Isoaccepting Lysine Transfer Ribonucleic Acid Species of Pseudomonas Aeruginosa

Pseudomonas aeruginosa tRNA was treated with iodine, CNBr and N-ethylmaleimide,three thionucleotide-specific reagents. Reaction with iodine resulted in extensive loss of acceptor activity by lysine tRNA, glutamic acid tRNA, glutamine tRNA, serine tRNA and tyrosine tRNA. CNBr treatment resulted in high loss of acceptor ability by lysine tRNA, glutamic acid tRNA and glutamine tRNA. Only the acceptor ability of tyrosine tRNA was inhibited up to 66% by N-ethylmaleimide treatment, a reagent specific for 4-thiouridine. By the combined use of benzoylated DEAE-cellulose and DEAESephadex columns, lysine tRNA of Ps. aeruginosa was resolved into two isoaccepting species, a major, tRNAL'y and a minor, tRNA'Ys. Co-chromatography of 14C-labelled tRNALYS and 3H-labelled tRNALy, on benzoylated DEAE-cellulose at pH4.5 gave two distinct, non-superimposable profiles for the two activity peaks, suggesting that they were separate species. The acceptor activity of these two species was inhibited by about 95% by iodine and CNBr. Both the species showed equal response to codons AAA and AAG and also for poly(A) and poly(A1,Gl) suggesting that the anticodon of these species was UUU. Chemical modification of these two species by iodine did not inhibit the coding response. The two species of lysine of Ps. aeruginosa are truly redundant in that they are indistinguishable either by chemical modification or by their coding response.

Oxidase-peroxidase enzymes of Datura innoxia. Oxidation of formylphenylacetic acid ethyl ester

An enzyme system from Datura innoxia roots oxidizing formylphenylacetic acid ethyl ester was purified 38-fold by conventional methods such as (NH4)2SO4 fractionation, negative adsorption on alumina Cy gel and chromatography on DEAE-cellulose. The purified enzyme was shown to catalyse the stoicheiometric oxidation of formylphenylacetic acid ethyl ester to benzoylformic acid ethyl ester and formic acid, utilizing molecular O2. Substrate analogues such as phenylacetaldehyde and phenylpyruvate were oxidized at a very low rate, and formylphenylacetonitrile was an inhilating agents, cyanide, thiol compounds and ascorbic acid. This enzyme was identical with an oxidase-peroxidase isoenzyme. Another oxidase-peroxidase isoenzyme which separated on DEAE-chromatography also showed formylphenylacetic acid ethyl ester oxidase activity, albeit to a lesser extent. The properties of the two isoenzymes of the oxidase were compared and shown to differ in their oxidation and peroxidation properties. The oxidation of formylphenylacetic acid ethyl ester was also catalysed by horseradish peroxidase. The Datura isoenzymes exhibited typical haemoprotein spectra. The oxidation of formylphenylacetic acid ethyl ester was different from other peroxidase-catalysed reactions in not being activated by either Mn2+ or monophenols. The oxidation was inhibited by several mono- and poly-phenols and by catalase. A reaction mechanism for the oxidation is proposed.

Effect Of Human Chorionic Gonadotrophin And Ovine Luteinizing Hormone On Rat Ovarian Macromolecular Metabolism

Administration of human chorionic gonadotrophin (HCG) or ovine LH to immature rats primed with pregnant mare serum gonadotrophin (PMSG) stimulated the rate of synthesis of polyadenylic acid (poly A)-rich RNA in the ovaries. The rate of total RNA synthesis was not affected significantly by hormone treatment, whereas protein synthesis was enhanced. The increase in the rate of synthesis of poly(A)-rich RNA in the ovaries could be inferred as induction of messenger RNA synthesis after the hormone treatment. The poly(A)-rich nature of the isolated RNA was established by oligo(dT)–cellulose chromatography, binding to Millipore filter disks and hydridization with [3H]polyuridylic acid. The level of cyclic AMP in the ovaries of such rats was also raised after administration of LH, the increase coincided with the increase in the rate of synthesis of poly(A)-rich RNA. The implications of these results are discussed in the light of the biochemical basis of luteinization and the action of LH.

