A genome-wide Drosophila screen for heat nociception identifies α2δ3 as an evolutionarily conserved pain gene

Worldwide, acute, and chronic pain affects 20% of the adult population and represents an enormous financial and emotional burden. Using genome-wide neuronal-specific RNAi knockdown in Drosophila, we report a global screen for an innate behavior and identify hundreds of genes implicated in heat nociception, including the α2δ family calcium channel subunit straightjacket (stj). Mice mutant for the stj ortholog CACNA2D3 (α2δ3) also exhibit impaired behavioral heat pain sensitivity. In addition, in humans, α2δ3 SNP variants associate with reduced sensitivity to acute noxious heat and chronic back pain. Functional imaging in α2δ3 mutant mice revealed impaired transmission of thermal pain-evoked signals from the thalamus to higher-order pain centers. Intriguingly, in α2δ3 mutant mice, thermal pain and tactile stimulation triggered strong cross-activation, or synesthesia, of brain regions involved in vision, olfaction, and hearing.     

A new modified ortho cleavage pathway of 3-chlorocatechol degradation by Rhodococcus opacus 1CP: genetic and biochemical evidence

The 4-chloro- and 2,4-dichlorophenol-degrading strain Rhodococcus opacus 1CP has previously been shown to acquire, during prolonged adaptation, the ability to mineralize 2-chlorophenol. In addition, homogeneous chlorocatechol 1,2-dioxygenase from 2-chlorophenol-grown biomass has shown relatively high activity towards 3-chlorocatechol. Based on sequences of the N terminus and tryptic peptides of this enzyme, degenerate PCR primers were now designed and used for cloning of the respective gene from genomic DNA of strain 1CP. A 9.5-kb fragment containing nine open reading frames was obtained on pROP1. Besides other genes, a gene cluster consisting of four chlorocatechol catabolic genes was identified. As judged by sequence similarity and correspondence of predicted N termini with those of purified enzymes, the open reading frames correspond to genes for a second chlorocatechol 1,2-dioxygenase (ClcA2), a second chloromuconate cycloisomerase (ClcB2), a second dienelactone hydrolase (ClcD2), and a muconolactone isomerase-related enzyme (ClcF). All enzymes of this new cluster are only distantly related to the known chlorocatechol enzymes and appear to represent new evolutionary lines of these activities. UV overlay spectra as well as high-pressure liquid chromatography analyses confirmed that 2-chloro-cis,cis-muconate is transformed by ClcB2 to 5-chloromuconolactone, which during turnover by ClcF gives cis-dienelactone as the sole product. cis-Dienelactone was further hydrolyzed by ClcD2 to maleylacetate. ClcF, despite its sequence similarity to muconolactone isomerases, no longer showed muconolactone-isomerizing activity and thus represents an enzyme dedicated to its new function as a 5-chloromuconolactone dehalogenase. Thus, during 3-chlorocatechol degradation by R. opacus 1CP, dechlorination is catalyzed by a muconolactone isomerase-related enzyme rather than by a specialized chloromuconate cycloisomerase.     

Beneficial Effect of Antibodies against β- Secretase Cleavage Site of App on Alzheimer’s-Like Pathology in Triple-Transgenic Mice

The toxicity of amyloid β and tau, the two hallmark proteins in Alzheimer’s disease (AD), has been extensively studied individually. Recently new data suggest their possible interactions and synergistic effects in the disease. In this study, we investigate the ability of antibodies against the β secretase cleavage site on APP, named BBS1, to affect tau pathology, besides their well established effect on intracellular Aβ and amyloid load. For this purpose we treated the triple transgenic mice model of AD (3x Tg-AD) with mAb BBS1 intracerebroventricularly, using mini osmotic pumps for one month. The experimental data demonstrated reduction in total and phosphorylated tau levels, explained by significant reduction in GSK3β which phosphorylates tau on sites recognized by antibodies against PHF1 and AT-8. The treatment increased the cognitive capabilities and reduced the brain inflammation levels which accompany AD pathology. The data showing that tau pathology was significantly reduced by BBS1 antibodies suggest a close interaction between tau and Aβ in the development of AD, and may serve as an efficient novel immunotherapy against both hallmarks of this disease.     

The alanine-serine-cysteine-1 (Asc-1) transporter controls glycine levels in the brain and is required for glycinergic inhibitory transmission

Asc-1 (SLC7A10) is an amino acid transporter whose deletion causes neurological abnormalities and early postnatal death in mice. Using metabolomics and behavioral and electrophysiological methods, we demonstrate that Asc-1 knockout mice display a marked decrease in glycine levels in the brain and spinal cord along with impairment of glycinergic inhibitory transmission, and a hyperekplexia-like phenotype that is rescued by replenishing brain glycine. Asc-1 works as a glycine and L-serine transporter, and its transport activity is required for the subsequent conversion of L-serine into glycine in vivo. Asc-1 is a novel regulator of glycine metabolism and a candidate for hyperekplexia disorders.     

