Abstract  The present study was conducted to follow up on apparent differences in growth, relative organ sizes, cellular stress and immune function in Atlantic salmon fed feed containing GM Bacillus thuringiensis maize compared with feed containing the non-modified parental maize line. Gene expression profiling on the distal intestinal segment and liver was performed by microarray, and selected genes were followed up by quantitative PCR (qPCR). In the liver, qPCR revealed some differentially regulated genes, including up-regulation of gelsolin precursor, down-regulation of ferritin heavy subunit and a tendency towards down-regulation of metallothionein (MT)-B. This, combined with the up-regulation of anti-apoptotic protein NR13 and similar tendencies for ferritin heavy chain and MT-A and -B in the distal intestine, suggests changes in cellular stress/antioxidant status. This corresponds well with and strengthens previous findings in these fish. To exclude possible confounding factors, the maize ingredients were analysed for mycotoxins and metabolites. The GM maize contained 90 μg/kg of deoxynivalenol (DON), while the non-GM maize was below the detection limit. Differences were also observed in the metabolite profiles of the two maize varieties, some of which seemed connected to the mycotoxin level. The effects on salmon observed in the present and previous studies correspond relatively well with the effects of DON as reported in the literature for other production animals, but knowledge regarding effects and harmful dose levels in fish is scarce. Thus, it is difficult to conclude whether the observed effects are caused by the DON level or by some other aspect of the GM maize ingredient.

Abstract  The chloride channel blockers SITS (4-acetamido-4'-isothiocyanostibene-2,2'-disulphonic acid) and DIDS (4,4'-diisothiocyanostilbene-2,2'-disulphonic acid) markedly suppressed progesterone production in the Rana temporaria and Xenopus laevis follicle-enclosed oocytes and oocyte maturation stimulated by the homologous pituitary suspension and hCG, respectively. Inhibition was dose-dependent and decreased with the increase of the hormone concentration. SITS did not affect progesterone production in the R. temporaria follicle-enclosed oocytes stimulated by dbcAMP. Substitution of sodium chloride for equimolar concentrations of sodium gluconate, methanesulfonate, glutamate, or formate significantly potentiated the gonadotropin-stimulated progesterone production and oocyte maturation in the both species. Possible involvement of chloride channels in progesterone production by the gonadotropin-stimulated amphibian follicle-enclosed oocytes is discussed. (C) 1997 Wiley-Liss, Inc.

Abstract  Gluconic acid is a multifunctional organic acid used as a bulk chemical in the food, feed, pharmaceutical, textile, metallurgy, detergent, paper, and construction industries. It is derived from glucose through a simple oxidation reaction catalyzed by glucose oxidase (EC 1.1.3.4.). Oxidation of the aldehyde group on C-1 of β-d-glucose to a carboxyl group results in the production of glucono-δ-lactone (C6H10O6) and hydrogen peroxide using molecular oxygen as the electron acceptor. Glucono-δ-lactone is further hydrolyzed to gluconic acid either spontaneously or by lactone-hydrolyzing enzyme. There are various approaches such as chemical, biochemical, and electrochemical available for its production, but microbial fermentation by Aspergillus niger using glucose oxidase is the most widely studied method. Microbial production of gluconic acid by bacteria, Gluconobacter, has also been demonstrated well. The enzyme involved in this process is glucose dehydrogenase. This chapter gives a review of microbial gluconic acid production; its recovery, properties, and applications; and the enzyme glucose oxidase.

Abstract  Daphnia are highly sensitive to sodium metabolism disruption caused by aquatic acidification and ionoregulatory toxicants, due to their finely balanced ion homeostasis. Nine different water chemistries of varying pH (4, 6 and 8) and calcium concentration (0, 0.5 and 1 mmol l(-1)) were used to delineate the mechanism of sodium influx in Daphnia magna. Lowering water pH severely inhibited sodium influx when calcium concentration was high, but transport kinetic analysis revealed a stimulated sodium influx capacity (J(max)) when calcium was absent. At low pH increasing water calcium levels decreased J(max) and raised K(m) (decreased sodium influx affinity), while at high pH the opposite pattern was observed (elevated J(max) and reduced K(m)). These effects on sodium influx were mirrored by changes in whole body sodium levels. Further examination of the effect of calcium on sodium influx showed a severe inhibition of sodium uptake by 100 micromol l(-1) calcium gluconate at both low (50 micromol l(-1)) and high (1000 micromol l(-1)) sodium concentrations. At high sodium concentrations, stimulated sodium influx was noted with elevated calcium levels. These results, in addition to data showing amiloride inhibition of sodium influx (K(i)=180 micromol l(-1)), suggest a mechanism of sodium influx in Daphnia magna that involves the electrogenic 2Na(+)/1H(+) exchanger.

Abstract  Environmental Effect of Photoprocessing Chemicals Vol I and II (557).

Abstract  Acute toxicity of four relatively new chelating agents and their equimolar manganese and cadmium complexes was studied. The chelating agents studied were gluconic acid (GA), beta-alaninediacetic acid (ADA), diethylenetriaminepentakismethylenephosphonic acid (DTPMP), and nitrilotriacetic acid (NTA). Three common bioassays, namely Daphnia magna, Raphidocelis subcapitata, and Photobacterium phosphoreum (Microtox bioassay) were applied. R. subcapitata proved the most sensitive to these compounds. With D. magna bioassay the LC(50) values were 600-900 mg/L with all other studied chelates and their Mn complexes, except Mn-GA, which yielded LC(50) value of 240 mg/L. The Cd-chelate complexes proved highly more toxic compared to Mn-chelate complexes or uncomplexed chelates exhibiting LC(50) values of 130-200 microg/L. However, Cd-DTPMP was an exception exhibiting LC(50) value of 2170 microg/L. That is to say, DTPMP proved the strongest chelating agent to reduce the Cd toxicity in the present study. The results from these bioassays were well in agreement to each other as well as with the results published elsewhere.

Abstract  Gluconate derivatives are presented as a category. Gluconic acid and its mineral salts freely dissociate to the gluconate anion and the respective cations. Glucono-delta-lactone (GDL), the 1,5-inner ester of gluconic acid, is formed from the free acid by the removal of water. On the basis of these spontaneous chemical rearrangements, glucono-delta-lactone, gluconic acid and its sodium, calcium and potassium salts can be considered as a category, with all members sharing the same representative moiety, the gluconate anion. Manufacturing and uses of the category members are also interlinked. The data summarized in this report are focused on the environmental and health effects from the gluconate anion and read-across to the lactone but do not deal with specific effects of the cations. Thus toxicological effects related to the cationic components are not part of the present report.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. Forty-seven chemicals having potential for preventing the attachment of zebra mussels Dreissena polymorpha were identified and tested. For each chemical, 15 zebra mussels (5-8-mm shell length) in each of two replicates and six treatments were exposed for 48 h followed by a 48-h postexposure period in untreated water. Eleven of the chemicals inhibited the reattachment of zebra mussels after the 48-h exposure; eight had EC50 values ranging from 0.4 to 5.4 mg, and three had EC50 values ranging from 19.4 to 29.0 mg/L. Based on an analysis of chemical cost, solubility in water, anticipated treatment concentrations, and potential hazards to humans or the environment, three of the most promising chemicals, all antioxidants, (butylated hydroxyanisole (BHA), tert-butylhydroquinone, and tannic acid) were tested on nontarget fish (bluegill, Lepomis macrochirus; channel catfish, Icalurus punctatus; and rainbow trout, Oncorhynchus mykiss). These chemicals were not selectively toxic