Effect of titanium oxide/reduced graphene (TiO2/rGO) addition onto water flux and reverse salt diffusion thin-film nanocomposite forward osmosis membranes.

Thin-film nanocomposite (TFN) forward osmosis (FO) membranes have attracted significant attention due to their potential for solving global water scarcity problems. In this study, we investigate the impact of titanium oxide (TiO2) and titanium oxide/reduced graphene (TiO2/rGO) additions on the performance of TFN-FO membranes, specifically focusing on water flux and reverse salt diffusion. Membranes with varying concentrations of TiO2 and TiO2/rGO were fabricated as interfacial polymerizing M-phenylenediamine (MPD) and benzenetricarbonyl tricholoride (TMC) monomers with TiO2 and its reduced graphene composites (TiO2/rGO). The TMC solution was supplemented with TiO2 and its reduced graphene composites (TiO2/rGO) to enhance FO performance and reverse solute flux. All MPD/TMC polyamide membranes are characterized using various techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements. The results demonstrate that incorporating TiO2/rGO into the membrane thin layer improves water flux and reduces reverse salt diffusion. In contrast to the TFC membrane (10.24 L m-2h-1 and 6.53 g/m2 h), higher water flux and higher reverse solute flux were detected in the case of TiO2and TiO2/rGO-merged TFC skin membranes (18.81 and 24.52 L m-2h-1 and 2.74 and 2.15 g/m2 h, respectively). The effects of TiO2 and TiO2/rGO stacking on the skin membrane and the performance of TiO2 and TiO2/rGO skin membranes have been thoroughly studied. Additionally, being investigated is the impact of draw solution concentration.

Biochemical and proteomic response of the freshwater green alga Pseudochlorella pringsheimii to iron and salinity stressors.

BACKGROUND: Pseudochlorella pringsheimii (Ppr) is a green unicellular alga rich with chlorophyll, carotenoids, and antioxidants. As a widespread organism, Ppr must face, and adapt to, many environmental stresses and these are becoming more frequent and more extreme under the conditions of climate change. We therefore focused on salinity induced by NaCl and iron (Fe) variation stresses, which are commonly encountered by algae in their natural environment. RESULTS: The relatively low stress levels improved the biomass, growth rate, and biochemical components of Ppr. In addition, the radical-scavenging activity, reducing power, and chelating activity were stimulated by lower iron concentrations and all NaCl concentrations. We believe that the alga has adapted to the stressors by increasing certain biomolecules such as carotenoids, phenolics, proteins, and carbohydrates. These act as antioxidants and osmoregulators to protect cell membranes and other cellular components from the harmful effects of ions. We have used SDS-PAGE and 2D-PAGE in combination with tandem mass spectrometry to identify responsive proteins in the proteomes of stressed vs. non-stressed Ppr. The results of 2D-PAGE analysis showed a total of 67 differentially expressed proteins, and SDS-PAGE identified 559 peptides corresponding to 77 proteins. Of these, 15, 8, and 17 peptides were uniquely identified only under the control, iron, and salinity treatments, respectively. The peptides were classified into 12 functional categories: energy metabolism (the most notable proteins), carbohydrate metabolism, regulation, photosynthesis, protein synthesis, stress proteins, oxido-reductase proteins, transfer proteins, ribonucleic-associated proteins, hypothetical proteins, and unknown proteins. The number of identified peptides was higher under salinity stress compared to iron stress. CONCLUSIONS: A proposed mechanism for the adaptation of Ppr to stress is discussed based on the collected data. This data could serve as reference material for algal proteomics and the mechanisms involved in mediating stress tolerance.

Cooperative antioxidative defense of the blue-green alga Arthrospira (Spirulina) platensis under oxidative stress imposed by exogenous application of hydrogen peroxide.

