The putative thiosulfate sulfurtransferases PspE and GlpE contribute to virulence of <em>Salmonella</em> Typhimurium in the mouse model of systemic disease.

The phage-shock protein PspE and GlpE of the glycerol 3-phosphate regulon of Salmonella enterica serovar Typhimurium are predicted to belong to the class of thiosulfate sulfurtransferases, enzymes that traffic sulfur between molecules. In the present study we demonstrated that the two genes contribute to S. Typhimurium virulence, as a glpE and pspE double deletion strain showed significantly decreased virulence in a mouse model of systemic infection. However, challenge of cultured epithelial cells and macrophages did not reveal any virulence-associated phenotypes. We hypothesized that their contribution to virulence could be in sulfur metabolism or by contributing to resistance to nitric oxide, oxidative stress, or cyanide detoxification. In vitro studies demonstrated that glpE but not pspE was important for resistance to H(2)O(2). Since the double mutant, which was the one affected in virulence, was not affected in this assay, we concluded that resistance to oxidative stress and the virulence phenotype was most likely not linked. The two genes did not contribute to nitric oxid stress, to synthesis of essential sulfur containing amino acids, nor to detoxification of cyanide. Currently, the precise mechanism by which they contribute to virulence remains elusive

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The in vitro redundant enzymes PurN and PurT are both essential for systemic infection of mice in Salmonella enterica serovar Typhimurium

Metabolic enzymes show a high degree of redundancy, and for that reason they are generally ignored in searches for novel targets for anti-infective substances. The enzymes PurN and PurT are redundant in vitro in Salmonella enterica serovar Typhimurium, in which they perform the third step of purine synthesis. Surprisingly, the results of the current study demonstrated that single-gene deletions of each of the genes encoding these enzymes caused attenuation (competitive infection indexes [CI] of <0.03) in mouse infections. While the ΔpurT mutant multiplied as fast as the wild-type strain in cultured J774A.1 macrophages, net multiplication of the ΔpurN mutant was reduced approximately 50% in 20 h. The attenuation of the ΔpurT mutant was abolished by simultaneous removal of the enzyme PurU, responsible for the formation of formate, indicating that the attenuation was related to formate accumulation or wasteful consumption of formyl tetrahydrofolate by PurU. In the process of further characterization, we disclosed that the glycine cleavage system (GCV) was the most important for formation of C(1) units in vivo (CI = 0.03 ± 0.03). In contrast, GlyA was the only important enzyme for the formation of C(1) units in vitro. The results with the ΔgcvT mutant further revealed that formation of serine by SerA and further conversion of serine into C(1) units and glycine by GlyA were not sufficient to ensure C(1) formation in S. Typhimurium in vivo. The results of the present study call for reinvestigations of the concept of metabolic redundancy in S. Typhimurium in vivo

Matematikkvansker – Hvilke tiltak kan fremme inkludering? En kvalitativ intervjuundersøkelse blant utvalgte matematikklærere på mellomtrinnet.

Masteroppgave i tilpassa opplæring - 202

Adaptation and validation of the short version WHOQOL-HIV in Ethiopia

BACKGROUND: Quality of life of patients is an important element in the evaluation of outcome of health care, social services and clinical trials. The WHOQOL instruments were originally developed for measurement of quality of life across cultures. However, there were concerns raised about the cross-cultural equivalence of the WHOQOL-HIV when used among people with HIV in Ethiopia. Therefore, this study aimed at adapting the WHOQOL-HIV bref for the Ethiopian setting. METHODS: A step-wise adaptation of the WHOQOL-HIV bref for use in Ethiopia was conducted to produce an Ethiopian version—WHOQOL-HIV-BREF-Eth. Semantic and item equivalence was tested on 20 people with HIV. One hundred people with HIV were interviewed to test for measurement equivalence (known group validity and internal consistency) of the WHOQOL-HIV-BREF-Eth. Confirmatory factor analysis was conducted using data from 348 people with HIV who were recruited from HIV clinics. RESULTS: In the process of adaptation, new items of relevance to the context were added while seven items were deleted because of problems with acceptability and poor psychometric properties. The Cronbach’s α for the final tool with twenty-seven items WHOQOL-HIV-BREF-Eth was 0.93. All six domains discriminated well between symptomatic and asymptomatic people with HIV (p < 0.001). Using confirmatory factor analysis, a second order factor structure with six first order indicator factors demonstrated moderate fit to the data ((χ(2) = 627.75; DF = 259; p < 0.001), CFI = 0.82, TLI = 0.77 and RMSEA = 0.064). CONCLUSION: The WHOQOL-HIV-BREF-Eth has been shown to be a valid measure of quality of life for use in clinical settings among people with HIV in Ethiopia

