scholarly journals A New Biotype of Phaeosphaeria sp. of Uncertain Affinity Causing Stagonospora Leaf Blotch Disease in Cereals in Poland

Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 113-113 ◽  
Author(s):  
E. Reszka ◽  
E. Arseniuk ◽  
A. Malkus ◽  
K. R. Chung ◽  
N. R. O'Neill ◽  
...  
Keyword(s):  
Its Region ◽  
Nucleotide Difference ◽  
Opposite Mating Type ◽  
Disease Symptoms ◽  
Phaeosphaeria Nodorum ◽  
Molecular Comparison ◽  
Beta Glucosidase ◽  
Average Size ◽  
Moderately Resistant ◽  
Extra Nucleotide

A new Phaeosphaeria sp. biotype was isolated from winter ryes in Poland during 1995. Two isolates, Sn23-1 and Sn48-1, were obtained from diseased leaves of cvs. Motto and Dańkowskie, respectively. The rye Phaeosphaeria sp. represented by isolate Sn48-1 has similar pycnidiospore morphology and induces disease symptoms in cereals similar to Phaeosphaeria nodorum, the causal agent of Stagonospora nodorum blotch disease (4). The pathogen (Sn48-1) produces hyaline, cylindrical pycnidiospores that are mostly three-septate and measure 12.8 to 23.7 × 2.1 to 3.2 μm (average size = 16 × 2.6 μm) on water agar. A molecular comparison of several genes in isolates Sn23-1 and Sn48-1 revealed that the rye Phaeosphaeria sp. was different from P. nodorum. In the conserved alpha-box sequence (1,93 bp) of the MAT1-1 gene, a four nucleotide difference occurred between the wheat-biotype P. nodorum and isolates Sn23-1 and Sn48-1 (GenBank Accession Nos. AY072933 and AF322008). In addition, the length of the internal transcribed spacer (ITS) region of the nuclear rDNA was the same for the wheat-biotype P. nodorum and the two rye Phaeosphaeria sp. isolates. However, a six nucleotide discrepancy was found in the ITS region (GenBank Accession Nos. U77362 and AF321323). The beta-glucosidase (bgl1) and beta-tubulin (tubA) genes differ in length between the wheat-biotype P. nodorum and two rye Phaeosphaeria sp. isolates (2,3). The main difference was due to the intron sizes of these two genes. One extra nucleotide was found in the intron2 of the bgl1 gene (GenBank Accession Nos. AY683619 and AY683620) and the intron1 of the tubA gene (GenBank Accession Nos. AY786337 and AY786331), respectively, in these two rye Phaeosphaeria sp. isolates. Disease severity on the fifth leaf (GS15) of Polish wheat (Alba, Begra, and Liwilla), triticale (Bogo and Pinokio), and rye (Zduno) cultivars was assessed with one (resistant) to nine (susceptible) scales 14 days after inoculation. Aggressiveness of wheat-biotype P. nodorum isolate Sn26-1 and rye Phaeosphaeria sp. isolate Sn48-1 was significant (P < 0.01) in five cultivars except in the moderately resistant wheat cv. Liwilla. The rye Phaeosphaeria sp. isolate Sn48-1 severely affected Polish rye Zduno (8.3) and two triticale cultivars (6.5), while the infection by isolate Sn26-1 was moderate (3–4). On the contrary, the wheat-biotype P. nodorum isolate Sn26-1 was more aggressive on wheat (4.1 on moderately resistant Alba and 6.2 on highly susceptible Begra) than the rye Phaeosphaeria sp. isolate Sn48-1, which had a scale of 2.2 and 4.3, respectively. Under laboratory conditions, the rye isolate Sn48-1 was able to cross with the wheat-biotype P. nodorum isolate Sn26-1 that has an opposite mating-type (MAT1-2) gene, but few viable ascospores were produced (1). References: (1) P. C. Czembor and E. Arseniuk. Mycol. Res. 104:919, 2000. (2) A. Malkus et al. FEMS (Fed. Eur. Microbiol. Soc.) Lett. 249:49, 2005. (3) E. Reszka et al. Can. J. Bot. 83:1001, 2005. (4) M. J. Richardson and M. Noble. Plant Pathol. 19:159, 1970.

