Imparting scalephobicity with rational microtexturing of soft materials.

Crystallization fouling, a process where scale forms on surfaces, is widespread in nature and technology, negatively affecting energy and water industries. Despite the effort, rationally designed surfaces that are intrinsically resistant to it remain elusive, due in part to a lack of understanding of how microfoulants deposit and adhere in dynamic aqueous environments. Here, we show that rational tuning of coating compliance and wettability works synergistically with microtexture to enhance microfoulant repellency, characterized by low adhesion and high removal efficiency of numerous individual microparticles and tenacious crystallites in a flowing water environment. We study the microfoulant interfacial dynamics in situ using a micro-scanning fluid dynamic gauge system, elucidate the removal mechanisms, and rationalize the behavior with a shear adhesive moment model. We then demonstrate a rationally developed coating that can remove 98% of deposits under shear flow conditions, 66% better than rigid substrates.

Wildlife gut microbiomes of sympatric generalist species respond differently to anthropogenic landscape disturbances.

BACKGROUND: Human encroachment into nature and the accompanying environmental changes are a big concern for wildlife biodiversity and health. While changes on the macroecological scale, i.e. species community and abundance pattern, are well documented, impacts on the microecological scale, such as the host's microbial community, remain understudied. Particularly, it is unclear if impacts of anthropogenic landscape modification on wildlife gut microbiomes are species-specific. Of special interest are sympatric, generalist species, assumed to be more resilient to environmental changes and which often are well-known pathogen reservoirs and drivers of spill-over events. Here, we analyzed the gut microbiome of three such sympatric, generalist species, one rodent (Proechimys semispinosus) and two marsupials (Didelphis marsupialis and Philander opossum), captured in 28 study sites in four different landscapes in Panama characterized by different degrees of anthropogenic disturbance. RESULTS: Our results show species-specific gut microbial responses to the same landscape disturbances. The gut microbiome of P. semispinosus was less diverse and more heterogeneous in landscapes with close contact with humans, where it contained bacterial taxa associated with humans, their domesticated animals, and potential pathogens. The gut microbiome of D. marsupialis showed similar patterns, but only in the most disturbed landscape. P. opossum, in contrast, showed little gut microbial changes, however, this species' absence in the most fragmented landscapes indicates its sensitivity to long-term isolation. CONCLUSION: These results demonstrate that wildlife gut microbiomes even in generalist species with a large ecological plasticity are impacted by human encroachment into nature, but differ in resilience which can have critical implications on conservation efforts and One Health strategies.

Influence of 1-Butene Adsorption on the Dimerization Activity of Single Metal Cations on UiO-66 Nodes.

Grafting metal cations to missing linker defect sites in zirconium-based metal-organic frameworks, such as UiO-66, produces a uniquely well-defined and homotopic catalytically active site. We present here the synthesis and characterization of a group of UiO-66-supported metal catalysts, M-UiO-66 (M = Ni, Co, Cu, and Cr), for the catalytic dimerization of alkenes. The hydrogen-deuterium exchange via deuterium oxide adsorption followed by infrared spectroscopy showed that the last molecular water ligand desorbs from the sites after evacuation at 300 °C leading to M(OH)-UiO-66 structures. Adsorption of 1-butene is studied using calorimetry and density functional theory techniques to characterize the interactions of the alkene with metal cation sites that are found active for alkene oligomerization. For the most active Ni-UiO-66, the removal of molecular water from the active site significantly increases the 1-butene adsorption enthalpy and almost doubles the catalytic activity for 1-butene dimerization in comparison to the presence of water ligands. Other M-UiO-66 (M = Co, Cu, and Cr) exhibit 1-3 orders of magnitude lower catalytic activities compared to Ni-UiO-66. The catalytic activities correlate linearly with the Gibbs free energy of 1-butene adsorption. Density functional theory calculations probing the Cossee-Arlman mechanism for all metals support the differences in activity, providing a molecular level understanding of the metal site as the active center for 1-butene dimerization.

Disentangling direct from indirect effects of habitat disturbance on multiple components of biodiversity.

