An effect of choline lactate based low transition temperature mixtures on the lipase catalytic properties.

A new series of low transition temperature mixures (LTTM) based on choline lactate quaternary ammonium salt and various hydrogen bond donors was prepared and characterized towards their physicochemical properties and usability as an enzymatic reaction mixture for lipase-catalyzed transesterification reactions. Studies of low transition temperature mixtures have shown a long-term stabilizing effect for lipase as well as a positive influence on lipase thermal stability. In the case of Ch[Lac]:Gly: EthGly increasing the stability of lipase by 8 °C (up to 55.2 °C) compared to the control sample. Conducted transesterification reactions were characterized by high yields - up to 98% - and high purity of the obtained products.

Acceleration of lactose hydrolysis using beta-galactosidase and deep eutectic solvents.

A series of new deep eutectic solvents based on choline levulinate and various hydrogen bond donors were prepared and characterized by1H NMR, FT-IR, TG, and DSC. In particular, their physicochemical properties (density, viscosity, conductivity, and thermal stability) were determined and their usability as an enhancing additive to the enzymatic reaction mixture, for the enzyme was checked. It has been shown, that prepared DES, exhibits low viscosity (at 40 °C within the range 0.1-0.8 Pa·s), high thermal stability (in almost all cases above 150 °C), and density within the range 1.1-1.17 g cm-3. Also, it has been shown, that obtained mixtures can stabilize the enzymes, and positively influence on its activity. The addition of up to 15% (v/v) of DES mixture composed of choline levulinate: ethylene glycol, enhanced more than threefold lactose hydrolysis yield by ß-galactosidase. The present study shows the relevance of the newly designed DES series for improving enzymes properties with the potential to apply in the effective conversion of food processing origin substrates.

Synthesis, characterization and biological activity of bifunctional ionic liquids based on dodine ion.

BACKGROUND: Development of new plant protection strategies has become an urgent matter in modern agriculture, in view of the evidently proved negative effect of currently used active ingredients of pesticides. In recent years, much effort has been made to eliminate the use of pesticides established to be toxic to pollinators. RESULTS: In this study, we present a group of new bifunctional ionic liquids based on dodine (N-dodecylguanidine) cation whose physical and biological properties have been modified relative to those of the commercially available N-dodecylguanidine acetate. The decreased level of residue of active substances in plant tissues reduces their availability to pollinators, which increases the safety of their use. Moreover, lower environmental impact in combination with high antifungal activity and an additional biological function, that is the systemic acquired resistance induction, are in line with the goals of sustainable agriculture. CONCLUSION: The presented approach shows the possibility of derivatization of commonly used fungicide into the form of bifunctional salts whose physical and biological properties can be easily modified. The paper reports successful design and synthesis of new sustainable and green chemicals for the modern agriculture, being less toxic to the environment and human health but still effective against pathogens. © 2021 Society of Chemical Industry.

Deep eutectic solvents based on choline cation - Physicochemical properties and influence on enzymatic reaction with ß-galactosidase.

In presented study analysis of physicochemical properties of deep eutectic solvents (DESs) and their usefulness as an element of reaction medium for ß-galactosidase from Kluyveromyces lactis was conducted. Analyzed DESs were based on choline salt derivatives: choline chloride, choline acetate and hydrogen bond-donors (HBD) such as: glycerol, ethylene glycol, urea, thiourea and levulinic acid. Results showed that reaction medium with appropriate amount of DES based on choline acetate had beneficial effect on activity of ß-galactosidase. The 5% (v/v) addition of developed choline acetate:glycerol DES mixture enhanced enzyme activity almost three fold. The results of performed experiments have also revealed that ß-galactosidase activity is less affected by the organic anion as choline acetate in ionic liquid, than inorganic anion as choline chloride. The developed green solvents as DES based on choline acetate exhibit a wide application potential that can be used to increase efficiency of enzyme-based industrial process.

Downregulation of CEACAM6 gene expression in laryngeal squamous cell carcinoma is an effect of DNA hypermethylation and correlates with disease progression.

We have turned our attention to CEACAM6 gene, already described as deregulated in various types of cancer. By using the expression microarrays performed on the set of 16 laryngeal squamous cell carcinoma (LSCC) samples: 11 cell lines and 5 primary tumors we have shown downregulation of CEACAM6 gene as compared to non cancer controls from head and neck region. CEACAM6 gene downregulation, further confirmed by quantitative PCR on 25 LSCC cell lines, was observed in cell lines derived from recurrent tumors in comparison to controls. A significant gene downregulation was observed in cell lines derived from advanced, high grade tumors in comparison to controls. Intrigued by the recurrent transcriptional loss of CEACAM6 we searched for the mechanism potentially responsible for its downregulation and hence we analyzed DNA copy number changes (a-CGH), promoter DNA methylation status and occurrence of gene mutations (in silico). Neither the analysis of gene copy number, nor the mutation screen has shown recurrent deletions or mutations, that could contribute to the observed downregulation of the gene. However, by using bisulfite pyrosequencing, we have shown DNA hypermethylation (mean DNA methylation > 78%) of CEACAM6 promoter region in 9/25 (36%) LSCC cell lines. Importantly, the 5-aza-2-deoxycytidine-induced inhibition of DNA methylation resulted in restoration of CEACAM6 expression in the two LSCC cell lines on mRNA level. In summary, we have shown that recurrent downregulation of CEACAM6 in LSCC is dependent on the gene's promoter DNA methylation and is observed predominantly in large, poorly differentiated tumors and recurrences.

