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Inoculation Tests (inoculation + test)

Distribution by Scientific Domains

Life Sciences	66%
Chemistry	25%

Selected Abstracts

VIRULENCE LEVELS OF BIOFILM-GROWN LISTERIA MONOCYTOGENES LO28 ARE LOWER THAN THOSE OF PLANKTONIC CELLS IN AN ORAL INOCULATION TEST ON MICE

JOURNAL OF FOOD SAFETY, Issue 1 2007
ETIENNE ZUNDEL
ABSTRACT The aim of this study was to produce Listeria monocytogenes biofilms suitable for virulence assays and to determine whether the released bacteria had the same virulence potential as their planktonic counterparts. Biofilms of Listeria monocytogenes LO28 strain, with or without Sphingomonas paucimobilis CCL10 strain, containing up to 7 log10 cfu/cm2 were produced in polypropylene syringes. The virulence of strain LO28 was analyzed in mice after intravenous, subcutaneous and oral inoculation. Its virulence level in binary cultures was not significantly different from that of monocultures. L. monocytogenes LO28 virulence in biofilms was lower than that of their planktonic counterparts after oral inoculation. Our results suggest that biofilms pose no greater health risk to the consumer than planktonic bacteria. [source]

Pathogenicity of seed-associated fungi to Podocarpus falcatus in vitro

FOREST PATHOLOGY, Issue 1 2005
A. Gure
Summary Twenty-nine fungi that were isolated from seeds and female cones of Podocarpus falcatus from natural forests in Ethiopia, were assessed for their impact on seeds and seedlings of the same host. Based on the results from in vitro seed inoculation tests, we could group the fungi into five categories as: (i) isolates that were pathogenic only to seeds and had no obvious impacts on the germlings; (ii) isolates that were pathogenic only to the germlings; (iii) isolates that were pathogenic both to seeds and the emerging germlings; (iv) isolates that were more or less harmless; and (v) isolates that were germination promoters. Inoculation tests were also performed on 4,7-day-old aseptically grown seedlings. Fusarium oxysporum and Polyporus sp., were strongly pathogenic to both seeds and seedlings, while Nectria gliocladioides, Peniophora cinerea and Pestalotiopsis neglecta also demonstrated pathogenicity but to a lesser extent. Other isolates, e.g. Diaporthe spp. resulted in increased germination of P. falcatus seeds and no pathogenicity to seedlings. However, further investigations are required in order to find out how these fungi behave under nursery or field conditions. Résumé L'étude porte sur l'impact sur les graines et semis de Podocarpus falcatus de vingt-neuf champignons isolés de graines et fruits du même hôte en forêts naturelles en Ethiopie. D'après les résultats des inoculations de semences in vitro, les champignons peuvent être classés en 5 groupes: (i) les isolats pathogènes uniquement sur graines et sans effet apparent sur plantules; (ii) les isolats pathogènes uniquement sur plantules; (iii) les isolats pathogènes à la fois sur graines et sur plantules émergentes; (iv) les isolats non pathogènes; (v) les isolats favorisant la germination. Des inoculations ont également été pratiquées sur des semis de 4,7 jours produits en conditions axéniques. Fusarium oxysporum et Polyporus sp. montrent un fort pouvoir pathogène à la fois sure graines et semis, Nectria gliocladioides, Peniophora cinerea et Pestalotiopsis neglecta sont également pathogènes mais à un moindre degré. D'autres isolats, comme Diaporthe spp., induisent une augmentation de germination des graines de P. falcatus et ne sont pas pathogènes sur plantules. Des études complémentaires sont nécessaires pour déterminer le comportement de ces champignons en pépinières ou en conditions naturelles. Zusammenfassung Von Samen und weiblichen Zapfen von Podocarpus falcatus aus Naturwäldern in Äthiopien wurden 29 Pilze isoliert und auf ihre Pathogenität an Samen und Sämlinge der gleichen Art getestet. Anhand der Inokulationstests an Samen in vitro wurden die Pilze in 5 Klassen eingeteilt: (i) Pilze, die nur den Samen schädigen und keine Auswirkung auf den Keimling haben; (ii) Pilze, die nur den Keimling schädigen; (iii) Pilze, die sowohl den Samen als auch den Keimling schädigen; (iv) nicht pathogene Pilze; und (v) Pilze, welche die Keimung fördern. Zusätzlich wurden Inokulationstests an vier bis sieben Tage alten steril gekeimten Sämlingen durchgeführt. Fusarium oxysporum und Polyporus sp. waren sowohl an Samen als auch an Keimlingen stark pathogen, Nectria gliocladioides, Peniophora cinerea und Pestalotiopsis neglecta waren weniger stark pathogen. Andere Isolate, wie z.B. Diaporthe spp. waren apathogen und förderten die Keimung. Zur Abklärung des Verhaltens dieser Pilze unter Freilandbedingungen sind jedoch weitere Untersuchungen notwendig. [source]

