Displaying publications 21 - 40 of 103 in total

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  1. Chilakamarry CR, Mahmood S, Saffe SNBM, Arifin MAB, Gupta A, Sikkandar MY, et al.
    3 Biotech, 2021 May;11(5):220.
    PMID: 33968565 DOI: 10.1007/s13205-021-02734-7
    Over recent years, keratin has gained great popularity due to its exceptional biocompatible and biodegradable nature. It has shown promising results in various industries like poultry, textile, agriculture, cosmetics, and pharmaceutical. Keratin is a multipurpose biopolymer that has been used in the production of fibrous composites, and with necessary modifications, it can be developed into gels, films, nanoparticles, and microparticles. Its stability against enzymatic degradation and unique biocompatibility has found their way into biomedical applications and regenerative medicine. This review discusses the structure of keratin, its classification and its properties. It also covers various methods by which keratin is extracted like chemical hydrolysis, enzymatic and microbial treatment, dissolution in ionic liquids, microwave irradiation, steam explosion technique, and thermal hydrolysis or superheated process. Special emphasis is placed on its utilisation in the form of hydrogels, films, fibres, sponges, and scaffolds in various biotechnological and industrial sectors. The present review can be noteworthy for the researchers working on natural protein and related usage.
  2. Uda MNA, Gopinath SCB, Hashim U, Halim NH, Parmin NA, Uda MNA, et al.
    3 Biotech, 2021 May;11(5):205.
    PMID: 33868892 DOI: 10.1007/s13205-021-02740-9
    This paper describes the synthesis of graphene-based activated carbon from carbonaceous rice straw fly ash in an electrical furnace and the subsequent potassium hydroxide extraction. The produced graphene has a proper morphological structure; flakes and a rough surface can be observed. The average size of the graphene was defined as up to 2000 nm and clarification was provided by high-resolution microscopes (FESEM and FETEM). Crystallinity was confirmed by surface area electron diffraction. The chemical bonding from the graphene was clearly observed, with -C=C- and O-H stretching at peaks of 1644 cm-1 and 3435 cm-1, respectively. Impurities in the graphene were found using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The measured size, according to zeta-potential analysis, was 8722.2 ± 25 nm, and the average polydispersity index was 0.576. The stability of the mass reduction was analyzed by a thermogravimetric at 100 °C, with a final reduction of ~ 11%.
  3. Gopinath SCB, Perumal V, Xuan S
    3 Biotech, 2020 Jun;10(6):270.
    PMID: 32523864 DOI: 10.1007/s13205-020-02261-x
    This study correlated and quantified the expression of microRNA-155 with breast cancer to determine breast cancer progression. The target microRNA-155 sequence was identified by complementation on a capture-probe sequence-immobilized interdigitated dual electrode surface. The sensitivity was found to be 1 fM, and the limit of detection fell between 1 and 10 fM. The specific sequence selectivity with single mismatches, triple mismatches, and noncomplementary bases failed to complement the capture-probe sequence. The obtained results demonstrate the selective determination of the microRNA-155 sequence and can help to diagnose breast cancer.
  4. Chuah R, Gopinath SCB, Anbu P, Salimi MN, Yaakub ARW, Lakshmipriya T
    3 Biotech, 2020 Aug;10(8):364.
    PMID: 32832325 DOI: 10.1007/s13205-020-02365-4
    In this study, biological deoxygenation of graphene oxide (GO) using an Eclipta prostrata phytoextract was performed via the infusion method. The presence of oxide groups on the surface of graphene and removal of oxides groups by reduction were characterized through morphological and structural analyses. Field emission scanning electron microscopy images revealed that the synthesized GO and rGO were smooth and morphologically sound. Transmission electron microscopy images showed rGO developing lattice fringes with smooth edges and transparent sheets. Atomic force microscopy images showed an increase in the surface roughness of graphite oxide (14.29 nm) compared with that of graphite (1.784 nm) due to the presence of oxide groups after oxidation, and the restoration of surface roughness to 2.051 nm upon reduction. Energy dispersive X-ray analysis indicated a difference in the carbon/oxygen ratio between GO (1.90) and rGO (2.70). Fourier-transform infrared spectroscopy spectrum revealed peak stretches at 1029, 1388, 1578, and 1630 cm-1 for GO, and a decrease in the peak intensity after reduction that confirmed the removal of oxide groups. X-ray photoelectron microscopy also showed a decrease in the intensity of oxygen peak after reduction. In addition, thermogravimetric analysis suggested that rGO was less thermally stable than graphite, graphite oxide, and GO, with rGO decomposing after heating at temperatures ranging from room temperature to 600 °C.
