Adenine Content Research Articles

Pentachlorophenol Exposure Delays the Recovery of Colitis in Association With Altered Gut Microbiota and Purine Metabolism.

Pentachlorophenol (PCP) was used widely as preservative and biocide and has been banned due to with various harmful effects, such as carcinogenicity and teratogenicity. However, the effects of PCP on colitis induced by dextrose sodium sulfate (DSS) remain largely unknown. Serum metabolomics and gut microbiota were investigated to elucidate the underlying mechanisms. Exposure to 20 μg/L PCP aggravated DSS-induced body weight loss, colon shortening, severe histological injuries, and upregulation of TNFα, iNOS, IL-1β, and IL-6. Serum metabolomics showed that both DSS and PCP could significantly disrupted tryptophan metabolism in normal mice. Interestingly, PCP exposure intensified the disturbance in purine metabolism but not tryptophan metabolism caused by DSS. Quantitative analysis of tryptophan and metabolites further confirmed that PCP exposure significantly increased the serum contents of serotonin, adenine, guanine, guanosine, inosine monophosphate (IMP), inosine, and hypoxanthine in DSS-treated mice. The overall gut microbial community was significantly modified by PCP and DSS treatment alone. Rikenellaceae_RC9_Gut_group, Colidextribacter, and Desulfovibrio were more abundant in colitis mice following PCP exposure. Further integrative analysis of differential bacteria and purine metabolites highlighted a significant correlation between Desulfovibrio and several purine metabolites, including guanine, guanosine, hypoxanthine, IMP, and inosine. Adenosine ribonucleotides de novo biosynthesis, inosine-5'-phosphate biosynthesis I, and urate biosynthesis/inosine 5'-phosphate degradation pathways were depleted in colitis mice upon PCP treatment. Taken together, PCP exposure delayed the recovery of colitis induced by DSS in association with altered gut microbiota and serum metabolites, which were enriched in tryptophan and purine metabolism.

Integrated Application of Risk Management Techniques in Developing an Analysis Method for Traditional Chinese Medicine: A Case Study of a Percolation Solution for Xiaochaihu Capsules

Risk management should run through the entire process of method development, utilization, and maintenance. Based on the analytical quality by design (AQbD) concept, various integrated risk management techniques were used in this study to develop an analysis method for the percolation solution of Xiaochaihu capsules. During the development of the analysis method, risk assessment was conducted using an Ishikawa diagram and failure mode effects analysis, followed by method optimization using experimental design. The probability of nonconformance calculated via an exhaustive Monte Carlo method quantitatively characterized the risk magnitude of method parameter failures, leading to the establishment of a operable design region method based on risk magnitude. Validation experiments and robustness tests of the data were utilized for model refinement and initial risk review. Methodological validation of the developed method was performed, and control strategies for the analysis method were presented through a decision tree. Stability experiments demonstrated that the samples remained stable at 4 °C for 24 h. The average recovery rate fell between 98.8% and 105%, with relative standard deviations ranging from 2.73% to 4.48%. The results showed that the established analysis method exhibited robustness. This analysis method can simultaneously determine the contents of uridine, adenine, 5-hydroxymethylfurfural, and guanosine. This method can also be employed for process control during percolation. This study integrated various risk management techniques to develop and maintain the analysis method, and this approach can potentially be extended to other analytical methods.

Evolution of retrocopies in the context of HUSH silencing

Retrotransposition is one of the main factors responsible for gene duplication and thus genome evolution. However, the sequences that undergo this process are not only an excellent source of biological diversity, but in certain cases also pose a threat to the integrity of the DNA. One of the mechanisms that protects against the incorporation of mobile elements is the HUSH complex, which is responsible for silencing long, intronless, transcriptionally active transposed sequences that are rich in adenine on the sense strand. In this study, broad sets of human and porcine retrocopies were analysed with respect to the above factors, taking into account evolution of these molecules. Analysis of expression pattern, genomic structure, transcript length, and nucleotide substitution frequency showed the strong relationship between the expression level and exon length as well as the protective nature of introns. The results of the studies also showed that there is no direct correlation between the expression level and adenine content. However, protein-coding retrocopies, which have a lower adenine content, have a significantly higher expression level than the adenine-rich non-coding but expressed retrocopies. Therefore, although the mechanism of HUSH silencing may be an important part of the regulation of retrocopy expression, it is one component of a more complex molecular network that remains to be elucidated.

