Institut für Biologie

Permanent URI for this collectionhttps://hohpublica.uni-hohenheim.de/handle/123456789/81

Browse

Now showing 1 - 20 of 190

Radial stem growth response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to severe drought depending on soil properties and rooting characteristics
(2024) Spangenberg, Göran; Hein, Sebastian
The increase in severe droughts and heat waves caused by climate change has impacted forests worldwide. One of these effects is the increase in drought-related damage to trees and tree dieback in many regions of the world. This became visible in Central Europe during and after the extreme drought of 2018. Not only severely damaged forests but many still existing forests must also be adapted to the changing climate. In this forest conversion, the adaptation of tree species composition to the changing climatic conditions, e.g., by planting other tree species, is an important measure. Drought tolerance is among the most important criteria for tree species selection. In this context, the planting of non-native tree species that are considered drought tolerant is an increasingly used silvicultural strategy. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), which is native to North America, is an important substitute tree species with a higher drought tolerance, especially compared to Norway spruce (Picea abies (L.) Karst.), which has experienced severe drought damage in different regions of Europe. However, there has also been an increase in drought-related problems with Douglas-fir in some regions of Europe and North America. There is a need for research on the influence of site and rooting characteristics on the drought tolerance of this tree species. The objective of this dissertation was to investigate the influence of two soil properties (soil texture and plant-available water capacity) and two rooting characteristics (effective rooting depth and fine root density at a 0–40 cm soil depth) on the drought tolerance of Douglas-fir during the extreme drought year 2018. Different indicators derived from measurements of radial stem growth and stem radius changes were used to assess drought tolerance. Seven study sites were selected along a soil texture gradient from sand to clay. To investigate the influence of soil and rooting characteristics, other influencing factors on the drought tolerance of Douglas-fir were kept as consistent as possible. For this purpose, the study sites were selected in close proximity in southern Germany, at an elevation of approximately 500m a.s.l. Since the variety and provenance of Douglas-fir also influence drought tolerance, genetic origin analysis was carried out. As a result, all trees examined were clearly assigned to the coastal variety. They originated from the central area of the natural distribution range of the coastal variety. The soil physical and rooting characteristics were determined on a representative soil profile for each of the seven sites. In the investigations in Chapter II, cores were collected from Douglas-fir trees with an increment borer and tree ring widths were measured. The growth response indices of resistance, recovery, and resilience were derived from this as indicators of drought tolerance. These indices quantify the ability of trees to maintain stem growth during drought stress events and stem growth recovery after drought. In the study in Chapter III, stem radius changes were measured using dendrometers with high temporal and spatial resolution at the same study sites. Based on these data, the water status parameters maximum daily shrinkage and tree water deficit were derived for two pronounced drought periods in the extreme drought year 2018. In addition, growth onset and cessation for 2018 were estimated from dendrometer measurements and compared with the corresponding values for years with more precipitation, 2017 and 2019. Linear mixed-effects models were used to analyze the influence of soil and rooting characteristics on the indicators of drought tolerance and water status in Douglas-fir. The following overall conclusions can be drawn from the results of both studies. In general, Douglas-fir showed a higher drought tolerance on silty and sandy soils. On clay-dominated soils, a higher risk of drought stress is to be expected during very severe drought. A higher plant-available water capacity only reduced drought stress in Douglas-fir at the initial stage of the extreme drought in 2018. In the advanced stage of drought, this positive effect was no longer observed. A greater rooting depth reduced drought stress in the later stage of extreme drought and proved to be an influencing factor that improved drought tolerance in the analysis of the interannual radial growth. Douglas-fir trees only benefited from more intensive rooting in the top 40 cm of soil in the initial stage of extreme drought. In the later drought stage, no significant influence was detected. Based on measurement of the interannual radial stem growth and intra-annual stem radius changes, this drought stress study provides recommendations for Douglas-fir cultivation under the predicted climatic changes with an increased occurrence of severe drought periods. The combined application of the two measurement methods reduced method-specific uncertainties and answered additional research questions. There are comparatively few studies on the drought tolerance of trees that examine the relationships between soil properties, rooting characteristics, and aboveground tree responses to drought. This investigation shows the importance of such studies in understanding the response patterns of trees to very severe drought events.
Effects of feeding diets without mineral P supplement on intestinal phytate degradation, blood concentrations of Ca and P, and excretion of Ca and P in two laying hen strains before and after onset of laying activity
(2024) Sommerfeld, Vera; Bennewitz, Jörn; Camarinha-Silva, Amélia; Feger, Martina; Föller, Michael; Huber, Korinna; Oster, Michael; Ponsuksili, Siriluck; Schmucker, Sonja; Seifert, Jana; Stefanski, Volker; Wimmers, Klaus; Rodehutscord, Markus
The objective of this study was to characterize intestinal phytate degradation and mineral utilization by 2 laying hen strains before and after the onset of egg laying using diets without or with a mineral phosphorus (P) supplement. One offspring of 10 roosters per strain (Lohmann Brown-classic [LB] and Lohmann LSL-classic [LSL]) was sacrificed before (wk 19) and after (wk 24) the onset of egg-laying activity and following 4 wk placement in a metabolic unit. Diets were corn-soybean meal-based and without supplemented P (P-) or with 1 g/kg supplemented P (P+) from monocalcium phosphate. In wk 19 and 24, the blood plasma and digesta of duodenum+jejunum and distal ileum were collected. The concentration of P in blood plasma was higher in hens fed P+ than P- (P < 0.001). In duodenum + jejunum and ileum content, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in P- than in P+ (P ≤ 0.009). In duodenum+jejunum, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in wk 24 than 19 and lower in LSL than LB hens (P < 0.001). The concentration of myo-inositol (MI) in duodenum + jejunum content was lower in wk 19 than 24 (P < 0.001). Following a 4-d total excreta collection, the retained amount of P was higher in P+ than P- (P < 0.001). Phosphorus retention was lower in LB hens fed P- than in other treatments (P × strain: P = 0.039). In the jejunal tissue, some genes related to intracellular InsP metabolism were higher expressed in LB than LSL hens. The renunciation of mineral P increased endogenous phytate degradation, but more P was retained with supplemented P. Differences in endogenous phytate degradation between the periods before and after the onset of egg laying might be attributed to different Ca concentrations in intestinal digesta caused by different Ca needs in both periods.
