Gut production of GABA by a probiotic formula: an in vitro study

The objective of this study was to evaluate the influence of a probiotic formula on the production of neuroactive compounds in different parts of the colon in batch culture and in vitro gut simulator experiments. Thirteen lactic acid bacterial strains, belonging to the species Levilactobacillus brevis, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Ligilactobacillus salivarius, Streptococcus thermophilus, were characterised for their in vitro ability to produce neurotransmitters. L. brevis P30021 and L. plantarum P30025 were selected based on their capability to produce γ-aminobutyric acid (GABA) and acetylcholine in vitro. A probiotic formulation with potential psychobiotic activity was prepared and tested in a batch culture of human microbiota monitoring the formation of GABA and acetylcholine. Samples of the three colonic tracts were taken from the Simulator of the Human Intestinal Microbiota (SHIME®) evaluating the production of GABA and other neurotransmitters by LC-MS. Short chain fatty acids (SCFA) by GC and microbiota composition by 16S rRNA gene sequencing were also determined. Probiotic supplementation led to the formation of GABA and acetylcholine with a decrease in glutamate concentrations in the in vitro batch fermentation. Production of GABA after the treatment with probiotics was confirmed in the SHIME® short-term experiment. No differences in short-chain fatty acids were observed up to 72 h of fermentation. Different microbiota composition was found in the three different parts of the colon, with a higher abundance of Veillonellaceae in the ascending colon vessels. The probiotic-exposed microbiota showed higher levels of Bacteroides, a gut microbe associated with anti-inflammatory activities and a potential GABA producer. Results demonstrate the impact of the tested probiotic formula on gut microbiota structure and GABA production. In conclusion, the probiotic treatment changed the microbiota composition and increased neuroactive metabolites production, indicating promising potential as psychobiotics, even if further clinical evidence is needed to confirm the effectiveness of these probiotics in improving mental health.

Short communication: Short-time freezing does not alter the sensory properties or the physical stability of ultra-high-temperature hydrolyzed-lactose milk

In this study, the effect of milk freezing was studied, focusing on the changes in 1% and 3% fat UHT hydrolyzed-lactose milk after slow- (-20°C) and fast-rate freezing (-80°C) for 72 h. Changes on the sensory properties were first assessed by discriminant analysis (triangle test), and then by volatile organic compounds and color analysis. The milk emulsion stability was characterized by optical centrifugation, particle size analysis, and confocal microscopy. The sensory panel was not able to distinguish the milk subjected to freezing from the control (72 h at 20°C). The volatile organic compounds and color analysis demonstrated that both freezing rates did not cause any significant changes in the milk aroma or color characteristics. The results of physical properties confirmed that short-time freezing did not lead to a distinct destabilization, except for a slight increase in the mean particle diameter at -80°C. Taking all the results together, UHT hydrolyzed-lactose milk was not significantly altered during the operation of freezing and thawing and, therefore, short-time freezing at both -20°C and -80°C can be used for milk storage without altering the product.

Frozen storage of lesser mealworm larvae (Alphitobius diaperinus) changes chemical properties and functionalities of the derived ingredients

The effect of frozen storage on the chemical properties and ingredient functionalities of Lesser mealworms was investigated at -20 °C for 2 months. Major changes occurred in the first week of frozen storage. Proteins, among which heavy chain myosin, underwent denaturation and aggregation, as shown by a decrease in solubility, SDS-PAGE pattern, and Confocal Laser Scanning Microscopy. The ice melting point in larvae was -32.5 °C as determined by DSC: 25% of water is not frozen at -20 °C, possibly due to anti-freezing proteins preventing ice formation. The presence of unfrozen water favoured various enzymatic activities as shown by a pH decrease, indicating protein hydrolysis. The molecular changes during frozen storage increased the browning reactions due to phenoloxidase activity. Foaming ability, foam stability and gel network stability increased upon frozen storage due to protein denaturation. Results provide important information regarding the opportunity of frozen storage of insect larvae for both research and industrial purposes.

Rapid and noninvasive quality control of anhydrous milk fat by PTR-MS: The effect of storage time and packaging

In this study, proton transfer reaction-mass spectrometry (PTR-MS), coupled with a time-of-flight mass analyzer and a multipurpose automatic sampler, was evaluated as a rapid and nondestructive tool for the quality control of anhydrous milk fat. Anhydrous milk fats packed in cardboard and bag-in-box were compared during refrigerated shelf life at 4°C for 9 months. Anhydrous milk fat samples were taken at 120, 180, and 240 days and measured by PTR-MS during storage at 50°C for 11 days. Univariate and multivariate data analysis were performed in order to classify samples according to the packaging type and compare aromatic profiles. Markers related to both packaging and storage duration were identified, and all stored samples were clearly distinguishable from reference fresh samples. Significant differences in some key butter aroma compounds such as 2-pentanone, 2-heptanone, 2/3-methylbutanal, acetoin, and butanoic acid were observed between different types of packaging. During the refrigerated storage, differences related to packaging are more evident, while during the storage at 50°C, the fat oxidation induced by the high temperature becomes the most relevant phenomenon independently of the packaging type. These results indicate the importance of avoiding anhydrous milk fat storage at 50°C for long times during industrial production processes. All together data demonstrated the viability of PTR-MS as a rapid and high-sensitivity tool in agroindustry quality control program.

