91 research outputs found
Structure and functioning of oribatid mite communities along an elevational gradient of tropical mountain rainforests
Tropical mountain rain forests are among the most species rich regions in the world. The RBSF (Reserva Biológica San Francisco) area in southern Ecuador is a hotspot of biodiversity. To characterise this exceptional high diversity it is essential to investigate the complex interactions between the organisms and their abiotic environment. A number of groups of organisms, including birds, moths, orchids and mosses, have been investigated, whereas knowledge on others, including soil invertebrates, is minute. This study focuses on (1) the characterisation of the hidden diversity of soil animal species, in particular that of oribatid mites (Oribatida), (2) the composition and function of soil microarthropods including their trophic relationship, (3) decomposition processes including altitude (temperature, moisture), litter type (low and high quality) and microarthropods (small and large mesh of litterbags). (1) At the study site 193 species of 48 families of oribatid mites were determined which is high but compared to temperate forest ecosystems not extraordinary divers. The proportion of not described species is assumed to be around 40 %. Nine new species of ptyctimous oribatid mites were described. Many species are restricted to tropical regions indicating specific community structures in the tropics. Furthermore, the oribatid mite community differed along the elevation gradient from 1850 to 2270 m indicating distinct oribatid mite communities at different altitudes. (2) The high diversity of oribatid mites and decomposer soil animals in general, is one of the great riddles in soil ecology. Whereas in deciduous forests the soil microarthropods are well characterised, taxonomical knowledge in tropical rainforests and especially in mountain regions is low. One aim of this study was to investigate the microarthropod soil community. The density of microarthropods and oribatid mite communities at three horizons (L, F/H, Ah) and on the bark of adjacent trees along an elevation gradient (1850, 2020, 2200 and 2270 m) in the RBSF forest were studied. Oribatid mites were the most abundant group followed by Collembola and Gamasina. The compared to temperate forests generally low number of microarthropods declined with elevation in the order 1850 > 2020 > 2270 ~ 2200 m and with soil depth (L, F/H, Ah). Microarthropods on bark were less abundant than in soil. Declining numbers of soil microarthropods with altitude is concluded to be due to harsh abiotic conditions (e.g. lower temperatures, waterlogging, solar radiation). Low microbial biomass and resource quality presumably also contribute to the low abundances of soil microarthropods. The trophic structure of 32 species and potential basal food resources (litter of Graffenrieda emarginata) was investigated by analysing natural variations in stable isotope ratios (15N/14N; 13C/12C). The results indicate that the soil food web is similar to that of temperate forests and spans about four trophic levels. Primary decomposers, i.e. litter feeding species, were rare, potentially reflecting low litter quality. A large number of ‘decomposer’ animals were in fact predatory or necrophagous, suggesting that various putative decomposer soil animal species (especially in oribatid mites) presumably feed on other soil invertebrates, in particular nematodes or animal carcasses. (3) We studied leaf litter decomposition of two abundant tree species with higher and lower litter quality (Graffenrieda emarginata, Purdiaea nutans) and a mixture of both in a litterbag field experiment at two altitudes (1850 and 2280 m). Litter quality was measured as microbial biomass and N content. Decomposition rates at the studied tropical mountain rain forest were generally low (average of 32 % y-1). The slow decomposition rates may have been due to low litter quality (e.g. high C-to-N ratios) but also due to low temperatures. Litter generally decomposed slower at higher elevation supporting our assumption that temperature is a major driving force for litter decomposition at our study sites and indicating that organic matter accumulates at high altitudes. P. nutans litter after 2 and 6 months of exposure decomposed slower than that of G. emarginata, but not at the end of the experiment, after twelve months. We suggest that litter chemistry affect decomposition mainly at early stages of decomposition. After 12 months the mixture of G. emarginata and P. nutans litter decomposed significantly faster than both single litter types indicating that combining the two litter types accelerates decomposition processes ('non-additive effect'). Soil microarthropods contributed little to decomposition processes. Microbial biomass and density of microarthropods in the litterbags were higher at 1850 than at 2280 m indicating higher biological activity at lower altitudes. Species composition was similar in both litter types supporting previous findings that the structure of soil decomposer microarthropod communities is little affected by litter type
