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Isolation of urease-producing bacteria and their effects on reducing Cd and Pb accumulation in lettuce (Lactuca sativa L.) Полный текст
2020
Wang, Tiejun | Wang, Shilin | Tang, Xingchun | Fan, Xianpeng | Yang, Sheng | Yao, Lunguang | Li, Yadong | Han, Hui
Excess Cd and Pb in agricultural soils enter the food chain and adversely affect all organisms. Therefore, it is important to find an eco-friendly way to reduce heavy metal accumulation in vegetables. We used urea agar plates to isolate urease-producing bacteria from the rhizosphere soil of lettuce in Cd- and Pb-contaminated farmland and investigated their ability to produce urease and immobilize heavy metals. The effects of these strains on the biomass, quality, and Cd and Pb accumulation of lettuce were also studied. The results showed that two urease-producing bacteria, Enterobacter bugandensis TJ6 and Bacillus megaterium HD8, were screened from the rhizosphere soil of lettuce. They had a high ability to produce urease (44.5 mS cm⁻¹ min⁻¹ OD₆₀₀⁻¹ and 54.2 mS cm⁻¹ min⁻¹ OD₆₀₀⁻¹, respectively) and IAA (303 mg L⁻¹ and 387 mg L⁻¹, respectively). Compared with the control, inoculation with strains TJ6 and HD8 reduced the Cd (75.3–85.8%) and Pb (74.8–87.2%) concentrations and increased the pH (from 6.92 to 8.13–8.53) in solution. A hydroponic experiment showed that the two strains increased the biomass (31.3–55.2%), improved the quality (28.6–52.6% for the soluble protein content and 34.8–88.4% for the vitamin C (Vc) content), and reduced the Cd (25.6–68.9%) and Pb (48.7–78.8%) contents of lettuce shoots (edible tissue). In addition, strain HD8 had a greater ability than strain TJ6 to reduce lettuce Cd and Pb uptake and water-soluble Cd and Pb levels in solution. These data show that the urease-producing bacteria protect lettuce against Cd and Pb toxicity by extracellular adsorption, Cd and Pb immobilization, and increased pH. The effects of heavy metal immobilization by the two strains can guarantee vegetable safety in situ for the bioremediation of heavy metal–polluted farmland.
Показать больше [+] Меньше [-]Pathological evidence in Plicopurpura pansa associated with the stranding of a bulk carrier ship during Hurricane “Patricia” in the Mexican Central Pacific Полный текст
2020
Liñán-Cabello, Marco A. | Liñán-Rico, Viridiana | Ortega-Ortíz, Christian | Verduzco-Zapata, Manuel
Due to the effects of Hurricane Patricia (2015), the bulk freighter “El Llanitos” ran aground in the rocky intertidal zone of Colima, Mexico. We assessed the impact of this ship’s stranding on a population of the gastropod Plicopurpura pansa. Toxic elements, hydrocarbons, shell deformities, presence of tumors, imposex, and morphological relationships were analyzed. Two years after the stranding occurred, high cyanide concentrations (0.0363 mg/l) and Ni concentrations above permissible limits (3.35 mg/l) were found in surface seawater. Hydrocarbon concentrations were high in the aft zone of the ship and decreased towards the bow area of the freighter. The P. pansa specimens collected closest to the ship structure presented a high prevalence of tumorations in the structure of the foot and morphological anomalies in the shell structure; imposex was 32% and there was evidence of effects on the growth indicator. The evidence presented here supports the existence of a significant impact from the grounding of the ship on a protected gastropod species associated with the rocky intertidal zone on the coast of Colima. The potential of P. pansa as a bioindicator species of pollution caused by toxic elements and hydrocarbons associated with stranding events in the tropical Pacific is documented.
