Phototropin interactions with SUMO proteins

The disruption of the sumoylation pathway affects processes controlled by the two phototropins (phots) of Arabidopsis thaliana, phot1 and phot2. Phots, plant UVA/blue light photoreceptors, regulate growth responses and fast movements aimed at optimizing photosynthesis, such as phototropism, chloroplast relocations and stomatal opening. Sumoylation is a posttranslational modification, consisting of the addition of a SUMO (SMALL UBIQUITIN-RELATED MODIFIER) protein to a lysine residue in the target protein. In addition to affecting the stability of proteins, it regulates their activity, interactions and subcellular localization. We examined physiological responses controlled by phots, phototropism and chloroplast movements, in sumoylation pathway mutants. Chloroplast accumulation in response to both continuous and pulse light was enhanced in the E3 ligase siz1 mutant, in a manner dependent on phot2. A significant decrease in phot2 protein abundance was observed in this mutant after blue light treatment both in seedlings and mature leaves. Using plant transient expression and yeast two-hybrid assays, we found that phots interacted with SUMO proteins mainly through their N-terminal parts, which contain the photosensory LOV domains. The covalent modification in phots by SUMO was verified using an Arabidopsis sumoylation system reconstituted in bacteria followed by the mass spectrometry analysis. Lys 297 was identified as the main target of SUMO3 in the phot2 molecule. Finally, sumoylation of phot2 was detected in Arabidopsis mature leaves upon light or heat stress treatment

Electrocatalytic reduction of chloroform on nanostructured silver electrodes.

Postępująca degradacja środowiska naturalnego stanowi realne zagrożenie dla ekosystemu ziemskiego. Pośród najbardziej niebezpiecznych zanieczyszczeń szczególne miejsce zajmują halogenki alifatyczne. Związki te, wysoce toksyczne i mutagenne, zazwyczaj nie poddają się całkowitej degradacji. Pośród szeregu metod stosowanych do eliminacji halogenków organicznych ze środowiska naturalnego szczególnie obiecujące wydają się być metody redukcyjne prowadzone na elektrodach nanostrukturalnych. Elektrody srebrne charakteryzują się niezwykłymi właściwościami elektrokatalitycznymi, które polepszają się wraz ze wzrostem chropowatości powierzchni elektrody. Celem niniejszej pracy była synteza elektrod pokrytych nanodrutami i nanostożkami srebrnymi, zbadanie właściwości elektrokatalitycznych zsyntezowanych elektrod i porównanie ich z właściwościami polerowanej elektrody Ag. Elektrody pokryte nanostrukturami otrzymano przy wykorzystaniu obustronnie otwartych matrycach z porowatego tlenku glinu. Dla zsyntezowanych elektrod wykonano testy postarzania, wyznaczono parametry kinetyczne oraz granicę wykrywalności (LOD) i oznaczalności (LOQ) chloroformu.The ongoing degradation of natural environment poses a real threat to the global ecosystem. Aliphatic halides are ranked high among the most dangerous contaminants. These compounds, known for their toxicity and mutagenicity, do not undergo complete degradation. Among methods for dehalogenation of organic halides, particularly promising are the reduction techniques conducted on nanostructured electrodes. Silver electrodes possess extraordinary electrocatalytic properties towards dehalogenation of chlorinated volatile compounds, that improve with the rise of the surface roughness of the electrode. The scope of this study was to fabricate electrodes covered with silver nanocones and nanowires and investigate of electrocatalytic behaviour of the synthesized electrodes in comparison to the polished silver bulk electrode. Nanostructured electrodes were obtained with the use of through-hole membranes of nanoporous alumina. Aging tests were conducted on the synthesized electrodes. Additionally, the kinetic parameters of the electrocatalytic reduction of chloroform were determined as well as the values of LOD (limit of detection) and LOQ (limit of quantification)

