Respiratory components in acidophilic bacteria that respire on iron

Abstract

Microorganisms capable of aerobic respiration on ferrous ions are spread throughout eubacterial and archaebacterial phyla. Phylogenetically distinct organisms were shown to express spectrally distinct redox‐active biomolecules during autotrophic growth on soluble iron. A new iron‐oxidizing eubacterium, designated as strain Funis, was investigated. Strain Funis was judged to be different from other known iron‐oxidizing bacteria on the bases of comparative lipid analyses, 16S rRNA sequence analyses, and cytochrome composition studies. When grown autotrophically on ferrous ions, Funis produced conspicuous levels of a novel acid‐stable, acid‐soluble yellow cytochrome with a distinctive absorbance peak at 579 nm in the reduced state.

Stopped‐flow spectrophotometric kinetic studies were conducted on respiratory chain components isolated from cell‐free extracts of Thiobacillus ferrooxidans. Experimental results were consistent with a model where the primary oxidant of ferrous ions is a highly aggregated c‐type cytochrome that then reduces the periplasmic rusticyanin. The Fe(II)‐dependent, cytochrome c‐catalyzed reduction of the rusticyanin possessed three kinetic properties in common with corresponding intact cells that respire on iron: the same anion specificity, a similar dependence of the rate on the concentration of ferrous ions, and similar rates at saturating concentrations of ferrous ions     

Fluorometric, Chromatographic, and Spectronic Evidence for the Non-indolic Nature of Citrus Auxin

Evidence for the non-indolic nature of the new citrus auxinis presented on the basis of fluorometric properties, thin-layerchromatography, Ehrlich's colour reaction, paper electrophoresis,and the infra-red spectra determinations. Citrus auxin had alower Rf in TLC than IAA, did not give the typical indole reactionwith Ehrlich's reagent, and behaved differently in electrophoresis.The infra-red spectra also provided preliminary informationconcerning chemical structure. The hypothesis that indolic compoundsconstitute the only natural auxins in higher plants should berevised in view of this evidence that a non-indole auxin existsin higher plants.     

Cell wall residues in yeast protoplast preparations

Protoplast preparations made from Saccharomyces cerevisiae by prolonged treatment with snail digestive juice contained fibrils and chitinous bud-scar residues from the original cell wall.     

Major histocompatibility (B) complex and sex effects on the phytohaemagglutinin wattle response

The influence of the major histocompatibility (B) complex and sex on the phytohaemagglutinin (PHA) wattle response was studied in 136 segregants (B2/B2, B2/B5 and B5/B5) of a fourth generation cross between inbred lines 6(1) and 15(1). At 6 weeks of age, chickens were injected with 100 micrograms purified PHA-P. Wattle thickness measurements were taken 4, 24, 48, 72 and 96 h after injection. Analysis of variance showed that 4 h after injection, males had a significantly higher response than females but the sex-genotype interaction was also significant. Females had higher responses than males 24 and 48 h after injection as a consequence of more rapid development and earlier resolution of the reaction in males. B2/B2 chickens had significantly lower responses than B5/B5 chickens 72 and 96 h after injection, signifying a faster late resolution phase in the B2/B2 genotype. The developmental and early resolution phases of the PHA wattle response were influenced by sex while the late resolution phase was influenced by B genotype.     

Allometric Root/Shoot Relationships and Predicted Water Uptake for Desert Succulents

Root morphology, shoot morphology, and water uptake for Agavedeserti and Ferocactus acanthodes of various sizes were studiedusing allometric relationships (y = ax^b) and a previously developedwater uptake model. Shoot surface area increased with shootvolume with an exponent b of 0.75 for both species. Root lengthand the ground area explored by the roots increased with shootsurface area with b's of 0.72 for A. deserti and 0.92 for F.acanthodes. Various sized individuals had about the same ratioof root length to explored ground area, with higher values occurringfor A. deserti. Predicted water uptake averaged over the exploredground area was approximately constant over a 10⁴-fold rangein shoot surface area, suggesting that shoot size confers nointraspecific competitive advantage for water uptake. For theroot lengths per explored ground area observed in the field,water uptake was predicted to be 85 per cent of maximal; wateruptake could be increased by the production of more rain roots.When differences in shoot volume were accounted for by allometry,small plants had relatively less shoot surface area and relativelymore root length per shoot volume than did large plants, whichmay be important for the water relations of seedling establishment. Agave deserti, Ferocactus acanthodes, allometry, desert succulents, root distribution, root length, seedling growth, seedling establishment, shoot surface area, shoot volume, water uptake     

