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Investigations on the interactions of proteins with nanocellulose produced via sulphuric acid hydrolysis

Gunathilake TMSU, Ching YC, Uyama H, Nguyen DH, Chuah CH

Int J Biol Macromol, 2021 Dec 15;193(Pt B):1522-1531.
PMID: 34740692 DOI: 10.1016/j.ijbiomac.2021.10.215

The investigation of protein-nanoparticle interactions contributes to the understanding of nanoparticle bio-reactivity and creates a database of nanoparticles for use in nanomedicine, nanodiagnosis, and nanotherapy. In this study, hen's egg white was used as the protein source to study the interaction of proteins with sulphuric acid hydrolysed nanocellulose (CNC). Several techniques such as FTIR, zeta potential measurement, UV-vis spectroscopy, compressive strength, TGA, contact angle and FESEM provide valuable information in the protein-CNC interaction study. The presence of a broader peak in the 1600-1050 cm-1 range of CNC/egg white protein FTIR spectrum compared to the 1600-1050 cm-1 range of CNC sample indicated the binding of egg white protein to CNC surface. The contact angle with the glass surface decreased with the addition of CNC to egg white protein. The FESEM EDX spectra showed a higher amount of N and Na on the surface of CNC. It indicates the density of protein molecules higher around CNC. The zeta potential of CNC changed from -26.7 ± 0.46 to -21.7 ± 0.2 with the introduction of egg white protein due to the hydrogen bonding, polar bonds and electrostatic interaction between surface CNC and protein. The compressive strength of the egg white protein films increased from 0.064 ± 0.01 to 0.36 ± 0.02 MPa with increasing the CNC concentration from 0 to 4.73% (w/v). The thermal decomposition temperature of CNC/egg white protein decreased compared to egg white protein thermal decomposition temperature. According to UV-Vis spectroscopy, the far-UV light (207-222nm) absorption peak slightly changed in the CNC/egg white protein spectrum compared to the egg white protein spectrum. Based on the results, the observations of protein nanoparticle interactions provide an additional understanding, besides the theoretical simulations from previous studies. Also, the results indicate to aim CNC for the application of nanomedicine and nanotherapy. A new insight given by us in this research assumes a reasonable solution to these crucial applications.

Matched MeSH terms: Cellulose/chemistry*; Proteins/chemistry*; Sulfuric Acids/chemistry*; Nanoparticles/chemistry*
GC-MS Analysis of Bioactive Compounds in Ethanolic Leaf Extract of Hellenia speciosa (J.Koenig) S.R. Dutta

R R

Appl Biochem Biotechnol, 2022 Jan;194(1):176-186.
PMID: 34762268 DOI: 10.1007/s12010-021-03742-2

Hellenia speciosa (J.Koenig) S.R. Dutta is a plant species belonging to the family Costaceae. It is widely distributed in China, India, Malaysia, Indonesia, tropical, and subtropical Asia. In Ayurveda, the rhizome of this plant has been extensively used to treat fever, rash, asthma, bronchitis, and intestinal worms. The objective of the present study was to investigate the phytochemical constituents of the leaf of Hellenia speciosa using gas chromatography and mass spectroscopy analysis (GC-MS). The GC-MS analysis revealed the presence of 17 phytochemical components in the ethanolic leaf extract of Hellenia speciosa. The prevailing bioactive compounds present in Hellenia speciosa were thymol (RT-10.019; 3.59%), caryophyllene (RT-11.854; 0.62%), caryophyllene oxide (RT-13.919; 1.34%), artumerone (RT-14.795; 1.35%), hexadecanoic acid methyl ester (RT-17.536; 2.77%), 9,12-octadecanoic acid methyl ester (RT-19.163; 1.35%), squalene (RT-24.980; 1.19%), piperine (RT-25.745; 3.11%), beta tocopherol (RT-26.681; 2.88%), vitamin E (RT-27.290; 2.64%), progesterone (RT-29.608; 3.18%), caparratriene (RT-29.861; 9.72%), and testosterone (RT-30.73; 5.81%). The compounds were identified by comparing their retention time and peak area with that of the literature and by interpretation of mass spectra. The results and findings of the present study suggest that the plant leaf can be used as a valuable source in the field of herbal drug discovery. The presence of bioactive compounds justifies the use of plant leaves for treating various diseases with fewer side effects and recommended the plant of pharmaceutical importance. However, further studies are needed to undertake its bioactivity and toxicity profile.

