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  • Electron microscopy  (1,196)
  • 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
  • Bacteria
  • Springer  (1,365)
  • Freshwater Biological Association  (30)
  • Lagos (Nigeria)  (6)
  • Istituto Nazionale di Geofisica e Vulcanologia  (5)
  • American Chemical Society
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  • 1
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    Springer Nature | Springer
    Publication Date: 2024-04-05
    Description: This open access book offers a comprehensive overview of the role and potential of microorganisms in the degradation and preservation of cultural materials (e.g. stone, metals, graphic documents, textiles, paintings, glass, etc.). Microorganisms are a major cause of deterioration in cultural artefacts, both in the case of outdoor monuments and archaeological finds. This book covers the microorganisms involved in biodeterioration and control methods used to reduce their impact on cultural artefacts. Additionally, the reader will learn more about how microorganisms can be used for the preservation and protection of cultural artefacts through bio-based and eco-friendly materials. New avenues for developing methods and materials for the conservation of cultural artefacts are discussed, together with concrete advances in terms of sustainability, effectiveness and toxicity, making the book essential reading for anyone interested in microbiology and the preservation of cultural heritage.
    Keywords: Microbiology ; Cultural Heritage ; Microbial Ecology ; Microbial Genetics and Genomics ; Enzymology ; Applied Microbiology ; Microbial Genetics ; Industrial Microbiology ; Open Access ; Restoration ; Conservation ; Biodeterioration ; Bioweathering ; Bioremediation ; Biocleaning ; Biotechnology ; Green Chemistry ; Fungi ; Bacteria ; Artwork ; Antimicrobial protection ; Biocides ; Microbiology (non-medical) ; Cultural studies ; Social & cultural history ; Ecological science, the Biosphere ; Genetics (non-medical) ; Biochemistry ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSG Microbiology (non-medical) ; thema EDItEUR::J Society and Social Sciences::JB Society and culture: general::JBC Cultural and media studies::JBCC Cultural studies ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAF Ecological science, the Biosphere ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSB Biochemistry
    Language: English
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  • 2
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4787 | 1256 | 2011-09-29 15:54:01 | 4787 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: Many sides of the biology of Polyphemus pediculus are adequately studied at the present time. Most complicated is the question of its feeding. Dissection does not give an idea of the composition of the food, since Polyphemus strongly grinds its food with its mandibles. For clarification of the composition of the food of Polyphemus pediculus, the authors carried out in July and August 1962 a series of experiments with the application of radio-carbon methods in order to judge the degree of utilization of one or other foods by the quantity of C14, accumulated in the body of the crustacean after feeding. Particular attention in these experiments was given to the question of the possibility of the utilization by polyphemus of plant food - bacteria, algae and detritus.
    Description: Translated from Russian into English
    Keywords: Biology ; Ecology ; Limnology ; Freshwater crustaceans ; Food composition ; Feeding ; Algae ; Carbon 14 ; Bacteria ; Detritus ; Polyphemus pediculus
    Repository Name: AquaDocs
    Type: monograph
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  • 3
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4793 | 1256 | 2011-09-29 15:52:47 | 4793 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: Recent research has shown that the biomass of bacteria in lakes and other water-bodies can attain significant values. The huge production of bacteria is brought about by their great rate of reproduction. In a series of cases their biomass exceeds the biomass of phytoplankton. Therefore in a study of the biological productivity of water bodies it is necessary to calculate the biomass and production not only of the phyto- and zooplankton, but also of bacteria.The authors uses different methods and formulae to to compare the time of one generation of the bacteria.
    Description: Translated from Russian into English
    Keywords: Biology ; Ecology ; Limnology ; Bacteria ; Biomass ; Formulae ; Growth rate ; Russia ; Lake Batorin
    Repository Name: AquaDocs
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  • 4
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4812 | 1256 | 2011-09-29 15:51:26 | 4812 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: By now a great deal of work is known concerning the methods of determining the production of bacteria or similar questions; among these the problems of a common terminology is discussed. The article discusses formulae of production of bacterial populations over time.
    Description: Translated into English
    Keywords: Biology ; Limnology ; Bacteria ; Population number ; Formulae ; Terminology
    Repository Name: AquaDocs
    Type: monograph
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  • 5
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4844 | 1256 | 2011-09-29 15:49:32 | 4844 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: A modified method of the Biochemical oxygen demand (BOD)test was applied in order to find out the seasonal changing activity of the nitrifying bacteria in surface waters. Samples were taken from the River Elbe near Teufelsbrueck.
    Description: Translated from German into English
    Keywords: Ecology ; Limnology ; Experimental research ; Dissolved oxygen ; Analytical techniques ; Water analysis ; Nitrification ; Bacteria ; Surface water
    Repository Name: AquaDocs
    Type: monograph
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  • 6
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4848 | 1256 | 2011-09-29 15:49:18 | 4848 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: When dissolved in water, compounds of nitrogen and phosphorus ought to contain the basic assimilated food requirements for autotrophic plants and therefore autotrophic algae. This article summarises the occurrence of nitrogen in water, how species of algae utilize nitrogen and phosphorus forms for growth and the capacities of algae to adapt to environments of different nutrient wealth. This topic has unquestionable importance not only for the purpose of survival of a species but also in deciding indirectly about the stability of ecosystems.
    Description: Translated from Polish into English
    Keywords: Biology ; Chemistry ; Limnology ; Algae ; Nitrogen fixation ; Nitrogen ; Phosphorus ; Nutritional requirements ; Bacteria ; Organic compounds
    Repository Name: AquaDocs
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  • 7
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4856 | 1256 | 2011-09-29 15:48:26 | 4856 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: Pseudomonas aeruginosa has for some time been known as a denitrifier. Pseudomonas aeruginosa was chosen for further studies, because P. aeruginosa occurs abundantly in Plusssee and moreover there are contradictory assertions on the gas products of denitrification by this bacteria. In experimental research the pattern of growth and gas production of Pseudomonas aeruginosa on nutrient broth was studied.
    Description: Translated from German into English
    Keywords: Chemistry ; Ecology ; Limnology ; Experimental research ; Bacteria ; Freshwater lakes ; Growth ; Microbiological culture ; Plusssee
    Repository Name: AquaDocs
    Type: monograph
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  • 8
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4850 | 1256 | 2011-09-29 15:48:48 | 4850 | Freshwater Biological Association
    Publication Date: 2021-07-06
    Description: In a lake the nitrogen compounds are liable to regular cycling in which nitrate is reduced and ammonium oxidised. As a nitrate maximum is regularly established in the upper part of the hypolimnion of a stratified summer lake, the authors have dealt in particular with the oxidising side of the nitrogen cycle. Described here are partial results of the nitrification in Plusssee. The Plusssee was chosen, since it is almost entirely without inflows, and, lying in a wooded basin, is well protected from the wind, and therefore stably stratified. In order to determine the number of autotrophic nitrificants the distribution of the Nitrosomonas and Nitrobacter spores in the lake were analysed. From the estimates on the determination of spore numbers of the heterotrophic nitrificants, 14 species in the pure culture were isolated and examined from morphological, biochemical and taxonomic viewpoints.
    Description: Translated from German into English
    Keywords: Ecology ; Limnology ; Bacteria ; Ammonia ; Freshwater lakes ; Nitrification ; Nitrogen cycle
    Repository Name: AquaDocs
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  • 9
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4884 | 1256 | 2011-09-29 15:46:23 | 4884 | Freshwater Biological Association
    Publication Date: 2021-07-07
    Description: The radioautographic method of determination of the number of autotrophic microorganisms was initially suggested for counting methane-oxidizing bacteria. With the help of this method colonies of hydrogen-oxidizing bacteria are differentiated even more clearly from heterotrophic. Under laboratory conditions it was shown that colonies grown on membrane filters from a pure culture of thionic bacteria on a nutrient medium with radio- active carbonate, give better prints on film. This method was tested by the authors for determining the number of these bacteria in the meromictic Lake Vae de San Juan during the expedition to Cuba in the summer of 1973. The study showed that that the thionic bacteria are found throughout the pelagial. It proved that the thionic bacteria can be well considered in water-bodies by the radioautographic method.
    Description: Translated from Russian into English
    Keywords: Ecology ; Limnology ; Freshwater lakes ; Photography ; Bacteria ; Methodology ; Analytical techniques ; Cuba
    Repository Name: AquaDocs
    Type: monograph
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  • 10
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4903 | 1256 | 2011-09-29 15:44:11 | 4903 | Freshwater Biological Association
    Publication Date: 2021-07-07
    Description: Description of a simple method for counting bacteria with active electron transport systems in water and sediment samples. Sodium succinate, NADH and NADPH served as electron donors. It is possible to see several sites of electron transport in the larger cells. Especially impressive are the plankton-algae, protozoa, and small metazoa. This is a partial translation of the ”method” section only.
    Description: Translated from German into English
    Keywords: Biology ; Limnology ; Water samples ; Bacteria ; Bacterial counters ; Bacterial filtration ; Methodology
    Repository Name: AquaDocs
    Type: monograph
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  • 11
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4964 | 1256 | 2011-09-29 15:39:04 | 4964 | Freshwater Biological Association
    Publication Date: 2021-07-07
    Description: The nitrification in the ocean is influenced by several environmental factors and the importance of these is more or less known. There are very likely many more to be discovered in the study of the interaction of nitrification bacteria and other micro-organisms in the ocean. Some of the factors to be considered will briefly be dealt with in this paper. Then the authors give the results of an incubation experiment in the Baltic Sea and from a detailed study in Gullmarn.
    Description: Translated from Swedish into English
    Keywords: Chemistry ; Ecology ; Oceanography ; Marine ecology ; Nitrification ; Experimental research ; Sediment analysis ; Bacteria ; Carbon fixation ; Nitrosococcus oceanus ; Nitrococcus mobilis
    Repository Name: AquaDocs
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  • 12
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4967 | 1256 | 2011-09-29 15:36:52 | 4967 | Freshwater Biological Association
    Publication Date: 2021-07-07
    Description: Utilization of the heavy isotope of nitrogen as a tracer has found numerous applications in soil biology. It allows better definition of different stages of the nitrogen cycle, in particular the immobilization-mineralization cycle. In this work, the authors report the results of calculations of natural isotope ratios of nitrogen in samples of water, soil and vegetation prevailing in Dombes and discuss the possibilities of errors and coefficients of fractionation.
    Description: Translated from French into English
    Keywords: Chemistry ; Ecology ; Limnology ; Nitrogen isotopes ; Soils ; Tracers ; Bacteria ; Nitrogen compounds ; France ; Dombes
    Repository Name: AquaDocs
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  • 13
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/4975 | 1256 | 2011-09-29 15:37:31 | 4975 | Freshwater Biological Association
    Publication Date: 2021-07-07
    Description: Despite the fact that it is a long time sinc e the methods of collection and quantitative estimatio n of protozoa were worked out data on the abundance of these animals in freshwaters are not very numerous. Nevertheless, Infusoria and Rhizopoda at high densities are widespread in the water and sediments of lakes and reservoirs. In order to find ou t the importance of infusoria as a food source for cyclopoids we carried out experimental investigations using C14. For this three species of cyclopoids, widely distributed in open regions of Rybinsk reservoir were selected: Cyclops vicinus, Mesocyclops oithonoides and Kesocyclops leuckarti. The data presented give evidence that the species investigated are able as predators to consume infusorian plankton arid bacteria in the form of flocs or small clumps of detritus.
    Description: Translated from Russian into English
    Keywords: Ecology ; Limnology ; Freshwater lakes ; Freshwater crustaceans ; Feeding experiments ; Bacteria ; Feeding ; Russia ; Cyclops vicinus ; Mesocyclops oithonoides ; Kesocyclops leuckarti
    Repository Name: AquaDocs
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  • 14
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5287 | 1256 | 2011-09-29 15:12:00 | 5287 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Restoration of water-bodies from eutrophication has proved to be extremely difficult. Mathematical models have been used extensively to provide guidance for management decisions. The aim of this paper is to elucidate important problems of using models for predicting environmental changes. First, the necessity for a proper uncertainty assessment of the model, upon calibration, has not been widely recognized. Predictions must not be a single time trajectory; they should be a band, expressing system uncertainty and natural variability. Availability of this information may alter the decision to be taken. Second, even with well-calibrated models, there is no guarantee they will give correct projections in situations where the model is used to predict the effects of measures designed to bring the system into an entirely different ”operating point”, as is typically the case in eutrophication abatement. The concept of educated speculation is introduced to partially overcome this difficulty. Lake Veluwe is used as a case to illustrate the point. Third, as questions become more detailed, such as ”what about expected algal composition”, there is a greater probability of running into fundamental problems that are associated with predicting the behaviour of complex non-linear systems. Some of these systems show extreme initial condition sensitivity and even, perhaps, chaotic behaviour, and are therefore fundamentally unpredictable.
    Keywords: Ecology ; Limnology ; Pollution ; Eutrophication ; Algal blooms ; Phytoplankton ; Freshwater lakes ; Models ; Growth ; Modelling ; Equations ; Bacteria ; Prediction ; Netherlands ; Veluwemeer Lake
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  • 15
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5301 | 1256 | 2011-09-29 15:07:11 | 5301 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The cyanobacteria that cause problems in water supply are principally the colonial forms that are buoyed up by gas vesicles. The success of these organisms is due, in part, to their gas vesicles, which enable them to perform vertical migrations or to maintain themselves in the euphotic zone. The gas vesicles are also the root cause of the problems. In calm periods they cause the cyanobacteria to float to the water surface forming noxious scums, and they may prevent the colonies from sedimenting in water treatment plants. Gas vesicles are hollow, gas-filled structures; they are rigid but can be collapsed by the application of pressure. Their critical collapse pressure is influenced by their dimensions, which vary in different organisms. Gas vesicles are formed by the assembly of two types of protein, which determine their mechanical and physical properties. Methods for collapsing gas vesicles in natural populations of cyanobacteria will be considered. They may have application to the control of cyanobacteria in water supply.
    Keywords: Ecology ; Limnology ; Pollution ; Eutrophication ; Algal blooms ; Gases ; Buoyancy ; Algae ; Bacteria ; Photosynthesis ; Growth ; Competition
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  • 16
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5317 | 1256 | 2011-09-29 15:05:35 | 5317 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Most microbiological methods require culture to allow organisms to recover or to selectively increase, and target organisms are identified by growth on specific agar media. Many cultural methods take several days to complete and even then the results require confirmation. Alternative techniques include the use of chromogenic and fluorogenic substances to identify bacteria as they are growing, selective capture using antibodies after short periods of growth, molecular techniques, and direct staining with or without flow cytometry for enumeration and identification. Future microbiologists may not use culture but depend on the use of specific probes and sophisticated detection systems.
