1,720,980 research outputs found
Bap170, a Subunit of the Drosophila PBAP Chromatin Remodeling Complex, Negatively Regulates the EGFR Signaling
No full textBAP and PBAP constitute the two different forms of the Drosophila melanogaster Brahma chromatin remodelers. A common multisubunit core, containing the Brahma ATPase, can associate either with Osa to form the BAP complex or with Bap170, Bap180, and Sayp to constitute the PBAP complex. Although required for many biological processes, recent genetic analyses revealed that one role of the BAP complex during Drosophila wing development is the proper regulation of EGFR target genes. Here, we show that Bap170, a distinctive subunit of the PBAP complex, participates instead in the negative regulation of EGFR signaling. In adults, loss of Bap170 generates phenotypes similar to the defects induced by hyperactivation of the EGFR pathway, such as overrecruitment of cone and photoreceptor cells and formation extra veins. In genetic interactions, bap170 mutations suppress the loss of veins and photoreceptors caused by mutations affecting the activity of the EGFR pathway. Our results suggest a dual requirement of the PBAP complex: for transcriptional repression of rhomboid and for efficient expression of argos. Interestingly, genetic evidence also indicates that Bap170-mediated repression of rho is inhibited by EGFR signaling, suggesting a scenario of mutual antagonism between EGFR signaling and PBAP function
Cuticle-degrading protease and toxins as virulence markers of Beauveria bassiana (Balsamo) Vuillemin
No full textBeauveria bassiana is one of the most known entomopathogenic fungal species and its
entomopathogenic mechanism involves several bioactive metabolites, mainly cuticle-degrading
enzymes and toxic molecules, which are predicted to play a key role as virulence factors. In this
study six Beauveria bassiana strains (B 13/I03, B 13/I11, B 13/I49, B 13/I57, B 13/I63, and B 13/I64)
were assayed against Tenebrio molitor larvae. Enzymatic activity of total proteases and specifically
Pr 1 and Pr 2, as well as the production of toxic compounds were investigated in each fungal
strain. Toxins were detected both in vitro—in medium filtrates and mycelia—and in vivo—in
Tenebrio molitor larvae infected by the fungal strains tested. B 13/I11 and B 13/I63 strains showed
the most significant entomopathogenic activity against Tenebrio molitor larvae (cumulative
mortality rate 100 and 97%, respectively; average survival time 5.85 and 6.74 days, respectively).
A widely variable and fungal strain-dependent enzymatic activity of total proteases, Pr 1 and Pr 2
was found. Beauvericin, beauvericin A and bassianolide resulted the most prevalent toxins
detected in the substrates analyzed. It has been found that an increase of beauvericin content in
vivo resulted significantly correlated to a decrease of Tenebrio molitor larvae average survival time
in entomopathogenic bioassay (inverse correlation). The involvement of beauvericin in B. bassiana
entomopathogenic process is confirmed; in vitro analysis of cuticle degrading proteases activity
and toxins production in relation to the methods adopted resulted insufficient for a rapid
screening to determine the virulence of B. bassiana strains against Tenebrio molitor larvae
Report of the first finding of Bursaphelenchus poligraphi and B. paraleoni in Italy
No full textBark beetles play an important ecological role in forest ecosystems, but under certain conditions, they can become a serious phytosanitary threat to host plants. This risk increases in the presence of environmental stress factors linked to climate change, such as heavy snowfall, strong winds, and prolonged drought periods.
This study focused on weakened or declining stands of Norway spruce (Picea abies) in the Apennines, specifically in the areas of Abetone (Tuscany) and Montedimezzo (Molise), affected by infestations of the beetle Polygraphus poligraphus L. (Coleoptera: Curculionidae, Scolytinae).
During monitoring activities carried out in 2024, samples of wood, bark, and adult beetles were collected from infested trees.
