Characterization of recombinant prolyl aminopeptidase from Aspergillus oryzae

AIMS

Prolyl aminopeptidase (PAP) degrades only amino-terminal proline from peptides. The food-grade fungus Aspergillus oryzae produces this enzyme only in small amounts. In this paper, we present efficient production of recombinant PAP with an overexpression system of A. oryzae and characterization of its biochemical properties.

METHODS AND RESULTS

The gene encoding PAP was overexpressed as a His-tag fusion protein under a taka-amylase gene (amyB) promoter with a limited expressing condition in A. oryzae. The PAP activity in the mycelia grown in rich medium containing glucose (repressing condition) was twice that in starch (inducing condition). The enzyme prepared as cell-free extract was partially purified through two-step column chromatography. The PAP was estimated to be a hexameric protein and exhibited salt tolerance against NaCl of up to 4 mol l(-1).

CONCLUSIONS

Aspergillus oryzae PAP was produced under the repressing condition of amyB promoter in a PAP-overexpressing strain and purified 1800-folds. Overproduction of PAP under promoter-inducing conditions led to an increase in inactive PAP, possibly because of irregular folding.

SIGNIFICANCE AND IMPACT OF THE STUDY

PAP with a high specific activity and salt tolerance may be used effectively in the manufacturing processes of fermented foods.

Transition between internal transport barriers with different temperature-profile curvatures in JT-60U Tokamak plasmas

A spontaneous transition phenomena between two states of a plasma with an internal transport barrier (ITB) is observed in the steady-state phase of the magnetic shear in the negative magnetic shear plasma in the JT-60U tokamak. These two ITB states are characterized by different profiles of the second radial derivative of the ion temperature inside the ITB region (one has a weak concave shape and the other has a strong convex shape) and by different degrees of sharpness of the interfaces between the L mode and the ITB region, which is determined by the turbulence penetration into the ITB region.

Measurement of derivative of ion temperature using high spatial resolution charge exchange spectroscopy with space modulation optics

A new technique to measure the first and second derivatives of the ion temperature profile has been developed by using a charge exchange spectroscopy system with space modulation optics. The space observed is scanned up to +/-3 cm with a cosine wave modulation frequency up to 30 Hz by shifting the object lens in front of the optical fiber bundle by 0.5 mm with a piezoelement. The first and second derivatives of ion temperature are derived from the modulation component of the ion temperature measured by using Fourier series expansion.

Nodular-type muscle sarcoidosis developing after a dog bite

We report a 46-year-old woman who experienced swelling of the right thigh around the wound caused by a dog bite. Physical findings, laboratory findings, imaging studies, and muscle biopsy showed that this was nodular-type muscle sarcoidosis. This is an unusual case of sarcoidosis, and the possibility is discussed that a dog bite may serve as a trauma to trigger sarcoidosis in genetically predisposed individuals.

Identification of a low plasma-rotation threshold for stabilization of the resistive-wall mode

The plasma rotation necessary for stabilization of resistive-wall modes (RWMs) is investigated by controlling the toroidal plasma rotation with external momentum input by injection of tangential neutral beams. The observed threshold is 0.3% of the Alfvén velocity and much smaller than the previous experimental results obtained with magnetic braking. This low critical rotation has a very weak beta dependence as the ideal wall limit is approached. These results indicate that for large plasmas such as in future fusion reactors with low rotation, the requirement of the additional feedback control system for stabilizing RWM is much reduced.

Who can get the beneficial effect from lateral lymph node dissection for Dukes C rectal carcinoma below the peritoneal reflection?

PURPOSE

This study was designed to identify those patients with Dukes C rectal carcinoma below the peritoneal reflection who might benefit from lateral lymph node dissection.