Consumption of extra-virgin olive oil rich in phenolic compounds improves metabolic control in patients with type 2 diabetes mellitus: a possible involvement of reduced levels of circulating visfatin

AIM

Phenolic compounds naturally contained in extra-virgin olive oil (EVOO) have demonstrated anti-inflammatory and antioxidant properties. The present study aimed at evaluating the effects of a polyphenol-rich extra-virgin olive oil (EVOO) (high-polyphenol EVOO, HP-EVOO) on the metabolic control and the production of specific pro-/anti-inflammatory adipokines in overweight patients with type 2 diabetes mellitus (T2D).

METHODS

Eleven overweight T2D patients not in treatment with insulin were invited to follow their habitual diet for a total of 8 weeks. During the first 4 weeks (wash-out period), they were asked to consume refined olive oil (ROO, polyphenols not detectable) and then to replace ROO with HP-EVOO (25 mL/day, 577 mg of phenolic compounds/kg) for the remaining 4 weeks. Anthropometric parameters, fasting glycaemia, glycated haemoglobin (HbA1c), high-sensitive C-reactive protein, plasma lipid profile, liver function and serum levels of TNF-α, IL-6, adiponectin, visfatin and apelin were assessed at the end of each 4-week period.

RESULTS

HP-EVOO consumption significantly reduced fasting plasma glucose (P = 0.023) and HbA1c (P = 0.039) levels as well as BMI (P = 0.012) and body weight (P = 0.012). HP-EVOO ingestion determined a reduction in serum level of aspartate aminotransferase (AST, P = 0.0056) and alanine aminotransferase (ALT, P = 0.024). Serum visfatin levels strongly decreased after HP-EVOO ingestion (P = 0.0021).

CONCLUSIONS

Daily consumption of polyphenol-rich EVOO might improve metabolic control and circulating inflammatory adipokines profile in overweight T2D patients.

Acrylamide mitigation strategies: critical appraisal of the FoodDrinkEurope toolbox

Not all the strategies proposed in FoodDrinkEurope toolbox have equal value in terms of efficacy and cost/benefit ratio.

Broccoli glucosinolate degradation is reduced performing thermal treatment in binary systems with other food ingredients

Glucosinolate (GL) stability has been widely studied in differentBrassicaspecies.

Alcoholic beverages and gastric epithelial cell viability: effect on oxidative stress-induced damage

Alcohol is known to cause damage to the gastric epithelium independently of gastric acid secretion. Different alcoholic beverages exert different damaging effects in the stomach. However, this has not been systematically evaluated. Moreover, it is not known whether the non-alcoholic components of alcoholic beverages also play a role in the pathogenesis of gastric epithelial cell damage. Therefore, this study was designed to evaluate whether different alcoholic beverages, at a similar ethanol concentration, exerted different damaging effect in gastric epithelial cells in vitro. Moreover, we evaluated whether pre-treatment of gastric epithelial cells with alcoholic beverages prevented oxidative stress-induced damage to gastric cells. Cell damage was assessed, in MKN-28 gastric epithelial cells, by MTT assay. Oxidative stress was induced by incubating cells with xanthine and xanthine oxidase. Gastric cell viability was assessed following 30, 60, and 120 minutes incubation with ethanol 17.5-125 mg/ml(-1) or different alcoholic beverages (i.e., beer, white wine, red wine, spirits) at comparable ethanol concentration. Finally, we assessed whether pre-incubation with red wine (with or without ethanol) prevented oxidative stress-induced cell damage. Red wine caused less damage to gastric epithelial cells in vitro compared with other alcoholic beverages at comparable ethanol concentration. Pre-treatment with red wine, but not with dealcoholate red wine, significantly and time-dependently prevented oxidative stress-induced cell damage.

CONCLUSIONS

1) red wine is less harmful to gastric epithelial cells than other alcoholic beverages; 2) this seems related to the non-alcoholic components of red wine, because other alcoholic beverages with comparable ethanol concentration exerted more damage than red wine; 3) red wine prevents oxidative stress-induced cell damage and this seems to be related to its ethanol content.

Potential prebiotic activity of oligosaccharides obtained by enzymatic conversion of durum wheat insoluble dietary fibre into soluble dietary fibre

BACKGROUND AND AIMS

Epidemiological evidence indicates that cereal dietary fibre (DF) may have several cardiovascular health benefits. The underlying mechanisms have not yet been elucidated. Here, the potential nutritional effects of physico-chemical properties modifications of durum wheat dietary fibre (DWF) induced by enzyme treatment have been investigated.

METHODS AND RESULTS

The conversion of the highly polymerised insoluble dietary fibre into soluble feruloyl oligosaccharides of DWF was achieved by a tailored enzymatic treatment. The in vitro fermentation and release of ferulic acid by intestinal microbiota from DWF before and after the enzymatic treatment were assessed using a gut model validated to mimic the human colonic microbial environment. Results demonstrated that, compared to DWF, the enzyme-treated DWF (ET-DWF) stimulated the growth of bifidobacteria and lactobacilli. Concurrently, the release of free ferulic acid by ET-DWF was almost three times higher respect to the control. No effect on the formation of short chain fatty acids was observed.

