Identification and Characterization of Yersinia from Food and Environmental Sources

Yersinia genus includes currently 18 species: Yersinia pestis, Yersinia pseudotuberculosis, Yersinia enterocolitica, Yersinia frederiksenii, Yersinia intermedia, Yersinia kristensenii, Yersinia bercovieri, Yersinia mollaretii, Yersinia rohdei, Yersinia ruckeri, Yersinia aldovae, Yersinia aleksiciae, Yersinia massiliensis, Yersinia similis, Yersinia entomophaga, Yersinia nurmii, Yersinia pekkanenii and Yersinia wautersii. The history of the genus Yersinia can be dated back to 1883. In 1965, the genus consisted of only three species: Y. enterocolitica, Y. pseudotuberculosis and Y. pestis. Since then the taxonomy of the genus has been under tremendous change over the years, and especially the taxonomy of Y. enterocolitica, of which many new species have been separated from. Still Y. enterocolitica is a group of very heterogeneous bacteria, which can be divided into 6 biotypes and about 30 serotypes and into pathogenic and non-pathogenic strains. This variability makes the identification of Y. enterocolitica very challenging. In the thesis, two Yersinia species; Y. nurmii and Y. pekkanenii are described. These species were characterized by polyphasic taxonomic methods, including of 16S rRNA gene analysis, multilocus sequence analysis (MLSA) of housekeeping genes glnA, gyrB, recA and HSP60, DNA-DNA hybridization studies, 16S and 23S rRNA gene restriction fragment length polymorphism (RFLP), and phenotyping. Y. nurmii was isolated from broiler meat packaged under modified atmosphere, and Y. pekkanenii from water, soil and lettuce samples. In the 16S rRNA gene analysis and the 16S and 23S rRNA gene RFLP analysis, these two species grouped with other Yersinia, but in separate clusters. In the phylogenetic analysis of separate or concatenated housekeeping genes, the species formed unique monophyletic groups in all phylogenetic trees constructed. Y. nurmii had a phenotypic profile most similar to that of Y. ruckeri. Y. pekkanenii could not be differentiated from Y. pseudotuberculosis using phenotypic tests. Methods of polyphasic taxonomy were also used to estimate the taxonomic position of European Y. enterocolitica strains of non-pathogenic biotype 1A. Y. enterocolitica has been divided into two subspecies; Y. enterocolitica subsp. enterocolitica and Y. enterocolitica subsp. palearctica. Both subspecies consist of pathogenic and non-pathogenic biotypes. In this thesis, 212 Y. enterocolitica strains were characterized by numerical analysis of HindIII ribopatterns (16S and 23S rRNA gene RFLP). These strains consisted of 162 strains of biotype 1A and 50 strains of biotypes 2 to 4 isolated from different sources in Europe during years 1997-2013. Phylogenetic relatedness of 20 representative Y. enterocolitica strains including 15 biotype 1A strains was further studied by the multilocus sequence analysis of four housekeeping genes (glnA, gyrB, recA and HSP60). The biotype 1A strains studied were found to form a separate genomic group, which differed from Y. enterocolitica subsp. enterocolitica and Y. enterocolitica subsp. palearctica, with suggestion of the existence of a subspecies formed by non-pathogenic Y. enterocolitica biotype 1A strains. Finally, while studying Enterobacteriaceae in cold-stored (6 °C), modified atmosphere-packaged (MAP) pig cheek (musculus masseter) and hind leg meat (musculus semimembranosus), it was noticed that the pathogenic Y. enterocolitica subsp. palearctica bioserotype 4/O:3 multiplied into high numbers from a non-detectable level in (MAP) pig cheek meat. The Enterobacteriaceae isolated in this study were identified by 16S and 23S rRNA gene RFLP using the HindIII