    Keywords: Engineering ; Limnology ; Pollution ; Water quality ; Microorganisms ; Methodology ; Detection ; Bacteria ; Cultured organisms ; Enzymes ; Immunofluorescence ; Flow cytometry ; Microbiological culture
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  • 17
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5315 | 1256 | 2011-09-29 15:06:22 | 5315 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Improvements in methods for the detection and enumeration of microbes in water, particularly the application of techniques of molecular biology, have highlighted shortcomings in the ”standard methods” for assessing water quality. Higher expectations from the consumer and increased publicity associated with pollution incidents can lead to an uncoupling of the cycle which links methodological development with standard-setting and legislation. The new methodology has also highlighted problems within the water cycle, related to the introduction, growth and metabolism of microbes. A greater understanding of the true diversity of the microbial community and the ability to transmit genetic information within aquatic systems ensures that the subject of this symposium and volume provides an ideal forum to discuss the problems encountered by both researcher and practitioner.
    Keywords: Biology ; Limnology ; Pollution ; Water quality ; Microbiology ; Microorganisms ; Hydrologic cycle ; Methodology ; Bacteria ; Bacterial counters ; Public health ; Microbial contamination ; Primary production ; Fungi ; Cryptosporidium
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  • 18
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5318 | 1256 | 2011-09-29 15:05:37 | 5318 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: It is widely recognised that conventional culture techniques may underestimate true viable bacterial numbers by several orders of magnitude. The basis of this discrepancy is that a culture in or on media of high nutrient concentration is highly selective (either through ”nutrient shock” or failure to provide vital co-factors) and decreases apparent diversity; thus it is unrepresentative of the natural community. In addition, the non-culturable but viable state (NCBV) is a strategy adopted by some bacteria as a response to environmental stress. The basis for the non-culturable state is that cells placed in conditions present in the environment cannot be recultured but can be shown to maintain their viability. Consequently, these cells would not be detected by standard water quality techniques that are based on culture. In the case of pathogens, it may explain outbreaks of disease in populations that have not come into contact with the pathogen. However, the NCBV state is difficult to attribute, due to the failure to distinguish between NCBV and non-viable cells. This article will describe experiences with the fish pathogen Aeromonas salmonicida subsp. salmonicida and the application of molecular techniques for its detection and physiological analysis.
    Keywords: Ecology ; Limnology ; Pollution ; Bacteria ; Bacterial diseases ; Detection ; Methodology ; Molecular biology ; Microbiological culture
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  • 19
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5316 | 1256 | 2011-09-29 15:05:33 | 5316 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The advent of molecular biology has had a dramatic impact on all aspects of biology, not least applied microbial ecology. Microbiological testing of water has traditionally depended largely on culture techniques. Growing understanding that only a small proportion of microbial species are culturable, and that many microorganisms may attain a viable but non-culturable state, has promoted the development of novel approaches to monitoring pathogens in the environment. This has been paralleled by an increased awareness of the surprising genetic diversity of natural microbial populations. By targeting gene sequences that are specific for particular microorganisms, for example genes that encode diagnostic enzymes, or species-specific domains of conserved genes such as 16S ribosomal RNA coding sequences (rrn genes), the problems of culture can be avoided. Technical developments, notably in the area of in vitro amplification of DNA using the polymerase chain reaction (PCR), now permit routine detection and identification of specific microorganisms, even when present in very low numbers. Although the techniques of molecular biology have provided some very powerful tools for environmental microbiology, it should not be forgotten that these have their own drawbacks and biases in sampling. For example, molecular techniques are dependent on efficient lysis and recovery of nucleic acids from both vegetative forms and spores of microbial species that may differ radically when growing in the laboratory compared with the natural environment. Furthermore, PCR amplification can introduce its own bias depending on the nature of the oligonucleotide primers utilised. However, despite these potential caveats, it seems likely that a molecular biological approach, particularly with its potential for automation, will provide the mainstay of diagnostic technology for the foreseeable future.
    Keywords: Engineering ; Limnology ; Pollution ; Water quality ; Microbiology ; Microorganisms ; Methodology ; Molecular biology ; DNA ; Polymerase chain reaction ; Detection ; RNA ; Bacteria ; Bacterial diseases
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5323 | 1256 | 2011-09-29 15:05:12 | 5323 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: In drinking water distribution systems, three groups of living organisms are usually found in the biofilm and circulating water: heterotrophic bacteria, free-living protozoa, and macro-invertebrates. Indirect evidence suggests that protozoa grazing in distribution systems can partially eliminate biomass production and accidental microbiological pollution. This paper examines the biodiversit in drinking water distribution systems.
    Keywords: Biology ; Limnology ; Water supply ; Biodiversity ; Food chains ; Bacteria ; Invertebrate larvae ; Escherichia coli
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  • 21
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5322 | 1256 | 2011-09-29 15:05:32 | 5322 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The direct measurement of in situ respiring bacteria using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) shows that, especially for Gram-negative bacteria, large numbers of viable but non-culturable (VBNC) bacteria are present in finished water from a conventional water treatment plant, and the regrowth of bacteria along distribution networks can be seen rapidly by using this very sensitive technique. The level of bacterial inactivation with chlorine is much less important than has been previously supposed (based on experiments with non-injured laboratory strains of bacteria and classical culture techniques). Threshold values of VBNC bacteria leaving water treatment plants or regrowing along distribution systems have to be determined for better control of coliform regrowth and health- risks associated with the consumption of drinking water.
    Keywords: Biology ; Health ; Limnology ; Water supply ; Water treatment ; Bacteria ; Microbiological culture ; Bacterial counters ; Staining ; Growth curves ; France
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  • 22
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5333 | 1256 | 2011-09-29 15:04:52 | 5333 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Interest in the identification and characterisation of cyanobacteria and dinoflagellates in aquatic environments is increasing rapidly due to the perceived roles of these organisms in primary production and nuisance aspects in terms of water treatment and public health. Techniques for the identification and quantification of these organisms currently are limited, and the application of molecular approaches provides fundamental taxonomic information and techniques of practical value. Antigenic properties of algal cells may be useful taxonomic markers. Immunodetection techniques utilise the specificity of the antibody/antigen association as a probe for recognising and distinguishing between microorganisms according to their cell- surface chemistry. Immunofluorescent detection of unicellular cyanobacteria and dinoflagellates has been studied with success in marine and freshwater ecosystems and a range of techniques and results are presented and discussed. The most recent advances in the study of planktonic algae have come with the application of continuous flow cytometric methods (CFC). Flow cytometry makes use of the autofluorescence properties of the algal cells, which alone can be used to demonstrate their presence and permit their quantification in natural water samples. When used in conjunction with immunolabelling techniques, the potential of CFC analysis is broadened to study the serological/strain composition of plankters in natural populations. Changes in algal strains represented within and between waters over periods of time are reported and discussed, along with the ecological issues thus raised.
    Keywords: Ecology ; Limnology ; Bacteria ; Methodology ; Algae ; Plankton ; Immunology ; Detection ; Toxicity tests ; Immunofluorescence ; Synechococcus ; Alexandrium tamarens ; Prorocentrum micans
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  • 23
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24208 | 19325 | 2018-05-19 06:39:34 | 24208 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The microbial load of four different fish species from five different market locations in Ibadan metropolis were determined using standard microbiological procedures. The bacteria count of fish sampled from Ojo market was the highest while the bacteria count of the fish sample from Bodija market was the lowest. There was no significant difference (p〈0.05) in the microbial load of the fish sampled from various market locations in Ibadan metropolis. Similarly, there was no significant difference (p〉0.05) in the microbial load on various fish species sold in Ibadan metropolis. The isolated bacteria from the study were: E. coli, Salmonella spp, Klebsiella spp, Staphylococcus aureus, Aerosomonas spp, Pseudomonas spp, Vibrio spp, Serratia spp, Chromobacterium spp, Enterobacteria spp and Shigella spp. The fungi count of fish sampled from Omi markets was the highest while the fungi count of the fish sampled from Ojo market was the lowest. The following fungi were however isolated from the study: Aspergillus flavus, Penicillium spp, Fusarium oxysporum, Trrichoderma spp and Ceotrichium albidium. The study shows that reheating may be necessary to destroy or inactivate micro-organisms in smoked fish before consumption.
    Description: Includes: 2 tables and 2 figures.;Also includes: 17 refernces.
    Keywords: Fisheries ; Nigeria ; Ibadan ; Bacteria ; Fungi ; Market ; Fish species ; freshwater environment ; Microbial contamination ; Microorganisms ; Bacteria ; Freshwater fish ; Cured products ; Sample contamination ; Fungi ; Public health ; Quality assurance ; Disinfection
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24166 | 19325 | 2018-05-13 18:40:22 | 24166 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Probiotics are a promising feed additive to stimulate animal growth and secure a low disease response in aquaculture industry where there are high stocking densities in shrimp and fish production. Fermented locust beans (Parkia biglobosa) are known to be rich in protein and used as food condiment. Probiotic bacteria were isolated from this locally available food material. Culture and characterizations of isolates were carried out. Sugar fermentation patterns were determined by using an API 50 CHL system and incubation were performed anaerobically at 37~'C. MRS broth culture grown at 37~'C overnight was added to 9ml of MRS Agar and the bacteria were incubated at 37~'C for 24 and 48 hrs. Discrete and single colony of lactobacillus was isolated using colony morphology and biochemical tests. The most significant viable taxa isolated was Lactobacillus fermentum at a pH range of (3.0-8.0), while the least viable taxa isolated was Leuconostoc mesenteroides ssp. Microscopically they were Grampositive, rod shaped, non- motile, catalase negative and absence of Endospore.
    Description: Includes: 2 tables and 2 plates.;Also includes: 15 references.
    Keywords: Aquaculture ; Nigeria ; Lagos ; Locust bean ; Probiotics ; Lactobacillus ; Probiotics ; freshwater environment ; Feed ; Additives ; Aquaculture ; Microorganisms ; Bacteria ; Disease resistance ; Fermented products ; Fish culture ; Shrimp culture
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24224 | 19325 | 2018-05-19 07:11:26 | 24224 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Jabi Lake is a natural water body in Abuja Federal Capital Territory (FCT). It was expanded for commercial fishing following relocation of Nigeria's headquarters to Abuja in 1993. Quantitative analysis of microbiological status of water and fish from the Lake was carried out. Samples were collected from the dam site, open water, middle lake and inlet. Result reveal that total coliform count which are indicators of pollution are high (2.0 x 103 cfu/ml, 1.1 x 103 cfu/ml, 1.0 x 103 cfu/ml and 1.1 x 103 cfu/ml for dam site, open water, middle lake, and inlet respectively). Total viable count too is high (9.2 x 103 cfu/ml, 4.9 x 103 cfu/ml, 4.6 x 103 cfu/ml and 4.9 x 103 cfu/ml for dam site, open water, middle lake and inlet respectively). There are no coliform bacteria in the muscle of the fish. High bacterial load is an indication of biological pollution and these calls for restraint on the side of those who are using the lake as site for refuse dump.
    Description: Includes: 10 references.
    Keywords: Fisheries ; Pollution ; Nigeria ; Jabi Lake ; Jabi lake ; Water ; Fish ; Bacteria ; freshwater environment ; Microbiology ; Fish ; Pollution ; Water pollution ; Lake fisheries ; Fishery surveys ; Bacteria ; Baseline studies ; Water sampling ; Microbial contamination ; Muscles ; Freshwater fish ; Pollution surveys ; Water analysis ; Freshwater pollution
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24185 | 19325 | 2018-05-16 14:41:02 | 24185 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Bacteria has been implicated in food poisoning, and smoked fish is not an exception.Generally, fish is highly susceptible to spoilage; therefore this study evaluated the bacteria load in smoked fish from three major locations in Shiroro area of Niger State namely; Gwada, Kuta and Zumba.The smoked fish samples collected from these locations were smeared at both the gills and head regions of the fishes. The bacteria samples identified were Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermis, Pseudomonas aeruginosa, and Samonella typhi, which were common to all the three locations sampled, while only Streptococcus feacaliswas only was found to be present in both Kuta and Zumba location.The frequency of occurrence of these 68 bacteria samples isolated ranges from 8 - 20%, with Bacillius subtilis having the highest occurrence and Pseudomonas aeruginosa have the least occurrence. Out of the total 68 samples, 14 skin samples (20.6%) and 5 gills samples (7.4%) exceeded the acceptable limits of total mesophilic aerobic counts which were 10〈sup〉6〈/sup〉 - 10〈sup〉7〈/sup〉 cfu/g. In the case of total coliform counts, 12 skin samples (17.6%) and 7 gills samples (10.3%) exceeded the acceptable limit which is 4.0 x 102, while in the case of Staphylococcus aureus, 4 skin samples (5.9%) and 2 gills samples (2.9%) exceeded the acceptable limit which is 103 cfu/g. Similarly 3 skin samples (4.4%) and 1 gill sample (1.5%) exceeded the acceptable limit of Salmonella typhi which is 104 cfu/g.
    Description: Includes: 4 tables.;Also includes: 21 references.
    Keywords: Fisheries ; Health ; Escherichia coli ; Bacillus subtilis ; Staphylococcus aureus ; Staphylococcus epidermis ; Pseeudomonas aeruginosa ; Nigeria ; Shiroro L. ; Bacteria ; Smoked (Clarias spp) fish ; Location and recommended values ; brackishwater environment ; freshwater environment ; marine environment ; Bacteria ; Food poisoning ; Cured products ; Fish ; Fish spoilage ; Acceptability ; Lake fisheries ; Gills ; Brain ; Evaluation
    Repository Name: AquaDocs
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    Format: application/pdf
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24222 | 19325 | 2018-05-19 07:06:04 | 24222 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: A total of 2,800 tilapia (Oreochromis niloticus) were stocked in seven duplicates 5 by 4 m2 earthen ponds in NIFFR Integrated Farm, New-Bussa, Niger-State. Raw and sterilized poultry manure of 0.13 to 0.52 kg/m3 concentrations were used to fertilize the ponds with the unfertilized ponds serving as control. The following bacteria were isolated from the cow dung manure; Escherichia coli, E. co1iOl57:H7, Aeromonas hydrophila,Salmonella typhi, Shigella dysenteriae and Staphylococcus aureus. The fish samples from the 0.13 and 0.26 kg/m3 sterilized manure fertilized ponds had zero count in the muscles while samples from other ponds had pathogens in their fish muscles. The study revealed that fish samples from sterilized manures were better in terms of microbial safety for fish productions hence sterilized manure are recommended for use in fish production to ensure the microbial safety of the fish, handlers and that of the consumers.
    Description: includes: 13 references.
    Keywords: Aquaculture ; Oreochromis niloticus ; Escherichia coli ; Aeromonas hydrophila ; Samonela typhi ; Shigella dysenteriae ; Staphylococcus aureus ; Nigeria ; Niger State ; Catfish ; Pathogens ; Microbial quality ; Raw and sterilized manue ; freshwater environment ; Bacteria ; Freshwater fish ; Fish culture ; Fish ponds ; Manure ; Microorganisms ; Freshwater aquaculture ; Aquaculture products ; Food fish ; Quality assurance ; Muscles ; Microbial contamination
    Repository Name: AquaDocs
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    Format: application/pdf
    Format: 278-280
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24596 | 19325 | 2018-05-20 16:13:09 | 24596 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Sixty apparently healthy Heterobranchus bidorsalis and Clarias anguillaris from NIFFR were cultured and 30 each from Monai and wara villages as wild environments were obtained for the studies. The total bacterial load varied from 2.2 x l05 to 1.08 x l08 and 2.27 x 105 to 6.3 x l08 CFU/g of the skin of C. anguillaris and H.bidorsalis in the culture respectively, while the load varied from 1.77 x 105 to 1.17 x l08 and 2.27 x 105 to 9.0 x l07 CFU/g in the wild respectively. Eleven bacterial general species were identified which include: Bacillus species B.firmus, Pseudomonas species, P. aeruginosa, Escherichia coli, Klebsiella aerogenes, K. ozaenae, Staphylococcus aureus, Streptococcus species, S.faecalis, and Aeromonas species. The aims of this investigation is to compare the type and the load of bacteria isolates on the skin of catfish in both culture and wild environment.
