Increased expression of ORMDL3 in allergic asthma: a case control and in vitro study.

BACKGROUND: Asthma is the most frequent chronic disease in children. One of the most replicated genetic findings in childhood asthma is the ORMDL3 gene confirmed in several GWA studies in several pediatric populations. OBJECTIVES: The purpose of this study was to analyze ORMDL3 variants and expression in childhood asthma in the Polish population. METHODS: In the study we included 416 subject, 223 asthmatic children and 193 healthy control subjects. The analysis of two SNPs (rs3744246 and rs8076131) was performed using genotyping with TaqMan probes. The methylation of the ORMDL3 promoter was examined with Methylation Sensitive HRM (MS-HRM), covering 9 CpG sites. The expression of ORMDL3 was analyzed in PBMCs from pediatric patients diagnosed with allergic asthma and primary human bronchial epithelial cells derived from healthy subjects treated with IL-13, IL-4, or co-treatment with both cytokines to model allergic airway inflammation. RESULTS: We found that ORMDL3 expression was increased in allergic asthma both in PBMCs from asthmatic patients as well as in human bronchial epithelial cells stimulated with the current cytokines. We did not observe significant differences between cases and controls either in the genotype distribution of analyzed SNPs (rs3744246 and rs8076131) nor in the level of promoter methylation. CONCLUSIONS: Increased ORMDL3 expression is associated with pediatric allergic asthma and upregulated in the airways upon Th2-cytokines stimulation, but further functional studies are required to fully understand its role in this disease.

Zinc Finger Proteins in Head and Neck Squamous Cell Carcinomas: ZNF540 May Serve as a Biomarker.

Head and neck squamous cell carcinoma (HNSCC) is one of the ten most common cancers. Most cancer cases originate from alcohol and tobacco consumption. However, studies have demonstrated that human papillomavirus (HPV) infection, particularly HPV-16, may also significantly influence disease progression. The KRAB-ZNF family of genes is involved in epigenetic suppression, and its involvement in carcinogenesis is the subject of extensive studies. The available literature data demonstrate that they may play different roles, both as tumor suppressors and oncogenes. In this study, six ZNF genes, ZFP28, ZNF132, ZNF418, ZNF426, ZNF540, and ZNF880, were tested using several in silico approaches based on the TCGA and GEO datasets. Our analyses indicate that the expression of the analyzed ZNFs was significantly downregulated in tumor tissues and depended on tumor localization. The expression levels of ZNFs differed between HPV-positive vs. HPV-negative patients depending on the clinical-pathological parameters. More specifically, the patients with higher levels of ZNF418 and ZNF540 showed better survival rates than those with a lower expression. In addition, the level of ZNF540 expression in HPV-positive (HPV(+)) patients was higher than in HPV-negative (HPV(-)) patients (p < 0.0001) and was associated with better overall survival (OS). In conclusion, we demonstrate that ZNF540 expression highly correlates with HPV infection, which renders ZNF540 a potential biomarker for HNSCC prognosis and treatment.

Differential expression profile between amygdala and blood during chronic lithium treatment in a rat model of depression - a pilot study.

Lithium is a mood stabilizer widely used in the pharmacotherapy of bipolar disorder and treatment­resistant depression. Taking into account dysregulated inflammatory activity in depression and the immunomodulatory role of lithium, we hypothesized that genes associated with inflammatory responses may be potential biomarkers of lithium action. We aimed to compare gene expression changes between the brain and the periphery after chronic lithium administration in an animal model of depression. Depressive behavior was induced by chronic mild stress protocol for 4 weeks. After 2 weeks, rats started to receive lithium (study group) or water (reference group). The control group were rats not exposed to stress. Amygdala, hippocampus, frontal cortex and peripheral blood were analyzed using whole transcriptome expression microarrays. Changes were confirmed with qPCR and ELISA assay. After 2 weeks of lithium administration, we observed significant changes in gene expression between amygdala and peripheral blood. Logistic regression analysis determined Alox15 expression as a predictor of lithium status, as its expression was tissue­specific and increased in amygdala and decreased in blood. Analysis of serum ALOX15 protein revealed its upregulation after two­week lithium administration. Our study suggests that lithium may have therapeutic potential in depressive behaviors. These results indicate immunomodulatory effect of lithium and that Alox15 may be a new potential marker of chronic lithium treatment.

