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Thomas Rohrlack - One of the best experts on this subject based on the ideXlab platform.
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the red queen race between parasitic chytrids and their host planktothrix a test using a time series reconstructed from sediment dna
PLOS ONE, 2015Co-Authors: Marcia Kyle, Sigrid Haande, Veronika Ostermaier, Thomas RohrlackAbstract:Parasitic chytrid fungi (phylum Chytridiomycota) are known to infect specific phytoplankton, including the filamentous cyanobacterium Planktothrix. Subspecies, or chemotypes of Planktothrix can be identified by the presence of characteristic Oligopeptides. Some of these Oligopeptides can be associated with important health concerns due to their potential for toxin production. However, the relationship between chytrid parasite and Planktothrix host is not clearly understood and more research is needed. To test the parasite - host relationship over time, we used a sediment core extracted from a Norwegian lake known to contain both multiple Planktothrix chemotype hosts and their parasitic chytrid. Sediment DNA of chytrids and Planktothrix was amplified and a 35-year coexistence was found. It is important to understand how these two antagonistic species can coexistence in a lake. Reconstruction of the time series showed that between 1979–1990 at least 2 strains of Planktothrix were present and parasitic pressure exerted by chytrids was low. After this period one chemotype became dominant and yet showed continued low susceptibility to chytrid parasitism. Either environmental conditions or intrinsic characteristics of Planktothrix could have been responsible for this continued dominance. One possible explanation could be found in the shift of Planktothrix to the metalimnion, an environment that typically consists of low light and decreased temperatures. Planktothrix are capable of growth under these conditions while the chytrid parasites are constrained. Another potential explanation could be due to the differences between cellular oligopeptide variations found between Planktothrix chemotypes. These Oligopeptides can function as defense systems against chytrids. Our findings suggest that chytrid driven diversity was not maintained over time, but that the combination of environmental constraints and multiple oligopeptide production to combat chytrids could have allowed one Planktothrix chemotype to have dominance despite chytrid presence.
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putative antiparasite defensive system involving ribosomal and nonribosomal Oligopeptides in cyanobacteria of the genus planktothrix
Applied and Environmental Microbiology, 2013Co-Authors: Thomas Rohrlack, Guntram Christiansen, Rainer KurmayerAbstract:Parasitic chytrid fungi can inflict significant mortality on cyanobacteria but frequently fail to keep cyanobacterial dominance and bloom formation in check. Our study tested whether oligopeptide production, a common feature in many cyanobacteria, can be a defensive mechanism against chytrid parasitism. The study employed the cyanobacterial strain Planktothrix NIVA-CYA126/8 and its mutants with knockout mutations for microcystins, anabaenopeptins, and microviridins, major oligopeptide classes to be found in NIVA-CYA126/8. Four chytrid strains were used as parasite models. They are obligate parasites of Planktothrix and are unable to exploit alternative food sources. All chytrid strains were less virulent to the NIVA-CYA126/8 wild type than to at least one of its oligopeptide knockout mutants. One chytrid strain even failed to infect the wild type, while exhibiting considerable virulence to all mutants. It is therefore evident that producing microcystins, microviridins, and/or anabaenopeptins can reduce the virulence of chytrids to Planktothrix, thereby increasing the host's chance of survival. Microcystins and anabaenopeptins are nonribosomal Oligopeptides, while microviridins are produced ribosomally, suggesting that Planktothrix resists chytrids by relying on metabolites that are produced via distinct biosynthetic pathways. Chytrids, on the other hand, can adapt to the Oligopeptides produced by Planktothrix in different ways. This setting most likely results in an evolutionary arms race, which would probably lead to Planktothrix and chytrid population structures that closely resemble those actually found in nature. In summary, the findings of the present study suggest oligopeptide production in Planktothrix to be part of a defensive mechanism against chytrid parasitism.
