Sample records for alternaria stem canker

  1. First record of Colletogloeopsis zuluense comb. nov., causing a stem canker of Eucalyptus in China

    E-print Network

    First record of Colletogloeopsis zuluense comb. nov., causing a stem canker of Eucalyptus in China. WINGFIELDa , Michael J. WINGFIELDa a Department of Genetics, Forestry and Agricultural Biotechnology Province, P.R. China d Centraalbureau voor Schimmelcultures, Uppsalalaan 8, 3584 CT Utrecht

  2. Detoxification of ?-tomatine by tomato pathogens Alternaria alternata tomato pathotype and Corynespora cassiicola and its role in infection

    Microsoft Academic Search

    Kumiko Oka; Akiko Okubo; Motoichiro Kodama; Hiroshi Otani

    2006-01-01

    In tomato plants, ?-tomatine, a steroidal glycoalkaloid saponin, inhibits fungal growth. Tomato pathogens that produce host-specific\\u000a toxins, Alternaria alternata tomato pathotype causing Alternaria stem canker and Corynespora cassiicola causing Corynespora target spot, were investigated for sensitivity to ?-tomatine. Although spore germination of A. alternata pathogenic and nonpathogenic to tomato and of C. cassiicola pathogenic to tomato was not affected by

  3. Assessing Quantitative Resistance against Leptosphaeria maculans (Phoma Stem Canker) in Brassica napus (Oilseed Rape) in Young Plants

    PubMed Central

    Huang, Yong-Ju; Qi, Aiming; King, Graham J.; Fitt, Bruce D. L.

    2014-01-01

    Quantitative resistance against Leptosphaeria maculans in Brassica napus is difficult to assess in young plants due to the long period of symptomless growth of the pathogen from the appearance of leaf lesions to the appearance of canker symptoms on the stem. By using doubled haploid (DH) lines A30 (susceptible) and C119 (with quantitative resistance), quantitative resistance against L. maculans was assessed in young plants in controlled environments at two stages: stage 1, growth of the pathogen along leaf veins/petioles towards the stem by leaf lamina inoculation; stage 2, growth in stem tissues to produce stem canker symptoms by leaf petiole inoculation. Two types of inoculum (ascospores; conidia) and three assessment methods (extent of visible necrosis; symptomless pathogen growth visualised using the GFP reporter gene; amount of pathogen DNA quantified by PCR) were used. In stage 1 assessments, significant differences were observed between lines A30 and C119 in area of leaf lesions, distance grown along veins/petioles assessed by visible necrosis or by viewing GFP and amount of L. maculans DNA in leaf petioles. In stage 2 assessments, significant differences were observed between lines A30 and C119 in severity of stem canker and amount of L. maculans DNA in stem tissues. GFP-labelled L. maculans spread more quickly from the stem cortex to the stem pith in A30 than in C119. Stem canker symptoms were produced more rapidly by using ascospore inoculum than by using conidial inoculum. These results suggest that quantitative resistance against L. maculans in B. napus can be assessed in young plants in controlled conditions. Development of methods to phenotype quantitative resistance against plant pathogens in young plants in controlled environments will help identification of stable quantitative resistance for control of crop diseases. PMID:24454767

  4. Comparison of terpenes in extracts from the resin and the bark of the resinous stem canker of Chamaecyparis obtusa and Thujopsis dolabrata var. hondae

    Microsoft Academic Search

    Nobuyasu Hanari; Hiroshi Yamamoto; Ken-ichi Kuroda

    2002-01-01

    A monoterpene and 15 diterpenes were isolated from the ethyl acetate extracts of the bark-glued resin from the resinous stem\\u000a canker ofThujopsis dolabrata var.hondae Makino. A monoterpene (nezukone20) and 4 diterpenes (acetyl torulosol5, acetyl isocupressic acid8, acetyl abietinol11, and 7?-methoxytotarol18) were characteristic constituents of the ethyl acetate extracts but were absent in then-hexane extracts from the resinous stem canker ofT.

  5. Canker sore

    MedlinePLUS

    ... and minerals in the diet (especially iron, folic acid , or vitamin B-12 ) Hormonal changes Food allergies Anyone can develop a canker sore. Women are more likely to get them than men. Canker sores may run in families.

  6. Canker Sores

    MedlinePLUS

    ... Fall Meeting Canker Sores Canker sores (recurrent aphthous stomatitis, RAS) are among the most common of oral ... appear. There are three main forms: Minor Aphthous Stomatitis: this is the form that affects more than ...

  7. Ability of a Leptosphaeria maculans isolate to form stem cankers on Indian mustard ( Brassica juncea ) segregates as a single locus

    Microsoft Academic Search

    Chang-Yong Chen; Kim M. Plummer; Barbara J. Howlett

    1996-01-01

    Australian isolates of the blackleg fungusLeptosphaeria maculans, that form cankers on two Indian mustard (Brassica juncea) varieties (Stoke and Zaria) are described. This ability to form cankers on var. Stoke segregates as a single locus in both F1 and backcross progeny from a cross between twoL. maculans isolates.

  8. Alternaria blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria blight of chickpea is caused by the fungal pathogen Alternaria alternata. The pathogen has wide host range, and affects all above ground parts of the plant. The disease occurs sporadically and occasionally could be economically important and causes significant damage. The pathogen can ...

  9. Myrothecium roridum leaf spot and stem canker on watermelon in the southern Great Plains: Possible factors for its outbreak

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diseases are generally the greatest yield-limiting factor for watermelon across the U.S. In 2010, a foliar and stem-lesion disease was observed for the first time in Oklahoma causing moderate to severe defoliation. Using microscopic examination, the physical features of the fungus were consistent ...

  10. Morphological and Molecular Characteristics of the Oak Tree Canker Pathogen, Annulohypoxylon truncatum

    PubMed Central

    Cha, Jaeyul; Heo, Bitna; Ahn, Soo Jeong; Gang, Guenhye; Park, Chung Gyoo

    2012-01-01

    Cankers are localized dead areas in the bark of stems, branches or twigs of many types of trees and shrubs, and are usually caused by fungi. We observed severe canker symptoms in oak trees located in Gyeongnam province in 2011. A total 31 trees were discovered with cankers of varied size, with an average of 48.5 × 15.2 cm. Black, half-rounded globular mound shaped stromata were associated with the cankers, and the asci of the fungi associated with the cankers were cylindrical shaped with their spore-bearing parts being up to 84 µm in length. The average fungal ascospores size was 7.59 × 4.23 µm. The internal transcribed spacer sequence for the canker causing fungus showed 99% similarity to the sequence of Annulohypoxylon truncatum. In this study, the isolated fungus was precisely described and then compared with fungi of similar taxa. PMID:22783140

  11. [Loquat canker: a new disease for Argentina].

    PubMed

    Alippi, A M; Alippi, H E

    1990-01-01

    A stem canker disease caused by Pseudomonas syringae pv. eriobotryae (Takimoto) Young, Dye y Wilkie on loquat (Eriobotrya Japonica [Thumb] Lindl) was recorded for the first time in Argentina. Symptoms of the disease appeared as dry stem cankers which in advanced stages surrounded the stems. Similar cankers were noticeable on leaves midribs. Seven bacterial strains were isolated from diseased loquats and their identification was based on disease symptoms, pathogenicity and cultural and biochemical characteristics. All strains were levan positive and gave a hypersensitive reaction on tobacco leaves. Neither arginine dehydrolase nor oxidase was detected in any of the strains which produced a diffusible green pigment on King B which fluoresced under UV light and a distinct diffusible brown pigment on King B, SPA and Tween 80 media within 5-7 days of incubation. Lipolysis of Tween 80 was also recorded. The symptoms observed in the field and obtained by experimental inoculations were similar to those induced by Pseudomonas syringae pv. eriobotryae in the original description of the disease. PMID:2102015

  12. Mutations at the Asc locus of tomato confer resistance to the fungal pathogen Alternaria alternata f. sp. lycopersici.

    PubMed

    van der Biezen, E A; Nijkamp, H J; Hille, J

    1996-05-01

    The fungal pathogen Alternaria alternata f. sp. lycopersici produces host-selective AAL-toxins that cause Alternaria stem canker in tomato. Susceptibility to the disease is based on the relative sensitivity of the host to the AAL-toxins and is controlled by the Asc locus on chromosome 3L. Chemical mutagenesis was employed to study the genetic basis of sensitivity to AAL-toxins and susceptibility to fungal infection. Following the treatment of seeds of a susceptible line with ethyl methanesulphonate (EMS), resistant M2 mutants were obtained. Most plants with induced resistances showed toxin-sensitivity responses that were comparable to those of resistant control lines carrying the Asc locus. In addition, genetic analysis of the mutagenised plants indicated that the mutations occurred at the Asc locus. Furthermore, novel mutants were identified that were insensitive to the AAL-toxins at the seedling stage but toxin-sensitive and susceptible to fungal infection at mature stages. No AAL-toxin-insensitive insertion mutants were identified following a transposon mutagenesis procedure. Molecular mechanisms involved in host defence against A a. lycopersici are discussed. PMID:24166557

  13. Effect of spores of saprophytic fungi on phytoalexin accumulation in seeds of frog-eye leaf spot and stem canker-resistant and -susceptible soybean (Glycine max L.) cultivars.

    PubMed

    Garcez, W S; Martins, D; Garcez, F R; Marques, M R; Pereira, A A; Oliveira, L A; Rondon, J N; Peruca, A D

    2000-08-01

    Two saprophytic fungi (Mucor ramosissimus and Rhizopus sp.) were tested for their ability to induce phytoalexin production by seeds of frog-eye leaf spot and stem canker-resistant and -susceptible soybean (Glycine max L.) cultivars. Only M. ramosissimus was shown to elicit a response and qualitative differences in phytoalexin accumulation were found between the susceptible and resistant cultivars. Glyceollins I, II, and III and glycinol were isolated from the susceptible cultivar, whereas Glyceollins I, II, and III, glycinol, glyceocarpin, genistein, isoformononetin, and N-acetyltyramine accumulated in the resistant cultivar in response to the same fungal elicitor. Genistein was found to be an inducibly formed isoflavonoid instead of a constitutive metabolite in the resistant cultivar, whereas N-acetyltyramine is described for the first time as a soybean phytoalexin. All the compounds, except genistein, showed fungitoxic activity against Cladosporium sphaerospermum. Spectral data of the pterocarpan phytoalexins, genistein, and N-acetyltyramine are also given in this work. PMID:10956166

  14. Walnut Twig Beetle and Thousand Cankers Disease: Field Identification Guide

    E-print Network

    Ishida, Yuko

    fungal cankers form, coalesce, and girdle branches and stems (E). (A) (B) (C) (D) (E) #12;Successful WTB, University of California, Davis, CA Tom W. Coleman, USDA Forest Service, Forest Health Protection, San. Seybold, USDA Forest Service, Pacific Southwest Research Station, Davis, CA Please cite this document as

  15. Effect of drought and defoliation on the susceptibility of eucalypts to cankers caused by Endothia gyrosa and Botryosphaeria ribis

    SciTech Connect

    Old, K.M.; Gibbs, R.; Craig, I.; Myers, B.J. (CSIRO, Canberra (Australia)); Yuan, Z.Q. (Xinjiang August 1st Agricultural College (China))

    1990-01-01

    Seedlings, saplings and mature eucalypts were susceptible to infection by Endothia gyrosa and Botryosphaeria ribis. Eucalyptus regnans and E. delegatensis were more susceptible than E. grandis and E. saligna. In trees not subjected to stress, cankers were limited in extent and often healed. When trees were defoliated, either manually or by severe insect attack, stem concentrations of both starch and soluble carbohydrates were reduced and canker development in some pathogen/host combinations was increased. Seedlings subjected to water stress were not predisposed to canker formation. The association of E. gyrosa with branch dieback of rural eucalypts suffering from chronic defoliation suggests that canker fungi contribute to the crown dieback syndrome in south-eastern Australia.

  16. CITRUS CANKER: PLANT PATHOLOGY VERSUS PUBLIC POLICY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing international travel and trade has resulted in an unprecedented number of plant pathogen introductions, including Xanthomonas axonopodis pv citri, (Xac), the bacterium that causes citrus canker. The disease affects commercial and dooryard citrus, and has far-reaching politi...

  17. Citrus Diseases Exotic to Florida: Citrus Tristeza Virus Stem Pitting (CTV-SP)1

    Microsoft Academic Search

    K.-R. Chung; R. H. Brlansky

    Citrus is susceptible to a large number of diseases caused by plant pathogens. Economic losses due to plant diseases can be severe, but fortunately, not all pathogens attacking citrus are present in Florida. Major citrus diseases currently present in Florida include: Alternaria brown spot, blight, citrus canker, greasy spot, melanose, Phytophthora-induced diseases (foot and root rot, brown rot), postbloom fruit

  18. A new compound from an endophytic fungus Alternaria tenuissima.

    PubMed

    Wu, Wen-Bin; Yue, Gao-Chao; Huang, Qi-Lin; Sun, Ling-Ling; Zhang, Wen

    2014-01-01

    A new secondary metabolite, named altertoxin IV (1), together with altertoxin II (2), was isolated from the fermentation broth of Alternaria tenuissima, an endophytic fungal strain residing in the stem of Tribulus terrestris L. The structure of new compound 1 was established by HR-ESI-MS, multinuclear NMR spectroscopy, and single crystal X-ray diffraction method. In their in vitro bioassay, compound 2 exhibited moderate cytotoxic activity against PC-3 cell lines with an IC50 value of 14.28 ?M. PMID:24660902

  19. Research progress for integrated canker management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit losses due to citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), vary each crop season depending on citrus variety, tree age, flushing condition, leafminer control, and coincidence of weather events with occurrence of susceptible fruit and foliage. In 2013, crop losses in Hamlin f...

  20. Regulation of mycotoxin biosynthesis inAlternaria.

    PubMed

    Häggblom, P; Hiltunen, M

    1991-03-01

    The genusAlternaria is responsible for different plant diseases such as tobacco brown spot, tomato blight, and citrus seedling chlorosis but can also be present during storage of grain. The objective of the present paper is to summarize the knowledge concerning regulation of secondary metabolism inAlternaria, particularA alternata (A tenuis). The paper mainly deals with regulation of polyketide biosynthesis, one of the major pathways leading to the biosynthesis of mycotoxins inAlternaria.The mostly studiedAlternaria mycotoxins are dibenzopyrones such as alternariol (AOH) and alternariol monomethyl ether (AME) and altenuene along with the tetramic acid tenuazonic acid.The biosynthesis ofAlternaria mycotoxins has been reviewed by Stinson (12). Most information is available for the biosynthesis of the polyketides AOH / AME while a few biosynthetic studies have been accomplished for tenuazonic acid (11). PMID:23605548

  1. Regulation of mycotoxin biosynthesis in Alternaria

    Microsoft Academic Search

    P Häggblom; M Hiltunen

    1991-01-01

    The genusAlternaria is responsible for different plant diseases such as tobacco brown spot, tomato blight, and citrus seedling chlorosis but\\u000a can also be present during storage of grain. The objective of the present paper is to summarize the knowledge concerning regulation\\u000a of secondary metabolism inAlternaria, particularA alternata (A tenuis). The paper mainly deals with regulation of polyketide biosynthesis, one of

  2. Managing citrus canker for the fresh fruit industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The establishment of citrus canker in Florida changed the way the $400 million dollar industry grows, packs ships and stores fruit. Canker regulations have become less strict, but there is still a requirement for compliance for growers and packers to move fruit from Florida to other areas. The comp...

  3. Cryphonectria canker on Tibouchina in Colombia By M. J. WINGFIELD

    E-print Network

    Cryphonectria canker on Tibouchina in Colombia By M. J. WINGFIELD 1 , C. RODAS 2 , H. MYBURG 3 , M.Wing®eld@fabi.up.ac.za; 2 Smur®t Carton de Colombia, Cali, Colombia and Wright Forest Management Consultants Inc., Cary NC canker disease on Tibouchina spp. (Melastomataceae) in Colombia. We used morphological studies

  4. Susceptibility of citrus species to Alternaria alternata, the causal agent of the Alternaria brown spot

    Microsoft Academic Search

    R. F. Reis; T. F. de Almeida; E. S. Stuchi; A. de Goes

    2007-01-01

    Alternaria alternata, the causal agent of Alternaria brown spot (ABS), causes necrosis on leaves, twigs, and fruit, reducing the productivity and quality of fruits. Tangerines and their hybrids are highly susceptible to the disease. Species, hybrids, and cultivars of Citrus from the germplasm bank of the Estação Experimental de Citricultura de Bebedouro, São Paulo, Brazil, were evaluated in 2004 and

  5. Citrus Canker: The Pathogen and Its Impact

    NSDL National Science Digital Library

    2002-01-01

    This Web site, currently featured on the home page of the American Phytopathological Society, contains a research report regarding the Asiatic citrus canker that has had devastating effects on Florida's citrus industry. The report, in a journal article format, thoroughly relates the natural history and current status of the disease, as well as detailing the methods and results of the (primarily genetic) experiments conducted in this study. One of the most appealing features of this Web site is the quality of the photos within the report. These photos can be viewed separately from the report in a slide show. While navigating this site is relatively straightforward, the lack of a table of contents can make finding your place in the body of the text somewhat confusing.

  6. Molecular, ecological and evolutionary approaches to understanding Alternaria diseases of citrus

    Microsoft Academic Search

    Kazuya Akimitsu; Tobin L. Peever; L. W. Timmer

    2003-01-01

    SUMMARY Alternaria fungi cause four different diseases of citrus: Alternaria brown spot of tangerines, Alternaria leaf spot of rough lemon, Alternaria black rot of several citrus fruits and Mancha foliar of Mexican lime. The first three diseases are caused by the small- spored species, Alternaria alternata and the causal agents can only be differentiated using pathogenicity tests, toxin assays or

  7. 40 CFR 180.1256 - Alternaria destruens strain 059; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Alternaria destruens strain 059; exemption from...Exemptions From Tolerances § 180.1256 Alternaria destruens strain 059; exemption...for residues of the microbial pesticide Alternaria destruens Strain 059 when used...

  8. 40 CFR 180.1256 - Alternaria destruens strain 059; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Alternaria destruens strain 059; exemption from...Exemptions From Tolerances § 180.1256 Alternaria destruens strain 059; exemption...for residues of the microbial pesticide Alternaria destruens Strain 059 when used...

  9. New antitumour fungal metabolites from Alternaria porri.

    PubMed

    Phuwapraisirisan, Preecha; Rangsan, Jakaphan; Siripong, Pongpan; Tip-Pyang, Santi

    2009-01-01

    Chemical investigation of the onion pathogenic fungus Alternaria porri resulted in the isolation of two new phthalides named zinnimide (2) and deprenylzinnimide (8), along with a new bianthraquinone, alterporriol F (10). The structures of the new metabolites were characterised by spectroscopic analysis and chemical degradation. Of the new compounds isolated, alterporriol F was highly cytotoxic towards HeLa and KB cells, with IC(50) values of 6.5 and 7.0 microg mL(-1). PMID:19662571

  10. Alternaria in Food: Ecophysiology, Mycotoxin Production and Toxicology.

    PubMed

    Lee, Hyang Burm; Patriarca, Andrea; Magan, Naresh

    2015-06-01

    Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity (aw), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance (ID) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed. PMID:26190916

  11. Alternaria in Food: Ecophysiology, Mycotoxin Production and Toxicology

    PubMed Central

    Patriarca, Andrea; Magan, Naresh

    2015-01-01

    Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity (aw), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance (ID) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed. PMID:26190916

  12. Evaluation of tangerine hybrid resistance to Alternaria alternata

    Microsoft Academic Search

    Marcelo Claro de Souza; Eduardo Sanches Stuchi; Antonio de Goes

    2009-01-01

    The Alternaria Brown Spot, caused by Alternaria alternata, is a major fungal disease in some kinds of tangerines, tangor, mandarins and pomelos. In Brazil as well as worldwide, A. alternata can cause necrosis in fruits, branches and leaves, causing substantial profit loss. In the present research, in laboratory conditions and in the field, we evaluated the resistance to the fungus,

  13. Control of Alternaria brown spot of Minneola tangelo with fungicides

    Microsoft Academic Search

    Z. Solel; Y. Oren; Miriam Kimchi

    1997-01-01

    Field experiments to control fruit lesions of Alternaria brown spot (Alternaria alternata pathovar citri) of Minneola tangelo (Citrus reticulata × C. paradisi) were conducted over a period of 5 years. Iprodione at 0.5 g a.i. l ? 1 was consistently effective in reducing fruit lesions when sprayed four or five times at 2 week intervals, beginning shortly after full bloom

  14. First Record of Alternaria simsimi Causing Leaf Spot on Sesame (Sesamum indicum L.) in Korea

    PubMed Central

    Choi, Young Phil; Paul, Narayan Chandra

    2014-01-01

    Leaf spot disease was observed in sesame (Sesamum indicum L.) during 2009 and 2010 in Korea. The pathogen was identified as Alternaria simsimi based on morphological and cultural characteristics. The morphological identification was well supported by phylogenetic analysis of the ribosomal DNA-internal transcribed spacer region. A. simsimi isolates caused spot symptoms on leaves and stems of sesame plants 2 wk after artificial inoculation, which were similar to those observed in the field. This is the first record of leaf spot disease in Korea caused by A. simsimi. PMID:25606015

  15. First Record of Alternaria simsimi Causing Leaf Spot on Sesame (Sesamum indicum L.) in Korea.

    PubMed

    Choi, Young Phil; Paul, Narayan Chandra; Lee, Hyang Burm; Yu, Seung Hun

    2014-12-01

    Leaf spot disease was observed in sesame (Sesamum indicum L.) during 2009 and 2010 in Korea. The pathogen was identified as Alternaria simsimi based on morphological and cultural characteristics. The morphological identification was well supported by phylogenetic analysis of the ribosomal DNA-internal transcribed spacer region. A. simsimi isolates caused spot symptoms on leaves and stems of sesame plants 2 wk after artificial inoculation, which were similar to those observed in the field. This is the first record of leaf spot disease in Korea caused by A. simsimi. PMID:25606015

  16. Stems

    NSDL National Science Digital Library

    Olivia Worland (Purdue University; Biological Sciences)

    2008-06-03

    Some mature plants can produce new plants by cutting a piece of stem off of the original plant. Most members of the mint family and ivy family can do this readily. The new plant will grow its own root system.

  17. Toxicity of Solanum xanthocarpum fruit extract against Alternaria brassicae, causal agent of Alternaria blight of Indian mustard (Brassica juncea)

    Microsoft Academic Search

    Sanjay Guleria; Ashok Kumar; A. K. Tiku

    2010-01-01

    Fruit extract of Solanum xanthocarpum was evaluated for its toxicity against Alternaria brassicae, the causal agent of Alternaria blight of Indian mustard [Brassica juncea (L.) Czern. & Coss]. The mass obtained after vacuum drying of the crude methanolic extract was utilised for further sequential fractionation using n-hexane, ethyl acetate, n-butanol and methanol. Among the crude and different fractions tested, methanolic

  18. PROSPECTS FOR CONTROL OF CITRUS CANKER WITH NOVEL CHEMICAL COMPOUNDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field trials conducted in Brazil demonstrate that copper formulations (copper hydroxide, CH; copper oxychloride, COC) even at reduced rates are consistently effective for control of canker on moderately susceptible orange varieties. Contact activity to replace and/or reduce copper could minimize po...

  19. Pruning for prevention and management of canker diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trunk diseases (wood-canker diseases) threaten all California vineyards due to widespread distribution of the fungal pathogens. The infections are chronic and occur each year. Trunk diseases in mature vineyards reduce yields and increase management costs to the point where the vineyard is no longer ...

  20. The Eucalyptus canker pathogen Chrysoporthe cubensis discovered in eastern Australia

    E-print Network

    The Eucalyptus canker pathogen Chrysoporthe cubensis discovered in eastern Australia Geoffrey S Pathology Centre, The University of Queensland/Agri-Science Queensland, Qld 4068, Australia. B Forestry these trees are planted as non-natives. Although the majority of Eucalyptus spp. are native to Australia, Chr

  1. Automating the assessment of citrus canker symptoms with image analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (CC, caused by Xanthomonas citri) is a serious disease of citrus in Florida and other citrus-growing regions. Severity of symptoms can be estimated by visual rating, but there is inter- and intra-rater variation. Automated image analysis (IA) may offer a way of reducing some of ...

  2. Distribution of canker lesions on grapefruit in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by the plant pathogenic bacterium Xanthomonas citri subsp. citri (Xcc) is an important disease of grapefruit in Florida. To establish disease distribution on fruit, six samples of 24 diseased grapefruit were collected from two groves in east Florida. A plane was sliced through ...

  3. Developing Transgenic Citrus for Resistance to Huanglongbing and Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Bacterial Canker (CBC) are serious threats to citrus production, and resistant transgenic citrus is desirable. Genes for antimicrobial peptides (AMPs) with diverse promoters have been used to generate thousands of rootstock and scion transformants. D35S::D4E1 transfor...

  4. Botryosphaeriaceae associated with Eucalyptus canker diseases in Colombia

    E-print Network

    Botryosphaeriaceae associated with Eucalyptus canker diseases in Colombia By C. A. Rodas1,3 , B, Pretoria, 0002, South Africa; 3 Smurfit Carto´n de Colombia, Investigacio´n Forestal, Carrera 3 No. 10-36, Cali, Valle, Colombia. 4 E-mail: bernard.slippers@fabi.up.ac.za (for correspondence) Summary

  5. Citrus diseases with global ramifications including citrus canker and huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although there are a number of diseases that plague citrus production worldwide, two bacterial diseases are particularly problematic. Both are of Asian origin and currently cause severe economic damage: Asiatic citrus canker (ACC) and citrus huanglongbing (HLB). Although ACC has been found in the ...

  6. Large-spored Alternaria pathogens in section Porri disentangled.

    PubMed

    Woudenberg, J H C; Truter, M; Groenewald, J Z; Crous, P W

    2014-09-01

    The omnipresent fungal genus Alternaria was recently divided into 24 sections based on molecular and morphological data. Alternaria sect. Porri is the largest section, containing almost all Alternaria species with medium to large conidia and long beaks, some of which are important plant pathogens (e.g. Alternaria porri, A. solani and A. tomatophila). We constructed a multi-gene phylogeny on parts of the ITS, GAPDH, RPB2, TEF1 and Alt a 1 gene regions, which, supplemented with morphological and cultural studies, forms the basis for species recognition in sect. Porri. Our data reveal 63 species, of which 10 are newly described in sect. Porri, and 27 species names are synonymised. The three known Alternaria pathogens causing early blight on tomato all cluster in one clade, and are synonymised under the older name, A. linariae. Alternaria protenta, a species formerly only known as pathogen on Helianthus annuus, is also reported to cause early blight of potato, together with A. solani and A. grandis. Two clades with isolates causing purple blotch of onion are confirmed as A. allii and A. porri, but the two species cannot adequately be distinguished based on the number of beaks and branches as suggested previously. This is also found among the pathogens of Passifloraceae, which are reduced from four to three species. In addition to the known pathogen of sweet potato, A. bataticola, three more species are delineated of which two are newly described. A new Alternaria section is also described, comprising two large-spored Alternaria species with concatenate conidia. PMID:25492985

  7. The distribution and spread of citrus canker in Emerald, Australia

    Microsoft Academic Search

    C. F. Gambley; A. K. Miles; M. Ramsden; V. Doogan; J. E. Thomas; K. Parmenter; P. J. L. Whittle

    2009-01-01

    Citrus canker is a disease of citrus and closely related species, caused by the bacterium Xanthomonas citri subsp. citri. This disease, previously exotic to Australia, was detected on a single farm [infested premise-1, (IP1). IP is the terminology\\u000a used in official biosecurity protocols to describe a locality at which an exotic plant pest has been confirmed or is presumed\\u000a to

  8. BARK CANKER OF UNKNOWN ETIOLOGY DEVELOPING ON PECAN CARYA ILLINOENSIS TREES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pecan trees in a five-year-old orchard of 17 cultivars had symptoms of an unusual bark canker first noticed in October, 2002. Symptoms appeared from ground line up to 3 meters on the central leader and most likely were initiated during the summer of 2002. Cankers developed around buds of the trunk...

  9. Automated image analysis of the severity of foliar citrus canker symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri) is a destructive disease, reducing yield, and rendering fruit unfit for fresh sale. Accurate assessment of citrus canker severity and other diseases is needed for several purposes, including monitoring epidemics and evaluation of germplasm. ...

  10. Comparison of Assessment of Citrus Canker Foliar Symptoms by Experienced and Inexperienced Raters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri) is destructive in many citrus production regions in tropical and subtropical parts of the world. Assessment of canker symptoms is required for diverse reasons, including monitoring epidemics, evaluating the efficacy of control strategies, and disease re...

  11. Detecting citrus canker by hyperspectral reflectance imaging and PCA-based image classification method

    NASA Astrophysics Data System (ADS)

    Qin, Jianwei; Burks, Thomas F.; Kim, Moon S.; Chao, Kuanglin; Ritenour, Mark A.

    2008-04-01

    Citrus canker is one of the most devastating diseases that threaten citrus crops. Technologies that can efficiently identify citrus canker would assure fruit quality and safety and enhance the competitiveness and profitability of the citrus industry. This research was aimed to investigate the potential of using hyperspectral imaging technique for detecting canker lesions on citrus fruit. A portable hyperspectral imaging system consisting of an automatic sample handling unit, a light source, and a hyperspectral imaging unit was developed for citrus canker detection. The imaging system was used to acquire reflectance images from citrus samples in the wavelength range between 400 nm and 900 nm. Ruby Red grapefruits with normal and various diseased skin conditions including canker, copper burn, greasy spot, wind scar, cake melanose, and specular melanose were tested. Hyperspectral reflectance images were analyzed using principal component analysis (PCA) to compress the 3-D hyperspectral image data and extract useful image features that could be used to discriminate cankerous samples from normal and other diseased samples. Image processing and classification algorithms were developed based upon the transformed images of PCA. The overall accuracy for canker detection was 92.7%. This research demonstrated that hyperspectral imaging technique could be used for discriminating citrus canker from other confounding diseases.

  12. ENHANCED DETECTION AND ISOLATION OF THE WALNUT PATHOGEN BRENNARIA RUBRIFACIENS: CAUSAL AGENT OF DEEP BARK CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deep bark canker (DBC) of walnut is caused by the bacterium Brenneria rubrifaciens which produces the red pigment rubrifacine. This disease of English walnut trees, is characterized by deep vertical cankers which exude sap laden with B. rubrifaciens. Although DBC is not observed on younger trees, ...

  13. Enhanced detection and isolation of the walnut pathogen Brenneria rubrifaciens , causal agent of deep bark canker

    Microsoft Academic Search

    Ali E. McClean; Padma Sudarshana; Daniel A. Kluepfel

    2008-01-01

    Deep bark canker (DBC) of walnut is caused by the bacterium Brenneria rubrifaciens which produces the red pigment rubrifacine. This disease of English walnut trees, is characterized by deep vertical cankers\\u000a which exude sap laden with B. rubrifaciens. Although DBC is not observed on young trees, it is hypothesized that B. rubrifaciens is present in host tissue years before symptom

  14. First report of citrus canker caused by Xanthomonas citri in Somalia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri, causal agent of citrus canker, has been reported in several countries in Africa, but not Somalia. During 2006 and 2007, hyperplasia-type lesions, often surrounded by a water-soaked margin and yellow halo, typical of citrus canker caused by X. citri, were found on 8-10 year-old gr...

  15. Characterization of Alternaria infectoria extracellular vesicles

    PubMed Central

    Silva, Branca M.A.; Prados-Rosales, Rafael; Espadas-Moreno, Javier; Wolf, Julie M.; Luque-Garcia, Jose L.; Gonçalves, Teresa; Casadevall, Arturo

    2015-01-01

    Many fungi use membrane vesicles to transport complex molecules across their cell walls. Like mammalian exosomes, fungal vesicles contain lipids, proteins, and polysaccharides, many of which are associated with virulence. Here we identify and characterize extracellular vesicles (EVs) in Alternaria infectoria, a ubiquitous, environmental filamentous fungus that is also an opportunistic human pathogen. Examination of the A. infectoria EVs revealed a morphology similar to that of vesicles described in other fungal species. Of note, proteomic analysis detected a reduced number of vesicle-associated proteins. There were two prevalent categories among the 20 identified proteins, including the polysaccharide metabolism group, probably related to plant host invasion or biosynthesis/degradation of cell wall components, and the nuclear proteins, especially DNA repair enzymes. We also found enzymes related to pigment synthesis, adhesion to the host cell, and trafficking of vesicles/organelles/molecules. This is the first time EV secretions have been identified in a filamentous fungus. We believe that these vesicles might have a role in virulence. PMID:24576997

  16. Associação de Alternaria dauci e A. alternata com sementes de coentro e eficiência do tratamento químico

    Microsoft Academic Search

    Ailton Reis; Jaqueson F Satelis; Roseane S Pereira; Warley Marcos Nascimento

    2006-01-01

    Association of Alternaria dauci and A. alternata with coriander seeds and efficiency of chemical treatments Twelve lots of coriander seeds were evaluated for the presence of Alternaria spp., using 600 seeds per lot in the blotter test. Two Alternaria species were detected, A. dauci (AD) in eight lots and A. alternata (AA) in six lots. A sample of 400 seeds

  17. Endopolygalacturonase is essential for citrus black rot caused by Alternaria citri but not brown spot caused by Alternaria alternata.

    PubMed

    Isshiki, A; Akimitsu, K; Yamamoto, M; Yamamoto, H

    2001-06-01

    Alternaria citri, the cause of Alternaria black rot, and Alternaria alternata rough lemon pathotype, the cause of Alternaria brown spot, are morphologically indistinguishable pathogens of citrus: one causes rot by macerating tissues and the other causes necrotic spots by producing a host-selective toxin. To evaluate the role of endopolygalacturonase (endoPG) in pathogenicity of these two Alternaria spp. pathogens, their genes for endoPG were mutated by gene targeting. The endoPGs produced by these fungi have similar biochemical properties, and the genes are highly similar (99.6% nucleotide identity). The phenotypes of the mutants, however, are completely different. An endoPG mutant of A. citri was significantly reduced in its ability to cause black rot symptoms on citrus as well as in the maceration of potato tissue and could not colonize citrus peel segments. In contrast, an endoPG mutant of A. alternata was unchanged in pathogenicity. The results indicate that a cell wall-degrading enzyme can play different roles in the pathogenicity of fungal pathogens. The role of a cell wall-degrading enzyme depends upon the type of disease but not the taxonomy of the fungus. PMID:11386370

  18. Toxigenic profile and AFLP variability of Alternaria alternata and Alternaria infectoria occurring on wheat

    PubMed Central

    Oviedo, María Silvina; Sturm, María Elena; Reynoso, María Marta; Chulze, Sofia Noemi; Ramirez, María Laura

    2013-01-01

    The objectives of this study were to evaluate the ability to produce alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by A. alternata and A. infectoria strains recovered from wheat kernels obtained from one of the main production area in Argentina; to confirm using AFLPs molecular markers the identify of the isolates up to species level, and to evaluate the intra and inter-specific genetic diversity of these two Alternaria species. Among all the Alternaria strains tested (254), 84% of them were able to produce mycotoxins. The most frequent profile of toxin production found was the co-production of AOH and AME in both species tested. TA was only produced by strains of A. alternata. Amplified fragment polymorphism (AFLPs) analysis was applied to a set of 89 isolates of Alternaria spp (40 were A. infectoria and 49 were A. alternata) in order to confirm the morphological identification. The results showed that AFLPs are powerful diagnostic tool for differentiating between A. alternata and A. infectoria. Indeed, in the current study the outgroup strains, A. tenuissima was consistently classified. Characteristic polymorphic bands separated these two species regardless of the primer combination used. Related to intraspecific variability, A. alternata and A. infectoria isolates evaluated seemed to form and homogeneous group with a high degree of similarity among the isolates within each species. However, there was more scoreable polymorphism within A. alternata than within A. infectoria isolates. There was a concordance between morphological identification and separation up to species level using molecular markers. Clear polymorphism both within and between species showed that AFLP can be used to asses genetic variation in A. alternata and A. infectoria. The most important finding of the present study was the report on AOH and AME production by A. infectoria strains isolated from wheat kernels in Argentina on a semisynthetic media for the first time. Also, specific bands for A. alternata and A. infectoria have been identified; these may be useful for the design of specific PCR primers in order to differentiate these species and to detect them in cereals. PMID:24294236

  19. Toxigenic profile and AFLP variability of Alternaria alternata and Alternaria infectoria occurring on wheat.

    PubMed

    Oviedo, María Silvina; Sturm, María Elena; Reynoso, María Marta; Chulze, Sofia Noemi; Ramirez, María Laura

    2013-01-01

    The objectives of this study were to evaluate the ability to produce alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by A. alternata and A. infectoria strains recovered from wheat kernels obtained from one of the main production area in Argentina; to confirm using AFLPs molecular markers the identify of the isolates up to species level, and to evaluate the intra and inter-specific genetic diversity of these two Alternaria species. Among all the Alternaria strains tested (254), 84% of them were able to produce mycotoxins. The most frequent profile of toxin production found was the co-production of AOH and AME in both species tested. TA was only produced by strains of A. alternata. Amplified fragment polymorphism (AFLPs) analysis was applied to a set of 89 isolates of Alternaria spp (40 were A. infectoria and 49 were A. alternata) in order to confirm the morphological identification. The results showed that AFLPs are powerful diagnostic tool for differentiating between A. alternata and A. infectoria. Indeed, in the current study the outgroup strains, A. tenuissima was consistently classified. Characteristic polymorphic bands separated these two species regardless of the primer combination used. Related to intraspecific variability, A. alternata and A. infectoria isolates evaluated seemed to form and homogeneous group with a high degree of similarity among the isolates within each species. However, there was more scoreable polymorphism within A. alternata than within A. infectoria isolates. There was a concordance between morphological identification and separation up to species level using molecular markers. Clear polymorphism both within and between species showed that AFLP can be used to asses genetic variation in A. alternata and A. infectoria. The most important finding of the present study was the report on AOH and AME production by A. infectoria strains isolated from wheat kernels in Argentina on a semisynthetic media for the first time. Also, specific bands for A. alternata and A. infectoria have been identified; these may be useful for the design of specific PCR primers in order to differentiate these species and to detect them in cereals. PMID:24294236

  20. A Novel Alternaria Species Isolated from Peucedanum japonicum in Korea.

    PubMed

    Deng, Jian Xin; Cho, Hye Sun; Paul, Narayan Chandra; Lee, Hyang Burm; Yu, Seung Hun

    2014-03-01

    We isolated and examined a new Alternaria sp., which causes leaf spots on Peucedanum japonicum in Korea, by using molecular and morphological methods. Phylogenetic analysis based on a combined internal transcribed spacer region analysis and two protein-coding genes (gpd and Alt a1) demonstrated that the causal fungus was most closely related to A. cinerariae and A. sonchi, and relevant to A. brassicae. However, conidial morphology indicated that it is a novel species within the genus Alternaria, and therefore we have assigned the fungus a new name in this study. PMID:24808728

  1. A Novel Alternaria Species Isolated from Peucedanum japonicum in Korea

    PubMed Central

    Deng, Jian Xin; Cho, Hye Sun; Paul, Narayan Chandra; Lee, Hyang Burm

    2014-01-01

    We isolated and examined a new Alternaria sp., which causes leaf spots on Peucedanum japonicum in Korea, by using molecular and morphological methods. Phylogenetic analysis based on a combined internal transcribed spacer region analysis and two protein-coding genes (gpd and Alt a1) demonstrated that the causal fungus was most closely related to A. cinerariae and A. sonchi, and relevant to A. brassicae. However, conidial morphology indicated that it is a novel species within the genus Alternaria, and therefore we have assigned the fungus a new name in this study. PMID:24808728

  2. Molecular systematics of citrus-associated Alternaria species.

    PubMed

    Peever, T L; Su, G; Carpenter-Boggs, L; Timmer, L W

    2004-01-01

    The causal agents of Alternaria brown spot of tangerines and tangerine hybrids, Alternaria leaf spot of rough lemon and Alternaria black rot of citrus historically have been referred to as Alternaria citri or A. alternata. Ten species of Alternaria recently were described among a set of isolates from leaf lesions on rough lemon (Citrus jambhiri) and tangelo (C. paradisi × C. reticulata), and none of these isolates was considered representative of A. alternata or A. citri. To test the hypothesis that these newly described morphological species are congruent with phylogenetic species, selected Alternaria brown spot and leaf spot isolates, citrus black rot isolates (post-harvest pathogens), isolates associated with healthy citrus tissue and reference species of Alternaria from noncitrus hosts were scored for sequence variation at five genomic regions and used to estimate phylogenies. These data included 432 bp from the 5' end of the mitochondrial ribosomal large subunit (mtLSU), 365 bp from the 5' end of the beta-tubulin gene, 464 bp of an endopolygalacturonase gene (endoPG) and 559 and 571 bp, respectively, of two anonymous genomic regions (OPA1-3 and OPA2-1). The mtLSU and beta-tubulin phylogenies clearly differentiated A. limicola, a large-spored species causing leaf spot of Mexican lime, from the small-spored isolates associated with citrus but were insufficiently variable to resolve evolutionary relationships among the small-spored isolates from citrus and other hosts. Sequence analysis of translation elongation factor alpha, calmodulin, actin, chitin synthase and 1, 3, 8-trihydroxynaphthalene reductase genes similarly failed to uncover significant variation among the small-spored isolates. Phylogenies estimated independently from endoPG, OPA1-3 and OPA2-1 data were congruent, and analysis of the combined data from these regions revealed nine clades, eight of which contained small-spored, citrus-associated isolates. Lineages inferred from analysis of the combined dataset were in general agreement with described morphospecies, however, three clades contained more than one morphological species and one morphospecies (A. citrimacularis) was polyphyletic. Citrus black rot isolates also were found to be members of more than a single lineage. The number of morphospecies associated with citrus exceeded that which could be supported under a phylogenetic species concept, and isolates in only five of nine phylogenetic lineages consistently were correlated with a specific host, disease or ecological niche on citrus. We advocate collapsing all small-spored, citrus-associated isolates of Alternaria into a single phylogenetic species, A. alternata. PMID:21148834

  3. Genetic variability in the pistachio late blight fungus, Alternaria alternata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic variation in the pistachio late blight fungus, Alternaria alternata, was investigated by restriction fragment length polymorphism (RFLP) in the rDNA region. Southern hybridization of EcoRI, HindIII, and Xbal digested fungal DNA with a RNA probe derived from Alt1, an rDNA clone isolated from ...

  4. Biodecolorization of acid violet 19 by Alternaria solani

    Microsoft Academic Search

    Hazrat Ali; Shah Khalid Muhammad

    Microorganisms are the nature's tools for cleaning the environment. Bioremediation using bacteria, fungi and algae is becoming an attractive option for the treatment of industrial effluents containing a wide spectrum of pollutants including dyes and heavy metal ions. In the current research work, the potential of a deuteromycete fungus, Alternaria solani for the removal of a dye, Acid Violet 19

  5. Alternaria alternata and its allergens: a comprehensive review.

    PubMed

    Kustrzeba-Wójcicka, Irena; Siwak, Emilia; Terlecki, Grzegorz; Wola?czyk-M?drala, Anna; M?drala, Wojciech

    2014-12-01

    Alternaria alternata is mainly an outdoor fungus whose spores disseminate in warm, dry air, so in temperate climates, their count peaks in the summers. Alternaria may also be found in damp, insufficiently ventilated houses, where its allergenic properties cocreate the sick building syndrome. Mold-induced respiratory allergies and research on Alternaria both have a lengthy history: the first was described as early as 1698 and the second dates back to 1817. However, the two were only linked in 1930 when Alternaria spores were found to cause allergic asthma. The allergenic extracts from Alternaria hyphae and spores still remain in use but are variable and insufficiently standardized as they are often a random mixture of allergenic ingredients and coincidental impurities. In contrast, contemporary biochemistry and molecular biology make it possible to obtain pure allergen molecules. To date, 16 allergens of A. alternata have been isolated, many of which are enzymes: Alt a 4 (disulfide isomerase), Alt a 6 (enolase), Alt a 8 (mannitol dehydrogenase), Alt a 10 (alcohol dehydrogenase), Alt a 13 (glutathione-S-transferase), and Alt a MnSOD (Mn superoxide dismutase). Others have structural and regulatory functions: Alt a 5 and Alt a 12 comprise the structure of large ribosomal subunits and mediate translation, Alt a 3 is a molecular chaperone, Alt a 7 regulates transcription, Alt a NTF2 facilitates protein import into the nucleus, and Alt a TCTP acts like a cytokine. The function of four allergenic proteins, Alt a 1, Alt a 2, Alt a 9, and Alt a 70 kDa, remains unknown. PMID:25205364

  6. [Colonization characteristics of endophytic bacteria NJ13 in Panax ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng].

    PubMed

    Chen, Chang-Qing; Li, Tong; Li, Xin-Lian; Jiang, Yun; Tian, Lei; Xu, Peng

    2014-05-01

    To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG. PMID:25282882

  7. Comparison of enzyme immunoassay–based assays for environmental Alternaria alternata

    PubMed Central

    Barnes, Charles; Portnoy, Jay; Sever, Michelle; Arbes, Samuel; Vaughn, Ben; Zeldin, Darryl C.

    2007-01-01

    Background Alternaria alternata–derived allergenic materials are causes of human disease. Several immunoassays exist to quantify these materials. Objective To compare methods for evaluating Alternaria content. Methods Four methods, including 1 monoclonal antibody (MAb)–based assay specific for recombinant Alt a 1, 1 MAb-based assay for chromatographically purified Alt a 1, 1 polyclonal antibody (PAb)–based assay for chromatographically purified Alt a 1, and 1 PAb-based assay for whole Alternaria extract, were evaluated. Environmental samples collected as part of the National Survey of Lead and Allergens in Housing were examined. Alternaria spore counts were determined in dust by observation. Results The MAb-based assay for recombinant Alt a 1 detected Alternaria in few samples (25%); the PAb-based assay for whole Alternaria proteins detected antigen in 97% of the samples. The PAb- and MAb-based assays for purified Alt a 1 detected antigen in 100% of the samples. There was a significant positive correlation between the 2 assays directed against purified Alt a 1. There was a positive correlation between the PAb-based assay for whole Alternaria and the PAb-based assay for Alt a 1. Nearly all the dust samples contained Alternaria spores, and there was a strong positive correlation between counts and all assays. Conclusion Because of the multifaceted nature of Alternaria, the disparities between methods for quantifying Alternaria, the cross-reactivity between fungal allergens, and the documented genetic promiscuity of this fungus, enzyme immunoassays using PAbs against a range of Alternaria proteins will probably produce the most reliable estimation of overall Alternaria exposure in house dust. PMID:17042141

  8. Thousand Canker Disease of Black Walnut Indiana Emergency Rule Indiana's Emergency Rule for Thousand Canker Disease of Black Walnut (TCD) will be effective

    E-print Network

    Thousand Canker Disease of Black Walnut ­ Indiana Emergency Rule Indiana's Emergency Rule, and recently added Tennessee may not come into Indiana without an inspection at the point of origin by a state before they are to come into Indiana. The primary concern is Tennessee as it is the most likely source

  9. A method for estimating white pine blister rust canker age on limber pine in the central Rocky Mountains

    Microsoft Academic Search

    Holly S. J. Kearns; William R. Jacobi; Brian W. Geils

    2009-01-01

    Summary Epidemiological studies of white pine blister rust on limber pine require a temporal component to explain variations in incidence of infection and mortality. Unfortunately, it is not known how long the pathogen has been present at various sites in the central Rocky Mountains of North America. Canker age, computed from canker length and average expansion rate, can be used

  10. A New Canker Disease of Apple, Pear, and Plum Rootstocks Caused by Diaporthe ambigua in South Africa

    E-print Network

    A New Canker Disease of Apple, Pear, and Plum Rootstocks Caused by Diaporthe ambigua in South., Wingfield. B. D.. Wingfield. M. 1., and Calitz. F. J. 1996. A new canker disease of apple. pear, and plum was found to be the c:J.useof a newly recognized disease of apple. pear, and plum rootstocks in South Africa

  11. Correlation of ethylene synthesis in Citrus fruits and their susceptibility to Alternaria alternata pv. citri

    Microsoft Academic Search

    A. Ortuño; I. Nemsa; N. Alvarez; A. Lacasa; I. Porras; A. Garcia Lidón; J. A. Del Río

    2008-01-01

    The susceptibility of Fortune (Citrus clementina×Citrus reticulata), Citrus paradisi and Citrus limon fruits to Alternaria alternata pv. citri was investigated using different artificial inoculation methods. The results obtained reveal that the C. paradisi and C. limon fruits are less susceptible to A. alternata pv. citri than Fortune fruits, although all showed symptoms of Alternaria brown spot when the cuticle was

  12. First report of Alternaria mali causing apple leaf blotch disease in Iran

    Microsoft Academic Search

    Mohammad Javad SoleimaniA; Marzieh EsmailzadehA

    A severe foliar disease was observed on apple trees in the north-western part of Iran in 2006. Symptoms included black and dark brown leaf spots on leaves of apple trees. Alternaria mali was isolated from all diseased leaves. This is the first report of Alternaria leaf blotch on apple in Iran.

