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Seventeen bacterial strains able to suppress plant pathogens have been isolated from healthy Vietnamese crop plants and taxonomically assigned as members of the Bacillus cereus group. In order to prove their potential as biocontrol agents, we perform a comprehensive analysis that included the whole-genome sequencing of selected strains and the mining for genes and gene clusters involved in the synthesis of endo- and exotoxins and secondary metabolites, such as antimicrobial peptides (AMPs). Kurstakin, thumolycin, and other AMPs were detected and characterized by different mass spectrometric methods, such as MALDI-TOF-MS and LIFT-MALDI-TOF/TOF fragment analysis. Based on their whole-genome sequences, the plant-associated isolates were assigned to the following species and subspecies: B. cereus subsp. cereus (6), B. cereus subsp. bombysepticus (5), Bacillus tropicus (2), and Bacillus pacificus. These three isolates represent novel genomospecies. Genes encoding entomopathogenic crystal and vegetative proteins were detected in B. cereus subsp. bombysepticus TK1. The in vitro assays revealed that many plant-associated isolates enhanced plant growth and suppressed plant pathogens. Our findings indicate that the plant-associated representatives of the B. cereus group are a rich source of putative antimicrobial compounds with potential in sustainable agriculture. However, the presence of virulence genes might restrict their application as biologicals in agriculture.
Peatlands contribute to a wide range of ecosystem services. They play an important role as carbon sinks in their natural state, but when they are drained, they cause carbon emissions. Rewetting drained peatlands is required to reduce carbon emissions and create new carbon sinks. However, drained peatlands are commonly used as grassland or croplands; therefore, alternative agriculture schemes are required following rewetting. Paludiculture, i.e., agriculture on wet and rewetted peatlands, is an option in these areas after rewetting to produce biomass sustainably. Monitoring of peatland management is challenging, yet needed to ensure a successful rewetting and plantation of, e.g., Phragmites australis and Typha spp., two plants which are commonly used in paludiculture. Remote sensing is an excellent tool for monitoring the vegetation composition of vast rewetted peatland regions. However, because many peatland species have similar spectral characteristics, such monitoring is ideally based on high-spatial, high-temporal hyperspectral images. Data that complies with all these requirements does not exist on a regular basis. Therefore, we assessed the potential for mapping peatland vegetation communities in the Peene and Trebel river basins of the federal state of Mecklenburg-Western Pomerania, Germany, using multi-date hyperspectral (PRISMA) data. We used regression-based unmixing to map fractions of different peatland vegetation classes. Results were analyzed with regard to the contribution of multi-date observations and, in comparison, to multispectral datasets (Landsat-8/Sentinel-2). Our results showed that different classes are best mapped at different observation dates. The multi-date hyperspectral datasets produced less Mean Absolute Error (MAE = 16.4%) than the single-date hyperspectral images (ΔMAE + 1%), with high accuracies for all classes of interest. Compared to the results obtained with multispectral data from similar acquisition dates and annual spectral-temporal metrics (STM), the results from hyperspectral data were always clearly superior (ΔMAE + 4%). Besides the superior performance during comparisons, our results also indicate that information that can be derived from the hyperspectral data with the regression-based unmixing goes clearly beyond that of discrete classification. With more hyperspectral sensors coming up and an expected higher availability of multi-data hyperspectral imagery, these data can be expected to play a bigger role in the future monitoring of peatlands.
The male genitalia of pholcid spiders, which is one of the most species-rich spider families, are characterized by a procursus, which is a morphologically diverse projection of the copulatory organ. It has been shown that the procursus interacts with the female genitalia during copulation. Here, we investigate the function of the procursus in Gertschiola neuquena, a species belonging to the early branched and understudied subfamily Ninetinae, using behavioural and morphological data. Although many aspects of the copulatory behaviour of G. neuquena follow the general pattern described for the family, males use only one pedipalp during each copulation. Based on our micro-CT analysis of cryofixed mating pairs using virgin females, we can show that the long and filiform procursus is inserted deeply into the unpaired convoluted female spermatheca, and the intromittent sclerite, the embolus, is rather short and stout only reaching the most distal part of the female sperm storage organ. Histological data revealed that sperm are present in the most proximal part of the spermatheca, suggesting that the procursus is used to allocate sperm deeply into the female sperm storage organ. This represents the first case of a replacement of the sperm allocation function of the intromittent sclerite in spiders.
