Mimic of photocycle by a protein folding reaction in photoactive yellow protein

The blue light receptor photoactive yellow protein (PYP) displays rhodopsin-like photochemistry based on the trans to cis photoisomerization of its p-coumaric acid chromophore. Here, we report that protein refolding from the acid-denatured state of PYP mimics the last photocycle transition in PYP. This implies a direct link between transient protein unfolding and photosensory signal transduction. We utilize this link to study general issues in protein folding. Chromophore trans to cis photoisomerization in the acid-denatured state strongly decelerates refolding, and converts the pH dependence of the barrier for refolding from linear to nonlinear. We propose transition state movement to explain this phenomenon. The cis chromophore significantly stabilizes the acid-denatured state, but acidification of PYP results in the accumulation of the acid-denatured state containing a trans chromophore. This provides a clear example of kinetic control in a protein unfolding reaction. These results demonstrate the power of PYP as a light-triggered model system to study protein folding.

Effects of lipids on the interaction of SecA with model membranes

The effects of nonlamellar-prone lipids, diacylglycerol and phosphatidylethanolamine (PE), on the kinetic association of SecA with model membranes were examined by measuring changes in the intrinsic emission fluorescence with a stopped-flow apparatus. Upon interaction with standard liposomes composed of 50 mol% dioleolyphosphatidylcholine (DOPC) and 50 mol% of dioleoylphosphatidylglycerol (DOPG), the intrinsic fluorescence intensity of SecA was decreased after a lapse of time with a rate constant of 0.0049 s(-1). When the DOPC of the standard vesicles was gradually replaced with either dioeloyl PE (DOPE) or Escherichia coli (E. coli) PE, the rate constant increased appreciably as a function of PE concentration, in the order DOPE > E. coli PE. In addition, when the PE of E. coli PE/DOPG (50/50) vesicles was replaced with more than 5 mol% dioleoylglycerol (DOG), the rate constant further increased by 40%. The incorporation of nonlamellar-prone lipids in the vesicles also enhanced the binding of SecA to model membranes in the order DOPE > or = E. coli PE/DOG > E. coli PE > DOPC. These results provide the first kinetic evidence for the importance of nonlamellar-prone phospholipids for the association rate of SecA with membranes.

Prenatal exposure to magnetic field increases dopamine levels in the striatum of offspring

1. The putative effects of prenatal exposure to magnetic field (MF) have recently received much interest. In the present study, mice were exposed to a MF of 50 mT during gestation (0-19 days). 2. After the exposure was terminated, mothers and offspring were returned to normal laboratory conditions. We then determined changes in striatal levels of dopamine (DA) and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the offspring. 3. Our results indicate that prenatal exposure to MF increases levels of DA and DOPAC in the striatum at 4, 8 and 12 weeks postnatally.

Normal brain maturation during childhood: developmental trends characterized with diffusion-tensor MR imaging

PURPOSE

To characterize the maturational changes in water diffusion within central gray matter nuclei and central white matter pathways of the human brain by using diffusion-tensor magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Retrospective analysis of normal MR examination findings in 153 subjects (age range, 1 day to 11 years) referred for clinical neuroimaging was performed. All studies included diffusion tensor-encoded echo-planar MR imaging. Isotropic diffusion coefficient (D) and diffusion anisotropy (A(sigma)) were measured in the corpus callosum, internal capsule, caudate nucleus, lentiform nucleus, and thalamus.

RESULTS

exhibited biexponential decay with age in gray and white matter regions, except for monoexponential decay in the genu of the corpus callosum. There was a steep nonlinear increase of A(sigma) in white matter tracts that paralleled the time course of the decline in D. In basal ganglia, only a small linear increase in A(sigma) was observed in patients. A(sigma) changes in the thalamus were intermediate between basal ganglia and white matter structures.

CONCLUSION

Changes in magnitude and anisotropy of water diffusion follow stereotypical time courses during brain development that can be empirically described with multiexponential regression models, which suggests that quantitative scalar parameters derived from diffusion-tensor MR imaging may provide clinically useful developmental milestones for brain maturity.

