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Test Species (test + species)
Selected AbstractsComparative study on sensitivity of higher plants and fish to heavy fuel oilENVIRONMENTAL TOXICOLOGY, Issue 4 2004N. Kazlauskien Abstract Laboratory tests were conducted on higher plants [garden cress (Lepidium sativum), great duckweed (Spirodela polyrrhiza), and Tradescantia clone BNL 02] and fish [rainbow trout (Oncorhynchus mykiss) at all stages of development: eggs, larvae and adults] to estimate their sensitivity to heavy fuel oil (HFO). A number of biological indices (survival, growth, and physiological and morphological parameters) as well as the genotoxic impact (Tradescantia) of HFO was evaluated by acute and chronic toxicity tests. Fish were found to be more sensitive to the toxic effect of HFO than were higher plants. EC50 values obtained for higher plants ranged from 8.7 g/L (L. sativum) to 19.8 g/L (Tradescantia), and maximum-acceptable-toxicant concentration (MATC) values ranged from 0.1 to 1.0 g/L of total HFO for L. sativum and Tradescantia, respectively. The 96-h LC50 values ranged from 0.33 g/L, for larvae, to 2.97 g/L, for adult fish, and the MATC value for fish was found to be equal to 0.0042 g/L of total HFO. To evaluate and predict the ecological risk of the overall effects of oil spills, studies should be performed using a set of acute and chronic bioassays that include test species of different phylogenetic levels with the most sensitive morphological, physiological, and genotoxic indices. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 449,451, 2004 [source] Quick assessment of cytotoxins effect on Daphnia magna using in vivo fluorescence microscopyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2010Vera V. Teplova Abstract A novel approach to contaminant toxicity screening is proposed. The use of fluorescent microscopy with fluorescent dyes allows for assessing intoxication of Daphnia magna tissues, at various stages of exposure, to contaminants present in water. As shown, D. magna may not only be used as a test species in toxicity tests based on its lethality, but due to its translucency and application of fluorescent probes, separate steps of its intoxication and dying can be visualized. Using a variety of fluorescent probes, the present study also contributes to a better understanding of the toxicity mechanisms. Environ. Toxicol. Chem. 2010;29:1345,1348. © 2010 SETAC [source] Toxicity of methyl tert butyl ether to soil invertebrates (springtails: Folsomia candida, Proisotoma minuta, and Onychiurus folsomi) and lettuce (Lactuca sativa)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2010Matthew Dodd Abstract Experiments were conducted to assess the toxicity of methyl tert butyl ether (MTBE) to three species of Collembola (Proisotoma minuta, Folsomia candida, and Onychiurus folsomi) and lettuce (Lactuca sativa L.) using an artificial Organization for Economic Cooperation and Development (OECD) soil and field-collected sandy loam and silt loam soil samples. Soil invertebrate tests were carried out in airtight vials to prevent volatilization of MTBE out of the test units and to allow for direct head-space sampling and gas chromatography-mass spectrometry (GC-MS) analysis for residual MTBE. The use of the airtight vial protocol proved to be very successful, in that the measured MTBE concentrations at the beginning of the experiments were within 95% of nominal concentrations. The test methods used in this study could be used to test the toxicity of other volatile organic compounds to Collembola. The soil invertebrates tested had inhibitory concentration (ICx) and lethal concentration (LCx) values that ranged from 242 to 844 mg MTBE/kg dry soil. When the three test species of Collembola were tested under identical conditions in the artificial OECD soil, O. folsomi was the most sensitive collembolan, with a median inhibitory concentration (IC50; reproduction) of 296 mg MTBE/kg dry soil. The most sensitive endpoint for lettuce was an IC50 for root length of 81 mg MTBE/kg dry soil after 5 d of germination in OECD soil. Data on the loss of MTBE from the three test soils over time indicated that MTBE was retained in the silt loam soil longer than in either the sandy loam or the artificial OECD soil. Environ. Toxicol. Chem. 2010;29:338,346. © 2009 SETAC [source] Avoidance tests in site-specific risk assessment,influence of soil properties on the avoidance response of collembola and earthworms,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2008Tiago Natal-da-Luz Abstract The ability of organisms to avoid contaminated soils can act as an indicator of toxic potential in a particular soil. Based on the escape response of earthworms and Collembola, avoidance tests with these soil organisms have great potential as early screening tools in site-specific assessment. These tests are becoming more common in soil ecotoxicology, because they are ecologically relevant and have a shorter duration time compared with standardized soil toxicity tests. The avoidance response of soil invertebrates, however, can be influenced by the soil properties (e.g., organic matter content and texture) that affect behavior of the test species in the exposure matrix. Such an influence could mask a possible effect of the contaminant. Therefore, the effects of soil properties on performance of test species in the exposure media should be considered during risk assessment of contaminated soils. Avoidance tests with earthworms (Eisenia andrei) and springtails (Folsomia candida) were performed to identify the influence of both organic matter content and texture on the avoidance response of representative soil organisms. Distinct artificial soils were prepared by modifying quantities of the standard artificial soil components described by the Organization for Economic Co-operation and Development to achieve different organic matter and texture classes. Several combinations of each factor were tested. Results showed that both properties influenced the avoidance response of organisms, which avoided soils with low organic matter content and fine texture. Springtails were less sensitive to changes in these soil constituents compared with earthworms, indicating springtails can be used for site-specific assessments of contaminated soils with a wider range of respective soil properties. [source] Development and validation of a 2,000-gene microarray for the fathead minnow (Pimephales promelas)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2007Patrick Larkin Abstract Gene microarrays provide the field of ecotoxicology new tools to identify mechanisms of action of chemicals and chemical mixtures. Herein we describe the development and application of a 2,000-gene oligonucleotide microarray for the fathead minnow Pimephales promelas, a species commonly used in ecological risk assessments in North America. The microarrays were developed from various cDNA and subtraction libraries that we constructed. Consistency and reproducibility of the microarrays were documented by examining multiple technical replicates. To test application of the fathead minnow microarrays, gene expression profiles of fish exposed to 17,-estradiol, a well-characterized estrogen receptor (ER) agonist, were examined. For these experiments, adult male fathead minnows were exposed for 24 h to waterborne 17,-estradiol (40 or 100 ng/L) in a flow-through system, and gene expression in liver samples was characterized. Seventy-one genes were identified as differentially regulated by estradiol exposure. Examination of the gene ontology designations of these genes revealed patterns consistent with