Hydrogen peroxide (H2O2) is an environmentally-safe algaecide used to control harmful algal blooms and as a disinfectant in various domestic and industrial applications. It is produced naturally in sunny-water or as a by-product during growth, and metabolism of photosynthetic organisms. To assess the impact of H2O2 on Arthrospira platensis, several biochemical components, and antioxidant enzymes were analysed. The growth and biomass of A. platensis were decreased under the effect of H2O2. Whereas, the concentration up to 40 µM H2O2 non-significantly induced (at P < 0.05) the Chl a, C-phycocyanin (C-PC), total phycobiliprotein (PBP), and the radical scavenging activity of A. platensis. The half-maximal effective concentrations (EC50) for H2O2 were 57, 65, and 74 µM H2O2 with regards to the biomass yield, Chl a, and C-PC content, respectively. While, the total soluble protein, and soluble carbohydrates contents were significantly induced. However, the higher concentrations (60 and 80 µM) were lethal to these components, in parallel to the initiation of the lipid peroxidation process. Surprisingly, the carotenoids content was non-significantly increased by H2O2. Despite the relative consistency of catalase (CAT), the activities of superoxide dismutase (SOD) and peroxidase (POD) enzymes were boosted by all of the tested concentrations of H2O2. The relative transcript abundance of selected regulatory genes was also investigated. Except for the highest dose (80 µM), the tested concentrations had almost inhibitory effect on the relative transcripts of heat shock protein (HSP90), glutamate synthase (GOGAT), delta-9 desaturase (desC), iron-superoxide dismutase (FeSOD) and the Rubisco (the large subunit, rbcL) genes. The results demonstrated the importance of the non-enzymatic and enzymatic antioxidants for the cumulative tolerance of A. platensis.

Antioxidant enzymes of Pseudochlorella pringsheimii under two stressors: variation of SOD Isoforms activity.

Algae are always facing the challenge of exposure to different stress conditions, therefore raising challenges of adaptation for survival. In this context, the growth and the antioxidant enzymes of the green stress-tolerant alga Pseudochlorella pringsheimii were investigated under two environmental stresses viz. iron and salinity. The number of algal cells was moderately increased by iron treatment in the range of 0.025-0.09 mM of iron, yet, the number of cells decreased at high iron concentrations (0.18 to 0.7 mM Fe). Furthermore, the different NaCl concentrations (8.5-136.0 mM) had an inhibitory effect on the algal cell number, compared to the control.The superoxide dismutase (SOD) showed three isoforms namely; Mn, Fe, and Cu/Zn SOD. The in gel and in vitro (tube-test) activities of FeSOD were higher compared with the other SOD isoforms. The activity of total SOD and its isoforms increased significantly by the different concentrations of Fe and non-significantly by NaCl. The maximum SOD activity was recorded at 0.7 mM Fe (67.9% above control). The relative expression of FeSOD was high under iron and NaCl at 8.5 and 34 mM, respectively. However, FeSOD expression was reduced at the highest NaCl tested concentration (136 mM). In addition, the antioxidant enzyme activity of catalase (CAT) and peroxidase (POD) were accelerated by increasing iron and salinity stress which indicates the essential role of these enzymes under stress. The correlation between the investigated parameters was also investigated. A highly significant positive correlation between the activity of total SOD and its isoforms, and with the relative expression of FeSOD was observed.

Dietary Chlorella vulgaris effectively alleviates oxidative stress, immunosuppression, and enhances the resistance to Streptococcus agalactiae infection in cadmium-intoxicated Nile tilapia fingerlings.

