bluuebunny/crossref_metadata_2025_split huggingface dataset:
Whiteflies Population and its Impact on the Incidence of Tomato Yellow Mosaic Virus in Venezuela
Authors: Anzola D. , Lastra R. 
Published: May 2008

AbstractThe heavy incidence of Tomato Yellow Mosaic Virus in Venezuela is related to the high population densities of its vector, the whitefly Bemisia tabaci Genn. The main factor affecting the population of the vector is the rainfall pattern; during the rainy season the populations are low but they increase rapidly in the drier months. A good correlation was found between the number of whiteflies trapped and the incidence of infested plants. It seems that in the low laying areas of the tropics the temperature does not have a marked effect on the whitefly population since it remains quite stable throughout the year.
Root Rot of Trifolium subterraneum Induced by Fusarium solani
Authors: Mills L. J. 
Published: May 2008

AbstractA fungus disease of Trifolium subterraneum, previously unknown in South Africa, was identified as Fusarium root rot caused by F. solani (Mart.) Sacc. Diseased plants were severely stunted. The characteristic internal root discolouration observed in the field, is described. The disease occurred mainly between Swellendam and Humansdorp in the southern and south‐eastern Cape Province. The subterranean clover fields inspected were between 95 and 100 % infected with the root rot disease. T. repens and T. pratense were also susceptible.
Comparison of Some Isolates of Potato Leaf Roll Virus in Poland
Authors: Syller J. 
Published: May 2008

Abstract18 PLRV isolates differed in severity of symptoms induced on Physalis floridana and on three potato cultivars (Osa, Pola, and Giewont). Reactions of potato cultivars to individual isolates were not always related.Some isolates induced more severe symptoms than others in all host plants. Isolates producing more severe symptoms reached a higher concentration in potato cultivars (evaluated with ELISA test) and were more virulent to Capsella bursa‐pastoris.An interaction between PLRV isolates and host plants could be demonstrated. In general, the severity of the reaction of cv. Pola was related to that of P. floridana but not to the reaction of cvs. Osa and Giewont. The reactions of cvs. Osa and Giewont were closely related.All six isolates selected for a more detailed study could infect C. bursa‐pastoris with obvious disease symptoms if potato cv. Osa served as source of the virus. Some isolates failed to infect this plant when other cultivars were used.
Pathogenicity of Fusarium Isolates from Wheat, Rye and Triticale Towards Seedlings and their Ability to Produce Trichothecenes and Zearalenone
Authors: Manka M. , Visconti A. , Chełkowski J. , Baottalico A. 
Published: May 2008

Abstract37 Fusarium isolates (F. culmorum 20, F. graminearum 4, F. avenaceum 3, F. solani 4, and F. equiseti 6 from wheat, rye and triticale) were examined for pathogenicity and tested for zearalenone (F‐2) and trichothecenes production in vitro. Strong pathogens (F. culmorum and F. graminearum) produced deoxynivalenol and 3‐acetyl‐deoxynivalenol and zearalenone in considerable quantities.
Races of Phytophthora megasperma f.sp. glycinea (Phytophthora Rot) Affecting Soybeans in North Alabama
Authors: Collins D. J. , Pacumbaba R. P. , Tsapra V. 
Published: May 2008

Abstract Phytophthora megasperma Drechs. f. sp. glycinea Kuan and Erwin (Pmg) was isolated for the first time from the northern counties of Alabama (MORGAN and MADISON). TWO predominant Pmg races, R2 and R11, were identified by the reactions of standard soybean differential cultivars. Other soil‐borne pathogens isolated from the soil and suspected Pmg‐affected root samples in Morgan, Adadison, and Limestone counties were Pytbium spp., Fusarium ssp., Sclerotium rolfsii, and Rbizoctonia solani. Further study is in progress to obtain a proper assessment of Pmg races in Alabama.
Changes in the Proteins of Bean Leaves Infected With Tobacco Necrosis or Alfalfa Mosaic Viruses
Authors: Szczepański M. , Redolfi P. 
Published: May 2008

AbstractAcidic extracts from TNV and AMV infected “Saxa” bean leaves were electrophoretically examined for protein content. In native conditions of resolution (PAGE) at least three protein bands (PS1–3) not present in the control were found. In denaturing conditions (SDS–PAGE) at least one (PSa), but often two or three such proteins (PSb, c) were found in the same extracts.Chromatographic resolution of proteins on Sephadex G‐100 column resulted in partial purification of the PS‐proteins. Additional, not known before, slow‐migrating protein (PS0) induced by hypersensitive viral infection was discovered in some of the eluted fractions. Both PS0–3 and PSa–c proteins were present in the same fractions. This fact suggests their similarity in molecular weights and/or shapes.
Tomato‐Fusarium oxysporum f. sp. lycopersici Interaction: “in vitro” Analysis of Several Possible Pathogenic Factors
Authors: Scala A. , Bettini P. , Buiatti M. , Bogani P. , Pellegrini G. , Tognoni F. 
Published: May 2008