    Description: Includes: 7 references.
    Keywords: Aquaculture ; Fisheries ; Clarias anguillaris ; Heterobranchus bidorsalis ; Nigeria ; Kainji L. ; Comparative study ; Bacteria ; Skin ; Clarias ; Heterobranchus ; Kainji Lake ; freshwater environment ; automation
    Repository Name: AquaDocs
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    Format: application/pdf
    Format: 119-122
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5161 | 3949 | 2011-09-29 15:17:51 | 5161 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: Actinomycetes are a group of micro-organisms which lie, in classification, half-way between the fungi and the bacteria. They may be isolated from the plating of leaf washings, water samples and mud dilutions on to nutrient agar (with incorporated actidione to eliminate fungi). The predominant genus varied with the source of the sample. An attempt was also made to isolate the phages of some Actinomycetes. A search was made in the typical environments of the host, for the virus. In this way actinophage were also isolated; and shown to be capable of being transmitted from one host strain to another host strain within 1 sp or from one host to another within 1 genus; i.e. polyvalent.
    Keywords: Biology ; Ecology ; Environment ; Bacteria ; Fungi ; Microbiological culture ; Viruses ; Actinomycetes ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5208 | 1256 | 2011-09-29 15:16:34 | 5208 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: This project investigated the production of nitrate (nitrification) by bacteria in lakes. The work was undertaken as nitrification is a key process in the nitrogen cycle and previous estimates of rates of nitrification were unreliable. When different methods were used to estimate rates of nitrification within sediment deposits different results were obtained. Investigation' of specific aspects of these methodologies has allowed some rationalization of these observations and also enabled comparisons of previously published data which, beforehand, was not possible. However, it was not clear which methods gave the most reliable rate estimates. Calculation of a nitrate budget for Grasmere lake indicated that the use of methods which involved the mixing of surface sediments (and therefore disrupted preformed nutrient gradients) overestimated the rate of nitrification. The study concludes that slight changes in the method used to prepare sediment slurries can result in large changes, in the measured nitrifying activity. This makes comparisons between studies, using different methods, extremely difficult. Methods to study sediment nitrification processes which do not disrupt preformed substrate gradients within the sediment provide the most reliable rate estimates.
    Keywords: Ecology ; Limnology ; Bacteria ; Nitrification ; Freshwater lakes ; Sediment samples ; Slurries ; Seasonal variations ; Methodology ; England ; Grasmere Lake
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 47
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5239 | 3949 | 2011-09-29 15:13:47 | 5239 | Freshwater Biological Association
    Publication Date: 2021-06-24
    Description: This review discusses the processes involved in the decomposition of organic carbon derived initially from structural components of algae and other primary producers. It describes how groups of bacteria interact in time and space in a eutrophic lake. The relative importance of anaerobic and aerobic processes are discussed. The bulk of decomposition occurs within the sediment. The role of bacteria in the nitrogen cycle and the iron cycle, and in sulphate reduction and methanogenesis as the terminal metabolism of organic carbon are described.
    Keywords: Biology ; Chemistry ; Anaerobic bacteria ; Bacteria ; Biodegradation ; Carbon cycle ; Eutrophic lakes ; Fresh water ; Geochemical cycle ; Iron ; Manganese ; Nitrates ; Nitrogen cycle ; Organic carbon ; Oxygen consumption ; Partical size ; Sedimentation ; Sulphates ; Sulphur ; Annual report
    Repository Name: AquaDocs
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5319 | 1256 | 2011-09-29 15:05:39 | 5319 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Tap water is not sterile; it contains organisms which grow in water distribution systems or inside taps and their fittings. The absence of known pathogenic bacteria is assured by the absence of the indicator organisms but concerns have been raised in the past few years that drinking water fulfilling the standards laid down in the EC Directive ECC 80/778 may still cause disease. These concerns have arisen from several sources: the fact that a cause has been identified in only half of all suspected waterborne outbreaks of disease; reports have suggested that heterotrophic bacteria possessing single pathogenic mechanisms such as haemolysin may cause disease; reports of heterotrophic organisms causing water contact diseases in hospitals. These concerns led to a reappraisal of the pathogenic potential of heteretrophic bacteria, by carrying out an extensive literature search and review commissioned by the UK Water Research Company. This research identified many papers showing an association between drinking water and heterotrophic bacteria but only very few reports of suspected waterborne disease associated with the heterotrophs. The organisms demonstrating potential to cause disease were species of Aeromonas and Yersinia, but typing of organisms identified in patients and isolated from the water revealed very few similarities. The potential of Aeromonas and Yersinia to cause waterborne disease is thought to be very low and the Communicable Disease Surveillance Centre database of laboratory infections due to these two genera of organisms was analysed to produce population-related incidences for each health region in England and Wales. Additionally a laboratory questionnaire revealed different levels of ascertainment of these two organisms in different laboratories of the Public Health Laboratory Service.
    Keywords: Ecology ; Health ; Limnology ; Public health ; Microbial contamination ; Water pollution treatment ; Bacteria ; Bacterial diseases ; Water supply ; Water policy ; Heterotrophic organisms
    Repository Name: AquaDocs
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/5047 | 1256 | 2011-09-29 15:28:19 | 5047 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: Laboratory research was done in order to study the feeding of larval Cricotopus silvestris F. in relation to characters of structure of oral apparatus. Results of the experiments are summarised and the oral apparatus morhologically described.
    Description: Translated from Russian into English
    Keywords: Biology ; Limnology ; Freshwater lakes ; Zooplankton ; Nutrition ; Carbon 14 ; Bacteria ; Algae ; Russia ; Asplanchna priodonta ; Asplanchna herricki
    Repository Name: AquaDocs
    Type: monograph
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    Freshwater Biological Association | Windermere, UK
    In:  http://aquaticcommons.org/id/eprint/5064 | 1256 | 2011-09-29 15:30:02 | 5064 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: The morphology, increase and systematica of Sphaerotilus natans is studied and culture methods examined.
    Description: Translated from German into English
    Keywords: Biology ; Limnology ; Bacteria ; Bacteriology ; Identification ; Experimental culture ; Laboratory culture ; Methodology
    Repository Name: AquaDocs
    Type: monograph
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5114 | 3949 | 2011-09-29 15:21:32 | 5114 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article looking at the numerical distribution of bacteria in lakes, the types most commonly present and the nitrogen-cycle, in Lake Windermere. The methodology is explained, including the sampling frequency and depths, and bacteria culturing techniques. Water bodies other than Lake Windermere were also sampled and these are detailed, including a water reservoir. A summary of the work into horizontal of bacteria is given, including a table showing the number of bacteria per millilitre at different distances from inflow into Windermere. A summary of the work into vertical distribution is also given, including two figures, one showing seasonal variation during 1938-9 in numbers of bacteria at different depths in Winderemere, and the other showing the relationship between the numbers of bacteria at 10 metres depth in Windermere and the rainfull during the previous 7 days. A summary of the types of bacteria found, as well as work on the nitrogen cycle in Esthwaite Water, Lake Windermere and Blelham Tarn are given.
    Keywords: Biology ; Chemistry ; Limnology ; Nitrogen cycle ; Bacteria ; Freshwater ecology ; Limnology ; Seasonal variations ; Water column ; Water reservoirs ; Annual reports ; England ; Lake District
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    Format: application/pdf
    Format: 51-57
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5168 | 3949 | 2011-09-29 15:18:43 | 5168 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: Obtaining a reliable estimate of the bacterial population is one of the main problems facing the bacterial ecologist. The author discusses the various methods available and concludes that the observed variability in bacterial populations depends on the sampling interval used.
    Keywords: Biology ; Ecology ; Bacteria ; Biomass ; Population characteristics ; Population number ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5184 | 3949 | 2011-09-29 15:17:22 | 5184 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Three different methods for determining bacterial growth rate in rivers are described. Two of the methods are for bacteria in suspension: a recirculating experimental channel method and a radioactive tracer technique using super(35)SO sub(4). The third method is for bacteria attached to surfaces and specifically considers the surface of the common duckweed Lemna minor).
    Keywords: Biology ; Ecology ; Bacteria ; Growth ; Nannoplankton ; Rivers ; Lemna minor ; England ; Dorset ; River Frome ; Annual report
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  • 38
    Publication Date: 2022-05-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gosselin, K. M., Nelson, R. K., Spivak, A. C., Sylva, S. P., Van Mooy, B. A. S., Aeppli, C., Sharpless, C. M., O’Neil, G. W., Arrington, E. C., Reddy, C. M., & Valentine, D. L. Production of two highly abundant 2-methyl-branched fatty acids by blooms of the globally significant marine cyanobacteria Trichodesmium erythraeum. ACS Omega, 6(35), (2021): 22803–22810, https://doi.org/10.1021/acsomega.1c03196.
    Description: The bloom-forming cyanobacteria Trichodesmium contribute up to 30% to the total fixed nitrogen in the global oceans and thereby drive substantial productivity. On an expedition in the Gulf of Mexico, we observed and sampled surface slicks, some of which included dense blooms of Trichodesmium erythraeum. These bloom samples contained abundant and atypical free fatty acids, identified here as 2-methyldecanoic acid and 2-methyldodecanoic acid. The high abundance and unusual branching pattern of these compounds suggest that they may play a specific role in this globally important organism.
    Description: This work was funded with grants from the National Science Foundation grants OCE-1333148, OCE-1333162, and OCE-1756254 and the Woods Hole Oceanographic Institution (IR&D). GCxGC analysis made possible by WHOI’s Investment in Science Fund.
    Keywords: Lipids ; Alkyls ; Bacteria ; Genetics ; Chromatography
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 39
    Publication Date: 2017-04-04
    Description: Balanced information and education are fundamental prerequisites for risk prevention and preparedness. Among others, children embody our best chance to implant appropriate behaviors that will be recalled during hazardous situations and to involve adults according to a knowledge chain reaction. In this work, scientists challenge their communication skills to built a set of hands-on and learn-by-play based laboratory activities, for primary and secondary schools, addressing three major issues: (1) the location of earthquakes and volcanoes on Earth; (2) earthquakes and eruptions mechanisms; (3) earthquakes unpredictability. Students are asked to place volcanoes and earthquakes epicenters (issue 1) on a wooden plate puzzle according to Plate dynamics. To addresses eruption mechanisms (issue 2) and related hazard, we use backing soda forced blowing out from a volcano vent and suggest that a pyroclastic flow is fast, it can spread over a large area and raise high up to the stratosphere. Earthquake mechanisms (issue 2) are discussed describing the energy buildup, release, and transfer, using a wooden sticks bendand- break analogy. The display of acoustic waves caused by the breakage in different situations allows understanding of both the rupture energy and the wave attenuation. Earthquakes occurrence (issue 3) is addressed using steadily pulled blocks sliding on a frictional surface, where pins simulate asperities. These activities were tested, involving thousands of students. Discussions with students and teachers and the analysis of the answers to specific questionnaires gave us confidence that we proposed proper tools to raise risk awareness
    Description: Published
    Description: 89-93
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: restricted
    Keywords: Seismic and volcanic hazards, Outreach, Education ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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    Publication Date: 2020-02-24
    Description: In 2011 a research project on volcanic risk assessment at La Réunion Island (Project Aléa, Institute de Physique du Globe de Paris, France) was conducted in order to determine more efficient strategies to manage future volcanic crises. The project included the evaluation of volcanic scenarios through field and historical data analysis, as well as a survey on volcanic risk perception in resident population. A clear scientific information and an effective communication with public play a crucial role in risk mitigation strategies. In particular, the evaluation of the public perception during both volcanic crises and dormant periods is an important element in developing actions focused on specific social and cultural contexts. A questionnaire was developed based on the ones used in similar researches conducted on Italian active volcanoes. Items were designed to measure variables connected with personal perception of hazard and risk, trust in mitigation actions and in information received about these aspects. In addition, specific items related to the peculiarities of La Réunion Island environment were included. A total of 2,000 questionnaires were distributed taking into account factors such as the proximity to the volcano and the involvement of communities in recent volcanic emergencies. Main results coming out from this survey, if on the one hand show an adequate residents’ perception of natural hazards, on the other hand highlight their poor knowledge of the island’ active volcano, a similar lacking knowledge of emergency plan for volcanic crises, but also a high confidence in scientists to provide accurate and reliable information on volcanic risk and hazards in contrast with Local Authorities. Remarkable findings of this study assess some key elements that should be considered by the institutions in charge for defining policies aimed to volcanic risk mitigation and management of future volcanic crises.
    Description: Unpublished
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: reserved
    Keywords: risk perception, volcanic hazards ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2017-04-04
    Description: This book is one out of 8 IAEG XII Congress volumes, and deals with education and the professional ethics, which scientists, regulators, and practitioners of engineering geology inevitably have to face through the purposes, methods, limitations, and findings of their works. This volume presents contributions on the professional responsibilities of engineering geologists; the interaction of engineering geologists with other professionals; recognition of the engineering geological profession and its particular contribution to society, culture, and economy; and implications for the education of engineering geologists at tertiary level and in further education schemes. Issues treated in this volume are: the position of engineering geology within the geo-engineering profession; professional ethics and communication; resource use and re-use; managing risk in a litigious world; engineering and geological responsibility; and engineering geology at tertiary level. The Engineering Geology for Society and Territory volumes of the IAEG XII Congress held in Torino from September 15-19, 2014, analyze the dynamic role of engineering geology in our changing world and build on the four main themes of the congress: Environment, processes, issues, and approaches.
    Description: Published
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 5A. Energia e georisorse
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: open
    Keywords: Geoethics ; Geoeducation ; Professional Ethics ; Engineering Geology ; Communication ; Society ; Risks management ; Georesources ; Geological responsibility ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Publication Date: 2017-04-04
    Description: The defence against natural hazards involves many actors with different roles: geoscientists, decision makers, local authorities, mass media, citizens. A proper management of georisks requires that each role is well-defined and governed by shared operational protocols, especially during the emergency phase, so that overlapping and misunderstanding don’t jeopardize population safety and economic activities. To achieve good results in this direction, it is necessary to undertake a careful evaluation of the limits and expectations of each component of society and the respect of legitimate aspirations and prerogatives. An effective defence system against natural hazards should be planned rationally and based on scientific data, in order to avoid alarmism among citizens, misleading sensationalism by media, careless decisions by politicians, as well as approximation in managing different phases of the risk cycle. Taking into consideration geoethical aspects related to natural hazards can be helpful to make geoscientists aware of their responsibilities towards society and to clarify the role they can play in the interaction with other actors, aiming at more efficacious actions for georisk mitigation.
