Relationship between the acid-inhibitory effects of two proton pump inhibitors and CYP2C19 genotype in Japanese subjects: a randomized two-way crossover study.

This two-way crossover study investigated possible differences between the proton pump inhibitors, omeprazole and rabeprazole, in their effect on gastric acid secretion in Japanese subjects with differing cytochrome P450, family 2, subfamily C, polypeptide 19 (CYP2C19) genotypes. A total of 23 Helicobacter pylori-negative healthy volunteers received omeprazole 20 mg/day and rabeprazole 10 mg/day. Each drug treatment was given for a continuous 7-day period allocated in random order, with an interval of at least 1 week between drug treatment periods to allow for wash-out. Intragastric pH was measured on days 1 and 7. Overall median intragastric pH levels at 7 and 8 h after the first administration were significantly higher with omeprazole. There was no significant difference in intragastric pH in homozygous extensive metabolizers, whereas intragastric pH was significantly higher with omeprazole in combined data from heterozygous extensive metabolizers and poor metabolizers at 6, 7 and 8 h after the first drug administration. There were no significant differences in intragastric pH between omeprazole and rabeprazole irrespective of genotype on day 7 of administration. In conclusion, on day 1 the time to onset of the antisecretory action of 20 mg/day omeprazole was more rapid than that of 10 mg/day rabeprazole in Japanese individuals who have a higher incidence of the CYP2C19 poor metabolizer genotype, however by day 7 no difference in antisecretory effect was found, regardless of genotype.

The clock gene cryptochrome of Bactrocera cucurbitae (Diptera: Tephritidae) in strains with different mating times.

Differences in mating time between populations can give rise to premating reproductive isolation. Tephritid fruit flies exhibit large variation in mating time among intra- or inter-specific populations. We previously cloned the clock gene period from two strains of melon fly, Bactrocera cucurbitae; in one the individuals mate early during the day, whereas in the other the individuals mate later. These strains were originally established by divergent artificial selection for developmental time, 'short' and 'long', with early and late mating times, respectively. The deduced amino acid sequences of PERIOD proteins for these two strains were reported to be identical. Here we cloned another clock gene cryptochrome (cry) from the two strains, and found two stable amino acid substitutions in the strains. In addition, the allele frequency at the two polymorphic sites of cry gene correlated with the circadian locomotor period (tau) across strains, whereas the expression pattern of cry mRNA in the heads of flies taken from the short strain significantly differed from that from the long strain. These findings suggest that variation in the cry gene is related to differences in the circadian behaviour in the two strains, thus implying that the cry gene may have an important role in reproductive isolation.

Smelling, tasting, learning: Drosophila as a study case.

Understanding brain function is to account for how the sensory system is integrated with the organism's needs to organize behaviour. We review what is known about these processes with regard to chemosensation and chemosensory learning in Drosophila. We stress that taste and olfaction are organized rather differently. Given that, e.g., sugars are nutrients and should be eaten (irrespective of the kind of sugar) and that toxic substances should be avoided (regardless of the kind of death they eventually cause), tastants are classified into relatively few behavioural matters of concern. In contrast, what needs to be done in response to odours is less evolutionarily determined. Thus, discrimination ability is warranted between different kinds of olfactory input, as any difference between odours may potentially be or become important. Therefore, the olfactory system has a higher dimensionality than gustation, and allows for more sensory-motor flexibility to attach acquired behavioural 'meaning' to odours. We argue that, by and large, larval and adult Drosophila are similar in these kinds of architecture, and that additionally there are a number of similarities to vertebrates, in particular regarding the cellular architecture of the olfactory pathway, the functional slant of the taste and smell systems towards classification versus discrimination, respectively, and the higher plasticity of the olfactory sensory-motor system. From our point of view, the greatest gap in understanding smell and taste systems to date is not on the sensory side, where indeed impressive advances have been achieved; also, a satisfying account of associative odour-taste memory trace formation seems within reach. Rather, we lack an understanding as to how sensory and motor formats of processing are centrally integrated, and how adaptive motor patterns actually are selected. Such an understanding, we believe, will allow the analysis to be extended to the motivating factors of behaviour, eventually leading to a comprehensive account of those systems which make Drosophila do what Drosophila's got to do.

Inverse silica opal photonic crystals for optical sensing applications.