Matched MeSH terms: Ethanol/chemistry*; Plant Extracts/chemistry*; Plant Leaves/chemistry*; Zingiberales/chemistry*
Investigation on Secondary Structure Perturbations of Proteins Embedded in Solid Lipid Matrices as a Novel Indicator of their Biological Activity upon In Vitro Release

Zeeshan F, Tabbassum M, Jorgensen L, Medlicott NJ

AAPS PharmSciTech, 2018 Feb;19(2):769-782.
PMID: 29134579 DOI: 10.1208/s12249-017-0883-1

Protein biologics are prone to conformational changes during formulation development. Limited methods are available for conformational analysis of proteins in solid state and in the presences of formulation excipients. The aim of this study was to investigate the secondary structures of proteins encased in solid lipid matrices as a novel indicator of their stability upon in vitro release. Model proteins namely catalase and lysozyme were incorporated into lipid namely Precirol® AT05 (glycerol palmitostearate, melting point 58°C) at 30% w/w loading using melting and mixing and wet granulation methods. Attenuated total reflectance (ATR-FTIR) spectroscopy, size-exclusion chromatography (SEC) and biological activity analyses were performed. The information about secondary structure was acquired using second derivative analysis of amide-I band (1600-1700 cm-1). ATR analysis demonstrated interference of lipid spectrum with protein amide-I band which was subsequently subtracted to allow the analysis of the secondary structure. ATR spectra amide-I bands showed shifts peak band positions compared to native protein for matrices prepared using wet granulation. SEC analysis gave evidence of protein aggregation for catalase which was increased using wet granulation. The biological activity of catalase was statistically different from that of control and was affected by the incorporation method and was found to be in alignment with ATR spectral changes and extent of aggregation. In conclusion, ATR spectroscopy could analyze protein secondary structure in lipid matrices provided lipid interference was minimized. The ATR spectral changes and formation of aggregates can indicate the loss in biological activity of protein released from solid lipid matrices.

Matched MeSH terms: Catalase/chemistry; Diglycerides/chemistry; Excipients/chemistry; Muramidase/chemistry
The effect of chewing simulation on surface roughness of resin composite when opposed by zirconia ceramic and lithium disilicate ceramic

Ho TK, Satterthwaite JD, Silikas N

Dent Mater, 2018 02;34(2):e15-e24.
PMID: 29175160 DOI: 10.1016/j.dental.2017.11.014

OBJECTIVE: To assess the change in surface roughness of nanohybrid resin composite (Tetric EvoCeram) after antagonist wear against monolithic zirconia and lithium disilicate ceramics through a simulated chewing test using a three-dimensional (3D) profilometer.
METHODS: A total of 40 Tetric EvoCeram™ resin composite specimens against either a Lava™ Plus zirconia antagonist (n=20) or IPS e.max Press lithium disilicate antagonist (n=20) were prepared for the study. The surface roughness profiles of each resin composite before and after an in-vitro simulated chewing test were analysed using a 3D profilometer and Talymap software. After the simulated chewing, the surface profiles of representative Tetric EvoCeram specimens from each group were analysed using scanning electron microscopy. Independent t-test and paired t-test were used for statistical analysis.
RESULTS: For both lithium disilicate and zirconia groups, all surface roughness parameters (Ra, Rt, Sa, Sq,) of Tetric EvoCeram were significantly higher post-chewing compared to pre-chewing (p<0.05); the post-chewing surface roughness parameters of Tetric EvoCeram for the lithium disilicate group were significantly higher (p<0.05) than in the zirconia group.
SIGNIFICANCE: This chewing simulation test showed that Tetric EvoCeram composites exhibited a rougher surface when opposing lithium disilicate ceramic compared to opposing zirconia ceramic.

