Evaluation of Genetic Diversity and Virulence Potential of Legionella pneumophila Isolated from Water Supply Systems of Residential Buildings in Latvia

Legionella is an opportunistic pathogen with a biphasic life cycle that occasionally infects humans. The aim of the study was to assess the distribution of virulence genes and genetic diversity among L. pneumophila isolated from water supply systems of residential buildings in Latvia. In total, 492 water samples from 200 residential buildings were collected. Identification of Legionella spp. was performed according to ISO 11731, and 58 isolates were subjected to whole-genome sequencing. At least one Legionella-positive sample was found in 112 out of 200 apartment buildings (56.0%). The study revealed extensive sequence-type diversity, where 58 L. pneumophila isolates fell into 36 different sequence types. A total of 420 virulence genes were identified, of which 260 genes were found in all sequenced L. pneumophila isolates. The virulence genes enhC, htpB, omp28, and mip were detected in all isolates, suggesting that adhesion, attachment, and entry into host cells are enabled for all isolates. The relative frequency of virulence genes among L. pneumophila isolates was high. The high prevalence, extensive genetic diversity, and the wide range of virulence genes indicated that the virulence potential of environmental Legionella is high, and proper risk management is of key importance to public health.Peer reviewe

Crypthecodinium cohnii and Zymomonas mobilis syntrophy for production of omega 3 fatty acid

One of missions of industrial biotechnology is to produce valuable products from waste. In the current study we aim to establish a bioprocess of syntrophic co-cultivation of two microorganisms (Crypthecodinium cohnii and Zymomonas mobilis) at laboratory prototype level for bioconversion of renewables (molasses, the byproduct of sugar industry, and glycerol, byproduct of biodiesel production) into valuable vegetarian (produced by microorganisms) docosahexaenoic acid (DHA) from omega 3 fatty acid family. Cells of Z.mobilis strain (respiratory-deficient mutant derivative of the wild type strain Z.mobilis ATCC 29191) will be immobilized, following the previously described procedure of calcium alginate gel encapsulation. Mathematical modelling will be used for different components and at different stages of the syntrophic process to assist its improvement. The syntrophic bioprocess will be optimized with respect to (i) the medium composition, (ii) feed rates, (iii) oxygen supply, and (iv) the amounts of added immobilized Z. mobilis cells at particular stages of the fermentation. Genome and/or central carbon metabolism scale stoichiometric modelling and optimization will be performed to increase the utilization of cheap substrates and pre-treated residuals of C.cohnii. Bioprocess dynamics with respect to growth speed of batch fermentations will be modelled to ensure optimal proportions of syntrophic organisms, taking into account Z.mobilis production and immobilization as “slave” process of C.cohnii cultivation. Within several iterative cycles the fermentation data will be used for modelling and computer simulation of the bioprocess, and at the same time, the model-predicted dynamic behaviour of the system will aid further improvement of fermentation performance.publishersversionPeer reviewe