This work reports fabrication of inverse silica opal photonic crystal structures from direct polystyrene micro sphere opals using low-temperature sol-gel infiltration of silica, and examines performance of these photonic crystals as environmental refractive index sensors. Sensitivity of the spectral position and optical attenuation of photonic stop gaps is found to allow detection of the index changes by the amount of ~10(-3). The high value of sensitivity, which is comparable with those of other optical sensing techniques, along with simplicity of the optical detection setup required for sensing, and the low-temperature, energy-efficient fabrication process make inverse silica opals attractive systems for optical sensing applications.

Molecular neurophysiology of taste in Drosophila.

The recent identification of candidate receptor genes for sweet, umami and bitter taste in mammals has opened a door to elucidate the molecular and neuronal mechanisms of taste. Drosophila provides a suitable system to study the molecular, physiological and behavioral aspects of taste, as sophisticated molecular genetic techniques can be applied. A gene family for putative gustatory receptors has been found in the Drosophila genome. We discuss here current knowledge of the gustatory physiology of Drosophila. Taste cells in insects are primary sensory neurons whereupon each receptor neuron responds to either sugar, salt or water. We found that particular tarsal gustatory sensilla respond to bitter compounds. Electrophysiological studies indicate that gustatory sensilla on the labellum and tarsi are heterogeneous in terms of their taste sensitivity. Determination of the molecular bases for this heterogeneity could lead to an understanding of how the sensory information is processed in the brain and how this in turn is linked to behavior.

Effects of prenatal rubratoxin-B exposure on behaviors of mouse offspring.

The effects of prenatal rubratoxin-B (RB) exposure on 8 behavioral parameters in JCL:ICR mice were assessed. Pregnant mice were injected intraperitoneally with 0.1 or 0.2 mg/kg/day of RB dissolved in propylene glycol water solution on days 7-9 (Group A) or 10-12 (Group B) of gestation. Controls received the vehicle similarly on days 7-12 of gestation. Before weaning, the offspring of both sexes were examined to test their the surface righting reflex (5 days of age), cliff avoidance response (6 days), negative geotaxis response (7 days), and swimming development (8, 10, and 12 days). After weaning, male animals were examined using the rotarod test (6 weeks of age), the open-field test (7 weeks), the shuttle-box-avoidance-learning test (9 weeks), and the water E-maze test (10 weeks). The preweanling offspring in the 0.2 mg/kg-B group showed significantly lower success rates and longer response times than controls in the cliff-avoidance response. In swimming development, the offspring in the 0.2 mg/kg B group had significantly lower scores than controls for swimming angle at 10 and 12 days of age. The avoidance learning of the mice in all RB-exposed A and B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to RB produced a delay of early response development and impaired learning ability in the offspring of mice exposed to RB during middle pregnancy.

Properties and human origin of two angiotensin-I-converting enzyme inhibitory peptides isolated from a tryptic hydrolysate of human serum albumin.

Two angiotensin-I-converting enzyme (ACE) inhibitory peptides were isolated from a tryptic hydrolysate of human serum albumin (HSA). The peptides were identified by sequencing and other analyses as Ala-Trp and the nonapeptide Ala-Phe-Lys-Ala-Trp-Ala-Val-Ala-Arg (human albutensin A), corresponding to f(213-214) and f(210--218) of HSA, respectively. Synthetic versions of both peptides had previously been shown to have ACE inhibitory activity. The present results are the first to show that these peptides have a potential natural origin in humans. Additional studies were done to define the inhibitory properties of these peptides, as they had not been previously reported. The dipeptide and nonapeptide showed dose-dependent inhibition of ACE, with IC50 values of 12 and 1.7 micromol/l, respectively. Lineweaver-Burk plots suggested that Ala-Trp is a competitive inhibitor, and that human albutensin A is a noncompetitive inhibitor.

Molecular cloning and characterization of a putative cyclic nucleotide-gated channel from Drosophila melanogaster.

We have cloned a cDNA encoding a putative cyclic nucleotide-gated (CNG) channel from Drosophila melanogaster. The N-terminal half of the predicted protein, designated as CNGL, shows a high degree of sequence similarity with the known CNG channel proteins. CNGL has a long hydrophilic C-terminal stretch that is absent in other CNG channels. Northern blot analysis revealed that the messenger RNA (mRNA) corresponding to the size of the cloned cDNA is expressed in Drosophila heads. Immunolocalization studies showed that CNGL is expressed in the brain, including the medulla, lobulla and lobulla plate, the antennal lobe glomeruli, and mushroom bodies. These results suggest a possible role of the putative CNGL channel in the processing of visual and olfactory information in the nervous system of Drosophila.