Matched MeSH terms: Composite Resins/chemistry*; Dental Materials/chemistry*; Dental Porcelain/chemistry*; Zirconium/chemistry*
Potential of porous Co3O4 nanorods as cathode catalyst for oxygen reduction reaction in microbial fuel cells

Kumar R, Singh L, Zularisam AW, Hai FI

Bioresour Technol, 2016 Nov;220:537-542.
PMID: 27614156 DOI: 10.1016/j.biortech.2016.09.003

This study aims to investigate the potential of porous Co3O4 nanorods as the cathode catalyst for oxygen reduction reaction (ORR) in aqueous air cathode microbial fuel cells (MFCs). The porous Co3O4 nanorods were synthesized by a facile and cost-effective hydrothermal method. Three different concentrations (0.5mg/cm(2), 1mg/cm(2), and 2mg/cm(2)) of Co3O4 nanorods coated on graphite electrodes were used to test its performance in MFCs. The results showed that the addition of porous Co3O4 nanorods enhanced the electrocatalytic activity and ORR kinetics significantly and the overall resistance of the system was greatly reduced. Moreover, the MFC with a higher concentration of the catalyst achieved a maximum power density of 503±16mW/m(2), which was approximately five times higher than the bare graphite electrode. The improved catalytic activity of the cathodes could be due to the porous properties of Co3O4 nanorods that provided the higher number of active sites for oxygen.

Matched MeSH terms: Cobalt/chemistry*; Electrochemistry; Oxides/chemistry*; Oxygen/chemistry*; Nanotubes/chemistry*
Unusual phenethylamine-containing alkaloids from Elaeocarpus tectorius

Ezeoke MC, Krishnan P, Sim DS, Lim SH, Low YY, Chong KW, et al.

Phytochemistry, 2018 Feb;146:75-81.
PMID: 29247894 DOI: 10.1016/j.phytochem.2017.12.003

From the leaves of Elaeocarpus tectorius (Lour.) Poir. four previously undescribed phenethylamine-containing alkaloids were isolated, namely, tectoricine, possessing an unprecedented isoquinuclidinone ring system incorporating a phenethylamine moiety, tectoraline, representing a rare alkamide incorporating two phenethylamine moieties, and tectoramidines A and B, representing the first naturally occurring trimeric and dimeric phenethylamine alkaloids incorporating an amidine function. The structures of these alkaloids were established by detailed spectroscopic analysis. The absolute configuration of tectoricine was determined by comparison of the experimental and calculated ECD spectra. Plausible biosynthetic pathways to the four alkaloids are proposed.

Matched MeSH terms: Alkaloids/chemistry*; Phenethylamines/chemistry*; Plant Leaves/chemistry; Elaeocarpaceae/chemistry*
In vitro selection and characterization of single stranded DNA aptamers for luteolin: A possible recognition tool