Molecular mechanisms behind the generation of pro-oncogenic HIV-1 matrix protein p17 variants.

HIV-1 matrix protein p17 variants (vp17s), characterized by amino acid insertions at the COOH-terminal region of the viral protein, have been recently identified and studied for their biological activity. Different from their wild-type counterpart (refp17), vp17s display a potent B cell growth and clonogenic activity. Recent data have highlighted the higher prevalence of vp17s in people living with HIV-1 (PLWH) with lymphoma compared with those without lymphoma, suggesting that vp17s may play a key role in lymphomagenesis. Molecular mechanisms involved in vp17 development are still unknown. Here we assessed the efficiency of HIV-1 Reverse Transcriptase (RT) in processing this genomic region and highlighted the existence of hot spots of mutation in Gag, at the end of the matrix protein and close to the matrix-capsid junction. This is possibly due to the presence of inverted repeats and palindromic sequences together with a high content of Adenine in the 322-342 nucleotide portion, which constrain HIV-1 RT to pause on the template. To define the recombinogenic properties of hot spots of mutation in the matrix gene, we developed plasmid vectors expressing Gag and a minimally modified Gag variant, and measured homologous recombination following cell co-nucleofection by next-generation sequencing. Data obtained allowed us to show that a wide range of recombination events occur in concomitance with the identified hot spots of mutation and that imperfect events may account for vp17s generation.

MiR156-PvSPL2 controls culm development by transcriptional repression of switchgrass CYTOKININ OXIDASE/DEHYDROGENASE4.

Culm development in grasses can be controlled by both miR156 and cytokinin. However, the crosstalk between the miR156-SPL module and the cytokinin metabolic pathway remains largely unknown. Here, we found CYTOKININ OXIDASE/DEHYDROGENASE4 (PvCKX4) plays a negative regulatory role in culm development of the bioenergy grass Panicum virgatum (switchgrass). Overexpression of PvCKX4 in switchgrass reduced the internode diameter and length without affecting tiller number. Interestingly, we also found that PvCKX4 was always upregulated in miR156 overexpressing (miR156OE) transgenic switchgrass lines. Additionally, upregulation of either miR156 or PvCKX4 in switchgrass reduced the content of isopentenyl adenine (iP) without affecting trans-zeatin (tZ) accumulation. It is consistent with the evidence that the recombinant PvCKX4 protein exhibited much higher catalytic activity against iP than tZ in vitro. Furthermore, our results showed that miR156-targeted SPL2 bound directly to the promoter of PvCKX4 to repress its expression. Thus, alleviating the SPL2-mediated transcriptional repression of PvCKX4 through miR156 overexpression resulted in a significant increase in cytokinin degradation and impaired culm development in switchgrass. On the contrary, suppressing PvCKX4 in miR156OE transgenic plants restored iP content, internode diameter, and length to wild-type levels. Most strikingly, the double transgenic lines retained the same increased tiller numbers as the miR156OE transgenic line, which yielded more biomass than the wild type. These findings indicate that the miR156-SPL module can control culm development through transcriptional repression of PvCKX4 in switchgrass, which provides a promising target for precise design of shoot architecture to yield more biomass from grasses.

Enhanced production of cordycepin under solid-state fermentation of Cordyceps militaris by using combinations of grains/substrates.

This manuscript deals with cordycepin, an interesting secondary compound produced from entomopathogenic fungus, Cordyceps. It has attracted commercial interest due to its immense pharmacological importance beneficial to human health. In this study, the contents of cordycepin and its derivatives, like adenine and adenosine, were evaluated through solid-state fermentation using combinations of various grains as substrate. Treatment with grain combination numbers 2, 7, 8, and 9 exhibited higher cordycepin content (1.621, 1.929, 1.895, and 1.996mg/g cordycepin, respectively) than control (rice). The grain combination number 7 exhibited significantly higher adenine content (700mg/g) than the control and all other combinations. Treatments with grain combination numbers 2, 5, and 7 exhibited higher adenosine content (2.719, 2.938, and 3.392mg/g, respectively); however, no significant increase in adenosine content was noted in any treatments. The biomass including fresh mycelium and fruit body was found higher in grain combination numbers 7 and 9, leading to enhanced cordycepin content. Overall, the increase in the fresh biomass significantly enhanced cordycepin accumulation. The level of cordycepin was recorded as higher than that of its derivatives, adenosine and adenine. The grain combination of rice, wheat, jowar, bajra, and sugarcane bagasse added to basal medium exhibited the highest cordycepin content and was found suitable for solid-state fermentation of Cordyceps militaris. To our understanding, the present study is the first to use combinations of cereals for the production of cordycepin from C. militaris.

