Current Issues in Molecular Biology

Refractory infections caused by multidrug-resistant bacteria have emerged as a substantial threat to public health, prompting renewed interest in phage therapy. Bacteria and phages are ubiquitous in diverse environments, engaging in continuous interaction and co-evolution. In response to phage infection, bacteria have developed an array of defense mechanisms. Current studies on bacteria–phage interactions predominantly focus on laboratory settings using artificial media, whereas the final goal of phage therapy—to combat antibiotic-resistant bacteria—lies in its clinical application. This review describes bacterial defense strategies against phage infection in the context of laboratory-based artificial media, animal experiments and clinical cases, aiming to deepen the understanding of bacteria–phage interactions and promote the advancement of effective phage therapy for clinical applications.

Oxidative and nitrosative stress are key contributors to the development and progression of chronic inflammatory disorders, cancer and neurodegenerative diseases (viz., Alzheimer’s disease). Cholinergic dysfunction is a major hallmark of Alzheimer’s disease and is closely associated with these processes. Red seaweeds are rich in bioactive compounds that have been increasingly investigated for their potential to modulate these processes. This review aims to examine the role of major red seaweed-derived metabolites in regulating redox imbalance, immunomodulatory capacity and acetylcholinesterase activity, with emphasis on in vitro studies. An analysis of peer-reviewed literature was conducted, focusing on chemical, biochemical and cell-based assays. Studies assessed antioxidant activity, anti-inflammatory and immunostimulatory effects, and acetylcholinesterase inhibition of isolated compounds/fractions of red seaweed using established methods, including radical scavenging assays, Griess-based nitrite assay and enzyme inhibition assays. Sulfated polysaccharides, oligosaccharides, mycosporine-like amino acids (MAAs), phycoerythrin, bromophenols, phlorotannin and terpenoid-derived metabolites demonstrated antioxidant capacity through radical scavenging, metal chelation and modulation of endogenous antioxidants. They also modulated inflammatory mediators, including nitric oxide and pro-inflammatory cytokines, and inhibited acetylcholinesterase (AChE) activity. In vitro evidence supports red seaweed-derived compounds as promising modulators of redox homeostasis, inflammation and cholinergic function, highlighting their relevance as functional food ingredients, while underscoring the need for in vivo and clinical validation.

Acute lung injury (ALI) is a severe inflammatory condition with high mortality rates, necessitating the development of effective therapeutic agents. Polydeoxyribonucleotide (PDRN), a DNA-derived compound known for its tissue repair and anti-inflammatory properties, has gained attention as a potential therapeutic agent. However, the efficacy of PDRN derived from marine sources, particularly Porphyra sp. (laver), remains unexplored in respiratory inflammation. In this study, we investigated the protective effects of Porphyra sp.-derived PDRN (Ps-PDRN) against LPS-induced ALI in mice through two administration routes: intranasal (IN) and oral (PO). Ps-PDRN treatment significantly attenuated fever, pulmonary edema, and histopathological changes in LPS-challenged mice. Both IN and PO administration of Ps-PDRN markedly reduced proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokines (MCP-1, RANTES, CXCL1, and MIP-2) in bronchoalveolar lavage fluid (BALF) and serum. Comparative analysis of the two administration routes revealed distinct efficacy profiles, with oral administration demonstrating superior chemokine inhibition, while intranasal delivery showed advantages in certain cytokine suppression. Histological examination revealed that Ps-PDRN preserved alveolar architecture and reduced inflammatory cell infiltration. Furthermore, in vitro studies using RAW 264.7 macrophages demonstrated that Ps-PDRN inhibited LPS-induced production of proinflammatory cytokines, such as TNF-α and IL-6, in a dose-dependent manner. These findings suggest that Ps-PDRN exerts potent anti-inflammatory effects against ALI through both local and systemic administration routes, highlighting its potential as a novel therapeutic agent for inflammatory lung diseases.