427 research outputs found
Tephritids of knapweeds, starthistles and safflower: results of a host choice experiment and the taxonomy of Terellia luteola (Wiedemann) (Diptera: Tephritidae)
A host choice experiment was carried out to determine the host range of some potential biological control agents of yellow starthistle (Centaurea solstitialis), a Mediterranean plant which has become a serious rangeland weed in western USA. This paper describes the results of that experiment and discusses its taxonomic implications. The experiment confirmed the extreme host specificity of some species. However, two reputedly polyphagous species, Acanthiophilus helianthi (Rossi) and Urophora quadrifasciata (Meigen), attacked a narrower range of hosts than expected. The results of this and similar host choice experiments are discussed and it is concluded that this sort of anomaly can be caused by the existence of host races, unrecognized sibling species, or by varieties of plants naturally resistant to attack. These complex patterns of host relationship highlight the need to interpret host catalogue data cautiously, as they oversimplify complex biological systems. The identity of one species reared in the experiment, Terellia luteola (Wiedemann), is discussed; a key is presented for its separation from other Terellia species, and it is removed from synonymy with T. colon (Meigen
<i>Schizosaccharomyces pombe</i> Pol II transcription elongation factor ELL functions as part of a rudimentary super elongation complex
ELL family transcription factors activate the overall rate of RNA polymerase II (Pol II) transcription elongation by binding directly to Pol II and suppressing its tendency to pause. In metazoa, ELL regulates Pol II transcription elongation as part of a large multisubunit complex referred to as the Super Elongation Complex (SEC), which includes P-TEFb and EAF, AF9 or ENL, and an AFF family protein. Although orthologs of ELL and EAF have been identified in lower eukaryotes including Schizosaccharomyces pombe, it has been unclear whether SEClike complexes function in lower eukaryotes. In this report, we describe isolation from S. pombe of an ELL-containing complex with features of a rudimentary SEC. This complex includes S. pombe Ell1, Eaf1, and a previously uncharacterized protein we designate Ell1 binding protein 1 (Ebp1), which is distantly related to metazoan AFF family members. Like the metazoan SEC, this S. pombe ELL complex appears to function broadly in Pol II transcription. Interestingly, it appears to have a particularly important role in regulating genes involved in cell separation
Co-operation of BRCA1 and POH1 relieves the barriers posed by 53BP1 and RAP80 to resection
In G2 phase cells, DNA double-strand break repair switches from DNA non-homologous end-joining to homologous recombination. This switch demands the promotion of resection. We examine the changes in 53BP1 and RAP80 ionizing radiation induced foci (IRIF) in G2 phase, as these are factors that restrict resection. We observed a 2-fold increase in the volume of 53BP1 foci by 8 h, which is not seen in G1 cells. Additionally, an IRIF core devoid of 53BP1 arises where RPA foci form, with BRCA1 IRIF forming between 53BP1 and replication protein A (RPA). Ubiquitin chains assessed using a-FK2 antibodies
are similarly repositioned. Repositioning of all these components requires BRCA1’s BRCT but not the ring finger domain. 53BP1, RAP80 and ubiquitin chains are enlarged following POH1 depletion by small interfering RNA, but a devoid core does not form and RPA foci formation is impaired. Co-depletion of POH1 and RAP80, BRCC36 or ABRAXAS allows establishment of the 53BP1 and ubiquitin chain-devoid core. Thus, the barriers posed by 53BP1 and RAP80 are relieved by BRCA1 and POH1, respectively. Analysis of combined depletions shows that these represent distinct but interfacing barriers to promote loss of ubiquitin chains in the IRIF core, which is required for subsequent resection. We propose a model whereby BRCA1 impacts on 53BP1 to allow access of POH1 to RAP80. POH1-dependent removal of RAP80 within the IRIF core enables degradation of ubiquitin chains, which
