SynBio, Volume 3, Issue 2 (June 2025) – 2 articles

Polyamines play a pivotal role in regulating the growth and metabolic adaptation of microalgae, yet their integrative regulatory roles remain underexplored. This review advances a comprehensive perspective of microalgae growth, integrating polyamine dynamics, amino acid metabolism, and redox balance. Polyamines (putrescine, spermidine, and spermine) biology in microalgae, particularly Chlamydomonas reinhardtii, is reviewed, exploring their critical function in modulating cell cycle progression, enzymatic activity, and stress responses through nucleic acid stabilization, protein synthesis regulation, and post-translational modifications. This review explores how the exogenous supplementation of polyamines modifies their intracellular dynamics, affecting growth phases and metabolic transitions, highlighting the complex regulation of internal pools of these molecules. Comparative analyses with Chlorella ohadii and Scenedesmus obliquus indicated species-specific responses to polyamine fluctuations, linking putrescine and spermine levels to important tunable metabolic shifts and fast growth phenotypes in phototrophic conditions. The integration of multi-omic approaches and computational modeling has already provided novel insights into polyamine-mediated growth regulation, highlighting their potential in optimizing microalgae biomass production for biotechnological applications. In addition, genomic-based modeling approaches have revealed target genes and cellular compartments as bottlenecks for the enhancement of microalgae growth, including mitochondria and transporters. System-based analyses have evidenced the overlap of the polyamines biosynthetic pathway with amino acids (especially arginine) metabolism and Nitric Oxide (NO) generation. Further association of the H₂O₂ production with polyamines metabolism reveals novel insights into microalgae growth, combining the role of the H₂O₂/NO rate regulation with the appropriate balance of the mitochondria and chloroplast functionality. System-level analysis of cell growth metabolism would, therefore, be beneficial to the understanding of the regulatory networks governing this phenotype, fostering metabolic engineering strategies to enhance growth, stress resilience, and lipid accumulation in microalgae. This review consolidates current knowledge and proposes future research directions to unravel the complex interplay of polyamines in microalgal physiology, opening new paths for the optimization of biomass production and biotechnological applications. Full article

The SARS-CoV-2 virus, which causes COVID-19, has rapidly evolved, producing highly transmissible variants like Omicron. Non-structural protein 6 (NSP6) is essential for viral replication and immune evasion. This study analyzed the NSP6 protein of the Omicron variant, focusing on conserved motifs, mutations, and residual properties to better understand its structure, function, and potential for immune evasion. Sequences from humans in South America were obtained from GISAID and aligned using Clustal Omega 1.2.4, with mutations identified by a Python 3 algorithm and conserved motifs detected using the MEME tool. Sequence diversity was assessed with Shannon’s entropy, while hydrophilicity, flexibility, accessibility, and antigenicity were analyzed using EMBOSS PEPSTATS and Expasy’s ProtScale tools. Phylogenetic analysis was performed with IQ-TREE software. Analysis of 161 NSP6 protein sequences revealed significant divergence from the reference sequence, with mutations proximal to conserved regions indicating potential functional and structural changes. The analysis also identified distinct hydrophobic and hydrophilic regions, with specific amino acid positions showing high flexibility and antigenicity. Phylogenetic analysis identified three clades with varying degrees of similarity to the reference sequence. This comprehensive study of the NSP6 protein in the Omicron variant provides insights into its role in viral replication and immune evasion, contributing to the development of targeted interventions against COVID-19. Full article