scholarly journals First Report of Internal Black Rot Caused byNeoscytalidium dimidiatumonHylocereus undatus(Pitahaya) Fruit in Israel

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1513-1513 ◽  
Author(s):  
D. Ezra ◽  
O. Liarzi ◽  
T. Gat ◽  
M. Hershcovich ◽  
M. Dudai
Keyword(s):  
Its Region ◽  
Stem Canker ◽  
Brown Spot ◽  
Black Rot ◽  
Post Inoculation ◽  
Single Spore ◽  
Flower Opening ◽  
Disease Symptoms ◽  
First Report ◽  
Β Tubulin

Pitahaya (Hylocereus undatus [Haw.] Britton & Rose) was introduced to Israel in 1994, and is grown throughout the country. In the summer of 2009, fruit with internal black rot was collected from a field in central Israel. Symptomatic tissue from the black rot was placed on potato dextrose agar (PDA) plates amended with 12 μg/ml tetracycline and incubated at 25°C for 3 days. A dark, gray to black, fast-growing fungus was isolated from all samples (10 fruits). For identification, single-spore cultures were grown on PDA at 25°C for 5 days, and colonies with gray to black, wooly mycelium were formed. The mycelia were branched and septate (4 to 8 μm wide). The arthroconidia were dark brown, thick-walled, and one-celled, 6.3 to 14.2 × 2.0 to 4.5 μm (n = 5), and ovate to rectangular. Based on these characteristics, the fungus was identified as Neoscytalidium dimidiatum (Penz.) Crous & Slippers (1). The internal transcribed spacer (ITS) region of rDNA and β-tubulin gene were amplified using ITS1 and ITS4, T121 (2), and Bt1b (3) primers, respectively, and then sequenced (GenBank Accessions KF000372 and KF020895, respectively). Both sequences were identical to sequences previously deposited in GenBank. The ITS (561 bp) and β-tubulin (488 bp) sequences exhibited 99% and 100% identity, and 100% and 84% coverage, respectively, to N. dimidiatum (JX524168 and FM211185, respectively). Thus, the results of the molecular identifications confirmed the morphological characterization. To establish fungal pathogenicity and the mechanism of infection, 60 flowers in a disease-free orchard were marked to form three different treatments (15 flowers per treatment): inoculations of the flower tube by inserting PDA plugs (0.5 × 0.5 cm) from a 5-day-old culture to the base of the flower, inoculations of the flower stigma by placing the fungus plug on intact, or pre-wounded flower stigma. The wounds were made by scratching the stigma with a sterile scalpel. For each treatment, five additional flowers were used as negative controls in which the PDA plugs did not contain any fungus. All flowers were hand-pollinated and left to grow for a month until the fruit had ripened. Only flowers inoculated by insertion of the fungus into the flower tube developed black rot in the fruit (8 of 15 fruit) 3 to 4 weeks post inoculation, suggesting involvement of the flower tube in the mechanism of infection. All other treatments and controls failed to develop any detectable disease symptoms. N. dimidiatum was reisolated from the rot, fulfilling Koch's postulates. Flowers with wounded stigma developed significantly smaller fruit. Interestingly, diseased fruit changed color about a week before ripening from the flower opening downwards, whereas healthy fruit changed color from the attachment point to the stem upwards. These results indicate that N. dimidiatum is the pathogen of pitahaya internal black rot disease. Recently, this pathogen was reported to cause brown spot disease and stem canker disease of pitahaya in China (4) and Taiwan (5), respectively. To date, the disease can be detected in all orchards in Israel, with up to 50% of the fruit being infected. Since the disease symptoms of the Israeli isolate are located in the fruit, the commercial loss due to pathogen attack is significant. To our knowledge, this is the first report of internal black rot caused by N. dimidiatum on pitahaya fruit in Israel.References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) K. O'Donnell and E. Cigelnik. Mol. Phylo, Evol. 7:103, 1997. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microiol. 61:1323, 1995. (4) G. B. Lan and Z. F. He. Plant Dis. 96:1702, 2012. (5) M. F. Chuang et al. Plant Dis. 96:906, 2012.