Tuma Sabah J, Zulkifli RM, Shahir S, Ahmed F, Abdul Kadir MR, Zakaria Z

Anal Biochem, 2018 05 15;549:72-79.
PMID: 29524380 DOI: 10.1016/j.ab.2018.03.004

Distinctive bioactivities possessed by luteolin (3', 4', 5, 7-tetrahydroxy-flavone) are advantageous for sundry practical applications. This paper reports the in vitro selection and characterization of single stranded-DNA (ssDNA) aptamers, specific for luteolin (LUT). 76-mer library containing 1015 randomized ssDNA were screened via systematic evolution of ligands by exponential enrichment (SELEX). The recovered ssDNA pool from the 8th round was amplified with unlabeled primers and cloned into PSTBlue-1 vector prior to sequencing. 22 of LUT-binding aptamer variants were further classified into one of the seven groups based on their N40 random sequence regions, wherein one representative from each group was characterized. The dissociation constant of aptamers designated as LUT#28, LUT#20 and LUT#3 was discerned to be 107, 214 and 109 nM, respectively with high binding affinity towards LUT. Prediction analysis of the secondary structure suggested discrete features with typical loop and stem motifs. Furthermore, LUT#3 displayed higher specificity with insignificant binding toward kaempferol and quercetin despite its structural and functional similarity compared to LUT#28 and LUT#20. Further LUT#3 can detect free luteolin within 0.2-1 mM in solution. It was suggested that LUT#3 aptamer were the most suitable for LUT recognition tool at laboratory scale based on the condition tested.

Matched MeSH terms: Quercetin/chemistry*; Kaempferols/chemistry*; Luteolin/chemistry*; Aptamers, Nucleotide/chemistry
Fulltext Biochemical analysis of collagens from the bone of lizardfish (Saurida tumbil Bloch, 1795) extracted with different acids

Jaziri AA, Shapawi R, Mohd Mokhtar RA, Md Noordin WN, Huda N

PeerJ, 2022;10:e13103.
PMID: 35310170 DOI: 10.7717/peerj.13103

BACKGROUND: Lizardfish (Saurida tumbil Bloch, 1795) bone is a fish by-product generated during industrial surimi processing. This by-product is an important source of collagen production since the use of terrestrial animal-based collagens no longer sought due to concern regarding the transfer of infectious diseases and religious issues. Hence, this study was carried out to determine the biochemical analysis of collagens from the bone of lizardfish extracted with different acids.
METHODS: Lizardfish bone collagens were extracted with various acids (i.e., acetic, lactic and citric acids). All extraction processes were conducted in a chiller room (4 °C). The extracted collagens were biochemically characterized, such as hydroxyproline content, Ultraviolet (UV) absorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy spectra (FTIR), Differential scanning calorimetry (DSC) and solubility in different pH values and NaCl concentrations.
RESULTS: The yield of extracted collagens ranged between 1.73% and 2.59%, with the highest (p

Matched MeSH terms: Acids/chemistry; Collagen/chemistry; Acetic Acid/chemistry; Collagen Type I/chemistry
Comparative phytochemical composition, oleuropein quantification, antioxidant and cytotoxic properties of Olea europaea L. leaves

Anwar S, Saleem H, Khurshid U, Ansari SY, Alghamdi S, Al-Khulaidi AWA, et al.

Nat Prod Res, 2023 Mar;37(6):1023-1029.
PMID: 35815778 DOI: 10.1080/14786419.2022.2097230

In the present research, oleuropein (OLE) contents from two Saudi Arabian wild olive trees (Olea europaea L.) leaves (O1 and O2), were collected from two nearby geographical sites differing in altitudes, and were determined via UHPLC-MS analysis. Moreover, total bioactive contents, antioxidant, and cytotoxicity (against MCF-7 and MDA-MB-231 cells) potential were also evaluated. The sample (O2) was found to contain significantly (p

Matched MeSH terms: Antioxidants/chemistry; Plant Extracts/chemistry; Plant Leaves/chemistry; Iridoids/chemistry
Investigation of ethyl lactate as a green solvent for desorption of total petroleum hydrocarbons (TPH) from contaminated soil