  5. Lai PJ, Ng EV, Yang SK, Moo CL, Low WY, Yap PS, et al.
    3 Biotech, 2020 Jul;10(7):313.
    PMID: 32596098 DOI: 10.1007/s13205-020-02304-3
    To better understand the synergistic antibacterial activity between piperacillin and Lavandula angustifolia essential oil (LEO) against multidrug-resistant Escherichia coli, we performed microarray transcriptomic analysis of LEO when used alone and in combination with piperacillin against the non-treated control. In total, 90 genes were differentially expressed after the combination of LEO and piperacillin treatment. Among the up-regulated genes, nfsB, nemA, fruA, nfsB, nemA are known to control microbial metabolism and nitrotoluene degradation, which were observed only in the LEO-piperacillin combinatory treatment. Four candidate genes from the microarray result, srIA, srID, waaR and nfsB, were validated by qRT-PCR as these genes showed differential expression consistently in the two methods. Biochemical pathway analysis showed that there was upregulation of genes involved in several biological processes including fructose and mannose metabolism, phosphotransferase system (PTS), lipopolysaccharide biosynthesis and nitrotoluene degradation. Genes involved in microbial metabolism in diverse environments were found both up- and down-regulated in LEO-piperacillin combinatory treatment. Our study provides new information concerning the transcriptional changes that occur during the LEO and piperacillin interaction against the multidrug-resistant bacteria and contributes to unravel the mechanisms underlying this synergism.
  6. Nakkarach A, Foo HL, Song AA, Nitisinprasert S, Withayagiat U
    3 Biotech, 2020 Jul;10(7):296.
    PMID: 32550113 DOI: 10.1007/s13205-020-02289-z
    Ingested dietary fibres are hydrolysed by colon microbiota to produce energy-providing short-chain fatty acids (SCFA) that stimulate anti-inflammatory effects. SCFA-producing bacteria were screened from bacteria isolated from human faeces using bromothymol blue as an acid indicator and gas chromatography for SCFA profiling. The beneficial functions (antagonistic activity, haemolytic activities, antibiotic susceptibility, mucus adherent percentage and toxin gene detection) were evaluated for the top five SCFA-producing bacteria isolated from three healthy volunteers that identified as Escherichia coli strains. They produced acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic acids at average concentrations of 15.9, 1.8, 1.1, 1.9, 1.8, 2.7 and 3.4 mM, respectively. The SCFA production by E. coli strains was rapidly increased during the first 8 h of incubation and gradually decreased after 16 h of incubation. All E. coli strains showed acid and bile tolerance, resulting in a survival rate greater than 70% with no haemolytic activity, mucus adherence greater than 40% and susceptibility to conventional antibiotics. Hence, the selected E. coli strains exhibited promising probiotic properties with neither enterotoxin nor LPS producibility was detected. The present results confirm the existence of friendly and harmless E. coli strains in human microbiota as potential probiotics.
