Brain central regions in courtship sound production in Drosophila melanogaster

There are debates about the function of the two main central brain structures of insects--mushroom bodies and the central complex--in the control of motor co-ordination and triggering of different behaviour programs including sound production. To throw additional light onto this problem we analysed the parameters of the love song produced by 5-day old males courting for 5 minutes a fertilised CS female at 25 degrees C, in two wild-type strains of Drosophila melanogaster (Berlin and CS), hydroxyurea (HU)-treated flies (chemical ablation of the mushroom bodies) two mushroom body mutants (mbm1 and mud1), two central complex mutants (ccbKS127 and cexKS181) and a mutant cxbN71 with defects both in the mushroom bodies and in the central complex. It was found that the love song of HU-treated flies devoid of the mushroom bodies is very similar to that of wild-type flies. In mbm1 and mud1 the main parameters of the song (interpulse interval, IPI, and train duration) are slightly shifted from those of wild type but the sharpness of tuning of the pulse oscillator is the same. The flies of all these strains are equal to wild-type strains in mating success (% of copulations with virgins in 10-min test). On the contrary, the songs of the central complex mutants differ from those of wild-type flies. First of all, the sharpness of tuning of the pulse oscillator is destroyed,--the IPIs become highly variable. The pulses often are much longer and polycyclic as in well known cacophony mutant. The mean duration of pulse trains is much shorter. The males of the mutant cexKS181 usually court violently, but in most cases abnormal sounds are produced. Both cexKS181 and ccbKS127 males are much less successful in matings in comparison to wild-type flies. One can conclude that the central complex plays probably a very important role in the control of singing, whereas the mushroom bodies are practically not involved in this function.     

Experimental and computational analysis of the ancestry of an evolutionary young enzyme from histidine biosynthesis

The conservation of fold and chemistry of the enzymes associated with histidine biosynthesis suggests that this pathway evolved prior to the diversification of Bacteria, Archaea, and Eukaryotes. The only exception is the histidinol phosphate phosphatase (HolPase). So far, non-homologous HolPases that possess distinct folds and belong to three different protein superfamilies have been identified in various phylogenetic clades. However, their evolution has remained unknown to date. Here, we analyzed the evolutionary history of the HolPase from γ-Proteobacteria (HisB-N). It has been argued that HisB-N and its closest homologue d -glycero-d -manno-heptose-1,7-bisphosphate 7-phosphatase (GmhB) have emerged from the same promiscuous ancestral phosphatase. GmhB variants catalyze the hydrolysis of the anomeric d -glycero-d -manno-heptose-1,7-bisphosphate (αHBP or βHBP) with a strong preference for one anomer (αGmhB or βGmhB). We found that HisB-N from Escherichia coli shows promiscuous activity for βHBP but not αHBP, while βGmhB from Crassaminicella sp. shows promiscuous activity for HolP. Accordingly, a combined phylogenetic tree of αGmhBs, βGmhBs, and HisB-N sequences revealed that HisB-Ns form a compact subcluster derived from βGmhBs. Ancestral sequence reconstruction and in vitro analysis revealed a promiscuous HolPase activity in the resurrected enzymes prior to functional divergence of the successors. The following increase in catalytic efficiency of the HolP turnover is reflected in the shape and electrostatics of the active site predicted by AlphaFold. An analysis of the phylogenetic tree led to a revised evolutionary model that proposes the horizontal gene transfer of a promiscuous βGmhB from δ- to γ-Proteobacteria where it evolved to the modern HisB-N.     

