Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “peach”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Peach fuzz contains large amounts of lipid transfer protein: is this the cause of the high prevalence of sensitization to LTP in Mediterranean countries?

BACKGROUND: Allergy to lipid transfer protein (LTP) is quite common in the Mediterranean countries but virtually absent in Northern Europe. The reasons for this latitude-dependent distribution are unclear. One hypothesis is that peach, the primary sensitizer to LTP, may lose in part its allergenicity as a consequence of treatments (handling, brushing, washing, and packaging) preceding marketing in Northern European. Peach surface fuzz might represent a potential vehicle of LTP. OBJECTIVE: To detect LTP in peach fuzz, and compare IgE reactivity to peach fuzz and peel of sera from LTP-allergic patients. METHODS: IgE reactivity to peach peel and peach fuzz extract was measured by ELISA using sera from 2 LTP-allergic PATIENTS. Purified peach LTP was used in inhibition studies. RESULTS: Both sera strongly reacted both to peach peel and fuzz but reactivity to fuzz was stronger than to peel. Pre-absorption of one serum with peach LTP caused an 87% reduction of IgE reactivity to peach fuzz extract. CONCLUSION: Peach fuzz contains large amounts of LTP and might be a potential vehicle of this allergen causing sensitization in genetically predisposed subjects. Fuzz loss during pre-marketing handling of peaches might be at the basis of the geographic differences that characterize allergy to LTP.

Antigens, Plant↗

Relationship between peach lipid transfer protein specific IgE levels and hypersensitivity to non-Rosaceae vegetable foods in patients allergic to lipid transfer protein.

BACKGROUND: Lipid transfer protein (LTP), the major allergen in Rosaceae in geographic areas where the prevalence of birch pollen allergy is low, is a widely cross-reacting pan-allergen, but the pattern of cross-reactivity to plant-derived foods botanically unrelated to Rosaceae shows much variability. OBJECTIVE: To examine the relationship between peach LTP specific IgE levels and cross-reactivity to several non-Rosaceae, plant-derived foods. METHODS: IgE specific for peach LTP was measured by enzyme-linked immunosorbent assay in serum samples from 40 patients with Rosaceae allergy monosensitized to LTP. Patients were considered monosensitized to this protein in the absence of sensitization to other cross-reacting, plant-derived foods as shown by negative skin prick test (SPT) results with both birch and mugwort pollen. SPTs with commercial extracts of walnut, hazelnut, peanut, celery, maize, rice, tomato, orange, and onion were performed to detect possible immunologic cross-reactivity to these foods. RESULTS: Patients with negative SPT results with non-Rosaceae foods showed significantly lower levels of IgE to peach LTP than patients showing skin reactivity to one or more non-Rosaceae foods (P < .001). A significant difference in specific IgE to peach LTP between patients with positive or negative SPT results was observed with each individual food (P < .001 in all cases). The level of IgE to peach LTP was strongly related to the number of positive SPT results with non-Rosaceae foods (r = 0.78; P < .001). Increasing levels of IgE to peach LTP were associated with skin reactivity to nuts (29/40 [72%]), peanut (27/40 [67%]), maize (16/39 [41%]), rice (14/39 [36%]), onion (13/37 [35%]), orange (9/32 [28%]), celery (11/40 [27%]), and tomato (8/39 [20%]). CONCLUSIONS: This study suggests that all allergenic determinants in LTP from vegetable foods other than peach cross-react with peach LTP determinants, whereas only some peach LTP epitopes cross-react with allergenic determinants on botanically unrelated, plant-derived foods. The high levels of IgE to peach LTP seem to reflect the presence of IgE targeting common allergenic determinants of LTP, causing cross-reactivity to botanically unrelated, vegetable foods. In LTP-allergic patients, increasing levels of IgE to peach LTP are paralleled by an increasing number of foods other than Rosaceae positive on SPT that cause clinical symptoms.

Antigens, Plant↗

Peach profilin: cloning, heterologous expression and cross-reactivity with Bet v 2.

