Increase In Dehydrogenase Activity Research Articles

Cyanobacteria-green microalgae consortia enhance soil fertility and plant growth by shaping the native soil microbiome of Capsicum annuum

Alternative solutions to chemical fertilizers that can enhance soil fertility, increase crop yield, promote sustainable agriculture and reduce harmful environmental impacts are urgently required. Microalgal bio-inoculants can improve soil fertility, plant growth and crop yield, yet the response of native soil microbiome to microalgal application remains largely unexplored. A pot experiment was conducted to assess the effects of microalgae (a consortium of cyanobacteria and green microalgae) inoculation on the growth and yield of chili plants, soil fertility and soil microbiome. Our results showed that microalgal inoculation significantly enhanced plant morphometric parameters and increased dehydrogenase activity (p < 0.05). Similarly, soil organic carbon, soil chlorophyll, total polysaccharides and nutrients such as carbon, nitrogen, phosphorus, potassium and manganese were also significantly (p < 0.05) enriched in microalgal treatment groups (50% and 100%) compared to the control. Results showed that microalgal inoculation increased the soil microbial diversity, with the richness being higher in treated soils than in control. Metagenomics analysis revealed a shift in bacterial and fungal community composition with firmicutes, chloroflexi, planctomycetes, proteobacteria, bacillariophyta, basidiomycota and glomeromycota dominating microalgal-treated soils, while actinobacteria, bacteroidetes, and streptomycota dominating control soils. The findings suggested that microalgal bio-inoculation can increase the diversity and composition of native soil microbiomes and enhance soil fertility, growth, and yield in chili plants.

Effect of tire wear particle accumulation on nitrogen removal and greenhouse gases abatement in bioretention systems: Soil characteristics, microbial community, and functional genes

Tire wear particles (TWPs), as predominant microplastics (MPs) in road runoff, can be captured and retained by bioretention systems (BRS). This study aimed to investigate the effect of TWPs accumulation on nitrogen processes, focusing on soil characteristics, microbial community, and functional genes. Two groups of lab-scale bioretention columns containing TWPs (0 and 100 mg g−1) were established. The removal efficiencies of NH4+-N and TN in BRS significantly decreased by 7.60%–24.79% and 1.98%–11.09%, respectively, during the 101 days of TWPs exposure. Interestingly, the emission fluxes of N2O and CO2 were significantly decreased, while the emission flux of CH4 was substantially increased. Furthermore, prolonged TWPs exposure significantly influenced the contents of soil organic matter (increased by 27.07%) and NH4+-N (decreased by 42.15%) in the planting layer. TWPs exposure also significantly increased dehydrogenase activity and substrate-induced respiration rate, thereby promoting microbial metabolism. Microbial sequencing results revealed that TWPs decreased the relative abundance of nitrifying bacteria (Nitrospira and Nitrosomonas) and denitrifying bacteria (Dechloromonas and Thauera), reducing the nitrification rate by 42.24%. PICRUSt2 analysis further indicated that TWPs changed the relative abundance of functional genes related to nitrogen and enzyme-coding genes.

Effects of polystyrene, polyethylene, and polypropylene microplastics on the soil-rhizosphere-plant system: Phytotoxicity, enzyme activity, and microbial community

The widespread presence of soil microplastics (MPs) has become a global environmental problem. MPs of different properties (i.e., types, sizes, and concentrations) are present in the environment, while studies about the impact of MPs having different properties are limited. Thus, this study investigated the effects of three common polymers (polystyrene, polyethylene, and polypropylene) with two concentrations (0.01% and 0.1% w/w) on growth and stress response of lettuce (Lactuca sativa L.), soil enzymes, and rhizosphere microbial community. Lettuce growth was inhibited under MPs treatments. Moreover, the antioxidant system, metabolism composition, and phyllosphere microbiome of lettuce leaves was also perturbed. MPs reduced phytase activity and significantly increased dehydrogenase activity. The diversity and structure of rhizosphere microbial community were disturbed by MPs and more sensitive to polystyrene microplastics (PSMPs) and polypropylene microplastics (PPMPs). In general, the results by partial least squares pathway models (PLS-PMs) showed that the presence of MPs influenced the soil-rhizosphere-plant system, which may have essential implications for assessing the environmental risk of MPs.

