Influence of Chromium Stress on Chlorophyll Content, Polyphenol Oxidase and Peroxidase Activity in Horse Gram (Dolichos biflorus L)

The presence of heavy metals in solid and liquid wastes is a significant issue in terms of the environment degradation. These are one of the most serious environmental pollutants, and reaching dangerous levels will need more investigation. Chromium, in particular, has become a global environmental problem among heavy metals. This research looked at the effects of Cr207 stress on Dolichos biflorus L., a kind of horse grain that plays an essential role in Indian agriculture. D. biflorus seeds were cultivated in the dark under laboratory conditions with a Sodium chromate concentration of (0-3.0mg/L). The control treatment was distilled water. Seven-day-old seedlings were utilized to study the effects of chromate stress on peroxidase activity and chlorophyll content. The findings showed that when the quantity of Sodium chromate increased, the chlorophyll content of D. biflorus seedlings increased considerably (p 0.9). Increased polyphenyloxiase and peroxidase activity indicated the appearance of a scavenging mechanism in plants under heavy metal stress, whereas increased peroxidase quantity indicated the generation of free radicals. The drop in chlorophyll concentration indicates that the plants' development has slowed, resulting in a fall in production.

A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance

BACKGROUND: Acidophilic microorganisms like Leptospirillum sp. CF 1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF 1 are known to be up regulated under oxidative stress conditions. RESULTS: In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF 1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co transcriptional study using RT PCR showed that ABH19_09590 is contained in an operon, here named the "och" operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up regulated in Leptospirillum sp. CF 1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di hydroxy acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. CONCLUSIONS: Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.

Loofah immobilized with Cladosporium cladosporioides CEL14 is a potential bioremediating agent for hexavalent chromium in tannery wastewater

Aims@#Chromium salt possesses unique characteristics that render it useful in numerous applications in several industrial processes, especially tanning of animal hides which act as a major source of hexavalent chromium toxicity in environment. This study aimed to evaluate the efficiency of loofah immobilized Cladosporium cladosporioides CEL14 in remediate tannery wastewater which contains hexavalent chromium. @*Methodology and results@#A total of 18 fungal species were isolated from three different sites of tannery wastewater in Egypt, of which C. cladosporioides CEL14 was the most capable species of chromate remediation with 81% after 7 days of incubation as free cells. The experiments were conducted in minimum salt medium supplemented with 200 ppm chromate in the form of potassium dichromate. Different process parameters studies demonstrated that chromate was completely removed at 30 °C, pH 6, 0.1% malt extract and 0.2% glucose after 7 days of incubation with 20% inoculum size. After that, C. cladosporioides was immobilized on a natural support material (loofah). The removal ability of chromate was enhanced through permanent viable immobilization on loofah pieces, which showing complete removal of chromate within 3 days. The toxicity assessment of treated tannery effluents revealed that 74% of Brassica napus seeds were germinated upon exposure to the treated effluent.@*Conclusion, significance and impact of study@#This study revealed that C. cladosporioides CEL14 isolate has high potential as bioremediating agent against toxic hexavalent chromium. The removal ability of toxic chromate was enhanced through permanent viable immobilization on loofah pieces. This technology is simple, cost effective, efficient and environmentally friendly. The loofah immobilized with C. cladosporioides CEL14 has potential to be applied in wastewater treatment of small-scale tanneries after onsite trials.

Effect of hOGG1 gene polymorphisms on urinary 8-OHdG level in occupational chromate exposed population / 中国职业医学