Background
The alignment of large numbers of protein sequences is a challenging task and its importance grows rapidly along with the size of biological datasets. State-of-the-art algorithms have a tendency to produce less accurate alignments with an increasing number of sequences. This is a fundamental problem since many downstream tasks rely on accurate alignments.
Results
We present learnMSA, a novel statistical learning approach of profile hidden Markov models (pHMMs) based on batch gradient descent. Fundamentally different from popular aligners, we fit a custom recurrent neural network architecture for (p)HMMs to potentially millions of sequences with respect to a maximum a posteriori objective and decode an alignment. We rely on automatic differentiation of the log-likelihood, and thus, our approach is different from existing HMM training algorithms like Baum–Welch. Our method does not involve progressive, regressive, or divide-and-conquer heuristics. We use uniform batch sampling to adapt to large datasets in linear time without the requirement of a tree. When tested on ultra-large protein families with up to 3.5 million sequences, learnMSA is both more accurate and faster than state-of-the-art tools. On the established benchmarks HomFam and BaliFam with smaller sequence sets, it matches state-of-the-art performance. All experiments were done on a standard workstation with a GPU.
Conclusions
Our results show that learnMSA does not share the counterintuitive drawback of many popular heuristic aligners, which can substantially lose accuracy when many additional homologs are input. LearnMSA is a future-proof framework for large alignments with many opportunities for further improvements.
The multi-cell Penning–Malmberg trap concept has been proposed as a way to accumulate and confine unprecedented numbers of antiparticles, an attractive but challenging goal. We report on the commissioning and first results (using electron plasmas) of the World's second prototype of such a trap, which builds and improves on the findings of its predecessor. Reliable alignment of both ‘master’ and ‘storage’ cells with the axial magnetic field has enabled confinement of plasmas, without use of the ‘rotating wall’ (RW) compression technique, for over an hour in the master cell and tens of seconds in the storage cells. In the master cell, attachment to background neutrals is found to be the main source of charge loss, with an overall charge-confinement time of 8.6 h. Transfer to on-axis and off-axis storage cells has been demonstrated, with an off-axis transfer rate of 50% of the initial particles, and confinement times in the storage cells in the tens of seconds (again, without RW compression). This, in turn, has enabled the first simultaneous plasma confinement in two off-axis cells, a milestone for the multi-cell trap concept.
The controlled formation and adjustment of size and density of magnetic skyrmions in Ta/CoFeB/MgO trilayers with low Dzyaloshinskii–Moriya interaction is demonstrated. Close to the out-of-plane to in-plane magnetic spin reorientation transition, we find that small energy contributions enable skyrmion formation in a narrow window of 20 pm in CoFeB thickness. Zero-field stable skyrmions are established with proper magnetic field initialization within a 10 pm CoFeB thickness range. Using magneto-optical imaging with quantitative image processing, variations in skyrmion distribution and diameter are analyzed quantitatively, the latter for sizes well below the optical resolution limit. We demonstrate the controlled merging of individual skyrmions. The overall demonstrated degree of comprehension of skyrmion control aids to the development of envisioned skyrmion based magnetic memory devices.
Recent experimental campaigns in the Wendelstein 7-X stellarator, a
plasma-confining device designed to investigate the Magnetic Confinement Fusion
(MCF) approach to generating electrical power, have shown that the injection of
fuelling pellets had an unexpected and considerable impact on the performance of
the plasma. Rather than simply refuelling the device and `diluting' the plasma
energy, pellet injection is followed by a significant increase in the ratio of
the ion temperature to the electron temperature. It has been suggested that this
is not merely due to the improved confinement following the reduction of
turbulent transport after the pellet material has homogenised with the bulk
plasma, but also due to a direct transfer of energy from electrons to ions. The
proposed mechanism for this energy transfer is the ambipolar expansion of the
pellet plasmoid, the localised plasma structure produced by the
ionisation of ablated pellet material, along magnetic field lines.
Early work on pellet plasmoid expansion predicted that half the heating power
deposited in plasmoid electrons by collisions with hot ambient electrons is
transferred to plasmoid ions in the form of flow velocity as the plasmoid
expands. The complicated nature of the system of the pellet plasmoid embedded in
the ambient plasma, particularly the behaviour of electrons, which experience
many collisional and collisionless phenomena on multiple disparate timescales,
means that early models of the expansion were not wholly self-consistent, but
rather made use of strong approximations that apply in some regions of the
plasmoid but not in others. For example, only electrons and ions associated with
the plasmoid were rigorously treated, meaning that the framework was one of
`expansion into vacuum'. Combined with the assumption of Maxwellian electrons,
this led to an electric potential that was unbounded at infinity. Naturally, the
validity of the conclusions of such a model are called into question because the
approximations lose their validity far from the plasmoid and as time advances,
yet predictions about the final state of the plasma are desired. A deeper
investigation is required: careful consideration of the phenomena in question
and the timescales (and lengthscales) on which they act must be made in order to
rigorously construct a model that is valid throughout the entire expansion.
