Evaluation of methods used to determine ochratoxin A in coffee beans.

A comparative study was conducted to evaluate four previously reported methods that proved to have a recovery greater than 80% for the determination of different levels of ochratoxin A (OTA) in green and roasted coffee beans and to select an accurate, sensitive, and less-expensive technique between the existing methods. The results indicated that the Association of Official Analytical Chemists (AOAC) official method for the extraction of OTA in green coffee and determination by high-performance liquid chromatography (HPLC) is recommended as an efficient method for the routine analyses of OTA in green and ground roasted coffee beans. This method proved to be an accurate, sensitive, and less-expensive method that employs routine materials and available equipment. Although the immunoaffinity column/HPLC procedure tested showed a significantly higher percentage than the AOAC recommended method, it is recommended for use in processed coffee beans where low concentrations of OTA may be expected to be detected.

Incidence, level, and behavior of aflatoxins during coffee bean roasting and decaffeination.

Screening for aflatoxins (Afs), isolation and identification of Aspergillus flavus, and the effect of decaffeination and roasting on the level of contamination in coffee beans are studied. The percent frequency of A. flavus ranged between 4 and 80% in green coffee beans (GCB), whereas in ground roasted coffee beans (GRCB), it ranged between 1 and 71%. Aflatoxins were detected in 76.5 and 54.6% of the infected samples with averages of 4.28 and 2.85 microg/kg of GCB and GRCB, respectively. Roasting was demonstrated to lower the concentration of Afs in GCB. The Afs levels were reduced by approximately 42.2-55.9% depending on the type and temperature of roasting. The highest yields of Afs were detected in the decaffeinated green coffee beans (24.29 microg/kg) and roasted coffee beans (16.00 microg/kg). The growth of A. flavus in liquid medium containing 1 or 2% caffeine was reduced by 50%, and the level of aflatoxin in the medium was undetectable.

Effect of oil extracted from some medicinal plants on different mycotoxigenic fungi.

Essential oils of 12 medicinal plants were tested for inhibitory activity against Aspergillus flavus, A. parasiticus, A. ochraceus and Fusarium moniliforme. The oils of thyme and cinnamon (< or = 500 ppm), marigold (< or = 2000 ppm), spearmint, basil, quyssum (3000 ppm) completely inhibit all the test fungi. Caraway was inhibitory at 2000 ppm against A. flavus, A. parasiticus and 3000 ppm against A. ochraceaus and F. moniliforme. A. flavus, A. ochraceus, A. parasiticus and F. moniliforme were completely inhibited by anise at< or = 500 ppm. However, chamomile and hazanbul at all concentrations were partially effective against the test toxigenic fungi. The results indicate that the test toxigenic fungi are sensitive to the 12 essential oils, and particularly sensitive to thyme and cinnamon. The results also showed that the essential oils of thyme, cinnamon, anise and spearmint have more effect on fungal development and subsequent mycotoxin production in wheat grains. The extent of inhibition of fungal growth and mycotoxin production was dependent on the concentration of essential oils used.

Monitoring the preventive effect of hydrogen peroxide and gamma-radiation of aflatoxicosis in growing rabbits and the effect of cooking on aflatoxin residues.

The objective of the present study was the prevention of aflatoxicosis of growing rabbits fed aflatoxin (AF)-contaminated diet (833 microg of aflatoxins/kg) using 5% hydrogen peroxide (H2O2) and gamma-radiation at a dose level of 500 krad (5 kGy) and fed to growing rabbits. A total of 24 New Zealand white rabbits were divided into three groups. The experimental diets included AF-contaminated diet; AF-decontaminated diet, and AF-free diet (control). The obtained data showed significant reduction (p < 0.05) in live body weight and body weight gain of rabbits that fed on AF-contaminated diet as well as AF-decontaminated diet relative to control. There were no differences in feed consumption among the three groups; feed efficiency reduced significantly for AF-contaminated and AF-decontaminated groups. Mortality percentage was 25% for AF-contaminated and AF-decontaminated groups. Relative weight of the liver increased in animals fed AF-contaminated and AF-decontaminated diets, whereas the relative weight of kidneys decreased for both. There was no difference in total protein, but the levels of albumin and globulin were altered in rabbits receiving AF-contaminated diet. Serum enzymes (alanine amino transferase and aspartate amino transferase) activity increased significantly in rabbits that received AF-contaminated as well as AF-decontaminated diets. Histopathological examination revealed particularly alteration in liver and kidneys of rabbits fed AF-decontaminated diet. Results showed that the percentage of aflatoxin reduction ranged between 67 and 80% in boiled liver and between 79 and 90.5% in fried liver, whereas complete reduction in AF was found after boiling followed by frying. These findings indicate that the use of H2O2 and gamma-radiation for the destruction of aflatoxins in contaminated diet induces adverse effects in the animals.