Allergic inflammation in lungs and nasal epithelium of rat model is regulated by tissue-specific miRNA expression.

INTRODUCTION: Atopic asthma and allergic rhinitis are common chronic inflammatory diseases affecting lower airways and nasal mucosa, respectively. Several reports demonstrated frequent co-occurrence of these two diseases, however, the exact molecular mechanism has not been described. The present study aimed to investigate if small non-coding RNA might be responsible for the co-occurrence of asthma and allergic rhinitis in an animal model of allergic airway inflammation. MATERIALS AND METHODS: As an in vivo model of allergic airway inflammation, we used Brown Norway rats exposed intranasally to house dust mite (HDM). Histological analysis, total IgE concentration, eosinophil counts and iNOS gene expression were determined to confirm inflammatory changes. Small RNA sequencing in the lung tissue and nasal epithelium was performed with TruSeq Small RNA Library Preparation Kit and analyzed using the BaseSpace tool. Validation of sequencing results was performed using qPCR. To assess the functional role of hsa-miR-223-3p, we transfected normal human bronchial epithelial (NHBE) cells with specific LNA-inhibitor and measured phosphorylated protein level of NF-kB with ELISA. Expression analysis of NF-kB pathway-related genes was performed using qPCR with SYBR Green and analyzed in DataAssist v3.01. Statistical analysis were done with STATISTICA version 13. RESULTS: We found 9 miRNA genes differentially expressed in the lungs of allergic rats. In nasal epithelium, only rno-miR-184 was upregulated in animals exposed to HDM. Validation with qPCR confirmed increased expression only for rno-miR-223-3p in the lungs from allergic rats. The expression of this miRNA was also increased in normal bronchial epithelial ALI cell culture stimulated with IL-13, but not in cells cultured in monolayer due to the low mRNA level of IL13RA1 and IL13RA2. Transfecting NHBE cells with hsa-miR-223-3p inhibitor increased the amount of phosphorylated NF-kB protein level and expression of MUC5AC, CCL24 and TSLP genes. CONCLUSIONS: These findings suggest that miRNAs that regulate allergic inflammation in the lungs and nasal epithelium are specific for upper and lower airways. Furthermore, our study provides new insight on the role of hsa-miR-223-3p, that via targeting NF-kB signaling pathway, regulates the expression of MUC5AC, CCL24 and TSLP. Taken together, our study suggests that miR-223-3p is a regulator of allergic inflammation and could potentially be used to develop novel and targeted therapy for asthma.

Nitric Oxide Synthase 2 Promoter Polymorphism Is a Risk Factor for Allergic Asthma in Children.

Background and Objectives: In paediatric population, atopic asthma is associated with increased eosinophil counts in patients, that correlate with the airway inflammation measured by the concentration of nitric oxide in exhaled air (FeNO). As the FeNO level is a biomarker of atopic asthma, we assumed that polymorphisms in nitric synthases genes may represent a risk factor for asthma development. The purpose of this study was to analyse the association of NOS genetic variants with childhood asthma in the Polish population. Materials and methods: In study we included 443 children-220 patients diagnosed with atopic asthma and 223 healthy control subjects. We have genotyped 4 single nucleotide polymorphisms (SNP) from 3 genes involved in the nitric oxide synthesis (NOS1, NOS2 and NOS3). All analyses were performed using polymerase chain reaction with restriction fragments length polymorphism (PCR-RFLP). Results: We observed significant differences between cases and controls in SNP rs10459953 in NOS2 gene, considering both genotypes (p = 0.001) and alleles (p = 0.0006). The other analyzed polymorphisms did not show association with disease. Conclusions: According to our results, 5'UTR variant within NOS2 isoform may have an impact of asthma susceptibility in the population of Polish children. Further functional studies are required to understand the role of iNOS polymorphism in NOS2 translation and to consider it as a novel risk factor in childhood asthma. The next step would be to apply this knowledge to improve diagnosis and develop novel personalized asthma therapies.

