Gut-associated functions are favored during microbiome assembly across a major part of C. elegans life

The microbiome expresses a variety of functions that influence host biology. The range of functions depends on the microbiome's composition, which can change during the host's lifetime due to neutral assembly processes, host-mediated selection, and environmental conditions. To date, the exact dynamics of microbiome assembly, the underlying determinants, and the effects on host-associated functions remain poorly understood. Here, we used the nematode Caenorhabditis elegans and a defined community of fully sequenced, naturally associated bacteria to study microbiome dynamics and functions across a major part of the worm's lifetime of hosts under controlled experimental conditions. Bacterial community composition initially shows strongly declining levels of stochasticity, which increases during later time points, suggesting selective effects in younger animals as opposed to more random processes in older animals. The adult microbiome is enriched in genera Ochrobactrum and Enterobacter compared to the direct substrate and a host-free control environment. Using pathway analysis, metabolic, and ecological modeling, we further find that the lifetime assembly dynamics increase competitive strategies and gut-associated functions in the host-associated microbiome, indicating that the colonizing bacteria benefit the worm. Overall, our study introduces a framework for studying microbiome assembly dynamics based on stochastic, ecological, and metabolic models, yielding new insights into the processes that determine host-associated microbiome composition and function.

IMPORTANCE

The microbiome plays a crucial role in host biology. Its functions depend on the microbiome composition that can change during a host's lifetime. To date, the dynamics of microbiome assembly and the resulting functions still need to be better understood. This study introduces a new approach to characterize the functional consequences of microbiome assembly by modeling both the relevance of stochastic processes and metabolic characteristics of microbial community changes. The approach was applied to experimental time-series data obtained for the microbiome of the nematode Caenorhabditis elegans across the major part of its lifetime. Stochastic processes played a minor role, whereas beneficial bacteria as well as gut-associated functions enriched in hosts. This indicates that the host might actively shape the composition of its microbiome. Overall, this study provides a framework for studying microbiome assembly dynamics and yields new insights into C. elegans microbiome functions.

The archaeome in metaorganism research, with a focus on marine models and their bacteria-archaea interactions

Metaorganism research contributes substantially to our understanding of the interaction between microbes and their hosts, as well as their co-evolution. Most research is currently focused on the bacterial community, while archaea often remain at the sidelines of metaorganism-related research. Here, we describe the archaeome of a total of eleven classical and emerging multicellular model organisms across the phylogenetic tree of life. To determine the microbial community composition of each host, we utilized a combination of archaea and bacteria-specific 16S rRNA gene amplicons. Members of the two prokaryotic domains were described regarding their community composition, diversity, and richness in each multicellular host. Moreover, association with specific hosts and possible interaction partners between the bacterial and archaeal communities were determined for the marine models. Our data show that the archaeome in marine hosts predominantly consists of Nitrosopumilaceae and Nanoarchaeota, which represent keystone taxa among the porifera. The presence of an archaeome in the terrestrial hosts varies substantially. With respect to abundant archaeal taxa, they harbor a higher proportion of methanoarchaea over the aquatic environment. We find that the archaeal community is much less diverse than its bacterial counterpart. Archaeal amplicon sequence variants are usually host-specific, suggesting adaptation through co-evolution with the host. While bacterial richness was higher in the aquatic than the terrestrial hosts, a significant difference in diversity and richness between these groups could not be observed in the archaeal dataset. Our data show a large proportion of unclassifiable archaeal taxa, highlighting the need for improved cultivation efforts and expanded databases.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