CONCLUSIONS

The conversion of insoluble dietary fibre from cereals into soluble dietary fibre generated a gut microbial fermentation that supported bifidobacteria and lactobacilli. The concurrent increase in free ferulic acid from the enzyme-treated DWF might result in a higher plasma ferulic acid concentration which could be one of the reasons for the health benefits reported for dietary fibre in cardiovascular diseases.

Lipodepsipeptides from Pseudomonas syringae are partially proteolyzed and are not absorbed by humans: an in vitro study

There are some concerns about the use of Pseudomonas-based products as biocontrol agents because of the hemolytic activity shown by their metabolites. The effects of Pseudomonas lipodepsipeptides (LDPs) on mammals via ingestion and the LDP degradation during the digestion and intestinal permeability have not been evaluated. In this research, the susceptibility of different LDPs to degradation was assayed with enzymatic gastrointestinal digestion, and intestinal permeability to LDPs was investigated in an in vitro system based on an intestinal cell layer system. Results demonstrated that trypsin and chymotrypsin hydrolyze up to 50% of the various LDPs, and that proteolysis was further increased by pronase E treatment. A decrease in LDP hemolytic activity matched LDP degradation during the various steps of the digestion process. Moreover, it was shown that syringomycin E (SRE), the main known LDP, was not able to cross the intestinal cell layer, suggesting that SRE does not reach the bloodstream in vivo. It was concluded that the Pseudomonas-based biocontrol products do not represent a serious risk for consumer health. In fact, LDPs possibly present on biocontrol-treated agricultural commodities would likely be partially digested by gastrointestinal enzymes and would not be absorbed at the intestinal level.

Development of a tomato-based food for special medical purposes as therapy adjuvant for patients with HCV infection

OBJECTIVE

The present study aimed to develop a food for special medical purposes (FSMP) and to assess its efficacy as adjuvant therapy in patients with chronic hepatitis C virus (HCV).

DESIGN

Open randomized clinical trials with a tomato-based FSMP used as adjuvant treatment to the pharmacological therapy with pegilated interferon and ribavirin.

SUBJECTS

Eight healthy volunteers and 39 HCV patients.

INTERVENTIONS

For the bioavailability study, healthy subjects consumed 100 g/die FSMP for a week and their serum carotenoid profile at baseline, after the week of administration and 7 days later was determined. The same quantity of FSMP for 6 months by 20 of the 39 HCV patients was consumed in the clinical trial. Serum transaminase, haemoglobin (Hb) and hydroperoxide concentrations during the therapy were monitored in all patients.

RESULTS

FSMP consumption caused a fourfold increase of lycopene serum concentration in healthy subjects. A significant increase of carotenoids after 1 month of consumption also in patients with HCV was recorded. Transaminase and Hb serum levels, as well as therapeutic response, were not influenced by FSMP. The decrease in serum hydroperoxides was independent from FSMP consumption in long-term responder patients, whereas nonresponder (NR) patients of FSMP group showed higher reductions than NR patients of Control group.

CONCLUSIONS

The FSMP was effective in improving carotenoid status in healthy subjects. In HCV patients, it did not influence the therapeutic response, but it prevented carotenoid serum depletion and it was effective in improving the oxidative status during antiviral therapy in NR patients.

Apple polyphenol extracts prevent damage to human gastric epithelial cells in vitro and to rat gastric mucosa in vivo

BACKGROUND

Fresh fruit and vegetables exert multiple biological effects on the gastrointestinal mucosa.

AIM

To assess whether apple extracts counteract oxidative or indomethacin induced damage to gastric epithelial cells in vitro and to rat gastric mucosa in vivo.

METHODS

Apple extracts were obtained from freeze dried apple flesh of the "Annurca" variety. Cell damage was induced by incubating MKN 28 cells with xanthine-xanthine oxidase or indomethacin and quantitated by MTT. In vivo gastric damage was induced by indomethacin 35 mg/kg. Intracellular antioxidant activity was determined using the (2,2'-azinobis (3-ethylbenzothiazolin-6-sulfonate) method. Malondialdehyde intracellular concentration, an index of lipid peroxidation, was determined by high pressure liquid chromatography with fluorometric detection.

RESULTS

(1) Apple extracts decreased xanthine-xanthine oxidase or indomethacin induced injury to gastric epithelial cells by 50%; (2) catechin or chlorogenic acid (the main phenolic components of apple extracts) were equally effective as apple extracts in preventing oxidative injury to gastric cells; and (3) apple extracts (i) caused a fourfold increase in intracellular antioxidant activity, (ii) prevented its decrease induced by xanthine-xanthine oxidase, (iii) counteracted xanthine-xanthine oxidase induced lipid peroxidation, and (iv) decreased indomethacin injury to the rat gastric mucosa by 40%.

CONCLUSIONS

Apple extracts prevent exogenous damage to human gastric epithelial cells in vitro and to the rat gastric mucosa in vivo. This effect seems to be associated with the antioxidant activity of apple phenolic compounds. A diet rich in apple antioxidants might exert a beneficial effect in the prevention of gastric diseases related to generation of reactive oxygen species.

