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文章
Hongfei Zhu* and Xuesong Zhao
Abstract: Bioleaching has become increasingly important in commercial gold extraction because of its economic benefits. Thiobacillus thiooxidans (also known as Acidithiobacillus thiooxidans) is an important participant in synergic bioleaching processes. In this study, a novel strain was isolated from an underground coal mine, identified and named Thiobacillus thiooxidans CGMCC 10329. A consortium of microorganisms including T. ferrooxidans DSM14882, Leptospirillum ferrooxidans CCTCC AB207038 and T. thiooxidans CGMCC 10329 was used to leach four gold ores and four sulfur-containing coal samples; we then determined gold recovery rates and removal rates of elements. The content that may be harmful to the environment, such as sulfur and arsenic contained in the ores, was investigated. The synergic leaching results indicated that the maximum deprivation rates of carbon, sulfur and arsenic were respectively 59.91%, 67.21%, and almost 100%. Bioleaching pretreatment markedly improved the gold recovery rate by 10.7% to 20% in subsequent cyanidation, compared with traditional extraction operations. The average sulfur removal rate by synergic leaching of the four coal samples was 35.4%. This synergic leaching method, to some extent, broadens gold ore resources and benefits the environment by reducing the impact of coal burning. Keywords: Thiobacillus thiooxidans; synergy; bioleaching; recovery rate; sulfur; deprivation[...] Read More.
Keywords: Thiobacillus thiooxidans; synergy; bioleaching; recovery rate; sulfur; deprivation
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文章
Nkwatoh Athanasius Fuashi *, Labode Popoola , Iyassa Sabastine Mosua , Nkwatoh Ferdinand Wehmbazeyi , Ndumbe Njie Louis and Ewane Marcus Elah
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Linzhu Ren, Lin Wang, Yunzhi Ma* and Xinglong Wang
Abstract: The complete genome of the foot-and-mouth disease virus (FMDV) strain WFL was cloned and sequenced. The results showed that the complete genome was 8155 nucleotides (nt) in length (including the poly(C) tract, but excluding poly(A) tail) and was composed of a 1059-nt 5'-untranslated region (UTR), a 6969-nt open reading frame, and a 127-nt 3'- UTR. cre region of 5’UTR was 55nt with 45.5% of G/C, and had a stem-loop. The stem -loops region of 3’UTR can fold into two stem -loops, SL1 and SL2. A phylogenetic tree was constructed based on complete amino acids sequences of WFL strain and reference strains. The strains were divided into 4 clusters. O/ES/2001, HKN/2002, LZ and WFL strain can be divided into one group. It was obvious that WFL strain had a close relationship to LZ strain, which indicated that the WFL strain was of serotype O. There were 16 different deduced amino acid residues between the WFL strain and the LZ strain.[...] Read More.
Keywords: Food-and-mouth disease virus, sequence, complete genome, untranslated region (UTR).
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文章
Wei Wang, Fang Wang, Xiaofeng Ji, Shanhong Liu, Cui Yuan, and Mi Sun*
Abstract: The gene of psychrophilic catalase BNC from Antarctic Bacillus sp. N2a was cloned by degenerate PCR and inverse PCR. BNC gene revealed a 1,461 bp open reading frame for a protein with 486 amino acids. The phylogenetic tree based on the amino acid sequences of BNC and representative psychrophilic microbial catalases manifested that BNC belonged to the Group III of the monofunctional catalase. The active-site residues of the structure-determined catalase were highly conserved in BNC. Comparison of the amino acid composition of BNC with its mesophilic homologue from Bacillus subtilis TE124 showed that BNC had properties of a cold-active enzyme.[...] Read More.
Keywords: Antarctic Bacillus, monofunctional catalase, cold-adapted enzymes, gene cloning.