While numerous health-beneficial interactions between host and microbiota have been identified, there is still a lack of targeted approaches for modulating these interactions. Thus, we here identify precision prebiotics that specifically modulate the abundance of a microbiome member species of interest. In the first step, we show that defining precision prebiotics by compounds that are only taken up by the target species but no other species in a community is usually not possible due to overlapping metabolic niches. Subsequently, we use metabolic modeling to identify precision prebiotics for a two-member Caenorhabditis elegans microbiome community comprising the immune-protective target species Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71. We experimentally confirm four of the predicted precision prebiotics, L-serine, L-threonine, D-mannitol, and γ-aminobutyric acid, to specifically increase the abundance of MYb11. L-serine was further assessed in vivo, leading to an increase in MYb11 abundance also in the worm host. Overall, our findings demonstrate that metabolic modeling is an effective tool for the design of precision prebiotics as an important cornerstone for future microbiome-targeted therapies.IMPORTANCEWhile various mechanisms through which the microbiome influences disease processes in the host have been identified, there are still only few approaches that allow for targeted manipulation of microbiome composition as a first step toward microbiome-based therapies. Here, we propose the concept of precision prebiotics that allow to boost the abundance of already resident health-beneficial microbial species in a microbiome. We present a constraint-based modeling pipeline to predict precision prebiotics for a minimal microbial community in the worm Caenorhabditis elegans comprising the host-beneficial Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71 with the aim to boost the growth of MYb11. Experimentally testing four of the predicted precision prebiotics, we confirm that they are specifically able to increase the abundance of MYb11 in vitro and in vivo. These results demonstrate that constraint-based modeling could be an important tool for the development of targeted microbiome-based therapies against human diseases.

The intricate triangular interaction between protective microbe, pathogen and host determines fitness of the metaorganism

The microbiota shapes host biology in numerous ways. One example is protection against pathogens, which is likely critical for host fitness in consideration of the ubiquity of pathogens. The host itself can affect abundance of microbiota or pathogens, which has usually been characterized in separate studies. To date, however, it is unclear how the host influences the interaction with both simultaneously and how this triangular interaction determines fitness of the host-microbe assemblage, the so-called metaorganism. To address this current knowledge gap, we focused on a triangular model interaction, consisting of the nematode Caenorhabditis elegans, its protective symbiont Pseudomonas lurida MYb11 and its pathogen Bacillus thuringiensis Bt679. We combined the two microbes with C. elegans mutants with altered immunity and/or microbial colonization, and found that (i) under pathogen stress, immunocompetence has a larger influence on metaorganism fitness than colonization with the protective microbe; (ii) in almost all cases, MYb11 still improves fitness; and (iii) disruption of p38 MAPK signalling, which contributes centrally to immunity against Bt679, completely reverses the protective effect of MYb11, which further reduces nematode survival and fitness upon infection with Bt679. Our study highlights the complex interplay between host, protective microbe and pathogen in shaping metaorganism biology.

Effect of Indian clubbell exercises on cricket fast bowlers' shoulder kinematics

Background

The glenohumeral joint's rotational range of motion (ROM) and muscle strength are essential to execute the cricket bowling action. Performing shoulder rotation exercises may increase the rotator cuff muscle strength and rotational ROM.

Objectives

The aim of this study was to test the effect of a six-week exercise programme on shoulder rotational ROM and muscle strength.

Methods

Twenty-one healthy male cricket fast bowlers were recruited, ranked and pair-matched on initial shoulder rotator muscle strength and assigned to either a shoulder exercise (SE) group or cricket training (CT) only group. The SE group incorporated Indian clubbell exercises in addition to their cricket training.

Results

Bowlers in both groups displayed a large increase on the dominant shoulder's internal rotation (IR) ROM, but only the SE group's bowlers displayed ROM improvements (p<0.001) bilaterally for both internal and external rotation. The CT group's fast bowler's non-dominant shoulder IR ROM significantly decreased (p=0.02) during the six weeks. Between groups, only the SE group's bowler's internal rotator muscle strength improved (p<0.001) bilaterally. The observed kinematic changes were statistically significantly greater at a 5% level for the SE group's bowlers (bilateral internal rotators muscle strength, non-dominant shoulder IR ROM and horizontal adduction ROM).

Conclusion

Maintenance of the shoulder's rotational ROM and muscle strength is vital for a fast bowler. Cricket bowlers who perform regular clubbell exercises might increase their shoulder's ROM and internal rotator cuffs' muscle strength, which may aid in stabilising their glenohumeral joint while bowling.

