Sustainable next-generation color converters from P. harmala seed extracts for solid-state lighting.

Traditional solid-state lighting heavily relies on color converters, which often have a significant environmental footprint. As an alternative, natural materials such as plant extracts could be employed if their low quantum yields (QYs) in liquid and solid states were higher. With this motivation, here, we investigate the optical properties of aqueous P. harmala extract, develop efficient color-converting solids through a cost-effective and environmentally friendly method, and integrate them with light-emitting diodes (LEDs). To achieve high-efficiency solid hosts for P. harmala-based fluorophores, we optically and structurally compare two crystalline and two cellulose-based platforms. Structural analyses reveal that sucrose crystals, cellulose-based cotton, and paper platforms enable a relatively homogeneous distribution of fluorophores compared to KCl crystals. Optical characterization demonstrates that the extracted solution and the extract-embedded paper possess QYs of 75.6% and 44.7%, respectively, whereas the QYs of the cotton, sucrose, and KCl crystals remain below 10%. We demonstrated that the paper host with the highest efficiency causes a blueshift in the P. harmala fluorescence, whereas the cotton host induces a redshift. We attribute this to the passivation of nonradiative transitions related to the structure of the hosts. Subsequently, as a proof-of-concept demonstration, we integrate the as-prepared efficient solids of P. harmala for the first time with a light-emitting diode (LED) chip to produce a color-converting LED. The resulting blue-emitting LED achieves a luminous efficiency of 21.9 lm Welect -1 with CIE color coordinates of (0.139, 0.070). These findings mark a significant step toward the utilization of plant-based fluorescent biomolecules in solid-state lighting, offering promising environmentally friendly organic color conversion solutions for future lighting applications.

Exploring the Personality Characteristics of Rhinoplasty Patients: Perfectionism, Rumination, and Self-Compassion.

OBJECTIVE: This study investigates differences in personality characteristics, including perfectionism, ruminative thinking style, and self-compassion, between individuals who have undergone rhinoplasty and a control group without any history of cosmetic surgery. METHODS: The study included 33 adult patients who underwent rhinoplasty between 2021 and 2023 at Bursa Uludag University Faculty of Medicine Hospital and 33 adult patients who visited our centre for other complaints as a control group. The rhinoplasty group consisted of primary surgical patients with functional and cosmetic concerns, excluding those who sought revision surgery or had only functional problems. The control group consisted of individuals with no prior cosmetic surgery history and no expectations of aesthetic interventions. Psychiatric analysis was performed using Frost multidimensional perfectionism scale, ruminative thinking style questionnaire, and self-compassion scale. RESULTS: This research revealed that individuals who had rhinoplasty scored higher in perfectionism 109.3 (±23.3) and ruminative thinking 87.9 (±22) compared to those who did not undergo surgery 94.15 (±22.2) and 77.7 (±23), respectively. Additionally, the rhinoplasty group had lower self-compassion scores, 80.4 (±17.3), than the control group, 86.1 (±11.2). Statistically significant differences were observed in perfectionism between the groups (p = 0.009). In rhinoplasty patients, a notably positive correlation was found between perfectionism and ruminative thinking scores (r = 0.482; p = 0.005), while a moderately significant negative correlation was observed between self-compassion and ruminative thinking scores (r = - 0.465; p = 0.006). CONCLUSION: Individuals who undergo rhinoplasty generally show increased levels of perfectionism and are more prone to ruminative thinking. They also demonstrate reduced self-compassion compared to non-surgical control groups. Cosmetic surgeons should be aware of these psychological trends and consider using appropriate scales during pre-surgery consultations and follow-up visits. Adopting this informed approach can improve the surgeon-patient relationship and help overcome communication challenges. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Eco-Friendly Intracellular Biosynthesis of CdS Quantum Dots Using Pseudomonas aeruginosa: Evaluation of Antimicrobial Effects and DNA Cleavage Activities.

