis on using local or site-specific data. In this study, Australian

  3. Species Distribution Modelling: Contrasting presence-only models with plot abundance data

    NARCIS (Netherlands)

    Gomes, Vitor H.F.; Ijff, Stéphanie D.; Raes, Niels; Amaral, Iêda Leão; Salomão, Rafael P.; Coelho, Luiz De Souza; Matos, Francisca Dionízia De Almeida; Castilho, Carolina V.; Filho, Diogenes De Andrade Lima; López, Dairon Cárdenas; Guevara, Juan Ernesto; Magnusson, William E.; Phillips, Oliver L.; Wittmann, Florian; Carim, Marcelo De Jesus Veiga; Martins, Maria Pires; Irume, Mariana Victória; Sabatier, Daniel; Molino, Jean François; Bánki, Olaf S.; Guimarães, José Renan Da Silva; Pitman, Nigel C.A.; Piedade, Maria Teresa Fernandez; Mendoza, Abel Monteagudo; Luize, Bruno Garcia; Venticinque, Eduardo Martins; Novo, Evlyn Márcia Moraes De Leão; Vargas, Percy Núñez; Silva, Thiago Sanna Freire; Manzatto, Angelo Gilberto; Terborgh, John; Reis, Neidiane Farias Costa; Montero, Juan Carlos; Casula, Katia Regina; Marimon, Beatriz S.; Marimon, Ben Hur; Coronado, Euridice N.Honorio; Feldpausch, Ted R.; Duque, Alvaro; Zartman, Charles Eugene; Arboleda, Nicolás Castaño; Killeen, Timothy J.; Mostacedo, Bonifacio; Vasquez, Rodolfo; Schöngart, Jochen; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Laurance, William F.; Camargo, José Luís; Demarchi, Layon O.; Laurance, Susan G.W.; Farias, Emanuelle De Sousa; Nascimento, Henrique Eduardo Mendonça; Revilla, Juan David Cardenas; Quaresma, Adriano; Costa, Flavia R.C.; Vieira, Ima Célia Guimarães; Cintra, Bruno Barçante Ladvocat; Castellanos, Hernán; Brienen, Roel; Stevenson, Pablo R.; Feitosa, Yuri; Duivenvoorden, Joost F.; Aymard, Gerardo A.C.; Mogollón, Hugo F.; Targhetta, Natalia; Comiskey, James A.; Vicentini, Alberto; Lopes, Aline; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Emilio, Thaise; Alonso, Alfonso; Neill, David; Dallmeier, Francisco; Ferreira, Leandro Valle; Araujo-Murakami, Alejandro; Praia, Daniel; Do Amaral, Dário Dantas; Carvalho, Fernanda Antunes; De Souza, Fernanda Coelho; Feeley, Kenneth; Arroyo, Luzmila; Pansonato, Marcelo Petratti; Gribel, Rogerio; Villa, Boris; Licona, Juan Carlos; Fine, Paul V.A.; Cerón, Carlos; Baraloto, Chris; Jimenez, Eliana M.; Stropp, Juliana; Engel, Julien; Silveira, Marcos; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Maas, Paul; Thomas-Caesar, Raquel; Henkel, Terry W.; Daly, Doug; Paredes, Marcos Ríos; Baker, Tim R.; Fuentes, Alfredo; Peres, Carlos A.; Chave, Jerome; Pena, Jose Luis Marcelo; Dexter, Kyle G.; Silman, Miles R.; Jørgensen, Peter Møller; Pennington, Toby; Di Fiore, Anthony; Valverde, Fernando Cornejo; Phillips, Juan Fernando; Rivas-Torres, Gonzalo; Von Hildebrand, Patricio; Van Andel, Tinde R.; Ruschel, Ademir R.; Prieto, Adriana; Rudas, Agustín; Hoffman, Bruce; Vela, César I.A.; Barbosa, Edelcilio Marques; Zent, Egleé L.; Gonzales, George Pepe Gallardo; Doza, Hilda Paulette Dávila; Miranda, Ires Paula De Andrade; Guillaumet, Jean Louis; Pinto, Linder Felipe Mozombite; Bonates, Luiz Carlos De Matos; Silva, Natalino; Gómez, Ricardo Zárate; Zent, Stanford; Gonzales, Therany; Vos, Vincent A.; Malhi, Yadvinder; Oliveira, Alexandre A.; Cano, Angela; Albuquerque, Bianca Weiss; Vriesendorp, Corine; Correa, Diego Felipe; Torre, Emilio Vilanova; Van Der Heijden, Geertje; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Young, Kenneth R.; Rocha, Maira; Nascimento, Marcelo Trindade; Medina, Maria Natalia Umaña; Tirado, Milton; Wang, Ophelia; Sierra, Rodrigo; Torres-Lezama, Armando; Mendoza, Casimiro; Ferreira, Cid; Baider, Cláudia; Villarroel, Daniel; Balslev, Henrik; Mesones, Italo; Giraldo, Ligia Estela Urrego; Casas, Luisa Fernanda; Reategui, Manuel Augusto Ahuite; Linares-Palomino, Reynaldo; Zagt, Roderick; Cárdenas, Sasha; Farfan-Rios, William; Sampaio, Adeilza Felipe; Pauletto, Daniela; Sandoval, Elvis H.Valderrama; Arevalo, Freddy Ramirez; Huamantupa-Chuquimaco, Isau; Garcia-Cabrera, Karina; Hernandez, Lionel; Gamarra, Luis Valenzuela; Alexiades, Miguel N.; Pansini, Susamar; Cuenca, Walter Palacios; Milliken, William; Ricardo, Joana; Lopez-Gonzalez, Gabriela; Pos, Edwin; Ter Steege, Hans

    2018-01-01

    Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs.

  4. Selection bias in species distribution models: An econometric approach on forest trees based on structural modeling

    Science.gov (United States)

    Martin-StPaul, N. K.; Ay, J. S.; Guillemot, J.; Doyen, L.; Leadley, P.

    2014-12-01

    Species distribution models (SDMs) are widely used to study and predict the outcome of global changes on species. In human dominated ecosystems the presence of a given species is the result of both its ecological suitability and human footprint on nature such as land use choices. Land use choices may thus be responsible for a selection bias in the presence/absence data used in SDM calibration. We present a structural modelling approach (i.e. based on structural equation modelling) that accounts for this selection bias. The new structural species distribution model (SSDM) estimates simultaneously land use choices and species responses to bioclimatic variables. A land use equation based on an econometric model of landowner choices was joined to an equation of species response to bioclimatic variables. SSDM allows the residuals of both equations to be dependent, taking into account the possibility of shared omitted variables and measurement errors. We provide a general description of the statistical theory and a set of applications on forest trees over France using databases of climate and forest inventory at different spatial resolution (from 2km to 8km). We also compared the outputs of the SSDM with outputs of a classical SDM (i.e. Biomod ensemble modelling) in terms of bioclimatic response curves and potential distributions under current climate and climate change scenarios. The shapes of the bioclimatic response curves and the modelled species distribution maps differed markedly between SSDM and classical SDMs, with contrasted patterns according to species and spatial resolutions. The magnitude and directions of these differences were dependent on the correlations between the errors from both equations and were highest for higher spatial resolutions. A first conclusion is that the use of classical SDMs can potentially lead to strong miss-estimation of the actual and future probability of presence modelled. Beyond this selection bias, the SSDM we propose represents

  5. A species-specific nucleosomal signature defines a periodic distribution of amino acids in proteins.

    Science.gov (United States)

    Quintales, Luis; Soriano, Ignacio; Vázquez, Enrique; Segurado, Mónica; Antequera, Francisco

    2015-04-01

    Nucleosomes are the basic structural units of chromatin. Most of the yeast genome is organized in a pattern of positioned nucleosomes that is stably maintained under a wide range of physiological conditions. In this work, we have searched for sequence determinants associated with positioned nucleosomes in four species of fission and budding yeasts. We show that mononucleosomal DNA follows a highly structured base composition pattern, which differs among species despite the high degree of histone conservation. These nucleosomal signatures are present in transcribed and non-transcribed regions across the genome. In the case of open reading frames, they correctly predict the relative distribution of codons on mononucleosomal DNA, and they also determine a periodicity in the average distribution of amino acids along the proteins. These results establish a direct and species-specific connection between the position of each codon around the histone octamer and protein composition.

  6. Evaluating the combined effects of climate and land-use change on tree species distributions

    DEFF Research Database (Denmark)

    Garcia-Valdes, Raul; Svenning, Jens-Christian; Zavala, Miguel A.

    2015-01-01

    Summary: A large proportion of the world's biodiversity is reportedly threatened by habitat loss and climate change. However, there are few studies that investigate the interaction between these two threats using empirical data. Here, we investigate interactions between climate change and land-use...... change in the future distribution of 23 dominant tree species in mainland Spain. We simulated changes up to year 2100 using a climate-dependent Stochastic Patch Occupancy Model, parameterized with colonization and extinction events recorded in 46 596 survey plots. We estimated that the distribution of 17......% of the habitat, was estimated to reduce species occupancies (relative to baseline projections) by an average of 23% if habitat loss was spatially clumped, and by 35% if it was scattered. If habitat loss occurred in areas already impacted by human activities, species occupancies would be reduced by 26%. Land-use...

  7. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis

    Science.gov (United States)

    Kato, Hirotomo; Gomez, Eduardo A.; Martini-Robles, Luiggi; Muzzio, Jenny; Velez, Lenin; Calvopiña, Manuel; Romero-Alvarez, Daniel; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

    2016-01-01

    A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL) in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia) guyanensis, L. (V.) braziliensis, L. (V.) naiffi, L. (V.) lainsoni, and L. (Leishmania) mexicana. Two dominant species, L. (V.) guyanensis and L. (V.) braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V.) naiffi and L. (V.) lainsoni were identified in Amazonian areas, and L. (L.) mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V.) braziliensis infection are increasing in Pacific coast areas. PMID:27410039

  8. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis.

    Science.gov (United States)

    Kato, Hirotomo; Gomez, Eduardo A; Martini-Robles, Luiggi; Muzzio, Jenny; Velez, Lenin; Calvopiña, Manuel; Romero-Alvarez, Daniel; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

    2016-07-01

    A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL) in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia) guyanensis, L. (V.) braziliensis, L. (V.) naiffi, L. (V.) lainsoni, and L. (Leishmania) mexicana. Two dominant species, L. (V.) guyanensis and L. (V.) braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V.) naiffi and L. (V.) lainsoni were identified in Amazonian areas, and L. (L.) mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V.) braziliensis infection are increasing in Pacific coast areas.

  9. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis.

    Directory of Open Access Journals (Sweden)

    Hirotomo Kato

    2016-07-01

    Full Text Available A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia guyanensis, L. (V. braziliensis, L. (V. naiffi, L. (V. lainsoni, and L. (Leishmania mexicana. Two dominant species, L. (V. guyanensis and L. (V. braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V. naiffi and L. (V. lainsoni were identified in Amazonian areas, and L. (L. mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V. braziliensis infection are increasing in Pacific coast areas.

  10. Distribution, habitat affinities and phenology of the Micrargus herbigradus-species group (Araneae: Linyphiidae) in Poland.

    Science.gov (United States)

    Wiśniewski, Konrad; Rozwałka, Robert; Wesołowska, Wanda

    2018-01-01

    We review the known information on the distribution and habitat affinities of the Micrargus herbigradus -species group in Poland. The analysis is based on a thorough literature survey, our own materials, and verification of some older collections. We give new diagnostic drawings and review the characters that are useful in identification of species within the group. Three species are present in Poland: M. herbigradus (Blackwall, 1854), M. apertus (O.-P. Cambridge, 1870) and M. georgescuae Millidge, 1976. The latter is recorded for the first time in the country, and we add numerous new localities for the two former species. Micrargus herbigradus is common and widespread in Poland, living in various habitats, with only a slight preference to forests. In contrast, M. apertus is widely distributed but rarely found, while its affinity to forests is the highest within the group. The records of this species are most numerous in lowland forests (up to c. 300 m a.s.l), but it can also be found at higher altitudes. M. georgescuae is found only in montane habitats, both in the Sudetes and the Carpathian Mountains, from above 650 m a.s.l. The adults of all three species occur the whole year round, but seem to be most abundant in May and June.

  11. Distribution of the Chuckwalla, Western Burrowing Owl, and Six Bat Species on the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Cathy A. Willis

    1997-05-01

    Field Surveys were conducted in 1996 to determine the current distribution of several animal species of concern on the Nevada Test Site (NTS). They included the chuckwall (Sauromalus obesus), western burrowing owl (Speotyto cunicularia), and six species of bats. Nineteen chuckwallas and 118 scat locations were found during the chuckwalla field study. Eighteen western burrowing owls were found at 12 sighting locations during the 1996 field study. Of the eleven bat species of concern which might occur on the NTS, five, and possibly six, were captured during this survey. The U.S. Department of Energy, Nevada Operations Office, takes certain management actions to protect and conserve the chuckwalla, western burrowing owl, and bats on the NTS. These actions are described and include: (1) conducting surveys at sites of proposed land-disturbing activities (2) altering projects whenever possible to avoid or minimize impacts to these species (3) maintaining a geospatial database of known habitat for species of concern (4) sharing sighting and trap location data gathered on the NTS with other local land and resource managers, and (5) conducting periodic field surveys to monitor these species distribution and relative abundance on the NTS.