Host and microbiome jointly contribute to environmental adaptation

Most animals and plants have associated microorganisms, collectively referred to as their microbiomes, which can provide essential functions. Given their importance, host-associated microbiomes have the potential to contribute substantially to adaptation of the host-microbiome assemblage (the "metaorganism"). Microbiomes may be especially important for rapid adaptation to novel environments because microbiomes can change more rapidly than host genomes. However, it is not well understood how hosts and microbiomes jointly contribute to metaorganism adaptation. We developed a model system with which to disentangle the contributions of hosts and microbiomes to metaorganism adaptation. We established replicate mesocosms containing the nematode Caenorhabditis elegans co-cultured with microorganisms in a novel complex environment (laboratory compost). After approximately 30 nematode generations (100 days), we harvested worm populations and associated microbiomes, and subjected them to a common garden experiment designed to unravel the impacts of microbiome composition and host genetics on metaorganism adaptation. We observed that adaptation took different trajectories in different mesocosm lines, with some increasing in fitness and others decreasing, and that interactions between host and microbiome played an important role in these contrasting evolutionary paths. We chose two exemplary mesocosms (one with a fitness increase and one with a decrease) for detailed study. For each example, we identified specific changes in both microbiome composition (for both bacteria and fungi) and nematode gene expression associated with each change in fitness. Our study provides experimental evidence that adaptation to a novel environment can be jointly influenced by host and microbiome.

Irradiation Dose to the Swallowing Muscles Impacts Nutritional Status in Head and Neck Cancer Patients: The Prospective Randomized HEADNUT Trial

PURPOSE/OBJECTIVE(S)

To evaluate the influence of radiation dose on swallowing muscles and associated side effects as well as on nutritional status in patients with head and neck cancer undergoing primary or adjuvant (chemo)radiotherapy.

MATERIALS/METHODS

Between 2018 and 2020, sixty-one patients were prospectively randomized into the so-called HEADNUT-trial (HEAD and neck cancer patients undergoing NUTritional intervention). Follow-up was continued until 2022. Contouring of the swallowing apparatus included and the swallowing muscles with the superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeal muscle and the inlet of the esophagus. Nutritional status was assessed by bioelectrical impedance analysis (BIA) at the beginning and the end of radiotherapy. The post-therapeutic nutritional status was evaluated by the BIA-derived FFMI (fat-free mass index; kg/m²). Malnutrition was assumed at FFMI values of <15 (♀) and <17 (♂) kg/m². To find differences between dosimetric parameters in well- and malnourished patients, Mann-Whitney-U-test was used. To estimate the relationship between malnutrition and its influencing variables a logistic regression model was built.

RESULTS

The following structures differed between well- and malnourished patients at the end of therapy: icm (Dmean, V40Gy (%), V50Gy (%), V60Gy (%)) and cricopharyngeal muscle (V40Gy (%)). After entering these parameters into a multivariable logistic regression model icm Dmean (b = -0.12; Exp(b) = 0.88; 95%-CI: 0.78-1.0; p = 0.06) and icm V40Gy (%) (b = 0.06; Exp(b) = 1.07; 95%-CI: 1-1.13; p = 0.04) proved to be independent predictors of malnutrition. We only determined the cut-off value for icm V40Gy (%) since it was the only parameter which met p<0.05. The optimal cut-off value for the predictor V40Gy (%) based on the Youden Index was 85.6%.

CONCLUSION

Adherence to dose constraints for the swallowing apparatus may prevent malnutrition in head and neck cancer patients at the end of therapy. Specifically, we suggest an icm V40Gy (%) of more than 86% being predictive for nutritional complications.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

The microbiome is increasingly receiving attention as an important modulator of host health and disease. However, while numerous mechanisms through which the microbiome influences its host have been identified, there is still a lack of approaches that allow to specifically modulate the abundance of individual microbes or microbial functions of interest. Moreover, current approaches for microbiome manipulation such as fecal transfers often entail a non-specific transfer of entire microbial communities with potentially unwanted side effects. To overcome this limitation, we here propose the concept of precision prebiotics that specifically modulate the abundance of a microbiome member species of interest. In a first step, we show that defining precision prebiotics by compounds that are only taken up by the target species but no other species in a community is usually not possible due to overlapping metabolic niches. Subsequently, we present a metabolic modeling network framework that allows us to define precision prebiotics for a two-member C. elegans microbiome model community comprising the immune-protective Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71. Thus, we predicted compounds that specifically boost the abundance of the host-beneficial MYb11, four of which were experimentally validated in vitro (L-serine, L-threonine, D-mannitol, and γ-aminobutyric acid). L-serine was further assessed in vivo, leading to an increase in MYb11 abundance also in the worm host. Overall, our findings demonstrate that constraint-based metabolic modeling is an effective tool for the design of precision prebiotics as an important cornerstone for future microbiome-targeted therapies.