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distribution of oligopeptide chemotypes of the cyanobacterium planktothrix and their persistence in selected lakes in fennoscandia 1
Journal of Phycology, 2009Co-Authors: Thomas Rohrlack, Randi Skulberg, Olav M SkulbergAbstract:Eighty-seven Planktothrix (Anagnostidis and Komarek 1988) strains isolated from 13 lakes in Scandinavia and Finland between 1964 and 2007 were screened for Oligopeptides. Forty-six individual compounds were detected in total, belonging to the structural classes anabaenopeptins (six variants), aeruginosins (six variants), cyanopeptolins (21 variants), microcystins (five variants), microginins (two variants), and microviridins (two variants). Oscillatorin was also found. Three additional compounds could not be assigned to known oligopeptide classes. Thirty Oligopeptides have not been described in previous studies. Of these new compounds, five were aeruginosins and 20 cyanopeptolins. The number of Oligopeptides per strain ranged from one to 13. No oligopeptide-free strains were found, suggesting that oligopeptide production is vital for Planktothrix. On the basis of their oligopeptide patterns, the Planktothrix strains of the present study were assigned to 17 chemotypes. Three major chemotypes occurred in up to six lakes. One chemotype occurred in lakes around the city of Oslo (Norway), on the Finnish island Fasta Aland, which is situated in the Baltic Sea, and on the Finnish mainland. This wide distribution suggests that chemotypes can be subjects of recurrent dispersal and/or strong directional selection. Lake size, maximum depth, and nutrient availability appeared to be of minor importance for the ability of some chemotypes to colonize a water body successfully as long as the general requirements of Planktothrix were met. Four chemotypes were reisolated from the Oslo lake district over a period of 33–40 years, suggesting that they have been members of local Planktothrix populations for decades.
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oligopeptide chemotypes of the toxic freshwater cyanobacterium planktothrix can form sub populations with dissimilar ecological traits
Limnology and Oceanography, 2008Co-Authors: Thomas Rohrlack, Camilla Blikstad Halstvedt, Robert Ptacnik, Randi Skulberg, Hans Utkilen, Bente Edvardsen, Olav M SkulbergAbstract:Nonribosomal Oligopeptides were used as qualitative and quantitative markers to test whether populations of the toxic freshwater cyanobacterium Planktothrix comprise subpopulations with dissimilar ecological traits. A field program was conducted in Lake Steinsfjorden (Norway), where Planktothrix has dominated the phytoplankton community for decades, allowing the present study to disregard other potential producers of nonribosomal Oligopeptides. Four chemotypes with distinct cellular oligopeptide patterns were found in the lake. The chemotypes occurred largely unaltered throughout a period of up to 33 yr and differed with respect to seasonal dynamics, depth distribution, and participation in loss processes. Changes in the relative abundance of chemotypes occurred almost constantly and could not be explained with fluctuations in light, temperature, or concentration of macronutrients but might have been due to differences among chemotypes in depth regulation or interaction with grazers or pathogens. Chemotypes correlated weakly with taxonomic groups and genotypes defined on the basis of phycocyanin operon deoxyribonucleic acid (DNA) sequences. Our findings suggest that first, oligopeptide chemotypes can have dissimilar ecological traits and therefore interact differently with their environment; second, populations of toxic freshwater cyanobacteria can comprise multiple ecologically distinct subpopulations; and, third, the relative abundance of these may vary, causing a high variability in wholepopulation properties. The latter was demonstrated for the microcystin-related toxicity of Planktothrix. The consequences of the present findings for the taxonomy of Planktothrix are discussed.
