The effects of methyl jasmonate (MeJ) on growth and taxoid formation in the cell culture of Himalayan yew was investigated for elucidate the specifics of the action of phytohormones on dedifferentiated plant cells in vitro. The characteristics of the same suspension culture of Taxus wallichiana was compared in 2017 ("young culture") and in 2022 ("old culture") - 1.5 or 6 years after culture induction, respectively. Cells were grown in flasks and bioreactors, MeJ (100 µM) was added at the exponential growth phase. It was found that cell culture demonstrated good growth (dry weight (DW) accumulation 10–18 g/l, specific growth rate µ = 0.15–0.35 day-1) regardless of "age", cultivation system and MeJ addition. UPLC–ESI-MS analysis showed the presence of C14-hydroxylated taxoids (yunnanxane, taxuyunnanine C, sinenxane C, sinenxane B) in cell biomass in the amounts comparable to plants. The content of C14-OH taxoids during 5 years of cultivation increased by 3-5 times. It was 0.2–1.6 mg/g DW for "young culture” and 0.6-10.1 mg/g for “old culture” depending on cultivation conditions. The ratio of individual compounds changed also: in the "young culture" was predominant yunnanxane, in the "old culture" - sinenxane C. Important that C13-hydroxylated taxoids were found in trace amounts only in the "young culture” (below 0.05 mg/g DW) and were not detected in the "old culture”. The response to MeJ was radically different depending on culture’s «age». In the “young culture”, exogenous MeJ had no effect on the content of C14-OH com-pounds, but significantly (almost 10 times) increased the content of C13-OH compounds. In particular, paclitaxel concentration was elevated up to 0.12–0.19 mg/g DW, which is comparable to its content in the bark of yew trees. By contrast, MeJ added to the "old culture” had minor effect on the synthesis of C13-OH toxoids that appeared in trace amounts only (below 3.5 µg/g DW for paclitaxel) but notably increased the content of C14-OH compounds (1.5–2.0 times in flasks and 5–8 times in bioreactors). These findings suggest that hormonal signaling in dedifferentiated yew cells grown in vitro is different from that in plants and change with culture age. This might be a result of the high level of heterogeneity of cells in vitro and their constant auto-selection for proliferate intensity which leads to predominant formation of C14-OH taxoids versus C13-OH taxoids and modified cell response to exogenous MeJ treatment. These results have both fundamental and practical biotechnological application.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopamin-ergic neurons responsible for unintended or uncontrollable movements. Mutations in leu-cine-rich repeat kinase 2 locus, contributes to genetic forms of PD. The fruit fly Drosophila mela-nogaster carrying this mutation (LRRK2-Dm), is an in vivo model of PD that develops motor impairment and stands for an eligible non mammalian paradigm to test novel therapeutic ap-proaches. Dehydrozingerone (DHZ) is a natural phenolic compound isolated from ginger. Pre-sents anti-inflammatory, antioxidant and neuroprotective properties making it a potential therapeutic target for PD. We administered DHZ and its C2-symmetric dimer (DHZ-DIM) at 0.5 and 1mM, for 14 and 21 days, in the LRRK2-Dm, with the aim to assess changes for rescuing motor behavior, brain dopaminergic neurons, mitochondria and synapses (T-Bars). The shorter treat-ment with both molecules revealed efficacy at the higher dose improving climbing behavior with a prevention of dopaminergic neuronal demise. After 21 days, a recovery of the motor disability, dopaminergic neuron loss, mitochondrial damage and T-Bars failure was observed with the DHZ-DIM. Our data indicates that the DHZ-DIM exerts a more potent neuroprotective effect respect to the monomer in LRRK2-Dm, prompting further investigation of these compounds in rodent models of PD.

PHA synthases (PhaC) are grouped into four classes based on the kinetics and mechanisms of reaction. The grouping of PhaC enzymes into four classes is dependent on substrate specificity, according to the preference in forming short chain length (scl) or medium chain length (mcl) polymers: class I, class III, and class IV produce scl-PHAs depending on propionate, butyrate, valerate and hexanoate precursors, while class II phaC synthesize mcl-PHAs based on the alkane (C6 to C14) precursors. PHA synthases of class I, in particular PhaC_Cs from Chromobacterium USM2 and PhaC_Cn/RePhaC1 from Cupriavidus necator/R. eutropha, have been analysed and the crystal structures of the C-domains have been determined. PhaC_Cn/RePhaC1 was also studied by small angle X-ray scattering (SAXS) analysis. Models have been proposed for dimerization, catalysis mechanism, substrate recognition and affinity, product formation and product egress route. The assays based on amino acid substitution by mutagenesis have been useful to validate the hypothesis on the role of amino acids in catalysis and in accommodation of bulky substrates, for the synthesis of PHB co-polymers and medium chain length-PHA polymers with optimized chemical properties.

Leishmania species are parasitic protozoans which cause leishmaniasis affecting millions of people worldwide. Sterols are important components of plasma and organellar membranes and serve as precursors for the synthesis of signaling molecules. In contrast to animals, Leishmania do not produce cholesterol but instead synthesize ergostane-based sterols. C14-demethylase is a key enzyme involved in the biosynthesis of sterols in Leishmania parasites and an important drug target. Its inactivation leads to multiple defects including increased plasma membrane fluidity, mitochondrion dysfunction, hypersensitivity to stress and reduced virulence. In this study, we revealed a novel role for sterol synthesis in the maintenance of RNA stability and translation. Sterol alteration in C14-demethylase knockout mutant leads to increased RNA degradation, reduced translation and impaired heat shock response. Thus, sterol biosynthesis plays an unexpected role in global gene regulation in Leishmania parasites.