Characteristics of amino acid metabolism in myeloid-derived suppressor cells in septic mice / 北京大学学报(医学版)

OBJECTIVE@#To explore the amino acid metabolomics characteristics of myeloid-derived suppressor cells (MDSCs) in mice with sepsis induced by the cecal ligation and puncture (CLP).@*METHODS@#The sepsis mouse model was prepared by CLP, and the mice were randomly divided into a sham operation group (sham group, n = 10) and a CLP model group (n = 10). On the 7th day after the operation, 5 mice were randomly selected from the surviving mice in each group, and the bone marrow MDSCs of the mice were isolated. Bone marrow MDSCs were separated to measure the oxygen consumption rate (OCR) by using Agilent Seahorse XF technology and to detect the contents of intracellular amino acids and oligopeptides through ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) technology. Different metabolites and potential biomarkers were analyzed by univariate statistical analysis and multivariate statistical analysis. The major metabolic pathways were enriched using the small molecular pathway database (SMPDB).@*RESULTS@#The proportion of MDSCs in the bone marrow of CLP group mice (75.53% ± 6.02%) was significantly greater than that of the sham group (43.15%± 7.42%, t = 7.582, P < 0.001), and the basal respiratory rate [(50.03±1.20) pmol/min], maximum respiration rate [(78.07±2.57) pmol/min] and adenosine triphosphate (ATP) production [(25.30±1.21) pmol/min] of MDSCs in the bone marrow of CLP group mice were significantly greater than the basal respiration rate [(34.53±0.96) pmol/min, (t = 17.41, P < 0.001)], maximum respiration rate [(42.57±1.87) pmol/min, (t = 19.33, P < 0.001)], and ATP production [(12.63±0.96) pmol/min, (t = 14.18, P < 0.001)] of sham group. Leucine, threonine, glycine, etc. were potential biomarkers of septic MDSCs (all P < 0.05). The increased amino acids were mainly enriched in metabolic pathways, such as malate-aspartate shuttle, ammonia recovery, alanine metabolism, glutathione metabolism, phenylalanine and tyrosine metabolism, urea cycle, glycine and serine metabolism, β-alanine metabolism, glutamate metabolism, arginine and proline metabolism.@*CONCLUSION@#The enhanced mitochondrial oxidative phosphorylation, malate-aspartate shuttle and alanine metabolism in MDSCs of CLP mice may provide raw materials for mitochondrial aerobic respiration, thereby promoting the immunosuppressive function of MDSCs. Blocking the above metabolic pathways may reduce the risk of secondary infection in sepsis and improve the prognosis.

Alanine mother liquor as a nitrogen source for docosahexaenoic acid production by Schizochytrium sp. B4D1

Alanine mother liquor, a type of industrial waste from alanine fermentation, was used as a nitrogen source to produce docosahexaenoic acid (DHA) by Schizochytrium sp. B4D1. The results indicated that yeast extract could trigger the utilization of the alanine mother liquor. Additionally, the alanine can be quenched during the culture, which aids in DHA accumulation. The medium components were optimized via response surface methodology as follows: 99.98-g/L glucose, 0.05-g/L yeast extract and a 183.17 dilution factor of the alanine mother liquid (v/v, with an alanine content of 0.72 g/L) and 17.98% inoculum concentration (v/v). Finally, in a 50-mL shake-flask fermentation, the DHA yield was 2.29 g/L.

The homotrimeric structure of HtrA2 is indispensable for executing its serine protease activity

Serine protease activity of high temperature requrement 2 (HtrA2) is essential for promoting cell death, as well as for protecting against cellular stresses. An X-ray crystallographic study described the formation of a pyramid shaped homotrimer that is a proteolytically competent form of HtrA2; however, little is known about effects of the trimeric structure of HtrA2 on the natural substrates. In this study, we generated the HtrA2 protein that has a single point mutation at the homotrimerization motif to assess relationship between structure and the proteolytic activity of HtrA2 on its substrates. Using gel filtration, a native gel electrophoresis system, and a co-precipitation assay, we confirm that phenylalanine 149 in HtrA2 is a crucial determinant for the formation of the HtrA2 homotrimeric structure. Moreover, we described that the HtrA2 monomeric form abolished not only autoproteolytic activity, but also the proteolytic activity against XIAP (X-linked inhibitor of apoptosis protein) known as the HtrA2 substrate. Taken together, the results indicate that the homotrimeric structure of HtrA2 is required for executing its serine protease activity.

