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"Anthony, Colin"
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Rapid, high-throughput phenotypic profiling of endosymbiotic dinoflagellates (Symbiodiniaceae) using benchtop flow cytometry
Endosymbiotic dinoflagellates (Family Symbiodiniaceae) are the primary producer of energy for many cnidarians, including corals. The intricate coral-dinoflagellate symbiotic relationship is becoming increasingly important under climate change, as its breakdown leads to mass coral bleaching and often mortality. Despite methodological progress, assessing the phenotypic traits of Symbiodiniaceae in-hospite remains a complex task. Bio-optics, biochemistry, or “-omics” techniques are expensive, often inaccessible to investigators, or lack the resolution required to understand single-cell phenotypic states within endosymbiotic dinoflagellate assemblages. To help address this issue, we developed a protocol that collects information on cell autofluorescence, shape, and size to simultaneously generate phenotypic profiles for thousands of Symbiodiniaceae cells, thus revealing phenotypic variance of the Symbiodiniaceae assemblage to the resolution of single cells. As flow cytometry is adopted as a robust and efficient method for cell counting, integration of our protocol into existing workflows allows researchers to acquire a new level of resolution for studies examining the acclimation and adaptation strategies of Symbiodiniaceae assemblages.
Journal Article
Phenotypic plasticity in Cassiopea ornata (Cnidaria: Scyphozoa: Rhizostomeae) suggests environmentally driven morphology
This contribution investigates phenotypic plasticity in
Cassiopea ornata
Haeckel, 1880 from Guam, Micronesia. We collected
C. ornata
from two distinct habitats and used DNA barcoding for species identification. With this, we were able to document intraspecific phenotypic variation between populations that is likely reflective of distinct ecotypes rather than species-specific disparities. In particular, macromorphological characters, such as vesicle shapes and sizes, have been used as characters to discriminate among species of
Cassiopea
varied between populations. In addition, we uncovered differences in cassiosome structure and composition between populations that suggest differences in trophic modes across populations. Conducting a meta-analysis of a comprehensive cnidome dataset, we show that nematocysts may provide important information for species delineation and identification in
Cassiopea
, a suite of characters not fully exploited thus far. We interpret differences in vesicle and cassiosome morphology in conjunction with nematocyst size disparities as a reflection of environment-mediated shifts in trophic strategy (photo-autotrophy
versus
heterotrophy). Given the interest in
Cassiopea
as a model organism, the observations presented herein lay out a roadmap for studies that aim at linking environmental heterogeneity to phenotypic plasticity.
Journal Article
ADCC-mediating non-neutralizing antibodies can exert immune pressure in early HIV-1 infection
Despite antibody-dependent cellular cytotoxicity (ADCC) responses being implicated in protection from HIV-1 infection, there is limited evidence that they control virus replication. The high mutability of HIV-1 enables the virus to rapidly adapt, and thus evidence of viral escape is a very sensitive approach to demonstrate the importance of this response. To enable us to deconvolute ADCC escape from neutralizing antibody (nAb) escape, we identified individuals soon after infection with detectable ADCC responses, but no nAb responses. We evaluated the kinetics of ADCC and nAb responses, and viral escape, in five recently HIV-1-infected individuals. In one individual we detected viruses that escaped from ADCC responses but were sensitive to nAbs. In the remaining four participants, we did not find evidence of viral evolution exclusively associated with ADCC-mediating non-neutralizing Abs (nnAbs). However, in all individuals escape from nAbs was rapid, occurred at very low titers, and in three of five cases we found evidence of viral escape before detectable nAb responses. These data show that ADCC-mediating nnAbs can drive immune escape in early infection, but that nAbs were far more effective. This suggests that if ADCC responses have a protective role, their impact is limited after systemic virus dissemination.
Journal Article
An Integrated Safety, Health and Environmental Management Capability Maturity Model for Construction Organisations: A Case Study in Ghana
Safety, health and environmental (SHE) management is becoming a priority as construction companies (i.e., contractors) strive to reduce construction accidents and negative environmental impacts, conform to regulatory requirements, and sustain their competitiveness. Consequently, construction firms are expected to adopt and implement innovative SHE management systems to mitigate SHE risks effectively and efficiently. For construction firms to effectively do this, they need to have the adequate capability in respect of integrated SHE management. However, there is limited empirical insight regarding the integrated SHE management capabilities of construction companies. Furthermore, there is limited insight regarding the mechanisms for ascertaining the integrated SHE management capability of construction companies to guide such organisations towards SHE management excellence in their operations. Drawing on the capability maturity model integration (CMMI) concept, this study, by applying expert reviews (i.e., Delphi technique and the design methodology for capability maturity grids), developed an integrated Safety, Health and Environmental Management Maturity Model (iSHEM-CMM). The model offers capability maturity assessment on a five-level scale within five thematic categories and 20 integrated SHE management capability attributes. Based on an industrial validation by construction professionals, it is concluded that the maturity model is a useful assessment framework or tool for industry stakeholders, particularly construction firms, to evaluate the status of their current SHE management capabilities, identify strengths and improvement areas, and accordingly prioritise strategies/actions for improving their SHE management. Furthermore, clients who appoint construction companies could use the model as part of prequalification arrangements in selecting construction companies with an adequate SHE management capability.
