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1.
Oecologia ; 194(3): 455-463, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33064215

ABSTRACT

Sacoglossan sea slugs can 'steal' chloroplasts from their algal food and use them for photosynthesis (kleptoplasty). Although it has been shown that light has positive effects on survival and body size retention of some sacoglossans likely through photosynthesis, it is unknown whether light affects their fitness components such as number of offspring or offspring size. Moreover, whether the effects of light extend over the sacoglossans' lifetime has been unexplored. To assess such long-term effects of light intensity and food availability on fitness components, we conducted a 15.9-week laboratory experiment using Elysia atroviridis under a combination of two light intensities (low or high) and two food conditions (with or without food). The total number of eggs laid was greater in the presence of both strong light and food than in other conditions, suggesting positive effects of both light intensity and food availability. The shell height at hatch was also largest in the presence of strong light and food. Larval rearing experiments showed that the size difference at hatch between conditions corresponded to a 1.19-1.93 days growth and 7.9-18.1% survival increase. Thus, positive effects of light and food on the fitness components extend over the lifetime of E. atroviridis.


Subject(s)
Gastropoda , Photosynthesis , Animals , Chloroplasts/metabolism , Food
2.
Ecology ; 98(4): 1093-1103, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28112400

ABSTRACT

Accurately evaluating the strengths of direct (i.e., consumptive and non-consumptive) effects and indirect (density- and trait-mediated) interactions is crucial for understanding the mechanisms of the maintenance and dynamics of an ecosystem. However, an in situ evaluation has not been conducted for a long enough period of time to fully consider the seasonality and life histories of the community components. We conducted a 9-month (from summer to spring) field experiment in an intertidal rocky shore ecosystem involving the carnivorous snail, Thais clavigera, its prey, the limpet Siphonaria sirius, and their resources, the cyanobacterium (blue-green alga) Lithoderma sp. and the green algae Ulva spp. From summer to autumn, the predation pressure was high, and the consumptive and non-consumptive effects of the predator had opposite (positive and negative, respectively) effects on the prey. Both the density- and trait-mediated indirect interactions decreased the coverage of Lithoderma and increased the coverage of Ulva. As the predation pressure decreased in autumn, the predator affected both the adults and the new recruits of the prey. The trait-mediated interactions still existed, but the density-mediated interactions were not detected. From winter to spring, no direct effects or indirect interactions were detected because of the low predation pressure. Our investigation highlights previously unnoticed processes-showing that the strengths of the direct effects and indirect interactions fluctuate greatly with the seasonality of the ecosystem components.


Subject(s)
Ecosystem , Food Chain , Animals , Predatory Behavior , Seasons , Snails
3.
Antimicrob Agents Chemother ; 60(5): 3001-6, 2016 05.
Article in English | MEDLINE | ID: mdl-26953205

ABSTRACT

Gram-negative bacteria are evolving to produce ß-lactamases of increasing diversity that challenge antimicrobial chemotherapy. OP0595 is a new diazabicyclooctane serine ß-lactamase inhibitor which acts also as an antibiotic and as a ß-lactamase-independent ß-lactam "enhancer" against Enterobacteriaceae Here we determined the optimal concentration of OP0595 in combination with piperacillin, cefepime, and meropenem, in addition to the antibacterial activity of OP0595 alone and in combination with cefepime, in in vitro time-kill studies and an in vivo infection model against five strains of CTX-M-15-positive Escherichia coli and five strains of KPC-positive Klebsiella pneumoniae An OP0595 concentration of 4 µg/ml was found to be sufficient for an effective combination with all three ß-lactam agents. In both in vitro time-kill studies and an in vivo model of infection, cefepime-OP0595 showed stronger efficacy than cefepime alone against all ß-lactamase-positive strains tested, whereas OP0595 alone showed weaker or no efficacy. Taken together, these data indicate that combinational use of OP0595 and a ß-lactam agent is important to exert the antimicrobial functions of OP0595.


