Uncovering Potential Applications of Cyanobacteria and Algal Metabolites in Biology, Agriculture and Medicine: Current Status and Future Prospects

Nanosynthesis, phycochemical constituents, and pharmacological properties of cyanobacterium Oscillatoria sp

The Oscillatoria sp., a blue-green alga or cyanobacterium, consists of about 305 species distributed globally. Cyanobacteria are prokaryotes possessing several secondary metabolites that have industrial and biomedical applications. Particularly, the published reviews on Oscillatoria sp. have not recorded any pharmacology, or possible details, while the detailed chemical structures of the alga are reported in the literature. Hence, this study considers pertinent pharmacological activities of the plethora of bioactive components of Oscillatoria sp. Furthermore, the metallic nanoparticles produced with Oscillatoria sp. were documented for plausible antibacterial, antifungal, antioxidant, anticancer, and cytotoxic effects against several cultured human cell lines. The antimicrobial activities of solvent extracts of Oscillatoria sp. and the biotic activities of its derivatives, pyridine, acridine, fatty acids, and triazine were structurally described in detail. To understand the connotations with research gaps and provide some pertinent prospective suggestions for further research on cyanobacteria as potent sources of pharmaceutical utilities, attempts were documented. The compounds of Oscillatoria sp. are a potent source of secondary metabolites that inhibit the cancer cell lines, in vitro. It could be expected that by holistic exploitation, the natural Oscillatoria products, as the source of chemical varieties and comparatively more potent inhibitors, would be explored against pharmacological activities with the integument of SARs.

A systematic review on guanitoxin: General characteristics and ecological risks

Guanitoxin (GNT) is a potent cyanotoxin, with a relatively low number of publications (n = 51) compared to other cyanotoxins. Among the published studies, 35 % were on the effect of the toxin in animals, mainly in rodents and in vitro testing, followed by studies that identified species of cyanobacteria that produce GNT in aquatic systems and consequently accidental poisoning in wild and domestic animals (27 %). Studies that developed or tested methods for identifying the molecule, based on colorimetric and analytical techniques, represented 14 %, while 8 % were on GNT biosynthesis. Review articles and chemical isolation (6 %) and on the stability of the molecule (4 %) were the topics with the lowest number of publications. The results show the occurrence of GNT was identified mainly in eutrophic environments with a higher incidence in the American continent. Chemical characteristics of the molecule, such as short half-life in the environment, instability in solutions with alkaline pH values, temperature >23 °C, added to the lack of an analytical standard, are factors that make it difficult to identify and quantify it. However, GNT monitoring can be performed using LC-MS-MRM methods or genes specific to the newly discovered molecule.

Study of pesticidal activity of bioactive compounds of Neowestiellopsis persica strain A1387 in improving the antioxidative and antimicrobial activity of wheat to sunn pest

Cyanobacteria have been recognized for their advantageous impact on plant growth and development. The application of certain techniques has the potential to enhance various aspects of plant development, including growth, yield, proximate content (such as protein and carbohydrate levels), as well as the ability to withstand abiotic stresses such as herbicide exposure. The current investigation focused on examining the influence of bioactive compounds derived from the cyanobacterium Neowestiellopsis persica strain A1387 on enhancing the antioxidant and anyimicrobial activity of wheat plants in their defense against the plant pathogenic Sunn pest. The findings of the study indicate that the levels of H2O2 and GPx in wheat plants that were infected with aphids were significantly elevated compared to the treatments where aphids and cyanobacteria extract were present. The confirmation of these results was achieved through the utilization of confocal and fluorescent microscope tests, respectively. Furthermore, the findings indicated that the constituents of the cyanobacterial extract augmented the plant's capacity to withstand stress by enhancing its defense mechanisms. In a broader context, the utilization of cyanobacterial extract demonstrated the ability to regulate the generation and impact of oxygen (O2) and hydrogen peroxide (H2O2), while concurrently enhancing the functionality of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) enzymes within wheat plants. This facilitation enabled the plants to effectively manage oxidative stress. Moreover, the findings of the antibacterial activity assessment conducted on the extract derived from cyanobacteria demonstrated notable susceptibility. The bacteria that exhibited the highest sensitivity to the extract of cyanobacterium Neowestiellopsis persica strain A1387 were staphylococcus aureus and pseudomonas aeruginosa. Conversely, salmonella typhi demonstrated the greatest resistance to the aforementioned extract. The potential impact of cyanobacteria extract on the antioxidative response of wheat plants to sunn pest infestation represents a novel contribution to the existing body of knowledge on the interaction between wheat plants and aphids.

Effects of nitrogen starvation on growth and biochemical composition of some microalgae species

Nitrogen is one of the most important nutrient sources for the growth of microalgae. We studied the effects of nitrogen starvation on the growth responses, biochemical composition, and fatty acid profile of Dunaliella tertiolecta, Phaeodactylum tricornutum, and Nannochloropsis oculata. The lack of nitrogen caused changes in carbohydrate, protein, lipid, and fatty acid composition in all examined microalgae. The carbohydrate content increased 59% in D. tertiolecta, while the lipid level increased 139% in P. tricornutum under nitrogen stress conditions compared to the control groups. Nitrogen starvation increased the oligosaccharide and polysaccharide contents of D. tertiolecta 4.1-fold and 3.6-fold, respectively. Furthermore, triacylglycerol (TAG) levels in N. oculata and P. tricornutum increased 2.3-fold and 7.4-fold, respectively. The dramatic increase in the amount of TAG is important for the use of these microalgae as raw materials in biodiesel. Nitrogen starvation increased the amounts of oligosaccharides and polysaccharides of D. tertiolecta, while increased eicosapentaenoic acid (EPA) in N. oculata and docosahexaenoic acid (DHA) content in P. tricornutum. The amount of polyunsaturated fatty acids (PUFAs), EPA, DHA, oligosaccharides, and polysaccharides in microalgal species can be increased without using the too costly nitrogen source in the culture conditions, which can reduce the most costly of living feeding.

Harnessing Cyanobacteria's Bioactive Potential: A Sustainable Strategy for Antioxidant Production

Unsaturated diacylglycerols are a class of antioxidant compounds with the potential to positively impact human health. Their ability to combat oxidative stress through radical scavenger activity underscores their significance in the context of preventive and therapeutic strategies. In this paper we highlight the role of Anabaena flos-aquae as a producer of unsaturated mono and diacylglycerols, and then demonstrate the antioxidant activity of its methanolic extract, which has as its main components a variety of acylglycerol analogues. This finding was revealed using a sustainable strategy in which the One Strain Many Compounds (OSMAC) cultivation in microscale was coupled with a bioinformatic approach to analyze a large dataset of mass spectrometry data using the molecular networking analyses. This strategy reduces time and costs, avoiding long and expensive steps of purification and obtaining informative data on the metabolic composition of the extracts. This study highlights the role of Anabaena as a sustainable and green source of novel bioactive compounds.

Eco-friendly biopesticides derived from CO2-Fixing cyanobacteria

There is currently an escalating global demand for the utilization of plant and natural extracts as pesticides due to their minimal health risks. Cyanobacteria are highly valuable organisms with significant potential in agriculture and are of great interest for the development of agrochemical agents as biopesticides. The flexibility and adaptability of Cyanobacteria to various environmental conditions are facilitated by the presence of specialized enzymes involved in the production of biologically active diverse secondary metabolites, including alkaloids, lipopolysaccharides, non-protein amino acids, non-ribosomal peptides, polyketides, terpenoids, and others. This review focuses on the metabolites synthesized from cyanobacteria that have demonstrated effectiveness as antibacterial, antiviral, antifungal agents, insecticides, herbicides, and more. The potential role of cyanobacteria as an alternative to chemical pesticides for environmental conservation is discussed.

