Damp Chamber Research Articles

First Report of Cylindrocladium buxicola on Buxus sempervirens in Spain.

Cylindrocladium buxicola Henricot, included in the EPPO alert list until November 2008, causes a dangerous foliar disease on Buxus spp. that has been recorded in several European countries and New Zealand (3,4). Buxus sempervirens L. (common boxwood) is one of the oldest ornamental garden plants in Europe. In September 2008, we received 10 2- to 3-year-old potted plants of B. sempervirens cv. Suffruticosa from a nursery in Galicia (northwest Spain) where ≈60% of the plants were affected and had finally defoliated. Diseased plants showed dark brown-to-black spots on the leaves and black streaks on the stems (3,4). To induce sporulation, diseased leaves and stem pieces were incubated in damp chambers at 22°C. A Cylindrocladium sp. was obtained. Four single conidial isolates were plated onto carnation leaf agar under near-UV light at 25°C for 7 days (2,3). Only conidiophores of the isolates growing on the surface of the carnation leaves were examined microscopically (1,3). Macroconidiophores were comprised of a stipe, a stipe extension, a terminal vesicle, and a penicillate arrangement of fertile branches (2). The stipe extension was septate, hyaline, and 90 to 165 × 2 to 4.5 μm (from the highest primary branch to the vesicle tip) (1) terminating in an ellipsoidal vesicle (6 to 11 μm in diameter) with a papillate apex. The widest part of the vesicle was above the middle. Primary branches were mainly aseptate or one septate (12 to 35 × 3 to 6 μm), secondary branches were aseptate (11 to 21 × 3 to 6 μm), and tertiary branches were rare. Each terminal branch produced two to five phialides (9 to 20 × 2.5 to 5 μm) that were reniform and aseptate. Conidia were cylindrical, straight, and one septate (56 to 75 × 4 to 6 μm). Chlamydospores were dark brown and aggregated to form microsclerotia. Cardinal temperatures of Cylindrocladium isolates on 2% malt extract agar ranged from 7 to 28°C (optimum 25°C). The 5' end of the β-tubulin gene was amplified using primers T1 and Bt2b (3), and PCR products were sequenced directly and deposited in GenBank (Accession No. FJ696535). Comparison of the sequence with others available in GenBank showed 100% homology with those previously identified as C. buxicola (Accession Nos. AY078123 and AY078118). Pathogenicity of one representative isolate was confirmed by inoculating stems and leaves of four 3- to 4-year-old plants of B. sempervirens cv. Suffruticosa. Leaves were inoculated by spraying a spore suspension of the fungus (1 × 106 conidia per ml). For the stems, agar pieces of 1-week-old cultures grown on malt extract agar were placed and sealed with Parafilm. As a control, four plants were inoculated with agar malt plugs and sterile distilled water. Plants were incubated at 22°C and 95% humidity. Symptoms identical to ones previously described appeared 4 days after inoculation. C. buxicola was reisolated from inoculated plants but not from the controls. On the basis of morphological and physiological characteristics, pathogenicity, and the DNA sequencing of the β-tubulin gene, the isolates obtained from B. sempervirens were identified as C. buxicola (3). To our knowledge, this is the first report of C. buxicola on B. sempervirens in Spain.

Records of Coprophilous Fungi from the Lesser Antilles and Puerto Rico

Records of 54 species of coprophilous fungi obtained by incubating, in damp chambers, 21 samples of dung from mammalian herbivores from Puerto Rico, St John (USVI), Guadeloupe (France), Dominica and St Lucia are presented. Many are apparently new records for the region, and the distribution and occurrence of unusual or interesting species is discussed.

Variation of Soil Mycoflora in Decomposition of Rice Stubble from Rice-wheat Cropping System

The colonization pattern and extent of decay produced in paddy stubble by soil inhabiting mycoflora were done by using nylon net bag technique. Among the three methods used for isolation of fungi, dilution plate technique recorded the highest number of fungi followed by damp chamber and direct observation method. Nutrient availability and climatic conditions (temperature, humidity and rainfall) influenced the occurrence and colonization pattern of fungi. Maximum fungal population was recorded in October (48.99 × 104/g dry litter) and minimum in May (11.41 × 104/g dry litter). Distribution of Deuteromyeetous fungi was more in comparison to Zygomycetes, oomyeetes and aseomyeetes. In the early stage of decomposition Mucor racemosus, Rhizopus nigricans, Chaetomium globosum and Gliocladium species were found primarly whereas at later stages of decomposition preponderance of Aspergillus candidus, Torula graminis, Cladosporiun dadosporioides and Aspergillus luchuensis was recorded.

