1,720,985 research outputs found
Can the two carboxypeptidase inhibitors of tomato act as signalling peptides during fruit development?
No full textThe tomato TCMP-1 and TCMP-2 genes code for metallocarboxypeptidase inhibitors, a subclass of the cystine-knot peptides family. The two transcripts display a sequential expression during flower/fruit development, with TCMP-1 highly expressed in flower buds before anthesis and TCMP-2 in ripe fruits. The alteration of their endogenous levels by expressing the TCMP-1 coding sequence under the control of the TCMP-2 promoter revealed that their relative levels are crucial for the fruit set timing (Molesini et al., 2018). The two mature TCMPs are 32% identical and highly similar in structure to the potato carboxypeptidase inhibitor (PCI). Both TCMPs and PCI share structural homology with some mammalian growth factors such as the epidermal growth factor (EGF) and vascular epidermal growth factor (VEGF), and are bioactive in mammalian cells. PCI competes with EGF for the binding to EGF receptor, inhibiting its activation (Blanco-Aparicio et al., 1998); TCMPs inhibit angiogenesis both in vitro in human umbilical vascular cells and in vivo in zebrafish by affecting the VEGF receptor activation (Cavallini et al., 2011; Treggiari et al., 2015). Thus, TCMPs can interfere with growth factor signalling pathways in animal cells. We can speculate that TCMPs could exert a similar activity also in plant cells. By sequence comparison we searched for plant receptors containing extracellular EGF-like domains that could represent good candidates for TCMPs recognition. EGF repeats in plants are found in receptor-like kinases of the wall-associated kinases-type (WAKs-type) and S-locus receptor kinases-type (SRKs-type). WAK and SRK members are shown to be involved in stress responses but also in growth and development
Peach (Prunus persica L.)
No full textUntil now, the application of genetic transformation techniques in peach has been limited by the difficulties in developing efficient regeneration and transformation protocols. Here we describe an efficient regeneration protocol for the commercial micropropagation of GF677 rootstock (Prunus persica × Prunus amygdalus). The method is based on the production, via organogenesis, of meristematic bulk tissues characterized by a high competence for shoot regeneration. This protocol has also been used to obtain GF677 plants genetically engineered with an empty hairpin cassette (hereafter indicated as hp-pBin19), through Agrobacterium tumefaciens-mediated transformation. After 7-8 months of selection on media containing kanamycin, we obtained two genetically modified GF677 lines. PCR and Southern blot analyses were performed to confirm the genetic status
MEDICAGO TRUNCATULA ROOTS OVEREXPRESSING THE NSLTP N5 DISPLAY MODIFICATIONS IN THE LIPID PROFILE AND CHANGES IN THE EXPRESSION OF GENES INVOLVED IN LIPID METABOLISM AFTER SINORHIZOBIUM MELILOTI INFECTION
No full textTo shed light on the of MtN5 during early symbiotic events, we investigated the metabolic pathways for lipid production associated with the MtN5overespression. We carried out a comparative transcriptomic analysis of MtN5overexpressing (MtN5ox) and wild type roots after 72h of Sinorhizobium meliloti inoculation; in the same experimental conditions, we assayed the effects of MtN5 overexpression on the root lipid profile. In MtN5ox roots, we identified a quite relevant number of differential expressed genes involved in lipid transport and metabolism. The major changes were detected in genes implicated in phopholipid signalling pathways such as myo-inositol 1-phosphate synthases, phosphatidylinositolspecific phospholipase, phosphatidylinositol kinases, phosphatidylinositol transfer protein, inositol mono-phosphatase. All these transcripts were down-regulated in inoculated MtN5ox roots. Interestingly we demonstrated that MtN5 functioning is dependent on phospholipase D but not on phospholipase C activity (Pii et al., 2012). The analysis of the root lipid fraction revealed that MtN5 overexpressing roots displayed a general increase in the lipid content, that was especially relevant for galactolipids that are component of plastid and symbiosome membranes
TOMATO KNOTTIN TCMP-1 PLAYS A ROLE IN CADMIUM TOLERANCE
No full textKnottins or cystine-knot miniproteins (CMPs) are a class of cysteine (Cys)-rich proteins identified in eukaryotes. They are characterized by a very small size and by the presence of a C-terminal knot domain with six conserved Cys forming three disulfide bonds, conferring stability and resistance to high temperatures, proteolysis and chemical chaotropic agents. In plants, members of the knottin family participate in defense against pathogens and herbivores acting as inhibitors of proteases or amylases or displaying antimicrobial and insecticidal properties (Daly & Craik, 2011). Moreover, knottins have been found as associated with nickel (Ni) tolerance in a Ni-hyperaccumulator ecotype of Noccaea caerulescens (Halimaa et al., 2014) and with cadmium (Cd) accumulation in tobacco (Harada et al., 2010). Due to their biological activity, knottins have been considered for their potential application for therapeutical purposes: in particular, two tomato CMPs, TCMP-1 and TCMP-2, are able to inhibit angiogenesis without affecting endothelial cell proliferation and viability, both in vitro and in vivo, and to reduce cell migration (Treggiari et al., 2015). In tomato plants, TCMP-1 and TCMP-2 expression is strictly regulated and associated with flower buds before anthesis and ripe fruits, respectively. This evidence, as well as the earlier fruit setting observed when perturbing TCMP-1 expression, indicate a role in fruit development (Molesini et al., 2018)
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
Genome-Wide Transcriptional Changes and Lipid Profile Modifications Induced by Medicago truncatula N5 Overexpression at an Early Stage of the Symbiotic Interaction with Sinorhizobium meliloti.