The first two papers presented in this thesis iterate on the model established
in the paper that first predicted the electron-to-ion energy transfer; their aim
was to find out how the character of the expansion changes with a more
sophisticated and accurate description of various phenomena, while remaining
within the existing framework of expansion into vacuum. Ultimately, we find that
the qualitative character is unchanged, and that approximately half the heating
power deposited in plasmoid electrons is transferred to ions.
Two other papers in this thesis address the limitations of the original model.
This is achieved by properly considering the electron kinetic problem in a
plasmoid. One paper considers the electron kinetic problem when electrons are
highly isotropised. In this case the kinetic equation can be integrated to
remove all but two independent variables, which is the maximum possible
reduction considering it is a time-dependent problem. The full nonlinear
integro-differential Landau self-collision operator is integrated exactly and
few approximations are made, leading to a rather general kinetic equation.
However, for fuelling pellets some anisotropy in the electron distribution is
expected. Another paper considers the electron kinetic problem (and the entire
plasmoid expansion) allowing for electron anisotropy. Careful consideration of
the ordering of timescales of electron phenomena in a pellet plasmoid leads to a
steady-state kinetic problem that we call collisional quasi-equilibrium (QE). QE
appears in many ways similar to the collisional steady-state characterising a
true thermal equilibrium. It was found that the time-dependent kinetic problem
of the earlier paper, with isotropic electrons, produces the QE distribution
function, corroborating the existence of the QE state. We then take moments of
the electron kinetic equation that is valid on the expansion timescale, assuming
that the electron distribution is that given as the solution to the QE kinetic
problem. This is completely analogous to what is done to obtain the Braginskii
equations or any Chapman-Enskog theory. The result is a set of equations for the
long-term evolution of the macroscopic quantities that describe the distribution
function existing in a quasi-steady-state at each point in time. It is from this
point that one may feasibly describe the plasmoid expansion with an accurate
picture of the electron kinetics and finally obtain the electron-to-ion energy
transfer so desired in a rigorous model of the expansion.
From a broader point of view, the two frameworks provided by these rigorous
investigations of the electron kinetic problem serve as a basis for the future
study of plasmoids. Such a `first-principles' approach to plasmoid dynamics is
novel and interesting in its own right, but it will be demonstrated that such an
approach is essential for pellet plasmoids owing to the fact that they are
poorly described by the `standard tools' of plasma physics.
Using the QE framework it was found that, once more, about half the heating
power experienced by plasmoid electrons is transferred to plasmoid ions. The
incredible robustness of the prediction of such an energy transfer is, in the
author's opinion, the result of the self-similar nature of the expansion found
as a solution to the original model. As a rule, the profiles of self-similar
solutions tend to be attractors for the `real', more complicated, system, and
the qualitative predictions involving no parameters, of which the
electron-to-ion energy transfer is one, tend to be very sturdy.
Aside from fuelling pellets, composed of hydrogen or deuterium, one paper in
this thesis investigates the physics of high-Z pellets that are designed to
terminate the plasma safely in the event of a `disruption', where much of the
magnetic field energy is channelled into a runaway electron beam with
potentially disastrous consequences if the beam encounters a plasma-facing
component. The paper draws on the work carried out in the paper concerning the
kinetic problem of isotropised electrons in a plasmoid.
This thesis is `cumulative'; the vast majority of the work carried out is
described within a set of Papers, labelled A-E, placed at the back of the text.
There is a preceding `wrapper text' (given in numbered Sections) tasked with
introducing the reader to the topic, guiding the reader through the papers, and
expounding some of their main results. Some amount of material not present in
the papers is also provided in the wrapper text. Naturally, the wrapper text
mainly focusses on the results of the papers which are under my first
authorship. In the course of publishing papers over an extended period of time
the nomenclature is bound to vary. Although it is mostly consistent between the
papers, a few difference do arise, and the section `Common symbols and
subscripts' is provided in the frontmatter to alleviate confusion. Particular
care should be taken with the symbols x and z; both can refer to the
coordinate parallel to the magnetic field line, but in papers where z is used
for this purpose x tends to have another definition. In the wrapper text the
choice of symbols is generally chosen to reflect those in the corresponding
paper.
Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results
(2023)
Objective
The objective was to evaluate clinical outcome and safety of arthroscopic, autologous minced cartilage implantation for acetabular cartilage lesions observed during hip arthroscopy to treat femoroacetabular impingement syndrome (FAIS).
Design
Eleven male patients, average age: 29.4 ± 5.4 years, average body mass index (BMI): 24.2 ± 2.2 kg/m2, scheduled for hip arthroscopy due to FAIS accompanied by an acetabular cartilage lesion were included in the case series. Cartilage tissue was harvested and minced from the loose cartilage flap at the chondrolabral lesion by arthroscopic shaver, augmented with autologous conditioned plasma, implanted into the defect, and fixated by autologous thrombin. Concomitant interventions were performed as indicated. The patients were evaluated preoperatively and at 24-month follow-up, using the International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) pain score and by magnetic resonance imaging (MRI) using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) grading scale at the 2-year follow-up.
Results
The defect size was on average 3.5 cm2 (1.5-4.5 cm2). From preoperatively to 2 years postoperatively, the iHOT-12 significantly improved from 50.2 ± 18 to 86.5 ± 19 (P < 0.0001), and pain score decreased from 5.6 ± 1.8 to 1.0 ± 1.5 (P < 0.0001) on the Visual Analog Scale pain score. Regarding functional outcome and pain, 10 of the 11 patients and all patients reached the minimal clinically important difference (MCID), respectively. The postoperative average MOCART score was 87.2 (± 9.2). No adverse events or reoperations were observed.
Conclusions
Arthroscopic, autologous minced cartilage implantation for treating full-thickness acetabular cartilage lesions in FAIS shows statistically and clinically significant improvement at short-term follow-up.
Background:
Minced cartilage implantation (MCI) has seen a renaissance in recent years. In this evolved technique, human articular cartilage is harvested with an arthroscopic shaver, augmented with platelet-rich plasma (PRP), and implanted with autologous thrombin. This modified technique combines the possibility of cell-based surgical cartilage repair with a minimally invasive autologous 1-step procedure. However, evidence on cell survival and preserved function after shaver-based mincing and PRP supplementation is limited.
Purpose:
To evaluate the effects of arthroscopic shaver mincing and augmentation with PRP on human cartilage tissue.
Study Design:
Controlled laboratory study.
Methods:
Standardized samples were taken from 12 donors during autologous MCI. A comparison of cell outgrowth, cell viability, proliferation capacity, and ability to produce extracellular matrix–specific proteoglycans after chondrogenic redifferentiation was made between cartilage taken by curettage from the border of the cartilage defect, cartilage tissue minced by an arthroscopic shaver, and cartilage tissue minced by an arthroscopic shaver that was additionally augmented with autologous PRP.
Results:
There was no difference between all 3 groups in terms of cell outgrowth or proliferation capacity. Metabolic activity relative to the cell number of chondrocytes isolated from shaver-minced cartilage was higher compared with chondrocytes isolated from cartilage that was derived by curettage or shaver-minced cartilage that was augmented with PRP. After chondrogenic stimulation, the normalized proteoglycan content was higher in spheroids of cells derived from shaver-minced cartilage augmented with PRP than in spheroids of cells derived from curettage. A high correlation of cell outgrowth, proliferation capacity, and viability between isolated cells from all 3 groups taken from an individual donor was observed.
Conclusion:
Chondrocytes isolated from human cartilage tissue that was harvested and minced with an arthroscopic shaver remained viable and proliferative. The augmentation of shaver-minced cartilage with PRP led to the enhanced proteoglycan production of chondrogenic spheroids in vitro, pointing toward the development of a cartilage-specific extracellular matrix. This in vitro study yields promising results regarding the use of an arthroscopic shaver and augmentation with PRP in the context of MCI.
Clinical Relevance:
Knowledge that shaver mincing and augmentation with PRP are feasible for processing articular cartilage during MCI is highly relevant for surgical cartilage repair.