The nematode Caenorhabditis elegans and diverse potential invertebrate vectors predominantly interact opportunistically

Some small animals migrate with the help of other, more mobile animals (phoresy) to leave short-lived and resource-poor habitats. The nematode Caenorhabditis elegans lives in ephemeral habitats such as compost, but has also been found associated with various potential invertebrate vectors. Little research has been done to determine if C. elegans is directly attracted to these invertebrates. To determine whether C. elegans is attracted to compounds and volatile odorants of invertebrates, we conducted chemotaxis experiments with the isopods Porcellio scaber, Oniscus asellus, and Armadillidium sp. and with Lithobius sp. myriapods, Drosophila melanogaster fruit flies, and Arion sp. slugs as representatives of natural vectors. Because phoresy is an important escape strategy in nature, especially for dauer larvae of C. elegans, we examined the attraction of the natural C. elegans isolate MY2079 in addition to the laboratory-adapted strain N2 at the dauer and L4 stage. We found that DMSO washing solution of Lithobius sp. and the odor of live D. melanogaster attracted C. elegans N2 L4 larvae. Surprisingly, the natural isolate MY2079 was not attracted to any invertebrate during either the dauer or L4 life stages and both C. elegans strains were repelled by various compounds from O. asellus, P. scaber, Armadillidium sp., Lithobius sp., and Arion sp. feces. We hypothesize that this is due to defense chemicals released by the invertebrates. Although compounds from Lithobius sp. and D. melanogaster odorants were mildly attractive, the lack of attraction to most invertebrates suggests a predominantly opportunistic association between C. elegans and invertebrate vectors.

Prognostic impact of echocardiographic derived precapillary wedge pressure and pulmonary vascular resistances in patients with heart failure

Background

A reliable echocardiographic algorithm for the estimation of precapillary wedge pressure (PCWP) and pulmonary vascular resistances (PVR) has been recently validated by our group in a large cohort of patients undergoing right heart catheterization (RHC) (1). Those metrics may add relevant clinical and prognostic information in patients with heart failure (HF).

Objective

To assess the clinical/prognostic significance of echocardiographic derived PCWP and PVR in a large cohort of chronic HF patients on modern treatments.

Methods

Outpatients with chronic HF with either reduced (≤40%) or mildly reduced LVEF (41–49%) underwent a thorough clinical multiparametric assessment and were followed-up for a composite endpoint of cardiac death, appropriate ICD shock, or first HF hospitalization.

Results

Out of 1,483 patients prospectively enrolled (70±12 years, 73% males, 42% ischemic etiology, LVEF 35±8%), PCWP (16.4±5.8 mmHg) was elevated (&gt;15 mmHg) in 53% of cases, while PVR (1.7±0.7) was elevated (&gt;3 WU) in 6% of cases. Of the latter group, most (92%) had also elevated PCWP. Patients with increased PCWP were older, had a higher heart rate and lower cardiac output, showed a higher degree of left and right chamber remodeling, had a higher neurohormonal activation, worse renal function, worse functional capacity and ventilatory efficiency on effort (all p&lt;0.001). Those patients with high PCWP and PVR showed higher heart rate and pulmonary pressures, lower cardiac output, and right ventricular function, higher neurohormonal activation, lower functional capacity and ventilatory efficiency on effort compared to patients with high PCWP but normal PVR (all p&lt;0.01). The optimal prognostic cut-point was identified for both PCWP (16.2 mmHg) and PVR (2 WU) by log-rank maximal likelihood ratio. Over a median follow-up of 22 (8–37) months, both measures significantly stratified patients for the risk of the primary endpoint at Kaplan-Meier analysis (log-rank 92.9, p&lt;0.001 for PCWP; log-rank 17.3, p&lt;0.001 for PVR). At multivariable Cox regression analysis (adjusted for age, sex, ischemic HF etiology, renal function, LVEF, and NT-proBNP), PCWP (hazard ratio, HR 1.77 [95% CI 1.30–2.40], p&lt;0.001) but not PVR (HR 1.15 [95% CI 0.88–1.51], p=0.31) remained an independent predictor of the primary outcome.

Conclusion

The estimation of PCWP and PVR by echocardiography add relevant clinical and prognostic information and may help in the decision making in patients with HF.

Funding Acknowledgement

Type of funding sources: None.

Valve disease in cardiac amyloidosis: an echocardiographic score

Background

Cardiac amyloidosis (CA) may affect all cardiac structures, including the valves.

