•Identification of B. amyloliquefaciens by 16S rRNA gene sequencing from chromite soil.•Cr(VI) reduction potential of B. amyloliquefaciens is a first report.•Bacterium reduces 100mgL−1 of Cr(VI) in a ...faster rate of 45h under optimized set of condition.•Reduced product was characterized with SEM–EDX, Raman spectroscopy, TEM–EDX, SAED, XRD, FT-IR, AAS analyses.•Nanometric sized amorphous Cr(III) hydroxide have industrial applications.
A strain CSB 9 isolated from chromite mine soil of Sukinda, India was identified as Bacillus amyloliquefaciens based on biochemical and 16S rRNA gene sequencing. The strain exhibited relatively high tolerance to Cr(VI) (⩽900mgL−1) and fast reduction rate of 2.22mg Cr(VI) L−1h−1, under optimized conditions of 100mgL−1 Cr(VI), pH 7 and temperature 35°C within 45h. Mechanism of Cr(VI) reduction as well as nature and fate of the reduced product were studied to determine the scope of removal of reduced Cr(III) end product. AAS analyses of the culture products treated with Cr(VI) for 45h showed the distribution of Cr(III) in pellet and culture supernatant to be 37.4±1.7 and 62.6±3.4mgL−1, respectively. In SEM images, the bacterial pellets with Cr(VI) treatment appeared coagulated, rough and porous whereas the pellets without Cr(VI) treatment appeared regular, smooth and non-porous in structure. SEM–EDX of the bacterial precipitates under Cr(VI) treatment revealed immobilization of Cr(III) species on the bacterial cell surface. Further Raman spectroscopy analysis confirmed the presence of Cr(III) species, with characteristic peak at around 600cm−1. TEM–EDX study of the bacterial precipitates under Cr(VI) treatment showed intracellular deposition of Cr(III) which are in nanometric range. Further characterization of reduced product by XRD, FT-IR and SAED analyses suggested the formation of poorly crystalline end products. A Cr(VI) removal mechanism considering both the surface immobilization and intracellular accumulation of Cr(III) along with the formation of coagulated cell precipitate by living B. amyloliquefaciens was suggested.
Two highly Cr (VI) resistant fungal strains, CSF‐1 and CSF‐2, were isolated and identified as Cladosporium sp. and Penicillium sp., respectively, using 18S rRNA gene sequencing. At optimized growth ...conditions, the dead biomass of Cladosporium sp. and Penicillium sp. has removed more than 99% of the supplemented Cr(VI). The kinetic study outcomes evidenced that the present fungal Cr(VI) biosorption is best fitting with the pseudo‐first‐order model with higher R2 values (i.e., 0.70–0.95) than that of the pseudo‐second‐order kinetic model (R2 = 0.02–0.73). After analyzing the R2 values, it was observed that the Langmuir and Freundlich isotherm models best fit the Cr(VI) biosorption employing fungal biomass.
Chromite mine water with a high concentration of Cr(VI) harbors highly chromium resistant bacteria, which could benefit the mine environment and be used for economic bioremediation strategy for ...chromate polluted ecosystems. In the present investigation, eight comparatively high chromium tolerant (≥500 mg L
−1
) bacteria were isolated from water samples of the Sukinda chromite mine environment. Their morpho-biochemical and molecular (16S rRNA gene sequencing) characterization revealed that most of the bacteria belong to the members of the genus Bacillus, Lysinibacillus boronitolerens, and Alcaligenes faecalis. It was observed that all the eight bacterial isolates could reduce above 90% of Cr(VI) (p < 0.05) within 288 h. Out of these eight isolates, Alcaligenes faecalis (CWB-4) could able to reduce the maximum (99.77%) supplied Cr(VI) after 144 h, as the most efficient Cr (VI) reducing strain whereas, Licinibacillus boronitolerens (CWB-2) showed the least Cr(VI) reduction ability. The enzyme activities of the eight isolates were in the range of 0.67 to 5.07 U mL
−1
. Hence, the high chromate tolerant bacterial isolates, with Cr (VI) reducing potential isolated in the present study, could be considered promising biological agents for bioremediation of environments polluted with chromium.
