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Antibiotic resistance, a significant public health hazard, is predicted to cause 10 million deaths worldwide by 2050. The study aimed to identify culturable bioaerosols in the indoor air of dental units in Lahore and assess their antibiotic resistance. Air samples were collected from 10 dental unit locations at different distances, with average concentrations of fungi and bacteria falling within intermediate ranges, per the Global Index of Microbial Contamination (GIMC/m3) index. The study found higher antibiotic-resistant strains in hospital dental units, particularly during winter. The most vigorous strain, S.aureus-NAJIH18, exhibited 70% resistance to ceftazidime. The research highlights the importance of quantifying microbial pollutants for evaluating their source and complexity. It suggests proactive mitigation techniques, such as focused cleaning and air filtration, to improve indoor air quality can mitigate the spread of antibiotic-resistant strains. These insights offer hope in combating the growing public health threat of antibiotic resistance.
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Microbes have shown potential for the bioremediation of tannery waste polluted soil. During our previous study, it was observed that heavy metal resistant Burkholderia cepacia CS8 augmented growth and phytoremediation capability of an ornamental plant. Objective of the present research work was to evaluate the capability of B. cepacia CS8 assisted Calendula officinalis plants for the phytoremediation of tannery solid waste (TSW) polluted soil. The TSW treatment significantly reduced growth attributes and photosynthetic pigments in C. officinalis. However, supplementation of B. cepacia CS8 which exhibited substantial tolerance to the TSW amended soil, augmented growth traits, carotenoid, proline, and antioxidant enzymes level in C. officinalis under toxic and nontoxic regimes. Inoculation of B. cepacia CS8 augmented plant growth (shoot length 13%, root length 11%), physiological attributes (chlorophyll a 14%, chlorophyll b 17%), antioxidant enzyme activities (peroxidase 24%, superoxide dismutase 31% and catalase 19%), improved proline 36%, phenol 32%, flavonoids 14% and declined malondialdehyde (MDA) content 15% and hydrogen peroxide (H2O2) level 12% in C. officinalis at TSW10 stress compared with relevant un-inoculated plants of TSW10 treatment. Moreover, B. cepacia CS8 application enhanced labile metals in soil and subsequent metal uptake, such as Cr 19%, Cd 22%, Ni 35%, Fe 18%, Cu 21%, Pb 34%, and Zn 30%, respectively in C. officinalis plants subjected to TSW10 stress than that of analogous un-inoculated treatment. Higher plant stress tolerance and improved phytoremediation potential through microbial inoculation will assist in the retrieval of agricultural land in addition to the renewal of native vegetation.
During the current study, it was observed that combination of Calendula officinalis and metal tolerant Burkholderia cepacia CS8 not only improved plant growth but also helped phyto-extraction of pollutants present in the tannery solid waste polluted soil. According to our information, research work describing the phytoremediation potential of native metal tolerant microbes and ornamental plants has not been reported in Pakistan.
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Burkholderia cepacia , Calendula , Metais Pesados , Poluentes do Solo , Antioxidantes , Clorofila A , Biodegradação Ambiental , Resíduos Sólidos , Peróxido de Hidrogênio , Solo , Poluentes do Solo/análiseRESUMO
Recent technological advances in nanoscience and material designing have led to the development of point-of-care devices for biomolecule sensing and cancer diagnosis. In situ and portable sensing devices for bedside, diagnosis can effectively improve the patient's clinical outcomes and reduce the mortality rate. Detection of exosomal RNAs by immuno-biochip with increased sensitivity and specificity to diagnose cancer has raised the understanding of the tumor microenvironment and many other technology-based biosensing devices hold great promise for clinical innovations to conquer the unbeatable fort of cancer metastasis. Electrochemical biosensors are the most sensitive category of biomolecule detection sensors with significantly low concentrations down to the atomic level. In this sense, this review addresses the recent advances in cancer detection and diagnosis by developing significant biological sensing devices that are believed to have better sensing potential than existing facilities.