Gene-Gene Interaction between APOA5 and USF1: Two Candidate Genes for the Metabolic Syndrome
Objective: The metabolic syndrome, a major cluster of risk factors for cardiovascular diseases, shows increasing prevalence worldwide. Several studies have established associations of both apolipoprotein A5 (APOA5) gene variants and upstream stimulatory factor 1 (USF1) gene variants with blood lipid levels and metabolic syndrome. USF1 is a transcription factor for APOA5. Methods: We investigated a possible interaction between these two genes on the risk for the metabolic syndrome, using data from the German population-based KORA survey 4 (1,622 men and women aged 55-74 years). Seven APOA5 single nucleotide polymorphisms (SNPs) were analyzed in combination with six USF1 SNPs, applying logistic regression in an additive model adjusting for age and sex and the definition for metabolic syndrome from the National Cholesterol Education Program's Adult Treatment Panel III (NCEP (AIII)) including medication. Results: The overall prevalence for metabolic syndrome was 41%. Two SNP combinations showed a nominal gene-gene interaction (p values 0.024 and 0.047). The effect of one SNP was modified by the other SNP, with a lower risk for the metabolic syndrome with odds ratios (ORs) between 0.33 (95% CI = 0.13-0.83) and 0.40 (95% CI = 0.15-1.12) when the other SNP was homozygous for the minor allele. Nevertheless, none of the associations remained significant after correction for multiple testing. Conclusion: Thus, there is an indication of an interaction between APOA5 and USF1 on the risk for metabolic syndrome
Association between variations in the TLR4 gene and incident type 2 diabetes is modified by the ratio of total cholesterol to HDL-cholesterol
<p>Abstract</p> <p>Background</p> <p>Toll-like receptor 4 (TLR4), the signaling receptor for lipopolysaccharides, is an important member of the innate immunity system. Since several studies have suggested that type 2 diabetes might be associated with changes in the innate immune response, we sought to investigate the association between genetic variants in the <it>TLR4 </it>gene and incident type 2 diabetes.</p> <p>Methods</p> <p>A case-cohort study was conducted in initially healthy, middle-aged subjects from the MONICA/KORA Augsburg studies including 498 individuals with incident type 2 diabetes and 1,569 non-cases. Seven SNPs were systematically selected in the <it>TLR4 </it>gene and haplotypes were reconstructed.</p> <p>Results</p> <p>The effect of <it>TLR4 </it>SNPs on incident type 2 diabetes was modified by the ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C). In men, four out of seven <it>TLR4 </it>variants showed significant interaction with TC/HDL-C after correction for multiple testing (p < 0.01). The influence of the minor alleles of those variants on the incidence of type 2 diabetes was observed particularly for male patients with high values of TC/HDL-C. Consistent with these findings, haplotype-based analyses also revealed that the effect of two haplotypes on incident type 2 diabetes was modified by TC/HDL-C in men (p < 10<sup>-3</sup>). However, none of the investigated variants or haplotypes was associated with type 2 diabetes in main effect models without assessment of effect modifications.</p> <p>Conclusion</p> <p>We conclude that minor alleles of several <it>TLR4 </it>variants, although not directly associated with type 2 diabetes might increase the risk for type 2 diabetes in subjects with high TC/HDL-C. Additionally, our results confirm previous studies reporting sex-related dissimilarities in the development of type 2 diabetes.</p
Density and community structure of soil- and bark-dwelling microarthropods along an altitudinal gradient in a tropical montane rainforest
Microarthropod communities in the soil and on the bark of trees were investigated along an elevation gradient (1,850, 2,000, 2,150, 2,300 m) in a tropical montane rain forest in southern Ecuador. We hypothesised that the density of microarthropods declines with depth in soil and increases with increasing altitude mainly due to the availability of resources, i.e. organic matter. In addition, we expected bark and soil communities to differ strongly, since the bark of trees is more exposed to harsher factors. In contrast to our hypothesis, the density of major microarthropod groups (Collembola, Oribatida, Gamasina, Uropodina) was generally low and decreased with altitude. However, as we predicted the density of each of the groups decreased with soil depth. Density of microarthropods on tree bark was lower than in soil. Overall, 