Assessment of C-DBP and N-DBP formation potential and its reduction by MIEX® DOC and MIEX® GOLD resins using fluorescence spectroscopy and parallel factor analysis

This study investigated the applicability of parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices (EEM) spectra to assess the formation potentials (FP) of carbonaceous and nitrogenous disinfection byproducts (C-DBP and N-DBP) and the FP reduction by the magnetic ion exchange resins, MIEX® DOC and MIEX® GOLD. Two source waters of different nature - a surface water and a secondary treated wastewater effluent - were studied. The samples were analyzed for formation potentials of trihalomethanes (THM4), haloacetonitriles (HAN4), haloketones (HK2), and chloropicrin (CPN). A 4-component PARAFAC model was developed from 150 EEM samples generated from the raw source waters and their treatment with MIEX® resins. Components C1, C2, and C3 corresponded to humic-like dissolved organic matter (DOM) while C4 corresponded to protein-like DOM. Both MIEX® resins preferentially removed components C1, C2, and C3 over C4, indicating affinity with humic materials. MIEX® resins were shown to be more effective to treat surface water than secondary effluent, including effective removal of DBP precursors with extended bed volume treatment. Among all parameters investigated, THM4-FP strongly correlated with humic-like component C3, while HAN4-FP strongly correlated with protein-like component C4 (ρ > 0.89 and p < 0.01); CPN-FP and HK2-FP both correlated with anthropogenic DOM C2 (ρ > 0.89 and p < 0.01). Our results indicate that EEM-PARAFAC was valuable for assessing DBP formation potentials and removal of their precursors by MIEX® resins in different water sources.

Fluorescence spectroscopy for assessing trihalomethane precursors removal by MIEX resin

This study investigated the applicability of fluorescence excitation-emission matrix spectroscopy (EEMS) to assess total trihalomethane formation potentials (TTHMFPs) and the ability of magnetic ion exchange (MIEX^®) resin to reduce TTHMFP. We treated a surface water and secondary wastewater effluent with MIEX mimicking full-scale operation by repeatedly exposing the same resin batch to additional feed water, with batches ranging from 500 to 5,000 resin bed volumes. Results showed that MIEX was more effective at removing or reducing ultraviolet absorbance (UVA₂₅₄), dissolved organic carbon (DOC), and TTHMFP in surface water than in secondary effluent. The greater UVA₂₅₄, DOC and TTHMFP removal for surface waters was explained by the stronger affinity of MIEX for terrestrial dissolved organic matter (DOM) compared to microbial DOM. Fluorescence EEMS results showed that the ratio between terrestrial and microbial fluorescent signals of DOM was significantly greater in surface water than in secondary effluent. Fluorescence surrogate parameters were strongly correlated with TTHMFP, namely, fluorescence intensity of humic-like peak C (R² = 0.98, p < 0.01), protein-like peak T (R² = 0.96, p < 0.01), and fulvic-like peak A (R² = 0.87, p < 0.01). Correlations between fluorescence surrogate parameters and TTHMFP were substantially stronger than correlations between DOC and TTHMFP. Overall, the results indicate that fluorescent parameters extracted from EEMS data can be used as quick surrogate parameters to monitor TTHMFP for a diverse group of raw and MIEX-treated waters.

Biomarkers of NAFLD progression: a lipidomics approach to an epidemic

The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. Recognition and timely diagnosis of these different stages, particularly NASH, is important for both potential reversibility and limitation of complications. Liver biopsy remains the clinical standard for definitive diagnosis. Diagnostic tools minimizing the need for invasive procedures or that add information to histologic data are important in novel management strategies for the growing epidemic of NAFLD. We describe an "omics" approach to detecting a reproducible signature of lipid metabolites, aqueous intracellular metabolites, SNPs, and mRNA transcripts in a double-blinded study of patients with different stages of NAFLD that involves profiling liver biopsies, plasma, and urine samples. Using linear discriminant analysis, a panel of 20 plasma metabolites that includes glycerophospholipids, sphingolipids, sterols, and various aqueous small molecular weight components involved in cellular metabolic pathways, can be used to differentiate between NASH and steatosis. This identification of differential biomolecular signatures has the potential to improve clinical diagnosis and facilitate therapeutic intervention of NAFLD.