Cytoprotective effect of Scutellaria baicalensis in CA1 hippocampal neurons of rats after global cerebral ischemia

Based on the use of Scutellaria baicalensis for the treatment of stroke in traditional Oriental medicine, the current study was carried out to evaluate neuroprotective effects of S. baicalensis after transient global ischemia using rat 4-vessel occlusion model. Methanol extracts from the dried roots of S. baicalensis (0.1-10 mg/kg) administered intra-peritoneally significantly protected CA1 neurons against 10 min transient forebrain ischemia as demonstrated by measuring the density of neuronal cells stained with Cresyl violet. Methanol extract of S. baicalensis inhibited microglial tumor necrosis factor-alpha (TNF-alpha) and nitric oxide production, and protected PC12 cells from hydrogen peroxide-induced toxicity in vitro.

Development of porcine oocytes from preovulatory follicles of different sizes after maturation in media supplemented with follicular fluids

The development of porcine oocytes from large (3.1-8.0 mm in diameter) or small (<3.1 mm) follicles was examined after maturation culture in medium containing porcine follicular fluid (pFF). Large follicles yielded larger (256 microm v. 221 microm; P<0.05) cumulus-oocyte complexes and more (22 v. 14%) morphologically normal oocytes than small follicles (Experiment 1). In Experiments 2-4, maturation media supplemented with mixed pFF (10%) from small and large follicles was used. More oocytes from large follicles matured (58% v. 91%), formed pronuclei (81% v. 90%) and developed to the blastocyst stage (2% v. 10%) than oocytes from small follicles. In Experiments 5-7, the effects of pFF collected from either small or large follicles on oocyte development were examined. Regardless of the source of oocytes, large-follicle-derived pFF more significantly enhanced preimplantation development than did small-follicle-derived pFF. The highest rate of blastocyst formation (16%) was found when oocytes from large follicles were cultured in maturation medium containing large-follicle-derived pFF. These results suggest that oocytes from large follicles have greater developmental potential than oocytes from small follicles, and that the origin of pFF, which is added to the maturation media, might be an important factor for improving in vitro development of porcine oocytes.

The influences of extremely low frequency magnetic fields on clonidine-induced sleep in 2-day-old chicks

1. It has been shown that magnetic fields (MFs) affect a variety of biological effects in animal brains. There have been few experiments on the effects of MFs on sleep. Therefore, we investigated whether extremely low frequency (ELF) MFs affect the sleep induced by clonidine, a central alpha(2)-adrenoceptor agonist. Clonidine produced dose-related increase of the sleeping time and dose-related decrease of the onset time in 2-day-old chicks. 2. Exposure of chicks to MFs (5, 10, 20 G; for 3, 6, 9, 12 h) significantly increased the clonidine-induced sleep time as a direct function of intensity and duration of MF application. Clonidine reduced noradrenaline or tyrosine in the brain, an effect which was not further changed in animals exposed to MF. 3. To determine whether the gamma amino butyric acid A (GABA(A))/benzodiazepine (BZD) receptor system is involved in the decrease in clonidine-induced sleep caused by activation of central alpha(2)-adrenergic systems, we examined exposure of chicks to the effects of the BZD receptor antagonist flumazenil (0.5 mg kg(-1), i.p.) and GABA(A) antagonist bicuculline (0.1 mg kg-1, i.p.) on clonidine-induced sleep. Bicuculline and flumazenil inhibited the increase of clonidine-induced sleep time by MFs. Clonidine or MFs did not change GABA levels in the brain. 4. These results suggest that MFs can increase clonidine-induced sleep via a change of GABA(A) and BZD receptor system irrespective of the concentration of GABA or noradrenaline in the brain of 2-day-old chicks.

