ARTICLE | doi:10.20944/preprints202209.0064.v2
Subject: Biology, Physiology Keywords: Antarctica; antioxidants; cadmium; copper; fish; metallothioneins
Online: 6 October 2022 (09:57:16 CEST)
Metal bioaccumulation and metallothionein (MT) expression were investigated in gills and liver of the red-blooded Antarctic teleost Trematomus hansoni with the aim to evaluate the possibility for this species to face, with adequate physiological responses, an increase of copper or cadmium concentrations in the environment. Specimens of this Antarctic fish were collected from Terra Nova Bay (Ross Sea) and used for a metal exposure experiment in controlled laboratory condi-tions. The two treatments lead to a significant accumulation of both metals and an increase of gene transcription only for the MT-1. The biosynthesis of MTs was verified especially in speci-mens exposed to Cd, but the majority of these proteins were soon oxidized, probably because they were involved in cell protection against the risk of oxidative stress, by reactive oxygen spe-cies scavenging. The obtained data highlighted the phenotypic plasticity of T. hansoni, a species evolved in an environment characterized by natural high concentrations of Cu and Cd, and maybe the possibility for the Antarctic fish to face the challenges of a world that is becoming every day more toxic.
ARTICLE | doi:10.20944/preprints201610.0022.v1
Subject: Biology, Animal Sciences & Zoology Keywords: P. pseudoannulata; Cadmium; Transcriptome; RT-qPCR
Online: 8 October 2016 (11:07:25 CEST)
Pardosa pseudoannulata is one of the most common wandering spiders in agricultural fields and a potentially good bioindicator for heavy metal contamination. However, little is known about the mechanism by which spiders respond to heavy metals at the molecular level. In this study, high-throughput transcriptome sequencing was employed to characterize the de novo transcriptome of the spiders and to identify differentially expressed genes (DEGs) after cadmium exposure. We obtained 60,489 assembled unigenes, 18,773 of which were annotated in the public databases. Ultimately, 3450 cDNA simple sequence repeats were identified and validated as potential molecular markers in the unigenes. A total of 2939, 2491 and 3759 DEGs were detected among the three libraries of two Cd-treated groups and the control. Functional enrichment analysis revealed that metabolism processes and digestive system function were predominately enriched in response to Cd stress. At the cellular and molecular levels, significantly enriched pathways in lysosomes and phagosomes as well as replication, recombination and repair demonstrated that oxidative damage resulted from Cd exposure. Based on the selected DEGs, certain critical genes involved in defence and detoxification were analysed. These results may elucidate the molecular mechanism underlying spiders' responses to heavy metal stress.
ARTICLE | doi:10.20944/preprints202106.0720.v1
Subject: Arts & Humanities, Anthropology & Ethnography Keywords: Biochar; Cadmium; Pyrolysis temperature; Adsorption kinetics; Desorption
Online: 30 June 2021 (09:10:01 CEST)
Biochar has high potential usage in retaining various contaminants, wastewater treatment, and water purification. In this study, three rice husk derived biochars with pyrolysis temperature 300, 400 and 500 ºC, respectively, and pristine rice rusk were used to remove cadmium from aqueous solution. The results showed that about 70% or more of Cd2+ adsorption occurred in the first 960 mins of adsorption kinetics. The Cd2+ adsorption capacity under equilibrium increased with increasing pyrolysis temperature, probably attributed to the increased specific surface area (SSA) under higher pyrolysis temperature noting that significant linear correlation occurred between Cd2+ adsorption capacity and SSA. The Cd2+ adsorption could be best fitted by pseudo-second order model relative to Elovich model and pseudo-first order model. The Cd2+ adsorption rates were higher in ﬁlm diffusion stage, indicating that ﬁlm diffusion stage was signiﬁcant and fast in the early stage of Cd2+ adsorption. In contrast, Cd2+ adsorption by intra-particle diffusion accounted for 47.0%, 47.9% and 43.9% on average of the total Cd2+ adsorption, respectively, indicating that intra-particle diffusion of Cd2+ played a more predominant role in limiting Cd2+ adsorption rate. When reaching Cd2+ desorption equilibrium, removal ratio (RR) values were averaged 0.96, 0.91, and 0.90 under three initial concentrations. More than 90 percentage on average of Cd2+ was removed from aqueous solution by biochars and rice rusk as well, thus biochars can be used to efficiently remove contaminants from aqueous environment. Cation exchange, electrostatic attraction, and the complexation with surface functional groups could be the main dominant mechanisms for Cd2+ adsorption-desorption on biochars.
