A conscious rethink : Why is brain tissue commonly preserved in the archaeological record? Commentary on: Petrone P, Pucci P, Niola M, et al. Heat-induced brain vitrification from the Vesuvius eruption in C.E. 79. N Engl J Med 2020;382:383-4. DOI: 10.1056/NEJMc1909867

Brain tissue is ubiquitous in the archaeological record. Multiple, independent studies report the finding of black, resinous or shiny brain tissue, and Petrone et al. [2020 “Heat-induced Brain Vitrification from the Vesuvius Eruption in C.E. 79.” N Engl J Med. 382: 383–384; doi:10.1056/NEJMc1909867] raise the intriguing prospect of a role for vitrification in the preservation of ancient biomolecules. However, Petrone et al. (2020) have not made their raw data available, and no detailed laboratory or analytical methodology is offered. Issues of contamination and misinterpretation hampered a decade of research in biomolecular archaeology, such that addressing these sources of bias and facilitating validation of specious findings has become both routine and of paramount importance in the discipline. We argue that the evidence they present does not support their conclusion of heat-induced vitrification of human brain tissue, and that future studies should share palaeoproteomic data in an open access repository to facilitate comparative analysis of the recovery of ancient proteins and patterns of their degradation

Systems-wide analysis of manganese deficiency-induced changes in gene activity of Arabidopsis roots

Manganese (Mn) is pivotal for plant growth and development, but little information is available regarding the strategies that evolved to improve Mn acquisition and cellular homeostasis of Mn. Using an integrated RNA-based transcriptomic and high-throughput shotgun proteomics approach, we generated a comprehensive inventory of transcripts and proteins that showed altered abundance in response to Mn deficiency in roots of the model plant Arabidopsis. A suite of 22,385 transcripts was consistently detected in three RNA-seq runs; LC-MS/MS-based iTRAQ proteomics allowed the unambiguous determination of 11,606 proteins. While high concordance between mRNA and protein expression (R = 0.87) was observed for transcript/protein pairs in which both gene products accumulated differentially upon Mn deficiency, only approximately 10% of the total alterations in the abundance of proteins could be attributed to transcription, indicating a large impact of protein-level regulation. Differentially expressed genes spanned a wide range of biological functions, including the maturation, translation, and transport of mRNAs, as well as primary and secondary metabolic processes. Metabolic analysis by UPLC-qTOF-MS revealed that the steady-state levels of several major glucosinolates were significantly altered upon Mn deficiency in both roots and leaves, possibly as a compensation for increased pathogen susceptibility under conditions of Mn deficiency

Cloning of two contrasting high-affinity sulfate transporters from tomato induced by low sulfate and infection by the vascular pathogen Verticillium dahliae

Two cDNAs, LeST1-1 (AF347613) and LeST1-2 (AF347614), encoding sulfate transporters have been cloned from tomato (Lycopersicon esculentum Mill.) by reverse transcription-polymerase chain reaction and their expression characterised. Sharing 76% identity at the amino acid level, the transporters are phylogenetically associated with the Group-1, high-affinity plant sulfate transporters. Both were shown to have high affinity for sulfate by uptake kinetic analysis using a yeast (Saccharomyces cerevisiae) sulfate-transporter mutant. K values of 11.5 μM and 9.8 μM were calculated for LeST1-1 and LeST1-2, respectively, the same order of magnitude as those previously reported for several other Group-1 high-affinity sulfate transporters. In situ hybridisation to S-deficient tomato roots showed LeST1-1 to be expressed in the epidermis and pericycle, whereas LeST1-2 expression was located to the epidermis only. Northern analysis shows that the mRNA abundances of both LeST1-1 and LeST1-2 are upregulated in the root in response to sulfate deprivation. LeST1-1 is specifically expressed in root tissue, a characteristic of Group-1 sulfate transporters. LeST1-2, however, was also detected in tomato leaves and stems and is upregulated and expressed to a similar extent in these tissues under conditions of sulfate deprivation. Induction of LeST1-2 expression was also observed in the vascular tissues of a resistant line of tomato infected with the vascular wilt pathogen Verticillium dahliae

Calmodulin antagonists inhibit the phytochrome‐induced appearance of two nuclear encoded transcripts in radish cotyledons

International audienceThe effects of two calmodulin antagonists on the phytochrome‐mediated appearance of two nuclear encoded transcripts in radish cotyledons have been investigated. The extent of inhibition of transcript accumulation was dependent of the time ellapsed between the administration of trifluoperazine and the light stimulus. When 1 mM trifluoperazine was administered to the seedlings 8 h before red light irradiation, the inhibition of transcript accumulation was up to 62% for the chlorophyll binding protein mRNA and 56% for the ribulose 1,5‐bisphosphate carboxylase small subunit mRNA. Similar results were obtained with W‐7 (0.1 mM)