bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Verticillium Wilt Caused by Verticillium dahliae on Lettuce in Italy
Authors: Garibaldi A. , Gilardi G. , Gullino M. L. 
Published: May 2007

Lettuce (Lactuca sativa L.) is an important crop used for fresh and processing markets in Italy and is grown on more than 21,000 ha. During October and November of 2006, wilt symptoms were observed on field-grown lettuce, cv. Estelle, in Forlì, Emila Romagna (northeastern Italy) and on cv. Ballerina grown under plastichouses in Piedmont (northwestern Italy). Both lettuce cultivars were of a butterhead type. Affected plants were stunted and developed yellow leaves with brown or black streaks in the vascular tissue. Yellowing started from the external leaves. Discoloration was observed in the vascular tissue of roots, crown, and leaves. A fungus was consistently and readily isolated from symptomatic vascular tissue, previously disinfested in 1% sodium hypochlorite, when cultured on potato dextrose agar (PDA). Microscopic observations revealed hyaline hyphae with many ovoid, dark microsclerotia measuring 32 to 43 × 16 to 26 μm developing after 15 days of growth at 18°C in the dark. Conidiophores showed two verticils of three elements. Conidia were hyaline, elliptical, single celled, and measured 3.5 to 8.5 × 1.8 to 4.3 μm (average 5.5 × 2.5 μm). According to its morphological characteristics, the fungus was identified as Verticillium dahliae (2). Healthy, 20-day-old lettuce plants, cvs. Principessa and Maxima, both belonging to the butterhead type, were separately inoculated by root dip with a conidial suspension (106/ml) of two isolates of V. dahliae isolated, respectively, at Forlì and Torino. Noninoculated lettuce plants served as control treatments. Plants (10 per treatment) were grown in pots (10-liter vol.) in a steam-disinfested peat/perlite/sand (3:1:1 vol/vol) substrate and were maintained in a glasshouse at temperatures ranging between 17 and 22°C and relative humidity ranging between 60 and 70%. First wilt symptoms and vascular discoloration in the roots, crown, and veins developed 40 days after the artificial inoculation. Forty percent of the plants were affected in the case of cv. Maxima and 30% for cv. Principessa. Noninoculated plants remained healthy. The pathogenicity tests were repeated twice. To our knowledge, this is the first report in Italy of Verticillium wilt on lettuce. The disease has been previously reported in Greece (1) and the United States (3). Currently, Verticillium wilt of lettuce seems restricted in Italy to very few farms in the two locations; moreover, its incidence is very low (0.05%). References: (1) E. K. Ligoxigakis et al. Phytoparasitica 30:141, 2002. (2) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002. (3) G. E. Vallad et al. Plant Dis. 89:317, 2005.
First Report of Target Spot of Vaccinium corymbosum Caused by Corynespora cassiicola
Authors: Hongn S. , Ramallo A. , Baino O. , Ramallo J. C. 
Published: May 2007

During March of 2006, in Famailla, Province of Tucuman, Argentina, a new foliar disease was observed on Vaccinium corymbosum L. cv. O'Neal causing severe premature leaf drop. Symptoms consisted of circular to irregular reddish brown necrotic spots varying from specks to mature lesions of 10 to 15 mm in diameter. Larger spots frequently exhibited a zonate pattern with lighter centers and darker margins that are surrounded by a black, oily halo that is consistent with target spot (3). Lesions often coalesced to form irregularly shaped necrotic areas that reached the petioles. Leaf abscission occurred soon after >50% of the foliar area was affected. No stem lesions were observed. Conidiophores were erect, brown, single or in clusters, one to seven septa, 6 to 9 × 70 to 684 μm (shorter in culture), and arose on the abaxial surface of diseased leaves; conidia were borne singly or in chains of 2 to 5, varying from cylindrical to broadest at the base and tapering toward the apex, straight to slightly curved, 3 to 20 pseudosepta, 75 to 330 × 5 to 9 μm (mean of 153 × 7 μm, shorter in culture), with conspicuous hilum. On potato dextrose agar (PDA), the rate of growth was moderate (colonies reach 25 mm in diameter after 7 days grown at 27°C) with conidia production 5 days after the culture was started. Microscopic characters and cultural patterns conformed to the description of Corynespora cassiicola (Berk & M. A. Curtis) C.T. Wei (2,4) and were identical to isolates of C. cassicola from lesions of soybean target spot. A conidial suspension (104 conidia/ml) of C. cassicola was prepared from a 2-week-old culture grown on PDA and sprayed on surface-disinfected excised blueberry stems, each with 10 healthy leaves per stem. The stems were placed in hydroponia and incubated at 27 ± 2°C with permanent light. All sprayed leaves showed symptoms within 3 days following inoculation. Within 5 days, leaves were conspicuously infected, soon followed by defoliation. C. cassicola was reisolated from the inoculated-leaves lesions and was identical morphologically to the original isolate sprayed on test leaves. Another Corynespora species, C. arctespora (Cooke & Ellis) Carris (1), was described on Vaccinium spp. stems with a distinctive feature of a phialidic synanamorph formation. This synanamorph character was not found in our isolate. C. cassiicola has a broad hosts range, but to our knowledge, has not been recorded before on V. corymbosum as the causal agent of target spot. References: (1) L. M. Carris. Mycotaxon 30:127, 1987. (2) L. S. Olive et al. Phytopathology 35:822, 1945. (3) J. B. Sinclair. Target spot. Page 27 in: Compendium of Soybean Diseases. G. L Hartman et al., eds. The American Phytopathological Society. St. Paul, MN, 1999. (4) J. A. Spencer and H. J. Walters. Phytopathology 59:58, 1969.
First Report of Canker and Dieback Disease of Grevillea robusta in East Africa Caused by Botryosphaeria spp.
Authors: Toljander Y. K. , Nyeko P. , Stenström E. , Ihrmark K. , Barklund P. 
Published: May 2007