AbstractThe behaviour of Tomato cultures from known resistant and susceptible cultivars and lines was examined for callus growth on culture media containing increasing concentrations of Fusarium oxysporum f. sp. lycopersici race 1 culture filtrate and phytoalexin synthesis elicited by Fusarium cell wall components. A strict correlation was found between in vivo resistance to the fungus and in vitro hypersensitive response and phytoalexin induction. On the other hand in vitro tolerance to toxic filtrate does not seem in this case a good indicator of in vivo resistance to the pathogen.
Scanning Electron Microscopy of the Influence of Fixation Vehicle Osmolality on Cell Morphology of Spiroplasma, Acholeplasma, and Mycoplasma spp. grown on Agar
Authors: De Leeuw G. T. N. , Van Vught P. A. M. , Samson R. A. , Polak‐Vogelzang A. A. 
Published: May 2008

AbstractYoung Spiroplasma citri, corn stunt spiroplasma, and honey bee spiroplasma colonies fixed in 5% glutaraldehyde in M 199 cell culture medium with 0.25 M sucrose showed elongated mycelium‐like cells which were sometimes branched or helical. In older colonies beaded chains and rounded bodies were formed. Fixation in 6 % glutaraldehyde in distilled water resulted in amorphous masses in which rounded bodies were present. The spiroplasma cells did not remain osmotically active after glutaraldehyde fixation. Acholeplasma laidlawii and Mycoplasma hyorhinis colonies fixed in glutaraldehyde with or without M 199 medium with 0.25 M sucrose showed little difference in cell morphology.
Effects of Salicylate on Virus‐Infected Tobacco Plants
Authors: Pennazio S. , Roggero P. , Gentile Irene Abbattista 
Published: May 2008

AbstractSalicylate watered onto the soil of tobacco plants in pots reduced the antigen accumulation and local lesion growth of tobacco necrosis virus mechanically inoculated on the leaves. It also retarded the growth of the necrotic centres of lesions and, in parallel, inhibited ethylene production from infected leaves. However, the therapeutic index of salicylate was very small and the chemical had to be applied in advance of, or at the same time as virus inoculation to give good levels of resistance. The number of lesions and their rate of appearance were not affected by salicylate. In addition, it did not induce resistance against multiplication, systemic spread or symptom severity in tobacco plants inoculated with a necrotic strain of potato virus Y.These findings suggest that salicylate is not likely to prove useful as polyvalent chemotherapeutic agent.
In vitro Production of Halo Blight Inducing Toxin by Pseudomonas phaseolicola (Burkh.) Dowson
Authors: Bisen P. S. , Sharma Anjana , Agarwal G. P. 
Published: May 2008

AbstractThree pathogenic strains of Pseudomonas phaseolicola (strain 1 and 3 virulent and strain 5 weakly virulent) were tested for their toxic activity. All three strains produced detectable amounts of toxin in vitro. Cultural conditions and length of incubation greatly influenced toxin production. Maximum amount of toxin was produced at 20°C and pH 6.5. Glycerol served as the best carbon source and 1‐cysteine as the best amino acid for toxin production.
The Relationship Between Peroxidase Activity and Resistance to Sphaerotheca fuliginea in Melons
Authors: Reuveni R. , Bothma G. C. 
Published: May 2008

AbstractThe levels of peroxidase activity in leaves of non‐infected melon plants resistant to Sphaerotheca fuliginea (Schl. ex. Fr.) Poll. were considerably higher than those in the leaves of susceptible plants. After infection the ratio of peroxidase activity to that in non‐infected plants reached a value of up to 47.5 in susceptible plants whereas in resistant plants it remained between 1 and 2. Changes in isozyme pattern were investigated by polyacrylamide gel electrophoresis. In non‐infected resistant leaves slowly migrating isozymes were found. Their intensities increased with time following infection. These isozymes were absent in the susceptible leaves but appeared after the leaves had been infected with S. fuliginea. The role of these isozymes in the resistance mechanism is discussed.
Extracellular Enzymes and Nutritional Physiology of Ampelomyces quisqualis Ces., Hyperparasite of Powdery Mildew, in vitro
Authors: Philipp W.‐D. 
Published: May 2008

