Ochratoxin A occurrence in slaughter-pigs in Sweden and its use as a tool for feed screening programs.

The occurrence of ochratoxin A in pig blood can be used as a measure of ochratoxin A contamination of the feed. A method for ochratoxin A analysis in pig blood, suitable for screening programs, is presented. The relationship between ochratoxin A contents in the blood of pigs and the feed given is investigated with feeding experiments.

Human exposure to ochratoxin A in areas of Yugoslavia with endemic nephropathy.

Ochratoxin A is a mycotoxin with pronounced nephrotoxic potency in all species of single-stomach animals studied; it is a major disease determinant of porcine nephropathy and a disease occurring endemically in several countries. This disease is comparable with Balkan (endemic) nephropathy, suggesting a common causal relationship. Ochratoxin A has been found in foodstuffs in many countries, but the highest frequency of ochratoxin A contamination in foods (10.

Molecular cloning of Bacillus sphaericus penicillin V amidase gene and its expression in Escherichia coli and Bacillus subtilis.

The Bacillus sphaericus gene coding for penicillin V amidase, which catalyzes the hydrolysis of penicillin V to yield 6-aminopenicillanic acid and phenoxyacetic acid, has been isolated by molecular cloning in Escherichia coli. The gene is contained within a 2.2-kilobase HindIII-PstI fragment and is expressed when transferred into E.

Efficient secretion and purification of human insulin-like growth factor I with a gene fusion vector in Staphylococci.

A novel approach for production of small polypeptides, using a staphylococcal protein A vector, is described. This system is used to express, secrete and purify human insulin-like growth factor I (IGF-I). A fusion protein consisting of protein A and IGF-I is recovered in high yield by passing the culture medium through an IgG affinity column.

Ochratoxin A in blood of slaughter pigs.

The global ochratoxin A contamination of Swedish feed cereals was studied by analysis of pig blood samples from 122 different herds. The samples were collected at seven Swedish slaughterhouses. The ochratoxin A analysis showed 21% of the samples to contain greater than or equal to 2 ng ochratoxin A per ml.

Intermediary Metabolism in Clostridium acetobutylicum: Levels of Enzymes Involved in the Formation of Acetate and Butyrate.

The levels of seven intermediary enzymes involved in acetate and butyrate formation from acetyl coenzyme A in the saccharolytic anaerobe Clostridium acetobutylicum were investigated as a function of time in solvent-producing batch fermentations. Phosphate acetyltransferase and acetate kinase, which are known to form acetate from acetyl coenzyme A, both showed a decrease in specific activity when the organism reached the solvent formation stage. The three consecutive enzymes thiolase, beta-hydroxybutyrylcoenzyme A dehydrogenase, and crotonase exhibited a coordinate expression and a maximal activity after growth had ceased.

Complete sequence of the staphylococcal gene encoding protein A. A gene evolved through multiple duplications.

The gene coding for protein A from Staphylococcus aureus has been isolated by molecular cloning, and a subclone containing an 1.8-kilobase insert was found to give a functional protein A in Escherichia coli. The complete nucleotide sequence of the insert, including the structural gene and the 5' and 3' flanking sequences, has been determined.

An improved positive selection plasmid vector constructed by oligonucleotide mediated mutagenesis.

An Escherichia coli plasmid vector, pUN121, has been constructed which allows for positive selection of transformants harboring DNA inserts. The positive selection of transformants harboring DNA inserts. The vector is based on plasmid pTR262 (Roberts et al.

Gene fusion vectors based on the gene for staphylococcal protein A.

Two plasmid vectors, containing the gene coding for staphylococcal protein A and adapted for gene fusion, have been constructed. These vectors will allow fusion of any gene to the protein A gene, thus giving hybrid proteins which can be purified, in a one-step procedure, by IgG affinity chromatography. As an example of the practical use of such vectors, the protein A gene has been fused to the lacZ gene of Escherichia coli.

Enzymatic synthesis of (+)- and (-)-bisdechlorogeodin with sulochrin oxidase from Penicillium frequentans and Oospora sulphurea-ochracea.

Sulochrin oxidase is a blue copper-containing glycoenzyme that catalyzes a stereospecific formation of bisdechlorogeodin from sulochrin. The enzyme has been isolated from Penicillium frequentans and Oospora sulphurea-ochracea which catalyzes the formation of (+)-form and (-)-form of bisdechlorogeodin respectively. The Penicillium enzyme has a molecular weight of 157,000 and contains 19.

