Chromium,Copper, and Arsenic Concentrations in Soil Underneath CCA-Treated Wood Structures

Soils below nine structures (decks and foot bridges) in Florida were examined to evaluate potential impacts from chromated copper arsenate (CCA), a common wood preservative. Eight of the nine structures were confirmed to have been treated with CCA. Soils collected were evaluated for arsenic, chromium, and copper concentrations as well as pH, volatile solids content and particle size distribution. Two types of soil samples were collected: a soil core and surface soil samples (upper 2.5 cm). One soil core was collected from below each deck and one control core was collected from an area removed from one of the structures. Eight or nine surface soil samples were collected in a grid-like fashion from beneath each structure. Equal numbers of surface control samples were collected from areas away from the structures. Metal concentrations were elevated in both the soil cores and surface samples collected from below the CCA-treated structures. Core samples showed elevated concentrations of metals at depths up to 20 cm. The arithmetic mean concentrations of arsenic, chromium, and copper in the 65 surface soil samples collected from below CCA-treated structures were 28.5 mg/kg, 31.1 mg/kg, and 37.2 mg/kg, respectively, whereas the mean concentrations of arsenic, chromium, and copper in the control samples were 1.34 mg/kg, 8.62 mg/kg, and 6.05 mg/kg, respectively. Arsenic concentrations exceeded Florida's risk-based soil cleanup target level (SCTL) for residential settings in all 65 surface soil samples. The industrial setting SCTL was exceeded in 62 of the 65 samples.     

Penetration of the Blood-Brain Barrier by Bacillus anthracis Requires the pXO1-Encoded BslA Protein

Anthrax is a zoonotic disease caused by the gram-positive spore-forming bacterium Bacillus anthracis. Human infection occurs after the ingestion, inhalation, or cutaneous inoculation of B. anthracis spores. The subsequent progression of the disease is largely mediated by two native virulence plasmids, pXO1 and pXO2, and is characterized by septicemia, toxemia, and meningitis. In order to produce meningitis, blood-borne bacteria must interact with and breach the blood-brain barrier (BBB) that is composed of a specialized layer of brain microvascular endothelial cells (BMEC). We have recently shown that B. anthracis Sterne is capable of penetrating the BBB in vitro and in vivo, establishing the classic signs of meningitis; however, the molecular mechanisms underlying the central nervous system (CNS) tropism are not known. Here, we show that attachment to and invasion of human BMEC by B. anthracis Sterne is mediated by the pXO1 plasmid and an encoded envelope factor, BslA. The results of studies using complementation analysis, recombinant BslA protein, and heterologous expression demonstrate that BslA is both necessary and sufficient to promote adherence to brain endothelium. Furthermore, mice injected with the BslA-deficient strain exhibited a significant decrease in the frequency of brain infection compared to mice injected with the parental strain. In addition, BslA contributed to BBB breakdown by disrupting tight junction protein ZO-1. Our results identify the pXO1-encoded BslA adhesin as a critical mediator of CNS entry and offer new insights into the pathogenesis of anthrax meningitis.Bacillus anthracis, the etiologic agent of anthrax, is a gram-positive spore-forming bacterium that is commonly found in soil (29). The bacterium can infect animals and humans by ingestion, inhalation, or cutaneous inoculation of B. anthracis spores (8). Spores are taken up by resident macrophages that migrate to the lymph nodes (15). Here, the spores germinate into vegetative bacteria, multiply, and then disseminate throughout the host, causing septicemia and toxemia (8). Systemic disease can be complicated by the onset of a fulminant and rapidly fatal hemorrhagic meningitis and meningoencephalitis (27). Anthrax meningitis is associated with a high mortality rate despite intensive antibiotic therapy (24). Biopsy studies after an outbreak of inhalational anthrax and experimental studies of inhalational infection in rhesus monkeys demonstrated the presence of bacilli in the central nervous system (CNS) and pathologies consistent with suppurative and hemorrhagic meningitis in the majority of cases (1, 12). The intentional release of B. anthracis spores (19) during the 2001 bioterrorism event resulted in a case of meningitis (19), necessitating a need for a better understanding of the pathogenesis of anthrax meningitis and CNS infection.To cause meningitis, blood-borne bacteria must interact with and breach the blood-brain barrier (BBB). The majority of the BBB is anatomically represented by the cerebral microvascular endothelium; brain microvascular endothelial cells (BMEC) are joined by tight junctions and display a paucity of pinocytosis, thereby effectively limiting the passage of substances and maintaining the CNS microenvironment (4, 5). Despite its highly restrictive nature, certain bacterial pathogens are still able to penetrate the BBB and gain entry into the CNS. The presence of bacilli in the brains of patients (1, 24) and in experimental models of anthrax infection (42, 44) suggests that vegetative B. anthracis cells are able to cross the BBB to initiate meningeal inflammation and the classic pathology associated with meningitis.B. anthracis harbors two large virulence plasmids, pXO1 and pXO2 (8), which are required for full virulence, as strains lacking these plasmids are attenuated in animal models of infection (29). B. anthracis Sterne (pXO1⁺ pXO2⁻) has been utilized as a vaccine strain (41) but is still widely used in both in vitro and in vivo studies of anthrax infection since it causes lethal disease in mouse models of infection (46). Despite the crucial roles of pXO1 and pXO2 in anthrax disease pathogenesis, very few plasmid-encoded factors have been characterized. The best described are the antiphagocytic polyglutamyl capsule, encoded by biosynthetic enzymes on pXO2, and the anthrax toxin complex comprised of protective antigen, lethal factor (LF), and edema factor (EF), encoded by pXO1 (8, 29). Sequence analysis of the pXO1 plasmid revealed that the majority of plasmid-encoded factors, ∼70%, were of unknown function (31). More recently, in silico analysis identified novel pXO1-encoded proteins with immunogenic potential and relevance for pathogenesis. These included factors with putative adherent and invasive properties (2). Interestingly, two of the immunoreactive proteins were predicted surface layer (S-layer) proteins (2), one of which, B. anthracis S-layer protein A (BslA, pXO1-90), has recently been described and shown to mediate adherence of the vegetative form to host cells (20).Using in vitro and in vivo model systems, we have recently shown that B. anthracis Sterne adheres to and invades brain endothelium (44). This interaction was partially dependent on the pXO1-encoded anthrax toxins; however, the molecular mechanisms that contribute to B. anthracis penetration of the BBB are currently unknown. In this study, we investigate the role of pXO1 in B. anthracis Sterne''s interaction with brain endothelium and identify the encoded BslA adhesin as a critical mediator for BBB attachment and penetration during the pathogenesis of anthrax meningitis.     

