Daphnia and ciliates: who is the prey?

The fortuitous observation of a Daphnia infested by Gymnostomatida led us to hypothesize that egg predation by ciliates could be an important mechanism regulating cladoceran population dynamics. In light of this hypothesis we reanalysed data on the dynamics of Daphnia eggs and of one Gymnostomatida species from Lago Maggiore (1996). This communication is mainly a plea to examine data where both cladocerans and Gymnostomatida were collected, to verify if the occurrence of this yet undescribed eggvoricity is widespread. Further research is needed to investigate the ecological significance of this phenomenon

Mean Difference of Truncated Normal Distribution

The purpose of this paper is to broaden the knowledge of mean difference and, in particular, of an important distribution model known as truncated normal distribution, which is widely used in applied sciences and economics. In this work, we obtained the general formula of mean difference, which is not yet reported in literature, for the aforementioned distribution model and also for particular truncated cases

Arundo donax as an energy crop: pros and cons of the utilization of this perennial plant

Arundo donax (giant reed) is a rhizomatous grass widely found in temperate and subtropical regions. Because of its capacity to grow vigorously in marginal land, it is considered as a dangerous weed plant. However, humans contributed to the dispersion of this plant around the world because Arundo is used it for multiple purposes such as reeds in woodwind musical instruments, roof thatching and fishing rods. In recent years A. donax, due to its high biomass production has been also considered as a promising energy crop. Nevertheless, some important issues must be addressed. In fact, A. donax is a sterile plant and its propagation is based on vegetative propagation (fragmentation of rhizomes or canes) and in vitro culture, making establishing the crop on a large scale very expensive. Furthermore the geneticists cannot carry out conventional breeding programmes, so improvement will be based on ecotype selection, chemical and physical mutagenesis, and transgenesis techniques. Another aspect to consider for a massive utilization of A. donax as an energy crop consists in the scarcity of data on long-term field experiments, since the duration of the crop’s life is 12-15 years. Hence, in this short review, we will bring together the principal pros and cons of this new putative energy crop

Splenic Doppler Resistive Index Variation Mirrors Cardiac Responsiveness and Systemic Hemodynamics upon Fluid Challenge Resuscitation in Postoperative Mechanically Ventilated Patients

Objective. To test if splenic Doppler resistive index (SDRI) allows noninvasive monitoring of changes in stroke volume and regional splanchnic perfusion in response to fluid challenge. Design and Setting. Prospective observational study in cardiac intensive care unit. Patients. Fifty-three patients requiring mechanical ventilation and fluid challenge for hemodynamic optimization after cardiac surgery. Interventions. SDRI values were obtained before and after volume loading with 500 mL of normal saline over 20 min and compared with changes in systemic hemodynamics, determined invasively by pulmonary artery catheter, and arterial lactate concentration as expression of splanchnic perfusion. Changes in stroke volume >10% were considered representative of fluid responsiveness. Results. A <4% SDRI reduction excluded fluid responsiveness, with 100% sensitivity and 100% negative predictive value. A >9% SDRI reduction was a marker of fluid responsiveness with 100% specificity and 100% positive predictive value. A >4% SDRI reduction was always associated with an improvement of splanchnic perfusion mirrored by an increase in lactate clearance and a reduction in systemic vascular resistance, regardless of fluid responsiveness. Conclusions. This study shows that SDRI variations after fluid administration is an effective noninvasive tool to monitor systemic hemodynamics and splanchnic perfusion upon volume administration, irrespective of fluid responsiveness in mechanically ventilated patients after cardiac surgery

Studi limnologici sul Lago Alto Flumendosa (Sardegna centrale): stato trofico e fitoplancton

Alto Flumendosa Reservoir (Central Sardinia), was investigated from February 1990 to February 1993, to study either long time period phytoplankton variations in a mesotrophic mediterranean reservoir and to value the influence of a cage rearing pisciculture on its trophic status. The annual mean values of clorophyll a varied from 2.3 mg m-3 in 1991 to 11.1 mg m-3 in 1990, annual mean values of biomass from 0.5 mg l-1 in 1993 to 3.9 mg l-1 in 1990 and annual mean values of cellular density from 6 x 106 cells l-1 in 1993 to 11.3 x 106 cells l-1 in 1990. Despite great variations in the species composition of phytoplankton in each year, a general scheme in the algal succession was found with Cryptophyceae in the colder months, Chlorophyceae in the spring months (sometimes in autumn), Cyanophyceae and Dinophyceae in summer, Bacillariophyceae in autumn, Chrysophyceae between winter and spring and Conjugatophyceae in summer or in winter. The trophic status on the basis of phytoplankton composition, clorophyll a, annual mean values of total phosphorus (from 19 mg P m-3 in 1993 to 25 mg P m-3 1990) was mesotrophic but in 1990 the eutrophic probability, on the basis of chlorophyll a, was higher. The cage rearing pisciculture was presumed to be responsible of the strong oxygen decreases in hypolimnetic water at the end of the stratification periods

