Biochemical parameters of Saccharopolyspora erythraea during feeding ammonium sulphate in erythromycin biosynthesis phase

The physiology of feeding ammonium sulphate in erythromycin biosynthesis phase of Saccharopolyspora erythraea on the regulation of erythromycin A (Er-A) biosynthesis was investigated in 50 L fermenter. At an optimal feeding ammonium sulphate rate of 0.03 g/L per h, the maximal Er-A production was 8281 U/mL at 174 h of growth, which was increased by 26.3% in comparison with the control (6557 U/mL at 173 h). Changes in cell metabolic response of actinomycete were observed, i.e. there was a drastic increase in the level of carbon dioxide evolution rate and oxygen consumption. Assays of the key enzyme activities and organic acids of S. erythraea and amino acids in culture broth revealed that cell metabolism was enhanced by ammonium assimilation, which might depend on the glutamate transamination pathway. The enhancement of cell metabolism induced an increase of the pool of TCA cycle and the metabolic flux of erythromycin biosynthesis. In general, ammonium assimilation in the erythromycin biosynthesis phase of S. erythraea exerted a significant impact on the carbon metabolism and formation of precursors of the process for dramatic regulation of secondary metabolites biosynthesis.

Recombinant PTD-Cu/Zn SOD attenuates hypoxia-reoxygenation injury in cardiomyocytes

BACKGROUND

Oxidative stress plays a pivotal role in myocardial ischemia-reperfusion injury. Increasing the protein expression of intracellular Cu/Zn SOD, which is the major endogenous antioxidant enzyme, may attenuate or prevent hypoxia-reoxygenation injury (HRI) in cultured cardiomyocytes. However, ectogenic Cu/Zn-SOD can hardly be transferred into cells to exert biological effects. In this study, we constructed PTD-Cu/Zn SOD plasmid with a kind of translocation structure-Protein transduction domain (PTD) and detected its transmembrane ability and antioxidant effects in H9c2 rat cardiomyocytes subjected to hypoxia/reoxygenation injury (HRI).

METHODS

We constructed the pET-PTD-Cu/Zn SOD (CDs) prokaryotic expression vectors in plasmid that were inserted into E. coli BL21 to induce the protein expression of PTD-Cu/Zn SOD. H9c2 cardiomyocyte HRI was achieved by exposing cardiomyocytes to 12 h hypoxia followed by 2 h reoxygenation. Protein expression of PTD-Cu/Zn SOD in cardiomyocytes was assayed by Western blot and their enzyme activities were investigated by immunohistochemistry and flow cytometry.

RESULTS

In cultured cardiomyocytes hypoxia-reoxygenation injury model, exogenous PTD-Cu/Zn SOD could penetrate cell membrane to clear superoxide anion and decrease hydrogen peroxide level in H9c2 cardiomyocytes subjected to HRI. The level of mitochondrial membrane potential was restored to normal, and the cell apoptosis was reduced in cardiomyocytes with PTD-Cu/Zn SOD treatment during HRI.

CONCLUSION

Recombinant PTD-Cu/Zn SOD could scavenge intracellular-free superoxide anion, protect mitochondria from damages, and attenuate the hypoxia-reoxygenation injury in cultured cardiomyocytes.

Abstract P4-05-01: Oncolytic Herpes Simplex Virus Vector G47Δ Effectively Targets Breast Cancer Stem Cells

Breast tumors can be classified according to their gene-expression profiles into different molecular subtypes with distinct biological and clinical features. Moreover, different subtypes show distinct responses to different therapeutic regimens, thereby resulting in markedly different outcomes. Recently, accumulating evidence has suggested that breast cancer originates from cancer stem cells (CSCs), which comprise a small percentage of the overall tumor but are highly tumorigenic and pluripotent with unlimited proliferation potential. Furthermore, cancer stem cells are highly resistant to conventional treatment, which potentially explains certain difficulties in treating cancer with current therapy options. The use of oncolytic viruses is a relatively new strategy in cancer therapy, oncolytic herpes simplex virus (oHSV) has been shown to be a safe and effective therapeutic approach for a variety of different cancers.

In this study, different types of breast cancer cell lines were cultured in anchorage-independent conditions, the cells typically form mammospheres within 10 days of anchorage-independent culture, which showed properties of CSCs. The mammospheres are capable of being passaged indefinitely and single dissociated mammosphere cells were able to regenerate spheres. Moreover, compared to the parental cell lines, mammoshpere cells were enriched for CD44+CD24− cells and highly expression of the alternative breast cancer stem cell marker ALDH-1.

