Arsenic tolerance and phytoremediation potential of Conocarpus erectus L. and Populus deltoides L.

The present study was conducted to explore arsenic (As) tolerance and phytostabilization potential of the two tree species, buttonwood (Conocarpus erectus) and eastern cottonwood (Populus deltoides). Both plant species were grown in pots and were exposed to various soil As levels (control, 5, 10, 15, and 20 mg kg^?1). The plants were harvested after 9 months for the evaluation of growth parameters as well as root and shoot As concentrations. With increasing soil As levels, plant height stress tolerance index (PHSTI) was significantly decreased in both tree species, whereas root length stress tolerance index (RLSTI) and dry matter stress tolerance index (DMSTI) were not affected. Root and shoot As concentrations significantly increased in both tree species with increasing soil As levels. Translocation factor and bioconcentration factor were less than 1.0 for both plant species. This study revealed that both tree species are non-hyperaccumulators of As, but they could be used for phytostabilization of As-contaminated soils.     

Comparative effect of calcium and EDTA on arsenic uptake and physiological attributes of Pisum sativum

In this study, we determined the effect of ethylenediaminetetraacetic acid (EDTA) and calcium (Ca) on arsenic (As) uptake and toxicity to Pisum sativum. Plants were treated with three levels of As (25, 125, and 250 µM) in the presence and absence of three levels of Ca (1, 5, and 10 mM) and EDTA (25, 125, and 250 µM). Exposure to As caused an overproduction of hydrogen peroxide (H₂O₂) in roots and leaves, which induced lipid peroxidation and decreased pigment contents. Application of both Ca and EDTA significantly reduced As accumulation by pea, Ca being more effective in reducing As accumulation. Both Ca and EDTA enhanced As-induced H₂O₂ production, but reduced lipid peroxidation. In the case of pigment contents, EDTA significantly reduced pigment contents, whereas Ca significantly enhanced pigment contents compared to As alone. The effect of As treatment in the presence and absence of EDTA and Ca was more pronounced in younger leaves compared to older leaves. The effect of amendments varied greatly with their applied levels, as well as type and age of plant organs. Importantly, due to possible precipitation of Ca-As compounds, the soils with higher levels of Ca ions are likely to be less prone to food chain contamination.     

Hybrid Pharmacophoric Approach in the Design and Synthesis of Coumarin Linked Pyrazolinyl as Urease Inhibitors,Kinetic Mechanism and Molecular Docking

The current research article reports the synthesis of coumarinyl pyrazolinyl thioamide derivatives and their biological activity as inhibitors of jack bean urease. The coumarinyl pyrazolinyl thioamides were synthesized by reacting thiosemicarbazide with newly synthesized chalcones to afford the products in good yields and the synthesized compounds were purified by recrystallization. Coumarinyl pyrazolinyl thioamide derivatives 5a  –  5q showed significant activity against Urease enzyme and also exhibited good antioxidant potential. The compound 3‐(2‐oxo‐2H‐chromen‐3‐yl)‐5‐phenyl‐4,5‐dihydro‐1H‐pyrazole‐1‐carbothioamide ( 5n ) was found to be superior agent in the series with an IC₅₀ = 0.358 ± 0.017 μm compared to standard thiourea with an IC₅₀ = 4720 ± 174 μm . To undermine the binding mode of inhibition kinetic studies were performed for most potent derivative and it was found that compound 5n inhibits urease enzyme by non‐competitive mode of inhibition. Molecular docking studies were carried out to delineate the binding affinity of the synthesized derivatives.     

DBT desulfurization by decorating Rhodococcus erythropolis IGTS8 using magnetic Fe3O4 nanoparticles in a bioreactor

Today, crude oil is an important source of energy and environmental contamination due to the continued use of petroleum products is a matter or urgent concern. In this work, two technological platforms, namely, the use of a robust desulfurizing bacteria and the use of nanotechnology to decorate the surface of the bacteria with nanoparticles (NP), were combined to enhance biodesulfurization (BDS). BDS is an ecologically friendly method for desulfurizing petroleum products while avoiding damage to the hydrocarbons due to the high temperatures normally associated with physical desulfurization methods. First, a bacterium known to be a good organism for desulfurization (Rhodococcus erythropolis IGTS8) was employed in cell culture to remove a recalcitrant sulfur molecule from a common sulfur‐containing compound found in crude petroleum products (dibenzothiophene). 2‐Hydroxybiphenyl (2‐HBP) produced as a consequence of the BDS of dibenzothiophene was determined using Gibbs’ assay. The synthesized NP were characterized by field emission scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction spectroscopy, and vibrating sample magnetometer. The field emission scanning electron microscope and transmission electron microscopy images showed the size of the NP is 7–8 nm. The decorated cells had a long lag phase, but the growth continued until 148 h (at OD₆₀₀ = 3.408) while the noncoated bacteria grow until 96 h before entering the stationary phase at OD₆₀₀ = 2.547. Gibbs’ assay results showed that production of 2‐HBP by decorated cells was 0.210 mM at t = 148 h, while 2‐HBP production by nondecorated cells was 0.182 mM at t = 96 h. Finally, the experiments were repeated in a fermenter.     

