ORCID Profile
0000-0002-1534-4995
Current Organisation
The University of Auckland
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Publisher: Oxford University Press (OUP)
Date: 16-08-2017
Publisher: Springer Science and Business Media LLC
Date: 16-06-2016
DOI: 10.1038/NCOMMS11870
Abstract: Sponges (phylum Porifera) are early- erging metazoa renowned for establishing complex microbial symbioses. Here we present a global Porifera microbiome survey, set out to establish the ecological and evolutionary drivers of these host–microbe interactions. We show that sponges are a reservoir of exceptional microbial ersity and major contributors to the total microbial ersity of the world’s oceans. Little commonality in species composition or structure is evident across the phylum, although symbiont communities are characterized by specialists and generalists rather than opportunists. Core sponge microbiomes are stable and characterized by generalist symbionts exhibiting amensal and/or commensal interactions. Symbionts that are phylogenetically unique to sponges do not disproportionally contribute to the core microbiome, and host phylogeny impacts complexity rather than composition of the symbiont community. Our findings support a model of independent assembly and evolution in symbiont communities across the entire host phylum, with convergent forces resulting in analogous community organization and interactions.
Publisher: Wiley
Date: 13-10-2017
Abstract: Marine sponges host stable and species-specific microbial symbionts that are thought to be acquired and maintained by the host through a combination of vertical transmission and filtration from the surrounding seawater. To assess whether the microbial symbionts also actively contribute to the establishment of these symbioses, we performed in situ experiments on Orpheus Island, Great Barrier Reef, to quantify the chemotactic responses of natural populations of seawater microorganisms towards cellular extracts of the reef sponge Rhopaloeides odorabile. Flow cytometry analysis revealed significant levels of microbial chemotaxis towards R. odorabile extracts and 16S rRNA gene licon sequencing showed enrichment of 'sponge-specific' microbial phylotypes, including a cluster within the Gemmatimonadetes and another within the Actinobacteria. These findings infer a potential mechanism for how sponges can acquire bacterial symbionts from the surrounding environment and suggest an active role of the symbionts in finding their host.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.IJPORL.2018.07.024
Abstract: Culture-independent methods, based on bacterial 16 S rRNA gene sequencing, have been used previously to investigate the adenotonsillar microbiota. However, these studies have focused on a single s ling site (usually a surface swab). We aimed to investigate potential differences in adenotonsillar microbiota according to s ling location, both on and within the adenoids and palatine tonsils. Pediatric patients (n = 28, mean age five years) undergoing adenotonsillectomy were recruited for this study. At the time of surgery, a mucosal adenoid surface swab and an adenoid tissue biopsy was collected. Immediately following surgery, the crypts of the right and left tonsils were swabbed, and a surface and core tissue s le from the right tonsil were also collected. Bacterial 16 S rRNA gene-targeted licon sequencing was used to determine the bacterial composition of the collected s les. There was no significant difference in ersity or composition of the adenoid microbiota based on s ling site. However, the Shannon-Wiener and Inverse-Simpson ersity indices differed significantly (p < 0.05) between the microbial communities of the three different tonsil s ling sites. There was a higher average relative abundance of members from the genera Streptococcus, Actinobacillus, and Neisseria in the tonsil crypts when compared with surface and core tonsil tissue s les. Our results indicate that there is variation in bacterial ersity and composition based on s ling sites in the tonsils but not the adenoids. The difference in microbiota between the surface and the tissue may have implications for our understanding of the pathogenesis of recurrent tonsillitis and have treatment implications.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.IJPORL.2018.12.030
Abstract: Adenotonsillar and middle ear diseases result in some of the most frequently performed operations in the pediatric population worldwide. The pathogen reservoir hypothesis (PRH) suggests that the adenoids act as a reservoir of bacteria which play a potential pathogenic role in otitis media. Evidence supporting this hypothesis is limited. This study sought to comprehensively determine and compare associations between the adenotonsillar and middle ear bacterial microbiota within in idual patients via next-generation sequencing and microbial network analyses. Bacterial 16S rRNA gene-targeted licon sequencing was used to determine the bacterial composition of ten pediatric patients undergoing adenotonsillectomy and ventilation tube insertion for otitis media with effusion. At the time of surgery, swabs were taken from the adenoid surface, tonsil crypts and middle ear clefts (through the myringotomy incision). The most abundant sequences within the bacterial community at genus level across all anatomical sites were Fusobacterium, Haemophilus, Neisseria, and Porphyromonas. There was an observable difference in the relative abundance of bacterial communities, with a higher proportion of Haemophilus and Moraxella in the adenoid when compared with the middle ear. Furthermore, only one module (consisting of 4 bacterial OTUs) from one patient was identified through microbial network analyses to be significantly associated between middle ear and adenoid. In addition, microbial network analysis revealed that the adenoid and tonsil microbiota share greater similarity than do the adenoid and middle ear. The results of this study suggest that the adenoid microenvironment does not correlate to the middle ear microenvironment. A future study at the species level, and over time, is required to further investigate whether the differing relationship between the microbiota of the adenoid and middle ear rejects the pathogen reservoir hypothesis.
Publisher: Wiley
Date: 10-02-2017
Abstract: The study of complex microbial communities poses unique conceptual and analytical challenges, with microbial species potentially numbering in the thousands. With transient or allochthonous microorganisms often adding to this complexity, a 'core' microbiota approach, focusing only on the stable and permanent members of the community, is becoming increasingly popular. Given the various ways of defining a core microbiota, it is prudent to examine whether the definition of the core impacts upon the results obtained. Here we used complex marine sponge microbiotas and undertook a systematic evaluation of the degree to which different factors used to define the core influenced the conclusions. Significant differences in alpha- and beta- ersity were detected using some but not all core definitions. However, findings related to host specificity and environmental quality were largely insensitive to major changes in the core microbiota definition. Furthermore, none of the applied definitions altered our perception of the ecological networks summarising interactions among bacteria within the sponges. These results suggest that, while care should still be taken in interpretation, the core microbiota approach is surprisingly robust, at least for comparing microbiotas of closely related s les.
