DNA polymorphisms in the ψβ1- and β-globin gene regions in asian macaques

DNA polymorphisms in the ₁--globin gene region in nine Asian macaques(Macaca fuscata, M. mulatta, M. nemestrina, M. cyclopis, M. fascicularis, M. arctoides, M. radiata, M. maura, andM. assamensis) were examined using several restriction endonucleases and the human ₁, IVS2, and IVS2 probes. TheBamHI site 3 to the -globin gene was polymorphic inM. fuscata andM. mulatta, while the HincII site and the EcoRI site in the ₁-globin gene region was highly polymorphic inM. fuscata andM. mulatta, respectively. These polymorphic sites also seem to be present in other Asian macaques. The present study of the polymorphism at theBamHI site 3 to the -globin gene in Asian macaques supports, at the nuclear DNA level, the idea that thefascicularis group includingM. fuscata, M. mulatta, M. cyclopis, andM. fascicularis is different from other Asian macaque groups.This study was supported in part by the Cooperation Research Program of the Primate Research Institute, Kyoto University.     

The mitochondrial membrane potential (deltapsi(m)) in apoptosis; an update

Mitochondrial dysfunction has been shown to participate in the induction of apoptosis and has even been suggested to be central to the apoptotic pathway. Indeed, opening of the mitochondrial permeability transition pore has been demonstrated to induce depolarization of the transmembrane potential (_m), release of apoptogenic factors and loss of oxidative phosphorylation. In some apoptotic systems, loss of _m may be an early event in the apoptotic process. However, there are emerging data suggesting that, depending on the model of apoptosis, the loss of _m may not be an early requirement for apoptosis, but on the contrary may be a consequence of the apoptotic-signaling pathway. Furthermore, to add to these conflicting data, loss of _m has been demonstrated to not be required for cytochrome c release, whereas release of apoptosis inducing factor AIF is dependent upon disruption of _m early in the apoptotic pathway. Together, the existing literature suggests that depending on the cell system under investigation and the apoptotic stimuli used, dissipation of _m may or may not be an early event in the apoptotic pathway. Discrepancies in this area of apoptosis research may be attributed to the fluorochromes used to detect _m. Differential degrees of sensitivity of these fluorochromes exist, and there are also important factors that contribute to their ability to accurately discriminate changes in _m.     

Endothelin-1 and insulin induce cellular inactivation of protein kinase FA/glycogen synthase kinase-3α in a common signaling pathway

In this study, we investigate the effects of endothelin-1 (ET-1) and insulin on the cellular activity of protein kinase F_A/glycogen synthase kinase-3 (kinase F_A/GSK-3) in rat adipocytes. The cellular activity of kinase F_A/GSK-3 is inhibited to 50% of control within 30 min when cells are treated with 1 nM ET-1 at 37°C; in addition, significant inhibition to 60% of control is observed at as low as 1 pM ET-1. Conversely, ET-1 at concentrations up to 1 nM has no direct effect on purified kinase F_A/GSK-3 in vitro. Immunoblotting analysis further reveals that the protein level of this kinase is not significantly changed when treated with 1 nM ET-1 for 30 min. Similar to ET-1, insulin as low as 10 nM can also induce inactivation of kinase F_A/GSK-3 to 50% of control in adipocytes when processed under identical conditions. Most importantly, when treated with both insulin and ET-1, the activity of kinase F_A/GSK-3 can be decreased only to 50% of control. Taken together, the results provide initial evidence that ET-1 and insulin may regulate this important multisubstrate/multifunctional protein kinase in a common signaling pathway in cells.     

