Regulationsmechanismen der Ausprägung von Chemotypen in Thymian (Thymus vulgaris)

Das ätherische Öl von Thymianarten hat aufgrund seiner starken antibakteriellen Wirkung vielfältige Anwendungen in der Pharmazie und der Lebensmittelindustrie. Die wertvollsten antibakteriellen Inhaltstoffe des ätherischen Öls, die Monoterpenalkohole Carvacrol und Thymol, werden nur in einigen Kultivaren des Thymians gebildet und unterliegen einer komplizierten genetischen Kontrolle. Wir wollen die Regulation der Terpenproduktion in Thymian mit molekularen Methoden aufklären und die Züchtung von Thymianarten mit genau definiertem Terpengehalt ermöglichen. Stichwörter: Terpensynthese, Monoterpene, Chemotypen, ThymianMechanisms of chemotype formation in thyme (Thymus vulgaris)The essential oil of thyme has a strong antibacterial effect and is utilized in pharmaceutical applications as well as food production. Especially the phenolic monoterpene alcohols thymol and carvacrol are valuable due to their antibacterial, antiseptic and spasmolytical effects. Production of these compounds is subjected to a complex genetic control and found only in some cultivars of thyme. We study the molecular basis of terpene production to elucidate the mechanisms of chemotype formation. Keywords: Terpene biosynthesis, monoterpenes, chemotypes, thym

Localization of sesquiterpene formation and emission in maize leaves after herbivore damage

BACKGROUND: Maize (Zea mays L.) leaves damaged by lepidopteran herbivores emit a complex volatile blend that can attract natural enemies of the herbivores and may also have roles in direct defense and inter- or intra-plant signaling. The volatile blend is dominated by sesquiterpenes of which the majority is produced by two herbivore-induced terpene synthases, TPS10 and TPS23. However, little is known about the pattern of volatile emission within maize leaves. RESULTS: In this study, we restricted herbivore feeding to small sections of the maize leaf with the aim of determining the patterns of volatile sesquiterpene emission throughout the damaged leaf and in neighboring leaves. Sesquiterpene volatiles were released at high rates from damaged leaves, but at much lower rates from neighboring leaves. Release was restricted to the site of damage or to leaf sections located apical to the damage, but was not seen in sections basal to the damage or on the other side of the midrib. The emission pattern correlated well with the transcript pattern of the respective sesquiterpene synthase genes, tps10 and tps23, implying that biosynthesis likely occurs at the site of emission. The concentrations of jasmonic acid and its leucine derivative were also elevated in terpene-emitting tissues suggesting a role for jasmonates in propagating the damage signal. CONCLUSIONS: In contrast to other defense reactions which often occur systemically throughout the whole plant, herbivore-induced sesquiterpene production in maize is restricted to the wounding site and distal leaf parts. Since the signal mediating this reaction is directed to the leaf tip and cannot propagate parallel to the leaf axis, it is likely connected to the xylem. The increasing gradient of volatiles from the tip of the leaf towards the damage site might aid herbivore enemies in host or prey finding

A tandem array of ent-kaurene synthases in maize with roles in gibberellin and more specialized metabolism

While most commonly associated with its role in gibberellin (GA) phytohormone biosynthesis, ent-kaurene also serves as an intermediate in more specialized diterpenoid metabolism, as exemplified by the more than 800 known derived natural products. Among these are the maize kauralexins. However, no ent-kaurene synthases (KSs) have been identified from maize. The maize GA-deficient dwarf-5 (d5) mutant has been associated with a loss of KS activity. The relevant genetic lesion has been previously mapped, and was found here to correlate with the location of the KS-like gene ZmKSL3. Intriguingly, this forms part of a tandem array with two other terpene synthases (TPSs). Although one of these, ZmTPS1, has been previously reported to encode a sesquiterpene synthase, and both ZmTPS1 and that encoded by the third gene, ZmKSL5, have lost the N-terminal γ-domain prototypically associated with KS(L)s, all three genes fall within the KS(L) or TPS-e sub-family. Here it is reported that all three genes encode enzymes that are targeted to the plastid in planta, where diterpenoid biosynthesis is initiated, and which all readily catalyze the production of ent-kaurene. Consistent with the closer phylogenetic relationship of ZmKSL3 with previously identified KSs from cereals, only transcription of this gene is affected in d5 plants. On the other hand, the expression of all three of these genes is inducible, suggesting a role in more specialized metabolism, such as that of the kauralexins. Thus, these results clarify not only gibberellin phytohormone, but also diterpenoid phytoalexin biosynthesis in this important cereal crop plant

