We characterized the oxidative stress response of Candida glabrata to better understand the virulence of this fungal pathogen. C. glabrata could withstand higher concentrations of H 2 O 2 than Saccharomyces cerevisiae and even Candida albicans. Stationary-phase cells were extremely resistant to oxidative stress, and this resistance was dependent on the concerted roles of stress-related transcription factors Yap1p, Skn7p, and Msn4p. We showed that growing cells of C. glabrata were able to adapt to high levels of H 2 O 2 and that this adaptive response was dependent on Yap1p and Skn7p and partially on the general stress transcription factors Msn2p and Msn4p. C. glabrata has a single catalase gene, CTA1, which was absolutely required for resistance to H 2 O 2 in vitro. However, in a mouse model of systemic infection, a strain lacking CTA1 showed no effect on virulence.

The Precambrian era is associated with the origin of life on primitive Earth. It was, in fact, in that era that ribonucleic acid (RNA) was first acquired. From this evolved the genomic deoxyribonucleic acid (DNA) that later generated the biomolecules that formed the first cell. In this way, with the ongoing changes in environmental factors, the first cells evolved to give rise to higher multicellular organisms, i.e., plants and animals. Radiolarians and diatoms are organisms that have been conserved since the Precambrian era. However, although these organisms are alive (they can be considered as living fossils), they do not suffice to explain the origin of life. To understand the origin of life, the interactions among inorganic compounds that existed in the Precambrian era must be elucidated. In this context, calcium, barium, or strontium silico-carbonates (usually called silica-biomorphs) have been simply named biomorphs that emulate the morphologies of organisms, such as flowers, leaves, stems, helices, worms, radiolarians, and diatoms, among others. The shapes of the biomorphs can be implicated in the origin of life due to their similarity with the shapes of the cherts of the Precambrian era. However, biomorphs are inorganic compounds that do not contain any organic biomolecules such as nucleic acids or proteins inside their chemical structures. The aim of the present work was to synthesize calcium, barium, or strontium silica biomorphs in the presence of nucleic acids: genomic DNA (linear double helices), plasmid DNA (circular helices), and RNA (a single chain helix). The morphology of these biomorphs was assessed through scanning electron microscopy (SEM). The obtained microphotographs revealed that nucleic acids direct the synthesis of biomorphs toward a unique and specific structure for each of these biomolecules. The chemical composition and the crystalline structure were determined through micro-Raman spectroscopy and X-ray diffraction to characterize the most characteristic crystalline phases. The biomorphs obtained from calcium, barium, or strontium corresponded to crystalline structures of CaCO 3 (calcite, aragonite, vaterite), BaCO 3 (witherite), or SrCO 3 (strontianite), respectively. These silica-carbonates (considered as reminiscence of the shape found in the cherts of the Precambrian) can be a linking point between the Precambrian era and the subsequent eras. To the best of our knowledge, this is the first report in which the interaction of nucleic acids in the synthesis of biomorphs has been evaluated.

In this contribution we use nonconventional methods that help to increase the success rate of a protein crystal growth, and consequently of structural projects using Xray diffraction techniques. In order to achieve this purpose, this contribution presents new approaches involving more sophisticated techniques of protein crystallization, not just for growing protein crystals of different sizes by using electric fields, but also for controlling crystal size and orientation. This latter was possible through the use of magnetic fields that allow to obtain protein crystals suitable for both high-resolution X-ray and neutron diffraction crystallography where big crystals are required. This contribution discusses some pros, cons and realities of the role of electromagnetic fields in protein crystallization research, and their effect on protein crystal contacts. Additionally, we discuss the importance of room and low temperatures during data collection. Finally, we also discuss the effect of applying a rather strong magnetic field of 16.5 T, for shorts and long periods of time, on protein crystal growth, and on the 3D structure of two model proteins.

