Anti‐Adhesion Activity of Tannins Isolated from the Mangrove Laguncularia racemosa

In the search of new compounds with biofilm‐inhibiting properties, mangroves with their richness of secondary metabolites can be a valuable resource. Crude methanolic leaf extracts from the mangrove Laguncularia racemosa enriched in phenolic substances cause a reduction in initial cell adhesion of Candida glabrata and Candida albicans, but not on Escherichia coli. LC/MS‐guided fractionation of the phenolic compounds resulted in 19 fractions, of which ten were analyzed for their bioactivity against cell adhesion. Effects on cell adhesion and planktonic growth of Escherichia coli, Candida glabrata and Candida albicans were measured in 96‐well microtiter plates in the presence of 0.2 mg ml^?1 of the isolated fractions. Two fractions caused a reduction of cell adhesion of Candida albicans. These fractions containing bioactive compounds were analyzed by LC/MS and NMR spectroscopy. Casuarinin and digalloyl‐hexahydroxydiphenoyl‐glucose were identified in the active fractions, in addition to three signals of ellagitannins. These results indicate a specific mode of action of hydrolysable tannins against cell adhesion of Candida albicans, which needs to be further analyzed.     

Preliminary study on phylogenetic position and delimitation of the ciliate arthrodontous genera of the moss family Mniaceae

The history of the generic and sectional concepts in the traditional moss family Mniaceae is summarised. The division of the Mniaceae into nine genera has been generally accepted. A phylogenetic analysis, based on 35 Mniaceae samples as ingroup and one Leptostomataceae and three Bryaceae samples as outgroups was completed. A total of 113 new sequences were obtained and 4139 aligned characters were included in the combined dataset. Bayesian inferences based on the combined data set showed five well supported clades, which, as a whole, form the monophyletic family Mniaceae. The number of genera in the traditional Mniaceae is 9 and the number of species is 74. All the genera appear monophyletic except Plagiomnium; accepting Orthomnion at the generic level makes Plagiomnium paraphyletic. The principle that only monophyletic taxa are allowed and may be named necessitates the uniting of Plagiomnium and Orthomnion. The necessary combinations are made. The taxonomy of the genera and sections is discussed. Rhizomnium section Macromnium T.J.Kop. & Y.Sun, sect. nov. is described and the new combination Rhizomnium chlorophyllosum (Kindb.) T.J.Kop. is made. The controversy of paraphyly – monophyly in accepting and naming taxa is discussed and Plagiomnium versus Orthomnion given as an example. All the present genera and species seem to have diverged in the area of the Laurasian supercontinent and the speciation of most genera took place in the temperate forested areas of western and eastern North America, Europe and south-eastern Asia.     

Stem cell expression and development of trunk musculature of lesser‐spotted dogfish (Scyliorhinus canicula) reveal differences between sharks and teleosts

This study compares the trunk skeletal muscle anatomy in 870‐ and 2900‐degree‐day‐old lesser‐spotted dogfish larvae (Scyliorhinus canicula) via haematoxylin/eosin staining as well as immunohistochemistry and Western blot analysis. The results showed poorly differentiated muscle formation in the trunk segments in the younger larvae and fully developed skeletal muscle with a division of red and white cells in the older larvae. The stem cell marker PAX7, which is present in all developmental stages of teleost fish, is only expressed in the younger dogfish. The results show the necessity of examining the skeletal muscle development in sharks to understand the evolutional changes from cartilaginous fishes to teleosts.     

Adaptive parasitic manipulation as exemplified by acanthocephalans

Parasites with complex life cycles often change intermediate host traits in order to enhance their transmission to the next host. Acanthocephalans are excellent examples of such parasitic manipulation. Here, we summarise evidence for adaptive parasitic manipulation in this group, provide a comprehensive overview of intermediate host traits affected by these parasites and discuss critical items for parasitic manipulation such as avoidance of infected prey by target hosts and transmission to dead‐end hosts.     