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文章
Kemal Dogan, Ismail Celik, Mustafa Gok and Ali Coskan*
Abstract: The effects of different soil tillage methods on rhizobial nodulation, biomass yield (root, shoot and nodule) and nitrogen content of soybean as a second crop have been investigated. The experiment was conducted as a field trial in Cukurova Region, Turkey in 2008. Six different tillage methods have been studied in this research. These methods were conventional tillage with residue (CTR), conventional tillage with burnt residue (CTBR), reduced tillage with heavy disking (RTHD), reduced tillage with rotary tiller (RTR), no- tillage with heavy disking (NTHD) and no tillage with direct seeding (NTDS). At the stage of inflorescence, nodulation was investigated in the root, shoot, and nodule samplings by determining the weights of the samples and analyzing them for nitrogen contents. The results have been statically analyzed by using MSTAT-C package programme. According to the results of the study, under the conventional methods in which deep tillage operations are applied to soil, it has been found out that nodule formation and plant nitrogen contents have been negatively affected. The differences among the applications were found to be statistically significant. In general, the best nodulation has been obtained with NTDS and RTHD plots. Moreover, the effects of other tillage methods on some parameters related with rhizobiyal N2-fixation have caused to considerable decrease on the parameters mentined above.[...] Read More.
Keywords: N2-fixation, soil tillage methods, microbial activity.
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文章
H.O. Edeoga*, D. E. Okwu and B.O Mbaebie
Abstract: Alkaloids, tannins, saponins, steroid, terpenoid, flavonoids, phlobatannin and cardic glycoside distribution in ten medicinal plants belonging to different families were assessed and compared. The medicinal plants investigated were Cleome nutidosperma, Emilia coccinea, Euphorbia heterophylla, Physalis angulata, Richardia bransitensis, Scopania dulcis, Sida acuta, Spigelia anthelmia, Stachytarpheta cayennensis and Tridax procumbens. All the plants were found to contain alkaloids, tannins and flavonoids except for the absence of tannins in S. acuta and flavonoids in S. cayennsis respectively. The significance of the plants in traditional medicine and the importance of the distribution of these chemical constituents were discussed with respect to the role of these plants in ethnomedicine in Nigeria. Keywords: Medicinal plants, ethnomedicine, phytochemical constituents.[...] Read More.
Keywords: Medicinal plants, ethnomedicine, phytochemical constituents.
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文章
Mahdi Eskandari
Abstract: Drought stress is the most significant factor that reduces crop yield and is used as a drug. Using materials such as a plant growth regulator (Brassinosteroids) is a practical solution to reduce losses. Brassinosteroids steroidal plant compounds are broad biological activities that are able to increase plant performance through changes in plant metabolism and in protecting them against environmental stress. In a greenhouse study that was carried out in Vocational City Center Arsanjan, the impact of three levels of irrigation: field capacity (FC), mild stress (FC2/3) and severe stress (FC1/3) and four concentrations of plant growth regulators: Article 28-Homobrassinolid zero, M 10-10, 10-8 M and 10-6 M digits on some savory characters of Satureja bachtiarica was investigated. The results showed that reducing irrigation to reduce the significant effect it has on growth parameters, including length and root dry weight, stem diameter, branch number, plant height, shoot yield and total yield, was essential. More so, the concentration of 10-8 M 28-Homobrassinolid that was significantly used to increase root dry weight, stem diameter, branch number, plant height, total yield and performance was also essential. Percentage oil increased significantly at 1% by reducing irrigation so that 36% oil in full irrigation increased to 87% in severe stress, and 10-8 M was recorded for the use of hormone. Essential oil yield at 5% level under the influence of irrigation and the use of hormones were the most essential functions related to irrigation and the use of 10-8 M 28-Homobrassinolid and value 32/29 kg/ha, respectively. The relationship of these hormone levels in full irrigation, mild and severe stress significantly increased by 59, 30 and 24% oil yield respectively than the control plants did.[...] Read More.
Keywords: Drought stress, Brassinosteroids, essential oil percentage, shoot yield.