  12. Inferential monitoring of global change impact on biodiversity through remote sensing and species distribution modeling

    Science.gov (United States)

    Sangermano, Florencia

    2009-12-01

    The world is suffering from rapid changes in both climate and land cover which are the main factors affecting global biodiversity. These changes may affect ecosystems by altering species distributions, population sizes, and community compositions, which emphasizes the need for a rapid assessment of biodiversity status for conservation and management purposes. Current approaches on monitoring biodiversity rely mainly on long term observations of predetermined sites, which require large amounts of time, money and personnel to be executed. In order to overcome problems associated with current field monitoring methods, the main objective of this dissertation is the development of framework for inferential monitoring of the impact of global change on biodiversity based on remotely sensed data coupled with species distribution modeling techniques. Several research pieces were performed independently in order to fulfill this goal. First, species distribution modeling was used to identify the ranges of 6362 birds, mammals and amphibians in South America. Chapter 1 compares the power of different presence-only species distribution methods for modeling distributions of species with different response curves to environmental gradients and sample sizes. It was found that there is large variability in the power of the methods for modeling habitat suitability and species ranges, showing the importance of performing, when possible, a preliminary gradient analysis of the species distribution before selecting the method to be used. Chapter 2 presents a new methodology for the redefinition of species range polygons. Using a method capable of establishing the uncertainty in the definition of existing range polygons, the automated procedure identifies the relative importance of bioclimatic variables for the species, predicts their ranges and generates a quality assessment report to explore prediction errors. Analysis using independent validation data shows the power of this

  13. BAYESIAN MODELS FOR SPECIES DISTRIBUTION MODELLING WITH ONLY-PRESENCE RECORDS

    Directory of Open Access Journals (Sweden)

    Bartolo de Jesús Villar-Hernández

    2015-08-01

    Full Text Available One of the central issues in ecology is the study of geographical distribution of species of flora and fauna through Species Distribution Models (SDM. Recently, scientific interest has focused on presence-only records. Two recent approaches have been proposed for this problem: a model based on maximum likelihood method (Maxlike and an inhomogeneous poisson process model (IPP. In this paper we discussed two bayesian approaches called MaxBayes and IPPBayes based on Maxlike and IPP model, respectively. To illustrate these proposals, we implemented two study examples: (1 both models were implemented on a simulated dataset, and (2 we modeled the potencial distribution of genus Dalea in the Tehuacan-Cuicatlán biosphere reserve with both models, the results was compared with that of Maxent. The results show that both models, MaxBayes and IPPBayes, are viable alternatives when species distribution are modeled with only-presence records. For simulated dataset, MaxBayes achieved prevalence estimation, even when the number of records was small. In the real dataset example, both models predict similar potential distributions like Maxent does. Â

  14. Incorporating spatial autocorrelation into species distribution models alters forecasts of climate-mediated range shifts.

    Science.gov (United States)

    Crase, Beth; Liedloff, Adam; Vesk, Peter A; Fukuda, Yusuke; Wintle, Brendan A

    2014-08-01

    Species distribution models (SDMs) are widely used to forecast changes in the spatial distributions of species and communities in response to climate change. However, spatial autocorrelation (SA) is rarely accounted for in these models, despite its ubiquity in broad-scale ecological data. While spatial autocorrelation in model residuals is known to result in biased parameter estimates and the inflation of type I errors, the influence of unmodeled SA on species' range forecasts is poorly understood. Here we quantify how accounting for SA in SDMs influences the magnitude of range shift forecasts produced by SDMs for multiple climate change scenarios. SDMs were fitted to simulated data with a known autocorrelation structure, and to field observations of three mangrove communities from northern Australia displaying strong spatial autocorrelation. Three modeling approaches were implemented: environment-only models (most frequently applied in species' range forecasts), and two approaches that incorporate SA; autologistic models and residuals autocovariate (RAC) models. Differences in forecasts among modeling approaches and climate scenarios were quantified. While all model predictions at the current time closely matched that of the actual current distribution of the mangrove communities, under the climate change scenarios environment-only models forecast substantially greater range shifts than models incorporating SA. Furthermore, the magnitude of these differences intensified with increasing increments of climate change across the scenarios. When models do not account for SA, forecasts of species' range shifts indicate more extreme impacts of climate change, compared to models that explicitly account for SA. Therefore, where biological or population processes induce substantial autocorrelation in the distribution of organisms, and this is not modeled, model predictions will be inaccurate. These results have global importance for conservation efforts as inaccurate

  15. Standard test method for distribution coefficients of inorganic species by the batch method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of distribution coefficients of chemical species to quantify uptake onto solid materials by a batch sorption technique. It is a laboratory method primarily intended to assess sorption of dissolved ionic species subject to migration through pores and interstices of site specific geomedia. It may also be applied to other materials such as manufactured adsorption media and construction materials. Application of the results to long-term field behavior is not addressed in this method. Distribution coefficients for radionuclides in selected geomedia are commonly determined for the purpose of assessing potential migratory behavior of contaminants in the subsurface of contaminated sites and waste disposal facilities. This test method is also applicable to studies for parametric studies of the variables and mechanisms which contribute to the measured distribution coefficient. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement a...

  16. Facilitating political decisions using species distribution models to assess restoration measures in heavily modified estuaries.

    Science.gov (United States)

    Heuner, Maike; Weber, Arnd; Schröder, Uwe; Kleinschmit, Birgit; Schröder, Boris

    2016-09-15

    The European Water Framework Directive requires a good ecological potential for heavily modified water bodies. This standard has not been reached for most large estuaries by 2015. Management plans for estuaries fall short in linking implementations between restoration measures and underlying spatial analyses. The distribution of emergent macrophytes - as an indicator of habitat quality - is here used to assess the ecological potential. Emergent macrophytes are capable of settling on gentle tidal flats where hydrodynamic stress is comparatively low. Analyzing their habitats based on spatial data, we set up species distribution models with 'elevation relative to mean high water', 'mean bank slope', and 'length of bottom friction' from shallow water up to the vegetation belt as key predictors representing hydrodynamic stress. Effects of restoration scenarios on habitats were assessed applying these models. Our findings endorse species distribution models as crucial spatial planning tools for implementing restoration measures in modified estuaries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species

    Directory of Open Access Journals (Sweden)

    Monahan William B

    2012-03-01

    relative importance of features that define barriers, (ii can be replicated using any kind of continuously distributed environmental variable, and (iii generates spatially explicit hypotheses of geographic species formation. The methods developed here - combined with study of the geographical ecology and genetics of taxa in their environments - should enable recognition of ring species phenomena throughout the world.

  18. Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species.

    Science.gov (United States)

    Monahan, William B; Pereira, Ricardo J; Wake, David B

    2012-03-12

    In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (barriers - formed by groups of barriers (each 184,000 to 1.7 million km2) in close geographic proximity (totaling 1.9 to 2.3 million km2) - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus)). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no a priori information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of

  19. Morphometry and Distribution of Senecio Nemorensis agg. Species (Asteraceae in Poland

    Directory of Open Access Journals (Sweden)

    Rola Kaja

    2014-07-01

    Full Text Available A morphometric analysis based on 316 herbarium specimens of Senecio nemorensis agg. indicated the occurrence of the following four species in Poland: S. germanicus Wallr., S. hercynicus Herborg, S. ovatus (G. Gaertn. et al. Willd. and S. ucranicus Hodálová. Principal component analysis (PCA, analysis of variance (ANOVA/Kruskal-Wallis test and canonical discriminant analysis (CDA were applied. Quantitative characters such as supplementary bract length, leaf base width, ligule length and the supplementary/involucral bract length ratio clearly discriminated taxa within S. nemorensis agg. Included is a distribution map of the investigated species based on the examined material, with particular emphasis on the course of the northeastern boundary of S. hercynicus and the northwestern boundary of S. ucranicus. Also given is a determination key for species within S. nemorensis agg. in Poland, together with morphological descriptions of particular species

  20. Distribution of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (Russia).

    Science.gov (United States)

    Chadin, Ivan; Dalke, Igor; Zakhozhiy, Ilya; Malyshev, Ruslan; Madi, Elena; Olga Kuzivanova; Kirillov, Dmitrii; Elsakov, Vladimir

    2017-01-01

    Occurrences of the invasive plant species Heracleum sosnowskyi Manden. in the Komi Republic (northeastern part of European Russia) were recorded and published in the Global Biodiversity Information Facility (GBIF http://www.gbif.org) using the RIVR information system (http://ib.komisc.ru/add/rivr/en). RIVR stands for "Rasprostranenie Invasionnyh Vidov Rastenij" [Occurrence of Invasion Plant Species]. This citizen science project aims at collecting occurrence data about invasive plant species with the help of citizen scientists. Information can be added by any user after a simple registration (concept) process. However, the data published in GBIF are provided only by professional scientists. The total study area is approximately 19,000 km 2 . The GBIF resource contains 10894 Heracleum sosnowskyi occurrence points, each with their geographical coordinates and photographs of the plants in the locus of growth. The preliminary results of species distribution modelling on the territory of European North-East Russia presented.

  1. Two Ganoderma species: profiling of phenolic compounds by HPLC-DAD, antioxidant, antimicrobial and inhibitory activities on key enzymes linked to diabetes mellitus, Alzheimer's disease and skin disorders.

    Science.gov (United States)

    Zengin, Gokhan; Sarikurkcu, Cengiz; Gunes, Erdogan; Uysal, Ahmet; Ceylan, Ramazan; Uysal, Sengul; Gungor, Halil; Aktumsek, Abdurrahman

    2015-08-01

    This work reports the antioxidant, antimicrobial, and inhibitory effects of methanol and water extracts from Ganoderma applanatum (GAM: methanol extract and GAW: water extract) and G. resinaceum (GRM: methanol extract and GRW: water extract) against cholinesterase, tyrosinase, α-amylase and α-glucosidase. The total phenolics, flavonoids contents, and HPLC profile of phenolic components present in the extracts, were also determined. Antioxidant activities were investigated by using different assays, including DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum and metal chelating assays. Antimicrobial activity of the tested Ganoderma extracts was also studied by the broth microdilution method. Generally, the highest antioxidant (59.24 mg TEs per g extract for DPPH, 41.32 mg TEs per g extract for ABTS, 41.35 mg TEs per g extract for CUPRAC, 49.68 mg TEs per g extract for FRAP, 130.57 mg AAEs per g extract for phosphomolybdenum and 26.92 mg EDTAEs per g extract) and enzyme inhibitory effects (1.47 mg GALAEs per g extract for AChE, 1.51 mg GALAEs per g extract for BChE, 13.40 mg KAEs per g extract for tyrosinase, 1.13 mmol ACEs per g extract for α-amylase and 2.20 mmol ACEs per g extract for α-glucosidase) were observed in GRM, which had the highest concentrations of phenolics (37.32 mg GAEs g(-1) extract). Again, Ganoderma extracts possess weak antibacterial and antifungal activities. Apigenin and protocatechuic acid were determined as the main components in GRM (1761 μg per g extract) and GAM (165 μg per g extract), respectively. The results suggest that the Ganoderma species may be considered as a candidate for preparing new food supplements and can represent a good model for the development of new drug formulations.

  2. Distribution

    Science.gov (United States)

    John R. Jones

    1985-01-01

    Quaking aspen is the most widely distributed native North American tree species (Little 1971, Sargent 1890). It grows in a great diversity of regions, environments, and communities (Harshberger 1911). Only one deciduous tree species in the world, the closely related Eurasian aspen (Populus tremula), has a wider range (Weigle and Frothingham 1911)....

  3. Using Bioassays and Species Sensitivity Distributions to Assess Herbicide Toxicity towards Benthic Diatoms

    Science.gov (United States)

    Larras, Floriane; Bouchez, Agnès; Rimet, Frédéric; Montuelle, Bernard

    2012-01-01

    Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD) could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC5) and the Effective Concentration 50 (EC50) for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC5) and 50 (HC50). Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII) herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and “motile” guild species were more tolerant of PSII inhibitors, while N-autotroph and “low profile” guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron. PMID:22952981

  4. Species composition and bathymetric distribution of gorgonians (Anthozoa: Octocorallia on the Southern Mexican Pacific coast

    Directory of Open Access Journals (Sweden)

    Rosalinda Abeytia

    2013-09-01

    Full Text Available Gorgonians are important components of coastal ecosystems, as they provide niches, natural compounds with medical applications and are used as bioindicators. Species composition and assemblage structure of gorgonians (Anthozoa: Octocorallia were studied along a bathymetric profile in the Southern Mexican Pacific coast. Species composition was based on specimens collected within a depth range of 0-70m in 15 sites. The relative abundance of species was determined in six sites at four depths (5, 10, 20 and 25m using three 10m2 transects at each depth level. Twenty-seven species of gorgonians belonging to six genera and three families were registered. The species composition varied with depth: 11 species were distributed between 0-25m depth, while 17 species were found between 40-70m depth interval. The shallow zone is characterized by a relatively large abundance of gorgonians, dominated by colonies of Leptogorgia cuspidata and L. ena. In contrast, the deepest zone was characterized by relatively low abundance of gorgonians, dominated by L. alba, the only species observed in both depth intervals. The similarity analysis showed differences in the composition and abundance of species by depth and site, suggesting that the main factor in determining the assemblage structure is depth. Results of this study suggest that the highest richness of gorgonian species in the study area may be located at depths of 40-70m, whereas the highest abundances are found between 5 and 10m depth. This study represents a contribution to the poorly known eastern Pacific gorgonian biota.

  5. Using bioassays and species sensitivity distributions to assess herbicide toxicity towards benthic diatoms.

    Directory of Open Access Journals (Sweden)

    Floriane Larras

    Full Text Available Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC(5 and the Effective Concentration 50 (EC(50 for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC(5 and 50 (HC(50. Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and "motile" guild species were more tolerant of PSII inhibitors, while N-autotroph and "low profile" guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron.

  6. Floristic composition, environmental variation and species distribution patterns in burned grassland in southern Brazil.

