Population cytogenetics of aphidicolin-induced fragile sites

Summary Chromosome fragile sites are inducible by aphidicolin in cultured human lymphocytes. To assess the frequency and distribution of these common fragile sites in the general population, a cytogenetic survey was performed on 126 subjects, 59 males and 67 females, whose age ranged from 1 day to 72 years. Common fragile sites, induced by aphidicolin, were widespread and showed a remarkably different sensitivity among individuals; age influenced the overall frequency of fragile sites. Moreover, both age and sex seemed to modulate the expression of specific fragile sites. In our population, the most common fragile sites were: 3p14, 16q23, Xp22, 6q26, 1p31, 4q31, 1p22, 7q22, 2q33, 3q27, 2q31, 7q32, 14q24, 10q22, 5q31, 2q37, 6p21.     

Temporal and spatial changes in a mountainous area of central Italy

Abstract. In this paper we present an application of aerial remote sensing to the analysis of spatial information in a mountainous area of central Italy by applying texture measures and landscape indices. Land cover data acquired in different time periods are used to calculate measures of landscape pattern and structure at pixel level (tone and texture variables) and patch‐level (landscape indices). Images of the patches from the 1950s, 1980s and 1990s have been derived from the tone‐texture classification of scanned black‐and‐white photographs. Multitemporal analysis of landscape indices has been performed to detect changes of landscape elements and related effects on vegetation dynamics due to the reduction of human impact.     

Reproductive conflict in social insects: male production by workers in a slave-making ant

In insect societies, workers cooperate but may also pursue their individual interests, such as laying viable male eggs. The case of obligatory slave-making ants is of particular interest because workers do not engage in maintenance activities and foraging. Therefore, worker egg laying is expected to be less detrimental for colony efficiency than in related, nonparasitic species. Furthermore, as slave-making workers usually do not perform brood care and thus might have little power in manipulating sex allocation, they might be more strongly selected to increase their direct fitness by producing their own sons than workers in nonparasitic species. In this study we investigated worker reproduction in four natural colonies of the slave-making ant Polyergus rufescens, using highly variable microsatellite markers. Our results show that workers produce up to 100% of the males. This study thus presents the first direct evidence of an almost complete takeover of male reproduction by workers in ants.     

Threatened fishes of the world: Pomatoschistus canestrinii Ninni, 1883 (Gobiidae)

Environmental Biology of Fishes -     

NADPH-generating system: Influence on microsomal mono-oxygenase stability during incubation for the liver-microsomal assay with rat and mouse S9 fractions

Activity levels of 7-ethoxycoumarin O-deethylase (ED), aminopyrine N-demethylase (APD), p-nitroanisoleO-demethylase (p-NAD) and glucose-6-phosphate dehydrogenase (G-6-PDH) were determined in incubation mixtures for the liver-microsomal assay (LMA) at time 0 and after 1 and 2 h incubation under conditions for mutagenic assay. The experiments were performed with S9 liver fractions from mice (induced with Na-phenobarbital and β-naphthoflavone) and rats (induced with Aroclor 1254) with and without G-6-PDH in the incubation mixtures.

In the absence of G-6-PDH the activities were significantly lower at time 0 in the mouse. The pattern of stability, however, was similar for the activities, with an increase of stability after 1 and 2 h of pre-incubation (an exception for p-NAD).

Only ED activity showed a similar behaviour in the rat. No differences were present for APD and p-NAD activities at time 0 in the rat, but the enzyme stabilities were significantly decreased after 2 h of incubation (about 15% and 10% for APD and p-NAD respectively) in the absence of G-6-PDH.

At time 0, the amounts of G-6-PDH differed between mouse and rat fractions; however, during the incubations for LMA they decreased by about 57% and 53% for the two species, respectively. In addition to the above biochemical results, the presence of exogenous G-6-PDH in the incubations for the mutagenic assay, significantly increased the mitotic gene conversion and mitotic crossing-over of dimethylnitrosamine (DMN) and AR2MNFN (a nitroimidazo[2,1-b]thiazole) in the D₇ strain of Saccharomyces cerevisiae.     

