297 research outputs found
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Characterization of the role of the 3' noncoding region of turnip yellow mosaic virus RNA
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Dispersed repetitive sequences in the chloroplast genome of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
Chloroplast genomes of conifers are unusual in a
number of respects, including the possession of much
repetitive DNA. By studying the distribution and sequences
of dispersed repetitive DNA, I hoped to gain insight into
the mechanisms of chloroplast genome evolution.
I used restriction mapping and DNA sequencing to
characterize dispersed repetitive DNA in the chloroplast
genome of Douglas-fir (Pseudotsuga menziesii (Mirb.)
Franco). A chloroplast DNA clone bank was constructed in a
pUC19 plasmid vector. High stringency hybridization among
these recombinant plasmids, and to restricted chloroplast
DNA, was used to map repeat families. Dispersed repeats
were grouped into three classes: long repeat families
(around 600 bp), medium repeat families, and short repeat
families (10-20 bp). The long and medium repeats were
classified into a total of six families and placed on a
restriction site map.
Sequence analysis of one repeat family shared among
three restriction fragments revealed the presence a 633 by
inverted repeat. The repeat contains a complete transfer
RNA-Serine (GCU) gene and an open reading frame (ORF36).
This open reading frame is highly homologous with
chloroplast sequences in tobacco and liverwort. Both ends
of the repeat possess transposon-like structures. Two
copies of the dispersed repeats are located near the
endpoints of a large inversion that distinguishes Douglas-fir
and radiata pine. The third copy of the repeat is also
located near the endpoint of an inversion that occurred
during conifer evolution, and is associated with a length
mutation hotspot, and short inverted repeats; the latter
appear to be capable of forming numerous stem-loop
structures.
Sequence comparisons with tobacco cpDNA revealed that
one of the Douglas-fir chloroplast DNA clones is homologous
to three tobacco chloroplast DNA segments. These regions in
tobacco appear to have been juxtaposed in Douglas-fir by a
number of inversions and a small deletion. An 8 by
(CATCTTTT) direct repeat in tobacco is sandwiched between
two inverted sections in Douglas-fir. This repeat may be a
target sequence for homologous recombination
Overweight and Obesity-related Metabolic Disorders in Hospital Employees
BackgroundObesity is associated with metabolic disorders and cardiovascular diseases. This study investigated the relationship between overweight and obese status and the incidence of type 2 diabetes, hypertension, hyperlipidemia and hyperuricemia.MethodsThis prospective cohort study comprised 1749 hospital employees who received baseline health check-ups in 1993. Data from the 1027 participants (832 women, 195 men; mean age, 36 ± 7 years) who repeated check-ups in 2003 were used in the analysis. Relative risks (RRs) for development of metabolic disorders during follow-up associated with different body mass index (BMI) categories at baseline as defined by Asia-Pacific recommendations and the Department of Health in Taiwan were calculated after adjustment for covariates.ResultsThe prevalence of overweight and obesity at baseline check-up were 17.6% and 14.5%, respectively. Obese subjects with baseline BMI ≥ 25 kg/m2 had a significant multivariate-adjusted RR of 2.7 for hypertension, 14.8 for type 2 diabetes, 3.2 for hypertriglyceridemia, and 2.8 for hyperuricemia, compared to subjects with baseline BMI < 23.0 kg/m2. RR for diabetes was higher in women than in men, but RR for hypertriglyceridemia was higher in men. The risks of hypertension and hyperuricemia significantly increased for subjects with baseline BMI ≥ 23 kg/m2, while RRs for type 2 diabetes increased significantly for baseline BMI ≥ 24 kg/m2 and hypertriglyceridemia increased for baseline BMI ≥ 25 kg/m2. The risks attributable to obesity (baseline BMI ≥ 25 kg/m2) were 23.0% for hypertension, 70.8% for diabetes, 27.9% for hypertriglyceridemia, and 24.1% for hyperuricemia.ConclusionThis study revealed that a high prevalence of overweight and obesity was associated with significantly increased risk of development of type 2 diabetes, hypertension, hypertriglyceridemia and hyperuricemia in hospital employees, suggesting the need for programs to improve weight management