Subject(s)
Azabicyclo Compounds/pharmacology , Cephalosporins/pharmacology , Escherichia coli/drug effects , Klebsiella pneumoniae/drug effects , Lactams/pharmacology , Thienamycins/pharmacology , Cefepime , Escherichia coli/metabolism , Klebsiella pneumoniae/metabolism , Meropenem , Microbial Sensitivity Tests , Piperacillin/pharmacology , beta-Lactamases/metabolism
4.
Jpn J Antibiot ; 69(4): 265-290, 2016 Aug.
Article in English, Japanese | MEDLINE | ID: mdl-30226954

ABSTRACT

We conducted the post-marketing surveillance of tebipenem pivoxil (Orapeneme fine granules 10% for pediatric), an oral carbapenem antibacterial agent, to investigate changes in bacterial susceptibility against tebipenem (TBPM). Bacterial strains used in this surveillance were methicillin-susceptible Staphylococcus aureus (MSSA: 303 strains), Streptococcus pneumoniae (554 strains), other Streptococcus spp. (242 strains: including Streptococcus pyogenes 133 strains), Moraxella catarrhalis (306 strains) and Haemophilus influenzae (506 strains) isolated from pediatric patients in 15 medical facilities in Japan between April 2010 and March 2015. Investigation was conducted three times (April 2010-March 2011, April 2012-March 2013 and April 2014-March 2015), and in any of these investigation periods, there were a large number of isolates from infants in terms of the frequency of isolates by age. The MIC90s of TBPM against MSSA, S. pneumoniae, other Streptococcus spp., M. catarrhalis and H. influenzae in these investigations were 0.015-0.03, 0.06, 0.008-0.015 (0.002 for S. pyogenes), 0.03 and 0.5-1 µg/mL, respectively, which were less than 2-fold, and a remarkable increase in MIC90 was not shown. On the other hand, the MIC50s of carbapenems including TBPM and penicillins against S. pneumoniae decreased to 1/4-1/8 during the investigation periods, and decreased gPRSP*¹ (48.7% - 26.1%) and increased gPISP (2x)*² (24.1% -+ 46.8%) were suggested to be involved in these changes in susceptibility. In S. pneumoniae, a decrease of macrolides-resistant strains due to mefA*³ (38.5% - 18.8%) and an increase of macrolides-resistant strains due to ermB*4 (41.7% - 62.4%) were noted. In H. influenzae, the frequencies of gBLNAR*5 and ß-lactamase-producing strains were about 60-70% and 7-9%, respectively, and a remarkable change in susceptibility was not shown. As a result of investigations in the susceptibility of clinical isolates collected from pediatric patients as post-marketing surveillance, there was no decrease in TBPM susceptibility noted.


Subject(s)
Bacterial Infections/drug therapy , Carbapenems/pharmacology , Adolescent , Anti-Bacterial Agents/pharmacology , Child , Child, Preschool , Genotype , Humans , Infant , Microbial Sensitivity Tests , Mutation
5.
J Antimicrob Chemother ; 70(10): 2779-86, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26089439