promotes loss of 53BP1. Thus, POH1 represents a novel component regulating the switch from nonhomologous end-joining to homologous recombination
Host specificity of Aceria centaureae (Nalepa), a candidate for biological control of Centaurea dίffusa De Lamarck
Κατά τη διάρκεια των ετών 1985 και 1986 έγιναν πειράματα υπαίθρου με το άκαρι Acerea centaureae το οποίο προκαλεί κηκίδες (στα φύλλα κυρίως) του φυτού Centaurea diffusa.Προσβεβλημένα από το άκαρι τμήματα του φυτού C. diffusa τέθηκαν σε επαφή με πειραματικά φυτά ορισμένων ειδών που βρίσκονταν σε κατάλληλο στάδιο ανάπτυξης. Ακολούθησαν περιοδικοί έλεγχοι για τη διαπίστωση ύπαρξης προσβολής από το άκαρι στα πειραματικά φυτά. Παρατηρήθηκε δημιουργία κηκίδων σε όλα τα πειραματικά φυτάίΓ. diffusa είτε αυτά ήταν ελληνικής είτε βορειοαμερικανικής προέλευσης, καθώς και σε μερικά από τα πειραματικά φυτά του είδους Centaurea solstitialis L. Καμία κηκίδα ή άλλο σύμπτωμα προσβολής από το άκαρι δεν παρατηρήθηκε στα άλλα πειραματικά είδη φυτών τα οποία ήταν τα ακόλουθα: Carthamus tinctorius L., Circium creticum (De Lamarck) D'Urvilleελληνικής προέλευσης και έξι (6) είδη του γένους Cirsium βορειοαμερικανικήςπροέλευσης (Η.Π.Α.), τα: cymosum (Greene) Howell, occidentale (Nutt) Jeps,pastrris Howell, andersonii (Gray) Petrak, brevistylum Crong, και undulatum (Nutt.) Spreng.Τα αποτελέσματα αυτά υποδηλώνουν ότι πιθανότατα το άκαρι Aceria centaureae είναι μάλλον ολιγοφάγο είδος το οποίο προσβάλλει μόνον ορισμένα ζιζάνια του είδους Centaurea και επομένως μπορεί να θεωρηθεί ως υποψήφιο είδος για τη βιολογική καταπολέμηση του C. diffusa στις Η.Π.Α. και στον Καναδά.Filed collected rosettes or twigs of Centaurea diffusa De Lamarck, infested by the gall mite Aceria centaureae, were fixed onto appropriately grown and planted test plants of ten different species in the area of Thessaloniki, Greece, in 1985 and 1986. The test plants were inspected for presence of galls and mites a few to several days after their contact with the infested twigs. Gall formation occurred on all of the Centaurea diffusa test plants, either of Greek or U.S. origin, and on some of the Centaurea solstitialis, L. test plants. No galls or other mite damage could be found on the other test plants, which were Carthamus tinctorius L. (safflower), Cirsiton creticion (De Lamarck) D’Urville, of local origin and six Cirsium species of U.S. origin, i.e. cymosum (Greene) J. T. Howell, occidentals (Nutt) Jeps., pastoris Howell, andersonii (Gray) Petrak, brevistylum Crong; and undulation (Nutt.) Spreng. These results suggest that A. centaureae most probably has a very restricted host plant range, feeding only on weedy Centaurea spp. Thus the mite should be considered as a possible candidate for biological control of diffuse knapweed in the U.S.A. and Canada
Host specificity of Aceria centaureae (Nalepa), a candidate for biological control of Centaurea dίffusa De Lamarck
Κατά τη διάρκεια των ετών 1985 και 1986 έγιναν πειράματα υπαίθρου με το άκαρι Acerea centaureae το οποίο προκαλεί κηκίδες (στα φύλλα κυρίως) του φυτού Centaurea diffusa.Προσβεβλημένα από το άκαρι τμήματα του φυτού C. diffusa τέθηκαν σε επαφή με πειραματικά φυτά ορισμένων ειδών που βρίσκονταν σε κατάλληλο στάδιο ανάπτυξης. Ακολούθησαν περιοδικοί έλεγχοι για τη διαπίστωση ύπαρξης προσβολής από το άκαρι στα πειραματικά φυτά. Παρατηρήθηκε δημιουργία κηκίδων σε όλα τα πειραματικά φυτάίΓ. diffusa είτε αυτά ήταν ελληνικής είτε βορειοαμερικανικής προέλευσης, καθώς και σε μερικά από τα πειραματικά φυτά του είδους Centaurea solstitialis L. Καμία κηκίδα ή άλλο σύμπτωμα προσβολής από το άκαρι δεν παρατηρήθηκε στα άλλα πειραματικά είδη φυτών τα οποία ήταν τα ακόλουθα: Carthamus tinctorius L., Circium creticum (De Lamarck) D'Urvilleελληνικής προέλευσης και έξι (6) είδη του γένους Cirsium βορειοαμερικανικήςπροέλευσης (Η.Π.