estradiol's expected mechanisms of action and also provided novel insights as to molecular effects of the estrogen. Our studies indicate the feasibility and utility of microarrays as a basis for understanding biological responses to chemical exposure in a model ecotoxicology test species. [source] Uncertainty analysis of single-concentration exposure data for risk assessment,introducing the species effect distribution approachENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2006Janeck J. Scott-fordsmand Abstract In recent years, the inclusion of uncertainty analysis in risk assessment has been much debated. One pertinent issue is the translation of the effects observed with a limited number of test species to a general protection level for most or all species present in the environment. In a number of cases, toxicity data may consist of data from tests employing only a control and one treatment. Given that more species (or processes) have been tested with the same treatment, the treatment can be considered as fixed, and the effect level of the individual species (or processes) can be considered as variable. The distribution of effects can be viewed as a species effect distribution for that treatment. The distribution will represent all organisms and may be used to predict the maximum impact on any fraction of all organisms (e.g., 95% of all species). Hence, it is possible to predict the maximum effect level, with a selected certainty, for a given fraction of all species. [source] Field evaluation of an avian risk assessment modelENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006Nimish B. Vyas Abstract We conducted two laboratory subacute dietary toxicity tests and one outdoor subacute dietary toxicity test to determine the effectiveness of the U.S. Environmental Protection Agency's deterministic risk assessment model for evaluating the potential of adverse effects to birds in the field. We tested technical-grade diazinon and its D·Z·N® 50W (50% diazinon active ingredient wettable powder) formulation on Canada goose (Branta canadensis) goslings. Brain acetylcholinesterase activity was measured, and the feathers and skin, feet, and gastrointestinal contents were analyzed for diazinon residues. The dose,response curves showed that diazinon was significantly more toxic to goslings in the outdoor test than in the laboratory tests. The deterministic risk assessment method identified the potential for risk to birds in general, but the factors associated with extrapolating from the laboratory to the field, and from the laboratory test species to other species, resulted in the underestimation of risk to the goslings. The present study indicates that laboratory-based risk quotients should be interpreted with caution. [source] Application of toxicity identification evaluation procedures for characterizing produced water using the tropical mysid, Metamysidopsis insularisENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004Najila Elias-Samlalsingh Abstract Toxicity identification evaluations (TIEs) were performed on seven produced water (PW) effluents from inland discharge facilities operated in Trinidad and Tobago, a Caribbean tropical country with one of the oldest commercial oil industries in the world. The research was performed to determine the presence and magnitude of toxicity and characterize which toxicants are responsible for observed effects. Marine effluent toxicity characterizations with Metamysidopsis insularis revealed high whole acute toxic-unit response for produced water ranged from 8.1 to >17.0 acute toxic-unit (initial toxicity test) and 5.7 to 1,111 acute toxic-unit (baseline toxicity test). Toxicity test results for all sites except one, which had the highest toxicity, are comparative with similar studies on produced water. The toxicological causality of this complex mixture differed for each PW with nonpolar organics being consistently toxic in all samples. Other potential toxicants contributing to overall toxicity to a much lesser extent were metals, ammonia, and volatile organic compounds. With the use of sodium thiosulfate and filtration manipulations for only PW6 sample, there was very slight reduction in toxicity; therefore, oxidants and filterable materials were not a great contributing factor. Whole effluent toxicity also can be attributed to ionic imbalance and the very stable oil-in-water emulsion that consists of fine oil droplets (less than 0.1,10 ,m with an average diameter of 2.5 ,m). This investigation is the first of its type in Trinidad and demonstrates clearly the applicability of this test method and local test species for evaluating complex effluents in tropical environments. [source] In situ water and sediment toxicity in an agricultural watershedENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Bryn M. Phillips Abstract The Salinas River receives inputs from extensive farmlands before flowing into the Salinas River National Wildlife Refuge and the Monterey Bay National Marine Sanctuary (CA, USA). Previous monitoring using laboratory toxicity tests and chemical analyses identified toxic agricultural drain-water inputs in this system. Using caged daphnids (Ceriodaphnia dubia) and amphipods (Hyalella azteca), we investigated in situ toxicity at stations downstream from an agricultural drain relative to a reference station. A flow sensor indicated highly variable inputs from irrigation, and daily synoptic chemical analyses using enzyme-linked immunosorbent assay techniques demonstrated fluctuating concentrations of organophosphate pesticides. Test organism mortality in the field coincided with contaminant concentrations that exceeded chemical effect thresholds for the test species. Laboratory toxicity tests using C. dubia were comparable to results from field exposures, but tests with H. azteca were not. Laboratory exposures can be reasonable surrogates for field evaluations in this system, but they were less effective for assessing short-term temporal variability. Results from the field toxicity studies corroborated results of bioassessment surveys conducted as part of a concurrent study. Toxicity identification evaluations indicated that organophosphate pesticides caused toxicity to daphnids and that effects of suspended solids were negligible. [source] Sediment chemical contamination and toxicity associated with a coastal golf course complex,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2001Michael A. Lewis Abstract The increasing density of golf courses represents a potential source of sediment contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to determine the concentrations of contaminants and toxicities of sediments impacted by a coastal golf course complex. Sediment contaminant concentrations were determined at least twice during the two-year study period at 14 sampling stations. In addition, a combination of acute and chronic bioassays were conducted exposing four invertebrate test species to whole sediments and associated pore waters. Overall, the Florida, USA, golf course complex had a measurable impact on sediment chemical quality, particularly in near-field areas. Higher concentrations of several trace metals and organochlorine pesticides were detected in many golf course-associated sediments compared with reference areas; however, concentrations decreased seaward and only a few, primarily chlorinated pesticides, exceeded proposed sediment quality guidelines. Chromium, zinc, and mercury were detected more frequently than other trace metals. The DDT and associated metabolites, dieldrin and chlordane, were the more commonly detected organic contaminants. Acute toxicity was uncommon