An outbreak of a canker and dieback disease was observed for the first time on Grevillea robusta in Uganda during October of 2001. Disease symptoms included dieback of shoots and branches, lesions and canker formation on the stems, clear or yellow-to-red exudates on stems and branches, formation of clusters of small and deformed leaves, and sapling and tree mortality. Isolations were made from the inner bark and wood of stems and branches in the Masaka and Rakai districts of Uganda in March and August to October of 2003. Samples from the border between healthy and necrotic tissues were plated on potato dextrose agar, vegetable juice agar, and water agar as well as on selective Phytophthora medium. Fungal isolates from several of the symptomatic trees were identified as belonging to the genus Botryosphaeria on the basis of morphological characteristics. Botryosphaeria-like fungi were not isolated from healthy trees. The internal transcribed spacer regions of the ribosomal DNA, as well as parts of the beta-tubulin and elongation factor 1-alpha genes, were sequenced from eight of these isolates. Five isolates matched Botryosphaeria parva in GenBank and one isolate matched B. rhodina. Two isolates matched an unidentified Botryosphaeria sp. previously isolated from Eucalyptus grandis in Uganda (GenBank Accession Nos. AY228102 and AY226852). Pathogenicity tests were performed by inoculating 10 18-month-old G. robusta seedlings with each isolate. A 10-mm3 malt agar plug with mycelium was inserted into a cut in the bark and the wound was sealed using grafting tape. One month after inoculation, the number of seedlings displaying death from the point of inoculation to the top (TM) and whole seedling mortality (SM) were recorded. Six of the isolates produced pathogenic responses in the seedlings: Botryosphaeria sp. isolate 1 (TM 10, SM 2), Botryosphaeria sp. isolate 2 (TM 10, SM 1), B. parva isolate 1 (TM 6, SM 1), B. parva isolate 2 (TM 3, SM 1), B. parva isolate 3 (TM 3, SM 0), and B. parva isolate 4 (TM1, SM 0). Inoculation with B. parva isolate 5 and B. rhodina, as well as sterile agar plugs, resulted in no TM or SM. The canker and dieback disease seems to be widespread in the East African Region since typical symptoms have been observed on G. robusta in Kenya (February 2004) and Ethiopia (February 2006). Botryosphaeria spp. are known to have multiple hosts and have been isolated from several other species in this region, including Eucalyptus spp. (1,2). From these findings, it appears that the same species of Botryosphaeria, which are previously known to be pathogenic on Eucalyptus, also cause serious disease on G. robusta. References: (1) A. Gezahgne et al. S. Afr. J. Sci. 99:29, 2003. (2) J. Roux et al. S. Afr. J. Sci. 97:16, 2001.
Fine Needle Aspiration Cytology of Myxoid Liposarcoma; A Study of 18 Tumours
Authors: SZADOWSKA A. , LASOTA J. 
Published: May 2007

