SHMT2 drives glioma cell survival in ischaemia but imposes a dependence on glycine clearance.

Cancer cells adapt their metabolic processes to support rapid proliferation, but less is known about how cancer cells alter metabolism to promote cell survival in a poorly vascularized tumour microenvironment. Here we identify a key role for serine and glycine metabolism in the survival of brain cancer cells within the ischaemic zones of gliomas. In human glioblastoma multiforme, mitochondrial serine hydroxymethyltransferase (SHMT2) and glycine decarboxylase (GLDC) are highly expressed in the pseudopalisading cells that surround necrotic foci. We find that SHMT2 activity limits that of pyruvate kinase (PKM2) and reduces oxygen consumption, eliciting a metabolic state that confers a profound survival advantage to cells in poorly vascularized tumour regions. GLDC inhibition impairs cells with high SHMT2 levels as the excess glycine not metabolized by GLDC can be converted to the toxic molecules aminoacetone and methylglyoxal. Thus, SHMT2 is required for cancer cells to adapt to the tumour environment, but also renders these cells sensitive to glycine cleavage system inhibition.

Effects of dopaminergic depletion and brain atrophy on neuropsychiatric symptoms in de novo Parkinson's disease.

BACKGROUND: Neuropsychiatric symptoms impact the patients' quality of life and caregivers' burdens in Parkinson's disease (PD). We aimed to investigate the effects of striatal dopaminergic depletion and brain atrophy on the neuropsychiatric symptoms of patients with PD. METHODS: Two hundred and seven patients with de novo drug-naïve PD underwent dopamine transporter (DAT) positron emission tomography and brain MRI scanning. In addition, the patients were assessed with caregiver-administered neuropsychiatric inventory (NPI) questionnaires. To evaluate the effects of DAT uptake, subcortical volume and cortical thinning on the patients' neuropsychiatric symptoms, we performed logistic regression and negative binomial regression analyses on the NPI data after controlling for possible confounders. RESULTS: Frontal cortical thinning was associated with the presence of nighttime behaviour and irritability, and the thinning correlated with the severity of the nighttime behaviour. Temporal cortical thinning was associated with the presence of aggression/agitation, and it correlated with the severity of the aggression/agitation. Subcortical atrophy in the accumbens was associated with the presence of disinhibition and correlated with the severity of the disinhibition. Putamen atrophy and insular thinning were independently associated with the presence of apathy, but only insular thinning correlated with the severity of the apathy. Of the predictors, only frontal cortical thinning correlated with the total NPI score. CONCLUSIONS: The results of this study suggested that accumbens atrophy and frontotemporal cortical thinning, especially frontal cortical thinning, independently contributed to neuropsychiatric symptoms in patients with PD, while DAT uptake did not affect the neuropsychiatric symptoms.

Preoperative nomogram for prediction of microscopic parametrial infiltration in patients with FIGO stage IB cervical cancer treated with radical hysterectomy.

OBJECTIVE: This study aimed to establish a nomogram to predict microscopic parametrial infiltration (PMI) by combining preoperative clinicopathologic factors in FIGO stage IB cervical cancer patients treated by radical hysterectomy (RH). METHODS: We retrospectively analyzed clinicopathologic data of 298 patients with FIGO stage IB cervical cancer treated by RH between February 2000 and March 2015. The nomogram was developed based on multivariate logistic regression analysis of preoperative clinicopathologic data. The accuracy and discriminative ability of the nomogram were evaluated by a concordance index and calibration curve. The low-risk group was predefined as having a predicted probability of PMI <10%. RESULTS: Multivariate analysis identified diameter-based tumor volume and disruption of the cervical stromal ring on magnetic resonance imaging, serum squamous cell carcinoma antigen level, and menopausal status as independent prognostic factors associated with PMI. The concordance index of the nomogram was 0.940 (95% CI, 0.908-0.967), and calibration plots revealed good agreement between the observed probabilities and nomogram-predicted probabilities (Hosmer Lemeshow test, p=0.574). The nomogram classified 200 out of 298 patients (67.1%) as low risk. In the low-risk group, the predicted probability of PMI was 3.5% and the actual PMI rate was 2.5% (5 out of 200). CONCLUSIONS: We developed a preoperative nomogram predicting microscopic PMI in surgically treated FIGO stage IB cervical cancer patients. The probabilities derived from this nomogram may have the potential to provide valuable guidance for physicians regarding the primary management of FIGO stage IB cervical cancer patients.

