https://www.um.edu.mt/library/oar/handle/123456789/416 2026-04-09T21:44:10Z 2026-04-09T21:44:10Z Zammit, Gabrielle Fenech, Kristina Sinagra, Emmanuel https://www.um.edu.mt/library/oar/handle/123456789/144993 2026-03-18T06:53:13Z 2026-01-01T00:00:00Z

Title: Responses of biofilm-forming halophilic Calothrix and Coelastrella strains to environmental stressors associated with climate change Authors: Zammit, Gabrielle; Fenech, Kristina; Sinagra, Emmanuel Abstract: Research into the effects of environmental stressors associated with global climate change (GCC) on cyanobacteria and microalgae is scarce, with bloom-forming planktonic cyanobacteria being the exception. This study aimed to address the issue by assessing morphological and biochemical changes in cyanobacterial and microalgal cells exposed to an increased temperature (T), ultraviolet radiation (UVR) and carbon dioxide (CO2) concentration. The strains selected were Calothrix sp. SLM0211 and Coelastrella sp. SLM0503, which were isolated from a coastal environment in the central Mediterranean island of Malta. Elevated UVR had a pronounced effect on Calothrix sp. filaments, which produced screening compounds and resorted to trichome coiling to enhance self-shading. Enhanced growth was observed in cultures of Calothrix sp. grown at an increased CO2 concentration, which produced significantly high amounts of biomass, chlorophylls and carotenoids. An increased T resulted in stunted growth and low biomass accumulation in both strains. Each strain exhibited a unique response to T and UVR stressors, which stimulated the production of exopolymeric substances (EPS) and mycosporine-like amino acids (MAAs) in cultures of Calothrix sp. and lipid production in Coelastrella sp. cells. Our findings indicate that the effects of stressors related to GCC on cyanobacterial and microalgal cells are strain-specific, making changes at community and ecosystem levels difficult to predict.

2026-01-01T00:00:00Z Wichard, Thomas Mapelli-Brahm, Paula Barba, Francisco J. Domingues, Rosario Guttmann, Lior Hutarova, Lenka Loureiro, Joana A. Unal, Dilek Koseoglu-Yilmaz, Pelin Zammit, Gabrielle Meléndez Martínez, Antonio J. https://www.um.edu.mt/library/oar/handle/123456789/144992 2026-03-18T06:46:04Z 2026-01-01T00:00:00Z

Title: Green seaweed Ulva spp. bioprocessing : bioactive molecules, emerging extraction technologies, and industrial applications in the circular bioeconomy Authors: Wichard, Thomas; Mapelli-Brahm, Paula; Barba, Francisco J.; Domingues, Rosario; Guttmann, Lior; Hutarova, Lenka; Loureiro, Joana A.; Unal, Dilek; Koseoglu-Yilmaz, Pelin; Zammit, Gabrielle; Meléndez Martínez, Antonio J. Abstract: Ulva spp., commonly known as sea lettuce, are versatile green macroalgae that offer strong potential for integration into emerging blue and circular bioeconomies. Ulva is a fast-growing and nutrient-tolerant species that produces renewable biomass rich in bioactive compounds with economic potential. This review summarizes advances in the characterization, extraction, and industrial utilization of Ulva biomass, highlighting opportunities for scalable biorefinery approaches. Key bioactive classes include sulfated polysaccharides (ulvans), proteins and peptides, polyunsaturated fatty acids, pigments, and phenolic compounds, which exhibit diverse antioxidant, antimicrobial, and anti-inflammatory properties. Recent developments in green extraction technologies, such as ultrasound-, microwave-, and enzyme-assisted methods, as well as supercritical fluids and deep eutectic solvents, have improved yields in processing Ulva biomass while reducing environmental impact. Beyond laboratory studies, industrial applications are expanding across the food, cosmetic, pharmaceutical, and biomaterial sectors, supported by growing interest in sustainable marine ingredients. However, challenges remain in biomass standardization, taxonomy, large-scale cultivation, and regulatory approval. Integrating Ulva within a circular bioeconomy requires harmonized methodologies and life-cycle assessments to ensure economic and environmental sustainability. Ulva spp. combine rapid growth, carbon capture, and a unique spectrum of bioactive compounds, making them a versatile and scalable marine feedstock for sustainable, circular biorefineries across food, health, and material applications.

