Interspecific variations in the gastrointestinal microbiota in penguins

Despite the enormous amount of data available on the importance of the gastrointestinal (GI) microbiota in vertebrate (especially mammals), information on the GI microbiota of seabirds remains incomplete. As with many seabirds, penguins have a unique digestive physiology that enables them to store large reserves of adipose tissue, protein, and lipids. This study used quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA gene pyrosequencing to characterize the interspecific variations of the GI microbiota of four penguin species: the king, gentoo, macaroni, and little penguin. The qPCR results indicated that there were significant differences in the abundance of the major phyla Firmicutes, Bacteroides, Actinobacteria, and Proteobacteria. A total of 132,340, 18,336, 6324, and 4826 near full-length 16S rRNA gene sequences were amplified from fecal samples collected from king, gentoo, macaroni, and little penguins, respectively. A total of 13 phyla were identified with Firmicutes, Bacteroidetes, Proteobacteria, and Fusobacteria dominating the composition; however, there were major differences in the relative abundance of the phyla. In addition, this study documented the presence of known human pathogens, such as Campylobacter, Helicobacter, Prevotella, Veillonella, Erysipelotrichaceae, Neisseria, and Mycoplasma. However, their role in disease in penguins remains unknown. To our knowledge, this is the first study to provide an in-depth investigation of the GI microbiota of penguins.

Age-related differences revealed in Australian fur seal Arctocephalus pusillus doriferus gut microbiota

The gut microbiota of Australian fur seals (Arctocephalus pusillus doriferus) was examined at different age classes using fluorescent in situ hybridisation (FISH) and 16S rRNA gene pyrosequencing. The FISH results indicated that in the fur seal groups, the predominant phyla are Firmicutes (22.14-67.33%) followed by Bacteroidetes (3.11-15.45%) and then Actinobacteria (1.4-5.9%) consistent with other mammals. Phylum Proteobacteria had an initial abundance of 1.8% in the 2-month-old pups, but < 1% of bacterial numbers for the other fur seal age groups. Significant differences did occur in the abundance of Clostridia, Lactobacilli and Bifidobacteria between 2 months pups and 9 months pups and adult fur seals. Results from the 16S rRNA gene pyrosequencing supported the FISH data and identified significant differences in the composition of Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Verrucomicrobia and Fusobacteria at all ages. Class Clostridia in phylum Firmicutes dominates the microbiota of the 2 months and 9 months seal pups, whilst class Bacilli dominates the 6 months pups. In addition, a high level of dissimilarity was observed between all age classes. This study provides novel insight into the gut microbiota of Australian fur seals at different age classes.

Gastrointestinal microbiota of seabirds

This work provided novel insight into the previously uncharacterised microbial composition of Antarctic and temperate penguins and procellariiform seabirds. Using real time PCR and 16S pyrosequencing the results identified significant inter- and intra-species differences, insight into the successional changes that occur during development and how fasting influences microbial composition

Characterisation of the complete mitochondrial genome and 13 microsatellite loci through next-generation sequencing for the New Caledonian spider-ant Leptomyrmex pallens

The complete mitochondrial genome and a set of polymorphic microsatellite markers were identified by 454 pyrosequencing (1/16th of a plate) for the New Caledonian rainforest spider-ant Leptomyrmex pallens. De novo genome assembly recovered the entire mitochondrial genome with mean coverage of 8.9-fold (range 1-27). The mitogenome consists of 15,591 base pairs including 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a non-coding AT-rich region. The genome arrangement is typical of insect taxa and very similar to the only other published ant mitogenome from the Solenopsis genus, with the main differences consisting of translocations and inversions of tRNAs. A total of 13 polymorphic loci were also characterized using 41 individuals from a single population in the Aoupinié region, corresponding to workers from 21 nests and 16 foraging workers. We observed moderate genetic variation across most loci (mean number of alleles per locus = 4.50; mean expected heterozygosity = 0.53) with evidence of only two loci deviating significantly from Hardy-Weinberg equilibrium due to null alleles. Marker independence was confirmed with tests for linkage disequilibrium. Most loci cross amplified for three additional Leptomyrmex species. The annotation of the mitogenome and characterization of microsatellite markers will provide useful tools for assessing the colony structure, population genetic patterns, and dispersal strategy of L. pallens in the context of rainforest fragmentation in New Caledonia. Furthermore, this paper confirms a recent line of evidence that comprehensive mitochondrial data can be obtained relatively easily from small next-generation sequencing analyses. Greater synthesis of next-generation sequencing data will play a significant role in expanding the taxonomic representation of mitochondrial genome sequences.