Jalilian Ahmadkalaei SP, Gan S, Ng HK, Abdul Talib S

Environ Sci Pollut Res Int, 2016 Nov;23(21):22008-22018.
PMID: 27539472

Treatment of oil-contaminated soil is a major environmental concern worldwide. The aim of this study is to examine the applicability of a green solvent, ethyl lactate (EL), in desorption of diesel aliphatic fraction within total petroleum hydrocarbons (TPH) in contaminated soil and to determine the associated desorption kinetics. Batch desorption experiments were carried out on artificially contaminated soil at different EL solvent percentages (%). In analysing the diesel range of TPH, TPH was divided into three fractions and the effect of solvent extraction on each fraction was examined. The experimental results demonstrated that EL has a high and fast desorbing power. Pseudo-second order rate equation described the experimental desorption kinetics data well with correlation coefficient values, R (2), between 0.9219 and 0.9999. The effects of EL percentage, initial contamination level of soil and liquid to solid ratio (L/S (v/w)) on initial desorption rate have also been evaluated. The effective desorption performance of ethyl lactate shows its potential as a removal agent for remediation of TPH-contaminated soil worldwide.

Matched MeSH terms: Hydrocarbons/chemistry*; Lactates/chemistry*; Soil Pollutants/chemistry*; Solvents/chemistry
Controlled acid catalyzed sol gel for the synthesis of highly active TiO2-chitosan nanocomposite and its corresponding photocatalytic activity

Afzal S, Samsudin EM, Julkapli NM, Hamid SB

Environ Sci Pollut Res Int, 2016 Nov;23(22):23158-23168.
PMID: 27591888

For the synthesis of a highly active TiO2-chitosan nanocomposite, pH plays a crucial role towards controlling its morphology, size, crystallinity, thermal stability, and surface adsorption properties. The presence of chitosan (CS) biopolymer facilitates greater sustainability to the photoexcited electrons and holes on the catalysts' surface. The variation of synthesis pH from 2 to 5 resulted in different physico-chemical and photocatalytic properties, whereby a pH of 3 resulted in TiO2-chitosan nanocomposite with the highest photocatalytic degradation (above 99 %) of methylene orange (MO) dye. This was attributed to the efficient surface absorption properties, high crystallinity, and the presence of reactive surfaces of -NH2 and -OH groups, which enhances the adsorption-photodegradation effect. The larger surface oxygen vacancies coupled with reduced electron-hole recombination further enhanced the photocatalytic activity. It is undeniable that the pH during synthesis is critical towards the development of the properties of the TiO2-chitosan nanocomposite for the enhancement of photocatalytic activity.

Matched MeSH terms: Acids/chemistry; Titanium/chemistry*; Chitosan/chemistry*; Nanocomposites/chemistry*
Effects of production conditions on yield and physicochemical properties of biochars produced from rice husk and oil palm empty fruit bunches

Yavari S, Malakahmad A, Sapari NB

Environ Sci Pollut Res Int, 2016 Sep;23(18):17928-40.
PMID: 27255313 DOI: 10.1007/s11356-016-6943-3

Biochar is the bio-solid material produced by pyrolysis. The biochar properties are controlled by feedstock and pyrolysis variables. In this study, the impacts of these production variables on biochar yield and physicochemical properties including pH, cation exchange capacity (CEC), total organic carbon (TOC) content, surface area, and pore volume and size were investigated. Rice husk (RH) and oil palm empty fruit bunches (EFB) were used as biomass. The biochars were produced at temperature range of 300 to 700 °C, heating rate of 3 to 10 °C/min and retention time of 1 to 3 h. The pyrolysis conditions were optimized using response surface methodology (RSM) technique to maximize the values of the responses. Analysis of variance (ANOVA) of the results demonstrated that the data fitted well to the linear and quadratic equations. Temperature was found to be the most effective parameter on the responses followed by retention time and heating rate, sequentially. CEC, TOC, surface area, and pore characteristics were evaluated as biochar properties determining their sorption potential. The optimum conditions for the maximum values of the properties were temperatures of 700 and 493.44 °C and time of 3 and 1 h for RH and EFB biochars, respectively. Heating rate at 3 °C/min was found to be the best rate for both biochars. The structure of EFB biomass was more sensitive to heating than rice husk. The biomass type and the production variables were demonstrated as the direct effective factors on biochar yield and physicochemical properties.

