Complexity and diversity of F8 genetic variations in the 1000 genomes

BACKGROUND

Hemophilia A (HA) is an X-linked bleeding disorder caused by deleterious mutations in the coagulation factor VIII gene (F8). To date, F8 mutations have been documented predominantly in European subjects and in American subjects of European descent. Information on F8 variants in individuals of more diverse ethnic backgrounds is limited.

OBJECTIVES

To discover novel and rare F8 variants, and to characterize F8 variants in diverse population backgrounds.

PATIENTS/METHODS

We analyzed 2535 subjects, including 26 different ethnicities, whose data were available from the 1000 Genomes Project (1000G) phase 3 dataset, for F8 variants and their potential functional impact.

RESULTS

We identified 3030 single nucleotide variants, 31 short deletions and insertions (Indels) and a large, 497 kb, deletion. Among all variants, 86.4% were rare variants and 55.6% were novel. Eighteen variants previously associated with HA were found in our study. Most of these 'HA variants' were ethnic-specific with low allele frequency; however, one variant (p.M2257V) was present in 27% of African subjects. The p.E132D, p.T281A, p.A303V and p.D422H 'HA variants' were identified only in males. Twelve novel missense variants were predicted to be deleterious. The large deletion was discovered in eight female subjects without affecting F8 transcription and the transcription of genes on the X chromosome.

CONCLUSION

Characterizing F8 in the 1000G project highlighted the complexity of F8 variants and the importance of interrogating genetic variants on multiple ethnic backgrounds for associations with bleeding and thrombosis. The haplotype analysis and the orientation of duplicons that flank the large deletion suggested that the deletion was recurrent and originated by homologous recombination.

Effect of low temperatures on BAX and BCL2 proteins in rats with spinal cord ischemia reperfusion injury

We evaluated changes in BAX and BCL2 expression levels after spinal cord ischemia/reperfusion injury (SCII) and hypothermia during operations in rats. Eighty rats were divided into four groups: Group A (N = 20, 18°C); Group B (N = 20, 28°C); Group C (N = 20, room temperature); and Group D (N = 20, sham operation control). Spinal cord ischemia was induced for 90 min. Hypothermia was induced 15 min before, and maintained during ischemia, followed by heating to normothermia for 30 min after reperfusion. Motor function of the lower limbs was evaluated according to the Tarlov score at 72 and 168 h. For each rat, spinal cord samples were taken at 6, 24, 72 h, and 1 week to evaluate the histopathological changes, neuronal apoptosis, and BAX and BCL2 expression levels. Compared with normothermia, hypothermia significantly improved hind limb function; Group B achieved a higher score than Group A. Group D showed no neurologic deficiency, while the other groups showed various degrees. Group C exhibited greater neuronal apoptosis, higher BAX expression, but lower BCL2 expression than the other groups. Compared with Group A, BAX was expressed less and BCL2 more in Group B, and there was less apoptosis in Group B. Hypothermia preserves hind limb motor function and reduces neuronal death, thereby protecting rats from SCII. The spinal cord may be protected from SCII by inhibition of BAX and activation of BCL2. However, deep hypothermia may inhibit the expression of BCL2, resulting in a worse outcome than mild hypothermia.

Sex- and afferent-specific differences in histamine receptor expression in vagal afferents of rats: A potential mechanism for sexual dimorphism in prevalence and severity of asthma

The incidence of asthma is more common in boys than in girls during the childhood, and more common in premenopausal female than age-matched males. Our previous study demonstrated a gender difference in histamine-mediated neuroexcitability in nodose ganglia neurons (NGNs), highlighting a possibility of histamine-mediated gender difference in asthma via visceral afferent function. In the present study, we aimed to explore the gender difference in expression profiles of histamine receptors (HRs) in nodose ganglia (NG) and individual identified NGNs to provide deeper insights into the mechanisms involved in sexual dimorphism of asthma. Western-blot and SYBR green RT-PCR showed that H2R and H3R were highly expressed in NG of females compared with males and downregulated in ovariectomized females. H1R was equally expressed in NG of both sexes and not altered by ovariectomy. Furthermore, this highly expressive H2R and H3R were distributed in both myelinated and unmyelinated NGNs isolated from adult female rats by immunofluorescence and single-cell RT-PCR. H3R widely distributed in all tested neuron subtypes and its expression did not show significant difference among neuron subtypes. H2R was widely and highly expressed in low-threshold and sex-specific subpopulation of myelinated Ah-types compared with myelinated A- and unmyelinated C-type NGNs. Unexpectedly, weak expression of H1R was detected in both myelinated and unmyelinated NGNs by immunofluorescence, which was further confirmed by single-cell RT-PCR. Our results suggest that the sexual dimorphism in the expression of H2R and H3R in vagal afferents very likely contributes, at least partially, to the gender difference in prevalence and severity of asthma.