ARTICLE | doi:10.20944/preprints202007.0339.v1
Subject: Earth Sciences, Environmental Sciences Keywords: cocoa seed; cocoa beans; heavy metals; Cadmium
Online: 16 July 2020 (04:09:54 CEST)
The presence of heavy metals in cocoa crops is currently a serious problem for farmers and producers in various regions of Peru. Exports of cocoa and its derivatives to European markets are threatened by possible indications of contamination of heavy metals such as Cadmium (Cd) in cocoa beans for export, some at levels higher than those allowed by food regulations established by European Community, which are oriented to consumer protection. The possible sources of cadmium contamination in cocoa crops can be due to natural activities, such as volcanic activities, erosion processes and sedimentation in rocks that contain minerals with a high content of heavy metals (Greenockite, Burnsite, Hawleite, among others), and by anthropogenic activities such as: mining of associated deposits, agriculture (use of fertilizers), smelting of minerals and burning of fossil fuels. Currently, there is no information about contents of heavy metals in areas located in The Campo Verde-Honoria-Tournavista corridor (Ucayali Region and Huanuco Region), due to this, in this work we make a study of this region. A methodology will be used to take cocoa samples from the seed and soil in these areas, and then through chemical analysis, determine the concentrations of heavy metals, using an atomic absorption spectrophotometer. As a consequence of this study, we determined and concluded that the concentrations of cadmium obtained in soils are slightly higher than European standards allowed. Therefore, with this information we prepare a geochemical cadmium map in soils for the study area, which will help cocoa producers to identify areas that exceed the allowed cadmium values, in order to comply with standards that European Community demands in relation of concentration levels of heavy metals (Cadmium) in chocolate. In this way, we can carry out in the future a mitigation plan for areas with cadmium problems, which allows to reduce their content in order to export the product without any problem. .
ARTICLE | doi:10.20944/preprints201803.0133.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: hypertension; lead; cadmium; blood pressure; combined exposure
Online: 16 March 2018 (07:22:57 CET)
We evaluated the association of blood pressure with blood levels of cadmium, lead, and cadmium and lead together (cadmium+lead) in a representative sample of adolescents from Korea by use of 2010-2016 data from the Korean National Health and Nutrition Examination Survey (KNHANES). This cross-sectional study enrolled adolescents aged at 10-18 years-old who completed a health examination survey and had blood measurements of lead and cadmium. The association of adjusted mean differences in diastolic and systolic blood pressure with doubling of blood lead and cadmium were estimated by regression of blood pressure against log2-transformed blood metals and their quartiles after covariate adjustment. Adjusted odds ratios for prehypertension were calculated for log2-transformed blood levels of lead and cadmium and their quartiles. Our analysis of adolescents in Korea indicated that blood levels of lead and cadmium were not significantly associated with increased blood pressure or risk of pre-hypertension. However, the cadmium+lead level was associated with pre-hypertension. Previous studies showed that blood levels of lead and cadmium were associated with increased blood pressure and risk of hypertension in adult populations. We found no such effect in Korean adolescents, although the cadmium+lead level was associated with prehypertension. These differences may be because adolescents generally have lower levels of these blood metals or because adolescents only rarely have hypertension.