Use of antioxidants to minimize the human health risk associated to mutagenic/carcinogenic heterocyclic amines in food

Heterocyclic amines (HAs) are mutagenic/carcinogenic compounds formed in meat during cooking. Several efforts have been made to minimize the risk associated to HA human exposure. Supplementation with antioxidants is considered a promising measure to reduce HA exposure because of their ability as inhibitors of HA formation or as blocking/suppressing agents on HA biotransformation/metabolism. The aim of this review is to present the current knowledge on the capability of synthetic and natural antioxidants to modulate HA-induced mutagenicity/carcinogenicity. Data show a general trend towards a reduction of HA formation both in model systems and in real foods as well as an effective modulation of biotransformation and metabolism. Phenolic compounds, particularly those from tea and olive oil, seem to be the most effective, although a great variability is observed because of the concentration-dependent pro- and antioxidant effects.

Glycoalkaloids and acclimation capacity of hybrids between Solanum tuberosum and the incongruent hardy species Solanum commersonii

F(1) and backcross hybrids between sexually incompatible species Solanum commersonii and Solanum tuberosum were characterized for glycoalkaloid content and capacity to cold acclimate. Glycoalkaloid (GA) analysis revealed that F(1) triploids and BC(1) pentaploids contained the glycoalkaloids of both parents. In BC(2) (near) tetraploids the situation was different, in that some hybrids produced the GAs of both parents, whereas others contained only the GAs of S. tuberosum. This suggested that the GAs from S. commersonii may be lost rapidly, and that they may have a simple genetic control. The total tuber GA content of BC(1) and BC(2) groups averaged quite acceptable levels (165.9 mg/kg in BC(1) and 192.8 mg/kg in BC(2)), with six genotypes having a GA content <200 mg/kg fresh weight. The F(1) triploid hybrids expressed a capacity to cold acclimate similar to S. commersonii, whereas BC(1) and BC(2) genotypes generally displayed an acclimation capacity higher than the sensitive parent but lower than S. commersonii. However, one BC(1) and two BC(2) genotypes with an acclimation capacity as high as S. commersonii were identified. The polar lipid fatty acid composition in S. commersonii and its hybrid derivatives showed that, following acclimation, there was a significant increase in 18:3. Correlation analysis between the capacity to cold acclimate and the increase in 18:3 was significant, suggesting that the increase in 18:3 can be used as a biochemical marker for the assisted selection of cold-acclimating genotypes in segregating populations.

Influence of antioxidants in virgin olive oil on the formation of heterocyclic amines in fried beefburgers

An association between the intake of heterocyclic amines (HAs) and the development of cancer has been observed in some epidemiological studies, while in other studies no such correlation has been found. HAs are mutagenic/carcinogenic compounds formed at low levels via the Maillard reaction and a free radical mechanism during cooking of animal tissue. The addition of pure antioxidants or foods containing antioxidants has previously been shown to decrease the amount of HAs formed during cooking. In this study, beefburgers were fried in six different oils: refined olive oil, virgin olive oil, virgin olive oil depleted of phenols, rapeseed oil, virgin olive oil with rosemary extract and refined olive oil with rosemary extract. The content of antioxidative compounds in the virgin olive oil and the rosemary extract was determined. The beefburgers were analysed with regards to 12 different HAs by solid phase extraction and HPLC analysis. MeIQx, 4,8-DiMeIQx, PhIP, Harman and Norharman were detected in all beefburgers fried in the different oils, but the relative amounts varied. Frying in virgin olive oil reduced the formation of HAs compared with refined olive oil. This effect is probably due to the content of phenols in the virgin olive oil. The HA-reducing effect of virgin olive oil decreased during storage, but the addition of rosemary extract may prevent this decrease.

Characterization of coloured compounds obtained by enzymatic extraction of bakery products

Melanoidins, the brown-colored polymers formed through Maillard type reaction in several heat-treated foods, represent a significant part of our diet, with an average intake of grams per day. Most of the studies on the physiological effects of these compounds have been performed using the water soluble melanoidin fractions. But dietary melanoidins formed on the surface of bakery products are poorly soluble in water as well as in organic solvents. In this work, an enzymatic solubilization procedure was developed on a gluten-glucose model system and it was applied to bread and biscuits. The soluble material obtained was tested for its antioxidant activity, for its effect on phase-I and phase-II xenobiotic enzymes and for potential cytotoxic effects. Soluble melanoidins from model system and biscuits exhibit a strong antioxidant activity and do not show any cytotoxicity on Caco-2 cells. Melanoidins extracted from biscuits was able to inhibit the activity of Phase I (NADPH-cytochrome-c reductase) and Phase II (Glutathione-S-transferase) enzymes, whereas the low molecular weight melanoidins isolated from gluten-glucose model system inhibit the activity of NADPH-cytochrome-c reductase.

Moderate coffee consumption increases plasma glutathione but not homocysteine in healthy subjects

BACKGROUND

The consumption of unfiltered coffee, containing bioactive diterpenes, causes an increase in plasma homocysteine concentration. A slight increase in plasma homocysteine is also caused by large quantities of filtered coffee. Coffee terpenes also raise plasma glutathione in mice.

