Polyamines stimulate the formation of mutagenic 1,N2-propanodeoxyguanosine adducts from acetaldehyde

Alcoholic beverage consumption is associated with an increased risk of upper gastrointestinal cancer. Acetaldehyde (AA), the first metabolite of ethanol, is a suspected human carcinogen, but the molecular mechanisms underlying AA carcinogenicity are unclear. In this work, we tested the hypothesis that polyamines could facilitate the formation of mutagenic α-methyl-γ-hydroxy-1,N²-propano-2′-deoxyguanosine (Cr-PdG) adducts from biologically relevant AA concentrations. We found that Cr-PdG adducts could be formed by reacting deoxyguanosine with μM concentrations of AA in the presence of spermidine, but not with either AA or spermidine alone. The identities of the Cr-PdG adducts were confirmed by both liquid and gas chromatography-mass spectrometry. Using a novel isotope-dilution liquid chromatography-mass spectrometry assay, we found that in the presence of 5 mM spermidine, AA concentrations of 100 μM and above resulted in the formation of Cr-PdG in genomic DNA. These AA levels are within the range that occurs in human saliva after alcoholic beverage consumption. We also showed that spermidine directly reacts with AA to generate crotonaldehyde (CrA), most likely via an enamine aldol condensation mechanism. We propose that AA derived from ethanol metabolism is converted to CrA by polyamines in dividing cells, forming Cr-PdG adducts, which may be responsible for the carcinogenicity of alcoholic beverage consumption.     

Mode of Action of Lomofungin

Lomofungin inhibited the growth of some yeasts and mycelial fungi at concentrations between 5 and 10 μg/ml. At such concentrations, there was no decrease in endogenous and exogenous oxygen consumption, and even 50 μg of antibiotic per ml caused only slight decreases. The permeation of the cell membrane was changed so that leakage of ninhydrin-positive substances was reduced, and the uptake of ¹⁴C-labeled glucose, amino acids, uracil, and thymidine was decreased at concentrations as low as 4 μg/ml. Protein synthesis in whole cells of Saccharomyces cerevisiae was reduced 35% at 10 μg/ml. However, the antibiotic did not reduce the incorporation of phenylalanine-U-¹⁴C into polypeptides with cell-free systems of Rhizoctonia solani and S. cerevisiae. The synthesis of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) was inhibited even at concentrations of lomofungin of 4 μg/ml. Since RNA synthesis was inhibited at lower concentrations and earlier than DNA synthesis, the primary site of action of the antibiotic appears to be the synthesis of RNA.     

Mode of Action of Lomofungin

Lomofungin inhibited the growth of some yeasts and mycelial fungi at concentrations between 5 and 10 μg/ml. At such concentrations, there was no decrease in endogenous and exogenous oxygen consumption, and even 50 μg of antibiotic per ml caused only slight decreases. The permeation of the cell membrane was changed so that leakage of ninhydrin-positive substances was reduced, and the uptake of ¹⁴C-labeled glucose, amino acids, uracil, and thymidine was decreased at concentrations as low as 4 μg/ml. Protein synthesis in whole cells of Saccharomyces cerevisiae was reduced 35% at 10 μg/ml. However, the antibiotic did not reduce the incorporation of phenylalanine-U-¹⁴C into polypeptides with cell-free systems of Rhizoctonia solani and S. cerevisiae. The synthesis of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) was inhibited even at concentrations of lomofungin of 4 μg/ml. Since RNA synthesis was inhibited at lower concentrations and earlier than DNA synthesis, the primary site of action of the antibiotic appears to be the synthesis of RNA.     