BACKGROUND: Intracellular biosynthesis of Quantum Dots (QDs) based on microorganisms offers a green alternative and eco-friendly for the production of nanocrystals with superior properties. This study focused on the production of intracellular CdS QDs by stimulating the detoxification metabolism of Pseudomonas aeruginosa. METHODS: For this aim, Pseudomonas aeruginosa ATCC 27853 strain was incubated in a solution of 1mM cadmium sulphate (CdSO4) to manipulate the detoxification mechanism. The intracellularly formed Cd-based material was extracted, and its characterization was carried out by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Energy Dispersive X-ray (EDX) and dynamic light scattering (DLS) analyses and absorption-emission spectra. RESULTS: The obtained material showed absorption peaks at 385 nm and a luminescence peak at 411 nm, and the particle sizes were measured in the range 4.63-17.54 nm. It was determined that the material was sphere-shaped, with a cubic crystalline structure, including Cd and S elements. The antibacterial and antifungal activities of CdS QDs against patent eleven bacterial (four Grampositive and seven Gram-negative) and one fungal strains were investigated by the agar disk diffusion method. It was revealed that the obtained material has antibacterial effects on both Grampositive and Gram-negative bacteria. However, cleavage activity of CdS QDs on pBR322 DNA was not detected. CONCLUSION: As a result, it has been proposed that the stimulation of the detoxification mechanism can be an easy and effective way of producing green and cheap luminescent QDs or nanomaterial.

Cellular Interaction of Human Skin Cells towards Natural Bioink via 3D-Bioprinting Technologies for Chronic Wound: A Comprehensive Review.

Skin substitutes can provide a temporary or permanent treatment option for chronic wounds. The selection of skin substitutes depends on several factors, including the type of wound and its severity. Full-thickness skin grafts (SGs) require a well-vascularised bed and sometimes will lead to contraction and scarring formation. Besides, donor sites for full-thickness skin grafts are very limited if the wound area is big, and it has been proven to have the lowest survival rate compared to thick- and thin-split thickness. Tissue engineering technology has introduced new advanced strategies since the last decades to fabricate the composite scaffold via the 3D-bioprinting approach as a tissue replacement strategy. Considering the current global donor shortage for autologous split-thickness skin graft (ASSG), skin 3D-bioprinting has emerged as a potential alternative to replace the ASSG treatment. The three-dimensional (3D)-bioprinting technique yields scaffold fabrication with the combination of biomaterials and cells to form bioinks. Thus, the essential key factor for success in 3D-bioprinting is selecting and developing suitable bioinks to maintain the mechanisms of cellular activity. This crucial stage is vital to mimic the native extracellular matrix (ECM) for the sustainability of cell viability before tissue regeneration. This comprehensive review outlined the application of the 3D-bioprinting technique to develop skin tissue regeneration. The cell viability of human skin cells, dermal fibroblasts (DFs), and keratinocytes (KCs) during in vitro testing has been further discussed prior to in vivo application. It is essential to ensure the printed tissue/organ constantly allows cellular activities, including cell proliferation rate and migration capacity. Therefore, 3D-bioprinting plays a vital role in developing a complex skin tissue structure for tissue replacement approach in future precision medicine.

Intracellular biosynthesis of PbS quantum dots using Pseudomonas aeruginosa ATCC 27853: evaluation of antibacterial effects and DNA cleavage activities.

