Bleeding Post Constriction Ring Release Surgery Causing Lower Limb Ischemia in an Infant with Undetected Hemophilia B.

Bleeding in the immediate postoperative period causing compromised limb circulation is an alarming complication. It is known to occur in coagulation disorders like hemophilia. When such complications happen in a child with no previous history of bleeding problems, one has to have a low threshold for suspecting a coagulation disorder. Repeated diffuse bleeding in the whole of the surgical wound with no specific bleeders must raise the suspicion and appropriate laboratory tests must immediately be ordered. Bleeding in coagulation disorders can stop only with supplementation of the appropriate missing clotting factor. Early diagnosis is important to avoid excess morbidity. We are reporting a 6-month-old child who underwent surgery for constriction ring syndrome in the limbs with Z-plasty please replace with and developed impending limb ischemia due to bleeding in the immediate postoperative period. The article emphasizes the need to think of the possibility while encountering recurrent bleeding in the postoperative period.

"On Arrival Block"-Management of Upper Extremity Trauma with Resuscitation in the Operating Room.

"On Arrival Block," wherein a brachial block is given to a severely injured upper extremity as the first step of the management protocol in the main operating room, bypassing the emergency department, has been found to be a "game changer" in trauma care. Immediate pain relief on arrival builds confidence in the system, allows pain-free initial examination, facilitates use of tourniquet if there are major bleeding wounds, and allows us to obtain good radiographs without an overlap of bones, which usually happens when the radiographs are taken within a bandage. Using the "On Arrival Block" system, emergency room assessment and resuscitation is bypassed. The patient is resuscitated only once, instead of twice. This avoids much duplication of effort, wasted time, patient suffering, unnecessary costs, and mistakes generated by miscommunication between 2 resuscitation teams. This can be done only in the place where all the resuscitative equipment and drugs are available. A senior anesthesiologist and surgeon must be available. The only contraindication is the suspicion of a brachial plexus injury, which can cause the local anesthetic to seep in through the open dural sleeve and cause total spinal anesthesia. "On Arrival Block" was set up at Ganga Hospital, Coimbatore, India, during the early 90s by the anesthesiologist Ravindra Bhat and the plastic surgeon Raja Sabapathy out of necessity, who recognized its value and made it the standard of care.

In vivo AFB1 detoxification by Lactobacillus fermentum LC5/a with chlorophyll and immunopotentiating activity in albino mice.

The potential Aflatoxin B1 (AFB1) binding Lactobacillus fermentum (LC5/a) was used for in vivo AFB1 binding and detoxification in presence of chlorophyll (CL) in male Swiss albino mice. Mice were randomly divided into seven groups. The control groups (CL, AFB1 and LC5/a) received chlorophyll (250 µg/kg b.w), AFB1 (100 µg/kg b.w) and LC5/a (1 × 108 CFU) for 21 days. The treatment group (AFB1+LC5/a) received 100 µl of lyophilized bacterial suspension (1 × 108 CFU) 2 h before the AFB1 dosage (100µg/kg b.w). The chlorophyll mice group (CL + AFB1) was given single oral dose of CL (250 µg/kg b.w) before AFB1 dosage and last mice group received the combination of CL + LC5/a before the AFB1 dosage over a period of 21 days. Ballooning of cytoplasm and necrosis in liver was evident in histopathological examination of AFB1 mice group, while, marked improvement and nearly normal histology were seen in LC5/a and CL treated mice group. The levels of AST, ALT, GST, and SOD were increased in AFB1 mice group compared to LC5/a and CL treated mice group. Elevated levels of pro-inflammatory cytokines, TNF-α, IL-12, IL-6 (324, 506, 117.25 pg/ml) were observed in AFB1 treated mice serum compared to LC5/a and CL treated mice (249.54, 322.01 and 82.35 pg/ml). Thus, Lactobacillus fermentum LC5/a has certainly sequestered AFB1 from gastrointestinal tract besides regulating the production of pro-inflammatory cytokines.

