Concentrations Of CuSO4 Research Articles

Sub-lethal effects of waterborne copper in early developmental stages of rainbow trout (Oncorhynchus mykiss)

The aim of this work was to study the impact of copper during a sub-chronic exposure to environmental concentrations in the early life stages of rainbow trout (Oncorhynchus mykiss). Eyed-stage embryos of rainbow trout, at 265 °D, were exposed in semi-static conditions to sub-lethal concentrations of CuSO4 up to the larval stage (528 °D) under laboratory-controlled conditions. During 3 weeks, they were exposed to the environmentally-realistic concentration of 2 µg/L Cu and to a 10-fold higher concentration, 20 µg/L Cu. Several biological (survival, hatching success, malformation, growth) and behavioral (swimming activity) and molecular endpoints (genotoxicity and gene transcription) were studied. Exposure to 20 µg/L Cu had an inhibitory effect on hatching and increased half-hatched embryos (25%). At the end of the exposure, no significant differences were observed in growth of the larvae exposed to the highest Cu concentration. However, larvae exposed to 2 µg/L Cu exhibited increased growth in comparison with non-exposed larvae. The percentage of malformed larvae was significantly higher for both copper conditions, with skeletal malformations being the most observed. Expression of several genes was evaluated in whole larvae using quantitative real-time PCR. Genes involved in detoxification (gst, mt1 and mt2) and in cell cycle arrest (p53) were significantly repressed in both copper conditions when compared to control. In addition, potential genotoxic effects on larvae were investigated by the comet assay on blood cells, but this test did not demonstrate any significant DNA damage on larvae exposed to copper. This study confirms the adverse effects of copper on early life stages of rainbow trout even at the lowest environmentally relevant tested concentration.

Effects of soluble copper and copper oxide nanoparticle exposure on the immune system of mussels, Mytilus galloprovincialis.

Copper and copper oxide nanomaterials (nCuO) can enter the marine environment negatively impacting mussels, an environmental and commercially relevant organism. We analyzed the effects on the immune system of adult mussels exposed to soluble copper (CuSO4 , 20-50 μg/L) or nCuO (100-450 μg/L). CuSO4 caused significant copper accumulation in gills and cell-free hemolymph, while nCuO caused cell damage to gills and significant copper accumulation in hemocytes, the most abundant cells in the hemolymph. Both sources of copper caused cellular toxicity in hemocytes by increasing reactive oxygen species production and lysosome abundance, and decreasing multi-drug resistance transporter activity. Though hemocyte abundance was not affected, their in-vitro phagocytic activity decreased, explaining the slight (but not statistically significant) increase in bacterial proliferation in mussels exposed to the pathogenic bacteria Vibrio tubiashii following copper exposure. Thus, exposure to non-lethal concentrations of CuSO4 or nCuO can potentially increase mussel susceptibility to bacterial infections.

Capillary-tube package devices for the quantitative performance evaluation of nuclear magnetic resonance spectrometers and pulse sequences.

With the increased sensitivity of modern nuclear magnetic resonance (NMR) spectrometers, the minimum amount needed for chemical-shift referencing of NMR spectra has decreased to a point where a few microliters can be sufficient to observe a reference signal. The reduction in the amount of required reference material is the basis for the NMR Capillary-tube Package (CapPack) platform that utilizes capillary tubes with inner diameters smaller than 150 µm as NMR-tube inserts for external reference standards. It is shown how commercially available electrophoresis capillary tubes with outer diameters of 360 µm are filled with reference liquids or solutions and then permanently sealed by the arc discharge plasma of a commercially available fusion splicer normally employed for joining optical fibers. The permanently sealed capillaries can be used as external references for chemical-shift, signal-to-noise, resolution, and concentration calibration. Combining a number of permanently sealed capillaries to form CapPack devices leads to additional applications such as performance evaluation of NMR spectrometers and NMR pulse sequences. A 10-capillary-tube side-by-side Gradient CapPack device is used in combination with one or two constant gradients, produced by room-temperature shim coils, to monitor the excitation profiles of shaped pulses. One example illustrates the performance of hyperbolic secant (sech) pulses in the EXponentially Converging Eradication Pulse Train (EXCEPT) solvent suppression sequence. The excitation profile of the pulse sequence is obtained in a single gradient NMR experiment. A clustered T 1 CapPack device is introduced consisting of a coaxial NMR-tube insert that holds seven capillary tubes filled with aqueous solutions of different concentrations of the paramagnetic relaxation agent copper(ii) sulfate (CuSO4). The different CuSO4 concentrations lead to spin-lattice relaxation times in the seven capillary tubes that cover a range which extends to more than an order of magnitude. Clustered T 1 CapPack devices are best suited to quantify the effects that relaxation has on magnetizations and coherences during the execution of NMR experiments, which is demonstrated for the order-of-magnitude T 1 insensitivity of signal suppression with EXCEPT.