and occurred consistently for sediment collected from one coastal location. In contrast, chronic toxicity occurred at several study sites based on the response of Mysidopsis bahia. It was concluded that the impact of golf course runoff on sediment quality may be subtle and sensitive biological assessment methods, such as chronic toxicity tests, will be needed to detect adverse effects. [source] Field assessments in conjunction with whole effluent toxicity testingENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2000Thomas W. La Point Abstract Whole effluent toxicity (WET) tests are widely used to assess potential effects of wastewater discharges on aquatic life. This paper represents a summary of chapters in a 1996 Society of Environmental Toxicology and Chemistry,sponsored workshop and a literature review concerning linkages between WET testing and associated field biomonitoring. Most published studies thus far focus primarily on benthic macroinvertebrates and on effluent-dominated stream systems in which effluents demonstrate little or no significant acute toxicity. Fewer studies examine WET test predictability in other aquatic ecosystems (e.g., wetlands, estuaries, large rivers) or deal with instream biota such as fish and primary producers. Published results indicate that standards for the usual WET freshwater test species, Ceriodaphnia dubia and Pimephales promelas, may not always protect most of the species inhabiting a receiving stream. Although WET tests are useful in predicting aquatic individual responses, they are not meant to directly measure natural population or community responses. Further, they do not address bioconcentration or bioaccumulation of hydrophobic compounds; do not assess eutrophication effects in receiving systems; and lastly, do not reflect genotoxic effects or function to test for endocrine-disrupting chemicals. Consequently, a more direct evaluation of ecosystem health, using bioassessment techniques, may be needed to properly evaluate aquatic systems affected by wastewater discharges. [source] Evaluation of Bioaccumulation Using In Vivo Laboratory and Field Studies,INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2009Annie V Weisbrod Abstract A primary consideration in the evaluation of chemicals is the potential for substances to be absorbed and retained in an organism's tissues (i.e., bioaccumulated) at concentrations sufficient to pose health concerns. Substances that exhibit properties that enable biomagnification in the food chain (i.e., amplification of tissue concentrations at successive trophic levels) are of particular concern due to the elevated long-term exposures these substances pose to higher trophic organisms, including humans. Historically, biomarkers of in vivo chemical exposure (e.g., eggshell thinning, bill deformities) retrospectively led to the identification of such compounds, which were later categorized as persistent organic pollutants. Today, multiple bioaccumulation metrics are available to quantitatively assess the bioaccumulation potential of new and existing chemicals and identify substances that, upon or before environmental release, may be characterized as persistent organic pollutants. This paper reviews the various in vivo measurement approaches that can be used to assess the bioaccumulation of chemicals in aquatic or terrestrial species using laboratory-exposed, field-deployed, or collected organisms. Important issues associated with laboratory measurements of bioaccumulation include appropriate test species selection, test chemical dosing methods, exposure duration, and chemical and statistical analyses. Measuring bioaccumulation at a particular field site requires consideration of which test species to use and whether to examine natural populations or to use field-deployed populations. Both laboratory and field methods also require reliable determination of chemical concentrations in exposure media of interest (i.e., water, sediment, food or prey, etc.), accumulated body residues, or both. The advantages and disadvantages of various laboratory and field bioaccumulation metrics for assessing biomagnification potential in aquatic or terrestrial food chains are discussed. Guidance is provided on how to consider the uncertainty in these metrics and develop a weight-of-evidence evaluation that supports technically sound and consistent persistent organic pollutant and persistent, bioaccumulative, and toxic chemical identification. Based on the bioaccumulation information shared in 8 draft risk profiles submitted for review under the United Nations Stockholm Convention, recommendations are given for the information that is most critical to aid transparency and consistency in decision making. [source] In situ-based effects measures: Determining the ecological relevance of measured responsesINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 2 2007Donald J Baird Abstract The aim of this review is to examine how the choice of test species and study design employed in the use of in situ approaches in ecological risk assessment can maximize the ecological relevance of data. We provide a framework to define and assess ecological relevance that permits study designs to remain focused on the ecological question being addressed. This framework makes explicit the linkages between effects at lower levels of biological organization and higher-order ecological effects at the population, community, and ecosystem levels. The usefulness of this framework is illustrated by reference to specific examples from aquatic ecotoxicology. The use of models as both interpretive and predictive tools is discussed, with suggestions of appropriate methods for different protection goals. [source] Aquatic risks of pesticides, ecological protection goals, and common aims in european union legislationINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006Theo CM Brock Abstract This discussion paper presents a framework for spatiotemporal differentiation in ecological protection goals to assess the risks of pesticides in surface waters. It also provides a proposal to harmonize the different scientific approaches for ecotoxicological effect assessment adopted in guidance documents that support different legislative directives in the European Union (Water Framework Directive and Uniform Principles). Decision schemes to derive maximum permissible concentrations in surface water are presented. These schemes are based on approaches recommended in regulatory guidance documents and are scientifically underpinned by critical review papers concerning the impact of pesticides on freshwater organisms and communities. Special attention is given to the approaches based on standard test species, species sensitivity distribution curves, and model ecosystem experiments. The decision schemes presented here may play a role in the "acceptability" debate and can be used as options in the process of communication between risk assessors and risk managers as well as between these risk experts and other stakeholders. [source] A three-year prospective study of adult subjects with gingivitis II: microbiological parametersJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2007R. P. Teles Abstract Aim: To investigate whether the clinical benefits obtained with a periodontal prevention programme in subjects with periodontal health or minimal disease were accompanied by beneficial changes in the subgingival microbiota. Material and Methods: One hundred and twenty-four subjects completed the study. Subjects were clinically and microbiologically monitored at baseline, 1, 2 and 3 years. Subgingival plaque samples were taken from the mesiobuccal