Search results for "Tabac"
showing 10 items of 131 documents
Involvement of Free Calcium in Action of Cryptogein, a Proteinaceous Elicitor of Hypersensitive Reaction in Tobacco Cells
1995
Treatment of suspension-cultured tobacco (Nicotiana tabacum var Xanthi) cells with cryptogein, a proteinaceous elicitor from Phytophthora cryptogea, induced a great stimulation of Ca2+ influx within the first minutes. Ca2+ influx is essential for the initiation of cryptogein-induced responses, since ethyleneglycol-bis([beta]-amino-ethyl ether)-N,N[prime]-tetraacetic acid or La3+, which block Ca2+ entrance, suppress cryptogein-induced responses such as extracellular alkalinization, active oxygen species, and phytoalexin production. Moreover, once initiated, these responses require sustained Ca2+ influx within the 1st h. A Ca2+ ionophore (A23187) was able to trigger an extracellular alkaliniz…
Protein phosphorylation is induced in tobacco cells by the elicitor cryptogein
1994
Changes in plasmalemma ion fluxes were observed when tobacco (Nicotiana tabacum) cells were treated with cryptogein, a proteinaceous elicitor from Phytophthora cryptogea. A strong alkalization of the culture medium, accompanied by a leakage of potassium, was induced within a few minutes of treatment. These effects reached a maximum after 30 to 40 min and lasted for several hours. This treatment also resulted in a rapid, but transient, production of activated oxygen species. All these physiological responses were fully sensitive to staurosporine, a known protein kinase inhibitor. Furthermore, a study of protein phosphorylation showed that cryptogein induced a staurosporine-sensitive phosphor…
The plasma membrane oxidase NtrbohD is responsible for AOS production in elicited tobacco cells
2002
Summary A cDNA encoding a protein, NtrbohD, located on the plasma membrane and homologue to the flavocytochrome of the neutrophil NADPH oxidase, was cloned in tobacco. The corresponding mRNA was accumulated when tobacco leaves and cells were treated with the fungal elicitor cryptogein. After elicitation with cryptogein, tobacco cells transformed with antisense constructs of NtrbohD showed the same extracellular alkalinization as the control, but no longer produced active oxygen species (AOS). This work represents the first demonstration of the function of a homologue of gp91–phox in AOS production in elicited tobacco cells.
Cytosolic calcium rises and related events in ergosterol-treated Nicotiana cells
2011
International audience; The typical fungal membrane component ergosterol was previously shown to trigger defence responses and protect plants against pathogens. Most of the elicitors mobilize the second messenger calcium, to trigger plant defences. We checked the involvement of calcium in response to ergosterol using Nicotiana plumbaginifolia and Nicotiana tabacum cv Xanthi cells expressing apoaequorin in the cytosol. First, it was verified if ergosterol was efficient in these cells inducing modifications of proton fluxes and increased expression of defence-related genes. Then, it was shown that ergosterol induced a rapid and transient biphasic increase of free [Ca2þ]cyt which intensity dep…
Physiological and Structural Changes in Tobacco Leaves Treated with Cryptogein, a Proteinaceous Elicitor fromPhytophthora cryptogea
1991
Cryptogein was applied on the petiole section of excised tobacco leaves. It elicited necroses that can be correlated with histological alterations, such as rapid chloroplast breakdown and a collapse of cells leading to disorganization of the parenchyma tissue. In addition, it induced ethylene production and accumulation of capsidiol. In order to detect an early response, we analyzed the kinetics of chlorophyll fluorescence induction (...)
Early changes in gene expression in tobacco cells elicited with cryptogein
1995
48 ref.; International audience
The fungal elicitor cryptogein induces cell wall modifications on tobacco cell suspension
2000
Upon addition of the fungal elicitor cryptogein, suspension cells of tobacco (Nicotiana tabacum cv. Xanthi) aggregated in clusters. Cytochemical experiments indicated that elicited cells displayed fibrillar expansions of pectin along the primary cell wall. Immunocytochemical detection of pectin epitopes indicated that the fibrillar material surrounding the treated cells was mostly composed of low methylated galacturonan sequences, but the use of the cationic probe did not reveal the presence of negatively charged carboxyl groups: the presence of important amounts of calcium ions in these pectic fibrillar expansions accounts for these observations. These data indicate that tobacco cells trea…
Early signaling events induced by elicitors of plant defenses
2006
International audience; Plant pathogen attacks are perceived through pathogenissued compounds or plant-derived molecules that elicit defense reactions. Despite the large variety of elicitors, general schemes for cellular elicitor signaling leading to plant resistance can be drawn. In this article, we review early signaling events that happen after elicitor perception, including reversible protein phosphorylations, changes in the activities of plasma membrane proteins, variations in free calcium concentrations in cytosol and nucleus, and production of nitric oxide and active oxygen species. These events occur within the first minutes to a few hours after elicitor perception. One specific eli…
Rifampicin treatment of Blattella germanica evidences a fecal transmission route of their gut microbiota
2018
Eukaryotes have established symbiotic relationship with microorganisms, which enables them to accomplish functions that they cannot perform alone. In the German cockroach, Blattella germanica, the obligate endosymbiont Blattabacterium coexists with a rich gut microbiota. The transmission of Blattabacterium is vertical, but little is known about how the gut microbiota colonizes newborn individuals. In this study, we treated B. germanica populations with rifampicin, a broad-spectrum antibiotic, during two generations and analyzed gut bacterial composition and the Blattabacterium load in control and rifampicin-treated populations. Rifampicin exerted a drastic effect on gut microbiota compositi…
Genome-wide DNA methylation study in human placenta identifies novel loci associated with maternal smoking during pregnancy
2016
BACKGROUND: We conducted an epigenome-wide association study (EWAS) of DNA methylation in placenta in relation to maternal tobacco smoking during pregnancy and examined whether smoking-induced changes lead to low birthweight. METHODS: DNA methylation in placenta was measured using the Illumina HumanMethylation450 BeadChip in 179 participants from the INfancia y Medio Ambiente (INMA) birth cohort. Methylation levels across 431 311 CpGs were tested for differential methylation between smokers and non-smokers in pregnancy. We took forward three top-ranking loci for further validation and replication by bisulfite pyrosequencing using data of 248 additional participants of the INMA cohort. We ex…