Regulation of phospholipase D activity and phosphatidic acid production after purinergic (P2Y6) receptor stimulation

Phosphatidic acid (PA) is a lipid second messenger located at the intersection of several lipid metabolism and cell signaling events including membrane trafficking, survival, and proliferation. Generation of signaling PA has long been primarily attributed to the activation of phospholipase D (PLD). PLD catalyzes the hydrolysis of phosphatidylcholine into PA. A variety of both receptor-tyrosine kinase and G-protein-coupled receptor stimulations have been shown to lead to PLD activation and PA generation. This study focuses on profiling the PA pool upon P2Y6 receptor signaling manipulation to determine the major PA producing enzymes. Here we show that PLD, although highly active, is not responsible for the majority of stable PA being produced upon UDP stimulation of the P2Y6 receptor and that PA levels are tightly regulated. By following PA flux in the cell we show that PLD is involved in an initial increase in PA upon receptor stimulation; however, when PLD is blocked, the cell compensates by increasing PA production from other sources. We further delineate the P2Y6 signaling pathway showing that phospholipase Cβ3 (PLCβ3), PLCδ1, DGKζ and PLD are all downstream of receptor activation. We also show that DGKζ is a novel negative regulator of PLD activity in this system that occurs through an inhibitory mechanism with PKCα. These results further define the downstream events resulting in PA production in the P2Y6 receptor signaling pathway.

Cobalt carbonyl complexes as probes for alkyne-tagged lipids

Monitoring lipid distribution and metabolism in cells and biological fluids poses many challenges because of the many molecular species and metabolic pathways that exist. This study describes the synthesis and study of molecules that contain an alkyne functional group as surrogates for natural lipids in cultured cells. Thus, hexadec-15-ynoic and hexadec-7-ynoic acids were readily incorporated into RAW 264.7 cells, principally as phosphocholine esters; the alkyne was used as a "tag" that could be transformed to a stable dicobalt-hexacarbonyl complex; and the complex could then be detected by HPLC/MS or HPLC/UV(349nm). The 349 nm absorbance of the cobalt complexes was used to provide qualitative and quantitative information about the distribution and cellular concentrations of the alkyne lipids. The alkyne group could also be used as an affinity tag for the lipids by a catch-and-release strategy on phosphine-coated silica beads. Lipid extracts were enriched in the tagged lipids in this way, making the approach of potential utility to study lipid transformations in cell culture. Both terminal alkynes and internal alkynes were used in this affinity "pull-down" strategy. This method facilitates measuring lipid species that might otherwise fall below limits of detection.

Capture and release of alkyne-derivatized glycerophospholipids using cobalt chemistry

Alkyne-modified phospholipids can be unambiguously identified and differentiated from native species in complex mixtures by formation of dicobalthexacarbonyl complexes. This reaction is specific for alkynes and is unaffected by other glycerophospholipid-related moieties. Enrichment of cells with alkyne-derivatized fatty acids or glycerophospholipids followed by solid-phase sequestration and release is a promising new method for unequivocally monitoring individual glycerophospholipids following incorporation into cells. This technique also facilitates lipidomic analysis of substrates and products.

Design and synthesis of isoform-selective phospholipase D (PLD) inhibitors. Part II. Identification of the 1,3,8-triazaspiro[4,5]decan-4-one privileged structure that engenders PLD2 selectivity

This Letter describes the synthesis and structure-activity relationships (SAR) of isoform-selective PLD inhibitors. By virtue of the installation of a 1,3,8-triazaspiro[4,5]decan-4-one privileged structure, PLD inhibitors with nanomolar potency and an unprecedented 40-fold selectivity for PLD2 over PLD1 were developed. Interestingly, SAR for this diverged from our earlier efforts, and dual PLD1/2 inhibitors were also discovered within this series.

Dramatic differences in the roles in lipid metabolism of two isoforms of diacylglycerol kinase

Lipid species changes for SV40-transformed fibroblasts from wild-type or from diacylglycerol kinase-epsilon (DGKepsilon) or diacylglycerol kinase-alpha (DGKalpha) knockout mice were determined for glycerophospholipids, polyphosphatidylinositides (GPInsP n ) and diacylglycerol (DAG) using direct infusion mass spectrometry. Dramatic differences in arachidonate (20:4 fatty acid)-containing lipids were observed for multiple classes of glycerophospholipids and polyphosphatidylinositides between wild-type and DGKepsilon knockout cells. However, no difference was observed in either the amount or the acyl chain composition of DAG between DGKepsilon knockout and wild-type cells, suggesting that DGKepsilon catalyzed the phosphorylation of a minor fraction of the DAG in these cells. The differences in arachidonate content between the two cell lines were greatest for the GPInsP n lipids and lowest for DAG. These findings indicate that DGKepsilon plays a significant role in determining the enrichment of GPInsP n with 20:4 and that there is a pathway for the selective translocation of arachidonoyl phosphatidic acid from the plasma membrane to the endoplasmic reticulum. In contrast, no substantial difference was observed in the acyl chain composition of any class of glycerophospholipid or diacylglycerol between lipid extracts from fibroblasts from wild-type mice or from DGKalpha knockout mice. However, the cells from the DGKalpha knockout mice had a higher concentration of DAG, consistent with the lack of downregulation of the major fraction of DAG by DGKalpha, in contrast with DGKepsilon that is primarily responsible for enrichment of GPInsP n with arachidonoyl acyl chains.

