Effect of a model bovine milk protein, I2-casein, on surface activity of Quillaja bark saponin (QBS) from Sigma was studied at three fluid/fluid interfaces: air/water, tetradecane/water and olive ...oil/water. In all cases, the protein concentration was fixed at 10a6 mol La1, and QBS concentration was varied between 5ADT10a7 and 1ADT10a3 mol La1. Dynamic interfacial tension on the timescale 5 sa3600 s was measured using a drop shape analysis technique. For the air/water system, they were complemented with short-term (50 msa5 s) measurements using a maximum bubble pressure technique. The dynamic results together with the extrapolated equilibrium surface pressures are discussed from the point of view of a complexation between I2-casein and QBS, with the surface activity of the complex changing with its stoichiometry. At low biosurfactant/protein ratios, the interfacial tension at all three interfaces passes through a maximum, corresponding to a transient decrease of both foam and emulsion formation ability. In addition, the effect of QBS on deterioration of I2-casein's surface activity upon ageing at room temperature is discussed.
Drought has promoted large-scale, insect-induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global ...biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under ongoing climate change. Here we propose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: (1) there is a trade-off in tree carbon investment between primary and secondary metabolites (e.g. growth vs defence); (2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and (3) implementing conifer-bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large-scale vegetation models, the under-representation of insect-induced tree mortality.
This open, controlled study evaluated the effects of 6month supplementation with Pycnogenol registered maritime pine bark extract on health risk factors in subjects with metabolic syndrome. ...Pycnogenol registered was used with the aim of improving risk factors associated with metabolic syndrome, central obesity, elevated triglycerides (TG), low HDL cholesterol, high blood pressure and fasting blood glucose. Sixty-four subjects (range 45-55years) presenting with all five risk factors of metabolic syndrome were included, and Pycnogenol registered was administered for 6months. A group of 66 equivalent subjects were followed up as controls. In the 6-month study Pycnogenol registered supplementation 150mg/day decreased waist circumference, TG levels, blood pressure and increased the HDL cholesterol levels in subjects. Pycnogenol lowered fasting glucose from baseline 123 plus or minus 8.6mg/dl to 106.4 plus or minus 5.3 after 3months and to 105.3 plus or minus 2.5 at the end of the study (p<0.05 vs controls). Men's waist circumference decreased with Pycnogenol from 106.2 plus or minus 2.2cm to 98.8 plus or minus 2.3cm and to 98.3 plus or minus 2.1 after 3 and 6months. Women's waist decreased from 90.9 plus or minus 1.6cm to 84.6 plus or minus 2.1cm and to 83.6 plus or minus 2.2cm after 3 and 6months. Both genders waist circumference reduction was significant as compared to controls at both time points. In addition, plasma free radicals decrease in the Pycnogenol group was more effective than in the control group (-34.6%; p<0.05). In conclusion, this study indicates a role for Pycnogenol registered for improving health risk factors in subjects with metabolic syndrome. Copyright copy 2013 John Wiley & Sons, Ltd.
In the eighteenth century, malaria was a prevalent and deadly disease, and the only effective treatment was found in the Andean forests of Spanish America: a medicinal bark harvested from cinchona ...trees that would later give rise to the antimalarial drug quinine. In 1751, the Spanish Crown asserted control over the production and distribution of this medicament by establishing a royal reserve of "fever trees" in Quito. Through this pilot project, the Crown pursued a new vision of imperialism informed by science and invigorated through commerce. But ultimately this project failed, much like the broader imperial reforms that it represented. Drawing on extensive archival research, Matthew Crawford explains why, showing how indigenous healers, laborers, merchants, colonial officials, and creole elites contested European science and thwarted imperial reform by asserting their authority to speak for the natural world.The Andean Wonder Druguses the story of cinchona bark to demonstrate how the imperial politics of knowledge in the Spanish Atlantic ultimately undermined efforts to transform European science into a tool of empire.
Although produced by meristems that are continuous along the stem length, marked differences in bark morphology and in microenvironment would suggest that main stem and twig bark might differ ...ecologically. Here, we examined: (1) how closely associated main stem and twig bark traits were, (2) how these associations varied across sites, and (3) used these associations to infer functional and ecological differences between twig and main stem bark. We measured density, water content, photosynthesis presence/absence, total, outer, inner, and relative thicknesses of main stem and twig bark from 85 species of angiosperms from six sites of contrasting precipitation, temperature, and fire regimes. Density and water content did not differ between main stems and twigs across species and sites. Species with thicker twig bark had disproportionately thicker main stem bark in most sites, but the slope and degree of association varied. Disproportionately thicker main stem bark for a given twig bark thickness in most fire-prone sites suggested stem protection near the ground. The savanna had the opposite trend, suggesting that selection also favors twig protection in these fire-prone habitats. A weak main stem-twig bark thickness association was observed in non fire-prone sites. The near-ubiquity of photosynthesis in twigs highlighted its likely ecological importance; variation in this activity was predicted by outer bark thickness in main stems. It seems that the ecology of twig bark can be generalized to main stem bark, but not for functions depending on the amount of bark, such as protection, storage, or photosynthesis.
Bark thickness is ecologically crucial, affecting functions from fire protection to photosynthesis. Bark thickness scales predictably with stem diameter, but there is little consensus on whether this ...scaling is a passive consequence of growth or an important adaptive phenomenon requiring explanation.
