Formation of 3-hexaprenyl-4-hydroxybenzoate by matrix-free mitochondrial membrane-rich preparations of yeast.

It has been shown that a 10 000 x g matrix-free mitochondrial membrane-rich preparation from commercial bakers' yeast is able to synthesize 3-all-transhexaprenyl-4-hydroxybenzoate from 4-hydroxybenzoate and isopentenyl pyrophosphate. The synthesis is Mg2+ dependent and is stimulated markedly by the primer for polyprenylpyrophosphate synthesis of 3-hexaprenyl-4-hydroxybenzoate from 4-hydroxybenzoate, isopentenyl pyrophosphate and 3,3-dimethylallyl pyrophosphate the priming function of 3,3-dimethylallyl pyrophosphate can be performed by either geranyl pyrophosphate (most efficient) or farnesyl pyrophosphate. At high Mg2+ concentrations, however, geranyl pyrophosphate and farnesyl pyrophosphate act mainly as sources of preformed side chains and 3-diprenyl- and 3-tripenyl-4-hydroxybenzoate, respectively, are produced. In the presence of a source of preformed polyprenyl pyrophosphates the membrane preparations catalysed the polyprenylation of methyl-4-hydroxybenzoate, 4-hydroxybenzaldehyde, 4-hydroxybenzylalcohol and 4-hydroxycinnamate. No evidence was obtained for the involvement of either 4-hydroxybenzoyl CoA or 4-hydroxybenzoyl-S-protein in the formation of 3-polyprenyl-4-hydroxybenzoates.     

Fluctuations in proline and other free amino acids during the mitotic cycle of the myxomycete Physarum polycephalum.

1. During synchronous growth of the acellular slime mould Physarum polycephalum the free amino pool had two maxima, one of 650 units [nmol/plasmodium dry weight (mg)] at metaphase and the other of 780 units in mid G2 with minima of 550 units before and after mitosis. 2. Proline formed 20--25% of the total pool with aspartic acid, glutamic acid, threonine, valine, leucine, lysine and arginine making up 55% of the pool. 3. The fluctuation of proline during the mitotic cycle was quite different from that of the other amino acids and was transiently very low during telophase.     

An 18O2 study of the biosynthesis and metabolism of rishitin

An ¹⁸O₂ study has shown that the hydroxyl oxygen atoms of lubimin, rishitin and two metabolites of rishitin, 13-hydroxyrishitin and 11,12-dihydro-13 (or 12)-hydroxyrishitin, are derived from molecular oxygen. It could not be shown that the aldehyde oxygen of lubimin was derived from molecular oxygen, probably due to its exchange with the oxygen atom of water. These findings have established that mono-oxygenases are involved in all of the hydroxylation reactions and that, contrary to a previous proposal, 11,12-dihydro-13 (or 12)-hydroxyrishitin is not formed from rishitin by hydration.     

Investigation of avenacin-deficient mutants of Avena strigosa

The biosynthesis of cyclic triterpenoids in ten saponin-deficient (sad) mutant varieties of the diploid oat Avena strigosa is reported. Two mutants were found to be deficient in 2,3-oxidosqualene:beta-amyrin cyclase (OSbetaAC) (EC 5.4.99) and thus unable to produce the beta-amyrin necessary for the production of avenacins. The other mutants studied had post beta-amyrin lesions. 2,3-Oxidosqualene:cycloartenol cyclase (OSCC) (EC 5.4.99.8) needed for sterol formation was present in all ten mutants.     

Epidemiological typing of Bacillus cereus by amplified fragment length polymorphism

A simple amplified fragment length polymorphism method was developed for the epidemiological typing of Bacillus cereus. The method was applied to 21 cultures from seven food poisoning and eight non-food poisoning incidents. Results were compared with those obtained by conventional serotyping using flagellar antigens and assessed in relation to epidemiological data. Amplified fragment length polymorphism was found to be highly reproducible and 16 different profiles (each unique to the 15 incidents) were recognized. The method was also able to discriminate three subtypes within serotype H1, which is responsible for the majority of the emetic type of B. cereus food poisoning in England and Wales.     

