| 1. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
-
Direct repeat-mediated deletion of a type IV pilin gene results in major virulence attenuation of Francisella tularensis
- 2006
-
Ingår i: Molecular Microbiology. - : Wiley-Blackwell. - 0950-382X .- 1365-2958. ; 59:6, s. 1818-1830
-
Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis, the causative agent of tularaemia, is a highly infectious and virulent intracellular pathogen. There are two main human pathogenic subspecies, Francisella tularensis ssp. tularensis (type A), and Francisella tularensis ssp. holarctica (type B). So far, knowledge regarding key virulence determinants is limited but it is clear that intracellular survival and multiplication is one major virulence strategy of Francisella. In addition, genome sequencing has revealed the presence of genes encoding type IV pili (Tfp). One genomic region encoding three proteins with signatures typical for type IV pilins contained two 120 bp direct repeats. Here we establish that repeat-mediated loss of one of the putative pilin genes in a type B strain results in severe virulence attenuation in mice infected by subcutaneous route. Complementation of the mutant by introduction of the pilin gene in cis resulted in complete restoration of virulence. The level of attenuation was similar to that of the live vaccine strain and this strain was also found to lack the pilin gene as result of a similar deletion event mediated by the direct repeats. Presence of the pilin had no major effect on the ability to interact, survive and multiply inside macrophage-like cell lines. Importantly, the pilin-negative strain was impaired in its ability to spread from the initial site of infection to the spleen. Our findings indicate that this putative pilin is critical for Francisella infections that occur via peripheral routes.
|
|
| 2. |
- Egge-Jacobsen, Wolfgang, et al.
(författare)
-
O-Linked glycosylation of the PilA pilin protein of francisella tularensis : identification of the endogenous protein-targeting oligosaccharyltransferase and characterization of the native oligosaccharide
- 2011
-
Ingår i: Journal of Bacteriology. - Baltimore : Williams & Wilkins. - 0021-9193 .- 1098-5530. ; 193:19, s. 5487-5497
-
Tidskriftsartikel (refereegranskat)abstract
- Findings from a number of studies suggest that the PilA pilin proteins may play an important role in the pathogenesis of disease caused by species within the genus Francisella. As such, a thorough understanding of PilA structure and chemistry is warranted. Here, we definitively identified the PglA protein-targeting oligosaccharyltransferase by virtue of its necessity for PilA glycosylation in Francisella tularensis and its sufficiency for PilA glycosylation in Escherichia coli. In addition, we used mass spectrometry to examine PilA affinity purified from Francisella tularensis subsp. tularensis and F. tularensis subsp. holarctica and demonstrated that the protein undergoes multisite, O-linked glycosylation with a pentasaccharide of the structure HexNac-HexHex-HexNac-HexNac. Further analyses revealed microheterogeneity related to forms of the pentasaccharide carrying unusual moieties linked to the distal sugar via a phosphate bridge. Type A and type B strains of Francisella subspecies thus express an O-linked protein glycosylation system utilizing core biosynthetic and assembly pathways conserved in other members of the proteobacteria. As PglA appears to be highly conserved in Francisella species, O-linked protein glycosylation may be a feature common to members of this genus.
|
|
| 3. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
-
Hfq, a novel pleiotropic regulator of virulence-associated genes in Francisella tularensis
- 2009
-
Ingår i: Infection and Immunity. - : American society for microbiology. - 0019-9567 .- 1098-5522. ; 77:5, s. 1866-80
-
Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is a highly infectious pathogen that infects animals and humans, causing tularemia. The ability to replicate within macrophages is central for virulence and relies on expression of genes located in the Francisella pathogenicity island (FPI), as well as expression of other genes. Regulation of FPI-encoded virulence gene expression in F. tularensis involves at least four regulatory proteins and is not fully understood. Here we studied the RNA-binding protein Hfq in F. tularensis and particularly the role that it plays as a global regulator of gene expression in stress tolerance and pathogenesis. We demonstrate that Hfq promotes resistance to several cellular stresses (including osmotic and membrane stresses). Furthermore, we show that Hfq is important for the ability of the F. tularensis vaccine strain LVS to induce disease and persist in organs of infected mice. We also demonstrate that Hfq is important for stress tolerance and full virulence in a virulent clinical isolate of F. tularensis, FSC200. Finally, microarray analyses revealed that Hfq regulates expression of numerous genes, including genes located in the FPI. Strikingly, Hfq negatively regulates only one of two divergently expressed putative operons in the FPI, in contrast to the other known regulators, which regulate the entire FPI. Hfq thus appears to be a new pleiotropic regulator of virulence in F. tularensis, acting mostly as a repressor, in contrast to the other regulators identified so far. Moreover, the results obtained suggest a novel regulatory mechanism for a subset of FPI genes.
|
|
| 4. |
|
|
| 5. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
-
The type IV pilin, PilA, is required for full virulence of Francisella tularensis subspecies tularensis
-
Annan publikation (populärvet., debatt m.m.)abstract
- Background: All four Francisella tularensis subspecies possess gene clusters with potential to express type IV pili (Tfp). These clusters include putative pilin genes, as well as pilB, pilC and pilQ, required for secretion and assembly of Tfp. A hallmark of Tfp is the ability to retract the pilus upon surface contact, a property mediated by the ATPase PilT. Interestingly, out of the two major human pathogenic subspecies only the highly virulent type A strains have a functional pilT gene.Results: In a previous study, we were able to show that one pilin gene, pilA, was essential for virulence of a type B strain in a mouse infection model. In this work we have examined the role of several pilin genes in the virulence of the pathogenic type A strain SCHU S4. pilA, pilC, pilQ, and pilT were mutated by in-frame deletion mutagenesis. Interestingly, when mice were infected with a mixture of each mutant strain and the wild-type strain, the pilA, pilC and pilQ mutants were out-competed, while the pilT mutant was equally competitive as the wild-type.Conclusions: This suggests that expression and surface localisation of PilA contribute to virulence in the highly virulent type A strain, while PilT was dispensable for virulence in the mouse infection model.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Forslund, Kerstin, et al.