Human habitat disturbance affects both species diversity and intraspecific genetic diversity, leading to correlations between these two components of biodiversity (termed species-genetic diversity correlation, SGDC). However, whether SGDC predictions extend to host-associated communities, such as the intestinal parasite and gut microbial diversity, remains largely unexplored. Additionally, the role of dominant generalist species is often neglected despite their importance in shaping the environment experienced by other members of the ecological community, and their role as source, reservoir and vector of zoonotic diseases. New analytical approaches (e.g. structural equation modelling, SEM) can be used to assess SGDC relationships and distinguish among direct and indirect effects of habitat characteristics and disturbance on the various components of biodiversity. With six concrete and biologically sound models in mind, we collected habitat characteristics of 22 study sites from four distinct landscapes located in central Panama. Each landscape differed in the degree of human disturbance and fragmentation measured by several quantitative variables, such as canopy cover, canopy height and understorey density. In terms of biodiversity, we estimated on the one hand, (a) small mammal species diversity, and, on the other hand, (b) genome-wide diversity, (c) intestinal parasite diversity and (d) gut microbial heterogeneity of the most dominant generalist species (Tome's spiny rat, Proechimys semispinosus). We used SEMs to assess the links between habitat characteristics and biological diversity measures. The best supported SEM suggested that habitat characteristics directly and positively affect the richness of small mammals, the genetic diversity of P. semispinosus and its gut microbial heterogeneity. Habitat characteristics did not, however, directly impact intestinal parasite diversity. We also detected indirect, positive effects of habitat characteristics on both host-associated assemblages via small mammal richness. For microbes, this is likely linked to cross species transmission, particularly in shared and/or anthropogenically altered habitats, whereas host diversity mitigates parasite infections. The SEM revealed an additional indirect but negative effect on intestinal parasite diversity via host genetic diversity. Our study showcases that habitat alterations not only affect species diversity and host genetic diversity in parallel, but also species diversity of host-associated assemblages. The impacts from human disturbance are therefore expected to ripple through entire ecosystems with far reaching effects felt even by generalist species.

Las perturbaciones antropogénicas sobre los hábitats naturales pueden afectar tanto a la diversidad de las especies como a la diversidad genética intraespecífica, dando lugar a correlaciones entre estos dos elementos de la biodiversidad (denominados correlación de la diversidad genética de las especies, SGDC por sus siglas en inglés). Sin embargo, todavía queda sin explorar si las predicciones de la SGDC afectan a las comunidades de parásitos y microorganismos intestinales asociadas al hospedador. Adicionalmente, el rol que juegan las especies generalistas, especialmente aquéllas dominantes, suele ser descuidado, a pesar de la importancia de control que ejercen sobre la estructura de la comunidad, y su rol como fuente, reservorio y vector de enfermedades zoonóticas. Para poder evaluar las relaciones de SGDC y distinguir entre los efectos directos e indirectos que tienen las características del hábitat y las perturbaciones sobre los distintos componentes de la biodiversidad, se pueden utilizar nuevos enfoques analíticos como por ejemplo los modelos de ecuaciones estructurales (SEM, por sus siglas en inglés). Considerando seis modelos específicos y biológicamente sólidos, recopilamos las características del hábitat de 22 sitios ubicados en cuatro paisajes distintos situados en el centro de Panamá. Cada paisaje difería en el grado de perturbación antropogénica y fragmentación, medido por diferentes variables cuantitativas, como la cobertura del dosel, la altura del dosel y la densidad del sotobosque. En términos de biodiversidad, por un lado estimamos (1) la diversidad de especies de pequeños mamíferos y, por otro lado (2) la diversidad del genoma completo, (3) la diversidad de parásitos intestinales, y (4) la heterogeneidad de las comunidades microbianas del intestino de la especie generalista más dominante, la rata espinosa de Tomes Proechimys semispinosus. Para evaluar los vínculos entre las características del hábitat y las medidas de diversidad biológica se utilizó el modelado SEM. El SEM mejor apoyado sugirió que las características del hábitat afectan directa y positivamente a la abundancia de pequeños mamíferos, a la diversidad genética de P. semispinosus y a la heterogeneidad microbiana intestinal. Sin embargo, se observó que las características del hábitat no tienen un efecto directo en la diversidad de parásitos intestinales. Aparte de estos efectos directos, detectamos efectos indirectos y positivos de las características del hábitat en ambos conjuntos asociados al hospedador (diversidad de parásitos y microorganismos intestinales) a través de la abundancia de pequeños mamíferos. En el caso de las comunidades microbianas, esto está probablemente relacionado con la transmisión interespecífica, especialmente en hábitats compartidos y/o antropogénicamente alterados; mientras que la diversidad de hospedadores mitiga las infecciones de parásitos. El SEM reveló un efecto indirecto adicional pero negativo sobre la diversidad de parásitos intestinales a través de la diversidad genética de los hospedadores. Nuestro estudio muestra que los patrones de SGDC se filtran a través de las varias capas de diversidad biológica, añadiendo los ensamblajes asociados al hospedador como componentes biológicos afectados por las alteraciones del hábitat.