Understanding the Risks of Diffusion of Cyanobacteria Toxins in Rivers, Lakes, and Potable Water

Blue-green algae, or cyanobacteria, may be prevalent in our rivers and tap water. These minuscule bacteria can grow swiftly and form blooms in warm, nutrient-rich water. Toxins produced by cyanobacteria can pollute rivers and streams and harm the liver and nervous system in humans. This review highlights the properties of 25 toxin types produced by 12 different cyanobacteria genera. The review also covered strategies for reducing and controlling cyanobacteria issues. These include using physical or chemical treatments, cutting back on fertilizer input, algal lawn scrubbers, and antagonistic microorganisms for biocontrol. Micro-, nano- and ultrafiltration techniques could be used for the removal of internal and extracellular cyanotoxins, in addition to powdered or granular activated carbon, ozonation, sedimentation, ultraviolet radiation, potassium permanganate, free chlorine, and pre-treatment oxidation techniques. The efficiency of treatment techniques for removing intracellular and extracellular cyanotoxins is also demonstrated. These approaches aim to lessen the risks of cyanobacterial blooms and associated toxins. Effective management of cyanobacteria in water systems depends on early detection and quick action. Cyanobacteria cells and their toxins can be detected using microscopy, molecular methods, chromatography, and spectroscopy. Understanding the causes of blooms and the many ways for their detection and elimination will help the management of this crucial environmental issue.

Insight to biotechnological utility of phycochemicals from cyanobacterium Anabaena sp.: An overview

Cyanobacteria (blue-green algae) are well-known for the ability to excrete extra-cellular products, as a variety of cyanochemicals (phycocompounds) of curio with several extensive therapeutic applications. Among these phycocompound, the cyanotoxins from certain water-bloom forming taxa are toxic to biota, including crocodiles. Failure of current non-renewable source compounds in producing sustainable and non-toxic therapeutics led the urgency of discovering products from natural sources. Particularly, compounds of the filamentous N2-fixing Anabaena sp. have effective antibacterial, antifungal, antioxidant, and anticancer properties. Today, such newer compounds are the potential targets for the possible novel chemical scaffolds, suitable for mainstream-drug development cascades. Bioactive compounds of Anabaena sp. such as, anatoxins, hassallidins and phycobiliproteins have proven their inherent antibacterial, antifungal, and antineoplastic activities, respectively. Herein, the available details of the biomass production and the inherent phyco-constituents namely, alkaloids, lipids, phenols, peptides, proteins, polysaccharides, terpenoids and cyanotoxins are considered, along with geographical distributions and morphological characteristics of the cyanobacterium. The acquisitions of cyanochemicals in recent years have newly addressed several pharmaceutical aliments, and the understanding of the associated molecular interactions of phycochemicals have been considered, for plausible use in drug developments in future.

Halotolerance mechanisms in salt‑tolerant cyanobacteria

Cyanobacteria are ubiquitously distributed in nature and are the most abundant photoautotrophs on Earth. Their long evolutionary history reveals that cyanobacteria have a remarkable capacity and strong adaptive tendencies to thrive in a variety of conditions. Thus, they can survive successfully, especially in harsh environmental conditions such as salty environments, high radiation, or extreme temperatures. Among others, salt stress because of excessive salt accumulation in salty environments, is the most common abiotic stress in nature and hampers agricultural growth and productivity worldwide. These detrimental effects point to the importance of understanding the molecular mechanisms underlying the salt stress response. While it is generally accepted that the stress response mechanism is a complex network, fewer efforts have been made to represent it as a network. Substantial evidence revealed that salt-tolerant cyanobacteria have evolved genomic specific mechanisms and high adaptability in response to environmental changes. For example, extended gene families and/or clusters of genes encoding proteins involved in the adaptation to high salinity have been collectively reported. This chapter focuses on recent advances and provides an overview of the molecular basis of halotolerance mechanisms in salt‑tolerant cyanobacteria as well as multiple regulatory pathways. We elaborate on the major protective mechanisms, molecular mechanisms associated with halotolerance, and the global transcriptional landscape to provide a gateway to uncover gene regulation principles. Both knowledge and omics approaches are utilized in this chapter to decipher the mechanistic insights into halotolerance. Collectively, this chapter would have a profound impact on providing a comprehensive understanding of halotolerance in salt‑tolerant cyanobacteria.

Identification of Cyanobacteria-Based Natural Inhibitors Against SARS-CoV-2 Druggable Target ACE2 Using Molecular Docking Study, ADME and Toxicity Analysis

In 2019-2020, the novel "severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)" had emerged as the biggest challenge for humanity, causing "coronavirus disease 19 (COVID-19)". Scientists around the world have been putting continuous efforts to unfold potential inhibitors of SARS-CoV-2. We have performed computational studies that help us to identify cyanobacterial photoprotective compounds as potential inhibitors against SARS-CoV-2 druggable target human angiotensin-converting enzyme (ACE2), which plays a vital role in the attachment and entry of the virus into the cell. Blocking the receptor-binding domain of ACE2 can prevent the access of the virus into the compartment. A molecular docking study was performed between photoprotective compounds mycosporine-like amino acids, scytonemins and ACE2 protein using AutoDock tools. Among sixteen molecularly docked metabolites, seven compounds were selected with binding energy < 6.8 kcal/mol. Afterwards, drug-likeness and toxicity of the top candidate were predicted using Swiss ADME and Pro Tox-II online servers. All top hits show desirable drug-likeness properties, but toxicity pattern analysis discloses the toxic effect of scytonemin and its derivatives, resulting in the elimination from the screening pipeline. Further molecular interaction study of the rest two ligands, mycosporine-glycine-valine and shinorine with ACE2 was performed using PyMol, Biovia Discovery studio and LigPlot+. Lastly biological activity of both the ligands was predicted by using the PASS online server. Combining the docking score and other studied properties, we believe that mycosporine-glycine-valine and shinorine have potential to be potent inhibitors of ACE2 and can be explored further to use against COVID-19.

Toxicological effects of cyanobacterial metabolites on zebrafish larval development

Freshwater cyanobacteria are known worldwide for their potential to produce toxins. However, these organisms are also found in marine, terrestrial and extreme environments and produce unique compounds, other than toxins. Nevertheless, their effects on biological systems are still barely known. This work tested extracts of different cyanobacterial strains against zebrafish (Danio rerio) larvae and analyzed their metabolomic profiles using liquid chromatography combined with mass spectrometry. Strains Desertifilum tharense, Anagnostidinema amphibium, and Nostoc sp. promoted morphological abnormalities such as pericardial edema, edema in the digestive system region, curvature of the tail and spine in zebrafish larvae in vivo. In contrast, Microcystis aeruginosa and Chlorogloeopsis sp. did not promote such changes. Metabolomics revealed unique compounds belonging to the classes of terpenoids, peptides, and linear lipopeptides/microginins in the nontoxic strains. The toxic strains were shown to contain unique compounds belonging to the classes of cyclic peptides, amino acids and other peptides, anabaenopeptins, lipopeptides, terpenoids, and alkaloids and derivatives. Other unknown compounds were also detected, highlighting the rich structural diversity of secondary metabolites produced by cyanobacteria. The effects of cyanobacterial metabolites on living organisms, mainly those related to potential human and ecotoxicological risks, are still poorly known. This work highlights the diverse, complex, and unique metabolomic profiles of cyanobacteria and the biotechnological potential and associated risks of exposure to their metabolites.

