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"Whole genome sequence"
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EFSA statement on the requirements for whole genome sequence analysis of microorganisms intentionally used in the food chain
Microorganisms, genetically modified or not, may be used in the food chain as such or as production organisms of substances of interest. The placement of such microorganisms or derived substances/products in the European market may be subject to a pre‐market authorisation process. The authorisation process defines the need to perform a risk assessment to establish the safety and/or the efficacy of the microorganisms when used in the food chain as such or as production strains of substances of interest. In order to perform a risk assessment, the microorganism/s subject to the application for authorisation need/s to be characterised. In this regard, data obtained from whole genome sequence analysis can provide information on the unequivocal taxonomic identification of the strains and on the characterisation of their potential functional traits of concern which may include virulence factors, resistance to antimicrobials of clinical relevance for humans and animals, production of known toxic metabolites. In fact, in some areas of the regulated products, the use of whole genome sequence‐based data has been established as a requirement for the risk assessment. This document provides recommendations to applicants on how to describe the process and results which should be provided to the risk assessor in the context of an application for market authorisation of a regulated product. Indications are given on how to perform WGS and the quality criteria/thresholds that should be reached as well as the data and relevant information that need to be sent along whenever such kind of data is required.
Journal Article
Genomic and Phenotypic Characteristics in Geographically Separated Clinical Campylobacter jejuni ST353CC Isolates
2021
Campylobacter jejuni fecal isolates of eight international travelers, 5 of which had traveled to Ecuador and 3 to Bangladesh, were characterized, and the possible relationship between bacterial traits and clinical symptoms was further analyzed. All eight isolates belonged to the same Multi-Locus Sequence Type clonal complex (ST353CC). The three isolates from Bangladesh were all of the same sequence type (ST-9438), and when compared to isolates of various other sequence types, they had a larger quantity of unique genetic content, higher expression levels of some putative virulence genes involved in adhesion and invasion (flpA, ciaB and iamA), and showed higher adhesion levels to human HT-29 colon cancer cells in an in vitro infection model. However, in contrast to the seemingly higher pathogenic potential of these bacterial isolates, travelers infected with the ST-9438 isolates had no or only very mild symptoms, whereas the other individuals, whose bacterial isolates seemed to have less pathogenic potential, generally reported severe symptoms. When studying the 16S rRNA gene-based fecal microbiota in samples collected prior to travel, there was an individual variation in the relative abundance of the three major bacterial phyla Actinobacteria, Bacteroidetes and Firmicutes, but there were no associations between composition and diversity of microbiota and development of severe symptoms from the infection. It remains to be confirmed by larger studies whether an individual’s characteristics such as gut microbiota, might be related to the severity of symptoms in Campylobacter infections.
Journal Article
Increased accuracy of genomic predictions for growth under chronic thermal stress in rainbow trout by prioritizing variants from GWAS using imputed sequence data
2022
Through imputation of genotypes, genome‐wide association study (GWAS) and genomic prediction (GP) using whole‐genome sequencing (WGS) data are cost‐efficient and feasible in aquaculture breeding schemes. The objective was to dissect the genetic architecture of growth traits under chronic heat stress in rainbow trout (Oncorhynchus mykiss) and to assess the accuracy of GP based on imputed WGS and different preselected single nucleotide polymorphism (SNP) arrays. A total of 192 and 764 fish challenged to a heat stress experiment for 62 days were genotyped using a customized 1 K and 26 K SNP panels, respectively, and then, genotype imputation was performed from a low‐density chip to WGS using 102 parents (36 males and 66 females) as the reference population. Imputed WGS data were used to perform GWAS and test GP accuracy under different preselected SNP scenarios. Heritability was estimated for body weight (BW), body length (BL) and average daily gain (ADG). Estimates using imputed WGS data ranged from 0.33 ± 0.05 to 0.55 ± 0.05 for growth traits under chronic heat stress. GWAS revealed that the top five cumulatively SNPs explained a maximum of 0.94%, 0.86% and 0.51% of genetic variance for BW, BL and ADG, respectively. Some important functional candidate genes associated with growth‐related traits were found among the most important SNPs, including signal transducer and activator of transcription 5B and 3 (STAT5B and STAT3, respectively) and cytokine‐inducible SH2‐containing protein (CISH). WGS data resulted in a slight increase in prediction accuracy compared with pedigree‐based method, whereas preselected SNPs based on the top GWAS hits improved prediction accuracies, with values ranging from 1.2 to 13.3%. Our results support the evidence of the polygenic nature of growth traits when measured under heat stress. The accuracies of GP can be improved using preselected variants from GWAS, and the use of WGS marginally increases prediction accuracy.
