| detection of xylella fastidiosa in potential insect vectors by immunomagnetic separation and nested polymerase chain reaction. | a sensitive and specific assay for detecting xylella fastidiosa in potential insect vectors was developed. this assay involves immunomagnetic separation of the bacteria from the insect, followed by a two-step, nested polymerase chain reaction (pcr) amplification using previously developed oligonucleotide primers specific to x. fastidiosa. a total of 347 leafhoppers representing 16 species were captured and sampled from american elm (ulmus americana l.) trees growing in a nursery where bacterial ... | 1997 | 9281861 |
| cerato-ulmin, a hydrophobin secreted by the causal agents of dutch elm disease, is a parasitic fitness factor. | dutch elm disease is caused by the aggressive ophiostoma novo-ulmi and the nonaggressive o. ulmi. both secrete the protein cerato-ulmin (cu). to determine what role cu plays in the pathology of dutch elm disease, we constructed a cu overexpression mutant of the nonaggressive o. ulmi h5. stable integration of a single copy of the cu gene from the aggressive o. novo-ulmi into the genome of the nonaggressive isolate resulted in increased secretion of cu protein. trials with american elm, ulmus amer ... | 1997 | 9344630 |
| auxin and ethylene regulation of diameter growth in trees. | recent studies on the phytohormonal regulation of seasonal cell-division activity in the cambium, primary-wall radial expansion of cambial derivatives, differentiation of xylem cells, and growth of the cortex in forest trees of the north temperate zone are reviewed. indol-3-ylacetic acid (iaa, auxin) has been characterized by combined gas chromatography-mass spectrometry (gc-ms) in the cambial region of abies balsamea, pinus densiflora, pinus sylvestris and quercus robur. all of the evidence sup ... | 1988 | 14972810 |
| broad-range and binary-range acyl-acyl-carrier protein thioesterases suggest an alternative mechanism for medium-chain production in seeds. | in the current model of medium-chain (c8-14) fatty acid biosynthesis in seeds, specialized fatb acyl-acyl-carrier-protein (acp) thioesterases are responsible for the production of medium chains. we have isolated and characterized fatb cdnas from the maturing seeds of elm (ulmus americana) and nutmeg (myristica fragrans), which accumulate predominantly caprate (10:0)- and myristate (14:0)-containing oils, respectively. in neither species were we able to find cdnas encoding enzymes specialized for ... | 1997 | 9193098 |
| evidence of sexual reproduction of woolly apple aphid, eriosoma lanigerum, in new zealand. | reproduction of the woolly apple aphid, eriosoma lanigerum (hausmann), can take place parthenogenetically or sexually when both host plants, apple (malus domestica borkh.) and elm (ulmus americana l.) are available. since elm is not commonly grown in new zealand, e. lanigerum, a major pest of apple, is thought to reproduce only parthenogenetically here. during our studies between 1999 and 2003, different morphs of e. lanigerum have been observed on apple trees, which were studied in more detail ... | 2005 | 17119609 |
| inhibition of phenylpropanoid biosynthesis in artemisia annua l.: a novel approach to reduce oxidative browning in plant tissue culture. | oxidative browning is a common and often severe problem in plant tissue culture systems caused by the accumulation and oxidation of phenolic compounds. the current study was conducted to investigate a novel preventative approach to address this problem by inhibiting the activity of the phenylalanine ammonia lyase enzyme (pal), thereby reducing the biosynthesis of phenolic compounds. this was accomplished by incorporating 2-aminoindane-2-phosphonic acid (aip), a competitive pal inhibitor, into cu ... | 2013 | 24116165 |
| komagataella populi sp. nov. and komagataella ulmi sp. nov., two new methanol assimilating yeasts from exudates of deciduous trees. | two new species of the methanol assimilating ascosporic yeast genus komagataella are described. komagataella populi sp. nov. (nrrl yb-455, cbs 12362, type strain, mycobank accession number = 564110) was isolated from an exudate on a cottonwood tree (populus deltoides), peoria, illinois, usa, and komagataella ulmi sp. nov. (nrrl yb-407, cbs 12361, type strain, mycobank accession number = 564111) was isolated from the exudate on an elm tree (ulmus americana), also growing in peoria, illinois. the ... | 2012 | 22302468 |