Effect of IP3 and ryanodine treatments on the development of bovine parthenogenetic and reconstructed embryos

For parthenogenetic activation as a model system of nuclear transfer, microinjection and electroporation as activation treatments in bovine metaphase II oocytes were administered to each of three groups as follows: control group (treatments with Ca2+, Mg2+ -free PBS+100 micro M EGTA), IP3 group (control+25 micro M IP3) and IP3+ ryanodine group (control+25 micro M IP3+10 mM ryanodine). In experiments using microinjection, no significant differences were observed between any of the developmental stages of the electroporation experiment. For electroporation, cleavage rates were significantly higher in the IP3+ryanodine group than in the IP3 or control group (85.6% vs 73.7% or 67.6%, respectively). In the subsequent stages of embryonic development, such as morula and blastocyst formation, the IP3 and ryanodine group exhibited significantly higher rates of morula fomation than the IP3 or control groups (40.6% vs 24.2% or 16.7%, respectively). Similarly, the rate of blastocyst formation in the IP3+ryanodine group was significantly higher than the control group (16.3% vs 6.9%) but did not differ significantly from the IP3 group (16.3% vs 9.5%). In nuclear transfer, activation was performed at 30 hpm by microinjection and elecroporation with 25 micro M IP3+ 10 mM ryanodine followed by 6-DMAP treatment. No significant differences were observed at any stage of embryonic development and none of the embryos activated by electroporation reached either the morula or blastocyst stage. However, 3.8% and 1.9% of embryos activated by microinjection sucessfully developed to the morula and blastocyst stages, respectively. In conclusion, activation treatments using IP3 and ryanodine are able to support the development of bovine parthenogenetic and reconstructed embryos.

Folding and signaling share the same pathway in a photoreceptor

The photoreceptor photoactive yellow protein (PYP) was used as a model system to study receptor activation and protein folding. Refolding was studied by stopped-flow absorbance spectroscopy for PYP with either a trans or a cis chromophore. Chromophore trans to cis isomerization, the mechanism of light detection by PYP, greatly affects the protein folding process. When the cis chromophore is present, refolding from the unfolded state proceeds through the putative signaling state of PYP as an on-pathway intermediate. In addition, moderate denaturant concentrations result in the specific unfolding of the signaling state of PYP. Thus, the signaling state is common to the pathways of folding and signaling. This result provides an avenue for the study of protein folding. We demonstrate how this approach can be used to establish whether a folding intermediate is on-pathway or off-pathway. The results also reveal transient partial unfolding as a molecular mechanism for signaling.

Reorganization of nuclear factors during myeloid differentiation

Differentiation in several stem cell systems is associated with major morphological changes in global nuclear shape. We studied the fate of inner-nuclear structures, splicing factor-rich foci and Cajal (coiled) bodies in differentiating hemopoietic, testis and skin tissues. Using antibodies to the splicing factors PSF, U2AF(65) and snRNPs we find that these proteins localize in foci throughout the nuclei of immature bone marrow cells. Yet, when granulocytic cells differentiate and their nuclei condense and become segmented, the staining localizes in a unique compact and thread-like structure. The splicing factor-rich foci concentrate in the interior of these nuclei while the nuclear periphery and areas of highly compact chromatin remain devoid of these molecules. Differentiated myeloid cells do not stain for p80 coilin, the marker for Cajal bodies. Immature myeloid cells contain Cajal bodies although these usually do not coloclaize with PSF-rich foci. Following complete inhibition of transcription in myeloid cells, the threaded PSF pattern becomes localized in several foci in the different lobes of mature granulocytes while in human HL-60 immature myeloid leukemia cells PSF is found in the perinucleolar compartment. Studies of other differentiating stem cell systems show that PSF staining disappears completely in differentiated, transcriptionally inactive sperm cells, is scarce as cells migrate from the inner skin layers outward and is lost as cells of the hair follicle mature. We conclude that the formation and distribution of splicing factor-rich foci in the nucleus during differentiation of various cell lineages is dependent on the levels of chromatin condensation and the differentiation status of the cell.

Skin microvascular vasodilatory capacity in offspring of two parents with Type 2 diabetes

AIMS

Microvascular dysfunction occurs in Type 2 diabetes and in subjects with fasting hyperglycaemia. It is unclear whether this dysfunction relates to dysglycaemia. This study investigated in normogylcaemic individuals whether a genetic predisposition to diabetes, or indices of insulin resistance including endothelial markers, were associated with impaired microvascular function.