BACKGROUND: Peach is among the main foods causing allergic reactions in the Mediterranean adult population. Only a single peach allergen, named Pru p 3, has been characterized. However, a potential role of profilin has also been suggested in grass pollen-associated allergy to peach. METHODS: Complementary DNA clones for two different peach profilin isoforms were obtained by reverse transcriptase polymerase chain reaction using non-degenerated primers. Expression of recombinant peach profilin was performed in Escherichia coli, and confirmed using rabbit polyclonal antibodies to sunflower pollen profilin. Twenty-nine individual sera from patients with peach allergy proved by double-blind, placebo-controlled food challenges (DBPCFC), either with (n = 15) or without (n = 14) specific IgE to Bet v 2, were used in immunodetection assays to test recombinant peach profilin reactivity. RESULTS: Each peach profilin cDNA included an open reading frame coding for a 131 amino acid protein. The peach profilin isoforms, designated Pru p 4.01 and Pru p 4.02, showed 80% of amino acid sequence identity, and were very similar (>70% identity) to allergenic profilins from plant foods and pollens. Recombinant Pru p 4.01 was expressed in E. coli as a nonfusion protein, displaying the expected molecular size and reacting with anti-profilin antibodies. rPru p 4.01 was recognized by all sera (15 of 15) with specific IgE to Bet v 2, whereas no sera (zero of 14) without IgE to this birch allergen reacted with rPru p 4.01. CONCLUSIONS: Peach profilin Pru p 4 is very closed to other allergenic profilins from plant foods and pollens. A complete correlation between reactivity to rPru p 4 and rBet v 2 has been found in sera from peach allergic patients.

Adolescent↗

Pru p 3 (LTP) content in peach extracts.

BACKGROUND: Lipid transfer proteins are molecules widely distributed in fruits. Sensitization to LTP is frequent in fruit sensitive patients. The aims of this study were to purify LTP and to assess the content of LTP in ripe peach peel and pulp extracts by ELISA inhibition using polyclonal antibodies. METHODS: LTP was purified from ripe yellow peach peel by two different column chromatography methods. A polyclonal antibody was produced by injecting purified LTP into two New Zealand white rabbits. ELISA inhibition and rabbit monospecific polyclonal antibody were used to calculate the LTP content in Springcrest and Miraflores varieties of peach peel and pulp extracts. Purified LTP (2.5 mg/ml) was used to skin test 24 peach-sensitive patients. RESULTS: The purified LTP showed a single band at approximately 9 kDa. The polyclonal antibody raised anti LTP recognized only the LTP molecule in the peach extracts. LTP content, expressed in micro g/mg of freeze-dried extract in four extracts were: yellow peach peel, 15.48; yellow peach pulp 2.25; red peach peel 14.67 and red peach pulp 1.84. Twenty patients (83.3%) had a positive skin test with purified LTP. CONCLUSIONS: We have developed a system to determine the concentration of LTP in peach extracts. LTP in peel extracts is approximately seven times greater than in pulp.

Allergens↗

Antioxidant capacities, phenolic compounds, carotenoids, and vitamin C contents of nectarine, peach, and plum cultivars from California.

Genotypic variation in composition and antioxidant activity was evaluated using 25 cultivars, 5 each of white-flesh nectarines, yellow-flesh nectarines, white-flesh peaches, yellow-flesh peaches, and plums, at the ripe (ready-to-eat) stage. The ranges of total ascorbic acid (vitamin C) (in mg/100 g of fresh weight) were 5-14 (white-flesh nectarines), 6-8 (yellow-flesh nectarines), 6-9 (white-flesh peaches), 4-13 (yellow-flesh peaches), and 3-10 (plums). Total carotenoids concentrations (in microg/100 g of fresh weight) were 7-14 (white-flesh nectarines), 80-186 (yellow-flesh nectarines), 7-20 (white-flesh peaches), 71-210 (yellow-flesh peaches), and 70-260 (plums). Total phenolics (in mg/100 g of fresh weight) were 14-102 (white-flesh nectarines), 18-54 (yellow-flesh nectarines), 28-111 (white-flesh peaches), 21-61 (yellow-flesh peaches), and 42-109 (plums). The contributions of phenolic compounds to antioxidant activity were much greater than those of vitamin C and carotenoids. There was a strong correlation (0.93-0.96) between total phenolics and antioxidant activity of nectarines, peaches, and plums.

Antioxidants↗

A method for quantitation of food biologic activity: results with peach allergen extracts.