The temporal bone microdissection of miniature pigs as a useful large animal model for otologic research

CONCLUSION

Compared with traditional animal models, the miniature pig may be a better model for biomedical research because its morphology has many similarities with that of humans.

OBJECTIVE

To investigate the suitability of the miniature pig as an animal model for otological research as regards morphology.

METHODS

Microdissection of the temporal bone of 10 miniature pigs was performed and recorded on photographs.

RESULTS

The morphology and measurements of the external, middle, and inner ear, and the lateral recess of the miniature pigs were completed by microdissection. The temporal bone structures, including the external, middle, inner ear, and the lateral recess, were similar in the miniature pig and humans.

Involvement of CRH and hCG in the induction of aromatase by cortisol in human placental syncytiotrophoblasts

INTRODUCTION

Increased estrogen production in placenta towards the end of gestation plays a pivotal role in the onset of human labor. Estrogen transforms myometrium from a quiescent to a contractile status. Glucocorticoids have been shown to induce estrogen production through the transcription factor specificity protein 1 (Sp1)-mediated induction of aromatase transcription upon elevation of cyclic adenosine mono-phosphate (cAMP) level in human placental syncytiotrophoblasts. However, it is unclear how glucocorticoids activate cAMP pathway thereby inducing aromatase expression in human placental syncytiotrophoblasts.

MATERIAL AND METHODS

We investigated this issue in cultured primary human placental syncytiotrophoblasts prepared from placentas collected at term without labor.

RESULTS

We demonstrated that cortisol (0.01-1 μM) dose-dependently increased corticotropin-releasing hormone (CRH) and human chorionic gonadotropin (hCG) α/β subunit expression and their production in the syncytiotrophoblasts. The induction of intracellular cAMP level, Sp1 expression, Sp1 enrichment at the aromatase promoter as well as aromatase expression by cortisol could be partially attenuated by either hCG antibody (1:100) or CRH receptor antagonist α-helical-CRH (1 μM), and further attenuated by combination of hCG antibody and α-helical-CRH.

CONCLUSIONS

Cortisol increases aromatase expression via induction of CRH and hCG production and subsequent elevation of cAMP level and enrichment of Sp1 at the aromatase promoter in human placental syncytiotrophoblasts. These findings may account for the parallel increases of cortisol and estrogen production prior to the onset of parturition.

Migration and leaching risk of extraneous antimony in three representative soils of China: lysimeter and batch experiments

Antimony (Sb) distribution, solubility and mobility onto natural soils of China were studied in lysimeter and batch experiments as a function of physicochemical properties of the soil. An outdoor lysimeter experiment investigated the leaching and migration of Sb in the soils with Sb-polluted topsoil and unpolluted subsoil over a 5month period. Soil solutions were collected by suction cups installed at different depth of lysimeters, and leachates were regularly collected and analyzed for Sb concentrations. The majority of the added Sb was retained in the topsoil layers, but small portions were moved to the sub-layers. Sb concentrations in the soil solutions and leachates ranged from 0-755.5 (6.38±54 on average) μg l(-1) and 0-0.45 (smaller than the detection limit) μg l(-1) respectively, indicating the low solubility of Sb in the soils. Batch experiments were performed in order to determine the sorption capacity and the partition coefficient (Kd). Freundlich isotherm described properly the equilibrium experimental data and results show that the Kd values for Primosol, Isohumosol, Ferrosol equal to 22.5, 87.8, 704 L kg(-1), respectively. These results showed the strong capacity of the soils to retain Sb, and prevent it being leached down the profile. The mobilizable Sb was in the order: Primosol>Isohumosol>Ferrosol. Sb migration in the soils was mainly associated with the exchangeable, carbonate-bound, and metal-organic complex-bound fractions. Health risk assessment indicates that Sb leaching from Ferrosol will not harm to human health through groundwater under the test conditions, while it has certain health risks from the Isohumosol and Primosol.