Effects of Condensed Tannins on Endoglucanase Activity and Filter Paper Digestion by Fibrobacter succinogenes S85

The effect of condensed tannins from birdsfoot trefoil (Lotus corniculatus L.) on the cellulolytic rumen bacterium Fibrobacter succinogenes S85 was examined. Condensed tannins inhibited endoglucanase activity in the extracellular culture fluid, at concentrations as low as 25 μg ml^-1. In contrast, cell-associated endoglucanase activity increased in concentrations of condensed tannins between 100 and 300 μg ml^-1. Inhibition of endoglucanase activity in both the extracellular and the cell-associated fractions was virtually complete at 400 μg of condensed tannins ml^-1. Despite the sharp decline in extracellular endoglucanase activity with increasing concentrations of condensed tannins, filter paper digestion declined only moderately between 0 and 200 μg of condensed tannins ml^-1. However, at 300 μg ml^-1, filter paper digestion was dramatically reduced and at 400 μg ml^-1, almost no filter paper was digested. F. succinogenes S85 was seen to form digestive grooves on the surface of cellulose, and at 200 μg ml^-1, digestive pits were formed which penetrated into the interior of cellulose fibers. Cells grown with condensed tannins (100 to 300 μg ml^-1) possessed large amounts of surface material, and although this material may have been capsular carbohydrate, its osmiophilic nature suggested that it had arisen from the formation of tannin-protein complexes on the cell surface. The presence of electron-dense extracellular material suggested that similar complexes were formed with extracellular protein.     

Abscisic Acid Metabolism in Water-stressed Bean Leaves

Phaseic acid (PA) and dihydrophaseic acid (DPA) are the major metabolites observed when (S)-2-¹⁴C-abscisic acid (ABA) is fed to 14-day excised primary bean leaves (Phaseolus vulgaris L. cv. Red Kidney). The distribution of ¹⁴C in leaves which were wilted after feeding ABA appears to be the same as that observed in unwilted leaves. A reduction in the relative specific radioactivities of the two metabolites after wilting, compared with the specific radioactivities measured in unwilted plants, indicated that these metabolites continue to be formed endogenously after wilting. Estimates of the endogenous ABA levels showed that they rose from 0.04 μg to approximately 0.5 μg/g fresh weight within 4 hours after the beginning of a 10% wilt and remained at that level during a subsequent 20 hours of wilt. In unwilted leaves, the levels of PA and DPA were 5 times and 20 times higher than that of ABA, respectively. Both PA and DPA levels rose throughout the wilt period. PA rose from 0.20 μg to 1.0 μg and DPA from 0.8 μg to over 3 μg/g fresh weight. From these data, we calculated the rate of ABA synthesis to be at least 0.15 μg/hr.g fresh weight during this period. We have interpreted these results to mean that in wilted leaves an elevated level of ABA is maintained because the rate of synthesis and metabolism are both elevated and approximately equal.     

Glucose metabolism in the superovulated rat ovary in vitro. Effects of luteinizing hormone and the role of glucose metabolism in steroidogenesis

1. Superovulated rat ovary slices from rats treated with 20μg. of luteininzing hormone/100g. body wt. 2hr. before death and from control animals have been incubated in vitro. Output of Δ⁴-3-oxo steroids (0·2μmole/g. wet wt./hr. in control tissue) was linear for 4hr., and was increased by approx. 70% in slices from luteinizing hormone-treated rats. Rate of oxygen consumption (90·0±4·6μmoles/g. wet wt./hr.) was linear for 3hr. and unaltered by luteinizing hormone treatment or addition of glucose (1mg./ml.) to the medium. 2. In slices from control animals, steady-state rate of glucose uptake was 78·0±2·9μg. atoms of carbon/g. wet wt./hr.; steady-state rates of lactate output, pyruvate output and incorporation of [U-¹⁴C]-glucose carbon atoms into carbon dioxide and total lipid extract were 60·7±0·9, 2·4±0·1, 18·0±1·1 and 0·7±0·1μg. atom of carbon/g. wet wt./hr. and accounted for 104·5±1·9% of the glucose uptake. In slices from luteinizing hormone-treated rats, glucose uptake and outputs of lactate, pyruvate and [¹⁴C]carbon dioxide were increased by approx. 25%, and 108·4±3·2% of the glucose uptake could be accounted for. 3. The total lipid extract was separated by thin-layer chromatography and saponification. Of the ¹⁴C incorporated into this fraction during incubation with [U-¹⁴C]glucose 97% was found in the fractions containing glyceride glycerol and less than 3% in the fractions containing sterols, steroids or fatty acids. Appreciable quantities of ¹⁴C were incorporated into these lipid fractions from [1-¹⁴C]acetate. 4. From a consideration of the tissue glycogen content, the specific activities of [¹⁴C]lactate and glucose 6-phosphate (C-1) derived from [1-¹⁴C]-, [6-¹⁴C]- and [U-¹⁴C]-glucose, and the ratio of [¹⁴C]carbon dioxide yields from [1-¹⁴C]glucose and [6-¹⁴C]glucose, it was concluded that there was no appreciable glycogenolysis or flow through the pentose phosphate cycle. 5. In ovary slices from both control and luteinizing hormone-treated animals, glucose in vitro raised the incorporation rate of ¹⁴C from [1-¹⁴C]acetate into sterols and steroids. Luteinizing hormone in vivo stimulated the incorporation rate in vitro but only in the presence of glucose. 6. In slices incubated in medium containing [³H]water, [¹⁴C]sorbitol and glucose (1mg./ml.), the total water space (865±7·1μl./g.) and the extracellular water space (581±22μl./g.) were unchanged by luteinizing hormone treatment in vivo but the glucose space was raised from 540±23·6μl./g. to 639±31·3μl./g. 7. Luteinizing hormone treatment was found to lower the tissue concentration of the hexose monophosphates and to increase the total activity of hexokinase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and possibly of phosphofructokinase. 8. The kinetic properties of a partially purified preparation of phosphofructokinase were found to be qualitatively similar to those from other mammalian tissues. 9. The results are discussed with reference to both the role of glucose metabolism in steroidogenesis and the mechanism by which luteinizing hormone increases the rate of glucose uptake.     