ARTICLE | doi:10.20944/preprints202208.0185.v1
Subject: Life Sciences, Other Keywords: fungal systematics; Talaromyces santanderensis; cadmium; cacao rhizosphere; mycoremediation
Online: 10 August 2022 (03:29:20 CEST)
Inorganic pollutants in Colombian cocoa (Theobroma cacao L.) agrosystems cause problems in the production, quality, and exportation of this raw material. There has been an increased interest in bioprospecting studies of different fungal species focused on the biosorption of heavy metals. Furthermore, fungi constitute a valuable, profitable, ecological, and efficient natural soil resource that could be considered in the integrated management of cadmium mitigation. In this study, we report a new species of Talaromyces, isolated from cocoa soil from San Vicente de Chucurí-Colombia. The characterization of the culture was performed on six different standardized media and was distinguished by characteristic colony morphology: biverticillate and monoverticillate penicilli, acerose phialides, and slightly globose smooth-walled conidia. Culture was featured by bright yellow mycelium in young culture on CYA and CYAS medium. Colonies grew faster on Malt and Oat agar, attaining 36 and 32 mm diameter after seven days at 20 ºC. High acid production on CREA medium at 20-30 ºC was observed. Phylogenetic analysis was based on the ITS region and the RPB2, Calmodulin (CaM) and β-Tubulin genes that indicate that it is new to science and is named Talaromyces santanderensis sp. nov. This new species belongs to the Talaromyces section and is closely related to T. lentulus and related to T. soli, T. tumuli and T. pratensis (inside the T. pinophilus species complex) in the inferred phylogeny. Mycelia growth of the fungal strains was subjected to a range of 0-400 ppm Cd and incorporated into malt extract agar (MEA) in triplicates. Fungal radial growth was recorded every three days over a 13-days incubation period and In vitro cadmium tolerance tests showed a high tolerance index = 0,81 when the mycelium was exposed to 300 ppm of Cd. Results suggest T. santanderensis showed tolerance to Cd concentrations that exceed the permissible limits for contaminated soils, and it is promising for its use in bioremediation strategies to eliminate Cd from highly contaminated agricultural soils.
ARTICLE | doi:10.20944/preprints202009.0731.v1
Subject: Chemistry, Analytical Chemistry Keywords: Cosmetic, Heavy metals, Toxicity, Cadmium, Atomic Absorption Spectroscopy.
Online: 30 September 2020 (09:07:14 CEST)
Throughout the ages and times, the need to use everything that reflects women's beauty and helps them maintain their vision and health, and if the need to use the precious materials has been put in place, it is important that they produce the desired results without attention to the harmful chemicals and heavy metals that they contain. Over time, the toxicity of these heavy metals increases in our environment because of their long-term exposure to these pollutants, whether low or high-level in toxicity, animal-prednmost, environment, including air we breathe, water, food, etc. Cosmetics are one of these sources through which humans are exposed to heavy toxic metals. Heavy metals have been estimated in a number of previous studies, and in our study here, we aim to estimate the amount of cadmium metal and study it in various cosmetics such as Lipstick, Eye shadow, Face whitening cream. Two samples were taken from each of the locomoys and cadmium was estimated using the photometer of atomic absorption, one of the samples being expensive and the other low-cost, and purchased from the wholesale markets of Taiz City. Cadmium has been found prominently in these products and the highest rate found in the lowest cost-effective, Eye shadow, that the use of these cosmetic products exposes users to low- conc. heavy metals, which may pose a danger to their health. They are known to be clustered in their biological systems over time, resulting in an imbalance of body and environment. The results found that the low-priced color samples contained a higher concentration of cadmium than the high-price samples in low-priced samples, cadmium concentration was in order of eye shadow > lipstick = face whitening cream. The similar pattern are shown also for higher price product, which are lipstick > face whitening cream > eye shadow.
ARTICLE | doi:10.20944/preprints201802.0075.v1
Subject: Biology, Plant Sciences Keywords: OsCd1; Cadmium accumulation; rice grain; indica; japonica; GWAS
Online: 9 February 2018 (07:13:17 CET)
Cadmium accumulation in rice grain poses a serious threat to people’s health. Understanding the genetic basis on grain cadmium accumulation facilitates efforts to reduce it. Here, we show that OsCd1 is involved in Cd uptake and contributes to grain accumulation in rice. Natural variation in OsCd1 with a missense mutation Val449Asp is responsible for the divergence of rice grain cadmium accumulation between japonica and indica. Notably, near-isogenic line tests confirmed that the indica variety carrying the OsCd1V449 allele could reduce the grain cadmium accumulation. The favorable allele OsCd1V449 may be an important genetic resource to reduce grain cadmium accumulation for indica.
