Release of lipids during yeast autolysis in a model wine system

The release of lipids during the aging of sparkling wines in contact with yeast can influence wine sensory attributes and, especially, foam characteristics. Model systems allow study of the autolysis process in a reasonable period of time compared to natural conditions, at which it can last several months. In this paper, the release of the different classes of lipids during the autolysis of three commercial yeast strains in a model wine medium has been monitored. Due to the absence of accurate quantitative methods, an HPLC method for separating and quantifying the different neutral and polar yeast lipid classes was developed. Lipids were eluted through a YMC PVA-Sil column with a complex solvent mixture. Detection was carried out with a light-scattering detector. The yeasts were suspended in the model wine buffer and incubated at 30 degrees C for up to 12 days. A release of triacylglycerols, 1,3-diacylglycerols, 2-monoacylglycerols, free fatty acids, sterol esters, and sterols was observed over the first 2 days, a period that corresponded to the maximum loss of yeast viability. A decrease in most of these lipids was observed from day 2, possibly indicative of the release of yeast hydrolytic enzymes due to the breakdown of the cell wall. Phospholipids were not detected in any of the autolysates. The mean lipid content in the autolysates as a percentage of the total lipid content in the yeasts was 8.6% for sterol esters, 3.8% for sterols, 2% for triacylglycerols, and <2% for 1,3-diacylglycerols and free fatty acids.

Acute arsenic poisoning: clinical and histopathological features

We report a woman with acute arsenic poisoning, who developed an erythroderma with vesicles and pustules after the ingestion of 8-16 g of sodium arsenite. Simultaneously, she presented a herpes simplex virus infection. Skin biopsies showed unique features which included multiple small pigment granules inside and outside the histiocytes. In our opinion, these findings are consistent with acute arsenic poisoning, and constitute the first histological description of this entity in skin.

Serum sickness-like syndrome due to mosquito bite

Local inflammatory reactions at the site of a mosquito bite are frequent. Immediate systemic reactions have occasionally been reported. The first case of a patient with relapsing episodes of a serum sickness-like syndrome following mosquito bites is reported herein. A 62-year-old patient came to the emergency room complaining of sudden malaise, chills, fever, headache, cervical lymph node enlargement, arthromyalgia, generalized purpura and leukopenia 6 h after a mosquito bite. He had experienced multiple similar episodes in the last 20 years, also following mosquito bites. Infectious and autoimmune diseases were ruled out. Serum IgE was 9,102 kU/l. Prick test of whole-body Culex pipiens extract was positive. Specific IgE to Aedes communis was 2.25 kU/l. SDS-PAGE immunoblotting of the patient's serum with whole-body C. pipiens extract revealed 43 and 17 kDa IgG-binding proteins and 22 and 17 kDa IgE-binding proteins, neither of which were found with control sera. Skin biopsy was consistent with leukocytoclastic vasculitis. The presence of both mosquito-specific IgE and IgG in the patient's serum suggest a possible cooperative immune response leading to clinical manifestations of serum sickness.

Anaphylactic reaction to ingestion of Quercus ilex acorn nut

BACKGROUND

A patient experienced an anaphylactic reaction after eating acorn nuts, fruit of the holm oak (Quercus ilex), one of the most abundant trees in Spain. Several urticaria episodes upon ingestion of peanuts were also referred.

OBJECTIVE

To assess the hypersensitivity reaction to acorn and to characterize the allergenic proteins involved.

METHODS

Cutaneous tests were performed using the skin-prick technique, using a large variety of grass, tree and weed pollens as well as fresh nuts and nut extracts. Specific IgE determination was assessed by RAST. IgE binding bands were determined by SDS-PAGE immunoblotting.

RESULTS

Skin-prick tests were strongly positive with acorn and peanut. Olea europaea, Quercus alba, Quercus ilex and grass pollens also elicited a weal higher than negative control. Patient serum had measurable levels of IgE antibodies especially to acorn, peanut and grass pollens. Only one protein band, of 17.9 kDa molecular mass, showed IgE-binding properties in the acorn extract. The possible homology of this strong allergenic protein with the group 1 tree pollen allergens was evidenced by the partial inhibition of the western blot with Bet v 1.