Microfungal assemblage on Quercus ilex leaf litter in Tuscany, central Italy

We investigated the microfungal assemblage on Quercus ilex leaf litter within the Viburno-Quercetum ilicis ornetosum, from five coastal stands, three litter layers, and two seasons (spring and autumn). The microfungal assemblage was determined by direct observation, collection, and identification of filamentous microfungi colonizing the leaf litter after incubation in damp chambers. The assemblage was characterized by the presence of two dominant species, Beltrania rhombica and Beltrania querna, which seemed to be strongly related to the plant material, and a group of fungal species, with considerable relative frequency values, strongly affected by the season. The results showed a similar pattern of microfungal species composition among the stands and the litter layers.

Use of spectrophotometry as a tool to quantify the sporulation of Penicillium allii in garlic lesions

A technique to measure the concentration of Penicillium allii conidia in damp chamber experiments by spectrophotometry was developed. A negative linear correlation (R²=0.56) was observed between transmittance at 340 nm and the concentration of P. allii conidia in water agar 0.05%. The equation that relates transmittance (T) with concentration (conidia mL-1) (y) is: y = 9.3 10(6) - 86497 T. The method was assayed by inoculating 43 P. allii strains in two garlic cultivars. The method proved to be more rapid than the traditional use of a hemocytometer with an improved accuracy. The CV of the number of conidia per hemocytometer reticule was of 35.04%, while the transmittance CV was of 2.73%. The extreme values chosen for T were 40 and 80 because the sensitivity of the method decreased when concentrations of conidia were out of this range.

On‐site real‐time PCR detection of Phytophthora ramorum causing dieback of Parrotia persica in the UK

In Europe Phytophthora ramorum mainly causes dieback of Rhododendron and Viburnum, but in the UK it has also been reported on other ornamentals including Hamamelis (Giltrap et al., 2004) as well as on a limited number of tree species (Brasier et al., 2004). In November 2004, Defra's PHSI collected samples from a public garden in south Wales where P. ramorum was under eradication. Each sample was tested on-site by CSL using real-time (TaqMan®) PCR for P. ramorum on a Cepheid SmartCycler (Tomlinson et al., 2005). This identified P. ramorum on Parrotia persica (Persian ironwood; Hamamelidaceae), which was causing necrotic leaf lesions and twig dieback. Duplicate material was also sent to CSL where P. ramorum was consistently isolated from both stem and leaf tissue following surface decontamination and isolation onto semi-selective medium (Lane et al., 2002). An ITS sequence was obtained from a culture of P. ramorum isolated from P. persica (GenBank DQ066919) and this was identical to other P. ramorum isolates on GenBank. Pathogenicity of the isolate was confirmed by wound-inoculating healthy leaves of P. persica with mycelial plugs and incubating these in a damp chamber at room temperature (c. 20°C) in the laboratory for six days. Extensive lesions developed on the leaves and the pathogen was re-isolated from the leading edge; thus completing Koch's postulates. Healthy wounded leaves, inoculated with agar alone, did not develop symptoms. This is the first report of P. ramorum affecting P. persica. The infected plant was destroyed and measures were taken to eradicate the pathogen according to European Union phytosanitary legislation and the EU was notified. We would like to thank Mr T. Davies for his help in confirming the identity of the host and for technical assistance with sampling. Funding for this work was provided by Defra's Plant Health Division and quarantine material was processed and held under Defra licence PHL 251A5016 (02/2005).

First report of Penicillium allii as a field pathogen of garlic (Allium sativum)

