Promoter Complexity and Tissue-Specific Expression of Stress Response Components in Mytilus galloprovincialis, a Sessile Marine Invertebrate Species

The mechanisms of stress tolerance in sessile animals, such as molluscs, can offer fundamental insights into the adaptation of organisms for a wide range of environmental challenges. One of the best studied processes at the molecular level relevant to stress tolerance is the heat shock response in the genus Mytilus. We focus on the upstream region of Mytilus galloprovincialis Hsp90 genes and their structural and functional associations, using comparative genomics and network inference. Sequence comparison of this region provides novel evidence that the transcription of Hsp90 is regulated via a dense region of transcription factor binding sites, also containing a region with similarity to the Gamera family of LINE-like repetitive sequences and a genus-specific element of unknown function. Furthermore, we infer a set of gene networks from tissue-specific expression data, and specifically extract an Hsp class-associated network, with 174 genes and 2,226 associations, exhibiting a complex pattern of expression across multiple tissue types. Our results (i) suggest that the heat shock response in the genus Mytilus is regulated by an unexpectedly complex upstream region, and (ii) provide new directions for the use of the heat shock process as a biosensor system for environmental monitoring

IMMUNE RESPONSES OF NORMAL AND ARTHRITIC RATS TO VARIOUS ANTIGENS AND MITOGENS

IN OUR TRY TO STUDY THE MECHANISM BY WHICH EXPERIMENTAL ARTHRITIS (AID: ADJUVANT INDUCED DISEASE) INDUCED TO RATS WE STUDIED SOME IMMUNOLOGICAL PARAMETERS. INTHE BEGINNING WE FOUND THAT BACTERIAL LIPOPOLYSACCHARIDE FROM E.COLI IS A POLYCLONAL ACTIVATOR (MITOGEN) OF NORMAL RAT B-LYMPHOCYTES IN VIVO AND IN VITRO. INVITRO LPS ACTIVATES B-LYMPHOCYTES, ONLY AFTER ACTIVATION OF T-LYMPHOCYTES OR MACROPHAGES OR BOTH, WHICH IN TURN SECRETS FACTOR(S) WHICH HELP B-LYMPHOCYTES TORESPOND. THE MITOGENIC RESPONSES OF NORMAL OR AID RAT SPLENOCYTES TO LPS IS SIMILAR. IN CONTRAST THE MITOGENIC RESPONSE OF AID RAT SPLENOCYTES TO CON-A, 18-24 DAYS AFTER FREUD'S COMPLETE ADJUVANT (FCA) INJECTION (FOR AID INDUCTION) IS REDUCED COMPARED TO THE RESPONSE OF NORMAL RAT SPLENOCYTES. (SHORTENED)ΜΕΣΑ ΣΤΑ ΠΛΑΙΣΙΑ ΤΗΣ ΜΕΛΕΤΗΣ ΤΟΥ ΜΗΧΑΝΙΣΜΟΥ ΕΠΑΓΩΓΗΣ ΤΗΣ ΠΕΙΡΑΜΑΤΙΚΗΣ ΑΡΘΡΙΤΙΔΑΣ ΣΤΟΥΣ ΑΡΟΥΡΑΙΟΥΣ ΠΡΟΣΔΙΟΡΙΣΤΗΚΑΝ ΔΙΑΦΟΡΕΣ ΑΝΟΣΟΒΙΟΛΟΓΙΚΕΣ ΠΑΡΑΜΕΤΡΟΙ. ΑΡΧΙΚΑ,ΒΡΕΘΗΚΕ ΟΤΙ Ο ΒΑΚΤΗΡΙΑΚΟΣ ΛΙΠΟΠΟΛΥΣΑΚΧΑΡΙΤΗΣ (LPS) ΠΟΥ ΠΡΟΕΡΧΕΤΑΙ ΑΠΟ ΤΟ Ε.COLI ΕΙΝΑΙ ΠΟΛΥΚΛΩΝΙΚΟΣ ΕΝΕΡΓΟΠΟΙΗΤΗΣ (ΜΙΤΟΓΟΝΟ) ΤΩΝ Β-ΛΕΜΦΟΚΥΤΤΑΡΩΝ ΤΩΝ ΦΥΣΙΟΛΟΓΙΚΩΝ ΑΡΟΥΡΑΙΩΝ IN VIVO, ΑΛΛΑ ΚΑΙ IN VITRO ΥΠΟ ΤΗΝ ΠΡΟΥΠΟΘΕΣΗ ΟΤΙ ΘΑ ΕΝΕΡΓΟΠΟΙΗΘΟΥΝ ΣΤΗΝ ΚΑΛΛΙΕΡΓΕΙΑ ΤΑ Τ- ΛΕΜΦΟΚΥΤΤΑΡΑ 'Η ΤΑ ΜΑΚΡΟΦΑΓΑ 'Η ΚΑΙ ΤΑ ΔΥΟ, ΓΙΑ ΝΑ ΕΚΚΡΙΝΟΥΝ ΚΑΠΟΙΟΝ 'Η ΚΑΠΟΙΟΥΣ ΠΑΡΑΓΟΝΤΕΣ ΠΟΥ ΘΑ ΒΟΗΘΗΣΟΥΝ ΤΑ Β-ΛΕΜΦΟΚΥΤΤΑΡΑ ΤΟΥ ΣΠΛΗΝΑ ΝΑ ΕΝΕΡΓΟΠΟΙΗΘΟΥΝ ΑΠΟ ΤΟΝ LPS. ΟΙ ΜΙΤΟΓΟΝΙΚΕΣ ΑΠΟΚΡΙΣΕΙΣ ΤΩΝ Β-ΛΕΜΦΟΚΥΤΤΑΡΩΝ ΤΟΥ ΣΠΛΗΝΑ ΤΩΝ ΑΡΘΡΙΤΙΚΩΝ ΑΡΟΥΡΑΙΩΝ ΣΤΟ LPS ΔΕΝ ΦΑΙΝΕΤΑΙ ΝΑ ΔΙΑΦΕΡΟΥΝ ΑΠΟ ΤΗΝ ΑΝΤΙΣΤΟΙΧΗ ΑΠΟΚΡΙΣΗ ΤΩΝ ΣΠΛΗΝΟΚΥΤΤΑΡΩΝ ΤΩΝ ΦΥΣΙΟΛΟΓΙΚΩΝ ΑΡΟΥΡΑΙΩΝ. (ΠΕΡΙΚΟΠΗ

