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Prolyl endopeptidase (EC3.4.21.26) has been considered a unique intracellular enzyme catalyzing internal peptide bond hydrolysis of Pro-X. In this study, the distribution of prolyl endopeptidase activity and its mRNA was investigated in the follicles of porcine ovary. Both follicular fluid and granulosa cell fractions from small follicles showed higher activity than those from large follicles. Molecular cloning and Northern blot analysis suggested that only one species of prolyl endopeptidase gene was expressed in the ovary. In addition, in situ hybridization study revealed that the prolyl endopeptidase mRNA expresssion was more noticeable in the granulosa cell layers of small ovarian follicles than in those of large follicles, suggesting its importance in the early stage of follicular development.

The time evolution of three-dimensional hydromagnetic waves in a nonideal magnetohydrodynamic (MHD) plasma is investigated. Two types of exact time-dependent wave solutions of the nonlinear resistive and dissipative MHD equations are found. One solution shows a damped Alfven wave and the other one shows a magnetically compressional wave with the magnetic and velocity fields having different damping times. It is shown that in the asymptotic limit, t → ∞, the plasma relaxes toward the equilibrium state with no magnetic field and constant (for the former solution) or sheared (for the latter solution) velocity.

The areal distribution, stand structure and biomass of pure stands of Elodea nuttallii, an alien species of water weed invading Lake Biwa since 1961, were studied with emphasis on the remarkable yearly fluctuation in its biomass. The total area covered by the Elodea community was estimated at 895 ha, based on a complete lake survey in 1990 using sonar detection along a number of line transects. Underwater biomass samplings were carried out at two different depths in the northernmost part of the lake during two successive years, representing a light crop year (1988) and a heavy crop year (1989). The maximum biomass and stem density at the shallower site (depth 3 m) in 1989 amounted to 723g dry wt. m-2 and 4, 960 stems m-2, respectively. Those in 1988 were only 68% and 60% of the corresponding values of 1989. Both biomass and stem density decreased at the deeper sites (depth 5m), with the latter remaining fairly constant in both years. A comparison of environmental factors between light and heavy crop years indicated that a mild winter with a minimum monthly temperature above 8°C combined with sufficient sunshine in early spring favored the growth of overwintering plants from which new shoots were produced vegetatively. This resulted in greater biomass production in the following season.

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was performed as a diagnostic procedure for two pediatric patients with intra-abdominal tumors. Case 1 was an 8-year-old boy with a huge tumor in the portal-hepatic region. Case 2 was a 17-year-old girl with a history of diabetes and recurrent relapse of Burkitt lymphoma, who had a newly developing tumor in the pancreatic body. In both cases, EUS-FNA was performed as a less invasive diagnostic procedure than open biopsy or total resection of the tumor. Tumor cells were determined to be of the B cell lineage by flow cytometric and immunostaining analyses. Both cases were diagnosed as having Burkitt lymphoma based on detection of IgH/C-MYC translocation by FISH. The aspiration was successfully conducted without severe complications, and both patients were immediately given chemotherapy. EUS-FNA is a safe and minimally invasive procedure with high diagnostic value for pediatric cases with intra-abdominal tumors.

The time evolution of hydromagnetic waves in a nonideal magnetohydrodynamic (MHD) plasma is investigated. Exact time-dependent wave solutions of the nonlinear resistive and dissipative MHD equations for a plane geometry are presented to show that the magnetic field and the velocity have different damping times and that in the asymptotic limit t → ∞ the plasma relaxes toward the equilibrium state with no magnetic and velocity fields.

PCR surveillance of the rstR genes of CTX phages in Vibrio cholerae O1 and O139 showed no relationship between the incidence of disease and changes in the rstR but showed variations in their presence in O1 and O139 strains and the occurrence of multiple types in a few strains.