METHODS

The study involved 104 consecutive Dukes C patients who received total mesorectal excision with lateral lymph node dissection for rectal carcinoma below the peritoneal reflection between 1990 and 2002. The patients were retrospectively divided into three groups: patients without lateral spread (Group I: n = 52), patients with nodal involvement between the inferior hypogastric nerve and the internal iliac artery (Group II: n = 16), and patients with nodal involvement in the obturator space (Group III: n = 36). The patients also were divided into two groups according to the number of lateral nodes involved: less than four (n = 42) and at least four (lateral nodes involved: n = 10). Nodal involvement was determined histologically.

RESULTS

The local recurrence and overall five-year survival rates were 5.8 and 66.9 percent in Group I, 18.8 and 59.8 percent in Group II, and 33.3 and 23.6 percent in Group III, respectively. These outcomes did not differ significantly between Groups I and II, but they were significantly worse in Group III than in Groups I and II, with the survival being significantly better in the patients with less than four histologically positive lateral nodes involved (43.2 percent) than in those with at least four positive lateral nodes involved (0 percent).

CONCLUSIONS

Lateral lymph node dissection was effective for Dukes C rectal carcinoma below the peritoneal reflection with positive lateral nodes involved in the space between the autonomic nerve and the internal iliac artery and in patients with less than four positive lateral nodes.

Interacting molecule of AT1 receptor, ATRAP, is colocalized with AT1 receptor in the mouse renal tubules

The renin-angiotensin system in the kidney plays a critical role in the regulation of renal hemodynamics and sodium handling through the activation of vascular, glomerular and tubular angiotensin II type 1 (AT1) receptor-mediated signaling. We previously cloned a molecule that specifically bound to the AT1 receptor and modulated AT1 receptor signaling in vitro, which we named ATRAP (for AT1 receptor-associated protein). The purpose of this study is to analyze the renal distribution of ATRAP and to examine whether ATRAP is co-expressed with the AT1 receptor in the mouse kidney. We performed in situ hybridization, Western blot analysis, and immunohistochemistry to investigate the expression of ATRAP mRNA and protein in the mouse kidney. The results of Western blot analysis revealed the ATRAP protein to be abundantly expressed in the kidney. Employing in situ hybridization and immunohistochemistry, we found that both ATRAP mRNA and the protein were widely distributed along the renal tubules from Bowman's capsules to the inner medullary collecting ducts. ATRAP mRNA was also detected in the glomeruli, vasculature, and interstitial cells. In all tubular cells, the ATRAP protein colocalized with the AT1 receptor. Finally, we found that the dietary salt depletion significantly decreased the renal expression of ATRAP as well as AT1 receptor. These findings show ATRAP to be abundantly and broadly distributed in nephron segments where the AT1 receptor is expressed. Furthermore, this is the first report demonstrating a substantial colocalization of ATRAP and AT1 receptor in vivo.

Measurement of turbulence decorrelation during transport barrier evolution in a high-temperature fusion plasma

A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast with the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation.

Characterization of pNI10 plasmid in Pseudomonas, and the construction of an improved Escherichia and Pseudomonas shuttle vector, pNUK73

The complete nucleotide sequence of pNI10 (3.75 kb), from which pNI105 and pNI107 were constructed as medium-host-range vectors for Gram-negative bacteria, was determined. A fragment of about 2.1 kb of pNI10 was essential for replication in Escherichia coli and Pseudomonas fluorescens. This fragment encodes a putative origin of replication ( ori) and one putative replication-controlling protein (Rep). An improved version of the medium-host-range plasmid vector pNUK73 (5.13 kb) was constructed with the basic-replicon of pNI10 and pHSG298 (2.68 kb). We show that expression in pseudomonads of the bromoperoxidase gene ( bpo) of Pseudomonas putida, inserted downstream of the lac promoter in pNUK73, resulted in about 30% (13.6 U/l culture) of the enzyme level obtained in E. coli.

