Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
Add more filters










Publication year range
1.
OMICS ; 28(2): 76-89, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38271566

ABSTRACT

Gastric cancer (GC) remains a leading cause of cancer-related mortality globally. This is due to the fact that majority of the cases of GC are diagnosed at an advanced stage when the treatment options are limited and prognosis is poor. The diffuse subtype of gastric cancer (DGC) under Lauren's classification is more aggressive and usually occurs in younger patients than the intestinal subtype. The concept of personalized medicine is leading to the identification of multiple biomarkers in a large variety of cancers using different combinations of omics technologies. Proteomic changes including post-translational modifications are crucial in oncogenesis. We analyzed the phosphoproteome of DGC by using paired fresh frozen tumor and adjacent normal tissue from five patients diagnosed with DGC. We found proteins involved in the epithelial-to-mesenchymal transition (EMT), c-MYC pathway, and semaphorin pathways to be differentially phosphorylated in DGC tissues. We identified three kinases, namely, bromodomain adjacent to the zinc finger domain 1B (BAZ1B), WNK lysine-deficient protein kinase 1 (WNK1), and myosin light-chain kinase (MLCK) to be hyperphosphorylated, and one kinase, AP2-associated protein kinase 1 (AAK1), to be hypophosphorylated. LMNA hyperphosphorylation at serine 392 (S392) was demonstrated in DGC using immunohistochemistry. Importantly, we have detected heparin-binding growth factor (HDGF), heat shock protein 90 (HSP90), and FTH1 as potential therapeutic targets in DGC, as drugs targeting these proteins are currently under investigation in clinical trials. Although these new findings need to be replicated in larger study samples, they advance our understanding of signaling alterations in DGC, which could lead to potentially novel actionable targets in GC.


Subject(s)
Stomach Neoplasms , Humans , Stomach Neoplasms/genetics , Precision Medicine , Proteomics , Phosphorylation , Carcinogenesis , Bromodomain Containing Proteins , Transcription Factors/metabolism
2.
Front Pharmacol ; 14: 1135898, 2023.
Article in English | MEDLINE | ID: mdl-37724182

ABSTRACT

Delphinium roylei Munz is an indigenous medicinal plant to India where its activity against cancer has not been previously investigated, and its specific interactions of bioactive compounds with vulnerable breast cancer drug targets remain largely unknown. Therefore, in the current study, we aimed to evaluate the anti-breast cancer activity of different extracts of D. roylei against breast cancer and deciphering the molecular mechanism by Network Pharmacology combined with Molecular Docking and in vitro verification. The experimental plant was extracted with various organic solvents according to their polarity index. Phytocompounds were identified by High resolution-liquid chromatography-mass spectrometry (HR-LC/MS) technique, and SwissADME programme evaluated their physicochemical properties. Next, target(s) associated with the obtained bioactives or breast cancer-related targets were retrieved by public databases, and the Venn diagram selected the overlapping targets. The networks between overlapping targets and bioactive were visualized, constructed, and analyzed by STRING programme and Cytoscape software. Finally, we implemented a molecular docking test (MDT) using AutoDock Vina to explore key target(s) and compound(s). HR-LC/MS detected hundreds of phytocompounds, and few were accepted by Lipinski's rules after virtual screening and therefore classified as drug-like compounds (DLCs). A total of 464 potential target genes were attained for the nine quantitative phytocompounds and using Gene Cards, OMIM and DisGeNET platforms, 12063 disease targets linked to breast cancer were retrieved. With Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment, a total of 20 signalling pathways were manifested, and a hub signalling pathway (PI3K-Akt signalling pathway), a key target (Akt1), and a key compound (8-Hydroxycoumarin) were selected among the 20 signalling pathways via molecular docking studies. The molecular docking investigation revealed that among the nine phytoconstituents, 8-hydroxycoumarin showed the best binding energy (-9.2 kcal/mol) with the Akt1 breast cancer target. 8-hydroxycoumarin followed all the ADME property prediction using SwissADME, and 100 nanoseconds (ns) MD simulations of 8-hydroxycoumarin complexes with Akt1 were found to be stable. Furthermore, D. roylei extracts also showed significant antioxidant and anticancer activity through in vitro studies. Our findings indicated for the first time that D. roylei extracts could be used in the treatment of BC.