METHODS

Maximum microvascular hyperaemia to local heating of the skin was measured using laser Doppler flowmetry in 21 normoglycaemic subjects with no family history of diabetes (Group 1) and 21 normoglycaemic age, sex and body mass index-matched offspring of two parents with Type 2 diabetes (Group 2).

RESULTS

Although Group 2 had normal fasting plasma glucose and glucose tolerance tests, the 120-min glucose values were significantly higher at 6.4 (5.3-6.6) mmol/l (median (25th - 75th centile)) than the control group at 4.9 (4.6-5.9) mmol/l (P = 0.005) and the insulinogenic index was lower at 97.1 (60.9-130.8) vs. 124.0 (97.2-177.7) (P = 0.027). Skin maximum microvascular hyperaemia (Group 1: 1.56 (1.39-1.80) vs. Group 2: 1.53 (1.30-1.98) V, P = 0.99) and minimum microvascular resistance which normalizes the hyperaemia data for blood pressure (Group 1: 52.0 (43.2-67.4) vs. Group 2: 56.0 (43.7-69.6) mmHg/V, P = 0.70) did not differ in the two groups. Significant positive associations occurred between minimum microvascular resistance and indices of the insulin resistance syndrome; plasminogen activator inhibitor type 1 (R(s) = 0.46, P = 0.003), t-PA (R(s) = 0.36, P = 0.03), total cholesterol (R(s) = 0.35, P = 0.02), and triglyceride concentration (R(s) = 0.35, P = 0.02), and an inverse association with insulin sensitivity (R(s) = -0.33, P = 0.03).

CONCLUSIONS

In normoglycaemic adults cutaneous microvascular vasodilatory capacity is associated with features of insulin resistance syndrome, particularly with plasminogen activator inhibitor type 1. A strong family history of Type 2 diabetes alone does not result in impairment in the maximum hyperaemic response. Diabet. Med. 18, 541-545 (2001)

PAS domain receptor photoactive yellow protein is converted to a molten globule state upon activation

Biological signaling generally involves the activation of a receptor protein by an external stimulus followed by protein-protein interactions between the activated receptor and its downstream signal transducer. The current paradigm for the relay of signals along a signal transduction chain is that it occurs by highly specific interactions between fully folded proteins. However, recent results indicate that many regulatory proteins are intrinsically unstructured, providing a serious challenge to this paradigm and to the nature of structure-function relationships in signaling. Here we study the structural changes that occur upon activation of the blue light receptor photoactive yellow protein (PYP). Activation greatly reduces the tertiary structure of PYP but leaves the level secondary structure largely unperturbed. In addition, activated PYP exposes previously buried hydrophobic patches and allows significant solvent penetration into the core of the protein. These traits are the distinguishing hallmarks of molten globule states, which have been intensively studied for their role in protein folding. Our results show that receptor activation by light converts PYP to a molten globule and indicate stimulus-induced unfolding to a partially unstructured molten globule as a novel theme in signaling.

Births of freemartins derived from embryos reconstructed with ear fibroblasts

Although the combination of artificial insemination (AI) and embryo transfer (ET) is effective for preventing large offspring syndrome in clone cattle production, it may cause freemartinism. In this study, 51 reconstructed embryos were transferred to artificially inseminated recipients. Of those 9 twin pregnancies, three delivered male and female offsprings. The females had tufts of long coarse hair and short blind pouch at the vaginal end. At necropsy, hypoplastic testicles and epididymis, which connected to the uterus through the spermatic cord, were found and seminal vesicles were also noted. All females had mixed sex chromosome configuration (60, XX and 60, XY). These results suggest that the combined ET program can cause freemartinism, which reduces the efficiency of clone cattle production.