Harvest: A biotextile future

- Description of the work Harvest: A biotextile future consists of four bags constructed from kombucha, each utilizing a different approach to this material. The kombucha material is a byproduct of the fermented green tea, kombucha, and is comprised of a symbiotic culture of bacteria and yeast (SCOBY) that forms a fast growing curd or pellicle on the surface of the tea. This pellicle is harvested, washed, and dried to make a material with characteristics that can range between leather and paper in handle. The pellicle is one hundred per cent cellulose, with the individual fibres growing together to produce a durable and strong non-woven textile. Techniques explored with the dry kombucha material include folding, stitching, and laser etching. The final bags were designed with reference to classic tropes of fashion accessories: the briefcase, the clutch, the valise and the handbag. The valise included three jars in which the kombucha was displayed as ‘growing’ within the bag. - Research Background This work sits within an emerging field of practice in which fashion design intersects with biotechnology. Designers such as Suzanne Lee have explored constructing garments from bacteria byproducts, and bio-artists Oron Catts and Ionat Zurr have created ‘victimless leather’ grown from cultured cells. Although still speculative, these collaborations between science and design point to new material applications for fashion. Our work contributes to this area through testing both the growing of the textile and its application to construct durable fashion artefacts. - Research Contribution Harvest: A biotextile future makes two contributions to new knowledge in the area of design for sustainability within fashion. The first contribution lies in extending the technical experimentation required to grow and manipulate the textile. For the briefcase, the pattern shape was ‘grown’ into the required shape, using a shaped container. Other techniques used in the bags included weaving, folding and laser etching the material to extend its functional and decorative properties. Experimentation with the growing and drying of the material led to the production of a wide range of physical properties, in which the material was more brittle or flexible as required. The second research contribution lies in the proposal of this material for use in durable fashion accessories. The material is still speculative and small-scale in production, however the four bags illustrate the potential for kombucha as a biodegradable alternative to leather or synthetic materials. - Research Significance This interplay of science and design research opens up an exploration for a speculative future of sustainable, biodegradable textiles using live bacteria to enable ‘homegrown’ vegan apparel. The collaborators on this project include scientist Peter Musk and fashion designers Alice Payne and Dean Brough. Harvest: A biotextile future was exhibited at the State Library of Queensland’s Asia Pacific Design Library, 1-5 November 2015, as part of The International Association of Societies of Design Research’s (IASDR) biannual design conference. The work was chosen for display by a panel of experts, based on the criteria of design innovation and contribution to new knowledge in design.

A simple method for large-scale preparation of chick embryo tRNA

A simple method for preparing bulk quantities of tRNA from chick embryo has been developed. In this method chick embryos were homogenized in a buffer of pH 4.5, followed by deproteinization with phenol. The aqueous layer was allowed to separate under gravity. The resulting aqueous layer, after two more phenol treatments, was directly passed through a DEAE-cellulose column and the tRNA eluted therefrom with 1 Image NaCl. The tRNA prepared by this method was as active as the one prepared at neutral pH.

A new mixed-matrix membrane for DMFCs

A new mixed-matrix membrane based on stabilized phosphotungstic acid (PTA) incorporated to chitosan (CS)-hydroxy ethyl cellulose (HEC) for application in direct methanol fuel cells (DMFCs) is reported. Membranes are characterised using Fourier Transform Spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and their mechanical properties are evaluated. The PTA content in the CS-HEC blend and its influence on proton conductivity, water/methanol sorption, and methanol cross-over in the DMFC is studied. The DMFC with 3 wt. % stabilized PTA-CS-HEC mixed-matrix membrane delivers peak power-density of 58 mW/cm(2) at a load current-density of 210 mA/cm(2) with a lower methanol cross-over than that observed for a DMFC operating with a Nafion membrane electrolyte.