Neutrophil Gelatinase-Associated Lipocalin induces the expression of heme oxygenase-1 and superoxide dismutase <Subscript>1, 2</Subscript>

Lipocalin-2 (Lcn2, NGAL) is a member of the lipocalin super family with diverse function such as the induction of apoptosis, the suppression of bacterial growth, and modulation of inflammatory response. Much interest has recently been focused on the physiological/pathological role of the lipocalin-2 that is considered to be a novel protective factor against oxidative stress. However, its precise biological roles in this protection are not fully understood. In this report we intended to test the effect of lipocalin-2 on the expression of heme oxygenase _{(1, 2)} and superoxide dismutase _{(1, 2)} which are two strong antioxidants. NGAL was cloned to pcDNA3.1 plasmid by using genetic engineering method. The recombinant vector was transfected to CHO and HEK293T to establish stable cell expressing NGAL and the expression of HO-1, 2 and SOD_{1, 2} were compared with appropriate controls by RT-PCR and western blot. On the other hand, expression of NGAL was suppressed by siRNA transfection in order to study the effect of lipocalin-2 on mentioned genes/proteins. The results showed that the expression of HO-1 and SOD_{1, 2} enzymes were higher in cells expressing recombinant lipocalin-2 compared with the control cells. Although the expression of HO-1 was lower in NGAL silencing cells, the expression of SOD₁ and SOD₂ were higher. Our data suggest that NGAL is a potent inducer of HO-1 and somewhat SOD₁ and SOD₂ and it appears that part of antioxidant property of NGAL could be attributed to the induction of HO-1and SOD_{1, 2}.     

Identification of GABA A receptor modulators in Kadsura longipedunculata and assignment of absolute configurations by quantum-chemical ECD calculations

A petroleum ether extract of Kadsura longipedunculata enhanced the GABA-induced chloride current (I_GABA) by 122.5 ± 0.3% (n = 2) when tested at 100 μg/ml in Xenopuslaevis oocytes expressing GABA A receptors (α₁β₂γ_2S subtype) in two-microelectrode voltage clamp measurements. Thirteen compounds were subsequently identified by HPLC-based activity profiling as responsible for GABA A receptor activity and purified in preparative scale. 6-Cinnamoyl-6,7-dihydro-7-myrceneol and 5,6-dihydrocuparenic acid were thereby isolated for the first time. The determination of the absolute stereochemistry of these compounds was achieved by comparison of experimental and calculated ECD spectra. All but one of the 13 isolated compounds from K. longipedunculata potentiated I_GABA through GABA A receptors composed of α₁β₂γ_2S subunits in a concentration-dependent manner. Potencies ranged from 12.8 ± 3.1 to 135.6 ± 85.7 μM, and efficiencies ranged from 129.7 ± 36.8% to 885.8 ± 291.2%. The phytochemical profiles of petroleum ether extracts of Kadsura japonica fruits (114.1 ± 2.6% potentiation of I_GABA at 100 μg/ml, n = 2), and Schisandra chinensis fruits (inactive at 100 μg/ml) were compared by HPLC-PDA-ESIMS with that of K. longipedunculata.     