A qualitative assessment of children's farm safety day camp programs

In order to increase farm safety awareness and teach children good safety habits, farm safety day camp programs have been initiated in many communities. For the most part, the effectiveness of the programs is unknown because few evaluations have been performed. The purpose of this project was to qualitatively assess the overall strengths and weaknesses of farm safety day camp programs and to generate recommendations for future programs. Interviews, a literature search, and observations were used to identify strengths and weaknesses of the farm safety day camp programs. Major strengths of the programs are that: 1) positive attention is given to agriculture and agricultural safety; 2) programs are hands-on, interactive, and fun; 3) children gain knowledge about farm safety; 4) programs bring a community together to work toward a common goal; and 5) children talk to parents about safety. Key weaknesses of farm safety day camp programs are that: 1) there is a lack of parental involvement in many of the programs; 2) it is hard to change patterns of behavior in one day; 3) programs are expensive and time consuming; 4) curricula may include content that is inaccurate or inappropriate for the age of participants; and 5) evaluation is difficult. When done well, farm safety day camp programs can teach children about safety and influence safety practices affecting children on the farm. Recommendations for future farm safety day camp programs are: 1) ensure that child-development principles are applied to all aspects of program activities and curricula; 2) provide session leaders with accurate and relevant content; 3) increase parental involvement; and 4) address safety issues throughout the year.

Cloning and characterization of a hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase induced in response to UV-C and wounding from Capsicum annuum

Hydroxycinnamoyl-CoA : tyramine N-(hydroxycinnamoyl) transferase (THT) is a pivotal enzyme in the synthesis of N-(hydroxycinnamoyl)-amines, which are associated with cell wall fortification in plants. The cDNA encoding THT was cloned from the leaves of UV-C treated Capsicum annuum (hot pepper) using a differential screening strategy. The predicted protein encoded by the THT cDNA is 250 amino acids in length and has a relative molecular mass of 28,221. The protein sequence derived from the cDNA shares 76% and 67% identity with the potato and tobacco THT protein sequences, respectively. The recombinant pepper THT enzyme was purified using a bacterial overexpression system. The purified enzyme has a broad substrate specificity including acyl donors such as cinnamoyl-, sinapoyl-, feruloyl-, caffeoyl-, and 4-coumaroyl-CoA and acceptors such as tyramine and octopamine. In UV-C treated plants, the THT mRNA was strongly induced in leaves, and the elevated level of expression was stable for up to 36 h. THT mRNA also increased in leaves that were detached from the plant but not treated with UV-C. THT expression was measured in different plant tissues, and was constitutive at a similar level in leaf, root, stem, flower and fruit. Induction of THT mRNA was correlated with an increase in THT protein.

Design of a wavelet interpolation filter for enhancement of the ST-segment

A wavelet interpolation filter (WIF) is designed for the removal of motion artifacts in the ST-segment of stress ECGs. The WIF consists of two parts. One part is a wavelet transform that decomposes the stress ECG signal into several frequency bands using a Haar wavelet. The other part is an interpolation method, such as the spline technique, that is used to enhance the reconstruction performance of the signal decomposed by the wavelet transform. To evaluate the performance of the WIF, three indices are used: signal-to-noise ratio (SNR), reconstruction square error (RSE) and standard deviation (SD). The MIT/BIH arrhythmia database, the European ST-T database and the triangular wave are used for evaluation. A noisy ECG signal, corrupted by motion artifacts, is simulated by the addition of two types of random noise to the original ECG signal. For comparison, three indices for the other methods are also computed: mean, median and hard thresholding. The performance of the WIF shows that RSE, SNR and SD are 392.7, 18.3dB and 2.6, respectively, in the case of a noisy signal with an SNR of 7.1 dB. This result is much better than those for the other methods.

A separate procedure of fusion and activation in an ear fibroblast nuclear transfer program improves preimplantation development of bovine reconstituted oocytes

