Green Strain Research Articles

Appraisal of the Genus Pleurastrum (Chlorophyta) Based on Molecular and Climate Data

Two green microalgal strains, CCCryo 469-16 and CCCryo 470-16, were isolated from samples of Antarctic microflora. Their morphology and 18S rRNA sequences indicated a phylogenetic relationship with strains of the genera Chlorococcum Meneghini, Macrochloris Korshikov, and Pleurastrum Chodat. The last genus is considered particularly problematic as it underwent several revisions. Moreover, its type strain, P. insigne SAG 30.93, was recently demonstrated to coincide genetically with the authentic strain of Chlorococcum oleofaciens from an 18S rRNA phylogeny. This deprived the genus Pleurastrum of an important type reference. Thus, the molecular markers rbcL, tufA, and ITS were employed to identify the Antarctic isolates more precisely. Several other microalgae related to our isolates were obtained from international culture collections for comparison. The obtained results allowed the re-establishment of strain P. insigne SAG 30.93 as the reference strain and the definition of the molecular borders of both genera Pleurastrum and Chlorococcum. Based on our findings, several Chlorococcum species are now re-attributed to Pleurastrum, as well as Macrochloris rubrioleum, here re-named Pleurastrum rubrioleum comb. nov., to which the Antarctic isolates also belong. Finally, a relationship between Pleurastrum lineages and climate zones was established.

Torsional buckling response of FG porous thick truncated conical shell panels reinforced by GPLs supporting on Winkler elastic foundation

In the present research, torsional buckling response of thick truncated conical shell panels supporting on Winkler-type elastic medium has been surveyed. The shell is constructed from a porous metal material reinforced by graphene platelets (GPLs) in which the porosity and volume weight fraction of nanofillers are graded along the thickness of shell. Three functions for porosity distribution and five patterns of GPLs are examined. To estimate the Young modulus of the shell, Tsai-Halpin micromechanical model, and for its mass density, extended rule of mixture is employed. Linear theory of 3D elasticity in conjunction with the virtual work principle and numerical graded finite element method (FEM) are applied to derive the state of equilibrium in pre-buckling mode. Torsional buckling forces are derived by applying nonlinear Green strains and by deriving geometric stiffness matrix of the system. The effect of various parameters such as coefficient of porosity, various distributions of porosity and different nanofiller patterns, weight fraction of graphene nanofillers, semi vertex angle of cone, span angle, stiffness of elastic medium and various boundary conditions on torsional buckling loads of functionally graded (FG) porous truncated conical panel reinforced by GPLs have been presented. The main purpose of this research is obtaining the best distribution of porosity and GPLs pattern and investigating the influence of adding nano particles on the torsional buckling forces of the shell. Results denote that employing GPL-X pattern in conjunction with porosity distribution 1 provides the maximum value of buckling loads. Besides by adding the nano particles, the amount of buckling loads will increase 100%.

Metabolomic and transcriptomic analyses reveal the biosynthetic mechanisms of pigments and main taste compounds in an albino tea cultivar.

Significant variations in leaf colours, pigment contents, and main taste compounds in young shoots from albino tea plants (Camellia sinensis) influence tea flavour. However, the seasonal metabolic pattern and molecular regulatory mechanism of these metabolites remain largely elusive. Herein, we conducted morphological, biochemical, metabolomic and transcriptomic analyses between an albino tea cultivar 'Zhonghuang 3' ('ZH3') and a green strain 'Tai cha 15' ('TC15') at four-time points (April 12, May 31, July 14, and August 17) to elucidate dynamic changes in these compounds and predict the relationships among transcription factors (TFs), target genes (TGs), and metabolite abundance. Generally, leaf colours and pigment contents were significantly lighter and lower, respectively, in 'ZH3' than in 'TC15' from spring to summer, but were subsequently similar. Compared to 'TC15', 'ZH3' had a lower and broader phenol/ammonia ratio as well as stable caffeine content and showed more significantly different metabolites and differentially expressed genes. The relationship between pigments, main taste compounds, and their biosynthetic genes, as well as TFs and their TGs, had genetic specificity. These results suggested that the biosynthesis of these compounds was probably both season- and variety-dependent. In total, 12 models of the TF-TG-metabolite regulatory network were proposed to uncover the biosynthetic and regulatory mechanisms of these metabolites in tea plants. A high correlation was observed between some structural genes and TFs with the accumulation of these metabolites. These findings provide novel insights into the regulatory mechanisms underlying accumulation of pigments and main taste compounds in tea plants.