Biofilms of Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis are associated with high indices of hospital morbidity and mortality. Major factors involved in the formation and growth of Candida biofilms are the chemical composition of the medical implant and the cell wall adhesins responsible for mediating Candida–Candida, Candida–human host cell and Candida–medical device adhesion. Strategies for elucidating the mechanisms that regulate the formation of Candida biofilms combine tools from biology, chemistry, nanoscience, material science and physics. This review proposes the use of new technologies, such as synchrotron radiation, to study the mechanisms of biofilm formation. In the future, this information is expected to facilitate the design of new materials and antifungal compounds that can eradicate nosocomial Candida infections due to biofilm formation on medical implants. This will reduce dissemination of candidiasis and hopefully improve the quality of life of patients.

Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis are able to form biofilms on virtually any biomaterial implanted in a human host. Biofilms are a primary cause of mortality in immunocompromised and hospitalized patients, as they cause recurrent and invasive candidiasis, which is difficult to eradicate. This is due to the fact that the biofilm cells show high resistance to antifungal treatments and the host defense mechanisms, and exhibit an excellent ability to adhere to biomaterials. Elucidation of the mechanisms of antifungal resistance in Candida biofilms is of unquestionable importance; therefore, this review analyzes both the chemical composition of biomaterials used to fabricate the medical devices, as well as the Candida genes and proteins that confer drug resistance.

The origin of life on Earth is associated with the Precambrian era, in which the existence of a large diversity of microbial fossils has been demonstrated. Notwithstanding, despite existing evidence of the emergence of life many unsolved questions remain. The first question could be as follows: Which was the inorganic structure that allowed isolation and conservation of the first biomolecules in the existing reduced conditions of the primigenial era? Minerals have been postulated as the ones in charge of protecting theses biomolecules against the external environment. There are calcium, barium, or strontium silica–carbonates, called biomorphs, which we propose as being one of the first inorganic structures in which biomolecules were protected from the external medium. Biomorphs are structures with different biological morphologies that are not formed by cells, but by nanocrystals; some of their morphologies resemble the microfossils found in Precambrian cherts. Even though biomorphs are unknown structures in the geological registry, their similarity with some biological forms, including some Apex fossils, could suggest them as the first “inorganic scaffold” where the first biomolecules became concentrated, conserved, aligned, and duplicated to give rise to the pioneering cell. However, it has not been documented whether biomorphs could have been the primary structures that conserved biomolecules in the Precambrian era. To attain a better understanding on whether biomorphs could have been the inorganic scaffold that existed in the primigenial Earth, the aim of this contribution is to synthesize calcium, barium, and strontium biomorphs in the presence of genomic DNA from organisms of the five kingdoms in conditions emulating the atmosphere of the Precambrian era and that CO2 concentration in conditions emulating current atmospheric conditions. Our results showed, for the first time, the formation of the kerogen signal, which is a marker of biogenicity in fossils, in the biomorphs grown in the presence of DNA. We also found the DNA to be internalized into the structure of biomorphs.

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The origin of life from the chemical point of view is an intriguing and fascinating topic, and is of continuous interest. Currently, the chemical elements that are part of the different cellular types from microorganisms to higher organisms have been described. However, although science has advanced in this context, it has not been elucidated yet which were the first chemical elements that gave origin to the first primitive cells, nor how evolution eliminated or incorporated other chemical elements to give origin to other types of cells through evolution. Calcium, barium, and strontium silica-carbonates have been obtained in vitro and named biomorphs, because they mimic living organism structures. Therefore, it is considered that these forms can resemble the first structures that were part of primitive organisms. Hence, the objective of this work was to synthesize biomorphs starting with different mixtures of alkaline earth metals—beryllium (Be2+), magnesium (Mg2+), calcium (Ca2+), barium (Ba2+), and strontium (Sr2+)—in the presence of nucleic acids, RNA and genomic DNA (gDNA). Our results allow us to infer that the stability of calcium followed by strontium had played an important role in the evolution of life since the Precambrian era until our current age. In this way, the presence of these two chemical elements as well as silica (in the primitive life) and some organic molecules give origin to a great variety of life forms, in which calcium is the most common dominating element in many living organisms as we know nowadays.