DNA Sequence Determinants Controlling Affinity, Stability and Shape of DNA Complexes Bound by the Nucleoid Protein Fis.

The abundant Fis nucleoid protein selectively binds poorly related DNA sequences with high affinities to regulate diverse DNA reactions. Fis binds DNA primarily through DNA backbone contacts and selects target sites by reading conformational properties of DNA sequences, most prominently intrinsic minor groove widths. High-affinity binding requires Fis-stabilized DNA conformational changes that vary depending on DNA sequence. In order to better understand the molecular basis for high affinity site recognition, we analyzed the effects of DNA sequence within and flanking the core Fis binding site on binding affinity and DNA structure. X-ray crystal structures of Fis-DNA complexes containing variable sequences in the noncontacted center of the binding site or variations within the major groove interfaces show that the DNA can adapt to the Fis dimer surface asymmetrically. We show that the presence and position of pyrimidine-purine base steps within the major groove interfaces affect both local DNA bending and minor groove compression to modulate affinities and lifetimes of Fis-DNA complexes. Sequences flanking the core binding site also modulate complex affinities, lifetimes, and the degree of local and global Fis-induced DNA bending. In particular, a G immediately upstream of the 15 bp core sequence inhibits binding and bending, and A-tracts within the flanking base pairs increase both complex lifetimes and global DNA curvatures. Taken together, our observations support a revised DNA motif specifying high-affinity Fis binding and highlight the range of conformations that Fis-bound DNA can adopt. The affinities and DNA conformations of individual Fis-DNA complexes are likely to be tailored to their context-specific biological functions

Control of DNA minor groove width and Fis protein binding by the purine 2-amino group.

The width of the DNA minor groove varies with sequence and can be a major determinant of DNA shape recognition by proteins. For example, the minor groove within the center of the Fis-DNA complex narrows to about half the mean minor groove width of canonical B-form DNA to fit onto the protein surface. G/C base pairs within this segment, which is not contacted by the Fis protein, reduce binding affinities up to 2000-fold over A/T-rich sequences. We show here through multiple X-ray structures and binding properties of Fis-DNA complexes containing base analogs that the 2-amino group on guanine is the primary molecular determinant controlling minor groove widths. Molecular dynamics simulations of free-DNA targets with canonical and modified bases further demonstrate that sequence-dependent narrowing of minor groove widths is modulated almost entirely by the presence of purine 2-amino groups. We also provide evidence that protein-mediated phosphate neutralization facilitates minor groove compression and is particularly important for binding to non-optimally shaped DNA duplexes

Uno studio inedito di Enrico Pirajno di Mandralisca sull’entomofauna delle isole Eolie.

Tra i manoscritti inediti di Enrico Pirajno, conservati presso l’Archivio Storico della FondazioneMandralisca, esiste un elenco dei “Coleotteri delle isole Eolie”, che rappresenta il primo tentativo pionieristico di un catalogo dell’entomofauna dell’arcipelago. Nel presente contributo ne viene illustrato il contenuto e brevemente discussi gli aspetti relativi al suo valore storico, documentale e scientifico

Mycobacterium tuberculosis Drives Expansion of Low-Density Neutrophils Equipped With Regulatory Activities