Mechanism of inhibition of aflatoxin synthesis by non-aflatoxigenic strains of Aspergillus flavus.

Aflatoxins are toxic secondary metabolites primarily produced by Aspergillus flavus and A. paraciticus. Exposure to these mycotoxins through contaminated food and feed may cause oxidative stress and liver toxicity in animals. One of the promising strategies to mitigate aflatoxin accumulation is the biological management during pre-harvest using non-aflatoxigenic A. flavus. The mechanism offered by these strains in mitigating aflatoxin is still unclear. Thus, the aim of the present study is to delineate the mechanism of intraspecific inhibition of aflatoxin production. Among the 18 non-aflatoxigenic strains evaluated, six strains were able to reduce more than 50% of the aflatoxins produced by the native aflatoxigenic strains. The non-aflatoxigenic strains used in this study failed to degrade the aflatoxins. Eventhough, the non-aflatoxigenic strains were not able to inhibit the synthesis of aflatoxins completely. Four non-aflatoxigenic isolates could competitively excluded the aflatoxigenic strain. Furthermore, when non-aflatoxigenic and an aflatoxigenic isolate were separated by 0.4 and 3 µm filters, aflatoxin synthesis was not significantly reduced. However, when the pore size was 8 µm, there was a significant decrease in aflatoxin production. This results suggest the role of physical contact between the hyphae, thigmoregulation, in the inhibition of aflatoxin production. Additionally, to better understand the transcriptional level control of this phenomenon, we analyzed the gene expression profile of aflatoxin biosynthesis genes in the aflatoxigenic strain. The aflatoxin biosynthesis genes were down regulated in the aflatoxigenic strain in contact with non-aflatoxigenic strain group when compared to the control. This is the first evidence of the combined action of competitive exclusion and thigmodownregulation which led to the intraspecific inhibition of aflatoxin production.

Molecular profile of non-aflatoxigenic phenotype in native strains of Aspergillus flavus.

Aflatoxins are the most common mycotoxin contaminant reported in food and feed. Aflatoxin B1, the most toxic among different aflatoxins, is known to cause hepatocellular carcinoma in animals. Aspergillus flavus and A. parasiticus are the main producers of aflatoxins and are widely distributed in tropical countries. Even though several robust strategies have been in use to control aflatoxin contamination, the control at the pre-harvest level is primitive and incompetent. Therefore, the aim of the study was to isolate and identify the non-aflatoxigenic A. flavus and to delineate the molecular mechanism for the loss of aflatoxin production by the non-aflatoxigenic isolates. Eighteen non-aflatoxigenic strains were isolated from various biological sources using cultural and analytical methods. Among the 18 isolates, 8 isolates produced sclerotia and 17 isolates had type I deletion in norB-cypA region. The isolates were confirmed as A. flavus using gene-specific PCR and sequencing of the ITS region. Later, aflatoxin gene-specific PCR revealed that the defect in one or more genes has led to non-aflatoxigenic phenotype. The strain R9 had maximum defect, and genes avnA and verB had the highest frequency of defect among the non-aflatoxigenic strains. Further, qRT-PCR confirmed that the non-aflatoxigenic strains had high frequency of defect or downregulation in the late pathway genes compared to early pathway genes. Thus, these non-aflatoxigenic strains can be the potential candidates for an effective and proficient strategy for the control of pre-harvest aflatoxin contamination.

Characterization of Novel Lactobacillus fermentum from Curd Samples of Indigenous Cows from Malnad Region, Karnataka, for their Aflatoxin B1 Binding and Probiotic Properties.

