44 research outputs found
Studies on Staphylococcus epidermidis biofilm formation and the bacterial interaction with the human cathelicidin antimicrobial peptide LL-37
The long-term use of central venous catheters for delivering nutrients and drugs in preterm neonates has been related to nosocomial infections. The majority of late-onset sepsis in very preterm infants (<28 gestational weeks) are caused by Gram positive bacteria. Coagulase- negative staphylococci (CoNS) are responsible for almost the half of these cases. Staphylococcus epidermidis is the most prevalent bacteria identified from CoNS bacteraemia and biofilm production is found to be the main determinant of persistent infection.
The major host defense peptide LL-37 is the only cathelicidin antimicrobial peptide that exists in humans. The peptide is broadly distributed in the human body and possesses several additional functions related to host defense. As a cathionic peptide, it interacts with the negatively charged bacterial surface. LL-37 is shown to inhibit biofilm formation and regulates biofilm-associated gene expression in Pseudomonas aeruginosa in vitro.
In Paper I, we showed that S. epidermidis strains obtained from bloodstream infection in preterm infants had different characteristics than the skin strains isolated from healthy term neonates. The blood isolates were equipped with an invasive genetic element IS256 and showed higher antimicrobial resistance compared with the skin isolates. However, vancomycin resistance was not detected among any of the strains. We also observed short and long filament- like structures on the cell surface of S. epidermidis. These filaments were involved in the attachment to the catheter surface and also in cell to cell attachment and/or communication.
Our in vitro studies in Paper II and Paper III, revealed that physiological LL-37 peptide concentrations, below those that kill or inhibit growth of the free-floating bacteria, inhibited S. epidermidis attachment and biofilm formation on abiotic surfaces. In Paper III, we observed that the peptide regulates genes involved in the biofilm formation.
In Paper IV, we found that the circulating serum level of hCAP18/LL-37 was similar in preterm and term neonates at birth and both the inactive protein and the active peptide were detectable independent of the gestational time. We observed positive correlation between maternal and infant peptide concentration. This may indicate that the peptide passes over early during pregnancy.
In summary, our work revealed that S. epidermidis strains that cause bloodstream infection in preterm infants are more virulent compared with skin strains in term neonates. Physiological concentration of the human cathionic peptide LL-37 had inhibitory effect on S. epidermidis biofilm formation by regulating biofilm genes. The similar LL-37 peptide concentration in preterm and term infantsâ blood might suggest that these neonateâs vulnerability is not connected to the lower antimicrobial peptide level at birth
Young L2-learners' meaning-making in engaging in computer-assisted language learning
[EN] This study explores how newly arrived young students created meaning, communicated, and expressed themselves using digital technology in the subject of Swedish as a second language (SSL). The qualitative case study presented in this article focuses on how the orchestration of teaching contributed to opportunities for digital meaning-making in the SSL subject in four classrooms at three schools in a city in Sweden. The notion of language as being fluid, which involves a critical approach to languages as separable entities, considers linguistic and embodied meaning-making, including digital technology, in social processes. This approach recognizes the roles of technology and digital meaning-making in young studentsâ second language acquisition. Moreover, technological innovations facilitate immediate and accessible communication. In todayâs language studies, ethnicity only is not considered an adequate focus of analysis. Furthermore, the meaning-making practices of newly arrived primary school-aged students remain under-investigated. In the present study, data collected in classroom observations and teacher interviews revealed three themes regarding the studentsâ utilization of digital technology to develop their multilingual skills. One insight was that the newly arrived students used digital technology strategically when they engaged in meaning-making activities with peers and teachers. When the students took the initiative in computer-assisted language learning, they displayed agency in meaning-making by being their own architects. The findings of this research provided insights into how the orchestration of teaching in Swedish as a second language to newly arrived students affects their opportunities to use multilingualism in meaning-making while employing digital technology.Hell, A.; Godhe, A.; WennĂĽs Brante, E. (2021). 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Potential for improvement of population diet through reformulation of commonly eaten foods
Food reformulation: Reformulation of foods is considered one of the key options to achieve population nutrient goals. The compositions of many foods are modified to assist the consumer bring his or her daily diet more in line with dietary recommendations. Initiatives on food reformulation: Over the past few years the number of reformulated foods introduced on the European market has increased enormously and it is expected that this trend will continue for the coming years. Limits to food reformulation: Limitations to food reformulation in terms of choice of foods appropriate for reformulation and level of feasible reformulation relate mainly to consumer acceptance, safety aspects, technological challenges and food legislation. Impact on key nutrient intake and health: The potential impact of reformulated foods on key nutrient intake and health is obvious. Evaluation of the actual impact requires not only regular food consumption surveys, but also regular updates of the food composition table including the compositions of newly launched reformulated foods
