bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemotherapeutical Elimination of Potato Virus X from Potato Stem Cuttings
Authors: Bittner Heide , Schenk G. , Schuster G. 
Published: May 2008

AbstractPotato virus X was completely eliminated from all infected potato stem cuttings grown in nutrient media containing 0.02 or 0.03 % 2,4‐dioxohexahydro‐1,3,5‐triazine (DHT). When DHT was added to the media in concentrations of 0.01 and 0.005% the efficiency by which the virus was eliminated differed between the varieties tested.The method is less time‐consuming than the generally used meristem (axillary‐) tip culture in combination with chemo‐ or thermotherapy.
The Influence of pH and Temperature on Cellulolytic and Pectolytic Activity ofCylindrocarpon destructans(Zins.) Scholt.
Authors: Strzelczyk E. , Dahm H. , Kowalski S. 
Published: May 2008

AbstractIn studies on the effect of pH and temperature on cellulolytic and pectolytic activity of C.destructans, it was found that the isolates used produced only endoglucanases. The temperature and pH affected the synthesis of these enzymes. Fungi cultured at 26°C produced more of these enzymes than those grown at the two other temperatures. At 10°C, only one isolate produced minute amounts of endoglucanases. None of fungi studied exhibited cellulolytic activity in cultures grown at 20°C. Cellulolytic activity was found only in acidic media (pH 5.0). The fungi studied exhibited higher pectolytic than cellulolytic activity. In the post culture liquids of these organisms, both types of pectolytic enzymes (exo‐ and endo‐PMG) were detected. Different temperature and pH values affected the production of these enzymes differently in various isolates.
Differential Influence of Ectomycorrhizae on Plant Growth and Disease Resistance in Pinus sylvestris Seedlings
Authors: Chakravarty P. , Unestam T. 
Published: May 2008

AbstractThe influence of Laccaria laccata, Hebeloma crustuliniforme, and Pisolithus tinctorius mycorrhizae and a mixture of naturally occurring mycorrhizae on the resistance of Pinus sylvestris seedlings to attack by Fusarium moniliforme and Rhizoctonia solani was investigated periodically during an entire year under greenhouse conditions following inoculation with both mycobiont and pathogen. Using artificial root substrate the seedlings were provided with a balanced butlow nutrient supply. Seedling growth (dry weight) as well as short‐root formation was stimulated to different extents depending on the mycobiont species; in addition, the degree of stimulation varied over the year. Parasitized plants were more stimulated, than nonparasitized ones. Disease severity and plant mortality caused by either pathogen were drastically reduced in the presence of the mycorrhizal fungi, even before mycorrhiza formation. All mycorrhizae, except the association with Hebeloma, remained highly protective throughout the year; with Hebeloma it remained protective for only about 3 months. Growth stimulation or mycorrhiza frequency was not always correlated with the level of protection; e.g. Hebeloma protected withoutstimulating growth. Two types of protection apparently exist, one related to and another unrelated to growth stimulation. Mycorrhizal fungi had little or no antagonistic effects on fungal pathogens in vitro.
Experimental Transmission of Plum Pox Virus (PPV) to Prunus Mahaleb and Prunus avium
Authors: Dosba F. , Maison P. , Lansac M. , Massonie G. 
Published: May 2008

AbstractSharka caused by plum pox virus (PPV) is a disease spread in France since 1970, and causing severe damages essentially on apricot but also on plums and peach.Cherry is generally considered as not infected by PPV. Experimental transmissions by chip budding or aphids allowed to show that 3 isolates of PPV can multiply inside three cherry rootstocks (P. Mahaleb cv.‘SL 64′, P. avium cv.‘F 12‐1′, and P. avium*P. pseudocerasus cv. ‘Colt') (Tables 1 and 2).But generally, the virus remained localized to the infection site and disappeared quickly (Table 3). Typical symptoms of chlorotic ringspot or vein clearing are also limited to the leaves probed by the aphids.The fact that no translocation was detected is discussed.
The Influence of Temperature on Phytophthora infestans (Mont.) de Bary
Authors: Sujkowski L. S. 
Published: May 2008

AbstractThe influence of temperature on the growth rate, sporulation density and zoospore release of Phytophthora infestans, cultivated on rye agar, has been studied.Temperature significantly influenced all the features of the fungus mentioned above. The highest yield of sporangia per 1 cm2 of aerial mycelium occurred at 24°C while the highest percentage of sporangia releasing zoospores was observed when the fungus was grown at 15 °C. When considering the size of the fungal colony the highest production of sporangia was obtained at 20°C.It was concluded that the temperature at which the fungus was cultured predetermined the way it germinated.
Lectins Specificity to Pathogenesis of Fusarium oxysporum f. sp. vasinfectum
Authors: Abd‐El‐Rehim M. A. , Abou‐Taleb E. M. , Tohamy A. 
Published: May 2008

