Human streptococcus agalactiae strains in aquatic mammals and fish

<p>Background: In humans, Streptococcus agalactiae or group B streptococcus (GBS) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. In addition, Streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. We studied the molecular epidemiology of S. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic species and humans.</p> <p>Methods: Isolates from fish (n = 26), seals (n = 6), a dolphin and a frog were characterized by pulsed-field gel electrophoresis, multilocus sequence typing and standardized 3-set genotyping, i.e. molecular serotyping and profiling of surface protein genes and mobile genetic elements.</p> <p>Results: Four subpopulations of S. agalactiae were identified among aquatic isolates. Sequence type (ST) 283 serotype III-4 and its novel single locus variant ST491 were detected in fish from Southeast Asia and shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. The human pathogenic strain ST7 serotype Ia was also detected in fish from Asia. ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens. The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans.</p> <p>Conclusions: The apparent association of the four subpopulations of S. agalactiae with specific groups of host species suggests that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains.</p&gt

Fire interval and post-fire climate effects on serotinous forest resilience

Background Climate change is eroding forest resilience to disturbance directly through warming climate and indirectly through increasing disturbance activity. Forests characterized by stand-replacing fire regimes and dominated by serotinous species are at risk when the inter-fire period is insufficient for canopy seed bank development and climate conditions for recruitment in the post-fire growing season are unsuitable. Although both factors are critical to serotinous forest persistence, their relative importance for post-fire regeneration in serotinous forests remains poorly understood. To assess the relative effects of each factor, we established plots in severely burned knobcone pine (Pinus attenuata Lemmon) forests in Oregon and California, USA, representing a range of past fire intervals (6 to 31+ years). Specifically, we evaluated effects of fire interval and pre-fire canopy seed bank (proxies for seed supply) and post-fire climate on three metrics of post-fire tree regeneration (seedling density, probability of self-replacement, percent population recovery). Results Seed supply consistently had the strongest effect on post-fire regeneration. Between 6- and 31-year fire intervals, post-fire seedling density increased from 1000 to 100,000 seedlings ha−1, while probability of self-replacement increased from ~ 0 to ~ 100% and percent population recovery increased from 20 to 2000% of the pre-fire population, respectively. Similarly, increasing the canopy seed bank by two orders of magnitude increased seedling density and percent population recovery by two orders and one order of magnitude, respectively, and increased the probability of self-replacement by > 50%. Greater post-fire climatic moisture deficit exacerbated the effect of seed supply; an additional 4–6 years between fires was required under high moisture stress conditions to reach similar regeneration levels as under low moisture stress conditions. Conclusion The overriding effect of seed supply—strongly driven by pre-fire stand age—on post-fire regeneration suggests that altered fire frequency (an indirect effect of climate change) will have a profound impact on serotinous forests. Although direct effects of hot and dry climate are lower in magnitude, they can alter forest recovery where seed supply nears a threshold. These findings reveal how fire interval and climate combine to determine changes in forest cover in the future, informing management and vulnerability mapping

How plants connect pollination and herbivory networks and their contribution to community stability

Pollination and herbivory networks have mainly been studied separately, highlighting their distinct structural characteristics and the related processes and dynamics. However, most plants interact with both pollinators and herbivores, and there is evidence that both types of interaction affect each other. Here we investigated the way plants connect these mutualistic and antagonistic networks together, and the consequences for community stability. Using an empirical data set, we show that the way plants connect pollination and herbivory networks is not random and promotes community stability. Analyses of the structure of binary and quantitative networks show different results: the plants’ generalism with regard to pollinators is positively correlated to their generalism with regard to herbivores when considering binary interactions, but not when considering quantitative interactions. We also show that plants that share the same pollinators do not share the same herbivores. However, the way plants connect pollination and herbivory networks promotes stability for both binary and quantitative networks. Our results highlight the relevance of considering the diversity of interaction types in ecological communities, and stress the need to better quantify the costs and benefits of interactions, as well as to develop new metrics characterizing the way different interaction types are combined within ecological networks

Long-term feeding ecology and habitat use in harbour porpoises <i>Phocoena phocoena</i> from Scandinavian waters inferred from trace elements and stable isotopes

