bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Extracellular Polysaccharides (EPS) Produced in vitro by Pseudomonas phaseolicola I. Indications for a Polysaccharide Resembling Alginic Acid in Seven P. syringae Pathovars
Authors: Gross M. , Rudolph K. 
Published: May 2008

AbstractExtracellular polysaccharides (EPS) produced by Pseudomonas syringae pv. phaseolicola are obviously composed of two main components: the long known levan consisting of fructose, and a mannuronan consisting mainly of mannuronic acid (manA), thus resembling alginic acid (alginate). The identification of manA was established by TLC utilizing different developing systems, and by cellulose acetate electrophoresis in different buffers. References were authentic uronic acids and hydrolyzed authentic alginate. A rough quantification of the “alginate” present in crude EPS was achieved with a selective colour reaction which largely excluded compounds other than uronic acids.Levan was only synthesized with sucrose as primary carbon source. When grown on several other sugars and related compounds “alginate” was the predominant component of the EPS. Additionally, rhamnose, fucose, glucose and amino sugars were found in some instances in hydrolysates of crude EPS, suggesting the release of lipopolysaccharides (LPS) from the bacterial cell walls during culture. Growth on carbon sources not related to sugars resulted in these “LPS” as the main constituent of EPS. After cultivation with sucrose, the “alginate” was restricted to the “slime” fraction of the EPS. In the “capsular” fraction, levan was predominating.A screening program revealed the capacity to synthesize the “alginate” in six additional P. syringae pathovars: pisi, lachrymans, aptata, tomato, syringae, and glycinea.All of the strains tested so far produced levan from sucrose, however, the “alginate” was formed not by all of them. There was a tendency that fresh isolates produced more “alginate” than strains subcultured for an extended time in vitro. This was also true for the total amount of EPS.
Demonstration of the Specific Involvement of Coat Protein in Tobacco Mosaic Virus (TMV) Cross Protection using a TMV Coat Protein Mutant
Authors: Sherwood J. L. 
Published: May 2008

AbstractThe DT‐1G mutant of tobacco mosaic virus (TMV) which has no coat protein was used to study the specific involvement of coat protein in TMV cross protection in N. sylvestris. Leaves of N. sylvestris previously inoculated with the mutantor the common strain of TMV were challenged with either turnip mosaic virus (TuMV) or a strain of TMV (TMV‐N). Both TuMV and TMV‐N produce necrotic lesions on N. sylvestris. About one‐half as many lesions were produced by TuMV and TMV‐N on leaves, inoculated with the DT‐1G mutant compared with lesions produced by the same inoculum on control leaves. When leaves of N. sylvestris previously inoculated with the common strain of TMV were challenged with either TuMV or TMV‐N, TuMV produced about one‐half as many lesions as on control leaves whereas TMV‐N produced about one‐tenth as many lesions as on control leaves. A high level of non‐specific resistance was induced by the mutant without coat protein, but it did not specifically protect against TMV.
Virulence Frequencies Influenced by Host Resistance in the Host‐Pathogen System Wheat‐Powdery Mildew
Authors: Heun M. 
Published: May 2008

AbstractThe virulence spectrum for different regions in Germany in 1986 shows that only virulences for resistance genes Pm1, 4a, 7, 8 and Ml‐i are common in Northern Germany; in the Southern part only Pm3b and 9 (+Pm1+ 2) remain effective; the combination Pm2 + 6 is effective within the whole country. The selection pressure of resistance genes on virulences is complex, but was relatively stable under different environmental conditions in 1985 and 1986.
Electron Microscopy of an Isometric Caulimo‐Like Virus from Sweet Potato (Ipomoea batatas)
Authors: Atkey P. T. , Brunt A. A. 
Published: May 2008

AbstractA newly recognised virus with isometric particles 50 nm in diameter was detected in Ipomoea batatas (sweet potato) by graft‐transmission to I. setosa. Virus particles and intracellular inclusions, although not seen in infected I. batatus, were found in the cytoplasm of most cell types of I. setosa. The caulimo‐like particles were most abundant with vesicles immediately adjacent to inclusions. The ovoid or spherical inclusions, which differ markedly from those of caulimovi, ruses, have a large central lacuna and usually several smaller peripheral lacunae. Infected vascular parenchyma cells sometimes protrude into, and occasionally completely occlude, adjacent xylem vessels, observations possibly explaining the sudden wilting and premature senescence of infected leaves.
Some Properties of Moroccan Pepper Virus and Tombusvirus Neckar
Authors: Gallitelli D. , Russo M. 
Published: May 2008

