13 research outputs found
Important marine areas for the conservation of northern rockhopper penguins within the Tristan da Cunha Exclusive Economic Zone
The designation of Marine Protected Areas has become an important approach to conserving marine ecosystems that relies on robust information on the spatial distribution of biodiversity. We used GPS tracking data to identify marine Important Bird and Biodiversity Areas (IBAs) for the endangered northern rockhopper penguin Eudyptes moseleyi within the Exclusive Economic Zone (EEZ) of Tristan da Cunha in the South Atlantic. Penguins were tracked throughout their breeding season from 3 of the 4 main islands in the Tristan da Cunha group. Foraging trips remained largely within the EEZ, with the exception of those from Gough Island during the incubation stage. We found substantial variability in trip duration and foraging range among breeding stages and islands, consistent use of areas among years and spatial segregation of the areas used by neighbouring islands. For colonies with no or insufficient tracking data, we defined marine IBAs based on the mean maximum foraging range and merged the areas identified to propose IBAs around the Tristan da Cunha archipelago and Gough Island. The 2 proposed marine IBAs encompass 2% of Tristan da Cunha’s EEZ, and are used by all northern rockhopper penguins breeding in the Tristan da Cunha group, representing ~90% of the global population. Currently, the main threat to northern rockhopper penguins within the Tristan da Cunha EEZ is marine pollution from shipping, and the risk of this would be reduced by declaring waters within 50 nautical miles of the coast as ‘Areas To Be Avoided
SARS-CoV-2 Beta and Delta variants trigger Fc effector function with increased cross-reactivity
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern (VOCs) exhibit escape
from neutralizing antibodies, causing concern about vaccine effectiveness. However, while non-neutralizing
cytotoxic functions of antibodies are associated with improved disease outcome and vaccine protection, Fc
effector function escape from VOCs is poorly defined. Furthermore, whether VOCs trigger Fc functions with
altered specificity, as has been reported for neutralization, is unknown. Here, we demonstrate that the Beta
VOC partially evades Fc effector activity in individuals infected with the original (D614G) variant. However, not
all functions are equivalently affected, suggesting differential targeting by antibodies mediating distinct Fc
functions. Furthermore, Beta and Delta infection trigger responses with significantly improved Fc cross-reactivity
against global VOCs compared with D614G-infected or Ad26.COV2.S-vaccinated individuals. This suggests
that, as for neutralization, the infecting spike sequence affects Fc effector function. These data have
important implications for vaccine strategies that incorporate VOCs, suggesting these may induce broader
Fc effector responses.The EDCTP2 program of the European Union’s Horizon 2020 program, Wellcome Centre for Infectious Diseases Research in Africa, the SA-MRC, MRC UK, NRF, the Lily and Ernst Hausmann Trust, the South African Research Chairs Initiative of the Department of Science and Innovation and National Research Foundation of South Africa, the SA Medical Research Council SHIP program, the Center for the AIDS Program of Research (CAPRISA) and an L’Oreal/UNESCO Women in Science South Africa Young Talents award.http://www.cell.com/cell-host-microbe/homeam2023ImmunologyInternal Medicin
Shared N417-dependent epitope on the SARS-CoV-2 Omicron, Beta, and Delta Plus variants
As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, several variants of concern (VOCs) have arisen which are defined by multiple mutations in their spike proteins. These VOCs have shown variable escape from antibody responses and have been shown to trigger qualitatively different antibody responses during infection. By studying plasma from individuals infected with either the original D614G, Beta, or Delta variants, we showed that the Beta and Delta variants elicit antibody responses that are overall more cross-reactive than those triggered by D614G. Patterns of cross-reactivity varied, and the Beta and Delta variants did not elicit cross-reactive responses to each other. However, Beta-elicited plasma was highly cross-reactive against Delta Plus (Delta+), which differs from Delta by a single K417N mutation in the receptor binding domain, suggesting that the plasma response targets the N417 residue. To probe this further, we isolated monoclonal antibodies from a Beta-infected individual with plasma responses against Beta, Delta+, and Omicron, which all possess the N417 residue. We isolated an N417-dependent antibody, 084-7D, which showed similar neutralization breadth to the plasma. The 084-7D MAb utilized the IGHV3-23*01 germ line gene and had somatic hypermutations similar to those of previously described public antibodies which target the 417 residue. Thus, we have identified a novel antibody which targets a shared epitope found on three distinct VOCs, enabling their cross-neutralization. Understanding antibodies targeting escape mutations, such as K417N, which repeatedly emerge through convergent evolution in SARS-CoV-2 variants, may aid in the development of next-generation antibody therapeutics and vaccines.