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Two bacterial strains were isolated from sediments and microbial mats of Kingfisher Pond, Antarctica and characterized in a taxonomic study using a polyphasic approach. Cells were strictly aerobic, Gram-stain-negative, rod-shaped, motile (+50 flagellum-specific genes present in the genome sequence; motility observed under microscope) and formed creamy white, half-transparent colonies. Growth occurred at 4 to 28 °C with an optimum at 20 °C, with 0-5.0â% (w/v) NaCl (optimum at 0-1.0â%) and at pH 4.0-11.0 (optimum pH 7.0-9.0). The major fatty acid was C18â:â1ω7c. The respiratory quinone was ubiquinone 10 (Q-10). The DNA G+C content was 60.7 molâ%. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmethanolamine in addition to three unidentified lipids, one unknown glycolipid and five unidentified phospholipids. Comparative analysis of 16S rRNA gene sequences showed highest sequence similarity (98.1â%) to Pararhizobium giardinii H152T, Pararhizobium herbae CCBAU 83011T, and 'Pararhizobium polonicum' F5.1. In silico average nucleotide identity (ANI) and genome-to-genome distance calculator (GGDC) showed 81.1â% identity (ANI) and 22.6â% identity (GGDC) to the closest relative, 'P. polonicum' F5.1. On the basis of phenotypic, phylogenetic, genomic and chemotaxonomic data, the two strains represent a novel species of the genus Pararhizobium, for which the name Pararhizobium antarcticum sp. nov. is proposed. The type strain is NAQVI 59T(=DSM 103442T=LMG 29675T).
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Filogenia , Rhizobiaceae/classificação , Microbiologia da Água , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhizobiaceae/genética , Rhizobiaceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/químicaRESUMO
OBJECTIVE: To examine the effects of airborne endotoxin on lung function impairment in exposure-response relationships among the workers of textile industry. METHODS: The cross-sectional study was conducted at Lahore College for Women University, Lahore, Pakistan, from January to August 2014, and comprised textile mill workers. The participants were divided into exposed and control groups. A questionnaire was used to ask workers about the potential adverse health effects of their occupation. The pulmonary function test was carried out by spirometer. Endotoxin levels in the samples were determined using the key quality characteristics limulus amebocyte lysate. The data was analysed to determine the correlation between the endotoxin exposure duration and pulmonary function test parameters. RESULTS: There were 200 subjects subdivided into 100 each inexposed and control groups. Overall, 160(80%) were not aware of safety measures and the remaining 40(20%) were partially practising. Changes in pulmonary function due to endotoxin exposure showed decreased force vital capacity, flow rate and peak expiratory flow parameters significantly different (p<0.05, p<0.001). The endotoxin concentration was between 12EU/m3 and 300EU/m3. Airborne endotoxin concentrations in textile plants exceeded the Dutch health-based guidance limit of 90EU/m3 and was associated with respiratory health effects. CONCLUSIONS: Prolonged exposure to airborne endotoxin caused constant lung impairment. Proper safety measures should be adopted to avoid the inhalation of cotton dust.
