Advertising Missionaries

Advertising Missionaries. 1996. 52 minutes, color. film by Chris Hilton and Gauthier Flounder. For more information please contact First Run/Icarus Films, 153 Waverly Place, New York, NY 10014.     

Morphometric Variation and Biogeography of Ogwa menzeli and Criconema sphagni

Morphometrics of Ogma menzeli from woodlands in the Adirondack Mountains of New York State and in Iowa were compared. Specimens from the Adirondacks were significantly greater in mean total body length, stylet length, the b, R, and RV values, body width, and esophagus length than specimens from Iowa. The V value was significantly greater in the Iowa than in the Adirondack specimens. The two populations are considered ecotypes of O. menzeli. Criconema sphagni morphometric measurements differed significantly for the RV value (negative) and V value (positive) relative to elevation in the Adirondacks. There was a positive regression correlation for the RV value of O. menzeli and elevation in the Adirondack Mountains.     

Photosynthetic glow peaks and their relationship with the free energy changes

This paper is concerned with relating thermoluminescence to the total free-energy change, G, involved in detrapping a particular electron-hole pair as a photosynthetic sample is warmed from an initial low temperature. It extends a mathematical discussion of four possible mechanisms introduced in an earlier paper [DeVault, Govindjee and Arnold, Proc Nat'l Acad Sci USA 80: 983–987 (1983)]; here, particular attention is paid to the dependence of the absolute temperature of the maximum of a glow-peak, T _m , on the total free-energy change, G. The conclusion from the cases studied is that T _m =G/(k _B W) where G is evaluated at T _m , W is a complicated function of temperature and of thermodynamic parameters in the steps of the mechanism, and k _B is the Boltzmann constant. If the rate limiting step in the mechanism of detrapping is not preceded by any step in which G is appreciably negative, W is likely to have a value of about 33 and T _m is approximately proportional to G. Otherwise W can become much smaller and more strongly dependent on temperature and T _m is no longer proportional to G. These conclusions are of significance in lending theoretical support to the practice of inferring redox midpoint potential changes from shifts in T _m .     

THE MECHANICAL HEART ON THE MEDICAL HORIZON

Progress in materials and design of a total artificial heart has lengthened survival times from 1(1/2) hours in 1958 to 3 months in 1974. During those years various limiting factors were found and analyzed. Remaining limitations encountered in a 3-month survivor were localized thrombosis within the blood chambers and infection along drive lines into the mediastinum.     

The translation of rabbit hemoglobin messenger RNA in a cell-free extract from chick embryo brain

The translation of rabbit hemoglobin messenger RNA in an unfractionated cytoplasmic extract from chick embryo brain was studied. This translation was not dependent upon reticulocyte-specific factors. An analysis of the product synthesized in vitro with the embryo brain cell-free extract and rabbit hemoglobin messenger RNA by carboxymethyl cellulose chromatography showed that the system was capable of synthesizing both the α and β globin chains. Analysis of the tryptic peptides of the in vitro synthesized α chain by ion-exchange chromatography showed that the embryo brain extract with rabbit hemoglobin messenger RNA was capable of synthesizing the complete α chain of rabbit hemoglobin. The results suggest that no stringent tissue-specific controls exist for the translation of globin messenger RNA and were discussed in this context.     

Ordination of some littoral benthic communities in Bear Lake,Utah-Idaho

Summary Bottom invertebrate communities were compared along the western shoreline of a large oligotrophic lake (Bear Lake, Utah-Idaho). A technique of community ordination was used for the comparisons. Ordination indicated that differences among stations were associated with local differences in bottom type. The bottom type was apparently influenced by isolation from lake currents, nutrient additions, and increased amounts of fine sediments and organic matter. The amount of silt+clay was the most important sediment factor affecting the invertebrate communities. Most communities were dominated by a small species of larval chironomid, Tanytarsus.     

Regulation of argF mRNA synthesis,performed in vitro

The specific synthesis of $\text{arg}$F mRNA directed by the $\text{arg}$F gene carried on the specialized transducing bacteriophage $\text{λh80C}{}_1\text{857darg}$F, performed $\text{in vitro}$, is described with the use of an S180 extract from a strain carrying $\text{arg}$R^?. Synthesis of $\text{arg}$F mRNA is biphasic at approximately 7 minutes. The regulation of $\text{arg}$F mRNA synthesis by the specific arginine holorepressor present in an S180 extract prepared from a strain carrying the $\text{arg}$R⁺ allele is described.     

Extracellular Enzyme Activities during Lignocellulose Degradation by Streptomyces spp.: A Comparative Study of Wild-Type and Genetically Manipulated Strains

The wild-type ligninolytic actinomycete Streptomyces viridosporus T7A and two genetically manipulated strains with enhanced abilities to produce a water-soluble lignin degradation intermediate, an acid-precipitable polymeric lignin (APPL), were grown on lignocellulose in solid-state fermentation cultures. Culture filtrates were periodically collected, analyzed for APPL, and assayed for extracellular lignocellulose-catabolizing enzyme activities. Isoenzymes were analyzed by polyacrylamide gel electrophoresis and activity staining on the gels. Two APPL-overproducing strains, UV irradiation mutant T7A-81 and protoplast fusion recombinant SR-10, had higher and longer persisting peroxidase, esterase, and endoglucanase activities than did the wild-type strain T7A. Results implicated one or more of these enzymes in lignin solubilization. Only mutant T7A-81 had higher xylanase activity than the wild type. The peroxidase was induced by both lignocellulose and APPL. This extracellular enzyme has some similarities to previously described ligninases in fungi. This is the first report of such an enzyme in Streptomyces spp. Four peroxidase isozymes were present, and all catalyzed the oxidation of 3,4-dihydroxyphenylalanine, while one also catalyzed hydrogen peroxide-dependent oxidation of homoprotocatechuic acid and caffeic acid. Three constitutive esterase isozymes were produced which differed in substrate specificity toward α-naphthyl acetate and α-naphthyl butyrate. Three endoglucanase bands, which also exhibited a low level of xylanase activity, were identified on polyacrylamide gels as was one xylanase-specific band. There were no major differences in the isoenzymes produced by the different strains. The probable role of each enzyme in lignocellulose degradation is discussed.