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.

Deoxyribonucleic acid homology among the fruiting myxobacteria

Deoxyribonucleic acid similarities were determined by competition experiments. The several strains of fruiting myxobacteria tested showed from 23 to 89% homology with the reference strains Myxococcus xanthus (FB) and M. fulvus (M6).

Deoxyribonucleic acid homology in bacterial taxonomy: effect of incubation temperature on reaction specificity

Parameters affecting deoxyribonucleic acid duplex (DNA-DNA) formation on membrane filters were evaluated. The reference strains used were Cytophaga succinicans strain 8, which has a guanine plus cytosine (GC) content of 38%, and Myxococcus xanthus strain FB, which has a GC content of 70%. Both organisms are gliding bacteria classified among the myxobacteria. Among the parameters evaluated, the incubation temperature used during duplex formation was found to be the most important in terms of the physical nature of the reaction product. When an incubation temperature 25 C below the melting point (T(m)) of the native DNA was used, homologous duplexes exhibited a thermal stability similar to that of native DNA. At 35 C below the T(m), a considerable proportion of the duplexes were of much lower stability; at 40 C below the T(m), most of the duplexes were of much lower stability. Similar duplexes of low stability were also formed between DNA molecules from morphologically and nutritionally diverse organisms, provided the GC percentages of the DNA preparations were similar. Competition between unlabeled and labeled DNA fragments for binding sites on immobilized DNA was also greatly influenced by the incubation temperature. Heterologous DNA-DNA complexes exhibited thermal stabilities which correlated with measurements of DNA homology in experiments involving competition. In addition, the difference in thermal stabilities of heterologous and homologous DNA complexes (DeltaT'(m)) may provide a measure of divergence in nucleotide sequences.

The fine structure of Chondrococcus columnaris. II. Structure and formation of rhapidosomes

When cells of C. columnaris were broken open, treated with PTA, and examined in the electron microscope, tubular structures (rhapidosomes) were present in the preparations. The rhapidosomes are approximately 300 A in diameter. Their length varies from about 500 to about 15,000 A. An axial hole which runs the length of the rhapidosomes appears to widen and narrow with a regular periodicity. End-on views of short segments of rhapidosomes revealed the presence of subunits around their outside peripheries. The results of studies of lysed cells and of sectioned cells indicate that the rhapidosomes are produced during the disintegration of cells. It seems likely that the compound membranes of the mesosomes break down to give rise to the tubular structures. The mesosomal origin of rhapidosomes is postulated only for the rhapidosomes of C. columnaris, since the origin of rhapidosomes from other organisms was not investigated during this study. The rhapidosomes of C. columnaris may be unrelated to those of S. grandis, S. myxococcoides, A. violaceum, and Sorangium 495, since there was a difference in the details of fine structure between rhapidosomes from C. columnaris and those found in the other four organisms.

Galactosamine glycan of Chondrococcus columnaris

The marked viscosity of liquid cultures of the myxobacterium Chon-rococcus columnaris is caused by production of an extracellular polysaccharide. The polysaccharide is a high-molecular-weight homopolymer of D-galactosamine in which the galactosamine subunits are connected by (alpha)-(l-->4) glycosidic linkages. Half of the amino groups are acetylated.