Surviving the heat:Heterogeneity of response in Saccharomyces cerevisiae provides insight into thermal damage to the membrane

Environmental heat stress impacts on the physiology and viability of microbial cells with concomitant implications for microbial activity and diversity. Previously, it has been demonstrated that gradual heating of Saccharomyces cerevisiae induces a degree of thermal resistance, whereas a heat shock results in a high level of cell death. Here, we show that the impact of exogenous nutrients on acquisition of thermal resistance differs between strains. Using single-cell methods, we demonstrate the extent of heterogeneity of the heat-stress response within populations of yeast cells and the presence of subpopulations that are reversibly damaged by heat stress. Such cells represent potential for recovery of entire populations once stresses are removed. The results show that plasma membrane permeability and potential are key factors involved in cell survival, but thermal resistance is not related to homeoviscous adaptation of the plasma membrane. These results have implications for growth and regrowth of populations experiencing environmental heat stress and our understanding of impacts at the level of the single cell. Given the important role of microbes in biofuel production and bioremediation, a thorough understanding of the impact of stress responses of populations and individuals is highly desirable

Surviving the heat:Heterogeneity of response in Saccharomyces cerevisiae provides insight into thermal damage to the membrane

International audienceEnvironmental heat stress impacts on the physiology and viability of microbial cells with concomitant implications for microbial activity and diversity. Previously, it has been demonstrated that gradual heating of Saccharomyces cerevisiae induces a degree of thermal resistance, whereas a heat shock results in a high level of cell death. Here, we show that the impact of exogenous nutrients on acquisition of thermal resistance differs between strains.Using single‐cell methods, we demonstrate the extent of heterogeneity of the heat‐stress response within populations of yeast cells and the presence of subpopulations that are reversibly damaged by heat stress. Such cells represent potential for recovery of entire populations once stresses are removed. The results show that plasma membrane permeability and potential are key factors involved in cell survival, but thermal resistance is not related to homeoviscous adaptation of the plasma membrane. These results have implications for growth and regrowth of populations experiencing environmental heat stress and our understanding of impacts at the level of the single cell. Given the important role of microbes in biofuel production and bioremediation, a thorough understanding of the impact of stress responses of populations and individuals is highly desirable

Quadruplex DNA: sequence, topology and structure.

G-quadruplexes are higher-order DNA and RNA structures formed from G-rich sequences that are built around tetrads of hydrogen-bonded guanine bases. Potential quadruplex sequences have been identified in G-rich eukaryotic telomeres, and more recently in non-telomeric genomic DNA, e.g. in nuclease-hypersensitive promoter regions. The natural role and biological validation of these structures is starting to be explored, and there is particular interest in them as targets for therapeutic intervention. This survey focuses on the folding and structural features on quadruplexes formed from telomeric and non-telomeric DNA sequences, and examines fundamental aspects of topology and the emerging relationships with sequence. Emphasis is placed on information from the high-resolution methods of X-ray crystallography and NMR, and their scope and current limitations are discussed. Such information, together with biological insights, will be important for the discovery of drugs targeting quadruplexes from particular genes

Structural studies of DNA G-quadruplexes and ligand complexes

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Randomized, phase III study comparing osmoprotective carboxymethylcellulose with sodium hyaluronate in dry eye disease.

International audiencePURPOSE: To compare a treatment containing carboxymethylcellulose (CMC) and the osmoprotective (OsPr) compatible osmolytes erythritol, L-carnitine, and glycerin (OsPr-CMC) with a standard sodium hyaluronate (Na-HY) formulation in patients with dry eye disease. METHODS: This was a 3-month, phase III, noninferiority study. Patients were randomized 1:1 to receive OsPr-CMC (OPTIVE®) or Na-HY (VISMED®). The primary efficacy outcome was the mean change from baseline in total ocular staining at day 35, scored using the 15-point Oxford scale. Noninferiority was assessed using the adjusted means. The secondary efficacy outcome was change in ocular surface disease index (OSDI) score from baseline to day 35. Other outcomes included tear osmolarity, Schirmer-I test score, OSDI, ease of use, patient acceptability, tolerability, and safety. RESULTS: A total of 82 patients were randomized. The primary efficacy analysis was per protocol (OsPr-CMC, n=37; Na-HY, n=29). OsPr-CMC was noninferior to Na-HY in terms of adjusted mean change (SE) in ocular staining score at day 35: -2.0 (0.33) with OsPr-CMC vs -1.7 (0.37) with Na-HY. Similar improvements were seen in tear osmolarity, Schirmer-I test score, OSDI, and ocular staining for OsPr-CMC and Na-HY. More patients treated with OsPr-CMC vs Na-HY liked using their eyedrops, reported that their eyes felt comfortable, and found the treatment easy to use. Both treatments were well tolerated, with no serious treatment-related adverse events. CONCLUSIONS: Compared with Na-HY, OsPr-CMC was noninferior in terms of efficacy and safety, preferred by patients, and easier to use. Osmoprotection using OsPr-CMC therefore represents a viable option for dry eye disease management

Pediatric Oncology Palliative Care Programs in Central America: Pathways to Success

Palliative care offers children who have life-limiting and life-threatening oncologic illnesses and their families improved quality of life. In some instances, impeccable symptom control can lead to improved survival. Cultural and financial barriers to palliative care in oncology patients occur in all countries, and those located in Central America are no exception. In this article, we summarize how the programs participating in the Asociación de Hemato-Oncólogos Pediatras de Centro America (AHOPCA) have developed dedicated oncology palliative care programs. The experience in Guatemala, El Salvador, Costa Rica, Panama, Dominican Republic and Haiti is detailed, with a focus on history, the barriers that have impeded progress, and achievements. Future directions, which, of course, may be impacted by the COVID-19 pandemic, are described as well