Analyses of RAPD data for detection of host specialization in Sclerotinia homoeocarpa

PLANT PATHOLOGY, Issue 2 2000
T. Hsiang
Upgma analysis, principal component analysis, genetic diversity analysis and genetic distance analysis of RAPD data were used to assess the extent of host specialization in 50 isolates of S. homoeocarpa from five turfgrass hosts. In upgma analysis and principal component analysis, the occurrence of host specialization was not readily apparent based on visual inspection. Genetic diversity analysis showed significant differentiation among isolates from different host species (GST = 0.34, P < 0.001). The strongest evidence for some degree of host specialization came from the statistical analysis of genetic distances among isolates. By grouping pairwise genetic distances between isolates based on their host species, and analysing for average distance within the same host species and among different host species, it was found that the average distance within species was less than among species (P < 0.0001). An analysis of molecular variance of the genetic distances among isolates found that 32.3% of the total variation was attributable to host species. It is concluded that these isolates of S. homoeocarpa showed a weak level of host specialization, which was not readily apparent by upgma or principal component analyses, but was revealed by genetic diversity analysis and statistical analysis of genetic distances among isolates. Inoculation tests on different host species and tests using a greater number of isolates are required to confirm the extent of specialization. [source]

Surveys in Papua New Guinea to detect the presence of Trypanosoma evansi infection

AUSTRALIAN VETERINARY JOURNAL, Issue 12 2000
SA REID
Objective To confirm serological evidence that Trypano-soma evansi is present in Papua New Guinea. Design Three surveys were undertaken in PNG during 1997/1998. Animals were selected for sampling on the basis of convenience. Samples of blood were examined for the presence of T evansi b y the haematocrit centrifugation technique (HCT) and mouse inoculation test (MI). Sera were tested in the field using the card agglutination test for trypanosomiasis/T evansi(CATT). Bovine sera were tested at James Cook University using an antibody-detection ELISA (Ab-ELISA). Results from testing bovine sera with the Ab-ELISA and sera from wallabies with the CATT were analysed using FreeCalc to determine the probability that animals in these populations were infected with T evansi. Results A total of 545 serum samples were collected. during the three surveys of which 39 cattle, two pig and three agile wallaby samples were positive with the CATT. All bovine sera collected were negative when tested with an Ab-ELISA. T evansi was not isolated using the HCT or the MI from any of these animals. Conclusion Based on the Ab-ELISA results it was concluded that T evansi infection was not present in cattle in villages around Balimo at a minimum expected prevalence of 10% (P < 0.05) and, based on the CATT results, that infection was not present in wallabies on the Bula plain at a minimum expected prevalence of 10% (P < 0.1). These results indicate that it is unlikely that T evansi is endemic in PNG [source]

Pathogenicity of seed-associated fungi to Podocarpus falcatus in vitro

Lethality of Listeria monocytogenes in Fully Cooked and Vacuum Packaged Chicken Leg Quarters During Steam Pasteurization

JOURNAL OF FOOD SCIENCE, Issue 9 2003
R. Y. Murphy
ABSTRACT Fully cooked chicken leg quarters (160 g to 300 g) were injected to contain 107 to 108 colony-forming units (CFU)/g of a 5-strain Listeria monocytogenes culture. The inoculated leg quarters were vacuum-packaged in 0.08-mm-thick packaging films and then pasteurized at 96°C via steam. The heat transfer coefficient was about 760 W/m2 K in the steam cooker. Seven log10 (CFU/g) reduction of L. monocytogenes was achieved in about 22 min of steam treatment. Results from the inoculation tests agreed with the process lethality model prediction using the kinetic values that were obtained for the same product. This information helps industry to validate the lethality of L. monocytogenes in similar products during postcook pasteurization. [source]

Increased Susceptibility of Rice Following Insertion of Amylopullulanase Gene, to Brown Spot Caused by Bipolaris oryzae