OBJECTIVE: The aim of this study was to develop a quantitative skin test assay for measurement of the biologic activity of food allergen extracts, as well as to report the results obtained with a peach extract labeled in food biological units (FBUs). METHODS: We prepared a biologically quantified peach extract. The biologic activity was measured in FBUs by assigning 100 FBU/ml to the biologic activity of the extract that elicited a wheal area with a geometric mean equal to that produced by the prick-prick method by using the food itself in a population of 30 patients allergic to food. We evaluated 265 patients, including 70 patients allergic to peach and 195 control subjects (100 nonatopic subjects and 95 subjects allergic to pollen). The biologically quantified peach extract was used during the study and was compared with four commercial peach extracts, which were labeled in weight per volume. RESULTS: The sensitivity of the nonstandardized commercial peach extracts varied from 4.3% to 74%, with biologic activity being very low in all of them. The sensitivity of the biologically quantified peach extract was 100%, with a 100% concordance between the prick-prick and the skin prick test results. CONCLUSION: These data demonstrate that if peach allergen preparations were biologically standardized in FBUs, the quality of these food extracts used for diagnosis would be improved.

Adolescent↗

Pollen allergy in peach-allergic patients: sensitization and cross-reactivity to taxonomically unrelated pollens.

BACKGROUND: Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization. OBJECTIVE: The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them. METHODS: One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin. RESULTS: The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients. CONCLUSION: The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.

Adolescent↗

Technological processes to decrease the allergenicity of peach juice and nectar.

Among vegetable foods peach (Prunus persica) has been recognized as a significant cause of allergy. The protein, which is considered to be the major peach allergen, has been named Pru p 1. Because peaches are consumed both as fresh fruits and after processing to obtain peach juice, nectar, jam, syrupy peach, etc., research was carried out to identify a technological process for production of hypo- or nonallergenic peach-based products. SDS-PAGE and immunoblotting analysis of extracts prepared from four commercial peach nectars showed that the Pru p 1 was not removed, and neither was its allergenic activity decreased by technological treatments carried out for nectar production. Some treatments oriented toward a removal of or, at least, a decrease in the allergenic power were assumed and verified at laboratory scale. A variable considered was heat treatment at 121 degrees C for 10 and 30 min: this treatment was not able to decrease the allergenicity of the Pru p 1 protein. Furthermore, the protein band was still present even after 60-min reaction with two different acidic proteases. The two technological treatments that were found to decrease the major allergen of peach were chemical lye peeling of fruits and ultrafiltration of juice through membranes with suitable cutoff. On the basis of the results obtained from this research, a processing flow sheet was defined to obtain hypoallergenic or probably nonallergenic limpid juices and nectars. These products may represent, besides finished foods, intermediates to obtain various products after addition of further ingredients such as pectins, sugars, and fiber.

Beverages↗

Cloning and characterization of a non-TIR-NBS-LRR type disease resistance gene analogue from peach.

Cloning of plant disease resistant genes is greatly helpful for disease resistant breeding in plants and the insight of resistance mechanism. However, there are less relevant researches in peach [prunus persica (L.) Batch]. In this study, four NBS-LRR type resistance gene analogs (RGAs) were cloned from genomic DNA of peach. The PNBS2 fragment was also amplified from peach cDNA and the full-length cDNA of PNBS2 (PRPM1, GenBank accession no. AY599223) has been cloned. Sequence analysis indicated that the cDNA of PRPM1 is 3007 bp in length and that the contained ORF encodes for a polypeptide of 917 amino acids. Compared with known NBS-LRR genes, it presented relatively high amino acid sequence identity. The polypeptide has typical structure of non-TIR-NBS-LRR genes, with NB-ARC, LZ, LRR and transmembrane domains. Southern analysis indicated that the PRPM1 gene might be a single copy in peach genome. Northern blot and RT-PCR analysis showed that the expression of PRPM1 was not induced by salicylic acid (SA) in peach young leaves. The isolation of putative resistance genes from peach provided useful bases for studying the structure and function of peach disease-resistance relating genes and disease resistant genetic breeding in peach.

Amino Acid Sequence↗

Effects of a biocontrol agent and methyl jasmonate on postharvest diseases of peach fruit and the possible mechanisms involved.

