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PubMed1964

RECIPIENT ABILITY OF SALMONELLA TYPHOSA IN GENETIC CROSSES WITH ESCHERICHIA COLI.

Johnson, E. M. (Walter Reed Army Institute of Research, Washington, D.C.), Stanley Falkow, and L. S. Baron. Recipient ability of Salmonella typhosa in genetic crosses with Escherichia coli. J. Bacteriol. 87:54-60. 1964.-Salmonella typhosa strain 643WS(r) was mated with Escherichia coli Hfr strains W1895 and Hayes, with single marker selection for the E. coli genes lac(+) (lactose utilization) and ara(+) (arabinose utilization). Four classes of Salmonella hybrids were obtained, each class possessing one marker derived from one E. coli parent. In a series of eight genetic crosses, in which each hybrid class was remated with each of the Hfr strains, recipient ability of the hybrids was increased only when their substituted E. coli genetic section matched the lead region of the Hfr chromosome. Data obtained from replica plating indicated that the S. typhosa 643WS(r) population is probably homogeneous with respect to its initial ability to mate with E. coli. Transfer of the F-lac element was found to occur only slightly less efficiently from an E. coli F' donor to S. typhosa than it did to an E. coli F(-) strain. This indicated that E. coli is able to conjugate almost as effectively with S. typhosa as it does intraspecifically. However, failure to detect beta-galactosidase production by merozygotes derived from an E. coli Hfr W1895 x S. typhosa mating indicated that transfer of chromosomal lac(+) may be impaired.

Arabinose↗
PubMed1964

CELL WALL REPLICATION IN SALMONELLA TYPHOSA.

Changes in the fluorescence of the cell wall of Salmonella typhosa (TY2 W) were studied during growth after direct labeling with fluorescein conjugated homologous or "anti-O" globulins. Fluorescence decreased evenly with culture growth and cell division, but the addition ofchloramphenicol resulted in large, nondividing cells that showed increasing interruption of fluorescence of the wall marker. The process thus differs from the equatorial origin and discrete hemispherical addition of new wall previously described in Streptococcus pyogenes. These findings, in addition to demonstrating the formation of new wall in the presence of chloramphenicol, appear consistent only with the concept that wall replication in the salmonellas occurs by means of diffuse intercalation of new materials among old.

Cell Biology↗
PubMed1970

Conservation and transfer of Escherichia coli genetic segments by partial diploid Hfr strains of Salmonella typhosa.

Heterozygous, partial diploid hybrids were obtained in a Salmonella typhosa Hfr strain by using it as the recipient in a mating with the Escherichia coli Hfr donor WR2004 (O...proA...leu). Three of these S. typhosa Hfr hybrids were observed to mobilize and transfer the diploid E. coli genes, at high frequencies, to an E. coli recipient. The gradient of transfer frequencies of E. coli markers from these S. typhosa Hfr hybrids was similar to that observed with E. coli Hfr WR2004, from which they were derived. Interrupted matings with one of these S. typhosa Hfr hybrids, designated WR4272, showed the entry times for the proA, thr(-)leu, and argB E. coli diploid markers to be identical to the times obtained for these markers with E. coli Hfr WR2004. Also, the pattern of unselected inheritance of the diploid E. coli markers of S. typhosa Hfr hybrid WR4272 was similar to that observed with the chromosomal markers of E. coli Hfr WR2004. It was concluded that S. typhosa Hfr hybrid WR4272 contains, in addition to its Salmonella genome, a physically continuous E. coli chromosomal segment which is genetically complete from proA to at least the strA locus. The two other S. typhosa Hfr hybrids, on the basis of transmission frequency gradients, appeared to contain a continuous E. coli diploid segment complete from proA through the fuc locus. Other classes of S. typhosa Hfr hybrids, derived from mating with E. coli Hfr WR2010 (O...tna...xyl), were also observed to transfer E. coli genes at high frequency.

Chromosome Mapping↗
PubMed1962

EPISOMIC ELEMENT IN A STRAIN OF SALMONELLA TYPHOSA.

Falkow, Stanley (Walter Reed Army Institute of Research, Washington, D.C.) and L. S. Baron. Episomic element in a strain of Salmonella typhosa. J. Bacteriol. 84:581-589. 1962.-An episomic element, F(0)-lac(+), has been identified in a strain of Salmonella typhosa isolated from a natural habitat. The F(0)-lac(+) element is transferred at high frequency as a single unit of transmission and replication without linkage to any other genetic character. Cells receiving F(0)-lac(+) are heterogenotes as if F(0)-lac(+) is not integrated as part of the linear structure of the chromosome, but rather replicates autonomously or in some other association with the genome. Evidence from complementation tests and transduction experiments is presented that the lac genes carried by F(0) are identical or at least markedly similar to the lac genes of Escherichia coli K-12. The F(0) transmission factor cannot be precisely identified but it does not appear to be phage or colicin. F(0) does exhibit mutual repression with the sex factor, F, of E. coli, and immunological experiments indicate some relationship between F and F(0).