Chemical seed treatment and mycorrhizal inoculation provide better development and nutrition of common bean plants.

Chemical seed treatment is an established practice in agriculture to protect crops from soil-borne pathogens and pests. Arbuscular mycorrhizal fungi (AMF) benefit plants by extending soil exploration as well as water and nutrient uptake. The objective of this work was to analyze the effects of combinations of seed treatments with doses of inoculant containing Rhizoglomus intraradices on vegetative development, root colonization and nutrition of Phaseolus vulgaris plants and soil microbiota. Seed treatment benefited the vegetative development and nutrition of beans, with the treatments metalaxyl + fludioxonil + tiabendazole and pyraclostrobin + thiophanate methyl + fipronil standing out regarding the contents of nitrogen (N), phosphorus (P), iron (Fe) and zinc (Zn) of the aerial parts. Mycorrhizal inoculation linearly increased dehydrogenase activity, root biomass and total plant biomass, with increments reaching 27%. There was an interaction between seed treatment and inoculation dose for aboveground biomass and the contents of potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), manganese (Mn) and root colonization, with expressive results for the combination of the two highest doses of inoculant with metalaxyl + fludioxonil + tiabendazole or pyraclostrobin + methylthiophanate + fipronil in the seeds. Chemical seed treatment and mycorrhizal inoculation benefited bean plants and their nutritional status. The best combinations for the bean crop were metalaxyl + fludioxonil + tiabendazole with 41.4mg of the inoculant per 100 seeds and pyraclostrobin + thiophanate methyl + fipronil with 62.1mg of the inoculant per 100 seeds. © 2022 Society of Chemical Industry.

Rhizobacteria helps to explain the enhanced efficiency of phytoextraction strengthened by Streptomyces pactum

The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality. Here, we evaluated how the joint effect of Streptomyces pactum (strain Act12) and inorganic (Hoagland's solution) and organic (humic acid and peat) nutrients affected the phytoextraction practice of cadmium (Cd) and zinc (Zn) by potherb mustard, and the microbial community composition within rhizosphere was also investigated. The results indicated that the nutrients exerted synergistically with Act12, all increasing the plant biomass and Cd/Zn uptakes. The inoculation of Act12 alone significantly increased dehydrogenase activity of rhizosphere soil (P < 0.05), while urease and alkaline phosphatase activities varied in different dosage of Act12. Combined application of microbial strain with nutrients increased enzymatic activities with the elevated dosage of Act12. 16S ribosomal RNA high-throughput sequencing analysis revealed that Act12 inoculation reduced the diversity of rhizosphere bacteria. The Act12 and nutrients did not change dominant phyla i.e., Proteobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria and Acidobacteria, but their relative abundance differed among the treatments with: Peat > Act12 > Humic acid > Hoagland's solution. Comparatively, Sphingomonas replaced Thiobacillus as dominant genus after Act12 application. The increase in the Sphingomonas and Flavisolibacter abundances under Act12 and nutrients treatments gave rise to growth-promoting effect on plant. Our results revealed the important role for rhizosphere microbiota in mediating soil biochemical traits and plant growth, and our approach charted a path toward the development of Act12 combined with soil nutrients to enhance soil quality and phytoextraction efficiency in Cd/Zn-contaminated soils.

Mobilisation of unavailable phosphorus and improvement of pepper P absorption, fruit yield and quality by the wood rot-fungus

