Barcoding of Central European Cryptops centipedes reveals large interspecific distances with ghost lineages and new species records from Germany and Austria (Chilopoda,Scolopendromorpha)

In order to evaluate the diversity of Central European Myriapoda species in the course of the German Barcode of Life project, 61 cytochrome c oxidase I sequences of the genus Cryptops Leach, 1815, a centipede genus of the order Scolopendromorpha, were successfully sequenced and analyzed. One sequence of Scolopendra cingulata Latreille, 1829 and one of Theatops erythrocephalus Koch, 1847 were utilized as outgroups. Instead of the expected three species (Cryptops parisi Brolemann, 1920; Cryptops anomalans Newport, 1844; Cryptops hortensis (Donovan, 1810)), analyzed samples included eight to ten species. Of the eight clearly distinguishable morphospecies of Cryptops, five (Cryptops parisi; Cryptops croaticus Verhoeff, 1931; Cryptops anomalans; Cryptops umbricus Verhoeff, 1931; Cryptops hortensis) could be tentatively determined to species level, while a further three remain undetermined (one each from Germany, Austria and Croatia, and Slovenia). Cryptops croaticus is recorded for the first time from Austria. A single specimen (previously suspected as being Cryptops anomalans), was redetermined as Cryptops umbricus Verhoeff, 1931, a first record for Germany. All analyzed Cryptops species are monophyletic and show large genetic distances from one another (p-distances of 13.7–22.2%). Clear barcoding gaps are present in lineages represented by >10 specimens, highlighting the usefulness of the barcoding method for evaluating species diversity in centipedes. German specimens formally assigned to Cryptops parisi are divided into three clades differing by 8.4–11.3% from one another; their intra-lineage genetic distance is much lower at 0–1.1%. The three clades are geographically separate, indicating that they might represent distinct species. Aside from Cryptops parisi, intraspecific distances of Cryptops spp. in Central Europe are low (<3.3%).     

Electrical resistance measurements on cerebral capillary endothelial cells — a new technique to study small surface areas

We present a new method which allows resistance measurements in selected cell monolayer areas with a size of less than one mm². Up to now cell-covered macroscopic filters with areas up to 5 cm² have been used giving reliable results only in the absence of inhomogeneities or contaminating cells. The new measuring device is posed on the microscope optic to allow an optical characterization of the measuring area and enables us to scan the cell-covered filter. This method has been applied to determine a reversible modulation of the tightness of intercellular contacts between epithelial or endothelial cells in culture. Tight junction resistance is modulated by Ca²⁺ and basic amino acids in cultured porcine cerebral microvascular endothelial cells that represent the blood-brain barrier.     

First results of the German Barcode of Life (GBOL) – Myriapoda project: Cryptic lineages in German Stenotaenia linearis (Koch, 1835) (Chilopoda,Geophilomorpha)

As part of the German Barcode of Life (GBOL) Myriapoda program, which aims to sequence the COI barcoding fragment for 2000 specimens of Germany’s 200 myriapod species in the near future, 44 sequences of the centipede order Geophilomorpha are analyzed. The analyses are limited to the genera Geophilus Leach, 1814 and Stenotaenia Koch, 1847 and include a total of six species. A special focus is Stenotaenia, of which 19 specimens from southern, western and eastern Germany could be successfully sequenced. The Stenotaenia data shows the presence of three to four vastly different (13.7–16.7% p-distance) lineages of the genus in Germany. At least two of the three lineages show a wide distribution across Germany, only the lineage including topotypes of Stenotaenia linearis shows a more restricted distribution in southern Germany. In a maximum likelihood phylogenetic analysis the Italian species Stenotaenia ‘sorrentina’ (Attems, 1903) groups with the different German Stenotaenia linearis clades. The strongly different Stenotaenia linearis lineages within Germany, independent of geography, are a strong hint for the presence of additional, cryptic Stenotaenia species in Germany.     

Biosynthesis of gangliosides in primary cultures of rat hepatocytes. Determination of the net synthesis of individual gangliosides by incorporation of labeled N-acetylmannosamine

The ganglioside content of rat hepatocytes increases several-fold during the first 6 days in monolayer culture. To correlate increased levels with rates of de novo synthesis, the incorporation of N-acetyl-[6-3H]D-mannosamine into individual gangliosides was determined. The calculation of synthetic rates was made possible by the simultaneous measurement of the specific radioactivity of the immediate sialic-acid donor, CMP-Neu5Ac. The CMP-Neu5Ac content of hepatocytes was found by HPLC analysis to be 30.5 nmol/g of plated cells. The specific radioactivity of this precursor pool reached a constant plateau 5 h after addition of the labeled N-acetyl-mannosamine and remained constant for at least 70 h. The incorporation into individual gangliosides was measured in primary cultures of rat hepatocytes between 72 and 144 h after seeding. During this period, the increase in ganglioside levels was greatest. The highest rates of incorporation were seen in GD1a followed by GM3, GM1, GD3 and the polysialylated compounds. The following rates of synthesis (nmol per 60 h and mg of protein) were calculated: GD1a 0.68, GM3 0.59, GM1 0.36, GD3 0.13 and GT1 0.02. These values are compared with the net increase of the gangliosides as measured by the resorcinol reaction.     

HDAC6 inhibition restores TDP‐43 pathology and axonal transport defects in human motor neurons with TARDBP mutations

TDP‐43 is the major component of pathological inclusions in most ALS patients and in up to 50% of patients with frontotemporal dementia (FTD). Heterozygous missense mutations in TARDBP, the gene encoding TDP‐43, are one of the common causes of familial ALS. In this study, we investigate TDP‐43 protein behavior in induced pluripotent stem cell (iPSC)‐derived motor neurons from three ALS patients with different TARDBP mutations, three healthy controls and an isogenic control. TARDPB mutations induce several TDP‐43 changes in spinal motor neurons, including cytoplasmic mislocalization and accumulation of insoluble TDP‐43, C‐terminal fragments, and phospho‐TDP‐43. By generating iPSC lines with allele‐specific tagging of TDP‐43, we find that mutant TDP‐43 initiates the observed disease phenotypes and has an altered interactome as indicated by mass spectrometry. Our findings also indicate that TDP‐43 proteinopathy results in a defect in mitochondrial transport. Lastly, we show that pharmacological inhibition of histone deacetylase 6 (HDAC6) restores the observed TDP‐43 pathologies and the axonal mitochondrial motility, suggesting that HDAC6 inhibition may be an interesting therapeutic target for neurodegenerative disorders linked to TDP‐43 pathology.