Publisher: Wiley
Date: 09-2020
Publisher: Wiley
Date: 17-03-2021
Abstract: Invasive alien species can cause detrimental changes in native ecosystems, but our understanding of the interactions between multiple exotic species is limited. To evaluate the joint effect of multiple sympatric invaders on an ecosystem, we must first understand how they interact with each other. Here, we quantified the spatial distribution, dietary composition and overlap of four invasive generalist vespid species (two Vespula and two Polistes ) that co‐occur on Ahuahu off the north‐east coast of New Zealand. We used DNA metabarcoding of larval faecal material to identify prey species, and mapped the locations of nests. We observed clear spatial partitioning, with different wasp species aggregating in different habitats. Diet differed both among wasp species (diet partitioning) and among seasons (temporal partitioning). There was stronger competition (highest diet overlap) between Vespula germanica and Vespula vulgaris than between other wasp species, but partitioning resources minimised spatial and diet overlap between the four species. Additionally, we obtained high‐resolution diet inventories that help assess the combined ecological impact of invasion by multiple wasps. These species consumed mostly native and endemic invertebrates from multiple trophic levels, but particularly herbivores (Lepidoptera). We provide direct evidence that in combination they exploited a wide range of endemic invertebrates. Synthesis and applications . Our study demonstrates resource partitioning among four invasive wasps, facilitating coexistence of these generalist invaders. We conclude that coexistence probably lifies their ecological impact. Quantifying how multiple invaders exploit and partition resources provides insights into how communities assemble and helps to assess the cumulative effects of multiple invaders on the recipient community.
Publisher: Wiley
Date: 21-11-2017
Abstract: Many marine sponges contain dense and erse communities of associated microorganisms. Members of the 'sponge-associated unclassified lineage' (SAUL) are frequently recorded from sponges, yet little is known about these bacteria. Here we investigated the distribution and phylogenetic status of SAUL. A meta-analysis of the available literature revealed the widespread distribution of this clade and its association with taxonomically varied sponge hosts. Phylogenetic analyses, conducted using both 16S rRNA gene-based phylogeny and concatenated marker protein sequences, revealed that SAUL is a sister clade of the candidate phylum 'Latescibacteria'. Furthermore, we conducted a comprehensive analysis of two draft genomes assembled from sponge metagenomes, revealing novel insights into the physiology of this symbiont. Metabolic reconstruction suggested that SAUL members are aerobic bacteria with facultative anaerobic metabolism, with the capacity to degrade multiple sponge- and algae-derived carbohydrates. We described for the first time in a sponge symbiont the putative genomic capacity to transport phosphate into the cell and to produce and store polyphosphate granules, presumably constituting a phosphate reservoir for the sponge host in deprivation periods. Our findings suggest that the lifestyle of SAUL is symbiotic with the host sponge, and identify symbiont factors which may facilitate the establishment and maintenance of this relationship.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.IJPORL.2018.07.041
Abstract: Obstructive sleep apnea (OSA) is now a more common indication for tonsillectomy than recurrent tonsillitis (RT) [1,2]. Few studies have addressed possible differences in pathogenesis between these two conditions. Children with RT and OSA are often being treated in the community with multiple courses of antibiotics before surgery. Current understanding of the role of bacteria in disorders of the tonsils is mainly based on the culture of tonsil swabs. Swab cultures reflect only a very small fraction of the bacteria present on the mucosal surface and may not represent the bacterial communities within the tonsil crypts [3,4]. This study aimed to evaluate the local lymphocyte response and associations with bacterial community composition using molecular techniques of the tonsils removed from children for RT or OSA. The palatine tonsils were removed by extracapsular dissection from 24 patients with age range one to ten years, 14 of whom had RT and 10 had OSA. The fixed tonsil tissues were evaluated for bacteria by Gram-staining and presence of connective tissue by safranin staining. B lymphocytes and T lymphocytes were also measured immunohistochemically. Finally, previously published bacterial community data for this cohort were reassessed for associations with RT and OSA, and with the observed lymphocyte patterns. In tonsils from patients with RT, large micro-colonies of bacteria were observed in the tonsil crypts, and a large number of B and T lymphocytes were noted immediately adjacent to the tonsil crypt itself. In marked contrast, the tonsils from patients with OSA had no bacteria identified, and no significant skewing of lymphocytes based on site (such as follicles or crypts). We observed that the majority of lymphocytes surrounding the bacterial micro-colonies were B lymphocytes with a mean ratio of 109:55 (B lymphocytes: T lymphocytes). Bacterial community ersity was not different between the two cohorts however, there were significant differences in bacterial community composition. Children with RT had a higher relative abundance of members from the genera Parvimonas, Prevotella, and Treponema. While children with OSA had a higher relative abundance of Haemophilus, and Capnocytophaga. These results demonstrate significant differences in the local lymphocyte response and bacterial community composition in tonsil tissue between RT and OSA patients. It suggests that the response to antibiotics used in the treatment of these two conditions may be different. Furthermore, the presence of lymphocytes in RT within the tonsil crypt outside the tonsil epithelium is a unique observation of the location of these cells.
No related grants have been discovered for Maria del Carmen Astudillo Garcia.