Signs, Symptoms, and Morphological Features of Idiopathic Condylar Resorption in Orthodontic Patients : A Survey-Based Study

Background: Idiopathic condylar resorption (ICR) is an aggressive degenerative disease of the temporomandibular joint that is most frequently observed in teenage girls. However, no specific cause of ICR has been identified. To explore the specific causes of the onset and progression of ICR, we performed a survey-based study on ICR in orthodontic patients and described its subjective symptoms, clinical signs, and condylar morphological features. Methods: A total of 1735 participants were recruited from 2193 orthodontic patients. For each participant, subjective symptoms and clinical signs of temporomandibular disorders (TMDs) were evaluated through clinical examination and a questionnaire. Furthermore, three-dimensional computed tomography (CT) was performed to diagnose ICR. Results: Among the 1735 patients evaluated, ICR was present in two male and ten female patients. All 12 patients had maxillary protrusion and an anterior open bite. Four patients with ICR underwent orthodontic treatment. Based on CT findings, patients with ICR had significantly different condylar sizes and shapes from patients with TMDs alone. Conclusions: The coexistence of intrinsic and extrinsic factors, such as sex-hormone imbalance and a history of orthodontic treatment, might lead to the onset of ICR. We suggest that growing patients suspected of having ICR should undergo CT evaluation because CT findings may precede clinical symptoms and signs

Sortase A-assisted metabolic enzyme ligation in Escherichia coli

We demonstrated the metabolic enzyme ligation by sortase A-mediated ligation (sortagging) for the redirection of metabolic flux thorough metabolic channeling. Staphylococcal sortase A (SrtA) is utilized for the ligation of metabolic enzymes. SrtA is transpeptidase, which recognizes Leu-Pro-Xaa-Thr-Gly sequences (LP tag) and cleaves between Thr and Gly, and subsequently links amino group of oligoglycine (G tag) thorough a native peptide bond. Sortagging enables to conjugate protein with other molecules in a site-specific manner. Minimal modifications of protein with short peptide tags; LP tag and G tag are only required for site-specific ligation. Hence, sortagging has been utilized for preparing a variety of bioconjugation not only in vitro but also in vivo.1 In current study, we hypothesize that SrtA-mediated metabolic enzyme ligation in cytoplasm of Escherichia coli facilitates processing metabolic intermediate, and redirects metabolic fluxes to desired pathway. As proof of concept, we constructed acetate producing E. coli with engineered endogenous metabolic pathway, which redirect central metabolic fluxes to acetate producing flux by the induction of chemical additives (Figure 1). The expression of SrtA was controlled by Lac operating promoter, metabolic channeling was videlicet occurred by the addition of IPTG. Acetyl-CoA was chosen as the intermediate model because acetyl-CoA is one of the most important central metabolic intermediates, which is converted to alcohols, fatty acids, and mevalonate derivatives. In this study, we tested covalent linking of pyruvate-formate lyase and phosphate acetyltransferase by sortase A-mediated ligation and evaluated the production of acetate. The time point of addition of IPTG was not critical for facilitating metabolic enzyme ligation, and acetate production increased upon expression of sortase A. These results show that sortase A-mediated enzyme ligation enhances an acetate-producing flux in E. coli. We have validated that sortase A-mediated enzyme ligation offers a metabolic channeling approach to redirect a central flux to a desired flux.2 Please click Additional Files below to see the full abstract

Metabolic engineering of S. pombe via CRISPR-Cas9 genome editing for lactic acid production from glucose and cellobiose

We constructed D-lactic acid (D-LA) producing Schizosaccharomyces pombe using CRISPR-Cas9 system. Two PDC genes, intact L-LDH, a minor gene of alcohol dehydrogenase (SPBC337.11) were disrupted to attenuate ethanol production pathway. To increase the cellular supply of acetyl-CoA, an important metabolite for growth, we introduced bacterial acetylating acetaldehyde dehydrogenase enzyme genes. Two kinds of acetaldehyde dehydrogenase genes from Escherichia coli, mhpF and eutE, were expressed. D-LA production was achieved by expressing D-lactate dehydrogenase gene from Lactobacillus plantarum. The engineered strains efficiently consumed glucose and produced 25.2 g/liter of D-LA from 35.5 g/liter of consumed glucose with the yield of 0.71 g-D-LA / g-glucose. Finally, we expressed beta-glucosidase by cell surface display techniques, and the resultant strain produced 24.4 g/L of D-LA from 30 g/L of cellobiose in minimal medium with the yield of 0.68 g-D-LA / g-glucose. This is the first report to generate metabolically engineered S. pombe strain using CRISPR-Cas9 system and we showed the possibility of S. pombe for the production host cell of value-added chemicals

Metabolic design of Escherichia coli for muconic acid production

Adipic acid(AA) is a versatile bulk chemical to be used for raw materials such as nylon 6,6. Currently, AA biosynthesis from bio-resources have received a lot of attention in recent years as environment-friendly and renewable AA production process. Muconic acid(MA), also known as 2,4-hexadienedioic acid, is expected as a biosynthesis precursor of AA. There are Several studies on MA biosynthesis using Escherichia coli introduced foreign genes. In those studies, MA is synthesized from intermediate products of shikimate pathway. However, the production volume is not sufficient and it is a hindrance to industrialization. In this study, we aimed to the high efficiency biosynthesis of MA using metabolic designed Escherichia coli. First, we designed the metabolism to increase the accumulation of phosphoenolpyruvic acid (PEP), which is one of the starting materials of the shikimate pathway. Next, we determined the optimal MA synthetic pathway branched from the shikimate pathway. Specifically, we examined three types of MA production pathway with PEP accumulation strain as parent and selected the pathway with the highest MA production. Finally, we examined efficient production of MA using fusion proteins. Shikimate pathway protein and MA production pathway protein were combined to direct carbon flux into MA production

