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Whereas interspecific associations receive considerable attention in evolutionary, behavioural and ecological literature, the proximate bases for these associations are usually unknown. This in particular applies to associations between vertebrates with invertebrates. The West-African savanna frog Phrynomantis microps lives in the underground nest of ponerine ants (Paltothyreus tarsatus). The ants usually react highly aggressively when disturbed by fiercely stinging, but the frog is not attacked and lives unharmed among the ants. Herein we examined the proximate mechanisms for this unusual association. Experiments with termites and mealworms covered with the skin secretion of the frog revealed that specific chemical compounds seem to prevent the ants from stinging. By HPLC-fractionation of an aqueous solution of the frogs' skin secretion, two peptides of 1,029 and 1,143 Da were isolated and found to inhibit the aggressive behaviour of the ants. By de novo sequencing using tandem mass spectrometry, the amino acid sequence of both peptides consisting of a chain of 9 and 11 residues, respectively, was elucidated. Both peptides were synthesized and tested, and exhibited the same inhibitory properties as the original frog secretions. These novel peptides most likely act as an appeasement allomone and may serve as models for taming insect aggression.
In der vorliegenden Studie wird aufbauend auf 54 pflanzensoziologischen Aufnahmen eine ökologische und syntaxonomische Gliederung der Heidenelken-reichen, bodensauren Magerrasen der Medebacher Bucht (Ostrand des Rheinischen Schiefergebirges) vorgenommen. Die Aufnahmen werden dem Thymo pulegioidis-Festucetum ovinae Oberd. 1957, einem artenreichen, mesophilen Silikat-Magerrasen mit einer lückigen Feldschicht zugeordnet. Bei den Lebensformen überwiegen Hemikryptophyten und Therophyten. Dominante Strategietypen sind Arten mit intermediärer Strategie (CSR), Konkurrenz- und Ruderal-Strategen. Das Thymo-Festucetum kann in zwei floristisch-soziologisch und ökologisch deutlich getrennte Subassoziationen untergliedert werden. Die entscheidenden Standortfaktoren für diese Unterteilung sind die Bodenfeuchte und Nutzung. Die frischeren Standorte der Subassoziation von Achillea millefolium werden meist beweidet oder einschürig gemäht. Besiedelt werden ebene bis kaum geneigte flachgründige Braunerden. Die kryptogamenreichen Bestände der Subassoziation von Viola arvensis siedeln auf Skeletthumusböden oft stark geneigter Hänge und liegen brach. Das Thymo-Festucetum ist meist mosaikartig mit anderen Gesellschaften verzahnt. Auf frischeren und nährstoffreicheren Standorten wird die Subassoziation von Achillea millefolium durch Gesellschaften des Wirtschaftsgrünlandes abgelöst. Die Subassoziation von Viola arvensis steht in Kontakt zu Gesellschaften der Calluno-Ulicetea. Gegenüber den Ausbildungen auf Lockersubstraten im Tiefland fehlen dem Thymo-Festucetum auf Festgestein in den Mittelgebirgen eigene Höhen-Differenzialarten. Der ökologisch wirksamste edaphische Unterschied scheint die größere Dynamik mit teilweiser Übersan- dung der Pflanzen auf den Sandstandorten im Tiefland zu sein. Zur Pflege der Bestände der Achillea millefolium-Subassoziation des Thymo-Festucetum in der Medebacher Bucht ist eine extensive Beweidung die optimale Pflegemaßnahme. Die bevorzugte Form der Nutzung sollte die Hütehaltung mit Schafen und einzelnen Ziegen sein. Für die Bestände der Viola arvensis-Subassoziation erscheint keine regelmäßige Nutzung notwendig. Vielmehr sind unregelmäßige Störungen anzustreben.
The success of social insects is largely intertwined with their highly advanced chemical communication system that facilitates recognition and discrimination of species and nest-mates, recruitment, and division of labor. Hydrocarbons, which cover the cuticle of insects, not only serve as waterproofing agents but also constitute a major component of this communication system. Two cryptic Crematogaster species, which share their nest with Camponotus ants, show striking diversity in their cuticular hydrocarbon (CHC) profile. This mutualistic system therefore offers a great opportunity to study the genetic basis of CHC divergence between sister species. As a basis for further genome-wide studies high-quality genomes are needed. Here, we present the annotated draft genome for Crematogaster levior A. By combining the three most commonly used sequencing techniques—Illumina, PacBio, and Oxford Nanopore—we constructed a high-quality de novo ant genome. We show that even low coverage of long reads can add significantly to overall genome contiguity. Annotation of desaturase and elongase genes, which play a role in CHC biosynthesis revealed one of the largest repertoires in ants and a higher number of desaturases in general than in other Hymenoptera. This may provide a mechanistic explanation for the high diversity observed in C. levior CHC profiles.