To investigate the possible presence of associated nematodes, the wood and bark samples were processed using the Oostenbrink dish method, while the adult insects were examined through direct observation under a stereomicroscope.
The analyses led to the identification of two nematode species never before reported in Italy: Bursaphelenchus poligraphi, isolated from both wood and adult beetles — previously known only in France, Germany, Romania, and Slovakia — and Bursaphelenchus paraleoni, found in wood samples from Molise, until now, only been reported in China, where it was intercepted in wood imported from the United States
Segnalazione del primo ritrovamento di Bursaphelenchus poligraphi associato a Polygraphus poligraphus in Italia
No full textI cambiamenti climatici, caratterizzati da eventi estremi come intense nevicate, venti forti e prolungate siccità, hanno indebolito le
foreste di abete rosso (Picea abies) in Italia, rendendole così più vulnerabili agli attacchi di coleotteri scolitidi autoctoni, tipicamente
associati a questa conifera, quali Ips typographus e Pityogenes chalcographus. I coleotteri scolitidi hanno un ruolo ecologico
significativo nelle foreste, che tuttavia può trasformarsi in una minaccia fitosanitaria per le piante ospiti, specialmente in condizioni
di stress ambientali.
In questo lavoro è stata posta l’attenzione sulla specie Polygraphus poligraphus L. (Coleoptera Curculionidae Scolytinae), associata
per la prima volta all’abete rosso in popolamenti appenninici quali Abetone (Regione Toscana) e Montedimezzo (Regione Molise), sia
in aree naturali che in piantagioni artificiali, evidenziando la sua capacità di espandersi in diversi ambienti. Inoltre, la sua azione
sinergica con le specie di scolitidi sopraccitati ha contribuito al declino dell’abete rosso, specialmente in popolamenti situati al di
fuori del loro areale naturale e quindi più vulnerabili.
Durante i monitoraggi condotti nel 2024 per la valutazione dello stato fitosanitario di popolamenti di abete rosso nel territorio
appenninico, sono stati prelevati campioni di legno e corteccia e di insetti adulti di P. poligraphus su piante che mostravano attacchi
dello scolitide. I campioni raccolti sono stati analizzati presso il Laboratorio di Nematologia del CREA-DC di Firenze. Per valutare
l’eventuale presenza di nematodi, i campioni di legno e corteccia sono stati estratti mediante il metodo delle bacinelle di
Oostenbrink e gli insetti sono stati esaminati tramite osservazione diretta allo stereomicroscopio.
Dal legno proveniente dal sito toscano (Abetone) e dal legno e dagli insetti adulti raccolti in Molise è stato estratto, per la prima
volta in Italia, il nematode Bursaphelenchus poligraphi Fuchs (1937), appartenente al gruppo sexdentati e noto finora solo in Francia,
Germaniania e Slovacchia. L’identificazione della specie è stata realizzata tramite analisi morfologica e molecolare. Le misurazioni
effettuate su esemplari maschi e femmine sono conformi a quelle riportate in letteratura.
Questo ritrovamento conferma il legame tra nematode-scolitide, come evidenziato in letteratura. In particolare, lo scolitide P.