The coppice stands under the climatic conditions of Warmth Index (WI)≧85°C·month, and Coldness Index (CI)≦−10°C·month could be classified into aQuercus serrata type andCarpinus types at a heavy snowfall climate region of central Japan. The latter types tended to be more distributed on steeper slopes rather than the former. An analysis of tree forms and growth rates of species could reveal the characteristic of this habitat and vegetation type. The growth rates of stem diameter of dominant species on a gentle slope were higher than ones on a steep slope. However, the dominant species on the steeper slope had plasticity to basal bend with sustentacular roots, which is one form of tolerance of heavy snowfall on steep slopes. Average mortality during 14 years was 26%, irrespective of the gradient of a slope. More than one-third of dead shoots were induced by direct damage, while cracked or broken pieces of a stem were from heavy snowfall. The shoot density at smaller diameter classes tended to be higher at a stand having high horizontal variance of canopy surface caused by basal bend of big shoots. A frequency distribution function of individual tree weight (w), f(w)=pw−3/2, could be obtained at each coppice stand by statistical analysis. The value of a parameter p, a packing factor, tended to be higher at stands on steeper slopes consisting of largely bent shoots and was constant irrespective of the growth.

Coli surface antigen 6 (CS6) is one of the most prevalent colonization factors among enterotoxigenic Escherichia coli (ETEC) isolated in developing countries. Although it is known that CS6 is encoded by a plasmid, there are no reports on the sequence analysis of the CS6-encoding plasmid or genes exhibiting similar behavior to CS6. Here, we report the isolation of the CS6-encoding plasmid, pCss165Kan, from 4266 ΔcssB::kanamycin (Km) and its complete nucleotide sequence. This plasmid consisted of 165,311bp and 222 predicted coding sequences. Remarkably, there were many insertion sequence (IS) elements, which comprised 24.4% of the entire sequence. Virulence-associated genes such as heat-stable enterotoxin, homologues of ATP-binding cassette transporter in enteroaggregative E. coli (EAEC), and ETEC autotransporter A were also present, although the ETEC autotransporter A gene was disrupted by the integration of IS629. We found that 2 transcriptional regulators belonging to the AraC family were not involved in CS6 expression. Interestingly, pCss165 had conjugative transfer genes, as well as 3 toxin-antitoxin systems that potentially exclude other plasmid-free host bacteria. These genes might be involved in the prevalence of CS6 among ETEC isolates.

Enterotoxigenic Escherichia coli (ETEC) expressing the colonization factor CS6 is widespread in many developing countries, including India. The different allelic variants of CS6, caused by point mutations in its structural genes, cssA and cssB , are designated AIBI, AIIBII, AIIIBI, AIBII, and AIIIBII. A simple, reliable, and specific m ismatch a mplification m utation a ssay based on real-time quantitative PCR (MAMA-qPCR) was developed for the first time for the detection of CS6-expressing ETEC, along with the identification of allelic variations. The assay was based on mismatched nucleotide incorporation at the penultimate base at the 3′ ends of the reverse primers specific for cssA and cssB and was validated using 38 CS6-expressing ETEC isolates. This strategy was effective in detecting all the alleles containing single-nucleotide polymorphisms. Using MAMA-qPCR, we also tested CS6 allelic variants in 145 ETEC isolates from children with acute diarrhea and asymptomatic infections, with the latter serving as controls. We observed that the AIBI and AIIIBI allelic variants were mostly associated with cases rather than controls, whereas the AIIBII variants were detected mostly in controls. In addition, the AIBI and AIIIBI alleles were frequently associated with ETEC harboring the heat-stable toxin gene ( est ) alone or with the heat-labile toxin gene ( elt ), whereas the AIIBII allele was predominant in ETEC isolates harboring the elt gene. This study may help in understanding the association of allelic variants in CS6-expressing ETEC with the clinical features of diarrhea, as well as in ETEC vaccine studies.