Molecular identification of a taste receptor gene for trehalose in Drosophila.

The molecular nature of sweet taste receptors has not been fully explored. Employing a differential screening strategy, we identified a taste receptor gene, Tre1, that controls the taste sensitivity to trehalose in Drosophila melanogaster. The Tre1 gene encodes a novel protein with similarity to G protein-coupled seven-transmembrane receptors. Disruption of the Tre1 gene lowered the taste sensitivity to trehalose, whereas sensitivities to other sugars were unaltered. Overexpression of the Tre1 gene restored the taste sensitivity to trehalose in the Tre1 deletion mutant. The Tre1 gene is expressed in taste sensory cells. These results provide direct evidence that Tre1 encodes a putative taste receptor for trehalose in Drosophila.

Effects of prenatal aflatoxin B1 exposure on behaviors of rat offspring.

The effects of prenatal aflatoxin B1 (AFB) exposure on eight behavioral parameters in Jcl:Wistar rat offspring were assessed. Pregnant rats were injected subcutaneously with 0.3 mg/kg/day of AFB dissolved in dimethylsulfoxide on days 11-14 (Group A) or 15-18 (Group B) of gestation. Controls received the vehicle similarly on days 11-18 of gestation. Before weaning, the offspring were examined using the cliff avoidance response (5 days of age), the negative geotaxis reflex (7 days), and swimming development (6, 8, and 10 days). After weaning, animals were examined using the rotarod test (5 weeks of age), the open field test (6 weeks), a conditioned avoidance learning test (14 weeks), an underwater T-maze test (15 weeks), and a reproduction test (16 weeks). The preweaning offspring in the AFB-A group showed significantly lower success rates than controls in cliff avoidance responses. In swimming development, the offspring in the AFB-A group had significantly lower scores than controls for swimming direction. In the rotarod test, the AFB-A group remained on the rod for a significantly shorter time than the controls at 15 rpm on both the first and second trial days. The avoidance performance of the rats in AFB-A and AFB -B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to AFB produced a delay of early response development, impaired locomotor coordination, and impaired learning ability in the offspring of rats exposed to AFB during middle pregnancy, and the early gestational exposure appears to produce more effects than latter exposure.

Isolation of acein-2, a novel angiotensin-I-converting enzyme inhibitory peptide derived from a tryptic hydrolysate of human plasma.

We previously described a novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated Acein-1, that was isolated from a tryptic hydrolysate of human plasma. We now report a second such inhibitory peptide, Acein-2 obtained from the same hydrolysate. The peptide was purified by gel filtration and cation exchange chromatography followed by reversed-phase gradient and isocratic high performance liquid chromatography. Acein-2 was found to be a tripeptide, Leu-Ile-Tyr, which is thought to correspond to f(518-520) of human alpha2-macroglobulin. The synthetic tripeptide showed a potent dose-dependent inhibition of ACE, with an IC(50) value of 0.82 micromol/l. Lineweaver-Burk plots suggested that Acein-2 as well as the previously described Acein-1 are non-competitive inhibitors.

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm.

BACKGROUND: Light is the major environmental signal for the entrainment of circadian rhythms. In Drosophila melanogaster, the period(per) and timeless (tim) genes are required for circadian behavioural rhythms and their expression levels undergo circadian fluctuations. Light signals can entrain these rhythms by shifting their phases. However, little is known about the molecular mechanism for the perception and transduction of the light signal. The members of the photolyase/cryptochrome family contain flavin adenine dinucleotide (FAD) as chromophore and are involved in two diverse functions, DNA repair and photoreception of environmental light signals. RESULTS: We report the cloning of a new member of this family, dcry, from Drosophila. Northern blot analysis shows that this gene is expressed in various tissues. The dcry mRNA is expressed in a circadian manner in adult heads, while such rhythmic fluctuation is abolished in the clock-defective per0 and tim0 mutants. The circadian expression is dampened down in constant darkness. The over-expression of the dcry gene alters the light-induced phase delay in the locomotor activity rhythms of flies. CONCLUSION: These results suggest that DCRY is a circadian photoreceptor and that its expression is regulated by circadian clock genes.

timrit Lengthens circadian period in a temperature-dependent manner through suppression of PERIOD protein cycling and nuclear localization.