Thirty-four isolates of Lactobacillus spp. (LAB) from 34 curd samples were evaluated for their aflatoxin B1 (AFB1) binding and probiotic properties. Upon characterization, four LAB isolates (LC3/a, LC4/c, LC/5a, and LM13/b) were found to be effective in removing AFB1 from culture media with a capacity of above 75%. Staining reaction, biochemical tests, pattern of sugar utilization, and 16s rRNA gene sequence analysis revealed the identity of all the four isolates as L. fermentum. All of them could tolerate acidic pH, salt, and bile, which promise the use of these probiotic bacterial isolates for human applications. These isolates showed poor hydrophobicity and higher auto-aggregation properties. All L. fermentum isolates were found susceptible to gentamycin, chloramphenicol, cefoperazone, ampicillin, and resistant to ciprofloxacin and vancomycin. Results of hemolytic and DNase activity indicated their nonpathogenic nature. Though all L. fermentum isolates found inhibiting the growth of Salmonella ebony, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, maximum inhibition was obtained with isolate LC5/a. Kinetic studies revealed that all four bacteria required a minimum of 2 h to reach stationary phase of AFB1 binding. AFB1 binding ability varied from 66 to 85.2% among these four isolates. Bile (0.4%) was significant (P ≤ 0.05) in reducing the AFB1 binding property of isolates LC3/a, LC4/c, and LM13/b, while increased AFB1 binding ability was recorded at acidic pH (2.0). AFB1 binding properties of isolate LC5/a were found least affected by acidic pH and bile. The findings of our study revealed the higher efficiency of L. fermentum isolate LC5/a in reducing the bioavailability of AFB1 in gut, and additionally, it improves the consumers' health by its various probiotic characters. These beneficial characters, L. fermentum isolates, promise them to use as probiotic formulations alone or in combinations with other beneficial probiotic-bacterial isolates.

Use of Lactobacilli in Cereal-Legume Fermentation and as Potential Probiotics towards Phytate Hydrolysis.

Phytate is a potent inhibitor of mineral absorption in humans occurring in plant-based food. Application of lactobacilli that produce phytate-degrading enzymes (phytases) to reduce phytate is an interesting yet a not much explored sector of research. Therefore, phytate dephosphorylation by Lactobacillus plantarum MTCC 1325 was evaluated. Cells at stationary phase showed phytase activity which was maximal at 24 h of growth. Glucose concentration and the type of phosphorous source in the media modulated the enzyme activity. Fermentation of cereal and/or legume flours with the strain resulted in phytate reduction with the highest in sorghum (73%) and the lowest in horse gram (34%). Further, the strain showed tolerance to acid, bile, and simulated gastrointestinal fluid. Significant phytase activity in the presence of simulated gastrointestinal fluids along with the ability to produce phytases post-exposure to simulated gastrointestinal fluids is of interest. To the best of our knowledge, this is the first report on the effect of simulated gastrointestinal fluid on cell-associated phytases of lactobacilli. The results of the investigation indicate that L. plantarum MTCC 1325 could be used as a starter in cereal-legume fermentation and as potential probiotics to achieve phytate hydrolysis in food matrices and also in gastrointestinal tract.

The interactome of metabolic enzyme carbonic anhydrase IX reveals novel roles in tumor cell migration and invadopodia/MMP14-mediated invasion.

Carbonic anhydrase IX (CAIX) is a hypoxia inducible factor 1-induced, cell surface pH regulating enzyme with an established role in tumor progression and clinical outcome. However, the molecular basis of CAIX-mediated tumor progression remains unclear. Here, we have utilized proximity dependent biotinylation (BioID) to map the CAIX 'interactome' in breast cancer cells in order to identify physiologically relevant CAIX-associating proteins with potential roles in tumor progression. High confidence proteins identified include metabolic transporters, ß1 integrins, integrin-associated protein CD98hc and matrix metalloprotease 14 (MMP14). Biochemical studies validate the association of CAIX with α2ß1 integrin, CD98hc and MMP14, and immunofluorescence microscopy demonstrates colocalization of CAIX with α2ß1 integrin and MMP14 in F-actin/cofilin-positive lamellipodia/pseudopodia, and with MMP14 to cortactin/Tks5-positive invadopodia. Modulation of CAIX expression and activity results in significant changes in cell migration, collagen degradation and invasion. Mechanistically, we demonstrate that CAIX associates with MMP14 through potential phosphorylation residues within its intracellular domain, and that CAIX enhances MMP14-mediated collagen degradation by directly contributing hydrogen ions required for MMP14 catalytic activity. These findings establish hypoxia-induced CAIX as a novel metabolic component of cellular migration and invasion structures, and provide new mechanistic insights into its role in tumor cell biology.