Journal Article
EFSA statement on the requirements for whole genome sequence analysis of microorganisms intentionally used in the food chain
Microorganisms, genetically modified or not, may be used in the food chain either as active agents, biomasses or as production organisms of substances of interest. The placement of such microorganisms or their derived substances/products in the European market may be subject to a premarket authorisation process. The authorisation process requires a risk assessment in order to establish the safety and/or the efficacy of the microorganism(s) when used in the food chain as such, as biomasses or as production strains. This includes a full molecular characterisation of the microorganism(s) under assessment. For certain regulated products, the use of whole genome sequence (WGS) data of the microorganism is established as a requirement for the risk assessment. In this regard, data obtained from WGS analysis can provide information on the unambiguous taxonomic identification of the strains, on the presence of genes of concern (e.g. those encoding virulence factors, resistance to antimicrobials of clinical relevance for humans and animals, production of harmful metabolites or of clinically relevant antimicrobials) and on the characterisation of genetic modification(s) (where relevant). This document provides recommendations to applicants on how to describe and report the results of WGS analyses in the context of an application for market authorisation of a regulated product. Indications are given on how to perform genome sequencing and the quality criteria/thresholds that should be reached, as well as the data and relevant information that need to be reported, if required. This updated document replaces the EFSA 2021 Statement and reflects the current knowledge in technologies and methodologies to be used to generate and analyse WGS data for the risk assessment of microorganisms.
Journal Article
Pathogenic variants prevalence patients with diabetic kidney disease in Japan: A descriptive study
2025
Aims/Introduction The impact of rare pathogenic variants on diabetic kidney disease (DKD) has not been investigated in detail. Previous studies have detected pathogenic variants in 22% of Caucasian patients with DKD; however, this proportion may vary depending on ethnicity and updates to the database. Therefore, we performed a whole‐genome analysis of patients with DKD in type 2 diabetes mellitus in Japan, utilizing a recent database to investigate the prevalence of kidney‐related pathogenic variants and describe the characteristics of these patients. Materials and methods Whole‐genome sequencing was performed, and variants were analyzed following the GATK Best Practices. We extracted data on 790 genes associated with Mendelian kidney and genitourinary diseases. Pathogenic variants were defined based on the American College of Medical Genetics criteria, including both heterozygous and homozygous variants classified as pathogenic or likely pathogenic. Results Among 79 participants, heterozygous pathogenic variants were identified in 27 (34.1%), a higher prevalence than previously reported. No homozygous pathogenic variants were detected. The identified heterozygous pathogenic variants were roughly divided into 23.7% related to glomerulopathy, 36.8% related to tubulointerstitial disease, 10.5% related to cystic disease/ciliopathy, and 28.9% related to others. Diagnostic variants were found in 10 patients (12.7%) in seven genes (ABCC6, ALPL, ASXL1, BMPR2, GCM2, PAX2, and WT1), all associated with autosomal dominant congenital disease. Conclusions This study identified a considerable number of patients with DKD in Japan who carried kidney‐related heterozygous pathogenic variants. These findings suggest potential ethnic differences and highlight the impact of database updates on variant detection. Previous studies have identified pathogenic variants in 22% of Caucasian patients with diabetic kidney disease (DKD); however, this proportion may vary depending on ethnicity and updates to the database. Whole‐genome sequencing of 79 patients with DKD in Japan revealed that 34.1% had kidney‐related heterozygous pathogenic variants, and 12.7% had diagnostic variants for autosomal dominant congenital diseases, a higher prevalence than reported previously. These findings highlight ethnic differences and the importance of database updates in variant detection.
Journal Article
Australian Cattle Dogs with Neuronal Ceroid Lipofuscinosis are Homozygous for a CLN5 Nonsense Mutation Previously Identified in Border Collies
by
Kolicheski, A.
,
Mhlanga-Mutangadura, T.
,
Gilliam, D.
in
alleles
,
Animals
,
Australian Cattle Dog
2016
Abstract
Background
Neuronal ceroid lipofuscinosis (NCL), a fatal neurodegenerative disease, has been diagnosed in young adult Australian Cattle Dogs.
