Synergism of Toll-like receptor-induced interleukin-12p70 secretion by monocyte-derived dendritic cells is mediated through p38 MAPK and lowers the threshold of T-helper cell type 1 responses

Toll-like receptors (TLRs) recognise specific molecular signatures of pathogens and trigger antimicrobial defence responses. Thereby, two independent signalling pathways can be distinguished: The inflammatory signalling pathway acting via the adapter molecule MyD88, leading to the activation of nuclear factor-κB (NF-κB) and mitogen activated protein kinases (MAPK) such as SAPK/JNK and p38 MAPK and the interferon (IFN) dependent pathway that signals via TRIF and results in the production of IFN-α/β. Several evolutionarily conserved molecular patterns are expressed by pathogens, leading to the question if concerted targeting of different TLRs may induce exaggerated immune responses by signalling via both TLR pathways. Here we report that monocyte-derived dendritic cells (MoDCs) combine and integrate signals received via the IFN-dependent pathway by engagement of TLR3 (poly I:C) and activation of TRIF with the MyD88-dependent pathway by ligation of TLR2 (PGN), TLR2/TLR6 (zymosan) and TLR5 (flagellin). The generally low IL-12p70 inducers resulted in combination of both pathways in cytokine levels similar to LPS, which acts via TLR4 and induces recruitment of MyD88/Tirap and TRIF/TRAM adapter proteins. The combination of TLR3 (poly I:C) or TLR4 (LPS) engagement with TLR8 (R848) ligation induced synergistic effects on cytokine production with a boost especially in IL-12p70 secretion. SB203580, a specific p38 MAPK inhibitor, completely blocked TLR ligand mediated IL-12p70 secretion, whereby specific inhibitors for SAPK/JNK (SP600125) and NF-κB (PDTC) only repressed partially the IL-12p70 secretion. Enhanced phosphorylation in poly I:C and R848 activated MoDCs revealed the critical contribution of p38 MAPK in synergistically induced IL-12p70 induction. Further investigation of primary and recall CD8⁺ T cell responses to the MUC_12-20 M1.2 peptide LLLLTVLTV and the influenza A virus matrix_58-66 peptide GILGFVFTL proved that synergistically activated MoDCs were superior compared with LPS or R848 alone. The results indicate that dendritic cells process, combine and integrate signals delivered by pathogens to launch effective adaptive immune responses.     

Expression of putative effectors of different Xylella fastidiosa strains triggers cell death-like responses in various Nicotiana model plants

The wide host range of Xylella fastidiosa (Xf) indicates the existence of yet uncharacterized virulence mechanisms that help pathogens to overcome host defences. Various bioinformatics tools combined with prediction of the functions of putative virulence proteins are valuable approaches to study microbial pathogenicity. We collected a number of putative effectors from three Xf strains belonging to different subspecies: Temecula-1 (subsp. fastidiosa), CoDiRO (subsp. pauca), and Ann-1 (subsp. sandyi). We designed an in planta Agrobacterium-based expression system that drives the expressed proteins to the cell apoplast, in order to investigate their ability to activate defence in Nicotiana model plants. Multiple Xf proteins differentially elicited cell death-like phenotypes in different Nicotiana species. These proteins are members of different enzymatic groups: (a) hydrolases/hydrolase inhibitors, (b) serine proteases, and (c) metal transferases. We also classified the Xf proteins according to their sequential and structural similarities via the I-TASSER online tool. Interestingly, we identified similar proteins that were able to differentially elicit cell death in different cultivars of the same species. Our findings provide a basis for further studies on the mechanisms that underlie both defence activation in Xf resistant hosts and pathogen adaptation in susceptible hosts.     

Matched filters, mate choice and the evolution of sexually selected traits

Background

Fundamental for understanding the evolution of communication systems is both the variation in a signal and how this affects the behavior of receivers, as well as variation in preference functions of receivers, and how this affects the variability of the signal. However, individual differences in female preference functions and their proximate causation have rarely been studied.

