Fermentability of grape must after inhibition with dimethyl dicarbonate (DMDC)

Dimethyl dicarbonate (DMDC) was added to grape must and to synthetic media and results showed that, at 20 degrees C, 150 mg.L(-)(1) DMDC completely inhibited the fermentation of a grape must that was previously inoculated with 10(6) cells.mL(-)(1) Saccharomyces bayanus and Saccharomyces uvarum. Brettanomyces intermedius, Candida guilliermondii, Hansenula jadinii, Hansenula petersonii, Kloeckera apiculata, Pichia membranaefaciens, and Saccharomyces cerevisiae were inhibited by 250 mg.L(-)(1). Candida valida was inhibited in the presence of 350 mg.L(-)(1), whereas Hanseniaspora osmophila, Saccharomycodes ludwigii, Schizosaccharomyces pombe, and Zygosaccharomyces bailii required 400 mg.L(-)(1). Delay of fermentation (but not inhibition) was noted in the presence of 400 mg.L(-)(1) for the following cultures: Brettanomyces anomalus, Hanseniaspora uvarum, Metschnikowia pulcherrima, Schizosaccharomyces japonicus, Torulaspora delbrueckii, and Zygosaccharomyces florentinus. Acetobacter aceti and Lactobacillus sp. were completely inhibited using 1000 and 500 mg.L(-)(1) DMDC, respectively. The fermentation of a grape must inoculated with 10(6) cells.mL(-)(1) of different wine yeasts was delayed for 4 days after the prior addition of 200 mg.L(-)(1) of DMDC; 200 mg.L(-)(1) DMDC did not show any residual inhibitory effect after 12 h, nor did 300 mg.L(-)(1) 24 h after the addition. In cellar experiments, indigenously contaminated grape musts (with and without skins) showed a delay in fermentation of 48 h after the addition of only 50 mg.L(-)(1) DMDC. The possibility of using DMDC (as pure grade as commercially available) in grape must as a disinfectant for the decontamination of musts indigenously contaminated with wild yeast should be considered seriously, despite its apparent low solubility in water.     

Metabolism of stevioside and rebaudioside A from Stevia rebaudiana extracts by human microflora

Stevia rebaudiana standardized extracts (SSEs) are used as natural sweeteners or dietary supplements in different countries for their content of stevioside or rebaudioside A. These compounds possess up to 250 times the sweetness intensity of sucrose, and they are noncaloric and noncariogenic sweeteners. The aim of this study was to investigate the in vitro transformation of stevioside and rebaudioside A after incubation with human microflora, the influence of these sweeteners on human microbial fecal community and which specific groups metabolize preferentially stevioside and rebaudioside A. The experiments were carried out under strict anaerobic conditions in batch cultures inoculated with mixed fecal bacteria from volunteers. The hydrolysis was monitored by HPLC coupled to photodiode array and mass spectrometric detectors. Isolated bacterial strains from fecal materials incubated in selective broths were added to stevioside and rebaudioside A. These sweeteners were completely hydrolyzed to their aglycon steviol in 10 and 24 h, respectively. Interestingly, the human intestinal microflora was not able to degrade steviol. Furthermore, stevioside and rebaudioside A did not significantly influence the composition of fecal cultures; among the selected intestinal groups, bacteroides were the most efficient in hydrolyzing Stevia sweeteners to steviol.     

Chondroitin sulfate proteoglycan-4: a biomarker and a potential immunotherapeutic target for canine malignant melanoma

Chondroitin sulfate proteoglycan-4 (CSPG4), also known as high molecular weight-melanoma associated antigen (HMW-MAA), is a membrane-bound chondroitin sulfate proteoglycan highly expressed by human melanoma cells. This phylogenetically conserved tumour antigen plays an important biological role in human melanoma, where it is used as a marker to diagnose forms with unusual characteristics, such as desmoplastic melanoma, and to detect melanoma cells in lymph nodes and peripheral blood, and as a target for immunotherapy because of its restricted distribution in normal tissues. To identify suitable targets to develop novel approaches of treating canine melanoma, CSPG4 was studies to see whether it is expressed in canine malignant melanomas. Immunohistochemical staining of 65 canine malignant melanomas with an anti-human CSPG4-specific antibody detected CSPG4 in 37 cases (56.9%). Positive staining was more frequent, albeit not significantly, in amelanotic compared to melanotic tumours and was statistically associated with tumours having both melanin and the epithelioid histotype. The frequency of CSPG4 expression was similar to that of other melanoma antigens used as diagnostic markers for canine malignant melanoma, such as Melan A and the protein recognized by the PNL2 monoclonal antibody. The results suggest that CSPG4 constitutes a new potential immunohistochemical marker of canine malignant melanoma and may represent an immunotherapeutic target as in humans.     

Impact and control of the cone tortricid Pseudococcyx tessulatana (Staudinger), damaging the cone crop of a selected clone of cypress (Cupressus sempervirens L.) in Italy

The green cypress (Cupressus sempervirens) is of great interest for ornamental, reforestation and windbreak use in the whole Mediterranean basin. In Italy, seed material selected for resistance to the fungus Seiridium cardinale is produced in seed orchards by controlled crosses of parent trees. The insect pest showing the highest impact on seed cone production is Pseudococcyx tessulatana (Lep.; Tortricidae), which attacks cones during the initial growth period as well as full-grown cones. The impact on the seed cone crop of the tortricid was estimated on a clone patented for its resistance to cypress canker (Agrimed 1). The attack was inversely related to the cone crop, as it concerned 36.7% of cones in 1999 (high crop year) and the 66% in 2000 (low crop year). In both years, about 90% of the surveyed branches revealed cones attacked by P. tessulatana by the 1^st life-cycle larvae, whereas only 40% of branches were also attacked by the larvae of the 2^nd life cycle. The highest attack rate per branch was always observed on branches bearing a low number of cones. The potential of two control methods against P. tessulatana to protect cones which result from crossing a mother tree Agrimed 1 with selected father trees was also evaluated in 2000. The protection given by a sleeve surrounding the branch was almost complete (0.4% cone mortality), whereas a cone mortality of 24.3% was observed on branches treated by the insecticide diflubenzuron. Sleeves appear to be useful to protect branches on which special crosses were done, but are expensive and time-consuming and may favour the attack of the mealybug Planococcus vovae inside the sleeve. The insecticide application may represent a valid alternative, especially when protection should be directed toward a high number of branches.     

