Volatile compounds-the language of all kingdoms?

Volatile organic compounds (VOCs) were originally identified as communication compounds between plants and insects. Today, we know that VOCs are released by organisms of all kingdoms, including bacteria and fungi, and mediate diverse intra- and interspecific interactions both above- and below-ground. Following recent trends in this research field, the majority of reviews and research papers in this special issue focus on possible biological and ecological functions and various other aspects of microbial VOCs (mVOCs). Additional reviews and research papers highlight connections between microbe-induced plant VOCs, and their possible application in future sustainable crop protection strategies

Volatile terpenes - mediators of plant-to-plant communication.

Plants interact with other organisms employing volatile organic compounds (VOCs). The largest group of plant-released VOCs are terpenes, comprised of isoprene, monoterpenes and sesquiterpenes. Mono- and sesquiterpenes are well known communication compounds in plant-insect interactions whereas the smallest, most commonly emitted terpene, isoprene, is rather assigned a function in combating abiotic stresses. Recently, it has become evident that different volatile terpenes also act as plant-to-plant signaling cues. Upon being perceived, specific volatile terpenes can sensitize distinct signaling pathways in receiver plant cells, which in turn trigger plant innate immune responses. This vastly extends the range of action of volatile terpenes that not only protect plants from various biotic and abiotic stresses, but also convey information about environmental constraints within and between plants. As a result, plant-insect and plant-pathogen interactions, which are believed to influence each other through phytohormone cross talk, are likely equally sensitive to reciprocal regulation via volatile terpene cues. Here, we review the current knowledge of terpenes as volatile semiochemicals and discuss why and how volatile terpenes make good signaling cues. We discuss how volatile terpenes may be perceived by plants, what are possible downstream signaling events in receiver plants, and how responses to different terpene cues might interact to orchestrate the net plant response to multiple stresses. Finally, we discuss how the signal can be further transmitted to the community level leading to a mutually beneficial community scale response or distinct signaling with near kin

High glucose enhances thrombin responses via protease-activated receptor-4 in human vascular smooth muscle cells

Diabetes is associated with vascular remodeling and increased thrombin generation. Thrombin promotes vascular smooth muscle cell (SMC) mitogenesis and migration via protease-activated receptors (PAR)-1, PAR-3, and PAR-4. We investigated the effect of high glucose on expression and function of vascular thrombin receptors.In human vascular SMCs, high glucose (25 versus 5.5 mmol/L) induced a rapid and sustained increase in PAR-4 mRNA, protein, and cell surface expression. PAR-1 and PAR-3 expression were not changed. High glucose pretreatment (48 hours) enhanced thrombin or PAR-4-activating peptide but not PAR-1-activating peptide evoked intracellular calcium mobilization, migration, and tumor necrosis factor α gene expression. This enhancement of thrombin-stimulated migration and gene expression by high glucose was abolished by endogenous PAR-4 knockdown. PAR-4 regulation was prevented by inhibition of protein kinase (PK)C-β and -δ isoforms or nuclear factor (NF)κB. Nuclear translocation of NFκB in high glucose-stimulated SMCs led to PKC-dependent NFκB binding to the PAR-4 promoter in a chromatin immunoprecipitation assay. Furthermore, in situ hybridization and immunohistochemistry confirmed high abundance of PAR-4 in human diabetic vessels as compared with nondiabetic vessels.High glucose enhances SMC responsiveness to thrombin through transcriptional upregulation of PAR-4, mediated via PKC-β, -δ, and NFκB. This may play an important role in the vascular complications of diabetes

Isoprene and β-caryophyllene confer plant resistance via different plant internal signaling pathways.

Isoprene and other terpenoids are important biogenic volatile organic compounds in terms of atmospheric chemistry. Isoprene can aid plant performance under abiotic stresses, but the fundamental biological reasons for the high emissions are not completely understood. Here, we provide evidence of a previously unrecognized ecological function for isoprene and for the sesquiterpene, ß-caryophyllene. We show that isoprene and ß-caryophyllene act as core components of plant signaling networks, inducing resistance against microbial pathogens in neighboring plants. We challenged Arabidopsis thaliana with Pseudomonas syringae, after exposure to pure volatile terpenoids or to volatile emissions of transformed poplar or Arabidopsis plants. The data suggests that isoprene induces a defense response in receiver plants that is similar to that elicited by monoterpenes and depended on salicylic acid (SA) signaling. In contrast, the sesquiterpene, ß-caryophyllene, induced resistance via jasmonic acid (JA)-signaling. The experiments in an open environment show that natural biological emissions are enough to induce resistance in neighboring Arabidopsis. Our results show that both isoprene and ß-caryophyllene function as allelochemical components in complex plant signaling networks. Knowledge of this system may be used to boost plant immunity against microbial pathogens in various crop management schemes

Visual function resists early neurodegeneration in the visual system in primary progressive multiple sclerosis

