Mid-Cretaceous Burmese amber pelecinid wasps (Hymenoptera,Pelecinidae) support the hypothesis of an Asian origin of the family

A new species of pelecinid wasp, Eopelecinus marechali sp. nov., is described and figured from mid-Cretaceous Burmese amber based on a single well-preserved female specimen. Contrary to Eopelecinus inopinatus Jouault et al., 2020a, unique other Eopelecinus known from this deposit, the new species is based on a complete female specimen. This discovery confirms that the Pelecinidae were highly diverse during the Cretaceous and highlights the underestimated diversity of the genus Eopelecinus in Burmese amber biota. Eopelecinus marechali sp. nov. differs from all other Eopelecinus species by its unique metasomal ratio. A summary on the fossil pelecinid species with distributions and ages is provided. Based on the particular geological history of the West Burmese Terrane and the fossil record of the family, the hypothesis of an Asian origin of the family is discussed. The records of Eopelecinus in both Laurasia and Burmese amber biota, during the mid-Cretaceous, suggest that possible transfers of fauna have taken place between these two geological blocks.     

A multiplex PCR-based method for the detection and early identification of wood rotting fungi in standing trees

AIMS: The goal of this research was the development of a PCR-based assay to identify important decay fungi from wood of hardwood tree species in northern temperate regions. METHODS AND RESULTS: Eleven taxon-specific primers were designed for PCR amplification of either nuclear or mitochondrial ribosomal DNA regions of Armillaria spp., Ganoderma spp., Hericium spp., Hypoxylon thouarsianum var. thouarsianum, Inonotus/Phellinus-group, Laetiporus spp., Perenniporia fraxinea, Pleurotus spp., Schizophyllum spp., Stereum spp. and Trametes spp. Multiplex PCR reactions were developed and optimized to detect fungal DNA and identify each taxon with a sensitivity of at least 1 pg of target DNA in the template. This assay correctly identified the agents of decay in 82% of tested wood samples. CONCLUSIONS: The development and optimization of multiplex PCRs allowed for reliable identification of wood rotting fungi directly from wood. SIGNIFICANCE AND IMPACT OF THE STUDY: Early detection of wood decay fungi is crucial for assessment of tree stability in urban landscapes. Furthermore, this method may prove useful for prediction of the severity and the evolution of decay in standing trees.     

Functional diversification in the Nudix hydrolase gene family drives sesquiterpene biosynthesis in Rosa × wichurana

Roses use a non‐canonical pathway involving a Nudix hydrolase, RhNUDX1, to synthesize their monoterpenes, especially geraniol. Here we report the characterization of another expressed NUDX1 gene from the rose cultivar Rosa x wichurana, RwNUDX1‐2. In order to study the function of the RwNUDX1‐2 protein, we analyzed the volatile profiles of an F₁ progeny generated by crossing R. chinensis cv. ‘Old Blush’ with R. x wichurana. A correlation test of the volatilomes with gene expression data revealed that RwNUDX1‐2 is involved in the biosynthesis of a group of sesquiterpenoids, especially E,E‐farnesol, in addition to other sesquiterpenes. In vitro enzyme assays and heterologous in planta functional characterization of the RwNUDX1‐2 gene corroborated this result. A quantitative trait locus (QTL) analysis was performed using the data of E,E‐farnesol contents in the progeny and a genetic map was constructed based on gene markers. The RwNUDX1‐2 gene co‐localized with the QTL for E,E‐farnesol content, thereby confirming its function in sesquiterpenoid biosynthesis in R. x wichurana. Finally, in order to understand the structural bases for the substrate specificity of rose NUDX proteins, the RhNUDX1 protein was crystallized, and its structure was refined to 1.7 Å. By molecular modeling of different rose NUDX1 protein complexes with their respective substrates, a structural basis for substrate discrimination by rose NUDX1 proteins is proposed.     

Impairment of GABAB receptor dimer by endogenous 14-3-3ζ in chronic pain conditions

In the central nervous system, the inhibitory GABAB receptor is the archetype of heterodimeric G protein-coupled receptors (GPCRs). However, the regulation of GABAB dimerization, and more generally of GPCR oligomerization, remains largely unknown. We propose a novel mechanism for inhibition of GPCR activity through de-dimerization in pathological conditions. We show here that 14-3-3ζ, a GABAB1-binding protein, dissociates the GABAB heterodimer, resulting in the impairment of GABAB signalling in spinal neurons. In the dorsal spinal cord of neuropathic rats, 14-3-3ζ is overexpressed and weakens GABAB inhibition. Using anti-14-3-3ζ siRNA or competing peptides disrupts 14-3-3ζ/GABAB1 interaction and restores functional GABAB heterodimers in the dorsal horn. Importantly, both strategies greatly enhance the anti-nociceptive effect of intrathecal Baclofen in neuropathic rats. Taken together, our data provide the first example of endogenous regulation of a GPCR oligomeric state and demonstrate its functional impact on the pathophysiological process of neuropathic pain sensitization.     