Gold nanoparticles are predominantly used in diagnostics, therapeutics and biomedical applications. The present study has been designed to synthesize differently capped gold nanoparticles (AuNps) by ...a simple, one-step, room temperature procedure and to evaluate the potential of these AuNps for biomedical applications. The AuNps are capped with glucose, 2-deoxy-D-glucose (2DG) and citrate using different reducing agents. This is the first report of synthesis of 2DG-AuNp by the simple room temperature method. The synthesized gold nanoparticles are characterized with UV-Visible Spectroscopy, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED), Dynamic light scattering (DLS), and Energy-dispersive X-ray spectroscopy (SEM-EDS). Surface-enhanced Raman scattering (SERS) study of the synthesized AuNps shows increase in Raman signals up to 50 times using 2DG. 3-(4, 5-dimethylthiozol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay has been performed using all the three differently capped AuNps in different cell lines to assess cytotoxcity if any, of the nanoparticles. The study shows that 2DG-AuNps is a better candidate for theranostic application.
The present work represented first study of the spatio-seasonal distribution of the multi-elements in the suspended particulate matter (SPM) of the tropical Hooghly river estuary (HRE), eastern part ...of India. The high load of SPM (20–3460 mg/l) might have induced negative impact on the phytoplankton density. The relative abundance of the studied elements exhibited the following decreasing trend (concentration in μg/g and %): Si(26.44 ± 3.75%) > Al(7.94 ± 1.52%) > Fe(6.17 ± 1.9%) > K(3.05 ± 1.5%) > Ca(1.97 ± 1.11%) > Mg(1.57 ± 1.71%) > Na(1.45 ± 8.40%) > Mn(1273 ± 2003) > Zn(178.43 ± 130.95) > V(151.54 ± 27.13) > Cr(147.08 ± 32.21) > Cu(62.06 ± 14.03) > Ni(49.64 ± 12.09) > Pb(21.5 ± 10.45). The accumulation of Ni, Cr, Pb, and Cu is mainly controlled by the formation of Fe hydroxides along with particulate organic carbon (POC) and salinity. The average geo-accumulation index (I
geo
) and enrichment factor (EF) endorsed the substantial input of Cr (I
geo
= 0.037; EF = 1.61) and Zn (I
geo
= 0.123; EF = 2.07) from diffused pollution sources. From ecotoxicological point of view, the quality guidelines (QGs) suggested that Cr and Ni might possess frequent adverse biological effects. However, the mean probable effect level (PEL) quotient values revealed 49% probability of toxicity to the aquatic biota for five toxic elements (Cr, Ni, Cu, Zn, and Pb). The geochemical approaches, pollution indices, and statistical evaluation together revealed low to moderate contamination in the estuary. This baseline data would be beneficial in adopting proper management strategies for sustainable utilization and restoration of the water resources. The authors strongly recommend continuous systematic monitoring and installation of treatment plants for management of this stressed estuary.
The impacts of elemental pollution in sediments of freshwater bodies are of particular concern in rapidly urbanizing cities of the developing world and have been extensively studied in rivers and ...lakes. The current study is an attempt to highlight the importance of smaller waterbodies, which happen to form a natural network in cities, for assessing the contamination status of sediments. The distribution of elements (Al, Ca, Fe, K, Mg, S, Si, Ti, Ba, Mn, Sr, V, As, Cr, Cu, Ni, Pb and Zn) in sediments of 15 ponds and 6 canals was studied to understand the overall pollution status and the associated ecological risk to aquatic organisms. Geochemical indices revealed Cr, Cu, Pb and Zn to be the principal elements of concern. The mean concentration of Cr, Cu, Pb and Zn was 308, 174, 76.9 and 446 mg kg
−1
, respectively. Ecological risk assessment revealed that Cr in 86% sites, Ni in 52% sites, Cu and Zn in 28% sites and Pb in 10% sites were associated with possible ecological toxicity. The findings suggest that multielemental concentration in sediments of ponds and canals could effectively distinguish between pristine and polluted sites and suitably identify the main elements of concern to support cost-efficient waste management solutions customized to both the sites and elements of concern.
Zn stress seriously induces various toxic responses in
Withania somnifera
L., when accumulated above the threshold level which was confirmed by investigating the responses of protein, expression of ...antioxidant enzymes, and elemental profiling on accumulation of Zn. Zn was supplemented in the form of ZnSO
4
(0, 25, 50, 100, and 200 μM) through MS liquid medium and allowed to grow the
in vitro
germinated plants for 7 and 14 days. The study revealed that when the application of Zn increased, a significant reduction of growth characteristics was noticed with alterations of proteins (both disappearance and
de novo
synthesis). The activity of CAT, SOD, and GPX were increased up to certain concentrations and then declined, which confirmed through in-gel activity under different treatments. RT-PCR was conducted by taking three sets of genes from CAT (
RsCat
,
Catalase1
,
Cat1
) and SOD (
SodCp
,
TaSOD1.2
,
MnSOD
) and found that gene
RsCat
from CAT and
MnSOD
from SOD have shown maximum expression of desired genes under Zn stress, which indicate plant’s stress tolerance mechanisms. The proton-induced X-ray emission study confirmed an increasing order of uptake of Zn in plants by suppressing and expressing other elemental constituents which cause metal homeostasis. This study provides insights into molecular mechanisms associated with Zn causing toxicity to plants; however, cellular and subcellular studies are essential to explore molecule-molecule interaction during Zn stress in plants.
