Psychological and physical reactions on children after the Hanshin-Awaji earthquake disaster

Children who experienced the Hanshin-Awaji Earthquake Disaster were followed to ascertain how the psychological and physical reactions after this disaster changed. Changes observed in the symptoms of children at one and two years after the earthquake were compared between those who had lived in severely damaged area (level 7 on the Japan Meteorological Agency intensity scale) and those who had lived in mildly damaged area (less than 5 on the same scale). The survey was conducted using a questionnaire filled out by the children's parents. Two years after the earthquake, the children had returned to normal in terms of their physical conditions, even in the severely damaged area. However, symptoms of PTSD (Post-Traumatic Stress Disorder) such as persistent reexperiencing, persistent avoidance, and increased arousal were significantly more frequently found among children from the severely damaged area than among those from the mildly damaged area. To evaluate the psychological and physical reactions after the disaster is very important in order to support the children when large-scale disasters occur.

ESR investigation on the breather mode and the spinon-breather dynamical crossover in Cu benzoate

A "breather excitation" is observed directly by electron spin resonance in the quantum spin chain Cu benzoate, in which an unexpected field-induced gap has recently been found. The nonlinear field dependence of the resonance field agrees well with the formula based on a quantum sine-Gordon model. The power-law temperature dependence of the linewidth is observed in the gapless spinon regime while the width decreases exponentially for the gapped breather regime. In the intermediate range, a distinct anomaly is found, which is the manifestation of "the spinon-breather dynamical crossover."

Evolution of the eukaryotic translation termination system: origins of release factors

Accurate translation termination is essential for cell viability. In eukaryotes, this process is strictly maintained by two proteins, eukaryotic release factor 1 (eRF1), which recognizes all stop codons and hydrolyzes peptidyl-tRNA, and eukaryotic release factor 3 (eRF3), which is an elongation factor 1alpha (EF-1alpha) homolog stimulating eRF1 activity. To retrace the evolution of this core system, we cloned and sequenced the eRF3 genes from Trichomonas vaginalis (Parabasalia) and Giardia lamblia (Diplomonada), which are generally thought to be "early-diverging eukaryotes," as well as those from two ciliates (Oxytricha trifallax and Euplotes aediculatus). We also determined the sequence of the eRF1 gene for G. lamblia. Surprisingly, the G. lamblia eRF3 appears to have only one domain, corresponding to EF-1alpha, while other eRF3s (including the T. vaginalis protein) have an additional N-terminal domain, of 66-411 amino acids. Considering this novel eRF3 structure and our extensive phylogenetic analyses, we suggest that (1) the current translation termination system in eukaryotes evolved from the archaea-like version, (2) eRF3 was introduced into the system prior to the divergence of extant eukaryotes, including G. lamblia, and (3) G. lamblia might be the first eukaryotic branch among the organisms considered.

The effects of plasma fentanyl concentrations on propofol requirement, emergence from anesthesia, and postoperative analgesia in propofol-nitrous oxide anesthesia

To determine the effects of plasma fentanyl concentrations on intraoperative propofol requirements, emergence from anesthesia, and relief of postoperative pain, we studied 60 ASA physical status I and II patients undergoing spine fusion. The patients were randomly assigned to four study groups according to the expected intraoperative plasma fentanyl concentrations. Group I received an infusion of saline, and Groups II, III, and IV received fentanyl infusions to maintain the blood levels at 1.5, 3.0, and 4.5 ng/mL, respectively. An infusion rate of propofol was adjusted to keep the mean arterial pressure within 15% of the control value. Inspired nitrous oxide concentrations were maintained at 67%. The following were investigated in each group: 1) an average propofol infusion rate, 2) time to spontaneous eye opening and recovery of orientation (name, date, and place), and 3) total dose of fentanyl used for 24 h after admission to the postanesthetic care unit. Average propofol infusion rates were 10.1 +/- 2.5 (mean +/- SD), 7.5 +/- 1.2, 5.7 +/- 1.1, and 4.9 +/- 1.2 mg. kg(-1). h(-1), in Groups I, II, III, and IV, respectively. Groups receiving fentanyl infusion had significantly smaller infusion rates of propofol (P < 0.01) than the group receiving saline. Among the three fentanyl infusion groups, Group II (P < 0.01) had more than Groups III and IV. The time to spontaneous eye opening and the recovery of orientation were directly related to plasma fentanyl concentrations. The plasma fentanyl levels between Groups III and IV were the same. The total amount of IV patient-controlled analgesia fentanyl during postoperative 24 h increased significantly when the order of plasma fentanyl concentrations was reversed, 913.1 +/- 58.4, 553.4 +/- 129, 222.7 +/- 73.4, and 135.1 +/- 69.5 microg in Groups I, II, III, and IV, respectively. These results suggest that the addition of fentanyl infusions had ceiling effects that reduce the intraoperative propofol requirements according to the plasma fentanyl concentrations. The ceiling effect was demonstrated in the recovery of consciousness but not in the fentanyl requirements for postoperative analgesia.