Nicotinamide Riboside and Phycocyanin Oligopeptides Affect Stress Susceptibility in Chronic Corticosterone-Exposed Rats.

Nicotinamide riboside (NR) is an NAD+ precursor capable of regulating mammalian cellular metabolism. Phycocyanin oligopeptide (PC), a phytonutrient found in blue-green algae, has antioxidant and anti-inflammatory properties. This study explored the effects of NR, PC, and their combination on the telomere length as well as inflammatory and antioxidant status of rats under chronic stress conditions (CS). Forty-nine rats were allocated into seven groups: control, chronic stress (CS), CS with NR (26.44 mg/kg), a low dose of 2.64 mg/kg of PC (PC-LD), or a high dose of 26.44 mg/kg PC (PC-HD), NR + PC-LD, and NR + PC-HF. The rats were given daily corticosterone injections (40 mg/kg) to induce stress conditions, or NR and PC were orally administered for 21 days. NR and PC supplementation, particularly NR plus PC, increased the serum antioxidant enzyme activities, hepatic nicotinamide adenine (NAD+) content, and telomere length (p < 0.001 for all) compared to the CS group. The levels of serum malondialdehyde (MDA), liver interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), IL-1β, and IL-8 were reduced under the CS condition (p < 0.001). In addition, CS decreased the levels of hepatic telomere-related proteins and sirtuins (SIRT1 and 3), whereas administration of NR and PC or their combination to CS-exposed rats increased the levels of telomere-related proteins (e.g., POT1b, TRF1 and TRF2), SIRT3 and NAMPT (p < 0.05). In conclusion, NR and PC, especially their combination, can alleviate metabolic abnormalities by enhancing hepatic cytokines, SIRT3, NAMPT, and NAD+ levels in CS-exposed rats. More research is needed to further elucidate the potential health effects of the combination of NR and PC in humans.

Effects of different temperatures and diets on nutritional and bio‐functional components in the juvenile lined seahorse (Hippocampus erectus)

AbstractA two‐factorial experiment (temperature with three levels: 23°C, 25.5°C and 28°C; diet with four kinds: live Artemia sp., copepods, live Artemia sp. + copepods and frozen Neomysis awatschensis [FNA]) was carried out to evaluate the effects of different temperatures and diets on biochemistry in the juvenile lined seahorse (Hippocampus erectus) for thirty days. The juveniles (n = 1260, body height: 5.1 ± 0.48 cm, initial wet weight: 0.42 ± 0.14 g) were distributed in 36 experimental aquaria (35 individuals each). Each treatment had 3 replicates. On day 30, the seahorses were vacuum freeze‐dried at −56°C before chemical analysis. Amino acids, fatty acids, Se, Zn, nucleosides, and nucleotides were measured in the present study. The results show that temperature, diet, and their interaction significantly affected all components. The content of amino acids and fatty acids in the juveniles fed FNA at 23°C was the highest. The content of Zn in the juveniles fed FNA at 23°C, and the content of Se fed Artemia sp. + copepod at 25.5°C were the highest, respectively. The content of uracil, adenine, and thymidine in the juveniles at 23°C was significantly lower than those treatments at 25.5°C and 28°C. The levels of uracil, guanine, cytosine, uridine, and guanosine at 28°C were significantly higher than those at 23°C or 25.5°C when fed Artemia sp. + copepod. The juveniles fed Artemia sp. + copepod and Artemia sp. at 28°C has the highest comprehensive scores of nucleoside and nucleotide. In conclusion, FNA is the best feed to improve the content of amino acids, fatty acids, and Zn at 23°C.