Using response surface methodology optimize culture conditions for human lactoferrin production in desert Chlorella

To optimize the expression conditions for human lactoferrin production, we have constructed the transgenic chlorella with human lactoferrin named as GTD8A1-HLF, the original chlorella was separated from Gurbantunggut Desert in Xinjiang China. To further improve the production of human lactoferrin, a sequential methodology was used to optimize human lactoferrin production by GTD8A1-HLF. First, a screening trial using a Plackett-Burman design was done, and variables with statistically significant effects on human lactoferrin bio-production were identified. These were further optimized by central composite design experiments and response surface methodology. Finally, we found that the maximum human lactoferrin production (52.70 mg/L) was achieved under the following optimized conditions: Initial pH 5.0, NaNO3 concentration of 0.600 mol/L, FeSO4 concentration of 0.006 mol/L, and a CuSO4 concentration of 0.002 mol/L, with the other medium components constituting the basal culture medium BBM. The yield of HLF protein under optimized culture conditions was approximately 4-fold higher than that obtained by using the basal culture medium BBM. The findings are significant for the potential industrial use of GTD8A1-HLF.

Negative effect of copper nanoparticles on the conjugation frequency of conjugative catabolic plasmids

Due to their antimicrobial properties, copper nanoparticles (CuNPs) have been proposed to be used in agriculture for pest control. Pesticides removal is mainly done by microorganisms, whose genes usually are found in conjugative catabolic plasmids (CCP). The aim of this work was to evaluate if CuNPs at subinhibitory concentrations modify the conjugation frequency (CF) of two CCP (pJP4 and pADP1). CuNPs were characterized by scanning electron microscopy with an X-ray detector, dynamic light scattering and X-ray diffraction. Mating assays were done in LB broth supplemented with CuNPs (10, 20, 50 and 100 µg mL−1) or equivalent concentrations of CuSO4. Interestingly, we observed that in LB, Cu+2 release from CuNPs is fast as evaluated by atomic absorption spectrophotometry. Donor and recipient strains were able to grow in all copper concentrations assayed, but CF of mating pairs was reduced to 10% in the presence of copper at 20 or 50 µg Cu mL−1 compared to control. Thus, our results indicated that both copper forms, CuNPs or CuSO4, negatively affected the transfer of catabolic plasmids by conjugation. Since dissemination of degradative genes by conjugation contribute to degradation of pesticides by microorganisms, this work improves our understanding of the risks of using copper in agriculture soils, which could affect the biodegradative potential of microbial communities.

