Carbohydrate-controlled serine protease inhibitor (serpin) production in Bifidobacterium longum subsp. longum.

The Serine Protease Inhibitor (serpin) protein has been suggested to play a key role in the interaction of bifidobacteria with the host. By inhibiting intestinal serine proteases, it might allow bifidobacteria to reside in specific gut niches. In inflammatory diseases where serine proteases contribute to the innate defense mechanism of the host, serpin may dampen the damaging effects of inflammation. In view of the beneficial roles of this protein, it is important to understand how its production is regulated. Here we demonstrate that Bifidobacterium longum NCC 2705 serpin production is tightly regulated by carbohydrates. Galactose and fructose increase the production of this protein while glucose prevents it, suggesting the involvement of catabolite repression. We identified that di- and oligosaccharides containing galactose (GOS) and fructose (FOS) moieties, including the human milk oligosaccharide Lacto-N-tetraose (LNT), are able to activate serpin production. Moreover, we show that the carbohydrate mediated regulation is conserved within B. longum subsp. longum strains but not in other bifidobacterial taxons harboring the serpin coding gene, highlighting that the serpin regulation circuits are not only species- but also subspecies- specific. Our work demonstrates that environmental conditions can modulate expression of an important effector molecule of B. longum, having potential important implications for probiotic manufacturing and supporting the postulated role of serpin in the ability of bifidobacteria to colonize the intestinal tract.

Human biomonitoring of arsenic and antimony in case of an elevated geogenic exposure.

Part of the northern Palatinate region in Germany is characterized by elevated levels of arsenic and antimony in the soil due to the presence of ore sources and former mining activities. In a biomonitoring study, 218 residents were investigated for a putative increased intake of these elements. Seventy-six nonexposed subjects in a rural region in south lower Saxony were chosen as the reference group. Urine and scalp hair samples were obtained as surrogates to determine the internal exposures to arsenic and antimony. The analyses were performed using graphite furnace atomic absorption spectrometry except for arsenic in urine, which was determined by the hydride technique. This method does not detect organoarsenicals from seafood, which are not toxicologically relevant. In the northern Palatinate subjects, slightly elevated arsenic contents in urine and scalp hair (presumably not hazardous) could be correlated with an increased arsenic content in the soil. On the other hand, the results did not show a correlation between the antimony contents in the soil of the housing area and those in urine and hair. Except for antimony in scalp hair, age tended to be associated with internal exposures to arsenic and antimony in both study groups. Consumption of seafood had a slight impact on the level of urinary arsenic, which is indicative of the presence of low quantities of inorganic arsenicals and dimethylarsinic acid in seafood. The arsenic and antimony contents in scalp hair were positively correlated with the 24-hr arsenic excretion in urine. However, antimony in scalp hair was not correlated with seafood consumption as was arsenic in scalp hair and in urine. This indicated the existence of unidentified common pathways of exposure contributing to the alimentary body burden. Short time peaks in the 24-hr excretion of arsenic in urine, which could not be assigned to a high consumption of seafood, were detected for six study participants. This suggests that additional factors relevant in the exposure to arsenic are still unidentified.

Genotoxicity of polycyclic musk fragrances in the sister-chromatid exchange test.

The synthetic polycyclic musk fragrance compounds Galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclo-penta-(g)-2-++ +benzopyrane, Tonalide (7-acetyl-1,1,3,4,4,6-hexamerthyltetraline), Celestolide (4-acetyl-1,1-dimethyl-6-tert, butylindane), Phantolide (6-acetyl-1,1,2,3,3,5-hexamethylindane), Cashmeran (6,7-dihydro-1,1,2,3,3-pentamethyl-4-(5H) indanone) and Traseolide (5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane) are widely used as fragrance ingredients in perfumes, lotions and detergents; as food additives in cigarettes and fish baits. Several studies identified polycyclic musk fragrances in aquatic environment samples, human milk and human adipose tissue as highly lipophil with human lymphocytes.

Micronucleus formation in human lymphocytes and in the metabolically competent human hepatoma cell line Hep-G2: results with 15 naturally occurring substances.

To examine the concordance of two metabolizing systems for use in genotoxocity testing with the micronucleus test, 15 naturally occurring substances (arecoline, the plant extract aristolochic acid, beta-asarone, benzyl acetate, coumarin, emodine, isatidine dihydrate, monocrotaline, psoralen, reserpine, retrorsine, safrole, sanguinarine chloride, tannin and thiourea) were tested for their genotoxicity in the cytokinesis-block micronucleus test in vitro with human lymphocytes and in the presence and the absence of an exogenous metabolizing system from rat liver S9-mix and the metabolically competent human hepatoma cell line Hep-G2. Arecoline, the plant extract aristolochic acid, psoralen and tannin caused a significant increase in the number of micronuclei in human lymphocytes in the presence and the absence of an exogenous metabolising system from rat liver S9-mix and the metabolically competent human hepatoma cell line Hep-G2. A significant increase in the number of micronuclei with beta-asarone, coumarin, monocrotaline and retrorsine could be detected in the presence of S9-mix and the cell line Hep-G2. Benzyl acetate, emodine, isatidine dihydrate, reserpine, safrole, sanguinarine chloride and thiourea did not reveal any micronucleus inducing activity in either human lymphocytes or in Hep-G2. In addition to the other Hep-G2 results in the literature, this human hepatoma cell line could have a useful potential in the in vitro micronucleus test.

Studies on the influence of the copper content in the drinking water on the newborn copper burden and transaminases activity.

INTRODUCTION: Clinical parameters for the early diagnosis of a potential development of childhood cirrhosis are not available. A cross-section study was performed to investigate whether the serum copper content and the activities of the newborn's glutamic oxalacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) may be associated with the copper contents of the drinking water and/or the maternal serum and thus could serve as early indicator of an elevated health hazard. MATERIAL AND METHODS: The serum concentration of copper was analyzed in samples of 141 mother-newborn pairs. Additionally, in umbilical cord serum the activities of the transaminases GOT and GPT were determined. Low molecular bound or free copper was quantified in 30 randomly chosen serum filtrates. According to questionnaire data, in 62 of the 141 households the drinking water installations consisted of copper. In these cases, the element was analyzed in drinking water. RESULTS: The copper content of the drinking water was found ranging between 0.02 and 2.5 mg Cu/l (median 0.22 mg Cu/l), the maternal serum copper content ranged from 770-3720 micrograms Cu/l (median 2275 micrograms Cu/l), the neonatal serum from 220 to 1930 micrograms Cu/l (median 500 micrograms Cu/l), respectively. GOT (6-33 U/l); median 14 U/l) and GPT (3-21 U/l; median 6 U/l) activities could be judged as reference range data. In the statistical analysis, an association between the copper content of the drinking water and the maternal or neonatal serum copper content could not be found. Pearson regression analysis revealed slight, yet significant correlations of the neonatal GOT and GPT activities with the maternal serum copper content (GPT: r2 = 0.06; p < 0.05; GOT: r2 = 0.05; p < 0.05; each n = 139). In addition, the copper content of the mother's serum filtrates was correlated with the newborns' serum filtrates (Spearman: r = 0.61; p < 0.001; n = 30). CONCLUSIONS: The prenatal copper exposure of the infant could be mainly determined by low molecular or free serum maternal copper, which seems to be able to penetrate the placental barrier easily. The association between maternal serum copper content and neonatal transaminases activity can be judged as clinically not relevant and might be a physiologic response.