Pure torsion for incompressible hyperelastic materials of Valanis–Landel form

The stretch-based formulation of basic problems for incompressible isotropic hyperelastic materials has been the subject of renewed recent attention largely motivated by application to modelling the mechanical response of soft tissues. Here, we are concerned with this formulation of the classic problem of simple torsion of a circular cylinder that has been primarily in the past investigated by employing the classical approach of Rivlin in terms of invariants of the Cauchy–Green strain tensor. Attention is focused on examining the resultant axial force necessary to sustain pure torsion, thereby investigating the Poynting effect, and the resultant moment needed to generate the twist. General results for the resultant force and moment are obtained for all hyperelastic materials that can be modelled in the celebrated separable Valanis–Landel form. These expressions are specialized for the one-term Ogden model to provide explicit results valid for all strain-stiffening exponents in this model. Some particular examples are provided, mainly for even values of the exponent. A notable result obtained for the Ogden model is that for values of the hardening exponent n in that model for which n ≤ 6 , one obtains the classical Poynting effect, whereas for n > 6 , a reverse Poynting effect always occurs for sufficiently small twist.

Single-cell adaptations shape evolutionary transitions to multicellularity in green algae

The evolution of multicellular life has played a pivotal role in shaping biological diversity. However, we know surprisingly little about the natural environmental conditions that favour the formation of multicellular groups. Here we experimentally examine how key environmental factors (predation, nitrogen and water turbulence) combine to influence multicellular group formation in 35 wild unicellular green algae strains (19 Chlorophyta species). All environmental factors induced the formation of multicellular groups (more than four cells), but there was no evidence this was adaptive, as multicellularity (% cells in groups) was not related to population growth rate under any condition. Instead, population growth was related to extracellular matrix (ECM) around single cells and palmelloid formation, a unicellular life-cycle stage where two to four cells are retained within a mother-cell wall after mitosis. ECM production increased with nitrogen levels resulting in more cells being in palmelloids and higher rates of multicellular group formation. Examining the distribution of 332 algae species across 478 lakes monitored over 55 years, showed that ECM and nitrogen availability also predicted patterns of obligate multicellularity in nature. Our results highlight that adaptations of unicellular organisms to cope with environmental challenges may be key to understanding evolutionary routes to multicellular life.

Root colonization of industrial hemp (Cannabis sativa L.) by the endophytic fungi Metarhizium and Pochonia improves growth

Metarhizium is an endophytic, insect pathogenic fungus. Here we investigated the time-course of systemic and rhizospheric colonization by Metarhizium and its influence on the growth of industrial hemp (Cannabis sativa L.). Fungal colonization of hemp root, stem and leaf as well as rhizospheric soil, and agronomic parameters of hemp, were tested in four Metarhizium species with broad- (Metarhizium robertsii, Metarhizium anisopliae, Metarhizium brunneum) and narrow-insect (Metarhizium acridum) host ranges, as well as Pochonia chlamydosporia, a phylogenetically related endophytic fungus that is a nematode pathogen. Root and rhizosphere colonization were found in all Metarhizium species and Pochonia at 10, 20 and 30 days post-inoculation. Pochonia showed greatest root colonization compared to that of all Metarhizium species. Endophytic root colonization by Metarhizium was confirmed by confocal fluorescence microscopy using green fluorescent protein-expressing fungal strains. The genes, cat, mpl and EF1α were tested using a qPCR assay for Metarhizium and hemp. Root colonization by Metarhizium and Pochonia positively influenced shoot length, stem weight and root weight of hemp during the early stages of colonization. Our results suggest the potential for the application of Metarhizium and Pochonia as biocontrol and plant growth promoter agents during hemp colonization.

Whey permeate as a phosphorus source for algal cultivation.