| functional categorization of unique expressed sequence tags obtained from the yeast-like growth phase of the elm pathogen ophiostoma novo-ulmi. | the highly aggressive pathogenic fungus ophiostoma novo-ulmi continues to be a serious threat to the american elm (ulmus americana) in north america. extensive studies have been conducted in north america to understand the mechanisms of virulence of this introduced pathogen and its evolving population structure, with a view to identifying potential strategies for the control of dutch elm disease. as part of a larger study to examine the genomes of economically important ophiostoma spp. and the g ... | 2011 | 21864383 |
| evaluation of insecticides for control of overwintering hylurgopinus rufipes (coleoptera: curculionidae). | a bark disk bioassay was used to assess the effectiveness of different insecticides for control of overwintering adult native elm bark beetles, hylurgopinus rufipes (eichoff) (coleoptera: curculionidae). insecticides were applied to the base of the trunks of living american elm trees, ulmus americana l., and bark disk samples were removed at intervals with a hole saw. adult h. rufipes were exposed in bioassay chambers for which the bark disks formed the floor of the chamber. in september 2005, c ... | 2011 | 21735908 |
| changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the black rock forest, hudson highlands, southeastern new york state. | we sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (agb) over 76 years (1930-2006) in the deciduous black rock forest in southeastern new york, usa. we used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate agb and carbon content. between the early 1930s and 2000, three species were extirpated from the forest (american elm (ulmus americana ... | 2008 | 18244941 |
| transgenic american elm shows reduced dutch elm disease symptoms and normal mycorrhizal colonization. | the american elm (ulmus americana l.) was once one of the most common urban trees in eastern north america until dutch-elm disease (ded), caused by the fungus ophiostoma novo-ulmi, eliminated most of the mature trees. to enhance ded resistance, agrobacterium was used to transform american elm with a transgene encoding the synthetic antimicrobial peptide esf39a, driven by a vascular promoter from american chestnut. four unique, single-copy transgenic lines were produced and regenerated into whole ... | 2007 | 17310333 |
| american elm (ulmus americana). | american elm (ulmus americana) is a valuable and sentimental tree species that was decimated by dutch elm disease in the mid-20th century. therefore, any methods for modifying american elm or enhancing disease resistance are significant. this protocol describes transformation and tissue culture techniques used on american elm. leaf pieces containing the midvein and petiole are used for explants. agrobacterium tumefaciens strain eha105 is used for transformation, with the binary vector pse39, con ... | 2006 | 17033055 |
| microbiology of wetwood: importance of pectin degradation and clostridium species in living trees. | wetwood samples from standing trees of eastern cottonwood (populus deltoides), black poplar (populus nigra), and american elm (ulmus americana) contained high numbers of aerobic and anaerobic pectin-degrading bacteria (10 to 10 cells per g of wood). high activity of polygalacturonate lyase (</=0.5 u/ml) was also detected in the fetid liquid that spurted from wetwood zones in the lower trunk when the trees were bored. a prevalent pectin-degrading obligately anaerobic bacterium isolated from these ... | 1981 | 16345848 |
| responses of floodplain forest species to spatially condensed gradients: a test of the flood-shade tolerance tradeoff hypothesis. | previous work in southeastern us floodplains led to the hypothesis that a tradeoff between flood and shade tolerance underlies species-specific responses to flooding and light, which drive forest regeneration. in systems where community turnover can occur with small-scale environmental changes, testing this hypothesis requires recognizing that turnover of species along the two gradients can be large relative to the spatial distances involved. we test the tradeoff hypothesis in an old-growth bott ... | 2006 | 16187107 |
| hypersensitivity to common tree pollens in new york city patients. | testing for tree pollen hypersensitivity typically requires the use of several tree pollens. identifying patterns of cross-sensitivity to tree pollens could reduce the number of trees used for testing. the goal of this study was to relate reported tree pollen levels to hypersensitivity patterns. three hundred seventy-one allergy patients were tested serologically for hypersensitivity toward prevalent tree pollens in the surrounding new york area over the years 1993-2000. specific tree pollens th ... | 2002 | 12221895 |