Changes in concentration of pesticide residues in potatoes during washing and home preparation.

Monitoring of pesticide residues in potato tubers and their prepared products ("pommes frites" and chips) was undertaken. Experiments were carried out to determine changes in concentration due to the washing, peeling and cooking process (blanching and frying) to assess the stability of pesticides in potatoes and their products. Pesticide residues were quantified by using gas chromatography. Results show that malathion, HCB, lindane and p,p-DDD were predominant in potatoes and their products. The highest mean was detected in potatoes, followed by pommes frites, while the lowest mean was recorded in chips. On the other hand, potato skin samples were found to contain the highest levels of DDT and its derivatives, lindane and HCB. Peeling was necessary to remove the greatest amount of pesticides in the skin. Washing with water and/or other solutions as well as the cooking process (blanching and frying) helped to eliminate most of the pesticide residues from the potato tubers.

FISH mapping of the 5S and 18S-28S rDNA loci in different species of Glycine.

Wild germplasms are often the only significant sources of useful traits for crops, such as soybean, that have limited genetic variability. Before these germplasms can be effectively manipulated they must be characterized at the cytological and molecular levels. Modern soybean probably arose through an ancient allotetraploid event and subsequent diploidization of the genome. However, wild Glycine species have not been intensively investigated for this ancient polyploidy. In this article we determined the number of both the 5S and 18S-28S rDNA sequences in various members of the genus Glycine using FISH. Our results distinctly establish the loss of a 5S rDNA locus from the "diploid" (2n = 40) species and the loss of two from the (2n = 80) polyploids of GLYCINE: A similar diploidization of the 18S-28S rDNA gene family has occurred in G. canescens, G. clandestina, G. soja, and G. max (L.) Merr. (2n = 40). Although of different genome types, G. tabacina and G. tomentella (2n = 80) both showed two major 18S-28S rDNA loci per haploid genome, in contrast to the four loci that would be expected in chromosomes that have undergone two doubling events in their evolutionary history. It is evident that the evolution of the subgenus Glycine is more complex than that represented in a simple diploid-doubled to tetraploid model.

Effect of carnosine administration on certain metabolic parameters in bilharzial infected hamsters.

This study was designed to test the ability of carnosine to cure the metabolic disturbances induced by Schistosoma mansoni parasite. Results indicate that parasitic infection caused elevation of liver weight/body weight of S. mansoni infected hamsters, induced lipid peroxidation and reduced glycogen level. Moreover, the adenylate energy charge (AEC), ATP/ADP and ATP/AMP concentration ratios were markedly lower in infected hamsters. Administration of carnosine (10 mg/day) for 15 days either concurrent with infection, 2 and 4 weeks post exposure was effective in reducing worm burden and egg count only when given at the time of infection. It was also effective in renormalizing most of the measured parameters confirming the glycogen repletion, the antioxidant and AEC correcting actions of carnosine.

A continuous high-resolution physical map spanning 17 megabases of the q12, q13.1, and q13.2 cytogenetic bands of human chromosome 19.

We report the construction of a high-resolution physical map of a 17-Mb region that encompasses the entire q12, q13.1, and q13.2 bands of human chromosome 19. The continuous map extends from a region approximately 400 kb centromeric of the D19S7 marker to the excision repair cross-complementing rodent repair deficiency complementation group 1 (ERCC1) locus. The ordered clone map has been obtained starting from a foundation of cosmid contigs assembled by automated fingerprinting and localized to the cytogenetic map by fluorescence in situ hybridization (FISH). Clonal continuity of the map has been achieved by binning and linking the premapped cosmid contigs by means of yeast artificial chromosomes (YACs). The map consists of a single contig composed of 169 YAC members (minimal spanning path of 18 YACs) linking 165 cosmid contigs. Eighty percent, or about 13.2 Mb of the entire region spanned by the map, has been resolved to the EcoRI restriction map level. Twenty-nine sequence-tagged sites associated with genetic markers or derived from FISH-mapped cosmids have been placed on the map. In addition to the ERCC1 gene area, the map includes the location of the creatine kinase muscle locus (CKM), imidazoledipetidase (PEPD), glucophosphate isomerase (GPI), myelin-associated glycoprotein (MAG), the apolipoprotein E and C (APOE and APOC) genes, and the ryanodine receptor (RYR1) gene. This type of map provides a source of continuously overlapping DNA segments at a level of resolution two orders of magnitude higher than that obtained using YACs alone. In addition, it provides ready-to-use reagents for detailed analyses at the gene level, FISH studies of chromosomal aberrations, and DNA sequencing.