Bacterial biosynthesis of quantum dots (QDs) offers a green alternative for the production of nanomaterials with superior properties, such as tunable size dependent emission spectra and a long fluorescence lifetime. In this study, we have achieved intracellular production of PbS QDs using Pseudomonas aeruginosa ATCC 27853. The characterization of these PbS QDS was performed by different techniques, such as Ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and particle size analysis (DLS). The obtained results confirmed the synthesis of PbS QDs. The PbS QDs showed absorption peaks at 1088 nm (ultraviolet-visible spectrometry) and a luminescence peak at 1572 nm. In addition, the intracellular biosynthesized PbS QDs showed a particle size in the range 3.47-11.45 nm, which is consistent with DLS and sphere-shaped nanocrystals with good crystallinity and a cubic cristalline structure including pure Pb and S elements. Biosynthesized PbS QDs showed antibacterial activity against Proteus mirabilis ATCC 25933 and Escherichia coli ATCC 25922 from Gram (-) bacteria and Bacillus cereus NRLL B-3008 and Micrococcus luteus ATCC 10240 from Gram (+) bacteria. Besides, these current results obtained from the cleavage studies revealed that PbS QDs do not show DNA cleavage activity. Consequently, the microorganism-based intracellular method allows an economic and environmentally friendly way to obtain PbS QDs with superior optical properties and they have a potential to be used in healthcare applications.

Biosynthesis of silver nanoparticles using leaf extract of Aesculus hippocastanum (horse chestnut): Evaluation of their antibacterial, antioxidant and drug release system activities.

Biosynthesis of metal nanoparticles is expected as a cost efficient and ecofriendly option in the research study. Therefore, the aqueous extracts made from leaf of Aesculus hippocastanum (horse chestnut) were used as the reducing factors to synthesize silver nanoparticles (AgNPs) and their antioxidant, antibacterial and the application of resveratrol combined AgNPs as efficient delivery vehicles have also been evaluated. The biosynthesized AgNPs were characterized by UV-Visible Spectroscopy, Fourier-Transform Infrared Spectroscopy (FTIR), X Ray Diffraction (XRD), Zeta potential, and Scanning Electron Microscopy (SEM). The AgNPs were found to be stable at -29.1 mV through zeta potential study. According to the UV-Vis measurements, AgNP formation was observed at a wavelength range of 420-470 nm. The Ag NPs were spherical with a size of 50 ±â€¯5 nm. AgNPs exhibited strong antibacterial activity against all tested bacterial species but have no effect against fungal strains. AgNPs showed an important inhibitive activity counter the DPPH radical and thereby indicate a source for antioxidants. The free radical scavenging activity of AgNP was calculated as 54.72% at the highest concentration (100 ppm). The superoxide radical scavenging activity of AgNPs was found to be increased with increasing concentrations and the average inhibition was about 62.9% as compared to the activity of plant extract. In vitro investigations on the drug delivery from AgNPs exhibited pH dependency; the release was significant (45.6%) below acidic terms (pH 5.2) when in proportion to physiological terms (pH7.4). It was observed that the resveratrol-combined to AgNPs stays on the nanoparticle surface for a lengthy time in the plasma at physiological pH (7.4), so very reducing the flank influence on the normal tissues. It can be concluded that horse chestnut leaves has reduction potential as well as being a capping agent to produce well-defined nanoscale silver particles. Our biosynthesized Ag NPs can be used antibacterial, antioxidant agent and also for as effective delivery vehicles in the near future.

An inclusive physicochemical comparison of natural and synthetic chitin films.

Natural and synthetic chitin films, obtained from the same source were produced and their physicochemical properties were examined comparatively. Firstly, natural chitin film was obtained from elytra of an insect (Oryctes nasicornis L.) and purity of the obtained chitin film (degree of acetylation: 79±2%) was demonstrated by solid state 13C nuclear magnetic resonance (13C NMR). Then, the synthetic film was produced by dissolving of natural chitin film in LiCl-DMAc. The obtained natural and synthetic films were characterized by AFM, TGA, DSC, FTIR, mechanical properties, light transmission and contact angle. The analyses result demonstrated that natural chitin film lost very important properties such as high thermal stability, transparency, nanofibrous nature, tensile strength, Young's modulus and hydrophobicity after transforming the synthetic film.

Formation of Matricaria chamomilla extract-incorporated Ag nanoparticles and size-dependent enhanced antimicrobial property.