    Description: Published
    Description: 59-62
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 4V. Vulcani e ambiente
    Description: 4A. Clima e Oceani
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: restricted
    Keywords: Geoethics ; Natural hazards ; Risks ; Society ; Responsibility ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 43
    Publication Date: 2020-02-24
    Description: The communication process between the geoscientists and native communities in risk areas can significantly affect disaster prevention and land use planning. In Peru, the problem of disaster prevention is a fundamental policy due to unfamiliarity and deficiency of the associate information on the population. It is possible that talk of disaster prevention it will be an unlikely ideal in a country where most towns have settled on unplanned projects by the constant change and the lack of interest from the authorities in such topics. However, it is anachronistic that the rural communities and towns continue to live without a plan to enable them to improve their quality of life. The correct use of geoscience information in the mass media can help in this work. The characteristics of the enterprise in Peru require more training by professionals in the geosciences and support communication specialists. In this paper, we analyze the problem of communication for disaster prevention in Peru, with the aim of contributing to the articulation of a disaster prevention strategy.
    Description: Published
    Description: 81-83
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 4V. Vulcani e ambiente
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: reserved
    Keywords: Communication process ; Disaster prevention ; Risk management ; Peru ; Geoethics ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 44
    Publication Date: 2020-10-26
    Description: One of the main objectives of the ITACA (ITalian ACcelerometric Archive) strong motion database, promoted by the Italian Department of Civil Protection, was to improve the characterization of the recording sites from a geological and geophysical point of view and to provide their seismic classification according to the seismic norms pertinent to Italy, namely the Eurocode 8 and the National Technical Norms for Constructions. A standard format to summarize the available information for the recording stations was first produced, in terms of a technical report dynamically linked to the database, i.e., some of the relevant information is automatically updated when the corresponding fields of the database are modified. Then, an important activity of collection, qualification and synthesis of available data was carried out, especially for stations that recorded the strongest earthquakes in Italy in the last 40 years, and for which a relevant number of studies have been published. In spite of this activity, among the more than 700 strong motion stations present in the ITACA database, only a limited number of them could be characterized by quantitative information on subsurface soil properties. For this reason, a dual seismic site classification criterion was implemented, either based on the standard Vs,30 scheme, or, in the absence of such information, based on an expert opinion supported by shallow geology maps, mostly at 1:100,000 scale, and when available on the H/V ratios calculated on recordings. Owing to the relevance in the Italian geographic and morphological context, a special care was also given to the topographic classification of stations, based on suitable criteria developed within a GIS environment.
    Description: Published
    Description: 1779-1796
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: ITACA database ; Strong motion station ; General characterization ; Site classification ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
    facet.materialart.
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    Springer
    Publication Date: 2017-04-04
    Description: Previous research works proved the existence of a synchronization between speech and holds in adults and in 9 year old children with a rich linguistic vocabulary and advanced language skills. When and how does this synchrony develop during child language acquisition? Could it be observed also in children younger than 9? The present work aims to answer the above questions reporting on the analysis of narrations produced by three different age groups of Italian children (9, 5 and 3 year olds). Measurements are provided on the amount of synchronization between speech pauses and holds in the three different groups, as a function of the duration of the narrations. The results show that, as far as the reported data concerns, in children, as in adults, holds and speech pauses are to a certain extent synchronized and play similar functions, suggesting that they may be considered as a multi-determined phenomenon exploited by the speaker under the guidance of a unified planning process to satisfy a communicative intention. In addition, considering the role that speech pauses play in communication, we speculate on the possibility that holds may serve to similar purposes supporting the hypothesis that gestures as speech are an expressive resource that can take on different functions depending on the communicative demand. While speech pauses are likely to play the role of signalling mental activation processes aimed at replacing the “old spoken content” of the communicative plan with a new one, holds may signal mental activation processes aimed at replacing the “old visible bodily action” with new ones reflecting the representational and/or propositional contribution of gestures to the new communicative plan.
    Description: Published
    Description: 252-272
    Description: 5.9. Formazione e informazione
    Description: restricted
    Keywords: Speech pauses, holds, synchrony, child narrations ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 46
    facet.materialart.
    Unknown
    Istituto Nazionale di Geofisica e Vulcanologia
    Publication Date: 2017-04-04
    Description: This is the first volume of an international scientific journal that is dedicated to issues of geoethics and geological culture. Its goal is to inform the Italian and international scientific communities about what emerged at the GeoItalia 2011 conference, attended by not only Italian geoscientists. At this conference, the geoscientists questioned their role in society and the responsibilities that they have to assume as scholars of the planet Earth and experts of the territory. They highlighted the need for rediscovery of the cultural values of geology as a science that can contribute to the construction of correct social knowledge, and the need to be aware that geoethics cannot exist without a real awareness among geoscientists of the cultural value of the Earth sciences.
    Description: Published
    Description: 331
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: open
    Keywords: Geoethics ; Geoetica ; Geological Culture ; Earth Sciences ; Philosophy ; Education ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
    facet.materialart.
    Unknown
    Istituto Nazionale di Geofisica e Vulcanologia
    Publication Date: 2017-04-04
    Description: Prof. Giulio Giorello is amongst the most prominent philosophers of science in Italy and in the world. He is currently Professor of the Philosophy of Science at the University of Milan, Director of the Series ‘Science and Ideas’ (Raffaele Cortina Books Editor), and Literary Journalist of the cultural pages of the Corriere della Sera, one of the most important of the Italian newspapers. In this keynote presentation, in interview form, he talks about the value that the Earth sciences have had through history, framing this group of disciplines in ethical and epistemological terms, and highlighting some important elements that have to be considered in geological activities.
    Description: Published
    Description: 343-346
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: open
    Keywords: Geoethics ; Geological Culture ; Geoetica ; Giulio Giorello ; Earth Sciences ; Interview ; Philosophy ; Epistemology ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
    facet.materialart.
    Unknown
    Istituto Nazionale di Geofisica e Vulcanologia
    Publication Date: 2017-04-04
    Description: The international debate in the field of geoethics focuses on some of the most important environmental emergencies, while highlighting the great responsibilities of geoscientists, whatever field they work in, and the important social, cultural and economic repercussions that their choices can have on society. The GeoItalia 2009 and 2011 conferences that were held in Rimini and Turin, respectively, and were organized by the Italian Federation of Earth Science, were two important moments for the promotion of geoethics in Italy. They were devoted to the highlighting of how, and with what tools and contents, can the geosciences contribute to the cultural renewal of society. They also covered the active roles of geoscientists in the dissemination of scientific information, contributing in this way to the correct construction of social knowledge. Geology is culture, and as such it can help to dispel misconceptions and cultural stereotypes that concern natural phenomena, disasters, resources, and land management. Geological culture consists of methods, goals, values, history, ways of thinking about nature, and specific sensitivity for approaching problems and their solutions. So geology has to fix referenced values, as indispensable prerequisites for geoethics. Together, geological culture and geoethics can strengthen the bond that joins people to their territory, and can help to find solutions and answers to some important challenges in the coming years regarding natural risks, resources, and climate change. Starting from these considerations, we stress the importance of establishing an ethical criterion for Earth scientists, to focus attention on the issue of the responsibility of geoscientists, and the need to more clearly define their scientific identity and the value of their specificities.
    Description: Published
    Description: 335-341
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: open
    Keywords: Geoethics ; Education ; History of science ; Public issues ; General (Philosophy of Earth sciences) ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
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  • 49
    facet.materialart.
    Unknown
    Istituto Nazionale di Geofisica e Vulcanologia
    Publication Date: 2017-04-04
    Description: Franco Ferrarotti, Professor emeritus at ‘La Sapienza’ University of Rome; since winning the first Chair in this discipline in Italy in 1961, he has been considered the Father of Italian Sociology. An independent Member of Italian Parliament in the third government (1958-1963), a member of the New York Academy of Sciences, and a ‘visiting Professor’ at many universities in Europe, North America, Russia, Japan and Latin America. Franco Ferrarotti has taught and still teaches in Europe and America, and he has received many awards throughout his career. In this interview, he talks about the social aspects and consequences of Earth sciences studies.
    Description: Published
    Description: 347-348
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: open
    Keywords: Geoethics ; Geological Culture ; Geoetica ; Social aspects ; Geologists activity ; Scientific information ; Society ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 50
    facet.materialart.
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    Istituto Nazionale di Geofisica e Vulcanologia
    Publication Date: 2017-04-04
    Description: We argue here that the introduction of an ethical code of conduct that follows the example of the Hippocratic Oath of physicians will help geologists to acquire binding awareness of their professional and social responsibilities. The ethical behavior and obligations of modern geologists involve, but are not limited to, the following issues: correct land/ environment use and management; respect of truth and science; and protection of the Earth systems, on both the local and global scales, and therefore, of our well-being. We believe that for geoligists, the explicit acceptance of an ethical code will help to promote: (i) an awareness of their social role, expertise and sense of belonging to a professional community; (ii) an understanding of the expectations of citizens and society; and (iii) cultural growth, with better use of research and implementation of scientific and professional skills. All this should enhance the public recognition of the social mission of geologists, which is essential for the well-being of society. Therefore, we suggest that like in the majority of medical schools, ethical training should be a part of the university curriculum for students in geology.
    Description: Published
    Description: 365-369
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: open
    Keywords: Geoethics ; Geological Culture ; Geoetica ; Hippocratic Oath ; Geologists ; Social responsibility ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
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  • 51
    Publication Date: 2022-05-26
    Description: © The Authors 2009. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Functional & Integrative Genomics 10 (2010): 97-110, doi:10.1007/s10142-009-0142-y.
    Description: Bacteria of the genus Shewanella can thrive in different environments and demonstrate significant variability in their metabolic and ecophysiological capabilities including cold and salt tolerance. Genomic characteristics underlying this variability across species are largely unknown. In this study, we address the problem by a comparison of the physiological, metabolic, and genomic characteristics of 19 sequenced Shewanella species. We have employed two novel approaches based on association of a phenotypic trait with the number of the trait-specific protein families (Pfam domains) and on the conservation of synteny (order in the genome) of the trait-related genes. Our first approach is top-down and involves experimental evaluation and quantification of the species’ cold tolerance followed by identification of the correlated Pfam domains and genes with a conserved synteny. The second, a bottom-up approach, predicts novel phenotypes of the species by calculating profiles of each Pfam domain among their genomes and following pair-wise correlation of the profiles and their network clustering. Using the first approach, we find a link between cold and salt tolerance of the species and the presence in the genome of a Na+/H+ antiporter gene cluster. Other cold-tolerance-related genes include peptidases, chemotaxis sensory transducer proteins, a cysteine exporter, and helicases. Using the bottom-up approach, we found several novel phenotypes in the newly sequenced Shewanella species, including degradation of aromatic compounds by an aerobic hybrid pathway in Shewanella woodyi, degradation of ethanolamine by Shewanella benthica, and propanediol degradation by Shewanella putrefaciens CN32 and Shewanella sp. W3-18-1.
    Description: This research was supported by the U.S. Department of Energy (DOE) Office of Biological and Environmental Research under the Genomics: GTL Program via the Shewanella Federation consortium.
    Keywords: Phenotypic trait ; Bacteria ; Molecular mechanisms of cold tolerance ; Shewanella ; Protein families
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 52
    Publication Date: 2017-04-04
    Description: Red Pompeian paintings, very famous for their deep intensity, are currently suffering from darkening. The origins of this darkening degradation are not clearly identified yet and remain a major issue for curators. In the specific case of cinnabar (HgS)-based red pigment, a photoinduced conversion into black metacinnabar is usually suspected. This work is focused on the blackening of red cinnabar paintings coated on a sparry calcite mortar. Different samples exhibiting different levels of degradation were selected upon visual observations and analyzed by synchrotron-based microanalytical techniques. Atomic and molecular compositions of the different debased regions revealed two possible degradation mechanisms. On one hand, micro X-ray fluorescence elemental maps show peculiar distributions of chlorine and sulfur. On the other hand, X-ray absorption spectroscopy performed at both Cl and S K-edges confirms the presence of characteristic degradation products: (i) Hg- Cl compounds (e.g., corderoite, calomel, and terlinguaite), which may result from the reaction with exogenous NaCl, in gray areas; (ii) gypsum, produced by the calcite sulfation, in black coatings. Metacinnabar is never detected. Finally, a cross section was analyzed to map the in-depth alteration gradient. Reduced and oxidized sulfur distributions reveal that the sulfated black coating consists of a 5-ím-thick layer covering intact cinnabar.
    Description: Published
    Description: 7484-7492
    Description: reserved
    Keywords: Microspectroscopy Analysis ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
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  • 53
    ISSN: 1433-4909
    Keywords: Key words Extreme thermophile ; Thermosipho ; Thermotogales ; Deep-sea hydrothermal vent ; Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A novel barophilic, extremely thermophilic bacterium was isolated from a deep-sea hydrothermal vent chimney at the Iheya Basin, in the Okinawa area, Japan. The cells were found to be rod shaped and surrounded by a sheath-like outer structure; the organism did not possess flagella and was not motile. Growth was observed between 45° and 80°C (optimum, 72°C, 45 min doubling time), pH 5.3 and 9.3 (optimum, pH 7.2–7.6), 6.6 and 79 g/l sea salts (optimum, 40 g/l), and 0.1 and 60 MPa (optimum, 20 MPa). Strain IHB1 was found to be a strictly anaerobic chemoorganotroph capable of utilizing yeast extract and proteinaceous substrates such as peptone and tryptone. Elemental sulfur or thiosulfate acted as electron acceptors improving growth. The isolate was able to utilize casein as a sole carbon and energy source in the presence of thiosulfate. The G + C content of the genomic DNA was 31.4 mol%. Phylogenetic analysis based on 16S rDNA sequences and DNA–DNA hybridization analysis indicated that the isolate is closely related to Thermosipho africanus; however, it represents a species distinct from the previously described members of the genus Thermosipho. On the basis of the physiological and molecular properties, we propose that the new isolate represents a new species, which we name Thermosipho japonicus sp. nov. (type strain: IHB1; JCM10495).
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  • 54
    ISSN: 1432-0789
    Keywords: Keywords Aggregate stability ; Bacteria ; Burnt soil ; Compost ; Fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The restoration of soil microbial activities is a basic step in the reclamation of burnt soils. For this reason, the ability of municipal solid waste compost to accelerate the re-establishment of bacterial and fungal populations, as well as to re-establish physical properties in a burnt soil, was evaluated in a field experiment. Four treatments were performed by adding different doses of compost (0, 0.5, 1 and 2 kg compost m–2 soil) to a burnt Calcic Rodoxeralf soil, and the changes in microbial populations, salt content, aggregate stability and bulk density were evaluated for 1 year. Initially, the addition of compost had a negative effect on soil microbial populations, but 3 months after compost addition, the number of viable fungal propagules increased in all the amended soils. This positive effect lasted until the end of the experiment. From 30 days onwards, all the amended soils showed a greater total number of bacterial cell forming units than the unamended burnt soil. Organic amendment increased the percentage of 2- to 4-mm aggregates, although the effect on the stability of the 0.2- to 2-mm aggregates and on bulk density was less noticeable.
