Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons.

Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 µg/g) were higher than the mean FB2 levels (0.42 µg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations.

Identification of Aspergillus flavus isolates as potential biocontrol agents of aflatoxin contamination in crops.

Aspergillus flavus, a haploid organism found worldwide in a variety of crops, including maize, cottonseed, almond, pistachio, and peanut, causes substantial and recurrent worldwide economic liabilities. This filamentous fungus produces aflatoxins (AFLs) B1 and B2, which are among the most carcinogenic compounds from nature, acutely hepatotoxic and immunosuppressive. Recent efforts to reduce AFL contamination in crops have focused on the use of nonaflatoxigenic A. flavus strains as biological control agents. Such agents are applied to soil to competitively exclude native AFL strains from crops and thereby reduce AFL contamination. Because the possibility of genetic recombination in A. flavus could influence the stability of biocontrol strains with the production of novel AFL phenotypes, this article assesses the diversity of vegetative compatibility reactions in isolates of A. flavus to identify heterokaryon self-incompatible (HSI) strains among nonaflatoxigenic isolates, which would be used as biological controls of AFL contamination in crops. Nitrate nonutilizing (nit) mutants were recovered from 25 A. flavus isolates, and based on vegetative complementation between nit mutants and on the microscopic examination of the number of hyphal fusions, five nonaflatoxigenic (6, 7, 9 to 11) and two nontoxigenic (8 and 12) isolates of A. flavus were phenotypically characterized as HSI. Because the number of hyphal fusions is reduced in HSI strains, impairing both heterokaryon formation and the genetic exchanges with aflatoxigenic strains, the HSI isolates characterized here, especially isolates 8 and 12, are potential agents for reducing AFL contamination in crops.

Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons

Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 µg/g) were higher than the mean FB2 levels (0.42 µg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations.

Aerobic exercise improves reverse cholesterol transport in cholesteryl ester transfer protein transgenic mice.

We analyzed the effect of a 6-week aerobic exercise training program on the in vivo macrophage reverse cholesterol transport (RCT) in human cholesteryl ester transfer protein (CETP) transgenic (CETP-tg) mice. Male CETP-tg mice were randomly assigned to a sedentary group or a carefully supervised exercise training group (treadmill 15 m/min, 30 min sessions, five sessions per week). The levels of plasma lipids were determined by enzymatic methods, and the lipoprotein profile was determined by fast protein liquid chromatography (FPLC). CETP activity was determined by measuring the transfer rate of ¹4C-cholesterol from HDL to apo-B containing lipoproteins, using plasma from CETP-tg mice as a source of CETP. The reverse cholesterol transport was determined in vivo by measuring the [³H]-cholesterol recovery in plasma and feces (24 and 48 h) and in the liver (48 h) following a peritoneal injection of [³H]-cholesterol labeled J774-macrophages into both sedentary and exercise trained mice. The protein levels of liver receptors were determined by immunoblot, and the mRNA levels for liver enzymes were measured using RT-PCR. Exercise training did not significantly affect the levels of plasma lipids or CETP activity. The HDL fraction assessed by FPLC was higher in exercise-trained compared to sedentary mice. In comparison to the sedentary group, a greater recovery of [³H]-cholesterol from the injected macrophages was found in the plasma, liver and feces of exercise-trained animals. The latter occurred even with a reduction in the liver CYP7A1 mRNA level in exercised trained animals. Exercise training increased the liver LDL receptor and ABCA-1 protein levels, although the SR-BI protein content was unchanged. The RCT benefit in CETP-tg mice elicited by exercise training helps to elucidate the role of exercise in the prevention of atherosclerosis in humans.

Induction of IgE antibodies with predefined specificity in rhesus monkeys with recombinant birch pollen allergens, Bet v 1 and Bet v 2.

BACKGROUND: Recombinant birch pollen allergens Bet v 1 and Bet v 2 (birch profilin) have been characterized in vitro previously. OBJECTIVE: To establish a close-to-man model of type I allergy, recombinant birch pollen allergens were injected into rhesus monkeys. METHODS: The allergens were expressed in Escherichia coli, purified to homogeneity and injected into rhesus monkeys with aluminium hydroxide as adjuvans. The development of type I allergy was monitored by measurement of specific IgE, in vitro histamine release tests, cellular proliferation assays, skin testing, and bronchial provocation tests. RESULTS: Immunized rhesus monkeys displayed symptoms of type I allergy comparable to those of allergic patients, and cross-reactivity of IgE antibodies with Bet v 1 and Bet v 2 homologous allergens was observed. Systemic application of corticosteroids during secondary immunizations suppressed specific antibody responses. CONCLUSION: Recombinant birch pollen allergens (Bet v 1 and Bet v 2) were effective to establish a close-to-man model of natural type I allergy in rhesus monkeys, allowing study of specific IgE regulation in vivo.

Purification and characterization of recombinant Bet v I, the major birch pollen allergen. Immunological equivalence to natural Bet v I.