Evidence of β-carotene 7,8(7′,8′) oxygenase (β-cyclocitral,crocetindial generating) in Microcystis

A -carotene oxygenase is described which occurs in the Cyanobacterium Microcystis. It cleaves -carotene and zeaxanthin specifically at the positions 7,8 and 7,8, while echinenone and myxoxanthophyll are not affected. The oxidative cleavage of -carotene leads to the formation of -cyclocitral and crocetindial and that of zeaxanthin to hydroxy--cyclocitral and crocetindial in nearly stoichiometric amounts. Oxidant is dioxygen as has been demonstrated by high incroporation (86%) of ¹⁸O₂ into -cyclocitral. -Carotene oxygenase is membrane bound, sensitive to sulfhydryl reagents, antioxidants and chelating agents. Iron seems to be an essential part of the enzyme activity. Cofactors necessary for the reaction could not be detected.Abbreviations TLC thin layer-chromatography - PIPES piperazine-N,N-bis-(2-ethanesulfonate) Na - TES 2{[tris-(hydroxymethyl)-methyl]-amino} ethanesulfonic acid Dedicated to Professor G. Drews on occasion of his 60th birthday     

Existence and uniqueness of a sharp travelling wave in degenerate non-linear diffusion Fisher-KPP equations

In this paper we use a dynamical systems approach to prove the existence of a unique critical value c ^* of the speed c for which the degenerate density-dependent diffusion equation u _ct = [D(u)u _x ] _x + g(u) has: 1. no travelling wave solutions for 0 < c < c ^*, 2. a travelling wave solution u(x, t) = (x - c ^* t) of sharp type satisfying (– ) = 1, () = 0 ^*; '(^*–) = – c ^*/D'(0), '(^*+) = 0 and 3. a continuum of travelling wave solutions of monotone decreasing front type for each c > c ^*. These fronts satisfy the boundary conditions (– ) = 1, '(– ) = (+ ) = '(+ ) = 0. We illustrate our analytical results with some numerical solutions.     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

Identification of beta subunit of the rhesus monkey chorionic gonadotropin (rmCG)

Chorionic gonadotropin (CG) is a placental derived hormone that plays a crucial role in successful implantation and establishment of early pregnancy in the primates. The rhesus monkey was chosen as a model to understand the feasibility of developing human DNA immuno-contraceptive. The coding region of rhesus monkey CG -subunit (rmCG) was isolated by the TDRT-PCR method. The nucleotide sequence including the leader peptide was 499 nucleotide long and encoded 166 amino acids. In comparing with the previous known primates CG -subunits, the rmCG was the highest degree of homology with baboon CG -subunit at the deduced amino acid sequence (94%), 79.5% homology with human CG -subunit and 70.4% homology with marmoset monkey CG -subunit. The eukaryotic expression vector pCMV4-rmCG inserted full-coding cDNA sequence of rmCG was constructed, and the expression of rmCG -subunit in HeLa cells transient expressing system in vitro and BALB/c mice in vivo was determined. The results demonstrated that the recombinant PCMV4-rmCG eukaryotic expression vector could express rmCG -subunit in vitro and in vivo.     

Purification and characterization of aspartate aminotransferase from developing embryos of the camel tick Hyalomma dromedarii

Aspartate transaminase (AST) activity in the camel tick Hyalomma dromedarii was followed throughout embryogenesis. During purification of AST to homogeneity, ion exchange chromatography lead to four separate forms (termed I, II, III and IV). AST II with the highest specific activity was pure after chromatography on Sephacryl S-300. The molecular mass of AST II was 52KDa for the native enzyme, composed of one subunit of 50KDa. AST II had a Km value of 0.67mM for -ketoglutarate and 15.1mM for aspartate. AST II had a pH optimum of 7.5 with heat stability up to 50°C for 15min. The enzyme was activated by MnCl₂, and inhibited by CaCl₂, MgCl₂, NiCl₂, and ZnCl₂.     