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on the effect of abiotic environmental factors on production of bioactive Oligopeptides in field populations of planktothrix spp cyanobacteria
Journal of Plankton Research, 2008Co-Authors: Camilla Blikstad Halstvedt, Robert Ptacnik, Thomas Rohrlack, Bente EdvardsenAbstract:The variability in abundance of bioactive Oligopeptides in Planktothrix spp. biomass in Lake Steinsfjorden, Norway, was examined for the period May 2003-August 2004, both temporally (over the year) and spatially (by depth). Of the 33 Oligopeptides recorded, desmethyl-microcystin RR and LR, anabaenopeptin B, aeruginosin 583, oscillamide Y, oscillaginin B and oscillapeptin G were studied in detail. Of these desmethyl-microcystin RR had the highest average concentration (2.5 ± 3.0 μg L −1 ) and showed similar distributional patterns as the Planktothrix spp. biomass. Multivariate regression models, called generalized additive models (GAMs), were used to investigate the effect of temperature, irradiance, macronutrients, depth and date on the cellular oligopeptide content of Planktothrix spp. GAMs explained between 50 and 94% of the total variance in the abundance of Oligopeptides per unit Planktothrix spp. biomass and also ranked parameters according to their contribution to this variance. Date was the most important contributor, linked to the waxing and waning of the four Planktothrix chemotypes found in Lake Steinsfjorden. There was an overall trend of increase in oligopeptide abundances per unit Planktothrix spp. biomass by depth. The factors affecting growth, temperature, irradiance and macronutrients had only a minor effect, explaining on average less than 10% of the variance included in the statistical models. The various classes of Oligopeptides appeared to be influenced by environmental factors in a similar manner, suggesting that these Oligopeptides may have a similar function in cyanobacteria.
W N Konings - One of the best experts on this subject based on the ideXlab platform.
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Oligopeptides are the main source of nitrogen for lactococcus lactis during growth in milk
Applied and Environmental Microbiology, 1995Co-Authors: Vincent Juillard, W N Konings, Le D Bars, Edmund R S Kunji, J C Gripon, J RichardAbstract:The consumption of amino acids and peptides was monitored during growth in milk of proteinase-positive (Prt+) and -negative (Prt-) strains of Lactococcus lactis. The Prt- strains showed monophasic exponential growth, while the Prt+ strains grew in two phases. The first growth phases of the Prt+ and Prt- strains were in same, and no hydrolysis of casein was observed. Also, the levels of consumption of amino acids and peptides in the Prt+ and Prt- strains were similar. At the end of this growth phase, not all free amino acids and peptides were used, indicating that the remaining free amino acids and peptides were unable to sustain growth. The consumption of free amino acids was very low (about 5 mg/liter), suggesting that these nitrogen sources play only a minor role in growth. Oligopeptide transport-deficient strains (Opp-) of L. lactis were unable to utilize Oligopeptides and grew poorly in milk. However, a di- and tripeptide transport-deficient strain (DtpT-) grew exactly like the wild type (Opp+ Dtpt+) did. These observations indicate that Oligopeptides represent the main nitrogen source for growth in milk during the first growth phase. In the second phase of growth of Prt+ strains, milk proteins are hydrolyzed to peptides by the proteinase. Several of the Oligopeptides formed are taken up and hydrolyzed internally by peptidases to amino acids, several of which are subsequently released into the medium (see also E.R.S. Kunji, A. Hagting, C.J. De Vries, V. Juillard, A.J. Haandrikman, B. Poolman, and W.N. Konings, J. Biol. Chem. 270:1569-1574, 1995).(ABSTRACT TRUNCATED AT 250 WORDS)
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the extracellular pi type proteinase of lactococcus lactis hydrolyzes beta casein into more than one hundred different Oligopeptides
Journal of Bacteriology, 1995Co-Authors: V Juillard, Edmund R S Kunji, Harry Laan, C M Jeronimusstratingh, A P Bruins, W N KoningsAbstract:The peptides released from beta-casein by the action of PI-type proteinase (PrtP) from Lactococcus lactis subsp. cremoris Wg2 have been identified by on-line coupling of liquid chromatography to mass spectrometry. After 24 h of incubation of beta-casein with purified PrtP, a stable mixture of peptides was obtained. The trifluoroacetic acid-soluble peptides of this beta-casein hydrolysate were fractionated by high-performance liquid chromatography and introduced into the liquid chromatography-ion spray mass spectrometry interface. Multiply charged ions were generated from trifluoroacetic acid-soluble peptides under low nozzle voltage conditions, yielding the MH+ mass of each eluted peptide. All peptides corresponding to each of the MH+ calculated masses were determined. In those cases in which different peptides were possible, further identification was achieved by collision-induced dissociation under higher nozzle voltage conditions. Hydrolysis of beta-casein by PrtP was observed to proceed much further than reported previously. More than 40% of the peptide bonds are cleaved by PrtP, resulting in the formation of more than 100 different Oligopeptides. With the exception of Phe, significant release of amino acids or di- and tripeptides could not be observed. Interestingly, one-fifth of the identified Oligopeptides are small enough to be taken up by the oligopeptide transport system. Uptake of these peptides could supply L. lactis with all amino acids, including the essential ones, indicating that growth of L. lactis might be possible on peptides released from beta-casein by proteinase only.
