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Mirlean N, Calliari L, Johannesson K. Dredging in an estuary causes contamination by fluid mud on a tourist ocean beach. Evidence via REE ratios. Mar Pollut Bull 2020; 159:111495. [PMID: 32892925 DOI: 10.1016/j.marpolbul.2020.111495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/13/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023]
Abstract
Deposits of fluid mud on wave-dominated beaches are rare. Where they happen frequently and periodically, they can be associated with anthropic processes that bring fluid mud to the shoreface and surf zone. To determine the reason for the frequent deposition of fluid mud at Cassino Beach (Southern Brazil) in the 2014-2020 period, the La/Eu and Gd/Yb ratios in marine, beach, and adjacent Patos estuary sediments were investigated. Mud from the beach showed similar ratios of REE to dredged sediments from the harbor basin and navigation channel within the estuary. Industrial and port activity changes REE ratio in sediments of the navigation channel, and they are distinct from naturally deposited marine and estuarine sediments. We conclude that the mud deposition events at the beach are most likely associated with dredging processes in the estuary especially where overflow is the source of fluid mud on the beach shoreface.
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Affiliation(s)
- N Mirlean
- Oceanography Institute, Federal University of Rio Grande (FURG), Rio Grande 96203-900, Brazil.
| | - L Calliari
- Oceanography Institute, Federal University of Rio Grande (FURG), Rio Grande 96203-900, Brazil
| | - K Johannesson
- School for the Environment, University of Massachusetts Boston, Boston, MA 02125-3393, USA
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2
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Rafajlović M, Kleinhans D, Gulliksson C, Fries J, Johansson D, Ardehed A, Sundqvist L, Pereyra RT, Mehlig B, Jonsson PR, Johannesson K. Neutral processes forming large clones during colonization of new areas. J Evol Biol 2017; 30:1544-1560. [PMID: 28557006 DOI: 10.1111/jeb.13124] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 04/28/2017] [Accepted: 05/24/2017] [Indexed: 01/16/2023]
Abstract
In species reproducing both sexually and asexually clones are often more common in recently established populations. Earlier studies have suggested that this pattern arises due to natural selection favouring generally or locally successful genotypes in new environments. Alternatively, as we show here, this pattern may result from neutral processes during species' range expansions. We model a dioecious species expanding into a new area in which all individuals are capable of both sexual and asexual reproduction, and all individuals have equal survival rates and dispersal distances. Even under conditions that favour sexual recruitment in the long run, colonization starts with an asexual wave. After colonization is completed, a sexual wave erodes clonal dominance. If individuals reproduce more than one season, and with only local dispersal, a few large clones typically dominate for thousands of reproductive seasons. Adding occasional long-distance dispersal, more dominant clones emerge, but they persist for a shorter period of time. The general mechanism involved is simple: edge effects at the expansion front favour asexual (uniparental) recruitment where potential mates are rare. Specifically, our model shows that neutral processes (with respect to genotype fitness) during the population expansion, such as random dispersal and demographic stochasticity, produce genotype patterns that differ from the patterns arising in a selection model. The comparison with empirical data from a post-glacially established seaweed species (Fucus radicans) shows that in this case, a neutral mechanism is strongly supported.
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Affiliation(s)
- M Rafajlović
- Department of Physics, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - D Kleinhans
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - C Gulliksson
- Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - J Fries
- Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - D Johansson
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Biological and Environmental Sciences, University of Gothenburg, Tjärnö, Strömstad, Sweden
| | - A Ardehed
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Biological and Environmental Sciences, University of Gothenburg, Tjärnö, Strömstad, Sweden
| | - L Sundqvist
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - R T Pereyra
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Tjärnö, Strömstad, Sweden
| | - B Mehlig
- Department of Physics, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - P R Jonsson
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Tjärnö, Strömstad, Sweden
| | - K Johannesson
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Tjärnö, Strömstad, Sweden
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3
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Johannesson K, Butlin RK. What explains rare and conspicuous colours in a snail? A test of time-series data against models of drift, migration or selection. Heredity (Edinb) 2016; 118:21-30. [PMID: 27649616 PMCID: PMC5176118 DOI: 10.1038/hdy.2016.77] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/24/2016] [Accepted: 07/26/2016] [Indexed: 12/24/2022] Open
Abstract
It is intriguing that conspicuous colour morphs of a prey species may be maintained at low frequencies alongside cryptic morphs. Negative frequency-dependent selection by predators using search images ('apostatic selection') is often suggested without rejecting alternative explanations. Using a maximum likelihood approach we fitted predictions from models of genetic drift, migration, constant selection, heterozygote advantage or negative frequency-dependent selection to time-series data of colour frequencies in isolated populations of a marine snail (Littorina saxatilis), re-established with perturbed colour morph frequencies and followed for >20 generations. Snails of conspicuous colours (white, red, banded) are naturally rare in the study area (usually <10%) but frequencies were manipulated to levels of ~50% (one colour per population) in 8 populations at the start of the experiment in 1992. In 2013, frequencies had declined to ~15-45%. Drift alone could not explain these changes. Migration could not be rejected in any population, but required rates much higher than those recorded. Directional selection was rejected in three populations in favour of balancing selection. Heterozygote advantage and negative frequency-dependent selection could not be distinguished statistically, although overall the results favoured the latter. Populations varied idiosyncratically as mild or variable colour selection (3-11%) interacted with demographic stochasticity, and the overall conclusion was that multiple mechanisms may contribute to maintaining the polymorphisms.