Redox dyshomeostasis in the experimental chronic hepatic overloads with iron or copper

Male rats of 80–90 g were overloaded with either Fe(II) or Cu(II) for 42 days by high concentrations of FeCl2 or CuSO4 in the drinking water. The animals were fed with a commercial rodent diet of 2780 kcal/100 g. Both metal treatments led to a liver redox imbalance and dyshomeostasis with oxidative stress and damage and the concomitant enhancement of oxidative processes as indicated by in vivo surface liver chemiluminescence, the sensitive and organ non-invasive assay for oxidative free radical reactions, and by ex vivo determined processes of phospholipid peroxidation and protein oxidation. In parallel, marked decreases in the antioxidant defense were observed. Liver reduced glutathione (GSH) content and the reduced/oxidized glutathione ratio (GSH/GSSG) were early indicators of oxidative metabolic disturbance upon the metal overloads. Thus, GSH plays a central role in the defense reactions involved in the chronic toxicity of Fe and Cu. Chronic overloads of Fe or Cu in rats afford an experimental animal model of hemochromatosis and of Wilson's disease, respectively. These two animal models could be useful in the study and development of the beneficial effects of pharmacological interventions in the two human diseases.

Exogenous Melatonin Protects Canola Plants from Toxicity of Excessive Copper

Physiological mechanisms of canola (Brassica napus L., cv. Westar) plant protection afforded by melatonin (at 0.1–100 μM) from copper salts (at 10–100 μM) were studied. Plants were cultivated on Hoagland–Snyder medium. At the age of 5 weeks, they were subjected to melatonin, copper sulfate, or their combination for 7 days. It was found that excessive copper in a nutrient medium inhibited the dry biomass accumulation against the control by 25–85%. Copper sulfate diminished the content of chlorophylls and carotenoids and functional activity of the thylakoid membranes in the chloroplasts. It increased 2.0–2.5 times the lipid peroxidation (LPO) intensity and the proline level up to 20 times. Melatonin reduced the changes caused by copper, and the degree of the protection depended on melatonin and CuSO4 concentrations. It was found that melatonin decreased the oxidative stress and proline accumulation, both induced by CuSO4. At first, we established the positive correlation (with the coefficient 0.8240) between the level of oxidative stress and proline content in the presence of CuSO4. Possible mechanisms of protection by melatonin and its biological role under conditions of technogenic stress are discussed.

Copper nanoparticles elevate regeneration capacity of (Ocimum basilicum L.) plant via somatic embryogenesis

The current work, was conducted to investigate the influences of copper nanoparticles (Cu-NPs) compared to copper sulfate on plant regeneration of Ocimum basilicum through somatic embryogenesis. To achieve this goal, the Cu-NPs with a size range of (20–40 nm) were chemically synthesized and characterized by the spectrophotometer and the Transmission Electron Microscope (TEM). Thereafter, various concentrations (0.1, 2.5, 5, 7.5, 10, 12.5 and 15 µM) of Cu-NPs or CuSO4·5H2O were added to the culture media. The results proved that the inclusion of Cu-NPs (5 µM) significantly increased the percentage of explants produced somatic embryos (from 15 to 84%) and the average number of regenerated plantlets/explant (from 4.3 to 18.7) in comparison to the control treatment (0.1 µM CuSO4·5H2O). In addition, the results evidently proved that the use of copper in the crystalline form as Cu-NPs is superior to the ionic form as CuSO4·5H2O. Thus the use of Cu-NPs (5 µM) increased the percentage of explants produced somatic embryos from (36–84%) and the average number of regenerated plantlets/explant (from 7.4 to 18.7) compared to CuSO4·5H2O (5 µM). Finally, the elevated regeneration capacity of basil plant via somatic embryogenesis proved that an efficient protocol was achieved in this study as a promising step in the field of plant nanobiotechnology.

