Bacteriocin production by strains of Bacteroides isolated from human feces and the role of these strains in the bacterial ecology of the colon

Several human fecal isolates of Bacteroides have been found to produce bacteriocins. The bacteriocin-producing strain T1-1 was studied in the most detail. Strain T1-1 belongs to the 0061-1 deoxyribonucleic acid (DNA) homology group of Bacteroides. This homology group phenotypically resembles Bacteroides thetaiotaomicron but has little DNA homology with it. The bacteriocin-producing strains T1-12 and T1-48 belong to the 3452-A DNA homology group. This group has DNA homology with B. thetaiotaomicron and Bacteroides ovatus. The bacteriocin-producing strain T1-42 remains unidentified in that it does not belong to any recognized DNA homology group of the saccharolytic intestinal bacteroides. The extracellular bacteriocin produced by strain T1-1 was specifically bactericidal for other bacteria within the genus Bacteroides. The highest bacteriocin titers (32 to 64) were produced in complex media, with only trace amounts being produced in a defined medium. The bacteriocin appeared to have a high molecular weight (>/=300,000) and was unusual because it was stable from pH 1 to 12 and only a 50% reduction in activity resulted after 15 min at 121 degrees C in an autoclave. It was inactivated by trypsin and Pronase. Strain T1-1 was isolated from all three fecal samples obtained over a 25-week period from an individual who was part of a National Aeronautics and Space Administration mock Skylab flight. Strains T1-12, T1-48, and T1-42 were isolated only from the first fecal sample. Each of these strains was immune to the bacteriocins produced by the others. These strains were found to coexist in the colon with a larger population of non-bacteriocin-producing, bacteriocin-susceptible strains of Bacteroides.

Tryptic cleavage of rat liver sulfite oxidase. Isolation and characterization of molybdenum and heme domains

Treatment of rat liver sulfite oxidase with trypsin leads to loss of ability to oxidize sulfite in the presence of cytochrome c as electron acceptor. Ability to oxidize sulfite with ferricyanide as acceptor is undiminished, while sulfite leads to O2 activity is partially retained. Gel filtration of the proteolytic products has led to the isolation of two major fragments of dissimilar size derived from sulfite oxidase. The smaller fragment has a molecular weight of 9500 and appears to be monomeric when detached from sulfite oxidase. It contains the heme in its cytochrome b5 structure, has no sulfite oxidase activity, and is reducible with dithionite but not with sulfite. The heme fragment can mediate electron transfer between pig liver microsomal NADH cytochrome b5 reductase and cytochrome c. The larger fragment has a molecular weight of 47,400 under denaturing conditions but elutes from Sephadex G-200 as a dimer. It contains no heme but retains all of the molybdenum and the modified sulfite-oxidizing capacity present in the proteolytic mixture. All of the EPR properties of the molybdenum center of native sulfite oxidase are retained in the molybdenum fragment. The molybdenum center is a weak chromophore with an absorption sectrum suggestive of coordination with sulfur ligands. Reduction by sulfite generates a spectrum attributable to molybdenum (V). Spectra of oxidized and sulfite-reduced preparations are sensitive to anions and pH. NH2-terminal analysis of native sulfite oxidase and the two tryptic fragments has permitted the conclusion that the sequence represented by the heme fragment is the NH2 terminus of native enzyme. These studies have demonstrated that the two cofactor moieties of sulfite oxidase are contained in distinct domains which are covalently held in contiguity by means of an exposed hinge region. Isolation of functional heme and molybdenum domains of sulfite oxidase after tryptic cleavage has demonstrated conclusively that the cytochrome b5 region of the molecule is required for electron transfer to the physiological acceptor, cytochrome c.

