Elimination of mercury and organomercurials by nitrogen-fixing bacteria.
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Azotobacter↗
Biomedical subjects
A Mandal
Publications and source records attributed to A Mandal.
Mercury and organomercurial resistance in bacteria isolated from freshwater fish of wetland fisheries around Calcutta.
Mercury-resistant bacteria belonging to the genera Bacillus, Escherichia, Klebsiella, Micrococcus, Pseudomonas, Salmonella, Sarcina, Shigella, Staphylococcus and Streptococcus were isolated from gills and guts of fresh water fish collected from wetland fisheries around Calcutta, India, contaminated with mercury compounds. The total number of bacteria, as well as Hg-resistant bacteria, were always higher in guts than gills. Bottom-dwelling fish contained higher number of bacteria, including Hg-resistant bacteria, than surface and middle water dwelling fish. They belonged either to narrow-spectrum or to broad-spectrum Hg-resistant groups and they also possessed other heavy metal and antibiotic resistant properties. In the presence of toxic levels of HgCl(2), phenylmercuric acetate (PMA) and methylmercuric chloride (MMC), the lag in growth of the bacterial strains gradually increased with increasing concentration of Hg-compounds. Narrow-spectrum Hg-resistant bacterial strains volatilized only HgCl(2) from the liquid medium in the range of 64-89%, whereas the broad-spectrum group exhibited a high level of HgCl(2) (80-94%), PMA (72-84%) and MMC (64-80%) volatilizing capacity with inducible mercuric reductase and organomercurial lyase enzyme activities in their cell-free extracts. Cell-free extracts prepared from narrow-spectrum Hg-resistant bacterial strains induced by HgCl(2) exhibited Hg(+2)-dependent NADPH oxidation, indicating the presence of only mercuric reductase enzyme.
Journal Article↗
Changes in dorsal cochlear nucleus blood flow during noise exposure.
Changes in dorsal cochlear nucleus (DCN) blood flow during noise exposure were assessed using both intravital microscopy (IVM) and laser Doppler flowmetry (LDF). Mature Syrian golden hamsters were anesthetized, tracheotomized and implanted with a carotid artery catheter for monitoring blood pressure and infusion of fluorescent dye. An occipital craniectomy was performed and the cerebellum partly aspirated for access to the DCN. Fluorescent dye was infused to enhance observations of the DCN surface using a customized IVM. Red blood cell velocity, vessel diameter and blood pressure were continuously monitored. Subjects were presented with 110 dB SPL broad-band noise for 15 min. A second group was presented with the same protocol for laser Doppler assessment of blood-flow changes. Control groups included animals not exposed to noise using both IVM and laser Doppler measures. Additional control measurements were obtained for noise-exposed and control groups with laser Doppler measures obtained from the obex, a brainstem structure with no known auditory function. Arterioles of the DCN showed a low-frequency oscillatory pattern of red blood cell velocity in control animals and in baseline conditions of the noise-exposure group. Presentation of noise abolished these velocity oscillations. Additionally, significant decreases in both red blood cell velocity and vessel diameter were measured during stimulation. These microvascular measures recovered slightly during the post-stimulus period. Laser Doppler measures of the overall blood flow in the nucleus were consistent with IVM findings. Measurements from DCN and obex in groups not exposed to noise, and animals exposed to noise and measured from the obex, showed stable oscillatory flow. These data show exposure to noise eliminates oscillatory patterns of blood flow and induces decreases in vascular perfusion. Furthermore, these changes appear specific to the auditory structure studied.
Acoustic Stimulation↗
Rapid detection of acute appendicitis with Tc-99m-labeled intact polyvalent human immune globulin.