  7. Shanmugapriya, Othman N, Sasidharan S
    3 Biotech, 2020 Sep;10(9):399.
    PMID: 32850286 DOI: 10.1007/s13205-020-02396-x
    The current study was conducted to validate the target proteins of down-regulated miR-221-5p in HeLa cells treated with P. longifolia leaf extract. The validation was done by label-free quantitative proteomics approaches, Gene Ontology (GO) and protein-protein interaction analyses after the cells transfected with miRNA mimics or miRNA inhibitor. The LC-ESI-MS/MS identified a total of 1061, 668, 564 and 940 proteins from untransfected and untreated HeLa cells, untransfected P. longifolia leaf extract-treated HeLa cells, miR-221-5p mimic-transfected P. longifolia leaf extract-treated HeLa cells and anti-miR-221-5p-transfected P. longifolia leaf extract-treated HeLa cells, respectively. The proteomic, GO and protein-protein interaction analyses showed that P. longifolia treatment regulated various protein expressions in HeLa cells, namely tropomyosin, PRKC apoptosis WT1 regulator protein (PAWR), alpha-enolase and beta-enolase, which induced apoptotic cell death after the down-regulation of miR-221-5p. Conclusively, this study showed P. longifolia leaf extract's vital contribution in regulating various protein expressions in HeLa cervical cancer cells to induce apoptotic cell death after downregulation miR-221-5p.
  8. Wang X, Gopinath SCB, Li J
    3 Biotech, 2020 Sep;10(9):377.
    PMID: 32802719 DOI: 10.1007/s13205-020-02370-7
    This work focused on the detection of cortisol on an interdigitated electrode sensor surface using an anti-cortisol antibody. To improve immobilization, antibodies were conjugated with silver nanoparticles and attached to the surface of the sensor. Cortisol interacted in a dose-dependent manner on the antibody-immobilized sensor surface, and current changes were observed. Linear regression analysis was performed by a 3σ calculation, and the limit of detection fell into the range of 0.01 and 0.1 ng/mL. The sensitivity of cortisol was calculated to be 0.01 ng/mL and the sensor discriminated against other hormones, namely norepinephrine and progesterone, with higher selectivity for cortisol. This result represented the selective detection of cortisol with high performance, which can help to determine anxiety disorders.
  9. Zaidi NS, Muda K, Sohaili J, Loan LW, Sillanpää M
    3 Biotech, 2020 Sep;10(9):408.
    PMID: 32904368 DOI: 10.1007/s13205-020-02398-9
    The aim of the present study is to investigate the potential of magnetic field application as an alternative approach for controlling sludge bulking due to long sludge retention time (SRT) while enhancing nitrification efficiency upon the occurrence. Two sequencing batch reactors, reactor A (SBRA, magnetic field intensity 88.0 mT) and reactor B (SBRB, control) were operated under long SRT to induce the growth of filamentous microorganisms. The effect of magnetic field on nitrification, viz. ammonia-nitrogen (NH4-N) and nitrite removal, as well as biomass properties were studied under the sludge bulking condition. Results indicated that nitrification efficiency of SBRA was consistently higher with 90% NH4-N removal and 74-81% nitrite removal, which could be credited to the enhanced biomass properties of activated sludge due to the induced magnetic field. Metabolism activity and biodegradability of aerobic bacteria were also enhanced through the application of magnetic field, even under long SRT condition. This was evidenced by the average oxygen uptake rate (OUR) in SBRA that was higher with 11.7 ± 1.2 mg/L·h compared to SBRB with 9.5 ± 0.4 mg/L·h. Occurrence of filamentous sludge bulking was likewise minimized.
  10. Yusof TY, Lian MQ, Ong EBB, Teh AH
    3 Biotech, 2021 Sep;11(9):409.
    PMID: 34471591 DOI: 10.1007/s13205-021-02955-w
    Yeast cell death is triggered when essential nutrients such as potassium and lipid are limited but ammonium is in excess. When ammonium and glucose were maintained at 100% of the normal concentration while all the other essential nutrients in yeast nitrogen base (YNB) were reduced to 2%, yeast growth was halted by ammonium toxicity. Yeast started to grow again when either ammonium was also reduced to 2% or gluconate was added, but simultaneously adding gluconate as well as reducing all the nutrients except glucose 50-fold revived yeast growth to a greater extent, i.e. a quarter of the normal growth. Gluconate, as well as formate and alginate, stimulated yeast growth by buffering the drop in pH. Yeast cells were seemingly more susceptible to low pH under the nutrient-limited conditions, entering the stationary phase at pH higher than that of the normal condition. Carboxylate salts may prove a cost-efficient replacement for large proportions of the essential nutrients as yeast cells, in the presence of 2 mg ml-1 gluconate, could still achieve nearly 90% of the normal growth when cultured in only 10% of the normal YNB concentration.