Methods

From 423 patients undergoing a diagnostic workup for CA we selected 2 samples of 20 patients with amyloid transthyretin (ATTR-) or light-chain (AL-) CA, and age- and sex-matched controls. We chose 31 echocardiographic items related to the mitral, aortic and tricuspid valves, giving a value of 1 to each abnormal item.

Results

Patients with ATTR-CA displayed more often a shortened/hidden and restricted posterior mitral valve leaflet (PMVL), thickened mitral chordae tendineae and aortic stenosis than those with AL-CA, and less frequent PMVL calcification than matched controls. Score values were 15.8 (13.6–17.4) in ATTR-CA, 11.0 (9.3–14.9) in AL-CA, 12.8 (11.1–14.4) in ATTR-CA controls, and 11.0 (9.1–13.0) in AL-CA controls (p=0.004 for ATTR- vs. AL-CA, 0.009 for ATTR-CA vs. their controls, and 0.461 for AL-CA vs. controls). Area under the curve values to diagnose ATTR-CA were 0.782 in patients with ATTR-CA or matched controls, and 0.773 in patients with LV hypertrophy.

Conclusions

Patients with ATTR-CA have a prominent impairment of mitral valve structure and function, and higher score values. The valve score is quite effective in identifying patients with ATTR-CA among patients with CA or unexplained hypertrophy.

Funding Acknowledgement

Type of funding sources: None.

Clinical and prognostic significance of left ventricular outflow tract velocity time integral (LVOT-VTI) in patients with chronic heart failure

Background

The echocardiographic evaluation of cardiac output relies on the product of the flow across the left ventricular outflow tract (LVOT), estimated through its velocity time integral (LVOT-VTI), and its cross-sectional area, estimated through the formula πr2. Considering the geometrical assumption behind such formula, LVOT-VTI has been proposed as a more reproducible surrogate of cardiac systolic function and showed prognostic value in the critical care setting. However, the role of such measure in patients with chronic heart failure (HF) remains unexplored.

Objective

To assess the clinical and prognostic significance of LVOT-VTI in a contemporary cohort of patients with chronic HF.

Methods

Outpatients with chronic HF with a LV ejection fraction &lt;50% were prospectively enrolled to undergo a clinical, echocardiographic, and biohumoral assessment, and were followed-up for the endpoint of all-cause death.

Results

Finally, 971 patients were enrolled (71±12 years, 72% men, 50% ischemic etiology, LVEF 35±9%). Most patients showed a NYHA class I-II (74%) and were treated with ACE-inhibitors/ARBs or ARNI (81%), beta-blockers (95%), and mineralocorticoid receptor antagonists (71%). Patients were distinguished in three subgroups according to LVOT-VTI tertiles &lt;19 (n=324), 19–24 (n=324), or ≥24 (n=323). Compared with the other two subgroups, patients with LVOT-VTI &lt;19 showed worse NYHA class, lower LVEF and tricuspid annular plane systolic excursion (TAPSE), and higher E/e', left atrial volume index (LAVi), estimated systolic pulmonary arterial pressure (sPAP), and NT-proBNP concentration (all p&lt;0.001). No differences were observed as for patients' age, HF etiology, and therapies (all p&gt;0.05). Over a median follow-up of 22 (9–34) months, 103 (11%) patients met the primary endpoint. LVOT-VTI significantly stratified the risk of death, observing 65 (20%), 21 (7%), and 17 (5%) events across the subgroups with values &lt;19, 19–24, or ≥24 (log-rank 33, p&lt;0.001). At multivariable regression analysis, LVOT-VTI &lt;19 (HR 2.06 [95% 1.21–3.49], p=0.008), but not LVEF &lt;30% (p=0.614) was an independent predictor of all-cause death in a model adjusted for age, sex, ischemic etiology, renal function, hemoglobin, E/e', LAVi, TAPSE, sPAP, and NT-proBNP.

Conclusion

LVOT-VTI is associated with disease severity and is a strong predictor of all-cause death in patients with chronic HF.

Funding Acknowledgement

Type of funding sources: None.

C42 MULTI–CHAMBER SPECKLE TRACKING IMAGING AND DIAGNOSTIC VALUE OF LEFT ATRIAL STRAIN IN CARDIAC AMYLOIDOSIS

Background

Amyloid deposits in all cardiac chambers, impairing their function. We investigated for the first time if a speckle–tracking echocardiography (STE) analysis extended to all 4 chambers might hold additive diagnostic value for CA and its subtypes (amyloid transthyretin [ATTR–] and light–chain [AL]–CA).