Effect of pretreatment on the formation of 5-chloromethyl furfural derived from sugarcane bagasse

Chloromethylfurfural (CMF), a valuable intermediate for the production of chemicals and fuel, can be derived in high yields from the cellulose component of biomass. This study examined the effect of sugar cane bagasse components and biomass architecture on CMF/bio-oil yield using a HCl/dichloroethane biphasic system. The type of pretreatment affected bio-oil yield, as the CMF yield increased with increasing glucan content. CMF yield reached 81.9% with bagasse pretreated by acidified aqueous ionic liquid, which had a glucan content of 81.6%. The lignin content of the biomass was found to significantly reduce CMF yield, which was only 62.3% with acid-catalysed steam exploded sample having a lignin content of 29.6%. The change of CMF yield may be associated with fibre surface changes as a result of pretreatment. The hemicellulose content also impacted negatively on CMF yield. Storage of the bio-oil in chlorinated solvents prevented CMF degradation.

Studies on the Cell Wall Structure and on the Mechanical Properties of Norway Spruce

The structure and the mechanical properties of wood of Norway spruce (Picea abies [L.] Karst.) were studied using small samples from Finland and Sweden. X-ray diffraction (XRD) was used to determine the orientation of cellulose microfibrils (microfibril angle, MFA), the dimensions of cellulose crystallites and the average shape of the cell cross-section. X-ray attenuation and x-ray fluorescence measurements were used to study the chemical composition and the trace element content. Tensile testing with in situ XRD was used to characterise the mechanical properties of wood and the deformation of crystalline cellulose within the wood cell walls. Cellulose crystallites were found to be 192 284 Å long and 28.9 33.4 Å wide in chemically untreated wood and they were longer and wider in mature wood than in juvenile wood. The MFA distribution of individual Norway spruce tracheids and larger samples was asymmetric. In individual cell walls, the mean MFA was 19 30 degrees, while the mode of the MFA distribution was 7 21 degrees. Both the mean MFA and the mode of the MFA distribution decreased as a function of the annual ring. Tangential cell walls exhibited smaller mean MFA and mode of the MFA distribution than radial cell walls. Maceration of wood material caused narrowing of the MFA distribution and removed contributions observed at around 90 degrees. In wood of both untreated and fertilised trees, the average shape of the cell cross-section changed from circular via ambiguous to rectangular as the cambial age increased. The average shape of the cell cross-section and the MFA distribution did not change as a result of fertilisation. The mass absorption coefficient for x-rays was higher in wood of fertilised trees than in that of untreated trees and wood of fertilised trees contained more of the elements S, Cl, and K, but a smaller amount of Mn. Cellulose crystallites were longer in wood of fertilised trees than in that of untreated trees. Kraft cooking caused widening and shortening of the cellulose crystallites. Tensile tests parallel to the cells showed that if the mean MFA is initially around 10 degrees or smaller, no systematic changes occur in the MFA distribution due to strain. The role of mean MFA in defining the tensile strength or the modulus of elasticity of wood was not as dominant as that reported earlier. Crystalline cellulose elongated much less than the entire samples. The Poisson ratio νca of crystalline cellulose in Norway spruce wood was shown to be largely dependent on the surroundings of crystalline cellulose in the cell wall, varying between -1.2 and 0.8. The Poisson ratio was negative in kraft cooked wood and positive in chemically untreated wood. In chemically untreated wood, νca was larger in mature wood and in latewood compared to juvenile wood and earlywood.

A study of the nanostructure of the cell wall of the tracheids of conifer xylem by x-ray scattering

