Trichomes in plant-herbivore interactions: the first line of defense of the wild tobacco Nicotiana attenuata against attacking insects

Trichomes represent a first meal for neonate larvae of the tobacco hornworm Manduca sexta and we explored the functions of their exudates and contents in terms of plant defense. We analyzed the composition of O-acyl sugars in Nicotiana attenuata and demonstrated that their mixture is even more complex than previously described. Fractionation of crude plant extracts and subsequent HPLC-ToFMS analysis revealed the presence of at least 15 different compounds. In addition, MS2 experiments showed that O-acyl sugars can be classified into three different structural classes and that different O-acyl sugar classes vary in their substitution pattern of the sucrose core molecule. We could demonstrate that O-acyl sugars containing trichome exudates are consumed by the larvae of Manduca sexta and thereby cause a release of branched chain aliphatic acids from either the larval frass or body. Furthermore we could show that these volatile acids in M. sexta’s body odor are utilized by the omnivorous ant Pogonomyrmex rugosus to locate its prey and forage on M. sexta. In addition to these findings we could demonstrate that not only omnivorous ants but most likely lizards also use M. sexta’s body and frass odor to locate their prey. Further studies of plant trichomes led to the identification of a trichome metabolite novel to the Solanaceae. Comparative NMR- and MS studies revealed the presence of phaseoloidin - a homogentisic acid glucoside - in the trichomes of the wild tobacco N. attenuata. We could show that besides O-acyl sugars, phaseoloidin and nicotine are present in the different trichome types of N. attenuata and that their abundance varies between different trichome parts. In addition we could demonstrate that phaseoloidin negatively affects the growth of specialist Manduca sexta and generalist Spodoptera littoralis larvae. These results underline the important defensive function of trichomes and their exudates in nature

Reliability of Intra-Retinal Layer Thickness Estimates

Purpose Measurement of intra-retinal layer thickness using optical coherence tomography (OCT) has become increasingly prominent in multiple sclerosis (MS) research. Nevertheless, the approaches used for determining the mean layer thicknesses vary greatly. Insufficient data exist on the reliability of different thickness estimates, which is crucial for their application in clinical studies. This study addresses this lack by evaluating the repeatability of different thickness estimates. Methods Studies that used intra-retinal layer segmentation of macular OCT scans in patients with MS were retrieved from PubMed. To investigate the repeatability of previously applied layer estimation approaches, we generated datasets of repeating measurements of 15 healthy subjects and 13 multiple sclerosis patients using two OCT devices (Cirrus HD-OCT and Spectralis SD-OCT). We calculated each thickness estimate in each repeated session and analyzed repeatability using intra-class correlation coefficients and coefficients of repeatability. Results We identified 27 articles, eleven of them used the Spectralis SD-OCT, nine Cirrus HD-OCT, two studies used both devices and two studies applied RTVue-100. Topcon OCT-1000, Stratus OCT and a research device were used in one study each. In the studies that used the Spectralis, ten different thickness estimates were identified, while thickness estimates of the Cirrus OCT were based on two different scan settings. In the simulation dataset, thickness estimates averaging larger areas showed an excellent repeatability for all retinal layers except the outer plexiform layer (OPL). Conclusions Given the good reliability, the thickness estimate of the 6mm-diameter area around the fovea should be favored when OCT is used in clinical research. Assessment of the OPL was weak in general and needs further investigation before OPL thickness can be used as a reliable parameter

Dirac cones in two-dimensional borane

We introduce two-dimensional borane, a single-layered material of BH stoichiometry, with promising electronic properties. We show that, according to Density Functional Theory calculations, two-dimensional borane is semimetallic, with two symmetry-related Dirac cones meeting right at the Fermi energy $E_f$. The curvature of the cones is lower than in graphene, thus closer to the ideal linear dispersion. Its structure, formed by a puckered trigonal boron network with hydrogen atoms connected to each boron atom, can be understood as distorted, hydrogenated borophene (Science \textbf{350}, 1513 (2015)). Chemical bonding analysis reveals the boron layer in the network being bound by delocalized four-center two-electron ${\sigma}$ bonds. Finally, we suggest high-pressure could be a feasible route to synthesise two-dimensional borane.Comment: 5 pages, 3 figures, 1 tabl

Tree species richness differentially affects the chemical composition of leaves, roots and root exudates in four subtropical tree species

Plants produce thousands of compounds, collectively called the metabolome, which mediate interactions with other organisms. The metabolome of an individual plant may change according to the number and nature of these interactions. We tested the hypothesis that tree diversity level affects the metabolome of four subtropical tree species in a biodiversity–ecosystem functioning experiment, BEF‐China. We postulated that the chemical diversity of leaves, roots and root exudates increases with tree diversity. We expected that the strength of this diversity effect differs among leaf, root and root exudates samples. Considering their role in plant competition, we expected to find the strongest effects in root exudates. Roots, root exudates and leaves of four tree species ( Cinnamomum camphora , Cyclobalanopsis glauca , Daphniphyllum oldhamii and Schima superba ) were sampled from selected plots in BEF‐China. The exudate metabolomes were normalized over their non‐purgeable organic carbon level. Multivariate analyses were applied to identify the effect of both neighbouring (local) trees and plot diversity on tree metabolomes. The species‐ and sample‐specific metabolites were assigned to major compound classes using the ClassyFire tool, whereas potential metabolites related to diversity effects were annotated manually. Individual tree species showed distinct leaf, root and root exudate metabolomes. The main compound class in leaves was the flavonoids, whereas carboxylic acids, prenol lipids and specific alkaloids were most prominent in root exudates and roots. Overall, plot diversity had a stronger effect on metabolome profiles than the local diversity. Leaf metabolomes responded more often to tree diversity level than exudates, whereas root metabolomes varied the least. We found no uniform or general pattern of alterations in metabolite richness or diversity in response to variation in tree diversity. The response differed among species and tissues. Synthesis . Classification of metabolites supported initial ecological interpretation of differences among species and organs. Particularly, the metabolomes of leaves and root exudates respond to differences in tree diversity. These responses were neither linear nor uniform and individual metabolites showed different dynamics. More controlled interaction experiments are needed to dissect the causes and consequences of the observed shifts in plant metabolomes