Minimally invasive transanal surgery for localized rectal carcinoid tumors

Local excision is often fully justified for rectal carcinoid tumors. However insufficient surgical field and difficult access to proximal tumors have been drawbacks in performing pre-existing local excision procedures. A novel local excisional technique called minimally invasive transanal surgery (MITAS) has been experimented for local removal of carcinoid tumors in the rectum. A specially designed anal retractor connected to the Octopus retractor holder was used and an ENDO-stapler allowed the simultaneous excision and anastomosis to be performed. Eight patients with carcinoid tumors in the rectum (4 tumors in the upper rectum) underwent MITAS. Median distance from anal verge to proximal tumor was 6.5 cm (range, 5-12 cm). The median diameter of the tumor was 9 mm. Median operative time was 18.5 minutes and blood loss was minimal. No analgesics were needed postoperatively, and there was no morbidity or mortality. Full-thickness excision of the rectum was accomplished and the tumors confined in the submucosa were demonstrated histologically to be with free surgical margins. No recurrences have been observed with a median follow-up period of 39 months. The technique facilitates total excisional biopsy for rectal carcinoid tumors and reduces operative time, blood loss and complications.

Plasma equilibrium and confinement in a tokamak with nearly zero central current density in JT-60U

A high confinement equilibrium with nearly zero toroidal current in the central region (a "current hole") has been observed for the first time to persist stably for several seconds in the JT-60U tokamak. This observation indicates the possibility of stable tokamak operation without central toroidal current; the central current has previously been believed to be necessary in tokamaks. The radius of the current hole extended up to 40% of the plasma minor radius. It was observed that the current hole was formed by the increase of the off-axis noninductive current.

Immunization with plasmid DNA encoding MHC class II binding peptide/CLIP-replaced invariant chain (Ii) induces specific helper T cells in vivo: the assessment of Ii p31 and p41 isoforms as vehicles for immunization

A single helper T cell (Th) epitope-specific T cell subset was successfully induced in vivo by immunization with plasmid DNA encoding MHC class II binding peptide/class II-associated invariant chain peptide (CLIP)-replaced murine Ii molecules. Spleen cells from mice immunized by gene gun bombardment with plasmid DNA for Ii p31 and p41 molecules, whose CLIP regions were replaced with an I-A(d)-restricted Th epitope, ovalbumin (OVA) 323-336, showed the specific proliferation and interferon-gamma (IFN-gamma) production. A20-2J B cell lines having these plasmids were capable of stimulating spleen cells from the immunized mice and naïve DO10-transgenic mice bearing the epitope-specific T cell receptor (TCR) transgenes by examining the specific proliferative response and IFN-gamma production. Some mice immunized with the Ii p41-OVA323, but not with the Ii p31-OVA323 plasmid, produced the peptide-specific antibodies, suggesting the functional difference between Ii isoforms.

Structural requirements of sphingosine molecules for inhibition of DNA primase: biochemical and computational analyses

Using 28 chemically well-defined compounds containing D-erythro-sphingosine and its analogues, we analyzed structure-activity relationships for DNA primase inhibition. Biochemical studies demonstrated a positively charged amino group at C2 and a long aliphatic chain to be absolutely required for inhibition. Whereas C2-amino group is intact, sphingosine 1-phosphate was totally inactive. This result could be due to cancellation of positive charge of the amino group by the interaction with negatively charged C1-phosphate, since simulations with the software INSIGHT II showed these two groups to be close enough to interact. The hydroxyl group at C3 and trans-double bond at C4-C5 were also found to be important for the inhibition. Dehydroxylation of C3, as well as saturation or cis-conversion of the trans-double bond led to decrease of inhibitory activity. Despite saturation of the double bond, introduction of a hydroxyl group into C4 of dihydrosphingosine resulted in restoration of inhibition. Conversion of the double bond into a triple bond did not abolish but rather enhanced the inhibitory activity. Among sphingosine stereoisomers, the naturally occurring D-erythro-sphingosine proved to be the strongest inhibitor. To ascertain the contribution of the total conformation to the inhibition, especially of the long aliphatic chain, we constructed a 3D-quantitative structure-activity relationship model using the computer program Catalyst/HipHop on the basis of information described above. Analysis of the hypothesis model for active compounds revealed that the orientation of aliphatic chain, represented by the dihedral angle of C2-3-4-5, correlated well with the inhibition. Modifications such as deletion of the hydroxyl group at C3 or saturation of the C4-C5 double bond caused shifts in the dihedral angle of C2-3-4-5, with concomitant decrease in inhibitory activity.