Electron paramagnetic resonance of the tungsten derivative of rat liver sulfite oxidase

Sulfite oxidase purified from livers of tungsten-treated rats has been used for EPR studies of tungsten substituted at the molybdenum site of the enzyme in a fraction of the molecules. The EPR signal of W(V) in sulfite oxidase is quite similar to that of Mo(V) in its line shape and in its sensitivity to the presence of anions such as phosphate and fluoride. Hyperfine interaction with a dissociable proton is also observed in both signals. The pH-dependent alteration in line shape exhibited by the Mo(V) EPR signal of the rat liver enzyme. Incomplete reduction of the tungsten center at pH 9 is indicated by attenuated signal intensity at this pH. The W(V) signal has g values lower than those of the Mo(V) signal, has a much broader resonance envelope, and is much less readily saturated by increasing microwave power. Kinetic studies on the reduction of the heme and tungsten centers of sulfite oxidase have shown that reduction of de-molybdo forms of sulfite oxidase by sulfite is catalyzed by the residual traces of native molybdenum-containing molecules. Reduction is accomplished by electron transfer involving intermolecular heme-heme interaction. The W(V) signal is generated only after all the heme centers are reduced. The rate and extent of heme reduction at pH 9 are the same as at pH 7. Studies on the reoxidation of W(V) and reduced heme by O2 and by cytochrome c suggest that the cytochrome b5 of sulfite oxidase is the site of electron transfer to cytochrome c, whereas oxidase activity is the property of the molybdenum center. It appears that the tungsten center in sulfite oxidase is incapable of oxidizing sulfite.

Perfusion therapy for extremity melanoma

Because of their initial appearance on extremities, malignant melanomas lend themselves to isolated chemotherapeutic perfusions. Perfusion is attractive because one can deliver effective cytotoxic drugs without systemic toxicity. We are reviewing 20 patients treated between 1960 and 1973 with isolated perfusion. Melphalan (L-phenylalanine mustard) was the drug of choice. Eleven of the 20 patients had previous surgical treatment. Three of the 11 patients are still alive from 27 to 72 months postperfusion. Eight died after an average survival time of 33 months. Of the seven patients who underwent perfusion as primary therapy, four patients are alive from 25 to 76 months postperfusion, and three died after an average survival time of 34 months. There is direct correlation between stages and levels of melanoma, and perfusion and prolonged survival time.

Assessment of clinical laboratory techniques in the measurement of oxygen saturation in whole blood

The accuracy and advantages of determining percentage of hemoglobin oxygen saturation of whole blood by advanced instruments of oximetry, gas chromatography, and the computation of oxygen saturation from pO2 and pH data are compared with the Van Slyke-Neill manometric method. It was found that oximetry is extremely fast, less expensive, and more accurate than in the past, the apparatus requires little training to operate and has diminutive service maintenance. The gas chromatograph proved to be highly accurate and could serve as a standard calibration check method in place of the more time-consuming Van Slyke-Neill apparatus for oximetry and pO2 and pH electrode instrumentation. Computation of O2 saturation from pO2 and pH data also proved to be accurate, confirming that this method is more useful during cardiac surgery because it can provide additional acid-base information. In the low oxygen saturation range (less than 60%), all three methods proved to be of similar sensitivity.

Purification and properties of sulfite oxidase from human liver

Sulfite oxidase has been purified to near homogeneity from human liver. Properties of the molecule have been investigated and compared to those of the rat liver enzyme which has been isolated in a pure form. Both proteins exist as dimeric molecules with one molybdenum and one cytochrome b5-type heme per sub-unit. The human enzyme has a slightly larger subunit molecular weight (61,100 vs. 57,200 daltons) and is a more negatively charged molecule. Decreased reactivity of the human enzyme with various electron acceptors suggests the presence of nonfunctional molybdenum centers in a portion of the molecules isolated. Human liver sulfite oxidase cross-reacts strongly with antibody prepared against the rat liver enzyme. Human enzyme activity is precipitated by antibody at concentrations about twofold greater than required for comparable complexation of rat sulfite oxidase.

Human sulfite oxidase deficiency. Characterization of the molecular defect in a multicomponent system

Frozen liver tissue from an individual identified several years ago as sulfite oxidase deficient has been reexamined in light of new knowledge which has been obtained regarding the enzyme. It has been established that hepatic molybdenum levels and xanthine oxidase activity were within normal values and comparable to those observed in control samples preserved from the original study along with the deficient tissue sample. The ability of the patient's liver to synthesize the specific molybdenum cofactor required for activation of de-molybdo sulfite oxidase also appears to have been unimpaired. Using an antibody preparation directed against rat liver sulfite oxidase which also inhibits and precipitates the human enzyme, it has been determined that cross-reacting material with determinants recognized by inhibiting antibodies is absent in the liver sample from the deficient patient. Immunodiffusion experiments gave strong precipitin bands against the control liver extracts, but showed no detectable precipitin reaction between the deficient liver extract and the antibody preparation. The relationship of these findings to a second patient recently identified as sulfite oxidase deficient and to an animal model of the disease are discussed.