Abstract In vitro, the powdery’ mildew hyperparasite Ampelomyces quisqualis produced constitutively two groups of extracellular enzymes; β‐glucosidase, β‐N‐acetylglucosaminidase and acid phosphatase possessing unusual high molecular weights (M, about 340 000), and ribonuclease, β‐l→3‐glucanase and α‐l→4‐glucanase representing smaller molecules (M, about 15 000–55 000). As can be concluded from adsorption to Concanavalin A‐Sepharose 4 B, these enzymes are of glycoprotein nature Furthermore, traces of phospholipase could be detected in all of the isolates tested, whereas only phosphorylated carbohydrate components and nucleotides including cAMP as nutrients.The results of these studies suggest that in the biotrophic phase of parasitization A. qwsqualis interferes with energy metabolism, protein synthesis, cell wall synthesis and, possibly, regulation of the host, whereas proteins and membranes remain nearly unaffected. Thus, depletion of the energy reserves of the powdery mildew may be mainly responsible for the degeneration of host ultrastructure which represents the beginning of the necrotrophic phase of parasitization.
The Expression of Race‐Specific Resistance of Wheat Seedlings to Puccinia recondita
Authors: Poyntz B. , Hyde P. M. 
Published: May 2008

AbstractA range of wheat cultivars with resistance factors effective against Puccinia recondita f. sp. tritici was studied to investigate the mode of action and expression of resistance at first and third seedling leaf stages. In most cultivars, resistance to isolate 74/2 resulted in extremely low levels of infection, apparently linked with a predominantly hypersensitive response by the host. In seedlings of cultivars Mans Fundin and Sterna, however, race‐specific resistance was expressed as increased pathogen latent period and intermediate infection levels.
Acquired Resistance in Hypersensitive Tobacco against Tobacco Mosaic Virus, Induced by Plant Cell Wall Components
Authors: Modderman P. W. , Schot C. P. , Klis F. M. , Wieringa‐Brants D. H. 
Published: May 2008

AbstractIsolated cell walls from Nicotiana tabacum L. cv. Xanthi‐nc were partially digested with enzymes present in the fungal preparation cellulase Onozuka R‐10. Released carbohydrate material was separated from the enzymes by gel filtration and fractions were injected into the intercellular spaces of one half of each of several Xanthi‐nc leaves. Two to three days after injection the whole leaves were inoculated with TMV. A large reduction in mean lesion diameter was observed in the injected areas compared with those in untreated tissue.
The Effect of Post Inoculation Treatment with Mineral Oil on TMV Multiplication in Tobacco Leaves and Protoplasts
Authors: White R. F. , Forde S. M. D. 
Published: May 2008

AbstractHalf leaves of N. tabacum dipped into a 0.2 % emulsion of meneral oil 15min after inoculation with tabacco masaic virus (TMV) developed significantly fewer lesion than when not dipped Dipping reduced lesion numbers when applied up to 2½ h after inoculation and multiple dippings were more effective than one. The effect of oil was the same whether the inoculum was whole virus or RNA. Tobacco protoplasts treated with mineral oil contained less virus than untreated protoplasts. The oil probably acted by killing the protoplasts and was effective only when protoplasts were centrifuged through the oil emulsion, When water‐treated leaves were dipped into a TMV solution there was an effect on TMV infection similar to that caused by dipping in oil after TMV inoculation.
Purification, Properties and Serology of Strawberry Mild Yellow‐Edge Virus
Authors: Martin R. R. , Converse R. H. 
Published: May 2008

AbstractOregon isolate My‐18 of strawberry mild yellow‐edge virus (SMYEV) was purified by comminution in liquid nitrogen, extraction in 0.1 M phosphate, 0.01 M DIECA, 1 % thioglycollic acid (pH 7.0) and differential and rate‐zonal density gradient (dg) centrifugation. The resulting ultraviolet‐absorbing dg band (A254 nm), not seen in healthy control preparations, contained isometric, 23 mm‐diameter, virus‐like particles. The partially purified MY‐18 virus was not transmitted to Fragaria vesca by means of membrane‐fed or injected Chaetosiphon fragaefolii. MY‐18 has an in vivo thermal inactivation point between 45 and 50 °C as determined by feeding C. fragaefolii on detached leaves that had been immersed in water for 10 min at various temperatures. In ELISA, rabbit antisera against MY‐18 differentiated between partially purified preparations from root and leaf tissue and between crude root but not crude leaf extracts from healthy and MY‐18‐infected Fragaria. Our data support the generally held hypothesis that SMYEV is a luteovirus. However, comparative ISEM and ELISA tests failed to reveal any serological releationship between MY‐18 and potato leafroll, beet western yellows, legume yellows, pea leafroll, or tobacco necrotic dwarf viruses.
Detection and Comparison of some Ghanaian Isolates of Cacao Swollen Shoot Virus (CSSV) by Enzyme‐Linked Immunosorbent Assay (ELISA) and Immunoelectron Microscopy (IEM) Using an Antiserum to CSSV Strain 1A
Authors: Sagemann W. , Lesemann D.‐E. , Paul H. L. , Adomako D. , Owusu G. K. 
Published: May 2008