The Influence of the Selection at the Amino Acid Level on Synonymous Codon Usage from the Viewpoint of Alternative Genetic Codes

Synonymous codon usage can be influenced by mutations and/or selection, e.g., for speed of protein translation and correct folding. However, this codon bias can also be affected by a general selection at the amino acid level due to differences in the acceptance of the loss and generation of these codons. To assess the importance of this effect, we constructed a mutation-selection model model, in which we generated almost 90,000 stationary nucleotide distributions produced by mutational processes and applied a selection based on differences in physicochemical properties of amino acids. Under these conditions, we calculated the usage of fourfold degenerated (4FD) codons and compared it with the usage characteristic of the pure mutations. We considered both the standard genetic code (SGC) and alternative genetic codes (AGCs). The analyses showed that a majority of AGCs produced a greater 4FD codon bias than the SGC. The mutations producing more thymine or adenine than guanine and cytosine increased the differences in usage. On the other hand, the mutational pressures generating a lot of cytosine or guanine with a low content of adenine and thymine decreased this bias because the nucleotide content of most 4FD codons stayed in the compositional equilibrium with these pressures. The comparison of the theoretical results with those for real protein coding sequences showed that the influence of selection at the amino acid level on the synonymous codon usage cannot be neglected. The analyses indicate that the effect of amino acid selection cannot be disregarded and that it can interfere with other selection factors influencing codon usage, especially in AT-rich genomes, in which AGCs are usually used.

Genetics of Hydrocephalus (HC)

Genetic hydrocephalus is a neurological condition in which the cerebrospinal fluid (CSF) flows with subsequent and it results in enlargement of the cerebral ventricular cavities. The common cause of the congenital hydrocephalus is the variation in the L1CAM gene, and there is the narrow passage between the third and fourth ventricles. It is suggesting that hydrocephalus is more complicated than the simple CSF , and are many factors which are associated with the genetics of hydrocephalus, the major two factors are the i) telomeres proximity ii) and the more content of Adenine and Thymine [A, T] in the human CH as compared to the other nervous disorders. It is also suggesting that genetics of hydrocephalus is a crucial birth defect, and its genetics is still not completely understood, so it is the most important clinical feature. There are about 43 mutant loci associated with the animals and human hydrocephalus. Among them 9 are associated with animal models and 1 with the human. The most important hydrocephalus gene products are the growth factors, cytokines and many cellular signal pathways in the starting stage of brain development. In this study we will aim to understand the abnormalities in brain cause by the abnormal cellular functioning, and all these cellular events results congenital hydrocephalus. All these studies show that it is the mandolin type of disease with reference to the cellular, molecular genetics, physiological and pathological studies.

Gradual effects of gradient concentrations of polystyrene nanoplastics on metabolic processes of the razor clams

With the widespread occurrence and accumulation of plastic waste in the world, plastic pollution has become a serious threat to ecosystem and ecological security, especially to estuarine and coastal areas. Understanding the impacts of changing nanoplastics concentrations on aquatic organisms living in these areas is essential for revealing the ecological effects caused by plastic pollution. In the present study, we revealed the effects of exposure to gradient concentrations (0.005, 0.05, 0.5 and 50 mg/L) of 75 nm polystyrene nanoplastics (PS-NPs) for 48 h on metabolic processes in muscle tissue of a bivalve, the razor clam Sinonovacula constricta, via metabolomic and transcriptomic analysis. Our results showed that PS-NPs caused dose-dependent adverse effects on energy reserves, membrane lipid metabolism, purine metabolism and lysosomal hydrolases. Exposure to PS-NPs reduced energy reserves, especially lipids. Membrane lipid metabolism was sensitive to PS-NPs with contents of phosphocholines (PC), phosphatidylethanolamines (PE) and phosphatidylserines (PS) increasing and degradation being inhibited in all concentrations. High concentrations of PS-NPs altered the purine metabolism via increasing contents of guanosine triphosphate (GTP) and adenine, which may be needed for DNA repair, and consuming inosine and hypoxanthine. During exposure to low concentrations of PS-NPs, lysosomal hydrolases in S. constricta, especially cathepsins, were inhibited while this influence was improved transitorily in 5 mg/L of PS-NPs. These adverse effects together impacted energy metabolism in S. constricta and disturbed energy homeostasis, which was manifested by the low levels of acetyl-CoA in high concentrations of PS-NPs. Overall, our results revealed the effects of acute exposure to gradient concentrations of PS-NPs on S. constricta, especially its metabolic process, and provide perspectives for understanding the toxicity of dynamic plastic pollution to coastal organisms and ecosystem.

