The reception and representation of English as an academic language among foreign students in Poland and its influence on (re)shaping individual identities

The article discusses selected problems of learning and using English as an academic language from the perspective of foreign students in Poland. The theoretical part of the paper concentrates on the issues related to the concept of identity and the status of English as an academic lingua franca, especially in the light of the growing role of English for Academic Purposes (EAP) in university education. Such theoretical background is intended to serve as a kind of introduction to the discussion which centres around the influence of this specific social variation of the English language on the process of shaping or reshaping identities among students who have decided to continue their education outside their native language environment in the multilingual context of a university language department. Seen from such a perspective, university courses in EAP may be treated as a form of practical implementation of multilingual pedagogy and, more specifically, the idea of inclusive “classrooms” with a particular goal-oriented curriculum. The empirical part of the article presents the research project which aimed to examine the above-mentioned phenomena as experienced by a group of language students of different ethnic and national background who have been studying (and living) in Poland for at least a year. The main research technique used in this qualitative study was the semi-structured interview, selected with a view to obtaining an in-depth picture and highly personalised account of the process of (re)constructing individual identities in a specific social context and educational setting

Badania nad mechanizmami działania i rozwoju oporności na bakteriocyny klasy II u bakterii Gram-dodatnich

Bakteriocyny to grupa peptydów lub białek wytwarzanych przez bakterie w celu zabijania lub hamowania wzrostu innych bakterii zasiedlających tę samą niszę ekologiczną. Zainteresowanie bakteriocynami wynika z ich potencjalnego zastosowania m.in. w konserwacji żywności i terapii zakażeń wywołanych przez antybiotykooporne szczepy bakterii chorobotwórczych. Liczba publikacji identyfikujących nowe szczepy bakterii produkujących bakteriocyny nieustannie wzrasta. Jednocześnie, zauważalny jest brak badań opisujących mechanizmy działania większości nowo zidentyfikowanych bakteriocyn, a także mechanizmy nabywania oporności na te bakteriocyny i oporności krzyżowej na antybiotyki. Dokładne poznanie tych zagadnień pozwoli na opracowanie wytycznych zapewniających najbardziej efektywne, bezpieczne i długotrwałe stosowanie bakteriocyn bez ryzyka rozwoju oporności. W niniejszej pracy opisano główne założenia rozprawy doktorskiej dr inż. Aleksandry Tymoszewskiej, której celem była identyfikacja mechanizmów działania i rozwoju oporności na bakteriocyny klasy II u bakterii Gram-dodatnich. Wykorzystując jako model badawczy komórki bakterii Lactococcus lactis, zbadano dwie grupy bakteriocyn: (i) garwicyny Q, A, B i C, oraz BacSJ; oraz (ii) bakteriocyny aureocyno A53 (AurA53)- i enterocyno L50 (EntL50)- podobne. Pokazano, że bakteriocyny grupy (i) rozpoznają komórki wrażliwe i tworzą pory wewnątrz błony komórkowej bakterii wykorzystując specyficzny receptor, system mannozo-specyficznej fosfotransferazy (Man-PTS), a także, że bakterie wrażliwe nabywają oporność na badane bakteriocyny poprzez modyfikacje struktury Man-PTS. Z kolei nabywanie oporności na bakteriocyny grupy (ii), tworzące pory bezpośrednio w błonie komórkowej bakterii, zachodzi poprzez zmiany w strukturze ściany i błony komórkowej wywołane zmianami w ekspresji białek zaangażowanych w metabolizm lipidów lub stanowiących elementy systemu regulacyjnego YsaCB-KinG-LlrG. Otrzymane wyniki rzucają nowe światło na dotychczasowe poglądy dotyczące mechanizmów działania bakteriocyn i szeroko otwierają możliwości ich dalszych badań

ClaR—a novel key regulator of cellobiose and lactose metabolism in Lactococcus lactis IL1403

In a number of previous studies, our group has discovered an alternative pathway for lactose utilization in Lactococcus lactis that, in addition to a sugar-hydrolyzing enzyme with both P-β-glucosidase and P-β-galactosidase activity (BglS), engages chromosomally encoded components of cellobiose-specific PTS (PTSCel-Lac), including PtcA, PtcB, and CelB. In this report, we show that this system undergoes regulation via ClaR, a novel activator protein from the RpiR family of transcriptional regulators. Although RpiR proteins are widely distributed among lactic acid bacteria, their roles have yet to be confirmed by functional assays. Here, we show that ClaR activity depends on intracellular cellobiose-6-phosphate availability, while other sugars such as glucose or galactose have no influence on it. We also show that ClaR is crucial for activation of the bglS and celB expression in the presence of cellobiose, with some limited effects on ptcA and ptcB activation. Among 190 of carbon sources tested, the deletion of claR reduces L. lactis growth only in lactose- and/or cellobiose-containing media, suggesting a narrow specificity of this regulator within the context of sugar metabolism

