Metabolite profiling of the chemosphere of the macroalga ulva (ulvales, chlorophyta) and its associated bacteria

The eukaryotic green marine algae Ulva spp. (Chlorophyta), are usually associated with marine bacteria and exhibit therefore microbe-dependent growth and morphotypes. Ulva spp. might actively affect their microbiome by releasing specific compounds in its chemosphere. For instance, algal oxylipins including polyunsaturated aldehydes (PUAs) derived from polyunsaturated acids (PUFAs) might play an important structuring role for the microbiome. In the present study, Ulva spp. collected at various sampling sites in the lagoon of the Ria Formosa (Portugal) have been studied with respect to (1) their ability to produce polyunsaturated aldehydes and (2) their ability to communicate with their surrounding bacteria via infochemicals. Lipoxygenase/hydroperoxidelyase mediated transformations convert polyunsaturated fatty acids into various oxylipins. These fatty acid transformations are highly diverse in marine algae and play a crucial role in e.g., signaling, chemical defense, and stress response often mediated through polyunsaturated aldehydes (PUAs). In this study, Ulva spp. were surveyed for PUAs. Ulva species with sea-lettuce like morphotype were demonstrated to produce elevated amounts of volatile C10-polyunsaturated aldehydes (2,4,7-decatrienal and 2,4-decadienal) upon tissue damage in contrast to Ulva species with tube-like morphotype. Moreover, morphogenetic and phylogenetic analyses of the collected Ulva species revealed chemotaxonomic significance of the perspective biosynthetic pathways. The aldehydes are derived from omega-3 and omega-6 polyunsaturated fatty acids (PUFA) with 20 or 18 carbon atoms including eicosapentaenoic acid (C20:5 n-3), arachidonic acid (C20:4 n-6), stearidonic acid (C18:4 n-3), and gamma-linolenic acid (C18:3 n-6). As first evidences in this study, it was found that lipoxygenase-mediated (11-LOX and 9-LOX) eicosanoid and octadecanoid pathways catalyze the transformation of C20- and C18-polyunsaturated fatty acids into PUAs and concomitantly into short chain hydroxylated fatty acids. Ulva mutabilis Føyn (sl) with tube-like morphotype was used as an objective to investigate the chemical mediated interaction (infochemicals) within the chemosphere of tripartite community consisting of U. mutabilis and its associated marine bacteria i.e., Roseobacter and Cytophaga species. In the absence of these bacteria (axenic conditions), U. mutabilis forms callus-like colonies. However, the combination of the two bacterial strains, Roseobacter sp. and Cytophaga sp. can completely restore the morphogenesis of U. mutabilis forming a symbiotic tripartite community. The exo-metabolome of the chemosphere of this tripartite community was surveyed along with the biological metadata. Two different approaches and cultivation conditions i.e., sterile 25 L bioreactor cultures and non-sterile 200 L outdoor aquacultures were conducted which cultures were inoculated with axenic seven days old germlings. Indeed, it was feasible to observe the whole life cycle of the gametophyte under these conditions when the appropriate bacteria were inoculated as well. Hereby, the medium did not need to be changed. Bioassays revealed that U. mutabilis passed through three statuses of gametogenesis inducibility which can be distinguished whether Ulva is able to onset the gametogenesis: (1) gametogenesis is not inducible, (2) gametogenesis can be induced or (3) it starts even spontaneously. The nutrient depletion over the reproductive cycle shows that the utilization rate of nitrate as a limiting growth factor was significantly high during the inducible status, when the macroalgae was growing. The waterborne metabolites were extracted by solid phase extraction. The samples were directly analyzed by ultra-high performance liquid chromatography (UHPLC) and by gas chromatography (after derivatization) coupled with a time-of-flight mass spectrometer (TOF-MS). Interestingly, discriminant analysis proofed that all waterborne metabolites obtained either from GC-MS or LC-MS were corresponding to the inducibility status of gametogenesis of U. mutabilis in both cultivation conditions. Even more interesting, many unknown biomarkers were found to be common in both bioreactor cultures and aquaculture, insuring the high probability of using these biomarkers as indicators to determine the growth phases corresponding to the status of gametogenesis inducibility in U. mutabilis under any cultivation condition in future land based aquacultures. Moreover, the present study revealed remarkable metabolic fingerprints which might due to the adaptation of U. mutabilis to changes in its surrounding environment. For instance, the algal biomarker 2,4,6-tribromophenol was detected in the chemosphere of the tripartite community under sterile cultivation (bioreactor) but not in the well-defined bacterial community under non-sterile cultivation (aquaculture). In summary, the changes of the metabolite profile between the growth phases were significant. Therefore, various statues in algal growth and life cycle can be predicted based on the dynamics of waterborne metabolites. This knowledge will be essential in order to maintain land based aquacultures providing economical relevant amounts of biomasses