  11. Miao X, Wang F, Wang T, Razak SRA, Yunus MA, Ismail IS
    3 Biotech, 2021 Sep;11(9):423.
    PMID: 34603923 DOI: 10.1007/s13205-021-02971-w
    Long noncoding RNAs (lncRNAs) are implicated in various biological processes, such as cell proliferation, differentiation, apoptosis, migration, and invasion. They are also key players in various biological pathways. LncRNA was considered as 'translational noise' before 1980s. It has been reported that lncRNAs are aberrantly expressed in different cancers, either as oncogene or tumor suppressor gene. Therefore, more and more lncRNAs are recognized as potential diagnostic biomarkers and/or therapeutic targets. As competitive endogenous RNA, lncRNAs can interact with microRNA to alter the expression of target genes, which may have extensive clinical implications in cancers, including diagnosis, treatment, prognosis, and chemoresistance. This review comprehensively summarizes the functions and clinical relevance of lncRNAs in digestive system cancers, especially as a potential tool to overcome chemoresistance.
  12. Azami NA, Wirjon IA, Kannusamy S, Teh AH, Abdullah AA
    3 Biotech, 2017 May;7(1):75.
    PMID: 28452023 DOI: 10.1007/s13205-017-0716-7
    The contribution of microbial depolymerase has received much attention because of its potential in biopolymer degradation. In this study, the P(3HB) depolymerase enzyme of a newly isolated Burkholderia cepacia DP1 from soil in Penang, Malaysia, was optimized using response surface methodology (RSM). The factors affecting P(3HB) depolymerase enzyme production were studied using one-variable-at-a-time approach prior to optimization. Preliminary experiments revealed that the concentration of nitrogen source, concentration of carbon source, initial pH and incubation time were among the main factors influencing the enzyme productivity. An increase of 9.4 folds in enzyme production with an activity of 5.66 U/mL was obtained using optimal medium containing 0.028% N of di-ammonium hydrogen phosphate and 0.31% P(3HB-co-21%4HB) as carbon source at the initial pH of 6.8 for 38 h of incubation. Moreover, the RSM model showed great similarity between predicted and actual enzyme production indicating a successful model validation. This study warrants the ability of P(3HB) degradation by B. cepacia DP1 in producing higher enzyme activity as compared to other P(3HB) degraders being reported. Interestingly, the production of P(3HB) depolymerase was rarely reported within genus Burkholderia. Therefore, this is considered to be a new discovery in the field of P(3HB) depolymerase production.
  13. Haque M, Islam SMS, Subramaniam S
    3 Biotech, 2017 May;7(1):63.
    PMID: 28452013 DOI: 10.1007/s13205-017-0675-z
    An efficient callus induction and plant regeneration system has been developed using salt and heat as pre-treatment factors for three barley genotypes viz. BB-3, BB-6 and BHL-18. Different concentrations of NaCl (1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 g/L) were used and its effects were determined on the basis of the viability of callus (CV), plant regeneration (PR), relative growth rate (RGR) and tolerance index (TI). The BB-6 showed highest performance on tolerance based on CV (14.72%), PR (7.69%), RGR (0.91%) and TI (0.42%) at 6.5 g/L NaCl. Various NaCl concentrations displayed significantly differences at P 