This study was conducted to examine whether preimplantation development of bovine ("HanWoo," Bos Taurus corcanae) oocytes reconstituted with ear fibroblasts could be improved by a modified procedure of fusion and activation. In Experiment 1, enucleated oocytes were reconstituted with ear fibroblast by a combined procedure of electric fusion and activation at either 24 or 28 hours after IVM. The 28 hours reconstitution yielded more blastocysts (4% vs. 21%, P = 0.0025) and higher ratio of blastocysts per 2-cell embryos (0.05 vs. 0.25, P = 0.003) than the 24 hours. In Experiment 2, enucleated oocytes were reconstituted by one of the three fusion and activation protocols; 1) a combined procedure of electric fusion and activation at 28 hours after IVM, 2) a combined procedure of electric fusion and chemical activation at 28 hours, and 3) a separate procedure of electric fusion at 24 hours and chemical activation at 28 hours. When compared two combined procedures, chemical activation with 5 microM ionomycin for 4 minutes did not promote embryo development and significantly reduced the fusion rate (42% vs. 53%, P = 0.0395). However, significant (P < 0.0113) increases in the development to 2-cell (90% vs. 70 to 74%) and blastocyst (47% vs. 7 to 13%) stages and in the ratio of blastocysts per 2-cell embryos (0.52 vs. 0.11 to 0.18) were obtained by a separate procedure of electric fusion and chemical activation than by the combined procedures. This separate protocol did not reduce the fusion rate compared with the combined procedures (58%). In conclusion, improved development of oocytes reconstituted with ear fibroblasts was achieved by undergoing a separate procedure of electric fusion and chemical activation 4 hours apart.

High-resolution blood oxygen-level dependent MR venography (HRBV): a new technique

Our purpose of this study was to demonstrate the clinical potential and spatial resolution of a new MRI technique: high-resolution blood oxygen-level dependent venography (HRBV), in well-known intracranial vascular lesions, such as cavernous and venous angiomas, and venous sinus thrombosis. HRBV provides unique high-resolution information on veins without administration of contrast medium. The data are independent of conventional findings on MRI and potentially useful in characterising and demonstrating the architecture of vascular lesions of the brain.

Immunohistochemical detection of Prion protein (PrP-Sc) and epidemiological study of BSE in Korea

Though the aetiology of transmissible spongiform encephalopathies (TSEs) remains uncertain, proteinase resistant prion protein (PrP-Sc), a converted form of the normal cellular prion protein (PrP-C), accumulates in the lysosome of cells of the nervous systems of animals with TSEs. In this study, clinical and epidemiological examinations of bovine spongiform encephalopathy (BSE) were conducted in Korea. During the investigated period, none of the cattle exhibited typical clinical signs of BSE, such as behavioral disturbances, high sensitivity, and abnormal locomotion. Immunohistochemical analysis and western immunoblotting were established to detect PrP-Sc in the brain tissue using monoclonal antibody (MAb) F89/160.1.5, produced by immunizing mice with a synthetic peptide which corresponds to bovine PrP residues 146-159, NH2-SRPLIHFGSDYEDRC-COOH. Although some BSE-like spongiform changes were observed in bovine brains randomly collected from Korean slaughterhouses from 1996 to 1999, no PrP-Sc was detected in those brains with the established immunohistochemistry and western immunoblotting assay. Also, no positive reaction was observed in bovine brains infected with rabies. These immunohistochemical and western immunoblotting methods using MAbs, specifically reactive with conserved epitopes on ruminant PrP, can be used for postmortem diagnosis of BSE. Further, the method can be applied to antemortem and the preclinical diagnosis of ovine scrapie by detecting PrP-Sc in lymphoid tissues, such as the tonsils, third eyelid or peripheral lymph nodes.

Evaluation of a reduced MR imaging sequencing protocol in adult patients with stroke

PURPOSE

To compare a reduced (three-sequence) magnetic resonance (MR) imaging protocol with a full (eight- to 10-sequence) MR imaging protocol in adults suspected of having stroke.

MATERIALS AND METHODS

Six neuroradiologists interpreted a consecutive sample of 265 MR images in patients suspected of having stroke. Each read reduced-protocol images in a discrete series of 40 patients (one read images in only 15) and corresponding full-protocol images 1 month later (reduced/full protocol). Five of the readers each read images in 10 additional cases, five each as full/full and reduced/reduced protocol controls. kappa values between full and reduced protocols, reader assessment of protocol adequacy, confidence level, and need for additional sequences or examinations were evaluated.