Effect of crude glycerol-derived inhibitors on ethanol production by Enterobacter aerogenes.

In this study, ethanol production from pure and crude glycerol using Enterobacter aerogenes ATCC 29007 was evaluated under anaerobic culture conditions. Inhibitory effects of substrate concentrations, pH, and salt concentrations were investigated based on crude glycerol components. Ethanol production was performed with pure glycerol concentrations ranging from 5 to 30 g/L to evaluate the effects of substrate concentration and osmotic pressure. The consumed glycerol was 5-14.33 g/L, and the yield of ethanol was higher than 0.75 mol ethanol/mol glycerol after 24 h of cultivation. To evaluate the inhibitory effects of salts (NaCl and KCl), experiments were performed with 0-20 g/L of each salt. Inhibitory effects of salts were strongest at high salt concentrations. The inhibitory effect of pH was performed in the pH range 4-10, and cell growth and ethanol production were highest at pH 5-6. Also, ethanol production was slightly inhibited at low concentration of crude glycerol comparison with pure glycerol. However, significant inhibitory effects were not observed at 1.5 and 2% crude glycerol which showed higher ethanol production compared to pure glycerol.

Optimization of the process for biodiesel production using a mixture of immobilized Rhizopus oryzae and Candida rugosa lipases.

In this study, the enzymatic process for biodiesel production was optimized using a mixture of immobilized Rhizopus oryzae and Candida rugosa lipases. The optimal temperature and agitation speed for biodiesel production were 45oC and 300 rpm, respectively. The optimal ratio of R. oryzae and C. rugosa lipases in the mixture was 3:1 (w:w). When 3mmol of methanol was the initial reaction medium and 3mmol of methanol was added every 1.5 h during biodiesel production, biodiesel conversion was over 98% at 4 h. In addition, when the immobilized lipase mixture was reused, biodiesel conversion exceeded 80% after 5 reuses.

Fatty acids reduce the tensile strength of fungal hyphae during cephalosporin C production in Acremonium chrysogenum.

Fragmentation rate constants, which can be used to estimate the tensile strength of fungal hyphae, were used to elucidate relationships between morphological changes and addition of fatty acids during cephalosporin C production in Acremonium chrysogenum M35. The number of arthrospores increased gradually during fermentation, and, in particular, was higher in the presence of rice oil, oleic acid or linoleic acid than in their absence. Because supplementation of rice oil or fatty acids increased cephalosporin C, we concluded that differentiation to arthrospores is related to cephalosporin C production. To estimate the relative tensile strengths of fungal hyphae, fragmentation rate constants (k (frag)) were measured. When rice oil, oleic acid, or linoleic acid were added into medium, fragmentation rate constants were higher than for the control, and hyphal tensile strengths reduced. The relative tensile strength of fungal hyphae, however was not constant presumably due to differences in physiological state.

The within-host population dynamics of normal flora in the presence of an invading pathogen and antibiotic treatments.

A mathematical competition model between normal flora and an invading pathogen was devised to allow analysis of bacterial infections in a host. The normal flora includes the various microorganisms that live on or within the host and act as a primary human immune system. Despite the important role of the normal flora, no mathematical study has been undertaken on models of the interaction between it and invading pathogens against a background of antibiotic treatment. To quantify key elements of bacterial behavior in a host, pairs of nonlinear differential equations were used to describe three categories of human health conditions, namely, healthy, latent infection, and active infection. In addition, a cutoff value was proposed to represent the minimum population level required for survival. The recovery of normal flora after antibiotic treatment was also included in the simulation because of its relation to human health recovery. The significance of each simulation parameter for the bacterial growth model was investigated. The devised simulation showed that bacterial proliferation rate, carrying capacity, initial population levels, and competition intensity have a significant effect on bacterial behavior. Consequently, a model was established to describe competition between normal flora and an infiltrating pathogen. Unlike other population models, the recovery process described by the devised model can describe the human health recovery mechanism.

Optimization of culture medium for lactosucrose ( G-beta-D-galactosylsucrose) Production by Sterigmatomyces elviae mutant using statistical analysis.