CONCLUSIONS

We present a case of anaphylaxis to acorn ingestion as demonstrated by in vivo and in vitro results. A 17.9 kDa IgE-binding band, showing some homology to group 1 pollen tree allergens, was recognized by patient serum.

[Outbreak of asthma caused by soybean dust allergy. Clinical and immunologic study of the affected patients]

BACKGROUND

To study the clinical and immunological data of patients affected by a soybean asthma outbreak in Tarragona, Spain.

PATIENTS AND METHODS

Characteristics of previous asthma, emergency rooms records and immediate outcome of 15 patients who attended emergency room departments the epidemic day were recorded. Functional respiratory studies, skin prick tests to aeroallergens, and prick tests, specific IgE and immunoblotting to soybean extracts were performed in all patients.

RESULTS

Thirteen patients were sensitized to soybean proteins. All of them were atopic (most sensitized to house dust mites) and half had started asthma symptoms after their thirties. The epidemic crisis was particularly severe in patients over 50 years, daily chronic asthma, severe obstructive pattern and/or non receiving steroids. Four patients were admitted to intensive care units. Seven patients showed asthma exacerbations (late reactions) 24 h after the beginning of the epidemic crisis. Specific IgE against a 5-6 kD and a 15.5-17 kD soybean proteins was detected in the sera of 8 patients and 10 patients, respectively.

CONCLUSIONS

The outbreak affected atopic patients exposed to soybean dust. The severity of the crisis was related with the previous severity of asthma. Besides the well known 5-6 kD allergenic soybean protein, the 15.5-17 kD protein seems also to be implicated in the sensitization of most of these patients.

Comparative allergenic study of Tetranychus urticae from different sources

Tetranychus urticae is a macroscopic mite known as "red spider mite". It is a cosmopolitan and polyphagous mite which parasitizes both fruit trees and herbaceous plants, particularly in greenhouses. Contribution of T. urticae to occupational asthma among greenhouse workers has been studied to identify and describe the main T. urticae allergens. In this study we described and compared the physiochemical characteristics of the main. T. urticae allergens from three different sources, carnation, cucumber and vegetable marrow. Forty-two green-house workers with occupational T. urticae allergy were included. Extracts were prepared from mite bodies collected from the three different sources; skin prick tests, specific IgE, SDS-PAGE and SDS-PAGE immunoblotting were carried out with the three T. urticae extracts. Cross-reactivity was measured by RAST inhibition. These assays were done with each of the three extracts in solid and fluid phases. All patients showed a positive prick test to T. urticae extracts from carnation, 39 (93%) to those from cucumber, and 34 (81%) to those from vegetable marrow. Specific IgE was positive in 80% of patient sera from T. urticae extract from carnation, 58% and 63% in that from cucumber and vegetable marrow, respectively. SDS-PAGE immunoblotting of the extracts showed coincident and relevant allergens. The similar curve obtained by RAST inhibition assays revealed the high epitope similarity from the three extracts. In conclusion, T. urticae extracts from parasitic carnation, cucumber and vegetable marrow cultures showed a high epitope similarity with three relevant allergens with molecular mass of 25, 19 and 15 to 17 kDa.

Sensitization to Zygophyllum fabago pollen. A clinical and immunologic study

Zygophyllum fabago is a herbaceous plant found widely in the Mediterranean area. There are no previous reports of its allergenicity. An aerobiologic and clinical survey was conducted in Murcia, southern Spain, to determine the quantity of airborne pollen and establish the possible role of this pollen as a cause of allergic symptoms. With a Hirst volumetric trap, we determined the atmospheric concentrations of this pollen in 1993, 1994, 1995, and 1996. Of 1180 patients tested, 181 (15.34%) had a positive skin test. To determine its allergenicity, we divided 47 patients into three groups: in group 1, all the patients had symptoms of rhinoconjunctivitis plus asthma; in groups 2 and 3, rhinoconjunctivitis. In group 1, we performed a bronchial provocation test (BPT); in groups 2 and 3, we performed nasal provocation (NPT) and conjunctival provocation (CPT) tests, respectively. SDS-PAGE was used to characterize the antigenic fractions and RAST inhibition to determine cross-reactivity with other pollens. The pollen dispersion period is from May to September (445 grains/m3). BPT was positive in 13 of 15 patients, NPT in 14 of 16 patients, and CPT in 13 of 16 patients. RAST inhibition revealed cross-reactivity with Mercurialis, Ricinus, Olea, and Betula. SDS-PAGE identified 25 IgE antibody-binding components, five of which (60, 65, 41, 38, and 15.5/14.7 kDa) were recognized by 40% of the sera. By SDS-PAGE immunoblotting with sunflower antiprofilin rabbit serum and affinity chromatography we established that the Z. fabago extract has profilin. This study shows that this pollen becomes airborne and elicits an IgE response which triggers respiratory symptoms in allergic subjects.

