Extraction and Fractionation of Bioactives from Dipsacus fullonum L. Leaves and Evaluation of Their Anti-Borrelia Activity

Lyme disease (LD) is a tick-borne bacterial disease that is caused by Borrelia burgdorferi. Although acute LD is treated with antibiotics, it can develop into relapsing chronic form caused by latent forms of B. burgdorferi. This leads to the search for phytochemicals against resistant LD. Therefore, this study aimed to evaluate the activity of Dipsacus fullonum L. leaves extract (DE) and its fractions against stationary phase B. burgdorferi in vitro. DE showed high activity against stationary phase B. burgdorferi (residual viability 19.8 ± 4.7%); however, it exhibited a noticeable cytotoxicity on NIH cells (viability 20.2 ± 5.2%). The iridoid-glycoside fraction showed a remarkable anti-Borrelia effect and reduced cytotoxicity. The iridoid-glycoside fraction was, therefore, further purified and showed to contain two main bioactives—sylvestrosides III and IV, that showed a considerable anti-Borrelia activity being the least toxic to murine fibroblast NIH/3T3 cells. Moreover, the concentration of sylvestrosides was about 15% of DE, endorsing the feasibility of purification of the compounds from D. fullonum L. leaves.

Production of Scenedesmus almeriensis Using Pilot-Scale Raceway Reactors Located inside a Greenhouse

The microalga S. almeriensis was produced in spring and summer using 80 m2 raceway reactors located inside a greenhouse in Almería, Spain. This microalga was selected because it is a fast-growing and robust strain with potential applications in the production of functional foods and feeds or as a high-value agricultural biostimulant. Overall, the biomass productivity obtained in summer was 24.9 ± 0.9 g·m−2·day−1. This value was higher than that obtained in spring, with an average value of 21.4 ± 1.3 g·m−2·day−1 (p < 0.05). The Fv/Fm value of the cultures at the stationary phase was comparable and around 0.6, which is the optimum of this strain. No major differences in the macromolecular composition of the biomass were observed between seasons, with an average protein, lipid, ash, and carbohydrate content of 37.9, 4.6, 10.8, and 46.7%, respectively. The data reported herein were used to validate a previously described model. The differences between the experimental and the predicted biomass productivities were below 5% in spring and 8% in summer, although a larger dataset is needed to validate the model. Overall, results supported the robustness of the selected strain and its utilisation in different industrial sectors.

Transcriptional Shift and Metabolic Adaptations during Leishmania Quiescence Using Stationary Phase and Drug Pressure as Models

Microorganisms can adopt a quiescent physiological condition which acts as a survival strategy under unfavorable conditions. Quiescent cells are characterized by slow or non-proliferation and a deep downregulation of processes related to biosynthesis. Although quiescence has been described mostly in bacteria, this survival skill is widespread, including in eukaryotic microorganisms. In Leishmania, a digenetic parasitic protozoan that causes a major infectious disease, quiescence has been demonstrated, but the molecular and metabolic features enabling its maintenance are unknown. Here, we quantified the transcriptome and metabolome of Leishmania promastigotes and amastigotes where quiescence was induced in vitro either, through drug pressure or by stationary phase. Quiescent cells have a global and coordinated reduction in overall transcription, with levels dropping to as low as 0.4% of those in proliferating cells. However, a subset of transcripts did not follow this trend and were relatively upregulated in quiescent populations, including those encoding membrane components, such as amastins and GP63, or processes like autophagy. The metabolome followed a similar trend of overall downregulation albeit to a lesser magnitude than the transcriptome. It is noteworthy that among the commonly upregulated metabolites were those involved in carbon sources as an alternative to glucose. This first integrated two omics layers afford novel insight into cell regulation and show commonly modulated features across stimuli and stages.