BACKGROUND: Acute appendicitis remains problematic for emergency clinicians. A rapid and definitive test is needed for detecting acute appendicitis before surgical intervention. The purpose of this clinical trial was to determine the efficacy of Tc-99m-labeled intact polyvalent human immune globulin (Tc-99m IgG) in the evaluation of acute appendicitis. STUDY DESIGN: Thirty-five patients with clinically suspected acute appendicitis were evaluated with Tc-99m IgG. After the intravenous injection of 25 mCi (92.5 MBq) of Tc-99m IgG, anterior flow, single photon emission computerized tomography (SPECT) and planar delayed images of the abdomen were obtained. Any abnormal focal uptake of Tc-99m IgG in the right lower quadrant was considered to be a positive scan. RESULTS: Twenty-one patients with a positive Tc-99m IgG scan underwent laparotomy and were found to have acute appendicitis. Of the 14 patients who had negative scans, 7 underwent surgery. In this series, Tc-99m IgG study yielded 21 true-positive, 12 true-negative, and 2 false-negative results with a sensitivity, specificity, and accuracy of 91%, 100%, and 94%, respectively. The positive and negative predictive values were 100% and 86%, respectively. There were no false-positive results. CONCLUSIONS: Tc-99m IgG scintigraphy can provide the clinicians a simple, rapid, and definitive test for the diagnosis of acute appendicitis.
Acute Disease↗
Vanadium-mediated chemoprotection against chemical hepatocarcinogenesis in rats: haematological and histological characteristics.
The trace element vanadium was investigated for its anti-neoplastic role in relation to haematological status, hepatic histopathology and histochemical analysis of glycogen in liver. Its impact on the survival of male Sprague-Dawley rats subjected to a two-stage hepatocarcinogenesis regimen was also assessed. Initiation was performed using a single intraperitoneal injection of diethylnitrosamine (DENA) (200 mg/kg) followed by promotion with phenobarbital (0.05%) in a basal diet. Vanadium supplementation as ammonium monovanadate at 0.5 ppm vanadium in drinking water was given ad libitum throughout the experiment (20 weeks), before the initiation (4 weeks), or during the promotional period (14 weeks). At the end of the study, there was a significant decrease in red blood cell count, haemoglobin content, haematocrit value, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, plasma volume change and total white cell count, with a concurrent alteration in lymphoid:myeloid ratio in DENA control animals compared with their normal counterparts. Vanadium supplementation throughout the study or before the initiation significantly reversed the DENA-induced alterations in most of the haematological indices. A single intraperitoneal injection of DENA also depleted the plasma albumin concentration, raised the plasma globulin content, and decreased the ratio of albumin to globulin. These altered features began to return to normal following vanadium supplementation. Supplementary vanadium also elicited substantial protection against DENA-mediated rat liver carcinogenesis. This was fairly evident from hepatic histology and evaluation of glycogen accumulation by periodic acid-Schiff reaction. The survival of DENA-treated animals was considerably increased in the presence of vanadium. The critical involvement of vanadium in modulating several factors associated with erythropoiesis under carcinogenic challenge may thus have a possible impact on the eventual increased survival of the host.
Administration, Oral↗
Volatilization of mercury by resting mercury-resistant bacterial cells.
The mercuric ion reduction system encoded by the Hg2+ inducible mer operon confers bacterial resistance to mercuric ion. The mer A gene product which is a FAD-containing enzyme catalyzes the reduction of Hg2+ to volatile elemental mercury with the help of intracellular thiols and NADPH as a cofactor (Schottel 1974; Summers and Silver 1978; Fox and Walsh 1982; Misra 1992). Our earlier studies have shown that growing cells of different mercury-resistant bacteria reduce Hg2+ compounds to Hg(O) (Ray et al. 1989; Pahan et al. 1990a; Gachhui et al. 1989). We have also shown the effect of thiol compounds and flavins on mercury-degrading enzyme activities in mercury-resistant bacteria (Pahan et al. 1990b). Here we report that resting cells of mercury-resistant bacteria survive in a buffer system for several hours, synthesize inducible mercury-degrading enzymes and volatilize mercury from a mercury-containing buffer system. We know of no information regarding studies of mercury-degrading enzymes in resting mercury-resistant bacterial cells.
Azotobacter↗
Technetium-99m IgG immunodetection of acute appendicitis in rats.
The efficacy of Tc-99m-labeled intact polyvalent human immune globulin (IgG) for the early localization and detection of acute appendicitis was evaluated by an animal model. Acute appendicitis was surgically produced in adult Sprague-Dawley white rats by ligating a 3-cm segment of the caecum and inoculating with E. coli. After 4-5 days, nuclear scintigraphy was performed following intravenous injection of 5 mCi of Tc-99m IgG via the tail vein. Appendiceal and colonic infections were clearly visualized by Tc-99m IgG scans within 30 min postinjection and confirmed by autopsy and tissue distribution data. With the exception of the liver, the kidneys, and the urinary bladder, abdominal tissue background activity was minimal. These findings suggest that Tc-99m-labeled intact IgG may have potential clinical application in the early detection and diagnosis of acute appendicitis in emergency medicine.