  13. First report of Alternaria mali causing apple leaf blotch disease in Iran

    Microsoft Academic Search

    Mohammad Javad Soleimani; Marzieh Esmailzadeh

    2007-01-01

    A severe foliar disease was observed on apple trees in the north-western part of Iran in 2006. Symptoms included black and\\u000a dark brown leaf spots on leaves of apple trees. Alternaria mali was isolated from all diseased leaves. This is the first report of Alternaria leaf blotch on apple in Iran.

  14. Effect of Lesion Age, Humidity, and Fungicide Application on Sporulation of Alternaria alternata , the Cause of Brown Spot of Tangerine

    Microsoft Academic Search

    R. F. Reis; A. de Goes; S. N. Mondal; T. Shilts; F. C. Brentu; L. W. Timmer

    2006-01-01

    Reis, R. F., de Goes, A., Mondal, S. N., Shilts, T., Brentu, F. C., and Timmer, L. W. 2006. Effect of lesion age, humidity, and fungicide application on sporulation of Alternaria alternata, the cause of brown spot of tangerine. Plant Dis. 90:1051-1054. Alternaria brown spot, caused by Alternaria alternata, causes yield losses and fruit blemishes on many tangerines and their

  15. Modelling and visualizing morphology in the fungus Alternaria.

    PubMed

    Taralova, Ekaterina H; Schlecht, Joseph; Barnard, Kobus; Pryor, Barry M

    2011-11-01

    Alternaria is one of the most cosmopolitan fungal genera encountered and impacts humans and human activities in areas of material degradation, phytopathology, food toxicology, and respiratory disease. Contemporary methods of taxon identification rely on assessments of morphology related to sporulation, which are critical for accurate diagnostics. However, the morphology of Alternaria is quite complex, and precise characterization can be laborious, time-consuming, and often restricted to experts in this field. To make morphology characterization easier and more broadly accessible, a generalized statistical model was developed for the three-dimensional geometric structure of the sporulation apparatus. The model is inspired by the widely used grammar-based models for plants, Lindenmayer-systems, which build structure by repeated application of rules for growth. Adjusting the parameters of the underlying probability distributions yields variations in the morphology, and thus the approach provides an excellent tool for exploring the morphology of Alternaria under different assumptions, as well as understanding how it is largely the consequence of local rules for growth. Further, different choices of parameters lead to different model groups, which can then be visually compared to published descriptions or microscopy images to validate parameters for species-specific models. The approach supports automated analysis, as the models can be fit to image data using statistical inference, and the explicit representation of the geometry allows the accurate computation of any morphological quantity. Furthermore, because the model can encode the statistical variation of geometric parameters for different species, it will allow automated species identification from microscopy images using statistical inference. In summary, the approach supports visualization of morphology, automated quantification of phenotype structure, and identification based on form. PMID:22036294

  16. Chemical constituents of marine mangrove-derived endophytic fungus Alternaria tenuissima EN-192

    NASA Astrophysics Data System (ADS)

    Sun, Hong; Gao, Shushan; Li, Xiaoming; Li, Chunshun; Wang, Bingui

    2013-03-01

    A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN-192, an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa, resulted in the isolation of nine known secondary metabolites, including four indole-diterpenoids: penijanthine A ( 1), paspaline ( 2), paspalinine ( 3), and penitrem A ( 4); three tricycloalternarene derivatives: tricycloalternarene 3a ( 5), tricycloalternarene 1b ( 6), and tricycloalternarene 2b ( 7); and two alternariol congeners: djalonensone ( 8) and alternariol ( 9). The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature. The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum, with inhibition zone diameters of 8 and 9 mm, respectively, at 100 ?g/disk. To the best of our knowledge, this is the first report on the secondary metabolites of mangrove-derived A lternaria tenuissima and also the first report of the isolation of indole-diterpenoids from fungal genus A lternaria.

  17. Different Transcriptional Response to Xanthomonas citri subsp. citri between Kumquat and Sweet Orange with Contrasting Canker Tolerance

    PubMed Central

    Fu, Xing-Zheng; Gong, Xiao-Qing; Zhang, Yue-Xin; Wang, Yin; Liu, Ji-Hong

    2012-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia) is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck) is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs) were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO) annotation and Singular Enrichment Analysis (SEA) of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future. PMID:22848606

  18. Genetic diversity of citrus bacterial canker pathogens preserved in herbarium specimens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) was first documented in India and Java in the mid 19th century. Since that time the known distribution of the disease has steadily increased. Concurrent with the dispersion of the pathogen, the diversity of described str...

  19. IMAGE ANALYSIS VERSUS VISUAL ASSESSMENT OF INCIDENCE AND SEVERITY OF CITRUS CANKER SYMPTOMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv citri causes citrus canker. Disease assessment is important for monitoring epidemics. Visual assessment (VA) is presently the only reliable means of detection. To investigate how VA of symptoms compared to image analysis we used digital images of 214 citrus le...

  20. Bacterial Canker (Clavibacter michiganensis subsp. michiganensis) of tomato in commercial seed produced in Indonesia

    Microsoft Academic Search

    A. Anwar; Zouwen van der P. S; S. Ilyas; Wolf van der J. M

    2004-01-01

    In 2002, Clavibacter michiganensis subsp. michiganensis (Smith) Davis, the causal organism of bacterial canker of tomato (Lycopersicon esculentum), was isolated from two of six commercial asymptomatic tomato seed lots produced on Java in Indonesia. C. michiganensis subsp. michiganensis has not been reported in Indonesia previously. Methods based on the protocol of the International Seed Health Initiative were used to extract

  1. Enhanced tomato resistance to bacterial canker by application of turtle oil

    Microsoft Academic Search

    Ömür Baysal; Y. Ziya Gürsoy; Hakan Örnek; Ahmet Duru

    2005-01-01

    Pretreatment with oil of sea turtle Caretta caretta protected tomato plants against bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm). The turtle oil was ineffective in inhibiting Cmm in an agar diffusion test, suggesting a mechanism of induced resistance. Under controlled conditions in the greenhouse, turtle oil lowered the disease index and had reduced the growth of bacteria up

  2. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease

    Microsoft Academic Search

    Y. Hu; J. Zhang; H. Jia; D. Sosso; T. Li; W. B. Frommer; B. Yang; F. F. White; N. Wang; J. B. Jones

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector

  3. New Phomopsis species identified from wood cankers in eastern North American vineyards.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phomopsis cane and leaf spot, caused by the Ascomycete fungus Phomopsis viticola, is a destructive fruit and foliar disease in eastern North American vineyards. The pathogen typically attacks green tissues, but can also cause wood cankers, presumably due to infection of pruning wounds, as is the cas...

  4. The Eucalyptus canker pathogen Holocryphia eucalypti on Eucalyptus in New Zealand

    E-print Network

    The Eucalyptus canker pathogen Holocryphia eucalypti on Eucalyptus in New Zealand M. Gryzenhout, South Africa. C Scion Research, New Zealand Forest Institute Ltd, Rotorua, New Zealand. D Corresponding and morphological characterisation, we show for the first time that H. eucalypti is present in New Zealand

  5. Population Structure of Geosmithia morbida, the Causal Agent of Thousand Cankers Disease of Walnut Trees in

    E-print Network

    , Steven J. Seybold7 , Ned Tisserat1 1 Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America, 2 USDA Forest Service Hardwood Tree morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease

  6. REPEATABILITY AND COMPARISION OF IMAGE ANALYSIS AND VISUAL ASSESSMENT FOR DISEASE ASSESSMENT OF CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, a disease of several citrus species, is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac). The disease is of concern in several wet tropical and subtropical citrus growing regions as infection results in yield loss and severely blemished fruit unsuitable for the f...

  7. GENETIC DIVERSITY AND WORLDWIDE PROLIFERATION OF CITRUS BACTERIAL CANKER PATHOGENS IDENTIFIED IN HISTORIC SPECIMENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) may have originated in Southeast Asia, based on symptoms present on early herbarium specimens. The disease was first introduced into the United States in 1911 and has spread to most citrus producing areas in the world. Th...

  8. Update on packing line protocols for citrus canker and their effects on bacterial survival

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Markets for Florida citrus are severely restricted by regulations in place to minimize the spread of citrus canker to citrus producing areas. Included in these regulations are accepted protocols for sanitation and coating of fruit. However, these measures do not eradicate all the living bacterial ce...

  9. THE EFFECT OF HURRICANES AND TROPICAL STORMS ON LONG DISTANCE SPREAD OF CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (ACC) is a serious disease of citrus that causes foliar and fruit lesions leading to extensive yield and quality losses. During Fall 2004, Florida experienced 3 hurricanes (Charlie, Francis, Jeanne) and one tropical storm (Ivan) whose paths crossed the majority of the commercia...

  10. LONG DISTANCE SPREAD OF CITRUS CANKER RELATED TO HURRICANES AND TROPICAL STORMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (ACC) is a serious disease of citrus that causes foliar and fruit lesions leading to extensive yield and quality losses. During Fall 2004, Florida experienced 3 hurricanes (Charlie, Francis, Jeanne) and one tropical storm (Ivan) whose paths crossed the majority of the commercia...

  11. Characterization of Pear Blister Canker Viroid Isolates from Australian Pome Fruit Orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pear blister canker viroid (PBCVd) was detected in pear (Pyrus sp.), nashi (Pyrus serotina) and quince (Cydonia oblonga) trees from various pome fruit growing regions of Australia using dot-blot hybridization and RT-PCR techniques. Characteristic symptoms of PBCVd infection were not observed on the...

  12. Mold and Alternaria skin test reactivity and asthma in children in Connecticut

    PubMed Central

    Lyons, Todd W.; Wakefield, Dorothy B.; Cloutier, Michelle M.

    2013-01-01

    Background Sensitivity to mold has been associated with asthma incidence, persistence, and severity. Objective To examine the relationship between skin test reactivity (STR) to molds and specifically to Alternaria and asthma severity in a group of ethnically diverse children in Connecticut. Methods Demographics and STR to 14 local allergens, including Alternaria, Penicillium, and mold mix, were obtained for 914 Puerto Rican, African American, and non-Hispanic white children. Results A total of 126 children (14%) had a positive skin test result to mold, and 58 (6%) demonstrated STR to Alternaria. Compared with non-Hispanic white children, there was no difference in the likelihood of being sensitized to Alternaria for Puerto Rican and African American children (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.3–1.5; and OR, 0.9; 95% CI, 0.4–2.2; respectively). In an adjusted analysis, Alternaria STR was associated with severe, persistent asthma (OR, 3.4; 95% CI, 1.2–8.6) but did not predict increasing asthma severity. STR to cat (OR, 2.5; 95% CI, 1.3–4.9) and dog (OR, 2.9; 95% CI, 1.3–6.0) was also associated with severe persistent asthma. Alternaria STR was associated with severe persistent asthma independent of the total number of positive skin test results. Conclusions Mold and Alternaria STR were uncommon among children in Connecticut. Alternaria STR was not associated with increasing asthma severity but was associated with severe, persistent asthma independent of the total number of positive skin test results. There was no association between ethnicity and Alternaria STR. PMID:21457878

  13. Citrus MAF1, a Repressor of RNA Polymerase III, Binds the Xanthomonas citri Canker Elicitor PthA4 and Suppresses Citrus Canker Development1

    PubMed Central

    Soprano, Adriana Santos; Abe, Valeria Yukari; Smetana, Juliana Helena Costa; Benedetti, Celso Eduardo

    2013-01-01

    Transcription activator-like (TAL) effectors from Xanthomonas species pathogens act as transcription factors in plant cells; however, how TAL effectors activate host transcription is unknown. We found previously that TAL effectors of the citrus canker pathogen Xanthomonas citri, known as PthAs, bind the carboxyl-terminal domain of the sweet orange (Citrus sinensis) RNA polymerase II (Pol II) and inhibit the activity of CsCYP, a cyclophilin associated with the carboxyl-terminal domain of the citrus RNA Pol II that functions as a negative regulator of cell growth. Here, we show that PthA4 specifically interacted with the sweet orange MAF1 (CsMAF1) protein, an RNA polymerase III (Pol III) repressor that controls ribosome biogenesis and cell growth in yeast (Saccharomyces cerevisiae) and human. CsMAF1 bound the human RNA Pol III and rescued the yeast maf1 mutant by repressing tRNAHis transcription. The expression of PthA4 in the maf1 mutant slightly restored tRNAHis synthesis, indicating that PthA4 counteracts CsMAF1 activity. In addition, we show that sweet orange RNA interference plants with reduced CsMAF1 levels displayed a dramatic increase in tRNA transcription and a marked phenotype of cell proliferation during canker formation. Conversely, CsMAF1 overexpression was detrimental to seedling growth, inhibited tRNA synthesis, and attenuated canker development. Furthermore, we found that PthA4 is required to elicit cankers in sweet orange leaves and that depletion of CsMAF1 in X. citri-infected tissues correlates with the development of hyperplastic lesions and the presence of PthA4. Considering that CsMAF1 and CsCYP function as canker suppressors in sweet orange, our data indicate that TAL effectors from X. citri target negative regulators of RNA Pol II and Pol III to coordinately increase the transcription of host genes involved in ribosome biogenesis and cell proliferation. PMID:23898043

  14. Occurrence of Leaf Blight on Cosmos Caused by Alternaria cosmosa in Korea

    PubMed Central

    Deng, Jian Xin; Lee, Ji Hye; Paul, Narayan Chandra; Cho, Hye Sun; Lee, Hyang Burm; Yu, Seung Hun

    2015-01-01

    In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus) leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea. PMID:25774114

  15. Occurrence of Leaf Blight on Cosmos Caused by Alternaria cosmosa in Korea.

    PubMed

    Deng, Jian Xin; Lee, Ji Hye; Paul, Narayan Chandra; Cho, Hye Sun; Lee, Hyang Burm; Yu, Seung Hun

    2015-03-01

    In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus) leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea. PMID:25774114

  16. Alternaria-derived serine protease activity drives IL-33–mediated asthma exacerbations

    PubMed Central

    Snelgrove, Robert J.; Gregory, Lisa G.; Peiró, Teresa; Akthar, Samia; Campbell, Gaynor A.; Walker, Simone A.; Lloyd, Clare M.

    2014-01-01

    Background The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. Objective We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. Methods IL-33 levels were quantified in wild-type and ST2?/? mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later. Results Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease–IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model. Conclusion Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease. PMID:24636086

  17. Distribution and Characterization of AKT Homologs in the Tangerine Pathotype of Alternaria alternata

    Microsoft Academic Search

    A. Masunaka; A. Tanaka; T. Tsuge; T. L. Peever; L. W. Timmer; M. Yamamoto; H. Yamamoto; K. Akimitsu

    2000-01-01

    Masunaka, A., Tanaka, A., Tsuge, T., Peever, T. L., Timmer, L. W., Yamamoto, M., Yamamoto, H., and Akimitsu, K. 2000. Distribution and characterization of AKT homologs in the tangerine pathotype of Alter- naria alternata. Phytopathology 90:762-768. The tangerine pathotype of Alternaria alternata produces a host-se- lective toxin (HST), known as ACT-toxin, and causes Alternaria brown spot disease of citrus. The

  18. The effect of runoff on spray deposition and control of Alternaria brown spot of mandarins

    Microsoft Academic Search

    P. H. Fourie; M. du Preez; J. C. Brink; G. C. Schutte

    2009-01-01

    Alternaria alternata pv. citri is the causal agent of Alternaria brown spot on tangerines and their hybrids and infects young leaves and fruit of all ages.\\u000a In South Africa, repeated high volume (?9000 L\\/ha) fungicide sprays on susceptible cultivars are the only effective control\\u000a measure of this disease. The effect of runoff on spray deposition and biological efficacy was largely

  19. Alternaria alternata from oilseed rape: mycotoxin production, and toxicity to Artemia salina larvae and rape seedlings

    Microsoft Academic Search

    A Visconti; A Sibilia; C Sabia

    1992-01-01

    Summary  A survey, carried out in Southern Italy on fungi colonizing oilseed rape (Brassicae napua L subspoleifera DC) in the field, showedAlternaria alternata (Fries) Keissler as one of the predominant species. 11 strains ofAlternaria alternata isolated from oilseed rape were cultured on rice to test the ability to produce mycotoxins. All strains produced mycotoxins,\\u000a including tenuazonic acid (up to 12,000mg\\/kg), alternariol

  20. Mycosphaerellaceae and Teratosphaeriaceae associated with Eucalyptus leaf diseases and stem cankers in Uruguay

    E-print Network

    Blanchette, Robert A.

    in Uruguay By C. A. Pe´rez1,2,5 , M. J. Wingfield3 , N. A. Altier4 and R. A. Blanchette1 1 Department´, Uruguay; 3 Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Uruguay; 5 E-mail: caperez@fagro.edu.uy (for correspondence) Summary Mycosphaerella leaf diseases

  1. Characterization of Alternaria strains from Argentinean blueberry, tomato, walnut and wheat.

    PubMed

    Andersen, Birgitte; Nielsen, Kristian F; Fernández Pinto, Virginia; Patriarca, Andrea

    2015-03-01

    Alternaria species have the ability to produce a variety of secondary metabolite, which plays important roles in food safety. Argentina is the second largest exporter of fresh and processed food products to Europe, however, few studies on Alternaria mycotoxins and other bioactive secondary metabolites have been carried out on Argentinean cereals, fruit and vegetables. Knowing the full chemical potential and the distribution of Alternaria spp. on crops, it is necessary to establish a toxicological risk assessment for food products for human consumption. In the present study, 87 Alternaria strains from different substrates (tomato, wheat, blueberries and walnuts) were characterized according to morphology and metabolite production. Aggressive dereplication (accurate mass, isotopic patterns and lists of all described compounds from Alternaria) was used for high-throughput evaluation of the chemical potential. Four strains belonged to the Alternaria infectoria sp.-grp., 6 to the Alternaria arborescens sp.-grp., 6 showed a sporulation pattern similar to that of "M" according to Simmons, 1 to that of Alternaria vaccinii, and the remaining 70 constituted a diverse group belonging to morphological groups "G" and "H". The cluster analysis yielded 16 almost identical dendrograms and grouped the Alternaria strains into four clusters and 11 singletons and outlier groups. The chemical analysis showed that AOH and AME were the most common metabolites produced, followed by TEN, ALXs and TeA. The A. infectoria sp.-grp. had no metabolites in common with the rest of the strains. Several secondary metabolites isolated from large-spored Alternaria species or other fungal genera were detected, such as dehydrocurvularin, pyrenochaetic acid and alternarienonic acid. The strains isolated from tomato produced lower amounts of metabolites than strains from blueberries, walnut and wheat, although individual strains from tomato produced the highest amount of some metabolites. The A. infectoria sp.-grp. was unique to cereals, whereas strains classified as belonging to the A. arborescens sp.-grp or having sporulation pattern "M" were only isolated from tomatoes. Otherwise, no clear association between substrate and identity could be found. The analyses in the study show that at least 75% of the Argentinean strains are able to produce potential mycotoxins. PMID:25498470

  2. Hyperspectral and Thermal Imaging of Oilseed Rape (Brassica napus) Response to Fungal Species of the Genus Alternaria

    PubMed Central

    Baranowski, Piotr; Jedryczka, Malgorzata; Mazurek, Wojciech; Babula-Skowronska, Danuta; Siedliska, Anna; Kaczmarek, Joanna

    2015-01-01

    In this paper, thermal (8-13 µm) and hyperspectral imaging in visible and near infrared (VNIR) and short wavelength infrared (SWIR) ranges were used to elaborate a method of early detection of biotic stresses caused by fungal species belonging to the genus Alternaria that were host (Alternaria alternata, Alternaria brassicae, and Alternaria brassicicola) and non-host (Alternaria dauci) pathogens to oilseed rape (Brassica napus L.). The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics. Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants. The significant differences in leaf temperature of the studied Alternaria species were observed in various stages of infection development. The classification experiments were performed on the hyperspectral data of the leaf surfaces to distinguish days after inoculation and Alternaria species. The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%). PMID:25826369

  3. Hyperspectral and thermal imaging of oilseed rape (Brassica napus) response to fungal species of the genus Alternaria.

    PubMed

    Baranowski, Piotr; Jedryczka, Malgorzata; Mazurek, Wojciech; Babula-Skowronska, Danuta; Siedliska, Anna; Kaczmarek, Joanna

    2015-01-01

    In this paper, thermal (8-13 µm) and hyperspectral imaging in visible and near infrared (VNIR) and short wavelength infrared (SWIR) ranges were used to elaborate a method of early detection of biotic stresses caused by fungal species belonging to the genus Alternaria that were host (Alternaria alternata, Alternaria brassicae, and Alternaria brassicicola) and non-host (Alternaria dauci) pathogens to oilseed rape (Brassica napus L.). The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics. Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants. The significant differences in leaf temperature of the studied Alternaria species were observed in various stages of infection development. The classification experiments were performed on the hyperspectral data of the leaf surfaces to distinguish days after inoculation and Alternaria species. The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%). PMID:25826369

  4. Status of Citrus Canker Caused by Xanthomonas axonopodis PV. CITRI in Peninsular Malaysia

    Microsoft Academic Search

    ESHETU DERSO; KAMARUZAMAN SIJAM; ZAINAL ABIDIN; MIOR AHMAD; IBRAHIM OMAR

    Study on citrus canker caused by Xanthomonas axonopodis pv. citri was undertaken in Peninsular Malaysia. The disease occurred in eight states, where incidence of 36.5% and severity of 15.2% was observed on leaves, while incidence of 18.7% and severity of 7.5% was observed on fruits. Field host range included Mexican lime (C. aurantifolia), pomelo (C. grandis) and kaffier lime (C.

  5. QCM immunoassay for recombinant cysteine peptidase: a potential protein biomarker for diagnosis of citrus canker.

    PubMed

    Afonso, André S; Zanetti, Bianca F; Santiago, Adelita C; Henrique-Silva, Flavio; Mattoso, Luiz H C; Faria, Ronaldo C

    2013-01-30

    Citrus canker is one of the most important agricultural citrus diseases worldwide. It is caused by Xanthomonas citri subsp. citri (Xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (CPXaC), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. We report here the studies on the development of piezoelectric immunoassay for CPXaC using a polyclonal antibody against CPXaC (anti-CPXaC). Three different strategies for covalent immobilization of anti-CPXaC on gold surfaces were evaluated by monitoring the frequency (?f) and energy dissipation (?D) variation in real time when 64.5×10(-8) mol L(-1) CPXaC was added. Anti-CPXaC immobilized with 11-mercaptoundecanoic acid (MUA) showed the best relation between the frequency and dissipation factor variation, and strong values for the kinetic and equilibrium binding constant were obtained. The immunosensor showed a detection limit of 13.0 nmol L(-1) with excellent specificity, showing no response for different proteins that include another cysteine peptidase that is used as a target to detect Xylella fastidiosa bacterium, responsible for another important citrus disease. These results provide good perspectives for the use of CPXaC as a new biomarker for citrus canker. PMID:23597909

  6. Identification, characterization and mycotoxigenic ability of Alternaria spp. causing core rot of apple fruit in Greece.

    PubMed

    Ntasiou, Panagiota; Myresiotis, Charalampos; Konstantinou, Sotiris; Papadopoulou-Mourkidou, Euphemia; Karaoglanidis, George S

    2015-03-16

    Alternaria core rot is a major postharvest disease of apple fruit in several countries of the world, including Greece. The study was conducted aiming to identify the disease causal agents at species level, investigate the aggressiveness of Alternaria spp. isolates and the susceptibility of different apple varieties and determine the mycotoxigenic potential of Alternaria spp. isolates from apple fruit. Seventy-five Alternaria spp. isolates obtained from apple fruit showing core rot symptoms were identified as either Alternaria tenuissima or Alternaria arborescens at frequencies of 89.3 and 11.7%, respectively, based on the sequence of endopolygalacturonase (EndoPG) gene. Artificial inoculations of fruit of 4 different varieties (Fuji, Golden Delicious, Granny Smith and Red Delicious) and incubation at two different temperatures (2 and 25°C) showed that fruit of Fuji variety were the most susceptible and fruit of Golden Delicious the most resistant to both pathogens. In addition, the production of 3 mycotoxins, alternariol (AOH), alternariol monomethyl ether (AME) and tentoxin (TEN) was investigated in 30 isolates of both species. Mycotoxin determination was conducted both in vitro, on artificial nutrient medium and in vivo on artificially inoculated apple fruit, using a high performance liquid chromatography with diode array detector (HPLC-DAD). The results showed that most of the isolates of both species were able to produce all the 3 metabolites both in vivo and in vitro. On apple fruit A. tenuissima isolates produced more AOH than A. arborescens isolates, whereas the latter produced more TEN than the former. Such results indicate that Alternaria core rot represents a major threat of apple fruit production not only due to quantitative yield losses but also for qualitative deterioration of apple by-products. PMID:25560914

  7. DEVELOPMENT OF A PCR-BASED METHOD FOR THE DETECTION OF BRENNARIA RUBRIFACIENS; THE CAUSAL AGENT OF DEEP BARK CANKER OF WALNUT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deep Bark Canker (DBC), caused by the bacterium Brenneria rubrifaciens (previously known as Erwinia rubrifaciens), afflicts English walnut cultivars and is characterized by late onset of symptoms in trees greater than 15 years old. These symptoms include deep bleeding vertical cankers throughout th...

  8. Activity of citrus canker lesions on leaves, shoots and fruit of grapefruit in a Florida orchard from June 2010 to January 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lesions of citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), on citrus fruit preclude export to certain markets. Characterizing the population dynamics of bacteria in canker lesions in commercial orchards can help gauge risk associated with diseased fruit entering fresh markets. The aim...

  9. The effect of wind on dispersal of splash-borne Xanthomonas citri subsp citri at different heights and distances downwind of canker-infected grapefruit trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri subsp citri (Xcc), which causes citrus canker, is a major pathogen of grapefruit and other canker-susceptible citrus species and cultivars grown in Florida and elsewhere. It is dispersed by rain splash, and wind promotes the dispersal of the pathogen. The aim of this study was to e...

  10. First Report of Nectria galligena Causing European Canker of Apple Trees in Ontario. A. R. Biggs, Agriculture Canada Research Station, Vineland Station, Ontario LOR 2EO. Plant

    E-print Network

    Biggs, Alan R.

    First Report of Nectria galligena Causing European Canker of Apple Trees in Ontario. A. R. Biggs for publication 19 July 1985. European canker of apple (Malus domestics Borkh. 'MacIntosh') caused by Nectria includes the apple-growing region of central Ontario. Reference: Booth, C. Commonw. Mycol. Inst. Pap. 73

  11. Genetic variability of Brazilian isolates of Alternaria alternata detected by AFLP and RAPD techniques

    PubMed Central

    Dini-Andreote, Francisco; Pietrobon, Vivian Cristina; Andreote, Fernando Dini; Romão, Aline Silva; Spósito, Marcel Bellato; Araújo, Welington Luiz

    2009-01-01

    The Alternaria brown spot (ABS) is a disease caused in tangerine plants and its hybrids by the fungus Alternaria alternata f. sp. citri which has been found in Brazil since 2001. Due to the recent occurrence in Brazilian orchards, the epidemiology and genetic variability of this pathogen is still an issue to be addressed. Here it is presented a survey about the genetic variability of this fungus by the characterization of twenty four pathogenic isolates of A. alternata f. sp. citri from citrus plants and four endophytic isolates from mango (one Alternaria tenuissima and three Alternaria arborescens). The application of two molecular markers Random Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphism (AFLP) had revealed the isolates clustering in distinct groups when fingerprintings were analyzed by Principal Components Analysis (PCA). Despite the better assessment of the genetic variability through the AFLP, significant modifications in clusters components were not observed, and only slight shifts in the positioning of isolates LRS 39/3 and 25M were observed in PCA plots. Furthermore, in both analyses, only the isolates from lemon plants revealed to be clustered, differently from the absence of clustering for other hosts or plant tissues. Summarizing, both RAPD and AFLP analyses were both efficient to detect the genetic variability within the population of the pathogenic fungus Alternaria spp., supplying information on the genetic variability of this species as a basis for further studies aiming the disease control. PMID:24031413

  12. Genetic variability of Brazilian isolates of Alternaria alternata detected by AFLP and RAPD techniques.

    PubMed

    Dini-Andreote, Francisco; Pietrobon, Vivian Cristina; Andreote, Fernando Dini; Romão, Aline Silva; Spósito, Marcel Bellato; Araújo, Welington Luiz

    2009-07-01

    The Alternaria brown spot (ABS) is a disease caused in tangerine plants and its hybrids by the fungus Alternaria alternata f. sp. citri which has been found in Brazil since 2001. Due to the recent occurrence in Brazilian orchards, the epidemiology and genetic variability of this pathogen is still an issue to be addressed. Here it is presented a survey about the genetic variability of this fungus by the characterization of twenty four pathogenic isolates of A. alternata f. sp. citri from citrus plants and four endophytic isolates from mango (one Alternaria tenuissima and three Alternaria arborescens). The application of two molecular markers Random Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphism (AFLP) had revealed the isolates clustering in distinct groups when fingerprintings were analyzed by Principal Components Analysis (PCA). Despite the better assessment of the genetic variability through the AFLP, significant modifications in clusters components were not observed, and only slight shifts in the positioning of isolates LRS 39/3 and 25M were observed in PCA plots. Furthermore, in both analyses, only the isolates from lemon plants revealed to be clustered, differently from the absence of clustering for other hosts or plant tissues. Summarizing, both RAPD and AFLP analyses were both efficient to detect the genetic variability within the population of the pathogenic fungus Alternaria spp., supplying information on the genetic variability of this species as a basis for further studies aiming the disease control. PMID:24031413

  13. An Isolate of Alternaria alternata That Is Pathogenic to Both Tangerines and Rough Lemon and Produces Two Host-Selective Toxins, ACT and ACR-Toxins

    Microsoft Academic Search

    A. Masunaka; K. Ohtani; T. L. Peever; L. W. Timmer; T. Tsuge; M. Yamamoto; H. Yamamoto; K. Akimitsu

    2005-01-01

    Masunaka, A., Ohtani, K., Peever, T. L., Timmer, L. W., Tsuge, T., Yamamoto, M., Yamamoto, H., and Akimitsu, K. 2005. An isolate of Alternaria alternata that is pathogenic to both tangerines and rough lemon and produces two host-selective toxins, ACT- and ACR-toxins. Phytopathology 95:241-247. Two different pathotypes of Alternaria alternata cause Alternaria brown spot of tangerines and Alternaria leaf spot

  14. Light and Scanning Electron Microscopy Studies on the Penetration and Infection Processes of Alternaria Alternata, Causing Brown Spot on Minneola Tangelo in the West Mazandaran - Iran

    Microsoft Academic Search

    A. A. Dehpour; S. V. Alavi; A. Majd

    Alternaria fungi causes two different diseases on citrus in Mazandaran province, North of Iran: Alternaria brown spot of tangerine hybrids and Alternaria black rot of the Navel orange fruit. A. alternata, conidium germination, Inoculation, penetration and colonization on the plant surfaces studied using light and electrone microscopies. The tissues cutted to (2×2 mm) pieces and were fixed over night at

  15. Evaluation of the Alter-Rater model for spray timing for control of Alternaria brown spot on Murcott tangor in Brazil

    Microsoft Academic Search

    N. A. Peres; L. W. Timmer

    2006-01-01

    Alternaria brown spot, caused by Alternaria alternata, recently appeared in Brazil and is now causing serious damage to Murcott tangors in São Paulo State. The Alter-Rater model and other systems for timing fungicide applications as well as different fungicide programs were evaluated in two seasons in different citrus-growing areas of São Paulo State. Alternaria brown spot severely reduced yields of

  16. Alt a 1 from Alternaria interacts with PR5 thaumatin-like proteins.

    PubMed

    Gómez-Casado, Cristina; Murua-García, Amaya; Garrido-Arandia, María; González-Melendi, Pablo; Sánchez-Monge, Rosa; Barber, Domingo; Pacios, Luis F; Díaz-Perales, Araceli

    2014-05-01

    Alt a 1 is a protein found in Alternaria alternata spores related to virulence and pathogenicity and considered to be responsible for chronic asthma in children. We found that spores of Alternaria inoculated on the outer surface of kiwifruits did not develop hyphae. Nevertheless, the expression of Alt a 1 gene was upregulated, and the protein was detected in the pulp where it co-localized with kiwi PR5. Pull-down assays demonstrated experimentally that the two proteins interact in such a way that Alt a 1 inhibits the enzymatic activity of PR5. These results are relevant not only for plant defense, but also for human health as patients with chronic asthma could suffer from an allergic reaction when they eat fruit contaminated with Alternaria. PMID:24642375

  17. Bacterial canker of plum trees, caused by Pseudomonas syringae pathovars, as a serious threat for plum production in the Netherlands.

    PubMed

    Wenneker, M; Janse, J D; De Bruine, J A

    2011-01-01

    In the Netherlands, bacterial canker in plum trees (Prunus domestica) is a serious and recent problem in plum production. It is caused by Pseudomonas syringae pathovars syringae and morsprunorum. The trunks of the affected plum trees are girdled by bacterial cankers resulting in sudden death of infected trees in 3-4 years after planting. Disease incidences can be very high, and sometimes complete orchards have to be removed. Recently, plum cultivation in the Netherlands has changed from a relatively extensive into an intensive cultivation. However, due to the risks of losses of trees due to bacterial canker, growers are reluctant to plant new plum orchards. In general nurseries and fruit growers are not familiar with bacterial diseases and lack knowledge in order to prevent infections. Therefore, control strategies to manage plum decline have to be developed. PMID:22702175

  18. Molecular, ecological and evolutionary approaches to understanding Alternaria diseases of citrus.

    PubMed

    Akimitsu, Kazuya; Peever, Tobin L; Timmer, L W

    2003-11-01

    SUMMARY Alternaria fungi cause four different diseases of citrus: Alternaria brown spot of tangerines, Alternaria leaf spot of rough lemon, Alternaria black rot of several citrus fruits and Mancha foliar of Mexican lime. The first three diseases are caused by the small-spored species, Alternaria alternata and the causal agents can only be differentiated using pathogenicity tests, toxin assays or genetic markers. Mancha foliar is caused by the morphologically distinct, large-spored species A. limicola. Substantial progress has been made in understanding the biology, ecology, population biology, systematics, molecular biology and biochemistry of the interactions between these pathogens and citrus. Epidemiological studies have focused on brown spot of tangerines and their hybrids and have contributed to the development of a model of disease development which has improved control and reduced fungicide use. Studies of the population genetics, host specificity and ecology of A. alternata from different ecological niches on citrus have revealed host specific forms of the pathogen which cause disease on different citrus species, the existence of three phylogenetic lineages of the fungus which cause brown spot world-wide, and closely related non-pathogenic isolates which colonize healthy citrus tissue. The role of host-specific toxins in Alternaria diseases of citrus has been extensively studied for over 20 years, and these pathosystems have become model systems for host-pathogen interactions. Recent molecular research has started to unravel the genetic basis of toxin production and the host susceptibility to toxin, and the role of extracellular, degradative enzymes in disease. PMID:20569403

  19. Characterization and Pathogenicity of Alternaria vanuatuensis, a New Record from Allium Plants in Korea and China

    PubMed Central

    Li, Mei Jia; Deng, Jian Xin; Paul, Narayan Chandra

    2014-01-01

    Alternaria from different Allium plants was characterized by multilocus sequence analysis. Based on sequences of the ?-tubulin (BT2b), the Alternaria allergen a1 (Alt a1), and the RNA polymerase II second largest subunit (RPB2) genes and phylogenetic data analysis, isolates were divided into two groups. The two groups were identical to representative isolates of A. porri (EGS48-147) and A. vanuatuensis (EGS45-018). The conidial characteristics and pathogenicity of A. vanuatuensis also well supported the molecular characteristics. This is the first record of A. vanuatuensis E. G. Simmons & C. F. Hill from Korea and China. PMID:25606017

  20. Characterization and Pathogenicity of Alternaria vanuatuensis, a New Record from Allium Plants in Korea and China.

    PubMed

    Li, Mei Jia; Deng, Jian Xin; Paul, Narayan Chandra; Lee, Hyang Burm; Yu, Seung Hun

    2014-12-01

    Alternaria from different Allium plants was characterized by multilocus sequence analysis. Based on sequences of the ?-tubulin (BT2b), the Alternaria allergen a1 (Alt a1), and the RNA polymerase II second largest subunit (RPB2) genes and phylogenetic data analysis, isolates were divided into two groups. The two groups were identical to representative isolates of A. porri (EGS48-147) and A. vanuatuensis (EGS45-018). The conidial characteristics and pathogenicity of A. vanuatuensis also well supported the molecular characteristics. This is the first record of A. vanuatuensis E. G. Simmons & C. F. Hill from Korea and China. PMID:25606017

  1. Proteome Analysis of Pathogen-Responsive Proteins from Apple Leaves Induced by the Alternaria Blotch Alternaria alternata

    PubMed Central

    Zhang, Cai-xia; Tian, Yi; Cong, Pei-hua

    2015-01-01

    Understanding the defence mechanisms used by apple leaves against Alternaria alternate pathogen infection is important for breeding purposes. To investigate the ultrastructural differences between leaf tissues of susceptible and resistant seedlings, in vitro inoculation assays and transmission electron microscopy (TEM) analysis were conducted with two different inoculation assays. The results indicated that the resistant leaves may have certain antifungal activity against A. alternate that is lacking in susceptible leaves. To elucidate the two different host responses to A. alternate infection in apples, the proteomes of susceptible and resistant apple leaves that had or had not been infected with pathogen were characterised using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS). MS identified 43 differentially expressed proteins in two different inoculation assays. The known proteins were categorised into 5 classes, among these proteins, some pathogenesis-related (PR) proteins, such as beta-1,3-glucanase, ascorbate peroxidase (APX), glutathione peroxidase (GPX) and mal d1, were identified in susceptible and resistant hosts and were associated with disease resistance of the apple host. In addition, the different levels of mal d1 in susceptible and resistant hosts may contribute to the outstanding anti-disease properties of resistant leaves against A. alternate. Taken together, the resistance mechanisms of the apple host against A. alternate may be a result of the PR proteins and other defence-related proteins. Given the complexity of the biology involved in the interaction between apple leaves and the A. alternate pathogen, further investigation will yield more valuable insights into the molecular mechanisms of suppression of the A. alternate pathogen. Overall, we outline several novel insights into the response of apple leaves to pathogen attacks. These findings increase our knowledge of pathogen resistance mechanisms, and the data will also promote further investigation into the regulation of the expression of these target proteins. PMID:26086845

  2. Dieback and sooty canker of Ficus trees in Egypt and its control.

    PubMed

    Abo Rehab, M E A; Rashed, M F; Ammar, M I; El-Morsy, S A

    2014-02-01

    This study was designed to throw lights on dieback and canker disease on urban trees of Ficus sp. in Egypt, its causal pathogens and disease control. Diseased samples were collected from five locations. Pathogenicity test was done on one year old of three different healthy seedlings of Ficus trees (Ficus benghalensis, Ficu snitida and Ficus hawaii). Lasiodiplodia theobromae and Phomopsis sp. were consistently isolated from infected tissues and were pathogenic. The fungicides Antracol Combi and Topsin M 70 provided effective control of the infection. Accordingly, protecting ficus trees from diseases threating is considered a major goal to attain their benefits. PMID:24897790

  3. Worldwide Phylogeography of the Citrus Brown Spot Pathogen, Alternaria alternata.

    PubMed

    Peever, T L; Ibañez, A; Akimitsu, K; Timmer, L W

    2002-07-01

    ABSTRACT Sixty-five isolates of Alternaria alternata were sampled from brown spot lesions on tangerines and mandarins (Citrus reticulata) and tangerine x grapefruit (C. reticulata x C. paradisi) hybrids in the United States, Colombia, Australia, Turkey, South Africa, and Israel to investigate the worldwide phylogeography of the fungus. Genetic variation was scored at 15 putative random amplified polymorphic DNA (RAPD) loci and 465 bp of an endo-polygalacturonase (endo-PG) gene was sequenced for each isolate. Cluster analysis of RAPD genotypes revealed significant differentiation between United State and Colombia isolates and Turkey, South Africa, Israel, and Australia isolates. Sequencing of endo-PG revealed 21 variable sites when the outgroup A. gaisen (AK-toxin-producing pathogen of Japanese pear) was included and 13 variable sites among the sampled isolates. Nucleotide substitutions at 10 of 13 variable sites represented silent mutations when endo-PG was translated in frame. Eight distinct endo-PG haplotypes were found among the sampled isolates and estimation of a phylogeny with endo-PG sequence data revealed three clades, each with strong bootstrap support. The most basal clade (clade 1) was inferred based on its similarity to the outgroup A. gaisen and consisted exclusively of pathogenic isolates from the United States and Colombia. Clade 2 consisted of pathogenic and nonpathogenic isolates from the United States, Australia, South Africa, and Israel and clade 3 contained pathogenic and nonpathogenic isolates from Australia, South Africa, Israel, and Turkey. Quantitative estimates of virulence (disease incidence) were obtained for isolates from the United States, Colombia, South Africa, Israel, and Turkey by spray inoculating detached citrus leaves and counting the number of lesions 24 h after inoculation. Large differences in virulence were detected among isolates within each location and isolates from the United States were significantly more virulent than isolates from other locations. Several isolates from Colombia, South Africa, Israel, and Turkey had low virulence and 8% of all isolates were nonpathogenic. All but one of the nonpathogenic isolates were found in clade 2 of the endo-PG phylogeny, which also included the most highly virulent isolates sampled. PMID:18943277

  4. Analysis of genetic and pathogenic variation among Alternaria solani in a potato production region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year survey was conducted in a potato production region to investigate the genetic variability within naturally infecting populations of Alternaria solani, the cause of early blight in potato, and between species A. solani and A. dauci. Genetic diversity among 151 isolates was assessed using s...

  5. Resistance to alternaria solani in hybrids between a Solanum tuberosum haploid and S. raphanifolium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato (Solanum tuberosum L.), caused by the foliar fungal pathogen Alternaria solani is a major cause of economic loss in many potato growing regions. Genetic resistance offers an opportunity to decrease fungicide usage while maintaining yield and quality. In this study, an early bl...

  6. Biocontrol of Alternaria triticina by plant growth promoting rhizobacteria on wheat

    Microsoft Academic Search

    Z. A. Siddiqui

    2007-01-01

    Eighteen isolates of fluorescent pseudomonads and Bacillus spp. were isolated from Alternaria triticina suppressive soils of wheat fields. These isolates were evaluated in the laboratory and greenhouse for the biocontrol of A. triticina. Six isolates were considered to have potential for the biocontrol of A. triticina on the basis of antibiotic sensitivity, fluorescence produced by Pseudomonas, inhibitory effect on A.

  7. Antileukemic alpha-pyrone derivatives from the endophytic fungus Alternaria phragmospora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four new (1–4) and two known (5 and 6)a-pyrone derivatives have been isolated from Alternaria phragmospora, an endophytic fungus from Vinca rosea, leaves. The isolated compounds were chemically identi'ed to be 5-butyl-4-methoxy-6-methyl-2H-pyran-2-one (2) 5-butyl-6-(hydroxymethyl)-4-methoxy-2H-py...

  8. Molecular Cloning of IgE–Binding Fragments of Alternaria alternata Allergens

    Microsoft Academic Search

    Michael W. De Vouge; Ajay J. Thaker; Lei Zhang; Gauri Muradia; Harold Rode; Hari M. Vijay

    1998-01-01

    Exposure to the hyphomycete Alternaria alternata is recognized as an important risk factor for asthma. IgE immunoblotting has been used to catalogue the number and Mr of allergens in A. alternata extracts, with estimates ranging from 10 to 30, although few are present in nearly all extracts studied. Several A. alternata allergens have been cloned, including a subunit of the

  9. Antifungal activity of several medicinal plants extracts against the early blight pathogen (Alternaria solani)

    Microsoft Academic Search

    Saba J. Goussous; Firas M. Abu el-Samen; Ragheb A. Tahhan

    2010-01-01

    The antifungal activity for several medicinal plants against the early blight fungus (Alternaria solani) has been investigated. These plants were Syrian marjoram (Majorana syriaca), rosemary (Rosmarinus officinalis), Greek sage (Salvia fruticosa), roselle (Hibiscus sabdariffa) and cotton lavender (Santolina chamaecyparissus). The inhibitory effect of these extracts on the radial mycelial growth as well as on spore germination was measured in vitro

  10. The phytoalexin camalexin is not metabolized by Phoma lingam, Alternaria brassicae, or phytopathogenic bacteria

    Microsoft Academic Search

    M. Soledade C. Pedras; Abdul Q. Khan; Janet L. Taylor

    1998-01-01

    The metabolism of the cruciferous phytoalexin camalexin by the blackleg (Leptosphaeria maculans (Desm.) Ces. et de Not., asexual stage Phoma lingam (Tode ex Fr.) Desm), and blackspot (Alternaria brassicae (Berk.) Sacc.) fungi, as well as the phytopathogenic bacteria Pseudomonas syringae, P. cichorii, Erwinia carotovora, and Xanthomonas campestris was evaluated. The micro-organisms were incubated with camalexin for different time periods and

  11. Tall fescue is a potential spillover reservoir host for Alternaria species.

    PubMed

    Wilson, Hannah E; Carroll, George C; Roy, Bitty A; Blaisdell, G Kai

    2014-01-01

    The spread of invasive species is complicated and multifaceted. Enemy spillover (i.e. the transfer of a natural enemy from a reservoir host to a novel host) is one mechanism that facilitates the spread of non-native species. The reservoir host is a species that harbors high abundance of the enemy with little cost to fitness. We asked whether Schedonorus arundinaceus (tall fescue), a highly invasive grass species in North America, is a potential reservoir host for the ubiquitous genus of fungi, Alternaria. We also asked whether spillover of Alternaria is possible among grasses that commonly occur with S. arundinaceus in grassland ecosystems. We performed a greenhouse cross inoculation of three isolates of Alternaria and six grass species (three native, three invasive, including S. arundinaceus). We determined that spillover is possible because the fungal isolates infected and caused disease symptoms on all six grasses and decreased biomass in two of the grass species. We also determined that the invasive grass species appear to be more competent hosts than the native species and that S. arundinaceus could be a likely reservoir host for Alternaria spp. because it can harbor the pathogen with no apparent fitness cost. PMID:24603832

  12. A Potent Chitinolytic Activity of Alternaria alternata Isolated from Egyptian Black Sand

    Microsoft Academic Search

    EMAN FATHI SHARAF

    2005-01-01

    Eight fungal species characterized by chitinolytic activity were isolated from Egyptian black sand collected from Rosetta coast. Genus Aspergillus and Alternaria alternata exhibited the highest density (> 40% of the total count, each) on the isolation plates containing different treatments of native shrimp shell chitin. Genus Aspergillus was represented by A. flavus, A. niger, A. foetidus and A. ungius, with

  13. Seasonal Distribution of Alternaria, Aspergillus, Cladosporium and Penicillium Species Isolated in Homes of Fungal Allergic Patients

    Microsoft Academic Search

    S Gómez de An; JM Torres-Rodríguez; E Alvarado Ramírez

    Background: Allergy to airborne fungi can cause rhinitis and severe asthma, hence the exposure to spores inside home is an important factor of sensitization. The aim of this study was to determine the distribution and prevalence of species of Alternaria, Aspergillus, Cladosporium and Penicillium inside and outside of homes of patients allergic to fungi and to evaluate seasonal variations. Methods:

  14. The appearance of iprodione resistance in Alternaria alternata , the cause of brown spot of Murcott tangor

    Microsoft Academic Search

    D. G. Hutton

    1989-01-01

    Iprodione has established a reputation in recent years for controlling diseases caused by Alternaria spp. It is registered in Queensland for control of tar­ get spot of tomato (Lycopersicon esculentum Mill.) caused by A. solani Sorauer, alternata spot of passionfruit (Fragaria x enenesse Duchesne) caused by A. elternete (Fr.) Keissler and brown spot of Mur­ cott tangor (Citrus sinensis (L.)

  15. Reclassification of the butternut canker fungus, Sirococcus clavigignenti-juglandacearum, into the genus Ophiognomonia.