Fate of feed plant DNA monitored in water buffalo (Bubalus bubalis) and rabbit (Oryctolagus cuniculus)

The effect of the digestion process in the gastro-intestinal tract (GIT) of animal models on the fate and integrity of plant DNA has been widely evaluated since DNA availability and integrity is a key factor for hypothetical horizontal gene transfer of recombinant DNA from GM crop-derived feeds to animal and human gut microflora. In this study, plant DNA sequences from high and low copy number genes were monitored in GIT and tissues of buffaloes and rabbits. Using a real-time PCR approach to track plant DNA in animal samples, we demonstrated the persistence of fragmented plant DNA blood and tissues of buffaloes and rabbits raised with conventional feeding.     

Impact and control of the cone tortricid Pseudococcyx tessulatana (Staudinger), damaging the cone crop of a selected clone of cypress (Cupressus sempervirens L.) in Italy

The green cypress (Cupressus sempervirens) is of great interest for ornamental, reforestation and windbreak use in the whole Mediterranean basin. In Italy, seed material selected for resistance to the fungus Seiridium cardinale is produced in seed orchards by controlled crosses of parent trees. The insect pest showing the highest impact on seed cone production is Pseudococcyx tessulatana (Lep.; Tortricidae), which attacks cones during the initial growth period as well as full-grown cones. The impact on the seed cone crop of the tortricid was estimated on a clone patented for its resistance to cypress canker (Agrimed 1). The attack was inversely related to the cone crop, as it concerned 36.7?% of cones in 1999 (high crop year) and the 66?% in 2000 (low crop year). In both years, about 90?% of the surveyed branches revealed cones attacked by P. tessulatana by the 1^st life-cycle larvae, whereas only 40?% of branches were also attacked by the larvae of the 2^nd life cycle. The highest attack rate per branch was always observed on branches bearing a low number of cones. The potential of two control methods against P. tessulatana to protect cones which result from crossing a mother tree “Agrimed 1” with selected father trees was also evaluated in 2000. The protection given by a sleeve surrounding the branch was almost complete (0.4?% cone mortality), whereas a cone mortality of 24.3?% was observed on branches treated by the insecticide diflubenzuron. Sleeves appear to be useful to protect branches on which special crosses were done, but are expensive and time-consuming and may favour the attack of the mealybug Planococcus vovae inside the sleeve. The insecticide application may represent a valid alternative, especially when protection should be directed toward a high number of branches.     

Glucan and fructan production by sourdough Weissella cibaria and Lactobacillus plantarum

After a large screening on sourdough lactic acid bacteria, exopolysaccharide (EPS)-forming strains of Weissella cibaria, Lactobacillus plantarum, and Pediococcus pentosaceus were selected. After 6 days of incubation at 30 degrees C, the synthesis of EPS in MRS-based broth ranged from 5.54 to 7.88 mg mL-1. EPS had an apparent molecular mass of ca. 104 Da. As shown by carbohydrate consumption, the synthesis of EPS was found from sucrose only. Two types of homopolysaccharides were synthesized: glucans simultaneously with growth and fructans after 1 day of incubation. Two protein bands of ca. 180-200 kDa were in situ detected on SDS-PAGE gels incubated with sucrose. PCR products of ca. 220 bp were found for L. plantarum PL9 (100% of identity to putative priming glycosyltransferase of L. plantarum WCFS1) and W. cibaria WC4 (80% of identity to putative glycosyltransferase, epsD, of Bacillus cereus G9241) by using hybrid primers for the priming gtf genes. Degenerated primers DexreuR and DexreuV showed a unique PCR product, and the predicted amino acid sequences were identical for W. cibaria WC4 and L. plantarum PL9. The sequence had similarity with polysaccharide biosynthesis glycosyltransferases. W. cibaria WC4 or L. plantarum LP9 synthesized ca. 2.5 g kg-1 EPS during sourdough fermentation with sucrose added. Compared to the sourdough started with an EPS-negative strain, the sourdough started with W. cibaria WC4 or L. plantarum LP9 increased the viscosity, and the resulting bread had higher specific volume and lower firmness. The synthesis of EPS by selected sourdough lactic acid bacteria could be considered as a useful tool to replace the additives for improving the textural properties of baked goods.     

Incompatibility in apricot (Prunus armeniaca L.): Methodological considerations

Summary

The recent introduction of new self-incompatible varieties of apricot has required further research on the extent of self-incompatibility in apricot and its genetic determinism. The different laboratory and field techniques utilized to date for incompatibility studies in apricot have often given markedly diverging results, leading to difficulty of interpretation. The purpose of this study was therefore to make a critical assessment of the reliability of the various methods, to obtain a more precise tool for compatibility studies. Forty-eight apricot crosses were assessed over a two-year period and the results compared using the normal field techniques (active pollination without bagging, active pollination with bagging and passive pollination) and laboratory tests (fluorescence test). The present study reports on some aspects of the different techniques and offers methodological suggestions for improved practical application of the various tests.