The propagation of nonlinear hydromagnetic waves in a highly conducting, self‐gravitating fluid in a spherical geometry, subject to the convective forces produced by a radial temperature gradient, is treated in a Boussinesq approximation. Exact wave solutions of the nonlinear magnetohydrodynamic equations (in the Boussinesq approximation) in the presence of convective forces are obtained for the toroidal velocity and magnetic fields. The solution represents waves propagating along the mean magnetic field with the velocity depending on the mean magnetic (or velocity) field strength and the strength of stratification, under the influence of the azimuthal magnetic and velocity fields and convective forces. The solutions may be applicable to the hydromagnetic waves in the Earth’s core and the solar convection zone.

Follipsin, an enzyme that accumulates in the follicular fluid of porcine ovaries during follicular maturation, was purified to apparent homogeneity. The purified enzyme consists of two different polypeptide chains having M(r) = 45,000 and 32,000 each, associated covalently. The enzyme activity was strongly inhibited by diisopropyl fluorophosphate, benzamidine, leupeptin, and antipain, indicating that follipsin is a serine proteinase. Using synthetic peptide substrates containing 4-methylcoumaryl-7-amide, follipsin was shown to preferentially hydrolyze Arg-X bonds but not Lys-X bonds. The NH2-terminal amino acid sequences of the 45- and 32-kDa polypeptides were highly homologous with those of the heavy and light chains, respectively, of human plasma kallikrein and human factor XIa. Immunological analyses and substrate specificity studies, together with other existing evidence, indicated that follipsin is distinct from kallikrein and factor XIa, thus being a novel type of serine proteinase. Follipsin is immunohistochemically localized in follicular fluid as well as in stroma cells of porcine ovaries. The results strongly suggest that follipsin originates from interstitial cells of the ovarian stroma.

Optic morphology (Om) mutations in Drosophila ananassae map to at least 22 loci scattered throughout the genome. They are semidominant, neomorphic, nonpleiotropic, and are associated with the insertion of a retrotransposon, tom. The Om(1A) gene, which is cytogenetically linked to the cut locus, was cloned using a DNA fragment of the cut locus of Drosophila melanogaster as a probe. Three of the eight alleles of Om(1A) examined have insertion of the tom element within a putative cut region. The gamma-ray-induced revertants of Om(1A) are accompanied with cut lethal mutations and rearrangements within the cut coding region. In the eye imaginal discs of the Om(1A) mutants, differentiation of photoreceptor clusters is suppressed, abnormal cell death occurs in the center and the cut protein is expressed ectopically. D. melanogaster flies transformed with a chimeric cut gene under the control of a heat-inducible promoter show excessive cell death in the region anterior to the morphogenetic furrow, suppressed differentiation to photoreceptor clusters and defect in the imaginal eye morphology when subjected to temperature elevation. These findings suggest that the tom element inserted within the Om(1A) region induces ectopic cut expression in the eye imaginal discs, thus resulting in the Om(1A) mutant phenotype.

Summary Isolated wheat aleurone layers acidify the incubation medium from pH 6 to 4, and this acidification is not dependent on GA3 (Hamabata et al., 1988). As an attempt to assesss the physiological role of this acidification, we have examined the effect of pH on the induction of a-amylase by GA3 in isolated wheat aleurone layers (Triticum aestivum L. cv. Tonichi). Both α-amylase production and protein synthesis induced by GA3 showed a strong pH dependence. α-Amylase activity accumulated only at pH below 5. The rate of protein synthesis decreased with the addition of GA3 at pH 6 and 5, compared to that with no GA3 added, while at pH 4 protein synthesis induced by GA3 increased almost twice. At pH 5 and 6 the SDS-PAGE fluorography of aleurone total proteins did not change significatively by GA3 addition. However, at pH 4, GA3 caused the appearance of a predominant band with the same relative molecular weight as that of purified α-amylase. The above results strongly suggest that GA3 has no action unless the aleurone layer acidifies its surrondings. In this sense, the acidification caused by aleurone layers has a permissive control on the physiological actions of GA3.