Immunocytochemical evidence for intragranular processing of pro-opiomelanocortin in the melanotropic cells of the rabbit

Summary The immunogold technique, employing antisera with clear-cut specificities, was used to localise different processing stages of pro-opiomelanocortin (POMC) in rabbit melanotropic cells. While the antiserum against ₃-MSH labelled all the secretory granules including intrasaccular condensations in the Golgi apparatus, antisera against -MSH only labelled extra-Golgi secretory vesicles (SV). All extra-Golgi SV were likewise labelled with the three antisera against -MSH used, despite their different specificities for the desacetylated, N-acetylated or C-amidated forms of the peptide. The antibody against -endorphin also labelled the extra-Golgi SV, while only some SV were labelled with the antibody against -endorphin. These results correlate with biochemical data in favour of mainly — if not exclusively — intragranular processing of POMC. Except for ₃-MSH, the cleavage of which could coincide with Golgi packaging of secretory material, other post-translational modifications of the precursor seem to occur when SV are discharged outside the Golgi area. The cleavage of -endorphin appears to be a later step in POMC processing, occurring in some mature SV.     

A mathematical model of the interactions in the mixed culture of invertebrates and algae in the “producer–consumer” aquatic biotic cycle

This paper presents a mathematical model of interactions between two herbivorous invertebrates (ciliate Paramecium caudatum and rotifer Brachionus plicatilis) and two planktonic algae (Chlorella vulgaris and Scenedesmus quadricauda) spatially segregated in two compartments of a chemostat–type experimental microcosm system. The model mimics a producer–consumer aquatic biotic cycle, describing the dynamics of the mixed culture of ciliates and rotifers, as consumer compartment, feeding on the mixed algal culture, as producer compartment, under N-limiting conditions. We experimentally found that metabolites of the alga Scenedesmus produce an adverse effect on the reproduction of ciliate Paramecium. Taking this effect into account improved the behavior of the model, the results of which came into qualitative agreement with the experimental results. Both our experimental and modeling approaches demonstrated that, even in conditions of a spatially–segregated producer-consumer biotic cycle, species coexistence is impossible either in the mixed algal culture or in the mixed invertebrate culture. Scenedesmus excluded Chlorella, whereas Brachionus excluded Paramecium.     

Gibberellins play a role in the interaction between imidazole fungicides and cytokinins in Araceae

Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA₃ inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA₃, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - [9R-5P]DHZ 9--d-ribofuranosyl-dihydrozeatin-monophosphate - [9R-5P]iP 6-isopentenyl-9--d-ribofuranosyladenine-monophosphate - [9R-5P]Z 9--d-ribofuranosyl-zeatin-monophosphate - [9G]BA 6-benzyl-9--d-glucopyranosyladenine - [9G]DHZ 9--d-glucopyranosyl-dihydrozeatin - [9G]iP 6-isopentenyl-9--d-glucopyranosyladenine - [9G]Z 9--d-glucopyranosyl-zeatin - [9R]BA 6-benzyl-9--d-ribofuranosyladenine - [9R]DHZ 9--d-ribofuranosyl-dihydrozeatin - [9R]iP 6-isopentenyl-9--d-ribofuranosyladenine - [9R]Z 9--d-ribofuranosyl-zeatin - BA 6-benzyladenine - DHZ dihydrozeatin - ES⁺ LC-MS/MS HPLC coupled Electrospray Tandem Mass Spectrometry - f.m. fresh mass - mT 6-(3-hydroxybenzyl)adenine - IMA imazalil - iP isopentenyladenine - NAA 1-naphthalene acetic acid - NFT Nutrient Film Technique - (OG)[9R]DHZ O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin - (OG)[9R]Z O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin - (OG)DHZ O--d-glucopyranosyl-dihydrozeatin - (OG)Z O--d-glucopyranosyl-zeatin - PAR Photosynthetic Active Radiation - PBZ paclobutrazol - PRO prochloraz - TDZ thidiazuron - TRI triflurnizole - Z zeatin     