The distribution of the NADPH regenerating mannitol cycle among fungal species.

The mannitol cycle is an important NADPH regenerating system in Alternaria alternata. The cycle is built up to the following enzymes: mannitol 1-phosphate dehydrogenase, mannitol 1-phosphatase, mannitol dehydrogenase and hexokinase. The net reaction of one cycle turn is: NADH + NADP+ + ATP leads to NAD+ + NADPH + ADP + Pi.

Ochratoxin A in blood from slaughter pigs in Sweden: use in evaluation of toxin content of consumed feed.

Samples of pig blood, intended for ochratoxin A analysis, were collected from pigs of 279 randomly selected herds. The samples were obtained at nine different slaughterhouses from different areas of Sweden. Pigs from 47 herds (16.

Ochratoxin A in pig blood: method of analysis and use as a tool for feed studies.

A procedure is presented for screening the quality of feed in respect to ochratoxin A contamination based upon the analysis of ochratoxin A in pig blood. Representative samples from large feed lots may be obtained by using pigs as in vivo sample collectors which enrich the toxin and forms homogeneous samples in the blood. The spectrofluorometric procedure for ochratoxin A analysis (K.

Production of NADPH in the mannitol cycle and its relation to polyketide formation in Alternaria alternata.

The enzymes mannitol-1-phosphate dehydrogenase, mannitol-1-phosphatase, mannitol dehydrogenase and hexokinase participate in an enzymatic cycle in the fungus Alternaria alternata. One turn of the cycle gives the net result: NADH + NADP+ + ATP leads to NAD+ + NADPH + ADP + Pi. The cycle alone can meet the total need of NADPH formation for fat synthesis in the organism.

Analysis of ochratoxin B alone and in the presence of ochratoxin A, using carboxypeptidase A.

A method is described for ochratoxin B analysis, which is adapted to the earlier described method of ochratoxin A analysis, using carboxypeptidase A (K. Hult and S. Gatenbeck, J.

Intermediates in the barnol biosynthesis in Penicillium baarnense.

By using appropriate 14C-labelled phenolic substances as precursors in feeding experiments the following steps in barnol biosynthesis have been established: acetate + malonate leads to 2,4-dihydroxy-6-ethyl-5-methylbenzaldehyde leads to 1,3-dihydroxy-4,6-dimethyl-2-ethylbenzene leads to barnol. P. baarnense can also reduce orcylaldehyde and 2,4-dihydroxy-5,6-dimethylbenzaldehyde to dimethylresorcinol and trimethylresorcinol, respecitively.

Degradation of ochratoxin A by a ruminant.

The fate of ochratoxin A during incubation with contents from the four stomachs of the cow was studied. It was concluded that ochratoxin A was cleaved into the nontoxic ochratoxin alpha and phenylalanine by the contents from all but the abomasum.

A spectrophotometric procedure, using carboxypeptidase A, for the quantitative measurement of ochratoxin A.

In the method described, ochratoxin A is eleaved into ochratoxin alpha (free isocoumarin chromophore) and phenylaline, using carboxypeptidase. Detection is based on the difference in fluorescence excitation spectra of ochratoxin A (380 NM, maximum) and ochratoxin alpha (340 nm, maximum). The quantitation of ochratoxin A is based on the loss of fluorescence intensity at 380 nm.

Regulation and metabolic background of polyketide formation. I. Effects of (-)-hydroxycitrate and metabolic roles of citrate and malate in fatty acid and polyketide formations.

The effects of (-)-hydroxycitrate on fatty acid and alternariol syntheses from glucose and acetate in Alternaria alternata were investigated. Fatty acid synthesis from glucose and acetate was inhibited by (-)-hydroxycitrate. The inhibition could partly be removed by the addition of malate or isocitrate.

Microbial production of tenuazonic acid analogues.

The fungus Alternaria tenuis normally produces tenuazonic acid (3-acetyl-5-secbutyltetramic acid). On supplementation of the culture substrate with l-valine and l-leucine, the organism formed two new tetramic acids, 3-acetyl-5-isopropyltetramic acid and 3-acetyl-5-isobutyltetramic acid, respectively. l-Phenylalanine was not utilized by the organism as a tetramic acid precursor.