3.
Pharmaceutics ; 14(6)2022 Jun 13.
Article in English | MEDLINE | ID: mdl-35745829

ABSTRACT

(1) Background: Inflammation is one of the primary responses of the immune system and plays a key role in the pathophysiology of various diseases. Recent reports suggest that various phytochemicals exhibit promising anti-inflammatory and immunomodulation activities with relatively few undesirable effects, thus offering a viable option to deal with inflammation and associated diseases. The current study evaluates the anti-inflammatory and immunomodulatory effects of withaferin A (WA) in immune cells extracted from BALB/c mice. (2) Methods: MTT assays were performed to assess the cell viability of splenocytes and anti-inflammatory doses of WA. Under aseptic conditions, the isolation of macrophages and splenocytes from BALB/c mice was performed to investigate the anti-inflammatory effects of WA. Analysis of the expression of proinflammatory cytokines and associated signaling mediators was performed using proinflammatory assay kits, real-time polymerase chain reaction (RT-PCR), and immunoblotting, while the quantification of B and T cells was performed by flow cytometry. (3) Results: Our results demonstrated that WA exhibits anti-inflammatory and immunomodulatory effects in LPS-stimulated macrophages and splenocytes derived from BALB/c mice, respectively. Mechanistically, we found that WA promotes an anti-inflammatory effect on LPS-stimulated macrophages by attenuating the secretion and expression of proinflammatory cytokines TNF-α, IL-1ß, IL-6, and the inflammation modulator NO, both at the transcriptional and translational level, respectively. Further, WA inhibits LPS-stimulated inflammatory signaling by dephosphorylation of p-Akt-Ser473 and p-ERK1/2. This dephosphorylation does not allow IĸB-kinase activation to disrupt IĸB-NF-ĸB interaction. The consistent interaction of IĸB with NF-ĸB in WA-treated cells attenuates the activation of downstream inflammatory signaling mediators Cox-2 and iNOS expression, which play crucial roles in inflammatory signaling. Additionally, we observed significant immunomodulation of LPS-stimulated spleen-derived lymphocytes by suppression of B (CD19) and T (CD4+/CD8+) cell populations after treatment with WA. (4) Conclusion: WA exhibits anti-inflammatory and immunomodulatory activity by modulating Akt/ERK/NF-kB-mediated inflammatory signaling in macrophages and immunosuppression of B (CD19) and T cell (CD4+/CD8+) populations in splenocytes after LPS stimulation. These results suggest that WA could act as a potential anti-inflammatory/immunomodulatory molecule and support its use in the field of immunopharmacology to modulate immune system cells.

4.
Cancers (Basel) ; 13(23)2021 Nov 25.
Article in English | MEDLINE | ID: mdl-34885041

ABSTRACT

Gastric cancer is a leading cause of death from cancer globally. Gastric cancer is classified into intestinal, diffuse and indeterminate subtypes based on histology according to the Laurén classification. The intestinal and diffuse subtypes, although different in histology, demographics and outcomes, are still treated in the same fashion. This study was designed to discover proteomic signatures of diffuse and intestinal subtypes. Mass spectrometry-based proteomics using tandem mass tags (TMT)-based multiplexed analysis was used to identify proteins in tumor tissues from patients with diffuse or intestinal gastric cancer with adjacent normal tissue control. A total of 7448 or 4846 proteins were identified from intestinal or diffuse subtype, respectively. This quantitative mass spectrometric analysis defined a proteomic signature of differential expression across the two subtypes, which included gremlin1 (GREM1), bcl-2-associated athanogene 2 (BAG2), olfactomedin 4 (OLFM4), thyroid hormone receptor interacting protein 6 (TRIP6) and melanoma-associated antigen 9 (MAGE-A9) proteins. Although GREM1, BAG2, OLFM4, TRIP6 and MAGE-A9 have all been previously implicated in tumor progression and metastasis, they have not been linked to intestinal or diffuse subtypes of gastric cancer. Using immunohistochemical labelling of a tissue microarray comprising of 124 cases of gastric cancer, we validated the proteomic signature obtained by mass spectrometry in the discovery cohort. Our findings should help investigate the pathogenesis of these gastric cancer subtypes and potentially lead to strategies for early diagnosis and treatment.