    PubMed

    Broders, K D; Boland, G J

    2011-01-01

    Sirococcus clavigignenti-juglandacearum (Sc-j), which causes a canker disease on butternut, is largely responsible for the decline of this tree in the United States and Canada. The original description of the species was based on anamorphic characters because the teleomorph is unknown. Recent phylogenetic investigations have found that Sc-j is not a member of the genus Sirococcus, and accurate taxonomic classification is required. The objective of this study is to use sequence data to determine the phylogenetic placement of Sc-j within the Gnomoniaceae, Diaporthales. Isolates were recovered from infected Juglans ailantifolia var. cordiformis (heartnut), Juglans cinerea (butternut), and Juglans nigra (black walnut) in Ontario and the eastern United States. The genes coding for ?-tubulin, actin, calmodulin, internal transcribed spacers 1 and 2, and the translation elongation factor 1-alpha from 28 isolates of Sc-j and representatives of the major lineages within the Gnomoniaceae were evaluated. There was no difference in the sequences of the five genes among the isolates of Sc-j studied, indicating a recent introduction followed by asexual reproduction and spread via conidia. The phylogenetic analyses demonstrate this fungus does not belong to the genus Sirococcus, and provides strong support (99% MP and 100% NJ bootstrap values, and 100% Bayesian posterior probabilities) for its inclusion in the genus Ophiognomonia, thereby supporting a reclassification of the butternut canker fungus to Ophiognomonia clavigignenti-juglandacearum. PMID:21215957

  16. Effect of the duration of inoculum exposure on development of citrus canker symptoms on seedlings of Swingle citrumelo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is one of the most serious diseases citrus in Florida, and elsewhere in the world. The disease causes yield loss and some fresh fruit trade restrictions may apply. Cultural management techniques such as windbreaks may work by not only reducing wind...

  17. Under severe HLB and citrus canker pressure, 'Triumph' and 'Jackson' perform better than 'Flame' and 'Marsh' grapefruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Canker (CC) threaten the viability of Florida grapefruit production. ‘Triumph’ (T), reportedly a grapefruit/sweet orange hybrid, is similar to seedy white grapefruit with earlier maturity and lower bitterness. ‘Jackson’ (J) is a low-seeded budsport of ‘Triumph’. Tree h...

  18. Under severe citrus canker and HLB (Huanglongbing) pressure, Triumph and Jackson perform better than Flame and Marsh grapefruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Canker (CC) threaten the viability of Florida grapefruit production. Triumph (T), reportedly a grapefruit/sweet orange hybrid, is similar to seedy white grapefruit with earlier maturity and lower bitterness. Jackson (J) is a low-seeded budsport of Triumph. Tree health ...

  19. Effect of alternative strategies for the disinfection of tomato seed infected with bacterial canker ( Clavibacter michiganensis subsp. michiganensis)

    Microsoft Academic Search

    A.-M. Kasselaki; D. Goumas; L. Tamm; J. Fuchs; J. Cooper; C. Leifert

    2011-01-01

    Currently there is a lack of effective seed treatments for bacterial pathogens, with Cu-based compounds (the only chemical treatments permitted under organic farming standards) only providing partial control. The aim of this study was to quantify the effect of alternative treatments for the control of bacterial canker (Clavibacter michiganensis subsp. michiganensis), a major seed-borne bacterial disease in tomato. Treatments assessed

  20. Selection of Antagonistic Bacteria of Clavibacter michiganensis subsp. michiganensis and Evaluation of Their Efficiency Against Bacterial Canker of Tomato

    Microsoft Academic Search

    E. H. Boudyach; M. Fatmi; O. Akhayat; E. Benizri; A. Ait Ben Aoumar

    2001-01-01

    A 178 bacterial strains, antagonistic towards Clavibacter michiganensis subsp. michiganensis , the causal agent of bacterial canker of tomato, were isolated from bulk soil, the rhizosphere and rhizoplane of tomato, originating from different sites in the Souss-Massa Valley, Agadir, Morocco. The strains were characterized on the basis of the Gram stain, sporulation, fluorescence on King's B medium and physiological tests.

  1. Occurrence of bacterial canker in tomato fields of Karnataka and effect of biological seed treatment on disease incidence

    Microsoft Academic Search

    S. Umesha

    2006-01-01

    Bacterial canker caused by Clavibacter michiganensis ssp. michiganensis was detected during a survey of tomato fields in the state of Karnataka, India. The disease incidence ranged from 25% to 48%. The pathogen was isolated from infected plant material and seeds. The pathogen was also detected in tomato seeds by laboratory assay and its identity was confirmed by biochemical, physiological, hypersensitivity

  2. Incidence and severity of Asiatic citrus canker on citrus and citrus–related germplasm in a Florida field planting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri ssp. citri (Hasse), is the causal agent of Asiatic citrus canker (ACC), a commercially important disease in Florida citrus, as well as in many other regions. In this study we evaluated occurrence of foliar lesions from ACC on progenies of 94 seed-source genotypes (hereafter called ...

  3. Fusarium circinatum and pitch canker of Pinus in Colombia E. T. Steenkamp & C. A. Rodas & M. Kvas &

    E-print Network

    Fusarium circinatum and pitch canker of Pinus in Colombia E. T. Steenkamp & C. A. Rodas & M. Kvas 2005­2007, symptoms typical of those associated with F. circinatum were observed in Colombia on nursery species commonly grown in Colombia. By making use of morphology and DNA-based methods, as well

  4. Artificial neural network models of relationships between Alternaria spores and meteorological factors in Szczecin (Poland)

    NASA Astrophysics Data System (ADS)

    Grinn-Gofro?, Agnieszka; Strzelczak, Agnieszka

    2008-11-01

    Alternaria is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we constructed predictive models for the fungal spore circulation in Szczecin, Poland. Monthly forecasting models were developed for the airborne spore concentrations of Alternaria, which is one of the most abundant fungal taxa in the area. Aerobiological sampling was conducted over 2004-2007, using a Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation; maximum and average wind speed; relative humidity; and maximum, minimum, average, and dew point temperature. The original factors as well as with lags (up to 3 days) were used as the explaining variables. Due to non-linearity and non-normality of the data set, the modelling technique applied was the artificial neural network (ANN) method. The final model was a split model with classification (spore presence or absence) followed by regression for spore seasons and log(x+1) transformed Alternaria spore concentration. All variables except maximum wind speed and precipitation were important factors in the overall classification model. In the regression model for spore seasons, close relationships were noted between Alternaria spore concentration and average and maximum temperature (on the same day and 3 days previously), humidity (with lag 1) and maximum wind speed 2 days previously. The most important variable was humidity recorded on the same day. Our study illustrates a novel approach to modelling of time series with short spore seasons, and indicates that the ANN method provides the possibility of forecasting Alternaria spore concentration with high accuracy.

  5. Analysis of the isothiocyanates present in cabbage leaves extract and their potential application to control Alternaria rot in bell peppers

    Microsoft Academic Search

    R. Troncoso; C. Espinoza; A. Sánchez-Estrada; M. E. Tiznado; Hugo S. García

    2005-01-01

    The potential use of cabbage isothiocyanates to control Alternaria rot in bell pepper was tested. Solid phase microextraction and gas chromatography–mass spectrometry found allyl, benzyl, 2-phenylethyl and phenyl isothiocyanates in a ratio of 1:3.5:5.3:9.6, respectively, in cabbage leaves. The same proportion was used to prepare an isothiocyanate mixture from reagent grade isothiocyanates (MCIT) to test the effect on Alternaria alternata

  6. Temperature, humidity, wounding and leaf age influence the development of Alternaria alternata lesions on leaves of Paulownia fortunei

    Microsoft Academic Search

    C. E. Pleysier; K. L. Bayliss; G. E. St. J. Hardy

    2006-01-01

    Alternaria blight, caused by Alternaria alternata, is a recent and serious disease of commercially grown Paulownia trees in Western Australia. This study investigated the\\u000a effect of temperature, humidity, wounding and leaf age on lesion development. Temperature had a significant effect on infection,\\u000a with lesion development and expansion observed to increase from 15–25°C, declining between 30 and 37°C. Relative humidity\\u000a (RH)

  7. Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

    PubMed Central

    2010-01-01

    Background Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control. PMID:20388224

  8. Development of a polymerase chain reaction-based assay for the detection of Alternaria fungal contamination in food products.

    PubMed

    Zur, G; Hallerman, E M; Sharf, R; Kashi, Y

    1999-10-01

    Alternaria sp. are important fungal contaminants of vegetable, fruit, and grain products, including Alternaria alternata, a contaminant of tomato products. To date, the Howard method, based on microscopic observation of fungal filaments, has been the standard examination for inspection of tomato products. We report development of a polymerase chain reaction (PCR)-based method for detection of Alternaria DNA. PCR primers were designed to anneal to the internal transcribed regions ITS1 and ITS2 of the 5.8S rRNA gene of Alternaria but not to other microbial or tomato DNA. We demonstrate use of the PCR assay to detect Alternaria DNA in experimentally infested and commercially obtained tomato sauce and tomato powder. Use of the PCR method offers a rapid and sensitive assay for the presence of Alternaria DNA in tomato products. The apparent breakdown of DNA in tomato sauce may limit the utility of the assay to freshly prepared products. The assay for tomato powder is not affected by storage time. PMID:10528725

  9. Genome sequence of a novel endornavirus from the phytopathogenic fungus Alternaria brassicicola.

    PubMed

    Shang, Hong-Hong; Zhong, Jie; Zhang, Ru-Jia; Chen, Chuan-Yuan; Gao, Bi-Da; Zhu, Hong-Jian

    2015-07-01

    In an effort to discover new mycoviruses from phytopathogenic fungi, a dsRNA molecule of 10,290 nt, resembling those associated with the viruses belonging to the family Endornaviridae, was isolated from Alternaria brassicicola, one of the causal agents of rapeseed black spot disease. Genome analysis revealed the presence of a single open reading frame coding for a polyprotein of 3400 aa containing conserved viral methyltransferase (MTR), viral RNA helicase 1 (Hel-1), and RNA-dependent RNA polymerase (RdRp) domains. In addition, a cysteine-rich region (CRR) with conserved CXCC motifs, shared among several endornaviruses, was also identified between the MTR and Hel-1 domains. Phylogenetic analysis based on the RdRp sequence strongly suggested that the virus infecting A. brassicicola should be considered a representative of a novel endornavirus species, and this virus was designated as Alternaria brassicicola endornavirus 1 (AbEV1). PMID:25951967

  10. Adaptive Potential of Maritime Pine (Pinus pinaster) Populations to the Emerging Pitch Canker Pathogen, Fusarium circinatum

    PubMed Central

    Elvira-Recuenco, Margarita; Iturritxa, Eugenia; Majada, Juan; Alia, Ricardo; Raposo, Rosa

    2014-01-01

    There is a concern on how emerging pests and diseases will affect the distribution range and adaptability of their host species, especially due to different conditions derived from climate change and growing globalization. Fusarium circinatum, which causes pitch canker disease in Pinus species, is an exotic pathogen of recent introduction in Spain that threatens its maritime pine (P. pinaster) stands. To predict the impact this disease will have on the species, we examine host resistance traits and their genetic architecture. Resistance phenotyping was done in a clonal provenance/progeny trial, using three-year-old cuttings artificially inoculated with the pathogen and maintained under controlled environmental conditions. A total number of 670 ramets were assessed, distributed in 10 populations, with a total of 47 families, 2 to 5 half-sibs per family, and 3–7 ramets per clone. High genetic variation was found at the three hierarchical levels studied: population, family and clone, being both additive and non-additive effects important. Narrow-sense and broad-sense heritability estimates were relatively high, with respective values of 0.43–0.58 and 0.51–0.8, depending on the resistance traits measured (lesion length, lesion length rate, time to wilting, and survival). These values suggest the species' high capacity of evolutionary response to the F. circinatum pathogen. A population originated in Northern Spain was the most resistant, while another from Morocco was the most susceptible. The total number of plants that did not show lesion development or presented a small lesion (length<30 mm) was 224 out of 670, indicating a high proportion of resistant trees in the offspring within the analyzed populations. We found large differences among populations and considerable genetic variation within populations, which should allow, through natural or artificial selection, the successful adaptation of maritime pine to pitch canker disease. PMID:25500822

  11. Detection of Alternaria radicina and A. dauci from imported carrot seed in New Zealand

    Microsoft Academic Search

    J. J. Soteros

    1979-01-01

    Seven laboratory methods and a glasshouse test used to determine the incidence of two seed-borne pathogens, Alternaria radicina and A. dauci, are compared and discussed. Incidence ranged from 0–26% and 0–1%, respectively. The two most efficient methods of detection were a heat treatment and the Copenhagen germinator test. The heat treatment was the only method that detected internal infections of

  12. Maculosin, a Host-Specific Phytotoxin for Spotted Knapweed from Alternaria alternata

    Microsoft Academic Search

    Andrea C. Stierle; John H. Cardellina; Gary A. Strobel

    1988-01-01

    Several diketopiperazines have been isolated from liquid cultures of Alternaria alternata, the causal agent of black leaf blight of spotted knapweed, Centaurea maculosa Lam. One of these compounds, maculosin [the diketopiperazine cyclo-(-L-Pro-L-Tyr-)], was active in the nicked-leaf bioassay at 10-5 M; synthetic maculosin possessed chemical and biological activities identical to those of the natural product. Other diketopiperazines isolated from the

  13. Relationship between Fusarium graminearum and Alternaria alternata contamination and deoxynivalenol occurrence on Argentinian durum wheat

    Microsoft Academic Search

    H. H. L. González; E. J. Mart; A. Pacin; S. L. Resnik; Cient ´ ificas

    1998-01-01

    A mycological survey was carried out on durum wheat (Triticum durum) samples from the main production area of Argentina. The\\u000a isolation frequency and relative density of species of dematiaceous fungi, and genus Fusarium were calculated. Alternaria\\u000a alternata and Fusarium graminearum were the predominant fungal species. An analysis of deoxynivalenol (DON) natural contamination\\u000a was also performed on a limited number of

  14. Interaction between Alternaria alternata or Fusarium equiseti and Glomus mosseae and its effects on plant growth

    Microsoft Academic Search

    C. B. McAllister; J. M. Garcia-Garrido; I. Garcia-Romera; A. Godeas; J. A. Ocampo

    1997-01-01

    The effect of inoculation with the saprophytic fungi Alternaria alternata or Fusarium equiseti on maize (Zea mays) and lettuce (Lactuca sativa) with or without arbuscular mycorrhizal (AM) colonization by Glomus mosseae was studied in a greenhouse trial. Plant dry weights of non-AM-inoculated maize and lettuce were unaffected by the presence\\u000a of A. alternata and F. equiseti. In contrast, A. alternata

  15. A technique for screening muskmelon seedlings for resistance to Alternaria cucumerina 

    E-print Network

    Carmody, Beth Elaine

    1983-01-01

    and type were recorded on each plant 5 days after inoculation. Optimum inoculum concentration, temperature and leafwetness treatment for infection was 5500 conidia/ml, 21C and 18 hrs leafwetness for the cotyledon studies. The optimum conditiot;s... seedlings with a spray atomizer delivering approx. 0. 2 ml of inoculum per plant. . . . , . . . . . . . . . . 10 Figure 3. (A) Typical lesion type on cotyledons of 5 muskmelon cultivars 5 days after inoculation with Alternaria cucumerina (5500 conidia...

  16. Arabidopsis cell death in compatible and incompatible interactions with Alternaria brassicicola

    Microsoft Academic Search

    Mukhamad Su’udi; Min Gab Kim; Sang-Ryeol Park; Duk-Ju Hwang; Shin-Chul Bae; Il-Pyung Ahn

    2011-01-01

    Two strains of necrotrophic Alternaria brassicicola, Ab40857 and Ab42464, are virulent on Korean cabbage and several wild types of Arabidopsis thaliana. Interaction between Ab42464 and Col-0 was compatible, whereas interaction between Ab40857 and Col-0 was incompatible. The\\u000a loss of defense, no death (dnd) 1 function abrogated the compatibility between Ab42464 and Col-0, and the accelerated cell death (acd) 2 mutation

  17. Role of micronutrients in defense to white rust and Alternaria blight infecting Indian mustard.

    PubMed

    Rathi, A S; Singh, Dhiraj; Avtar, Ram; Kumar, Pawan

    2015-03-01

    Field experiments were carried out at Oilseeds Research Area of CCS Haryana Agricultural University, Hisar during rabi, 2008-09 to 2011-12 to find out the possible role of soil application of different micronutrients alone and in combinations in defense to white rust and Alternaria blight diseases in Indian mustard [Brassica juncea (L.) Czern & Coss.]. Among the sole application of micronutrients, minimum disease severity of both white rust (35.0%) and Alternaria blight (31.8%) was observed when S @ 40 kg ha in the form of Gypsum was applied as basal dose in the soil. When Gypsum was supplemented with Borax @10 kg ha(-1) or with ZnSO4 @15 kg ha(-1) the level of tolerance seems to be improved for both the diseases as compared to the sole treatment of each nutrient, i.e., ZnSO4 @ 15 kg/ha, Borax @ 10 kg ha' and Gypsum @ 250 kg ha(-1). Furthermore, minimum disease severity of both white rust (31.3 %) and Alternaria blight (26.3 %) was observed with soil application of ZnSO4 @ 15 kg ha(-1) + Borax @ 10 kg ha(-1) + Gypsum @250 kg ha(-1) as basal dose as compared to the severity of white rust (43.6%) and Alternaria blight (38.6%) in untreated check. Significant increase in seed yield (1612 kg ha(-1)) was also recorded in above mentioned treatment as compared to the yield (1337 kg ha(-1)) in untreated check. These findings will also be helpful in maintaining soil health and minimizing the losses due to both the fungal diseases for eco-friendly sustainability of Indian mustard. PMID:25895272

  18. Crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen

    NASA Astrophysics Data System (ADS)

    Skjøth, C. A.; Sommer, J.; Frederiksen, L.; Gosewinkel Karlson, U.

    2012-06-01

    This study tests the hypothesis that Danish agricultural areas are the main source to airborne Alternaria spores in Copenhagen, Denmark. We suggest that the source to the overall load is mainly local, but with intermittent Long Distance Transport (LDT) from more remote agricultural areas. This hypothesis is supported by investigating a 10 yr bi-hourly record of Alternaria spores in the air from Copenhagen. This record shows 232 clinically relevant episodes with a distinct daily profile. The data analysis also revealed potential LDT episodes almost every year. A source map and analysis of atmospheric transport suggest that LDT always originates from the main agricultural areas in Central Europe. A dedicated emission study in cereal crops under harvest during 2010 also supports our hypothesis. The emission study showed that although the fields had been treated against fungal infections, harvesting still produced large amounts of airborne fungal spores. It is likely that such harvesting periods can cause clinically relevant levels of fungal spores in the atmosphere. Our findings suggest that crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen as well as other urban areas in this region. It is likely that such episodes could be simulated using atmospheric transport models.

  19. Citrus Black Rot is Caused by Phylogenetically Distinct Lineages of Alternaria alternata.

    PubMed

    Peever, T L; Carpenter-Boggs, L; Timmer, L W; Carris, L M; Bhatia, A

    2005-05-01

    ABSTRACT Phylogenetic analysis revealed that isolates of Alternaria alternata causing black rot of citrus were associated with six well-supported evolutionary lineages. Isolates recovered from brown spot lesions on Minneola tangelo, leaf spot lesions on rough lemon, and healthy citrus tissue and noncitrus hosts were related closely to isolates from black-rotted fruit. Phylogenies estimated independently from DNA sequence data from an endopolygalacturonase gene (endoPG) and two anonymous regions of the genome (OPA1-3 and OPA2-1) had similar topologies, and phylogenetic analysis was performed on the combined data set. In the combined phylogeny, isolates from diverse ecological niches on citrus and noncitrus hosts were distributed in eight clades. Isolates from all lineages, regardless of ecological or host association, caused black rot in fruit inoculation assays, demonstrating that small-spored Alternaria isolates associated with different ecological niches on citrus and other plant hosts are potential black rot pathogens. These data also indicated that the fungi associated with black-rotted fruit do not form a natural evolutionary group distinct from other Alternaria pathogens and saprophytes associated with citrus. The use of the name A. citri to describe fungi associated with citrus black rot is not justified and it is proposed that citrus black rot fungi be referred to as A. alternata. PMID:18943316

  20. TPCP: Pitch canker PITCH CANKER

    E-print Network

    to commercial forestry in South Africa today. In the past seven years, Fusarium subglutinans f.sp. pini or FSP successful control. Insects such as Ips spp., Pityophthorus spp., Pissodes sp. and Conophthorus spp. have

  1. Association of IL4RA single nucleotide polymorphisms, HLA-DR and HLA-DQ in children with Alternaria-sensitive moderate-severe asthma

    Microsoft Academic Search

    Alan P Knutsen; Hari M Vijay; Barbara Kariuki; Luis A Santiago; Ralph Graff; Jonathan D Wofford; Maulik R Shah

    2010-01-01

    BACKGROUND: Asthma afflicts 6% to 8% of the United States population, and severe asthma represents approximately 10% of asthmatic patients. Several epidemiologic studies in the United States and Europe have linked Alternaria sensitivity to both persistence and severity of asthma. In order to begin to understand genetic risk factors underlying Alternaria sensitivity and asthma, in these studies we examined T

  2. Genetic Differentiation and Host Specificity Among Populations of Alternaria spp. Causing Brown Spot of Grapefruit and Tangerine ? Grapefruit Hybrids in Florida

    Microsoft Academic Search

    T. L. Peever; L. Olsen; A. Ibañez; L. W. Timmer

    2000-01-01

    Peever, T. L., Olsen, L., Ibañez, A., and Timmer, L. W. 2000. Genetic differentiation and host specificity among populations of Alternaria spp. causing brown spot of grapefruit and tangerine ? grapefruit hybrids in Florida. Phytopathology 90:407-414. Alternaria spp. were sampled from brown spot lesions in several geo- graphically separated citrus groves and different grapefruit and tangerine ? grapefruit hybrid cultivars

  3. Mycotoxin production in liquid culture and on plants infected with Alternaria spp. isolated from rocket and cabbage.

    PubMed

    Siciliano, Ilenia; Ortu, Giuseppe; Gilardi, Giovanna; Gullino, Maria Lodovica; Garibaldi, Angelo

    2015-03-01

    Fungi belonging to the genus Alternaria are common pathogens of fruit and vegetables with some species able to produce secondary metabolites dangerous to human health. Twenty-eight Alternaria isolates from rocket and cabbage were investigated for their mycotoxin production. Five different Alternaria toxins were extracted from synthetic liquid media and from plant material (cabbage, cultivated rocket, cauliflower). A modified Czapek-Dox medium was used for the in vitro assay. Under these conditions, more than 80% of the isolates showed the ability to produce at least one mycotoxin, generally with higher levels for tenuazonic acid. However, the same isolates analyzed in vivo seemed to lose their ability to produce tenuazonic acid. For the other mycotoxins; alternariol, alternariol monomethyl ether, altenuene and tentoxin a good correlation between in vitro and in vivo production was observed. In vitro assay is a useful tool to predict the possible mycotoxin contamination under field and greenhouse conditions. PMID:25751147

  4. Mycotoxin Production in Liquid Culture and on Plants Infected with Alternaria spp. Isolated from Rocket and Cabbage

    PubMed Central

    Siciliano, Ilenia; Ortu, Giuseppe; Gilardi, Giovanna; Gullino, Maria Lodovica; Garibaldi, Angelo

    2015-01-01

    Fungi belonging to the genus Alternaria are common pathogens of fruit and vegetables with some species able to produce secondary metabolites dangerous to human health. Twenty-eight Alternaria isolates from rocket and cabbage were investigated for their mycotoxin production. Five different Alternaria toxins were extracted from synthetic liquid media and from plant material (cabbage, cultivated rocket, cauliflower). A modified Czapek-Dox medium was used for the in vitro assay. Under these conditions, more than 80% of the isolates showed the ability to produce at least one mycotoxin, generally with higher levels for tenuazonic acid. However, the same isolates analyzed in vivo seemed to lose their ability to produce tenuazonic acid. For the other mycotoxins; alternariol, alternariol monomethyl ether, altenuene and tentoxin a good correlation between in vitro and in vivo production was observed. In vitro assay is a useful tool to predict the possible mycotoxin contamination under field and greenhouse conditions. PMID:25751147

  5. A polyphasic approach for the characterization of endophytic Alternaria strains isolated from grapevines.

    PubMed

    Polizzotto, Rachele; Andersen, Birgitte; Martini, Marta; Grisan, Simone; Assante, Gemma; Musetti, Rita

    2012-01-01

    A polyphasic approach was set up and applied to characterize 20 fungal endophytes belonging to the genus Alternaria, recovered from grapevine in different Italian regions. Morphological, microscopical, molecular and chemical investigations were performed and the obtained results were combined in a pooled cluster analysis. Following morphological analyses, all strains were grouped according to their three-dimensional sporulation pattern on PCA and to the colony characteristics on different substrates. After DNA extraction, all strains were analyzed by RAPD-PCR and the resulting profiles were subjected to cluster analysis. The metabolites extracted from the 20 Alternaria endophytes were analyzed by a HPLC and the resulting metabolite profiles were subjected to multivariate statistic analyses. In comparison with reference 'small-spored' Alternaria species, the 20 strains were segregated into two morphological groups: one belonging to the A. arborescens species-group and a second to the A. tenuissima species-group. RAPD analysis also showed that grapevine endophytes belonged to either the A. arborescens or the A. tenuissima species-group and that they were molecularly distinct from strains belonging to A. alternata. Chemotaxonomy gave the same grouping: the grapevine endophytic strains belong to A. arborescens or A. tenuissima species-groups producing known metabolites typical of these species-groups. Interestingly, the 20 grapevine endophytes were able to produce also a number of unknown metabolites, whose characterization could be useful for a more precise segregation of the two species-groups. The results show how complementary morphological, molecular and chemical data can clarify relationships among endophyte species-groups of low morphological divergence. PMID:22123507

  6. Alternaria alternata allergen, Alt a 1 - a unique, ?-barrel protein dimer exclusively found in fungi

    PubMed Central

    Chruszcz, Maksymilian; Chapman, Martin D.; Osinski, Tomasz; Solberg, Robert; Demas, Matthew; Porebski, Przemyslaw J.; Majorek, Karolina A.; Pomés, Anna; Minor, Wladek

    2012-01-01

    Background Alternaria is one of the most common molds associated with allergic diseases and 80% of Alternaria-sensitive patients produce IgE antibodies to a major protein allergen, Alt a 1. The structure and function of Alt a 1 is unknown. Objective To obtain a high resolution structure of Alt a 1 by X-ray crystallography and to investigate structural relationships between Alt a 1 and other allergens and proteins reported in the Protein Data Bank. Methods X-ray crystallography was used to determine the structure of Alt a 1 using a custom-designed set of crystallization conditions. An initial Alt a 1 model was determined by the application of a Ta6Br122+ cluster and Single-wavelength Anomalous Diffraction. Bioinformatic analyses were used to compare the Alt a 1 sequence and structure with other proteins. Results Alt a 1 is a unique ?-barrel comprising 11 ?-strands and forms a ‘butterfly-like’ dimer linked by a single disulfide bond, with a large (1345Å2) dimer interface. Intramolecular disulfide bonds are conserved among Alt a 1 homologs. Currently, the Alt a 1 structure has no equivalent in the Protein Data Bank. Bioinformatics analyses suggest that the structure is found exclusively in fungi. Four previously reported putative IgE binding peptides have been located on the Alt a 1 structure. Conclusions Alt a 1 has a unique, dimeric ?-barrel structure that appears to define a new protein family with unknown function found exclusively in fungi. The location of IgE antibody binding epitopes is in agreement with the structural analysis of Alt a 1.The Alt a 1 structure will allow mechanistic structure/function studies and immunologic studies directed towards new forms of immunotherapy for Alternaria-sensitive allergic patients. PMID:22664167

  7. Signatures of recombination in clonal lineages of the citrus brown spot pathogen, Alternaria alternata sensu lato.

    PubMed

    Stewart, Jane E; Thomas, Kalyn A; Lawrence, Christopher B; Dang, Ha; Pryor, Barry M; Timmer, L M Pete; Peever, Tobin L

    2013-07-01

    Most Alternaria spp. are considered asexual but recent molecular evolution analyses of Alternaria mating-type genes show that the mating locus is under strong purifying selection, indicating a possible role in sexual reproduction. The objective of this study was to determine the mode of reproduction of an Alternaria alternata sensu lato population causing citrus brown spot in central Florida. Mating type of each isolate was determined, and isolates were sequenced at six putatively unlinked loci. Three genetically distinct subpopulations (SH1, SH4A, and SH4B) were identified using network and Bayesian population structure analyses. Results demonstrate that most subpopulations of A. alternata associated with citrus are clonal but some have the ability to extensively recombine through a cryptic sexual cycle or parasexual cycle. Although isolates were sampled in close physical proximity (?2,500-m² area), we were able to reject a random mating model using multilocus gametic disequilibrium tests for two subpopulations, SH1 and SH4B, suggesting that these subpopulations were predominantly asexual. However, three recombination events were identified in SH1 and SH4B and localized to individuals of opposite mating type, possibly indicating meiotic recombination. In contrast, in the third subpopulation (SH4A), where only one mating type was present, extensive reticulation was evident in network analyses, and multilocus gametic disequilibrium tests were consistent with recombination. Recombination among isolates of the same mating type suggests that a nonmeiotic mechanism of recombination such as the parasexual cycle may be operating in this subpopulation. The level of gene flow detected among subpopulations does not appear to be sufficient to prevent differentiation, and perhaps future speciation, of these A. alternata subpopulations. PMID:23441968

  8. First Report of Black Spot Disease Caused by Alternaria alternata on Sweet Persimmon Fruits.

    PubMed

    Lee, Jung Han; Kim, Jinwoo; Kwak, Youn-Sig

    2013-09-01

    Black spot of sweet persimmon, caused by Alternaria alternata, occurred in an orchard in Gyeongnam province, Korea in 2012. The symptom was appearance of 0.5 to 4 cm black spots on the surface of fruit. The pathogen was isolated from flesh of disease lesions. The causal agent was identified as A. alternata by morphological characteristics and sequencers of the internal transcribed spacer (ITS) 1 and ITS4 regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of A. alternata. PMID:24198674

  9. Two new macrosporin dimers from the fungus Alternaria sp. XZSBG-1.

    PubMed

    Chen, Bin; Liu, Lan; Zhu, Xun; Wang, Jun; Long, Yi; Jiang, Si-Ping; Xu, Ai-Guo; Lin, Yong-Cheng

    2015-07-01

    Two new macrosporin dimers (1-2) along with four known compounds (3-6) were isolated from the extracts of the fungal strain Alternaria sp. XZSBG-1 from the sediment of the salt lake in the Bange, Tibetan, China. Their structures were determined by spectroscopic methods, mainly by 2D NMR spectra. Compounds 1 and 2 are new macrosporin dimers with symmetric chemical structures. In the cytotoxicity assay and inhibited alpha-glucosidase activity assay, all these compounds showed no notable inhibitory activity. PMID:25573432

  10. Dead flower buds of pear: effect of tree growth control, and Alternaria alternata as causal agent.

    PubMed

    Wenneker, M; Heijne, B; Tjou-Tam-Sin, L T; Van Bruggen, A S; Vink, P

    2004-01-01

    Dead (dormant) flower buds of pear is an important phenomenon in pear production in the Netherlands. Vigourous or unbalanced tree growth and Pseudomonas syringae pv. syringae are mentioned as likely causes of dead flower buds. Several tree growth control treatments including ethephon. Regalis (Prohexadione-Ca) and root pruning were evaluated. Regalis increased disease incidence. The plant stimulant (foliar fertilizer) Resistim (potassium phosphonate) reduced disease incidence. Pseudomonas syringae pv. syringae was occasionally isolated from diseased flower buds. However, Alternaria alternata was nearly always isolated from diseased buds. Indicating a strong relation between this fungus and dead flower buds of pear. PMID:15756820

  11. Maculosin, a host-specific phytotoxin for spotted knapweed from Alternaria alternata.

    PubMed

    Stierle, A C; Cardellina, J H; Strobel, G A

    1988-11-01

    Several diketopiperazines have been isolated from liquid cultures of Alternaria alternata, the causal agent of black leaf blight of spotted knapweed, Centaurea maculosa Lam. One of these compounds, maculosin [the diketopiperazine cyclo(-L-Pro-L-Tyr-)], was active in the nicked-leaf bioassay at 10(-5) M; synthetic maculosin possessed chemical and biological activities identical to those of the natural product. Other diketopiperazines isolated from the fungus possessed either less activity or none at all. In tests against 19 plant species, maculosin was phytotoxic only to spotted knapweed. Thus maculosin is a host-specific phytotoxin from a weed pathogen. PMID:16593989

  12. Maculosin, a host-specific phytotoxin for spotted knapweed from Alternaria alternata

    PubMed Central

    Stierle, Andrea C.; Cardellina, John H.; Strobel, Gary A.

    1988-01-01

    Several diketopiperazines have been isolated from liquid cultures of Alternaria alternata, the causal agent of black leaf blight of spotted knapweed, Centaurea maculosa Lam. One of these compounds, maculosin [the diketopiperazine cyclo(-L-Pro-L-Tyr-)], was active in the nicked-leaf bioassay at 10-5 M; synthetic maculosin possessed chemical and biological activities identical to those of the natural product. Other diketopiperazines isolated from the fungus possessed either less activity or none at all. In tests against 19 plant species, maculosin was phytotoxic only to spotted knapweed. Thus maculosin is a host-specific phytotoxin from a weed pathogen. PMID:16593989

  13. Population structure of the butternut canker fungus, Ophiognomonia clavigignenti-juglandacearum, in North American forests.

    PubMed

    Broders, K D; Boraks, A; Sanchez, A M; Boland, G J

    2012-09-01

    The occurrence of multiple introduction events, or sudden emergence from a host jump, of forest pathogens may be an important factor in successful establishment in a novel environment or on a new host; however, few studies have focused on the introduction and emergence of fungal pathogens in forest ecosystems. While Ophiognomonia clavigignenti-juglandacearum (Oc-j), the butternut canker fungus, has caused range-wide mortality of butternut trees in North America since its first observation in 1967, the history of its emergence and spread across the United States and Canada remains unresolved. Using 17 single nucleotide polymorphic loci, we investigated the genetic population structure of 101 isolates of Oc-j from across North America. Clustering analysis revealed that the Oc-j population in North America is made up of three differentiated genetic clusters of isolates, and these genetic clusters were found to have a strong clonal structure. These results, in combination with the geographic distribution of the populations, suggest that Oc-j was introduced or has emerged in North America on more than one occasion, and these clonal lineages have since proliferated across much of the range of butternut. No evidence of genetic recombination was observed in the linkage analysis, and conservation of the distinct genetic clusters in regions where isolates from two or more genetic clusters are present, would indicate a very minimal or non-existent role of sexual recombination in populations of Oc-j in North America. PMID:23139872

  14. Summer heat and low soil organic matter influence severity of hazelnut Cytospora canker.

    PubMed

    Lamichhane, Jay Ram; Fabi, Alfredo; Varvaro, Leonardo

    2014-04-01

    Cytospora canker, caused by the fungus Cytospora corylicola, is present in hazelnut production areas worldwide. The disease is widespread throughout the main production areas of Italy. The causal agent is considered to be a secondary invader of damaged tissue that attacks mainly stressed plants. However, little is known of disease severity and stress factors that predispose plants to infection. In particular, the role of pedoclimatic factors was investigated. Direct survey indicated that disease severity varied across several study sites. Geostatistics showed a strong positive correlation between disease severity index and summer heat (r = 0.80 and 0.91 for July and August, respectively) and strong negative correlation between disease severity index and soil organic matter (r = -0.78). A moderate positive correlation between disease severity index and magnesium/potassium ratio (r = 0.58) and moderate negative correlations between disease severity index and total soil nitrogen (r = -0.53), thermal shock (r = -0.46), and rainfall (r = -0.53) were determined. No significant correlation between disease severity index and soil aluminum (r = -0.35), soil pH (r = -0.01), and plant age (r = -0.38) was found. PMID:24168042

  15. The rare case of Alternaria alternata cutaneous and pulmonary infection in a heart transplant recipient treated by azole antifungals.

    PubMed

    Se?níková, Zuzana; J?zlová, Kate?ina; Vojá?ková, Nad?žda; Kazakov, Dmitry V; Hošková, Lenka; Fialová, Jorga; Džambová, Martina; Hercogová, Jana

    2014-01-01

    We report a case of Alternaria alternata cutaneous and pulmonary infection in a 62-year-old man after heart transplantation treated by azole antifungals. Alternaria spp. belong to a group of opportunistic dematiaceous fungi with worldwide distribution. The cutaneous form of the infection in human is very rare and occurs predominantly among immunosuppressed patients. Therefore, diagnosis is often delayed or not reached at all. Appropriate treatment is not standardized and remains a matter of discussion. According to current studies, the best results are obtained with systemic azole antifungal therapy combined with surgical intervention. PMID:24112410

  16. Effects of the nematicide 1,3-dichloropropene on weed populations and stem canker disease severity in potatoes

    Microsoft Academic Search

    Patrick P. J. Haydock; Thomas Deliopoulos; Ken Evans; Stephen T. Minnis

    2010-01-01

    The soil fumigant 1,3-dichloropropene (1,3-D) has been used in the UK for the control of potato cyst nematodes (PCN), Globodera pallida (Stone) and Globodera rostochiensis (Wollenweber), but its potential herbicidal activity has not been extensively investigated in this country. Field and glasshouse studies were therefore conducted to evaluate the potential of 1,3-D for the control of weeds in potatoes, and

  17. Effects of Compost and Biocontrol Amendments on Stem Canker, Black Scurf, and Common Scab of Potato, 2006

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two composts and two biological control agents were evaluated alone and in combination for their effects on the development of soilborne diseases of potato. The experiment was conducted on field research plots in Newport, ME. The compost amendments consisted of commercially available compost blends,...

  18. Inheritance of resistance to southern stem canker (Diaporthe phaseolorum f.s. meridionalis) in soybean [Glycine max (L.) Merr.] 

    E-print Network

    Ngeleka, Kadima

    1990-01-01

    (Table 5) showed that all sub-populations were consistent with a 3:1 ratio, except the sub-population 140-1 whose computed chi-square value of 4. 69 exceeded the tabular value of 3. 8. The chi- square value for additivity (X ~ = 5. 4) was computed... Sub-populations Res. Observed Sus. Res. Expected Sus. Value 140-1 140-2 140-3 140-4 140-5 74 74 37 37 32 13 28 13 16 11 65. 25 76. 50 37. 50 39. 75 32. 25 21. 75 4. 69 25. 50 0. 33 12. 50 0. 03 13. 25 0. 76 10. 75 0. 01...

  19. First report of anthracnose stem Canker of the invasive perennial weed Lepidium draba caused by Colletotrichum higginsianum in Europe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The exotic perennial Lepidium draba occurs as an invasive weed in dense stands in rangelands and disturbed areas in several states of the western U. S., and as an agricultural weed in the prairie provinces of Canada. To help determine strategies for biological control of the weed such as a potential...

  20. Characterization of a genotoxic impact compound in Alternaria alternata infested rice as Altertoxin II.

    PubMed

    Schwarz, Christoph; Tiessen, Christine; Kreutzer, Martin; Stark, Timo; Hofmann, Thomas; Marko, Doris

    2012-12-01

    Toxicity-guided fractionation was used to identify DNA strand breaking impact compounds in extracts obtained from rice heavily infested with the Alternaria alternata strains DSM 62006 and DSM 62010. The major genotoxic potential measured in the comet assay using human colon carcinoma cells (HT29) could be attributed to three unknown peaks, whereas the fractions containing alternariol, its monomethylether or tenuazonic acid showed no significant DNA damaging effects. According to (1)H and (13)C-NMR spectroscopy, one genotoxic impact compound was identified as Altertoxin II (ATXII). ATXII showed potent DNA damaging properties in HT29 cells with substantial induction of formamidopyrimidine DNA glycosylase (FPG)-sensitive sites. However, no effect was observed with respect to the cellular redox status, measured in the DCF assay and as total glutathione. The induction of apoptosis could be excluded as a potential reason for enhanced DNA damage. After 24 h of incubation with 1 ?M ATX II, a significant increase of cells in the G(0)/G(1) phase was observed together with an inhibition of cell proliferation in the sulforhodamine B assay. Taken together, ATX II was found to contribute substantially to the genotoxic effects of complex extracts obtained from Alternaria alternata infested rice. The results demonstrate the high genotoxic potency of ATX II in human cells, underlining the necessity for further studies on the occurrence in food and its relevance for food safety. PMID:23076116

  1. STEM Career

    NSDL National Science Digital Library

    There are many groups and organizations in the United States working to encourage young people to enter STEM-related careers, and this website represents one of those endeavors. The STEM Career website was created by Professor Rich Feller of Colorado State University to help encourage young people to select just such a career path. The website contains updates on STEM career possibilities, and basic answers to questions like "Why STEM?" and "Why STEM Centric Career Development?" Visitors should also scan through the "STEM Disciplines" area on the homepage, as it contains resources about the job outlook for related STEM disciplines, such as biochemical engineering and engineering managers. Moving on, the site also features news updates from Professor Feller and his colleagues on subjects that include the ways in which corporations are promoting STEM education and women in STEM.

  2. Identification of putative TAL effector targets of the citrus canker pathogens shows functional convergence underlying disease development and defense response

    PubMed Central

    2014-01-01

    Background Transcriptional activator-like (TAL) effectors, formerly known as the AvrBs3/PthA protein family, are DNA-binding effectors broadly found in Xanthomonas spp. that transactivate host genes upon injection via the bacterial type three-secretion system. Biologically relevant targets of TAL effectors, i.e. host genes whose induction is vital to establish a compatible interaction, have been reported for xanthomonads that colonize rice and pepper; however, citrus genes modulated by the TAL effectors PthA“s” and PthC“s” of the citrus canker bacteria Xanthomonas citri (Xc) and Xanthomonas aurantifolii pathotype C (XaC), respectively, are poorly characterized. Of particular interest, XaC causes canker disease in its host lemon (Citrus aurantifolia), but triggers a defense response in sweet orange. Results Based on, 1) the TAL effector-DNA binding code, 2) gene expression data of Xc and XaC-infiltrated sweet orange leaves, and 3) citrus hypocotyls transformed with PthA2, PthA4 or PthC1, we have identified a collection of Citrus sinensis genes potentially targeted by Xc and XaC TAL effectors. Our results suggest that similar with other strains of Xanthomonas TAL effectors, PthA2 and PthA4, and PthC1 to some extent, functionally converge. In particular, towards induction of genes involved in the auxin and gibberellin synthesis and response, cell division, and defense response. We also present evidence indicating that the TAL effectors act as transcriptional repressors and that the best scoring predicted DNA targets of PthA“s” and PthC“s” in citrus promoters predominantly overlap with or localize near to TATA boxes of core promoters, supporting the idea that TAL effectors interact with the host basal transcriptional machinery to recruit the RNA pol II and start transcription. Conclusions The identification of PthA“s” and PthC“s” targets, such as the LOB (LATERAL ORGAN BOUNDARY) and CCNBS genes that we report here, is key for the understanding of the canker symptoms development during host susceptibility, or the defenses of sweet orange against the canker bacteria. We have narrowed down candidate targets to a few, which pointed out the host metabolic pathways explored by the pathogens. PMID:24564253

  3. Identification of a Polyketide Synthase Required for Alternariol (AOH) and Alternariol9Methyl Ether (AME) Formation in Alternaria alternata

    Microsoft Academic Search

    Debjani Saha; Ramona Fetzner; Britta Burkhardt; Joachim Podlech; Manfred Metzler; Ha Dang; Christopher Lawrence; Reinhard Fischer

    2012-01-01

    Alternaria alternata produces more than 60 secondary metabolites, among which alternariol (AOH) and alternariol-9-methyl ether (AME) are important mycotoxins. Whereas the toxicology of these two polyketide-based compounds has been studied, nothing is known about the genetics of their biosynthesis. One of the postulated core enzymes in the biosynthesis of AOH and AME is polyketide synthase (PKS). In a draft genome

  4. First Report of a Leaf Spot Caused by Alternaria brassicae on the Invasive Weed Lepidium draba in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A second leaf spot disease on the perennial invasive weed white top, aka hoary cress, was found in a stand of white top in south central Montana. The plant pathogen causing the lesions was identified as the fungus Alternaria brassicae. It was isolated, purified grown on a V-8 agar growth medium and ...

  5. COLONIZATION BY FUSARIUM AND ALTERNARIA SPP. OF SORGHUM GRAIN OF NEAR ISOGENIC LINES VARYING IN PLANT COLOR AND PERICARP COLOR.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Colonization by Fusarium and Alternaria spp. of sorghum grain of near isogenic lines varying in plant color and pericarp color. Deanna L. Funnell and Jeffery F. Pedersen, Grain, Forage and Bioenergy Research, USDA-ARS; Departments of Plant Pathology (DLF) and Agronomy (JFP), University of Nebraska. ...

  6. Protectant activity of reduced concentration copper sprays against Alternaria brown spot on ‘Fortune’ mandarin fruit in Spain

    Microsoft Academic Search

    A. Vicent; J. Armengol; J. García-Jiménez

    2009-01-01

    Alternaria brown spot (ABS) of mandarins is a serious disease of fruit and foliage of citrus, causing defoliation, fruit drop and rind blemishes on susceptible cultivars. In Spain, the disease causes severe losses on the late-maturing cultivars for export of ‘Fortune’ and ‘Nova’. Several fungicide sprays are needed to protect susceptible organs during the critical infection periods through the growing

  7. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease

    PubMed Central

    Hu, Yang; Zhang, Junli; Jia, Hongge; Sosso, Davide; Li, Ting; Frommer, Wolf B.; Yang, Bing; White, Frank F.; Wang, Nian; Jones, Jeffrey B.

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccAw, induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations. PMID:24474801

  8. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    PubMed

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria. PMID:25403594

  9. Bayesian Analysis for Inference of an Emerging Epidemic: Citrus Canker in Urban Landscapes

    PubMed Central

    Neri, Franco M.; Cook, Alex R.; Gibson, Gavin J.; Gottwald, Tim R.; Gilligan, Christopher A.

    2014-01-01

    Outbreaks of infectious diseases require a rapid response from policy makers. The choice of an adequate level of response relies upon available knowledge of the spatial and temporal parameters governing pathogen spread, affecting, amongst others, the predicted severity of the epidemic. Yet, when a new pathogen is introduced into an alien environment, such information is often lacking or of no use, and epidemiological parameters must be estimated from the first observations of the epidemic. This poses a challenge to epidemiologists: how quickly can the parameters of an emerging disease be estimated? How soon can the future progress of the epidemic be reliably predicted? We investigate these issues using a unique, spatially and temporally resolved dataset for the invasion of a plant disease, Asiatic citrus canker in urban Miami. We use epidemiological models, Bayesian Markov-chain Monte Carlo, and advanced spatial statistical methods to analyse rates and extent of spread of the disease. A rich and complex epidemic behaviour is revealed. The spatial scale of spread is approximately constant over time and can be estimated rapidly with great precision (although the evidence for long-range transmission is inconclusive). In contrast, the rate of infection is characterised by strong monthly fluctuations that we associate with extreme weather events. Uninformed predictions from the early stages of the epidemic, assuming complete ignorance of the future environmental drivers, fail because of the unpredictable variability of the infection rate. Conversely, predictions improve dramatically if we assume prior knowledge of either the main environmental trend, or the main environmental events. A contrast emerges between the high detail attained by modelling in the spatiotemporal description of the epidemic and the bottleneck imposed on epidemic prediction by the limits of meteorological predictability. We argue that identifying such bottlenecks will be a fundamental step in future modelling of weather-driven epidemics. PMID:24762851

  10. Exogenous treatment with salicylic acid attenuates occurrence of citrus canker in susceptible navel orange (Citrus sinensis Osbeck).

    PubMed

    Wang, Yin; Liu, Ji-Hong

    2012-08-15

    Citrus canker caused by Xanthomonas axonopodis pv. citri (Xac) is a devastating bacterial disease threatening the citrus industry. Salicylic acid (SA) plays a key role in plant defense response to biotic stress, but information is scarce concerning the application of SA to enhancing Xac resistance. In the present research attempts were made to investigate how exogenous application of SA influenced canker disease outbreak in navel orange (Citrus sinensis). Exogenously applied SA at 0.25 mM significantly enhanced the endogenous free and bound SA, particularly the latter. Upon exposure to Xac, lower disease incidence rate and smaller lesion sites were observed in the samples pre-treated with SA, accompanied by repression of bacterial growth at the lesion sites. Concurrent with the augmented disease resistance, SA-treated leaves had higher H?O? level and smaller stomata apertures before or after Xac infection when compared with their counterparts pre-treated with water (control). SA treatment elevated the activities of phenylalanine ammonia-lyase and ?-1,3-glucanase, but only the latter was higher in the SA-treated samples after Xac infection. In addition, mRNA levels of two pathogenesis-related genes, CsCHI and CsPR4A, were higher in the SA-treated samples relative to the control. Taken together, our results strongly suggest that the exogenously applied SA has evoked a cascade of physiological and molecular events that function singly or in concert to confer resistance to Xac invasion. PMID:22658220

  11. Production of DAPG and HCN by Pseudomonas sp. LBUM300 contributes to the biological control of bacterial canker of tomato.