AbstractSome unreported characteristics of moroccan pepper virus (MPV) and tombusvirus Neckar (TVN) are given in this paper. Virus particles have a sedimentation coefficient of 140 S (MPV) and 133 S (TVN) and a buoyant density of 1.357 (TVN) and 1.355 (MPV), g/cm3 in CsCl. They are constituted by a single protein species with a molecular weight of 43,000 (MPV) and 45,000 (TVN) which encapsidate a single species of nucleic acid with the apparent size of 4,700 nucleotides. The estimated percentage sequence homology of this genomic RNA with that of the type member of the group was 10% (MPV) and 15% (TVN). All these characteristics strongly suggest to consider both MPV and TVN as true tombusviruses.
Observations on a Mixed Soil‐Borne Wheat Mosaic Virus and Wheat Spindle Streak Mosaic Virus Infection in Durum Wheat (Triticum durum Desf.)
Authors: Rubies‐Autonell C. , Vallega V. 
Published: May 2008

AbstractBoth Wheat Spindle Streak Mosaic Virus (WSSMV) and Soil‐borne Wheat Mosaic Virus (SBWMV) were found on durum wheat plants (Triticum durum Desf.) grown in a field near Rome (Italy). The simultaneous occurrence of these pathogens was demonstrated by host‐symptomatology, pattern of disease occurrence in the field, mechanical transmission tests, as well as by the morphology of viral particles and of ultrastructural modifications. Negatively stained preparates of diseased leaves collected in early, spring showed WSSMV particles and cytoplasmic cylindrical inclusions. SBWMV particles were found only in samples collected later in the season. Ultrathin sections of infected leaves collected in early spring showed characteristic WSSMV modifications such as pinwheels and membranous bodies, whereas samples collected later in the season contained also SBWMV‐like crystalline aggregates. WSSMV infection appeared to develop and decline earlier than SBWMV in the leaves of durum wheat plants infected by both, viruses. WSSMV had not been reported in Italy before.
Application of Cluster Analysis for Establishment of Genetic Similarity in Gene‐For‐Gene Host‐Parasite Relationships
Authors: Lebeda A. , Jendrulek T. 
Published: May 2008

AbstractGenetic similarity and/or dissimilarity among virulence phenotypes of phytopathogenic organisms and generally in gene‐for‐gene relationships can be exactly expressed by cluster analysis. The present paper deals with the application of a definite hierarchical agglomerative clustering method based on μ‐connected clusters as a means for describing genetic structure of virulence in a set of 48 physiological races (isolates) of Bremia lactucae (lettuce downy mildew). A dendrogram and a minimums, panning tree were used to distinguish between virulence phenotypes of B. lactucae. Further application of the methods of numerical taxonomy to phytopathology is briefly discussed.
Transmission of Bacterium Corynebacterium michiganense pv. michiganense by Seeds
Authors: Tsiantos J. 
Published: May 2008

AbstractThe results of experiments on transmission of Corynebacterium michiganense pv. michiganense showed that the spread of the bacterium by artificially infested seeds varies, but it was confirmed that from artificially infested seeds few diseased plants can be grown. The results depend on the environmental conditions during experimentation and the method of assaying the seedlings. High relative humidity favours the spread of the pathogen. The use of selective media helped the detection ofthe pathogen in seemingly healthy plants. It was proved that host can have population of C. michiganense pv. michiganense in a resident phase. It is assumed that when conditions are favorable the pathogen multiplies and cause disease.
Occurrence of Mycoplasma‐like Organisms in Parenchyma Cells of Cuscuta odorata (Ruiz et Pav.)
Authors: Siller W. , Kuhbandner B. , Marwitz R. , Petzold H. , Seemüller E. 
Published: May 2008

AbstractIn shoots of the dodder Cuscuta odorata mycoplasma‐like organisms (MLO) were observed to occur in nearly all mature sieve elements. Their frequency within the sieve elements varied from a few organisms to high concentrations. In addition, MLO, were found in other cell types. By identifying these cells and investigating the location in the vascular tissue three different types of cells infected with MLO could be distinguished: (1) phloem parenchyma cells, (2) parenchyma cells separating the five vascular bundles of C. odorata and (3) cells in the outer region of the vascular system next to the cells looking like an endodermis. Within the cells of the types 2 and 3, MLO occurred in large numbers and at different morphological structures., Therefore, we assume that the MLO multiply in these cells.
Non‐Reciprocity of the Serological Relationship Between the Italian III Strain and Other Strains of Tobacco Mild Green Mosaic Virus
Authors: Wetter C. , Altschuh D. 
Published: May 2008