Reduksi Purin pada Emping Melinjo Melalui Pre-treatment Perendaman Emping Mentah

Melinjo chips (emping as local name) has high purine content which can be related to the high uric acid level in blood that lead to joint inflamation due to the sendimentation of uric acid. The objective of this research is to prove that soaking process can reduce purine content in emping and to know the effect of the soaking process length in purine reduction. Soaking time (2, 5, and 12 hours) and emping brand (Sriti, A1 and Koki) were used as the treatments. Purine compounds such as adenine and hypoxanthine were analyzed by using High Performance Liquid Chromatography (HPLC) method with C18 column and UV detector. The three emping samples were also analyzed by using sensory evaluation to know the consumer preference toward the treated fried emping. Results obtained from this research were that soaking process can reduce both adenine and hypoxanthin content in emping. Soaking for 2 hours in water could reduce adenine content 13 – 39% and hypoxanthine content 4 – 60%. Soaking process for 2 hours on emping could reduce up to 50% of total purine base content in A1 brand, however, soaking time was not directly proportional to the decrease in purine levels. Purine content after 5 and 12 hours soaking tend to be fluctuative. Emping samples that were soaked in the water have a decrease in preference by the panelists either in color, aroma, taste, texture or in overall, but still accepted by panelists.

Application of Gamma Rays Irradiation to Reduce Purine Base of Adenine and Hypoxanthine Content on Melinjo Chips (Gtnetum Gnemon L)

Background : Melinjo (Gnetum gnemon L) chips known as popular snack among Indonesian. This kind of chips often associated with high uric acid level in the blood that is influenced by high level of purine. Therefore, an additional process is required to reduce purine content. It can increase acceptability and safety to consumer particularly for people with a previous history of hyperuricemia or gout. Objective : To determine and analyze the effect gamma ray irradiation on purin content of adenine and hypoxanthine including quuality properties of melinjo chips. Method : Research design apllied completely randomized design. Level of purin adenina and hypoxanthine analyzed using HPLC-UV. Chemical properties obtained using proximate analysis. In addition, hedonic sensory analysis test was applied in order to determine acceptability of the product. Result: Gamma ray irradiation conclusively can reduced purine base of adenine and hypoxanthine level approximately up to 17,82%. The higher dose of ray, the lower the purine level. Gamma ray effect significantly on the anorganic elements, fat, protein, and carbohydrate contents of the melinjo chips, along with its texture, appeareance and flavor. Conclusion : Irradiation reduced significantly purine base of adenine and hypoxanthine, nutritional content and organoleptic properties of melinjo chips. Keyword : Adenine; Gamma Ray; Gnetum gnemon L; Hypoxanthine; Irradiation

Anemoside B4 Protects Rat Kidney from Adenine-Induced Injury by Attenuating Inflammation and Fibrosis and Enhancing Podocin and Nephrin Expression.

Anemoside B4 (B4) isolated from Radix Pulsatilla has anti-inflammatory activities in the colon and antitumor effects. However, its role in the prevention and treatment of kidney injury has not been reported. Here, we reported the effects of B4 on chronic kidney injury (CKI) and studied its related mechanism based on an adenine-induced kidney injury model in rats. The results showed that serum BUN (blood urea nitrogen), Crea (creatinine), and urinary proteins increased significantly after oral administration of adenine. Meanwhile, the adenine contents in both renal tissue and urine increased markedly compared with those of normal rats. Moreover, IL-1β, IL-6, TNFα, and NFκB expression was upregulated in the kidney. Simultaneously, the expression of NLRP3 (the nucleotide-binding and oligomerization domain–like receptor, leucine-rich repeat and pyrin domain–containing 3) in the inflammasome, which consists of Caspase 1, ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain), and IL-18, was significantly upregulated. B4 could significantly decrease BUN and Crea; reduce urinary proteins in rats; suppress the expression of IL-6, IL-1β, NFκB, NLRP3, Caspase 1, ASC, and IL-18; and increase urinary adenine contents and promote its excretion. In addition, B4 also upregulated the expression of podocin and nephrin, two major podocyte proteins, and reduced the fiber collagen in the renal interstitial, suggesting that B4 could protect the glomerular matrix from adenine injury in addition to its anti-inflammatory effects. The results of this study show new perspective of B4 as a potential drug against adenine-induced renal injury.