The LiaFSR-LiaX System Mediates Resistance of Enterococcus faecium to Peptide Antibiotics and to Aureocin A53- and Enterocin L50-Like Bacteriocins

Multidrug-resistant Enterococcus faecium strains are currently a leading cause of difficult-to-treat nosocomial infections. The emerging resistance of enterococci to last-resort antibiotics, such as daptomycin, prompts a search for alternative antimicrobials. Aureocin A53- and enterocin L50-like bacteriocins are potent antimicrobial agents that form dapto�mycin-like cationic complexes and have a similar cell envelope-targeting mechanism of action, suggesting their potential as next-generation antibiotics. However, to ensure their safe use, the mechanisms of resistance to these bacteriocins and cross-resistance to anti�biotics need to be well understood. Here, we investigated the genetic basis of E. faecium’s resistance to aureocin A53- and enterocin L50-like bacteriocins and compared it with that to antibiotics. First, we selected spontaneous mutants resistant to the bacteriocin BHT-B and identified adaptive mutations in the liaFSR-liaX genes encoding the LiaFSR stress response regulatory system and the daptomycin-sensing protein LiaX, respectively. We then demonstrated that a gain-of-function mutation in liaR increases the expression of liaFSR, liaXYZ, cell wall remodeling-associated genes, and hypothetical genes involved in protection against various antimicrobials. Finally, we showed that adaptive mutations or overexpression of liaSR or liaR alone results in cross-resistance to other aureocin A53- and enterocin L50-like bacteriocins, as well as antibiotics targeting specific components of the cell envelope (daptomycin, ramoplanin, gramicidin) or ribosomes (kanamycin and gentamicin). Based on the obtained results, we concluded that activation of the LiaFSR�mediated stress response confers resistance to peptide antibiotics and bacteriocins via a cascade of reactions, eventually leading to cell envelope remodeling

Subclass IId bacteriocins targeting mannose phosphotransferase system—Structural diversity and implications for receptor interaction and antimicrobial activity

The bacterial mannose phosphotransferase system (Man-PTS) mediates uptake of selected monosaccharides. Simultaneously, it is a receptor for diverse bacteriocins such as subclass IIa pediocin-like bacteriocins and some subclass IId ones (garvicins ABCQ, lactococcins ABZ, BacSJ, ubericin K, and angicin). So far, no attempt has been made to categorize this ever-expanding group of bacteriocins. Here, we identified Man-PTS as a receptor for a number of previously uncharacterized bacteriocins, and demonstrated that they all belong to a large family of Man-PTS-binding nonpediocin-like peptides, providing new insights into their structure and function. Based on amino acid sequence similarities between members of this family, we propose their classification into five groups. This classification conveniently distinguishes bacteriocins with specific structures and properties regarding their spectrum of antimicrobial activity and pattern of interaction with Man-PTS. With respect to the latter, we indicate individual amino acid residues or regions of Man-PTS and the bacteriocin responsible for their interaction. In Man-PTS, these residues localize to the exterior of the transport complex, specifically the extracellular loop of the so-called Vmotif domain-containing regions γ and/or γ+, and to the interior of the transport complex, specifically the interface between the Core and Vmotif domains. Finally, we propose that while the bacteriocins from separate groups display specific binding patterns to Man-PTS, the general mechanism of their interaction with the receptor is universal despite significant differences in their predicted structures, i.e. after initial docking on the bacterial cell through an interaction with the Man-PTS regions γ and/or γ+, they pull away its Core and Vmotif from one another to form a pore across the membrane

BacSJ—Another Bacteriocin with Distinct Spectrum of Activity that Targets Man-PTS

Lactic acid bacteria produce diverse antimicrobial peptides called bacteriocins. Most bacteriocins target sensitive bacteria by binding to specific receptors. Although a plethora of bacteriocins have been identified, for only a few of them the receptors they recognize are known. Here, we identified permease IIC and surface protein IID, two membrane subunits of the mannose-specific quaternary phosphotransferase system (Man-PTS), as a receptor for BacSJ, a subclass IId bacteriocin produced by Lactobacillus paracasei subsp. paracasei BGSJ2-8. BacSJ shares 45% identity with another Man-PTS binding bacteriocin, garvicin Q (GarQ). Similarly to GarQ, BacSJ has a relatively broad activity spectrum acting against several Gram-positive bacteria, such as Lactococcus lactis and Listeria monocytogenes, harboring fairly similar Man-PTSs, but not against Lactococcus garvieae. To identify specific Man-PTS amino acids responsible for the L.lactis sensitivity to BacSJ, and thus likely involved in the interaction with this bacteriocin, we generated eight independent BacSJ resistant L.lactis mutants harboring five distinct missense mutations in the ptnC or ptnD genes encoding the IIC and IID subunits. Concurrently with the resistance to BacSJ, the mutants efficiently utilized mannose as a carbon source, which indicated functionality of their mutated Man-PTS. The amino acid substitutions in the mutants localized to the intracellular region of the IIC permease or to the extracellular parts of IID. This localization coincides with regions targeted by GarQ and some other Man-PTS-binding garvicins, pointing to similarities between all these bacteriocins in the mechanism of their interaction with Man-PTS. During the attack by these bacteriocins, subunits IID and IIC are assumed to function sequentially as a docking and an entry module allowing the toxic peptide to bind the cell and then open the pore. However, since not all of the BacSJ-resistant mutants exhibited cross-resistance to GarQ, we propose that BacSJ interacts with Man-PTS in a manner slightly different from that of GarQ