Detection of an Ala601Thr Mutation of Plasminogen Gene in 3 out of 36 Korean Patients with Deep Vein Thrombosis

Plasminogen is a key proenzyme in the fibrinolytic and thrombolytic systems. Congenital deficiency of plasminogen and molecular abnormality of plasminogen (dysplasminogenemia) have been reported in association with the thrombotic tendency in human. In dysplasminogenemia, the level of immunoreactive plasminogen is normal, although the functional activity is reduced. Human plasminogen gene spans about 52.5 kb of DNA and consists of 19 exons. Three types of mutations (Ala601Thr, Val355Phe, and Asp676Asn) have been described in dysplasminogenemia. In this study, we measured the plasminogen activity in patients with deep vein thrombosis and analyzed the DNA sequence to detect three point mutations (Ala601Thr, Val355Phe and Asp676Asn) in patients with hypo/dysplasminogenemia. Dysplasminogenemia was identified in 3 (8.3%) of unrelated 36 patients with deep vein thrombosis and the Ala601Thr mutation was detected in all three patients with dysplasminogenemia. In conclusion, dysplasminogenemia is not rare in deep vein thrombosis, which suggests a risk factor for the thrombosis in Korean population.

Espectroscopia por ressonância magnética em epilepsia / Magnetic resonance spectroscopic imaging in epilepsy

A evoluçäo da cirurgia para epilepsia vem sendo acompanhada por novos métodos de neuroimagem, näo só morfológicos, como, também, funcionais. Dentre esses últimos, destacamos a espectroscopia por ressonância magnética (ERM), de especial interesse deste artigo. A ERM parece ser promissora na definiçäo da identificaçäo do foco epileptogênico, pela demonstraçäo das alteraçöes dos metabólicos do fósforo (31P-ERM) e avaliaçäo pelo próton de H+ (1H-ERM). Reconhece-se a variaçäo da 1H-ERM normal, segundo alteraçöes idade-relacionadas, para localizaçäo do foco epileptogênico, no período interictal, pelas taxas de NAA (N-acetilaspartato), Cr (creatina) e Co (colina), e relaçöes NAA: Co e NAA: Cr; e no ictal, pelas mesmas taxas e pela avaliaçäo do lactato. A estimativa de aminoácidos neurotransmissores também auxilia nessa topografia. A ERM, em especial, a 1H-ERM, é de grande potencialidade no estudo bioquímico do cérebro, in vivo, e poderá vir a ter crescente importância no diagnóstico topográfico da regiäo epileptogênica dos pacientes com epilepsia, na dependência da idade e do local do foco

Alterations in metabolic activity of Cysticercus fasciolaris on some anthelmintic treatments.

Effect of candidate compounds 81-470 i.e. methyl [5[4-(2-pyridinyl)-1-piperazinyl]carbonyl]-1H-benzimidazole-2-yl]- carbamate and 86-162 i.e. methyl-5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate along with reference drugs mebendazole and praziquantel on energy metabolism of C. fasciolaris recovered from rats treated with single dose of 500 mg/kg, ip was investigated. All the drugs significantly lowered the rate of uptake of glucose and alanine by the parasite. Suppression in the formation of lactate, the major end-product, was also noticed. Nonetheless the ratio of lactate produced versus the substrates consumed was not substantially affected. The recovered cysticerci also possessed less glycogen and ATP compared to the normal parasites. Although the effects exerted by the drugs were of the identical nature, they significantly differed in the magnitude of their action. Mebendazole followed by praziquantel maximally affected all the above metabolic activities while 86-162 proved to be the weakest in action. The results suggest that the examined drugs exert their chemotherapeutic activity by interfering with uptake of glucose and alanine but do not significantly alter their catabolism.

Products of non-reductive CO2 assimilation in the halophilic archaebacterium Haloferax mediterranei.

The products of CO2 fixation by heterotrophically grown Haloferax mediterranei were analysed. The main 14C-labelled alpha-ketoacid detected following incubation with NaH14CO3 and pyruvate or propionate was pyruvate. In presence of these organic acids and NH4+, 14CO2 was incorporated into glutamic and aspartic acids and alanine.

El enlace O-glicosídico en glicoproteínas de plasma seminal humano / The linkage O-glycosidic in glycoproteins of human seminal plasma

La composición y estructura de los extremos terminales no reductores portadores de los determinantes antigénicos en las cadenas de oligosacáridos de las glicoproteínas del plasma seminal humano, han permitido deducir que estos componentes son fragmentos producidos por la degradación proteolítica endógena de las mucinas. Dado que las cadenas de hidratos de carbono unidas O-glicosídicamente a la serina y la treonina de la cadena peptídica dan lugar a una reacción de beta-eliminación en condiciones alcalinas suaves, hicimos uso del tratamiento alcalino para demostrar la presencia de enlaces lábiles al álcali en las muestras de plasma seminal humano y algunas fracciones glicoproteicas aisladas a partir del mismo. El análisis de los hidratos de carbono que se liberan durante ell tratamiento han permitido obtener información sobre la composición y estructura de este tipo de unidades de oligosacarídos. Hemos identificado al monosacárido involucrado en el enlace O-glicosídico a serina y treonina y hemos podido caracterizar, a través de la reacción de beta-eliminación en condiciones reductoras y no reductoras, las unidades de monosacáridos del extremo terminal reductor