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文章
Odenigbo, U. M.* and Otisi, C. A. O.
Abstract: Some positive health benefits have currently been attributed to coconut intake. An attempt has been made to determine the fatty acids and phytochemical contents of coconut seed flesh collected from the different parts of Nigeria. The fatty acid composition was determined by gas chromatography while phytochemical content was detected using the polar and non polar solvents. The findings revealed that samples from eastern Nigeria had highest fatty acids (caprylic: 8.60±0.00%; lauric: 41.30±0.14%; palmitic: 13.00±0.14%, and stearic: 3.6±0.07%) contents. The fats and oil constituent of coconut was more of lauric acid (37.40-41.30%), a medium chain fatty acid considered to be responsible for the many health benefits attributed to coconut consumption. Both solvents used in determination of phytochemicals revealed the presence of alkaloid, resins, glycosides, terpenoids and tannins in all the Nigerian coconut samples. However, saponin was found present in coconut when polar solvent was used while Flavonoids, steroids and acidic compounds were absent with the use of both polar and non polar solvents. The detected phytochemical and beneficial fatty acids revealed that Nigerian coconut seed flesh should be regarded as one of the functional foods in our diets. Thus, the use of coconut seed flesh in our diets should be encouraged for health supporting functions.[...] Read More.
Keywords: Coconut, fatty acids, phytochemicals, functional foods.
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文章
Rebeca Patricia Omena-Garcia, Gilberto Costa Justino, Ladaslav Sodek and José Francisco de Carvalho Gonçalves*
Abstract: The characteristics of symbiotic nitrogen fixation in tropical forest tree species have received little attention but it is well established that mineral N negatively affects symbioses in crop legumes such as soybean and common bean. Nevertheless, ecophysiological mineral nitrogen dynamics in terms of nitrogen xylem transport of native Amazonian legume has been not documented so far. The objective of this study was to evaluate nodulation and amino acid xylem transport of Inga edulis, a tropical Amazonian perennial legume, in response to mineral N. Plant growth, nodule number, nodule dry weight and xylem sap amino acid contents were determined in nodulated I. edulis in response to nutrition with ammonium, nitrate or no mineral N (total dependence on N2 fixation). In addition, free individual amino acids were quantified in the different plant tissues and in the xylem. Plant growth (total dry weight) responded significantly to both nitrate and ammonium, especially the latter. Nitrate negatively affected nodulation and total amino acid transport to the shoot while ammonium increased nodule dry weight, but not total amino acid contents of the xylem which diminished. On the other hand, mineral-N showed only discrete changes in the amino acid composition of the xylem where asparagine was the predominant form. Our results suggest that I. edulis responds to ammonium nutrition through greater plant and nodule growth compared to the other N sources, consistent with ammonium being the principal source of mineral N in the acid soils of the natural habitat of this species.[...] Read More.
Keywords: Tropical tree species, nitrogen fixation, glutamine, symbiosis.
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文章
Manish Das
Abstract: An experiment was carried out with Black Isabgol (Plantago indica L) an annual herb cultivated recently as a medicinal plant at Directorate of Medicinal and Aromatic Plants Research (DMAPR) in India, aiming on the effect at different stages of growth under the influence of different sowing dates and spacings on growth, seed yield and seed swelling factor as a part of good agricultural practices (GAP). No detail morpho-physiological work has been carried out in this species including yield. Results revealed that growth and yield were significantly influenced by sowing dates and spacings. The best time for sowing of P. indica was found to be between 15-30th November and the suitable spacing was either 50 or 60 × 15 cm. Swelling factor was not influenced by these factors, however, a positive trend was observed towards suitable date of sowing and spacing. The finding was a step forward towards determining good agricultural practices (GAP) of P. indica, probably an alternative of P. ovata in future.[...] Read More.
Keywords: Plantago indica, Sowing date, spacing, growth, yield, swelling factor.
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