Various concentrations of Matricaria chamomilla (M. chamomilla) flower extract was used for biosynthesis of Ag NPs with different sizes, 70±5 (Ag NP-1), 52±5 (Ag NP-1) and 37±4nm (Ag NP-3), and size-specific antimicrobial activity of them was evaluated towards Gram+ Staphylococcus aureus (S. aureus), Gram- Escherichia coli (E. coli) bacteria and Candida fungus albicans (C. albicans). We also examine the formation of Ag NPs as a function of the plant extract volume, Ag ion concentration (Ag+) and reaction time. M. chamomilla flower extract at 100ppm shows mild inhibitory effect by inhibiting growth of all target pathogens. The extract mediated Ag NPs even at low concentration (6.25ppm) caused reductions in cell densities of the pathogens. The potential reasons for the highly effective inhibitory activity of the extract mediated Ag NPs are: (1) synergistic effects due to combination of M. chamomile extract and Ag NP because Ag NP is an effective germicidal and M. chamomile plant itself shows mild inhibitory property, (2) high localized concentration of M. chamomile extract due to nano scale entrapment of it on surface of Ag NP and (3) size-specific antibacterial efficacy of Ag NP because small size increases the active surface area of Ag NP, which reacting bacterial cells and increases number of extract molecules anchored on the surface of Ag NP.

Encapsulation of Flurbiprofen by Chitosan Using a Spray-Drying Method with In Vitro Drug Releasing and Molecular Docking.

OBJECTIVES: This study aimed to prepare chitosan-flurbiprofen micro-nano spheres as environmentally friendly for drug releasing by spray-drying method without any cross-linking agent. It was also aimed to reveal the favorable binding geometries of chitosan and flurbiprofen using molecular modeling. MATERIALS AND METHODS: In this study, flurbiprofen was encapsulated with chitosan using spray-drying technique. The used chitosan, flurbiprofen and obtained spheres were characterized via fourier transmission infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), X-ray diffractometer and scanning electron microscopy (SEM). Drug entrapment efficiency was carried out for determination of the drug amount in the micro-nano spheres. In vitro release studies of CS-FP spheres were also examined in the simulated biological fluid at pH 7.4. Encapsulation process of flurbiprofen was combined with the docking studies to investigate the possible binding sites of the chitosan. RESULTS: FT-IR results confirmed that H-bonding system was formed between chitosan and drug. CS-FP spheres with spherical shape were observed by SEM. TGA analysis results showed that thermal stabilities of flurbiprofen and chitosan were decreased after the encapsulation process. The spheres were used for in vitro releasing studies in simulated biological fluids. All these analysis results clearly showed that encapsulation was successfully carried out with 73.28% efficiency. Molecular modeling studies showed that CS-FP stable complexes was formed through a hydrogen bonding system between OH group of the drug molecule and chitosan hydroxyl (OH) group with a binding energy of -3.90 kcal/mol. Our computational results supported to spectroscopic results obtained by FTIR. CONCLUSION: This study proved that micro-nano spheres can be prepared without using cross-linking agent by spray-drying method. The results of the drug releasing studies showed that release of encapsulated flurbiprofen was completed within 48h. The results of docking analysis can be suggested for the design of new drug carrier systems with chitosan.

Crayfish chitosan for microencapsulation of coriander (Coriandrum sativum L.) essential oil.

In this study, chitosan, which was obtained from the waste shells of crayfish (Astacus leptodactylus), was used for the encapsulation of the essential oil isolated from coriander (Coriandrum sativum L.) via the spray drying method. The obtained capsules were characterized using SEM, FT-IR, TGA and XRD. The size of the microcapsules was between 400nm - 7µm. It was determined that the swelling characteristic of the capsules was pH sensitive. The release showed bi-phasic characteristics and the maximum degree was reached after 72h. Antimicrobial activity studies showed that pure chitosan more effective than the capsule. The antioxidant activity was recorded concentration-dependent. In contrast the antimicrobial activity, antioxidant activity of the capsule was found much higher than the oil and the pure chitosan. Consequently, it was determined that this product could be used in the food and pharmaceutical industries as a natural antioxidant and antimicrobial agent.