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Affiliation(s)
- K Johannesson
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden.,Centre for Marine Evolutionary Biology, University of Gothenburg, Strömstad, Sweden
| | - R K Butlin
- Centre for Marine Evolutionary Biology, University of Gothenburg, Strömstad, Sweden.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Stellenbosch Institute for Advanced Studies (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, South Africa
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4
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Wahlberg Å, Andreen Sachs M, Johannesson K, Hallberg G, Jonsson M, Skoog Svanberg A, Högberg U. Post-traumatic stress symptoms in Swedish obstetricians and midwives after severe obstetric events: a cross-sectional retrospective survey. BJOG 2016; 124:1264-1271. [PMID: 27562912 DOI: 10.1111/1471-0528.14259] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine post-traumatic stress reactions among obstetricians and midwives, experiences of support and professional consequences after severe events in the labour ward. DESIGN Cross-sectional online survey from January 7 to March 10, 2014. POPULATION Members of the Swedish Society of Obstetrics and Gynaecology and the Swedish Association of Midwives. METHODS Potentially traumatic events were defined as: the child died or was severely injured during delivery; maternal near-miss; maternal mortality; and other events such as violence or threat. The validated Screen Questionnaire Posttraumatic Stress Disorder (SQ-PTSD), based on DSM-IV (1994) 4th edition, was used to assess partial post-traumatic stress disorder (PTSD) and probable PTSD. MAIN OUTCOME MEASURES Partial or probable PTSD. RESULTS The response rate was 47% for obstetricians (n = 706) and 40% (n = 1459) for midwives. Eighty-four percent of the obstetricians and 71% of the midwives reported experiencing at least one severe event on the delivery ward. Fifteen percent of both professions reported symptoms indicative of partial PTSD, whereas 7% of the obstetricians and 5% of the midwives indicated symptoms fulfilling PTSD criteria. Having experienced emotions of guilt or perceived insufficient support from friends predicted a higher risk of suffering from partial or probable PTSD. Obstetricians and midwives with partial PTSD symptoms chose to change their work to outpatient care significantly more often than colleagues without these symptoms. CONCLUSIONS A substantial proportion of obstetricians and midwives reported symptoms of partial or probable PTSD after severe traumatic events experienced on the labour ward. Support and resilience training could avoid suffering and consequences for professional carers. TWEETABLE ABSTRACT In a survey 15% of Swedish obstetricians and midwives reported PTSD symptoms after their worst obstetric event.