In this study, the optimization of culture medium using a Sterigmatomyces elviae mutant was investigated using statistical analysis to increase the cell mass and lactosucrose ((4)G-beta-D-galactosylsucrose) production. In basal medium, the cell mass and lactosucrose production were 4.12 g/l and 140.91 g/l, respectively. However, because of the low cell mass and lactosucrose production, optimization of culture medium was carried out to increase the cell mass and lactosucrose production. Culture media were optimized by the S. elviae mutant using analysis of variance (ANOVA) and response surface methodology (RSM). Central composite designs using RSM were utilized in this investigation. Quadratic models were obtained for cell mass and lactosucrose production. In the case of cell mass, optimal components of the medium were as follows: sucrose 1.13%, yeast extract 0.99%, bactopeptone 2.96%, and ammonium sulfate 0.40%. The predicted maximum value of cell mass was about 5.20 g/l and its experimental value was 5.08 g/l. In the case of lactosucrose production, optimal components of the medium were as follows: sucrose 0.96%, yeast extract 1.2%, bactopeptone 3.0%, and ammonium sulfate 0.48%. Then, the predicted maximum value of lactosucrose production was about 194.12 g/l and the corresponding experimental value was about 183.78 g/l. Therefore, by culturing using predicted conditions, the real cell mass and lactosucrose production increased to 23.3% and 30.42%, respectively.

Continuous production of lactosucrose by immobilized Sterigmatomyces elviae mutant.

In this study, in order to develop a continuous production process of lactosucrose in a packed-bed reactor, Sterigmatomyces elviae ATCC 18894 was selected and mutated. The mutant strain of S. elviae showed 54.3% higher lactosucrose production than the wild type. Reaction conditions such as temperature, pH, substrate concentration and flow rate were also optimized. Under optimized reaction conditions (50 degrees C, pH 6.0, 25% sucrose and 25% lactose as substrate, flow rate 1.2 ml/min), the maximum concentration of lactosucrose (192 g/l) was obtained. In a packed-bed reactor, continuous production of lactosucrose was performed using S. elviae mutant immobilized in calcium alginate, and about 180 g/l of lactosucrose production was achieved for 48 days.

Pretreatment of lipase with soybean oil before immobilization to prevent loss of activity.

Lipase was pretreated with soybean oil in order to allow fatty acids to bond to the active site before immobilization. This pretreated lipase exhibited steric hindrance around the active site such that during immobilization, covalent bonds were formed between the carrier and the lipase region far from the active site. The activity of the pretreated lipase immobilized covalently on a silica gel was 530 U/g-matrix, which is 16 times higher than that of the immobilized non-pretreated lipase. In addition, the immobilized lipase activity was maintained at levels exceeding 90% of its original activity after 10 reuses.

Learning curve analysis of laparoscopic radical hysterectomy for gynecologic oncologists without open counterpart experience.

OBJECTIVE: To evaluate the learning curve of laparoscopic radical hysterectomy (LRH) for gynecologic oncologists who underwent residency- and fellowship-training on laparoscopic surgery without previous experience in performing abdominal radical hysterectomy (ARH). METHODS: We retrospectively reviewed 84 patients with FIGO (International Federation of Gynecology and Obstetrics) stage IB cervical cancer who underwent LRH (Piver type III) between April 2006 and March 2014. The patients were divided into two groups (surgeon A group, 42 patients; surgeon B group, 42 patients) according to the surgeon with or without ARH experience. Clinico-pathologic data were analyzed between the 2 groups. Operating times were analyzed using the cumulative sum technique. RESULTS: The operating time in surgeon A started at 5 to 10 standard deviations of mean operating time and afterward steeply decreased with operative experience (Pearson correlation coefficient=-0.508, P=0.001). Surgeon B, however, showed a gentle slope of learning curve within 2 standard deviations of mean operating time (Pearson correlation coefficient=-0.225, P=0.152). Approximately 18 cases for both surgeons were required to achieve surgical proficiency for LRH. Multivariate analysis showed that tumor size (>4 cm) was significantly associated with increased operating time (P=0.027; odds ratio, 4.667; 95% confidence interval, 1.187 to 18.352). CONCLUSION: After completing the residency- and fellowship-training course on gynecologic laparoscopy, gynecologic oncologists, even without ARH experience, might reach an acceptable level of surgical proficiency in LRH after approximately 20 cases and showed a gentle slope of learning curve, taking less effort to initially perform LRH.