Effects of myo-inositol supplementation in the diet on myo-inositol concentrations in the intestine, blood, eggs, and excreta of laying hens
(2025) Sommerfeld, Vera; Hanauska, Anna; Huber, Korinna; Bennewitz, Jörn; Camarinha-Silva, Amélia; Feger, Martina; Föller, Michael; Oster, Michael; Ponsuksili, Siriluck; Schmucker, Sonja; Seifert, Jana; Stefanski, Volker; Wimmers, Klaus; Rodehutscord, Markus
The objectives of this study were to investigate whether an increased dietary myo-inositol (MI) supply translates into changes in MI concentrations and endogenous mucosal phosphatase activities in the intestine of laying hens and whether different laying hen strains respond differently to MI supplementation. The diets were corn–soybean meal-based and supplemented without (MI0) or with 1 (MI1), 2 (MI2), or 3 (MI3) g MI/kg feed. Ten hens per strain (Lohmann Brown-classic (LB) and Lohmann LSL-classic (LSL)) and diet were sacrificed at the age of 30 wk following a 4-wk stay in a metabolic unit. The blood plasma, digesta of the duodenum+jejunum and distal ileum, mucosa of the duodenum, and eggs were collected at wk 30. The concentration of MI in the blood plasma was increased by MI supplementation (P < 0.001); however, that of MI3 did not further increase compared with MI2. The concentration of MI in the duodenum+jejunum and ileum increased steadily (P < 0.001). The MI concentration in the duodenum+jejunum was higher in LB than in LSL hens (P = 0.017). The MI concentration in egg yolk was increased by MI supplementation (P < 0.001) and was higher in LB than in LSL hens (P = 0.015). Strain or diet did not affect mucosal phosphatase activity. Myo-inositol flow at the terminal ileum and postileal disappearance increased with each increment in MI supplementation (P < 0.001) and was higher in LB than in LSL hens (P ≤ 0.041). Regression analysis indicated that, on average, 84% of supplemented MI was retained in the body or metabolized and excreted in a different form. Based on the measured MI concentrations in the blood and eggs, dietary MI was not completely absorbed in the small intestine and, to a different extent, in the two laying hen strains. A higher dietary MI supply was followed by higher intestinal absorption or metabolism by microorganisms. The fate of supplemented MI and its relevance to birds warrant further research.
Ontogeny and reproductive paleobiology in the Mesozoic marine reptile clade Ichthyosauria
(2023) Miedema, Feiko; Schoch, Rainer
Ichthyosaurs were viviparous marine reptiles that occupied many consumer niches in the marine ecosystems of the Mesozoic. Their viviparous reproductive strategy lends us the opportunity to study their prenatal development in great detail and lets us assess their birthing strategies. Moreover, some species are common in Lagerstätten deposits, which means we are likewise able to assess postnatal ontogeny. The assessment of ontogeny is important in our understanding of an extinct animal’s paleobiology and necessary for its’ correct phylogenetic placement. After studying the prenatal osteological development in the ichthyosaur Stenopterygius we now recognize 4 different stages on the basis of relative cranial ossification. The overall ossification sequence was very similar to other diapsids. The establishment of multiple prenatal stages was a first for an extinct sauropsid. We likewise erected 3 postnatal stages in Stenopterygius on the basis of cranial ossification, fusion and element morphology. Recognizing multiple postnatal ontogenetic stages in model (fossil) organism such as Stenopterygius will help recognize the ontogenetic stages of less well-known species and single specimens as well as refine phylogenetic characters which may be prone to major ontogenetic differences. Moreover, the cranial ossification and ontogeny of Mixosaurus cornalianus was studied. Due to sample size and the difficult crushed material, we were unable to establish the same stages as in Stenopterygius. However, we did clarify certain parts in Mixosaurus osteology, established some ontogenetically variable traits, most notably regarding the braincase and lower jaw, and were able to assess in detail a prenatal stage. Early cranial development in Mixosaurus differs from that of Stenopterygius regarding the precise ossification of the basioccipital and exoccipital, whereby Mixosaurus possibly shows a more ancestral developmental pathway. The notochord is a structure established early in development of vertebrates and recedes during the ossification of the vertebral centra. After studying much fetal material of several taxa of ichthyosaurs across phylogeny we established that the relative size of the notochord pit can function as a proxy for determining prenatal stage (as compared to Stenopterygius). This shows that the developmental pathway is relatively conservative across ichthyosaurs, as expected, and will help in determining prenatal stage in the absence of cranial material in subsequent finds. Lastly the birth preference of ichthyosaurs was re-evaluated. A longstanding idea within the community was that ichthyosaurs preferentially (and almost exclusively) gave birth tail-first as head-first birth would increase the risk of drowning of the fetus during birth. An early diverging ichthyosaur, Chaohusaurus, was found to have head-first birth. The authors argued that it must be the ancestral and terrestrial condition, citing the drowning hypothesis. After studying three pregnant specimens of the ichthyosaur Mixosaurus, we assessed birthing orientation in all ichthyosaurs in which pregnant specimens are known. Moreover, we looked at birthing in aquatic and terrestrial extant and all extinct aquatic amniotes. We see no link between birthing in an aquatic medium and tail-first birth and thereby deem the drowning hypothesis improbable. We propose two new hypotheses for birth orientation preference. Furthermore, based on all known ichthyosaur fetuses we propose that a preference for tail-first birth originated much later in ichthyosaur evolution than previously anticipated.
Pachycormid fishes from the early jurassic (Toarcian) Posidonienschiefer formation of southern Germany
(2023) Cooper, Samuel Lewis Alan; Schoch, Rainer
Pachycormiformes were a successful clade of Mesozoic actinopterygian fishes, with a patchy fossil record spanning the Lower Jurassic to Upper Cretaceous. Current phylogeny resolves pachycormids as a monophyletic grouping of stem-teleosts (Teleosteomorpha) and therefore they hold an important evolutionary position in the debated Neopterygii to Teleostei transition. The Toarcian Posidonienschiefer Formation – a marine Konservat Lagerstätte deposited predominately in Baden-Württemberg (SW Germany) – records the oldest occurrences of Pachycormiformes in the fossil record, along with the first ~3 million years of their evolutionary history. The formation is therefore ideal for testing major evolutionary concepts for this clade; including their origins, early diversity, palaeoecology, early adaptive radiation, and survivorship across the Early Toarcian Oceanic Anoxic Event (ETOAE). Pachycormids are geographically confined the north-western Tethys during the Toarcian, with their fossils found in Liassic black shales and marls of the UK, France, Belgium, Luxembourg, Germany and northern Italy. Of the supposed 17 pachycormid species previously cited as being present in Posidonienschiefer Formation by various authors, I consider only 9 species to be valid; although just 7 of these are actually present in the German Lias: Euthynotus incognitus, Euthynotus intermedius, Sauropsis veruinalis, Pachycormus macropterus, Saurostomus esocinus, Germanostomus pectopteri, and Ohmdenia multidentata. Unfortunately, most of these taxa are poorly described and inadequately diagnosed, thus creating a caveat of problems surrounding their taxonomic identities. Many specimens are commonly misidentified, both in museum collections and published datasets, which is a major hindrance preventing reliable anatomical and evolutionary studies on Pachycormiformes. The primary objective of this thesis is to resolve the taxonomic identifies of certain Toarcian pachycormids in the Posidonienschiefer Formation, and provide a constrain on their stratigraphic and palaeobiogeographic ranges (Chapters 2, 3, Appendix 1). Only after this is resolved can the bigger questions surrounding pachycormid evolution and diversity through time be more accurately addressed. Provided in Chapter 1 is a detailed