Production of Pentameric Hybrid Immunoglobulins Consisting of IgA and IgM

The amylomaltase from Escherichia coli IFO 3806 was purified to homogeneity seen by SDS- polyacrylamide gel electrophoresis after DEAE-Sephadex, Ultrogel AcA 44, hydroxylapatite, and 1,6- hexane-diamine-Sepharose 4B column chromatographies. The molecular weight of the purified enzyme was 93,000 by SDS-polyacrylamide gel electrophoresis. The enzyme was most active at pH 6.5 and at 35°C, and stable up to 45°C at pH 7.0 and from pH 6.0 —7.3 at 40°C on 30min incubation. The enzyme acted on maltotetraitol, maltopentaitol, and maltosylsucrose besides maltooligosaccharides, but did not act on maltitol, maltotriitol, glucosylsucrose, isomaltose, panose, isopanose, or isomaltosyl- maltose. This enzyme did not catalyze hydrolytic action on maltotetraitol, maltopentaitol, or maltosylsucrose.     

Cellular and Vacuolar Fusion of Protoplasts Electrofused Using Platinum Microelectrodes

Protoplasts isolated from cultured cells of Coptis japonicaand Euphorbia millii were electrically fused using platinummicroelectrodes. The process involved two stages, cellular andvacuolar fusion, which are characterized respectively by transientwrinkling of the membrane and the formation of a dark-red precipitate. (Received June 12, 1987; Accepted October 13, 1987)     

Synthesis of a callosic substance during rhizoid differentiation in Spirogyra

Spirogyra living in running water is anchored to the substratum by rhizoids that form at the ends of the filaments. A new terminal cell differentiates into a rhizoid cell if the filament is injured. The mode of growth changes from diffuse to tip growth when rhizoid differentiation begins. In this study, we found that a callosic substance was synthesized during rhizoid differentiation. Decreasing the cell turgor, lowering extracellular Ca2+ or adding Gd3+, all inhibited the commencement of rhizoid differentiation as well as synthesis of the callose-like substance at the tip of the terminal cell. A callosic substance was also synthesized during formation of the conjugation tube.     

Physical and genetic characterization of the glucitol operon in Escherichia coli.

The glucitol (gut) operon has been identified in the colony bank of Clark and Carbon (A. Sancar and W. D. Rupp, Proc. Natl. Acad. Sci. USA 76:3144-3148, 1979). We subcloned the gut operon by using paCYC184, pACYC177, and pBR322. The operon, which is encoded in a 3.3-kilobase nucleotide fragment, consists of the gutC, gutA, gutB, and gutD genes. The repressor of the gut operon seemed to be encoded in the region downstream from the operon. The gene products of the gut operon were identified by using maxicells. The apparent molecular weights of the glucitol-specific enzyme II (product of the gutA gene), enzyme III (product of the gutB gene), and glucitol-6-phosphate dehydrogenase (product of the gutD gene) were about 46,000, 13,500, and 27,000, respectively, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.     

Mitogenic andadjuvant activities of polysaccharides from the cellular slime mold, Dictyostelium discoideum NC-4.

Cell surface and extracellular polysaccharide fractions obtained from Dictyostelium discoideum NC-4 cultured in bacteria-free medium showed strong B-cell mitogenic activities. Upon periodate treatment of the extra-cellular polysaccharide fraction this activity completely disappeared. The extracellular polysaccharide fraction could also enhance the antibody response in vitro against sheep red blood cells.     

Spatial and temporal variations in the light environment in a primary and selectively logged forest long after logging in Peninsular Malaysia

Key message

We could show long-term effects of logging operation in a Malaysian forest. A forest selectively logged about 50 years ago had a longer sunfleck time and a less heterogeneous light spatially than primary forests.

Abstract

We compared forest light environments between a primary lowland tropical rainforest and a rainforest selectively logged 50 years ago in the Pasoh Forest Reserve, Peninsular Malaysia using two different approaches to assess forest light environments, hemispherical canopy photographs and continuous measurements of forest photosynthetic photon flux density (PPFD) and showed clear evidence of the long-term impact of selective logging on forest light environments. The selectively logged forest canopy consisted of shorter and smaller crowns with less variations of height and crown area than the primary forest. From the canopy structural characteristics of the selectively logged forest, we predicted that the selectively logged forest has brighter and more homogeneous forest light than the primary forest. Both hemispherical canopy photographs and measurements of PPFD showed that the selectively logged forest had more open canopies and longer sunfleck time than the primary forest. A significantly smaller variance of canopy openness and a shorter autocorrelation range in the selectively logged forest than in the primary forest were found, indicating that the selectively logged forest had a less heterogeneous light environment spatially than the primary forest. Therefore our predictions were confirmed. The results suggest that different light environments for the primary forest and forest after logging might promote different forest dynamics between them.     

Fundamental Studies on the Aerobic Fermentation

The oxygen uptake rate of aggregated mycelia is decreased to an extent which, in the case of a typical spherical aggregate, could be estimated depending on its diameter, mycelial density, oxygen diffusivity, and so forth. Equations were presented in this paper to evaluate the oxygen uptake rate of an mold pellet. A favorable agreement was found between the calculation and the experiment.