Advances in the production of chemicals by organelle compartmentalization in Saccharomyces cerevisiae / 生物工程学报

As a generally-recognized-as-safe microorganism, Saccharomyces cerevisiae is a widely studied chassis cell for the production of high-value or bulk chemicals in the field of synthetic biology. In recent years, a large number of synthesis pathways of chemicals have been established and optimized in S. cerevisiae by various metabolic engineering strategies, and the production of some chemicals have shown the potential of commercialization. As a eukaryote, S. cerevisiae has a complete inner membrane system and complex organelle compartments, and these compartments generally have higher concentrations of the precursor substrates (such as acetyl-CoA in mitochondria), or have sufficient enzymes, cofactors and energy which are required for the synthesis of some chemicals. These features may provide a more suitable physical and chemical environment for the biosynthesis of the targeted chemicals. However, the structural features of different organelles hinder the synthesis of specific chemicals. In order to ameliorate the efficiency of product biosynthesis, researchers have carried out a number of targeted modifications to the organelles grounded on an in-depth analysis of the characteristics of different organelles and the suitability of the production of target chemicals biosynthesis pathway to the organelles. In this review, the reconstruction and optimization of the biosynthesis pathways for production of chemicals by organelle mitochondria, peroxisome, golgi apparatus, endoplasmic reticulum, lipid droplets and vacuole compartmentalization in S. cerevisiae are reviewed in-depth. Current difficulties, challenges and future perspectives are highlighted.

Correlation between bone mineral density and neutrophil/lymphocyte ratio in patients with rheumatoid arthritis / 中华风湿病学杂志

Objective:To investigate the relationship between neutrophil/lymphocyte ratio (NLR) and bone mineral density (BMD) in rheumatoid arthritis (RA), and to evaluate its diagnostic value in RA with osteoporosis.Methods:134 RA patients and 69 healthy subjects were screened and NLR levels were compared between the two groups. Bone mineral density of lumbar L1-4 and femoral neck was measured by dual energy X-ray absorption (DXA), and the patients were divided into normal bone mass group (44 cases), reduced bone mass group (47 cases) and osteoporosis group (43 cases). Height, weight, course of disease, mean platelet volume, erythrocyte sedimentation rate (ESR), C-reactionprotein (CRP), complement C3, complement C4, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, bone mineral density and other related indicators were recorded. The differences of NLR, body mass index(BMI) gender, age and other indicators among the three groups were compared by One-way Analysis of Variance (ANOVA) and Kruskal-Wallis test, or χ2 test. Correlation analysis was conducted to detect the correlation between NLR, bone mass and each indicator, and ordered multi-classification Logistic regression analysis was used to evaluate the im-pact of each indicator on osteoporosis, and receiver operating characteristic curve (ROC) was used to predict the diagnostic value of NLR and combined related indicators on osteoporosis. Results:NLR of RA patients (3.1±1.7) was higher than that of healthy controls (1.7±0.5) ( F=21.27, P<0.001). In the osteoporosis group, the reduced bone mass group, and the normal bone mass group, age (66±8), (62±10), (50±13), disease course (15±10), (9±8, (7±7), BMI (20±4) kg/m 2, (22±3) kg/m 2, (24±3) kg/m 2, NLR (3.9±2.3, 2.7±1.2, 2.6±1.0), CRP (41±43) mg/L, (28±34) mg/L, (18±26) mg/L, ESR (46±30) mm/1 h, (36±26) mm/1 h, (26±20) mm/1 h were significantly different among the three groups ( χ2=32.92, P<0.001; H=17.41, P<0.001; F=12.04, P<0.001; H=11.62, P=0.030; H=13.78, P=0.001; F=7.18, P=0.001). Correlation analysis showed that NLR was correlated with CRP, ESR, anti-CCP antibody, femoral neck bone mineral density, DAS28 score and age. The correlation coefficients were 0.49 ( P<0.001), 0.39 ( P<0.001), 0.30( P<0.001), -0.18( P=0.042), 0.50( P<0.001), 0.17( P=0.046), respectively. Femoral neck was correlated with age, BMI, course of disease, CRP, ESR. The correlation coefficients were -0.46( P<0.001), 0.38 ( P<0.001),-0.39 ( P<0.001), -0.34 ( P<0.001), the correlation coefficients of L1-4 with age, BMI, CRP and ESR were -3.41( P<0.001), 0.39( P<0.001), -0.22( P=0.010), -2.42( P=0.005), respectively. There was no correlation between bone mineral density and DAS28 and anti-CCP antibody. Ordered multi-classification Logistic regression analysis showed that: age, course of disease, NLR and ESR were risk factors for osteoporosis, and their OR values were 1.12 ( P<0.001), 1.05 ( P=0.025), 1.29 ( P=0.031), 1.02 ( P=0.039), 0.28 ( P=0.008), respectively. Body mass index ( OR=0.76, P<0.001) were protective factors. ROC curve showed that the AUC area of NLR was 0.68, the AUC area of NLR, BMI, age, sex and course of disease was 0.90, the cut-off value was 0.20, sensitivity was 0.95, and specificity was 0.73[95% CI(0.84, 0.95)]. Conclusion:In osteoporosis, NLR is related to bone mass and disease activity of patients with rheumatoid arthritis. Combined with other related indexes, NLR can be used as a predictive diagnostic index and has a guiding role in clinical practice.