AIM

To verify the effect of Italian-style coffee consumption on the plasma concentration of glutathione and homocysteine in healthy subjects.

METHODS

Twenty-two volunteers consumed five cups of coffee per day for 1 week and maintained their usual diet. Five subjects were enrolled as controls. The intervention trial was preceded and followed by seven coffee-free days.

RESULTS

Plasma glutathione increased by 16% (P < 0.05) on coffee consumption, and returned to the original concentration after the washout period. The increase in plasma homocysteine concentration (13% after 1 week of coffee intake) was not significant. No differences in glutathione or homocysteine concentration were observed in the control group. No variation of plasma hydroperoxide concentration was detectable.

CONCLUSIONS

A coffee intake regimen, representing the average consumption of coffee drinkers in Italy, increased the plasma concentration of glutathione, but no significant increase in the plasma homocysteine concentration was detected.

The phytotoxic lipodepsipeptide syringopeptin 25A from Pseudomonas syringae pv syringae forms ion channels in sugar beet vacuoles

Syringopeptin 25A (SP(25)A) belongs to a family of cyclic lipodepsipeptides (LDPs) produced by the gram-negative bacterium Pseudomonas syringae, a phytopathogenic organism that affects several plants of agronomic interest. LDPs increase the permeability of plasma and, possibly, intracellular membranes in plant cells. Consistently, SP(25)A forms ion channels in planar lipid bilayers and other model membranes. Here we used sugar beet tonoplasts as a new biological model system to study toxin action. When applied to the vacuoles by a fast perfusion procedure, SP(25)A increases membrane permeability by forming discrete ion channels even at low applied potentials. The SP(25)A channel displays anion selectivity (with a Cl-/K+ permeability ratio of 6.7 +/- 1.3) and has intrinsic rectification properties that derive from a different channel conductance at negative and positive voltages, presumably owing to an asymmetric distribution of fixed charges on the pore. Substitution of chloride with different anions reveals the following selectivity sequence NO3- approximately Cl-> F- > gluconate-, suggesting that the permeation pore is filled with water. The properties of the SP(25)A channels in vacuolar membranes are similar to those observed in planar lipid membranes prepared with asolectin. This work provides a direct demonstration of toxin effects on a native plant membrane, extending to a biological system previous results obtained on artificial planar lipid membranes.

Characterization of phenolic compounds in virgin olive oil and their effect on the formation of carcinogenic/mutagenic heterocyclic amines in a model system

Mutagenic heterocyclic amines (HAs) are formed at low levels during cooking of meat and fish, and some of them are considered to be possible human carcinogens. The formation of HAs may be affected by the presence of synthetic or naturally occurring antioxidants. In the present study the effect of virgin olive oil (VOO) phenolic compounds, identified and quantified by LC-MS, on the formation of HAs in a model system was evaluated. An aqueous solution of creatinine, glucose, and glycine was heated in the presence of two samples of VOO differing only in the composition of phenolic compounds. The addition of VOO to the model system inhibited the formation of 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) by between 30 and 50% compared with the control. Fresh-made olive oil, which contained a high amount of dihydroxyphenylethanol derivatives, inhibited HA formation more than a 1-year-old oil did. The inhibition of HA formation was also verified using phenolic compounds extracted from VOO.

Analysis of bacterial lipodepsipeptides by matrix-assisted laser desorption/ionisation time-of-flight and high-performance liquid chromatography with electrospray mass spectrometry

Strains of certain plant pathogenic bacteria, in particular several pathovars of Pseudomonas syringae, are known to produce cyclic lipodepsipeptides (LDPs) endowed with peculiar structural features and noticeable biological activities. In this study, a mass spectrometry procedure is proposed for screening LDP-producing bacterial strains and for identifying and assessing individual LDPs. After matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) screening of thirteen P. syringae strains for LDP production, the extracts from culture filtrates of eight positive strains were subjected to electrospray mass spectrometry for the identification of LDPs. Five strains were found to produce two forms of syringomycins (SR-E and SR-G) and two forms of syringopeptin 25 (SP25A and SP25B); two strains produced SR-E, SR-G and a new form of SP22; one strain produced syringotoxin (ST) and syringostatin A (SS-A) in addition to SP25A and SP25B. The yield in culture of two major LPDs: SR-G (3.2-13.8 mg x L(-1)) and SP25A (41.6-231.5 mg x L(-1)) was assessed by and high-performance liquid chromatography with electrospray mass spectrometry (HPLC/ESI-MS) in both scan and single ion monitoring (SIM) modes. Results of this investigation showed that the mass spectrometry protocol developed here is a precise and reliable method for screening bacterial strains for LDP production and for assessing the amount of each metabolite under various culture conditions. This could be of practical value in view of potential applications, e.g. biocontrol of post-harvest fungal diseases.

