Interacciones de microorganismos promotores del crecimiento vegetal y su uso potencial en formulaciones para el cultivo de papa.

Peer Revie

Cytokeratin 20-positive hepatocellular carcinoma

The differential diagnosis between hepatocellular carcinoma (HCC), cholangiocarcinoma (CC) and metastatic colorectal adenocarcinoma (MCA) may be difficult when only based on morphology. For this purpose immunohistochemical analyses are often required, utilizing antibodies directed against CK8-18, Hep-Par1, glypican 3, CK7, CK19, CK20. Here we report a case of a 65-year-old man who presented with a clinical picture of decompensated cirrhosis. Ultrasonography revealed two nodular areas in the right liver lobe. Liver needle biopsy revealed micro-macronodular cirrhosis associated with HCC with trabecular and pseudoglandular patterns. Immunohistochemically, tumour cells were diffusely positive for CK8-18 and also diffusely immunostained by glypican 3 and Hep-Par1. Interestingly, a diffuse and strong staining for CK20 was detected in the vast majority of tumor cells, particularly in the areas showing a pseudo-glandular pattern. No immunostaining for CK7 and CK19 was found in the tumor cells. The tumor behaved aggressively, with a rapid diffusion to the whole liver. The patient died from the disease few months after presentation. These findings underline that the interpretation of the expression of CK20 alone in the differential diagnosis among HCC, CC and MCA should be done with caution because a diffuse immunoreactivity for CK20 alone may not rule out the diagnosis of HCC

HLA-G expression and role in advanced-stage classical Hodgkin lymphoma

Non-classical human leucocyte antigen (HLA)-G class I molecules have an important role in tumor immune escape mechanisms. We investigated HLA-G expression in lymphonode biopsies taken from 8 controls and 20 patients with advanced-stage classical Hodgkin lymphoma (cHL), in relationship to clinical outcomes and the HLA-G 14-basepair (14-bp) deletion-insertion (del-ins) polymorphism. Lymphnode tissue sections were stained using a specific murine monoclonal HLA-G antibody. HLA-G protein expression was higher in cHL patients than controls. In the group of PET-2 positive (positron emission tomography carried out after 2 cycles of standard chemotherapy) patients with a 2-year progression-free survival rate (PFS) of 40%, we observed high HLA-G protein expression within the tumor microenvironment with low expression on Hodgkin and Reed-Sternberg (HRS) cells. Conversely, PET-2 negative patients with a PFS of 86% had higher HLA-G protein expression levels on HRS cells compared to the microenvironment. Lower expression on HRS cells was significantly associated with the HLA-G 14-bp ins/ins genotype. These preliminary data suggest that the immunohistochemical pattern of HLA-G protein expression may represent a useful tool for a tailored therapy in patients with cHL, based on the modulation of HLA-G expression in relation to achievement of negative PET-

Gardens for seniors : a case study in nursing homes in Milan (Italy)

The health-related benefits of accessing green areas (reducing stress levels, supporting physical activity, improving mood and quality of life) are particularly important for older adults, especially in long-term care settings. Well-designed outdoors environments can encourage older adults to spend more time outside. In this context, the authors conducted a research on 60 Nursing Homes in the Milan area in order to collect information on size, conditions and quality of green spaces, using the Seniors' Outdoor Survey (SOS-2), an instrument specifically designed to assess the ability of a green area to fit the needs of seniors and guarantee accessibility and usability for them. SOS-2 has 50 items grouped in 5 domains (lush garden setting, safe and comfortable, outdoor walking and activities, easy to see and reach, connect to the world). The average size of the gardens is 3160 m2with 60% of the structures in the range 1000-3000 m2. The garden area per bed has an average of 28.8 m2with over 80% of the structures with more than 9 m2of garden per bed. The SOS-2 tool uses a scale ranging from 1 (minimum) to 7 (maximum). The registered average score of the gardens is 3.29, with about 70% of gardens with an average score of less than 3.5. Despite the good supply of outdoor spaces nursing homes need a future increase in their quality. Research can contribute to growing the awareness that is necessary to adequately design the gardens in order to obtain the desired benefits

A transient homotypic interaction model for the influenza A virus NS1 protein effector domain

Influenza A virus NS1 protein is a multifunctional virulence factor consisting of an RNA binding domain (RBD), a short linker, an effector domain (ED), and a C-terminal 'tail'. Although poorly understood, NS1 multimerization may autoregulate its actions. While RBD dimerization seems functionally conserved, two possible apo ED dimers have been proposed (helix-helix and strand-strand). Here, we analyze all available RBD, ED, and full-length NS1 structures, including four novel crystal structures obtained using EDs from divergent human and avian viruses, as well as two forms of a monomeric ED mutant. The data reveal the helix-helix interface as the only strictly conserved ED homodimeric contact. Furthermore, a mutant NS1 unable to form the helix-helix dimer is compromised in its ability to bind dsRNA efficiently, implying that ED multimerization influences RBD activity. Our bioinformatical work also suggests that the helix-helix interface is variable and transient, thereby allowing two ED monomers to twist relative to one another and possibly separate. In this regard, we found a mAb that recognizes NS1 via a residue completely buried within the ED helix-helix interface, and which may help highlight potential different conformational populations of NS1 (putatively termed 'helix-closed' and 'helix-open') in virus-infected cells. 'Helix-closed' conformations appear to enhance dsRNA binding, and 'helix-open' conformations allow otherwise inaccessible interactions with host factors. Our data support a new model of NS1 regulation in which the RBD remains dimeric throughout infection, while the ED switches between several quaternary states in order to expand its functional space. Such a concept may be applicable to other small multifunctional proteins