AbstractVarious isolates of Cacao Swollen Shoot Virus (CSSV) were detected without difficulty in leaves of Theobroma cacao L. by ELISA and immunosorbent electron microscopy (ISEM) using an antiserum to severe strain 1A. Many isolates were detected with relatively high values at dilutions of 1:30, whereas some other isolates were hardly or not at all detected at this dilution. Strain 1A was detected at dilutions of up to 1: 2560 of crude leaf extracts. All isolates yielding high reactions seem to be serologically closely related to strain 1A. Strains of the mottle‐leaf type (AD 191, AD 196, AD 7, AD 36, AD 135, Kpeve) and others were poorly detected; their relationship to strain 1A is discussed. A close correlation was found between results obtained by ELISA and ISEM.
Non‐Specific Induction of Pisatin and Local Resistance in Pea Leaves by Elicitors from Mycosphaerella pinodes, M. melonis and M. ligulicola and the Effect of Suppressor from M. pinodes
Authors: Yamamoto Y. , Oku H. , Shiraishi T. , Ouchi S. , Koshizawa K. 
Published: May 2008

AbstractThe accumulation of pisatin was induced non‐specifically by elicitors prepared from the high molecular weight fraction (molecular weight: more than 10,000 daltons) of the spore germination fluid of three species of Mycosphaerella‐plant pathogens in pea leaves with epidermis removed, regardless of the pathogenicity of the fungi to pea. Before the elicitation of pisatin synthesis, local resistance to infection by Mycosphaerella pinodes was induced by elicitors again non‐specifically inpea leaves in which wax had been removed from the leaf surface. The substance responsible for local resistance could be extracted with ethylacetate from the elicitor‐containing drop diffusate which was placed on pea leaves. The substance prevented the penetration of M. pinodes through heat‐killed pea epidermis, but did not affect spore germination. The suppressor prepared from the low molecular weight fraction (molecular weight: less than 10,000 daltons) of the spore germination fluid of M.pinodes counteracted the ability of elicitors to induce both phases of resistance mechanisms.
The Control of Fusarium solani f. sp. phaseoli by Fungicide Mixtures
Authors: Ahmed Mussa Ahmed El‐Tayeb 
Published: May 2008

AbstractSix fungicides were used either alone or in binary combination to control Fusarium solani f. sp. phaseoli. Of the three methods of application used, seed treatments and soil drenches were the best, although phytotoxicity was evident in some instances. Application as a seed soak for 1 h proved to be the worst method with most treatments showing signs of phytotoxicity.The results are discussed with reference to the use of fungicide mixtures to control foot rot of beans.
Immunoenzymic Localization of Plant Virus on Aphid Stylets
Authors: Jellison J. 
Published: May 2008

AbstractAn enzyme‐linked antigen distribution assay (Makleret al. 1981) was used to detect and to visualize the location of the lentil strain of pea seed‐borne mosaic virus, a non‐persistently transmitted potyvirus, on dissected vector stylets.
A Leaf Spot of Water Hyacinth Caused by Drechslera spicifera
Authors: Abdel‐Rahim A. M. , Tawfig S. 
Published: May 2008

AbstractIn the present study, corn meal agar was found as the best medium for growth of Drechslera spicifera, a pathogen of water hyacinth.Small water hyacinth plants exhibited a smaller number of lesions/leaf when inoculated with D. spicifera compared with inoculated medium and large plants. However, percentage total diseased area/leaf was almost the same among the different plant sizes.The pathogen did not interfere with the vegetative plant growth, since, both infected and healthy water hyacinth plants of the same age showed similar percentages of new leaf growth.Leaf diffusates of water hyacinth plants significantly reduced conidiospore germination in D. spicifera.
Soybean Mosaic Virus: Vector Specificity and Coat Protein Properties
Authors: O'Connell‐Ziegler P. , Benner H. I. , Hill J. H. 
Published: May 2008