aspect of every tooth and were analysed for the levels of 40 bacterial species using checkerboard DNA,DNA hybridization (total samples=13,477). The mean counts of each of the 40 test species were calculated for each subject at each time point. Significance of differences over time was sought using the Friedman test. p values were adjusted for multiple comparisons. Results: All clinical parameters, at the microbiologically sampled sites, improved over time. The clinical changes were accompanied by statistically significant decreases in the mean counts of 35 of the 40 test species. Major reductions occurred by year 2 for Actinomyces, Capnocytophaga, Campylobacter, Fusobacterium and Prevotella species. At year 3, there was a modest re-growth of the majority of the species. Conclusions: The clinical improvements obtained through preventive measures were accompanied by a shift to a more host-compatible subgingival microbiota. [source] Relationship of cigarette smoking to the subgingival microbiotaJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2001A. D. Haffajee Abstract Background: The relationship of cigarette smoking to the composition of the subgingival microbiota is not clear. Some studies indicated higher levels of certain species in smokers, while other studies failed to detect differences in the microbiota between subjects with different smoking histories. Thus, the purpose of the present investigation was to examine the prevalence, proportions and levels of the subgingival species in adult subjects who were current, past or never smokers. Method: 272 adult subjects ranging in age from 20,86 years with at least 20 teeth were recruited for study. Smoking history was obtained using a questionnaire. Clinical measures were taken at 6 sites per tooth at all teeth excluding third molars at a baseline visit. Subgingival plaque samples were taken from the mesial surface of all teeth excluding third molars in each subject at baseline and assayed individually for counts of 29 subgingival species using checkerboard DNA-DNA hybridization. Subjects were subset according to smoking history into never (n=124), past (n=98) and current smokers (n=50). Uni-variate and multi-variate analyses were used to seek associations between smoking category and the counts, proportions and prevalence of subgingival species. Results: Greater differences were observed for the prevalence (% of sites colonized) of the test species in the 3 smoking groups than were observed for counts or proportions of total counts. Members of the orange and red complexes including E. nodatum, F. nucleatum ss vincentii, P. intermedia, P. micros, P. nigrescens, B. forsythus, P. gingivalis and T. denticola were significantly more prevalent in current smokers than in the other 2 groups. The difference in prevalence between smokers and non-smokers was due to greater colonization at sites with pocket depth <4 mm. Stepwise multiple linear regression analysis indicated that combinations of the prevalence of 5 microbial species and pack years accounted for 44% of the variance for mean pocket depth (p<0.000001), while the prevalence of 3 microbial taxa along with age, pack years, current smoking and gender accounted for 31% of the variance in mean attachment level (p<0.000001). The difference in prevalence between current and never smokers of all members of the red complex and 8 of 12 members of the orange complex was significantly greater in the maxilla than in the mandible. Conclusions: The major difference between the subgingival microbiota in subjects with different smoking history was in the prevalence of species rather than counts or proportions. The greater extent of colonization in smokers appeared to be due to greater colonization at pocket depths <4 mm. Differences in colonization patterns between current and never smokers were greater in the maxilla than in the mandible. Zusammenfassung Grundlagen: Die Beziehung zwischen dem Zigarettenrauchen und der Zusammensetzung der subgingivalen Mikroflora ist nicht klar. Einige Studien verweisen auf höhere Titer von bestimmten Spezies bei Rauchern, während andere Studien keine Unterschiede in der Mikroflora zwischen Personen mit unterschiedlichem Raucher- oder Nichtraucherverhalten nachweisen konnten. Daher war der Zweck der vorliegenden Studie die Untersuchung von Prävalenz, Anteil und Titer der subgingivalen Spezies bei erwachsenen Patienten, die zur Zeit, früher oder niemals Raucher waren. Methode: Für die Studie wurden 272 erwachsene Patienten im Alter zwischen 20 und 86 Jahren und wenigstens 20 Zähnen rekrutiert. Die Anamnese des Rauchverhaltens wurde under Verwendung eines Fragebogens durchgeführt. Bei einer Eingangsuntersuchung erfolgten die klinischen Messungen an 6 Stellen pro Zahn bei allen Zähnen außer den dritten Molaren. Bei der Eingangsuntersuchung wurden, bei allen Zähnen außer den dritten Molaren, von den Mesialflächen subgingivale Plaqueproben entnommen. Für die einzelnen Flächen wurde die Anzahl von 29 subgingivalen Spezies mittels Schachbrett-DNA-DNA-Hybridisierung bestimmt. Die Patienten wurden entsprechend der Rauchervorgeschichte in folgende Gruppen eingeteilt: niemals (n=124), früher (n=98) und zur Zeit (n=50). Um Assoziationen zwischen den Rauchkategorien und der Anzahl, dem Anteil und der Prävalenz der subgingivalen Spezies herauszufinden wurden eine uni-variate und multi-variate Analyse verwendet. Ergebnisse: Es wurden größere Unterschiede zwischen den 3 Gruppen hinsichtlich der Prävalenz der Testspezies (% der Taschen die kolonisiert waren) beobachtet als bei der Anzahl oder dem Anteil an der Gesamtzahl der Keime beobachtet wurde. Die Prävalenz der Keime des orangen und roten Komplexes einschließlich. E. nodatum, F. nucleatum ss vincentii, P. intermedia, P. micros, P. nigrescens, B. forsythus, P. gingivalis und T. denticola war bei den aktuellen Rauchern stärker prävalent als in den anderen beiden Gruppen. Die Differenz in der Prävalenz zwischen Rauchern und Nichrauchern wurde verursacht durch eine stärkere Kolonisation in Taschen mit einer Taschentiefe <4 mm. Die schrittweise multiple lineare Regressionsanalyse zeigte, dass Kombinationen der Prävalenz von 5 mikrobiellen Spezies und der Packungsjahre für 44% der Varianz der mittleren Taschentiefe verantwortlich waren (p<0.000001), während die Prävalenz von 3 mikrobiellen Taxa zusammen mit Alter, Packungsjahre, Raucherstatus und Geschlecht für 31% der Varizna im mittleren Attachmentniveau verantwortlich waren (p<0.000001). Die Differenz in der Prävalenz zwischen den aktuellen Rauchern und den die niemals rauchten war für alle Keime der roten Komplexes und 8 von 12 Keimen des orangen Komplexes im Oberkiefer signifikant größer als im Unterkiefer. Schlussfolgerung: Der Hauptunterschied zwischen der subgingivalen Mikroflora bei Patienten mit unterschiedlicher Rauchervorgeschichte lag mehr bei der Prävalenz der Spezies als bei der Anzahl der Keime oder den Anteilen an der Gesamtflora. Das größere Maß an Kolonisation bei den Rauchern schien durch eine stärkere Kolonisation in Taschen <4 mm verursacht zu sein. Differenzen im Kolonisationsmuster zwischen aktuellen Rauchern und Nichtrauchern die niemals rauchten waren im Oberkiefer größer als im Unterkiefer. Résumé Origine, but: La relation entre l'usage de la cigarette et la composition de la microflore sous gingivale n'est pas claire. Certaines études indiquent d'importants niveaux de certaines espèces chez les fumeurs, alors que d'autres études n'arrivent pas à détecter de différences dans la micrflore entre des sujets ayant des histoires tabagiques différentes. Aussi, le propos de cette recherche est d'examiner la prévalence, les