enzyme. Y. enterocolitica bioserotype 4/O:3 is the most common pathogenic bioserotype word-wide, and it can be transmitted to humans through raw or undercooked pork. Usually the growth of Enterobacteriaceae is inhibited by a modified atmosphere with 20% or more CO2 at refrigerated temperatures. However, in this study, high numbers of Y. enterocolitica bioserotype 4/O:3 was observed in MAP cold-stored pig cheek meat, with a concentration of 30% CO2 and 70% O2 in the packages.Yersinia on yksi Enterocacteriaceae- heimoon kuuluvista bakteerisuvuista. Suvun tunnetuin jäsen on Yersinia pestis, mustan surman aiheuttaja. Tällä hetkellä Yersinia-sukuun kuuluu yhteensä 18 lajia; Yersinia pestis, Yersinia pseudotuberculosis, Yersinia enterocolitica, Yersinia frederiksenii, Yersinia intermedia, Yersinia kristensenii, Yersinia bercovieri, Yersinia mollaretii, Yersinia rohdei, Yersinia ruckeri, Yersinia aldovae, Yersinia aleksiciae, Yersinia massiliensis, Yersinia similis, Yersinia entomophaga, Yersinia nurmii, Yersinia pekkanenii sekä Yersinia wautersii. Yersinia-suvun historian voidaan katsoa alkaneen jo vuonna 1883. Vuonna 1965 suku sisälsi vain kolme lajia: Y. enterocolitica, Y. pseudotuberculosis ja Y. pestis. Nämä kolme lajia ovat suvun ainoat ihmisille patogeeniset (sairauksia aiheuttavat) lajit. Väitöskirjatyössä on kuvattu kaksi uutta bakteerilajia; Y. nurmii ja Y. pekkanenii. Tutkimuksissa käytettiin taksonomisia (tieteellisen eliöiden luokittelun) menetelmiä, kuten DNA:n emäsparien pitoisuuksien määrittäminen, DNA-DNA hybridisaatio sekä proteiineja koodaavien geenisekvenssien vertailu. Y. nurmii eristettiin suojakaasuun pakatusta broilerin lihasta, ja Y. pekkanenii vesi- ja maanäytteistä sekä salaatista. Bakteerit nimettiin edesmenneiden eläinlääkäreiden ja elintarvikehygienian professoreiden Esko Nurmen ja Timo Pekkasen kunniaksi. Yersinia- suku on muuttunut valtavasti vuosien varrella, ja erityisesti Y. enterocolitica on jakautunut useisiin uusiin lajeihin. Edelleen Y. enterocolitica on kuitenkin erittäin heterogeenisten bakteerien ryhmä, joka voidaan jakaa 6 biotyyppiin ja noin 30 serotyyppiin sekä patogeenisiin ja ei-patogeenisiin kantoihin. Tämä vaihtelu tekee Y. enterocolitican tunnistamisesta erittäin haastavaa. Y. enterocolitica on tieteellisesti jaettu kahteen alalajiin; Y. enterocolitica subsp. enterocolitica ja Y. enterocolitica subs. palearctica. Alalajimääritelmä on ongelmallinen, sillä molempiin alalajeihin kuuluu sekä ei-patogeenisia että patogeenisia kantoja. Yhdessä väitöskirjan tutkimuksessa on selvitetty ei-patogeenisten kantojen luokittelua. Ei-patogeeniset, Euroopasta eristetyt biotyypin 1A kannat erottuivat taksonomisissa tutkimuksissa erilleen patogeenisista kannoista. Tulosten perusteella alalajijakoa tulisi täsmentää. Y. enterocolitica 4/O:3 on maailmanlaajuisesti yleisin patogeeninen bioserotyyppi. Tämä leviää erityisesti raa’an tai riittämättömästi kuumennetun lihan välityksellä. Sikoja pidetään tärkeimpänä 4/O:3 kantojen lähteenä, ja nämä bakteerit voivat levitä sikojen nielurisoista lihaan teurastuksen yhteydessä. Yksi väitöskirjan artikkeli käsittelee patogeenisten 4/O:3 bakteerien lisääntymistä suojakaasuun pakatuissa sian poskilihoissa kylmäsäilytyksen aikana. Tavallisesti näiden bakteerien kasvua estetään pakkaamalla liha suojakaasuseokseen, jossa on yli 20% hiilidioksidia, sekä säilyttämällä tuotteet jääkaappilämpötiloissa. Tässä tutkimuksessa havaittiin kuitenkin suuria määriä bioserotyyppiä 4/O:3 suojakaasuun (30% CO2 ja 70% O2) pakatussa 6°C:ssa säilytetyssä sian poskilihassa. Tuotteissa ruokamyrkytyksiä aiheuttavan bioserotyypin 4/O:3 kasvu oli huomattavaa, ja tuotteet voivat täten aiheuttaa elintarvikehygieenisen riskin