43 species of oribatid mites were found, with the most abundant higher taxa being Poronota, pycnonotic Apheredermata, Mixonomata and Eupheredermata. The oribatid mite community on bark did not differ significantly from that in soil. The number of oribatid mite species declined with altitude (24, 23, 17 and 13 species at 1,850, 2,000, 2,150 and 2,300 m, respectively). Rarefaction curves indicate that overall about 50 oribatid mite species are to be expected along the studied altitudinal gradient. Results of this study indicate (1) that microarthropods may be limited by the quality of resources at high altitudes and by the amount of resources at deeper soil layers, and (2) that the bark of trees and the soil are habitats of similar quality for oribatid mites
Meta-analysis of genome-wide association studies from the CHARGE consortium identifies common variants associated with carotid intima media thickness and plaque
Carotid intima media thickness (cIMT) and plaque determined by ultrasonography are established measures of subclinical atherosclerosis that each predicts future cardiovascular disease events. We conducted a meta-analysis of genome-wide association data in 31,211 participants of European ancestry from nine large studies in the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. We then sought additional evidence to support our findings among 11,273 individuals using data from seven additional studies. In the combined meta-analysis, we identified three genomic regions associated with common carotid intima media thickness and two different regions associated with the presence of carotid plaque (P < 5 × 10 -8). The associated SNPs mapped in or near genes related to cellular signaling, lipid metabolism and blood pressure homeostasis, and two of the regions were associated with coronary artery disease (P < 0.006) in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) consortium. Our findings may provide new insight into pathways leading to subclinical atherosclerosis and subsequent cardiovascular events
The German National Pandemic Cohort Network (NAPKON): rationale, study design and baseline characteristics
Schons M, Pilgram L, Reese J-P, et al. The German National Pandemic Cohort Network (NAPKON): rationale, study design and baseline characteristics. European Journal of Epidemiology . 2022.The German government initiated the Network University Medicine (NUM) in early 2020 to improve national research activities on the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic. To this end, 36 German Academic Medical Centers started to collaborate on 13 projects, with the largest being the National Pandemic Cohort Network (NAPKON). The NAPKON's goal is creating the most comprehensive Coronavirus Disease 2019 (COVID-19) cohort in Germany. Within NAPKON, adult and pediatric patients are observed in three complementary cohort platforms (Cross-Sectoral, High-Resolution and Population-Based) from the initial infection until up to three years of follow-up. Study procedures comprise comprehensive clinical and imaging diagnostics, quality-of-life assessment, patient-reported outcomes and biosampling. The three cohort platforms build on four infrastructure core units (Interaction, Biosampling, Epidemiology, and Integration) and collaborations with NUM projects. Key components of the data capture, regulatory, and data privacy are based on the German Centre for Cardiovascular Research. By April 01, 2022, 34 university and 40 non-university hospitals have enrolled 5298 patients with local data quality reviews performed on 4727 (89%). 47% were female, the median age was 52 (IQR 36-62-) and 50 pediatric cases were included. 44% of patients were hospitalized, 15% admitted to an intensive care unit, and 12% of patients deceased while enrolled. 8845 visits with biosampling in 4349 patients were conducted by April 03, 2022. In this overview article, we summarize NAPKON's design, relevant milestones including first study population characteristics, and outline the potential of NAPKON for German and international research activities.Trial registration https://clinicaltrials.gov/ct2/show/NCT04768998 . https://clinicaltrials.gov/ct2/show/NCT04747366 . https://clinicaltrials.gov/ct2/show/NCT04679584. © 2022. The Author(s)
Decreased plasma phospholipid concentrations and increased acid sphingomyelinase activity are accurate biomarkers for community-acquired pneumonia
Background: There continues to be a great need for better biomarkers and host-directed treatment targets for
community-acquired pneumonia (CAP). Alterations in phospholipid metabolism may constitute a source of small
molecule biomarkers for acute infections including CAP. Evidence from animal models of pulmonary infections and
sepsis suggests that inhibiting acid sphingomyelinase (which releases ceramides from sphingomyelins) may reduce
end-organ damage.
