First Report of Penicillium carneum Causing Blue Mold on Stored Apples in Pennsylvania.

Blue mold decay occurs during long term storage of apples and is predominantly caused by Penicillium expansum Link. Apples harvested in 2010 were stored in a controlled atmosphere at a commercial Pennsylvania apple packing and storage facility, and were examined for occurrence of decay in May 2011. Several decayed apples from different cultivars, exhibiting blue mold symptoms with a sporulating fungus were collected.

Genetic diversity in Capsicum baccatum is significantly influenced by its ecogeographical distribution.

Background: The exotic pepper species Capsicum baccatum, also known as the aji or Peruvian hot pepper, is comprised of wild and domesticated botanical forms. The species is a valuable source of new genes useful for improving fruit quality and disease resistance in C. annuum sweet bell and hot chile pepper.

Organically versus conventionally grown produce: common production inputs, nutritional quality, and nitrogen delivery between the two systems.

One distinguishing conclusion found in most reviews of research studies comparing organically and conventionally grown produce is that variables shared alike by organic and conventional produce during production, harvest, and postharvest handling and storage were not applied. As a result, accurate and meaningful conclusions comparing the nutritional quality of organic and conventional produce are difficult to ascertain. Pairing common production variables such as the physical, biological, and chemical/nutritional attributes of soils, the irrigation sources and amounts, crop varieties, crop maturities and harvest dates, pre- and postharvest processing, handling, and/or storage methods, individually and collectively, provide greater clarity as to how inputs unique to organic and conventional systems affect produce quality.

Methyl jasmonate deficiency alters cellular metabolome, including the aminome of tomato (Solanum lycopersicum L.) fruit.

Exogenous treatment with jasmonates (JA) has been shown to reduce the levels of polyamines in many plants. But the role of endogenous JA on polyamine biosynthesis or other cellular metabolites has thus far remained uninvestigated. We developed transgenic tomato (Solanum lycopersicum L.

Relationship Between Host Acidification and Virulence of Penicillium spp. on Apple and Citrus Fruit.

ABSTRACT Penicillium expansum, P. digitatum, and P. italicum acidify the ambient environments of apple and citrus fruit during decay development.

Fresh-cut lettuce in modified atmosphere packages stored at improper temperatures supports enterohemorrhagic E. coli isolates to survive gastric acid challenge.

Incidences of foodborne outbreaks involving enterohemorrhagic Escherichia coli strains with mutations in a key regulatory gene, rpoS, have been reported. Incentives, if any, for losing this regulatory function are not clear since the RpoS regulator is required for the expression of several environmental stress tolerance genes. RpoS also positively regulates 2 of the 3 acid-resistance systems of E.

Biocontrol of Listeria monocytogenes on fresh-cut produce by treatment with lytic bacteriophages and a bacteriocin.

The fresh-cut produce industry has been the fastest-growing portion of the food retail market during the past 10 years, providing consumers with convenient and nutritious food. However, fresh-cut fruits and vegetables raise food safety concerns, because exposed tissue may be colonized more easily by pathogenic bacteria than intact produce. This is due to the higher availability of nutrients on cut surfaces and the greater potential for contamination because of the increased amount of handling.

Temperature-dependent autoxidation of conjugated trienols from apple peel yields 6-methyl-5-hepten-2-one, a volatile implicated in induction of scald.

Conjugated triene (CT) oxidation products of alpha-farnesene have long been thought to be involved in development of superficial scald in apple fruit. Early studies found that CT hydroperoxides and the volatile 6-methyl-5-hepten-2-one (MHO) are major in vitro autoxidation products of alpha-farnesene. However, it was recently shown that > or =99% of the oxidation products of alpha-farnesene that accumulate in apple peel are conjugated trienols (CTols), isomers of 2,6,10-trimethyldodeca-2,7,9,11-tetraene-6-ol.

Survival and Growth of Listeria monocytogenes on Fresh-Cut Apple Slices and Its Interaction with Glomerella cingulata and Penicillium expansum.

The food-borne human pathogen Listeria monocytogenes survived and its populations increased on cv. Delicious apple slices at 10 or 20°C in air or controlled atmosphere of 0.5% O and 15% CO, but did not grow at 5°C.

A new 1-aminocyclopropane-1-carboxylic acid-conjugating activity in tomato fruit.

A new conjugate, 1-(gamma-L-glutamylamino)cyclopropane-1-carboxylic acid (GACC), of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) is identified. The only previously identified conjugate of ACC is 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC). GACC, not MACC, was the major conjugate formed by crude protein extracts of tomato (Lycopersicon esculentum Mill cv Ailsa Craig) fruit pericarp and seeds incubated with [14C]ACC.

Purification and Characterization of 1-Aminocyclopropane-1-Carboxylic Acid N-Malonyltransferase from Tomato Fruit.

1-Aminocyclopropane-1-carboxylic acid (ACC) can be oxidized to ethylene or diverted to the conjugate 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC) by an ACC N-malonyltransferase. We developed a facile assay for the ACC N-malonyltransferase that resolved [14C]MACC from [14C]ACC by thin-layer chromatography and detected and quantified them using a radioisotope-imaging system. Using this assay, we showed that ACC N-malonyltransferase activity has developmental and tissue-specific patterns of expression in tomato (Lycopersicon esculentum) fruit.