OBJECTIVE: To evaluate the genetic damage induced by occupational chromate exposure, and to analyze the association between human 8-oxoguanine-DNA N-glycosylase 1(hOGG1) polymorphisms and genetic damage in population with chromate exposure. METHODS: A total of 136 chromate exposed workers were recruited as exposure group by judgmental sampling method, and 156 workers without chromate and other occupational hazard factors exposure were recruited as control group. The whole blood chromium(WB-Cr) level was measured by inductively coupled plasma mass spectrometry. Urinary 8-hydroxy-2′-deoxyguanosine(8-OHdG) was determined by enzyme-linked immunosorbent assay. Four single nucleotide polymorphisms of hOGG1 gene were genotyped by the matrix assisted laser desorption ionization/time of flight mass spectrometry. RESULTS: The WB-Cr level was higher in the exposure group than that in the control group(meclian: 3.41 vs 0.90 μg/L, P<0.01). The urinary 8-OHdG level was higher in the exposure group compared with that in the control group(meclian: 6.02 vs 4.72 μg/g·creatinine, P<0.01). In study subjects(exposure group and control group), after adjusting the potential influencing factors such as age, body mass index(BMI), gender, smoking and drinking, chromate exposure might be a risk factor for increasing urinary 8-OHdG level(P<0.05), and the recessive models of rs293796 and rs13096551 were observed as risk factors of increasing urinary 8-OHdG level(P<0.05). In chromate exposure group, the additive and recessive models of rs293796 and the recessive model of rs13096551 were observed as risk factors of increasing urinary 8-OHdG level(P<0.05), while the dominant model of rs3219008 was protective factor of increasing urinary 8-OHdG level(P<0.05), after adjusting the potential influencing factors such as age, BMI, gender, smoking, drinking. However, after multiple Bonferroni correction tests, only the recessive model of rs293796 was the risk factor of increasing urinary 8-OHdG level in the exposed group(P<0.01). There was significant interaction between chromate exposure and rs293796 on urinary 8-OHdG(P<0.01). CONCLUSION: The rs13096551 and rs293796 of hOGG1 were associated with the alteration of urinary 8-OHdG level induced by chromate. There was interaction between rs294796 of hOGG1 and chromate exposure on urinary 8-OHdG level.

Clinical Characteristics of Patients with Chromium Allergy in a Single University Hospital in Korea / 대한피부과학회지

BACKGROUND: Chromium is one of the most common metal allergens that cause allergic contact dermatitis. European regulation of chromium (VI) content in cement was first implemented in 2005, and regulation of chromium in leather in 2015. OBJECTIVE: This clinical study was performed to obtain basic data on subjects with allergic contact dermatitis due to chromium in Korea. We investigated the clinical characteristics of patients with chromium allergy among subjects with contact dermatitis who underwent patch tests. METHODS: Patch test data from June 1998 to January 2014 were retrospectively analyzed (n=975; men=290, women=685). Patients who showed positive reactions to potassium dichromate (chromium [+] group; n=58) and who showed positive reactions to other allergens except potassium dichromate (others [+] group; n=497) were identified and the characteristics of both groups were compared. Patients who only reacted to chromium (only chromium group; n=17) were identified, and their clinical characteristics were investigated. The prevalence of chromium allergy was analyzed in each 4-year period to study the changes over time. RESULTS: The sensitization rate of potassium dichromate was 5.9% (n=58) and women comprised 72.4% (n=42) of the chromium (+) group. Hands and feet were more frequently affected in the chromium (+) group (p=0.002 and 0.019, respectively). Occupational dermatitis was significantly less common in the chromium (+) group. Chromium allergy was the most prevalent in patients in their 50s (8.4%). The only chromium group had significantly more number of patients aged 40 years or older (p=0.004). The prevalence of chromium allergy was 13.5% during 1998~2002, but decreased to 5.4% during 2010~2014. CONCLUSION: The characteristics of patients with chromium allergy suggests that chromium exposure in daily activities, including leather exposure, is more relevant than occupational exposure for most patients. The prevalence of chromium allergy has been decreasing in Korea, which may be an effect of voluntary regulation of chromium content in cement by manufacturers.

Cytogenomics of hexavalent chromium (Cr6+) exposed cells: A comprehensive review.

The altered cellular gene expression profile is being hypothesized as the possible molecular basis navigating the onset or progress of various morbidities. This hypothesis has been evaluated here in respect of Cr6+ induced toxicity. Several studies using gene microarray show selective and strategic dysregulations of cellular genes and pathways induced by Cr6+. Relevant literature has been reviewed to unravel these changes in different test systems after exposure to Cr6+ and also to elucidate association if any, of the altered cytogenomics with Cr6+ induced toxicity or carcinogenicity. The aim was to verify the hypothesis for critical role of altered cytogenomics in onset of Cr6+ induced biological / clinical effects by identifying genes modulated commonly by the toxicant irrespective of test system or test concentrations / doses, and by scrutinizing their importance in regulation of the flow of mechanistically linked events crucial for resultant morbidities. Their probability as biomarkers to monitor the toxicant induced biological changes is speculative. The modulated genes have been found to cluster under the pathways that manage onset of oxidative stress, DNA damage, apoptosis, cell-cycle regulation, cytoskeleton, morphological changes, energy metabolism, biosynthesis, oncogenes, bioenergetics, and immune system critical for toxicity. In these studies, the identity of genes has been found to differ remarkably; albeit the trend of pathways’ dysregulation has been found to remain similar. We conclude that the intensity of dysregulation of genes or pathways involved in mechanistic events forms a sub-threshold or threshold level depending upon the dose and type (including speciation) of the toxicant, duration of exposure, type of target cells, and niche microenvironment of cells, and the intensity of sub-threshold or threshold level of the altered cytogenomics paves way in toxicant exposed cells eventually either to opt for reversal to differentiation and growth, or to result in toxicity like dedifferentiation and apoptosis, respectively.