Blue mould disease in garlic (Allium sativum) is associated worldwide with various Penicillium species, and has been attributed to significant annual crop losses in Argentina; the world's second largest exporter of garlic. To identify the pathogenic Penicillium species responsible, affected plants were sampled in La Consulta station (33°45′ S, 69°02′ W) and placed in a damp chamber. Characteristic disease symptoms are stunted and chlorotic plants with withered leaves and reduced bulb size. Bulbs are often covered with blue/green conidial masses. Isolations were made from fungal colonies emerging on affected bulbs. Pure cultures (IBT 26466, 26467, 26511 and 26512; CMB collection, BioCentrum-DTU, Denmark) were initially identified by micromorphology as Penicillium allii, and identifications were confirmed by comparing reversed phase-HPLC secondary metabolite profiles with those of P. allii type strains. To confirm pathogenicity, sterilized garlic cloves were injured with a needle and inoculated with 5 µL P. allii spore suspensions (adjusted to 5 × 106 conidia mL−1). Inoculated cloves were planted in a field not previously cultivated with garlic, and the original disease symptoms were produced on inoculated plants while water-inoculated control plants remained healthy. The survival rate of inoculated plants was 68% and P. allii was reisolated from diseased field plants. Penicillium viridicatum was first reported as the causal agent of blue mould of garlic in Argentina (Gatica & Oriolani, 1984) before the characterization of P. allii (Vincent & Pitt, 1989). Penicillium allii is micromorphologically similar to P. viridicatum and both species produce yellow exudates in pure culture. To compare pathogenic ability, standard P. viridicatum strains IBT 16939 and 15053 were inoculated into sterilized garlic cloves and incubated for 12 days. The P. viridicatum strains were not able to sporulate on the garlic cloves. Penicillium hirsutum was recently reported as a pathogen on garlic in Argentina (Cavagnaro et al., 2005). However, P. allii but not P. hirsutum has been reported as an aggressive pathogen of garlic in comparative pathogenicity trials conducted in damp chambers (Overy et al., 2005). The results reported here suggest that P. allii, rather than P. hirsutum or P. viridicatum, is the pathogenic species responsible for garlic crop losses due to blue mould rot in Argentina. This is the first report confirming P. allii as a field pathogen of A. sativum. This work was partly supported by project Pict # 0803687 of Argentina.

NUMERICAL SIMULATION ON THE DYNAMIC CHARACTERISTICS OF A TWO-STAGE WATER HYDRAULIC RELIEF VALVE

The mathematical model for a novel two-stage water hydraulic relief valve is estabilished. Numerical simulation on its dynamic characteristics is analysed. Simulation results clarify that setting damping chamber at the pilot stage is benefit to improve the pilot valve's stability. The main valve's differential working pressure can be decreased greatly by adding a suitable throttle for the purpose of reducing cavitation, enhancing the valve's performance and service life. The results also show that the upper chamber volume V12 of the main valve, the inlet chamber volume V2 of the pilot valve and the inlet chamber volume V0 of the relief valve influence the relief valve's dynamic characteristics markedly.

Identification, Evolution, and Regulation of Expression of Guinea Pig Trappin with an Unusually Long Transglutaminase Substrate Domain

Trappins are found in human, bovine, hippopotamus, and members of the pig family, but not in rat and mouse. To clarify the evolution of the trappin genes and the functional significance of their products, we isolated the trappin gene in guinea pig, a species belonging to a rodent family distinct from rat and mouse. Guinea pig trappin was confirmed to encode the same domain structure as trappin, consisting of a signal sequence, an extra large transglutaminase substrate domain, and a whey acidic protein motif. Northern blot analysis and in situ hybridization histochemistry as well as immunohistochemistry demonstrated that guinea pig trappin is expressed solely in the secretory epithelium of the seminal vesicle and that its expression is androgen-dependent. We confirmed that guinea pig trappin is cross-linked by prostate transglutaminase and that the whey acidic protein motif derived from guinea pig trappin has an inhibitory activity against leukocyte elastase. Genome sequence analysis showed that guinea pig trappin belongs to the family of REST (rapidly evolving seminal vesicle transcribed) genes.

Orthogonal trap time‐of‐flight mass spectrometer using a collisional damping chamber

We report a new hybrid mass spectrometer, which is a combination of a quadrupole ion trap and an orthogonal time-of-flight (TOF) mass spectrometer. This new configuration consists of a collisional-damping chamber (CDC) inserted between an MSn-capable ion trap and a high-mass-accuracy orthogonal-TOF mass spectrometer. Because the CDC converted an ion packet into an energy-focused and quasi-continuous beam, a high mass resolution of over 10,000 and a high mass accuracy of better than 3 ppm were achieved. Moreover, the ratio of the maximum detectable m/z to the minimum detectable m/z, which is referred to here as the mass window, was improved to more than 10.