Effect of Tetrameric Base-Pair Context on the Sequence-Dependent Configurations of DNA Minicircles

The biophysical characteristics of various DNA configurations, ranging from changes in localized base-pair twisting to global writhe, are known to be influenced by nucleotide sequence and composition. Decades worth of experimental findings have shown how regions of high adenine content exhibit high degrees of bending or how pyrimidine-purine dimers exhibit a high twist/low twist polymorphism, examples critical in protein interactions and genetic expression. Calculations and subsequent modeling in the past have been limited to dimeric base pair steps but the recent influx of high-resolution structural data has shown these steps to be influenced by both their 3′ and 5′ nearest neighbors, such as conformational differences of the internal AA dimers in the context of A-AA-A and A-AA-C tetramers. The growing database of high-resolution nucleic acid-containing structures can be harnessed to generate intrinsic rigid-body parameters and elastic constants of successive base pairs in all tetrameric contexts. Optimizing the elastic energy of DNA minicircles at the dinucleotide level has been used to determine the effects of sequence on global shape and elasticity. These optimizations make use of an array of intrinsic dimer models ranging from a simple linear model, a curved three-state model, or one of higher complexity with rigid-body parameters and elastic constants unique to each dimer, as well as impose spatial constraints to mimic behavior observed in protein-DNA interactions. These models have been further refined to include nearest neighbor interactions. Elastic energy minimization calculations were used on multiple circular configurations with sequences of high A⋅T content. Comparative analysis between optimization results are useful in exploring how purine and pyrimidine nucleotides before and after a dinucleotide sequence may affect polymer shape and elasticity.

Identification and molecular analysis of a lncRNA-HOTAIR transcript from secondary hair follicle of cashmere goat reveal integrated regulatory network with the expression regulated potentially by its promoter methylation

The HOTAIR transcript is transcribed from the antisense strand within the HOXC gene cluster, and it is thought to play a role in regulating the inductive capacity of dermal papilla cells during the reconstruction of hair-follicle. In the current investigation, we firstly isolated and characterized a lncRNA-HOTAIR transcript from the secondary hair follicle of cashmere goat. Also, we analyzed its transcriptional pattern and methylation level of HOTAIR gene promoter in secondary hair follicle of cashmere goat during anagen and telogen stages. Nucleotide composition analysis indicated that the contents of Adenine (A) and Thymine (T) are higher than that of Guanine (G) and Cytosine (C) in lncRNA-HOTAIR transcript of cashmere goat with the highest frequency distribution of AG nucleotide pair (8.06%). The regulatory network analysis showed a directly or indirectly complex regulatory relationships between lncRNA-HOTAIR of cashmere goat and its potential target molecules: miRNAs, mRNAs and proteins. Also, we showed that lncRNA-HOTAIR was properly transcribed at both anagen and telogen stages of secondary hair follicle of cashmere goat with the anagen being significantly higher than telogen in its expression, which suggest that lncRNA-HOTAIR transcript might be involved in the reconstruction of secondary hair follicle with the formation and growth of cashmere fiber. Taken together with methylation analysis of HOTAIR gene promoter, our data suggest that the promoter methylation of HOTAIR gene most likely is involved in its transcriptional suppression in secondary hair follicle of cashmere goat.