Immunization with recombinant prion protein leads to partial protection in a murine model of TSEs through a novel mechanism.

Transmissible spongiform encephalopathies are neurodegenerative diseases, which despite fervent research remain incurable. Immunization approaches have shown great potential at providing protection, however tolerance effects hamper active immunization protocols. In this study we evaluated the antigenic potential of various forms of recombinant murine prion protein and estimated their protective efficacy in a mouse model of prion diseases. One of the forms tested provided a significant elongation of survival interval. The elongation was mediated via an acute depletion of mature follicular dendritic cells, which are associated with propagation of the prion infectious agent in the periphery and in part to the development of humoral immunity against prion protein. This unprecedented result could offer new strategies for protection against transmissible encephalopathies as well as other diseases associated with follicular dendritic cells

Recognition of PrP on the cell surface.

<p>Transgenic DT40 cells expressing PrP on their surface were stained with sera from 4 mice immunized with agPrP+FA (red, green, purple and cyan histograms) (A) or from 6 mice immunized with sPrP+DnaK+FA (red, green, purple, cyan, orange and brown histograms) (B), to evaluate recognition of PrP on the cell surface. Indigo; 6H4 staining, red negative control (secondary antibody only). Differences in the modes of the histograms between agPrP+FA and sPrP+DnaK+FA mice are statistically significant (T-test, P = 0.330).</p

sPrP is recognized with the immune sera in ELISAs.

<p>Sera from mice immunized with sPrP+FA, sPrP+DnaK+FA, PrP-DnaK+FA. agPrP+FA or FA alone were tested for their ability to recognize sPrP in ELISA in a 1∶100 (<i>v/v</i>) dilution. Each point corresponds to one individual. Line: average value; dotted line OD₄₀₅. of the positive control antibody (6H4, 0.2 µg/ml).</p

Splenic PrP^Sc accumulation.

<p>Early PrP^Sc accumulation in spleens from naive mice (lane 1), mice immunized with FA alone (lane 2), agPrP alone (3) or agPrP+FA (4), 40 (A) or 80 (B) days after challenge. Splenic samples from 3 mice per group were enriched in PrP^Sc and blotted with the polyclonal antibody SAL 1 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059143#pone.0059143-Sachsamanoglou1" target="_blank">[39]</a>. Equal amounts of total protein from three mice per group were processed.</p

Survival curves of immunized mice.

<p>Naive mice and mice immunized with sPrP+FA, agPrP+FA, PrP-DnaK+FA, sPrP+DnaK+FA or FA alone were challenged with a mouse adapted scrapie strain and sacrificed at terminal point. Mice immunized with agPrP+FA survive significantly longer than naive mice (Mantel-Cox test, P = 0.0033).</p

Sera from sPrP+DnaK mice recognize total PrPSc and sPrP in western blots.

<p>A. 2.5 mg brain equivalent from terminally ill mice were blotted with 6H4 (lanes 1, 2), serum from a mouse immunized with sPrP+DnaK (lanes 3, 4) or with the secondary antibody alone (lanes 5, 6), prior (lanes 1, 3, 5) or ensuing (lanes 2, 4, 6) PrP^Sc enrichment. B. sPrP (1 µg) was blotted with serum from a mouse immunized with sPrP+DnaK (lane 7) or the secondary antibody alone (lane 8).</p