The role of the protective shield against UV-C radiation and its molecular interactions in Nostoc species (Cyanobacteria).

Cyanobacteria possess special defense mechanisms to protect themselves against ultraviolet (UV) radiation. This study combines experimental and computational methods to identify the role of protective strategies in Nostoc species against UV-C radiation. To achieve this goal, various species of the genus Nostoc from diverse natural habitats in Iran were exposed to artificial UV-C radiation. The results indicated that UV-C treatment significantly reduced the photosynthetic pigments while simultaneously increasing the activity of antioxidant enzymes. Notably, N. sphaericum ISB97 and Nostoc sp. ISB99, the brown Nostoc species isolated from habitats with high solar radiations, exhibited greater resistance compared to the green-colored species. Additionally, an increase in scytonemin content occurred with a high expression of key genes associated with its synthesis (scyF and scyD) during the later stages of UV-C exposure in these species. The molecular docking of scytonemin with lipopolysaccharides of the cyanobacteria that mainly cover the extracellular matrix revealed the top/side positioning of scytonemin on the glycans of these lipopolysaccharides to form a UV-protective shield. These findings pave the way for exploring the molecular effects of scytonemin in forming the UV protection shield in cyanobacteria, an aspect that has been ambiguous until now.

Cyanobacterial elicitor enhances the biomass of Mentha piperita L. and improves the production of high-value rosmarinic acid under in vitro culture of apical meristem.

BACKGROUND: Rosmarinic acid (RA), like other phenolic compounds, is sources of antioxidants and anti-inflammatory agents in medicinal plants. In vitro culture of plants can improve the medicinal plants' metabolite profile and phenolic compound quantity. To date, various methods have been proposed to increase this medicinal metabolite in plants, among which the use of bioelicitors can be mentioned. In the present study, a native isolate of heterocystous cyanobacteria, Nostoc spongiaeforme var. tenue ISB65, was used to stimulate the production of biomass and content of RA in Mentha piperita L. (peppermint) grown in vitro from apical meristem. Mentha piperita L. explants were inoculated in half strength Murashige and Skoog (1/2 MS) medium containing cyanobacterial lysate (CL). After 50 days of culturing, the growth indices, the content of photosynthetic pigments, and RA in control and treated plants were measured. RESULTS: CL inoculation resulted in a significant enhancement in the vegetative growth indices of peppermint, including root and shoot length, plant biomass and leaf number. The content of photosynthetic pigments also increased in cyanobacteria-treated plants. Inoculation with CL increased the RA content by 2.3-fold, meaning that the plants treated with CL had the highest RA content (7.68 mg. g- 1 dry weight) compared to the control (3.42 mg. g- 1 dry weight). Additionally, HPLC analysis revealed the presence of several auxins in CL. CONCLUSIONS: The presence of auxins and the chemical content of CL such as K+ and Ca2+, as regulators of metabolic pathways and molecular activities of cells, may be responsible for the enhanced growth and phenolic compounds of plants under tissue culture conditions. An improvement in RA content in the tissue culture of medicinal plants treated with CL was reported for the first time in this investigation.

Growth enhancement, metabolic profile improvement, and DXR and TPS2 gene expression changes in Thymus vulgaris L. by cyanobacterial inoculation.

BACKGROUND: In recent decades cyanobacterial species have attracted research attention as potential sources of new biostimulants. In this study, the biostimulant effects of five cyanobacterial suspensions on the growth and essential oil composition of Thymus vulgaris L. were evaluated. The expression of key genes involved in the biosynthesis of thymol and carvacrol, such as DXR and TPS2, were investigated. RESULTS: A pot culture experiment revealed that cyanobacterial application significantly improved T. vulgaris L. growth indices, including plant height, dry and fresh weight, leaf and flower number, leaf area, and photosynthetic pigment content. Total phenol and flavonoid content in inoculated plants also showed a significant increase compared with the control. Anabaena torulosa ISB213 inoculation significantly increased root and shoot biomass by about 65.38% and 92.98% compared with the control, respectively. Nostoc calcicola ISB215 inoculation resulted in the highest amount of essential oil accumulation (18.08 ± 0.62) in T. vulgaris leaves, by about 72.19% compared with the control (10.5 ± 0.50%). Interestingly, the amount of limonene in the Nostoc ellipsosporum ISB217 treatment (1.67%) increased significantly compared with the control and other treatments. The highest expression rates of DXR and TPS2 genes were observed in the treatment of N. ellipsosporum ISB217, with 5.92-fold and 5.22-fold increases over the control, respectively. CONCLUSION: This research revealed the potential of the cyanobacteria that were studied as promising biostimulants to increase the production of biomass and secondary metabolites of T. vulgaris L., which could be a suitable alternative to chemical fertilizers. © 2024 Society of Chemical Industry.