Fabrication of Cu−CeO2 Coated Multiwall Carbon Nanotube Composite Electrode for Simultaneous Determination of Guanine and Adenine

AbstractA copper nano particles and cerium (IV) oxide modified carbon nanotube based composite on glassy carbon electrode (Cu−CeO2/MWCNT/GCE) was fabricated for simultaneous determination of guanine and adenine. The surface morphology, chemistry and conductance of the prepared electrodes were characterized by scanning electron microscopy (SEM), energy dispersion X‐ray (EDX), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The Cu−CeO2/MWCNT/GCE improved electrochemical behaviour of guanine and adenine compared to other electrodes. The modified electrode was also used for individual and simultaneous determination of guanine and adenine. Under optimized conditions, the calibration curves were obtained linearly in the range of 0.20 to 6.00 μM for the guanine and 0.10 to 8.0 μM for the adenine by differential pulse voltammetry. The limits of detection of guanine and adenine were calculated as 0.128 and 0.062 μM, respectively. Interferences studies were also performed in the presence of inorganic and organic compounds. Moreover, the determination of guanine and adenine contents were carried out in a calf thymus DNA sample by the developed method with satisfactory results.

ACCUMULATION OF PHYTOHORMONES BY SOIL BACTERIA AZOTOBACTER VINELANDII AND BACILLUS SUBTILIS UNDER THE INFLUENCE OF NANOMATERIALS

Azotobacter vinelandii IMV B-7076 was shown to be capable of biosynthesis and accumulation of various biologically active substances, including high amounts of 3-indoleacetic acid (IAA) in free and bound forms, in the cultural medium. Cultivation of these bacteria with vermiculite particles had increased accumulation of abscisic acid (ABA) in 2.3 times compared to the control. Addition of silica dioxide nanoparticles to the nutrient medium had resulted in higher cytokinin content. Thus, the detected amount of zeatin was 2.4 times higher; zeatin-riboside – higher in 3.6 times; while the content of zeatin-glucoside had a slight increase by 3%. High amounts of cytokinins, 3-indoleacetic and abscisic acids were also detected in the cultural medium of Bacillus subtilis IMV B-7023. Bacteria cultivation in the presence of vermiculite particles in nutrient medium had stimulated an increase of isopentyl adenine content in 4.0 times compared to control. Substantial (in 4.5 times) increase of 3-indoleacetic acid synthesis compared to control was detected. Addition of nanoparticles to the nutrient medium of Bacillus subtilis IMV B-7023 had also promoted synthesis of the abscisic acid in 1.7 times compared to control.

Determination of the Main Nucleosides and Nucleobases in Natural and Cultured Ophiocordyceps xuefengensis.

Ophiocordyceps xuefengensis, a recently described species of Ophiocordyceps that is associated with the larvae of Phassus nodus (Hepialidae) in the living root or trunk of the medicinal plant Clerodendrum cyrtophyllum, is the largest known Cordyceps species and is recognized as a desirable alternative for natural Ophiocordyceps sinensis. This study investigated the main nucleosides and nucleobases in natural and cultured Ophiocordyceps xuefengensis. The contents of the nucleosides and nucleobases in the natural and cultured samples were determined by reverse phase HPLC. The highest concentration of adenosine was found in the natural fruit body and the cultured stroma, with almost no adenosine in the cadaver of Phassus nodus. The contents of adenine, guanosine, uridine and uracil in the cultured mycelium were significantly higher than those in the natural sample. Inosine was only detected in the natural samples. Thymidine and 2-deoxyadenosine were only found in the cadaver of Phassus nodus. Cordycepin was not detected in the five samples examined. These results suggested that the cultured mycelium and cultured stroma of Ophiocordyceps xuefengensis might be a promising substitute for natural O. xuefengensis.

New MWCNT-Fe3O4@PDA-Ag nanocomposite as a novel sensing element of an electrochemical sensor for determination of guanine and adenine contents of DNA

Herein, we report a facile approach to prepare an MWCNT-Fe3O4@PDA-Ag nanocomposite that can act toward purine bases. The nanocomposite was characterized with Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The characterization results showed that Ag nanoparticles were well anchored onto the polydopamine (PDA) cover of the MWCNT-Fe3O4@PDA nanocomposite. The produced nanocomposite was successfully incorporated as the heart of a sensing element to design a novel electrochemical sensor for individual or simultaneous determination of guanine (G) and adenine (A). The sensor showed an excellent electrocatalytical function toward determination of G and A. The oxidation peak currents were linear over the concentration ranges of 8–130 and 10–120μM for G and A, respectively. The lower detection limits of the sensor were estimated to be 1.47μM for G and 5.66μM for A. The MWCNT-Fe3O4@PDA-Ag nanocomposite based sensor was successfully applied to detect G and A in fish sperm DNA sample.