AbstractLectins of cotton were isolated from either resistant or susceptible seed cultivars. In agar‐gel double diffusion tests, positive reactions took place between lectins of cotton cultivars and the antisera of their corresponding wilt Fusaria. The number of precipitin bands correlated with the degree of susceptibility of the tested cultivars. On the other hand, no visible reaction was detected when these antisera were subjected to react with either the resistant host or nonhost lectins.
Viruses Associated with a Mosaic Disease of Crotalaria juncea in Nigeria
Authors: Ladipo J. L. 
Published: May 2008

AbstractCowpea mosaic virus was one of the viruses isolated from Crotalaria juncea showing mosaic, distortion and puckering symptoms. The virus induced local necrotic lesions in Canavalia ensiformis, Cassia occidentalis, Nicotiana debneyi, N. occidentalis, N. repanda and N. sylvestris and some cultivars of Phaseolus vulgaris 4–6 days after inoculation. It induced local chlorotic spots, which later became necrotic, as well as systemic chlorotic spots, vein chlorosis, distortionand puckering in Chenopodium amaranticolor.Sap from systemically infected cowpea cv. ‘C20‐55’was infective after dilution to 10−5 but not 10−6, after 10 min at 65°C but not 70°C, or after 4 days, but not 5 days, at a room temperature of 15–25°C. Infectious virus was recovered from fresh reproductive tissues of infected cowpea cvs ‘C20‐55’and ‘Ife Brown’ plants but not after dehydration.
Systemic Invasion of Immature Sweet Cherry Fruit by Pseudomonas syringae pv. morsprunorum Through Blossoms1
Authors: Roos Isabel M. M. , Hattingh M. J. 
Published: May 2008

AbstractCherry blossoms inoculated with a rifampicin‐resistant strain of Pseudomonas syringae pv. morsprunorum died or gave rise to fruits containing necrotic spots at or near the blossom ends. Scanning electron microscopy of developing fruits indicated that the pathogen had invaded the entire pericarp, including the endocarp. Bacteria also spread to the fruit stalk and, to a lesser extent, to the spurs. Mesocarp cells below the lesion collapsed. Infected fruit, stalks, and spurs contained, respectively, ca. 109, 107, and 102 colony forming units of P. syringae pv. morsprunorum as determined by a dilution plate method on an agar medium supplemented with 50 μg/ml rifampicin. This is the first report of systemic spread of P. syringae from blossoms to developing fruit of a deciduous crop.
MLO‐Associated Decline of Alnus glutinosa, Populus tremula and Crataegus monogyna
Authors: Seemüller E. , Lederer W. 
Published: May 2008

AbstractIn the Heidelberg area of southwestern Germany declining trees of Alnus glutinosa (L.) Gaertn. and Populus tremula L. as well as stunting shrubs of Crataegus monogyna Jacq. were observed. In all 3 species mycoplasmalike organisms, which appear to be the causal agents of the disorders, were detected by fluorescence and electron microscopy. The diseases of alder and aspen seem to be lethal while the hawthorn apparently is less affected.
Transmission of Three Viroids Through Seed and Pollen of Tomato Plants
Authors: Kryczyński S. , Paduch‐Cichal E. , Skrzeczkowski L. J. 
Published: May 2008

AbstractThe severe strain of potato spindle tuber viroid (s‐PSTV) as well as chrysanthemum stunt (CSV) and cucumber pale fruit (CPFV) viroids were found to be transmitted through seed and pollen of the tomato cvs. Rutgers and Najwcześniejszy. Plants pollinated with a pollen infected with any of these three viroids became systematically infected. Plant, fruit and seed symptoms of viroid infection were noted on sap‐ and pollen‐inoculated plants and the yield of these plants was reduced.Tomato cv. Rutgers plants grown from infected seeds were symptomless although all three viroids were detected in these plants by bioassay and by electrophoresis on 5% polyacrylamide gel.When DNA complementary to s‐PSTV RNA was used for a direct viroid detection in seed samples by spot hybridization technique it hybridized not only with s‐PSTV RNA but also with CSV RNA as well as with CPFV RNA.
Hypersensitive Reaction in Petunia
Authors: Nicoud S. , Dumas E. , Cornu A. , Gianinazzi S. 
Published: May 2008

AbstractIntercellular fluid (IF) extracted from the apoplastic leaf spaces of Petunia contained up to 6 new soluble proteins, called d proteins (d0 to d5). Characterisation of the d proteins has shown that they can be divided into groups and show a genetic variability similar to the PR(b) proteins from Nicotiana. d protein patterns from Petunia interspecific hybrids clearly show that the determinant for the d proteins in sexually transmitted as is the case for b proteins in Nicotiana. d‐protein induction in TMV‐SM1 infected Petunia leaves is discussed in relation to the resistance to infection shown by cultivars and hybrids of Petunia.
Antibiosis of Streptomyces griseus Against Colletotrichum lindemuthianum
Authors: Tu J. C. 
Published: May 2008

Abstract Streptomyces griseus produces an antibiotic substance against Colletotrichum lindemuthianum because, in dual culture on potato dextrose agar (PDA), a large inhibitory zone was formed between the colonies of S. griseus and C.lindemuthianum. When S. griseus was placed adjacent to a colony of C. lindemuthianum in PDA, S.griseus grew poorly in PDA but it thrived and sporulated profusely when it came in contact with a colony of C. lindemuthianum indicating that S.griseus might require some essential nutrients from C.lindemuthianum. Scanning electron microscopy showed that hyphae of S.griseus in contact with C.lindemuthianum produced appressorium‐like swellings or simply grew on the hyphal surface of C.lindemuthianum. Internal parasitism was evidenced by the presence of hyphae and conidia of the mycoparasite inside the host hyphae. Internal parasitism resulted in formation of several blebs. Cell walls of the parasitized hyphae degenerated having a sponge‐like texture. The blebs broke off and left rounded holes on the hyphae.
Further Studies on a Virus Causing a Green Mosaic Disease of Eggplant in Nigeria
Authors: Ladipo J. L. , Lesemann D.‐E. , Koenig R. 
Published: May 2008

AbstractA virus reported earlier to cause a green mosaic disease of eggplant in Nigeria was studied in more detail. Its filamentous particles with a normal length of 820 nm reacted in immunoelectron microscopical tests strongly with the homologous antiserum and less strongly with antisera to dioscorea green banding mosaic, groundnut eyespot, zucchini yellow mosaic viruses and to a tomato potyvirus isolate from Taiwan. No reactions were seen with antisera to 25 other potyviruses. Several new host plants were identified. Infected cells contained cylindrical inclusions with scrolls and short curved laminated aggregates and clusters of small vesicles with electron‐dense content. Host range and serological reactivities differentiate the virus for which the name eggplant green mosaic virus is suggested from all potyviruses so far known.
Enzyme‐Linked Immunosorbent Assay (ELISA) of a Coryneform Isolated from Ratoon Stunted Sugarcane
Authors: Pillay D. , Oellermann R. A. 
Published: May 2008

AbstractAn enzyme‐linked immunosorbent assay (ELISA) was developed for the coryneform bacterium isolated from ratoon stunted surgarcane. Parameters governing the ELISA were optimized. These included antibody coating concentration, conjugate concentration and diluent, antigen diluent, the washing procedure, incubation temperature for sample and conjugate, pH and time. The level of detectability of the cultured bacterium by the ELISA was ≥ 1 × 104 Zellen · ml‐1.
Small RNAs Originating from Symptomless and Damaged Spruces (Picea spp.)
Authors: Beuther E. , Köster S. , Loss P. , Schumacher J. , Riesner D. 
Published: May 2008

AbstractRibonucleic acids were extracted from needles of symptomless and damaged spruces (Picea spp.). Trees from three locations of different altitudes in Nordrhein‐Westfalen were taken for sampling. The samples were collected from the same individual trees at different times during the growing seasons of the years 1984–1986.Small RNAs (Mr <300 000) were analyzed by a two‐dimensional gelelectrophoresis. The aim was to detect “disease associated” RNAs by a comparison of the RNA‐patterns of symptomless and damaged spruces. A RNA of about 450 nucleotides was a strong candidate, though it was found in needles of both damaged and symptomless trees. The concentration of the RNA450 is dependent on the season, the needle age, and the location of the tree. In damaged trees the level of the RNA450 ishigher than in symptomless trees. The RNA450 was found to be an endogeneous RNA, which indicates both the developmental state of the needle, and an interference with the development by the damage already at the early level of RNA metabolism.
RNA/cDNA Hybridization and Infectivity Tests Suggest that Barley Yellow Mosaic Virus Isolate M has a Bipartite Genome
Authors: Koenig R. , Huth W. 
Published: May 2008