Sequence polymorphism and structural analysis of timothy grass pollen profilin allergen (Phl p 11)

Three cDNA clones encoding timothy grass pollen profilin (Phl p 11) were newly isolated. Comparison of the sequences of four cDNA clones, including a previously isolated clone, showed a low level of polymorphism. Isoelectrofocusing of highly purified timothy grass profilin indicated the existence of at least five isoforms. One recombinant profilin showed similar immunological properties to natural timothy grass profilin. Tertiary structure of Phleum pratense profilin was obtained by homology-based molecular modeling.

Allergens from Brazil nut: immunochemical characterization

The increase in the consumption of tropical nuts in the Northern Hemisphere during the last years, has evolved in a simultaneous enhancement of allergic IgE mediated (Hypersensitivity type 1) reported cases produced by this kind of food. The Brazil nut is the seed of the Bertholletia excelsa tree (Family Lecythidaceae) and, as in other seeds, proteins represent one of its major components making up 15-17% of its fresh weight and 50% of defatted flour. Of these, storage proteins are the most important ones, and the 12 S globulin legumin-like protein and the 2 S albumin have been described as the most representative. The 2 S protein, due to its high sulfur-rich amino acid content (3% cysteine and 18% methionine), is being studied, cloned and expressed in some important agronomic seeds (soybean, bean, oilseed rape) in order to enrich the nutritional quality of them. The case of a patient with serious clinical allergic symptoms (vomiting, diarrhoea and loss of consciousness) caused by oral contact with the Brazil nut, is presented. The patient gave a positive Skin Prick Test response to Brazil nut, kiwi and hazelnut extracts, and negative to regionally specific aeroallergens and other food extracts. The patient serum showed a high level of specific IgE by RAST to Brazil nut (> 17.5 PRU/ml, Class 4), and significative levels to hazelnut, and mustard. In vitro immunological studies (SDS-Immunoblotting and IEF-Immunoblotting) revealed IgE-binding proteins present in the extract. It was shown that not only the heavy (Mr 9) and light (Mr 4) subunits of the known allergenic 2 S albumin but also the alpha-subunits (Mr approximately 33.5 and 32) and at least one of the beta-subunits (Mr approximately 21) of the 12 S Brazil nut globulin, hitherto never involved in allergic problems, showed a strong IgE-binding capacity.

Mercurialis annua: characterization of main allergens and cross-reactivity with other species

A multicentric study was conducted to evaluate the frequency of Mercurialis annua pollen sensitization in several areas of Spain and to select a population sample to characterize the main allergenic components in M. annua pollen. Patients were recruited from six hospitals in Spain. Out of 420 patients sensitized to pollens, 195 (46.4%) showed positive skin tests to M. annua, thus evidencing the high level of sensitization to the pollen of this plant in Spain. Thirty-seven sera with RAST class values to M. annua > or = 3 were selected for SDS-PAGE immunoblotting analysis. Two main allergenic components with molecular weights of 15.8 and 14.1 kD were detected in 59 and 51% of the sera, respectively, and they were identified as profilins. Isolation of the relevant allergens was made by affinity chromatography on a poly-L-proline-Sepharose column, followed by gel filtration and anion exchange chromatography in the micropreparative SMARTs System. A significant but low antigenic cross-reactivity between M. annua and Olea europaea, Fraxinus elatior, Ricinus communis, Salsola kali, Parietaria judaica and Artemisia vulgaris was demonstrated by several in vitro techniques.