Показать больше [+] Меньше [-]Synthesis of nickel nanoparticles using Citrullus colocynthis stem extract for remediation of Reactive Yellow 160 dye Полный текст
2020
Kiran, Shumaila | Rafique, Muhammad Asim | Iqbal, Sarosh | Nosheen, Sofia | Naz, Saba | Rasheed, Abdur
In current years, pollution caused by synthetic dyes has become one of the most serious environmental issues. By rapidly developing industrial units, effluents having synthetic dyes are directly or indirectly being discharged into the environment. Bio-sorption is cost-effective way for the eradication of toxic dyes present in textile effluent. The present study involves the synthesis of nickel nanoparticles using Citrullus colocynthis stem extract. The characterization of synthesized nickel nanoparticles (Ni-NPs) was done by SEM. The synthesized Ni-NPs were used to degrade the Reactive Yellow 160 dye following the optimization of different experimental parameters. The maximum decolorization (91.4%) was obtained at 0.02% dye conc., 9 mg/L conc. of Ni-NPs, pH 7 at 40 °C. TOC and COD were used to assess the efficiency of this experiment. Percent reduction in COD and TOC was found to be 84.35% and 83.24% respectively. The degradation pathway of dye under study confirmed the formation of non-toxic end-products.
Показать больше [+] Меньше [-]Effects of nitrogen and phosphorus limitations on fatty acid methyl esters and fuel properties of Dunaliella salina Полный текст
2020
Almutairi, Adel W.
This study was designed to assess the synergistic effects of nitrogen (N) and phosphorus (P) concentrations on oil content, fatty acid profile, and predicted fuel properties of Dunaliella salina. Axenic D. salina cells were grown in F/2 growth medium of salinity 34 ppt containing 33.6 g.l⁻¹ ultramarine synthetic sea salt. Growth dry weight, cell count, and their relationship were measured, and oils were extracted by soaking following Soxhlet extraction. Growth dry weight was markedly affected by N and P concentrations, with maximum growth dry weights of cultures grown at recommended N and P concentrations (control), half of the recommended N concentration (0.5 N) and (0.5 N/0.5P) being 0.911 g.l⁻¹, 0.755 g.l⁻¹, and 0.615 g.l⁻¹, respectively. Oil content showed the reverse pattern, with cultures grown in the absence of phosphorus (0.0P), full N/P starvation (0.0 N/0.0P), and control resulting in maximum oil contents of 24.86%, 22.85%, and 5.88%, respectively. The majority of fatty acid methyl esters ranged between C14 and C22. Estimated fuel properties of algal cells grown under NP stress conditions were found to meet the American Society for Testing and Materials (ASTM) and European Committee for Standardization (EN) guidelines.
Показать больше [+] Меньше [-]Enhancement of PV/T-integrated single slope solar desalination still productivity using water film cooling and hybrid composite insulation Полный текст
2020
Balachandran, Gurukarthik Babu | David, Prince Winston | Vijayakumar, Aravind Bhaskar Panayilvedu | Kabeel, Abd Elnaby | Athikesavan, Muthu Manokar | Sathyamurthy, Ravishankar
This context is about enhancing the freshwater production of a single slope solar desalination still (SSSDS) using water film cooling over the glass cover and using hybrid natural fibre composite (HNFC) insulation. In contrast to the conventional insulations, we proposed the HNFC insulation; this composite was made of natural fibre Pharsalus vulgaris (6 %) and nano-silica (1 %) with unsaturated polyester resin. In this study, conventional SSSDS and proposed SSSDS with enhanced evaporation and condensation have been designed. The same was built with native materials. A conventional and proposed type SSSDS was subjected to the same experimental condition. The experimental result showed that using water film cooling over glass cover and HNFC insulation at 0.5 cm depth caused a 35% increase in the amount of distilled water when compared with the conventional type SSSDS with polystyrene—Styrofoam (thermocol) insulation. Water film cooling over glass cover and HNFC insulation at 1 cm depth caused a 21% increase in the amount of distilled water when compared with the conventional type SSSDS with thermocol insulation. The conventional type solar desalination still with thermocol insulation at 0.5 and 1 cm depth yields are 1.665 and 1.171 l/m²/day, respectively, and the proposed solar desalination still with water film cooling over glass cover and HNFC insulation at 0.5 and 1 cm depth yields are 2.253 and 1.420 l/m²/day, respectively.