Antioxidative activity and carotenoid and tomatine contents in different typologies of fresh consumption tomatoes

The phytonutrient intake associated with tomato consumption depends also on cultivar and fruit ripening stage. This work associates the antioxidative ability, the level of carotenoids, and the amount of glycoalkaloids to the main carpometric characteristics of four different typologies of tomatoes: "cherry", "cluster", "elongated," and "salad". These typologies have different weights and shapes, and they are usually consumed in the Mediterranean area at different ripening stages. Results showed that the considered tomato typologies also differ in their antioxidative ability and their carotenoid and glycoalkaloid contents. Growing conditions are also important in determining fruit characteristics: the analysis of the same cultivar of cherry tomato produced under the influence of moderate salt stress showed increases in the lipophilic antioxidative ability and the amount of carotenoid, whereas the level of glycoalkaloid decreased.

Simultaneous determination of beauvericin, enniatins, and fusaproliferin by high performance liquid chromatography

A rapid, sensitive and inexpensive HPLC method for routine screening of beauvericin, fusaproliferin, and enniatin B(1), A(1), and B has been optimized. Detection limits were determined, ranging between 0. 5 and 3.6 ng according to the compound obtained after spiking samples with each mycotoxin at 10-56 microg/mL concentration range; recoveries averaging from 56 to 74% were obtained. LC-MS conditions for enniatin analyses by API electrospray technique were set up, this allowing a unique identification of three different enniatins.

Antioxidant activity and general fruit characteristics in different ecotypes of Corbarini small tomatoes

Sixteen ecotypes of Corbarini small tomatoes were studied. The antioxidant activity was evaluated with the DMPD (N, N-dimethyl-p-phenylenediamine) method in the water-soluble fraction (S-AA) and with the ABTS [2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] method in the water-insoluble fraction (I-AA). S-AA and I-AA were strongly related to each other, varying to a large extent between the ecotypes considered. They were also significantly correlated with fruit weight, total solids, and refractive index. The combination of the latter variables (by multiple regression analysis) accounted for 36% and 44% of the total variability of S-AA and I-AA, respectively. Moreover, when the ecotypes were subdivided according to their shape (round, pear-shaped, oval, and long), S-AA and I-AA were both significantly higher in round tomatoes and lower in the long ones. In conclusion, the antioxidant activity varies to a considerable extent between different ecotypes of Corbarini small tomatoes. These differences are related to shape and some other fruit characteristics.

A comparison of color formation and maillard reaction products of a lactose-lysine and lactose-N(alpha)-acetyllysine model system

The formation of color and Maillard reaction products in two model systems consisting of lactose and lysine or N(alpha)-acetyllysine has been investigated. During heating, the blockage of the N(alpha) group of lysine determined a faster color and antioxidative ability development compared to the system with free lysine. This is combined to a greater amount of melanoidin formation in the acetylated lysine system, while in the free lysine system a higher amount of pyrraline and hydroxymethyl furfural were detected. The pattern of low molecular weight products suggests that 3-deoxyglucosone and 1-deoxyglucosone degradation pathways are favored for free lysine and N(alpha)-acetyllysine, respectively. Whole data allow us to hypothesize that in a lactose-N(alpha)-acetyllysine model system the formation of colored high molecular weight polymer proceeds faster because less material is dispersed in reaction pathways, mainly the Strecker degradation, which leads to small and intermediate molecular weight products.

Development of a stable isotope dilution assay for an accurate quantification of protein-bound N(epsilon)-(1-deoxy-D-fructos-1-yl)-L-lysine using a (13)C-labeled internal standard

Syntheses of the labeled Amadori compound [(13)C(6)]-N(epsilon)-(1-deoxy-D-fructos-1-yl)-L-lysine ([(13)C(6)]-DFLys) and the labeled glycated tetrapeptide Ala-[(13)C(6)]-DFLys-Leu-Gly are presented. The compounds were used in the development of stable isotope dilution assays for the quantification of the degree of glycosylation of bovine serum albumin treated for 20 min at 95 degrees C in the presence of glucose. The experiments revealed that the use of the labeled standards in combination with LC/MS allowed the exact quantification of protein-bound DFLys with the high recovery rate of 95% (at a spike level of 150 nmol/mg of protein) and a low detection limit of 5 nmol/mg of protein. The data revealed, however, that DFLys is significantly degraded during the enzymic hydrolysis of the protein backbone generally needed in the quantification procedure and, furthermore, incomplete digestion of the protein was observed. Both sources of errors were clearly overcome by using in particular the labeled peptide as the internal standard.

Extraction of azadirachtin A from neem seed kernels by supercritical fluid and its evaluation by HPLC and LC/MS

A new supercritical extraction methodology was applied to extract azadirachtin A (AZA-A) from neem seed kernels. Supercritical and liquid carbon dioxide (CO(2)) were used as extractive agents in a three-separation-stage supercritical pilot plant. Subcritical conditions were tested too. Comparisons were carried out by calculating the efficiency of the pilot plant with respect to the milligrams per kilogram of seeds (ms/mo) of AZA-A extracted. The most convenient extraction was gained using an ms/mo ratio of 119 rather than 64. For supercritical extraction, a separation of cuticular waxes from oil was set up in the pilot plant. HPLC and electrospray mass spectroscopy were used to monitor the yield of AZA-A extraction.