Altered N100-potential associates with working memory impairment in Parkinson's disease

The diagnosis of cognitive impairment and dementia often occurring with Parkinson's disease (PD) is still based on the clinical picture and neuropsychological examination. Ancillary methods to detect cognitive decline in these patients are, therefore, needed. Alterations in the latencies and amplitudes of evoked response potential (ERP) components N100 and P200 have been described in PD. Due to limited number of studies their relation to cognitive deficits in PD remains obscure. The present study was designed to examine if alterations in the N100- and P200-potentials associate with neuropsychological impairment in PD. EEG-ERP was conducted to 18 PD patients and 24 healthy controls. The patients underwent a thorough neuropsychological evaluation. The controls were screened for cognitive impairment with Consortium to Establish Alzheimer's disease (CERAD)-testing and a normal result were required to be included in the study. The N100-latency was prolonged in the patients compared to the controls (p = 0.05). In the patients, the N100 latency correlated significantly with a visual working memory task (p = 0.01). Also N100 latency was prolonged and N100 amplitude habituation diminished in the patients achieving poorly in this task. We conclude that prolonged N100-latency and diminished amplitude habituation associate with visual working memory impairment in PD.Peer reviewe

Satakielen polkka : Mestaripelimanni Tuure Niskasen soittotyyli ja soitteet

Opinnäytetyössäni perehdyin ylä-savolaisen mestaripelimanni Tuure Niskasen soittotyyliin ja soitteisiin. Opinnäytetyötä varten nuotinsin 35 Tuure Niskasen soittamaa sävelmää ja tämän työn pohjalta pyrin selvittämään Tuure Niskasen soittotyylin ominaisimmat piirteet. Soittotyyliä analysoidessani kiinnitin huomiota korukuvioiden, rytmin, jousen ja sävellajien käyttöön.In my thesis I assessed master pelimanni fiddler Tuure Niskanen's playing style and tunes. For this thesis I transcribed 35 tunes. Based on these notations I aspired to define Tuure Niskanen's playing style. In the analysis of the playing style, I observed ornaments, rhythm, key and use of bow

Urban drinking and driving:comparison of electric scooter and bicycle related accidents in facial fracture patients

In recent years, electric scooters (e-scooter) have emerged as an alternative mode of urban transport due to their availability and effortless use. However, e-scooter-related trauma and injuries, especially to the head, have received wide media coverage and raised public concern about their safety. We aim to determine and compare clinically relevant variables, incidence, and severity between bicycle and e-scooter-related facial fractures and potential protective measures for injury prevention. This retrospective study comprised all patients admitted to a tertiary trauma center with bicycle or e-scooter-related facial fractures between January 2019 and October 2020. Patient- and injury-related variables, including demographics, injury mechanisms, helmet use, influence of alcohol, types of facial injuries, types of other injuries, given treatment, and hospital stay, were collected, analysed, and compared between bicycle and e-scooter injuries. Altogether 169 patients with facial fractures, 124 bicycle-related injuries (73.4%) and 45 e-scooter-related injuries (26.6%) were included. Alcohol involvement was significantly higher in e-scooter patients (88.9%) than in bicycle patients (31.5%) (p<0.001). Driving under the influence of alcohol was associated with driving without a helmet in both groups (p<0.001). In multivariate analyses, e-scooter accidents were 18 times more likely to occur under the influence of alcohol (OR 17.85, p<0.001) and were more likely to involve collision with a stationary object (OR 3.81, p=0.028). E-scooter patients were significantly younger (OR 0.95, p<0.001) and had significantly more cranial fractures (OR 10.15, p=0.014) than bicycle patients. Compared with patients in bicycle accidents, facial fracture patients injured in e-scooter accidents are younger, are more likely under the influence of alcohol, and sustain more severe craniofacial skeleton fractures. Our results for both groups of patients advocate stricter adherence to helmet and road safety legislation as well as public education for injury prevention