Protective effect of bacillopeptidase CFR5 from Bacillus subtilis CFR5 on cerulein-induced pancreatitis.

Bacillopeptidase is a serine peptidase, known for its fibrinolytic activity. However, a very little information is known about its in vivo inflammatory and/or anti-inflammatory properties. Thus, to understand whether bacillopeptidase incorporation can regulate pancreatitis or not, the cerulein-induced pancreatitis model was used, and the role of bacillopeptidase on pancreatitis was studied. In this study, 46 kDa protein was purified from Bacillus subtilis and identified as bacillopeptidase CFR5 (BPC) through MS/MS analysis. The nutritional prophylactic group was orally fed with two doses of BPC (100 µg/Kg/BW of rat) 6 h before cerulein administration and analyzed for its effect on intestine and pancreas inflammation, cytokines, and pancreatitis marker gene expression. BPC administration significantly reduced the severity of pancreatitis by decreasing serum amylase, lipase, pancreatic edema and myeloperoxidase activity. The pretreatment with BPC suppressed the pancreatic pro-inflammatory and inflammatory cytokines production including IL-6, IL-1ß, TNF-α, IL-2, IL-4, IL-5, IL-10, and IL-13 in both pancreas and serum samples. Moreover, BPC supplementation restored pancreatitis mediated disruption of intestinal barrier integrity by upregulating tight junction proteins (ZO-1, occludin), antimicrobial peptides (DEFB1, CRAMP), MUC-2, TFF3 expression and by enhancing SCFA's production. Pretreatment with BPC suppressed the intestinal inflammation with reduced cytokines production in the colon and ileal region of cerulein-induced pancreatitis. Thus, BPC based pretreatment protocol is a novel intervention to prevent acute pancreatitis.

Extracellular phytase from Aspergillus niger CFR 335: purification and characterization.

Phytase, that is extensively used as a feed additive is capable of hydrolyzing phytic acid, an antinutrient found in about 60-80 % of all the plant commodities. This enzyme improves the bioavailability of essential minerals such as Ca(2+), Mg(2+), P, Zn(2+), Fe(3+), that are bound to phytic acid. An extracellular phytase from a local fungal isolate, Aspergillus niger CFR 335 was purified to homogeneity through a three-step column chromatography using DEAE-Sephadex anion exchanger. An active fraction of the enzyme was obtained with NaCl gradient of 2.5 M in DEAE Sephadex column. The enzyme was purified up to 16 fold with a yield of 28.5 %. Substrate specificity studies revealed a highest specific activity of 32.6 ± 3.1 U/mg for sodium phytate with the Km value of 0.08 ± 0.1 mM. The molecular weight of the enzyme was 66 kDa with an optimum temperature of 30 °C and pH 4.5. Up to 80 % of the activity was retained even after storing the enzyme for 6 months at 4 °C.

Transport via xylem and accumulation of aflatoxin in seeds of groundnut plant.

