T cell antigen receptor-mediated activation of the Ras/mitogen-activated protein kinase pathway controls interleukin 4 receptor function and type-2 helper T cell differentiation

The central role of type-2 helper T (Th2) cells in the development of allergic responses and immune responses against helminthic parasites is well documented. The differentiation of Th2 cells from naive T cells requires both the recognition of antigen by T cell antigen receptors (TCR) and the activation of downstream signal-transduction molecules of the interleukin 4 receptor (IL-4R) pathway, including Jak1, Jak3, and STAT6. Little is known, however, about how these two distinct pathways cooperate with each other to induce Th2 cells. Here, we use a T cell-specific H-Ras-dominant-negative transgenic mouse to show that TCR-mediated activation of the Ras/mitogen-activated protein kinase pathway alters IL-4R function and is required for Th2 cell differentiation. The enhancement of IL-4R signaling seems to be a consequence of both direct "crosstalk" with the TCR signaling pathway and increased protein expression of downstream signaling molecules of the IL-4R pathway. Therefore, successful Th2 differentiation depends on the effectiveness of the TCR-mediated activation of the Ras/mitogen-activated protein kinase pathway in modifying the IL-4R-mediated signaling pathway.     

Synthesis of Urethane Derivatives of Mono- and Diacylglycerols for Use as HPLC Standards in the Enantiomeric Separation

This paper presents a convenient method for the preparation of reference standards for high-performance liquid chromatography (HPLC) used in stereospecific analysis of triacyl-sn-glycerols via monoacylglycerol or diacylglycerol intermediates. In the analysis, these partial acylglycerols are separated into their respective positional and enantiomeric isomer classes by chiral HPLC as their 3,5-dinitrophenylurethane derivatives or by silicic acid HPLC as their (S)- or (R)-1-(1-naphthyl)ethyl urethane derivatives. In this study, these urethane derivative standards were synthesized by the following novel procedure: first, partial urethane derivatives of glycerol were prepared by carbamoylation of glycerol with isocyanates; secondly, the products were separated into positional isomer classes by silicic acid HPLC, and; finally, a fatty acid was added to the partial urethanes using N,N′-dicyclohexylcarbodiimide. The identities of the resulting urethane derivatives of glycerol were verified by mass spectrometry and HPLC. This new procedure is advantageous in that standard urethane derivatives of partial acylglycerols can be synthesized from no more than 50 μg of fatty acids. This benefit is especially important in the case of rare and expensive fatty acids, such as very long chain polyunsaturated fatty acids, tetracosahexaenoic acid, and hexacosaheptaenoic acid, found in marine lipids.     

Nonequilibrium quantum transport properties of a silver atomic switch

Combining nonequilibrium Green's function technique with density functional theory, electron transport, and structural properties of an Ag atomic switch through Ag2S have been investigated. We have found that an Ag atomic conductance channel in Ag2S is generated after structure optimization, resulting in large enhancement of the electron transmission coefficient at the Fermi level and metallic behavior of the Ag-Ag2S-Ag system. Such spontaneous metallization at the Ag-Ag2S interface may play an important role in fast switching of the Ag-Ag2S atomic switch.     

Adaptively controlled supercontinuum pulse from a microstructure fiber for two-photon excited fluorescence microscopy

Selective fluorescence excitation of specific molecular species is demonstrated by using coherent control of two-photon excitation with supercontinuum pulses generated with a microstructure fiber. Pulse shaping prior to pulse propagation through the fiber is controlled by a self-learning optimization loop so that the highest fluorescence signal contrast between two fluorescent proteins is obtainable. The self-learning optimization loop successfully controls both the optical nonlinarity of the microstructure fiber and the two-photon excitation of the fluorescent proteins.     

Performance of a partially packed charcoal pellet bioreactor for acetic acid fermentation

The performance of a partially packed charcoal pellet bioreactor was compared to that of a fully packed bioreactor for aerobic acetic acid production. In the fully packed charcoal pellet bioreactor, it was considered that the shortening of an actual retention time of the culture broth limited the bioreactor performance under high dilution rate and high aeration conditions. By reducing the filling ratio of charcoal pellets to 44%, which increased the actual retention time of the culture broth, the maximum productivity increased from 3.9 g/l/h in the fully packed bed bioreactor to 5.7 g/l/h in the partially packed bioreactor without affecting the operational stability.     

Induction of macrophage migration inhibitory factor messenger ribonucleic acid in rat forebrain by reperfusion

To evaluate the impact of uremia and associated caloric restriction on physiologically pulsatile growth hormone (GH) release, we used deconvolution analysis of spontaneous plasma GH profiles in 5/6-nephrectomized male rats (NX, N = 9). Three different normal renal function sham-operated groups were used: rats fed a normal diet ad libitum (SAL, N = 9); NX pair-fed rats (SPF, N = 6); NX rats pair-fed for protein ingestion but calorically supplemented up to the energy intake of SAL (SPF+, N = 8). Severe renal failure was confirmed by much higher (P < 0.001) BUN in NX than sham groups. NX rats were growth retarded as shown by reduced (P < 0.01) weight and length gains as compared with sham animals. Deconvolution analysis (mean +/- SEM) of plasma samples obtained every 10 minutes over 6 hours, and 14 to 16 days after second stage nephrectomy showed that NX rats had a longer GH t(1/2) (17.0 +/- 1.8 vs. 11.6 +/- 0.8 min), less GH mass secreted per burst (48 +/- 15 vs. 95 +/- 16 ng/ml/pulse), lower secretory pulse amplitude (1.9 +/- 0.5 vs. 5.8 +/- 0.9 ng/ml/min), and a reduced total GH secretion (240 +/- 69 vs. 400 +/- 56 ng/ml/6 hr) than SAL rats. Corresponding data were not significantly different between NX and SPF, or between SAL and SPF+ groups. In summary, stunted rats with chronic renal failure exhibit a prolonged GH t(1/2) and suppression of GH secretory pattern burst mass. Control data from rats with normal renal function suggest that the amplitude-specific depression of GH secretion may be attributed, at least in part, to chronic renal failure-associated calorie deficiency.     

3D-Printed Methane-Producing Electrodes for Microbial Fuel Cells Developed Using Biogel Ink Containing Live Methanogens and White Charcoal

Methanogens are used as catalysts for cathodes in microbial fuel cells, to reduce CO₂ to CH₄. However, the attachment of microbes to the electrodes via culturing is time-consuming, and inadequate biofilm formation can lead to lesser surface area coverage, resulting in reduced methane formation. This study aims to improve the production efficiency and performance of methanogen cathodes developed using 3D printing of bioink containing live methanogens. A progressive cavity pump is used for the 3D gel-printing of methanogens and micro-sized white charcoal particles into the desired structure. Despite the absence of anaerobic conditions during printing, the 3D-printed cathodes with higher concentrations of microbial inoculum in the bioink produce more methane gas. Even with an unconcentrated inoculum, the methanogens multiply 800-fold during incubation, resulting in increased methane gas production. The predominant methanogens in the electrodes included the hydrogenotrophic Methanobacterium spp. Therefore, the technique used in this study can be used to successfully develop 3D-printed biocathodes catalyzed by methanogenic microbes with verifiable practical applicability. This study is the first to report the growth of methanogens and their methanogenic activity in 3D-printed cathodes.     

Comparison of antimicrobial resistance between the type strain of Lactococcus lactis and isolates from coastal environments

To ensure the safety of dairy products, a comparison was made between coastal-derived Lactococcus lactis strains and the type strain regarding antimicrobial resistance (AMR) and their genes. The test discs revealed that the AMR of 31 strains against streptomycin, gentamicin and kanamycin was higher than that of the type strain. The clear zone ratio of the type strain to that of Himuka-SU2 was 3.0–3.5. However, both strains exhibited identical AMR genes. Pre-incubation in broth containing 3.4% (w/v) NaCl increased the AMR of the type strain compared to the Himuka-SU2 strain. These results are significant for the development of starters for fermented milk.