Long-chain acyl-CoA dehydrogenase is a key enzyme in the mitochondrial beta-oxidation of unsaturated fatty acids

The first reaction of mitochondrial beta-oxidation, which is catalyzed by acyl-CoA dehydrogenases, was studied with unsaturated fatty acids that have a double bond either at the 4,5 or 5,6 position. The CoA thioesters of docosahexaenoic acid, arachidonic acid, 4,7,10-cis-hexadecatrienoic acid, 5-cis-tetradecenoic acid, and 4-cis-decenoic acid were effectively dehydrogenated by both rat and human long-chain acyl-CoA dehydrogenases (LCAD), whereas they were poor substrates of very long-chain acyl-CoA dehydrogenases (VLCAD). VLCAD, however, was active with CoA derivatives of long-chain saturated fatty acids or unsaturated fatty acids that have double bonds further removed from the thioester function. Although bovine LCAD effectively dehydrogenated 5-cis-tetradecenoyl-CoA (14:1) and 4,7,10-cis-hexadecatrienoyl-CoA, it was nearly inactive toward the other unsaturated substrates. The catalytic efficiency of rat VLCAD with 14:1 as substrate was only 4% of the efficiency determined with tetradecanoyl-CoA, whereas LCAD acted equally well on both substrates. The conclusion of this study is that LCAD serves an important, if not essential function in the beta-oxidation of unsaturated fatty acids.     

Functional responses and costimulator dependence of memory CD4+ T cells

To examine the functional characteristics of memory CD4+ T cells, we used an adoptive transfer system to generate a stable population of Ag-specific memory cells in vivo and compared their responses to Ag with those of a similar population of Ag-specific naive cells. Memory cells localized to the spleen and lymph nodes of mice and exhibited extremely rapid recall responses to Ag in vivo, leaving the spleen within 3-5 days of Ag encounter. Unlike their naive counterparts, memory cells produced effector cytokines (IFN-gamma, IL-4, IL-5) within 12-24 h of Ag exposure and did not require multiple cycles of cell division to do so. Memory cells proliferated at lower Ag concentrations than did naive cells, were less dependent on costimulation by B7 molecules, and independent of costimulation by CD40. Furthermore, effector cytokine production by memory cells also occurred in the absence of either B7 or CD40 costimulation. Lastly, memory cells were resistant to tolerance induction. Together, these findings suggest that the threshold for activation of memory CD4+ cells is lower than that of naive cells. This would permit memory cells to rapidly express their effector functions in vivo earlier in the course of a secondary immune response, when the levels of Ag and the availability of costimulation may be relatively low.     

Chemokine monokine induced by IFN-gamma/CXC chemokine ligand 9 stimulates T lymphocyte proliferation and effector cytokine production

Monokine induced by IFN-gamma (MIG; CXC chemokine ligand (CXCL)9) is important in T lymphocyte recruitment in organ transplantation. However, it is not known whether this chemokine, in addition to its chemotactic properties, exerts any effect on T lymphocyte effector functions. For in vivo studies, we used a previously characterized murine model of chronic rejection. The recipient mice were treated with anti-MIG/CXCL9 Ab; graft-infiltrating cells were analyzed for IFN-gamma production. For in vitro studies, exogenous CXCR3 ligands were added to CD4 lymphocytes in MLRs, and the proliferative responses were measured. Separate experiments quantitated the number of IFN-gamma-producing cells in MLRs by ELISPOT. Neutralization of MIG/CXCL9, in the in vivo model, resulted in significant reduction in the percentage of IFN-gamma-producing graft-infiltrating T lymphocytes. In vitro experiments demonstrated that 1) exogenous MIG/CXCL9 stimulated CD4 lymphocyte proliferation in a MHC class II-mismatched MLR, 2) MIG/CXCL9 also increased the number of IFN-gamma-producing CD4 lymphocytes in ELISPOT, 3) neutralization of MIG/CXCL9 in MLR reduced T lymphocyte proliferation, 4) IFN-gamma-inducible protein 10/CXCL10 and IFN-inducible T cell alpha chemoattractant/CXCL11 had similar effects on T lymphocyte proliferation, 5) MIG/CXCL9 stimulated T lymphocyte proliferation in MHC class I- and total MHC-mismatched MLRs, 6) neutralization of CXCR3 reduced MIG/CXCL9-induced T lymphocyte proliferation and the number of IFN-gamma-positive spots on ELISPOT, and 7) the proliferative effects of MIG/CXCL9 were mediated via an IL-2-independent pathway and were controlled by IFN-gamma. This study demonstrates that MIG/CXCL9 stimulates T lymphocyte proliferation and effector cytokine production, in addition to its chemotactic effects. This novel observation expands our current understanding of MIG/CXCL9 biology beyond that of mediating T cell trafficking.     