Transmembrane helix dynamics of bacterial chemoreceptors supports a piston model of signalling.

Transmembrane α-helices play a key role in many receptors, transmitting a signal from one side to the other of the lipid bilayer membrane. Bacterial chemoreceptors are one of the best studied such systems, with a wealth of biophysical and mutational data indicating a key role for the TM2 helix in signalling. In particular, aromatic (Trp and Tyr) and basic (Arg) residues help to lock α-helices into a membrane. Mutants in TM2 of E. coli Tar and related chemoreceptors involving these residues implicate changes in helix location and/or orientation in signalling. We have investigated the detailed structural basis of this via high throughput coarse-grained molecular dynamics (CG-MD) of Tar TM2 and its mutants in lipid bilayers. We focus on the position (shift) and orientation (tilt, rotation) of TM2 relative to the bilayer and how these are perturbed in mutants relative to the wildtype. The simulations reveal a clear correlation between small (ca. 1.5 Å) shift in position of TM2 along the bilayer normal and downstream changes in signalling activity. Weaker correlations are seen with helix tilt, and little/none between signalling and helix twist. This analysis of relatively subtle changes was only possible because the high throughput simulation method allowed us to run large (n = 100) ensembles for substantial numbers of different helix sequences, amounting to ca. 2000 simulations in total. Overall, this analysis supports a swinging-piston model of transmembrane signalling by Tar and related chemoreceptors

Molecular Modeling of Mechanosensory Ion Channel Structural and Functional Features

The DEG/ENaC (Degenerin/Epithelial Sodium Channel) protein family comprises related ion channel subunits from all metazoans, including humans. Members of this protein family play roles in several important biological processes such as transduction of mechanical stimuli, sodium re-absorption and blood pressure regulation. Several blocks of amino acid sequence are conserved in DEG/ENaC proteins, but structure/function relations in this channel class are poorly understood. Given the considerable experimental limitations associated with the crystallization of integral membrane proteins, knowledge-based modeling is often the only route towards obtaining reliable structural information. To gain insight into the structural characteristics of DEG/ENaC ion channels, we derived three-dimensional models of MEC-4 and UNC-8, based on the available crystal structures of ASIC1 (Acid Sensing Ion Channel 1). MEC-4 and UNC-8 are two DEG/ENaC family members involved in mechanosensation and proprioception respectively, in the nematode Caenorhabditis elegans. We used these models to examine the structural effects of specific mutations that alter channel function in vivo. The trimeric MEC-4 model provides insight into the mechanism by which gain-of-function mutations cause structural alterations that result in increased channel permeability, which trigger cell degeneration. Our analysis provides an introductory framework to further investigate the multimeric organization of the DEG/ENaC ion channel complex

Structure and Mode-of-Action of the Two-Peptide (Class-IIb) Bacteriocins

This review focuses on the structure and mode-of-action of the two-peptide (class-IIb) bacteriocins that consist of two different peptides whose genes are next to each other in the same operon. Optimal antibacterial activity requires the presence of both peptides in about equal amounts. The two peptides are synthesized as preforms that contain a 15–30 residue double-glycine-type N-terminal leader sequence that is cleaved off at the C-terminal side of two glycine residues by a dedicated ABC-transporter that concomitantly transfers the bacteriocin peptides across cell membranes. Two-peptide bacteriocins render the membrane of sensitive bacteria permeable to a selected group of ions, indicating that the bacteriocins form or induce the formation of pores that display specificity with respect to the transport of molecules. Based on structure–function studies, it has been proposed that the two peptides of two-peptide bacteriocins form a membrane-penetrating helix–helix structure involving helix–helix-interacting GxxxG-motifs that are present in all characterized two-peptide bacteriocins. It has also been suggested that the membrane-penetrating helix–helix structure interacts with an integrated membrane protein, thereby triggering a conformational alteration in the protein, which in turn causes membrane-leakage. This proposed mode-of-action is similar to the mode-of-action of the pediocin-like (class-IIa) bacteriocins and lactococcin A (a class-IId bacteriocin), which bind to a membrane-embedded part of the mannose phosphotransferase permease in a manner that causes membrane-leakage and cell death

Controlled growth of the self-modulation of a relativistic proton bunch in plasma

A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.info:eu-repo/semantics/publishedVersio