IMPORTANCE : The evolution of SARS-CoV-2 has resulted in variants of concern (VOCs) with distinct spike mutations conferring various immune escape profiles. These variable mutations also influence the cross-reactivity of the antibody response mounted by individuals infected with each of these variants. This study sought to understand the antibody responses elicited by different SARS-CoV-2 variants and to define shared epitopes. We show that Beta and Delta infections resulted in antibody responses that were more cross-reactive than the original D614G variant, but they had differing patterns of cross-reactivity. We further isolated an antibody from Beta infection which targeted the N417 site, enabling cross-neutralization of Beta, Delta+, and Omicron, all of which possess this residue. The discovery of antibodies which target escape mutations common to multiple variants highlights conserved epitopes to target in future vaccines and therapeutics.The South African Research Chairs Initiative of the Department of Science and Innovation, the National Research Foundation of South Africa, the SA Medical Research Council SHIP program and the Bill and Melinda Gates Foundation, through the Global Immunology and Immune Sequencing for Epidemic Response (GIISER) program.https://journals.asm.org/journal/jvihj2023ImmunologyInternal Medicin
Ad26.COV2.S breakthrough infections induce high titers of neutralizing antibodies against Omicron and other SARS-CoV-2 variants of concern
The Janssen (Johnson & Johnson) Ad26.COV2.S non-replicating viral vector vaccine has been widely
deployed for COVID-19 vaccination programs in resource-limited settings. Here we confirm that neutralizing
and binding antibody responses to Ad26.COV2.S vaccination are stable for 6 months post-vaccination, when
tested against multiple SARS-CoV-2 variants. Secondly, using longitudinal samples from individuals who
experienced clinically mild breakthrough infections 4 to 5 months after vaccination, we show dramatically
boosted binding antibodies, Fc effector function, and neutralization. These high titer responses are of similar
magnitude to humoral immune responses measured in convalescent donors who had been hospitalized with
severe illness, and are cross-reactive against diverse SARS-CoV-2 variants, including the neutralizationresistant
Omicron (B.1.1.529) variant that currently dominates global infections, as well as SARS-CoV-1.
These data have implications for population immunity in areas where the Ad26.COV2.S vaccine has been
widely deployed, but where ongoing infections continue to occur at high levels.The South African Medical Research Council, the South African Research Chairs Initiative of the Department of Science and Innovation; the National Research Foundation of South Africa, the EDCTP2 program of the European Union’s Horizon 2020 program, the Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), which is supported by core funding from the Wellcome Trust and the Poliomyelitis Research Foundation, MRC UK, NRF, the Lily and Ernst Hausmann Trust and L’Oreal/Unesco Women in Science South Africa Young Talents awardee.http://www.cell.com/cell-host-microbe/homeImmunologyInternal Medicin
Recent population trends of sooty and light-mantled albatrosses breeding on Marion Island
Sub-Antarctic Marion Island is one of the few islands where both species of Phoebetria albatrosses breed sympatrically. The last published assessment of their population trends, which reported counts up to 2008, concluded that the numbers of breeding pairs of sooty albatross P. fusca (Endangered) were decreasing, whereas numbers of light-mantled albatross P. palpebrata (Near Threatened) were increasing. Extending the counts to 2014 reversed these trends, with numbers of sooty albatrosses increasing from 2006 to 2014, and numbers of light-mantled albatrosses decreasing from 2007 to 2014. Confidence in island-wide counts is low due to the cryptic nature of the albatrosses on their largely inaccessible cliff-side nest sites, as well as counts for sooty albatrosses taking place late in the incubation period when 10−20% of nests have already failed. Given the greater conservation concern for the sooty albatross, we recommend that dedicated annual counts be conducted during the early incubation period, and be repeated shortly after the chicks hatch (late December), mid-way through the nestling period (late February) and prior to fledging (late April), to give a better idea of breeding success. Count zones also should be revised to facilitate more accurate counts, ensuring more reliable estimates of sooty albatross population trends at Marion Island.Keywords: count technique, phenology, Phoebetria, population size, Prince Edward Island
