Microbes on a bottle: substrate, season and geography influence community composition of microbes colonizing marine plastic debris

Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5–6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae—all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET substrate. Future research is required to investigate microscale functional interactions at the plastic surface

Variation in bacterial, archaeal and fungal community structure and abundance in High Arctic tundra soil

Arctic ecosystems are under pressure from climate change and atmospheric nitrogen (N) deposition. However, knowledge of the ecology of microbial communities and their responses to such challenges in Arctic tundra soil remain limited, despite the central role these organisms play for ecosystem functioning. We utilised a plot-scale experiment in High Arctic tundra on Svalbard to investigate short-term variation (9 days), following simulation of a N deposition event (4 kg N ha?1 yr?1), in the structure and abundance of bacterial, archaeal and fungal communities between organic and mineral soil horizons. T-RFLP analysis showed significant differences between horizons in bacterial and archaeal community structure. Q-PCR analysis showed that fungal abundance did not differ significantly between soil horizons, whilst bacterial and archaeal abundance was significantly higher in mineral than in organic horizons, despite soil water and total C and N contents being significantly greater in the organic horizon. In the organic horizon, bacterial community structure and fungal abundance varied significantly over time. In the mineral horizon, there was significant variation over time in bacterial abundance, in archaeal community structure and in both fungal community structure and abundance. In contrast, N deposition did not lead to significant variation in either the structure or the abundance of microbial communities. This research demonstrates that microbial community structure and abundance can change rapidly (over only a few days) in Arctic tundra soils and also differently between soil horizons in response to different environmental drivers. Moreover, this variability in microbial community structure and abundance is soil horizon- and taxonomic domain-specific, highlighting the importance of investigating microbial communities across all soil horizons and over short periods of time

Interactions between microorganisms and marine microplastics: A call for research

Synthetic thermoplastics constitute the majority by percentage of anthropogenic debris entering the Earth’s oceans. Microplastics (≤5-mm fragments) are rapidly emerging pollutants in marine ecosystems that may transport potentially toxic chemicals into macrobial food webs. This commentary evaluates our knowledge concerning the interactions between marine organisms and microplastics and identifies the lack of microbial research into microplastic contamination as a significant knowledge gap. Microorganisms (bacteria, archaea, and picoeukaryotes) in coastal sediments represent a key category of life with reference to understanding and mitigating the potential adverse effects of microplastics due to their role as drivers of the global functioning of the marine biosphere and as putative mediators of the biodegradation of plastic-associated additives, contaminants, or even the plastics themselves. As such, research into the formation, structure, and activities of microplastic-associated microbial biofilms is essential in order to underpin management decisions aimed at safeguarding the ecological integrity of our seas and oceans

Physiological integration of coral colonies is correlated with bleaching resistance

Inter-module physiological integration of colonial organisms can facilitate colony-wide coordinated responses to stimuli that strengthen colony fitness and stress resistance. In scleractinian corals, whose colonial integration ranges from isolated polyps to a seamless continuum of polyp structures and functions, this coordination improves responses to injury, predation, disease, and stress and may be one of the indications of an evolutionary origin of Symbiodinium symbiosis. However, observations of species-specific coral bleaching patterns suggest that highly integrated coral colonies may be more susceptible to thermal stress, and support the hypothesis that communication pathways between highly integrated polyps facilitate the dissemination of toxic byproducts created during the bleaching response. Here we reassess this hypothesis by parameterizing an integration index using 7 skeletal features that have been historically employed to infer physiological integration. We examine the relationship between this index and bleaching response across a phylogeny of 88 diverse coral species. Correcting for phylogenetic relationships among species in the analyses reveals significant patterns among species characters that could otherwise be obscured in simple cross-species comparisons using standard statistics, whose assumptions of independence are violated by the shared evolutionary history among species. Similar to the observed benefits of in creased coloniality for other types of stressors, the results indicate a significantly reduced bleaching response among coral species with highly integrated colonies

Arctic soil microbial diversity in a changing world

The Arctic region is a unique environment, subject to extreme environmental conditions, shaping life therein and contributing to its sensitivity to environmental change. The Arctic is under increasing environmental pressure from anthropogenic activity and global warming. The unique microbial diversity of Arctic regions, that has a critical role in biogeochemical cycling and in the production of greenhouse gases, will be directly affected by and affect, global changes. This article reviews current knowledge and understanding of microbial taxonomic and functional diversity in Arctic soils, the contributions of microbial diversity to ecosystem processes and their responses to environmental change

Dynamics of extracellular polymeric substance (EPS) production and loss in an estuarine, diatom-dominated, microalgal biofilm over a tidal emersion-immersion period.

