A total of 89 strains designated Lactobtrcillus acidophilus were examined for physiological properties, type of lactic acid produced, cell wall sugar pattern, guanine plus cytosine content of deoxyribonucleic acid (DNA), and DNA homology values compared with selected reference strains. Immunological reactions among a group of the strains were determined by gel diffusion tests, using antiserum to purified lactic acid dehydrogenase (LDH) from a single strain (Sharpe strain AM). Antiserum to glyceraldehyde-3-phosphate dehydrogenase from strain ATCC 4356 was used in microcomplement fixation tests to determine relationships among some strains. DNA preparations from 78 of the 89 strains of L. acidophilus were distributed among six distinct homology groups, designated A l , A2, A3, A4, B1, and B2. The A group strains had 20 to 30% intergroup homology but very low homology to groups B1 and B2. Likewise, the strains in the two B groups had 20 to 30% intergroup homology but very low homology to the A group strains. Nine strains did not fall into any of the six homology groups.The guanine plus cytosine contents of the DNAs in strains comprising the six homology groups varied from 32 to 38 mol%. In the nine strains not falling into any of the homology groups, the guanine plus cytosine contents were 39 to 47 mol% Homology group Al, which includes the neotype strain of L. acidophilus (ATCC 4356), is very homogeneous, with most strains showing 95% or more homology to the reference strain. This group corresponds to LDH serogroup 111. Strains in the other homology groups showed 60 to 90% homology to their reference strains. Strains of LDH serogroup I1 were found in homology groups A2, A3, and A4, and those in LDH serogroup I were in homology groups B1 and B2. In general, the glyceraldehyde-3-phosphate dehydrogenase serology results correlated well with the LDH results. Other phenotypic test results were similar for all of the DNA homology groups. It is recommended that homology group A1 be designated L. acidophilus and that strain ATCC 4356 remain the neotype strain.In 1900, Moro isolated from infant feces grampositive, asporogenous rods, which he named Bacillus acidophilus (26). In 1929, this species was included by Holland in the genus Lactobacillus (16). The original strain of Moro was probably lost (13), and its description, according to present day standards, is very incomplete. Moreover, investigators tended to identify all new Lactobacillus isolates from mouths and from intestinal and vaginal floras as strains of Lactobacillus acidophilus. It was only in 1970 that Hansen and Mocquot adequately described this species and designated a neotype strain for it (ATCC 4356) according to the recommendations of the International Subcommittee on the Taxonomy of Lactobacilli and Closely Related Organisms (13, 14). The description of L. acidophilus by Hansen and Mocquot was derived from the important taxonomic work of Rogosa and Sharpe (29) The guanine plus cytosine (G+C) content of the deoxyribonucleic acid (DNA) of several strains ...

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1. The tissue contents of hexose monophosphate, N-acetylglucosamine 6-phosphate, UDP-glucose, UDP-galactose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine and UDP-glucuronic acid were determined in the skin of young rats less than 1 day post partum. Tissue-space determinations were used to calculate their average cellular concentrations. 2. The incorporation of [U-(14)C]-glucose into the intermediates was recorded with time and their rates of turnover were calculated. The results demonstrated product-precursor relationships along the pathway of hexosamine synthesis and that of hexuronic acid synthesis. The rates of synthesis of UDP-N-acetylhexosamine and UDP-glucuronic acid were 1.5+/-0.3 and 0.24+/-0.03mmumoles/min./g. of tissue respectively. These results indicated the average turnover time of the total tissue glycosaminoglycans to be about 5 days.

1. Carefully recrystallized samples of inulin have been analysed chromatographically for low-molecular-weight contaminants. The analysis of the samples revealed amounts of low-molecular-weight polyfructosans amounting to 5-10% of the inulin. 2. The possible polymorphism of inulin, its solubility behaviour and suggestions of association in solution are discussed. 3. Physical techniques suggest considerable polydispersity. Ultracentrifugation gives a weight-average molecular weight (M(w)) 7250, whereas osmotic-pressure measurements suggest a number-average molecular weight (M(n)) 5600. 4. A probable steric model is suggested of a helix repeating every four residues, of diameter 12A and axial ratio 7.5-10. 5. Fractionation of the inulin on columns of Sephadex G-25 show a pronounced polydispersity. 6. Some doubt is cast on the reliability of inulin as an indicator of physiological volumes of distribution in body fluids.

1. Glucosamine synthetase (l-glutamine-d-fructose 6-phosphate aminotransferase, EC 2.6.1.16) was purified about 300-fold from rat liver by two techniques. One procedure utilized the protective action of fructose 6-phosphate and gave a relatively stable preparation, the other yielded an unstable enzyme (half-life of about 20h), free of contaminant activities, on which kinetic experiments were performed. Although the properties of the two preparations showed slight differences, the unstabilized form could be converted into the stabilized form. 2. During preparation the enzyme retained its sensitivity to the feedback inhibitor, UDP-N-acetylglucosamine. 3. The reversibility of the enzyme-catalysed reaction could not be demonstrated. There was no apparent requirement for a cofactor. 4. The pH optimum was at 7.5, at which pH the reaction obeyed a Ping Pong Bi Bi rate equation. At pH values outside the range 6.9-7.6 and at temperatures below 29 degrees C the velocity was described by an ordered Bi Bi rate equation. 5. The molecular weight of the enzyme, determined by two procedures, was 360000-400000. 6. The aminotransferase was unable to utilize ammonia as a substrate.

X-ray-diffraction patterns of hyaluronate fibres from a variety of sources were obtained. Sodium hyaluronate gives well-defined patterns which index on a hexagonal unit cell with dimensions a 1.17±0.01nm and a fibre repeat-distance of 2.85 ±0.03nm. A further form of sodium hyaluronate is produced by annealing at 60°C in 75 % relative humidity. This stable state indexes on a hexagonal unit cell of unchanged fibre repeatdistance but with a = 1.87nm. The chain conformation is a threefold helix. Analysis of these diffraction patterns led to two tentative structures for sodium hyaluronate, involving different packing of the polysaccharide chains. The significance of side-chain interaction is discussed. Hyaluronic acid produces an X-ray pattern different from that obtained with the sodium salt. The fibre repeat-distance is 1.96±0.02nm and the unit cell appears to be monoclinic. The chain conformation is a twofold helix and conformational change between free acid and monovalent salt is discussed. These findings, together with model-building experiments, are interpreted as indicating a highly ordered structure, and the physical properties of hyaluronate solutions with regard to molecular shape and polyelectrolyte behaviour are rationalized.

1. The amino acid analysis of UDP-glucose dehydrogenase is reported. 2. N-Terminal-group analysis indicates only one type of N-terminal amino acid, methionine, to be present. 3. Peptide ;mapping' in conjunction with the amino acid analysis indicates that the subunits of the enzyme are similar if not identical. 4. The various kinetic classes of thiol group were investigated by reaction with 5,5'-dithiobis-(2-nitrobenzoate). 5. NAD(+), UDP-glucose and UDP-xylose protect the two rapidly reacting thiol groups of the hexameric enzyme. 6. Inactivation of the enzyme with 5,5'-dithiobis-(2-nitrobenzoate) indicates the involvement of six thiol groups in the maintenance of enzymic activity. 7. The pH-dependence of UDP-xylose inhibition of the enzyme was investigated. 8. The group involved in the binding of UDP-xylose to the protein has a heat of ionization of about 33kJ/mol and a pK of 8.4-8.6. 9. It is suggested that UDP-xylose has a cooperative homotropic effect on the enzyme.