    PubMed

    Lanteigne, Carine; Gadkar, Vijay J; Wallon, Thérèse; Novinscak, Amy; Filion, Martin

    2012-10-01

    Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis is known to cause significant economic losses to tomato production worldwide. Biological control has been proposed as an alternative to current chemical containment methods, which are often inefficient and may leave adverse effects on the environment. However, only little headway has so far been made in developing biocontrol strategies against C. michiganensis subsp. michiganensis. To address this knowledge gap, we investigated the antagonistic capacity of PCA, produced by Pseudomonas sp. LBUM223, and DAPG and HCN, both produced by Pseudomonas sp. LBUM300, on C. michiganensis subsp. michiganensis under in vitro and in planta conditions. Nonsynthesizing isogenic mutants of the producer strains were also developed to further dissect the role of each individual metabolite on C. michiganensis subsp. michiganensis biological control. Novel specific quantitative polymerase chain reaction TaqMan assays allowed quantification of C. michiganensis subsp. michiganensis in tomato plants and rhizospheric soil. Pseudomonas spp. LBUM223 and LBUM300 significantly repressed C. michiganensis subsp. michiganensis growth in vitro, while their respective nonproducing mutants showed less or no significant antagonistic activity. In planta, only Pseudomonas sp. LBUM300 was capable of significantly reducing disease development and C. michiganensis subsp. michiganensis rhizospheric population, suggesting that the production of both DAPG and HCN was involved. In summary, simultaneous DAPG/HCN production by Pseudomonas sp. LBUM300 shows great potential for controlling bacterial canker of tomato. PMID:22713078

  12. Genome, Proteome and Structure of a T7-Like Bacteriophage of the Kiwifruit Canker Phytopathogen Pseudomonas syringae pv. actinidiae.

    PubMed

    Frampton, Rebekah A; Acedo, Elena Lopez; Young, Vivienne L; Chen, Danni; Tong, Brian; Taylor, Corinda; Easingwood, Richard A; Pitman, Andrew R; Kleffmann, Torsten; Bostina, Mihnea; Fineran, Peter C

    2015-01-01

    Pseudomonas syringae pv. actinidiae is an economically significant pathogen responsible for severe bacterial canker of kiwifruit (Actinidia sp.). Bacteriophages infecting this phytopathogen have potential as biocontrol agents as part of an integrated approach to the management of bacterial canker, and for use as molecular tools to study this bacterium. A variety of bacteriophages were previously isolated that infect P. syringae pv. actinidiae, and their basic properties were characterized to provide a framework for formulation of these phages as biocontrol agents. Here, we have examined in more detail ?Psa17, a phage with the capacity to infect a broad range of P. syringae pv. actinidiae strains and the only member of the Podoviridae in this collection. Particle morphology was visualized using cryo-electron microscopy, the genome was sequenced, and its structural proteins were analysed using shotgun proteomics. These studies demonstrated that ?Psa17 has a 40,525 bp genome, is a member of the T7likevirus genus and is closely related to the pseudomonad phages ?PSA2 and gh-1. Eleven structural proteins (one scaffolding) were detected by proteomics and ?Psa17 has a capsid of approximately 60 nm in diameter. No genes indicative of a lysogenic lifecycle were identified, suggesting the phage is obligately lytic. These features indicate that ?Psa17 may be suitable for formulation as a biocontrol agent of P. syringae pv. actinidiae. PMID:26114474

  13. Effects of Mefenoxam, Phosphonate, and Paclobutrazol on In Vitro Characteristics of Phytophthora cactorum and P. citricola and on Canker Size of European Beech

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora citricola and P. cactorum cause bleeding cankers that lead to the death of mature European beech in the northeastern United States. Because of the economic value placed on these trees, experiments were conducted to investigate the effects of two fungicides and a plant growth regulator ...

  14. A survey of survival and activity of citrus canker lesion populations on foliage, fruit and shoots in a Florida grapefruit orchard in 2009 and 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri (Xcc)) can infect several species of citrus. The disease can develop on the leaves, shoots and fruit, causing erumpent lesions, that on fruit precludes sale to the fresh market. We assessed lesion activity in orchard-grown grapefruit to provide informa...

  15. Comparative efficiency of chemical compounds for in vitro and in vivo activity against Clavibacter michiganensis subsp. michiganensis, the causal agent of tomato bacterial canker

    Microsoft Academic Search

    Leandro de León; Felipe Siverio; María M. López; Ana Rodríguez

    2008-01-01

    Bacterial canker of tomato caused by Clavibacter michiganensis subsp. michiganensis produces considerable economic losses in many countries because effective control measures are lacking. The extent to which bactericides control this disease effectively is low and has not yet been well documented for Southern European conditions. In this study the bactericidal effect of several products on this pathogen was assessed in

  16. Processes involved in the dispersal of Xanthomonas citri pv. citri from canker-infectd citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida, and elsewhere where the pathogen occurs, and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms wit...

  17. Wind speed effects on the quantity of Xanthomonas citri subsp. citri dispersed downwind from canopies of grapefruit trees infected with citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemic of citrus canker (Xanthomonas citri subsp. citri, Xcc) in Florida continues to expand since termination of the eradication program in 2006. Storms are known to be associated with disease spread, but little information exists on the interaction of fundamental physical and biological proc...

  18. SPATIAL PATTERN ANALYSIS OF CITRUS CANKER INFECTED PLANTINGS IN SAO PAULO BRAZIL AND IMPLICATION OF THE ASIAN LEAFMINER ON POTENTIAL DISPERSAL PROCESSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eradication of Asiatic Citrus Canker (ACC) has become increasingly difficult over the last decade following the introduction of the Asian leafminer into Brazil and Florida. This prompted epidemiological studies in both countries that resulted in changes in the eradication protocols. The objective ...

  19. ESTIMATING THE INCREASE AND SPREAD OF CITRUS CANKER CAUSED BY THE INTERACTION OF PEDESTRIAN VERSUS CATASTROPHIC WEATHER EVENTS, HUMANS, AND BAD LUCK

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bacteria, Xanthomonas axonopodis pv. citri (Xac), that causes Asiatic Citrus Canker (ACC) can move in any of a variety of modes in the presence of free moisture. From a meteorological point of view, gentle rain, rain with wind, rain storms, tropical storms, and hurricanes can all disperse Xac i...

  20. STEM crisis or STEM surplus?

    E-print Network

    Xue, Yi, S.M. Massachusetts Institute of Technology

    2014-01-01

    The science, technology, engineering, and mathematics (STEM) workforce is a crucial driver of the U.S. economy. Over the last decade, there has been significant concern regarding the adequacy of the supply of STEM workers ...

  1. Overexpression of citrus polygalacturonase-inhibiting protein in citrus black rot pathogen Alternaria citri.

    PubMed

    Katoh, Hiroshi; Nalumpang, Sarunya; Yamamoto, Hiroyuki; Akimitsu, Kazuya

    2007-05-01

    The rough lemon (Citrus jambhiri) gene encoding polygalacturonase-inhibiting protein (RlemPGIPA) was overexpressed in the pathogenic fungus Alternaria citri. The overexpression mutant AcOPI6 retained the ability to utilize pectin as a sole carbon source, and the overexpression of polygalacturonase-inhibiting protein did not have any effect on the growth of AcOPI6 in potato dextrose and pectin medium. The pathogenicity of AcOPI6 to cause a black rot symptom in citrus fruits was also unchanged. Polygalacturonase-inhibiting protein was secreted together with endopolygalacturonase into culture filtrates of AcOPI6, and oligogalacturonides were digested from polygalacturonic acid by both proteins in the culture filtrates. The reaction mixture containing oligogalacturonides possessed activity for induction of defense-related gene, RlemLOX, in rough lemon leaves. PMID:17223223

  2. Cytotoxic metabolites produced by Alternaria no.28, an endophytic fungus isolated from Ginkgo biloba.

    PubMed

    Qin, Jian-Chun; Zhang, Ya-Mei; Hu, Ling; Ma, Ya-Tuan; Gao, Jin-Ming

    2009-11-01

    From the medicinal plant Ginkgo biloba the fungal endophyte Alternaria no.28 was isolated. Extract of the fungus grown in liquid culture media exhibited marked cytotoxic activity when tested in vitro against brine shrimp (Artemia salina). Eight compounds were isolated from the extract of cultures of this endophytic fungus and were elucidated as alterperylenol (1), altertoxin I (2), alternariol (3), alternariol monomethyl ether (4), tenuazonic acid (5) and its derivative (6), together with ergosterol and ergosta-4, 6, 8, 22-tetraen-3-one by means of spectroscopic analysis. Among them, both 5 and 6 showed significant cytotoxic effects in the brine shrimp bioassy, with mortality rates of 73.6% and 68.9%, respectively, at a concentration of 10 microg x mL(-1), and they were first isolated from endophytic fungi. PMID:19967976

  3. First Report of Foliar Blight on Dendropanax morbifera Caused by Alternaria panax

    PubMed Central

    Deng, Jian Xin; Kim, Chang Sun; Oh, Eun Sung

    2010-01-01

    Leaf spot and blight disease was observed on two-year-old seedlings of Dendropanax morbifera (Korean name: Hwangchil tree) during July of 2008 in Jindo Island, Korea. Symptoms included yellow-brown to dark brown irregularly enlarged spots frequently located along the veins of leaves. The lesions were often surrounded by chlorotic haloes. Severe leaf blight and subsequent defoliation occurred when conditions favored disease outbreak. The causal organism of the disease was identified as Alternaria panax based on morphological characteristics and sequence analysis of the internal transcribed spacer region of rDNA. A. panax isolates induced leaf spots and blight symptoms not only on D. morbifera but also on the other members of Araliaceae tested. This is the first report of foliar blight caused by A. panax on D. morbifera. PMID:23956672

  4. Enhancement of the citrus immune system provides effective resistance against Alternaria brown spot disease.

    PubMed

    Llorens, Eugenio; Fernández-Crespo, Emma; Vicedo, Begonya; Lapeña, Leonor; García-Agustín, Pilar

    2013-01-15

    In addition to basal defense mechanisms, plants are able to develop enhanced defense mechanisms such as induced resistance (IR) upon appropriate stimulation. We recently described the means by which several carboxylic acids protect Arabidopsis and tomato plants against fungi. In this work, we demonstrate the effectiveness of hexanoic acid (Hx) in the control of Alternaria brown spot (ABS) disease via enhancement of the immune system of Fortune mandarin. The application of 1mM Hx in irrigation water to 2-year-old Fortune plants clearly reduced the incidence of the disease and led to smaller lesions. We observed that several of the most important mechanisms involved in induced resistance were affected by Hx application. Our results demonstrate enhanced callose deposition in infected plants treated with Hx, which suggests an Hx priming mechanism. Plants treated with the callose inhibitor 2-DDG were more susceptible to the fungus. Moreover, polygalacturonase-inhibiting protein (PGIP) gene expression was rapidly and significantly upregulated in treated plants. However, treatment with Hx decreased the levels of reactive oxygen species (ROS) in infected plants. Hormonal and gene analyses revealed that the jasmonic acid (JA) pathway was activated due to a greater accumulation of 12-oxo-phytodienoic acid (OPDA) and JA along with a rapid accumulation of JA-isoleucine (JA-Ile). Furthermore, we observed a more rapid accumulation of abscisic acid (ABA), which could act as a positive regulator of callose deposition. Thus, our results support the hypothesis that both enhanced physical barriers and the JA signaling pathway are involved in hexanoic acid-induced resistance (Hx-IR) to Alternaria alternata. PMID:23260526

  5. Joint action of disease control measures: a case study of alternaria leaf blight of carrot.

    PubMed

    Ben-Noon, E; Shtienberg, D; Shlevin, E; Dinoor, A

    2003-10-01

    ABSTRACT The efficacy of chemical (i.e., foliar fungicide sprays), genetic (i.e., moderately resistant cultivars), and cultural (i.e., drip-irrigation system) control measures was quantified individually and in combination in the management of Alternaria dauci, the causal agent of Alternaria leaf blight of carrot. Whereas host resistance and drip irrigation affected both the time of disease onset and the rate of disease progression, chemical control affected only the latter. In all cases, a single control measure did not provide an acceptable level of disease suppression. Control efficacy values (based on the relative area under the disease progress curve) for chemical, genetic, and cultural control were 58 +/- 11, 39 +/- 20, and 60 +/- 22%, respectively (values are means +/- standard error). By contrast, implementing two control measures concurrently always improved disease suppression significantly compared with the individual measures. Control efficacy values were 91 +/- 8% for the integration of chemical and genetic measures and 82 +/- 23% for the integration of chemical and cultural measures. Moreover, yields in plots protected by two control measures simultaneously were higher by 10.1 to 28.6 t/ha than those in the respective plots protected by single measures. The joint effect of chemical control and host resistance was additive, whereas that of chemical control and drip irrigation was synergistic in most cases. A literature review was performed to determine if these findings represent a general relationship between chemical and genetic, and chemical and cultural measures. Based on 19 reviewed cases, it was concluded that additive effects are the rule and synergistic or antagonistic effects are the exception. Synergistic effects of two control measures were observed when one control measure improved the efficacy of the other directly or when one control measure induced host resistance or predisposed the pathogen to increased susceptibility. These results may enable a more effective selection of candidate control measures for integration in the future. PMID:18944332

  6. Distribution and Characterization of AKT Homologs in the Tangerine Pathotype of Alternaria alternata.

    PubMed

    Masunaka, A; Tanaka, A; Tsuge, T; Peever, T L; Timmer, L W; Yamamoto, M; Yamamoto, H; Akimitsu, K

    2000-07-01

    ABSTRACT The tangerine pathotype of Alternaria alternata produces a host-selective toxin (HST), known as ACT-toxin, and causes Alternaria brown spot disease of citrus. The structure of ACT-toxin is closely related to AK- and AF-toxins, which are HSTs produced by the Japanese pear and strawberry pathotypes of A. alternata, respectively. AC-, AK-, and AF-toxins are chemically similar and share a 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid moiety. Two genes controlling AK-toxin biosynthesis (AKT1 and AKT2) were recently cloned from the Japanese pear pathotype of A. alternata. Portions of these genes were used as heterologous probes in Southern blots, that detected homologs in 13 isolates of A. alternata tangerine pathotype from Minneola tangelo in Florida. Partial sequencing of the homologs in one of these isolates demonstrated high sequence similarity to AKT1 (89.8%) and to AKT2 (90.7%). AKT homologs were not detected in nine isolates of A. alternata from rough lemon, six isolates of nonpathogenic A. alternata, and one isolate of A. citri that causes citrus black rot. The presence of homologs in the Minneola isolates and not in the rough lemon isolates, nonpathogens or black rot isolates, correlates perfectly to pathogenicity on Iyo tangerine and ACT-toxin production. Functionality of the homologs was demonstrated by detection of transcripts using reverse transcription-polymerase chain reaction (RT-PCR) in total RNA of the tangerine pathotype of A. alternata. The high sequence similarity of AKT and AKT homologs in the tangerine patho-type, combined with the structural similarity of AK-toxin and ACT-toxin, may indicate that these homologs are involved in the biosynthesis of the decatrienoic acid moiety of ACT-toxin. PMID:18944496

  7. Yield loss assessment due to Alternaria blight and its management in linseed.

    PubMed

    Singh, R B; Singh, H K; Parmar, Arpita

    2014-04-01

    Field experiments were conducted during 2010-11 and 2011-12 to assess the yield losses due to Alternaria blight disease caused by Alternaria lini and A. linicola in recently released cultivars and their management with the integration of Trichoderma viride, fungicides and plant extract. Disease severity on leaves varied from 41.07% (Parvati) to 65.01% (Chambal) while bud damage per cent ranged between 23.56% (Shekhar) to 46.12% (T-397), respectively in different cultivars. Maximum yield loss of 58.44% was recorded in cultivar Neelum followed by Parvati (55.56%), Meera (55.56%) and Chambal (51.72%), respectively while minimum loss was recorded in Kiran (19.99%) and Jeevan (22.22%). Minimum mean disease severity (19.47%) with maximum disease control (69.74%) was recorded with the treatment: seed treatment (ST) with vitavax power (2 g kg(-1) seed) + 2 foliar sprays (FS) of Saaf (a mixture of carbendazim+mancozeb) 0.2% followed by ST with Trichoderma viride (4g kg(-1) seed) + 2 FS of Saaf (0.2%). Minimum bud damage (13.75%) with maximum control (60.94%) was recorded with treatment of ST with vitavax power+2 FS of propiconazole (0.2%). Maximum mean seed yield (1440 kg ha(-1)) with maximum net return (Rs. 15352/ha) and benefit cost ratio (1:11.04) was obtained with treatment ST with vitavax power + 2 FS of Neem leaf extract followed by treatment ST with vitavax power+2 FS of Saaf (1378 kg ha(-1)). PMID:25911838

  8. Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker.

    PubMed

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2015-06-01

    The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6?h and up to 72?h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120?h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (Xcc?fliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker. PMID:25231217

  9. Air pollution by allergenic spores of the genus Alternaria in the air of central and eastern Europe.

    PubMed

    Kasprzyk, Idalia; Rodinkova, Victoria; Šaulien?, Ingrida; Ritenberga, Olga; Grinn-Gofron, Agnieszka; Nowak, Malgorzata; Sulborska, Aneta; Kaczmarek, Joanna; Weryszko-Chmielewska, Elzbieta; Bilous, Elena; Jedryczka, Malgorzata

    2015-06-01

    Spores of the genus Alternaria belong to one of the most prevailing constituents of the air in all regions of the world. They form infectious inoculum of numerous plant species as well as severe inhaled allergies. The aim of this study was to compare the biological pollution with Alternaria spores of the air of 12 cities located in central and eastern Europe. The experiment was done in 2010 and it covered the territory of Latvia (LV), Lithuania (LT), Poland (PL) and Ukraine (UA). The spores were counted using an identical method and standard equipment (7-day Lanzoni volumetric sampler) followed by extensive statistical calculations. The timing of the day of maximum concentration changed mainly along the N-S direction and had a positive correlation with latitude. The most important factor determining the increase in Alternaria spore concentration was the temperature, whereas other weather parameters were not related or of low significance. Regardless of geographical location, the first phase of the season (0-0.9 % of Alternaria spores in the air) was the longest (up to 60 days) and the last (97.5 to 99 %) was the shortest (22 days or less). The means of daily concentrations of Alternaria spores ranged from 11 spores m(-3) in Klaipeda (LT, Baltic Sea coast) to 187 in Poznan (west PL, agricultural plain). The threshold value of 80 spores m(-3) that triggers the first allergy symptoms was exceeded in 8 to 86 days (Vinnitsa, UA, temperate continental, forest-steppes region). There were considerable differences between the highest number of spores per cubic metre of air, varying from 139 in the north (Klaipeda, LT) to 2,295 in central west (Poznan, PL). The biological pollution by Alternaria spores in several places of central and eastern Europe was high; the number of days exceeding the threshold value of 300 spores m(-3) connected with serious health problems of atopic people ranged from 0 to 1 on the north (LV, LT) to 29 in central west (Poznan, PL). PMID:25592912

  10. Alternaria-Associated Fungus Ball of Orbit Nose and Paranasal Sinuses: Case Report of a Rare Clinical Entity.

    PubMed

    Pesic, Zoran; Otasevic, Suzana; Mihailovic, Dragan; Petrovic, Sladjana; Arsic-Arsenijevic, Valentina; Stojanov, Dragan; Petrovic, Milica

    2015-08-01

    Alternaria-associated fungus ball of maxillar, ethmoidal paranasal sinuses, nasal cavity and orbit with bone erosion is extremely rare. Till recently, only two cases of this infection in immune competitive patients have been reported. We are herein describing the case of immune-competent woman who suffered of nasal congestion for 10 years. Patient was treated for tumor-like lesion in right maxillar sinus, where propagation in right nose cavity, right ethmoidal cells and right orbita was present. The organism that was seen in surgical removal of fungal debris by histological study, in using mycological testing, was proven as Alternaria alternata. Combination of surgical intervention and treatment with itraconazole eradicated fungal infection, and the disease was not relapsed in follow-up period of 2 years. PMID:25749849

  11. Evaluation of an indigenous isolate of Alternaria alternata (LC#508) for use as a mycoherbicide for Lantana camara L

    Microsoft Academic Search

    Sanjai Saxena; Akhilesh K. Pandey

    2002-01-01

    Bioherbicides are speciality biotechnology products that offer a non-chemical alternative to control of noxious weeds with the goal of reducing the input of harmful chemicals into the environment. This paper evaluates the potential of an indigenous isolate of Alternaria alternata (LC#508) for use as a mycoherbicide for Lantana camara, a global weed. A spore inoculum of 1.65×106 spores\\/ml induced mortality

  12. Somatic hybrids between Brassica oleracea L. and Sinapis alba L. with resistance to Alternaria brassicae (Berk.) Sacc

    Microsoft Academic Search

    L. N. Hansen; E. D. Earle

    1997-01-01

    Somatic Hybrids between Sinapis alba and rapid-cycling Brassica oleracea were generated for transferring of resistance to Alternaria brassicae to B. oleracea. A. brassicae causes the significant disease black spot in cruciferous crops. A total of 27 plants were regenerated from protoplast fusion\\u000a using 0, 5, 10, 20 and 30 krad ?-irradiation of the resistance donor and iodoacetate treatment of B.

  13. Effect of climate change on Alternaria leaf spot of rocket salad and black spot of basil under controlled environment.

    PubMed

    Pugliese, M; Cogliati, E; Gullino, M L; Garibaldi, A

    2012-01-01

    Plant responses to elevated CO2 and temperature have been much studied in recent years, but effects of climate change on pathological responses are still largely unknown. The pathosystems rocket (Eruca vesicaria subsp. sativa)--Alternaria leaf spot (Alternaria japonica) and basil (Ocimum basilicum)--black spot (Colletotrichum gloeosporioides) were chosen as models to assess the potential impact of increased CO2 and temperature on disease incidence and severity under controlled environment. Potted plants were grown in phytotrons under 4 different simulated climatic conditions: (1) standard temperature (ranging from 18 degrees to 22 degrees C) and standard CO2 concentration (400 ppm); (2) standard temperature and elevated CO2 concentration (800 ppm); (3) elevated temperature (ranging from 22 degrees to 26 degrees C, 4 degrees C higher than standard) and standard CO2 concentration; (4) elevated temperature and CO2 concentration. Each plant was inoculated with a spore suspension containing 1 x 10(5) cfu/ml of the pathogen. Disease incidence and severity were assessed 14 days after inoculation. Increasing CO2 to 800 ppm showed a clear increment in the percentage of Alternaria leaf spot on rocket leaves compared to standard conditions. Basil plants grown at 800 ppm of CO2 showed increased black spot symptoms compared to 400 ppm. Disease incidence and severity were always influenced by the combination of rising CO2 and increased temperature, compared to standard conditions (400 ppm of CO2 - 22 degrees C). Considering the rising concentrations of CO2 and global temperature, we can assume that this could increase the severity of Alternaria japonica on rocket and Colletotrichum gloeosporioides on basil. PMID:23878979

  14. Epoxide hydrolase: a mRNA induced by the fungal pathogen Alternaria alternata on rough lemon ( Citrus jambhiri Lush)

    Microsoft Academic Search

    Kenji Gomi; Hiroyuki Yamamato; Kazuya Akimitsu

    2003-01-01

    An expression profile of genes induced by non-pathogenic Alternaria alternata on rough lemon leaves was obtained by sequencing 500 subtractive PCR clones generated from mRNA of leaves inoculated with the fungus after subtraction with that of non-inoculated leaves. About 6% of the cDNA sequences had homology to known putative defense-related genes including epoxide hydrolase. A full-length cDNA (951 bp) from rough

  15. A cDNA Encoding Polygalacturonase-inhibiting Protein Induced in Citrus Leaves by Polygalacturonase of Alternaria citri

    Microsoft Academic Search

    Yukie GOTOH; Sarunya NALUMPANG; Atsunori ISSHIKI; Takami UTSUMI; Kenji GOMI; Hiroyuki YAMAMOTO; Kazuya AKIMITSU

    2002-01-01

      A cDNA encoding the polygalacturonase-inhibiting protein gene (RlemPGIPl) was identified from rough lemon (Citrus jambhiri Lush.). The deduced amino acid sequence is 46-75% identical to other plant PGIPs. The transcripts of the PGIP gene were weakly\\u000a but constitutively expressed in leaves and increased in leaves within 30 min after wounding or inoculation with nonpathogenic\\u000a Alternaria alternata or A. citri. However,

  16. Crop harvest in Denmark and Central Europe contributes to the local load of airborne Alternaria spore concentrations in Copenhagen

    NASA Astrophysics Data System (ADS)

    Skjøth, C. A.; Sommer, J.; Frederiksen, L.; Gosewinkel Karlson, U.

    2012-11-01

    This study examines the hypothesis that Danish agricultural areas are the main source of airborne Alternaria spores in Copenhagen, Denmark. We suggest that the contribution to the overall load is mainly local or regional, but with intermittent long distance transport (LDT) from more remote agricultural areas. This hypothesis is supported by investigating a 10 yr bi-hourly record of Alternaria spores in the air from Copenhagen. This record shows 232 clinically relevant episodes (daily average spore concentration above 100 m-3) with a distinct daily profile. The data analysis also revealed potential LDT episodes almost every year. A source map and analysis of atmospheric transport suggest that LDT always originates from the main agricultural areas in Central Europe. A dedicated emission study in cereal crops under harvest during 2010 also supports our hypothesis. The emission study showed that although the fields had been treated against fungal infections, harvesting still produced large amounts of airborne fungal spores. It is likely that such harvesting periods can cause clinically relevant levels of fungal spores in the atmosphere. Our findings suggest that crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen as well as other urban areas in this region. It is likely that such episodes could be simulated using atmospheric transport models.

  17. Efficacy of heat treatment for the thousand cankers disease vector and pathogen in small black walnut logs.

    PubMed

    Mayfield, A E; Fraedrich, S W; Taylor, A; Merten, P; Myers, S W

    2014-02-01

    Thousand cankers disease, caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and an associated fungal pathogen (Geosmithia morbida M. Kolarík, E. Freeland, C. Utley, and N. Tisserat), threatens the health and commercial use of eastern black walnut (Juglans nigra L.), one of the most economically valuable tree species in the United States. Effective phytosanitary measures are needed to reduce the possibility of spreading this insect and pathogen through wood movement. This study evaluated the efficacy of heat treatments and debarking to eliminate P. juglandis and C. morbida in J. nigra logs 4-18 cm in diameter and 30 cm in length. Infested logs were steam heated until various outer sapwood temperatures (60, 65, and 70 degrees C in 2011; 36, 42, 48, 52, and 56 degrees C in 2012) were maintained or exceeded for 30-40 min. In 2011, all heat treatments eliminated G. morbida from the bark, but logs were insufficiently colonized by P. juglandis to draw conclusions about treatment effects on the beetle. Debarking did not ensure elimination of the pathogen from the sapwood surface. In 2012, there was a negative effect of increasing temperature on P. juglandis emergence and G. morbida recovery. G. morbida did not survive in logs exposed to treatments in which minimum temperatures were 48 degrees C or higher, and mean P. juglandis emergence decreased steadily to zero as treatment minimum temperature increased from 36 to 52 degrees C. A minimum outer sapwood temperature of 56 degrees C maintained for 40 min is effective for eliminating the thousand cankers disease vector and pathogen from walnut logs, and the current heat treatment schedule for the emerald ash borer (60 degrees C core temperature for 60 min) is more than adequate for treating P. juglandis and G. morbida in walnut firewood. PMID:24665700

  18. STEM Thinking!

    ERIC Educational Resources Information Center

    Reeve, Edward M.

    2015-01-01

    Science, Technology, Engineering, and Mathematics (STEM) is a term seen almost daily in the news. In 2009, President Obama launched the Educate to Innovate initiative to move American students from the middle to the top of the pack in science and math achievement over the next decade (The White House, n.d.). Learning about the attributes of STEM

  19. Stem Cells

    Microsoft Academic Search

    Gwen Lomberk

    2007-01-01

    In this issue, ‘Pancreatology and the Web’ focuses on stem cell research, one of the 21st century’s most exciting areas of science. Stem cell research has been advancing our knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Although still in its infancy, this field also offers a revolutionary

  20. Natural Occurrence of Alternaria Toxins in Wheat-Based Products and Their Dietary Exposure in China

    PubMed Central

    Zhao, Kai; Shao, Bing; Yang, Dajin; Li, Fengqin; Zhu, Jianghui

    2015-01-01

    A total of 181 wheat flour and 142 wheat-based foods including dried noodle, steamed bread and bread collected in China were analyzed for alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN) and tenuazonic acid (TeA) by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. TeA was the predominant toxin found in 99.4% wheat flour samples at levels ranging from 1.76 ?g/kg to 520 ?g/kg. TEN was another Alternaria toxin frequently detected in wheat flour samples (97.2%) at levels between 2.72 ?g/kg and 129 ?g/kg. AOH and AME were detected in 11 (6.1%) samples at levels ranging from 16.0 ?g/kg to 98.7 ?g/kg (AOH) and in 165 (91.2%) samples with a range between 0.320 ?g/kg and 61.8 ?g/kg (AME). AOH was quantified at higher levels than AME with the ratio of AOH/AME ranging from 1.0 to 3.7. Significant linear regressions of correlation in toxin concentrations were observed between AOH and AME, AME and TeA, TEN and TeA, AOH+AME and TeA. At an average and 95th percentile, dietary exposure to AOH and AME in the Chinese general population and different age subgroups exceeded the relevant threshold value of toxicological concern (TTC), with the highest exposure found in children which deserves human health concern. TEN and TeA seem unlikely to be health concerns for the Chinese via wheat-based products but attention should be paid to synergistic or additive effects of TeA with AOH, AME, TEN and a further assessment will be performed once more data on toxicity-guided fractionation of the four toxins are available. It is necessary to conduct a systemic surveillance of Alternaria toxins in raw and processed foods in order to provide the scientific basis for making regulations on these toxins in China. PMID:26121047

  1. Survival, growth, and target canker infection of black walnut families 15 years after establishment in West Virginia. Forest Service research paper (Final)

    SciTech Connect

    Schuler, T.M.

    1993-07-01

    The survival, growth, and rate of target canker infection of 34 black walnut (Juglans nigra) families were evaluated 15 years after establishment in north-central West Virginia. The progenies originated at locations in Pennsylvania, West Virginia, Tennessee, and North Carolina. There were significant differences between families in survival, incidence of target-canker infection, total height, and diameter at breast height. The North Carolina and Tennessee sources were less suitable for the growing conditions of the test site, local and slightly more northern sources seem more suitable. Near the northern extremity of the range of black walnut, maintaining a viable native population of this species and using local seed sources in artificial regeneration activities are recommended.

  2. Secretome Analysis Reveals an Arabidopsis Lipase Involved in Defense against Alternaria brassicicolaW?

    PubMed Central

    Oh, Il Seok; Park, Ae Ran; Bae, Min Seok; Kwon, Sun Jae; Kim, Young Soon; Lee, Ji Eun; Kang, Na Young; Lee, Sumin; Cheong, Hyeonsook; Park, Ohkmae K.

    2005-01-01

    The Arabidopsis thaliana secretome was analyzed by the proteomic approach, which led to the identification of secreted proteins implicated in many aspects of cell biology. We then investigated the change in the Arabidopsis secretome in response to salicylic acid and identified several proteins involved in pathogen response. One of these, a secreted lipase with a GDSL-like motif designated GDSL LIPASE1 (GLIP1), was further characterized for its function in disease resistance. glip1 plants were markedly more susceptible to infection by the necrotrophic fungus Alternaria brassicicola compared with the parental wild-type plants. The recombinant GLIP1 protein possessed lipase and antimicrobial activities that directly disrupt fungal spore integrity. Furthermore, GLIP1 appeared to trigger systemic resistance signaling in plants when challenged with A. brassicicola, because pretreatment of the glip1 mutant with recombinant GLIP1 protein inhibited A. brassicicola–induced cell death in both peripheral and distal leaves. Moreover, glip1 showed altered expression of defense- and ethylene-related genes. GLIP1 transcription was increased by ethephon, the ethylene releaser, but not by salicylic acid or jasmonic acid. These results suggest that GLIP1, in association with ethylene signaling, may be a critical component in plant resistance to A. brassicicola. PMID:16126835

  3. Production of a Thermostable ?-d-Galactosidase by Alternaria alternata Grown in Whey

    PubMed Central

    Macris, Basil J.

    1982-01-01

    In the course of exploring new microbial sources of extracellular ?-d-galactosidase (EC. 3.2.1.23), Alternaria alternata was found to excrete elevated quantities of a thermostable form of the enzyme when cultivated in whey growth medium. Optimum cultural conditions for maximum enzyme production were a whey lactose concentration of 6%, supplementation of the medium with 0.050 M (NH4)2SO4, an inoculum size of 103 conidia per ml, and a cultivation time at 28 to 30°C of 5 days. The fungus utilized whey lactose for the production of the enzyme most efficiently, and the observed maximum yield, 280 nanokatals of hydrolyzed o-nitrophenyl-?-d-galactopyranoside per g of whey lactose, was comparable to maximum yields reported for certain commercial fungi. The optimum pH and temperature of the enzymatic reaction were 4.5 to 5.5 and 60 to 70°C, respectively, and the enzyme lost half of its activity when heated at 65°C for 84 min. These properties make the enzyme particularly suitable for processing acid and less-acid (pH 5 to 6) dairy products and by-products. PMID:16346127

  4. Enzymatic activities of Alternaria alternata allergenic extracts and its major allergen (Alt a 1).

    PubMed

    Sáenz-de-Santamaría, Miriam; Guisantes, Jorge A; Martínez, Jorge

    2006-07-01

    Several allergens from Alternaria alternata have been isolated allowing some of them to be identified and characterised. Despite the fact that the major allergen of A. alternata (Alt a 1) has been extensively produced by recombinant technology, its biological activity still remains unknown. In the present study, extracts from culture filtrates were used to evaluate the intra-specific variability of the enzymes and also as a source for isolating and purifying native Alt a 1. This was purified by affinity chromatography using antibody anti-recombinant Alt a 1 (produced in Escherichia coli). Enzyme activities were analysed by the API-ZYM System screening method. Results demonstrated the high variability of enzyme activities among the different strains. Only activities corresponding to phosphatases, esterases and beta-glucosidase were expressed by 100% of the strains. Both native and recombinant Alt a 1 showed phosphatase and esterase activities, suggesting that the glucidic moiety of this allergen does not significantly affect its enzyme activity. PMID:16784442

  5. Biosynthesis and role in virulence of the histone deacetylase inhibitor depudecin from Alternaria brassicicola.

    PubMed

    Wight, Wanessa D; Kim, Kwang-Hyung; Lawrence, Christopher B; Walton, Jonathan D

    2009-10-01

    Depudecin, an eleven-carbon linear polyketide made by the pathogenic fungus Alternaria brassicicola, is an inhibitor of histone deacetylase (HDAC). A chemically unrelated HDAC inhibitor, HC toxin, was earlier shown to be a major virulence factor in the interaction between Cochliobolus carbonum and its host, maize. In order to test whether depudecin is also a virulence factor for A. brassicicola, we identified the genes for depudecin biosynthesis and created depudecin-minus mutants. The depudecin gene cluster contains six genes (DEP1 to DEP6), which are predicted to encode a polyketide synthase (AbPKS9 or DEP5), a transcription factor (DEP6), two monooxygenases (DEP2 and DEP4), a transporter of the major facilitator superfamily (DEP3), and one protein of unknown function (DEP1). The involvement in depudecin production of DEP2, DEP4, DEP5, and DEP6 was demonstrated by targeted gene disruption. DEP6 is required for expression of DEP1 through DEP5 but not the immediate flanking genes, thus defining a coregulated depudecin biosynthetic cluster. The genes flanking the depudecin gene cluster but not the cluster itself are conserved in the same order in the related fungi Stagonospora nodorum and Pyrenophora tritici-repentis. Depudecin-minus mutants have a small (10%) but statistically significant reduction in virulence on cabbage (Brassica oleracea) but not on Arabidopsis. The role of depudecin in virulence is, therefore, less dramatic than that of HC toxin. PMID:19737099

  6. Changes in concentration of Alternaria and Cladosporium spores during summer storms

    NASA Astrophysics Data System (ADS)

    Grinn-Gofro?, Agnieszka; Strzelczak, Agnieszka

    2013-09-01

    Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004-2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms.

  7. Optimization of protease production by endophytic fungus, Alternaria alternata, isolated from an Australian native plant.

    PubMed

    Zaferanloo, Bita; Quang, Trung D; Daumoo, Smita; Ghorbani, Mahmood M; Mahon, Peter J; Palombo, Enzo A

    2014-06-01

    Endophytes are recognised as potential sources of novel secondary metabolites, including enzymes and drugs, with applications in medicine, agriculture and industry. There is a growing need for new enzymes, including proteases, for use in industry that can function under a variety of conditions. In this study, three fungal endophytes (Alternaria alternata, Phoma herbarum and an unclassified fungus), were isolated from the Australian native plant, Eremophilia longifolia, and assessed for production of proteases. The lyophilised growth media obtained after fungal fermentation were analysed for protease production using enzyme activity assays. Protease production was optimised by assessing the effects of temperature, pH, carbon source and nitrogen source on activity. A. alternata showed the greatest protease activity in a wide range of pH (3-9). The broadest activity between 9 and 50 °C was observed at pH 7, suggesting a neutral protease. Overall, the optimum conditions were 37 °C and pH 7 with a maximum specific activity value of 69.86 BAEE units/mg. The characteristics demonstrated by this fungal endophyte showed that it is a potential source of an enzyme with particular application in the dairy industry. However, further studies of the tolerance to higher temperatures and pH will indicate whether the enzyme is suitable to such applications. PMID:24419660

  8. Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola

    PubMed Central

    Calmes, Benoit; Guillemette, Thomas; Teyssier, Lény; Siegler, Benjamin; Pigné, Sandrine; Landreau, Anne; Iacomi, Béatrice; Lemoine, Rémi; Richomme, Pascal; Simoneau, Philippe

    2013-01-01

    In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e., a mannitol dehydrogenase (AbMdh), and a mannitol-1-phosphate dehydrogenase (AbMpd). Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behavior were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle. PMID:23717316

  9. acetylcholinesterase inhibitory potential and insecticidal activity of an endophytic Alternaria sp. from Ricinus communis.

    PubMed

    Singh, Bahaderjeet; Thakur, Abhinay; Kaur, Sanehdeep; Chadha, B S; Kaur, Amarjeet

    2012-11-01

    Keeping in view the vast potential of endophytic fungi to produce bioactive molecules, this study aimed at isolating and screening endophytes for the production of acetylcholinesterase inhibitors. Fifty-four endophytic fungi were isolated from Ricinus communis and screened for their AChE inhibitory activity using Ellman's colorimetric assay method. Six isolates were found to possess AChE inhibitory activity with maximum inhibition of 78 % being evinced by culture Cas1 which was identified to be Alternaria sp. on the basis of molecular as well as microscopic methods. Optimization of inhibitor production was carried out using one factor at a time approach. Maximum production of inhibitor was obtained on potato dextrose broth after 10 days incubation. The IC(50) of the chloroform extract was observed to be 40 ?g/ml. The extract was purified on silica gel and eluted stepwise with a gradient of chloroform/methanol. The insecticidal potential of the extract was evaluated by feeding the larvae of Spodoptera litura on diet containing varying concentrations of the extract. It was observed that with increase in the concentration of the extract, mortality of the larvae increased. The culture has the potential of being exploited in medicine as well as a biocontrol agent. PMID:22945561

  10. Induction of disease resistance by the plant activator, acibenzolar- S-methyl (ASM), against bacterial canker ( Clavibacter michiganensis subsp. michiganensis) in tomato seedlings

    Microsoft Academic Search

    Soner Soylu; Ömür Baysal; E. Mine Soylu

    2003-01-01

    The plant defence activator acibenzolar-S-methyl (benzo [1,2,3]thiadiazole-7-carbothioic acid-S-methyl ester, ASM; Bion 50 WG) was assayed on tomato seedlings for its ability to induce resistance against Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial canker of tomato. Pre-treatment of plants with ASM reduced the severity of the disease as well as the growth of the bacteria in planta. In

  11. Contribution of Peroxisomes to Secondary Metabolism and Pathogenicity in the Fungal Plant Pathogen Alternaria alternata ? †

    PubMed Central

    Imazaki, Ai; Tanaka, Aiko; Harimoto, Yoshiaki; Yamamoto, Mikihiro; Akimitsu, Kazuya; Park, Pyoyun; Tsuge, Takashi

    2010-01-01

    The filamentous fungus Alternaria alternata includes seven pathogenic variants (pathotypes) which produce different host-selective toxins and cause diseases on different plants. The Japanese pear pathotype produces the host-selective AK-toxin, an epoxy-decatrienoic acid ester, and causes black spot of Japanese pear. Previously, we identified four genes, AKT1, AKT2, AKT3, and AKTR, involved in AK toxin biosynthesis. AKT1, AKT2, and AKT3 encode enzyme proteins with peroxisomal targeting signal type 1 (PTS1)-like tripeptides, SKI, SKL, and PKL, respectively, at the C-terminal ends. In this study, we verified the peroxisome localization of Akt1, Akt2, and Akt3 by using strains expressing N-terminal green fluorescent protein (GFP)-tagged versions of the proteins. To assess the role of peroxisome function in AK-toxin production, we isolated AaPEX6, which encodes a peroxin protein essential for peroxisome biogenesis, from the Japanese pear pathotype and made AaPEX6 disruption-containing transformants from a GFP-Akt1-expressing strain. The ?AaPEX6 mutant strains did not grow on fatty acid media because of a defect in fatty acid ? oxidation. The import of GFP-Akt1 into peroxisomes was impaired in the ?AaPEX6 mutant strains. These strains completely lost AK toxin production and pathogenicity on susceptible pear leaves. These data show that peroxisomes are essential for AK-toxin biosynthesis. The ?AaPEX6 mutant strains showed a marked reduction in the ability to cause lesions on leaves of a resistant pear cultivar with defense responses compromised by heat shock. This result suggests that peroxisome function is also required for plant invasion and tissue colonization in A. alternata. We also observed that mutation of AaPEX6 caused a marked reduction of conidiation. PMID:20348386

  12. Modulation of Alternaria infectoria Cell Wall Chitin and Glucan Synthesis by Cell Wall Synthase Inhibitors

    PubMed Central

    Fernandes, Chantal; Anjos, Jorge; Walker, Louise A.; Silva, Branca M. A.; Cortes, Luísa; Mota, Marta; Munro, Carol A.; Gow, Neil A. R.

    2014-01-01

    The present work reports the effects of caspofungin, a ?-1,3-glucan synthase inhibitor, and nikkomycin Z, an inhibitor of chitin synthases, on two strains of Alternaria infectoria, a melanized fungus involved in opportunistic human infections and respiratory allergies. One of the strains tested, IMF006, bore phenotypic traits that conferred advantages in resisting antifungal treatment. First, the resting cell wall chitin content was higher and in response to caspofungin, the chitin level remained constant. In the other strain, IMF001, the chitin content increased upon caspofungin treatment to values similar to basal IMF006 levels. Moreover, upon caspofungin treatment, the FKS1 gene was upregulated in IMF006 and downregulated in IMF001. In addition, the resting ?-glucan content was also different in both strains, with higher levels in IMF001 than in IMF006. However, this did not provide any advantage with respect to echinocandin resistance. We identified eight different chitin synthase genes and studied relative gene expression when the fungus was exposed to the antifungals under study. In both strains, exposure to caspofungin and nikkomycin Z led to modulation of the expression of class V and VII chitin synthase genes, suggesting its importance in the robustness of A. infectoria. The pattern of A. infectoria phagocytosis and activation of murine macrophages by spores was not affected by caspofungin. Monotherapy with nikkomycin Z and caspofungin provided only fungistatic inhibition, while a combination of both led to fungal cell lysis, revealing a strong synergistic action between the chitin synthase inhibitor and the ?-glucan synthase inhibitor against this fungus. PMID:24614372

  13. Fungal-specific transcription factor AbPf2 activates pathogenicity in Alternaria brassicicola.

    PubMed

    Cho, Yangrae; Ohm, Robin A; Grigoriev, Igor V; Srivastava, Akhil

    2013-08-01

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. To identify molecular determinants of pathogenicity, we created non-pathogenic mutants of a transcription factor-encoding gene, AbPf2. The frequency and timing of germination and appressorium formation on host plants were similar between the non-pathogenic ?abpf2 mutants and wild-type A. brassicicola. The mutants were also similar in vitro to wild-type A. brassicicola in terms of vegetative growth, conidium production, and responses to a phytoalexin, reactive oxygen species and osmolites. The hyphae of the mutants grew slowly but did not cause disease symptoms on the surface of host plants. Transcripts of the AbPf2 gene increased exponentially soon after wild-type conidia contacted their host plants . A small amount of AbPf2 protein, as monitored using GFP fusions, was present in young, mature conidia. The protein level decreased during saprophytic growth, but increased and was located primarily in fungal nuclei during pathogenesis. Levels of the proteins and transcripts sharply decreased following colonization of host tissues beyond the initial infection site. When expression of the transcription factor was induced in the wild-type during early pathogenesis, 106 fungal genes were also induced in the wild-type but not in the ?abpf2 mutants. Notably, 33 of the 106 genes encoded secreted proteins, including eight putative effector proteins. Plants inoculated with ?abpf2 mutants expressed higher levels of genes associated with photosynthesis, the pentose phosphate pathway and primary metabolism, but lower levels of defense-related genes. Our results suggest that AbPf2 is an important regulator of pathogenesis, but does not affect other cellular processes in A. brassicicola. PMID:23617599

  14. Comparison of methodologies for conidia production by Alternaria alternata from citrus.

    PubMed

    Carvalho, Daniel D C; Alves, Eduardo; Batista, Tereza R S; Camargos, Renato B; Lopes, Eloísa A G L

    2008-10-01

    Conidia production is a problem in the study of Alternaria alternata from citrus. Thus, this study aimed to compare existing methodologies for conidial production of A. alternata isolated from Ponkan tangerine (2 isolates), Cravo lemon (1 isolate), Pêra orange (2 isolates) and Murcott tangor (1 isolate). The methodologies used were conidia production with 12 and 24 hours under white fluorescent light, evaluation with 24 and 48 hours after applying fungal mycelium stress technique, cold stress followed by injury of mycelium and evaluation with 24 hours, using healthy vegetable tissue and the use of black fluorescent near ultraviolet (NUV) lamp. Satisfactory result was obtained with A. alternata isolate from Murcott tangor, with the production of 2.8 × 10(5) conidia mL(-1), when fungal mycelium was stressed (Petri dish with 66.66% of fungi growth) and subsequently 24 h of growth. The use of white light (24 h) and black fluorescent NUV lamp also induced expressive conidia production by one isolate of Ponkan tangerine, which produced 17.2 × 10(5) and 10.1 × 10(5)conidia mL(-1) and another of Murcott tangor, which produced 13.9 × 10(5) and 10.1 × 10(5) conidia mL(-1), respectively. The remaining methodologies analyzed in this study were not able to induce conidia production in satisfactory quantity. The use of both mycelium stress technique and white light (24 h) and black fluorescent NUV lamp allowed the production of enough quantities of conidia to be used in vitro (detection of fungitoxic substances) and in vivo (pathogenicity test) assays, respectively. PMID:24031309

  15. Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola

    SciTech Connect

    Cho, Yangrae; Srivastava, Akhil; Ohm, Robin A.; Lawrence, Christopher B.; Wang, Koon-Hui; Grigoriev, Igor V.; Marahatta, Sharadchandra P.

    2012-05-01

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC) were nonpathogenic and another gene (AbVf8) caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of ?amr1 and characterized their phenotypes. The ?amr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  16. Isolation and partial characterization of bacteriophages infecting Pseudomonas syringae pv. actinidiae, causal agent of kiwifruit bacterial canker.