ABSTRACT

OBJECTIVES: The production of a growing diversity of ß-lactamases by Gram-negative bacteria challenges antimicrobial chemotherapy. OP0595, discovered separately by each of Meiji Seika Pharma and Fedora Pharmaceuticals, is a new diazabicyclooctane serine ß-lactamase inhibitor that also acts as an antibiotic and as a ß-lactamase-independent ß-lactam 'enhancer'. METHODS: Inhibitory activity against serine ß-lactamases and affinity for PBPs were determined using nitrocefin and Bocillin FL, respectively. MICs alone and in combination with ß-lactam agents were measured according to CLSI recommendations. Morphological changes in Escherichia coli were examined by phase-contrast microscopy. RESULTS: IC50s of OP0595 for class A and C ß-lactamases were <1000 nM, with covalent binding demonstrated to the active-site serine of CTX-M-44 and AmpC enzymes. OP0595 also had direct antibiotic activity against many Enterobacteriaceae, associated with inhibition of PBP2 and conversion of the bacteria into spherical forms. Synergy between OP0595 and ß-lactam agents was seen against strains producing class A and C ß-lactamases vulnerable to inhibition. Lastly, OP0595 lowered the MICs of PBP3-targeted partner ß-lactam agents for a non-ß-lactamase-producing E. coli mutant that was resistant to OP0595 itself, indicating ß-lactamase-independent 'enhancer'-based synergy. CONCLUSIONS: OP0595 acts in three ways: (i) as an inhibitor of class A and C ß-lactamases, covalently binding at their active sites; (ii) as an antibacterial, by inhibiting PBP2 of several Enterobacteriaceae; and (iii) as an 'enhancer' of ß-lactam agents that bind to other PBPs besides PBP2 for several Enterobacteriaceae. OP0595 has considerable potential to overcome resistance when it is combined with various ß-lactam agents.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/pharmacology , Lactams/pharmacology , beta-Lactamase Inhibitors/pharmacology , beta-Lactams/pharmacology , Anti-Bacterial Agents/chemistry , Azabicyclo Compounds/chemistry , Catalytic Domain , Drug Synergism , Enzyme Activation/drug effects , Escherichia coli/drug effects , Escherichia coli/enzymology , Escherichia coli/genetics , Humans , Hydrogen Bonding , Inhibitory Concentration 50 , Lactams/chemistry , Microbial Sensitivity Tests , Models, Molecular , Molecular Conformation , beta-Lactamase Inhibitors/chemistry , beta-Lactamases/chemistry , beta-Lactamases/metabolism , beta-Lactams/chemistry
6.
Jpn J Antibiot ; 67(1): 33-47, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24809207

ABSTRACT

The objective of this study was to predict the clinical bacteriological efficacy of antibiotics and to examine the pharmacodynamics (PD) characteristics of antibiotics against bacterial strains using a mechanism-based pharmacokinetic-pharmacodynamics (PK-PD) modeling developed on the basis of interaction between drug concentrations and antibacterial activities. Dynamic PD parameters (epsilon, gamma, EC50) and growth rate of organisms (lambda) were obtained from in vitro time-kill profile data of oral antibiotics, tebipenem pivoxil (TBPM-PI) and cefditoren pivoxil (CDTR-PI) against Streptococcus pneumoniae or Haemophilus influenzae. PD characteristics of both drugs against S. pneumoniae or H. influenzae were examined, which indicated TBPM was concentration-dependent as well as time-dependent, and CDTR was mainly time-dependent to exhibit their bactericidal activities. Next, we simulated TBPM and CDTR concentrations in plasma after oral administration according to the dosage regimen of each drug specified in package insert, using population pharmacokinetic parameters of both drugs in pediatric patients with infections. In addition, changes in viable in vivo bacterial counts in humans were simulated using dynamic PD parameters and mean plasma concentrations of each drug. As a result, simulated profile of viable counts of S. pneumoniae and H. influenzae were well corresponding to the bacteriological efficacy results in clinical double-blinded comparative study of TBPM-PI and CDTR-PI in oral administration to pediatric patients with acute otitis media. As mentioned in the above, it was considered to be possible to clarify the PD characteristics of TBPM and CDTR against each bacterial strain using the mechanism-based PK-PD model developed on the basis of interaction between drug concentrations and antibacterial activities, and to estimate the clinical bacteriological efficacy of those drugs.


Subject(s)
Anti-Bacterial Agents/pharmacokinetics , Otitis Media/drug therapy , Anti-Bacterial Agents/therapeutic use , Bacteria , Forecasting , Haemophilus Infections/drug therapy , Haemophilus influenzae , Humans , Pneumococcal Infections/drug therapy , Streptococcus pneumoniae
7.
J Antimicrob Chemother ; 68(1): 153-8, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22945917

