Search

Although plant phosphate uptake is reduced by low soil temperature, arbuscular mycorrhizal (AM) fungi are responsible for P uptake in many plants. We investigated growth and carbon allocation of the AM fungus Glomus mosseae and a host plant (Plantago lanceolata) under reduced soil temperature. Plants were grown in compartmented microcosm units to determine the impact on both fungus and roots of a constant 2.7 °C reduction in soil temperature for 16 d. C allocation was measured using two (13)CO(2) pulse labels. Although root growth was reduced by cooling, AM colonization, growth and respiration of the extraradical mycelium (ERM) and allocation of assimilated (13)C to the ERM were all unaffected; the frequency of arbuscules increased. In contrast, root respiration and (13)C content and plant P and Zn content were all reduced by cooling. Cooling had less effect on N and K, and none on Ca and Mg content. The AM fungus G. mosseae was more able to sustain activity in cooled soil than were the roots of P. lanceolata, and so enhanced plant P content under a realistic degree of soil cooling that reduced plant growth. AM fungi may therefore be an effective means to promote plant nutrition under low soil temperatures.

In order to reduce weight of a vehicle, application of light metals has increased. Magnesium alloy is very light and has high specific strength compared to other structural metals. SPR (Self Piercing Rivet) joining has been applied mainly for an aluminum alloy in motor industries. However, application of SPR joining to a magnesium alloy is very limited. In this study, SPR joining was carried out with AM50 magnesium alloy sheets. According to the result of joining experiment, cracking easily occurred at the lower sheet due to poor formability of the alloy. Static and fatigue strength of the joint were evaluated under shear tensile loading condition. The crack introduced in SPR process affects on strength of the joint. As a practical way to solve the problem, adhesive aided SPR joining was proposed. Adhesive was spread on the surface and then SPR joining was conducted before its hardening. The maximum shear tensile load of the joint increased by using an adhesive and was strongly influenced by kind of adhesive used. Fatigue strength also improved by using an adhesive. It is proposed that control for deformation due to SPR process at the edge of the joining area could be effective to improve the strength.

Colonization of plant roots by arbuscular mycorrhizal (AM) fungi is a primary factor determining mycorrhizal associations. This study aimed to investigate the variation in AM colonization among maize genotypes and in response to plant breeding programs. Three types of maize (Zea mays) germplasms composed of 141 inbred lines, 38 hybrids, and 76 landraces were grown in replicated field experiments in Sapporo, Japan, for two cropping years to evaluate the percentage of root length colonized by indigenous AM fungi. The percent colonization varied greatly and continuously among maize genotypes. Inbred lines that originated (released) in particular locations (e.g., Tokachi, Japan) and years (e.g., 1960s) showed significantly larger values than other lines. Inter-location differences were also observed for landraces. The direction of the year-of-release effect on colonization depended on the origin. No significant differences were observed between leaf-blight-disease-resistant near-isogenic inbred lines and their parents. Modern hybrids showed significantly greater values than inbred lines and older landraces. Evaluating numerous, diverse genotypes demonstrated that AM colonization of maize plants varies with germplasm type, origin (country and location), and year of release, and that modern plant breeding programs do not necessarily lead to the suppression of colonization.

Though adult Lymnaea are bimodal breathers, young animals breathe mainly through the skin and adults through the lung. Operant conditioning changes adult breathing behavior from aerial to cutaneous. We hypothesized that this behavioral change is caused by alterations in the neuronal circuit during both development and conditioning. We focused our study on whether the synaptic connection between RPeD1 and RPA6 neurons is modulated during development and conditioning. Our findings indicated that the RPeD1 has an excitatory monosynaptic contact with the RPA6 in young naive and operantly-conditioned adult animals. The relationship of this contact was well correlated with their respiratory behavior.

This study characterized the microbial interaction of Peptostreptococcus micros and Prevotella intermedia, the major pathogens of dentoalveolar infection, using a murine model. Subcutaneous injection of P. micros cells in the dorsum of the mouse together with living cells of P. intermedia resulted in a significantly larger abscess when compared with single injection of the organisms (P < 0.02). The abscess size was also significantly increased (P < 0.05) when the plate-cultured cell suspension of P. micros was injected into mouse with the culture filtrate of P. intermedia. The heat-treated culture filtrate of P. intermedia also enhanced the virulence of P. micros. P. micros culture filtrate did not affect the virulence of P. intermedia. Interestingly, the virulence of P. micros appeared to be enhanced even when the culture filtrate of P. intermedia was injected at separate sites in the mouse. These results suggest that a heat-stable product or products of P. intermedia increase the virulence of P. micros indirectly by altering the host condition, whereas living cells of P. micros can directly enhance virulence of P. intermedia.