Aims P-mobilising microbes may effectively increase soil P availability. These experiments investigated soil P mobilisation and pepper (Capsicum annuum L.) P uptake in response to the wood-rot fungus Fomitopsis palustris CQ2018. Methods F. palustris CQ2018 was incubated in liquid media and soil to study P mobilisation, and pepper plants with fungal inoculation were grown in a greenhouse experiment to observe the agronomic performances. Key results F. palustris CQ2018 secreted protons, organic acids, and phosphatase to convert AlPO4, Ca3(PO4)2, FePO4 and lecithin into soluble P in liquid culture and increased P availability in three soils with pH 5.53, 7.36 and 8.67. It grew in the roots or on the root surfaces, stimulated root growth, increased dehydrogenase activity in the roots, and solubilised water-insoluble P. Soil inoculated with F. palustris CQ2018 exhibited higher Olsen P and phosphatase activity than uninoculated soil, and there was a positive linear correlation between Olsen P and phosphatase activity (r = 0.788). F. palustris CQ2018 increased pepper P uptake and fruit yield in both unfertilised and fertilised soils even under the condition of reduced fertilisers. Fruit quality was also improved by the increase in P, potassium, and vitamin C but decrease in nitrate. Conclusions F. palustris CQ2018 can mobilise soil P and improve plant P uptake and fruit yield and quality in pepper. Implications F. palustris CQ2018 may be developed into a new, effective, and environmentally friendly biofertiliser. Its effect on different plants in various soils needs further study.

Use of combined tools for effectiveness evaluation of tailings rehabilitated with designed Technosol.

Soil and water characteristics and biogeochemical processes can be improved by the application of an integrated technology based on circular economy: designed Technosol. The evaluation of the effectiveness of the superficial application of a designed Technosol, with andic and eutrophic properties, on the rehabilitation of sulfide tailings of a uranium mine (Fé mining area, Spain) was the aim of this study. After 20months of the Technosol application, the tailing rehabilitation status (Rehabilitated tailing) was compared to a non-rehabilitated tailing (Tailing). To assess the rehabilitation of these systems, several properties were analyzed: chemical characteristics of the materials and their leachates, soil enzymatic activities (dehydrogenase, β-glucosidase, acid phosphatase and urease), basal respiration and several plant endpoints from direct and indirect bioassays and pot experiment using Lolium perennse L. and Trifolium pratense L.. Potentially toxic concentrations of Co, Mn and Ni were identified in both available fraction and leachates, pointing out the serious environmental risk posed by the tailing. The improvement of overall physicochemical properties in the rehabilitated tailing materials (e.g., decrease of thehazardous element concentrations in leachates and available fraction, and improvement of thefertility and structure) allowed a quick plant cover with pasture species and provided a suitable habitat for active microbial community (evaluated by increasing dehydrogenase activity and basal respiration). This improvement in the rehabilitated tailing contributed to a significant decrease in the ecotoxicological risk and the spread of hazardous elements. The field application of this specific Technosol was a promising and lasting solution for rehabilitation of this type of tailings.

Effect of Long-Term Organic Fertilization in Flooded Rice Soil on Phosphorus Transformation and Phosphate Solubilizing Microorganisms

Phosphorus (P) is a major limiting factor for plant growth. Long-term organic fertilization increases P availability by improving soil microbial and chemical properties. To study this, rice was grown under different treatments, namely, control, farmyard manure (FYM), green manure (GM), FYM + GM (1:1) (FYGM), FYM + Azolla (1:1) (FYAZ), rice straw (5 t ha−1) + GM (GMRSF), Azolla + GM (1:1) (GMAZ) and rice straw (2.5 t ha−1) + GM (GMRSH), with the aim of comparative evaluation of microbiological and chemical changes occurring in the rice soil after 15 years of rice-fallow cycles. The results showed that organic fertilization increased dehydrogenase activity by 12–50% over the control. Both acid (166.1 μg PNP g−1 h−1) and alkaline phosphatase (46.1 μg PNP g−1 h−1) activities were found highest in GMRSH. Long-term application of organic fertilization increased the pools of active/labile C (microbial biomass carbon, readily mineralizable carbon), N (microbial biomass nitrogen) and P (microbial biomass phosphorus) in the soil. Bacterial and fungal populations were observed higher in the FYM treatment than in the control. However, the populations of phosphate solubilizing bacteria (PSB) and fungi (PSF) were observed highest in GMRSH and FYAZ, respectively. Non-occluded Al and Fe-P (125.94 kg ha−1) was highest in GMRSH, while occluded P (6.46 kg ha−1) was highest in GMRSF. Thus, long-term (15 years) organic fertilization improves PSB and PSF populations, contributing to better P transformation in the soil. GMRSH and GMRSF treatments were found to be effective organic fertilization in increasing enzymatic activities, available phosphate fractions and microbial biomass in soil.

