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Impact of temperature on Phenolic and Osmolyte contents in In Vitro cultures and micropropagated plants of two mediterranean plant species, Lavandula viridis and Thymus lotocephalus

Publication . Mansinhos, Inês; Gonçalves, Sandra; Rodríguez Solana, Raquel; Ordóñez-Díaz, José Luis; Moreno-Rojas, José Manuel; Romano, Anabela

In this study, in vitro cultures and micropropagated plants of two Mediterranean aromatic plants, Lavandula viridis L’Hér and Thymus lotocephalus López and Morales, were exposed to different temperatures (15, 20, 25, and 30 ◦C). The effect of temperature on the levels of hydrogen peroxide (H2O2 ), lipid peroxidation, and osmoprotectants (proline, soluble sugars, and soluble proteins), as well as on the phenolic profile by HPLC-HRMS and intermediates of the secondary metabolism (phenylalanine ammonia lyase (PAL) activity and shikimic acid content), was investigated. Moreover, the antioxidant activity of the plant extracts was also analyzed. Overall, considering the lipid peroxidation and H2O2 content, the extreme temperatures (15 and 30 ◦C) caused the greatest damage to both species, but the osmoprotectant response was different depending on the species and plant material. In both species, phenolic compounds and related antioxidant activity increased with the rise in temperature in the micropropagated plants, while the opposite occurred in in vitro cultures. L. viridis cultures showed the highest biosynthesis of rosmarinic acid (92.6 g/kgDW) at 15 ◦C and seem to be a good alternative to produce this valuable compound. We conclude that contrasting temperatures greatly influence both species’ primary and secondary metabolism, but the response is different depending on the plant micropropagation stage.

2022-12-14Journal article

Open Access

Revising the oldest oldowan: updated optimal linear estimation models and the impact of Nyayanga (Kenya)

Publication . Key, Alastair; Proffitt, Tomos

The Oldowan lithic industry represents the earliest known evidence of efficiently and expeditiously produced flake stone tools (Toth, 1985; Braun et al., 2019; Reti, 2016; Stout et al., 2019). Complex technological strategies were employed to produce these artefacts compared to earlier hominin stone tools, and potential organic tool-use behaviors inferred via parsimony with non-human primates (Braun et al., 2019; Boesch et al., 2020; Delagnes and Roche, 2005; Gürbüz and Lycett, 2021; Harmand et al., 2015; Lombard et al., 2018; Plummer et al., 2023; Proffitt et al., 2023a, 2023b; Stout et al., 2010; Toth and Schick, 2009). Consequently, the emergence of the Oldowan can still (cf. Leakey, 1971) be argued to reflect a behavioral and evolutionary shift within the hominin lineage, although the nature and species-associations of any changes have become less clear in recent years (Bobe and Wood, 2021; Braun et al., 2019; Hovers, 2012; Lewis and Harmand, 2016; Plummer et al., 2023). Nyayanga, located in the Homa Peninsula of Kenya, has recently emerged as an important archaeological and paleontological site yielding evidence of Oldowan stone tools and butchered fauna dating to between 2.595 and 3.032 Ma (Plummer et al., 2023). These findings not only represent the earliest currently known occurrences of the Oldowan but also greatly expand our understanding of its early geographic distribution. Further, some lithics at Nyayanga were found alongside Paranthropus molars, challenging prevailing assumptions regarding Oldowan species-associations and providing a rare instance of Early Stone Age (ESA) hominin fossil and lithic remains in close association. The co-occurrence of cut marked fauna and flakes, including those excavated in direct contact with hippopotamid remains, further distin guishes Nyayanga as an exceptional ESA occurrence extending hominin dietary and technological behaviors “similar to other Oldowan assem blages” into the Pliocene (Plummer et al., 2023: 563).

2024Journal article

Open Access