Recent studies on crop rotation have suggested that the cultivation of mycorrhizal host crops increases the arbuscular mycorrhizal (AM) colonization of succeeding crops. A pot experiment was conducted to determine whether the positive effect of AM host cropping on the growth of succeeding maize is mainly due to the multiplication of indigenous AM fungi. Maize plants were grown in soils after mustard (non-host) cropping without AM fungal (AMF) inoculum (MD NI ); with inoculum from the soil after sunflower cropping (MD ISF ); with sterilized inoculum (MD SI ); and in the soil after sunflower (host) cropping without inoculum (SF NI ). The growth of maize after mustard cropping (MD NI ) was inferior to that after sunflower cropping (SF NI ). The AMF inoculum from the soil after sunflower cropping (MD ISF ) improved the growth and AM colonization of maize, and shoot weight was increased from 17 to 49% of that in the SF NI treatment. However, the sterilized inoculum (MD SI ) did not show similar effects. Similar AMF species to those increased by sunflower cropping were dominant in SF NI -treated or MD ISF -treated soils following maize cropping, also indicating that the AM colonization of maize was improved by multiplied AM fungi through sunflower cropping. These results suggest that the effects of preceding crops on maize growth are at least partly due to differences in AMF density caused by various preceding crops.

Configurations of shock wave reflection in steady supersonic flows have been experimentally investigated using a combination of two wedges. It has been experimentally proved by a symmetric arrangement that both regular and Mach reflections are possible in the dual-solution domain for various aspect ratio models. In the arrangement for the purpose of clarifying the influence of the wedge three-dimensionality, the transition from regular to Mach reflection can happen at any inlet aspect ratio, both when the inlet aspect ratio is increased and when it is reduced. The inlet aspect ratio has no effect on the transition provided it is high enough for the regular reflection point at the spanwise centre to be free from information from wedge edges. Flow visualization data produced using the vapour screen technique indicate that, in a region influenced by information from wedge edges, the three-dimensionality of experimental models promotes regular reflection rather than Mach reflection. To study the criteria for the transition between regular and Mach reflections, an asymmetric arrangement of two wedges has been used, and a hysteresis effect is clearly evident. The transition from regular to Mach reflection, however, occurs significantly below the detachment condition, and moreover, the repeatability of the transition angle is not satisfactorily achieved. These experimental results imply that wind tunnel disturbances may dominate the transition in the dual-solution domain. The stability of regular reflection in the dual-solution domain is discussed, and effects of free-stream disturbances are experimentally examined by producing water vapour in the free stream as an artificial disturbance.

This paper presents a new control strategy to stably support the rotor shaft when a bearingless motor (BELM) based on d-q axis current control is driven under loaded condition. In this type BELM, the magnitude and direction of the suspension force are varied in accordance with the rotor rotation. Unfortunately, it results in the unstable rotor levitation. Thus, the necessity of the compensation for the suspension force command and the validity of that compensation method have been introduced by the authors earlier. However, it is possible that the magnitude and the direction of suspension force are varied with armature reaction under loaded condition. It causes the serious problem in the rotor levitation. Thus, it is obviously found in this paper how the compensation coefficients are conducted to realize the stable rotor levitation even under loaded condition. The effectiveness of the compensation coefficients derived by the proposed method is confirmed in simulation based on a machine model designed by Finite Element Method (FEM) software.

The growth rates R Si , of Si films deposited on Si(001)2 × 1 from Si 2 H 6 by gas-source molecular-beam epitaxy (GS-MBE) were determined as a function of temperature T s (500–950 °C) and impingement flux J Si 2 H 6 (0.3–7.7 × 10 16 cm −2 s −1 ). R Si (T s , J Si 2 H 6 ) curves were well described using a model, with no fitting parameters, based upon dissociative Si 2 H 6 chemisorption followed by a series of surface decomposition reactions with the ratelimiting step being first-order hydrogen desorption from Si monohydride. The zero-coverage Si 2 H 6 reactive sticking probability in the impingement-flux-limited growth regime was found to be 0.036. B doping concentrations (C B = 5 × 10 16 − 5 × 10 19 cm −3 ) from B 2 H 6 increased linearly with increasing flux ratio J B 2 H 6 /J Si 2 H 6 at constant T s and decreased exponentially with 1/T s at constant J B 2 H 6 /J Si 2 H 6 . The B 2 H 6 reactive sticking probability ranged from ≅ 6.4 × 10 −4 at T s = 600 °C to 1.4 × 10 −3 at 950 °C. Secondary ion mass spectrometry analyses of modulation-doped samples revealed sharp profiles with no detectable B segregation. Hole mobilities in uniformly-doped samples were equal to bulk values.