The cytological features of 18 myxoid liposarcomas from 12 patients were analysed. the most consistent cytological features were: abundant myxoid matrix, several small tissue fragments with uniform small, round or stellate cells and a network of branching thin‐walled capillaries. the presence of univacuolated or multivacuolated lipoblasts was noted frequently, but not in all aspirates. the diagnostic importance of vacuolated lipoblasts and the main problems of differential cytodiagnosis are discussed.Une série de 18 cytoponctions provenant de 12 patients chez qui un diagnostic de liposarcome myxoïde a été porté cytologiquement et histologiquement est analysée. Les caractéristiques cytologiques les plus constantes sont la présence d'une matrice myxoïde abondante, de petits fragments tissulaires constitués de cellules rondes ou étoilées assez monomorphes et d'un réseau branché de capillaires à paroi fine. La présence de lipoblastes mono ou pluri‐vacuolisés est fréquente mais non constante. L'importance diagnostique de ces lipoblastes vacuolisés et les problèmes majeurs de cytodiagnostic différentiel sont discutés.Feinnadelpunktate wurden von 18 histologisch gesicherten myxoiden Liposarkomen von 12 Patienten hergestellt. Die zuverlässigsten zytologischen Kriterien waren: reichlich myxoide Grundsubstanz, kleinere Gewebsfragemente einheitlicher, runder oder sternförmiger Zellen und Bruchstücke dünnwandiger Kapillaren. Lipoblasten mit einer oder mehreren Vakuolen wurden häufig, jedoch nicht in allen Punktaten gefunden. Ihre diagnostische Bedeutung für die Differentialdiagnose wird diskutiert.
Reliability of Fine Needle Aspiration Cytology For Distinguishing Between Carcinoma, Lymphoma and Sarcoma; the Influence of Clinical Information
Authors: THUNNISSEN F. B. J. M. , PETERSE J. L. , VAN PEL R. , JANSEN J.‐W. , LADDÉ B. E. , ARENDS J.‐W. , VOLOVICS A. 
Published: May 2007

To investigate interobserver variation of fine needle aspiration (FNA) cytological diagnosis with respect to distinguishing between carcinoma, sarcoma and lymphoma, a set of 80 randomly sampled slides was randomized twice and read ‘blindly’by five cytopathologists. In the first round the slides were read without any information, and in the second round clinical information was provided. Histology was used as a reference standard. In the first round, the positive predictive values for the cytological diagnosis of carcinoma, sarcoma and lymphoma were 93%, 94% and 86% respectively. In the second round the positive predictive values for the cytological diagnoses of carcinoma, sarcoma and lymphoma were 95%, 99% and 99%, respectively. Interobserver variability, tested with weighted kappa scores (range 0.73–0.92) between histological and cytological diagnosis, was low. the most accurate FNA cytologic classification was obtained when the clinical context was known.L'étude de la variabilité interobservateur du diagnostic différentiel entre carcinome, sarcome et lymphome par cytoponction à l'aiguille fine a été conduite sur 80 cas pris au hasard. Deux lectures successives ont été faites ‘en aveugle’par 5 cytopathologistes. Les renseignements cliniques n'one été fournis que lors de la deuxième lecture. L'histopathologie est le standard de référence. Après la première lecture, la valeur prédictive positive moyenne du diagnostic de carcinome, de sarcome et de lymphome est respectivement de 93%, 94% et 86%. Après la seconde lecture, ces valeurs sont respectivement de 95%, 99% et 99%. La variabilité interobservateur, testée par le score kappa pondéré (intervalle de 0.73 à 0.92) entre les diagnostics histologiquest et cytologiques est faible. Le meilleur résultat est obtenu lorsque le contexte clinique est connu.Zur Überprüfung der Übereinstimmung zwischen verschiedenen Zytopathologen wurden 80 Präparate von Karzinomen, Sarkomen und Lymphomen zweimal randomisiert und von 5 Zytopathologen blind ausgewertet. In der 1. Runde erfolgte dies ohne Zusatzinformation, in der 2. mit klinischen Informationen. Bezugsstandard war die Histologie. In der 1. Runde waren die positiven praediktiven Werte für Karzinom, Sarkom und Lymphom 93%, 94% bzw. 86%. In der 2. Runde betrugen die Werte 95%, 99% und 99%. Testet man die Variabilität zwischen den Auswertern mit Kappawerten (0.73–0.92), so ergeben sich nur geringe Unterschiede in der Zuverlässigkeit zwischen histologischer und zytologischer Diagnose. Die besten zytologischen Ergebnisse werden erreicht, wenn die klinischen Daten bekannt sind.
Characterization of a TFIIH homologue fromTrypanosoma brucei
Authors: Lecordier Laurence , Devaux Sara , Uzureau Pierrick , Dierick Jean François , Walgraffe David , Poelvoorde Philippe , Pays Etienne , Vanhamme Luc 
Published: May 2007