Background. We investigated the feeding ecology and habitat use of 32 harbour porpoises by-caught in 4 localities along the Scandinavian coast from the North Sea to the Barents Sea using time-integrative markers: stable isotopes (δ13C, δ15N) and trace elements (Zn, Cu, Fe, Se, total Hg and Cd), in relation to habitat characteristics (bathymetry) and geographic position (latitude). Results. Among the trace elements analysed, only Cd, with an oceanic specific food origin, was found to be useful as an ecological tracer. All other trace elements studied were not useful, most likely because of physiological regulation and/or few specific sources in the food web. The δ13C, δ15N signatures and Cd levels were highly correlated with each other, as well as with local bathymetry and geographic position (latitude). Variation in the isotopic ratios indicated a shift in harbour porpoise's feeding habits from pelagic prey species in deep northern waters to more coastal and/or demersal prey in the relatively shallow North Sea and Skagerrak waters. This result is consistent with stomach content analyses found in the literature. This shift was associated with a northward Cd-enrichment which provides further support to the Cd 'anomaly' previously reported in polar waters and suggests that porpoises in deep northern waters include Cd-contaminated prey in their diet, such as oceanic cephalopods. Conclusion. As stable isotopes and Cd provide information in the medium and the long term respectively, the spatial variation found, shows that harbour porpoises experience different ecological regimes during the year along the Scandinavian coasts, adapting their feeding habits to local oceanographic conditions, without performing extensive migration

Assessing the effectiveness of the Birdsbesafe® anti-predation collar cover in reducing predation on wildlife by pet cats in Western Australia

Many pet cats hunt and, irrespective of whether or not this threatens wildlife populations, distressed owners may wish to curtail hunting while allowing their pets to roam. Therefore we evaluated the effectiveness of three patterned designs (simple descriptions being rainbow, red and yellow) of the anti-predation collar cover, the Birdsbesafe® (BBS), in reducing prey captures by 114 pet cats over 2 years in a suburban Australian context. The BBS offers a colourful indicator of a cat's presence and should therefore alert prey with good colour vision (birds and herpetofauna), but not most mammals with limited colour vision. We also interviewed the 82 owners of cats in the study about their experience using the BBS and their assessment of the behavioural responses of their cats. In the first year of the study, which focused on the effectiveness of different BBS colours, captures of prey with good colour vision were reduced by 54% (95% CL 43-64%) when cats were wearing a BBS of any colour, with the rainbow and red BBS more effective than the yellow when birds were prey. Captures of mammals were not reduced significantly. The second year assessed the rainbow BBS alone, and those data combined with rainbow data in the first year found a significant reduction of 47% (95% CL 43-57%) in capture of prey with good colour vision, with no effect of differences across years. We found no evidence that cats maintained a lower predation rate once the BBS was removed. Seventy-nine per cent of owners reported that their cats had no problems with the BBS and another 17% reported that their cats adjusted within 2 days. Fourteen owners reported that their cats spent more time at home and ate more while wearing the BBS. Two owners reported their cats stayed away from home more while wearing it. Sixty-four per cent of owners using the red collar, 48% using rainbow and 46% using yellow believed that it worked. Overall, 77% of owners planned to continue using the BBS after the study had finished. The BBS is an option for owners wishing to reduce captures of birds and herpetofauna by free-ranging cats, especially where mammalian prey are introduced pests. To date, the BBS is the only predation deterrent that reduces significantly the number of herpetofauna brought home. It is unsuitable where endangered mammalian prey or large invertebrates are vulnerable to predation by pet cats

Opipramol inhibits lipolysis in human adipocytes without altering glucose uptake and differently from antipsychotic and antidepressant drugs with adverse effects on body weight control

Treatment with several antipsychotic drugs exhibits a tendency to induce weight gain and diabetic complications. The proposed mechanisms by which the atypical antipsychotic drug olanzapine increases body weight include central dysregulations leading to hyperphagia and direct peripheral impairment of fat cell lipolysis. Several investigations have reproduced in vitro direct actions of antipsychotics on rodent adipocytes, cultured preadipocytes, or human adipose tissue-derived stem cells. However, to our knowledge, no such direct action has been described in human mature adipocytes. The aim of the present study was to compare in human adipocytes the putative direct alterations of lipolysis by antipsychotics (haloperidol, olanzapine, ziprazidone, risperidone), antidepressants (pargyline, phenelzine), or anxiolytics (opipramol). Lipolytic responses to the tested drugs, and to recognized lipolytic (e.g., isoprenaline) or antilipolytic agents (e.g., insulin) were determined, together with glucose transport and amine oxidase activities in abdominal subcutaneous adipocytes from individuals undergoing plastic surgery. None of the tested drugs were lipolytic. Surprisingly, only opipramol exhibited substantial antilipolytic properties in the micromolar to millimolar range. An opipramol antilipolytic effect was evident against isoprenaline-, forskolin-, or atrial natriuretic peptide-stimulated lipolysis. Opipramol did not impair insulin activation of glucose transport but inhibited monoamine oxidase (MAO) activity to the same extent as antidepressants recognized as MAO inhibitors (pargyline, harmine, or phenelzine), whereas antipsychotics were inefficient. Considering its unique properties, opipramol, which is not associated with weight gain in treated patients, is a good candidate for drug repurposing because it limits exaggerated lipolysis, prevents hydrogen peroxide release by amine oxidases in adipocytes, and is thereby of potential use to limit lipotoxicity and oxidative stress, two deleterious complications of diabetes and obesity