IMPLICATIONS

The addition of fentanyl, a potent opioid, reduced the intraoperative requirement of propofol, an IV anesthetic, in the order of the plasma fentanyl concentrations. The ceiling effects of fentanyl were demonstrated in the reduction of propofol requirements and recovery of consciousness but not in the fentanyl requirements for postoperative analgesia.

Oxidized galectin-1 promotes axonal regeneration in peripheral nerves but does not possess lectin properties

Galectin-1 has recently been identified as a factor that regulates initial axonal growth in peripheral nerves after axotomy. Although galectin-1 is a well-known beta-galactoside-binding lectin, its potential to promote axonal regeneration as a lectin has not been reported. It is essential that the process of initial repair in peripheral nerves after axotomy is well clarified. We therefore undertook to investigate the relation between the structure and axonal regeneration-promoting activity of galectin-1. Recombinant human galectin-1 secreted into the culture supernatant of transfected COS1 cells (rhGAL-1/COS1) was purified under nonreducing conditions and subjected to structural analysis. Mass spectrometric analysis of peptide fragments from rhGAL-1/COS1 revealed that the secreted protein exists as an oxidized form containing three intramolecular disulfide bonds (Cys2-Cys130, Cys16-Cys88 and Cys42-Cys60). Recombinant human galectin-1 (rhGAL-1) and a galectin-1 mutant in which all six cysteine residues were replaced by serine (CSGAL-1) were expressed in and purified from Escherichia coli for further analysis; the purified rhGAL-1 was subjected to oxidation, which induced the same pattern of disulfide linkages as that observed in rhGAL-1/COS1. Oxidized rhGAL-1 enhanced axonal regeneration from the transected nerve sites of adult rat dorsal root ganglion explants with associated nerve stumps (5.0-5000 pg. mL-1), but it lacked lectin activity. In contrast, CSGAL-1 induced hemagglutination of rabbit erythrocytes but lacked axonal regeneration-promoting activity. These results indicate that galectin-1 promotes axonal regeneration only in the oxidized form containing three intramolecular disulfide bonds, not in the reduced form which exhibits lectin activity.

Genomic differences in Streptococcus pyogenes serotype M3 between recent isolates associated with toxic shock-like syndrome and past clinical isolates

Genomic differences among past Streptococcus pyogenes serotype M3 strains isolated in 1973 and before from patients with streptococcal pharyngitis, recent (1990s) serotype M3 clinical isolates from patients with pharyngitis, and recent M3 isolates from patients with toxic shock-like syndrome were investigated by restriction landmark genomic scanning and by modified random-amplified polymorphic DNA-polymerase chain reaction. Similar polymorphic DNA fragments were identified between the older M3 isolates and the recent isolates; also, the recent M3 clinical isolates from patients with pharyngitis were genetically indistinguishable, by the methods used, from the M3 isolates of patients with toxic shock-like syndrome. Although nucleotide sequences of these regions showed no apparent homology with known virulence factors, the DNA fragments could distinguish the recent M3 strains from the past strains. These results suggested that the recent strains have emerged because of genetic divergence.

Phylogenetic analysis of diatom coxI genes and implications of a fluctuating GC content on mitochondrial genetic code evolution

In order to address the relationships among diatom groups and to investigate possible changes in their mitochondrial (mt) genetic codes, we have analyzed a 1.1-kb region of the cytochrome c oxidase subunit I (coxI) gene from eight diverse diatom species. A phylogenetic analysis of these coxI sequences including representative species of the Phaeophyta, Xanthophyta, Eustigmatophyta and Haptophyta showed that the diatoms (Bacillariophyta) formed a well-supported monophyletic group. Of the eight species investigated, four have been classified together as radial centric diatoms based on morphology. However, in our coxI tree, the two radial centrics belonging to the order Thlassiosirales (Skeletonema costatum and Thalassiosira nordenskioldii) were placed as the sister group to the multipolar centric diatoms, while the other two radial centrics (Melosira ambigua and Rhizosolenia setigera) were in another clade. Also, in two species of the Tharassiosirales we found UGA codons that occur at conserved tryptophan (Trp) sites in the coxI sequences, strongly indicating that UGA codes for Trp in these diatoms. No evidence of a deviant genetic code was detected in the other analyzed diatom species. There was no apparent relationship between the nucleotide third-position GC content of mtDNA (based on the sequenced coxI region) and the presence of a deviant genetic code.