Microbial biodeterioration has been an important concern for concrete buildings’ durability over time. This study primarily emphasizes on the fungal biodeterioration of concrete and the effectiveness ...of silicon dioxide nanocoating on concrete in inhibiting fungal growth. A nanosilica coating was optimised and applied on concrete cube surface that was in turn infected with Aspergillus tamarii and monitored physical, mechanical, chemical as well as visual changes for a period of six months. The visual analysis included colour changes, Stereo Microscopy and Scanning Electron Microscopy (SEM) which showed a considerable change on the surface deterioration. Weight loss showed positive in all the concrete specimens (2.08% for biodeteriorated cubes and 2.13% for nanocoated cubes) whereas compressive strength that increased, 35.01% in nanocoated concrete cubes and 24.72% in biodeteriorated cubes. The chemical analysis included pH change in media, Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-Ray Fluorescence Spectroscopy (EDXRF) which showed that leaching of calcium ions from the concrete in biodeteriorated cubes was higher than that of nanocoated cubes. Altogether the efficacy of silicon oxide nanocoating against biodeterioration of concrete by Aspergillus tamarii was concluded to be positive.
•Novel analysis of restricting the growth of Aspergillus tamarii on concrete using nanosilica coating.•The pH increase in the medium of biodeteriorated concrete cubes was more than that of the nanocoated ones.•Nanosilica coating decreased the leaching of calcium ions from concrete when infected by Aspergillus tamarii.•Increase in compressive strength of concrete was observed to be the most in nanocoated cubes.
In areca nut and husk, 14 elements (As, Ca, Cd, Cl, Co, Cu, K, Mg, Mn, Na, Rb, Sb, and Zn) were determined, while 34 elements including rare earth elements were detected in the corresponding soil ...samples using instrumental neutron activation analysis and atomic absorption spectrometry methods, whereas the concentration levels of Hg in tested samples are negligible, perhaps, below the detection limits. No rare earth elements were detected in edible areca nut. The concentration levels of various essential elements and heavy elements such as As, Cd, and Cu present in areca nut are within the permissible levels, whereas Pb content is relatively higher than FAO/WHO’s permissible levels. The order of bioaccumulation index for heavy metals in areca nut was Cd > Sb > Cu > Zn ≥ Mn ≥ Co > Pb ≥ As. Bioaccumulation index values are indicating that areca palm may not be able to accumulate other heavy elements in the edible areca nut, except for Cd. On the basis of pollution indices, Northeast Indian soil may be relatively unpolluted.
Saraca asoca
is an important plant species of India having variety of medicinal activity such as antiviral, anti-diabetic, antimicrobial, anti-inflammatory, anti-cancer etc. Indian Kala-azar (KA) or ...visceral leishmaniasis (VL) is a protozoan parasitic disease caused by
Leishmania
sp and is endemic in Indian subcontinent. VL mainly targets the poorest people who have been suffering from deficiency in protein, nutrients and essential trace elements which ultimately leads to immunodeficiency. Essential trace element, Zinc (Zn) controls multiple aspects of innate and adaptive immunity while Iron (Fe) is required for various cellular activities. Bromine (Br) is important for assembly of collagen IV scaffolds in tissue development and helps in signalling and Copper (Cu) performs several functions related to immune system. Intra-cardiac blood was collected from the experimental BALB/c mice groups including (a) healthy control, (b) infected control, (c)
Saraca asoca
seed extract (Sa-SE) treated groups. The trace elements level in blood of mice was measured by Energy Dispersive X-Ray Fluorescence technique. Interestingly, the decreased level of Zn, Fe and Br as well as increased level of Cu in diseased state came back to almost normal range upon treatment with Sa-SE. The trace elements imbalances thus were almost restored to normalcy by treating the experimental BALB/c mice with ethanolic seed extract of
Saraca asoca
.
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