Complete Genome Sequence of the Collinolactone Producer Streptomyces sp. Strain Gö40/10.

The actinomycete Streptomyces sp. strain Gö40/10 has the potential to produce a range of secondary metabolites, one of which is collinolactone, a compound with neuroprotective properties and potential for pharmaceutical applications. The genome was sequenced with Oxford Nanopore Technologies MinION and Illumina MiSeq systems and consists of a single 9,635,564-nucleotide linear chromosome.

Controlling Reaction Routes in Noble-Metal-Catalyzed Conversion of Aryl Ethers.

Hydrogenolysis and hydrolysis of aryl ethers in the liquid phase are important reactions for accessing functionalized cyclic compounds from renewable feedstocks. On supported noble metals, hydrogenolysis is initiated by a hydrogen addition to the aromatic ring followed by C-O bond cleavage. In water, hydrolysis and hydrogenolysis proceed by partial hydrogenation of the aromatic ring prior to water or hydrogen insertion. The mechanisms are common for the studied metals, but the selectivity to hydrogenolysis increases in the order Pd95 % in water and alkaline conditions.

Role of Zeolite Structural Properties toward Iodine Capture: A Head-to-head Evaluation of Framework Type and Chemical Composition.

This study evaluated zeolite-based sorbents for iodine gas [I2(g)] capture. Based on the framework structures and porosities, five zeolites, including two faujasite (FAU), one ZSM-5 (MFI), one mesoMFI, one ZSM-22 (TON), as well as two mesoporous materials, were evaluated for I2(g) capture at room temperature and 150 °C in an iodine-saturated environment. From these preliminary studies, the three best-performing zeolites were ion-exchanged with Ag+ and evaluated for I2(g) capture under similar conditions. Energy-dispersive X-ray spectroscopy data suggest that Ag-FAU frameworks were the materials with the highest capacity for I2(g) in this study, showing ∼3× higher adsorption compared to Ag-mordenite (Ag-MOR) at room temperature, but X-ray diffraction measurements show that the faujasite structure collapsed during the adsorption studies because of dealumination. The Ag-MFI zeolites are decent sorbents in real-life applications, showing both good sorption capacities and higher stability. In-depth analyses and characterizations, including synchrotron X-ray absorption spectroscopy, revealed the influence of structural and chemical properties of zeolites on the performance for iodine adsorption from the gas phase.

Site Densities, Rates, and Mechanism of Stable Ni/UiO-66 Ethylene Oligomerization Catalysts.

Nickel-functionalized UiO-66 metal organic frameworks (MOFs) oligomerize ethylene in the absence of cocatalysts or initiators after undergoing ethylene-pressure-dependent transients and maintain stable oligomerization rates for >15 days on stream. Higher ethylene pressures shorten induction periods and engender more active sites for ethylene oligomerization; these sites exhibit invariant selectivity-conversion characteristics to justify that only one type of catalytic center is relevant for oligomerization. The number of active sites is estimated using in situ NO titration to disambiguate the effect of increased reaction rates upon exposure to increasing ethylene pressures. After accounting for augmented site densities with increasing ethylene pressures, ethylene oligomerization is first order in ethylene pressure from 100 to 1800 kPa with an activation energy of 81 kJ mol-1 at temperatures from 443-503 K on Ni/UiO-66. A representative Ni/UiO-66 cluster model that mimics high ethylene pressure process conditions is validated with ab initio thermodynamic analysis, and the Cossee-Arlman mechanism is posited based on comparisons between experimental and computed activation enthalpies from density functional theory calculations on these cluster models of Ni/UiO-66. The insights gained from experiment and theory help rationalize evolution in structure and stability for ethylene oligomerization Ni/UiO-66 MOF catalysts.

The Structure of Cyclodecatriene Collinolactone, its Biosynthesis, and Semisynthetic Analogues: Effects of Monoastral Phenotype and Protection from Intracellular Oxidative Stress.

Recently described rhizolutin and collinolactone isolated from Streptomyces Gö 40/10 share the same novel carbon scaffold. Analyses by NMR and X-Ray crystallography verify the structure of collinolactone and propose a revision of rhizolutin's stereochemistry. Isotope-labeled precursor feeding shows that collinolactone is biosynthesized via type I polyketide synthase with Baeyer-Villiger oxidation. CRISPR-based genetic strategies led to the identification of the biosynthetic gene cluster and a high-production strain. Chemical semisyntheses yielded collinolactone analogues with inhibitory effects on L929 cell line. Fluorescence microscopy revealed that only particular analogues induce monopolar spindles impairing cell division in mitosis. Inspired by the Alzheimer-protective activity of rhizolutin, we investigated the neuroprotective effects of collinolactone and its analogues on glutamate-sensitive cells (HT22) and indeed, natural collinolactone displays distinct neuroprotection from intracellular oxidative stress.

