| 1. |
- Junnarkara, Manisha V., et al.
(författare)
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Evaluation of Probiotic Potential of Lactic Acid Bacteria Isolated from Different Sources in Western India
- 2018
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Ingår i: Food biotechnology. - United Kingdom : Taylor & Francis. - 0890-5436 .- 1532-4249. ; 32:2, s. 112-129
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Tidskriftsartikel (refereegranskat)abstract
- Lactic acid bacteria isolated from unconventional sources are often attractive targets in the quest for obtaining better probiotics. In the present study, 16 members of the genus Lactobacillus, isolated from 3 different sources in western India, viz., plants, fermented foods and beverages, and human feces, were evaluated for their probiotic and bioactive properties. The isolates were closely related to Lactobacillus fermentum, Lactobacillus pentosus, and mainly Lactobacillus plantarum. The isolates were tolerant to bile salt, acidic pH and pancreatin, although pancreatin tolerance was generally low. Cellular extracts of several isolates displayed antioxidant activity, while cell-free supernatants displayed antibacterial activity against human pathogens. Antioxidant activity of Lactobacilli of human origin was higher than those from vegetables or fermented foods and beverages. L. plantarum AG40V prevented spoilage of fresh-cut fruits, vegetables and sprouted mung-beans. Lactobacilli from all sources displayed equal probiotic potential and those of human origin displayed superior antioxidant activity over others.
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| 2. |
- Nahar, Noor, et al.
(författare)
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In silico and in vivo studies of molecular structures and mechanisms of AtPCS1 protein involved in binding arsenite and/or cadmium in plant cells
- 2014
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Ingår i: Journal of Molecular Modeling. - : Springer. - 1610-2940 .- 0948-5023. ; 20:3
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports a continuation of our previous research on the phytochelatin synthase1 (PCS1) gene involved in binding and sequestration of heavy metals or metalloids in plant cells. Construction of a 3D structure of the Arabidopsis thaliana PCS1 protein and prediction of gene function by employing iterative implementation of the threading assembly refinement (I-TASSER) revealed that PC ligands (3GC-gamma-glutamylcysteine) and Gln50, Pro53, Ala54, Tyr55, Cys56, Ile102, Gly161, His162, Phe163, Asp204 and Arg211 residues are essential for formation of chelating complex with cadmium (Cd²⁺) or arsenite (AsIII). This finding suggests that the PCS1 protein might be involved in the production of the enzyme phytochelatin synthase, which might in turn bind, localize, store or sequester heavy metals in plant cells. For validation of the in silico results, we included a T-DNA tagged mutant of Arabidopsis thaliana, SAIL_650_C12, (mutation in AtPCS1 gene) in our investigation. Furthermore, using reverse transcriptase PCR we confirmed that the mutant does not express the AtPCS1 gene. Mutant plants of SAIL_650_C12 were exposed to various amounts of cadmium (Cd²⁺) and arsenite (AsIII) and the accumulation of these toxic metals in the plant cells was quantified spectrophotometrically. The levels of Cd²⁺ and AsIII accumulation in the mutant were approximately 2.8 and 1.6 times higher, respectively, than that observed in the wild-type controlled plants. We confirmed that the results obtained in in silico analyses complement those obtained in in vivo experiments.
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| 3. |
- Nahar, Noor, et al.
(författare)
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Phytoremediation of arsenic from the contaminated soil using transgenic tobacco plants expressing ACR2 gene of Arabidopsis thaliana
- 2017
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Ingår i: Journal of plant physiology (Print). - : Elsevier. - 0176-1617 .- 1618-1328. ; 218, s. 121-126
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Tidskriftsartikel (refereegranskat)abstract
- We have cloned, characterized and transformed the AtACR2 gene (arsenic reductase 2) of Arabidopsis thaliana into the genome of tobacco (Nicotiana tabacum, var Sumsun). Our results revealed that the transgenic tobacco plants are more tolerant to arsenic than the wild type ones. These plants can grow on culture medium containing 200μM arsenate, whereas the wild type can barely survive under this condition. Furthermore, when exposed to 100μM arsenate for 35days the amount of arsenic accumulated in the shoots of transgenic plants was significantly lower (28μg/g d wt.) than that found in the shoots of non-transgenic controls (40μg/g d wt.). However, the arsenic content in the roots of transgenic plants was significantly higher (2400μg/g d. wt.) than that (2100μg/g d. wt.) observed in roots of wild type plants. We have demonstrated that Arabidopsis thaliana AtACR2 gene is a potential candidate for genetic engineering of plants to develop new crop cultivars that can be grown on arsenic contaminated fields to reduce arsenic content of the soil and can become a source of food containing no arsenic or exhibiting substantially reduced amount of this metalloid.
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| 4. |
- Rahman, Aminur, 1984-, et al.
(författare)
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Bioremediation of hexavalent chromium (VI) by a soil-borne bacterium, Enterobacter cloacae B2-DHA
- 2015
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Ingår i: Journal of Environmental Science and Health. Part A. - : Informa UK Limited. - 1093-4529 .- 1532-4117. ; 50:11, s. 1136-1147
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Tidskriftsartikel (refereegranskat)abstract
- Chromium and chromium containing compounds are discharged into the nature as waste from anthropogenic activities, such as industries, agriculture, forest farming, mining and metallurgy. Continued disposal of these compounds to the environment leads to development of various lethal diseases in both humans and animals. In this paper, we report a soil borne bacterium, B2-DHA that can be used as a vehicle to effectively remove chromium from the contaminated sources. B2-DHA is resistant to chromium with a MIC value of 1000 mu g mL(-1) potassium chromate. The bacterium has been identified as a Gram negative, Enterobacter cloacae based on biochemical characteristics and 16S rRNA gene analysis. TOF-SIMS and ICP-MS analyses confirmed intracellular accumulation of chromium and thus its removal from the contaminated liquid medium. Chromium accumulation in cells was 320 mu g/g of cells dry biomass after 120-h exposure, and thus it reduced the chromium concentration in the liquid medium by as much as 81%. Environmental scanning electron micrograph revealed the effect of metals on cellular morphology of the isolates. Altogether, our results indicate that B2-DHA has the potential to reduce chromium significantly to safe levels from the contaminated environments and suggest the potential use of this bacterium in reducing human exposure to chromium, hence avoiding poisoning.