Local Duplication of TIR-NBS-LRR Gene Marks Clubroot Resistance in Brassica napus cv. Tosca.

Clubroot, caused by Plasmodiophora brassicae infection, is a disease of growing importance in cruciferous crops, including oilseed rape (Brassica napus). The affected plants exhibit prominent galling of the roots that impairs their capacity for water and nutrient uptake, which leads to growth retardation, wilting, premature ripening, or death. Due to the scarcity of effective means of protection against the pathogen, breeding of resistant varieties remains a crucial component of disease control measures. The key aspect of the breeding process is the identification of genetic factors associated with variable response to the pathogen exposure. Although numerous clubroot resistance loci have been described in Brassica crops, continuous updates on the sources of resistance are necessary. Many of the resistance genes are pathotype-specific, moreover, resistance breakdowns have been reported. In this study, we characterize the clubroot resistance locus in the winter oilseed rape cultivar "Tosca." In a series of greenhouse experiments, we evaluate the disease severity of P. brassicae-challenged "Tosca"-derived population of doubled haploids, which we genotype with Brassica 60 K array and a selection of SSR/SCAR markers. We then construct a genetic map and narrow down the resistance locus to the 0.4 cM fragment on the A03 chromosome, corresponding to the region previously described as Crr3. Using Oxford Nanopore long-read genome resequencing and RNA-seq we review the composition of the locus and describe a duplication of TIR-NBS-LRR gene. Further, we explore the transcriptomic differences of the local genes between the clubroot resistant and susceptible, inoculated and control DH lines. We conclude that the duplicated TNL gene is a promising candidate for the resistance factor. This study provides valuable resources for clubroot resistance breeding programs and lays a foundation for further functional studies on clubroot resistance.

Drainage ditches enhance forest succession in a raised bog but do not affect the spatial pattern of tree encroachment.

The study was conducted in the raised bog Kusowo (Baltic region, West Pomerania, Poland). Along a transect line crossing two open mires affected by forest succession we analysed tree age distribution. One of those mires had been drained in the past years and still retained some open ditches, while the other one was located far from the ditches. Every 10 meters along the transect line one tree was drilled at the root collar in order to determine its age. We also conducted phytosociological analyses and short-term water level measurements in the sample plots. We expected faster tree encroachment in the undisturbed part of the open mire. The results showed, that there were no significant differences in water table level and in soil moisture indicator values between the formerly drained and undisturbed open mire. There were also no statistically significant differences in tree encroachment between the disturbed and undisturbed mires. Location and the age distribution of the trees suggest that changes in the tree growth conditions cannot be directly explained by the general decreasing of water level in the bog, although periods following drainage works were associated with more numerous establishment of young trees, in the drained part of the bog as well as in the part not directly affected by drainage ditches.

Transcriptome Changes in Three Brain Regions during Chronic Lithium Administration in the Rat Models of Mania and Depression.

Lithium has been the most important mood stabilizer used for the treatment of bipolar disorder and prophylaxis of manic and depressive episodes. Despite long use in clinical practice, the exact molecular mechanisms of lithium are still not well identified. Previous experimental studies produced inconsistent results due to different duration of lithium treatment and using animals without manic-like or depressive-like symptoms. Therefore, we aimed to analyze the gene expression profile in three brain regions (amygdala, frontal cortex and hippocampus) in the rat model of mania and depression during chronic lithium administration (2 and 4 weeks). Behavioral changes were verified by the forced swim test, open field test and elevated maze test. After the experiment, nucleic acid was extracted from the frontal cortex, hippocampus and amygdala. Gene expression profile was done using SurePrint G3 Rat Gene Expression whole transcriptome microarrays. Data were analyzed using Gene Spring 14.9 software. We found that chronic lithium treatment significantly influenced gene expression profile in both mania and depression models. In manic rats, chronic lithium treatment significantly influenced the expression of the genes enriched in olfactory and taste transduction pathway and long non-coding RNAs in all three brain regions. We report here for the first time that genes regulating olfactory and taste receptor pathways and long non-coding RNAs may be targeted by chronic lithium treatment in the animal model of mania.

