Twelve oxo-eicosatetraenoic acid induces fetal membrane release after delivery in cows

Fetal fibroblast cell culture from cotyledons of bovine placenta and animal experiments close to term were used to elucidate afterbirth release and factors missing in the signal transduction mechanism for retained fetal membranes (RFM) after delivery. In cell culture the addition of arachidonic acid (Ara) to the medium caused rapid release to free floating cell in the culture dish, accompanied by matrix metalloproteinase (MMP) activation, being consistent with previous in vivo observations, where a relation between MMP and fetal membrane release had been shown. Ara-induced cell floating was not inhibited by the addition of cyclooxygenase (COX) inhibitor, and not induced by the addition of PGF2α or PGE2 to replace Ara, while 12-lipoxygenase (12-LOX) metabolite of Ara, 12-oxo-eicosatetraenoic acid (12-oxoETE), strongly induced cell floating. In the animal experiments, 12-oxoETE injection to delivery-induced cows (n = 6) using prostaglandin (PG) and dexamethazone resulted in rapid release of fetal membranes. In cows with natural calf delivery, a 12-oxoETE peak (11.7-16.8 ng/ml) was observed in maternal blood plasma prior to release of fetal membranes. This investigation thus gives new indications for that the mediator for fetal membrane release is 12-oxoETE and not PG.

Localization of ubiquinone-8 in the Na+-pumping NADH:quinone oxidoreductase from Vibrio cholerae

Na(+) is the second major coupling ion at membranes after protons, and many pathogenic bacteria use the sodium-motive force to their advantage. A prominent example is Vibrio cholerae, which relies on the Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) as the first complex in its respiratory chain. The Na(+)-NQR is a multisubunit, membrane-embedded NADH dehydrogenase that oxidizes NADH and reduces quinone to quinol. Existing models describing redox-driven Na(+) translocation by the Na(+)-NQR are based on the assumption that the pump contains four flavins and one FeS cluster. Here we show that the large, peripheral NqrA subunit of the Na(+)-NQR binds one molecule of ubiquinone-8. Investigations of the dynamic interaction of NqrA with quinones by surface plasmon resonance and saturation transfer difference NMR reveal a high affinity, which is determined by the methoxy groups at the C-2 and C-3 positions of the quinone headgroup. Using photoactivatable quinone derivatives, it is demonstrated that ubiquinone-8 bound to NqrA occupies a functional site. A novel scheme of electron transfer in Na(+)-NQR is proposed that is initiated by NADH oxidation on subunit NqrF and leads to quinol formation on subunit NqrA.

Exploring interactions between the 49 kDa and ND1 subunits in mitochondrial NADH-ubiquinone oxidoreductase (complex I) by photoaffinity labeling

Quinazolines are strong inhibitors of NADH-ubiquinone oxidoreductase (complex I) from bovine heart mitochondria. Using a photoreactive quinazoline, [(125)I]AzQ, and bovine heart submitochondrial particles (SMPs), we demonstrated previously that [(125)I]AzQ binds at the interface of the 49 kDa and ND1 subunits in complex I; it labeled a site in the N-terminal (Asp41-Arg63) region of the 49 kDa subunit, suggesting that this region contacts the ND1 subunit [Murai, M., et al. (2009) Biochemistry 48, 688-698]. The labeled region of ND1 could not be identified because it is highly hydrophobic, and the SMPs did not yield sufficient amounts of labeled protein. Here, we describe how photoaffinity labeling of isolated complex I by [(125)I]AzQ yielded sufficient material for identification of the labeled region of the ND1 subunit. The inhibition of the isolated enzyme by AzQ is comparable to that of SMPs. Our results reveal that the labeled site in ND1 is between Asp199 and Lys262, mostly likely in the third matrix loop that connects the fifth and sixth transmembrane helices. Thus, our results reveal new information about the interface between the hydrophilic and hydrophobic domains of complex I, a region that is thought to be important for ubiquinone reduction and energy transduction.

