A chemically induced new pea (Pisum sativum) mutant SGECdt with increased tolerance to, and accumulation of, cadmium

BACKGROUND AND AIMS: To date, there are no crop mutants described in the literature that display both Cd accumulation and tolerance. In the present study a unique pea (Pisum sativum) mutant SGECd(t) with increased Cd tolerance and accumulation was isolated and characterized. METHODS: Ethylmethane sulfonate mutagenesis of the pea line SGE was used to obtain the mutant. Screening for Cd-tolerant seedlings in the M2 generation was performed using hydroponics in the presence of 6 microm CdCl2. Hybridological analysis was used to identify the inheritance of the mutant phenotype. Several physiological and biochemical characteristics of SGECd(t) were studied in hydroponic experiments in the presence of 3 microm CdCl2, and elemental analysis was conducted. KEY RESULTS: The mutant SGECd(t) was characterized as having a monogenic inheritance and a recessive phenotype. It showed increased Cd concentrations in roots and shoots but no obvious morphological defects, demonstrating its capability to cope well with increased Cd levels in its tissues. The enhanced Cd accumulation in the mutant was accompanied by maintenance of homeostasis of shoot Ca, Mg, Zn and Mn contents, and root Ca and Mg contents. Through the application of La(+3) and the exclusion of Ca from the nutrient solution, maintenance of nutrient homeostasis in Cd-stressed SGECd(t) was shown to contribute to the increased Cd tolerance. Control plants of the mutant (i.e. no Cd treatment) had elevated concentrations of glutathione (GSH) in the roots. Through measurements of chitinase and guaiacol-dependent peroxidase activities, as well as proline and non-protein thiol (NPT) levels, it was shown that there were lower levels of Cd stress both in roots and shoots of SGECd(t). Accumulation of phytochelatins [(PCcalculated) = (NPT)-(GSH)] could be excluded as a cause of the increased Cd tolerance in the mutant. CONCLUSIONS: The SGECd(t) mutant represents a novel and unique model to study adaptation of plants to toxic heavy metal concentrations.     

Caveolin-1 overexpression correlates with tumour progression markers in pancreatic ductal adenocarcinoma

The assessment of caveolin-1 (Cav-1) as a marker of tumor aggressiveness in pancreatic ductal adenocarcinoma (PDAC). In this study, we examined the expression of Cav-1 in 34 human PDAC tissue samples and the associated peritumoral tissues by immunohistochemistry and western blot. Additionally, we correlated Cav-1 expression with other tissue (Ki-67, p53) and serum (CA 19-9) tumor markers. In the tumor-derived tissue, both tumor cells and blood vessels expressed Cav-1. In contrast, in peritumoral tissue, Cav-1 expression was confined mainly to blood vessels and was only occasionally expressed in ductal or parenchymal cells. Western blot analysis confirmed the overexpression of Cav-1 in pancreatic tumors compared with peritumoral tissue. Cav-1 expression in tumor tissues was correlated with both the Ki-67 LI (r = 0.95, P < 0.0001) and p53 expression (χ2 = 9.91, P < 0.005). Overexpression of Cav-1 was associated with tumor size, grade and stage and Cav-1 expression in tumors was correlated with an increased serum level of CA 19-9 (r = 0.795, P < 0.001). Based on the results of this study, the inclusion of Cav-1 in a putative panel of biomarkers predicting pancreatic cancer aggressiveness is warranted.     

Green flavoprotein from P. leiognathi: Purification,characterization and identification as the product of the lux G(N) gene

A green flavoprotein (GFP) was isolated and purified to homogeneity from Photobacterium leiognathi, strain 208. GFP is a homodimer of molecular weight 54000 and contains two molecules of an unusual flavin per molecule of protein. Various biochemical characteristics including isoelectric point, trypsin and chymotrypsin degradation, SDS and temperature influence on subunit dissociation and the dissociation of the flavin chromophore, were investigated. The sequence of 23 N-terminal amino acids was determined and found to be concurrent with the N-terminal amino acids was determined and found to be concurrent with the N-terminal amino acid sequence encoded by the lux G (N) gene of P. leiognathi. This fact suggests that GFP is a structural component of the Photobacterium luminescence system.     

HDL Size is More Accurate than HDL Cholesterol to Predict Carotid Subclinical Atherosclerosis in Individuals Classified as Low Cardiovascular Risk

Background

Misclassification of patients as low cardiovascular risk (LCR) remains a major concern and challenges the efficacy of traditional risk markers. Due to its strong association with cholesterol acceptor capacity, high-density lipoprotein (HDL) size has been appointed as a potential risk marker. Hence, we investigate whether HDL size improves the predictive value of HDL-cholesterol in the identification of carotid atherosclerotic burden in individuals stratified to be at LCR.

Methods and Findings

284 individuals (40–75 years) classified as LCR by the current US guidelines were selected in a three-step procedure from primary care centers of the cities of Campinas and Americana, SP, Brazil. Apolipoprotein B-containing lipoproteins were precipitated by polyethylene glycol and HDL size was measured by dynamic light scattering (DLS) technique. Participants were classified in tertiles of HDL size (<7.57; 7.57–8.22; >8.22 nm). Carotid intima-media thickness (cIMT) <0.90 mm (80^th percentile) was determined by high resolution ultrasonography and multivariate ordinal regression models were used to assess the association between cIMT across HDL size and levels of lipid parameters. HDL-cholesterol was not associated with cIMT. In contrast, HDL size >8.22 nm was independently associated with low cIMT in either unadjusted and adjusted models for age, gender and Homeostasis Model Assessment 2 index for insulin sensitivity, ethnicity and body mass index (Odds ratio 0.23; 95% confidence interval 0.07–0.74, p = 0.013).