Comparative studies of hepatotoxicity and fumonisin B1 and B2 content of water and chloroform/methanol extracts of Fusarium moniliforme strain MRC 826 culture material

Fusarium moniliforme has been associated with several diseases including equine leukoencephalomalacia, human esophageal cancer and hepatotoxicity/hepatocarcinogenicity in laboratory animals. The potential health risks to animals and humans posed by F. moniliforme contaminated grains cannot be assessed until the toxins are identified and toxicologically evaluated. As part of a systematic approach to identifying the hepatotoxins produced by F. moniliforme, diets containing aqueous and chloroform/methanol (11) extracts of F. moniliforme strain MRC 826 culture material (CM) and/or the extracted CM residues were fed to male Sprague-Dawley rats for four weeks. Serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activities were increased after two and four weeks and microscopic liver lesions were found in those animals fed aqueous CM extract and the CM residue after chloroform/ methanol extraction. Fumonisins B₁ and B₂ were extracted from the CM by water, but not chloroform/ methanol, and were present in the toxic diets at concentrations of 93–139 and 82–147 ppm, respectively. Nontoxic diets contained 22 ppm fumonisin B₁ and 65 ppm fumonisin B₂.Abbreviations CM culture material - ELEM equine leukoencephalomalacia Mention of a trademark, proprietory name or vendor does not imply its approval by the US Department of Agriculture to the exclusion of others that may also be suitable.     

Characterization of different B-F (MHC class I) molecules in the chicken

B-F alloantisera recognized distinct 45-Kd molecules on peripheral red blood cells (RBC) from embryonic chickens and heterogeneous molecules of approximately 40 to 44 Kd on peripheral RBC from adult chickens, provisionally referred to as type 1 and type 2, respectively. Type 2 molecules migrated to the basic end of isoelectric focusing gels, exhibited multiple isomorphic variants, and were associated with a smaller polypeptide of approximately 11 to 12 Kd assumed to be beta-2-microglobulin. Type 1 molecules migrated to the acidic end of isoelectric focusing gels, exhibited limited heterogeneity, and were not associated with a smaller polypeptide. Type 1 and type 2 molecules were also shown to be distinct by peptide mapping and serological analyses. In addition, two distinct molecular-weight forms of the type 2 molecules were distinguished, provisionally referred to as 2A (45 Kd) and 2B (42 Kd). In vivo-derived avian erythroblastosis virus (AEV)-transformed erythroleukemia cells expressed type 2A molecules. In vitro-derived AEV-transformed erythroleukemia cells expressed very low levels of B-F molecules; however, they expressed type 2B molecules when induced to differentiate. Normal bursa-derived lymphoid cells expressed type 2A molecules, whereas normal thymus-derived lymphoid cells expressed type 2B molecules. Cloned reticuloendotheliosis virus (REV)-transformed immature lymphoid cells expressed either type 2A or type 2B molecules.     

Natural course of penicillamine nephropathy: a long term study of 33 patients

To elucidate the natural course of the nephropathy associated with penicillamine and thereby facilitate its clinical management 33 patients with rheumatoid arthritis who developed proteinuria during treatment with oral penicillamine were studied in detail throughout their renal illness. Renal biopsies were performed, and creatinine clearance and proteinuria were measured serially for 74 months (range 16-148 months). Fourteen patients developed proteinuria within six months after the start of treatment and 27 within 12 months. When treatment was stopped the proteinuria reached a median peak of 4·2 g/24 h (range 0·3-15·0 g/24 h) at one month (range 0-7 months) before resolving spontaneously by six months (12 patients), 12 months (21), or 18 months (29). In all patients but one, who developed carcinoma of the renal pelvis, proteinuria resolved by 21 months and its median duration was eight months. The median first and last measurements of creatinine clearance showed no appreciable change (80 ml/min and 78 ml/min), and no patient died from or needed treatment for renal failure. The HLA-B8 or HLA-DR3 alloantigen, or both, were identified in 10 patients. Renal biopsy specimens showed membranous glomerulonephritis in 29 patients, minimal change nephropathy in two, and electron dense deposits in the mesangial regions in two.In all the patients whose nephropathy was due solely to treatment with penicillamine the proteinuria resolved completely when the drug was withdrawn; renal function did not deteriorate, and corticosteroids were unnecessary.