Evaluating faba beans for resistance to ascochyta blight using detached organs

2000 ◽  
Vol 40 (5) ◽  
pp. 707 ◽  
Author(s):  
S. Kohpina ◽  
R. Knight ◽  
F. L. Stoddard
Keyword(s):  
Ascochyta Blight ◽  
Good Condition ◽  
Field Trials ◽  
Experimental Conditions ◽  
Susceptible Population ◽  
Disease Symptoms ◽  
Plant Parts ◽  
Cultural Conditions ◽  
Faba Beans ◽  
Moderately Resistant

Detached-organ techniques were developed, using either individual leaves or stem segments with attached leaves, for use in genetic studies on resistance to ascochyta blight in faba beans. A single isolate of Ascochyta fabae, A26, was used to infect the highly resistant population ILB 752, moderately resistant cultivar Fiord and highly susceptible population NEB 463. Cultural conditions were established that maintained the detached organs in good condition for more than the 10 days required for disease symptoms to be expressed. Detached organs were scored for presence, number and size of lesions and also for number of lesions bearing pycnidia. Spore suspensions of 5 x 102 to 2 x 106 per mL were used, with 5 x 104 providing as much infection as greater concentrations. Leaves and stems were taken from 3-, 5- or 7-week-old plants. Younger plant parts were more susceptible than older ones and plants aged 3–5 weeks provided adequate material for the tests. The susceptibility of the 3 accessions in these experimental conditions followed the order expected from field trials.

scholarly journals Diversidad de comunidades fúngicas aisladas de tejidos sintomáticos de la uvilla (Physalis peruviana) en los Andes Ecuatorianos

2019 ◽  
Vol 40 (2) ◽  
pp. 77-86
Author(s):  
Wagner Chaves Acuña
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Microbial Culture ◽  
Disease Symptoms ◽  
Physalis Peruviana ◽  
Rdna Sequencing ◽  
Foliar Tissue ◽  
First Time ◽  
Field Plots ◽  
Cape Gooseberry

We used microbial culture specific methods to assess the occurrence and diversity of fungal communities inhabiting symptomatic foliar tissue of Cape gooseberry (Physalis peruviana) at four different field plots in the northern Ecuadorian Andes. We categorized the isolated fungi based on their morphological characteristics and subsequently identified them through rDNA sequencing of the ITS region. We recovered 75 ascomycetous isolates which represented 13 genera, revealing a total of 20 taxa. We found most isolates recovered from necrotic and straw-colored tissues to belong to the genus Alternaria, while other fungal taxa frequently found were Epicoccum, Diaporthe, and Xylaria. To our knowledge, this is the first study to report the mycobiota associated to P. peruviana plants showing disease symptoms, from which we record 2 new genera of fungi for the first time in Ecuador. Our results are expected to provide useful information for future assessments of biological control on tropical commercial.

scholarly journals A Severe Microsporidian Disease in Cultured Atlantic Bluefin Tuna (Thunnus thynnus L.)

2021 ◽  
Author(s):  
Alejandro López-Verdejo ◽  
Francisco E. Montero ◽  
Fernando De la Gándara ◽  
Miguel A. Gallego ◽  
Aurelio Ortega ◽  
...  
Keyword(s):  
Polar Filament ◽  
Morphological Characteristics ◽  
Single Layer ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna ◽  
Microsporidian Species ◽  
Molecular Comparison ◽  
Severe Pathology ◽  
Average Size

Abstract One of the most promising aquaculture species is the Atlantic bluefin tuna ( Thunnus thynnus ) with high market value; disease control is crucial to prevent and reduce mortality and monetary losses. Microsporidia Balbiani, 1882 (Fungi) are a potential source of damage to bluefin tuna aquaculture. A new microsporidian species is described from farmed bluefin tunas from the Spanish Mediterranean. This new pathogen is described in a juvenile associated with a highly severe pathology of the visceral cavity. Whitish xenomes from this microsporidian species were mostly located at the caecal mass and ranged from 0.2 to 7.5 mm. Light and transmission electron microscopy of the spores revealed mature spores with an average size of 2.2 × 3.9 μm in size and a polar filament with 13–14 coils arranged in one single layer. Phylogenetic analysis clustered this species with the Glugea spp. clade. The morphological characteristics and molecular comparison confirm that this is a novel microsporidian species, Glugea thunni sp. nov. The direct life cycle and the severe pathologies observed makes this parasite a hard risk for bluefin tuna cultures.