Cyanobacteria as a Valuable Natural Resource for Improved Agriculture, Environment, and Plant Protection

Taking into consideration, the challenges faced by the environment and agro-ecosystem make increased for suggestions more reliable methods to help increase food security and deal with difficult environmental problems. Environmental factors play a critical role in the growth, development, and productivity of crop plants. Unfavorable changes in these factors, such as abiotic stresses, can result in plant growth deficiencies, yield reductions, long-lasting damage, and even death of the plants. In reflection of this, cyanobacteria are now considered important microorganisms that can improve the fertility of soils and the productivity of crop plants due to their different features like photosynthesis, great biomass yield, ability to fix the atmospheric N2, capability to grow on non-arable lands, and varied water sources. Furthermore, numerous cyanobacteria consist of biologically active substances like pigments, amino acids, polysaccharides, phytohormones, and vitamins that support plant growth enhancement. Many studies have exposed the probable role of these compounds in the alleviation of abiotic stress in crop plants and have concluded with evidence of physiological, biochemical, and molecular mechanisms that confirm that cyanobacteria can decrease the stress and induce plant growth. This review discussed the promising effects of cyanobacteria and their possible mode of action to control the growth and development of crop plants as an effective method to overcome different stresses.

Graphical Abstract

Marine Cyanobacterial Peptides in Neuroblastoma: Search for Better Therapeutic Options

Neuroblastoma is the most prevalent extracranial solid tumor in pediatric patients, originating from sympathetic nervous system cells. Metastasis can be observed in approximately 70% of individuals after diagnosis, and the prognosis is poor. The current care methods used, which include surgical removal as well as radio and chemotherapy, are largely unsuccessful, with high mortality and relapse rates. Therefore, attempts have been made to incorporate natural compounds as new alternative treatments. Marine cyanobacteria are a key source of physiologically active metabolites, which have recently received attention owing to their anticancer potential. This review addresses cyanobacterial peptides' anticancer efficacy against neuroblastoma. Numerous prospective studies have been carried out with marine peptides for pharmaceutical development including in research for anticancer potential. Marine peptides possess several advantages over proteins or antibodies, including small size, simple manufacturing, cell membrane crossing capabilities, minimal drug-drug interactions, minimal changes in blood-brain barrier (BBB) integrity, selective targeting, chemical and biological diversities, and effects on liver and kidney functions. We discussed the significance of cyanobacterial peptides in generating cytotoxic effects and their potential to prevent cancer cell proliferation via apoptosis, the activation of caspases, cell cycle arrest, sodium channel blocking, autophagy, and anti-metastasis behavior.

A Multiplex Molecular Cell-Based Sensor to Detect Ligands of PPARs: An Optimized Tool for Drug Discovery in Cyanobacteria

Cyanobacteria produce a wealth of secondary metabolites. Since these organisms attach fatty acids into molecules in unprecedented ways, cyanobacteria can serve as a novel source for bioactive compounds acting as ligands for Peroxisome Proliferator-Activated Receptors (PPAR). PPARs (PPARα, PPARβ/δ and PPARγ) are ligand-activated nuclear receptors, involved in the regulation of various metabolic and cellular processes, thus serving as potential drug targets for a variety of pathologies. Yet, given that PPARs' agonists can have pan-, dual- or isoform-specific action, some controversy has been raised over currently approved drugs and their side effects, highlighting the need for novel molecules. Here, we expand and validate a cell-based PPAR transactivation activity biosensor, and test it in a screening campaign to guide drug discovery. Biosensor upgrades included the use of different reporter genes to increase signal intensity and stability, a different promoter to modulate reporter gene expression, and multiplexing to improve efficiency. Sensor's limit of detection (LOD) ranged from 0.36-0.89 nM in uniplex and 0.89-1.35 nM in multiplex mode. In triplex mode, the sensor's feature screening, a total of 848 fractions of 96 cyanobacteria extracts were screened. Hits were confirmed in multiplex mode and in uniplex mode, yielding one strain detected to have action on PPARα and three strains to have dual action on PPARα and -β.

Process Technologies of Cyanobacteria

Although the handling and exploitation of cyanobacteria is associated with some challenges, these phototrophic bacteria offer great opportunities for innovative biotechnological processes. This chapter covers versatile aspects of working with cyanobacteria, starting with up-to-date in silico and in vitro screening methods for bioactive substances. Subsequently, common conservation techniques and vitality/viability estimation methods are compared and supplemented by own data regarding the non-invasive vitality evaluation via pulse amplitude modulated fluorometry. Moreover, novel findings about the influence the state of the pre-cultures have on main cultures are presented. The following sub-chapters deal with different photobioreactor-designs, with special regard to biofilm photobioreactors, as well as with heterotrophic and mixotrophic cultivation modes. The latter topic provides information from literature on successfully enhanced cyanobacterial production processes, augmented by own data.

Growth and photosynthetic performance of Nostoc linckia (formerly N. calcicola) cells grown in BG11 and BG110 media

The biotechnological potential of Nostoc linckia as a biofertilizer and source of bioactive compounds makes it important to study its growth physiology and productivity. Since nitrogen is a fundamental component of N. linckia biomass, we compared the growth and biochemical composition of cultures grown in BG11 (i.e., in the presence of nitrate) and BG11₀ (in the absence of nitrate). Cultures grown in BG11 accumulated more cell biomass reaching a dry weight of 1.65 ± 0.06 g L^-1, compared to 0.92 ± 0.01 g L^-1 in BG11₀ after 240 h of culture. Biomass productivity was higher in culture grown in BG11 medium (average 317 ± 38 mg L^-1 day^-1) compared to that attained in BG11₀ (average 262 ± 37 mg L^-1 day^-1). The chlorophyll content of cells grown in BG11 increased continuously up to (39.0 ± 1.3 mg L^-1), while in BG11₀ it increased much more slowly (13.6 ± 0.8 mg L^-1). Biomass grown in BG11 had higher protein and phycobilin contents. However, despite the differences in biochemical composition and pigment concentration, between BG11 and BG11₀ cultures, both their net photosynthetic rates and maximum quantum yields of the photosystem II resulted in similar.

Versatile Applications of Cyanobacteria in Biotechnology

Cyanobacteria are blue-green Gram-negative and photosynthetic bacteria which are seen as one of the most morphologically numerous groups of prokaryotes. Because of their ability to fix gaseous nitrogen and carbon dioxide to organic materials, they are known to play important roles in the universal nutrient cycle. Cyanobacteria has emerged as one of the promising resources to combat the issues of global warming, disease outbreaks, nutrition insecurity, energy crises as well as persistent daily human population increases. Cyanobacteria possess significant levels of macro and micronutrient substances which facilitate the versatile popularity to be utilized as human food and protein supplements in many countries such as Asia. Cyanobacteria has been employed as a complementary dietary constituent of feed for poultry and as vitamin and protein supplement in aquatic lives. They are effectively used to deal with numerous tasks in various fields of biotechnology, such as agricultural (including aquaculture), industrial (food and dairy products), environmental (pollution control), biofuel (bioenergy) and pharmaceutical biotechnology (such as antimicrobial, anti-inflammatory, immunosuppressant, anticoagulant and antitumor); recently, the growing interest of applying them as biocatalysts has been observed as well. Cyanobacteria are known to generate a numerous variety of bioactive compounds. However, the versatile potential applications of cyanobacteria in biotechnology could be their significant growth rate and survival in severe environmental conditions due to their distinct and unique metabolic pathways as well as active defensive mechanisms. In this review, we elaborated on the versatile cyanobacteria applications in different areas of biotechnology. We also emphasized the factors that could impede the implementation to cyanobacteria applications in biotechnology and the execution of strategies to enhance their effective applications.