Methods

We evaluated 423 consecutive patients undergoing a diagnostic workup for CA in 2 referral centres from 2015 to 2020.

Results

CA was diagnosed in 261 patients (62%; ATTR–CA, n = 144, 34%; AL–CA, n = 117, 28%). Patients with CA had an impaired function of all cardiac chambers, particularly those with ATTR–CA. Peak left atrial longitudinal strain (LA–PALS) was the only STE parameter that predicted CA and ATTR–CA independent of laboratory and standard echocardiographic variables (Model 1). It also predicted ATTR–CA among patients with unexplained hypertrophy regardless of a diagnostic score (IWT score). Patients with either LA–PALS or LA–peak atrial contraction strain (PACS) in the first quartile (LA–PALS &lt;6.65% or LA–PACS &lt;3.62%) had an almost 4–fold higher likelihood of CA and ATTR–CA regardless of Model 1. Among patients with unexplained hypertrophy, those with LA–PALS or LA–PACS in the first quartile had an almost 9–fold higher likelihood of ATTR–CA irrespective of Model 1, and a 2–fold higher likelihood of ATTR–CA beyond the IWT score.

Conclusions

STE measures of all 4 chambers are abnormal in patients with CA, particularly in those with ATTR–CA. LA strain holds independent diagnostic significance. Among patients screened for CA, those with LA–PALS &lt;6.65% and/or LA–PACS &lt;3.62% have a high likelihood of CA and ATTR–CA.

P294 AN ECHOCARDIOGRAPHIC SCORE OF VALVE DISEASE IN PATIENTS WITH CARDIAC AMYLOIDOSIS

Background

Cardiac amyloidosis (CA) affects all cardiac structures, including the valves. We summarized the echocardiographic features of valve disease in a score.

Methods

From 423 patients undergoing a diagnostic workup for CA we selected 2 samples of 20 patients with amyloid transthyretin (ATTR–) or light–chain (AL–) CA, and selected age– and sex–matched controls. The Amyloid VAlve (AVA) score included 31 items related to the mitral, aortic and tricuspid valves (which can be properly assessed in standard echocardiograms), with a value of 1 for each abnormal item.

Results

Patients with ATTR–CA displayed more often a shortened/hidden and retracted posterior mitral valve leaflet (PMVL), thickened mitral chordae tendineae and aortic stenosis than those with AL–CA, and less frequent PMVL calcification than matched controls. Score values were 15.8 (interquartile interval 13.6–17.4) in ATTR–CA, 11.0 (9.3–14.9) in AL–CA, 12.8 (11.1–14.4) in ATTR–CA controls, and 11.0 (9.1–13.0) in AL–CA controls (p = 0.004 for ATTR– vs. AL–CA, 0.009 for ATTR–CA vs. their controls, and 0.461 for AL–CA vs. controls). We compared the AVA and two validated diagnostic scores (IWT and AMYLI). AUC values for the diagnosis of ATTR–CA were 0.782, 0.846 and 0.902, respectively, in patients with ATTR–CA or matched controls, and 0.773, 0.706 and 0.679 in patients with LV hypertrophy (n = 67, 84%) (all non–significant p values).

Conclusions

Patients with ATTR–CA have a prominent impairment of mitral valve structure and function, and higher score values. The AVA score is quite effective in identifying patients with ATTR–CA among patients with CA or with unexplained hypertrophy.

Preconditioning With Natural Microbiota Strain Ochrobactrum vermis MYb71 Influences Caenorhabditis elegans Behavior

In comparison with the standard monoxenic maintenance in the laboratory, rearing the nematode Caenorhabditis elegans on its natural microbiota improves its fitness and immunity against pathogens. Although C. elegans is known to exhibit choice behavior and pathogen avoidance behavior, little is known about whether C. elegans actively chooses its (beneficial) microbiota and whether the microbiota influences worm behavior. We examined eleven natural C. elegans isolates in a multiple-choice experiment for their choice behavior toward four natural microbiota bacteria and found that microbiota choice varied among C. elegans isolates. The natural C. elegans isolate MY2079 changed its choice behavior toward microbiota isolate Ochrobactrum vermis MYb71 in both multiple-choice and binary-choice experiments, in particular on proliferating bacteria: O. vermis MYb71 was chosen less than other microbiota bacteria or OP50, but only after preconditioning with MYb71. Examining escape behavior and worm fitness on MYb71, we ruled out pathogenicity of MYb71 and consequently learned pathogen avoidance behavior as the main driver of the behavioral change toward MYb71. The change in behavior of C. elegans MY2079 toward microbiota bacterium MYb71 demonstrates how the microbiota influences the worm's choice. These results might give a baseline for future research on host-microbiota interaction in the C. elegans model.