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Fibra de Algodão , Bactérias Gram-Negativas , Pneumopatias , Doenças Profissionais , Exposição Ocupacional/prevenção & controle , Adulto , Estudos Transversais , Poeira/análise , Endotoxinas/análise , Feminino , Humanos , Pneumopatias/diagnóstico , Pneumopatias/etiologia , Pneumopatias/fisiopatologia , Pneumopatias/prevenção & controle , Masculino , Avaliação das Necessidades , Doenças Profissionais/diagnóstico , Doenças Profissionais/fisiopatologia , Doenças Profissionais/prevenção & controle , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Paquistão , Saúde Pública/métodos , Testes de Função Respiratória , Inquéritos e Questionários , Indústria Têxtil/normasRESUMO
Heavy metal toxicity due to industrial wastewater has been a threat to the environment for the past many decades, especially in developing countries. Electroplating Industry wastewater containing heavy metals can become a serious environmental pollutant if not treated appropriately. Present study investigated the removal of nickel and chromium ions from electroplating wastewater using calcined hen eggshells because of it high removal capability, little cost and easy approachability. Characterization of the adsorbent such as proximate analysis, surface charge, X-ray diffraction, and surface area was done prior to adsorption process. Batch adsorption experiment was performed to study the effect of different parameters such as adsorbent dose, contact time, temperature, and pH for adsorbent. Removal percentage of both heavy metals was checked by using calcined eggshell as adsorbent. Comparison was made between nickel and chromium to identify the most effective removal efficacy. It was concluded that utilization of natural waste was found suitable, easier, cost operative and environmental approachable for removal of heavy metals from industrial wastewater. RESEARCH HIGHLIGHTS: To use ecofriendly approach for the treatment of industrial wastewater. To used calcined eggshell as adsorbents for removing metal concentration from industrial wastewater. To find the metal removal potential of calcined eggshell under various environmental conditions like dosage, contact time, temperature, and pH. To checking the efficacy of calcined eggshell.
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Metais Pesados , Poluentes Químicos da Água , Purificação da Água , Animais , Galinhas , Cromo/química , Casca de Ovo/química , Feminino , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/análise , Níquel/análise , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
With the ever-increasing demand of plastics in the world and their consequent disastrous effects on environment, a suitable environmental-friendly substitute like bioplastics/biodegradable plastics is the need time. This study centers on green-production of a variety of bioplastic samples from (1) banana peel starch (BPP) and (2) a composite of banana peel starch, cornstarch and rice starch (COM) with varying amounts of potato peel powder and wood dust powder as fillers, respectively. Two different plasticizers - Glycerol and Sorbitol - have been utilized separately and in a 1:1 combination. A total of 12 samples of each of two types of bioplastics were made using multiple amounts and combinations of the fillers and plasticizers, to test the differences in the physical and chemical characteristics (moisture content, absorption of water, solubility in water, solubility in alcohol, biodegradation in soil, tensile strength, Young's modulus and FT-IR) of the produced samples due to their different compositions. The differences in the properties of the bioplastic samples produced make them suitable for usage in many different applications. All 24 of the samples produced were synthesized using natural and environmentally safe raw material and showed biodegradation, thus proving to be a good alternative to the conventional plastics.
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This study aims to quantify heavy metals (Ni, Pb, Zn, Mn, Cr, Cu and Se) in eggs obtained from poultry farms and backyard raised hens by comparing the concentration of metals in their feed intake. Overall, 90 samples of egg and 12 samples of poultry feed (6 each with food and water) were collected from 3 different poultry farms and backyards located in peri-urban areas of Lahore. A di-acid digestion method was adopted for digestion, after which digested samples were analyzed under atomic absorption spectrophotometer. Results showed that the concentration of Pb, Cr and Se in egg white (Pb = 0.6578, Cr = 0.18 and Se = 0.2161), egg yolk (Pb = 0.7011, Cr = 0.2617 and Se = 0.2656), feed (Pb = 2.585, Cr = 1.3039 and Se = 0.9411) and water (Pb = 0.5483, Cr = 0.1006 and Se = 0.3461) were above permissible limits in both poultry farms (study group 1) and backyards (study group 2). The concentration of metals such as Pb, Mn, Cr, Cu and Se in poultry farms eggs were higher than backyard hen eggs, which may be due to the intake of contaminated feed. So, the current study concluded that the higher concentration of metals in eggs has a positive correlation with the intake of feed contaminated with heavy metals.
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Ração Animal/análise , Ovos/análise , Contaminação de Alimentos/análise , Metais Pesados/análise , Aves Domésticas , Animais , Galinhas , Poluentes Ambientais/análise , Características da Família , Fazendas , Humanos , PaquistãoRESUMO
Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H2O2), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation.