Macroalgal–bacterial interactions: identification and role of thallusin in morphogenesis of the seaweed Ulva (Chlorophyta)

Macroalgal microbiomes have core functions related to biofilm formation, growth, and morphogenesis of seaweeds. In particular, the growth and development of the sea lettuce Ulva spp. (Chlorophyta) depend on bacteria releasing morphogenetic compounds. Under axenic conditions, the macroalga Ulva mutabilis develops a callus-like phenotype with cell wall protrusions. However, co-culturing with Roseovarius sp. (MS2) and Maribacter sp. (MS6), which produce various stimulatory chemical mediators, completely recovers morphogenesis. This ecological reconstruction forms a tripartite community which can be further studied for its role in cross-kingdom interactions. Hence, our study sought to identify algal growth- and morphogenesis-promoting factors (AGMPFs) capable of phenocopying the activity of Maribacter spp. We performed bioassay-guided solid-phase extraction in water samples collected from U. mutabilis aquaculture systems. We uncovered novel ecophysiological functions of thallusin, a sesquiterpenoid morphogen, identified for the first time in algal aquaculture. Thallusin, released by Maribacter sp., induced rhizoid and cell wall formation at a concentration of 11 pmol l-1. We demonstrated that gametes acquired the iron complex of thallusin, thereby linking morphogenetic processes with intracellular iron homeostasis. Understanding macroalgae-bacteria interactions permits further elucidation of the evolution of multicellularity and cellular differentiation, and development of new applications in microbiome-mediated aquaculture systems.FCT: UID/Multi/04326/2019; UIDB/04326/2020; CCMAR/ID/16/2018; CEECINST/00114/2018. German Research Foundation (DFG) CRC1127; European Union (EU) 642575; ASSEMBLE 227799; COST Action 'Phycomorph' FA1406.info:eu-repo/semantics/publishedVersio

Detection of glucose in the growth media of Ulva lactuca using a Ni-Cu/TiO2/Ti self-assembly nanostructure sensor under the influence of crude oil

Pollution of the marine environment by crude oil is considered as a significant problem. Interestingly, the existence of algae in the marine ecosystem contributes significantly to maintaining the equilibrium of marine life and, consequently, has the ability to alert the ecosystem to the pollution by using their waterborne molecules including the photosynthetic products. The main aim of this work is to develop an electrochemical sensor (EC) for the detection of the concentration of glucose found in the growth media of Ulva sp. as a photosynthetic product or decomposed substance under polluted conditions. A Ni-Cu/TiO2/Ti array electrode was fabricated, where highly-ordered self-organized nanocrystalline TiO2 was prepared via anodization and annealing processes on a Ti substrate and Ni-Cu alloy nanoparticles were electrodeposited by linear sweep voltammetry. The chemical composition, structure and morphology characterization were carried out by high-resolution scanning electron microscopy and energy dispersive X-ray spectroscopy analyses. The ideal non-enzymatic sensor with large and constant sensitivity (402 μA mM−1 cm−2) and low detection limit (495 μM) was successfully employed to detect glucose excreted by Ulva lactuca under oil pollution under alkaline condition. The present study succeeded to combine between the ecological role of algae and electrochemical sensors to be used collectively as an indicator of the oil spillage into the seawater. Keywords: Non-enzymatic glucose sensor, Nutrient, Ni-Cu/TiO2/Ti, Algae, Ulva lactuc

Part B: Improvement of the Optical Properties of Cellulose Nanocrystals Reinforced Thermoplastic Starch Bio-Composite Films by Ex Situ Incorporation of Green Silver Nanoparticles from <i>Chaetomorpha linum</i>