Production of CuO nanoparticles using a simple precipitation method in a rotating packed bed with blade packings

CuO nanoparticles were produced using a simple precipitation method in a rotating packed bed with blade packings in continuous mode. The reactant and precipitant were CuSO4 and Na2CO3, respectively. The effects of the rotational speed, the flow rates of aqueous CuSO4 and Na2CO3, and the concentrations of CuSO4 and Na2CO3 on the size of the produced CuO nanoparticles were studied. The results thus obtained indicate that a lower rotational speed and smaller flow rates of aqueous CuSO4 and Na2CO3 yielded smaller CuO nanoparticles. However, increasing concentrations of CuSO4 and Na2CO reduced the size of the produced CuO nanoparticles. The smallest CuO nanoparticles, which had an average size of 54 nm, were produced at a rotational speed of 600 rpm, flow rates of aqueous CuSO4 and Na2CO3 of 0.3 L/min, a CuSO4 concentration of 0.3 mol/L, and an Na2CO3 concentration of 0.3 mol/L. The catalytic activity of the smallest CuO nanoparticles was evaluated by using them to degrade methylene blue with H2O2. CuO nanoparticles effectively activated H2O2 and so degraded methylene blue with an efficiency of 62% in 90 min.

Unexpected fluctuations of trace element levels in cell culture medium in vitro: caveat emptor.

Copper is an essential trace element micronutrient in human and animal nutrition. Trace amounts present even in ultrapure water, serum and other cell culture medium components are sufficient to support the health requirements of most cell types in culture. Analysis of a variety of different types of basal media from a number of different suppliers revealed large fluctuations in the levels of copper, and also of other micronutrients including zinc, iron, selenium and cobalt. Investigations on proliferating Caco-2 cells revealed reductions in growth with increasing copper concentrations within the range seen in the commercial media and changes in expression of apoptosis- and autophagy-related proteins were noted. Even at concentrations of 1μM CuSO4 where there was no significant change in cell growth, there was a significant decrease in procaspase-3 expression. These results stress the importance of batch testing of basal media when undertaking trace metal research since the baseline levels may vary. Batch variation of serum is well established but our results suggest that batch variation of the media may also be important.

Application of ligninolytic enzyme of Lentinus polychrous on synthetic dye decolorization

Contamination of water resources by synthetic dyes causes many environmental and health problems. Fungal ligninolytic enzymes have been applied for dye decolorization due to its ability in degrading a wide variety of recalcitrant substances. Extracellular ligninolytic enzyme production by white rot fungus, Lentinus polychrous, grown in glucose containing medium supplemented with rice straw powder and soybean pomace was monitored. Optimum condition for remazol brilliant blue R (RBBR) decolorization was studied by varying initial RBBR concentrations, pH values, and initial crude enzyme concentrations. The result revealed that the ligninolytic enzyme dominantly produced was laccase with an activity of 0.095 U/ml on day 15, and a small amount of manganese peroxidase was also detected. The crude laccase produced from L. polychrous, effectively decolorized the dye within a short period of time, that was approximately 50% of 20 mg/l RBBR was decolorized within the first 2 hours. The optimal pH for RBBR decolorization was 3.0 which had an efficiency of 87% within 6 hours after incubation. Moreover, the best redox mediator of laccase was CuSO4, whose decolorization efficiency was over twice than that of samples without this mediator. The decolorization intensified with increase of CuSO4 concentration but higher concentrations of chromium tended to suppress decolorization.

Rabies virus glycoprotein ectodomain expressed in Drosophila Expression System (Drosophila melanogaster Schneider 2)