Reduction of heavy metals bioaccumulation in sorghum and its rhizosphere by heavy metals-tolerant bacterial consortium

A consortium of three heavy metals tolerant-plant growth promoting bacteria (HMT-PGPB) (Bacillus cereus MG257494.1, Alcaligenes faecalis MG966440.1 and Alcaligenes faecalis MG257493.1) was tested for its beneficial effects on microbial activities in sorghum’ rhizosphere (Sorghum vulgare L.). Moreover their ability to reduce heavy metals bioaccumulation in soil and plant during two successive experiments achieved in vitro and green-house. Firstly, the activities of HMT-PGPB consortium were estimated in vitro under mixture of four heavy metals (copper, cadmium, lead, zinc) at two concentrations (1000 and 1500 mgL−1), to confirm its heavy metal tolerance and plant growth promoting ability, then applied as a biofertilizer for sorghum cultivated in soil contaminated with heavy metals. In vitro results, no antagonism among the tested stains was observed and the HMT-PGPB consortium produced all estimated compounds. Greenhouse results proved that the inoculation of sorghum with HMT-PGPB consortium enhanced the microbial activities like increasing dehydrogenase activity (DHA), reduction of heavy metal bioaccumulation in roots and plants and regulate heavy metals bioaccumulation factor (BAF) in rhizosphere and plant. Moreover, the inoculation of sorghum with HMT-PGPB consortium increased the microbial activities and reduced the accumulation of heavy metals in soil, besides decrease BAF values in rhizosphere and plant. The importance of this study, is that enable us to cultivate the contaminated soils with heavy metals and not neglect large areas of such soils with reducing the environmental pollution, through the inoculation of plants by bacterial consortia, that can remove the polluting elements and at the same time stimulate plant growth.

Effect of Co-contamination by PAHs and Heavy Metals on Bacterial Communities of Diesel Contaminated Soils of South Shetland Islands, Antarctica.

Diesel oil is the main source of energy used in Antarctica. Since diesel is composed of toxic compounds such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, it represents a constant threat to the organisms inhabiting this continent. In the present study, we characterized the chemical and biological parameters of diesel-exposed soils obtained from King George Island in Antarctica. Contaminated soils present PAH concentrations 1000 times higher than non-exposed soils. Some contaminated soil samples also exhibited high concentrations of cadmium and lead. A 16S metagenome analysis revealed the effect of co-contamination on bacterial communities. An increase in the relative abundance of bacteria known as PAH degraders or metal resistant was determined in co-contaminated soils. Accordingly, the soil containing higher amounts of PAHs exhibited increased dehydrogenase activity than control soils, suggesting that the microorganisms present can metabolize diesel. The inhibitory effect on soil metabolism produced by cadmium was lower in diesel-contaminated soils. Moreover, diesel-contaminated soils contain higher amounts of cultivable heterotrophic, cadmium-tolerant, and PAH-degrading bacteria than control soils. Obtained results indicate that diesel contamination at King George island has affected microbial communities, favoring the presence of microorganisms capable of utilizing PAHs as a carbon source, even in the presence of heavy metals.

Improving the efficiency of phytoremediation technologies of oil-contaminated soils with the participation of natural sorbents-meliorants

