Hematin--requiring plasmodial myxomycete

Daniel, John W. (University of Wisconsin, Madison), Jacqueline Kelley, and Harold P. Rusch. Hematin-requiring plasmodial myxomycete. J. Bacteriol. 84:1104-1110. 1962.-The myxomycete Physarum polycephalum, previously shown to require chick embryo extract for growth on a partially defined, soluble medium, grows as well if hematin or certain hemoproteins are substituted for the embryo extract. Hematin is also required as a growth factor if the organism is grown on a synthetic medium. Of the variety of porphyrins tested only iron protoporphyrin IX is utilized for growth by P. polycephalum. Protoporphyrin IX is inactive. Protein-bound iron porphyrin is active at one-tenth the concentration of free hematin. Although hematin completely replaces embryo extract, the extract activity has properties not characteristic of hematin or the hemoproteins tested: ladility to light and rapid plasmodial uptake.

Respiratory systems in the hemin-requiring Haemophilus species

White, D. C. (Rockefeller Institute, New York, N.Y.). Respiratory systems in hemin-requiring Haemophilus species. J. Bacteriol. 85:84-96. 1963.-If grown in Levinthal's medium or in proteose peptone medium with excess hemin, Haemophilus influenzae, H. aegyptius, and H. canis (H. haemoglobinophilus) form an electron-transport system consisting of six cytochromes and two respiratory flavoproteins. In proteose peptone, these species can greatly modify the composition of their electron-transport complex. With anaerobic incubation in the presence of nitrate, they produce increased amounts of cytochrome c(1) and the cytochrome oxidases a(1) and o. This anaerobic pattern is greatly exaggerated by growth under carbon monoxide, in which case large concentrations of cytochrome oxidase are produced. In the presence of the inhibitor secobarbital or of growth-limiting amounts of hemin, intermediate amounts of cytochromes and respiratory flavoproteins are formed. When only small amounts of hemin are present, these species grow but form no detectable cytochrome system. Catalase is the only hemoprotein found. Under these conditions, the addition of glucose induces the formation of a lactate oxidase flavoprotein if the system is incubated aerobically. This cytochromeless state also occurs when these species are grown in KCN or anaerobically without nitrate and with excess hemin. The ability of these species to modify the composition of the electron-transport system strongly suggests that this function unit is formed from individual components. Hemin-requiring Haemophilus species have a hemin-sparing compensatory mechanism that allows growth under conditions under which hemin-independent Haemophilus species will not grow.

THE EFFECT OF CHONDROMUCOPROTEIN ON THE SOLUBILITY AND PEROXIDATIC PROPERTIES OF HAEMOGLOBIN AND METHAEMALBUMIN IN AQUEOUS SOLUTION AND BLOOD

1. Insoluble complexes, formed by electrostatic interaction between chondromucoprotein and chromoproteins (haemoglobin, methaemalbumin), were studied by measurement of precipitated pigment and by decrease in peroxidatic activity, maximum formation from aqueous solution occurring at pH 4.0-4.6. 2. Chondromucoprotein did not form complexes with plasma haptoglobins and haptohaemoglobins under these conditions, and high concentrations had no significant effect on colorimetric estimates of serum haptoglobin, although the peroxidatic activity of haemoglobinaemic serum was depressed owing to formation of chondromucoprotein-methaemalbumin complex. 3. The complexes formed by interaction between chondromucoprotein and plasma proteins contain two protein-bound biologically active components (plasminogen, haematin), as a result of co-precipitation after interaction between their carriers and chondromucoprotein. The possible presence of other biologically active trace components is discussed. 4. The results are related to complex-formation between other plasma proteins and chondromucoprotein, and possible implications arising from the complex-forming properties of tissue and urine chondromucoprotein are referred to. It is concluded that the inability of chondromucoprotein to form complexes with normal urine proteins is due to a deficiency of fibrinogen, beta-lipoproteins and chromoproteins, which, in plasma, form a large proportion of the proteins involved in complex-formation.