Ixora parviflora Protects against UVB-Induced Photoaging by Inhibiting the Expression of MMPs, MAP Kinases, and COX-2 and by Promoting Type I Procollagen Synthesis
Ixora parviflora with high polyphenol content exhibited antioxidant activity and reducing UVB-induced intracellular reactive oxygen species production. In this study, results of the photoaging screening experiments revealed that IPE at 1000 μg/mL reduced the activity of bacterial collagenase by 92.7 ± 4.2% and reduced the activity of elastase by 32.6 ± 1.4%. Therefore, we investigated the mechanisms by which IPE exerts its anti-photoaging activity. IPE at 1 μg/mL led to an increase in type I procollagen expression and increased total collagen synthesis in fibroblasts at 5 μg/mL. We found that IPE inhibited MMP-1, MMP-3, and MMP-9 expression at doses of 1, 5, and 10 μg/mL, respectively, in fibroblasts exposed to UV irradiation (40 mJ/cm2). Gelatin zymography assay showed that IPE at 50 μg/mL inhibited MMP-9 secretion/activity in cultured fibroblasts after UVB exposure. In addition, IPE inhibited the phosphorylation of p38, ERK, and JNK induced by UVB. Furthermore, IPE inhibited the UVB-induced expression of Smad7. In addition, IPE at 1 μg/mL inhibited NO production and COX-2 expression in UV-exposed fibroblasts. These findings show that IPE exhibits anti-inflammatory and anti-photoaging activities, indicating that IPE could be a potential anti-aging agent
Critical Neurons: optimized visual recognition in a neuronal network
In the past few decades, there have been intense debates whether the brain
operates at a critical state. To verify the criticality hypothesis in the
neuronal networks is challenging and the accumulating experimental and
theoretical results remain controversial at this point. Here we simulate how
visual information of a nature image is processed by the finite
Kinouchi-Copelli neuronal network, extracting the trends of the mutual
information (how sensible the neuronal network is), the dynamical range (how
sensitive the network responds to external stimuli) and the statistical
fluctuations (how criticality is defined in conventional statistical physics).
It is rather remarkable that the optimized state for visual recognition,
although close to, does not coincide with the critical state where the
statistical fluctuations reach the maximum. Different images and/or network
sizes of course lead to differences in details but the trend of the information
optimization remains the same. Our findings pave the first step to investigate
how the information processing is optimized in different neuronal networks and
suggest that the criticality hypothesis may not be necessary to explain why a
neuronal network can process information smartly.Comment: 11 pages, 4 figures in the main text and 3 figures in the
Supplementary Informatio
Maintaining the structural integrity of thebamboo mosaic virus 3′ untranslated region isnecessary for retaining the catalytic constant forminus-strand RNA synthesis
Background: Bamboo mosaic virus (BaMV) and the Potato virus X (PVX) are members of the genus Potexvirus andhave a single-stranded positive-sense RNA genome. The 3′-untranslated region (UTR) of the BaMV RNA genomewas mapped structurally into ABC (a cloverleaf-like), D (a stem-loop), and E (pseudoknot) domains. The BaMVreplicase complex that was isolated from the infected plants was able to recognize the 3′ UTR of PVX RNA toinitiate minus-strand RNA synthesis in vitro.Results: To investigate whether the 3′ UTR of PVX RNA is also compatible with BaMV replicase in vivo, weconstructed chimera mutants using a BaMV backbone containing the PVX 3′ UTR, which was inserted in or used toreplace the various domains in the 3′ UTR of BaMV. None of the mutants, except for the mutant with the PVX3′ UTR inserted upstream of the BaMV 3′ UTR, exhibited a detectable accumulation of viral RNA in Nicotianabenthamiana plants. The in vitro BaMV RdRp replication assay demonstrated that the RNA products were generatedby the short RNA transcripts, which were derived from the chimera mutants to various extents. Furthermore, theVmax/KM