Integration of radiation oncology teaching in medical studies by German medical faculties due to the new licensing regulations : An overview and recommendations of the consortium academic radiation oncology of the German Society for Radiation Oncology (DEGRO)

The new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) will soon be passed by the Federal Council (Bundesrat) and will be implemented step by step by the individual faculties in the coming months. The further development of medical studies essentially involves an orientation from fact-based to competence-based learning and focuses on practical, longitudinal and interdisciplinary training. Radiation oncology and radiation therapy are important components of therapeutic oncology and are of great importance for public health, both clinically and epidemiologically, and therefore should be given appropriate attention in medical education. This report is based on a recent survey on the current state of radiation therapy teaching at university hospitals in Germany as well as the contents of the National Competence Based Learning Objectives Catalogue for Medicine 2.0 (Nationaler Kompetenzbasierter Lernzielkatalog Medizin 2.0, NKLM) and the closely related Subject Catalogue (Gegenstandskatalog, GK) of the Institute for Medical and Pharmaceutical Examination Questions (Institut für Medizinische und Pharmazeutische Prüfungsfragen, IMPP). The current recommendations of the German Society for Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) regarding topics, scope and rationale for the establishment of radiation oncology teaching at the respective faculties are also included.

Left atrial strain in cardiac amyloidosis

Background

Patients with cardiac amyloidosis (CA) display an enlarged and dysfunctional left atrium (LA), because of the effects of left ventricular (LV) diastolic and then systolic dysfunction, as well as the amyloid infiltration of LA wall. A single study reported impaired LA strain in CA, but differences among amyloid light-chain (AL) and transthyretin (ATTR) CA and the correlates of reduced LA strain have not been characterized.

Methods

We evaluated 426 consecutive patients undergoing a screening for suspected CA in 2 tertiary referral centres. Among them, 262 (61%) were diagnosed with CA (n=117 AL-CA, n=145 ATTR-CA). We measured peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS) from 4- and 2-chamber (4C, 2C) views, and correlated them with maximum and minimum LA volumes, E/e' ratio, and LV global longitudinal strain (GLS).

Results

LA strain was much more severely impaired in patients with ATTR-CA than those without CA, and to a lesser extent than those with AL-CA (Figure). LA volumes were larger in patients with ATTR-CA than those without CA (maximal LA volume, p=0.042; minimal LA volume, p&lt;0.001), and those with AL-CA (both volumes, p&lt;0.001). LA strain values were more closely correlated with minimal than maximal LA volumes, and patients with AL-CA displayed stronger correlations than those with ATTR-CA or without CA; for example, Spearman's rho values for 4C-PALS vs. minimal LA volume were 0.595, 0.481, and 0.462, respectively (all p&lt;0.001). Furthermore, LA strain correlated with E/e' in patients with AL-CA, but not in those with ATTR-CA: 4C-PALS vs. E/e', rho 0.406, p=0.001 (AL-CA), p=0.401 (ATTR-CA), and p=0.097 (no CA). Finally, LA strain correlated most closely with LV GLS in patients with AL-CA: 4C-PALS vs. LV GLS, rho 0.431, p&lt;0.001 (AL-CA), rho 0.401, p&lt;0.001 (ATTR-CA), rho 0.219, p=0.042 (no CA).

Conclusions

LA volume increase and reduced LA strain is particularly prominent in patients with ATTR-CA. Patients with AL-CA seem to display closer relationships between LA strain, size and haemodynamic load, possibly reflecting the most acute disease course, and lower time for amyloid deposition in the LA wall.

Funding Acknowledgement

Type of funding sources: None.