Estimation of the Yield Coefficient of Pseudomonas sp. Strain DP-4 with a Low Substrate (2,4-Dichlorophenol [DCP]) Concentration in a Mineral Medium from Which Uncharacterized Organic Compounds Were Eliminated by a Non-DCP-Degrading Organism

The yield coefficient (YC) of Pseudomonas sp. strain DP-4, a 2,4-dichlorophenol (DCP)-degrading organism, was estimated from the number of CFU produced at the expense of 1 unit amount of DCP at low concentrations. At a low concentration of DCP, the YC can be overestimated in pure culture, because DP-4 assimilated not only DCP but also uncharacterized organic compounds contaminating a mineral salt medium. The concentration of these uncharacterized organic compounds was nutritionally equivalent to 0.7 μg of DCP-C ml⁻¹. A mixed culture with non-DCP-degrading organisms resulted in elimination of ca. 99.9% of the uncharacterized organic compounds, and then DP-4 assimilated only DCP as a substrate. In a mixed culture, DP-4 degraded an initial concentration of 0.1 to 10 μg of C ml of DCP⁻¹ and the number of CFU of DP-4 increased. In the mixed culture, DCP at an initial concentration of 0.07 μg of C ml⁻¹ was degraded. However, the number of CFU of DP-4 did not increase. DCP at an extremely low initial concentration of 0.01 μg of C ml⁻¹ was not degraded in mixed culture even by a high density, 10⁵ CFU ml⁻¹, of DP-4. When glucose was added to this mixed culture to a final concentration of 1 μg of C ml⁻¹, the initial concentration of 0.01 μg of C ml of DCP⁻¹ was degraded. These results suggested that DP-4 required cosubstrates to degrade DCP at an extremely low initial concentration of 0.01 μg of C ml⁻¹. The YCs of DP-4 at the expense of DCP alone decreased discontinuously with the decrease of the initial concentration of DCP, i.e., 1.5, 0.19, or 0 CFU per pg of DCP-C when 0.7 to 10, 0.1 to 0.5, or 0.07 μg of C ml of DCP⁻¹ was degraded, respectively. In this study, we developed a new method to eliminate uncharacterized organic compounds, and we estimated the YC of DP-4 at the expense of DCP as a sole source of carbon.     

Fecal Calprotectin Concentrations in Healthy Children Aged 1-18 Months

Objective

Fecal calprotectin (FC) is an established biomarker of gut inflammation. The aim of this study was to evaluate FC concentrations in healthy children between 1 and 18 months of age.

