Interaction of a functionalized complex of the flavonoid hesperetin with the AhR pathway and CYP1A1 expression: involvement in its protective effects against benzo[<Emphasis Type="Italic">a</Emphasis>]pyrene-induced oxidative stress in human skin

Skin cancer pathogenesis is partially associated to the oxidative stress conditions induced by environmentally carcinogens such as benzo[a]pyrene (BaP). The protective effects against BaP-induced oxidative stress of the flavonoid hesperetin as a complex with the 2-hydroxypropyl-β-cyclodextrin (HE/HP-β-CyD) have been evaluated using an ex vivo human skin model. Human healthy skin has been pre-treated with the functionalized complex HE/HP-β-CyD (0.5–50 μM) before BaP (5 μM) application simulating occupational and environmental exposure. Oxidative stress was evaluated in terms of 3-(4, 5-dimethylthiazol−2-yl)-2, 5-dipheyltetrazolium bromide reduction, protein peroxidation and reactive oxygen species (ROS) formation. Additionally, it has been investigated whether the potential protective effects of HE/HP-β-CyD may be correlated to the interaction with aryl hydrocarbon receptor (AhR) pathway. A significant protection by HE/HP-β-CyD against the BaP-induced increase in ROS and carbonyl compound production, as well as reduction in tissue viability, has been observed (p < 0.001). Results obtained showed that HE/HP-β-CyD was also able to reduce BaP-induced AhR and CYP1A1 protein expression (p < 0.001). Experimental evidences provided from this study suggest significant preventive properties of HE/HP-β-CyD in the toxicity caused by environmental carcinogens such as PAHs.     

Supratidal foraminifera as ecological indicators in anthropically modified wetlands (Lagoon of Venice, Italy)

In transitional environments, the intertidal zones represent a peculiar case characterized by halophile vegetation and by a low diversity benthic community. On these areas just a few particular foraminiferal species, a class of Protoctista secreting a shell called test, can survive for a certain time out of water. They are distributed in well-defined vertical zonations with respect to mean sea level and they correspond to analogous marsh floral zonations. In particular, the Trochammina macrescens Brady + Trochammina inflata (Montagu) association characterizes the salt marsh zone above mean high water level. The potential of these taxa as bioindicators is tested, since their presence-absence-dominance differentiates the subtidal/supratidal environments. Over the last few centuries, various engineering works generated major physical changes in the Venetian Lagoon. These changes affected the natural evolution of the intertidal morphologies, the surface of which is decreasing. In an attempt to reverse this tendency, numerous artificial salt marshes have been constructed and more are under construction. In this study, the Mazzorbo artificial salt marsh, built during the second half of 1999, is considered. On its surface, 16 samples were collected along a transect line in May 2008 to verify the ecological role of this salting within the lagoon ecosystem. The sediment grain size distribution of the salt marsh reflects the dissipative role of the tide and the effect of sediment transport due to the wave and tidal action. However, the presence of only a few Trochammina individuals shows that the foraminiferal fauna did not recognise this morphology as a salt marsh. The lack of Trochammina colonisation can be related to the excessive elevation of the salt marsh surface. This hypothesis is confirmed by the lack of the salt-tolerant plant Spartina. The unsuccessful colonisation by the foraminifera seems to indicate that this artificial salting does not have the natural dynamism of the intertidal morphologies and it may only be classified as land recovery. The supratidal foraminiferal taxa can act as an ecological indicator: through their observation it is possible to verify whether an artificial salt marsh accomplishes its task of functioning as an ecological unit with the community of organisms.     

Cotrimoxazole enhances the in vitro susceptibility of Coccidioides posadasii to antifungals

The aim of the present study was to evaluate the effect of cotrimoxazole on the in vitro susceptibility of Coccidioides posadasii strains to antifungals. A total of 18 strains of C. posadasii isolated in Brazil were evaluated in this study. The assays were performed in accordance with the Clinical and Laboratory Standards Institute guidelines and the combinations were tested using the checkerboard method. The minimum inhibitory concentrations were reduced by 11, 2.4, 4.3 and 3.5 times for amphotericin B, itraconazole, fluconazole and voriconazole, respectively. Moreover, it was seen that cotrimoxazole itself inhibited C. posadasii strains in vitro. The impairment of folic acid synthesis may be a potential antifungal target for C. posadasii.     