    Science.gov (United States)

    Overbeck, G E; Müller, S C; Pillar, V D; Pfadenhauer, J

    2006-11-01

    In regularly burned grassland on Morro Santana, Porto Alegre, RS, Brazil, we investigated differences in the floristic composition and their relation to soil properties, aspect and distance from the forest border. In 48 plots of 0.75 m2, we identified a total of 201 species from a local species pool of approximately 450 to 500 species. Most species occurred in low frequencies, showing clumpy distribution patterns in the studied area. Multivariate analysis showed that plots close to the forest edge clearly differed from plots in the open grassland concerning composition and structure. Plots exposed to the north differed from plots on the top of the hill both in the composition of species as well as in soil variables, mainly due to shallower soil in the former. No strong relation between soil properties and variation in vegetation composition could be detected at a finer scale. The studied grassland, as all grassland vegetation in southern Brazil, is very rich in species compared to other grassland formations worldwide. However, this high biodiversity and conservational value of Campos vegetation in general has so far not been recognized properly. Disturbance is essential to maintain this open vegetation type and its species richness. Fire should be considered as a management option in the absence of grazing.

  7. Antitropical distributions and species delimitation in a group of ophiocomid brittle stars (Echinodermata: Ophiuroidea: Ophiocomidae).

    Science.gov (United States)

    Naughton, K M; O'Hara, T D; Appleton, B; Cisternas, P A

    2014-09-01

    In this paper we examine the phylogeny and biogeography of the temperate genera of the Ophiocomidae (Echinodermata: Ophiuroidea) which have an interesting asymmetrical anti-tropical distribution, with two genera (Ophiocomina and Ophiopteris) previously considered to have a separate species in both the North and South hemispheres, and the third (Clarkcoma) diversifying in the southern Australian/New Zealand region. Our phylogeny, generated from one mitochondrial and two nuclear markers, revealed that Ophiopteris is sister to a mixed Ophiocomina/Clarkcoma clade. Ophiocomina was polyphyletic, with O. nigra and an undescribed species from the South Atlantic Ocean sister to a clade including Clarkcoma species and O. australis. The phylogeny also revealed a number of recently diverged lineages occurring within Clarkcoma, some of which are considered to be cryptic species due to the similarity in morphology combined with the apparent absence of interbreeding in a sympatric distribution, while the status of others is less certain. The phylogeny provides support for two transequatorial events in the group under study. A molecular clock analysis places both events in the middle to late Miocene. The analysis excludes a tectonic vicariance hypothesis for the antitropical distribution associated with the breakup of Pangaea and also excludes the hypothesis of more recent gene flow associated with Plio/Pleistocene glacial cycling. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Diversity distribution patterns of Chinese endemic seed plant species and their implications for conservation planning

    Science.gov (United States)

    Huang, Jihong; Huang, Jianhua; Lu, Xinghui; Ma, Keping

    2016-01-01

    Endemism is an important concept in biogeography and biodiversity conservation. China is one of the richest countries in biodiversity, with very high levels of plant endemism. In this study, we analysed the distribution patterns of diversity, the degree of differentiation, and the endemicity of Chinese endemic seed plants using the floristic unit as a basic spatial analysis unit and 11 indices. The analysis was based on distribution data of 24,951 native seed plant species (excluding subspecies and varieties) and 12,980 Chinese endemic seed plant species, which were sourced from both specimen records and published references. The distribution patterns of Chinese endemic flora were generally consistent but disproportionate across China for diversity, degree of differentiation and endemicity. The South Hengduan Mountains Subregion had the highest values for all indices. At the regional level, both the Hengduan Mountains and the Central China regions were highest in diversity and degrees of differentiation. However, both the rate of local endemic to native species and the rate of local to Chinese endemic species were highest in the Taiwan Region and the South Taiwan Region. The Hengduan Mountains Region and the Central China Region are two key conservation priority areas for Chinese endemic seed plants. PMID:27658845

  9. Moving Towards Dynamic Ocean Management: How Well Do Modeled Ocean Products Predict Species Distributions?

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Becker

    2016-02-01

    Full Text Available Species distribution models are now widely used in conservation and management to predict suitable habitat for protected marine species. The primary sources of dynamic habitat data have been in situ and remotely sensed oceanic variables (both are considered “measured data”, but now ocean models can provide historical estimates and forecast predictions of relevant habitat variables such as temperature, salinity, and mixed layer depth. To assess the performance of modeled ocean data in species distribution models, we present a case study for cetaceans that compares models based on output from a data assimilative implementation of the Regional Ocean Modeling System (ROMS to those based on measured data. Specifically, we used seven years of cetacean line-transect survey data collected between 1991 and 2009 to develop predictive habitat-based models of cetacean density for 11 species in the California Current Ecosystem. Two different generalized additive models were compared: one built with a full suite of ROMS output and another built with a full suite of measured data. Model performance was assessed using the percentage of explained deviance, root mean squared error (RMSE, observed to predicted density ratios, and visual inspection of predicted and observed distributions. Predicted distribution patterns were similar for models using ROMS output and measured data, and showed good concordance between observed sightings and model predictions. Quantitative measures of predictive ability were also similar between model types, and RMSE values were almost identical. The overall demonstrated success of the ROMS-based models opens new opportunities for dynamic species management and biodiversity monitoring because ROMS output is available in near real time and can be forecast.

  10. Assessing distributions of two invasive species of contrasting habits in future climate.

    Science.gov (United States)

    Panda, Rajendra Mohan; Behera, Mukunda Dev; Roy, Partha Sarathi

    2018-05-01

    Understanding the impact of climate change on species invasion is crucial for sustainable biodiversity conservation. Through this study, we try to answer how species differing in phenological cycles, specifically Cassia tora and Lantana camara, differ in the manner in which they invade new regions in India in the future climate. Since both species occupy identical niches, exploring their invasive potential in different climate change scenarios will offer critical insights into invasion and inform ecosystem management. We use three modelling protocols (i.e., maximum entropy, generalised linear model and generalised additive model) to predict the current distribution. Projections are made for both moderate (A1B) and extreme (A2) IPCC (Intergovernmental Panel on Climate Change) scenarios for the year 2050 and 2100. The study reveals that the distributions of C. tora (annual) and L. camara (perennial) would depend on the precipitation of the warmest quarter and moisture availability. C. tora may demonstrate physiological tolerance to the mean diurnal temperature range and L. camara to the solar radiation. C. tora may invade central India, while L. camara may invade the Western Himalaya, parts of the Eastern Himalaya and the Western Ghats. The distribution ranges of both species could shift in the northern and north-eastern directions in India, owing to changes in moisture availability. The possible alterations in precipitation regimes could lead to water stress, which might have cascading effects on species invasion. L. camara might adapt to climate change better compared with C. tora. This comparative analysis of the future distributions of two invasive plants with contrasting habits demonstrates that temporal complementarity would prevail over the competition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The interplay of various sources of noise on reliability of species distribution models hinges on ecological specialisation.

    Science.gov (United States)

    Soultan, Alaaeldin; Safi, Kamran

    2017-01-01

    Digitized species occurrence data provide an unprecedented source of information for ecologists and conservationists. Species distribution model (SDM) has become a popular method to utilise these data for understanding the spatial and temporal distribution of species, and for modelling biodiversity patterns. Our objective is to study the impact of noise in species occurrence data (namely sample size and positional accuracy) on the performance and reliability of SDM, considering the multiplicative impact of SDM algorithms, species specialisation, and grid resolution. We created a set of four 'virtual' species characterized by different specialisation levels. For each of these species, we built the suitable habitat models using five algorithms at two grid resolutions, with varying sample sizes and different levels of positional accuracy. We assessed the performance and reliability of the SDM according to classic model evaluation metrics (Area Under the Curve and True Skill Statistic) and model agreement metrics (Overall Concordance Correlation Coefficient and geographic niche overlap) respectively. Our study revealed that species specialisation had by far the most dominant impact on the SDM. In contrast to previous studies, we found that for widespread species, low sample size and low positional accuracy were acceptable, and useful distribution ranges could be predicted with as few as 10 species occurrences. Range predictions for narrow-ranged species, however, were sensitive to sample size and positional accuracy, such that useful distribution ranges required at least 20 species occurrences. Against expectations, the MAXENT algorithm poorly predicted the distribution of specialist species at low sample size.

  12. Species sensitivity distributions in a context of practical applications for risk-based decisions

    Energy Technology Data Exchange (ETDEWEB)

    Posthuma, L.; Traas, T.P.; Roelofs, W.; Winterse, A.; Zwart, D. de; Meent, D. van de [RIVM, Bilthoven (Netherlands)

    2003-07-01

    Different biological species clearly show different sensitivities to toxic compounds present in their habitat. The absence of differences in sensitivity would entail an 'all nothing' response, with all species responding similarly to pollution. Given the sensitivity variation, however, some species show adverse effects, and others flourish. In this sense, variation is 'music for ecotoxicologists'. But it also is a nuisance: ecotoxicologists need to handle the vast diversity of sensitivities in Ecological Risk Assessment (ERA). This contribution addresses a pragmatic, versatile, statistics-based concept to address species sensitivity differences, and shows options for application. In the 1980s, ecotoxicologists have coined the term 'Species Sensitivity Distributions' (SSDs) for the statistical descriptions that can be applied to address sensitivity variation. An SSD is a Probability Density Function (usually bell-shaped) or Cumulative Distribution Function (sigmoid), that relates the environmental concentration (x) to 'risk' (y). Since their original description and use, the concept was further developed, criticised, and tailored to various policy or assessment problems. (orig.)

  13. Physico-chemical thresholds in the distribution of fish species among French lakes

    Directory of Open Access Journals (Sweden)

    Roubeix Vincent

    2017-01-01

    Full Text Available The management of lakes requires the definition of physico-chemical thresholds to be used for ecosystem preservation or restoration. According to the European Water Framework Directive, the limits between physico-chemical quality classes must be set consistently with biological quality elements. One way to do this consists in analyzing the response of aquatic communities to environmental gradients across monitoring sites and in identifying ecological community thresholds, i.e. zones in the gradients where the species turnover is the highest. In this study, fish data from 196 lakes in France were considered to derive ecological thresholds using the multivariate method of gradient forest. The analysis was performed on 25 species and 36 environmental parameters. The results revealed the highest importance of maximal water temperature in the distribution of fish species. Other important parameters included geographical factors, dissolved organic carbon concentration and water transparency, while nutrients appeared to have low influence. In spite of the diversity of species responses to the gradients, community thresholds were detected in the gradients of the most important physico-chemical parameters and of total phosphorus and nitrate concentrations as well. The thresholds identified in such macroecological study may highlight new patterns of species natural distribution and improve niche characterization. Moreover, when factors that may be influenced by human activities are involved, the thresholds could be used to set environmental standards for lake preservation.

  14. Climate and soil type together explain the distribution of microendemic species in a biodiversity hotspot.

    Directory of Open Access Journals (Sweden)

    Romain Nattier

    Full Text Available The grasshopper genus Caledonula, endemic to New Caledonia, was studied to understand the evolution of species distributions in relation to climate and soil types. Based on a comprehensive sampling of 80 locations throughout the island, the genus was represented by five species, four of which are new to science, of which three are described here. All the species have limited distributions in New Caledonia. Bioclimatic niche modelling shows that all the species were found in association with a wet climate and reduced seasonality, explaining their restriction to the southern half of the island. The results suggest that the genus was ancestrally constrained by seasonality. A molecular phylogeny was reconstructed using two mitochondrial and two nuclear markers. The partially resolved tree showed monophyly of the species found on metalliferous soils, and molecular dating indicated a rather recent origin for the genus. Adaptation to metalliferous soils is suggested by both morphological changes and radiation on these soils. The genus Caledonula is therefore a good model to understand the origin of microendemism in the context of recent and mixed influences of climate and soil type.

  15. Climate and soil type together explain the distribution of microendemic species in a biodiversity hotspot.

    Science.gov (United States)

    Nattier, Romain; Grandcolas, Philippe; Pellens, Roseli; Jourdan, Hervé; Couloux, Arnaud; Poulain, Simon; Robillard, Tony

    2013-01-01

    The grasshopper genus Caledonula, endemic to New Caledonia, was studied to understand the evolution of species distributions in relation to climate and soil types. Based on a comprehensive sampling of 80 locations throughout the island, the genus was represented by five species, four of which are new to science, of which three are described here. All the species have limited distributions in New Caledonia. Bioclimatic niche modelling shows that all the species were found in association with a wet climate and reduced seasonality, explaining their restriction to the southern half of the island. The results suggest that the genus was ancestrally constrained by seasonality. A molecular phylogeny was reconstructed using two mitochondrial and two nuclear markers. The partially resolved tree showed monophyly of the species found on metalliferous soils, and molecular dating indicated a rather recent origin for the genus. Adaptation to metalliferous soils is suggested by both morphological changes and radiation on these soils. The genus Caledonula is therefore a good model to understand the origin of microendemism in the context of recent and mixed influences of climate and soil type.

  16. Effects of pesticides on soil invertebrates in laboratory studies: A review and analysis using species sensitivity distributions

    NARCIS (Netherlands)

    Frampton, G.K.; Jänsch, S.; Scott-Fordsmand, J.J.; Römbke, J.; Brink, van den P.J.