Inhibition of Bacteroides fragilis on blood agar plates and reversal of inhibition by added hemin

Bacteroides fragilis strains formed much smaller colonies on most types of blood agar plates than they did on the same media without blood. Blood inhibited strains of B. fragilis subsp. distasonis the most and B. fragilis subsp. fragilis the least. The inhibition could be eliminated by adding hemin to the blood agar. The inhibitory component of the blood was inside the erythrocytes and appeared to be the hemin-free globin of hemoglobin.

A comparative analysis of compartmentation of metabolism in the dorsal root ganglion and ventral spinal cord gray using [U-14C]glucose, [2-14C]glucose, [6-14C]glucose, [3,4-14C]glucose, NaH14CO3, and [2-14C]pyruvate

A detailed temporal comparison of glucose metabolism, in the production of glutamate and glutamine as well as aspartate and alamine, was conducted in order to further define the uniqueness of the dorsal root ganglion compared to the ventral spinal cord gray. Experiments with injected labeled NaHCO3 and pyruvate were used in an attempt to clarify certain aspects of the above results with different [14C]glucose precursors. The glutamine/glutamate relative specific activity ratio (RSA) was consistently lower in the ganglion than in the ventral spinal cord gray, as was also true for glutamate specific activity from the same amount of injected [14C]glucose. The ganglion is characterized by a high level of alanine production from glucose and pyruvate. The NaH14CO3 experiments suggest that CO2 fixation from [3,4-14C]-glucose in the dorsal rool ganglion resul .ts in a higher glutamine/glutamate RSA when compared to results using either [6-14C] or [2-14C]glucose.

Neuraminidase immunotherapy: serum potentiation of lymphocyte cytotoxicity related to immunoglobulin levels

Seven patients completed couses of immunotherapy using neuraminidase-altered autochthonous cells. Their response to therapy was monitored by a cytotoxicity assay using 3H-proline-tagged tumor cells from the patient's own cultured tumor in a strictly autologous system. Serum effects were measured by exposing the tumor target cells to serum to see whether this impeded (blocked) or augmented (potentiated) lymphocyte cytotoxicity. Three of the seven patients developed increasing degrees of serum blocking effect and all died within six months of completing therapy. Four of the seven showed rapidly decreasing blocking and three eventual potentiation. Three patients are living, improved, and free of evidence of tumor. There was an increase in average serum immunoglobulins in patients developing potentiation, and a decrease in those showing blocking. In any immunotherapy program attention must be given to in vitro monitoring studies, and such studies should include attention to the serum factors influencing host response.

Oxygen metabolism of catalase-negative and catalase-positive strains of Lactobacillus plantarum

Two catalase-negative strains of Lactobacillus plantarum and a strain producing the atypical, nonheme catalase were studied to determine if the ability to produce the atypical catalase conferred any growth advantage upon the producing strain. Both catalase-negative strains grew more rapidly than the catalase-positive strain under aerobic or anaerobic conditions in a glucose-containing, complex medium. Upon exhaustion of glucose from the medium, all three strains continued growth under aerobic but not under anaerobic conditions. The continued aerobic growth was accompanied by production of acetic acid in addition to the lactic acid produced during growth on glucose. Oxygen was taken up by exponential phase-cell suspensions grown on glucose when glucose or glycerol were used as substrates. Cells harvested from glucose-exhausted medium oxidized glucose, glycerol, and pyruvate. Oxygen utilization by a catalase-negative strain increased as did the specific activity of reduced nicotinamide adenine dinucleotide peroxidase during late growth in the glucose-exhausted medium. The catalase-positive strain and the catalase-negative strain tested both possessed low but readily detectable levels of superoxide dismutase throughout growth. The growth responses are discussed in terms of the presence of enzymes which would allow the cells to remove potentially damaging reduction products of O2.