The study was used in the context of realigning novel low-cost materials for their better and improved optical properties. Emphasis was placed on the bio-nanocomposite approach for producing cellulose/starch/silver nanoparticle films. These polymeric films were produced using the solution casting technique followed by the thermal evaporation process. The structural model of the bio-composite films (CS:CL-CNC7:3–50%) was developed from our previous study. Subsequently, in order to improve the optical properties of bio-composite films, bio-nanocomposites were prepared by incorporating silver nanoparticles (AgNPs) ex situ at various concentrations (5–50% w/w). Characterization was conducted using UV-Visible (UV-Vis), Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) to understand the structure–property relationships. The FTIR analysis indicated a reduction in the number of waves associated with the OH functional groups by adding AgNPs due to the formation of new hydrogen bonds between the bio-composite matrix and the CL-WE-AgNPs. Based on mathematical equations, the optical bandgap energy, the energy of Urbach, the edge of absorption (Ed), and the carbon clusters (N) were estimated for CS:CL-CNC and CS:CL-CNC-AgNPs (5–50%) nanocomposite films. Furthermore, the optical bandgap values were shifted to the lower photon energy from 3.12 to 2.58 eV by increasing the AgNPs content, which indicates the semi-conductor effect on the composite system. The decrease in Urbach’s energy is the result of a decrease in the disorder of the biopolymer matrix and/or attributed to an increase in crystalline size. In addition, the cluster carbon number increased from 121.56 to 177.75, respectively, from bio-composite to bio-nanocomposite with 50% AgNPs. This is due to the presence of a strong H-binding interaction between the bio-composite matrix and the AgNPs molecules. The results revealed that the incorporation of 20% AgNPs into the CS:CL-CNC7:3–50% bio-composite film could be the best candidate composition for all optical properties. It can be used for potential applications in the area of food packaging as well as successfully on opto-electronic devices

Time Course Exo-Metabolomic Profiling in the Green Marine Macroalga Ulva (Chlorophyta) for Identification of Growth Phase-Dependent Biomarkers

The marine green macroalga Ulva (Chlorophyta) lives in a mutualistic symbiosis with bacteria that influence growth, development, and morphogenesis. We surveyed changes in Ulva’s chemosphere, which was defined as a space where organisms interact with each other via compounds, such as infochemicals, nutrients, morphogens, and defense compounds. Thereby, Ulva mutabilis cooperates with bacteria, in particular, Roseovarius sp. strain MS2 and Maribacter sp. strain MS6 (formerly identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6). Without this accompanying microbial flora, U. mutabilis forms only callus-like colonies. However, upon addition of the two bacteria species, in effect forming a tripartite community, morphogenesis can be completely restored. Under this strictly standardized condition, bioactive and eco-physiologically-relevant marine natural products can be discovered. Solid phase extracted waterborne metabolites were analyzed using a metabolomics platform, facilitating gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analysis, combined with the necessary acquisition of biological metadata. Multivariate statistics of the GC-MS and LC-MS data revealed strong differences between Ulva’s growth phases, as well as between the axenic Ulva cultures and the tripartite community. Waterborne biomarkers, including glycerol, were identified as potential indicators for algal carbon source and bacterial-algal interactions. Furthermore, it was demonstrated that U. mutabilis releases glycerol that can be utilized for growth by Roseovarius sp. MS2

Geospatial Evaluation of Cropping Pattern and Cropping Intensity Using Multi Temporal Harmonized Product of Sentinel-2 Dataset on Google Earth Engine

Due to the declining land resources over the past few decades, the intensification of land uses has played a significant role in balancing the ever-increasing demand for food in developing nations such as India. To optimize agricultural land uses, one of the crucial indicators is cropping intensity, which measures the number of times a single parcel of land is farmed. Therefore, it is imperative to create a timely and accurate cropping intensity map so that landowners and agricultural planners can use it to determine the best course of action for the present and for the future. In the present study, we have developed an algorithm on Google Earth Engine (GEE) to depict cropping patterns and further fused it with a GIS environment to depict cropping intensity in the arid western plain zone of Rajasthan, India. A high-resolution multi-temporal harmonized product of the Sentinel-2 dataset was incorporated for depicting the growth cycle of crops for the year 2020–2021 using the greenest pixel composites. Kharif and Rabi accounted for 73.44% and 26.56% of the total cultivated area, respectively. Only 7.42% was under the double-cropped area to the total cultivated area. The overall accuracy of the classified image was 90%. For the Kharif crop, the accuracy was 95%, while for Rabi and the double-cropped region, the accuracy was 88%, with a kappa coefficient of 0.784. The present study was able to depict the seasonal plantation system in arid arable land with higher accuracy. The proposed work can be used to monitor cropping patterns and cost-effectively show cropping intensities