Diethyldithiocarbamate Potentiates the Neurotoxicity of In Vivo l-Methyl-4-Phenyl-1, 2, 3, 6-Tetrahydropyridine and of In Vitro 1-Methyl-4-Phenylpyridinium

Diethyldithiocarbamic acid (DDC) potentiates in vivo neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and in vitro neurotoxicity of 1-methyl-4-phenylpyridinium (MPP+). Male C57B1/6 mice were given two or five injections of MPTP (30 mg/kg i.p.) preceded 0.5 h by DDC (400 mg/kg i.p.). The mice were tested for catalepsy, akinesia, or motor activity during and after the period of dosing. Striatal and hippocampal tissues were obtained at 2 and 7 days following the last injection and evaluated for dopamine and norepinephrine levels, respectively. These same tissues were also analyzed for the levels of glial fibrillary acidic protein (GFAP), an astrocyte-localized protein known to increase in response to neural injury. Pretreatment with DDC potentiated the effect of MPTP in striatum and resulted in substantially greater dopamine depletion, as well as a more pronounced elevation in GFAP. In hippocampus, the levels of norepinephrine and GFAP were not different from controls in mice receiving only MPTP, but pretreatment with DDC resulted in a sustained depletion of norepinephrine and an elevation of GFAP, suggesting that damage was extended to this brain area by the combined treatment. Mice receiving MPTP preceded by DDC also demonstrated a more profound, but reversible, catalepsy and akinesia compared to those receiving MPTP alone. Systemically administered MPP+ decreased heart norepinephrine, but did not alter the striatal levels of dopamine or GFAP, and pretreatment with DDC did not alter these effects, but did increase lethality. DDC is known to increase brain levels of MPP+ after MPTP, but our data indicate that this is not due to a movement of peripherally generated MPP+ into CNS.(ABSTRACT TRUNCATED AT 250 WORDS)     

CYLD negatively regulates cell‐cycle progression by inactivating HDAC6 and increasing the levels of acetylated tubulin

CYLD is a tumour‐suppressor gene that is mutated in a benign skin tumour syndrome called cylindromatosis. The CYLD gene product is a deubiquitinating enzyme that was shown to regulate cell proliferation, cell survival and inflammatory responses, mainly through inhibiting NF‐κB signalling. Here we show that CYLD controls cell growth and division at the G₁/S‐phase as well as cytokinesis by associating with α‐tubulin and microtubules through its CAP‐Gly domains. Translocation of activated CYLD to the perinuclear region of the cell is achieved by an inhibitory interaction of CYLD with histone deacetylase‐6 (HDAC6) leading to an increase in the levels of acetylated α‐tubulin around the nucleus. This facilitates the interaction of CYLD with Bcl‐3, leading to a significant delay in the G₁‐to‐S‐phase transition. Finally, CYLD also interacts with HDAC6 in the midbody where it regulates the rate of cytokinesis in a deubiquitinase‐independent manner. Altogether these results identify a mechanism by which CYLD regulates cell proliferation at distinct cell‐cycle phases.     

SNARE assembly and disassembly exhibit a pronounced hysteresis.

SNARE proteins are essential for intracellular membrane fusion of eukaryotes. Their assembly into stable four-helix bundles bridges membranes and may provide the energy for initiating membrane fusion. In vitro, assembly of soluble SNARE fragments is accompanied by major structural rearrangements that can be described as a folding reaction. The pathways and the thermodynamics of SNARE protein interactions, however, are not known. Here we report that assembly and dissociation of two distantly related SNARE complexes exhibit a marked hysteresis. The assembled and disassembled native states are separated by a kinetic barrier and cannot equilibrate on biologically relevant timescales. We suggest that the hysteresis is a hallmark of all SNARE complexes and that complex assembly and disassembly follow different pathways that may be independently controlled.     

Enamel Matrix Derivative Inhibits Adipocyte Differentiation of 3T3-L1 Cells via Activation of TGF-βRI Kinase Activity

Enamel matrix derivative (EMD), an extract of fetal porcine enamel, and TGF-β can both suppress adipogenic differentiation. However, there have been no studies that functionally link the role of EMD and TGF-β in vitro. Herein, we examined whether TGF-β signaling contributes to EMD-induced suppression of adipogenic differentiation. Adipogenesis was studied with 3T3-L1 preadipocytes in the presence of SB431542, an inhibitor of TGF-βRI kinase activity. SB431542 reversed the inhibitory effect of EMD on adipogenic differentiation, based on Oil Red O staining and mRNA expression of lipid regulated genes. SB431542 also reduced EMD-stimulated expression of connective tissue growth factor (CTGF), an autocrine inhibitor of adipogenic differentiation. Moreover, short interfering (si)RNAs for CTGF partially reversed the EMD-induced suppression of lipid regulated genes. We conclude that the TGF-βRI - CTGF axis is involved in the anti-adipogenic effects of EMD in vitro.     