Acute Disease↗
Learning disabilities and poor motivation to achieve due to prolonged iodine deficiency.
The effect of prolonged iodine deficiency on learning and motivation was studied. One hundred male children--matched for age, socioeconomic status, and formal education--were selected from both severely iodine-deficient (SID) and mildly iodine-deficient (MID) villages. Mean urinary iodine excretion was significantly lower in the SID than in the MID group (219.84 +/- 57.52 compared with 449.14 +/- 32.31 nmol/L, P < 0.001). The serum thyroxine concentration was significantly lower (90.36 +/- 6.46 compared with 123.70 +/- 15.42 nmol/L, P< 0.001) and serum thyroid-stimulating hormone (TSH) was significantly higher in the SID group than in the MID group (6.23 +/- 0.34 compared with 4.85 +/- 0.28 mU/L, P< 0.01). The children were administered maze, verbal, and pictorial learning tasks and a test of motivation. The results showed that SID children are slow learners compared with MID children. In both groups the rate of learning over trials was superior in younger (aged 9-12 y) children although the initial performance of older (aged 12-15 y) children was better (P < 0.01). SID children scored significantly lower than MID children on the achievement motivation scale (P < 0.01). The results are suggestive of neural impairment as well as poor sociopsychologic stimulation, resulting in learning disability and lowered achievement motivation. Unless iodine nutrition is improved in the community as a whole, these abnormalities may prevent millions of children from the SID areas from achieving their full potential even if learning opportunities are made available to them.
Achievement↗
Usefulness of ELISA using antigen A60 in serodiagnosis of neurotuberculosis.
Anti-mycobacterial antibody to A60 antigen were quantified in the sera and cerebrospinal fluid (csf) samples of one hundred patients of neurotuberculosis and twenty non-tubercular controls by immunoenzymatic (ELISA) assay. Sixty three patients (63%) had "significant" antibody titres in serum and/or CSF samples. In contrast, none of the samples from the control group showed this level of antibody concentration. The evaluation of this assay in tuberculoma (group A, 79 cases) vis-a-vis tubercular meningitis or TBM (group B, 21 patients) revealed significant antibody levels in the former 46 (58.2%) in comparison to 17 (77.3%) in the latter group. A positive relationship was observed in the titres of anti-mycobacterial antibodies in serum and in CSF both in cases of tuberculoma and TBM. This study indicates the utility of A60 antigen ELISA assay in categorising these patients into tubercular aetiology specially in the absence of bacteriological isolation from CSF which still remains the gold standard diagnostic criterion.
Antibodies, Bacterial↗
Interleukin-1 and endothelin stimulate distinct species of diglycerides that differentially regulate protein kinase C in mesangial cells.
Diglycerides are phospholipid-derived second messengers that serve as cofactors for protein kinase C activation. We have previously shown that, in rat glomerular mesangial cells, the cytokine, interleukin-1 alpha, and the vasoactive peptide, endothelin, generate diglycerides from unique phospholipid precursors. However, neither the molecular species of these diglycerides nor their biological actions were determined. It is now hypothesized that interleukin-1- and endothelin-treated mesangial cells form distinct molecular species of diglycerides which may serve different roles as intracellular signaling molecules. Diglyceride molecular species were resolved and quantified by TLC and high performance liquid chromatography as diglyceride-[14C]acetate derivatives. Endothelin stimulates predominantly ester-linked species (diacylglycerols) in contrast to interleukin-1 which stimulates only ether-linked species (alkyl, acyl- and alkenyl,acylglycerols). In support of these data, interleukin-1-treated mesangial cells hydrolyze ethanolamine plasmalogens, vinyl ether-linked phospholipids. It has been reported that ether-linked, in contrast to ester-linked, diglyceride species do not activate protein kinase C activity. Thus, we next assessed membrane protein kinase C activity in endothelin- or interleukin-1-treated mesangial cells. Even though interleukin-1 has no effect upon basal protein kinase C activity, this cytokine, through the formation of ether-linked diglyceride second messengers, inhibits endothelin, platelet-activating factor, or arginine vasopressin-stimulated protein kinase C activity. We further demonstrate that ester-linked diacylglycerols but not alkyl,acyl- or alkenyl,acylglycerols substitute for phorbol esters in a cell-free protein kinase C assay. In addition, alkenyl,acylglycerols inhibit diacylglycerol-stimulated immunoprecipitated protein kinase C alpha activity in vitro and total protein kinase C activity in permeabilized mesangial cells ex vivo. Taken together, these data suggest that interleukin-1-induced formation of ether-linked diglycerides may physiologically serve to down-regulate receptor-mediated protein kinase C activity and that individual molecular species of diglycerides may serve different roles as intracellular signaling molecules.
