Copper Stress Enhances the Lignification of Axial Organs in Zinnia elegans

Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution in urban and rural areas is still increasing, which determines the actuality of studying plants’ reactions to pollutants. Zinnia was not sufficiently studied in this regard, so the aim of our research was to identify morphophysiological changes in this species under excess copper concentration in the soil. For this, we treated a growth substrate with 200 µM CuSO4 solution for 20 days. At the end of the treatment, several morphological, biochemical, and molecular genetic traits were evaluated: the root and the shoot size; the concentration of H2O2 and malondialdehyde (MDA), as indicators of stress; the amount of the phenolic compounds and lignin; and the level of the expression of genes, which encoded their biosynthesis. The Cu amount in the substrate and zinnia organs was quantified using atomic-absorption spectroscopy; hydrogen peroxide, MDA, and phenolic compounds were determined spectrophotometrically, while the amount of lignin was determined according to Klason. Real-time PCR was used for estimation of the gene-transcription level. Lignin in tissues was visualized by fluorescent microscopy. In experimental plants, Cu accumulation was higher in the root than in the stem. This caused an increase in stress markers and a decrease in the root and stem lengths. For the first time for zinnia, it was shown that for several genes—4-coumarate-CoA ligase (4CL), cinnamoyl alcohol dehydrogenase (CAD), and class III peroxidase (PRX)—the level of expression increased under copper treatment. The rise of the transcripts’ amount of these genes was accompanied by a thickening and lignification of the cell walls in the metaxylem vessels. Thus, the adaptation of zinnia to the excess Cu in the growth medium was associated with the metabolic changes in the phenylpropanoid pathway. As a result, the lignification increased in the root, which led to the accumulation of Cu in this organ and limited its translocation through the xylem to the stem, which provided plant growth. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 22-24-00817Funding: This research was supported by the Russian Science Foundation, project no. 22-24-00817, https://rscf.ru/project/22-24-00817/, accessed date: 17 July 2022

Diagnosis of Cervical Cancer Using Raman Spectroscopy

The aim of the study was to develop a method of detecting cervical cancer using Raman spectroscopy in the examination of biopsy and surgical material. Significant differences in the spectral characteristics between the tissues of the intact cervix and tissues with squamous cell carcinoma of the cervix have been revealed. Intensity of fluorescence in cervical cancer was higher than in intact cervical tissue.     Keywords: cervical cancer, squamous cell carcinoma, diagnosis of cervical cancer, fluorescence in cervical cancer, Raman spectroscopy for the diagnosis of cervical cance

Plant Growth Promoting Activity and Metal Tolerance of Bacteria Isolated from Rhizosphere of the Orchid Epipactis atrorubens Growing on Serpentine Substrates of the Middle Urals