overview of the known stratigraphic and palaeobiogeographic ranges of named pachycormid taxa across their fossil record. Herein, I highlight notable gaps in their occurrences, changes in species richness through time, and discuss the abiotic and human factors biasing the pachycormid fossil record. Peaks in taxic diversity appear to correlate with eustatic sea level rise, whilst low stand periods and an associated depletion of suitable fossiliferous deposits are responsible for gaps. In Chapter 2, I review and redescribe the problematic historic species Saurostomus esocinus, providing a revised diagnosis, phylogeny, distribution ranges, and new definitive criteria to differentiate this taxon from the commonly conflated genus, Pachycormus. S. esocinus is shown to be an early diverging member of the suspension-feeding lineage of pachycormids due the detection of important shared characters (e.g., loss of infraorbital and suborbital bones; reduced skeleton ossification). I also describe a new large pachycormid from the Posidonienschiefer Formation and discuss its evolutionary significance to the evolution of suspension-feeding capabilities in Pachycormiformes. Germanostomus pectopteri is differentiated from Saurostomus esocinus by proportionately more elongate jaws, an enlarged premaxilla, loss of the opercular process on the hyomandibula, and large inverted ‘D’-shaped pectoral fins which are suitable for upwards lift. Morphologies and trends in the pachycormiform gastrointestinal tract are also discussed in an evolutionary context. Classification of Pachycormiformes is revised with the monospecific Family Pachycormidae now divided into two Subfamilies: Asthenocorminae and Hypsocorminae. Additionally, I review the ecology of Pachycormus macropterus – the most abundant and wide spread pachycormid species in the Early Jurassic. A dietary shift in prey preference associated with ontogeny is identified in P. macropterus, with juveniles obligate piscivores and adults facultatively teuthophagous. One P. macropterus specimen preserves a large ammonite shell inside of the gut, demonstrating a previously unknown trophic relationship between pachycormids and ammonoids. Evidence for cannibalism in pachycormids, based on conspecific gut contents in Pachycormus, is presented for the first time. Body size distribution in Pachycormus specimens between different sites (Curcy, France, and Holzmaden, Germany) suggest that juveniles occupied mostly coastal environments but migrated further off-shore later in ontogeny, possibly to exploit the high abundance of pelagic coleoids in these areas. Comparisons in gut contents suggest that interspecific competition between large asthenocormine pachycormids was likely low in the Posidonienschiefer Formation with Pachycormus favouring non-belemnoid teuthids (e.g. Teudopsis sp.), Saurostomus and Germanostomus consuming mainly non-belemnite belemnoids (e.g. Clarkeiteuthis conocauda) and small fishes, whilst only Ohmdenia multidentata ate belemnites. Changes in species abundance and taxic diversity of pachycormids in the Posidonienschiefer Formation is likely associated with changing water depth. Pachycormids have a low detection rate in the lower beds (tenuicostatum Zone), but become extremely abundant following the fallout of the ETOAE in the serpentinum Zone, only to drastically decline in the upper part of the section (bifrons Zone). External to Pachycormiformes, a new genus and species of coccolepidid fish (Coccolepididae) is described from the Posidonienschiefer Formation at Holzmaden (Chapter 6); the first to be named from the Toarcian, including one specimen preserved as a regurgitalite (Speiballen).
From glands to ground plans: Evolutionary morphology in Hymenoptera through space and time
(2023) Ulmer, Jonah Michael; Krogmann, Lars
Hymenoptera is one of the most species-rich and diverse groups of life, with over 153000 extant species described and another 2000 extinct. The evolutionary history of the group spans from the Triassic, around 250 million years ago, to the present day. In that time the order has spread and adapted to nearly every corner of the earth and nearly every conceivable ecological niche. That adaptation and time has led to innumerable forms and morphologies which have come and gone. Understanding the underlying patterns and impacts of these forms is perhaps the most fundamental and significant endeavor within systematics. In the first chapter, the earliest lineage of the megadiverse Chalcidoidea, Protoididae, is described from fourteen pieces of amber from the Lower Cretaceous, approximately 130 million years ago. Two genera and ten new species are described along with a key to the new family. This newly discovered stem-group chalcid provides unique insights into the early ground-plan of the superfamily which is investigated relative to other fossil and early crown-group lineages. From a thorough morphological investigation of the group, we evaluate the earliest forms of known plesiomorphies and hypothesize the transitionary forms of stem-group to crown-group chalcids. Due to its age, Protoitidae also allows us to examine the early transition of chalcids and their ground-plan relative to other early Proctotrupomorpha. Based on this study we provide palaeontological and morphological evidence for a late Cretaceous radiation in the superfamily and a modified hypothesis for the biogeographic origins of chalcid wasps. Based on the diversity of paleotaxa from the Cretaceous, an early, unsuccessful diversification event in the Cretaceous is hypothesized prior to the mega-radiation of the early Eocene. The presence of a “gap” in the paleocene record is also discussed and the utility of morphological data from the fossil record clarifies uncertainty in the parallelism versus secondary reversal in some characters in early crown-group lineages. Several ground-plan characters are confirmed from within the family, such as tarsal and antennomere counts, along with a putative plesiomorphy within Proctotrupomorpha of a strongly, proximally curving basal vein. In the second chapter, a metapleural gland is described from the parasitoid wasp Pelecinus polyturator. The unique gland is previously known only from Formicidae where it is hypothesized to be a key innovation in eusociality and an autapomorphy for the family. The gland is investigated both morphologically, behaviorally and chemically relative to the metapleural gland of ants. Hypotheses as to why the evolution of the gland was so impactful for ant diversification and less so for Pelecinidae are presented. The gland is shown to be the product of deep convergence within Hymenoptera due to a lack of transitional forms between the distantly related groups. Using this research as a basis, the “homology problem” of exocrine glands in insects is explored and formalized due to the presence of disparate evolutionary pathways occurring in a single organ system, the biosynthetic and morphological. Exaptation rather than adaptation is hypothesized to be the primary driver of glandular diversity in Hymenoptera. Within Pelecinidae, the gland ultrastructure and gross morphology is similar to that of the primitive ant lineages, suggesting a base form of the gland within Hymenoptera is present. The subsequent diversification and exaptation of the metapleural gland in Formicidae is hypothesized to be driven by eusociality, which is lacking in the asocial, parthenogenic pelecinids. A novel evolutionary model for examining exocrine glands is proposed with respect to underlying gene regulatory networks which signal the formation of exocrine glands in “hotspot” regions of the body while the biosynthetic pathways are highly homoplastic. Collectively, this work aims to elucidate the potential causes and effects of morphological “innovation” which leads to diversification in taxa. The examination of the earliest taxa of a hyper-diverse lineage provides insight into the ancestral states and morphology prior to radiation, and provides additional evidence for ground-plan characters. In lineages which have a dense radiation event such as Chalcidoidea, the transitionary forms of characters can be easily lost or obscured within a sparse fossil record, or overwhelmed by convergence and reversals across multiple lineages through time. Homoplasy can also be a boon for examining the impact of morphological innovation on diversification in a lineage relative to a convergent structure in a different group which is less successful.