Chamomile flower extract-directed CuO nanoparticle formation for its antioxidant and DNA cleavage properties.

In this study, we report the synthesis of copper oxide nanoparticles (CuO NPs) using a medicinal plant (Matricaria chamomilla) flower extract as both reducing and capping agent and investigate their antioxidant activity and interaction with plasmid DNA (pBR322).The CuO NPs were characterized using Uv-Vis spectroscopy, FT-IR (Fourier transform infrared spectroscopy), DLS (dynamic light scattering), XRD (X-ray diffraction), EDX (energy-dispersive X-ray) spectroscopy and SEM (scanning electron microscopy). The CuO NPs exhibited nearly mono-distributed and spherical shapes with diameters of 140 nm size. UV-Vis absorption spectrum of CuO NPs gave a broad peak around 285 and 320 nm. The existence of functional groups on the surface of CuO NPs was characterized with FT-IR analysis. XRD pattern showed that the NPs are in the form of a face-centered cubic crystal. Zeta potential value was measured as -20 mV due to the presence of negatively charged functional groups in plant extract. Additionally, we demonstrated concentration-dependent antioxidant activity of CuO NPs and their interaction with plasmid DNA. We assumed that the CuO NPs both cleave and break DNA double helix structure.

Temporal variation of heavy metal accumulation and translocation characteristics of narrow-leaved cattail (Typha angustifolia L.).

The aim of this study was to investigate seasonal heavy metal accumulation and translocation characteristics of the narrow-leaved cattail (Typha angustifolia L.). Sediment and plant samples were taken seasonally from six different locations identified for this purpose, and Pb, Cr, Cu, Ni, Zn, and Cd concentrations as well as accumulation factor (AF) and translocation factor (TF) values were determined. It was noted that the metal concentrations in the plant roots, rhizomes, and leaves differed seasonally. The metals mainly accumulated in the plant roots, and Zn was the element that accumulated the most in the plant roots, rhizomes, and leaves. The highest Zn concentration was observed to be 56.47 µg g(-1) in the rhizome sample from the summer. In all the seasons, the AF value of Cd was observed to be above 1. In addition, the TF value was below 1 for all elements in every season. While the element having lowest uptake and translocation ratio was Cr, and the highest uptake and translocation ratio was found for Cd. The AF and TF values suggest that the plant would be most appropriate for use in phytostabilization.

Characterisation of α-chitin extracted from a lichenised fungus species Xanthoria parietina.

Lichens are symbiotic associations formed mainly by ascomycete fungi and green algae or cyanobacteria. The presence of chitin in the fungal cell wall has been revealed by previous studies. Considering the presence of fungi in the lichens, this work determines the presence of chitin in a cosmopolitan lichen species Xanthoria parietina. In this study, chitin was derived from a lichen species for the first time and its physicochemical properties were determined by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and elemental analysis. The dry weight chitin content of X. parietina was 4.23%, and this chitin was in the α-form. The crystalline index value of the lichen chitin was calculated as 70.1%. The chitin from X. parietina had a smooth surface.

Single and combined effects of exposure concentration and duration on biological responses of Ceratophyllum demersum L. exposed to Cr species.

