The Schizosaccharomyces pombe cdc6 gene encodes the catalytic subunit of DNA polymerase δ

The cdc6 mutants of Schizosaccharomyces pombe have been classified as being defective in progression through the G2 phase of the cell cycle. We cloned an S. pombe gene that could complement the temperature-sensitive growth of the cdc6-23 mutant. Unexpectedly, the cloned gene was allelic to pol3, which encodes the catalytic subunit of DNA polymerase δ. Integration mapping confirmed that cdc6 and pol3 are identical. The cdc6-23 mutant carries one amino acid substitution in the conserved N3 region of Pol3. Received: 17 October 1996 / Accepted: 19 November 1996     

Analysis of Flow Phenomena in Gastric Contents Induced by Human Gastric Peristalsis Using CFD

This paper uses computational fluid dynamics to simulate and analyze intragastric fluid motions induced by human peristalsis. We created a two-dimensional computational domain of the distal stomach where peristalsis occurs. The motion of the gastric walls induced by an antral contraction wave (ACW) on the wall of the computational domain was well simulated using a function defined in this study. Retropulsive flow caused by ACW was observed near the occluded region, reaching its highest velocity of approximately 12 mm/s in the narrowest region. The viscosity of the model gastric contents applied in this study hardly affected the highest velocity, but greatly affected the velocity profile in the computational domain. The shear rate due to gastric fluid motion was calculated using the numerical output data. The shear rate reached relatively high values of approximately 20 s⁻¹ in the most occluded region. The shear rate profile was almost independent of the fluid viscosity. We also simulated mass transfer of a gastric digestive enzyme (pepsin) in model gastric content when peristalsis occurs on the gastric walls. The visualized simulation results suggest that gastric peristalsis is capable of efficiently mixing pepsin secreted from the gastric walls with an intragastric fluid.     

Degradation of aromatic amino acids by Rhodococcus erythropolis

A Gram-positive Rhodococcus erythropolis strain S1 was shown to assimilate aromatic amino acids such as L-phenylalanine, L-tyrosine, L-tryptophan, D-phenylalanine, D-tyrosine and D-tryptophan, which were utilized not only as the sole carbon source but also as a suitable nitrogen source. The highest growth on these aromatic amino acids occurred at a temperature of 30°C. L-Phenylalanine, L-tyrosine and L-tryptophan degradative pathways would appear to be independent, and to be induced alternatively. The strain S1 also showed the ability to assimilate peptides which consisted of only L-phenylalanine and L-tyrosine.     

Frequency of the fragile X syndrome in institutionalized mentally retarded females in Japan

Summary The fragile X [fra(X)] syndrome was screened on 190 Japanese institutionalized females with moderate to severe mental retardation. Two inmates with severe mental retardation (IQ 20) had the fra(X) chromosome in 26% and 15% of the cells examined, indicating that the prevalence of the fra(X) syndrome was about 1% in all female inmates and was about 3.27% in severely mentally retarded females with known causes. However, no female with fra(X) syndrome was found in 35 moderately retarded females. Both had brothers with the fra(X) syndrome and the prevalence was 10% in females with a family history of mental retardation. In addition, the replication study of the fra(X) chromosome in the patients supported the proposal that an excess of the early replicated fra(X) chromosome is related to the mental capacity in heterozygous females. Therefore, the fra(X) syndrome should not be ignored even in severely mentally retarded females with a family history, though the heterozygotes are commonly normal to subnormal in their mental development. in addition, the replication study of the fra(X) chromosome may help to estimate mental development in the carrier children.     

Precise identification of gene products in hearts after in vivo gene transfection, using Sendai virus-coated proteoliposomes.

Both efficient gene transfer and the exact identification of gene product are required for gene therapy. Gene transfection of green fluorescence protein (GFP) might be useful for the reporter. After in vivo cotransfection of GFP and beta-galactosidase (beta-Gal) genes in Sendai virus-coated proteoliposomes to rat hearts, we compared the sensitivity and specificity of three methods: GFP detection, histochemical staining (HC) of beta-Gal activity, and immunostaining (IS) of the beta-Gal protein. Fluorescence microscopy and double staining of HC and IS revealed that both GFP and IS were equally sensitive and fourfold superior to HC at the peak of gene expression. However, different from skeletal muscle, the GFP of transfected cardiomyocytes showed two demerits: the fluorescence quenching due to the intense staining of beta-Gal activity, and nonspecific autofluorescence from myocardium. Thus, specific IS would be so far the most reliable to identify the gene product in heart.     

The gene for tRNA(Lys) is encoded in the rapeseed (Brassica napus L.) mitochondrial DNA.

The nucleotide sequence of the gene coding for tRNA(Lys) and its flanking regions from the rapeseed mitochondrial genome are presented and compared with other known tRNA(Lys) genes from plant mitochondria. This tRNA sequence can be folded into the standard cloverleaf structure model. Also, this tRNA sequence shows less similarity with its chloroplast counterparts and therefore appears to be 'native' mitochondrial tRNA.     

Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.     

The influence of motor unit composition and stature on fractionated patellar reflex times in untrained men

The purpose of the present study was to investigate the influence of muscle fibre composition and stature on fractionated patellar reflex times in ten healthy untrained men (mean age: 23.3 years, SD 3.1; mass: 65.9 kg, SD 8.5; height: 172.3 cm, SD 5.3). Biopsies were taken from the right vastus lateralis muscle. Using staining for myofibrillar adenosine triphosphatase after pre-incubation at pH 4.3 and 4.6, muscle fibres were classified into slow twitch (ST), fast twitch, oxidative-glycolytic (FTa) and fast twitch, glycolytic (FTb) fibres. Total patellar reflex time (TRT) and its fractionated components--reflex latency (LAT) and reflex motor time (MT)--were obtained from the mean of ten trials in each subject whilst performing Jendrassik's maneuvre. The TRT, LAT and MT were 77.7 ms, SD 16.5, 23.4 ms, SD 1.3 and 54.2 ms, SD 16.3, respectively. The LAT was significantly correlated to the percentage number of ST (r = 0.758, P less than 0.05) and FTa fibres (r = -0.657, P less than 0.05), fast twitch:slow twitch ratio (r = -0.799, P less than 0.01) and to the height of the subjects (r = 0.901, P less than 0.001), whereas TRT and MT were not significantly correlated with either fibre types or the height of the subjects. From these results it can be concluded that the LAT during the patellar reflex is influenced by muscle fibre composition and the length of the sensory and/or motor nerve.