B‐doped Si(001)2×1 films were grown on Si(001) substrates by gas‐source molecular beam epitaxy using Si2H6 and B2H6. B concentrations CB (5×1016–5×1019 cm−3) were found to increase linearly with increasing flux ratio JB2H6/JSi2H6 (9.3×10−5–2.5×10−2) at constant film growth temperature Ts (600–950 °C) and to decrease exponentially with 1/Ts at constant JB2H6/JSi2H6 ratio. The B2H6 reactive sticking probability ranged from ≂6.4×10−4 at Ts=600 °C to 1.4×10−3 at 950 °C. The difference in the overall activation energies for B and Si incorporation at Ts=600–950 °C is ≂0.34 eV. A comparison of quantitative secondary‐ion mass spectrometry (SIMS) and temperature‐dependent Hall‐effect measurements showed that B was incorporated into substitutional electrically active sites over the entire B concentration range investigated. SIMS B depth profiles from modulation‐doped samples were abrupt with no indication of surface segregation to within the instrumental resolution limit and initial δ‐doping experiments were carried out. Structural analysis by in situ reflection high‐energy electron diffraction combined with post‐deposition high‐resolution plan‐view and cross‐sectional transmission electron microscopy showed that all films were high‐quality single crystals with no evidence of dislocations or other extended defects. Temperature‐dependent (20–300 K) hole carrier mobilities were equal to the best reported bulk Si:B values and in good agreement with theoretical maximum values.

The growth rates RSi of Si films deposited on Si(001)2×1 from Si2H6 by gas‐source molecular‐beam epitaxy were determined as a function of temperature Ts (500–950 °C) and impingement flux JSi2H6 (0.3–7.7×1016 cm−2 s−1). RSi (Ts,JSi2H6) curves were well described using a model, with no fitting parameters, based upon dissociative Si2H6 chemisorption followed by a series of surface decomposition reactions with the rate‐limiting step being first‐order hydrogen desorption from Si monohydride. The zero‐coverage Si2H6 reactive sticking probability in the impingement‐flux‐limited growth regime was found to be 0.036, more than two orders of magnitude higher than that for SiH4. B doping concentrations (CB=5×1016–3×1019 cm−3) from B2H6 increased linearly with increasing flux ratio JB2H6/JSi2H6 at constant Ts and decreased exponentially with 1/Ts at constant JB2H6/JSi2H6. Secondary ion mass spectrometry analyses of modulation‐doped samples revealed sharp profiles with no detectable B segregation. Hole mobilities in un...

Although plant phosphate uptake is reduced by low soil temperature, arbuscular mycorrhizal (AM) fungi are responsible for P uptake in many plants. We investigated growth and carbon allocation of the AM fungus Glomus mosseae and a host plant (Plantago lanceolata) under reduced soil temperature. Plants were grown in compartmented microcosm units to determine the impact on both fungus and roots of a constant 2.7 °C reduction in soil temperature for 16 d. C allocation was measured using two (13)CO(2) pulse labels. Although root growth was reduced by cooling, AM colonization, growth and respiration of the extraradical mycelium (ERM) and allocation of assimilated (13)C to the ERM were all unaffected; the frequency of arbuscules increased. In contrast, root respiration and (13)C content and plant P and Zn content were all reduced by cooling. Cooling had less effect on N and K, and none on Ca and Mg content. The AM fungus G. mosseae was more able to sustain activity in cooled soil than were the roots of P. lanceolata, and so enhanced plant P content under a realistic degree of soil cooling that reduced plant growth. AM fungi may therefore be an effective means to promote plant nutrition under low soil temperatures.

Instability of an electronic Floquet state in the semiconductor Wannier‐Stark ladder (WSL) driven by an intense monochromatic THz wave is investigated by virtue of the R‐matrix Floquet theory. It is revealed that a dynamic localization (DL) characteristic of this system is unstable against the Fano resonance‐like interminiband decay mechanism caused by the THz‐mediated interaction, termed here the dynamic Fano resonance (DFR). The result obtained here is sharply contrasted with the conventional understanding without the introduction of DFR that the degree of stability of the DL would be comparable to that of the WSL with no THz drive.

Reactive zinc metal can be prepared by the electrolysis of a DMF solution containing Et4NClO4 with a platinum cathode and a zinc anode. The reaction of 2-bromomethyl-1, 4-dibromo-2-butene (1) with aldehydes or ketones in the presence of the electrogenarated reactive zinc (EGZn) in DMF at 0 °C gave the corresponding isoprenylated alcohols (3a-3n) in good yields.