Human encroachment into wildlife gut microbiomes.

In the Anthropocene, humans, domesticated animals, wildlife, and their environments are interconnected, especially as humans advance further into wildlife habitats. Wildlife gut microbiomes play a vital role in host health. Changes to wildlife gut microbiomes due to anthropogenic disturbances, such as habitat fragmentation, can disrupt natural gut microbiota homeostasis and make animals vulnerable to infections that may become zoonotic. However, it remains unclear whether the disruption to wildlife gut microbiomes is caused by habitat fragmentation per se or the combination of habitat fragmentation with additional anthropogenic disturbances, such as contact with humans, domesticated animals, invasive species, and their pathogens. Here, we show that habitat fragmentation per se does not impact the gut microbiome of a generalist rodent species native to Central America, Tome's spiny rat Proechimys semispinosus, but additional anthropogenic disturbances do. Indeed, compared to protected continuous and fragmented forest landscapes that are largely untouched by other human activities, the gut microbiomes of spiny rats inhabiting human-disturbed fragmented landscapes revealed a reduced alpha diversity and a shifted and more dispersed beta diversity. Their microbiomes contained more taxa associated with domesticated animals and their potential pathogens, suggesting a shift in potential metagenome functions. On the one hand, the compositional shift could indicate a degree of gut microbial adaption known as metagenomic plasticity. On the other hand, the greater variation in community structure and reduced alpha diversity may signal a decline in beneficial microbial functions and illustrate that gut adaption may not catch up with anthropogenic disturbances, even in a generalist species with large phenotypic plasticity, with potentially harmful consequences to both wildlife and human health.

Mammalian deltavirus without hepadnavirus coinfection in the neotropical rodent Proechimys semispinosus.

Hepatitis delta virus (HDV) is a human hepatitis-causing RNA virus, unrelated to any other taxonomic group of RNA viruses. Its occurrence as a satellite virus of hepatitis B virus (HBV) is a singular case in animal virology for which no consensus evolutionary explanation exists. Here we present a mammalian deltavirus that does not occur in humans, identified in the neotropical rodent species Proechimys semispinosus The rodent deltavirus is highly distinct, showing a common ancestor with a recently described deltavirus in snakes. Reverse genetics based on a tandem minus-strand complementary DNA genome copy under the control of a cytomegalovirus (CMV) promoter confirms autonomous genome replication in transfected cells, with initiation of replication from the upstream genome copy. In contrast to HDV, a large delta antigen is not expressed and the farnesylation motif critical for HBV interaction is absent from a genome region that might correspond to a hypothetical rodent large delta antigen. Correspondingly, there is no evidence for coinfection with an HBV-related hepadnavirus based on virus detection and serology in any deltavirus-positive animal. No other coinfecting viruses were detected by RNA sequencing studies of 120 wild-caught animals that could serve as a potential helper virus. The presence of virus in blood and pronounced detection in reproductively active males suggest horizontal transmission linked to competitive behavior. Our study establishes a nonhuman, mammalian deltavirus that occurs as a horizontally transmitted infection, is potentially cleared by immune response, is not focused in the liver, and possibly does not require helper virus coinfection.

Pathogen-associated selection on innate immunity genes (TLR4, TLR7) in a neotropical rodent in landscapes differing in anthropogenic disturbance.

Toll-like receptors (TLRs) form part of the innate immune system and can recognize structurally conserved pathogen-associated molecular pattern (PAMP) molecules. Their functional importance in the resistance to pathogens has been documented in laboratory experimental settings and in humans. TLR diversity, however, has been rarely investigated in wildlife species. How the genetic diversity of TLRs is associated with various pathogens and how it is shaped by habitat disturbance are understudied. Therefore, we investigated the role of genetic diversity in the functionally important parts of TLR4 and TLR7 genes in resistance towards gastrointestinal nematodes and Hepacivirus infection. We chose a generalist study species, the rodent Proechimys semispinosus, because it is highly abundant in three Panamanian landscapes that differ in their degree of anthropogenic modification. We detected only two TLR7 haplotypes that differed by one synonymous single-nucleotide polymorphism (SNP) position. The TLR4 variability was higher, and we detected four TLR4 haplotypes that differed at one synonymous SNP and at three amino acid positions within the leucine-rich repeat region. Only TLR4 haplotypes had different frequencies in each landscape. Using generalized linear models, we found evidence that nematode loads and virus prevalence were influenced by both specific TLR4 haplotypes and landscape. Here, the variable "landscape" served as a surrogate for the important influential ecological factors distinguishing landscapes in our study, i.e. species diversity and host population density. Individuals carrying the common TLR4_Ht1 haplotype were less intensely infected by the most abundant strongyle nematode. Individuals carrying the rare TLR4_Ht3 haplotype were all Hepacivirus-positive, where those carrying the rare haplotype TLR4_Ht4 were less often infected by Hepacivirus than individuals with other haplotypes. Our study highlights the role of TLR diversity in pathogen resistance and the importance of considering immune genetic as well as ecological factors in order to understand the effects of anthropogenic changes on wildlife health.