Proteomic approach to the identification of cell membrane proteins

The expression of plasma membrane proteins in human monocyte-derived U937 cells was examined by cell disruption and isolation of microsomal fractions. Two alternative procedures for cell disruption, Dounce homogenization and nitrogen cavitation, were compared. Cell homogenization and sequential centrifugation resulted in an approximately fivefold enrichment of plasma membrane proteins in the microsomal fraction. However, identification of 30 such apparently enriched proteins by two-dimensional (2-D) electrophoresis, proteolytic digestion, and mass spectrometry revealed that only eight were plasma membrane proteins, the remaining 22 being contaminants. In contrast, nitrogen cavitation followed by sequential centrifugation and solubilization of proteins with sodium dodecyl sulfate (SDS) and 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate (CHAPS) detergent yielded subcellular fractions, including microsomes, that showed little overlap in constituent proteins as revealed by 2-D electrophoresis. These results highlight the importance of obtaining pure plasma membranes and complete solubilization of membrane proteins for proteomic analysis.

Galectin-1 regulates initial axonal growth in peripheral nerves after axotomy

The signals that prompt the axons to send out processes in peripheral nerves after axotomy are not well understood. Here, we report that galectin-1 can play an important role in this initial stage. We developed an in vitro nerve regeneration model that allows us to monitor the initial axon and support cell outgrowth from the proximal nerve stump, which is comparable to the initial stages of nerve repair. We isolated a factor secreted from COS1 cells that enhanced axonal regeneration, and we identified the factor as galectin-1. Recombinant human galectin-1 (rhGAL-1) showed the same activity at low concentrations (50 pg/ml) that are two orders of magnitude lower than those of lectin activity. A similarly low concentration was also effective in in vivo experiments of axonal regeneration with migrating reactive Schwann cells to a grafted silicone tube after transection of adult rat peripheral nerve. Moreover, the application of functional anti-rhGAL-1 antibody strongly inhibited the regeneration in vivo as well as in vitro. The same effect of rhGAL-1 was confirmed in crush/freeze experiments of the adult mouse sciatic nerve. Because galectin-1 is expressed in the regenerating sciatic nerves as well as in both sensory neurons and motor neurons, we suggest that galectin-1 may regulate initial repair after axotomy. This high activity of the factor applied under nonreducing conditions suggests that galectin-1 may work as a cytokine, not as a lectin.

A study of anti-carbonic anhydrase II antibodies in rheumatic autoimmune diseases

Autoantibodies to human carbonic anhydrase II (CAII) were screened by ELISA in 109 sera from Asian Japanese patients with systemic lupus erythematosus (SLE), primary Sjögren's syndrome (Sjs), progressive systemic sclerosis (PSS) and dermatomyositis (DM). Anti-CAII antibodies were positive in 24.1% of SLE, 20.0% of primary Sjs, 16.7% of PSS and 25.0% of DM. On the other hand, sera from atopic dermatitis, bullous pemphigoid and psoriasis patients showed no activity for anti-CAII antibodies. CAII could be a common exonuclear autoantigen in subsets of rheumatic autoimmune diseases.

Floricultural traits and transposable elements in the Japanese and common morning glories

The Japanese morning glory has an extensive history of genetic studies and over 200 different spontaneous mutant lines have been described. Of these, we identified that two mutable alleles, flecked and speckled, for flower variegations are caused by integration of transposable elements, belonging to the En/Spm family, into the DFR-B and CHI genes for flower pigmentation, respectively. The mutable flaked allele of the common morning glory bearing variegated flowers is caused by insertion of a new transposable element, Tip100, into one of the CHS genes for pigmentation and that Tip100 belongs to the Ac/Ds family. These results are discussed with regard to spontaneous transposon mutagenesis and generation of floricultural traits of morning glories.