Aquatic pollutants, including cadmium (Cd), cause oxidative stress on aquatic animals. The use of probiotics, including microalgae as a feed additive to alleviate the toxic impacts of heavy metals, is a much more interesting point. Hence, the current study investigated the oxidative stress and immunosuppression in Nile tilapia (Oreochromis niloticus) fingerlings caused by Cd toxicity as well as the preventive function of dietary Chlorella vulgaris against Cd toxicity. Accordingly, fish were fed on 0.0 (control), 5, and 15 g/kg diet of Chlorella up to satiation thrice a day, along with being exposed to 0.0 or 2.5 mg Cd/L for 60 days. Following the experimental procedure, fish from each group were intraperitoneally injected with Streptococcus agalactiae, and their survivability was observed for further ten days. Chlorella-supplemented diets meaningfully (P < 0.05) boosted the antioxidative capability of fish, which was evidenced by higher activities of hepatic superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) as well as higher levels of reduced glutathione (GSH) along with significant reductions in hepatic malondialdehyde levels. Moreover, the innate immunity indices [phagocytic activity (PA), respiratory burst activity (RBA), and alternative complement activity (ACH50)] were significantly higher in Chlorella-fed fish, particularly in the group of 15 g/kg diet. Additionally, serum of Chlorella-fed fish showed potent bactericidal activities against S. agalactiae, particularly at the treatment of a 15 g/kg diet. Feeding Chlorella diets to Nile tilapia fingerlings upregulated SOD, CAT, and GPx genes expression alongside the down-regulation of IL-1ß, IL-8, IL-10, TNF-α, and HSP70 genes expression. Conversely, Cd toxicity caused oxidative stress and suppressed the fish's innate immunity with upregulation of the expression of IL-1ß, IL-8, IL-10, TNF-α, and HSP70 genes. Feeding Cd-exposed fish on Chlorella-containing diets attenuated these adverse effects. The current research revealed that supplementing feeds with the treatment of 15 g/kg diet of C. vulgaris supports the antioxidant-immune responses and alleviates the Cd toxicity effects on Nile tilapia fingerlings.

Biosorption of uranium by immobilized Nostoc sp. and Scenedesmus sp.: kinetic and equilibrium modeling.

Different activities related to uranium mining and nuclear industry may have a negative impact on the environment. Bioremediation of nuclear pollutants using microorganisms is an effective, safe, and economic method. The present study compared the uranium biosorption efficiency of two immobilized algae: Nostoc sp. (cyanophyte) and Scenedesmus sp. (chlorophyte). Effects of metal concentration, contact time, pH, and biosorbent dosage were also studied. The maximum biosorption capacity (60%) by Nostoc sp. was obtained at 300 mg/l uranium solution, 60 min, pH 4.5, and 4.2 g/l algal dosage, whereas Scenedesmus sp. maximally absorbed uranium (65 %) at 150 mg/l uranium solution, 40 min, pH 4.5, and 5.6 g/l of algal dosage. The interaction of metal ions as Na2SO4, FeCl3, CuCl2, NiCl2, CoCl2, CdCl2, and AlCl3 did not support the uranium biosorption by algae. The obtained data was adapted to the linearized form of the Langmuir isotherm model. The experimental qmax values were 130 and 75 mg/g for Nostoc sp. and Scenedesmus sp., respectively. Moreover, the pseudo-second-order kinetic model was more applicable, as the calculated parameters were close to the experimental data. The biosorbents were also characterized by Fourier-transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) analyses. The results suggest the applicability of algae, in their immobilized form, for recovery and biosorption of uranium from aqueous solution.

Disparity of the carotenoids antioxidant properties of wild-type and D-PSY-transgenic Dunaliella parva strains under three environmental stresses.

Two strains of the halophilic alga Dunaliella parva, a wild type (WT) and a transgenic strain (D-PSY) containing an exogenous phytoene synthase gene (PSY), were used to investigate the growth, carotenoid accumulation, and carotenoid antioxidant properties under nitrogen starvation, cobalt and biochar treatments. D-PSY had higher carotenoid content (1.8 times) compared to the WT. The applied stressors stimulated the carotenoid content of both WT and D-PSY especially. The carotenoids were assayed for the potential antioxidant activities by five different assays. Generally, the antioxidant activities of D-PSY carotenoids were superior to that of WT. The biochar and nitrogen treatments generally enhanced the antioxidant activities of the carotenoids, whereas cobalt came third in this respect. The D-PSY transgenic algal strain has both high carotenoids content and antioxidant properties which enhanced under the relatively lower concentrations of the applied stressors. The results have shown to lead to an accurate application of the transgenic alga as a source of potent antioxidant compounds. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01077-0.

Biosorption of cyanate by two strains of Chlamydomonas reinhardtii: evaluation of the removal efficiency and antioxidants activity.