With a comparative study across 913 species, we test the expectation that, if bark thickness–stem diameter scaling is adaptive, it should be possible to find ecological situations in which scaling is predictably altered, in this case between species with different types and deployments of phloem.
‘Dicots’ with successive cambia and monocots, which have phloem-free bark, had predictably thinner inner (mostly living) bark than plants with single cambia. Lianas, which supply large leaf areas with limited stem area, had much thicker inner bark than self-supporting plants. Gymnosperms had thicker outer bark than angiosperms.
Inner bark probably scales with plant metabolic demands, for example with leaf area. Outer bark scales with stem diameter less predictably, probably reflecting diverse adaptive factors; for example, it tends to be thicker in fire-prone species and very thin when bark photosynthesis is favored. Predictable bark thickness–stem diameter scaling across plants with different photosynthate translocation demands and modes strongly supports the idea that this relationship is functionally important and adaptively significant.
Conifers are long-lived organisms, and part of their success is due to their potent defense mechanisms. This review focuses on bark defenses, a front line against organisms trying to reach the ...nutrient-rich phloem. A major breach of the bark can lead to tree death, as evidenced by the millions of trees killed every year by specialized bark-invading insects. Different defense strategies have arisen in conifer lineages, but the general strategy is one of overlapping constitutive mechanical and chemical defenses overlaid with the capacity to up-regulate additional defenses. The defense strategy incorporates a graded response from 'repel', through 'defend' and 'kill', to 'compartmentalize', depending upon the advance of the invading organism. Using a combination of toxic and polymer chemistry, anatomical structures and their placement, and inducible defenses, conifers have evolved bark defense mechanisms that work against a variety of pests. However, these can be overcome by strategies including aggregation pheromones of bark beetles and introduction of virulent phytopathogens. The defense structures and chemicals in conifer bark are reviewed and questions about their coevolution with bark beetles are discussed.
Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to ...kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle's host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Global variation in total bark thickness (TBT) is traditionally attributed to fire. However, bark is multifunctional, as reflected by its inner living and outer dead regions, meaning that, in ...addition to fire protection, other factors probably contribute to TBT variation.
To address how fire, climate, and plant size contribute to variation in TBT, inner bark thickness (IBT) and outer bark thickness (OBT), I sampled 640 species spanning all major angiosperm clades and 18 sites with contrasting precipitation, temperature, and fire regime.
Stem size was by far the main driver of variation in thickness, with environment being less important. IBT was closely correlated with stem diameter, probably for metabolic reasons, and, controlling for size, was thicker in drier and hotter environments, even fire-free ones, probably reflecting its water and photosynthate storage role. OBT was less closely correlated with size, and was thicker in drier, seasonal sites experiencing frequent fires. IBT and OBT covaried loosely and both contributed to overall TBT variation. Thickness variation was higher within than across sites and was evolutionarily labile.
Given high within-site diversity and the multiple selective factors acting on TBT, continued study of the different drivers of variation in bark thickness is crucial to understand bark ecology.
Bark protects the tree against environmental insults. Here, we analyzed whether this defensive strategy could be utilized to broadly enhance protection against colitis. As a proof of concept, we show ...that exosome‐like nanoparticles (MBELNs) derived from edible mulberry bark confer protection against colitis in a mouse model by promoting heat shock protein family A (Hsp70) member 8 (HSPA8)‐mediated activation of the AhR signaling pathway. Activation of this pathway in intestinal epithelial cells leads to the induction of COP9 Constitutive Photomorphogenic Homolog Subunit 8 (COPS8). Utilizing a gut epithelium‐specific knockout of COPS8, we demonstrate that COPS8 acts downstream of the AhR pathway and is required for the protective effect of MBELNs by inducing an array of anti‐microbial peptides. Our results indicate that MBELNs represent an undescribed mode of inter‐kingdom communication in the mammalian intestine through an AhR‐COPS8‐mediated anti‐inflammatory pathway. These data suggest that inflammatory pathways in a microbiota‐enriched intestinal environment are regulated by COPS8 and that edible plant‐derived ELNs may hold the potential as new agents for the prevention and treatment of gut‐related inflammatory disease.
Synopsis
Mulberry bark derived exosome‐like nanoparticles (MBELNs) prevent gut inflammation via plant heat shock protein HSPA8‐mediated activation of AhR/COPS8 pathways. Treatment with MBELNs promotes the restoration of gut microbiome homeostasis, ameliorating intestinal inflammatory pathologies.
Mulberry bark derived exosome‐like nanoparticles (MBELNs) prevent mouse colitis via the AhR/COPS8 pathway.
Binding of MBELN‐derived heat shock protein HSPA8 to AhR leads to the activation of AhR signaling.
Activation of AhR leads to the induction of an array of anti‐microbial peptides (AMPs) via COP9/COPS8.
AhR/COPS8‐dependent induction of AMPs inhibits intestinal inflammation and alters fecal gut microbiota composition.
Mulberry bark derived exosome‐like nanoparticles (MBELNs) prevent gut inflammation via plant heat shock protein HSPA8‐mediated activation of AhR/COPS8 pathways. Treatment with MBELNs promotes the restoration of gut microbiome homeostasis, ameliorating intestinal inflammatory pathologies.
PDF