Pup growth and maternal attendance patterns in Subantarctic fur seals
Samples of pups from the expanding populations of Subantarctic fur seals (Arctocephalus tropicalis) at Marion and Gough islands were weighed at specific ages between birth and weaning in the period 1993-2000. Growth was estimated and compared between years, sexes, sites of different density, and populations. Pups of comparable age were consistently heavier at Marion Island than at Gough Island, probably reflecting relative prey resource abundance. No changes in pup growth rates were apparent over the study period, nor was there any evidence that growth was affected by ENSO events. Measures of pup growth at Marion Island were complemented by measures of maternal attendance behaviour during three summer and winter seasons. More years of data are required to determine patterns between attendance, growth, resource conditions and population abundance trends.Key words: Subantarctic fur seal, Marion Island, Gough Island, pup growth, maternal attendance behaviour
Long-term variation in the breeding diets of macaroni and eastern rockhopper penguins at Marion Island (1994–2018)
Populations of the macaroni penguin Eudyptes chrysolophus and the eastern rockhopper penguin E. filholi breeding at Marion Island (Prince Edward Islands) in the sub-Antarctic Indian Ocean decreased from 1994 to 2018. We examined their diets when rearing chicks during this period. There was substantial overlap in the diets of the two species, with crustaceans, dominated by the euphausiids Thysanoessa vicina and Euphausia vallentini, making up >80% of the diets by number and >60% by mass over the study period. The lanternfishes Krefftichthys anderssoni and Protomyctophum tenisoni were the most-commonly consumed fish in the diet of breeding macaroni penguins and dominated in their diet in three of the 25 years (1994, 1998 and 2014); they were also the most commonly consumed fish by eastern rockhopper penguins. Macaroni penguins consumed more of the amphipod crustacean Themisto gaudichaudii and the lanternfish Electrona carlsbergi as well as a greater diversity of and larger-sized fish than did eastern rockhopper penguins. The horsefish Zanclorhynchus spinifer was found in substantial amounts in the diet of eastern rockhopper penguins in 1996 and 1997. Despite annual variations in relative prey contributions to the diets, there were no significant long-term changes in the diet of either penguin species over the study period or when compared with an earlier assessment in 1982. We conclude that changes in the relative proportions of prey in the diets of these penguin species during breeding are unlikely to account for the recent declines in these penguin populations
Geographical and temporal variation in the diet of Bank Cormorants Phalacrocorax neglectus in South Africa
The Bank Cormorant Phalacrocorax neglectus is endemic to the Benguela upwelling ecosystem off southwest Africa and is classified as Endangered owing to a recent large reduction in its number. It is thought that food scarcity, including a decreased abundance of West Coast rock lobster Jasus lalandii, has been a major driver of the decrease, yet its diet in South Africa is poorly known. We collected 941 pellets regurgitated by Bank Cormorants, at 18 South African breeding colonies during 1975–1985, and 1 523 pellets at 17 colonies during 1995–2002. The species composition of the diet (% numbers) was significantly different between the two periods, with widespread decreases in proportions of rock lobster in the west and of octopus and cuttlefish Sepia spp. at most localities. These taxa were replaced in the diet by fish, including Gobiidae and Clinidae. The pelagic goby Sufflogobius bibarbatus, an important prey of Bank Cormorants in Namibia, was absent from pellets collected in 1975–1985 but common at northern localities from 1995–2002. Composition of the diet by frequency of occurrence was only