Journal Article↗
PubMed1962

Vi-negative strains of Salmonella typhosa: attempts to induce W-V reversion and the use of non-Vi strains in evaluating typhoid vaccines.

Tully, Joseph G. (Walter Reed Army Institute of Research, Washington, D.C.) and Julius A. Currie. Vi-negative strains of Salmonella typhosa: attempts to induce W-V reversion and the use of non-Vi strains in evaluating typhoid vaccines. J. Bacteriol. 84:747-753. 1962.-Repeated attempts have been made to detect reversion of several W-form Salmonella typhosa strains to Vi antigen-containing cultures. Passage of the O-901, H-901, and Ty2W cultures through various mouse strains did not result in the recovery of V-form typhoid bacilli. Rabbits immunized repeatedly with non-Vi strains of typhoid bacilli, or with W cultures successively passed through mice, did not respond with Vi antibody formation. Attempts also were made to detect reversion of non-Vi strains passed in broth and plate cultures to which heat-killed Vi antigen-containing strains had been added. No evidence was obtained that the selection of Vi-containing cultures had been enhanced. The non-Vi typhoid strains employed in this study thus appeared to be stable W-form cultures. Viable-cell vaccines and acetone-killed and dried (AKD) vaccines of V- and W-form S. typhosa were compared in active mouse protection tests against intraperitoneal and intracerebral challenges with V- and W-form typhoid strains. Only Vi-containing cultures effectively protected mice against virulent V-form challenges, regardless of the route utilized. Greater quantities of both viable-cell and AKD vaccines prepared from non-Vi strains were required for protection against V- as well as W-form S. typhosa challenges.

Animals↗
PubMed1972

Enhanced toxicity for mice of vincristine and other chemotherapeutic agents with Salmonella typhosa endotoxin and Pseudomonas aeruginosa.

The toxicity of Salmonella typhosa 0901 W endotoxin for BALB/c mice was potentiated by the administration of 375 mg of cyclophosphamide per kg, 16 mg of daunomycin per kg, 80 mg of methotrexate per kg, 8 mg of pactamycin per kg, 20 mg of polyinosinic-polycytidylic acid per kg, 1,000 mg of procarbazine per kg, and 1 or 4 mg of vincristine per kg. l-Asparaginase (20,000 units per kg) failed to potentiate endotoxin. Sedation following administration of 45 mg of pentobarbital per kg was prolonged in mice that had received 20,000 units of l-asparaginase per kg, 4 mg of daunomycin per kg, 120 mg of methotrexate per kg, 8 mg of pactamycin per kg, 10 mg of polyinosinic-polycytidylic acid per kg, 500 mg of procarbazine per kg, 2 mg of vincristine per kg, 2 mg of endotoxin per kg, or multiple doses of endotoxin. Mice pretreated with multiple endotoxin doses experienced a significant reduction in their lethal responses due to vincristine-endotoxin combinations; however, endotoxin-pretreated mice were more susceptible to vincristine alone than were normal mice. Simultaneous administration of 1 or 2 mg of vincristine per kg and 1 mg of endotoxin per kg produced greater lethality than sequential regimens. Pretreatment of mice with 65 mg of phenobarbital per kg on 4 consecutive days protected against vincristine-endotoxin combinations. Liver homogenates prepared from mice exposed previously to vincristine were capable of inactivating endotoxin. Vincristine lethality was increased by simultaneous administration of heat-killed cells of Pseudomonas aeruginosa isolated from mouse feces.

Animals↗
PubMed1972

Lytic replication of coliphage lambda in Salmonella typhosa hybrids.