Matched MeSH terms: Charcoal/chemistry*; Fruit/chemistry*; Plant Oils/chemistry*; Oryza/chemistry*
Distributions and source apportionment of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in rivers and estuaries of Peninsular Malaysia

Keshavarzifard M, Zakaria MP, Hwai TS, Yusuff FM, Mustafa S

Environ Sci Pollut Res Int, 2015 Jun;22(12):9424-37.
PMID: 25604562 DOI: 10.1007/s11356-015-4093-7

In this study, the distributions and sources of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in the Malaysian rivers and estuaries were evaluated. The concentrations of 16 USEPA PAHs varied from 225.5 to 293.9 (Perlis River), 195.2 to 481.2 (Kedah River), 791.2 to 1995.4 (Merbok River), 231.2 to 426.7 (Perak River), and 3803.2 to 7442.7 ng g(-1) (Klang River) dry weight. PAHs can be classified as moderate in the Perlis, Kedah, and Perak Rivers, moderate to high in the Merbok River, and high to very high in the Klang River. The comparison of PAHs with sediment quality guidelines (SQGs) indicates that occasionally adverse biological effects may occur from total PAHs, low molecular weight (LMW), and high molecular weight (HMW) PAHs at stations 1, 2, and 3 of the Klang River and from total PAHs at station 2 of the Merbok River. The diagnostic ratios of individual PAHs indicate both petrogenic and pyrogenic origin PAHs with significant dominance of pyrogenic sources in the study areas. The results suggest that Malaysian sediments had hopane ratios (C29/C30) similar to MECO suggesting MECO as a major source of the petroleum hydrocarbons found in the sediments, which is consistent with results reported in previous studies. These findings demonstrate that effective and improved environmental regulations in Malaysia have shifted the source of petroleum hydrocarbons from petrogenic to pyrogenic origin.

Matched MeSH terms: Polycyclic Hydrocarbons, Aromatic/chemistry*; Triterpenes/chemistry*; Water Pollutants, Chemical/chemistry*; Rivers/chemistry*
Lignocellulosic biomass supported metal nanoparticles for the catalytic reduction of organic pollutants

Akhtar K, Ali F, Sohni S, Kamal T, Asiri AM, Bakhsh EM, et al.

Environ Sci Pollut Res Int, 2020 Jan;27(1):823-836.
PMID: 31811610 DOI: 10.1007/s11356-019-06908-y

Lignocellulosic biomass waste is a cheap, eco-friendly, and sustainable raw material for a wide array of applications. In the present study, an easy, fast, and economically feasible route has been proposed for the preparation of different zero-valent metal nanoparticles (ZV-MNPs) based on Cu, Co, Ag, and Ni NPs using empty fruit bunch (EFB) biomass residue as support material. The catalytic efficiency of ZV-MNPs/EFB catalyst was investigated against five model pollutants, such as methyl orange (MO), congo red (CR), methylene blue (MB), acridine orange (AO), and 4-nitrophenol (4-NP) using NaBH4 as a source of hydrogen and electron. Comparative study revealed that among as-prepared ZV-MNPs/EFB catalysts, Cu-NPs immobilized onto EFB (Cu/EFB) exhibited maximum catalytic efficiency towards pollutant abasement. Degradation reactions were highly efficient, and were completed within a short time (4 min) in case of MO, CR, and MB, whilst AO and 4-NP were reduced in less than 15 min. Kinetic investigation revealed that the degradation rate of model pollutants accorded with pseudo-first order model. Furthermore, supported catalysts were easily recovered after the completion of experiment by simply pulling the catalyst from reaction system. Recyclability tests performed on Cu/EFB revealed that more than 97% of the reduction was achieved in case of MO dye for four successive cycles of reuse. The as-prepared heterostructure showed multifunctional properties, such as enhanced uptake of contaminants, high catalytic efficiency, and easy recovery, hence, offers great prospects in wastewater purification.