Objective
Characterize the Australian Cattle Dog form of NCL and determine its molecular genetic cause.
Animals
Tissues from 4 Australian Cattle Dogs with NCL-like signs and buccal swabs from both parents of a fifth affected breed member. Archived DNA samples from 712 individual dogs were genotyped.
Methods
Tissues were examined by fluorescence, electron, and immunohistochemical microscopy. A whole-genome sequence was generated for 1 affected dog. A TaqMan allelic discrimination assay was used for genotyping.
Results
The accumulation of autofluorescent cytoplasmic storage material with characteristic ultrastructure in tissues from the 4 affected dogs supported a diagnosis of NCL. The whole-genome sequence contained a homozygous nonsense mutation: CLN5:c.619C>T. All 4 DNA samples from clinically affected dogs tested homozygous for the variant allele. Both parents of the fifth affected dog were heterozygotes. Archived DNA samples from 346 Australian Cattle Dogs, 188 Border Collies, and 177 dogs of other breeds were homozygous for the reference allele. One archived Australian Cattle Dog sample was from a heterozygote.
Conclusions and Clinical Importance
The homozygous CLN5 nonsense is almost certainly causal because the same mutation previously had been reported to cause a similar form of NCL in Border Collies. Identification of the molecular genetic cause of Australian Cattle Dog NCL will allow the use of DNA tests to confirm the diagnosis of NCL in this breed.
Journal Article
Potential of Bifidobacterium lactis IDCC 4301 isolated from breast milk‐fed infant feces as a probiotic and functional ingredient
by
Ban, O‐Hyun
,
Kim, Dong Hyun
,
Bang, Won Yeong
in
Antibiotic resistance
,
Antibiotics
,
antimicrobial
2023
Probiotics provide important health benefits to the host by improving intestinal microbial balance and have been widely consumed as dietary supplements. In this study, we investigated whether Bifidobacterium lactis IDCC 4301 (BL), isolated from feces of breast milk‐fed infants, is safe to consume. Based on the guidelines established by the European Food Safety Authority (EFSA), safety tests such as antibiotic susceptibility, hemolysis, toxic compound formation (i.e., biogenic amine and d‐lactate), single‐dose acute oral toxicity, and extracellular enzymatic activities were performed. In addition, toxigenic genes, antibiotic resistance genes, and mobile genetic elements were investigated by analyzing the genome sequence of BL. BL was susceptible to eight antibiotics except for vancomycin and the absence of transferable resistance in the genome of this strain implied that vancomycin resistance is likely to be intrinsic. With regard to phenotypic characteristics, there was no concern of toxicity of this strain. Furthermore, BL utilized various carbohydrates and their conjugates through the activity of various endogenous carbohydrate‐utilizing enzymes. Interestingly, the supernatant of the BL showed strong antipathogenic activity against various infectious pathogens. Therefore, we suggest that BL should be a safe probiotic and can be used as a functional ingredient in the food, cosmetic, and pharmaceutical industries. Bifidobacterium lactis IDCC 4301 was isolated from breast milk‐fed infant feces. Its potential was evaluated as a probiotic and functional ingredient. Its whole‐genome sequence was analyzed. Its safety was evaluated based on the guidelines suggested by FAO/WHO and EFSA. Its supernatant showed strong antimicrobial activity against various pathogens.
Journal Article
Inferring epidemiologic dynamics from viral evolution: 2014–2015 Eurasian/North American highly pathogenic avian influenza viruses exceed transmission threshold, R0 = 1, in wild birds and poultry in North America
by
Hall, Jeffrey S.
,
Dusek, Robert J.
,
Grear, Daniel A.
