The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle

Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis

Clinical Benefit of Early Anticoagulation in Cardioembolic Stroke

Background: Nonvalvular atrial fibrillation is the most common source of cardiac embolism with a high reported risk of stroke and a high stroke-related mortality. A common clinical dilemma in patients with acute stroke is whether the detection of one of the major cardiac sources of emboli requires an early anticoagulation to reduce early stroke recurrence and mortality. Methods: In this review, we report on the results of clinical trials that have investigated the efficacy of early treatment for acute cardioembolic stroke. Results: Large clinical trials demonstrate that there is no evidence supporting the administration of heparin in patients with acute ischemic stroke within 48 h from stroke onset. Conclusions: The results of recent studies showing an advantage of the very early administration of heparin (<3 h from stroke onset) should encourage clinicians to perform further trials on the efficacy of an early administration of heparin in acute cardioembolic stroke

Perspectives of the encapsulation technology in the nursery activity of Citrus

The genetic and phytosanitary certification has to guarantee the quality of the propagation material also in Citrus. Traditional methods can be assisted by the techniques of in vitro culture, which are fundamental for the mass production of high quality plants. The encapsulation technology represents an innovative tool to combine the advantages of micropropagation with handling ease, storability, reduced size of the propagules, mechanization potentiality, transportability of the gamic seeds. In this work somatic embryos obtained from in vitro anther culture of the cultivar Mandarino Tardivo di Ciaculli (Citrus reticulata Blanco) were encapsulated in a sodium alginate matrix and synthetic seeds were obtained. The conversion ability in non sterile conditions of the synthetic seeds has been evaluated and the addition to the artificial endosperm of the fungicide Thiophanate-methyl did not limit the further development into plantlets of the encapsulated somatic embryos sown on paper (control) and on perlite. A high level of viability has been observed and conversion in ex vitro conditions on substrates similar to those used in the traditional nursery structures (perlite and paper-filter) has been obtained

The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle

Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis

Development and Experimental Characterization of a Small Scale Solar Powered Organic Rankine Cycle (ORC)

Solar thermal power plants have been widely studied in recent years as solar energy is clean, affordable and largely available. The possibility of converting solar thermal energy into electricity with small scale (lower than 10 kWe) Organic Rankine Cycle (ORC) plants operating at low temperature (lower than 130\ub0C), seems today a viable option. In this paper, the design and development of prototypal small scale ORC plant (< 10 kWe) is presented. The ORC, equipped with a scroll expander and installed in Florence, Italy, is powered by parabolic trough solar collectors (PTC) with collector surface area of 98 m2. In the first part of the paper the experimental data collected during the lab tests are presented. Then, the data collected during the field test are presented and discussed. A gross electrical efficiency up to 8% has been achieved. The value of net efficiency is dependent on the power absorbed by the auxiliary components that have not been optimized yet

An insight into the degradation processes of the anti-hypertensive drug furosemide

Furosemide (FUR), an active pharmaceutical ingredient (API) belonging to a group of drugs known as loop diuretics, has widespread use, but, is characterized by a strong instability to light, which causes chemical transformations that could give a yellowing phenomenon and have a significant impact from a health and marketing point of view. Many studies have tried to explain this phenomenon under different experimental conditions, but no detailed explanation of the yellowing phenomenon has been provided. This work, unlike the others, provides an overall view and explanation of the behavior of FUR in relation to the yellowing phenomenon, both in the solution and in solid state, considering several aspects, such as light exposure, presence of oxygen, and moisture effects

An improved encapsulation protocol for regrowth and conservation of four ornamental species

The encapsulation technology, initially developed for clonal propagation through the production of synthetic seeds with somatic embryos, is currently proposed for use with non-embryogenic explants, such as buds and nodal segments (unipolar propagules). In the present study, the encapsulation procedure and its effect on shoot regeneration were evaluated. Apical buds isolated from shoot cultures of four ornamental species (Photinia × fraseri Dress., Polygala myrtifolia L., Metrosideros excelsa Soland. ex Gaertn., and Rosa) were encapsulated in 3% sodium alginate. Effects of complexation time, sucrose concentration, and storage temperature on the regrowth ability of propagules were assessed. With the appropriate combination of sucrose concentration and polymerization time, the encapsulated explants proved to have a better regrowth (80–100%) after sowing than the naked ones. In addition, medium-term storage of Metrosideros encapsulated explants promoted a high level of regrowth (74%) after 4 months in the dark at 10°C; while polygala beads were preserved up to 8 months regardless of storage temperatures. Potential current applications of encapsulation technology and the future use of beads in vivo conditions are also discussed

