Agricultural Activities of a Meadow Eliminated Plant Litter from the Periphery of a Farmland in Inner Mongolia,China

The purpose of our investigation was to clarify the effects of agriculture on the process of loss of litter at the periphery of a farmland. This study revealed the generation process of an ecologically unusual phenomenon that is observed around cropland in semi-arid regions. We hypothesized that the vegetation around a farmland cannot supply plant litter to the ground surface because the ecological structure has been changed by agricultural activities. The study was conducted at Xilingol steppe, Xilingol League, Inner Mongolia Autonomous Region, China. Four study lines were established from the edge of an arable field to the surrounding meadow and parallel to the wind direction during the strong wind season. Key measurement for each line was set at the border between the farmland and steppe. Four study sites were set at intervals along each line. Plant litter, soil particle size distribution, plant species composition, plant volume, and species diversity were investigated. Despite using the same mowing method at the meadows of all study sites, the litter at the only periphery of the farmland completely disappeared. Soil particle size distribution in steppe, which was adjacent to the farmland, was similar to that of the farmland. Plant community structure at the periphery of the farmland was different from that of the far side from the farmland. This implies that soil scattered from the farmland affected the species composition of the steppe. Consequently, the change in plant community structure induced litter loss because of mowing. We concluded that plant litter was lost near the farmland because of the combined effects of farming and mowing. The results support our hypothesis that the vegetation around a farmland cannot supply plant litter because the ecological structure has been changed by agricultural activities.     

Isolation and Chemical Structure of New Oxidation Product of 5-Ketogluconic Acid,and a Hypothetical Pathway from Glucose to Tartaric Acid through this New Compound

In the course of study on the mechanism of the tartaric acid formation from 5-ketogluconic acid, a new intermediary substance with mauve color to Abdel-Akhel and Smith’s reagent was isolated from intact cell culture liquid. The chemical structure of this substance was determined as 1,2-dihydroxyethyl hydrogen L(+) tartrate from the results of hydrolysis experiments and from the identifications of the constituents of the molecule, and named “pretaric acid.” Tartaric acid was evidently produced from pretaric acid by intact cell culture. Clearly, then, pretaric acid appears to be an intermediate in the formation of tartaric acid from 5-ketogluconic acid. The authors assumed that in the formation of pretaric acid from 5-ketogluconic acid, a Baeyer-Villiger type oxidation occurred.     

Fractal property of eye movements in schizophrenia

 On the basis of a temporal model of animal behavior we conducted temporal analysis of eye movements in schizophrenic subjects (n=10) and normal controls (n=10). We found a fractal property in schizophrenic subjects, the fixation time of eye movement during reading ambiguous and difficult sentences showing a clear inverse power law distribution. An exponential distribution of a nonfractal nature was found in normal controls. Received: 21 July 1995/Accepted in revised form: 30 April 1996     

Conformation of NAD+ bound to allosteric L-lactate dehydrogenase activated by chemical modification

On modification of arginine residues with 2,3-butanedione, the Thermus caldophilus L-lactate dehydrogenase is converted to an activated form that is independent of an allosteric effector, fructose 1,6-bisphosphate (Fru-1,6-P2). The conformation of NAD+ bound to the modified enzyme in the absence of Fru-1,6-P2 was investigated by means of proton NMR, analyzing the time dependence of the transferred nuclear Overhauser effect (TRNOE) and TRNOE action spectra. The inter-proton distances determined on TRNOE analysis indicated that both the nicotinamide riboside moiety and the adenosine moiety of NAD+ were in the anti conformation, the ribose rings being in the C3'-endo form. This conformation was almost the same as that of NAD+ bound to the native enzyme-Fru-1,6-P2 complex, rather than that of NAD+ bound to the free native enzyme. These results suggest that the C3'-endo-anti form of the enzyme-bound NAD+ is essential for the activation of the T. caldophilus L-lactate dehydrogenase.     

Dermatan sulfate isomers in human articular cartilage characterized by high-performance liquid chromatography

The Constituents of dermatan sulfate isomers in human articular cartilage were studied at the disaccharide level by high-performance liquid chromatography. Appreciable amounts of dermatan sulfate components, i.e., dermatan sulfate, chondroitin sulfate types G and B, could be detected after digestion with chondroitinases-B or -ABC. The oversulfated dermatan sulfate isomers were isolated only after digestion with chondroitinase-ABC but not with the AC-lyase. The dermatan sulfate isomers were found to be markedly increased in weight loading parts of articular cartilage. It is postulated that the dermatan sulfate isomers are formed as a result of the weight loading reaction, which may be responsible for the fibrosis of articular cartilage.     

An ultrastructural study of HeLa cell invasion with Salmonella typhi GIFU 10007

Scanning electron micrograph of HeLa S3 monolayered cells, inoculated with viable bacteria of a Salmonella typhi strain GIFU 10007, revealed that the extended microvilli tangled the bacteria within 10 min after inoculation. The micrographs of HeLa cells, at 1 hr after inoculation, indicate the following: shortening of bacterium-attached microvilli, subsiding of tangled bacteria into microvilli bush, and then attachment of bacterial soma to cell surface making the cell membrane depressed. The transmission electron micrographs, at 1 hr after inoculation, demonstrated the findings of interaction between HeLa cell and S. typhi 10007, similar to those observed on scanning electron micrographs. Hair-like fine structures from the soma of challenge organisms were also observed. They were in contact with HeLa cell microvilli and cell membrane. The bacteria were first partially and then totally surrounded by the HeLa cell plasma membrane. One, two, or several bacteria with intact outer membrane were enclosed in intracytoplasmic membrane-bound vacuoles. Fragmented vacuolar membrane was still visible around the intracellularly accumulated bacteria at 24 hr after inoculation. The viable cells of S. typhi 10007 are regarded as internalizing into HeLa cells by a process of endocytosis and to multiply within the membrane-bound vacuoles.