Plasmon resonances and strong electric field enhancements in side-by-side tangent nanospheroid homodimers

The plasmon resonance and electric field enhancement in a side-by-side tangent nanospheroid homodimer (TNSHD) have been investigated theoretically by using DDA and FDTD methods, respectively. The simulation results indicate that this side-by-side TNSHD has its novel optical properties. We find that the plasmon resonance with a distinct Fano lineshape can be achieved and the electric field intensity can be enhanced strongly. The tunability of the Fano resonance could provide important applications in biosensing. The obtained electric field enhancement might open a promising pathway for surface-enhanced Raman scattering (SERS) and light trapping in solar cells.

The diagnosis and surgical treatment of occult otogenic CSF leakage

CONCLUSIONS

The diagnosis of occult otogenic cerebrospinal fluid (CSF) leakage is challenging and it can easily be misdiagnosed. Some characteristics of clinical presentation can supply important clues and confirmed diagnosis should be obtained according to these clues and suitable imaging studies before meningitis develops. Different surgical techniques should be adopted to treat the CSF leakage according to different leakage etiologies, and good results can be obtained.

OBJECTIVE

The aim of the study was to evaluate the diagnosis and surgical treatment of occult otogenic CSF leakage, including the characteristics of clinical presentation, imaging studies, and operation methods in order to decrease the rate of misdiagnosis and obtain a good curative effect.

METHODS

We performed a retrospective review of 11 cases of CSF leakage that were all misdiagnosed and accompanied by meningitis, operated in our department from 2007 to 2012 after a mean follow-up of 3 years. In this context, the characteristics of clinical presentation, imaging studies, and management of CSF leakage were studied.

RESULTS

The CSF leakage had arisen traumatically (n = 9) or congenitally (n = 2). The medical history and special clinical presentation such as repeated otorrhea or rhinorrhea, fever, headache, and unilateral deafness can supply important diagnostic clues. Imaging studies including high-resolution noncontrast CT (HRCT), CT cisternography, and magnetic resonance imaging (MRI) are very important diagnostic methods. The surgical repairs were performed via a transmastoid approach (n = 8), packing the vestibule (n = 1) or a translabyrithine approach (n = 2). Recurrent leakage did not occur.

A new inducible expression system in a transformed green alga, Chlorella vulgaris

Genetic transformation is useful for basic research and applied biotechnology. However, genetic transformation of microalgae is usually quite difficult due to the technical limitations of existing methods. We cloned the promoter and terminator of the nitrate reductase gene from the microalga Phaeodactylum tricornutum and used them for optimization of a transformation system of the microalga Chlorella vulgaris. This species has been used for food production and is a promising candidate as a bioreactor for large-scale production of value-added proteins. A construct was made containing the CAT (chloramphenicol acetyltransferase) reporter gene driven by the nitrate reductase promoter. This construct was transferred into the C. vulgaris genome by electroporation. Expression of CAT in transgenic Chlorella conferred resistance to the antibiotic chloramphenicol and enabled growth in selective media. Overall efficiency for the transformation was estimated to be approximately 0.03%, which is relatively high compared with other available Chlorella transformation systems. Expression of CAT was induced in the presence of nitrate and inhibited in the presence of ammonium as a sole nitrogen source. This study presented an inducible recombinant gene expression system, also providing more gene regulation elements with potential for biotechnological applications.

The Sp1 transcription factor is crucial for the expression of 11beta-hydroxysteroid dehydrogenase type 2 in human placental trophoblasts

CONTEXT

Overexposure of the fetus to glucocorticoids early in gestation is detrimental to fetal development. Glucocorticoid concentrations in the fetal circulation are kept low by 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2, encoded by HSD11B2) in the placental syncytiotrophoblasts. However, cytotrophoblasts, the progenitors of syncytiotrophoblasts, express low levels of 11β-HSD2. Here we studied the molecular mechanisms underlying 11β-HSD2 induction upon syncytialization.

METHODS

Freshly isolated human term placental cytotrophoblasts and in vitro differentiated syncytiotrophoblasts were examined to determine the methylation status of HSD11B2 promoter. The transcription factor responsible for 11β-HSD2 induction was identified by observing its expression upon syncytialization, the effect of its attenuation, and its binding to the HSD11B2 promoter.