Methods

Healthy children aged 1-18 months were enrolled in this study at the Department of Children''s Health Care in Shanghai, China. Children’s stool samples were collected and analyzed, and FC concentration was determined using a commercially available enzyme-linked immunosorbent assay (ELISA). The children''s weights and lengths were measured. Parents were asked to complete a brief questionnaire regarding several clinical and sociodemographic factors.

Results

The FC concentrations were unevenly distributed; the median FC concentration was 174.3 μg/g (range: 6.0-1097.7 μg/g) or 2.241 log10 μg/g (range: 0.775-3.041 log10 μg/g) for all 288 children. The children were divided into several age groups: 1-3 months, 3-6 months, 6-9 months, 9-12 months and 12-18 months. The median FC concentrations for these age groups were 375.2 μg/g (2.574 log10 μg/g), 217.9 μg/g (2.338 log10 μg/g), 127.7 μg/g (2.106 log10 μg/g), 96.1 μg/g (1.983 log10 μg/g) and 104.2 μg/g (2.016 log10 μg/g), respectively. A significant correlation between age and FC concentration was found (r=-0.490, p<0.001). A simple correlation analysis of weight-for-length Z-scores or weight-for-age Z-scores vs. FC concentrations showed that these variables were negatively correlated (Spearman’s rho=-0.287, p<0.001; Spearman’s rho=-0.243, p<0.001, respectively).

Conclusions

The FC levels of children aged 1-18 months exhibit a downward trend with increasing age and are greater than the normal levels observed in healthy adults. In healthy children aged <6 months, FC levels are high. In children aged 6-18 months, FC concentrations are relatively low but are still higher than those of children aged >4 years.     

Fecal Calprotectin in Healthy Children Aged 1-4 Years

Objective

Calprotectin has been well emulated recently in adults as well as in children. The aim of this study was to assess fecal calprotectin concentrations in healthy children aged from 1 to 4 years.

Methods

Volunteers were enlisted from 3 nurseries. A brief questionnaire was used to ensure these children meet the inclusion criteria, and some clinical and sociodemographic factors were collected. Anthro software (version 3.1) was used to calculated Length-for-age Z-scores (LAZ), weight-for-age Z-scores (WAZ), and weight-for-length Z-scores (WLZ) respectively. Fecal calprotectin was detected by a commercially available ELISA.

Results

In total 274 children were recruited, with age ranging from 1 to 4 years old. The median FC concentration was 83.19 μg/g [range 4.58 to 702.50 μg/g, interquartile range (IQR) 14.69–419.45 μg/g] or 1.92 log10 μg/g (range 0.66 log10 to 2.85 log10 μg/g, IQR 1.17 log10-2.62 log10 μg/g). All of the children were divided into three groups, 1–2 years (12–24 months), 2–3 years (24–36 months), 3–4 years (36–48 months), with median FC concentrations 96.14 μg/g (1.98 log10 μg/g), 81.48 μg/g (1.91 log10 μg/g), 65.36 μg/g (1.82 log10 μg/g), respectively. There was similar FC level between boys and girls. FC concentrations showed a downward trend by the growing age groups. A statistic difference was found in FC concentrations among groups 1–2 years, 2–3 years and 3–4 years (P = 0.016). In inter-groups comparison, a significant difference was found between children aged 1–2 years and children aged 3–4 years (P = 0.007). A negative correlation trend was found between age and FC concentration (Spearman''s rho = -0.167, P = 0.005) in all the participants. A simple correlation was performed among WLZ, WAZ, birth weight, or birth length with FC, and there was no correlation being observed.

Conclusion

Children aged from 1 to 4 years old have lower FC concentrations compared with healthy infants (<1years), and higher FC concentrations when comparing with children older than 4 years and adults.     