(författare)
-
Acute chest pain emergencies : spouses' prehospital experiences
- 2008
-
Ingår i: International emergency nursing. - : Elsevier BV. - 1878-013X .- 1755-599X. ; 16:4, s. 233-240
-
Tidskriftsartikel (refereegranskat)abstract
- The call to the Emergency Medical Dispatch Centre is often a person's first contact with the health-care system in cases of acute illness or injury and acute chest pain is a common reason for calling. The aim was to illuminate how spouses to persons with acute chest pain experienced the alarm situation, the emergency call and the prehospital emergency care. Interviews were conducted with nineteen spouses. A phenomenological-hermeneutic approach was used for the analyses. The themes responsibility and uneasiness emerged as well as an overall theme of aloneness. Being a spouse to a person in need of acute medical and nursing assistance was interpreted as "Being responsible and trying to preserve life" and "Being able to manage the uneasiness and having trust in an uncertain situation." When their partners' life was at risk the spouses were in an escalating spiral of worry, uncertainty, stress, fear of loss, feeling of loneliness and desperation. They had to manage emotional distress and felt compelled to act to preserve life, a challenging situation.
|
|
| 9. |
- Forslund, Kerstin, 1953-
(författare)
-
Challenges in prehospital emergency care : patient, spouse and personnel perspectives
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prehospital emergency care (PEC) with the emergency call to the Emergency Medical Dispatch (EMD) centre is an essential part of the health-care system. It is important to obtain knowledge about the links in the PEC chain from the perspectives of those providing the service and those receiving it. The overall aim of this thesis was to describe the challenges surrounding PEC based on the experiences of patients, spouses and personnel. A qualitative descriptive design was used in the five papers included. The data analysis methods were phenomenological-hermeneutics (I–III), qualitative content analysis (IV–V) and descriptive statistics (V). Interviews with thirteen patients who had called the EMD-centre due to acute chest pain (I) revealed a general satisfaction with PEC. They were aware of the number to call in an emergency but were uncertain when to call. The potentially life threatening emergency situation was marked by vulnerability and dependency and was fraught with pain, fear and a sense of aloneness. An overall theme of aloneness emerged from the interviews with nineteen spouses who had placed an emergency call for their husband or wife that was experiencing acute chest pain (II). The challenges in being a spouse to a person in need of PEC were associated with: “Being responsible and trying to preserve life” and “Being able to manage the uneasiness and feel trust in an uncertain situation”. The spouses were in an escalating spiral of aloneness, worry, uncertainty, stress, fear of loss and desperation. Interviews with sixteen emergency operators dealt with situations they considered difficult to deal with and their reflections on how they managed such situations (III). Uncertainty, communication difficulties and insufficient resources characterized those situations. Skills, knowledge, experience, as well as personal qualities such as sensitivity, self-insight, empathy and intuition were regarded as important when handling them. Interviews with four nurses and fifteen emergency operators related to their experiences of working together for two years at an EMD-centre were conducted after the nurses were added to the EMD-centre to increase medical and nursing competence (IV). Initial frustration and scepticism changed to positive experiences with improved cooperation and service. The nurses voiced difficulties dealing with the more medically urgent calls and the emergency operators with the more complicated and diffuse medical cases. A total of 336 questionnaires related to alarms involving acute chest pain and given the highest priority by the emergency operator were collected in a study aimed at describing the ambulance personnel’s perceptions of the quality of the information received from the EMD-centre (V). The ambulance personnel perceived most of the information such as patient assessment, condition, history, preparedness and in particular pain status to be of high quality. In summary: In PEC there is many interdependent complexities that present demands and challenges to the actors involved (I–V). In general those who received emergency assistance from PEC were satisfied, but the margins between success and failure are small. Risks for errors exist throughout the PEC chain and time poses a challenge. Understanding is crucial for all involved, and the same situation can be experienced differently. Challenges inherent in PEC are the communication problems, unpredictability and uniqueness along with daring to be in the acute situation and dealing with a sense of aloneness, uncertainty and dependency. The personnel that do not have the ability to see the person they are helping are even more challenged. Important attributes for PEC personnel are caring attitudes, personal skills, experiences and professional knowledge. PEC personnel have the authority and power to act and make decisions, in which responsibility, sensitivity, and human dignity must be addressed. Lives are saved with PEC despite all the challenges and possibilities for error, such as those that exist between the different actors. It is vital that the PEC chain is as strong as possible.
|
|
| 10. |
- Forslund, Kerstin
(författare)
-
Det akuta larmsamtalet
- 2008
-
Ingår i: Telefonrådgivning inom hälso- och sjukvård. - Lund : Studentlitteratur. - 9789144047768 ; , s. 147-161
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
