STUDIES ON MYXOZOAN PARASITES OF FRESHWATER FISH AND INVERTEBRATE HOSTS

A study of myxozoan parasites has been investigated in hosts from freshwater environments in the UK. Over 17,000 oligochaetes, almost 5,000 juvenile cyprinids representing 7 species and over 60 invertebrate species have been examined for the presence of myxozoan parasites. In addition, studies on the lifecycle of Tetracapsuloides bryosalmonae (the causative agent of salmonid proliferative kidney disease, PKD) and of selected cyprinid myxozoans were conducted. A total of 21 actinospore types in seven collective groups were isolated and described from oligochaetes collected from seven different river systems in England and Wales. Twelve of the actinospores isolated appear to be new to science. Differences were noted in types of actinospores released at different sites and between seasons. Most actinospores were released from oligochaetes in spring and summer with prevalence of release ranging from 0.11% up to 5.83%. The most common actinospores were members of the collective group Echinactinomyxon with seven types identified, followed by the collective group Triactinomyxon, of which 6 types were identified. Five actinospores types were each encountered only once during the study. In juvenile cyprinid fish, 14 identifiable species of myxozoans in the genera Myxidium, Myxobolus and Sphaerospora plus three developmental stages were detected by histological examination. The most common myxozoans in cyprinids were Myxobolus pseudodispar and Myxobolus pfeifferi. Roach contained the most number of myxozoan species. Only seven myxozoan species were found in chub, but pathological responses and intensity of infections, particularly with M. pseudodispar, M. pfeifferi and Myxobolus buckei were greater when compared to other cyprinids examined. Juvenile cyprinids only appear to mount a pathological response to myxozoans once sporogony is initiated and some of those responses were considered severe enough to be detrimental to host survival. Mathematical models were produced using parasite data and incorporating a variety of data, including fish length, year class strength and environmental data to attempt to demonstrate a population level effect of disease. Many of the models developed clearly show that parasitism by Myxobolus spp. and Bucephalus polymorphus in juvenile fish is strongly correlated with population success in selected UK rivers. Laboratory experiments to transmit Myxobolus spp., Myxidium spp. and Sphaerospora spp. from selected cyprinid hosts to oligochaetes were unsuccessful. The most likely explanation is that the genetic strain of Tubifex tubifex used in the trials was not susceptible to infections by the myxospores selected. Specific DNA primers for Tetracapsuloides bryosalmonae were used on samples of over 60 invertebrate species collected from sites enzootic for PKD and on all 21 actinospore types isolated during the current study. All PCR reactions were negative for the presence of T. bryosalmonae DNA. Naive rainbow trout exposed to T. bryosalmonae spores from naturally infected bryozoans by bath challenge for 10 minutes developed PKD. Intraperitoneal injection of spores failed to induce the disease. The favoured route of entry by the parasite appears to be through mucous cells in the skin epithelium.The Centre for Environment, Fisheries and Aquaculture Science, Weymouth, Dorse

Factors influencing mental health outcomes of looked after and accommodated children

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Immunostaining of spores and plasmodia of disparate myxozoan genera with comments on the properties of the sporular mucus envelope

Species of the phylum Myxozoa are common parasites of fish and can cause severe losses in cultured species. Although a number of myxozoan life-cycles have now been elucidated, little is known about the biology of these organisms in the fish host. Monoclonal antibody B4 raised to the myxozoan Tetracapsuloides bryosalmonae has been previously noted to react with a number of species infecting fish kidney. We present the results of a survey of 55 myxosporean species that determined that this antibody detects an antigen on the spore surface of 33 of these species in the genera Myxobolus, Sphaerospora and Thelohanellus. However, there appears to be no clear relationship between those spores that contain the MAb B4 reactive antigen and the host or organ in which they are detected. The antigen appears to be synthesized in the plasmodial cytoplasm and is intimately associated with the surface of the spore capsules and, where present, the mucus envelope. The nature of this envelope is further discussed in relation to its formation and distinctive properties

The phosphorylation and nuclear localization of the co-chaperone murine stress-inducible protein 1

