C1 Strains Research Articles

Yersinia pseudotuberculosis in China.

Thirty strains of Yersinia pseudotuberculosis were isolated from rabbits (17 strains), wild rats (9 strains) and house rats (4 strains) in China between 1990 and 1993. The biochemical properties of these isolates were identical with those of Y. pseudotuberculosis and no special characteristics were found in these strains. Serologically, serogroups 4b and 5b were identical to isolates found in Japan, and a new serogroup 1c and unclassified strains have also been detected. The existence of virulence-associated properties were different among strains. The pYV plasmid was detected from 6 strains of 30 isolates. This report documents the presence of Y. pseudotuberculosis in China, providing important epidemiological information.

Classification of Lactobacillus plantarum by Restriction Endonuclease Analysis of Total Chromosomal DNA Using Conventional Agarose Gel Electrophoresis

A total of 17 Lactobacillus plantarum strains that originated from different environments and 24 reference strains were classified by performing a restriction endonuclease analysis of total chromosomal DNAs digested with Eco RI, Hind III, and Cla I, and the resulting patterns were visualized after the fragments were separated according to size by agarose gel electrophoresis. The patterns were analyzed by using the Pearson product moment correlation coefficient and the unweighted pair group algorithm with arithmetic averages. All but two l. plantarum strains formed a cluster that was separated from the reference strains at a similarity level of 29% (cluster 1). The two remaining L. plantarum strains (cluster 2) merged with cluster 1 at a level of similarity of 28%. The reference strains formed four additional clusters, and four reference strains were stragglers. Cluster 3 (three Lactobacillus pentosus strains) and cluster 4 (including Pediococcus acidilacti CCUG 32235T [T = type strain] and Lactobacillus fermentum ATCC 14931T) merged with cluster 1 at a level of similarity of 25%. Cluster 5 comprised and Lactobacillus reuteri strains, and cluster 6 contained the type strains of Lactobacillus amylovorus, Lactobacillus gasseri, and Lactobacillus vaginalis. Cluster 1 (L. plantarum) was divided into three subclusters, and this subdivision reflected to some extent certain phenotypic features of presumed ecological significance, including the ability to adhere to intestinal mucosa (subcluster 1c) and starch and glycogen degradation (subcluster la). A principal-component analysis significantly distinguished the strains belonging to different species. Also, the subcluster 1c strains could be separated from the rest of the L. plantarum strains. The results of restriction endonuclease analysis of total chromosomal DNA were found to be reproducible, and this method can be used to (i) differentiate between similar strains belonging to the same Lactobacillus species and group strains within a species, (ii) distinguish between strains of different Lactobacillus species, and (iii) place strains in specific Lactobacillus species.

Antigenic Relationships among Oral Actinomyces Isolates, Actinomyces naeslundii genospecies 1 and 2, Actinomyces howellii, Actinomyces denticolens, and Actinomyces slackii

Antigenic relatedness among human strains of oral Actinomyces and similar isolates from cattle has been analyzed by agglutination and immunoblotting. Whole cell agglutination placed A. viscosus serotype II, A. naeslundii serotypes II and III, Actinomyces NV, and strains from numerical taxomonic clusters C1, C2, C3, C4, and C6 into a single group. A. viscosus serotype I cross-reacted weakly with this group. A naeslundii serotype I strains and the cattle isolates Actinomyces denticolens and Actinomyces howellii were distinct. The agglutination results for A. slackii were equivocal. Immunoblots of cell wall extracts developed with non-absorbed sera showed cross-reactivity (23% to 90% antigenic similarity) among all of the strains tested, including A. israelii. The range of antigenic similarities among the group which included strains of A. viscosus serotype II, the A. naeslundii serotypes, and clusters C1, C2, C3, C4, and C6 was from 39% to 89%. Immunoblotting showed that A. howellii and A. denticolens were between 39% and 72% similar to A. naeslundii and A. viscosus. Absorption of antisera with A. israelii cell walls removed antibodies recognizing antigens common to Actinomyces and made the sera more specific. Immunoblotting with absorbed sera supported the grouping and separation of strains shown by agglutination. In some cases, serotypes could be included into a specific taxonomic cluster. A. naeslundii serotype II and Actinomyces NV most closely resembled cluster C1 strains, and A. naeslundii serotype III resembled cluster C1 strains, and A. naeslundii serotype I and A. viscosus serotype I were included into clusters C5 and C7, respectively. The results support a recent proposal that strains of A. viscosus serotype II, A. naeslundii serotypes II and III, and Actinomyces NV be included into A. naeslundii genospecies 2, that A. naeslundii serotype I should be designated A. naeslundii genospecies 1, and that A. viscosus serotype I should be retained distinct from A. naeslundii, as A. viscosus.