Immune-endocrine interactions of the hypothalamus-pituitary-thyroid axis: integration, communication and homeostasis

The immune and neuroendocrine systems are two essential physiological components of mammalian organisms. Although each is primarily committed to a set of tasks involved, on the one hand, in the protection from infection and disease, and on the other hand, in the regulation of metabolism and other physiological activities, there is also evidence indicating that active and dynamic collaborations exist between those systems in the execution of their designated functions. These interactions occur at many stages of embryonic and neonatal development, and they are a continual part of the normal homeostatic balance needed to maintain health. The present review discusses various historical and contemporary perspectives of immune-endocrine interactions involving the hypothalamus-pituitary-thyroid axis, and offers a hypothesis of how this aspect of the neuroendocrine system participates directly in the immune response to antigenic challenge, infection and disease.

Differential expression of CD43 isoforms on murine T cells and their relationship to acute intestinal graft versus host disease: studies using enhanced-green fluorescent protein transgenic mice

Three mAb (R2/60, S7 and 1B11) were used to study the expression of murine CD43 on peripheral T cells and intestinal intraepithelial lymphocytes (IEL) from normal mice, and from mice during acute graft versus host disease (GVHD). In the spleen, essentially all T cells expressed the R2/60 and S7 antigens, whereas the 1B11 antigen was expressed on about half of the CD8(+) cells and approximately 15% of CD4(+) T cells. Interestingly, a significant proportion of resting splenic B cells expressed the 1B11 and R2/60 antigens, but not the S7 antigen. The majority of IEL expressed R2/60 antigen; however, the S7 and 1B11 markers were differentially expressed on CD8alpha, CD8beta, TCRalphabeta and TCRgammadelta cells. Immunoprecipitation and Western blotting analyses identified characteristic 115 and 130 kDa reactive components from IEL lysates with mAb S7 and 1B11 respectively, and reactivity to both molecular entities by mAb R2/60. During acute intestinal GVHD induced by injecting CB6F(1) athymic nude mice with spleen cells from C57BL/6 enhanced-green fluorescent protein transgenic mice, 80-90% of donor T cells in the intestine epithelium expressed all CD43 isoforms; however, the level of expression of the 130 kDa CD43 antigen increased significantly and the level of the 115 kDa antigen decreased on GVHD donor T cells compared to cells at the time of transfer. Using EL4 cells, a similar shift in the expression of CD43 isoforms occurred experimentally following treatment with neuraminidase, suggesting that the type of CD43 isoform expressed on T cells is strongly influenced by conditions which affect membrane charge. The significance of these findings for intestinal immunopathology is discussed.

Distribution and abundance of herons, egrets, ibises and spoonbills in the Alligator Rivers Region, Northern Territory

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of Pacific herons (Ardea pacifica), pied herons (Ardea picata), cattle egrets (Ardeola ibis), great egrets (Egretta alba), little egrets (Egretta garzetta), intermediate egrets (Egretta intermedia), glossy ibis (Plegadis falcinellus), sacred ibis (Threskiornis aethiopica), straw-necked ibis (Threskiornis spinicollis) and royal spoonbills (Platalea regia) on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela. The aerial surveys indicated that the Magela floodplain was inhabited by few of these birds during the wet season (November-March), but that numbers then increased substantially in the dry season. The Nourlangie floodplain and Boggy Plain (a large backswamp of the South Alligator floodplain) showed similar patterns, but the numbers of birds tended to be lower. Birds were generally uncommon on the shallower East Alligator and Cooper floodplains, except for egrets in the wet season. Ground surveys suggested that the birds sought out the persistent swamps that characterise the Magela foodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities. On the basis of correction factors calculated from ground surveys, peak numbers on the five floodplains were roughly estimated to be about 4000 pacific herons, 50 000 pied herons, 300 000 egrets (primarily intermediate egrets), 60 000 glossy ibis, 16 000 sacred ibis, 80 000 straw-necked ibis and 35 000 royal spoonbills. Great-billed herons (Ardea sumatrana), white-faced herons (Ardea novaehollandiae), striated herons (Butorides striata), rufous night herons (Nycticorax caledonicus), black bitterns (Dupetor flavicollis) and yellow-billed spoonbills (Platalea flavipes) were recorded sporadically in low numbers. The Alligator Rivers region acted as a dry-season refuge for herons, egrets, ibises and spoonbills because of the unusually persistent fresh waters of the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain.