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Affiliation(s)
- Å Wahlberg
- Department of Women's and Children's Health/Obstetrics & Gynaecology, Uppsala University, Uppsala, Sweden.,Department of Gynaecology and Obstetrics, Skåne University Hospital, Malmö, Sweden
| | - M Andreen Sachs
- LIME/Medical Management Centre, Karolinska Institutet, Stockholm, Sweden
| | - K Johannesson
- Neuroscience/Psychiatry, Uppsala University, Uppsala, Sweden
| | - G Hallberg
- Department of Women's and Children's Health/Obstetrics & Gynaecology, Uppsala University, Uppsala, Sweden.,Department of Gynaecology and Obstetrics, Akademiska Hospital, Uppsala, Sweden
| | - M Jonsson
- Department of Women's and Children's Health/Obstetrics & Gynaecology, Uppsala University, Uppsala, Sweden.,Department of Gynaecology and Obstetrics, Akademiska Hospital, Uppsala, Sweden
| | - A Skoog Svanberg
- Department of Women's and Children's Health/Obstetrics & Gynaecology, Uppsala University, Uppsala, Sweden
| | - U Högberg
- Department of Women's and Children's Health/Obstetrics & Gynaecology, Uppsala University, Uppsala, Sweden
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5
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Sankar MS, Vega MA, Defoe PP, Kibria MG, Ford S, Telfeyan K, Neal A, Mohajerin TJ, Hettiarachchi GM, Barua S, Hobson C, Johannesson K, Datta S. Elevated arsenic and manganese in groundwaters of Murshidabad, West Bengal, India. Sci Total Environ 2014; 488-489:570-9. [PMID: 24694939 DOI: 10.1016/j.scitotenv.2014.02.077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 02/14/2014] [Accepted: 02/14/2014] [Indexed: 05/02/2023]
Abstract
High levels of geogenic arsenic (As) and manganese (Mn) in drinking water has led to widespread health problems for the population of West Bengal, India. Here we delineate the extent of occurrences of As and Mn in Murshidabad, where the contaminated aquifers occur at shallow depths between 35 and 40 m and where access to safe drinking water is a critical issue for the local population. A total of 78 well-water samples were taken in 4 blocks on either side of the river Bhagirathi: Nabagram and Kandi (west, Pleistocene sediments), Hariharpara and Beldanga (east, Holocene sediments). High As, total iron (FeT) and low Mn concentrations were found in waters from the Holocene gray sediment aquifers east of the river Bhagirathi, while the opposite was found in the Pleistocene reddish-brown aquifer west of the river Bhagirathi in Murshidabad. Speciation of As in water samples from Holocene sediments revealed the dominant species to be As(III), with ratios of As(III):AsT ranging from 0.55 to 0.98 (average 0.74). There were indications from saturation index estimations that Mn solubility is limited by the precipitation of MnCO3. Tubewells from high As areas in proximity to anthropogenic waste influx sources showing high molar Cl/Br ratios, low SO4(2-) and low NO3(-) demonstrate relatively lower As concentrations, thereby reducing As pollution in those wells. Analyses of core samples (2 in each of the blocks) drilled to a depth of 45 m indicate that there is no significant variation in bulk As (5-20mg/kg) between the Holocene and Pleistocene sediments, indicating that favorable subsurface redox conditions conducive to mobilization are responsible for the release of As. The same applies to Mn, but concentrations vary more widely (20-2000 mg/kg). Sequential extraction of Holocene sediments showed As to be associated with 'specifically sorbed-phosphate-extractable' phases (10-15%) and with 'amorphous and well crystalline Fe-oxyhydroxide' phases (around 37%) at As-contaminated well depths, suggesting that the main As release mechanisms could be either competitive ion exchange with PO4(3-), or the dissolution of Fe oxyhydroxides. In the Pleistocene sediments Mn is predominantly found in the easily exchangeable fraction.
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Affiliation(s)
- M S Sankar
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - M A Vega
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - P P Defoe
- Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
| | - M G Kibria
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - S Ford
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - K Telfeyan
- Department of Earth and Environmental Sciences, Tulane University, New Orleans 70118, USA
| | - A Neal
- Virginia Water Resources Research Center, Virginia Tech, VA 24061, USA
| | - T J Mohajerin
- Department of Earth and Environmental Sciences, Tulane University, New Orleans 70118, USA
| | - G M Hettiarachchi
- Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
| | - S Barua
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - C Hobson
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA
| | - K Johannesson
- Department of Earth and Environmental Sciences, Tulane University, New Orleans 70118, USA
| | - S Datta
- Department of Geology, Kansas State University, Manhattan, KS 66506, USA.
