Prevalence of sensitization to 'improver' enzymes in UK supermarket bakers.

BACKGROUND: Supermarket bakers are exposed not only to flour and alpha-amylase but also to other 'improver' enzymes, the nature of which is usually shrouded by commercial sensitivity. We aimed to determine the prevalence of sensitization to 'improver' enzymes in UK supermarket bakers. METHODS: We examined the prevalence of sensitization to enzymes in 300 bakers, employed by one of two large supermarket bakeries, who had declared work-related respiratory symptoms during routine health surveillance. Sensitization was determined using radioallergosorbent assay to eight individual enzymes contained in the specific 'improver' mix used by each supermarket. RESULTS: The prevalence of sensitization to 'improver' enzymes ranged from 5% to 15%. Sensitization was far more likely if the baker was sensitized also to either flour or alpha-amylase. The prevalence of sensitization to an 'improver' enzyme did not appear to be related to the concentration of that enzyme in the mix. CONCLUSIONS: We report substantial rates of sensitization to enzymes other than alpha-amylase in UK supermarket bakers; in only a small proportion of bakers was there evidence of sensitization to 'improver mix' enzymes without sensitization to either alpha-amylase or flour. The clinical significance of these findings needs further investigation, but our findings indicate that specific sensitization in symptomatic bakers may not be identified without consideration of a wide range of workplace antigens.

Vancouver's needle exchange program.

To stem the spread of HIV among intravenous drug users, and between them and their sexual partners and offspring, Vancouver initiated a multifaceted "ways and means" needle exchange program in March of 1989. As of the end of October, over 2,600 users have registered. The needle exchange rate has increased steadily, reaching a peak of 98% in November. Increases have also been noted in the number of regular users, and requests for referral to addition, medical, social and HIV-related services. Outreach services, especially using a van, have expanded program availability. Success in terms of clientele response is accredited primarily to the nonjudgemental, nonintrusive approach. The main problems have been the lack of addiction treatment services, financial and personnel constraints created by the large enrollment, and difficulties with Federal/Provincial funding. Funding for evaluation has been requested.

Isolation of poly-alpha-L-guluronate lyase from Klebsiella aerogenes.

The bacterium Klebsiella aerogenes type 25 produces an extracellular alginolyase which has been partly purified. The enzyme is specific for the alpha-L-guluronosyl linkages in whole alginate and fractions therefrom. The end products of its action on polyguluronic acid blocks are mainly the unsaturated di- and tri-saccharides, with a smaller proportion of the homologous tetrasaccharide. Some general properties of the enzyme are reported.

The agar-type polysaccharide from the red alga Ceramium rubrum.

Aqueous extraction of the red alga C. rubrum gave a galactan sulphate and, possibly, a separate glucan and xylan. The galactan sulphate has an alternating structure of the agar-type with D-galactose or 6-O-methyl-D-galactose as one alternating unit, and L-galactose, 3,6-anhydro-L-galactose, and their respective 2-methyl ethers as the other unit. Sulphate hemi-ester groups are present on position 6 of both D- and L-galactose residues, with smaller amounts on positions 2 and 4 of, probably, D-galactose residues. The polysaccharide differs from others previously examined in that most of the L-galactose residues are non-sulphated.

The galactan sulphate of the red alga Polysiphonia lanosa.

The structure of the galactan sulphate of P. lanosa has been established by a combination of methylation, treatment with alkali, and partial methanolysis of the alkali-treated polysaccharide to give derivatives of agarobiose. The polysaccharide belongs to the agar class, in which 3-linked derivatives of beta-D-galactose alternate with 4-linked derivatives of alpha-L-galactose in a repeating sequence. In addition to D-galactose itself, the 3-linked units include 6-O-methyl-D-galactose, D-galactose 6-sulphate, and a hitherto unreported unit, 6-O-methyl-D-galactose 4-sulphate. The 4-linked units include L-galactose 6-sulphate, 2-O-methyl-L-galactose 6-sulphate, and 3,6-anhydro-L-galactose.

The action of a bacterial agarase on agarose, porphyran and alkali-treated porphyran.