Regulation of fibroblast growth factor 23 (FGF23) in metabolic derangement
(2024) Alber, Jana; Föller, Michael
Increased incidence of metabolic syndrome is attributable to Western dietary patterns. Metabolic syndrome enhances risk of developing diabetes mellitus type 2 or cardiovascular diseases, which are associated with lactic acidosis, diabetic ketoacidosis and hyperhomocysteinemia. Increased lactate, ketone body or homocysteine levels are therefore relevant indicators of impaired metabolism and pathogenesis. FGF23 is an important regulator of calcitriol and phosphate homeostasis, and is predominantly synthesized in bone cells. Synthesis of FGF23 is regulated by various mechanisms including insulin/IGF1, mTOR, AMPK, PPARα, inflammation and oxidative stress. Increased FGF23 serum levels are correlated to inflammatory, renal and cardiovascular diseases, thus FGF23 represents an important therapeutic target and disease marker. Investigations unveiling regulation of FGF23 expression and synthesis as well as underlying mechanisms are therefore of high clinical significance. Hence, the present work aimed to elucidate a relevance of impaired metabolism on FGF23 formation, therefore establishing a basis for improved diagnosis as well as therapeutic approaches reducing morbidity and mortality in lactic acidosis, diabetic ketoacidosis or hyperhomocysteinemia. To this end, regulation of FGF23 synthesis under the influence of lactate, ketone bodies and homocysteine was analyzed. Lactic acid and sodium lactate enhanced Fgf23 expression in UMR106 osteoblast-like cells, an effect translated into higher cFGF23 concentration in cell culture supernatants. Application of NFκB inhibitors wogonin and withaferin A demonstrated an NFκB-mediated up-regulation of Fgf23 expression through lactic acid. Despite the knowledge that NFκB is an inducer of FGF23 formation and lactate stimulates NFκB activity, this study is the first to reveal a direct regulation of lactate on FGF23 production. As lactic acidosis is a common comorbidity in diabetes mellitus type 2 or cancer and increased lactate serum concentrations are associated with higher mortality, the findings of this study demonstrate FGF23 to be another useful biomarker for disease monitoring and prognosis. Furthermore homocysteine is a new regulator of FGF23 synthesis as shown within the present work, thus increasing Fgf23 expression and cFGF23 abundance in UMR106 cells. This effect is mediated by enhanced oxidative stress which stimulates FGF23 production, and is abolished by application of anti-oxidative ascorbic acid. Homocysteine serum levels are associated with versatile pathologies and its link to FGF23 signaling is therefore of clinical relevance, particularly in cardiovascular and renal diseases. In another investigation as part of this work, the ketone body βHB was identified as stimulator of FGF23 synthesis in UMR106 osteoblast-like cells as well as in primary cardiomyocytes, NRVM. Within NRVM, regulation of Fgf23 expression was shown to be dependent on MCT1/2 and HCAR2. Furthermore, intracellular activation of NFκB by βHB impacting on FGF23 synthesis was demonstrated in UMR106 cells. Moreover, short-term fasting (16 h) or βHB sodium salt administration increased FGF23 serum concentrations in C57BL/6 mice. These effects are of high relevance, since fasting-induced FGF23 synthesis was associated with lower NaPi-IIa and αklotho expression as well as with higher Cyp24a1 expression. In line with high FGF23 levels and enhanced Cyp24a1 expression, calcitriol serum levels of fasted animals were significantly lower compared to mice fed ad libitum. Other serum parameters including phosphate, calcium and PTH did not differ between both study groups. Further investigations revealed an important role of the heart as well as of thymus, spleen and pancreas in fasting-induced FGF23 synthesis. However, Fgf23 expression in bone and bone marrow did not differ between fasted mice and mice fed ad libitum, and was not detectable in liver tissue. As fasting and ketone body production are thought to be beneficial for various diseases and longevity, the findings of this investigation have enormous clinical implications. Since FGF23 has been demonstrated to be an important disease marker, and fasting induces FGF23 synthesis, blood samples of patients in fasting states may require careful interpretation. In conclusion, the present work is the first to demonstrate a direct regulation of FGF23 synthesis through lactate, ketone bodies and homocysteine. Hereby, NFκB signaling and generation of oxidative stress play a pivotal role. As FGF23 formation has been shown to be regulated through short-term fasting and to impact on phosphate homeostasis within the present work, the findings are highly implicated in physiology and pathophysiology. With respect to development of cardiovascular or renal diseases through lactic acidosis, diabetic ketoacidosis and homocysteinemia as well as to the relevance of FGF23 in these pathologies, the results of the present work are of significance for improved disease monitoring and establishment of new therapeutic approaches. Future investigations examining an involvement of metabolic regulators, e.g. insulin, mTOR, AMPK, PPARα, or of FGF co-receptor αklotho may provide further promising targets for therapy, diagnosis and prognosis of metabolic diseases.
Einfluss von klimatischen Faktoren auf das Quartiernutzungsverhalten des Großen Mausohrs (Myotis myotis) in Deutschland
(2024) Matthäus, Laura; Fietz, Joanna
Um dem dramatischen Artenrückgang der letzten Jahrzehnte entgegenzuwirken und die Folgen des Klimawandels einschätzen und seine Auswirkungen bewerten zu können, ist es unerlässlich, die Auswirkungen der klimatischen Veränderungen auf die Fauna zu beobachten. Nur auf dieser Grundlage können wirksame Maßnahmen zum Schutz der Arten ergriffen werden. Auch bei den Fledermäusen kam es ab Mitte der 1950er Jahre zu einem massiven Rückgang der Populationen mehrerer europäischer Fledermausar- ten. Bei einer dieser Arten handelt es sich um das Große Mausohr (Myotis myotis), für welches Deutschland aufgrund der weltweiten Verbreitung der Art sowie der Verteilung der Weltpopulation eine besondere Verantwortung trägt. Um auf Basis der FFH- Richtlinie, in deren Anhang II und Anhang IV das Große Mausohr geführt wird, dauerhaft einen wirksamen Schutz der Art in Deutschland gewährleisten zu können, war das Ziel der vorliegenden Dissertation, den Einfluss klimatischer Faktoren auf das Quartiernut- zungsverhalten des Großen Mausohrs zu untersuchen und ein Konzept für ein kontinu- ierliches bundesweites Monitoringsystem zu entwickeln. Es wird angenommen, dass die Änderungen klimatischer Faktoren Einfluss auf den Energieverbrauch sowie die Nahrungsverfügbarkeit und damit auf das Nahrungssuch- verhalten, die Reproduktion und das Überleben bzw. die Bestandsentwicklung von Fle- dermäusen haben. Um die Hypothese validieren zu können, wurde zunächst untersucht, welche Erfassungsmethoden geeignete Daten hierfür liefern können. Dazu wurden visu- elle Ausflugszählungen, halbautomatisierte Infrarotvideoaufnahmen und vollautomati- sierte Lichtschrankenerfassungen an Großen Mausohr-Wochenstuben synchron durch- geführt. Anhand des Methodenvergleichs sollen zudem die ehrenamtlichen und professionellen Kartierer, Wissenschaftler sowie Fachbehörden in der Auswahl einer geeigneten Erhe- bungsmethode unterstützt werden. Da der Vergleich der Datenqualität ergeben hat, dass diesbezüglich keine signifikanten Unterschiede zwischen den drei angewandten Metho- den vorliegen und auch die Anwesenheit des Kartierers keinen Einfluss im Sinne einer Störung auf den Ausflug der Großen Mausohren hat, kann die Wahl der geeigneten Er- fassungsmethode fallspezifisch von den Rahmenbedingungen und der Zielsetzung der Studie abhängig gemacht werden. Im Fall des angestrebten bundesweiten Großen Mausohr-Monitorings