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di tripeptides and Oligopeptides are taken up via distinct transport mechanisms in lactococcus lactis
Journal of Bacteriology, 1993Co-Authors: E R S Kunji, Ej Smid, R Plapp, Berend Poolman, W N KoningsAbstract:Lactococcus lactis ML3 possesses two different peptide transport systems of which the substrate size restriction and specificity have been determined. The first system is the earlier-described proton motive force-dependent di-tripeptide carrier (E. J. Smid, A. J. M. Driessen, and W. N. Konings, J. Bacteriol. 171:292-298, 1989). The second system is a metabolic energy-dependent oligopeptide transport system which transports peptides of four to at least six amino acid residues. The involvement of a specific oligopeptide transport system in the utilization of tetra-alanine and penta-alanine was established in a mutant of L. lactis MG1363 that was selected on the basis of resistance to toxic analogs of alanine and alanine-containing di- and tripeptides. This mutant is unable to transport alanine, dialanine, and trialanine but still shows uptake of tetra-alanine and penta-alanine. The oligopeptide transport system has a lower activity than the di-tripeptide transport system. Uptake of Oligopeptides occurs in the absence of a proton motive force and is specifically inhibited by vanadate. The oligopeptide transport system is most likely driven by ATP or a related energy-rich, phosphorylated intermediate.
Michael Hust - One of the best experts on this subject based on the ideXlab platform.
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Oligopeptide M13 phage display in pathogen research
Viruses, 2013Co-Authors: Jonas Kügler, Torsten Meyer, Jonas Zantow, Michael HustAbstract:Phage display has become an established, widely used method for selection of peptides, antibodies or alternative scaffolds. The use of phage display for the selection of antigens from genomic or cDNA libraries of pathogens which is an alternative to the classical way of identifying immunogenic proteins is not well-known. In recent years several new applications for oligopeptide phage display in disease related fields have been developed which has led to the identification of various new antigens. These novel identified immunogenic proteins provide new insights into host pathogen interactions and can be used for the development of new diagnostic tests and vaccines. In this review we focus on the M13 oligopeptide phage display system for pathogen research but will also give examples for lambda phage display and for applications in other disease related fields. In addition, a detailed technical work flow for the identification of immunogenic Oligopeptides using the pHORF system is given. The described identification of immunogenic proteins of pathogens using oligopeptide phage display can be linked to antibody phage display resulting in a vaccine pipeline.
Olav M Skulberg - One of the best experts on this subject based on the ideXlab platform.