Phytremediation is considered to be a promising and environmentally friendly way to restore oil-contaminated soils. However, the multicomponent nature of oil pollution, its low bioavailability, high stability, hydrophobicity, and toxicity require a comprehensive approach to its implementation. The purpose of the study is to investigate the influence of different types of sorbents-meliorants and their complexes with remediation agents on improvement of the efficiency of phytoremediation technologies of oil-contaminated soils. The study established that the most effective plants for phytoremediation of oil-contaminated soils are Vicia faba var. Minor, Pisum sativum L., Avena sativa L., which are the least exposed to toxic effects of oil among the studied crops, and better adapt to the conditions of oil-contaminated soils. The influence of sorbent-meliorants such as glauconite, zeolite, sawdust, and sunflower husk on the process of phytoremediation of oil-contaminated soils (oil content 5%) was studied. It was proven that sunflower husk is the most promising and available agent for accelerating phytoremediation. The study examined the individual and combined influence of mineral fertilisers, biogenic surfactants of microbial origin, and humates on the growth of Avena sativa plants under conditions of oil pollution, as well as on the process of soil restoration. The best results are obtained by application of the above agents in combination with sunflower husk. This complex (sunflower husk + mineral fertilizers + surfactants of microbial origin / humates) has a positive effect on Avena sativa plants – reduces the rate of oxidative stress, which indicates an improvement in the adaptability of plants to oil-contaminated soil; growth parameters increase; plant biomass accumulation; the total content of chlorophyll a+b increases; and there is an improvement in soil properties by reducing the oil content in soil, reducing phytotoxicity, increasing dehydrogenase activity

Impacts of Compost Application on Controlling Powdery Mildew of Dill(Anethum graveolens L.) Caused by Erysiphe heraclei and its Effect on Soil Fertilityand Productivity

Field experiments were carried out under natural infection in the Experimental Farm of Sids Agricultural Research Station, Agriculture Research Centre, Beni-Sweif governorate in 2017 and 2018 to evaluate the efficiency of compost amended with rock phosphate, gypsum and inoculated by some bioagents (Bacillus subtilis, Trichoderma harzianum and Arbuscular mycorrhizal fungi) in controlling of powdery mildew on dill caused by Erysiphe heraclei and improving its productivity as well as soil fertility using two application methods: soil amendment and/or foliar spray. Overall, all the tested compost treatments were effective in reducing the disease incidence, severity and improve plant growth leading to a significant increase in fresh, dry weights and fruits yield, NPK uptake. Furthermore, all the tested treatments showed significant increases in the defence-related enzymes, peroxidase, polyphenol oxidase and phenols in treated plants as compared with the untreated control. However, compost treatments improve some physical and chemical properties of the soil at the end of growing seasons and increase dehydrogenase activity as a result of enhancing soil fertility.

Soil microbial biomass, activity and community structure as affected by mineral phosphorus fertilization in grasslands

Nutrient availability is an important indicator of nutrient balance and affects soil microbial processes and functions. However, few studies have explored the effect of short-term application of mineral phosphorus (P) on grassland soils. This study evaluated the effect of mineral P fertilization on soil microbial biomass, activity and community composition in the soil of timothy (Phleum pratense L.) swards at two sites (established in 2010) in eastern Canada with P fertilization rates of 0, 20, and 40 kg P ha−1. Soil samples were collected at the top 10 cm three times in 2013 and 2014. Results revealed that P application has significantly increased soil Mehlich-3P and microbial biomass P at both sites tested, but soil microbial biomass C and N were not affected. Phosphorus application has increased dehydrogenase activity, but it had no significant effect on alkaline phosphomonoesterase activity. The total soil bacterial biomass decreased with P application at the Levis site but not at the Normandin site. Permutational multivariate analysis of variance (PERMANOVA) analysis and principal component analysis (PCA) revealed that soil microbial community structure varied between sites and among sampling dates, but was not significantly affected by P fertilization, suggesting that P was not a major limiting factor to soil microbial community structure. We conclude that short-term P application had limited influence on changing the microbial community structure, but did affect the processes of the microorganisms involved in soil P cycling.