We tried to apply the use of thermosplint to prevent or protect leprosy patient's wound from risky factors in their living environment. Among 40 patients of the use of thermosplint, 27 cases wore it on some places in their hands, and 17 cases did in feet. We observed that 31 cases of the wear of thermosplint had effect on prevention or improvement in their wound, but 3 cases did not. Particularly good effect was obtained in 23 cases of the wear in their hand and 8 cases in foot. In 10 cases, however, we had to stop wearing it because of another damage or patient's uneasy. We found it difficult to apply the use of thermosplint to the plantar ulcer. Some factors such as histological and anatomical ones should be considered in more detail. Several problems of hindrances or inconveniences for daily life in wearing the thermosplint should be solved by further studies including devices for better application of the technique to the leprosy patients. At any rate it should be stressed that both patients and nurses had taken interest in the cause of the injury and could had positively come to grips with prevent of it through this study.

A sensitive rRNA-targeted reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method was developed for detection of Vibrio cholerae/mimicus, V. parahaemolyticus/alginolyticus and Campylobacter jejuni/coli by using specific primers. Counts of the enteric pathogens spiked in human stools were quantified at the lower detection limit of 10(3) cells/g stool by RT-qPCR, in marked contrast with conventional quantitative polymerase chain reaction (qPCR) at the detection limit of 10(5) to 10(6) cells/g stool. The bacterial counts determined by RT-qPCR were almost equivalent to those determined by the culture method and fluorescence in situ hybridization (FISH) during the course of in vitro culture. Bacterial rRNA in the stools was stable for at least 4 weeks when the stools were kept as the suspensions in RNA-stabilizing agent, RNAlater®, even at 37(o) C. These data suggested that the rapid and high sensitive rRNA-targeted RT-qPCR was applicable for the accurate quantification of viable enteric pathogens, such as V. cholerae/mimicus, V. parahaemolyticus/alginolyticus and C. jejuni/coli.

A non-invasive live transconjugant Shigella hybrid (LTSHΔstx) strain was constructed from a Shiga toxin gene deleted mutant of Shigella dysenteriae 1 by introducing a plasmid vector pPR1347 that carried a lipopolysaccharide biosynthesis gene (rfb and rfc) of Salmonella typhimurium. In guinea pigs, four successive oral administrations of LTSH Δstx showed complete protection against rectal challenge with wild type S. dysenteriae 1 strain. Exponential increase of the serum IgG and IgA titer against lipopolysaccharide of LTSH Δstx was observed during immunization, peaked on day 28 and remained at that level until day 35 after the initiation of the immunization. In intestinal lavage of the immunized animals, significant increase of IgA titer against lipopolysaccharide of LTSH Δstx was also observed. These data suggested that LTSH Δstx could be a useful candidate to induce protective immunity against S. dysenteriae 1 infection.

The recovery process of a Sasa tsuboiana population after a mass flowering and death in 1977 was investigated by 15 years of observation in the Hira Mountains, Kinki district, western Japan. Seed production was high (6600–13 800 seeds m−2 in Sasa plots and 3900 seeds m−2 in a forest plot) but emergent seedling density was low (14–21 seedlings m−2), probably because of seed predation by Microtus montebelli occurring between seed shedding and the next spring. The seedling density had decreased further by the next year and the S. tsuboiana population recovered from only a limited number of seedlings. In spite of such a low initial density, the S. tsuboiana population was able to regenerate successfully and attained the previous full stand height in 7–16 years. Miscantbus sinensis invaded and delayed the recovery of S. tsuboiana in one plot, but S. tsuboiana became dominant as it caught up with the height of M. sinensis. Seedling growth patterns, such as frequent tillering, the onset of rhizome extension in the early stage of seedling growth and frequent culm production from rhizomes, played important roles in the successful regeneration of S. tsuboiana.

