SUMMARY:The aim of this study was to characterize the chemical composition and radical scavenging activity of Canterbury bells (Campanula medium) seed oil. C. medium seeds contained 9.2% extractable oil. The lipid classes, fatty acids, phytosterol and tocopherol composition of C. medium seed oil were determined. The amount of neutral lipids in the oil was the highest, followed by glycolipids and phospholipids. Linoleic and oleic were the main fatty acids. C. medium oil is characterized by high levels of phytosterols and β-sitosterol was the main compound. β-Tocopherol constituted 42.5% of the total tocopherol content followed by γ-tocopherol. The radical scavenging activity (RSA) toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and galvinoxyl radicals of C. medium oil were higher than those of extra virgin olive oil. The diverse potential uses of C. medium oil may make this plant industrially important.

Retroviral envelope (env)-like sequences in 2 cultivated allotetraploid cottons and their diploid progenitors have been identified and characterized in this study. DNA sequence analysis reveals that these sequences are heterogeneous. The observed sequence diversity, however, seems to preserve coding information. This is evidenced by the detection of the transmembrane domain (TM), which is the most conserved feature of the divergent retroviral env genes. The high ratio of synonymous to nonsynonymous changes suggests that these sequences are evolving under purifying selection. Phylogenetic analysis shows that Gossypium sequences closely cluster with a lineage of plant endogenous retroviruses that have an env-like gene. These results provide evidence for the antiquity and the wide diversity of env-like sequences in the Gossypium genome.

A two disk machine with a spherical disk mating a plain cylindrical one has been constructed to operate at different elliptical contact situations under various loads and rolling to sliding speeds. The disks axes can skew relative to each other so that various elliptical contacts could be tested. By the aid of specially modified evaporated transducers (Manganin band for pressure measurements and platinum band for temperature measurements), the elastohydrodynamic (EHD) pressure and temperature distributions could be accurately traced. Results, herein presented, confirmed that within the contact zone, the pressure distribution exhibits an almost Hertzian shape but with a second pressure peak (spike) near the trailing (exit) end of the oil film. The temperature has proven to display a distribution analogous to that described by the generated EHD pressure.

This part is a complimentary work to a previously published work on EHD lubrication behavior under pure sliding and combined rolling and sliding situations. In order to cover all aspects of EHD lubrication, the experimental work has been herein extended to present the results attained when two disks describe a pure rolling motion. A wide range of loads and speeds has been applied to the contacting disks under EHD regimes. The recorded pressure values and distribution confirm the existence of a second peak (spike) near the exit of the contact zone also under pure rolling situation. The spike has a value higher than maximum Hertzian pressure. A local constriction of oil film profile to identify the minimum EHD film thickness at trailing (exit) end of the film is observed to be nearby the location of the pressure spike. The results, compared to theoretical predictions, concluded that under pure rolling conditions, any increase in the applied load results in a corresponding increase in the developed pressure while a noticeable reduction in the minimum film thickness is recorded with decreasing rolling speeds.

We have used the polymerase chain reaction to analyze copia-like retrotransposons in the Egyptian cotton and its progenitors. All three cotton species studied contain reverse transcriptase fragments from copia-like retrotransposons. Sequence analysis of these reverse transcriptase fragments reveals that each is different from the others, with predicted amino acid diversities between 9 and 94%. The detection of stop codons and insertions/deletions in the derived amino acid sequences of the Gossypium RT clones, suggests that these clones represent defective retrotransposons. The presence of these sequences in G. barbadense progenitors, however, suggests the presence of active retrotransposons capable of producing new functional copies at an appropriate rate to compensate for the mutational loss of old ones. Phylogenetic analysis provided strong bootstrap support for a monophyletic origin of plant copia-like retrotransposons, yet showed high diversity within all species. Our results suggest that both vertical transmission of copia-like retrotransposons within G. barbadense lineages, and horizontal transmission between G. barbadense and its progenitors have played major roles in the evolution of copia-like retrotransposons in Gossypium.