Distribution and abundance of grebes, pelicans, darters, cormorants, rails and terns in the Alligator Rivers Region, Northern Territory

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of Australian pelicans (Pelecanus conspicillatus), darters (Anhinga melanogaster), little pied cormorants (Phalacrocorax melanoleucos), and whiskered terns (Chlidonias hybrida) on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela plain. The aerial surveys indicated that the Magela floodplain was inhabited by few of these birds during the wet season (November-March), but that numbers then increased substantially in the dry season. The Nourlangie floodplain showed similar patterns, but the numbers of birds tended to be lower. Birds were generally uncommon on the shallower East Alligator and Cooper floodplains. Ground surveys suggested that the birds sought out the persistent swamps that characterise the Magela floodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities; on the basis of correction factors calculated from ground surveys, peak numbers on the five floodplains were roughly estimated to be about 2000 darters, 9000 little pied cormorants, 55 000 Australian pelicans and 50 000 whiskered terns. Little black cormorants (Phalacrocorax sulcirostrus) were sometimes abundant, but their sporadic occurrence prevented analysis of seasonal trends. Australasian grebes (Tachybaptus novaehollandiae), great cormorants (Phalacrocorax carbo), pied cormorants (Phalacrocorax varius), buff-banded rails (Rallus philippensis), Baillon's crakes (Porzana pusilla), white-browed crakes (Poliolimnas cinereus), purple swamphens (Porphyrio porphyrio), Eurasian coots (Fulica atra), silver gulls (Larus novaehollandiae), white-winged terns (Chlidonias leucoptera), gull-billed terns (Gelochelidon nilotica) and Caspian terns (Hydroprogne caspia) were recorded in low numbers. The Alligator Rivers region acted as an important dry season refuge because of the unusually persistent fresh waters of the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain.

Distribution and Abundance of Ducks in the Alligator Rivers Region, Northern Territory

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of wandering whistling-duck Dendrocygna arcuata, plumed whistling-duck D. eytoni, radjah shelduck Tadorna radjah, Pacific black duck Anas superciliosa, and grey teal A. gibberifrons on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal north of the Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela plain, to provide more detailed information. The Magela floodplain was inhabited by few ducks during the wet season (November to March), but numbers then increased to dramatic peaks in the late dry season. The Nourlangie floodplain and Boggy Plain (a large backswamp of the South Alligator floodplain) showed similar patterns, but the numbers of ducks were usually fewer. Ducks were uncommon on the shallower East Alligator and Cooper floodplains except for relatively brief periods in the wet season. The ground surveys suggested that ducks sought out the persistent swamps that characterise the Magela floodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities; on the basis of correction factors calculated from the ground surveys, peak numbers on the five floodplains were roughly estimated to be 400 000 wandering whistling-ducks, 70 000 plumed whistling-ducks, 20 000 radjah shelducks, 50 000 Pacific black ducks, and 50 000 grey teal. Pink-eared ducks Malacorhynchus membranaceus and hardhead Aythya australis were recorded sporadically in low numbers. The Alligator Rivers region acted as a dry season refuge for large concentrations of ducks because of the atypical persistence of freshwaters on the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain. The large aggregations appear to be unique in Australia.

N-delta-acetylornithine and S-methylcysteine in blood plasma

N-delta-Acetylornithine and S-methylcysteine have been identified as minor components of deproteinized blood plasma of human and bovine blood. Human blood plasma contains a variable amount of acetylornithine, averaging 1.1 +/- 0.4 mumol/l (range 0.8--0.2 mumol/l). Urine contains a very small amount of acetylornithine, approximately 1 nmol/mg creatinine (1 mumol/day). Human blood plasma contains 3.9 +/- 1.9 mumol/l (range 1.4--6.5 mumol/l) of S-methylcysteine. Urine contains approximately 5 nmol/mg creatinine; after acid hydrolysis the amount is increased to 20 nmol/mg creatinine.

The occurrence of cystinylglycine in blood plasma

Cystinylglycine has been identified as a minor ninhydrin-positive component of deproteinized blood plasma from human, bovine, rat and rabbit blood. The amount present in human blood plasma is approximately one-fifth of that of cystine and is not significantly correlated with age or with the cystine level.

Tissue free amino acid concentrations in perinatal rabbits

Free amino acids were measured in extracts from liver, kidney, and skeletal muscle (m. psoas major) of fetal, newborn, and adult rabbits. The total amount of free amino acids is at a higher level in fetal tissues than in adults; this difference is rather small in the liver, slightly larger in renal and very marked in muscle tissue. Perinatal changes of individual amino acid concentrations are different in each tissue studied. Many of such changes can be interpreted as a reflection of the metabolic sitation in each organ, e.g., the great need for essential amino acids during phases of very active protein synthesis. There were essentially no good correlations between developmental changes occurring in tissues and those in plasma.