in
basic pathogen reproductive number
,
highly pathogenic avian influenza
,
phylodynamics
2018
Highly pathogenic avian influenza virus (HPAIV) is a multihost pathogen with lineages that pose health risks for domestic birds, wild birds, and humans. One mechanism of intercontinental HPAIV spread is through wild bird reservoirs, and wild birds were the likely sources of a Eurasian (EA) lineage HPAIV into North America in 2014. The introduction resulted in several reassortment events with North American (NA) lineage low‐pathogenic avian influenza viruses and the reassortant EA/NA H5N2 went on to cause one of the largest HPAIV poultry outbreaks in North America. We evaluated three hypotheses about novel HPAIV introduced into wild and domestic bird hosts: (i) transmission of novel HPAIVs in wild birds was restricted by mechanisms associated with highly pathogenic phenotypes; (ii) the HPAIV poultry outbreak was not self‐sustaining and required viral input from wild birds; and (iii) reassortment of the EA H5N8 generated reassortant EA/NA AIVs with a fitness advantage over fully Eurasian lineages in North American wild birds. We used a time‐rooted phylodynamic model that explicitly incorporated viral population dynamics with evolutionary dynamics to estimate the basic reproductive number (R0) and viral migration among host types in domestic and wild birds, as well as between the EA H5N8 and EA/NA H5N2 in wild birds. We did not find evidence to support hypothesis (i) or (ii) as our estimates of the transmission parameters suggested that the HPAIV outbreak met or exceeded the threshold for persistence in wild birds (R0 > 1) and poultry (R0 ≈ 1) with minimal estimated transmission among host types. There was also no evidence to support hypothesis (iii) because R0 values were similar among EA H5N8 and EA/NA H5N2 in wild birds. Our results suggest that this novel HPAIV and reassortments did not encounter any transmission barriers sufficient to prevent persistence when introduced to wild or domestic birds.
Journal Article
Long-term Treatment with Methylene Blue in a Dog with Hereditary Methemoglobinemia Caused by Cytochrome b5 Reductase Deficiency
2017
Abstract
A juvenile male mixed breed dog was presented for lethargy, exercise intolerance, and aggression when touched on the head. Cyanosis, tachycardia, and tachypnea were observed and persisted during oxygen supplementation. Arterial blood gas analysis by co-oximetry identified an increased methemoglobin concentration (27%; normal, <2%) with normal arterial oxygen tension. The methemoglobinemia and associated clinical signs resolved after administration of methylene blue (1 mg/kg) IV, and the dog was discharged. The affected dog's whole-genome sequence contained 2 potentially causal heterozygous CYB5R3 missense mutations suggesting that cytochrome b5 reductase deficiency was responsible for the methemoglobinemia. This hypothesis was confirmed by enzyme analysis that identified cytochrome b5 reductase activity in the affected dog's erythrocytes to only approximately 6% of that in a control sample. Clinical signs recurred 11 days after discharge but normalized and the methemoglobin concentration decreased with methylene blue administration PO (1.5 mg/kg, initially daily and then every other day).
Journal Article
Estimating the Effective Population Size Across Space and Time in the Critically Endangered Western Chimpanzee in Guinea‐Bissau: Challenges and Implications for Conservation Management
by
Aleixo‐Pais, Isa
,
Bruford, Michael W.
,
Silva, Maria Joana Ferreira
in
Anthropogenic landscapes
,
Biodiversity
,
Biodiversity and Ecology
2025
The western chimpanzee (Pan troglodytes verus) is a Critically Endangered taxon. In Guinea‐Bissau (GB), the subspecies is increasingly threatened, but there is a lack of understanding regarding the degree of genetic threat faced by populations. This hinders the development of targeted conservation strategies and the prioritization of efforts by national agencies. In this study, we use microsatellite data from four parks located in southern GB and five whole‐genome sequences to estimate the effective population size (Ne) and infer the recent and ancient demographic history of populations using different methods. We also aim to integrate the different Ne estimates to improve our understanding of the evolutionary history and current demography of this great ape and to discuss the strengths and limitations of each estimator and their complementarity in informing conservation decisions. Results from the PSMC method suggest a large ancestral Ne, likely due to ancient structure over the whole subspecies distribution until approximately 10,000–15,000 years ago. After that, a change in connectivity, a real decrease in size, or a combination of both occurred, which reduced the then still large ancestral population to a smaller size (MSVAR: ~10,000 decreasing to 1,000–6,000 breeding individuals), possibly indicating a fragmentation into coastal and inland subpopulations. In the most recent past, contemporary Ne is close to 500 (GONE: 395–583, NeEstimator: 107–549), suggesting a high risk of extinction. The populations located at the coastal parks may have been small or isolated for several generations and are at higher risk, whereas the ones located inland exhibit higher long‐term Ne and can be considered a stronghold for chimpanzee conservation. Through combining different types of molecular markers and analytical methodologies, we tried to overcome the limitations of obtaining high‐quality DNA samples from wild threatened populations and estimated Ne at different temporal and spatial scales, which is crucial information to make informed conservation decisions at local and regional scales.
Journal Article