A Novel Europium Chelate Coated Nanosphere for Time-Resolved Fluorescence Immunoassay

A novel europium ligand 2, 2’, 2’’, 2’’’-(4, 7-diphenyl-1, 10-phenanthroline-2, 9-diyl) bis (methylene) bis (azanetriyl) tetra acetic acid (BC-EDTA) was synthesized and characterized. It shows an emission spectrum peak at 610 nm when it is excited at 360 nm, with a large Stock shift (250 nm). It is covalently coated on the surface of a bare silica nanosphere containi free amino groups, using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-Hydroxysuccinimide. We also observed an interesting phenomenon that when BC-EDTA is labeled with a silica nanosphere, the chelate shows different excitation spectrum peaks of about 295 nm. We speculate that the carboxyl has a significant influence on its excitation spectrum. The BC-EDTA/Eu³⁺coated nanosphere could be used as a fluorescent probe for time-resolved fluorescence immunoassay. We labeled the antibody with the fluorescent nanosphere to develop a nanosphere based hepatitis B surface antigen as a time-resolved fluorescence immunoassay reagent, which is very easy to operate and eliminates potential contamination of Eu³⁺ contained in the environment. The analytical and functional sensitivities are 0.0037 μg/L and 0.08 μg/L (S/N≥2.0) respectively. The detection range is 0.08-166.67 μg/L, which is much wider than that of ELISA (0.2-5μg/L). It is comparable to the commercial dissociation-enhanced lanthanide fluoro-immunoassay system (DELFIA) reagents (0.2-145μg/L). We propose that it can fulfill clinical applications.     

Interaction of antibody-bearing small unilamellar liposomes with antigencoated cells. The effect of antibody and antigen concentration on the liposomal and cell surface respectively

Human blood lymphocytes were coated with increasing amounts of human kappa chain (2–85μg/10⁷ cells) through the linking reagent CrCl₃. These cells were then exposed to small unilamellar liposomes composed of egg phosphatidylcholine, cholesterol and phosphatidic acid (molar proportions 7:7:1) containing carboxyfluorescein and/or ¹¹¹In-labelled bleomycin and bearing ¹³¹I-labelled affinity chromatography-purified or non-purified anti-(kappa-chain) immunoglobulin G (IgG) [see the preceding paper, Gregoriadis, Meehan & Mah (1981) Biochem. J. 200, 203–210]. In some experiments liposomes contained [¹⁴C]phosphatidylcholine. (1) Lymphocytes (10⁷) coated with 2–85μg of kappa chain and exposed to liposomes devoid of IgG or bearing non-purified anti-(kappa chain) IgG bound only a small proportion of the liposomal markers. Even with liposomes bearing the purified anti-(kappa chain) IgG, uptake of the labels improved only slightly for cells coated with up to 10μg of kappa chain. However, with higher concentrations of the antigen on the cell surface, binding was improved considerably to reach values of 31% (¹¹¹In-labelled bleomycin) and 43% (¹³¹I-labelled IgG) of added liposomes for cells coated with 85μg of kappa chain. (2) Lymphocytes coated with kappa chain were exposed to liposomes bearing increasing amounts (0–180μg/0.9mg of egg phosphatidylcholine) of purified anti-(kappa chain) IgG. It was found that under the present conditions, binding of all three markers (¹¹¹In-labelled bleomycin, ¹³¹I-labelled IgG and [¹⁴C]phosphatidylcholine) was directly proportional to the concentration of IgG on the liposomal surface. However, uptake values remained unchanged above 90μg of IgG. (3) Antibody-mediated uptake of liposomes by cells coated with the corresponding antigen without loss of their metabolic activities may provide a method of efficient targeting.     

A New Sensitive Bioassay for Determination of Microbially Available Phosphorus in Water

The content of assimilable organic carbon has been proposed to control the growth of microbes in drinking water. However, recent results have shown that there are regions where it is predominantly phosphorus which determines the extent of microbial growth in drinking waters. Even a very low concentration of phosphorus (below 1 μg of P liter⁻¹) can promote extensive microbial growth. We present here a new sensitive method to determine microbially available phosphorus concentrations in water down to 0.08 μg of P liter⁻¹. The method is a bioassay in which the analysis of phosphorus in a water sample is based on maximum growth of Pseudomonas fluorescens P17 when the energy supply and inorganic nutrients, with the exception of phosphorus, do not limit bacterial growth. Maximum growth (CFU) in the water sample is related to the concentration of phosphorus with the factor 373,200 ± 9,400 CFU/μg of PO₄-P. A linear relationship was found between cell growth and phosphorus concentration between 0.05 to 10 μg of PO₄-P liter⁻¹. The content of microbially available phosphorus in Finnish drinking waters varied from 0.1 to 10.2 μg of P liter⁻¹ (median, 0.60 μg of P liter⁻¹).     