Root system development of Lotus corniculatus L. in calcareous sands with embedded finer-textured fragments in an initial soil

Background and aims

In post mining landscapes as in the Lusatian region (Brandenburg, Germany), Pleistocene coarse-textured, sandy sediments are used for soil rehabilitation and land reclamation. The homogeneously-appearing initial soils are characterized by finer-textured soil clumps (fragments) of different sizes that are embedded in a sandy matrix. These soils with typical local-scale heterogeneity may serve as a model for studying how spatially-distributed soil fragments may be utilized by pioneering plant species. The aim of this study was to gain insight into the physical and chemical properties of sandy matrix and fragments that could possibly explain why embedded fragment may act as hot spots for root growth.

Methods

In 2009, three soil monoliths of dimension 50 cm?×?50 cm?×?50 cm that were exclusively vegetated by Lotus corniculatus L. planted in 2008 were studied. Each layer of 10 cm was sampled successively using a cubic metal frame with 10 cm edge length (25 samples per layer each with a volume of 1 l). The samples were analyzed for root biomass, root lengths and diameter, and for chemical and physical properties of sandy matrix and fragments.

Results

Bulk density, water contents, total carbon, total nitrogen, and plant available calcium contents were higher for the fragments compared to the sandy matrix. The roots of L. corniculatus were heterogeneously distributed in the monoliths. The root density distributions for the 1 L samples indicated a positive influence of fragments on directed root growth. Fragments embedded in the sandy matrix were found to be strongly penetrated by roots despite their relatively high bulk density. The presence of fragments also led to an increased root biomass in the sandy matrix in the direct vicinity of fragments. Such direct effects on root development were accompanied by more indirect effects by locally-elevated moisture and nutrient contents.

Conclusion

The results suggest that finer-textured fragments embedded in coarser-textured sediments, can have favorable effect on plant and root development during the initial stages of establishment of vegetation cover. The fragments can act as water and nutrient hot spots to improve supply of pioneering plants especially in coarse-textured soil. The existence of small-scale heterogeneities owing to incomplete sediment mixing e.g., in soil reclamation, could be generally important for controlling the speed and direction of early plants-establishment, for instance, in the succession of post-mining areas.     

Survival of thermophilic and hyperthermophilic microorganisms after exposure to UV-C,ionizing radiation and desiccation

In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylogenetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyperthermophilic microorganisms.     

Discovery of benzo[g]indol-3-carboxylates as potent inhibitors of microsomal prostaglandin E2 synthase-1

Selective inhibition of pro-inflammatory prostaglandin (PG)E₂ formation via microsomal PGE₂ synthase-1 (mPGES-1) might be superior over inhibition of all cyclooxygenase (COX)-derived products by non-steroidal anti-inflammatory drugs (NSAIDs) and coxibs. We recently showed that benzo[g]indol-3-carboxylates potently suppress leukotriene biosynthesis by inhibiting 5-lipoxygenase. Here, we describe the discovery of benzo[g]indol-3-carboxylates as a novel class of potent mPGES-1 inhibitors (IC₅₀ ? 0.1 μM). Ethyl 2-(3-chlorobenzyl)-5-hydroxy-1H-benzo[g]indole-3-carboxylate (compound 7a) inhibits human mPGES-1 in a cell-free assay (IC₅₀ = 0.6 μM) as well as in intact A549 cells (IC₅₀ = 2 μM), and suppressed PGE₂ pleural levels in rat carrageenan-induced pleurisy. Inhibition of cellular COX-1/2 activity was significantly less pronounced. Compound 7a significantly reduced inflammatory reactions in the carrageenan-induced mouse paw edema and rat pleurisy. Together, based on the select and potent inhibition of mPGES-1 and 5-lipoxygenase, benzo[g]indol-3-carboxylates possess potential as novel anti-inflammatory drugs with a valuable pharmacological profile.