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In Japan, three trematode species of the genus Azygia have been recorded: A. gotoi, A. perryii, and A. rhinogobii. Here, we report the first detection of A. hwangtsiyui in Japan, identified from the introduced snakehead Channa argus. This trematode was previously known only from the snakeheads in mainland China. Between 2015 and 2024, we sampled snakeheads and snails in Japan, collecting adult trematodes and rediae. Adult trematodes were identified morphologically as A. hwangtsiyui, a determination corroborated by molecular analyses of the COI and 28S rDNA regions. Rediae extracted from the snail Sinotaia quadrata histrica were also identified molecularly as A. hwangtsiyui, indicating the snail acts as an intermediate host. Juvenile trematodes from the short-spined Japanese trident goby Tridentiger brevispinis were also morphologically identified as A. hwangtsiyui, indicating that this goby acts as a paratenic host. Given the snakehead’s introduction to Japan between 1923 and 1924, the absence of records of later introductions, and the presence of both intermediate and paratenic hosts in Japan at that time, A. hwangtsiyui was likely introduced concurrently with the snakehead. As the detection of three COI haplotypes suggests multiple introductions, subsequent introductions via the aquarium trade or other pathways involving the transport of freshwater fish and mollusks from Asia to Japan are also plausible.
Herbicide options for selective control of monocot weeds in rice (Oryza sativa L.) have historically been limited to a few modes of action such as inhibitors of acetolactate synthase (e.g., penoxsulam, imazamox), photosystem II (e.g., propanil), and acetyl-CoA carboxylase (e.g., cyhalofop). Florpyrauxifen-benzyl (Rinskor™) is a synthetic auxin molecule introduced to the U.S. rice herbicide market in 2018, providing broad-spectrum weed control (monocots and dicots), including hard-to-control species such as barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], along with postemergence rice selectivity at very low use rates. Within the year of commercialization, field agronomists and academics identified E. crus-galli escapes in some areas where florpyrauxifen-benzyl had been sprayed. Further evaluation under controlled environments confirmed that those plants were able to survive florpyrauxifen-benzyl application at the label rate. Here, we identify the mechanism of resistance to florpyrauxifen-benzyl and penoxsulam in two E. crus-galli populations from Arkansas (AR-27) and Missouri (MO-18). Using high-resolution mass spectrometry, we compared the two resistant biotypes with known susceptible plants regarding their ability to metabolize florpyrauxifen-benzyl, florpyrauxifen-acid, and penoxsulam in planta. We discovered that the resistant plants share a common resistance mechanism to florpyrauxifen-benzyl and penoxsulam, involving hydrolysis of a methoxy group (likely mediated by a cytochrome P450 monooxygenase) followed by glucose conjugation. Given that penoxsulam has been widely used in rice fields for the past decade, these data suggest that some populations of E. crus-galli may have evolved resistance before the commercialization of florpyrauxifen-benzyl.
In June 2020, a large-scale food poisoning outbreak involving about 3000 elementary and junior high school students occurred in Yashio, Saitama, Japan. A school lunch was the only food stuff ingested by all of the patients. Escherichia coli serotype O7:H4 carrying the astA gene for enteroaggregative E. coli (EAggEC) heat-stable enterotoxin 1 (EAST1) was detected in faecal specimens from the patients, and sample inspection revealed its presence in a seaweed salad and red seaweed (Gigartina tenella) as one of the raw materials. Analysis of the antibiotic sensitivity of the isolates revealed resistance to ampicillin and cefotaxime. All isolates were confirmed to be of the same origin by pulsed-field gel electrophoresis after digestion with the restriction enzyme XbaI, and single nucleotide polymorphism analysis using whole genome sequencing. To our knowledge, this is the first report of a large-scale food poisoning caused by E. coli O7:H4, which lacks well-characterized virulence genes other than astA.
Wild poinsettia (Euphorbia heterophylla L.) is a troublesome broadleaf weed in grain production areas in South America. Herbicide resistance to multiple sites of action has been documented in this species, including protoporphyrinogen oxidase (PPO) inhibitors. We investigated the physiological and molecular bases for PPO-inhibitor resistance in a E. heterophylla population (RPPO) from Southern Brazil. Whole-plant dose–response experiments revealed a cross-resistance profile to three different chemical groups of PPO inhibitors. Based on dose–response parameters, RPPO was resistant to lactofen (47.7-fold), saflufenacil (8.6-fold), and pyraflufen-ethyl (3.5-fold). Twenty-four hours after lactofen treatment (120 g ha−1) POST, RPPO accumulated 27 times less protoporphyrin than the susceptible population (SPPO). In addition, RPPO generated 5 and 4.5 times less hydrogen peroxide and superoxide than SPPO, respectively. The chloroplast PPO (PPO1) sequences were identical between the two populations, whereas 35 single-nucleotide polymorphisms were found for the mitochondrial PPO (PPO2). Based on protein homology modeling, the Arg-128-Leu (homologous to Arg-98-Leu in common ragweed [Ambrosia artemisiifolia L.] was the only one located near the catalytic site, also in a conserved region of PPO2. The cytochrome P450 monooxygenase inhibitor malathion did not reverse resistance to lactofen in RPPO, and both populations showed similar levels of PPO1 and PPO2 expression, suggesting that metabolic resistance and PPO overexpression are unlikely. This is the first report of an Arg-128-Leu mutation in PPO2 conferring cross-resistance to PPO inhibitors in E. heterophylla.