An Aspergillus niger esterase (ferulic acid esterase III) and a recombinant Pseudomonas fluorescens subsp. cellulosa esterase (Xy1D) release a 5-5' ferulic dehydrodimer (diferulic acid) from barley and wheat cell walls

Diferulate esters strengthen and cross-link primary plant cell walls and help to defend the plant from invading microbes. Phenolics also limit the degradation of plant cell walls by saprophytic microbes and by anaerobic microorganisms in the rumen. We show that incubation of wheat and barley cell walls with ferulic acid esterase from Aspergillus niger (FAE-III) or Pseudomonas fluorescens (Xy1D), together with either xylanase I from Aspergillus niger, Trichoderma viride xylanase, or xylanase from Pseudomonas fluorescens (XylA), leads to release of the ferulate dimer 5-5' diFA [(E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid]. Direct saponification of the cell walls without enzyme treatment released the following five identifiable ferulate dimers (in order of abundance): (Z)-beta-(4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy)-4-hydroxy-3-methoxycinnamic acid, trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxy-phenyl) -7-methoxy-2, 3-dihydrobenzofuran-3-carboxylic acid, 5-5' diFA, (E,E)-4, 4'-dihydroxy-3, 5'-dimethoxy-beta, 3'-bicinnamic acid, and trans-7-hydroxy-1-(4-hydroxy-3-methoxyphenyl) -6-methoxy-1, 2-dihydronaphthalene-2, 3-dicarboxylic acid. Incubation of the wheat or barley cell walls with xylanase, followed by saponification of the solubilized fraction, yielded 5-5'diFA and, in some cases, certain of the above dimers, depending on the xylanase used. These experiments demonstrate that FAE-III and XYLD specifically release only esters of 5-5'diFA from either xylanase-treated or insoluble fractions of cell walls, even though other esterified dimers were solubilized by preincubation with xylanase. It is also concluded that the esterified dimer content of the xylanase-solubilized fraction depends on the source of the xylanase.

Phenolic Inhibitors of α-Amylase and Trypsin Enzymes by Extracts From Pears, Lentils, and Cocoa

Inhibition of α-amylase and trypsin by phenolic extracts of various fruit and vegetable foodstuffs (pears [ Pyrus communis ], lentils [ Lens esculenta ], and cocoa beans [ Theobroma cacao ]) was studied. An appropriate methodology for determining the percentage of inhibition of each enzyme was developed. A concomitant study carried out using standard substances (gallic acid, (+)-catechin, tannic acid, and condensed tannins) showed that polymeric phenols were more potent inhibitors than the simple forms, all of them having different behaviors towards the enzymes, depending on their chemical characteristics. The inhibitory potency of the extracts varied according to the phenolic composition of each and was intermediate between that of the simple and that of the more complex phenolic compounds. Inhibition of α-amylase by the phenolic extracts (at equal concentrations) was of the same order of magnitude, even though the phenolic nature and content in the three foodstuffs differed substantially. In contrast, in the case of trypsin, the lentil and cocoa extracts displayed inhibition 10 times greater than that of the pear extract.

Sensitization to sunflower pollen: only an occupational allergy?

Sunflower (Helianthus annuus) pollen sensitization has been reported as an occupational allergy. In this report, the sensitization of the general population living in sunflower-growing areas to Helianthus pollen was studied. Both RAST results in 32 adults with summer symptoms previously diagnosed as allergic to Artemisia pollen, and cross-reactivity studies between H. annuus and other Compositae suggested that H. annuus pollen was the main allergen involved in the hypersensitivity reaction of those patients. Good correlation was found between RAST and SPT to Helianthus and between RAST and conjunctival provocation test to Helianthus. Bronchial challenge tests performed on 8 of the 32 patients confirmed the clinical implication of Helianthus pollen in suspected subjects. Five workers, handling sunflower pollen, who suffered from related symptoms were subjected to the same study, showing lesser wheal areas and lesser specific IgE levels than a non-worker group. Thirteen patients with RAST values > or = class 2 showed 2 IgE-binding fractions at 34.0 and 42.8 kD in 65% of sera and 3 IgE-binding fractions at pI 4.9, 9.6 and 10.2 in 54% of sera. By means of micropreparative high-resolution chromatography, it was possible to purify a 34-kD major allergen. Analysis performed by RAST inhibition with sera from atopic patients and ELISA inhibition with experimental anti-Helianthus rabbit sera demonstrated a cross-reactivity between Helianthus and other Compositae, but low affinity of specific anti-Helianthus antibodies for heterologous antigens. Taking into account the above-mentioned data, and the high prevalence of Helianthus pollen in the atmosphere during harvesting (in spite of its entomophilous character), Helianthus pollen should be considered as an allergenic source to be investigated in the general population living in sunflower-growing regions suffering from seasonal summer allergy.