ARTICLE | doi:10.20944/preprints202109.0331.v1
Subject: Chemistry, Applied Chemistry Keywords: Adsorption; DFT; Cadmium(II) ion; Activated carbon; Kinetics; Thermodynamics
Online: 20 September 2021 (12:22:22 CEST)
Cadmium(II) contamination in the environment is an emerging problem due to its acute toxicity and mobility, so it is very urgent to remove this species from industrial wastewater before it is discharged into the environment. Thus, a starch-based activated carbon (AC) with a specific surface area of 1600 m2g-1 is used as an adsorbent for the capturing of toxic cadmium(II) ions from synthetic solutions. The sorbent is characterized by BET, SEM, TEM, XRD, FT-IR, TGA, and zeta potential. The maximum uptake (284 mg g-1) of Cadmium(II) ion is obtained at pH 6. The thermodynamic parameters like ∆G, ∆H, ΔS are found to be -17.42 kJmol-1, 6.49 kJ mol-1, and 55.66 Jmol-1K-1 respectively, revealing that the adsorption mechanism is endothermic, spontaneous, and feasible. The experimental data follows the D-R and Langmuir models well. The mass transfer is controlled by pseudo 2nd order kinetics. Furthermore, the density functional theory simulations demonstrate that the activated carbon strongly interacted with the Cd(II) ion through its various active sites. The adsorption energy noted for all interactive sites is highly negative (-0.45 eV to -10.03 eV), which shows that the adsorption process is spontaneous and stable which is in agreement with the experimental thermodynamics analysis.
ARTICLE | doi:10.20944/preprints201808.0082.v1
Subject: Earth Sciences, Environmental Sciences Keywords: mine waste; lead; zinc; cadmium; microbial role; sulfur-reducing bacteria
Online: 4 August 2018 (11:07:24 CEST)
Milling and mining metal ores are major sources of heavy metal contamination. The Spring River and its tributaries in southeast Kansas are contaminated with Pb, Zn, and Cd as a result of 120 years of mining activities. Trace metal transformations and cycling in mine waste materials greatly influence their mobility and toxicity and affect plant productivity and human health. It has been hypothesized that under reduced conditions in sulfate-rich environments, these metals can be transformed into their sulfide forms, thus limiting mobility and toxicity. We studied biogeochemical transformations of Pb, Zn and Cd in flooded subsurface mine waste materials, natural or treated with organic carbon (OC) and/or sulfur (S), by combining advanced microbiological and X-ray spectroscopic techniques to determine the effects of treatments on the microbial community structure and identify the dominant functional genes involved in the biogeochemical transformations, especially metal sulfide formation over time. Samples collected from medium-, and long-term submerged columns were used for microarray analysis via functional gene array (GeoChip 4.2). The total number of detected gene abundance decreased under long-term submergence, but major functional genes abundance was enhanced with OC plus S treatment. The microbial community exhibited a substantial change in structure in response to OC and S addition. Sulfur-reducing bacteria genes dsrA/B were identified as key players in metal sulfide formation via dissimilatory sulfate reduction. Uniqueness of this study is that microbial analyses presented here in details are in agreements with molecular-scale synchrotron-based X-ray data supporting that OC-plus-S treatment would be a promising strategy for reducing metal toxicity in mine waste materials.