Requirements for in vitro propagation of seven nitrogen-fixing Alnus species

Studies on the in vitro propagation of Alnus crispa, A. glutinosa, A. incana, A. japonica, A. rubra, A. sinuata and A. viridis indicated interspecific as well as intraspecific variations in their requirements for in vitro culture. The WPM and Blaydes media supported, respectively, growth of A. glutinosa and A. crispa but not that of both species, while the MS medium induced equal or significantly better growth than WPM and Blaydes media for both species. The optimum type and concentration of sugar to be used in the multiplication medium varied with species. Only A. glutinosa showed good growth on sucrose while glucose was optimum for all other species but at different concentrations. All species rooted in 3 weeks on half-strength MS medium including 1 M IBA. All clones of A. glutinosa and A. rubra rooted 100%, whereas easy-to-root and difficult-to-root clones were observed in the other species. In the rooting medium, glucose promoted rooting of the difficult-to-root clones better than sucrose. Survival following transfer to an artificial substrate was 100% for all species. Nodulation tests using pure cultures of two Frankia strains showed 100% nodulation on all Alnus clones.     

An Analysis of the Amino Acid Clustering Pattern in (α/β)8 Barrel Proteins

The (/)₈ barrel proteins, in spite of having a common fold, do not show any sequence similarity. In order to understand the factors which are responsible for maintaining the common fold, the three-dimensional structures of 36 (/)₈ barrel proteins are analyzed for the presence of identical amino acid clusters or physicochemically similar clusters. The results reveal 14 identical amino acid clusters and a large number of physicochemically similar clusters. Further analysis of the similar clusters points to the conservation of secondary structures, the presence of pairs of residues occupying topologically equivalent secondary structures, and the presence of certain key residues which may play a vital role in directing and stabilizing the (/)₈ barrel fold.     

A mathematical theory of the functional dynamics of cortical and thalamic nervous tissue

It is proposed that distinct anatomical regions of cerebral cortex and of thalamic nuclei are functionally two-dimensional. On this view, the third (radial) dimension of cortical and thalamic structures is associated with a redundancy of circuits and functions so that reliable signal processing obtains in the presence of noisy or ambiguous stimuli.A mathematical model of simple cortical and thalamic nervous tissue is consequently developed, comprising two types of neurons (excitatory and inhibitory), homogeneously distributed in planar sheets, and interacting by way of recurrent lateral connexions. Following a discussion of certain anatomical and physiological restrictions on such interactions, numerical solutions of the relevant non-linear integro-differential equations are obtained. The results fall conveniently into three categories, each of which is postulated to correspond to a distinct type of tissue: sensory neo-cortex, archior prefrontal cortex, and thalamus.The different categories of solution are referred to as dynamical modes. The mode appropriate to thalamus involves a variety of non-linear oscillatory phenomena. That appropriate to archior prefrontal cortex is defined by the existence of spatially inhomogeneous stable steady states which retain contour information about prior stimuli. Finally, the mode appropriate to sensory neo-cortex involves active transient responses. It is shown that this particular mode reproduces some of the phenomenology of visual psychophysics, including spatial modulation transfer function determinations, certain metacontrast effects, and the spatial hysteresis phenomenon found in stereopsis.List of Symbols (t) Post-synaptic membrane potential (psp) - Maximum amplitude of psp - t Time - The neuronal membrane time constant - Threshold value of membrane potential - r Absolute refractory period - Synaptic operating delay - v Velocity of propagation of action potentil - x Cartesian coordinate - _jj (x) The probability that cells of class j are connected with cells of class j a distance x away - b _jj The mean synaptic weight of synapses of the jj-th class at x - _jj The space constant for connectivity - _e Surface density of excitatory neurons in a one-dimensional homogeneous and isotropic tissue - _i Surface density of inhibitory neurons in a one-dimensional homogeneous and isotropic tissue - E(x, t) Excitatory Activity, proportion of excitatory cells becoming active per unit time at the instant t, at the point x - I(x, t) Inhibitory Activity, proportion of inhibitory cells becoming active per unit time at the instant t, at the point x - x A small segment of tissue - t A small interval of time - P(x, t) Afferent excitation or inhibition to excitatory neurons - Q(x, t) Afferent excitation or inhibition to inhibitory neurons - N _e (x, t) Mean integrated excitation generated within excitatory neurons at x - N _i (x, t) Mean integrated excitation generated within inhibitory neurons at x - _e [N _e ] Expected proportion of excitatory neurons receiving at least threshold excitation per unit time, as a function of N _e - _i [N _i ] Expected proportion of inhibitory neurons receiving at least threshold excitation per unit time, as a function of N _i - G( _e ) Distribution function of excitatory neuronal thresholds - G( ₁ ) Distribution function of inhibitory neuronal thresholds - ₁ A fixed value of neuronal threshold - h(N _e ; ₁) Proportion per unit time of excitatory neurons at x reaching ₁ with a mean excitation N _e - 1[ ] Heaviside's step-function - R _e (x, t) Number of excitatory neurons which are sensitive at the instant t - R _i (x, t) Number of inhibitory neurons which are sensitive at the instant t - R _e Refractory period of excitatory neurons - r _i Refractory period of inhibitory neurons - E(x, t) Time coarse-grained excitatory activity - I(x, t) Time coarse-grained inhibitory activity - Spatial convolution - Threshold of a neuronal aggregate - v Sensitivity coefficient of response of a neuronal aggregate - E(t) Time coarse-grained spatially localised excitatory activity - I(t)> Time coarse-grained spatially localised inhibitory activity - L ₁,L ₂,L,Q See § 2.2.1, § 2.2.7, § 3.1 - Velocity with which retinal images are moved apart - Stimulus width - E _o, I _o Spatially homogeneous steady states of neuronal activity - k _e ,k _ij S _e S _ij See § 5.1     