Acute toxicity of potassium bichromate and 3,4-dichloroaniline in Chinese rare minnow (Gobiocypris rarus) / 中国实验动物学报

Objective and Methods As a local species, Chinese rare minnow (Gobiocypris rarus) has been one of the standardized test fish for chemical toxicity tests in China .By optimal screening , the acute toxicity of potassium bichromate and 3,4-dichloroaniline (3,4-DCA) was determined to evaluate repeatability and accuracy for Gobiocypris rarus in one laboratory and between different laboratories .Result Based on a proper data analysis , for the two chemicals per-formed with the same fish, all 96 h LC50 values were within mean ( x-) and upper and lower control limits ( ±2s) in both inner test ( in one laboratory ) and outer test ( between different laboratories ) .Conclusions From these results , a valid database could also be established to evaluate one single test .In addition, Gobiocypris rarus will not only be a potential test species for ecotoxicity tests , but also recommended as a standard laboratory animal .

Evaluation of in vitro Reduction of Hexavalent Chromium by Cell-Free Extract of Arthrobacter sp. SUK 1201.

Aims: This study aims at to evaluate the hexavalent chromium [Cr(VI)] reduction potential of crude cell-free extracts of chromium resistant and reducing bacterium Arthrobacter sp. SUK 1201 and determination of optimum conditions for Cr(VI) reduction for possible bioremediation of Cr pollutants. Place and Duration of Study: Chromium reduction studies with Arthrobacter sp. SUK 1201, was undertaken in the Microbiology Laboratory, Department of Botany, University of Calcutta, Kolkata during 2010-2012. Methodology: Cell-free extract was prepared from freshly grown cell mass of Arthrobacter sp. SUK 1201 following the standard procedure. Cell mass suspended in Tris-HCl was sonicated (120 KHz for 30 min), centrifuged (12,000×g at 4ºC for 10 min) and the supernatant (S12) was used as the cell- free extract (CFE). Chromate reductase activity of the CFE was assayed colorimetrically using 1, 5-diphenylcarbazide as the complexing reagent. Results: Chromate reductase activity of CFE of Arthrobacter sp. SUK 1201 was constitutive in nature and reduced Cr(VI) with decreasing efficiency as the concentration of Cr(VI) was increased. Its Km and Vmax were 263.45 M Cr(VI) and 17.5 U mg-1 protein respectively. Reduction of Cr(VI) was optimal at pH 7 and 32ºC but was extremely thermolabile. NADH was the most suitable electron donor, and the chromate reduction was enhanced by Cu(II) and Fe(III), but inhibited by Hg(II). Among the different inhibitors tested, 2, 4-dinitrophenol (DNP) restored nearly 96.4% reductase activity, while carbonyl cyanidem- chloro phenyl hydrazone (CCCP) was most inhibitory to the process. Conclusion: It has been established that the Cr(VI) reduction potential of the cell-free extract of Arthrobacter sp. SUK 1201 is promising and could be exploited in the bioremediation of toxic hexavalent chromium.

Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6-17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate

Isolation and characterization of novel potent Cr(VI) reducing alkaliphilic amphibacillus sp. ksuCr3 from hypersaline soda lakes