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Arsênio/metabolismo , Mostardeira/fisiologia , Óxido Nítrico/química , Silício/química , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Arsênio/toxicidade , Ascorbato Peroxidases/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Mostardeira/metabolismo , Doadores de Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismoRESUMO
BACKGROUND: Cold storage facilities are the most common workplaces that produce artificially cold work environments and are associated with different adverse effects on human health, work productivity and the occurrence of accidents and injuries. The aim of this study was to measure the antagonistic health effects on workers, so that common factors causing abnormal symptoms could be determined, and to gather basic information to monitor the associated health risks from the exposure to cold work environments. MATERIAL AND METHODS: A cross-sectional analytical study was conducted to investigate the occurrence of cold-related adverse health effects, musculoskeletal symptoms, skin problems, injuries, respiratory illnesses, general hygiene and occupational environment related to cold indoor workplaces, using the Standardized Nordic Questionnaire. A total of 200 subjects took part in this study, including 100 exposed and 100 unexposed to cold environments. A 1-way analysis of variance (ANOVA) and a t-test were applied to measure statistical differences and to differentiate the cases where variations occurred, using SPSS 16. RESULTS: The study revealed that a longer and constant exposure to extremely cold indoor work environments significantly increased (p <0.001) the cold-related symptoms and musculoskeletal disorders which ultimately reduced (p <0.01) the efficiency, effectiveness, performance and work ability of the exposed workers. CONCLUSIONS: The study disclosed various adverse cold-related complaints of the studied subjects who were exposed to extreme cold conditions during a maximum number of working hours. The most consistent problems were related to musculoskeletal discomfort, skin problems and respiratory abnormalities. Med Pr. 2020;71(1):1-7.
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Temperatura Baixa/efeitos adversos , Doenças Musculoesqueléticas/etiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Adulto , Estudos Transversais , Humanos , Masculino , Paquistão , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Extensive milling processes have deprived wheat flour from essential nutrients. The objective of the current study was to assess the nutritive quality of commercial wheat flour (soft flour (SF)) through analyses of proximate composition and functional properties as well as quantification of benzoyl peroxide (BPO; added as bleaching agent in the SF) by comparing the results with whole wheat flour (WF; never received any additives). METHODS: The samples included commercial SF purchased from the local supplier of different flour mills (who use BPO as additive) and a control sample without additives was prepared by grinding the seeds harvested from wheat (Triticum aestivum L.; Inqulab 91) crop grown in the experimental field of University of Agriculture, Faisalabad, under optimized field conditions without any fertilizers and insecticides. Functional properties (including bulk density, water absorption capacity, oil absorption capacity, emulsifying activity, foaming capacity, least gelatinization concentration and gelatinization temperature) and proximate composition (including moisture content, ash contents, crude protein, gluten and starch contents) were determined and compared for all the samples. Benzoyl peroxide (BPO) and Benzoic Acid (BA) quantification was performed through High Performance Liquid Chromatography. Finally dietary intake was estimated for BPO and BA. RESULTS: Results showed that SF had lesser fiber, protein and ash contents, whereas, higher damaged starch, fat, gluten and bulk density. A parallel experiment under selected conditions (temperature, time and solute concentration) showed dissociation of BPO into BA soon after the exposure. Observed BA range (13.77 mg/g after 16 h) in SF and exposure level assessment (44.3 ± 1.36 mg/kg/BW) showed higher intake of BA on the consumption of SF. The results revealed the superiority of WF over SF in nutritive qualities as well as free of toxicants such as BA.
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The title compound, C(14)H(10)BrN(3)O(3)S, crystallizes as two concomitant polymorphs that differ in colour (one yellow and one colourless). Only the structure of the colourless form could be determined. The mol-ecule exists in the thio-amide form with an intra-molecular N-Hâ¯O=C hydrogen bond across the thio-urea system. Mol-ecules are linked into layers parallel to (120) by Brâ¯O(nitro) contacts [3.103â (1)â Å], classical hydrogen bonds from the other NH function to the S atom and N(nitro)â¯O=C contacts. The layers are linked by weak C-Hâ¯O(nitro) hydrogen bonds to produce the observed three-dimensional network.
