Non-specific association between filamentous bacteria and fungus-growing ants

Fungus-growing ants and their fungal cultivar form a highly evolved mutualism that is negatively affected by the specialized parasitic fungus Escovopsis. Filamentous Pseudonocardia bacteria occurring on the cuticle of attine ants have been proposed to form a mutualistic interaction with these ants in which they are vertically transmitted (i.e. from parent to offspring colonies). Given a strictly vertical transmission of Pseudonocardia, the evolutionary theory predicts a reduced genetic variability of symbionts among ant lineages. The aim of this study was to verify whether actinomycetes, which occur on Acromyrmex octospinosus leaf-cutting ants, meet this expectation by comparing their genotypic variability with restriction fragment length polymorphisms. Multiple actinomycete strains could be isolated from both individual ant workers and colonies (one to seven strains per colony). The colony specificity of actinomycete communities was high: Only 15% of all strains were isolated from more than one colony, and just 5% were present in both populations investigated. Partial sequencing of 16S ribosomal deoxyribonucleic acid of two of the isolated strains assigned both of them to the genus Streptomyces. Actinomycetes could also be isolated from workers of the two non-attine ant species Myrmica rugulosa and Lasius flavus. Sixty-two percent of the strains derived from attine ants and 80% of the strains isolated from non-attine ants inhibited the growth of Escovopsis. Our data suggest that the association between attine ants and their actinomycete symbionts is less specific then previously thought. Soil-dwelling actinomycetes may have been dynamically recruited from the environment (horizontal transmission), probably reflecting an adaptation to a diverse community of microbial pathogens.     

A fast one-pot synthesize of crystalline anglesite by hydrothermal synthesis for environmental assessment on pure phase

Environmental Science and Pollution Research - Anglesite (PbSO4) is a lead sulfate that belongs to the barite group and is naturally ubiquitous in the environment. This work describes a simple way...     

Announcing the 2022 Arnold Berliner Award Winner: spider research at the International Space Station

The Science of Nature - Migration is used by many species as a strategy to deal with a seasonally changing environment. For some species, migration patterns can vary across different or even within...     

The impacts of warfare and armed conflict on land systems

ABSTRACT

Land-use decisions can change abruptly in response to shocks, and warfare and armed conflicts are among the most drastic and globally frequent shocks. Yet, our understanding of where armed conflict affects land systems, how land-use patterns are impacted, and how far-reaching and persistent these changes are, is partial. We used a spatially detailed dataset on armed conflict and a literature review to explore these questions. A number of key insights emerged from our study: (1) warfare and armed conflict affect land systems mainly in more densely populated areas, regardless of the dominating land use; (2) warfare and armed conflict can impact land systems in major ways, but these effects are diverse and not unidirectional; (3) warfare and armed conflict primarily affects land systems locally, but can forge telecouplings; and (4) although the impact of warfare and armed conflict is often immediate, it can instigate long-lasting land-use legacies.     

Dioxin alters inflammatory responses to lipopolysaccharide

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has well characterized effects on specific immune responses, but the effects on the innate immune system are less understood. The effect of TCDD on inflammatory responses induced by lipopolysaccharide (LPS) was evaluated in C57BL/6J female mice. Mice were treated with 30?µg?kg^?1 TCDD or vehicle once, p.o., and 4 days later, animals received LPS (0.05?×?10⁷?EU?kg^?1, i.p.) or vehicle. Inflammatory mediators and the liver injury marker, alanine aminotransferase (ALT), were measured, and liver histology was evaluated. TCDD-treated animals had higher plasma ALT activity than vehicle-treated animals, but the effect was mild and time-dependent. Few changes in liver histopathology were observed, mainly represented in greater steatosis in TCDD/LPS-treated mice compared to mice treated with LPS or TCDD alone. LPS produced a time-dependent increase in the plasma concentrations of interleukins (IL)-6, -10, and -12 and interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein (MCP)-1. With the exception of IL-12, concentrations of each of these mediators were higher in plasma of mice co-treated with TCDD and LPS compared to either agent alone. The dose–response curve for the concentration of IL-6 in plasma suggested that dioxin increased the potency of LPS to cause the release of this cytokine but not the maximal response. Co-treatment with TCDD and LPS also led to greater expression of mRNA for IL-10 and IFN-γ compared to either TCDD or LPS alone. These results suggest that TCDD changes the inflammatory cytokine profile induced by LPS and that LPS enhances the hepatic steatotic response to TCDD.     

Variation along the shy–bold continuum in extremophile fishes (<Emphasis Type="BoldItalic">Poecilia mexicana</Emphasis>, <Emphasis Type="BoldItalic">Poecilia sulphuraria</Emphasis>)

One potential trade-off that bold individuals face is between increased predation risks and gains in resources. Individuals experiencing high predation and hungry individuals (or individuals with low body condition) are predicted to show increased boldness. We examined one behavioral trait previously reported to be associated with boldness (the time individual fish needed to emerge from shelter) in various populations of mollies (Poecilia spp.). Our study system included several southern Mexican surface streams with high piscine predation and high food availability, sulfidic surface streams with high avian predation, in which the inhabiting fish show reduced body condition, and a sulfidic cave, where predation and body condition are low. Our comparison revealed very short times to emerge from the start box in populations from non-sulfidic streams. In sulfidic habitats (whether surface or cave), it took individual Poecilia mexicana considerably longer to emerge from the start box, and the same difference was also found in an independent comparison between P. mexicana and the closely related, highly sulfide-adapted Poecilia sulphuraria. Fish reared under common garden conditions (in the absence of predators and hydrogen sulfide) showed intermediate boldness scores to the extremes observed in the field. Our data thus indicate that (a) boldness is shaped by environmental conditions/experiential effects, but is not heritable, (b) predation affects boldness in the predicted direction, but (c) low body condition leads to reduced boldness. Extremophile Poecilia spp. spend most of their time surfacing to survive under sulfidic and hypoxic conditions, which exposes them to increased levels of predations, but the fish forage on the bottom. Hence, in this system, increased boldness does not increase foraging success. We argue that energy limitation favors reducing energetically costly behaviors, and exploring novel environments may be just one of them.     