5.
Article in English | MEDLINE | ID: mdl-34956401

ABSTRACT

Colorectal cancer (CRC) is one of the globally prevalent and virulent types of cancer with a distinct alteration in chromosomes. Often, any alterations in the adenomatosis polyposis coli (APC), a tumor suppressor gene, and methylenetetrahydrofolate reductase (MTHFR) gene are related to surmise colorectal cancer significantly. In this study, we have investigated chromosomal and gene variants to discern a new-fangled gene and its expression in the southern populations of India by primarily spotting the screened APC and MTHFR variants in CRC patients. An equal number of CRC patients and healthy control subjects (n = 65) were evaluated to observe a chromosomal alteration in the concerted and singular manner for APC and MTHFR genotypes using standard protocols. The increasing prognosis was observed in persons with higher alcoholism and smoking (P < 0.05) with frequent alterations in chromosomes 1, 5, 12, 13, 15, 17, 18, 21, and 22. The APC Asp 1822Val and MTHFR C677T genotypes provided significant results, while the variant alleles of this polymorphism were linked with an elevated risk of CRC. Chromosomal alterations can be the major cause in inducing carcinogenic outcomes in CRCs and can drive to extreme pathological states.


Subject(s)
Adenomatous Polyposis Coli Protein/genetics , Colorectal Neoplasms , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Colorectal Neoplasms/genetics , Genetic Predisposition to Disease , Genotype , Humans , Polymorphism, Genetic , Risk Factors
6.
Clin Ther ; 43(12): 2127-2135, 2021 12.
Article in English | MEDLINE | ID: mdl-34794834

ABSTRACT

PURPOSE: This study was conducted to examine and verify the use of saliva as an alternative matrix for monitoring phenytoin drug levels in patients with epilepsy. Drug concentrations are measured to evaluate whether a suitable drug level has been achieved to minimize the risk for toxicity, inadequate efficacy, or therapy resistance and compliance issues. METHODS: Quantitative analysis was performed by using reverse-phase HPLC after sample pretreatment with acetonitrile. Seventy-eight patients who met the inclusion/exclusion criteria were examined in this study. Trough concentrations of both saliva and serum were taken at steady state. FINDINGS: Of the 78 patients enrolled, only 11 (14.1%) had normal levels. Twenty-eight patients (35.9%) had subtherapeutic levels, and 39 (50%) had toxic levels. Simultaneously, salivary phenytoin levels were analyzed; only 13 patients (17.3%) had therapeutic levels, 25 patients (33.3%) had subtherapeutic levels, and 37 (49.3%) had toxic levels. Among the study population, most of the patients were aged 31 to 40 years (25.6%) followed by the age group 21 to 30 years (19.2%). The lowest percentage of patients were in the age groups 71 to 80 years and >80 years (1.3%) each. This study found a statistically significant relationship between free serum and salivary phenytoin levels (P < 0.001). A very weak and insignificant correlation was observed between serum/salivary phenytoin levels and sex/age of the study population. The results of the present study support the use of saliva as an alternative to serum/plasma for monitoring phenytoin therapy. IMPLICATIONS: The free concentration of a drug represents the freely diffusible drug fraction, which is the therapeutically active form. Accordingly, the free drug concentration correlates to clinical efficacy and drug toxicity better than total concentration.


Subject(s)
Epilepsy , Saliva , Adult , Aged , Aged, 80 and over , Chromatography, High Pressure Liquid , Drug Monitoring , Epilepsy/drug therapy , Humans , Phenytoin , Young Adult
7.
Expert Rev Proteomics ; 18(9): 737-756, 2021 09.
Article in English | MEDLINE | ID: mdl-34602018

ABSTRACT

INTRODUCTION: Proteomics has played a pivotal role in identifying proteins perturbed in disease conditions when compared with healthy samples. Study of dysregulated proteins aids in identifying diagnostic markers and potential therapeutic targets. Cancer is an outcome of interplay of several such disarrayed proteins and molecular pathways which perturb cellular homeostasis, resulting in transformation. In this review, we discuss various facets of proteomic approaches, including tools and technological advancements, aiding in understanding differentially expressed molecules and signaling mechanisms. AREAS COVERED: In this review, we have taken the approach of documenting the different methods of proteomic studies, ranging from labeling techniques, data analysis methods, and the nature of molecule detected. We summarize each technique and provide a glimpse of cancer research carried out using them, highlighting the advantages and drawbacks in comparison with others. Literature search using online resources, such as PubMed and Google Scholar were carried out for this approach. EXPERT OPINION: Technological advancements in proteomics studies have come a long way from the study of two-dimensional mapping of proteins separated on gels in the early 1970s. Higher precision in molecular identification and quantification (high throughput), and greater number of samples analyzed have been the focus of researchers.