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In this study, the leaves extract of Cordia myxa, has been used for the first time to synthesize zinc oxide (ZnO) hierarchical microstructures. The solution combustion method was employed as a self-sustaining reaction between zinc nitrate and the leaves extract. The surface properties of leaves mediated ZnO microstructures were determined by UV-Visible spectral analysis, Fourier transform infrared (FT-IR), Cold field emission-scanning electron microscopy (CFE-SEM), Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, the effect of the leaves extract concentration on ZnO structures, size and surface properties was also studied. ZnO structures synthesized employing C. myxa were found to be hexagonal, triangular and round in shape which was determined using CFE-SEM. X-ray diffraction (XRD) analysis confirmed the crystalline nature of compounds. Furthermore, C. myxa mediated ZnO microstructures shows good bactericidal activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.
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Climatic changes pose serious risks to the rural community's livelihoods of many developing countries whereas people in mountainous regions are exposed to multiple hazards with limited livelihood resources and heavy dependence on natural resources. The objective of the current study is to assess the livelihood practices and adaptive capacity of a mountainous region of Pakistan, the Balakot, where people are highly vulnerable to climatic changes. The study uses a triangulation method to explore various issues and options of climate change risks sand adaptation and impact of well-being on resilience capacity and livelihood strategies. For this purpose, ten focus group discussions (FGDs) with carefully selected key informants and structured interviews with randomly selected 200 local households are conducted to evaluate different hazards and their associated livelihood effects. It is observed that the changing climate has significantly influenced livelihoods of the local community in the recent past through resource degradation, gradual unavailability of sufficient basic services (quantity and quality of drinking water, crop food diversity, fuel wood, and non-timber forest products), low agricultural productivity, and social inequity viz. income distribution, health, education, and food storage. Such a brunt is felt disproportionately more by poor households due to their low adaptive capacity to climate change with constrained livelihood resources. The study emphasizes the need for targeted efforts to move from coping strategies to adaptations among people considering their social inequalities. Timely information sharing, livelihood diversification and preservation of livelihood resources such as crop and forest production, livestock grazing, creating awareness on the pace, and pattern of climate change in the region and subsequent role of adaptation options are major interventions that should be emphasized by the public bodies.
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Agricultura/métodos , Mudança Climática , Produtos Agrícolas , Gado , População Rural , Animais , Água Potável , Características da Família , Grupos Focais , Florestas , Humanos , Renda , Paquistão , Distribuição AleatóriaRESUMO
The present investigation was designed to throw light on the microbial status of bakery products available in bakeries and supermarkets of Lahore. Different bakery samples such as biscuits, pizza, patties were collected from different localities such as Anar Kali, Chauburji, Faisal Town, Iqbal Town, Model Town, Muslim Town were investigated for mold and yeast using serial dilution technique inoculated over malt extract agar and potato dextrose agar under sterilized conditions. Isolated fungi were namely Alternaria alternata, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Curvularia americana, Fusarium solani, Penicillium digitatum, Saccharomyces cerevisiae, and Geotrichum candidum. Results depicted maximum fungal viable count in biscuits, collected from Model Town while minimum count was in the samples of Chauburji. In the case of pizza, the maximum fungal viable count was found in the sample of Muslim Town. In the case of patties, the maximum fungal viable count was found in the sample of Muslim Town while minimum count was found in the sample of Iqbal Town. Prevalence of microorganisms may be due to the use of contaminated raw material, use of polluted waters, human handling, and the use of contaminated containers. Contaminated food intake can lead to measurable signs of liver injury, inflammation, etc. Preventive measures like washing and drying of hands before preparing food, cleaning of food preparation areas, and the use of clean equipment can avoid microbes which cause hazards to human health. RESEARCH HIGHLIGHTS: Bakery products of Lahore, Pakistan is investigated for the first time on the basis of light microscopy (LM) and scanning electron microscopy (SEM) and found very significant to check the quality of bakery products or not.