Hybrids between Escherichia coli K-12 and Salmonella typhosa which conserved a continuous K-12 chromosomal diploid segment extending from pro through ara to the strA locus were sensitive to plaque formation by wild-type lambda. These partially diploid S. typhosa hybrids could be lysogenized with lambda and subsequently induced to produce infectious phage particles. When the K-12 genes were segregated from a lysogenic S. typhosa hybrid, phage-productive ability was no longer detectable due to loss of a genetic region necessary for vegetative replication of lambda. However, lambda prophage was shown to persist in a quiescent state in the S. typhosa hybrid segregant with phage-productive ability being reactivated after replacement of the essential K-12 lambda replication region. Low-frequency transduction and high-frequency transduction lysates containing the gal(+) genes of S. typhosa were prepared by induction of lambda-lysogenic S. typhosa hybrids indicating that the attlambda site is chromosomally located in S. typhosa in close proximity to the gal locus as in E. coli K-12. After propagation in S. typhosa hybrids, lambda was subject to restriction by E. coli K-12 recipients, thus establishing that S. typhosa does not perform the K-12 modification of lambda deoxyribonucleic acid. Hybrids of S. typhosa, however, did not restrict lambda grown previously on E. coli K-12. The K-12 genetic region required for lambda phage production in S. typhosa was located within min 66 to min 72 on the genetic map of the E. coli chromosome. Transfer of an F-merogenote encompassing the 66 to 72 min E. coli chromosomal region to lambda-insensitive S. typhosa hybrids enabled them to replicate wild-type lambda. The lambda-insensitive S. typhosa hybrid, WR4255, which blocks lambda replication, can be mutagenized to yield mutant strains sensitive to lambdavir and lambdaimm434. These WR4255 mutants remained insensitive to plaque formation by wild-type lambda.

Chromosome Mapping↗
PubMed1977

Non-typhosa Salmonella species: analysis of 94 isolations.

Despite rigorous control measures by local, state, and federal health agencies, salmonellosis continues to be one of America's most troublesome epidemiological problems. Salmonellosis, a reportable disease, is estimated to infect more than two million persons each year. However, only 10 to 12 percent of cases are actually reported. To study the impact of salmonellosis at Howard University Hospital, the authors made a statistical analysis of non-typhosa Salmonella isolated during a two-year period. The study emphasizes the epidemiological aspects of, and useful isolation and identification techniques for, non-typhosa Salmonella.

Black People↗
PubMed1971

Isolation of circular deoxyribonucleic acid from Salmonella typhosa hybrids obtained from matings with Escherichia coli Hfr donors.

Heterozygous, partial diploid Salmonella typhosa hybrids obtained from matings with Escherichia coli K-12 Hfr strains were observed to contain supercoiled, circular deoxyribonucleic acid (DNA) when examined by the dye-buoyant density method. Examination of one such S. typhosa hybrid after its loss, by segregation, of the inherited E. coli genetic markers revealed a concurrent loss of its supercoiled circular DNA. Subsequent remating of this segregant with various E. coli Hfr strains resulted in the reappearance of the circular DNA. Molecular weight determinations of circular DNA molecules isolated from a number of S. typhosa partial diploid hybrids were made by sucrose density gradient ultracentrifugation and electron microscopy. These studies revealed a range of molecular sizes among the various hybrids examined, but each hybrid exhibited only a single characteristic size for its contained circular DNA. The range of size is consistent with the presence in each hybrid of a different length of E. coli chromosome. It was concluded that the E. coli Hfr genetic segments transferred to these S. typhosa hybrids were conserved, in the diploid state, in the form of supercoiled, circular DNA molecules.

Centrifugation, Density Gradient↗
PubMed1971

Enhanced toxicity for mice of combinations of antibiotics with Escherichia coli cells or Salmonella typhosa endotoxin.

Enhanced lethality for BALB/c mice has been observed after the administration of Salmonella typhosa endotoxin with either actinomycin D, cycloheximide, or nogalamycin. The dose of actinomycin D required to kill half of the mice (LD(50)) was 0.8 mg/kg in normal animals, 0.35 mg/kg in mice administered 0.08 mg of endotoxin per kg, and 0.28 mg/kg in mice administered 0.2 mg of endotoxin per kg. The LD(50) of endotoxin in normal mice was 12 mg/kg and in mice given 0.4 mg of actinomycin D per kg was 0.067 mg/kg. The LD(50) of actinomycin D in mice administered 1.8 x 10(8) live Escherichia coli cells per kg or 1.8 x 10(9) heat-killed E. coli cells per kg was reduced to 0.4 mg/kg. The LD(50) of cycloheximide was 181 mg/kg in normal animals and 28 mg/kg in mice administered 4 mg of endotoxin per kg. The LD(50) of endotoxin in mice given 120 mg of cycloheximide per kg was 0.02 mg/kg. Enhanced lethality due to various combinations of cycloheximide and endotoxin was abolished by pretreatment of mice with endotoxin. The LD(50) of nogalamycin was 21 mg/kg in normal mice and 13 mg/kg in mice receiving 1 mg of endotoxin per kg.