Allergic Inflammation Alters microRNA Expression Profile in Adipose Tissue in the Rat.

Adipose tissue is a major source of circulating exosomal microRNAs (miRNAs) that are modulators of the immune response in various types of tissues and organs, including airways. Still, no evidence exists if allergic airway inflammation may affect fat tissue inflammation via alterations in the miRNA expression profile. Therefore, we investigated the miRNA expression profile in the adipose tissue upon induced allergic inflammation in the airways in the rat. Brown Norway rats were chronically sensitized to house dust mite extract for seven weeks. Body composition was performed using MiniSpec Plus. The eosinophil count and the total IgE level were determined to confirm the induction of allergic inflammation. MiRNA expression profiling was done using the next-generation sequencing with validation by qPCR. We found that allergic airway inflammation significantly increased fat in adipose tissue, glucose concentration, and the gene expression of adipose tissue-derived proinflammatory peptides (leptin, TNFα). In miRNA-seq analysis, we showed significant differences in the expression of 36 mature miRNAs, three precursors, and two miRNA families in adipose tissue of allergic rats. Two miRNAs-miRNA-151-5p and miRNA-423-3p-showed significantly increased expression in qPCR in adipose tissue and lungs of sensitized animals. Allergic airway inflammation affects fat tissue and alters miRNA expression profile in adipose tissue in the rat.

Association of circadian clock TIMELESS variants and expression with asthma risk in children.

INTRODUCTION: Bronchial asthma is a chronic respiratory disease characterized by airway inflammation, allergen-induced hypersensitivity and dyspnea. Most asthmatic patients demonstrate oscillations of disease symptoms within 24 hours regulated by circadian clock genes. We hypothesized that these genes may be regulators of childhood asthma risk. OBJECTIVES: The aim was to investigate whether single-nucleotide polymorphisms (SNPs) in the circadian clock genes are associated with childhood asthma risk. We also aimed to analyze the mRNA level of clock genes in the blood of asthmatic children and NHBE cells stimulated with IL-13. MATERIALS AND METHODS: Peripheral blood was collected from 165 asthmatic and 138 healthy Polish children. NHBE cells were culture at the air-liquid interface (ALI) with IL-13 as an in vitro model of allergic inflammation. Using TaqMan probes, we genotyped 32 SNPs in: CLOCK, BMAL1, PER3 and TIMELESS. Expression analysis for TIMELESS was performed using real-time PCR with SYBR Green. For haplotype and genotype statistical analysis we used Haploview 4.2 and STATISTICA version 12, respectively. Gene expression analysis was performed in DataAssist v3.01. RESULTS: We found that three polymorphisms in TIMELESS (rs2291739, rs10876890, rs11171856) and two haplotypes (TTTT and CTAC) were associated with asthma risk. We also found significantly decreased expression of TIMELESS in the blood of asthmatic children as compared to the healthy children (P = 0.0289) and in NHBE cells stimulated with IL-13 (P = 0.0302). CONCLUSIONS: In our study, we showed for the first time that TIMELESS variants and expression may be associated with childhood asthma.

When science goes viral: The research response during three months of the COVID-19 outbreak.

Here we present the results of a bibliometric survey of peer-reviewed and pre-print papers published in the English language on issues related to COVID-19 within the first three months since a cluster of a severe acute respiratory disease of unknown etiology was officially confirmed by the Chinese Center for Disease Control and Prevention on 31 December 2019. A systematic search using PubMed/Medline and Scopus databases and preprint servers was performed. The articles were classified according to their type, subject and country of origin. Up to 31 March 2020, a total of 2062 papers published in 578 peer-reviewed journals and 1425 preprints posted mostly on medRxiv (55.4 %), were identified. The mean number of published journal papers and preprints per day in the considered period was 27 and 12, respectively, and reached a maximum of 51 and 46 per day in March, respectively. The identified articles, journal papers and preprints, mostly covered the epidemiology of COVID-19 (35.7 %), clinical aspects of infection (21.0 %), preventative measures (12.8 %), treatment options (12.5 %), diagnostics (12.2 %), mathematical modeling of disease transmission and mitigation (9.6 %), and molecular biology and pathogenesis of SARS-CoV-2 (8.7 %). The majority of the journal papers were commentaries (38.5 %), reviews (33.6 %) and original research (21.3 %), while preprints predominantly presented original results (89.8 %). Chinese scientists contributed the highest share of original research and were responsible for 32.9 % journal papers and 43.9 % preprints published in the considered period. A high number of contributions was also seen from the United States, the United Kingdom, and Italy. The benefits and potential risks of such a massive publication output are discussed. The scientific response seen during the first 3 months of the COVID-19 outbreak is a demonstration of the capabilities of modern science to react rapidly to emerging global health threats by providing and discussing the essential information for understanding the etiological factor, its spread, preventative measures, and mitigation strategies.