Recurrent transcriptional loss of the PCDH17 tumor suppressor in laryngeal squamous cell carcinoma is partially mediated by aberrant promoter DNA methylation.

Protocadherins are cell-cell adhesion molecules encoded by a large family of genes. Recent reports demonstrate recurrent silencing of protocadherin genes in tumors and provide strong arguments for their tumor supresor functionality. Loss of protocadherins may contribute to cancer development not only by altering cell-cell adhesion, that is a hallmark of cancer, but also by enhancing proliferation and epithelial mesenchymal transition of cells via deregulation of the WNT signaling pathway. In this study we have further corroborated our previous findings on the involvement of PCDH17 in laryngeal squamous cell carcinoma (LSCC). We used bisulfite pyrosequencing to analyze a cohort of primary LSCC tumors for alterations in PCDH17 promoter DNA methylation as an alternative gene inactivation mechanism to the homozygous deletions reported earlier. Moreover, we analyzed primary LSCC samples by immunohistochemistry for PCDH17 protein loss. We identified recurrent elevation of PCDH17 promoter DNA methylation in 32/81 (40%) primary tumors (P < 0.001) and therein hypermethylation of 12 (15%) cases in contrast to no tumor controls (n = 24) that were all unmethylated. Importantly, DNA demethylation by decitabine has restored low level PCDH17 expression in LSCC cell lines. In conclusion, we provide a mechanistic explanation of recurrently observed PCDH17 silencing in LSCC by demonstrating the role of promoter methylation in this process. In light of these findings and recent reports showing that PCDH17 methylation is detectable in serum of cancer patients we suggest that testing PCDH17 DNA methylation might serve as a potential biomarker in LSCC.

Combined deletion and DNA methylation result in silencing of FAM107A gene in laryngeal tumors.

Larynx squamous cell carcinoma (LSCC) is characterized by complex genotypes, with numerous abnormalities in various genes. Despite the progress in diagnosis and treatment of this disease, 5-year survival rates remain unsatisfactory. Therefore, the extended studies are conducted, with the aim to find genes, potentially implicated in this cancer. In this study, we focus on the FAM107A (3p14.3) gene, since we found its significantly reduced expression in LSCC by microarray profiling (Affymetrix U133 Plus 2.0 array). By RT-PCR we have confirmed complete FAM107A downregulation in laryngeal cancer cell lines (15/15) and primary tumors (21/21) and this finding was further supported by FAM107A protein immunohistochemistry (15/15). We further demonstrate that a combined two hit mechanism including loss of 3p and hypermethylation of FAM107A promoter region (in 9/15 cell lines (p < 0.0001) and in 15/21 primary tumors (p < 0.0001)) prevails in the gene transcriptional loss. As a proof of principle, we show that Decitabine - a hypomethylating agent - restores FAM107A expression (5 to 6 fold increase) in the UT-SCC-29 cell line, characterized by high DNA methylation. Therefore, we report the recurrent inactivation of FAM107A in LSCC, what may suggest that the gene is a promising tumor suppressor candidate involved in LSCC development.

Recurrent epigenetic silencing of the PTPRD tumor suppressor in laryngeal squamous cell carcinoma.

Cellular processes like differentiation, mitotic cycle, and cell growth are regulated by tyrosine kinases with known oncogenic potential and tyrosine phosphatases that downmodulate the first. Therefore, tyrosine phosphatases are recurrent targets of gene alterations in human carcinomas. We and others suggested recently a tumor suppressor function of the PTPRD tyrosine phosphatase and reported homozygous deletions of the PTPRD locus in laryngeal squamous cell carcinoma. In this study, we investigated other gene-inactivating mechanisms potentially targeting PTPRD, including loss-of-function mutations and also epigenetic alterations like promoter DNA hypermethylation. We sequenced the PTPRD gene in eight laryngeal squamous cell carcinoma cell lines but did not identify any inactivating mutations. In contrast, by bisulfite pyrosequencing of the gene promoter region, we identified significantly higher levels of methylation (p = 0.001 and p = 0.0002, respectively) in 9/14 (64%) laryngeal squamous cell carcinoma cell lines and 37/79 (47%) of primary laryngeal squamous cell carcinoma tumors as compared to normal epithelium of the upper aerodigestive tract. There was also a strong correlation (p = 0.0001) between methylation and transcriptional silencing for the PTPRD gene observed in a cohort of 497 head and neck tumors from The Cancer Genome Atlas dataset suggesting that DNA methylation is the main mechanism of PTPRD silencing in these tumors. In summary, our data provide further evidence of the high incidence of PTPRD inactivation in laryngeal squamous cell carcinoma. We suggest that deletions and loss-of-function mutations are responsible for PTPRD loss only in a fraction of cases, whereas DNA methylation is the dominating mechanism of PTPRD inactivation.