Capture of a genomic HMG domain sequence by the En/Spm-related transposable element Tpn1 in the Japanese morning glory

The non-autonomous transposable element Tpn1 from the Japanese morning glory is an En/Spm-related DNA element found in the second intron of the DFR-B gene for flower pigmentation in the mutable line flecked, which shows variegation for flower color. It carries a genomic DNA segment containing at least four exon sequences encoding part of a HMG-box sequence. Spliced hybrid transcripts containing the DFR-B exon(s) and the HMG exons in Tpn1 were detected in the flower buds of the flecked line, and they were polyadenylated within Tpn1. Thus, Tpn1 can be regarded as a specialized transducing transposon carrying a part of the genomic sequence for a HMG box. The possible implications of the finding for evolution are discussed.

The cost-effectiveness of methohexital versus propofol for sedation during monitored anesthesia care

We designed this study to test the hypothesis that methohexital is a cost-effective alternative to propofol for sedation during local anesthesia. Sixty consenting women undergoing breast biopsy procedures under local anesthesia were randomly assigned to receive an infusion of either propofol (50 microg x kg(-1) x min(-1)) or methohexital (40 microg x kg(-1) x min(-1)). The sedative infusion rate was titrated to maintain an observer's assessment of alertness/sedation (OAA/S) score of 3 (with 1 = awake/alert to 5 = asleep). Fentanyl 25 microg i.v. was administered as a "rescue" analgesic during the operation. We assessed the level of sedation (OAA/S score), vital signs, time to achieve an OAA/S score of 3 at the onset and a score of 1 after discontinuing the infusion, discharge times, perioperative side effects, and patient satisfaction. The direct cost of methohexital was lower than that of propofol, based on the milligram dosage infused during the operation. The sedative onset (to achieve an OAA/S score of 3) and the recovery (to return to an OAA/S score of 1) times, as well as discharge times, did not differ between the two groups. Patients receiving methohexital had a significantly lower incidence of pain on initial injection compared with those receiving propofol (10% vs 23%). Because the use of methohexital (29.4 +/- 2.7 microg x kg(-1) x min(-1)) for sedation during breast biopsy procedures has a similar efficacy and recovery profile to that of propofol (36.8 +/- 15.9 microg x kg(-1) x min(-1)) and is less costly based on the amount infused, it seems to be a cost-effective alternative to propofol for sedation during local anesthesia. However, when the cost of the drug infused and drug wasted was calculated, there was no difference in the overall drug cost.

IMPLICATIONS

When administered to maintain a stable level of sedation during local anesthesia, methohexital is an acceptable alternative to propofol. However, the overall drug costs were similar with the two drugs.

Absence of R1066X mutation in six Japanese patients with Dubin-Johnson syndrome

The Dubin-Johnson syndrome (DJS) is a rare autosomal recessive liver disease characterized by chronic conjugated hyperbilirubinemia. The phenotype of this syndrome is thought to be caused by the impaired expression of the canalicular multispecific organic anion transporter (cMOAT), which transports non-bile salt organic anions into the bile. Recently, a mutation from arginine (Arg) to stop-codon at codon 1066 in the cMOAT gene has been reported in one Caucasian patient with DJS. In this study, we investigated whether this mutation is found in Japanese patients with DJS. Genomic DNAs were extracted from the leukocytes of six Japanese patients and the fragments spanning codon 1066 were amplified by polymerase-chain reaction. The digest of the amplified fragments with a restriction enzyme, Taql, demonstrated that all of six patients did not exhibit an R1066X mutation. No mutation at Arg1066 was also confirmed by direct sequencing of the amplified products. These findings suggested that this R1066X mutation was not a major mutation in Japanese patients with DJS. Further investigation will be required in an attempt to search other mutations in cMOAT gene in Japanese patients with DJS.

Remifentanil administration during monitored anesthesia care: are intermittent boluses an effective alternative to a continuous infusion?