RESULTS

11β-HSD2 expression was markedly increased upon syncytialization in vitro. No methylation differences of HSD11B2 promoter were found between cytotrophoblasts and syncytiotrophoblasts. Expression of the transcription factor Sp1 was markedly induced during syncytialization and further increased by activation of the cAMP pathway, which correlated with 11β-HSD2 expression. Importantly, small interfering RNA-mediated knockdown of Sp1 expression or inhibition of Sp1 activity with mithramycin A markedly attenuated not only basal but also cAMP pathway-stimulated expression of 11β-HSD2 in the syncytiotrophoblasts. Stimulation of the cAMP pathway also increased the binding of Sp1 and RNA polymerase II to HSD11B promoter in syncytiotrophoblasts. Concomitantly, acetylation at histone H3K9 was increased whereas methylation at histone H3K9 was decreased.

CONCLUSIONS

11β-HSD2 induction upon syncytialization is at least in part due to the increased expression of Sp1 upon activation of the cAMP pathway rather than the differential methylation of the HSD11B2 promoter.

Cross talk between cAMP and p38 MAPK pathways in the induction of leptin by hCG in human placental syncytiotrophoblasts

Leptin produced by the placental syncytiotrophoblasts participates in a number of processes in pregnancy including implantation, proliferation of the cytotrophoblasts, and nutrient transfer across the placenta. Despite the functional significance of leptin in pregnancy, the regulation of leptin synthesis is poorly understood in human placental syncytiotrophoblasts. In this study, we investigated the role of endogenous human chorionic gonadotropin (hCG) in the regulation of leptin production as well as the underlying mechanism involving the cross talk between cAMP and p38 mitogen-activated protein kinase (MAPK) pathways. We found that neutralization of endogenous hCG with its antibody dose dependently decreased leptin mRNA level and secretion, whereas exogenous hCG increased leptin mRNA level and secretion. Activation of the cAMP pathway with dibutyryl cAMP (db cAMP) or forskolin recapitulated the stimulatory effect of hCG on leptin expression. Inhibition of protein kinase A with H89 not only reduced the basal leptin expression but also attenuated the induced leptin expression by hCG. Treatment of the syncytiotrophoblasts with db cAMP and hCG phosphorylated p38 MAPK. Inhibition of p38 MAPK with SB203580 not only reduced the basal leptin production but also attenuated the leptin-induced production by both hCG and db cAMP. These data suggest that endogenous hCG plays a significant role in maintaining leptin production in human placental syncytiotrophoblasts, and this effect involves a cross talk between cAMP and p38 MAPK pathways.

Role of human chorionic gonadotropin in maintaining 11beta-hydroxysteroid dehydrogenase type 2 expression in human placental syncytiotrophoblasts

Proper glucocorticoid exposure in utero is vital for normal fetal organ maturation, but excess glucocorticoids are detrimental to fetal growth and can even predispose the individuals to the high risk of having certain diseases in adulthood. The fetus is protected from 10 times higher maternal glucocorticoid levels by the placental enzyme 11beta-hydroxysteroid dehydrogenase 2 (11beta-HSD2), which converts biologically active cortisol to inactive cortisone. Thus it is of primary importance to understand how this enzyme is regulated. Activation of cAMP/PKA pathway is known to upregulate 11beta-HSD2 expression in placental syncytiotrophoblasts, however the endogenous hormones utilizing this pathway remain largely unknown. By using cultured human placental syncytiotrophoblasts, we demonstrated that inhibition of protein kinase A with H89 attenuated 11beta-HSD2 expression in the syncytiotrophoblasts, suggesting endogenous factors from the syncytiotrophoblasts using this pathway to maintain 11beta-HSD2 expression in the syncytiotrophoblasts. Neutralization of human chorionic gonadotropin (hCG) secreted by the syncytiotrophoblasts with hCG antibody decreased 11beta-HSD2 promoter activity, mRNA and protein expression as well as intracellular cAMP level, while treatment of the syncytiotrophoblasts with exogenous hCG increased 11beta-HSD2 expression, which was attenuated by H89. Furthermore, we found that cortisol increased both hCG expression and secretion. The up-regulation of 11beta-HSD2 expression by cortisol was significantly attenuated by co-treatment with hCG antibody or H89 in the syncytiotrophoblasts. In conclusion, hCG is an important paracrine or autocrine hormone maintaining 11beta-HSD2 expression and the up-regulation of 11beta-HSD2 expression by cortisol may be mediated in part by hCG in the syncytiotrophoblasts.