ARTICLE | doi:10.20944/preprints201811.0160.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Aronia melanocarpa berries; cadmium; liver; oxidative/antioxidative balance; oxidative stress; protection
Online: 7 November 2018 (10:47:33 CET)
The study investigated, in a rat model of low-level and moderate environmental exposure to cadmium (Cd; 1 or 5 mg Cd/kg diet, respectively, for 3-24 months), whether the co-administration of 0.1% extract from Aronia melanocarpa L. berries (AE) may protect against oxidative stress in the liver. The intoxication with Cd, dose- and duration-dependently, weakened the enzymatic antioxidative barrier (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase), decreased the concentrations of non-enzymatic antioxidants (reduced glutathione and total thiol groups), and increased the concentrations of oxidized glutathione, hydrogen peroxide, xanthine oxidase, and myeloperoxidase in this organ. These resulted in a decrease in the total antioxidative status (TAS), an increase in the total oxidative status (TOS), and development of oxidative stress in the liver (evaluated based on the index of oxidative stress calculated as the ratio of TOS and TAS). The administration of AE at both levels of Cd treatment significantly improved the enzymatic and non-enzymatic antioxidative barrier, decreased the concentration of pro-oxidants, and protected from the development of oxidative stress in the liver. In conclusion, consumption of aronia products may prevent Cd-induced destroying the oxidative/antioxidative balance and development of oxidative stress in the liver protecting against this organ damage.
REVIEW | doi:10.20944/preprints202111.0300.v1
Subject: Medicine & Pharmacology, Other Keywords: Endocrine disruptors; gender; female; atherosclerosis; Cadmium; Bisphenol A; inflammatory cytokines; cardiovascular diseases
Online: 17 November 2021 (10:53:12 CET)
The number of aged individuals is increasing worldwide, rendering essential the comprehension of pathophysiological mechanisms of age-related alterations, that could facilitate the development of interventions contributing to “successful aging” and improvement of quality of life. Cardio-vascular diseases (CVD) include pathologies affecting heart or blood vessels, such as hyperten-sion, peripheral artery disease and coronary heart disease. Indeed, age-associated modifications in body composition, hormonal, nutritional and metabolic factors, as well as a decline in physical activity are all involved in the increased risk of developing atherogenic alterations raising the risk of CVD development. Several factors have been claimed to play a role in the alterations observed in muscle and endothelial cells and leading to increased CVD, such as genetic pattern, smoking, unhealthy lifestyle. Moreover, a difference in the risk of these diseases in women and men has been reported. Interestingly, in the last decades attention has been focused on a potential role of several pollutants which disrupt human health by interfering with hormonal pathways, and more specifically in non-communicable diseases such as obesity, diabetes and CVD. This review will focus on the potential alteration induced by Endocrine Disruptors (Eds) in the attempt to characterize a potential role in the cellular and molecular mechanisms involved in the atheromatic process and CVD progression.
ARTICLE | doi:10.20944/preprints202009.0642.v1
Subject: Life Sciences, Biochemistry Keywords: copper; mercury; cadmium; oxidative stress; protein carbonylation; translation factors; oxidative stress biomarkers
Online: 26 September 2020 (14:46:39 CEST)
The impact of metals bioaccumulation on marine organisms is under investigation. This study was designed to determine the association of oxidative stress in mussels Mytilus galloprovincialis induced by seawater enriched with trace metals with protein synthesis. Mussels were exposed to 40 μg/L Cu, 30 μg/L Hg, or 100 μg/L Cd for 5 and 15 days, and the pollution effect was evaluated by measuring established oxidative biomarkers. The results showed damage on the protein synthesis machine integrity and specifically, on translation factors and ribosomal proteins expression and modifications. Exposure of mussels to all metals caused oxidative damage that was milder in the cases of Cu and Hg, and more pronounced for Cd. However, after prolonged exposure of mussels to Cd (15 days), the effects receded. These changes that perturb protein biosynthesis can serve as a great tool for elucidating the mechanisms of toxicity and could be integrated in biomonitoring programs.
ARTICLE | doi:10.20944/preprints202007.0235.v1
Subject: Biology, Physiology Keywords: cadmium; glutathione; glutathione reductase; malondialdehyde; metallothionein; Mytilus galloprovincialis; oxidative stress; ROS scavenging
Online: 11 July 2020 (09:26:12 CEST)
Exposure to metals is known to generate oxidative stress in living organisms, which are able to respond with the induction of antioxidant defenses, both enzymatic and non-enzymatic. The aim of this work is to study the correlation among several non-enzymatic component of the antioxidant system, that are physiologically related to both metal sequestration and defense against metal-induced oxidative stress, using the blue mussels (Mytilus galloprovincialis) as model organism. Specimens of this marine bivalve were experimentally exposed to cadmium (Cd), used as oxidative stress risk inducer. Cd, metallothionein (MT), glutathione (GSH), malondialdehyde (MDA) contents, and glutathione reductase (GR) activity in gills and in digestive glands were assessed at 0, 12, 24, 48, 72 and 96 h. The obtained results provide new data about the relationships among the non-enzymatic antioxidant cellular components considered in this study. These constitute the prompt physiological responses to the risk of oxidative stress in blue mussels exposed to Cd in controlled laboratory conditions.