Progress in studies on production of chemicals from xylose by Saccharomyces cerevisiae / 生物工程学报

Effective utilization of xylose is a basis for economic production of biofuels or chemicals from lignocellulose biomass. Over the past 30 years, through metabolic engineering, evolutionary engineering and other strategies, the metabolic capacity of xylose of the traditional ethanol-producing microorganism Saccharomyces cerevisiae has been significantly improved. In recent years, the reported results showed that the transcriptome and metabolome profiles between xylose and glucose metabolism existed significant difference in recombinant yeast strains. Compared with glucose, the overall process of xylose metabolism exhibits Crabtree-negative characteristics, including the limited glycolytic pathway activity, which reduces the metabolic flux of pyruvate to ethanol, and the enhanced cytosolic acetyl-CoA synthesis and respiratory energy metabolism. These traits are helpful to achieve efficient synthesis of downstream products using pyruvate or acetyl-CoA as precursors. This review provides a detailed overview on the modification and optimization of xylose metabolic pathways in S. cerevisiae, the characteristics of xylose metabolism, and the construction of cell factories for production of chemicals using xylose as a carbon source. Meanwhile, the existed difficulties and challenges, and future studies on biosynthesis of bulk chemicals using xylose as an important carbon source are proposed.

Expression of interleukin-6 and hepcidin in diffuse large B-cell lymphoma and their relationship with anemia / 白血病·淋巴瘤

Objective To study the expression of interleukin-6 (IL-6) and hepcidin in patients with diffuse large B-cell lymphoma (DLBCL) and their significance in anemia. Methods 45 DLBCL patients with or without anemia were analyzed. Peripheral blood samples were collected during diagnosis, and the concentrations of IL-6, hepcidin, serum ferritin and hemoglobin (Hb) were measured. 24 healthy volunteers were collected as controls. Results The levels of plasma hepcidin and IL-6 in patients with DLBCL were (347±171)μg/L and 0.27 ng/L (0-9.61 ng/L), respectively, and compared with those [(175 ± 92)μg/L] and 0 ng/L in healthy controls, the differences were statistically significant (both P1 (P=0.010) were increased. The levels of IL-6 in patients of male (P=0.003), stage Ⅲ-Ⅳ (P=0.008) or IPI>1 (P=0.004) were significantly higher. The level of hepcidin was highly correlated with serum ferritin (r=0.77, P<0.001), weakly correlated with IL-6 (r=0.31, P=0.030), and not correlated with Hb (r=-0.12, P=0.3). There was a negative correlation between IL-6 expression and Hb (r=-0.35, P=0.009). Multivariate analysis showed that IL-6 could predict anemia (P=0.03), whereas hepcidin could not (P=0.89). Conclusion The elevated hepcidin level is frequent in DLBCL, and the elevated IL-6 plays the major role in the development of anemia.