Paradoxical stimulation of cyclooxygenase-2 expression by glucocorticoids via a cyclic AMP response element in human amnion fibroblasts

Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is one of the major events leading to parturition. In marked contrast to its well-described antiinflammatory effect, glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression in human amnion fibroblasts. The mechanisms underlying this paradoxical induction of COX-2 by glucocorticoids have not been resolved. Using cultured human amnion fibroblasts, we found that the induction of COX-2 mRNA expression by cortisol was a glucocorticoid receptor (GR)-dependent process requiring ongoing transcription. Upon transfection of a COX-2 promoter-driven reporter gene into the amnion fibroblasts, cortisol stimulated the COX-2 promoter activity. This was abolished by mutagenesis of a cAMP response element (CRE) at -53 to approximately -59bp as well as by cotransfection of a plasmid expressing dominant-negative CRE-binding protein (CREB). The phosphorylation level of CREB-1 was significantly increased by cortisol treatment of the amnion fibroblasts, whereas the effect was attenuated either by the protein kinase A inhibitor H89 or the p38 -MAPK inhibitor SB203580. The induction of the COX-2 promoter activity and the phosphorylation of CREB-1 were also blocked by the GR antagonist RU486. Chromatin immunoprecipitation (ChIP) assay revealed that the binding of CREB-1 to the CRE of the COX-2 promoter was increased by cortisol treatment of the amnion fibroblasts. In conclusion, cortisol, via binding to GR, stimulated COX-2 expression by increasing phosphorylated CREB-1 binding to the CRE of the COX-2 gene. Cortisol may phosphorylate CREB-1 by activating either protein kinase A or p38-MAPK in the amnion fibroblasts.

QTL mapping of seed coat color for yellow seeded Brassica napus

The development of yellow-seeded varieties of Brassica napus for improving the oilseed quality characteristics of lower fiber content and higher protein and oil content has been a major focus of breeding researches worldwide in recent years. With the black-seeded 'Youyan 2' as male and the yellow-seeded GH06 as female parents respectively, F2 population of 132 individuals were obtained. A linkage map was constructed with 164 markers including 125 AFLP, 37 SSR, 1 RAPD and 1 SCAR markers distributed over 19 linkage groups covering approximately 2 549.8 cM with an average spacing of 15.55 cM. Two loci located on the 5th and 19th group were detected for the trait of seed coat color based on the linkage group using multiple interval mapping method and explained 46% and 30.9% of the phenotypic variation, respectively.

[QTL for seed germination rate and related physiological traits of Brassica napus L]

One hundred and eighty-three recombinant inbred lines from the cross between GH06 and P174 were used for genetic analysis of seed germination rate and physiological trait analysis of Brassica napus L. Composite interval mapping (CIM) was applied to identify QTL associated with seed germination rate (GR) of the seeds that stored for two years (STY), one year (SOY), and fresh seeds (FS), respectively. The activity of lipases, seed conductivity, reducing sugar content, total sugar content, and root vitality of STY and FS were investigated. The QTL for seed GR of various stored seeds were different. Three QTLs for STY were detected on the linkage group (LG) 9, 14, and 17. Two QTL for SOY were mined on LG 5 and 9. Two QTLs for FS were detected on LG 4 and 18. The germination rate of seeds from three years was significantly different, and the QTL of GR was not identical, which indicated that the seed germination was controlled by many loci. Furthermore, the seed germination rate was negatively correlated with seed conductivity, which means that measurement of seed conductivity can be used to estimate GR, and the study of conductivity is important for GR research.

Cloning and characterization of phosphorus starvation inducible Brassica napus PURPLE ACID PHOSPHATASE 12 gene family, and imprinting of a recently evolved MITE-minisatellite twin structure

Purple acid phosphatase (PAP) is important for phosphorus assimilation and in planta redistribution. In this study, seven Brassica napus PAP12 (BnPAP12) genes orthologous to Arabidopsis thaliana PAP12 (AtPAP12) are isolated and characterized. NCBI BLASTs, multi-alignments, conserved domain prediction, and featured motif/residue characterization indicate that all BnPAP12 members encode dimeric high molecular weight plant PAPs. BnPAP12-1, BnPAP12-2, BnPAP12-3 and BnPAP12-7 (Group I) have six introns and encode 469-aa polypeptides structurally comparable to AtPAP12. BnPAP12-4 and BnPAP12-6 (Group II) have seven introns and encode 526-aa PAP12s. Encoding a 475-aa polypeptide, BnPAP12-5 (Group III) is evolved from a chimera of 5' part of Group I and 3' part of Group II. Sequence characterization and Southern detection suggest that there are about five BnPAP12 alleles. Homoeologous non-allelic fragment exchanges exist among BnPAP12 genes. BnPAP12-4 and BnPAP12-6 are imprinted with a Tourist-like miniature inverted-repeat transposable element (MITE) which is tightly associated with a novel minisatellite composed of four 36-bp tandem repeats. Existing solely in B. rapa/oleracea lineage, this recently evolved MITE-minisatellite twin structure does not impair transcription and coding capacity of the imprinted genes, and could be used to identify close relatives of B. rapa/oleracea lineage within Brassica. It is also useful for studying MITE activities especially possible involvement in minisatellite formation and gene structure evolution. BnPAP12-6 is silent in transcription. All other BnPAP12 genes basically imitate AtPAP12 in tissue specificity and Pi-starvation induced expression pattern, but divergence and complementation are distinct among them. Alternative polyadenylation and intron retention also exist in BnPAP12 mRNAs.