ABSTRACT

OBJECTIVES: ME1071 is a maleic acid that inhibits metallo-ß-lactamases (MBLs). We examined its ability to potentiate different carbapenems against MBL-producing Enterobacteriaceae in relation to its inhibition kinetics. METHODS: Enterobacteriaceae and Acinetobacter isolates with IMP, VIM and NDM MBLs were tested; bacteria with other types of carbapenem resistance were used as controls. Chequerboard titrations were performed by CLSI agar dilution, carbapenemases were cloned into pET-28a(+) and purified by column chromatography, and kinetic parameters were determined by spectrophotometry. RESULTS: The key findings were: (i) the MICs of carbapenems varied widely among isolates with the same carbapenemase, but those with the NDM types were generally the most resistant; (ii) biapenem was the carbapenem least compromised by all MBL types, owing to weaker kinetic efficiency (k(cat)/K(m)) for hydrolysis, contingent on lower affinity (higher K(m)); (iii) MBLs were the only carbapenemases inhibited by ME1071, confirming its specificity of action; and (iv) irrespective of the partner carbapenem, synergy with ME1071 was least for organisms with NDM MBLs and most for those with IMP types, correlating with ME1071 having weakest affinity (highest K(i)) for NDM-1 and strongest affinity for IMP-1. CONCLUSIONS: ME1071 reduced the MICs of carbapenems for bacteria with NDM-1 enzyme though synergy was weaker than for bacteria with IMP and VIM metallo-enzymes; this correlated with ME1071 having weaker affinity for NDM-1 than IMP-1 and VIM-2. As the weakest MBL substrate carbapenem, biapenem was the easiest to protect.


Subject(s)
Acinetobacter/drug effects , Bacterial Proteins/antagonists & inhibitors , Carbapenems/administration & dosage , Enterobacteriaceae/drug effects , Maleates/administration & dosage , beta-Lactamase Inhibitors , Acinetobacter/enzymology , Bacterial Proteins/metabolism , Drug Synergism , Enterobacteriaceae/enzymology , Enzyme Inhibitors/administration & dosage , Humans , Maleates/chemistry , Microbial Sensitivity Tests/methods , beta-Lactamases/metabolism
8.
Ecology ; 94(10): 2311-20, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24358716

ABSTRACT

Climate warming accelerates the timing of flowering and insect pollinator emergence, especially in spring. If these phenological shifts progress independently between species, features of plant-pollinator mutualisms may be modified. However, evidence of phenological mismatch in pollination systems is limited. We investigated the phenologies of a spring ephemeral, Corydalis ambigua, and its pollinators (bumble bees), and seed-set success over 10-14 years in three populations. Although both flowering onset and first detection of overwintered queen bees in the C. ambigua populations were closely related to snowmelt time and/or spring temperature, flowering tended to be ahead of first pollinator detection when spring came early, resulting in lower seed production owing to low pollination service. Relationships between flowering onset time, phenological mismatch, and seed-set success strongly suggest that phenological mismatch is a major limiting factor for reproduction of spring ephemerals. This report demonstrates the mechanism of phenological mismatch and its ecological impact on plant-pollinator interactions based on long-term monitoring. Frequent occurrence of mismatch can decrease seed production and may affect the population dynamics of spring ephemerals.


Subject(s)
Bees/physiology , Corydalis/physiology , Pollination/physiology , Animals , Seasons , Time Factors
9.
Ecology ; 94(1): 51-61, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23600240

ABSTRACT

The limits on annual seed production have long been characterized as restriction by either pollination success or resource provision to seed development. This expected dichotomy between pollen and resource limitation is based on the assumption that reproductive resources are fixed, which is reasonable for semelparous species. In contrast, iteroparity can ease the constraints on reproductive output per breeding season, if resources can be either mobilized from past storage or borrowed against future performance. For perennial plants, these options allow enhanced reproductive investment in response to unusually good pollination, so that annual seed production may not be pollen or resource limited. We assessed demand-governed reproductive investment by manipulating both resource supply capacity (partial defoliation) and resource demand (pollination quality: fully self-pollination, fully cross-pollination, or combinations of partial self- and cross-pollination within the inflorescence) for a forest herb, Stenanthium occidentale, which is subject to strong pre-dispersal inbreeding depression. Insensitivity to partial defoliation indicated that reproductive output was not source regulated. Instead, demand by developing seeds governs resource distribution, as demonstrated by elevated photosynthate translocation to fruits on fully cross-pollinated plants and the ability of completely defoliated plants to produce seeds. Such contingent resource allocation eliminates a simple dichotomy between pollen receipt and resource availability as limits on annual seed production. Instead, such flexible reproductive investment allows iteroparous perennials to participate maximally in current reproduction (as determined by ovule production) following superior pollination, or to conserve resources for future reproduction following poor pollination.