Behavior and brain neurotransmitters: Correlations in different strains of mice

Correlations of behavioral patterns in a social setting with catecholamines, serotonin, and several metabolites and precursors in three brain regions were examined in the DeFries H2, C1, and L1 strains of mice. In Experiment I, behavioral observations were recorded for two 15-min sessions in same-sex, same-strain pairs at about 65 days of age. In Experiment II, sex and strain groups were subdivided into 4% and 24% protein diet groups about 1 week before a second set of behavioral observations at about 120 days of age. Brain tissue content of neurotransmitters, precursors, and metabolites was determined by high-performance liquid chromatography after the second set of observations. Significant multivariate strain differences were shown for behavioral variables (both experiments) as well as concentrations of various neurochemicals. Strain H2 showed relatively high levels of locomotion, while rearing and social investigation were high in strain C1 and self-grooming in strain L1. Significant neurochemical differences were found in the following sets of variables: dopamine variables in the cortex, norepinephrine variables and serotonin variables in the combined diencephalon and midbrain, and norepinephrine and serotonin variables in the hindbrain. Effects of diet were found only on serotonin and tryptophan in the subcortical regions. Significant multivariate correlation with the behavioral variables was demonstrated for the catecholamines but not for serotonin. The results suggest that these strain differences in behavior may be mediated by catecholamine systems.

In vitro carotenogenesis by wild type and mutants of Phycomyces blakesleeanus

Cell extracts from shake cultures of the wild type and six mutant strains of Phycomyces converted [2- 14 C] MVA into carotenes, squalene and prenyl phosphates. Oxygen was required for the desaturation of phytoene. When compared with the wild type, cells extracts of carB and carR mutants are much less effective in phytoene dehydrogenation and lycopene cyclization, respectively. This confirms previous conclusions about the biochemical functions of the carB and carR genes, which were based on genetic and in vivo studies. CarA strain mutants accumulate, in vivo , much less β-carotene than the wild type. This correlates with a 10-fold decrease in carotenogenesis in vitro . The addition of retinol to incubations of cell extracts of the wild type and C2 strains stimulated β-carotene formation. Both carB and carR mutants show enhanced total carotenogenic activities in vitro and the carS mutant shows a higher β-carotene-synthesizing activity than the wild type. It is suggested that the feed-back regulatory mechanism known to control this pathway operates at the level of enzyme synthesis.

Diagnosis of Salmonella Bacteria: Antibodies Against Synthetic Salmonella O‐Antigen 8 for Immunofluorescence and co‐Agglutination using Sensitized Protein A‐Containing Staphylococci

An antiserum against the synthetic disaccharide abequose 1 leads to 3 alpha rhamnose (AR), representative of Salmonella O-antigen 8, coupled to bovine serum albumin (BSA) was used for diagnosis of Salmonella bacteria by indirect immunofluorescence (IFL) and by co-agglutination (COA) using sensitized protein A-containing staphylococci. Among the 1150 enteric bacteria tested in IFL, the antiserum correctly identified all 99 Salmonella serogroup C2 and C3 bacteria with O-antigen 8. No fluorescence was seen with 484 Salmonella bacteria belonging to other serogroups or 567 non-Salmonella enteric bacteria. The anti-AR-BSA serum was favourable as compared to a conventional Salmonella factor O8 serum as regards both titre and specificity. In the COA test, all 22 Salmonella serogroup C2 and C3 strains agglutinated strongly and within seconds, whereas no agglutination could be seen when 93 Salmonella bacteria representing other serogroups were tested.