A biodegradable polymersome with pH-tuning on-off membrane based on poly(ß-amino ester) for drug delivery.

A nanoscale biodegradable polymersome with pH-tuning on-off membrane is prepared via the self-assembly of poly(ß-amino ester)-based amphiphilic copolymers. The pH-sensitive polymersome-like vesicle structure includes two layers that can encapsulate either hydrophobic or hydrophilic therapeutic drugs at physiological pH 7.4. Below a pH of 7.0, the polymersome membrane forms tunnels through which the drug cargo can be rapidly released. The size and morphology of the polymersome are measured by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The pH sensitivity is confirmed by fluorescence spectroscopy. The pH-sensitive drug-delivery polymersome provides a simple and powerful smart carrier for the delivery and controlled release of drugs.

Synthesis and evaluation of biotin-conjugated pH-responsive polymeric micelles as drug carriers.

pH-Responsive polymeric micelles have been investigated as drug carriers for chemotherapy. Ligand-mediated polymeric micelles, which can penetrate the target tumors due to their high binding affinity to a specific receptor on the surface of tumors, were developed to achieve targeted drug delivery. In this study, biotin-conjugated methoxypoly(ethylene glycol)-grafted-poly(ß-amino ester) was prepared for active and pH-sensitive tumor targeting. These polymers were modified by cholesteryl chloroformate to improve the hydrophobicity of the micelle core. The structure of the biotin-conjugated polymer was confirmed by (1)H NMR spectroscopy, and the existence of biotin at the surface of the polymeric micelles was evaluated by an 4'-hydroxyazobenzene-2-carboxylic acid/avidin (HABA/avidin) binding assay at different pHs. The micelle properties were determined by dynamic light scattering and the result showed that the mean size of the polymeric micelles was approximately 20 nm. For cancer therapy, doxorubicin (DOX) was loaded into the polymeric micelles with a high loading efficiency. From the in vitro cellular uptake results, the biotin-conjugated polymeric micelles can effectively release doxorubicin at acidic tumor cells compared to the micelles without biotin. Overall, biotin-conjugated pH-responsive polymeric micelles have great potential to be used as drug carriers.

Evaluation of pH-sensitive poly(ß-amino ester)-graft-poly(ethylene glycol) and its usefulness as a pH-sensor and protein carrier.

In this study, some possible biomedical applications of a pH-sensitive and amphiphilic copolymer as a pH sensor and protein delivery system are reported. PAE-g-PEG was used as a pH-sensitive polymer that can exhibit a sharp pH-dependent transition. Various fluorescent dyes including pyrene and RITC can be used to label the pH-sensitive polymer PAE-g-PEG, which was evaluated for protein encapsulation. pH-sensing was possible by observing excimer formation of the labeled pyrene via pH-dependent expansion of the polymeric chain. Also, it was confirmed that FITC-BSA could be entrapped in RITC-labeled pH-sensitive micelles of PAE-g-PEG by FRET. As a result, PAE-g-PEG can be a pH sensor and carrier for protein delivery.

Improvement of electrical properties via glucose oxidase-immobilization by actively turning over glucose for an enzyme-based biofuel cell modified with DNA-wrapped single walled nanotubes.

One of the major areas of study associated with enzyme fuel cells (EFCs) has been identification of redox enzymes with high electron transfer rates that lead to a high power output. The effects of a method of enzyme immobilization by actively turning over glucose on the electrical properties of a fuel cell were evaluated under ambient conditions in attempt to increase the power of an EFC modified with DNA-wrapped single walled carbon nanotubes (SWNTs). The anode cyclic voltammetry (CV cycle) electrical properties increased as a result of glucose oxidase (GOD) immobilization by actively turning over glucose. Furthermore, an EFC that employed DNA-wrapped SWNTs and GOD immobilization in conjunction with protection of the active site increased the stability of the cell, which enabled maintenance of a high level of power production (ca. 730-760 µW cm(-2)) for 1 week.

Biodiesel production by a mixture of Candida rugosa and Rhizopus oryzae lipases using a supercritical carbon dioxide process.