Antimicrobial Effect of Visible Light-Photoinactivation of Legionella rubrilucens by Irradiation at 450, 470, and 620 nm.

Despite the high number of legionella infections, there are currently no convincing preventive measures. Photoinactivation with visible light is a promising new approach and the photoinactivation sensitivity properties of planktonic Legionella rubrilucens to 450, 470, and 620 nm irradiation were thus investigated and compared to existing 405 nm inactivation data for obtaining information on responsible endogenous photosensitizers. Legionella were streaked on agar plates and irradiated with different doses by light emitting diodes (LEDs) of different visible wavelengths. When irradiating bacterial samples with blue light of 450 nm, a 5-log reduction could be achieved by applying a dose of 300 J cm-2, whereas at 470 nm, a comparable reduction required about 500 J cm-2. For red irradiation at 620 nm, no inactivation could be observed, even at 500 J cm-2. The declining photoinactivation sensitivity with an increasing wavelength is consistent with the assumption of porphyrins and flavins being among the relevant photosensitizers. These results were obtained for L. rubrilucens, but there is reason to believe that its inactivation behavior is similar to that of pathogenic legionella species. Therefore, this photoinactivation might lead to new future concepts for legionella reduction and prevention in technical applications or even on or inside the human body.

Ecological drivers of Hepacivirus infection in a neotropical rodent inhabiting landscapes with various degrees of human environmental change.

Anthropogenic environmental change can impact community and population traits such as species diversity and population densities, which have been shown to influence the prevalence of viruses in wildlife reservoirs. In particular, host species resilient to changes in their natural habitat may increase in numbers, which in turn can affect the prevalence of directly transmitted viruses. We have carried out a survey of small mammal communities in three tropical landscapes differing in their degree of environmental change in Central Panama and investigated the effects of community changes on Hepacivirus prevalence. The modification of continuous habitat into partly connected or isolated habitat patches during the past century was linked to changes in species diversity and species assemblages, which was further associated with shifts in the abundance of generalist marsupial (Didelphis marsupialis, Philander opossum) and rodent (Proechimys semispinosus) species. The latter has become dominant in isolated habitat patches and was the only identified Hepacivirus host in our study system. Our analyses suggest that, in addition to the effects of host age and sex, host population density in interaction with sex ratio is a crucial predictor of infection probability. Although we found no significant relationships between species diversity per se and infection probability, the lowest prevalence detected in the landscape with the highest species diversity indicates that shifts in species assemblages (e.g. changes in the presence and abundance of marsupial predators) impact the host's intraspecific contact rates, the probability of virus transmission and, thus, the virus prevalence. Our study additionally provides important data on the influence of human-induced landscape changes on infection probability and, therefore, on virus prevalence in wildlife and emphasizes the importance of a landscape-scale approach with concomitant consideration of the complex interactions between ecological factors.

UV-C inactivation of Legionella rubrilucens.

Background: Despite the great health significance of Legionella, there is only little information on their UV sensitivity. Besides Legionella pneumophila only L. longbeachae has been investigated so far. Methods: In this study L. rubrilucens has been spread on buffered charcoal yeast extract agar and irradiated with the 254 nm UV-C emission of a mercury vapor lamp. The disinfection success is measured by colony counting after incubation and comparison of the number of colonies on irradiated and unirradiated reference agar plates. Results: The average log-reduction dose is 1.08 mJ/cm2 for free L. rubrilucens, which is at the lower end of the so far published Legionella log-reduction values, but all three Legionella species show similar UV-C sensitivities. Conclusion: The log-reduction dose of legionellae in amoebae has not been investigated, but with the observed high UV-C sensitivity for free Legionella, the idea of a future point-of-use disinfection by small UV-C LEDs in water-taps or shower heads appears to be realistic, even if legionellae are more resistant in amoebae.