We studied patterns of production and loss of four different extracellular polymeric substance (EPS) fractions - colloidal carbohydrates, colloidal EPS (cEPS), hot water (HW)-extracted and hot bicarbonate (HB)-extracted fractions - and community profiles of active (RNA) bacterial communities by use of Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of reverse transcription-polymerase chain reaction amplified 16S rRNA in mudflats in the Colne Estuary, United Kingdom, over two tidal emersion-immersion cycles. Colloidal carbohydrates and intracellular storage carbohydrate (HW) increased during tidal emersion and declined during tidal cover. The dynamics of cEPS and uronic acid content were closely coupled, as were the HB fraction and HB uronic acids. Changes in monosaccharide profiles of HW and HB fractions occurred during the diel period, with some similarity between cEPS and HB fractions. Increasing enzymatic release rates of reducing sugars and increased reducing sugar content were correlated with increased concentrations of colloidal carbohydrate and cEPS during the illuminated emersion period, and with the amount of HB-extracted uronic acids (the most refractory EPS fraction measured). Loss of reducing sugars was high, with sediment concentrations far below those predicted by the measured in situ release rates, T-RFLP analysis revealed no significant shifts in the overall taxonomic composition of the active bacterial community. However, 12 of the 59 terminal restriction fragments identified showed significant changes in relative abundance during the tidal cycle. Changes in the relative abundance of three particular terminal restriction fragments (bacterial taxa) were positively correlated to the rate of extracellular hydrolysis. Losses of chlorophyll a and colloidal and cEPS (up to 50-60) occurred mainly in the first 30 min after tidal cover. About half of this may be owing to in situ degradation, with "wash away" into the water column accounting for the remainder. © 2006, by the American Society of Limnology and Oceanography, Inc

Glycosides of nadifloxacin—synthesis and antibacterial activities against methicillin-resistant Staphylococcus aureus

The increase in the number of bacteria that are resistant to multiple antibiotics poses a serious clinical problem that threatens the health of humans worldwide. Nadifloxacin (1) is a highly potent antibacterial agent with broad-spectrum activity. However, its poor aqueous solubility has limited its use to topical applications. To increase its solubility, it was glycosylated herein to form a range of trans-linked (3a-e) and cis-linked (7a,b) glycosides, each of which was prepared and purified to afford single anomers. The seven glycoside derivatives (3a-e, 7a,b) were examined for potency against eight strains of S. aureus, four of which were methicillin-resistant. Although less potent than free nadifloxacin (1), the α-L-arabinofuransoside (3a) was effective against all strains that were tested (minimum inhibitory concentrations of 1–8 μg/mL compared to 0.1–0.25 μg/mL for nadifloxacin), demonstrating the potential of this glycoside as an antibacterial agent. Estimation of Log P as well as observations made during preparation of these compounds reveal that the solubilities of the glycosides were greatly improved compared with nadifloxacin (1), raising the prospect of its use in oral applications

‘You’re kind of left to your own devices’: a qualitative focus group study of patients with breast, prostate or blood cancer at a hospital in the South West of England, exploring their engagement with exercise and physical activity during cancer treatment and in the months following standard care

Objectives: The aim of this study was to explore the experiences of patients with breast, prostate or blood cancer, regarding their (1) engagement with exercise and physical activity during treatment and in the months following standard care, and (2) the meanings attached to these lifestyle behaviours.Design: A qualitative study using focus groups. The groups were audio recorded, transcribed and analysed using Framework analysis.Setting: A hospital-based cancer treatment centre in the South-West of England.Participants: Eighteen people who had either completed treatment or were currently on maintenance therapy for breast, prostate or blood cancer (non‐Hodgkin lymphoma or Hodgkin lymphoma).Results: Participants reported treatment limiting their ability to engage in exercise and physical activity. However, participants were aware of the physiological, emotional and social benefits of exercise and expressed a desire to maintain a physically active lifestyle before, during and after treatment. They noted a lack of concrete guidance and appropriate exercise classes for people with cancer and felt poorly informed about the type, intensity, duration and frequency of exercise they should be undertaking. As such, participants reported making decisions on their own, relying on their intuition and listening to their bodies to gauge whether they were doing enough exercise (or not).Conclusions: Participants were aware of the benefits of a physically active lifestyle during and following cancer treatment, but were not familiar with exercise and physical activity guidelines for people living with and beyond cancer. There is a need for healthcare professionals, academics and policy makers to determine how exercise and physical activity can be supported in clinical settings in realistic and meaningful ways accommodating individual patient circumstances

‘You’re kind of left to your own devices’: a qualitative focus group study of patients with breast, prostate or blood cancer at a hospital in the South West of England, exploring their engagement with exercise and physical activity during cancer treatment and in the months following standard care

Objectives: The aim of this study was to explore the experiences of patients with breast, prostate or blood cancer, regarding their (1) engagement with exercise and physical activity during treatment and in the months following standard care, and (2) the meanings attached to these lifestyle behaviours.Design: A qualitative study using focus groups. The groups were audio recorded, transcribed and analysed using Framework analysis.Setting: A hospital-based cancer treatment centre in the South-West of England.Participants: Eighteen people who had either completed treatment or were currently on maintenance therapy for breast, prostate or blood cancer (non‐Hodgkin lymphoma or Hodgkin lymphoma).Results: Participants reported treatment limiting their ability to engage in exercise and physical activity. However, participants were aware of the physiological, emotional and social benefits of exercise and expressed a desire to maintain a physically active lifestyle before, during and after treatment. They noted a lack of concrete guidance and appropriate exercise classes for people with cancer and felt poorly informed about the type, intensity, duration and frequency of exercise they should be undertaking. As such, participants reported making decisions on their own, relying on their intuition and listening to their bodies to gauge whether they were doing enough exercise (or not).Conclusions: Participants were aware of the benefits of a physically active lifestyle during and following cancer treatment, but were not familiar with exercise and physical activity guidelines for people living with and beyond cancer. There is a need for healthcare professionals, academics and policy makers to determine how exercise and physical activity can be supported in clinical settings in realistic and meaningful ways accommodating individual patient circumstances