Reaction mechanism of single subunit NADH-ubiquinone oxidoreductase (Ndi1) from Saccharomyces cerevisiae: evidence for a ternary complex mechanism

The flavoprotein rotenone-insensitive internal NADH-ubiquinone (UQ) oxidoreductase (Ndi1) is a member of the respiratory chain in Saccharomyces cerevisiae. We reported previously that bound UQ in Ndi1 plays a key role in preventing the generation of reactive oxygen species. Here, to elucidate this mechanism, we investigated biochemical properties of Ndi1 and its mutants in which highly conserved amino acid residues (presumably involved in NADH and/or UQ binding sites) were replaced. We found that wild-type Ndi1 formed a stable charge transfer (CT) complex (around 740 nm) with NADH, but not with NADPH, under anaerobic conditions. The intensity of the CT absorption band was significantly increased by the presence of bound UQ or externally added n-decylbenzoquinone. Interestingly, however, when Ndi1 was exposed to air, the CT band transiently reached the same maximum level regardless of the presence of UQ. This suggests that Ndi1 forms a ternary complex with NADH and UQ, but the role of UQ in withdrawing an electron can be substitutable with oxygen. Proteinase K digestion analysis showed that NADH (but not NADPH) binding induces conformational changes in Ndi1. The kinetic study of wild-type and mutant Ndi1 indicated that there is no overlap between NADH and UQ binding sites. Moreover, we found that the bound UQ can reversibly dissociate from Ndi1 and is thus replaceable with other quinones in the membrane. Taken together, unlike other NAD(P)H-UQ oxidoreductases, the Ndi1 reaction proceeds through a ternary complex (not a ping-pong) mechanism. The bound UQ keeps oxygen away from the reduced flavin.

Probing the role of tryptophan-derived secondary metabolism in defense responses against Bipolaris oryzae infection in rice leaves by a suicide substrate of tryptophan decarboxylase

Tryptophan-derived secondary metabolites, including serotonin and its hydroxycinnamic acid amides, markedly accumulate in rice leaves in response to pathogen attack. These compounds have been implicated in the physical defense system against pathogen invasion by being deposited in cell walls. Serotonin is biosynthesized from tryptophan via tryptamine, and tryptophan decarboxylase (TDC) catalyzes the first committed reaction. In this study, (S)-α-(fluoromethyl)tryptophan (S-αFMT) was utilized to investigate the effects of the inhibition of TDC on the defense responses of rice leaves. S-αFMT, enantiospecifically synthesized from L-tryptophan, effectively inhibited TDC activity extracted from rice leaves infected by Bipolaris oryzae. The inhibition rate increased dependently on the incubation time, indicating that S-αFMT served as a suicide substrate. Treatment of rice seedlings with S-αFMT suppressed accumulation of serotonin, tryptamine, and hydroxycinnamic acid amides of serotonin in a dose-dependent manner in B. oryzae-inoculated leaves. The lesions formed on seedlings treated with S-αFMT lacked deposition of brown materials, and those leaves were severely damaged in comparison with leaves without S-αFMT treatment. Administrating tryptamine to S-αFMT-treated leaves restored accumulation of tryptophan-derived secondary metabolites as well as deposition of brown material. In addition, tryptamine administration reduced damage caused by fungal infection. Accordingly, the accumulation of tryptophan-derived secondary metabolites was suggested to be part of the effective defense mechanism of rice.

Regulatory T-cell stability and plasticity in mucosal and systemic immune systems

Regulatory T cells (Treg) express the forkhead box p3 (Foxp3) transcription factor and suppress pathological immune responses against self and foreign antigens, including commensal microorganisms. Foxp3 has been proposed as a master key regulator for Treg, required for their differentiation, maintenance, and suppressive functions. Two types of Treg have been defined. Natural Treg (nTreg) are usually considered to be a separate sublineage arising during thymus differentiation. Induced Treg (iTreg) originate upon T cell receptor (TCR) stimulation in the presence of tumor growth factor beta. Although under homeostatic conditions most Treg in the periphery are nTreg, special immune challenges in the intestine promote more frequently the generation of iTreg. Furthermore, recent observations have challenged the notion that Treg are a stable sublineage, and they suggest that, particularly under lymphopenic and/or inflammatory conditions, Treg may lose Foxp3 and/or acquire diverse effector functions, especially in the intestine, which may contribute to uncontrolled inflammation.

