An “overlooked” habitat for thermophilic bacteria: the phyllosphere

Thermophilic microbes are present everywhere around us and their only known natural biotope is far away and most usually associated with geothermal energy. To answer this paradox, we explore the hypothesis that the phyllosphere (surface of leaves), due to its exposition to the sun, could well be a thermophilic habitat for microbes and thus a source of thermophilic microbes growing around 50°C – 60°C. To support this hypothesis, we reviewed the heat sources on earth and associated microbial habitats, as well as the difficult identification of thermophilic microbes. We further present an experiment to show the presence and activity of thermophilic bacteria in the phyllosphere. Leaves were collected from eleven tree species from five locations on three continents belonging to three different biomes. On fresh leaves, 16S rDNA sequencing reveals the presence of 0.2 to 7% of clearly identified thermophilic bacteria. Moreover, after incubation at 55°C under aerobic and anaerobic conditions, 16S rDNA sequencing reveals the presence of 4 to 99% of clearly identified thermophilic bacteria. The accumulation of observations provides coherence to our hypothesis and allows the emergence of a new vision of leaves as a thermophilic biotope. We then propose a life cycle of microbes belonging to the thermophilic biotope associated with leaf surfaces.

Aplastic Anemia induced by Nivolumab before a Treatment of Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

As an Immune checkpoint blockade therapy (ICB), nivolumab has demonstrated efficacy in Acute Myeloid Leukemia (AML) and various other malignancies. Nivolumab is used as an anti-programmed cell death 1 (PD-1) agent. The toxicities are observed in more than 10% of patients, because of its ability, anti-PD-1 will upregulate the activity of T-cells. Over-activated T-cells will cause immune-related adverse events such as Aplastic Anemia (AA). Here, we present a case of an over 60-years old male patient with AML, and the possibility for him to receive an allogeneic hematopoietic stem cell transplantation (allo-HSCT). The patient was treated with nivolumab and subsequently developed AA. As an additional consideration, we will also discuss whether allo-HSCT is transplantable when AA is performed during the treatment of AML.

Environmental pollutants-dependent molecular pathways and carcinogenesis

Exposure to environmental pollutants can modulate many biological and molecular processes such as gene expression, gene repair mechanisms, hormone production and function and inflammation, resulting in adverse effects on human health including the occurrence and development of different types of cancer. Carcinogenesis is a complex and long process, taking place in multiple stages and is affected by multiple factors. Some environmental molecules are genotoxic, able to damage the DNA or to induce mutations and changes in gene expression acting as initiators of carcinogenesis. Other molecules called xenoestrogens can promote carcinogenesis by their mitogenic effects by possessing estrogenic-like activities and consequently acting as endocrine disruptors causing multiple alterations in cellular signal transduction pathways. In this review, we focus on recent research on environmental chemicals-driven molecular functions in human cancers. For this purpose, we will be discussing the case of two receptors in mediating environmental pollutants effects: the established nuclear receptor, the Aryl hydrocarbon receptor (AhR) and the emerging membrane receptor, G-protein coupled estrogen receptor 1 (GPER1).

Virtual patient simulations for cardiology education and research: A CircAdapt perspective

Nowadays cardiac simulations are becoming increasingly sophisticated. This trend, part of the maturing field of computational medicine, has provided medical students and cardiologists alike with a new tool for education and research – their very own virtual “patient”. The CircAdapt biophysical model of the human heart and circulation (www.circadapt.org) allows the creation of a virtual “patient” for the study of the cardiovascular system and circulatory haemodynamics under diverse physiological and pathophysiological conditions in real time. The interactive CircAdapt model with its modular design based on established physical and physiologial principles allows dynamic monitoring of blood flow velocities, pressures and volumes in the heart and blood vessels, and across valves and shunts. As an educational tool, the CircAdapt model enables medical students and residents in cardiology, neonatology and intensive care medicine to analyze complex situations while improving their comprehension of cardiovascular physics and (patho)physiology. Moreover, the CircAdapt model has been successfully utilized as a research tool for cardiac resynchronization therapy as well as for various cardiovascular pathologies (e.g. pulmonary arterial hypertension, LBBB). All in all the CircAdapt perspective is as follows: bridge education and research - from classroom to bedside – to foster the future of clinical practice.