scholarly journals PHYLOGENY AND MORPHOLOGY OF NEODIDYMELLIOPSIS IRANENSIS SP. NOV., CAUSING DEAD BRANCHES OF CITRUS IN IRAN

2021 ◽  
Vol 56 ◽  
pp. 79-93
Author(s):  
Parisa SOLEIMANI ◽  
Keyword(s):  
Its Region ◽  
Morphological Features ◽  
The Other ◽  
Phylogenetic Position ◽  
Test Results ◽  
Disease Symptoms ◽  
Citrus Production ◽  
Pure Cultures ◽  
Morphological Differences ◽  
A New Species

Citrus plants, which are mostly cultivated in the southern tropical area of the country, are one of the important economic crops in Iran. Branch canker and dieback of citrus is an ongoing problem for citrus growers located in these areas and has imposed irreparable damage to the citrus production in this region in recent years. Disease symptoms consisted of the blight of vigorously growing shoots and dieback of the branches and rootstock trunks. This study aimed to characterize the citrus dieback pathogen morphologically and phylogenetically, and the species Neodidymelliopsis iranensis Soleimani & Goudarzi, sp. nov., is described and illustrated here. Isolates were derived from collected citrus samples with dieback symptoms. After preparing pure cultures from single spores on oatmeal agar and malt agar, the morphological features of the species were described and their pathogenicity was confirmed on lime (Citrus aurantifolia). Morphologically N. iranensis is easily separated from the other species of Neodidymelliopsis by the size of pycnidia, conidia septation, and NaOH test results. The morphological differences between our isolates and the other known species of Neodidymelliopsis were strongly supported by a multi-locus phylogenetic analysis based on the ITS region, and LSU, RPB2, and TUB2 genes. In the reconstructed phylogenetic tree, N. iranensis formed a well-supported clade with other Neodiddymelliopsis species in the Didymellaceae family, but was separated from all other Neodiddymelliopsis species. The distinct phylogenetic position is supported by differences in morphological features. Consequently, the specificity of the morphological and phylogenetical features of the collected isolates has convinced us to describe Neodidymelliopsis iranensis as a new species.

scholarly journals Outbreak of Powdery Mildew Caused by Erysiphe cruciferarum on Spider Flower (Cleome hassleriana) in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (9) ◽  
pp. 963-963 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
Powdery Mildew ◽  
Its Region ◽  
Herbarium Specimens ◽  
Pathogenicity Test ◽  
Public Park ◽  
Potted Plants ◽  
Powdery Mildews ◽  
Erysiphe Cruciferarum ◽  
Average Size ◽  
Germ Tubes