Background: Rabies is a viral neglected disease considered fatal, that affects mammals and with only 12 cases of survival reported in humans. Despite the existence of preventive vaccines, rabies still represents a serious public health problem, with a major impact in vulnerable populations around the world, causing about 55,000 human deaths per year. The membrane glycoprotein of the rabies virus (RVGP), specifically the ectodomain portion, has been intensively studied for the development of recombinant proteins, due to its ability to interact with neutralizing antibodies and induce immune responses. This project aims to construct a plasmidial vector containing only the ectodomain portion and detect the soluble RVGP expressed by recombinant Drosophila. Methods & Materials: The gene encoding ectodomain was synthesized in pUC57 (pRVGPecto) and subcloned into pMtBipV5HisC using EcoRI and NotI enzymes. Products of pMtBip-RVGPecto constructions were screened after DH5a transformation. Then plasmid constructed was transfected into S2cells using Lipofectamine® 2000 to obtain the recombinant stable lineage (S2MTBip_RVGP-ecto). Schott flasks were inoculated with 1 × 105 cells/ml of recombinant population. Cultures were induced at different concentrations of CuSO4 and sampled at different times. Protein detection was done by qualitative Dot and Western blotting analysis using mouse anti-rabies virus Glycoprotein Antibody (LS-C75309) non-conformational monoclonal antibody. Results: Transformation of pMtBip-RVGPecto into DH5a generated two colonies. After mini preparation, those samples had a banding pattern analyzed by enzyme digestion, confirming the presence of ectodomain insert. Recombinant cell population (S2MTBip_RVGP-Ecto) was capable to express rabies virus glycoprotein in soluble form under different induction and sampling conditions, although, part of RVGP is still detected into the cells. The highest RVGP expressions were observed for cultures induced with 0.7 mM (24, 48 and 72 hours), 0.5 mM and 1 mM (24 hours). Western Blotting results showed the presence of a band corresponding to a molecular mass of approximately 50 kDa in culture media, that correspond with expected value since the recombinant protein does not present complete RVGP. Conclusion: It is possible to produce a membrane-independent RVGP using an insect cells expression system (Drosophila melanogaster Schneider 2) contributing to the advancement expected in the vaccine production process.

Interactive effects of temperature and copper toxicity on photosynthetic efficiency and metabolic plasticity in Scenedesmus quadricauda (Chlorophyceae)

Warming and copper (Cu) toxicity are two key abiotic stressors that strongly affect cell growth, photosynthetic rate, and metabolism in microalgae. In this study, a freshwater chlorophyte, Scenedesmus quadricauda, was exposed to various concentrations of copper sulfate (300, 600, and 1000 μM nominal concentrations of CuSO4·5H2O) at 25 and 35 °C. The changes in cell density, photosynthetic parameters, in vivo absorption spectra, reactive oxygen species (ROS) levels, and metabolic profile were analyzed. The effects of copper toxicity on the physiology and biochemistry of microalgae were highly dependent on water temperature. The interactive effects of both stressors induced significant impact on the photosynthetic parameters such as maximum quantum yield (Fv/Fm), saturation irradiance (Ek), and non-photochemical quenching (NPQ). Temperature induced significant impact on cell density, Ek and NPQ, while the Cu toxicity significantly affected the Fv/Fm and NPQ. Changes in the in vivo absorption spectra and high levels of reactive oxygen species (ROS) were observed across different treatments. Overall, S. quadricauda adapted to the two abiotic stresses via NPQ and metabolic restructuring. Key metabolites including glycine, proline, hexadecanoic acid, propanoic acid, octadecanoic acid, galactose, lactose, and sucrose were involved in the microalgal response. The synergistic effects of temperature and Cu stresses on microalgae might affect community tolerance and species distribution in the long run.

Preparation of cupric sulfate-based self-emulsifiable nanocomposites and their application to the photothermal therapy of colon adenocarcinoma

Nanocomposites (NCs) of cupric sulfate monohydrate (CuSO4) were fabricated by hot-melt extrusion (HME) system equipped with twin screws. Micron-sized bulk powder of CuSO4 was dispersed in the mixture of surfactants (Span 80 and Tween 80) and hydrophilic polymer (polyethylene glycol (PEG) 6000) by HME process. Reduction of surface tension by surfactants and homogeneous dispersion in hydrophilic polymer along with HME technique were introduced to prepare CuSO4 NCs. Dispersion of CuSO4 NCs exhibited approximately 204 nm hydrodynamic size, unimodal size distribution, and positive zeta potential values. Encapsulation of CuSO4 in CuSO4 NCs and the physicochemical interactions between CuSO4 and pharmaceutical excipients were investigated by solid-state studies. Of note, CuSO4 NCs group exhibited higher antiproliferation efficacies, compared with bulk CuSO4, in Caco-2 (human adenocarcinoma) cells at 75 and 100 μg/mL CuSO4 concentrations (p < 0.05). Also, near-infrared laser irradiation to CuSO4 NCs group elevated the antiproliferation efficacies, compared with non-irradiation group, in Caco-2 cells. After intravenous injection in mice, CuSO4 NCs did not show severe in vivo toxicities. Developed CuSO4 NCs can be one of promising candidates of photothermal therapeutic agents for colon cancers.