Introduction: Vessel-associated retinal diseases are a major cause of blindness and severe visual impairment. The identification of appropriate biomarkers is of great importance to better anticipate disease progression and establish more targeted treatment options. MicroRNAs (miRNAs) are short, single-stranded, noncoding ribonucleic acids that are involved in the posttranscriptional regulation of gene expression through hybridization with messenger RNA. The expression of certain miRNAs can be different in patients with pathological processes and can be used for the detection and differentiation of various diseases. In this study, we investigate to what extent previously in vitro identified miRNAs are present as cell-free circulating miRNAs in the serum and vitreous of human patients with and without vessel-associated retinal diseases. Methods: Relative quantification by quantitative real-time polymerase chain reaction was used to analyze miRNA expression in patients with vessel-associated retinal diseases such as age-related macular degeneration (AMD), diabetic retinopathy (DR), and retinal vein occlusion compared with control patients. Results: In serum samples, miR-29a-3p and miR-192-5p showed increased expression in patients with neovascular AMD relative to control patients. Similarly, miR-335-5p, miR-192-5p, and miR-194-5p showed increased expression in serum from patients with proliferative DR. In vitreous samples, miR-100-5p was decreased in patients with proliferative DR. Differentially expressed miRNAs showed good diagnostic accuracy in receiver operating characteristic (ROC) and area under the ROC curve analysis. Conclusion: The miRNAs investigated in this study may have the potential to serve as biomarkers for vessel-associated retinal diseases. Combining multiple miRNAs may enhance the predictive power of the analysis.
In future fusion reactors disruptions must be avoided at all costs. Disruptions due to the density limit (DL) are typically described by the power-independent Greenwald scaling. Recently, a power dependence of the disruptive DL was predicted by several authors (Zanca et al 2019 Nucl. Fusion 59 126011; Giacomin et al 2022 Phys. Rev. Lett. 128 185003; Singh and Diamond 2022 Plasma Phys. Control. Fusion 64 084004; Stroth et al 2022 Nucl. Fusion 62 076008; Brown and Goldston 2021 Nucl. Mater. Energy 27 101002). It is investigated whether this increases the operational range of the tokamak. Increasing the heating power in the L-mode can induce an L-H transition, and therefore a power-dependent DL and the L-H transition cannot be considered independently. The different models are tested on a data base for separatrix parameters at the separatrix of ASDEX Upgrade and compared with the concept (SepOS) presented in Eich and Manz (2021 Nucl. Fusion 61 086017). The disruptive separatrix density scales with the power ne ∝ P0.38±0.08 in good agreement to all models. Also the back transition from high to low (H-L) confinement shows an approximately Greenwald scaling with an additional power dependence ne ∝ P0.4 according to the SepOS concept. For future devices operating at much higher heating power such a power scaling may allow operation at much higher separatrix densities than are common in H-mode operation. Preconditions to extrapolation for future devices are discussed.
The pulse length dependence of a reactive high power impulse magnetron sputtering (HiPIMS) discharge with a tungsten cathode in an argon+oxygen gas mixture gas was investigated. The HiPIMS discharge is operated with a variable pulse length of 20–500 µs. Discharge current measurements, optical emission spectroscopy of neutral Ar, O, and W lines, and energy-resolved ion mass spectrometry are employed. A pronounced dependence of the discharge current on pulse length is noted while the initial discharge voltage is maintained constant. Energy-resolved mass spectrometry shows that the oxygen-to-tungsten (O+/W+) and the tungsten oxide-to-tungsten (WO+/W+) ion ratio decreases with pulse length due to target cleaning. Simulation results employing the SDTrimSP program show the formation of a non-stoichiometric sub-surface compound layer of oxygen which depends on the impinging ion composition and thus on the pulse length.
Semiosis is the process in which a sign unfolds its effect—the meaning that humans ‘suddenly’ see in acts, objects or facts. The semiotic tenet is applied to the event and the question of why we narrate it. The graphics are dedicated to the author’s contribution: ‘The event and its consequences: a semiotic analysis.’
The current study analyzes the trajectory of the goose vowel in Received Pronunciation (RP) over ten decades (1920s-2010s). Recordings of eighty-seven RP speakers were transcribed in ELAN, and vowel tokens were extracted by FAVE, measuring F1 and F2 values at the midpoint. Showing the life-cycle of a sound change from start to (almost) completion, the results confirm that goose-fronting has been an active sound change for many decades in RP, with F2 starting to increase in the middle of the twentieth century and accelerated changes in the 1970s and the 2010s. We observe similar predictor strengths of linguistic factors as in previous studies. The results are interpreted in light of the social changes in the social composition of the RP group in the second part of the twentieth century, involving increased dialect contact.
