Characterization of the natural immune response of rhesus monkey CD4+ve T cells to the bacterial antigen streptolysin O (SLO)

Abstract: Rhesus monkeys show a high proliferative T cell response to the bacterial exotoxin SLO without prior immunization. The present study was undertaken to characterize this naturally present SLO-responsiveness with particular emphasis on CD4^+ve reactive T cells. It is demonstrated that the frequency of SLO-reactive cells in the circulation ranges between 1 in 75 and 1 in 610 CD4^+ve T cells as determined with limiting dilution analysis. It is also shown that induction of a good proliferative response requires Mhc-DR matching between T cell and the antigen presenting cells (APC). Stable and DR-restricted SLO-specific CD4^+ve T cell lines were generated from CD8 depleted peripheral blood mononuclear cells (PBMC). The SLO-reactive CD4^+ve cell lines are tentatively characterized as Thl-like based on the predominant production of interferon-gamma (IFN-γ) over IL-4, although this seems contradicted by the IL-4 dependent growth of the lines.     

Sodium bioenergetics in methanogens and acetogens

Abstract Recent investigations with Methanosarcina barkeri elucidated the role of sodium ions in the energy metabolism of methanogenic bacteria and provided evidence for a novel mechanism of energy transduction with Na⁺ as the coupling ion. During methanogenesis from methanol, an eletrochemical sodium gradient generated by a Na⁺/H⁺ antiporter is used as the driving force for the thermodynamically unfavourable oxidation of methanol to the formal redox level of formaldehyde. During methanogenesis from H₂+ CO₂, the reverse reaction, the reduction of formaldehyde to the level of methanol, is accompanied by a primary, electron transport-driven sodium extrusion. Acetogenesis from H₂+ CO₂ as carried out by Acetobacterium woodii is a sodium-dependent process and is accompanied by the generation of a transmembrane sodium gradient with the reduction of formaldehyde to the level of methanol as the sodium-dependent step.     

A re-examination of the cloacal sacs and gland of the blind snake,Leptotyphlops dulcis (Reptilia: Leptotyphlopidae)

The cloacal sacs of Leptotyphlops dulcis are nonglandular, posterior evaginations of the cloaca. The median cloacal gland is tubuloalveolar. Similar unpaired cloacal glands as well as paired sacs are noted in certain colubrid snakes. Terminology applied to these cloacal derivatives is discussed, and a standardization of names is provided.     

Acetogenesis and ATP synthesis in Acetobacterium itwoodii are coupled via a transmembrane primary sodium ion gradient

Abstract In cell suspensions of Acetobacterium woodii the acetyl-CoA pathway is coupled to net ATP formation. Acetate formation as well as ATP synthesis and the generation of a transmembrane sodium ion gradient are not inhibited by protonophores but by sodium ionophores. Acetogenesis from CO or formaldehyde + CO as catalyzed by inverted vesicles is coupled to sodium ion uptake. Both processes are not inhibited by protonophores but by sodium ionophores. These experiments are in accordance with the presence of a primary sodium ion pump connected to the acetyl-CoA pathway which enables the cells to synthesize net ATP by means of a Δμ _Na+ in concert with a Na⁺-translocating ATPase.