Pollen from trees of the order Fagales (e.g. birch, alder, hazel, oak, and hornbeam) are a major cause of Type I allergies observed in early spring. Previously, we reported the cloning and sequencing of Bet v I, the major birch pollen allergen, which showed high sequence similarities to a family of plant pathogen-activated genes (Breiteneder, H., Pettenburger, K., Bito, A., Valenta, R., Kraft, D., Rumpold, H., Scheiner, O., and Breitenbach, M. (1989) EMBO J. 8, 1935-1938). Here, we present the results on the expression, purification, and characterization of recombinant Bet v I produced in Escherichia coli as fusion and non-fusion protein, respectively. The purified recombinant proteins were analyzed to verify purity and structural integrity, and their immunological properties were compared to those of Bet v I isolated from birch pollen (natural Bet v I). Immunoblot analyses showed that the recombinant proteins are specifically recognized by monoclonal antibodies raised against natural Bet v I as well as by IgE from birch pollen-allergic patients. However, enzyme-linked immunosorbent assays revealed a decreased IgE-binding activity of the recombinant fusion Bet v I compared to the non-fusion and natural Bet v I proteins, which probably results from conformational changes due to the fusion tail. Recombinant non-fusion Bet v I was equivalent to natural Bet v I with respect to IgE-binding properties, the ability to induce in vitro proliferation of allergen-specific T-cell clones, and the ability to release histamine from basophils derived from birch pollen-allergic patients.

Differential expression of proline-rich proteins in rabbit salivary glands.

Salivary glands synthesize and secrete an unusual family of proline-rich proteins (PRPs) that can be broadly divided into acidic and basic PRPs. We studied the tissue-specific expression of these proteins in rabbits, using antibodies to rabbit acidic and basic PRPs as well as antibodies and cDNA probes to human PRPs. By immunoblotting, in vitro translation, and Northern blotting, basic PRPs could be readily detected in the parotid gland but were absent in other salivary glands. In contrast, synthesis in vitro of acidic PRPs was detected in parotid, sublingual, and submandibular glands. Ultrastructural localization with immunogold showed heavy labeling with antibodies to acidic PRPs of secretory granules of parotid acinar cells and sublingual serous demilune cells. Less intense labeling occurred in the seromucous acinar cells of the submandibular gland. With antibodies to basic PRPs, the labeling of the parotid gland was similar to that observed with antibodies to acidic PRPs, but there was only weak labeling of granules of a few sublingual demilune cells, and no labeling of the submandibular gland. These results demonstrate a variable pattern of distribution of acidic and basic PRPs in rabbit salivary glands. These animals are therefore well suited for study of differential tissue expression of PRPs.

Adenine nucleotide contents and ATPases activities in porcine deciduous dental pulp during the root formation, in fully formed root and during root resorption phases.

Nucleotide content and activity of certain enzymes were compared in pigs of various ages in order to study the energetic metabolism of deciduous dental pulps in the three phases of the cycle of tooth ontogeny, namely, root formation, fully formed root and root resorption phases. The frozen pulps were removed with the help of a screw vise and analysed for ATP, ADP and AMP contents and Ca2+ and Mg2+-ATPases activities. The highest ATP content in the first deciduous molar pulp was found when the tooth was still in an intrabony position. The calculated energy charge, although low for all groups, at this stage of development, indicated an activation of the consuming processes. In the root resorption phase, lowest ATP content and higher Ca2+ and Mg2+-ATPases activities were observed.

Adenine nucleotide changes in submandibular salivary glands of rats following isoproterenol or incisor tooth amputation.

Male rats (180-220 g) were injected daily with isoproterenol (2 mg/kg of body weight) for up to 6 days, or their incisor teeth were amputated on every other day for up to six amputations. The animals were subdivided into groups killed 12 or 24 h after the first or last intervention. In the development of sialadenosis caused by isoproterenol, the levels of ATP were greater (13-30%), while those of AMP were lower (13-19%) in the experimental groups. No variation was noted in ADP content. In tooth-amputated animals, only the five and six amputation subgroups showed higher values for ATP (approx. 17%), and ADP (12 and 15%, respectively). The inorganic phosphate level was lower in both experimental groups (between 11-28% for isoproterenol and 13-22% for amputation). Thus isoproterenol caused different metabolic responses in submandibular salivary glands from those induced by incisor amputation.

Changes in glucose metabolism in submandibular salivary glands of rats after isoproterenol or incisor-tooth amputation.

Rats were injected daily with isoproterenol (2 mg/kg of body wt) for up to five days, or their incisor teeth were amputated on every other day for up to five amputations. The animals were subdivided in two subgroups killed 12 or 24 h after the first or last intervention. At 12 h all enzymes except hexokinase (HK) and pyruvate kinase (PFK) showed decreased activities after isoproterenol. After incisor amputation, only increased HK and PFK activities were observed. With both procedures, there is activation of beta-adrenergic receptors but results show that different biochemical events take place, suggesting different mechanisms.

Changes in glucose metabolism in submandibular salivary glands of rats after isoproterenol or incisor-tooth amputation / Alterações do metabolismo da glicose em glândulas sumandibulares de ratos tratados com isoproterenol ou submetidos a amputação dos dentes incisivos

Rats were infected daily with isoproterenol (2 mg/kg of body wt) for up to five days, or their incisor teeth were amputated on every other day for up to five amputations. The animals were subdivided in two subgroups killed 12 or 24 h after the first or last intervention. At 12 h all enzymes except hexokinase (HK) and pyruvatekinase (PFK) showed decreased activities after isoproterenol. After incisor amputation, only increased HK and PFK activities were observed. With both procedures, there is activation of ß-adrenergic receptors but results show that different biochemical events take place, suggesting different mechanisms

Different responses of the submandibular salivary glands and liver of rats subjected to excess vitamin A: study on glycogen metabolism.

The effect of excess vitamin A on glycogen metabolism in the submandibular salivary gland, as compared to that in liver was studied. Contrary to what has been previously reported for the liver, either using from 1 to 6 X 15 000 or 2 X 30 000 U.I. vitamin A, the glycogen content in the submandibular salivary gland was lower in the hypervitaminotic rats. The total phosphorylase activity was reduced in the groups receiving lower vitamin A doses.