Review: intellectual property aspects of plant transformation

One of the recurring themes of the debates concerning the application of genetic transformation technology has been the role of Intellectual Property Rights (IPR). This term covers both the content of patents and the confidential expertise usually related to methodology and referred to as 'Trade Secrets'. This review explains the concepts behind patent protection, and discusses the wide-ranging scope of existing patents that cover all aspects of transgenic technology, from selectable markers and novel promoters to methods of gene introduction. Although few of the patents in this area have any real commercial value, there are a small number of key patents that restrict the 'freedom to operate' of new companies seeking to exploit the methods. Over the last 20 years, these restrictions have forced extensive cross-licensing between ag-biotech companies and have been one of the driving forces behind the consolidation of these companies. Although such issues are often considered of little interest to the academic scientist working in the public sector, they are of great importance in any discussion of the role of 'public-good breeding' and of the relationship between the public and private sectors.

Aspects of isolation underpinning mitotic behaviour in lupin protoplasts

This study reports on the influence of critical isolation factors on the subsequent culture of protoplasts of Lupinus albus L. Protoplasts were isolated from in vitro seedling cotyledons of five early maturing accessions in which protoplast yields and division frequencies appeared to be correlated as a high protoplast yield corresponded with a high division frequency. The overall difference among the accessions for mitosis was non- significant, although the highest yield and division frequency were observed in accession LA132, with Alban giving a significantly lower level. Accession Lucrop produced the lowest number of protoplasts, all of which collapsed during culture. Of the enzyme types used for tissue maceration, Pectolyase Y23, was significantly inferior to Macerase in terms of giving way to mitosis. The extent of division in Macerase- isolated protoplast population was 266% higher than that in the Pectolyase Y23- isolated one. The physiological maturity level of the explant, expressed in terms of developmental age, was optimal when 14 - 18- day- old seedling cotyledons were used for protoplast production and culture, rather than more mature ones, despite higher protoplast yields in the latter. On K8p medium, the protoplast division frequency was 129% greater when 18- day- old seedling cotyledons were used, than that with any other treatment. This work on protoplast culture of the potentially important lupin species, which is a pulse rich in dietary protein, oil and fibre, allows a further understanding of the biology, with an aim to advance lupin biotechnology.

A mechanistic study of cyclic siloxane pyrolyses at low pressures

Matrix isolation IR spectroscopy has been used to study the vacuum pyrolysis of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4) and decamethyl cyclopentasiloxane (D5), and the results interpreted in the context of various kinetic models. In particular, it is shown that the significant pyrolysis products - which include CH3, CH4, C2H2, C2H4, C2H6 and SiO - may be satisfactorily accounted for by radical reactions involving dimethylsiloxane (D1), and estimates are made of the various chain lengths for the proposed reactions based on a range of ambient conditions.

A mechanistic study of the low pressure pyrolysis of linear siloxanes

Matrix isolation IR spectroscopy has been used to study the vacuum pyrolysis of 1,1,3,3-tetramethyldisiloxane (L1), 1,1,3,3,5,5-hexamethyltrisiloxane (L2) and 3H,5H-octamethyltetrasiloxane (L3) at ca. 1000 K in a flow reactor at low pressures. The hydrocarbons CH3, CH4, C2H2, C2H4, and C2H6 were observed as prominent pyrolysis products in all three systems, and amongst the weaker features are bands arising from the methylsilanes Me2SiH2 (for L1 and L2) and Me3SiH (for L3). The fundamental of SiO was also observed very weakly. By use of quantum chemical calculations combined with earlier kinetic models, mechanisms have been proposed involving the intermediacy of silanones Me2Si = O and MeSiH = O. Model calculations on the decomposition pathways of H3SiOSiH3 and H3SiOSiH2OSiH3 show that silanone elimination is favoured over silylene extrusion.