AbstractNorthern blot analysis with random‐primed cDNAs revealed that RNAs 1 and 2 of barley yellow mosaic virus (Ba YMV) isolate M have no extensive base sequence homologies. Both RNAs are needed for infection. RNA 2 is therefore neither a subgenomic nor a, satellite RNA, but rather an essential part of the viral genome. Ba YMV isolate M has thus a bipartite genome.
Electron Microscopic Studies of Spruce Needles in Connection with the Occurrence of Novel Forest Decline
Authors: Jung Georg , Wild Aloysius 
Published: May 2008

AbstractNeedles of four spruce trees showing different degrees of novel kinds of forest decline were investigated by electron microscopy. Green needles appearing at least superficially still intact were selected for the present investigation. Most of the mesophyll appeared to be undamaged. However, groups of atypical mesophyll cells were found close to the endodermis or the hypodermis. The chloroplasts of the apparently damaged cells were particularly affected. Changes in the matrix of the chloroplasts, i.e,. increased affinity to osmium, occurrence of extensive nests of plastoglobuli, as well as damage to the membranes, i.e. lesions in the envelope and abnormal thylakoid membranes, were observed. Signs of decomposition of other cellular structures including mitochondria were also detectable. There appeared to be a close correlation between the degree of damage at the whole tree level and the degree of damage occurring at the cellular level. It is concluded that particularly the lipids and the proteinsof, the membranes are affected by anthropogenic air pollutants and natural stressors. The altered membrane structure may for instance cause abnormal osmotic conditions for the cellular compartments and may impair transport processes and thus lead to lossof function not only of the cells but also of the whole needle.
Intracellular Localization of the Systemic Fungicide Triadimenol in Phytopathogenic Fungi
Authors: Hippe Sigrun , Hermanns Monika 
Published: May 2008

AbstractThe intracellular localization of the radioactively labelled fungicide (3H)triadimenol A in the in vitro grown sporidia of Ustilago avenae and in the in vivo cultured powdery mildew (Erysiphe graminis f. sp. hordet) on barley (Hordeum vulgare) is described. The specimens were prepared by low temperature techniques: shock freezing, freeze substitution and embedding in Spurr's low viscosity resin. The localization of the fungicide was achieved by means of conventional electron microscopic autoradiography. The available experimental data allow a first qualitative analysis of the distribution of silver grains on freeze substituted sporidia of U. avenae and the infection structures of Erysiphe graminis f. sp. hordei. Concerning U. avenae the fungicide is detected preferentially over the vacuoles, the cytoplasm, and the cell walls after a six month exposure. The host pathogen system powdery mildew on barley exhibits an accumulation of silver grains in the host cell wall adjacent to the infection site and the papillae whereas decisively fewer grains occur inside the haustoria. Apart from this general localization pattern the haustoria show ultrastructural changes caused by the fungicide treatment: vesiculation and collapse of the sheath membrane as well as a diffuse appearance of the haustorial cytoplasm. Around the haustoria an aggregation of host cytoplasm material is observed.
Fluorescence and Electron Microscopy of Cynodon dactylon Affected with a White Leaf Disease in the Sudan
Authors: Dafalla G. A. , Cousin M. T. 
Published: May 2008

AbstractA disease characterized by complete chlorosis of plant foliage was recently observed in Cynodon dactylon L. naturally growing in central Sudan. Severely affected plants were stunted with short internodes and small inward folded leaves. Examination of sections from paraffin embedded leaf and rhizome fractions, stained with a DNA‐binding fluorochrome Bisbenzimid H 33258, and observed in a fluorescent microscope revealed abnormal amounts of DNA material in the phloem sieve tubes of diseased plants. More intense fluorescence was also observed in the xylem region and was shown to be due to the presence of a rod‐shaped bacterium. No such anomalies were observed in healthy plants. Electron microscopy of ultrathin sections prepared from phloem zones, reacting with fluorescence in light microscopy revealed the presence of pleomorphic prokaryotes in the sieve tube elements of such zones. No helical forms were observed in semi‐thin sections from the same plant material, suggesting the MLO nature of these prokaryotes.
In vitro Selection of Strains of Phytophthora cactorum Resistant to Metalaxyl
Authors: Utkhede R. S. , Gupta V. K. 
Published: May 2008