Time‐resolved optical emission spectroscopy, with a resolution of ≂10 ns, was used to investigate the formation of excited photofragments during pulsed ArF excimer‐laser irradiation of gaseous aluminum bromide. The solid Al2Br6 source was maintained at 50 °C and Ar used as a carrier gas to provide an aluminum bromide partial pressure of ≂3×10−6 Torr (4×10−4 Pa). The total pressure in the reactor was typically 300 mTorr (40 Pa). Following the laser pulse, emission was observed from the Al 4s 2S1/2→3p 2P1/2 and 4s 2S1/2→3p 2P3/2 transitions at 394 and 396 nm, respectively. The decay of the Al emission intensity IAl was convoluted with the temporal shape of the excitation pulse since the radiative lifetime of the Al 2S state, 6.8 ns, was less than the laser pulse width, ≂20 ns. The rise time of IAl, on the other hand, was

Transparent conducting thin films of indium tin oxide (ITO) have been deposited by d.c. reactive planar magnetron sputtering by using metal InSn alloy target in an ArO2 gas mixture. The study demonstrates that the deposition on unheated substrates achieved sheet resistance of as low as about 50–60 Ω/□ (or a resistivity of abouts 7 × 10−4 Ω cm), and visible transmission of about 90% for a wavelength of 420 nm. The effects of heat treatment at 450 °C in air depends on the deposition conditions of the as-deposited ITO films. Although annealing improves the properties of as-deposited ITO films which were deposited with non-optimum conditions, the optimized condition for the formation of the film in the as-deposited state is essential to obtain a high quality transparent conducting coating.

The reaction of 2-bromomethyl-1,4-dibromo-2-butene (1) with various aldehydes and ketones in tetrahydrofuran containing inc powder under reflux gave the corresponding isoprenylated alcohols 3a-o in one step in good yields. The synthesis of ipsdienol (3e) and ipsenol (3c) was achieved by the present method starting from 3-methyl-2-butenal (2e) and isovaleraldehyde (2c)

Reactive zinc metal can be prepared by the electrolysis of a DMF solution containing Et4NClO4 with a platinum cathode and a zinc anode. The reaction of 2-bromomethyl-1, 4-dibromo-2-butene (1) with aldehydes or ketones in the presence of the electrogenarated reactive zinc (EGZn) in DMF at 0 °C gave the corresponding isoprenylated alcohols (3a-3n) in good yields.

For decoherence processes induced by weak interactions with the environment, a general quantum channel with one noise parameter has been formulated. This channel is called low-noise channel and very useful for investigating the parameter estimation in the leading order. In this paper, we formulate the low-noise channel with multiple unknown parameters in order to address the simultaneous achievability of the Cram{\'e}r-Rao bound for the parameters estimation. In general, the simultaneous achievement of the Cram{\'e}r-Rao bound for multi-parameter estimations suffers from non-commutativity of optimal measurements for respective parameters. However, with certain exceptions, we show that the Cram{\'e}r-Rao bound for output states of dissipative low-noise channels can be always attained in the first order of the parameters as long as D \leq N-1, where D and N denote the number of the parameters and the dimension of the system, respectively. This condition is replaced by D \leq N^{2}-1 if it is allowed to set the entanglement with ancilla systems in its input state and to perform the non-local measurement on the composite system., Comment: 22 pages

In this study, we evaluated the current effectiveness of 11 beta-lactam antibiotics for treatment of orofacial odontogenic infections by determining the antimicrobial susceptibility of the major pathogens. The antimicrobial susceptibilities of viridans streptococci (n = 47), Peptostreptococcus (n = 67), Porphyromonas (n = 18), Fusobacterium (n = 57), black-pigmented Prevotella (n = 59) and non-pigmented Prevotella (n = 47) isolated from pus specimens of 93 orofacial odontogenic infections to penicillin G, cefmetazole, flomoxef, cefoperazone, cefoperazone/sulbactam, ceftazidime, cefpirome, cefepime, cefoselis, imipenem and faropenem were determined using the agar dilution method. Penicillin G, most cephalosporins, imipenem and faropenem worked well against viridans streptococci, Peptostreptococcus, Porphyromonas and Fusobacterium. Penicillin G and most cephalosporins, including fourth-generation agents, were not effective against beta-lactamase-positive Prevotella, though they were effective against beta-lactamase-negative strains. Cefmetazole, cefoperazone/sulbactam, imipenem and faropenem expressed powerful antimicrobial activity against beta-lactamase-positive Prevotella. In conclusion, penicillins have the potential to be first-line agents in the treatment of orofacial odontogenic infections. Most of the other beta-lactam antibiotics, including fourth-generation cephalosporins, were not found to have greater effectiveness than penicillins. In contrast, cefmetazole, cefoperazone/sulbactam, imipenem and faropenem were found to have greater effectiveness than penicillins.

We recently reported the beta-lactamase production and antimicrobial susceptibility of anaerobic gram-negative rods isolated from pus specimens of 93 orofacial odontogenic infections. In this report, we determine the bacteriology and antimicrobial susceptibility of bacteria other than anaerobic gram-negative rods, mainly gram-positive cocci, isolated from the same specimens. Streptococcus constellatus and Peptostreptococcus micros were frequent isolates from all types of infection examined. Peptostreptococcus prevotii, Corynebacterium species, and Eubacterium species were recovered only from dentoalveolar infections, while Gemella morbillorum was found more frequently in periodontitis than in the other infections. beta-Lactamase-positive strains were detected only in staphylococci. Ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, imipenem, erythromycin, clindamycin and levofloxacin showed high susceptibility rates (or = 77%) against viridans streptococci, Peptostreptococcus and Gemella. Minocycline showed a high MIC90 value against viridans streptococci (32 microg/ml), and metronidazole was effective against Peptostreptococcus and Gemella. These results provide useful information for the treatment of orofacial odontogenic infections.