The propagation of nonlinear hydromagnetic waves in a highly conducting, self‐gravitating fluid in a cylindrical geometry, subject to the convective forces produced by a radial temperature gradient, is treated in a Boussinesq approximation. Exact wave solutions of the nonlinear magnetohydrodynamic equations (in the Boussinesq approximation) in the presence of convective forces are obtained for the case when the physical quantities are helically symmetric in cylindrical coordinates. The solutions represent waves propagating helically on the cylindrical surfaces, under the influence of the helical magnetic and velocity fields and the convective forces. The solutions may be applicable to the hydromagnetic waves in the Earth’s fluid core and the solar convection zone with suitable modifications to account for spherical geometry.

A class of parametric instabilities of finite-amplitude, circularly polarized Alfvén waves in a plasma with pressure anisotropy is studied by application of the CGL equations. A linear perturbation analysis is used to find the dispersion relation governing the instabilities, which is a fifth-order polynomial and is solved numerically. A large-amplitude, circularly polarized wave is unstable with respect to decay into three waves: one sound-like wave and two side-band Alfvén-like waves. It is found that, in addition to the decay instability, two new instabilities that are absent in the framework of the MHD equations can occur, depending on the plasma parameters.

Vibrio cholerae O1 El Tor variant strains produced much more cholera toxin than did prototype El Tor strains. The amount of cholera toxin produced by El Tor variant strains both in vitro and in vivo was more or less equivalent to that produced by classical strains.

Pig edema disease is a bacterial disease caused by enterohemorrhagic Escherichia coli. E. coli produces Shiga toxin 2e (Stx2e), which is composed of one A subunit (Stx2eA) and five B subunits (Stx2eB). We previously reported production of Stx2eB in lettuce plants as a potential edible vaccine (Matsui et al. in Biosci Biotechnol Biochem 73:1628–1634, 2009). However, the accumulation level was very low, and it was necessary to improve expression of Stx2eB for potential use of this plant-based vaccine. Therefore, in this study, we optimized the Stx2eB expression cassette and found that a double repeated Stx2eB (2× Stx2eB) accumulates to higher levels than a single Stx2eB in cultured tobacco cells. Furthermore, a linker peptide between the two Stx2eB moieties played an important role in maximizing the effects of the double repeat. Finally, we generated transgenic lettuce plants expressing 2× Stx2eB with a suitable linker peptide that accumulate as much as 80 mg per 100 g fresh weight, a level that will allow us to use these transgenic lettuce plants practically to generate vaccine material.

Colonization factor antigens (CFAs) are important virulence factors in enterotoxigenicEscherichia coli(ETEC). Using a multiplex PCR and RT-PCR, this study tested the presence of common colonization factor-encoding genes and their expression in 50 ETEC strains isolated from stool specimens. The samples were from patients (children) with acute diarrhoea (cases) admitted to the Infectious Disease Hospital (Kolkata, India) and from normal children (controls) under 5 years of age from the community. The results indicated that coli surface antigen 6 (CS6) was the most prevalent CFA (78 %) expressed by these ETEC strains. Sequence analysis of both of the CS6 structural genes, i.e.cssAandcssB, in different ETEC isolates revealed the presence of point mutations in a systematic fashion. Based on the analysis of these variations, it was found that CssA had three alleles and CssB had two. Based on the allelic variations, subtyping of CS6 into AIBI, AIIBII, AIIIBI, AIBII and AIIIBII is proposed. The point mutations in the different alleles were reflected in a partial alteration in the secondary structure of both subunits, as determined by computational analysis. The functional significance of these changes was confirmed with cellular binding studies in Caco-2 cells with representative ETEC isolates. CS6 with AI or AIII allelic subtypes showed a higher binding capacity than AII, whereas BI showed stronger binding than BII. The AII and BII alleles were mostly detected in controls rather than in cases. The antibody specificity of BI and BII also varied due to alteration of the amino acids. Thus, CS6 variants are formed as a result of different allelic combinations of CssA and CssB, and these changes at the functional level might be important in the development of an effective ETEC vaccine.