Effect of minerals on the production of the delta endotoxin byBacillus thuringiensis subsp.israelensis

Summary A study has been made of the mineral requirements ofBacillus thuringiensis subsp.israelensis for production of the mosquitocide delta endotoxin. The optimum concentrations of K₂HOP₄, MgSO₄.7H₂O and CaCO₃ for toxin production are 1g/l, 0.3g/l and 1g/l respectively while the elements Fe, Mn, Cu are required at levels of 2 g/ml, 5 g/ml and 0.25 g/ml respectively.     

Photoreversion und Photoprotektion bei UV-induzierten Mutationen des nichtphotoreaktivierbaren Bacteriums E.coli phr?

Summary Stationary phase cells of strain phr^–/MC 2 ofE. coli are not photoreactivable but the frequency of UV-induced mutations to low Streptomycine-resistance (S 3, 3/ml) is decreased strongly by illumination with light of fluorescence tubes (310 to 500 nm) after UV-irradiation. Also dark-reversion (DRM) of these mutations due to keeping UV-irradiated cells in saline is observed. Illumination before UV-irradiation decreases the frequency of the mutations (photoprotection against mutation=PPM) to the same extent as the combined action of photoreversion (PRM) and DRM. The lag-phase of cell division is prolonged strongly by illumination from 80 min without light to 150 min by the light-dose of highest activity. The additional lag is nearly the same if the illumination is done before, after or without UV-irradiation; this lag is about additive to the small lag caused by UV. Pre-illumination of the stationary-phase cells does not cause photoprotection against killing (PP), it even decreases the survival after high UV-doses. The observations support the hypothesis that PRM in this strain may be indirect, i.e. caused by the light-induced additional division lag which enhances the dark repair of UV-premutations. Also spontaneous premutations which are apparently present in the stationary-phase cells seem to be influenced by the light in this way.     

Observations on naturally and artificially diseased tropical corals: A scanning electron microscope study

Scanning electron microscopic (SEM) observations of naturally and artificially diseased corals reveal that the disease is characterized by a filamentous matrix of cyanobacterial andBeggiatoa filaments. Spiral bacteria are commonly embedded in the matrix. The artificial disease is not manifested as the characteristic black line disease and does not contain filaments of cyanobacteria. This suggests that cyanobacteria are necessary for the black line phenomenon. The colorless, sulfide-oxidizing bacteriumBeggiatoa, however, is always associated with the disease.     