The reaction of 2-bromomethyl-1,4-dibromo-2-butene (1) with various aldehydes and ketones in tetrahydrofuran containing inc powder under reflux gave the corresponding isoprenylated alcohols 3a-o in one step in good yields. The synthesis of ipsdienol (3e) and ipsenol (3c) was achieved by the present method starting from 3-methyl-2-butenal (2e) and isovaleraldehyde (2c)

The incidence of beta-lactamase production in anaerobic gram-negative rods isolated from 93 pus specimens of orofacial odontogenic infections and the antimicrobial susceptibility of these isolates against 11 antibiotics were determined. A total of 191 anaerobic gram-negative rods were isolated from the specimens. Beta-lactamase was detected in 35.6% of the black-pigmented Prevotella and 31.9% of the nonpigmented Prevotella. However, no strains among the other species isolated produced beta-lactamase. Ampicillin, cefazolin and cefotaxime showed decreased activity as regards beta-lactamase-positive Prevotella strains, whereas the activity of ampicillin/sulbactam, cefmetazole, and imipenem continued to be effective against such strains. All tested beta-lactam antibiotics were effective against Porphyromonas and Fusobacterium. Erythromycin showed decreased activity against nonpigmented Prevotella and Fusobacterium. Clindamycin, minocycline and metronidazole were powerful antibiotics against which anaerobic gram-negative rods could be tested. The present study showed that beta-lactamase-positive strains were found more frequently in the Prevotella strains than in any of the other species of anaerobic gram-negative rods. The effectiveness of adding sulbactam to ampicillin was demonstrated, as well as the difference in cephalosporin activity against beta-lactamase-positive strains.

Sap analysis is an effective method for diagnosing the nutritional status of field crops in order to determine appropriate fertilizer application for stable yield, high quality and low load to the environment. We conducted field experiments on potatoes to determine the sap properties of leaf petioles and to determine the optimum values of nitrogen and phosphorus for diagnosis in potato. The weight ratios of extracted sap to leaf petiole were 0.22 – 0.37. The NO3-N concentration in the petiole sap was nearly the same as that in the leaf petiole, but the inorganic P concentration in the petiole sap was lower than that in the leaf petiole. NO3-N and inorganic P concentrations in the sap were a good reflection of the plant nutritional status of nitrogen and phosphorus at the bud sprouting stage. For sufficient yield and quality, the optimum value of NO3-N concentration in the sap of leaf petiole at the bud sprouting stage was estimated to be 1.3 – 1.5 g L−1, and that of inorganic P was estimated to be about 100 mg L−1.

The molar ratio of branched-chain amino acids to tyrosine (BTR) correlates well with the Fischer ratio, and can be measured in a short period of time. It is regarded as the method of analysis that will eventually replace the Fischer ratio. But clinical significance of BTR in terms of acute liver disorders has not been examined thoroughly as of yet. In this study, we measured BTR of 34 patients with acute hepatitis, and examined the transition of the acute period of acute hepatitis and its recovery process. Thirty-four patients diagnosed with acute viral hepatitis became subjects of examination (16 patients of A type, 15 patients of B type, 1 patient of C type, 2 patients of non-A, non-B, non-C type). Out of the 34 patients, 11 were in serious stages (HPT under 40%), including 3 in fulminant condition. By using preserved serum obtained during the acute period (within 1 week of the highest transaminase value), recovery period (within 4 weeks), and treatment period (3 months and later), measurements were conducted with Diacolor:BTR (enzymatic analysis, ONO Pharmaceutical Co., Ltd.), and the results were compared with those of 50 healthy subjects (25 men, 25 women). BTR correlated well with the Fischer ratio for chronic hepatic patients, and with albumin (Alb), PT, and ICGR15 as well, proving that it is useful as an indicator of hepatic reserve ability. But BTR has not been thoroughly examined as it relates to acute liver disorders. In this study, BTR fell in the acute period, correlating with the serious period, proving that it is a useful indicator. For acute liver damage, BTR supports conventional indicators (Alb, Ch-E, HGF, etc.) for assessing serious damage. Also, it has been suggested that measuring the passage of BTR could be the indicator of true recovery, including amino acid metabolism for liver disorders.