zur Überwachung des Großen Mausohrbestands in Deutschland im Rahmen der FFH-Richtlinie empfiehlt sich die Durchführung von permanenten Lichtschrankenerfassungen, um anhand von Langzeitaufnahmen mögliche Bestandsveränderungen in den Wochenstuben unmittel- bar identifizieren und geeignete Maßnahmen ergreifen zu können. Bei Bedarf kann die Lichtschrankenerfassung, beispielsweise zur Validierung, stichprobenartig mit anderen Methoden kombiniert werden. Somit konnte anhand der Untersuchung zum Methoden- vergleich die Eignung der Methode der Lichtschrankenerfassung und die Validität der erzeugten Daten für die Untersuchung von Klimaeinflüssen auf die Phänologie bestätigt werden. In der Folge wurden auf Basis von Lichtschrankenerfassungen gewonnene Daten her- angezogen, um das Quartiernutzungsverhalten des Großen Mausohrs in Abhängigkeit von klimatischen Faktoren zu analysieren. Hierfür wurde ermittelt, ob die Umgebungs- temperatur (Ta) einen Einfluss auf die Phänologie des Großen Mausohrs hat. Die vorliegenden Untersuchungen haben gezeigt, dass Veränderungen der Ta einen maßgeblichen Einfluss auf die Phänologie der Großen Mausohren haben. Dabei kann sich eine Erhöhung der Ta je nach Zeitpunkt positiv oder negativ auf die Fitness der Fledermäuse auswirken. So scheinen warme Winter bis zu einer gewissen Temperatur eine frühere Rückkehr in die Wochenstuben auszulösen, was je nach den anhaltenden Witterungsbedingungen und damit der Insektenverfügbarkeit positiv oder negativ für die Fledermäuse sein kann. Ein warmes Frühjahr wiederum scheint zu einem früheren Start der Geburten zu führen, wodurch ausreichende Energiereserven für den Winterschlaf angelegt werden können. Auch hohe Temperaturen während der Laktation der Fleder- mäuse sowie ein früherer Start der Geburten führten zu einer früheren Auflösung der Wochenstube, sodass die Überwinterung der Jung- und Muttertiere günstigen Bedingun- gen unterliegt, da bereits frühzeitig Energiereserven gesammelt werden können. Nach diesen Ergebnissen ist es unerlässlich, bei der Entwicklung von Maßnahmen zum Schutz der Fledermausfauna den Einfluss der klimatischen Veränderungen auf die Fle- dermäuse miteinzubeziehen. Die Erkenntnisse aus dem Methodenvergleich sowie die Ergebnisse der Untersuchung zum Einfluss der Umgebungstemperatur auf die Phänologie des Großen Mausohr wer- den in einem die Dissertation abschließenden Monitoringkonzept angewendet. Dieses Konzept ist auf den Fledermausschutz sowie insbesondere den Schutz in den Quartie- ren ausgerichtet und sieht eine permanente Aktivitätserfassung mittels Lichtschranken- Technik vor. Es konnte ein Monitoringdesign entwickelt werden, welches bei eintreten- den Verhaltensänderungen in Wochenstuben des Großen Mausohrs das unmittelbare Ergreifen von Maßnahmen ermöglicht, wodurch ein schneller und wirksamer Schutz der Art gewährleistet werden kann. Darüber hinaus werden die erforderlichen Bestandsda- ten generiert, um der auf der FFH-Richtlinie basierenden Berichtspflicht gegenüber der EU vollumfänglich nachkommen zu können.
Concerning the photophysics of fluorophores towards tailored bioimaging compounds: A case study involving S100A9 inflammation markers
(2023) Steiner, Simon T.; Maisuls, Iván; Junker, Anna; Fritz, Günter; Faust, Andreas; Strassert, Cristian A.; Steiner, Simon T.; European Institute for Molecular Imaging, Westfälische Wilhelms-Universität Münster, Münster, Germany; Maisuls, Iván; Center for Nanotechnology, Westfälische Wilhelms-Universität Münster, Münster, Germany; Junker, Anna; European Institute for Molecular Imaging, Westfälische Wilhelms-Universität Münster, Münster, Germany; Fritz, Günter; Cellular Microbiology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Faust, Andreas; European Institute for Molecular Imaging, Westfälische Wilhelms-Universität Münster, Münster, Germany; Strassert, Cristian A.; Center for Nanotechnology, Westfälische Wilhelms-Universität Münster, Münster, Germany
A full understanding concerning the photophysical properties of a fluorescent label is crucial for a reliable and predictable performance in biolabelling applications. This holds true not only for the choice of a fluorophore in general, but also for the correct interpretation of data, considering the complexity of biological environments. In the frame of a case study involving inflammation imaging, we report the photophysical characterization of four fluorescent S100A9-targeting compounds in terms of UV–vis absorption and photoluminescence spectroscopy, fluorescence quantum yields (ΦF) and excited state lifetimes (τ) as well as the evaluation of the radiative and non-radiative rate constants (kr and knr, respectively). The probes were synthesized based on a 2-amino benzimidazole-based lead structure in combination with commercially available dyes, covering a broad color range from green (6-FAM) over orange (BODIPY-TMR) to red (BODIPY-TR) and near-infrared (Cy5.5) emission. The effect of conjugation with the targeting structure was addressed by comparison of the probes with their corresponding dye-azide precursors. Additionally, the 6-FAM and Cy5.5 probes were measured in the presence of murine S100A9 to determine whether protein binding influences their photophysical properties. An interesting rise in ΦF upon binding of 6-FAM-SST177 to murine S100A9 enabled the determination of its dissociation equilibrium constant, reaching up to KD = 324 nM. This result gives an outlook for potential applications of our compounds in S100A9 inflammation imaging and fluorescence assay developments. With respect to the other dyes, this study demonstrates how diverse microenvironmental factors can severely impair their performance while rendering them poor performers in biological media, showing that a preliminary photophysical screening is key to assess the suitability of a particular luminophore.
Haemosporidian parasite infections of Malagasy Philepittidae and Nectariniidae are driven by phylogeny rather than ecology
(2023) Barbon, Hannah; Berthoud, Jean-Louis; Woog, Friederike; Musa, Sandrine
The nectarivorous common sunbird asity (Neodrepanis coruscans) is phylogenetically closely related to the frugivorous velvet asity (Philepitta castanea), yet it shares similar habitat and foraging behaviour as the Malagasy sunbirds (Cinnyris spp.). As ecological factors have been shown to influence blood parasite prevalence, it should be tested whether parasite abundance, prevalence and diversity of N. coruscans are more similar to the sunbirds than to its relative. Therefore, blood samples (n = 156) and smears (n = 60) were tested for different blood parasites (Haemosporida, trypanosomes, filarioid nematodes) using molecular and microscopic methods. High prevalence of haemosporidian parasites was observed in all bird taxa, with rates ranging from 23% in N. coruscans to 84.6% in C. notatus. The Malagasy Cinnyris spp. exhibited a high occurrence of mixed haemosporidian infections (>76%) with various specialized lineages. Within the Philepittidae family, no Haemoproteus infection was detected and just a few cases of mixed infections. Nectariniidae species predominantly had specialized haemosporidian lineages, while Philepittidae had infections mainly caused by generalist lineages. These findings emphasize the diverse range of blood parasites in Nectariniidae, while additionally highlighting the high diversity of trypanosomes and filarioid nematodes in Philepittidae. Additionally, several newly discovered haemosporidian lineages, Trypanosoma isolates and filarioid nematode isolates were identified. Notably, Philepittidae exhibited a lower prevalence of avian haemosporidian parasites compared to Nectariniidae, possibly due to potential resistance mechanisms. Despite N. coruscans sharing similar habitat and behavioural ecology with both Cinnyris spp., it closely resembles its relative, P. castanea, in all aspects of haemosporidian parasitism.