AbstractAphid transmission studies of two soybean mosaic virus isolates have shown that both isolates are transmitted by Myzus persicae. Only one of the isolates is transmitted by Rhopalosiphum maidis. The R. madis non‐transmissible isolate could be transmitted from plants co‐infected with the R. maidis transmissible isolate; aphid acquisition factor did not seem to mediate this transmission. The two isolates could be differentiated by enzyme‐linked immunosorbent assay experiments, but peptide mapping experiments revealed few differences between the isolates.
Response to Gamma Irradiation and Induced Virulent Mutation in Melampsora medusae of Poplars
Authors: Prakash C. S. , Heather W. A. 
Published: May 2008

AbstractWhen the urediniospores of three races of Melampsora medusae, the causal agent of leaf rust of poplars, were exposed to Co60 gamma irradiation (range 100–1000 Gy), there were significant differences in the radiosensitivity of the races as assessed, in vitro, by incubation period to flecking and the uredinial survivability percentage. In race 5A the frequency of mutation to virulence on Populus deltoides cv. T‐173, normally a resistant cultivar, was maximum (1.688 %) at an irradiation dose of 400 Gy. Importance of mutations as source of variability in pathosystems and usefullness of artificially induced mutations in the context of host‐pathogen interactions are discussed.
Die Parasitierung des Bohnenrostes Uromyces appendiculatus var. appendiculatus durch den Hyperparasiten Verticillium lecanii: Untersuchungen zur Wirt‐Erkennung, Penetration und Abbau der Rostpilzsporen
Authors: Grabski G. C. , Mendgen K. 
Published: May 2008

Abstract Hyperparasitism of Uromyces appendiculatus var. appendiculatus by Verticillium lecanii Host Recognition, Penetration and Degradation of Spores Culture filtrates of the hyperparasite Verticillium lecanii contain numerous lytic enzymes. When specific substrates were added to the filtrate, degradation of chitin is increased by a factor of 2,25 and degradation of starch is increased by a factor of 1,5. The degradation of uredo‐ and teliospores of Uromyces appendiculatus var. appendiculatus is documented cytologically. Appressoria‐like structures initiated direct penetration of the spore walls. Additional routes of penetration through the germpores of both sporetypes and the pedicles of the teliospores were observed. Degradation of the spore cytoplasm is described. Sugars on the surface of uredo‐ and teliospores and on hyphae of the hyperparasite were characterized using the gold‐marked lectins Con A and WGA. Their role in the host‐parasite recognition process is discussed.
Cyanogenesis of Hevea brasiliensis during Infection with Microcyclus ulei1)
Authors: Lieberei R. 
Published: May 2008

AbstractEight Hevea species have been shown to be cyanogenic.They all liberated HCN following mechanical tissue injury. Infection of Hevea leaves with conidia of the plant pathogen Microcyclus ulei leads to a large reduction of hydrocyanic acid potential, while only small amounts of HCN are set free from the leaves into the atmosphere. HCN production by infected leaves follows a reproducible pattern with a maximum between 40 and 60 hours after infection.During the entire time of infection free HCN can be detected in the leaves. From leaves of susceptible clones high amounts of HCN are liberated whereas from resistant clones only very little HCN is released. In Hevea infections with M. ulei, cyanogenesis does not lead to defense of the fungal pathogen but impairment of the resistance reaction.
Comparative Studies on Aphid Transmission of the Sudanese Strain of Peanut Stunt Virus
Authors: El Sadiq E. O. , Ahmed A. H. 
Published: May 2008

AbstractThe Sudanese strain of peanut stunt virus was transmitted by Aphis craccivora, Aphis solanella, Myzus persicae and Liaphis erysimi. Of these, A. solanella and L. erysimi were reported for the first time as vectors of peanut stunt virus. A. gossypii, A. solani and Rhopalosiphum maidis failed to transmit the virus. Viruliferous aphids retained the virus for 30 minutes but post‐acquisition starvation beyond 30 minutes resulted in almost complete loss of the virus. A. craccivora transmitted the virus to four consecutive test plants and A. solanella, L. erysimi and M. persicae transmitted the virus to three consecutive test plants. It has been suggested that future research programmes should, include resistance to the virus in the major legume crops and that a crop like lucerne (Medicago sativa) which harbours both the virus and its vectors, should not be introduced in the major peanut‐growing areas of the Sudan.