G proteins transmit signals from cell surface receptors to intracellular effectors. The intensity of the signal is governed by the rates of GTP binding (leading to subunit dissociation) and hydrolysis. Mutants that cannot hydrolyze GTP (e.g. GsalphaQ227L, Gi2alphaQ205L) are constitutively activated and can lead to cell transformation and cancer. Here we have used a genetic screen to identify intragenic suppressors of a GTPase-deficient form of the Galpha in yeast, Gpa1(Q323L). Sequencing revealed second-site mutations in three conserved residues, K54E, R327S, and L353Delta (codon deletion). Each mutation alone results in a complete loss of the beta gamma-mediated mating response in yeast, indicating a dominant-negative mode of inhibition. Likewise, the corresponding mutations in a mammalian Gi2alpha (K46E, R209S, L235Delta) lead to inhibition of Gbeta gamma-mediated mitogen-activated protein (MAP) kinase phosphorylation in cultured cells. The most potent of these beta gamma inhibitors (R209S) has no effect on Gi2alpha-mediated regulation of adenylyl cyclase. Despite its impaired ability to release beta gamma, purified recombinant Gpa1(R327S) is fully competent to bind and hydrolyze GTP. These mutants will be useful for uncoupling Gbeta gamma- and Galpha-mediated signaling events in whole cells and animals. In addition, they serve as a model for drugs that could directly inhibit G protein activity and cell transformation.

To investigate the emergence of rifampin resistance in Rhodococcus equi strains isolated from foals and their environment in Japan, we compared the in vitro antimicrobial susceptibilities to rifampin of 640 isolates from 64 infected foals and 98 soil isolates from their horse-breeding farms. As a control, 39 human isolates from patients with and without AIDS were also tested for susceptibility to rifampin. All of the isolates showed rifampin sensitivity, except isolates from one infected foal and two patients with AIDS that showed rifampin resistance. To investigate the emergence of rifampin-resistant R. equi in the infected foal, which had received rifampin monotherapy for a month before euthanasia, 99 isolates of R. equi from the lesions and 20 isolates from the intestinal contents of the one foal with rifampin-resistant organisms were analyzed for rifampin susceptibilities, pathogenicities, and ribotypes. Of the 99 isolates from the lesions, all of which were virulent R. equi strains containing a virulence plasmid with a size of 85 or 90 kb, 90 (91%) isolates were rifampin resistant (MIC, > or = 12.5 microg/ml). On the other hand, of the 20 isolates from the intestinal contents, 11 (55%) isolates showed rifampin resistance (MIC, > or = 25 microg/ml), and 5 of them were avirulent R. equi strains. Among these 101 rifampin-resistant R. equi isolates with and without virulence plasmids characterized by ribotyping, 58 were type I, 20 were type II, 11 were type III, and 12 were type IV. These results demonstrated that at least eight different rifampin-resistant R. equi strains emerged concurrently and respectively from the different lesions and intestinal contents of the infected foal.

The antihypertensive and cough suppressant mechanisms of DU-1777 ((2S,3aS,7aS)-1-(N2-nicotinoyl-L-lsyl-gamma-D-glutamyl )octahydro-1H-indole-2 -carboxylic acid, CAS 116662-73-8), a new long-acting angiotensin-1-converting enzyme (ACE) inhibitor, were investigated in vivo and in vitro. The antihypertensive effects of DU-1777 at 10 mg/kg p.o. and cromakalim at 0.3 mg/kg p.o. were partially (about 60%) or fully antagonized by glibenclamide at 10 mg/kg i.v. in 2-kidney, 1-clip renal hypertensive rats (2K-1C RHR). The antihypertensive effects of a Ca blocker (nifedipine) and other ACE inhibitors (captopril, alacepril, enalapril, lisinopril, imidapril and quanapril) were not antagonized by glibenclamide. In deoxycorticosterone acetate-salt hypertensive rats (DOCA-HR), the antihypertensive effects of DU-1777 at 3-30 mg/kg p.o. were fully antagonized by glibenclamide. However, in vitro, DU-1777 (10(-6)-10(-3) mol/l) did not affect aortic ring contractions induced by high K (30 mmol/l). In guinea pig, citric acid induced cough was increased by ACE inhibitors, captopril, alacepril, enalapril and lisinopril (10 and 30 mg/kg p.o.). DU-1777 had a tendency to decrease citric acid induced cough and the effect was antagonized by glibenclamide. These results suggest that while DU-1777 itself does not open ATP-dependent K channel, it indirectly produces these effects through unknown mechanisms in vivo. Moreover, these effects contributed to the antihypertensive effect in DOCA-HR and cough suppressant effect in guinea pigs.

Monatepil maleate (CAS 103377-41-9, AJ-2615), a new derivative of dihydrodibenzothiepins, showed dose-dependent inhibition of Ca2+ current (ICa) in single cardiac cells isolated from guinea-pig ventricle. ICa was elicited by depolarization from -40 mV to +10 mV at 0.2 Hz. IC50 value of monatepil for the peak ICa at +10 mV was 18.7 nmol/l. The ICa inhibition was still sustained 30 min after washout, indicating that monatepil had long lasting activity in the mammalian single muscle cell.