Localization of QTLs for seed color using recombinant inbred lines of Brassica napus in different environments

Yellow seed is one of the most important traits of Brassica napus L. Efficient selection of the yellow-seed trait is one of the most important objectives in oilseed rape breeding. Two recombinant inbred line (RIL) populations (RIL-1 and RIL-2) were analyzed for 2 years at 2 locations. Four hundred and twenty SSR, RAPD, and SRAP marker loci covering 1744 cM were mapped in 26 linkage groups of RIL-1, while 265 loci covering 1135 cM were mapped in 20 linkage groups of RIL-2. A total of 19 QTLs were detected in the 2 populations. A major QTL was detected adjacent to the same marker (EM11ME20/200) in both maps in both years. This major QTL could explain 53.71%, 39.34%, 42.42%, 30.18%, 24.86%, and 15.08% of phenotypic variation in 6 combinations (location x year x population). BLASTn analysis of the sequences of the markers flanking the major QTL revealed that the homologous region corresponding to this major QTL was anchored between genes At5g44440 and At5g49640 of Arabidopsis thaliana chromosome 5 (At C5). Based on comparative genomic analysis, the bifunctional gene TT10 is nearest to the homologue of EM11ME20/200 on At C5 and can be considered an important candidate gene for the major QTL identified here. Besides providing an effective strategy for marker-assisted selection of the yellow-seed trait in B. napus, our results also provide important clues for cloning of the candidate gene corresponding to this major QTL.

Molecular cloning of two genes encoding cinnamate 4-hydroxylase (C4H) from oilseed rape (Brassica napus)

Cinnamate 4-hydroxylase (C4H) is a key enzyme of phenylpropanoid pathway, which synthesizes numerous secondary metabolites to participate in development and adaption. Two C4H isoforms, the 2192-bp BnC4H-1 and 2108-bp BnC4H-2, were cloned from oilseed rape (Brassica napus). They both have two introns and a 1518-bp open reading frame encoding a 505-amino-acid polypeptide. BnC4H-1 is 57.73 kDa with an isoelectric point of 9.11, while 57.75 kDa and 9.13 for BnC4H-2. They share only 80.6% identities on nucleotide level but 96.6% identities and 98.4% positives on protein level. Showing highest homologies to Arabidopsis thaliana C4H, they possess a conserved p450 domain and all P450-featured motifs, and are identical to typical C4Hs at substrate-recognition sites and active site residues. They are most probably associated with endoplasmic reticulum by one or both of the N- and C-terminal transmembrane helices. Phosphorylation may be a necessary post-translational modification. Their secondary structures are dominated by alpha helices and random coils. Most helices locate in the central region, while extended strands mainly distribute before and after this region. Southern blot indicated about 9 or more C4H paralogs in B. napus. In hypocotyl, cotyledon, stem, flower, bud, young- and middle-stage seed, they are co-dominantly expressed. In root and old seed, BnC4H-2 is dominant over BnC4H-1, with a reverse trend in leaf and pericarp. Paralogous C4H numbers in Brassicaceae genomes and possible roles of conserved motifs in 5' UTR and the 2nd intron are discussed.