Regional cerebral tissue blood flow measured by the colored microsphere method during retrograde cerebral perfusion

AbstractBrain tissue blood flow was measured precisely by the colored microsphere method during retrograde cerebral perfusion in 10 normothermic mongrel dogs. The average tissue blood flow rates to the cerebral cortex, cerebral medulla, brain stem, cerebellum, and spinal cord during retrograde cerebral perfusion at 25 mm Hg of external jugular venous pressure were 10.5 ± 10.3, 4.2 ± 4.6, 11.1 ± 9.8, 12.3 ± 8.6, and 9.1 ± 5.8 ml/min per 100 gm, respectively. The brain was perfused wholly by retrograde cerebral perfusion without lateralization. Total cerebral blood flow was calculated as the sum total rates of blood flow to each area. Total cerebral blood flow during retrograde cerebral perfusion at 25 mm Hg was 7.8 ± 4.4 ml/min, which represented 3.5% ± 1.9% of whole body blood flow and one third of the total cerebral blood flow (28.0 ± 4.2 ml/min) during cardiopulmonary bypass at a flow rate of 1000 ml/min. Oxygen consumption and carbon dioxide elimination by the total cerebrum during retrograde cerebral perfusion at 25 mm Hg were 0.54 ± 0.23 ml/min and 34 ± 15 μmol/min, respectively, or 8.6% ± 3.6% and 7.0% ± 3.1% of the corresponding whole body value and represented about one third of that measured during cardiopulmonary bypass (1.21 ± 0.39 ml/min and 96 ± 15 μmol/min). Total cerebral blood flow, total cerebral oxygen consumption, and carbon dioxide elimination increased as the external jugular venous pressure increased from 15 to 25 mm Hg; however, no further increase occurred once the external jugular venous pressure exceeded 25 mm Hg. (J THORAC CARDIOVASC SURG 1995;109:772-9

Persistent Synapse Loss Induced by Repetitive LTD in Developing Rat Hippocampal Neurons

Synaptic pruning is a physiological event that eliminates excessive or inappropriate synapses to form proper synaptic connections during development of neurons. Appropriate synaptic pruning is required for normal neural development. However, the mechanism of synaptic pruning is not fully understood. Strength of synaptic activity under competitive circumstances is thought to act as a selective force for synaptic pruning. Long-term depression (LTD) is a synaptic plasticity showing persistent decreased synaptic efficacy, which is accompanied by morphological changes of dendritic spines including transient retraction. Repetitive induction of LTD has been shown to cause persistent loss of synapses in mature neurons. Here, we show that multiple, but not single, induction of LTD caused a persistent reduction in the number of dendritic synapses in cultured rat developing hippocampal neurons. When LTD was induced in 14 days in vitro cultures by application of (RS)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor (mGluR) agonist, and repeated three times with a one day interval, there was a significant decrease in the number of dendritic synapses. This effect continued up to at least two weeks after the triple LTD induction. The persistent reduction in synapse number occurred in the proximal dendrites, but not the distal dendrites, and was prevented by simultaneous application of the group I/II mGluR antagonist (S)-a-methyl-4-carboxyphenylglycine (MCPG). In conclusion, we found that repetitive LTD induction in developing neurons elicits synaptic pruning and contributes to activity-dependent regulation of synapse number in rat hippocampal neurons

Direct ethanol production from cellulosic materials using a diploid strain of Saccharomyces cerevisiae with optimized cellulase expression

<p>Abstract</p> <p>Background</p> <p>Hydrolysis of cellulose requires the action of the cellulolytic enzymes endoglucanase, cellobiohydrolase and β-glucosidase. The expression ratios and synergetic effects of these enzymes significantly influence the extent and specific rate of cellulose degradation. In this study, using our previously developed method to optimize cellulase-expression levels in yeast, we constructed a diploid <it>Saccharomyces cerevisiae </it>strain optimized for expression of cellulolytic enzymes, and attempted to improve the cellulose-degradation activity and enable direct ethanol production from rice straw, one of the most abundant sources of lignocellulosic biomass.</p> <p>Results</p> <p>The engineered diploid strain, which contained multiple copies of three cellulase genes integrated into its genome, was precultured in molasses medium (381.4 mU/g wet cell), and displayed approximately six-fold higher phosphoric acid swollen cellulose (PASC) degradation activity than the parent haploid strain (63.5 mU/g wet cell). When used to ferment PASC, the diploid strain produced 7.6 g/l ethanol in 72 hours, with an ethanol yield that achieved 75% of the theoretical value, and also produced 7.5 g/l ethanol from pretreated rice straw in 72 hours.</p> <p>Conclusions</p> <p>We have developed diploid yeast strain optimized for expression of cellulolytic enzymes, which is capable of directly fermenting from cellulosic materials. Although this is a proof-of-concept study, it is to our knowledge, the first report of ethanol production from agricultural waste biomass using cellulolytic enzyme-expressing yeast without the addition of exogenous enzymes. Our results suggest that combining multigene expression optimization and diploidization in yeast is a promising approach for enhancing ethanol production from various types of lignocellulosic biomass.</p