Two strains of the chlorophyte Chlamydomonas reinhardtii, a wild type (WT) and a transgenic strain (C.CYN) contained an exogenous cyanase gene (CYN), were used to investigate the growth and cyanate biosorption capability through the analysis of the adsorption equilibrium isotherm. The potential antioxidants activity of the algal strains was also investigated under cyanate concentration. The antioxidants activity of both C.CYN and WT were enhanced by the application of cyanate.Two adsorption isotherm models and the sorption kinetics were used to check the efficiency of the cyanate removal process. The results showed the biosorbent efficiency of Chlamydomonas in the removal of KCNO from aqueous solution. The C.CYN strain has great efficiency to remove cyanate as compared to the WT. The maximum percentage of cyanate removal was 83.75% for the C.CYN and 50% for the WT as treated with 0.8 mg.ml-1 KCNO. The data were adapted to the nonlinear Langmuir model on the basis of the coefficient of determination. The calculated qmax was 0.54 and 0.42 µg.mg-1 for C.CYN and WT which correlated to the experimental one (0.67 and 0.4 µg.mg-1, respectively). Our data highlight the application of the transgenic algal strain toward the removal of highly toxic materials as cyanate.Novelty statement The main objective of this work is to find out an efficient genetically-modified Chlamydomonas strain to remove the highly toxic cyanate compound from contaminated area. Moreover, to evaluate the biosorption ability of this transgenic strain with its wild one via two adsorption isotherm (the Langmuir and Freundlich) models. Also, to estimate the antioxidants activity of these strains under the cyanate toxicity through four different assays.

Molecular characterization and expression analysis of iron superoxide dismutase gene from Pseudochlorella pringsheimii (Trebouxiophyceae, Chlorophyta).

The FeSOD isoforms of Pseudochlorella pringsheimii were identified, a preliminary characterization of the enzyme was conducted, and the relationship among the FeSOD gene from P. pringsheimii and that of other organisms was examined. The FeSOD has an open reading frame of 612 bp that encodes 203 deduced amino acids with a molecular mass of 23 kDa. Expression of the recombinant FeSOD gene was done successfully in Escherichia coli. The purified FeSOD has a specific enzyme activity that reached 688 U mg-1 protein (in vitro assay). Alkaline conditions showed the highest activity for the recombinant FeSOD. Moreover, it showed a relative thermostability up to 50 °C, while at 50 and 70 °C, the activity was reduced by 32 and 68%, respectively, after 1 h as compared to the maximum. Phylogenetic analysis revealed three main clusters i.e., the prokaryotic Cyanophyta, bacteria, and the eukaryotic Chlorophyta intermingled with plant species and a dinoflagellate. P. pringsheimii was closely grouped with Chlorella pyrenoidosa, however, other species showed a relative disparity. Alignment of FeSOD gene sequences of the different species showed many conserved regions which could be used for FeSOD sequences among unexplored species and may be useful for the taxonomy of the revised coccoid Chlorella species.

Tolerance of Pseudochlorella pringsheimii to Cd and Pb stress: Role of antioxidants and biochemical contents in metal detoxification.

The tolerance and antioxidant response of the green alga P. pringsheimii to cadmium (Cd) and lead (Pb) was investigated. The algal biomass was constant at the relatively lower metal concentrations of Cd and Pb (5, 12 µM, and 2.5-200 µM, respectively), whereas higher concentrations severely inhibited the algal biomass yield. The pigment content of P. pringsheimii decreased due to the investigated metals, especially with Cd concentrations. However, the Pb concentrations of 2.5-200 µM enhanced the pigment content. The carotenoids content was highly repressed by the Cd concentrations. Nevertheless, Pb concentrations highly stimulated the carotenoids content, with the exception of 400 and 500 µM Pb. The biochemical contents of P. pringsheimii including phenolic, total soluble protein and carbohydrate contents responded variably to the investigated metals. The concentrations of Cd were found to be harmful to total soluble protein and carbohydrates, but not the phenolic contents. However, all biochemical contents were stimulated under relatively lower Pb concentrations. Markedly for Pb, the radical scavenging, reducing power, and chelating activities improved under the metals exposure excluding higher concentrations. The activities of the antioxidant enzymes (SOD, CAT, and POD) were highly stimulated with all treatments (except for CAT activities at the highest Cd and Pb concentrations, 300 and 500 µM, respectively). Remarkably, Cd treatments have higher antioxidant enzyme activities compared to that of Pb treatments. The antioxidants augmentation of P. pringsheimii under the metal stress may be exploited for future application in several fields.