Exploring the binding site of delta(lac)-acetogenin in bovine heart mitochondrial NADH-ubiquinone oxidoreductase

Biochemical characterization of the inhibition mechanism of Deltalac-acetogenins synthesized in our laboratory indicated that they are a new type of inhibitor of bovine heart mitochondrial NADH-ubiquinone oxidoreductase (complex I) [Murai, M., et al. (2006) Biochemistry 45, 9778-9787]. To identify the binding site of Deltalac-acetogenins with a photoaffinity labeling technique, we synthesized a photoreactive Deltalac-acetogenin ([(125)I]diazinylated Deltalac-acetogenin, [(125)I]DAA) which has a small photoreactive diazirine group attached to a pharmacophore, the bis-THF ring moiety. Characterization of the inhibitory effects of DAA on bovine complex I revealed unique features specific to, though not completely the same as those of, the original Deltalac-acetogenin. Using [(125)I]DAA, we carried out photoaffinity labeling with bovine heart submitochondrial particles. Analysis of the photo-cross-linked protein by Western blotting and immunoprecipitation revealed that [(125)I]DAA binds to the membrane subunit ND1 with high specificity. The photo-cross-linking to the ND1 subunit was suppressed by an exogenous short-chain ubiquinone (Q(2)) in a concentration-dependent manner. Careful examination of the fragmentation patterns of the cross-linked ND1 generated by limited proteolysis using lysylendopeptidase, endoprotease Asp-N, or trypsin and their changes in the presence of the original Deltalac-acetogenin strongly suggested that the cross-linked residues are located at two different sites in the third matrix-side loop connecting the fifth and sixth transmembrane helices.

Anti-Mϋllerian hormone and 3D-power Doppler histogram: markers of ovarian function with in vitro fertilization treatment

Purpose

To investigate the ability of three-dimensional (3D) ultrasonography and anti-Mϋllerian hormone (AMH) to predict successful embryo development in patients undergoing in vitro fertilization (IVF) treatment.

Methods

We prospectively studied 28 patients undergoing IVF treatment, using 3D ultrasound Sono automatic volume calculation (AVC) and a 3D-power Doppler volume histogram. Sono AVC was used to automatically measure the number and volume of follicles. The volume histogram was used to measure the vascularization index (VI), flow index, and vascularization flow index in the ovaries. Serum AMH (S-AMH) was determined by enzyme immunoassay (ng/ml).

Results

The number of embryos isolated was 3.3 ± 2.8. The S-AMH of the patients who were under 35 years of age (0.570 ± 0.216 ng/ml) was higher than that in the patients over 40 years of age (0.377 ± 0.071 ng/ml; p = 0.0003). Principal component analyses determined that the quality of the embryo depended on the patients's age, S-AMH, and VI of the ovary. The receiver operating characteristic (ROC) curve showed that the cutoff for the S-AMH was 0.2855 ng/ml, and the optimal age of the patient was 32.5 years, when implanted with an embryo on day 16.

Conclusions

We demonstrated that investigating the relationships between the number of the embryo and ovarian function, using a combination of AMH with a volume histogram, might be useful to predict the response to IVF treatment.

