A Function of 40 kDa Outer Membrane Protein in Serratia marcescens

The function of one of the outer membrane proteins of Serratia marcescens was investigated. S. marcescens with an abundant 40 kDa outer membrane protein was induced to form spheroplast at a high rate in an isotonic medium in the presence of calcium, although the spheroplasts were generally fragile in the isotonic environment. The degree of spheroplast induction was correlated to the amount of the 40 kDa protein present in the membrane. In the 40 kDa proteinless mutant strains, the spheroplast induction rate was remarkably decreased. Autoradiography of the outer membrane revealed the presence of a calcium-binding protein as a radioactive band whose position coincided with the 40 kDa protein. These results suggest that the 40 kDa protein has an important role in maintaining the structural integrity of the cell wall against osmotic shock.     

The Degradation of Isopropylbenzene and Isobutylbenzene by Pseudomonas sp.

To clarify biodegradation pathways of isoalkyl substituted aromatic hydrocarbons, oxidation products of isopropylbenzene and isobutylbenzene by Ps. desmolytica S449B1 and Ps. convexa S107B1 were examined.

Oxidation products from isopropylbenzene were determined to be 3-isopropylcatechol and (+)-2-hydroxy-7-methyI-6-oxooctanoic acid. Isobutylbenzene was also oxidized to 3-isobutylcatechol and (+)-2-hydroxy-8-methyl-6-oxononanoic acid by the same strains.

From these results, the existence of an unknown reductive step in the degradation of these isoalkyl substituted aromatic hydrocarbons and the initial oxidation of these aromatic hydrocarbons by the strains were made clear. The degradation pathways of isopropylbenzene and isobutylbenzene by these strains were discussed.     

Effects of thyrotropin on thyroid chromatin: Enhanced sensitivity to micrococcal nuclease and increased nuclear protein phosphorylation

Thyroid slices were incubated with or without TSH for 2 or 5 h. Nuclei were then prepared, subjected to mild digestion with micrococcal nuclease, and centrifuged at 1200 × g. The amount of DNA in 1200 × g supernatants was increased by TSH at 5 h, but not at 2 h. In parallel studies, thyroid slices were incubated with ³²P_i and labeling of acid-soluble nuclear proteins was examined. TSH-dependent increases in labeling of histones H1 and H3, and of the high mobility group protein HMG 14, were observed at 2 h; however, there were no apparent changes in TSH-dependent labeling between 2 and 5 h, in nuclease-sensitive or in bulk chromatin. These results suggest that the observed TSH-dependent changes in the micrococcal nuclease-sensitivity of thyroid nuclear chromatin were not induced directly by changes in the phosphorylation of the histones or HMG 14.     

Demonstration of bacterium-free very rapid reverse genetics system using mumps virus

The reverse genetics system is a very powerful tool for analyzing the molecular mechanisms of viral propagation and pathogenesis. However, full-length genome plasmid construction is highly time-consuming and laborious, and undesired mutations may be introduced by Escherichia coli. This study shows a very rapid E. coli-free method of full-genome construction using the mumps virus as an example. This method was able to reduce dramatically the time for full-genome construction, which was used very efficiently for virus rescue, from several days or more to ~2 days, with a similar accuracy and yield to the conventional method using E. coli/plasmid.     

Saccharum × Miscanthus intergeneric hybrids (miscanes) exhibit greater chilling tolerance of C4 photosynthesis and postchilling recovery than sugarcane (Saccharum spp. hybrids)

Although commercial sugarcane (Saccharum spp. hybrid) produces large biomass yields, its lack of cold tolerance limits its cultivation to the tropics and subtropics. In contrast, sugarcane's close relative, Miscanthus, tolerates low temperatures. We studied 18 miscane genotypes, derived from hybridizations between two genotypes of sugarcane and two genotypes of Miscanthus (one each of M. sinensis and M. sacchariflorus). In an initial greenhouse experiment on long‐duration chilling stress (12–13°C day/7–9°C night), photosynthetic rates of the Miscanthus parents were significantly higher than the sugarcane parents after 7 days of chilling and were more than double by 14 days. The Miscanthus also retained more of their prechilling (22–25°C day/13–15°C night) photosynthetic rates (68%–72% 7 days, 64%–66% 14 days) than the sugarcanes (27% 7 days, 19%–20% 14 days). Seven of 18 miscanes exhibited higher photosynthetic rates than their sugarcane parents after 7 days of chilling, whereas after 14 days only four miscane genotypes had significantly higher photosynthetic rates than their sugarcane parents, but notably two of these did not differ from their highly tolerant Miscanthus parents. In a subsequent growth chamber experiment to evaluate short‐duration chilling stress and postchilling recovery, three miscanes representing the range of responses observed in the greenhouse experiment were compared with their parents. After 4 days of chilling (12/7°C day/night), the miscanes retained between 45% and 60% of their prechilling photosynthetic rate, with the best entry not significantly different from its Miscanthus parent (66%), and all three miscanes performed significantly better than the sugarcane parents (32%–33% for sugarcanes). After 7 days of postchilling recovery (26/18°C day/night), the Miscanthus parents and two of the miscanes fully recovered their prechilling photosynthetic rates but the sugarcane parents only recovered 69%–73% of their prechilling rates. Thus, genes from Miscanthus can be used to improve chilling tolerance of sugarcane via introgression.     

Alterations of Hepatic Metabolism in Chronic Kidney Disease via D-box-binding Protein Aggravate the Renal Dysfunction

Chronic kidney disease (CKD) is associated with an increase in serum retinol; however, the underlying mechanisms of this disorder are poorly characterized. Here, we found that the alteration of hepatic metabolism induced the accumulation of serum retinol in 5/6 nephrectomy (5/6Nx) mice. The liver is the major organ responsible for retinol metabolism; accordingly, microarray analysis revealed that the hepatic expression of most CYP genes was changed in 5/6Nx mice. In addition, D-box-binding protein (DBP), which controls the expression of several CYP genes, was significantly decreased in these mice. Cyp3a11 and Cyp26a1, encoding key proteins in retinol metabolism, showed the greatest decrease in expression in 5/6Nx mice, a process mediated by the decreased expression of DBP. Furthermore, an increase of plasma transforming growth factor-β1 (TGF-β1) in 5/6Nx mice led to the decreased expression of the Dbp gene. Consistent with these findings, the alterations of retinol metabolism and renal dysfunction in 5/6Nx mice were ameliorated by administration of an anti-TGF-β1 antibody. We also show that the accumulation of serum retinol induced renal apoptosis in 5/6Nx mice fed a normal diet, whereas renal dysfunction was reduced in mice fed a retinol-free diet. These findings indicate that constitutive Dbp expression plays an important role in mediating hepatic dysfunction under CKD. Thus, the aggravation of renal dysfunction in patients with CKD might be prevented by a recovery of hepatic function, potentially through therapies targeting DBP and retinol.     

Relationship between postural stability and fall risk in elderly people with lumbar spondylosis during local vibratory stimulation for proprioception: a retrospective study

Abstract

Purpose: Reduced proprioception affects fall risks in elderly people with lumbar spondylosis. The decrease in proprioception in the trunk or lower legs may contribute to a decline in postural stability. We aimed to investigate the association between proprioceptive postural stability and fall risks in elderly individuals with lumbar spondylosis.

Materials and Methods: In this retrospective study, the centre-of-pressure displacement was determined in elderly individuals with lumbar spondylosis during upright stance while standing on a Wii Balance Board with their eyes closed (fall-risk group, n?=?55; non-fall-risk group, n?=?60). Vibratory stimulations at 30?Hz were applied to the lumbar multifidus and gastrocnemius to evaluate the relative contributions of proprioceptive signals used in postural control (relative proprioceptive weighting ratio).

Results: Compared with the non-fall-risk group, the fall-risk group displayed a high relative proprioceptive weighting ratio (p?=?0.024). Relative proprioceptive weighting ratio (odds ratio, 1.1; 95% confidence interval: 1.004–1.109) was independently associated with fall risks after adjusting for confounding factors. Among variables related to fall risk, the relative proprioceptive weighting ratio was a significant factor (p?<?0.035).

Conclusion: The fall-risk group of elderly individuals with lumbar spondylosis was dependent on the ankle strategy. The fall risk in elderly people with lumbar spondylosis could be due to over-dependence on the input from muscle spindles in the gastrocnemius.     

Highly sensitive chelating agents for histochemical staining of rare earth metals

In tissues, bromopyridylazo-diethylaminophenol has been found to be capable of staining very small amounts of rare earth metals, particularly praseodymium, terbium, dysprosium, holmium, ytterbium, and lutetium. Differentiation of a target metal from interfering metals was achieved using masking agents, polyphosphates and aminopolycarboxylic acids. Accepted: 1 June 1999