This study aimed to demonstrate the ways in which two chromium species, Cr (III) and Cr (VI), can affect various physiological and biochemical parameters in the plant Ceratophyllum demersum L., and to evaluate the single and combined impact of exposure concentration and duration. C. demersum was exposed to Cr (III) and Cr (VI) at a variety of concentrations (1, 2, 5, and 10 mM) and for differing durations (1, 2, 4, and 7 days), after which Cr accumulation, relative growth rate (RGR), malondialdehyde (MDA) content, electrical conductivity (EC), photosynthetic pigmentation, proline content and antioxidant enzyme activities were examined. The single and combined effects of exposure duration and Cr concentration on each parameter were determined using a two-way analysis of variance. For both the Cr (III) and Cr (VI) applications, it was observed that concentration had a significant effect on all parameters assessed. However, duration had no statistically significant effect on proline content in the Cr (III) application, or on MDA and protein content in the Cr (VI) application. It was determined that concentration exerted greater effects than duration for both Cr species studied. In addition, the results indicated that duration and concentration had a synergistic effect on variations of RGR, EC, protein content, and antioxidant enzyme activities in both the Cr (III) and Cr (VI) applications. These results may be useful when planning further phytoremediation and plant biotechnology studies.

The quick extraction of chitin from an epizoic crustacean species (Chelonibia patula).

Chitin was isolated from the shells of Chelonibia patula (barnacle, Crustacea), which lives on blue crab epizoically, following a 10-min demineralisation process through HCl and a 20-min deproteinisation process through NaOH. Due to the low-crystalline structure, and mineral-rich and low-protein content of the shells, chitin isolation was convenient. It was observed that the shell structure of C. patula contains 3.11% chitin per its dry weight. Following characterisation of the isolated chitin by using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffractometry, elemental analysis and scanning electron microscopy, it was determined that there was close similarity with the α-chitin isolated from crabs, shrimps and insects in various studies. It was observed that chitin was composed of nanofibres with a width of 10-20 nm. It was concluded that this was an economically advantageous chitin resource compared with crustaceans such as shrimp, crayfish and crab, because it is possible to isolate chitin in a significantly shorter time.

Resting eggs as new biosorbent for preconcentration of trace elements in various samples prior to their determination by FAAS.

In this study, the resting eggs of aquatic creatures living in freshwater (Daphnia, Cladocera, Crustacean) ecosystems were used as a novel biosorbent extractant for synchronous preconcentration of trace Cd(II), Co(II), Cu(II), Mn(II), and Ni(II) previous to measurement by flame atomic absorpiton spectrometry (FAAS). Using column procedures, optimization studies were conducted to realize the effective adsorption of the analyte ions such as the solution pH, amount of the biosorbent, volume of the sample, interfering ions, etc. A high preconcentration factor of 67 and low relative standard deflection of ≤4.1% (n=8) were obtained. The invention constrains based on the 3 s/b criterion were 2.4 for Cd(II), 41.4 for Co(II), 4.2 for Cu(II), 3.0 for Mn(II), and 9.6 µg L(-1) for Ni(II). The accuracy of the method was verified by analysis of a certified standard reference material. The used procedure was applied to the definition of the analytes in diverse environmental samples with convincing results. Consequently, the resting eggs of Daphnia can be used as a biosorbent for preconcentration and biosorption studies.

Temporal variation of metals in water, sediment and tissues of the European chup (Squalius cephalus L.).

The aim of this study was to analyze seasonal variation of levels of Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Lead (Pb) in water, sediment and tissues of Squalius cephalus (L., 1758) taken from five different stations chosen at Yamula Dam Lake (Kayseri, Turkey). Concentrations of metals were generally sorted as water < tissue < sediment. The highest concentration of metals in water was observed in the samples taken in the summer (Mn, 1.04 ± 0.15 mg L(-1); Ni, 0.42 ± 0.12 mg L(-1); Cu, 1.25 ± 0.88 mg L(-1); Zn, 3.61 ± 1.53 mg L(-1); Pb, 0.58 ± 0.09 mg L(-1)). While the highest Zn (24.85 ± 21.82 µg g(-1)) and Pb (10.89 ± 4.2 µg g(-1)) concentrations in sediment were observed in the winter samples, the highest Mn concentration (167.2 ± 99.37 µg g(-1)) was observed in the summer. Cd pollution was determined in sediment according to international criteria. The highest metal concentration in tissues was generally observed in the liver and the other tissues; following liver were gills and muscles. In liver tissues, while the highest accumulation of Zn (110.34 ± 13.1) and Mn (22.5 ± 14.85 µg g(-1)), which are essential for the body, were observed in the winter, Pb (22.58 ± 7.83 µg g(-1)) and Cd (11.77 ± 7.83 µg g(-1)), which are toxic, were found to be higher in the summer. Also, concentrations of Mn, Cd and Pb in muscle tissues were found to be above the limits permitted.

