The relationships among exercise behavior, functional ADL, and psychological health in the elderly

The purpose of this study was to examine the relationships among exercise behavior, the ability to live independently as assessed by functional activities of daily living (ADL), and psychological health as measured by the Philadelphia Geriatric Center morale scale, using data from 202 elderly residents aged 70 and living in their own home. The main results obtained from the analysis were as follows. 1. Exercise behavior had a significant effect on functional ADL. In particular, subjects who had been exercising regularly for 6 months or longer had higher functional ADL than subjects who did not exercise. 2. For psychological health, the functional ADL level was statistically significant, whereas exercise behavior was not. 3. Multiple regression analysis showed a positive and significant association between psychological health and functional ADL, but not between psychological health and exercise behavior, gender or family type. The results of this study demonstrated that elderly people's efforts to maintain and enhance their psychological health play important roles in their ability to live independently, and that regular exercise is necessary to an elderly person's ability to live independently.     

Molecular cloning of groESL locus, and purification and characterization of chaperonins, GroEL and GroES, from Bacillus brevis

The groESL locus of a protein-hypersecreting bacterium, Bacillus brevis, was cloned by PCR using primers designed based on the DNA sequence of a B. subtilis homolog. GroEL protein was purified to apparent homogeneity and its ATPase activity was characterized: it hydrolyzed ATP, CTP, and TTP in this order of reaction rate, and its specific activity for ATP was 0.1 micromole/min/mg protein. Purified GroEL forms a tetradecamer. GroEL was estimated to contain 22% alpha-helix, 24% beta-sheet, and 19% turn structures, by CD measurement. GroES protein was also highly purified to examine its chaperonin activity. GroEL protected from thermal inactivation of and showed refolding-promoting activity for malate dehydrogenase, strictly depending on the presence of ATP and GroES.     

A role of methionine 100 in facilitating PYP(M)-decay process in the photocycle of photoactive yellow protein

PYP (photoactive yellow protein) is a photoreceptor protein, which is activated upon photo-isomerization of the p-coumaric acid chromophore and is inactivated as the chromophore is thermally back-isomerized within a second (in PYP(M)-to-PYP(dark) conversion). Here we have examined the mechanism of the rapid thermal isomerization by analyzing mutant PYPs of Met100, which was previously shown to play a major role in facilitating the reaction [Devanathan, S. et al. (1998) Biochemistry 37, 11563-11568]. The mutation to Lys, Leu, Ala, or Glu decelerated the dark state recovery by one to three orders of magnitude. By evaluating temperature-dependence of the kinetics, it was found that the retardation resulted unequivocally from elevations of activation enthalpy (DeltaH( double dagger )) but not the other parameters such as activation entropy or heat capacity changes. Another effect exerted by the mutations was an up-shift of the apparent pK(a) of the chromophore [the pK(a) of a titratable group (X) that controls the pK(a) of the chromophore] in the PYP(M)-decay process. The pK(a) up-shift and the DeltaH( double dagger ) elevation show an approximately linear correlation. We, therefore, postulate that the role of Met100 is to reduce the energy barrier of the PYP(M)-decay process by an indirect interaction through X and that the process is thereby facilitated.     

Production of transgenic chimera rabbit fetuses using somatic cell nuclear transfer

We produced aggregate chimeric embryos between blastomeres from the somatic cell nuclear transfer (SCNT) embryos and blastomeres from normal embryos. The SCNT embryos were produced by fusing enucleated oocytes with GFP gene introduced fibroblast cells, which were derived from a day 16 fetus. GFP gene-introduced fibroblast cells were cultured and passaged four to 12 times over a period of 45-79 days before SCNT. After transferring them into pseudopregnant recipient rabbits, the 15-day postcoitus fetuses were collected. We examined the existence of the cells derived from SCNT embryos in the fetus stage of pregnancy to detect the GFP gene. Fetuses that were not collected continued to develop into newborn rabbits. Two hundred and thirty-six chimeric embryos were produced using 39 SCNT morula stage embryos, and these embryos were transferred to 11 recipient rabbits. As a result, 27 normally developed and 16 degenerated concepti were obtained. The GFP gene-positive signals were detected in one of the fetuses, two of the placentae, and two of the degenerated concepti. In this study, we found that the rabbit SCNT embryos have the ability to develop and differentiate in vivo. We also demonstrated a novel method of producing a transgenic rabbit using SCNT.     

Effects of targeted overexpression of pleiotrophin on postnatal bone development

Pleiotrophin (PTN) is an extracellular matrix-associated growth/differentiation factor that, in post-natal life, is found mainly in bone and brain. Bone development was investigated in ptn-overexpressing mice between 1 and 30 weeks. In transgenics and controls, PTN (and its receptor syndecan-3) was synthesized by osteoblasts and was present in striated muscle. ptn over-expression enhanced intramembranous bone formation and had multiple effects on long-term bone growth. The pubertal growth spurt did not take place in transgenic mice, in which the growth trajectory was steady and continuous until 25 weeks. By 30 weeks, transgenic and control mice were of the same size, but the calcium content/mg bone was approximately 10% higher in the transgenics. PTN was also localized in growth plate and articular chondrocytes, but only in transgenic mice. In these, synthesis of type I collagen by articular chondrocytes was observed, as well as an encroachment of subchondral bone into the articular cartilage. The results suggest that PTN has multiple roles during in vivo bone formation and remodeling, probably acting as a co-factor or accessory protein that modulates the effects of primary signaling molecules.     

Detection of 3-methoxy-4-hydroxyphenylglycol in rabbit skeletal muscle microdialysate

A high-performance liquid chromatography with electrochemical detection (HPLC-ED) method is described for determination of 3-methoxy-4-hydroxyphenylglycol (MHPG) in microdialysate from the skeletal muscle interstitial space. Using a microdialysis technique, we sampled 30 microl dialysate from the skeletal muscle interstitial space and injected dialysate directly into HPLC-ED system. The control MHPG concentration of dialysate was 213+/-18 pg/ml. The MHPG concentrations were reduced by entacapone (catechol-O-methyltransferase inhibitor, COMT), augmented by local infusion of dihydroxyphenylglycol. This system offers a new possibility for simple, rapid monitoring of MHPG as an index of COMT activity in skeletal muscle.     

Production of D-arabitol by Metschnikowia reukaufii AJ14787

A potent producer of D-arabitol was isolated by screening of natural sources and identified as Metschnikowia reukaufii AJ14787. Resting cells of this strain can efficiently produce D-arabitol from D-glucose with a weight yield of more than 60%, and can also produce D-arabitol from several other types of sugars such as polyols, ketoses, and aldoses. To improve productivity, various culture conditions such as temperature and the concentrations of D-glucose and nitrogen sources were examined. Under optimal conditions, 206 g/l of D-arabitol was produced from D-glucose with a weight yield of 52% in 100 hours.     

l-Leucine 5-hydroxylase of Nostoc punctiforme is a novel type of Fe(II)/α-ketoglutarate-dependent dioxygenase that is useful as a biocatalyst

l-Leucine 5-hydroxylase (LdoA) previously found in Nostoc punctiforme PCC 73102 is a novel type of Fe(II)/α-ketoglutarate-dependent dioxygenase. LdoA catalyzed regio- and stereoselective hydroxylation of l-leucine and l-norleucine into (2S,4S)-5-hydroxyleucine and (2S)-5-hydroxynorleucine, respectively. Moreover, LdoA catalyzed sulfoxidation of l-methionine and l-ethionine in the same manner as previously described l-isoleucine 4-hydroxylase. Therefore LdoA should be a promising biocatalyst for effective production of industrially useful amino acids.