Enhanced production of laccase in Trametes vesicolor by the addition of ethanol

In a medium containing 40 g ethanol l^–1, laccase production by Trametes versicolor was 2.6 unit per ml of the supernatant, which was over 20 times higher than that without ethanol. Laccase activity with ethanol was quite comparable to that with the well-known inducers such as veratryl alcohol, xylidine and guaiacol. With other white-rot fungi, Coriolus hirsutus and Grifola frondosa, ethanol had a similar stimulatory effect on laccase production.     

Biosynthesis of yeast mannan. Characterization of mannan-synthesizing enzyme systems from mutants defective in mannan structure

The yeastSaccharomyces cerevisiae X2180-1A (wild) and its mutants X2180-1A-4 (mnn 1) and X2180-1A-5 (mnn 2) defective in mannan biosynthesis were used as enzyme sources to catalyzein vitro mannosyl transfer from GDP-[¹⁴C-U]-mannose to endogenous glycoproteins as well as to exogenous, low-molecular weight acceptors. While the enzyme preparation from the wild strain exhibited all mannosyl transferase activities involved in mannan biosynthesis by catalyzing the synthesis of characteristic mannoprotein, the enzyme frommnn 1 mutant failed to catalyze the synthesis of α(1→3) mannoside linkages both with endogenous as well as with exogenous acceptors. The enzyme preparation from themnn 2 mutant catalyzed the formation of mannoprotein very similar to that obtained with the enzyme from the wild strain. The most important difference was the formation of a higher number of unsubstituted mannosyl units in the α(1→ 6) linked mannan backbone. The observed results support the hypothesis that in themnn 1 the mutation has altered the structural gene involved in biosynthesis of an α(1→3) mannosyl transferase catalyzing the addition of α(1→3) linked mannosyl units to α(1→2) linked mannotrioses in the polysaccharide side chains and in the oligosaccharides attached to serine and/or threonine in the protein part of mannan molecule. Themnn 2 mutant represents most probably a kind of regulatory mutation where the activity of an α(1→2) mannosyl transferase adding the mannosyl units directly to α(1→6) linked backbone in the outer region of polysacoharide part of yeast mannan is repressedin vivo but becomes significantin vitro.     

Formation of the death domain complex between FADD and RIP1 proteins in vitro

Fas-associated death domain (FADD) protein is an adapter molecule that bridges the interactions between membrane death receptors and initiator caspases. The death receptors contain an intracellular death domain (DD) which is essential to the transduction of the apoptotic signal. The kinase receptor-interacting protein 1 (RIP1) is crucial to programmed necrosis. The cell type interplay between FADD and RIP1, which mediates both necrosis and NF-κB activation, has been evaluated in other studies, but the mechanism of the interaction of the FADD and RIP1 proteins remain poorly understood. Here, we provided evidence indicating that the DD of human FADD binds to the DD of RIP1 in vitro. We developed a molecular docking model using homology modeling based on the structures of FADD and RIP1. In addition, we found that two structure-based mutants (G109A and R114A) of the FADD DD were able to bind to the RIP1 DD, and two mutations (Q169A and N171A) of FADD DD and four mutations (G595, K596, E620, and D622) of RIP1 DD disrupted the FADD–RIP1 interaction. Six mutations (Q169A, N171A, G595, K596, E620, and D622) lowered the stability of the FADD–RIP1 complex and induced aggregation that structurally destabilized the complex, thus disrupting the interaction.     