Taxonomy of the Clostridia: ribosomal ribonucleic acid homologies among the species

rRNA homologies have been determined on reference strains representing 56 species of Clostridium. Competition experiments using tritium-labelled 23S rRNA were employed. The majority of the species had DNA with 27 to 28% guanine plus cytosine (%GC). These fell into rRNA homology groups I and II, which were well defined, and a third group which consisted of species which did not belong in groups I and II. Species whose DNA was 41 to 45% GC comprised a fourth group. Thirty species were placed into rRNA homology group I on the basis of having 50% or greater homology with Clostridium butyricum, C. perfringens, C. carnis, C. sporogenes, C. novyi or C. pasteurianum. Ten subgroups were delineated in homology group I. Species in each subgroup either had high homology with a particular reference species or a similar pattern of homologies to all of the reference organisms. The eleven species in rRNA homology group II had 69% or greater homology to C. lituseburense. Species in groups I and II had intergroup homologies of 20 to 40%. The six species in group II had very low homologies with groups I and II. Negligible homology also resulted when five of the species were tested against the sixth, C. ramosum. The five species having DNA with 41 to 45% GC were C. innocuum, C. sphenoides, C. indolis, C. barkeri and C. orotic um. Little rRNA homology was apparent between C. innocuum and the other high % GC species or with several Bacillus species having similar %GC DNA. Correlations between homology results and phenotypic characteristics are discussed.

Blood flow velocity in the carotid artery as a measure of myocardial contractility

An attempt was made to derive a useful noninvasive index to evalute a change in myocardial contractile state using transcutaneous Doppler flow-velocity curve from the carotid artery. In 5 mongrel dogs and in 43 patients with various heart disease, Doppler flow velocity curves were obtained from the ascending aorta intravascularly using a Doppler catheter and/or from carotid artery transcutaneously using a Doppler probe. The first derivative of left ventricular pressure (dp/dt) and electrocardiogram (ECG) were recorded simultaneously. The following 3 indices were measured from the Doppler flow-velocity curves: (1) macimum acceleration of blood flow (dv/dt), (2) time from onset of ejection to peak flow (time-to-peak), (3) time interval between the beginning of Q wave of ECG to the peak of Doppler flow velocity curve (ECG Q-Doppler peak). Among these 3 indices, only ECG Q-Doppler peak demonstrated a significant correlation between the values measured intravascularly and transcutaneously. Also, only ECG Q-Doppler peak showed significant correlation with maximum of dp/dt (max dp/dt). Since ECG Q-Doppler peak showed correlation with heart rate, the difference between observed and predicted ECG Q-Doppler peak (delta ECG Q-Doppler peak) was calculated to exclude the effect of heart rate. Predicted value of ECG Q-Doppler peak was calculated from the regression equation between heart rate and ECG Q-Doppler peak in the separate experiments. There was significant correlation between delta ECG Q-Doppler peak and max dp/dt. In 15 patients with coronary artery disease and in 16 healthy subjects, delta ECG Q-Doppler peak and the other noninvasive method (systolic time intervals) were measured. Delta ECG Q-Doppler peak showed better result in the separation of 2 groups than by systolic timeintervals. It was concluded that delta ECG Q-Doppler peak is a useful index to evaluate the myocardial contractile state since this index is readily obtained noninvasively.

Molecular basis of the biological function of molybdenum: the relationship between sulfite oxidase and the acute toxicity of bisulfite and SO2

