Photosynthetic pigments and phytochemical activity of photosynthetic apparatus of maize (Zea mays L.) leaves under the effect of thiamethoxam

In the last decade, neonicotinoid insecticides have been actively used to protect plants from pests. Moreover, their effect on the plants, in particular on the state of photosynthetic pig-ments, has been studied paucity. In the present work, it was shown for the first time that treatment of maize (Zea maysL.) leaves with a thiamethoxam (TMX) insecticide leads to a decrease in the functional activity of photosystem II and a decrease in the energyzation of thylakoid membranes. In addition, the effect of thiamethoxam depends on the genotype of maize. The aim of the work was to study the effect of thiamethoxam pesticide on photosynthetic pigments and the photochemical activi-ty of the photosynthetic apparatus of maize leaves of two genotypes. The experiments were carried out in 2018-2019.The object of the study was samples of maize leaves of the inbred line zppl 225 and hybrid zp 341 with high rates of germination, grain quality and yield (Institut za kukuruz “Zemun Polje”, Belgrade, Serbia). The seeds were germinated until the roots appeared (length not less than 5mm),after which they were planted in the soil (vermiculite:chernozem mixture, 1:1) and grown under 16-hour daylight at a constant temperature of 25 С. When the third trueleaf appeared (more than 4 cm in length), the plants were sprayed with a TMX solution at a concentration of 0.2 mg/l. Plants grown under similar conditions without TMX spraying were used as controls. The measurements were carried out when the fifth true leaf reached a size of 12-14 cm.The content of photosynthetic pigments (chlorophyll a, b and carotenoids) was determined spectrophotometrically in 100% acetone extract and calculated using the Holm-Wetstein formula. A change in the confor-mation of carotenoid molecules was recorded by Raman spectroscopy.Light-induced kinetics of prompt fluorescence (PF), delayed fluorescence (DF) and modulated reflection at = 820 nm (MR) were recorded simultaneously using a multifunctional plant efficiency analyzer M-PEA-2 (Hansatech Instruments, Great Britain). PF induction curves (OJIP curves) were analyzed using a standard JIP-test. It was found that in the phase of the fifth true leaf, in the inbred line zppl 225, the chlorophyll content in the presence of TMX decreased from 0.74 to 0.61 mg/g: the amount of chlorophyll a decreased by 17 %, chlorophyll b by 24 %. In contrast, no changes in pigment composition were detected in the leaves of the zp 341 hybrid when exposed to TMX. The OJIP curves of the control and TMX-treated leaves had a typical curve with characteristic O-J, J-I, and I-P phases, which re-flected the processes of sequential reduction of carriers in the electron transport chain of photosyn-thesis (ETC) between two photosystems. The effect of the pesticide onthe leaves of two maize geno-types was manifested in a decrease in the functional state of photosystem II, determined by the fluo-rescence parameter (PIABS), which was obtained based on the analysis of OJIP curves using the JIP-test. Comparison of PIABSin the control and under the influence of TMX revealed statistically sig- 67nificant (p < 0.05) differences: in the leaves of zppl 225 and zp 341 samples treated with TMX, the PIABSparameter decreased by 29 and 24%, respectively. Changes in the fast phase of delayed fluo-rescence, associated with a decrease in the energyzation of the thylakoid membrane upon exposure to TMX, were detected in the leaves of maize. An analysis of the maximum oxidation and reduction rates of P700 (MR kinetics) indicates a decrease in the acceptor pool on the acceptor side of PSI in zppl 225 leaves when exposed to TMX. It was found that the reaction centers (RCs) of PSI zp 341 showed resistance to TMX (no change in the redox transformations of P700). TMX caused changes in the conformation of carotenoid molecules, but did not change their content in the leaf. The pro-posed combination of methods for prompt fluorescence, delayed fluorescence, modulated reflection at = 820 nm and Raman spectroscopy can be the basis for the formation of an effective technology for the diagnosis of early defects of photosynthetic pigments when pesticides enter an intact plant