Untersuchung der Thymian-Kollektion aus der Bundeszentralen Ex situ- Genbank Gatersleben – Vergleich morphologischer, phytochemischer und molekularer Merkmale

18 Akzessionen der Gaterslebener Thymian-Kollektion aus sieben verschiedenen Arten wurden mit einem standardisierten Boniturschema morphologisch beschrieben. Besonderes Augenmerk lag dabei auf der Anzahl der Drüsenhaare. Außerdem wurden durch Durchflusszytometrie die Genomgröße bestimmt und der Ploidiegrad ermittelt. Die Verwandtschaftsverhältnisse wurden durch ITS-Marker analysiert. Des Weiteren wurde die Zusammensetzung des ätherischen Öls mittels Gaschromatographie gekoppelt an Massenspektrometrie untersucht. Verschiedene Chemotypen konnten dabei gefunden werden. Alle erhobenen Daten werden verglichen und miteinander in Beziehung gesetzt. Stichwörter: Ätherisches Öl, Chemotypen, Drüsenhaare, ITS-Analyse, Thymus spp.Screening of the thyme collection of the federal ex situ genebank in Gatersleben – comparison of morphological, phytochemical and molecular data18 accessions of the Gatersleben thyme collection from seven different species were characterized morphologically with a standardized descriptor. A special focus was on the number of secretory cells. Besides, the genome size was detected with flow cytometry in order to determine the number of chromosomes and the ploidy level. ITS markers were used to analyze the phylogenetic relationship. In addition, the essential oil compounds were studied with gas chromatography coupled with mass spectrometry. Within the 18 accessions different chemotypes could be found. All data will be compared and evaluated. Keywords: Chemotypes, essential oil, ITS analysis, secretory cells, Thymus spp

Next generation breeding tools for chamomile: Evaluating genetic diversity, ploidy variation, and identifying marker-trait associations

Chamomile (Matricaria recutita L.) has a long history of use in herbal medicine with various applications, and the flower heads contain numerous medicinally active compounds. Next generation sequencing (NGS) approaches are applied to exploit genetic resources in the major crop plants to develop genomic resources, and to enhance breeding. Genotyping-by-sequencing (GBS) has been used to evaluate the genetic structure of cultivated populations in the non-model crop chamomile using 6495 SNP markers, and to perform a genome wide association study (GWAS) identifying sequences significantly associated with the medicinally important alpha-bisabolol content. Ploidy variation in chamomile was investigated by high-throughput flow-cytometry. Di-, tri- and tetraploid plants were identified, and in field trials characterized. Since seeds are not needed in the harvested product of chamomile, triploidy could be a way to obtain a sterile chamomile variety, omitting the problems of chamomile seeds lying up to 15 years dormant in the soil and facilitating crop rotation in the fields.Die Nutzung von Kamille (Matricaria recutita L.) als Arzneipflanze hat eine lange Tradition und umfasst einen weiten Anwendungsbereich. Die Blütenköpfe von Kamille enthalten eine Vielzahl an medizinisch wirksamen Inhaltsstoffen. Next-Generation Sequenzierungsmethoden (NGS) werden bei den Hauptkulturpflanzen verwendet, um genetische Ressourcen zu erschließen und die Züchtung zu unterstützen. Genotypisierungdurch- Sequenzierung (GBS) wurde bei der Nicht-Modellpflanze Kamille zur Charakterisierung der genetischen Diversität angewandt. Unter Nutzung von den erhaltenen 6495 hochqualitativen SNP-Markern wurden mittels einer genomweiten Assoziationsstudie (GWAS) DNA-Sequenzen identifiziert, die signifikant mit dem pharmazeutisch wichtigen Alpha-Bisabolol-Gehalt assoziiert sind. Die Ploidievariation in der Art Echte Kamille wurde mittels Hochdurchsatz-Durchflusszytometrie untersucht. Di-, tri- und tetraploide Pflanzen wurden identifiziert und in Feldversuchen charakterisiert. Da für das Ernteprodukt bei Kamille keine Samen benötigt werden, könnte Triploidie ein Weg sein, eine sterile Kamillensorte zu erzeugen. Mit einer sterilen Sorte könnte so das Problem gelöst werden, dass Kamillensamen im Boden bis zu 15 Jahre lang nach dem Anbau auskeimen, was den Fruchtwechsel auf den Ackerböden erheblich erschwert und u.a. zur Akkumulation von Kamillenkrankheiten führt