Microalgal cultivation for biodiesel and feed requires recycled nutrient resources for a sustainable long-term operation. Whey permeate (WP) from dairy processing contain high organic load (lactose, oils, proteins) and nitrogen (recourses tested for microalgal cultivation) and organic phosphorus (P) that has not yet been tested as a P source for microalgal cultivation. We explored the potential of green algae strains (brackish) and polyculture (freshwater) in exploiting P from WP added to a medium based on either seawater (7 psu) or landfill leachate. Both strains showed a capacity of using organic P in WP with equal growth rates (0.94-1.12 d-1 ) compared to chemical phosphate treatments (0.88-1.07 d-1 ). The polyculture had comparable growth rate (0.25-0.57 d-1 ) and biomass yield (152.1-357.5 mg L-1 ), and similar or higher nutrient removal rate in the leachate-WP medium (1.3-6.4 mg L-1 day-1 nitrogen, 0.2-1.1 mg L-1 day-1 P) compared to the leachate-chemical phosphate medium (1.2-4.7 mg L-1 day-1 nitrogen, 0.3-1.4 mg L-1 day-1 P). This study showed that WP is a suitable P source for microalgal cultivation over a range of salinities. To date, this is the first study demonstrating that raw WP can replace mineral P fertilizer for algal cultivation.

Numerical Study on the Buckling Behavior of FG Porous Spherical Caps Reinforced by Graphene Platelets

The buckling response of functionally graded (FG) porous spherical caps reinforced by graphene platelets (GPLs) is assessed here, including both symmetric and uniform porosity patterns in the metal matrix, together with five different GPL distributions. The Halpin-Tsai model is here applied, together with an extended rule of mixture to determine the elastic properties and mass density of the selected shells, respectively. The equilibrium equations of the pre-buckling state are here determined according to a linear three-dimensional (3D) elasticity basics and principle of virtual work, whose solution is determined from classical finite elements. The buckling load is, thus, obtained based on the nonlinear Green strain field and generalized geometric stiffness concept. A large parametric investigation studies the sensitivity of the natural frequencies of FG porous spherical caps reinforced by GPLs to different parameters, namely, the porosity coefficients and distributions, together with different polar angles and stiffness coefficients of the elastic foundation, but also different GPL patterns and weight fractions of graphene nanofillers. Results denote that the maximum and minimum buckling loads are reached for GPL-X and GPL-O distributions, respectively. Additionally, the difference between the maximum and minimum critical buckling loads for different porosity distributions is approximately equal to 90%, which belong to symmetric distributions. It is also found that a high weight fraction of GPLs and a high porosity coefficient yield the highest and lowest effects of the structure on the buckling loads of the structure for an amount of 100% and 12.5%, respectively.

Cultivation of Pseudochlorella pringsheimii for biodiesel production in a scalable indoor photobioreactor: case studies from Egypt

BackgroundEnhancement of lipid accumulation is the major strategy to improve the commercial feasibility of microalgae as a source for biodiesel production. Pseudochlorella pringsheimii (Formally was named as Chlorella ellipsoidea) green microalgae strain was chosen with respect to their ability as a potential source to produce high lipids content, could be used for the production of biofuel, which can be an alternative renewable energy source instead of fossil fuels. ResultsInitially, the Pseudochlorella pringsheimii microalgae was evaluated on the basis of tested at Lab scales 2 L by applicable different nutrient individual of N, P, Fe conditions in BBM medium concentrations for choosing the best concentrations induce lipid contents and productivity to cultivate in large scale in the 2000 L PBR. The suitable concentrations of nutrients with highest lipid contents were obtained under deficient of nitrogen (1.25 gL−1, limited N) and phosphorus (0.1 mg L−1, limited P) coupled with high iron concentration (10 mg L, rich Fe) and CO2 (6%). Therefore, their collective of nutrients was applied to culture of microalgae cells at large scale in 2000 L photobioreactor (PBR model), which, this techniques was used to quantify high lipid contents (25% w/w) and high lipid productivity (74.07 mgL−1 day−1). The inducted lipid conversion to biodiesel via transestrification process was 91.54 ± 1.43%. The fatty acid methyl esters (FAMEs profile by means of GC/MS resulted in C16:0, C18:1, C18:2, C18:3 as a main constituents. With regard to physical–chemical property (such as density, kinematic viscosity, gravity, and certain number), the Pseudochlorella pringsheimii biodiesel have biofuel properties, in accordance with appropriate biodiesel properties, as ASTM and EU standards, that thereby referring to high quality biodiesel. ConclusionsPseudochlorella pringsheimii cultured in large scale in photobioreactor under stress condition have a high potential of lipids production with high quality of FAMEs that can be used as a promising biodiesel fuel. It has also a potential to be applied for commercialization based on the techno-economic and environmental impacts. Highlights*Pseudochlorella pringsheimii showed a high potential of lipids 25% lipid accumulation.*Pseudochlorella pringsheimii could be cultured at large scale in potobioreactor, as potential feedstock for biodiesel production.*Bodiesel FAME contains C 16:0, C 18:1 and C 18:2 as a maim FAM.*N, P starvation collective with high Fe3+was the main driver behind lipid accumulation.*Pseudochlorella pringsheimii biodiesel have appropriate biodiesel properties, as ASTM and EU standards.*C. ellipsoidea can be used as a potential feedstock for biodiesel production.