Methodology/Principal Findings

Calling songs of male field crickets represent secondary sexual characters and are subject to sexual selection by female choice. Following predictions from the “matched filter hypothesis” we studied the tuning of an identified interneuron in a field cricket, known for its function in phonotaxis, and correlated this with the preference of the same females in two-choice trials. Females vary in their neuronal frequency tuning, which strongly predicts the preference in a choice situation between two songs differing in carrier frequency. A second “matched filter” exists in directional hearing, where reliable cues for sound localization occur only in a narrow frequency range. There is a strong correlation between the directional tuning and the behavioural preference in no-choice tests. This second “matched filter” also varies widely in females, and surprisingly, differs on average by 400 Hz from the neuronal frequency tuning.

Conclusions/Significance

Our findings on the mismatch of the two “matched filters” would suggest that the difference in these two filters appears to be caused by their evolutionary history, and the different trade-offs which exist between sound emission, transmission and detection, as well as directional hearing under specific ecological settings. The mismatched filter situation may ultimately explain the maintenance of considerable variation in the carrier frequency of the male signal despite stabilizing selection.     

Novel Biodegradable Polyester Poly(Propylene Succinate): Synthesis and Application in the Preparation of Solid Dispersions and Nanoparticles of a Water-Soluble Drug

Poly(propylene succinate) (PPSu) polymers of average molecular weights from 2,800 to 13,100 g/mol were synthesized and characterized with regard to crystallinity, thermal properties, and cytocompatibility. Higher molecular weight samples exhibited lower degree of crystallinity and melted at lower temperatures. Melting of the polymer appeared to begin at 38°C. PPSu cytocompatibility was investigated based on human umbilical vein endothelial cells viability in the presence of increasing concentrations of polymer, and it was found that PPSu exhibited comparable cytocompatibility with poly(dl-lactide). The feasibility of applying PPSu as a drug carrier was shown for the first time, as solid dispersions and nanoparticles of sodium fluvastatin based in PPSu were prepared. Drug release rates decreased with increasing the molecular weight of PPSu in both solid dispersions and nanoparticles. For dispersions prepared from PPSu of the same molecular weight, drug release rates increased with drug loading. It appears that PPSu applicability as a drug carrier warrants further consideration.     

Ventricular ectopy from the non-coronary cusp: Pathophysiological and anatomical considerations

Non-coronary cusp (NCC) is a rare site for ventricular arrhythmias because it does not come into direct contact with the ventricular myocardium. Instead, the NCC comes in contact with the membranous septum near the His region. We describe a case of a young man with a ventricular ectopy who was successfully ablated in the NCC. In our case the much greater prematurity in the NCC than in the His region suggests that the arrhythmic site of origin is not in the peri-His area but most likely a myocardial extension adjoining the aortic root.     

Further data on the reproduction and larval development of Knipowitschia caucasica (Gobiidae)

The courting spawning and parental care behaviours of Knipowitschia caucasica (Kawrajsky) in an aquarium are described and the earliest stages of ontogenetic development are illustrated.     

Effect of triarimol on cholesterol biosynthesis in rat-liver subcellular fractions

Cholesterol biosynthesis was studied in rat-liver subcellular fractions incubated with DL-[2-¹⁴C]mevalonic acid in the presence and absence of triarimol (α-(2,4-dichlorophenyl)-α-phenyl-5-pyrimidine methanol). Triarimol strongly inhibits incorporation of radioactivity into cholesterol and this results in a large accumulation of radioactive lanosterol and 24,25-dihydro-lanosterol. The inhibition of lanosterol 14α-demethylase by triarimol was confirmed by assay of the enzyme in rat-liver microsomal fraction in the presence and absence of the inhibitor. Apart from a slight inhibition of Δ⁷-sterol-Δ⁵-dehydrogenase, triarimol did not affect the activity of any other enzyme involved in cholesterol biosynthesis from acetate.