A fundamental feature of circadian clocks is temperature compensation of period. The free-running period of ritsu (timrit) (a novel allele of timeless [tim]) mutants is drastically lengthened in a temperature-dependent manner. PER and TIM protein levels become lower in timrit mutants as temperature becomes higher. This mutation reduces per mRNA but not tim mRNA abundance. PER constitutively driven by the rhodopsin1 promoter is lowered in rit mutants, indicating that timrit mainly affects the per feedback loop at a posttranscriptional level. An excess of per+ gene dosage can ameliorate all rit phenotypes, including the weak nuclear localization of PER, suggesting that timrit affects circadian rhythms by reducing PER abundance and its subsequent transportation into nuclei as temperature increases.

Apoptosis of the intestinal principal cells of Xenopus larvae exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

In our previous work using paraffin-embedded sections, we determined that Xenopus larvae exposed to 200 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 5 days from shortly after fertilization to the early larval stage showed a shortening of the digestive tract and a loss of mucosal epithelium cells due to exfoliation into the gut cavity. In the current study, we ultrastructurally examined the mucosal epithelium of the gut of TCDD-exposed Xenopus larvae 12 days after fertilization. Exfoliated cell structures at the villus tip and in the lumen were equipped with a microvillus portion and occasionally had terminal web-like structures seen by ultramicroscopy. As these exfoliated structures had nuclear fragments with condensed chromatin, they were considered to be apoptotic bodies derived from the principal cells of the epithelium. In addition, many membrane-bound cell fragments-identified as apoptotic bodies derived from the principal cells based on their ultrastructural features-were observed at the basal side of the mucosal epithelium. These apoptotic bodies were phagocytized and digested chiefly by the neighboring intact principal cells. No such cells and/or cell fragments showing apoptotic features were observed in the controls. Our observations indicate that marked apoptosis occurs in the intestinal principal cells of TCDD-exposed larvae, which may result in the shortening of the gut.

Acein-1, a novel angiotensin-I-converting enzyme inhibitory peptide isolated from tryptic hydrolysate of human plasma.

A novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated acein-1, was isolated from the tryptic hydrolysate of human plasma. Gel filtration and cation exchange chromatography were performed to purify this peptide, followed by reversed-phase gradient and isocratic high-performance liquid chromatography. Acein-1 was found to be a heptapeptide, Tyr-Leu-Tyr-Glu-Ile-Ala-Arg, corresponding to f(138-144) of human serum albumin. The synthetic heptapeptide, hexapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala, des-7R acein-1) and octapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala-Arg-Arg, acein-1R) showed dose-dependent inhibitions of ACE, and their IC50 values were 16 micromol/l, 500 micromol/l and 86 micromol/l, respectively. Acein-1 might be a non-competitive inhibitor, while acein-1R may be an uncompetitive inhibitor, as shown by Lineweaver-Burk plots.

Using postnatal age to determine test dates leads to misinterpretations when treatments alter gestation length: results from a collaborative behavioral teratology study in Japan.

A collaborative study was conducted by researchers from 18 laboratories that participated in the Behavioral Teratology Meeting in Japan. Pregnant Sprague-Dawley rats from four breeders received subcutaneous injections of nicotine (6 mg/kg body weight) from day 7 to day 20 of gestation. Results of preweaning tests were closely related to length of gestation, and prolonged gestation was seen in the nicotine group. The effects of nicotine were compared with and without the adjustment of the mean difference in gestational lengths. Without the adjustment (i.e., by employing assessment in terms of postnatal day) several perplexing results were obtained, indicating that the nicotine group developed more quickly than the control group on several preweaning tests. By employing the adjustment, these perplexing results disappeared, indicating that the nicotine group developed more slowly than the control group. The merit of employing gestational day (or postcoital age) as an alternative index is emphasized.

Atrial septal defect in cyanotic CL/Fr mice.