Aflatoxin contamination in groundnut seeds in the absence of any aflatoxigenic fungi leads to a hypothesis that aflatoxins are present naturally in soil and is transferred to seeds through uptake by roots. A survey was conducted on the natural occurrence of aflatoxins in agricultural soils, among nine main groundnut-growing regions of Karnataka state, India. All 71 soil samples collected in this survey were contaminated with aflatoxins esp. AFB1. An in vitro xylem sap experiment proved the ability of groundnut plant roots to absorb AFB1, and transport to aerial plant parts via the xylem. Hydroponics experiment also proved the uptake of AFB1 by the roots and their translocation to shoot. Uptake was affected by the initial concentration of toxin and pH of the medium. Among the 14 varieties screened, GPBD4 and MLT.K.107 (III) recorded highest and least AFB1 uptake, respectively. The above results were validated using a greenhouse experiment. Here, the aflatoxin absorbed by root gradually transferred to shoot that was later found in seeds towards the end of experiment. Thus, the groundnut seeds can also get contaminated with aflatoxin by direct uptake of aflatoxin through conducting tissue in addition to fungal infection. The present study revealed the novel mode of aflatoxin contamination in groundnut seeds without fungal infection.

Natural aflatoxin uptake by sugarcane (Saccharum officinaurum L.) and its persistence in jaggery.

The present study focused on aflatoxin (AF) uptake by sugarcanes from contaminated soils, and its persistence in jaggery. Analysis of 25 agricultural soil samples from sugarcane growing fields revealed that 80% were found contaminated with AF ranging from 0.5 to 22 ppb and all samples harbored aflatoxigenic fungi. Forty percent of the juices extracted from sugarcane grown in contaminated soil recorded AF ranging from 1.0 to 9.5 ppb. Conversely, jaggery prepared from those samples was almost free from AF. Further, greenhouse experiment confirms the AF uptake ability of sugarcane plants. Analysis of sugarcane juice and jaggery collected from local vendor showed 21% (0.5 to 6.5 ppb) and 5.6% (0.5-1.0 ppb) of AF contamination, respectively. Aflatoxigenic Aspergillus flavus strain was evaluated for their ability to grow and produce AF on jaggery medium. At 14th day after inoculation, decreased concentration of AF was recorded in jaggery medium ranging from 0 to 120 mg jaggery/ml, above which AF was absent though the fungal growth was noted. From the results, it could be concluded that sugarcane plants have the ability to uptake AF from contaminated soil, but AF was reduced during jaggery preparation. Also, higher concentration of jaggery was inhibitory to AF production.

Mechanism of aflatoxin uptake in roots of intact groundnut (Arachis hypogaea L.) seedlings.

Aflatoxins are one of the most potent toxic substances that occur naturally, which enter agricultural soils through the growth of aflatoxigenic fungi in rhizhosphere and nonrhizhosphere soils. Though several reports regarding the uptake of aflatoxin by plants are available, the mechanism of aflatoxin uptake remains unknown. This study characterized the aflatoxin uptake mechanism by in vitro hydroponic experiments under variable conditions. The uptake reached saturation after 48 h of incubation for AFB1 and B2 and 60 h for AFG1 and G2. A linear increase in uptake with increasing aflatoxin concentrations was observed, and it fits both linear and nonlinear regression. AFB1 uptake was directly proportional to transpiration rate, and blocking aquaporin activity using mercuric chloride revealed its involvement in the uptake. None of the metabolic inhibitors used to block active transport had any effect on aflatoxin uptake except for sodium azide. From the present study, it could be concluded that aflatoxin uptake by groundnut roots followed mainly a passive way and is facilitated through aquaporins. The involvement of active component should be studied in detail.

Natural occurrence of aflatoxin in green leafy vegetables.

Natural occurrence of aflatoxin (AF) in agricultural soils, green leafy vegetables (GLVs) and persistence in processed foods was investigated. in total 33 soil samples and 81 GLVs which belonged to 9 groups collected from nine vegetable-growing regions were studied. Seventy percent of soils and 69.2% GLVs were contaminated with AF ranging from 0.0 to 88 ppb. Root samples frequently had higher concentration of AFB(1) in comparison with shoot samples. Under greenhouse conditions all the tested plants were found to take up AF. From xylem and phloem sap experiments it was clear that AF was gaining entry into the plant system via water-conducting xylem tissue and was translocated to aerial plant parts, with subsequent entry into the phloem. Of the two cooking methods studied, pressure cooking of GLVs significantly reduced the AF level in comparison with ordinary boiling.