High genetic diversity of Echinococcus canadensis G10 in northeastern Asia: Is it the region of origin?
(2023) Wassermann, Marion; Addy, Francis; Kokolova, Ludmila; Okhlopkov, Innokentiy; Leibrock, Sarah; Oberle, Jenny; Oksanen, Antti; Romig, Thomas
Echinococcus canadensis consists of 4 genotypes: G6, G7, G8 and G10. While the first 2 predominantly infect domestic animals, the latter are sylvatic in nature involving mainly wolves and cervids as hosts and can be found in the northern temperate to Arctic latitudes. This circumstance makes the acquisition of sample material difficult, and little information is known about their genetic structure. The majority of specimens analysed to date have been from the European region, comparatively few from northeast Asia and Alaska. In the current study, Echinococcus spp. from wolves and intermediate hosts from the Republic of Sakha in eastern Russia were examined. Echinococcus canadensis G10 was identified in 15 wolves and 4 cervid intermediate hosts. Complete mitochondrial cytochrome c oxidase subunit 1 (cox1) sequences were obtained from 42 worm and cyst specimens from Sakha and, for comparison, from an additional 13 G10 cysts from Finland. For comparative analyses of the genetic diversity of G10 of European and Asian origin, all available cox1 sequences from GenBank were included, increasing the number of sequences to 99. The diversity found in northeast Asia was by far higher than in Europe, suggesting that the geographic origin of E. canadensis (at least of G10) might be northeast Asia.
Prostaglandin E2 signaling through prostaglandin E receptor subtype 2 and Nurr1 induces fibroblast growth factor 23 production
(2024) Feger, Martina; Hammerschmidt, Katharina; Liesche, lona; Rausch, Steffen; Alber, Jana; Föller, Michael
Bone cells produce fibroblast growth factor 23 (FGF23), a hormone regulating renal phosphate and vitamin D homeostasis, and a paracrine factor produced in further tissues. Chronic kidney disease and cardiovascular disorders are associated with early elevations of plasma FGF23 levels associated with clinical outcomes. FGF23 production is dependent on many conditions including inflammation. Prostaglandin E2 (PGE2) is a major eicosanoid with a broad role in pain, inflammation, and fever. Moreover, it regulates renal blood flow, renin secretion, natriuresis as well as bone formation through prostaglandin E receptor 2 (EP2). Here, we studied the role of PGE2 and its signaling for the production of FGF23. Osteoblast-like UMR-106 cells were exposed to EP receptor agonists, antagonists or RNAi. Wild type and EP2 knockout mice were treated with stable EP2 agonist misoprostol. Fgf23 or Nurr1 gene expression was determined by quantitative real-time PCR, hormone and further blood parameters by enzyme-linked immunosorbent assay and colorimetric methods. PGE2 and EP2 agonists misoprostol and butaprost enhanced FGF23 production in UMR-106 cells, effects mediated by EP2 and transcription factor Nurr1. A single dose of misoprostol up-regulated bone Fgf23 expression and FGF23 serum levels in wild type mice with subtle effects on parameters of mineral metabolism only. Compared to wild type mice, the FGF23 effect of misoprostol was significantly lower in EP2-deficient mice. To conclude, PGE2 signaling through EP2 and Nurr1 induces FGF23 production. Given the broad physiological and pathophysiological implications of PGE2 signaling, this effect is likely of clinical relevance.
Ecosystem services and insect decline: The role of parasitoid Hymenoptera
(2024) Haas-Renninger, Maura; Krogmann, Lars
Parasitoid Hymenoptera provide essential ecosystem services, as they consume their arthropod hosts during their development, controlling host populations and thus contributing to the resilience of ecosystems. However, information on their taxonomic diversity, distribution and population trends are scarce even in well-studied regions such as Central Europe, making it difficult to understand how they are affected by insect decline. Reasons for this knowledge gap are the enormous diversity in contrast to their small size (microhymenoptera), which is why they are referred to as ‘dark taxa’. In recent years, many monitoring projects have been launched to study insect population trends in the context of insect decline and climate change, with a focus on well-studied target groups, such as wild bees, butterflies or beetles. However, parasitoid wasps, which are probably the most species rich group of all insects, are totally neglected although Malaise traps, which are widely used in monitoring studies, catch large numbers of parasitoid Hymenoptera and can therefore serve as a starting point to assess diversity and abundance of this important group. The present work aims to establish a baseline for parasitoid Hymenoptera diversity and abundance in semi-arid meadows in southwestern Germany in a conservational and applied context. It consists of three research papers, each of which contribute to fulfil this goal. The first research paper deals with the efficiency of the fractionator to separate microhymenoptera families from Malaise trap samples and discusses its potential for long-term monitoring studies. The fractionator is an affordable and user-friendly apparatus based on a plastic tub with a sieve that is placed on an orbital shaker. When the complete sample is poured in, it can be separated by shaking into two size fractions. In this study it was used to separate microhymenoptera families from a Malaise trap sample. The results show that 24 out of 34 Hymenoptera families (71 %) were separated into one of the two size fractions, which proves that the fractionator can be a helpful tool to make microhymenoptera from bulk samples accessible for further taxonomic work. In the second research paper, Malaise trap samples from an ongoing insect monitoring program were used to study the relationship of total insect biomass to abundance and diversity of microhymenoptera, as well as to assess the phenology of microhymenoptera families. Microhymenoptera abundance and diversity were positively correlated with total insect biomass, suggesting that insect biomass can be a valuable proxy for abundance trends even for small-sized insects such as microhymenoptera. Further, 90,452 specimens from 26 families belonging to 10 superfamilies of Hymenoptera were counted in total. Microhymenoptera showed two main activity periods during the year, reaching a first peak between June and July and a second between July and August. We could not find any evidence for a negative impact of mowing or grazing on the abundance of microhymenoptera. The families showed different phenological patterns, with varying numbers of activity peaks, and with some families being abundant very early (e.g. Platygastridae) or very late in the season (e.g. Figitidae, Trichogrammatidae). This is the first baseline for microhymenoptera occurrence patterns in Central Europe. The third research paper assesses the effect of mowing on microhymenoptera and how this effect can be reduced through arthropod-friendly mowing techniques, such as an adapted mowing head and a flushing bar. The results show that mowing with a conventional mulching mower has a detrimental effect on microhymenoptera with a loss of up to 64 % of individuals. The adapted mowing head had an effect only on Chalcidoidea, sparing 38 % of individuals compared to the conventional mower. The flushing bar had only a limited positive impact, because it showed a significant effect on total number of microhymenoptera with a significant reduction of 30 % on Chalcidoidea and a tendency for Ichneumonoidea with a reduction of 47 %. This shows that the conventional mowing head can have serious effects on microhymenoptera and that the effect can only be partially mitigated by insect-friendly mowing techniques. I presented the benefits and the limitations of implementing the fractionator in a monitoring workflow. As a positive example, using the fractionator enabled me to create the dataset of research paper 2, which together with research paper 3 can be a valuable reference for adapting schedules for plant protection measures and mowing dates. Insect biomass is strongly correlated with microhymenoptera abundance (research paper 2), which implies that microhymenoptera follow similar negative trends as other insects, but more meadows would need to be included to support our findings. I sorted microhymenoptera from Malaise trap samples as well as suction samples, resulting in different dominating families. Therefore a variety of collecting methods are necessary to assess the whole diversity of parasitoid Hymenoptera. All 103,312 specimens that I processed during my doctoral work are assessed in a digital database, and available for further morphological and molecular work. By linking an insect monitoring initiative with the taxonomically focused GBOLIII: Dark Taxa project, I was able to bring together the best of two worlds, and these combined efforts supported the discovery of a new wasp species. In conclusion, this work lays the foundation for the long-term assessment of parasitoid Hymenoptera in meadow ecosystems and thus contributes to a better understanding of how they are affected by insect decline. It highlights the ecological importance of parasitoid Hymenoptera and serves as a resource for their conservation. In the future, focus must be laid on studying the complex species interaction networks of parasitoid Hymenoptera and associated species. Automated systems such as the DiversityScanner using AI in combination with molecular techniques can help to gain knowledge on this highly important insect group.
The low mutational flexibility of the EPSP synthase in Bacillus subtilis is due to a higher demand for shikimate pathway intermediates
(2023) Schwedt, Inge; Schöne, Kerstin; Eckert, Maike; Pizzinato, Manon; Winkler, Laura; Knotkova, Barbora; Richts, Björn; Hau, Jann-Louis; Steuber, Julia; Mireles, Raul; Noda‐Garcia, Lianet; Fritz, Günter; Mittelstädt, Carolin; Hertel, Robert; Commichau, Fabian M.
Glyphosate (GS) inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase that is required for aromatic amino acid, folate and quinone biosynthesis in Bacillus subtilis and Escherichia coli. The inhibition of the EPSP synthase by GS depletes the cell of these metabolites, resulting in cell death. Here, we show that like the laboratory B. subtilis strains also environmental and undomesticated isolates adapt to GS by reducing herbicide uptake. Although B. subtilis possesses a GS-insensitive EPSP synthase, the enzyme is strongly inhibited by GS in the native environment. Moreover, the B. subtilis EPSP synthase mutant was only viable in rich medium containing menaquinone, indicating that the bacteria require a catalytically efficient EPSP synthase under nutrient-poor conditions. The dependency of B. subtilis on the EPSP synthase probably limits its evolvability. In contrast, E. coli rapidly acquires GS resistance by target modification. However, the evolution of a GS-resistant EPSP synthase under non-selective growth conditions indicates that GS resistance causes fitness costs. Therefore, in both model organisms, the proper function of the EPSP synthase is critical for the cellular viability. This study also revealed that the uptake systems for folate precursors, phenylalanine and tyrosine need to be identified and characterized in B. subtilis.
Recombinant production and characterization of metalloproteins from bacterial pathogens and the innate immune response
(2024) Göbel, Katharina; Fritz, Günter
The challenges and potential solutions of drug development are highlighted by discussing the identification, production and characterization of potential new drug targets in this study. The successful development of new and specific pharmaceuticals requires that the target for the respective new drug is available as a pure and homogenous molecule in its native state. Typically, the target molecule is a protein. E.g. antibacterial drugs target proteins from a bacterial pathogen or in human diseases pharmaceuticals predominantly target proteins of signaling pathways or receptors. These proteins are usually not available directly from the organism itself and have to be produced in an expression host and purified to homogeneity. Despite the advances in the field of recombinant protein expression and purification many proteins are very difficult to produce and thus represent the major bottleneck in the development of new pharmaceuticals. In particular demanding is the expression of metalloproteins, which make up to 30% of all proteins coded in the human genome and represent a major challenge in recombinant protein production. Metalloproteins are a diverse class of proteins that is crucial for various biological processes. They play an important role in the regulation, catalysis, and maintenance of biomolecular structure. Alone, 10% of all human proteins contain zinc ions and 2% contain iron, and both metal ions are often inserted by specific but so far unknown chaperones impeding the recombinant production of correctly folded and active proteins. The challenges in studying these metalloproteins arise from their complex structures and the difficulty of their expression and isolation. To overcome these problems new approaches and solutions are highlighted and exemplified by the production and characterization of potential new drug targets in this study. The focus lies particularly on metalloproteins that play a role in infectious diseases. Global health challenges include the persistent threat of infectious diseases despite advances in healthcare, hygiene and therapeutics. The COVID-19 pandemic and rising antibiotic resistance are prime examples of the ongoing risks. This research focuses on three different proteins: (1) the maturation factor NqrM from the bacterial pathogen Vibrio cholerae, (2) the human regulator of the interferon response ubiquitin-specific protease 18 (USP18) and its interaction partners, as well as (3) the viral Papain-like protease (PLpro) from the pathogenic virus SARS-CoV-2. All three proteins belong to the class of metalloproteins and bind either iron as in the case of NqrM or zinc as for USP18 and PLpro. New methods and strategies were developed to produce, isolate and investigate these metalloproteins and since all three proteins represent potential drug targets the results presented here provide the basis for future drug development. The production of proteins requires the selection of appropriate expression host systems such as bacteria, yeast, mammalian cells, etc., depending on the desired application. The study emphasizes the versatility of expression host E. coli due to its well-studied genetics, rapid growth kinetics and ease of handling. However, challenges such as the lack of post-translational modifications can lead to the production of non-functional proteins. Optimization of expression strategies is crucial, and the study describes various factors affecting protein production, including protein engineering, growth conditions, media composition and induction parameters expanding and enhancing the well-established E.coli expression system also for very challenging target proteins. The successful isolation of the proteins formed the fundamental basis for a detailed functional and structural characterization of the proteins. The research presented here takes a forward approach and encompasses the new strategies in cloning, recombinant expression and purification of proteins from bacteria, viruses and humans, emphasizing the advantages and disadvantages of homo- and heterologous recombinant expression. The results obtained highlight also the need for extensive experimental testing to establish optimal conditions, particularly for challenging proteins such as the metalloproteins studied here.
Limitations of soil-applied non-microbial and microbial biostimulants in enhancing soil P turnover and recycled P fertilizer utilization: A study with and without plants
(2024) Herrmann, Michelle Natalie; Griffin, Lydia Grace; John, Rebecca; Mosquera-Rodríguez, Sergio F.; Nkebiwe, Peteh Mehdi; Chen, Xinping; Yang, Huaiyu; Müller, Torsten
Introduction: Phosphorus recovery from waste streams is a global concern due to open nutrient cycles. However, the reliability and efficiency of recycled P fertilizers are often low. Biostimulants (BS), as a potential enhancer of P availability in soil, could help to overcome current barriers using recycled P fertilizers. For this, a deeper understanding of the influence of BSs on soil P turnover and the interaction of BSs with plants is needed. Methods: We conducted an incubation and a pot trial with maize in which we testednon-microbial (humic acids and plant extracts) and microbial BSs (microbial consortia) in combination with two recycled fertilizers for their impact on soil P turnover, plant available P, and plant growth. Results and discussion: BSs could not stimulate P turnover processes (phosphatase activity, microbial biomass P) and had a minor impact on calcium acetate-lactate extractable P (CAL-P) in the incubation trial. Even though stimulation of microbial P turnover by the microbial consortium and humic acids in combination with the sewage sludge ash could be identified in the plant trial with maize, this was not reflected in the plant performance and soil P turnover processes. Concerning the recycled P fertilizers, the CAL-P content in soil was not a reliable predictor of plant performance with both products resulting in competitive plant growth and P uptake. While this study questions the reliability of BSs, it also highlights the necessity toimprove our understanding and distinguish the mechanisms of P mobilization in soil and the stimulation of plant P acquisition to optimize future usage.