AbstractThe Italian III strain (It III) of tobacco mild green mosaic virus (TMGMV) could not be distinguished from other strains of TMGMV using three antisera to this strain in precipitin, immunodiffusion gel tests, and ELISA. Antisera to the strains U2, PTMV, G‐TAMV, and type TMGMV, however, were able to differentiate these strains from It III strain. The non‐reciprocity of the serological relationship may be explained by assuming that It III lacks a specific epitope that the other strains have or that the, corresponding region in It III is not immunogenic.
Arachidonic and Linoleic Acids Elicit Isoflavonoid Phytoalexin Accumulation in Phaseolus vulgaris (French bean)
Authors: Longland Annette C. , Slusarenko A. J. , Friend J. 
Published: May 2008

AbstractArachidonic and linoleic, but not α‐linolenic or γ‐linolenic acids, induced necrosis and the accumulation of isoflavonoid phytoalexins in leaves of French bean (Phaseolus vulgaris L.) cv. ‘Red Mexican'. The levels of phytoalexins which accumulated were similar to those found in an incompatible interaction between cv. ‘Red Mexican’and an avirulent race 1 isolate of Pseudomonas syringae pv. phaseolicola. Maximum amounts of phytoalexins accumulated in response to 1.6 mM fattyacids, as opposed to 3.3 or 0.6 mM. The most severe tissue necrosis was not accompanied by the highest levels of phytoalexin accumulation. In contrast to leaves, only trace amounts of phytoalexins were elicited in hypocotyls. The possible significance of, these results is discussed in terms of mechanisms leading to plant cell death and phytoalexin accumulation.
Activity of Glucanases of Zygorrhynchus moelleri in Relation to Antagonism Against some Soil‐Borne Plant Pathogenic Fungi
Authors: Brown Averil E. 
Published: May 2008

Abstract Zygorrhynchus moelleri antagonized some soil‐borne fungi on agar and in composts. Filtrates of Z. moelleri cultures contained high levels of β‐1,3‐glucanase (exoglucanase) and β‐1,3(4)‐glucanase (endoglucanase) when the fungus was grown on hyphal wall material from Rhizoctonia solani or Pythium intermedium as sole carbon source. Lower exo‐ and endoglucanase activities were produced on Fusarium oxysporum f. sp. lini (F.o.l.) hyphal walls while insignificant levels were produced on Z. moelleri hyphal walls. Protease was also produced when Z. moelleri was grown on hyphal wall material, but chitinase or cellulase were not detected. Optimum production of both glucanases occurred in media at pH,6 to 7 and activity was optimal at pH 5. The enzymes were active over a temperature range in excess of 20–50 °C but optimum activity occurred at 40 °C.Cell free culture filtrates containing exo‐ and endoglucanase activity lysed living hyphal walls of R. solani, P. intermedium, Verticillium albo‐atrum and F.o.l. although walls of the latter were least sensitive to lytic activity. The culture filtrates did not lyse living mycelium of Z. moelleri. Z. moelleri also produced substances inhibitory to growth of colonies of test fungi on agar.In glasshouse experiments disease severity in flax induced by R. solani and P. intermedium, in parsley by P. paroecandrum and in radish and Zinnia by P. intermedium was suppressed in composts inoculated with sporangiospore suspensions of Z. moelleri.
Detection by ELISA of Two Tobamoviruses in Orchids Using Monoclonal Antibodies
Authors: Dore I. , Dekker E. L. , Porta C. , Van Regenmortel M. H. V. 
Published: May 2008

AbstractFive monoclonal antibodies (McAbs) were raised to the tobamovirus, odontoglossum ringspot virus (ORSV). All five McAbs reacted with the virus in double antibody sandwich (DAS) ELISA but not in an ELISA using virus‐coated plates. All the McAbs recognized a panel of ORSV strains and isolates, although one of the antibodies reacted better with some isolates and another reacted less with certain isolates than with type ORSV. It was possible to use the same McAbs both as coating and as biotinylated antibody in DAS‐ELISA.None of the five McAbs was able to bind to orchid strains of tobacco mosaic virus (TMV). In order to detect strains of both viruses, ORSV and TMV, in infected orchids it was necessary to include also McAbs raised against TMV in the immunoassays. The use of a mixed polyclonal‐monoclonal antibody DAS‐ELISA system is advocated for detecting both tobamoviruses in orchids.
Corn Stunt Spiroplasma in the Leafhopper Euscelidius variegatus
Authors: Alivizatos A. S. 
Published: May 2008