Properties of self-excited dust acoustic waves under the influence of active compression of the dust particle system were experimentally studied in the laboratory and under microgravity conditions (parabolic flight). Ground based laboratory experiments clearly show that wave properties can be manipulated by changing the discharge volume, its aspect ratio, and thus the dust particle density. Complementary experiments under microgravity conditions, performed to exclude the effects of gravity inflicted sedimentation and anisotropic behavior, were less conclusive due to residual fluctuations in the planes acceleration indicating the need for a better microgravity environment. A theoretical model, using plasma parameters obtained from particle-in-cell simulations as input, supports the experimental findings. It shows that the waves can be described as a new observation of the dust acoustic mode, which demonstrates their generic character.
This article is the first to show that gender shapes the degree to which legislators use formal mechanisms to oversee government activities. Extensive scholarly work has analysed the use of oversight instruments, especially regarding who monitors whom. Whether, how, and why the conformity of men and women with institutional roles differs, has not yet received scholarly attention. We hypothesise that women become more active than men in overseeing the executive when in opposition while reducing their monitoring activities even more strongly than men when in government because of different social roles ascribed to men and women as well as differences in risk aversity between sexes. We analyse panel data for three oversight tools from the German Bundestag between 1949 and 2013 to test this proposition. Our findings imply that characteristics of political actors influence even a strongly institutionalised process as oversight and further clarify the gender bias in political representation.
Objective: In acute pancreatitis (AP), bacterial translocation and subsequent infection of pancreatic necrosis are the main risk factors for severe disease and late death. Understanding how immunological host defence mechanisms fail to protect the intestinal barrier is of great importance in reducing the mortality risk of the disease. Here, we studied the role of the Treg/Th17 balance for maintaining the intestinal barrier function in a mouse model of severe AP.
Design: AP was induced by partial duct ligation in C57Bl/6 or DEREG mice, in which regulatory T-cells (Treg) were depleted by intraperitoneal injection of diphtheria toxin. By flow cytometry, functional suppression assays and transcriptional profiling we analysed Treg activation and characterised T-cells of the lamina propria as well as intraepithelial lymphocytes (IELs) regarding their activation and differentiation. Microbiota composition was examined in intestinal samples as well as in murine and human pancreatic necrosis by 16S rRNA gene sequencing.
Results: The prophylactic Treg-depletion enhanced the proinflammatory response in an experimental mouse model of AP but stabilised the intestinal immunological barrier function of Th17 cells and CD8+/γδTCR+ IELs. Treg depleted animals developed less bacterial translocation to the pancreas. Duodenal overgrowth of the facultative pathogenic taxa Escherichia/Shigella which associates with severe disease and infected necrosis was diminished in Treg depleted animals.
Conclusion: Tregs play a crucial role in the counterbalance against systemic inflammatory response syndrome. In AP, Treg-activation disturbs the duodenal barrier function and permits translocation of commensal bacteria into pancreatic necrosis. Targeting Tregs in AP may help to ameliorate the disease course.
With high prevalence and mortality, myocardial infarction constitutes a social and economic burden in Germany and worldwide. Current guidelines for MI treatment require prompt reperfusion to salvage heart tissue and minimize short- and long-term complications. However, there are currently no treatments available to attenuate reperfusion injury. Ischemic as well as pharmacological post-conditioning have been identified as important clinical strategies to improve outcome. Membrane stabilizers, like Poloxamer 188 (P188), have been shown to improve myocardial ischemia reperfusion (IR) injury and mitochondrial function but have not yet been proven to directly offer mitochondrial protection. Mitochondrial function is crucial for cardiomyocyte function, and mitochondrial dysfunction plays an important role in myocardial injury.
In this study, hearts from 79 Sprague Dawley rats were isolated and perfused ex-vivo with oxygenated Krebs Buffer for 20 min before 30 min of no-flow ischemia. Hearts were reperfused for 10 min with Krebs buffer or 1 mM P188. Cardiac mitochondria were isolated with 1 mM P188 vs 1 mM polyethylene glycol (PEG) vs vehicle by differential centrifugation. Mitochondrial function was assessed as adenosine triphosphate (ATP) synthesis, oxygen consumption and calcium retention for complex I and II substrates of the respiratory chain.