First report of ramorum bud and leaf blight (Phytophthora ramorum) on Syringa vulgaris in the UK

The recently described pathogen Phytophthora ramorum (Werres et al., 2001) causes tree mortality (Rizzo et al., 2002), dieback and leaf blight on various ornamentals and understory plants (Inman et al., 2003; Lane et al., 2003). Due to the potential threat to European flora from P. ramorum, EC emergency legislation was introduced in November 2002. During March 2003, a Syringa vulgaris plant originating from a nursery in Scotland was examined by SASA. The leaves had yet to develop, but the terminal bud and some axillary buds were blackened and dead. A Phytophthora sp. morphologically typical for P. ramorum was isolated (Werres et al., 2001). The culture was slow-growing with weakly coralloid mycelium. Sporangia were sympodial, semipapillate, deciduous with a short (< 5 µm) pedicel (40–80 µm × 20–32 µm). Chlamydospores (25–72 µm) were also present. The culture tested positive for P. ramorum by TaqMan® PCR (K. J. D. Hughes, unpublished data). Subsequently, two separate samples of S. vulgaris were received at CSL during June 2003, both nursery-grown container plants from separate sites in England. Each plant had extensive greyish-brown, diffuse, water-soaked leaf lesions. Isolations once again conformed to P. ramorum and were confirmed by TaqMan® PCR. Pathogenicity was confirmed by inoculating healthy, unwounded detached leaves of S. vulgaris with a 9 mm plug from the edge of the original lilac isolate. After 1 week's incubation (18°C in a damp chamber), typical lesions were seen. Phytophthora ramorum was re-isolated, thereby completing Koch's postulates. No symptoms were observed on control leaves. Subsequent tests on whole lilac plants produced identical leaf lesions. Interestingly, profuse sporangia were produced from affected areas and the leaves abscised within a few days of infection. Following confirmatory diagnosis, statutory plant health action was taken to eradicate the disease. This is the first ever report of P. ramorum affecting S. vulgaris.

Puccinia horiana

<i>Puccinia horiana</i>

THIS ARTICLE HAS BEEN WITHDRAWN: Glomerella acutata

THIS ARTICLE HAS BEEN WITHDRAWN: <i>Glomerella acutata</i>

Diversity of endophytic fungi in the roots of mangrove species on the west coast of India.

Because mangrove plant species are a valuable source of useful metabolites, their endophytes have gained more importance. Randomly sampled surface-sterilized whole root segments of four mangrove plant species, Acanthus ilicifolius, Avicennia officinalis, Rhizophora mucronata, and Sonneratia caseolaris from the mangroves of Udyavara (Karnataka) on the west coast of India, were characterized for fungal communities by direct plating, damp chamber, and bubbling chamber incubation methods. The richness of endophytic fungal species from whole root segments after direct plating and damp chamber incubation was greatest for R. mucronata than for other plants (18 vs. 8-13). Incubation of whole root segments in bubbling chambers yielded conidia of two freshwater hyphomycetes: Mycocentrospora acerina (in Avicennia officinalis) and Triscelophorus acuminatus (in R. mucronata and in S. caseolaris). Surface-sterilized whole root and root bark segments of R. mucronata sampled from the mid-tide level on direct plating yielded more fungi than that of the root segments sampled from low-tide and high-tide levels. The greatest number of isolates, species richness, and diversity of fungi were shown by the whole root segments of R. mucronata from the mid-tide level. Rarefaction indices also revealed the highest expected number of species out of 150 random isolations from the mid-tide level samples of whole root and root bark segments of R. mucronata. The present study showed that fungi in mangrove roots are composed of a consortium of soil, marine, and freshwater fungi.

COMPETENCE OF PEAR SHOOT AND FRUIT WOUNDS FOR ERWINIA AMYLOVORA INFECTION

Pruning and artificial ‘hailstone wounds’ on pear shoots and needle wounds in fruitlets were contaminated every 6 hours, starting from a few seconds after injury, and up to 66 h with known inoculum doses of a virulent strain of Erwinia amylovora. A single wound was made on each shoot and fruitlet. Cankers on shoots and brown areas on fruits caused by successful infection were observed, respectively, 20 and 8 days after contamination at 25±2°C. The shoot wounds were progressively less competent for infection as the interval increased between wounding and contamination. The largest reduction in competence occurred in the first 24 h after wounding (from 80-85% successful infections to approximately 10-20%). The pear shoot pruning wounds were still competent after 48 h and up to 60 h, although less than 5% of inoculations were successful. Acropetal cankers developed above the ‘hailstone wounds’ between 35 and 66 h after wounding. Wounds on fruits kept in a damp chamber remained competent longer than those on young pear tree shoots kept at 50-90% relative humidity. The variation in competence in the pear shoot and fruitlet wounds is discussed and compared with other bacterial host-pathogen systems.