Upregulation of GLRs expression by light in Arabidopsis leaves

BACKGROUND: Glutamate receptor-like (GLR) channels are plant homologs of iGluRs, animal ionotropic glutamate receptors which participate in neurotransmission. GLRs mediate plant adaptive processes and photomorphogenesis. Despite their contribution to light-dependent processes, signaling mechanisms that modulate GLR response to light remain unknown. Here we show that leaf expression of 7 out of 20 Arabidopsis GLRs is significantly up-regulated by monochromatic irradiation. RESULTS: Our data indicates that both red and blue light stimulate the expression of selected AtGLRs. Using a photosynthesis inhibitor and different irradiation regimes, we demonstrated that retrograde signaling from photosystem II is unlikely to be involved in light-dependent GLR up-regulation. Analysis of transcriptional patterns in mutants of key photoreceptors allowed us to observe that both phytochromes and cryptochromes are likely to be involved in the control of light-dependent up-regulation of AtGLR expression, with phytochromes playing a clearly dominating role in this process. CONCLUSIONS: In mature Arabidopsis leaves, phytochromes, assisted by cryptochromes, mediate light-driven transcriptional up-regulation of several genes encoding GLR proteins. Since GLRs are known to be involved in a wide range of plant developmental processes our results provide mechanistic insight into how light may influence plant growth and development. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12870-022-03535-7

Tri- and Pentacyclic Azaphenothiazine as Pro-Apoptotic Agents in Lung Carcinoma with a Protective Potential to Healthy Cell Lines

The phenothiazine derivatives, tricyclic 10H-3,6-diazaphenothiazine (DPT-1) and pentacyclic 7-(3′-dimethylaminopropyl)diquinothiazine (DPT-2), have recently been shown to exhibit promising anticancer activities in vitro. In this report, we demonstrated that DPT-1 and DPT-2 could be pro-apoptotic agents in lung carcinoma, the human lung carcinoma A549 and non-small lung carcinoma H1299, in the range of IC50 = 1.52–12.89 µM, with a protective potential to healthy cell lines BEAS-2B and NHDF. The compounds showed higher activity in the range of the tested concentrations and low cytotoxicity in relation to normal healthy cells than doxorubicin, used as the reference drug. The cytostatic potential of DPT-1 and DPT-2 was demonstrated with the use of MTT assay. Cell cycle analysis via flow cytometry using Annexin-V assay showed the pro-apoptotic and pro-necrotic role of the studied diazaphenothiazines in the cell cycle. DPT-1 and DPT-2 initiated a biological response in the investigated cancer models with a different mechanism and at a different rate. Based on these findings, it can be concluded that DPT-1 and DPT-2 have potential as chemotherapeutic agents

BQ123 Stimulates Skeletal Muscle Antioxidant Defense via Nrf2 Activation in LPS-Treated Rats

Little is understood of skeletal muscle tissue in terms of oxidative stress and inflammation. Endothelin-1 is an endogenous, vasoconstrictive peptide which can induce overproduction of reactive oxygen species and proinflammatory cytokines. The aim of this study was to evaluate whether BQ123, an endothelin-A receptor antagonist, influences the level of TNF-α, IL-6, SOD-1, HO-1, Nrf2 mRNA, and NF-κB subunit RelA/p65 mRNA in the femoral muscle obtained from endotoxemic rats. Male Wistar rats were divided into 4 groups (n=6) and received iv (1) saline (control), (2) LPS (15 mg/kg), (3) BQ123 (1 mg/kg), (4) BQ123 (1 mg/kg), and LPS (15 mg/kg, resp.) 30 min later. Injection of LPS led to significant increase in levels of RelA/p65 mRNA, TNF-α, and IL-6, while content of SOD-1, HO-1, and Nrf2 mRNA was unchanged. Administration of BQ123 prior to LPS challenge resulted in a significant reduction in RelA/p65 mRNA, TNF-α, and IL-6 levels, as well as markedly elevated concentrations of SOD-1, HO-1, and Nrf2 mRNA. BQ123 appears to enhance antioxidant defense and prevent production of TNF-α and IL-6 in skeletal muscle of LPS-treated rat. In conclusion, endothelin-A receptor antagonism exerts significant impact on the skeletal muscle favouring anti-inflammatory effects and protection against oxidative stress