Strigolactone- and Karrikin-Independent SMXL Proteins Are Central Regulators of Phloem Formation
Plant stem cell niches, the meristems, require long-distance transport of energy metabolites and signaling molecules along the phloem tissue. However, currently it is unclear how specification of phloem cells is controlled. Here we show that the genes SUPPRESSOR OF MAX2 1-LIKE3 (SMXL3), SMXL4, and SMXL5 act as cell-autonomous key regulators of phloem formation in Arabidopsis thaliana. The three genes form an uncharacterized subclade of the SMXL gene family that mediates hormonal strigolactone and karrikin signaling. Strigolactones are endogenous signaling molecules regulating shoot and root branching [1] whereas exogenous karrikin molecules induce germination after wildfires [2]. Both activities depend on the F-box protein and SCF (Skp, Cullin, F-box) complex component MORE AXILLARY GROWTH2 (MAX2) [3-5]. Strigolactone and karrikin perception leads to MAX2-dependent degradation of distinct SMXL protein family members, which is key for mediating hormonal effects [6-12]. However, the nature of events immediately downstream of SMXL protein degradation and whether all SMXL proteins mediate strigolactone or karrikin signaling is unknown. In this study we demonstrate that, within the SMXL gene family, specifically SMXL3/4/5 deficiency results in strong defects in phloem formation, alteredsugar accumulation, and seedling lethality. By comparing protein stabilities, we show that SMXL3/4/5 proteins function differently to canonical strigolactone and karrikin signaling mediators, although being functionally interchangeable with those under low strigolactone/karrikin signaling conditions. Our observations reveal a fundamental mechanism of phloem formation and indicate that diversity of SMXL protein functions is essential for a steady fuelling of plant meristems.Peer reviewe
Eating habits and weight status in Finnish adolescents
Objective: To investigate the association between eating habits and weight status in adolescents in Finland. Design: Cross-sectional study. Setting: The Finnish Health in Teens (Fin-HIT) study is a cohort study conducted in adolescents attending third to sixth grade in 496 schools in forty-four municipalities in Southern, Middle and Northern Finland in 2011-2014. Participants: Analyses included 10 569 adolescents from the Fin-HIT study aged 9-14 years (5005 boys and 5564 girls). Adolescents were categorized by their eating habits: healthy eaters (44 center dot 1 %; n 4661), unhealthy eaters (12 center dot 3 %; n 1298), and fruit and vegetable avoiders (43 center dot 6 %; n 4610); and they were grouped into weight status: underweight (11 center dot 1 %), normal weight (73 center dot 6 %) and excess weight (15 center dot 3 %). Results: We found an increased risk of underweight in fruit and vegetable avoiders (OR = 1 center dot 28; 95 % CI 1 center dot 12, 1 center dot 46). An irregular breakfast pattern showed an inverse association with underweight (OR = 0 center dot 70; 95 % CI 0 center dot 59, 0 center dot 84) and an increased risk of excess weight (OR = 1 center dot 56; 95 % CI 1 center dot 37, 1 center dot 77) compared with a regular breakfast pattern. An irregular dinner pattern was inversely associated with underweight (OR = 0 center dot 83; 95 % CI 0 center dot 69, 0 center dot 99) compared with a regular dinner pattern. Conclusions: Avoiding fruits and vegetables and following irregular breakfast and dinner patterns were associated with underweight and excess weight in adolescents.Peer reviewe
Serodiagnosis of Echinococcus spp. Infection: Explorative Selection of Diagnostic Antigens by Peptide Microarray
Crude or purified, somatic or metabolic extracts of native antigens are routinely used for the serodiagnosis of human helminthic infections. These antigens are often cross-reactive, i.e., recognized by sera from patients infected with heterologous helminth species. To overcome limitations in antigen production, test sensitivity and specificity, chemically synthesized peptides offer a pure and standardized alternative, provided they yield acceptable operative characteristics. Ongoing genome and proteome work create new resources for the identification of antigens. Making use of the growing amount of genomic and proteomic data available in public databases, we tested a bioinformatic procedure for the selection of potentially antigenic peptides from a collection of protein sequences including conceptually translated nucleotide sequence data of Echinococcus multilocularis and E. granulosus (Plathyhelminthes, Cestoda). The in silico selection was combined with high-throughput screening of peptides on microarray and systematic validation of reactive candidates in enzyme-linked immunosorbent assay. Our study proved the applicability of this approach for selection of peptide antigens with good diagnostic characteristics. Our results suggested the pooling of several peptides to reach a high level of sensitivity required for reliable immunodiagnosis
Immunohistochemical Assessment of the Tumour-Associated Epitopes CD44v6 and E48 in Tumour-Free Lymph Nodes from Patients with Squamous Cell Carcinoma in the Head-Neck Region
We examined immunohistochemically 370 tumourâfree lymph nodes from 41 patients with a head and neck squamous cell carcinoma (HNSCC) to clarify whether the tumourâassociated epitopes CD44v6 and E48 are suitable for adjuvant postoperative immunotherapy. All the positively immunostained cells found were single cells