A shift in nuclear state as the result of natural interspecific hybridization between two North American taxa of the basidiomycete complex Heterobasidion

A natural first generation hybrid fungus shows interspecific heterozygosity. The nuclear condition of a rare natural hybrid between two taxa of the Heterobasidion complex is investigated. Heterobasidion species are known to be either homokaryotic (haploid) or heterokaryotic (n+n), but heterokaryons are made up of both homokaryotic and heterokaryotic sectors. The natural hybrid appears to be either a heterokaryon undergoing a primary homothallic phase or a diploid with limited ability to exchange nuclei when mated with homokaryons. The natural hybrid is stable and long lived, suggesting hybridization may play an important role in the evolutionary history of this fungal complex.     

Eukaryotic Initiation Factor 2B (eIF2B) GEF Activity as a Diagnostic Tool for EIF2B-Related Disorders

Background

In recent years, the phenotypes of leukodystrophies linked to mutations in the eukaryotic initiation factor 2B genes have been extended, classically called CACH/VWM (Childhood ataxia with cntral hypomyélination/vanishing white matter disorder). The large clinical spectrum observed from the more severe antenatal forms responsible for fetal death to milder adult forms with an onset after 16 years old and restricted to slow cognitive impairment have lead to the concept of eIF2B-related disorders. The typical MRI pattern with a diffuse CSF-like aspect of the cerebral white matter can lack particularly in the adult forms whereas an increasing number of patients with clinical and MRI criteria for CACH/VWM disease but without eIF2B mutations are found. Then we propose the use of biochemical markers to help in this difficult diagnosis. The biochemical diagnosis of eIF2B-related disorder is difficult as no marker, except the recently described asialotransferrin/transferrin ratio measured in cerebrospinal fluid, has been proposed and validated until now. Decreased eIF2B GEF activity has been previously reported in lymphoblastoid cell lines from 30 eIF2B-mutated patients. Our objective was to evaluate further the utility of this marker and to validate eIF2B GEF activity in a larger cohort as a specific diagnostic test for eIF2B-related disorders.

Methodology/Principal Findings

We performed eIF2B GEF activity assays in cells from 63 patients presenting with different clinical forms and eIF2B mutations in comparison to controls but also to patients with defined leukodystrophies or CACH/VWM-like diseases without eIF2B mutations. We found a significant decrease of GEF activity in cells from eIF2B-mutated patients with 100% specificity and 89% sensitivity when the activity threshold was set at ≤77.5%.

Conclusion

These results validate the measurement of eIF2B GEF activity in patients'' transformed-lymphocytes as an important tool for the diagnosis of eIF2B-related disorders.     

Novel liquid chromatography-electrospray ionization mass spectrometry method for the quantification in human urine of microbial aromatic acid metabolites derived from dietary polyphenols

An HPLC-ESI-MS-MS method was developed to quantify in human urine fourteen aromatic acids known as metabolites of dietary polyphenols. These metabolites were determined simultaneously in a single 20-min chromatographic analysis with multiple reaction monitoring detection. The inter- and intra-day precisions, calculated from quality control samples were 8.8 and 5.3%, respectively, and the mean accuracy was 2.3%. The method was tested on urine samples collected from one healthy volunteer who consumed a polyphenol-rich diet for 3 days. Increased levels of several aromatic acid metabolites were observed, demonstrating that the method can be used to detect changes in the excretion of microbial metabolites induced by the consumption of polyphenol-containing foods in humans.     

On the benzodiazepine binding pocket in GABAA receptors

Benzodiazepines are used for their sedative/hypnotic, anxiolytic, muscle relaxant, and anticonvulsive effects. They exert their actions through a specific high affinity binding site on the major inhibitory neurotransmitter receptor, the gamma-aminobutyric acid, type A (GABA(A)) receptor channel, where they act as positive allosteric modulators. To start to elucidate the relative positioning of benzodiazepine binding site ligands in their binding pocket, GABA(A) receptor residues thought to reside in the site were individually mutated to cysteine and combined with benzodiazepine analogs carrying substituents reactive to cysteine. Direct apposition of such reactive partners is expected to lead to an irreversible site-directed reaction. We describe here the covalent interaction of alpha(1)H101C with a reactive group attached to the C-7 position of diazepam. This interaction was studied at the level of radioactive ligand binding and at the functional level using electrophysiological methods. Covalent reaction occurs concomitantly with occupancy of the binding pocket. It stabilizes the receptor in its allosterically stimulated conformation. Covalent modification is not observed in wild type receptors or when using mutated alpha(1)H101C-containing receptors in combination with the reactive ligand pre-reacted with a sulfhydryl group, and the modification rate is reduced by the binding site ligand Ro15-1788. We present in addition evidence that gamma(2)Ala-79 is probably located in the access pathway of the ligand to its binding pocket.