scholarly journals In vivo and in vitro studies on heavy metal tolerance in Sesbania grandiflora L

2009 ◽  
Vol 3 (2) ◽  
pp. 48-64
Author(s):  
Kadhim M. Ibrahim ◽  
Shaimaa A. Yousir

Several experiments were carried out to study heavy metal tolerance in tissue cultures or whole plants of S. grandiflora., Callus was induced and maintained on modified Murashige and Skoog, 1962 medium (MS) supplemented with (0.5)mg/l benzyl adenine and (2)mg/l 2,4-phenoxy acetic acid . Heavy metals (Cd, Co, Cu, Cr or Zn) were added to the culture medium at different concentrations as contamination agents. In order to asses the effect of these heavy metals on seed germination; seeds were sown in soil contaminated with different concentrations of heavy metals for 3 weeks. Atomic Absorption Spectrophotometer was used for analysis of samples taken from whole plants and callus cultures. Results showed that callus fresh weight decreased with increasing heavy metal concentration in cultural medium. Germination percentages and plant heights increased over time. However, a reduction occurred in these parameters with increasing heavy metal levels. Percentages of metals accumulated in calli were (0.001, 0.011, 0.012 and 0.013%) at (0.0, 0.05, 0.075 and 0.1)mg/l Cd respectively; (0.001, 0.008, 0.016 and 0.006%) at (0.0, 0.1, 0.25 and 0.5)mg/l Co respectively; (0.001, 0.020, 0.034 and 0.015%) at (0.0, 0.075, 0.2 and 0.5)mg/l Cu respectively; (0.001, 0.013, 0.012 and 0.010%) at (0.0, 0.25, 0.4 and 0.5)mg/l Cr respectively and (0.027, 0.051, 0.059 and 0.056%) at (0.0 , 0.75, 1.0 and 1.5)mg/l Zn respectively. Percentages of metals accumulated in whole plants were (0.08, 0.55, 1.11, 0.83 and 0.44%) at (0.0, 1.0, 2.0, 3.0 and 4.0)mg/Kg soil Cd respectively; (0.11, 0.22, 0.55, 0.47 and 0.44%) at (0.0, 15.0, 30.0 45.0 and 60.0)mg/Kg soil Co respectively; (0.01, 0.10, 0.57, 0.58 and 0.72%) at (0.0, 25.0, 50.0, 75.0 and 100.0)mg/Kg soil Cu respectively. (0.08, 0.80, 1.28, 1.31 and 0.88%) at (0.0, 25.0, 50.0, 75.0 and 100.0)mg/Kg soil Cr respectively and (0.06, 1.11, 1.20, 1.83 and 2.22%) at (0.0, 100.0, 200.0, 300.0 and 400.0)mg/Kg soil Zn respectively.

2002 ◽  
Vol 184 (18) ◽  
pp. 5027-5035 ◽  
Author(s):  
Liu Tong ◽  
Susumu Nakashima ◽  
Mineo Shibasaka ◽  
Maki Katsuhara ◽  
Kunihiro Kasamo

ABSTRACT A novel gene related to heavy-metal transport was cloned and identified from the filamentous cyanobacterium Oscillatoria brevis. Sequence analysis of the gene (the Bxa1 gene) showed that its product possessed high homology with heavy-metal transport CPx-ATPases. The CPC motif, which is proposed to form putative cation transduction channel, was found in the sixth transmembrane helix. However, instead of the CXXC motif that is present in the N termini of most metal transport CPx-ATPases, Bxa1 contains a unique Cys-Cys (CC) sequence element and histidine-rich motifs as a putative metal binding site. Northern blotting and real-time quantitative reverse transcription-PCR showed that expression of Bxa1 mRNA was induced in vivo by both monovalent (Cu+ and Ag+) and divalent (Zn2+ and Cd2+) heavy-metal ions at similar levels. Experiments on heavy-metal tolerance in Escherichia coli with recombinant Bxa1 demonstrated that Bxa1 conferred resistance to both monovalent and divalent heavy metals. This is the first report of a CPx-ATPase responsive to both monovalent and divalent heavy metals.