    PubMed

    Di Lallo, Gustavo; Evangelisti, Matteo; Mancuso, Francesco; Ferrante, Patrizia; Marcelletti, Simone; Tinari, Antonella; Superti, Fabiana; Migliore, Luciana; D'Addabbo, Pietro; Frezza, Domenico; Scortichini, Marco; Thaller, Maria Cristina

    2014-11-01

    The phytopathogen Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of bacterial canker of kiwifruit. In the last years, it has caused severe economic losses to Actinidia spp. cultivations, mainly in Italy and New Zealand. Conventional strategies adopted did not provide adequate control of infection. Phage therapy may be a realistic and safe answer to the urgent need for novel antibacterial agents aiming to control this bacterial pathogen. In this study, we described the isolation and characterization of two bacteriophages able to specifically infect Psa. ?PSA1, a member of the Siphoviridae family, is a temperate phage with a narrow host range, a long latency, and a burst size of 178; ?PSA2 is a lytic phage of Podoviridae family with a broader host range, a short latency, a burst size of 92 and a higher bactericidal activity as determined by the TOD value. The genomic sequence of ?PSA1 has a length of 51,090?bp and a low sequence homology with the other siphophages, whereas ?PSA2 has a length of 40?472?bp with a 98% homology with Pseudomonas putida bacteriophage gh-1. Of the two phages examined, ?PSA2 may be considered as a candidate for phage therapy of kiwifruit disease, while ?PSA1 seems specific toward the recent outbreak's isolates and could be useful for Psa typing. PMID:24810619

  17. Genetic differentiation and spatial structure of Geosmithia morbida, the causal agent of thousand cankers disease in black walnut (Juglans nigra).

    PubMed

    Hadziabdic, Denita; Vito, Lisa M; Windham, Mark T; Pscheidt, Jay W; Trigiano, Robert N; Kolarik, Miroslav

    2014-05-01

    The main objectives of this study were to evaluate genetic composition of Geosmithia morbida populations in the native range of black walnut and provide a better understanding regarding demography of the pathogen. The fungus G. morbida, and the walnut twig beetle, Pityophthorus juglandis, have been associated with a disease complex of black walnut (Juglans nigra) known as thousand cankers disease (TCD). The disease is manifested as branch dieback and canopy loss, eventually resulting in tree death. In 2010, the disease was detected in black walnut in Tennessee, and subsequently in Virginia and Pennsylvania in 2011 and North Carolina in 2012. These were the first incidences of TCD east of Colorado, where the disease has been established for more than a decade on indigenous walnut species. A genetic diversity and population structure study of 62 G. morbida isolates from Tennessee, Pennsylvania, North Carolina and Oregon was completed using 15 polymorphic microsatellite loci. The results revealed high haploid genetic diversity among seven G. morbida populations with evidence of gene flow, and significant differentiation among two identified genetic clusters. There was a significant correlation between geographic and genetic distance. Understanding the genetic composition and demography of G. morbida can provide valuable insight into recognizing factors affecting the persistence and spread of an invasive pathogen, disease progression, and future infestation predictions. Overall, these data support the hypotheses of two separate, highly diverse pathogen introductions into the native range of black walnut. PMID:24177436

  18. A new method for detection of five alternaria toxins in food matrices based on LC-APCI-MS.

    PubMed

    Prelle, Ambra; Spadaro, Davide; Garibaldi, Angelo; Gullino, Maria Lodovica

    2013-09-01

    A new method for the detection of alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), tentoxin (TEN), and tenuazonic acid (TeA), five alternaria toxins (ATs) was developed by liquid chromatography-triple quadrupole mass spectrometry equipped with atmospheric pressure chemical ionisation (APCI). A single extraction was used to recover the five ATs by apple juices, beers, tomato sauces, olives and dried basil. Different Solid Phase Extractions (SPE) and clean-up were selected to optimise the purification step for each food matrix. Limits of detection and quantification were, respectively, in the range 0.16-12.31 and 0.54-41.04 ng g(-1). Recovery rates were generally above 70%, except for dried basil and olives. Thirty out of 70 samples analysed (7 apple juices, 14 beers and 9 tomato sauces) resulted positive to at least one alternaria toxin investigated. AOH was the most common AT (14 samples), followed by ALT (10 samples). The highest concentration of ATs was found in commercial apple juices (35.33 ng g(-1)). PMID:23578628

  19. Involvement of an extracellular fungus laccase in the flavonoid metabolism in Citrus fruits inoculated with Alternaria alternata.

    PubMed

    Díaz, Licinio; Del Río, José Antonio; Pérez-Gilabert, Manuela; Ortuño, Ana

    2015-04-01

    Fungi of the genus Alternaria are responsible for substantial pre-harvest losses in Citrus. In this study a degradative metabolism of flavonoids (flavanones, flavones and polymethoxyflavones) was observed when 'Fortune' mandarin, Citrus limon and Citrus paradisi, fruits were inoculated with Alternaria alternata, a pre-harvest pathogenic fungus. Associated to this flavonic metabolism the de novo synthesis of the phytoalexin scoparone was detected. This metabolism of flavonoids is caused by an extracellular fungus laccase. The kinetic characterisation of this enzyme revealed that the activity was induced by Citrus flavonoids and was dependent on flavonoid concentrations. The enzyme exhibited a Km of 1.9 mM using ABTS as substrate with an optimum pH of 3.5 in citrate buffer 100 mM. The enzyme is active between 15 and 45 °C, the optimum temperature being around 35 °C, although 50% of the initial activity is lost after 45 min at 35 °C. The A. alternata laccase was inhibited by 0.5 mM l-cysteine and by caffeic acid. Study of the substrate specificity of this enzyme revealed that Citrus flavonoids are substrates of A. alternata laccase. These results suggest that the laccase enzyme could be involved in the pathogenesis of A. alternata in Citrus. PMID:25686700

  20. Environmental Factors Affecting Production, Release, and Field Populations of Conidia of Alternaria alternata, the Cause of Brown Spot of Citrus.

    PubMed

    Timmer, L W; Solel, Z; Gottwald, T R; Ibañez, A M; Zitko, S E

    1998-11-01

    ABSTRACT Alternaria brown spot, caused by Alternaria alternata pv. citri, affects many tangerines and their hybrids, causing loss of immature leaves and fruit and reducing the marketability of the remaining fruit. Conidial production of A. alternata was greatest on mature leaves moistened and maintained at near 100% relative humidity (RH) for 24 h, whereas leaves that had been soaked or maintained at moderate RH produced few conidia. Conidial release from filter paper cultures and infected leaves was studied in a computer-controlled environmental chamber. Release of large numbers of conidia was triggered from both substrates by sudden drops in RH or by simulated rainfall events. Vibration induced release of low numbers of conidia, but red/infrared irradiation had no effect. In field studies from 1994 to 1996, air sampling with a 7-day recording volumetric spore trap indicated that conidia were present throughout the year with periodic large peaks. The number of conidia captured was not closely related to rainfall amounts or average wind speed, but was weakly related to the duration of leaf wetness. Likewise, disease severity on trap plants placed in the field weekly during 1995 to 1996 was not closely related to conidial numbers or rainfall amounts, but was weakly related to leaf wetness duration. Sufficient inoculum appears to be available to allow infection to occur throughout the year whenever susceptible host tissue and moisture are available. PMID:18944857

  1. Expression of ß-1,3-glucanase and ß-1,4-glucanase in two potato cultivars following challenge by the fungal pathogen Alternaria solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. We have previously found that variation in resistance phenotypes exist between two different Iranian cultivars of potato. Cultivar ‘Diamond’ is more resistant to multiple isolates of A. s...

  2. Multiple Epoxide Hydrolases in Alternaria alternata f. sp. lycopersici and Their Relationship to Medium Composition and Host-Specific Toxin Production

    Microsoft Academic Search

    CHRISTOPHE MORISSEAU; BARNEY L. WARD; DAVID G. GILCHRIST; BRUCE D. HAMMOCK

    1999-01-01

    The production of Alternaria alternata f. sp. lycopersici host-specific toxins (AAL toxins) and epoxide hydro- lase (EH) activity were studied during the growth of this plant-pathogenic fungus in stationary liquid cultures. Media containing pectin as the primary carbon source displayed peaks of EH activity at day 4 and at day 12. When pectin was replaced by glucose, there was a

  3. Effect of certain inorganic chemicals on growth and spore germination of Alternaria tenuis auct., the fungus causing core rot of mandarin oranges in India

    Microsoft Academic Search

    R. S. SINGIt; R. N. KI-IANNA

    1969-01-01

    Summary Laboratory studies to determine the tolerance of an isolate ofAlternaria tenuis causing a black core rot of mandarin oranges (Citrus reticulata) have shown that presence of low amounts of manganese, zinc, iron, copper, boron, and molybdenum in a synthetic medium stimulated growth and sporulation of the fungus. Concentrations of 20 ppm or more of copper sulphate, boric acid, and

  4. Occurrence of Cladosporium spp. and Alternaria spp. spores in Western, Northern and Central-Eastern Poland in 2004-2006 and relation to some meteorological factors

    NASA Astrophysics Data System (ADS)

    Grinn-Gofro?, Agnieszka; Rapiejko, Piotr

    2009-08-01

    The concentration of airborne spores of Cladosporium spp. and Alternaria spp. has been investigated at three monitoring stations situated along the west-north and central-east transect in Poland (Szczecin, Olsztyn, Warszawa,) i.e. from a height of 100 m to 149 m above sea level. The aerobiological monitoring of fungal spores was performed by means of three Lanzoni volumetric spore traps. Cladosporium spp. spores were dominant at all the stations. The highest Cladosporium spp. and Alternaria spp. numbers of spores were observed at all the cities in July and August. Statistically significant correlations have been found between the Cladosporium spp. and Alternaria spp. concentration in the air and the mean air temperature, amount of precipitation, air pressure and relative air humidity. The spore count of Cladosporium spp. and Alternaria spp. is determined by the diversity of local flora and weather conditions, especially by the air temperature. The identification of factors, which influence and shape spore concentrations, may significantly improve the current methods of allergy prevention.

  5. Functional analyses of the Diels-Alderase gene sol5 of Ascochyta rabiei and Alternaria solani indicate that the Solanapyrone phytotoxins are not required for pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta rabiei and Alternaria solani, the causal agents of Ascochyta blight of chickpea (Cicer arietinum) and early blight of potato (Solanum tuberosum), respectively, produce a set of phytotoxic compounds incuding solanapyrones A, B, and C. Although both the phytotoxicity of solanopyrones and the...

  6. Purification and characterization of an endopolygalacturonase from the rough lemon pathotype of Alternaria alternata, the cause of citrus brown spot disease

    Microsoft Academic Search

    A. Isshiki; K. Akimitsu; K. Nishio; M. Tsukamoto; H. Yamamoto

    1997-01-01

    Alternaria alternatarough lemon pathotype (AC325) produced polygalacturonase in liquid culture containing 1% pectin. Synthesis of the polygalacturonase was repressed by the addition of 5% sucrose to the culture. The enzyme was purified about 31-fold from the filtrates in four steps: ammonium sulphate precipitation; CM-Sepharose; cation exchange HPLC; and gel filtration HPLC. The isolated polygalacturonase acted in an endo fashion: hydrolysis

  7. Laboratory Evaluation of Citrus Cultivars Susceptibility and Influence of Fruit Size on Fortune Mandarin to Infection by Alternaria alternata pv. citri

    Microsoft Academic Search

    A. Vicent; J. Badal; M. J. Asensi; N. Sanz; J. Armengol; J. García-Jiménez

    2004-01-01

    Young leaves of 62 citrus cultivars were inoculated with conidia of three Spanish isolates of Alternaria alternata pv. citri, the causal agent of brown spot of citrus. Hybrids with Dancy mandarin, King mandarin or their derivates as a parent, grapefruit cultivars and the mandarin cultivars Guillermina, Emperor, Clemenpons and Esbal were highly susceptible to the pathogen. Satsuma cultivar Clausellina and

  8. Stem cells, cancer, and cancer stem cells

    Microsoft Academic Search

    Tannishtha Reya; Sean J. Morrison; Michael F. Clarke; Irving L. Weissman

    2001-01-01

    Stem cell biology has come of age. Unequivocal proof that stem cells exist in the haematopoietic system has given way to the prospective isolation of several tissue-specific stem and progenitor cells, the initial delineation of their properties and expressed genetic programmes, and the beginnings of their utility in regenerative medicine. Perhaps the most important and useful property of stem cells

  9. Cell Stem Cell Stem Cell States, Fates,

    E-print Network

    Peterson, Carsten

    and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, Lund SE-223 62, Sweden 4Lund Strategic Research Center for Stem Cell Biology and Cell Therapy, LundCell Stem Cell Review Stem Cell States, Fates, and the Rules of Attraction Tariq Enver,1 Martin

  10. Stemming the Stem Cell Setback

    Microsoft Academic Search

    Patrick J. Fleis

    2003-01-01

    This Comment highlights the recent federal funding setbacks in the biotechnology industry and considers the resulting challenges to future research collaboration. After providing a historical background to stem cell technology, Mr. Fleis examines the passionately opposed public responses to the technology's use of embryos and to its future applications. Fleis continues by noting past legislative initiatives that have accelerated the

  11. Apoptosis: A Functional Paradigm for Programmed Plant Cell Death Induced by a Host-Selective Phytotoxin and Invoked during Development.

    PubMed

    Wang, H.; Li, J.; Bostock, R. M.; Gilchrist, D. G.

    1996-03-01

    The host-selective AAL toxins secreted by Alternaria alternata f sp lycopersici are primary chemical determinants in the Alternaria stem canker disease of tomato. The AAL toxins are members of a new class of sphinganine analog mycotoxins that cause cell death in both animals and plants. Here, we report detection of stereotypic hallmarks of apoptosis during cell death induced by these toxins in tomato. DNA ladders were observed during cell death in toxin-treated tomato protoplasts and leaflets. The intensity of the DNA ladders was enhanced by Ca2+ and inhibited by Zn2+. The progressive delineation of fragmented DNA into distinct bodies, coincident with the appearance of DNA ladders, also was observed during death of toxin-treated tomato protoplasts. In situ analysis of cells dying during development in both onion root caps and tomato leaf tracheary elements revealed DNA fragmentation localized to the dying cells as well as the additional formation of apoptotic-like bodies in sloughing root cap cells. We conclude that the fundamental elements of apoptosis, as characterized in animals, are conserved in plants. The apoptotic process may be expressed during some developmental transitions and is the functional process by which symptomatic lesions are formed in the Alternaria stem canker disease of tomato. Sphinganine analog mycotoxins may be used to characterize further signaling pathways leading to apoptosis in plants. PMID:12239387

  12. Alternaria toxin-induced resistance against rose aphids and olfactory response of aphids to toxin-induced volatiles of rose plants*

    PubMed Central

    Yang, Fa-zhong; Li, Li; Yang, Bin

    2012-01-01

    The search for active toxins for managing weeds or plant diseases is believed to be a promising avenue of investigation. However, the effects of Alternaria toxins on insects have just begun to be investigated. Bioactivities of toxins from four strains of Alternaria alternata on Rosa chinensis and rose aphid Macrosiphum rosivorum were tested in the present study. At a concentration of 50.0 ?g/ml, the crude extract (toxin) of strain 7484 was found not to be harmful to rose plants with excised leaf-puncture method (P?0.079), and rose plants showed enhanced resistance to rose aphids when this Alternaria toxin was sprayed on the plants (P?0.001). However, this toxin caused no detrimental effects on aphids in insecticidal bioassay at a concentration of 10.0 to 160.0 ?g/ml (P?0.096). Therefore, the Alternaria toxin had significantly induced the resistance of rose plants against rose aphids, demonstrating that the resistance mechanism triggered by the Alternaria toxin in the rose plant may also be used by the plant to defend itself against insects. Further bioassays aimed to discover the olfactory responses of aphids to the toxin-induced volatiles of host plants. The aphids were significantly more attracted to both volatiles emitted and collected from control rose plants than to both volatiles emitted and collected from the toxin-treated rose plants (P?0.014). This result showed that the toxin-induced resistance related to the volatile changes of host plants. PMID:22302426

  13. Pseudomonas syringae pv. actinidiae from Recent Outbreaks of Kiwifruit Bacterial Canker Belong to Different Clones That Originated in China

    PubMed Central

    Butler, Margi I.; Stockwell, Peter A.; Black, Michael A.; Day, Robert C.; Lamont, Iain L.; Poulter, Russell T. M.

    2013-01-01

    A recently emerged plant disease, bacterial canker of kiwifruit (Actinidia deliciosa and A. chinensis), is caused by Pseudomonas syringae pv. actinidiae (PSA). The disease was first reported in China and Japan in the 1980s. A severe outbreak of PSA began in Italy in 2008 and has spread to other European countries. PSA was found in both New Zealand and Chile in 2010. To study the evolution of the pathogen and analyse the transmission of PSA between countries, genomes of strains from China and Japan (where the genus Actinidia is endemic), Italy, New Zealand and Chile were sequenced. The genomes of PSA strains are very similar. However, all strains from New Zealand share several single nucleotide polymorphisms (SNPs) that distinguish them from all other PSA strains. Similarly, all the PSA strains from the 2008 Italian outbreak form a distinct clonal group and those from Chile form a third group. In addition to the rare SNPs present in the core genomes, there is abundant genetic diversity in a genomic island that is part of the accessory genome. The island from several Chinese strains is almost identical to the island present in the New Zealand strains. The island from a different Chinese strain is identical to the island present in the strains from the recent Italian outbreak. The Chilean strains of PSA carry a third variant of this island. These genomic islands are integrative conjugative elements (ICEs). Sequencing of these ICEs provides evidence of three recent horizontal transmissions of ICE from other strains of Pseudomonas syringae to PSA. The analyses of the core genome SNPs and the ICEs, combined with disease history, all support the hypothesis of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also originate from China. PMID:23555547

  14. Population structure of Geosmithia morbida, the causal agent of thousand cankers disease of walnut trees in the United States.

    PubMed

    Zerillo, Marcelo M; Ibarra Caballero, Jorge; Woeste, Keith; Graves, Andrew D; Hartel, Colleen; Pscheidt, Jay W; Tonos, Jadelys; Broders, Kirk; Cranshaw, Whitney; Seybold, Steven J; Tisserat, Ned

    2014-01-01

    The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a comprehensive population genetic study of 209 G. morbida isolates collected from Juglans and Pterocarya from 17 geographic regions distributed across 12 U.S. states. The study was based on sequence typing of 27 single nucleotide polymorphisms from three genomic regions and genotyping with ten microsatellite primer pairs. Using multilocus sequence-typing data, 197 G. morbida isolates were placed into one of 57 haplotypes. In some instances, multiple haplotypes were recovered from isolates collected on the same tree. Twenty-four of the haplotypes (42%) were recovered from more than one isolate; the two most frequently occurring haplotypes (H02 and H03) represented 36% of all isolates. These two haplotypes were abundant in California, but were not recovered from Arizona or New Mexico. G. morbida population structure was best explained by four genetically distinct groups that clustered into three geographic regions. Most of the haplotypes isolated from the native range of J. major (Arizona and New Mexico) were found in those states only or present in distinct genetic clusters. There was no evidence of sexual reproduction or genetic recombination in any population. The scattered distribution of the genetic clusters indicated that G. morbida was likely disseminated to different regions at several times and from several sources. The large number of haplotypes observed and the genetic complexity of G. morbida indicate that it evolved in association with at least one Juglans spp. and the walnut twig beetle long before the first reports of the disease. PMID:25393300

  15. Phylogeography of the walnut twig beetle, Pityophthorus juglandis, the vector of thousand cankers disease in North American walnut trees.

    PubMed

    Rugman-Jones, Paul F; Seybold, Steven J; Graves, Andrew D; Stouthamer, Richard

    2015-01-01

    Thousand cankers disease (TCD) of walnut trees (Juglans spp.) results from aggressive feeding in the phloem by the walnut twig beetle (WTB), Pityophthorus juglandis, accompanied by inoculation of its galleries with a pathogenic fungus, Geosmithia morbida. In 1960, WTB was only known from four U.S. counties (in Arizona, California, and New Mexico), but the species has now (2014) invaded over 115 counties, representing much of the western USA, and at least six states in the eastern USA. The eastern expansion places TCD in direct proximity to highly valuable (> $500 billion) native timber stands of eastern black walnut, Juglans nigra. Using mitochondrial DNA sequences, from nearly 1100 individuals, we examined variation among 77 samples of WTB populations across its extended range in the USA, revealing high levels of polymorphism and evidence of two divergent lineages. The highest level of genetic diversity for the different lineages was found in the neighboring Madrean Sky Island and Western New Mexico regions, respectively. Despite their proximity, there was little evidence of mixing between these regions, with only a single migrant detected among 179 beetles tested. Indeed, geographic overlap of the two lineages was only common in parts of Colorado and Utah. Just two haplotypes, from the same lineage, predominated over the vast majority of the recently expanded range. Tests for Wolbachia proved negative suggesting it plays no role in "driving" the spread of particular haplotypes, or in maintaining deep levels of intraspecific divergence in WTB. Genotyping of ribosomal RNA corroborated the mitochondrial lineages, but also revealed evidence of hybridization between them. Hybridization was particularly prevalent in the sympatric areas, also apparent in all invaded areas, but absent from the most haplotype-rich area of each mitochondrial lineage. Hypotheses about the specific status of WTB, its recent expansion, and potential evolutionary origins of TCD are discussed. PMID:25695760

  16. Pseudomonas syringae pv. actinidiae (PSA) Isolates from Recent Bacterial Canker of Kiwifruit Outbreaks Belong to the Same Genetic Lineage

    PubMed Central

    Taratufolo, Maria C.; Cai, Rongman; Almeida, Nalvo F.; Goodman, Tokia; Guttman, David S.; Vinatzer, Boris A.; Balestra, Giorgio M.

    2012-01-01

    Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis) caused by Pseudomonas syringae pv. actinidiae (PSA). The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form of the disease broke out in Italy in 2008 and in additional countries in 2010 and 2011 threatening the viability of the global kiwi fruit industry. To start investigating the source and routes of international transmission of PSA, genomes of strains from China (the country of origin of the genus Actinidia), Japan, Korea, Italy and Portugal have been sequenced. Strains from China, Italy, and Portugal have been found to belong to the same clonal lineage with only 6 single nucleotide polymorphisms (SNPs) in 3,453,192 bp and one genomic island distinguishing the Chinese strains from the European strains. Not more than two SNPs distinguish each of the Italian and Portuguese strains from each other. The Japanese and Korean strains belong to a separate genetic lineage as previously reported. Analysis of additional European isolates and of New Zealand isolates exploiting genome-derived markers showed that these strains belong to the same lineage as the Italian and Chinese strains. Interestingly, the analyzed New Zealand strains are identical to European strains at the tested SNP loci but test positive for the genomic island present in the sequenced Chinese strains and negative for the genomic island present in the European strains. Results are interpreted in regard to the possible direction of movement of the pathogen between countries and suggest a possible Chinese origin of the European and New Zealand outbreaks. PMID:22590555

  17. Education research Making STEM

    E-print Network

    Rambaut, Andrew

    Education research Working Together: Making STEM happen in secondary schools #12;STEM education | 1 The Camden School STEM Initiative Interdisciplinary STEM education stimulates interest in science, technology on the combined application of all four subjects. Students of Maria Fidelis consider how to use their STEM garden

  18. The anthraquinone derivatives from the fungus Alternaria sp. XZSBG-1 from the saline lake in Bange, Tibet, China.

    PubMed

    Chen, Bin; Shen, Qiong; Zhu, Xun; Lin, Yongcheng

    2014-01-01

    Four new anthraquinone derivatives 1-4 were obtained along with seven known compounds 5-11 from the extracts of the fungal strain Alternaria sp. XZSBG-1 which was isolated from the sediments of the carbonate saline lake in Bange, Tibet, China. Their structures were determined by spectroscopic methods, mainly by 2D NMR spectra. Compound 1 is a novel tetrahydroanthraquinone with an epoxy ether bond between C-4a and C-9a. In the primary bioassays, compound 3 (alterporriol T) exhibited inhibition of a-glucosidase with a IC50 value 7.2 ?M, and compound 9 showed good inhibitory activity against the HCT-116 and HeLa cell lines, with IC50 values of 3.03 and 8.09 ?M, respectively. PMID:25317580

  19. Spatial and temporal distribution of Alternaria spores in the Iberian Peninsula atmosphere, and meteorological relationships: 1993-2009

    NASA Astrophysics Data System (ADS)

    Aira, María-Jesús; Rodríguez-Rajo, Francisco-Javier; Fernández-González, María; Seijo, Carmen; Elvira-Rendueles, Belén; Abreu, Ilda; Gutiérrez-Bustillo, Montserrat; Pérez-Sánchez, Elena; Oliveira, Manuela; Recio, Marta; Tormo, Rafael; Morales, Julia

    2013-03-01

    This paper provides an updated of airborne Alternaria spore spatial and temporal distribution patterns in the Iberian Peninsula, using a common non-viable volumetric sampling method. The highest mean annual spore counts were recorded in Sevilla (39,418 spores), Mérida (33,744) and Málaga (12,947), while other sampling stations never exceeded 5,000. The same cities also recorded the highest mean daily spore counts (Sevilla 109 spores m-3; Mérida 53 spores m-3 and Málaga 35 spores m-3) and the highest number of days on which counts exceeded the threshold levels required to trigger allergy symptoms (Sevilla 38 % and Mérida 30 % of days). Analysis of annual spore distribution patterns revealed either one or two peaks, depending on the location and prevailing climate of sampling stations. For all stations, average temperature was the weather parameter displaying the strongest positive correlation with airborne spore counts, whilst negative correlations were found for rainfall and relative humidity.

  20. Alterporriol-Type Dimers from the Mangrove Endophytic Fungus, Alternaria sp. (SK11), and Their MptpB Inhibitions

    PubMed Central

    Xia, Guoping; Li, Jia; Li, Hanxiang; Long, Yuhua; Lin, Shao’e; Lu, Yongjun; He, Lei; Lin, Yongcheng; Liu, Lan; She, Zhigang

    2014-01-01

    A new alterporriol-type anthranoid dimer, alterporriol S (1), along with seven known anthraquinone derivatives, (+)-aS-alterporriol C (2), hydroxybostrycin (3), halorosellinia A (4), tetrahydrobostrycin (5), 9?-hydroxydihydrodesoxybostrycin (6), austrocortinin (7) and 6-methylquinizarin (8), were isolated from the culture broth of the mangrove fungus, Alternaria sp. (SK11), from the South China Sea. Their structures and the relative configurations were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR spectra. The absolute configurations of 1 and the axial configuration of 2 were defined by experimental and theoretical ECD spectroscopy. 1 was identified as the first member of alterporriols consisting of a unique C-10?C-2? linkage. Atropisomer 2 exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with an IC50 value 8.70 ?M. PMID:24840716

  1. Seven naphtho-?-pyrones from the marine-derived fungus Alternaria alternata: structure elucidation and biological properties

    PubMed Central

    2012-01-01

    Eight bioactive pyrone derivatives were identified from the culture of Alternaria alternata strain D2006, isolated from the marine soft coral Denderonephthya hemprichi, which was selected as its profound antimicrobial activities. The compounds were assigned as pyrophen (1), rubrofusarin B (2), fonsecin (3), and fonsecin B (5) beside to the four dimeric naphtho-?-pyrones; aurasperone A (6), aurasperone B (7), aurasperone C (8), and aurasperone F (9). Structures of the isolated compounds were identified on the basis of 1D and 2D NMR spectroscopy and mass (EI, ESI, HRESI) data, and by comparison with the literature. Configuration of the four dimeric naphtho-?-pyrones 6-9 was analyzed by CD spectra, exhibiting an identical stereochemistry. PMID:22377027

  2. Stem cell niches

    Microsoft Academic Search

    V. V. Terskikh; A. V. Vasiliev; E. A. Vorotelyak

    2007-01-01

    The nature of the stem cell niche and its interaction with stem cells is one of fundamental problems in the biology of stem\\u000a cells. Stem cell niches are formed during ontogeny. A niche can remain vacant and exist independently of stem cells; however,\\u000a stem cell self-renewal cannot be maintained for long periods outside of the niche except for particular conditions,

  3. Thinkfinity: STEM

    NSDL National Science Digital Library

    The Verizon Foundation's Thinkfinity website has a very large section of STEM resources for students and teachers. Near the bottom of the homepage visitors will find "Lesson Plans", "Podcasts", and "Resources and Tools". In addition, there is a community forum where members discuss their thoughts on some of the resources from the website they have found useful, or how they have modified them to suit their classroom situation. Visitors to the site can easily register for free to join the community. The "At Home and Afterschool" tab near the top of the page has a "games and tools" section that includes activities, videos, and collections, as well as other types of resources. The literacy section of the "Afterschool" area has many resources for families and games for early literacy. Visitors can also use the "Professional Development" tab to find information on how to utilize the many Thinkfinity resources.

  4. Stable integration and expression of wasabi defensin gene in “Egusi” melon ( Colocynthis citrullus L.) confers resistance to Fusarium wilt and Alternaria leaf spot

    Microsoft Academic Search

    Valentine Otang Ntui; Gunaratnam Thirukkumaran; Pejman Azadi; Raham Sher Khan; Ikuo Nakamura; Masahiro Mii

    2010-01-01

    Production of “Egusi” melon (Colocynthis citrullus L.) in West Africa is limited by fungal diseases, such as Alternaria leaf spot and Fusarium wilt. In order to engineer “Egusi”\\u000a resistant to these diseases, cotyledonary explants of two “Egusi” genotypes, ‘Ejagham’ and NHC1-130, were transformed with\\u000a Agrobacterium tumefaciens strain EHA101 harbouring wasabi defensin gene (isolated from Wasabia japonica L.) in a binary

  5. An Isolate of Alternaria alternata That Is Pathogenic to Both Tangerines and Rough Lemon and Produces Two Host-Selective Toxins, ACT- and ACR-Toxins.

    PubMed

    Masunaka, A; Ohtani, K; Peever, T L; Timmer, L W; Tsuge, T; Yamamoto, M; Yamamoto, H; Akimitsu, K

    2005-03-01

    ABSTRACT Two different pathotypes of Alternaria alternata cause Alternaria brown spot of tangerines and Alternaria leaf spot of rough lemon. The former produces the host-selective ACT-toxin and the latter produces ACR-toxin. Both pathogens induce similar symptoms on leaves or young fruits of their respective hosts, but the host ranges of these pathogens are distinct and one pathogen can be easily distinguished from another by comparing host ranges. We isolated strain BC3-5-1-OS2A from a leaf spot on rough lemon in Florida, and this isolate is pathogenic on both cv. Iyokan tangor and rough lemon and also produces both ACT-toxin and ACR-toxin. Isolate BC3-5-1-OS2A carries both genomic regions, one of which was known only to be present in ACT-toxin producers and the other was known to exist only in ACR-toxin producers. Each of the genomic regions is present on distinct small chromosomes, one of 1.05 Mb and the other of 2.0 Mb. Alternaria species have no known sexual or parasexual cycle in nature and populations of A. alternata on citrus are clonal. Therefore, the ability to produce both toxins was not likely acquired through meiotic or mitotic recombination. We hypothesize that a dispensable chromosome carrying the gene cluster controlling biosynthesis of one of the host-selective toxins was transferred horizontally and rearranged by duplication or translocation in another isolate of the fungus carrying genes for biosynthesis of the other host-selective toxin. PMID:18943116

  6. Production of plants resistant to Alternaria carthami via organogenesis and somatic embryogenesis of safflower cv. NARI-6 treated with fungal culture filtrates

    Microsoft Academic Search

    J. Vijaya Kumar; B. D. Ranjitha Kumari; G. Sujatha; Enrique Castaño

    2008-01-01

    The present study describes a system for efficient plant regeneration via organogenesis and somatic embryogenesis of safflower\\u000a (Carthamus\\u000a tinctorius L.) cv. NARI-6 in fungal culture filtrates (FCF)-treated cultures. FCF was prepared by culturing Alternaria carthami fungal mycelia in selection medium for host-specific toxin production. Cotyledon explants cultured on callus induction medium\\u000a with different levels of FCF (10–50%) produced embryogenic callus.

  7. Epidermal Stem Cells

    Microsoft Academic Search

    V. V. Terskikh; A. V. Vasil'ev

    2001-01-01

    Epidermis contains a compartment of stem cells but currently there is no common criterion to recognize individual stem cells with any confidence. Epidermis appears to contain stem cells of different levels of maturity and it is very likely that the main repository of epidermal stem cells is located in the hair follicle from which cells can emigrate into epidermis and

  8. Rotatable stem and lock

    DOEpatents

    Deveney, Joseph E. (Albuquerque, NM); Sanderson, Stephen N. (Albuquerque, NM)

    1984-01-01

    A valve stem and lock include a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

  9. Rotatable stem and lock

    DOEpatents

    Deveney, J.E.; Sanderson, S.N.

    1981-10-27

    A valve stem and lock is disclosed which includes a housing surrounding a valve stem, a solenoid affixed to an interior wall of the housing, an armature affixed to the valve stem and a locking device for coupling the armature to the housing body. When the solenoid is energized, the solenoid moves away from the housing body, permitting rotation of the valve stem.

  10. Stem cells in urology

    Microsoft Academic Search

    Tamer Aboushwareb; Anthony Atala

    2008-01-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem

  11. Toward ‘SMART’ stem cells

    Microsoft Academic Search

    T Cheng

    2008-01-01

    Stem cell research is at the heart of regenerative medicine, which holds great promise for the treatment of many devastating disorders. However, in addition to hurdles posed by well-publicized ethical issues, this emerging field presents many biological challenges. What is a stem cell? How are embryonic stem cells different from adult stem cells? What are the physiological bases for therapeutically

  12. Stem Cell 101 What is a stem cell?

    E-print Network

    Minnesota, University of

    Stem Cell 101 What is a stem cell? A stem cell is a parent cell in the body that has two specific into all types of tissue in the body ­ this is called differentiation. Where are stem cells found? There are two types of stem cells: embryonic stem cells, found in embryos, and adult stem cells, which can

  13. Functional analysis of a multicopy host-selective ACT-toxin biosynthesis gene in the tangerine pathotype of Alternaria alternata using RNA silencing.

    PubMed

    Miyamoto, Y; Masunaka, A; Tsuge, T; Yamamoto, M; Ohtani, K; Fukumoto, T; Gomi, K; Peever, T L; Akimitsu, K

    2008-12-01

    Alternaria brown spot, caused by the tangerine pathotype of Alternaria alternata, is a serious disease of commercially important tangerines and their hybrids. The pathogen produces host-selective ACT toxin, and several genes (named ACTT) responsible for ACT-toxin biosynthesis have been identified. These genes have many paralogs, which are clustered on a small, conditionally dispensable chromosome, making it difficult to disrupt entire functional copies of ACTT genes using homologous recombination-mediated gene disruption. To overcome this problem, we attempted to use RNA silencing, which has never been employed in Alternaria spp., to knock down the functional copies of one ACTT gene with a single silencing event. ACTT2, which encodes a putative hydrolase and is present in multiple copies in the genome, was silenced by transforming the fungus with a plasmid construct expressing hairpin ACTT2 RNAs. The ACTT2 RNA-silenced transformant (S-7-24-2) completely lost ACTT2 transcripts and ACT-toxin production as well as pathogenicity. These results indicated that RNA silencing may be a useful technique for studying the role of ACTT genes responsible for host-selective toxin biosynthesis in A. alternata. Further, this technique may be broadly applicable to the analysis of many genes present in multiple copies in fungal genomes that are difficult to analyze using recombination-mediated knockdowns. PMID:18986255

  14. Comparative study on the effect of chemicals on Alternaria blight in Indian mustard--a multi-location study in India.

    PubMed

    Meena, P D; Chattopadhyay, C; Kumar, A; Awasthi, R P; Singh, R; Kaur, S; Thomas, L; Goyal, P; Chand, P

    2011-05-01

    High severity of Altemaria blight disease is a major constraint in production of rapeseed-mustard in India. The aim of this study was to investigate the suppressive potential of chemicals viz., zinc sulphate, borax, sulphur, potash and calcium sulphate, aqueous extracts viz., Eucalyptus globosus (50 g l-1) leaf extract and garlic (Allium sativum) bulb (20 g l-1) extract, cow urine and bio-agents Trichoderma harzianum, Pseudomonas fluorescence in comparison with the recommended chemical fungicide (mancozeb), against foliar disease Alternaria blight of Indian mustard [Brassica juncea (L.) Czern. and Coss] under five different geographical locations of India. Mancozeb recorded the lowest mean severity (leaf: 33.1%; pod: 26.3%) of Alternaria blight with efficacy of garlic bulb extract alone (leaf = 34.4%; pod = 27.3%) or in combination with cow urine (leaf = 34.2%; pod = 28.6%) being statistically at par with the recommended chemical fungicide. Chemicals also proved effective in reducing Alternaria blight severity on leaves and pods of Indian mustard (leaf = 36.3-37.9%; pod = 27.5-30.1%). The effective treatments besides providing significant reduction in disease severity also enabled increase in dry seed yield of the crop (mancozeb = 2052 kg ha-1; garlic = 2006 kg ha-1; control = 1561 kg ha-1). PMID:22167952

  15. The LOV Protein of Xanthomonas citri subsp. citri Plays a Significant Role in the Counteraction of Plant Immune Responses during Citrus Canker

    PubMed Central

    Kraiselburd, Ivana; Daurelio, Lucas D.; Tondo, María Laura; Merelo, Paz; Cortadi, Adriana A.; Talón, Manuel; Tadeo, Francisco R.; Orellano, Elena G.

    2013-01-01

    Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. The ability of this bacterium to colonize host plants is influenced by bacterial blue-light sensing through a LOV-domain protein and disease symptoms are considerably altered upon deletion of this protein. In this work we aimed to unravel the role of this photoreceptor during the bacterial counteraction of plant immune responses leading to citrus canker development. We performed a transcriptomic analysis in Citrus sinensis leaves inoculated with the wild type X. citri subsp. citri and with a mutant strain lacking the LOV protein by a cDNA microarray and evaluated the differentially regulated genes corresponding to specific biological processes. A down-regulation of photosynthesis-related genes (together with a corresponding decrease in photosynthesis rates) was observed upon bacterial infection, this effect being more pronounced in plants infected with the lov-mutant bacterial strain. Infection with this strain was also accompanied with the up-regulation of several secondary metabolism- and defense response-related genes. Moreover, we found that relevant plant physiological alterations triggered by pathogen attack such as cell wall fortification and tissue disruption were amplified during the lov-mutant strain infection. These results suggest the participation of the LOV-domain protein from X. citri subsp. citri in the bacterial counteraction of host plant defense response, contributing in this way to disease development. PMID:24260514

  16. Quantitative association of bark beetles with pitch canker fungus and effects of verbenone on their semiochemical communication in Monterey pine forests in Northern Spain.

    PubMed

    Romón, Pedro; Iturrondobeitia, Juan Carlos; Gibson, Ken; Lindgren, B Staffan; Goldarazena, Arturo

    2007-08-01

    The association between 11 species of bark beetles (Coleoptera: Scolytinae) and one weevil (Coleoptera: Entiminae) with the pitch canker fungus, Fusarium circinatum Nirenberg and O'Donnell, was determined by crushing beetles on selective medium and histone H3 gene sequencing. Pityophthorus pubescens (Marsham) (25.00%), Hylurgops palliatus (Gyllenhal) (11.96%), Ips sexdentatus (Börner) (8.57%), Hypothenemus eruditus Westwood (7.89%), Hylastes attenuatus Erichson (7.40%), and Orthotomicus erosus (Wollaston) (2.73%) were found to carry the inoculum. In addition, the root weevil Brachyderes incanus L. (14.28%) had the second highest frequency of occurrence of the fungus. The responses of the insects to a range of verbenone doses were tested in field bioassays using funnel traps. Catches of P. pubescens, a species colonizing branch tips of live trees, were significantly reduced in a log-linear dose-dependent relationship. Catches of I. sexdentatus, an opportunistic species normally attacking fresh dead host material, were also gradually reduced with increasing verbenone dose. Catches of Tomicus piniperda L., O. erosus, Dryocoetes autographus (Ratzeburg), H. eruditus, Xyleborus dryographus (Ratzeburg), Hylastes ater (Paykull), Hylurgus ligniperda (F.), H. attenuatus, and B. incanus were not significantly affected by verbenone. The effects of verbenone were consistent with differences in host-age preference. Semiochemical disruption by verbenone in P. pubescens and I. sexdentatus could represent an integrated pest management strategy for the prevention of the spread of pitch canker disease between different stands. However, several species associated with F. circinatum were unaffected by verbenone, not supporting this compound for prevention of the establishment of potential vectors in Northern Spain. PMID:17716465

  17. Circular DNA Plasmid in the Phytopathogenic Fungus Alternaria Alternata: Its Temperature-Dependent Curing and Association with Pathogenicity

    PubMed Central

    Katsuya, S.; Kaneko, I.; Owaki, M.; Ishikawa, K.; Tsujimoto, T.; Tsuge, T.

    1997-01-01

    We found the presence of plasmid DNA in strain T88-56 of the Japanese pear pathotype of Alternaria alternata, which causes black spot of certain cultivars of Japanese pear by producing host-specific AK-toxin. The plasmid, designated pAAT56, was identified to be an ~5.4-kilobase (kb) circular molecule by electron microscopic observation and restriction endonuclease mapping. Southern blot analysis showed that pAAT56 DNA had no homology with either nuclear or mitochondrial DNA. Cultures of strain T88-56 grown at 26° showed markedly reduced plasmid levels relative to those grown at lower temperatures. The strain was completely cured of pAAT56 during growth at 29°. Temperature-dependent curing of pAAT56 was confirmed by using single-protoplast isolates from mycelia grown at 23°, most of which maintained the plasmid, and from mycelia grown at 29°, most of which had lost the plasmid. Northern blot analysis detected the presence of three RNA species (~1.7, 2.7 and 5.4 kb) transcribed from pAAT56. The biological function of pAAT56 was observed using single-protoplast isolates from mycelia that either contained or had been cured of pAAT56. The plasmid-containing isolates tended to be reduced in AK-toxin production and pathogenicity compared with the plasmid-cured isolates. PMID:9136005

  18. Induction of resistance in host against the infection of leaf blight pathogen (Alternaria palandui) in onion (Allium cepa var aggregatum).

    PubMed

    Karthikeyan, M; Jayakumar, V; Radhika, K; Bhaskaran, R; Velazhahan, R; Alice, D

    2005-12-01

    The Pseudomonas fluorescens isolate Pfl was found to inhibit the growth of pathogen Alternaria palandui, in vitro. In the present study, foliar application of a talc-based formulation of Pfl significantly reduced the incidence of leaf blight of onion, caused by A. palandui. Induction of defense-related proteins viz., chitinase, beta-1,3 glucanase, peroxidase (PO) and polyphenol oxidase (PPO) by application of Pfl, was studied against A. palandui infection in resistant (IHR 56) and susceptible (MDUI) onion cultivars. Chitinase in both cultivars, with or without challenge-inoculation of A. palandui revealed changes in the isoform pattern. The Native-PAGE of PO showed induction of PO2 isoform in both the cultivars, in response to inoculation of pathogen. Isoform analysis of PPO also exhibited induction in the Pfl-treated plants challenged with pathogen. Similarly, the activity of beta-1,3-glucanase was greatly induced in Pfl-treated plants, challenged with pathogen as compared to controls. Thus, the P. fluorescens-treated plants showed significant increase in the levels of the defense enzymes, in comparison to the plants challenged with the pathogen. PMID:16955738

  19. Functional analysis of the promoter of a glycosyl hydrolase gene induced in resistant Sinapis alba by Alternaria brassicicola.

    PubMed

    Chatterjee, Madhuvanti; Mazumder, Mrinmoy; Basu, Debabrata

    2013-08-01

    A putative family 3 glycosyl hydrolase (GH) gene showed significant differential expression in resistant Sinapis alba, compared with the susceptible Brassica juncea, as part of the initial responses during interaction with the necrotroph Alternaria brassicicola. To understand the mechanism of induction, the promoter was isolated and deletion analysis carried out. All the promoter fragments were fused with the ?-glucuronidase gene and the expressions were studied in stable B. juncea transgenics and transiently transformed Nicotiana tabacum. Analysis of the expression of the promoter showed the presence of functional abscisic acid (ABA)-, jasmonic acid (JA)-, and salicylic acid (SA)-responsive cis elements. Interestingly, the promoter was found to be induced in both S. alba and B. juncea upon challenge with A. brassicicola but, in S. alba, SA had an inhibitory effect on the pathogen-induced expression of the gene whereas, in B. juncea, SA did not have any negative effect. Therefore, the SA-mediated inhibition in S. alba indicates that the induction is probably through JA or ABA signaling. The difference in the mechanism of induction of the same promoter in the resistant and susceptible plants is probably due to the differential hormonal responses initiated upon challenge with A. brassicicola. PMID:23550974

  20. Effect of gamma irradiation and water activity on mycotoxin production of Alternaria in tomato paste and juice.

    PubMed

    Aziz, N H; Farag, S; Hassanin, M A

    1991-01-01

    Gamma-irradiation, water activity (aw) and incubation temperature were found to affect the production of tenuazonic acid (TZA) by Alternaria alternata in tomato paste and juice. By increasing the irradiation doses, the dry weight as well as TZA decreased greatly until complete inhibition at 4 kGy. Greatest production of TZA occurred at 0.98 aw (57.5 micrograms/g and 26.3 micrograms/g) for both tomato paste and juice, respectively, at 25 degrees C. Changing temperature and aw altered the relative amounts of TZA produced in tomato paste und juice by unirradiated and irradiated conidia of A. alternata. Only trace amount of TZA was detected at 0.98 aw (1.50 micrograms/g) by 3 kGy-irradiated conidia in tomato paste, while it was inhibited completely in juice. Increasing gamma-irradiation doses and decreasing water activities decreased greatly or inhibited TZA production in both tomato paste and juice. PMID:1922270

  1. Selection and differentiation of Bacillus spp. Antagonistic to Fusarium oxysporum f.sp. lycopersici and Alternaria solani infecting Tomato.

    PubMed

    Shanmugam, Veerubommu; Atri, Kamini; Gupta, Samriti; Kanoujia, Nandina; Naruka, Digvijay Singh

    2011-03-01

    Antagonistic Bacillus spp. displaying in vitro production of siderophore, chitinase, and ?-1,3-glucanase were identified from dual culture assays. In independent greenhouse studies, seed bacterization and soil application of Bacillus atrophaeus S2BC-2 challenge inoculated with Fusarium oxysporum f.sp. lycopersici (FOL) and Alternaria solani (AS) recorded low percent disease index of 25.3 and 28.7, respectively, over nonbacterised pathogen control (44.3 and 56.4). The low disease incidence corroborated with tomato growth promotion with high vigor index (8,041.2) and fresh plant weight (82.5 g) on challenge inoculation with FOL. Analysis of root and leaf samples in rhizobacterial treatment challenged with FOL and AS revealed maximum induction of chitinase (1.9 and 1.7 U/mg of protein, respectively) and ?-1,3-glucanase (23.5 and 19.2 U/mg of protein, respectively). In native gel activity assays, the rhizobacterial treatment on challenge inoculation strongly expressed three high intensity PO isoforms along with one low intensity isoform. In studies on genetic diversity of the Bacillus strains by repetitive extragenomic palindromic-polymerase chain reaction (REP-PCR) and amplified rDNA restriction analysis (ARDRA) patterns, ARDRA was more highly discriminant than REP-PCR and allowed grouping of the strains and differentiation of the antagonistic strains from other isolates. PMID:21503737

  2. The phytoalexin camalexin induces fundamental changes in the proteome of Alternaria brassicicola different from those caused by brassinin.

    PubMed

    Pedras, M Soledade C; Minic, Zoran; Abdoli, Abbas

    2014-01-01

    Camalexin is the major phytoalexin produced by Alternaria thaliana, but is absent in Brassica species that usually produce phytoalexin blends containing brassinin and derivatives. The protein profiles of A. brassicicola treated with camalexin were evaluated using proteomics and metabolic analyses and compared with those treated with brassinin. Conidial germination and mycelial growth of A. brassicicola in liquid media amended with camalexin and brassinin showed that fungal growth was substantially slower in presence of camalexin than brassinin; chemical analyses revealed that A. brassicicola detoxified camalexin at much slower rate than brassinin. Two-dimensional gel electrophoresis (2-DE) followed by tryptic digestion and capillary liquid chromatography-mass spectrometric analyses identified 158 different proteins, of which 45 were up-regulated and 113 were down-regulated relative to controls. Venn diagram analyses of differentially expressed proteins in cultures of A. brassicicola incubated with camalexin and brassinin indicated clear differences in the effect of each phytoalexin, with camalexin causing down-regulation of a larger number of proteins than brassinin. Overall, results of this work suggest that each phytoalexin has several different targets in the cells of A. brassicicola, and that camalexin appears to have greater potential to protect cultivated Brassica species against A. brassicicola than brassinin. PMID:24433679

  3. Cyclic AMP-dependent protein kinase A negatively regulates conidia formation by the tangerine pathotype of Alternaria alternata.