The third generation oHSV vector G47Δ effectively killed different subtypes of breast cancer cells in vitro, with more than 98% of the tumor cells killed by day 5, even at multiplicities of infection(MOI) 0.01. Moreover, G47Δ equally targeted non-cancer stem cells (NCSCs) and CSCs which showed resistance to paclitaxel. We also demonstrated that G47Δ effectively replicated and spread among CSCs. Moreover, G47Δ impaired the self-renewal ability of CSCs, as the viable cells unable to form secondary tumor spheres. We also showed that G47Δ was able to induce the regression of tumor xenografts in BALB/c nude mice and demonstrated the ability of G47Δ to synergize with paclitaxel for killing both NCSCs and CSCs. This is the first report that oHSV effectively targets different breast cancer NCSCs and CSCs, thereby suggesting that oHSV may be an effective treatment modality for patients with breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-05-01.

The correlation of HLA allele frequencies and HLA antibodies in sensitized kidney transplantation candidates

BACKGROUND

The clinical importance of the HLA system is as a transplant antigen. However, correlations between the development and strength of the immune response and HLA genes or specific foreign antigens are not clear.

OBJECTIVES

The objectives of this study were to detect HLA-A, -B, and -DRB1 allele frequencies and HLA antibodies in sensitized patients, and to investigate the correlation between the HLA alleles and HLA sensitization.

METHODS

This study included 383 sensitized patients and 1000 unsensitized patients awaiting kidney transplantation from 2001-2010. HLA -A, -B, and -DRB1 typing was performed using sequence-specific primer-polymerase chain reactions (SSP-PCR). Arlequin statistical analysis software was used to calculate the HLA allele frequencies among the 2 groups. The anti-HLA-specific antibodies of sensitized patients were identified and analyzed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The numbers of identified HLA -A, -B, and -DRB1 alleles were 20, 43, and 14, respectively. The 5 most frequent HLA alleles in the 2 groups were not different: A-02, 11, 24, 33, 26; B-46, 60, 13, 75, 58; and DR-9, 15, 12, 4, 14. Among the sensitized group, the most frequent HLA-specific antibodies were as follows: A-2, 24, 68, 23, 32; B-27, 56, 57, 7, 60; and DR-7, 4, 9, 13, 17.

CONCLUSIONS

There was little correlation between HLA sensitization and HLA alleles of oneself. High frequency alleles and the specificity of high-frequency HLA antibodies were not consistent.

Non-viral transfection of goat germline stem cells by nucleofection results in production of transgenic sperm after germ cell transplantation

Germline stem cells (GSCs) can be used for large animal transgenesis, in which GSCs that are genetically manipulated in vitro are transplanted into a recipient testis to generate donor-derived transgenic sperm. The objectives of this study were to explore a non-viral approach for transgene delivery into goat GSCs and to investigate the efficiency of nucleofection in producing transgenic sperm. Four recipient goats received fractionated irradiation at 8 weeks of age to deplete endogenous GSCs. Germ cell transplantations were performed 8-9 weeks post-irradiation. Donor cells were collected from testes of 9-week-old goats, enriched for GSCs by Staput velocity sedimentation, and transfected by nucleofection with a transgene construct harboring the human growth hormone gene under the control of the goat beta-casein promoter (GBC) and a chicken beta-globin insulator (CBGI) sequence upstream of the promoter. For each recipient, transfected cells from 10 nucleofection reactions were pooled, mixed with non-transfected cells to a total of 1.5 × 10(8) cells in 3 ml, and transplanted into one testis (n = 4 recipients) by ultrasound-guided cannulation of the rete testis. The second testis of each recipient was removed. Semen was collected, starting at 9 months after transplantation, for a period of over a year (a total of 62 ejaculates from four recipients). Nested genomic PCR for hGH and CBGI sequences demonstrated that 31.3% ± 12.6% of ejaculates were positive for both hGH and CBGI. This study provides proof-of-concept that non-viral transfection (nucleofection) of primary goat germ cells followed by germ cell transplantation results in transgene transmission to sperm in recipient goats.