Therapeutic Efficacy of Natural Product 'C-Phycocyanin' in Alleviating Streptozotocin-Induced Diabetes via the Inhibition of Glycation Reaction in Rats

Diabetes is a long-term metabolic disorder characterized by persistently elevated blood sugar levels. Chronic hyperglycemia enhances glucose-protein interactions, leading to the formation of advanced glycation end products (AGEs), which form irreversible cross-links with a wide variety of macromolecules, and accumulate rapidly in the body tissues. Thus, the objective of this study was to assess the therapeutic properties of C-phycocyanin (C-PC) obtained from Plectonema species against oxidative stress, glycation, and type 2 diabetes mellitus (T2DM) in a streptozotocin (STZ)-induced diabetic Wistar rat. Forty-five days of C-PC administration decreased levels of triglycerides (TGs), blood glucose, glycosylated hemoglobin, (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), liver and kidney function indices, and raised body weight in diabetic rats. C-PC suppressed biochemical glycation markers, as well as serum carboxymethyllysine (CML) and fluorescent AGEs. Additionally, C-PC maintained the redox state by lowering lipid peroxidation and protein-bound carbonyl content (CC), enhancing the activity of high-density lipoprotein cholesterol (HDL-C) and renal antioxidant enzymes, and preserving retinal and renal histopathological characteristics. Thus, we infer that C-PC possesses antidiabetic and antiglycation effects in diabetic rats. C-PC may also act as an antidiabetic and antiglycation agent in vivo that may reduce the risk of secondary diabetic complications.

Uses and benefits of algae as a nutritional supplement for honey bees

Honey bees are essential agricultural pollinators that are threatened by various interacting stressors, posing risks to beekeeping industries and human food security. Malnutrition is a major factor underlying managed bee colony losses that can be countered by feeding artificial diets, which aim to deliver essential macro- and micronutrients. Current bee nutritional supplements show room for improvement and require resources that compete with human food production. Algae and microalgae in particular have been gaining traction in the literature as alternative feed sources and nutritional supplements for livestock, including honey bees. Herein, we review the current literature and categorize the effects of algae supplementation on honey bee colony productivity as well as effects on individual bee physiology and health. In general, we conclude that algae biomass appears to be suitable for use as a bee feed additive and as a source of health-stimulating natural products. Additionally, we suggest research areas that could improve the development of sustainable algae-based nutrition supplements for honey bees.

Role of Antioxidant Enzymes and Glutathione S-Transferase in Bromoxynil Herbicide Stress Tolerance in Wheat Plants

BACKGROUND

Numerous pesticides and herbicides used in excess cause oxidative stress in plants. These chemicals protect plants from weeds and pests, but they also have very negative side effects, making them common abiotic stressors. One of the most significant nutritional crops in the world is the wheat plant. Conditions of herbicide stress have a negative impact on the plant's phonological phases and metabolic pathways. Plants primarily make an effort to adjust to the environment and develop oxidative homeostasis, which supports stress tolerance.

METHODS

When controlling broadleaf weeds that emerge after cereal crop plants have been planted, bromoxynil is frequently used as a selective-contact herbicide. This study looked at the effects of the cyanobacteria Arthrospira platensis and Nostoc muscorum aqueous extracts, tryptophan, and bromoxynil (Bh) alone or in combination on wheat plant growth parameters. Both tryptophan and cyanobacterial extract were used as chemical and natural safeners against Bh application. The antioxidant activity and transcriptome studies using qRT-PCR were assayed after 24, 48, 72, 96 h, and 15 days from Bh application in the vegetation stage of wheat plants (55 days old).

RESULTS

In comparison with plants treated with Bh, wheat plants treated with cyanobacteria and tryptophan showed improvements in all growth parameters. Following application of Bh, wheat plants showed reduced glutathione content, as well as reduced antioxidant enzyme activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione-s-transferase. The combination of different treatments and Bh caused alleviation of the harmful effect induced by Bh on the measured parameters. Additionally, the expression of glutathione synthase and glutathione peroxidase, in addition to those of three genes (Zeta, Tau, and Lambda) of the GST gene family, was significantly upregulated when using Bh alone or in combination with different treatments, particularly after 24 h of treatment.

CONCLUSION

The current study suggests using cyanobacterial extracts, particularly the A. platensis extract, for the development of an antioxidant defense system against herbicide toxicity, which would improve the metabolic response of developed wheat plants.

Synthesis of the cyanobacterial halometabolite Chlorosphaerolactylate B and demonstration of its antimicrobial effect in vitro and in vivo

Chlorosphaerolactylate B, a newly discovered antimicrobial halometabolite from the cyanobacterium Sphaerospermopsis sp. LEGE 00249 has been synthesized in three steps by using 12-bromododecanoic acid as starting material. A total of 0.5 g was produced for in vitro and in vivo antimicrobial efficacy testing. In vitro, the minimal inhibitory concentration (MIC) was estimated to be 256 mg/L for Staphylococcus aureus, while the minimal biofilm inhibitory concentration (MBIC) was estimated to be 74 mg/L. The in vivo study utilized a porcine model of implant-associated osteomyelitis. In total, 12 female pigs were allocated into 3 groups based on inoculum (n = 4 in each group). An implant cavity (IC) was drilled in the right tibia and followed by inoculation and insertion of a steel implant. All pigs were inoculated with 10 μL containing either: 11.79 mg synthetic Chlorosphaerolactylate B + 10⁴ CFU of S. aureus (Group A), 10⁴ CFU of S. aureus (Group B), or pure saline (Group C), respectively. Pigs were euthanized five days after inoculation. All Group B animals showed macroscopic and microscopic signs of bone infection and both tissue and implant harbored S. aureus bacteria (mean CFU on implants = 1.9 × 10⁵). In contrast, S. aureus could not be isolated from animals inoculated with saline. In Group A, two animals had a low number of S. aureus (CFU = 6.7 × 10¹ and 3.8 × 10¹, respectively) on the implants, otherwise all Group A animals were similar to Group C animals. In conclusion, synthetic Chlorosphaerolactylate B holds potential to be a novel antimicrobial and antibiofilm compound.

Anti-lung cancer properties of cyanobacterial bioactive compounds

Lung cancer, the most prevalent gender-independent tumor entity in both men and women, is among the leading cause of cancer-related deaths worldwide. Despite decades of effort in developing improved therapeutic strategies including immunotherapies and novel chemotherapeutic agents, only modest improvements in outcome and long-term survival of lung cancer patients have been achieved. Therefore, exploring new and exceptional sources for bioactive compounds that might serve as anti-cancer agents might be the key to improving lung cancer therapy. On account of diverse forms, cyanobacteria might serve as a potential source for compounds with potential therapeutic applicability against malignant disorders, including cancer. The assorted arrays of metabolic mechanisms synthesize a plethora of bioactive compounds with immense biological potential. These compounds have been proven to be effective against various cancer cell lines and xenograft animal models. The present review provides an overview of the most promising cyanobacteria-derived bioactive compounds proven to exhibit anti-cancer properties in in-vitro and in-vivo studies and highlights their applicability as potential therapeutic agents with a focus on their anti-lung cancer properties.

Bioprospecting microalgae and cyanobacteria for biopharmaceutical applications

Microalgae and cyanobacteria have sparked a lot of interest due to their potential in various industries like biorefineries, biopharmaceuticals, food supplements, nutraceuticals, and other high-value products. Polysaccharides, vitamins, proteins, enzymes, and steroids are valuable products isolated from microalgae and cyanobacteria and potentially used in health and biomedical applications. Bioactive compounds derived from microalgae and cyanobacteria exhibit various pharmaceutical properties like antibacterial, anticancer, antiviral, antialgal, and antioxidant. From the properties listed above, the research for novel antibiotics has become particularly appropriate. In addition, the possible emergence of resistance against pathogens, as well as the potential decline in antibiotic efficacy, has prompted researchers to look for a new source of antibiotics. Microalgae and cyanobacteria have indicated a great and unexplored potential among these sources. For this reason, microalgae and cyanobacteria have been highlighted for their efficiency in different industrial sectors, as well as for their potential uses in the betterment of human and environmental health. This review gives an overview of bioactive compounds and metabolites with several biological properties isolated from microalgae and cyanobacteria for treating different animal and human diseases.