Hypoxia-induced long non-coding RNA Malat1 is dispensable for renal ischemia/reperfusion-injury
(2018)
Renal ischemia-reperfusion (I/R) injury is a major cause of acute kidney injury (AKI). Non-coding RNAs are crucially involved in its pathophysiology. We identified hypoxia-induced long non-coding RNA Malat1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) to be upregulated in renal I/R injury. We here elucidated the functional role of Malat1 in vitro and its potential contribution to kidney injury in vivo. Malat1 was upregulated in kidney biopsies and plasma of patients with AKI, in murine hypoxic kidney tissue as well as in cultured and ex vivo sorted hypoxic endothelial cells and tubular epithelial cells. Malat1 was transcriptionally activated by hypoxia-inducible factor 1-α. In vitro, Malat1 inhibition reduced proliferation and the number of endothelial cells in the S-phase of the cell cycle. In vivo, Malat1 knockout and wildtype mice showed similar degrees of outer medullary tubular epithelial injury, proliferation, capillary rarefaction, inflammation and fibrosis, survival and kidney function. Small-RNA sequencing and whole genome expression analysis revealed only minor changes between ischemic Malat1 knockout and wildtype mice. Contrary to previous studies, which suggested a prominent role of Malat1 in the induction of disease, we did not confirm an in vivo role of Malat1 concerning renal I/R-injury.
Background: Lung disease phenotype varies widely even in the F508del (homozygous) genotype. Leukocyte-driven inflammation is important for pulmonary disease pathogenesis in cystic fibrosis (CF). Blood cytokines correlate negatively with pulmonary function in F508del homozygous patients, and gap junction proteins (GJA) might be related to the influx of blood cells into the lung and influence disease course. We aimed to assess the relationship between GJA1/GJA4 genotypes and the clinical disease phenotype. Methods: One-hundred-and-sixteen homozygous F508del patients (mean age 27 years, m/f 66/50) were recruited from the CF centers of Bonn, Frankfurt, and Amsterdam. Sequence analysis was performed for GJA1 and GJA4. The clinical disease course was assessed over 3 years using pulmonary function tests, body mass index, Pseudomonas aeruginosa colonization, diabetes mellitus, survival to end-stage lung disease, blood and sputum inflammatory markers. Results: Sequence analysis revealed one clinically relevant single nucleotide polymorphism. In this GJA4 variant (rs41266431), homozygous G variant carriers (n = 84/116; 72.4%) had poorer pulmonary function (FVC% pred: mean 78/86, p < 0.040) and survival to end-stage lung disease was lower (p < 0.029). The frequency of P. aeruginosa colonization was not influenced by the genotype, but in those chronically colonized, those with the G/G genotype had reduced pulmonary function (FVC% pred: mean 67/80, p < 0.049). Serum interleukin-8 (median: 12.4/6.7 pg/ml, p < 0.052) and sputum leukocytes (2305/437.5 pg/ml, p < 0.025) were higher for the G/G genotype. Conclusions: In carriers of the A allele (27.6%) the GJA4 variant is associated with significantly better protection against end-stage lung disease and superior pulmonary function test results in F508del homozygous patients. This SNP has the potential of a modifier gene for phenotyping severity of CF lung disease, in addition to the CFTR genotype.
Clinical Trial Registration: The study was registered with ClinicalTrials.gov, number NCT04242420, retrospectively on January 24th, 2020.
Invasive treatment of NSTEMI patients in German chest pain units – evidence for a treatment paradox
(2018)
Background: Patients with non ST-segment elevation myocardial infarction (NSTEMI) represent the largest fraction of patients with acute coronary syndrome in German Chest Pain units. Recent evidence on early vs. selective percutaneous coronary intervention (PCI) is ambiguous with respect to effects on mortality, myocardial infarction (MI) and recurrent angina. With the present study we sought to investigate the prognostic impact of PCI and its timing in German Chest Pain Unit (CPU) NSTEMI patients.
Methods and results: Data from 1549 patients whose leading diagnosis was NSTEMI were retrieved from the German CPU registry for the interval between 3/2010 and 3/2014. Follow-up was available at median of 167 days after discharge. The patients were grouped into a higher (Group A) and lower risk group (Group B) according to GRACE score and additional criteria on admission. Group A had higher Killip classes, higher BNP levels, reduced EF and significant more triple vessel disease (p < 0.001). Surprisingly, patients in group A less frequently received early diagnostic catheterization and PCI. While conservative management did not affect prognosis in Group B, higher-risk CPU-NSTEMI patients without PCI had a significantly worse survival.
Conclusions: The present results reveal a substantial treatment gap in higher-risk NSTEMI patients in German Chest Pain Units. This treatment paradox may worsen prognosis in patients who could derive the largest benefit from early revascularization.
A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process β-decay chains. These nuclei are attributed to the p and rp process.
For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections.
The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
Auf der Basis von 127 pflanzensoziologischen Aufnahmen aus dem Jahr 2004 werden naturnahe bodensaure Buchenwälder entlang eines Transektes vom Bergischen Land bis ins Niederrheinische Tiefland erfasst und syntaxonomisch gegliedert. Untermauert mit den Ergebnissen bodenökologischer Analysen wird die syntaxonomische Gliederung diskutiert und mit Hilfe multivariater Analyseverfahren auf ihre Aussagekraft hin geprüft. Durch die Untersuchung von Flächen entlang eines Transektes zeigt sich, dass bodensaure Buchenwälder der Tieflagen als eigenständige Assoziation differenzierbar sind. Sie gehören zum Periclymeno-Fagetum, während das Luzulo-Fagetum in der Ilex aquifolium-reichen Ausbildung im Bergischen Land vorherrscht. Daraus ergibt sich als Konsequenz, dass die Tiefland-Buchenwälder in Anbetracht des Fehlens der Charakterart Luzula luzuloides nicht nur als Vikariante eines weiter zu fassenden Luzulo-Fagetum zu verstehen sind.
Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.