1. A purified extracellular agarase from a Cytophaga species was used to hydrolyse agarose, porphyran and alkali-treated porphyran. 2. The hydrolysate from agarose was separated by gel filtration into the series of neoagarosaccharides, the predominant member of which was the tetrasaccharide. 3. Enzyme action on alkali-treated porphyran gave neoagarosaccharides and other oligosaccharides containing 6-O-methyl-d-galactose units. From the composition of these oligosaccharides it is deduced that action of the enzyme on a d-galactosidic linkage is four to five times faster than on the 6-O-methyl-d-galactosidic linkage. 4. Enzyme action on native porphyran gives a similar series of oligosaccharides but in smaller yield, much of the polysaccharide being either not degraded or only degraded to a series of large, highly sulphated oligosaccharides. 5. For porphyran, it is concluded that 6-O-methyl ether groups are distributed randomly on half the d-galactose units, but that the 6-sulphate groups on l-galactose units tend to occur in blocks.

The specificity of an agarase from a Cytophaga species.

1. The extracellular agarase from a Cytophaga species was shown to have no action on neoagarobiose, neoagarotetraose or their analogues containing 6-O-methyl-d-galactose residues. 2. The action of the enzyme on neoagaro-octaose suggests that scission of the central beta-d-galactosidic linkage, to form two molecules of tetrasaccharide, is the preferred mode of action; however, both exterior d-galactosidic linkages in the octasaccharide and both in neoagarohexaose are hydrolysed at a somewhat lower rate. 3. Sulphated oligosaccharides produced by prolonged enzyme action on porphyran have a minimum degree of polymerization of about 8-10units. 4. For such sulphated oligosaccharides to be further hydrolysed by enzyme action, it is suggested that an unmodified neoagarotetraose residue must be present in the oligosaccharide. 6. A new method for determining the degree of polymerization of these large oligosaccharides is described.

An extracellular agarase from a Cytophaga species.

1. An extracellular enzyme has been isolated from cultures of the bacterium growing on agar or porphyran. 2. Partial purification of the enzyme has been achieved by precipitation with ammonium sulphate followed by gel filtration on DEAE-Sephadex A-50. 3. The optimum conditions for the enzyme acting on porphyran are pH7.2 and a temperature of 40-41 degrees . 4. The enzyme has an endoaction, producing a rapid decrease in viscosity of agar or porphyran solutions with little development of reducing power. 5. From the action of the enzyme on various polysaccharides, it is concluded that the enzyme is specific for the agarose structure.

Studies in the epidemiology of tinea pedis. IX. Tinea pedis and erythrasma in new patients at a chiropody clinic.

The feet of 259 new patients at a chiropody clinic were examined for tinea pedis, onychomycosis, and erythrasma: 23% of men and 4% of women were infected by dermatophytes, and the nails of seven males were infected by non-dermatophytes. Of 200 patients examined under Wood's light 37% showed the coral-red fluorescence of erythrasma.Of the 259 patients, 9.7% were infected by Trichophyton interdigitale, 2.7% by T. rubrum, and 1.5% by Epidermophyton floccosum. Reasons are given, based on the method of selection of the patients, for supposing that T. interdigitale is still the dominant cause of tinea pedis in the population at large, despite figures from dermatological clinics suggesting the dominance of T. rubrum. The high incidence of infection in males compared with females corresponds with similar findings in school-children.

The enzymic degradation of porphyran.

1. The algal galactan, porphyran, was incubated with enzymes from a Cytophaga sp. and the products were examined. 2. Only about 30% of the porphyran was recovered in the form of oligosaccharides, the remainder being of high molecular weight. 3. Among the saccharides were d-galactose, 6-O-methyl-d-galactose, neoagarobiose, neoagarotetraose and oligosaccharides containing 6-O-methyl-d-galactose, the principal of which has been tentatively identified as 6(3)-O-methyl-neoagarotetraose. Fragments containing sulphate were also isolated but not identified. 4. Within the alternating sequence of the d- and l-forms of derivatives of galactose in porphyran, 6-O-methyl-d-galactose replaces d-galactose in a random manner.

The hydrolysis of algal galactans by enzymes from a Cytophaga species.

1. Two bacteria were isolated from sea water by the enrichment culture technique, both of which could utilize the galactan sulphate, porphyran, as sole source of carbon. 2. From the cells of one bacterium, classified as a Cytophaga sp., hydrolytic enzymes were isolated. 3. Partial purification of the enzymes is described and some of the properties of the principal enzymes have been studied. 4. The action of the enzymes on several galactan sulphates of red algae suggests that an agarase is present in the mixture.