In human tuberculosis (TB) neutrophils represent the most commonly infected phagocyte but their role in protection and pathology is highly contradictory. Moreover, a subset of low-density neutrophils (LDNs) has been identified in TB, but their functions remain unclear. Here, we have analyzed total neutrophils and their low-density and normal-density (NDNs) subsets in patients with active TB disease, in terms of frequency, phenotype, functional features, and gene expression signature. Full-blood counts from Healthy Donors (H.D.), Latent TB infected, active TB, and cured TB patients were performed. Frequency, phenotype, burst activity, and suppressor T cell activity of the two different subsets were assessed by flow cytometry while NETosis and phagocytosis were evaluated by confocal microscopy. Expression analysis was performed by using the semi-quantitative RT-PCR array technology. Elevated numbers of total neutrophils and a high neutrophil/lymphocyte ratio distinguished patients with active TB from all the other groups. PBMCs of patients with active TB disease contained elevated percentages of LDNs compared with those of H.D., with an increased expression of CD66b, CD33, CD15, and CD16 compared to NDNs. Transcriptomic analysis of LDNs and NDNs purified from the peripheral blood of TB patients identified 12 genes differentially expressed: CCL5, CCR5, CD4, IL10, LYZ, and STAT4 were upregulated, while CXCL8, IFNAR1, NFKB1A, STAT1, TICAM1, and TNF were downregulated in LDNs, as compared to NDNs. Differently than NDNs, LDNs failed to phagocyte live Mycobacterium tuberculosis (M. tuberculosis) bacilli, to make oxidative burst and NETosis, but caused significant suppression of antigen-specific and polyclonal T cell proliferation which was partially mediated by IL-10. These insights add a little dowel of knowledge in understanding the pathogenesis of human TB

A previously unreported numph cocoon of Alphasida puncticollis on the islet of Lampione (Sicilian Channel) (Coleoptera Tenebrionidae).

In this paper we present an unusual case of cocoons produced by larvae of Tenebrionid Alphasida (Glabrasida) puncticollis (Solier, 1836), which has been observed on the islet of Lampione (Sicilian Channel). Pupal cocoons have never been recorded for species belonging to this genus, and their occurrence results rarely documented within the family Tenebrionidae. Some ecological implications are discussed

The Role of Emotional Intelligence in Health Care Professionals Burnout

The purpose of this study is to explore the relationship between Emotional Intelligence (EI) and burnout in health care professionals. More specifically, this survey has the purpose of demonstrating the role of EI as a protective factor against the risk of burnout. Health professionals (doctors, nurses, and other caregivers) composed the sample. Data, collected during professional training, provided 148 employees. Major results of this survey underline the relationship between EI and burnout. As we expected, there is a negative and significant correlation between burnout and Emotional Intelligence. Moreover, burnout varies depending on length of service: burnout increases between 5 and 10 years of experience and decreases over 10 years. Indeed, burnout is differently expressed amongst healthcare professionals: more specifically, Psycho-physical exhaustion, Detriment of the relationships and Burnout (total score) has an impact on physician (doctors) more than other investigated health professionals. These findings seem to suggest the opportunity to improve Emotional Intelligence abilities through specific training programs, useful to promote the ability to cope with stress and to enrich the relationships in the workplace

Direct-acting antivirals and visceral leishmaniasis: A case report

Background: Visceral leishmaniasis is a vector-borne parasitic disease caused by protozoa belonging to the genus Leishmania. The clinical presentation of visceral leishmaniasis strictly depends on the host immunocompetency, whereas depressive conditions of the immune system impair the capability to resolve the infection and allow reactivation from sites of latency of the parasite. Case presentation: We describe a case of visceral leishmaniasis (VL) that occurred in a patient with chronic hepatitis C treated with direct-acting antiviral drugs (DAA). The hypothesized mechanism is the alteration of protective inflammation mechanisms secondary to DAA therapy. Downregulation of type II and III IFNs, their receptors, which accompany HCV clearance achieved during treatment with sofosbuvir and ribavirin might have a negative impact on a risk for reactivation of a previous Leishmania infection. We know indeed that IFN-\u3b3 is important to enhance killing mechanisms in macrophages, which are the primary target cells of Leishmania. Conclusion: Since VL is endemic in Sicily as well as in other countries of the Mediterranean basin, physicians should be aware of the possible unmasking of cryptic Leishmania infection by DAAs

Note tassonomiche e biosistematiche su Anthemis aeolica (Asteraceae).

Sono riportati i risultati relativi alla caratterizzazione morfologica, distribuzione attuale , ecologia e correlazioni sistematiche della specie endemica Anthemis aeolic

Rickettsia typhi and Haemophagocytic Syndrome

Appropriate therapy (dexamethasone, cyclosporin, and etoposide) could save the patient in those cases in which the pathogen-direct therapy has not been sufficient by itself to control the disease