ARTICLE | doi:10.20944/preprints201908.0235.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: endophytic bacteria; indole-3-acetic acid; cadmium accumulation; phosphate solubilization; reduced glutathione
Online: 23 August 2019 (04:06:54 CEST)
Cadmium (Cd) is a heavy metal that suppresses plant growth; however, application of endophytic bacteria can increase resistance of plants against Cd, as well as improve plant growth. Two bacterial endophytic strains were isolated from Solanum nigrum and were identified as Serratia sp. AI001 and Enterobacter sp. AI002 by 16S DNA sequencing. Strains AI001 and AI002, tolerated up to 25 mg/mL Cd in broth culture and showed phosphate solubilization potential in Pikovskaya agar medium. AI001 and AI002 produced indole-3-acetic acid, which was confirmed by gas spectrometry-mass chromatography. Brassica plants stressed with 0, 5, 15, and 25 mg/L Cd showed significant decrease in plant growth, chlorophyll content and biomass, and significant increase in Cd dose-dependent electrolyte leakage. Inoculation of strain AI001 or AI002 significantly enhanced the plant growth attributes of shoot length, root length, chlorophyll content, and biomass as compared to those in uninoculated plants. Reduced glutathione contents in plants stressed with different concentrations of Cd also increased with inoculation of AI001 and AI002. The reason of Cd resistance enhancement in plants by inocula could be due to their greater plant growth promoting activities as well as their antioxidative response.
ARTICLE | doi:10.20944/preprints201901.0295.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: topological insulator; phase transition; mercury cadmium telluride; Landau levels; magneto-absorption; magnetotransport
Online: 29 January 2019 (16:44:14 CET)
We report on comparison between temperature-dependent magneto¬absorption and magnetotransport spectroscopy of HgTe/CdHgTe quantum wells in terms of detection of phase transition between topological insulator and band insulator states. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases, yet magnetotransport method is shown to have advantages for clear manifestation of the phase transition with accurate quantitative values of transition parameter (i.e. critical magnetic field Bc).
ARTICLE | doi:10.20944/preprints201806.0487.v2
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: bio-accessibility; 24-h diet; preschool children; arsenic intake; cadmium intake; lead intake
Online: 6 October 2018 (11:02:24 CEST)
Lead, known as a metal with high neurotoxicity to children, cadmium, which is a carcinogenic and bioaccumulative contaminant, and arsenic, a class 1 carcinogenic according to the International Agency for Research on Cancer, are toxic elements (TEs) whose relevant route of exposure may be diet. We determined the bio-accessible fraction of lead, cadmium, and arsenic from the diet of preschool children from two day care centers (DCC). A cross-sectional study was conducted with 64 one–four-year-old children from two DCCs where the 24-h duplicate diet samples were collected. The diet samples were analyzed by ICP-MS for lead, cadmium, and arsenic total concentrations (n = 64) and their bio-accessibility were analyzed for a subsample (n = 10). The dietary intake (DI) mean for lead, cadmium, and arsenic were 0.18 ± 0.11 µg kg−1 bw, 0.08 ± 0.04 µg kg−1 bw, and 0.61 ± 0.41 µg kg−1 bw, respectively. All DI calculated for TEs, considering total intake, were found lower than the tolerable limits (TL) (European Union, or World Health Organization, WHO, when applicable) except for one child’s Pb intake. Bio-accessibilities ranged between 0% to 93%, 0% to 103%, and 0% to 69%, for lead, cadmium, and arsenic, respectively. Although DI for TEs has been found lower than TL, these reference values have been recently decreased or withdrawn since it was for lead and arsenic whose TL were withdrawn by WHO.