JOURNAL OF PHYTOPATHOLOGY, Issue 9 2008
M.-Y. Ting
Abstract Transgenic rice expressing an amylopullulanase (APU) from the bacterium Thermoanaerobacter ethanolicus 39E produces grains which are less expensive to process for production of sugar syrup and protein-enriched flour. During risk assessment of the transgenic line in a field test, brown spot disease caused by Bipolaris oryzae was found more severe on the transgenic line APU than on its parental line TNG67. When lines APU and TNG67 were inoculated at seedling, tillering or heading stage with B. oryzae isolated from line TNG67, the disease was more severe on line APU than on line TNG67 at heading stage, but not at the seedling or tillering stage. However, when B. oryzae isolated from line APU was used in the inoculation tests, the disease was more severe on line APU than on line TNG67 at seedling stage, but not at the tillering or heading stage. To our knowledge, this is the first report of an unintended change in a transgenic plant to become more susceptible to a disease than the non-transgenic plant. [source]

A Suspension Culture Method for the Rapid Mass Culture of Cistella japonica Mycelium

JOURNAL OF PHYTOPATHOLOGY, Issue 9 2006
T. Yamanobe
Abstract Different methods were investigated for the rapid mass culture of Cistella japonica by using water extracts of some nutritional sources. In an agar culture test, there was little difference in mycelial growth in water extracts of wheat bran, rice bran and potato. In suspension culture with wheat bran extract, which is easily and cheaply available, the mycelium of C. japonica increased seven times more than that in agar culture after a month's incubation. C. japonica from suspension culture was pathogenic to Chamaecyparis obtusa. These results suggest that suspension culture in water extract of wheat bran can be adopted for the rapid mass culturing of C. japonica for use in inoculation tests. [source]

Potential of Trichoderma harzianum and T. atroviride to Control Botryosphaeria berengeriana f. sp. piricola, the Cause of Apple Ring Rot

JOURNAL OF PHYTOPATHOLOGY, Issue 4-5 2002
G. KEXIANG
Abstract Trichoderma harzianum T88 and T. atroviride T95 were tested for their efficacy in controlling apple ring rot (caused by Botryosphaeria berengeriana f. sp. piricola) in vitro and in the field. Isolates of T88 and T95 produced both volatile and non-volatile antibiotics that suppressed mycelial growth of the pathogen. Light and scanning electron microscopy showed that mycoparasitism by Trichoderma spp. of B. berengeriana f. sp. piricola resulted in penetration and disruption of hyphal cells, and thinning of cytoplasm of the pathogen. The culture filtrates of T88 and T95 in Czapek's liquid medium suppressed conidial germination of the pathogen, and the germination level was negatively correlated with the duration of culture of Trichoderma. In inoculation tests, 32 days after simultaneous inoculation or preinoculation with B. berengeriana f. sp. piricola and Trichoderma spp., the incidence of infected apple shoots was reduced, respectively, by 65.3,76.4% and 62.5,76.4%, and the index of infection reduced by 36.9,38.9 and 40.7,44.4, The effect of inoculating B. berengeriana f. sp. piricola 3 days after the antagonists were inoculated was greater (81.4,88.8%) than simultaneous inoculation (72.2,77.8%). Re-isolation from inoculated apple shoots demonstrated that the pathogen had been suppressed by Trichoderma. The ability to re-isolate the pathogen from apple after co-inoculation and pre-inoculation with Trichoderma spp. was reduced by 27.0,42.3% and 22.2,47.1%, respectively. The biocontrol field trial suggested that the B. berengeriana f. sp. piricola canker on apple shoots and stems and rotting fruit had been efficiently controlled by the application of spore suspensions of T. harzianum T88 and T. atroviride T95. The efficacy of control by Trichoderma is thus similar to that of routine chemical control. [source]

Characterisation of QoI-resistant field isolates of Botrytis cinerea from citrus and strawberry