proportions et le niveau des espèces sous gingivales chez des sujets adultes fumeurs, anciens fumeurs ou non-fumeurs. Méthodes: 272 sujets adultes, âgès de 20 à 86 ans, ayant au moins 20 dents furent recrutés pour l'étude. L'histoire tabagique fut obtenue à l'aide d'un questionnaire. Des mesures cliniques furent prises sur 6 sites par dents, sur toutes les dents à l'exception des troisièmes molaires lors de la première visite. Des échantillons de plaque sous gingivale étaient prélevés sur la face mésiale de chaque dent à l'exception des troisièmes molaires chez chaque sujet lors de la première visite et individuellement testés pour le comptage de 29 espèces sousgingivales par hybridisation en damier ADN-ADN. Les sujets étaient groupés en sous ensembles en fonction de leur histoire tabagique en non-fumeurs (n=124), ancien fumeurs (n=98), et fumeurs (n=50). Des analyses monovariées et multivariées furent utilisées pour rechercher des associations entre les catégories de fumerus et les comptages, proportions et prévalences des espèces bactériennes. Résultats: De plus grandes différences étaient observées pour la prévalence (% de sites colonisés) des expèces testées dans les 3 groupes, que pour le comptage ou la proportion des comptages totaux. Les membres des complexes orange et rouge dont E. nodatum, F. nucléatum ss vicentii, P. intermedia, P. micros, P. nigrescens, B. forsythus, P. gingivalis, et T. denticolaétait significativement plus prévalent chez les fumeurs que dans les 2 autres groupes. La différence de prévalence entre les fumeurs et les non-fumeurs était due à une plus grande colonisation des sites dont la profondeur de poche était <4 mm. L'analyse par régression linéaire multiple stepwise indiquait que les combinaisons de la prévalence de 5 espèces microbiennes et les paquets-années comptaient pour 44% de la variance pour la moyenne de profondeur de poche (p<0.000001), alors que la prévalence de 3 taxons microbiens avec l'âge, les paquets-années, le tabagisme présent et le sexe comptaient pour 31% de la variance pour le niveau d'attache moyen (p<0.000001). La différence de prévalence entre les fumerus en activité et les non-fumeurs (jamais fumé) de tous les membres du complexe rouge et de 8 des 12 membres du complexe orange était significativement plus élevée au maxillaire qu'à la mandibule. Conclusions: La différence majeure entre les microflores sous gingivales chez les sujets ayant des histoires tabagiques différentes se trouvaient dans la prévalence des expèces plutôt que dans leurs quantité ou leurs proportions. La plus grande importance de colonisation chez les fumerus apparaît être dûe à une colonisation plus grande dans les poches <4 mm. Des différences des caractéristiques de colonisation entre les fumerus actifs et les personnes n'ayant jamais fuméétaient plus importantes au maxillaire qu'à la mandibule. [source] Amoxicillin plus metronidazole in the treatment of adult periodontitis patientsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2001A double-blind placebo-controlled study Abstract Background, aims: The aim of this double-blind, parallel study was to evaluate the adjunctive effects of systemically administered amoxicillin and metronidazole in a group of adult periodontitis patients who also received supra- and subgingival debridement. Methods: 49 patients with a diagnosis of generalised severe periodontitis participated in the study. Random assignment resulted in 26 patients in the placebo (P) group with a mean age of 40 years and 23 patients in the test (T) group which had a mean age of 45 years. Clinical measurements and microbiological assessments were taken at baseline and 3 months after completion of initial periodontal therapy with additional placebo or antibiotic treatment. Patients received coded study medication of either 375 mg amoxicillin in combination with 250 mg metronidazole or identical placebo tablets, every 8 hours for the following 7 days. Results: At baseline, no statistically significant differences between groups were found for any of the clinical parameters. Except for the plaque, there was a significantly larger change in the bleeding, probing pocket depth (PPD) and clinical attachment level (CAL) in the T-group as compared to the P-group after therapy. The greatest reduction in PPD was found at sites with initial PPD of 7 mm, 2.5 mm in the P-group and 3.2 mm in the T-group. The improvement in CAL was most pronounced in the PPD category 7 mm and amounted to 1.5 mm and 2.0 mm in the P- and T-groups, respectively. No significant decrease was found in the number of patients positive for any of the test species in the P-group. The number of patients positive for Porphyromonas gingivalis, Bacteroides forsythus and Prevotella intermedia in the T-group showed a significant decrease. After therapy there was a significant difference between the P- and the T- group in the remaining number of patients positive for P. gingivalis, B. forsythus and Peptostreptococcus micros. 4 subgroups were created on the basis of the initial microbiological status for P. gingivalis positive (Pg-pos) and negative patients (Pg-neg) in the P- and the T-groups. The difference in reduction of PPD between Pg-pos and Pg-neg patients was particularly evident with respect to the changes in % of sites with a probing pocket depth 5 mm. This % decreased from 45% at baseline to 23% after treatment in the Pg-pos placebo subgroup and decreased from 46% to 11% in the Pg-pos test subgroup (p0.005). In contrast, the changes in the proportions of sites with a probing pocket depth 5 mm in the Pg-neg placebo and Pg-neg test subgroup were similar, from 43% at baseline to 18% after treatment versus 40% to 12%, respectively. Conclusions: This study has shown that systemic usage of metronidazole and amoxicillin, when used in conjunction with initial periodontal treatment in adult periodontitis patients, achieves significantly better clinical and microbiological results than initial periodontal treatment alone. Moreover, this research suggests that especially patients diagnosed with P. gingivalis benefit from antibiotic treatment. Zusammenfassung Zielsetzung: Das Ziel dieser placebokontrollierten Doppelblindstudie mit parallelen Gruppen war es, die zusätzlichen Effekte der systemischen Gabe von Amoxicillin und Metronidazol bei Patienten mit Erwachsenenparodontitis zu untersuchen, bei denen auch eine supra- und subgingivale Instrumentierung durchgeführt worden war. Material und Methoden: 49 Patienten mit einer generalisierten schweren Erwachsenenparodontitis nahmen an der Studie teil. Zufällige Zuweisung der Therapien führte zu 26 Patienten in der Placebo-Gruppe (P) mit einem mittleren Alter von 40 und 23 Patienten in der Test-Gruppe (T) mit einem mittleren Alter von 45 Jahren. Klinische Messungen und mikrobiologische Untersuchungen wurden zu Beginn der Therapie sowie 3 Monate nach parodontaler Initialbehandlung mit zusätzlicher Placebo- bzw. Antibiotikagabe durchgeführt. Nachdem alle Zähne mit pathologisch vertieften Taschen subgingival instrumentiert worden waren, erhielten die Patienten eine kodierte Studienmedikation, die entweder aus 375 mg Amoxicillin und 250 mg Metronidazol oder identisch aussehenden Placebotabletten bestand, die die Patienten für 7 Tage alle 8 Stunden einnehmen sollten. Ergebnisse: Zu Beginn der Studie bestand kein statistisch signifikanter Unterschied zwischen den Versuchsgruppen hinsichtlich klinischer Parameter. Nicht für den Plaque Index, aber für Sondierungsblutung, Sondierungstiefen (ST) und klinische Attachmentlevel (PAL) kam es in der T-Gruppe zu signifikant stärkeren Veränderungen im Vergleich zur P-Gruppe. Die stärkste