Α.), τα: cymosum (Greene) Howell, occidentale (Nutt) Jeps,pastrris Howell, andersonii (Gray) Petrak, brevistylum Crong, και undulatum (Nutt.) Spreng.Τα αποτελέσματα αυτά υποδηλώνουν ότι πιθανότατα το άκαρι Aceria centaureae είναι μάλλον ολιγοφάγο είδος το οποίο προσβάλλει μόνον ορισμένα ζιζάνια του είδους Centaurea και επομένως μπορεί να θεωρηθεί ως υποψήφιο είδος για τη βιολογική καταπολέμηση του C. diffusa στις Η.Π.Α. και στον Καναδά.Filed collected rosettes or twigs of Centaurea diffusa De Lamarck, infested by the gall mite Aceria centaureae, were fixed onto appropriately grown and planted test plants of ten different species in the area of Thessaloniki, Greece, in 1985 and 1986. The test plants were inspected for presence of galls and mites a few to several days after their contact with the infested twigs. Gall formation occurred on all of the Centaurea diffusa test plants, either of Greek or U.S. origin, and on some of the Centaurea solstitialis, L. test plants. No galls or other mite damage could be found on the other test plants, which were Carthamus tinctorius L. (safflower), Cirsiton creticion (De Lamarck) D’Urville, of local origin and six Cirsium species of U.S. origin, i.e. cymosum (Greene) J. T. Howell, occidentals (Nutt) Jeps., pastoris Howell, andersonii (Gray) Petrak, brevistylum Crong; and undulation (Nutt.) Spreng. These results suggest that A. centaureae most probably has a very restricted host plant range, feeding only on weedy Centaurea spp. Thus the mite should be considered as a possible candidate for biological control of diffuse knapweed in the U.S.A. and Canada
TRAIP/RNF206 is required for recruitment of RAP80 to sites of DNA damage
RAP80 localizes to sites of DNA insults to enhance the DNA-damage responses. Here we identify TRAIP/RNF206 as a novel RAP80-interacting protein and find that TRAIP is necessary for translocation of RAP80 to DNA lesions. Depletion of TRAIP results in impaired accumulation of RAP80 and functional downstream partners, including BRCA1, at DNA lesions. Conversely, accumulation of TRAIP is normal in RAP80-depleted cells, implying that TRAIP acts upstream of RAP80 recruitment to DNA lesions. TRAIP localizes to sites of DNA damage and cells lacking TRAIP exhibit classical DNA-damage response-defect phenotypes. Biochemical analysis reveals that the N terminus of TRAIP is crucial for RAP80 interaction, while the C terminus of TRAIP is required for TRAIP localization to sites of DNA damage through a direct interaction with RNF20-RNF40. Taken together, our findings demonstrate that the novel RAP80-binding partner TRAIP regulates recruitment of the damage signalling machinery and promotes homologous recombinationopen
The Fanconi anemia proteins FANCD2 and FANCJ interact and regulate each other's chromatin localization.
Fanconi anemia is a genetic disease resulting in bone marrow failure, birth defects, and cancer that is thought to encompass a defect in maintenance of genomic stability. Mutations in 16 genes (FANCA, B, C, D1, D2, E, F, G, I, J, L, M, N, O, P, and Q) have been identified in patients, with the Fanconi anemia subtype J (FA-J) resulting from homozygous mutations in the FANCJ gene. Here, we describe the direct interaction of FANCD2 with FANCJ. We demonstrate the interaction of FANCD2 and FANCJ in vivo and in vitro by immunoprecipitation in crude cell lysates and from fractions after gel filtration and with baculovirally expressed proteins. Mutation of the monoubiquitination site of FANCD2 (K561R) preserves interaction with FANCJ constitutively in a manner that impedes proper chromatin localization of FANCJ. FANCJ is necessary for FANCD2 chromatin loading and focus formation in response to mitomycin C treatment. Our results suggest not only that FANCD2 regulates FANCJ chromatin localization but also that FANCJ is necessary for efficient loading of FANCD2 onto chromatin following DNA damage caused by mitomycin C treatment
Untersuchungen über Bionomie, Präimaginalstadien und Verbreitung der europäischen Sorhagenia-Arten (Lepidoptera: Walshiidae).