ARTICLE | doi:10.20944/preprints202101.0541.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Bioremediation; gut microbiota; lactic acid bacteria, Enterobacterales; lead; cadmium; aluminum; Probiotics; ICP-MS
Online: 26 January 2021 (13:26:26 CET)
Hazardous toxic metals, such as lead and cadmium, and to a lesser extent aluminum, are extensively recognized as detrimental for health following ingestion within food and water, or following inhalation. Gut and food-derived microbes, by interacting with heavy metals, may actively or passively modulate their bioavailability inside the gut, either by adsorption or by sequestration. Such a bioremediation within the gut implies the selection of safe microbes, based on their specific capacities to immobilize metals. We investigated the metal removal ability of 225 bacteria toward the potential harmful trace elements lead, cadmium and aluminum in vitro, using Inductively Coupled Plasma Mass Spectrometry analysis. Interspecies and intraspecies comparisons were addressed and discussed among bacteria from the phylum Firmicutes, which are mostly lactic acid bacteria, including Lactobacillus spp, with some Lactococcus, Pediococcus and Carnobacterium representatives, Actinobacteria as well as Proteobacteria. The effect on mixture of lead and cadmium was also investigated. Although the purpose of such a screening is so far not to elucidate each of the various strain specific- and metal dependent- mechanisms of heavy metal removal, we identified potential bacteria which are able to alleviate Pb(II) and Cd(II) concerns in order to propose performing candidate probiotics for metal xenobiotic bioremediation.
ARTICLE | doi:10.20944/preprints201807.0520.v1
Subject: Life Sciences, Microbiology Keywords: c-di-GMP; Cupriavidus metallidurans; cadmium; phosphodiesterase; biofilm; urf2 gene; mer gene; PleD
Online: 26 July 2018 (15:51:36 CEST)
Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain for heavy metal resistance and bioremediation. The aim of this study was to determine the role of the c-di-GMP pathway in the C. metallidurans CH34 response to cadmium in both planktonic and biofilm cells. Increasing cadmium concentrations correlates with an inhibition of biofilm formation and EPS production in C. metallidurans cells. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium induced in planktonic cells and strongly induced in biofilm cells the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and null mutant complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated phosphodiesterase. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD* correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 involves a decrease in c-di-GMP content that inhibits the biofilm lifestyle.
ARTICLE | doi:10.20944/preprints201705.0120.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Aronia melanocarpa berries; bone biomechanical properties; cadmium; chokeberries; female rats; polyphenols; procollagen; protection
Online: 16 May 2017 (07:45:30 CEST)
The hypothesis that consumption of Aronia melanocarpa berries (chokeberries) extract, recently reported by us to improve bone metabolism in female rats at low-level and moderate chronic exposure to cadmium (1 and 5 mg Cd/kg diet for up to 24 months), may increase the bone resistance to fracture was investigated. Biomechanical properties of the neck (bending test with vertical head loading) and diaphysis (three-point bending test) of the femur of rats administered 0.1% aqueous chokeberry extract (65.74% of polyphenols) or/and Cd in the diet (1 and 5 mg Cd/kg) for 3, 10, 17, and 24 months were evaluated. Moreover, procollagen I was assayed in the bone tissue. The low-level and moderate exposure to Cd decreased procollagen I concentration in the bone tissue and weakened biomechanical properties of the femoral neck and diaphysis. Chokeberry extract administration under the exposure to Cd improved the bone collagen biosynthesis and femur biomechanical properties. The results allow for the conclusion that consumption of chokeberry products under exposure to Cd may improve the bone biomechanical properties and protect from fracture. This study provides support for Aronia melanocarpa berries being a promising natural agent for the skeleton protection under low-level and moderate chronic exposure to Cd.