Safety evaluation of Mucor rouxii CFR-G15 biomass containing ω-6 fatty acids in rats.

Mucor rouxii CFR-G15 is an oleaginous zygomycetous fungus. The mycelia of the fungus accumulate 35.0±0.8% total lipid of which, 18.55±0.46% is gamma linolenic acid. Acute and subchronic studies were conducted by feeding rats with dry biomass of M. rouxii CFR-G15 to assess the safety of the oils in the fungal mycelium. For acute toxicity studies, adult male rats fed with diet at 0, 5000, 10,000, 25,000, 50,000 mg/kg bw for 1 day, and the animals were monitored for 14 days. Rats weighing 35±2.5 g were fed for 13 weeks with a diet incorporating 2500, 5000, 10,000 and 20,000 mg/kg (w/w) dry biomass for subchronic toxicity studies. Control consists of the diet without the dry biomass. Dietary feeding of M. rouxii biomass at any level showed no significant changes (p>0.05) in food intake, body weight, organs weight and serum enzymes. Macroscopic and microscopic observations revealed that the vital organs were unaffected by the feed containing the dry biomass. However, triglycerides and cholesterol levels in serum were decreased significantly (p<0.05) in the test rats. The results of this study suggests that feeding fungal mycelia containing oil is safe when fed to rats and also shows positive effects on controlling triglycerides and cholesterol.

Derivatization Ion Chromatography for the Determination of Monoethanolamine in Presence of Hydrazine in PHWR Steam-Water Circuits.

A simple, rapid and accurate method for the determination of monoethanolamine (MEA) in PHWR steam-water circuits has been developed. MEA is added in the feed water to provide protection against corrosion while hydrazine is added to scavenge dissolved oxygen. The quantitative determination of MEA in presence of hydrazine was accomplished using derivatization ion chromatography with conductometric detection in nonsuppressed mode. A Metrosep cation 1-2 analytical column and a Metrosep cartridge were used for cation separation. A mixture of 4 mM tartaric acid, 20% acetone and 0.05 mM HNO(3) was used as eluent. Acetone in the mobile phase leads to the formation of different derivatives with MEA and hydrazine. The interferences due Na(+) and NH(4) (+) were eliminated by adopting a simple pretreatment procedure employing OnGuard-H cartridge. The limit of detection limit of MEA was 0.1 µg mL(-1) and the relative standard deviation was 2% for the overall method. The recovery of MEA added was in the range 95%-102%. The method was applied to the determination of MEA in steam generator water samples.

Differential temperature effect on the production of enhanced gamma linolenic acid in Mucor rouxii CFR-G15.

Mucor rouxii CFR-G15, a locally isolated phycomycetous fungus, on cultivation at room temperature produced more than 30% (w/w) lipid in their dry cell weight, in which 14.2% accounted to be GLA content of the total fatty acids. It was observed that when incubation temperature lowered at 14°C, GLA content of the mycelium increased significantly (P<0.05) from 14.2% to 21.97%. In order to optimize the cultural conditions for high biomass and lipid production with high GLA content, the fungus was grown in association of two different temperatures and supply of additional glucose in culture medium. Maximum lipid and GLA were obtained 23.56 and 19.5% respectively, when the culture was grown at 28°C for four days and followed by addition of glucose (5%), and lowered the incubation temperature to 14°C for another four days. The presence of GLA in the oil obtained from M. rouxii CFR-G15 was confirmed by the gas chromatography-mass spectrometry. Gamma linolenic acid (GLA, n-6) is gaining importance in pharmaceutical and nutraceutical industries because of clinical evidence demonstrated that it has various beneficial effects in human health. In this paper temperature played a major role in enhancing the GLA content which has been described.

Safety evaluation of arachidonic acid rich Mortierella alpina biomass in albino rats--a subchronic study.