Typing of Mycobacterium tuberculosis strains isolated in Community Health Centers of Rio de Janeiro City, Brazil

Fingerprinting of Mycobacterium tuberculosis strains from tuberculosis (TB) patients attended in Community Health Centers (CHCs) of Rio de Janeiro was performed to verify possible risk factors for TB transmission. A prospective community-based study was performed during the period of July 1996 to December 1996 by collecting sputum samples of 489 patients in 11 different CHCs in four different planning areas (APs) of the city. Bacteriological, clinical, and epidemiological information was collected and M. tuberculosis genotypes defined after restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element (DRE) fingerprinting of RFLP-clustered cases. Risk factors for TB transmission were looked for using three levels of cluster stringency. Among 349 (71%) positive cultures obtained, IS6110-RFLP typing could be performed on strains from 153 different patients. When using identity of RFLP patterns as cluster definition, 49 (32%) of the strains belonged to a cluster and none of the clinical or epidemiologic characteristics was associated with higher clustering levels. However, higher clustering level was observed in the AP including the central region of the city when compared to others. This strongly suggests that more recent transmission occurs in that area and this may be related with higher incidence of TB and HIV in this region.     

Depositional environment and biofacies characterisation of the Triassic (Carnian to Rhaetian) carbonate succession of Punta Bassano (Marettimo Island,Sicily)

The aims of this study are to reconstruct the geological setting of the Punta Bassano series (Marettimo Island, Egadi Archipelago, western Sicily) and its palaeogeographic evolution. The reference section for the Upper Triassic of Marettimo shows an alternation of marl and limestone beds together with brecciated levels. The limestones are both homogeneous mudstones with evaporite pseudomorphs and laminated with fenestrae. Foraminiferal, palynomorph, and ostracod associations constrain the Punta Bassano sequence to the Carnian-Rhaetian interval. The Punta Bassano succession represents a shallow inner ramp, ranging from open-marine environment with good water circulation to lagoonal and peritidal protected environments. Freshwater input from rivers or groundwater on the carbonate ramp is indicated by the ostracod microfauna. The comparison of facies and microfauna with those from other sequences of the Mediterranean Upper Triassic (Pyrenees, Corsica, Sardinia, and Tunisia) allows us to confine the Punta Bassano sedimentation to the northern margin of the Tethys, between the Corsican and the Pyrenean depositional setting. These new results indicate that Marettimo Island, which is considered a single structural element being formed by four tectonic units, is a piece of the southern margin of the European Plate, displaced over a longer distance to become part of the other Egadi Islands, when the Corso-Sarde block made its rotation and successive collision with the North African Margin.     

A comparative infrared spectroscopic study of glycoside hydrolases from extremophilic archaea revealed different molecular mechanisms of adaptation to high temperatures

The identification of the determinants of protein thermal stabilization is often pursued by comparing enzymes from hyperthermophiles with their mesophilic counterparts while direct structural comparisons among proteins and enzymes from hyperthermophiles are rather uncommon. Here, oligomeric beta-glycosidases from the hyperthermophilic archaea Sulfolobus solfataricus (Ss beta-gly), Thermosphaera aggregans (Ta beta-gly), and Pyrococcus furiosus (Pf beta-gly), have been compared. Studies of FTIR spectroscopy and kinetics of thermal inactivation showed that the three enzymes had similar secondary structure composition, but Ss beta-gly and Ta beta-gly (temperatures of melting 98.1 and 98.4 degrees C, respectively) were less stable than Pf beta-gly, which maintained its secondary structure even at 99.5 degrees C. The thermal denaturation of Pf beta-gly, followed in the presence of SDS, suggested that this enzyme is stabilized by hydrophobic interactions. A detailed inspection of the 3D-structures of these enzymes supported the experimental results: Ss beta-gly and Ta beta-gly are stabilized by a combination of ion-pairs networks and intrasubunit S-S bridges while the increased stability of Pf beta-gly resides in a more compact protein core. The different strategies of protein stabilization give experimental support to recent theories on thermophilic adaptation and suggest that different stabilization strategies could have been adopted among archaea.     

Detection and typing of BKV,JCV, and SV40 by multiplex nested polymerase chain reaction

A multiplex nested polymerase chain reaction (PCR) method was developed for detecting and differentiating simultaneously the DNA of polyomaviruses JC, BK, and SV40 in a single tube. In the first amplification step the same set of primers was used to amplify a conserved DNA region of the large T antigen gene of JCV, BKV, and SV40. The second round was carried out using a set of primers designed to obtain products of different size for each related virus. Subsequently, the sensitivity of the multiplex nested PCR was maximized by optimizing parameters such as primer, magnesium, and dNTP concentrations. The sensitivity of the method ranged between 1 and 10 copies of the polyomavirus genome. The assay was then used for detecting polyomavirus DNA in urine, serum, and biopsy specimens from renal transplant recipients. Based on the results obtained, the multiplex nested PCR developed in our study represents a useful tool for supporting the diagnosis of polyomavirus infection and could be used for epidemiological purposes and to better define the role of polyomaviruses in human pathology.