Phytopathogenic microbes use secreted effector proteins to increase their virulence
. If these effectors or the results of their activity are detected by the plant cell, the plant will mount an ...immune response which applies evolutionary pressure by reducing growth and success of the pathogen. Bacterial effector proteins in the AvrRps4 family (AvrRps4, HopK1, and XopO) have commonly been used as tools to investigate plant immune components. At the same time, the
functions of this family of effectors have yet to be fully characterized. In this minireview we summarize current knowledge about the AvrRps4 effector family with emphasis on properties of the proteins themselves. We hypothesize that the HopK1 C-terminus and the AvrRps4 C-terminus, though unrelated in sequence and structure, are broadly related in functions that counteract plant defense responses.
Type-2 low asthma affects 30-50% of people with severe asthma and includes a phenotype characterized by sputum neutrophilia and resistance to corticosteroids. Airways inflammation in type-2 low ...asthma or COPD is potentially driven by persistent bacterial colonization of the lower airways by bacteria such as non-encapsulated
(NTHi). Although pathogenic in the lower airways, NTHi is a commensal of the upper airways. It is not known to what extent these strains can invade airway epithelial cells, persist intracellularly and activate epithelial cell production of proinflammatory cytokines, and how this differs between the upper and lower airways. We studied NTHi infection of primary human bronchial epithelial cells (PBECs), primary nasal epithelial cells (NECs) and epithelial cell lines from upper and lower airways. NTHi strains differed in propensity for intracellular and paracellular invasion. We found NTHi was internalized within PBECs at 6 h, but live intracellular infection did not persist at 24 h. Confocal microscopy and flow cytometry showed NTHi infected secretory, ciliated and basal PBECs. Infection of PBECs led to induction of CXCL8, interleukin (IL)-1β, IL-6 and TNF. The magnitude of cytokine induction was independent of the degree of intracellular invasion, either by differing strains or by cytochalasin D inhibition of endocytosis, with the exception of the inflammasome-induced mediator IL-1β. NTHi-induced activation of TLR2/4, NOD1/2 and NLR inflammasome pathways was significantly stronger in NECs than in PBECs. These data suggest that NTHi is internalized transiently by airway epithelial cells and has capacity to drive inflammation in airway epithelial cells.
Understanding an animal’s diet is a crucial component of conservation, but diet data are often labor intensive to collect and are frequently scarce. Atlantic Puffins ( Fratercula arctica ; hereafter ...Puffins) are vulnerable to global extinction and have declined in some parts of their UK and Irish range. Differences in population trajectories may relate to diet, but Puffin diet data are currently only collected at a handful of colonies. We explored whether citizen science could address this data gap by inviting visitors to Puffin colonies in 2017 to submit their photographs of Puffins carrying prey. In total, 602 people submitted 1402 images from 35 colonies. We identified the species group, size, and number of prey items in each bill load. Photograph quality was excellent, with 89% of birds in images providing useable diet information. In total 11,150 prey items were counted and measured from 1198 Puffins across 27 colonies. We demonstrated a lack of bias in the sample of photos provided by citizen scientists and described how Puffin chick diet varies in prey composition, prey length, number of prey per bill load, and load biomass over large spatial scales and throughout the breeding season. The diet of Puffin chicks from regions where severe declines have occurred, most notably Shetland, were characterized by a lower prey biomass, higher numbers of fish per load, and a high proportion of small, transparent sandeels consistently through the season. By contrast, in regions where Puffin populations are thought to be increasing, load biomass was high, the number of prey per load low, and larger non-transparent sandeels were the dominant prey, which persisted right through the breeding season. Results from our study show colonies and regions where birds may be expending more effort (collecting more prey items) for lesser returns (lower load biomass) and emphasize the value of collecting diet data across large spatial scales.
Air-liquid interface (ALI) culture of nasal epithelial cells is a valuable tool in the diagnosis and research of primary ciliary dyskinesia (PCD). Ex vivo samples often display secondary dyskinesia ...from cell damage during sampling, infection or inflammation confounding PCD diagnostic results. ALI culture enables regeneration of healthy cilia facilitating differentiation of primary from secondary ciliary dyskinesia. We describe a revised ALI culture method adopted from April 2018 across three collaborating PCD diagnostic sites, including current University Hospital Southampton COVID-19 risk mitigation measures, and present results. Two hundred and forty nasal epithelial cell samples were seeded for ALI culture and 199 (82.9%) were ciliated. Fifty-four of 83 (63.9%) ex vivo samples which were originally equivocal or insufficient provided diagnostic information following in vitro culture. Surplus basal epithelial cells from 181 nasal brushing samples were frozen in liquid nitrogen; 39 samples were ALI-cultured after cryostorage and all ciliated. The ciliary beat patterns of ex vivo samples (by high-speed video microscopy) were recapitulated, scanning electron microscopy demonstrated excellent ciliation, and cilia could be immuno-fluorescently labelled (anti-alpha-tubulin and anti-RSPH4a) in representative cases that were ALI-cultured after cryostorage. In summary, our ALI culture protocol provides high ciliation rates across three centres, minimising patient recall for repeat brushing biopsies and improving diagnostic certainty. Cryostorage of surplus diagnostic samples was successful, facilitating PCD research.
The European Respiratory Society International Congress took place both in person, in Barcelona, Spain, and online in 2022. The congress welcomed over 19 000 attendees on this hybrid platform, ...bringing together exciting updates in respiratory science and medicine from around the world. In this article, Early Career Members of the Respiratory Infections Assembly (Assembly 10) summarise a selection of sessions across a broad range of topics, including presentations on bronchiectasis, nontuberculous mycobacteria, tuberculosis, cystic fibrosis and coronavirus disease 2019.
Air-liquid interface (ALI) cell culture of primary airway progenitors enables the differentiation and recapitulation of a pseudostratified epithelium
in vitro
, providing a highly useful tool for ...researching respiratory health and disease. Previous studies into gene expression in ALI-cultures compared to
ex vivo
nasal brushings have been limited in the number of time-points and/or the number of genes studied. In this study physiological and global transcriptomic changes were assessed in an extended
in vitro
63-day human healthy nasal epithelium ALI-culture period and compared to
ex vivo
nasal brushing samples.
Ex vivo
nasal brushing samples formed distinct transcriptome clusters to
in vitro
ALI-cultured nasal epithelia, with from day 14 onwards ALI samples best matching the
ex vivo
samples. Immune response regulation genes were not expressed in the
in vitro
ALI-culture compared to the
ex vivo
nasal brushing samples, likely because the
in vitro
cultures lack an airway microbiome, lack airborne particles stimulation, or did not host an immune cell component. This highlights the need for more advanced co-cultures with immune cell representation to better reflect the physiological state. During the first week of ALI-culture genes related to metabolism and proliferation were increased. By the end of week 1 epithelial cell barrier function plateaued and multiciliated cell differentiation started, although widespread ciliation was not complete until day 28. These results highlight that time-points at which ALI-cultures are harvested for research studies needs to be carefully considered to suit the purpose of investigation (transcriptomic and/or functional analysis).
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