RESULTS

In the reduced/full protocol, the kappa value for detecting ischemia was 0.797; and that for detecting any clinically important abnormality, 0.635. Statistically similar kappa values were found with the full/full control design (kappa = 0.802 and 0.715, respectively). The full protocol was judged more adequate than the reduced protocol (2.0 of 5.0 points vs 1.6, P <.001) and generated greater diagnostic confidence (8.6 of 10.0 points vs 8.9, P =.01), less need for additional sequences (2.7 of 6.0 points vs 1.5, P <.001), and more requests for additional examinations (28.4% vs 36.3%).

CONCLUSION

Disagreement between interpretations of reduced- and full-protocol images might be attributable to baseline-level intraobserver inconsistency, as demonstrated in control designs. A greater number of sequences did not lead to greater consistency.

fbpABC gene cluster in Neisseria meningitidis is transcribed as an operon

The neisserial fbpABC locus has been proposed to constitute a single transcriptional unit. To confirm this operonic arrangement, transcription assays using reverse transcriptase PCR amplification were conducted with Neisseria meningitidis. The presence of fbpAB and fbpBC transcripts obtained by priming cDNA synthesis with an fbpC-sequence-specific oligonucleotide indicates that fbpABC is organized as a single expression unit. The ratio of fbpA to fbpABC mRNA was approximately between 10- to 20-fold, as determined by real-time quantitative PCR.

Enantiomeric purity test of bevantolol by reversed-phase high performance liquid chromatography after derivatization with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate

A reversed-phase high-performance liquid chromatographic method was developed to determine the optical purity of bevantolol enantiomers. (S)-(-)-Menthyl chloroformate((-)-MCF), (S)-(-)-alpha-methylbenzyl isocyanate((-)-MBIC) and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate(GITC), which can react with the secondary amine group of bevantolol were investigated as chiral derivatization reagents. Among them indirect chiral HPLC method using GITC gave the best result. The derivatization proceeded quantitatively within 20 min at room temperature. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 20min using ODS column. Different ratios of (S)-(-)-bevantolol and (R)-(+)-bevantolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with GITC, on a ODS column. No racemization was found during the experiment. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequete linearity over the required range.

Embryotropic role of hemoglobin and ethylenediaminetetraacetic acid in preimplantation development of ICR mouse 1-cell embryos

OBJECTIVE

To evaluate embryotropic action of hemoglobin (Hb) and ethylenediaminetetraacetic acid (EDTA) on preimplantation embryo development.

DESIGN

In vitro model study using mouse embryos.

SETTING

University affiliated hospital, Pochon CHA University.

ANIMALS

Four-week-old block strain ICR mice naturally mated after superovulation.

INTERVENTION(S)

One-cell embryos were cultured in serum-free, modified preimplantation-1 medium, to which 1 microg/ml Hb and/or 0.1 mM EDTA were added.

MAIN OUTCOME MEASURE(S)

Preimplantation development and blastomere number.

RESULT(S)

More (P<.05) 1-cell embryos developed to the 4-cell (52% vs. 67%-84%), 8-cell (48% vs. 65%-81%), and blastocyst (40% vs. 61%-79%) stages after the addition of hemoglobin (Hb) and/or EDTA than after no addition. Highest proportion of embryos developed to each stage after the combined addition of Hb+EDTA. EDTA specifically stimulated the development before the 8-cell stage, which was as similar as Hb+EDTA. On the contrary, higher ratio of morula to blastocyst transformation was obtained after the addition of Hb or Hb+EDTA than after no addition (0.76 vs. 0.96-0.98). Significant increases in the cell number of blastocysts (46.5-47.2 vs. 53.2 cells), inner cell mass (ICM) cells (16.7-17.5 vs. 21 cells), and the ratio of ICM cells to trophoblasts (0.3-0.37 to 0.39) were found after the combined addition of Hb+EDTA, compared with no addition or with the addition of EDTA or Hb alone.

CONCLUSIONS

Hb and EDTA have stage-specific effects on supporting preimplantation embryo development; Hb promotes both the development before the 8-cell stage and the morula to blastocyst transformation, whereas EDTA mainly promotes the development to the 8-cell stage. The combined exposure of embryos to Hb and EDTA improves not only preimplantation development but also the growth and quality of blastocysts.