A comparative linkage map of oilseed rape and its use for QTL analysis of seed oil and erucic acid content

We have developed a new DH mapping population for oilseed rape, named TNDH, using genetically and phenotypically diverse parental lines. We used the population in the construction of a high stringency genetic linkage map, consisting of 277 loci, for use in quantitative genetic analysis. A proportion of the markers had been used previously in the construction of linkage maps for Brassica species, thus permitting the alignment of maps. The map includes 68 newly developed Sequence Tagged Site (STS) markers targeted to the homologues of defined genes of A. thaliana. The use of these markers permits the alignment of our linkage map with the A. thaliana genome sequence. An additional 74 loci (31 newly developed STS markers and 43 loci defined by SSR and RFLP markers that had previously been used in published linkage maps) were added to the map. These markers increased the resolution of alignment of the newly constructed linkage map with existing Brassica linkage maps and the A. thaliana genome sequence. We conducted field trials with the TNDH population at two sites, and over 2 years, and identified reproducible QTL for seed oil content and erucic acid content. The results provide new insights into the genetic control of seed oil and erucic acid content in oilseed rape, and demonstrate the utility of the linkage map and population.

Solid solubility limit in alloying nanoparticles

In order to gain a better thermodynamic understanding of the phase diagram of alloying nanoparticles, we establish a size-dependent solid solubility model of binary metallic systems to elucidate the anomalous solid solubility in nanometre-sized alloying particles. It is found that a diameter of 20 nm seems a threshold value of the size of alloying nanoparticles for the unusual solid solubility, i.e. the solubility is greatly promoted with decreasing grain size when the size of alloying nanoparticles is less than 20 nm. Taking the Pb-Sn system as an example, we show that the theoretical predictions are consistent with experimental data.

Novel IL-15 isoforms generated by alternative splicing are expressed in the intestinal epithelium

Previous studies have identified mRNA three isoforms encoding interleukin-15 (IL-15) that are produced through differential splicing and encode for the same mature IL-15 protein with two different signal peptides. Our analysis of mouse intestinal epithelial cells revealed two new IL-15 mRNA isoforms generated by different alternative splicing events. In one form (IL-15DeltaE6), exon 6 is absent, and in the second form the first 48 nt of exon 7 are absent (IL-15DeltaE7) through usage of an alternative 5' splicing site within exon 7. These mRNA isoforms encoded in-frame IL-15 protein variants lacking either 15aa (IL-15DeltaE6) or 16aa (IL-15DeltaE7) both utilizing the normal long signal peptide. Significant structural changes were predicted for these new IL-15 isoforms. RNAse protection assays revealed the highest expression of isoform mRNA in the intestinal epithelium and functional analysis of recombinant IL-15 isoform proteins suggested possible regulatory functions.

Genetically altered Salmonella typhimurium profoundly increases survival in nude mice with metastatic PC-3 prostate tumors

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Background: We previously published that a genetically-altered Salmonella typhimurium, expressing GFP, could completely destroy subcutaneously-implanted PC-3 tumors in nude mice when injected locally or intravenously (PNAS 102, 755–60, 2005). The bacteria are leu-arg auxotrophs which enable the bacteria to grow in PC-3 tumors but not in normal tissue. Methods: In the current study, we explore the effect of this bacteria, termed S. typhimurium A1, on metastatic PC-3 tumors orthotopically implanted in nude mice. PC-3 is a non-hormone-dependent prostate cancer. In this study, 20 mice were implanted orthotopically with PC-3 tumors expressing GFP. Approximately 2 weeks following implantation, the tumors were externally imageable. Ten of the 20 mice served as controls and followed until death without treatment. Ten mice were given the S. typhimurium A1 weekly intravenously, beginning at 2 weeks when the tumor GFP was first externally visible, and survival time was compared to the untreated mice. Ten additional non-tumor-bearing mice served as controls for the possible toxicity of S. typhimurium A1 and were also injected weekly with the bacteria intravenously. Results: Of the 10 mice with the PC-3 tumors injected weekly with S. typhimurium A1, 7 were alive and well at the time the last untreated mouse died. Currently, 4 treated mice remain alive and well 17 weeks following implantation. 3 of these 4 mice had no external fluorescence for the past 5 weeks despite discontinuing S. typhimurium A1. One mouse shows a progressive decrease in fluorescence, only a tiny spot if left. This mouse continues on S. typhimurium injection weekly. Conclusions: Injection of genetically-altered leu-arg-auxotrophic S. typhimurium into mice with metastatic PC-3 tumors has resulted in more than the tripling of lifespan of 4 of the mice. Three of the mice appear “cured” and have not external fluorescence despite discontinuing S. typhimurium treatment for the past 5 weeks. One mouse continues on weekly injections of S. typhimurium and is well with decreasing fluorescence. Since human prostate cancer eventually becomes non-androgen-dependent similar to PC-3 tumors, genetically-altered bacteria represent a novel potential treatment for this disease.

