DNA structural deformations in the interaction of the controller protein C.AhdI with its operator sequence

Controller proteins such as C.AhdI regulate the expression of bacterial restriction–modification genes, and ensure that methylation of the host DNA precedes restriction by delaying transcription of the endonuclease. The operator DNA sequence to which C.AhdI binds consists of two adjacent binding sites, OL and OR. Binding of C.AhdI to OL and to OL + OR has been investigated by circular permutation DNA-bending assays and by circular dichroism (CD) spectroscopy. CD indicates considerable distortion to the DNA when bound by C.AhdI. Binding to one or two sites to form dimeric and tetrameric complexes increases the CD signal at 278 nm by 40 and 80% respectively, showing identical local distortion at both sites. In contrast, DNA-bending assays gave similar bend angles for both dimeric and tetrameric complexes (47 and 38°, respectively). The relative orientation of C.AhdI dimers in the tetrameric complex and the structural role of the conserved Py-A-T sequences found at the centre of C-protein-binding sites are discussed

DNA structural deformations in the interaction of the controller protein C.AhdI with its operator sequence

Controller proteins such as C.AhdI regulate the expression of bacterial restriction–modification genes, and ensure that methylation of the host DNA precedes restriction by delaying transcription of the endonuclease. The operator DNA sequence to which C.AhdI binds consists of two adjacent binding sites, OL and OR. Binding of C.AhdI to OL and to OL + OR has been investigated by circular permutation DNA-bending assays and by circular dichroism (CD) spectroscopy. CD indicates considerable distortion to the DNA when bound by C.AhdI. Binding to one or two sites to form dimeric and tetrameric complexes increases the CD signal at 278 nm by 40 and 80% respectively, showing identical local distortion at both sites. In contrast, DNA-bending assays gave similar bend angles for both dimeric and tetrameric complexes (47 and 38°, respectively). The relative orientation of C.AhdI dimers in the tetrameric complex and the structural role of the conserved Py-A-T sequences found at the centre of C-protein-binding sites are discussed

New records of aphid species (Hemiptera: Aphididae) in Greece

Τις τελευταίες δυο δεκαετίες έχουν δημοσιευθεί αρκετές εργασίες σχετικές με την αφιδοπανίδα της Ελλάδας. Ωστόσο, ο αριθμός των καταγεγραμμένων ειδών αφίδων είναι αρκετά μικρότερος από άλλες Ευρωπαϊκές χώρες, συμπεριλαμβανομένων αυτών στη λεκάνη της Μεσογείου. Στην παρούσα εργασία συλλέξαμε δείγματα αφίδων από διάφορους ξενιστές και περιοχές της νότιας, κεντρικής και βόρειας Ελλάδας. Συνολικά συλλέχθηκαν 128 είδη αφίδων, που ανήκουν σε 55 γένη και έξι υποοικογένειες, από 200 είδη φυτών-ξενιστών. Τα περισσότερα είδη αφίδων ανήκαν στην υποοικογένεια Aphidinae (ειδικά στις φυλές Macrosiphini και Aphidini). Δεκαοκτώ από τα συλλεχθέντα είδη είναι νέες αναφορές για την Ελλάδα. Τα αποτελέσματα της παρούσας εργασίας αυξάνουν τη γνώση μας σχετικά με την αφιδοπανίδα της Ελλάδας και δείχνουν ότι ο αριθμός των καταγεγραμμένων ειδών στην Ελλάδα μπορεί να αυξηθεί σημαντικά αν πραγματοποιηθούν επιπλέον σχετικές μελέτες. Several papers have been published on aphid fauna in Greece during the last two decades, but the number of recorded species is still low compared to other European countries, including some from the Mediterranean basin. In this context, we collected aphids from various host-plants and regions in southern, central and northern Greece characterized by diverse flora, climatic conditions and ecological habitats. In total, 128 aphid species belonging to 55 genera and six subfamilies were collected on 200 host-species. Most of the species dominated the subfamily Aphidinae (especially tribes Macrosiphini and Aphidini). Among the species collected, 18 were new records in Greece. The present work improves our knowledge regarding the aphid fauna of Greece and suggests that the number of recorded species could increase further if additional studies were undertaken