Cloning and molecular characterization of a functional flavonoid 3'-hydroxylase gene from Brassica napus

A flavonoid 3'-hydroxylase (F3'H) gene, denoted BnF3'H-1, was cloned from oilseed rape (Brassica napus). The gene of 3038 base pairs (bp) contains 3 introns. The complementary DNA (cDNA) consists of 1820bp and has an open reading frame of 1536bp encoding a polypeptide of 511 amino acids with a molecular weight of 56.62kDa and an isoelectric point of 7.08. BnF3'H-1 shows high homology to known F3'H genes, especially F3'H from Arabidopsis thaliana. Untranslated regions (UTRs) may play important roles in regulating the expression of BnF3'H-1. Besides containing a Kozak sequence, the first 77-bp region is C-rich but G-poor, and the 26-bp 5'-UTR contains 3 sites of ACCACT-like sequences. Alternative polyadenylation in the 3'-UTR is adopted by this gene to generate heterogeneous transcripts. Conserved domain search and motif characterization identified BnF3'H-1 as a cytochrome P450. All F3'H-featured motifs, VVVAAS, GGEK and VDVKG, are unchanged in BnF3'H-1. The N-terminal signal peptide/anchor and 3 transmembrane helices were predicted in BnF3'H-1, and its subcellular localization is most probably at the endoplasmic reticulum. Since 16 phosphorylation sites could be predicted, phosphorylation may be a necessary post-translational modification of BnF3'H-1. The secondary structure is dominated by alpha-helices and random coils. Most helices are located in the middle region, while extended strands mainly intersperse in terminal regions. DNA gel blot analysis indicated that 2 different F3'H genes might exist in B. napus. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and RNA gel blot analysis showed that flowers have the highest F3'H expression, followed by pericarp and seed, and lower levels in some other organs. This species-featured expression pattern is in obedience to multiple functional roles that F3'H gene(s) play(s) in various organs of B. napus. The BnF3'H-1 coding region was expressed in Escherichia coli, and enzyme activity of the His-tagged protein was demonstrated by monitoring the conversion of the substrate naringenin using high-performance liquid chromatography (HPLC), suggesting that BnF3'H-1 is catalytically functional. RT-PCR analysis suggests that transcription level of the F3'H gene(s) is not the reason for the different seed colorations found in near-isogenic lines (black-seeded L1 and yellow-seeded L2) of B. napus.

Molecular cloning of Brassica napus TRANSPARENT TESTA 2 gene family encoding potential MYB regulatory proteins of proanthocyanidin biosynthesis

Three members of Brassica napus TRANSPARENT TESTA 2 (BnTT2) gene family encoding potential R2R3-MYB regulatory proteins of proanthocyanidin biosynthesis were isolated. BnTT2-1, BnTT2-2, and BnTT2-3 are 1102 bp with two introns, and have a 938-bp full-length cDNA with a 260 amino acid open reading frame. They share 98.2-99.3% nucleotide and 96.5-98.5% amino acid identities to each other, and are orthologous to Arabidopsis thaliana TT2 (AtTT2) with 74.1-74.8% nucleotide and 71.1-71.8% amino acid identities. An mRNA type of BnTT2-2 was found to contain unspliced intron 2 and encode a premature protein. They all have an alternative polyadenylation site. BnTT2-1 and BnTT2-3 also have an alternative transcription initiation site. Aligned with AtTT2, their 5' untranslated regions (UTRs) are astonishingly conserved, and two conserved regions were also found in their 3' UTRs. Oligonucleotide deletion leads to double-start codons of them. Resembling AtTT2, BnTT2 proteins are nuclear-located R2R3-MYB proteins containing predicted DNA-binding sites, bHLH interaction residues, and transcription activation domains. Southern blot indicated that there might be three BnTT2 members in B. napus, lower than triplication-based prediction. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed that the expression of BnTT2-2 is mostly like AtTT2 with intensive expression in young seeds, but it is also expressed in root in which AtTT2 has no expression. BnTT2-1 shows lower tissue specificity and transcription levels, whereas BnTT2-3 is the lowest. Comparative cloning and RT-PCR indicated that seed color near-isogenic lines L1 and L2 have equivalent BnTT2 genes, and the yellow seed color in L2 might be caused by locus/loci other than BnTT2. Our results lay the basis for further investigating the regulatory mechanism of BnTT2 genes in flavonoid pathway and for transgenic creation of novel yellow-seeded B. napus stocks.

Carbon paste electrode for trace zirconium(IV) determination by adsorption voltammetry

A very sensitive and selective procedure was developed for trace measurement of zirconium based on the cathodic adsorptive stripping voltammetry of the zirconium-alizarin red S(ARS) complex at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the zirconium-ARS complex were recorded by a model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). Optimal analytical conditions were found to be: an acetic acid (0.1 mol l(-1))-potassium biphthalate (0.08 mol l(-1)) buffer solution (pH 4.8) containing 4.0 x 10-6 mol l(-1) ARS; accumulation potential, 0.0 V; accumulation time, 180 or 90 s; rest time, 10 s; scan rate, 250 mV s(-1). The results showed that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.51 V, corresponding to the reduction of ARS in the complex at the electrode. The detection limit was found to be 1.0 x 10(-10) mol l(-1) (S/N = 3) for 240 s accumulation. The linear range was 2.0 x 10(-10)-4.0 x 10(-7) mol l(-1). The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.