Subject(s)
Magnoliopsida/physiology , Seeds/physiology , Alberta , Carbon , Ecosystem , Photosynthesis/physiology , Plant Leaves/physiology , Time Factors
10.
PLoS One ; 18(5): e0285893, 2023.
Article in English | MEDLINE | ID: mdl-37192208

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the pandemic of the coronavirus disease 2019 (COVID-19), resulting in a global lockdown in 2020. This stagnation in human activities ('anthropause') has been reported to affect the behaviour of wildlife in various ways. The sika deer Cervus nippon in Nara Park, central Japan, has had a unique relationship with humans, especially tourists, in which the deer bow to receive food and sometimes attack if they do not receive it. We investigated how a decrease and subsequent increase in the number of tourists visiting Nara Park affects the number of deer observed in the park and their behaviour (bows and attacks against humans). Compared with the pre-pandemic years, the number of deer in the study site decreased from an average of 167 deer in 2019 to 65 (39%) in 2020 during the pandemic period. Likewise, the number of deer bows decreased from 10.2 per deer in 2016-2017 to 6.4 (62%) in 2020-2021, whereas the proportion of deer showing aggressive behaviour did not change significantly. Moreover, the monthly numbers of deer and their bows both corresponded with the fluctuation in the number of tourists during the pandemic period of 2020 and 2021, whereas the number of attacks did not. Thus, the anthropause caused by the coronavirus altered the habitat use and behaviour of deer that have continuous interactions with humans.


Subject(s)
COVID-19 , Deer , Animals , Humans , Animals, Wild , SARS-CoV-2 , COVID-19/epidemiology , COVID-19/veterinary , Communicable Disease Control , Human Activities , Japan/epidemiology
11.
Ann Bot ; 109(1): 237-46, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22021817

ABSTRACT

BACKGROUND: The production of flowers, fruits and seeds demands considerable energy and nutrients, which can limit the allocation of these resources to other plant functions and, thereby, influence survival and future reproduction. The magnitude of the physiological costs of reproduction depends on both the factors limiting seed production (pollen, ovules or resources) and the capacity of plants to compensate for high resource demand. METHODS: To assess the magnitude and consequences of reproductive costs, we used shading and defoliation to reduce photosynthate production by fully pollinated plants of a perennial legume, Oxytropis sericea (Fabaceae), and examined the resulting impact on photosynthate allocation, and nectar, fruit and seed production. KEY RESULTS: Although these leaf manipulations reduced photosynthesis and nectar production, they did not alter photosynthate allocation, as revealed by (13)C tracing, or fruit or seed production. That photosynthate allocation to reproductive organs increased >190 % and taproot mass declined by 29 % between flowering and fruiting indicates that reproduction was physiologically costly. CONCLUSIONS: The insensitivity of fruit and seed production to leaf manipulation is consistent with either compensatory mobilization of stored resources or ovule limitation. Seed production differed considerably between the two years of the study in association with contrasting precipitation prior to flowering, perhaps reflecting contrasting limits on reproductive performance.


Subject(s)
Flowers/growth & development , Oxytropis/growth & development , Alberta , Biological Transport , Flowers/metabolism , Fruit/growth & development , Fruit/metabolism , Light , Oxytropis/metabolism , Plant Leaves/growth & development , Plant Leaves/metabolism , Plant Nectar/biosynthesis , Seeds/growth & development , Seeds/metabolism
12.
J Infect Chemother ; 18(2): 272-5, 2012 Apr.
Article in English | MEDLINE | ID: mdl-21968967

ABSTRACT

Bordetella pertussis is the etiological agent of whooping cough, a common cause of respiratory illness in both children and adults. In the present study, we investigated the bactericidal activity of four antiseptics-povidone-iodine (PVP-I), benzethonium chloride (BEC), chlorhexidine gluconate (CHG) and benzalkonium chloride (BAC)-against B. pertussis ATCC9797 and clinical isolates. Among the topical antiseptics, PVP-I, BEC, and BAC, PVP-I and BAC in particular, showed high bactericidal activity, whereas CHG had low activity. PVP-I gargle also showed high bactericidal activity, similar to topical PVP-I. However, BEC gargle had low bactericidal activity. Our results indicate that topical PVP-I and BAC, and PVP-I gargle would be useful as effective antiseptics against B. pertussis.