An improvement of myocardial function with 10 min P188 post-conditioning could not be shown. Direct mitochondrial protection of P188 or PEG could not be observed in this model either. Further research is needed to ascertain whether P188 has a direct protective effect on mitochondria and, if so, on what pathways of IR injury it acts.
In den Weltmeeren findet rund die Hälfte der jährlichen globalen Kohlenstofffixierung statt, davon ein großer Anteil in küstennahen Regionen. Hier kommt es zu wiederkehrenden saisonalen Algenblüten, die durch eine zeitlich begrenzte explosionsartige Vermehrung von Mikroalgen (hauptsächlich Diatomeen und Coccolithophoren) charakterisiert sind. Vor allem Frühjahrsblüten (März-Mai) haben aufgrund ihrer zeitlichen und räumlichen Vorhersagbarkeit einen hohen Stellenwert als Modellsysteme, anhand deren sich der Kohlenstoffkreislauf der Meere untersuchen lässt.
Mikroalgen produzieren eine große Vielfalt an Makromolekülen, die für die mit ihnen vergesellschafteten Bakterien als Nahrungsgrundlage dienen. Besonders im Fokus stehen hier die für den Kohlenstoffkreislauf relevanten Polysaccharide. Im Gegensatz zu anderen natürlichen Makromolekülen wie DNA oder Proteinen können Polysaccharide aus vielen verschiedenen Monomeren mit unterschiedlichsten Bindungen bestehen. Zusätzlich finden sich an diesen Zuckermonomeren viele Modifikationen wie Acetylierungen, Methylierungen oder Sulfatierungen, die die Komplexität weiter erhöhen. Diese Variabilität bedingt eine hohe strukturelle und funktionale Diversität. So können Polysaccharide Speicherstoffe, Zellwandbestandteile oder Teile der extrazellulären Matrix darstellen.
Komplementär hierzu besitzen Polysaccharid-verwertende Bakterien entsprechend komplexe, enzymatische Abbaumechanismen. Besonders hervorzuheben sind hier die Bakterien des Phylums Bacteroidota, die sich in verschiedensten Nischen auf den Abbau von Polysacchariden spezialisiert haben. Sie finden sich in Bodenproben, als Teil der menschlichen Darmflora, oder eben auch als bedeutende Begleiter von Algenblüten.
Bacteroidota (und in marinen Systemen hauptsächlich die zu ihnen gehörenden Flavobakterien) besitzen zum Abbau diverser Polysaccharide sogenannte Polysaccharide utilization loci (PULs), genomische Inseln, die alle notwendigen Proteine zur Aufnahme und Abbau eines bestimmten Polysaccharids codieren. Hierzu gehören hochspezifische Enzyme (Carbohydrate-active enzymes, CAZymes), transkriptionelle Regulatoren sowie Transportersysteme, die initial gespaltene Oligosaccharide über die Membran in das Bakterium transportieren, wo sie von weiteren Enzymen vollständig abgebaut werden. Diese Co-Lokalisation der benötigten Gene und deren gemeinsame Regulation stellt einen enormen Selektionsvorteil der Bacteroidota dar und ist der Grund, warum sie, ähnlich wie Algen, einer jährlich wiederkehrenden Sukzession folgen, die sich gut untersuchen lässt.Die Forschungsartikel, die Teil dieser Doktorarbeit sind, untersuchen das Zusammenspiel von Polysaccharid-produzierenden Algen mit den Bakterien, die sie abbauen, aber auch darauf basierende Beziehungen der Bakterien untereinander. Die erste Publikation beschäftigt sich mit dem weit verbreiteten Speicherpolysaccharid α-Glucan, für das der Großteil der blütenbegleitenden Bakterien einen spezifischen aktiven PUL besitzt. Eine Untersuchung der in der Blüte vorhandenen Algenarten bestätigte, dass die Blüte von β-Glucan-produzierenden Algen dominiert wird. Da Bakterien aber selbst α-Glucane als Speicherpolysaccharide verwenden, konnte gezeigt werden, dass nicht die Algen selbst, sondern die Bakterien Hauptproduzent dieser Polysaccharide während einer Phytoplanktonblüte sind. Bakterielle Proteine, die dem Abbau von Algen-β-Glucan und dem daraus folgenden Aufbau von bakteriellem α-Glucan dienen, waren in Umweltproben und in Laborkulturen unter ähnlichen Bedingungen abundant. Die Untersuchung von extrahiertem bakteriellem Polysaccharid bewies, dass dieses nicht nur α-Glucan enthält, sondern dass dieses Polysaccharid auch in der Lage war, α-Glucan PULs mariner Bakterien zu induzieren. Hier zeigte sich ein innerhalb des marinen Kohlenstoffkreislaufs bisher wenig berücksichtigter Kreislauf, indem Bakterien Polysaccharide anderer Bakterien nutzen, die z.B. durch Viren lysiert wurden.