Animals↗
PubMed1960

Studies on infection and immunity in experimental typhoid fever. I. Typhoid fever in chimpanzees orally infected with Salmonella typhosa.

A disease resembling human typhoid fever has been induced by feeding live cultures of Salmonella typhosa to young chimpanzees, thus confirming the classical reports of Grünbaum and of Metchnikoff and Besredka. Detailed clinical observations, results of stool and blood cultures, and serological studies have confirmed the impression that the disease produced in chimpanzees closely resembles the mild form of human typhoid fever frequently seen in childhood. Gross and histologic examination of intestines, mesenteric lymph nodes, liver, spleen, and other organs of orally infected chimpanzees has demonstrated that the pathological findings are essentially indistinguishable from those seen in mild typhoid fever in man. The clinical spectrum of disease seen in chimpanzees ranged from moderately severe illness, through transitory illness, to afebrile infection with or without bacteriemia (but invariably with an antibody response), occasionally leading to the development of persisting biliary infection and the carrier state. Thus the range of illness observed in chimpanzees resembled that seen in man, except that the severe and complicated forms of typhoid fever were not observed in the chimpanzee. A reason for this difference is proposed and discussed. In contrast to the limitations imposed upon the interpretation of human epidemiologic observations, it has been possible to demonstrate in the chimpanzee that clinical variation in disease pattern from animal to animal may occur despite the administration of the same dose of the same bacterial strain simultaneously to an entire group of animals under study; in other words, variation in clinical pattern is dependent on inherent, non-specific host factors as well as on dose, strain or preceding state of immunity. Variation in dose and in challenge strain of S. typhosa employed also appeared to have an effect upon the likelihood of producing febrile as against afebrile infection in chimpanzees. The dose required to produce clinical disease, even with the more virulent strain, was excessively large compared to what is believed to be the dose required to produce illness in man; the limitations of this assumption, and suggested explanations for the findings, are discussed. The production of the spectrum of typhoid fever in the chimpanzee has made possible the study of basic problems in this disease which are not amenable to definitive study through the use of prevailing laboratory techniques.

Animals↗
PubMed1978

Factors influencing the secondary immune response in rabbits to Salmonella typhosa.

The characteristics of the primary response, as well as those of the secondary response, to different doses of Salmonella typhosa when elicited at two different time intervals were analysed. The antibody response demonstrates that the size of the primary dose, and the size of the secondary dose, have significant effect on the subsequent synthesis of the secondary IgM and IgG antibody response to both 'H' and 'O' antigens. The time elapsed between the primary and secondary response tends to decrease the IgG response. Due to the high immunogenicity of the 'H' antigen the maximum IgG levels were reached within the range of doses used. These high levels of antibody inhibited the secondary IgM response by a feedback mechanism. Enhanced or equivalent response of predominant anti 'O' IgM system was recorded.

Animals↗
PubMed1975

Vi antigen from Salmonella typhosa and immunity against typhoid fever. 11. Safety and antigenicity in humans.

Safety and antigenicity of a purified preparation of Salmonella typhosa Vi antigen was evaluated in human volunteers. Dosages of Vi antigen at 25, 50, and 100 mug were less toxic than U.S. standard typhoid vaccine (lot 6A) containing 5 X 10(8) bacteria per dosage. Vi antigen in comparison with the standard typhoid vaccine induced higher hemagglutinating antibody but lower bactericidal antibody responses.

Antibody Formation↗
PubMed1956

Studies on the O antigen of Salmonella typhosa. V. Enhancement of antibody response to protein antigens by the purified lipopolysaccharide.

Quantitative studies have demonstrated that a purified lipopolysaccharide (endotoxin) derived from the O-901 strain of Salmonella typhosa markedly enhanced the antibody response of rabbits when given separately or in conjunction with protein antigens. The augmentation of antibody levels varied from 2- to 40-fold with the number of injections, the dosage of antigen and endotoxin, and the route of administration. This antibody-enhancing property was found to be common to a broad group of endotoxins from Gram-negative bacilli and was not restricted to the lipopolysaccharide derived from S. typhosa. Factors affecting this enhancement were investigated, and data are presented which indicate that host susceptibility to endotoxin is a prerequisite for elevation of antibody levels; the intact lipopolysaccharide, as isolated, might not be essential for this activity; and the rate of clearance of antigen from the circulation of rabbits was accelerated when endotoxin was given in conjunction with protein. The data obtained are discussed in relation to postulated mechanisms on the antibody-enhancing action of endotoxin.

Animals↗