Effects of harvesting on morphological and biochemical characteristics of microalgal biomass harvested by polyacrylamide addition, pH-induced flocculation, and centrifugation

The effects of microalgae harvesting methods on microalgal biomass quality were evaluated using three species namely the freshwater green alga Chlorella vulgaris, marine red alga Porphyridium purpureum and marine diatom Phaeodactylum tricornutum. Harvesting efficiencies of polyacrylamide addition, alkaline addition, and centrifugation ranged from 85 to 95, 59-92 and 100%, respectively, across these species. Morphology of the harvested cells (i.e. compromised cell walls) was significantly impacted by alkaline pH-induced flocculation for all three species. Over 50% of C. vulgaris cells were compromised with alkaline pH compared to < 10% with polyacrylamide and centrifugation. The metabolic profiles varied depending on harvesting methods. Species-specific decrease of certain metabolites was observed. These results suggest that the method of harvest can alter the metabolic profile of the biomass amongst the three harvesting methods, polyacrylamide addition showed higher harvesting efficiency with less compromised cells and higher retention of industry important biochemicals.

Nutrient management and medium reuse for cultivation of a cyanobacterial consortium at high pH and alkalinity

Alkaliphilic cyanobacteria have gained significant interest due to their robustness, high productivity, and ability to convert CO2 into bioenergy and other high value products. Effective nutrient management, such as re-use of spent medium, will be essential to realize sustainable applications with minimal environmental impacts. In this study, we determined the solubility and uptake of nutrients by an alkaliphilic cyanobacterial consortium grown at high pH and alkalinity. Except for Mg, Ca, Co, and Fe, all nutrients are in fully soluble form. The cyanobacterial consortium grew well without any inhibition and an overall productivity of 0.15 g L−1 d−1 (AFDW) was achieved. Quantification of nutrient uptake during growth resulted in the empirical formula CH1.81N0.17O0.20P0.013S0.009 for the consortium biomass. We showed that spent medium can be reused for at least five growth/harvest cycles. After an adaptation period, the cyanobacterial consortium fully acclimatized to the spent medium, resulting in complete restoration of biomass productivity.

Media engineering in marine diatom Phaeodactylum tricornutum employing cost-effective substrates for sustainable production of high-value renewables

Phaeodactylum tricornutum is a marine diatom, rich in omega-3 polyunsaturated fatty acids especially eicosapentaenoic acid (EPA) and brown pigment, that is, fucoxanthin. These high-value renewables (HVRs) have a high commercial and nutritional relevance. In this study, our focus was to enhance the productivities of such renewables by employing media engineering strategy via., photoautotrophic (P1, P2, P3) and mixotrophic (M1, M2, M3, M4) modes of cultivation with varying substrate combinations of carbon (glycerol: 0.1 m) and nitrogen (urea: 441 mm and/or sodium nitrate: 882 mm). Our results demonstrate that mixotrophic [M4] condition supplemented with glycerol (0.1 m) and urea (441 mm) feed enhanced productivities (mg L^-1  day^-1 ) as follows: biomass (770.0), total proteins (36.0), total lipids (22.0), total carbohydrates (23.0) with fatty acid methyl esters (9.6), EPA (2.7), and fucoxanthin (1.1), respectively. The overall yield of EPA represents 28% of total fatty acids in the mixotrophic [M4] condition. In conclusion, our improved strategy of feeding urea to a glycerol-supplemented medium defines a new efficient biomass valorization paradigm with cost-effective substrates for the production of HVRs in oleaginous diatoms P. tricornutum.

Anti-Inflammatory Extract from Soil Algae Chromochloris zofingiensis Targeting TNFR/NF-κB Signaling at Different Levels

Inflammatory skin diseases, including atopic dermatitis (AD) and psoriasis, are increasing in populations worldwide. The treatment of patients with AD and other forms of skin inflammation is mainly based on the use of topical corticosteroids or calcineurin inhibitors, which can cause significant side effects with long-term use. Therefore, there is a great need for the development of more effective and less toxic anti-inflammatory agents suitable for the treatment of chronic skin lesions. Here, we screened a number of strains from the ASIB 505 terrestrial algae collection and identified a green algae Chromochloris zofingiensis with pronounced anti-inflammatory properties. We found that a crude nonpolar extract of C. zofingiensis (ID name NAE_2022C), grown upon nitrogen deprivation, acts as a bioactive substance by inhibiting TNFR/NF-κB responses in human skin keratinocyte HaCaT cells. We also found that NAE_2022C suppressed the secretion of pro-inflammatory cytokine tumor necrosis factor α (TNFα) and several Th1- and Th2-related chemokines in a reconstituted human epidermis. The TNFR/NF-κB pathway analysis showed multiple inhibitory effects at different levels and disclosed a direct targeting of IKKβ by the extract. Bioassay-guided fractionation followed by high-resolution mass spectrometry detected diacylglyceryl-trimethylhomoserine (DGTS), Lyso-DGTS (LDGTS), 5-phenylvaleric acid, theophylline and oleamide as leading metabolites in the active fraction of NAE_2022C. Further analysis identified betaine lipid DGTS (32:0) as one of the active compounds responsible for the NAE_2022C-mediated NF-κB suppression. Overall, this study presents an approach for the isolation, screening, and identification of anti-inflammatory secondary metabolites produced by soil algae.

A checklist of blue-green algae (Cyanobacteria) from Punjab, India

A checklist of Cyanobacteria (Blue-green algae) has been made by reviewing available literature in order to contribute to the knowledge of biodiversity of algae in the Punjab state of India. The list records 317 taxa of the phylum Cyanobacteria distributed among 74 genera, 32 families, and six orders. The order Oscillatoriales has 115 taxa, followed by Nostocales (84), Synechococcales (60), Chroococcales (49), Spirulinales (8), and Pleurocapsales (1). The family Nostocaceae has the maximum number of genera followed by Microcoleaceae, Chroococcaceae, Oscillatoriaceae and other reported families. The genera with the highest number of species were Phormidium (39 species), Lyngbya (15 species), Oscillatoria (14 species), and Leptolyngbya & Scytonema (13 species each). The checklist revealed a high degree of species richness within phylum Cyanobacteria found in Punjab. This checklist can provide a baseline for future floristic studies with taxonomically updated/accepted name of genera/species of cyanobacteria.

