Archives of Environmental Contamination and Toxicology, 2008
Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects ... more Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GMmaize.
Following the fortuitous demonstration of anti-cytomegalovirus (CMV) IgM antibodies in serum samp... more Following the fortuitous demonstration of anti-cytomegalovirus (CMV) IgM antibodies in serum samples from 2 patients with acute peripheral facial palsy (APFP), a systematic study was initiated which provided serological evidence of a coincidental CMV multiplication in 72% of 65 consecutive cases with APFP. Transmission electron microscopy has revealed Herpetoviridae-like virus particles in 56% of urine samples studied. A reactivation of latent CMV at the time of palsy onset is considered the most probable explanation of these findings.
An indirect fluorescent antibody technique (IFAT) was applied to serologically confirm the clinic... more An indirect fluorescent antibody technique (IFAT) was applied to serologically confirm the clinical diagnosis in 507 nephropathia epidemica (NE) suspected patients. Hantaan virus (HV), the agent of Korean hemorrhagic fever, which is serologically related to the NE agent, was used as antigen. Both IgG and IgM reactions were detected. High levels of IgG antibodies to HV were common, even in the acute phase of illness. Over a 5-year period, a total of 35% of the NE suspected patients revealed antibodies to HV, but this varied considerably in the different years. In 2 endemic areas the serological confirmation of the NE diagnosis was 60%. 82% of the seropositive NE patients lived in 4 endemic areas. The bank vole (Clethrionomys glareolus) was common in all areas and predominant in 2. The wood mouse (Apodemus sylvaticus) was abundant in the other 2. In years with high bank vole population, the number of seropositive NE cases increased, with a peak in October/November. When the bank vole population was low, the relatively few seropositive NE cases occurred more regularly throughout the year. Subclinical infections were common. Antibodies to HV were detected in 74% male and 26% female NE patients, but the ratio varied between age groups.
Important crops like maize and soy are often genetically modified (GM) to express insecticidal pr... more Important crops like maize and soy are often genetically modified (GM) to express insecticidal proteins. MON810 maize, modified to produce insecticidal Cry1Ab protein, is assumed safe for human consumption. However, the Cry1Ab protein shares 86% sequence homology with the reported adjuvant Cry1Ac, and may therefore enhance unwanted immune responses like allergies. While many experiments focus on the allergic potential of ingested GM food, there is a relevant exposure also through inhalation of pollen and dried airborne plant material from GM crops. Here, we investigated whether plant material from Cry1Ab-expressing MON810 maize or purified Cry1Ab protein (produced in recombinant bacteria) may act as adjuvants in a mouse model of airway allergy.
Biological risk assessment of food containing recombinant DNA has exposed knowledge gaps related ... more Biological risk assessment of food containing recombinant DNA has exposed knowledge gaps related to the general fate of DNA in the gastrointestinal tract (GIT). Here, a series of experiments is presented that were designed to determine if genetic transformation of the naturally competent bacterium Acinetobacter baylyi BD413 occurs in the GIT of mice and rats, with feed-introduced bacterial DNA containing a kanamycin resistance gene (nptII). Strain BD413 was found in various gut locations in germ-free mice at 10 3 −10 5 CFU per gram GIT content 24-48 h after administration. However, subsequent DNA exposure of the colonized mice did not result in detectable bacterial transformants, with a detection limit of 1 transformant per 10 3 −10 5 bacteria. Further attempts to increase the likelihood of detection by introducing weak positive selection with kanamycin of putative transformants arising in vivo during a 4-week-long feeding experiment (where the mice received DNA and the recipient cells regularly) did not yield transformants either. Moreover, the in vitro exposure of actively growing A. baylyi cells to gut contents from the stomach, small intestine, cecum or colon contents of rats (with a normal microbiota) fed either purified DNA (50 µg) or bacterial cell lysates did not produce bacterial transformants. The presence of gut content of germfree mice was also highly inhibitory to transformation of A. baylyi, indicating that microbially-produced nucleases are not responsible for the sharp 500-to 1 000 000-fold reduction of transformation frequencies seen. Finally, a range of isolates from the genera Enterococcus, Streptococcus and Bifidobacterium spp. was examined for competence expression in vitro, without yielding any transformants. In conclusion, model choice and methodological constraints severely limit the sample size and, hence, transfer frequencies that can be measured experimentally in the GIT. Our observations suggest the contents of the GIT shield or adsorb DNA, preventing detectable exposure of feed-derived DNA fragments to competent bacteria.