Показать больше [+] Меньше [-]Higher body mass index is an important risk factor in COVID-19 patients: a systematic review and meta-analysis Полный текст
2020
Malik, Vivek Singh | Ravindra, Khaiwal | Attri, Savita Verma | Bhadada, Sanjay Kumar | Singh, Meenu
Globally, both obesity and underweight are severe health risks for various diseases. The current study systematically examined the emerging evidence to identify an association between body mass index (BMI) and COVID-19 disease outcome. Online literature databases (e.g., Google Scholar, PubMed, MEDLINE, EMBASE, Scopus, Medrixv and BioRixv) were screened following standard search strategy having the appropriate keyword such as “Obesity”, “Underweight”, “BMI”, “Body Mass Index”, “2019-nCov”, “COVID-19, “novel coronavirus”, “coronavirus disease”. Studies published till 20ᵗʰ April 2020 were included without language restriction. These studies include case reports, case series, cohort, and any other which reported BMI, overweight/obesity or underweight, and its complication with COVID-19 disease. This study observed COVID-19 infection among BMI < 25 kg/m² with prevalence of 0.60 (95%CI: 0.34–0.86, I² = − 76.77) as compared to the 0.34 (95%CI: 0.23–0.44, I² = 53.45% heterogeneity) having BMI > 25 kg/m². The results of the current study show that BMI plays a significant role in COVID-19 severity in all age groups, especially the older individuals. A panel of doctors and nursing staff should review COVID-19 patients with higher BMI with other co-morbidities (diabetes and hypertension), and they should be given increased vigilance, priority in testing, and treatment to control the associated co-morbidities. Further, the COVID-19 patients whose illness entered 7–10 days, age > 50 years, and elevated CRP levels should be given additional medical considerations. Our finding showed that the population and patients with high BMI have moderate to high risk of medical complications with COVID-19, and hence, their health status should be monitored more frequently including monitoring of blood pressure and blood glucose.
Показать больше [+] Меньше [-]Larvicidal and ovicidal activity of carvacrol, p-cymene, and γ-terpinene from Origanum vulgare essential oil against the cotton bollworm, Helicoverpa armigera (Hübner) Полный текст
2020
Gong, Xue | Ren, Yujian
This study evaluated the larvicidal activity, and ovicidal activity of Origanum vulgare EO and its major components against the cotton bollworm, Helicoverpa armigera. The chemical composition of the O. vulgare EO was analyzed by gas chromatography-mass spectroscopy. GC-MS analysis revealed that the O. vulgare EO was composed of ten compounds. The major constituents were carvacrol (78.35%), followed by p-cymene (6.85%) and γ-terpinene (3.70%). In larvicidal activity assay, the O. vulgare EO achieved a LC₅₀ value of 265.51 μg/ml. The three major constituents from the O. vulgare EO were tested individually for toxicity against larvae of H. armigera. Carvacrol, p-cymene, and γ-terpinene appeared to be most effective against H. armigera, with LC₅₀ values of 51.53, 121.32, and 150.15 μg/ml, respectively. Moreover, EC₅₀ values of carvacrol, p-cymene, and γ-terpinene against H. armigera eggs were 33.48, 47.85, and 56.54 μg/ml, respectively. Overall, this study showed that O. vulgare EO and its major constituents have the potential to develop as new eco-friendly insecticides against H. armigera.
Показать больше [+] Меньше [-]Transcriptome analysis revealed cadmium accumulation mechanisms in hyperaccumulator Siegesbeckia orientalis L Полный текст
2020
Xu, Xiaoxun | Zhang, Shirong | Cheng, Zhang | Li, Ting | Jia, Yongxia | Wang, Guiyin | Yang, Zhanbiao | Xian, Junren | Yang, Yuanxiang | Zhou, Wei
Siegesbeckia orientalis L. was identified as a novel Cd-hyperaccumulator and valuable phytoremediation material. However, the molecular mechanisms underlying Cd accumulation in S. orientalis are largely unknown. In this study, RNA-Seq analysis was performed to study the Cd-accumulating mechanisms in its roots with or without Cd treatment. The RNA-seq analysis generated 312 million pairs of clean reads and 78G sequencing data. De novo transcriptome assembly produced 355,070 transcripts with an average length of 823.59 bp and 194,207 unigenes with an average length of 605.68 bp. Comparative transcriptome analyses identified a large number of differentially expressed genes in roots under Cd stress, and functional annotation suggested that S. orientalis utilizes various biological pathways involving many gene networks working simultaneously to cope with the stress. This study revealed that four biological pathways were mainly involved in S. orientalis tolerance to Cd stress, including reactive oxygen species scavenging, phenylpropanoid biosynthesis pathway, Cd absorption and transport, and ABA signaling pathway. The genes related to photosynthesis and heavy metal transport are likely the potential candidates and could be further investigated to determine their roles in Cd tolerance in S. orientalis roots. These findings will be useful to understand the Cd accumulation mechanisms in S. orientalis and facilitate the study of phytoremediation at the molecular level in plants.