of the BaMV 3′ UTR (rABCDE) was approximately three fold higher than rABCP, rP, and rDE in minus-strandRNA synthesis. These mutants failed to accumulate viral products in protoplasts and plants, but were adequatelyreplicated in vitro.Conclusions: Among the various studied BaMV/PVX chimera mutants, the BaMV-S/PABCDE that containednon-interrupted BaMV 3′ UTR was the only mutant that exhibited a wild-type level of viral product accumulation inprotoplasts and plants. These results indicate that the continuity of the domains in the 3′ UTR of BaMV RNA wasnot interrupted and the domains were not replaced with the 3′ UTR of PVX RNA in vivo
Slipped Capital Femoral Epiphysis as a Complication of Growth Hormone Therapy
Slipped capital femoral epiphysis (SCFE) is a rare complication of growth hormone (GH) therapy. Here, we report three patients who developed SCFE during GH therapy. The first two patients had hypopituitarism and had started GH therapy at the age of 15 years 6 months and 13 years 9 months, respectively. SCFE developed 4 years and 1 year after GH therapy, respectively. The third patient had Prader-Willi syndrome with obesity and hypogonadism and began GH therapy at the age of 12 years and 11 months. SCFE developed 2 months after starting GH therapy. Pain over the hip joints or over the knees is an early sign of SCFE. Despite recommendation, none of the three patients continued GH therapy. A high index of suspicion during GH therapy in patients at high risk of SCFE is important for early diagnosis and appropriate management. [J Formos Med Assoc 2007;106(2 Suppl):S46-S50
New Graduate Nurses’ Clinical Competence, Clinical Stress, and Intention to Leave: A Longitudinal Study in Taiwan
This longitudinal research study aimed to develop a pregraduation clinical training program for nursing students before graduation and evaluate its effect on students’ self-perceived clinical competence, clinical stress, and intention to leave current job. A sample of 198 students returned the questionnaires before and after the program. They were followed up at 3, 6, and 12 months after graduation. Results showed that posttest clinical competence was significantly higher than pretest competence, positively related to clinical competence at 3 and 12 months, and negatively related to clinical stress at 3 months. The clinical competence at 3 months was positively related to clinical competence at 6 and 12 months, and clinical competence at 6 months was related to intention to leave at 12 months. Intention to leave at 6 months was positively related to intention to leave at 3 and 12 months. Clinical stress at 3 months was positively related to clinical stress at 6 and 12 months, but not related to intention to leave at any time points. The training program improved students’ clinical competence. The stressful time that was correlated with new graduate nurses’ intention to leave their job was between the sixth and twelfth months after employment
Inhibitory Effects of Terminalia catappa on UVB-Induced Photodamage in Fibroblast Cell Line
This study investigated whether Terminalia catappa L. hydrophilic extract (TCLW) prevents photoaging in human dermal fibroblasts after exposure to UVB radiation. TCLW exhibited DPPH free radical scavenging activity and protected erythrocytes against AAPH-induced hemolysis. In the gelatin digestion assay, the rates of collagenase inhibition by TCL methanol extract, TCLW, and its hydrolysates were greater than 100% at the concentration of 1 mg/mL. We found that serial dilutions of TCLW (10–500 μg/mL) inhibited collagenase activity in a dose-dependent manner (82.3% to 101.0%). However, TCLW did not significantly inhibit elastase activity. In addition, TCLW inhibited MMP-1 and MMP-9 protein expression at a concentration of 25 μg/mL and inhibited MMP-3 protein expression at a concentration of 50 μg/mL. TCLW also promoted the protein expression of type I procollagen. We also found that TCLW attenuated the expression of MMP-1, -3, and -9 by inhibiting the phosphorylation of ERK, JNK, and p38. These findings suggest that TCLW increases the production of type I procollagen by inhibiting the activity of MMP-1, -3 and -9, and, therefore, has potential use in anti-aging cosmetics
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