Microalgae, historically relevant to aquaculture sector, can effectively contribute to the sustainability in several production chain. The physical and chemical environmental factors play a direct or indirect role in shaping the composition of their intracellular compounds of these organisms. Among these compounds, fatty acids are particularly noteworthy, with various species harboring an extensive array of them. Notably, the marine dinoflagellate Prorocentrum micans excels in the production of essential polyunsaturated fatty acids (PUFA), including DHA and EPA. The objective was to determine which factors contribute to the accumulation of the PUFA in a P. micans strain. A factorial design of 3x3 composed by the following factors: illumination (5, 12.5, 20 µmol photons m-2 s-1), nitrate dose (0, 75, 150 mg ml-1) and inoculum volume (50, 125, 200 ml) was examined to determine the better growth conditions for P. micans. Furthermore, lipid profile and the fatty acids profile were analyzed at the end of the cultivation. The results determined that, maximum averages of DHA (20%) and EPA (1%), in the biomass, were registered in cultures without nitrate, low irradiance (5 µmol photons m-2 s-1) and high volume of inoculum (200 ml). The maximum cell concentration recorded was 3.1×104 cells ml-1, at the end of the culture. So, it can be concluded that the evaluated strain is easily adapted to the culture flow and, the culture conditions to which it was subjected allows its biomass to be considered an interesting alternative as lipid input in aquaculture activity.

Microalgae interact with mineral particles in aqueous environment, yet how clay minerals affect physiological processes in algal cells remain unexplored. In this study, we compared the effects of palygorskite (Pal) and montmorillonite (Mt), which respectively represent fibrous and layered clay minerals, on the physiological processes of Chlamydomonas reinhardtii. It was observed that C. reinhardtii responded differently to the treatments of Pal and Mt. The Pal particles bound tightly to and even inserted cells, resulting in a significantly decrease of cell numbers from 27.35 to 21.02*107 mL-1. However, Mt was only loosely attached to the cell surface. The photosynthesis in the algal cells was greatly inhibited by Pal, with rETRmax significantly reduced from 103.80 to 56.67 μmol electrons m-2s-1 and downregulation of IF2CP, psbH and OHP1, which were key genes involved in photosynthesis. In addition, Pal reduced the quantities of proteins and polysaccharides in extracellular polymeric substances (EPS) and the P uptake by C. reinhardtii when the P level in the culture was 3.15 mg/L. However, no significant changes were found regarding the above EPS components or the amount of P in algal cells upon the addition of Mt. Together, the impacts of fibrous Pal on C. reinhardtii was more profound than those of layered Mt.

Escherichia Coli ( E. coli) is one of the most prevalent bacteria in the gut and plays an important role in the formation of the intestinal microbiome. In this study, Escherichia phage Ioannina, a novel member of Caudoviricetes, with high lytic activity against E. coli ATCC 25922, was isolated from hospital wastewater. Escherichia phage Ioannina was highly resistant to a broad range of temperatures and alkaline pH, but was sensitive to acidic pH. Whole genome sequencing of the phage, revealed that Escherichia phage Ioannina is a novel phage within the Dhillonvirus genus. Its genome is a 45,270 bp double-stranded DNA molecule that encodes 64 putative open reading frames (ORFs). The phylogenetic analysis of open reading frames, which diversified Escherichia phage Ioannina from other dhillonviruses, indicated that ORF31 (a putative tail fiber protein) presented higher similarity to representatives of other phage families. ORF31 was significantly more related to similar ORFs belonging to the Kuravirus and Tunavirus ( Drexlerviridae) genera, indicating a possible recombination event.

The capacity to form biofilms is a common trait among many microorganisms present on Earth. In this study, we demonstrate for the first time that the fatal pine pitch canker agent, Fusarium circinatum, can lead a biofilm-like lifestyle with aggregated hyphal bundles wrapped in extracellular matrix (ECM). Our study suggests that F. circinatum biofilms respond to a changing environment, demonstrated by poor and optimal biofilm development under particular abiotic conditions, including temperature and pH. Further analysis revealed that while planktonic cells produced small amounts of ECM per unit of the biomass, heat- and azole-exposed biofilms produced significantly more ECM than non-exposed biofilms. The increased synthesis of ECM in biofilms due to these abiotic factors underscores biofilm importance in response to various stress conditions, demonstrating the adaptability of F. circinatum to changing environments. Interestingly, azole exposure also led to biofilms that were resistant to DNase, which typically uncouples biofilms by penetrating the biofilm and degrading its extracellular DNA; we propose that DNases were likely hindered from reaching target cells by the ECM barricade. The interplay between antifungal treatment and DNase enzyme suggests a complex relationship between eDNA, ECM, and antifungal agents in F. circinatum biofilms. Therefore, our results show how a phytopathogen’s sessile (biofilm) lifestyle could influence its response to the surrounding environment.