    2006-01-01

    Species sensitivity distributions (SSD) and 5% hazardous concentrations (HC5) are distribution-based approaches for assessing environmental risks of pollutants. These methods have potential for application in pesticide risk assessments, but their applicability for assessing pesticide risks to soil

  17. Species abundance distributions in neutral models with immigration or mutation and general lifetimes.

    Science.gov (United States)

    Lambert, Amaury

    2011-07-01

    We consider a general, neutral, dynamical model of biodiversity. Individuals have i.i.d. lifetime durations, which are not necessarily exponentially distributed, and each individual gives birth independently at constant rate λ. Thus, the population size is a homogeneous, binary Crump-Mode-Jagers process (which is not necessarily a Markov process). We assume that types are clonally inherited. We consider two classes of speciation models in this setting. In the immigration model, new individuals of an entirely new species singly enter the population at constant rate μ (e.g., from the mainland into the island). In the mutation model, each individual independently experiences point mutations in its germ line, at constant rate θ. We are interested in the species abundance distribution, i.e., in the numbers, denoted I(n)(k) in the immigration model and A(n)(k) in the mutation model, of species represented by k individuals, k = 1, 2, . . . , n, when there are n individuals in the total population. In the immigration model, we prove that the numbers (I(t)(k); k ≥ 1) of species represented by k individuals at time t, are independent Poisson variables with parameters as in Fisher's log-series. When conditioning on the total size of the population to equal n, this results in species abundance distributions given by Ewens' sampling formula. In particular, I(n)(k) converges as n → ∞ to a Poisson r.v. with mean γ/k, where γ : = μ/λ. In the mutation model, as n → ∞, we obtain the almost sure convergence of n (-1) A(n)(k) to a nonrandom explicit constant. In the case of a critical, linear birth-death process, this constant is given by Fisher's log-series, namely n(-1) A(n)(k) converges to α(k)/k, where α : = λ/(λ + θ). In both models, the abundances of the most abundant species are briefly discussed.

  18. Citizen science contributes to our knowledge of invasive plant species distributions

    Science.gov (United States)

    Crall, Alycia W.; Jarnevich, Catherine S.; Young, Nicholas E.; Panke, Brendon; Renz, Mark; Stohlgren, Thomas

    2015-01-01

    Citizen science is commonly cited as an effective approach to expand the scale of invasive species data collection and monitoring. However, researchers often hesitate to use these data due to concerns over data quality. In light of recent research on the quality of data collected by volunteers, we aimed to demonstrate the extent to which citizen science data can increase sampling coverage, fill gaps in species distributions, and improve habitat suitability models compared to professionally generated data sets used in isolation. We combined data sets from professionals and volunteers for five invasive plant species (Alliaria petiolata, Berberis thunbergii, Cirsium palustre, Pastinaca sativa, Polygonum cuspidatum) in portions of Wisconsin. Volunteers sampled counties not sampled by professionals for three of the five species. Volunteers also added presence locations within counties not included in professional data sets, especially in southern portions of the state where professional monitoring activities had been minimal. Volunteers made a significant contribution to the known distribution, environmental gradients sampled, and the habitat suitability of P. cuspidatum. Models generated with professional data sets for the other four species performed reasonably well according to AUC values (>0.76). The addition of volunteer data did not greatly change model performance (AUC > 0.79) but did change the suitability surface generated by the models, making them more realistic. Our findings underscore the need to merge data from multiple sources to improve knowledge of current species distributions, and to predict their movement under present and future environmental conditions. The efficiency and success of these approaches require that monitoring efforts involve multiple stakeholders in continuous collaboration via established monitoring networks.

  19. Current Knowledge of Leishmania Vectors in Mexico: How Geographic Distributions of Species Relate to Transmission Areas

    Science.gov (United States)

    González, Camila; Rebollar-Téllez, Eduardo A.; Ibáñez-Bernal, Sergio; Becker-Fauser, Ingeborg; Martínez-Meyer, Enrique; Peterson, A. Townsend; Sánchez-Cordero, Víctor

    2011-01-01

    Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological niches of nine sand fly species and projected niches to estimate potential distributions by using known occurrences, environmental coverages, and the algorithms GARP and Maxent. All vector species were distributed in areas with known recurrent transmission, except for Lu. diabolica, which appeared to be related only to areas of occasional transmission in northern Mexico. The distribution of Lu. o. olmeca does not overlap with all reported cutaneous leishmaniasis cases, suggesting that Lu. cruciata and Lu. shannoni are likely also involved as primary vectors in those areas. Our study provides useful information of potential risk areas of leishmaniasis transmission in Mexico. PMID:22049037

  20. Transferability of species distribution models: a functional habitat approach for two regionally threatened butterflies.

    Science.gov (United States)

    Vanreusel, Wouter; Maes, Dirk; Van Dyck, Hans

    2007-02-01

    Numerous models for predicting species distribution have been developed for conservation purposes. Most of them make use of environmental data (e.g., climate, topography, land use) at a coarse grid resolution (often kilometres). Such approaches are useful for conservation policy issues including reserve-network selection. The efficiency of predictive models for species distribution is usually tested on the area for which they were developed. Although highly interesting from the point of view of conservation efficiency, transferability of such models to independent areas is still under debate. We tested the transferability of habitat-based predictive distribution models for two regionally threatened butterflies, the green hairstreak (Callophrys rubi) and the grayling (Hipparchia semele), within and among three nature reserves in northeastern Belgium. We built predictive models based on spatially detailed maps of area-wide distribution and density of ecological resources. We used resources directly related to ecological functions (host plants, nectar sources, shelter, microclimate) rather than environmental surrogate variables. We obtained models that performed well with few resource variables. All models were transferable--although to different degrees--among the independent areas within the same broad geographical region. We argue that habitat models based on essential functional resources could transfer better in space than models that use indirect environmental variables. Because functional variables can easily be interpreted and even be directly affected by terrain managers, these models can be useful tools to guide species-adapted reserve management.

  1. Mechanistic species distribution modelling as a link between physiology and conservation.

    Science.gov (United States)

    Evans, Tyler G; Diamond, Sarah E; Kelly, Morgan W

    2015-01-01

    Climate change conservation planning relies heavily on correlative species distribution models that estimate future areas of occupancy based on environmental conditions encountered in present-day ranges. The approach benefits from rapid assessment of vulnerability over a large number of organisms, but can have poor predictive power when transposed to novel environments and reveals little in the way of causal mechanisms that define changes in species distribution or abundance. Having conservation planning rely largely on this single approach also increases the risk of policy failure. Mechanistic models that are parameterized with physiological information are expected to be more robust when extrapolating distributions to future environmental conditions and can identify physiological processes that set range boundaries. Implementation of mechanistic species distribution models requires knowledge of how environmental change influences physiological performance, and because this information is currently restricted to a comparatively small number of well-studied organisms, use of mechanistic modelling in the context of climate change conservation is limited. In this review, we propose that the need to develop mechanistic models that incorporate physiological data presents an opportunity for physiologists to contribute more directly to climate change conservation and advance the field of conservation physiology. We begin by describing the prevalence of species distribution modelling in climate change conservation, highlighting the benefits and drawbacks of both mechanistic and correlative approaches. Next, we emphasize the need to expand mechanistic models and discuss potential metrics of physiological performance suitable for integration into mechanistic models. We conclude by summarizing other factors, such as the need to consider demography, limiting broader application of mechanistic models in climate change conservation. Ideally, modellers, physiologists and

  2. Species composition, distribution and abundance of chaetodontidae along reef transects in the Flores Sea

    Science.gov (United States)

    Adrim, Mohammad; Hutomo, Malikusworo

    Observations on chaetodontid fishes were made by applying a visual census technique at 13 coral reef locations in the Flores Sea region in October and November 1984. These observations were made along 50 m transect lines, parallel to the shore or the reef edge at depths between 3 to 12 m. Twenty-three species of Chaetodontidae were observed, representing three genera: Chaetodon (20 species), Heniochus (2 species) and Forcipiger (1 species). Chaetodon kleini, C. trifasciatus, C. melannotus and C. baronessa proved to be the most abundant species, and among them C. kleini and C. trifasciatus were the most widely distributed ones. Chaetodon semeion and C. mertensi were the rarest species. The greatest number of individuals (77) was counted at station 4.268 near Tanjung Burung, Sumbawa, while the greatest number of species (14) was observed at station 4.257, north of Komodo. The lowest number of individuals (17) was counted at station 4.175 near P. Bahuluang, Salayer, while station 4.251 near Teluk Slawi, Komodo, was inhabited by the smallest numbver of species (2). Numerical classification by using the Bray Curtis dissimilarity index resulted in three groups of entities. The first group was characterized by predomination of C. kleini and the second by predomination of C. melannotus. The third one was a loose group not characterized by any predominant species. The analyses indicated that the similarities of the chaetodontid communities between locations are not related to the distance between them, but rather to habitat conditions. For example predomination of C. melannotus is strongly related to the predomination of soft coral. Compared to other areas of Indonesia, e.g. Bali, Seribu Islands, Batam, Sunda Strait, and Ambon Bay, the Flores Sea reefs have a more abundant and more diverse chaetodontid fauna.

  3. Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan.

    Science.gov (United States)

    Zaidi, Farrah; Fatima, Syeda Hira; Khisroon, Muhammad; Gul, Ayesha

    2016-10-01

    North West Pakistan (NWP) is characterized by four eco-zones: Northern Montane Region, North Western Hills, Submontane Region and Indus Plains. Present study identified 1037 cases of traumatic myiasis in the region during 2012-2015. Screw worm larvae were classified as 12 species: Chrysomya bezziana (Villeneuve), Chryomya megacephala (Fabricius), Chrysomya rufifacies (Macquart), Lucilia cuprina (Wiedemann), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Lucilia porphyrina (Walker), Hemipyrellia ligguriens (Wiedemann), Calliphora vicina (Robineau-Desvoidy), Wohlfahrtia magnifica (Schiner), Sarcophaga crassipalpalis (Macquart), Sarchophaga species. Among these C. bezziana, L. cuprina and W. magnifica with approximately 882 case reports were the principal agents of traumatic myiasis. The species W. magnifica is a first report from Pakistan. In order to investigate spatial distribution of these dominant species we used MaxEnt niche model. Our results revealed a well-established occurrence of C. bezziana and L. cuprina in the four eco-regions while W. magnifica is currently contained in the Submontane Region. Several hot spot areas of infestation were detected all characterized by high human population density showing synanthropic nature of these species. Wohlfahrtia magnifica was excluded from Northern Montane Region with severe winters and Southern Indus Plains with harsh summers revealing that invasive species are initially sensitive to extreme of temperatures. Presence of L. cuprina in the wet areas of North Humid Belt (Maximum annual precipitation: 1641mm) depicted a moisture preference of the species. In perspective of changing climate and future predictions of severe events such as droughts and flooding in NWP, W. magnifica can potentially alter the species composition. Considering these findings in an eco-geographically dynamic region of Pakistan we predict that two factors (1) Growing human population (2) Climatic conditions, equally contribute to range

  4. Distribution Pattern of Seahorse species (Genus: Hippocampus in Tamilnadu and Kerala Coasts of India

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    Aaron Premnath LIPTON

    2013-02-01

    Full Text Available The survey along the Tamilnadu and Kerala coats of India reveled that six species of seahors (Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H. trimaculatus were distributed with different density. Out of the six species, H. fuscus, H. kuda and H. trimaculatus, were the commonly available species in all the observed areas. In Palk Bay, H. kuda was the dominant species constituting 49.10% of the total seahorses encountered. Hippocampus trimaculatus was the second dominant species which accounting 39.28%. The Gulf of Mannar region also most abounded with H. kuda (68.98% followed by H. trimaculatus (20.80%, H. fuscus (9.80%, H. kelloggi (2.23% and H. histrix (0.37%. In Kerala coast, H. trimaculatus was the dominant species (79.68% followed by H. kuda (9.89%, H. kelloggi (8.33% and H. fuscus (2.08%. To infer the variation of six seahorse species the morphometric and meristic characters were analysed. The important morphometric and meristic characters are trunk rings, tail rings, pectoral and dorsal fin rays, trunk length, tail length, coronet height, head length, snout length, snout depth and head depth. Variation in overall body shape, relative snout length, coronet height, number of tail ring was sufficient to separate the specimens to Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H.trimaculatus. The species density and diversity depends on the habitat and biogeography of those areas. Majority of seahorse fishing in Tamilnadu was by shrimp trawl, by-catch and very few target catch by divers also seen in some villages of Palk Bay and Gulf of Mannar region. The shrimp trawl by-catch only bringing more H. trimaculatus than the other species in Kerala coasts.

  5. Collision risks at sea: species composition and altitude distributions of birds in Danish offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Blew, J.; Hoffmann, M.; Nehls, G. [BioConsult SH (Germany)

    2007-07-01

    This study investigates the collision risks of birds in operating offshore wind farms, focussing on all bird species present in the direct vicinity of the wind farms, their altitude distribution and reactions. The project was conducted jointly by BioConsult SH and the University of Hamburg in the two Danish offshore wind farms Horns Rev (North Sea) and Nysted (Baltic Sea) in the framework of a Danish-German cooperation and financed by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). Data were collected between March 2005 and November 2006, using a ship anchored at the edge of the offshore wind farms. In this way, bird species of all sizes could be considered. Daytime observations yielded data on species composition, flight routes and potential reactions of the birds. Radar observations provided altitude distributions inside and outside the wind farm area and also reactions. The results shall help to further describe and assess the collision risk of different species groups. Since data analysis is still running, exemplary results will be presented here. 114 species have been recorded in Nysted and 99 in Horns Rev, approximately 65% of which have been observed inside the wind farm areas. Migrating birds seem to avoid flying into the wind farms, whereas individuals present in the areas for extended time periods utilize areas within the wind farms. While a barrier effect exists for species on migration, resident species probably have a higher collision risk. Raptors migrating during daylight frequently enter the wind farm area on their flight routes, correcting their flight paths in order to avoid collisions. Radar results show that during times of intensive migration, the proportion of birds flying at high altitudes and thus above windmill height is higher than in times of low migration intensity. Consequently, there is a lower proportion of migrating birds flying within the risk area. Data will be further analysed to

  6. Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions.