Two motors and one spring: hypothetic roles of non-muscle Myosin II and submembrane actin-based Cytoskeleton in cell volume sensing

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Changes in plasma membrane curvature and intracellular ionic strength are two key features of cell volume perturbations. In this hypothesis we present a model of the responsible molecular apparatus which is assembled of two molecular motors [non-muscle myosin II (NMMII) and protrusive actin polymerization], a spring [a complex between the plasma membrane (PM) and the submembrane actin-based cytoskeleton (smACSK) which behaves like a viscoelastic solid] and the associated signaling proteins. We hypothesize that this apparatus senses changes in both the plasma membrane curvature and the ionic strength and in turn activates signaling pathways responsible for regulatory volume increase (RVI) and regulatory volume decrease (RVD). During cell volume changes hydrostatic pressure (HP) changes drive alterations in the cell membrane curvature. HP difference has opposite directions in swelling versus shrinkage, thus allowing distinction between them. By analogy with actomyosin contractility that appears to sense stiffness of the extracellular matrix we propose that NMMII and actin polymerization can actively probe the transmembrane gradient in HP. Furthermore, NMMII and protein-protein interactions in the actin cortex are sensitive to ionic strength. Emerging data on direct binding to and regulating activities of transmembrane mechanosensors by NMMII and actin cortex provide routes for signal transduction from transmembrane mechanosensors to cell volume regulatory mechanisms.info:eu-repo/semantics/publishedVersio

Pleiotropic and potentially beneficial effects of reactive oxygen species on the intracellular signaling pathways in endothelial cells

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Endothelial cells (ECs) are exposed to molecular dioxygen and its derivative reactive oxygen species (ROS). ROS are now well established as important signaling messengers. Excessive production of ROS, however, results in oxidative stress, a significant contributor to the development of numerous diseases. Here, we analyze the experimental data and theoretical concepts concerning positive pro-survival effects of ROS on signaling pathways in endothelial cells (ECs). Our analysis of the available experimental data suggests possible positive roles of ROS in induction of pro-survival pathways, downstream of the Gi-protein-coupled receptors, which mimics insulin signaling and prevention or improvement of the endothelial dysfunction. It is, however, doubtful, whether ROS can contribute to the stabilization of the endothelial barrier.info:eu-repo/semantics/publishedVersio

Endothelial cell plasma membrane biomechanics mediates effects of pro-inflammatory factors on endothelial mechanosensors: vicious circle formation in atherogenic inflammation

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Chronic low-grade vascular inflammation and endothelial dysfunction significantly contribute to the pathogenesis of cardiovascular diseases. In endothelial cells (ECs), anti-inflammatory or pro-inflammatory signaling can be induced by different patterns of the fluid shear stress (SS) exerted by blood flow on ECs. Laminar blood flow with high magnitude is anti-inflammatory, while disturbed flow and laminar flow with low magnitude is pro-inflammatory. Endothelial mechanosensors are the key upstream signaling proteins in SS-induced pro- and anti-inflammatory responses. Being transmembrane proteins, mechanosensors, not only experience fluid SS but also become regulated by the biomechanical properties of the lipid bilayer and the cytoskeleton. We review the apparent effects of pro-inflammatory factors (hypoxia, oxidative stress, hypercholesterolemia, and cytokines) on the biomechanics of the lipid bilayer and the cytoskeleton. An analysis of the available data suggests that the formation of a vicious circle may occur, in which pro-inflammatory cytokines enhance and attenuate SS-induced pro-inflammatory and anti-inflammatory signaling, respectively.This research was funded by grant from “Fondo di Ateneo per la ricerca 2020”, University of Sassari, Italy.info:eu-repo/semantics/publishedVersio

Il Genere <i>Oscillatoria</i> nel fitoplancton del Lago Mulargia (Sardegna centro-meridionale) nell'arco di sette anni (dal 1985 al 1991)

Il genere Oscillatoria, con le specie Oscillatoria rubescens DC. ed Oscillatoria tenuis Ag., negli ultimi sette anni (dal 1985 al 1991) è stato un elemento costitutivo fondamentale e caratterizante del fitoplancton del Lago Mulargia (Sardegna centro-meridionale). Dal febbraio 1985, subito dopo un'intensa fioritura di O. rubescens, la continua osservazione del fitoplancton del lago ha permesso di rilevare la costante presenza di questa specie, affiancata dal 1989 da O. tenuis

Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections