Immunolocalization of β-1-4-galactan and its relationship with lignin distribution in developing compression wood of Cryptomeria japonica

Compression wood (CW) contains higher quantities of β-1-4-galactan than does normal wood (NW). However, the physiological roles and ultrastructural distribution of β-1-4-galactan during CW formation are still not well understood. The present work investigated deposition of β-1-4-galactan in differentiating tracheids of Cryptomeria japonica during CW formation using an immunological probe (LM5) combined with immunomicroscopy. Our immunolabeling studies clearly showed that differences in the distribution of β-1-4-galactan between NW (and opposite wood, OW) and CW are initiated during the formation of the S₁ layer. At this stage, CW was strongly labeled in the S₁ layer, whereas no label was observed in the S₁ layer of NW and OW. Immunogold labeling showed that β-1-4-galactan in the S₁ layer of CW tracheids significantly decreased during the formation of the S₂ layer. Most β-1-4-galactan labeling was present in the outer S₂ region in mature CW tracheids, and was absent in the inner S₂ layer that contained helical cavities in the cell wall. In addition, delignified CW tracheids showed significantly more labeling of β-1-4-galactan in the secondary cell wall, suggesting that lignin is likely to mask β-1-4-galactan epitopes. The study clearly showed that β-1-4-galactan in CW was mainly deposited in the outer portion of the secondary cell wall, indicating that its distribution may be spatially consistent with lignin distribution in CW tracheids of Cryptomeria japonica.     

Development of social grooming between mother and offspring in wild chimpanzees

Grooming between female chimpanzees and their offspring was studied in the Mahale Mountains, Tanzania. Infants under 2 years of age rarely groomed their mothers, and mostly groomed accessible parts of their mother's bodies, if they did so. Most older adolescents reciprocated grooming with their mothers almost equally. Daughters appeared to mature socially earlier than sons, judging from the earlier ages at which a female infant began to groom her mother, groom mutually with her, and groom others. Weaning infants groomed their mothers more when they were in oestrus than when they were not. Development of the use of grooming as a means of social manoeuvring is discussed.     

Distribution of Clostridium botulinum type C in Ishikawa prefecture, and applicability of agglutination to identification of nontoxigenic isolates of C. botulinum type C.

Since deaths of waterfowls have frequently been observed in Lake Kahoku near Kanazawa city, Japan, we attempted an ecological study on Clostridium botulinum type C in four other lakes as well as Lake Kahoku. One hundred and twenty-nine (56%) of 230 soil samples collected gave rise to lethal toxicity in mice with the characteristic “wasp-waist” symptom. All of the 51 samples arbitrarily selected were neutralized by C. botulinum type C antitoxic serum. A further seasonal study throughout the year at a given shore area of Lake Kahoku disclosed that nearly all samples gave rise to toxicity due to C. botulinum type C during the autumn season when the most waterfowls congregate. Toxigenic strains of C. botulinum type C were isolated together with nontoxigenic strains that were culturally and biochemically similar to the toxigenic strains. Both the toxigenic and nontoxigenic strains were equally agglutinable by an antiserum prepared against one of the nontoxigenic strains. Further extensive studies on the specificity of the agglutination method for identification were performed with 112 strains of 46 clostridial species. None of the strains used except some strains of C. novyi type A and a strain of C. botulinum type D was agglutinable. Based on the findings for cultural, biochemical, and agglutinable properties, the nontoxigenic strains were identified as C. botulinum type C. Also, C. novyi type A isolates showing colonies covered with a small pearly layer zone but surrounded by an aberrantly wide lecithinase zone are discussed.     

Prophages integrating into prophages: A mechanism to accumulate type III secretion effector genes and duplicate Shiga toxin-encoding prophages in Escherichia coli

Bacteriophages (or phages) play major roles in the evolution of bacterial pathogens via horizontal gene transfer. Multiple phages are often integrated in a host chromosome as prophages, not only carrying various novel virulence-related genetic determinants into host bacteria but also providing various possibilities for prophage-prophage interactions in bacterial cells. In particular, Escherichia coli strains such as Shiga toxin (Stx)-producing E. coli (STEC) and enteropathogenic E. coli (EPEC) strains have acquired more than 10 prophages (up to 21 prophages), many of which encode type III secretion system (T3SS) effector gene clusters. In these strains, some prophages are present at a single locus in tandem, which is usually interpreted as the integration of phages that use the same attachment (att) sequence. Here, we present phages integrating into T3SS effector gene cluster-associated loci in prophages, which are widely distributed in STEC and EPEC. Some of the phages integrated into prophages are Stx-encoding phages (Stx phages) and have induced the duplication of Stx phages in a single cell. The identified attB sequences in prophage genomes are apparently derived from host chromosomes. In addition, two or three different attB sequences are present in some prophages, which results in the generation of prophage clusters in various complex configurations. These phages integrating into prophages represent a medically and biologically important type of inter-phage interaction that promotes the accumulation of T3SS effector genes in STEC and EPEC, the duplication of Stx phages in STEC, and the conversion of EPEC to STEC and that may be distributed in other types of E. coli strains as well as other prophage-rich bacterial species.     

Use of an activated carbon column for the synthesis of disaccharides by use of a reversed hydrolysis activity of β-galactosidase

Summary An activated carbon column was utilized for the synthesis of disaccharides by use of a reversed hydrolysis activity of an immobilized -galactosidase column in order to shift the equilibrium to the direction of condensation. The yields of lactulose and allo-lactulose from galactose and fructose, and N-acetyl lactosamine and N-acetyl allolactosamine from galactose and N-acetyl glucosamine, were 11.3% and 10.0%, respectively.     

Peroxidative injury of the mitochondrial respiratory chain during reperfusion of hypothermic rat liver

Mitochondrial dysfunction in ischemic liver has been demonstrated to be due to decrease in the intramitochondrial level of ATP and the subsequent disruption of the proton barrier of the inner membrane (Watanabe, F., Hashimoto, T. and Tagawa, K. (1985) J. Biochem. 97, 1229-1234). In this study, another injury process, impairment of the electron-transfer system, which occurred during reoxygenation of ischemic liver, was studied during reperfusion of cold preserved liver and during cold incubation of isolated rat-liver mitochondria. The sites of the respiratory chain that were sensitive to peroxidative damage were ubiquinone-cytochrome c oxidoreductase and NADH-ubiquinone oxidoreductase. These enzymic activities decreased with increase in lipid peroxidation. Incubation of submitochondrial particles with t-butyl hydroperoxide or with an NADPH-dependent peroxidation system decreased the enzymic activities of the electron-transport system. These data strongly suggested that lipid peroxidation during reoxygenation of ischemic liver impaired the electron-transfer system. Thus, mitochondria of ischemic liver suffer from two different types of injury: increase in proton permeability during anoxia, and decrease in enzymic activities of the electron-transport system during reoxygenation.