The genetically modified (GM) maize event MON810 has been inserted with a processed version of th... more The genetically modified (GM) maize event MON810 has been inserted with a processed version of the transgene, cry1Ab, derived from the soil bacterium Bacillus thuringiensis (Bt) to express proteins with insecticidal properties. Such proteins may introduce new allergens and also act as adjuvants that promote allergic responses. While focus has been on safe consumption and hence the oral exposure to GM food and feed, little is known regarding inhalation of pollen and desiccated airborne plant material from GM crops. The aim of this study was to investigate whether plant material from the Cry1Ab-expressing maize variety MON810, or trypsin-activated Cry1Ab (trypCry1Ab) protein produced in recombinant bacteria, may act as adjuvants against the allergen ovalbumin (OVA) in a mouse model of airway allergy. A clear proallergic adjuvant effect of the mucosal adjuvant cholera toxin (CT) was demonstrated, determined as increased specific IgE, eosinophils and Th2 cytokines in MLN cell supernates, while no elevation in OVA-specific antibodies or cytokine release from MLN cells after stimulation with OVA were observed in mice receiving Cry1Abcontaining plant materials or the trypCry1Ab protein. Our data suggest that Cry1Ab proteins had no detectable systemic adjuvant effect in mice after airway exposure. Further experiments with purified plant proteins, as well as long-term exposures needs be conducted to further evaluate exposures experienced in reallife situations.
Page 1. The Precautionary Principle Applied to Deliberate Release of Genetically Modified Organis... more Page 1. The Precautionary Principle Applied to Deliberate Release of Genetically Modified Organisms (GMOs) ... In this paper, we intend to describe and discuss whether regulation of deliberate GMO release needs involvement of the precautionary principle. ...
Fowlpox virus (FWPV) recombinant vaccines are presently being tested as an antihuman immunodefici... more Fowlpox virus (FWPV) recombinant vaccines are presently being tested as an antihuman immunodeficiency virus vaccine for humans. However, biosafety, as well as the morphogenesis of FWPV in mammalian cells, are not well understood. Currently, electron microscopy is the method of choice for analyzing virus morphogenesis in cell lines. In this study, four different electron microscopic techniques were used to study FWPV morphogenesis in the Syrian baby hamster kidney (BHK-21) cell line: direct negative stain electron microscopy, ultrathin section transmission electron microscopy, cryoimmunoelectron microscopy, and scanning electron microscopy. The study showed matured viruses, as well as other stages of fowlpox virus maturation, in BHK-21 cells that led to productive virus multiplication. A number of virus-containing vesicles and plasma membrane-associated mature viruses at an early stage in the budding process were observed. In addition, intracellular mature virus was observed in layers of the trans-Golgi network, a characteristic of intracellular mature virus wrapping that results in the formation of intracellular enveloped virus. The size and morphology of FWPV observed in this study are comparable with previously published data. This study presents the first morphological evidence for the release of FWPV by budding in BHK-21 cells.