Photosynthetic and biochemical responses of the freshwater green algae Closterium ehrenbergii Meneghini (Conjugatophyceae) exposed to the metal coppers and its implication for toxicity testing.

The freshwater green algae Closterium is sensitive to water quality, and hence has been suggested as ideal organisms for toxicity testing. In the present study, we evaluated the photosynthetic and biochemical responses of C. ehrenbergii to the common contaminants, coppers. The 72 h median effective concentrations (EC50) of CuSO4 and CuCl2 on the test organism were calculated to be 0.202 mg/L and 0.245 mg/L, respectively. Exposure to both coppers considerably decreased pigment levels and photosynthetic efficiency, while inducing the generation of reactive oxygen species (ROS) in cells with increased exposure time. Moreover, the coppers significantly increased the levels of lipid peroxidation and superoxide dismutase (SOD) activity, even at relatively lower concentrations. These suggest that copper contaminants may exert deleterious effects on the photosynthesis and cellular oxidative stress of C. ehrenbergii, representing its powerful potential in aquatic toxicity assessments.

Toxicological effects and behavioural and biochemical responses of Oreochromis mossambicus gills and its cholinesterase to copper: a biomarker application

Gills are both morphologically and physiologically complex whereby they perform several functions such as gas exchange, ion and water exchange, acid base balance, nitrogenous waste excretion, and other metabolic transformations. They are one of the first fish organs to be exposed to heavy metals in the aquatic environment. The exposure of Oreochromis mossambicus to copper showed deleterious effects to normal fish behaviours and varying degrees of gill damage when visualized under inverted light microscopy (stained with haematoxylin–eosin), scanning electron microscopy, and transmission electron microscopy. Abnormalities of the nucleus shape, swollen cells, lipid droplet deposition, and an increase in vacuolation on the affected gills were observed with the degree of damage associated with CuSO4 exposure concentration. CuSO4 exposure in O. mossambicus also gave various patterns of inhibitory effects on cholinesterase (ChE) depending on the concentration of exposure and the organs exposed. Copper exposure altered ChE activity extracted from the gills of O. mossambicus with 99.9% of inhibition at the highest exposure concentration of CuSO4 (20 mg/L). Hence, this study suggests the potential of this fish to become a sentinel species that permits the detection of lower copper contamination levels.

A novel CoCuP electrodeposited film with improved planar hard magnetic properties and film quality

We designed to add Cu into Co-P hard magnetic films prepared via electroplating. The purpose was to make use of immiscibility between Co and Cu, hoping that Cu will segregate at Co-grain-boundaries to mediate magnetic decoupling. Copper is found very difficult to co-electrodeposit with Co due to the large difference in the reduction potentials. A slight variation of CuSO4 concentration in the electrolyte from 1 mM to 2 mM results in a big difference of Cu content from 3.8 wt% to 13 wt% in CoCuP films. However, the CoCuP films are amazingly crack-free up to a thickness no less than 6 μm. The films electroplated with CuSO4 concentration 1.3 mM at pH 4.7 and 25 °C have a Cu content 5.5 wt%, P content 3.1 wt% and exhibit the best magnetic properties. The in-plane magnetic properties are Hc 360 Oe, Br 7450 G, and (BH)m 1.21 MGOe. The perpendicular ones are Hc 800 Oe, Br 1600 G, and (BH)m 0.35 MGOe. The evolution in film composition, microstructure and crystal structure well explains the variation in resultant magnetic properties. These films are readily applicable in mini- and micro-devices which need in-plane magnetic performance.