В статье представлены данные, полученные при изучении бактерий, выделенных из ризосферы орхидеи Epipactis atrorubens (Hoffm.) Besser. Проведен сравнительный анализ некоторых морфологических, физиологических и биохимических характеристик ризобактерий растений, произрастающих в двух биотопах на серпентинитовых породах: в естественном лесном фитоценозе (фоновый участок) и на отвале после добычи асбеста (Свердловская область, Средний Урал). Оценка ростстимулирующей (PGP) активности выделенных штаммов не показала достоверных различий между исследованными участками по способности ризобактерий к синтезу индолил‑3-уксусной кислоты (ИУК) и солюбилизации фосфатов. Однако доля изолятов, способных к азотфиксации, была выше в ризосфере E. atrorubens, произрастающего на отвале, по сравнению с фоновым местообитанием. Устойчивость изолятов к тяжелым металлам оценивали по максимальной концентрации металла (400, 600 и 1000 мг/л соответственно для Ni, Cu и Zn), при которой отмечался рост бактерий. Показано, что ризобактерии с отвала оказались более устойчивыми к повышенным концентрациям металлов по сравнению с естественным лесным фитоценозом. На основе молекулярно-генетического анализа изолятов с наиболее выраженной PGP‑активностью (ИУК >1,0 мг/л; PO4 3- >50,0 мг/л) обнаружено сходство между изученными местообитаниями по родовой принадлежности ризобактерий E. atrorubens: выделенные штаммы принадлежали преимущественно к родам Buttiauxella и Pseudomonas. В модельных экспериментах протестирована ростстимулирующая способность четырех отобранных штаммов на семенах циннии. Инокуляция семян Pseudomonas sp. и Buttiauxella sp. не оказывала значимого влияния на их всхожесть, однако Buttiauxella sp. способствовала увеличению длины проростков в сравнении с контролем (в среднем на 25 %). Сделано предположение, что отобранные изоляты ризобактерий E. atrorubens, благодаря их ростстимулирующей активности и металлоустойчивости, могут способствовать натурализации орхидеи на техногенно нарушенной территорииThe article presents data obtained in the study of bacteria isolated from the rhizosphere of the orchid Epipactis atrorubens (Hoffm.) Besser. Analysis was carried out to compare some morphological, physiological, and biochemical characteristics of plant rhizobacteria growing on serpentine rocks in two biotopes: in the natural forest community (control habitat) and on the asbestos mine dump (the Sverdlovsk region, Middle Urals). An assessment of the plant growth promoting (PGP) activity of the isolated strains did not show significant differences in the ability of rhizobacteria to synthesize indol‑3-acetic acid (IAA) and solubilize phosphates between the study sites. However, the proportion of isolates capable of nitrogen fixation was higher in the rhizosphere of E. atrorubens growing on the dump compared to the control habitat. The tolerance of isolates to heavy metals was assessed by the maximum metal concentration (400, 600, and 1000 mg/L, respectively, for Ni, Cu, and Zn) at which bacterial growth was observed. Rhizobacteria from the dump were found to be more resistant to elevated concentrations of metals compared to their counterparts from the natural forest community. The molecular genetic analysis of isolates with the highest PGP‑activity (IAA >1.0 mg/L; PO4 3- >50.0 mg/L) revealed that most of the E. atrorubens rhizobacteria in both habitats belonged to the genera Buttiauxella and Pseudomonas. In model experiments, the PGP ability of four selected strains was tested on zinnia seeds. Seed inoculation with Pseudomonas sp. and Buttiauxella sp. did not have any significant effect on their germination; however, Buttiauxella sp. contributed to the increase in the length of seedlings compared with the control (by 25 %, on average). It has been suggested that the selected isolates of E. atrorubens rhizobacteria, due to their growth promoting activity and metal tolerance, can facilitate naturalization of the orchid in an industrially disturbed are

Ammoniated electron as a solvent stabilized multimer radical anion

The excess electron in liquid ammonia ("ammoniated electron") is commonly viewed as a cavity electron in which the s-type wave function fills the interstitial void between 6-9 ammonia molecules. Here we examine an alternative model in which the ammoniated electron is regarded as a solvent stabilized multimer radical anion, as was originally suggested by Symons [Chem. Soc. Rev. 1976, 5, 337]. In this model, most of the excess electron density resides in the frontier orbitals of N atoms in the ammonia molecules forming the solvation cavity; a fraction of this spin density is transferred to the molecules in the second solvation shell. The cavity is formed due to the repulsion between negatively charged solvent molecules. Using density functional theory calculations for small ammonia cluster anions in the gas phase, it is demonstrated that such core anions would semi-quantitatively account for the observed pattern of Knight shifts for 1-H and 14-N nuclei observed by NMR spectroscopy and the downshifted stretching and bending modes observed by infrared spectroscopy. It is speculated that the excess electrons in other aprotic solvents (but not in water and alcohols) might be, in this respect, analogous to the ammoniated electron, with substantial transfer of the spin density into the frontier N and C orbitals of methyl, amino, and amide groups forming the solvation cavity.Comment: 34 pages, 12 figures; to be submitted to J Phys Chem