OBJECTIVE: It is widely known that some newborn CL/Fr mice with cleft lip and palate (CLP) also have cyanotic symptoms, which have been thought to depend on an atrial septal defect (ASD). In a previous study, we found that cyanotic mice tended to have more severe types of CLP. We hypothesize that the mechanical airway obstruction due to a poorly developed palatal shelf and unmoved tongue in CLP(+) mice might be related to the occurrence of cyanosis. The purpose of this study was to examine the relationships between ASD and cyanosis in CLP(+) newborns. METHOD: The newborn hearts from CLP(-), noncyanotic CLP(+), cyanotic CLP(+), CL/Fr mice and ICR mice were examined histologically, and the incidence and size of ASD was determined on neonatal day (ND) 0. In CLP(-) newborns, similar procedures were performed from ND 1 to ND 4. Furthermore, in CLP(+) newborns, development of the palatal shelf was examined. RESULTS: While all the ICR mice had a well-developed atrial septum, and the incidence of ASD was 0%, about 80% of CL/Fr mice had ASD, irrespective of the presence or absence of CLP and cyanosis. On ND 0, the septum primum was significantly shorter in cyanotic CLP(+) mice than in CLP(-) mice. It also tended to be shorter in CLP(+) mice than in CLP(-) mice. Between the cyanotics and noncyanotics, there were no significant differences in the incidences of ASD and the rate of septal development. In CLP(-) mice, the septum primum developed well later and no ASD was observed on ND 4. Cyanotic newborns had significantly less developed palatal shelves than did noncyanotics. CONCLUSIONS: Cyanosis may not be related to ASD and the rate of septal development, but may be related to the occurrence of CLP in this strain. Furthermore, we confirmed that some relationship exists between the development of the palatal shelf and cyanosis. The present study supports our hypothesis concerning the cause of cyanosis in CL/Fr mice.

Cell ablation by ectopic expression of cell death genes, ced-3 and Ice, in Drosophila.

We have developed a system for killing specific cells in Drosophila using ectopic expression of cell death genes. CED-3 and ICE (caspase-1) are proteins required for programmed cell death in the nematode Caenorhabditis elegans and in mammals, respectively. Our previous study has shown that both ced-3 and Ice can elicit cell death in Drosophila. By expressing ced-3 or Ice in several kinds of cells using a GAL4-UAS system and examining the resulting morphological defects, we show that these abnormalities are thought to be caused by the action of ced-3 or Ice genes. As cells are killed by apoptosis in our system, we could eliminate the possibility of harmful effects on the neighboring cells. Our system provides an alternative and novel cell ablation method to elucidate mechanisms of cell differentiation and cell-cell interactions during development in Drosophila.

Apoptotic cell death of erythrocytes in Xenopus larvae exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Xenopus embryos were exposed to 200 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 5 days from the 2- to 8-cell stage of cleavage to the early larval stage. Larvae that developed generalized edema were collected at 7 days after the end of TCDD exposure for light and electron microscopic studies. Erythrocytes in the peripheral blood of the edematous larvae were examined. Between 0.3 and 33.9% of identifiable erythrocytes of exposed larvae had dilated perinuclear cisternae. Furthermore, some had extremely condensed nuclear chromatin usually coalesced against 1 pole of the nuclear membrane and overall compacted cytoplasm. The erythrocytes showing nuclear condensation were phagocytosed by macrophages. These features are typical of cells undergoing apoptosis. Anemia is 1 symptom of TCDD toxicity in various animal species, including mammals. In this study, we demonstrate that TCDD induces apoptotic cell death in circulating erythrocytes of Xenopus larvae, which may be 1 cause of anemia in this species.

Targeted expression of ced-3 and Ice induces programmed cell death in Drosophila.

CED-3 is a cysteine protease required for programmed cell death in the nematode, Caenorhabditis elegans, and shares a sequence similarity with mammalian ICE (interleukin-1beta converting enzyme) family proteases. Both CED-3 and ICE family proteases can induce programmed cell death in mammalian cells. Structural and functional similarities between CED-3 and ICE family proteases indicate that the mechanism of cell death is evolutionarily conserved, suggesting the presence of a similar mechanism involving CED-3/ICE-like proteases in Drosophila. Here we determined whether CED-3 or ICE functions to induce programmed cell death in Drosophila. We have generated transformant lines in which ced-3 or Ice is ectopically expressed using the GAL4-UAS system. Expression of CED-3 and ICE can elicit cell death in Drosophila and the cell death was blocked by coexpressing the p35 gene which encodes a viral inhibitor of CED-3/ICE proteases. Results support the idea that the mechanism of programmed cell death controlled by CED-3/ICE is conserved among widely divergent animal species including Drosophila, and the system described provides a tool to dissect cell death mechanism downstream of CED-3/ICE proteases.