poligraphus è già riconosciuto come il principale vettore del nematode B. poligraphi
Use of Heterorhabditis bacteriophora for the biological control of Popillia japonica larvae and evaluation of its impact on non-target soil biota
No full textPopillia japonica (Coleoptera: Scarabaeidae) is a scarab beetle native to Japan and accidentally introduced to Italy from North America in 2014. The high reproductive rate, the pathway of introduction, and the dispersal capability, as well as the polyphagous diet, led the EU to include this pest in the priority list. Popillia japonica spends most of its life cycle as a grub in the soil. At this stage, the grubs damage turf grasses, hay meadows, soccer pitches, and golf courses and are susceptible to biological control agents present in the soil, such as entomopathogenic nematodes (EPNs). As part of the Horizon 2020 Project ‘IPM-POPILLIA’, a large number of natural EPN strains have been collected from the soil in the outbreak area in Northern Italy along the Ticino River. The most virulent indigenous strain of Heterorhabditis bacteriophora (POP 16) was used in field trials to assess its effectiveness in containing the P. japonica larval population and its persistence in soil. Since September 2021, these trials have been carried out in the Piedmont region in three meadows with different irrigation management (non-irrigated, semi-irrigated, and irrigated fields). Two months after the treatments, a significant reduction of P. japonica larvae was observed in plots treated with EPNs (>90%) compared to untreated ones. Regarding persistence, H. bacteriophora was isolated again after the winter season and at lower concentrations one and two years after treatments, depending on irrigation management. Furthermore, in the irrigated meadow, the effects of EPNs on non-target soil biota were also evaluated, comparing soil arthropod assemblages with a Before-After Control-Impact experimental design. Compared to the control, no evident negative effect on non-target edaphic arthropods was disclosed on soil treated with EPNs. However, some taxa showed an increase in abundance, suggesting that some changes may occur in the long term. These results evidenced that the use of the selected EPN indigenous strain may be an excellent candidate for the integrated management of P. japonica, with no impact on non-target species, and at the same time highlighting the importance of evaluating the effects on soil biota to preserve the key- functioning of the ecosystem
Stoccaggio di uova ospiti a basse e ultrabasse temperature e studi preliminari sulla crioconservazione degli Imenotteri ooparassitoidi
No full textArtropodi e Nematodi comprendono una quota preponderante del numero di specie animali del nostro pianeta e gli studi svolti nell’ambito del Dottorato si inseriscono in un quadro generale di ricerche sulla crioconservazione, avviate a partire dal 2005 presso il Centro di Ricerca per l’Agrobiologia e la Pedologia di Firenze del CRA, mirate alla definizione di materiali e procedure di permeabilizzazione specie-specifiche e all’identificazione degli stadi ottimali per trattamenti di vitrificazione di organismi inclusi in questi due Phyla, con il fine ultimo di realizzare le condizioni per la creazione di “banche genetiche crioconservate”, nelle quali stoccare a lungo termine specie di interesse agroforestale e ambientale (Irdani et al. 2006; Cosi et al. 2008; Irdani et al. 2011; Roversi et al. 2013).
Le indagini di cui si riferisce hanno riguardato 2 sistemi modello:
1. Fitofago ospite: Leptoglossus occidentalis Heidemann (Heteroptera Coreidae)
• Ooparassitoide: Gryon pennsylvanicum (Ashmead) (Hymenoptera Platygastridae)
2. Fitofago ospite: Galleria mellonella (L.) (Lepidoptera Pyralidae)
• Ooparassitoide: Trichogramma brassicae (Bezdenko) (Hymenoptera Trichogrammatidae).
Nel primo sistema, dopo la caratterizzazione molecolare del ceppo di Gryon pennsylvanicum (Ashmead), introdotto in Europa dal Canada nell’ambito di un programma di “lotta biologica classica” (Roversi et al. 2011), con riferimento alle due problematiche sopracitate, sono state valutate sia le potenzialità di stoccaggio delle uova di Leptoglossus occidentalis per il successivo utilizzo per la parassitizzazione da parte del Platigastride che le possibilità di permeabilizzazione del corion delle uova del Coreide, quale primo passo per la messa a punto di un protocollo di crioconservazione per uova di ospiti contenenti embrioni di Imenotteri endoparassitoidi, attualmente non disponibile per nessuna specie di questo gruppo.
Nel secondo sistema è stata verificata la possibilità di applicare la modalità di permeabilizzazione inserita nel protocollo di crioconservazione messo a punto per gli embrioni di Galleria mellonella (L.) (Roversi et al. 2008), per il trattamento di uova di questo lepidottero contenenti embrioni dell’ooparassitoide Trichogramma brassicae (Bezdenko)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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