ST-Reduktion bzw. die größten Attachmentgewinne wurden bei Stellen gefunden, die initial ST 7 mm aufgewiesen hatten: P-Gruppe: ST=2.5 mm, PAL=1.5 mm; T-Gruppe: ST=3.2 mm, PAL=2.0 mm. Für keines der untersuchten Parodontalpathogene wurde eine signifikante Reduktion in der P-Gruppe beobachtet, während sich in der T-Gruppe eine signifikante Reduktion für Porphyromonas gingivalis, Bacteroides forsythus und Prevotella intermedia ergab. Nach Therapie ergab sich ein statistisch signifikanter Unterschied zwischen T- und P-Gruppe hinsichtlich Persistenz von P. gingivalis, B. forsythus und Peptostreptococcus micros. Entsprechend dem initialen mikrobiologischen Status für P. gingivalis wurden 4 Untergruppen gebildet: P. gingivalis positive (Pg+) oder (Pg,) Patienten in der T-bzw. P-Gruppe. Der Unterschied zwischen Pg+ und Pg, Patienten war besonders groß hinsichtlich der Veränderung des %-Anteils der Stellen mit ST5 mm. Dieser verringerte sich in der Pg+ P-Untergruppe von 45% auf 23% und in der Pg+ T-Untergruppe von 46% auf 11% (p0.005). Im Unterschied dazu war die Reduktion des Anteils der ST 5 mm in der Pg, P- und T-Untergruppen gleich: P-Gruppe: 43% auf 18%; T-Gruppe von 40% auf 12%. Schlußfolgerungen: Die systemische Gabe von Amoxicillin und Metronidazol zusätzlich zu subgingivaler Instrumentierung bei Patienten mit Erwachsenenparodontitis führt zu signifikant günstigeren klinischen und mikrobiologischen Ergebnissen als die konventionelle Therapie allein. Insbesondere Patienten mit P. gingivalis scheinen von dieser unterstützenden antibiotischen Therapie zu profitieren. Résumé Le but de cette étude parallèle en double aveugle était d'évaluer les effets supplémentaires apportés par l'administration d'amoxicilline et de metronidazole dans un groupe de patients atteints de parodontite de l'adulte qui ont reçu également un débridement supra et sous gingival. 49 patients présentant un diagnostic de parodontite généralisée sévère participèrent à l'étude. La composition des groupes sélectionnés au hasard, était de 26 patients dans le groupe placebo (P) avec un âge moyen de 40 ans et 23 patients dans le groupe test (T) avec une moyenne d'âge de 45 ans. Des mesures cliniques et des prélèvements microbiologiques étaient réalisés initialement et 3 mois après la fin de la thérapeutique parodontale initiale complétée par un placebo ou un traitement antibiotique. Les patients recevaient des médicaments codés pour l'étude de 375 mg amoxicilline combiné avec 250 mg de metronidazol ou des comprimés placebo identiques, toutes les 8 heures pendant les 7 jours suivants. Initalement, aucune différence statistiquement significative entre les groupes n'était observée, pour aucun des paramètres cliniques. En dehors de la plaque, il y avait une modification plus élevée significative pour le saignement, la profondeur de poche au sondage (PPD) et le niveau clinique d'attache (CAL) dans le groupe T, par rapport au groupe P, après traitement. La plus grande réduction pour PPD était observée pour les sites ayant une profondeur de poche au sondage intiale>ou égale à 7 mm, 2.5 mm dans le groupe P et 3.2 mm dans le groupe T. L'amélioration du CAL était plus prononcée pour la catégorie >ou égale à 7 mm et allait jusqu'à 1.5 et 2.0 mm dans les groupes P et T, respectivement. Aucune diminution significative n'était trouvée pour le nombre de patients positifs pour n'importe quelle espèce test dans le groupe P. Le nomber de patients positifs pour Porphyromonas gingivalis, Bacteroides forsythus et Prevotella intermedia dans le groupe T présentait une diminution significative. Après thérapeutique, il y avait une différence significative entre les groupe P et T, en ce qui concerne le nombre de patients positifs pour P. gingivalis, B. forsythus et Peptostreptococcus micros. 4-sous groupes furent créés sur la base de l'état microbiologique pour les patients positifs àP. gingivalis (Pg-pos), et négatifs (Pg-neg), dans les groupes P et T. La différence de réduction de PPD entre les patients Pg-pos et Pg-neg était particulièrement évidente en ce qui concernait les changements en % de sites présentant une profondeur de poche au sondage >ou égale à 5 mm. Ce % diminuait de 45% initialement à 23% après traitement dans le sous-groupe Pg-pos placebo et de 46% à 11% dans le sous-groupe Pg-pos test (p<0.005). A l'inverse, les changements observés dans les proportions de sites avec une profondeur de poche au sondage >5 mm dans les sous-groupes Pg-neg placebo et Pg-neg test étaient similaires, de 43% initialement à 18% après traitement contre 40% à 12% respectivement. En conclusion, cette étude a montré que l'utilisation systèmique de metronidazole et d'amoxicilline, lorsqu'elle est utilisée en complément du traitement parodontal initial chez des patients atteints de parodontite de l'adulte, donne, de façon significative, de meilleurs résultats cliniques et microbiologiques qu'un traitement parodontal initial seul. De plus, cette recherche suggère que les patients porteurs du P. gingivalis bénéficient particulièrement d'un traitement antibiotique. [source] The effect of repeated professional supragingival plaque removal on the composition of the supra- and subgingival microbiotaJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2000Laurie Ann Ximénez-Fyvie Abstract Background, aims: The purpose of the present investigation was to determine the effect of weekly professionally administered supragingival plaque removal on the composition of the supra and subgingival microbiota. Methods: 18 adult subjects with periodontitis who had been treated and were in a maintenance phase of therapy were clinically and microbiologically monitored at baseline, 3, 6 and 12 months. After the baseline visit, the subjects received scaling and root planing followed by professional supragingival plaque removal every week for 3 months. Clinical measures of plaque accumulation, bleeding on probing (BOP), gingival redness, suppuration, pocket depth and attachment level were made at 6 sites per tooth at each visit. Separate supra (N=1804) and subgingival (N=1804) plaque samples were taken from the mesial aspect of all teeth excluding third molars in each subject at each time point and evaluated for their content of 40 bacterial taxa using checkerboard DNA-DNA hybridization. Significance of changes in mean counts, prevalence and proportions of bacterial species over time in both supra and subgingival samples were determined using the Quade test and adjusted for multiple comparisons. Results: Mean % of sites exhibiting plaque, gingival redness and BOP were significantly reduced during the course of the study. Significant decreases in mean counts were observed in both supra and subgingival samples. Mean total DNA probe counts (×105, ±SEM) at baseline, 3, 6 and 12 months were: 133±19, 95±25, 66±6, 41±6 (p<0.001) for supragingival samples and 105±22, 40±10, 19±4, 13±3 (p<0.001) for subgingival samples. Mean counts of 22 of 40 and 34 of 40 species tested were significantly reduced in the supra and subgingival samples respectively over the monitoring period. For example, mean counts of Porphyromonas gingivalis×105 at baseline, 3, 6 and 12 months in the subgingival plaque samples were 2.0±0.4, 0.5±0.2, 0.6±0.3, 0.3±0.1 (p<0.001); Bacteroides forsythus 2.0±0.6, 0.4±0.1, 0.4±0.2, 0.1±0.2 (p<0.001); Treponema denticola 3.4±1.1, 0.8±0.3, 0.4±0.2, 0.3±0.3 (p<0.01). Similar reductions were seen in supragingival plaque samples. While counts were markedly reduced by professional plaque removal, the proportion and prevalence of the 40 test species were marginally affected. Conclusions: Weekly professional supragingival plaque removal profoundly diminished