Effects of exogenous glycinebetaine and trehalose on lead accumulation in an aquatic plant (Lemna gibba L.).

This study was aimed at investigating and comparing the effects of exogenous glycinebetaine (GB) and trehalose (TR) on lead (Pb) accumulation in Lemna gibba. Two-way ANOVA showed that both GB and TR had significant effects on Pb accumulation. However, TR seemed to be more effective than GB. It was determined that 5 mM GB application decreased Pb accumulation whereas 0.5 mM TR increased and 2 and 5 mM decreased Pb accumulation. The results obtained from this study will be useful for examining the phytoremediation of polluted water using aquatic plants.

Nickel accumulation and its effect on biomass, protein content and antioxidative enzymes in roots and leaves of watercress (Nasturtium officinale R. Br.).

In order to understand its response towards nickel stress, watercress (Nasturtium officinale R. Br.) was exposed to nickel (1-25 mg/L) for 1, 3, 5 and 7 days. The accumulation and translocation of nickel were determined and the influence of nickel on biomass, protein content and enzymatic antioxidants was examined for both roots and leaves. It was determined that N. officinale could accumulate appreciable amounts of Ni in both roots and leaves. Nickel accumulated particularly in the roots of plants. Biomass increased at low nickel concentrations but certain measurable change was not found at high concentrations. Under stress conditions the antioxidant enzymes were up-regulated compared to control. An increase in protein content and enzyme activities was observed at moderate exposure conditions followed by a decline at both roots and leaves. The maximum enzyme activities were observed at different exposure conditions. Our results showed that N. officinale had the capacity to overcome nickel-induced stress especially at moderate nickel exposure. Therefore, N. officinale may be used as a phytoremediator in moderately polluted aquatic ecosystems.

Biological responses of duckweed (Lemna minor L.) exposed to the inorganic arsenic species As(III) and As(V): effects of concentration and duration of exposure.

The accumulation of arsenic (As) and physiological responses of Lemna minor L. under different concentration (0, 1, 4, 16 and 64 microM) and duration (1, 2, 4 and 6 days) of two species As, NaAsO(2) and Na(2)HAsO(4).7H(2)O, were studied in hydroponics. The accumulation of both As species depended on As concentration and exposure duration. The highest accumulation of As was found as 17408 and 8674 microg g(-1), for plants exposed to 64 microM of As(III) and As(V), respectively, after 6 days. Two-way ANOVA analyses indicated that, for plants exposed to arsenite (As(III)), exposure duration had a greater effect than concentration on As accumulation. Conversely, exposure concentration had a greater effect on As accumulation in plants exposed to arsenate (As(V)). Arsenic exposure levels, approaching 16 microM for As(III) and 64 microM for As(V), did not significantly affect EC values. Beyond these exposure concentrations, EC values increased in a manner that depended on duration. Significant effect of As(III) on lipid peroxidation was observed at 1 microM application whereas, this effect started to be significant after an exposure to 16 microM As(V). For both As(III) and As(V), photosynthetic pigment levels slightly increased for the first day with respect to the control, followed by a gradual decline at higher concentrations and durations. An increase in protein content and enzyme activity was observed at moderate exposure conditions, followed by a decrease. Significant positive correlations were determined between accumulated As and ion leakage and lipid peroxidation. Negative correlations were found between accumulated As and total chlorophyll and protein content. Our results suggested that exposure duration and concentration had a strong synergetic effect on antioxidant enzyme activity. The findings of the present study may be useful when this plant is used as a phytoremediator in arsenic-polluted water.