Identification of immunostimulatory DNA-induced genes by suppression subtractive hybridization

Bacterial DNA and related synthetic immunostimulatory oligodeoxyribo-nucleotides (ISS-ODN) have stimulatory effects on mammalian immune cells through a Toll-like receptor, TLR9. Genes upregulated in ISS-ODN-stimulated immune cells are obviously significant to delineate the mechanism of the induced innate immunity. Employing suppression subtractive hybridization (SSH), we have generated a profile of genes induced by ISS-ODN in spleen cells. Sequencing of 87 clones isolated by the SSH showed 39 clones corresponding to known mouse genes in the public database. Eleven clones appeared to possess 80-90% homology with known mouse genes and the remaining 37 clones showed no significant homology with any known mouse genes. A series of known genes which have not previously been reported to be induced with ISS-ODN were confirmed to be induced in ISS-ODN-stimulated bone marrow-derived macrophages: NF-kappaB p105, IRF-1, PA28beta, IRG2, and MyD88. These genes were suggested to be involved in the molecular process of innate host defense mechanisms.

Quasisteady high-confinement reversed shear plasma with large bootstrap current fraction under full noninductive current drive condition in JT-60U

A quasisteady reversed shear plasma with a large bootstrap current fraction ( approximately 80%) has been obtained for the first time in the JT-60U tokamak. The shrinkage of reversed shear region was suppressed by the bootstrap current peaked at the internal transport barrier (ITB) layer and the ITBs at a large radius were sustained, which, by combination with an H-mode edge pedestal, resulted in a high confinement or 2.2 times the H-mode scaling for 6 times energy confinement time or 2.7 s. Furthermore, a full noninductive current drive was obtained by the bootstrap current and the beam driven current.

Protective CTL response is induced in the absence of CD4+ T cells and IFN-gamma by gene gun DNA vaccination with a minigene encoding a CTL epitope of Listeria monocytogenes

Our work was undertaken to learn the mechanism of induction of protective cytotoxic T lymphocytes (CTL) by gene gun DNA vaccination with p91m encoding an H-2Kd-restricted T cell epitope of listeriolysin O (LLO). Vaccination with p91m induced vigorous antigen-specific CD8+ CTL that produce IFN-gamma and was able to confer partial protection against listerial challenge. However, the p91m-induced protective immunity was revealed to be independent of the IFN-gamma and CD4+ T cell help. The CTL induction is also suggested to require neither adjuvant activity of the plasmid used nor IFN-gamma. The data may be feasible for the design of CTL inducing vaccines in various immunodeficiencies.

Electroporation-mediated transfer of cytokine genes into human esophageal tumors produces anti-tumor effects in mice

Electroporation facilitates transfer of chemicals or plasmid DNA from extracellular milieu into cells by increasing the permeability of the cell membrane. Delivery of electric pulses to established tumors thereby can improve the susceptibility of tumors to an anti-cancer agent administered. We examined whether electroporation-mediated transfer of cytokine genes into solid tumors could produce anti-tumor effects in the tumor-bearing mice. Plasmid DNA containing cytokine genes were injected into human esophageal T.Tn tumors developed in nude mice and electric pulses were then delivered. Administration of murine GM-CSF or human IL-2 gene followed by electroporation significantly suppressed the subsequent growth of T.Tn tumors and prolonged the survival of the inoculated mice. In contrast, electroporation-mediated introduction of a control gene, human GM-CSF gene, whose products do not bind to murine GM-CSF receptors, did not achieve any anti-tumor effects. In vivo transfection of cytokine genes with electroporation could be a possible therapeutic strategy for established solid tumors.