  14. Elgharbawy AA, Alam MZ, Moniruzzaman M, Kabbashi NA, Jamal P
    3 Biotech, 2018 May;8(5):236.
    PMID: 29744268 DOI: 10.1007/s13205-018-1253-8
    The pretreatment of empty fruit bunch (EFB) was conducted using an integrated system of IL and cellulases (IL-E), with simultaneous fermentation in one vessel. The cellulase mixture (PKC-Cel) was derived from Trichoderma reesei by solid-state fermentation. Choline acetate [Cho]OAc was utilized for the pretreatment due to its biocompatibility and biodegradability. The treated EFB and its hydrolysate were characterized by the Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis. The results showed that there were significant structural changes in EFB after the treatment in IL-E system. The sugar yield after enzymatic hydrolysis by the PKC-Cel was increased from 0.058 g/g of EFB in the crude sample (untreated) to 0.283 and 0.62 ± 06 g/g in IL-E system after 24 and 48 h of treatment, respectively. The EFB hydrolysate showed the eligibility for ethanol production without any supplements where ethanol yield was 0.275 g ethanol/g EFB in the presence of the IL, while lower yield obtained without IL-pretreatment. Moreover, it was demonstrated that furfural and phenolic compounds were not at the level of suppressing the fermentation process.
  15. Karim KMR, Husaini A, Sing NN, Sinang FM, Roslan HA, Hussain H
    3 Biotech, 2018 Apr;8(4):204.
    PMID: 29607285 DOI: 10.1007/s13205-018-1225-z
    In this study, an alpha-amylase enzyme from a locally isolated Aspergillus flavus NSH9 was purified and characterized. The extracellular α-amylase was purified by ammonium sulfate precipitation and anion-exchange chromatography at a final yield of 2.55-fold and recovery of 11.73%. The molecular mass of the purified α-amylase was estimated to be 54 kDa using SDS-PAGE and the enzyme exhibited optimal catalytic activity at pH 5.0 and temperature of 50 °C. The enzyme was also thermally stable at 50 °C, with 87% residual activity after 60 min. As a metalloenzymes containing calcium, the purified α-amylase showed significantly increased enzyme activity in the presence of Ca2+ ions. Further gene isolation and characterization shows that the α-amylase gene of A. flavus NSH9 contained eight introns and an open reading frame that encodes for 499 amino acids with the first 21 amino acids presumed to be a signal peptide. Analysis of the deduced peptide sequence showed the presence of three conserved catalytic residues of α-amylase, two Ca2+-binding sites, seven conserved peptide sequences, and several other properties that indicates the protein belongs to glycosyl hydrolase family 13 capable of acting on α-1,4-bonds only. Based on sequence similarity, the deduced peptide sequence of A. flavus NSH9 α-amylase was also found to carry two potential surface/secondary-binding site (SBS) residues (Trp 237 and Tyr 409) that might be playing crucial roles in both the enzyme activity and also the binding of starch granules.
  16. Mohamad Ikubar MR, Abdul Manan M, Md Salleh M, Yahya A
    3 Biotech, 2018 May;8(5):259.
    PMID: 29765817 DOI: 10.1007/s13205-018-1268-1
    In current practice, oil palm frond leaflets and stems are re-used for soil nutrient recycling, while the petioles are typically burned. Frond petioles have high commercialization value, attributed to high lignocellulose fiber content and abundant of juice containing free reducing sugars. Pressed petiole fiber is the subject of interest in this study for the production of lignocellulolytic enzyme. The initial characterization showed the combination of 0.125 mm frond particle size and 60% moisture content provided a surface area of 42.3 m2/g, porosity of 12.8%, and density of 1.2 g/cm3, which facilitated fungal solid-state fermentation. Among the several species of Aspergillus and Trichoderma tested, Aspergillus awamori MMS4 yielded the highest xylanase (109 IU/g) and cellulase (12 IU/g), while Trichoderma virens UKM1 yielded the highest lignin peroxidase (222 IU/g). Crude enzyme cocktail also contained various sugar residues, mainly glucose and xylose (0.1-0.4 g/L), from the hydrolysis of cellulose and hemicellulose. FT-IR analysis of the fermented petioles observed reduction in cellulose crystallinity (I900/1098), cellulose-lignin (I900/1511), and lignin-hemicellulose (I1511/1738) linkages. The study demonstrated successful bioconversion of chemically untreated frond petioles into lignin peroxidase and xylanase-rich enzyme cocktail under SSF condition.