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp.

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [{"type":"entrez-nucleotide","attrs":{"text":"KF611679","term_id":"560187972","term_text":"KF611679"}}KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.     

New Anti-Inflammatory Metabolites by Microbial Transformation of Medrysone

Microbial transformation of the anti-inflammatory steroid medrysone (1) was carried out for the first time with the filamentous fungi Cunninghamella blakesleeana (ATCC 8688a), Neurospora crassa (ATCC 18419), and Rhizopus stolonifer (TSY 0471). The objective was to evaluate the anti-inflammatory potential of the substrate (1) and its metabolites. This yielded seven new metabolites, 14α-hydroxy-6α-methylpregn-4-ene-3,11,20-trione (2), 6β-hydroxy-6α-methylpregn-4-ene-3,11,20-trione (3), 15β-hydroxy-6α-methylpregn-4-ene-3,11,20-trione (4), 6β,17α-dihydroxy-6α-methylpregn-4-ene-3,11,20-trione (5), 6β,20S-dihydroxy-6α-methylpregn-4-ene-3,11-dione (6), 11β,16β-dihydroxy-6α-methylpregn-4-ene-3,11-dione (7), and 15β,20R-dihydroxy-6α-methylpregn-4-ene-3,11-dione (8). Single-crystal X-ray diffraction technique unambiguously established the structures of the metabolites 2, 4, 6, and 8. Fungal transformation of 1 yielded oxidation at the C-6β, -11β, -14α, -15β, -16β positions. Various cellular anti-inflammatory assays, including inhibition of phagocyte oxidative burst, T-cell proliferation, and cytokine were performed. Among all the tested compounds, metabolite 6 (IC₅₀ = 30.3 μg/mL) moderately inhibited the reactive oxygen species (ROS) produced from zymosan-induced human whole blood cells. Compounds 1, 4, 5, 7, and 8 strongly inhibited the proliferation of T-cells with IC₅₀ values between <0.2–10.4 μg/mL. Compound 7 was found to be the most potent inhibitor (IC₅₀ < 0.2 μg/mL), whereas compounds 2, 3, and 6 showed moderate levels of inhibition (IC₅₀ = 14.6–20.0 μg/mL). Compounds 1, and 7 also inhibited the production of pro-inflammatory cytokine TNF-α. All these compounds were found to be non-toxic to 3T3 cells (mouse fibroblast), and also showed no activity when tested against HeLa (human epithelial carcinoma), or against PC3 (prostate cancer) cancer cell lines.     

Modeling Yeast Spoilage in Cold-Filled Ready-To-Drink Beverages with Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Candida lipolytica

Mathematical models were developed to predict the probability of yeast spoilage of cold-filled ready-to-drink beverages as a function of beverage formulation. A Box-Behnken experimental design included five variables, each at three levels: pH (2.8, 3.3, and 3.8), titratable acidity (0.20, 0.40, and 0.60%), sugar content (8.0, 12.0, and 16.0 °Brix), sodium benzoate concentration (100, 225, and 350 ppm), and potassium sorbate concentration (100, 225, and 350 ppm). Duplicate samples were inoculated with a yeast cocktail (100 μl/50 ml) consisting of equal proportions of Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Candida lipolytica (~5.0 × 10⁴ CFU/ml each). The inoculated samples were plated on malt extract agar after 0, 1, 2, 4, 6, and 8 weeks. Logistic regression was used to create the predictive models. The pH and sodium benzoate and potassium sorbate concentrations were found to be significant factors controlling the probability of yeast growth. Interaction terms for pH and each preservative were also significant in the predictive model. Neither the titratable acidity nor the sugar content of the model beverages was a significant predictor of yeast growth in the ranges tested.     