Safety evaluation of arachidonic acid rich Mortierella alpina biomass was carried out in Wistar rats by acute and subchronic oral toxicity studies. A preliminary acute toxicity study revealed that the biomass was safe at acute doses and that the LD50 exceeded 5000mg/kg BW, the highest dose used in the study. In subchronic study, rats were fed diet containing 0, 2500, 5000, 10,000, 20,000 and 30,000mg/kg, M. alpina biomass for a period of 13 weeks. Results indicated that biomass fortification had a positive influence on growth with no overt toxic effects on the survival, food consumption and body weight gain throughout the treatment interlude. The statistically significant changes in relative organ weights, serum biochemical and hematological indices in M. alpina fed groups' viz., higher relative weights of spleen, liver, brain and ovary in females, reduced hemoglobin concentration in males, elevated WBC counts at highest dose, reduction in serum triglycerides and increased alkaline phosphatase activity were not concomitant with pertinent histopathological changes and hence toxicologically inconsequential. No microscopic or macroscopic lesions attributable to the treatment were manifested in the experimental groups. The results of the present study strongly advocate the safety of M. alpina biomass in rats at levels used in the study.

Characterization of As (V), As (III) by selective reduction/adsorption on palladium nanoparticles in environmental water samples.

Hydrazine (HZ) and sodium borohydride (BH) are commonly used reagents for the production of palladium nanoparticles (PdNP) in aqueous solution and also for the reduction of arsenic from higher oxidation state to lower oxidation state. A methodology based on the quantitative adsorption of reduced arsenic species on PdNP generated in situ by BH and HZ is described to characterize As (V) and As (III) in environmental water samples. It was observed that PdNP obtained by BH gave quantitative recovery of As (V) and (III) and the PdNP obtained by HZ could account for As (III). The reduced palladium particles are collected and dissolved in minimum amount of nitric acid. The quantification of arsenic was carried out using GFAAS. Optimization of the experimental conditions and instrumental parameters were investigated in detail. The proposed procedure was validated by applying it for the determination of the content of total As in Certified Reference Material BND 301-02 (NPL, India). The detection limit of arsenic in environmental water samples was 0.029 microg L(-1) with an enrichment factor of 50. The relative standard deviation (R.S.D.) for 10 replicate measurements of 5 microg mL(-1) was 4.2%. The proposed method was successfully applied for the determination of sub ppm to ppm levels of arsenic (V), (III) in environmental water samples.

Bioremediation of trace cobalt from simulated spent decontamination solutions of nuclear power reactors using E. coli expressing NiCoT genes.

Removal of radioactive cobalt at trace levels (approximately nM) in the presence of large excess (10(6)-fold) of corrosion product ions of complexed Fe, Cr, and Ni in spent chemical decontamination formulations (simulated effluent) of nuclear reactors is currently done by using synthetic organic ion exchangers. A large volume of solid waste is generated due to the nonspecific nature of ion sorption. Our earlier work using various fungi and bacteria, with the aim of nuclear waste volume reduction, realized up to 30% of Co removal with specific capacities calculated up to 1 microg/g in 6-24 h. In the present study using engineered Escherichia coli expressing NiCoT genes from Rhodopseudomonas palustris CGA009 (RP) and Novosphingobium aromaticivorans F-199 (NA), we report a significant increase in the specific capacity for Co removal (12 microg/g) in 1-h exposure to simulated effluent. About 85% of Co removal was achieved in a two-cycle treatment with the cloned bacteria. Expression of NiCoT genes in the E. coli knockout mutant of NiCoT efflux gene (rcnA) was more efficient as compared to expression in wild-type E. coli MC4100, JM109 and BL21 (DE3) hosts. The viability of the E. coli strains in the formulation as well as at different doses of gamma rays exposure and the effect of gamma dose on their cobalt removal capacity are determined. The potential application scheme of the above process of bioremediation of cobalt from nuclear power reactor chemical decontamination effluents is discussed.