2019 ◽  
Vol 16 (1) ◽  
pp. 01-13 ◽  
Author(s):  
Pragya Goyal ◽  
Pranoti Belapurkar ◽  
Anand Kar

Microbial assisted remediation is the ray of hope in the current scenario of tremendous heavy metal pollution. The indiscriminate release of heavy metal laden industrial effluents in the water bodies and soil is now manifesting itself in the form of life threatening health hazards to humans. The conventional heavy metal remediation strategies are not only expensive but are ineffective in low metal concentrations. Microbial assisted remediation of heavy metals has come forward as the cheap and easy alternative. Amongst the various bacterial genera actively involved in bioremediation of cadmium and nickel in the environment, genus Bacillus has shown remarkable ability in this respect owing to its various biochemical and genetic pathways. It can perform bioremediation using multiple mechanisms including biosorption and bioaccumulation. This genus has also been able to reduce toxicity caused by cadmium and nickel in eukaryotic cell lines and in mice, a property also found in probiotic genera like Lactobacillus and Bifidobacterium. This paper reviews the role of environmentally present and known probiotic species of genus Bacillus along with different probiotic genera for their various mechanisms involved for remediation of cadmium and nickel.


Author(s):  
Muibat Fashola

Introduction: Indiscriminate dumping of spent oils enriched with heavy metals has led to increase in heavy metals load in the soil. Heavy metals exert toxic effects on biodegradation of organic pollutant in cocontaminated soil and there is need to find suitable strategies for their removal. Aim: The aim of this study was to assess the heavy metals resistance capability of indigenous Bacillus species in hydrocarbon polluted soil to nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Materials and Methods: Heavy metal tolerant bacteria were isolated from hydrocarbon polluted soil using Luria-Berthani agar supplemented with the respective metals and spread plate techniques. The isolates were putatively identified on the basis of their colonial morphology and biochemical characteristics and their antibiotics susceptibility pattern were evaluated using disc diffusion method. Results: The maximum tolerable concentration (MTC) of the four heavy metals to the selected isolates was 2 mM. Four bacteria isolates able to withstand the MTC were putatively identified as Bacillus subtilis, Bacillus megaterium, Bacillus laterosporus and Bacillus polymyxa. Out of the four Bacillus species, only B. laterosporus did not show multiple tolerance to the tested antibiotics which show that there is correlation between heavy metal tolerance and antibiotics resistance by the isolates. Conclusion: Multiple heavy metal tolerance Bacillus spp. were isolated from crude oil polluted soil. These bacteria could be suitable agents for bioaugmentation of hydrocarbon polluted soil co-contaminated with heavy metals.


Biologia ◽  
2012 ◽  
Vol 67 (5) ◽  
Author(s):  
Kamala Gupta ◽  
Chitrita Chatterjee ◽  
Bhaskar Gupta

AbstractThe present study was conducted to determine the culturable bacterial profile from Kestopur canal (Kolkata, India) and analyze their heavy metal tolerance. In addition to daily sewage including solid and soluble wastes, a considerable load of toxic metals are released into this water body from industries, tanneries and agriculture, household as well as health sectors. Screening out microbes from such an environment was done keeping in mind their multifunctional application especially for bioremediation. Heavy metals are major environmental pollutants when present in high concentration in soil and show potential toxic effects on growth and development in plants and animals. Some edible herbs growing in the canal vicinity, and consumed by people, were found to harbour these heavy metals at sub-toxic levels. The bioconcentration factor of these plants being <1 indicates that they probably only absorb but not accumulate heavy metals. All the thirteen Grampositive bacteria isolated from these plants rhizosphere were found to tolerate high concentration of heavy metals like Co, Ni, Pb, Cr, Fe. Phylogenetic analysis of their 16S rDNA genes revealed that they belonged to one main taxonomic group — the Firmicutes. Seven of them were found to be novel with 92–95% sequence homology with known bacterial strains. Further microbiological analyses show that the alkaliphilic Bacillus weihenstephanensis strain IA1 and Exiguobacterium aestuarii strain CE1, with selective antibiotic sensitivity along with high Ni2+ and Cr6+ removal capabilities, respectively, can be prospective candidates for bioremediation.


Heavy metals are the most important pollutants that are non-biodegradable and increasingly accumulate in the environment. Phytoremediation can be defined as the use of plants for the extraction, immobilization, containment, or degradation of contaminants. It provides an ecologically, environmentally sound and safe method for restoration and remediation of contaminated land. Plant species vary in their capacity of hyper-accumulation of heavy metals. The chapter reviews the current findings on the molecular mechanism involved in heavy metals tolerance, which is a valuable tool for phytoremediation. The heavy metal tolerance genes help in the hyper-accumulation trait of a plant. Heavy metal transporter ATPases (HMAs) genes help in the refluxing of heavy metal ions from the cytosol, either into the apoplast, the vacuole, or other organelles, which help in the hyperaccumulation of metal. Understanding the signaling mechanism of transporter genes will be an important tool to understand the genetics of hyperaccumulation.


Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 896 ◽  
Author(s):  
Shafaqat Ali ◽  
Zohaib Abbas ◽  
Mahmoud F. Seleiman ◽  
Muhammad Rizwan ◽  
İlkay YAVAŞ ◽  
...  

Unexpected biomagnifications and bioaccumulation of heavy metals (HMs) in the surrounding environment has become a predicament for all living organisms together with plants. Excessive release of HMs from industrial discharge and other anthropogenic activities has threatened sustainable agricultural practices and limited the overall profitable yield of different plants species. Heavy metals at toxic levels interact with cellular molecules, leading towards the unnecessary generation of reactive oxygen species (ROS), restricting productivity and growth of the plants. The application of various osmoprotectants is a renowned approach to mitigate the harmful effects of HMs on plants. In this review, the effective role of glycine betaine (GB) in alleviation of HM stress is summarized. Glycine betaine is very important osmoregulator, and its level varies considerably among different plants. Application of GB on plants under HMs stress successfully improves growth, photosynthesis, antioxidant enzymes activities, nutrients uptake, and minimizes excessive heavy metal uptake and oxidative stress. Moreover, GB activates the adjustment of glutathione reductase (GR), ascorbic acid (AsA) and glutathione (GSH) contents in plants under HM stress. Excessive accumulation of GB through the utilization of a genetic engineering approach can successfully enhance tolerance against stress, which is considered an important feature that needs to be investigated in depth.


2015 ◽  
Vol 1130 ◽  
pp. 263-267 ◽  
Author(s):  
Hee Chan Jang ◽  
Marjorie Valix

In this study, the adaptation of A. thiooxidans to heavy metals leached from saprolitic Ni laterite ores was performed by gradual acclimatisation. The bacteria was cultivated in heavy metals (Ni, Co, Fe, Mg, Cr and Mn) with total concentrations of 2400 to 24000 ppm equivalent to total dissolution of 1 to 10% (w/v) pulp densities of the saprolitic Ni laterite ore. Adaptation evolution mapped from its tolerance index was found to be dependent on metal concentration, acid generation, and period of adaptation. Bio-stimulation of cell growth and acid production was promoted by heavy metal stress on the bacteria. Pre-established heavy metal tolerance of the bacteria improved the leaching rate in its early phase; 20% and 7% increase in Ni and Co metal recoveries were observed in using adapted bacteria. However heavy metal tolerance was also achieved by the bacteria during the leaching process, albeit delayed by a lag phase. These results confirm the robust nature and suitability of A. thiooxidans in direct biomining of Ni ores.


2010 ◽  
Vol 32 (3) ◽  
pp. 527-533 ◽  
Author(s):  
Iva Smykalova ◽  
Miroslava Vrbova ◽  
Eva Tejklova ◽  
Martina Vetrovcova ◽  
Miroslav Griga

2016 ◽  
Vol 30 (1-2) ◽  
pp. 17-22 ◽  
Author(s):  
Tahmina Shammi ◽  
Sangita Ahmed

Pollution of the environment with toxic heavy metals is spreading throughout the world along with industrial progress. Removal of these toxic heavy metals by using bacteria has achieved growing attention in recent years. The present study focuses on isolation of lead and chromium tolerant Bacillus spp., from the Buriganga and the Shitalkhya, the two major rivers surrounding Dhaka. A total of 25 Bacillus spp. isolates tolerant to 50 ppm lead and chromium were preliminarily identified based on morphological and biochemical analysis. Further investigation revealed that all isolates were also able to grow at 1000 ppm lead and 400 ppm chromium, while tolerance to 1500 ppm lead and 500 ppm chromium was observed among 48% and 76% isolates, respectively. All isolates were also able to grow at 50 ppm copper and 50 ppm zinc, while 72% grew at 100 ppm copper. The heavy metal tolerant Bacillus spp were also multi drug resistant and showed resistance to Tetracycline (100%), Ceftazidime (100%), Ceftriaxone (100%), Ampicillin (28%) and Nalidixic acid (24%).Bangladesh J Microbiol, Volume 30, Number 1-2,June-Dec 2013, pp 17-22


Sign in / Sign up

Export Citation Format

Share Document