Biochemical composition and antioxidant activities of Arthrospira (Spirulina) platensis in response to gamma irradiation.

Arthrospira (Spirulina) platensis is a blue-green alga, rich with bioactive components and nutrients. To evaluate effect of gamma irradiation, A. platensis was exposed to different doses of 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5kGy. The data showed that the phenolic and proline contents significantly increased with the increase of gamma irradiation doses up to 2.0kGy, above which a reduction was observed. The soluble proteins and malondialdehyde (MDA) contents were stimulated by all tested irradiation doses. Furthermore, the vitamins (A, K and B group) and mineral contents (N, P, Na, K, Ca, Mg and Fe) were stimulated by the irradiation doses compared with the control. The activities of some N-assimilating and antioxidant enzymes were significantly increased with the irradiation doses up to 2.0kGy. This study suggests the possible use of gamma irradiation as a stimulatory agent to raise the nutritive value and antioxidant activity of A. platensis.

Cilostazol determination by the enhancement of the green emission of Tb3+ optical sensor.

The efficiency of excited-state interaction between Tb(3+) and the industrial product Cilostazol (CIL) has been studied in different solvents. High luminescence intensity peak at 545 nm of terbium complex in acetonitrile was obtained. The photophysical properties of the green emissive Tb(3+) complex have been elucidated, the terbium was used as optical sensor for the assessment of CIL in the pharmaceutical tablets and body fluids at pH 3.1 and λ(ex) = 320 nm with a concentration range 1.0 × 10(-9)-1.0 × 10(-6) mol L(-1) of CIL, correlation coefficient of 0.998 and detection limit of 7.5 × 10(-10) mol L(-1).

Spectrofluorimetric assessment of doxycycline hydrochloride in pharmaceutical tablets and serum sample based on the enhancement of the luminescence intensity of the optical sensor Sm3+ ion.

A simple and sensitive spectrofluorimetric method for determination of trace amount of doxycycline hydrochloride (DC) in pharmaceutical tablets and serum samples was developed. In ammonia buffer solution of pH 8.9 the doxycycline hydrochloride can remarkably enhance the luminescence intensity of the Sm(3+) ion in Sm(3+)- DC complex at λ(ex)=400 nm. The produced luminescence intensity of Sm(3+)- DC complex in DMSO is in proportion to the concentration of DC and used as optical sensor for its determination. The dynamic range for the determination of DC is 1 × 10(-8)-5 × 10(-6) mol L(-1) and in case of quantum yield calculations is 7 × 10(-9)-5 × 10(-6) mol L(-1) with detection limit of 6.5 × 10(-10) mol L(-1). The enhancement mechanism of the luminescence intensity in the Sm(3+)- DC system has been also discussed. A comparison with other spectrofluorimetric methods for tetracycline derivatives in which Eu(3+) ion is used instead of Sm(3+) ion is also studied.

Amelioration of lead toxicity on rat liver with Vitamin C and silymarin supplements.

The aim of the present study was to investigate the impact of the combined administration of Vitamin C and silymarin on lead toxicity. Male albino rats were subdivided into three groups: the first was a control group, the second received lead acetate in diet as 500 mg/kg diet daily, the third received the same lead acetate dose and supplemented with Vitamin C (1 mg/100g body weight) and silymarin (1 mg/100g body weight) by gastric tube three times per week. Blood samples were taken after 2, 4 and 6 weeks of treatment. Significant lead-induced elevations in serum ALT, AST, GGT and ALP activities were observed after different periods of treatment. However, serum LDLc was decreased. The intensities of RNA and apoptotic fragments of DNA were measured as optical density by Gel-pro program. Lead acetate decreased the intensity of DNA at 6 weeks and induced apoptotic DNA fragments reversibly with time. After 2 weeks of lead administration dilation and congestion of terminal hepatic veins and portal vein branches were observed. Lead also induced hepatocyte proliferation without any localized distribution among zones 1-3. Portal inflammatory infiltrate with disruption of the limiting plates (interface hepatitis), steatosis, apoptosis and mild fibrosis were detected especially by sixth week of lead administration. Combined treatment of lead-exposed animals with Vitamin C and silymarin showed marked improvement of the biochemical, molecular and histopathological findings. These experimental results strongly indicate the protective effect of Vitamin C and silymarin against toxic effects of lead on liver tissue.

