Emergence of competence (for transformation) of three Hemophilus species in a chemically defined environment

PORCINE CONTAGIOUS PLEUROPNEUMONIA. II. STUDIES OF THE PATHOGENICITY OF THE ETIOLOGICAL AGENT, HEMOPHILUS PLEUROPNEUMONIAE

Hemophilus pleuropneumoniae is highly pathogenic for swine when given intranasally. As few as 100 organisms induce characteristic porcine contagious pleuropneumonia (PCP) and, when as many as one-half million are given, the infection usually proceeds to a fatal termination. While the organism is highly pathogenic when introduced by way of the respiratory tract, it is innocuous when given subcutaneously even in large numbers. Swine that have been inoculated subcutaneously are rendered solidly immune to infection with H. pleuropneumoniae intranasally. The marked pathogenicity of H. pleuropneumoniae for swine has been contrasted with the lack of pathogenicity of another swine Hemophilus, H. influenzae suis. It has been pointed out that, in its high degree of pathogenicity, in its pneumotropism, and in its immunogenicity by a non-respiratory route of inoculation, H. pleuropneumoniae appears to resemble certain viruses more than it does a bacterium.

HEMIN BIOSYNTHESIS IN HAEMOPHILUS

White, David C. (The Rockefeller Institute, New York, N.Y.) and S. Granick. Hemin biosynthesis in Haemophilus. J. Bacteriol. 85:842-850. 1963.-Hemin-independent Haemophilus species have been shown to form hemin by the classical hemin biosynthetic pathway. Three distinct species of Haemophilus [H. influenzae, H. aegyptius, and H. canis (H. haemoglobinophilus)] all lost the enzymatic capacities to convert delta-aminolevulinic acid to protoporphyrin, which accounts for their dependence on hemin for growth. The strain of H. aegyptus tested cannot form hemin from protoporphyrin, can be transformed with deoxyribonucleic acid (DNA) from H. influenzae, and the resultant progeny have the enzymatic activity to convert protoporphyrin to hemin. Attempts to transform these species to hemin independence with DNA from hemin-independent H. parainfluenzae are unsuccessful under conditions where streptomycin resistance is readily transformed.

INCORPORATION OF DEOXYRIBONUCLEIC ACID IN THE BACILLUS SUBTILIS TRANSFORMATION SYSTEM

Young, F. E. (Western Reserve University Cleveland, Ohio) and John Spizizen. Incorporation of deoxyribonucleic acid in the Bacillus subtilis transformation system. J. Bacteriol. 86:392-400. 1963.-The optimal conditions for the incorporation of deoxyribonucleic acid (DNA) were studied. In competent cells, the irreversible binding of DNA was influenced by temperature, hydrogen ion concentration, and aeration. Divalent cations, such as barium, strontium, calcium, or magnesium, were required. Under suboptimal environmental conditions and with metabolic inhibitors, the process of transformation was decreased to a greater extent than was incorporation of DNA. Under conditions of phosphate depletion, the incorporation of P(32) increased. However, the frequency of transformation decreased. This inducible process was not related to competence.

PORCINE CONTAGIOUS PLEUROPNEUMONIA. 3. INTERRELATIONSHIP OF HEMOPHILUS PLEUROPNEUMONIAE TO OTHER SPECIES OF HEMOPHILUS: NUTRITIONAL, METABOLIC, TRANSFORMATION, AND ELECTRON MICROSCOPY STUDIES

Hemophilus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP) is an encapsulated organism that has the metabolic features of the parainfluenza group of Hemophilus in that it requires DPN but not hemin for growth. Its formation of nitrate reductase cytochrome a₁ and non-physiologically reducible cytochrome c₁ in the stationary phase, together with its requirement of electron transport through oxidases for growth are typical of non-hemin-requiring Hemophilus species. It has the closest genetic homology, judged from the capacity of its DNA to induce transformation to streptomycin resistance, with H. parasuis but can be differentiated from this organism on the basis of its growth in defined medium and its marked and characteristic pathogenicity for swine.

Action of haemophilus endodeoxyribonuclease on biologically active deoxyribonucleic acid

An enzyme similar to that described by Smith and Wilcox (15) for Haemophilus influenzae which attacks foreign deoxyribonucleic acid (DNA) but not its own has been isolated and purified from H. parainfluenzae. The enzyme degrades foreign DNA to limited sizes and can destroy the transforming activity of H. influenzae and Bacillus subtilis DNA. The enzyme can also destroy the biological activity of H. influenzae phage and prophage DNA. On the other hand, the H. influenzae endodeoxyribonuclease can destroy the transforming activity of H. parainfluenzae DNA but not its own DNA. It also attacks B. subtilis DNA and its transforming activity.

Defined nongrowth media for stage II development of competence in Haemophilus influenzae

The composition of a defined nongrowth medium used in stage II development of competence of Haemophilus influenzae affects the course of this development. The development of competence in two nongrowth media, M-IV and M-V, is rapid, logarithmic, and independent of the cell concentration. This last property indicates that there is probably no transfer of a competence factor from competent to noncompetent cells, in contrast to results reported for other organisms. Levels of competence reached in these completely defined media are such that 1 to 5% of the cells are transformed in the presence of an excess of marked deoxyribonucleic acid. The method of evaluating competence, which depends on the frequency of multiple independent transformations, has been reexamined. This and other methods are compared on samples taken from a culture during development of competence.

Formation of a functional electron transport system during growth of penicillin-induced spheroplasts of Haemophilus parainfluenzae

Wright, Elizabeth A. (University of Kentucky College of Medicine, Lexington), and David C. White. Formation of a functional electron transport system during growth of penicillin-induced spheroplasts of Haemophilus parainfluenzae. J. Bacteriol. 91:1356-1362. 1966.-Penicillin in a lactose medium can be used to cause the formation of spheroplasts in Haemophilus parainfluenzae. The resulting spheroplasts grew under conditions which produced rapid formation of the electron transport system in the normal bacteria. The following elements that are incorporated into a functionally active electron transport system were formed in spheroplasts: formate and l-lactate dehydrogenases, 2-demethyl vitamin K(2), cytochromes b(1) and c(1), and the cytochrome oxidases. The catabolic enzymes aldolase, glyceraldehyde-3-phosphate dehydrogenase, and malic dehydrogenase showed slight increases in activity. These experiments indicated that spheroplasts can form a fully functional electron transport system essentially similar to that formed during normal growth. The various components of the electron transport system were formed at different rates in the growing spheroplasts.

Development of competence of Haemophilus influenzae

Spencer, Hugh T. (The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.), and Roger M. Herriott. Development of competence of Haemophilus influenzae. J. Bacteriol. 90:911-920. 1965.-A chemically defined nongrowth medium was developed for the induction of competence of Haemophilus influenzae by a stepdown procedure. Cells grown logarithmically in Heart Infusion Broth became competent after being transferred to a medium which consisted of amino acids, sodium fumarate, and inorganic salts. Chloramphenicol (2 mug/ml) or l-valine (1 mug/ml) in the nongrowth medium inhibited development of competence. The inhibitory action of l-valine was reversed by comparable concentrations of l-isoleucine. Kinetic studies of the development of competence showed a variable capacity of competent cells to take up deoxyribonucleic acid and reaffirmed earlier findings that competence was not transmissible in H. influenzae. Addition of nicotinamide adenine dinucleotide, thiamine, calcium pantothenate, uracil, and hypoxanthine to the medium for competence resulted in a minimal growth medium in which reduced levels of competence were developed.