Cancer microcell initiation and determination

Funding Information: This project was supported by the University of Latvia Donor SIA “Mikrotīkls.” The University of Latvia Foundation administered this donation. Funding Information: This research was accomplished with the support of the Institute of Cardiology and Regenerative Medicine, University of Latvia. The cell culture cultivation was carried out in cooperation with the Latvian Biomedical Research and Study Centre. The confocal microscopy was carried out in collaboration with Carl Zeiss Microscopy Democenter Oberkochen, Germany. Publisher Copyright: © 2021, The Author(s).Background: Cancer remains one of the leading causes of death worldwide, despite the possibilities to detect early onset of the most common cancer types. The search for the optimal therapy is complicated by the cancer diversity within tumors and the unsynchronized development of cancerous cells. Therefore, it is necessary to characterize cancer cell populations after treatment has been applied, because cancer recurrence is not rare. In our research, we concentrated on small cancer cell subpopulation (microcells) that has a potential to be cancer resistance source. Previously made experiments has shown that these cells in small numbers form in specific circumstances after anticancer treatment. Methods: In experiments described in this research, the anticancer agents’ paclitaxel and doxorubicin were used to stimulate the induction of microcells in fibroblast, cervix adenocarcinoma, and melanoma cell lines. Mainly for the formation of microcells in melanoma cells. The drug-stimulated cells were then characterized in terms of their formation efficiency, morphology, and metabolic activity. Results: We observed the development of cancer microcells and green fluorescent protein (GFP) transfection efficiency after stress. In the time-lapse experiment, we observed microcell formation through a renewal process and GFP expression in the microcells. Additionally, the microcells were viable after anticancer treatment, as indicated by the nicotinamide adenine dinucleotide hydrogen phosphate (NADPH) enzyme activity assay results. Taken together, these findings indicate that cancer microcells are viable and capable of resisting the stress induced by anticancer drugs, and these cells are prone to chemical substance uptake from the environment. Conclusion: Microcells are not only common to a specific cancer type, but can be found in any tumor type. This study could help to understand cancer emergence and recurrence. The appearance of microcells in the studied cancer cell population could be an indicator of the individual anticancer therapy effectiveness and patient survival.publishersversionPeer reviewe

The use of advertisement by bank for development of communication with consumers.

Bakalaura darba „Reklāmas izmantošana bankas komunikācijas veidošanā ar patērētāju” mērķis ir izpētīt AS „SEB banka” reklāmas kampaņu efektivitāti un izstrādāt reklāmas pilnveidošanas plānu, lai veicinātu uzņēmuma komunikāciju ar patērētāju. Bakalaura darba apjoms ir 76 lapaspuses, tajā ievietotas 11 tabulas, 15 attēli, kā arī pievienots 1 pielikums. Izmantotās literatūras sarakstā ietvertas 45 publikācijas.Bachelors thesis “The use of advertisement by bank for development of communication with consumers” purpose is to investigate the SEB Bank campaign effectiveness and suggest optimization to promote the companys communication with the consumer. Bachelors workload is 76 pages, 11 tables into it, 15 images, as well as attached Annex 1. The references included 45 publications

Changes of the venous system in patients treated with PQ BYPASS: new innovative method for treating long occlusion of the femoral artery