  17. Kamarudin NB, Sharma S, Gupta A, Kee CG, Chik SMSBT, Gupta R
    3 Biotech, 2017 Jun;7(2):127.
    PMID: 28573397 DOI: 10.1007/s13205-017-0767-9
    Uncontrolled disposal of feathers from the poultry industry and slaughterhouses is environmentally undesirable. The feathers are composed of approximately 90% of keratin which is an important ingredient of cosmetics, shampoos and hair treatment creams. This study aimed to determine the optimum conditions for the extraction of keratin from chicken feathers. The extraction of keratin using various reducing agents was studied using statistical experimental design. In the extraction process, pH, temperature, ratio of reducing agents, mass of chicken feathers and incubation time were analyzed. The keratin in the total extracted protein was purified by size exclusion chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and further characterized using amino acids profile analysis. The surface morphology and chemical composition were studied by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. Sodium sulfide (Na2S) yielded 84.5% of keratin as compared to sodium hydroxide (43.8), urea mixture (50.6), mixture of sodium dodecyl sulfate (SDS) and sodium bisulfite (18.3) and a mixture of Na2S and sodium hydroxide (41.5%) under optimized conditions. The optimum yield of keratin was achieved at 80.9 °C in 9.5 h with 0.05 M sodium sulfide using response surface methodology (RSM). Among the five parameters screened, pH was found not to be significant because the p value was greater than 0.05.
  18. Nur Asshifa MN, Zambry NS, Salwa MS, Yahya ARM
    3 Biotech, 2017 Jul;7(3):189.
    PMID: 28664380 DOI: 10.1007/s13205-017-0828-0
    Water-immiscible substrate, diesel, was supplied as the main substrate in the fermentation of Pseudomonas aeruginosa USM-AR2 producing rhamnolipid biosurfactant, in a stirred tank bioreactor. In addition to the typical gas-aqueous system, this system includes gas-hydrocarbon-aqueous phases and the presence of surfactant (rhamnolipid) in the fermentation broth. The effect of diesel dispersion on volumetric oxygen transfer coefficient, k L a, and thus oxygen transfer, was evaluated at different agitations of 400, 500 and 600 rpm. The oxygen transfer in this oil-water-surfactant system was shown to be affected by different oil dispersion at those agitation rates. The highest diesel dispersion was obtained at 500 rpm or impeller tip speed of 1.31 m/s, compared to 400 and 600 rpm, which led to the highest k L a, growth and rhamnolipid production by P. aeruginosa USM-AR2. This showed the highest substrate mixing and homogenization at this agitation speed that led to the efficient substrate utilization by the cells. The oxygen uptake rate of P. aeruginosa USM-AR2 was 5.55 mmol/L/h, which showed that even the lowest k L a (48.21 h-1) and hence OTR (57.71 mmol/L/h) obtained at 400 rpm was sufficient to fulfill the oxygen demand of the cells. The effect of rhamnolipid concentration on k L a showed that k L a increased as rhamnolipid concentration increased to 0.6 g/L before reaching a plateau. This trend was similar for all agitation rates of 400, 500 and 600 rpm, which might be due to the increase in the resistance to oxygen transfer (k L decrease) and the increase in the specific interfacial area (a).