Short-Term Effect of Nitrogen Intensification on Aggregate Size Distribution, Microbial Biomass and Enzyme Activities in a Semi-Arid Soil Under Different Crop Types

There is a lack of quantitative assessments available on the effect of agricultural intensification on soil aggregate distribution and microbial properties. Here, we investigated how short-term nitrogen (N) intensification induced changes in aggregate size distribution and microbial properties in a soil of a hot moist semi-arid region (Bangalore, India). We hypothesised that N intensification would increase the accumulation of macroaggregates > 2 mm and soil microbial biomass and activity, and that the specific crop plant sowed would influence the level of this increase. In November 2016, surface (0–10 cm) and subsurface (10–20 cm) soil samples were taken from three N fertilisation treatments, low N (50 kg N ha−1), medium N (75 and 100 kg N ha−1 for finger millet and maize, respectively), and high N (100 and 150 kg N ha−1 for finger millet and maize, respectively). Distribution of water-stable aggregate concentrations, carbon (C) and N dynamics within aggregate size class, and soil microbial biomass and activity were evaluated. The high-N treatment significantly increased the concentration of large macroaggregates in the subsurface soil of the maize crop treatment, presumably due to an increased C input from root growth. Different N fertilisation levels did not significantly affect C and N concentrations in different aggregate size classes or the bulk soil. High-N applications significantly increased dehydrogenase activity in both the surface soil and the subsurface soil and urease activity in the surface soil, likely because of increased accumulation of enzymes stabilised by soil colloids in dry soils. Dehydrogenase activity was significantly affected by the type of crop, but urease activity not. Overall, our results showed that high N application rates alter large macroaggregates and enzyme activities in surface and subsurface soils through an increased aboveground and corresponding belowground biomass input in the maize crop.

Transient increase in cellular dehydrogenase activity after cadmium treatment precedes enhanced production of reactive oxygen species in human proximal tubular kidney cells.

Cadmium is a heavy metal causing toxicity especially in kidney cells. The toxicity is linked also with enhanced oxidative stress leading to cell death. On the other hand, our recent experiments have shown that an increase of total intracellular dehydrogenases activity can also occur in kidney cells before declining until cell death. The aim of the present study, therefore, was to evaluate this transient enhancement in cell viability after cadmium treatment. The human kidney HK-2 cell line was treated with CdCl(2) at concentrations 0-200 microM for 2-24 h and intracellular dehydrogenase activity was tested. In addition, we measured reactive oxygen species (ROS) production, glutathione levels, mitochondrial membrane potential, and C-Jun-N-terminal kinase (JNK) activation. We found that significantly increased dehydrogenase activity could occur in cells treated with 25, 100, and 200 microM CdCl(2). Moreover, the results showed an increase in ROS production linked with JNK activation following the enhancement of dehydrogenase activity. Other tests detected no relationship with the increased in intracellular dehydrogenase activity. Hence, the transient increase in dehydrogenase activity in HK-2 cells preceded the enhancement of ROS production and our finding provides new evidence in cadmium kidney toxicity.

Новая композиция твердофазных модификаций гиалуроновой кислоты протеиногенными аминокислотами HR-2 увеличивает метаболическую активность фибробластов без выраженных пролиферативных эффектов