Acetates↗
Enhanced elimination of HgCl2 from natural water by a broad-spectrum Hg-resistant Bacillus pasteurii strain DR2 in presence of benzene.
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Bacillus↗
Production of immunoglobulin G and G1 antibodies to cytoskeletal protein by lamina propria cells in ulcerative colitis.
BACKGROUND & AIMS: Recent studies suggest an autoantigenic role for tropomyosin-related protein(s) in ulcerative colitis (UC). This study examined whether immunoglobulin G and G1 subclass antibodies against tropomyosins are produced spontaneously by the lamina propria mononuclear cells (LPMCs) that infiltrate the inflamed UC tissue. METHODS: LPMCs were isolated from colonic biopsy specimens from 29 patients with UC, 15 with colonic Crohn's disease (CD), and 13 with non-inflammatory bowel disease (IBD). The autologous peripheral blood mononuclear cells (PBMCs) were obtained. Cells were cultured in vitro and unstimulated for 10 days. Spontaneous production of immunoglobulin G and G1 antibodies against tropomyosins was measured by enzyme-linked immunosorbent assays using highly enriched tropomyosins from skeletal muscle and colonic mucosa. RESULTS: The total immunoglobulin G produced by LPMCs from both patients with UC and CD was comparable but higher than from patients with non-IBD (P < 0.05). However, immunoglobulin G antibodies to tropomyosins were higher in patients with UC than in patients with CD (P < 0.04) and non-IBD (P < 0.02). LPMCs from patients with symptomatic UC produced higher immunoglobulin G antibodies to tropomyosins than patients with UC in remission (P < 0.03), symptomatic CD (P < 0.04), and non-IBD (P < 0.02). Immunoglobulin G antibodies to tropomyosins predominantly belonged to immunoglobulin G1 subclass. The autologous PBMCs showed comparable results. CONCLUSIONS: Immunoglobulin G antibodies predominantly belonging to immunoglobulin G1 subclass and reactive against tropomyosin-related protein(s) are spontaneously produced by LPMCs from the colonic mucosa in patients with UC.
Adolescent↗
Physiological potential of beta-carotene in prolonging the survival of the host bearing transplantable murine lymphoma.
beta-Carotene, when supplemented in diet, has been found to increase the survival period of mice bearing a transplantable tumor, Dalton's lymphoma. Tumor cell-count, body weight pattern, hematological parameters like total count showed marked alterations in a dose-responsive manner with beta-carotene administration when compared to their untreated counterparts. Decreased tumor cell proliferation is also reflected by increased hemoglobin levels of the host.
Animals↗
Sperm hyaluronidase activation by purified predominant and major basic human seminal coagulum proteins.
This study demonstrated that semenogelin I and II, the predominant and the major basic human seminal coagulum proteins respectively were shown to be potent activators of sperm hyaluronidase. These proteins stimulated the activity of bovine testicular hyaluronidase, goal cauda sperm hyaluronidase and human ejaculated sperm hyaluronidase. Human seminal plasma protein, which predominantly contains the basic degradation residues of the basic coagulum proteins and albumin (pI 4.7) and which is also basic at the assay pH 3.8, also showed activation of bovine testicular hyaluronidase while acidic pepsin (pI < 1.0) exhibited no such activation. The findings may be utilized as an assay method for comparative evaluation of specific activation units of the purified basic seminal coagulum proteins or their cleavage products and for quantifying the total basic protein (pI > 3.8) units in human seminal plasma. One unit of the coagulum protein was defined as the amount of the activator that increases 1 mIU of hyaluronidase activity by 50%. The specific activity of the 57 kDa and 75-79 kDa coagulum proteins, and that of serum albumin against Sigma bovine testicular hyaluronidase (type IV), were 11,447, 8600 and 6252 units per mg protein respectively. It was speculated that human seminal coagulum proteins may have an activation effect on spermatozoal hyaluronidase activity in vivo.
Animals↗
Study of oestrogen and progesterone receptors in meningiomas by a technique utilizing the binding hormones in a polymerized state.
Forty six cases of meningiomas were studied by utilizing oestrogen and progesterone hormone bound to fluroscent-iso-thiocynate (FITC) for the presence of oestrogen and progesterone receptors. Oestrogen receptors were present in 33% cases and only one fourth of these showed strong positivity. Progesterone receptors were positive in 41% cases, and more than half of these showed strong positivity. Thus this study revealed higher positivity rate for progesterone receptors than oestrogen receptors.
Adolescent↗
Mercury and organomercurial degrading enzymes in a broad-spectrum Hg-resistant strain of Bacillus pasteurii.
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Bacillus↗
Autoantibodies in sclerosing cholangitis against a shared peptide in biliary and colon epithelium.
BACKGROUND/AIMS: A strong association exists between ulcerative colitis and primary sclerosing cholangitis (PSC). Previously, the presence of a unique epitope shared by colon and biliary epithelial cells was shown by using the novel monoclonal antibody (MAb) 7E12H12 developed against a colonic epithelial protein. In the present study, the presence of circulating autoantibody in PSC against this peptide was examined. METHODS: Sera from 16 patients with PSC, 13 with primary biliary cirrhosis, 6 with secondary biliary stricture, and 6 with chronic liver diseases and 10 normal subjects were used. An inhibition immunoperoxidase assay using the 7E12H12 MAb was developed against sections of bile duct and gallbladder. Sera were also examined in an enzyme-linked immunosorbent assay (ELISA) against the gallbladder extract enriched in 7E12H12-reactive protein. RESULTS: About two thirds of the sera from patients with PSC blocked the binding of 7E12H12 MAb on the bile duct and gallbladder, whereas non-PSC sera did not. In the ELISA, 93% of PSC sera had circulating immunoglobulin G antibodies against the enriched gallbladder extract. The reactivity of sera from the PSC group was significantly (P < 0.01 to P < 0.0001) higher than in each of the non-PSC groups. CONCLUSIONS: Sera from patients with PSC contains autoantibodies against a cross-reactive peptide shared by colon and biliary epithelial cells.
Adult↗
Production of the Escherichia coli betaine-aldehyde dehydrogenase, an enzyme required for the synthesis of the osmoprotectant glycine betaine, in transgenic plants.
In several organisms osmotic stress tolerance is mediated by the accumulation of the osmoprotective compound glycine betaine. With the ambition to transfer the betaine biosynthetic pathway into plants not capable of synthesizing this osmoprotectant, the Escherichia coli gene betB encoding the second enzyme in the pathway, betaine-aldehyde dehydrogenase was introduced into Nicotiana tabacum. The betB structural gene was fused to the promoter of ats1a, a gene coding for the small subunit of Rubisco in Arabidopsis thaliana. Two types of constructs were made, either encoding the N-terminal transit peptide for chloroplast targeting or without the targeting signal for cytoplasmic localization of the BetB polypeptide. Analysis of transgenic N. tabacum plants harboring these constructs showed that in both cases the transgenes were expressed. Northern analysis of the plants demonstrated the accumulation of betB-related mRNA of the correct size. The production and processing of the corresponding polypeptides could be demonstrated by immunoblotting using polyclonal antisera raised against the BetB polypeptide. The transit peptide encoded by ats1a was able to direct BetB to the chloroplast, as suggested by the presence of the correctly processed BetB polypeptide in the chloroplast fraction. High betaine-aldehyde dehydrogenase activity was detected in transgenic plants, both in those where the chimeric gene product was targeted to the chloroplast and those where it remained in the cytoplasm. The transgenic tobacco acquired resistance to the toxic intermediate, betaine aldehyde, in the betaine biosynthetic pathway indicating that the bacterial enzyme is biologically active in its new host. Furthermore, these transgenic plants were able to convert exogenously supplied betaine aldehyde efficiently to glycine betaine.
Aldehyde Oxidoreductases↗