AGGREGATION OF SOIL PARTICLES BY ALGAE1

Chlorella pyrenoidosa Chick (Indiana University Number 252), Nostoc commune Vaucher (I.U. 584), and Oscillatoria prolifica (Grev.) Gomont (I.U. 1270) were grown separately on Peoria loess soil material to measure their effects on the water stability of soil aggregates. Each alga significantly (10% LSD) increased the percentage of soil aggregates after 6 weeks of incubation as compared with the soil without algae. Oscillatoria, Chlorella, and Nostoc increased water stability of aggregates >74 μ in diameter by 3.4, 1.1, and 0.6%, respectively. Nostoc and Oscillatoria produced measurable water stable aggregates in the 1000–2000 μ diameter range; Chlorella formed them in the 500–1000 μ range, while the control soil showed no aggregates >295 μ.     

Regulation of IgM and IgD synthesis in B lymphocytes. I. Changes in biosynthesis of mRNA for mu- and delta-chains

Although IgD is expressed on the surface of resting B cells at a higher density than IgM, we determined that both the steady-state level and the biosynthetic rate of mu m-mRNA is higher than that of delta m-mRNA, suggesting that translational or post-translational processing of the Ig heavy chains may modulate the expression of cell surface Ig. After B cell activation by LPS, delta m-mRNA decreases drastically, accounting for the observed decrease in expression of IgD. Concomitantly, a dramatic increase in the level of mu s- and gamma s-mRNA corresponds to the observed increase in secretion of these Ig isotypes in LPS-stimulated cells.     

Identical reactivity of monoclonal antibodies HNK-1 and NC-1: conservation in vertebrates on cells derived from the neural primordium and on some leukocytes

NC-1 and HNK-1, two mouse monoclonal antibodies raised against quail ciliary ganglion and a human leukemic cell-line, respectively, were found to display the same pattern of reactivity. Species investigated included human, rodents, birds and amphibians. In 1- to 3-day-old avian embryos, migrating crest cells are stained, whereas in older animals neuroepithelial cells and neurons are labelled. Staining with fluorescein isothiocyanate-conjugated NC-1 is blocked by preincubation with HNK-1. In immunoblot analyses both antibodies recognize the same pattern of bands which are different in central and peripheral nervous systems and vary during development. Thus, HNK-1/NC-1 provides a useful tool for investigating the ontogeny of neural and lymphocytic cells carrying this determinant, which, in view of its high degree of conservation during vertebrate evolution, may play an important part within the haematopoietic and nervous systems.     

Complexes of bivalent cations with neryl and geranyl pyrophosphate: Their role in terpene biosynthesis

Kinetic analysis of the nonenzymic solvolysis of neryl and geranyl pyrophosphate (NPP and GPP, respectively) showed that the dissociation constants of the bis-metallic complexes with Mg²⁺ and Mn²⁺ were larger for NPP than for GPP by approximately one order of magnitude. Rate constants for reaction of the bis-metallic complexes were larger for NPP than for GPP. Qualitatively similar behavior was observed with complexes of Co²⁺. Extents of elimination and cyclization were increased by metal ions. Carbocyclase-catalyzed formation of cyclic monoterpene hydrocarbons in the presence of Mg²⁺ involved bis-metallic complexes as the “true” substrates.     

Chemolithotrophic ATP synthesis and NAD(P) reduction in Thiobacillus tepidarius and T. versutus

Thiosulphate-dependent reduction of NAD and NADP in intact cells of Thiobacillus tepidarius and T. versutus was severely inhibited or abolished by FCCP at concentrations that did not affect ATP synthesis over the same time scale. Thiosulphate-dependent ATP synthesis in T. tepidarius was abolished by the ATPase inhibitor DCCD, which did not affect NAD or NADP reduction at the concentrations tested. These results indicate that energy-dependent NAD(P) reduction using reversal of electron transfer from cytochrome b or c in thiobacilli is directly driven by the p generated by thiosulphate oxidation, and does not require the participation of ATP. While NAD(P) reduction and ATP synthesis are thus both effected by sulphur compound oxidation, there is no obligatory link between them.Abbreviations CCCP carbonyl cyanide m-chlorophenylhydrazone - DCCD dicyclohexylcarbodiimide - DNP 2,4-dinitrophenol - G-6-P glucose 6-phosphate - FCCP carbonylcyanide p-fluoromethoxyphenylhydrazone     

Taxonomic status of the extinct Banff longnose dace,Rhinichthys cataractae smithi,of Banff National Park,Alberta

Synopsis Study of 314 specimens of Rhinichthys cataractae from British Columbia, Alberta, and Wyoming, lead to the following conclusions: (1) Rhinichthys cataractae smithi Nichols,1916, is a valid subspecies, endemic to Cave and Basin Hotsprings and distinguished by 48–58 as opposed to 58–74 lateral line scales; (2) between 1925 and 1971, R. c. smithi hybridized with the eastern subspecies R. c. cataractae (Valenciennes,1842) from the Bow River and by 1981 the former had undergone almost complete introgression and was virtually extinct; (3) probable factors leading to this are introduction of tropical fishes into the hotsprings and periodic reduction of inflow from the hotsprings; (4) the closest relative of R. c. smithi is R. c. cataractae, rather than the westslope longnose dace (without a scientific name) inhabiting the Pacific basin; (5) the low number of lateral line scales of R. c. smithi may be a pleomeristic response to dwarfing; (6) R. c. smithi develops breeding tubercles at sizes as small as 21.1 mm SL, whereas R. c. cataractae develop them at 36.3 mm SL in Alberta; (7) introductions should not be made into a body of water prior to the study of its native fishes and consultation with experts in taxonomy and distribution of rare fishes. R. c. smithi is illustrated for the first time.