Assessment of DHPLC usefulness in the genotyping of GSTP1 exon 5 SNP: comparison to the PCR-RFLP method

Single-nucleotide polymorphism (SNP) analysis can be performed by several methods such as PCR-RFLP, real time PCR and mass spectrometry. Denaturating High Pressure Liquid Chromatography (DHPLC) analysis allows the detection of DNA mutations in heteroduplex samples. GSTP1 exon 5 gene presents a single-nucleotide polymorphism (a to g) that results into an amino-acid substitution (Ile to Val). Ile and Val variants are identified respectively by a and b alleles. This polymorphism affects enzyme activity and is highly frequent within Caucasian populations and therefore widely studied in the context of SNP related to cancer susceptibility. Our goal was to evaluate DHPLC usefulness in detecting a well-known SNP in comparison to PCR-RFLP, in the field of molecular epidemiological studies. Fifty Caucasian people were genotyped by both methods. Heterozygous samples were identified easily at two temperatures using the DHPLC method. Discrimination between a/a and b/b homozygous genotypes was done by pooling every homozygous sample with a known a/a sample. Our genotyping using both methods resulted in the characterisation of 32 (64%) a/a homozygous, 18 (36%) a/b heterozygous and 5 (10%) b/b homozygous. All samples were also identically genotyped by the two methods. Our results show that DHPLC is a good alternative to classical PCR-RFLP method in genotyping SNPs. Advantages of this chromatographic method were no restriction site needed and a reduced technical time thanks to an automated injection. Moreover, unlike classical RFLP gel analysis, DHPLC chromatograms provided objective criteria for sample classification.     

Cloning of structural genes involved in riboflavin synthesis of the yeast Candida famata

The riboflavin overproducing mutants of the flavinogenic yeast Candida famata isolated by conventional selection methods are used for the industrial production of vitamin B2. Recently, a transformation system was developed for C. famata using the leu2 mutant as a recipient strain and Saccharomyces cerevislae LEU2 gene as a selective marker. In this paper the cloning of C. famata genes for riboflavin synthesis on the basis of developed transformation system for this yeast species is described. Riboflavin autotrophic mutants were isolated from a previously selected C. famata leu2 strain. C. famata genomic DNA library was constructed and used for cloning of the corresponding structural genes for riboflavin synthesis by complementation of the growth defects on a medium without leucine and riboflavin. As a result, the DNA fragments harboring genes RIB1, RIB2, RIB5, RIB6 and RIB7 encoding GTP cyclohydrolase, reductase, dimethylribityllumazine synthase, dihydroxybutanone phosphate synthase and riboflavin synthase, were isolated and subsequently subcloned to the smallest possible fragments. The plasmids with these genes successfully complemented riboflavin auxotrophies of the corresponding mutants of another flavinogenic yeast Pichia guilliermondii. This suggested that C. famata structural genes for riboflavin synthesis and not some of the supressor genes were cloned.     

Prevalence of congenital hypothyroidism in Isfahan, Iran: results of a survey on 20,000 neonates

AIMS: To evaluate the prevalence of congenital hypothyroidism (CH) in a screening program performed for the first time in Isfahan, Iran. METHODS: From May 2002 to December 2002, T4 and TSH serum concentrations of 20,000 3- to 7-day-old newborns, born in all 17 hospitals of the city, were measured by radioimmunoassay and immunoradiometric assay, respectively. The newborns with abnormal screening results (TSH >20 mIU/l, T4 <6.5 microg/dl and based on the weight) were re-examined. RESULTS: Of 531 recalled subjects (recall rate 2.6%), 54 were confirmed to be hypothyroid, showing a prevalence of 1:370 for CH. CONCLUSION: Considering the high frequency of CH, the necessity of implementing a routine screening program in the healthcare system of Isfahan Province is emphasized.