Effect of copper ions on the associations of <i>Azospirillum</i> bacteria with wheat seedlings (<i>Triticum aestivum</i> L.)

The physiological and biochemical activity of plant–microbial associations enables them to determine the mobility, bioavailability, and accumulation of heavy metals in plant tissues. These abilities are the basis for the use of plants and their associated microorganisms in the development of approaches that ensure both the prevention of the ingress of toxic metals into food crops and the extraction of pollutants from polluted soils by using phytoremediation technologies. Whether plant–microbial complexes are used successfully depends on the knowledge of how specific organisms interact with heavy metals. We evaluated the effect of copper ions on common wheat (Triticum aestivum L.) inoculated with three plant-growth-promoting rhizobacteria (PGPR) of the genus Azospirillum. We analyzed the growth variables of 14-day-old wheat seedlings, the content of photosynthesis pigments, the activity of plant oxidoreductases, and the accumulation of copper by plant tissues. All strains more or less compensated for copper toxicity to seedling development and increased metal accumulation in roots and shoots. Copper affected the photosynthetic apparatus of the inoculated plants, primarily by decreasing the content of chlorophyll b. An analysis of the activity of plant oxidoreductases (peroxidases and phenoloxidases), which are involved in the physiological responses of plants to pollutant stress, showed strain-specific dependence and a significant effect of copper on the inoculated plants. Overall, the obtained results clearly show that the effect of Azospirillum on the physiological and biochemical status of wheat is diverse. The compensatory effect of bacteria on copper toxicity and the simultaneous increase in metal accumulation in plant tissues can be considered as mutually exclusive crop-production aspects associated with the growing of food plants in heavy-metal-polluted areas

Моделювання процесу формування нанопористої структури вуглецевих матеріалів для електродів електрохімічних конденсаторів

The paper presents the results of predicting the physical properties of nanoporous carbon materials during synthesis with their subsequent use as an electrode material for electric double-layer capacitors. It has been established a multilayer neural network can be used to predict the sorption properties of nanoporous carbon materials. A multilayer neural network confirms the experimental dependences of the characteristics of nanoporous carbon materials porous structure on the technological conditions of its obtaining.У роботі представлені результати прогнозування фізичних властивостей нанопористих вуглецевих матеріалів в процесі отримання з подальшим застосуванням їх як електродного матеріалу для електрохімічних конденсаторів, заряд яких накопичується в подвійному електричному шарі. Встановлено, що багатошарову нейронну мережу можна використовувати для прогнозування сорбційних властивостей нанопористих вуглецевих матеріалів, яка підтверджує експериментальні залежності характеристик їх пористої структури від технологічних умов отримання

Hybrid PCL/CaCO3 scaffolds with capabilities of carrying biologically active molecules : synthesis, loading and in vivo applications

Designing advanced biomaterials for tissue regeneration with drug delivery and release functionalities remains a challenge in regenerative medicine. In this research, we have developed novel composite scaffolds based on polymeric polycaprolactone fibers coated with porous calcium carbonate structures (PCL/CaCO3) for tissue engineering and have shown their drug delivery and release in rats. In vivo biocompatibility tests of PCL/CaCO3 scaffolds were complemented with in vivo drug release study, where tannic acid (TA) was used as a model drug. Release of TA from the scaffolds was realized by recrystallization of the porous vaterite phase of calcium carbonate into the crystalline calcite. Cell colonization and tissue vascularization as well as transplantability of developed PCL/CaCO3 + TA scaffolds were observed. Detailed study of scaffold transformations during 21-day implantation period was followed by scanning electron microscopy and X-ray diffraction studies before and after in vivo implantation. The presented results demonstrate that PCL/CaCO3 scaffolds are attractive candidates for implants in bone regeneration and tissue engineering with a possibility of loading biologically active molecules and controlled release

Photodynamic opening of the blood-brain barrier and pathways of brain clearing

A new application of the photodynamic treatment (PDT) is presented for the opening of blood-brain barrier (BBB) and the brain clearing activation that is associated with it, including the use of gold nanoparticles as emerging photosensitizer carriers in PDT. The obtained results clearly demonstrate 2 pathways for the brain clearing: (1) using PDT-opening of BBB and intravenous injection of FITC-dextran we showed a clearance of this tracer via the meningeal lymphatic system in the subdural space; (2) using optical coherence tomography and intraparenchymal injection of gold nanorods, we observed their clearance through the exit gate of cerebral spinal fluid from the brain into the deep cervical lymph node, where the gold nanorods were accumulated. These data contribute to a better understanding of the cerebrovascular effects of PDT and shed light on mechanisms, underlying brain clearing after PDT-related opening of BBB, including clearance from nanoparticles as drug carriers

Impact of irrigation with As-rich groundwater on soil and crops: a geochemical case study in Maldah District, West Bengal

The distribution of As was explored in soils and crops in order to investigate the influence of irrigation with As rich groundwater on the soil–plant system, and to determine its impact on the environment and human health. The study was carried out in an intensively cultivated agricultural area of the Bengal Delta Plain, West Bengal, India. Soils, plants, and irrigation water from adjacent rice and wheat fields were analysed for As and other elements. Irrigation water has concentrations of up to 780 μg L−1 As in the study area. Rice and wheat grains are not contaminated by As (about 0.3 and 0.7 mg kg−1, respectively), but concentrations in rice roots were found to be 169–178 mg kg−1 As, which is more than 20 times higher than value of 7.7 mg kg−1 measured at the uncontaminated reference site. This high content is due to an Fe-rich plaque which coats the rice roots. A significant increase of As concentration was registered also in the stems of the rice plants irrigated with As rich groundwater (6.55–7.06, relative to 0.36 mg kg−1 As in the reference plant). Arsenic concentration in the uppermost soil layers of the rice paddy field (38 mg kg−1) was found to be roughly twice as high as in the soil of the less intensively watered wheat field (18 mg kg−1) and more than 5 times higher than in the soil of a rice paddy irrigated with uncontaminated water (7 mg kg−1). In both soil sections As contents decreased downwards to 11 mg kg−1 at 100–110 cm depth, approaching the background value of 5–10 mg kg−1 measured in an unaffected reference area. Sequential extraction experiments show that most of the mobile As in soils is bound to Fe-oxides. Though no tight correlation was found between Fe and As in the bulk soil samples, these experiments coupled with μ-synchrotron radiation XRF analysis of single soil particles from the rice paddy also indicates that additional to the mobile fraction a substantial part of As is immobilized in (chiefly Fe bearing) silicates. In rice soil some As was also found in the sulphide-bearing phase of the extraction© Elsevie