Characterization of the ubiquinone binding site in the alternative NADH-quinone oxidoreductase of Saccharomyces cerevisiae by photoaffinity labeling

The Ndi1 enzyme found in the mitochondrial membrane of Saccharomyces cerevisiae is an NDH-2-type alternative NADH-quinone oxidoreductase. As Ndi1 is expected to be a possible remedy for complex I defects of mammalian mitochondria, a detailed biochemical characterization of the enzyme is needed. To identify the ubiquinone (UQ) binding site in Ndi1, we conducted photoaffinity labeling using a photoreactive biotinylated UQ mimic (compound 2) synthesized following a concept of the least possible modification of the substituents on the quinone ring. Cleavage with CNBr of Ndi1 cross-linked by 2 revealed the UQ ring of 2 to be specifically cross-linked to the Phe281-Met410 region (130 amino acids). Digestion of the CNBr fragment with V8 protease and lysylendopeptidase (Lys-C) gave approximately 8 and approximately 4 kDa peptides, respectively. The approximately 8 kDa V8 digest was identified as the Thr329-Glu399 region (71 amino acids) by an N-terminal sequence analysis. Although the approximately 4 kDa Lys-C digest could not be identified by N-terminal sequence analysis, the band was thought to cover the Gly374-Lys405 region (32 amino acids). Taken together, the binding site of the Q ring of 2 must be located in a common region of the V8 protease, and Lys-C digests Gly374-Glu399 (26 amino acids). Superimposition of the Ndi1 sequence onto a three-dimensional structural model of NDH-2 from Escherichia coli suggested that the C-terminal portion of this region is close to the isoalloxazine ring of FAD.

[Results of neoadjuvant chemotherapy using tri-weekly CDDP/CPT-11 for locally advanced cervical cancer]

OBJECTIVE

We assessed the antitumor response and safety of neoadjuvant chemotherapy (NAC) using cisplatin (CDDP) and irinotecan(CPT-11)given every three weeks for locally advanced cervical cancer with a bulky mass.

SUBJECTS AND METHODS

Nineteen patients with cervical squamous cell cancer in FIGO stage of Ib2 to IIb were enrolled in this study. The FIGO stages were Ib2 in 5 patients, IIa in 2 patients, and IIb in 12 patients. One course of the chemotherapy regimen consisted of intravenous administrations of CDDP at a dose of 70 mg/m 2(day 1)and CPT-11 at 70 mg/m 2 (days 1 and 8) for 21 days, and two courses were administered. This chemotherapy was assessed for antitumor response, adverse events, complete surgical removal rate, progression-free survival time, and overall survival time. RECIST and NCI-CTCAE were used to determine antitumor response and adverse events, respectively.

RESULTS

The results of assessment of the antitumor response showed CR in 3 patients(15. 8%), PR in 14(73. 7%), SD in 1 (5. 3%), and PD in 1(5. 3%). Neutropenia of grade 3 or higher occurred in 13 patients(68. 4%). Anemia occurred in 2 patients(10. 5%), and thrombocytopenia in 1 patient(5. 3%). Nausea and vomiting were observed in 2 patients(10. 5%). All patients underwent a chemotherapy regimen consisting of two courses, and the rate of complete surgical removal was 94. 7%. The median observation period was 27 months; the progression-free survival time was 18 months, and survival time was 27 months.

CONCLUSION

Adverse drug reactions to NAC with the CDDP/CPT-11 combination administered every three weeks were controllable. The antitumor response rate for this chemotherapy was high. These assessment results indicate that NAC with a CDDP/CPT-11 combination was useful for local advanced cervical cancer.

Synthesis and characterization of new piperazine-type inhibitors for mitochondrial NADH-ubiquinone oxidoreductase (complex I)

