Search Results (5)

Metal oxide nanoparticles, such as ZnONPs and TiO₂NPs, are increasingly applied in various industries. However, their effects on photosynthetic microorganisms at environmentally relevant concentrations remain poorly understood. This study evaluated the impact of ZnONPs and TiO₂NPs, at concentrations ranging from 0.1 to 30 mg/L, on the cyanobacterium Nostoc linckia (strain CNMN-CB-03), a species recognized for its adaptability and biotechnological potential. The nanoparticles were added to controlled cultures, and changes in biomass composition and pigment content were assessed using spectrophotometric assays. Both nanoparticle types significantly affected the physiological and biochemical profile of Nostoc linckia. Low concentrations of ZnONPs stimulated the accumulation of biomass, chlorophyll, carotenoids, and lipids, while higher doses caused a reduction in phycocyanin and in total phycobiliproteins content. TiO₂NPs consistently promoted biomass growth across all tested concentrations, with decrease in carotenoids and total phycobiliproteins observed at the highest concentrations. For both nanoparticle types, malondialdehyde (MDA) levels decreased compared to the control, indicating reduced oxidative stress and effective cellular adaptation. The results highlight the remarkable resilience and metabolic flexibility of Nostoc linckia in the presence of nanoparticles, supporting its potential as a biotechnological platform for the sustainable production of valuable metabolites under controlled stress conditions. Full article

Six new nostocyclophanes and four known compounds have been isolated from Nostoc linckia (Nostocaceae) cyanobacterial strain UTEX B1932. The new compounds, nostocyclophanes E–J (1–6), were characterized by NMR and MS techniques. The known compounds were nostocyclophanes B–D, previously isolated from this strain, and dedichloronostocyclophane D. Structural modifications on the new [7.7]paracyclophane analogs 1–5, isolated from the 80% methanol fraction, range from simple changes such as the lack of methylation or halogenation to more unusual modifications such as those seen in nostocyclophane H (4), in which the exocyclic alkyl chains are of different length; this is the first time this modification has been observed in this family of natural products. In addition, nostocyclophane J (6) is a linear analog in which C-20 is chlorinated in preparation for the presumed enzymatic Friedel–Craft cyclization needed to form the final ring structure, analogous to the biosynthesis of the related cylindrocyclophanes. Nostocyclophane D, dedichloronostocyclophane D, and nostocyclophanes E-J demonstrated moderate to weak growth inhibition against MDA-MB-231 breast cancer cells. Full article

Soil and water pollution is a major problem that has a negative impact on ecosystems and human health in particular. In the bioremediation processes, the application of photosynthetic microorganisms, including cyanobacteria, is a direction of action addressed with increasing frequency in the context of further development and improvement of environmentally friendly techniques needed for detoxification of soils and waters polluted with low concentrations of toxic elements, since they pose a challenge for traditional treatment methods. In the present study, the removal of copper and other metal ions from multielement systems by three generations of Nostoc linckia is discussed. Changes in the biochemical composition of the nostoc biomass, which accumulates metal ions, were monitored. Neutron activation analysis was applied to assess Cu, Fe, Ni, and Zn accumulation by biomass, as well as to determine the biochemical composition of biomass after specific biochemical methods were used. The capacity of the accumulation of copper and other metal ions from multi-elemental systems by cyanobacteria Nostoc linckia was high and increased over two cycles of biomass growth in the systems Cu-Fe-Ni and Cu-Fe-Zn and over three cycles in Cu-Fe and Cu-Fe-Ni-Zn systems. It constituted 1720–10,600 µg metal/g depending on the system and cycle of cultivation. The accumulation of Fe, Ni, and Zn also increased over the generations of nostoc. The process of metal accumulation was demonstrated by a significant change in the biomass biochemical composition. Cyanobacteria Nostoc linckia possess a pronounced capacity of copper and other metal ion accumulation from multimetal systems and showed an increased resistance in environments polluted with heavy metals. Full article

Anthropogenic activity is the main factor contributing to soil pollution with various toxic metals, including Cr(VI), which dictates the need for decontamination. Often, the traditionally used remediation methods (soil removal, stabilization/solidification, physicochemical extraction, and soil washing) are not sufficiently efficient. Among gentle soil remediation, options can be considered. The aim of this study is to assess the ability of Nostoc linckia to remediate soils contaminated with Cr(VI) in association with other metals. Metal uptake by biomass was assessed using neutron activation analysis, while the components of Nostoc biomass were determined using specific methods. The capacity to accumulate chromium from the contaminated environment (Cr in association with Fe, Ni, Cu, and Zn) by the Nostoc linckia is kept at a high level for three generations of cyanobacterium, and the capacity to accumulate Fe, Ni, Cu, and Zn is growing over the cultivation cycles. The process of accumulation of heavy metals is associated with significant changes in the biochemical composition of Nostoc biomass. Due to the high bioaccumulation capacity and the specific growth mode with the formation of crusts on the soil surface, the edaphic cyanobacteria Nostoc linckia is an important candidate for the bioremediation of soil contaminated with chromium in association with other metals. Full article

The objective of the present study is to determine the antioxidant and anticancer activities of Nostoc linckia extracts cultivated under heavy metal stress conditions (0.44, 0.88, and 1.76 mg/L for zinc and 0.158, 0.316, 0.632 mg/L for copper). Phycobiliprotein, phenolic compounds, flavonoids, and tannins were measured. Active ingredients of extracts were evaluated by GC-mass spectroscopy. The obtained results revealed that higher zinc and copper concentrations showed growth inhibition while 0.22 mg/L (Zn) and 0.079 mg/L (Cu) enhanced growth, reaching its maximum on the 25th day. Increases in catalase, lipids peroxidation, and antioxidants, as well as tannins and flavonoids, have been induced by integration of 0.88 mg/L (Zn) and 0.316 mg/L (Cu). Elevation of Zn concentration induced augmentation of antioxidant activity of crude extract (DPPH or ABTS), with superior activity at 0.44 mg/L zinc concentration (81.22%). The anticancer activity of Nostoc linckia extract (0.44 mg/L Zn) tested against four cancer cell lines: A549, Hela, HCT 116, and MCF-7. The extract at 500 µg/mL appeared the lowest cell viability of tested cell lines. The promising extract (0.44 mg/L Zn) recorded the lowest cell viability of 25.57% in cervical cell line, 29.74% in breast cell line, 33.10% in lung cell line and 34.53% in the colon cell line. The antioxidant active extract showed significant stability against pH with attributed increase in antioxidant activity in the range between 8–12. The extract can be used effectively as a natural antioxidant and anticancer after progressive testing. Full article