Environmental Control of Phase Transition and Polyp Survival of a Massive-Outbreaker Jellyfish

A number of causes have been proposed to account for the occurrence of gelatinous zooplankton (both jellyfish and ctenophore) blooms. Jellyfish species have a complex life history involving a benthic asexual phase (polyp) and a pelagic sexual phase (medusa). Strong environmental control of jellyfish life cycles is suspected, but not fully understood. This study presents a comprehensive analysis on the physicochemical conditions that control the survival and phase transition of Cotylorhiza tuberculata; a scyphozoan that generates large outbreaks in the Mediterranean Sea. Laboratory experiments indicated that the influence of temperature on strobilation and polyp survival was the critical factor controlling the capacity of this species to proliferate. Early life stages were less sensitive to other factors such as salinity variations or the competitive advantage provided by zooxanthellae in a context of coastal eutrophication. Coherently with laboratory results, the presence/absence of outbreaks of this jellyfish in a particular year seems to be driven by temperature. This is the first time the environmental forcing of the mechanism driving the life cycle of a jellyfish has been disentangled via laboratory experimentation. Projecting this understanding to a field population under climatological variability results in a pattern coherent with in situ records

Mental health of UK hospitality Workers: Shame, self-criticism and self-reassurance

This study aimed to evaluate shame for mental health problems, and explore relationships between shame, self-criticism, self-reassurance, and mental health among UK hospitality workers, because this group of workers suffer from poor mental health yet report strong shame. An opportunity sample of 114 UK hospitality workers completed measures examining shame for mental health problems, self-criticism, self-reassurance, and mental health problems. A high proportion of workers scored over the midpoint in almost all the shame subscales. Shame, self-criticism, self-reassurance, and mental health were related to one another. External shame and self-criticism were positive predictors, and self-reassurance was a negative predictor for mental health problems. While self-criticism moderated the relationship between shame and mental health problems, self-reassurance did not. Online compassion training was recommended as it can reduce self-criticism and shame, can be undertaken without colleagues knowing and tailored to specific work patterns.N/

Bimodal dynamics of primary metabolism-related responses in tolerant potato-Potato virus Y interaction

BACKGROUND: Potato virus Y (PVY) is a major pathogen that causes substantial economic losses in worldwide potato production. Different potato cultivars differ in resistance to PVY, from severe susceptibility, through tolerance, to complete resistance. The aim of this study was to better define the mechanisms underlying tolerant responses of potato to infection by the particularly aggressive PVY(NTN) strain. We focused on the dynamics of the primary metabolism-related processes during PVY(NTN) infection. RESULTS: A comprehensive analysis of the dynamic changes in primary metabolism was performed, which included whole transcriptome analysis, nontargeted proteomics, and photosynthetic activity measurements in potato cv. Désirée and its transgenic counterpart depleted for accumulation of salicylic acid (NahG-Désirée). Faster multiplication of virus occurred in the NahG-Désirée, with these plants developing strong disease symptoms. We show that while the dynamics of responses at the transcriptional level are extensive and bimodal, this is only partially translated to the protein level, and to the final functional outcome. Photosynthesis-related genes are transiently induced before viral multiplication is detected and it is down-regulated later on. This is reflected as a deficiency of the photosynthetic apparatus at the onset of viral multiplication only. Interestingly, specific and constant up-regulation of some RuBisCO transcripts was detected in Désirée plants, which might be important, as these proteins have been shown to interact with viral proteins. In SA-deficient and more sensitive NahG-Désirée plants, consistent down-regulation of photosynthesis-related genes was detected. A constant reduction in the photochemical efficiency from the onset of viral multiplication was identified; in nontransgenic plants this decrease was only transient. The transient reduction in net photosynthetic rate occurred in both genotypes with the same timing, and coincided with changes in stomatal conductivity. CONCLUSIONS: Down-regulation of photosynthesis-related gene expression and decreased photosynthetic activity is in line with other studies that have reported the effects of biotic stress on photosynthesis. Here, we additionally detected induction of light-reaction components in the early stages of PVY(NTN) infection of tolerant interaction. As some of these components have already been shown to interact with viral proteins, their overproduction might contribute to the absence of symptoms in cv. Désirée. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1925-2) contains supplementary material, which is available to authorized users