High-resolution crystal structure of the intramolecular d(TpA) thymine-adenine photoadduct and its mechanistic implications

A high-resolution crystal structure is reported for d(TpA)*, the intramolecular thymine-adenine photoadduct that is produced by direct ultraviolet excitation of the dinucleoside monophosphate d(TpA). It confirms the presence of a central 1,3-diazacyclooctatriene ring linking the remnants of the T and A bases, as previously deduced from heteronuclear NMR measurements by Zhao et al. (The structure of d(TpA)*, the major photoproduct of thymidylyl-(3'-5')-deoxyadenosine. Nucleic Acids Res., 1996, 24, 1554-1560). Within the crystal, the d(TpA)* molecules exist as zwitterions with a protonated amidine fragment of the eight-membered ring neutralizing the charge of the internucleotide phosphate monoanion. The absolute configuration at the original thymine C5 and C6 atoms is determined as 5S,6R. This is consistent with d(TpA)* arising by valence isomerization of a precursor cyclobutane photoproduct with cis-syn stereochemistry that is generated by [2 + 2] photoaddition of the thymine 5,6-double bond across the C6 and C5 positions of adenine. This mode of photoaddition should be favoured by the stacked conformation of adjacent T and A bases in B-form DNA. It is probable that the primary photoreaction is mechanistically analogous to pyrimidine dimerization despite having a much lower quantum yield.

Doped sodium aluminium hydrides as hydrogen storage materials: characterizations and mechanistic insights

The dehydriding and rehydriding of sodium aluminium hydride, NaAlR4, is kinetically enhanced and rendered reversible in the solid state upon doping with a small amount of catalyst species, such as titanium, zirconium or tin. The catalyst doped hydrides appear to be good candidates for development as hydrogen carriers for onboard proton exchange membrane (PEM) fuel cells because of their relatively low operation temperatures (120-150 degrees C) and high hydrogen carrying capacities (4-5 wt.%). However, the nature of the active catalyst species and the mechanism of catalytic action are not yet known. In particular, using combinations of Ti and Sri compounds as dopants, a cooperative catalyst effect of the metals Ti and Sn in enhancing the hydrogen uptake and release kinetics is hereby reported. In this paper, characterization techniques including XRD, XPS, TEM, EDS and SEM have been applied on this material. The results suggest that the solid state phase changes during the hydriding and dehydriding processes are assisted through the interaction of a surface catalyst. A mechanism is proposed to explain the catalytic effect of the Sn/Ti double dopants on this hydride.

Ultrasonic chemical oxidative degradations of 1,3-dialkylimidazolium ionic liquids and their mechanistic elucidations

A highly efficient process for oxidative degradation of 1,3-dialkylimidazolium ionic liquids in hydrogen peroxide/acetic acid aqueous medium assisted by ultrasonic chemical irradiation is, for the first time, described. It is shown that more than 93% of the 1,3-dialkylimidazolium cation with the corresponding Cl-, Br-, BF4- and PF6- counter-anions at a concentration of 2.5 mM can be degraded at 50 degrees C within 12 h while at 72 h the conversions approach 99%. A tentative mechanism for the degradation of these ILs is for the first time proposed through a detailed kinetic analysis of several characteristic transients and/or immediate products, which are identified during the ILs degradation using GC-MS. The results clearly indicate that three hydrogen atoms in the imidazolium ring are the first sites preferably oxidized, followed by cleavage of the alkyl groups attached to the N atoms from the ring. The nature of the alkyl chain length on the imidazolium ring and the type of counter anion do not seem to affect the degradation process. Further, selective fragmentations of C-N bonds of the imidazolium or derived ring lead to ring opening, forming degraded intermediates. It is also shown that acetoxyacetic acid and biurea are the final kinetically stable degraded products from the ILs under the degradation conditions.

Analytical and compositional aspects of isoflavones in food and their biological effects

This paper provides an overview of analytical techniques used to determine isoflavones (IFs) in foods and biological fluids with main emphasis on sample preparation methods. Factors influencing the content of IFs in food including processing and natural variability are summarized and an insight into IF databases is given. Comparisons of dietary intake of IFs in Asian and Western populations, in special subgroups like vegetarians, vegans, and infants are made and our knowledge on their absorption, distribution, metabolism, and excretion by the human body is presented. The influences of the gut microflora, age, gender, background diet, food matrix, and the chemical nature of the IFs on the metabolism of IFs are described. Potential mechanisms by which IFs may exert their actions are reviewed, and genetic polymorphism as determinants of biological response to soy IFs is discussed. The effects of IFs on a range of health outcomes including atherosclerosis, breast, intestinal, and prostate cancers, menopausal symptoms, bone health, and cognition are reviewed on the basis of the available in vitro, in vivo animal and human data.