Comparative efficacy of long-acting bronchodilators for COPD - a network meta-analysis

Background

Clinicians are faced with an increasingly difficult choice regarding the optimal bronchodilator for patients with chronic obstructive pulmonary disease (COPD) given the number of new treatments. The objective of this study is to evaluate the comparative efficacy of indacaterol 75/150/300 μg once daily (OD), glycopyrronium bromide 50 μg OD, tiotropium bromide 18 μg/5 μg OD, salmeterol 50 μg twice daily (BID), formoterol 12 μg BID, and placebo for moderate to severe COPD.

Methods

Forty randomized controlled trials were combined in a Bayesian network meta-analysis. Outcomes of interest were trough and post-dose forced expiratory volume in 1 second (FEV₁), St. George’s Respiratory Questionnaire (SGRQ) score and responders (≥4 points), and Transition Dyspnea Index (TDI) score and responders (≥1 point) at 6 months.

Results

Indacaterol was associated with a higher trough FEV₁ than other active treatments (difference for indacaterol 150 μg and 300 μg versus placebo: 152 mL (95% credible interval (CrI): 126, 179); 160 mL (95% CrI: 133, 187)) and the greatest improvement in SGRQ score (difference for indacaterol 150 μg and 300 μg versus placebo: -3.9 (95% CrI -5.2, -2.6); -3.6 (95% CrI -4.8, -2.3)). Glycopyrronium and tiotropium 18 μg resulted in the next best estimates for both outcomes with minor differences (difference for glycopyrronium versus tiotropium for trough FEV₁ and SGRQ: 18 mL (95% CrI: -16, 51); -0.55 (95% CrI: -2.04, 0.92).

Conclusion

In terms of trough FEV₁ and SGRQ score indacaterol, glycopyrronium, and tiotropium are expected to be the most effective bronchodilators.     

Accumulation,Allocation, and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soil-Brassica chinensis System

Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs) in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi’an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA), rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 μg/kg d.w., with an average of 41 μg/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1×10⁻⁶). The concentration of total PAHs was (1052±73) μg/kg d.w. in vegetation (mean±standard error). The cancer risks posed by ingestion of vegetation ranged from 2×10⁻⁵ to 2×10⁻⁴ with an average of 1.66×10⁻⁴, which was higher than international excess lifetime risk limits for carcinogens (1×10⁻⁴). The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil) increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation.     

Zooplankton Growth,Respiration and Grazing on the Australian Margins of the Tropical Indian and Pacific Oceans

The specific activity of aminoacyl-tRNA synthetases (spAARS), an index of growth rate, and of the electron transport system (spETS), an index of respiration, was measured in three size fractions (73–150 μm, >150 μm and >350 μm) of zooplankton during five cruises to tropical coastal waters of the Kimberley coast (North West Australia) and four cruises to waters of the Great Barrier Reef (GBR; North East Australia). The N-specific biomass of plankton was 3–4-fold higher in the Kimberley than on the GBR in all 3 size classes: Kimberley 1.27, 3.63, 1.94 mg m^-3; GBR 0.36, 0.88 and 0.58 mg m^-3 in the 73–150 μm, >150 μm and >350 μm size classes, respectively. Similarly, spAARS activity in the Kimberley was greater than that of the GBR: 88.4, 132.2, and 147.6 nmol PPi hr^-1 mg protein ^-1 in the Kimberley compared with 71.7, 82.0 and 83.8 nmol PPi hr^-1 mg protein ^-1 in the GBR, for the 73–150 μm, >150 μm and >350 μm size classes, respectively. Specific ETS activity showed similar differences in scale between the two coasts: 184.6, 148.8 and 92.2 μL O₂ hr^-1 mg protein^-1 in the Kimberley, against 86.5, 88.3 and 71.3 μL O₂ hr^-1 mg protein^-1 in the GBR. On the basis of these measurements, we calculated that >150 μm zooplankton grazing accounted for 7% of primary production in the Kimberley and 8% in GBR waters. Area-specific respiration by >73 μm zooplankton was 7-fold higher in the Kimberley than on the GBR and production by >150 μm zooplankton was of the order of 278 mg C m^-2 d^-1 in the Kimberley and 42 mg C m^-2 d^-1 on the GBR. We hypothesize that the much stronger physical forcing on the North West shelf is the principal driver of higher rates in the west than in the east of the continent.