Enzymic activities and galactomannan mobilisation in germinating seeds of fenugreek (Trigonella fœnum-graecum L. Leguminosae)

Summary The activities of -galactosidase, -mannosidase and -mannosidase were determined in extracts from the endosperm and from the embryo of fenugreek seeds at different stages of germination. Endosperm homogenates contained little or no activity of the above enzymes in the early stages of germination, before the reserve galactomannan began to be mobilised. The onset of galactomannan breakdown coincided with the appearance of -galactosidase and -mannosidase activities, which increased throughout the period of galactomannan degradation and then remained constant. A similar rise in -galactosidase and -mannosidase activities occurred during galactomannan breakdown in dry-isolated endosperms incubated under germination conditions. The increase could be suppressed by metabolic inhibitors which also inhibit galactomannan breakdown. Embryo homogenates contained high -galactosidase, high -mannosidase and some -mannosidase activity at all stages of germination.No oligomannosyl -1,4 phosphorylase activity could be detected either in the endosperm or in the embryo.It is concluded that the galactomannan of fenugreek is broken down by a series of hydrolases secreted by the aleurone layer of the endosperm. They include -galactosidase, -mannosidase and probably also endo--mannanase.This is part four in a series of papers dealing with galactomannan metabolism. Part three: Planta (Berl.) 106, 44–60 (1972).     

Biosynthesis of a blood group H1 antigen by α1,2-fucosyltransferase in PC12 cells

We have examined the expression of GDP-fucose: glycosphingolipid fucosyltransferase activity in PC12 cells and PC12 sublines in relation to the neuronal differentiation induced by nerve growth factor (NGF) or dexamethasone. Transfer of fucose to paragloboside (nLc₄Cer) yielded a product which was determined to be a blood group H₁ antigen (Fuc1-2Gal1-4GlcNAc1-3Gal1-4Glc-Cer) by gas chromatography/mass spectrometry analysis and enzymatic hydrolysis, suggesting that PC12 cells have an 1,2-fucosyltransferase. Lactosylceramide was also fucosylated at a reduced rate. When the differentiation of PC12 cells and PC12 subline cells, PC12D and MR31, was induced by exposure to either NGF or dexamethasone, the fucosyltransferase activity for nLc₄Cer was found to decrease in both cell lines, suggesting the association with cell differentiation. This is the first report of the presence of an 1,2-fucosyltransferase in cultured neuronal cell lines which catalyses thein vitro biosynthesis from nLc₄Cer of a type-2 chain glycosphingolipid having the blood group H₁ determinant. The disaccharides, -lactose andN-acetyllactosamine, were also fucosylated by PC12 cell enzyme, although the specificity for the carbohydrate structure was different from that for glycosphingolipids.Abbreviations Glc d-glucose - Gal d-galactose - GlcNAc N-acetyl-d-glucosamine - Fuc l-fucose - Cer ceramide - nLc₄Cer neolactotetraosylceramide (paragloboside) - GDP guanosine diphosphate - CDP cytidine diphosphate - CTP cytidine triphosphate - NGF nerve growth factor - DX dexamethasone - GC/MS gas chromatography/mass spectrometry     

Electron transport and respiration in Beggiatoa and Vitreoscilla

Seven strains of bacteria belonging to the Beggiatoa-Vitreoscilla group were studied for their respiratory activity and for the presence of electron transport conponents. All strains tested oxidized [1-¹⁴C] and [2-¹⁴C] acetate to ¹⁴CO₂ at relatively high rates. All strains tested were N,N,N,N-tetramethylphenylenediamine (TMPD)-oxidase positive and contained spectra representing a-type and carbon monoxide-binding cytochromes. Most of the strains also contained spectra representing c-type and b-type cytochromes. Beggiatoa alba B18LD contained b-type, a-type, c-type and CO-binding cytochromes, the latter two being located in the 144,000 x g soluble fraction. B. alba also contained ubiquinone-8 as its only detectable quinone.Non-standard abbreviations BSS basal salts solution - BH Beggiatoa heterotrophic medium - BSO Beggiatoa sulfide oxidation medium - TMPD N,N,N,N-tetramethylphenylenediamine - Q8 ubiquinone-8