Die anderen zwei Artikel dieser Arbeit befassen sich mit dem Abbau von Zellwandpolysacchariden durch blütenassoziierte Modellbakterien. In einer der Studien wird detailliert der Abbau eines β-Mannans (ein Polysaccharid das hauptsächlich aus dem Monosaccharid Mannose besteht) durch ein Bakterium des Genus Muricauda beschrieben. Die PUL-Struktur dieses Bakteriums kam in mehreren anderen Phytoplanktonblüten-assoziierten Bakterien vor. Diese Beobachtung wies darauf hin, dass es sich hier um ein Mannan mit zusätzlichen Galactose- und Glucose-Substitutionen handelte. Proteom-Untersuchungen bestätigten, dass das Bakterium derartige Substrate unter Induktion des β-Mannan-PULs nutzen können. β-Mannan konnte durch Antikörpermarkierung in Blütenproben sowie spezifischen Mikroalgenarten (Chaetoceros, Coscinodiscus) nachgewiesen werden. Die in dieser Publikation charakterisieren β-Mannan-PUL-codierten Enzyme waren in der Lage, dieses Signal zu löschen, was bewies, dass Muricauda sp. Mannan-basierte Zellwandpolysaccharide bestimmter Arten von Mikroalgen abbauen kann.
Die dritte Studie geht näher auf den Abbau von Xylanen (bestehend aus Xylose) durch ein blütenassoziiertes Bakterium des Genus Flavimarina ein. In diesem Bakterium wurden anhand der enthaltenen Xylanasen zwei putative Xylan-PULs annotiert. Wachstumsexperimente und Proteom-Untersuchungen zeigten, dass einer dieser PULs hauptsächlich bei Wachstum auf Glucoronoxylan induziert wird, während der andere PUL aufArabinoxylane stärker reagierte. Untersuchung der PUL-CAZymes bestätigte diese Ergebnisse durch Charakterisierung mehrerer Xylanasen sowie Glucoronidasen und Arabinofuranosidasen. Zusätzlich codierten beide PULs für Esterasen, die eine Modifikation der natürlichen Substrate durch Acetylierungen oder Methylierungen nahelegen. Da all diese Merkmale von terrestrischen Xylanen geteilt werden und in Blütenproben aus Küstennahen Regionen Xylane nachgewiesen wurden, ist es möglich, dass Bakterien aus solchen Regionen sowohl Xylane terrestrischen Ursprungs (z.B. durch Flusseinspeisung) sowie marinen Ursprungs abbauen können.
Our study examined whether potentially critical indications from depression questionnaires, interviews, and single items on suicidal ideation among partici-pants in a large prospective population-based study are related to short-term sui-cides within one year. For this purpose, we studied the association between (a) the severity of depressive symptoms according to the M-CIDI and the PHQ-9, BDI-II, and CID-S depression screening and (b) elevated scores on single sui-cidal ideation items and mortality according to claims databases.
In the baseline cohort, the frequency of depressive symptoms measured by CID-S was 12.90% (SHIP-START-0). The frequency for “Moderate” to “Severe de-pression” measured by the PHQ-9 (≥ 10 points) and BDI-II (≥ 20 points) ques-tionnaires ranged from 5.40% (SHIP-LEGENDE) to 8.80% (SHIP-TREND Morbid-ity follow-up). The 1-month prevalence of unipolar depression, measured by the M-CIDI in SHIP LEGENDE, was 2.31%.
Between 5.90% (SHIP-TREND Morbidity follow-up) and 6.60% (SHIP-LEGENDE) of respondents showed a certain degree of suicidal ideation in the two weeks preceding the assessment, according to BDI-II and PHQ-9.
Our results show the high frequency of depressive symptoms in the study region, with women being affected more frequently than men, especially in the higher categories. Furthermore, women were more frequently affected by suicidal idea-tion, although this difference was not evident in the highest categories.
There was one potential suicide in the year after a SHIP examination.
From our results, we cannot conclude that severe self-reported symptoms from depression questionnaires should be reported back to participants of an obser-vational population-based study to prevent suicide deaths within one year.