AbstractCorn stunt spiroplasma (CSS) multiplied in all leafhoppers Euscelidius variegatus injected with a culture of CSS, reaching titres of over 1x106 colony forming units (cfu) per insect and 2x104 cfu per salivary gland of each insect. CSS could be isolated from the haemolymph and the salivary glands at any time after injection. The growth of CSS in culture was inhibited by insect extract at concentrations greater than the equivalent of 0.1 insect/ml.Transmission of CSS to sterile feeding solution and to broad beans were compared using 24 h feeding periods. A porportion of 1.7 % of injected leafhoppers began to transmit to sterile feeding solution through membranes by the 4th day after injection, and reached a maximum of 30 % by day 14. Similar insects started transmitting to broad bean plants on day 12 (2 %), reaching a maximum of 7.5 % by day 14. The number of spiroplasmas transmitted by each insect to sterile feeding solution increased from 3, cfu on day 4 to a maximum of 80 cfu by day 14.Helices were seen in the haemolymph at any time after injection. However, partially deformed cells were not present until the 1st week and clumps of 3–4 cells and small aggregates until the 3rd week after injection. The salivary glands of injected insects contained membrane‐bound “pockets” or “colonies” packed with pleomorphic, filamentous (helical and non‐helical) cells and aggregates. Intracellular colonies were always at the periphery of the acini and were easily detectable by fluorescence microscopy after staining with a DNA‐binding fluorescent stain. Pleomorphic and filamentous cells were also seen intercellularly in the salivary glands.
Isolation of Sordaria fimicola from Maize Stalks
Authors: Chambers K. R. , De Wet D. C. 
Published: May 2008

Abstract Sordaria fimicola, which does not appear to have been isolated from maize before, was isolated from stalks in the field throughout the growing season. The fungus occurred at low frequencies and was confined largely to the nodes. Although it was repeatedly isolated from maize stalks it appears to be an opportunistic inhabitant. In a greenhouse study it could not be re‐isolated from maize seedling roots although a reduction in dry weight accumulation, root length and plant height was recorded.
Presence of a Root Malformation Factor in Culture Filtrates of Fusarium moniliforme var. subglutinans1
Authors: Kumar J. , Singh U. S. , Beniwal S. P. S. 
Published: May 2008

AbstractThe presence of a root malformation factor, different from plant growth substances viz. NAA, GA3, Kinetin and reduced Glutathion was demonstrated in culture filtrates of Fusarium moniliforme var. subglutinans, a fungus commonly associated with malformed mango tissues. Culture filtrate extracts of the fungus caused curling and stunting of maize and pea roots and formation of flap like growth at the tip of wheat roots, but failed to induce malformation in bean plants as reported, for malformin.
Sclerotia of Botrytis as a Source of Primary Inoculum for Bunch Rot of Grapes in New South Wales, Australia
Authors: Nair N. G. , Nadtotchei A. 
Published: May 2008

AbstractSclerotia of Botrytis cinerea were found to be a source of primary inoculum for bunch rot of grapes in the Hunter Valley of New South Wales. Conidia‐bearing sclerotia were found on canes on grapevines. Resporulation of sclerotia was observed and sporogenic germination led to infection of flowers and berries. Sclerotia survived for eight months in untreated soil in the laboratory. Application of dicarboximides (procymidone, iprodione and vinclozolin) reduced infection of flowers and bunch rotcaused by the sporogenic germination of sclerotia.
Mode of Infection of Ascochyta Blight of Chickpea Caused by Ascochyta rabiei
Authors: Pandey B. K. , Singh U. S. , Chaube H. S. 
Published: May 2008

AbstractProcess of infection and histological changes with Ascochyta blight of chickpea caused by A. rabiei (Pass.) Labr. were studied by light microscopy. Germ tubes from conidia of the fungus penetrate the stem tissue at the juncture of two epidermal cells and form subepidermal aggregates until the fourth day. On the sixth day, yellowing and necrotisation of host tissue coincides with formation of mature pycnidia. Fungus causes extensive damage to cellulosic cell walls of parenchymatous cortical and pith tissues in advance of invading hyphae indicating involvement of cell wall degrading enzymes. Lignified tissues, particularly xylem tracheary elements, remain intact.
Ultrastructure of Inclusions Formed by Ribgrass Mosaic Virus in Leaf Cells
Authors: Ernwein Cornelia , Wetter Carl 
Published: May 2008