Whole-genome sequencing and characterization of human fecal isolate Lacticaseibacillus casei LC130 from NORDBIOTIC collection

We report the complete genome sequence of Lacticaseibacillus casei LC130, isolated from a healthy human fecal sample and part of the NORDBIOTIC collection. The 2.969 Mb genome of LC130 includes genes potentially involved in lactose metabolism and the production of bacteriocins, peptidases, and polyamines, suggesting potential health benefits. KEYWORDS probiotics, prohealth effects, bacteriocins, gluten-degrading peptidases, polyamines, lactose metabolism, lactic acid bacteria, fecal human isolat

Complete genome sequence of the probiotic Lacticaseibacillus paracasei LPC100 strain from the NORDBIOTIC collection isolated from a human fecal sample

We report the genome sequence of the human fecal isolate Lacticaseibacillus paracasei LPC100 from the NORDBIOTIC collection, comprising a 3.075 Mb chromosome and three plasmids (61 kb, 12 kb, and 7 kb). Genetic content reveals the strain’s beneficial features—complete lactose metabolic pathway, potential production of bacteriocins, and short-chain fatty acids

A smelly business: microbiology of Adélie penguin guano (Point Thomas rookery, Antarctica)

Adélie penguins (Pygoscelis adeliae) are the most numerous flightless bird group breeding in coastal areas of Maritime and Continental Antarctica. Their activity leaves a mark on the land in the form of large guano deposits. This guano is an important nutrient source for terrestrial habitats of ice-free Antarctic areas, most notably by being the source of ammonia vapors which feed the surrounding grass, lichen and algae communities. Although investigated by researchers, the fate of the guano-associated microbial community and its role in decomposition processes remain vague. Therefore, by employing several direct community assessment methods combined with a broad culture-based approach we provide data on bacterial numbers, their activity and taxonomic affiliation in recently deposited and decayed Adélie penguin guano sampled at the Point Thomas rookery in Maritime Antarctica (King George Island). Our research indicates that recently deposited guano harbored mostly bacteria of penguin gut origin, presumably inactive in cold rookery settings. This material was rich in mesophilic enzymes active also at low temperatures, likely mediating early stage decomposition. Fresh guano colonization by environmental bacteria was minor, accomplished mostly by ammonia scavenging Jeotgalibaca sp. cells. Decayed guano contained 10-fold higher bacterial numbers with cold-active enzymes dominating the samples. Guano was colonized by uric-acid degrading and lipolytic Psychrobacter spp. and proteolytic Chryseobacterium sp. among others. Several spore-forming bacteria of penguin gut origin persisted in highly decomposed material, most notably uric-acid fermenting members of the Gottschalkiaceae family

Microbial community changes along the Ecology Glacier ablation zone (King George Island, Antarctica)

In recent years glacial surfaces have received much attention as microbial habitats of diverse photoautotrophic and heterotrophic cells. Supraglacial ecosystems are annually covered and uncovered by snow. The aim of this study was to investigate the microbial community response to changing environmental conditions in a transect following the receding snow line on the surface of Ecology Glacier (King George Island, Antarctica). Parameters of surface ice and cryoconite holes included chemical composition of ice and sediment, Bacteria diversity by denaturating gradient gel electrophoresis (DGGE), microbial functional diversity (Biolog Ecoplates), and microbial counts (epifluorescence microscopy, colony forming units - CFU). Data demonstrated profound differences between surface ice and cryoconite holes. Changing environmental factors along the transect influenced composition and abundance of the microbiocenosis in both habitat types. Several parameters correlated positively with distance from the glacier edge, including the cell morphotype Shannon Index, chlorophyll a, nitrogen and seston concentrations. Suspended solids content positively correlated with microbial 2 abundance and diversity. Nitrogen and phosphorus were limiting factors of microbial growth as amounts of organic nitrogen and phosphorus positively correlated with the cell numbers, fission rates and photoautotroph contribution. Our findings indicate that microbial community shows a response in terms of abundance and diversity to exposure of the glacial surface as snow-cover melts. To our knowledge this is the first study to recognize a microbial development pattern on a glacier surface in connection with the receding snow line. This may help better understand variability within supraglacial habitats, correct sampling procedures and inform biocenotic development models