Reduced representations of assumed fields for Hu–Washizu solid-shell element

Mixed eight-node (hexahedron) solid-shell elements based on the standard or partial version of the three-field Hu–Washizu (HW) functionals are developed for Green strain. Three reduced representations of the assumed stress/strain fields are selected. They improve effectiveness, yet retaining good accuracy and convergence properties. At the outset, the standard HW functional and the assumed stress/strain representations of the 3D solid element B8-15P (Weissman in Int J Numer Methods Eng 39:2337–2361, 1996) are used to derive a solid-shell element with 51 parameters. To eliminate locking, the ANS method is applied to the thickness strain (Betsch and Stein in Commun Numer Methods Eng 11:899–909, 1995) and to the transverse shear strain (Dvorkin and Bathe in Eng Comput 1:77–88, 1984). It is a correct element which, however, yields too large displacements for coarse meshes and trapezoidal through-thickness shapes. To improve the above formulation, the zeta -independent reduced representations of the assumed stress/ strain fields are selected and the transformations to Cartesian components are modified. The thickness strain is enhanced by the EAS method. The element with 35 parameters is derived from the standard/enhanced HW functional, but, to further reduce the assumed fields, partial/enhanced HW functionals are constructed from the 3D potential energy by applying the Lagrange multiplier method only to selected strain components. In the element with 27 parameters, this is applied to the constant in-plane strain and to the transverse shear strain while in the element with 19 parameters, to the constant in-plane strain only.Two other modifications are implemented to enhance the behavior of these elements: (A) the skew coordinates are used in the reduced representations of the in-plane stress/strain (Wisniewski and Turska in Int J Numer Methods Eng 90:506–536, 2012), and (B) the Residual Bending Flexibility correction of the transverse shear stiffness (MacNeal in Comput Struct 8(2):175–183, 1978) is adapted. Finally, the performance of the proposed solid-shell HW elements is demonstrated on several linear and non-linear examples for the linear elastic material and the hyper-elastic material. The proposed elements are compared to each other and to the best existing elements of this class.

Mapping the shape and dimension of three-dimensional Lagrangian coherent structures and invariant manifolds

We introduce maps of Cauchy–Green strain tensor eigenvalues to barycentric coordinates to quantify and visualize the full geometry of three-dimensional deformation in stationary and non-stationary fluid flows. As a natural extension of Lagrangian coherent structure diagnostics, which provide separate scalar fields and a one-dimensional quantification of fluid deformation, our barycentric mapping visualizes the role of all three Cauchy–Green eigenvalues (or rates of stretching) in a single plot through a novel stretching coordinate system. The coordinate system is based on the distance from three distinct limiting states of deformation that correspond with the dimension of the underlying invariant manifolds. One-dimensional axisymmetric deformation (sphere to rod deformation) corresponds to one-dimensional unstable manifolds, two-dimensional axisymmetric deformation (sphere to disk deformation) corresponds to two-dimensional unstable manifolds and the rare three-dimensional isometric case (sphere to sphere translation and rotation) corresponds to shear-free elliptic Lagrangian coherent structures (LCSs). We provide methods to visualize the degree to which fluid deformation approximates these limiting states, and tools to quantify differences between flows based on the compositional geometry of invariant manifolds in the flow. We also develop a simple analogue for bilinearly representing and plotting both rates of stretching and rotation as a single vector. As with other LCS techniques, these diagnostics define frame-indifferent material features in the flow. We provide multiple computed examples of LCS and momentum transport barriers, and show advantages over other coherent structure diagnostics.