Genetic analyses of rDNA spacer-length variation in barley.

The genetic mechanism controlling the inheritance of single and multiple spacer-length variant (slv) phenotypes in barley was investigated in six F2 segregating populations. The results indicated that two independently assorting loci, each with co-dominant alleles, govern genetic variability for rDNA in barley regardless of the number of bands expressed by a given phenotype. The following chromosomal locations are proposed: sl variants 1, 4, 5, 6, and 7 on chromosome 7, and sl variants 7, 8, 9, 12, and 13 on chromosome 6; sl variant 7 is thus located on both of the chromosomes.

Ribosomal DNA spacer-length polymorphisms in barley: mendelian inheritance, chromosomal location, and population dynamics.

Spacer-length (sl) variation in ribosomal RNA gene clusters (rDNA) was surveyed in 502 individual barley plants, including samples from 50 accessions of cultivated barley, 25 accessions of its wild ancestor, and five generations of composite cross II (CCII), an experimental population of barley. In total, 17 rDNA sl phenotypes, made up of 15 different rDNA sl variants, were observed. The 15 rDNA sl variants comprise a complete ladder in which each variant differs in length from adjacent variants by approximately equal to 115 nucleotide pairs. Studies of four rDNA sl variants in an F2 population showed that these variants are located at two unlinked loci, Rrn1 and Rrn2, each with two codominant alleles. Using wheat-barley addition lines, we determined that Rrn1 and Rrn2 are located on chromosomes 6 and 7, respectively. The nonrandom distribution of sl variants between loci suggests that genetic exchange occurs much less frequently between than within the two loci, which demonstrates that Rrn1 and Rrn2 are useful as new genetic markers. Frequencies of rDNA sl phenotypes and variants were monitored over 54 generations in CCII. A phenotype that was originally infrequent in CCII ultimately became predominant, whereas the originally most frequent phenotype decreased drastically in frequency, and all other phenotypes originally present disappeared from the population. We conclude that the sl variants and/or associated loci are under selection in CCII.

Selection and identification of a spontaneous alien chromosome translocation in wheat.

A wheat (Triticum aestivum L. emend Thell) disomic addition line (2n = 6x = 44), SH1-152-2, with a pair of Elytrigia pontica (Podp.) Holub 2n = 10x = 70 [syn. Agropyron elongatum (Host) P.B.] chromosomes controlling blue aleurone color was crossed with a short-statured spring wheat ;Sonora 64' (T. aestivum). Isoline pairs of blue-disomic addition lines and nonblue euploid lines were produced by selecting plants segregating for blue aleurone for 12 generations. Nineteen of 20 blue aleurone lines were 2n = 44 addition lines, and one had 2n = 42 chromosomes. Several lines of evidence showed that this line had a spontaneous translocation in which the beta arm of wheat chromosome 4A was replaced by an Elytrigia chromosome arm carrying the blue aleurone gene. The Elytrigia chromosome in SH1-152-2 appeared to be homologous with E. pontica chromosome 4el(1), which also carries the blue aleurone gene. It was concluded that the spontaneous translocation originated from simultaneous misdivision of univalents and subsequent reunion at the centromere of chromosome arm 4Aalpha with the Elytrigia chromosome arm.

Effects of an Agropyron chromosome on endosperm proteins in common wheat Triticum aestivum L.).

An Agropyron chromosome having a gene conferring blue color on the aleurone layer of the kernel endosperm causes a 15% increase in total grain protein content when it is added to the common wheat (2n=42) complement. In contrast, there is no effect of this chromosome on total protein content if it replaced part of a wheat chromosome. Endosperm protein components of isolines having blue aleurone due to the Agropyron chromosomes being added (2n=44) or translocated (2n=42) were compared to normal nonblue isoline counterparts. Gliadin proteins separated by aluminum lactate (pH 3.2) polyacrylamide gel electrophoresis (PAGE) in one or two dimensions showed greater staining intensity for the blue addition isolines (2n=44) than nonblue (2n=42) isolines. However the 42-chromosome blue isoline did not show increased protein staining over the nonblue isoline, but at least five protein differences were detected between the lines. SDS-PAGE showed that blue and nonblue differences were expressed primarily in the gliadins, but also in the glutenin, globulin, and albumin proteins.