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Contaminação de Alimentos , Microbiologia de Alimentos , Fungos/classificação , Fungos/isolamento & purificação , Contagem de Colônia Microbiana , Fungos/citologia , Fungos/ultraestrutura , Humanos , Microscopia , Microscopia Eletrônica de Varredura , Paquistão , PrevalênciaRESUMO
Recent advances in nanoscience and nanotechnology have also led to the development of novel nanomaterials, which ultimately increase potential health and environmental hazards. Interest in developing environmentally benign procedures for the synthesis of metallic nanoparticles has been increased. The purpose is to minimize the negative impacts of synthetic procedures, their accompanying chemicals and derivative compounds. The exploitation of different biomaterials for the synthesis of nanoparticles is considered a valuable approach in green nanotechnology. Biological resources such as bacteria, algae fungi and plants have been used for the production of low-cost, energy-efficient, and nontoxic environmental friendly metallic nanoparticles. This review provides an overview of various reports of green synthesised zero valent metallic iron (ZVMI) and iron oxide (Fe2O3/Fe3O4) nanoparticles (NPs) and highlights their substantial applications in environmental pollution control. This review also summarizes the ecotoxicological impacts of green synthesised iron nanoparticles opposed to non-green synthesised iron nanoparticles.
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Research on green production methods for metal oxide nanoparticles (NPs) is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO) nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Plant-mediated CuO nanoparticles were found to be oval shaped and well dispersed in suspension. XPS confirmed the elemental composition of P. acerifolium-mediated copper nanoparticles as comprised purely of copper and oxygen. DLS measurements and ion release profile showed that P. acerifolium-mediated copper nanoparticles were more stable than the engineered CuO NPs. Copper oxide nanoparticles are used in many applications; therefore, their potential toxicity cannot be ignored. A comparative study was performed to investigate the bio-toxic impacts of plant-synthesized and engineered CuO nanoparticles on water flea Daphnia. Experiments were conducted to investigate the 48-h acute toxicity of engineered CuO NPs and plant-synthesized nanoparticles. Lower EC50 value 0.102 ± 0.019 mg/L was observed for engineered CuO NPs, while 0.69 ± 0.226 mg/L was observed for plant-synthesized CuO NPs. Additionally, ion release from CuO nanoparticles and 48-h accumulation of these nano CuOs in daphnids were also calculated. Our findings thus suggest that the contribution of released ions from nanoparticles and particles/ions accumulation in Daphnia needs to be interpreted with care.
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The xylanase gene (xynA) of Bacillus licheniformis 9945A was cloned and expressed in Escherichia coli BL21(DE3) using pET-22b(+) as an expression vector. The recombinant xylanase enzyme was purified by ammonium sulfate precipitation, followed by single-step immobilized metal ion affinity chromatography with a 57.58-fold purification having 138.2 U/mg specific activity and recovery of 70.08 %. Molecular weight of the purified xylanase, 23 kDa, was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable for up to 70 °C with a broad pH range of 4-9 pH units. The enzyme activity was increased in the presence of metal ions especially Ca(+2) and decreased in the presence of EDTA, indicating that the xylanase was a metalloenzyme. However, an addition of 1-4 % Tween 80, ß-mercaptoethanol, and DTT resulted in the increase of enzyme activity by 51, 52, and 5 %, respectively. Organic solvents with a concentration of 10-40 % slightly decreased the enzyme activity. The xylanase enzyme possesses the ability of bioconversion of plant biomasses like wheat straw, rice straw, and sugarcane bagasse. Among the different tested biomasses, the highest saccharification percentage was observed with 1 % sugarcane bagasse after 72 h of incubation at 50 °C with 20 units of enzyme. The results suggest that recombinant xylanase can be used in the bioconversion of natural biomasses into simple sugars which could be further used for the production of biofuel.