Enhancement of Essential Oil Production and Expression of Some Menthol Biosynthesis-Related Genes in Mentha piperita Using Cyanobacteria.

Background: Mentha piperita L. is one of the most important aromatic crops and is cultivated worldwide for essential oils (EOs). Objectives: The aim of the present study was to investigate the potential of two cyanobacteria, Anabaena vaginicola ISB42 and Nostoc spongiaeforme var. tenue ISB65, as biological-elicitors to improve the growth and essential oil production of M. piperita. Materials and Methods: In this experiment, inoculation of M. piperita with cyanobacteria was performed by adding 1% cyanobacterial suspension to the soil of treated pots on the first time of planting and every 20 days thereafter. The experiment was performed in a randomized complete block design in an experimental greenhouse condition. After 90 days planting, the vegetative growth factors, the content of photosynthetic pigments, as well as the quantity and quality of EOs of treated and control plants were evaluated. Also, quantitative changes in the expression of some menthol biosynthesis-related genes were investigated. Results: Cyanobacterial application led to significant increases in M. piperita growth indices including root and shoot biomass, leaf number, leaf area, node number and ramification, as well as photosynthetic pigments content. The statistical analysis showed a 41-75 % increase in some of these growth indices, especially in Nostoc-treated plants. A. vaginicola and N. spongiaeforme var. tenue inoculation led to a 13% and 25% increase in the EOs content of M. piperita, respectively. The EOs components were also affected by cyanobacterial treatments. According to the statistical analysis, Nostoc-treated plants showed the highest amount of (-)-menthone and (-)-limonene, with a 2.36 and 1.87-fold increase compared to the control. A. vaginicola and N. spongiaeforme var. tenue inoculation also led to 40% and 98% increase in transcript level of (-)-limonene synthase gene, respectively. The expression of the (-)-menthone reductase gene, was also increased by 65% and 55% in response to A. vaginicola and N. spongiaeforme var. tenue application, respectively. Conclusions: Our data demonstrated that in addition to growth enhancement, these two heterocystous cyanobacteria improved the quantity and quality of EOs by up-regulating the key genes involved in the menthol biosynthetic pathway. Based on our results, these cyanobacteria can be considered valuable candidates in the formulation of low-cost and environmentally friendly biofertilizers in sustainable peppermint production.

A feature-based statistical shape model for geometric analysis of the human talus and development of universal talar prostheses.

Statistical data pertaining to anatomic variations of the human talus contain valuable information for advances in biological anthropology, diagnosis of the talar pathologies, and designing talar prostheses. A statistical shape model (SSM) can be a powerful data analysis tool for the anatomic variations of the talus. The main concern in constructing an SSM for the talus is establishing the true geometric correspondence between the talar geometries. The true correspondence complies with biological and/or mathematical homologies on the talar surfaces. In this study, we proposed a semi-automatic approach to establish a dense correspondence between talar surfaces discretized by triangular meshes. Through our approach, homologous salient surface features in the form of crest lines were detected on 49 talar surfaces. Then, the point-wise correspondence information of the crest lines was recruited to create posterior Gaussian process morphable models that non-rigidly registered the talar meshes and consequently established inter-mesh dense correspondence. The resultant correspondence perceptually represented the true correspondence as per our visual assessments. Having established the correspondence, we computed the mean shape using full generalized Procrustes analysis and constructed an SSM by means of principal component analysis. Anatomical variations and the mean shape of the talus were predicted by the SSM. As a clinically related application, we considered the mean shape and investigated the feasibility of designing universal talar prostheses. Our results suggest that the mean shape of (the shapes of) tali can be used as a scalable shape template for designing universal talar prostheses.

Microalgae and Phototrophic Purple Bacteria for Nutrient Recovery From Agri-Industrial Effluents: Influences on Plant Growth, Rhizosphere Bacteria, and Putative Carbon- and Nitrogen-Cycling Genes.