determined for 1995–2002, when rock lobster was present in 67% of all samples collected, cuttlefish in 39%, and Clinidae in 32%. Data for 1975–1985 and 1995–2002 showed that carapace lengths of rock lobsters eaten by Bank Cormorants averaged 56 mm (range 22–82 mm) and 50 mm (range 22–75 mm), respectively, which compares to the minimum legal size of 75 mm for fisheries in South Africa. This energyrich prey item was an important constituent of the diet in the winter breeding period. Variation géographique et temporelle dans le régime alimentaire des cormorans des bancs Phalacrocorax neglectus en Afrique du SudLe Cormoran des bancs Phalacrocorax neglectus est endémique de l’écosystème d’upwelling de Benguela au sud-ouest de l’Afrique et est classé en danger d’extinction en raison d’une importante réduction récente de ses nombres. On pense que la pénurie de nourriture, y compris une diminution de l’abondance de la Langouste du Cap, Jasus lalandii, a été l’un des principaux facteurs de cette baisse, toutefois son régime alimentaire en Afrique du Sud est mal connu. Nous avons recueilli 941 pelotes régurgitées par des Cormorans des bancs dans 18 colonies de reproduction sud-africaines en 1975–1985 et 1 523 pelotes dans 17 colonies en 1995–2002. La composition en espèces du régime alimentaire (nombre de%) était significativement différente entre les deux périodes, avec des diminutions généralisées des proportions de langouste du Cap et de poulpes et seiches Sepia spp. dans la plupart des localités. Les poissons, notamment les Gobiidae et les Clinidae, ont remplacé ces taxons dans le régime alimentaire. Le gobie pélagique Sufflogobius bibarbatus, une proie importante des cormorans des bancs en Namibie, était absent des pelotes récoltées de 1975 à 1985, mais commun dans les localités du nord de 1995 à 2002. La composition du régime alimentaire selon la fréquence d’occurrence n’a été déterminée que pour 1995–2002, lorsque la langouste était présente dans 67% de tous les échantillons recueillis, la seiche dans 39% et les Clinidae dans 32%. Entre 1975–1985 et 1995–2002, les longueurs de carapace de langoustes consommées par les cormorans des bancs étaient en moyenne de 56 mm (extrêmes de 22 à 82 mm) et 50 mm (extrêmes de 22 à 75 mm), ce qui est comparable à la taille minimale légale de 75 mm. pour la pêche en Afrique du Sud. Cette proie riche en énergie était un élément important du régime alimentaire en période de reproduction hivernale.Keywords: conservation, diet, ecosystem change, Endangered species, Jasus lalandii, prey energy, prey size, regurgitated pellet
Haulout site selection by southern elephant seals at Marion Island
Using data from an ongoing mark–resight programme at Marion Island, we tested empirically whether southern elephant seals prefer certain terrestrial sites to others during the breeding, moulting and winter haulouts, and whether the pattern of site use is the same for different age and sex groups. Southern elephant seals preferred some sites, while discriminating against other sites, with different age and sex classes using different sites for certain haulout events. Wintering young animals did not show strong site selection. Some popular sites were used for all haulouts by all age and sex groups, and apparently have all the requirements of a good site for terrestrial haulout by southern elephant seals. Site selection becomes more apparent with age, suggesting the role of haulout experience in site selection.Key words: southern elephant seal, Mirounga leonina, Marion Island, age group, haulout, site selection
Errata: In the article ‘Haulout site selection by southern elephant seals at Marion Island’ that appeared in
ErrataIn the article ‘Haulout site selection by southern elephant seals at Marion Island’ that appeared in African Zoology 43(1):25–33 (April 2008), the institutional affiliations of the authors should have read:T.W. Mulaudzi1*, G.J.G. Hofmeyr1, M.N. Bester1, S.P. Kirkman1, P.A. Pistorius1,F.C. Jonker1, A.B. Makhado1, J.H. Owen2 & R.J. Grimbeek21. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, 0002 South Africa2. Department of Statistics, University of Pretoria, Pretoria, 0002 South Africa*Author for correspondence. Present address: National Zoological Gardens of South Africa, P.O. Box 754, Pretoria, 0002 South Africa.E-mail: [email protected]