The antihypertensive properties of a new long-acting, angiotensin-I-converting enzyme (ACE) inhibiting agent, (2S,3aS,7aS)-1-(N2-nicotinoyl-L-lysyl-gamma-D-glutamyl) octahydro-1H-indole-2-carboxylic acid (CAS 116662-73-8, DU-1777), were investigated orally in various experimental models of hypertension in comparison to a standard ACE inhibitor, lisinopril. The hypotensive potency of DU-1777 was not as marked as that of lisinopril in renin-dependent hypertensive models, i.e., two-kidney one-clip renal hypertensive rats (2K-1C RHR) (ED-20mmHg: 3.1 versus 1.0 mg/kg) or two-kidney two-clip renal hypertensive dogs (2K-2C RHD) (ED-20 mmHg: 2.5 versus 1.0 mg/kg), though the actions of the two drugs were both long-lasting and dose-related. When spontaneously hypertensive rats (SHR) were used, however, DU-1777 was as active as lisinopril (ED-20 mmHg: 17.9 versus 13.6 mg/kg). The most distinguishing results with DU-1777 were its hypotensive effects in renin-independent hypertensive models. In contrast to lisinopril, the drug produced a sustained and dose-related hypotensive effect in DOCA salt hypertensive rats (DOCA-HR) and one-kidney one-clip renal hypertensive rats (1K-1C RHR). There exists an inconsistency between the long duration of the agent's hypotensive action in all tested hypertensive models and its short duration of ACE inhibiting activity as demonstrated both in vivo and ex vivo. The sustained antihypertensive action of DU-1777 cannot be reasoned solely with respect to ACE inhibition, suggesting some additional mechanisms of action yet to be defined.

Basal defined medium (BDM) containing vitamins, minerals and seven amino acids--(/L) tryptophan 0.1 g, methionine 0.2 g, valine 0.3 g, isoleucine 0.3 g, proline 0.3 g, leucine 0.4 g and cysteine 0.5 g--which appeared to be essential for good growth of Clostridium difficile was prepared. Addition of glycine 0.2 g/L and threonine 0.4 g/L to BDM produced better growth of strain VPI 10463, and this defined medium was designated minimum amino acid-defined medium (MADM). Production of toxins A and B by strain VPI 10463 in 6 x MADM containing (/L) tryptophan 0.6 g, methionine 1.2 g, valine 1.8 g, isoleucine 1.8 g, proline 1.8 g, leucine 2.4 g, cysteine 0.5 g, glycine 0.2 g and threonine 0.4 g, was much greater than in MADM. Toxin production by 20 C. difficile strains was examined in two defined media--6 x MADM and complete amino acid-defined medium (CADM) containing 18 amino acids--and one complex medium, modified brain heart infusion medium (m-BHI). Simultaneous production of toxins A and B by all test strains was demonstrated in m-BHI and the two defined media. It was also shown that 6 x MADM was generally better than CADM and as effective as m-BHI for stimulating toxin production by 13 strains. This defined medium would be useful for studies on the physiology, metabolism and pathogenicity of C. difficile.

Antianginal effects of monatepil ([(+-)-N-(6,11-dihydrodibenzo[b,e]thiepin-11-yl)-4-(4-fluor ophenyl)-1-piperazinebutanamide]monomaleate, AJ-2615, CAS 10337-41-9), a new calcium antagonist, were evaluated in experimentally induced myocardial ischemia in anesthetized rats and compared with those of diltiazem. Ischemic electrocardiogram change (ST elevation) and reduction of myocardial tissue oxygen tension were induced by intracoronary arterial administration of U-46619 ((5Z,9a,11a,13E,15(S))-9,11-(methano-epoxy)prosta-5,13-di en-1-oic acid) (10 micrograms/kg), a stable thromboxane A2 agonist. The ST elevation induced by U-46619 was significantly prevented by monatepil pretreatment (0.1 mg/kg i.v.), and to a lesser extent by diltiazem (0.3 mg/kg i.v.). Moreover, the decrease in myocardial tissue oxygen tension at the time of ST elevation after U-46619 was inhibited by monatepil pretreatment (0.3 mg/kg i.v.). These results indicate that monatepil exerts a more potent preventive effect against U-46619-induced myocardial ischemic changes than diltiazem and suggest that monatepil has potential for treating vasospastic angina.

To clarify whether the inhibitory effect of zonisamide (Excegran, CAS 68291-97-4) on carbonic anhydrase contributes to its anticonvulsant activity, the anticonvulsant activity of 7-methylated zonisamide, a zonisamide analogue which has the same potency of activity as zonisamide in inhibiting carbonic anhydrase in vitro, has been examined. The study using mice did not reveal 7-methylated zonisamide to have any anticonvulsant activity even though its brain concentration level was more than two times the minimal effective concentration of zonisamide. These findings indicate that the anticonvulsant effect of zonisamide is derived from a mechanism(s) other than inhibition of carbonic anhydrase.

The effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b,e]thiepin-11-yl)-4-(p-fluor ophenyl)-1- piperazinebutyramide]maleate, AJ-2615, CAS 103377-41-9), a new calcium antagonist, on cardiac function and myocardial oxygen supply and demand were examined. 1. Monatepil reduced the spontaneous beats of isolated rabbit atria at the concentration of 3 x 10(-6) and 10(-5) mol/l. Monatepil decreased the contractile force of papillary muscles in a concentration-dependent manner (3 x 10(-8)-10(-5) mol/l). 2. Monatepil (0.3 mg/kg i.v.) slightly decreased heart rate in anesthetized open-chest dogs. This drug (0.1, 0.3 mg/kg i.v.) increased cardiac output and decreased blood pressure and total peripheral resistance. Monatepil decreased left ventricular dP/dtmax and slightly increased left ventricular end-diastolic pressure. 3. Monatepil (0.1-1.0 mg/kg i.v.) did not affect the PR interval, QRS duration and QTc interval of electrocardiograms in anesthetized dogs, whereas diltiazem (0.3 and 1.0 mg/kg i.v.) markedly prolonged the PR interval. 4. Monatepil (0.1-0.3 mg/kg i.v.) increased coronary blood flow (CoBF) and decreased myocardial oxygen consumption (MOC) and extraction. 5. Monatepil and diltiazem showed almost the same effects on cardiac function and myocardial oxygen supply and demand, but the negative chronotropic and negative dromotropic effects of monatepil were less potent than those of diltiazem.

A collection of 28 strains of Vibrio cholerae non-O1 isolated during a 3-year period (1989-1991) from hospitalised patients with acute diarrhoea in Calcutta, India, were examined with regard to virulence-associated factors. Of the 28 isolates (each representing a case), 18 were isolated as the sole infecting agent; the remaining 10 were recovered as co-cultures from cases infected with V. cholerae O1. Of the strains isolated in this study, 82% could be serotyped, with serovars O5 (32.1%), O11 and O34 (14.3% each) predominant. Serovars O7, O14, O34, O39 and O97 were associated exclusively with sole infections. Two strains of V. cholerae non-O1 produced anti-cholera toxin IgG-absorbable cholera toxin (CT). Both CT-producing V. cholerae non-O1 strains hybridised with the DNA probe specific for the zonula occludens toxin (ZOT) but none of the remaining 26 strains hybridised with the ZOT probe. The majority of the strains were cytotoxic for CHO, HeLa and Vero cells, with end-point titres of 4-512. Fewer strains produced a cytotonic effect, with end-point titres of 2-16. Of the 28 strains of V. cholerae non-O1 examined, 75%, 75%, 25% and 14.3% produced haemolysin that was active against erythrocytes of rabbit, sheep (Eltor haemolysin), chicken and man, respectively. Strains that produced a haemolysin active against both rabbit and sheep erythrocytes were dominant (35.7%). Ten (35.7%) of the 28 strains examined showed cell-associated haemagglutinating activity on human blood. Of the 10 strains, nine were isolated as sole pathogen and only one strain was associated with mixed infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b, e]thiepin-11-yl)-4-(p-fluorophenyl)-1-piperazinebutyramide]m aleate, AJ-2615, CAS 103377-41-9), a novel calcium antagonist, on the cardiac conduction system were compared by electrocardiography with those of the existing calcium antagonists (diltiazem, verapamil and nifedipine) in isolated rabbit heart preparations in vitro and in anesthetized and conscious dogs in vivo. Monatepil (10(-7) mol/l) prolonged the atrio-His bundle conduction time (AH interval) in the Langendorff perfused rabbit heart, like diltiazem, verapamil and nifedipine. This prolongation was decreased to 1/10 in the presence of 3.6% bovine serum albumin. In anesthetized dogs, monatepil (0.1-1.0 mg/kg i.v.), unlike diltiazem and verapamil, did not prolong AH interval. In conscious dogs, monatepil even at 100 mg/kg p.o. did not affect electrocardiograms. At the high dose of 300 mg/kg p.o., only a slight prolongation of the QT interval was found, but the QTc interval was not affected. Diltiazem at 10 mg/kg p.o. caused a prolongation of the PR interval and a disappearance of QRS waves. In conscious renal hypertensive dogs, repeated administration of monatepil (10 mg/kg/d p.o. for 29 days) had little effect on the conduction system of the heart examined by electrocardiograms, albeit a persistent fall in blood pressure continued throughout the administration period. The above results suggest that monatepil is a highly safe drug in the treatment of hypertension.