Identification of Posttranslationally Modified 18-Kilodalton Protein from Rice as Eukaryotic Translation Initiation Factor 5A.

Using anther-derived rice (Oryza sativa L.) cell-suspension cultures, we have identified an 18-kD protein that is posttranslationally modified by spermidine and is influenced by endogenous polyamine levels. The posttranslationally modified residue has been identified as the unusual amino acid hypusine [N[epsilon]-(4-amino-2-hydroxybutyl)lysine] by reverse-phase high-performance liquid chromatography and gas chromatography-mass-spectrometry analyses.

Translational modification of an 18 kilodalton polypeptide by spermidine in rice cell suspension cultures.

When rice (Oryza sativa) cell suspension cultures are grown in the presence of [terminal methylenes-(3)H]spermidine, label is incorporated in a single polypeptide with a molecular mass of 18 kilodaltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Preincubation of cell cultures with polyamine biosynthesis inhibitors difluoromethylarginine and difluoromethylornithine, resulted in increased incorporation of the label into the 18 kilodalton polypeptide. In cells in which protein synthesis was arrested by cycloheximide, no label was detected in the 18 kilodalton polypeptide, suggesting a requirement for de novo protein synthesis.

Polyamine levels and tomato fruit development: possible interaction with ethylene.

Fruits of tomato, Lycopersicon esculentum Mill. cv Liberty, ripen slowly and have a prolonged keeping quality. Ethylene production and the levels of polyamines in pericarp of cv Liberty, Pik Red, and Rutgers were measured in relation to fruit development.

Transport and Compartmentation of 1-Aminocyclopropane-1-Carboxylic Acid and Its Structural Analog, alpha-Aminoisobutyric Acid, in Tomato Pericarp Slices.

The uptakes of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor to ethylene, and its structural analog, alpha-aminoisobutyric acid (alphaAIB) by tomato pericarp slices were investigated. Both uptakes show a biphasic (saturable-linear) dependence on external concentration of the transported amino acid. At low concentrations, ACC uptake is competitively inhibited by alphaAIB and vice versa.

Quantitative determination of indole-3-acetic Acid in sugarbeet leaves using a double standard isotope dilution gas chromatographic assay.

Quantitative levels of indole-3-acetic acid (IAA) were determined in leaf blades of two sugarbeet cultivars by a double standard isotope dilution assay using column chromatography followed by reverse phase C(18) high performance liquid chromatography and gas-liquid chromatography with nitrogen thermionic detection. The double standard method was validated as a quantitative tool by gas chromatography/selected ion monitoring mass spectrometry using 2,',4',5',6',7'-d(5)-IAA as the internal standard. Progenies of one breeding line that had been selected for a high taproot to leaf weight ratio were used to correlate IAA levels with varying leaf and plant size at day 31 from germination.

Effect of plant hormones on sucrose uptake by sugar beet root tissue discs.

Abscisic acid (ABA), auxins, cytokinins, gibberellic acid, alone or in combination were tested for their effects on short-term sucrose uptake in sugar beet (Beta vulgaris cv USH-20) roots. The effect of ABA on active sucrose uptake varied from no effect to the more generally observed 1.4-to 3.

Sucrose uptake and compartmentation in sugar beet taproot tissue.

Active sucrose uptake by discs of mature sugar beet (Beta vulgaris L. cv GW-D2 and USH-20) root tissue shows a biphasic dependence on external sucrose. At concentrations up to 20 millimolar sucrose, the active uptake mechanism appears to approach saturation, with an apparent K(m) of 3.

Reduction in Sink-Mobilizing Ability following Periods of High Carbon Flux.

Sink tissues may play a significant role in determining photosynthetic rates through their ability to mobilize assimilates. The objective in this study was to determine if the mobilizing ability of taproot sink tissues of sugarbeet (Beta vulgaris) could become limiting when assimilate supply was maintained at a high level for an extended period of time. Assimilate supply was either enhanced by CO(2) enrichment or reduced by shading.

Electrical potentials in stomatal complexes.

Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes and potential differences measured that occurred between cell compartments and the flowing bathing medium. The wall developed a Donnan potential that was between -60 and -70 millivolt in 30 millimolar KCl at pH 7. The density of the fixed charges ranged from 0.

Alkali Cation/Sucrose Co-transport in the Root Sink of Sugar Beet.

The mechanism of sucrose transport into the vacuole of root parenchyma cells of sugar beet was investigated using discs of intact tissue. Active sucrose uptake was evident only at the tonoplast. Sucrose caused a transient 8.

Binding of (45)Ca (2+) to particulate fractions of coleoptile tissue.

Using recently developed techniques, we have investigated the binding of (45)Ca(2+) to membrane preparations from corn (Zea mays L) and oat (Avena sativa L) coleoptile tissue. Scatchard plot analysis reveals at least two Ca(2+)-binding sites in each tissue, a high affinity binding site (K m=7.7×10(-7) M, n=6.

Selective effects of victorin on growth and the auxin response in Avena.

Victorin, the pathotoxin from the host-specific pathogen, Helminthosporium victoriae, promotes the growth of coleoptile segments when given at concentrations that are high but which still show selective effects on susceptible and resistant tissue. The latent period in the growth response of both susceptible and resistant tissue is about 3.6 minutes compared to 11.