We propose a simple structure for manipulating resonant conditions in random structures, in which a "defect" region where no scatterer is set is deliberately made in the structure. By employing a two-dimensional finite-difference time-domain method including rate equations, we examine the resonant and lasing properties observed at the defect region by changing the filling factor of scatterers. From the numerical results, we confirm that an distinct localized spot at the defect can be realized by determining an optimal filling factor and scatterer size and selecting the appropriate defect size.

Using first-order smoothing theory, Fourier analysis and perturbation methods, we obtain the evolution equation of the wave spectrum as well as the nonlinear forces generated by Alfvénic turbulence in a finite-β plasma with dispersion and phenomenological Landau-damping effects. The stability of Alfvénic turbulence is then analysed by solving the derived mean-field equations. It is shown that parallel-propagating turbulent Alfvén waves with dispersion can be modulationally unstable, leading to amplification of large-scale Alfvén waves and acoustic waves when Landau-damping effects are strong and weak respectively.

The propagation of nonlinear hydromagnetic waves in a highly conducting, self-gravitating fluid in a cylindrical geometry, subject to the convective forces produced by a radial temperature gradient, is treated in a Boussinesq approximation. It is shown that there is a class of exact wave solutions with large amplitude but restricted form.

Exact wave solutions of the nonlinear magnetohydrodynamic equations for a highly conducting incompressible fluid within an axisymmetric container are obtained for the case when the physical quantities are independent of the axial coordinate or the azimuthal angle in the cylindrical coordinates. The solutions represent waves propagating in the azimuthal or axial direction under the influence of helical magnetic and velocity fields whose strength varies with radius. The solutions are applicable to astrophysical and laboratory plasmas as well as the Earth’s core.

Exact wave solutions of the nonlinear magnetohydrodynamic equations for a highly conducting incompressible fluid within an axisymmetric container are obtained for the case when the physical quantities are helically symmetric in cylindrical coordinates. The solutions represent the waves propagating helically on the cylindrical surfaces, under the influence of helical magnetic and velocity fields whose strength varies with radius. The solutions are applicable to astrophysical and laboratory plasmas as well as the Earth’s core.

The modulational instability of Alfven wave turbulence in a plasma with dispersive effects is considered. The influence of Alfven wave turbulence on low frequency (long wavelength) acoustic waves is adequately described by using the techniques of Fourier analysis. It is shown that the presence of Alfven wave turbulence can amplify acoustic waves.

Using first-order smoothing theory, Fourier analysis and perturbation methods, we obtain the evolution equation of the wave spectrum as well as the nonlinear forces generated by random Alfvén waves in a finite-β plasma with phenomenological Landau-damping effects. The effect of microscale random Alfvén waves on the propagation of large-scale hydromagnetic waves is also investigated by solving the mean-field equations. It is shown that parallel-propagating random Alfvén waves are modulationally stable and that obliquely propagating random Alfvén waves can be modulationally unstable when the energy of random waves is converted to slow magneto-acoustic waves that can be Landau-damped, providing a dissipation mechanism for the Alfvén waves.

Vasotocin (VT) has been shown to influence various aspects of social and sexual behaviors in a broad range of vertebrate species, but less is known about the mechanisms through which this peptide modulates behavior. Additionally, much less is known about roles of isotocin (IT) in regulation of behavior. Grass puffer, Takifugu niphobles, has unique spawning behavior; spawning occurs on beach only for several days around the spring tide and is conducted by a group of 10-60 individuals, of which one is female. As a first step toward investigating the roles of VT and IT in this species' spawning behavior, we determined the structures of the VT and IT genes from grass puffer using the genome resources of the closely related tiger puffer and green puffer. We then used these sequences to develop real-time PCR assays and examined changes in expression of the VT and IT genes over the spawning season. The structures of VT and IT genes are well conserved among three puffer species. Particularly, the sequence similarities between grass and tiger puffers were very high not only in the coding region (85-99%), but also in the non-coding regions (92-98%) that include the 5'-upstream regions. The levels of expression of VT gene increased in the brain of pre-spawning females. The levels of VT mRNA in the spawning females tended to be higher than that in the spawning males. In contrast, the levels of IT mRNA did not show such variation. The present results suggest that VT gene expression augments in the brain of females during the spawning period. The unique spawning behavior of grass puffer provides a useful model for studying the molecular mechanism of sexual behavior utilizing the genome resources of tiger puffer.