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  • 55
    ISSN: 1432-2021
    Keywords: Key words Cristobalite ; Tridymite ; Phase transformation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Using minimum exposure techniques, it is feasible to perform high resolution electron microscopy on the α-cristobalite phase of (Si0.9 Ge0.1)O2, which is extremely radiation sensitive. Such images reveal atomic scale information of twins and tridymite-like stacking faults on (1 1 1)β planes, as well as of domain boundaries resulting from the β→α transition. Polytype structures are formed in certain cases. Morphological features suggest that the phase transformation cristobalite → tridymite proceeds by means of a zonal dislocation mediated synchro-shear process on (1 1 1)β planes; the geometry of this process is analyzed.
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  • 56
    ISSN: 1432-1017
    Keywords: Key words X-ray crystallography ; Electron microscopy ; Biological databases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Advances in structural biology are opening greater opportunities for understanding biological structures from the cellular to the atomic level. Particularly promising are the links that can be established between the information provided by electron microscopy and the atomic structures derived from X-ray crystallography and nuclear magnetic resonance spectroscopy. Combining such different kinds of structural data can result in novel biological information on the interaction of biomolecules in large supramolecular assemblies. As a consequence, the need to develop new databases in the field of structural biology that allow for an integrated access to data from all the experimental techniques is becoming critical. Pilot studies performed in recent years have already established a solid background as far as the basic information that an integrated macromolecular structure database should contain, as well as the basic principles for integration. These efforts started in the context of the BioImage project, and resulted in a first complete database prototype that provided a versatile platform for the linking of atomic models or X-ray diffraction data with electron microscopy information. Analysis of the requirements needed to combine data at different levels of resolution have resulted in sets of specifications that make possible the integration of all these different types in the context of a web environment. The case of a structural study linking electron microscopy and X-ray data, which is already contained within the BioImage data base and in the Protein Data Bank, is used here to illustrate the current approach, while a general discussion highlights the urgent need for integrated databases.
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  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 27 (2000), S. 480-494 
    ISSN: 1432-2021
    Keywords: Key words Olivine ; Grain boundary ; Partial melt ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The microstructure of olivine-olivine grain boundaries has been studied in experimentally deformed (1200–1227 °C, 300 MPa) partially molten olivine and olivine-orthopyroxene rocks. In-situ melting produced ∼1 vol% melt in all samples studied. Grain boundary analyses were carried out using a number of transmission electron microscopy techniques. The grain boundary chemistry in undeformed olivine-orthopyroxene starting material showed evidence for the presence of an intergranular phase along some, but not all, of the olivine-olivine boundaries. In the deformed samples, ultrathin Si-rich, Al- and Ca-bearing amorphous films have been observed along all investigated olivine-olivine grain boundaries. The chemistry of the grain boundaries, which is considered to be indicative for the presence of a thin film, was measured with energy-dispersive X-ray spectroscopy (EDX) and energy-filtering imaging. The amorphous nature of the films was confirmed with diffuse dark field imaging, Fresnel fringe imaging, and high-resolution electron microscopy. The films range in thickness from 0.6 to 3.0 nm, and EDX analyses show that the presence of Al and Ca is restricted to this ultrathin film along the grain boundaries. Because thin melt films have been observed in all the samples, they are thought to be stable features of the melt microstructure in deformed partially molten rocks. The transition from the occasional presence of films in the undeformed starting material to the general occurrence of the films in deformed materials suggests that deformation promotes the formation and distribution of the films. Alternatively, hot-pressing may be too short for films to develop along all grain boundaries. A difference in creep strength between the studied samples could not be attributed to grain boundary melt films, as these have been found in all deformed samples. However, a weakening effect of grain boundary melt films on olivine rheology could not be ruled out due to the lack of confirmed melt-film free experiments.
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  • 58
    ISSN: 1619-0904
    Keywords: Poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC) ; In vivo biocompatibility ; Artificial endocrine pancreas ; Electron microscopy ; Glucose sensor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Biocompatibility is important to assure a mild body reaction to an implanted device and its long-term stability and functionality. In diabetes research, subcutaneously implanted glucose monitoring systems need biocompatible surfaces for long-term application. The biocompatibility of poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC), a material similar to the phospholipid layer of a cell membrane, was compared in vivo with the biocompatibility of polyurethane (PU), polyvinyl alcohol (PVA), and cuprophane (CUP). Needle-type glucose sensors and hollow-fiber probes used for microdialysis were coated with these four different biomaterials and implanted subcutaneously in 18 rats and 7 healthy volunteers. At set intervals, the implants and, in the case of the rats, also the surrounding tissue were removed and characterized by light and electron microscopy. MPC-coated sensors and hollow-fiber probes showed smooth and thin deposits in flat layers, whereas the surface deposits on PU- and PVA-coated sensors and those on CUP hollow-fiber probes appeared as rough, irregular, and dense attachments of aggregated cells and protein. This study confirmed results from earlier in vitro tests by showing the biocompatibility and reliability of MPC. Even though the amount of protein and cells attached to the MPC surface was not as low as expected from in vitro experiments, the biocompatibility and long-term stability of the implanted devices were superior to those of PU, PVA, and CUP.
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  • 59
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Photoreceptor ; Visual membrane ; Photic radiation damage ; Retina ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Visual membranes of the crayfish eye either belong to the small, distally placed rhabdomere of retinula cell R8 or are part of the much more voluminous proximal rhabdom, made up of rhabdomeres belonging to cells R1–R7. Under various conditions of environmental stress (e.g., prolonged darkness, elevated temperature, bright light with and without a concomitant rise in temperature, flickering lights) the visual membranes of R8 prove far more resistant to structural damage than those of R1–R7. Membrane damage is known to occur when dormant lipoxygenases become activated, for example through heat. Since R8 is the only type of visual cell in the crayfish retina that does not contain grains of screening pigment, the view that screening-pigment granules could “aggravate” or even “trigger” membrane damage in times of stress is strengthened. Functionally, R8's strong resistance to physical damage when exposed to flickering lights points to a role of the distal rhabdom in the movement detection system of the crayfish eye.
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  • 60
    Electronic Resource
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    Springer
    Antonie van Leeuwenhoek 77 (2000), S. 117-133 
    ISSN: 1572-9699
    Keywords: Archaea ; Bacteria ; hydrothermal vents ; in situ hybridization ; molecular ecology ; probes ; 16S rRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The study of the structure and diversity of hydrothermal vent microbial communities has long been restricted to the morphological description of microorganisms and the use of enrichment culture-based techniques. Until recently the identification of the culturable fraction required the isolation of pure cultures followed by testing for multiple physiological and biochemical traits. However, peculiar inhabitants of the hydrothermal ecosystem such as the invertebrate endosymbionts and the dense microbial mat filaments have eluded laboratory cultivation. Substantial progress has been achieved in recent years in techniques for the identification of microorganisms in natural environments. Application of molecular approaches has revealed the existence of unique and previously unrecognized microorganisms. These have provided fresh insight into the ecology, diversity and evolution of mesophilic and thermophilic microbial communities from the deep-sea hydrothermal ecosystem. This review reports the main discoveries made through the introduction of these powerful techniques in the study of deep-sea hydrothermal vent microbiology.
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  • 61
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    Journal of comparative physiology 170 (2000), S. 531-535 
    ISSN: 1432-136X
    Keywords: Key words Large intestine ; Furrow of proximal colon ; Digesta ; Bacteria ; Soft and hard feces ; Nutrias ; Myocastor coypus ; AbbreviationsN nitrogen ; TAA total amino acids ; DAP diaminopimelic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The bacterial level of soft feces is higher than that of hard feces in nutrias. This suggests the heterogeneity of bacterial density in the large intestine. To show the heterogeneity of bacteria in the contents of the large intestine in nutrias, we divided the contents of the large intestine into 12 regions, then measured the nitrogen (N), total amino acids (TAA) and diaminopimelic acid (DAP), a bacterial marker, of these regions. Levels of N, TAA and DAP varied along the cross section of the proximal colon. The greater curvature of the main lumen and furrow had higher N, TAA and DAP concentrations than the lesser curvature. We also examined the involvement of the furrow in producing two types of feces differing in bacterial nitrogen content by surgically preventing the flow of the furrow contents. We compared the concentrations of N, TAA and DAP between soft and hard feces among operated, sham-operated and intact animals. Surgical closure of the furrow abolished the difference in levels of N, TAA and DAP between soft and hard feces, suggesting that the furrow of the proximal colon is responsible for making the bacterial density higher in soft feces than in hard feces.
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  • 62
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    World journal of microbiology and biotechnology 16 (2000), S. 495-497 
    ISSN: 1573-0972
    Keywords: Bacteria ; biodegradation ; 2,4-D ; soil microcosm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Bacterial isolates (NJ 10 and NJ 15) capable of degrading the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) were isolated from agricultural soil by enrichment culture technique. The isolates exhibited substantial growth in mineral salt medium supplemented with 0.1–0.5% of 2,4-D as a sole source of carbon and energy. Based on their morphological, cultural and biochemical characteristics, the isolates NJ 10 and NJ 15 have been identified as Pseudomonas species and Pseudomonas aeruginosa, respectively. Biodegradation studies in a soil microcosm enriched with pure cultures of the isolates demonstrated a time-dependent disappearance of 2,4-D from the 100 mg/kg herbicide-amended soil. The HPLC data analysis revealed 96.6 and 99.8% degradation in the soil inoculated with the pure cultures of isolates NJ 10 and NJ 15, respectively with in 20 days of incubation at 30 °C. Both the isolates showed significant solubilization of inorganic phosphate [Ca3(PO4)2] on the specific Pikovskaya's medium.
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  • 63
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    World journal of microbiology and biotechnology 16 (2000), S. 115-134 
    ISSN: 1573-0972
    Keywords: Bacteria ; biocontrol ; biological control ; compost ; disease ; fungi ; microbiology ; pathogen ; suppression ; turf ; turfgrass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The relationships among the chemical, physical and biological aspects of compost and their role in suppression of turfgrass pathogens are reviewed. The composting process, mediated by microbial activity, is affected by physical and chemical characteristics which include temperature, aeration, moisture content, C:N ratio and pH. In the absence of parameter restrictions, the microbial community follows a predictable successional pattern resulting in the re-colonization of compost with metabolically active mesophilic populations that can be suppressive towards plant pathogens. Although mechanisms of suppression are not fully understood, those postulated include physiochemical and biological characteristics. The physiochemical characteristics of composts can alter suppressive properties through direct effects on pathogens and antagonistic microorganisms, or indirect effects on host systems through the supply of nutrients, improvement of soil structure, porosity and water retention capabilities, along with other factors. Biological characteristics centre on microbial community involvement in suppressive mechanisms, which can include one or a combination of competition for nutrients, antibiosis, lytic and other extracellular enzyme production, parasitism, predation and host-mediated induction of resistance. As a result of the potential benefits of compost, there is considerable interest in determining the capacity for composts to suppress turfgrass pathogens. Although the exact mechanisms of suppression are largely unknown, there appear to be several factors that play an integrated role. The use of composts that successfully suppress turfgrass diseases will permit a reduction in the use of chemical controls, and slow the development of fungicide resistance.
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  • 64
    ISSN: 1432-0789
    Keywords: Key words Grasslands ; Management ; Microbial biomass ; Bacteria ; Fungi ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  There is much interest in the development of agricultural land management strategies aimed at enhancing reliance on ecosystem self-regulation rather than on artificial inputs such as fertilisers and pesticides. This study tested the usefulness of measures of soil microbial biomass and fungal:bacterial biomass ratios as indicators of effective conversion from an intensive grassland system, reliant mainly on fertilisers for crop nutrition, to a low-input system reliant mainly on self-regulation through soil biological pathways of nutrient turnover. Analysis of soils from a wide range of meadow grassland sites in northern England, along a gradient of long-term management intensity, showed that fungal:bacterial biomass ratios (measured by phospholipid fatty acid analysis; PLFA) were consistently and significantly higher in the unfertilised than the fertilised grasslands. There was also some evidence that microbial biomass, measured by chloroform fumigation and total PLFA, was higher in the unfertilised than in the fertilised grasslands. It was also found that levels of inorganic nitrogen (N), in particular nitrate-N, were significantly higher in the fertilised than in the unfertilised grasslands. However, microbial activity, measured as basal respiration, did not differ between the sites. A field manipulation trial was conducted to determine whether the reinstatement of traditional management on an improved mesotrophic grassland, for 6 years, resulted in similar changes in the soil microbial community. It was found that neither the cessation of fertiliser applications nor changes in cutting and grazing management significantly affected soil microbial biomass or the fungal:bacterial biomass ratio. It is suggested that the lack of effects on the soil microbial community may be related to high residual fertility caused by retention of fertiliser N in the soil. On the basis of these results it is recommended that following the reinstatement of low-input management, the measurement of a significant increase in the soil fungal:bacterial biomass ratio, and perhaps total microbial biomass, may be an indicator of successful conversion to a grassland system reliant of self-regulation.
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  • 65
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    Biology and fertility of soils 29 (1999), S. 170-177 
    ISSN: 1432-0789
    Keywords: Key words Chitin degradation ; Succession ; Fungi ; Bacteria ; Actinomycetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The dynamics of culturable chitin-degrading microorganisms were studied during a 16-week incubation of chitin-amended coastal dune soils that differed in acidity. Soil samples were incubated at normal (5% w/w) and high (15% w/w) moisture levels. More than half of the added chitin was decomposed within 4 weeks of incubation in most soils. This rapid degradation was most likely due to fast-growing chitinolytic fungi (mainly Mortierella spp. and Fusarium spp.) at both moisture levels, as dense hyphal networks of these fungi were observed during the first 4 weeks of incubation. Chitin N mineralization was inhibited by cycloheximide, and fast-growing fungal isolates were capable of rapid chitin decomposition in sterile sand, further suggesting that these fungi play an important role in initial chitin degradation. The strong increase in fast-growing fungi in chitin-amended dune soils was only detected by direct observation. Plate counts and microscopic quantification of stained hyphae failed to reveal such an increase. During the first part of the incubation, numbers of unicellular chitinolytic bacteria also increased, but their contribution to chitin degradation was indicated to be of minor importance. During prolonged incubation, colony forming units (CFU) of chitinolytic streptomycetes and/or slow-growing fungi increased strongly in several soils, especially at the 5% moisture level. Hence, the general trend observed was a succession from fast-growing fungi and unicellular bacteria to actinomycetes and slow-growing fungi. Yet, the composition of chitinolytic CFU over time differed strongly between chitin-amended dune soils, and also between the two moisture levels. These differences could not be attributed to pH, organic matter or initial microbial composition. The possible consequence of such unpredictable variation in microbial community composition for the use of chitin-amendments as a biocontrol measure is discussed.