Three-dimensional growth simulation of swellable soft materials based on CS-FEM

In this paper, a three-dimensional numerical framework for modeling growth of swellable soft materials at large deformation is established based on the cell-based smooth finite element method, and the multiplicative decomposition scheme of deformation gradient is given. The second P-K stress and Green's strain tensor are selected as work conjugate pairs, and the corresponding mathematical expressions of stiffness matrix and geometric stiffness matrix are derived. The numerical method is implemented based on Matlab platform, and the isotropic and anisotropic growth behaviors of swellable soft materials are simulated respectively. The results show that anisotropic growth will inhibit the deformation of expandable soft materials compared with isotropic growth. The simulation results are compared with the calculation results in the existing literature. The comparison results show that the characteristics and the morphological mode are in good agreement, which proves the effectiveness of the numerical framework in simulating the growth behavior of expandable soft materials at large deformation, and is able to reveal the mechanical mechanism of the plant growth phenomenon in nature.

THE USE OF A SELECTED FAST-SEDIMENTATION GREEN MICROALGAE FOR WASTEWATER TREATMENT

The use of microalgae in biotechnological processes, such as bioenergy production and wastewater treatment have been and continue to be of great interest. However, the commercialization of their potential is hindered due to various technical challenges, with biomass harvesting being the largest and most expensive energy consumer among them. Therefore, a major challenge is in finding an efficient harvesting method with high economic feasibility. In this study, a rapid-sedimentation freshwater green microalga was used for batch treatment of artificial wastewater. This strain, in addition to its ability to efficiently remove and use N, P as a source of nutrients, has the advantage of a fast-sedimentation innate feature that allows for a rapid biomass settling (less than 10 minutes) without the addition of any flocculant. This green microalgal strain grows in the form of macrocolonies that significantly favor harvesting by rapid natural gravitational sedimentation. Thus, as this microalga will not require centrifugal harvesting, which is expensive and energy-consuming, its use at both bench and pilot scale could be a promising, cost-effective, and environmentally friendly approach for biotechnological applications.

Tolerance to allelopathic inhibition by free fatty acids in five biofuel candidate microalgae strains

Contaminating organisms (grazers, pathogens, competitors) and self-inhibition by algae-produced allelopathic chemicals are two issues that may limit the productivity of algal cultivation for bioproducts. One potential solution is to identify algal strains that are not affected by allelopathic inhibition even while undesirable organisms are suppressed. Here we used two experiments to test how sensitivity to allelopathy varies across algae. In the first experiment, we tested the sensitivity of five biofuel candidate green algae strains to two allelopathic compounds (i.e., free fatty acids) and found that the degree of inhibition depends strongly on both the species and specific compound. In the second experiment, we exposed one alga (Chlorella) to the sterile-filtered medium of each species, and found that the concentration of free fatty acids released into the media predicted Chlorella's growth response. This provides a better understanding of how the production of, and sensitivity to, allelopathic compounds determines algal productivity.

Ex vivo bovine liver nonlinear viscoelastic properties: MR elastography and rheological measurements

IntroductionKnowledge of the nonlinear viscoelastic properties of the liver is important, but the complex tissue behavior outside the linear viscoelastic regime has impeded their characterization, particularly in vivo. Combining static compression with magnetic resonance (MR) elastography has the potential to be a useful imaging method for assessing large deformation mechanical properties of soft tissues in vivo. However, this remains to be verified. Therefore this study aims first to determine whether MR elastography can measure the nonlinear mechanical properties of ex vivo bovine liver tissue under varying levels of uniform and focal preloads (up to 30%), and second to compare MR elastography-derived complex shear modulus with standard rheological measurements. MethodNine fresh bovine livers were collected from a local abattoir, and experiments were conducted within 12hr of death. Two cubic samples (∼10 × 10 × 10 cm3) were dissected from each liver and imaged using MR elastography (60 Hz) under 4 levels of uniform and focal preload (1, 10, 20, and 30% of sample width) to investigate the relationship between MR elastography-derived complex shear modulus (G∗) and the maximum principal Right Cauchy Green Strain (C11). Three tissue samples from each of the same 9 livers underwent oscillatory rheometry under the same 4 preloads (1, 10, 20, and 30% strain). MR elastography-derived complex shear modulus (G∗) from the uniform preload was validated against rheometry by fitting the frequency dependence of G∗ with a power-law and extrapolating rheometry-derived G∗ to 60 Hz. ResultsMR elastography-derived G∗ increased with increasing compressive large deformation strain, and followed a power-law curve (G∗ = 1.73 × C11−0.38, R2 = 0.96). Similarly, rheometry-derived G∗ at 1 Hz, increasing from 0.66 ± 1.03 kPa (1% strain) to 1.84 ± 1.65 kPa (30% strain, RM one-way ANOVA, P < 0.001), and the frequency dependence of G∗ followed a power-law with the exponent decreasing from 0.13 to 0.06 with increasing preload. MR elastography-derived G∗ was 1.4–3.1 times higher than the extrapolated rheometry-derived G∗ at 60 Hz, but the strain dependence was consistent between rheometry and MR elastography measurements. ConclusionsThis study demonstrates that MR elastography can detect changes in ex vivo bovine liver complex shear modulus due to either uniform or focal preload and therefore can be a useful technique to characterize nonlinear viscoelastic properties of soft tissue, provided that strains applied to the tissue can be quantified. Although MR elastography could reliably characterize the strain dependence of the ex vivo bovine liver, MR elastography overestimated the complex shear modulus of the tissue compared to rheological measurements, particularly at lower preload (<10%). That is likely to be important in clinical hepatic MR elastography diagnosis studies if preload is not carefully considered. A limitation is the absence of overlapping frequency between rheometry and MR elastography for formal validation.

