K. Hanselmann - Academia.edu (original) (raw)
Papers by K. Hanselmann
Genome announcements, Jan 31, 2015
Here, we present the 3,443,800-bp complete genome sequence of Curtobacterium sp. strain MR_MD2014... more Here, we present the 3,443,800-bp complete genome sequence of Curtobacterium sp. strain MR_MD2014 (phylum Actinobacteria). This strain was isolated from soil in Woods Hole, MA, as part of the 2014 Microbial Diversity Summer Program at the Marine Biological Laboratory in Woods Hole, MA.
Physical Geography
Some ecological applications and energy budget calculations of the earth's surfac... more Some ecological applications and energy budget calculations of the earth's surface require accurate estimates of incoming longwave radiation, As cloud cover observations are not conducted frequently in high-mountain environments, a new model for the parameterization of daily mean incoming longwave radiation is proposed based on global radiation instead of cloud cover. Besides global radiation, the new model requires data for
Journal of General Microbiology
AIP Conference Proceedings, 2007
Les protozoaires se nourrissent volontiers de bactéries. Volontairement ou accidentellement, les ... more Les protozoaires se nourrissent volontiers de bactéries. Volontairement ou accidentellement, les micro-organismes sont disséminés dans l'environnement, et vivants ou morts ils entrent donc comme source nutritive dans la chaîne alimentaire. Jusqu'ici pratiquement aucun groupe de recherche ne s'est posé la question de savoir quelles peuvent en être les conséquences éventuelles. Il est connu que certaines bactéries responsables de maladies comme les salmonelles, les légionelles, les listéries ou les mycobactéries ne sont que très mal digérées par les unicellulaires animaux. Elles peuvent alors survivre longtemps dans leurs vacuoles, s'y multiplier puis retourner à l'environnement. Au cours de l'évolution les bactéries ont acquis la capacité d'échapper à la destruction programmée à l'intérieur des organelles digestives des unicellulaires. Elles ont donc aussi probablement " appris " comment elles peuvent échapper aux macrophages du système immun...
Schwerpunktprogramm Biotechnologie des Schweizerischen Nationalfonds zur Förderung der wissenscha... more Schwerpunktprogramm Biotechnologie des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung Nr. 11 Protozoen fressen gerne Bakterien. Mikroorganismen werden bewusst oder versehentlich in die Umwelt freigesetzt. Sie gelangen so als lebende oder tote Nahrungsquelle in die Nahrungskette. Ob davon potentielle Gefahren ausgehen, hat sich bisher kaum ein For-schungsteam gefragt. Es ist bekannt, dass einige krankheitserregende Bakterien, wie Salmonellen, Legionellen, Listerien oder Mycobakterien von tierischen Einzellern schlecht verdaut werden. Sie können unter Umständen längere Zeit in deren Verdauungsvakuolen überleben, sich dort vermehren und wieder in die Umwelt gelangen. Durch die während der Evolution erworbene Fähigkeit, der Zerstörung innerhalb der Verdauungsorganellen von Einzellern zu entkommen, " lernten " die Bakterien vermutlich auch, wie sie im menschlichen Organismus den Makrophagen des Immunsystems entkommen können. Ob innerhalb der Vakuol...
Detection Methods for Cynobacterial Toxins, 1994
New Trends in Research and Utilization of Solar Energy through Biological Systems, 1982
Applied and environmental microbiology, 1996
Until now, Escherichia coli was thought to be unable to develop natural competence, i.e., genetic... more Until now, Escherichia coli was thought to be unable to develop natural competence, i.e., genetic transformation could be achieved only artificially with the aid of nonphysiological concentrations of calcium ions or by other treatments. We have tested the competence development of E. coli through transformation under natural conditions in river water, springwater, and mineral water which contained between 0 and 11 mM Ca2+, using pUC18 DNA. The presence of calcium ions at concentrations as low as 1 to 2 mM was sufficient to obtain transformants. Variations in the temperature of incubation were not required for competence development but had an influence on the transformation frequency. Using water from mineral springs originating from calcareous regions, we have obtained transformation frequencies with laboratory strains of E. coli similar to those reported for other gram-negative bacteria known to develop natural competence. The competence development of E. coli is most probably int...