This randomized, double-blind study was designed to evaluate the analgesic effectiveness and respiratory stability of remifentanil when administered as intermittent bolus injections, a variable-rate infusion, or a combination of a constant basal infusion supplemented with intermittent boluses during monitored anesthesia care (MAC). Forty-five patients undergoing extracorporeal shock wave lithotripsy (ESWL) procedures were randomly assigned to one of the three modes of remifentanil administration. All patients received midazolam 2 mg i.v., followed by a propofol infusion at 50 microg x kg(-1) x min(-1). Two minutes before administering a series of test shock waves: Group I received a remifentanil infusion of 0.1 microg x kg(-1) x min(-1), and a saline bolus (5 mL); Group II received a saline infusion and a remifentanil bolus (25 microg in 5 mL); and Group III received a remifentanil infusion of 0.05 microg x kg(-1) x min(-1), and a remifentanil bolus (12.5 microg in 5 mL). The average pain intensity was scored on an 11-point scale, with 0 = no pain to 10 = severe pain. During the ESWL procedure, pain was treated by increasing the study drug infusion rate by 25%-50% and administering 5-mL bolus injections of the study medication in Groups I (saline) and II (remifentanil 25 microg). In Group III, intermittent 5-mL boluses (remifentanil 12.5 microg) were administered as needed. Patients in Groups II and III reported lower pain scores in response to the test shocks. Significantly more remifentanil was administered in Group I (379 +/- 207 microg) than in Group II (201 +/- 136 microg). However, more interventions were required for the treatment of intraoperative pain in the intermittent bolus group (Group II). When remifentanil is administered as the analgesic component of a MAC technique, these data support the use of intermittent bolus doses (12.5-25 microg) alone or in combination with a basal infusion (0.05 microg x kg(-1) x min(-1)) as alternatives to a variable-rate continuous infusion.

IMPLICATIONS

In this study, three different modes of remifentanil administration were used during monitored anesthesia care for extracorporeal shock wave lithotripsy procedures. These results suggest that using intermittent bolus injections of remifentanil (25 microg) or a continuous infusion (0.05 microg x kg(-1) x min(-1)) supplemented with intermittent bolus (12.5 microg) injections may be more effective than a variable-rate infusion of remifentanil during propofol sedation.

Genomic organization of the genes encoding dihydroflavonol 4-reductase for flower pigmentation in the Japanese and common morning glories

Genomic DNA segments (approximately 17kb) containing three DFR genes in the Japanese and common morning glories were sequenced. The three DFR genes in both plants were found to be arranged in a tandem array, and all of them comprised six exons with identical intron positions. Their DFR-B genes carrying longer introns than the DFR-A and DFR-C genes were expressed extensively in the young buds of pigmented flowers, and the transcription starting site for the DFR-B mRNA of the Japanese morning glory was determined. The DFR-B gene of the common morning glory was expressed considerably in stems, moderately in sepals and leaves, whereas the DFR-A and DFR-C genes of the same plant were expressed scarcely but significantly in the young flower buds and stems. Several novel mobile element-like sequences of around 200bp were found in the genomic DFR regions. A phylogenetic tree indicated that each DFR gene in the Japanese morning glory is most closely related to the corresponding DFR gene in the common morning glory, and that the DFR-B gene is the most diversified gene among the three DFR genes. These structural and functional features of the DFR genes and their evolutionary implications are discussed.

A new low density lipoprotein receptor related protein, LRP5, is expressed in hepatocytes and adrenal cortex, and recognizes apolipoprotein E

The isolation and characterization of rabbit and human cDNAs revealed a new low density lipoprotein receptor (LDLR)-related protein (LRP) designated as LRP5. Human LRP5 cDNA encodes a 1, 616-amino acid type I membrane-like protein with three ligand binding repeats in its extracellular region. LDLR-deficient cells transduced by recombinant adenovirus containing human LRP5 exhibited increased binding of apolipoprotein E (apoE)-enriched beta-migrating very low density lipoprotein. Northern blotting and in situ hybridization revealed a high level of LRP5 expression in hepatocytes and the adrenal gland cortex. In LDLR-deficient Watanabe heritable hyperlipidemic rabbits, LRP5 mRNA was increased in the liver and accumulated in cholesterol-laden foam cells of atherosclerotic lesions.

Directionally evolving genetic code: the UGA codon from stop to tryptophan in mitochondria

For the comprehensive analyses of deviant codes in protistan mitochondria (mt), we sequenced about a 1.1-kb region of a mitochondrial (mt) gene, the cytochrome c oxidase subunit I (coxI) in two chlorarachniophytes, the filose amoeba Euglypha rotunda, the cryptomonad Cryptomonas ovata, the prymnesiophyte (haptophyte) Diacronema vlkianum (Pavlovales), and the diatom Melosira ambigua. As a result of this analysis, we noticed that the UGA codon is assigned to tryptophan (Trp) instead of being a signal for translational termination in two chlorarachniophytes and in E. rotunda. The same type of deviant code was reported previously in animals, fungi, ciliates, kinetoplastids, Chondrus crispus (a red alga), Acanthamoeba castellanii (an amoeboid protozoon), and three of the four prymnesiophyte orders with the exception of the Pavlovales. A phylogenetic analysis based on the COXI sequences of 56 eukaryotes indicated that the organisms bearing the modified code, UGA for Trp, are not monophyletic. Based on these studies, we propose that the ancestral mitochondrion was bearing the universal genetic code and subsequently reassigned the codon to Trp independently, at least in the lineage of ciliates, kinetoplastids, rhodophytes, prymnesiophytes, and fungi. We also discuss how this codon was directionally captured by Trp tRNA.