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6
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Pereyra RT, Huenchuñir C, Johansson D, Forslund H, Kautsky L, Jonsson PR, Johannesson K. Parallel speciation or long-distance dispersal? Lessons from seaweeds (Fucus) in the Baltic Sea. J Evol Biol 2013; 26:1727-37. [PMID: 23859364 DOI: 10.1111/jeb.12170] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/04/2013] [Accepted: 03/28/2013] [Indexed: 11/30/2022]
Abstract
Parallel evolution has been invoked as a forceful mechanism of ecotype and species formation in many animal taxa. However, parallelism may be difficult to separate from recently monophyletically diverged species that are likely to show complex genetic relationships as a result of considerable shared ancestral variation and secondary hybridization in local areas. Thus, species' degrees of reproductive isolation, barriers to dispersal and, in particular, limited capacities for long-distance dispersal will affect demographical structures underlying mechanisms of divergent evolution. Here, we used nine microsatellite DNA markers to study intra- and interspecific genetic diversity of two recently diverged species of brown macroalgae, Fucus radicans (L. Bergström & L. Kautsky) and F. vesiculosus (Linnaeus), in the Baltic Sea. We further performed biophysical modelling to identify likely connectivity patterns influencing the species' genetic structures. For each species, we found intraspecific contrasting patterns of clonality incidence and population structure. In addition, strong genetic differentiation between the two species within each locality supported the existence of two distinct evolutionary lineages (FST = 0.15-0.41). However, overall genetic clustering analyses across both species' populations revealed that all populations from one region (Estonia) were more genetically similar to each other than to their own taxon from the other two regions (Sweden and Finland). Our data support a hypothesis of parallel speciation. Alternatively, Estonia may be the ancestral source of both species, but is presently isolated by oceanographic barriers to dispersal. Thus, a limited gene flow in combination with genetic drift could have shaped the seemingly parallel structure.
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Affiliation(s)
- R T Pereyra
- Department of Biological and Environmental Sciences - Tjärnö, University of Gothenburg, Strömstad, Sweden.
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Nylund GM, Pereyra RT, Wood HL, Johannesson K, Pavia H. Increased resistance towards generalist herbivory in the new range of a habitat-forming seaweed. Ecosphere 2012. [DOI: 10.1890/es12-00203.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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8
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Kemppainen P, Panova M, Hollander J, Johannesson K. Complete lack of mitochondrial divergence between two species of NE Atlantic marine intertidal gastropods. J Evol Biol 2009; 22:2000-11. [PMID: 19678865 DOI: 10.1111/j.1420-9101.2009.01810.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Some mitochondrial introgression is common between closely related species, but distinct species rarely show substantial introgression in their entire distribution range. In this study, however, we report a complete lack of mitochondrial divergence between two sympatric species of flat periwinkles (Littorina fabalis and Littorina obtusata) which, based on previous allozyme studies, diverged approximately 1 Ma. We re-examined their species status using both morphology (morphometric analysis) and neutral genetic markers (microsatellites) and our results confirmed that these species are well separated. Despite this, the two species shared all common cytochrome-b haplotypes throughout their NE Atlantic distribution and no deep split between typical L. fabalis and L. obtusata haplotypes could be found. We suggest that incomplete lineage sorting explains most of the lack of mitochondrial divergence between these species. However, coalescent-based analyses and the sympatric sharing of unique haplotypes suggest that introgressive hybridization also has occurred.
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Affiliation(s)
- P Kemppainen
- Department of Marine Ecology-Tjärnö, Göteborg University, SE-45296, Strömstad, Sweden.
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10
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Abstract
In organisms encountering predictable environments, fixed development is expected, whereas in organisms that cannot predict their future environment, phenotypic plasticity would be optimal to increase local adaptation. To test this prediction we experimentally compared phenotypic plasticity in two rocky-shore snail species; Littorina saxatilis releasing miniature snails on the shore, and Littorina littorea releasing drifting larvae settling on various shores, expecting L. littorea to show more phenotypic plasticity than L. saxatilis. We compared magnitude and direction of vectors of phenotypic difference in juvenile shell traits after 3 months exposure to different stimuli simulating sheltered and crab-rich shores, or wave-exposed and crab-free shores. Both species showed similar direction and magnitude of vectors of phenotypic difference with minor differences only between ecotypes of the nondispersing species, indicating that plasticity is an evolving trait in L. saxatilis. The lack of a strong plastic response in L. littorea might be explained by limits rather than costs to plasticity.
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Affiliation(s)
- J Hollander
- Department of Marine Ecology, Tjärnö Marine Biological Laboratory, Göteborg University, Stromstad, Sweden.