    Science.gov (United States)

    Garnica, Sigisfredo; Spahn, Philipp; Oertel, Bernhard; Ammirati, Joseph; Oberwinkler, Franz

    2011-07-19

    Cortinarius species in section Calochroi display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1) C. arcuatorum, 2) C. aureofulvus, 3) C. elegantior and 4) C. napus, from populations distributed throughout the Old World, and portions of the New World (Central- and North America) based on genetic variation of 154 haplotype internal transcribed spacer (ITS) sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification. Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in C. arcuatorum and C. elegantior, while C. aureofulvus showed considerably less population structure and C. napus lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within C. arcuatorum, C. aureofulvus and C. elegantior show little or no morphological differentiation, whereas in C. napus there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of C. albobrunnoides and C. albobrunnoides var. violaceovelatus were identical to one another and are treated as one species with a wider range of geographic distribution under C. napus. Our results indicate that each of the Calochroi species has undergone a relatively independent evolutionary history, hypothesised as follows: 1) a widely distributed ancestral population of C. arcuatorum diverged into distinctive sympatric populations in the New World; 2) two divergent lineages in C

  7. Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions

    Directory of Open Access Journals (Sweden)

    Ammirati Joseph

    2011-07-01

    Full Text Available Abstract Background Cortinarius species in section Calochroi display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1 C. arcuatorum, 2 C. aureofulvus, 3 C. elegantior and 4 C. napus, from populations distributed throughout the Old World, and portions of the New World (Central- and North America based on genetic variation of 154 haplotype internal transcribed spacer (ITS sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification. Results Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in C. arcuatorum and C. elegantior, while C. aureofulvus showed considerably less population structure and C. napus lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within C. arcuatorum, C. aureofulvus and C. elegantior show little or no morphological differentiation, whereas in C. napus there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of C. albobrunnoides and C. albobrunnoides var. violaceovelatus were identical to one another and are treated as one species with a wider range of geographic distribution under C. napus. Conclusions Our results indicate that each of the Calochroi species has undergone a relatively independent evolutionary history, hypothesised as follows: 1 a widely distributed ancestral population of C. arcuatorum diverged into distinctive sympatric

  8. Biodiversity, Distributions and Adaptations of Arctic Species in the Context of Environmental Change

    Energy Technology Data Exchange (ETDEWEB)

    Callaghan, Terry V. [Abisko Scientific Research Station, Abisko (Sweden); Bjoern, Lars Olof [Lund Univ. (Sweden). Dept. of Cell and Organism Biology; Chernov, Yuri [Russian Academy of Sciences, Moscow (Russian Federation). A.N. Severtsov Inst. of Evolutionary Morphology and Animal Ecology] (and others)

    2004-11-01

    adapted to the Arctic's climate: some can metabolize at temperatures down to -39 deg C. Cyanobacteria and algae have a wide range of adaptive strategies that allow them to avoid, or at least minimize UV injury. Microorganisms can tolerate most environmental conditions and they have short generation times which can facilitate rapid adaptation to new environments. In contrast, Arctic plant and animal species are very likely to change their distributions rather than evolve significantly in response to warming.

  9. The Analysis of Tree Species Distribution Information Extraction and Landscape Pattern Based on Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Yi Zeng

    2017-08-01

    Full Text Available The forest ecosystem is the largest land vegetation type, which plays the role of unreplacement with its unique value. And in the landscape scale, the research on forest landscape pattern has become the current hot spot, wherein the study of forest canopy structure is very important. They determines the process and the strength of forests energy flow, which influences the adjustments of ecosystem for climate and species diversity to some extent. The extraction of influencing factors of canopy structure and the analysis of the vegetation distribution pattern are especially important. To solve the problems, remote sensing technology, which is superior to other technical means because of its fine timeliness and large-scale monitoring, is applied to the study. Taking Lingkong Mountain as the study area, the paper uses the remote sensing image to analyze the forest distribution pattern and obtains the spatial characteristics of canopy structure distribution, and DEM data are as the basic data to extract the influencing factors of canopy structure. In this paper, pattern of trees distribution is further analyzed by using terrain parameters, spatial analysis tools and surface processes quantitative simulation. The Hydrological Analysis tool is used to build distributed hydrological model, and corresponding algorithm is applied to determine surface water flow path, rivers network and basin boundary. Results show that forest vegetation distribution of dominant tree species present plaque on the landscape scale and their distribution have spatial heterogeneity which is related to terrain factors closely. After the overlay analysis of aspect, slope and forest distribution pattern respectively, the most suitable area for stand growth and the better living condition are obtained.

  10. Occurrence of 3 Bordetella species during an outbreak of cough illness in Ohio: epidemiology, clinical features, laboratory findings and antimicrobial susceptibility.

    Science.gov (United States)

    Spicer, Kevin B; Salamon, Doug; Cummins, Carol; Leber, Amy; Rodgers, Loren E; Marcon, Mario J

    2014-07-01

    An increase in laboratory diagnosis of pertussis was noted in central Ohio during 2010. Diagnosis was made using a polymerase chain reaction assay targeting the multicopy insertion sequence IS481, which is found in both Bordetella pertussis (Bp) and Bordetella holmesii (Bh). An increase in specimens testing positive for Bordetella parapertussis (Bpp) using insertion sequence IS1001 was also noted. Nasopharyngeal swab specimens submitted April 1, 2010, to March 31, 2011, were tested using a multiplex polymerase chain reaction assay for Bp/Bh (IS481) and Bpp followed by singleplex assays for Bp and Bh. A subgroup of specimens was also cultured for Bordetella species, and antimicrobial susceptibility testing was performed on recovered organisms. Demographic and clinical features were compared for patients with Bp, Bh and Bpp. Of 520 IS481-positive specimens, 214 (41.1%) were positive for Bp, 79 (15.2%) were positive for Bh and 5 (1.0%) were positive for both Bp and Bh; 222 (42.7%) were negative for both targets. An additional 220 specimens were positive for Bpp. Among a sample of 155 IS481-positive specimens, 40, 15 and 0 were culture positive for Bp, Bh and Bpp, respectively. Among a sample of 55 BparaIS1001-positive (Bpp) specimens, 22, 0 and 0 were culture positive for Bpp, Bp and Bh, respectively. All Bordetella species were susceptible to macrolide antibiotics. Patients with Bh were older than patients with Bp, who were older than those positive for Bpp (mean ages: 12.0, 8.0 and 4.2 years, respectively; P Bpp and 100 negative for Bordetella species), but did not differ statistically among the groups (χ = 5.1, P = 0.17). All 3 Bordetella species, Bp, Bh and Bpp, were detected during on outbreak of pertussis-like cough illness. There were noted differences in age and seasonality, but clinical features at the time of presentation did not allow clear differentiation of these infections. All Bordetella species recovered from culture and tested were susceptible in

  11. Maxent modeling for predicting the potential geographical distribution of two peony species under climate change.

    Science.gov (United States)

    Zhang, Keliang; Yao, Linjun; Meng, Jiasong; Tao, Jun

    2018-09-01

    Paeonia (Paeoniaceae), an economically important plant genus, includes many popular ornamentals and medicinal plant species used in traditional Chinese medicine. Little is known about the properties of the habitat distribution and the important eco-environmental factors shaping the suitability. Based on high-resolution environmental data for current and future climate scenarios, we modeled the present and future suitable habitat for P. delavayi and P. rockii by Maxent, evaluated the importance of environmental factors in shaping their distribution, and identified distribution shifts under climate change scenarios. The results showed that the moderate and high suitable areas for P. delavayi and P. rockii encompassed ca. 4.46×10 5 km 2 and 1.89×10 5 km 2 , respectively. Temperature seasonality and isothermality were identified as the most critical factors shaping P. delavayi distribution, and UVB-4 and annual precipitation were identified as the most critical for shaping P. rockii distribution. Under the scenario with a low concentration of greenhouse gas emissions (RCP2.6), the range of both species increased as global warming intensified; however, under the scenario with higher concentrations of emissions (RCP8.5), the suitable habitat range of P. delavayi decreased while P. rockii increased. Overall, our prediction showed that a shift in distribution of suitable habitat to higher elevations would gradually become more significant. The information gained from this study should provide a useful reference for implementing long-term conservation and management strategies for these species. Copyright © 2018. Published by Elsevier B.V.

  12. Morphology, Diet Composition, Distribution and Nesting Biology of Four Lark Species in Mongolia

    Directory of Open Access Journals (Sweden)

    Galbadrakh Mainjargal

    2013-12-01

    Full Text Available We aimed to enhance existing knowledge of four lark species (Mongolian lark , Horned lark, Eurasian skylark, and Lesser short-toed lark, with respect to nesting biology, distribution, and diet, using long-term dataset collected during 2000–2012. Nest and egg measurements substantially varied among species. For pooled data across species, the clutch size averaged 3.72 ± 1.13 eggs and did not differ among larks. Body mass of nestlings increased signi fi cantly with age at weighing. Daily increase in body mass of lark nestlings ranged between 3.09 and 3.89 gram per day. Unsurprisingly, the majority of lark locations occurred in steppe ecosystems, followed by human created systems; whereas only 1.8% of the pooled locations across species were observed in forest ecosystem. Diet composition did not vary among species in the proportions of major food categories consumed. The most commonly occurring food items were invertebrates and frequently consumed were being beetles (e.g. Coleoptera: Carabidae, Scarabaeidae, and Curculionidae and grasshoppers (e.g. Orthoptera: Acrididae, and their occurrences accounted for 63.7% of insect related food items. Among the fi ve morphological traits we measured, there were signi fi cant differences in wing span, body mass, bill, and tarsus; however tail lengths did not differ across four species.

  13. [Distribution of Candida species in vaginal specimens and evaluation of CHROMagar Candida medium].

    Science.gov (United States)

    Gültekin, Berna; Yazici, Vesile; Aydin, Neriman

    2005-07-01

    Identification of Candida species is important to guide treatment in vulvovaginal candidiasis which is seen frequently and needs long-term therapy due to recurrence. The aim of this study was to determine the species distribution of Candida isolated from vaginal specimens and evaluation of CHROMagar Candida medium in the laboratory diagnosis. Samples from 80 patients who were clinically diagnosed as vaginitis have been analysed in our laboratory. Colonies appeared on CHROMagar Candida media after 48 hours of incubation at 35 degrees C were evaluated for their colors and characteristics. Candida strains were identified by germ tube test, growth on corn meal Tween 80 agar and when necessary also by API 20 C AUX commercial kit. A total of 84 Candida strains were isolated from 80 patients. Two different Candida species have been isolated from four (5%) of the samples. Among Candida strains isolated, 45 (53.6%) were C. albicans, 29 (34.5%) C. glabrata, 7 (8.3%) C. krusei, and 3 (3.6%) C. kefyr. All of the C. albicans and six of the seven C. krusei isolates have been identified correctly by CHROMagar Candida medium. These results showed that C. albicans is still the most frequently isolated species from vaginal samples. It was concluded that CHROMagar Candida medium is useful for identification of colonies due to frequently seen Candida species and also in differentiation of multiple Candida species grown on the same culture.

  14. DISTRIBUTION AND DIVERSITY OF FUSARIUM SPECIES ASSOCIATED WITH GRASSES IN TEN STATES THROUGHOUT PENINSULAR MALAYSIA

    Directory of Open Access Journals (Sweden)

    NUR AIN IZZATI, M.Z

    2009-01-01

    Full Text Available Fusarium is one of the important genera associated with grasses as saprophytes, endophytes and pathogens. A study was carried out on distribution and diversity of Fusarium species associated with two groups of grasses in 10 states throughout Peninsular Malaysia i.e. agricultural grasses (Oryza sativa and Saccharum officinarum and non-agricultural grasses (Axonopus compressus, Centhotheca lappacea, Chloris barbata, Crysopogon aciculatus, Cyanadon dactylon, Dactyloctenium aegyptium, Digitaria ciliaris, Echinochloa colona, Eleusine indica, Eragrostis amabilis, Eragrostis malayana, Eragrostis uniloides, Ischaemum magnum, Panicum brevifolium, Panicum millaneum, Panicum repens, Paspalum commersonii, Paspalum conjugatum, Paspalum orbiculare, Pennisetum purpureum, Sacciolepis indica, Sporobolus diander and Sporobolus indicus. A total of 474 isolates were single-spored and identified by morphological characteristics. F. semitectum was frequently isolated (23.6%, followed by F. sacchari and F. fujikuroi with 15.4% and 14.6%, respectively. The other nine species were F. solani (10.3%, F. proliferatum (8.9%, F. oxysporum (7.4%, F. subglutinans (6.5%, F. equiseti (5.5%, F. verticillioides (3.4%, F. compactum (2.5%, F. chlamydosporum (1.1% and F. longipes (0.8%. Based on the Shannon-Weiner Index, F. solani was the highest (H' = 2.62 isolated from grasses. Species of Fusarium from O. sativa were widely diverse with 11 species, followed by non-agricultural grasses with nine species and S. officinarum with only six species. This is the first report on diversity of Fusarium associated with grasses in Malaysia.

  15. Modelling the spatial distribution of the nuisance mosquito species Anopheles plumbeus (Diptera: Culicidae) in the Netherlands.