The mode of action of Deltalac-acetogenins, strong inhibitors of bovine heart mitochondrial complex I, is different from that of traditional inhibitors such as rotenone and piericidin A [Murai, M., et al. (2007) Biochemistry 46 , 6409-6416]. As further exploration of these unique inhibitors might provide new insights into the terminal electron transfer step of complex I, we drastically modified the structure of Deltalac-acetogenins and characterized their inhibitory action. In particular, on the basis of structural similarity between the bis-THF and the piperazine rings, we here synthesized a series of piperazine derivatives. Some of the derivatives exhibited very potent inhibition at nanomolar levels. The hydrophobicity of the side chains and their balance were important structural factors for the inhibition, as is the case for the original Deltalac-acetogenins. However, unlike in the case of the original Deltalac-acetogenins, (i) the presence of two hydroxy groups is not crucial for the activity, (ii) the level of superoxide production induced by the piperazines is relatively high, (iii) the inhibitory potency for the reverse electron transfer is remarkably weaker than that for the forward event, and (iv) the piperazines efficiently suppressed the specific binding of a photoaffinity probe of natural-type acetogenins ([ (125)I]TDA) to the ND1 subunit. We therefore conclude that the action mechanism of the piperazine series differs from that of the original Deltalac-acetogenins. The photoaffinity labeling study using a newly synthesized photoreactive piperazine ([ (125)I]AFP) revealed that this compound binds to the 49 kDa subunit and an unidentified subunit, not ND1, with a frequency of approximately 1:3. A variety of traditional complex I inhibitors as well as Deltalac-acetogenins suppressed the specific binding of [ (125)I]AFP to the subunits. The apparent competitive behavior of inhibitors that seem to bind to different sites may be due to structural changes at the binding site, rather than occupying the same site. The meaning of the occurrence of diverse inhibitors exhibiting different mechanisms of action is discussed in light of the functionality of the membrane arm of complex I.

A pilot study of dental caries status in relation to knowledge, attitudes and practices in oral health in Myanmar

This study was to determine the dental caries prevalence among the Myanmar population, and to investigate the correlations between oral clinical indices and knowledge, attitudes and practices (KAP) on oral health. Subjects were randomly selected from 140,000 people residing in the Kyauktan township in a cross-sectional community-based study. The present analysis was confined to 739 subjects (353 males and 386 females) aged 12, 35-44 and 65-74 years, who were divided into two specified groups based on urban or rural location. KAP on oral health data and social demographic information were collected, while dental caries status was assessed by DMFT. The mean number of decayed teeth (DT) in rural areas was higher than that in urban areas, while the mean number of filled teeth (FT) in rural areas was lower than that in urban areas. Mean knowledge and attitude scores for correct answers were also significantly higher for the urban than the rural subjects. There were statistically significant correlations between the correct/incorrect responses to knowledge and attitude questionnaires on oral health and the mean number of DMFT. KAP pertaining to oral health of Myanmar population, especially those of rural subjects, might not be satisfactory and related to threaten their dental caries status.

Identification of receptors of main sex-pheromone components of three Lepidopteran species

Male moths discriminate conspecific female-emitted sex pheromones. Although the chemical components of sex pheromones have been identified in more than 500 moth species, only three components in Bombyx mori and Heliothis virescens have had their receptors identified. Here we report the identification of receptors for the main sex-pheromone components in three moth species, Plutella xylostella, Mythimna separata and Diaphania indica. We cloned putative sex-pheromone receptor genes PxOR1, MsOR1 and DiOR1 from P. xylostella, M. separata and D. indica, respectively. Each of the three genes was exclusively expressed with an Or83b orthologous gene in male olfactory receptor neurons (ORNs) that are surrounded by supporting cells expressing pheromone-binding-protein (PBP) genes. By two-electrode voltage-clamp recording, we tested the ligand specificity of Xenopus oocytes co-expressing PxOR1, MsOR1 or DiOR1 with an OR83b family protein. Among the seven sex-pheromone components of the three moth species, the oocytes dose-dependently responded only to the main sex-pheromone component of the corresponding moth species. In our study, PBPs were not essential for ligand specificity of the receptors. On the phylogenetic tree of insect olfactory receptors, the six sex-pheromone receptors identified in the present and previous studies are grouped in the same subfamily but have no relation with the taxonomy of moths. It is most likely that sex-pheromone receptors have randomly evolved from ancestral sex-pheromone receptors before the speciation of moths and that their ligand specificity was modified by mutations of local amino acid sequences after speciation.