PQ Bypass ir jauna un inovatīva metode pilnībā endovaskulārai femoropopliteālai šuntēšanai. Patlaban pasaulē ir pētījumi par PQ Bypass metodes, kur aprakstīta tās rezultāti arteriālajai sistēmai, bet nav atrodami pētījumi par PQ Bypass metodes ietekmi uz venozo sistēmu. Pētījuma mērķis ir izvērtēt PQ Bypass metodes ilgtermiņa ietekmi uz apakšējo ekstremitāšu venozo sistēmu. Materiāli un metodes: Prospektīvais pētījums tika veikts PSKUS Asinsvadu ķirurģijas centrā. Pētījumā tika analizēti 50 pacientu, kam ir C un D tipa bojājumi femoropopliteālajā segmentā pēc TASC II klasifikācijas, venozās sistēmas izmaiņas ilgtermiņā pēc PQ Bypass operācijas. Statistiskajām analīzēm tika izmantotas programmas: Prism v.8.0.2. (GraphPad Software Inc., La Jolla, Calif.). SPSS v 22.0(IBM Corp., Armonk, N.Y., USA). Par būtiskuma līmeni tika pieņemta p-vērtība < 0.05. Nozīmīgākie rezultāti: Pētījumā tika iekļauti 50 pacienti, kur lielāko daļu no pacientiem sastādīja vīrieši, kuru skaits bija 46 (92%) bet sieviešu skaits bija 4 (8%). Vidējais pacientu vecums bija 65,3 ± 8,3 gadi. Vidējais novērošanas laiks bija 18,5 mēneši. Vēnu duplikatūras tika konstatētas 18 (36,7%) pētījumā iesaistītajiem pacientiem. Pletizmogrāfiju VO un Vo mērījumu vidējie rezultāti nevienā no novērošanas laikiem abām kājām neatradās ārpus normas. VC mērījuma vidējie rezultāti operētajai kājai bija pazemināti kopš 3. mēneša (2,5% - 2,8%). To mērījuma vidējie rezultāti pēc operācijas operētajai kājai visu novērošanas laiku atradās zem normas (<25s). Villaltas skalas maksimālais punktu skaits pētījumā laikā nepārsniedza 4 punktus. Secinājumi: PQ Bypass metode negatīvi ietekmē venozās sistēmas uzpildes laiku (To), neietekmējot VO, VC un Vo rādītājus. PQ Bypass metode neietekmē apakšējo ekstremitāšu venozu sistēmu tik lielā mērā, lai veicinātu venozās nepietiekamības klīnisko ainu.PQ Bypass is a new and innovative method designed for a complete endovascular femoropopliteal shunting. At the time of conducting this study, there are only studies which describe its impact on the arterial system; however, there are no studies found regarding its impact on the venous system. The aim of this study is to evaluate PQ Bypass’s long-term impact on the lower limbs’ venous system. Materials and Methods: The prospective research was conducted in the Vascular Surgery Centre of Pauls Stradins Clinical University Hospital. PQ Bypass long-term post-operation impact of the venous system of 50 patients with C and D type lesions in the femoropopliteal segment after TASC II classification were analysed. The following software were used for the statistical analysis: Prism v.8.0.2. (GraphPad Software Inc., La Jolla, Calif.). SPSS v 22.0(IBM Corp., Armonk, N.Y., USA). The statystical significance level of this study was assumed to be p-value < 0.05. Results: The study involved 50 patients, from which 46 (92%) were male and 4 (8%) were female. The mean patient age was 65,3 ± 8,3 years. The mean follow-up period was 18,5 months. Venous duplication was found in 18 (36,7%) patients. In all of the follow-up periods, plethysmographic VO and Vo mean results for both limbs were within the physiological ranges. The mean results of the VC measurement for the target limb were decreased (2,5 % - 2,8%) since the third follow-up month. To measurement mean results after the surgery for the target limb were decreased (<25s) for the entire follow-up period. The maximum value of the Villalta score was not higher than 4 points for any patient. Conclusions: PQ Bypass method has a negative effect on the venous refilling time (To), without affecting VO, VC, and Vo values. PQ Bypass method does not affect the lower limbs’ venous system in such a degree, to promote the characteristics of venous insufficiency clinically

Modified Silyl-Terminated Polyether Polymer Blends with Bisphenol a Diglycidyl Ether Epoxy for Adhesive Applications

Epoxy resins have been used successfully as adhesives for many years. Despite many advantages of epoxy resins like high strength, chemical and heat resistance, in many applications they lack flexibility. During service under dynamic stress and variable environment this may lead to cracking and even failure of the adhesive joint. To improve epoxy resin adhesive performance they can be modified with other polymers. In this work modified silyl-terminated polyether polymer (MS Polymer) was used as elastic matrix material in various mixing ratio with epoxy resin. In the MS Polymer/epoxy blend A component consists from MS Polymer, amine catalyst, aminosilane and additional fillers. B component is based on bisphenol A diglycidyl ether (DGEBPA) epoxy resin with tin catalyst, water and fillers. When epoxy resin is mixed together with MS Polymer at the right ratio they form heterogenic matrix/domain structure which consists of the epoxy domains functioning as hard segments in elastic MS Polymer matrix [1]. When A and B components are mixed together, curing happens by epoxy reacting with amine catalyst, at the same time MS Polymer reacting with water. Aminosilane links MS Polymer with epoxy. Tensile stress-strain characteristics according to DIN 53504 were determined by using Zwick/Roell Z010 universal testing machine. Fracture surfaces of brittle-broken test specimens were observed by using Mira/LMU field emission scanning electron microscope (TESCAN a.s.)