Subject(s)
Anti-Infective Agents, Local/pharmacology , Bordetella pertussis/drug effects , Administration, Topical , Benzalkonium Compounds/pharmacology , Benzethonium/pharmacology , Bordetella pertussis/isolation & purification , Chlorhexidine/analogs & derivatives , Chlorhexidine/pharmacology , Colony Count, Microbial , Humans , Mouthwashes/pharmacology , Povidone-Iodine/pharmacology , Whooping Cough/microbiology
13.
Antimicrob Agents Chemother ; 54(9): 3970-3, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20585130

ABSTRACT

In vitro activity of tebipenem, a new oral carbapenem antibiotic, against clinical Haemophilus influenzae isolates was compared with those of 8 reference agents. Isolates were classified into 6 resistance classes after PCR identification of beta-lactamase genes and ftsI gene mutations. For all isolates, the minimal concentration at which 90% of isolates were inhibited was lower for tebipenem than for the reference oral antibiotics, except for cefditoren. Tebipenem also showed excellent bactericidal activity against beta-lactamase-nonproducing, ampicillin-resistant isolates.


Subject(s)
Ampicillin Resistance/genetics , Carbapenems/pharmacology , Haemophilus influenzae/drug effects , beta-Lactamases/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/physiology , Drug Resistance, Bacterial/genetics , Haemophilus influenzae/enzymology , Haemophilus influenzae/genetics , Microbial Sensitivity Tests , Polymerase Chain Reaction , beta-Lactamases/genetics
14.
J Antimicrob Chemother ; 65(1): 37-45, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19889788

ABSTRACT

OBJECTIVES: To further understand the mechanism of intermediate-level glycopeptide resistance, resulting from multiple endogenous mutations, in both laboratory-derived and clinically isolated Staphylococcus aureus. METHODS: Laboratory-derived S. aureus strains were generated under selection using a variety of cell-wall-active antibiotics. Complete sequences of 27 genes, including 17 two-component histidine kinase sensors, were then compared with those of their susceptible parent strain. Further genetic analysis was performed on 125 clinical S. aureus isolates and 42 geographically diverse isolates of vancomycin-intermediate S. aureus (VISA). RESULTS: Selective pressure using imipenem resulted in single point mutations leading to amino acid substitutions in two genes: vraS, encoding a two-component histidine kinase sensor; and SA1702 (also called yvqF, located immediately upstream of vraS), encoding a conserved hypothetical protein. The accumulation of the mutation in two distinct proteins-MsrR, a peptide methionine sulphoxide reductase regulator, and TcaA, a teicoplanin-resistance-associated protein-correlated with further increases in the glycopeptide MIC. The prevalence of YvqF/VraSR mutants among 125 clinical isolates along with the corresponding teicoplanin MICs was as follows: 0% (0/39), < or =1 mg/L; 48.6% (17/35), 2 mg/L; 72.7% (24/33), 4 mg/L; 93.8% (15/16), 8 mg/L; and 100% (2/2), 16 mg/L. Genetic analysis of 42 VISA isolates also identified the predominant amino acid substitutions in YvqF/VraS: 9 isolates (21.4%) revealed mutations in YvqF, followed by 7 isolates with mutations in VraS (16.7%). CONCLUSIONS: Our findings provide novel insights into the high prevalence and genetic diversity of YvqF/VraSR mutants among clinical S. aureus isolates with reduced susceptibility to teicoplanin.


