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     

A survey of surface glycoproteins of four human squamous cell carcinoma lines

The major cell surface glycoprotein components of four new cell lines derived from human squamous cell carcinomas of the head and neck (TR126, TR131, TR138, TR146, Rupniak, H. T. et al., JNCI 75, 621-635, 1985) were identified by three complementary labelling methods. The profile of labelled glycoprotein components was very similar in the four cell lines, although quite large quantitative differences in individual bands were seen. Two galactoproteins, designated GPC-130 and GPC-80 (apparent molecular weight X 10(-3)) were labelled by galactose oxidase/NaB [3H]4 but in all four lines only GPC-130 was prominent. The cell surface galactose and N-Acetylgalactosaminyl residues of glycoproteins were quite highly sialylated, as the galactose oxidase/NaB [3H]4 reaction was increased by between 3- and 6-fold after neuraminidase treatment. The neuraminidase-galactose oxidase/NaB [3H]4 and NaIO4/NaB [3H]4 methods identified a complex profile of glycoprotein components, with very high molecular weight sialogalactoconjugates being prominent. The major sialoglycoproteins were GPC-205, GPC-175, GPC-155, GPC-90 and GPC-70 and in addition, GPC-130 and GPC-80 showed enhanced labelling. Lactoperoxidase catalyzed the iodination of a similar profile of high molecular weight glycoprotein components, with GPC-205 and GPC-175 being prominent in TR126, TR131 and TR146 but less evident in TR138. Overall, the profile of labelled glycoprotein components was similar to the pattern seen in the well differentiated transitional carcinoma lines RT112 and RT4 (Steele, J. G. et al., Biochim. Biophys. Acta. 732, 219-228, 1983).     

Comparing models and observations of shelf plankton

In a previous paper (Solow and Steele, J. Plankton Res., 17,1995), the differences between variability in zooplankton biomassand in copepod stage structure were demonstrated using datafrom the northern North Sea. Here, a model is used to describethe underlying demographic processes and the effects of interannualphysical variability. Comparison of output with observationscan test the theory and so help to reconcile the apparent contradictionbetween great variability and persistence in these populations.     

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.     

A monoclonal antibody raised to tumor-specific T cell-derived suppressor factors also recognizes T suppressor inducer factors of the 4-hydroxy-3-nitrophenyl acetyl hapten suppressor network

A monoclonal antibody (mAb), B16G, was raised from BALB/c mice immunized with affinity-purified T suppressor factors (TsF) specific for the murine mastocytoma P815. This mAb was found to bind to polyclonal TsF isolated from the spleens of tumor-bearing animals, and to the TsF released from a P815-specific T cell hybridoma. In this study, B16G was tested for its reactivity with TsF produced in the 4-hydroxy-3-nitrophenyl acetyl hapten system. The factors from three types of suppressor T cell hybridomas, each representing the immortalized analogues of the inducer T suppressor cell (Ts1), transducer suppressor cell (Ts2), and effector suppressor cell (Ts3) network populations, were tested. B16G was found to be reactive with two sources of TsF1 as assayed by enzyme-linked immunosorbent assay and delayed-type hypersensitivity bioassay. By contrast, TsF2 and TsF3 were nonreactive with B16G. These results indicate that B16G recognizes class-specific suppressor factor determinants, and that the transducer/effector factors of the network are apparently serologically distinct. Because the B16G mAb fails to recognize 4-hydroxy-3-nitro-phenyl acetyl-specific TsF3 that share idiotype-related determinants with TsF1 yet binds to TsF1 molecules that have interacted with antigen, the binding is apparently independent of the site of antigen recognition. Additionally, the results show that the tumor-specific TsF1 raised in one suppressor system share serologic determinants with anti-hapten TsF1 raised in another.     

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