Marker assisted selection of new high oleic and low linolenic winter oilseed rape (Brassica napus L.) inbred lines revealing good agricultural value.

Development of oilseed rape (Brassica napus L.) breeding lines producing oil characterized by high oleic and low linolenic acid content is an important goal of rapeseed breeding programs worldwide. Such kind of oil is ideal for deep frying and can also be used as a raw material for biodiesel production. By performing chemical mutagenesis using ethyl methanesulfonate, we obtained mutant winter rapeseed breeding lines that can produce oil with a high content of oleic acid (C18:1, more than 75%) and a low content of linolenic acid (C18:3, less than 3%). However, the mutant lines revealed low agricultural value as they were characterized by low seed yield, low wintering, and high content of glucosinolates in seed meal. The aim of this work was to improve the mutant lines and develop high-oleic and low-linolenic recombinants exhibiting both good oil quality and high agronomic value. The plant materials used in this study included high-oleic and low-linolenic mutant breeding lines and high-yielding domestic canola-type breeding lines of good agricultural value with high oleic acid content and extremely low glucosinolates content. Field trials were conducted in four environments, in a randomized complete block design. Phenotyping was performed for wintering, yield of seed and oil, and seed quality traits. Genotype × environment interaction was investigated with respect to the content of C18:1 and C18:3 acids in seed oil. Genotyping was done for the selection of homozygous high oleic and low linolenic lines using allele-specific CAPS markers and SNaPshot assay, respectively. Finally, new high oleic and low linolenic winter rapeseed recombinant lines were obtained for use as a starting material for the development of new varieties that may be of high value on the oil crop market.

Neuroinflammatory Gene Expression Pattern Is Similar between Allergic Rhinitis and Atopic Dermatitis but Distinct from Atopic Asthma.

METHODS: In the study, we included 86 children diagnosed with atopic asthma (n = 25), allergic rhinitis (n = 20), and atopic dermatitis (n = 20) and healthy control subjects (n = 21) of Caucasian origin from the Polish population. The blood leukocyte expression of 31 genes involved in neuroinflammatory response (neurotrophins, their receptors, neuropeptides, and histamine signaling pathway) was analysed using TaqMan low-density arrays. The relative expression of selected proteins from plasma was done using TaqMan Protein Assays. Statistical analysis was done using Statistica. RESULTS: Blood expression of 31 genes related to neuroimmune interactions showed significant increase in both allergic diseases, allergic rhinitis and atopic dermatitis, in comparison to the control group. We found 12 genes significantly increased in allergic rhinitis and 9 genes in which the expression was elevated in atopic dermatitis. Moreover, 9 genes with changed expression in atopic dermatitis overlapped with those in allergic rhinitis. Atopic asthma showed 5 genes with altered expression. The peripheral expression of neuroinflammatory genes in the human study was verified in target tissues (nasal epithelium and skin) in a rat model of allergic inflammation. CONCLUSIONS: A common pattern of neuroinflammatory gene expression between allergic rhinitis and atopic dermatitis may reflect similar changes in sensory nerve function during chronic allergic inflammation.

Lipophilicity Determination of Antifungal Isoxazolo[3,4-b]pyridin-3(1H)-ones and Their N1-Substituted Derivatives with Chromatographic and Computational Methods.