AIMS: To investigate effects of application of 200 micromol l(-1) methyl jasmonate [MeJA (200)] and Cryptococcus laurentii alone or in combination against postharvest diseases (Monilinia fructicola and Penicillium expansum) in peach fruit stored at 25 and 0 degrees C, and to evaluate the possible mechanisms involved. METHODS AND RESULTS: The efficacy of controlling postharvest diseases by resistance induced in peach fruit treated with MeJA (200) and C. laurentii alone or in combination and the relationship between activities of defence-related enzymes in peach fruit and lesions caused by M. fructicola and P. expansum were examined. At the same time, the effects of MeJA (200) on the population of C. laurentii in the peach wounds and on the mycelial growth of M. fructicola and P. expansumin vitro were investigated. The results indicated that treatment of peach fruit with C. laurentii at 1 x 10(8) CFU ml(-1) alone, or combining C. laurentii at 5 x 10(7) CFU ml(-1) with MeJA (200) all resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum compared with the controls in peach fruit. MeJA (200) enhanced the population of C. laurentii, and inhibited mycelial growth of P. expansum. However, it had a little effect on M. fructicolain vitro. MeJA and C. laurentii alone or in combination induced higher activities of Chitinase, beta-1,3-glucanase, phenylalanine ammonia-lyase and peroxidase (POD) than applying the yeast alone at both 25 and 0 degrees C. CONCLUSIONS: MeJA (200) not only directly inhibited mycelial spread of postharvest pathogens, but also increased population of C. laurentii, which induced stronger disease resistance in fruit than MeJA or yeast alone, and resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum. SIGNIFICANCE AND IMPACT OF THE STUDY: MeJA (200) in combination with C. laurentii was beneficial for controlling brown rot and blue mould caused by M. fructicola and P. expansum in peach fruit. The inhibitory mechanism was mainly because of resistance induced in peach fruit by MeJA and C. laurentii. In addition, direct inhibition of MeJA on P. expansum also played a role in controlling blue mould.

Acetates↗

Candidate genes and QTLs for sugar and organic acid content in peach [ Prunus persica (L.) Batsch].

The identification of genes involved in variation of peach fruit quality would assist breeders in creating new cultivars with improved fruit quality. Major genes and quantitative trait loci (QTLs) for physical and chemical components of fruit quality have already been detected, based on the peach [ Prunus persica (L.) Batsch] cv. Ferjalou Jalousia((R)) (low-acid peach) x cv. Fantasia (normally-acid nectarine) F(2) intraspecific cross. Our aim was to associate these QTLs to structural genes using a candidate gene/QTL approach. Eighteen cDNAs encoding key proteins in soluble sugar and organic acid metabolic pathways as well as in cell expansion were isolated from peach fruit. A single-strand conformation polymorphism strategy based on specific cDNA-based primers was used to map the corresponding genes. Since no polymorphism could be detected in the Ferjalou Jalousia((R)) x Fantasia population, gene mapping was performed on the almond [ Prunus amygdalus ( P. dulcis)] cv. Texas x peach cv. Earlygold F(2) interspecific cross from which a saturated map was available. Twelve candidate genes were assigned to four linkage groups of the peach genome. In a second step, the previous QTL detection was enhanced by integrating anchor loci between the Ferjalou Jalousia((R)) x Fantasia and Texas x Earlygold maps and data from a third year of trait assessment on the Ferjalou Jalousia((R)) x Fantasia population. Comparative mapping allowed us to detect a candidate gene/QTL co-location. It involved a cDNA encoding a vacuolar H(+)-pyrophosphatase ( PRUpe;Vp2) that energises solute accumulation, and QTLs for sucrose and soluble solid content. This preliminary result may be the first step in the future development of marker-assisted selection for peach fruit sucrose and soluble solid content.

Journal Article↗

Microsatellite genetic linkage maps of myrobalan plum and an almond-peach hybrid--location of root-knot nematode resistance genes.

Inheritance and linkage studies were carried out with microsatellite [or simple sequence repeat (SSR)] markers in a F(1) progeny including 101 individuals of a cross between Myrobalan plum ( Prunus cerasifera Ehrh) clone P.2175 and the almond (Prunus dulcis Mill.)-peach ( Prunus persica L. Batsch) hybrid clone GN22 ["Garfi" (G) almond x "Nemared" (N) peach]. This three-way interspecific Prunus progeny was produced in order to associate high root-knot nematode (RKN) resistances from Myrobalan and peach with other favorable traits for Prunus rootstocks from plum, peach and almond. The RKN resistance genes, Ma from the Myrobalan plum clone P.2175 and R(MiaNem) from the 'N' peach, are each heterozygous in the parents P.2175 and GN22, respectively. Two hundred and seventy seven Prunus SSRs were tested for their polymorphism. One genetic map was constructed for each parent according to the "double pseudo-testcross" analysis model. The Ma gene and 93 markers [two sequence characterized amplified regions (SCARs), 91 SSRs] were placed on the P.2175 Myrobalan map covering 524.8 cM. The R(MiaNem) gene, the Gr gene controlling the color of peach leaves, and 166 markers (one SCAR, 165 SSRs) were mapped to seven linkage groups instead of the expected eight in Prunus. Markers belonging to groups 6 and 8 in previous maps formed a single group in the GN22 map. A reciprocal translocation, already reported in a G x N F(2), was detected near the Gr gene. By separating markers from linkage groups 6 and 8 from the GN22 map, it was possible to compare the eight homologous linkage groups between the two maps using the 68 SSR markers heterozygous in both parents (anchor loci). All but one of these 68 anchor markers are in the same order in the Myrobalan plum map and in the almond-peach map, as expected from the high level of synteny within Prunus. The Ma and R(MiaNem)genes confirmed their previous location in the Myrobalan linkage group 7 and in the GN22 linkage group 2, respectively. Using a GN22 F(2) progeny of 78 individuals, a microsatellite map of linkage group 2 was also constructed and provided additional evidence for the telomeric position of R(MiaNem) in group 2 of the Prunus genome.