    PubMed

    Tsai, Hsieh-Chin; Yang, Siwy Ling; Chung, Kuang-Ren

    2013-02-01

    The necrotrophic fungal pathogen Alternaria alternata causes brown spot diseases in many citrus cultivars. The FUS3 and SLT2 mitogen-activated protein kinases (MAPK)-mediated signaling pathways have been shown to be required for conidiation. Exogenous application of cAMP to this fungal pathogen decreased conidia formation considerably. This study determined whether a cAMP-activated protein kinase A (PKA) is required for conidiation. Using loss-of-function mutations in PKA catalytic and regulatory subunit-coding genes, we demonstrated that PKA negatively regulates conidiation. Fungal mutants lacking PKA catalytic subunit gene (PKA ( cat )) reduced growth, lacked detectable PKA activity, and produced higher amounts of conidia compared to wild-type. Introduction of a functional copy of PKA ( cat ) into a null mutant partially restored PKA activity and produced wild-type level of conidia. In contrast, fungi lacking PKA regulatory subunit gene (PKA ( reg )) produced detectable PKA activity, exhibited severe growth reduction, formed swelling hyphal segments, and produced no mature conidia. Introduction of the PKA ( reg ) gene to a regulatory subunit mutant restored all phenotypes to wild type. PKA ( reg )-null mutants induced fewer necrotic lesions on citrus compared to wild-type, whereas PKA ( cat ) mutant displayed wild-type virulence. Overall, our studies indicate that PKA and FUS3-mediated signaling pathways apparently have very different roles in the regulation of conidia production and A. alternata pathogenesis in citrus. PMID:23054702

  4. Dehydrin-like Proteins in the Necrotrophic Fungus Alternaria brassicicola Have a Role in Plant Pathogenesis and Stress Response

    PubMed Central

    Pochon, Stéphanie; Simoneau, Philippe; Pigné, Sandrine; Balidas, Samuel; Bataillé-Simoneau, Nelly; Campion, Claire; Jaspard, Emmanuel; Calmes, Benoît; Hamon, Bruno; Berruyer, Romain; Juchaux, Marjorie; Guillemette, Thomas

    2013-01-01

    In this study, the roles of fungal dehydrin-like proteins in pathogenicity and protection against environmental stresses were investigated in the necrotrophic seed-borne fungus Alternaria brassicicola. Three proteins (called AbDhn1, AbDhn2 and AbDhn3), harbouring the asparagine-proline-arginine (DPR) signature pattern and sharing the characteristic features of fungal dehydrin-like proteins, were identified in the A. brassicicola genome. The expression of these genes was induced in response to various stresses and found to be regulated by the AbHog1 mitogen-activated protein kinase (MAPK) pathway. A knock-out approach showed that dehydrin-like proteins have an impact mainly on oxidative stress tolerance and on conidial survival upon exposure to high and freezing temperatures. The subcellular localization revealed that AbDhn1 and AbDhn2 were associated with peroxisomes, which is consistent with a possible perturbation of protective mechanisms to counteract oxidative stress and maintain the redox balance in AbDhn mutants. Finally, we show that the double deletion mutant ??abdhn1-abdhn2 was highly compromised in its pathogenicity. By comparison to the wild-type, this mutant exhibited lower aggressiveness on B. oleracea leaves and a reduced capacity to be transmitted to Arabidopsis seeds via siliques. The double mutant was also affected with respect to conidiation, another crucial step in the epidemiology of the disease. PMID:24098369

  5. Canker Sores: Treatment

    MedlinePLUS

    ... RAS fall roughly into four categories: occlusives, anesthetics, cleansing agents / antiseptics, and other. OTC products often combine ... with hypersensitivity. Many OTC anesthetic products are available. Cleansing agents/ Antiseptics can cleanse the area and decrease ...

  6. OPT STEM EXTENSION APPLICATION What is the OPT STEM Extension?

    E-print Network

    OPT STEM EXTENSION APPLICATION What is the OPT STEM Extension? The OPT STEM Extension is a 17-month based on a bachelor's, master's, or Ph.D in certain STEM (Science, Technology, Engineering, Math) fields. Who is Eligible for the OPT STEM Extension? F-1 students who: 1). hold a STEM degree (see pg. 2

  7. UW Summer STEM Undergraduate

    E-print Network

    Kaminsky, Werner

    UW Summer STEM Undergraduate Research Poster SessionWednesday, August 21st, 2013 9:00 am--12 noon to conduct research in STEM fields. For more information, contact the Undergraduate Research Program at: urp

  8. Choosing a STEM Career

    NSDL National Science Digital Library

    2009-11-10

    Students will view video clips about graduate and middle school students with interests in STEM careers and compare technologies from yesterday with today. They will explore careers on-line before writing about their futures as STEM professionals.

  9. Stem Cell Information: Glossary

    MedlinePLUS

    ... medicine Reproductive cloning Signals Somatic cell Somatic cell nuclear transfer (SCNT) Somatic (adult) stem cell Stem cells ... refer to an animal produced by somatic cell nuclear transfer (SCNT) or parthenogenesis . Cloning —See Clone . Cord ...

  10. Umbilical Cord Stem Cells

    Microsoft Academic Search

    Kathy E. Mitchell

    The two most basic properties of stem cells are the capacities to self-renew and to differentiate into multiple cell or tissue\\u000a types (1–3). Generally, stem cells are categorized as one of three types: embryonic stem cells (ES), embryonic germ cells (EG), or adult\\u000a stem cells. ES cells are derived from the inner cell mass of the blastula (Fig. 1). They

  11. STEM Bridge Scholarship Program

    E-print Network

    Buehrer, R. Michael

    2015-2016 STEM Bridge Scholarship Program Virginia Space Grant Consortium (VSGC) provides renewable STEM Bridge Scholarships of $1,000 to sophomore students from any federally recognized minority group enrolled full-time in a program of study in science, technology, engineering, or math (STEM) at one

  12. Understanding Embryonic Stem Cells

    NSDL National Science Digital Library

    Douglas A. Melton, Ph.D. (Howard Hughes Medical Institute; )

    2008-04-10

    This indexed webcast video along with synchronized lecture slides is from Howard Hughes Medical Institute's 2006 Holiday LecturesPotent Biology: Stem Cells, Cloning, and Regeneration. Douglas A. Melton presents an introduction to stem cells, as well as answers to questions about the role of stem cells in the human body. This video requires RealPlayer 10.

  13. Understanding STEM: Current Perceptions

    ERIC Educational Resources Information Center

    Brown, Ryan; Brown, Joshua; Reardon, Kristin; Merrill, Chris

    2011-01-01

    In many ways, the push for STEM (science, technology, engineering, and mathematics) education appears to have grown from a concern for the low number of future professionals to fill STEM jobs and careers and economic and educational competitiveness. The proponents of STEM education believe that by increasing math and science requirements in…

  14. Chestnut Blight (Cryphonectria parasitica)

    E-print Network

    for the pathogen. Basal lesion with outer bark removed showing dying inner bark. Death of the main stem may occur. Cankering and bark splitting at the base of a young tree symptomatic of bark death. Heavily cankered stem

  15. Stem Cell Quick Guide: Stem Cell Basics What is a Stem Cell?

    E-print Network

    Schladow, S. Geoffrey

    Stem Cell Quick Guide: Stem Cell Basics What is a Stem Cell? Stem cells are the starting point from to line blood vessels. All of these highly specialized cells have to grow from unspecialized stem cells. Stem cells produce new cells by dividing. In the right conditions, these new cells can then continue

  16. Minor contribution of alternariol, alternariol monomethyl ether and tenuazonic acid to the genotoxic properties of extracts from Alternaria alternata infested rice.

    PubMed

    Schwarz, Christoph; Kreutzer, Martin; Marko, Doris

    2012-10-01

    Alternaria spp. are known to form a spectrum of secondary metabolites with alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT) and tenuazonic acid (TA) as the major mycotoxins with respect to quantity. In the present study we investigated the contribution of these compounds for the DNA damaging properties of complex extracts of Alternaria spp. infested rice. Five different Alternaria strains were cultured on rice and analyzed for their production of AOH, AME, ALT and TA. The extracts of two strains with distinctly different toxin profiles were selected for further toxicological analysis. An extract from A. alternata DSM 1102 infested rice, found to contain predominantly TA, exhibited substantial DNA strand breaking properties in cultured human colon carcinoma cells in the comet assay, whereas TA as a single compound did not affect DNA integrity up to 200?M. An extract of A. alternata DSM 12633 infested rice, containing in comparable proportions AOH, AME and TA, exceeded by far the DNA damaging properties of the single compounds. In contrast to AOH, AME and TA, both selected extracts induced an increase of DNA modifications sensitive to the bacterial repair enzyme formamidopyrimidine DNA glycosylase (FPG) in the comet assay, indicative for oxidative DNA damage. Toxicity-guided fractionation of the DSM 12633 extract confirmed that these effects were not caused by AOH, AME or TA. Taken together, the mycotoxins AOH, AME and TA, representing the major mycotoxins with respect to quantity in A. alternata infested food, play only a subordinate role for the genotoxic properties of complex extracts and appear not to be involved in the induction of FPG sensitive sites. PMID:22906495

  17. Stable integration and expression of wasabi defensin gene in "Egusi" melon (Colocynthis citrullus L.) confers resistance to Fusarium wilt and Alternaria leaf spot.

    PubMed

    Ntui, Valentine Otang; Thirukkumaran, Gunaratnam; Azadi, Pejman; Khan, Raham Sher; Nakamura, Ikuo; Mii, Masahiro

    2010-09-01

    Production of "Egusi" melon (Colocynthis citrullus L.) in West Africa is limited by fungal diseases, such as Alternaria leaf spot and Fusarium wilt. In order to engineer "Egusi" resistant to these diseases, cotyledonary explants of two "Egusi" genotypes, 'Ejagham' and NHC1-130, were transformed with Agrobacterium tumefaciens strain EHA101 harbouring wasabi defensin gene (isolated from Wasabia japonica L.) in a binary vector pEKH1. After co-cultivation for 3 days, infected explants were transferred to MS medium containing 100 mg l(-l) kanamycin to select transformed tissues. After 3 weeks of culture, adventitious shoots appeared directly along the edges of the explants. As much as 19 out of 52 (36.5%) and 25 out of 71 (35.2%) of the explants in genotype NHC1-130 and 'Ejagham', respectively, formed shoots after 6 weeks of culture. As much as 74% (14 out of 19) of the shoots regenerated in genotype NHC1-130 and 72% (18 out of 25) of those produced in genotype 'Ejagham' were transgenic. A DNA fragment corresponding to the wasabi defensin gene or the selection marker nptII was amplified by PCR from the genomic DNA of all regenerated plant clones rooted on hormone-free MS medium under the same selection pressure, suggesting their transgenic nature. Southern blot analysis confirmed successful integration of 1-5 copies of the transgene. RT-PCR, northern and western blot analyses revealed that wasabi defensin gene was expressed in transgenic lines. Transgenic lines showed increased levels of resistance to Alternaria solani, which causes Alternaria leaf spot and Fusarium oxysporum, which causes Fusarium wilt, as compared to that of untransformed plants. PMID:20552202

  18. Genetic Differentiation and Host Specificity Among Populations of Alternaria spp. Causing Brown Spot of Grapefruit and Tangerine x Grapefruit Hybrids in Florida.

    PubMed

    Peever, T L; Olsen, L; Ibañez, A; Timmer, L W

    2000-04-01

    ABSTRACT Alternaria spp. were sampled from brown spot lesions in several geographically separated citrus groves and different grapefruit and tangerine x grapefruit hybrid cultivars in Florida and screened for variation at 16 putative random amplified polymorphic DNA loci. Populations of the pathogen on two hybrids, Minneola and Orlando, in five locations throughout Florida were moderately differentiated (Nei's coefficient of gene differentiation [G(ST)] = 0.12) among locations. The hypothesis that host-specialized forms of Alternaria spp. cause brown spot on different Citrus spp. and cultivars was tested by estimating genetic differentiation among isolates sampled from different hosts and by pathogenicity assays. Isolates sampled from grapefruit and the hybrid cv. Nova were genetically distinct from isolates sampled from other hybrid cultivars including Robinson, Sunburst, Minneola, Orlando, and Murcott. No differentiation could be detected among isolates sampled from this latter group of hybrids. Quantitative pathogenicity assays on leaves using spray inoculation revealed that 'Nova' isolates were not significantly more pathogenic on 'Nova' compared with isolates from 'Minneola' and 'Orlando'. Similarly, grapefruit isolates were not significantly more pathogenic on grapefruit compared with isolates from 'Minneola'. Isolates from all hosts had similar disease rankings on each inoculated cultivar, with 'Minneola' the most susceptible, followed in decreasing order of susceptibility by 'Orlando', 'Sunburst', 'Nova', and 'Duncan' grapefruit. Rough lemon was generally immune to all isolates tested; however, occasional brown spot lesions were observed on leaves of this host with isolates from grapefruit. No evidence was found to support the hypothesis that unique genotypes of the pathogen, which are more virulent on 'Sunburst' or grapefruit, have been introduced to Florida. Populations of Alternaria spp. causing brown spot of citrus on grapefruit and 'Nova' in Florida are genetically distinct from isolates on other cultivars, and we speculate that these populations are in the early stages of adaptation to and possible speciation on these hosts. PMID:18944592

  19. Roles for SKN7 response regulator in stress resistance, conidiation and virulence in the citrus pathogen Alternaria alternata.

    PubMed

    Chen, Li-Hung; Lin, Ching-Hsuan; Chung, Kuang-Ren

    2012-10-01

    "Two-component" histidine kinase (HSK1) is the primary regulator of resistance to sugar osmotic stress and sensitivity to dicarboximide or phenylpyrrole fungicides in the citrus fungal pathogen Alternaria alternata. On the other hand, the mitogen-activated protein kinase HOG1 confers resistance solely to salts and oxidative stress. We report here independent and shared functions of the SKN7-mediated signaling pathway with HSK1 and HOG1. SKN7, a putative transcription downstream regulator of HSK1, is primarily required for cellular resistance to oxidative and sugar-induced osmotic stress. SKN7, perhaps acting in parallel with HOG1, is required for resistance to H(2)O(2), tert-butyl hydroperoxide, and cumyl peroxide, but not to the superoxide-generating compounds - menadione, potassium superoxide, and diamide. Because of phenotypic commonalities, SKN7 is likely involved in resistance to sugar-induced osmotic stress via the HSK1 signaling pathway. However, mutants lacking SKN7 displayed wild-type sensitivity to NaCl and KCl salts. SKN7 is constitutively localized in the nucleus regardless of H(2)O(2) treatment. When compared to the wild type, skn7 mutants exhibited lower catalase, peroxidase, and superoxide dismutase activities and induced significantly fewer necrotic lesions on the susceptible citrus cultivar. The skn7 mutant exhibited fungicide resistance at levels between the hsk1 and the hog1 mutant strains. Skn7/hog1 double mutants exhibited fungicide resistance, similar to the strain with a single AaHSK1 gene mutation. Moreover, the A. alternata SKN7 plays a role in conidia formation. Conidia produced by the skn7 mutant are smaller and have fewer transverse septae than those produced by wild type. All altered phenotypes in the mutant were restored by introducing and expressing a wild-type copy of SKN7 under control of the endogenous promoter. PMID:22902811

  20. Characterisation of Alternaria alternata manganese-dependent superoxide dismutase, a cross-reactive allergen homologue to Asp f 6.

    PubMed

    Gabriel, Marta F; Postigo, Idoia; Gutiérrez-Rodríguez, Antonio; Suñén, Ester; Guisantes, Jorge; Tomaz, Cândida T; Martínez, Jorge

    2015-07-01

    It is well known that Alternaria alternata presents a significant level of allergenic cross-reactivity with several other phylogenetically related and non-related allergenic moulds. To improve the molecular diagnosis, the identification and characterisation of all clinically relevant allergens, including both species-specific and cross-reacting proteins, is required. In this study we report the molecular and immunological characterisation of the A. alternata manganese-dependent superoxide dismutase (Alt a MnSOD) and its cross-reactivity with Asp f 6, a diagnostic marker allergen in allergic bronchopulmonary aspergillosis (ABPA). The cDNA coding for Alt a MnSOD sequence was isolated by RACE and PCR. Alt a MnSOD is a protein of 191 amino acids that presented significant homology and potential cross-reactive epitopes with Asp f 6. The recombinant protein was produced in Escherichia coli and the immunoreactivity was evaluated in patient sera. Immunoblotting analyses showed that seven of sixty-one A. alternata-sensitised patient sera and two ABPA patient sera reacted with the recombinant Alt a MnSOD. The native counterpart contained in both A. alternata and Aspergillus fumigatus extracts inhibited IgE binding to the recombinant molecule. The allergen was named Alt a 14 by the official Allergen nomenclature subcommittee. Thus, Alt a 14 is a relevant allergen in A. alternata sensitisation that may be used to improve diagnostic procedures. Evidence of cross-reactivity between Asp f 6 and Alt a 14-recognition by ABPA patient sera suggest the existence of an Alt a 14-mediated mechanism that, similar to Asp f 6, may be related to the pathogenesis of ABPA. PMID:25657116

  1. [Peculiarities of linear growth of the melanin-containing fungi Cladosporium sphaerospermum Penz. and Alternaria alternata (Fr.) Keissler].

    PubMed

    Vember, V V; Zhdanova, N N

    2001-01-01

    Results on determination of radial (linear) growth rate of melanin-containing fungi Cladosporium sphaerospermum Penz. and Alternaria alternata (Fr.) Keissler concerning place of their isolation and ecologic peculiarities are presented in the paper. Essential differences, as to all studied indices of the strains of C. sphaerospermum strains, isolated from premices of the ChNPP 4th unit from the control strains of this species have been established. Only strain 34 of C. sphaerospermum, isolated from the cable driving region of the "Shelter" object, which did not differ from the control strains as to all the studied indices, made the exception. The radial growth rate was 2-4 times as low and variability amplitude 10-30 times as high in strains 60 and 5-1 of C. sphaerospermum, (which suffered high radiation load), as in the control strains of this species. The radial growth rate of C. sphaerospermum studied strains was an order lower as a whole than that of A. alternata strains. All the above said evidence for implementation of K-type vital strategy by C. sphaerospermum species and in this connection one can suppose its active growth on the surface of walls and ferroconcrete structures of the ChNPP 4th unit. Absence of differences, as to the studied radial growth indices, between A. alternata strains isolated from the ChNPP 4th unit premices and control strains of the species can evidence for the existence of A. alternata species under the conditions of high radioactivity in the surviving state. PMID:11785260

  2. RNA-Seq derived identification of differential transcription in the chrysanthemum leaf following inoculation with Alternaria tenuissima

    PubMed Central

    2014-01-01

    Background A major production constraint on the important ornamental species chrysanthemum is black spot which is caused by the necrotrophic fungus Alternaria tenuissima. The molecular basis of host resistance to A. tenuissima has not been studied as yet in any detail. Here, high throughput sequencing was taken to characterize the transcriptomic response of the chrysanthemum leaf to A. tenuissima inoculation. Results The transcriptomic data was acquired using RNA-Seq technology, based on the Illumina HiSeq™ 2000 platform. Four different libraries derived from two sets of leaves harvested from either inoculated or mock-inoculated plants were characterized. Over seven million clean reads were generated from each library, each corresponding to a coverage of >350,000 nt. About 70% of the reads could be mapped to a set of chrysanthemum unigenes. Read frequency was used as a measure of transcript abundance and therefore as an identifier of differential transcription in the four libraries. The differentially transcribed genes identified were involved in photosynthesis, pathogen recognition, reactive oxygen species generation, cell wall modification and phytohormone signalling; in addition, a number of varied transcription factors were identified. A selection of 23 of the genes was transcription-profiled using quantitative RT-PCR to validate the RNA-Seq output. Conclusions A substantial body of chrysanthemum transcriptomic sequence was generated, which led to a number of insights into the molecular basis of the host response to A. tenuissima infection. Although most of the differentially transcribed genes were up-regulated by the presence of the pathogen, those involved in photosynthesis were down-regulated. PMID:24387266

  3. Composition of tobaccos from countries with high and low incidences of lung cancer. I. Selenium, polonium-210, Alternaria, tar, and nicotine

    SciTech Connect

    Bogden, J.D. (New Jersey Medical School, Newark); Kemp, F.W.; Buse, M.; Thind, I.S.; Louria, D.B.; Forgacs, J.; Llanos, G.; Terrones, I.M.

    1981-01-01

    Tobaccos from countries with high and low incidences of lung cancer were analyzed. Tobacco concentrations of polonium-210 were similar in cigarettes from high- and low-incidence countries, as were levels of cigarette smoke tar and nicotine. Tobaccos from low-incidence countries had significantly lower Alternaria spore counts. Mean selenium concentrations of tobaccos from the high-incidence countries (0.16 +- 0.05 ..mu..g/g) were significantly lower than those of tobaccos from the low-incidence countries (0.49 +- 0.22 ..mu..g/g).

  4. Cell Stem Cell Dear Student: Stem Cell Scientists' Advice

    E-print Network

    Cell Stem Cell Forum Dear Student: Stem Cell Scientists' Advice to the Next Generation Emily L on Stem Cells in Society, Stanford, CA 94305, USA 2Department of Family Practice, University of British@stanford.edu (C.T.S.) http://dx.doi.org/10.1016/j.stem.2013.05.007 For the field of pluripotent stem cell biology

  5. Original article Compatible stem taper and stem volume functions

    E-print Network

    Boyer, Edmond

    as merchantable vol- ume at any stem diameter along the trunk. Such functions may be used on their ownOriginal article Compatible stem taper and stem volume functions for oak (Quercus robur L and Q - In this paper we develop compatible stem taper and stem volume functions for oak (Quercus robur L and Q petraea

  6. ACTTS3 encoding a polyketide synthase is essential for the biosynthesis of ACT-toxin and pathogenicity in the tangerine pathotype of Alternaria alternata.

    PubMed

    Miyamoto, Y; Masunaka, A; Tsuge, T; Yamamoto, M; Ohtani, K; Fukumoto, T; Gomi, K; Peever, T L; Tada, Y; Ichimura, K; Akimitsu, K

    2010-04-01

    The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease of tangerine and tangerine hybrids. Sequence analysis of a genomic BAC clone identified part of the ACT-toxin TOX (ACTT) gene cluster, and knockout experiments have implicated several open reading frames (ORF) contained within the cluster in the biosynthesis of ACT-toxin. One of the ORF, designated ACTTS3, encoding a putative polyketide synthase, was isolated by rapid amplification of cDNA ends and genomic/reverse transcription-polymerase chain reactions using the specific primers designed from the BAC sequences. The 7,374-bp ORF encodes a polyketide synthase with putative beta-ketoacyl synthase, acyltransferase, methyltransferase, beta-ketoacyl reductase, and phosphopantetheine attachment site domains. Genomic Southern blots demonstrated that ACTTS3 is present on the smallest chromosome in the tangerine pathotype of A. alternata, and the presence of ACTTS3 is highly correlated with ACT-toxin production and pathogenicity. Targeted gene disruption of two copies of ACTTS3 led to a complete loss of ACT-toxin production and pathogenicity. These results indicate that ACTTS3 is an essential gene for ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and is required for pathogenicity of this fungus. PMID:20192828

  7. Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of Alternaria alternata.

    PubMed

    Ajiro, Naoya; Miyamoto, Yoko; Masunaka, Akira; Tsuge, Takashi; Yamamoto, Mikihiro; Ohtani, Kouhei; Fukumoto, Takeshi; Gomi, Kenji; Peever, Tobin L; Izumi, Yuriko; Tada, Yasuomi; Akimitsu, Kazuya

    2010-02-01

    ABSTRACT The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease of tangerines and tangerine hybrids. Sequence analysis of a genomic BAC clone identified a previously uncharacterized portion of the ACT-toxin biosynthesis gene cluster (ACTT). A 1,034-bp gene encoding a putative enoyl-reductase was identified by using rapid amplification of cDNA ends and polymerase chain reaction and designated ACTTS2. Genomic Southern blots demonstrated that ACTTS2 is present only in ACT-toxin producers and is carried on a 1.9 Mb conditionally dispensable chromosome by the tangerine pathotype. Targeted gene disruption of ACTTS2 led to a reduction in ACT-toxin production and pathogenicity, and transcriptional knockdown of ACTTS2 using RNA silencing resulted in complete loss of ACT-toxin production and pathogenicity. These results indicate that ACTTS2 is an essential gene for ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and is required for pathogenicity of this fungus. PMID:20055645

  8. Proteomic analysis of resistance mediated by Rcm 2.0 and Rcm 5.1, two loci controlling resistance to bacterial canker of tomato.

    PubMed

    Coaker, Gitta L; Willard, Belinda; Kinter, Michael; Stockinger, Eric J; Francis, David M

    2004-09-01

    Two quantitative trait loci from Lycopersicon hirsutum, Rcm 2.0 and Rcm 5.1, control resistance to Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato. Lines containing Rcm 2.0 and Rcm 5.1 and a susceptible control line were compared at 72 and 144 h postinoculation, using 2-dimensional gel electrophoresis to identify proteins regulated in response to C. michiganensis subsp. michiganensis infection. A total of 47 proteins were subjected to tandem mass spectrometry. Database queries with resulting spectra identified tomato genes for 26 proteins. The remaining 21 proteins were either identified in other species or possessed no homology to known proteins. Spectra were interpreted to deduce peptide amino acid sequences that were then used to query publicly available data. This approach identified tomato genes or expressed sequence tags for 44 of the proteins analyzed. Three superoxide dismutase (SOD) enzymes were differentially regulated among genotypes, and patterns of hydrogen peroxide accumulation were genotype- and tissue-specific, indicating a role for oxidative stress in response to C. michiganensis subsp. michiganensis. Steady-state mRNA and protein levels for SOD, thioredoxin M-type, S-adenosylhomocysteine hydrolase, and pathogenesis-related proteins demonstrated similar patterns of differential regulation. Lines containing Rcm 2.0 and Rcm 5.1 accumulate different proteins and steady-state mRNAs in response to inoculation, suggesting that the two loci may confer resistance through distinct mechanisms. PMID:15384492

  9. The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease

    PubMed Central

    Ahmad, Abdelmonim Ali; Askora, Ahmed; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac) strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 600 nm long. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs), some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII), ORF2 (pV), ORF6 (pIII), and ORF8 (pVI). XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB) and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease. PMID:25071734

  10. Tracking adult stem cells

    Microsoft Academic Search

    Hugo J Snippert; Hans Clevers

    2011-01-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue—known as their niche—and thus, stem-cell studies should preferably be performed in a physiological context, rather than outside their natural environment. The mouse is an attractive model in which to study adult mammalian

  11. Stem Cell Biology

    Microsoft Academic Search

    Elizabeth O. Hexner; Stephen G. Emerson

    \\u000a Stem cells are functionally defined as long-lived cells that can both self-renew and differentiate into multiple cell types.\\u000a Embryonic stem cells, considered totipotent cells, give rise to all embryonic tissue layers and, consequently, all tissue\\u000a types. Hematologists\\/oncologists are perhaps most familiar with hematopoietic stem cells (HSCs): the single pluripotent cell\\u000a that can give rise to all lymphoid, myeloid and erythroid

  12. Valve stem oil deflector

    SciTech Connect

    Stritzke, B.G.

    1988-08-16

    This patent describes an oil deflector for attachment to a valve stem of an internal combustion engine or the like comprising a molded plastic cup having a generally cylindrical wall section and an enlarged transversely extending end wall defining a neck portion, having an opening for receiving a valve stem, a radially inwardly opening annular groove on an inner face of the opening in the neck portion, an O-ring in the groove, circumferentially spaced teeth on opposite sides of the groove each of which is engageable with a valve stem extending through the neck portion of the deflector to preclude tipping of the deflector relative to the valve stem.

  13. Hypertensive brain stem encephalopathy.

    PubMed

    Liao, Pen-Yuan; Lee, Chien-Chang; Chen, Cheng-Yu

    2015-01-01

    A 48-year-old man presented with headache and extreme hypertension. Computed tomography showed diffuse brain stem hypodensity. Magnetic resonance imaging revealed diffuse brain stem vasogenic edema. Hypertensive brain stem encephalopathy is an uncommon manifestation of hypertensive encephalopathy, which classically occurs at parietooccipital white matter. Because of its atypical location, the diagnosis can be challenging. Moreover, the coexistence of hypertension and brain stem edema could also direct clinicians toward a diagnosis of ischemic infarction, leading to a completely contradictory treatment goal. PMID:25082596

  14. Membrane Glycolipids in Stem Cells

    PubMed Central

    Yu, Robert K.; Suzuki, Yusuke; Yanagisawa, Makoto

    2015-01-01

    Stem cells, such as embryonic stem cells, hematopoietic stem cells, neural stem cells, mesenchymal stem cells, and very small embryonic-like stem cells, are undifferentiated cells that are endowed with a high potential for proliferation and the capacity for self-renewal with retention of pluri/multipotency to differentiate into their progenies. Recently, studies regarding the biological functions of glycolipids and cell surface microdomains (caveolae, lipid rafts, or glycolipid-enriched microdomains) in stem cells are emerging. In this review, we introduce the expression patterns of glycolipids and the functional roles of cell surface microdomains in stem cells. PMID:19716368

  15. Designing for STEM Integration

    ERIC Educational Resources Information Center

    Berland, Leema K.

    2013-01-01

    We are increasingly seeing an emphasis on STEM integration in high school classrooms such that students will learn and apply relevant math and science content while simultaneously developing engineering habits of mind. However, research in both science education and engineering education suggests that this goal of truly integrating STEM is rife…

  16. Lock For Valve Stem

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Guirguis, Kamal S.

    1991-01-01

    Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

  17. Adult stem cell plasticity

    Microsoft Academic Search

    Richard Poulsom; Malcolm R. Alison; Stuart J. Forbes; Nicholas A. Wright

    2002-01-01

    Observations made in the last few years support the existence of pathways, in adult humans and rodents, that allow adult stem cells to be surprisingly flexible in their differentiation repertoires. Termed plasticity, this property allows adult stem cells, assumed, until now, to be committed to generating a fixed range of progeny, to switch, when they have been relocated, to make

  18. Bioreactors Stem Cells

    E-print Network

    Schüler, Axel

    Keywords Bioreactors Stem Cells Regenerative Medicine Tissue Engineering Pharmacology » Prof. M.; yeZhelyev, M.; eMMrich, F.; o'regan, r.; bader, a. Quantum dots for human mesenchymal stem cells and mechanical forces mediated to the cells by the matrix. The in vivo extracellular matrix constitutes

  19. I-STEM

    NSDL National Science Digital Library

    The University of Illinois at Urbana-Champaign has developed a multi-pronged approach to remedying the lack of academic emphasis on the STEM subjects, from preschool through college, as well as the lack of interest in STEM subjects on the part of youth in the United States. Visitors can read about the University's four goals under the "Goals" tab at the top of any page. The "STEM Ed Projects" tab contains a directory of externally funded projects divided into four categories, and which are then further divided into subcategories. Visitors will find such projects as "Improving Supply and Demand Data for the Preparation of Secondary Science and Math Teachers" and "Clean Energy Education Workshop", under the category that aims to shape policy and advocate for STEM education. The "Resources" tab contains half a dozen categories under which visitors will find Outreach Resources, Teacher Development and Resources, and Policy and Advocacy for STEM Ed.

  20. ADULT MESENCHYMAL STEM CELLS DERIVED FROM EMBRYONIC STEM CELLS

    Microsoft Academic Search

    N. L. BOYD; P. BOSCH; S. L. STICE

    Mesenchymal stem cells (MSC) are useful in cell therapy and stem cell research but they have a limited lifespan in culture. Our goal was to develop a unique and limitless supply of mesenchymal stem cells derived from human embryonic stem cells, opening up new uses and enhance existing uses of these important cell types. For any application that uses large

  1. Cell Stem Cell Stem Cell Epigenetics: Looking Forward

    E-print Network

    Sander, Maike

    Cell Stem Cell Voices Stem Cell Epigenetics: Looking Forward Epigenetics in Adult SCs The integrity of tissues is maintained by adult stem cells during adulthood. How- ever, recent work indicates that tissues often contain more than one population of stem cells that are located at distinct niches and display

  2. ``Stemness'': Transcriptional Profiling of Embryonic and Adult Stem Cells

    Microsoft Academic Search

    Miguel Ramalho-Santos; Soonsang Yoon; Yumi Matsuzaki; Richard C. Mulligan; Douglas A. Melton

    2002-01-01

    The transcriptional profiles of mouse embryonic, neural, and hematopoietic stem cells were compared to define a genetic program for stem cells. A total of 216 genes are enriched in all three types of stem cells, and several of these genes are clustered in the genome. When compared to differentiated cell types, stem cells express a significantly higher number of genes

  3. Cell Stem Cell Control of Stem Cell Fate by Physical

    E-print Network

    Chen, Christopher S.

    Cell Stem Cell Review Control of Stem Cell Fate by Physical Interactions with the Extracellular, Philadelphia, PA 19104, USA 5Stem Cell Laboratory, Pennington Biomedical Research Center, Louisiana State.06.016 A diverse array of environmental factors contributes to the overall control of stem cell activity

  4. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase-inhibiting fungicides in Alternaria solani.

    PubMed

    Mallik, I; Arabiat, S; Pasche, J S; Bolton, M D; Patel, J S; Gudmestad, N C

    2014-01-01

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight; therefore, the application of fungicides is the primary means of achieving disease control. Previous work in our laboratory reported resistance to the succinate dehydrogenase-inhibiting (SDHI) fungicide boscalid in this plant pathogen with a concomitant loss of disease control. Two phenotypes were detected, one in which A. solani isolates were moderately resistant to boscalid, the other in which isolates were highly resistant to the fungicide. Resistance in other fungal plant pathogens to SDHI fungicides is known to occur due to amino acid exchanges in the soluble subunit succinate dehydrogenase B (SdhB), C (SdhC), and D (SdhD) proteins. In this study, the AsSdhB, AsSdhC, and AsSdhD genes were analyzed and compared in sensitive (50% effective concentration [EC50] < 5 ?g ml(-1)), moderately resistant (EC50 = 5.1 to 20 ?g ml(-1)), highly resistant (EC50 = 20.1 to 100 ?g ml(-1)), and very highly resistant (EC50 > 100 ?g ml(-1)) A. solani isolates. In total, five mutations were detected, two in each of the AsSdhB and AsSdhD genes and one in the AsSdhC gene. The sequencing of AsSdhB elucidated point mutations cytosine (C) to thymine (T) at nucleotide 990 and adenine (A) to guanine (G) at nucleotide 991, leading to an exchange from histidine to tyrosine (H278Y) or arginine (H278R), respectively, at codon 278. The H278R exchange was detected in 4 of 10 A. solani isolates moderately resistant to boscalid, exhibiting EC50 values of 6 to 8 ?g ml(-1). Further genetic analysis also confirmed this mutation in isolates with high and very high EC50 values for boscalid of 28 to 500 ?g ml(-1). Subsequent sequencing of AsSdhC and AsSdhD genes confirmed the presence of additional mutations from A to G at nucleotide position 490 in AsSdhC and at nucleotide position 398 in the AsSdhD, conferring H134R and H133R exchanges in AsSdhC and AsSdhD, respectively. The H134R exchange in AsSdhC was observed in A. solani isolates with sensitive, moderate, highly resistant, and very highly resistant boscalid phenotypes, and the AsSdhD H133R exchange was observed in isolates with both moderate and very high EC50 value boscalid phenotypes. Detection and differentiation of point mutations in AsSdhB resulting in H278R and H278Y exchanges in the AsSdhB subunit were facilitated by the development of a mismatch amplification mutation assay. Detection of these two mutations in boscalid-resistant isolates, in addition to mutations in AsSdhC and AsSdhD resulting in an H134R and H133R exchange, respectively, was achieved by the development of a multiplex polymerase chain reaction to detect and differentiate the sensitive and resistant isolates based on the single-nucleotide polymorphisms present in all three genes. A single A. solani isolate with resistance to boscalid did not contain any of the above-mentioned exchanges but did contain a substitution of aspartate to glutamic acid at amino acid position 123 (D123E) in the AsSdhD subunit. Among A. solani isolates possessing resistance to boscalid, point mutations in AsSdhB were more frequently detected than mutations in genes coding for any other subunit. PMID:23901829

  5. Lampropedia puyangensis sp. nov., isolated from symptomatic bark of Populus × euramericana canker and emended description of Lampropedia hyalina (Ehrenberg 1832) Lee et al. 2004.

    PubMed

    Li, Yong; Wang, Tao; Piao, Chun-Gen; Wang, Lai-Fa; Tian, Guo-Zhong; Zhu, Tian-Hui; Guo, Min-Wei

    2015-08-01

    A Gram-stain negative, Neisser-stain negative, aerobic, non-motile, non-spore-forming, slimy, glossy bacterial strain with single or clustered coccoid cells and white colony colour, designated as 2-bin(T), was isolated from cankered bark tissue of Populus × euramericana. The strain was found to grow at 15-40 °C and pH 5-10, with an optimum of 30 °C and pH 8.0. The strain was found to be negative with respect to catalase and positive for oxidase activity, nitrate reduction and Voges-Proskauer reaction. Analysis of 16S rRNA gene sequence data indicated that the isolate belongs to the genus Lampropedia, having sequence similarity of 96.24 % with Lampropedia hyalina ATCC11041(T). DNA-DNA relatedness of strain 2-bin(T) with L. hyalina JCM 21380(T) was 26.7 ± 4.6 %. The DNA G+C content of strain 2-bin(T) was determined to be 57 % and the major cellular fatty acids were identified as C16:0, C16:1 ?7c/C16:1 ?6c and C18:1 ?7c. The polar lipid profile of strain 2-bin(T) was found to contain diphosphatidylglycerol, a glycolipid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, a phospholipid, phosphatidylmonomethylethanolamine and three unidentified lipids (L1, L2, L3). Based on molecular data and physiological and biochemical characteristics, strain 2-bin(T) is considered to represent a novel species in the genus Lampropedia, for which the name Lampropedia puyangensis sp. nov. is proposed. The type strain is 2-bin(T) (= CFCC 10925(T) = KCTC 32235(T)). PMID:25991383

  6. Prostate cancer stem cells

    PubMed Central

    Lang, SH; Frame, FM; Collins, AT

    2009-01-01

    Despite the discovery over 60 years ago by Huggins and Hodges 1 that prostate cancers respond to androgen deprivation therapy, hormone-refractory prostate cancer remains a major clinical challenge. There is now mounting evidence that solid tumours originate from undifferentiated stem cell-like cells coexisting within a heterogeneous tumour mass that drive tumour formation, maintain tumour homeostasis and initiate metastases. This review focuses upon current evidence for prostate cancer stem cells, addressing the identification and properties of both normal and transformed prostate stem cells. PMID:19040209

  7. Stem Cell Differentiation Game

    NSDL National Science Digital Library

    2013-07-30

    This game uses a modified Uno deck to review concepts related to stem cell research and diabetes. Specifically, it covers material in the "Pulse-Chase Primer," "Pancreatic Beta Cells," and "Microarrays and Stem Cells" activities from the same resource which may or may not be necessary to complete prior to this activity (depending on learner's prior knowledge). Learners accumulate points and answer questions about stem cells, development, and microarrays so that they can be the first to differentiate into a pancreatic beta (?) cell. This activity is recommended for learners studying Biology at the High School (honors, IB and AP) or Undergraduate level.

  8. Mesenchymal autologous stem cells.

    PubMed

    Falavigna, Asdrubal; da Costa, Jaderson Costa

    2015-02-01

    The use of cell-based therapies for spinal cord injuries has recently gained prominence as a potential therapy or component of a combination strategy. Experimental and clinical studies have been performed using mesenchymal stem cell therapy to treat spinal cord injuries with encouraging results. However, there have been reports on the adverse effects of these stem cell-based therapies, especially in the context of tumor modulation. This article surveys the literature relevant to the potential of mesenchymal autologous stem cells for spinal cord injuries and their clinical implications. PMID:23402865

  9. Stem cell niches in mammals

    Microsoft Academic Search

    Thimios A. Mitsiadis; Ornella Barrandon; Ariane Rochat; Yann Barrandon; Cosimo De Bari

    2007-01-01

    Stem cells safeguard tissue homeostasis and guarantee tissue repair throughout life. The decision between self-renewal and differentiation is influenced by a specialized microenvironment called stem cell niche. Physical and molecular interactions with niche cells and orientation of the cleavage plane during stem cell mitosis control the balance between symmetric and asymmetric division of stem cells. Here we highlight recent progress

  10. Cell Stem Cell Clinical Progress

    E-print Network

    Zandstra, Peter W.

    Cell Stem Cell Clinical Progress Rapid Expansion of Human Hematopoietic Stem Cells by Automated *Correspondence: peter.zandstra@utoronto.ca DOI 10.1016/j.stem.2012.01.003 SUMMARY Clinical hematopoietic implementations of hematopoietic stem cells (HSCs) and their deriva- tives further increase interest in strategies

  11. LESSON PLAN Stem Cell Discussion

    E-print Network

    Rambaut, Andrew

    LESSON PLAN Stem Cell Discussion Learning objectives Students will: · consider the implications of stem cell research · research the current research situation · debate the future of stem cell of the Wellcome Trust, discusses why stem cells have the potential to treat many debilitating diseases, and why

  12. Disguising adult neural stem cells

    Microsoft Academic Search

    Cindi M Morshead; Derek van der Kooy

    2004-01-01

    A description of adult neural stem cells has remained somewhat elusive. With no unique and definitive markers to label stem cells in general, neural stem cells are difficult to identify definitively and one is forced to examine cell behavior — leading to the retrospective identification of a stem cell. The most prevalent view in the literature describes the adult forebrain

  13. Clonal interrogation of stem cells

    Microsoft Academic Search

    Kristin Hope; Mickie Bhatia

    2011-01-01

    Individual stem cells are functionally defined by their self-renewal and differentiation potential. Methods for clonal analysis are essential for understanding stem cells, particularly given the increasing evidence for stem-cell heterogeneity. Stem cells reside within complex microenvironments, making single-cell analysis particularly challenging. Furthermore, simultaneous molecular and functional characterization of single stem cells is not trivial. Here we explore clonal assays applied

  14. STEM Careers Middle School

    NSDL National Science Digital Library

    2009-11-09

    This brief video from WPSU introduces a diverse group of middle school students with interests in STEM careers. Whether creating robots or designing solar cars, each student dreams of activities beyond the stereotypical view of a nerdy scientist.

  15. Stem Cell Niche

    Microsoft Academic Search

    Pei Wen; Pei Sun; Rongwen Xi

    \\u000a The adult stem cells are essential for maintaining tissue homeostasis and commonly reside in specific local microenvironment\\u000a named niche. The niche keeps stem cells in multipotent state, prevents them from precocious differentiation and positions\\u000a them to undergo asymmetric division to produce differentiated ­progenies for tissue regeneration. The niches employ a variety\\u000a of factors including cell adhesion molecules, extra cellular matrix,

  16. Hematopoietic Stem Cells

    Microsoft Academic Search

    Malcolm A. S. Moore

    \\u000a Hematopoietic stem cells (HSCs) are the most well-characterized tissue-specific stem cell. Over 50 years of basic research\\u000a and clinical application has provided insight into the molecular and cellular mechanisms of HSC biology. HSC undergo self-renewal\\u000a by symmetric or asymmetric division, or differentiation to common myeloid progenitors and progressively more differentiated\\u000a myeloid and lymphoid progeny. The chemokine SDF-1\\/ CXCL12 produced by

  17. [Cancer stem cells].

    PubMed

    Wieczorek, Katarzyna; Niewiarowska, Jolanta

    2012-01-01

    Cancer stem cell theory gains increasingly greater significance in the world of medicine. Numerous findings of scientific research in vivo and in vitro indicate that it is the population of undifferentiated, self-renewing cells which is responsible for recurrence of cancer and metastasis. Similarly to normal stem cells, cancer stem cells (CSC) function in the environment of the other cells of the organism, called the niche, where they receive signals for differentiation and proliferation processes. Disorders in the signaling pathways between CSC and the niche that result from e.g. acquired oncogenic mutations may lead to uncontrolled proliferation of stem cells, gaining independence from the primary niche or settling a new microenvironment. CSC are identified on the basis of specific markers - membrane proteins or cell enzymes. Methods based on the measurement of dye fluorescence (obtaining side population, SP) or fluorescence of the fluorophore conjugated with a monoclonal antibody directed against the specific CSC marker are used for isolation. A different method obtains morphologically miscellaneous clones by single cell cloning: holo-, mero- and paraclones. Tumor forming assay in NOD/SCID mice is a standard in vivo test that confirms the stem character of isolated cells. However, this model may not fully reflect the complexity of cancer illnesses in human beings. Solving the mystery of oncogenesis, including the existence of cancer stem cells, is undoubtedly one of the priorities of contemporary medicine that should contribute to the improvement of cancer therapy.  PMID:23001204

  18. General Information about Childhood Brain Stem Glioma

    MedlinePLUS

    ... Treatment Childhood Ependymoma Treatment Brain Cancer Research Childhood Brain Stem Glioma Treatment (PDQ®) General Information About Childhood Brain Stem Glioma Key Points Childhood brain stem glioma ...

  19. Stages of Childhood Brain Stem Glioma

    MedlinePLUS

    ... Treatment Childhood Ependymoma Treatment Brain Cancer Research Childhood Brain Stem Glioma Treatment (PDQ®) General Information About Childhood Brain Stem Glioma Key Points Childhood brain stem glioma ...

  20. Chemotherapy targeting cancer stem cells

    PubMed Central

    Liu, Haiguang; Lv, Lin; Yang, Kai

    2015-01-01

    Conventional chemotherapy is the main treatment for cancer and benefits patients in the form of decreased relapse and metastasis and longer overall survival. However, as the target therapy drugs and delivery systems are not wholly precise, it also results in quite a few side effects, and is less efficient in many cancers due to the spared cancer stem cells, which are considered the reason for chemotherapy resistance, relapse, and metastasis. Conventional chemotherapy limitations and the cancer stem cell hypothesis inspired our search for a novel chemotherapy targeting cancer stem cells. In this review, we summarize cancer stem cell enrichment methods, the search for new efficient drugs, and the delivery of drugs targeting cancer stem cells. We also discuss cancer stem cell hierarchy complexity and the corresponding combination therapy for both cancer stem and non-stem cells. Learning from cancer stem cells may reveal novel strategies for chemotherapy in the future. PMID:26045975

  1. Valve stem and packing assembly

    DOEpatents

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  2. Valve stem and packing assembly

    DOEpatents

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  3. The FUS3 MAPK signaling pathway of the citrus pathogen Alternaria alternata functions independently or cooperatively with the fungal redox-responsive AP1 regulator for diverse developmental, physiological and pathogenic processes

    Microsoft Academic Search

    Ching-Hsuan Lin; Siwy Ling Yang; Nan-Yi Wang; Kuang-Ren Chung

    2010-01-01

    Alternaria alternata, the fungus that causes citrus brown spot, invades its hosts primarily through the production and action of a host-selective ACT toxin that kills citrus cells prior to invasion. In this study, we show that, in the tangerine pathotype of A. alternata, a mitogen-activated protein kinase (MAPK)-mediated signaling pathway governs a number of biological functions, either separately or in

  4. STEM Guitar Project

    NSDL National Science Digital Library

    This ATE professional development project is a collaboration between STEM faculty teams from Butler County Community College (Butler, PA), Purdue University (West Lafayette, IN), Sinclair Community College (Dayton, OH), Ventura College (Ventura, CA), College of the Redwoods (Eureka, Ca.), as well as high school STEM faculty in each of the states involved. Faculty teams at the respective locations are working together to design, build, and analyze solid body electric guitars as a means of learning applied concepts of science, technology, engineering, mathematics, and as a means of understanding product lifecycle management. This experience is providing teachers and students an accurate simulation of the collaborative design and rapid manufacturing processes routinely used in business and industry. Over 150 STEM faculty members from high schools and community colleges are participating in an intense five-day Summer Professional Development Program and are having extensive academic year follow-up activities. The teacher participants are using these processes and simulations in their classrooms to enhance the STEM laboratory learning experience. Nearly 5000 students are learning about cross-disciplinary STEM problem solving that is becoming increasingly important for new design technicians to experience.On the site, visitors can find curriculum materials including classroom tools and information on guitar fabrication. There are also details of upcoming workshops and professional development opportunities. In the Storefront section, visitors can learn about how to purchase a guitar kit.