Public health investigations of Salmonella Enteritidis in catering raw shell eggs, 2002-2004

AIMS: In response to a dramatic change in the epidemiology of Salmonella Enteritidis in England and Wales thought to be associated with raw shell eggs, the Health Protection Agency initiated public health investigations to establish the incidence of Salmonella contamination and origin of eggs used by catering premises implicated in outbreaks of Salm. Enteritidis. METHODS AND RESULTS: Between October 2002 and November 2004, 16 971 eggs were sampled and Salmonella were recovered from 3.4%. Salmonella was isolated from 5.5% and 6.3% of Spanish and eggs of unknown origin, respectively, used in catering premises linked to outbreaks, a level significantly higher than that (1.1%) found in nonLion Quality UK eggs sampled. The small sample of UK Lion Quality eggs tested (reflecting their lack of use in premises visited) did not contain Salmonella. Several phage types of Salm. Enteritidis other than phage type 4 (PT 4) were identified with nonUK eggs. CONCLUSIONS: Eggs from Spain were implicated as a major source of infection. Eggs were contaminated more frequently with Salmonella when shells were dirty and/or cracked, and stored at above 8 degrees C. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of Spanish eggs by the catering sector has been identified as a consistent significant factor in many of the outbreaks caused by Salm. Enteritidis nonPT4 in England and Wales during 2002-2004. Advice to caterers and hospitals that raw shell eggs should not be used in food that will either not be cooked or only lightly cooked should be reinforced.     

Multiple-locus variable-number tandem repeat analysis of Salmonella enterica subsp. enterica serovar Typhimurium: comparison of isolates from pigs, poultry and cases of human gastroenteritis

AIMS: Pulsed-field gel electrophoresis (PFGE) and variable number tandem repeat (VNTR) profiles of 195 epidemiologically unrelated Salmonella Typhimurium strains isolated in 1997-2004 from pigs were analysed and the results compared to establish the discriminatory ability of each method. In order to investigate the epidemiology of S. Typhimurium from different populations, the VNTR profiles from pigs were compared with those obtained from 190 S. Typhimurium strains isolated from poultry and 186 strains isolated from human cases of gastroenteritis. METHODS AND RESULTS: A total of 195 strains of S. Typhimurium were tested by PFGE and VNTR. For PFGE, the restriction enzyme XbaI was used, and for VNTR, the number of repeats at five loci (STTR 9, 5, 6, 10pl and 3) were counted and assigned an allele number based on an established VNTR scheme. The results obtained showed improved discrimination of VNTR when compared with PFGE with 34 PFGE profiles identified compared with 96 different VNTR profiles for the pig isolates and 56 different VNTR types within the most common PFGE type. Within the three different populations, VNTR showed distinct subpopulations of VNTR type related not only to source, but also demonstrated common VNTR types within samples obtained from humans, poultry and pigs, especially in strains of phage type DT104. CONCLUSIONS: VNTR has taken the discrimination to a further level than that obtained through PFGE, and demonstrated an overlap in the genetic diversity of isolates tested across the three different populations, confirming previous suggestions that animals have an involvement in the dissemination of S. Typhimurium through the food chain. SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella Typhimurium remains an important concern as a food-borne zoonotic agent. The VNTR strategy described provides an accurate method of tracing strain dissemination, and adds a further level of discrimination to the PFGE type, providing potential benefits to epidemiological studies and the possibility of deciphering source attribution of cases.     

Phage type 193 of Salmonella typhimurium contains different chromosomal genotypes and multiple IS 200 profiles

Abstract The common phage type 193 of Salmonella typhimurium was analyzed with respect to molecular markers of chromosomal genotype. Three profiles of the 16S rRNA genes and seven profiles of the DNA insertion element of IS2 00 were found among tne representative strains of DT193. The IS 200 profiles found within this single phage type were highly diverse, confirming that DT193 is a composite phage type containing several distinct clones and hybrid lines. IS2 00 profiling is thus appropriate both for primary strain discrimination, and for subdivision within certain phage types of S. typhimurium , such as DT193. This rapid molecular definition of clonality will be useful for the epidemiological investigation of food poisoning outbreaks.     

Drug resistance in Shigella dysenteriae,S flexneri and S boydii in England and Wales: increasing incidence of resistance to trimethoprim.

A total of 2753 strains of shigella belonging to subgroups A, B, and C that were isolated from patients in England and Wales during the period from 1979 to mid-1983 were studied. Of these, 1690 (61%) were from patients recently returned from abroad or in contact with recent travellers, and 760 (45%) of these affected travellers from the Indian subcontinent. The number of strains resistant to sulphonamides and streptomycin remained at a high level throughout (average 76% and 72% respectively). Resistance to tetracyclines, ampicillin, and chloramphenicol rose, reaching 63%, 51%, and 48%, respectively, in 1982. Strains resistant to trimethoprim were seen in substantial numbers for the first time and increased from 1.3% of all strains in 1979 to 9.9% in 1982 and 16.8% in the first half of 1983. The proportion of patients with recent foreign contact was notably smaller among those with strains resistant to trimethoprim than among those with strains sensitive to trimethoprim. The increase in resistance to trimethoprim might partly result from the use in Britain of compounds containing trimethoprim for the treatment of shigellosis.