The competence and warmth of Thai students’ attitudes towards varieties of English: the effect of gender and perceptions of L1 diversity

Previous language attitude research indicates that presenting speech forms allows listeners to index information about and attach social meaning to the perceived group(s) of speakers. Despite the volume of research undertaken elsewhere in Asia, there appear to be no in-depth studies investigating Thai nationals’ evaluations of specific varieties of English speech. This large-scale study examines 204 Thai university students’ attitudes towards forms of UK, US, Japanese, Chinese, Thai and Indian English, provided by highly proficient female speakers. The study also examines the extent to which Thai students’ perceptions of linguistic diversity in their L1 and their gender affect their attitudes. Multivariate analysis demonstrated UK, US and Thai English speech was ranked significantly higher than other Asian forms of English, for competence and warmth, attitudinal dimensions consistent with recent findings in social cognition. Further analysis indicated females and those most positive towards L1 variation expressed significantly higher levels of ingroup loyalty towards Thai English speakers. The findings are compared and contrasted with the results of equivalent studies undertaken in other Asian contexts and, given recent cutting-edge research in social cognition confirming the primacy of warmth judgements, calls for language attitude researchers to consider speaker warmth ratings more fully in future studies

Putrescine biosynthesis and export genes are essential for normal growth of avian pathogenic Escherichia coli

[Background] Avian pathogenic Escherichia coli (APEC) is the infectious agent of a wide variety of avian diseases, which causes substantial economic losses to the poultry industry worldwide. Polyamines contribute to the optimal synthesis of nucleic acids and proteins in bacteria. The objectives of this study were to investigate; i) whether APEC E. coli encodes the same systems for biosynthesis and uptake as described for E. coli K12 and ii) the role of polyamines during in vitro growth of an avian pathogenic E. coli strain (WT-ST117- O83:H4T).[Results] Following whole genome sequencing, polyamine biosynthesis and export genes present in E. coli MG1655 (K-12) were found to be identical in WT-ST117. Defined mutants were constructed in putrescine and spermidine biosynthesis pathways (ΔspeB, ΔspeC, ΔspeF, ΔspeB/C and ΔspeD/E), and in polyamines transport systems (ΔpotE, ΔyeeF, ΔpotABCD and ΔpotFGHI). Contrary to what was observed for MG1655, the ΔpotE-ST117 mutant was growth attenuated, regardless of putrescine supplementation. The addition of spermidine or orthinine restored the growth to the level of WT-ST117. Growth attenuation after induction of membrane stress by SDS suggested that PotE is involved in protection against this stress. The ΔspeB/C-ST117 mutant was also growth attenuated in minimal medium. The addition of putrescine or spermidine to the media restored growth rate to the wild type level. The remaining biosynthesis and transport mutants showed a growth similar to that of WT-ST117. Analysis by Ultra-High Performance Liquid Chromatography revealed that the ΔspeB/C mutant was putrescine-deficient, despite that the gene speF, which is also involved in the synthesis of putrescine, was expressed.[Conclusions] Deletion of the putrescine transport system, PotE, or the putrescine biosynthesis pathway genes speB/C affected in vitro growth of APEC (ST117- O83:H4) strain, but not E. coli MG1655, despite the high similarity of the genetic make-up of biosynthesis and transport genes. Therefore, blocking these metabolic reactions may be a suitable way to prevent APEC growth in the host without disturbing the commensal E. coli population.Priscila R. Guerra was supported by a scholarship from CAPES – Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of Brazil. This study received financial support from Spanish Ministry of Economy, Industry and Competitiveness (AGL2013–45431-R and AGL2016–78708-R), and from the Danish Council for Independent Research (Technology and Production), grant number DFF – 4184-00050. The sponsors had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe