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White stork (Ciconia ciconia) nestlings can provide quantitative information on the quality of the surrounding environment by indicating the presence of pollutants, as they depend on locally foraged food. This study represents the first comparison of biomarkers in two fractions of white stork nestling blood: plasma and S9 (the post-mitochondrial fraction). The aim of this study was to evaluate acetylcholinesterase (AChE), carboxylesterase (CES), glutathione S-transferase (GST), and glutathione reductase (GR), as well as to establish a novel fluorescence-based method for glutathione (GSH) and reactive oxygen species (ROS) detection in plasma and S9. Considering the enzymatic biomarkers, lower variability in plasma was detected only for AChE, as CES, GST, and GR had lower variability in S9. Enzyme activity was higher in plasma for AChE, CES, and GST, while GR had higher activity in S9. Regarding the fluorescence-based method, lower variability was detected in plasma for GSH and ROS, although higher GSH detection was reported in S9, and higher ROS was detected in plasma. The present study indicated valuable differences by successfully establishing protocols for biomarker measurement in plasma and S9 based on variability, enzyme activity, and fluorescence. For a better understanding of the environmental effects on nestlings’ physiological condition, biomarkers can be measured in plasma and S9.
In welchen Situationen steht ein Tier unter Stress und wie beeinflusst Stress dessen Wohlbefinden? Dies sind die Kernfragen, mit denen Zoos konfrontiert sind, wenn es darum geht, den Bedürfnissen ihrer Tiere gerecht zu werden. Die Beantwortung dieser Fragen ist jedoch angesichts der großen individuellen Variabilität des Inputs, der Stress hervorrufen kann,und des Outputs, der das Wohlbefinden bestimmt, eine Herausforderung. Um diese Herausforderung zu meistern, brauchen Zoos Kenntnisse darüber, welche Haltungsbedingungen und Managementsituationen Verhaltens-, physiologische oder emotionale Veränderungen hervorrufen, sowohl positive als auch negative. Dies trifft insbesondere auf Arten zu, die aufgrund ihrer Biologie und des großen öffentlichen Interesses große Anforderungen an das Management in Menschenobhut stellen, wie den Afrikanischen Elefanten. Die vorliegende Arbeit hatte daher das Ziel, unter Berücksichtigung der individuellen Variation die Auswirkungen bestimmter Managementsituationen auf physiologischen Stress und das Wohlbefinden der Tiere zu evaluieren.
Für diese Arbeit wurden zehn Afrikanische Elefanten aus drei Zoos im Rahmen eines Experiments in 2016 und 2017 mehrmals untersucht. Dieses Experiment umfasste zum einen die Messung von physiologischem Stress auf der Basis der Konzentration des „Stresshormons“ Cortisol im Speichel der Elefanten. Zu diesem Zweck wurden an bestimmten Tagen und zu folgenden Zeitpunkten Speichelproben entnommen: morgens, nachmittags vor und mehrmals nach einer von zwei Managementsituationen (positives Verstärkungstraining [PRT] und neuartiges Enrichmentobjekt [NOV]). Zum anderen diente die Exposition gegenüber dem neuartigen Enrichmentobjekt als sogenannter Novel Object Test. Dieser Standardtest der Persönlichkeitsforschung bei Tieren deckte bei anderen Arten konsistente Verhaltensunterschiede zwischen Individuen auf. Um zu untersuchen, ob dies auch auf Afrikanische Elefanten zutrifft, wurden die individuellen Verhaltensreaktionen auf das neuartige Objekt aufgezeichnet. Darüber hinaus wurden unabhängig von dem Experiment vor und nach einem Transport jeweils morgens und nachmittags Speichelproben von dem transferierten Tier und von zwei Tieren im Bestimmungszoo gesammelt, um den Effekt dieses potenziellen Stressors auf die individuellen Cortisolspiegel zu untersuchen.
Publikation A zeigt, dass die Elefanten unter den Bedingungen des Routinemanagements (das heißt dem routinemäßigen Tagesablauf der Tierpflege) am Morgen signifikant höhere Cortisolwerte im Speichel aufwiesen als am Nachmittag. Diese diurnale Variation der Cortisolsekretion ist typisch für tagaktive Arten und wurde daher auch für die untersuchten Elefanten erwartet. Unter Stressbedingungen wurde weder ein signifikanter Unterschied zwischen den Cortisolspiegeln vor und nach dem Transport noch zwischen den Cortisolwerten am Morgen und am Nachmittag festgestellt. Der prozentuale Unterschied zwischen dem morgendlichen und nachmittäglichen Cortisolspiegel war jedoch beim transferierten Tier nach dem Transport wesentlich geringer als vor dem Transport, was möglicherweise auf eine Stressreaktion auf den Transport und die Eingewöhnung im neuen Zoo hindeutet. Darüber hinaus zeigten sich deutliche Cortisolanstiege unmittelbar nach der ersten Zusammenführung des transferierten Tiers mit dem Bullen im neuen Zoo. Dieses Ergebnis demonstriert zum einen, dass Cortisol physiologischen Stress widerspiegelt. Zum anderen zeigt es die Notwendigkeit, zeitnah nach einem Stressor Speichelproben zu entnehmen, was nach dem Transport nicht möglich war.
Die Studie in Manuskript B zeigt unterschiedliche durchschnittliche Zeitverläufe der Cortisolantworten im Speichel auf die Managementsituationen PRT und NOV. PRT könnte aufgrund des beobachteten cortisolsenkenden und damit potenziell stresspuffernden Effekts förderlich für das Wohlbefinden sein. NOV induzierte im Mittel eine moderate, kurzfristige Cortisolantwort. Dies deutet darauf hin, dass die Tiere geringem physiologischem Stress ausgesetzt waren, mit dem sie jedoch erfolgreich umgehen konnten. Außerdem bestand eine bemerkenswerte individuelle Variation in den Cortisolverläufen in derselben Situation. Die Unterschiede im Cortisolspiegel zwischen den Tieren hingen mit dem Alter (bei NOV) und dem Zoo (bei PRT) zusammen. Der Effekt des Geschlechts und des Haltungssystems auf den Cortisolspiegel war hingegen variabel. Die Ergebnisse der Studie zeigen, dass die individuelle Variation der Cortisolsekretion unbedingt berücksichtigt werden muss, um physiologischen Stress zuverlässig zu erkennen.
Die Studie in Manuskript C ergab, dass sich die untersuchten Tiere im Novel Object Test konsistent in ihrem Verhalten gegenüber einem neuartigen Objekt unterschieden. Dieses Ergebnis zeigt, dass der Novel Object Test auch bei Elefanten genutzt werden kann, um die Persönlichkeit der Tiere zu untersuchen...
In the framework of the PNRA (Italian National Antarctic Research Program) project CARBONANT focusing on biogenic carbonates and held in January–February 2002, several Ross Sea banks were sampled to obtain samples of biogenic carbonates. In the Mawson Bank, species belonging to the isopod genus Chaetarcturus Brandt, 1990 were recorded, including a specimen that did not match any described species. In this paper we describe Chaetarcturus cervicornis sp. n., which is characterized by supraocular spines and two pairs of tubercle-like protrusions on the cephalothorax. The new species is very similar to C. bovinus (Brandt & Wägele, 1988) and C. adareanus (Hodgson, 1902), but has a clearly different spine pattern. The study of the species of the genus Chaetarcturus in the Ross Sea contributes to increase our knowledge on the diversity of the Antarcturidae in the Southern Ocean. Ross Sea banks seem to hold an interesting and not-well-known fauna, deserving attention in future research.
Nonmycorrhizal root-colonizing fungi are key determinants of plant growth, driving processes ranging from pathogenesis to stress alleviation. Evidence suggests that they might also facilitate host access to soil nutrients in a mycorrhiza-like manner, but the extent of their direct contribution to plant nutrition is unknown. To study how widespread such capacity is across root-colonizing fungi, we surveyed soils in nutrient-limiting habitats using plant baits to look for fungal community changes in response to nutrient conditions. We established a fungal culture collection and used Arabidopsis thaliana inoculation bioassays to assess the ability of fungi to facilitate host’s growth in the presence of organic nutrients unavailable to plants. Plant baits captured a representation of fungal communities extant in natural habitats and showed that nutrient limitation has little influence on community assembly. Arabidopsis thaliana inoculated with 31 phylogenetically diverse fungi exhibited a consistent fungus-driven growth promotion when supplied with organic nutrients compared to untreated plants. However, direct phosphorus measurement and RNA-seq data did not support enhanced nutrient uptake but rather that growth effects may result from changes in the plant’s immune response to colonization. The widespread and consistent host responses to fungal colonization suggest that distinct, locally adapted nonmycorrhizal fungi affect plant performance across habitats.
IMPORTANCE: Recent studies have shown that root-associated fungi that do not engage in classical mycorrhizal associations can facilitate the hosts’ access to nutrients in a mycorrhiza-like manner. However, the generality of this capacity remains to be tested. Root-associated fungi are frequently deemed major determinants of plant diversity and performance, but in the vast majority of cases their ecological roles in nature remain unknown. Assessing how these plant symbionts affect plant productivity, diversity, and fitness is important to understanding how plant communities function. Recent years have seen important advances in the understanding of the main drivers of the diversity and structure of plant microbiomes, but a major challenge is still linking community properties with function. This study contributes to the understanding of the cryptic function of root-associated fungi by testing their ability to participate in a specific process: nutrient acquisition by plants.
Cardiolipin, the mitochondria marker lipid, is crucially involved in stabilizing the inner mitochondrial membrane and is vital for the activity of mitochondrial proteins and protein complexes. Directly targeting cardiolipin by a chemical-biology approach and thereby altering the cellular concentration of “available” cardiolipin eventually allows to systematically study the dependence of cellular processes on cardiolipin availability. In the present study, physics-based coarse-grained free energy calculations allowed us to identify the physical and chemical properties indicative of cardiolipin selectivity and to apply these to screen a compound database for putative cardiolipin-binders. The membrane binding properties of the 22 most promising molecules identified in the in silico approach were screened in vitro, using model membrane systems finally resulting in the identification of a single molecule, CLiB (CardioLipin-Binder). CLiB clearly affects respiration of cardiolipin-containing intact bacterial cells as well as of isolated mitochondria. Thus, the structure and function of mitochondrial membranes and membrane proteins might be (indirectly) targeted and controlled by CLiB for basic research and, potentially, also for therapeutic purposes.
Alternative splicing (AS) is a major mechanism for gene expression in eukaryotes, increasing proteome diversity but also regulating transcriptome abundance. High temperatures have a strong impact on the splicing profile of many genes and therefore AS is considered as an integral part of heat stress response. While many studies have established a detailed description of the diversity of the RNAome under heat stress in different plant species and stress regimes, little is known on the underlying mechanisms that control this temperature-sensitive process. AS is mainly regulated by the activity of splicing regulators. Changes in the abundance of these proteins through transcription and AS, post-translational modifications and interactions with exonic and intronic cis-elements and core elements of the spliceosomes modulate the outcome of pre-mRNA splicing. As a major part of pre-mRNAs are spliced co-transcriptionally, the chromatin environment along with the RNA polymerase II elongation play a major role in the regulation of pre-mRNA splicing under heat stress conditions. Despite its importance, our understanding on the regulation of heat stress sensitive AS in plants is scarce. In this review, we summarize the current status of knowledge on the regulation of AS in plants under heat stress conditions. We discuss possible implications of different pathways based on results from non-plant systems to provide a perspective for researchers who aim to elucidate the molecular basis of AS under high temperatures.
First-principle metabolic modelling holds potential for designing microbial chassis that are resilient against phenotype reversal due to adaptive mutations. Yet, the theory of model-based chassis design has rarely been put to rigorous experimental test. Here, we report the development of Saccharomyces cerevisiae chassis strains for dicarboxylic acid production using genome-scale metabolic modelling. The chassis strains, albeit geared for higher flux towards succinate, fumarate and malate, do not appreciably secrete these metabolites. As predicted by the model, introducing product-specific TCA cycle disruptions resulted in the secretion of the corresponding acid. Adaptive laboratory evolution further improved production of succinate and fumarate, demonstrating the evolutionary robustness of the engineered cells. In the case of malate, multi-omics analysis revealed a flux bypass at peroxisomal malate dehydrogenase that was missing in the yeast metabolic model. In all three cases, flux balance analysis integrating transcriptomics, proteomics and metabolomics data confirmed the flux re-routing predicted by the model. Taken together, our modelling and experimental results have implications for the computer-aided design of microbial cell factories.
Patients harboring mutations in the gene DEPDC5 often display variations of neurological diseases including epilepsy, autism spectrum disorders (ASD) and other neuro-architectural alterations. DEPDC5 protein has been identified as an amino acid sensor responsible for negatively regulating the mechanistic target of rapamycin (mTOR), a central regulator in cell growth and cell homeostasis. Often, mutations of the DEPDC5 protein result in mTOR hyperactivity leading to abnormal neuronal phenotypes and the generation of excitatory/inhibitory imbalances in animal models. Complete knockout (KO) of DEPDC5 results in death shortly after birth, while inhibition of mTOR activity recovers postnatal death (Marsan et al. 2016). However, heterozygous DEPDC5-KOs in animals have been variable in their disease phenotypes during adulthood indicating developmental differences between subspecies and early development mechanisms which could be impactful on the outcome of the diseases.
To understand the mechanisms underlying DEPDC5 mutations during early development, a novel primary human neural progenitor cell line extracted from fetal tissue was characterized during proliferation and differentiation. CRISPR-Cas9 induced mutations of the DEPDC5 gene resulted in hyperphosphorylation of mTOR signaling processes and rapid expansion of the neuronal population during differentiation. Analysis of transcriptome data identified deregulation amongst p53 signaling, ribosome biogenesis, nucleotide and lipid synthesis as well as protein degradation pathways due to loss of DEPDC5. Disease gene datasets identified a correlation between Tuberous Sclerosis mutations as being more closely associated with DEPDC5 mutations while also finding overlap with some ASD and epilepsy genes. By using the mTOR inhibitor rapamycin, a substantial amount of the deregulated gene network was recovered while also reversing rapid neuronal differentiation caused by loss of DEPDC5. Though we saw increased dendritic arborization and subsequent decreases in dendrite lengths and soma sizes, rapamycin failed to recover these effects suggesting mTOR independent processes produced by DEPDC5-KO. This study provides new insights on the relationship between mutations in DEPDC5 and the functional, genomic and deregulatory networks it intertwines in humans and highlights that the DEPDC5 associated pathomechanisms are not fully related to mTOR hyperactivation, but include independent processes. This also sheds light on the question why rapamycin treatment only partially restores DEPDC5 related phenotypes and gives insight on treatments for DEPDC5 patients.
Oaks may contribute to the stabilization of European forests under climate change. We utilized two common gardens established in contrasting growth regimes, in Greece (Olympiada) and Germany (Schwanheim), to compare the diurnal photosynthetic performance of a Greek and an Italian provenance of two Mediterranean oaks (Quercus pubescens and Q. frainetto) during the 2019 growing season. Although the higher radiation in the southern common garden led to a strong midday depression of chlorophyll a fluorescence parameters (maximum quantum efficiency of PSII, performance index on absorption basis), comparable light-saturated net photosynthetic rates were achieved in both study areas. Moreover, both species and provenances exhibited analogous responses. Q. pubescens had enhanced chlorophyll a fluorescence traits but similar photosynthetic rates compared to Q. frainetto, whereas the provenances did not differ. These findings indicate the high photosynthetic efficiency of both oaks under the current climate in Central Europe and their suitability for assisted migration schemes.
The Brachybasidiaceae are a family of 22 known species of plant-parasitic microfungi belonging to Exobasidiales, Basidiomycota. Within this family, species of the largest genus Kordyana develop balls of basidia on top of stomatal openings. Basidial cells originate from fungal stroma filling substomatal chambers. Species of Kordyana typically infect species of Commelinaceae. During fieldwork in the neotropics, fungi morphologically similar to Kordyana spp. were found on Goeppertia spp. (syn. Calathea spp., Marantaceae), namely on G. panamensis in Panama and on G. propinqua in Bolivia. These specimens are proposed as representatives of a genus new to science, Marantokordyana, based on the distinct host family and molecular sequence data of ITS and LSU rDNA regions. The specimens on the two host species represent two species new to science, M. oberwinkleriana on G. panamensis and M. boliviana on G. propinqua. They differ by the size and shape of their basidia, molecular sequence data of ITS and LSU rDNA regions, and host plant species. In the past, the understanding of Brachybasidiaceae at order and family level was significantly improved by investigation realized by Franz Oberwinkler and his collaborators at the University of Tübingen, Germany. On species level, however, our knowledge is still very poor due to incomplete species descriptions of several existing names in literature, scarceness of specimens, as well as sequence data lacking for many taxa and for further barcode regions. Especially species of Kordyana and species of Dicellomyces are in need of revision.