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Abstract
The evolution of reproductive isolation in the presence of gene flow is supported by theoretical models but rarely by data. Empirical support might be gained from studies of parallel hybrid zones between interbreeding taxa. We analysed gene flow over two hybrid zones separating ecotypes of Littorina saxatilis to test the expectation that neutral genetic markers will show site-specific differences if barriers have evolved in situ. Distinct ecotypes found in contrasting shore habitats are separated by divergent selection and poor dispersal, but hybrid zones appear between them. Swedish islands formed by postglacial uplift 5000 years ago provide opportunities to assess genetic structure in a recently evolved system. Each island houses a discrete population containing subpopulations of different ecotypes. Hybrid zones between ecotypes may be a product of ecological divergence occurring on each island or a consequence of secondary overlap of ecotypes of allopatric origin that have spread among the islands. We used six microsatellite loci to assess gene flow and genetic profiles of hybrid zones on two islands. We found reduced gene flow over both hybrid zones, indicating the presence of local reproductive barriers between ecotypes. Nevertheless, subpopulations of different ecotypes from the same island were genetically more similar to each other than were subpopulations of the same ecotype from different islands. Moreover, neutral genetic traits separating the two ecotypes across hybrid zones were site-specific. This supports a scenario of in situ origin of ecotypes by ecological divergence and nonallopatric evolution of reproductive barriers.
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Affiliation(s)
- M Panova
- Department of Marine Ecology, Göteborg University, Tjärnö Marine Biological Laboratory, Strömstad, SE-452 96, Sweden.
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12
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Mirastschijski U, Johannesson K, Jeppsson B, Agren MS. Effect of a matrix metalloproteinase activity and TNF-alpha converting enzyme inhibitor on intra-abdominal adhesions. Eur Surg Res 2005; 37:68-75. [PMID: 15818044 DOI: 10.1159/000083150] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 09/13/2004] [Indexed: 12/12/2022]
Abstract
BACKGROUND Formation of intra-abdominal adhesions depends, in part, on the activity of serine proteinases. Matrix metalloproteinases (MMP) are required for epithelialization of skin wounds but their involvement in mesothelialization of peritoneal wounds and in adhesion pathogenesis is not known. Early tumor necrosis factor-alpha (TNF-alpha) levels have been proposed to reflect propensity to adhesion formation. OBJECTIVE The impact of MMP activity and secreted TNF-alpha on peritoneal adhesion formation and healing was investigated through systemic administration of the synthetic broad-spectrum MMP and TNF-alpha-converting enzyme (TACE) inhibitor GM 6001. METHODS Female Sprague-Dawley rats of 4-6 weeks of age were injected subcutaneously daily with GM 6001 100 mg/kg (n = 12) or vehicle (n = 10) starting two days before surgery. In each rat, two standardized peritoneal wounds, 20 mm x 5 mm, were made. One peritoneal wound was sutured whereas the contralateral wound healed by secondary intention. Adhesion formation and peritoneal healing, cell proliferation, and hydroxyproline concentrations were evaluated on postoperative day 7. RESULTS Total serum TNF-alpha levels increased in vehicle-treated rats (p = 0.019) while GM 6001 treatment effectively prevented the rise in the postoperative phase (p < 0.001). No significant differences were observed in the extent of adhesion formation (p = 0.67) between control (65.0%) and GM 6001-treated (61.5%) animals, or peritoneal wound healing or cell proliferation. Hydroxyproline levels increased in the wounds (p = 0.014) but were not different between the two groups (p = 0.14). CONCLUSIONS Lack of a striking effect of the MMP and TACE antagonist GM 6001 on postoperative adhesions suggests that MMP activity and TNF-alpha might not be major adhesiogenic factors.
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Affiliation(s)
- U Mirastschijski
- Department of Experimental Surgery, Malmo University Hospital, Lund University, Malmo, Sweden
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13
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Tatarenkov A, Bergström L, Jönsson RB, Serrão EA, Kautsky L, Johannesson K. Intriguing asexual life in marginal populations of the brown seaweed Fucus vesiculosus. Mol Ecol 2005; 14:647-51. [PMID: 15660953 DOI: 10.1111/j.1365-294x.2005.02425.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reproduction of attached large brown algae is known to occur only by sexual zygotes. Using microsatellites we show evolution of asexual reproduction in the bladder wrack promoting population persistence in the brackish water Baltic Sea (< 6 psu). Here a dwarf morph of Fucus vesiculosus is dominated by a single clone but clonal reproduction is also present in the common form of the species. We describe a possible mechanism for vegetative reproduction of attached algae, and conclude that clonality plays an important role in persistence and dispersal of these marginal populations, in which sexual reproduction is impaired by low salinity.
