The essential oil extracted from palmarosa (
Cymbopogon martinii) has proven anti-microbial properties against cells of
Saccharomyces cerevisiae. Low concentrations of the oil (0.1%) inhibited the ...growth of
S. cerevisiae cells completely. The composition of the sample of palmarosa oil was determined as 65% geraniol and 20% geranyl acetate as confirmed by GC–FTIR. The effect of palmarosa oil in causing K
+ leakage from yeast cells was attributed mainly to geraniol. Some leakage of magnesium ions was also observed. Blocking potassium membrane channels with caesium ions before addition of palmarosa oil did not change the extent of K
+ ion leakage, which was equal to the total sequestered K
+ in the cells. Palmarosa oil led to changes in the composition of the yeast cell membrane, with more saturated and less unsaturated fatty acids in the membrane after exposure of
S. cerevisiae cells to the oil. Some of the palmarosa oil was lost by volatilization during incubation of the oil with the yeast cells. The actual concentration of the oil components affecting the yeast cells could not therefore be accurately determined.
Geraniol in palmarosa oil led to changes in composition of the yeast cell membrane, with leakage of K
+ and Mg
2+ ions from cells.
Fifty‐one essential oils extracted from plants of known origin were tested for their antimicrobial activity against three bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and ...four yeasts, Torulopsis utilis, Schizosaccharomyces pombe, Candida albicans and Saccharomyces cerevisiae using the drop diffusion method. All showed antimicrobial activity against at least one of the micro‐organisms. Following this preliminary screening, 13 essential oils showing antimicrobial activity against at least five of the micro‐organisms were tested in the range 50 μg ml−1 to 500 μg ml−1 using broth micro dilution techniques with dimethylsulphoxide (DMSO) as a dispersing solvent. The concentration of most of the oils required for total inhibition of growth was >500 μg ml−1. Further studies on the antimicrobial action of cinnamon oil in the range 10–150 μg ml−1 showed that 50‐fold higher activity was found when no dispersing solvent was used.
Electron microscopic and biochemical studies of lignocellulose degradation by wood-rotting fungi have shown that enzymes such as lignin peroxidases, manganese dependent peroxidases, laccases and ...cellulases are too large to penetrate undegraded secondary wood cell walls. Degradation occurs by surface interaction between cell wall and enzymes, but initiation of decay at a distance from the fungal hyphae must involve diffusible low-molecular mass agents. The roles of hydrogen peroxide, veratryl alcohol, oxalate, Fe2(+)-Fe3(+) and Mn2(+)-Mn3(+), as such agents in lignocellulose degradation are discussed.
The tolerance of Paecilomyces variotii
to borate used as a wood preservative was investigated. P. variotii
was able to grow in the presence of up to 8 g l
−1 borax in liquid malt extract cultures and ...on solid substrates such as malt–agar and borax-treated Scots pine, larch, and spruce sawdusts. The fungus excreted increased amounts of β-
d-1,4-glucosidase when grown on borax-treated sawdust, a mechanism whereby increased amounts of glucose could be obtained for growth. Boron and glucose in the medium form a complex between the hydroxyl groups of glucose and boron, and supplying increased amounts of glucose in liquid culture enabled the fungus to grow in increasing concentrations of borax. A stable white mutant was selected from growth in high borate concentrations with similar characteristics to the parent with respect to β-
d-1,4-glucosidase secretion, but with a changed morphology in that it did not release aerial spores. The mutant has potential uses in integrated-control treatments as wood protectants.
The LHC Injectors Upgrade (LIU) program included new fast beam wire scanners (BWS) to meet the requirements of the higher brightness and intensity High Luminosity LHC (HL-LHC) beams. Seventeen LIU ...BWS have been installed during the LHC second long shutdown (LS2) and they are currently used in the daily operations of the LHC injectors. After giving an overview of the LIU project and the general beam instrumentation upgrades associated with it, this paper presents a short review of the mechanical design and layout of the LIU BWS, the electronics involved, and then focuses on the first results obtained during their commissioning.
The use of GC-Fourier transform (FT) IR of methylsilyl ethers of disaccharides to positively identify disaccharides is reported for the first time. The conditions required to separate these ...high-molecular-mass compounds by GC, in the quantities required for FT-IR detection are reported. Trimethylsilyl ethers can be used successfully. The use of dimethylsilyl ethers is not recommended as their instability, under the required operating conditions, resulted in fragmentation and rearrangements.
Despite the association with more advanced nodal stage, patients with human papillomavirus (HPV) positive oropharyngeal cancers have better outcomes. We examined whether the HPV can modify the effect ...of known prognostic factors in tonsillar cancer.
A total of 489 patients from 10 centres were followed up for recurrence or death for a median of 3.2 years. Determinants of the rate of locoregional recurrence, death from tonsillar cancer and overall survival were modelled using Cox regression.
The prognostic value of T and N stages were modified by HPV as indicated by statistically significant interaction terms. After adjusting for age, gender and treatment, T stage appeared relevant only for HPV-positive cancers (where a higher T stage was associated with worse outcomes). There was some evidence that N stage was a more relevant prognostic factor for HPV-negative than -positive cancers. There was no evidence that the HPV modifies the effect of age, gender or grade on outcomes.
This study suggests that the prognostic significance of the conventional staging system in tonsillar cancer is modified by HPV.
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