In this study, various factors, such as temperature, pressure, agitation speed, water content, and the concentration and ratio of immobilized ROL and CRL were investigated for the efficient enzymatic production of biodiesel using a supercritical carbon dioxide process. Furthermore, a stepwise reaction method for the maintenance of immobilized lipase activity was optimized. Optimal conditions for biodiesel production were determined to be as follows: 130 bar pressure, 45 °C temperature, 250 rpm agitation speed, 10% water content, and 20% immobilized ROL and CRL (1:1). When batch process was performed under optimal conditions, the biodiesel conversion yield was 99.13% at 3 h. Biodiesel conversion yield was 99.99% at 2 h when 90 mmol methanol was used in a stepwise reaction. Moreover, the conversion yield of biodiesel produced by the repeated recycling of immobilized lipase in the stepwise reactions was 85% after 20 reuses.

Pretreatment of rice straw by proton beam irradiation for efficient enzyme digestibility.

Biomass was pretreated with proton beam irradiation (PBI) in order to enhance enzyme digestibility. Rice straw and soaking in aqueous ammonia (SAA)-treated rice straw were treated with 1-25 kGy doses of PBI at a beam energy of 45 MeV. The optimal doses of PBI for efficient sugar recovery were 15 and 3 kGy for rice straw and SAA-treated rice straw, respectively. When PBI was applied to rice straw at 15 kGy, the glucose conversion reached 68% of the theoretical maximum at 72 h. When 3 kGy of PBI was applied to SAA-treated rice straw, approximately 90% of the theoretical glucose conversion was obtained at 12 h compared to a 89% conversion at 48 h. After 2 h of enzymatic saccharification, the initial reaction rates of raw rice straw pretreated with 15 kGy of PBI and SAA-treated rice straw pretreated with 3 kGy of PBI were 1.4 × 10⁻4 and 9.7 × 10⁻4 g L⁻¹ s⁻¹, respectively. Further, the results of X-ray diffractometry support the effect of PBI on sugar recovery, whereas scanning electron microscopy images revealed a more rugged rice straw surface.

Application of an enzyme-based biofuel cell containing a bioelectrode modified with deoxyribonucleic acid-wrapped single-walled carbon nanotubes to serum.

Enzyme-based biofuel cells (EFCs) are a form of biofuel cells (BFCs) that can utilize redox enzymes as biocatalysts. Applications of an EFC to an implantable system are evaluated under mild conditions, such as ambient temperature or neutral pH. In the present study, an EFC containing a bioelectrode modified with deoxyribonucleic acid (DNA)-wrapped single-walled carbon nanotubes (SWNTs) was applied to a serum system. The protection of immobilized glucose oxidase (GOD) using DNA-wrapped SWNTs was investigated in a trypsin environment, which can exist in a serum. GOD is immobilized by masking the active site onto the anode electrode. The anode/cathode system in the cell was composed of GOD/laccase as the biocatalysts and glucose/oxygen as the substrates in serum. The electrical properties of the anode in serum according to cyclic voltammetry (CV cycle) were improved using the DNA-wrapped SWNTs. Overall, an EFC that employed DNA-wrapped SWNTs and GOD immobilization in conjunction with protection of the active site increased the stability of GOD in serum, which enabled a high level of power production (ca. 190 µW/cm(2)) for up to 1 week.

Verticillium lecanii spore formulation using UV protectant and wetting agent and the biocontrol of cotton aphids.

Verticillium lecanii spores (10(8 )spores ml(-1)) suspended in 1% (w/v) montmorillonite SCPX-1374 and 1% (w/v) of the wetting agent, EM-APW#2, which is a polyoxyethylene, had approx. 80% survival after exposure to UV-C for 30 min and about 93% after exposure to UV-B for 6 h. In greenhouse testing, cotton aphid densities increased 14-fold over their initial density in 15 d without spore application. However, initial cotton aphid densities were decreased by 60% of the initial level when plants were treated with the spore formulation.

High-level production of astaxanthin by Xanthophyllomyces dendrorhous mutant JH1 using statistical experimental designs.

Medium composition was optimized for high-level production of astaxanthin by Xanthophyllomyces dendrorhous mutant JH1 using statistical experimental designs. Glucose and yeast extract were the most important factors affecting astaxanthin production. Glucose 3.89%, yeast extract 0.29%, KH2PO4 0.25%, MgSO4 0.05%, MnSO4 0.02%, and CaCl2 0.01% were optimum for high-level production of astaxanthin. Under optimized conditions, the maximum concentration of astaxanthin obtained after 7 d of cultivation was 36.06 mg/l. The concentration of astaxanthin predicted by a polynomial model was 36.16 mg/l.