In vitro storage of synthetic seeds: Effect of different storage conditions and intervals on their conversion ability

In vitro derived shoots of olive cv. Moraiolo were employed in synthetic seeds preparation by alginate encapsulation, and then stored in artificial endosperm solution at cold (4°C) and room storage (21 ± 2°C) conditions in interaction with different storage intervals of 0, 15, 30, 45 and 60 days to evaluate the comparative regrowth and conversion capacity of synthetic seeds. Cold stored synthetic seeds were superior in terms of their regrowth capacity than that of room stored ones for all the growth parameters studied. A promising degree of interaction was observed between 4°C and 45 days of storage interval for regrowth percentage as well as for shoot and root development. Moreover, an ascending trend was recorded in conversion potential with an increase in storage intervals up to 45 days (S3) whereas there was a declining trend after that up to 60 days (S4). Moreover plantlets regenerated from synthetic seeds, with 4 - 6 fully expanded leaves and well developed root system were successfully acclimatized under ex vitro conditions. The protocol can be used for germplasm exchange of woody trees and preparation of synthetic seed.Keyword: Synthetic, seed, olive, encapsulation, storage, conversionAfrican Journal of Biotechnology Vol. 9(35), pp. 5712-5721, 30 August, 201

AKTIP/Ft1, a new shelterin-interacting factor required for telomere maintenance

Telomeres are nucleoprotein complexes that protect the ends of linear chromosomes from incomplete replication, degradation and detection as DNA breaks. Mammalian telomeres are protected by shelterin, a multiprotein complex that binds the TTAGGG telomeric repeats and recruits a series of additional factors that are essential for telomere function. Although many shelterin-associated proteins have been so far identified, the inventory of shelterin-interacting factors required for telomere maintenance is still largely incomplete. Here, we characterize AKTIP/Ft1 (humanAKTIP and mouse Ft1 are orthologous), a novel mammalian shelterin-bound factoridentified on the basis of its homology with the Drosophila telomere protein Pendolino. AKTIP/Ft1 shares homology with the E2 variant ubiquitin-conjugating (UEV) enzymes and has been previously implicated in the control of apoptosis and in vesicle trafficking. RNAi-mediated depletion of AKTIP results in formation of telomere disfunction foci (TIFs). Consistent with these results, AKTIP interacts with telomeric DNA and binds the shelterin components TRF1 and TRF2 both in vivo and in vitro. Analysis of AKTIP- depleted human primary fibroblasts showed that they are defective in PCNA recruiting and arrest in the S phase due to the activation of the intra S checkpoint. Accordingly, AKTIP physically interacts with PCNA and the RPA70 DNA replication factor. Ft1-depleted p53-/- MEFs did not arrest in the S phase but displayed significant increases in multiple telomeric signals (MTS) and sister telomere associations (STAs), two hallmarks of defective telomere replication. In addition, we found an epistatic relation for MST formation between Ft1 and TRF1, which has been previously shown to be required for replication fork progression through telomeric DNA. Ch-IP experiments further suggested that in AKTIP-depleted cells undergoing the S phase, TRF1 is less tightly bound to telomeric DNA than in controls. Thus, our results collectively suggest that AKTIP/Ft1 works in concert with TRF1 to facilitate telomeric DNA replication

Neem Oil Used as a "Complex Mixture" to Improve In Vitro Shoot Proliferation in Olive

Shoots of the olive cultivar Moraiolo were previously cultured in aseptic conditions on Olive Medium (OM), with the addition of 4 mg·L−1 of zeatin, 30 g·L−1 of sucrose, and 7 g·L−1 of agar. Then, 1-cm long uninodal explants with two leaves and two axillary buds were excised from the proliferated masses and placed on the same proliferation medium enriched with four concentrations of neem oil (0—control, 0.1, 0.5, and 1.0 mL·L−1), added before sterilization. The addition of 0.1 mL·L−1 of neem oil to the medium gave an improvement in shoot regeneration. More vigorous shoots (longer proliferated shoots) were obtained along with a higher number of nodes (multiplication rate). Overall, there was a significant increase in the total fresh and dry proliferated weights. To our knowledge, this is the first report showing a strong and beneficial effect of neem oil, used as a "complex mixture," on in vitro plant regeneration