SummaryTrypanosomes are protozoans showing unique transcription characteristics. We describe inTrypanosoma bruceia complex homologous to TFIIH, a multisubunit transcription factor involved in the control of transcription by RNA Pol I and RNA Pol II, but also in DNA repair and cell cycle control. Bioinformatics analyses allowed the detection of five genes encoding four putative core TFIIH subunits (TbXPD, TbXPB, Tbp44, Tbp52), including a novel XPB variant, TbXPBz. In all cases sequences known to be important for TFIIH functions were conserved. We performed a molecular analysis of this core complex, focusing on the two subunits endowed with a known enzymatic (helicase) activity, XPD and XPB. The involvement of theseT. bruceiproteins in abona fideTFIIH core complex was supported by (i) colocalization by immunofluorescence in the nucleus, (ii) direct physical interaction of TbXPD and its interacting regulatory subunit Tbp44 as determined by double‐hybrid assay and tandem affinity purification of the core TFIIH, (iii) involvement of the core proteins in a high molecular weight complex and (iv) occurrence of transcription, cell cycle and DNA repair phenotypes upon either RNAi knock‐down or overexpression of essential subunits.
The regulation of zinc homeostasis by the ZafA transcriptional activator is essential for Aspergillus fumigatus virulence
Authors: Moreno Miguel Ángel , Ibrahim‐Granet Oumaima , Vicentefranqueira Rocío , Amich Jorge , Ave Patrick , Leal Fernando , Latgé Jean‐Paul , Calera José Antonio 
Published: May 2007

SummaryWe have previously shown that Aspergillus fumigatus is able to grow in zinc‐limiting media and that this ability is regulated at transcriptional level by both the availability of zinc and pH. When A. fumigatus grows as a pathogen, it must necessarily obtain zinc from the zinc‐limiting environment provided by host tissue. Accordingly, the regulation of zinc homeostasis by some zinc‐responsive transcriptional regulator in A. fumigatus must be essential for fungal growth within tissues of an immunocompromised host and, in turn, for pathogenicity. Here we provide evidence of the role of the zafA gene in regulating zinc homeostasis and its relevance in the virulence of A. fumigatus. Thus, we observed that (i) zafA can functionally replace the ZAP1 gene from Saccharomyces cerevisiae that encodes the zinc‐responsive transcriptional activator Zap1 protein; (ii) the expression of zafA itself is induced in zinc‐limiting media and repressed by zinc; (iii) deletion of zafA impairs the germination and growth capacity of A. fumigatus in zinc‐limiting media; and (iv) the deletion of zafA abrogates A. fumigatus virulence in a murine model of invasive aspergillosis. In light of these observations, we concluded that ZafA is a zinc‐responsive transcriptional activator that represents an essential attribute for A. fumigatus pathogenicity. Consequently, ZafA may constitute a new target for the development of chemotherapeutic agents against Aspergillus, because no zafA orthologues have been found in mammals.
Identification and type III‐dependent secretion of the Yersinia pestis insecticidal‐like proteins
Authors: Gendlina Inessa , Held Kiara G. , Schesser Bartra Sara , Gallis Byron M. , Doneanu Catalin E. , Goodlett David R. , Plano Gregory V. , Collins Carleen M. 
Published: May 2007

SummaryPlague, or the Black Death, is a zoonotic disease that is spread from mammal to mammal by fleas. This mode of transmission demands that the causative agent of this disease, Yersinia pestis, is able to survive and multiply in both mammals and insects. In recent years the complete genome sequence of a number of Y. pestis strains have been determined. This sequence information indicates that Y. pestis contains a cluster of genes with homology to insecticidal toxin encoding genes of the insect pathogen Photorhabdus luminescens. Here we demonstrate that Y. pestis KIM strains produced the encoded proteins. Production of the locus‐encoded proteins was dependent on a gene (yitR) encoding a member of the LysR family of transcriptional activators. Evidence suggests the proteins are type III secretion substrates. N terminal amino acids (100 to 367) of each protein fused to an epitope tag were secreted by the virulence plasmid type III secretion type. A fusion protein comprised of the N‐terminus of YipB and the enzymatic active component of Bordetella pertussis adenylate cyclase (Cya) was translocated into both mammalian and insect cells. In conclusion, a new class of Y. pestis type III secreted and translocated proteins has been identified. We hypothesize that these proteins function to promote transmission of and infection by Y. pestis.
Loss of the controlled localization of growth stage‐specific cell‐wall synthesis pleiotropically affects developmental gene expression in an ssgA mutant of Streptomyces coelicolor
Authors: Noens Elke E. , Mersinias Vassilis , Willemse Joost , Traag Bjørn A. , Laing Emma , Chater Keith F. , Smith Colin P. , Koerten Henk K. , Van Wezel Gilles P. 
Published: May 2007