Protective cytotoxic T lymphocyte responses induced by DNA immunization against immunodominant and subdominant epitopes of Listeria monocytogenes are noncompetitive

Taking advantage of the fact that plasmid DNA encoding a single cytotoxic T lymphocyte (CTL) epitope can induce CTLs, we examined the influence of T-cell responses to dominant epitopes on those to a subdominant epitope derived from Listeria monocytogenes. Our data suggest that interaction between T cells against dominant and subdominant epitopes does not operate in the generation of the hierarchy. Furthermore, we found that a single dominant epitope is sufficient for the induction of protective immunity.

Combinatory anti-tumor effects of electroporation-mediated chemotherapy and wild-type p53 gene transfer to human esophageal cancer cells

Delivery of electric pulses to an established solid tumor augments the permeability of cell membrane and increases the susceptibility of tumors to an anti-cancer agent that is administered in the vicinity of tumors. Forced expression of the wild-type p53 gene in tumor cells that have non-functional p53 gene(s) can also enhance their sensitivity to a DNA-damaging agent. To investigate the feasibility of electroporation-mediated therapy for cancer, electric pulses were delivered to human esophageal tumors developed in nude mice after they received an anti-cancer agent and/or plasmid DNA containing the wild-type p53 gene. The growth of esophageal tumors was suppressed with electroporation-mediated chemotherapy compared with the treatment with an anti-cancer agent or electroporation alone. Intratumoral injection of the wild-type p53 gene into p53-mutated esophageal tumors followed by electroporation also inhibited tumor growth. When mice were administered with the wild-type p53 gene and an anti-cancer agent, subsequent electroporation produced a synergistic therapeutic effect. Combinatory transfer of plasmid DNA and a pharmacological agent by electroporation is thereby a possible therapeutic strategy for the treatment of solid tumors.

Myocardial damage and left ventricular dysfunction in patients with and without persistent negative T waves after Q-wave anterior myocardial infarction

Persistent T-wave inversions during the chronic stage of Q-wave myocardial infarction (MI) indicate the presence of a transmural infarction with a fibrotic layer pathologically. The aim of the present study was to examine the relation between left ventricular (LV) damage and changes in polarity of the T waves from the acute to chronic phase in patients with Q-wave anterior wall MI. We studied 140 patients with persistent T-wave inversions in leads with Q waves (negative T-wave group) and 158 patients with positive T waves (positive T-wave group) at 12 months after anterior MI. In the positive T-wave group, the precordial T waves reverted from a negative to a positive morphology < 3 months after MI in 21 patients (3 M-positive T-wave subgroup), 3 to 6 months in 52 patients (6 M-positive T-wave subgroup), and 6 to 12 months in 75 patients (12 M-positive T-wave subgroup). Ten patients had persistent positive T waves without initial T-wave inversion (persistent positive T-wave group). Wall motion index and LV dimension were higher and the wall thickness for the infarct area and LV ejection fraction were lower in the negative T-wave than in the positive T-wave groups, except the persistent positive T-wave group in the chronic stage (p < 0.0001). Wall motion in the infarcted area improved over the course of 1 year in the 3 M-, 6 M-, and 12 M-positive T-wave subgroups (p < 0.0001), but not in the persistent positive T-wave group. Among the patients with T-wave inversions after admission, those who had persistent negative T waves after 12 months had worse LV function. In patients with initial T-wave inversion, earlier normalization of the precordial T waves was associated with greater improvement in LV function. Patients with persistent positive T waves without initial negative T waves had poorer recovery of LV function than patients with persistent negative T waves. We conclude that the presence of inverted T waves in leads with abnormal Q waves 12 months after MI and the time required for T-wave normalization can be used to assess the degree of LV dysfunction.