Mass and relative elution time profiling: two-dimensional analysis of sphingolipids in Alzheimer's disease brains

Current lipidomic profiling methods rely mainly on MS to identify unknown lipids within a complex sample. We describe a new approach, involving LC×MS/MS (liquid chromatography×tandem MS) analysis of sphingolipids based on both mass and hydrophobicity, and use this method to characterize the SM (sphingomyelin), ceramide and GalCer (galactosylceramide) content of hippocampus from AD (Alzheimer's disease) and control subjects. Using a mathematical relationship we exclude the influence of sphingolipid mass on retention time, and generate two-dimensional plots that facilitate accurate visualization and characterization of the different ceramide moieties within a given sphingolipid class, because related molecules align horizontally or vertically on the plots. Major brain GalCer species that differ in mass by only 0.04 Da were easily differentiated on the basis of their hydrophobicity. The importance of our method's capacity to define all of the major GalCer species in the brain samples is illustrated by the novel observation that the proportion of GalCer with hydroxylated fatty acids increased approximately 2-fold in the hippocampus of AD patients, compared with age- and gender-matched controls. This suggests activation of fatty acid hydroxylase in AD. Our method greatly improves the clarity of data obtained in a lipid profiling experiment and can be expanded to other lipid classes.     

Casein kinase I delta controls centrosome positioning during T cell activation

Although termed central body, the centrosome is located off-center in many polarized cells. T cell receptor (TCR) engagement by antigens induces a polarity switch in T cells. This leads to the recruitment of the centrosome to the immunological synapse (IS), a specialized cell-cell junction. Despite much recent progress, how TCR signaling triggers centrosome repositioning remains poorly understood. In this paper, we uncover a critical requirement for the centrosomal casein kinase I delta (CKIδ) in centrosome translocation to the IS. CKIδ binds and phosphorylates the microtubule plus-end-binding protein EB1. Moreover, a putative EB1-binding motif at the C terminus of CKIδ is required for centrosome translocation to the IS. We find that depletion of CKIδ in T lymphocytes and inhibition of CKI in epithelial cells reduce microtubule growth. Therefore, we propose that CKIδ-EB1 complexes contribute to the increase in microtubule growth speeds observed in polarized T cells, a mechanism that might serve to generate long-stable microtubules necessary for centrosome translocation.     

Understanding the Underlying Mechanism of HA-Subtyping in the Level of Physic-Chemical Characteristics of Protein

The evolution of the influenza A virus to increase its host range is a major concern worldwide. Molecular mechanisms of increasing host range are largely unknown. Influenza surface proteins play determining roles in reorganization of host-sialic acid receptors and host range. In an attempt to uncover the physic-chemical attributes which govern HA subtyping, we performed a large scale functional analysis of over 7000 sequences of 16 different HA subtypes. Large number (896) of physic-chemical protein characteristics were calculated for each HA sequence. Then, 10 different attribute weighting algorithms were used to find the key characteristics distinguishing HA subtypes. Furthermore, to discover machine leaning models which can predict HA subtypes, various Decision Tree, Support Vector Machine, Naïve Bayes, and Neural Network models were trained on calculated protein characteristics dataset as well as 10 trimmed datasets generated by attribute weighting algorithms. The prediction accuracies of the machine learning methods were evaluated by 10-fold cross validation. The results highlighted the frequency of Gln (selected by 80% of attribute weighting algorithms), percentage/frequency of Tyr, percentage of Cys, and frequencies of Try and Glu (selected by 70% of attribute weighting algorithms) as the key features that are associated with HA subtyping. Random Forest tree induction algorithm and RBF kernel function of SVM (scaled by grid search) showed high accuracy of 98% in clustering and predicting HA subtypes based on protein attributes. Decision tree models were successful in monitoring the short mutation/reassortment paths by which influenza virus can gain the key protein structure of another HA subtype and increase its host range in a short period of time with less energy consumption. Extracting and mining a large number of amino acid attributes of HA subtypes of influenza A virus through supervised algorithms represent a new avenue for understanding and predicting possible future structure of influenza pandemics.