The ongoing controversies over genetically modified organisms (GMOs) in Europe remain intense. As... more The ongoing controversies over genetically modified organisms (GMOs) in Europe remain intense. Assessing the risks associated with new technologies is crucial, and becomes particularly important for self-replicating GMOs used in open ecosystems. In general, scientific disagreement and debate is at the core of knowledge generation. However, in the GMO debate, it seems that pre-conceived conclusions can in some cases overshadow real data and factual results of investigations. In this article, we describe how the German ban on the cultivation of MON810 Bt-transgenic maize plant has been criticized for not having a sound scientific justification and provide arguments for why we disagree with this perspective. We do this by demonstrating in detail how arguments put forward by Agnes Ricroch and colleagues in an article from Transgenic Research are based on i) serious scientific flaws, such as omitting core results and misrepresenting others; ii) inconsistency in how laboratory studies that show negative effects of GM plant exposure should be followed up; and iii) a systematic selection of particular results and/or studies that match their own arguments. We conclude that Ricroch et al. misrepresent and selectively scrutinize certain data only. The effect of this double standard is that those only reading or referring to Ricroch et al. will be seriously misinformed about our study as well as in the discussion on the 2009 German ban of the MON810 GM maize. However, we do not claim that the ban was finally and irreversibly justified by the science referred to, including our own studies within the field. The German ban on MON810 was, and must be, a political decision, guided by valid scientific evidence.
Mycorrhizal fungi are among the most common symbioses found in terrestrial ecosystems, both natur... more Mycorrhizal fungi are among the most common symbioses found in terrestrial ecosystems, both natural and managed. They are important for many reasons, but most notably because of their positive effects on plant growth, which are mediated by their uptake of nutrients from the soil and transport of these to the roots. Moreover, many edible fungi are mycorrhizal. The study of mycorrhizal fungi has been hampered by the inability to identify species and individuals in the soil. This has been greatly aided by DNA-based methods, which first require the extraction of DNA. Herein, I discuss some general concerns that must be considered when extracting and purifying DNA from ecological samples and offer specific methods for soil, mycorrhizal roots, and fruiting bodies. These methods are rapid, safe, effective, relatively inexpensive, and convenient because they are based on commercially available kits. 58 comparing macromolecules [5]
Journal of Agricultural Chemistry and Environment, 2015
Herbicide tolerant plants such as Roundup-Ready soybean contain residues of glyphosate herbicide.... more Herbicide tolerant plants such as Roundup-Ready soybean contain residues of glyphosate herbicide. These residues are considered safe and previous animal-feeding-studies have failed to find negative effects related to such chemical residues. The present study tests 8 experimental soymeal diets as feed in groups (each containing 20 individuals) of test-animals (D. magna). The diets have different levels of glyphosate residues and we show that animal growth, reproductive maturity and number of offspring are correlated with these chemicals. The tested soybeans are from ordinary agriculture in Iowa USA and the residues are below the regulatory limits. Despite this, clear negative effects are seen in life-long feeding. The work enhances the need for including analysis of herbicide residues in future assessment of GMO.
Avipoxviruses have many advantages and are being increasingly employed as recombinant vaccine vec... more Avipoxviruses have many advantages and are being increasingly employed as recombinant vaccine vectors. One attractive feature is that while inserted transgenes are expressed in immunologically favourable ways, avipoxvirus infections of mammalian cells are believed to be abortive. The experimental evidence supporting this belief is, however, based on a limited number of mammalian cell-types and a few avipoxvirus species. We evaluated two avian and eight mammalian cell lines for permissivity to three avipoxvirus strains, one reference fowlpoxvirus and two newly isolated strains from sparrow and pigeon, respectively. Both avian cell lines were, as expected, permissive for all three avipoxvirus strains. However, by multiplication assays, we found to our surprise that Syrian baby hamster kidney (BHK-21) cells were equally permissive to all virus strains. Results from electron microscopy of infected BHK-21 cells revealed viral morphogenesis proceeding to various forms of infectious viruses. These results were supported by the demonstration of avipoxvirus specific late gene expression and avipoxvirus specific DNA restriction pattern in BHK-21 infected cells.
Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia... more Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia can infect humans, cattle, felidae and other animals. Molecular characterization of CPXVs isolated from different geographic locations is important for the understanding of their biology, geographic distribution, classification and evolution. Our aim was to characterize CPXVs isolated from Fennoscandia on the basis of A-type inclusion (ATI) phenotype, restriction fragment length polymorphism (RFLP) profiles of atip gene fragment amplicon, and phylogenetic tree topology in conjunction with the patristic and genetic distances based on full length DNA sequence of the atip and p4c genes. Methods: ATI phenotypes were determined by transmission electron microcopy and RFLP profiles were obtained by restriction enzyme digestion of the atip gene fragment PCR product. A 6.2 kbp region spanning the entire atip and p4c genes of Fennoscandian CPXV isolates was amplified and sequenced. The phylogenetic affinity of Fennoscandian CPXV isolates to OPVs isolated from other geographic regions was determined on the basis of the atip and p4c genes.
Human polyomavirus BK (BKV) DNA and proteins have been detected in a number of bone tumours. We t... more Human polyomavirus BK (BKV) DNA and proteins have been detected in a number of bone tumours. We therefore investigated whether BKV infection might initiate transformation of human anchorage-dependent osteosarcoma cells in vitro. Infection of the osteosarcoma cell line U-2OS with a naturally occurring BKV strain resulted in soft agarose competent cell clones. In a subclone, designated U-2OS15E, approximately 10 Á/20% of the cells contained episomal BKV genomes. A corresponding proportion of cells expressed BKV proteins and produced viral progeny. This proportion was not increased by BKV superinfection. Furthermore, U-2OS15E cells were resistant to SV40 infection. The transformed status of U-2OS15E cells lasted only for a few passages. However, the persistently infected cells produced infectious virions for more than 300 generations. In addition to representing a model system for persistent BKV infection, the uninfected and persistently BKV-infected cell cultures are useful tools for control and calibration of in situ BKV nucleic acid and protein detection methods. #
The human polyomavirus BK (BKV) has a proven oncogenic potential, but its contribution to tumorig... more The human polyomavirus BK (BKV) has a proven oncogenic potential, but its contribution to tumorigenesis under natural conditions remains undetermined. As for other primate polyomaviruses, the approximately 5.2 kbp double-stranded circular genome of BKV has three functional regions: the coding regions for the two early (T, t antigens) and four late (agno, capsid proteins; VPI-3) genes separated by a noncoding control region (NCCR). The NCCR contains the origin of replication as well as a promoter/enhancer with a mosaic of cis-acting elements involved in the regulation of both early and late transcription. Since the original isolation of BKV in 1971, a number of other strains have been identified. Most strains reveal a strong sequence conservation in the protein coding regions of the genome, while the NCCR exhibits considerable variation between different BKV isolates. This variation is due to deletions, duplications, and rearrangements of a basic set of sequence blocks. Comparative studies have proven that the anatomy of the NCCR may determine the transcriptional activities governed by the promoter/enhancer, the host cell tropism and permissivity, as well as the oncogenic potential of a given BKV strain. In most cases, however, the NCCR sequence of new isolates was determined after the virus had been passaged several times in more or less arbitrarily chosen cell cultures, a process known to predispose for NCCR rearrangements. Following the development of the polymerase chain reaction (PCR), it has become feasible to obtain naturally occurring BKV NCCRs, and their sequences, in samples taken directly from infected human individuals. Hence, the biological significance of BKV NCCR variation may be studied without prior propagation of the virus in cell culture. Such variation has general interest, because the BKV NCCRs represent typical mammalian promoter/enhancers, with a large number of binding motifs for cellular transacting factors, which can be conveniently handled for experimental purposes. This communication reviews the naturally occurring BKV NCCR variants, isolated and sequenced directly from human samples, that have been reported so far. The sequences of the different NCCRs are compared and analyzed for the presence of proven and putative cellular transcription factor binding sites. Differences in biological properties between BKV variants are discussed in light of their aberrant NCCR anatomies and the potentially modifying influence of transacting factors.