The co-chaperone murine stress-inducible protein 1 (mSTI1), a heat shock protein 70 (Hsp70)/ heat shock protein 90 (Hsp90) organizing protein (Hop) homologue, mediates the assembly of the Hsp70/Hsp90 chaperone heterocomplex. mSTI1 is phosphorylated in vitro by cell cycle kinases, proximal to a putative nuclear localization signal (NLS), substantiating a predicted CKII-cdc2-NLS (CcN) motif at position 189-239. Stable transfectants of NIH 3T3 fibroblasts that expressed mSTI1-EGFP, NLSmSTI1-EGFP and EGFP, were prepared. Fluorescence microscopy revealed mSTI1 was cytoplasmically localized, and that this localization was not affected by the fusion of mSTI1 with the EGFP moiety. NLSmSTI1-EGFP was targeted to the nucleus compared to EGFP, suggesting that the NLSmSTI1 was a functional NLS. The localization of mSTI1 was determined under normal and heat shock conditions, inhibition of nuclear export (leptomycin B), inhibition of CKII 5,6-dichlorobenzimidazole riboside, DRB), inhibition of cdc2 kinase (olomoucine), and G1/S phase arrest (hydroxyurea). mSTI1-EGFP and mSTI1 were excluded from the nucleus in the majority of resting cells, but accumulated in the nucleus following leptomycin B treatment, implying that mSTI1 possibly undergoes a functional import process, and export via the chromosomal region maintenance 1 (CRM-1)-mediated export pathway. Hydroxyurea and olomoucine (but not DRB or heat shock) treatment increased the proportion of cells in which mSTI1-EGFP exhibited cytoplasmic and nuclear localization. 2D gel electrophoresis detected three endogenous mSTI1 isoforms, which changed following hydroxyurea treatment. Furthermore, point inactivation and mimicking of phosphorylatable residues in mSTI1 altered the translocation of the protein and the isoform composition. Modification of mSTI1 at S189 and T198 decreased the number of isoforms of mSTI1-EGFP, suggesting that the protein is modified at these sites in vivo. The removal of the in vitro cdc2 kinase site at T198 promoted a nuclear localization during G1/S phase arrest. Therefore active cdc2 kinase, but not CKII, may be required for cytoplasmic localization of mSTI1. The CKII site appears to have no regulatory role under heat shock conditions or during the cell cycle. In vitro phosphorylation studies on untagged mSTI1 further supported the prediction that S189 is the only site recognised by CKII. The cdc2 kinase site at T198, however, although the major site, was not the only site phosphorylated in vitro. However, mSTI1 and cdc2 kinase did not interact in a detectable stable complex. Bioinformatic analysis of mSTI1 revealed NLS residues were conserved in STI1 proteins, and the NLS and TPR2A motifs were in close proximity. This may have mechanistic implications for the formation of the Hsp90-mSTI1 heterocomplex. The cytoplasmic or nuclear localization of mSTI1 is predicted to be the result of a dynamic equilibrium between nuclear import and nuclear export, the fulcrum of which may be shifted under different cell cycle conditions. These data provide the first evidence of regulated nuclear import/export of a major Hsp70/Hsp90 co-chaperone, and the regulation of this nuclear import by cell cycle status and cell cycle kinases

Does professional identity impact on the credibility of leaders of integrated health and social care services?

The last two decades has seen a range of government reforms that have involved major changes in the provision of health and social care. The drive towards integration continues with the recent publication of The Health Care Bill (2021). This research has been conducted in an integrated children and young people service but is relevant to any integrated health and social care public sector service model. The services in this research are provided through area based multi-professional teams consisting of Health, Social Care and Learning and Development professionals. When the service was initially established all Service and Team Leaders had to have a registered professional qualification. This research explores through a mixed methods approach whether professional identity influences the credibility of leaders working in integrated services. Using a Mixed Methods Convergent design, data was collected and analysed from a stratified sample of (n=116) questionnaires and (n=25) semi-structured interviews, generating themes that informed the findings. The research found that Leaders managing multi-agency services do not have to be professionally qualified to gain credibility, it is a leader’s qualities and behaviours that gain them credibility when leading multi-professional teams in an integrated service. This research will assist and inform recruitment and selection processes of future service and team leaders working in integrated services. Several recommendations for future practice emerged from the research. These include the recommendation that if a non-professionally qualified service or team leader is appointed, arrangements must be in place to give presence to the professional voice at an operational, strategic and executive level. A further recommendation is to ensure that multi-professional staff receive continual training and development, to enable them to understand the different leadership qualities brought by non-professional and professional leaders so as to improve a leader’s self-belief and credibility