A66G and C524T polymorphisms of the methionine synthase reductase gene are associated with congenital heart defects in the Chinese Han population

Congenital heart defects (CHDs) are the most common birth defects; genes involved in homocysteine/folate metabolism may play important roles in CHDs. Methionine synthase reductase (MTRR) is one of the key regulatory enzymes involved in the metabolic pathway of homocysteine. We investigated whether two polymorphisms (A66G and C524T) of the MTRR gene are associated with CHDs. A total of 599 children with CHDs and 672 healthy children were included; the polymorphisms were detected by PCR and RFLP analysis. Significant differences in the distributions of A66G and C524T alleles were observed between CHD cases and controls, and slightly increased risks of CHD were associated with 66GG and 524CT genotypes (odds ratios = 1.545 and 1.419, respectively). The genotype frequencies of 524CT in the VSD subgroup, 66GG and 524CT in the PDA subgroup were significantly different from those of controls. In addition, the combined 66AA/524CT, 66AG/524CT and 66GG/524CT in CHDs had odds ratios = 1.589, 1.422 and 1.934, respectively. Increased risks were also observed in 66AA/524CT and 66GG/524CT for ASD, 66AG/524CT for VSD, as well as 66GG/524CT for PDA. In conclusion, MTRR A66G and C524T polymorphisms are associated with increased risk of CHDs.

Zinc finger protein A20 overexpression inhibits monocyte homing and protects endothelial cells from injury induced by high glucose

Diabetes mellitus causes vascular lesions and may ultimately lead to atherosclerosis. One of the earliest steps in the development of atherosclerotic lesions is the adhesion of monocytes to endothelial cells of the vessel wall. It is currently unknown whether zinc finger protein A20 is able to protect endothelial cells from injury caused by high levels of glucose and monocyte homing. In our study, adhesion of monocytes to the vessel wall endothelium was detected by measuring the rolling velocity of monocytes along human umbilical vein endothelial cells (HUVECs). Activation of NF-κB was analyzed through Western blot. HUVEC apoptosis was monitored by TUNEL in situ end-labeling and flow cytometry. High glucose concentrations (25 mM) stimulated monocytes, reducing the velocity at which they roll along HUVECs. Stimulation of monocytes with high levels of glucose also induced HUVEC apoptosis. Overexpression of the zinc finger protein A20 inhibited monocyte recruitment, NF-κB activation, P-selectin expression, and HUVEC apoptosis induced by high glucose levels. We conclude that zinc finger protein A20 can protect HUVECs from injury induced by high levels of glucose and potentially could be used to develop treatments against diabetic vascular lesions.

Evaluation ECMO in adult cardiac transplantation: can outcomes of marginal donor hearts be improved?

AIM

This study documents our experience with the use of ECMO in adult cardiac transplantation. Furthermore, in an attempt to improve outcomes of donor hearts with long ischemic times (LITs) we evaluated the efficacy of a strategy based on intraoperative ECMO (i-ECMO) circuit extended into postoperative cardiopulmonary support.

METHODS

From February 2005 to September 2009, 11 patients (i-ECMO group) receiving allografts with LITs >7 hours underwent intraoperative ECMO circuit strategy with routine extension of ECMO into postoperative period. Eleven contemporary patients (s-CPB group) received ECMO support after standard CPB at the various intervals after the transplantation as a salvage therapy.

RESULTS

Overall weaning rate was 86.4%; overall 30-day and 1-year survival rates were 81.8% and 72.7%, respectively. There was no difference in mortality between the two groups. Length of stay in the intensive care unit, the requirement for packed red blood cells administration and the total in-hospital cost were significantly reduced in i-ECMO group patients (P<0.05).

CONCLUSION

The salvage of failing cardiac allograft with ECMO allows effective stabilization of the hemodynamic and leads toward myocardial recovery. Extending ECMO into postoperative period provides early, continues and effective support for donor hearts with LITs and maximizes the use of such marginal organs.

Anaesthetic technique may affect prognosis for ovarian serous adenocarcinoma: a retrospective analysis

BACKGROUND

Animal studies have shown that regional anaesthesia and analgesia may prevent or attenuate the surgical stress response by preserving immune function and result in better long-term outcome. We have tested the hypothesis that patients with ovarian serous adenocarcinoma who had surgery with epidural anaesthesia and analgesia would have better long-term outcome than those who were given general anaesthesia (GA) and i.v. opioid analgesia.

METHODS

A retrospective review of medical records identified 143 patients with ovarian serous adenocarcinoma who underwent surgery between January 1994 and October 2006 at the Sun Yat-sen University Cancer Center. Data in the analysis included age, anaesthesia-analgesia technique, ASA status, blood loss, transfusion, duration of surgery, status of preoperative cancer antigen 125, tumour size, International Federation of Gynecology and Obstetrics stage, histological grade, lymph node status, residual macroscopic tumour, and chemotherapy. Survival analysis was made with the main outcome measure of death.