Convenient synthesis of lactuloselysine and its use for LC-MS analysis in milk-like model systems

The synthesis of the Amadori product lactuloselysine [N(epsilon)-(1-deoxy-D-lactulosyl-1)-L-lysine] was obtained starting from FMOC-lysine-OH (N(alpha)-9-fluorenylmethoxy-carbonyl-N(epsilon)H(2)-L-lysine-OH) and lactose. Compound identity was confirmed by MALDI-ToF, electrospray, and NMR analysis. A selective LC-MS procedure which allowed the detection of lactuloselysine up to 10 ng mL(-)(1) was set up and used to follow the formation of the compound in a lactose-lysine model system; quantification of this molecule after complete enzymatic hydrolysis of whey-proteins from milk samples was also performed.

LC/MS analysis and antioxidative efficiency of Maillard reaction products from a lactose-lysine model system

Aqueous solutions of lactose and lysine were refluxed for up to 4 h without pH control. Samples were collected every hour, and the reaction was monitored by measuring the pH, the optical density at 420 nm, and the relative antioxidative efficiency (RAE). The greatest change in optical density and antioxidative efficiency occurred for the mixture heated for 4 h. The 4 h solution was separated into three fractions according to the molecular weights of the components and tested for RAE. The high molecular weight fraction was more colored, and it had the highest antioxidative activity. The low molecular weight fraction was separated by high-performance liquid chromatography (HPLC). RAE values were measured for each purified compound. HPLC coupled with diode array and electrospray mass spectrometry allowed a rapid screening of the solutions and a tentative identification of several peaks. Nuclear magnetic resonance analysis allowed the identification of galactosylisomaltol and pyrraline. The resonance assignments for these compounds were revised.

Method for measuring antioxidant activity and its application to monitoring the antioxidant capacity of wines

A novel method for measuring the antioxidant activity using N, N-dimethyl-p-phenylenediamine (DMPD) was developed. The radical cation of this compound gives a stable colored solution and a linear inhibition of color formation can be observed in the presence of 0. 2-11 microg of TROLOX. The experimental protocol, which is rapid and inexpensive, ensures sensitivity and reproducibility in the measure of antioxidant activity of hydrophilic compounds. The effectiveness of the DMPD method on real foods was verified by evaluating the antioxidant ability of wine samples coming from different areas of Campania, Italy. Antioxidant capacity of wines is strictly related to the amount of phenolic compounds. The results obtained by the DMPD method are very similar to those obtained on the same samples when the radical cation of 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (Miller et al., 1996) was used.

Polyclonal antibodies against fusaproliferin

Fusaproliferin (FP), a toxic metabolite of the world-wide maize pathogens Fusarium proliferatum and Fusarium subglutinans, was recently found to be a natural contaminant of maize. Its toxic activity on haematopoietic human cell lines and its teratogenic effects on chicken embryos has been recently proved. Therefore a sensitive, rapid, and inexpensive screening test to detect FP in agricultural commodities is necessary to protect human health. FP-hemiglutarate conjugated to modified bovine serum albumin was synthesized, characterized, and used as an antigen for raising polyclonal antibodies by immunizing rabbits. Indirect and competitive ELISA and immunoblotting analyses were performed to determine antibody specificity towards the mycotoxin. The determination of 10 micrograms of free FP/mL was achieved using antibodies purified by means of affinity chromatography on a FP-lysine-Sepharose column. This unsatisfactory detection limit is due to high background values; thus, this method is not competitive with traditional UV-HPLC methods.

Identification of a beta-lactoglobulin lactosylation site

Thermal treatment of milk leads to non-enzymatic glycosylation of proteins through Maillard reaction. Free NH2 groups of basic amino acids react with the reducing carbonyl group of lactose forming the so-called Amadori products. Electrospray mass spectrometry analysis shows that beta-lactoglobulin (beta-LG), the major whey protein, undergoes lactosylation under industrial thermal treatment. In order to investigate the specificity of reactive sites for lactose binding the analysis of trypsin hydrolysates of beta-LG isolated from different industrial milks was performed. Results demonstrate that Lys-100 is a preferential lactosylation site of beta-LG during industrial milk treatment. These results were confirmed by an analysis of the three-dimensional model of the protein which showed that Lys-100 had the highest solvent accessibility and proximity to another amino group making Lys-100 the best candidate to lactosylation. Lys-47, previously identified by other authors, showed a good proximity to another Lys residue, but an intermediate level of exposition to solvent.

Fusicoccin effect on the in vitro interaction between plant 14-3-3 proteins and plasma membrane H+-ATPase

A 17-amino acid peptide was selectively cleaved from the highly variant C terminus of the 33-kDa 14-3-3 isoform occurring in fusicoccin receptor preparations from maize and was sequenced. The determined C-terminal sequence was identical to that of the already known maize 14-3-3 homolog GF14-6, thus prompting the use of recombinant GF14-6 in an in vitro protein-protein interaction study. The cDNA of GF14-6 was expressed in Escherichia coli as a 32P-phosphorylatable glutathione S-transferase fusion protein and was used as a probe in overlay experiments with H+-ATPase partially purified from maize roots. The results demonstrated that the recombinant protein specifically bound to H+-ATPase. The binding was dependent on Mg2+ and was strongly increased by fusicoccin. Controlled trypsin digestion of H+-ATPase abolished the association with GF14-6, a finding that was suggestive of an interaction with the C terminus of the enzyme. To confirm this result, the C-terminal domain of H+-ATPase was expressed as a glutathione S-transferase fusion peptide and was used in overlay experiments. GF14-6 was also able to bind to the isolated C terminus, but only in the presence of fusicoccin.