Spider flower (Cleome hassleriana L. [synonym = C. spinosa]) is used as a tall border in parks and gardens worldwide. During July 2008, severe outbreaks of a powdery mildew were observed in a public park in Torino (northern Italy). Leaves were covered with dense, white hyphae and conidia, especially on the adaxial surface. Hyphae were also present on petioles and fruits, but not on petals and stems. As the disease progressed, infected leaves turned chlorotic, curled, and wilted. Conidia were hyaline, cylindrical, single, and measured 31.1 to 48.2 × 12.9 to 17.6 μm (average 37.1 × 15.6 μm). Germ tubes terminating in a moderately lobed appressorium were produced terminally. The cylindrical foot cells of the erect condiophores were 19.2 to 27.8 × 6.5 to 8.6 μm (average 23.3 × 7.7 μm). Fibrosin bodies were absent. Chasmothecia were observed mostly on the lower surfaces of leaves. At maturity, they were dark amber and spherical with a diameter of 92.9 to 151.0 μm (average 121.4 μm). Each chasmothecium contained six stalked asci (average size 63.7 × 35.9 μm). Each ascus contained four ellipsoid ascospores that measured 17.3 to 26.4 × 10.9 to 15.6 μm (average 23.3 × 12.8 μm). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced (1). The 602-bp sequence was deposited in GenBank under the Accession No. GQ149478 and was 99% similar to that of Erysiphe cruciferarum (Accession No. EU140958). As proof of pathogenicity, diseased leaves of C. hassleriana were pressed against leaves of three healthy 4-month-old potted plants of the same species for 10 min. Three noninoculated plants served as controls. Inoculated and noninoculated plants were maintained in a greenhouse at 22 to 25°C in isolation. After 11 days, typical powdery mildew colonies developed on inoculated plants. Noninoculated plants did not develop symptoms. The pathogenicity test was repeated once. Powdery mildew on C. hassleriana caused by E. cruciferarum was reported in Italy (2) but the pathogen was not characterized. Herbarium specimens are deposited at AGROINNOVA Collection, University of Torino, Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995.

scholarly journals Persimmon anthracnose: a comparative study of aggressiveness on shoot and fruit among Colletotrichum horii isolates in southern Brazil

2020 ◽  
Vol 50 (10) ◽  
Author(s):  
Renato Rezende Young Blood ◽  
Thiago de Aguiar Carraro ◽  
Josiane Gomes Figueiredo ◽  
Louise Larissa May De Mio
Keyword(s):  
Severe Disease ◽  
Its Region ◽  
Field Studies ◽  
Fungal Species ◽  
Metropolitan Region ◽  
Disease Symptoms ◽  
Immature Fruit ◽  
Anthracnose Disease ◽  
Persimmon Fruit ◽  
Fruit Drop

ABSTRACT: The persimmon tree is known for its rusticity and productivity and was first introduced to Brazil in the late 19th century. However, anthracnose disease is causing immature fruit drop and severe disease symptoms in persimmon fruit, shoots, flowers, and twigs. The causal agent was first described as the fungal species, Colletotrichum horii, which was first confirmed using only the ITS region. In this study, we compared the aggressiveness of 13 isolates of Colletotrichum spp. obtained from fruit and shoots of persimmon grown in the Metropolitan Region of Curitiba, Paraná State, Brazil. A multilocus molecular analysis was carried out based on ITS, GPDH, and EF genes, and we confirmed that the isolates were confirmed as C. horii. All isolates were pathogenic for unwounded and wounded persimmon fruit but differed in aggressiveness. Only one isolate was non-pathogenic when inoculated into unwounded persimmon shoots. Most isolates caused cankers and shoot death whether shoots were wounded or unwounded. In this study, we emphasized the importance of shoots as a source of primary inoculum. In future studies, it will be critical to further elucidate the epidemiological basis of anthracnose disease by conducting field studies to establish a more effective strategy for disease control.

scholarly journals Morphological and Molecular Identification of the Fungus Associated with Pink Disease of Cocoa (Theobroma cacao L) in the Eastern Region of Ghana

2018 ◽  
pp. 1-8
Author(s):  
F. G. Kwarteng ◽  
E. Cornelius ◽  
K. K. Acquah ◽  
E. K. Asare
Keyword(s):  
Theobroma Cacao ◽  
Fragment Size ◽  
Its Region ◽  
Eastern Region ◽  
Malt Extract ◽  
Causal Organism ◽  
Disease Symptoms ◽  
Similar Disease ◽  
Mean Similarity ◽  
Theobroma Cacao L