Applied and environmental microbiology, 1999
A new type of toxicity test based on the protozoan Tetrahymena pyriformis has been developed to a... more A new type of toxicity test based on the protozoan Tetrahymena pyriformis has been developed to assess the overall toxicity of bacterial strains given as prey. This simple and rapid test is able to detect toxicant-producing bacteria, which may present a biohazard. It can also be used for the risk assessment of microbes designed for deliberate release.
Applied and environmental microbiology, 1998
A new aerobic bacterium was isolated from the sediment of a freshwater pond close to a contaminat... more A new aerobic bacterium was isolated from the sediment of a freshwater pond close to a contaminated site at Amponville (France). It was enriched in a fixed-bed reactor fed with 2,6-dichlorophenol (2,6-DCP)as the sole carbon and energy source at pH 7.5 and room temperature. The degradation of 2,6-DCP followed Monod kinetics at low initial concentrations. At concentrations above 300 microM (50 mg.liter-1), 2,6-DCP increasingly inhibited its own degradation. The base sequence of the 16S ribosomal DNA allowed us to assign the bacterium to the genus Ralstonia (formerly Alcaligenes). The substrate spectrum of the bacterium includes toluene, benzene, chlorobenzene, phenol, and all four ortho- and para-substituted mono- and dichlorophenol isomers. Substituents other than chlorine prevented degradation. The capacity to degrade 2,6-DCP was examined in two fixed-bed reactors. The microbial population grew on and completely mineralized 2,6-DCP at 2,6-DCP concentrations up to 740 microM in conti...
Schweizer Archiv für Tierheilkunde, 1997
The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-... more The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-disciplinary approach. Certain small rivers and ponds located in the affected Alpine pastures in the areas of Misox, Rheinwald and Engadin provide favourable habitats for the growth of hepatotoxic cyanobacteria, particularly during long periods of hot and dry weather. As cattle frequently take up water from these sources, the toxins produced by cyanobacteria may lead to lethal poisonings that are typically associated with hemorrhagic liver necrosis. The latest reported case of cyanobacteria poisoning of Alpine cattle occurred during the summer of 1996. Further animal losses may be avoided by the implementation of appropriate pasture management schemes. To identify sites of potential hazards to human or animal health, we have developed a sensitive screening assay for the detection of cyanobacteria hepatotoxins in algae and water samples.
Schweizer Archiv für Tierheilkunde, 1994
ABSTRACT We measured the carbonate associated sulfate (CAS: sulfate trapped in the carbonate crys... more ABSTRACT We measured the carbonate associated sulfate (CAS: sulfate trapped in the carbonate crystal lattice at the time of precipitation) in a ~51 myo stromatolite from the Tipton-Wilkins Peak contact in the Greater Green River Basin in southern Wyoming. The 8-cm-thick microdigitate stromatolite contained two alternating microstructures: a precipitated carbonate fan fabric and a micritic fabric (including trapped detrital grains). CAS values for the precipitated layers clustered narrowly between 392-431ppm; given the precipitated fabric, we suggest that CAS reflects lake chemistry at the time of formation. Adjacent micritic layers, on the other hand, had much greater variation (321-3479ppm) and substantially higher average values per layer (519- 1170ppm); we hypothesize that these values probably may not represent actual lake evaporative environments, the likely source of the micrite. We used average CAS values in the precipitated layers to estimate sulfate concentrations in the Greater Green River Basin at the time of carbonate formation using a CAS vs. sulfate concentration relationship established in a modern analog system at Walker Lake, Nevada. Our analysis suggests that lake sulfate was ~1.5mM, implying a moderate level of sulfate. Better constraints on the rate of carbonate formation and the depth-to-volume relationships of the lake basin are required before quantitative lake depth fluctuation calculations can be done. In lakes where this information is well-constrained, CAS could be used to determine lake volume fluctuations on relatively fine timescales. However, care is required to ensure that grains tested are representative of the in situ environment (e.g. not detrital or shell material).
The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone ... more The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone National Park occurs at a rapid rate, whereby microorganisms that colonize the ponds and apron facies are required to overcome lithification. CO2-fixation by autotrophic microorganisms in this cation-rich environment further promotes carbonate encapsulation. Microorganisms that alter their micro-habitat through dissimilative metabolic processes such as H2S and
Genome announcements, Jan 13, 2014
Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns t... more Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity.