Development of Novel Microcomposite Materials from Coal Fly Ash and Incense Sticks Ash Waste and Their Application for Remediation of Malachite Green Dye from Aqueous Solutions

Coal fly ash (CFA) is one of the major pollutants around the whole world. At the same time, incense stick ash (ISA) is another waste that is generated in huge amounts in Southeast Asia. Both of these wastes are rich in different types of minerals; for instance, CFA is rich in alumina, silica, and ferrous, while incense sticks ash is rich in calcium and silica. ISA has intermediate to trace amounts of ferrous, alumina, and magnesium. The addition of alkali-rich materials with high Al and Si-containing CFA helps in the formation of zeolites or geopolymers. So, in the current research work, the authors have prepared a CFA: ISA mixture in the ratio of 1:1, followed by mixing them with NaOH, CaOH2, and KOH in a dry state in a crucible. Further, all these mixtures were then calcined at 600 °C for six hours in a muffle furnace. Further, the developed products were analyzed by various sophisticated instruments for detailed information. Finally, the developed material’s potential was assessed for the remediation of malachite green from the aqueous solution by batch adsorption study. The developed adsorbents efficiently removed the dye from the aqueous solutions within one hour. The kinetic study revealed that the dye removal followed a pseudo-second-order reaction. Finally, the developed material was also assessed for its suitability as an adsorbent by observing the effect of leaching of potassium, aluminum, and silica from the adsorbent surface into the water systems. Such approaches will solve the problem of solid waste disposal arising from both the ashes

Marine Alga <i>Ulva fasciata</i>-Derived Molecules for the Potential Treatment of SARS-CoV-2: An <i>In Silico</i> Approach

SARS-CoV-2 is the causative agent of the COVID-19 pandemic. This in silico study aimed to elucidate therapeutic efficacies against SARS-CoV-2 of phyco-compounds from the seaweed, Ulva fasciata. Twelve phyco-compounds were isolated and toxicity was analyzed by VEGA QSAR. Five compounds were found to be nonmutagenic, noncarcinogenic and nontoxic. Moreover, antiviral activity was evaluated by PASS. Binding affinities of five of these therapeutic compounds were predicted to possess probable biological activity. Fifteen SARS-CoV-2 target proteins were analyzed by the AutoDock Vina program for molecular docking binding energy analysis and the 6Y84 protein was determined to possess optimal binding affinities. The Desmond program from Schrödinger’s suite was used to study high performance molecular dynamic simulation properties for 3,7,11,15-Tetramethyl-2-hexadecen-1-ol—6Y84 for better drug evaluation. The ligand with 6Y84 had stronger binding affinities (−5.9 kcal/mol) over two standard drugs, Chloroquine (−5.6 kcal/mol) and Interferon α-2b (−3.8 kcal/mol). Swiss ADME calculated physicochemical/lipophilicity/water solubility/pharmacokinetic properties for 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, showing that this therapeutic agent may be effective against SARS-CoV-2

Green Synthesis and Characterization of LED-Irradiation-Responsive Nano ZnO Catalyst and Photocatalytic Mineralization of Malachite Green Dye

The green synthesis of nanoparticles is an emerging branch of nanotechnology in recent times, as it has numerous advantages such as sustainability, cost-effectiveness, biocompatibility, and eco-friendliness. In the present research work, the authors synthesized ZnO nanoparticles (ZnO NPs) by a green and eco-friendly method. The synthesized ZnO NPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopic techniques. The calculated average crystallite size of ZnO NPs was observed at 36.73 nm and FESEM images clearly showed the cylindrical shape of nanoparticles. The absorption peak at 531 cm&minus;1 was observed in the FTIR spectrum of the ZnO NPs sample, which also supports the formation of the ZnO wurtzite structure. Finally, the synthesized ZnO NPs potential was analyzed for the remediation of malachite green from an aqueous solution. The ZnO NPs showed a desirable photocatalytic nature under LEDs irradiation