Full text linkPlant lipid-transfer proteins (LTPs) are small basic secreted proteins, which are characterized by lipid-binding capacity and are putatively involved in lipid trafficking. LTPs play a role in several biological processes, including the root nodule symbiosis. The Medicago truncatula nodulin 5 (MtN5) LTP has been proved to positively regulate the nodulation capacity, controlling rhizobial infection and nodule primordia invasion. To better define the lipid transfer protein MtN5 function during the symbiosis, we produced MtN5-downregulated and -overexpressing plants, and we analysed the transcriptomic changes occurring in the roots at an early stage of Sinorhizobium meliloti infection. We also carried out the lipid profile analysis of wild type (WT) and MtN5-overexpressing roots after rhizobia infection. The downregulation of MtN5 increased the root hair curling, an early event of rhizobia infection, and concomitantly induced changes in the expression of defence-related genes. On the other hand, MtN5 overexpression favoured the invasion of the nodules by rhizobia and determined in the roots the modulation of genes that are involved in lipid transport and metabolism as well as an increased content of lipids, especially galactolipids that characterize the symbiosome membranes. Our findings suggest the potential participation of LTPs in the synthesis and rearrangement of membranes occurring during the formation of the infection threads and the symbiosome membrane
Utilizzo del sistema CRISPR/Cas9 per ottenere partenocarpia in pomodoro
No full textCon genome editing s’intende l’introduzione di una modifica in un punto preciso del genoma della cellula attraverso l’utilizzo di nucleasi artificiali che operano sul gene bersaglio una rottura, la cui riparazione può generare mutazioni ed annullare la funzione del gene. Il sistema più diffuso è quello CRISPR/Cas9 di Streptococcus pyogenes, e prevede che una DNA nucleasi (Cas9) venga guidata ad una sequenza di DNA da modificare, grazie alla sua associazione con una piccola molecola di RNA (RNA guida) in grado di appaiarsi alla sequenza bersaglio. L’allegagione, l’inizio della crescita dell’ovario a seguito della fecondazione, è un processo coordinato da segnali endogeni, soprattutto ormonali, ma che risente di fattori ambientali, che se sfavorevoli, possono avere effetti negativi sulla fecondazione e sulla produttività. Numerosi geni che controllano l’allegagione sono stati individuati. La partenocarpia è un processo alternativo in cui lo sviluppo del frutto avviene in assenza di fecondazione ed indipendentemente dalle condizioni ambientali. La manipolazione genetica del metabolismo e della trasduzione del segnale dell’auxina e delle gibberelline ha permesso di identificare i geni che controllano la partenocarpia. Nel presente studio, il sistema CRISPR è stato usato per indurre mutazioni nel gene SlARF7, noto per essere un regolatore dello sviluppo partenocarpico del frutto di pomodoro. Tre sequenze nucleotidiche corrispondenti a 3 RNA guida aventi come bersaglio 3 regioni diverse del gene SlARF7 sono state clonate nel T-DNA di un vettore binario pFGC-pcoCAS9 (https://www.addgene.org; Li et al., 2013). L’efficacia dei tre RNA del costrutto nell’indurre il taglio nel gene ARF7- RNA guida mediato, è stata testata in vitro attraverso l’impiego del kit commerciale “Guide-it sgRNA in vitro Transcription and Screening Systems” (Clontech). Il vettore binario è stato poi inserito in Agrobacterium tumefaciens (ceppo GV2260) ed impiegato per indurre mutazioni nella cv. UC8
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