The purpose of this study was to develop practical and reliable x-ray scattering methods to study the nanostructure of the wood cell wall and to use these methods to systematically study the nanostructure of Norway spruce and Scots pine grown in Finland and Sweden. Methods to determine the microfibril angle (MFA) distribution, the crystallinity of wood, and the average size of cellulose crystallites using wide-angle x-ray scattering were developed and these parameters were determined as a function of the number of the year ring. The mean MFA in Norway spruce decreases rapidly as a function of the number of the year ring and after the 7th year ring it varies between 6° and 10°. The mean MFA of Scots pine behaves the same way as the mean MFA of Norway spruce. The thickness of cellulose crystallites for Norway spruce and Scots pine appears to be constant as a function of the number of the year ring. The obtained mean values are 32 Å for Norway spruce and 31 Å for Scots pine. The length of the cellulose crystallites was also quite constant as a function of the year ring. The mean length of the crystallites for Norway spruce was 364 Å, while the standard deviation was 27 Å. The mass fraction of crystalline cellulose in wood is the crystallinity of wood and the intrinsic crystallinity of cellulose is the crystallinity of cellulose. The crystallinity of wood increases from the 2nd year ring to the 10th year ring from the pith and is constant after the 10th year ring. The crystallinity of cellulose obtained using nuclear magnetic resonance spectroscopy was 52% for both species. The crystallinity of wood and the crystallinity of cellulose behave the same way in Norway spruce and Scots pine. The methods were also applied to studies on thermally modified Scots pine wood grown in Finland. Wood is modified thermally by heating and steaming in order to improve its properties such as biological resistance and dimensional stability. Modification temperatures varied from 100 °C to 240 °C. The thermal modification increases the crystallinity of wood and the thickness of cellulose crystallites but does not influence the MFA distribution. When the modification temperature was 230 °C and time 4 h, the thickness of the cellulose crystallites increased from 31 Å to 34 Å.

Theoretical and computational approaches on heterogeneous nucleation

Nucleation is the first step of a first order phase transition. A new phase is always sprung up in nucleation phenomena. The two main categories of nucleation are homogeneous nucleation, where the new phase is formed in a uniform substance, and heterogeneous nucleation, when nucleation occurs on a pre-existing surface. In this thesis the main attention is paid on heterogeneous nucleation. This thesis wields the nucleation phenomena from two theoretical perspectives: the classical nucleation theory and the statistical mechanical approach. The formulation of the classical nucleation theory relies on equilibrium thermodynamics and use of macroscopically determined quantities to describe the properties of small nuclei, sometimes consisting of just a few molecules. The statistical mechanical approach is based on interactions between single molecules, and does not bear the same assumptions as the classical theory. This work gathers up the present theoretical knowledge of heterogeneous nucleation and utilizes it in computational model studies. A new exact molecular approach on heterogeneous nucleation was introduced and tested by Monte Carlo simulations. The results obtained from the molecular simulations were interpreted by means of the concepts of the classical nucleation theory. Numerical calculations were carried out for a variety of substances nucleating on different substances. The classical theory of heterogeneous nucleation was employed in calculations of one-component nucleation of water on newsprint paper, Teflon and cellulose film, and binary nucleation of water-n-propanol and water-sulphuric acid mixtures on silver nanoparticles. The results were compared with experimental results. The molecular simulation studies involved homogeneous nucleation of argon and heterogeneous nucleation of argon on a planar platinum surface. It was found out that the use of a microscopical contact angle as a fitting parameter in calculations based on the classical theory of heterogeneous nucleation leads to a fair agreement between the theoretical predictions and experimental results. In the presented cases the microscopical angle was found to be always smaller than the contact angle obtained from macroscopical measurements. Furthermore, molecular Monte Carlo simulations revealed that the concept of the geometrical contact parameter in heterogeneous nucleation calculations can work surprisingly well even for very small clusters.

Purification and properties of uridine hydrolase from mung-bean (Phaseolus radiatus) seedlings

The occurrence in plants of an enzyme system catalyzing the cleavage of uridine has been demonstrated. The enzyme from Phaseolus radiatus was purified about 132-fold with 24% recovery by a combination of procedures involving mild acid treatment, ammonium sulphate fractionation, negative adsorption on calcium phosphate gel and DEAE-cellulose chromatography. The enzyme cleaves uridine to uracil and ribose in the absence of phosphate indicating that the mechanism of cleavage was hydrolytic rather than phosphorolytic. The enzyme is specific to uridine and does not act on other purine and pyrimidine compounds. The enzyme shows maximum activity at pH 7.4 and has a temperature optimum of 45 °. It does not require metal ions for activity. Inhibition of the enzyme by p-chloromercuribenzoate as well as N-ethylmaleimide and the reversal of p-chloromercuribenzoate inhibition by sulfhydryl agents indicate the probable involvement of readily oxidizable sulfhydryl groups in enzyme activity.