RESULTS

The 3- and 5-yr overall survival rates were 78% and 61% in the patient group who received epidural anaesthesia and analgesia (Group E, n=106), and 58% and 49% in the patient group who received GA and i.v. opioid analgesia (Group G, n=37), respectively. After adjusting for the other variables, Group G had a hazard ratio of 1.214 (P=0.043) in a multivariable Cox regression model compared with Group E.

CONCLUSIONS

This retrospective analysis suggests that epidural anaesthesia and analgesia for ovarian serous adenocarcinoma surgery may reduce mortality during the initial years of follow-up.

Establishment of goat embryonic stem cells from in vivo produced blastocyst-stage embryos

Embryonic stem (ES) cells with the capacity for germ line transmission have only been verified in mouse and rat. Methods for derivation, propagation, and differentiation of ES cells from domestic animals have not been fully established. Here, we describe derivation of ES cells from goat embryos. In vivo-derived embryos were cultured on goat fetal fibroblast feeders. Embryos either attached to the feeder layer or remained floating and expanded in culture. Embryos that attached showed a prominent inner cell mass (ICM) and those that remained floating formed structures resembling ICM disks surrounded by trophectodermal cells. ICM cells and embryonic disks were isolated mechanically, cultured on feeder cells in the presence of hLIF, and outgrown into ES-like colonies. Two cell lines were cultured for 25 passages and stained positive for alkaline phosphatase, POU5F1, NANOG, SOX2, SSEA-1, and SSEA-4. Embryoid bodies formed in suspension culture without hLIF. One cell line was cultured for 2 years (over 120 passages). This cell line differentiated in vitro into epithelia and neuronal cells, and could be stably transfected and selected for expression of a fluorescent marker. When cells were injected into SCID mice, teratomas were identified 5-6 weeks after transplantation. Expression of known ES cell markers, maintenance in vitro for 2 years in an undifferentiated state, differentiation in vitro, and formation of teratomas in immunodeficient mice provide evidence that the established cell line represents goat ES cells. This also is the first report of teratoma formation from large animal ES cells.

Preservation and transplantation of porcine testis tissue

Grafting of immature mammalian testis tissue to mouse hosts can preserve the male germline. To make this approach applicable to a clinical or field situation, it is imperative that the testis tissue and/or spermatozoa harvested from grafted tissue are preserved successfully. The aim of the present study was to evaluate protocols for the preservation of testis tissue in a porcine model. Testis tissue was stored at 4 degrees C for short-term preservation or cryopreserved by slow-freezing, automated slow-freezing or vitrification for long-term storage. Preserved tissue was transplanted ectopically to mouse hosts and recovered xenografts were analysed histologically. In addition, spermatozoa were harvested from xenografts and cryopreserved. Total cell viability and germ cell viability remained high after tissue preservation. Complete spermatogenesis occurred in xenografts preserved by cooling up to 48 h, whereas spermatogenesis progressed to round spermatids in the xenografts that were frozen-thawed before grafting. Approximately 50% of spermatozoa harvested from xenografts remained viable after freezing and thawing. The in vivo developmental potential of cryopreserved tissue was reduced despite high post-thaw viability. Therefore, it is important to evaluate germ cell differentiation in vivo in addition to cell viability in vitro when optimising freezing protocols for testis tissue.

Air pressure pulsation solid state fermentation of feruloyl esterase by Aspergillus niger

Air pressure pulsation solid state fermentation (APP-SSF) was applied to produce feruloyl esterase (FAE) by Aspergillus niger. With the optimization of some variables by orthogonal design, the optimal condition obtained was 0.2 MPa (gauge pressure) of high pressure intensity, 30 min of low pressure duration and 20s of high pressure duration. Based on the optimized condition, the APP-SSF achieved the reasonable enzyme yield of 881 mU/g at 48 h, which was 58% more than that by static solid state fermentation (static SSF) at 72 h. By comparison of two fermentation methods in temperature, O(2) and CO(2) concentration, and respiration intensity, it was concluded that APP-SSF enhanced heat and mass transfer of fermentation system and strengthened the metabolism of microorganisms. The APP-SSF had a greatly positive effect on FAE production by A. niger, by enhancing mass and heat transfer and activating growth and metabolism.

[E-cadherin as a novel surface marker of spermatogonial stem cells]

Spermatogenesis is a fundamental biological process that ensures gee transmission from one generation to another trough gametes. This process relies on a rare population of testicular cells, called spermatogonial stem cells (SSCs), that self-renew throughout adult male life and differentiate into mature gametes. Despite the longstanding research of SSCs, their biological properties remain largely unknown which is partly due to very limited availability of these cells. Here we show that cell adhesion protein E-cadherin is a highly specific surface marker of mouse SSCs, which can be successfully used for their enrichment.