Subject(s)
Neoplasms , Proteomics , Humans , Neoplasms/genetics , Proteins
8.
Curr Cancer Drug Targets ; 21(10): 813-828, 2021.
Article in English | MEDLINE | ID: mdl-34365922

ABSTRACT

The final stage of breast cancer involves spreading breast cancer cells to the vital organs like the brain, liver lungs and bones in the process called metastasis. Once the target organ is overtaken by the metastatic breast cancer cells, its usual function is compromised causing organ dysfunction and death. Despite the significant research on breast cancer metastasis, it's still the main culprit of breast cancer-related deaths. Exploring the complex molecular pathways associated with the initiation and progression of breast cancer metastasis could lead to the discovery of more effective ways of treating the devastating phenomenon. The present review article highlights the recent advances to understand the complexity associated with breast cancer metastases, organotropism and therapeutic advances.


Subject(s)
Breast Neoplasms , Breast Neoplasms/drug therapy , Female , Humans , Neoplasm Metastasis
9.
Sci Rep ; 11(1): 9397, 2021 04 30.
Article in English | MEDLINE | ID: mdl-33931671

ABSTRACT

Shammah is a smokeless tobacco product often mixed with lime, ash, black pepper and flavorings. Exposure to shammah has been linked with dental diseases and oral squamous cell carcinoma. There is limited literature on the prevalence of shammah and its role in pathobiology of oral cancer. In this study, we developed a cellular model to understand the effect of chronic shammah exposure on oral keratinocytes. Chronic exposure to shammah resulted in increased proliferation and invasiveness of non-transformed oral keratinocytes. Quantitative proteomics of shammah treated cells compared to untreated cells led to quantification of 4712 proteins of which 402 were found to be significantly altered. In addition, phosphoproteomics analysis of shammah treated cells compared to untreated revealed hyperphosphorylation of 36 proteins and hypophosphorylation of 83 proteins (twofold, p-value ≤ 0.05). Bioinformatics analysis of significantly altered proteins showed enrichment of proteins involved in extracellular matrix interactions, necroptosis and peroxisome mediated fatty acid oxidation. Kinase-Substrate Enrichment Analysis showed significant increase in activity of kinases such as ROCK1, RAF1, PRKCE and HIPK2 in shammah treated cells. These results provide better understanding of how shammah transforms non-neoplastic cells and warrants additional studies that may assist in improved early diagnosis and treatment of shammah induced oral cancer.


Subject(s)
Keratinocytes/metabolism , Mouth/metabolism , Phosphoproteins/metabolism , Proteome/metabolism , Tobacco, Smokeless/adverse effects , Cells, Cultured , Humans , Keratinocytes/drug effects , Mouth/drug effects , Proteome/analysis , Proteome/drug effects , Signal Transduction
10.
OMICS ; 25(4): 255-268, 2021 04.
Article in English | MEDLINE | ID: mdl-33794113

ABSTRACT

Tobacco abuse is a major risk factor associated with the development of oral squamous cell carcinoma. Differences in molecular aberrations induced by tobacco exposure by chewing or smoking form are not well studied in case of oral cancer. We used tandem mass tag-based quantitative proteomic approach to delineate proteomic alterations in oral cancer patients based on their history of tobacco using habits (patients who chewed tobacco, patients who smoked tobacco, and those with no history of tobacco consumption). Our data identified distinct dysregulation of biological processes and pathways in each patient cohort. Bioinformatics analysis of dysregulated proteins identified in our proteomic study revealed dysregulation of collagen formation and antigen processing/presentation pathway in oral cancer patients who smoked tobacco, whereas proteins associated with the process of keratinization showed enrichment in patients who chewed tobacco. In addition, we identified overexpression of proteins involved in immune pathways and downregulation of muscle contraction-mediated signaling events in all three cohorts, irrespective of tobacco using habits. This study lays the groundwork for identification of protein markers that may aid in identification of high-risk patients for cancer development based on the history of tobacco exposure habits.