    Science.gov (United States)

    Ibañez-Justicia, Adolfo; Cianci, Daniela

    2015-05-01

    Landscape modifications, urbanization or changes of use of rural-agricultural areas can create more favourable conditions for certain mosquito species and therefore indirectly cause nuisance problems for humans. This could potentially result in mosquito-borne disease outbreaks when the nuisance is caused by mosquito species that can transmit pathogens. Anopheles plumbeus is a nuisance mosquito species and a potential malaria vector. It is one of the most frequently observed species in the Netherlands. Information on the distribution of this species is essential for risk assessments. The purpose of the study was to investigate the potential spatial distribution of An. plumbeus in the Netherlands. Random forest models were used to link the occurrence and the abundance of An. plumbeus with environmental features and to produce distribution maps in the Netherlands. Mosquito data were collected using a cross-sectional study design in the Netherlands, from April to October 2010-2013. The environmental data were obtained from satellite imagery and weather stations. Statistical measures (accuracy for the occurrence model and mean squared error for the abundance model) were used to evaluate the models performance. The models were externally validated. The maps show that forested areas (centre of the Netherlands) and the east of the country were predicted as suitable for An. plumbeus. In particular high suitability and high abundance was predicted in the south-eastern provinces Limburg and North Brabant. Elevation, precipitation, day and night temperature and vegetation indices were important predictors for calculating the probability of occurrence for An. plumbeus. The probability of occurrence, vegetation indices and precipitation were important for predicting its abundance. The AUC value was 0.73 and the error in the validation was 0.29; the mean squared error value was 0.12. The areas identified by the model as suitable and with high abundance of An. plumbeus, are

  16. Density, size and distribution of stomata in 35 rainforest trees species in Central Amazonia

    OpenAIRE

    Miguel Angelo Branco Camargo; Ricardo Antonio Marenco

    2011-01-01

    Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five ...

  17. Density, size and distribution of stomata in 35 rainforest tree species in Central Amazonia

    OpenAIRE

    Camargo, Miguel Angelo Branco; Marenco, Ricardo Antonio

    2011-01-01

    Stomata are turgor-operated valves that control water loss and CO2 uptake during photosynthesis, and thereby water relation and plant biomass accumulation is closely related to stomatal functioning. The aims of this work were to document how stomata are distributed on the leaf surface and to determine if there is any significant variation in stomatal characteristics among Amazonian tree species, and finally to study the relationship between stomatal density (S D) and tree height. Thirty five ...

  18. Distributional patterns of the South American species of Hyalella (Amphipoda: Hyalellidae)

    OpenAIRE

    De los Ríos-Escalante, Patricio; Morrone, Juan J; Rivera, Reinaldo

    2012-01-01

    Distributional patterns of the South American species of the freshwater amphipod genus Hyalella were analysed using a panbiogeographic approach. Five generalized tracks were found: (1) northern Andes to Lake Titicaca (H. dielaii, H. meinerti, H. dybowskii, H.jelskii, H. lubominsky, and H. pauperocavae; (2) lake Titicaca (H. armata, H. cuprea, H. latinamus, H. lucifugax, H. montforti, H. neveulemairei, H. robusta, H. tiwanaku, H. simplex simplex, and H. solida); (3) central Andes (H. fossamanc...

  19. Species distributions and climate change - linking the past and the future

    DEFF Research Database (Denmark)

    Levinsky, Irina

    Climate change is predicted to have a marked impact on biodiversity, and changes in the distributions of numerous species have already been correlated with ongoing climate change. Climatic oscillations, however, were also the rule during the Pleistocene, and a look to the past may therefore shed ...... conditions during the Last Glacial Maximum, explore surrogates for the dispersal ability of African starlings and critically assess the tools I use and the assumptions behind them....

  20. New distribution data of some Pontic and submediterranean plant species in Serbia

    Directory of Open Access Journals (Sweden)

    Tomović Gordana M.

    2003-01-01

    Full Text Available We present here the distribution of 11 rare Pontic and submediterranean plant species in Serbia based on field research, herbarium and literature data. These taxa were mapped on 10 x 10 km2 UTM grid. The following taxa were analyzed: Dianthus pinifolius Sibth. & Sm., Doronicum hungaricum Reichenb. fil., Sedum stefco Stefanov, Sempervivum zeleborii Schott, Trifolium pignantii Fauche & Chaub., Ranunculus illyricus L., Potentilla chrysantha Trev., Prunus tenella Batsch, Saxifraga bulbifera L., Linaria pelisseriana (L Miller and Gagea bohemica (Zausc Schul. & Schul.

  1. Prevalence and distribution of Eimeria species in broiler chicken farms of different capacities

    Science.gov (United States)

    Györke, Adriana; Pop, Loredana; Cozma, Vasile

    2013-01-01

    We conducted a survey in broiler farms from Romania to establish prevalence and distribution of Eimeria species using single PCR assay. We found Eimeria spp. in 21 (91%) out of 23 flocks, and in 11 (92%) out of 12 farms. Four species of Eimeria were identified: E. acervulina (21/23; 91%), E. tenella (14/23; 61%), E. maxima (5/23; 22%) and E. praecox (3/23; 13%). Infection with a single species (E. acervulina) was detected in 6 (26%) infected flocks originated from large farms. Mixed infections were found in 15 (65%) flocks and the most prevalent combination was E. acervulina + E. tenella (8/23; 35%). Four flocks (17%) harboured mixed infection with E. acervulina + E. tenella + E. maxima. E. acervulina was significantly more prevalent in flocks that received ionophores as anticoccidial feed additives. PMID:24309007

  2. Species distributions and climate change:current patterns and future scenarios for biodiversity

    DEFF Research Database (Denmark)

    Hof, Christian

    by shifts of their distributional ranges, which affects the spatial patterns of species richness and turnover. Global temperatures are projected to rise by 1.8 - 4°C until the end of the century; hence climate change will most likely leave further imprints on species and ecosystems. This PhD thesis aims......-thirds of the areas harboring the richest amphibian faunas may be heavily impacted by at least one of the major threats by 2080. The stability of the climatic niche influences the need for a species to track climate change via dispersal, or its potential to adapt to novel climatic conditions. I therefore explore...... the phylogenetic signal in climatic niches of the world's amphibians, which serves as a surrogate quantification of niche stability. Results indicate an overall tendency of phylogenetic signal to be present in realised climatic niches, but signal strength varies across biogeographical regions and among amphibian...

  3. Estimating species occurrence, abundance, and detection probability using zero-inflated distributions.

    Science.gov (United States)

    Wenger, Seth J; Freeman, Mary C

    2008-10-01

    Researchers have developed methods to account for imperfect detection of species with either occupancy (presence absence) or count data using replicated sampling. We show how these approaches can be combined to simultaneously estimate occurrence, abundance, and detection probability by specifying a zero-inflated distribution for abundance. This approach may be particularly appropriate when patterns of occurrence and abundance arise from distinct processes operating at differing spatial or temporal scales. We apply the model to two data sets: (1) previously published data for a species of duck, Anas platyrhynchos, and (2) data for a stream fish species, Etheostoma scotti. We show that in these cases, an incomplete-detection zero-inflated modeling approach yields a superior fit to the data than other models. We propose that zero-inflated abundance models accounting for incomplete detection be considered when replicate count data are available.

  4. [National Trends in the Distribution of Candida Species Causing Candidemia in Japan from 2003 to 2014].

    Science.gov (United States)

    Kakeya, Hiroshi; Yamada, Koichi; Kaneko, Yukihiro; Yanagihara, Katsunori; Tateda, Kazuhiro; Maesaki, Shigefumi; Takesue, Yoshio; Tomono, Kazunori; Kadota, Jun-Ichi; Kaku, Mitsuo; Miyazaki, Yoshitsugu; Kamei, Katsuhiko; Shibuya, Kazutoshi; Niki, Yoshitiho; Yoshida, Minoru; Sei, Yoshihiro

    2018-01-01

    The Epidemiological Investigation Committee for Human Mycoses in Japan performed a retrospective epidemiological survey of candidemia and causative Candida species. Data from 2003 to 2014 were collected from 10 Japanese university hospitals. A total of 328,318 blood cultures were included. The prevalence of fungi in all cultures and in positive cultures were 0.58±0.09% and 4.46±0.66%, respectively. Among the results that were positive for Candida species (N=1,921), Candida albicans was the most common species (39.5%) and was followed by Candida parapsilosis (23.3%), Candida glabrata (13.2%), Candida tropicalis (7.1%), Candida krusei (3.2%), and others (13.7%). During the last 6 years, the frequency of C. albicans has significantly decreased in Japan, while that of C. glabrata has increased. Additional surveys are needed to continuously monitor the trends in the distribution of candidemia.

  5. Distribution of Po-210 in two species of predatory marine fish from the Brazilian coast

    International Nuclear Information System (INIS)

    Mársico, E.T.; Ferreira, M.S.; São Clemente, S.C.; Gouvea, R.C.S.; Jesus, E.F.O.; Conti, C.C.; Conte Junior, C.A.; Kelecom, A.G.A.C.

    2014-01-01

    Polonium-210 ( 210 Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher 210 Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg −1 for G. brasiliensis and it was 6 mBq kg −1 for C. microlepidotus. The activity concentrations varied significantly between the species and among organs. -- Highlights: • We analyzed the distribution of 210 Po in two species of predator marine fish. • 210 Po tends to accumulate in some organs, which make this radionuclide radiotoxic. • The consumption of small quantities of fish can represent high potential of 210 Po exposure. • Data about 210 Po bioaccumulation in tropical predator marine fish are limited

  6. Zinc species distribution in EDTA-extract residues of zinc-contaminated soil

    International Nuclear Information System (INIS)

    Chang, S.-H.; Wei, Y.-L.; Wang, H. Paul

    2007-01-01

    Soil sample from a site heavily contaminated with >10 wt.% zinc is sampled and extracted with aqueous solutions of ethylene diamine tetra-acetic acid (EDTA) that is a reagent frequently used to extract heavy metals in soil remediation. Three liquid/soil ratios (5/1, 20/1, and 100/1) were used in the extracting experiment. The molecular environment of the residual Zn in the EDTA-extract residues of zinc-contaminated soil is investigated with XANES technique. The results indicate that EDTA does not show considerable preference of chelating for any particular Zn species during the extraction. Zn species distribution in the sampled soil is found to resemble that in all EDTA-extract residues; Zn(OH) 2 is determined as the major zinc species (60-70%), seconded by organic zinc (21-26%) and zinc oxide (9-14%)

  7. Halocin C8: an antimicrobial peptide distributed among four halophilic archaeal genera: Natrinema, Haloterrigena, Haloferax, and Halobacterium.

    Science.gov (United States)

    Besse, Alison; Vandervennet, Manon; Goulard, Christophe; Peduzzi, Jean; Isaac, Stéphanie; Rebuffat, Sylvie; Carré-Mlouka, Alyssa

    2017-05-01

    Halophilic archaea thrive in hypersaline ecosystems and produce antimicrobial peptides (AMPs) named halocins. AMPs are essential effectors of microbial interactions in natural ecosystems. Halocin C8 is a 7.4 kDa peptide produced by Natrinema sp. AS7092. Surrounded by genes involved in regulation and transport, the halC8 gene encodes a precursor, processed into the mature halocin and an immunity protein, protecting the producing strain against its halocin. This feature constitutes a unique property of halocin C8, as known AMPs and their immunity proteins are generally encoded on distinct ORFs in an operon. By complementary in silico and PCR-based approaches, the presence of halC8 in halophilic archaea collected from various parts of the world was evidenced. The full-length halC8 gene is restricted and consistently found in the genomes of strains belonging to the phylogenetically related genera Natrinema and Haloterrigena, along with transport and regulation genes. Functional expression of halC8 was demonstrated by RT-PCR and antimicrobial assays. Active halocin C8 was shown to contain five disulphide bridges, presumably conferring a compact structure resistant to harsh environmental conditions. In other archaeal genera, Haloferax and Halobacterium, genes encoding halocin C8 with diverging immunity protein moiety were evidenced. A phylogenetic analysis of halocin C8 sequences was conducted.

  8. Distribution and antimicrobial susceptibility profile of extended-spectrum β-lactamase-producing Proteus mirabilis strains recently isolated in Japan.

    Science.gov (United States)

    Kanayama, Akiko; Kobayashi, Intetsu; Shibuya, Kazutoshi

    2015-02-01

    Here we report on the prevalence of extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis from a nationwide antimicrobial resistance survey in different geographical regions of Japan. A total of 799 P. mirabilis isolates recovered between July 2009 and June 2010 from 314 healthcare facilities were characterised according to ESBL production, source, location and antimicrobial susceptibility pattern. ESBL production was found in 364 (45.6%) of the isolates, among which 354 (97.3%) produced CTX-M-2 group β-lactamases. Of the 349 ESBL-producing isolates in which the inpatient or outpatient status of the source was known, 324 (92.8%) were from inpatients and 25 (7.2%) were from outpatients (Pmirabilis compared with 159/405 (39.3%), 119/209 (56.9%), 42/77 (54.5%) and 20/49 (40.8%), respectively, for isolates from urine, sputum, decubitus ulcer and wound specimens. Among the ESBL-producers, non-susceptibility to ciprofloxacin was found in 74.2% of the ESBL-producing isolates compared with 17.7% of the ESBL-non-producing isolates. These results show that approximately one-half of the P. mirabilis isolates from clinical specimens in Japan are ESBL-producers and that the potential for concomitant fluoroquinolone resistance must also be considered. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  9. Climate change versus deforestation: Implications for tree species distribution in the dry forests of southern Ecuador

    Science.gov (United States)

    Hildebrandt, Patrick; Cueva, Jorge; Espinosa, Carlos Iván; Stimm, Bernd; Günter, Sven

    2017-01-01

    Seasonally dry forests in the neotropics are heavily threatened by a combination of human disturbances and climate change; however, the severity of these threats is seldom contrasted. This study aims to quantify and compare the effects of deforestation and climate change on the natural spatial ranges of 17 characteristic tree species of southern Ecuador dry deciduous forests, which are heavily fragmented and support high levels of endemism as part of the Tumbesian ecoregion. We used 660 plant records to generate species distribution models and land-cover data to project species ranges for two time frames: a simulated deforestation scenario from 2008 to 2014 with native forest to anthropogenic land-use conversion, and an extreme climate change scenario (CCSM4.0, RCP 8.5) for 2050, which assumed zero change from human activities. To assess both potential threats, we compared the estimated annual rates of species loss (i.e., range shifts) affecting each species. Deforestation loss for all species averaged approximately 71 km2/year, while potential climate-attributed loss was almost 21 km2/year. Moreover, annual area loss rates due to deforestation were significantly higher than those attributed to climate-change (P < 0.01). However, projections into the future scenario show evidence of diverging displacement patterns, indicating the potential formation of novel ecosystems, which is consistent with other species assemblage predictions as result of climate change. Furthermore, we provide recommendations for management and conservation, prioritizing the most threatened species such as Albizia multiflora, Ceiba trichistandra, and Cochlospermum vitifolium. PMID:29267357

  10. Climate change versus deforestation: Implications for tree species distribution in the dry forests of southern Ecuador.