Matched MeSH terms: Congo Red/chemistry; Environmental Pollutants/chemistry*; Lignin/chemistry*; Metal Nanoparticles/chemistry*
Carboxymethyl cellulose/sodium alginate beads incorporated with calcium carbonate nanoparticles and bentonite for phosphate recovery

Fu J, Yap JX, Leo CP, Chang CK

Int J Biol Macromol, 2023 Apr 15;234:123642.
PMID: 36791941 DOI: 10.1016/j.ijbiomac.2023.123642

Although anionic polyelectrolyte hydrogel beads offer attractive adsorption of cationic dyes, phosphate adsorption is limited by electrostatic interactions. In this work, carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were modified with calcium carbonate (CaCO3) and/or bentonite (Be). The compatibility between CaCO3 and Be was proven by the homogeneous surface, as shown in the scanning electron microscopic images. Fourier-transform infrared and X-ray diffraction spectra further confirmed the existence of inorganic filler in the hydrogel beads. Although CMC/SA/Be/CaCO3 hydrogel beads attained the highest methylene blue and phosphate adsorption capacities (142.15 MB mg/g, 90.31 P mg/g), phosphate adsorption was significantly improved once CaCO3 nanoparticles were incorporated into CMC/SA/CaCO3 hydrogel beads. The kinetics of MB adsorption by CMC/SA hydrogel beads with or without inorganic fillers could be described by the pseudo-second-order model under chemical interactions. The phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads could be explained by the Elovich model due to heterogeneous properties. The incorporation of Be and CaCO3 also improved the phosphate adsorption through chemical interaction since Langmuir isotherm fitted the phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads. Unlike MB adsorption, the reusability of these hydrogel beads in phosphate adsorption reduced slightly after 5 cycles.

Matched MeSH terms: Alginates/chemistry; Bentonite/chemistry; Carboxymethylcellulose Sodium/chemistry; Hydrogels/chemistry
Crystallization and X-ray analysis of the T = 4 particle of hepatitis B capsid protein with an N-terminal extension

Tan WS, McNae IW, Ho KL, Walkinshaw MD

Acta Crystallogr Sect F Struct Biol Cryst Commun, 2007 Aug 01;63(Pt 8):642-7.
PMID: 17671358

Hepatitis B core (HBc) particles have been extensively exploited as carriers for foreign immunological epitopes in the development of multicomponent vaccines and diagnostic reagents. Crystals of the T = 4 HBc particle were grown in PEG 20,000, ammonium sulfate and various types of alcohols. A temperature jump from 277 or 283 to 290 K was found to enhance crystal growth. A crystal grown using MPD as a cryoprotectant diffracted X-rays to 7.7 A resolution and data were collected to 99.6% completeness at 8.9 A. The crystal belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 352.3, b = 465.5, c = 645.0 A. The electron-density map reveals a protrusion that is consistent with the N-terminus extending out from the surface of the capsid. The structure presented here supports the idea that N-terminal insertions can be exploited in the development of diagnostic reagents, multicomponent vaccines and delivery vehicles into mammalian cells.

Matched MeSH terms: Hepatitis B virus/chemistry*; Peptide Fragments/chemistry*; Virion/chemistry*; Nucleocapsid Proteins/chemistry*
Fulltext Characterization of electrosynthesized conjugated polymer-carbon nanotube composite: optical nonlinearity and electrical property

Bahrami A, Talib ZA, Shahriari E, Yunus WMM, Kasim A, Behzad K

Int J Mol Sci, 2012;13(1):918-928.
PMID: 22312294 DOI: 10.3390/ijms13010918

The effects of multi-walled carbon nanotube (MWNT) concentration on the structural, optical and electrical properties of conjugated polymer-carbon nanotube composite are discussed. Multi-walled carbon nanotube-polypyrrole nanocomposites were synthesized by electrochemical polymerization of monomers in the presence of different amounts of MWNTs using sodium dodecylbenzensulfonate (SDBS) as surfactant at room temperature and normal pressure. Field emission scanning electron microscopy (FESEM) indicates that the polymer is wrapped around the nanotubes. Measurement of the nonlinear refractive indices (n(2)) and the nonlinear absorption (β) of the samples with different MWNT concentrations measurements were performed by a single Z-scan method using continuous wave (CW) laser beam excitation wavelength of λ = 532 nm. The results show that both nonlinear optical parameters increased with increasing the concentration of MWNTs. The third order nonlinear susceptibilities were also calculated and found to follow the same trend as n(2) and β. In addition, the conductivity of the composite film was found to increase rapidly with the increase in the MWNT concentration.