Coprophilous Discomycetes from the Azores

Summary. Coprophilous discomycetes from the Azores obtained in the field or from dung samples later incubated in the laboratory are reported based on two visits to the Islands in 1995 and 1996. Other species previously known from the Islands are also noted, making a total of 31 species, of which all except Coprotus, Lasiobolus and Thelebolus belong in the order Pezizales. and later incubated in damp chambers to study the succession of fungi present. In addition, coprophilous fungi were collected directly in the field when encountered on older dung samples, particularly those of cow. The present paper discusses the discomycetes obtained, all of which except Coprotus, Lasiobolus and Thelebolus belong to the order Pezizales. Other coprophilous species previously known from the Islands are also noted, making a total of 31 species. The Azores archipelago, located on the Mid-Atlantic Ridge some 1250 km west of the nearest part of Europe, is of tertiary age and comprises nine main islands. These are volcanic in origin and have never been connected to any land mass. Colonisation by European settlers took place during the 15th century, since when the inevitable influence of human activity has had a significant and often severe influence on the native flora and fauna, including the mycological composition of the Islands (Dennis et al. 1977). The Islands have no native herbivorous mammals, although the rabbit (Oryctolagus cuniculus) has long been established (see Godman 1870) and is evidently now widely naturalised and fairly common. Dung samples obtained during these visits were, therefore, mainly from domesticated species, viz. donkey, horse, cow, goat and sheep, with several samples of rabbit dung and two of uncertain identification, perhaps either goat or sheep (samples no. 4 & 14 below).

Torsional vibration damper, particularly for the clutch disk of a motor vehicle friction disk clutch

The torsional vibration damper which is suited in particular for the clutch disk of a motor vehicle friction clutch has two damper parts (13, 17) rotatable relative to one another around a common rotational axis (7) over a defined rotational angle, which damper parts (13, 17) together enclose at least one, preferably, at least three, damper chambers (33, 35) sealed outwardly and at least partially filled with a hydraulic fluid. A roller body (37) is arranged in each damper chamber (33, 35) which roller body (37) divides the damper chamber (33, 35) in the circumferential direction into two spaces (39, 41) whose relation of volume changes during the relative rotation of the damper parts (13, 17). A throttle connection (47) between the two spaces (39, 41) makes possible the compensation of the hydraulic fluid as a by-pass connection to the roller body (37). The damper chamber is formed by means of two recesses (33, 35) located opposite one another and with volumes varying from one another in faces (29, 31 ) of the damper parts (13, 17), which faces complement one another, adjoin one another on opposite sides and move relative to one another during relative rotation. The circumference of the roller body (37) is in a friction-locking or form-locking drive rotational contact with mutually oppositely located faces (43, 45) of the two recesses (33, 35) and rolls without slipping in the recesses. The roller body is formed particularly resilient and is fixed in the recesses (33, 35) under its own spring pretensioning. The roller faces (43, 45) of the recesses (33, 35) are so formed that an increasing pretensioning force and thus a restoring moment acting contrary to the torsional torque results as the torsional angle increases. Such a torsional vibration damper acts hydraulically as well as a spring damper and permits relatively large torsional angles.

Brown and Red Stain in Ponderosa Pine Lumber

In past years there has been much research on blue stain in pine sapwood especially in pines killed by bark beetles (1). One year ago, a brown stain was observed in one inch ponderosa pine (Pinus ponderosa Laws) boards brought to the Colorado State University wood research laboratory for kiln drying. Samples were obtained of this stained wood and the brown stain fungus was readily isolated (Figs. 1, 2).1 In culture, the fungus grew fairly rapidly with brown mycelium but developed no conidia or fruiting structures by which it could be identified. Recently, the Wood Research Laboratory obtained one thousand 2 x 4's cut from ponderosa pines from northern New Mexico. The trees were from fairly dense young stands so that they contained much sapwood. They were held in moist condition in the Wood Research Laboratory with plastic sheets so that the sapwood became infested with blue stains and molds such as fast-growing Trich? oderma and Penicillium species. Examination also disclosed scattered pockets of a brown stain in many ofthe 2 x 4's. Isolations from this brown stain proved it to be caused by the same fungus as that from ponderosa pine boards obtained earlier. Parts ofthe 2 x 4's containing brown stain were placed in a damp chamber. In 3-4 wk, brown, perithecium-like structures developed on the surface of the brown-stained areas. White, waxy columns issued from the tips of these fruiting bodies and consisted of hyaline cylindrical spores or spermatia about 8 x 1 ^m. They did not germinate to form cultures when transferred in mass to culture medium. The fruiting bodies were about 103 mm in diam, and dark brown to black. It is hoped that future investigators will discover this fungus in mature condition on overwintered pine wood for positive identification.

Impact tool with damping chambers

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Impact absorbing strut

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