counts of both supra- and subgingival species creating a microbial profile comparable to that observed in periodontal health. This profile was maintained at the final monitoring visit, 9 months after completion of therapy. [source] Factors affecting human supragingival biofilm composition.JOURNAL OF PERIODONTAL RESEARCH, Issue 4 2009Background and Objective:, Little is known regarding the factors that affect the microbial composition of supragingival biofilms. This study was designed to test the hypothesis that tooth location affects the microbial composition of supragingival plaque beyond the effect due to plaque mass as reflected by total DNA probe count. Material and Methods:, Supragingival plaque samples were taken from the mesiobuccal aspect of each tooth in 187 subjects (n = 4745 samples). All samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA,DNA hybridization. Significance of differences in mean species counts and proportions were determined among tooth surfaces and six tooth type categories: molars, bicuspids, incisors/canines in the mandible and maxilla separately using the Kruskal,Wallis test. Stepwise multiple linear regression was employed to examine the relationship between species proportions and total DNA probe count, tooth location, periodontal and smoking status, age and sex. Results:, All species differed significantly among tooth types and among the six tooth categories. Higher plaque levels were seen on molars and lower incisors. Some differences observed between tooth types could be partly explained by the level of plaque. Teeth with high plaque mass exhibited high levels of Capnocytophaga gingivalis, Actinomyces naeslundii genospecies 2, Campylobacter rectus and Campylobacter showae. However, certain species, such as Veillonella parvula and Streptococcus sanguinis, differed significantly at different tooth locations despite similarities in plaque mass. Twenty of the test species exhibited a significant association with tooth location after adjusting for total DNA probe count and subject level factors. Conclusion:, While plaque mass was associated with differences in proportions of many species in supragingival biofilms, tooth location also was strongly associated with species proportions in both univariate and multivariate analyses. [source] Biofilms in the Edentulous Oral CavityJOURNAL OF PROSTHODONTICS, Issue 5 2008Amit Sachdeo BDS, DMSc Abstract Purpose: The oral cavity presents numerous surfaces for microbial colonization. These surfaces produce biofilms of differing complexities unique to each individual. Several studies have looked at biofilms in dentate patients. There has been limited research regarding biofilms on dentures or soft tissues of edentulous patients. The purpose of the present investigation was to provide meaningful data describing microbial ecological relationships in the oral cavity of edentulous patients and to evaluate the microbiota on hard and soft tissue surfaces and saliva in edentulous patients wearing complete dentures. Materials and Methods: Sixty-one edentulous subjects with complete maxillary and mandibular dentures were recruited. "Supragingival" biofilm samples were taken from 28 denture teeth for each subject. Biofilm samples were also taken from the dorsal, lateral, and ventral surfaces of the tongue, floor of mouth, buccal mucosa, hard palate, vestibule/lip, "attached gingiva," and saliva. Samples were individually analyzed for their content of 41 bacterial species using checkerboard DNA,DNA hybridization. Levels and proportions of each species were determined for every sample location. Results: Periodontal pathogens such as Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were clearly present in the samples from the edentulous subjects. Microbial profiles in samples from the soft tissue surfaces differed among site locations. Samples from the dorsum of the tongue exhibited the highest bacterial counts followed by the "attached gingiva" and the lateral surfaces of the tongue, while the lowest mean counts were found in samples from the buccal mucosa and labial vestibules. Using cluster analysis of the proportions of the test species, three clusters were formed. The first cluster comprised saliva, supragingival plaque, and the lateral and dorsal surfaces of the tongue. The second cluster comprised the other six soft tissue surfaces. Species on the denture palate formed a third cluster. Conclusions: One of the major findings in this study was the detection of periodontal pathogens, A. actinomycetemcomitans and P. gingivalis, in the edentulous subjects, as these species were thought to disappear after removal of all natural teeth. This finding has implications regarding future dental treatment and the general health of individuals. Distinct patterns of microbial colonization were seen on the different soft tissue surfaces. Thus, this investigation provided the first step in defining the organisms that are associated with edentulous patients on both soft (mucosa) and hard surfaces (denture). The study also provided meaningful data that described microbial ecological relationships in the oral cavity of edentulous subjects. The authors believe that this study is the first comprehensive assessment of the microbiota in the complete denture-wearing subject. [source] DNA barcoding in Tardigrada: the first case study on Macrobiotus macrocalix Bertolani & Rebecchi 1993 (Eutardigrada, Macrobiotidae)MOLECULAR ECOLOGY RESOURCES, Issue 3 2009MICHELE CESARI Abstract Morphological and molecular studies on a tardigrade species have been carried out to verify the possibility of using a DNA barcoding approach for species identification in this phylum. Macrobiotus macrocalix Bertolani & Rebecchi, 1993 was chosen as the test species since it belongs to a group of species in which the taxonomy is quite problematic. Animals and eggs belonging to three Italian and one Swedish populations have been investigated. Both morphological and molecular analyses show that all the populations belong to the same species. The low genetic distances recorded among the studied populations (0.3,1.0%) and the high genetic distance (15.9,16.3%) between these populations and a closely related species confirm the possibility of identifying a specimen of this species by its cytochrome oxidase subunit I sequence. Data from other authors support our results indicating that DNA barcoding can be applied to tardigrades. With our protocols, we have obtained voucher specimens that enable us to show a correspondence between morphology and molecular data. [source] The microbiota on different oral surfaces in healthy childrenMOLECULAR ORAL MICROBIOLOGY, Issue 3 2009W. Papaioannou Introduction:, Knowledge of the early oral colonization patterns could provide a better understanding of oral biofilm development and disease initiation that in turn could be the basis for early preventive programmes. Methods:, Microbial samples were collected from five different oral habitats from a total of 93 children (age 3,12 years), attending the Dental School of the University of Athens, who were split into three age groups. A total of 38 microbial species were sought out by the checkerboard DNA,DNA hybridization technique. Results:, All of the test species, except Parvimonas micra and Porphyromonas gingivalis, differed significantly among sample locations providing quite distinct microbial profiles for the different oral surfaces. Supragingival and subgingival plaque had similar profiles and exhibited higher proportions of Actinomyces species and Green complex while soft tissue samples were dominated by streptococci of the Yellow complex. The profiles of