Shiga toxins produced by enterohemorrhagic Escherichia coli (EHEC) include Shiga toxin 1 (Stx1) as well as Shiga toxin 2 (Stx2). Stx1 is cell associated, whereas Stx2 is localized to the culture supernatant. We have analyzed the secretion of Stx2 by generating histidine-tagged StxB (StxB-H). Although neither StxB1-H nor StxB2-H was secreted in StxB-H-overexpressed EHEC, StxB2-H-overexpressed EHEC showed inhibited Stx2 secretion. On the other hand, StxB1-H-overexpressed EHEC showed no alteration of Stx2 secretion. B-subunit chimeras of Stx1 and Stx2 were used to identify the specific residue of StxB2 that the Stx2 secretory system recognizes. Alteration of the serine 31 residue to an asparagine residue (S31N) in StxB2-H enabled the recovery of Stx2 secretion. On the other hand, alteration of the asparagine 32 residue to a serine residue (N32S) in StxB1-H caused the partial secretion of a point-mutated histidine-tagged B subunit in EHEC. Based on the evidence, it appeared possible that this residue might contain secretion-related information for Stx2 secretion. To investigate this hypothesis, we constructed an isogenic mutant EHEC (Stx1B subunit, N32S) strain and an isogenic mutant EHEC (Stx2B subunit, S31N) strain. Although the mutant Stx2 was cell associated in isogenic mutant EHEC, mutant Stx1 was not extracellular. However, when we used plasmids for the expression of the mutant holotoxins, the overexpressed mutant Stx1 was found in the supernatant fraction, and the overexpressed mutant Stx2 was found in the cell-associated fraction in mutant holotoxin gene-transformed EHEC. These results indicate that the serine 31 residue of the B subunit of Stx2 contains secretion-related information.

We have carried out nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on ThRu2Si2 and LaRu2Si2, which are the nonmagnetic references of the intriguing heavy fermion URu2Si2. The comparisons of URu2Si2 with the reference materials allow us to analyze the already known NMR and NQR data on URu2Si2 phenomenologically and semiquantitatively. The study of 101Ru-NQR frequency suggests the relatively close electronic configuration of URu2Si2, including the valence of the actinide ion, to that of the tetravalent ThRu2Si2 at high temperatures, as well as the delocalization of 5f electrons at low temperatures. Ising-like spin fluctuations along the c-axis were brought to light by 29Si-NMR data in the so-called hidden order phase of URu2Si2. The unique magnetic property is plausibly associated with the mechanism of the unconventional superconductivity.

The Matlab variants of Vibrio cholerae O1, defined as hybrids between the classical and El Tor biotypes, were first isolated from hospitalized patients with acute secretory diarrhoea in Matlab, a rural area of Bangladesh. These variants could not be categorized as classical or El Tor biotypes by phenotypic and genotypic tests, and had representative traits of both the biotypes. A number of virulence-associated genes and/or gene clusters were screened by PCR and DNA sequencing. El Tor-specific gene clusters, Vibrio seventh-pandemic islands (VSP)-I and -II and repeat toxin (RTX) were present in the genome of these variants, indicating their El Tor lineage, whereas the nucleotide-sequence-derived CtxB amino acid sequence of these strains grouped them under the classical biotype. Matlab variants possessed all the necessary genes to initiate pandemics. The genetic relatedness of Matlab variants to the V. cholerae strains recently isolated in Mozambique is another important observation of this study, which underscores the epidemiological significance of Matlab variants.