Sports-based distribution of facial fractures - findings from a four-season country

Objective The aim of this study was to elucidate the relationship between injury mechanisms and sports-related facial fractures, and to evaluate the changes in incidence rates of facial fractures sustained in sports-related events in a 30-year period. Material and methods This retrospective cohort study included all patients sports-related facial fractures admitted to a tertiary trauma centre during 2013-2018. Specific fracture types, sports, injury mechanisms as well as patient- and injury related variables are presented. The results underwent evaluated statistically with logistic regression analysis. Results Facial fractures occurred most frequently while playing ice hockey and football. Unilateral zygomatic-maxillary-orbital and isolated mandibular fractures accounted for 74.2% of all fracture types. In total, 99 patients (46.5%) required surgical intervention for their facial injuries. About 12.7% of patients sustained associated injuries in addition to facial fractures. Overall, the number of sports-related facial fractures has increased during the last three decades mostly due to the surging rates of ice hockey- and football-related facial fractures. Conclusions Sport-related facial fractures have markedly increased in different sports disciplines during the past decades. The use of safety gear to protect the facial area should be enforced particularly in ice hockey.Peer reviewe

Desulfovibrio Bacteria Are Associated With Parkinson's Disease

Parkinson's disease (PD) is the most prevalent movement disorder known and predominantly affects the elderly. It is a progressive neurodegenerative disease wherein alpha-synuclein, a neuronal protein, aggregates to form toxic structures in nerve cells. The cause of Parkinson's disease (PD) remains unknown. Intestinal dysfunction and changes in the gut microbiota, common symptoms of PD, are evidently linked to the pathogenesis of PD. Although a multitude of studies have investigated microbial etiologies of PD, the microbial role in disease progression remains unclear. Here, we show that Gram-negative sulfate-reducing bacteria of the genus Desulfovibrio may play a potential role in the development of PD. Conventional and quantitative real-time PCR analysis of feces from twenty PD patients and twenty healthy controls revealed that all PD patients harbored Desulfovibrio bacteria in their gut microbiota and these bacteria were present at higher levels in PD patients than in healthy controls. Additionally, the concentration of Desulfovibrio species correlated with the severity of PD. Desulfovibrio bacteria produce hydrogen sulfide and lipopolysaccharide, and several strains synthesize magnetite, all of which likely induce the oligomerization and aggregation of alpha-synuclein protein. The substances originating from Desulfovibrio bacteria likely take part in pathogenesis of PD. These findings may open new avenues for the treatment of PD and the identification of people at risk for developing PD.Peer reviewe

Associated Injuries Are Common Among Patients With Bicycle-Related Craniofacial Fractures

Purpose: Ample evidence exists on the relationship between bicycle injuries and craniofacial fractures. However, as the mechanism behind these injuries is often multifactorial, the presence of associated injuries (AIs) in this study population requires further examination. We hypothesized that patients with craniofacial fracture injured in bicycle accidents are at high risk of sustaining severe AIs, especially those of the head and neck region. Patients and Methods: The investigators performed a retrospective study on all patients with bicyclerelated craniofacial fracture admitted to a tertiary trauma centre during 2013 to 2018. The predictor variable was defined as any type of craniofacial fracture. The outcome variable was defined as any kind of AI. Other study variables included demographic and injury-related parameters. Variables were analyzed using bivariate and Firth's logistic regression analyses. Results: A total of 407 patients were included in the analysis. Our results revealed that AIs were present in 150 (36.9%) patients; there were multiple AIs in 47 cases. Traumatic brain injuries followed by upper limb injuries were the most frequent AIs. Severe head and neck injuries were present in 20.1% of all patients with craniofacial fracture. AIs were observed in 57.4% of patients with combined midfacial fractures (P < .001). Helmet use had a protective effect against traumatic brain injuries (P < .001). Conclusions: Our results suggest that AIs are relatively common in this specific patient population. Close co-operation in multidisciplinary trauma centers allowing comprehensive evaluation and treatment can be recommended for patients with bicycle-related craniofacial fracture. (C) 2021 American Association of Oral and Maxillofacial Surgeons.Peer reviewe