Гетерополисахарид гиалуронан, являясь ключевым компонентом внеклеточного матрикса, играет важную роль в поддержании определенных физико-химических условий в тканях. Кроме того, гиалуронан может модулировать состояние клеток через взаимодействие с рецепторами и эндоцитоз, однако, эти эффекты недостаточно изучены. Благодаря своим уникальным свойствам, гиалуронан нашел широкое применение в разных областях биомедицины, в частности, активно используется в качестве микроимплантатов в дерму для коррекции возрастных изменений кожи. Вместе с тем, нативный гиалуронан нестабилен при инъекции и подвергается быстрой деградации в ткани, что существенно ограничивает продолжительность вызываемых им эффектов. В данной работе исследуется новая композиция на основе гиалуронана - HR-2, которую отличают ковалентные сшивки между цепями, введенные путем разработанной авторами одностадийной технологии твердофазной модификации полисахаридов. Сшивки препятствуют быстрой деградации гиалуронана. Авторами предложена концепция функционирования гиалуронана в ткани в качестве депо протеиногенных аминокислот и витаминов в целях поддержания биосинтетической активности клеток. Ранее было показано, что сшитый по данной технологии гиалуронан более стабилен в дерме, в связи с чем его действие в качестве депо может быть пролонгировано. В данной работе исследуется влияние на эндотелиоцитоподобные клетки и фибробласты препарата HR-2, представляющего собой новую композицию гиалуроната натрия и сополимера гиалуроновой кислоты с аскорбилфосфатом магния с добавлением глицина, пролина, лизина. В работе проводится сравнение с немодифицированным гиалуронатом натрия. Установлено, что композиция HR-2 в сравнительно высоких концентрациях дозозависимо увеличивает активность дегидрогеназ в фибробластах, что может свидетельствовать о метаболическом их стимулировании. Это отличает препарат HR-2 от нативной гиалуроновой кислоты, ингибирующей в этих же концентрациях метаболическую активность фибробластов. Оба препарата - и HR-2, и нативная гиалуроновая кислота - в малых концентрациях вызывают гормезис-подобный, стимулирующий метаболизм эндотелиоцитов эффект. Цитотоксичность композиции HR-2 ниже нативной гиалуроновой кислоты на обоих клеточных типах. Следует также отметить, что не выявлено достоверного пролиферативного действия обоих препаратов. Полученные в работе новые сведения могут быть использованы для оптимизации режимов применения препаратов гиалуроновой кислоты в биомедицине, с целью достижения максимального терапевтического эффекта и снижения нежелательных последствий его применения. Hyaluronan (HA) is a linear heteropolysaccharide, a key component of the extracellular matrix. It plays an important role in maintaining certain physicochemical conditions in tissues. In addition, hyaluronan can modulate the state of cells through interaction with receptors and endocytosis; however, these effects are not well understood. Due to its unique properties, hyaluronan is widely used in various fields of biomedicine, in particular, as microimplant for correction of age-related skin changes. However, native hyaluronan is unstable when injected and undergoes rapid degradation in the tissue, which significantly limits duration of its effects. In this study, we evaluated a new hyaluronan-based composition, HR-2, which is distinguished by covalent cross-links between the chains. Those cross-links were incorporated using a one-stage technology of solid-phase modification of polysaccharides developed by the authors. The cross-links prevent the rapid degradation of hyaluronan. The authors proposed a concept of injecting hyaluronan into tissue as a depot of proteinogenic amino acids and vitamins in order to maintain the biosynthetic activity of cells. Previously it was shown that hyaluronan produced with this technology was more stable in the dermis, and, therefore, its performance as a depot can be prolonged. In this work, we studied the effect on endotheliocyte-like cells and fibroblasts of HR-2, which is a new composition of sodium hyaluronate and a copolymer of hyaluronic acid with magnesium ascorbyl phosphate supplemented with glycine, proline, and lysine. The study compared HR-2 with unmodified sodium hyaluronate. We found that the composition of HR-2 in relatively high concentrations dose-dependently increased dehydrogenase activities in fibroblasts, that might indicate their metabolic stimulation. This differs HR-2 from native hyaluronic acid, which inhibits the metabolic activity of fibroblasts when added in similar concentrations. Low concentrations of both drugs, HR-2 and native hyaluronic acid, exerted a hormesis-like effect on endotheliocyte metabolism. Cytotoxicity of the HR-2 formulation was lower than of native hyaluronic acid in both cell types. It should also be noted that no reliable proliferative effects of both drugs have been identified. The new information obtained in this study can help optimizing the use of hyaluronic acid drugs in biomedicine to achieve the best therapeutic effect and reduce undesirable consequences of its use.

Kraft Lignin Grafted with Polyvinylpyrrolidone as a Novel Microbial Carrier in Biogas Production

The objective of this study was to verify the effect of kraft lignin as a microbial carrier on biogas/methane yield. An anaerobic co-digestion test process was carried out, in which confectionery waste was used with sewage sludge. At the first stage of the study pure lignin and lignin combined with polyvinylpyrrolidone (PVP) were subjected to an extensive physicochemical analysis. Their morphology, dispersion and adsorption properties were determined. The two materials were also subjected to thermal, spectroscopic and elementary analysis. The anaerobic digestion of the two substrates was carried out with and without the addition of the carrier, under mesophilic conditions and in periodic operation. The monitoring and analysis of the two essential parameters, i.e., pH and volatile fatty acids/total alkalinity (VFA/TA) ratio, revealed that the process was stable in both tests. Microbial and biochemical analyses showed intensified proliferation of eubacteria and increased dehydrogenase activity in samples prepared with the lignin + PVP material. The cell count increased by 46% in the stuffed wafers (WAF) + sewage sludge (SS) variant with the carrier, whereas the enzyme activity increased by 43%. Cell immobilisation noticeably improved the process efficiency. The biogas production increased from 722 m3 Mg−1 VS to 850 m3 Mg−1 VS (VS – volatile solids), whereas the methane production increased from 428 m3 Mg−1 VS to 503 m3 Mg−1 VS (by about 18%). The research proved that lignin could be used as a very effective microbial carrier in anaerobic digestion (AD).

