All organisms that perform oxygenic photosynthesis fix inorganic CO2 through the Calvin-Benson-Bassham (CBB) cycle, which is then converted into many organic...

The industrial development and modernization occurring worldwide are crucial for meeting the demands of the present era. However, the necessary use of xenobiotics, such as heavy metals, dyes, and pesticides, poses a significant threat to ecosystems and inflicts severe harm on the environment. Cyanobacteria play a vital role in nitrogen fixation and are integral to the environment, contributing to soil fertility, UV protection, and oxygen production, among other functions. Despite the ability of these microbes to produce valuable metabolites, their production is sensitive to environmental toxicity. Furthermore, the relationship between photonic wavelength and the photosynthetic activity of cyanobacteria remains poorly understood. This article investigates the connection between the efficiency of the photosystem and the nature of the incident photonic wavelength. Additionally, the study examines the effects of photonic energy on the response of cyanobacteria to Cr (VI) toxicity, highlighting the involvement of an alternative quantum well induced by the presence of Cr (VI). Significantly, the research identifies a clear correlation between the level of photonic energy and the efficiency of the photosystem by calculating various photochemical and physiological parameters, including pigments, dry biomass, quantum yield, and transient S state. The enhancement of water-splitting processes and photosystem II efficiency was also observed with increased photonic energy under blue and green light, leading to a reduction in oxidative damage. These findings suggest a cooperative relationship between specific light wavelengths and the alleviation of Cr (VI) stress in Nostoc commune, providing insights into their ecological adaptability and potential applications in controlled cultivation systems and bioremediation.

The prevention of marine biofouling remains a global challenge due to environmental concerns associated with current biocidal antifouling (AF) agents …

Cyanobacterial blooms (CyanoHABs) and their associated toxins pose a significant threat to public health and water quality. A novel approach called Mu…

Abstract Argonaute proteins are an evolutionarily conserved family of proteins capable of recognizing and cleaving specific nucleic acid sequences using complementary guide molecules. Eukaryotic Argonautes play a key role in RNA interference by utilizing short RNAs of various classes to recognize target mRNAs. Prokaryotic Argonautes are much more diverse and most of them recognize DNA targets. The search for new Argonautes that would be active under varying conditions is important for both understanding their functions and developing new tools for genetic technologies. Many previously studied Argonautes exhibit low activity at low and moderate temperatures. To overcome this limitation, we isolated and studied two Argonaute proteins from psychrotolerant cyanobacteria, CstAgo from Cyanobacterium stanieri and CspAgo from Calothrix sp. Both proteins use short DNA guides to recognize and cleave DNA targets. CstAgo displayed no specificity for the 5′-end structure of the guide, while CspAgo demonstrated a weak preference for the 5′-terminal nucleotide. CstAgo was highly active and capable of cleaving single-stranded DNA at temperatures from 10 to 50°C. CspAgo was more cold-sensitive but cleaved double-stranded plasmid DNA using specific guides. Therefore, the studied proteins can be potentially used for DNA manipulations under a wide range of conditions.

For the filamentous cyanobacteria, the order Leptolyngbyales is the larger and obviously polyphyletic group, although its members are morphologically similar...

Center: Cyanobacterial isoprene production from CO2 and sunlight. Top: CRISPR-editing for generation of markerless production strains. Top right: Long-term production assay for strain stability asses...

Toxic cyanobacterial blooms, primarily caused by Microcystis aeruginosa, are increasing globally due to climate change. These harmful organisms have adapted to high temperature and UV radiation (UVR), posing a significant threat to drinking water. While UVBR can damage cyanobacteria, they may avoid it with antioxidant defense mechanisms. Microcystins (MCs), cyclic hepatotoxic heptapeptides produced by cyanobacteria, can harm aquatic and terrestrial organisms, but their role in antioxidant protection remains unclear. This study investigated the relationship between gene expression and MC content in Microcystis aeruginosa cells pre-adapted to elevated temperatures (29 °C) exposed to natural UVR for several days. We have demonstrated a strong resilience in M. aeruginosa to high doses of UVBR, largely attributed to its enhanced antioxidant capacity following pre-exposure to elevated temperatures, as confirmed by previous studies. Moreover, our findings suggest that MCs may act as scavengers as part of the UVR protection mechanisms. This is evidenced by a temporal lack of correlation between the abundance of mcy transcripts and the cellular toxin content, where toxin quotas were lower despite increased mcy transcription. These findings are particularly relevant to the ecophysiological role of MCs, suggesting its potential involvement in increased blooms of toxic M. aeruginosa under conditions of climate change and eutrophication. This information is crucial for effective water treatment planning.