Geometrical magnetoresistance effect and mobility in graphene field-effect transistors

Further development of the graphene field-effect transistors (GFETs) for high-frequency electronics requires accurate evaluation and study of the mobility of charge carriers in a specific device. Here, we demonstrate that the mobility in the GFETs can be directly characterized and studied using the geometrical magnetoresistance (gMR) effect. The method is free from the limitations of other approaches since it does not require an assumption of the constant mobility and the knowledge of the gate capacitance. Studies of a few sets of GFETs in the wide range of transverse magnetic fields indicate that the gMR effect dominates up to approximately 0.55 T. In higher fields, the physical magnetoresistance effect starts to contribute. The advantages of the gMR approach allowed us to interpret the measured dependencies of mobility on the gate voltage, i.e., carrier concentration, and identify the corresponding scattering mechanisms. In particular, the range of the fairly constant mobility is associated with the dominating Coulomb scattering. The decrease in mobility at higher carrier concentrations is associated with the contribution of the phonon scattering. Analysis shows that the gMR mobility is typically 2-3 times higher than that found via the commonly used drain resistance model. The latter underestimates the mobility since it does not take the interfacial capacitance into account.Comment: The following article has been submitted to Applied Physics Letters. After it is published, the DOI will be found her

High-performance silicon-based nano-thermoelectric bolometers for uncooled infrared sensing

Infrared (IR) sensors and photodetector arrays are employed in various imaging applications (such as night vision), remote temperature measurement, and chemical analysis. These applications are in space and environmental sensing, transport, health and medicine, safety, security, defense, industry, agriculture, etc. Optical chemical analysis employs IR absorption spectroscopy which enables the identification and quantification of gases, liquids, and materials based on their unique absorption spectra which are feature-rich in the IR region. State-of-the-art (SoA) quantum photodetectors utilize either photoconductivity or the photovoltaic effect. Commercial quantum photodetectors are widely available in the spectral range from UV to short-wave infrared (SWIR), but in mid-wave IR (MWIR) and long-wave IR (LWIR), they require exotic materials and cooling to maintain high sensitivity. Thermal detectors (bolometers) are a competing technology that can reach high sensitivities in IR without the need for cooling and can be manufactured using widely available semiconductor technologies. SoA bolometers include resistive bolometers, diode- or transistor-based bolometers, and thermoelectric bolometers. By utilizing nanomaterials and integrated design, we have minimized the thermal mass and demonstrated fast and sensitive nano-thermoelectric IR bolometers with high thermoelectric efficiency. We review the application and development of the silicon-based nano-thermoelectric infrared bolometers: modelling, design, fabrication, and electro-optical characteristics. The enabling materials, silicon nanomembranes, are also discussed, and the first devices used to test the potential of these nanomembranes, the electro-thermal devices, are reviewed and new experimental results are presented.</p

Magnetic Nanoparticles in Human Cervical Skin

Magnetic iron oxide nanoparticles, magnetite/maghemite, have been identified in human tissues, including the brain, meninges, heart, liver, and spleen. As these nanoparticles may play a role in the pathogenesis of neurodegenerative diseases, a pilot study explored the occurrence of these particles in the cervical (neck) skin of 10 patients with Parkinson's disease and 10 healthy controls. Magnetometry and transmission electron microscopy analyses revealed magnetite/maghemite nanoparticles in the skin samples of every study participant. Regarding magnetite/maghemite concentrations of the single-domain particles, no significant between-group difference was emerged. In low-temperature magnetic measurement, a magnetic anomaly at similar to 50 K was evident mainly in the dermal samples of the Parkinson group. This anomaly was larger than the effect related to the magnetic ordering of molecular oxygen. The temperature range of the anomaly, and the size-range of magnetite/maghemite, both refute the idea of magnetic ordering of any iron phase other than magnetite. We propose that the explanation for the finding is interaction between clusters of superparamagnetic and single-domain-sized nanoparticles. The source and significance of these particles remains speculative.Peer reviewe