SummaryMembers of the family of SsgA‐like proteins (SALPs) are found exclusively in sporulating actinomycetes, and SsgA itself activates sporulation‐specific cell division. We previously showed that SALPs play a chaperonin‐like role in supporting the function of enzymes involved in peptidoglycan maintenance (PBPs and autolysins). Here we show that SsgA localizes dynamically during development, and most likely marks the sites where changes in local cell‐wall morphogenesis are required, in particular septum formation and germination. In sporogenic aerial hyphae, SsgA initially localizes as strong foci to the growing tips, followed by distribution as closely spaced foci in a pattern similar to an early stage of FtsZ assembly. Spore septa formed in these hyphae colocalize with single SsgA‐GFP foci, and when the maturing spores are separated, these foci are distributed symmetrically, resulting in two foci per mature spore. Evidence is provided that SsgA also controls the correct localization of germination sites. Transcriptome analysis revealed that expression of around 300 genes was significantly altered in mutants in ssgA and its regulatory gene ssgR. The list includes surprisingly many known developmental genes, most of which were upregulated, highlighting SsgA as a key player in the control of Streptomyces development.
The small RNA RyhB activates the translation of shiA mRNA encoding a permease of shikimate, a compound involved in siderophore synthesis
Authors: Prévost Karine , Salvail Hubert , Desnoyers Guillaume , Jacques Jean‐François , Phaneuf Émilie , Massé Eric 
Published: May 2007

SummaryRyhB is a small RNA (sRNA) that downregulates about 20 genes involved in iron metabolism. It is expressed under low iron conditions and pairs with specific mRNAs to trigger their rapid degradation by the RNA degradosome. In contrast to this, another study has suggested that RyhB also activates several genes by increasing their mRNA level. Among these activated genes is shiA, which encodes a permease of shikimate, an aromatic compound participating in the biosynthesis of siderophores. Here, we demonstrate in vivo and in vitro that RyhB directly pairs at the 5′‐untranslated region (5′‐UTR) of the shiA mRNA to disrupt an intrinsic inhibitory structure that sequesters the ribosome‐binding site (Shine‐Dalgarno) and the first translation codon. This is the first demonstration of direct gene activation by RyhB, which has been exclusively described in degradation of mRNAs. Our physiological results indicate that the transported compound of the ShiA permease, shikimate, is important under conditions of RyhB expression, that is, iron starvation. This is demonstrated by growth assays in which shikimate or the siderophore enterochelin correct the growth defect observed for a ryhB mutant in iron‐limited media.
Clostridium difficile toxin expression is inhibited by the novel regulator TcdC
Authors: Matamouros Susana , England Patrick , Dupuy Bruno 
Published: May 2007

Summary Clostridium difficile, an emerging nosocomial pathogen of increasing clinical significance, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The precise mechanisms by which toxin synthesis is regulated in response to environmental change have yet to be discovered. The toxin genes (tcdA and tcdB) are located in a pathogenicity locus (PaLoc), along with tcdR and tcdC. TcdR is an alternative RNA polymerase σ factor that directly activates toxin gene expression, while the inverse relationship between expression of tcdR, tcdA and tcdB genes on the one hand and tcdC on the other has led to the suggestion that TcdC somehow interferes with toxin gene expression. This idea is further supported by the finding that many recent C. difficile epidemic strains in which toxin production is increased carry a common tcdC deletion mutation. In this report we demonstrate that TcdC negatively regulates toxin synthesis both in vivo and in vitro. TcdC destabilizes the TcdR‐containing holoenzyme before open complex formation, apparently by interaction with TcdR or TcdR‐containing RNA polymerase holoenzyme or both. In addition, we show that the hypertoxigenicity phenotype of C. difficile epidemic strains is not due to their common 18 bp in‐frame deletion in tcdC.