Host-parasite relationships between Schistosoma mansoni and Echinostoma liei and their intermediate host Biomphalaria alexandrina using RAPD-PCR analysis.

Biomphalaria alexandrina are known to be intermediate hosts for both Schistosoma mansoni and Echinostoma liei. RAPD-PCR assay offers a new approach to host-parasite relationships. This was performed by investigating the genetic variation and compatibility among S. mansoni, E. liei and their intermediate host B. alexandrina with special emphasis on variations occurring in snails infected with S. mansoni and/or E. liei. Six primers were screened for DNA analysis and gave total patterns from 28 to 37 reproducible bands for each species. All specimens analyzed by the RAPD-PCR gave interpretable electrophoretic banding patterns that were polymorphic and compatible in the amplified products of these primers within each species.

Cryptosporidiosis in Benha, study of some recent modalities in diagnosis and treatment.

A total prevalence of cryptosporidiosis was carried out on 1087 diarrheal patients of all age groups attending the outpatient clinics using modified Ziehl-Neelsen stain (MZN) and Meriflour direct immunofluorescent technique (IFA). IFA was more sensitive, specific and gave positive results 19.5% than MZN stain which gave a positivity 13.5% Cases were divided into 3 groups, each group was treated by one of nitazoxanid (NTZ), or co-trimoxazole or placebo. The most effective drug was NTZ which cured 39 patients (79.6%) out of 49 patients followed by co-trimoxazole that gave cure of 20 (41.6%) out of 48 patients. Placebo cured 20 (40%) out of 50 patients.

Human chronic fascioliasis: hepatitis B and C among infected cases.

Sera from one hundred and fifty three chronic Fasciola cases were screened for the presence of HB markers (HBsAg, anti HBc and anti HBs) and anti HCV using ELISA technique. Quantitative stool examination and estimation of liver enzymes (AST-ALT-bilirubin) levels of the study population were performed. HBsAg was present in 5 (3.3%), anti HBs in 13 (8.5%), HBexposed (HBex) in 44 (28.8%) and anti HCV in 13 (8.5%) of examined sera. HBV and HCV markers were significantly higher among older age groups. Concerning familial aggregation of hepatitis markers, 7 (15.9%) of the 44 HBex cases had two individuals per family who had evidence of exposure to HBV. No significant change in Fasciola GMEC and liver function tests have been noticed.

Epidemiology of breast cancer, descriptive and analytical review.

The descriptive portion of this review explores briefly the historical literature for breast cancer. Also, it discusses occurrence, morbidity, mortality, personal risk factors, geographical distribution, effects of time and the latent period of breast cancer. The analytical portion of this review describes the role of genetics, viral and bacterial agents, glandular secretion and diet on the pathogenesis of breast cancer. In conclusion a variety of interrelated genetic, environmental and endocrine factors appear to be associated with increased risk of breast cancer, but no single factor or combination of variables presently known is sufficient to explain the etiology of this malignancy.

Prevalence of trachoma in school children and ophthalmological outpatients in rural Egypt.

The prevalence of trachoma in school children and ophthalmological patients in rural villages of the Qalyub Governorate of Egypt was determined by clinical and laboratory diagnostic procedures and reported as mild, moderate, or severe according to the WHO classification scheme. Of 777 primary school students examined in 3 villages, 204 (26%) had clinically active trachoma. The overall prevalence of the disease in this population ranged from 16% to 35%. The prevalence of infection was higher in younger groups and decreased throughout primary school. Of 312 patients with ocular complaints examined at the village outpatient clinics, 100 (32%) had trachoma infections. Monoclonal FA staining showed higher sensitivity in detecting positive cases of trachoma than did Giemsa staining. This study has shown that trachoma is still prevalent in rural Egypt and that the monoclonal FA staining is a relatively sensitive and practical test for the laboratory diagnosis of trachoma in a field study, where reasonable facilities for culture diagnosis are not available.