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distribution of oligopeptide chemotypes of the cyanobacterium planktothrix and their persistence in selected lakes in fennoscandia 1
Journal of Phycology, 2009Co-Authors: Thomas Rohrlack, Randi Skulberg, Olav M SkulbergAbstract:Eighty-seven Planktothrix (Anagnostidis and Komarek 1988) strains isolated from 13 lakes in Scandinavia and Finland between 1964 and 2007 were screened for Oligopeptides. Forty-six individual compounds were detected in total, belonging to the structural classes anabaenopeptins (six variants), aeruginosins (six variants), cyanopeptolins (21 variants), microcystins (five variants), microginins (two variants), and microviridins (two variants). Oscillatorin was also found. Three additional compounds could not be assigned to known oligopeptide classes. Thirty Oligopeptides have not been described in previous studies. Of these new compounds, five were aeruginosins and 20 cyanopeptolins. The number of Oligopeptides per strain ranged from one to 13. No oligopeptide-free strains were found, suggesting that oligopeptide production is vital for Planktothrix. On the basis of their oligopeptide patterns, the Planktothrix strains of the present study were assigned to 17 chemotypes. Three major chemotypes occurred in up to six lakes. One chemotype occurred in lakes around the city of Oslo (Norway), on the Finnish island Fasta Aland, which is situated in the Baltic Sea, and on the Finnish mainland. This wide distribution suggests that chemotypes can be subjects of recurrent dispersal and/or strong directional selection. Lake size, maximum depth, and nutrient availability appeared to be of minor importance for the ability of some chemotypes to colonize a water body successfully as long as the general requirements of Planktothrix were met. Four chemotypes were reisolated from the Oslo lake district over a period of 33–40 years, suggesting that they have been members of local Planktothrix populations for decades.
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oligopeptide chemotypes of the toxic freshwater cyanobacterium planktothrix can form sub populations with dissimilar ecological traits
Limnology and Oceanography, 2008Co-Authors: Thomas Rohrlack, Camilla Blikstad Halstvedt, Robert Ptacnik, Randi Skulberg, Hans Utkilen, Bente Edvardsen, Olav M SkulbergAbstract:Nonribosomal Oligopeptides were used as qualitative and quantitative markers to test whether populations of the toxic freshwater cyanobacterium Planktothrix comprise subpopulations with dissimilar ecological traits. A field program was conducted in Lake Steinsfjorden (Norway), where Planktothrix has dominated the phytoplankton community for decades, allowing the present study to disregard other potential producers of nonribosomal Oligopeptides. Four chemotypes with distinct cellular oligopeptide patterns were found in the lake. The chemotypes occurred largely unaltered throughout a period of up to 33 yr and differed with respect to seasonal dynamics, depth distribution, and participation in loss processes. Changes in the relative abundance of chemotypes occurred almost constantly and could not be explained with fluctuations in light, temperature, or concentration of macronutrients but might have been due to differences among chemotypes in depth regulation or interaction with grazers or pathogens. Chemotypes correlated weakly with taxonomic groups and genotypes defined on the basis of phycocyanin operon deoxyribonucleic acid (DNA) sequences. Our findings suggest that first, oligopeptide chemotypes can have dissimilar ecological traits and therefore interact differently with their environment; second, populations of toxic freshwater cyanobacteria can comprise multiple ecologically distinct subpopulations; and, third, the relative abundance of these may vary, causing a high variability in wholepopulation properties. The latter was demonstrated for the microcystin-related toxicity of Planktothrix. The consequences of the present findings for the taxonomy of Planktothrix are discussed.
Akira Tsuji - One of the best experts on this subject based on the ideXlab platform.
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tissue selective drug delivery utilizing carrier mediated transport systems
Journal of Controlled Release, 1999Co-Authors: Akira TsujiAbstract:This paper describes some successful examples of a tissue selective drug delivery by utilizing specialized transporter(s) expressed in the targeted tissue cells. These are as follows: (1) oral delivery via H + /oligopeptide transporter, rat or human Peptl, in the intestine for β-lactam antibiotics and a newly synthesized dipeptide, L-dopa-L-phenylalanine; (2) tumor cell specific delivery via the newly discovered H + /oligopeptide transporter(s) expressed in human fibrosarcoma cell line HT-1080 for model Oligopeptides, glycylsarcosine and carnosine; (3) oral and hepatic delivery via an H + /monocarboxylate transporter in the intestine and an organic anion transporter in the liver for HMG-CoA reductase inhibitor, pravastatin; and (4) lung selective delivery via some type of transporter and avoidance of transfer into the brain via P-glycoprotein at the blood-brain barrier for a new quinolone antibacterial, HSR-903.