the tongue dorsum and saliva were also similar. Many of the species were in similar proportions in all three age groups for a given location. Periodontal pathogens showed increases in proportions with increasing age. Specifically, the Red complex species (Tannerella forsythia, P. gingivalis, Treponema denticola) showed a significant increase in proportion with age (P < 0.05) in all sample locations. Conclusions:, The results showed a pattern of colonization in children similar to that previously found in adults. Differences in the profile between age groups suggest a gradual maturation of the oral microbiota, with it being made up of an increasing number of Orange and Red complex species. [source] Artificial Dispersal as a Restoration Tool in Meadows: Sowing or Planting?RESTORATION ECOLOGY, Issue 2 2009Lotta Wallin Abstract Habitat fragmentation and the abandonment of former agricultural practices have led to extremely low dispersal rates for plant species growing in traditionally managed hay meadows in Sweden. Historically, seed dispersal between populations was maintained by hay movement, grazing animals, and farmers sharing their equipment. Because these means of dispersal typically are no longer occurring, artificial dispersal using seeds and plug-plants is tested here as a restoration tool. In this study, we chose two perennial herbs commonly occurring in meadows as test species, viz, Hypochoeris maculata L. (Asteraceae) and Succisa pratensis Moench. (Dipsacaceae). We found that plug-plant transplants were twice as effective as seed sowing for both species. The seed collection site was found to be important for seed-based establishment and survival; consequently, the choice of donor meadow is important when acquiring seeds used for restoration. We also found that survival of plants introduced as seeds was generally lower at sites harboring species favored by nitrogen as well as at sites in later successional phases. Both methods of introducing meadow species worked well, even though long-term establishment may well be more successful with the plug-plant method due to higher plug-plant establishment 2 years after introduction in the field. [source] Riparian Forest Restoration: Increasing Success by Reducing Plant Competition and HerbivoryRESTORATION ECOLOGY, Issue 2 2002Bernard W. Sweeney Abstract The reestablishment of riparian forest is often viewed as "best management practice" for restoring stream ecosystems to a quasi-natural state and preventing non-point source contaminants from entering them. We experimentally assessed seedling survivorship and growth of Quercus palustris (pin oak), Q. rubra (red oak), Q. alba (white oak), Betula nigra (river birch), and Acer rubrum (red maple) in response to root-stock type (bare root vs. containerized), herbivore protection (tree shelters), and weed control (herbicide, mowing, tree mats) over a 4-year period at two riparian sites near the Chester River in Maryland, U.S.A. We started with tree-stocking densities of 988/ha (400/ac) in the experimental plots and considered 50% survivorship (i.e., a density of 494/ha [200/ac] at crown closure) to be an "acceptable or minimum" target for riparian restoration. Results after four growing seasons show no significant difference in survivorship and growth between bare-root and containerized seedlings when averaged across all species and treatments. Overall survivorship and growth was significantly higher for sheltered versus unsheltered seedlings (49% and 77.6 cm vs. 12.1% and 3.6 cm, respectively) when averaged across all species and weed control treatments. Each of the five test species exhibited significantly higher 4-year growth with shelter protection when averaged across all other treatments, and all species but river birch had significantly higher survivorship in shelters during the period. Seedlings protected from weeds by herbicide exhibited significantly higher survivorship and growth than seedlings in all other weed-control treatments when averaged across all species and shelter treatments. The highest 4-year levels of survivorship/growth, when averaged across all species, was associated with seedlings protected by shelters and herbicide (88.8%/125.7cm) and by shelters and weed mats (57.5%/73.5 cm). Thus, only plots where seedlings were assisted by a combination of tree shelters and either herbicide or tree mats exhibited an "acceptable or minimum" rate of survivorship (i.e.,>50%) for riparian forest restoration in the region. Moreover, the combined growth and survivorship data suggest that crown closure over most small streams in need of restoration in the region can be achieved most rapidly (i.e., 15 years or less) by protecting seedlings with tree shelters and controlling competing vegetation with herbicides. [source] Effects of extrusion processing of feed ingredients on apparent digestibility coefficients of nutrients for rainbow trout (Oncorhynchus mykiss)AQUACULTURE NUTRITION, Issue 2 2003Zongjia J. Cheng Abstract An experiment was conducted to evaluate the effects of extrusion processing on apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude fat, energy and minerals in soya bean meal (SBM), barley, corn gluten meal and whole wheat, using rainbow trout Oncorhynchus mykiss as the test species. In addition, availabilities of amino acids were also determined in SBM. Feed ingredients were preconditioned at 89,93 °C and then extruded using a Wenger X-85 extruder. Nonextruded ingredients were used as is, meaning that they were not preconditioned. The extruded and nonextruded ingredients were mixed with a casein,gelatin reference diet at 3 : 7 ratio prior to determination of ADC values. A total of 135 trout (initial mean body weight 223.4 ± 12.7 g) were stocked into nine 140-L fibreglass digestibility tanks with 15 fish per tank. Individual tanks were assigned randomly to each of eight diets made from the four ingredients (extruded and nonextruded) plus the reference diet. After faeces were collected in the first week, the diets were switched among tanks, and faeces were collected again after 5-day acclimation period in the second week. Yttrium oxide was used as the inert marker. Results showed that extrusion processing significantly improved ADCs of dry matter, crude fat and gross energy, and reduced ADCs of crude protein, phosphorus, copper, iron and zinc. Results also showed that the effects of extrusion processing on chemical composition and ADCs of nutrients depended on the ingredients. It is recommended that trace minerals such as copper, iron and zinc be supplemented by an additional 10,20% when rainbow trout diets are extruded because of their reduced bioavailability in plant meal-based feed ingredients. [source] Chemical Characterization of New Oxylipins from Cestrum parqui, and Their Effects on Seed Germination and Early Seedling GrowthCHEMISTRY & BIODIVERSITY, Issue 9 2008Antonio Fiorentino Abstract Isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from Cestrum parqui L',Hérl. is reported. All the structures were elucidated on the basis of their spectral data, especially 1D- (1H- and 13C-NMR, DEPT) and 2D-NMR (COSY, TOCSY, HSQC, HMBC, and NOESY). The configurations of the stereogenic C-atoms were determined by the Mosher's method. The compounds have been assayed for their phytotoxicity on Lactuca sativa at concentrations ranging between 10,4 and 10,8,M. The results of the phytotoxicity tests on the germination and growth of the test species, obtained by a cluster analysis, showed interesting relationship between the chemical structures of the compounds and their biological effects. 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