Journal Article
Molecular characterization of chikungunya virus during the 2019 outbreak in the Democratic Republic of the Congo
Early 2019, a chikungunya virus (CHIKV) outbreak hit the Democratic Republic of the Congo (DRC). Though seldomly deadly, this mosquito-borne disease presents as an acute febrile (poly)arthralgia often followed by long-term sequelae. Although Aedes aegypti is the primary vector, an amino acid substitution in the viral envelope gene E1 (A226V) is causing concern as it results in increased transmission by Aedes albopictus, a mosquito with a much wider geographical distribution. Between January and March 2019, we collected human and mosquito samples in Kinshasa and Kongo Central province (Kasangulu and Matadi). Of the patients that were tested within 7 days of symptom onset, 49.7% (87/175) were RT-qPCR positive, while in the mosquito samples CHIKV was found in 1/2 pools in Kinshasa, 5/6 pools in Kasangulu, and 8/26 pools in Matadi. Phylogenetic analysis on whole-genome sequences showed that the circulating strain formed a monophyletic group within the ECSA2 lineage and harboured the A226V mutation. Our sequences did not cluster with sequences from previously reported outbreaks in the DRC nor with other known A226V-containing ECSA2 strains. This indicates a scenario of convergent evolution where A226V was acquired independently in response to a similar selection pressure for transmission by Ae. albopictus. This is in line with our entomological data where we detected Ae. albopictus more frequently than Ae. aegypti in two out of three affected areas. In conclusion, our findings suggest that CHIKV is adapting to the increased presence of Aedes albopictus in DRC.
Journal Article
Rapid, high-throughput phenotypic profiling of endosymbiotic dinoflagellates
Endosymbiotic dinoflagellates (Family Symbiodiniaceae) are the primary producer of energy for many cnidarians, including corals. The intricate coral-dinoflagellate symbiotic relationship is becoming increasingly important under climate change, as its breakdown leads to mass coral bleaching and often mortality. Despite methodological progress, assessing the phenotypic traits of Symbiodiniaceae in-hospite remains a complex task. Bio-optics, biochemistry, or \"-omics\" techniques are expensive, often inaccessible to investigators, or lack the resolution required to understand single-cell phenotypic states within endosymbiotic dinoflagellate assemblages. To help address this issue, we developed a protocol that collects information on cell autofluorescence, shape, and size to simultaneously generate phenotypic profiles for thousands of Symbiodiniaceae cells, thus revealing phenotypic variance of the Symbiodiniaceae assemblage to the resolution of single cells. As flow cytometry is adopted as a robust and efficient method for cell counting, integration of our protocol into existing workflows allows researchers to acquire a new level of resolution for studies examining the acclimation and adaptation strategies of Symbiodiniaceae assemblages.
Journal Article
Viral variants that initiate and drive maturation of V1V2-directed HIV-1 broadly neutralizing antibodies
Penny Moore and colleagues identify viral variants from an HIV-1 infected individual that drove maturation of the antibody response from an unmutated common ancestor, ultimately resulting in both broadly neutralizing and strain-specific antibody sublineages.
The elicitation of broadly neutralizing antibodies (bNAbs) is likely to be essential for a preventative HIV-1 vaccine, but this has not yet been achieved by immunization. In contrast, some HIV-1-infected individuals naturally mount bNAb responses during chronic infection, suggesting that years of maturation may be required for neutralization breadth
1
,
2
,
3
,
4
,
5
,
6
. Recent studies have shown that viral diversification precedes the emergence of bNAbs, but the significance of this observation is unknown
7
,
8
. Here we delineate the key viral events that drove neutralization breadth within the CAP256-VRC26 family of 33 monoclonal antibodies (mAbs) isolated from a superinfected individual. First, we identified minority viral variants, termed bNAb-initiating envelopes, that were distinct from both of the transmitted/founder (T/F) viruses and that efficiently engaged the bNAb precursor. Second, deep sequencing revealed a pool of diverse epitope variants (immunotypes) that were preferentially neutralized by broader members of the antibody lineage. In contrast, a 'dead-end' antibody sublineage unable to neutralize these immunotypes showed limited evolution and failed to develop breadth. Thus, early viral escape at key antibody-virus contact sites selects for antibody sublineages that can tolerate these changes, thereby providing a mechanism for the generation of neutralization breadth within a developing antibody lineage.
Journal Article
The financial returns from buying versus renting
PurposeThe UK experienced a substantial rise in owner occupation over the twentieth century, and many tenants still aspire to homeownership. These strong aspirations to own are attributed to a set of financial and non-financial benefits. This paper aims to calculate, for the first time, the financial returns from buying versus renting in Britain for first-time buyers in 11 regions.Design/methodology/approachIt applies a DCF approach based on historical housing and mortgage market data from 1975 to 2012.FindingsThe paper finds strong evidence that, in purely financial terms, buying has been always superior to renting in all regions of the UK over the period.Practical implicationsIt gives a clear message of the financial benefits of homeownership over renting in Britain, even over very short time periods.Originality/valueThe paper is the first to apply a comprehensive DCF model to the choice between renting and owning.
Journal Article