Dynamics of plant nutrient uptake as affected by biopore-associated root growth in arable subsoil

Background and aims

Soil microbial communities influence nutrient cycling, chemistry and structure of soil, and plant productivity. In turn, agronomic practices such as fertilization and crop rotation alter soil physical and chemical properties and consequently soil microbiomes. Understanding the long-term effects of agronomic practices on soil microbiomes is essential for improving agronomic practices to optimize these microbial communities for agricultural sustainability. We examine the composition and substrate-utilization profiles of microbial communities at the Morrow Plots in Illinois.

Methods

Microbial community composition is assessed with 16S rRNA gene sequencing and subsequent bioinformatic analyses. Community- level substrate utilization is characterized with the BIOLOG EcoPlate.

Results

Fertilizer and rotation treatments significantly affected microbial community structure, while substrate utilization was affected by fertilizer, but not crop-rotation treatments. Differences in relative abundance and occurrence of bacterial taxa found in fertilizer treatments can explain the observed differences in community level substrate utilization.

Conclusion

Long-term fertilization and crop-rotation treatments affect soil microbial community composition and physiology, specifically through chronic nutrient limitation, long-term influx of microbes and organic matter via manure application, as well as through changes in soil chemistry. Relatively greater abundance of Koribacteraceae and Solibacterales taxa in soils might prove useful as indicators of soil degradation.

     

Habitat connectivity and dispersal ability drive the assembly mechanisms of macroinvertebrate communities in river networks

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Detection of Charge-Neutral Near-Equilibrium Processes at Na-Metal Electrodes by Electrochemical Microcalorimetry

Investigations on electrochemical kinetics usually rely on the measurement of current or potential as a function of time. Charge-neutral process steps or side reactions are naturally disguised in the electrical signals and have only indirect impact. However, all processes will contribute to heat evolution. In this work, heat absorption/liberation is measured as a function of time for pulsed Na deposition/dissolution on a Na-electrode in a 1 m NaPF₆/diglyme solution, in addition to the standard electrochemical signals. While potential and current transients both exhibited sharp rectangular shapes, indicating instantaneous electrochemical Na deposition or dissolution on the time scale of the pulse (10 ms), heat absorption or liberation continued up to about 0.5 s after the pulse. Since heat evolution is to large extent reversible, this corresponded to entropy changes in the absence of external electric current flow, pointing to a reversible, charge-neutral chemical process accompanying Na deposition or dissolution. From the observed entropy changes, it is suggested that upon Na deposition solvated Na⁺ ions are instantaneously transferred into the outer layers of the solid electrolyte interphase, followed by slow desolvation.     

Post‐fire understorey regeneration in boreal Pinus sylvestris forest sites with different fire histories

Abstract. We studied the characteristics of understorey regeneration on two sites with different fire history in a mature Pinus sylvestris forest in eastern Finland. The study area was a 4‐ha plot, which was divided into two parts based on fire history analysis. In one part the last fire event was a stand‐replacing fire in the early 19^th century, after which the whole stand regenerated, while the other part of the study plot was subsequently burnt by a surface fire in 1906. Understorey P. sylvestris individuals were much more abundant in the area of the 1906 burn compared to the old burn. In both areas the size frequency distribution of living trees was bimodal, with frequency peaks at the < 5 cm and 30–150 cm height classes. In the old burn small understorey trees were mainly associated with microsites created by treefall disturbances while in the 1906 burn most small understorey trees occurred on vegetation‐covered microsites. This indicates that with increasing time since last fire establishment of new understorey trees becomes more restricted by the availability of microsites created by treefall disturbances. In both areas the proportion of vigorous small understorey trees was highest on decayed wood. In the older burn uprooted pits and mounds also had a significant proportion of healthy small understorey trees, while the majority of trees classified as seriously weakened or dying were growing on microhabitats characterized by undisturbed vegetation. Ripley's K‐function analyses showed that spatial distribution of understorey trees was clustered in both areas in all microsite types and clustering at small scales was most pronounced in understorey trees growing in uprooted spots or in association with decayed wood. The bivariate analysis showed a significant repulsion effect between large trees and understorey trees at intermediate spatial scales, indicating that competition had an effect on understorey tree distribution and this effect was more pronounced in the younger burn. The analysis suggests that in Pinus sylvestris forests the abundance, quality and spatial pattern of understorey tree population may vary considerably as a function of disturbance history.