Identification of ZBTB26 as a novel risk factor for congenital hypothyroidism
(2021) Vick, Philipp; Eberle, Birgit; Choukair, Daniela; Weiss, Birgit; Roeth, Ralph; Schneider, Isabelle; Paramasivam, Nagarajan; Bettendorf, Markus; Rappold, Gudrun A.
Congenital primary hypothyroidism (CH; OMIM 218700) is characterized by an impaired thyroid development, or dyshormonogenesis, and can lead to intellectual disability and growth retardation if untreated. Most of the children with congenital hypothyroidism present thyroid dysgenesis, a developmental anomaly of the thyroid. Various genes have been associated with thyroid dysgenesis, but all known genes together can only explain a small number of cases. To identify novel genetic causes for congenital hypothyroidism, we performed trio whole-exome sequencing in an affected newborn and his unaffected parents. A predicted damaging de novo missense mutation was identified in the ZBTB26 gene (Zinc Finger A and BTB Domain containing 26). An additional cohort screening of 156 individuals with congenital thyroid dysgenesis identified two additional ZBTB26 gene variants of unknown significance. To study the underlying disease mechanism, morpholino knock-down of zbtb26 in Xenopus laevis was carried out, which demonstrated significantly smaller thyroid anlagen in knock-down animals at tadpole stage. Marker genes expressed in thyroid tissue precursors also indicated a specific reduction in the Xenopus ortholog of human Paired-Box-Protein PAX8, a transcription factor required for thyroid development, which could be rescued by adding zbtb26. Pathway and network analysis indicated network links of ZBTB26 to PAX8 and other genes involved in thyroid genesis and function. GWAS associations of ZBTB26 were found with height. Together, our study added a novel genetic risk factor to the list of genes underlying congenital primary hypothyroidism and provides additional support that de novo mutations, together with inherited variants, might contribute to the genetic susceptibility to CH.
Up-regulation of fibroblast growth factor 23 gene expression in UMR106 osteoblast-like cells with reduced viability
(2021) Münz, Sina; Feger, Martina; Edemir, Bayram; Föller, Michael
Fibroblast growth factor 23 (FGF23) controls vitamin D and phosphate homeostasis in the kidney and has additional paracrine effects elsewhere. As a biomarker, its plasma concentration is associated with progression of inflammatory, renal, and cardiovascular diseases. Major stimuli of FGF23 synthesis include active vitamin D and inflammation. Antineoplastic chemotherapy treats cancer by inducing cellular damage ultimately favoring cell death (apoptosis and necrosis) and causing inflammation. Our study explored whether chemotherapeutics and other apoptosis inducers impact on Fgf23 expression. Experiments were performed in osteoblast-like UMR106 cells, Fgf23 gene expression and protein synthesis were determined by qRT-PCR and ELISA, respectively. Viability was assessed by MTT assay and NFκB activity by Western Blotting. Antineoplastic drugs cisplatin and doxorubicin as well as apoptosis inducers procaspase-activating compound 1 (PAC-1), a caspase 3 activator, and serum depletion up-regulated Fgf23 transcripts while reducing cell proliferation and viability. The effect of cisplatin on Fgf23 transcription was paralleled by Il-6 up-regulation and NFκB activation and attenuated by Il-6 and NFκB signaling inhibitors. To conclude, cell viability-decreasing chemotherapeutics as well as apoptosis stimulants PAC-1 and serum depletion up-regulate Fgf23 gene expression. At least in part, Il-6 and NFκB may contribute to this effect.
Tachysterol2 increases the synthesis of fibroblast growth factor 23 in bone cells
(2022) Ewendt, Franz; Kotwan, Julia; Ploch, Stefan; Feger, Martina; Hirche, Frank; Föller, Michael; Stangl, Gabriele I.
Tachysterol2 (T2) is a photoisomer of the previtamin D2 found in UV-B-irradiated foods such as mushrooms or baker’s yeast. Due to its structural similarity to vitamin D, we hypothesized that T2 can affect vitamin D metabolism and in turn, fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone that is transcriptionally regulated by the vitamin D receptor (VDR). Initially, a mouse study was conducted to investigate the bioavailability of T2 and its impact on vitamin D metabolism and Fgf23 expression. UMR106 and IDG-SW3 bone cell lines were used to elucidate the effect of T2 on FGF23 synthesis and the corresponding mechanisms. LC-MS/MS analysis found high concentrations of T2 in tissues and plasma of mice fed 4 vs. 0 mg/kg T2 for 2 weeks, accompanied by a significant decrease in plasma 1,25(OH)2D and increased renal Cyp24a1 mRNA abundance. The Fgf23 mRNA abundance in bones of mice fed T2 was moderately higher than that in control mice. The expression of Fgf23 strongly increased in UMR106 cells treated with T2. After Vdr silencing, the T2 effect on Fgf23 diminished. This effect is presumably mediated by single-hydroxylated T2-derivatives, since siRNA-mediated silencing of Cyp27a1, but not Cyp27b1, resulted in a marked reduction in T2-induced Fgf23 gene expression. To conclude, T2 is a potent regulator of Fgf23 synthesis in bone and activates Vdr. This effect depends, at least in part, on the action of Cyp27a1. The potential of oral T2 to modulate vitamin D metabolism and FGF23 synthesis raises questions about the safety of UV-B-treated foods.
Low-input high-molecular-weight DNA extraction for long-read sequencing from plants of diverse families
(2022) Russo, Alessia; Mayjonade, Baptiste; Frei, Daniel; Potente, Giacomo; Kellenberger, Roman T.; Frachon, Léa; Copetti, Dario; Studer, Bruno; Frey, Jürg E.; Grossniklaus, Ueli; Schlüter, Philipp M.
Long-read DNA sequencing technologies require high molecular weight (HMW) DNA of adequate purity and integrity, which can be difficult to isolate from plant material. Plant leaves usually contain high levels of carbohydrates and secondary metabolites that can impact DNA purity, affecting downstream applications. Several protocols and kits are available for HMW DNA extraction, but they usually require a high amount of input material and often lead to substantial DNA fragmentation, making sequencing suboptimal in terms of read length and data yield. We here describe a protocol for plant HMW DNA extraction from low input material (0.1 g) which is easy to follow and quick (2.5 h). This method successfully enabled us to extract HMW from four species from different families (Orchidaceae, Poaceae, Brassicaceae, Asteraceae). In the case of recalcitrant species, we show that an additional purification step is sufficient to deliver a clean DNA sample. We demonstrate the suitability of our protocol for long-read sequencing on the Oxford Nanopore Technologies PromethION® platform, with and without the use of a short fragment depletion kit.

Browse

Recent Submissions