Selective inhibition of neurogenic, but not agonist‐induced contractions by phospholipase A2 inhibitors points to presynaptic phospholipase A2 functions in contractile neurotransmission to human prostate smooth muscle

Background Phospholipases A2 (PLA2) may be involved in α1-adrenergic contraction by formation of thromboxane A2 in different smooth muscle types. However, whether this mechanism occurs with α1-adrenergic contractions of the prostate, is still unknown. While α1-adrenoceptor antagonists are the first line option for medical treatment of voiding symptoms in benign prostatic hyperplasia (BPH), improvements are limited, probably by nonadrenergic contractions including thromboxane A2. Here, we examined effects of PLA2 inhibitors on contractions of human prostate tissues. Methods Prostate tissues were obtained from radical prostatectomy. Contractions were induced by electric field stimulation (EFS) and by α1-adrenergic agonists in an organ bath, after application of the cytosolic PLA2 inhibitors ASB14780 and AACOCF3, the secretory PLA2 inhibitor YM26734, the leukotriene receptor antagonist montelukast, or of solvent to controls. Results Frequency-dependent contractions of human prostate tissues induced by EFS were inhibited by 25% at 8 Hz, 38% at 16 Hz and 37% at 32 Hz by ASB14780 (1 µM), and by 32% at 16 Hz and 22% at 32 Hz by AACOCF3 (10 µM). None of both inhibitors affected contractions induced by noradrenaline, phenylephrine or methoxamine. YM26734 (3 µM) and montelukast (0.3 and 1 µM) neither affected EFS-induced contractions, nor contractions by α1-adrenergic agonists, while all contractions were substantially inhibited by silodosin (100 nM). Conclusions Our findings suggest presynaptic PLA2 functions in prostate smooth muscle contraction, while contractions induced by α1-adrenergic agonists occur PLA2-independent. Lacking sensitivity to montelukast excludes an involvement of PLA2-derived leukotrienes in promotion of contractile neurotransmission

Soil chemical legacies trigger species‐specific and context‐dependent root responses in later arriving plants

Abstract Soil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation and functional traits of a forb ( Dianthus deltoides ) and a grass species ( Festuca rubra ). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect on F . rubra , root foraging by D . deltoides decreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D . deltoides arose via either a root growth‐dependent pathway (forb metabolome) or a root trait‐dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants

In vivo

Background: Tendon mechanical properties have been used to evaluate the effects of therapies on the healing of animal tendons, but these measures have not been convenient to record in vivo in humans due to their invasive nature. The aims of this study were to assess the capability of an ultrasonography technique to track the change in stiffness of the healing human patellar tendon and to assess the correlation between stiffness parameters and clinical recovery measurements

A mosaic of induced and non-induced branches promotes variation in leaf traits, predation and insect herbivore assemblages in canopy trees

Forest canopies are complex and highly diverse environments. Their diversity is affected by pronounced gradients in abiotic and biotic conditions, including variation in leaf chemistry. We hypothesised that branch-localised defence induction and vertical stratification in mature oaks constitute sources of chemical variation that extend across trophic levels. To test this, we combined manipulation of plant defences, predation monitoring, food-choice trials with herbivores and sampling of herbivore assemblages. Both induction and vertical stratification affected branch chemistry, but the effect of induction was stronger. Induction increased predation in the canopy and reduced herbivory in bioassays. The effects of increased predation affected herbivore assemblages by decreasing their abundance, and indirectly, their richness. In turn, we show that there are multiple factors contributing to variation across canopies. Branch-localised induction, variation between tree individuals and predation may be the ones with particularly strong effects on diverse assemblages of insects in temperate forests

Oncological impact of perioperative blood transfusion in bladder cancer patients undergoing radical cystectomy: Do we need to consider storage time of blood units, donor age, or gender matching?

Background The oncological impact of perioperative blood transfusions (PBTs) of patients undergoing radical cystectomy (RC) because of bladder cancer (BCa) has been a controversial topic discussed in recent years. The main cause for the contradictory findings of existing studies might be the missing consideration of the storage time of red blood cell units (BUs), donor age, and gender matching. Study Design and Methods We retrospectively analyzed BCa patients who underwent RC in our department between 2004 and 2021. We excluded patients receiving BUs before RC, >10 BUs, or RC in a palliative setting. We assessed the effect of blood donor characteristics and storage time on overall survival (OS) and cancer-specific survival (CSS) through univariate and multivariable Cox regression analysis. We also performed a propensity score matching with patients who received BUs and patients who did not on a 1:1 ratio. Results We screened 1692 patients and included 676 patients for the propensity score matching. In the multivariable analysis, PBT was independently associated with worse OS and CSS (p < .001). Postoperative transfusions were associated with better OS (p = .004) and CSS (p = .008) compared to intraoperative or mixed transfusions. However, there was no influence of blood donor age, storage time, or gender matching on prognosis. Discussion In our study of BCa patients undergoing RC, we demonstrate that PBT, especially if administered intraoperatively, is an independent risk factor for a worse prognosis. However, storage time, donor age, or gender matching did not negatively affect oncological outcomes. Therefore, the specific selection of blood products does not promise any benefits