The potato cyst nematode, Globodera rostochiensis, is an important pest of potato. Like other pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm, to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative G. rostochiensis putative apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Several CLAVATA3/ESR-like proteins induced developmental phenotypes, whereas predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. When directed to the apoplast with a signal peptide, two effectors, an ubiquitin extension protein (GrUBCEP12) and an expansin-like protein (GrEXPB2), suppressed defense responses including NB-LRR signaling induced in the cytoplasm. GrEXPB2 also elicited defense response in species- and sequence-specific manner. Our results are consistent with the scenario whereby potato cyst nematodes secrete effectors that modulate host cell fate and metabolism as well as modifying host cell walls. Furthermore, we show a novel role for an apoplastic expansin-like protein in suppressing intra-cellular defense responses.
Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense responses in N. tabacum, which was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.
Although community services support ageing-in-place, older adults often report feelings of loneliness and social isolation. Unmet emotional needs are associated with poorer health, reduced functional abilities and increased mortality in this population. Pet ownership is an avenue worth exploring to reduce these adverse outcomes. This scoping review maps main findings and identifies key gaps with respect to the pros and cons of pet ownership in community-dwelling older adults pertaining to psycho-social, physical and functional outcomes. Scientific and grey literature published from January 2000 to July 2018 was searched. Data selection and extraction were performed by the first author and a sub-sample was co-validated by two co-authors. A total of 62 sources were included for descriptive and thematic analysis. A variety of pros (increased physical activity, wellbeing) and cons (grief, risk of falls) pertaining to psycho-social and physical outcomes were identified. Not many functional outcomes (support for daily routines) were mentioned, and few studies explored the simultaneous balance between the pros and cons of pet care. Further research exploring both clinicians’ and older pet owners’ perspectives is needed to deepen our understanding of the importance of considering companion animals in older adults’ daily lives and to strike a balance between perceived risks and benefits.
Objective Wellness is a challenge for Indigenous peoples, partly because Western services do not adopt a holistic approach. By devaluing traditional knowledge, Indigenous values and beliefs, these services lower Indigenous power and affect cultural identities. Indigenous elders participate in intergenerational solidarity by transmitting knowledge, values, and culture in a holistic approach. Despite widespread acceptance of the importance of Indigenous elders' contributions to wellness, a rigorous synthesis of knowledge has never been done. This study aimed to provide a comprehensive understanding of how Indigenous elders' social participation contributes to individual and community wellness. Method A scoping review was conducted with Indigenous elders and stakeholders in Québec (Canada). Sixteen databases were searched with 57 keywords. Data from the documents retrieved were analyzed, organized, and synthesized based on the International Classification of Functioning, Disability and Health. Synthesis A total of 144 documents were examined, comprising 74 scientific papers and 70 sources from the gray literature. Indigenous elders contributed to wellness mainly through relationships and interactions with other community members and non-Indigenous people (72.2%); intergenerational oral and written communications (70.1%); community, social and civic life (45.8%); volunteering and jobs (35.4%); and family life (29.9%). Elders transmit traditional knowledge, strengthen social cohesion, and help to develop positive attitudes such as reciprocity. Their actions favour disease prevention and health promotion, as including traditional approaches increases the acceptability of health and social services. Conclusion This scoping review highlights the need for longitudinal studies with mixed-method designs involving Indigenous communities at all stages of the research to deepen understanding of the contributions of Indigenous elders to individual and community wellness.
Staphylococcus aureus is a leading cause of bovine intramammary infections (IMIs) that can evolve into difficult-to-treat chronic mastitis. To date, no vaccine formulation has shown high protective efficacy against S. aureus IMI, partly because this bacterium can efficiently evade the immune system. For instance, S. aureus small colony variants (SCVs) have intracellular abilities and can persist without producing invasive infections. As a first step towards the development of a live vaccine, this study describes the elaboration of a novel attenuated mutant of S. aureus taking advantage of the SCV phenotype. A genetically stable SCV was created through the deletion of the hemB gene, impairing its ability to adapt and revert to the invasive phenotype. Further attenuation was obtained through inactivation of gene vraG (SACOL0720) which we previously showed to be important for full virulence during bovine IMIs. After infection of bovine mammary epithelial cells (MAC-T), the double mutant (ΔvraGΔhemB) was less internalized and caused less cell destruction than that seen with ΔhemB and ΔvraG, respectively. In a murine IMI model, the ΔvraGΔhemB mutant was strongly attenuated, with a reduction of viable counts of up to 5-log10 CFU/g of mammary gland when compared to the parental strain. A complete clearance of ΔvraGΔhemB from glands was observed whereas mortality rapidly (48h) occurred with the wild-type strain. Immunization of mice using subcutaneous injections of live ΔvraGΔhemB raised a strong immune response as judged by the high total IgG titers measured against bacterial cell extracts and by the high IgG2a/IgG1 ratio observed against the IsdH protein. Also, ΔvraGΔhemB had sufficient common features with bovine mastitis strains so that the antibody response also strongly recognized strains from a variety of mastitis associated spa types. This double mutant could serve as a live-attenuated component in vaccines to improve cell-mediated immune responses against S. aureus IMIs.
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