Die Bionomien der europäischen Arten der Gattung Sorhagenia werden beschrieben. Die Raupe von Sorhagenia lophyrella Douglas lebt einzeln zwischen zusammengesponnenen Blättern von Rhamnus cathartica und Rhamnus saxatilis, die von Sorhagenia rhamniella Zeller gesellig zwischen zusammengesponnenen Blüten von Rhamnus cathartica, jene von Sorphagenia janiszewskae Ridl miniert in den disjährigen Trieben von Rhamnus frangula seltener in anderen Rhamnus-Arten. Sorphagenia lophyrella und Sorhagenia rhamniella überwintern als Ei, Sorhagenia janiszewskae vermutlich als Imago in beiden Geschlechtern. Nach dem Material aus Museen und Privatsammlungen sowie aus eigenen Aufsammlungen wird ein Überblick über die Verbreitung der Arten gegeben. Raupe und Puppe werden beschrieben und abgebildet, Unterscheidungsmerkmale der Raupen angegeben.The bionomics of the european species of the genus Sorhagenia are described. The caterpillar of Sorhagenia lophyrella Douglas lives singly between spun leaves of Rhamnus cathartica and Rhamnus saxatilis, that of Sorhagenia rhamniella Zeller lives sociably between spun blossoms of Rhamnus cathartica, that of Sorphagenia janiszewskae Ridl mines in this years shoots of Rhamnus frangula and more rarely in other species of Rhamnus. Sorphagenia lophyrella and Sorhagenia rhamniella hibernate as eggs, Sorhagenia janiszewskae probably as imago in both sexes. On the basis of material from museums and private collections and from the author's collections a survey is given of the distribution of the species. Caterpillar and pupa are described and illustrated, and distinctive characteristics of the caterpillars are mentioned
A new Eriophyid species (Acari Eriophyoidea) on Salsola spp. (Centrospermae Chenopodiaceae) and a new report for Aceria tamaricis (Trotter)
A new eriophyoid species is described and illustrated. Aceria salsolae n. sp. was observed on Salsola kali L. and S. australis Brown (Centrospermae Chenopodiaceae) in Turkey, Greece and Uzbekistan. Although the mite does not form galls, the infested plants were stunted, deformed, less spiny, and their vigor was impacted. Host specificity tests, carried out in Turkey, indicate that this species is a promising candidate for the biological control of S. australis in the U.S.A. A. tamaricis (Trotter) has been also found on Tamarix smirnensis Bunge in Turkey. Key words: mites, Eriophyidae, weeds, biological control. UNA NUOVA SPECIE DI ERIOFIDE (ACARI ERIOPHYOIDEA) SU SALSOLA SPP. (CENTROSPERMAE CHENOPODIACEAE) E UNA NUOVA SEGNALAZIONE PER ACERIA TAMARICIS (TROTTER) Viene descritta e illustrata una nuova specie di Eriofide. Aceria salsolae sp. n. è stata raccolta su Salsola kali L. e S. australis Brown (Centrospermae Chenopodiaceae), in Turchia, Grecia e Uzbekistan. Le piante infestate mostravano crescita stentata, deformazioni, minore spinosità e ridotto vigore. Prove di specificità dell’ospite, eseguite in Turchia, hanno evidenziato come que- sta specie sia un promettente candidato per il suo controllo di S. australis negli U.S.A. A. tamaricis (Trotter) viene segnalata per la prima volta su Tamarix smirnensis Bunge in Turchia. Parole chiave: acari, Eriophyidae, erbe infestanti, controllo biologico
Taxonomy, distribution, and host specificity of a gall-making mite, Aceria tamaricis (Trotter) (Acari: Eriophyoidea), associated with Tamarix gallica L. (Parietales: Tamaricaceae) in southern France
A population of Aceria tamaricis (Trotter), found in galls collected on Tamarix gallica L. from southern France, has been compared to samples used for the redescription of the species by CASTAGNOLI (1992), pointing out the morphological differences, and to the other species found until now on Tamarix spp., making some taxonomic considerations. The host specificity study reveals that A. tamaricis almost always infests T. gallica while it does not attack T. aphylla (L.) Carsten from USA, T. parviflora D.C. from France and T. ramosis- sima Ledeb from USA. In addition, observations are presented on the biology and distribution of the mite in southern France. Key words: morphology, weeds, biological control. TASSONOMIA, DISTRIBUZIONE E SPECIFICITÀ DI UN ERIOFIDE GALLIGENO, ACERIA TAMARICIS (TROTTER) (ACARI: ERIOPHYOIDEA), ASSOCIATO A TAMARIX GALLICA L. (PARIETALES: TAMARICACEAE) IN FRANCIA MERIDIONALE Sono riportate le caratteristiche morfologiche di una popolazione di Aceria tamaricis (Trotter), galligeno su Tamarix gallica L. in Francia meridionale, e confrontate con quella utilizzata per la ridescrizione della specie eseguita da CASTAGNOLI (1992), evidenziando le differenze, e con le altre specie finora note su Tamarix spp. Lo studio della specificità ha rilevato che A. tamaricis infesta quasi sempre T. gallica mentre non attacca T. aphylla (L.) Carsten, T. parviflora D.C. e T. ramosissima Ledeb. Sono state eseguite, inoltre, osservazioni sulla biologia e distribuzione geografica in Francia meridionale. Parole chiave: morfologia, infestanti, controllo biologico
- …