HAEMOPROTEINS AND HAEM SYNTHESIS IN FACULTATIVE PHOTOSYNTHETIC AND DENITRIFYING BACTERIA

1. A simple spectrophotometric method is described for the measurement of various haemoproteins in extracts of photosynthetic and non-photosynthetic bacteria. The method is based on measurements of difference spectra at the Soret maxima. 2. In photosynthetic bacteria of the Athiorhodaceae group the concentration of carbon monoxide-binding haemoprotein and of cytochromes of the b and c types is two to three times as high in anaerobically grown cells as in those grown aerobically. 3. During the adaptation of Rhodopseudomonas spheroides 8253 to form photosynthetic pigments the concentration of each of these haemoproteins increases in parallel with that of the bacteriochlorophyll. 4. The carbon monoxide-binding haemoprotein in aerobically grown Rps. spheroides 8253, in contrast with anaerobically grown cells, is predominantly in the particulate fraction of extracts prepared by ultrasonic vibration. The b- and c-type cytochromes are approximately equally distributed between each fraction in extracts from both types of cell. 5. Extracts of Micrococcus denitrificans grown anaerobically on nitrate contain more cytochromes of the b and c types, as well as of the carbon monoxide-binding pigment, than do those from aerobically grown cells. 6. The activity of ferrochelatase in both Rps. spheroides 8253 and M. denitrificans was similar in extracts from cells grown aerobically and anaerobically, though the haemoprotein content was higher under the latter conditions. Coproporphyrinogen oxidative decarboxylase could not be demonstrated in cell-free extracts of either organism.

EFFECT OF ANAEROBIC GROWTH ON NITRATE REDUCTION BY STAPHYLOCOCCUS EPIDERMIDIS

Jacobs, N. J. (American Meat Institute Foundation, Chicago, Ill.), J. Johantges, and R. H. Deibel. Effect of anaerobic growth on nitrate reduction by Staphylococcus epidermidis. J. Bacteriol. 85:782-787. 1963.-In anaerobic cultures, a strain of Staphylococcus epidermidis failed to reduce nitrate, although nitrate was reduced in stationary cultures grown in the presence of air. Resting suspensions of cells grown in air reduced nitrate. Although suspensions of cells grown anaerobically did not reduce nitrate, the nitrate reductase enzyme was shown to be present. When the artificial electron carrier, benzyl viologen, was added to suspensions of cells grown anaerobically, nitrate was reduced, indicating that an electron carrier required for nitrate reduction was missing. The addition of hemin to the growth medium enabled anaerobic cultures to reduce nitrate.

CATALASE ACTIVITY OF TWO STREPTOCOCCUS FAECALIS STRAINS AND ITS ENHANCEMENT BY AEROBIOSIS AND ADDED CATIONS

Jones, Dorothy (American Meat Institute Foundation, Chicago, Ill.), R. H. Deibel, and C. F. Niven, Jr. Catalase activity of two Streptococcus faecalis strains and its enhancement by aerobiosis and added cations. J. Bacteriol. 88:602-610. 1964.-The nature of catalase activity noted in two unusual Streptococcus faecalis strains was determined. Enzyme activity was lost slowly when cultures were maintained by daily transfer in test tubes of broth media. Loss of activity could be prevented by aerobic culture. Supplementation of the growth medium with ferric, manganese, and zinc ions, as well as aerobiosis, enhanced catalase activity. However, addition of these cations to cell suspensions or to cell-free extracts did not increase catalase activity. Although oxygen was observed to be one of the reaction end products, the catalase activity was not inhibited by cyanide or azide, and the iron-porphyrin coenzyme of classical catalase was not detected. The enzyme was purified 185-fold by precipitation with ammonium sulfate, followed by chromotography on a diethylaminoethyl cellulose column.

