Transfer of phosphatidylcholine facilitated by a component of human plasma

A constituent of lipoprotein-free (p greater than 1.21) human plasma from normolipemic donors facilitates the transfer of diacyl phosphatidylcholine from unilamellar egg yolk phosphatidylcholine liposomes to liver mitochondria. The active component is heat labile, has a hydrated density greater than 1.25 and an apparent molecular weight of more than 100 000. The presence of this protein in plasma may facilitate movement of diacylphospholipids between the surfaces of lipid-containing particles such as lipoproteins and erythrocytes. Knowledge of the properties and behavior of this protein are important in designing methods of drug therapy based on encapsulation in biodegradable lipid vesicles.     

Coastal vegetation on the Western, Southern, and Eastern coasts of South Korea

We used the Braun-Blanquet method to study the vegetation of coastal wetlands in South Korea. Three habitat types were found, i.e., salt marshes, salt swamps, and sand dunes. These plant communities were classified as: 1) two groups (five associations each) in the salt marshes that comprised either annual herbaceous halophytes (ClassThero-Salicornietea), or biennial/perennial herbaceous species (ClassAsteretea tripolii); 2) one group in the salt swamps consisting of five hydrophilous halo-tolerant associations (ClassPhragmitetea); and 3) three groups in the sand dunes, including one association of annual herbaceous halophytes (ClassSalsoletea komarovii), seven associations of herbaceous perennial halophytes (ClassGlehnietea littoralis), and one association of shrub perennial halophytes (ClassVrticetea rotundifoliae). These three habitat types accounted for the majority of the six main classifications of coastal vegetation distributed in South Korea.     

Wet spinning of silk polymer. II. Effect of drawing on the structural characteristics and properties of filament

Regenerated silk fibroin (SF) filaments were prepared by the wet spinning technique. The rheological behavior of the SF dope solution prepared with formic acid was examined and the drawing effect on the structural characteristics and mechanical properties of SF filament was comparatively studied with those of natural silk fiber. SF dope exhibited shear thinning, but, as the dope concentration increased, the effect of shear thinning decreased, an indication that a higher concentration of dope solution will result in good spinnability. Wet-spun SF filaments exhibited a uniform and circular cross-sectional shape and dense morphology under SEM observation. X-ray diffraction (XRD) results revealed that the crystallinity of wet-spun regenerated filaments was hardly affected by the draw ratio, whereas the crystalline and amorphous orientation of regenerated SF filament showed different features depending on the drawing. The crystalline orientation of regenerated filaments increased with an increase of draw ratio and was lower than that of natural silk fiber. On the contrary, the amorphous orientation was constant throughout 1X-5X draw ratios, after an abrupt increase at 1X, and was higher than that of natural silk fiber. These differences in the orientation behaviors are attributed to the different spinning mechanisms involved. The tensile property was strongly dependent on the draw ratio. The breaking strength and elongation of the regenerated filament at 5X draw ratio were 2.2 g/day and 17%, respectively.     

Coarse woody debris mass and nutrients in forest ecosystems of Korea

Coarse woody debris (CWD) is an essential component of forests. However, quantification of both the mass and nutrient content of CWD within a given environment tends to be a fairly labor-intensive proposition that requires long-term studies to be conducted for viable data to be obtained. As a result, various aspects of CWD in forest ecosystems remain somewhat poorly understood. In this review, we have compiled all available estimates of CWD mass and nutrients from both coniferous and deciduous forests in Korea. The CWD mass data varied substantially by forest type, age, location, and sampling time, ranging from 1.5 to 24.5 Mg ha⁻¹, and for the amount (kg ha⁻¹) of nutrients in the CWD, ranging from 3.5 to 23.6 for nitrogen (N), 0.8 to 4.7 for phosphorus (P), 3.9 to 13.3 for potassium (K), 25.9 to 30.9 for calcium (Ca), 1.4 to 4.2 for magnesium (Mg), and 0.1 to 0.6 for sodium (Na). The mass of CWD transferred from live trees to the forest floor ranged between 0.1 and 4.9 Mg ha⁻¹ year⁻¹, and these values were roughly equivalent to 26–42% of the annual litterfall inputs (2.5–10.8 Mg ha⁻¹ year⁻¹) for mixed Quercus spp. forests within the relevant region. Annual nutrients inputs (kg ha⁻¹ year⁻¹) through CWD decomposition were 0.7–1.6 for N, 0.04–0.3 for P, 0.3–1.0 for K, 1.7–3.1 for Ca, and 0.1–0.3 for Mg. Consequently, these results revealed that the ecological value of CWD for C and nutrient cycling was relatively insignificant. However, only a limited number of studies have been conducted on CWD in different coniferous or mixed deciduous forests in the region. As a direct result of this paucity of data, further long-term studies on CWD mass and nutrients in a variety of forest types are required in order to be able to evaluate accurately the ecological value of CWD on biodiversity and physical properties in Korean forest ecosystems.     

A novel continuous toxicity test system using a luminously modified freshwater bacterium

An automated continuous toxicity test system was developed using a recombinant bioluminescent freshwater bacterium. The groundwater-borne bacterium, Janthinobacterium lividum YH9-RC, was modified with luxAB and optimized for toxicity tests using different kinds of organic carbon compounds and heavy metals. luxAB-marked YH9-RC cells were much more sensitive (average 7.3-8.6 times) to chemicals used for toxicity detection than marine Vibrio fischeri cells used in the Microtox assay. Toxicity tests for wastewater samples using the YH9-RC-based toxicity assay showed that EC50-5 min values in an untreated raw wastewater sample (23.9 +/- 12.8%) were the lowest, while those in an effluent sample (76.7 +/- 14.9%) were the highest. Lyophilization conditions were optimized in 384-multiwell plates containing bioluminescent bacteria that were pre-incubated for 15 min in 0.16 M of trehalose prior to freeze-drying, increasing the recovery of bioluminescence and viability by 50%. Luminously modified cells exposed to continuous phenol or wastewater stream showed a rapid decrease in bioluminescence, which fell below detectable range within 1 min. An advanced toxicity test system, featuring automated real-time toxicity monitoring and alerting functions, was designed and finely tuned. This novel continuous toxicity test system can be used for real-time biomonitoring of water toxicity, and can potentially be used as a biological early warning system.     

Statistische Betrachtung über die Häufigkeit der Haptoglobin-Typen bei verschiedenen Krankheiten

Ohne ZusammenfassungDirektor: Prof. Dr. med. G. G. Wendt