Dander is the best epithelial source for dog allergenic extract preparations

Four different commercially available raw materials of dog epithelia (dander, hair and skin scraping, skin scraping, and whole skin) were compared by means of biochemical methods such as SDS-PAGE and chromatography with the SMART System, immunochemical methods such as RAST and SDS-PAGE immunoblotting, and cutaneous tests. Dander extract clearly exhibited the highest IgE binding and in vivo allergenic activity. The dog major allergens Can fI and the 19-kDa protein were adequately detected only in dander extract. Thus, it is concluded that dander is the most suitable epithelial source for preparing dog allergenic extracts.

Determination of patulin in apple juice by high-performance liquid chromatography with diode-array detection

A method is described for the detection of patulin in apple juice and the simultaneous determination of the phenolic composition. Spectral data obtained with diode-array detection showed that patulin can be easily distinguished from compounds eluting under the same conditions. The detection limit for patulin was 8.96 micrograms/l.

Release of lipid vesicle contents by the bacterial protein toxin alpha-haemolysin

alpha-Haemolysin is a protein toxin (107 kDa) secreted by some pathogenic strains of E. coli. It binds to mammalian cell membranes, disrupting cellular activities and lysing cells. This paper describes the mechanism of alpha-haemolysin-induced membrane leakage, from experiments in which extrusion large unilamellar vesicles, loaded with fluorescent solutes, are treated with purified toxin. The results show that the toxin does not require of any membrane receptor to exert its activity, that vesicles become leaky following an 'all-or-none' mechanism, and that leakage occurs through a non-osmotic detergent-like bilayer disruption induced by the protein. Small pores formed by monomeric alpha-haemolysin, as described by other authors, do not appear to be related to the process of membrane disruption. Instead, the experimental data would be in agreement with the idea of oligomeric assemblies being required to produce release of solutes from a single vesicle.

Construction and properties of a family of pACYC184-derived cloning vectors compatible with pBR322 and its derivatives

A family of cloning vectors derived from plasmid pACYC184 and, therefore, compatible with pBR322 and its derivatives (especially the pUC family of vectors), is described. They all contain a multiple cloning site (MCS) and the lacZ alpha reporter gene for easy cloning. They have been grouped in three sets: (i) six of the vectors contain a chloramphenicol-resistance (CmR)-encoding gene and each a different MCS with 16 unique restriction sites overall; (ii) another six vectors contain a kanamycin-resistance (KmR)-encoding gene and the same six MCS; and (iii) two CmR vectors that contain the SP6 and T7 promoters flanking the MCS and lacZ alpha reporter gene of pUC18/19.

Alpha-haemolysin from E. coli. Purification and self-aggregation properties

An improved, straightforward purification procedure for E.coli alpha-haemolysin has been developed. The protein exists in the form of large aggregates, held together mainly by hydrophobic forces. In the presence of urea or other chaotropic agents, the size of the aggregates decreases, while the specific activity is increased.

pACYC184-derived cloning vectors containing the multiple cloning site and lacZ alpha reporter gene of pUC8/9 and pUC18/19 plasmids

A new series of vectors, pSU2716, pSU2717, pSU2718, and pSU2719, has been constructed. The plasmids contain (i) the P15A replicon, (ii) the chloramphenicol acetyl transferase (CAT)-coding gene from Tn9, and (iii) the HaeII fragment which carries the multiple cloning site and the lacZ alpha reporter gene of pUC8, pUC9, pUC18 and pUC19, respectively. These vectors allow rapid and simple transfer of inserts from pUC plasmids, have an intermediate copy number (which allows regulated expression from the lac promoter), and are compatible with ColE1-derived vectors (and, therefore, can be used in studies requiring the joint expression of two genes, for example, in genetic complementation analysis). Furthermore, the accumulation of CAT instead of beta-lactamase, allows an easy visualization in sodium dodecyl sulfate-polyacrylamide-gel electrophoresis of proteins of 28-35 kDa, which can otherwise be obscured by the beta-lactamase.