Microalgae (MA) and purple phototrophic bacteria (PPB) have the ability to remove and recover nutrients from digestate (anaerobic digestion effluent) and pre-settled pig manure that can be Utilized as bio-fertilizer and organic fertilizer. The objective of this study was to compare the effectiveness of MA and PPB as organic fertilizers and soil conditioners in relation to plant growth and the soil biological processes involved in nitrogen (N) and carbon (C) cycling. To this end, a glasshouse experiment was conducted using MA and PPB as bio-fertilizers to grow a common pasture ryegrass (Lolium rigidum Gaudin) with two destructive harvests (45 and 60 days after emergence). To evaluate the rhizosphere bacterial community, we used barcoded PCR-amplified bacterial 16S rRNA genes for paired-end sequencing on the Illumina Mi-Seq. Additionally, we used phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis for the detection of putative functional genes associated with N and soil-C cycling. There was a significant increase in plant growth when the soil was amended with PPB, which almost performed as well as the chemical fertilizers. Analysis of the rhizosphere bacteria after the second harvest revealed a greater abundance of Firmicutes than in the first harvest. Members of this phylum have been identified as a biostimulant for plant growth. In contrast, the MA released nutrients more slowly and had a profound effect on N cycling by modulating N mineralization and N retention pathways. Thus, MA could be developed as a slow-release fertilizer with better N retention, which could improve crop performance and soil function, despite nutrient losses from leaching, runoff, and atmospheric emissions. These data indicate that biologically recovered nutrients from waste resources can be effective as a fertilizer, resulting in enhanced C- and N-cycling capacities in the rhizosphere.

226Ra, 238U and Cd adsorption kinetics and binding capacity of two cyanobacterial strains isolated from highly radioactive springs and optimal conditions for maximal removal effects in contaminated water.

Biomass-based decontamination methods are among the most interesting water treatment techniques. In this study, 2 cyanobacterial strains, Nostoc punctiforme A.S/S4 and Chroococcidiopsis thermalis S.M/S9, isolated from hot springs containing high concentrations of radium (226Ra), were studied to be associated with removal of radionuclides (238U and 226Ra) and heavy metal cadmium (Cd) from aqueous solutions. The adsorption equilibrium data was described by Langmuir and Freundlich isotherm models. Kinetic studies indicated that the sorption of 3 metals followed pseudo-second-order kinetics. Effects of biomass concentration, pH, contact time, and initial metal concentration on adsorption were also investigated. Fourier-transform infrared spectroscopy revealed active binding sites on the cyanobacterial biomass. The obtained maximum biosorption capacities were 630 mg g-1 and 37 kBq g-1 for 238U and 226Ra for N. punctiforme and 730 mg g-1 and 55 kBq g-1 for C. thermalis. These 2 strains showed maximum binding capacity 160 and 225 mg g-1, respectively for Cd adsorption. These results suggest that radioactivity resistant cyanobacteria could be employed as an efficient adsorbent for decontamination of multi-component, radioactive and industrial wastewater.

Mycelial growth rate and macro- and micromorphological characteristics of medicinal species of genus Ganoderma (higher Basidiomycetes) from Iran.

Mycelial growth rate is a distinguishing quality that demonstrates continuous variation in different isolates collected from various hosts and locations. The objectives of this research were (1) to reinvestigate the previous identification of Iranian species, and (2) to recognize the best native isolate(s) for cultivation of different Ganoderma species. Of 78 samples collected from different hosts and sites, only 43 mycelia could be purified and examined for further study. Growth rate (GR; Δd/Δt) and growth coefficient (GC; dgh/t) were analyzed by growing isolate culture on 2% malt-extract agar medium (pH 5.5) incubated at 25°C. Macro- and micromorphological studies on mycelia and fruiting bodies such as basidiospore and cutis microcharacters as well as fruiting body quality were used for precise identification. Results revealed that samples belonged to 4 species: G. lucidum, G. applanatum, G. resinaceum, and G. australe. Among all samples, the isolate morphologically identified as G. applanatum showed the best GR (12 mm/day) and good GC (128 mm/day), followed by the 2 other isolates identified as G. resinaceum (GRs and GCs of 11 and 55 mm/day and 10.9 and 43.6 mm/day, respectively).

Analysis of Anabaena vaginicola and Nostoc calcicola from Northern Iran, as rich sources of major carotenoids.

Four major carotenoids of high nutritional significance, including ß-carotene, lycopene, lutein and zeaxanthin were determined in three isolates of heterocystous cyanobacteria, belonging to the genera Anabaena and Nostoc, isolated from Iranian terrestrial and aquatic ecosystems, for the first time. The ultrasonically extracted carotenoids were identified and quantified by a rapid and sensitive isocratic HPLC method and identification was further confirmed by spiking authentic standards and the pattern of the UV-Vis spectra obtained from photo-diode array detector. The results showed that these isolates contain large amounts of four major carotenoids, especially lycopene (up to 24,570 µg/g dry weight, DW) which appears to be the highest reported amount until present; and ß-carotene (up to 8133 µg/g DW) which is comparable with the best natural sources of ß-carotene. Meanwhile, they are rich in the cis-isomers of lycopene and ß-carotene which is important in their bioavailability and health benefits.