Cyanophycin is a biopolymer of arginine and aspartate, and it is found in various prokaryotes. Two key enzymes of cyanophycin metabolism are cyanophyc…

This study provides evidence on how carbon metabolism regulates cell division among cyanobacteria. Manipulation of the TCA pathway directly impacts the FtsZ-dependent cell division by regulating its expression via the transcriptional factor NtcA.

Bacteria can organize their internal components in specific patterns to ensure proper function and faithful inheritance after cell division. In the cyanobacterium Synechococcus elongatus, protein-base...

This work first reveals the silicon uptake in Synechococcus PCC 7002 via two silicon transporters SIT-L and Lsi-L, which are widely distributed in 469 sequenced cyanobacterial genomes. This enhances p...

Microbial rhodopsins are photoactive membrane proteins known for transporting small inorganic ions such as H+, Cl–, and Na+. Their compact structure─comprising seven transmembrane helices─has long been thought to limit their substrate range to such ions. Here, we report that several anion-pumping rhodopsins can also transport organic anions. In particular, a rhodopsin from cyanobacteria transports bulky organic anions, including those with a benzene ring, with volumes up to ∼120 Å3─five times larger than Cl–. These anions bind in the dark state and are translocated upon photoactivation, via a mechanism similar to Cl–. Notably, only anions with pKa values below 2 are transported, suggesting that negative charge is essential for binding. This study provides the first evidence that naturally occurring proteins can use light to transport organic compounds across membranes. These findings broaden the functional scope of microbial rhodopsins and open new possibilities for light-driven transport of organic ions.

Isoprenoid quinones constitute a class of redox lipids that are indispensable for electron transfer in a variety of cellular functions. For instance, plastoquinone, an integral component of plants, al...

The aquatic microbiome can influence cyanobacterial harmful algal blooms. Abundances of genes and transcripts for phosphorus acquisition, denitrification and nitrogen fixation were higher upstream, w....

UCYN-B drives high N2 fixation rates in previously unrecognized hot spots across the global ocean, making a significant contribution to the marine nitrogen

Fenoxaprop-p-ethyl is a widely employed aryloxyphenoxypropionate herbicide that inhibits acetyl-CoA carboxylase (ACCase), thus interfering with fatty acid biosynthesis in target organisms. While its ...

Cyanobacteria utilize a CO2-concentrating mechanism (CCM) to enhance photosynthetic efficiency by accumulating CO2 around RuBisCO, a process crucial f…

Cyanobacteria are ecologically pivotal microorganisms with immense biotechnological potential, particularly due to their capacity to synthesize fatty acids, terpenes, and other metabolites with applications ranging from biofuels to nutraceuticals. Despite this, many genera remain genomically underexplored. In this study, we present a polyphasic genomic analysis of two native strains, Aphanothece microscopica RSMan92 and A. stagnina RSMan2012, isolated from the Patos Lagoon estuary in Southern Brazil. Whole-genome sequencing and annotation enabled characterization of both genomes: RSMan92 spans 3.69 Mb in 701 contigs with 3,279 protein-coding sequences, while RSMan2012 comprises 3.28 Mb in 153 contigs with 3,567 protein-coding sequences. Phylogenetic analyses using MUSCLE and RAxML positioned these strains within a well-supported clade closely related to other Aphanothece RefSeq genome, highlighting their evolutionary relatedness and reinforcing the integrative taxonomic placement of the genus. Both strains reveal conserved gene repertoires associated with stress response, fatty acid biosynthesis, and secondary metabolite production (terpenes). Functional classification based on COG and KEGG annotations indicated strong representation of genes involved in lipid metabolism. To investigate how variations in temperature and light intensity modulate metabolite profiles, cultures were subjected to different environmental conditions. GC/EI-MS analysis revealed distinct patterns of fatty acid methyl ester production across conditions: both strains synthesized saturated and monounsaturated fatty acids, whereas only strain RSMan92 exhibited the capacity to synthesize polyunsaturated fatty acids, including linoleic acid derivatives, under variable cultivation conditions. This polyphasic genomic approach, providing novel genomic records, also reveals the fatty acid biosynthetic capacity and metabolic plasticity of Aphanothece strains, emphasizing their biotechnological relevance. Graphical abstract