On-column epimerization of dihydroartemisinin: an effective analytical approach to overcome the shortcomings of the International Pharmacopoeia monograph

We developed a cryo-HPLC/UV method for the simultaneous determination of artemisinin (1), alpha-dihydroartemisinin (2alpha), beta-dihydroartemisinin (2beta), and a ubiquitous thermal decomposition product of 2 (designated as diketoaldehyde, 3), starting from the International Pharmacopoeia monograph on dihydroartemisinin. The method takes for the first time the on-column epimerization process of 2 into consideration. Chromatographic separation was obtained under reversed-phase conditions on a Symmetry C18 column (3.5 microm particle size) with a mobile phase consisting of acetonitrile-water 60:40 (v/v), delivered at 0.60-1.00 ml/min flow-rates, with ultraviolet detection at low wavelength (lambda = 210 nm). Low temperatures (T = 0-10 degrees C) were selected on the grounds of a diastereoselective dynamic HPLC (DHPLC) study performed at different temperatures, aimed at identifying the best experimental conditions capable of minimizing the on-column interconversion process.     

Risk factors and outcomes of candidemia caused by biofilm-forming isolates in a tertiary care hospital

Background

Very few data exist on risk factors for developing biofilm-forming Candida bloodstream infection (CBSI) or on variables associated with the outcome of patients treated for this infection.

Methods and Findings

We identified 207 patients with CBSI, from whom 84 biofilm-forming and 123 non biofilm-forming Candida isolates were recovered. A case-case-control study to identify risk factors and a cohort study to analyze outcomes were conducted. In addition, two sub-groups of case patients were analyzed after matching for age, sex, APACHE III score, and receipt of adequate antifungal therapy. Independent predictors of biofilm-forming CBSI were presence of central venous catheter (odds ratio [OR], 6.44; 95% confidence interval [95% CI], 3.21–12.92) or urinary catheter (OR, 2.40; 95% CI, 1.18–4.91), use of total parenteral nutrition (OR, 5.21; 95% CI, 2.59–10.48), and diabetes mellitus (OR, 4.47; 95% CI, 2.03–9.83). Hospital mortality, post-CBSI hospital length of stay (LOS) (calculated only among survivors), and costs of antifungal therapy were significantly greater among patients infected by biofilm-forming isolates than those infected by non-biofilm-forming isolates. Among biofilm-forming CBSI patients receiving adequate antifungal therapy, those treated with highly active anti-biofilm (HAAB) agents (e.g., caspofungin) had significantly shorter post-CBSI hospital LOS than those treated with non-HAAB antifungal agents (e.g., fluconazole); this difference was confirmed when this analysis was conducted only among survivors. After matching, all the outcomes were still favorable for patients with non-biofilm-forming CBSI. Furthermore, the biofilm-forming CBSI was significantly associated with a matched excess risk for hospital death of 1.77 compared to non-biofilm-forming CBSI.

Conclusions

Our data show that biofilm growth by Candida has an adverse impact on clinical and economic outcomes of CBSI. Of note, better outcomes were seen for those CBSI patients who received HAAB antifungal therapy.     

Atrial natriuretic peptide effects on intracellular pH changes and ROS production in HEPG2 cells: role of p38 MAPK and phospholipase D.

AIMS: The present study was performed to evaluate Atrial Natriuretic Peptide (ANP) effects on intracellular pH, phospholipase D and ROS production and the possible relationship among them in HepG2 cells. Cancer extracellular microenvironment is more acidic than normal tissues and the activation of NHE-1, the only system able to regulate pHi homeostasis in this condition, can represent an important event in cell proliferation and malignant transformation. METHODS: The ANP effects on pHi were evaluated by fluorescence spectrometry. The effects on p38 MAPK and ROS production were evaluated by immunoblots and analysis of DCF-DA fluorescence, respectively. RT-PCR analysis and Western blotting were used to determine the ANP effect on mRNA NHE-1 expression and protein levels. PLD-catalyzed conversion of phosphatidylcholine to phosphatydilethanol (PetOH), in the presence of ethanol, was monitored by thin layer chromatography. RESULTS: A significant pHi decrease was observed in ANP-treated HepG2 cells and this effect was paralleled by the enhancement of PLD activity and ROS production. The ANP effect on pHi was coupled to an increased p38 MAPK phosphorylation and a down-regulation of mRNA NHE-1 expression and protein levels. Moreover, the relationship between PLD and ROS production was demonstrated by calphostin-c, a potent inhibitor of PLD. At the same time, all assessed ANP-effects were mediated by NPR-C receptors. CONCLUSION: Our results indicate that ANP recruits a signal pathway associated with p38 MAPK, NHE-1 and PLD responsible for ROS production, suggesting a possible role for ANP as novel modulator of ROS generation in HepG2 cells.