AbstractIsolates of Phytophthora cactorum resistant to the systemic fungicide metalaxyl were obtained by exposing them to sequentially increased concentrations of metalaxyl. A linear relationship was observed between the concentrations of metalaxyl and percentage inhibition of mycelial growth of P. cactorum. The stability of metalaxyl‐resistant isolates 150R and 250R was confirmed after six serial transfers on corn meal agar without fungicide. The in vitro metalaxyl‐resistant isolate (Ph10) was less aggressive on apple rootstocks compared with the Ph07 isolated from metalaxyl‐treated trees and the Ph03 isolated from untreated trees. Metalaxyl‐resistant and sensitive isolates remained sensitive to the chemically unrelated fungicide fosetyl‐Al at high concentration (600 μg/ml), to mancozeb, and to a mixture of metalaxyl + mancozeb. Significant differences in resistance to metalaxyl existed among P. cactorum field isolates.
Preliminary Investigations about the Mode of Transmission and Spread of Xanthomonas campestris pv. graminis on Forage Grasses
Authors: Leyns F. , De Cleene M. , Van Bogaert G. , Van de Wiele A. , De Ley J. 
Published: May 2008

AbstractExtensive studies showed that no disease was caused when seeds of different forage grasses were inoculated with Xanthomonas campestris pv. graminis. The disease could easily be induced by infecting the plants in the root system, leaves or flower. The inoculation site in the leaf proved to be of vital importance for the development of the disease. Wilting symptoms were quickly induced when the pathogen was inoculated near the leaf base. Plants in root‐contact with diseased plants showed disease symptoms. It is not known whether these symptoms were caused by the bacteria or by toxins released by nearby diseased plants. Cross inoculation trials on different grass varieties revealed that different pathovars exist in the group of xanthomonads, pathogenic to forage grasses. Some have a broad host range whereas others are more limited to a single plant genus. Field trials suggest that in Belgian climatic conditions, the losses caused by bacterial wilt are rather limited.
A Simple Procedure for the Purification and Antiserum Production of Bean Yellow Mosaic Virus
Authors: Makkouk K. M. , Katul L. , Rizkallah A. 
Published: May 2008

AbstractA simple procedure was developed to purify bean yellow mosaic virus from infected faba bean. The procedure included clarification of tissue homogenate by 25% chloroform followed by low‐speed centrifugation, virus concentration by polyethylene glycolprecipitation and further purification by agarose‐acrylamide gel electrophoresis. The partially purified virus preparation was electrophoresed in 0.5% agarose‐2% acrylamide gel for 4 h. Gel bands containing the virus were collected, homogenized, and mixed (1:1) with Freunds adjuvant. Four weekly intramuscular injections and a booster injection four weeks after the fourth injection were given to a rabbit. Antisera collected from the first five bleedings produced high A405 readings in ELISA (0.47,5–0.790) with virus‐infected faba bean leaves and low readings (0.030–0.065) with healthy tissue. Plates were coated with 5μg/ml of gammaglobulins (IgG) fractionated from the different bleedings of the antiserum prepared and a 1: 1000 dilution ofthe IgG from the third bleeding conjugated to alkaline phosphatase was used.
Peroxidase Activity in Leaves of Wheat Cultivars Differing in Resistance to Erysiphe graminis DC.
Authors: Patykowski J. , Urbanek H. , Kaczorowska T. 
Published: May 2008

AbstractThe peroxidase activities in leaves from resistant and susceptible cultivars of wheat infected and non‐infected by Erysiphe graminis DC were studied. In non‐infected wheat, soluble and ionic bound peroxidase activity level was found to be higher in the resistant cultivar than that in the one susceptible to Erysiphe graminis DC. After infecting wheat leaves with Erysiphe graminis DC a remarkable increase in the activity of soluble and ionic bound peroxidases was detected 5 days after inoculation only in the resistant cultivar. In the susceptible cultivar a high increase in the activity of the soluble and ionic bound peroxidases occurred only 15 days after inoculation.Using ion exchange chromatography four peroxidase fractions were obtained from infected susceptible and resistant cultivars as from non‐infected ones. The fraction II in non‐inoculated resistant cultivars was much higher than that in the susceptible one. This fraction increased after inoculation in both cases reaching a higher level in resistant cultivars. Fraction I was higher in the susceptible cultivar.Electrofocusing profiles of peroxidase from the susceptible and resistant cultivar differed from one another. New peroxidase bands after inoculation appeared only in the resistant cultivar.
Conditions for Efficient Isolation and Regeneration of Protoplasts from Fulvia fulva
Authors: Harling R. , Kenyon L. , Lewis B. G. , Oliver R. P. , Turner J. G. , Coddington A. 
Published: May 2008

AbstractA procedure for producing high yields and high regeneration frequencies of protoplasts from Fulvia fulva is described. This procedure was devised by systematic trials of various parameters, such as culture age and osmotic support, which are known to affect protoplast yield and regeneration. Mycelium from liquid cultures of 24–48 h, incubated with Novozym 234 in buffered 1.0 M MgSO4, gave the best conditions for protoplast release. Regeneration frequencies up to 50% were obtained with a complete medium containing 0.8 M sucrose for osmotic support.