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  • 66
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    Biology and fertility of soils 28 (1999), S. 431-435 
    ISSN: 1432-0789
    Keywords: Key words Actinomycetes ; Bacteria ; Cynodon spp. ; Fungi ; Turfgrass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Four natural organic fertilizers, alone or in combination with the synthetic organic fertilizer isobutylidene diurea (IBDU), were compared with IBDU alone for their effect on soil/root microbial populations associated with bermudagrass grown on a golf course putting green in southern Florida, USA. Populations of total fungi, total bacteria, fluorescent pseudomonads, Stenotrophomonas maltophilia, actinomycetes and heat-tolerant bacteria were monitored every 3 months during the 2-year study. On only one sampling date and for only one bacterial population (S. maltophilia) was a significant difference in microbial populations obtained among the fertilizer treatments. However, the S. maltophilia populations associated with the natural organic fertilizer treatments were not significantly different from the synthetic organic IBDU fertilizer treatment.
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  • 67
    ISSN: 1437-3262
    Keywords: Key words Carbonates ; Cold seeps ; Methane ; Petroleum ; Archaea ; Bacteria ; Sponges ; Tube worms ; Epifluorescence ; Biomarkers ; Jurassic ; Tertiary ; France ; Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The relation of two well-known ancient carbonate deposits to hydrocarbon seepage was confirmed by this study. Archaea are found to be associated with the formation of Oxfordian seep carbonates from Beauvoisin and with a Miocene limestone from Marmorito ("tube-worm limestone"). Carbonates formed due to a mediation by archaea exhibit extremely positive or extremely negative δ13Ccarbonate values, respectively. Highly positive values (+15‰) reflect the use of 13C-enriched CO2 produced by methanogenesis. Low δ13C values of the Marmorito carbonates (–30‰) indicate the oxidation of seepage-derived hydrocarbons. Likewise, the δ13C content of specific tail-to-tail linked isoprenoids, biomarkers for archaea, was found to be strikingly depleted in these samples (as low as –115‰). The isotopic signatures corroborate that archaea were involved in the cycling of seepage-derived organic carbon at the ancient localities. Another Miocene limestone ("Marmorito limestone") shows a strong imprint of methanotrophic bacteria as indicated by δ13C values of carbonate as low as –40‰ and biomarker evidence. Epifluorescence microscopy and field-emission scanning electron microscopy revealed that bacterial biofilms were involved in carbonate aggregation. In addition to lucinid bivalves previously reported from both localities, we infer that sponges from Beauvoisin and tube worms from Marmorito depended on chemosynthesis as well. Low δ13C values of nodules related to sponge taphonomy (–27‰) indicate that sponges might have been linked to an enhanced hydrocarbon oxidation. Tube worm fossils from Marmorito closely resemble chemosynthetic pogonophoran tube worms from Recent cold seeps and are embedded in isotopically light carbonate (δ13C –30‰).
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  • 68
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    European biophysics journal 28 (1999), S. 263-267 
    ISSN: 1432-1017
    Keywords: Key words Human liver ; Human brain ; Ferritin ; Electron microscopy ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Human brain (globus pallidus) and liver tissues were investigated by means of electron microscopy (EM), Mössbauer spectroscopy (MS) and SQUID magnetometry techniques. Based on MS measurements, the iron present was identified to be in the ferritin-like form (61–88%) and in the form of a low-spin iron species (the balance). Its overall concentration was estimated as 1.5(3) mg in the brain and 2.4(5) mg in the liver, per gram of lyophilized tissue. The average core diameter was determined by EM measurements to be equal to 7.5(1.3) nm for the liver and 3.3(5) nm for the brain. Magnetization measurements carried out between 5 and 300 K yielded an estimation of an average blocking temperature, KT BL, as equal to 6.7 K and 8.5 K for the liver and the brain, respectively. From the dependence of KT BL on the external magnetic field it was concluded that the ferritin-like cores in the studied samples can be regarded as non-interacting particles. Finally, the uniaxial magnetic anisotropy constant was determined to be 6×103 J/m3 for the liver and 4×104 J/m3 for the brain.
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  • 69
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    Archives of microbiology 172 (1999), S. 213-218 
    ISSN: 1432-072X
    Keywords: Key words 16S rRNA gene sequences ; Phylogeny ; Bacteria ; Archaea ; Brines ; Kebrit Deep ; Red Sea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study, we report on first 16S rRNA gene sequences from highly saline brine sediments taken at a depth of 1,515 m in the Kebrit Deep, northern Red Sea. Microbial DNA extracted directly from the sediments was subjected to PCR amplification with primers specific for bacterial and archaeal 16S rRNA gene sequences. The PCR products were cloned, and a total of 11 (6 bacterial and 5 archaeal) clone types were determined by restriction endonuclease digestion. Phylogenetic analysis revealed that most of the cloned sequences were unique, showing no close association with sequences of cultivated organisms or sequences derived from environmental samples. The bacterial clone sequences form a novel phylogenetic lineage (KB1 group) that branches between the Aquificales and the Thermotogales. The archaeal clone sequences group within the Euryarchaeota. Some of the sequences cluster with the group II and group III uncultivated archaea sequence clones, while two clone groups form separate branches. Our results suggest that hitherto unknown archaea and bacteria may thrive in highly saline brines of the Red Sea under extreme environmental conditions.
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  • 70
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    Journal of mathematical biology 38 (1999), S. 359-375 
    ISSN: 1432-1416
    Keywords: Key words: Chemotaxis ; Partial differential equations ; Bacteria ; Mathematical Modeling ; Pattern formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract.  A variety of spatial patterns are formed chemotactically by the bacteria Escherichia coli and Salmonella typhimurium. We focus in this paper on patterns formed by E. coli and S. typhimurium in liquid medium experiments. The dynamics of the bacteria, nutrient and chemoattractant are modeled mathematically and give rise to a nonlinear partial differential equation system. We present a simple and intuitively revealing analysis of the patterns generated by our model. Patterns arise from disturbances to a spatially uniform solution state. A linear analysis gives rise to a second order ordinary differential equation for the amplitude of each mode present in the initial disturbance. An exact solution to this equation can be obtained, but a more intuitive understanding of the solutions can be obtained by considering the rate of growth of individual modes over small time intervals.
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  • 71
    ISSN: 1432-0878
    Keywords: Key words Descending contralateral movement detector (DCMD) ; Identified neuron ; Vesicles ; Electron microscopy ; 3-D reconstruction ; Locust ; Schistocercagregaria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The descending contralateral movement detector (DCMD), an identified descending interneuron in the brain of the locust Schistocerca gregaria has been investigated by using light and electron microscopy. We describe the fine structure, distribution and numbers of synapes that it receives from another identified brain neuron, the lobular giant movement detector (LGMD), and from unidentified neurons. The DCMD dendrites emerging from the integrative segment vary in form and number between individuals and sexes but always form a flattened dendritic domain. The arborizations and the integrative segment appear to be exclusively postsynaptic. Two types of synaptic contacts (Type 1 and 2) onto the DCMD can be discerned as having either round (Type 1) or pleiomorphic synaptic vesicles (Type 2) and by large (Type 1) or small (Type 2) subsynaptic appositions. Contact zones of Type 1 synapses are smaller than those of Type 2. LGMD-synapses are of Type 1 and occur intermingled with presynaptic sites of unidentified units. Some branches of the DCMD receiving input from unidentified units are devoid of contacting LGMD processes. Synapses of both types are randomly distributed over the DCMD integrative segment and at fibres with similar sizes.Type 1 synapses are much more frequent than Type 2 synapses and their number is negatively correlated with fibre diameter. For a whole DCMD dendritic arborization, a total of 8500 active zones of chemical synapses has been calculated, including a mininum of 2250 LGMD-synapses and about 1000 Type 2 synapses. The DCMD may thus receive a considerable amount of input from as yet unidentified neurons.
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  • 72
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    Cell & tissue research 296 (1999), S. 359-369 
    ISSN: 1432-0878
    Keywords: Key words Apoptosis ; Electron microscopy ; Meiosis ; Spermatocytes ; Spermatogenesis ; Testis ; TUNEL ; Mouse (10 strains)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Apoptosis of male germ cells is a widespread but little-understood phenomenon in many animal species. The elucidation of its mechanisms could be useful in the understanding of male infertility. We have examined the distribution of dying cells with the terminal transferase-mediated nick-end labeling (TUNEL) method and by an electron-microscopic procedure in the testes of 10 mouse strains, viz., C57BL/10 (B10), SL/NiA (SL), C57BL/6 (B6), C3H/He (C3H), BALB/c (BALB), DBA2 (DBA), CBA/J (CBA), MRL/MpJ-+/+ (M+), MRL/MpJ-lpr/lpr (lpr), and wild-type NJL mice (Mus musculus musculus). In the testes of the B10, NJL, SL, B6, C3H, BALB, DBA, and CBA mice, very few TUNEL-positive cells are distributed in the seminiferous tubules, whereas in the testes of the M+ and lpr mice, many TUNEL-positive cells, which are restricted to stage XII seminiferous tubules, have been identified. The most important finding is that many metaphases of meiotic spermatocytes show a marked TUNEL-positive reaction. Some metaphases show apoptotic morphology electron-microscopically. These results suggest that the testes of MRL strains will provide a useful model for the study of the mechanism of metaphase-specific apoptosis in meiotic spermatocytes.
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  • 73
    ISSN: 1432-0878
    Keywords: Key words Neuromelanin ; Neuron ; Peroxidase ; Oxygen metabolism ; High-definition light microscopy ; Electron microscopy ; Ultrastructure ; Cytochemistry ; Substantia nigra ; Lumbricusterrestris (Annelida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Histochemical examination of 1-μm tissue sections from the dorsal nerve plexus of the earthworm, Lumbricus terrestris, reveals multiple brown intraneuronal granules. These granules contain material morphologically and histochemically consistent with neuromelanin. When viewed with transmission electron microscopy, these were seen as single membrane-enclosed biphasic granules with diameters of 370–730 nm. Exposure of L. terrestris to high-level environmental oxygen resulted in an increase in the number of neuromelanin-like pigment granules within the neurons of the circular muscle layer. As measured by ortho-phenylenediamine hydrochloride, the endogenous peroxidase activity of extracts from worms incubated in high-level environmental oxygen was 51% more than controls. The endogenous peroxidase activity was localized in situ with 3,3-diaminobenzidine (DAB) and was found to increase in and around the neuromelanin-like pigment-containing neurons within the circular muscle layer. These studies suggest that the nerve net of L. terrestris may serve as a model to study the role of neuromelanin production in oxidative stress and its relationship to endogenous peroxidases.
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  • 74
    ISSN: 1432-0878
    Keywords: Key words Immunohistochemistry ; Electron microscopy ; Interstitial cells of Cajal ; F4/80 ; CSF-1 ; Kit-receptor ; Mouse (op/op)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The osteopetrotic (op/op) mutant mouse possesses an inactivating mutation in the colony-stimulating factor-1 (CSF-1) gene, which results in the absence of certain macrophages and in osteopetrosis, following a lack of osteoclasts. Studies of the op/op mouse indicate that CSF-1-dependent tissue macrophages may belong to a trophic and/or scavenger subpopulation, which through their effect on other cell types can significantly affect tissue functions, and that cells which are CSF-1 independent have antigen presentation and immunological functions.We have previously identified a cell system of regularly distributed macrophages in the muscularis externa of the small intestine and wanted to extend these studies to the op/op mouse.The present investigations with light- and electron-microscopic methods using fluorescent dextran, methylene blue and immunohistochemistry (F4/80, anti-kit receptor, anti-CD3, anti-CD45R/B220) show that macrophages are absent from the muscle layers, with only an occasional macrophage present in the subserosa. In the lamina propria and submucosa, macrophage numbers are reduced. In all other respects the muscularis externa appears normal, including normal organization and number of interstitial cells of Cajal. Control and op/op mice both lack cells expressing CD3 (T lymphocytes), CD45R/B220 (B lymphocytes) and mast cells in the muscularis externa. This leaves the muscularis externa macrophages as the most likely source of local cytokine production under such conditions as postoperative ileus and intussusception in infants, where the muscularis externa appears to be one target of cytokines. We conclude that the lack of macrophages, combined with the preservation of otherwise normal structure, will make the op/op mouse a valuable model by which to assess the functions and relative importance of the muscularis externa macrophages in relation to intestinal motility under normal and pathological conditions.
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  • 75
    ISSN: 1432-0878
    Keywords: Key words Caveolin ; Caveolae ; Lung ; Alveolar epithelial type I cell ; Immunocytochemistry ; Electron microscopy ; Confocal laser scanning microscopy ; Rat (CD)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Caveolae are flask-shaped invaginations of the plasmalemma which pinch off to form discrete vesicles within the cell cytoplasm. Biochemically, caveolae may be distinguished by the presence of a protein, caveolin, that is the principal component of filaments constituting their striated cytoplasmic coat. Squamous alveolar epithelial type I (ATI) cells, comprising approximately 95% of the surface area of lung alveolar epithelium, possess numerous plasmalemmal invaginations and cytoplasmic vesicles ultrastructurally indicative of caveolae. However, an ultrastructural appearance does not universally imply the biochemical presence of caveolin. This immunocytochemical study has utilised a novel application of confocal laser scanning and electron microscopy unequivocally to localise caveolin-1 to ATI cells. Further, cytoplasmic vesicles and flask-shaped membrane invaginations in the ATI cell were morphologically identified whose membranes were decorated with anti-caveolin-1 immunogold label. Coexistent with this, however, in both ATI and capillary endothelial cells could be seen membrane invaginations morphologically characteristic of caveolae, but which lacked associated caveolin immunogold label. This could reflect a true biochemical heterogeneity in populations of morphologically similar plasmalemmal invaginations or an antigen threshold requirement for labelling. The cuboidal alveolar epithelial type II cell (ATII) also displayed specific label for caveolin-1 but with no ultrastructural evidence for the formation of caveolae. The biochemical association of caveolin with ATI cell vesicles has broad implications for the assignment and further study of ATI cell function.
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  • 76
    ISSN: 1573-739X
    Keywords: Stability ; Buprenorphine ; Glycopyrrolate ; Haloperidol ; Polypropylene ; Polyvinyl chloride ; PVC ; Syringes ; Cassettes ; Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Combinations of opioids and adjuvant drug solutions are often used in clinical practice while little information is available on their microbiological or chemical stability. Currently there are no commercially available, prepacked, ready‐to‐use epidural or subcutaneous mixtures. Thus, epidural and subcutaneous analgesic mixtures must be prepared in the pharmacy on an as‐needed basis. Such mixtures are typically used for the treatment of severe pain in cancer patients. The aim of this study was to investigate the microbiological and chemical stability of a buprenorphine, haloperidol and glycopyrrolate mixture in a 0.9% sodium chloride solution. A high performance liquid chromatographic (HPLC) method and pH‐meter were used to conduct the analyses. Antimicrobial activity of each component was studied by an agar dilution method. According to the results from the chemical and microbiological stability studies, this mixture can be stored in polypropylene (PP) syringes and polyvinyl chloride (PVC) medication cassettes for at least 30 days at either 21 °C or 4 °C, and for 16 days in PP syringes at 36 °C, and for 9 days in PVC medication cassettes at 36 °C.