Conclusion

The mean HDL size estimated with DLS constitutes a better predictor for subclinical carotid atherosclerosis than the conventional measurements of plasma HDL-cholesterol in individuals classified as LCR.     

Intraspecies Genomic Diversity and Long-Term Persistence of Bifidobacterium longum

Members of genus Bifidobacterium are Gram-positive bacteria, representing a large part of the human infant microbiota and moderately common in adults. However, our knowledge about their diversity, intraspecific phylogeny and long-term persistence in humans is still limited. Bifidobacterium longum is generally considered to be the most common and prevalent species in the intestinal microbiota. In this work we studied whole genome sequences of 28 strains of B. longum, including 8 sequences described in this paper. Part of these strains were isolated from healthy children during a long observation period (up to 10 years between isolation from the same patient). The three known subspecies (longum, infantis and suis) could be clearly divided using sequence-based phylogenetic methods, gene content and the average nucleotide identity. The profiles of glycoside hydrolase genes reflected the different ecological specializations of these three subspecies. The high impact of horizontal gene transfer on genomic diversity was observed, which is possibly due to a large number of prophages and rapidly spreading plasmids. The pan-genome characteristics of the subspecies longum corresponded to the open pan-genome model. While the major part of the strain-specific genetic loci represented transposons and phage-derived regions, a large number of cell envelope synthesis genes were also observed within this category, representing high variability of cell surface molecules. We observed the cases of isolation of high genetically similar strains of B. longum from the same patients after long periods of time, however, we didn’t succeed in the isolation of genetically identical bacteria: a fact, reflecting the high plasticity of microbiota in children.     

Effect of experimental gingivitis induction and erythritol on the salivary metabolome and functional biochemistry of systemically healthy young adults

Introduction

Understanding the changes occurring in the oral ecosystem during development of gingivitis could help improve prevention and treatment strategies for oral health. Erythritol is a non-caloric polyol proposed to have beneficial effects on oral health.

Objectives

To examine the effect of experimental gingivitis and the effect of erythritol on the salivary metabolome and salivary functional biochemistry.

Methods

In a two-week experimental gingivitis challenge intervention study, non-targeted, mass spectrometry-based metabolomic profiling was performed on saliva samples from 61 healthy adults, collected at five time-points. The effect of erythritol was studied in a randomized, controlled trial setting. Fourteen salivary biochemistry variables were measured with antibody- or enzymatic activity-based assays.

Results

Bacterial amino acid catabolites (cadaverine, N-acetylcadaverine, and α-hydroxyisovalerate) and end-products of bacterial alkali-producing pathways (N-α-acetylornithine and γ-aminobutyrate) increased significantly during the experimental gingivitis. Significant changes were found in a set of 13 salivary metabolite ratios composed of host cell membrane lipids involved in cell signaling, host responses to bacteria, and defense against free radicals. An increase in mevalonate was also observed. There were no significant effects of erythritol. No significant changes were found in functional salivary biochemistry.

Conclusions

The findings underline a dynamic interaction between the host and the oral microbial biofilm during an experimental induction of gingivitis.

     

Structure of internalin,a major invasion protein of Listeria monocytogenes,in complex with its human receptor E-cadherin

Listeria monocytogenes, a food-borne bacterial pathogen, enters mammalian cells by inducing its own phagocytosis. The listerial protein internalin (InlA) mediates bacterial adhesion and invasion of epithelial cells in the human intestine through specific interaction with its host cell receptor E-cadherin. We present the crystal structures of the functional domain of InlA alone and in a complex with the extracellular, N-terminal domain of human E-cadherin (hEC1). The leucine rich repeat (LRR) domain of InlA surrounds and specifically recognizes hEC1. Individual interactions were probed by mutagenesis and analytical ultracentrifugation. These include Pro16 of hEC1, a major determinant for human susceptibility to L. monocytogenes infection that is essential for intermolecular recognition. Our studies reveal the structural basis for host tro-pism of this bacterium and the molecular deception L. monocytogenes employs to exploit the E-cadherin system.     

Dihydro-resveratrol—A potent dietary polyphenol

Dihydro-resveratrol (dihydro-R), a prominent polyphenol component of red wine, has a profound proliferative effect on hormone-sensitive tumor cell lines such as breast cancer cell line MCF7. We found a significant increase in MCF7 tumor cells growth rates in the presence of picomolar concentrations of this compound. The proliferative effect of dihydro-R was not observed in cell lines that do not express hormone receptors (MDA-MB-231, BT-474, and К-562).     

Highly selective c-Jun N-terminal kinase (JNK) 3 inhibitors with in vitro CNS-like pharmacokinetic properties II. Central core replacement

In this Letter, we describe the evolution of selective JNK3 inhibitors from 1, that routinely exhibit >10-fold selectivity over JNK1 and >1000-fold selectivity over related MAPKs. Strong SAR was found for substitution of the naphthalene ring, as well as for inhibitors adopting different central scaffolds. Significant potency gains were appreciated by inverting the polarity of the thione of the parent triazolothione 1, resulting in potent compounds with attractive pharmacokinetic profiles.