Experimental therapeutic effect of combined cytokines on beagle dogs exposed to 4.5 Gy γ-rays / 中华放射医学与防护杂志

Objective To evaluate the effects of combined administration of recombinant human interleukin-11(rhIL-11),recombinant human G-CSF(rhG-CSF)and recombinant human interleukin-2 (rhIL-2)on acute radiation sickness(ARS)beagles.Methods Sixteen beagle were irradiated with 4.5 Gy60 Co γ-rays to establish ARS models,and were divided into irradiation control group,supportive care group and combined cytokines treatment group.After irradiation irradiation control group was given no treatment,the dogs in supportive care group received purely symptomatic treatment,while combined cytokines treatment group received rhIL-11 50μg/(kg·d)and rbG-CSF 10μg/(kg·d)subcutaneously(0-14 d)and rhIL-2 1×1 06 U/d(29-43 d)besides symptomatic treatment.Manifestation and characteristics of ARS beagles were observed,and the survival time were recorded.At last,post-mortem examination and histological examination were performed.Results All animals underwent nausea,diarrhea and fever.After irradiation,all animals in irradiation control group died in two weeks,and the mean survival time was 12.7 d,while only one died at 33 d in supportive care group.All dogs in combined cytokine group survived at 45 day after exposure,and their haematopoiesis and gastrointestinal tract were recovered.Conclusions Combination of rhIL-11 + rhG-CSF + rhIL-2 treatment could be significantly effective on ARS beagles irradiated by 4.5 Gy60 Co γ-rays,which could accelerate injured haemotopoiesis and intestinal tract recovery,increase the survival rate and improve the life quality of animals.

Therapeutic effects of combined cytokines on hematopoietic injuries induced by 4.5 Gy γ-rays irradiation in beagles / 中华放射医学与防护杂志

Objectivc To observe the therapeutic effects of combined cytokines on hematopoietic injuries induced by 4.5 Gy60 Co γ-rays irradiation in beagles,and to provide experimental evidences for the clinical treatment of extremely severe myeloid acute radiation sickness(ARS).Methods 16 beagles were given 4.5 Gy60 Co γ-rays total body irradiation,and then randomly assigned into irradiation control group,supportive care group and cytokines group.In addition to supportive care,recombinant human granulocyte colony-stimulating factor (rhG-CSF),recombinant human interleukin-11(rhIL-11)and recombinant human interleukin-2(rhIL-2)were administered subcutaneouly to dogs in cytokines group.Peripheral blood hemogram was examined once every two days.Bone marrow and peripheral blood were collected to proceed colony cultivation 4 d pre-irradiation and 1 and 45 d post-irradiation.Conventional histopathological sections of sternum were prepared to observe the histomorphology changes. Results After irradiation,the population of all kinds of cells in peripheral blood declined sharply.WBC nadir Was elevated(1.04×109/L,but 0.28×109/L and 0.68×109/L for the irradiation control group and the supportive care group separately),the duration of thrombocytopenia was shortened (24 days,but 33 days for the supportive care groug) and red blood cell counts were maintained in the range of normal values after cytokincs treatment in combination.The colony forming efficiency of haemopoietic stem cells(HSCs)in bone marrow and peripheral blood decreased obviously 1 d post irradiation,but recovered to the level of that before irradiation 45 d post irradiation after supportive care and cytokines treatment.Hematopoietic cells disappeared in bone marrow of animals in irradiation control group,but hematopoietic functions were recovered after cytokines were administrated.Conclusions RhG-CSF.rhIL-11 and rhIL-2 used in combination could elevate WBC nadir,accelerate the recovery of leukocytes,platelets and red blood cells and promote the proliferation,differentiation and maturity of HSPCs left in the body after 4.5 Gy γ-rays total body irradiation,eventually restore the hematopoietic function.Hence,combination of rhG-CSF,rhIL-11 and rhIL-2 could serve as better therapeutic strategy to treat extremely severe myeloid ARS.