Microsurgical head and neck tissue repair by visceral mini-autografting

Objective. To minimize surgical trauma in patients with head and neck tumors during microsurgical plasty with visceral autografts.Subjects and methods. Clinical experience has been gained in the treatment of 53 patients with locally advanced craniofascial (n = 27) and oropharyngeal (n = 36) cancers. Abdominal organs were used for plastic closure of extensive defects after surgical resection. Paraumbilical incision allowing for an adequate approach into the abdominal cavity with minimal external trauma in the anterior abdominal wall was chosen as an access procedure. Video-assisted techniques were used to excise the midline aponeurosis. Donor organs, such as the omentum, greater curvature of the stomach, transverse colon, small intestine) were taken through a mini-laparotomic incision to the anterior abdominal wall, then the vascular pedicle was exposed and a visceral autograft was made. After forming and cutting off the autograft, organ anastomoses were created extracorporeally.Results. Mini-access surgery could be completed in 50 of the 53 cases (4 patients had previously undergone abdominal interventions). Omental (n = 26), colo-omental (n = 15), gastro-omental (n = 7), and entero-omental (n = 5) flaps were made and prepared for autografting. No intra- or postoperative abdominal complications were found.Conclusion. Minimally invasive technologies used to create visceral authografts for head and neck tissue repair can minimize surgical trauma and reduce treatment duration. The indications for this access are the debilitating state of a cancer patient or the young age of a patient who does not wish to have an additional scar in the donor region

Многокурсовая фотодинамическая терапия при базально-клеточном раке кожи центральной зоны лица (клиническое наблюдение)

The results of an 11-year clinical observation and treatment of a patient with stage II basal cell carcinoma of the face (Т2N0M0) are presented. History of the illness is associated with a long (from 2001 to 2008) inadequate treatment, due to the incorrect diagnosis. After the proper diagnosis was established, from 2008 to 2019 at the Center for Laser and Photodynamic Diagnostics and Tumor Therapy of P.A. Herzen Moscow Oncology Research Center, the patient underwent organ-preserving treatment using the multi-course photodynamic therapy (PDT) and drug targeted therapy. In total, 23 courses of PDT were conducted with photosensitizers of the chlorin series and 5-aminolevulinic acid during this period. Since 2018, the patient is in the process of targeted drug treatment with Vismodegib. In the course of targeted drug treatment, a follow-up examination in 2019 revealed continued growth of the residual tumor, and another course of PDT was carried out. Throughout the observation period, the patient tolerated the treatment well, without complications, with a good quality of life and satisfactory cosmetic effect.Приведены результаты 11-летнего клинического наблюдения и лечения пациентки с базальноклеточным раком кожи лица II стадии (Т2N0M0). Анамнез течения заболевания связан с длительным (с 2001 по 2008 гг.) неадекватным лечением, вследствие отсутствия правильного диагноза. После установки диагноза, с 2008 по 2019 гг. в МНИОИ им. П.А. Герцена в Центре лазерной и фотодинамической диагностики и терапии опухолей пациентке проведено органосохраняющее лечение методом многокурсовой фотодинамической терапии (ФДТ) и лекарственной таргетной терапии. Проведено 23 курса ФДТ с фотосенсибилизаторами хлоринового ряда и 5-аминолевулиновой кислоты. С 2018 г. пациентка находится в процессе лекарственного лечения таргетной терапией висмодегибом. На фоне таргетного лекарственного лечения при контрольном осмотре в 2019 г. выявлен продолженный рост остаточной опухоли, проведен очередной курс ФДТ. Весь срок наблюдения пациентка переносила лечение хорошо, без осложнений с хорошим качеством жизни и удовлетворительным косметическим эффектом

Phytoplankton in the Nhatrang Bay, South China Sea

Species composition, phytoplankton abundance, and relative yield of variable fluorescence (F_v/F_m) were determined in the mesotrophic Nhatrang Bay in October-November 2004. Species diversity (250 taxonomic units) and heterogeneity of the phytoplankton structure were high. With respect to number of species and their abundance, diatoms prevailed. In selected parts of the bay, dinoflagellates dominated. Average biomass in the water column under 1 m**2 (Bt) varied from 2.3 to 64.4 mg C/m**3 (av. 31.0 mg C/m**3). Bt values were the lowest at stations nearest to the river mouth. Seaward, Bt increased. Bt values increased with depth at some stations and decreased at others. In surface layers biomass was lower than that in the underlying waters. F_v/F_m values ranged from 0.10 to 0.64 (av. 0.49). The lowest F_v/F_m values were observed in the area close to the seaport. Over greater part of the bay, F_v/F_m values were higher than 0.47. Such values are indicative of relatively high potential of photosynthetic activity of phytoplankton. Abundance and species diversity were higher than those in the dry season (March-April)