Matched MeSH terms: Benzenesulfonates/chemistry; Polymers/chemistry*; Pyrroles/chemistry; Nanotubes, Carbon/chemistry*
Fulltext Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

Razak RA, Abdullah MM, Hussin K, Ismail KN, Hardjito D, Yahya Z

Int J Mol Sci, 2015 May 21;16(5):11629-47.
PMID: 26006238 DOI: 10.3390/ijms160511629

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

Matched MeSH terms: Polymers/chemistry*; Sodium Hydroxide/chemistry*; Water/chemistry; Silicates/chemistry*
Fulltext Acute oral toxicity and brine shrimp lethality of Elaeis guineensis Jacq., (oil palm leaf) methanol extract

Syahmi AR, Vijayarathna S, Sasidharan S, Latha LY, Kwan YP, Lau YL, et al.

Molecules, 2010 Nov 10;15(11):8111-21.
PMID: 21072022 DOI: 10.3390/molecules15118111

Elaeis guineensis (Arecaceae) is widely used in West African traditional medicine for treating various ailments. An evaluation on the toxicity of extracts of this plant is crucial to support the therapeutic claims. The acute oral toxicity and brine shrimp lethality of a methanolic extract of this plant was tested. Oral administration of crude extract at the highest dose of 5,000 mg/kg resulted in no mortalities or evidence of adverse effects, implying that E. guineensis is nontoxic. Normal behavioral pattern, clinical signs and histology of vital organs confirm this evidence. The E. guineensis extracts screened for toxicity against brine shrimp had 50% lethal concentration (LC₅₀) values of more than 1.0 mg/mL (9.00 and 3.87 mg/mL, at 6 and 24 h, respectively), confirming that the extract was not toxic. Maximum mortalities occurred at 100 mg/mL concentration while the least mortalities happened to be at 0.195 mg/mL concentration. The results of both tests confirm that E. guineensis is nontoxic and hence safe for commercial utilization.

Matched MeSH terms: Methanol/chemistry*; Plant Extracts/chemistry*; Plant Leaves/chemistry*; Arecaceae/chemistry*
Fulltext Study the effect of various wash-coated metal oxides over synthesized carbon nanofibers coated monolith substrates

Malekbala MR, Soltani S, Abdul Rashid S, Abdullah LC, Choong TSY

PLoS One, 2019;14(7):e0219936.
PMID: 31365558 DOI: 10.1371/journal.pone.0219936

In this research work, carbon nanofibers (CNFs) were synthesized on honeycomb monolith substrates using injection chemical vapor deposition (ICVD) technique. The effect of various wash-coated materials and catalyst promoter on the growth rate of CNFs on monolith substrates were examined. The characteristics of the synthesized CNFs-coated monolith composites were examined using Raman spectroscopy, Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), and Transmission electron microscopy (TEM) techniques. According to the textural characterization study, the specific surface area and pore volume of CNFs-coated monolith composites were significantly improved as compared to bare monolith which might be attributed to the growth of highly pure and aligned CNFs over monolith substrate. Besides that, the synthesized CNFs-coated monolith possessed extremely well thermal stability up to the temperature of 550 °C which was corresponded to the strong attachment of highly graphitized CNFs over monolith substrates.

Matched MeSH terms: Carbon/chemistry*; Metals/chemistry*; Oxides/chemistry; Nanofibers/chemistry*

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