Archives of Environmental Contamination and Toxicology, 2008
Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects ... more Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GMmaize.
Following the fortuitous demonstration of anti-cytomegalovirus (CMV) IgM antibodies in serum samp... more Following the fortuitous demonstration of anti-cytomegalovirus (CMV) IgM antibodies in serum samples from 2 patients with acute peripheral facial palsy (APFP), a systematic study was initiated which provided serological evidence of a coincidental CMV multiplication in 72% of 65 consecutive cases with APFP. Transmission electron microscopy has revealed Herpetoviridae-like virus particles in 56% of urine samples studied. A reactivation of latent CMV at the time of palsy onset is considered the most probable explanation of these findings.
An indirect fluorescent antibody technique (IFAT) was applied to serologically confirm the clinic... more An indirect fluorescent antibody technique (IFAT) was applied to serologically confirm the clinical diagnosis in 507 nephropathia epidemica (NE) suspected patients. Hantaan virus (HV), the agent of Korean hemorrhagic fever, which is serologically related to the NE agent, was used as antigen. Both IgG and IgM reactions were detected. High levels of IgG antibodies to HV were common, even in the acute phase of illness. Over a 5-year period, a total of 35% of the NE suspected patients revealed antibodies to HV, but this varied considerably in the different years. In 2 endemic areas the serological confirmation of the NE diagnosis was 60%. 82% of the seropositive NE patients lived in 4 endemic areas. The bank vole (Clethrionomys glareolus) was common in all areas and predominant in 2. The wood mouse (Apodemus sylvaticus) was abundant in the other 2. In years with high bank vole population, the number of seropositive NE cases increased, with a peak in October/November. When the bank vole population was low, the relatively few seropositive NE cases occurred more regularly throughout the year. Subclinical infections were common. Antibodies to HV were detected in 74% male and 26% female NE patients, but the ratio varied between age groups.
Important crops like maize and soy are often genetically modified (GM) to express insecticidal pr... more Important crops like maize and soy are often genetically modified (GM) to express insecticidal proteins. MON810 maize, modified to produce insecticidal Cry1Ab protein, is assumed safe for human consumption. However, the Cry1Ab protein shares 86% sequence homology with the reported adjuvant Cry1Ac, and may therefore enhance unwanted immune responses like allergies. While many experiments focus on the allergic potential of ingested GM food, there is a relevant exposure also through inhalation of pollen and dried airborne plant material from GM crops. Here, we investigated whether plant material from Cry1Ab-expressing MON810 maize or purified Cry1Ab protein (produced in recombinant bacteria) may act as adjuvants in a mouse model of airway allergy.
Biological risk assessment of food containing recombinant DNA has exposed knowledge gaps related ... more Biological risk assessment of food containing recombinant DNA has exposed knowledge gaps related to the general fate of DNA in the gastrointestinal tract (GIT). Here, a series of experiments is presented that were designed to determine if genetic transformation of the naturally competent bacterium Acinetobacter baylyi BD413 occurs in the GIT of mice and rats, with feed-introduced bacterial DNA containing a kanamycin resistance gene (nptII). Strain BD413 was found in various gut locations in germ-free mice at 10 3 −10 5 CFU per gram GIT content 24-48 h after administration. However, subsequent DNA exposure of the colonized mice did not result in detectable bacterial transformants, with a detection limit of 1 transformant per 10 3 −10 5 bacteria. Further attempts to increase the likelihood of detection by introducing weak positive selection with kanamycin of putative transformants arising in vivo during a 4-week-long feeding experiment (where the mice received DNA and the recipient cells regularly) did not yield transformants either. Moreover, the in vitro exposure of actively growing A. baylyi cells to gut contents from the stomach, small intestine, cecum or colon contents of rats (with a normal microbiota) fed either purified DNA (50 µg) or bacterial cell lysates did not produce bacterial transformants. The presence of gut content of germfree mice was also highly inhibitory to transformation of A. baylyi, indicating that microbially-produced nucleases are not responsible for the sharp 500-to 1 000 000-fold reduction of transformation frequencies seen. Finally, a range of isolates from the genera Enterococcus, Streptococcus and Bifidobacterium spp. was examined for competence expression in vitro, without yielding any transformants. In conclusion, model choice and methodological constraints severely limit the sample size and, hence, transfer frequencies that can be measured experimentally in the GIT. Our observations suggest the contents of the GIT shield or adsorb DNA, preventing detectable exposure of feed-derived DNA fragments to competent bacteria.