Animals↗

Perceptual ratings for pureed and molded peaches for individuals with and without impaired swallowing.

Food molds have been created to alter the appearance of pureed foods by making the pureed consistencies look more like typically prepared foods. This study examined the perceptions of 15 adults with impaired swallowing and 15 adults with nonimpaired swallowing for three different types of pureed peach: a typically prepared pureed peach, a pureed peach with a thickening agent added, and a pureed peach with a thickening agent added and molded to look like peach slices. Results are presented for the attribute ratings of overall liking: liking of taste, texture, and appearance; and ease of chewing and swallowing. The results showed that the adults with impaired swallowing rated the attributes of chewing and swallowing significantly lower (i.e.. more difficult) for each type of puree. Significant differences within samples also were found for the attributes of overall liking and liking of taste. Overall, the pureed peach molds were not perceived favorably for any of the examined attributes. In addition, the molded peach was rated lower (more difficult) in its ease of chewing. The implications of these findings and ideas for further research are discussed.

Adult↗

Self-compatible peach (Prunus persica) has mutant versions of the S haplotypes found in self-incompatible Prunus species.

This study demonstrates that self-compatible (SC) peach has mutant versions of S haplotypes that are present in self-incompatible (SI) Prunus species. All three peach S haplotypes, S (1), S (2), and S (2m), found in this study encode mutated pollen determinants, SFB, while only S (2m) has a mutation that affects the function of the pistil determinant S-RNase. A cysteine residue in the C5 domain of the S (2m)-RNase is substituted by a tyrosine residue, thereby reducing RNase stability. The peach SFB mutations are similar to the SFB mutations found in SC haplotypes of sweet cherry (P. avium) and Japanese apricot (P. mume). SFB (1) of the S (1) haplotype, a mutant version of almond (P. dulcis) S (k) haplotype, encodes truncated SFB due to a 155 bp insertion. SFB (2) of the S (2) and S (2m) haplotypes, both of which are mutant versions of the S (a) haplotype in Japanese plum (P. salicina), encodes a truncated SFB due to a 5 bp insertion. Thus, regardless of the functionality of the pistil determinant, all three peach S haplotypes are SC haplotypes. Our finding that peach has mutant versions of S haplotypes that function in almond and Japanese plum, which are phylogenetically close and remote species, respectively, to peach in the subfamily Prunoideae of the Roasaceae, provides insight into the SC/SI evolution in Prunus. We discuss the significance of SC pollen part mutation in peach with special reference to possible differences in the SI mechanisms between Prunus and Solanaceae.

Alleles↗

Effect of yeast antagonist in combination with heat treatment on postharvest blue mold decay and Rhizopus decay of peaches.