Reverse remodelling criteria to predict cardiovascular death in heart failure with reduced or mid-range ejection fraction

Aims

Reverse remodelling (RR) is the recovery from left ventricle (LV) dilatation and dysfunction. There are no established definitions of RR. We sought to identify RR criteria that better predicted cardiovascular death.

Methods and results

Forty-two studies used 25 criteria to define RR, most commonly (n=12) as LV end-systolic volume (LVESV) reduction ≥15%. We evaluated 927 patients with LV ejection fraction (LVEF) &lt;50% undergoing 2 echocardiograms within 12±2 months. Over a median 2.8-year follow-up after the second echocardiogram (1.3–4.9), 123 cardiovascular deaths occurred (13%). Model 1 included age, LVEF, N-terminal pro-B-type natriuretic peptide (NT-proBNP), ischaemic aetiology, cardiac resynchronization therapy (CRT), estimated glomerular filtration rate (eGFR), New York Heart Association (NYHA), and LVESV index (LVESVi), and Model 2 the validated 3C-HF score. Two RR criteria proved particularly effective in risk reclassification over Model 1 and Model 2: LVEF increase ≥1 category (severe [LVEF ≤30%], moderate [LVEF 31–40%], mild LV dysfunction [LVEF 41–55%] and normal LV function [LVEF ≥56%]), and LVEF increase &gt;10 U. The same 2 criteria yielded independent prognostic significance and improved reclassification also in patients with LVEF &lt;40% or LVEF ≤35%. LVEF increase ≥1 category and LVEF increase &gt;10 U displayed a stronger prognostic value than LVESV reduction ≥15%, both in the whole population and the subsets with LVEF &lt;40% or ≤35%.

Funding Acknowledgement

Type of funding sources: None.

Fungal quinones: diversity, producers, and applications of quinones from Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium

Quinones represent an important group of highly structurally diverse, mainly polyketide-derived secondary metabolites widely distributed among filamentous fungi. Many quinones have been reported to have important biological functions such as inhibition of bacteria or repression of the immune response in insects. Other quinones, such as ubiquinones are known to be essential molecules in cellular respiration, and many quinones are known to protect their producing organisms from exposure to sunlight. Most recently, quinones have also attracted a lot of industrial interest since their electron-donating and -accepting properties make them good candidates as electrolytes in redox flow batteries, like their often highly conjugated double bond systems make them attractive as pigments. On an industrial level, quinones are mainly synthesized from raw components in coal tar. However, the possibility of producing quinones by fungal cultivation has great prospects since fungi can often be grown in industrially scaled bioreactors, producing valuable metabolites on cheap substrates. In order to give a better overview of the secondary metabolite quinones produced by and shared between various fungi, mainly belonging to the genera Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium, this review categorizes quinones into families such as emodins, fumigatins, sorbicillinoids, yanuthones, and xanthomegnins, depending on structural similarities and information about the biosynthetic pathway from which they are derived, whenever applicable. The production of these quinone families is compared between the different genera, based on recently revised taxonomy. KEY POINTS: • Quinones represent an important group of secondary metabolites widely distributed in important fungal genera such as Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium. • Quinones are of industrial interest and can be used in pharmacology, as colorants and pigments, and as electrolytes in redox flow batteries. • Quinones are grouped into families and compared between genera according to the revised taxonomy.

Microbes to-go: slugs as source for Caenorhabditis elegans microbiota acquisition

Research on the Caenorhabditis elegans microbiota only recently started, with little known about how C. elegans acquires its microbiota. Slugs live in the same habitat as C. elegans and are known vectors for the worm. Hence, we wondered how the passage through a slug affects the C. elegans gut microbiota and whether worms can acquire bacteria from the slug. Using fluorescently labelled microbiota and 16S rRNA gene amplicon sequencing, we evaluated microbiota persistence and acquisition in C. elegans after slug passage. We compared C. elegans gut microbiomes isolated from wild-caught slugs to the microbiomes of worms after experimental slug passage to compare similarities and differences in microbiome composition. We found that microbiota persists in C. elegans while passing the slug gut and that worms simultaneously acquire additional bacteria species from the slug. Although the amplicon sequencing variant (ASV) richness of worms from the experiment did not exceed the richness of worms that naturally occur in slugs, we found a high number of shared ASVs indicating the importance of commonly associated microbiota. We demonstrate that C. elegans can take advantage of its passage through the slug by acquiring new potential microbiota without losing its native microbiota.