The genetically modified (GM) maize event MON810 has been inserted with a processed version of th... more The genetically modified (GM) maize event MON810 has been inserted with a processed version of the transgene, cry1Ab, derived from the soil bacterium Bacillus thuringiensis (Bt) to express proteins with insecticidal properties. Such proteins may introduce new allergens and also act as adjuvants that promote allergic responses. While focus has been on safe consumption and hence the oral exposure to GM food and feed, little is known regarding inhalation of pollen and desiccated airborne plant material from GM crops. The aim of this study was to investigate whether plant material from the Cry1Ab-expressing maize variety MON810, or trypsin-activated Cry1Ab (trypCry1Ab) protein produced in recombinant bacteria, may act as adjuvants against the allergen ovalbumin (OVA) in a mouse model of airway allergy. A clear proallergic adjuvant effect of the mucosal adjuvant cholera toxin (CT) was demonstrated, determined as increased specific IgE, eosinophils and Th2 cytokines in MLN cell supernates, while no elevation in OVA-specific antibodies or cytokine release from MLN cells after stimulation with OVA were observed in mice receiving Cry1Abcontaining plant materials or the trypCry1Ab protein. Our data suggest that Cry1Ab proteins had no detectable systemic adjuvant effect in mice after airway exposure. Further experiments with purified plant proteins, as well as long-term exposures needs be conducted to further evaluate exposures experienced in reallife situations.
Page 1. The Precautionary Principle Applied to Deliberate Release of Genetically Modified Organis... more Page 1. The Precautionary Principle Applied to Deliberate Release of Genetically Modified Organisms (GMOs) ... In this paper, we intend to describe and discuss whether regulation of deliberate GMO release needs involvement of the precautionary principle. ...
Fowlpox virus (FWPV) recombinant vaccines are presently being tested as an antihuman immunodefici... more Fowlpox virus (FWPV) recombinant vaccines are presently being tested as an antihuman immunodeficiency virus vaccine for humans. However, biosafety, as well as the morphogenesis of FWPV in mammalian cells, are not well understood. Currently, electron microscopy is the method of choice for analyzing virus morphogenesis in cell lines. In this study, four different electron microscopic techniques were used to study FWPV morphogenesis in the Syrian baby hamster kidney (BHK-21) cell line: direct negative stain electron microscopy, ultrathin section transmission electron microscopy, cryoimmunoelectron microscopy, and scanning electron microscopy. The study showed matured viruses, as well as other stages of fowlpox virus maturation, in BHK-21 cells that led to productive virus multiplication. A number of virus-containing vesicles and plasma membrane-associated mature viruses at an early stage in the budding process were observed. In addition, intracellular mature virus was observed in layers of the trans-Golgi network, a characteristic of intracellular mature virus wrapping that results in the formation of intracellular enveloped virus. The size and morphology of FWPV observed in this study are comparable with previously published data. This study presents the first morphological evidence for the release of FWPV by budding in BHK-21 cells.