Subject(s)
Carcinoma, Squamous Cell , Mouth Neoplasms , Habits , Humans , Mouth Neoplasms/genetics , Proteomics , Risk Factors , Nicotiana
11.
J Gastrointest Cancer ; 52(3): 1022-1028, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33047269

ABSTRACT

PURPOSE: Colorectal cancer (CRC) is one of the recurring and lethal gastrointestinal tract disease rankings as the primary cause of worldwide morbidity and mortality. In general, the tumour node metastasis (TNM) and Dukes classification assist in diagnosis, prognosis and treatments of CRC along with haematological examinations and tumour demographic characterisations in patients. METHODS: The present investigation is carried out on clinically acknowledged sixty-five CRC patients based on haematological findings and are sorted into stages using TNM and Dukes. The present study is to find the association between haematological findings, demographic characters, differentiation position, lymph node invasion and tumour node metastasis in CRC patients in accordance with their age. RESULTS: We observed significant (p < 0.05) nexus between lymph node metastasis and tumour node metastasis on the basis of tumour's differentiation demographic positioning and age of the individuals. CONCLUSION: Earlier location tracing and medicinal treatment or surgery lessen the chance of CRC morbidity and mortality along with prolonging survival rate via prognostic factors and disease position determination.


Subject(s)
Colorectal Neoplasms/epidemiology , Colorectal Neoplasms/pathology , Neoplasm Grading/statistics & numerical data , Neoplasm Staging/statistics & numerical data , Adult , Aged , Colorectal Neoplasms/blood , Female , Humans , India/epidemiology , Lymphatic Metastasis/pathology , Male , Middle Aged , Prognosis , Risk Factors
12.
J Cell Commun Signal ; 12(4): 745-751, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30191398

ABSTRACT

Interferon gamma (IFN-γ), is a cytokine, which is an important regulator of host defense system by mediating both innate and adaptive immune responses. IFN-γ signaling is primarily associated with inflammation and cell-mediated immune responses. IFN-γ is also represented as antitumor cytokine which facilitates immunosurveillance in tumor cells. In addition, IFN-γ mediated signaling also elicits pro-tumorigenic transformations and promotes tumor progression. Impact of IFN-γ signaling in mammalian cells has been widely studied which indicate that IFN-γ orchestrates distinct cellular functions including immunomodulation, leukocyte trafficking, apoptosis, anti-microbial, and both anti- and pro-tumorigenic role. However, a detailed network of IFN-γ signaling pathway is currently lacking. Therefore, we systematically curated the literature information pertaining to IFN-γ signaling and develop a comprehensive signaling network to facilitate better understanding of IFN-γ mediated signaling. A total of 124 proteins were catalogued that were experimentally proven to be involved in IFN-γ signaling cascade. These 124 proteins were found to participate in 81 protein-protein interactions, 94 post-translational modifications, 20 translocation events, 54 activation/inhibiton reactions. Further, 236 differential expressed genes were also documented in IFN-γ mediated signaling. IFN-γ signaling pathway is made freely available to scientific audience through NetPath at ( http://www.netpath.org/pathways?path_id=NetPath_32 ). We believe that documentation of reactions pertaining to IFN-γ signaling and development of pathway map will facilitate further research in IFN-γ associated human diseases including cancer.