Identification of a Green Algal Strain Collected from the Sarno River Mouth (Gulf of Naples, Italy) and Its Exploitation for Heavy Metal Remediation.

Heavy metals (HMs) can induce both chronic and acute harmful effects on marine and freshwater biota. The environmental impact of HMs in freshwater, seawater, soil, and wastewater can be limited using microbes, including microalgae, that are able to remove metals from environmental matrices. Indeed, they can passively adsorb and actively accumulate these persistent pollutants within their organelles, limiting their detrimental effects on cellular metabolism. The Sarno River is a 30 km long freshwater stream located in Southern Italy, polluted by partially untreated municipal, agricultural, and industrial wastewaters. In spite of this, microalgal cultures from Sarno River or Sarno River Mouth have never been established. In the present study, we isolated a green algal strain from the Sarno River Mouth and determined its ability to grow in polluted seawater containing different concentrations of cadmium, lead, or zinc. This strain was found to be able to accumulate these elements within its biomass in a dose-dependent manner. Growth inhibition experiments confirm the relatively low toxicity of Cd and Pb below 50 µM, while algal growth was seriously affected in Zn-amended media. To the best of our knowledge, this is the first study focused on the ability of microalgae from Sarno River Mouth to tolerate and uptake HMs.

Antitumor and antimicrobial activity of fatty acids from green microalga Coelastrella sp. BGV

Green microalgae are a valuable source of biologically active substances with antitumor and antimicrobial effects. Coelastrella sp. BGV is a strain of green microalga isolated in Bulgaria. The aim of the study was to analyze the fatty acid profile of Coelastrella sp. BGV and to assess the antitumor and antimicrobial activities of the extracted free fatty acids. The fatty acid content of a total lipid extract from the green microalga Coelastrella sp. BGV was determined by gas chromatography mass spectrometry. The antitumor activity of FAs against human HeLa tumor cells was estimated by MTT testing and fluorescence microscopy methods. The antimicrobial activity of FAs against Gram-positive, Gram-negative bacteria and the fungal pathogen Candida albicans was studied by the disk diffusion and microdilution methods. Eleven fatty acids were identified in the lipid extract of Coelastrella sp. BGV, of which the monounsaturated oleic acid (18:1) was present in the largest amount - 31.7%, followed by the polyunsaturated linoleic acid (18:2) - 25.9% and saturated palmitic acid (16:0) - 19.2%. The ratio of total unsaturated to saturated fatty acids was 3:1, and the monounsaturated to polyunsaturated fatty acid ratio was 1:1. The extracted FAs showed statistically significant antiproliferative activity against HeLa tumor cells and induced morphological changes in the cell and nucleus characteristic of early and/or late apoptosis. FAs showed varying degrees of antibacterial and antifungal activity against Gram-positive, Gram-negative pathogens and C. albicans . The results obtained are promising in terms of the therapeutic potential of FAs from Coelastrella sp. BGV against tumor cells and against Gram-negative bacteria ( Escherichia coli UPEC, Pseudomonas aeruginosa, Klebsiella pneumoniae ) and the fungal pathogen Candida albicans . • The fatty acid profile of green microalga strain Coelastrella sp. BGV was analyzed. • The antitumor and antimicrobial effects of the isolated fatty acids was assessed. • The lipid extract had a high content of unsaturated fatty acids. • The fatty acids inhibited the growth of HeLa tumor cells and induced apoptosis. • The fatty acids had antimicrobial and antifungal activity.