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Affiliation(s)
- A Tatarenkov
- Department of Marine Ecology, Tjärnö Marine Biological Laboratory, Göteborg University, SE 452 96 Strömstad, Sweden
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14
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Abstract
Until recently, our view of speciation was that reproductive isolation evolves during long periods of allopatry through the accumulation of genetic differences that result in genetic incompatibility. This view now contrasts with new findings that characters affecting reproductive isolation can diverge rapidly in sympatry as a result of natural selection. Recent studies combining research on phylogeny and ecology of natural populations cast new light on patterns, timescales and mechanisms, and emphasize the role of ecological factors in speciation. Studies of parallel speciation provide a strong case for sympatric speciation and for natural selection generating reproductive barriers.
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16
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Rolan-Alvarez E, Erlandsson J, Johannesson K, Cruz R. Mechanisms of incomplete prezygotic reproductive isolation in an intertidal snail: testing behavioural models in wild populations. J Evol Biol 1999. [DOI: 10.1046/j.1420-9101.1999.00086.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kostylev V, Erlandsson J, Johannesson K. Microdistribution of the polymorphic snailLittorina saxatilis(Olivi) in a patchy rocky shore habitat. ACTA ACUST UNITED AC 1997. [DOI: 10.1080/00785326.1997.10433386] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Rolán-Alvarez E, Rolán E, Johannesson K. Differentiation in radular and embryonic characters, and further comments on gene flow, between two sympatric morphs ofLittorina saxatilis(Olivi). ACTA ACUST UNITED AC 1996. [DOI: 10.1080/00785326.1996.10432459] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Abstract
Natural selection is one of the most fundamental processes in biology. However, there is still a controversy over the importance of selection in microevolution of molecular traits. Despite the general lack of data most authors hold the view that selection on molecular characters may be important, but at lower rates than selection on most phenotypic traits. Here we present evidence that natural selection may contribute substantially to molecular variation on a scale of meters only. In populations of the marine snail Littorina saxatilis living on exposed rocky shores, steep microclines in allele frequencies between splash and surf zone groups are present in the enzyme aspartate aminotransferase (allozyme locus Aat; EC. 2.6.1.1). We followed one population over 7 years, including a period of strong natural perturbation. The surf zone part of the population dominated by the allele Aat100 was suddenly eliminated by a bloom of a toxin-producing microflagellate. Downshore migration of splash zone snails with predominantly Aat120 alleles resulted in a drastic increase in surf zone frequency of Aat120, from 0.4 to 0.8 over 2 years. Over the next four to six generations, however, the frequency of Aat120 returned to the original value. We estimated the coefficient of selection of Aat120 in the surf zone to be about 0.4. Earlier studies show similar or even sharper Aat clines in other countries. Thus, we conclude that microclinal selection is an important evolutionary force in this system.
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Affiliation(s)
- K Johannesson
- Tjärnö Marine Biological Laboratory, Strömstad, Sweden
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Mattiasson-Nilo I, Sonn U, Johannesson K, Gosman-Hedström G, Persson GB, Grimby G. Domestic activities and walking in the elderly: evaluation from a 30-hour heart rate recording. Aging (Milano) 1990; 2:191-8. [PMID: 2095860 DOI: 10.1007/bf03323916] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The physical activity pattern among 43 subjects (25 women, 18 men) from the Intervention Study of Elderly in Gothenburg (IVEG) has been evaluated by means of heart rate monitoring, rating of perceived exertion and recording activities over a 30-hour period. These subjects had previously been interviewed about their activity pattern, including the duration of their daily walks. In 91% of the participants the average heart rate was below 100 beats/min during walking. Considerable individual variations were noted in the duration of domestic activities and of walks. Using heart rate levels equal to or above the average heart rate during walking as a criterion, it was found that 68% of the women, but only 17% of the men, spent more time on domestic activities than on walking. Nonetheless, it is suggested that in addition to walking, domestic activities, owing to their duration, are important in maintaining physical fitness in the elderly, especially among women. This should be taken into account when physical activity is being classified (to avoid bias in favour of men). A modified version of a previously published six-grade scale for the classification of physical activity has been suggested.
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Affiliation(s)
- I Mattiasson-Nilo
- Department of Rehabilitation Medicine, Gothenburg University, Sweden
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