Determination of the optimum MM5 configuration for long term CMAQ simulations of aerosol bound pollutants in Europe

Realistic meteorological fields are a prerequisite for the determination of pollutant concentrations and depositions by means of a chemistry transport model. Different configurations of the 5th generation NCAR/Penn State University mesoscale meteorological model MM5 were tested to determine the optimum set up for long term hindcasts that cover several months up to years. Four dimensional data assimilation (FDDA) significantly enhances the spatio temporal representation of temperature, humidity and wind. Best agreement with radiosonde observations could be achieved when temperature, humidity and wind were grid nudged every 6 h. The quality of the resulting meteorological fields showed no significant systematic temporal or spatial variation over Europe in a model run of the year 2000. It was found that the hydrological cycle was not correctly reproduced by the model when no nudging was applied. The relevant model run showed too high relative humidity and too high rainfall when compared to observations. This led to considerably lower aerosol concentrations close to ground and a shift in the deposition patterns of particle bound pollutants like the carcinogenic benzo(a)pyrene (B(a)P). Guest Editor: Dr. S. T. Rao.     

Essential fatty acid (docosahexaenoic acid, DHA) availability affects growth of larval herring in the field

Larval fish growth and survival depends not only on prey quantity, but also on prey quality. To investigate effects of prey fatty acid concentration on larval herring growth, we collected different prey organisms and larval herring (Clupea harengus L.) in the Kiel Canal during the spring season of 2009. Along with biotic background data, we analysed fatty acids both in prey organisms and in the larvae and used biochemically derived growth rates of the larvae as the response variable. Larval herring reached their highest RNA/DNA derived growth rates only at high docosahexaenoic acid (DHA) concentration. When the ratio of copepodids to lesser quality cirriped nauplii was low, larval growth and larval DHA concentration were both significantly negatively affected. This was true even as prey abundance was increasing. This finding indicates that even in mixed, natural feeding conditions, growth variations are associated with DHA availability in larval fish.     

Quantifying the uncertainty of variance partitioning estimates of ecological datasets

Environmental and Ecological Statistics - An important objective of experimental biology is the quantification of the relationship between sets of predictor and response variables, a statistical...     

A unified approach for including non-extractable residues (NER) of chemicals and pesticides in the assessment of persistence

All chemicals form non-extractable residues (NER) to various extents in environmental media like soil, sediment, plants and animals. NER can be quantified in environmental fate studies using isotope-labeled (such as ¹⁴C or ¹³C) tracer compounds. Previous NER definitions have led to a mismatch of legislation and state of knowledge in research: the residues are assumed to be either irreversibly bound degradation products or at least parts of these residues can be released. In the latter assumption, soils and sediments are a long-term source of slowly released residues. We here present a conceptual experimental and modeling approach to characterize non-extractable residues and provide guidance how they should be considered in the persistence assessment of chemicals and pesticides. Three types of NER can be experimentally discriminated: sequestered and entrapped residues (type I), containing either the parent substance or xenobiotic transformation products or both and having the potential to be released, which has indeed been observed. Type II NER are residues that are covalently bound to organic matter in soils or sediments or to biological tissue in organisms and that are considered being strongly bound with very low remobilization rates like that of humic matter degradation rates. Type III NER comprises biogenic NER (bioNER) after degradation of the xenobiotic chemical and anabolic formation of natural biomolecules like amino acids and phospholipids, and other biomass compounds. We developed the microbial turnover to biomass (MTB) model to predict the formation of bioNER based on the structural properties of chemicals. Further, we proposed an extraction sequence to obtain a matrix containing only NER. Finally, we summarized experimental methods to distinguish the three NER types. Type I NER and type II NER should be considered as potentially remobilizable residues in persistence assessment but the probability of type II release is much lower than that of type I NER, i.e., type II NER in soil are “operationally spoken” irreversibly bound and can be released only in minute amounts and at very slow rates, if at all. The potential of remobilization can be evaluated by chemical, physical and biological methods. BioNER are of no environmental concern and, therefore, can be assessed as such in persistence assessment. The general concept presented is to consider the total amount of NER minus potential bioNER as the amount of xenoNER, type I?+?II. If a clear differentiation of type I and type II is possible, for the calculation of half-life type I NER are considered as not degraded parent substance or transformation product(s). On the contrary, type II NER may generally be considered as (at least temporarily) removed. Providing proof for type II NER is the most critical issue in NER assessment and requires additional research. If no characterization and additional information on NER are available, it is recommended to assess the total amount as potentially remobilizable. We propose our unified approach of NER characterization and evaluation to be implemented into the persistence and environmental hazard assessment strategies for REACH chemicals and biocides, human and veterinary pharmaceuticals, and pesticides, irrespective of the different regulatory frameworks.