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2009
Hideo Ishii
Abstract BACKGROUND: In 2004, field isolates of Botrytis cinerea Pers. ex Fr., resistant to strobilurin fungicides (QoIs), were first found in commercial citrus orchards in Wakayama Prefecture, Japan. Subsequently, QoI-resistant isolates of this fungus were also detected in plastic strawberry greenhouses in Saga, Ibaraki and Chiba prefectures, Japan. Biological and molecular characterisation of resistant isolates was conducted in this study. RESULTS: QoI-resistant isolates of B. cinerea grew well on PDA plates containing kresoxim-methyl or azoxystrobin at 1 mg L,1, supplemented with 1 mM of n -propyl gallate, an inhibitor of alternative oxidase, whereas the growth of sensitive isolates was strongly suppressed. Results from this in vitro test were in good agreement with those of fungus inoculation tests in vivo. In resistant isolates, the mutation at amino acid position 143 of the cytochrome b gene, known to be the cause of high QoI resistance in various fungal pathogens, was found, but only occasionally. The heteroplasmy of cytochrome b gene was confirmed, and the wild-type sequence often present in the majority of resistant isolates, indicating that the proportion of mutated cytochrome b gene was very low. CONCLUSION: The conventional RFLP and sequence analyses of PCR-amplified cytochrome b gene are insufficient for molecular identification of QoI resistance in B. cinerea. Copyright © 2009 Society of Chemical Industry [source]

Genotypic difference for the susceptibility of Japanese, Chinese and European pears to Venturia nashicola, the cause of scab on Asian pears

PLANT BREEDING, Issue 4 2008
K. Abe
Abstract Venturia nashicola, the cause of scab on Asian pears, is distinct from Venturia pirina, a causal fungus of European pear scab. Although scab caused by V. nashicola is one of the most serious diseases in the Japanese pear (Pyrus pyrifolia Nakai var. culta Nakai), information available regarding resistant breeding against V. nashicola is limited. In this study, 12 genotypes of Japanese pear, seven genotypes of Chinese pear (Pyrus ussuriensis Maxim.) and four genotypes of European pear (Pyrus communis L. var. sativa DC.) and/or their offspring were evaluated for susceptibility to V. nashicola with leaf and fruit inoculation tests. At 30,40 days after full bloom in their developmental stage, unfolded young leaves and fruit were inoculated with conidial suspensions of V. nashicola for each genotype, and the responses were rated at 30 days postinoculation for the inoculated leaves and at 42 days postinoculation for the inoculated fruits. No visible symptoms were found in European pear ,Bartlett' and ,La France' and their respective offspring ,290-36' and ,282-12', in the Japanese pear ,Kinchaku' and in the Chinese pears ,Cangxili' and ,Hongli'; these genotypes were evaluated as highly resistant to V. nashicola. Necrotic lesions without sporulation were observed in the Chinese pears ,Qiubaili', ,Manyuanxiang', ,Yuanbali' and ,Xiangyali', which were regarded as resistant. Sporulating lesions were formed on the other genotypes, such as the major Japanese pear cultivars ,Kosui' and ,Nijisseiki', which were regarded as susceptible. The response of inoculated leaves coincided well with that of inoculated fruit for each genotype. When the severity of scab symptoms on scab-susceptible genotypes was further rated with disease severity (DS) values, a genotypic difference was observed for overall DS values in a successive 2-year measurement among the susceptible genotypes. Based on the DS values of leaf and fruit scabs, the Japanese pears ,Niitaka', ,Shinko', ,Nijisseiki', ,Gold Nijisseiki', ,Osa Nijisseiki' and ,Shinsui' were considered to be less susceptible to V. nashicola than the typical susceptible cultivar ,Kosui'. [source]

Variation in the response of melon genotypes to Fusarium oxysporum f.sp. melonis race 1 determined by inoculation tests and molecular markers

PLANT PATHOLOGY, Issue 2 2003
Y. Burger
Screening of genotypes of melon (Cucumis melo) for resistance to wilt caused by Fusarium oxysporum f.sp. melonis is often characterized by wide variability in their responses to inoculation, even under carefully controlled conditions. The variability at the seedling stage of 17 genotypes susceptible to race 1 was examined in growth-chamber experiments. Disease incidence varied from 0 to 100% in a genotype-dependent manner. Using four combinations of light (60 and 90 µE m,2 s,1) and temperatures of (27 and 31°C), only light intensity showed a statistically significant effect. Marker-assisted selection for fusarium resistance breeding using cleaved amplified polymorphic sequence (CAPS) and sequence-characterized amplified region (SCAR) markers were compared using a single set of genotypes that included 24 melon accessions and breeding lines whose genotype regarding the Fom-2 gene was well characterized. The practical value of the markers for discriminating a range of genotypes and clarifying the scoring of phenotypes was also tested using a segregating breeding population which showed codominant SCAR markers to be useful in marker-assisted selection. [source]