    Science.gov (United States)

    Manchego, Carlos E; Hildebrandt, Patrick; Cueva, Jorge; Espinosa, Carlos Iván; Stimm, Bernd; Günter, Sven

    2017-01-01

    Seasonally dry forests in the neotropics are heavily threatened by a combination of human disturbances and climate change; however, the severity of these threats is seldom contrasted. This study aims to quantify and compare the effects of deforestation and climate change on the natural spatial ranges of 17 characteristic tree species of southern Ecuador dry deciduous forests, which are heavily fragmented and support high levels of endemism as part of the Tumbesian ecoregion. We used 660 plant records to generate species distribution models and land-cover data to project species ranges for two time frames: a simulated deforestation scenario from 2008 to 2014 with native forest to anthropogenic land-use conversion, and an extreme climate change scenario (CCSM4.0, RCP 8.5) for 2050, which assumed zero change from human activities. To assess both potential threats, we compared the estimated annual rates of species loss (i.e., range shifts) affecting each species. Deforestation loss for all species averaged approximately 71 km2/year, while potential climate-attributed loss was almost 21 km2/year. Moreover, annual area loss rates due to deforestation were significantly higher than those attributed to climate-change (P < 0.01). However, projections into the future scenario show evidence of diverging displacement patterns, indicating the potential formation of novel ecosystems, which is consistent with other species assemblage predictions as result of climate change. Furthermore, we provide recommendations for management and conservation, prioritizing the most threatened species such as Albizia multiflora, Ceiba trichistandra, and Cochlospermum vitifolium.

  11. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    Antimicrobial resistance is a global public health challenge, which has accelerated by the overuse of antibiotics worldwide. Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics......-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...

  12. Incorporating plant fossil data into species distribution models is not straightforward: Pitfalls and possible solutions

    Science.gov (United States)

    Moreno-Amat, Elena; Rubiales, Juan Manuel; Morales-Molino, César; García-Amorena, Ignacio

    2017-08-01

    The increasing development of species distribution models (SDMs) using palaeodata has created new prospects to address questions of evolution, ecology and biogeography from wider perspectives. Palaeobotanical data provide information on the past distribution of taxa at a given time and place and its incorporation on modelling has contributed to advancing the SDM field. This has allowed, for example, to calibrate models under past climate conditions or to validate projected models calibrated on current species distributions. However, these data also bear certain shortcomings when used in SDMs that may hinder the resulting ecological outcomes and eventually lead to misleading conclusions. Palaeodata may not be equivalent to present data, but instead frequently exhibit limitations and biases regarding species representation, taxonomy and chronological control, and their inclusion in SDMs should be carefully assessed. The limitations of palaeobotanical data applied to SDM studies are infrequently discussed and often neglected in the modelling literature; thus, we argue for the more careful selection and control of these data. We encourage authors to use palaeobotanical data in their SDMs studies and for doing so, we propose some recommendations to improve the robustness, reliability and significance of palaeo-SDM analyses.

  13. No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

    Science.gov (United States)

    Turner, Benjamin L; Zalamea, Paul-Camilo; Condit, Richard; Winter, Klaus; Wright, S Joseph; Dalling, James W

    2017-04-01

    It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama. Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability. Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency. We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics. No claim to original US government works New Phytologist © 2016 New Phytologist Trust.

  14. Coagulase-negative Staphylococci in Danish blood cultures: species distribution and antibiotic susceptibility.

    Science.gov (United States)

    Jarløv, J O; Højbjerg, T; Busch-Sørensen, C; Scheibel, J; Møller, J K; Kolmos, H J; Wandall, D A

    1996-03-01

    The distribution and antibiotic susceptibility of coagulase-negative staphylococci (CoNS) isolated from blood cultures was examined in samples from hospitals covering most of Denmark. A total of 499 CoNS isolates were detected in 477 blood cultures from 340 patients and speciated as Staphylococcus epidermidis, 285; Staphylococcus hominis, 61; Staphylococcus haemolyticus, 43; Staphylococcus warneri, 12; Staphylococcus cohnii, 7; Staphylococcus saprophyticus, 4; Staphylococcus capitis, 2 and Staphylococcus lugdunensis, 1. Seventy-eight isolates could not be identified to species level and six were Micrococcus spp. In 108 (22.6%) blood culture sets, more than one CoNS strain were found, as detected by species identification, antibiogram and biotyping. Significantly more blood cultures from patients in university hospitals were drawn from central venous catheters. Comparing university and non-university hospitals, the overall antibiotic susceptibility among CoNS was only slightly different, except for methicillin and amikacin. The prevalence of methicillin-resistant strains was 35.1% in the university hospital strains vs. 25.3% in the non-university hospital strains. The overall prevalence of methicillin resistance was 32%. Great geographic variation in both species distribution and antibiotic resistance was observed. The high prevalence of S. epidermidis makes subtyping of this species important.

  15. Drought responses of three closely related Caragana species: implication for their vicarious distribution.

    Science.gov (United States)

    Ma, Fei; Na, Xiaofan; Xu, Tingting

    2016-05-01

    Drought is a major environmental constraint affecting growth and distribution of plants in the desert region of the Inner Mongolia plateau. Caragana microphylla, C. liouana, and C. korshinskii are phylogenetically close but distribute vicariously in Mongolia plateau. To gain a better understanding of the ecological differentiation between these three species, we examined the leaf gas exchange, growth, water use efficiency, biomass accumulation and allocation by subjecting their seedlings to low and high drought treatments in a glasshouse. Increasing drought stress had a significant effect on many aspects of seedling performance in all species, but the physiology and growth varied with species in response to drought. C. korshinskii exhibited lower sensitivity of photosynthetic rate and growth, lower specific leaf area, higher biomass allocation to roots, higher levels of water use efficiency to drought compared with the other two species. Only minor interspecific differences in growth performances were observed between C. liouana and C. microphylla. These results indicated that faster seedling growth rate and more efficient water use of C. korshinskii should confer increased drought tolerance and facilitate its establishment in more severe drought regions relative to C. liouana and C. microphylla.

  16. Proximal Soil Sensing - A Contribution for Species Habitat Distribution Modelling of Earthworms in Agricultural Soils?

    Science.gov (United States)

    Schirrmann, Michael; Joschko, Monika; Gebbers, Robin; Kramer, Eckart; Zörner, Mirjam; Barkusky, Dietmar; Timmer, Jens

    2016-01-01

    Earthworms are important for maintaining soil ecosystem functioning and serve as indicators of soil fertility. However, detection of earthworms is time-consuming, which hinders the assessment of earthworm abundances with high sampling density over entire fields. Recent developments of mobile terrestrial sensor platforms for proximal soil sensing (PSS) provided new tools for collecting dense spatial information of soils using various sensing principles. Yet, the potential of PSS for assessing earthworm habitats is largely unexplored. This study investigates whether PSS data contribute to the spatial prediction of earthworm abundances in species distribution models of agricultural soils. Proximal soil sensing data, e.g., soil electrical conductivity (EC), pH, and near infrared absorbance (NIR), were collected in real-time in a field with two management strategies (reduced tillage / conventional tillage) and sandy to loam soils. PSS was related to observations from a long-term (11 years) earthworm observation study conducted at 42 plots. Earthworms were sampled from 0.5 x 0.5 x 0.2 m³ soil blocks and identified to species level. Sensor data were highly correlated with earthworm abundances observed in reduced tillage but less correlated with earthworm abundances observed in conventional tillage. This may indicate that management influences the sensor-earthworm relationship. Generalized additive models and state-space models showed that modelling based on data fusion from EC, pH, and NIR sensors produced better results than modelling without sensor data or data from just a single sensor. Regarding the individual earthworm species, particular sensor combinations were more appropriate than others due to the different habitat requirements of the earthworms. Earthworm species with soil-specific habitat preferences were spatially predicted with higher accuracy by PSS than more ubiquitous species. Our findings suggest that PSS contributes to the spatial modelling of

  17. Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese.

    Science.gov (United States)

    Fernando, Denise R; Marshall, Alan T; Lynch, Jonathan P

    2016-01-01

    Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn) toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn) when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg), sulphur (S) and calcium (Ca) distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress.

  18. Plant species distribution in relation to water-table depth and soil redox potential in montane riparian meadows

    Science.gov (United States)

    Kathleen A. Dwire; J. Boone Kauffman; John E. Baham

    2006-01-01

    The distribution of riparian plant species is largely driven by hydrologic and soil variables, and riparian plant communities frequently occur in relatively distinct zones along streamside elevational and soil textural gradients. In two montane meadows in northeast Oregon, USA, we examined plant species distribution in three riparian plant communities¡ªdefined as wet,...

  19. Fit-for-purpose: species distribution model performance depends on evaluation criteria -Dutch hoverflies as a case study

    NARCIS (Netherlands)

    Aguirre-Gutiérrez, J.; Carvalheiro, L.G.; Polce, C.; van Loon, E.E.; Raes, N.; Reemer, M.; Biesmeijer, J.C.

    2013-01-01

    Understanding species distributions and the factors limiting them is an important topic in ecology and conservation, including in nature reserve selection and predicting climate change impacts. While Species Distribution Models (SDM) are the main tool used for these purposes, choosing the best SDM

  20. Are species photosynthetic characteristics good predictors of seedling post-hurricane demographic patterns and species spatiotemporal distribution in a hurricane impacted wet montane forest?

    Science.gov (United States)

    Luke, Denneko; McLaren, Kurt

    2018-05-01

    In situ measurements of leaf level photosynthetic response to light were collected from seedlings of ten tree species from a tropical montane wet forest, the John Crow Mountains, Jamaica. A model-based recursive partitioning ('mob') algorithm was then used to identify species associations based on their fitted photosynthetic response curves. Leaf area dark respiration (RD) and light saturated maximum photosynthetic (Amax) rates were also used as 'mob' partitioning variables, to identify species associations based on seedling demographic patterns (from June 2007 to May 2010) following a hurricane (Aug. 2007) and the spatiotemporal distribution patterns of stems in 2006 and 2012. RD and Amax rates ranged from 1.14 to 2.02 μmol (CO2) m-2s-1 and 2.97-5.87 μmol (CO2) m-2s-1, respectively, placing the ten species in the range of intermediate shade tolerance. Several parsimonious species 'mob' groups were formed based on 1) interspecific differences among species response curves, 2) variations in post-hurricane seedling demographic trends and 3) RD rates and species spatiotemporal distribution patterns at aspects that are more or less exposed to hurricanes. The composition of parsimonious groupings based on photosynthetic curves was not concordant with the groups based on demographic trends but was partially concordant with the RD - species spatiotemporal distribution groups. Our results indicated that the influence of photosynthetic characteristics on demographic traits and species distributions was not straightforward. Rather, there was a complex pattern of interaction between ecophysiological and demographic traits, which determined species successional status, post-hurricane response and ultimately, species distribution at our study site.