Cyanobacterial biorefinery: Towards economic feasibility through the maximum valorization of biomass

Cyanobacteria are well known for their plethora of applications in the fields of food industry, pharmaceuticals and bioenergy. Their simple growth requirements, remarkable growth rate and the ability to produce a wide range of bio-active compounds enable them to act as an efficient biorefinery for the production of valuable metabolites. Most of the cyanobacteria based biorefineries are targeting single products and thus fails to meet the efficient valorization of biomass. On the other hand, multiple products recovering cyanobacterial biorefineries can efficiently valorize the biomass with minimum to zero waste generation. But there are plenty of bottlenecks and challenges allied with cyanobacterial biorefineries. Most of them are being associated with the production processes and downstream strategies, which are difficult to manage economically. There is a need to propose new solutions to eliminate these tailbacks so on to elevate the cyanobacterial biorefinery to be an economically feasible, minimum waste generating multiproduct biorefinery. Cost-effective approaches implemented from production to downstream processing without affecting the quality of products will be beneficial for attaining economic viability. The integrated approaches in cultivation systems as well as downstream processing, by simplifying individual processes to unit operation systems can obviously increase the economic feasibility to a certain extent. Low cost approaches for biomass production, multiparameter optimization and successive sequential retrieval of multiple value-added products according to their high to low market value from a biorefinery is possible. The nanotechnological approaches in cyanobacterial biorefineries make it one step closer to the goal. The current review gives an overview of strategies used for constructing self-sustainable- economically feasible- minimum waste generating; multiple products based cyanobacterial biorefineries by the efficient valorization of biomass. Also the possibility of uplifting new cyanobacterial strains for biorefineries is discussed.

Microalgal drugs: A promising therapeutic reserve for the future

Over the decades, a variety of chemically synthesized drugs are being used to cure existing diseases but often these drugs could not be effectively employed for the treatment of serious and newly emerging diseases. Fortunately, in nature there occurs immense treasure of plants and microorganisms which are living jewels with respect to their richness of medically important metabolites of high value. Hence, amongst the existing microorganism(s), the marine world offers a plethora of biological entities that can contribute to alleviate numerous human ailments. Algae are one such photosynthetic microorganism found in both marine as well as fresh water which are rich source of metabolites known for their nutrient content and health benefits. Various algal species like Haematococcus, Diatoms, Griffithsia, Chlorella, Spirulina, Ulva, etc. have been identified and isolated to produce biologically active and pharmaceutically important high value compounds like astaxanthin, fucoxanthin, sulphur polysaccharides mainly galactose, rhamnose, xylose, fucose etc., which show antimicrobial, antifungal, anti-cancer, and antiviral activities. However, the production of either of these bio compounds is favored under conditions of stress. This review gives detailed information on various nutraceutical metabolites extracted from algae. Additionally focus has been made on the role of these bio compounds extracted from algae especially sulphur polysaccharides to treat several diseases with prospective treatment for SARS-CoV-2. Lastly it covers the knowledge gaps and future perspectives in this area of research.

Algae: Study of Edible and Biologically Active Fractions, Their Properties and Applications

The beneficial properties of algae make them perfect functional ingredients for food products. Algae have a high energy value and are a source of biologically active substances, proteins, fats, carbohydrates, vitamins, and macro- and microelements. They are also rich in polyunsaturated fatty acids, proteins, mycosporine-like amino acids, polysaccharides, polyphenols, carotenoids, sterols, steroids, lectins, halogenated compounds, polyketides, alkaloids, and carrageenans. Different extraction parameters are used depending on the purpose and the substances to be isolated. In this study, the following parameters were used: hydromodule 1:10 and an extraction duration of 1-2 h at the extraction temperature of 25-40 °C. A 30-50% solution of ethanol in water was used as an extractant. Algae extracts can be considered as potential natural sources of biologically active compounds with antimicrobial activity and antiviral properties. The content of crude protein, crude fat, and carbohydrates in U. Prolifera, C. racemosa var. peltata (Chlorophyta), S. oligocystum and S. fusiforme (SF-1) was studied. It was found that C. muelleri (Bacillariophyta), I. galbana (Haptophyta), and T. weissflogii (Bacillariophyta) contain about 1.9 times more omega-3 than omega-6 fatty acids. N. gaditana (Ochrophyta), D. salina (Chlorophyta), P. tricornutum (Bacillaryophyta) and I. galbana (Haptophyta) extracts showed inhibitory activity of varying intensities against E. coli or P. aeruginosa. In addition, algae and algae-derived compounds have been proposed to offer attractive possibilities in the food industry, especially in the meat sector, to evolve functional foods with myriad functionalities. Algae can increase the biological activity of food products, while the further study of the structure of compounds found in algae can broaden their future application possibilities.

Inhibition of Filamentous Thermosensitive Mutant-Z Protein in Bacillus subtilis by Cyanobacterial Bioactive Compounds

Antibiotic resistance is one of the major growing concerns for public health. Conventional antibiotics act on a few predefined targets and, with time, several bacteria have developed resistance against a large number of antibiotics. The WHO has suggested that antibiotic resistance is at a crisis stage and identification of new antibiotics and targets could be the only approach to bridge the gap. Filamentous Temperature Sensitive-Mutant Z (Fts-Z) is one of the promising and less explored antibiotic targets. It is a highly conserved protein and plays a key role in bacterial cell division by introducing a cytokinetic Z-ring formation. In the present article, the potential of over 165 cyanobacterial compounds with reported antibiotic activity against the catalytic core domain in the Fts-Z protein of the Bacillus subtilis was studied. The identified cyanobacterial compounds were screened using the GLIDE module of Maestro v-2019-2 followed by 100-ns molecular dynamics (MD) simulation. Ranking of the potential compound was performed using dock score and MMGBSA based free energy. The study reported that the docking score of aphanorphine (−6.010 Kcalmol⁻¹) and alpha-dimorphecolic acid (ADMA) (−6.574 Kcalmol⁻¹) showed significant role with respect to the reported potential inhibitor PC190723 (−4.135 Kcalmol⁻¹). A 100 ns MD simulation infers that Fts-Z ADMA complex has a stable conformation throughout the progress of the simulation. Both the compounds, i.e., ADMA and Aphanorphine, were further considered for In-vitro validation by performing anti-bacterial studies against B. subtilis by agar well diffusion method. The results obtained through In-vitro studies confirm that ADMA, a small molecule of cyanobacterial origin, is a potential compound with an antibacterial activity that may act by inhibiting the novel target Fts-Z and could be a great drug candidate for antibiotic development.

Algal Metabolites Can Be an Immune Booster against COVID-19 Pandemic

The world has faced the challenges of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) for the last two years, first diagnosed at the end of 2019 in Wuhan and widely distributed worldwide. As a result, the WHO has proclaimed the illness brought on by this virus to be a global pandemic. To combat COVID-19, researcher communities continuously develop and implement rapid diagnoses, safe and effective vaccinations and other alternative therapeutic procedures. However, synthetic drug-related side effects and high costs have piqued scientists’ interest in natural product-based therapies and medicines. In this regard, antiviral substances derived from natural resources and some medicines have seen a boom in popularity. For instance, algae are a rich source of compounds such as lectins and sulfated polysaccharides, which have potent antiviral and immunity-boosting properties. Moreover, Algae-derived compounds or metabolites can be used as antibodies and vaccine raw materials against COVID-19. Furthermore, some algal species can boost immunity, reduce viral activity in humans and be recommended for usage as a COVID-19 preventative measure. However, this field of study is still in its early stages of development. Therefore, this review addresses critical characteristics of algal metabolites, their antioxidant potential and therapeutic potential in COVID-19.