Morphology of the bacteriophages of lactic streptococci.

Electron microscope studies have been made of a number of phages of lactic streptococci, seven of which were phages of Streptococcus lactis C10. Two of the phages are thought to be identical; five have been classified by the method of Tikhonenko as belonging to group IV (phages with noncontractile tails) with type III tail plates; one belongs to group V (phages with tails possessing a contractile sheath). Both prolate polyhedral heads and isometric polyhedral heads are represented among the group IV phages. The phage drc3 of S. diacetilactis DRC3 has been shown to have similar structure to the group IV phages of S. lactis C10 with prolate polyhedral heads. The phages ml1, hp, c11, and z8 of the S. cremoris strains ML1, HP, C11, and Z8, respectively, were shown to belong to the group IV phages with type III tail plates by the method of Tikhonenko. All had octahedral heads and tended to be larger than most of the other phages studied.

Morphology of the Bacteriophages of Lactic Streptococci

Electron microscope studies have been made of a number of phages of lactic streptococci, seven of which were phages of Streptococcus lactis C10. Two of the phages are thought to be identical; five have been classified by the method of Tikhonenko as belonging to group IV (phages with noncontractile tails) with type III tail plates; one belongs to group V (phages with tails possessing a contractile sheath). Both prolate polyhedral heads and isometric polyhedral heads are represented among the group IV phages. The phage drc3 of S. diacetilactis DRC3 has been shown to have similar structure to the group IV phages of S. lactis C10 with prolate polyhedral heads. The phages ml1, hp, c11, and z8 of the S. cremoris strains ML1, HP, C11, and Z8, respectively, were shown to belong to the group IV phages with type III tail plates by the method of Tikhonenko. All had octahedral heads and tended to be larger than most of the other phages studied.

SOME FACTORS WHICH GOVERN PLAQUE FORMATION BY LACTIC STREPTOCOCCAL BACTERIOPHAGE.: I. SEED LAYER REQUIREMENTS

SummaryA study was conducted of factors which may influence the accuracy of the plaque count obtained by the double-agar layer method as applied to lactic streptococcal bacteriophage. Host cell cultural media were skimmilk or hydrolyzed milk protein broth (Sobol's). Streptococcus lactis strains ML3, C10, C2 and Streptococcus cremoris strains C3, KH, R1, US3 and the homologous bacteriophages were used. Plaque formation on Trypticase Soy Agar was generally enhanced by: (a) modification of the cultural media or the seed layer agar by the addition of CaCl2, phenylalanine, proline, riboflavin, niacin, calcium pantothenate, and biotin; (b) using a six-hr culture of host cells rather than cells incubated for 18 or 24 hr; and (c) selection of the proper serial transfer system for reactivating the host cells from a frozen or lyophilized state. Sobol's broth yielded lower plaque counts than skimmilk irrespective of the modifications used. Responses to plaque enhancement factors were influenced by species and strain differences of S. lactis and S. cremoris. In general, strains of S. cremoris had a more exacting requirement for calcium, media enrichment, and length of incubation of host cells than S. lactis strains.

THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA

Absorption curves have been obtained in the spectral region of 450 to 900 mmicro for the water soluble cell juice of four species of photosynthetic bacteria, Spirillum rubrum (strain S1), Rhodovibrio sp. (strain Gaffron), Phaeomonas sp. (strain Delft), and Streptococcus varians (strains C11 and orig.). These curves all show maxima at 790 and 590 mmicro due to bacteriochlorophyll, whose highest band, however, occurs at 875, 855, or 840 mmicro depending on the species. The bacteria that appear red rather than brown have a band at 550 mmicro due to a carotinoid pigment. An absolute absorption curve of bacteriophaeophytin has maxima at 530 and 750 mmicro. The extraction of cell juice by supersonic vibration does not change the position of the absorption bands or of the light absorbing capacity of the pigment.