No significant financial relationships to disclose.

Sorption and complexation of Eu(III) on alumina: Effects of pH, ionic strength, humic acid and chelating resin on kinetic dissociation study

The effects of pH (pH=2-12), ionic strength (0.01-2 mol/l NaNO(3)) and humic acid on the sorption and complexation of Eu(III) on alumina were investigated by using batch techniques. The experiments were carried out at room temperature and under ambient conditions. The results indicate that the sorption of Eu(III) on alumina is strongly influenced by humic acid. The sorption of Eu(III) on alumina is significantly dependent on pH values and independent of ionic strength. The sorption of Eu(III) on alumina may be attributed to surface complexation. The species of Eu(III) on HA-alumina colloids is dominated by both HA and alumina, and the addition sequences of HA or Eu(III) to the ternary system do not influence the sorption of Eu(III) to HA-coated alumina. Kinetic dissociation of Eu(III) from bare and HA-coated alumina was also studied by using the chelating resin. The result was discussed by a pseudo-first-order kinetics model.

Effects of early feed restriction and cold temperature on lipid peroxidation, pulmonary vascular remodelling and ascites morbidity in broilers under normal and cold temperature

Two experiments were conducted to evaluate the effects of early feed restriction on lipid peroxidation, pulmonary vascular remodelling and ascites incidence in broilers under normal and low ambient temperature. In experiment 1, the restricted birds were fed 8h per day either from 7 to 14 d or from 7 to 21 d, while the controlled birds were fed ad libitum. In experiment 2, the restricted birds were fed 80 or 60% of the previous 24-h feed consumption of full-fed controls for 7 d from 7 to 14 d. On d 14, half of the birds in each treatment both in experiment 1 and experiment 2 were exposed to low ambient temperature to induce ascites. Body weight and feed conversion ratio were measured weekly. The incidences of ascites and other disease were recorded to determine ascites morbidity and total mortality. Blood samples were taken on d 14, 21, 28, 35 and 42 to measure the plasma malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). On d 42, samples were taken to determine the right/total ventricular weight ratio (RV/TV), vessel wall area/vessel total area ratio (WA/TA) and mean media thickness in pulmonary arterioles (mMTPA). Low-temperature treatment increased plasma MDA concentration. When broilers were exposed to a cool environment for 3 weeks, plasma SOD and GSH-Px activity were decreased compared with normal-temperature chicks. RV/TV, WA/TA and mMTPA on d 42 were increased in birds exposed to cold, consistent with the increased pulmonary hypertension and ascites morbidity. Early feed restriction markedly decreased plasma MDA concentration. The plasma SOD and GSH-Px activity of feed-restricted birds were markedly higher than those fed ad libitum on d 35 and d 42. All early feed restriction treatments reduced ascites morbidity and total mortality. On d 42, the RV/TV, WA/TA and mMTPA of feed-restricted broilers were lower than that of the ad libitum-fed broilers. The results suggested that early feed restriction alleviated the lipid peroxidation, promoted the activity of enzymatic antioxidant and inhibited pulmonary vascular remodelling. These changes might be associated with reduced ascites incidence.

Involvement of matrix metalloproteinase-7 in invasion-metastasis through induction of cell dissociation in pancreatic cancer