Genome announcements, Jan 31, 2015
Here, we present the 3,443,800-bp complete genome sequence of Curtobacterium sp. strain MR_MD2014... more Here, we present the 3,443,800-bp complete genome sequence of Curtobacterium sp. strain MR_MD2014 (phylum Actinobacteria). This strain was isolated from soil in Woods Hole, MA, as part of the 2014 Microbial Diversity Summer Program at the Marine Biological Laboratory in Woods Hole, MA.
Physical Geography
Some ecological applications and energy budget calculations of the earth's surfac... more Some ecological applications and energy budget calculations of the earth's surface require accurate estimates of incoming longwave radiation, As cloud cover observations are not conducted frequently in high-mountain environments, a new model for the parameterization of daily mean incoming longwave radiation is proposed based on global radiation instead of cloud cover. Besides global radiation, the new model requires data for
Journal of General Microbiology
AIP Conference Proceedings, 2007
Les protozoaires se nourrissent volontiers de bactéries. Volontairement ou accidentellement, les ... more Les protozoaires se nourrissent volontiers de bactéries. Volontairement ou accidentellement, les micro-organismes sont disséminés dans l'environnement, et vivants ou morts ils entrent donc comme source nutritive dans la chaîne alimentaire. Jusqu'ici pratiquement aucun groupe de recherche ne s'est posé la question de savoir quelles peuvent en être les conséquences éventuelles. Il est connu que certaines bactéries responsables de maladies comme les salmonelles, les légionelles, les listéries ou les mycobactéries ne sont que très mal digérées par les unicellulaires animaux. Elles peuvent alors survivre longtemps dans leurs vacuoles, s'y multiplier puis retourner à l'environnement. Au cours de l'évolution les bactéries ont acquis la capacité d'échapper à la destruction programmée à l'intérieur des organelles digestives des unicellulaires. Elles ont donc aussi probablement " appris " comment elles peuvent échapper aux macrophages du système immun...
Schwerpunktprogramm Biotechnologie des Schweizerischen Nationalfonds zur Förderung der wissenscha... more Schwerpunktprogramm Biotechnologie des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung Nr. 11 Protozoen fressen gerne Bakterien. Mikroorganismen werden bewusst oder versehentlich in die Umwelt freigesetzt. Sie gelangen so als lebende oder tote Nahrungsquelle in die Nahrungskette. Ob davon potentielle Gefahren ausgehen, hat sich bisher kaum ein For-schungsteam gefragt. Es ist bekannt, dass einige krankheitserregende Bakterien, wie Salmonellen, Legionellen, Listerien oder Mycobakterien von tierischen Einzellern schlecht verdaut werden. Sie können unter Umständen längere Zeit in deren Verdauungsvakuolen überleben, sich dort vermehren und wieder in die Umwelt gelangen. Durch die während der Evolution erworbene Fähigkeit, der Zerstörung innerhalb der Verdauungsorganellen von Einzellern zu entkommen, " lernten " die Bakterien vermutlich auch, wie sie im menschlichen Organismus den Makrophagen des Immunsystems entkommen können. Ob innerhalb der Vakuol...
Detection Methods for Cynobacterial Toxins, 1994
New Trends in Research and Utilization of Solar Energy through Biological Systems, 1982
Applied and environmental microbiology, 1996
Until now, Escherichia coli was thought to be unable to develop natural competence, i.e., genetic... more Until now, Escherichia coli was thought to be unable to develop natural competence, i.e., genetic transformation could be achieved only artificially with the aid of nonphysiological concentrations of calcium ions or by other treatments. We have tested the competence development of E. coli through transformation under natural conditions in river water, springwater, and mineral water which contained between 0 and 11 mM Ca2+, using pUC18 DNA. The presence of calcium ions at concentrations as low as 1 to 2 mM was sufficient to obtain transformants. Variations in the temperature of incubation were not required for competence development but had an influence on the transformation frequency. Using water from mineral springs originating from calcareous regions, we have obtained transformation frequencies with laboratory strains of E. coli similar to those reported for other gram-negative bacteria known to develop natural competence. The competence development of E. coli is most probably int...