Fusaproliferin production by Fusarium subglutinans and its toxicity to Artemia salina, SF-9 insect cells, and IARC/LCL 171 human B lymphocytes

Fusarium subglutinans is an important pathogen of maize and other commodities worldwide. We examined MRC-115 and 71 other F. subglutinans strains from various geographic areas for their ability to synthesize fusaproliferin, a novel toxic sesterterpene recently isolated from F. proliferatum. Fusaproliferin production ranged from 30 to 1,500 micrograms/g of dried ground substrate, with 33 strains producing more than 500 micrograms/g. In particular, strain MRC-115 produced as much as 1,100 to 1,300 micrograms/g. In toxicity studies of two invertebrate models, fusaproliferin was toxic to Artemia salina (50% lethal dose, 53.4 microM) and to the lepidopteran cell line SF-9 (50% cytotoxic concentration, approximately 70 microM, after a 48-h exposure). Fusaproliferin was also toxic to the human nonneoplastic B-lymphocyte cell line IARC/LCL 171 (50% cytotoxic concentration, approximately 55 microM in culture in stationary phase after a 48-h exposure). Experiments performed will cells exposed at seeding suggested a possible cytostatic effect at subtoxic concentrations.

The H+-ATPase purified from maize root plasma membranes retains fusicoccin in vivo activation

The activity of 'P-type' ATPases is modulated through the C-terminal autoinhibitory domain. The molecular bases of the regulation are unknown. Their understanding demands functional and structural studies on the activated purified enzyme. In this paper the plasma membrane H+-ATPase from maize roots activated in vivo by fusicoccin was solubilised and fractionated by anion-exchange HPLC. Results showed that the H+-ATPase separated from fusicoccin receptors retained fusicoccin activation and that it was more evident after enzyme insertion into liposomes. These data suggest that fusicoccin stimulation does not depend on a direct action of the fusicoccin receptor on the H+-ATPase, but rather, fusicoccin brings about a permanent modification of the H+-ATPase which very likely represents a general regulatory mechanism for 'P-type' ATPases.

Structure and absolute stereochemistry of fusaproliferin, a toxic metabolite from Fusarium proliferatum

Fusaproliferin is a toxic sesterterpene isolated from Fusarium proliferatum, a widespread pathogen of cereals. Its absolute configuration has been determined by single crystal X-ray diffraction analysis. Fusaproliferin is considered to be a sesterterpene with a new ring skeleton having four C = C double bonds and four chiral atoms. The configurations of the four chiral atoms C10, C14, C15, and C19 are (R), (S), (R), and (S), respectively. In the solid state the macrolide shows a concave hydrophobic surface and hydrophilic convex face. The absolute configuration of C14 and C15 is the same as that observed for retigeranic acid, consistent with fusaproliferin being formed via a sesterterpenic-type biosynthetic pathway.

Paracelsin E, a new peptaibol from Trichoderma saturnisporum

The structure of paracelsin E, a new peptaibol from Trichoderma saturnisporum, has been determined primarily by fabms. The well-known paracelsins A, B, C, and D were also found in a culture of this organism.

Production of neosolaniol by Fusarium tumidum

Extracts from autoclaved maize culture of Fusarium tumidum strain R-5823 were toxic towards Artemia salina. Bioassay-guided fractionation of the organic extract led to the isolation of the toxic compound that was identified as the trichothecene toxin neosolaniol (NEOS) by 1H, 13C nuclear magnetic resonance spectroscopy and low-resolution electronic impact mass spectrometry. The amount of NEOS produced by the strain R-5823 was 300 mg/kg maize culture. NEOS was also detected by HPLC in cultures of four out of seven additional strains of F. tumidum and Gibberella tumida with different origin, in amounts ranging from 1 to 311 mg/kg. This is the first report on the production of a trichothecene toxin by F. tumidum.

The fungal H(+)-ATPase from Neurospora crassa reconstituted with fusicoccin receptors senses fusicoccin signal

Fusicoccin affects several physiological processes regulated by the plasma membrane H(+)-ATPase in higher plants while other organisms having P-type H(+)-ATPases (e.g., fungi) are fusicoccin-insensitive. We have previously shown that fusicoccin binding to its receptor is necessary for H(+)-ATPase stimulation and have achieved the functional reconstitution into liposomes of fusicoccin receptors and the H(+)-ATPase from maize. In this paper we show that fusicoccin sensitivity can be conferred on the H(+)-ATPase from Neurospora crassa, a fungus insensitive to fusicoccin. In fact, H+ pumping by purified H(+)-ATPase from Neurospora crassa reconstituted into liposomes containing crude or partially purified fusicoccin receptors from maize was markedly enhanced by fusicoccin. The stimulation of H+ pumping by fusicoccin is dependent upon pH, fusicoccin, and protein concentration, as was reported for the system reconstituted with both proteins from maize.