The lipophilicity of a molecule is a well-recognized as a crucial physicochemical factor that conditions the biological activity of a drug candidate. This study was aimed to evaluate the lipophilicity of isoxazolo[3,4-b]pyridine-3(1H)-ones and their N1-substituted derivatives, which demonstrated pronounced antifungal activities. Several methods, including reversed-phase thin layer chromatography (RP-TLC), reversed phase high-performance liquid chromatography (RP-HPLC), and micellar electrokinetic chromatography (MEKC), were employed. Furthermore, the calculated logP values were estimated using various freely and commercially available software packages and online platforms, as well as density functional theory computations (DFT). Similarities and dissimilarities between the determined lipophilicity indices were assessed using several chemometric approaches. Principal component analysis (PCA) indicated that other features beside lipophilicity affect antifungal activities of the investigated derivatives. Quantitative-structure-retention-relationship (QSRR) analysis by means of genetic algorithm-partial least squares (GA-PLS)-was implemented to rationalize the link between the physicochemical descriptors and lipophilicity. Among the studied compounds, structure 16 should be considered as the best starting structure for further studies, since it demonstrated the lowest lipophilic character within the series while retaining biological activity. Sum of ranking differences (SRD) analysis indicated that the chromatographic approach, regardless of the technique employed, should be considered as the best approach for lipophilicity assessment of isoxazolones.

Application of reversed-phase thin layer chromatography and QSRR modelling for prediction of protein binding of selected ß-blockers.

Chromatographic properties of sixteen ß-blockers were studied using planar chromatography. The aim of presented study was to investigate influence of different organic solvents (acetonitrile, methanol, dioxin and tetrahydrofurane) on ß-blockers' retention on C18 bonded silica gel stationary phase. Group of sixteen, diverse in terms of structure, beta blockers was used as a model set. The main goal of this study was to compare chromatographically estimated lipophilicity parameters with values obtained with the use of computational methods. Furthermore, in order to understand molecular mechanisms of retention better, quantitative structure-retention relationships (QSRR) analysis was performed. The next step was focused on application of chromatographically obtained lipophilicity parameters for prediction of protein binding (PB), based on quantitative retention-activity relationships (QRAR) approach. The obtained results showed that reversed-phase thin layer chromatography (RP-TLC), especially with tetrafydrofurane used as an organic modifier of mobile phase, is a useful tool for lipophilicity estimation, as well as for prediction of ß-blockers' biological properties. The QRAR model included C0 parameters for tetrahydrofuran-water as a mobile phase, as well as maximal projection area, and can be easily applied for prediction of systematically synthesized ß-blockers structures' PB.

Individualization of treatment with gentamicin in neonates based on drug concentration in the blood serum.

OBJECTIVE: Aim: To evaluate how useful it is to make measurements of gentamicin concentrations in newborns' blood in order to optimize antibiotic therapy. PATIENTS AND METHODS: Material and methods: 73 newborns empirically treated with gentamicin, in doses consistent with the Neofax® guidelines. There were 152 measurements of maximum and minimum serum gentamicin concentrations. Samples were determined based on the chemiluminescence technique on the Siemens Advia Centaur analyzer. The concentrations of gentamicin that were measured were compared with various therapeutic ranges used in the literature. RESULTS: Results: According to the standards adopted in the University Hospital in Wroclaw, the maximum concentration was reached in 38.16% of all the children, while the minimum in 26.32%. In other children the concentrations were below or above the therapeutic range. According to the Neofax® guidelines, the intended maximum concentration was observed in 71.05% of the newborns, and the minimum in 32.89%. The minimum concentration of <2 mg/L was found in 93.42% of the newborns, while >2 mg/L was determined in 33.33%, despite a 48-hour dosing interval. These were premature babies (<28th week of gestational age) and 55.56% of them reached a maximum concentration of 5-12 mg/L. There was no significant correlation between maximum or minimum concentration and gestational age or body weight. CONCLUSION: Conclusions: 1. The dosage of gentamicin in newborns according to the Neofax® recommendations does not ensure achieving the intended serum antibiotic concentrations. 2. In order to optimize gentamicin therapy in newborns it is necessary to individualize the dose based on measurements of drug concentrations in the blood and pharmacokinetic calculations.