Potato virus Y

In the field, plants are challenged by more than one biotic stressor at the same time. In this study, the molecular interactions between potato (Solanum tuberosum L.), Colorado potato beetle (Leptinotarsa decemlineata Say; CPB) and Potato virus YNTN (PVYNTN) were investigated through analyses of gene expression in the potato leaves and the gut of the CPB larvae, and of the release of potato volatile compounds. CPB larval growth was enhanced when reared on secondary PVYNTN-infected plants, which was linked to decreased accumulation of transcripts associated with the antinutritional properties of potato. In PVYNTN-infected plants, ethylene signalling pathway induction and induction of auxin response transcription factors were attenuated, while no differences were observed in jasmonic acid (JA) signalling pathway. Similarly to rearing on virus-infected plants, CPB larvae gained more weight when reared on plants silenced in JA receptor gene (coi1). Although herbivore-induced defence mechanism is regulated predominantly by JA, response in coi1-silenced plants only partially corresponded to the one observed in PVYNTN-infected plants, confirming the role of other plant hormones in modulating this response. The release of β-barbatene and benzyl alcohol was different in healthy and PVYNTN-infected plants before CPB larvae infestation, implicating the importance of PVYNTN infection in plant communication with its environment. This was reflected in gene expression profiles of neighbouring plants showing different degree of defence response. This study thus contributes to our understanding of plant responses in agro-ecosystems

Potato virus Y infection hinders potato defence response and renders plants more vulnerable to Colorado potato beetle attack

In the field, plants are challenged by more than one biotic stressor at the same time. In this study, the molecular interactions between potato (Solanum tuberosum L.), Colorado potato beetle (Leptinotarsa decemlineata Say; CPB) and Potato virus YNTN (PVYNTN) were investigated through analyses of gene expression in the potato leaves and the gut of the CPB larvae, and of the release of potato volatile compounds. CPB larval growth was enhanced when reared on secondary PVYNTN-infected plants, which was linked to decreased accumulation of transcripts associated with the antinutritional properties of potato. In PVYNTN-infected plants, ethylene signalling pathway induction and induction of auxin response transcription factors were attenuated, while no differences were observed in jasmonic acid (JA) signalling pathway. Similarly to rearing on virus-infected plants, CPB larvae gained more weight when reared on plants silenced in JA receptor gene (coi1). Although herbivore-induced defence mechanism is regulated predominantly by JA, response in coi1-silenced plants only partially corresponded to the one observed in PVYNTN-infected plants, confirming the role of other plant hormones in modulating this response. The release of β-barbatene and benzyl alcohol was different in healthy and PVYNTN-infected plants before CPB larvae infestation, implicating the importance of PVYNTN infection in plant communication with its environment. This was reflected in gene expression profiles of neighbouring plants showing different degree of defence response. This study thus contributes to our understanding of plant responses in agro-ecosystems

Assessment of SNaPshot and single step RT-qPCR methods for discriminating Potato virus Y (PVY) subgroups

Equipe 6International audiencePotato virus Y(PVY) is the most important virus infecting potato (Solanum tuberosum), causing potato tuber necrotic ringspot disease (PTNRD), with a great impact on seed potato production. Numerous PVY strain groups with different pathogenicity and economical impact are distributed worldwide. Tools for accurate and reliable detection and discrimination of PVY strain groups are therefore essential for successful disease management. Two state of the art characterization tools based on detecting molecular markers RT-qPCR (Kogovsek et al., 2008) and SNaPshot (Rolland et al., 2008) were assessed for their ability to assign PVY accurately to the correct group. The results were validated by bioassay, ELISA and in silica sequence analysis. The spectrum of PVY strain groups distinguished by SNaPshot is broader than that by RT-qPCR. However, the latter was more reliable in discriminating the PVYNTN group members, known for their ability to induce PTNRD on selected potato cultivars. The difference in discrimination precision was due to different molecular markers being targeted by RT-qPCR and SNaPshot. Both tools use genotypic markers for detecting PVYNTN strain groups. Future development, however, should be focused on identifying the genomic determinants of the tuber necrosis property. Until then, the RT-qPCR and SNaPshot methods remain the most powerful diagnostic tools for detecting the PVY subgroup isolates found in Europe. (C) 2013 Elsevier B.V. All rights reserved