Subject(s)
Amino Acid Substitution/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Resistance, Bacterial , Glycopeptides/pharmacology , Mutation, Missense , Staphylococcus aureus/drug effects , DNA Mutational Analysis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA-Binding Proteins/genetics , Genetic Variation , Humans , Microbial Sensitivity Tests , Point Mutation , Prevalence , Selection, Genetic , Sequence Analysis, DNA , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification
15.
Jpn J Antibiot ; 63(3): 242-54, 2010 Jun.
Article in Japanese | MEDLINE | ID: mdl-20976880

ABSTRACT

Yearly changes in the susceptibility of clinical isolates to ulifloxacin (UFX) and other fluoroquinolones were examined through surveys over 3 periods. In the first survey, 534 strains derived from 19 species were collected from clinical specimens during 6 months from December 2003 to May 2004. In the same way, 805 strains were collected from December 2005 to May 2006 in the second survey, and 863 strains were from December 2007 to May 2008 in the third survey. Over these 3 study periods, the susceptibilities of fluoroquinolones against methicillin-susceptible Staphylococcus aureus and Escherichia coli were decreased. The isolation frequency of levofloxacin-nonsusceptible strain was increased from 0% to 11.8% and from 14.6% to 20.8%, respectively. MIC90s of UFX against these pathogens were also increased, but its MIC90 for E. coli was 2 to 4 times lower than that of levofloxacin. On the other hand, the susceptibility of strains of Klebsiella pneumoniae to UFX was increased. Among the fluoroquinolones tested, UFX showed the most potent activity against Pseudomonas aeruginosa, and no changes in the MIC90s occurred during the surveillance. Although one strain of Streptococcus pneumoniae isolated in the third study period showed levofloxacin-resistance (MIC, 8 microg/mL), there were nearly no changes in the MIC90s of any agents tested including UFX against S. pneumoniae during the surveillance. As for other bacterial species, a tendency to increase in resistance to UFX was not observed. The activity of UFX against Salmonella spp. and Shigella spp. was superior/equal to those of fluoroquinolones tested.


Subject(s)
Anti-Bacterial Agents/pharmacology , Dioxolanes/pharmacology , Fluoroquinolones/pharmacology , Piperazines/pharmacology , Product Surveillance, Postmarketing , Bacteria/drug effects , Drug Resistance, Bacterial , Humans , Microbial Sensitivity Tests
16.
J Appl Crystallogr ; 53(Pt 3): 679-685, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32684883

ABSTRACT

Exact and approximate mathematical formulas of equatorial aberration for powder diffraction data collected with an Si strip X-ray detector in continuous-scan integration mode are presented. An approximate formula is applied to treat the experimental data measured with a commercial powder diffractometer.

17.
J Plant Res ; 122(2): 171-81, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19156358

ABSTRACT

Light conditions on the floor of deciduous forests are determined by the leaf dynamics of canopy trees and gap formation. Such spatiotemporal variations of light availability should affect the resource partitioning strategies of understory herbs. Although rhizomatous species are common in understory, relationships between rhizome structure, vegetative growth, and sexual reproduction are unclear in terms of carbon allocation. We compared the photosynthetic characteristics and carbon translocation patterns in the under-canopy and light-gap sites between two summer-green perennial species: Cardamine leucantha with an annual long rhizome, and Smilacina japonica with a perennial short rhizome system. Flowering of both species occurs in early summer under decreasing light availability. In the light-gap, C. leucantha maintained high photosynthetic activity due to continuous leaf production, resulting in higher seed production than in the under-canopy. In contrast, the photosynthetic rate of S. japonica, producing leaves simultaneously, decreased with time irrespective of light conditions, resulting in stable seed production in both sites. Although seasonally decreasing light availability commonly restricts carbon assimilation of understory herbs, the responses of resource partitioning to variations in light availability depend greatly on the belowground structure of individual species.