Gender Difference in the Epidemiological Association between Metabolic Syndrome and Olfactory Dysfunction: The Korea National Health and Nutrition Examination Survey

Metabolic syndrome (MetS) is associated with a higher risk of morbidity and/or mortality for various chronic diseases. The aim of this study was to investigate the relationships of MetS and its components with olfactory dysfunction in a representative Korean population. We analyzed the data from the Korean National Health and Nutrition Examination Survey (2008–2010). A total of 11,609 adults who underwent otolaryngological examination were evaluated. The olfactory function was classified as normosmia or hyposmia by a self-report questionnaire according to the sense problems of smell during the past 3 months. MetS was diagnosed if a participant had at least three of the following: (1) WC ≥90 cm in men and ≥80 cm in women; (2) fasting blood sugar ≥ 100 mg/dL or medication use for elevated glucose; (3) fasting triglyceride ≥ 150 mg/dL or cholesterol-lowering medication use; (4) HDL-cholesterol <40 mg/dL in men and <50 mg/dL in women or cholesterol-lowering medication use; and (5) SBP ≥ 130 mmHg and/or DBP ≥ 85 mmHg or antihypertensive drug use for patients with a history of hypertension. The prevalence of olfactory dysfunction in the study population was 6.3%. The prevalence of olfactory dysfunction was significantly higher in older people with MetS than in those without MetS in both sexes (male, 42.0 ± 3.4% vs. 34.7 ± 0.9%, p = 0.0354; female, 46.2 ± 2.8% vs. 37.8 ± 0.8%, p = 0.0026). However, elevated waist circumference, elevated fasting glucose, elevated triglycerides, reduced HDL cholesterol, elevated blood pressure, severe stress, depressed mood, and suicidal ideation were significantly associated with olfactory dysfunction only in women. After controlling for confounders, olfactory dysfunction was significantly associated with MetS (odds ratio, 1.352; 95% confidence interval, 1.005–1.820) only in women. MetS are associated with olfactory dysfunction only in Korean women.     

10 mAh cm−2 Cathode by Roll-to-Roll Process for Low Cost and High Energy Density Li-Ion Batteries

Roll-to-roll dry processing enables the manufacture of high energy density and low cost Li-ion batteries (LIBs). However, as the thickness of the electrode fabricated by dry processing becomes greater (≥10 mAh cm⁻²), Li-ion migration resistance (R_ion) and charge-transfer resistance (R_ct) in the electrode dramatically increase due to long diffusion lengths for Li-ion and electron. Therefore, it is important to reduce diffusion lengths in the electrode to achieve high energy density LIBs. The dry electrode with a high areal capacity of 10 mAh cm⁻² and low resistance can be achieved by following three characteristics. First, the fibrillization behavior of polytetrafluoroethylene (PTFE) binder is controlled by adjusting the processing temperature during the fibrillization process, which enables uniform distribution of PTFE binder and carbon black (CB). Second, pore size/distribution and conducting network are engineered by multi-dimensional conducting agents, enhancing Li-ions and electrons transport in the electrode. Finally, the structural integrity of LiNi_0.80Co_0.15Al_0.05O₂ (NCA) particles is improved without fractures, which enables uniform pore distribution in the electrode by controlling the calendering step. The prepared 10 mAh cm⁻² dry electrode with homogeneous microstructure shows reduced R_ion and R_ct due to short diffusion lengths, which improves electrochemical performances in LIBs with a high volumetric energy density of ≈710 Wh L⁻¹.     

Adaptor protein containing PH domain, PTB domain and leucine zipper (APPL1) regulates the protein level of EGFR by modulating its trafficking

The EGFR-mediated signaling pathway regulates multiple biological processes such as cell proliferation, survival and differentiation. Previously APPL1 (adaptor protein containing PH domain, PTB domain and leucine zipper 1) has been reported to function as a downstream effector of EGF-initiated signaling. Here we demonstrate that APPL1 regulates EGFR protein levels in response to EGF stimulation. Overexpression of APPL1 enhances EGFR stabilization while APPL1 depletion by siRNA reduces EGFR protein levels. APPL1 depletion accelerates EGFR internalization and movement of EGF/EGFR from cell surface to the perinuclear region in response to EGF treatment. Conversely, overexpression of APPL1 decelerates EGFR internalization and translocation of EGF/EGFR to the perinuclear region. Furthermore, APPL1 depletion enhances the activity of Rab5 which is involved in internalization and trafficking of EGFR and inhibition of Rab5 in APPL1-depleted cells restored EGFR levels. Consistently, APPL1 depletion reduced activation of Akt, the downstream signaling effector of EGFR and this is restored by inhibition of Rab5. These findings suggest that APPL1 is required for EGFR signaling by regulation of EGFR stabilities through inhibition of Rab5.     