The Pink Disease is caused by the fungus Erythricium salmonicolor (Berk & Broome) Burdsall. It attacks broad hosts such as cocoa, coffee, citrus Eucalyptus spp. and Acasia spp. An outbreak of similar disease symptoms on cocoa trees in the Eastern region of Ghana has been a threat to the cocoa industry. However, the organism causing the disease in the Eastern region of Ghana has not been properly identified. Therefore, objectives of this study were to identify the causal organism of the pink disease of cocoa in the Eastern Region of Ghana and to also determine the genetic variability among the isolates collected. All isolates produced salmon-pink fluffy mycelia with concentric zones and regular margins on (Potatoes Dextrose Agar) PDA and Malt Extract Agar (MEA). The hyphae were hyaline, thin-walled, joined to each other and with clamp-connections.  Amplification of the ITS region of isolates of E. salmonicolor using primers produced a 750 bp which is the expected fragment size. The isolates varied genetically with mean similarity of 55%.  Isolates from Saamang, Bunso and Osino communities related by 78% whiles Isolates from Osino and Bunso communities clustered together at 88% making them the most related among all the isolates. 

scholarly journals Unusual Antigenic and Genetic Characteristics of Human Respiratory Syncytial Viruses Isolated in Cuba

1998 ◽  
Vol 72 (9) ◽  
pp. 7589-7592 ◽  
Author(s):  
Odalys Valdés ◽  
Isidoro Martínez ◽  
Angel Valdivia ◽  
Reynel Cancio ◽  
Clara Savón ◽  
...  
Keyword(s):  
G Protein ◽  
Protein Gene ◽  
Temperate Climate ◽  
Nucleotide Difference ◽  
Genetic Characteristics ◽  
Socioeconomic Characteristics ◽  
Genetic Level ◽  
Respiratory Syncytial Viruses ◽  
Syncytial Virus ◽  
Extra Nucleotide

ABSTRACT The G protein of 23 strains of human respiratory syncytial virus isolated in Havana, Cuba, between October 1994 and January 1995 was analyzed at the antigenic and genetic level. All viruses reacted with 10 of 11 antibodies specific for the Long strain. Moreover, the G protein gene of the Cuban isolates had only five nucleotide differences from the sequence of the Long gene. The homogeneity of the Cuban isolates and their resemblance to an ancient strain, such as Long, are at odds with previous findings for viruses isolated in countries with a temperate climate and different socioeconomic status. The G proteins of three of four other viruses isolated in Havana 2 years later (1996) were also identical to those of the 1994-to-1995 isolates, and the fourth virus had a single extra nucleotide difference. This, again, is unusual, since no identical viruses had been isolated in different epidemics previously. The singular characteristics of the Cuban isolates reported here are discussed in terms of the epidemiological, climatic, and socioeconomic characteristics of Cuba.

scholarly journals Habituation to thaxtomin A increases resistance to common scab in ‘Russet Burbank’ potato

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253414
Author(s):  
Nathalie Beaudoin ◽  
Iauhenia Isayenka ◽  
Audrey Ducharme ◽  
Sophie Massie ◽  
André Gagnon ◽  
...  
Keyword(s):  
Common Scab ◽  
Durable Resistance ◽  
Russet Burbank ◽  
Potato Tubers ◽  
Infected Tuber ◽  
Disease Symptoms ◽  
Thaxtomin A ◽  
Enhanced Resistance ◽  
Streptomyces Scabiei ◽  
Average Size

Common scab is a potato disease characterized by the formation of scab-like lesions on the surface of potato tubers. The actinobacterium Streptomyces scabiei is the main causal agent of common scab. During infection, this bacterium synthesizes the phytotoxin thaxtomin A which is essential for the production of disease symptoms. While thaxtomin A can activate an atypical programmed cell death in plant cell suspensions, it is possible to gradually habituate plant cells to thaxtomin A to provide resistance to lethal phytotoxin concentrations. Potato ‘Russet Burbank’ calli were habituated to thaxtomin A to regenerate the somaclone RB9 that produced tubers more resistant to common scab than those obtained from the original cultivar. Compared to the Russet Burbank cultivar, somaclone RB9 generated up to 22% more marketable tubers with an infected tuber area below the 5% threshold. Enhanced resistance was maintained over at least two years of cultivation in the field. However, average size of tubers was significantly reduced in somaclone RB9 compared to the parent cultivar. Small RB9 tubers had a thicker phellem than Russet Burbank tubers, which may contribute to improving resistance to common scab. These results show that thaxtomin A-habituation in potato is efficient to produce somaclones with increased and durable resistance to common scab.

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