Wolbachia and Spiroplasma endosymbionts in the Anurida maritima (Collembola) species group

A large proportion of arthropods carry maternally-inherited endosymbiotic bacteria with which they have developed close relationships. Some of these endosymbionts are selfish genetic elements and manipulate their hosts’ reproduction to their own advantage, for example via cytoplasmic incompatibility (CI) or male killing. Here we report that the sexually reproducing collembolan Anurida maritima carries two endosymbionts (Wolbachia and Spiroplasma) and provide genome sequences for both bacteria. Phylogenomic analyses indicate that the Wolbachia belong to the A supergroup and that the Spiroplasma are sister to the Citri-Chrysopicola-Mirum lineage. A. maritima is considered a species group and consists of at least two distinct genetic lineages. We show that both lineages carry both endosymbionts. No homologs of the Spiroplasma male-killing gene SpAID were observed within our datasets. Homologs of the male-killing associated wmk and the CI inducing cifA and cifB prophage genes were detected in the Wolbachia genome. Phylogenetic analyses placed the cif genes in the poorly characterised Type V clade. The cifA and cifB gene sequences of the two Anurida lineages are identical. It therefore seems unlikely that the genetic divergence within the species group stems from cifA and cifB induced CI. Laboratory controlled genetic crosses and sex ratio studies will be needed to reveal any potential effect of the two endosymbionts on A. maritima’s reproduction

Black rabbits on Lundy: Tudor treasures or post-war phonies?

Lundy is renowned for its feral black rabbits which, according to popular tradition, have inhabited the island since medieval times. Black rabbit fur was valued for much of the Middle Ages, explaining why warreners of Lundy might have favoured them, but genes responsible for feral rabbit melanism remain unexplored. Further potential complicating factors occur in the form of recent (twentieth century) small-scale domestic rabbit introductions to the Lundy feral population. To gain insight into genetic mechanisms underlying melanism on Lundy, rabbit samples were collected and subjected to molecular analysis. The Lundy rabbit population is shown to harbour non-functional copies of the agouti signalling protein (Asip) gene, a main determinant of coat colour in mammals. The observed genetic mutation is not unique to Lundy, having been reported to underlie dark coat colour phenotypes in various domestic rabbit breeds. The mutation is recessive and only phenotypically expressed in homozygous individuals. Although presence of this particular allele does not preclude recent genetic augmentation or replacement, simple population genetics show that allele persistence from a medieval introduction is not impossible

Resisting antimicrobial resistance: lessons from fungus farming ants

Attine ants use antimicrobials produced by commensal bacteria to inhibit parasites on their fungal gardens. However, in this agricultural system, antimicrobial use does not lead to overwhelming resistance, as is typical in clinical settings. Mixtures of continually evolving antimicrobial variants could support these dynamics. [Abstract copyright: Copyright © 2019 Elsevier Ltd. All rights reserved.

Nature read in tooth and fur: non-invasive sampling of the Pygmy Shrew (Sorex minutus Linnaeus, 1766) on Lundy for population genetics

Britain’s smallest mammal, the pygmy shrew (Sorex minutus Linnaeus, 1766) is the only long established terrestrial mammal on Lundy. Little is known about this species’ mode of colonisation or its population structure on the island. Genetic analyses might provide useful insights in this respect, but DNA samples are difficult to obtain because pygmy shrews can be harmed by sampling methods. Two non invasive methods for obtaining DNA sequences were tested. DNA was extracted from hair samples and from a mandible derived from a bird-pellet. A 612 base pair fragment of the cytochrome oxidase b gene was PCR amplified and sequenced. To investigate the origin of pygmy shrew on Lundy the sequences were analysed in the context of published data. The sequences are most similar to those from the U.K. mainland which supports a British origin of this population

What's on the menu: Drosera rotundifolia diet determination using DNA data

The round-leaved sundew, Drosera rotundifolia, is a carnivorous plant species. On Lundy it is found in the nutrient-poor bog environments of Pondsbury and the northernmost quarry, where it supplements its diet with invertebrate prey. To gain insight into the diet of these two sundew populations a metabarcoding approach was trialled. This is, to our knowledge, the first study to use DNA barcodes to identify Drosera prey. At each site, a 0.25m2 quadrat was placed in a representative Drosera patch and two days’ worth of prey were collected. To identify prey items, Cytochrome c oxidase subunit I (COX1) sequences were obtained and compared to the Barcode of Life database. This revealed that Lundy sundews have a mixed diet. In total at least 20 different prey taxa were detected in the two 0.25m2 areas sampled. Sixteen taxa could be identified to species, indicating that metabarcoding permits accurate species level identification of sundew prey items. The majority of prey taxa were dipterans (two-winged flies), of which several have previously been reported on Lundy. Most prey taxa were detected in only one of the two quadrats examined (Jaccard’s index of Similarity=0.01; ‘dissimilar’). This might indicate that the two Drosera populations feed on distinct prey communities, but more research is needed to confirm this

Antibiotic-resistant genes and bacteria as evolving contaminants of emerging concerns (e-CEC): is it time to include evolution in risk assessment?