Improved growth and nutrient acquisition of wheat genotypes in phosphorus deficient soils by plant growth-promoting rhizospheric and endophytic bacteria

ABSTRACTIn this study, two bacterial strains were isolated from the rhizosphere and inside the roots of wheat (Triticum aestivum L.) plants growing in wheat land of Iran. Based on the 16s rRNA gene sequences, strains R185 and E240 were identified as Pseudomonas sp. (rhizospheric isolate) and Pseudomonas mosselii (endophytic isolate), respectively. Isolates were tested for traits that affect plant growth such as indole-3-acetic acid, siderophore, hydrogen cyanide production, and phosphate solubilization ability. Then the effect of strains on growth promotion, protein, nutrients of grains, and soil enzyme activity was investigated using a low-phosphorous soil under greenhouse conditions. Results revealed that significantly higher biomass accumulation and micronutrient assimilation were obtained in all the pots treated with bacterial strains as compared to the control. Co-inoculation of rhizospheric and endophytic bacteria improved the protein of grain by 11.3% (Marvdasht) and 9% (Roshan). Microbial inoculation had a positive effect on the concentration of P, Zn, and Fe in wheat grains. While inoculating wheat genotypes with a single rhizospheric strain increased dehydrogenase activity by 53.4%, this effect became stronger with increasing endophytic strain: up to 72% increase in soil dehydrogenase activity was observed in bacterial consortium treatment. Taken together, inoculation by rhizospheric–endophytic mix-strains with multi-plant growth-promoting traits could be a promising option to promote cereal quality.

Effect of aluminium oxide nanoparticles on the enzymatic activity on microorganisms of activated sludge

The increased production and commercial use of nanoparticles (NPs), combined with a lack of regulation regarding their disposal, may result in the unwanted introduction of NPs to wastewater. Wastewater nutrient removal depends on the metabolisms of activated sludge bacteria and their related key enzymes. Therefore, the aim of this work was to determine the effect of aluminium oxide nanoparticles concentrations on the activated sludge enzymatic activity of microorganisms. Tested nanoparticles inhibition cellular respiration in TTC method in the four highest tested concentrations. Moreover, in most samples observed increase dehydrogenase activity. In this study, nano-Al2O3 also caused a clear stimulation of the activity of hydrolytic enzymes microorganisms of activate sludge. Effects of aluminum oxide (compound in bulk forms) on enzymatic activity were different than in the case of the nano from of Al2O3.

Phosphine production in anaerobic wastewater treatment under tetracycline antibiotic pressure

The influence of tetracycline (TC) antibiotics on phosphine (PH3) production in the anaerobic wastewater treatment was studied. A lab-scale anaerobic baffled reactor with three compartments was employed to simulate this process. The reactor was operated in a TC-absence wastewater and 250μg/L TC-presence wastewater for three months after a start-up period, respectively. The responses of pH, oxidation–reduction potential (ORP), chemical oxygen demand (COD), total phosphorus (TP), enzymes activity (dehydrogenase and acid phosphatase), and microbial community were investigated to reveal the effect of TC on PH3 production. Results suggested that the dehydrogenase (DH) activity, acid phosphatase (ACP) activity and COD have positive relationship with PH3 production, while pH, ORP level and the TP in liquid phase have negative relationship with PH3 production. With prolonged TC exposure, decrease in pH and increase in DH activity are beneficial to PH3 production, while decrease in COD and ACP activity are not the limiting factors for PH3 production.