13.
Sci Rep ; 8(1): 7040, 2018 05 04.
Article in English | MEDLINE | ID: mdl-29728663

ABSTRACT

Carcinogenic effect of tobacco in oral cancer is through chewing and/or smoking. Significant differences exist in development of oral cancer between tobacco users and non-users. However, molecular alterations induced by different forms of tobacco are yet to be fully elucidated. We developed cellular models of chronic exposure to chewing tobacco and cigarette smoke using immortalized oral keratinocytes. Chronic exposure to tobacco resulted in increased cell scattering and invasiveness in immortalized oral keratinocytes. miRNA sequencing using Illumina HiSeq 2500 resulted in the identification of 10 significantly dysregulated miRNAs (4 fold; p ≤ 0.05) in chewing tobacco treated cells and 6 in cigarette smoke exposed cells. We integrated this data with global proteomic data and identified 36 protein targets that showed inverse expression pattern in chewing tobacco treated cells and 16 protein targets that showed inverse expression in smoke exposed cells. In addition, we identified 6 novel miRNAs in chewing tobacco treated cells and 18 novel miRNAs in smoke exposed cells. Integrative analysis of dysregulated miRNAs and their targets indicates that signaling mechanisms leading to oncogenic transformation are distinct between both forms of tobacco. Our study demonstrates alterations in miRNA expression in oral cells in response to two frequently used forms of tobacco.


Subject(s)
Gene Expression Regulation , Keratinocytes/metabolism , MicroRNAs/genetics , Mouth Mucosa/cytology , Smoking , Tobacco, Smokeless , Biomarkers , Computational Biology/methods , Environmental Exposure/adverse effects , Humans , Keratinocytes/pathology , Phenotype
14.
Mitochondrion ; 40: 58-70, 2018 05.
Article in English | MEDLINE | ID: mdl-29042306

ABSTRACT

Cellular transformation owing to cigarette smoking is due to chronic exposure and not acute. However, systematic studies to understand the molecular alterations in lung cells due to cigarette smoke are lacking. To understand these molecular alterations induced by chronic cigarette smoke exposure, we carried out tandem mass tag (TMT) based temporal proteomic profiling of lung cells exposed to cigarette smoke for upto 12months. We identified 2620 proteins in total, of which 671 proteins were differentially expressed (1.5-fold) after 12months of exposure. Prolonged exposure of lung cells to smoke for 12months revealed dysregulation of oxidative phosphorylation and overexpression of enzymes involved in TCA cycle. In addition, we also observed overexpression of enzymes involved in glutamine metabolism, fatty acid degradation and lactate synthesis. This could possibly explain the availability of alternative source of carbon to TCA cycle apart from glycolytic pyruvate. Our data indicates that chronic exposure to cigarette smoke induces mitochondrial metabolic reprogramming in cells to support growth and survival.


Subject(s)
Cigarette Smoking/adverse effects , Lung/pathology , Metabolism/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Smoke/adverse effects , Cell Line, Tumor , Humans , Proteome/analysis
15.
J Biotechnol ; 200: 52-8, 2015 Apr 20.
Article in English | MEDLINE | ID: mdl-25711178

ABSTRACT

Substrates present in aggregated forms, such as micelles, are often poorly converted by enzymes. Alkyl glycosides constitute typical examples and the critical micelle concentration (CMC) decreases with increasing length of the alkyl group. In this study, possibilities to hydrolyse alkyl glycosides by glycoside hydrolases were explored, and α-cyclodextrin was used as an agent to form inclusion complexes with the alkyl glycosides, thereby preventing micelle formation. The cyclodextrin complexes were accepted as substrates by the enzymes to variable extent. The ß-glucosidases originating from Thermotoga neapolitana (Tn Bgl3B) and from almond were not at all able to hydrolyse alkyl ß-glucosides in the presence of 100mM α-cyclodextrin. However, Aspergillus niger amyloglucosidase readily accepted the complexes as substrates. In reactions involving decyl and dodecyl maltosides, the presence of 100mM α-cyclodextrin caused an increase in reaction rate in most cases, especially at high substrate concentrations. Surprisingly, the amyloglucosidase-catalyzed hydrolysis of octyl-ß-maltoside to glucose and ß-octylglucoside was faster in the presence of α-cyclodextrin than without, even at substrate concentrations below CMC. A possible explanation of the observed rate enhancement is that binding sites on the carbohydrate binding domain of amyloglucosidase, known to bind cyclodextrins, help to guide the alkyl glycoside-cyclodextrin complex to the active site, and thereby promote its conversion.