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  • 77
    ISSN: 1435-1536
    Keywords: Key words Double chain surfactants ; Aggregates ; Phase diagrams ; Lamellar phases ; Electron microscopy ; SANS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We present the phase diagrams and the properties of newly synthesised double-chain cationic N-alkyl-N-alkyl′-N,N-dimethylammonium bromide surfactants [C x C y DMABr (x = 12, 14 and 16; y = 10, 11, 12, 14 and 16)]. All the systems studied form liquid-crystalline lamellar phases but with different morphologies: unilamellar vesicles at low surfactant concentrations, multilamellar vesicles and tubular aggregates for surfactant concentrations between 2 and 10 wt% and at even higher concentrations planar bilayers of surfactant molecules in the classical Lα phase. The phase diagrams were determined with macroscopic and microscopic methods (polarisation microscopy, freeze-fracture transmission electron microscopy, scanning electron microscopy and differential interference contrast microscopy). The properties of the surfactant solutions were determined with differential scanning calorimetry measurements for Krafft point determination and small-angle neutron scattering measurements for interlamellar spacing and bilayer thickness. Finally, conductivity and viscosity measurements for phase characterisation were carried out.
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    Colloid & polymer science 277 (1999), S. 164-173 
    ISSN: 1435-1536
    Keywords: Keywords Nanostructures ; Thin films ; Vapor deposition ; Electron microscopy ; Optical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Colloidal dispersions of Yb, Er and Pr have been prepared by chemical liquid deposition. The metals were cocondensed at 77 K with 2-methoxyethanol and ethanol to produce solvated metal atoms. The particle size of the dispersions was determined by transmission electron microscopy to range from 52 to 1080 Å; the particles had spherical shapes. After solvent evaporation under vacuum, active solids and amorphous powder were deposited over Cu and Al metal. Dispersion stability, particle size, UV/Vis absorption and zeta potential were studied. The solids prepared by solvent evaporation were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The films prepared on Al were studied by scanning electron microscopy. The most stable colloid was obtained using 2-methoxyethanol: several concentrations were stable for several months and the zeta potential indicated that this colloid stability is mainly due to solvation effects. FTIR spectroscopy of the solids indicated solvent incorporation in the film. This observation was corroborated by thermal analysis. Information on the thermal stability of the films was obtained by TGA. The UV/Vis absorption spectrum was measured at several concentrations under different conditions.
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    World journal of microbiology and biotechnology 15 (1999), S. 7-10 
    ISSN: 1573-0972
    Keywords: Bacteria ; evolution ; molecular ; pairing ; recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract One principal function of biological molecules in bacteria is to recognize other molecules. This allows cells to assemble for regulated enzymatic catalysis and the integration of biochemical pathways. Recognition is also an essential and a specific property in base pairing of DNA in the double helix. Therefore, recognition events must have been central to early self-assembly of primitive genetic material, genomes, cells, genetic recombination and especially in enzyme-substrate-product recognition events. Molecular recognition events are examined with an emphasis on their central role in early prokaryotic evolution.
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    World journal of microbiology and biotechnology 15 (1999), S. 297-304 
    ISSN: 1573-0972
    Keywords: Bacteria ; cell ; diversity ; division ; Earth ; evolution ; metabolism ; self-assembly ; surfaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract About 80% of the evolutionary history of life on Earth is restricted to microorganisms which have had several billion years to speciate. The reasons for the origin (self-assembly) of life on Earth, bacterial cell division and why there are so many different bacteria and their global dispersal are discussed from an evolutionary perspective.
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  • 81
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    World journal of microbiology and biotechnology 15 (1999), S. 1-6 
    ISSN: 1573-0972
    Keywords: Bacteria ; conjugation ; DNA ; evolution ; gene transfer ; transduction ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The transfer of genetic information by transformation, conjugation and transduction in bacteria occurs frequently in nature. These diverse gene transfer mechanisms in bacteria are the result of evolution and are not linked to reproduction as in eukaryotic organisms. In this review, gene transfer in bacteria will be considered from an evolutionary perspective.
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  • 82
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    Biology and fertility of soils 26 (1998), S. 313-322 
    ISSN: 1432-0789
    Keywords: Key words Fungi ; Bacteria ; Nitrogen ; Scots pine ; Stratification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The abundance and micro-stratification of bacteria and fungi inhabiting the organic layers of a Scots pine forest (Pinus sylvestris L.) were investigated. An experiment using stratified litterbags, containing organic material of four degradation stages (fresh litter, litter, fragmented litter and humus) was performed over a period of 2.5 years. Dynamics and stratification of fluorescent stained bacteria and fungi, ratios between bacterial and fungal biomass, and relationships with moisture and temperature are described. Average bacterial counts in litter and fragmented litter were similar, i.e., approximately 5×109 bacteriag–1 (dry weight) organic matter, and significantly exceeded those in humus. The mean bacterial biomass ranged from 0.338 to 0.252mg carbon (C) g–1 (dry weight) organic matter. Lengths of mycelia were significantly below the usually recorded amounts for comparable temperate coniferous forests. The highest average hyphal length, 53mg–1 (dry weight) organic matter, was recorded in litter and decreased significantly with depth. The corresponding mean fungal biomass ranged from 0.050 to 0.009mg Cg–1 (dry weight). The abundance of bacteria and fungi was influenced by water content, that of fungi also by temperature. A litterbag series with freshly fallen litter of standard quality, renewed bimonthly, revealed a clear seasonal pattern with microbial biomass peaks in winter. The mean hyphal length was 104mg–1 (dry weight) and mean number of bacteria, 2.40×109 bacteria g–1 (dry weight). Comparable bacterial and fungal biomass C were found in the freshly fallen litter [0.154 and 0.132mgCg–1 (dry weight) organic material, respectively]. The ratio of bacterial-to-fungal biomass C increased from 1.2 in fresh litter to 28.0 in humus. The results indicate the existence of an environmental stress factor affecting the abundance of fungi in the second phase of decomposition. High atmospheric nitrogen deposition is discussed as a prime factor to explain low fungal biomass and the relatively short lengths of fungal hyphae in some of the forest soil layers under study.
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  • 83
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    Biology and fertility of soils 27 (1998), S. 149-154 
    ISSN: 1432-0789
    Keywords: Key words Marigold ; Tagetes ; Rhizosphere ; Nematode suppression ; Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Marigolds (genus Tagetes) suppress populations of soil endopathogenic nematodes such as Pratylenchus penetrans and Meloidogyne species. Nematode suppression by marigolds is thought to be due to thiophenes, heterocyclic sulfur-containing molecules abundant in this plant. When activated, thiophenes such as α-terthienyl produce oxygen radicals. If marigold roots release such a powerful biocidal agent and it is activated in soil, microbial populations in the marigold rhizosphere should be substantially perturbed. We made various measurements of microbial population size and activity in soils that had been cropped to marigolds (Crackerjack, Creole) in the field and in the greenhouse, and compared these with bare soil and soil cropped to rye (Secale cereale L.). Total extractable microbial biomass (measured by the fumigation extraction method), total bacteria (measured by epifluorescence microscopy on 5-(4,6-dichlorotriazine-2-γl) aminofluorescein-stained preparations), heterotrophic bacteria (measured by plate count on various media), and nitrite-oxidizing bacteria (measured by the most-probable-number method) were not significantly different in any of the treatments. Residues of 14C-labelled rye were mineralized slightly more rapidly in rye-cropped soil than in the other treatments, which were comparable. The rates of die-back of introduced cells of the bacteria Escherichia coli and Rhodococcus TE1 were similar in marigold-cropped and control soils, suggesting that there was not a noteworthy accumulation of biocidal agents in soils cropped to marigolds. We conclude that marigolds do not cause a general depression in the numbers of microorganisms in soils, and that nematode control by this plant may not be due to the release of a biocidal agent into the soil.
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  • 84
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    Biology and fertility of soils 26 (1998), S. 179-186 
    ISSN: 1432-0789
    Keywords: Key words Inoculation ; Bacteria ; Soil ; Community ; Changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of plant-growth-promoting rhizobacteria (PGPR) and spruce seedlings on the composition and activity of forest soil microbial communities was studied in a microcosm experiment in which sterile, sand-filled 25mm×150mm glass tubes were treated with a forest soil suspension containing Bacillus or Pseudomonas PGPR and 2-week-old spruce seedlings. Eighteen weeks after treatments were established, bacterial, actinomycete and fungal population sizes were determined by dilution plating, as were seedling dry weights and soil carbon substrate utilization profiles using Biolog plates. PGPR inoculation had little influence on the population sizes of actinomycetes or fungi. However, significant effects were detected on the total bacterial population size, primarily in microcosms without seedlings. Euclidean distances between treatments plotted on two dimensions by multidimensional scaling showed that the introduction of PGPR strains changed the type of microbial community, particularly when inoculated into soil without seedlings. Significant changes were also detected in one soil type in the presence of seedlings. Our results suggest that the type of soil community and the presence of seedlings are significant factors influencing the responses of soil communities to bacterial inoculation, and that for some soil communities, the presence of seedlings may mitigate perturbations caused by the introduction of PGPR.
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  • 85
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    Environmental geology 34 (1998), S. 257-269 
    ISSN: 1432-0495
    Keywords: Key words Colloids ; Particle size distribution ; Karstic aquifer ; Analytical techniques ; Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Colloids are known to transport contaminants over long distances in natural media. Despite this potentially harmful effect, very few studies have been undertaken in subsurface aquifers. This paper presents the first results of a study of natural colloids and particles in a karstic aquifer. The site was chosen for its coverage by clay layers and peat which deliver various and numerous particle types in water. The methodological part describes three methods used for size determination and sample fractionation of surface water and spring water. These methods have been adapted for the treatment of multiple samples due to the rapid discharge variation typical of karstic aquifers. The analysis of many particle size distributions (PSD) shows that they can be described by a Pareto law. The variation of the slope of the PSD at the spring is mainly dependent on discharge. This behavior is interpreted as a washing of the karstic drains during the first phase of high flow events. Fractionation of the samples allowed application of various characterization techniques to particle size classes. X-ray diffraction (XRD) patterns showed that most of the mineral particles originated from Quaternary deposits and limestones. However the use of scanning electron micrsocopy with energy-dispersive spectrometer (SEM-EDS) detailed the composition of individual particles and revealed particles not found by XRD. These techniques also showed the high complexity of the natural particles and the important place of coprecipitation in their formation. Consequences on the fluxes of particulate matter and its potential role as a carrier of contaminants are discussed.
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  • 86
    ISSN: 1432-0495
    Keywords: Key words Transport ; Bacteria ; Iron ; Groundwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Among the demonstrated processes influencing the transport of bacteria through aquifers, the deposition of cells on mineral surfaces is one of the most important. For example, understanding the transport of introduced bacteria through aquifers is essential to designing some in situ bioremediation schemes. The impact of the presence and distribution of Fe(III)-oxyhydroxide-coated sand grains on bacterial transport through porous media was evaluated in column experiments in which bacteria (short rods; 1.2 μm length) were eluted through columns of quartz sand (0.5–0.6 mm in diameter) for several conditions of chemical heterogeneity of mineral substrate. Fe(III)-oxyhydroxide-coated sand was present as 10% of the mass, and it was arranged in three treatments: (1) homogeneously distributed, and present as a discrete layer (2) at the top and (3) at the bottom of 14-cm-long sand columns. A pulse input of 108 cells ml–1 was introduced in an artificial groundwater solution flowing at 14 cm h–1 through the column, and eluted cells were counted. Peak breakthrough occurred at 1.0 pore volume. A large proportion of cells were retained; 14.7–15.8% of the cells were recovered after three pore volumes of solution had eluted through clean quartz sand, and only 2.1–4.0% were recovered from the Fe(III)-oxyhydroxide-coated sand mixtures. The three physical arrangements of the chemical heterogeneity resulted in essentially the same breakthrough of cells, indicating that the spatial distribution of iron coating does not affect the transport of bacteria. The results of the column transport experiments, which mimic hydrogeological conditions encountered in field problems, are consistent with our mechanistic understanding of bacterial sorption.
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  • 87
    ISSN: 1432-072X
    Keywords: Key wordsV. cholerae O139 ; Lipopolysaccharide ; Electron microscopy ; Freeze-substitution technique ; Capsule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphological and physical characteristics of the capsule of Vibrio cholerae O139 were examined. An electron microscopic study using the freeze-substitution technique showed that all of the V. cholerae strains of the O139 serogroup examined have a very thin fibrous layer on the outside of the outer membrane. In contrast, the mutants of strain O139, strain MO10T4 (which lacks capsule synthesis), and strain Bengal-2R1 (which fails to synthesize both the capsule and the O-antigen of lipopolysaccharide) were all found to have lost the surface layer. In addition, the capsule layer could also not be observed on the surface of V. cholerae strain O1. To determine the biological characteristics of the capsule of strains of the O139 serogroup, we investigated the serum killing activity and bacterial phagocytosis by polymorphonuclear leukocytes. The O139 strains were more resistant to the serum killing activity than were the V. cholerae O1 strain and the O139 mutant strains, thus suggesting that the existence of the capsule gave a serum-resistant character to the O139 strains. The surface character of the O139 strains had the same hydrophobic character as did that of the O139 mutant strains and the O1 strain. In addition, all the V. cholerae O1 and O139 strains examined, including the mutant strains, were effectively ingested by the human polymorphonuclear leukocytes. The number of ingested bacteria was not significantly different among the strains, and the ingestion of the acapsular O139 mutants thus showed that the capsule does not play an antiphagocytic role. These data suggest that the capsule of V. cholerae O139 has a physiological function different from that of the ordinal hydrophilic capsule that is found in invasive bacteria such as Klebsiella pneumoniae.
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  • 88
    ISSN: 1432-072X
    Keywords: Key words Magnetic bacteria ; Biomineralization ; Magnetite ; 16S rRNA ; In situ hybridization ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Natural enrichments of magnetic bacteria from the Itaipu lagoon near Rio de Janeiro were dominated by coccoid-to-ovoid morphotypes that produced unusually large magnetosomes. To determine the phylogenetic position of these unusual microorganisms, 16S rRNA genes were retrieved from bacteria magnetically separated from sediment of the Itaipu lagoon by in vitro amplification and cloning of PCR products into a plasmid vector. Partial sequencing of the obtained clones revealed two clusters of closely related sequences affiliated to a distinct lineage consisting exclusively of magnetic bacteria within the α-subclass of Proteobacteria. For a detailed phylogenetic analysis, several almost complete sequences of the 16S rRNA genes were determined. One representative clone of each cluster provided a PCR template for the in vitro transcription of group-specific polynucleotide probes complementary to a variable region of the 16S rRNA molecule. At least three different morphotypes of magnetic bacteria were reliably identified by post-embedding hybridization of ultra-thin sections. Electron microscopic analyses of hybridized cells enabled for the first time a detailed description of the morphological variety and ultrastructure of phylogenetically identified, uncultured magnetic bacteria. Two distinct coccoid bacteria were identified by the transcript probe complementary to the 16S rRNA sequence mabrj12, whereas the probe complementary to the sequence mabrj58 allowed the identification of an ovoid morphotype that displayed magnetosomes with the largest volumes observed to date.