Epidermal growth factor receptor (EGFR) mediated mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway was isolated as invasion-metastasis related factor in pancreatic cancer in our previous studies. Matrix metalloproteinase-7 (MMP-7) and tight junction (TJ) proteins are indicated to be involved in cancer invasion-metastasis. To clarify the underlying mechanism of involvement of MMP-7 in cancer invasion, western blotting, invasion assay and immunohistochemistry were performed in dissociated (PC-1.0 and AsPC-1) and non-dissociated (PC-1 and Capan-2) pancreatic cancer cells, as well as pancreatic cancer tissues. Intracellular MMP-7 protein presented as pre-proenzyme and its expression was decreased by AG1478 (EGFR inhibitor) or U0126 (MEK inhibitor) treatment in pancreatic cancer cells. Activated MMP-7 protein was only detected in the medium of PC-1.0 and AsPC-1 cells, but not detected in the medium of PC-1 and Capan-2 cells. Moreover, MMP-7 treatment significant induced the dissociation of cell colonies in PC-1 and Capan-2 cells. Synchronously, TJ structure was apparently disrupted and translocation of TJ proteins to cytoplasm or extracellular medium was induced in PC-1 and Capan-2 cells. Furthermore, MMP-7 treatment markedly increased the in vitro invasion of PC-1 and Capan-2 cells. In addition, MMP-7 expression at the invasive front was obviously stronger than that at the center of pancreatic cancer tissues. Activation of MMP-7 protein is closely involved in disruption of TJ structure and consequent induction of cell dissociation as well as invasion in pancreatic cancer. EGFR mediated MEK/ERK signaling pathway is implied to be involved in regulation of MMP-7 expression in pancreatic cancer cells.

VEGF-A angiogenesis induces a stable neovasculature in adult murine brain

Angiogenesis is a critical component of stroke, head injury, cerebral vascular malformation development, and brain tumor growth. An understanding of the mechanisms of adult cerebral angiogenesis is fundamental to therapeutic vessel modulation for these diseases. To study angiogenesis in the central nervous system, we injected an adenoviral vector engineered to express vascular endothelial growth factor (VEGF-A164) into adult murine striatum. Vector-infected astrocytes expressed VEGF-A164 resulting in vascular permeability, hemorrhage, and the formation of greatly enlarged "mother" vessels. Subsequently, endothelial cells and pericytes lining mother vessels proliferated and assembled into glomeruloid bodies, complex cellular arrays interspersed by small vessel lumens. As VEGF-A164 expression declined, glomeruloid bodies involuted through apoptotic processes to engender numerous small daughter vessels. Characterized by modestly enlarged lumens with prominent pericyte coverage, daughter vessels were distributed with a density greater than normal cerebral vessels. Daughter vessels remained stable and patent to 16 months and represented the final stage of VEGF-A-induced cerebral angiogenesis. Together, these findings provide a mechanistic understanding of angiogenesis in cerebral disease processes. Furthermore, the long-term stability of daughter vessels in the absence of exogenous VEGF-A164 expression suggests that VEGF-A may enable therapeutic angiogenesis in brain.

Identification of genes related to invasion and metastasis in pancreatic cancer by cDNA representational difference analysis

The difference in gene expression between the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and metastatic cell line PC-1 both derived from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine (BOP) in Syrian golden hamster was examined using the Representational Difference Analysis (RDA) method. Within 8 clones (cDNA fragments) successfully isolated after subtraction hybridization of PC-1 cDNA from PC-1.0, 5 clones were shown to be specific or highly expressed in PC-1.0 as confirmed by RT-PCR. Among these 5 clones, two known genes, MAP kinase kinase 2 (MKK2) and phosphatidylinositol 4-kinase (PI4K230) were detected by gene sequencing. The specific expressions of MKK2 and PI4K230 in the highly invasive and metastatic cell line PC-1.0 were confirmed by RT-PCR and Northern blotting. By adding the CM of PC1.0 which included the cancer cell dissociation factor (DF), PC-1 cells began to dissociate and migrate from the colonies, and in addition the expression of MKK2 was found to be induced. On the other hand, the expression of PI4K230 was not induced in PC-1 cells by adding the CM of PC-1.0. Interestingly, in PC-1.0 the expression of PI4K230 was completely abolished and apoptosis induced by the PI3K inhibitor wortmannin. These results suggest that both MKK2 and PI4K230 are factors of a signal transduction pathway that might play an important role related to invasion and metastasis through the induction of cell motility and/or the inhibition of apoptosis.

[Changes of serum cardiac troponin T in patients undergoing cardiac surgery]

We detected the changes of serum cardiac troponin T(cTn T) content and serum cardiac enzyme activities in 15 patients with cardiopulmonary bypass during cardiac operation. The central venous blood samples were collected to measure the serum concentration of cTn T by enzyme immunoassay methods and activities of lactate dehydrogenase(LDH), creatine kinase(CK), and creatine kinase isoenzyme(CK-MB) by biochemical methods. The content of cTn T and activities of LDH, CK, and CK-MB increased significantly after cardiac surgery. There was positive correlation between cTn T and aortic cross clamping time (r = 0.6014, P < 0.05), but there was no correlation between CK-MB and aortic cross clamping time (r = 0.4712, P > 0.05). We conclude that serum cTn T and CK-MB can monitor cardiac ischemic reperfusion injury and can evaluate myocardial protection methods during cardiac operation, but cTn T is better than CK-MB.