2026-01-01T00:00:00Z Liu, Junyu Lin, Yehao Yi, Xudong Zhang, Min Panichayupakaranant, Pharkphoom Buhagiar, Joseph A. Chen, Haixia https://www.um.edu.mt/library/oar/handle/123456789/143918 2026-02-20T13:44:51Z 2026-01-01T00:00:00Z

Title: Potential involvement of PI3K/AKT signaling pathway in the protective effects of rhinacanthus nasutus against diabetic nephropathy-induced oxidative stress Authors: Liu, Junyu; Lin, Yehao; Yi, Xudong; Zhang, Min; Panichayupakaranant, Pharkphoom; Buhagiar, Joseph A.; Chen, Haixia Abstract: Oxidative stress is a primary driver of diabetic nephropathy (DN), highlighting the urgent need for potent natural antioxidants. This study explored the reno-protective potential and associated mechanisms of Rhinacanthus nasutus aqueous extract (AE). Phytochemical profiling via Q Exactive HF Orbitrap LC–MS/MS and serum pharmacochemistry analysis identified 38 constituents, among which 25 bioavailable constituents (e.g., caffeic acid and naringenin) might be the key bioactive ones. In the L6 myotubes in vitro assays, AE (75 µg/mL) was observed to upregulate the PI3K/AKT and GLUT4 signaling cytokines, coinciding with enhanced glucose uptake, as confirmed by Western blot with insulin as a positive control. Furthermore, in STZ-induced DN rats, AE could reduce MDA levels (0.58 vs. 1.44 nmol/mgprot) and restore T-SOD, CAT, and GSH-Px levels (170.57, 51.93, 63.68 vs. 114.93, 40.84, 50.99 mgprot). The protective effects were accompanied by the modulation of PI3K/AKT/mTOR signaling axis. These findings suggest that AE exerts dual efficacy involving glucose uptake regulation and oxidative stress inhibition. Consequently, Rhinacanthus nasutus represents a promising natural antioxidant resource with potential for the management of DN.

2026-01-01T00:00:00Z Scicluna, Antonia Schembri, Patrick J. https://www.um.edu.mt/library/oar/handle/123456789/143754 2026-02-25T12:35:48Z 2026-01-01T00:00:00Z

Title: A burning issue : interactions of the bearded fireworm Hermodice carunculata with artisanal fisheries - a case study from Malta (Central Mediterranean) Authors: Scicluna, Antonia; Schembri, Patrick J. Abstract: The bearded fireworm Hermodice carunculata (Polychaeta) has become increasingly problematic in Mediterranean artisanal fisheries, yet remains understudied. This study provides a detailed analysis of interactions between H. carunculata and artisanal fishers in Marsaxlokk, Malta’s largest fishing village. Combining fisher interviews (local ecological knowledge) and field data, the study reveals that fishing practices inadvertently sustain and amplify local fireworm populations by discarding worms and by-catch nearshore, thereby providing abundant food sources. The highest fisher activity correlated with significantly denser fireworm populations and smaller-sized individuals, indicating population growth driven by fisher practices. Fireworm predation significantly impacts fishers economically, causing an estimated direct loss of 52.5% of the expected profit across the five onboard sessions, due to damaged catch, along with additional indirect losses from reduced gear efficiency and increased labor. The worm’s painful sting adds further nuisance and discomfort for fishers who frequently handle infested gear. Despite awareness of fireworm behavior, fishers largely did not recognize their practices as exacerbating the issue, creating a feedback loop perpetuating the problem. Behavioral experiments suggested that modifying fishing practices and gear design might mitigate fireworm impacts. Addressing this socio-ecological challenge requires further targeted research, education, and policy support to break the cycle that benefits fireworm proliferation in the region to the detriment of fishers.

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