  5. Targeting K-RAS Induced Stem-ness (Video)

    Cancer.gov

    View this video on YouTube. Dr. Frank McCormick, UCSF, describes recent progress in understanding of connections between KRAS and stem-ness. This seminar was presented at the NCI in Frederick, Maryland, June 11, 2015.

  6. 5. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (28' WIDE HARDESTY CAST IRON SLIDE HEADGATE), LOOKING NORTHEAST - High Mountain Dams in Bonneville Unit, Duck Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  7. 4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF INCLINED OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY VERTICAL LIFT GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Pot Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  8. 7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (15' HARDESTY MODEL 115 GATE), LOOKING NORTHWEST - High Mountain Dams in Bonneville Unit, Marjorie Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  9. 5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE, LOOKING NORTHWEST - High Mountain Dams in Upalco Unit, Drift Lake Dam, Ashley National Forest, 11.4 miles Northwest of Swift Creek Campground, Mountain Home, Duchesne County, UT

  10. 6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE (18' HARDESTY GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Long Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  11. 5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF INCLINED OUTLET GATE WHEEL, STEM AND STEM GUIDE, (12' DIAMETER HARDESTY MODEL 112 CIRCULAR GATE), LOOKING NORTHEAST - High Mountain Dams in Bonneville Unit, Island Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  12. 5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE, STEM, STEM GUIDE AND WHEEL (10' HARDESTY CAST IRON VERTICAL LIFT GATE), LOOKING WEST - High Mountain Dams in Bonneville Unit, Weir Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  13. 5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE (HARDESTY CAST IRON RECTANGULAR SLIDE GATE), LOOKING SOUTHWEST - High Mountain Dams in Bonneville Unit, Lost Lake Dam, Kamas, Summit County, UT

  14. 7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF UPRIGHT OUTLET GATE, WHEEL STEM AND STEM GUIDE (14' DIAMETER CIRCULAR CALCO CAST IRON SLIDE GATE), LOOKING SOUTHEAST - High Mountain Dams in Bonneville Unit, Fire Lake Dam, Wasatch National Forest, Kamas, Summit County, UT

  15. Pathways to Science: STEM

    NSDL National Science Digital Library

    Sponsored by NASA and the National Science Foundation, the Pathways to Science Project was created by the Institute for Broadening Participation to support "pathways to the STEM fields: science, technology, engineering, and mathematics." The project works on connecting underrepresented groups with STEM programs, funding, mentoring, and resources. The "Students" area features a sign-in area where students can sign up to receive targeted emails that will inform them of new STEM-focused scholarship and mentoring opportunities. The "Programs" area features a database of over 1500 programs designed for K-8 students, college educators, and undergraduate students. Additionally, the site also includes a "News" area where users can learn about recent success stories from universities around the United States, along with the particulars of upcoming conferences and seminars.

  16. Microarrays and Stem Cells

    NSDL National Science Digital Library

    Mary Colvard

    2010-01-01

    In this activity, learners use microarray technology to determine which genes are turned on and off at various points in the differentiation of pluripotent stem cells on their way to becoming pancreatic ? cells. An introductory PowerPoint, reading, video clip and an animation provide learners with background information needed to interpret the results of a paper microarray simulation. Learners will position cDNA strips on mini-microarrays to discover which genes are expressing, to what degree they are expressing, and which are not. They use these findings to trace the differentiation of embryonic stem cells that give rise to pancreatic ? cells and other cell types. The role of growth factors and proximity of other cell types is central to learners understanding how researchers may direct the ultimate fate of stem cells. The value of this in treating diabetes is also discussed. This activity is recommended for learners studying Biology at the High School (honors, IB and AP) or Undergraduate level.

  17. Germline Stem Cells

    PubMed Central

    Spradling, Allan; Fuller, Margaret T.; Braun, Robert E.; Yoshida, Shosei

    2011-01-01

    Sperm and egg production requires a robust stem cell system that balances self-renewal with differentiation. Self-renewal at the expense of differentiation can cause tumorigenesis, whereas differentiation at the expense of self-renewal can cause germ cell depletion and infertility. In most organisms, and sometimes in both sexes, germline stem cells (GSCs) often reside in a defined anatomical niche. Factors within the niche regulate a balance between GSC self-renewal and differentiation. Asymmetric division of the germline stem cell to form daughter cells with alternative fates is common. The exception to both these tendencies is the mammalian testis where there does not appear to be an obvious anatomical niche and where GSC homeostasis is likely accomplished by a stochastic balance of self-renewal and differentiation and not by regulated asymmetric cell division. Despite these apparent differences, GSCs in all organisms share many common mechanisms, although not necessarily molecules, to guarantee survival of the germline. PMID:21791699

  18. Normal Stem Cells and Cancer Stem Cells: The Niche Matters

    Microsoft Academic Search

    Linheng Li; William B. Neaves

    Scientists have tried for decades to understand cancer development in the context of therapeutic strategies. The realization that cancers may rely on ''cancer stem cells'' that share the self-renewal feature of normal stem cells has changed the perspective with regard to new approaches for treating the disease. In this review, we propose that one of the differences between normal stem

  19. Cancer stem cells and “stemness” genes in neuro-oncology

    Microsoft Academic Search

    Silvia K. Nicolis

    2007-01-01

    The main properties of stem cells include long-term self-renewal and the capacity to give rise to one or more types of differentiated progeny. Recently, much evidence was provided that leukemia and tumor maintenance and growth are sustained by a small proportion of cells exhibiting stem cell properties. In neural tumors, stem cells have been detected in glioblastoma, medulloblastoma and ependymoma.

  20. Stem cells today: B1. Bone marrow stem cells

    Microsoft Academic Search

    RG Edwards

    2004-01-01

    This review is the second in a series of four devoted to the analysis of recent studies on stem cells. The first considered embryo stem cells (ES). This review covers bone marrow stem cells. They are analysed initially in a historical perspective, and then in relation to foundation studies in the later 20th century before a detailed analysis is presented

  1. Benefits Stemming from Space Exploration

    E-print Network

    Waliser, Duane E.

    Benefits Stemming from Space Exploration September 2013 International Space Exploration Coordination Group #12; This page is intentionally left blank #12;ISECG ­ Benefits Stemming from Space Exploration Table of Content Executive Summary

  2. GIS in STEM Education

    E-print Network

    Baker, Michael

    2014-11-19

    GIS in STEM Education? GIS Day 2014 – University of Kansas? November 19, 2014 Esri Education Manager Adjunct Researcher, Center for STEM Learning University of Kansas @trbaker? tbaker@esri.com? Thomas R. Baker? Images used... in this presentation:? gps.gov; esri.com; gis.com; garmin.com; popularmechaics.com ? GeoSpatial Tech? What is GIS? ? http://arcgis.com ? http://connectED.esri.com? Learning? A Tool for Thinkers? ? •? Think about a topic or a place ... •? Ask a question about...

  3. STEM2Stern

    NSDL National Science Digital Library

    The STEM2Stern Coordination Office works alongside all of the Naval Laboratories and Warfare Centers to offer a broad range of STEM education and outreach programs to support the next generation of scientists and engineers who will bring their talents to U.S. Naval laboratories and warfighting centers. On this site, visitors will find information about the multiple programs offered in each of the fifty states, success stories of students who have gone through these programs, and information for all those interested to get involved (students, educators, parents, and mentors).

  4. STEM on the radio

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  5. Stem Cells in Intraepithelial Neoplasia

    Microsoft Academic Search

    Nicholas A. Wright

    \\u000a Tumours are thought to contain a subpopulation of self-renewing stem cells, the so-called cancer stem cells, which maintain the tumour. Moreover, tumours themselves are thought to arise from organ-specific stem cells. In epithelia, transformation of these cells leads to spread of a mutated stem cell clone through the epithelial sheet, leading to the development of a pre-invasive lesion. Barrett’s oesophagus

  6. Stem Cell Interaction with Topography

    Microsoft Academic Search

    Benjamin K. K. Teo; Soneela Ankam; Evelyn K. F. Yim

    \\u000a The growth and differentiation of stem cells are regulated by biochemical and biophysical cues in the extracellular microenvironment.\\u000a Increasing evidences have shown that substrate topography, one of the biophysical properties of the microenvironment, can\\u000a affect stem cell fate, such as the maintenance of embryonic stem cells and the differentiation of adult and embryonic stem\\u000a cells. The underlying mechanism of how

  7. Microtechnology for Stem Cell Culture

    Microsoft Academic Search

    Elena Serena; Elisa Cimetta; Camilla Luni; Nicola Elvassore

    \\u000a Advances in stem cell research in recent decades have been aided by progress in the development of novel technologies aimed\\u000a at biological systems. At the same time mimicking stem cell niches in vitro has become crucial for both basic stem cell research\\u000a and the development of innovative therapies based on stem cells. Innovative microscale technologies can contribute to our\\u000a quantitative

  8. Laser biomodulation on stem cells

    NASA Astrophysics Data System (ADS)

    Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

    2001-08-01

    Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

  9. Stem Cells and Renal Regeneration

    Microsoft Academic Search

    C. Roufosse; H. T. Cook

    2008-01-01

    The role of embryonal or adult stem cells, in particular bone marrow (BM)-derived stem cells, in regenerating the kidney after injury has been the subject of intensive investigation. BM-derived stem cells have been shown to give rise to small numbers of most renal cell types, including tubular cells, mesangial cells, podocytes, vascular cells and interstitial cells. However, the role this

  10. Teaching STEM Means Teacher Learning

    ERIC Educational Resources Information Center

    O'Neill, Tara; Yamagata, Lisa; Yamagata, Justin; Togioka, Susan

    2012-01-01

    Three experienced science teachers at a middle school tell about their first-year journey of adopting STEM pedagogy. STEM did not materialize as planned, but in the end it worked out. Some observations and advice: Transitioning to STEM requires leaving comfort zones. Teachers may need the help of an experienced guide. Many students have been…

  11. STEM--Beyond the Acronym

    ERIC Educational Resources Information Center

    Vasquez, Jo Anne

    2015-01-01

    When most educators think of STEM education, they think of fully integrated projects seamlessly combining all four disciplines--science, technology, engineering, and mathematics. Although such transdisciplinary STEM units are ideal, writes Vasquez, they are not the only way to give students valuable STEM experiences. She gives examples of two…

  12. Cell Stem Cell Brief Report

    E-print Network

    Church, George M.

    Cell Stem Cell Brief Report Reprogramming of T Cells from Human Peripheral Blood Yuin-Han Loh,1,2,5,9,10,* 1Stem Cell Transplantation Program, Division of Pediatric Hematology Oncology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA 2Harvard Stem Cell Institute, Cambridge, MA 02138, USA 3

  13. National STEM Promoting Awareness of

    E-print Network

    US Army Corps of Engineers

    National STEM Awareness Program Promoting Awareness of Opportunities in Science, Technology, Engineering and Math (STEM) among Underrepresented Students Blanket Purchase Agreement (BPA) available for all.o.roberts@usace.army.mil HowdoISupportaSTEMAwarenessProgram? · Identify a school or desired STEM Awareness Program site (location

  14. Stem cells find their niche

    Microsoft Academic Search

    Allan Spradling; Daniela Drummond-Barbosa; Toshie Kai

    2001-01-01

    The concept that stem cells are controlled by particular microenvironments known as 'niches' has been widely invoked. But niches have remained largely a theoretical construct because of the difficulty of identifying and manipulating individual stem cells and their surroundings. Technical advances now make it possible to characterize small zones that maintain and control stem cell activity in several organs, including

  15. Controversies over stem cell research

    Microsoft Academic Search

    Gorka Orive; Rosa M. Hernández; Alicia R. Gascón; Manoli Igartua; José Luis Pedraz

    2003-01-01

    Much interest and effort has focused on the therapeutic potential of stem cell technology to treat presently intractable diseases. However, this scientific promise has been accompanied by important issues, including ethical hurdles, political policies and dilemmas concerning cell-source selection (embryonic versus adult stem cells). Although the contribution of stem cells to medical research seems enormous, many countries now face complex

  16. STEM At Work

    NSDL National Science Digital Library

    STEM (Science Technology Engineering & Math) at work, presented by the Florida Advanced Technological Education Center, includes a number of educational puzzles for use in the classroom. Puzzles include an energy audit exercise, measurement of air bag movement, and diesel fuel additive volatility.

  17. Cell Stem Cell Perspective

    E-print Network

    Zhang, Yi

    for genetic alterations that facilitate cell prop- agation (Figure 1C). In addition to these causes, certainCell Stem Cell Perspective Genetic and Epigenetic Variations in iPSCs: Potential Causes Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA 4Department of Genetics, Harvard

  18. Advancing Diversity in STEM

    ERIC Educational Resources Information Center

    Hill, Paul L.; Shaw, Rose A.; Taylor, Jan R.; Hallar, Brittan L.

    2011-01-01

    Although progress has been made, greater efforts are needed to promote faculty diversity at the college and university levels, especially in STEM fields. Thus, it is important to elucidate best practices both for increasing awareness of diversity issues pertaining to higher education and for implementing change. This article focuses on the…

  19. Spring black stem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spring black stem is the most destructive alfalfa diseases in temperate regions of the U.S., Canada, Australia, and countries of Europe, Asia, and South America. The disease causes serious yield losses by reducing canopy dry matter and also decreases seed weight and crown and root mass. Forage qua...

  20. STEM Sense and Nonsense

    ERIC Educational Resources Information Center

    Charette, Robert N.

    2015-01-01

    If you can believe the daily flood of mass media stories, journal articles, and white papers, the United States is facing a STEM worker crisis. Business leaders and politicians warn that the nation is falling hopelessly behind in the global economic race because our students are unprepared for and uninterested in science, technology, engineering,…

  1. Epithelial Cells Stem Cells

    E-print Network

    Schüler, Axel

    Keywords Epithelial Cells Keratins Stem Cells » Prof. Thomas M. Magin Epithelia protect the body, altered cell adhesion and signal- ling. As no molecular therapy for these conditions is available, one that the co-chaperone CHIP can remove mutant aggregated keratins in a cell culture model of EBS, leading

  2. STEMMING the Gap

    ERIC Educational Resources Information Center

    Kahler, Jim; Valentine, Nancy

    2011-01-01

    America has a gap when it comes to youth pursuing science and technology careers. In an effort to improve the knowledge and application of science, technology, engineering, and math (STEM), after-school programs can work in conjunction with formal in-school curriculum to improve science education. One organization that actively addresses this…

  3. Embryonic Stem Cells

    NSDL National Science Digital Library

    Erdmann, Deanne

    2006-07-20

    BioEd Online is an "educational resource for educators, students, and parents" from the Baylor College of Medicine. This is an excellent place to find educational materials and current information in the field of biology. The "Hot Topics" section of this site focus on current events and issues in biology that are "receiving national attention." The controversy surrounding embryonic stem cells, and coverage it receives in news and research publications in the United States and around the world definitely warrants a closer look at this issue. This "Hot Topic" compiled by Joseph Marx, PhD, Nancy Moreno, PhD, and Deanne Erdmann, MS, contains a brief discussion of the stem cell debate, and includes references and links for further reading. Related news articles can be found as well. Be sure to check out the related slide sets for both embryonic stem cells and stem cells. These slide shows are an excellent resource to use in the classroom. Just add the slides you wish to use to your tray and then view or download your slide tray for an instant visual resource.

  4. Salicylic acid-mediated establishment of the compatibility between Alternaria brassicicola and Brassica juncea is mitigated by abscisic acid in Sinapis alba.

    PubMed

    Mazumder, Mrinmoy; Das, Srirupa; Saha, Upala; Chatterjee, Madhuvanti; Bannerjee, Kaushik; Basu, Debabrata

    2013-09-01

    This work addresses the changes in the phytohormonal signature in the recognition of the necrotrophic fungal pathogen Alternaria brassicicola by susceptible Brassica juncea and resistant Sinapis alba. Although B. juncea, S. alba and Arabidopsis all belong to the same family, Brassicaceae, the phytohormonal response of susceptible B. juncea towards this pathogen is unique because the latter two species express non-host resistance. The differential expression of the PR1 gene and the increased level of salicylic acid (SA) indicated that an SA-mediated biotrophic mode of defence response was triggered in B. juncea upon challenge with the pathogen. Compared to B. juncea, resistant S. alba initiated enhanced abscisic acid (ABA) and jasmonic acid (JA) responses following challenge with this pathogen, as revealed by monitoring the expression of ABA-related genes along with the concentration of ABA and JA. Furthermore, these results were verified by the exogenous application of ABA on B. juncea leaves prior to challenge with A. brassicicola, which resulted in a delayed disease progression, followed by the inhibition of the pathogen-mediated increase in SA response and enhanced JA levels. Therefore, it seems that A. brassicicola is steering the defence response towards a biotrophic mode by mounting an SA response in susceptible B. juncea, whereas the enhanced ABA response of S. alba not only counteracts the SA response but also restores the necrotrophic mode of resistance by enhancing JA biosynthesis. PMID:23770593

  5. Seed dormancy breaking diterpenoids, including novel brassicicenes J and K, from fungus Alternaria brassicicola, and their necrotic/apoptotic activities in HL-60 cells.

    PubMed

    Kenmoku, Hiromichi; Takeue, Sayaka; Oogushi, Megumi; Yagi, Yasuyuki; Sassa, Takeshi; Toyota, Masao; Asakawa, Yoshinori

    2014-03-01

    To find new metabolites similar to cotylenins and fusicoccins from the fungus Alternaria brassicicola, screening tests were carried out using the lettuce seed dormancy breaking assay. Activity-guided fractionation of the EtOAc extract from the culture using the assay afforded the isolation of two novel fusicoccane diterpenoids named brassicicenes J (1) and K (2), along with three known brassicicenes A (3), B (4), and F (5). Their structures were elucidated from extensive NMR spectral data and by comparison of these with those reported in the literature. Brassicicenes (1-5) exhibited weak to moderate seed dormancy breaking activities against lettuce seeds in the presence of abscisic acid. In addition, the necrotic/apoptotic activities of the brassicicenes (1-5), fusicoccin A (6) and cotylenin A (7) were evaluated by determining their cytotoxicity, cell viability and caspase-3/7 activation on the HL-60 cell line. Brassicicene K (2) exhibited similar cytostatic profiles to that of cotylenin A (7), and brassicicenes J (1), A (3), B (4), and F (5) exhibited necrotic activity. This is the first report of the seed dormancy breaking activity of brassicicenes in plants, and of necrotic/apoptotic activity in mammalian cells. PMID:24689212

  6. Analysis of alternariol and alternariol monomethyl ether on flavedo and albedo tissues of tangerines (Citrus reticulata) with symptoms of alternaria brown spot.

    PubMed

    Magnani, Rodrigo F; De Souza, Gezimar D; Rodrigues-Filho, Edson

    2007-06-27

    A method was developed for the quantification of alternariol and alternariol monomethyl ether on tangerines with and without symptoms of Alternaria brown spot disease. The method employs solid-phase extraction for cleanup, followed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) for detection. This method was validated on flavedo (exocarp or epicarp, exterior yellow peel) and on albedo tissue (mesocarp, interior white peel). An excellent linearity over a range of 0.50-20.0 mg/kg was achieved, with r2 >or= 0.997. The limits of detection (LOD) and quantification (LOQ) were fewer than 0.13 and 0.50 microg/kg, respectively. The relative standard deviations (RSDs) were

  7. EMBRYONIC STEM CELLS/INDUCED PLURIPOTENT STEM CELLS Concise Review: Maturation Phases of Human Pluripotent Stem

    E-print Network

    George, Steven C.

    maturity? How well do hPS-CM model embryonic or adult CM in vitro? How does maturity change during in vitroEMBRYONIC STEM CELLS/INDUCED PLURIPOTENT STEM CELLS Concise Review: Maturation Phases of Human · In vitro cell culture · Maturity ABSTRACT Human pluripotent stem cell-derived cardiomyocytes (hPS-CM) may

  8. [Perinatal sources of stem cells].

    PubMed

    Piskorska-Jasiulewicz, Magdalena Maria; Witkowska-Zimny, Ma?gorzata

    2015-01-01

    Recently, stem cell biology has become an interesting topic. Several varieties of human stem cells have been isolated and identified in vivo and in vitro. Successful application of hematopoietic stem cells in hematology has led to the search for other sources of stem cells and expanding the scale of their application. Perinatal stem cells are a versatile cell population, and they are interesting for both scientific and practical objectives. Stem cells from perinatal tissue may be particularly useful in the clinic for autologous transplantation for fetuses and newborns, and after banking in later stages of life, as well as for in utero transplantation in the case of genetic disorders. In this review paper we focus on the extraction and therapeutic potential of stem cells derived from perinatal tissues such as the placenta, the amnion, amniotic fluid, umbilical cord blood and Wharton's jelly. PMID:25748624

  9. Materials as stem cell regulators

    NASA Astrophysics Data System (ADS)

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-06-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine.

  10. TPCP: Cryphonectria canker of Eucalyptus CRYPHONECTRIA CANKER OF

    E-print Network

    in various parts of the world such as Brazil and India. The disease was discovered in South Africa in 1988 of the world such as Brazil. Sexual spores of Cryphonectria cubensis. MANAGEMENT STRATEGIES The most effective. This fungus is soil borne and infects roots leading to a girdling of the bases of young trees. Trees, infected

  11. Spatial pattern analysis of citrus canker-infected plantings in são paulo, Brazil, and augmentation of infection elicited by the asian leafminer.

    PubMed

    Gottwald, T R; Bassanezi, R B; Amorim, L; Bergamin-Filho, A

    2007-06-01

    ABSTRACT Eradication of Asiatic citrus canker (ACC) has become increasingly difficult over the last decade, following the introduction of the Asian leafminer into Brazil and Florida, which has led to changes in the eradication protocols. The present study, undertaken in Brazil, was aimed at characterizing the spatial patterns of ACC in commercial citrus plantings to gain better understanding of the dynamics of the disease subsequent to introduction of the leafminer. The spatial patterns of ACC were mapped in 326 commercial citrus plantings and statistically assessed at various spatial dimensions. The presence of "within-group" aggregation in each plot was examined via beta-binomial analysis for groups of trees parsed into three-by-three-tree quadrats. The relative intensity of aggregation was expressed as a binomial index of dispersion (D) and heterogeneity among plots expressed as the intracluster correlation coefficient, rho. The population of data sets was found to fall into three D categories, D < 1.3, 1.3 3.5. These categories then were related to other spatial characteristics. The binary form of Taylor's power law was used to assess the overdispersion of disease across plots and was highly significant. When the overall population of plots was parsed into D categories, the Taylor's R (2) improved in all cases. Although these methods assessed aggregation well, they do not give information on the number of foci or aggregations within each plot. Therefore, the number of foci per 1,000 trees was quantified and found to relate directly to the D categories. The lowest D category could be explained by a linear relationship of number of foci versus disease incidence, whereas the higher two categories were most easily explained by a generalized beta function for the same relationship. Spatial autocorrelation then was used to examine the spatial relationships "among groups" composed of three-by-three-tree quadrats and determine common distances between these groups of ACC-infected trees. Aggregation was found in >84% of cases at this spatial level and there was a direct relationship between increasing D category and increasing core cluster size, and aggregation at the among-group spatial hierarchy was generally stronger for the within-row than for the across-row orientation. Clusters of disease were estimated to average between 18 and 33 tree spaces apart, and the presence of multiple foci of infection was commonplace. The effectiveness of the eradication protocol of removing all "exposed" trees within 30 m surrounding each "ACC-infected tree" was examined, and the distance of subsequent infected trees beyond this 30-m zone from the original focal infected tree was measured for each plot. A frequency distribution was compiled over all plots to describe the distance that would have been needed to circumscribe all of these outliers as a theoretical alternative protocol to the 30-m eradication protocol. The frequency distribution was well described by a monomolecular model (R(2) = 0.98) and used to determine that 90, 95, and 99% of all newly infected trees occurred within 296, 396, and 623 m of prior-infected trees in commercial citrus plantings, respectively. These distances are very similar to previously reported distances determined for ACC in residential settings in Florida. PMID:18943598

  12. STEM Equity Pipeline

    NSDL National Science Digital Library

    As a past president of the National Academy of Engineering put it, "A consequence of lack of diversity...[is that] we pay an opportunity cost, a cost in designs not thought of, in solutions not produced." Thus, in an effort to increase the diversity of the Science, Technology, Engineering and Mathematics (STEM) workforce, STEM Equity Pipeline was developed. The "Online Resources" section of their website offers visitors a wide variety of resources, including "pamphlets/brochures", "posters", "scholarships" and "videos". The "Curriculum" resource is particularly rich and it offers over 50 websites that contain single activities, whole lesson plans or hands-on explorations. Some of the titles visitors might find valuable are "Some Disassembly Required", which employs reverse engineering (or taking things apart) to learn how they work, "Teaching Tool for Introductory Programming Concepts", to teach students computer programming in a 3D environment, and "Home Science Adventures", science lessons and plans for home- schoolers.

  13. Stem cell quest.

    PubMed

    Irvine, Alexandra

    2015-03-01

    Chronic Myeloid Leukaemia has been a valuable model system for experimental haematologists for many years. Virtually all patients (>95 %) have the same genetic change which has driven the development of the first targeted therapies, tyrosine kinase inhibitors (TKIs). Since the introduction of TKIs in 2000 it has become clear that this approach has significantly improved the outcome for these patients. Nevertheless drug resistance inevitably develops and it is clear that the disease is controlled rather than eradicated. The recent publication by Herrmann et al. has defined a sub-population of leukaemic stem cells which are responsible for propagating the disease. CD26 now provides a new specific target for the malignant stem cells and offers the possibility of true curative therapy. PMID:25698663

  14. Neural stem cells.

    PubMed

    Kennea, Nigel L; Mehmet, Huseyin

    2002-07-01

    Neural stem cells (NSCs) have the ability to self-renew, and are capable of differentiating into neurones, astrocytes and oligodendrocytes. Such cells have been isolated from the developing brain and more recently from the adult central nervous system. This review aims to provide an overview of the current research in this evolving area. There is now increasing knowledge of the factors controlling the division and differentiation of NSCs during normal brain development. In addition, the cues for differentiation in vitro, and the possibility of transdifferentiation are reviewed. The discovery of these cells in the adult brain has encouraged research into their role during neurogenesis in the normal mature brain and after injury. Lastly other sources of neural precursors are discussed, and the potential for stem cells to be used in cell replacement therapy for brain injury or degenerative brain diseases with a particular emphasis on cerebral ischaemia and Parkinson's disease. PMID:12115869

  15. Breast Cancer Stem Cells

    PubMed Central

    Velasco-Velázquez, Marco A.; Homsi, Nora; De La Fuente, Marisol; Pestell, Richard G.

    2012-01-01

    Breast cancer stem cells (BCSCs) constitute a subpopulation of tumor cells that express stem cell-associated markers and have a high capacity for tumor generation in vivo. Identification of BCSCs from tumor samples or breast cancer cell lines has been based mainly on CD44+/CD24?/low or ALDH+ phenotypes. BCSCs isolation has allowed the analysis of the molecular mechanisms involved in their origin, self-renewal, differentiation into tumor cells, resistance to radiation therapy and chemotherapy, and invasiveness and metastatic ability. Molecular genetic analysis using knockout animals and inducible transgenics have identified NF-?B, c-Jun, p21CIP1, and Forkhead-like-protein Dach1 in BCSC expansion and fate. Clinical analyses of BCSCs in breast tumors have found a correlation between the proportion of BCSCs and poor prognosis. Therefore, new therapies that specifically target BCSCs are an urgent need. We summarize recent evidence that partially explain the biological characteristics of BCSCs. PMID:22249027

  16. Melanocytes, melanocyte stem cells, and melanoma stem cells

    PubMed Central

    Lang, Deborah; Mascarenhas, Joseph B.; Shea, Christopher R.

    2012-01-01

    Melanocyte stem cells differ greatly from melanoma stem cells; the former provide pigmented cells during normal tissue homeostasis and repair, while the latter play an active role in a lethal form of cancer. These two cell types share several features and can be studied by similar methods. Aspects held in common by both melanocyte stem cells and melanoma stem cells include their expression of shared biochemical markers, a system of similar molecular signals necessary for their maintenance, and a requirement for an ideal niche microenvironment for providing these factors. This review provides a perspective of both these cell types and discusses potential models of stem cell growth and propagation. Recent findings provide a strong foundation for the development of new therapeutics directed at isolating and manipulating melanocyte stem cells for tissue engineering or at targeting and eradicating melanoma specifically, while sparing non-tumor cells. PMID:23438380

  17. Spermatogonial Stem Cells

    Microsoft Academic Search

    Dirk G. de Rooij

    \\u000a New developments in the field of spermatogonial stem cell (SSC) research have been reviewed. Novel techniques have rendered\\u000a interesting results in studies on SSC kinetics in nonprimate mammals as well as in primates, and the classical views on the\\u000a nature and the behavior of SSC are being challenged. However, no definite conclusions can yet be drawn. Many new proteins\\u000a have

  18. AccessSTEM

    NSDL National Science Digital Library

    The University of Washington's award-winning DO-IT Center (Disabilities, Opportunities, Internetworking and Technology) collaborates with AccessSTEM, which has been funded by the National Science Foundation since 2002. AccessSTEM, aims to "broaden participation in STEM fields and improve those fields with the perspectives and expertise of people with disabilities." Visitors to the site who are disabled students, faculty, employees, or just the interested public will find much to peruse or read in-depth. There is the longitudinal transition study link in the "For Faculty and Employees" section that tracks the college and career paths of students with disabilities who used the DO-IT program. Visitors will find the "Promising Practices" section, also in the Faculty and Employees section, to be filled with useful articles and innovations. There is "A Smart Board in the Classroom: A Promising Practice for Engaging Students", which addresses how the use of a Smart Board can aid students with attention deficits, visual impairments, and other disabling conditions without bringing the whole class' attention to them.

  19. Biomaterials as Stem Cell Niche: Cardiovascular Stem Cells

    Microsoft Academic Search

    Ge Zhang; Laura J. Suggs

    \\u000a A tissue-specific stem cell niche functions to direct either self-renewal or differentiation. The niche comprises all local\\u000a cues that can be sensed by the cell including soluble and insoluble signals, physical forces and cell–cell contacts. Approximating\\u000a the stem cell niche through the utilization of biomaterials may give rise to a greater understanding of the biology of the\\u000a stem cell niche

  20. Horizontal gene transfer and gene dosage drives adaptation to wood colonization in a tree pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some of the most damaging tree pathogens can attack woody stems, causing lesions (cankers) that may be lethal. To identify the genomic determinants of wood colonization leading to canker formation, we sequenced the genomes of the poplar canker pathogen, Mycosphaerella populorum, and the closely rela...

  1. Cancer Stem Cells in Breast

    PubMed Central

    Charafe-Jauffret, Emmanuelle; Monville, Florence; Ginestier, Christophe; Dontu, Gabriela; Birnbaum, Daniel; Wicha, Max S.

    2009-01-01

    There is increasing evidence for the cancer stem cell hypothesis, which holds that cancers are driven by a cellular subcomponent that has stem cell properties, that is, self-renewal, tumorigenicity and multilineage differentiation capacity. The cancer stem cell hypothesis modifies our conceptual approach of oncogenesis and shall have implications in breast cancer prevention, detection and treatment, especially in metastatic breast cancer for which no curative treatment exists. Given the specific stem cell features, novel therapeutic pathways can be targeted. Following this approach, new molecules are currently in development. Focusing on the cross-talk between stem cells and their microenvironment is also a promising way to explore how to better target cancer stem cells and be curative. PMID:18544962

  2. Stem cells in gastroenterology and hepatology

    Microsoft Academic Search

    Michael Quante; Timothy C. Wang

    2009-01-01

    Cellular and tissue regeneration in the gastrointestinal tract and liver depends on stem cells with properties of longevity, self-renewal and multipotency. Progress in stem cell research and the identification of potential esophageal, gastric, intestinal, colonic, hepatic and pancreatic stem cells provides hope for the use of stem cells in regenerative medicine and treatments for disease. Embryonic stem cells and induced

  3. Stem Cell Basics About this document

    E-print Network

    Bandettini, Peter A.

    1 Stem Cell Basics About this document This primer on stem cells is intended for anyone who wishes to learn more about the biological properties of stem cells, the important questions about stem cells that are the focus of scientific research, and the potential use of stem cells in research and in treating disease

  4. Embryonic Stem Cells Cell Signalling Course

    E-print Network

    South Bohemia, University of

    Embryonic Stem Cells Cell Signalling Course Ceské Budjovice January 2013 #12;Pluripotent (stem(s) of differentiation ·Symmetric/asymmetric division ? ? ? ? #12;Where can we find the origins of stem cell research;1981 Lines of pluripotent cells were established for the first time from mouse embryo ­ Embryonic Stem Cells

  5. Embryonic Stem Cells Cell Signalling Course

    E-print Network

    South Bohemia, University of

    Embryonic Stem Cells Cell Signalling Course Ceské Budjovice November 2013 #12;Pluripotent (stem(s) of differentiation ·Symmetric/asymmetric division ? ? ? ? #12;Where can we find the origins of stem cell research;1981 Lines of pluripotent cells were established for the first time from mouse embryo ­ Embryonic Stem Cells

  6. Adult Stem and Progenitor Cells

    Microsoft Academic Search

    Martine Geraerts; Catherine M. Verfaillie

    2009-01-01

    \\u000a The discovery of adult stem cells in most adult tissues is the basis of a number of clinical studies that are carried out,\\u000a with therapeutic use of hematopoietic stem cells as a prime example. Intense scientific debate is still ongoing as to whether\\u000a adult stem cells may have a greater plasticity than previously thought. Although cells with some features of

  7. Marrow Stromal Mesenchymal Stem Cells

    Microsoft Academic Search

    Cynthia B. Ripoll; Bruce A. Bunnell

    \\u000a The broad definition of a stem cell is a population of cells that has the ability to self-renew and to differentiate into\\u000a one or more types of specialized terminally differentiated cells. It has become evident that stem cells persist in and can\\u000a be isolated from many organs postnatally. Stem cells isolated from various sources have been demonstrated to vary in

  8. Stem cells in veterinary medicine

    Microsoft Academic Search

    Lisa A Fortier; Alexander J Travis

    2011-01-01

    The stem cell field in veterinary medicine continues to evolve rapidly both experimentally and clinically. Stem cells are\\u000a most commonly used in clinical veterinary medicine in therapeutic applications for the treatment of musculoskeletal injuries\\u000a in horses and dogs. New technologies of assisted reproduction are being developed to apply the properties of spermatogonial\\u000a stem cells to preserve endangered animal species. The

  9. Stem Cell Transplants at Childbirth

    Microsoft Academic Search

    Paul R. Sanberg; Dong-Hyuk Park; Cesar V. Borlongan

    2010-01-01

    Autologous transplantation of stem cells is a natural phenomenon at birth in mammals via the umbilical cord. Here, we discuss\\u000a that a delay in the cord clamping may increase stem cell supply to the baby, thereby allowing an innate stem cell therapy\\u000a that can render acute benefits in the case of neonatal disease, as well as long-term benefits against age-related

  10. The YAP1 homolog-mediated oxidative stress tolerance is crucial for pathogenicity of the necrotrophic fungus Alternaria alternata in citrus.

    PubMed

    Lin, Ching-Hsuan; Yang, Siwy Ling; Chung, Kuang-Ren

    2009-08-01

    Citrus brown spot disease is caused by the necrotrophic fungus Alternaria alternata. Its pathogenic capability has been thought to depend exclusively on the production of host-selective ACT toxin. However, circumvention of plant defenses is also likely to be important for the disease process. To investigate the fungal response to host-generated reactive oxygen species (ROS), we cloned and characterized the AaAP1 gene of A. alternata, which encodes a polypeptide resembling yeast YAP1-like transcriptional activators implicated in cellular responses to stress. Expression of the AaAP1 gene in a wild-type strain was primarily induced by H(2)O(2) or ROS-generating oxidants. Using a loss-of-function mutation in the AaAP1 gene, we demonstrated an essential requirement for oxidative tolerance during the host invasion step. Mutants lacking AaAP1 showed increased sensitivity to H(2)O(2) and loss of fungal pathogenicity. The DeltaAaAP1 null mutant did not cause any visible necrotic lesions on wounded or unwounded leaves of citrus cv. Minneola. Compared with the wild type, the null mutant displayed lower catalase, peroxidase, and superoxide dismutase activities. All mutant phenotypes were restored to the wild type in fungal strains expressing a functional copy of AaAP1. Upon exposure to H(2)O(2), the AaAP1::sGFP (synthetic green fluorescent protein) fusion protein became localized in the nucleus. Inoculation of the mutant with NADPH oxidase inhibitors partially restored fungal pathogenicity. Our results highlight the global regulatory role of a YAP1 homolog in response to oxidative stress in A. alternata and provide insights into the critical role of ROS detoxification in the pathogenicity of A. alternata. PMID:19589070

  11. iSeek: STEM Careers

    NSDL National Science Digital Library

    Minnesota's iSeek website "works with the state's workforce development and education authorities to develop and inform policy and to strategize services for career planning, education and e-learning, and workforce development." But the resources on the STEM Careers and Skills section of the site aren't just for those people living in Minnesota; this section provides all visitors the opportunity to explore STEM career skills that can be helpful no matter what state they live in. Visitors interested in learning what STEM skills are, should check out the link "Understanding STEM Skills". Here key STEM skills are outlined, such as analytical skills, science skills, technical, and math skills. The site also goes on to outline some of the soft skills that those in STEM careers should have, such as leadership, organization, communication, and creative skills. Visitors can take a free 5-10 minute "Skills Assessment" to determine which of their interests and skills match up with STEM careers. The "STEM Careers" link has a list of high-demand STEM careers, average hourly wage, and typical education requirements.

  12. Human Embryonic Stem Cell Registry

    NSDL National Science Digital Library

    The National Institutes of Health (NIH) has recently released the Human Embryonic Stem Cell Registry in response to the President's announcement on August 9, 2001 to allow federal funds for stem cell research. The site lists the eleven laboratories or companies that meet the specific criteria for approved stem cell lines and explains the criteria themselves. The NIH gives the number of actual lines for each entity, the NIC and providers code for each, as well as contact information. The Website also provides links to those seeking additional information about NIH stem cell information, grants and funding opportunities, technology transfer issues, and further facts about the NIH.

  13. STEm Minority Graduate Program

    SciTech Connect

    Kaen E. Nicholas

    2012-09-20

    ABSTRACT The state of science, technology, engineering and math (STEM) education in the United States has seen some unfavorable assessments over the past decade. In early February, 2010 the House of Representatives heard testimony on undergraduate and graduate education. The message from the panel, which included experts from academia, STEM-based industries, and the National Science Foundation (NSF) was dire and required an urgent response. The experts along with the committee���¢��������s chairperson, U. S. Representative Daniel Lipinski (D-IL) cited that the complexity of Science, Technology, Engineering, and Mathematics applications and coursework and the methodology utilized to teach these subjects are forcing students out of these disciplines. As the National Academies described in its 2007 report Rising Above the Gathering Storm, successful STEM education is not just an academic pursuit���¢��������it���¢��������s a necessity for competing in the knowledge-based economy that the United States had a key role in creating. The potential for action is being made available again as the America COMPETES Act of 2007 is up for reauthorization. Its initial focus was on STEM education at the K-12 levels, but efforts at the undergraduate and graduate levels are needed to retain students to fill the jobs left vacant as baby boomers retire. The Educational Advancement Alliance, Inc. (EAA) has for two decades created programs that have not only addressed the issues of ensuring that students are aptly prepared for college but have focused its efforts over the past decade on increasing the number of students who pursue degrees in STEM disciplines. For the EAA, the introduction of the wonders of science begins at the elementary and middle school level via the Learning Lab, a state-of-the-art mobile science laboratory that visits students in grades 4-6 at the various schools throughout Philadelphia and The Math/Tech Academy which meets on Saturdays for students in grades 5-7. For the past two years the EAA has assisted college graduates in their quest to attain advanced degrees in STEM by providing fellowships. The EAA continued this effort by recruiting and providing fellowships to students who aspired to continue their education at the graduate level. The fellowships provided funding for tuition, fees, books, technology, and stipends to assist with room, board, and living expenses during the academic year and salary, transportation, and living expenses to those students who secured internships with the Department of Energy. Additionally the EAA designed and implemented needed support systems to ensure successful completion of the Masters degree programs, including but not limited to membership in professional associations, attendance at industry and academic conferences, and professional development workshops, and tutorial assistance if needed. This program assisted over 80 students directly and society-at-large by helping to educate and develop future physicists, engineers, biostatisticians, and researchers who will have the necessary skillsets to fill the increasing numbers of positions that require such expertise.

  14. Learning for STEM Literacy: STEM Literacy for Learning

    ERIC Educational Resources Information Center

    Zollman, Alan

    2012-01-01

    We are in the STEM generation whose comprehensive purpose is to resolve (1) societal needs for new technological and scientific advances; (2) economic needs for national security; and (3) personal needs to become a fulfilled, productive, knowledgeable citizen. STEM specifically refers to science, technology, engineering, and mathematics, but now…

  15. Are STEM High School Students Entering the STEM Pipeline?

    ERIC Educational Resources Information Center

    Franco, M. Suzanne; Patel, Nimisha H.; Lindsey, Jill

    2012-01-01

    This study compared the career skills and interests for students in two STEM schools to national data. Students completed the KUDER skills assessment and career planning online tools. Results were compared across school, grade level, and sex. The results provided evidence that STEM high school students expressed career intents in predominately…

  16. 6. VIEW SHOWING UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE, WITH LOG ACCESS STRUCTURE, LOOKING WEST - High Mountain Dams in Upalco Unit, Bluebell Lake Dam, Ashley National Forest, 11.2 miles Northwest of Swift Creek Campground, Mountain Home, Duchesne County, UT

  17. 5. VIEW SHOWING UPRIGHT OUTLET GATE WHEEL, STEM AND STEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW SHOWING UPRIGHT OUTLET GATE WHEEL, STEM AND STEM GUIDE, WITH LOG ACCESS STRUCTURE, LOOKING SOUTHEAST - High Mountain Dams in Upalco Unit, Bluebell Lake Dam, Ashley National Forest, 11.2 miles Northwest of Swift Creek Campground, Mountain Home, Duchesne County, UT

  18. Advancing the STEM Workforce through STEM-Centric Career Development

    ERIC Educational Resources Information Center

    Feller, Rich

    2011-01-01

    Preparing for the future is not what it used to be. Yet, advising students, preparing lessons, and promoting the value of STEM options remains constant. As a result, technical and engineering educators seek clarity about the future of careers, career development, and ways to promote STEM options. Recently, the ITEEA conference allowed the author…

  19. 7 CFR 29.6039 - Stem rot.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 2011-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action....

  20. 7 CFR 29.6039 - Stem rot.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action....

  1. 7 CFR 29.6039 - Stem rot.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 2010-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action....

  2. 7 CFR 29.6039 - Stem rot.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action....

  3. 7 CFR 29.6039 - Stem rot.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action....

  4. Skeletal stem cells.

    PubMed

    Bianco, Paolo; Robey, Pamela G

    2015-03-15

    Skeletal stem cells (SSCs) reside in the postnatal bone marrow and give rise to cartilage, bone, hematopoiesis-supportive stroma and marrow adipocytes in defined in vivo assays. These lineages emerge in a specific sequence during embryonic development and post natal growth, and together comprise a continuous anatomical system, the bone-bone marrow organ. SSCs conjoin skeletal and hematopoietic physiology, and are a tool for understanding and ameliorating skeletal and hematopoietic disorders. Here and in the accompanying poster, we concisely discuss the biology of SSCs in the context of the development and postnatal physiology of skeletal lineages, to which their use in medicine must remain anchored. PMID:25758217

  5. STEM Careers Exploration

    NSDL National Science Digital Library

    This activity includes a presentation with links to videos about scientists and engineers working with NASA's Global Precipitation Measurement Mission (from the Faces of GPM series), as well as other STEM careers videos, followed by a number of links to online career resources. It is designed to be used by students working at their own pace, choosing which videos and links they are interested in watching and exploring, but could also be used with a larger group. As part of the activity, students identify personal skills and abilities related to career interests and develop a career goal. Includes a student capture sheet with guiding questions.

  6. Stem Cell Research

    SciTech Connect

    Catherine Verfaillie

    2009-01-23

    We have identified a population of primitive cells in normal human post-natal bone marrow that can, at the single cell level, differentiate in many ways and also proliferate extensively. These cells can differentiate in vitro into most mesodermal cell types (for example, bone cells, and others), as well as cells into cells of the nervous system. The finding that stem cells exist in post-natal tissues with previously unknown proliferation and differentiation potential opens up the possibility of using them to treat a host of degenerative, traumatic or congenital diseases.

  7. Stem Cell Glycolipids

    Microsoft Academic Search

    Makoto Yanagisawa

    Glycolipids are compounds containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety.\\u000a Because of their expression patterns and the intracellular localization patterns, glycolipids, including stage-specific embryonic\\u000a antigens (SSEA-3, SSEA-4, and possibly SSEA-1) and gangliosides (e.g., GD3, GD2, and A2B5 antigens), have been used as marker\\u000a molecules of stem cells. In this review, I will

  8. Adult skeletal muscle stem cells.

    PubMed

    Sambasivan, Ramkumar; Tajbakhsh, Shahragim

    2015-01-01

    Skeletal muscles in vertebrates have a phenomenal regenerative capacity. A muscle that has been crushed can regenerate fully both structurally and functionally within a month. Remarkably, efficient regeneration continues to occur following repeated injuries. Thousands of muscle precursor cells are needed to accomplish regeneration following acute injury. The differentiated muscle cells, the multinucleated contractile myofibers, are terminally withdrawn from mitosis. The source of the regenerative precursors is the skeletal muscle stem cells-the mononucleated cells closely associated with myofibers, which are known as satellite cells. Satellite cells are mitotically quiescent or slow-cycling, committed to myogenesis, but undifferentiated. Disruption of the niche after muscle damage results in their exit from quiescence and progression towards commitment. They eventually arrest proliferation, differentiate, and fuse to damaged myofibers or make de novo myofibers. Satellite cells are one of the well-studied adult tissue-specific stem cells and have served as an excellent model for investigating adult stem cells. They have also emerged as an important standard in the field of ageing and stem cells. Several recent reviews have highlighted the importance of these cells as a model to understand stem cell biology. This chapter begins with the discovery of satellite cells as skeletal muscle stem cells and their developmental origin. We discuss transcription factors and signalling cues governing stem cell function of satellite cells and heterogeneity in the satellite cell pool. Apart from satellite cells, a number of other stem cells have been shown to make muscle and are being considered as candidate stem cells for amelioration of muscle degenerative diseases. We discuss these "offbeat" muscle stem cells and their status as adult skeletal muscle stem cells vis-a-vis satellite cells. The ageing context is highlighted in the concluding section. PMID:25344672

  9. Gastrointestinal stem cell up-to-date

    PubMed Central

    Pirvulet, V

    2015-01-01

    Cellular and tissue regeneration in the gastrointestinal tract depends on stem cells with properties of self-renewal, clonogenicity, and multipotency. Progress in stem cell research and the identification of potential gastric, intestinal, colonic stem cells new markers and the signaling pathways provide hope for the use of stem cells in regenerative medicine and treatments for disease. This review provides an overview of the different types of stem cells, focusing on tissue-restricted adult stem cells. PMID:25866586

  10. Stem cell differentiation: Multipotency retained

    NASA Astrophysics Data System (ADS)

    Mrksich, Milan

    2011-08-01

    Stem cells that are cultured in the laboratory differentiate in response to the mechanical properties of the substrate and its topography. It is now shown that mesenchymal stem cell multipotency is prolonged when the cells are cultured on a surface patterned with an ordered arrangement of nanoscale pits.

  11. Excising the Root from STEM

    ERIC Educational Resources Information Center

    Lock, Roger

    2009-01-01

    There are a number of well-intentioned STEM initiatives, some designed to improve the recruitment and retention of science teachers. Sometimes it appears that the initiators are remote from direct contact with the "grass roots" issues that feed the "stem" on which the blossoms of young enthusiastic recruits to the science teaching profession are…

  12. Building STEM Opportunities for All

    ERIC Educational Resources Information Center

    Lynch, Sharon J.; Peters-Burton, Erin; Ford, Michael

    2015-01-01

    In response to a report from the President's Council of Advisors on Science and Technology, President Obama issued a challenge to the U.S. education system to create more than 1,000 new STEM-focused schools, including 200 high schools. Inclusive STEM-focused high schools--which focus their efforts on females, minorities, and students who are…

  13. Engaging Students in STEM Education

    ERIC Educational Resources Information Center

    Kennedy, T. J.; Odell, M. R. L.