BACKGROUND: Neurodegeneration in multiple sclerosis (MS) affects the visual system but dynamics and pathomechanisms over several years especially in primary progressive MS (PPMS) are not fully understood. METHODS: We assessed longitudinal changes in visual function, retinal neurodegeneration using optical coherence tomography, MRI and serum NfL (sNfL) levels in a prospective PPMS cohort and matched healthy controls. We investigated the changes over time, correlations between outcomes and with loss of visual function. RESULTS: We followed 81 patients with PPMS (mean disease duration 5.9 years) over 2.7 years on average. Retinal nerve fibre layer thickness (RNFL) was reduced in comparison with controls (90.1 vs 97.8 µm; p<0.001). Visual function quantified by the area under the log contrast sensitivity function (AULCSF) remained stable over a continuous loss of RNFL (0.46 µm/year, 95% CI 0.10 to 0.82; p=0.015) up until a mean turning point of 91 µm from which the AULCSF deteriorated. Intereye RNFL asymmetry above 6 µm, suggestive of subclinical optic neuritis, occurred in 15 patients and was related to lower AULCSF but occurred also in 5 out of 44 controls. Patients with an AULCSF progression had a faster increase in Expanded Disability Status Scale (beta=0.17/year, p=0.043). sNfL levels were elevated in patients (12.2 pg/mL vs 8.0 pg/mL, p<0.001), but remained stable during follow-up (beta=-0.14 pg/mL/year, p=0.291) and were not associated with other outcomes. CONCLUSION: Whereas neurodegeneration in the anterior visual system is already present at onset, visual function is not impaired until a certain turning point. sNfL is not correlated with structural or functional impairment in the visual system

CO2 pressure broadening and shift coefficients for the 2–0 band of 12C16O

Fourier transform absorption spectra of the 2–0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO2 pressure-induced line broadening and line shift coefficients, and the temperature dependence of the former have been measured including line mixing using a multi-spectrum non-linear least squares fitting technique. Different line shape models have been considered to take into account the Dicke narrowing or speed dependence effects. Measured line-shape parameters were compared with theoretical values, calculated for individual temperatures using a semi-empirical method and the Exponential Power Gap (EPG) law.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Chronic thromboembolic pulmonary hypertension and impairment after pulmonary embolism: the FOCUS study

Aims: To systematically assess late outcomes of acute pulmonary embolism (PE) and to investigate the clinical implications of post-PE impairment (PPEI) fulfilling prospectively defined criteria. Methods and results: A prospective multicentre observational cohort study was conducted in 17 large-volume centres across Germany. Adult consecutive patients with confirmed acute symptomatic PE were followed with a standardized assessment plan and pre-defined visits at 3, 12, and 24 months. The co-primary outcomes were (i) diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), and (ii) PPEI, a combination of persistent or worsening clinical, functional, biochemical, and imaging parameters during follow-up. A total of 1017 patients (45% women, median age 64 years) were included in the primary analysis. They were followed for a median duration of 732 days after PE diagnosis. The CTEPH was diagnosed in 16 (1.6%) patients, after a median of 129 days; the estimated 2-year cumulative incidence was 2.3% (1.2-4.4%). Overall, 880 patients were evaluable for PPEI; the 2-year cumulative incidence was 16.0% (95% confidence interval 12.8-20.8%). The PPEI helped to identify 15 of the 16 patients diagnosed with CTEPH during follow-up (hazard ratio for CTEPH vs. no CTEPH 393; 95% confidence interval 73-2119). Patients with PPEI had a higher risk of re-hospitalization and death as well as worse quality of life compared with those without PPEI. Conclusion: In this prospective study, the cumulative 2-year incidence of CTEPH was 2.3%, but PPEI diagnosed by standardized criteria was frequent. Our findings support systematic follow-up of patients after acute PE and may help to optimize guideline recommendations and algorithms for post-PE care.Thrombosis and Hemostasi

Chronic thromboembolic pulmonary hypertension and impairment after pulmonary embolism: the FOCUS study

Aims To systematically assess late outcomes of acute pulmonary embolism (PE) and to investigate the clinical implications of post-PE impairment (PPEI) fulfilling prospectively defined criteria. Methods and results A prospective multicentre observational cohort study was conducted in 17 large-volume centres across Germany. Adult consecutive patients with confirmed acute symptomatic PE were followed with a standardized assessment plan and pre-defined visits at 3, 12, and 24 months. The co-primary outcomes were (i) diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), and (ii) PPEI, a combination of persistent or worsening clinical, functional, biochemical, and imaging parameters during follow-up. A total of 1017 patients (45% women, median age 64 years) were included in the primary analysis. They were followed for a median duration of 732 days after PE diagnosis. The CTEPH was diagnosed in 16 (1.6%) patients, after a median of 129 days; the estimated 2-year cumulative incidence was 2.3% (1.2-4.4%). Overall, 880 patients were evaluable for PPEI; the 2-year cumulative incidence was 16.0% (95% confidence interval 12.8-20.8%). The PPEI helped to identify 15 of the 16 patients diagnosed with CTEPH during follow-up (hazard ratio for CTEPH vs. no CTEPH 393; 95% confidence interval 73-2119). Patients with PPEI had a higher risk of re-hospitalization and death as well as worse quality of life compared with those without PPEI. Conclusion In this prospective study, the cumulative 2-year incidence of CTEPH was 2.3%, but PPEI diagnosed by standardized criteria was frequent. Our findings support systematic follow-up of patients after acute PE and may help to optimize guideline recommendations and algorithms for post-PE care