Показать больше [+] Меньше [-]Variations in the potassium voltage-gated channel subfamily E regulatory subunit 1 gene associated with noise-induced hearing loss in the Chinese population Полный текст
2020
Ding, Enmin | Wang, Huan | Han, Lei | Zhang, Hengdong | Zhu, Baoli
Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in industrialized countries. It has been recognized to result from interactions between genetic and environmental factors. This study investigated the influence of genetic mutations in the potassium voltage-gated channel subfamily E regulatory subunit 1 (KCNE1) gene on susceptibility to NIHL. A total of 2689 industrial workers in eastern China were recruited to participate. Three single-nucleotide polymorphisms (SNPs) of KCNE1 were genotyped in noise-exposed workers who were classified into 589 cases and 639 control individuals. Then, main effects of the genotypes and their interactions with environmental factors were evaluated. Results showed that the rs3453 C allele located in KCNE1 3'-UTR region and the rs1805127 G allele in the encoding region were associated with increased risk of NIHL in the Chinese population. There is an association between TAA, TAG, and other (CAA/CGA) haplotypes (rs3453-rs11702354-rs1805127) and increased risk of NIHL with OR = 1.33, 1.43, and 2.93 (P = 0.022, 0.017, and 0.001 respectively) compared with CGG group. Results also showed a significant interaction between rs3453, rs1805127, and high-temperature exposure (P = 0.0002, adjusted OR = 1.85). The cellular evidence indicated that polymorphisms rs3453 and rs1805127 may play key roles in hearing loss through affecting KCNE1 expressions by the way of microRNA and protein respectively. The further animal study is still needed to confirm these mechanisms. KCNE1 rs3453 and rs1805127 may have a potential as biomarkers for screening the susceptibility to NIHL.
Показать больше [+] Меньше [-]The potential of elm trees (Ulmus glabra Huds.) for the phytostabilisation of potentially toxic elements in the riparian zone of the Sava River Полный текст
2020
Mataruga, Zorana | Jarić, Snežana | Kostić, Olga | Marković, Milica | Jakovljević, Ksenija | Mitrović, Miroslava | Pavlović, Pavle
The use of trees to immobilise potentially toxic elements (PTEs) is a low-cost and effective method of soil remediation. Thus, the objective of this study was to assess the content of total and bioavailable As, Cd, Cr, Cu, Ni, Pb and Zn in soil samples, as well as their levels in the roots and leaves of elm (Ulmus glabra Huds.) in order to evaluate its potential for the phytostabilisation of PTEs in the riparian zone of the Sava River. Analysis of soils showed that the availability of PTEs ranged from low to medium, while the pollution load index (PLI) and potential ecological risk index (RI) showed that the examined soil fell into the category of uncontaminated to moderately contaminated, as well as into the category of low risk of PTEs contamination. However, the levels of Cr, Cu and Ni in soils were above the critical range for plants. The content of As and Cr measured in roots and leaves was in the toxic range for plants, while the content of Cd and Ni was elevated but not in the toxic range. Bioaccumulation (BCF) and translocation (TF) factors indicated that U. glabra is suitable for the phytostabilisation of As, Cu, Cr, Ni and Pb. Additionally, this species displayed the ability to transport most of the acquired Cu and Zn to the leaves. Correlation analysis showed that PTE content in U. glabra roots was significantly positively correlated to their respective levels in soil (total and DTPA-extractable), except for Cu, indicating that PTE levels in soil strongly influence those in plants. This research into a successful phytoremediating species provides new possibilities when selecting PTE-tolerant native trees in riparian zones of large regional rivers such as the Sava.
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