Ionizing radiation-inducible microRNA miR-193a-3p induces apoptosis by directly targeting Mcl-1

The functions of microRNAs (miRNAs) as either oncogenes or tumor suppressors in regulating cancer-related events have been established. We analyzed the alterations in the miRNA expression profile of the glioma cell line U-251 caused by ionizing radiation (IR) by using an miRNA array and identified several miRNAs whose expression was significantly affected by IR. Among the IR-responsive miRNAs, we further examined the function of miR-193a-3p, which exhibited the most significant growth-inhibiting effect. miR-193a-3p was observed to induce apoptosis in both U-251 and HeLa cells. We also demonstrated that miR-193a-3p induces the accumulation of intracellular reactive oxygen species (ROS) and DNA damage as determined by the level of γH2AX and by performing the comet assay. The induction of both apoptosis and DNA damage by miR-193a-3p was blocked by antioxidant treatment, indicating the crucial role of ROS in the action of miR-193a-3p. Among the putative target proteins, the expression of Mcl-1, an anti-apoptotic Bcl-2 family member, decreased because of miR-193a-3p transfection. A reporter assay using a luciferase construct containing the 3′-untranslated region of Mcl-1 confirmed that Mcl-1 is a direct target of miR-193a-3p. Down-regulation of Mcl-1 by siRNA transfection closely mimicked the outcome of miR-193a-3p transfection showing increased ROS, DNA damage, cytochrome c release, and apoptosis. Ectopic expression of Mcl-1 suppressed the pro-apoptotic action of miR-193a-3p, suggesting that Mcl-1 depletion is critical for miR-193a-3p induced apoptosis. Collectively, our results suggest a novel function for miR-193a-3p and its potential application in cancer therapy.     

Enhancement of extracellular glucose oxidase production in pH-stat feed-back controlled fed-batch culture of recombinant Saccharomyces cerevisiae

Glucose oxidase (GOD) from Aspergillus niger was expressed in Saccharomyces cerevisiae under the regime of GAL-10 promoter and GAL-7 terminator of S. cerevisiae and -amylase signal sequence of Aspergillus oryzae. The enhancement of the expression level was achieved in pH-stat feed-back controlled fed-batch culture. The highest titre of extracellular GOD was 199 U/ml which marked two fold improvement over the batch (95 U/ml) and 28% above that of non-feed back controlled fed-batch (154 U/ml) operation. © Rapid Science Ltd. 1998     

Death domain complex of the TNFR-1, TRADD,and RIP1 proteins for death-inducing signaling

Apoptosis can be induced by an extrinsic pathway involving the ligand-mediated activation of death receptors such as tumor necrosis factor receptor-1 (TNFR-1). TNFR-1-associated death domain (TRADD) protein is an adapter molecule that bridges the interaction between TNFR-1 and receptor-interacting serine/threonine-protein kinase 1 (RIP1). However, the molecular mechanism of the complex formation of these proteins has not yet been identified. Here, the binding among TNFR-1, TRADD, and RIP1 was identified using a GST pull-down assay and Biacore biosensor experiment. This study showed that structural characterization and formation of the death-signaling complex could be predicted using TNFR-1, TRADD, and RIP1. In addition, we found that the structure-based mutations of TNFR-1 (P367A and P368A), TRADD (F266A), and RIP1 (M637A and R638A) disrupted formation of the death domain (DD) complex and prevented stable interactions among those DDs.