Sonia Garrido-Chamorro

The confluence of a large variety of factors, achievements and developments has resulted in the current long-term success in graft transplants. Some of these events are reviewed, paying special attention to immunosuppressant drugs, which are one of the most relevant milestones in the prevention of organ transplant rejection. The discovery, industrial exploitation, mechanisms of action and side effects of several drugs exhibiting immunosuppressive effects (e.g., corticosteroids, nitrogen mustards, mycophenolic acid, rapamycin) are deeply detailed. Furthermore, new trends in immunosuppressant research, improvement and reformulation are also reviewed. Nevertheless, the core of the manuscript is the immunosuppressant tacrolimus, also called FK506, which has been sought after due to the commercial success of cyclosporine and other immunosuppressant compounds, but also because of the side effects of those previous compounds. Thus, in the mid-1980s tacrolimus was described as a more potent immunosuppressive molecule, with less undesirable effects. Currently, tacrolimus is a well-stablished API that is used as a clinical treatment to avoid graft rejection, but also shows interesting properties in terms of decreasing the impact of some autoimmune diseases and acting as an enhancer of nerve regeneration treatments. Thus, in the 40th anniversary of its discovery, this paper describes the current state of the art of this drug and how it is adapting to new social needs and clinical trends.

Nowadays, legal regulations and social environmental concerns are converging towards the promotion of more sustainable agriculture based on organic compounds and soil preservation. These trends are fuelling the growth of the biofertilizers, which are beneficial preparations containing microorganisms able to enhance a plant’s ability to uptake essential nutrients. Their production and commercialization encompass a multitude of critical steps deeply reviewed in this manuscript through an exhaustive overview of the key stages, such as microorganism selection, new environmental sources, upscaling to field trials, encapsulation, current application systems and regulatory considerations. However, although the economical expectations are promising, several methodological, environmental, and legal concerns are undermining their advancement. The redefinition of international legal frameworks, their enhancement based on trending technologies, and the fostering of multidisciplinary collaboration across sectors are key players to promote biofertilizers as eco-friendly and cost-effective alternatives to chemical fertilizers.

Sulfur oxidation stands as a pivotal process within the Earth’s sulfur cycle, in which Acidithiobacillus species emerge as skillful sulfur-oxidizing bacteria. They are able to efficiently oxidize several reduced inorganic sulfur compounds (RISCs) under extreme conditions for their autotrophic growth. This unique characteristic has made these bacteria a useful tool in bioleaching and biological desulfurization applications. Extensive research has unraveled diverse sulfur metabolism pathways and their corresponding regulatory systems. The metabolic arsenal of the Acidithiobacillus genus includes oxidative enzymes such as: (i) elemental sulfur oxidation enzymes, like sulfur dioxygenase (SDO), sulfur oxygenase reductase (SOR), and heterodisulfide reductase (HDR-like system); (ii) enzymes involved in thiosulfate oxidation pathways, including the sulfur oxidation (Sox) system, tetrathionate hydrolase (TetH), and thiosulfate quinone oxidoreductase (TQO); (iii) sulfide oxidation enzymes, like sulfide:quinone oxidoreductase (SQR); and (iv) sulfite oxidation pathways, such as sulfite oxidase (SOX). This review summarizes the current state of the art of sulfur metabolic processes in Acidithiobacillus species, which are key players of industrial biomining processes. Furthermore, this manuscript highlights the existing challenges and barriers to further exploring the sulfur metabolism of this peculiar extremophilic genus.

The effect of climate change on flora and fauna has been widely discussed for years. However, its consequences on microorganisms are generally poorly considered. The main effect of climate change on microbiota is related to biodiversity changes in different regions of the planet, mainly due to variations in temperature. These alterations are resulting in a worldwide (re)distribution of pathogens, which was not considered a few years ago. They mainly affect different food chain sectors (such as agriculture, livestock and fishing), as well as human health. Hence, the spread of numerous animal and plant pathogens has been observed in recent years from south to north (especially in America, Europe and Asia), leading to the spread of numerous plant and animal diseases, which results in economic and ecological losses. In addition, global warming that accompanies climate change could also be related to emerging antibiotic resistance. However, the mitigation of climate change goes hand in hand with microorganisms, which can help us through different natural and industrial processes. Thus, this manuscript presents the direct and indirect effects of climate change on microorganisms described up to date and how they act on this worldwide phenomenon.