Fatty acid synthase (FAS) expression in human breast cancer cell culture supernatants and in breast cancer patients

Fatty acid synthase (FAS) is selectively expressed in certain human cancers, including carcinoma of the breast, prostate, colon, ovary, and endometrium, compared to normal human tissues and therefore is a putative tumor marker. In this study, we found FAS concentrations were elevated in cell culture supernatants during cell growth in two human breast cancer cell lines but not other cancer cell lines. A quantitative enzyme-linked immunosorbent assay and Western blot analysis were employed in this study. In addition, serum FAS levels were significantly higher in breast cancer patients with different clinical stages (Stage II: 0.59+/-0.09 units/l, Stage III: 0.79+/-0.13 units/l, and Stage IV: 1.39+/-0.35 units/l) compared with healthy subjects (0.27+/-0.02 units/l, P<0.05). Taken together, our data suggest that FAS expression may be a useful tumor marker for breast cancer and play a role in assessing cancer virulence.

High anticancer efficacy of L-proline-m-bis (2-chloroethyl) amino-L-phenylalanyl-L-norvaline ethyl ester hydrochloride (MF13) in vivo

The anticancer efficacy of the new anticancer tripeptide, L-proline-m-bis (2-chloroethyl) amino-L-phenylalanyl-L-norvaline ethyl ester hydrochloride (MF13), was investigated in mice. MF13 showed a therapeutic effect in liquid tumors and induced complete remission even in late stage malignancies. MF13 also inhibited human colon cancer growth in nude mice by more than 85% (volume, p<0.001). It acted in a dose-dependent manner and induced a complete regression of tumor in 20% of the mice when the initial dose was high (15 mg/kg, i.p.). Human melanoma exhibited a response to MF13 similar to colon cancer. Activity of MF13 in murine hepatoma in vivo was stronger than its precursor m-sarcolysin (p<0.001). Tumor cells in peritoneal cavities of the MF13 treated (s.c.) mice underwent an irreversible apoptosis. Side effects of MF13 were the transient depression of hemopoiesis and loss of body weight, which vanished within 9-10 days. LD50 of MF13 of a single i.p. injection was 27 mg/kg (94 mg/m2), 11 times higher than the therapeutic dose of a single injection.

Pharmacological inhibition of fatty acid synthase activity produces both cytostatic and cytotoxic effects modulated by p53

Fatty acid synthetic metabolism is abnormally elevated in tumor cells, and pharmacological inhibitors of the anabolic enzyme fatty acid synthase (FAS), including the natural product cerulenin and the novel synthetic compound c75, are selective inhibitors of tumor cell growth. We have recently reported that these two FAS inhibitors both produce rapid, potent inhibition of DNA replication and S-phase progression in human cancer cells, as well as apoptotic death. Here we report an additional characterization of the cellular response to FAS inhibition. RKO colon carcinoma cells were selected for study because they undergo little apoptosis within the first 24 h after FAS inhibition. Instead, RKO cells exhibited a biphasic stress response with a transient accumulation in S and G2 at 4 and 8 h that corresponds to a marked reduction in cyclin A- and B1-associated kinase activities, and then by accumulation of p53 and p21 proteins at 16 and 24 h and growth arrest in G1 and G2. The response of RKO cells to FAS inhibition resembled a genotoxic stress response, but DNA damage did not appear to be an important downstream effect of FAS inhibition, because none was detected using the single cell gel electrophoresis assay (comet assay) to assess DNA damage. p53 function is probably important in protecting RKO cells from FAS inhibition because, similar to many other tumor lines, RKO cells expressing a dominant negative mutant p53 gene underwent extensive apoptosis within 24 h after FAS inhibition. Sensitization of cells to FAS inhibitors by the loss of p53 raises the possibility that these agents may be clinically useful against malignancies carrying p53 mutations. Whereas induction of apoptosis appeared related to accumulation of the substrate, malonyl-CoA, after FAS inhibition, the cytostatic effects were independent of malonyl-CoA accumulation and may have resulted from product depletion.