Subject(s)
Light , Rhizome/physiology , Trees/physiology , Adaptation, Physiological , Biodiversity , Cardamine/physiology , Ecosystem , Photosynthesis/physiology , Plant Leaves/physiology
18.
Rinsho Byori ; 57(2): 124-30, 2009 Feb.
Article in Japanese | MEDLINE | ID: mdl-19317217

ABSTRACT

Urinary albumin (ALB) has been measured as a marker for the early detection of diabetic nephropathy. In 2004, Comper et al. developed a gel-filtration high-performance liquid chromatography (HPLC) procedure for the determination of urinary ALB. They demonstrated the presence in its albumin fraction of non immunoreactive ALB with the total molecular weight of a monomeric ALB that was non-reactive with the existing anti-ALB antibody, and reported that the level of urinary non-immunoreactive ALB was higher in diabetic patients than in normal subjects. In this study, we isolated urinary ALB from diabetic patients using an anti-ALB antibody-coupled affinity column to test its immunoreactivity. In some diabetic patients, the results of HPLC and turbidimetric immunoassay for urinary ALB were discrepant. Western blot analysis showed that ALB samples from such patients were contaminated with proteins other than ALB, and contained ALB, whose molecular weight became lower using a reductive procedure. In addition, the reactivity of ALB with anti-ALB antibody differed depending on whether it was in a reduced or non-reduced state. These results indicate that ALB in such patients is susceptible to structural changes due to disease-induced urinary factors and, thus, their urine contains ALB with an altered reactivity to antibody.


Subject(s)
Albuminuria , Diabetic Nephropathies/diagnosis , Aged , Biomarkers/urine , Chromatography, High Pressure Liquid , Female , Humans , Immunoassay , Male , Nephelometry and Turbidimetry
19.
Antimicrob Agents Chemother ; 52(5): 1880-3, 2008 May.
Article in English | MEDLINE | ID: mdl-18347113

ABSTRACT

Horizontal transfer of the mutated ftsI gene from beta-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae to a susceptible strain was examined in vitro under selection with nine oral beta-lactams (ampicillin, amoxicillin, cefprozil, cefuroxime, cefpodoxime, cefdinir, cefcapene, cefditoren, and tebipenem). Compared to the penicillins and the carbapenem, the cephalosporins showed a wide selection window for the genetic transfer.


Subject(s)
Bacterial Proteins/genetics , Haemophilus influenzae/drug effects , Penicillin-Binding Proteins/genetics , beta-Lactams/pharmacology , Ampicillin/pharmacology , Carbapenems/pharmacology , Cefdinir , Cephalosporins/pharmacology , Gene Transfer, Horizontal , Haemophilus influenzae/genetics , Mutation , Cefprozil
20.
Ecology ; 89(2): 321-31, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18409422

ABSTRACT

Light availability in the understory of deciduous forests changes drastically within the growing season due to the foliage dynamics of canopy trees. Because flowering phenology, photosynthetic characteristics, and fruiting success respond to such strong seasonality in light availability, we hypothesized that understory plants in such ecosystems should describe distinct phenological groups or syndromes where "syndrome" is defined only as a set of characteristics that co-occur. To identify these phenological syndromes, we studied the flowering phenology, fruit or seed set, and photosynthetic characteristics for 18 perennial understory herbaceous species that differed in reproductive strategy over eight years in a deciduous forest in northern Japan. Three phenological groups emerged from this study: (1) spring bloomers, flowering and fruiting before the completion of canopy closure; (2) early-summer bloomers, flowering during the progress of canopy closure and fruiting after canopy closure; and (3) late-summer bloomers, flowering and fruiting after canopy closure. The spring bloomers had high photosynthetic rates and high fruiting abilities, but the flowering time varied considerably among years due to yearly fluctuations of snowmelt date. Bumble bee-pollinated species of spring bloomers showed variable seed-set success, while fly-pollinated species showed relatively stable seed sets over the years. The early-summer bloomers showed low fruiting abilities irrespective of pollination success, reflecting severe resource limitation with decelerating light availability during fruit development. Although the late-summer bloomers showed low photosynthetic rates under low-light conditions, high fruit-set success was attained if pollination was sufficient. These results support our hypothesis that phenological syndromes may be found in deciduous forest understory plants. Given that reproductive success of bee-pollinated spring bloomers is highly susceptible to seasonal fluctuation, climate change may have its strongest impacts on this group.


Subject(s)
Bees/physiology , Photosynthesis/physiology , Plant Physiological Phenomena , Pollination/physiology , Reproduction/physiology , Animals , Biodiversity , Flowers/physiology , Fruit/physiology , Japan , Photoperiod , Seasons , Sunlight , Trees
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