  1. Predicting habitat suitability for rare plants at local spatial scales using a species distribution model.

    Science.gov (United States)

    Gogol-Prokurat, Melanie

    2011-01-01

    If species distribution models (SDMs) can rank habitat suitability at a local scale, they may be a valuable conservation planning tool for rare, patchily distributed species. This study assessed the ability of Maxent, an SDM reported to be appropriate for modeling rare species, to rank habitat suitability at a local scale for four edaphic endemic rare plants of gabbroic soils in El Dorado County, California, and examined the effects of grain size, spatial extent, and fine-grain environmental predictors on local-scale model accuracy. Models were developed using species occurrence data mapped on public lands and were evaluated using an independent data set of presence and absence locations on surrounding lands, mimicking a typical conservation-planning scenario that prioritizes potential habitat on unsurveyed lands surrounding known occurrences. Maxent produced models that were successful at discriminating between suitable and unsuitable habitat at the local scale for all four species, and predicted habitat suitability values were proportional to likelihood of occurrence or population abundance for three of four species. Unfortunately, models with the best discrimination (i.e., AUC) were not always the most useful for ranking habitat suitability. The use of independent test data showed metrics that were valuable for evaluating which variables and model choices (e.g., grain, extent) to use in guiding habitat prioritization for conservation of these species. A goodness-of-fit test was used to determine whether habitat suitability values ranked habitat suitability on a continuous scale. If they did not, a minimum acceptable error predicted area criterion was used to determine the threshold for classifying habitat as suitable or unsuitable. I found a trade-off between model extent and the use of fine-grain environmental variables: goodness of fit was improved at larger extents, and fine-grain environmental variables improved local-scale accuracy, but fine-grain variables

  2. Ecological relationships of meso-scale distribution in 25 neotropical vertebrate species.

    Science.gov (United States)

    Michalski, Lincoln José; Norris, Darren; de Oliveira, Tadeu Gomes; Michalski, Fernanda

    2015-01-01

    Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos). Generalized linear models (GLMs) were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river) on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca) and Puma (Puma concolor)] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons). Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy) all of which were photographed more (3 to 10 fold increase) during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%). Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major) and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy) were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all species

  3. Ecological relationships of meso-scale distribution in 25 neotropical vertebrate species.

    Directory of Open Access Journals (Sweden)

    Lincoln José Michalski

    Full Text Available Vertebrates are a vital ecological component of Amazon forest biodiversity. Although vertebrates are a functionally important part of various ecosystem services they continue to be threatened by anthropogenic impacts throughout the Amazon. Here we use a standardized, regularly spaced arrangement of camera traps within 25km2 to provide a baseline assessment of vertebrate species diversity in a sustainable use protected area in the eastern Brazilian Amazon. We examined seasonal differences in the per species encounter rates (number of photos per camera trap and number of cameras with photos. Generalized linear models (GLMs were then used to examine the influence of five variables (altitude, canopy cover, basal area, distance to nearest river and distance to nearest large river on the number of photos per species and on functional groups. GLMs were also used to examine the relationships between large predators [Jaguar (Panthera onca and Puma (Puma concolor] and their prey. A total of 649 independent photos of 25 species were obtained from 1,800 camera trap days (900 each during wet and dry seasons. Only ungulates and rodents showed significant seasonal differences in the number of photos per camera. The number of photos differed between seasons for only three species (Mazama americana, Dasyprocta leporina and Myoprocta acouchy all of which were photographed more (3 to 10 fold increase during the wet season. Mazama americana was the only species where a significant difference was found in occupancy, with more photos in more cameras during the wet season. For most groups and species variation in the number of photos per camera was only explained weakly by the GLMs (deviance explained ranging from 10.3 to 54.4%. Terrestrial birds (Crax alector, Psophia crepitans and Tinamus major and rodents (Cuniculus paca, Dasyprocta leporina and M. acouchy were the notable exceptions, with our GLMs significantly explaining variation in the distribution of all

  4. The roles of competition and habitat in the dynamics of populations and species distributions.

    Science.gov (United States)

    Yackulic, Charles B; Reid, Janice; Nichols, James D; Hines, James E; Davis, Raymond; Forsman, Eric

    2014-02-01

    The role of competition in structuring biotic communities at fine spatial scales is well known from detailed process-based studies. Our understanding of competition's importance at broader scales is less resolved and mainly based on static species distribution maps. Here, we bridge this gap by examining the joint occupancy dynamics of an invading species (Barred Owl, Strix varia) and a resident species (Northern Spotted Owl, Strix occidentalis caurina) in a 1000-km study area over a 22-year period. Past studies of these competitors have focused on the dynamics of one species at a time, hindering efforts to parse out the roles of habitat and competition and to forecast the future of the resident species. In addition, while these studies accounted for the imperfect detection of the focal species, no multi-season analysis of these species has accounted for the imperfect detection of the secondary species, potentially biasing inference. We analyzed survey data using models that combine the general multistate-multi-season occupancy modeling framework with autologistic modeling, allowing us to account for important aspects of our study system. We found that local extinction probability increases for each species when the other is present; however, the effect of the invader on the resident is greater. Although the species prefer different habitats, these habitats are highly correlated at the patch scale, and the impacts of invader on the resident are greatest in patches that would otherwise be optimal. As a consequence, competition leads to a weaker relationship between habitat and Northern Spotted Owl occupancy. Colonization and extinction rates of the invader are closely related to neighborhood occupancy, and over the first half of the study the availability of colonists limited the rate of population growth. Competition is likely to exclude the resident species, both through its immediate effects on local extinction and by indirectly lowering colonization rates as

  5. Biodiversity and the Lotka-Volterra theory of species interactions: open systems and the distribution of logarithmic densities.

    Science.gov (United States)

    Wilson, William G; Lundberg, Per

    2004-09-22

    Theoretical interest in the distributions of species abundances observed in ecological communities has focused recently on the results of models that assume all species are identical in their interactions with one another, and rely upon immigration and speciation to promote coexistence. Here we examine a one-trophic level system with generalized species interactions, including species-specific intraspecific and interspecific interaction strengths, and density-independent immigration from a regional species pool. Comparisons between results from numerical integrations and an approximate analytic calculation for random communities demonstrate good agreement, and both approaches yield abundance distributions of nearly arbitrary shape, including bimodality for intermediate immigration rates.

  6. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... of Animation of Antimicrobial Resistance More in Antimicrobial ... Antimicrobial Resistance Monitoring System About NARMS 2015 NARMS Integrated ...

  7. Distribution and abundance of diatom species from coastal waters of Karachi, Pakistan

    International Nuclear Information System (INIS)

    Khokhar, F. N.; Burhan, Z.; Iqbal, P.; Abbasi, J.; Siddiqui, P.

    2016-01-01

    This is the first comprehensive study on the distribution and abundance of diatom species from the coastal and nearshore waters of Karachi, Pakistan, bordering northern Arabian Sea. A total of 20 genera are recorded in high abundance (Cerataulina, Chaetoceros, Coscinodiscus, Cylindrotheca, Eucampia, Guinardia, Haslea, Hemiaulus, Lauderia, Lennoxia, Leptocylindrus, Navicula, Nitzschia, Trieres, Planktoniella, Pleurosigma, Pseudo-nitzschia, Rhizosolenia, Thalassionema and Thalassiosira). The most abundant genera were observed Guinardia, Chaetoceros, Leptocylindrus, Nitzschia and Lennoxia at all stations. Manora coastal station (MI-1) had high abundance corresponding with high Chlorophyll a (130 meu gL- l) values. Minimum abundance and low chlorophyll a value (0.05μgL-l) were observed at Mubarak Village coastal station (MV-1). Diatom abundance showed significant correlation with Chlorophyll a. In present study 12 centric and 8 pennate forms were recorded and similarly high diversity of centric taxa was observed compared to pennate forms. A total of 134 species are recorded of which 40 species were observed at four stations, 31species at three stations, 23 at two stations and 40 species only at one station. The total phytoplankton and diatom peak abundance was observed during NE monsoon (winter season) associated with nutrient loading through up-sloping of nutrient rich water upwelled off of Oman during South West monsoon. Overall higher diversity was observed at Manora coastal and nearshore stations (MI-1, MI-2) indicating the influence of organic pollution loading from Layari and Malir rivers. (author)

  8. The influence of electrohydrodynamic flow on the distribution of chemical species in positive corona

    Science.gov (United States)

    Pontiga, Francisco; Yanallah, Khelifa; Bouazza, R.; Chen, Junhong

    2015-09-01

    A numerical simulation of positive corona discharge in air, including the effect of electrohydrodynamic (EHD) motion of the gas, has been carried out. Air flow is assumed to be confined between two parallel plates, and corona discharge is produced around a thin wire, midway between the plates. Therefore, fluid dynamics equations, including electrical forces, have been solved together with the continuity equation of each neutral species. The plasma chemical model included 24 chemical reactions and ten neutral species, in addition to electrons and positive ions. The results of the simulation have shown that the influence of EHD flow on the spatial distributions of the species is quite different depending on the species. Hence, reactive species like atomic oxygen and atomic nitrogen are confined to the vicinity of the wire, and they are weakly affected by the EHD gas motion. In contrast, nitrogen oxides and ozone are efficiently dragged outside the active region of the corona discharge by the EHD flow. This work was supported by the Spanish Government Agency ``Ministerio de Ciencia e Innovación'' under Contract No. FIS2011-25161.

  9. Species richness and distribution of bryophytes within different phytophysiognomies in the Chapada Diamantina region of Brazil

    Directory of Open Access Journals (Sweden)

    Emilia de Brito Valente

    2013-06-01

    Full Text Available The Chapada Diamantina ecoregion is within the caatinga (shrublands biome of Brazil. Environmental factors determine the phytophysiognomies that distinguish the ecoregion from the surrounding areas. This study aimed to investigate the distribution of bryophyte flora in this ecoregion, by phytophysiognomy and elevational zone. Analyzing specimens we collected from five municipalities in the region, together with specimens (previously collected from the region in herbaria, we identified 400 taxa. The phytophysiognomies that presented the highest species richness and the greatest numbers of exclusive taxa were forests and campos rupestres (dry, rocky grasslands, which respectively accounted for 51% and 40% of the taxa, compared with only 5% and 4%, respectively, for the caatinga and cerrado (savanna. Species richness and the numbers of exclusive taxa were highest in the lower and upper montane zones. There was a predominance of neotropical taxa and a significant number of disjunct species found in Brazil and in the Andes region. We conclude that the Chapada Diamantina region is an important center of bryophyte diversity, harboring not only a great number of species overall but also a considerable number of species exclusive to the region, primarily in forests and campos rupestres at elevations above 800 m.

  10. Species distribution modeling for the invasive raccoon dog (Nyctereutes procyonoides) in Austria and first range predictions for alpine environments

    OpenAIRE

    Duscher Tanja; Nopp-Mayr Ursula

    2017-01-01

    Species distribution models are important tools for wildlife management planning, particularly in the case of invasive species. We employed a recent framework for niche-based invasive species distribution modeling to predict the probability of presence for the invasive raccoon dog (Nyctereutes procyonoides) in Austria. The raccoon dog is an adaptive, mobile and highly reproductive Asiatic canid that has successfully invaded many parts of Europe. It is known...

  11. Fit-for-purpose: species distribution model performance depends on evaluation criteria - Dutch Hoverflies as a case study.

    Science.gov (United States)

    Aguirre-Gutiérrez, Jesús; Carvalheiro, Luísa G; Polce, Chiara; van Loon, E Emiel; Raes, Niels; Reemer, Menno; Biesmeijer, Jacobus C

    2013-01-01

    Understanding species distributions and the factors limiting them is an important topic in ecology and conservation, including in nature reserve selection and predicting climate change impacts. While Species Distribution Models (SDM) are the main tool used for these purposes, choosing the best SDM algorithm is not straightforward as these are plentiful and can be applied in many different ways. SDM are used mainly to gain insight in 1) overall species distributions, 2) their past-present-future probability of occurrence and/or 3) to understand their ecological niche limits (also referred to as ecological niche modelling). The fact that these three aims may require different models and outputs is, however, rarely considered and has not been evaluated consistently. Here we use data from a systematically sampled set of species occurrences to specifically test the performance of Species Distribution Models across several commonly used algorithms. Species range in distribution patterns from rare to common and from local to widespread. We compare overall model fit (representing species distribution), the accuracy of the predictions at multiple spatial scales, and the consistency in selection of environmental correlations all across multiple modelling runs. As expected, the choice of modelling algorithm determines model outcome. However, model quality depends not only on the algorithm, but also on the measure of model fit used and the scale at which it is used. Although model fit was higher for the consensus approach and Maxent, Maxent and GAM models were more consistent in estimating local occurrence, while RF and GBM showed higher consistency in environmental variables selection. Model outcomes diverged more for narrowly distributed species than for widespread species. We suggest that matching study aims with modelling approach is essential in Species Distribution Models, and provide suggestions how to do this for different modelling aims and species' data

  12. Modeling species distributions from heterogeneous data for the biogeographic regionalization of the European bryophyte flora.

    Directory of Open Access Journals (Sweden)

    Rubén G Mateo

    Full Text Available The definition of biogeographic regions provides a fundamental framework for a range of basic and applied questions in biogeography, evolutionary biology, systematics and conservation. Previous research suggested that environmental forcing results in highly congruent regionalization patterns across taxa, but that the size and number of regions depends on the dispersal ability of the taxa considered. We produced a biogeographic regionalization of European bryophytes and hypothesized that (1 regions defined for bryophytes would differ from those defined for other taxa due to the highly specific eco-physiology of the group and (2 their high dispersal ability would result in the resolution of few, large regions. Species distributions were recorded using 10,000 km2 MGRS pixels. Because of the lack of data across large portions of the area, species distribution models employing macroclimatic variables as predictors were used to determine the potential composition of empty pixels. K-means clustering analyses of the pixels based on their potential species composition were employed to define biogeographic regions. The optimal number of regions was determined by v-fold cross-validation and Moran's I statistic. The spatial congruence of the regions identified from their potential bryophyte assemblages with large-scale vegetation patterns is at odds with our primary hypothesis. This reinforces the notion that post-glacial migration patterns might have been much more similar in bryophytes and vascular plants than previously thought. The substantially lower optimal number of clusters and the absence of nested patterns within the main biogeographic regions, as compared to identical analyses in vascular plants, support our second hypothesis. The modelling approach implemented here is, however, based on many assumptions that are discussed but can only be tested when additional data on species distributions become available, highlighting the substantial

  13. Implications of human induced changes on the distribution of important plant species in the northwestern coastal desert of Egypt

    Directory of Open Access Journals (Sweden)

    Marwa Waseem Halmy

    2015-12-01

    Full Text Available The application of species distribution modeling in deserts is a useful tool for mapping species and assessing the impact of human induced changes on individual species. Such applications are still rare, and this may be attributed to the fact that much of the arid lands and deserts around the world are located in inaccessible areas. Few studies have conducted spatially explicit modeling of plant species distribution in Egypt. The random forest modeling approach was applied to climatic and land-surface parameters to predict the distribution of ten important plant species in an arid landscape in the northwestern coastal desert of Egypt. The impact of changes in land use and climate on the distribution of the plant species was assessed. The results indicate that the changes in land use in the area have resulted in habitat loss for all the modeled species. Projected future changes in land use reveals that all the modeled species will continue to suffer habitat loss. The projected impact of modeled climate scenarios (A1B, A2A and B2A on the distribution of the modeled species by 2040 varied. Some of the species were projected to be adversely affected by the changes in climate, while other species are expected to benefit from these changes. The combined impact of the changes in land use and climate pose serious threats to most of the modeled species. The study found that all the species are expected to suffer loss in habitat,