A strain KSUCr3 with extremely high Cr(VI)-reducing ability under alkaline conditions was isolated from hypersaline soda lakes and identified as Amphibacillus sp. on the basis of 16S rRNA gene sequence analysis. The results showed that Amphibacillus sp. strain KSUCr3 was tolerance to very high Cr(VI) concentration (75 mM) in addition to high tolerance to other heavy metals including Ni2+ (100 mM), Mo2+ (75 mM), Co2+ (5 mM), Mn2+ (100 mM), Zn2+ (2 mM), Cu2+ (2 mM) and Pb (75 mM). Strain KSUCr3 was shown to be of a high efficiency in detoxifying chromate, as it could rapidly reduce 5 mM of Cr(VI) to a non detectable level over 24 hrs. In addition, strain KSUCr3 could reduce Cr(VI) efficiently over a wide range of initial Cr(VI) concentrations (1-10 mM) in alkaline medium under aerobic conditions without significant effect on the bacterial growth. Addition of glucose, NaCl and Na2CO3 to the culture medium caused a dramatic increase in Cr(VI)-reduction by Amphibacillus sp. strain KSUCr3. The maximum chromate removal was exhibited in alkaline medium containing 1.5 percent Na2CO3, 0.8 percent glucose, and 1.2 percent NaCl, at incubation temperature of 40ºC and shaking of 100 rpm. Under optimum Cr(VI) reduction conditions, Cr(VI) reduction rate reached 237 uMh¹ which is one of the highest Cr(VI) reduction rate, under alkaline conditions and high salt concentration, compared to other microorganisms that has been reported so far. Furthermore, the presence of other metals, such as Ni2+, Co2+, Cu2+ and Mn2+ slightly stimulated Cr(VI)-reduction ability by the strain KSUCr3.The isolate, Amphibacillus sp. strain KSUCr3, exhibited an ability to repeatedly reduce hexavalent chromium without any amendment of nutrients, suggesting its potential application in continuous bioremediation of Cr(VI). The results also revealed the possible isolation of potent heavy metals resistant bacteria from extreme environment such as hypersaline soda lakes.

Identification of bacterial strains from tannery effluent and reduction of hexavalent chromium.

Four chromium-resistant bacteria were isolated from tannery effluent collected from Burgelarab, Alexandria, Egypt. These isolates displayed different degrees of chromate reduction under aerobic conditions. Based on 16S rDNA gene sequence analysis, two of them (S3 and S4) were identified as Acinetobacter, and Pseudomonas, respectively. The minimum inhibitory concentration for Acinetobacter sp. strain S3 was 160 mg l-1, while it was 200 mg l-1 for Pseudomonas sp. strain S4. However, strain S4 was able to reduce a wide range of Cr (VI) concentrations from 20 to 200 mg l-1; while, it was reducing 64.4% of Cr (VI) at 160 mg l-1 within 72 hr. Immobilization experiments demonstrated that strain S4 in calcium alginate gel matrix was more effective than the using of free cells in chromium reduction.

Determination of Sulfate in Water by Barium Chromate Spectrophotometry / 环境与健康杂志

Objective To establish a rapid determination method for sulfate in water. Methods In the weak acid solution, sulfate connected with barium chromate into sulfate barium and chromate. Surplus barium chromate precipitated when adding the mixture of CaCl2 and NH3?H2O. The chromate replaced by sulfate was detected at wave length of 420 nm. Results The RSDs were 1.8%-6.8% and the recovery rates were 98.9%-101.0%. Conclusion The method was rapid, simple and its sensitivity and accuracy can meet the requirement of standard examination methods for drinking water.

Content Determination of Domiphen by Potassium Chromate Indicator Method / 中国药房

OBJECTIVE: To establish a method for the content determination of domiphen by potassium chromate indicator method.METHODS: The contents of domiphen were determined based on the theory that bromide ion in domiphon could react with AgNO3 to produce silver bromide precipitation.The method was compared with the sodium tetraphenylborate method issued in China Pharmacopeica(2005 edition).RESULTS: The RSD of contents was 0.18%,and the average recovery was 100.2% in the potassium chromate indicator method.There was no significant difference between the results of two determination methods by t-test.CONCLUSION: The potassium chromate indicator method is simple,fast and accurate,which can be used for the content determination of domiphen.

The effects of chromium exposure on sister chromatid exchange and concentration of 8-hydroxydeoxyguanosine / 예방의학회지

To elucidate some DNA adducts as a biological marker for workers of chromate pigment, the effects of chromium exposure on the formation of 8-hydroxydeoxyguanosine(8-OH-dG) and sister chromatid exchanges(SCEs) frequency in 38 workers of a pigment plant in Bucheon which utilized lead chromates, were examined. The chromium contents of venous blood and urine were measured as working environmental exposure level. The concentrations of 8-OH-dG in DNA isolated from lymphocytes were determined with high performance liquid chromatography and electrochemical detector and denoted as a molar ratio of 8-OH-dG to deoxyguanosine(dG). The SCEs frequency were analyzed in DNA isolated from lymphocytes. A significant correlation was found between creatinine adjusted urine chromium concentration and the molar ratio of 8-OH-dG to dG(r=0.47, p<0.01). After adjusting the current smoking habit, the correlation coefficient was increased(r=0.62, p<0.05). However, there was no significant correlation between the SCE frequency and chromium exposure. This significant results between molar ratio of 8-OH-dG to dG and chromium exposure are in good agreement with in vitro studies that support the importance of DNA adduct formation for the carcinogenic effect of chromium.