The ongoing controversies over genetically modified organisms (GMOs) in Europe remain intense. As... more The ongoing controversies over genetically modified organisms (GMOs) in Europe remain intense. Assessing the risks associated with new technologies is crucial, and becomes particularly important for self-replicating GMOs used in open ecosystems. In general, scientific disagreement and debate is at the core of knowledge generation. However, in the GMO debate, it seems that pre-conceived conclusions can in some cases overshadow real data and factual results of investigations. In this article, we describe how the German ban on the cultivation of MON810 Bt-transgenic maize plant has been criticized for not having a sound scientific justification and provide arguments for why we disagree with this perspective. We do this by demonstrating in detail how arguments put forward by Agnes Ricroch and colleagues in an article from Transgenic Research are based on i) serious scientific flaws, such as omitting core results and misrepresenting others; ii) inconsistency in how laboratory studies that show negative effects of GM plant exposure should be followed up; and iii) a systematic selection of particular results and/or studies that match their own arguments. We conclude that Ricroch et al. misrepresent and selectively scrutinize certain data only. The effect of this double standard is that those only reading or referring to Ricroch et al. will be seriously misinformed about our study as well as in the discussion on the 2009 German ban of the MON810 GM maize. However, we do not claim that the ban was finally and irreversibly justified by the science referred to, including our own studies within the field. The German ban on MON810 was, and must be, a political decision, guided by valid scientific evidence.
Mycorrhizal fungi are among the most common symbioses found in terrestrial ecosystems, both natur... more Mycorrhizal fungi are among the most common symbioses found in terrestrial ecosystems, both natural and managed. They are important for many reasons, but most notably because of their positive effects on plant growth, which are mediated by their uptake of nutrients from the soil and transport of these to the roots. Moreover, many edible fungi are mycorrhizal. The study of mycorrhizal fungi has been hampered by the inability to identify species and individuals in the soil. This has been greatly aided by DNA-based methods, which first require the extraction of DNA. Herein, I discuss some general concerns that must be considered when extracting and purifying DNA from ecological samples and offer specific methods for soil, mycorrhizal roots, and fruiting bodies. These methods are rapid, safe, effective, relatively inexpensive, and convenient because they are based on commercially available kits. 58 comparing macromolecules [5]
Journal of Agricultural Chemistry and Environment, 2015
Herbicide tolerant plants such as Roundup-Ready soybean contain residues of glyphosate herbicide.... more Herbicide tolerant plants such as Roundup-Ready soybean contain residues of glyphosate herbicide. These residues are considered safe and previous animal-feeding-studies have failed to find negative effects related to such chemical residues. The present study tests 8 experimental soymeal diets as feed in groups (each containing 20 individuals) of test-animals (D. magna). The diets have different levels of glyphosate residues and we show that animal growth, reproductive maturity and number of offspring are correlated with these chemicals. The tested soybeans are from ordinary agriculture in Iowa USA and the residues are below the regulatory limits. Despite this, clear negative effects are seen in life-long feeding. The work enhances the need for including analysis of herbicide residues in future assessment of GMO.
Avipoxviruses have many advantages and are being increasingly employed as recombinant vaccine vec... more Avipoxviruses have many advantages and are being increasingly employed as recombinant vaccine vectors. One attractive feature is that while inserted transgenes are expressed in immunologically favourable ways, avipoxvirus infections of mammalian cells are believed to be abortive. The experimental evidence supporting this belief is, however, based on a limited number of mammalian cell-types and a few avipoxvirus species. We evaluated two avian and eight mammalian cell lines for permissivity to three avipoxvirus strains, one reference fowlpoxvirus and two newly isolated strains from sparrow and pigeon, respectively. Both avian cell lines were, as expected, permissive for all three avipoxvirus strains. However, by multiplication assays, we found to our surprise that Syrian baby hamster kidney (BHK-21) cells were equally permissive to all virus strains. Results from electron microscopy of infected BHK-21 cells revealed viral morphogenesis proceeding to various forms of infectious viruses. These results were supported by the demonstration of avipoxvirus specific late gene expression and avipoxvirus specific DNA restriction pattern in BHK-21 infected cells.
Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia... more Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia can infect humans, cattle, felidae and other animals. Molecular characterization of CPXVs isolated from different geographic locations is important for the understanding of their biology, geographic distribution, classification and evolution. Our aim was to characterize CPXVs isolated from Fennoscandia on the basis of A-type inclusion (ATI) phenotype, restriction fragment length polymorphism (RFLP) profiles of atip gene fragment amplicon, and phylogenetic tree topology in conjunction with the patristic and genetic distances based on full length DNA sequence of the atip and p4c genes. Methods: ATI phenotypes were determined by transmission electron microcopy and RFLP profiles were obtained by restriction enzyme digestion of the atip gene fragment PCR product. A 6.2 kbp region spanning the entire atip and p4c genes of Fennoscandian CPXV isolates was amplified and sequenced. The phylogenetic affinity of Fennoscandian CPXV isolates to OPVs isolated from other geographic regions was determined on the basis of the atip and p4c genes.
Human polyomavirus BK (BKV) DNA and proteins have been detected in a number of bone tumours. We t... more Human polyomavirus BK (BKV) DNA and proteins have been detected in a number of bone tumours. We therefore investigated whether BKV infection might initiate transformation of human anchorage-dependent osteosarcoma cells in vitro. Infection of the osteosarcoma cell line U-2OS with a naturally occurring BKV strain resulted in soft agarose competent cell clones. In a subclone, designated U-2OS15E, approximately 10 Á/20% of the cells contained episomal BKV genomes. A corresponding proportion of cells expressed BKV proteins and produced viral progeny. This proportion was not increased by BKV superinfection. Furthermore, U-2OS15E cells were resistant to SV40 infection. The transformed status of U-2OS15E cells lasted only for a few passages. However, the persistently infected cells produced infectious virions for more than 300 generations. In addition to representing a model system for persistent BKV infection, the uninfected and persistently BKV-infected cell cultures are useful tools for control and calibration of in situ BKV nucleic acid and protein detection methods. #
The human polyomavirus BK (BKV) has a proven oncogenic potential, but its contribution to tumorig... more The human polyomavirus BK (BKV) has a proven oncogenic potential, but its contribution to tumorigenesis under natural conditions remains undetermined. As for other primate polyomaviruses, the approximately 5.2 kbp double-stranded circular genome of BKV has three functional regions: the coding regions for the two early (T, t antigens) and four late (agno, capsid proteins; VPI-3) genes separated by a noncoding control region (NCCR). The NCCR contains the origin of replication as well as a promoter/enhancer with a mosaic of cis-acting elements involved in the regulation of both early and late transcription. Since the original isolation of BKV in 1971, a number of other strains have been identified. Most strains reveal a strong sequence conservation in the protein coding regions of the genome, while the NCCR exhibits considerable variation between different BKV isolates. This variation is due to deletions, duplications, and rearrangements of a basic set of sequence blocks. Comparative studies have proven that the anatomy of the NCCR may determine the transcriptional activities governed by the promoter/enhancer, the host cell tropism and permissivity, as well as the oncogenic potential of a given BKV strain. In most cases, however, the NCCR sequence of new isolates was determined after the virus had been passaged several times in more or less arbitrarily chosen cell cultures, a process known to predispose for NCCR rearrangements. Following the development of the polymerase chain reaction (PCR), it has become feasible to obtain naturally occurring BKV NCCRs, and their sequences, in samples taken directly from infected human individuals. Hence, the biological significance of BKV NCCR variation may be studied without prior propagation of the virus in cell culture. Such variation has general interest, because the BKV NCCRs represent typical mammalian promoter/enhancers, with a large number of binding motifs for cellular transacting factors, which can be conveniently handled for experimental purposes. This communication reviews the naturally occurring BKV NCCR variants, isolated and sequenced directly from human samples, that have been reported so far. The sequences of the different NCCRs are compared and analyzed for the presence of proven and putative cellular transcription factor binding sites. Differences in biological properties between BKV variants are discussed in light of their aberrant NCCR anatomies and the potentially modifying influence of transacting factors.
Uploads
Papers by Terje Traavik