Are the short cationic lipopeptides bacterial membrane disruptors? Structure-Activity Relationship and molecular dynamic evaluation.

Short cationic lipopeptides are amphiphilic molecules that exhibit antimicrobial activity mainly against Gram-positives. These compounds bind to bacterial membranes and disrupt their integrity. Here we examine the structure-activity relation (SAR) of lysine-based lipopeptides, with a prospect to rationally design more active compounds. The presented study aims to explain how antimicrobial activity of lipopeptides is affected by the charge of lipopeptide headgroup and the length of lipopeptide acyl chain. The obtained SAR models suggest that the lipophilicity of short synthetic cationic lipopeptides is the major factor that determines their antimicrobial activities. In order to link the differences in antimicrobial activity to the mechanism of action of lipopeptides containing one and two hydrophobic chains, we additionally performed molecular dynamic (MD) simulations. By using combined coarse-grained and all-atom simulations we also show that these compounds neither affect the organization of the membrane lipids nor aggregate to form separate phases. These results, along with the onset of antimicrobial activity of lipopeptides well below the critical micelle concentration (CMC), indicate that lipopeptides do not act in a simple detergent-like manner.

Characterization of antimicrobial and hemolytic properties of short synthetic cationic lipopeptides based on QSAR/QSTR approach.

In this study, we investigated the influence of molecular descriptors of cationic lipopeptides on their antimicrobial activity and hemolytic properties. The quantitative structure-activity relationship and quantitative structure-property relationship models were constructed. The antimicrobial, hemolytic and retention data were used as dependent variable and structural parameters as the independent ones. The obtained results suggest that the chromatographic indexes can be employed for prediction of antibacterial activity and that lipopeptides present nonspecific interaction between erythrocytes and bacterial membranes.

The comparative study of micellar TLC and RP-TLC as potential tools for lipophilicity assessment based on QSRR approach.

Lipophilicity of compound is well known as vital physicochemical property of a molecule, which determines its biological activity. Nonetheless, the assessment of a lipophilicity is still problematic and focuses attention of scientists. Although, the shake-flask method is still considered as a gold standard for experimental determination of lipophilicity, currently the chromatographic approach is mostly used. Among chromatographic methods used for lipophilicity assessment, thin layer chromatography (TLC) is still one of the most popular tools. The main goal of this study was to compare classical reversed-phase thin layer chromatography (RP-TLC) and micellar TLC as potential tools for lipophilicity assessment. Micellar liquid chromatography has significantly lover environment impact than classical reversed-phase liquid chromatography. Additionally comparison of cationic and anionic surfactants (CTAB and SDS), which have different chemical properties, as modifiers of mobile phase in micellar TLC were investigated. The Quantitative Structure-Retention Relationships (QSRR) approach was used in order to present molecular mechanisms of retention in investigated chromatographic systems. The study was based on chemically diverse model set compounds, with a proved therapeutic or toxic potential. According to obtained results the micellar TLC with CTAB as surfactant can be recommended to logP prediction. The obtained QSRR models indicated that adsorption of CTAB monomers on CN modified surface of silica gel and the silanol-quaternary ammonium interactions are possible. Consequently, the reduction of interaction between molecules and free silanol, contributes to the improvement of logP predictions. These result were confirmed by regression and classification methods.

Thin layer chromatography in drug discovery process.

The review is mainly focused on application of thin layer chromatography (TLC) as simple, rapid and inexpensive method for lipophilicity assessment. Among separation techniques, TLC is still one of the most popular for lipophilicity measurement. The principles and methodology of Quantitative Structure Retention Relationship (QSRR) employed to lipophilicity prediction from retention data are presented. Moreover, applications of TLC retention constants in Quantitative Structure Activity Relationship (QSAR) studies were critically overviewed. The paper concerns also bioautography as a TLC method complementary to QSAR studies. In the article, the advantages and limitations of well established and less common planar chromatography modes applied for drug discovery process were discussed.