The potential of using heat treatment alone or in combination with an antagonistic yeast for the control of blue mold decay and Rhizopus decay of peaches caused by Penicillium expansum and Rhizopus stolonifer respectively, and in reducing natural decay development of peach fruits, as well as its effects on postharvest quality of fruit was investigated. In vitro tests, spore germination of pathogens in PDB was greatly controlled by the heat treatment of 37 degrees C for 2 d. In vivo test to control blue mold decay of peaches, heat treatment and antagonist yeast, as stand-alone treatments, were capable of reducing the percentage of infected wounds from 92.5% to 52.5% and 62.5%, respectively, when peach fruits stored at 25 degrees C for 6 d. However, in fruit treated with combination of heat treatment and Cryptococcus laurentii, the percentage of infected wounds of blue mold decay was only 22.5%. The test of using heat treatment alone or in combination with C. laurentii to control Rhizopus decay of peaches gave a similar result. The application of heat treatment and C. laurentii resulted in low average natural decay incidences on peaches after storage at 4 degrees C for 30 days and 20 degrees C for 7 days ranging from 40% to 30%, compared with 20% in the control fruit. The combination of heat treatment and C. laurentii was the most effective treatment, and the percentage of decayed fruits was 20%. Heat treatment in combination with C. laurentii had no significant effect on firmness, TSS, ascorbic acid or titratable acidity compared to control fruit. Thus, the combination of heat treatment and C. laurentii could be an alternative to chemicals for the control of postharvest decay on peach fruits.

Antibiosis↗

Effect of storage temperature on the degradation of dimethoate in fortified orange and peach juices.

The effect of storage temperature on dimethoate degradation in fortified orange and peach juices was studied. The insecticide was aseptically injected into packed orange and peach juices and stored at 40, 15, and 0 degrees C. Samples were taken at regular time intervals and were examined for dimethoate residues. The residues were determined with a simple gas chromatographic method; the recoveries of dimethoate from orange and peach juices were found to be from 88 to 114% for both products. The limits of determination were 0.004 and 0.003 mg/kg, respectively. From the experimental data, rate constants, half-lives, and activation energies for the decomposition of dimethoate in orange and peach juices were evaluated. During the storage of fruit juices in refrigerated rooms (0 degrees C) half-lives of dimethoate were found to be largely extended, being 1733 days for orange juice and 2310 days for peach juice. Corresponding times for storage at 15 degrees C were 533 days for both juices and for storage at 40 degrees C 24 days for orange juice and 24.6 days for peach juice. The activation energy for dimethoate in orange juice was 22.3 kcal/mol and for peach juice, 21. 2 kcal/mol.

Beverages↗

A virtual peach fruit model simulating changes in fruit quality during the final stage of fruit growth.

A virtual fruit model simulating seasonal changes in several peach (Prunus persica (L.) Batsch) fruit quality traits during the final growth stage is presented. The quality traits considered are fruit size, the proportion of total fruit mass consisting of fruit flesh, dry matter content of the flesh and the concentrations of sucrose, glucose, fructose and sorbitol in the flesh, which are used to calculate a sweetness index. The virtual peach fruit model was developed by adapting and integrating three existing process-based models describing fruit dry mass growth, fruit fresh mass growth and sugar accumulation in the flesh into one complex system. Data sets of peach fruit growth and quality obtained from one field site over several years were used to estimate parameters and evaluate the virtual peach fruit model. Output from the model showed good agreement with the field data. Insight into the complex nature of the virtual peach fruit model, i.e., its ability to show emergent properties, was accomplished by conducting a series of theoretical experiments. The virtual peach fruit model was shown to be sensitive to management and environmental factors (leaf:fruit ratio, stem water potential and, to a lesser extent, weather). Its ability to generate simple laws relating to physiological variables and quality parameters was also demonstrated. Finally, the virtual peach fruit model was able to reveal complex behaviors resulting from changes in water potentials or leaf:fruit ratios over time.

Fruit↗

Hop stunt viroid strains from dapple fruit disease of plum and peach in Japan.

Viroids have been isolated from plum trees (Prunus salicina Lindley) affected with plum dapple fruit disease and from peach trees (Prunus persica Batsch) showing dapple fruit symptoms. The viroids were inoculated mechanically to cucurbitaceous plants, in which symptoms typical of hop stunt viroid (HSV) infection appeared. The complete nucleotide sequences of an isolate from plum and an isolate from peach (AF isolate) were shown to be identical, consisting of 297 nucleotides with a 93.6% sequence homology to HSV-hop. Another isolate from peach (A9 isolate) also consists of 297 nucleotides, but the sequence homology to HSV-hop is 99.7%, showing only one nucleotide replacement. These results indicate that these three viroids are strains of HSV, which we designate HSV-plum, HSV-peach (AF) and HSV-peach (A9), respectively. Comparative analysis of the nucleotide sequences of HSV strains from hop, grapevine, citrus, cucumber, plum and peach revealed variable and conserved regions in the HSV molecule. In Japan, these viroids are closely related not only to dapple fruit disease in plum cv. Taiyo, but also to dapple fruit symptoms on peach cv. Asama-Hakutou.

Base Sequence↗