[Changes in lipoprotein (a) and the relation between lipoprotein (a) and endothelin in patients during upper abdominal surgery]

OBJECTIVE

We observed the changes in both serum lipoprotein(a) [Lp(a)] and plasma endothelin (ET) during upper abdominal surgery under intravenous combined with inhalation anesthesia and we also analyzed their correlativity.

METHODS

Fifteen patients, scheduled for upper abdominal surgery, were anesthetized with total does of fentanal 8-12 micrograms.kg-1 and inhalation of 1-2 MAC enflurane. Serum Lp(a) and plasma ET at pre-anesthesia, pre-operation, 1 h from the start of operation and 30 min after operation were determined.

RESULTS

The average concentrations of Lp(a) and ET were increased at 1 h from the start of operation compared with pre-anesthesia, but had no statistical significance. Lp(a) and ET were significantly higher at 30 min after operation than pre-anesthesia(P < 0.05).

CONCLUSION

Lp(a) and ET have a close relation in advancing cardio-cerebral blood vessel diseases.

[A model of closed epidural balloon inflation brain injury in rats]

OBJECTIVES

To establish an animal model of closed brain epidural occupancy trauma in rats.

METHODS

Sixty-eight Wistar rats were randomly divided into 7 groups: normal control group(Group A), sham-operated group(Group B), and 5 experimental groups. The last ones included: Group C in which water was injected 0.05 ml into balloon and kept for 1 hour; Group D injected 0.05 ml and kept for 3 hours; Group E injected 0.1 ml and kept for 1 hour; Group F injected 0.1 ml and kept for 2 hours. Group B, C, D were kept maintaining and observing for two days after operation, respectively. Group E was divided into EI (maintaining for two days) and EII (for three days).

RESULTS

Of all the experimental groups, the mortality rate during acute phase was 100% in Group F, 28% in Group E, 50% in Group D, and 0% in Group C. Four rats died during the raising-up period in Group E. Both ICP and cerebral water content were increased in 46 survived rats, and nerve functions were damaged in all the experimental groups. Pathologic changes read as follows: Hemorrhage was found in damage-area; injury and dead cells were seen in compressed region. These changes became worse with time prolonged and injury degree developed.

CONCLUSIONS

The method is simple, reproducible and economical, well showing the pathological classification of epidural occupancy trauma.

[Effect of desflurane on quantitative electroencephalogram and hemodynamics]

To evaluate the feasibility of monitoring depth of desflurane anesthesia by quantitative electroencephalogram(QEEG) and hemodynamics, eight ASA I-II patients were studied. Anesthesia was induced by propofol and vecuronium, after tracheal intubation and the lungs were ventilated with desflurane in oxygen. The results showed that desflurane significantly reduced bispectral index(BI), 95% spectral edge frequency(SEF) and median frequency(MF) in a negative linear dose-related manner. When the end-tidal desflurane concentration reached 1.5 MAC, mean artery pressure(MAP) was decreased significantly, and heart rate(HR) increased by 14.5% (but there was no statistic significance), compared with pre-anesthesia. The results suggest that QEEG can be used to monitor depth of desflurane anesthesia, but MAP and HR are not the ideal monitoring indices during desflurane anesthesia.

Identification of cis-DNA regions controlling Bmp4 expression during tooth morphogenesis in vivo

Epithelial-mesenchymal interactions are required for tooth formation. Bone morphogenetic protein 4 (Bmp4) is a crucial signaling molecule during this process. For better understanding of the role of the Bmp4 gene during tooth development, we studied the mechanisms that control its temporal and spatial expression during development. Using a transgenic approach, we determined that the domains which controlled Bmp4 expression in epithelium-derived ameloblasts were located in the region between 0.26 kb and 1.1 kb of the murine Bmp4 promoter. In contrast, the domains controlling Bmp4 expression in mesenchyme-derived odontoblasts and pulp cells existed in other regions of the Bmp4 gene. We have also demonstrated that the domains controlling Bmp4 expression in primordial tooth cells differ from those controlling Bmp4 expression in mature tooth tissues. The determination of unique domains by controlling the expression of the Bmp4 gene suggests that different transcriptional factors regulate the Bmp4 level at different stages during tooth morphogenesis.