Rose scent: genomics approach to discovering novel floral fragrance-related genes

For centuries, rose has been the most important crop in the floriculture industry; its economic importance also lies in the use of its petals as a source of natural fragrances. Here, we used genomics approaches to identify novel scent-related genes, using rose flowers from tetraploid scented and nonscented cultivars. An annotated petal EST database of approximately 2100 unique genes from both cultivars was created, and DNA chips were prepared and used for expression analyses of selected clones. Detailed chemical analysis of volatile composition in the two cultivars, together with the identification of secondary metabolism-related genes whose expression coincides with scent production, led to the discovery of several novel flower scent-related candidate genes. The function of some of these genes, including a germacrene D synthase, was biochemically determined using an Escherichia coli expression system. This work demonstrates the advantages of using the high-throughput approaches of genomics to detail traits of interest expressed in a cultivar-specific manner in nonmodel plants. EST sequences were submitted to the GenBank database (accession numbers BQ 103855 to BQ 106728).     

Growth and sporulation of the arbuscular mycorrhizal fungus Glomus caledonium in dual culture with transformed carrot roots

Glomus caledonium was established in a dual culture with Ri T-DNA-transformed carrot roots. A modification of the minimal M medium buffered at pH 6.50 with 10 mM MES and solidified with 0.4% unpurified gellan gum allowed spore germination and formation of the symbiosis, together with the development of an extensive extramatrical mycelium and sporulation. Spore production increased with culture generation and most spores were viable. These spores colonized carrot roots and completed the fungal life cycle. In many cultures, sporulation was accompanied by the formation of arbuscule-like structures on short and thickened lateral branches of main hyphae. Root colonization was of the Paris-type with hyphae spreading intracellularly. Most colonized root cells contained coils of thickened hyphae, sometimes surrounded by fine hyphae, but no typical arbuscules were observed. Accepted: 26 January 2000     

Functional interrogation of a SARS-CoV-2 host protein interactome identifies unique and shared coronavirus host factors

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Temperature but not ocean acidification affects energy metabolism and enzyme activities in the blue mussel,Mytilus edulis

1. In mosaic marine habitats, such as intertidal zones, ocean acidification (OA) is exacerbated by high variability of pH, temperature, and biological CO₂ production. The nonlinear interactions among these drivers can be context‐specific and their effect on organisms in these habitats remains largely unknown, warranting further investigation.
2. We were particularly interested in Mytilus edulis (the blue mussel) from intertidal zones of the Gulf of Maine (GOM), USA, for this study. GOM is a hot spot of global climate change (average sea surface temperature (SST) increasing by >0.2°C/year) with >60% decline in mussel population over the past 40 years.
3. Here, we utilize bioenergetic underpinnings to identify limits of stress tolerance in M. edulis from GOM exposed to warming and OA. We have measured whole‐organism oxygen consumption rates and metabolic biomarkers in mussels exposed to control and elevated temperatures (10 vs. 15°C, respectively) and current and moderately elevated P _CO2 levels (~400 vs. 800 µatm, respectively).
4. Our study demonstrates that adult M. edulis from GOM are metabolically resilient to the moderate OA scenario but responsive to warming as seen in changes in metabolic rate, energy reserves (total lipids), metabolite profiles (glucose and osmolyte dimethyl amine), and enzyme activities (carbonic anhydrase and calcium ATPase).
5. Our results are in agreement with recent literature that OA scenarios for the next 100–300 years do not affect this species, possibly as a consequence of maintaining its in vivo acid‐base balance.

     

Studying the genotoxic effects of high intensity terahertz radiation on fibroblasts and CNS tumor cells

The data is obtained on the effect of high-intensity pulses of terahertz (THz) radiation with a broad spectrum (0.2–3 THz) on cell cultures. We have evaluated the threshold exposure parameters of THz radiation causing genotoxic effects in fibroblasts. Phosphorylation of histone H2AX at Ser 139 (γH2AX) was chosen as a marker for genotoxicity and a quantitative estimation of γH2AX foci number in fibroblasts was performed after cell irradiation with THz pulses for 30 min. No genotoxic effects of THz radiation were observed in fibroblasts unless peak intensity and electric field strength exceeded 21 GW cm⁻² and 2.8 MV cm⁻¹, respectively. In tumor cell lines (neuroblastoma (SK-N-BE (2)) and glioblastoma (U87)), exposure to THz pulses with peak intensity of 21 GW cm⁻² for 30 min caused no morphological changes as well as no statistically significant increase in histone phosphorylation foci number.