Hospitalized patients dying with SARS-CoV-2 infection—an analysis of patient characteristics and management in ICU and general ward of the LEOSS registry

BACKGROUND: COVID-19 is a severe disease with a high need for intensive care treatment and a high mortality rate in hospitalized patients. The objective of this study was to describe and compare the clinical characteristics and the management of patients dying with SARS-CoV-2 infection in the acute medical and intensive care setting. METHODS: Descriptive analysis of dying patients enrolled in the Lean European Open Survey on SARS-CoV-2 Infected Patients (LEOSS), a non-interventional cohort study, between March 18 and November 18, 2020. Symptoms, comorbidities and management of patients, including palliative care involvement, were compared between general ward and intensive care unit (ICU) by univariate analysis. RESULTS: 580/4310 (13%) SARS-CoV-2 infected patients died. Among 580 patients 67% were treated on ICU and 33% on a general ward. The spectrum of comorbidities and symptoms was broad with more comorbidities (≥ four comorbidities: 52% versus 25%) and a higher age distribution (>65 years: 98% versus 70%) in patients on the general ward. 69% of patients were in an at least complicated phase at diagnosis of the SARS-CoV-2 infection with a higher proportion of patients in a critical phase or dying the day of diagnosis treated on ICU (36% versus 11%). While most patients admitted to ICU came from home (71%), patients treated on the general ward came likewise from home and nursing home (44% respectively) and were more frequently on palliative care before admission (29% versus 7%). A palliative care team was involved in dying patients in 15%. Personal contacts were limited but more often documented in patients treated on ICU (68% versus 47%). CONCLUSION: Patients dying with SARS-CoV-2 infection suffer from high symptom burden and often deteriorate early with a demand for ICU treatment. Therefor a demand for palliative care expertise with early involvement seems to exist

Covid-19 triage in the emergency department 2.0: how analytics and AI transform a human-made algorithm for the prediction of clinical pathways

The Covid-19 pandemic has pushed many hospitals to their capacity limits. Therefore, a triage of patients has been discussed controversially primarily through an ethical perspective. The term triage contains many aspects such as urgency of treatment, severity of the disease and pre-existing conditions, access to critical care, or the classification of patients regarding subsequent clinical pathways starting from the emergency department. The determination of the pathways is important not only for patient care, but also for capacity planning in hospitals. We examine the performance of a human-made triage algorithm for clinical pathways which is considered a guideline for emergency departments in Germany based on a large multicenter dataset with over 4,000 European Covid-19 patients from the LEOSS registry. We find an accuracy of 28 percent and approximately 15 percent sensitivity for the ward class. The results serve as a benchmark for our extensions including an additional category of palliative care as a new label, analytics, AI, XAI, and interactive techniques. We find significant potential of analytics and AI in Covid-19 triage regarding accuracy, sensitivity, and other performance metrics whilst our interactive human-AI algorithm shows superior performance with approximately 73 percent accuracy and up to 76 percent sensitivity. The results are independent of the data preparation process regarding the imputation of missing values or grouping of comorbidities. In addition, we find that the consideration of an additional label palliative care does not improve the results