Untargeted metabolomics of the alkaliphilic cyanobacterium Plectonema terebrans elucidated novel stress-responsive metabolic modulations

Alkaliphilic cyanobacteria are suitable candidates to study the effect of alkaline wastewater cultivation on molecular metabolic responses. In the present study, the impact of wastewater, alkalinity, and alkaline wastewater cultivation was studied on the biomass production, biochemical composition, and the alkalinity responsive molecular mechanism through metabolomics. The results suggested a 1.29 to 1.44-fold higher biomass production along with improved lipid, carbohydrate, and pigment production under alkaline wastewater cultivation. The metabolomics analysis showed 1.2-fold and 5.54-fold increase in the indole-acetic acid and phytoene biosynthesis which contributed to overall enhanced cell differentiation and photo-protectiveness. Furthermore, lower levels of Ribulose-1,5-bisphosphate (RuBP), and higher levels of 2-phosphoglycerate and 3-phosphoglycerate suggested the efficient fixation of CO₂ into biomass, and storage compounds including polysaccharides, lipids, and sterols. Interestingly, except L-histidine and L-phenylalanine, all the metabolites related to protein biosynthesis were downregulated in response to wastewater and alkaline wastewater cultivation. The cells protected themselves from alkalinity and nutrient stress by improving the biosynthesis of sterols, non-toxic antioxidants, and osmo-protectants. Alkaline wastewater cultivation regulated the activation of carbon concentration mechanism (CCM), glycolysis, fatty-acid biosynthesis, and shikimate pathway. The data revealed the importance of alkaline wastewater cultivation for improved CO₂ fixation, wastewater treatment, and producing valuable bioproducts including phytoene, Lyso PC 18:0, and sterols. These metabolic pathways could be future targets of metabolic engineering for improving biomass and metabolite production. SIGNIFICANCE: Alkalinity is an imperative factor, responsible for the contamination control and biochemical regulation in cyanobactera, especially during the wastewater cultivation. Currently, understanding of alkaline wastewater responsive molecular mechanism is lacking and most of the studies are focused on transcriptomics of model organisms for this purpose. In this study, untargeted metabolomics was employed to analyze the impact of wastewater and alkaline wastewater on the growth, CO₂ assimilation, nutrient uptake, and associated metabolic modulations of the alkaliphilic cyanobacterium Plectonema terebrans BERC10. Results unveiled that alkaline wastewater cultivation regulated the activation of carbon concentration mechanism (CCM), glycolysis, fatty-acid biosynthesis, and shikimate pathway. It indicated the feasibility of alkaline wastewater as promising low-cost media for cyanobacterium cultivation. The identified stress-responsive pathways could be future genetic targets for strain improvement.

Algae and Their Metabolites as Potential Bio-Pesticides

An increasing human population necessitates more food production, yet current techniques in agriculture, such as chemical pesticide use, have negative impacts on the ecosystems and strong public opposition. Alternatives to synthetic pesticides should be safe for humans, the environment, and be sustainable. Extremely diverse ecological niches and millions of years of competition have shaped the genomes of algae to produce a myriad of substances that may serve humans in various biotechnological areas. Among the thousands of described algal species, only a small number have been investigated for valuable metabolites, yet these revealed the potential of algal metabolites as bio-pesticides. This review focuses on macroalgae and microalgae (including cyanobacteria) and their extracts or purified compounds, that have proven to be effective antibacterial, antiviral, antifungal, nematocides, insecticides, herbicides, and plant growth stimulants. Moreover, the mechanisms of action of the majority of these metabolites against plant pests are thoroughly discussed. The available information demonstrated herbicidal activities via inhibition of photosynthesis, antimicrobial activities via induction of plant defense responses, inhibition of quorum sensing and blocking virus entry, and insecticidal activities via neurotoxicity. The discovery of antimetabolites also seems to hold great potential as one recent example showed antimicrobial and herbicidal properties. Algae, especially microalgae, represent a vast untapped resource for discovering novel and safe biopesticide compounds.

Phycochemistry and bioactivity of cyanobacterial secondary metabolites

Microbes are a huge contributor to people's health around the world since they produce a lot of beneficial secondary metabolites. Cyanobacteria are photosynthetic prokaryotic bacteria cosmopolitan in nature. Adaptability of cyanobacteria to wide spectrum of environment can be contributed to the production of various secondary metabolites which are also therapeutic in nature. As a result, they are a good option for the development of medicinal molecules. These metabolites could be interesting COVID-19 therapeutic options because the majority of these compounds have demonstrated substantial pharmacological actions, such as neurotoxicity, cytotoxicity, and antiviral activity against HCMV, HSV-1, HHV-6, and HIV-1. They have been reported to produce a single metabolite active against wide spectrum of microbes like Fischerella ambigua produces ambigols active against bacteria, fungi and protozoa. Similarly, Moorea producens produces malygomides O and P, majusculamide C and somocystinamide which are active against bacteria, fungi and tumour cells, respectively. In addition to the above, Moorea sp. produce apratoxin A and dolastatin 15 possessing anti cancerous activity but unfortunately till date only brentuximab vedotin (trade name Adcetris), a medication derived from marine peptides, for the treatment of Hodgkin lymphoma and anaplastic large cell lymphoma has been approved by FDA. However, several publications have effectively described and categorised cyanobacterial medicines based on their biological action. In present review, an effort is made to categorize cyanobacterial metabolites on the basis of their phycochemistry. The goal of this review is to categorise cyanobacterial metabolites based on their chemical functional group, which has yet to be described.

Gut Microbiota-Medication Interaction in Rheumatic Diseases

Besides its contribution to the development of rheumatic diseases, the gut microbiota interact with anti-rheumatic drugs. The intestinal microbiota can directly metabolize many drugs and indirectly change drug metabolism through a complex multi-dimensional interaction with the host, thus affecting individual response to drug therapy and adverse effects. The focus of the current review is to address recent advances and important progress in our understanding of how the gut microbiota interact with anti-rheumatic drugs and provide perspectives on promoting precision treatment, drug discovery, and better therapy for rheumatic diseases.

Cyanobacteria derived compounds: Emerging drugs for cancer management

The wide diversity of cyanobacterial species and their role in a variety of biological activities have been reported in the previous few years. Cyanobacteria, especially from marine sources, constitutes a major source of biologically active metabolites that have gained great attention especially due to their anticancer potential. Numerous chemically diverse metabolites from various cyanobacterial species have been recognized to inhibit the growth and progression of tumor cells through the induction of apoptosis in many different types of cancers. These metabolites activate the apoptosis in the cancer cells by different molecular mechanisms, however, the dysregulation of the mitochondrial pathway, death receptors signaling pathways, and the activation of several caspases are the crucial mechanisms that got considerable interest. The array of metabolites and the range of mechanisms involved may also help to overcome the resistance acquired by the different tumor types against the ongoing therapeutic agents. Therefore, the primary or secondary metabolites from the cyanobacteria as well as their synthetic derivates could be used to develop novel anticancer drugs alone or in combination with other chemotherapeutic agents. In this study, we have discussed the role of cyanobacterial metabolites in the induction of cytotoxicity and the potential to inhibit the growth of cancer cells through the induction of apoptosis, cell signaling alteration, oxidative damage, and mitochondrial dysfunctions. Moreover, the various metabolites produced by cyanobacteria have been summarized with their anticancer mechanisms. Furthermore, the ongoing trials and future developments for the therapeutic implications of these compounds in cancer therapy have been discussed.

Dynamics of the Metabolome of Aliinostoc sp. PMC 882.14 in Response to Light and Temperature Variations

Cyanobacteria are microorganisms able to adapt to a wide variety of environmental conditions and abiotic stresses. They produce a large number of metabolites that can participate in the dynamic adaptation of cyanobacteria to a range of different light, temperature, and nutrient conditions. Studying the metabolite profile is one way to understand how the physiological status of cells is related to their adaptive response. In this study, we sought to understand how the diversity and dynamics of the whole metabolome depended on the growth phase and various abiotic factors such as light intensity and temperature. The cyanobacterium, Aliinostoc sp. PMC 882.14, was selected for its large number of biosynthetic gene clusters. One group of cells was grown under normal conditions as a control, while other groups were grown under higher light or temperature. Metabolomes were analyzed by mass spectrometry (qTOF-MS/MS) combined with untargeted analysis to investigate metabolite dynamics, and significant variation was found between exponential and stationary phases, regardless of culture conditions. In the higher light group, the synthesis of several metabolites, including shinorine, was induced while other metabolites, such as microviridins, were synthesized under higher temperature conditions. Among highly regulated metabolites, we observed the presence of mycosporine-like amino acids (MAAs) and variants of somamides, microginins, and microviridins. This study demonstrated the importance of considering the physiological state of cyanobacteria for comparative global metabolomics and studies of the regulatory processes involved in production of specific metabolites. Our results also open up new perspectives on the use of organisms such as cyanobacteria for the targeted production of bioactive metabolites.