The pressing issue of the abundance of antibiotic resistance genes and resistant bacteria in the environment (ARGs and ARB, respectively) requires procedures for assessing the risk to health. The chemo-centric environmental risk assessment models identify hazard(s) in a dose–response manner, obtaining exposure, toxicity, risk, impact and policy. However, this risk assessment approach based on ARGs/ARB evaluation from a quantitative viewpoint shows high unpredictability because ARGs/ARB cannot be considered as standard hazardous molecules: ARB duplicate and ARGs evolve within a biological host. ARGs/ARB are currently listed as Contaminants of Emerging Concern (CEC). In light of such characteristics, we propose to define ARGs/ARB within a new category of evolving CEC (or e-CEC). ARGs/ARB, like any other evolving determinants (e.g., viruses, bacteria, genes), escape environmental controls. When they do so, just one molecule left remaining at a control point can form the origin of a new dangerous and selection-responsive population. As a consequence, perhaps it is time to acknowledge this trait and to include evolutionary concepts within modern risk assessment of e-CEC. In this perspective we analyze the evolutionary responses most likely to influence risk assessment, and we speculate on the means by which current methods could measure evolution. Further work is required to implement and exploit such experimental procedures in future risk assessment protocols

The bacterial urban resistome: recent advances

Cities that are densely populated are reservoirs of antibiotic resistant genes (ARGs). The overall presence of all resistance genes in a specific environment is defined as a resistome. Spatial proximity of surfaces and different hygienic conditions leads to the transfer of antibiotic resistant bacteria (ARB) within urban environments. Built environments, public transportation, green spaces, and citizens’ behaviors all support persistence and transfer of antimicrobial resistances (AMR). Various unique aspects of urban settings that promote spread and resilience of ARGs/ARB are discussed: (i) the role of hospitals and recreational parks as reservoirs; (ii) private and public transportation as carriers of ARGs/ARB; (iii) the role of built environments as a hub for horizontal gene transfer even though they support lower microbial biodiversity than outdoor environments; (iv) the need to employ ecological and evolutionary concepts, such as modeling the fate of a specific ARG/ARB, to gain enhanced health risk assessments. Our understanding and our ability to control the rise of AMR in an urban setting is linked to our knowledge of the network connecting urban reservoirs and the environment

Antifungals, arthropods and antifungal resistance prevention: lessons from ecological interactions

Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods' armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu

The Bacterial Urban Resistome: Recent Advances

Cities that are densely populated are reservoirs of antibiotic resistant genes (ARGs). The overall presence of all resistance genes in a specific environment is defined as a resistome. Spatial proximity of surfaces and different hygienic conditions leads to the transfer of antibiotic resistant bacteria (ARB) within urban environments. Built environments, public transportation, green spaces, and citizens’ behaviors all support persistence and transfer of antimicrobial resistances (AMR). Various unique aspects of urban settings that promote spread and resilience of ARGs/ARB are discussed: (i) the role of hospitals and recreational parks as reservoirs; (ii) private and public transportation as carriers of ARGs/ARB; (iii) the role of built environments as a hub for horizontal gene transfer even though they support lower microbial biodiversity than outdoor environments; (iv) the need to employ ecological and evolutionary concepts, such as modeling the fate of a specific ARG/ARB, to gain enhanced health risk assessments. Our understanding and our ability to control the rise of AMR in an urban setting is linked to our knowledge of the network connecting urban reservoirs and the environment

The impact of an inclusive education intervention on learning outcomes for girls with disabilities within a resource-poor setting

Background: Despite a global commitment to the right to education for persons with disabilities, little is known about how to achieve inclusive education in practice, particularly in low- and middle-income countries (LMICs), where the majority of the world’s people with disabilities reside. Moreover, although exclusion from education is magnified by intersecting gender and socioeconomic inequalities, there is especially little knowledge regarding what approaches to inclusive education are effective amongst girls with disabilities living in resource-poor settings. Objectives: The objective of this article was to assess the impact of an inclusive education intervention led by a non-governmental organisation (NGO) on the educational attainment of girls with disabilities in the resource-poor Lakes region of Kenya. Method: A quasi-experimental design was employed, where the literacy and numeracy educational attainment of the intervention and control groups was compared over two time points a year apart (Time 1 and Time 2; total matched N = 353). During this period, activities pertaining to six core components of a holistic inclusive education model were implemented. Results: Relative to the control group, girls with disabilities in the intervention group reported a greater increase in literacy and numeracy attainment, adjusted for grade and level of functional difficulty. Conclusion: Findings suggest that the intervention was successful in engendering additional improvements in the educational attainment of girls with disabilities from the resource-poor Lakes region of Kenya. Results highlight both the applicability of NGO-led interventions in settings, where national implementation of inclusive education is constrained, and the potential of taking such interventions to scale