Subject(s)
Glycoside Hydrolases/chemistry , Glycosides/chemistry , alpha-Cyclodextrins/chemistry , Aspergillus niger/enzymology , Bacterial Proteins/chemistry , Fungal Proteins/chemistry , Hydrolysis , Micelles , Plant Proteins/chemistry , Prunus dulcis/enzymology , Thermotoga neapolitana/enzymology
16.
J Biotechnol ; 165(1): 63-8, 2013 May 10.
Article in English | MEDLINE | ID: mdl-23473992

ABSTRACT

Enzymatic synthesis of oligosaccharides with absolute stereo-selectivity and regio-selectivity provides an economical alternative to classical chemical methods. Here we demonstrate, for the first time, that whole cells of P. etchellsii are highly efficient biocatalysts and can be used for oligosaccharide synthesis using p-nitrophenyl-ß-D-glucopyranoside, o-nitrophenyl-ß-D-glucopyranoside and p-nitrophenyl-ß-D-xylopyranoside as both donors and acceptors. Auto-condensation of p-nitrophenyl-ß-D-glucopyranoside and o-nitrophenyl-ß-D-glucopyranoside resulted in formation of ß-(1→6) linked disaccharide as major products in 4 and 12% yield respectively. By contrast, auto condensation of p-nitrophenyl-ß-D-xylopyranoside exclusively lead to formation of ß-(1→4) linked disaccharide in 24% yield.


Subject(s)
Glycoside Hydrolases , Oligosaccharides/biosynthesis , Pichia/enzymology , Glucosides/chemistry , Glycoside Hydrolases/chemistry , Glycoside Hydrolases/metabolism , Glycosides/chemistry , Humans , Pichia/genetics
17.
Bioresour Technol ; 107: 287-94, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22225608

ABSTRACT

In the present study, we have investigated the use of Pichia etchellsii whole cells for synthesis of long-chain alkyl glucosides. Methyl-ß-d-glucopyranoside (MG) was used in reaction with fatty alcohols, n-hexanol, n-octanol, n-decanol and n-dodecanol to synthesize the respective alkyl glucosides. The initial reaction conditions were first optimized at 2.5 ml scale for synthesis of octyl glucoside (OG) and were 8% water content, 100mM MG and 6h of reaction time and this resulted in ≈ 53% yield. A maximum transglucosylation/hydrolysis ratio of 2.79 was obtained at 100mM MG favoring high product yield. Based on the optimized conditions, a reactor was operated at 50 ml level which resulted in ≈ 60% conversion of MG to OG. A simple high performance liquid chromatography method was developed for quantitation of higher chain glucosides using a refractive index detector. A maximum of 27% and 13% yield was obtained for decyl-, and dodecyl-ß-d-glucopyranoside, respectively.


Subject(s)
Methylglucosides/metabolism , Pichia/enzymology , beta-Glucosidase/metabolism , Biotransformation , Chromatography, High Pressure Liquid , Hydrolysis , Substrate Specificity
18.
J Biotechnol ; 150(4): 490-6, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20932864

ABSTRACT

Octyl-ß-D-glucopyranoside was synthesized by transglucosylation between p-nitrophenyl ß-D-glucopyranoside (pNPG) and octanol as an acceptor using whole cells of thermo tolerant yeast Pichia etchellsii displaying cell wall bound ß-glucosidase. Effect of several parameters such as glucosyl donor concentration, enzyme units and initial water activity was studied to optimize product yield. An initial water activity interval of 0.33-0.64 was favorable and increase in total enzyme units had marginal effect on conversion yield. An empirical model was developed to describe the relationship between various parameters and octyl glucoside yield. These factors were combined in a batch replacement strategy whereby octyl-ß-D-glucopyranoside was synthesized in 4h to a concentration of 30 mM (9.25 mg/ml) with a conversion yield of nearly 70% with pNPG as a glucosyl donor. Quantitative analysis was done by a highly reproducible reverse-phase high-performance liquid chromatography (RP-HPLC) method and detection was achieved using refractive index detector. The structure of the product was confirmed by ¹³C and ¹H NMR spectroscopy. Additional products like octyl diglucoside were also formed, the structure of which was confirmed by mass spectrometry.


Subject(s)
Biotechnology/methods , Glucosides/biosynthesis , Pichia/metabolism , beta-Glucosidase/metabolism , Biocatalysis , Cell Wall/metabolism , Chromatography, High Pressure Liquid , Culture Media/metabolism , Glucosides/metabolism , Magnetic Resonance Spectroscopy , Mass Spectrometry , Models, Biological
SELECTION OF CITATIONS
SEARCH DETAIL
...