  19. Ang TF, Salleh AB, Normi YM, Leow TC
    3 Biotech, 2018 Jul;8(7):314.
    PMID: 30023146 DOI: 10.1007/s13205-018-1333-9
    Artificial metalloenzymes are unique as they combine the good features of homogeneous and enzymatic catalysts, and they can potentially improve some difficult catalytic assays. This study reports a method that can be used to create an artificial metal-binding site prior to proving it to be functional in a wet lab. Haloalkane dehalogenase was grafted into a metal-binding site to form an artificial metallo-haloalkane dehalogenase and was studied for its potential functionalities in silico. Computational protocols regarding dynamic metal docking were studied using native metalloenzymes and functional artificial metalloenzymes. Using YASARA Structure, a simulation box covering template structure was created to be filled with water molecules followed by one mutated water molecule closest to the metal-binding site to metal ion. A simple energy minimization step was subsequently run using an AMBER force field to allow the metal ion to interact with the metal-binding residues. Long molecular dynamic simulation using YASARA Structure was performed to analyze the stability of the metal-binding site and the distance between metal-binding residues. Metal ions fluctuating around 2.0 Å across a 20 ns simulation indicated a stable metal-binding site. Metal-binding energies were predicted using FoldX, with a native metalloenzyme (carbonic anhydrase) scoring 18.0 kcal/mol and the best mutant model (C1a) scoring 16.4 kcal/mol. Analysis of the metal-binding site geometry was performed using CheckMyMetal, and all scores for the metalloenzymes and mutant models were in an acceptable range. Like native metalloenzymes, the metal-binding site of C1a was supported by residues in the second coordination shell to maintain a more coordinated metal-binding site. Short-chain multihalogenated alkanes (1,2-dibromoethane and 1,2,3-trichloropropane) were able to dock in the active site of C1a. The halides of the substrate were in contact with both the metal and halide-stabilizing residues, thus indicating a better stabilization of the substrate. The simple catalytic mechanism proposed is that the metal ion interacted with halogen and polarized the carbon-halogen bond, thus making the alpha carbon susceptible to attack by nucleophilic hydroxide. The interaction between halogen in the metal ion and halide-stabilizing residues may help to improve the stabilization of the substrate-enzyme complex and reduce the activation energy. This study reports a modified dynamic metal-docking protocol and validation tests to verify the metal-binding site. These approaches can be applied to design different kinds of artificial metalloenzymes or metal-binding sites.
  20. Jamil SZMR, Rohani ER, Baharum SN, Noor NM
    3 Biotech, 2018 Aug;8(8):322.
    PMID: 30034986 DOI: 10.1007/s13205-018-1336-6
    Callus was induced from mangosteen (Garcinia mangostana L.) young purple-red leaves on Murashige and Skoog basal medium with various combinations of plant growth regulators. Murashige and Skoog medium with 4.44 µM 6-benzylaminopurine and 4.52 µM 2,4-dichlorophenoxyacetic acid was the best for friable callus induction. This friable callus was used for the initiation of cell suspension culture. The effects of different combinations of 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid, carbon sources and inoculum sizes were tested. It was found that combination of 2.22 µM 6-benzylaminopurine + 2.26 µM 2,4-dichlorophenoxyacetic acid, glucose (30 g/l) and 1.5 g/50 ml inoculum size was the best for cell growth. Callus and cell suspension cultures were then treated either with 100 µM methyl jasmonate as an elicitor for 5 days, or 0.5 g/l casein hydrolysate as an organic supplement for 7 days. Metabolites were then extracted and profiled using liquid chromatography-time of flight mass spectrometry. Multivariate discriminant analyses revealed significant metabolite differences (P ≤ 0.05) for callus and suspension cells treated either with methyl jasmonate or casein hydrolysate. Based on MS/MS data, methyl jasmonate stimulated the production of an alkaloid (thalsimine) and fatty acid (phosphatidyl ethanolamine) in suspension cells while in callus, an alkaloid (thiacremonone) and glucosinolate (7-methylthioheptanaldoxime) was produced. Meanwhile casein hydrolysate stimulated the production of alkaloids such as 3ß,6ß-dihydroxynortropane and cis-hinokiresinol and triterpenoids such as schidigerasaponin and talinumoside in suspension cells. This study provides evidence on the potential of secondary metabolite production from in vitro culture of mangosteen.
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