FLAVINE ADENINE DINUCLEOTIDE-LINKED MALIC DEHYDROGENASE FROM ACETOBACTER XYLINUM

Benziman, Moshe (The Hebrew University of Jerusalem, Jerusalem, Israel), and Y. Galanter. Flavine adenine dinucleotide-linked malic dehydrogenase from Acetobacter xylinum. J. Bacteriol. 88:1010-1018. 1964.-The properties of the pyridine nucleotide-nonlinked malic dehydrogenase of Acetobacter xylinum were investigated in the supernatant fluid obtained by high-speed centrifugation of sonic extracts. Ferricyanide, phenazine methosulfate, and to a lesser extent dichlorophenolindophenol were active as oxidants for malate oxidation. After acid ammonium sulfate precipitation, the enzyme lost its malate-oxidizing activity. The enzyme was reactivated by low concentrations of flavine adenine dinucleotide (FAD) but not by flavine mononucleotide (FMN) or riboflavine. Atabrine inhibited the enzyme, and the inhibition was relieved by FAD but not by FMN or riboflavine. Malate-oxidizing activity was inhibited by hematin. The inhibition was prevented by imidazole or globin. o-Phenanthroline, 8-hydroxy quinoline, alpha,alpha'-dipyridyl, and p-chloromercuribenzoate inhibited malate oxidation. Amytal markedly inhibited oxidation of malate in the presence of oxygen, phenazine methosulfate, or dichlorophenolindophenol, but not in the presence of ferricyanide. The results suggest that the malic dehydrogenase of A. xylinum is a FAD enzyme, which contains an ironbinding site essential for its activity. Nonheme iron and sulfhydro groups are possibly involved in enzyme activity. The malic dehydrogenase is functionally linked to the cytochrome chain.

HAEM SYNTHASE AND COBALT PORPHYRIN SYNTHASE IN VARIOUS MICRO-ORGANISMS

1. The preparation of a crude extract of Clostridium tetanomorphum containing cobalt porphyrin synthase but little haem-synthase activity is described. 2. The properties of cobalt porphyrin synthase in the clostridial extracts is compared with the properties of a haem synthase present in crude extracts of the yeast Torulopsis utilis. 3. Cobalt porphyrin synthase in extracts of C. tetanomorphum inserts Co(2+) ions into the following dicarboxylic porphyrins in descending order of rate of insertion: meso-, deutero- and proto-porphyrins. Esterification renders meso- and deutero-porphyrins inactive as substrates. Neither the tetracarboxylic (coproporphyrin III) nor the octacarboxylic (uroporphyrin III) compounds are converted into cobalt porphyrins by the extract, but the non-enzymic incorporation of Co(2+) ions into these two porphyrins is rapid. These extracts are unable to insert Mn(2+), Zn(2+), Mg(2+) or Cu(2+) ions into mesoporphyrin. 4. Crude extracts of T. utilis readily insert both Co(2+) and Fe(2+) ions into deutero-, meso, and proto-porphyrins. Unlike the extracts of C. tetanomorphum, these preparations catalyse the insertion of Co(2+) ions into deuteroporphyrin more rapidly than into mesoporphyrin. This parallels the formation of haems by the T. utilis extract. 5. Cobalt porphyrin synthase is present in the particulate fraction of the extracts of C. tetanomorphum but requires a heat-stable factor present in the soluble fraction. This soluble factor can be replaced by GSH. 6. Cobalt porphyrin synthase in the clostridial extract is inhibited by iodoacetamide and to a smaller extent by p-chloromercuribenzoate and N-ethylmaleimide. The haem synthases of T. utilis and Micrococcus denitrificans are also inhibited by various thiol reagents.

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.

EFFECT OF HEMIN AND OXYGEN TENSION ON GROWTH AND NITRATE REDUCTION BY BACTERIA

Jacobs, N. J. (American Meat Institute Foundation, Chicago, Ill.), R. E. Heady, J. M. Jacobs, K. Chan, and R. H. Deibel. Effect of hemin and oxygen tension on growth and nitrate reduction by bacteria. J. Bacteriol. 87:1406-1411. 1964.-The effect of hemin supplementation of growth media on the ability of several bacteria to reduce nitrate was studied. Added hemin had no detectable effect on the ability of these organisms to reduce nitrate when grown in stationary cultures exposed to air. However, under anaerobic conditions, six strains of facultatively anaerobic staphylococci required hemin for nitrate reduction and growth stimulation in complex, nitrate-containing media. In a nutritionally defined medium, one strain of Staphylococcus required both hemin and nitrate for anaerobic growth. Anaerobic growth and nitrite production of the aerobe Bacillus subtilis was stimulated by addition of hemin. However, the anaerobic growth response was markedly de-decreased as compared with that obtained under static atmospheric conditions. Hemin had no detectable effect on anaerobic nitrate reduction or growth of the obligate aerobe Pseudomonas denitrificans, or of the facultative anaerobes Escherichia coli, B. polymyxa, and Corynebacterium diphtheriae.

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.