Microbiome composition is shaped by geography and population structure in the parasitic wasp Asobara japonica, but not in the presence of the endosymbiont Wolbachia

The microbial community composition is crucial for diverse life-history traits in many organisms. However, we still lack a sufficient understanding of how the host microbiome is acquired and maintained, a pressing issue in times of global environmental change. Here we investigated to what extent host genotype, environmental conditions, and the endosymbiont Wolbachia influence the bacterial communities in the parasitic wasp Asobara japonica. We sampled multiple wasp populations across 10 locations in their natural distribution range in Japan and sequenced the host genome (whole genome sequencing) and microbiome (16S rRNA gene). We compared the host population structure and bacterial community composition of wasps that reproduce sexually and are uninfected with Wolbachia with wasps that reproduce asexually and carry Wolbachia. The bacterial communities in asexual wasps were highly similar due to a strong effect of Wolbachia rather than host genomic structure. In contrast, in sexual wasps, bacterial communities appear primarily shaped by a combination of population structure and environmental conditions. Our research highlights that multiple factors shape the bacterial communities of an organism and that the presence of a single endosymbiont can strongly alter their compositions. This information is crucial to understanding how organisms and their associated microbiome will react in the face of environmental change

Mitochondrial variation in Anopheles gambiae and Anopheles coluzzii: phylogeographic legacy and mitonuclear associations with metabolic resistance to pathogens and insecticides

Mitochondrial DNA has been a popular marker in phylogeography, phylogeny, and molecular ecology, but its complex evolution is increasingly recognized. Here, we investigated mitochondrial DNA variation in Anopheles gambiae and Anopheles coluzzii, in relation to other species in the Anopheles gambiae complex, by assembling the mitogenomes of 1,219 mosquitoes across Africa. The mitochondrial DNA phylogeny of the Anopheles gambiae complex was consistent with previously reported highly reticulated evolutionary history, revealing important discordances with the species tree. The three most widespread species (An. gambiae, An. coluzzii, and Anopheles arabiensis), known for extensive historical introgression, could not be discriminated based on mitogenomes. Furthermore, a monophyletic clustering of the three saltwater-tolerant species (Anopheles merus, Anopheles melas, and Anopheles bwambae) in the Anopheles gambiae complex also suggested that introgression and possibly selection shaped mitochondrial DNA evolution. Mitochondrial DNA variation in An. gambiae and An. coluzzii across Africa revealed significant partitioning among populations and species. A peculiar mitochondrial DNA lineage found predominantly in An. coluzzii and in the hybrid taxon of the African “far-west” exhibited divergence comparable to the interspecies divergence in the Anopheles gambiae complex, with a geographic distribution matching closely An. coluzzii's geographic range. This phylogeographic relict of the An. coluzzii and An. gambiae split was associated with population and species structure, but not with the rare Wolbachia occurrence. The lineage was significantly associated with single nucleotide polymorphisms in the nuclear genome, particularly in genes associated with pathogen and insecticide resistance. These findings underline potential mitonuclear coevolution history and the role played by mitochondria in shaping metabolic responses to pathogens and insecticides in Anopheles

Mixing of porpoise ecotypes in southwestern UK waters revealed by genetic profiling

Contact zones between ecotypes are windows for understanding how species may react to climate changes. Here, we analysed the fine-scale genetic and morphological variation in harbour porpoises (Phocoena phocoena) around the UK by genotyping 591 stranded animals at nine microsatellite loci. The data were integrated with a prior study to map at high resolution the contact zone between two previously identified ecotypes meeting in the northern Bay of Biscay. Clustering and spatial analyses revealed that UK porpoises are derived from two genetic pools with porpoises from the southwestern UK being genetically differentiated, and having larger body sizes compared to those of other UK areas. Southwestern UK porpoises showed admixed ancestry between southern and northern ecotypes with a contact zone extending from the northern Bay of Biscay to the Celtic Sea and Channel. Around the UK, ancestry blends from one genetic group to the other along a southwest--northeast axis, correlating with body size variation, consistent with previously reported morphological differences between the two ecotypes. We also detected isolation by distance among juveniles but not in adults, suggesting that stranded juveniles display reduced intergenerational dispersal. The fine-scale structure of this admixture zone raises the question of how it will respond to future climate change and provides a reference point for further study