Publications by authors named "Aleksandra Biedrzycka"

Genetic monitoring of populations currently attracts interest in the context of the Convention on Biological Diversity but needs long-term planning and investments. However, genetic diversity has been largely neglected in biodiversity monitoring, and when addressed, it is treated separately, detached from other conservation issues, such as habitat alteration due to climate change. We report an accounting of efforts to monitor population genetic diversity in Europe (genetic monitoring effort, GME), the evaluation of which can help guide future capacity building and collaboration towards areas most in need of expanded monitoring.

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Understanding the evolutionary mechanisms behind invasion success enables predicting which alien species and populations are the most predisposed to become invasive. Parasites may mediate the success of biological invasions through their effect on host fitness. The evolution of increased competitive ability (EICA) hypothesis assumes that escape from parasites during the invasion process allows introduced species to decrease investment in immunity and allocate resources to dispersal and reproduction.

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Rapid adaptation is common in invasive populations and is crucial to their long-term success. The primary target of selection in the invasive species' new range is standing genetic variation. Therefore, genetic drift and natural selection acting on existing variation are key evolutionary processes through which invaders will evolve over a short timescale.

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Associations between genetic variants and susceptibility to infections have long been studied in free-living hosts so as to infer the contemporary evolutionary forces that shape the genetic polymorphisms of immunity genes. Despite extensive studies of proteins interacting with pathogen-derived ligands, such as MHC (major histocompatilbility complex) or TLR (Toll-like receptors), little is known about the efferent arm of the immune system. Cytokines are signalling molecules that trigger and modulate the immune response, acting as a crucial link between innate and adaptive immunity.

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Background: Parasites may mediate the success of biological invasions through their effect on host fitness and thus, on host population growth and stability. However, a release from the pressure of parasites is strongly related to the genetic differentiation of the host. In invasive host populations, the number of available genetic variants, allowing them to 'fight' the infection, are likely to be influenced by founder events and genetic drift.

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The adaptive potential of invasive species is related to the genetic diversity of the invader, which is influenced by genetic drift and natural selection. Typically, the genetic diversity of invaders is studied with neutral genetic markers; however, the expectation of reduced diversity has not been consistently supported by empirical studies. Here, we describe and interpret genetic diversity at both neutral microsatellite loci and the immune-related MHC-DRB locus of native and invasive populations of raccoon to better understand of how drift and selection impact patterns of genetic diversity during the invasion process.

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AmpliSAS and AmpliHLA are web server tools for automatic genotyping of MHC genes from high-throughput sequencing data. AmpliSAS is designed specifically to analyze amplicon sequencing data from non-model species and it is able to perform de-novo genotyping without any previous knowledge of the reference alleles. AmpliHLA is a human-specific version, it performs HLA typing by comparing sequenced variants against human reference alleles from the IMGT/HLA database.

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Article Synopsis
  • Pathogens significantly influence the evolution and maintenance of the diverse MHC genes in vertebrates, with a focus on sedge warblers' highly duplicated MHC genes.
  • High-throughput MHC genotyping analyzed how avian malaria parasites impact the fluctuations in MHC class I supertypes over time, revealing that malaria infection risks correlate with changes in MHC frequencies.
  • Individuals with greater MHC class I supertype diversity showed increased resistance to avian malaria, suggesting that high diversity in these genes may be critical for survival against such infections in birds.
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Background: Recent work suggests that gene duplications may play an important role in the evolution of immunity genes. Passerine birds, and in particular Sylvioidea warblers, have highly duplicated major histocompatibility complex (MHC) genes, which are key in immunity, compared to other vertebrates. However, reasons for this high MHC gene copy number are yet unclear.

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Characterization of highly duplicated genes, such as genes of the major histocompatibility complex (MHC), where multiple loci often co-amplify, has until recently been hindered by insufficient read depths per amplicon. Here, we used ultra-deep Illumina sequencing to resolve genotypes at exon 3 of MHC class I genes in the sedge warbler (Acrocephalus schoenobaenus). We sequenced 24 individuals in two replicates and used this data, as well as a simulated data set, to test the effect of amplicon coverage (range: 500-20 000 reads per amplicon) on the repeatability of genotyping using four different genotyping approaches.

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The role of pathogens in dynamics of endangered species is not fully understood, and the effect of infection often interacts with other processes affecting those species, such as fragmentation and isolation or loss of genetic variation. Small, isolated populations are prone to losing functional alleles due to demographic processes and genetic drift, which may diminish their ability to resist infection if immune genes are affected. Demographic processes may also alter the selective pressure exerted by a parasite, as they influence the rate of parasite transmission between individuals.

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Objectives: The purpose of the present study was to assess, by near-infrared spectroscopy with an INVOS oximeter during the vascular occlusion test (VOT), the influence of cardiopulmonary bypass (CPB) on tissue saturation in the thenar muscle. The secondary aim was to compare the effects of propofol and sevoflurane anaesthesia on tissue saturation.

Methods: This was a prospective, randomized, open-label study.

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Conventional monitoring during surgery and intensive care is not sufficiently sensitive to detect acute changes in vital organs perfusion, while its good quality is critical for maintaining their function. Disturbed vital organ perfusion may lead to the development of postoperative complications, including neurological sequel and renal failure. Near-infra-red spectroscopy (NIRS) represents one of up-to-date techniques of patient monitoring which is commonly used for the assessment of brain oximetry in thoracic aorta surgery, and - increasingly more often -in open-heart surgery.

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Background: Several studies have highlighted that volatile anaesthetics improve myocardial protection in cardiopulmonary bypass coronary surgery. However, the haemodynamic effect of desflurane in off-pump coronary surgery has not been clarified yet. Our study hypothesis was that desflurane-fentanyl anaesthesia could decrease myocardial injury markers and improve haemodynamics compared to propofol-fentanyl in patients undergoing off-pump coronary surgery.

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We characterized partial sequences of 18S rDNA from sedge warblers infected with a parasite described previously as Hepatozoon kabeeni. Prevalence was 47% in sampled birds.We detected 3 parasite haplotypes in 62 sequenced samples from infected animals.

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Loss of genetic variation may render populations more vulnerable to pathogens due to inbreeding depression and depletion of variation in genes responsible for immunity against parasites. Here we review the evidence for the significance of variation in genes of the Major Histocompatibility Complex (MHC) for conservation efforts. MHC molecules present pathogen-derived antigens to the effector cells of the immune system and thus trigger the adaptive immune response.

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The fragmentation of populations typically enhances depletion of genetic variation, but highly polymorphic major histocompatibility complex (MHC) genes are thought to be under balancing selection and therefore retain polymorphism despite population bottlenecks. In this study, we investigate MHC DRB (class II) exon 2 variation in 14 spotted suslik populations from two regions differing in their degree of habitat fragmentation and gene flow. We found 16 alleles that segregated in a sample of 248 individuals.

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