Methods: We measured concentrations of 105 phospholipids, 40 acylcarnitines, and 4 ceramides, as well as acid
sphingomyelinase activity, in plasma from patients with CAP (n=29, sampled on admission and 4 subsequent time
points), chronic obstructive pulmonary disease exacerbation with infection (COPD, n=13) as a clinically important
disease control, and 33 age- and sex-matched controls.
Results: Phospholipid concentrations were greatly decreased in CAP and normalized along clinical improvement.
Greatest changes were seen in phosphatidylcholines, followed by lysophosphatidylcholines, sphingomyelins and cer‑
amides (three of which were upregulated), and were least in acylcarnitines. Changes in COPD were less pronounced,
but also difered qualitatively, e.g. by increases in selected sphingomyelins. We identifed highly accurate biomark‑
ers for CAP (AUC≤0.97) and COPD (AUC≤0.93) vs. Controls, and moderately accurate biomarkers for CAP vs. COPD
(AUC≤0.83), all of which were phospholipids. Phosphatidylcholines, lysophosphatidylcholines, and sphingomyelins
were also markedly decreased in S. aureus-infected human A549 and diferentiated THP1 cells. Correlations with
C-reactive protein and procalcitonin were predominantly negative but only of mild-to-moderate extent, suggesting
that these markers refect more than merely infammation. Consistent with the increased ceramide concentrations,
increased acid sphingomyelinase activity accurately distinguished CAP (fold change=2.8, AUC=0.94) and COPD
(1.75, 0.88) from Controls and normalized with clinical resolution Conclusions: The results underscore the high potential of plasma phospholipids as biomarkers for CAP, begin to
reveal diferences in lipid dysregulation between CAP and infection-associated COPD exacerbation, and suggest that
the decreases in plasma concentrations are at least partially determined by changes in host target cells. Furthermore,
they provide validation in clinical blood samples of acid sphingomyelinase as a potential treatment target to improve
clinical outcome of CAP
Genetic Association Study Identifies HSPB7 as a Risk Gene for Idiopathic Dilated Cardiomyopathy
Dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background. Monogenic forms of DCM are observed in families with mutations located mostly in genes encoding structural and sarcomeric proteins. However, strong evidence suggests that genetic factors also affect the susceptibility to idiopathic DCM. To identify risk alleles for non-familial forms of DCM, we carried out a case-control association study, genotyping 664 DCM cases and 1,874 population-based healthy controls from Germany using a 50K human cardiovascular disease bead chip covering more than 2,000 genes pre-selected for cardiovascular relevance. After quality control, 30,920 single nucleotide polymorphisms (SNP) were tested for association with the disease by logistic regression adjusted for gender, and results were genomic-control corrected. The analysis revealed a significant association between a SNP in HSPB7 gene (rs1739843, minor allele frequency 39%) and idiopathic DCM (p = 1.06×10−6, OR = 0.67 [95% CI 0.57–0.79] for the minor allele T). Three more SNPs showed p < 2.21×10−5. De novo genotyping of these four SNPs was done in three independent case-control studies of idiopathic DCM. Association between SNP rs1739843 and DCM was significant in all replication samples: Germany (n = 564, n = 981 controls, p = 2.07×10−3, OR = 0.79 [95% CI 0.67–0.92]), France 1 (n = 433 cases, n = 395 controls, p = 3.73×10−3, OR = 0.74 [95% CI 0.60–0.91]), and France 2 (n = 249 cases, n = 380 controls, p = 2.26×10−4, OR = 0.63 [95% CI 0.50–0.81]). The combined analysis of all four studies including a total of n = 1,910 cases and n = 3,630 controls showed highly significant evidence for association between rs1739843 and idiopathic DCM (p = 5.28×10−13, OR = 0.72 [95% CI 0.65–0.78]). None of the other three SNPs showed significant results in the replication stage