Socio-Economic Analysis of Water Disinfection with Electrolysis in Latvia

Drinking water disinfection is necessary in order to minimize multiplication of microorganisms in engineering water supply systems and to eliminate the possibility of human infection, which could lead not only to deterioration of the public health and working abilities but, consequently, to significant economic losses. This is a serious problem in developed countries and partially in Latvia too, as significant number of people consume low-quality water from individual wells and have no access to the centralized water supply systems [1]. By improving microbiologic quality of drinking water in de-centralized water supply systems, number of infections caused by poor water quality will be significantly decreased

Rheological, Mechanical and Adhesion Properties of Two Component Adhesive based on Modified Silyl-Terminated Polyether Polymer and Epoxy Resin

Today an increasing interest in two component adhesive products can be sensed in the market. The driving force requesting more specific adhesive materials is automotive industry for bonding of light-weight structures or challenging designs. These requirements from industry make to seek for new raw material types to formulate adhesive systems with higher strength, broad superior adhesion spectrum and other demanding properties. The combination of epoxy resin with modified silyl-terminated polyether polymer (MS Polymer) is supposed to deliver a two component adhesive that shows superior strength compared to pure MS Polymer based adhesives, while combining all the other positive features from both polymer resin types. In two component adhesive formulation MS Polymer and epoxy hardener are main ingredients of one component and epoxy, MS Polymer catalyst and water are main ingredients of other component. Depending on the amount of methoxysilyl groups various MS Polymer types, namely, di-functional MS Polymers (DMS) and tri-functional MS Polymers (TMS), were used. Rheological characteristics were measured by using Bohlin CVO 100 rheometer. Instrument was equipped with 20 mm diameter spindle in plate-plate geometry with gap size 1000 m. Tests at 23 oC were performed in oscillatory shear mode at frequency 1.5 Hz and strain 0.15. Dynamic storage G’ and loss moduli G” were recorded as functions of the reaction time. Adhesive and tensile stress-strain characteristics were determined by using Zwick/Roell Z010 universal testing machine. Tensile tests were made according to DIN 53504. Lap shear tests were made according to EN 1465. Samples were tested after 1, 7, 14, 21 and 28 days of curing

Antimicrobial Resistance in <i>Enterococcus</i> spp. Isolates from Red Foxes (<i>Vulpes vulpes</i>) in Latvia

Antimicrobial resistance (AMR) is an emerging public health threat and is one of the One Health priorities for humans, animals, and environmental health. Red foxes (Vulpes vulpes) are a widespread predator species with great ecological significance, and they may serve as a sentinel of antimicrobial resistance in the general environment. The present study was carried out to detect antimicrobial resistance, antimicrobial resistance genes, and genetic diversity in faecal isolates of red foxes (Vulpes vulpes). In total, 34 Enterococcus isolates, including E. faecium (n = 17), E. faecalis (n = 12), E. durans (n = 3), and E. hirae (n = 2), were isolated. Antimicrobial resistance to 12 antimicrobial agents was detected with EUVENC panels using the minimum inhibitory concentration (MIC). The presence of antimicrobial resistance genes (ARGs) was determined using whole-genome sequencing (WGS). Resistance to tetracycline (6/34), erythromycin (3/34), ciprofloxacin (2/34), tigecycline (2/34), and daptomycin (2/34) was identified in 44% (15/34) of Enterococcus isolates, while all the isolates were found to be susceptible to ampicillin, chloramphenicol, gentamicin, linezolid, teicoplanin, and vancomycin. No multi-resistant Enterococcus spp. were detected. A total of 12 ARGs were identified in Enterococcus spp., with the presence of at least 1 ARG in every isolate. The identified ARGs encoded resistance to aminoglycosides (aac(6′)-I, ant(6)-Ia, aac(6′)-Iih and spw), tetracyclines (tet(M), tet(L) and tet(S)), and macrolide–lincosamide–streptogramin AB (lnu(B,G), lsa(A,E), and msr(C)), and their presence was associated with phenotypical resistance. Core genome multilocus sequence typing (cgMLST) revealed the high diversity of E. faecalis and E. faecium isolates, even within the same geographical area. The distribution of resistant Enterococcus spp. in wild foxes in Latvia highlights the importance of a One Health approach in tackling AMR