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  • 89
    ISSN: 1432-9492
    Keywords: Transformation ; Clay-DNA complexes ; Nucleases ; X-ray diffraction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract DNA bound on clay minerals, sand, and humic acids has been shown, both in vitro and in situ, to be capable of transforming bacteria and to resist degradation by nucleases, which could result in the crypticity of genes in soil and other natural habitats. To determine where DNA is bound on clay minerals, which may help to explain how bound DNA becomes resistant to degradation by nucleases but retains the ability to transform competent cells, chromosomal DNA from Bacillus subtilis bound on montmorillonite (M) and kaolinite (K) was examined by X-ray diffractometry and transmission and scanning electron microscopy. X-ray diffraction analysis showed that the basal spacings of M and K were not altered, indicating that this DNA did not significantly intercalate the clays. Scanning and transmission electron microscopy showed that the binding of this DNA was primarily on the edges of M and K, although some binding was also apparent on the planar surfaces. Based on the results of these studies, it is postulated that: 1.extension from the edges of the clays enables the unbound end of DNA to interact with receptor sites on competent cells and result in their transformation; and 2.binding on clays alters the electron distribution and/or conformation of DNA, which reduces its hydrolysis by nucleases.
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  • 90
    ISSN: 1432-0878
    Keywords: Key words Prion protein (PrPc) ; Electron microscopy ; Secretory granules ; Membrane ; Extracerebral tissues ; Hamster ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  In transmissible spongiform encephalopathies (TSE), such as scrapie in animals and Creutzfeldt-Jakob disease in humans, the central event is the conversion of a host-encoded amyloidogenic protein (PrPc) into an abnormal isoform (PrPsc) that accumulates as amyloid in TSE brain. PrPc is a membrane sialoglycoprotein synthesized in the central nervous system and elsewhere. We have examined the ultrastructural localization of PrPc in numerous hamster and some human extracerebral tissues, by means of a post-embedding electron-microscopic method combined with immunogold labeling. In stomach, intestine, lung, and kidney from hamsters, and in stomach, kidney, and spleen from humans, immunogold labeling specific for PrPc is observed on various cellular substructures related to secretory pathways: Golgi apparatus, secretory globules, and plasma membrane. In mucous epithelial cells of stomach and intestine, PrPc appears to be concentrated in secretory globules, suggesting a role for PrPc in the secretory function of the digestive tract. The secretory aspect of PrPc may be a key to understanding the physiopathological mechanisms underlying TSE.
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  • 91
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    Cell & tissue research 293 (1998), S. 1-22 
    ISSN: 1432-0878
    Keywords: Key words Piecemeal degranulation ; Histamine ; Charcot-Leyden crystal protein ; Anaphylactic degranulation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The evidence for vesicular transport as a mechanism for secretion by human basophils is reviewed. Initially, direct electron-microscopic inspection of experimentally produced and sequentially biopsied contact allergy skin lesions revealed a unique form of secretion termed piecemeal degranulation, characterized by the slow emptying of secretory granule contents (with retention of empty containers) in the absence of extrusion of entire granules. Budding of small vesicles to/from secretory granules was observed, and cytoplasmic vesicles were abundant. A generalized degranulation model was proposed to unify classical regulated secretion and this new form of secretion. Investigation of the mechanism(s) of secretion from human basophils required the development of numerous tools and resources. Chief among these were: (a) isolation and purification of circulating basophils; (b) identification of specific growth factors to increase the supply of this rare granulocyte; (c) understanding of secretogogue mechanisms and reliable analyses of secreted basophil products; and (d) development of ultrastructural preparations allowing imaging of small vesicles and quantifiable small electron-dense tags for granule materials in small vesicles. Applications of these tools to well-defined models of basophil secretion have established a role for vesicles as a mechanism for effecting secretion of histamine and the Charcot-Leyden crystal protein from activated human basophils.
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  • 92
    ISSN: 1432-0878
    Keywords: Key words Dendritic cells ; Maturation ; Intrahepatic translocation ; Immunohistochemistry ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Specific populations of hepatic sinusoidal cells were stained with monoclonal antibodies that recognize monocytes/macrophages (ED1), tissue macrophages (Kupffer cells) (ED2), MHC class II (Ia) antigen (MRC OX6), and dendritic cells/γ,δ T-cells (MRC OX62) and analyzed by light and electron microscopy. The majority of ED1+ and/or ED2+ cells were localized to the hepatic parenchyma, whereas OX6+ and/or OX62+ cells were more densely distributed within Glisson’s sheath than in the hepatic parenchyma. Double-immunoperoxidase staining of normal liver for ED1, ED2, and OX6 identified dendritic cells (DC) of two different phenotypes, ED1+ED2–OX6+ and ED1–ED2–OX6+. DC can be classified into three different types based on ultrastructural characteristics. The first type (type I) is characterized by one or more long cytoplasmic processes and a well-developed lysosomal system. The second type (type II) has an inconspicuous lysosomal system, abundant hyaloplasm, and characteristic short cytoplasmic processes. The third type (type I–II) has cytologic features intermediate between those of type I and type II DC. At the electron-microscopic level, these three cell types are found in the sinusoidal lumen, whereas the majority of type II DC are located in the space of Disse and Glisson’s sheath. Furthermore, some OX6-labeled elongated DC appeared to traverse the lumen of sinusoids through endothelial pores to enter the space of Disse. One hour after intravenous injection of latex particles (0.81 μm in diameter), numerous latex-laden dendritic cells (ED1+OX6+, type I and type I–II) were detected in the lumen of hepatic sinusoids, but not in the space of Disse or Glisson’s sheath. These findings suggest that normal rat liver contains resident dendritic cells which downregulate phagocytic activity and mature into potent accessory cells during migration from the portal vein toward the central vein. These DC then traverse the sinusoidal lumen to the hepatic lymph system via the space of Disse.
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  • 93
    ISSN: 1617-4623
    Keywords: Key words Bacteriophage λ ; DnaA-DNA interactions ; Electron microscopy ; DNA-protein complexes ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Interaction of the Escherichia coli DnaA (replication initiator) protein with restriction fragments of phage λ DNA demonstrated differential binding of DnaA along the whole λ DNA. Interaction of DnaA with the λ replication region (from the promoter p R to the origin of replication, oriλ) demonstrated a strong binding of DnaA to the region around the p o promoter where synthesis of a short antisense oop RNA is initiated. The four sequences protected by DnaA (two 9mers and two 5mers) are not related even to a relaxed DnaA box. The pattern of protection of these four sequences and the location of three DNase I hypersensitive sites in the λ DNA r strand, together with results of mobility shift assays and electron microscopy studies, may indicate an interaction involving DnaA monomers bound to different DNA positions on one side of the helix and the formation of higher-order nucleoprotein structures. Therefore, it is tempting to suggest that DnaA, in addition to its activity in regulation of replication and transcription, could be considered as a factor which structures certain chromosomal regions.
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  • 94
    ISSN: 1615-6102
    Keywords: Sporopollenin ; Solubilisation ; 2-Aminoethanol ; Reaggregation ; Electron microscopy ; X-ray microscopy ; Thypha angustifolia L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Exines fromTypha angustifolia L. pollen were dissolved in hot 2-aminoethanol. The solubilisate was successively fractionated and reaggregated via a dialysis cascade with dialysis tubings of different exclusion volumina. Four fractions of reaggregated material with different molecular mass were obtained. Fraction 1 with a molecular mass above 25,000 Da, fraction 2 with a molecular mass between 10,000–25,000 Da, fraction 3 with a molecular mass between 5,000–10,000 Da, and fraction 4 of a molecular mass lower than 5,000 Da. The fractions were comparatively analysed by scanning and transmission electron microscopy and X-ray microscopy. The material of the fractions with a molecular mass above 10,000 Da exhibit high congruence to the initial material. Analysis of the reaggregated material with the lowest molecular mass revealed special distinct substructures which in form and size showed high similarities to substructures of exines described in literature. In detail, spherical substructures consisting of an electron-dense core surrounded by an electron-transparent corona and in addition elongated substructures with a distinctive surface sculpture were detected.
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  • 95
    ISSN: 1615-6102
    Keywords: Callose ; Electron microscopy ; Gasteria verrucosa ; Phenolics ; Phytomelan ; Seed coat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the seed coat ofGasteria verrucosa the deposition of phytomelan takes place during seed development in three stages. Phytomelan is a black cell wall material which is chemically very inert. First the radial walls and part of the transverse cell wall of the outer epidermis of the outer integument become thickened by exocytosis of dictyosome vesicles. Callose is deposited at the tangential plasma membrane against those walls. After the callose deposition about two thirds of the original cell volume is filled with callose. During the second stage the callose is broken down, probably into glucose monomers or small polymers. At the same time cellulose is deposited at the outer tangential plasma membrane, forming a wall between the dissolving callose and the plasma membrane. In the third phase small granules appear in the solution of dissolved callose. which grow out and finally fuse to form a block of phytomelan, consisting of spherical 15-nm units. Remarkable is the function of the callose: it determines the size of the phytomelan block, and it probably functions as carbohydrate source for the phytomelan synthesis and/or for the cellulose inner layer. In this study transmission electron microscopy and cryo scanning electron microscopy are used to study the three developmental stages of the formation of the phytomelan layer.
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  • 96
    ISSN: 1615-6102
    Keywords: Algae ; Virus assembly ; DAPI staining ; Electron microscopy ; Hincksia hincksiae ; Immunofluorescence ; Marine double-stranded DNA virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The filamentous brown algaHincksia hincksiae can be infected by a large icosahedral double-stranded DNA virus (HincV-1). The virus shows extended latency and is replicated only in cells homologous to sporangia. Virus formation was studied by transmission electron microscopy, DAPI staining, and β-tubulin immunofluorescence. Inhibition of cytokineses results in multinucleate cells, which are the first indication of virus replication in productive cells; the microtubular cytoskeleton does not seem to be affected by the virus. Replication of viral DNA begins in the nuclei, which increase in size and eventually disintegrate. Virus assembly takes place in a mixed nucleo-/cytoplasm. Capsids bud from cisternae, which are interpreted as modified endoplasmic reticulum aggregated to virus assembly centres. The internal membranous component of the virus is thus derived from the endoplasmic reticulum. The particles are empty (electron translucent) when assembled, and the nucleoprotein core seems to be packaged subsequently through an opening in the capsid. A number of fine structural features not previously reported from brown algae and related to virus formation are described. Our results on Hincksia hincksiae virus are compared with observations made on various other icosahedral DNA viruses infecting eukaryotic algae and animals.
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  • 97
    ISSN: 1573-0603
    Keywords: Adhesin ; Antibody ; Bacteria ; Fab ; Phage display
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Surface proteins provide a multitude of functions for the bacterial cell. Antibodies to these proteins can provide tools for tagging bacteria and characterizing protein function. Phage display technology has emerged as a powerful method for producing monoclonal Fabs in Escherichia coli. In an effort to study the adhesion mechanisms of Streptococcus parasanguis FW213, Fabs specific for the surface adhesin protein Fap1 were produced using phage display. The immune repertoire of a mouse injected with purified Fap1 was cloned into the phagemid vector pCOMB3, and a combinatorial Fab library was expressed in E. coli. A cell-based panning method using whole S. parasanguis cells was developed and has been shown to be a means for enriching for Fabs specific for the Fap1 protein.
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  • 98
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    Water, air & soil pollution 101 (1998), S. 45-67 
    ISSN: 1573-2932
    Keywords: Bacteria ; biodiversity ; chemically-contaminated ; ecology ; microorganisms ; molecular ; PCR ; soil ; toxic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Microorganisms isolated from soil are sources of known and new microorganisms and genetic material. This review examines general principles of soil bacterial biodiversity, limitations in sampling soils, and examples of bacterial diversity in chemically-contaminated soils. Both conventional and molecular methods used to assess microbial biodiversity in soils will be addressed as well as selected examples of the effects of organic and inorganic pollutants on soil microbial diversity.
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  • 99
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    World journal of microbiology and biotechnology 14 (1998), S. 853-856 
    ISSN: 1573-0972
    Keywords: Bacteria ; heavy metals ; mutation ; enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The objective of the present study was to obtain by mutation and selection techniques bacterial strains capable of removing heavy metals at high efficiency. Four of the bacteria most promising in metal uptake, Staphylococcus aureus, Bacillus Sphaericus, B. licheniformis and Arthrobacter sp. were selected after isolation from water heavily polluted with heavy metals. Two mutagenic agents were used: U.V. irradiation at 245nm (physical) and 1% ethidium bromide (chemical). Optimum conditions for metal removal by most of the tested bacteria were: pH 9, 50°C and 200rev/min agitation speed. Induction of mutation both physically or chemically resulted in mutants that were superior over their wild types in removing heavy metals under investigation. The highest removal efficiencies (REs) achieved were in the following order: Cd(89.9–100%); Cr(87.3–99.7%); Zn(47.7–100%); Cu(40.8–84.7%); Pb(40.2–51%); Fe(17.5–28.7%); Ni(13.8–23.9%) and finally Co(17.2–18.4%). Using mixed cultures of the wild and the selected mutants enhanced the RE(s) of some metals compared to those obtained by individual species, and the time required to achieve the highest RE was reduced.
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  • 100
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    Biology and fertility of soils 25 (1997), S. 354-360 
    ISSN: 1432-0789
    Keywords: Key words Substrate-induced respiration ; Selective ; inhibition ; Prokaryote:eukaryote ratio ; Arable soils ; Fungi ; Bacteria ; Cycloheximide ; Streptomycin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A procedure for the measurement of the fungal and bacterial contribution to substrate-induced respiration was tested in three arable soils. Glucose and different amounts of cycloheximide (eukaryote inhibitor) and streptomycin sulfate (prokaryote inhibitor) were added to soil suspensions, and respiration (CO2 evolution) was measured. Streptomycin sulfate concentrations from 10 to 120 mg ml–1 soil solution caused a stable inhibition of respiration. Amounts of cycloheximide ranging from 5 to 35 mg ml–1 showed an increasing inhibition. In a test with separate and combined addition of the antibiotics at maximum inhibitory concentrations, inhibition by streptomycin was completely overlapped by cycloheximide. This indicated non-target inhibition which may lead to overestimation of fungal respiration. Experiments with sterilized soils inoculated with either fungi or bacteria confirmed that streptomycin selectively inhibited bacteria. Cycloheximide, however, did not only inhibit fungal respiration already at 2 mg ml–1, but also increasingly inhibited bacterial respiration at increasing concentrations. Only at less than 5 mg cycloheximide ml–1 was the condition of selective fungal inhibition fulfilled. When 2 mg cycloheximide and 10 mg streptomycin sulfate ml–1 were applied, the sum of the separate inhibitions almost equalled the combined inhibition by the mix of both inhibitors in field samples. This method yielded fungal:bacterial respiration ratios of 0.50 to 0.60, and confirmed the dominance of bacteria in Dutch arable soils. The ratios obtained by the selective inhibitors were not correlated with, and were higher than, ratios of fungal:bacterial biovolume (0.19 to 0.46) as determined by microscopy and image analysis. Similar measurements in a forest soil (A-horizon) raised doubts on the reliability of the fungal inhibition by cycloheximide in this soil. It is concluded that the separate:combined inhibition ratio should always be checked, and comparison with other approaches is recommended.
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