Applied and environmental microbiology, 1999
A new type of toxicity test based on the protozoan Tetrahymena pyriformis has been developed to a... more A new type of toxicity test based on the protozoan Tetrahymena pyriformis has been developed to assess the overall toxicity of bacterial strains given as prey. This simple and rapid test is able to detect toxicant-producing bacteria, which may present a biohazard. It can also be used for the risk assessment of microbes designed for deliberate release.
Applied and environmental microbiology, 1998
A new aerobic bacterium was isolated from the sediment of a freshwater pond close to a contaminat... more A new aerobic bacterium was isolated from the sediment of a freshwater pond close to a contaminated site at Amponville (France). It was enriched in a fixed-bed reactor fed with 2,6-dichlorophenol (2,6-DCP)as the sole carbon and energy source at pH 7.5 and room temperature. The degradation of 2,6-DCP followed Monod kinetics at low initial concentrations. At concentrations above 300 microM (50 mg.liter-1), 2,6-DCP increasingly inhibited its own degradation. The base sequence of the 16S ribosomal DNA allowed us to assign the bacterium to the genus Ralstonia (formerly Alcaligenes). The substrate spectrum of the bacterium includes toluene, benzene, chlorobenzene, phenol, and all four ortho- and para-substituted mono- and dichlorophenol isomers. Substituents other than chlorine prevented degradation. The capacity to degrade 2,6-DCP was examined in two fixed-bed reactors. The microbial population grew on and completely mineralized 2,6-DCP at 2,6-DCP concentrations up to 740 microM in conti...
Schweizer Archiv für Tierheilkunde, 1997
The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-... more The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-disciplinary approach. Certain small rivers and ponds located in the affected Alpine pastures in the areas of Misox, Rheinwald and Engadin provide favourable habitats for the growth of hepatotoxic cyanobacteria, particularly during long periods of hot and dry weather. As cattle frequently take up water from these sources, the toxins produced by cyanobacteria may lead to lethal poisonings that are typically associated with hemorrhagic liver necrosis. The latest reported case of cyanobacteria poisoning of Alpine cattle occurred during the summer of 1996. Further animal losses may be avoided by the implementation of appropriate pasture management schemes. To identify sites of potential hazards to human or animal health, we have developed a sensitive screening assay for the detection of cyanobacteria hepatotoxins in algae and water samples.
Schweizer Archiv für Tierheilkunde, 1994
ABSTRACT We measured the carbonate associated sulfate (CAS: sulfate trapped in the carbonate crys... more ABSTRACT We measured the carbonate associated sulfate (CAS: sulfate trapped in the carbonate crystal lattice at the time of precipitation) in a ~51 myo stromatolite from the Tipton-Wilkins Peak contact in the Greater Green River Basin in southern Wyoming. The 8-cm-thick microdigitate stromatolite contained two alternating microstructures: a precipitated carbonate fan fabric and a micritic fabric (including trapped detrital grains). CAS values for the precipitated layers clustered narrowly between 392-431ppm; given the precipitated fabric, we suggest that CAS reflects lake chemistry at the time of formation. Adjacent micritic layers, on the other hand, had much greater variation (321-3479ppm) and substantially higher average values per layer (519- 1170ppm); we hypothesize that these values probably may not represent actual lake evaporative environments, the likely source of the micrite. We used average CAS values in the precipitated layers to estimate sulfate concentrations in the Greater Green River Basin at the time of carbonate formation using a CAS vs. sulfate concentration relationship established in a modern analog system at Walker Lake, Nevada. Our analysis suggests that lake sulfate was ~1.5mM, implying a moderate level of sulfate. Better constraints on the rate of carbonate formation and the depth-to-volume relationships of the lake basin are required before quantitative lake depth fluctuation calculations can be done. In lakes where this information is well-constrained, CAS could be used to determine lake volume fluctuations on relatively fine timescales. However, care is required to ensure that grains tested are representative of the in situ environment (e.g. not detrital or shell material).
The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone ... more The precipitation of carbonates in the travertine forming Narrow Gauge hot spring in Yellowstone National Park occurs at a rapid rate, whereby microorganisms that colonize the ponds and apron facies are required to overcome lithification. CO2-fixation by autotrophic microorganisms in this cation-rich environment further promotes carbonate encapsulation. Microorganisms that alter their micro-habitat through dissimilative metabolic processes such as H2S and
Genome announcements, Jan 13, 2014
Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns t... more Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity.