Phytoextraction of Soil Cobalt Using Hyperaccumulator Plants

A greenhouse study was conducted on phytoextraction of cobalt by nickel hyperaccumulators Alyssum murale and Alyssum corsicum and by two varieties of cobalt accumulator Nyssa sylvatica compared with the nonmetal accumulator crop plant Brassica juncea. The plants were grown on Sassafras sandy loam soil (<2 mg Co and 5 mg Ni/kg dry soil), amended with 1 mmol Co/kg dry soil (58.9 mg/kg), and two Ni smelter-contaminated soils, Quarry muck with 24 mg Co and 1720 mg Ni/kg dry soil and Welland loam with 37 mg Co and 2570 mg Ni/kg dry soil. All soils were adjusted to pH 6.5 to prevent Ni phytotoxicity. Of the five plant entries tested in the study, the two Alyssum species demonstrated the most promising Co phytoextraction results. In Co-amended Sassafras soil, the maximum concentration accumulated by Alyssum murale was 1320 mg Co/kg dry weight, which was almost 60 times higher than accumulation by crop plant Brassica juncea. At a single harvest after 60 days of growth, A. murale was able to extract more than 3% of Co from Co-amended soil. As expected, both Alyssum species accumulated up to 1% Ni on dry weight basis when grown on Ni-contaminated soils.

Nyssa sylvatica showed considerable Co accumulation; foliar Co concentration in the second harvest was as high as 800 mg/kg dry weight. The first few leaves that emerged were chlorotic, both in the Co-amended soil and Ni-contaminated soils, but with growth the signs of toxicity disappeared. In the Co amended soil, Co concentration in Nyssa sylvatica leaves was 30% of that found in shoots of Alyssum species, but an order of magnitude higher than that of Brassica juncea. The leaves accumulated a higher concentration compared with the stems.

Both Alyssum species and Nyssa sylvatica offer promise for phytoextraction of Co and ⁶⁰Co from contaminated or mineralized soils.     

Whole exome sequence analysis of Peters anomaly

Peters anomaly is a rare form of anterior segment ocular dysgenesis, which can also be associated with additional systemic defects. At this time, the majority of cases of Peters anomaly lack a genetic diagnosis. We performed whole exome sequencing of 27 patients with syndromic or isolated Peters anomaly to search for pathogenic mutations in currently known ocular genes. Among the eight previously recognized Peters anomaly genes, we identified a de novo missense mutation in PAX6, c.155G>A, p.(Cys52Tyr), in one patient. Analysis of 691 additional genes currently associated with a different ocular phenotype identified a heterozygous splicing mutation c.1025+2T>A in TFAP2A, a de novo heterozygous nonsense mutation c.715C>T, p.(Gln239*) in HCCS, a hemizygous mutation c.385G>A, p.(Glu129Lys) in NDP, a hemizygous mutation c.3446C>T, p.(Pro1149Leu) in FLNA, and compound heterozygous mutations c.1422T>A, p.(Tyr474*) and c.2544G>A, p.(Met848Ile) in SLC4A11; all mutations, except for the FLNA and SLC4A11 c.2544G>A alleles, are novel. This is the first study to use whole exome sequencing to discern the genetic etiology of a large cohort of patients with syndromic or isolated Peters anomaly. We report five new genes associated with this condition and suggest screening of TFAP2A and FLNA in patients with Peters anomaly and relevant syndromic features and HCCS, NDP and SLC4A11 in patients with isolated Peters anomaly.     

Chromosome phylogeny of the subfamily Pitheciinae (Platyrrhini,Primates) by classic cytogenetics and chromosome painting

Background  

The New World monkey (Platyrrhini) subfamily Pitheciinae is represented by the genera Pithecia, Chiropotes and Cacajao. In this work we studied the karyotypes of Pithecia irrorata (2n = 48) and Cacajao calvus rubicundus (2n = 45 in males and 2n = 46 in females) by G- and C-banding, NOR staining and chromosome painting using human and Saguinus oedipus whole chromosome probes. The karyotypes of both species were compared with each other and with Chiropotes utahicki (2n = 54) from the literature.     

Hyperlipidemia is a major determinant of neointimal formation in LDL receptor-deficient mice

LDL receptor-deficient (LDLR(-/-)) mice exhibit mild hyperlipidemia on a chow diet but develop severe hyperlipidemia on a high fat diet. In this study, we investigated neointimal formation after removal of the endothelium when LDLR(-/-) mice were fed chow or a Western diet containing 42% fat, 0.15% cholesterol, and 19.5% casein. At 10 weeks of age, female mice underwent endothelial denudation of the left common carotid artery. Two weeks after injury, neointimal formation was barely detectable in the injured vessel when mice developed mild hyperlipidemia on the chow diet. In contrast, neointimal lesions were obvious when mice developed severe hyperlipidemia on the Western diet. Immunohistochemical and histological analyses demonstrated the presence of macrophage foam cells and smooth muscle cells in neointimal lesions. The injured artery also exhibited a significant increase in medial area on the Western diet. Plasma levels of MCP-1 and soluble VCAM-1 were significantly elevated by feeding of the Western diet. These data indicate that hyperlipidemia aggravates neointimal growth in LDLR(-/-) mice by promoting foam cell formation and inflammation.     

Soil moisture effects on uptake of metals by Thlaspi, Alyssum, and Berkheya

Most commonly used hyperaccumulator plants for phytoextraction of metals evolved on soils where moisture is limited throughout much of the year. As these plant species are commercialized for use, they are frequently moved from the point of evolution to locations where environmental conditions may be significantly different. Greatest among these potential differences is soil moisture. The objective of this study was therefore to determine whether these plants could grow in soils with much higher soil moisture and whether they would continue to hyperaccumulate metals as soils approach saturation. We examined extractable soil metal concentrations, plant growth, and metal accumulation for the Ni hyperaccumulators, Alyssum murale and Berkheya coddii and the Zn hyperaccumulators Thlaspi caerulescens cultivars AB300 and AB336. Non-hyperaccumulating control species for each were also examined. In general, extractable soil concentrations of Ni decreased with increasing soil moisture content. Few significant effects related to Zn extractability were observed for any of the soil moisture treatments. The biomass of all tested species was generally greater at higher soil moisture and inhibited at low soil moisture. Further, plants accumulated large amounts of metals from soil at higher soil moisture. Highest foliar concentrations of Zn or Ni were found at the two highest WHCs of 80 and 100%. These results show that hyperaccumulators grow well under conditions of high soil moisture content and that they continue to hyperaccumulate metals. Thus, growing Thlaspi, Alyssum, and Berkheya for commercial phytoextraction under nonnative conditions is appropriate and suggests that this technology may be applied to a wide and diverse range of soil types, climatic conditions, and irrigation regimes.     

Direct effects of nitroprusside do not alter gas exchange in canine oleic acid edema

The authors investigated why intrapulmonary shunt (QS/QT) increases with sodium nitroprusside (SNP) in canine oleic acid pulmonary edema. To determine the effects of flow alone on QS/QT, a peripheral arteriovenous fistula with a variable resistor was employed to increase cardiac output (Q) 26 and 52% above base line in a stepwise fashion (P less than 0.01). To examine the direct effects of SNP, distinct from changes in flow, the drug was given to produce matched increments in Q in each dog (P less than 0.01). To control for time, base-line measurements were obtained before and after each intervention, the sequence of which was alternated. At each increment in Q, SNP and the arteriovenous fistula increased QS/QT a similar amount. The mixed venous O2 tension (P-vO2) followed Q similarly in each group. Pulmonary vascular resistance (PVR) fell more (P less than 0.01) with SNP than with the arteriovenous fistula at identical Q and P-vO2. The authors conclude that, in this model, a direct pharmacological effect of SNP does not contribute to the deterioration in QS/QT. In fact, SNP exerts a pulmonary vasoactive effect that does not adversely affect gas exchange.     

Molecular modeling and analysis of human and plant endo-β-N-acetyl- glucosaminidases for mutations effects on function

Endo- β-N-acetylgucosaminidases (ENGases) are the enzymes that catalyze both hydrolysis and transglycosylation reactions. It is of interest to study ENGases because of their ability to synthesize glycopeptides. Homology models of Human, Arabidopsis thaliana and Sorghum ENGases were developed and their active sites marked based on information available from Arthrobacter protophormiae (PDB ID: 3FHQ) ENGase. Further, these models were docked with the natural substrate GlcNAc-Asn and the inhibitor Man₃GlcNAc-thiazoline. The catalytic triad of Asn, Glu and Tyr (N171, E173 and Y205 of bacteria) were found to be conserved across the phyla. The crucial Y299F mutation showing 3 times higher transglycosylation activity than in wild type Endo-A is known. The hydrolytic activity remained unchanged in bacteria, while the transglycosylation activity increased. This Y to F change is found to be naturally evolved and should be attributing higher transglycosylation rates in human and Arabidopsis thaliana ENGases. Ligand interactions Ligplots revealed the interaction of amino acids with hydrophobic side chains and polar uncharged side chain amino acids. Thus, structure based molecular model-ligand interactions provide insights into the catalytic mechanism of ENGases and assist in the rational engineering of ENGases.     

PKC-dependent regulation of transepithelial resistance: roles of MLC and MLC kinase

The mechanisms by which protein kinase C (PKC) activationresults in increased transepithelial resistance (TER) are unknown [G. Hecht, B. Robinson, and A. Koutsouris. Am.J. Physiol. 266 (Gastrointest. LiverPhysiol. 29): G214-G221, 1994]. We havepreviously shown that phosphorylation of the regulatory light chain ofmyosin II (MLC) is associated with decreases in TER and have suggested that contraction of the perijunctional actomyosin ring (PAMR) increasestight junction (TJ) permeability [J. R. Turner, B. K. Rill, S. L. Carlson, D. Carnes, R. Kerner, R. J. Mrsny, and J. L. Madara.Am. J. Physiol. 273 (Cell Physiol. 42): C1378-C1385, 1997]. We therefore hypothesized that PKC activation alters TER via relaxation of the PAMR. Activation of PKC by the phorbol ester phorbol 12-myristate 13-acetate (PMA) resulted in a progressive dose-dependent increase in TER that was apparent within 15 min (111%of controls) and maximal within 2 h (142% of controls). Similarincreases were induced by a diacylglycerol analog, and the effects ofboth PMA and the diacylglycerol analog were prevented by the PKCinhibitor bisindolylmaleimide I. PMA treatment caused progressivedecreases in MLC phosphorylation, by 12% at 15 min and 41% at 2 h.Phosphorylation of MLC kinase (MLCK) increased by 64% within 15 min ofPMA treatment and was stable over 2 h (51% greater than that ofcontrols). Thus increases in MLCK phosphorylation preceded decreases inMLC phosphorylation. These data suggest that PKC regulates TER viadecreased phosphorylation of MLC, possibly due to inhibitoryphosphorylation of MLCK. The decreased phosphorylation of MLC likelyreduces PAMR tension, leading to decreased TJ permeability.