AbstractDiffrent types of cytoplasmic inclusions were observed in ultrathin sections of plants systemically infected with three different strains of ribgrass mosaic virus (RMV) (tobamovirus group). Tissue from uninoculated plants did not contain such inclusions. Most common were “rounded plates” consisting of layers of aligned virus particles 300 nm long. RMV also induced angled layer aggregates in Capsicum annuum plants. A novel type of inclusion for the tobamovirus group were the abundant spiral aggregates found in Digitalis purpurea, systemically infected with strain D of RMV. In these aggregates the virions become circularly arranged around a center. The orientation of the particles changes in such a way that virions being 300 nm apartare cut in the longitudinal and in the transverse direction respectively.
The Pattern of Bacterial Leaf Blight Disease Development and spread in Rice
Authors: Nayak P. , Reddy P. Ranga 
Published: May 2008

AbstractThe pattern of occurrence and spread of bacterial leaf blight among rice plants in the field was studied through the test of randomness of infected plants by fitting negative binomial distribution, ordinary runs and doublets analyses. The low k value obtained through negative binomial distribution indicated the clustering of infected plants. The high negative values of standardized Z in ordinary runs test at higher levels of incidence indicated non‐random pattern of occurrence and spread of the disease by alloinfection. Negative binomial distribution and ordinary runs test were preferred over doublets test to study the pattern of spread of bacterial leaf blight disease of rice because they revealed realistically the field situation.
Bell Pepper Mottle Virus, a Distinct Tobamovirus Infecting Pepper
Authors: Wetter Carl , Dore Isabelle , Bernard Monika 
Published: May 2008

AbstractBell pepper mottle virus (BPeMV) can be distinguished by symptomatology and host range from other tobamoviruses but a reliable identification needs serological tests. The relationships of BPeMV to tobacco mosaic virus (TMV), Odontoglossum ringspot virus (ORSV), tobacco mild green mosaic virus (TMGMV), and pepper mild mottle virus (PMMV) were investigated using precipitin drop tests on slides, immunodiffusion gel tests, double antibody sandwich enzyme‐linked immunosorbent assay (ELISA), and indirectELISA using enzyme‐linked goat anti‐rabbit globulins for the determination of antiserum titers and serological differentiation indices (SDI). Comparisons of SDIs and amino acid composition data demonstrated that BPeMV is a new species of the tobamovirusgroup. BPeMV, ORSV, PMMV, and TMGMV form a cluster within the genus (group) and could be considered as a subgenus of tobamoviruses.
Electron Microscopical and Serological Detection of Virus‐like Particles Associated with Lettuce Big Vein Disease
Authors: Vetten H. J. , Lesemann D.‐E. , Dalchow J. 
Published: May 2008

AbstractVery labile rod‐shaped particles measuring 324 and 152 nm × 18 nm were isolated only from lettuce plants affected with lettuce big vein (LBV) but not from healthy ones. An antiserum to these particles was prepared which enabled us to diagnose LBV‐affected plants, using immunosorbent electron microscopy (ISEM) and enzyme‐linked immunosorbent assay (ELISA). Clearly positive reactions were obtained in ISEM and ELISA even when symptoms of LBV‐affected plants raised in soil from various locations were indistinct. Higher ELISA values were obtained with extracts from leaves than with those from roots. In ISEM high numbers of particles were trapped from extracts of LBV‐affected plants with antiserum to tobacco stunt virus.
Alternative Gramineous Hosts of Leptosphaeria nodorum Including Two New Records for the U. S. A.
Authors: Khokhar L. K. , Pacumbaba R. P. 
Published: May 2008

Abstract Leptosphaeria nodorum was isolated from various wheat sources (seeds, seedling, straw, and volunteers) and from triticale, little wild barley, ryegrass, smooth bromegrass, aegilops, quackgrass, Bermuda grass, and air. The level of seed contamination in wheat cultivars varied from 3–63%. Initial detection of the pathogen from field samples of plant material varied from 5–58%. Four out of the 12 plates exposed to the air showed growth of the pathogen. The presence of spores from aerial sporetrapping decreases to zero by 30 December. The pathogen was undetected from the leaf samples of wheat and triticale from 15 January to 15 February. Spore size and cultural growth differed among the various isolates. Isolates from wheat straw, Bermuda grass, little wild barley, and triticale were fluorescent variable while the other isolates fluoresced under NUV light. Symptoms were induced when wheat cv.‘Callahan 513’ and four other grasses were inoculated with isolates of L. nodorum from various gramineous sources. The infection by the pathogen on ‘Callahan 513’ was greater than the infection of the same isolates in their gramineous weed hosts. Ryegrass and Bermuda grass were demonstrated as additional alternative gramineous hosts of L.nodorum in the United States.