Potential of Producing Flavonoids Using Cyanobacteria As a Sustainable Chassis

Numerous plant secondary metabolites have remarkable impacts on both food supplements and pharmaceuticals for human health improvement. However, higher plants can only generate small amounts of these chemicals with specific temporal and spatial arrangements, which are unable to satisfy the expanding market demands. Cyanobacteria can directly utilize CO₂, light energy, and inorganic nutrients to synthesize versatile plant-specific photosynthetic intermediates and organic compounds in large-scale photobioreactors with outstanding economic merit. Thus, they have been rapidly developed as a "green" chassis for the synthesis of bioproducts. Flavonoids, chemical compounds based on aromatic amino acids, are considered to be indispensable components in a variety of nutraceutical, pharmaceutical, and cosmetic applications. In contrast to heterotrophic metabolic engineering pioneers, such as yeast and Escherichia coli, information about the biosynthesis flavonoids and their derivatives is less comprehensive than that of their photosynthetic counterparts. Here, we review both benefits and challenges to promote cyanobacterial cell factories for flavonoid biosynthesis. With increasing concerns about global environmental issues and food security, we are confident that energy self-supporting cyanobacteria will attract increasing attention for the generation of different kinds of bioproducts. We hope that the work presented here will serve as an index and encourage more scientists to join in the relevant research area.

Cotton bandages finished with microcapsules of volatile organic constituents of marine macro-algae for wound healing

Microencapsulation is an innovative technique having a growing application in textile finishing. Besides, marine macroalgae contain plenty of phytoconstituents used in various fields especially textile finishing. This work imparts the property of wound healing finish to cotton fabrics producing a bandage from eco-friendly algal volatile organic constituents (VOCs). VOCs extracted from Digenea simplex, Lurencea papillosa, Galaxurea oblongata, and Turbenaria decurrens Egyptian marine macroalgae scattered along the coastline of the Red sea were 0.52, 0.9, 0.87, and 0.62% (v/w), respectively. These VOCs as well as their microencapsulated (VOM) forms were finished onto cotton fabrics by a conventional pad-dry cure technique using sodium alginate (SA) as a shell wall material. The VOCs of each alga were extracted and chemically investigated using gas chromatography coupled with mass spectrometry (GC-MS). The results indicate, in addition to the identification of 125 volatile compounds, the diversity and outstanding differences in volatile composition among the 4 algae. Wound healing activities of the finished fabrics were evaluated. VOCs microcapsules-finished (VOMF) fabrics were more effective compared to VOCs-finished (VOF) fabrics and almost comparable to mebo-ointment (standard drug)-finished (MoF) fabrics. The differences in VOCs efficiencies may be attributable to the diversity in type and amount of volatiles found in the four algae. Therefore, this is a low-cost, convenient, reproducible, and scalable way to obtain encapsulated VOCs for the application in textile wound healing.

Plant Tolerance to Drought Stress in the Presence of Supporting Bacteria and Fungi: An Efficient Strategy in Horticulture

Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed different strategies to cope with stress by morphological, physiological, anatomical, and biochemical responses. First, visible changes influence plant biomass and consequently limit the yield of crops. The presented review was undertaken to discuss the impact of climate change with respect to drought stress and its impact on the performance of plants inoculated with plant growth-promoting microorganisms (PGPM). The main challenge for optimal performance of horticultural plants is the application of selected, beneficial microorganisms which actively support plants during drought stress. The most frequently described biochemical mechanisms for plant protection against drought by microorganisms are the production of phytohormones, antioxidants and xeroprotectants, and the induction of plant resistance. Rhizospheric or plant surface-colonizing (rhizoplane) and interior (endophytic) bacteria and fungi appear to be a suitable alternative for drought-stress management. Application of various biopreparations containing PGPM seems to provide hope for a relatively cheap, easy to apply and efficient way of alleviating drought stress in plants, with implications in productivity and food condition.

Anti-leishmanial compounds from microbial metabolites: a promising source

Leishmania is a complex disease caused by the protozoan parasites and transmitted by female phlebotomine sandfly. The disease affects some of the poorest people on earth with an estimated 700,000 to 1 million new cases annually. The current treatment for leishmaniasis is toxic, long, and limited, in view of the high resistance rate presented by the parasite, necessitating new perspectives for treatment. The discovery of new compounds with different targets can be a hope to make the treatment more efficient. Microbial metabolites and their structural analogues with enormous scaffold diversity and structural complexity have historically played a key role in drug discovery. We found thirty-nine research articles published between 1999 and 2021 in the scientific database (PubMed, Science Direct) describing microbes and their metabolites with activity against leishmanial parasites which is the focus of this review. KEY POINTS: • Leishmania affects the poorest regions of the globe • Current treatments for leishmaniasis are toxic and of limited efficacy • Microbial metabolites are potential sources of antileishmania drugs.

Screening and isolation of microbes from a Mud Community of Ischia Island Thermal Springs: preliminary analysis of a bioactive compound

Introduction

Balneotherapy centers of Ischia island (Italy) offer treatments for different dermatological diseases (psoriasis, acne, atopic dermatitis) and upper respiratory tract infections. In this study, we integrated morphological and molecular approaches to give a focus on isolation and screening of extremophile bacteria from Ischia thermal mud for potential antimicrobial applications.

Methods

Samples were collected during 2019 at four sites. Some bacterial strains ATCC for antibacterial and antibiofilm activity were tested. After morphological characterization, screening for antagonistic isolates was made. The colonies isolated from thermal mud samples were submitted to molecular characterization. Susceptibility testing by dilution spotting was carried out and antibacterial efficacies of most active isolate were evaluated with a Minimal inhibition concentration assay. Biofilm formation, inhibition, eradication were examined. Statistical analyses were carried out utilizing Microsoft^® Excel 2016/XLSTAT^©-Pro.

Results

We isolated a natural compound with antimicrobial and antibiofilm activities.

Conclusions

The results obtained in this study are discussed in the context of how hydrothermal systems are important environmental source of uncharted antimicrobial and antibiofilm compounds. In conclusion, to the most effective of our knowledge, this work presents the primary report on the preliminary investigation of thermophile microbial diversity and their antimicrobial and antibiofilm activities for future biotechnological interest.

Doing synthetic biology with photosynthetic microorganisms

The use of photosynthetic microbes as synthetic biology hosts for the sustainable production of commodity chemicals and even fuels has received increasing attention over the last decade. The number of studies published, tools implemented, and resources made available for microalgae have increased beyond expectations during the last few years. However, the tools available for genetic engineering in these organisms still lag those available for the more commonly used heterotrophic host organisms. In this mini-review, we provide an overview of the photosynthetic microbes most commonly used in synthetic biology studies, namely cyanobacteria, chlorophytes, eustigmatophytes and diatoms. We provide basic information on the techniques and tools available for each model group of organisms, we outline the state-of-the-art, and we list the synthetic biology tools that have been successfully used. We specifically focus on the latest CRISPR developments, as we believe that precision editing and advanced genetic engineering tools will be pivotal to the advancement of the field. Finally, we discuss the relative strengths and weaknesses of each group of organisms and examine the challenges that need to be overcome to achieve their synthetic biology potential.