Towards a Reusable First Stage Demonstrator: CALLISTO - Technical Progresses & Challenges
In order to investigate the capabilities of a reusable launch system, JAXA, CNES and DLR have jointly initiated the project CALLISTO ("Cooperative Action Leading to Launcher Innovation for Stage Toss-back Operations"). The goal of this cooperation is to launch, recover and reuse a first stage demonstrator to increase the maturity of technologies necessary for future operational reusable launch vehicles (RLV) and to build up know-how on such vehicles under operational and developmental aspects.
As the project has now turned into the detailed design phase, significant technical progresses have been made in definition, analysis and testing of systems and subsystems. The CALLISTO vehicle itself constitutes a subscale vertical take-off vertical landing (VTVL) stage with an overall length of 13.5 m and a take-off mass of less than 4 tons, which is propelled by a throttleable LOX/LH2 engine. It is capable to perform up to 10 consecutive flights during the planned flight campaign in French Guiana. Globally, the development effort on this system is equally shared between the three project partners.
This paper presents the recent achievements in development of the key technologies for the reusable launch vehicle. While the design of critical subsystems has reached PDR level, detailed analyses and first breadboard tests have been performed successfully. These results are presented and discussed within the perimeter of the CALLISTO development roadmap. Possible technical challenges are indicated and their resolution methods are examined. Finally, the upcoming development steps are described which are foreseen to move forward to the qualification and maiden flight campaign
Genome-wide and gene-centric analyses of circulating myeloperoxidase levels in the charge and care consortia
Increased systemic levels of myeloperoxidase (MPO) are associated with the risk of coronary artery disease (CAD). To identify the genetic factors that are associated with circulating MPO levels, we carried out a genome-wide association study (GWAS) and a gene-centric analysis in subjects of European ancestry and African Americans (AAs). A locus on chromosome 1q31.1 containing the complement factor H (CFH) gene was strongly associated with serum MPO levels in 9305 subjects of European ancestry (lead SNP rs800292; P = 4.89 × 10−41) and in 1690 AA subjects (rs505102; P = 1.05 × 10−8). Gene-centric analyses in 8335 subjects of European ancestry additionally identified two rare MPO coding sequence variants that were associated with serum MPO levels (rs28730837, P = 5.21 × 10−12; rs35897051, P = 3.32 × 10−8). A GWAS for plasma MPO levels in 9260 European ancestry subjects identified a chromosome 17q22 region near MPO that was significantly associated (lead SNP rs6503905; P = 2.94 × 10−12), but the CFH locus did not exhibit evidence of association with plasma MPO levels. Functional analyses revealed that rs800292 was associated with levels of complement proteins in serum. Variants at chromosome 17q22 also had pleiotropic cis effects on gene expression. In a case–control analysis of ∼80 000 subjects from CARDIoGRAM, none of the identified single-nucleotide polymorphisms (SNPs) were associated with CAD. These results suggest that distinct genetic factors regulate serum and plasma MPO levels, which may have relevance for various acute and chronic inflammatory disorders. The clinical implications for CAD and a better understanding of the functional basis for the association of CFH and MPO variants with circulating MPO levels require further study
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