The administration of tungsten to rats maintained on a low molybdenum diet resulted in a dose- and time-dependent loss of sulfite oxidase (EC 1.8.3.1) and xanthine oxidase (EC 1.2.3.2) activities and hepatic molybdenum. These tungsten-treated animals appeared healthy, but were more susceptible to bisulfite toxicity. The median lethal dose for intraperitoneal bisulfite was found to be 181 mg of NaHSO(3) per kg for the animals deficient in sulfite oxidase, compared to 473 mg/kg for normal rats. The survival time of rats exposed to SO(2) at concentrations of 590 ppm and higher was seen to be inversely related to the level of SO(2). At 590 ppm and 925 ppm, control animals displayed symptoms of severe respiratory toxicity before death. At 2350 ppm of SO(2), death was preceded by seizures and prostration, symptoms observed with the systemic toxicity of injected bisulfite. At 590 ppm, animals deficient in sulfite oxidase were indistinguishable from control animals. However, at 925 ppm and 2350 ppm, the deficient animals displayed symptoms of systemic toxicity and had much shorter survival times. It is concluded that sulfite oxidase is instrumental in counteracting the toxic systemic effects of bisulfite, either injected or derived from respired SO(2). Respiratory death probably results from the toxicity of gaseous SO(2) before absorption as bisulfite and cannot be alleviated by sulfite oxidase. Sulfite oxidase does not appear to be inducible by either bisulfite or SO(2).

Phthalate ester residues--their metabolism and analysis in fish

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Cell wall composition and deoxyribonucleic acid similarities among the anaerobic coryneforms, classical propionibacteria, and strains of Arachnia propionica

Eighty strains of anaerobic coryneforms were compared with 29 strains of classical propionibacteria and 8 strains of Arachnia propionica by cell wall analysis, deoxyribonucleic acid (DNA) base compositions, and nucleotide sequence similarities. The anaerobic coryneforms have DNA base compositions in the range of 58 to 64% guanine + cytosine (GC) and show at least three homology groups. The largest group corresponds to organisms identified as Propionibacterium acnes and shows about 50% homology to strains in the P. avidum homology group. The third group, P. granulosum, shows low levels of similarities to the other two. All strains of anaerobic coryneforms have some combination of galactose, glucose, or mannose as cell wall sugars, and most have alanine (ala), glutamic acid (glu), glycine (gly), and l-alpha-epsilon-diaminopimelic acid (l-DAP) as amino acids of peptidoglycan. However, a few strains in the P. acnes and P. avidum homology groups have meso-DAP and minimal amounts of glycine. Two serological types, based on cell wall antigens, were found in the P. acnes homology group. One type had galactose, glucose, and mannose as cell wall sugars, the other glucose and mannose only. The classical propionibacteria have DNA base compositions in the range of 65 to 68% GC and show four homology groups which correspond closely to van Niel's classification as given in the 7th edition of Bergey's Manual. The P. jensenii group showed about 50% homology to the P. thoenii group and about 30 to 35% to the P. acidi-propionici group. The P. freudenreichii strains showed a rather lower level of similarity (8 to 25%) to the other homology groups. Most of the strains of classical propionibacteria also have some combination of galactose, glucose, or mannose as cell wall sugars and ala, glu, gly, and l-DAP as peptidoglycan amino acids, but P. shermanii and P. freudenreichii strains, which form a single homology group, have galactose, mannose, and rhamnose as cell wall sugars and ala, glu, and meso-DAP in their peptidoglycan. There is a rather low level of DNA homology (10 to 20%) between the anaerobic coryneforms and classical propionibacteria. However, the strains of A. propionica which have a GC content of 64 to 65% and form a single homology group, show no homology to either of the other two major groups.

Partial tracheal obstruction due to anomalous origin of the left pulmonary artery

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Nucleic acid homologies among oxidase-negative Moraxella species

The deoxyribonucleic acid (DNA) base composition and DNA homologies of more than 40 strains of oxidase-negative Moraxella species were determined. These bacteria have also been identified as belonging to the Mima-Herellea-Acinetobacter group and the Bacterium anitratum group, as well as to several other genera including Achromobacter and Alcaligenes. The DNA base content of these strains ranged from 40 to 46% guanine plus cytosine. DNA-DNA competition experiments distinguished five groups whose members were determined by showing 50% or more homology to one of the reference strains: B. anitratum type B5W, Achromobacter haemolyticus var. haemolyticus, Alcaligenes haemolysans, Achromobacter metalcaligenes, and Moraxella lwoffi. A sixth group comprised those strains showing less than 50% homology to any of the reference strains. Negligible homology was found between strains of oxidase-negative and oxidase-positive Moraxella species in DNA-DNA competition experiments. However, evidence of a distant relationship between the two groups was obtained in competition experiments by using ribosomal ribonucleic acid.