Activation of Proalpha2(I) collagen promoter during hepatic fibrogenesis in transgenic mice

We previously identified the promoter sequence that is essential for basal and TGF-beta-stimulated transcription of alpha2(I) collagen gene (COL1A2). In the present study, we examined whether the promoter is activated during hepatic fibrogenesis by utilizing transgenic mice harboring the COL1A2 upstream sequence. Intraperitoneal CCl4 administration activated the -17 kb COL1A2 promoter more than 10-fold, whereas partial hepatectomy resulted in no significant change in the promoter activity. The non-parenchymal cell fraction, but not parenchymal hepatocytes, isolated from mice harboring the -313 COL1A2 promoter linked to a beta-galactosidase reporter gene contained large amounts of beta-galactosidase and endogenous COL1A2 mRNAs. beta-galactosidase activity in the cells from CCl4-treated mice was significantly higher than in those from untreated animals. These results indicated that different molecular mechanisms control COL1A2 transcription in CCl4-induced liver injury/fibrosis and physiological regeneration after partial hepatectomy, and that the -313 COL1A2 promoter is activated in a cell type-specific manner during hepatic fibrogenesis.

Presence of Streptococcus anginosus DNA in esophageal cancer, dysplasia of esophagus, and gastric cancer

We recently reported cloning of Streptococcus anginosus (S. anginosus) DNA fragments containing the 16S ribosomal gene from DNA samples of surgical specimens of gastric cancers. To investigate the specificity of S. anginosus infection, Southern blot analysis with S. anginosus 16S ribosomal DNA probe and PCR analysis with S. anginosus-specific primers were performed in DNA samples prepared from 15 esophageal cancers, 43 gastric cancers, 16 lung cancers, 10 cervical cancers, 14 renal cell carcinomas, 10 colorectal cancers, and 19 bladder cancers. We frequently found S. anginosus DNA sequences in DNA samples from esophageal cancer and gastric cancer tissues, as well as in those from dysplasia of the esophagus of esophageal cancer patients. No S. anginosus DNA bands were detected by Southern blot analysis on DNAs from the noncancerous portions of the esophagus or the stomach. By PCR analysis with 35 cycles, only 7% of the noncancerous portion of the esophagus was shown to contain S. anginosus sequences. No S. anginosus sequences were found in DNAs from cancers in lung, cervix, and kidney, but they were found in 1 of 10 colon cancers.

Distinctive origins of group I introns found in the COXI genes of three gree algae

Upon surveying the cytochrome c oxidase subunit I (COXI) gene of green algae, we found group I introns in three species of algae, Chlorella vulgaris (Cv), Scenedesmus quadricauda (Sq) and Protosiphon botryoides (Pb). The comparative analysis of these nucleotide sequences and their secondary structures revealed that the introns of Cv, Sq, and Pb belong to groups IB1, ID, and IB2, respectively. Each of the three introns contained an open reading frame (ORF) that showed a similarity to the sequence of the LAGLIDADG endonuclease family. However, each of the intronic ORFs in Sq and Pb had a discontinuity in the middle of' the sequences coding for the LAGLIDADG endonuclease. Either of the two ORFs could be restored to a sequence homologous to the LAGLIDADG endonuclease by the insertion of a nucleotide in the appropriate position. In Sq, a putative pseudo-knot structure was detected in the intronic ORF This suggests the occurrence of a ribosomal frameshift in the translation of the ORF. because such pseudo-knot structures are common in viral ORFs employing a (-1) ribosomal frameshift. In the phylogenetic tree that was inferred from the amino acid sequences of algal and non-algal intronic ORFs, the three algal ORFs did not make a cluster, but were scattered throughout the tree. In addition. each of the three algal ORFs showed a close relationship to the ORFs of non-algal introns that were inserted at the corresponding site of the COX] gene, suggesting distinctive origins of the three algal introns via independent horizontal transfers.