Gradient filling of copper in porous silicon using a non-contact electrochemical method

In this study, gradient bottom up filling of Cu in porous silicon substrates has been demonstrated using a non-contact electrochemical method. A radially symmetric current that gradually varied across the radius of the sample area was achieved using a modified cell design, which resulted in gradient filling of the vias. Effect of different deposition parameters such as applied current density, copper sulfate concentration and etching to deposition area ratio has been examined and discussed. Increasing the current density from 10 to 15 mA/cm2 resulted in bottom up deposition with less sharp gradients. Further, the study on the effect of copper sulfate concentration highlighted the importance of mass transfer in this process, as either bottom-up deposition or gradient filling could not be achieved at lower CuSO4 concentration (0.1 and 0.25 M). Interestingly, the filling gradient of deposited Cu was obtained with etching to deposition area ratio of 1.6 and 2.7, while a more uniform deposition was observed when the ratio was increased to 3.8. This suggested that the gradient filling may only be accomplished within a certain range of the etching to deposition area ratios.

Sericin–copper-functionalized silk fabrics for enhanced ultraviolet protection and antibacterial properties using response surface methodology

This study investigated the enhancement of the ultraviolet (UV) protection and antibacterial properties of functionalized silk fabrics using a simple, inexpensive and environmental friendly approach. We demonstrated the in situ synthesis of copper nanoparticles (CuNPs) in a silk sericin (SS) matrix, using ascorbic acid as both a reducing agent and antioxidant. Development and optimization was achieved using a central composite design (CCD) in conjunction with the response surface methodology (RSM). The goal was to identify the concentrations of CuSO4 and SS that produced the optimal balance between UV protection and antibacterial activity, when tested against Escherichia coli and Staphylococcus aureus. The SS-CuNP bio-nanocomposites were characterized using scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Statistical analyses indicated that an empirical second-order polynomial could accurately describe the UV protective factor, % reduction of S. aureus and % reduction of E. coli. The three-dimensional response surface graphs showed that the optimal concentrations of CuSO4 and SS were 2380 and 9500 ppm, respectively. To confirm that the levels identified using RSM were optimal in practice, performance evaluations were conducted. These investigated the durability and stability of UV protection and antibacterial activity after repeated washing cycles. The results suggest that these bio-nanocomposites have great potential for the multifunctionalization of silk fibers.

Ferric Sulfate and Proline Enhance Heavy-Metal Tolerance of Halophilic/Halotolerant Soil Microorganisms and Their Bioremediation Potential for Spilled-Oil Under Multiple Stresses.

The aim of this study was to explore the heavy-metal resistance and hydrocarbonoclastic potential of microorganisms in a hypersaline soil. For this, hydrocarbonoclastic microorganisms were counted on a mineral medium with oil vapor as a sole carbon source in the presence of increasing concentrations of ZnSO4, HgCl2, CdSO4, PbNO3, CuSO4, and Na2HAsO4. The colony-forming units counted decreased in number from about 150 g-1 on the heavy-metal-free medium to zero units on media with 40–100 mg l-1 of HgCl2, CdSO4, PbNO3, or Na2HAsO4. On media with CuSO4 or ZnSO4 on the other hand, numbers increased first reaching maxima on media with 50 mg l-1 CuSO4 and 90 mg l-1 ZnSO4. Higher concentrations reduced the numbers, which however, still remained considerable. Pure microbial isolates in cultures tolerated 200–1600 mg l-1 of HgCl2, CdSO4, PbNO3, CuSO4, and Na2HAsO4 in the absence of crude oil. In the presence of oil vapor, the isolates tolerated much lower concentrations of the heavy metals, only 10–80 mg l-1. The addition of 10 Fe2(SO4)3 and 200 mg l-1 proline (by up to two- to threefold) enhanced the tolerance of several isolates to heavy metals, and consequently their potential for oil biodegradation in their presence. The results are useful in designing bioremediation technologies for oil spilled in hypersaline areas.