An adaptive triangular element of absolute nodal coordinate formulation for thin plates and membranes

An adaptive triangular element based on the absolute nodal coordinate formulation is developed for thin plates and membranes in this work. An elegant theory for thin plate and membrane is first generated under the Kirchhoff–Love assumptions, where the Green strain tensor is decomposed into membrane strain and bending strain tensors. The Hsieh–Clough–Tocher triangular element is extended into the frame of the absolute nodal coordinate formulation for the first time and corresponding shape functions are then derived. The elastic force and Jacobian matrix of the membrane element are explicitly derived by the multiplication of constant tensors and generalized coordinates, resulting in higher efficiency than the plate element. The same group of generalized coordinates is used in membrane and plate elements. Based on this characteristic, a novel adaptive algorithm is proposed based on the stress states to determine at which Gauss points only the membrane strain needs to be considered. The accuracy and adaptability are validated using several benchmark problems. The present adaptive element can improve efficiency without loss of accuracy in cases where most of the membrane is fully tensioned and a part of the local region is slack or wrinkled.

Influence of contaminant-spiked polyethylene-type microplastics on the growth and primary production of the freshwater phytoplankton species Scenedesmus armatus and Microcystis aeruginosa

Microplastic pollution and its ecological impact on the aquatic environment are a current focus of research in the scientific community. These microplastics may adsorb contaminants discharged into the aquatic environment, thereby serving as a sink and source for the dissemination of these associated chemical contaminants. However, knowledge about the potential risks of microplastics and associated chemical contaminants on aquatic biota, especially on primary freshwater producers, remains to be explored. In this study, the impact of a polyethylene microplastic type (MP) associated with amoxicillin, ibuprofen, sertraline and simazine (OCs) on the cell growth and photosynthetic activity of the green algae Scenedesmus armatus and the cyanobacteria Microcystis aeruginosa was evaluated after 28 days of exposure. The results show that all the organic contaminants and their respective MP-OC complexes induced stress on cell growth after 28 days of exposure, except when the cyanobacterial strain was exposed to amoxicillin and ibuprofen. Similarly, photosynthetic activity was affected by exposure to MP-OC complexes, with the most evident effect on cellular respiration in the cyanobacterial strain and on net photosynthesis in the green algae strain. Additionally, the ability of the M. aeruginosa strain to synthesize microcystin was significantly reduced. These results show that the formation of MP-OC complexes could reduce their adverse effects, although there is wide variability depending on both the type of organic contaminant and the photosynthetic organisms involved, so further studies are needed to better understand the interactions between these aquatic contaminants. • MP-OC complexes induced stress on freshwater phytoplankton cell growth. • Photosynthetic activity was affected by exposure to MP-OC complexes. • Cellular respiration was more impaired in cyanobacteria than in green microalgae. • Net photosynthesis was more affected in green microalgae than in cyanobacteria. • Microcystin synthesis from cyanobacteria was significantly reduced.

Green microalgal strain Chlorella vulgaris isolated from industrial wastewater with remediation capacity

The present work primarily focused on isolation of Chlorella vulgaris from industrial wastewater, and use as an effective feedstock for producing renewable biodiesel. Post isolation, the lipid was extracted from Chlorella vulgaris using Soxhlet’s extraction method; and the extracted lipid was converted into algal oil biodiesel, which was then characterized using GC–MS spectral analysis. From the optimized reaction parameters: reaction temperature (45 °C), methanol/ C. vulgaris bio-oil ratio (4:1), catalyst concentration (300 mg) of synthesized lipase immobilized magnetic nanoparticles, and reaction time (6 h) under continuous stirring, the highest yield of C. vulgaris biodiesel was recorded as 87.6%. Besides, the lipase immobilized nano-bio catalyst used in the production process, was found to be highly efficient for about 5 to 6 cycles without any significant loss in the conversion efficiency. Finally, the evaluated fuel properties of the produced C. vulgaris biodiesel were in good agreement with ASTM D6751 standards. • Chlorella vulgaris was isolated from industrial waste water. • Achieved highest biodiesel conversion of 87.6% from Chlorella vulgaris . • Immobilized nano-biocatalyst was used for 5 to 6 cycles. • Biodiesel met the specifications set by ASTM standards.