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| 5. |
- Rahman, Aminur, 1984-, et al.
(författare)
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Comparative genome analysis of Lysinibacillus B1-CDA, a bacterium that accumulates arsenics
- 2015
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Ingår i: Genomics. - : Elsevier. - 0888-7543 .- 1089-8646. ; 106:6, s. 384-392
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Tidskriftsartikel (refereegranskat)abstract
- Previously, we reported an arsenic resistant bacterium Lysinibacillus sphaericus B1-CDA, isolated from an arsenic contaminated lands. Here, we have investigated its genetic composition and evolutionary history by using massively parallel sequencing and comparative analysis with other known Lysinibacillus genomes. Assembly of the sequencing reads revealed a genome of ~ 4.5 Mb in size encompassing ~ 80% of the chromosomal DNA. We found that the set of ordered contigs contains abundant regions of similarity with other Lysinibacillus genomes and clearly identifiable genome rearrangements. Furthermore, all genes of B1-CDA that were predicted be involved in its resistance to arsenic and/or other heavy metals were annotated. The presence of arsenic responsive genes was verified by PCR in vitro conditions. The findings of this study highlight the significance of this bacterium in removing arsenics and other toxic metals from the contaminated sources. The genetic mechanisms of the isolate could be used to cope with arsenic toxicity.
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| 6. |
- Rahman, Aminur, 1984-, et al.
(författare)
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Data in support of the comparative genome analysis of Lysinibacillus B1-CDA, a bacterium that accumulates arsenics
- 2015
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Ingår i: Data in Brief. - : Elsevier. - 2352-3409. ; 5, s. 579-585
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Tidskriftsartikel (refereegranskat)abstract
- This study is a part of our long term project on bioremediation of toxic metals and other pollutants for protection of human health and the environment from severe contamination. The information and results presented in this data article are based on both in vitro and in silico experiments. In vitro experiments were used to investigate the presence of arsenic responsive genes in a bacterial strain B1-CDA that is highly resistant to arsenics. However, in silico studies were used to annotate the function of the metal responsive genes. By using this combined study consisting of in vitro and in silico experiments we have identified and characterized specific genes from B1-CDA that can be used as a potential tool for removal of arsenics as well as other heavy metals from the contaminated environment.
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| 7. |
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| 8. |
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| 9. |
- Rahman, Aminur, et al.
(författare)
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Investigation on Arsenic-Accumulating and Arsenic-Transforming Bacteria for Potential Use in the Bioremediation of Arsenics
- 2017
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Ingår i: Handbook of Metal-Microbe Interactions and Bioremediation. - Boca Raton, FL : CRC Press. - 9781498762427 - 9781498762434 ; , s. 509-520
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Bokkapitel (refereegranskat)abstract
- In this chapter, arsenic-accumulating and arsenic- transformingbacterial strains that can be employed as a sourcefor cost-effective and eco-friendly bioremediation of arsenicsfrom contaminated environments have been reviewed. Thischapter demonstrates that many naturally occurring bacterialstrains like B1-CDA have the potential for reducing arseniccontent in contaminated sources to safe levels. Therefore,the socioeconomic impact of this kind of microorganisms ishighly significant for those countries, especially in the developingworld, where impoverished families and villages aremost impacted. Therefore, this discovery should be consideredto be the most significant factor in formulating nationalstrategies for effective poverty elimination. Besides humanarsenic contamination, these bacterial strains will also benefitlivestock and native animal species, and the outcome ofthese studies is vital not only for people in arsenic-affectedareas but also for human populations in other countries thathave credible health concerns as a consequence of arseniccontaminatedwater and foods.
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| 10. |
- Rahman, Aminur, 1984-, et al.
(författare)
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Isolation and characterization of a Lysinibacillus strain B1-CDA showing potential for bioremediation of arsenics from contaminated water
- 2014
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Ingår i: Journal of Environmental Science and Health. Part A. - : Taylor & Francis. - 1093-4529 .- 1532-4117. ; 49:12, s. 1349-1360
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of this study was to identify and isolate arsenic resistant bacteria that can be used for removing arsenic from thecontaminated environment. Here we report a soil borne bacterium, B1-CDA that can serve this purpose. B1-CDA was isolated fromthe soil of a cultivated land in Chuadanga district located in the southwest region of Bangladesh. The morphological, biochemicaland 16S rRNA analysis suggested that the isolate belongs to Lysinibacillus sphaericus. The minimum inhibitory concentration (MIC)value of the isolate is 500 mM (As) as arsenate. TOF-SIMS and ICP-MS analysis confirmed intracellular accumulation and removalof arsenics. Arsenic accumulation in cells amounted to 5.0 mg g¡1 of the cells dry biomass and thus reduced the arsenicconcentration in the contaminated liquid medium by as much as 50%. These results indicate that B1-CDA has the potential forremediation of arsenic from the contaminated water. We believe the benefits of implementing this bacterium to efficiently reducearsenic exposure will not only help to remove one aspect of human arsenic poisoning but will also benefit livestock and native animalspecies. Therefore, the outcome of this research will be highly significant for people in the affected area and also for humanpopulations in other countries that have credible health concerns as a consequence of arsenic-contaminated water.
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