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Biomedical subjects

S D Henriksen

Publications and source records attributed to S D Henriksen.

At least 19 recordsLinked to original sources
PubMed1979

Genetic transformation in Streptococcus sanguis. Spontaneous and induced competence of selected strains.

Nine strains of Streptococcus sanguis were examined for competence in genetic transformation with streptomycin resistance (str-r) as marker. Eight strains belonged to serogroup H and one to the newly-described serogroup W. Seven of the strains, one of which was the reference strain NCTC 7868 (strain Challis), were competent with str-r DNA from strain Challis. Strains NCTC 9124 (strain Wicky) and 480 were incompetent. The efficiency of transformation was examined in four different media. Use of Todd Hewitt broth gave frequencies of transformants as high as the more complex media. Addition of serum to the transformation media was not essential for the development of competence. The presence of a competence factor (CF) in the culture filtrate of strain Challis was confirmed. The factor transferred strain Wicky to competence with a great variation in the number of transformants and had no influence on strain 480. On the other hand, this spontaneously incompetent strain became competent after addition of culture filtrate from the competent strain 13b, in contrast to Wicky which now remained incompetent. Thus, it is suggested that several factors are involved in the induction of competence of S. sanguis.

Bacterial Proteins↗
PubMed1977

Relationship of Neisseria elongata subsp. Glycolytica to other members of the family Neisseriaceae.

Neisseria elongata subsp. glycolytica strain 6171/75 is closely similar to the type strain of N. elongata, M2, as regards DNA base composition, fatty acid content and electrophoretic mobility of two glutamate dehydrogenases, one of which showed a reaction of identity with the corresponding enzyme from M2 in double immunodiffusion in agar. The strain showed genetic homologies with strain M2 in genetic transformation at a level suggesting species identity, and with N. meningitidis at a lower level. No affinity to Moraxella species or "false neisseriae" was demonstrated, with the exception of a production of a few transformants in the 6171/75 recipient by DNA from Kingella kingae. The strain showed the same pattern of associated variation of colony type, fimbriation and competence in transformation as that found in other Neisseria and Moraxella species. After continuous subcultivation for some time some clones of the strain appeared to have lost the ability to produce acid from glucose.

Clone Cells↗
PubMed1976

Further studies of twitching Streptococcus sanguis isolated from the human throat. Isolation of strains with a new antigen.

alpha-haemolytic streptococci, classified as Streptococcus sanguis, with spreading growth due to twitching mobility were isolated from 41% of 121 swab cultures from the human pharynx. Sixty-five out of 70 isolates with spreading growth belonged to Lancefield's group H, while 5 isolates constituted a new serological entity. None of 159 non-spreading alpha-haemolytic streptococci isolated from the same cultures possessed either of these antigens. An examination of strains of types I, II and I/II described by Washburn et al., in the group H antisera employed in the present study indicated that type I and type I/II differ from one another in the degree of cross-reactivity with anti-type II serum. (The type II antigen was not demonstrated in any of the isolated strains). We support the opinion that type II should not be considered as S. sanguis.

Antigens, Bacterial↗
PubMed1976

Transforamtion of twitching strains of Streptococcus sanguis.

Ninety-five strains of S. sanguis, 90 of which were twitching, were screened for competence in transformation with DNA from the "Challis" strain. Seventy-two strains, 68 of sero-group H and 4 of the provisional group 10043, were competent. Fourteen of the competent strains and all strains which appeared to be incompetent were tested with DNA from 3 other strains. The 14 competent strains were transformed by all the 3 DNAs. One of the apparently incompetent strains was transformed by autologous DNA only. Among 8 reference strains (including ATCC 10577, Type II of Washburn et al.) 5 were competent. Three of these did not show spreading or twitching. Among 16 non-spreading strains of alphahaemolytic streptococci which did not possess either the H or the 10043 group antigen, only one showed competence. The results indicate that twitching mobility is not a prerequisite for competence.

Culture Media↗
PubMed1976

Haemagglutination of twitching Streptococcus sanguis.

Among 86, mostly twitching, polarly fimbriated strains of Streptococcus sanguis, 55 agglutinated guinea pig erythrocytes (GPE) after cultivation in Todd-Hewitt broth (TH), and 21 strains agglutinated GPE only after growth in TH with 10% horse serum (THS). Two of the positive strains were non-twitching and unfimbriated. Ten strains failed to haemagglutinate. Among 5 twitching strains belonging to the 10043 group, 3 agglutinated GPE after growth in TH and 2 only after growth in THS. Among 35 non-twitching strains of alpha-haemolytic streptococci, only 6 agglutinated GPE after growth in TH, and among 8 negative strains which were tested after growth in THS, only 1 agglutinated GPE. Tests using 6 different kinds of erythrocytes (guinea pig, rabbit, sheep, horse, chicken, human) revealed that differences between these were slight only. The results do not indicate that there is an absolute association between twitching and haemagglutination in S. sanguis. The haemagglutination of S. sanguis was not mannose-sensitive.

Animals↗
PubMed1975

A fimbriated strain of Pasteurella multocida with spreading and corroding colonies.

A strain identified as Pasteurella multocida ("dog type") grew on blood agar with spreading and corroding colonies; it was found to be fimbriated. A non-fimbriated variant of the strain which did not produce spreading and corroding colonies was isolated. The fimbriated strain regularly formed surface growth by static incubation in broth. The mode of surface translocation of this strain appeared to be twitching.

Female↗
PubMed1975

Twitching motility and possession of polar fimbriae in spreading Streptococcus sanguis isolates from the human throat.

A collection of 19 strains of alpha haemolytic streptococci, isolated from throat swabs and characterized by production of spreading zones around colonies on blood agar, was found to constitute a very homogeneous group with morphological, physiological and biochemical characters corresponding to those of streptococci of ser-group H, or Streptococcus sanguis, and they all appeared to possess the group H antigen. They all had a common agglutinogen and, in addition, heterogeneous agglutinogens. The spreading growth, which appears to be a common property of S. sanguis, was due to twitching motility, and the spreading cultures possessed polar fimbriae. tneither twitching motility nor the possession of polar fimbriae have been observed in gram-positive bacteria before.

Agglutination Tests↗