ARTICLE | doi:10.20944/preprints201810.0396.v1
Subject: Physical Sciences, Atomic & Molecular Physics Keywords: laser induced plasma spectroscopic (LIPS); optical emission spectroscopic (OES); spectroscopy diagnostic; cadmium telluride (CdTe)
Online: 18 October 2018 (04:26:08 CEST)
In this work, the parameters of plasma (electron temperature (Te), electron density ne, plasma frequency (fp) , Debye length (λD) and Debye number (ND)) have been studied by using the spectrometer that collect the spectrum of Laser produce Cadmium telluride plasma at different energies. The results of electron temperature for CdTe range 0.93-1.18 eV also the electron density 5 × 1010 – 3.8 × 1011 cm-3 have been measured under vacuum reaching 2.5 × 10-2 mbar .Optical properties of CdTe were determined through the optical transmission method using ultraviolet visible spectrophotometer within the range 190 – 1100 nm.
ARTICLE | doi:10.20944/preprints202103.0462.v1
Subject: Biology, Anatomy & Morphology Keywords: Antioxidants; ascorbate; Brassica juncea; cadmium stress; Cd defense and tolerance; glutathione; Indian mustard; sulfur assimilation.
Online: 18 March 2021 (09:29:59 CET)
The effect of four soil-applied sulfur [S; 100 mg S kg-1 soil (100S) and 200 mg S kg-1 soil (200S)] in different sources (elemental S, ammonium sulfate, gypsum or magnesium sulfate) in protecting mustard (Brassica juncea L. Czern & Coss.) from cadmium effects was studied. Based on the observed reduction in growth and photosynthesis in plants subjected to 100 and 200 mg Cd kg-1 soil, B. juncea cv. Giriraj was selected as the most Cd-tolerant among five cultivars (namely, Giriraj, RH-0749, Pusa Agrani, RH-406, and Pusa Tarak). Sulfur applied to soil mitigated the negative impact of Cd on sulfur assimilation, cell viability and photosynthetic functions, with a lower lipid peroxidation, electrolyte leakage, and contents of reactive oxygen species (ROS: hydrogen peroxide, H2O2, and superoxide anion, O2•−). Generally, added S caused a higher activity of antioxidant enzymes (ascorbate peroxidase, catalase and superoxide dismutase), and contents of ascorbate (AsA) and reduced glutathione (GSH), and increases in the activities of their regenerating enzymes (dehydroascorbate reductase and GSH reductase), as well as rises in S assimilation, biosynthesis of non-protein thiols (NPTs) and phytochelatins (PCs). Compared to the other S-sources tested, elemental S more prominently protected B. juncea cv. Giriraj against Cd-impacts by minimizing Cd-accumulation and its root-to-shoot translocation; decreasing cellular ROS and membrane damage, and improving Cd-chelation (NPTs and PCs), so strengthening the defense machinery against Cd. The results suggest the use of elemental S for favoring the growth and development of cultivated plants also in Cd-contaminated agricultural soils.
ARTICLE | doi:10.20944/preprints202003.0153.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: unrecorded alcohol; home-produced fruit spirits; metals; lead; cadmium; ethanol; health risk; risk assessment; margin of exposure
Online: 10 March 2020 (02:44:16 CET)
Unrecorded alcohol comprises all types of alcohol that is not registered in the jurisdiction where it is consumed. In some countries in Central and Eastern parts of Europe as well as the Balkan, the major amount of unrecorded alcohol consumption may derive from homeproduction of fruit spirits. Some studies found a high prevalence of lead and cadmium in such spirits. This article provides a quantitative comparative risk assessment using the margin of exposure (MOE) methodology for lead and cadmium, compared to ethanol, for unrecorded fruit spirits. For average concentration levels, the lowest MOE (0.8) was calculated for ethanol (alcohol itself). For lead, the MOE was 13 for moderate daily drinking and 0.9 for the worst case. For cadmium, the MOE was 1982 for moderate daily drinking and 113 for the worst case. The results of this study are consistent with previous comparative risk assessments that ethanol itself comprises by far the highest risk of all compounds in alcoholic beverages. Regarding the metal contaminants, the risk of cadmium appears negligible, however, lead may pose an additional health risk in heavy drinking circumstances. Strategies to avoid metal contamination in settings of artisanal homeproduction of spirits need to be developed.