Temporal clustering of extreme climate events drives a regime shift in rocky intertidal biofilms

Research on regime shifts has focused primarily on how changes in the intensity and duration of press disturbances precipitate natural systems into undesirable, alternative states. By contrast, the role of recurrent pulse perturbations, such as extreme climatic events, has been largely neglected, hindering our understanding of how historical processes regulate the onset of a regime shift. We performed field manipulations to evaluate whether combinations of extreme events of temperature and sediment deposition that differed in their degree of temporal clustering generated alternative states in rocky intertidal epilithic microphytobenthos (biofilms) on rocky shores. The likelihood of biofilms to shift from a vegetated to a bare state depended on the degree of temporal clustering of events, with biofilm biomass showing both states under a regime of non-clustered (60 d apart) perturbations while collapsing in the clustered (15 d apart) scenario. Our results indicate that time since the last perturbation can be an important predictor of collapse in systems exhibiting alternative states and that consideration of historical effects in studies of regime shifts may largely improve our understanding of ecosystem dynamics under climate change

Experimental evidence of spatial signatures of approaching regime shifts in macroalgal canopies

Developing early warning signals to predict regime shifts in ecosystems is a central issue in current ecological research. While there are many studies addressing temporal early warning indicators, research into spatial indicators is far behind, with field experiments even more rare. Here, we tested the performance of spatial early warning signals in an intertidal macroalgal system, where removal of algal canopies pushed the system toward a tipping point (corresponding to approximately 75% of canopy loss), marking the transition between a canopy- to a turf-dominated state. We performed a two-year experiment where spatial early warning indicators were assessed in transects where the canopy was differentially removed (from 0 to 100%). Unlike Moran correlation coefficient at lag-1, spatial variance, skewness, and spatial spectra at low frequency increased along the gradient of canopy degradation and dropped, or did not show any further increase beyond the transition point from a canopy- to a turf-dominated state (100% canopy removal). Our study provides direct evidence of the suitability of spatial early warning signals to anticipate regime shifts in natural ecosystems, emphasizing the importance of field experiments as a powerful tool to establish causal relationships between environmental stressors and early warning indicators

Ketogenic Diet in the Treatment of Gliomas and Glioblastomas

In recent years, scientific interest in the use of the ketogenic diet (KD) as a complementary approach to the standard cancer therapy has grown, in particular against those of the central nervous system (CNS). In metabolic terms, there are the following differences between healthy and neoplastic cells: neoplastic cells divert their metabolism to anaerobic glycolysis (Warburg effect), they alter the normal mitochondrial functioning, and they use mainly certain amino acids for their own metabolic needs, to gain an advantage over healthy cells and to lead to a pro-oncogenetic effect. Several works in literature speculate which are the molecular targets of KD used against cancer. The following different mechanisms of action will be explored in this review: metabolic, inflammatory, oncogenic and oncosuppressive, ROS, and epigenetic modulation. Preclinical and clinical studies on the use of KD in CNS tumors have also increased in recent years. An interesting hypothesis emerged from the studies about the possible use of a ketogenic diet as a combination therapy along with chemotherapy (CT) and radiotherapy (RT) for the treatment of cancer. Currently, however, clinical data are still very limited but encouraging, so we need further studies to definitively validate or disprove the role of KD in fighting against cancer

Solar photodegradation of irinotecan in water: optimization and robustness studies by experimental design

Irinotecan, a widely prescribed anticancer drug, is an emerging contaminant of concern that has been detected in various aquatic environments due to ineffective removal by traditional wastewater treatment systems. Solar photodegradation is a viable approach that can effectively eradicate the drug from aqueous systems. In this study, we used the design of experiment (DOE) approach to explore the robustness of irinotecan photodegradation under simulated solar irradiation. A full factorial design, including a star design, was applied to study the effects of three parameters: initial concentration of irinotecan (1.0-9.0 mg/L), pH (5.0-9.0), and irradiance (450-750 W/m(2)). A high-performance liquid chromatography coupled with a high-resolution mass spectrometry (HPLC-HRMS) system was used to determine irinotecan and identify transformation products. The photodegradation of irinotecan followed a pseudo-first order kinetics. In the best-fitted linear model determined by the stepwise model fitting approach, pH was found to have about 100-fold greater effect than either irinotecan concentration or solar irradiance. Under optimal conditions (irradiance of 750 W/m(2), 1.0 mg/L irinotecan concentration, and pH 9.0), more than 98% of irinotecan was degraded in 60 min. With respect to irradiance and irinotecan concentration, the degradation process was robust in the studied range, implying that it may be effectively applied in locations and/or seasons with solar irradiance as low as 450 W/m(2). However, pH needs to be strictly controlled and kept between 7.0 and 9.0 to maintain the degradation process robust. Considerations about the behavior of degradation products were also drawn

Spatio-temporal variability in Mediterranean rocky shore microphytobenthos

Knowledge of spatio-temporal variability of assemblages is the first step in identifying key factors affecting the abundance and distribution of organisms. Despite a long history of ecological studies on rocky intertidal habitats, there is still a lack of basic knowledge about the microphytobenthic components. We investigated the spatio-temporal variability of microphytobenthos in the northwest Mediterranean at multiple scales, including both seasonal and daily observations, as well as its composition. Spatial variability of microphytobenthic biomass varied significantly with season, with an increase in small-scale variance from cold to warm periods. Furthermore, during warmer months, small-scale variances (tens to hundreds of centimeters) were larger than large-scale components (tens to thousands of meters). These results suggest large spatiotemporal variation in the processes driving variation in microphytobenthic assemblages, including interactive effects among stressful abiotic conditions, substratum topography and grazing. In addition, observed variability on a daily scale suggested that microphytobenthos at the study site (dominated by cyanobacteria) might cope with stressful environmental conditions through both physiological and behavioral strategies at micro-spatial scales, including small movements within the substratum. Additional research on ecological and physiological aspects of rocky shore microphytobenthos is needed to better understand its role within interaction webs and primary productivity processes

Drug resistance in B and non-B subtypes amongst subjects recently diagnosed as primary/recent or chronic HIV-infected over the period 2013–2016: Impact on susceptibility to first-line strategies including integrase strand-transfer inhibitors

Objectives To characterize the prevalence of transmitted drug resistance mutations (TDRMs) by plasma analysis of 750 patients at the time of HIV diagnosis from January 1, 2013 to November 16, 2016 in the Veneto region (Italy), where all drugs included in the recommended first line therapies were prescribed, included integrase strand transfer inhibitors (InNSTI). Methods TDRMs were defined according to the Stanford HIV database algorithm. Results Subtype B was the most prevalent HIV clade (67.3%). A total of 92 patients (12.3%) were expected to be resistant to one drug at least, most with a single class mutation (60/68–88.2% in subtype B infected subjectsand 23/24–95.8% in non-B subjects) and affecting mainly NNRTIs. No significant differences were observed between the prevalence rates of TDRMs involving one or more drugs, except for the presence of E138A quite only in patients with B subtype and other NNRTI in subjects with non-B infection. The diagnosis of primary/recent infection was made in 73 patients (9.7%): they had almost only TDRMs involving a single class. Resistance to InSTI was studied in 484 subjects (53 with primary-recent infection), one patient had 143C in 2016, a total of thirteen 157Q mutations were detected (only one in primary/recent infection). Conclusions Only one major InSTI-TDRM was identified but monitoring of TDRMs should continue in the light of continuing presence of NNRTI-related mutation amongst newly diagnosed subjects, sometime impacting also to modern NNRTI drugs recommended in first-line therapy