    2014-01-01

    With the "flattening" of the global economy in the 21st century, the teaching of Science, Technology, Engineering, and Mathematics (STEM) has taken on new importance as economic competition has become truly global. STEM education has evolved into a meta-discipline, an integrated effort that removes the traditional barriers between these…

  14. STEM: Science Technology Engineering Mathematics

    ERIC Educational Resources Information Center

    Carnevale, Anthony P.; Smith, Nicole; Melton, Michelle

    2011-01-01

    The generative economic power and social influence of Science, Technology, Engineering, and Mathematics (STEM) has made the production of a capable science and engineering workforce a priority among business and policy leaders. They are rightly concerned that without a robust STEM workforce, the nation will become less competitive in the global…

  15. Plasticity of Adult Stem Cells

    Microsoft Academic Search

    Amy J Wagers; Irving L Weissman

    2004-01-01

    Recent years have seen much excitement over the possibility that adult mammalian stem cells may be capable of differentiating across tissue lineage boundaries, and as such may represent novel, accessible, and very versatile effectors of therapeutic tissue regeneration. Yet studies proposing such “plasticity” of adult somatic stem cells remain controversial, and in general, existing evidence suggests that in vivo such

  16. Stem cells in the eye

    Microsoft Academic Search

    Mike Boulton; Julie Albon

    2004-01-01

    In the adult organism, all tissue renewal and regeneration depends ultimately on somatic stem cells, and the eye is no exception. The importance of limbal stem cells in the maintenance of the corneal epithelium has long been recognised, and such cells are now used clinically for repair of a severely damaged cornea. The slow cycling nature of lens epithelial cells

  17. Cell Stem Cell Short Article

    E-print Network

    Collins, James J.

    -renewal and reprogramming. INTRODUCTION The transcription factors OCT4, NANOG, and SOX2 are master regulators of pluripotency in embryonic stem cells (ESCs) (De Los Angeles et al., 2012) and, along with Klf4 and c the requirement of OCT4, SOX2, and NANOG in stem cell function (De Los Angeles et al., 2012), discrepancies

  18. Hip stem fatigue test prediction

    Microsoft Academic Search

    Heidi-Lynn Ploeg; Maja Bürgi; Urs P. Wyss

    2009-01-01

    The accuracy of fatigue test prediction methods for the standard fatigue testing of hip stems was evaluated against the experimental results of static and fatigue tests. Axial unnotched strain-controlled material fatigue tests provided the required cyclic material properties. Finite element analysis of the hip stems predicted a maximum tensile stress to within 3–7% of strain gauge measurements. The four methods

  19. Stem Cells in Aging

    PubMed Central

    Yunis, Edmond J.; Zúñiga, Joaquin; Koka, Prasad S.; Husain, Zaheed; Romero, Viviana; Stern, Joel N.H.; Fridkis-Hareli, Masha

    2008-01-01

    Aging is a genetically programmed decline in the functional effectiveness of the organism. It is manifested by a collective group of changes in cells or organs that occur over the course of a lifespan, limiting the duration of life. Longevity usually refers to long-lived members of a population within species. Organs develop and can involute according to specific timetables. Such timetables correlate with a preordained proliferative capacity of cells mediated by cell and organ clocks. In this review, we discuss different aspects related to genetic and environmental factors that are involved in determining life span. We discuss the influence of ontogenic, genetic and environmental factors in aging. The genetic factors can be studied in embryonic stem cells (ESC) and in niches (microenvironments) of stem cells (SC) using cellular or experimental animal models. We discuss molecular mechanisms involving genes and proteins associated with death pathways, niches, or hubs, on longevity. Moreover, we also discuss genes and proteins, associated with death pathways, on longevity. Unraveling these mechanisms may further our understanding of human aging leading to development of therapeutic interventions with the potential of prolonging life. PMID:19030125

  20. Engineering stem cells for therapy.

    PubMed

    Mendez-Pertuz, Marinela; Hughes, Chris; Annenkov, Alex; Daly, Gordon; Chernajovsky, Yuti

    2006-07-01

    The differentiation of a stem cell is dependent on the environmental cues that it receives and can be modulated by the expression of different master regulators or by secreted factors or inducers. The use of genetically modified stem cells to express the required factors can direct differentiation along the requisite pathway. This approach to the engineering of stem cells is important, as control of the pluripotentiality of stem cells is necessary in order to avoid unwanted growth, migration or differentiation to nontarget tissues. The authors provide an overview of the stem cell engineering field, highlighting challenges and solutions, and focusing on recent developments in therapeutic applications in areas such as autoimmunity, CNS lesions, bone and joint diseases, cancer and myocardial infarction. PMID:17465851

  1. Bi-stem gripping apparatus

    NASA Technical Reports Server (NTRS)

    Sanders, Fred G. (inventor)

    1988-01-01

    This invention relates to devices which grip cylindrical structures and more particularly to a device which has three arcuate gripping members having frictional surfaces for gripping and compressing a bi-stem. The bi-stem gripping apparatus is constructed having a pair of side gripping members, and an intermediate gripping member disposed between them. Sheets of a gum stock silicone rubber with frictional gripping surfaces are bonded to the inner region of the gripping members and provide frictional engagement between the bi-stem and the apparatus. A latch secures the gripping apparatus to a bi-stem, and removable handles are attached, allowing an astronaut to pull the bi-stem from its cassette. A tethering ring on the outside of the gripping apparatus provides a convenient point to which a lanyard may be attached.

  2. Bioprinting for stem cell research

    PubMed Central

    Tasoglu, Savas; Demirci, Utkan

    2012-01-01

    Recently, there has been a growing interest to apply bioprinting techniques to stem cell research. Several bioprinting methods have been developed utilizing acoustics, piezoelectricity, and lasers to deposit living cells onto receiving substrates. Using these technologies, spatially defined gradients of immobilized proteins can be engineered to direct stem cell differentiation into multiple subpopulations of different lineages. Stem cells can also be patterned in a high-throughput manner onto flexible implementation patches for tissue regeneration or onto substrates with the goal of accessing encapsulated stem cell of interest for genomic analysis. Here, we review recent achievements with bioprinting technologies in stem cell research, and identify future challenges and potential applications including tissue engineering and regenerative medicine, wound healing, and genomics. PMID:23260439

  3. Stem Cells behind the Barrier.

    PubMed

    Cangkrama, Michael; Ting, Stephen B; Darido, Charbel

    2013-01-01

    Epidermal stem cells sustain the adult skin for a lifetime through self-renewal and the production of committed progenitors. These stem cells generate progeny that will undergo terminal differentiation leading to the development of a protective epidermal barrier. Whereas the molecular mechanisms that govern epidermal barrier repair and renewal have been extensively studied, pathways controlling stem cell differentiation remain poorly understood. Asymmetric cell divisions, small non-coding RNAs (microRNAs), chromatin remodeling complexes, and multiple differentiation factors tightly control the balance of stem and progenitor cell proliferation and differentiation, and disruption of this balance leads to skin diseases. In this review, we summarize and discuss current advances in our understanding of the mechanisms regulating epidermal stem and progenitor cell differentiation, and explore new relationships for maintenance of skin barrier function. PMID:23812084

  4. Function of genes encoding acyl-CoA synthetase and enoyl-CoA hydratase for host-selective act-toxin biosynthesis in the tangerine pathotype of Alternaria alternata.

    PubMed

    Miyamoto, Y; Ishii, Y; Honda, A; Masunaka, A; Tsuge, T; Yamamoto, M; Ohtani, K; Fukumoto, T; Gomi, K; Peever, T L; Akimitsu, K

    2009-04-01

    The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease. Sequence analysis of a genomic cosmid clone identified a part of the ACTT gene cluster and implicated two genes, ACTT5 encoding an acyl-CoA synthetase and ACTT6 encoding an enoyl-CoA hydratase, in the biosynthesis of ACT-toxin. Genomic Southern blots demonstrated that both genes were present in tangerine pathotype isolates producing ACT-toxin and also in Japanese pear pathotype isolates producing AK-toxin and strawberry pathotype isolates producing AF-toxin. ACT-, AK-, and AF-toxins from these three pathotypes share a common 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid moiety. Targeted gene disruption of two copies of ACTT5 significantly reduced ACT-toxin production and virulence. Targeted gene disruption of two copies of ACTT6 led to complete loss of ACT-toxin production and pathogenicity and a putative decatrienoic acid intermediate in ACT-toxin biosynthesis accumulated in mycelial mats. These results indicate that ACTT5 and ACTT6 are essential genes in ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and both are required for full virulence of this fungus. PMID:19271978

  5. Genetically based location from triploid populations and gene ontology of a 3.3-mb genome region linked to Alternaria brown spot resistance in citrus reveal clusters of resistance genes.

    PubMed

    Cuenca, José; Aleza, Pablo; Vicent, Antonio; Brunel, Dominique; Ollitrault, Patrick; Navarro, Luis

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria alternata. This pathogen produces ACT-toxin, which induces necrotic lesions on fruit and young leaves, defoliation and fruit drop in susceptible genotypes. It is a strong concern for triploid breeding programs aiming to produce seedless mandarin cultivars. The monolocus dominant inheritance of susceptibility, proposed on the basis of diploid population studies, was corroborated in triploid progeny. Bulk segregant analysis coupled with genome scan using a large set of genetically mapped SNP markers and targeted genetic mapping by half tetrad analysis, using SSR and SNP markers, allowed locating a 3.3 Mb genomic region linked to ABS resistance near the centromere of chromosome III. Clusters of resistance genes were identified by gene ontology analysis of this genomic region. Some of these genes are good candidates to control the dominant susceptibility to the ACT-toxin. SSR and SNP markers were developed for efficient early marker-assisted selection of ABS resistant hybrids. PMID:24116149

  6. Genetically Based Location from Triploid Populations and Gene Ontology of a 3.3-Mb Genome Region Linked to Alternaria Brown Spot Resistance in Citrus Reveal Clusters of Resistance Genes

    PubMed Central

    Cuenca, José; Aleza, Pablo; Vicent, Antonio; Brunel, Dominique; Ollitrault, Patrick; Navarro, Luis

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria alternata. This pathogen produces ACT-toxin, which induces necrotic lesions on fruit and young leaves, defoliation and fruit drop in susceptible genotypes. It is a strong concern for triploid breeding programs aiming to produce seedless mandarin cultivars. The monolocus dominant inheritance of susceptibility, proposed on the basis of diploid population studies, was corroborated in triploid progeny. Bulk segregant analysis coupled with genome scan using a large set of genetically mapped SNP markers and targeted genetic mapping by half tetrad analysis, using SSR and SNP markers, allowed locating a 3.3 Mb genomic region linked to ABS resistance near the centromere of chromosome III. Clusters of resistance genes were identified by gene ontology analysis of this genomic region. Some of these genes are good candidates to control the dominant susceptibility to the ACT-toxin. SSR and SNP markers were developed for efficient early marker-assisted selection of ABS resistant hybrids. PMID:24116149

  7. Stem Cells, Colorectal Cancer and Cancer Stem Cell Markers Correlations

    PubMed Central

    CHERCIU, IRINA; B?RB?LAN, A.; PIRICI, D.; M?RG?RITESCU, C.; S?FTOIU, A.

    2014-01-01

    : The idea of stem cells as being progenitors of cancer was initially controversial, but later supported by research in the field of leukemia and solid tumors. Afterwards, it was established that genetic abnormalities can affect the stem and progenitor cells, leading to uncontrolled replication and deregulated differentiation. These alterations will cause the changeover to cancerous stem cells (CSC) having two main characteristics: tumor initiation and maintenance. This review will focus on the colorectal cancer stem cell (CR-CSCs) theory which provides a better understanding of different tumor processes: initiation, aggressive growth, recurrence, treatment resistance and metastasis. A search in PubMed/Medline was performed using the following keywords: colorectal cancer stem cells (CR-CSCs), colorectal neoplasms stem cells, colorectal cancer stem cell (CR-CSCs) markers, etc. Electronic searches were supplemented by hand searching reference lists, abstracts and proceedings from meetings. Isolation of CR-CSCs can be achieved by targeting and selecting subpopulation of tumor cells based on expression of one or multiple cell surface markers associated with cancer self-renewal, markers as: CD133, CD166, CD44, CD24, beta1 integrin-CD29, Lgr5, EpCAM (ESA), ALDH-1, Msi-1, DCAMLK1 or EphB receptors. The identification and localization of CR-CSCs through different markers will hopefully lead to a better stratification of prognosis and treatment response, as well as the development of new effective strategies for cancer management. PMID:25729599

  8. Stem cells, colorectal cancer and cancer stem cell markers correlations.

    PubMed

    Cherciu, Irina; B?rb?lan, A; Pirici, D; M?rg?ritescu, C; S?ftoiu, A

    2014-01-01

    : The idea of stem cells as being progenitors of cancer was initially controversial, but later supported by research in the field of leukemia and solid tumors. Afterwards, it was established that genetic abnormalities can affect the stem and progenitor cells, leading to uncontrolled replication and deregulated differentiation. These alterations will cause the changeover to cancerous stem cells (CSC) having two main characteristics: tumor initiation and maintenance. This review will focus on the colorectal cancer stem cell (CR-CSCs) theory which provides a better understanding of different tumor processes: initiation, aggressive growth, recurrence, treatment resistance and metastasis. A search in PubMed/Medline was performed using the following keywords: colorectal cancer stem cells (CR-CSCs), colorectal neoplasms stem cells, colorectal cancer stem cell (CR-CSCs) markers, etc. Electronic searches were supplemented by hand searching reference lists, abstracts and proceedings from meetings. Isolation of CR-CSCs can be achieved by targeting and selecting subpopulation of tumor cells based on expression of one or multiple cell surface markers associated with cancer self-renewal, markers as: CD133, CD166, CD44, CD24, beta1 integrin-CD29, Lgr5, EpCAM (ESA), ALDH-1, Msi-1, DCAMLK1 or EphB receptors. The identification and localization of CR-CSCs through different markers will hopefully lead to a better stratification of prognosis and treatment response, as well as the development of new effective strategies for cancer management. PMID:25729599

  9. Leaving STEM: STEM Ph.D. Holders in Non-STEM Careers. Issue Brief

    ERIC Educational Resources Information Center

    Turk-Bicakci, Lori; Berger, Andrea

    2014-01-01

    During the last few decades, national, state, and institutional-level initiatives have been implemented to build and expand the science, technology, engineering, and mathematics (STEM) workforce by recruiting and retaining groups of individuals that have been traditionally underrepresented in STEM in higher education. The underlying theory of…

  10. Specialized and shared functions of the histidine kinase- and HOG1 MAP kinase-mediated signaling pathways in Alternaria alternata, a filamentous fungal pathogen of citrus.

    PubMed

    Lin, Ching-Hsuan; Chung, Kuang-Ren

    2010-10-01

    Signal transduction pathways are critical for the coordination of complex cellular processes in cells. In Alternaria alternata, a necrotrophic fungal pathogen of citrus, cloning and characterization of a gene coding a Group III histidine kinase (AaHSK1) and the yeast HOG1 ortholog (AaHOG1) showed the two genes to operate, both uniquely and synergistically, in a number of physiological and pathological functions. Systemic loss-of-function genetics in A. alternata revealed that AaHSK1 is a primary regulator for cellular resistance to sugar osmotic stress and for sensitivity to dicarboximide or phenylpyrrole fungicides. These functions were likely modulated by unknown mechanisms rather than solely by the AaHOG1-mediated pathway. AaHOG1, which conferred cellular resistance to salts and oxidative stress, also bypassed AaHSK1, even though deletion of AaHSK1 affected AaHOG1 phosphorylation. Phosphorylation of AaHOG1 was increased when the fungus was treated with osmotic stress, fungicides or H(2)O(2). Fungal mutants impaired in AaHSK1, AaHOG1, AaAP1 (encoding a redox-responsive transcription factor) or AaFUS3 (encoding a MAP kinase) were all hypersensitive to 2-chloro-5-hydroxypyridine (CHP) or 2,3,5-triiodobenzoic acid (TIBA). An AaHOG1::sGFP (synthetic green fluorescent protein) fusion protein became localized in the nucleus in response to H(2)O(2), CHP, TIBA, fungicides, but not glucose. Glucose, however, enhanced AaHOG1 phosphorylation and nuclear localization in the AaHSK1 deficient background. Accumulation of the AaHSK1 gene transcript was negatively regulated by AaHOG1, AaAP1 or AaFUS3. AaHOG1 was necessary for fungal pathogenicity, yet AaHSK1 was completely dispensable for pathogenicity. Our results highlight a dramatic flexibility and uniqueness in the signaling pathways that are involved in responding to diverse environmental stimuli in A. alternata. PMID:20601043

  11. Paving the road for lung stem cell biology: bronchioalveolar stem cells and other putative distal lung stem cells

    Microsoft Academic Search

    Carla F. Kim

    2007-01-01

    New discoveries in stem cell biology are making the biology of solid tissues increasingly complex. Important seminal studies demonstrating the presence of damage-resistant cell populations together with new isolation and characterization techniques suggest that stem cells exist in the adult lung. More detailed in vivo molecular and cellular characterization of bronchioalveolar stem cells (BASCs), other putative lung stem and progenitor

  12. [Multiple myeloma stem cell].

    PubMed

    Hosen, Naoki

    2015-01-01

    Multiple myeloma (MM) is characterized by the clonal expansion of malignant plasma cells. MM patients harbor phenotypic CD19+ B cells expressing the immunoglobulin gene sequence and the idiotype unique to the individual myeloma clone. However, in most MM patients CD19+ clonotypic B cells do not reconstitute MM disease upon transplantation into immune-deficient mice. In the SCID-rab and SCID-hu models, which enable engraftment of human MM in vivo, CD19-CD38++ plasma cells engrafted and rapidly propagated MM. These results indicate that MM-initiating cells are derived from plasma cells, which are terminally differentiated cells. It should be now clarified whether all MM plasma cells can exert as MM-initiating cells when located in the appropriate niche or only distinct myeloma stem cells can propagate MM. PMID:25626303

  13. Breast cancer stem cells

    PubMed Central

    Owens, Thomas W.; Naylor, Matthew J.

    2013-01-01

    Cancer metastasis, resistance to therapies and disease recurrence are significant hurdles to successful treatment of breast cancer. Identifying mechanisms by which cancer spreads, survives treatment regimes and regenerates more aggressive tumors are critical to improving patient survival. Substantial evidence gathered over the last 10 years suggests that breast cancer progression and recurrence is supported by cancer stem cells (CSCs). Understanding how CSCs form and how they contribute to the pathology of breast cancer will greatly aid the pursuit of novel therapies targeted at eliminating these cells. This review will summarize what is currently known about the origins of breast CSCs, their role in disease progression and ways in which they may be targeted therapeutically. PMID:23986719

  14. Pancreatic cancer stem cells

    PubMed Central

    Zhu, Ya-Yun; Yuan, Zhou

    2015-01-01

    Studies are emerging in support of the cancer stem cells (CSCs) theory which considers that a tiny subset of cancer cells is exclusively responsible for the initiation and malignant behavior of a cancer. This cell population, also termed CSCs, possesses the capacity both to self-renew, producing progeny that have the identical tumorigenic potential, and to differentiate into the bulk of cancer cells, helping serve the formation of the tumor entities, which, altogether, build the hierarchically organized structure of a cancer. In this review, we try to articulate the complicated signaling pathways regulating the retention of the characteristics of pancreatic CSCs, and in the wake of which, we seek to offer insights into the CSCs-relevant targeted therapeutics which are, in the meantime, confronted with bigger challenges than ever.

  15. Adult Stem and Progenitor Cells

    NASA Astrophysics Data System (ADS)

    Geraerts, Martine; Verfaillie, Catherine M.

    The discovery of adult stem cells in most adult tissues is the basis of a number of clinical studies that are carried out, with therapeutic use of hematopoietic stem cells as a prime example. Intense scientific debate is still ongoing as to whether adult stem cells may have a greater plasticity than previously thought. Although cells with some features of embryonic stem cells that, among others, express Oct4, Nanog and SSEA1 are isolated from fresh tissue, it is not clear if the greater differentiation potential is acquired during cell culture. Moreover, adult more pluripotent cells do not have all pluripotent characteristics typical for embryonic stem cells. Recently, some elegant studies were published in which adult cells could be completely reprogrammed to embryonic stem cell-like cells by overexpression of some key transcription factors for pluripotency (Oct4, Sox2, Klf4 and c-Myc). It will be interesting for the future to investigate the exact mechanisms underlying this reprogramming and whether similar transcription factor pathways are present and/or can be activated in adult more pluripotent stem cells.

  16. The new stem cell biology.

    PubMed Central

    Quesenberry, Peter J.; Colvin, Gerald A.; Lambert, Jean-Francois; Frimberger, Angela E.; Dooner, Mark S.; Mcauliffe, Christina I.; Miller, Caroline; Becker, Pamela; Badiavas, Evangelis; Falanga, Vincent J.; Elfenbein, Gerald; Lum, Lawrence G.

    2002-01-01

    Recent studies have indicated that bone marrow stem cells are capable of generating muscle, cardiac, hepatic, renal, and bone cells. Purified hematopoietic stem cells have generated cardiac and hepatic cells and reversed disease manifestations in these tissues. Hematopoietic stem cells also alter phenotype with cell cycle transit or circadian phase. During a cytokine stimulated cell cycle transit, reversible alterations of differentiation and engraftment occur. Primitive hematopoietic stem cells express a wide variety of adhesion and cytokine receptors and respond quickly with migration and podia extensions on exposure to cytokines. These data suggest an "Open Chromatin" model of stem cell regulation in which there is a fluctuating continuum in the stem cell/progenitor cell compartments, rather than a hierarchical relationship. These observations, along with progress in using low dose treatments and tolerization approaches, suggest many new therapeutic strategies involving stem cells and the creation of a new medical specialty; stemology. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:12053709

  17. Microarrayed Materials for Stem Cells

    PubMed Central

    Mei, Ying

    2013-01-01

    Stem cells hold remarkable promise for applications in disease modeling, cancer therapy and regenerative medicine. Despite the significant progress made during the last decade, designing materials to control stem cell fate remains challenging. As an alternative, materials microarray technology has received great attention because it allows for high throughput materials synthesis and screening at a reasonable cost. Here, we discuss recent developments in materials microarray technology and their applications in stem cell engineering. Future opportunities in the field will also be reviewed. PMID:24311967

  18. Endometrial stem/progenitor cells.

    PubMed

    Maruyama, Tetsuo

    2014-09-01

    Human endometrium regenerates and regresses with each menstrual cycle under hormonal control throughout a woman's reproductive life. The cyclical regeneration and remodeling potentials allude to the existence of stem/progenitor cells in the endometrium. There is increasing evidence that human endometrium contains small numbers of stem-like cells capable of self-renewal, multiple differentiation and tissue reconstitution. Although the precise identity of endometrial stem/progenitor cells remains elusive, these cells are thought to play pivotal role(s) in the physiological remodeling and regeneration of the human endometrium and also in the pathogenesis of endometrium-associated diseases, such as endometriosis. PMID:25160689

  19. Ferreting out stem cells from their niches

    Microsoft Academic Search

    Valerie Horsley; Elaine Fuchs

    2011-01-01

    Over the past decade, it has become increasingly clear that many tissues have regenerative capabilities. The challenge has been to find the stem cells or progenitors that are responsible for tissue renewal and repair. The revolution in technological advances that permit sophisticated spatial, temporal and kinetic analyses of stem cells has allowed stem cell hunters to ferret out where stem

  20. The STEM Initiative: Constraints and Challenges

    ERIC Educational Resources Information Center

    Herschbach, Dennis R.

    2011-01-01

    There is considerable national interest in STEM initiatives, but yet there is little discussion concerning what STEM means in terms of a curriculum concept to be applied to school programming. This article focuses on STEM as a curriculum concept. First, STEM programming is discussed in terms of separate subjects, correlated and broad fields…

  1. Cell Stem Cell Alternative Induced Pluripotent

    E-print Network

    Zandstra, Peter W.

    Cell Stem Cell Letter Alternative Induced Pluripotent Stem Cell Characterization Criteria, Canada 4Black Family Stem Cell Institute, Mount Sinai School of Medicine, New York, NY 10029, USA 5Samuel, Canada *Correspondence: jellis@sickkids.ca (J.E.), william.stanford@utoronto.ca (W.L.S.) DOI 10.1016/j.stem

  2. The Current Status of STEM Education Research

    ERIC Educational Resources Information Center

    Brown, Josh

    2012-01-01

    This paper explores the current Science, Technology, Engineering and Mathematics (STEM) education research base through an analysis of articles from eight journals focused on the STEM disciplines. Analyzed are both practitioner and research publications to determine the current scope of STEM education research, where current STEM education…

  3. Cell Stem Cell The Systematic Production

    E-print Network

    Zandstra, Peter W.

    Cell Stem Cell Review The Systematic Production of Cells for Cell Therapies Daniel C. Kirouac1 10.1016/j.stem.2008.09.001 Stem cells have emerged as the starting material of choice. Translating the biological properties and potential of stem cells into therapies will require overcoming

  4. The multifaceted adult epidermal stem cell

    Microsoft Academic Search

    Laure Gambardella; Yann Barrandon

    2003-01-01

    Adult epidermal stem cells renew the epithelial compartment of the skin throughout life and are the most accessible of all adult stem cells. Most importantly, epidermal stem cells can be efficiently cultivated and transplanted, a significant advantage for cell and gene therapy. Recent work has pointed to the hair follicle as the main repository of multipotent stem cells in skin.

  5. Matrix Elasticity Directs Stem Cell Lineage Specification

    E-print Network

    Discher, Dennis

    and also for therapeu- tic uses of stem cells. INTRODUCTION Adult stem cells, as part of normalMatrix Elasticity Directs Stem Cell Lineage Specification Adam J. Engler,1,2 Shamik Sen,1,2 H. Lee.06.044 SUMMARY Microenvironments appear important in stem cell lineage specification but can be difficult

  6. 28. Embryonic and adult stem cell therapy

    Microsoft Academic Search

    Carl T. Henningson; Marisha A. Stanislaus; Alan M. Gewirtz

    2003-01-01

    Stem cells are characterized by the ability to remain undifferentiated and to self-renew. Embryonic stem cells derived from blastocysts are pluripotent (able to differentiate into many cell types). Adult stem cells, which were traditionally thought to be monopotent multipotent, or tissue restricted, have recently also been shown to have pluripotent properties. Adult bone marrow stem cells have been shown to

  7. Stem Cell Migration in Health and Disease

    Microsoft Academic Search

    Thomas Dittmar; Susannah H. Kassmer; Benjamin Kasenda; Jeanette Seidel; Bernd Niggemann; Kurt S. Zänker

    2010-01-01

    Within the past years, our knowledge about stem cells in health and disease has changed dramatically. To date, it is feasible to isolate and propagate human pluripotent stem cells from various sources, such as cord blood, bone marrow or adipose tissue, and to generate donor-specific ethically harmless induced pluripotent stem cells, which exhibits embryonic stem cell properties. However, irrespective of

  8. Stem Cell Research: Elephants in the Room

    Microsoft Academic Search

    NEIL D. THEISE

    2003-01-01

    hen groups of stem cell researchers meet or when stem cell researchers publish their data and interpre- tations in scientific journals, a small cluster of important issues loom over the discussions yet often go unremarked. These issues influence much of the nature, direction, and funding of stem cell investigations, particularly those in- volving adult stem cells. The unmentionable issues are

  9. Columbia Stem Cell Initiative Tapping the potential of stem cells for human health

    E-print Network

    Adams, Mark

    Columbia Stem Cell Initiative Tapping the potential of stem cells for human health Tenure Track Faculty Positions in Stem Cell Research at Columbia University Medical Center The Columbia Stem Cell Initiative (CSCI; www.ColumbiaStemCell.org) brings together more than 120 groups working to tap the potential

  10. EMBRYONIC STEM CELLS or INDUCED PLURIPOTENT STEM CELLS? A DNA INTEGRITY PERSPECTIVE

    E-print Network

    Boyer, Edmond

    1 EMBRYONIC STEM CELLS or INDUCED PLURIPOTENT STEM CELLS? A DNA INTEGRITY PERSPECTIVE Qiang Bai Gene Therapy 2013;13(2):93-8" #12;2 ABSTRACT Induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) are two types of pluripotent stem cells that hold great promise for biomedical research

  11. Curr Gene Ther . Author manuscript Embryonic stem cells or induced pluripotent stem cells? A DNA integrity

    E-print Network

    Paris-Sud XI, Université de

    Curr Gene Ther . Author manuscript Page /1 7 Embryonic stem cells or induced pluripotent stem cells should be addressed to: John De Vos Abstract Induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) are two types of pluripotent stem cells that hold great promise for biomedical

  12. Cell Stem Cell Patient-Specific Pluripotent Stem Cells

    E-print Network

    Collins, James J.

    Yamanaka1,2,* 1Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507, Japan: yamanaka@cira.kyoto-u.ac.jp DOI 10.1016/j.stem.2010.06.009 In this issue of Cell Stem Cell, Staerk et al and ethical issues regarding the usage of human embryos (Yamanaka, 2009). Patient-specific iPSCs, especially

  13. Generation of induced pluripotent stem cells from neural stem cells

    Microsoft Academic Search

    Jeong Beom Kim; Holm Zaehres; Marcos J Araúzo-Bravo; Hans R Schöler

    2009-01-01

    The generation of induced pluripotent stem (iPS) cells from mouse and human somatic cells by expression of defined transcription factors (Oct4, Sox2, c-Myc, Klf4, Nanog and Lin28) is a powerful tool for conducting basic research and investigating the potential of these cells for replacement therapies. In our laboratory, iPS cells have been generated from adult mouse neural stem cells (NSCs)

  14. Hematopoietic Stem Cell Aging: Wrinkles In Stem Cell Potential

    Microsoft Academic Search

    S. M. Chambers; M. A. Goodell

    2007-01-01

    Hematopoietic stem cells (HSC) continuously replenish the blood and immune systems. Their activity must be sustained throughout\\u000a life to support optimal immune responses. It has been thought that stem cells may be somewhat protected from age because of\\u000a their perpetual requirement to replenish the blood, however studies over the past 10 years have revealed dramatic changes\\u000a in HSC function and phenotype

  15. Cancer stem cell subsets and their relationships

    PubMed Central

    2011-01-01

    Emerging evidence suggests that cancer stem cells account for the initiation and progression of cancer. While many types of cancer stem cells with specific markers have been isolated and identified, a variety of differences among them began to be appreciated. Cancer stem cells are hierarchical populations that consist of precancerous stem cells, primary cancer stem cells, migrating cancer stem cells and chemoradioresistant cancer stem cells, playing different roles in cancer initiation and progression. Here we propose a new concept "horizontal hierarchy of cancer stem cells" to distinguish them from vertical hierarchy cancer stem cells, cancer transient-amplifying cells and cancer differentiated cells, and summarize our current understanding of these subsets of cancer stem cells with the aim to open up novel therapeutic strategies for cancer based on this understanding. PMID:21542915

  16. Future Research in Adipose Stem Cell Engineering

    Microsoft Academic Search

    Jeanne Adiwinata Pawitan

    \\u000a Adipose stem cells have a bright prospect in regenerative medicine for tissue\\/organ engineering. However, some hurdles may\\u000a hinder the progress of adipose stem cell engineering. Therefore this chapter highlights the advances in adipose stem cell\\u000a researches, and focuses on prospective researches that are needed to overcome the hurdles in adipose stem cell engineering,\\u000a i.e., to identify the various stem cells

  17. Renal Stem Cells and Kidney Regeneration

    Microsoft Academic Search

    Takashi Yokoo; Akira Fukui; Kei Matsumoto; Tetsuya Kawamura

    \\u000a Significant advances have been made in stem cell research over the past decade. A number of non-hematopoietic sources of stem\\u000a cells (or progenitor cells) have been identified including endothelial stem cells and neural stem cells. These discoveries\\u000a have been a major step towards the potential regeneration of organs for clinical applications using stem cells. The worldwide\\u000a shortage of donor kidneys

  18. World stem cell summit 2014.

    PubMed

    Hasegawa, Kouichi; Asada, Takashi; Sengoku, Shintaro; Nakatsuji, Norio

    2015-05-01

    World Stem Cell Summit 2014 3-5 December 2014, San Antonio, TX, USA Among the many international conferences in the field of stem cells and regenerative medicine, WSCS is distinct in focusing its efforts to serve as the meeting point by multisector communities of research, clinics, industry, regulation, policy making and ethics. All are aiming at advancing stem cell innovation and new therapies, under the banner of 'connect, collaborate and cure'. As same as past years, presenters and attendees included not only researchers but also clinicians, funding agencies, government officials, industries and patients. Thus, many sessions focused on the clinical translation from basic research. Another important agenda were industrial and social aspects, and problems to be solved before realization of practical and sustainable stem cell-based therapies. PMID:26022760

  19. Controlled differentiation of stem cells?

    PubMed Central

    Hwang, Nathaniel S.; Varghese, Shyni; Elisseeff, Jennifer

    2009-01-01

    The extracellular microenvironment plays a significant role in controlling cellular behavior. Identification of appropriate biomaterials that support cellular attachment, proliferation and, most importantly in the case of human embryonic stem cells, lineage-specific differentiation is critical for tissue engineering and cellular therapy. In addition to growth factors and morphogenetic factors known to induce lineage commitment of stem cells, a number of scaffolding materials, including synthetic and naturally-derived biomaterials, have been utilized in tissue engineering approaches to direct differentiation. This review focuses on recent emerging findings and well-characterized differentiation models of human embryonic stem cells. Additionally, we also discuss about various strategies that have been used in stem cell expansion. PMID:18006108

  20. Stem cell mechanics: Auxetic nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Ning

    2014-06-01

    The nuclei of naive mouse embryonic stem cells that are transitioning towards differentiation expand when the cells are stretched and contract when they are compressed. What drives this auxetic phenotype is, however, unclear.

  1. Humboldt River main stem, Nevada

    USGS Publications Warehouse

    Warmath, Eric; Medina, Rose L.

    2001-01-01

    This data set contains the main stem of the Humboldt River as defined by Humboldt Project personnel of the U.S. Geological Survey Nevada District, 2001. The data set was digitized on screen using digital orthophoto quadrangles from 1994.

  2. Modeling Stem Cell Induction Processes

    E-print Network

    Grácio, Filipe

    Technology for converting human cells to pluripotent stem cell using induction processes has the potential to revolutionize regenerative medicine. However, the production of these so called iPS cells is still quite inefficient ...

  3. Differentiating Gametes from Stem Cells

    Microsoft Academic Search

    Ana Isabel Marqués-Marí; José Vicente Medrano; Carlos Simón

    \\u000a Embryonic stem cell lines derived from the inner cell mass of the blastocyst are pluripotent (they can differentiate into\\u000a all the different cell types) and have the ability to self-renewal in vitro, remaining undifferentiated. It has been demonstrated\\u000a that murine embryonic stem cells can give rise to structures very similar to sperm and oocytes in vitro. These differentiated cells are

  4. Metastasis and stem cell pathways

    Microsoft Academic Search

    Bryan C. Barnhart; M. Celeste Simon

    2007-01-01

    Recent studies have described a small population of self-renewing and multipotent cells within tumors termed “cancer stem\\u000a cells.” These cells share many traits with somatic and embryonic stem cells and are thought to be responsible for driving\\u000a tumor progression in a growing list of neoplastic diseases. Cells within solid tumors encounter hypoxia due to poor vascular\\u000a function. Both long-standing and

  5. Cancer Stem Cells and Microenvironment

    Microsoft Academic Search

    Mario Federico; Antonio Giordano

    \\u000a The theory of the cancer stem cell (CSC) is fairly recent and has both challenged and disrupted the previous understandings\\u000a of cancer biology. From the initial findings of cancer-driving cellular sub-populations, the interest in the CSC theory has\\u000a flourished. Here we discuss the biology behind both embryonic and adult stem cells and how this biology is the basis for our

  6. The stem cell debate CNN

    NSDL National Science Digital Library

    2001-01-01

    As most of our readers no doubt know, President Bush made a determination on federal funding for embryonic stem cell research in August 2001, agreeing to release federal funds for research involving already existing stem cell lines. Information on this contentious topic is available at CNN's in-depth special, which features articles, analysis, video clips, and message boards devoted to the many aspects of the debate.

  7. Stem Cells Promises to Keep?

    NSDL National Science Digital Library

    Lauren E. Yaich

    2002-01-01

    Samantha and her husband Brad have two children, conceived with the help of in vitro fertilization treatments. After viewing a TV program on stem cells and their potential medical uses, Samantha is convinced that they should donate the remaining frozen embryos they have to medical research, an idea Brad strongly objects to. The case teaches about stem cells and their medical applications as well as the ethical dilemmas posed by their use.

  8. Stem cells from adipose tissue

    Microsoft Academic Search

    Malgorzata Witkowska-Zimny; Katarzyna Walenko

    2011-01-01

    This is a review of the growing scientific interest in the developmental plasticity and therapeutic potential of stromal cells\\u000a isolated from adipose tissue. Adipose-derived stem\\/stromal cells (ASCs) are multipotent somatic stem cells that are abundant\\u000a in fat tissue. It has been shown that ASCs can differentiate into several lineages, including adipose cells, chondrocytes,\\u000a osteoblasts, neuronal cells, endothelial cells, and cardiomyocytes.

  9. Perspectives on metaphyseal conservative stems

    Microsoft Academic Search

    F. Falez; F. Casella; G. Panegrossi; F. Favetti; C. Barresi

    2008-01-01

    Total hip replacement is showing, during the last decades, a progressive evolution toward principles of reduced bone and soft\\u000a tissue aggression. These principles have become the basis of a new philosophy, tissue sparing surgery. Regarding hip implants,\\u000a new conservative components have been proposed and developed as an alternative to conventional stems. Technical and biomechanical\\u000a characteristics of metaphyseal bone-stock-preserving stems are

  10. Structural analysis of wheat stems

    Microsoft Academic Search

    Kurt D. Hamman; Richard L. Williamson; Eric D. Steffler; Christopher T. Wright; J. Richard Hess; Peter A. Pryfogle

    2005-01-01

    Design and development of improved harvesting, preprocessing, and bulk handling systems for biomass requires knowledge of\\u000a the biomechanical properties and structural characteristics of crop residue. Structural analysis of wheat stem cross-sections\\u000a was performed using the theory of composites and finite element analysis techniques. Representative geometries of the stem’s\\u000a structural components including the hypoderm, ground tissue, and vascular bundles were established

  11. Structural Analysis of Wheat Stems

    Microsoft Academic Search

    Kurt D. Hamman; Richard L. Williamson; Eric D. Steffler; Christopher T. Wright; J. Richard Hess; Peter A. Pryfogle

    Design and development of improved harvesting, preprocessing, and bulk handling systems for biomass requires knowledge of\\u000a the biomechanical properties and structural characteristics of crop residue. Structural analysis of wheat stem cross-sections\\u000a was performed using the theory of composites and finite element analysis techniques. Representative geometries of the stem’s\\u000a structural components including the hypoderm, ground tissue, and vascular bundles were established

  12. Stem Cells in the Lung

    PubMed Central

    Liu, Xiaoming; Driskell, Ryan R.; Engelhardt, John F.

    2007-01-01

    The lung is composed of two major anatomically distinct regions—the conducting airways and gas-exchanging airspaces. From a cell biology standpoint, the conducting airways can be further divided into two major compartments, the tracheobronchial and bronchiolar airways, while the alveolar regions of the lung make up the gas-exchanging airspaces. Each of these regions consists of distinct epithelial cell types with unique cellular physiologies and stem cell compartments. This chapter focuses on model systems with which to study stem cells in the adult tracheobronchial airways, also referred to as the proximal airway of the lung. Important in such models is an appreciation for the diversity of stem cell niches in the conducting airways that provide localized environmental signals to both maintain and mobilize stem cells in the setting of airway injury and normal cellular turnover. Because cellular turnover in airways is relatively slow, methods for analysis of stem cells in vivo have required prior injury to the lung. In contrast, ex vivo and in vitro models for analysis of airway stem cells have used genetic markers to track lineage relationships together with reconstitution systems that mimic airway biology. Over the past decades, several widely acceptable methods have been developed and used in the characterization of adult airway stem/ progenitor cells. These include localization of label-retaining cells (LRCs), retroviral tagging of epithelial cells seeded into xenografts, air–liquid interface cultures to track clonal proliferative potential, and multiple transgenic mouse models. This chapter reviews the biologic context and use of these models while providing detailed methods for several of the more broadly useful models for studying adult airway stem/progenitor cell types. PMID:17141060

  13. Progress in myeloma stem cells

    PubMed Central

    Cruz, Richard Dela; Tricot, Guido; Zangari, Maurizio; Zhan, Fenghuang

    2011-01-01

    Multiple myeloma (MM) is the second most common hematologic malignancy in the United States and affects about 4 in 100,000 Americans. Even though much progress has been made in MM therapy, MM remains an incurable disease for the vast majority of patients. The existence of MM stem cell is considered one of the major causes of MM drug-resistance, leading to relapse. This highlights the importance and urgency of developing approaches to target MM stem cells. However, very little is known about the molecular characteristics of the MM stem cells, which makes it difficult to target MM stem cells therapeutically. Evidence of the existence of a myeloma stem cell has been provided by Matsui et al. showing that the CD138- and CD20+ fraction, which is a minor population of the MM cells, has a greater clonogenic potential and has the phenotype of a memory B-cell (CD19+, CD27+). In this review, we report recent progress of cell surface markers in cancer stem cells, especially in myeloma and the molecular mechanisms related to drug resistance and myeloma disease progression. PMID:22432075

  14. Progress in myeloma stem cells.

    PubMed

    Cruz, Richard Dela; Tricot, Guido; Zangari, Maurizio; Zhan, Fenghuang

    2011-01-01

    Multiple myeloma (MM) is the second most common hematologic malignancy in the United States and affects about 4 in 100,000 Americans. Even though much progress has been made in MM therapy, MM remains an incurable disease for the vast majority of patients. The existence of MM stem cell is considered one of the major causes of MM drug-resistance, leading to relapse. This highlights the importance and urgency of developing approaches to target MM stem cells. However, very little is known about the molecular characteristics of the MM stem cells, which makes it difficult to target MM stem cells therapeutically. Evidence of the existence of a myeloma stem cell has been provided by Matsui et al. showing that the CD138- and CD20+ fraction, which is a minor population of the MM cells, has a greater clonogenic potential and has the phenotype of a memory B-cell (CD19+, CD27+). In this review, we report recent progress of cell surface markers in cancer stem cells, especially in myeloma and the molecular mechanisms related to drug resistance and myeloma disease progression. PMID:22432075

  15. Diabetes and Stem Cell Function

    PubMed Central

    Fujimaki, Shin; Wakabayashi, Tamami; Takemasa, Tohru; Asashima, Makoto; Kuwabara, Tomoko

    2015-01-01

    Diabetes mellitus is one of the most common serious metabolic diseases that results in hyperglycemia due to defects of insulin secretion or insulin action or both. The present review focuses on the alterations to the diabetic neuronal tissues and skeletal muscle, including stem cells in both tissues, and the preventive effects of physical activity on diabetes. Diabetes is associated with various nervous disorders, such as cognitive deficits, depression, and Alzheimer's disease, and that may be caused by neural stem cell dysfunction. Additionally, diabetes induces skeletal muscle atrophy, the impairment of energy metabolism, and muscle weakness. Similar to neural stem cells, the proliferation and differentiation are attenuated in skeletal muscle stem cells, termed satellite cells. However, physical activity is very useful for preventing the diabetic alteration to the neuronal tissues and skeletal muscle. Physical activity improves neurogenic capacity of neural stem cells and the proliferative and differentiative abilities of satellite cells. The present review proposes physical activity as a useful measure for the patients in diabetes to improve the physiological functions and to maintain their quality of life. It further discusses the use of stem cell-based approaches in the context of diabetes treatment.

  16. In Appreciation of Stem Cell Research Doners..............................................................1 Glossary ..........................................................................................................................4

    E-print Network

    Shapiro, Ehud

    #12;#12;In Appreciation of Stem Cell Research Doners ..........................................................................................................................4 Stem Cell Research at the Weizmann Institute of Science......................................................9 Germ-Line Stem Cell Differentiation

  17. Stem Cells: It's Good To Have Choices

    PubMed Central

    Bellayr, Ian H.; Li, Yong

    2009-01-01

    Three types of stem cells, embryonic, adult, and induced pluripotent stem cells, are currently studied by scientists. Barack Obama's presidency has opened the door for stem cell research by revoking statements and orders made during the former President Bush's administration. This provisional period will allow the National Institute of Health to rewrite policies governing how federal funds are distributed for stem cell research. These new regulations will grant more freedom to researchers wishing to use stem cells in their research and challenge them to determine the most appropriate stem cell treatment for a given disorder. PMID:20161527

  18. Stemming heart failure with cardiac- or reprogrammed-stem cells.

    PubMed

    Tateishi, Kento; Takehara, Naofumi; Matsubara, Hiroaki; Oh, Hidemasa

    2008-12-01

    Despite extensive efforts to control myocyte growth by genetic targeting of the cell cycle machinery and small molecules for cardiac repair, adult myocytes themselves appeared to divide a limited number of times in response to a variety of cardiac muscle stresses. Rare tissue-resident stem cells are thought to exist in many adult organs that are capable of self-renewal and differentiation and possess a range of actions that are potentially therapeutic. Recent studies suggest that a population of cardiac stem cells (CSCs) is maintained after cardiac development in the adult heart in mammals including human beings; however, homeostatic cardiomyocyte replacement might be stem cell-dependent, and functional myocardial regeneration after cardiac muscle damage is not yet considered as sufficient to fully maintain or reconstitute the cardiovascular system and function. Although it is clear that adult CSCs have limitations in their capabilities to proliferate extensively and differentiate in response to injury in vivo for replenishing mature car-diomyocytes and potentially function as resident stem cells. Transplantation of CSCs expanded ex vivo seems to require an integrated strategy of cell growth-enhancing factor(s) and tissue engineering technologies to support the donor cell survival and subsequent proliferation and differentiation in the host microenvironment. There has been substantial interest regarding the evidence that mammalian fibroblasts can be genetically reprogrammed to induced pluripotent stem (iPS) cells, which closely resemble embryonic stem (ES) cell properties capable of differentiating into functional cardiomyocytes, and these cells may provide an alternative cell source for generating patient-specific CSCs for therapeutic applications. PMID:18754813

  19. Multilocus Variable-Number-Tandem-Repeats Analysis (MLVA) distinguishes a clonal complex of Clavibacter michiganensis subsp. michiganensis strains isolated from recent outbreaks of bacterial wilt and canker in Belgium

    PubMed Central

    2013-01-01

    Background Clavibacter michiganensis subsp. michiganensis (Cmm) causes bacterial wilt and canker in tomato. Cmm is present nearly in all European countries. During the last three years several local outbreaks were detected in Belgium. The lack of a convenient high-resolution strain-typing method has hampered the study of the routes of transmission of Cmm and epidemiology in tomato cultivation. In this study the genetic relatedness among a worldwide collection of Cmm strains and their relatives was approached by gyrB and dnaA gene sequencing. Further, we developed and applied a multilocus variable number of tandem repeats analysis (MLVA) scheme to discriminate among Cmm strains. Results A phylogenetic analysis of gyrB and dnaA gene sequences of 56 Cmm strains demonstrated that Belgian Cmm strains from recent outbreaks of 2010–2012 form a genetically uniform group within the Cmm clade, and Cmm is phylogenetically distinct from other Clavibacter subspecies and from non-pathogenic Clavibacter-like strains. MLVA conducted with eight minisatellite loci detected 25 haplotypes within Cmm. All strains from Belgian outbreaks, isolated between 2010 and 2012, together with two French strains from 2010 seem to form one monomorphic group. Regardless of the isolation year, location or tomato cultivar, Belgian strains from recent outbreaks belonged to the same haplotype. On the contrary, strains from diverse geographical locations or isolated over longer periods of time formed mostly singletons. Conclusions We hypothesise that the introduction might have originated from one lot of seeds or contaminated tomato seedlings that was the source of the outbreak in 2010 and that these Cmm strains persisted and induced infection in 2011 and 2012. Our results demonstrate that MLVA is a promising typing technique for a local surveillance and outbreaks investigation in epidemiological studies of Cmm. PMID:23738754

  20. Problematizing the STEM Pipeline Metaphor: Is the STEM Pipeline Metaphor Serving Our Students and the STEM Workforce?

    ERIC Educational Resources Information Center

    Cannady, Matthew A.; Greenwald, Eric; Harris, Kimberly N.

    2014-01-01

    Researchers and policy makers often use the metaphor of an ever-narrowing pipeline to describe the trajectory to a science, technology, engineering or mathematics (STEM) degree or career. This study interrogates the appropriateness of the STEM pipeline as the dominant frame for understanding and making policies related to STEM career trajectories.…