Purification and properties of an inhibitor for nicotinamide-adenine dinucleotidase from Mycobacterium tuberculosis H37Rv

The excess of free inhibitor for the enzyme NADase present in the crude cell-free extracts of Mycobacterium tuberculosis H37Rv has been purified by chromatography on a DEAE-cellulose column and adsorption and elution from alumina Cγ-gel. Some of the properties of the purified inhibitor have been studied and attempts have been made to elucidate the nature of combination between the enzyme and the inhibitor. The purified inhibitor may be glycoprotein in nature, and considerable loss in the activity of the inhibitor preparations could be brought about by trypsin digestion. The inhibitor was specific for the enzymes from M. tuberculosis H37Rv or H37Ra and could be stored for at least 6 months in the frozen state below 0 ° without any significant loss in activity. The inhibition was noncompetitive with respect to the substrates, and the enzyme-inhibitor complex formed was undissociable.

Purification and properties of an inhibitor for nicotinamide-adenine dinucleotidase from Mycobacterium tuberculosis H37Rv

The excess of free inhibitor for the enzyme NADase present in the crude cell-free extracts of Mycobacterium tuberculosis H37Rv has been purified by chromatography on a DEAE-cellulose column and adsorption and elution from alumina Cγ-gel. Some of the properties of the purified inhibitor have been studied and attempts have been made to elucidate the nature of combination between the enzyme and the inhibitor. The purified inhibitor may be glycoprotein in nature, and considerable loss in the activity of the inhibitor preparations could be brought about by trypsin digestion. The inhibitor was specific for the enzymes from M. tuberculosis H37Rv or H37Ra and could be stored for at least 6 months in the frozen state below 0 ° without any significant loss in activity. The inhibition was noncompetitive with respect to the substrates, and the enzyme-inhibitor complex formed was undissociable.

Cloning,overexpression and purification of functionally active Saccharomyces cerevisiae Hop1 protein from scherichia coli

One of the major limitations to the application of high-resolution biophysical techniques such as X-crystallography and spectroscopic analyses to structure-function studies of Saccharomyces cerevisiae Hop1 protein has been the non-availability of sufficient quantities of functionally active pure protein. This has, indeed, been the case of many proteins, including yeast synaptonemal complex proteins. In this study, we have performed expression screening in Escherichia coli host strains, capable of high-level expression of soluble S. cerevisiae Hop1 protein. A new protocol has been developed for expression and purification of S. cerevisiae Hop1 protein, based on the presence of hexa-histidine tag and double-stranded DNA-Cellulose chromatography. Recombinant S. cerevisiae Hop1 protein was >98% pure and exhibited DNA-binding activity with high-affinity to the Holliday junction. The availability of the recombinant HOP1 expression vector and active Hop1 protein would facilitate structure-function investigations as well as the generation of appropriate truncated and site-directed mutant proteins, respectively. (C) 2010 Elsevier Inc. All rights reserved.

Studies on the enzyme hydrolysing flavin mononucleotide in plants: I. Partial purification and properties of the enzyme from Phaseolus radiatus

The partial purification of the enzyme hydrolysing FMN from extracts of greengram seeds (Phaseolus radiatus) is described. The procedures, which entailed precipitation of inert material by manganous sulfate and protamine sulfate treatment, fractional precipitation with alcohol and chromatography on CM-cellulose, afforded preparations whose specific activity was 200 times that of the initial crude extract. The preparation was comparatively specific for FMN. It also hydrolysed, to a much smaller extent, β-glycerophosphate, p-nitrophenyl phosphate and 5′-nucleotides. The differential effects of ions on the FMN and β-glycerophosphate hydrolysing activities are discussed.