Novel strategies for assessing platelet reactivity

There are many approaches to assessing platelet reactivity and many uses for such measurements. Initially, measurements were based on the ability of platelets separated from other blood cells to aggregate together following activation with an appropriate ‘aggregating agent’. Later, measurements of platelet aggregation in blood itself were performed, and this led to a point-of-care approach to platelet function testing. Measurement of secretory activity through the appearance of the activation marker P-selectin on platelets now provides an alternative approach, which enables remote testing. Measurement of vasodilator-stimulated phosphoprotein phosphorylation is also moving toward application in situations remote from the testing laboratory. Here we provide an overview of the various approaches that are now available, assess their advantages and disadvantages, and describe some of the clinical situations in which they are being used

A Pragmatic, Scalable Approach to Correct-by-Construction Process Composition Using Classical Linear Logic Inference

The need for rigorous process composition is encountered in many situations pertaining to the development and analysis of complex systems. We discuss the use of Classical Linear Logic (CLL) for correct-by-construction resource-based process composition, with guaranteed deadlock freedom, systematic resource accounting, and concurrent execution. We introduce algorithms to automate the necessary inference steps for binary compositions of processes in parallel, conditionally, and in sequence. We combine decision procedures and heuristics to achieve intuitive and practically useful compositions in an applied setting.Comment: Post-proceedings paper presented at the 28th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2018), Frankfurt am Main, Germany, 4-6 September 2018 (arXiv:1808.03326). arXiv admin note: substantial text overlap with arXiv:1803.0261

Platelet and Neutrophil Responses to Gram Positive Pathogens in Patients with Bacteremic Infection

BACKGROUND: Many Gram-positive pathogens aggregate and activate platelets in vitro and this has been proposed to contribute to virulence. Platelets can also form complexes with neutrophils but little is however known about platelet and platelet-neutrophil responses in bacterial infection. METHODOLOGY/PRINCIPAL FINDINGS: We added isolates of Gram-positive bacteria from 38 patients with a bacteremic infection to blood drawn from the same patient. Aggregometry and flow cytometry were used to assess platelet aggregation and to quantify activation of platelets, neutrophils, and platelet-neutrophils complexes (PNCs) induced by the bacteria. Fifteen healthy persons served as controls. Most isolates of Staphylococcus aureus, beta hemolytic streptococci, and Enterococcus faecalis induced aggregation of platelets from their respective hosts, whereas pneumococci failed to do so. S. aureus isolates induced platelet aggregation more rapidly in patients than in controls, whereas platelet activation by S. aureus was lower in patients than in controls. PNCs were more abundant in baseline samples from patients than in healthy controls and most bacterial isolates induced additional PNC formation and neutrophil activation. CONCLUSION/SIGNIFICANCE: We have demonstrated for the first time that bacteria isolated from patients with Gram-positive bacteremia can induce platelet activation and aggregation, PNC formation, and neutrophil activation in the same infected host. This underlines the significance of these interactions during infection, which could be a target for future therapies in sepsis

Detection and Characterization of Wolbachia Infections in Natural Populations of Aphids: Is the Hidden Diversity Fully Unraveled?

Aphids are a serious threat to agriculture, despite being a rather small group of insects. The about 4,000 species worldwide engage in highly interesting and complex relationships with their microbial fauna. One of the key symbionts in arthropods is Wolbachia, an α-Proteobacterium implicated in many important biological processes and believed to be a potential tool for biological control. Aphids were thought not to harbour Wolbachia; however, current data suggest that its presence in aphids has been missed, probably due to the low titre of the infection and/or to the high divergence of the Wolbachia strains of aphids. The goal of the present study is to map the Wolbachia infection status of natural aphids populations, along with the characterization of the detected Wolbachia strains. Out of 425 samples from Spain, Portugal, Greece, Israel and Iran, 37 were found to be infected. Our results, based mainly on 16S rRNA gene sequencing, indicate the presence of two new Wolbachia supergroups prevailing in aphids, along with some strains belonging either to supergroup B or to supergroup A