Glufosinate inhibits glutamine synthetase (GS), a key enzyme for amino acid metabolism and photorespiration. Protoporphyrinogen oxidase (PPO) inhibitors block chlorophyll biosynthesis and cause protoporphyrin accumulation, a highly photodynamic intermediate. Both herbicides ultimately lead to plant death by a massive accumulation of reactive oxygen species (ROS) through different mechanisms. We investigated a potential synergistic effect by the mixture of the two herbicide mechanisms of action (MoAs). The tank mix between a low rate of glufosinate (280 g ai ha−1) with an ultra-low dose of saflufenacil (1 g ha−1) provided enhanced herbicidal activity compared with the products applied individually on Palmer amaranth (Amaranthus palmeri S. Watson). The synergism between the two herbicides was also confirmed by isobole analysis and field trials. The herbicide combination provided high levels of efficacy when applied at low temperature and low humidity. Mechanistically, glufosinate caused a transient accumulation of glutamate, the building block for chlorophyll biosynthesis. Consequently, inhibition of both GS and PPO resulted in greater accumulation of protoporphyrin and ROS, forming the physiological basis for the synergism between glufosinate and PPO inhibitors. While the synergy between the two herbicide MoAs provided excellent efficacy on weeds, it caused low injury to PPO-resistant waterhemp [Amaranthus tuberculatus (Moq.) Sauer] and high injury to both glufosinate-resistant and glufosinate-susceptible soybean [Glycine max (L.) Merr.]. Glufosinate enhances the activity of PPO inhibitors through glutamate and protoporphyrin accumulation, leading to increased levels of ROS and lipid peroxidation. The synergism between the two herbicide MoAs can help to overcome environmental effects limiting the efficacy of glufosinate. Future research is needed to optimize the uses for this herbicidal composition across different cropping systems.
Glyphosate-resistant (GR) goosegrass [Eleusine indica (L.) Gaertn.] was recently identified in Brazil, but its resistance mechanism was unknown. This study elucidated the resistance mechanism in this species and developed a molecular marker for rapid detection of this target-site resistance trait. The resistance factor for the resistant biotype was 4.4-fold compared with the glyphosate-susceptible (GS) in greenhouse dose–response experiments. This was accompanied by a similar (4-fold) difference in the levels of in vitro and in planta shikimate accumulation in these biotypes. However, there was no difference in uptake, translocation, or metabolism of glyphosate between the GS and GR biotypes. Moreover, both biotypes showed similar values for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) copy number and transcription. Sequencing of a 330-bp fragment of the EPSPS gene identified a single-nucleotide polymorphism that led to a Pro-106-Ser amino acid substitution in the enzyme from the GR biotype. This mutation imparted a 3.8-fold increase in the amount of glyphosate required to inhibit 50% of EPSPS activity, confirming the role of this amino acid substitution in resistance to glyphosate. A quantitative PCR–based genotyping assay was developed for the rapid detection of resistant plants containing this Pro-106-Ser mutation.
Unusual mafic rock fragments deposited in Plio-Pleistocene-aged marine sediments were recorded at Integrated Ocean Drilling Program (IODP) Site U1359, in Wilkes Land, East Antarctica. These fragments were identified from sediment layers deposited between c. 3 and 1.2 Ma, indicating a sustained supply during this time interval. Clinopyroxenes in these basalts are Al–Ti diopside–hedenbergite, uncommon in terrestrial magmatic rocks. A single strong peak in the Raman spectra of a phosphate-bearing mineral at 963 cm-1 supports the presence of merrillite. Although not conclusive, petrological traits and oxygen isotopic compositions also suggest that the fragments may be extra-terrestrial fragments affected by shock metamorphism. Nevertheless, it is concluded that the basaltic fragments incorporated in marine sediments at Site U1359 represent ice-rafted material supplied to the continental rise of East Antarctica, probably from the bedrocks near the proximal Ninnis Glacier. Further studies on Plio-Pleistocene sediments near Site U1359 are required to characterize the unusual mafic rocks described.
Due to the limited availability of selective herbicides to control Sumatran fleabane after soybean emergence, it is essential to develop new options that provide effective control prior to planting. A new herbicide formulation containing diclosulam+halauxifen-methyl was evaluated for effectiveness at two Sumatran fleabane plant heights (5 to 10 cm, and 10 to 50 cm) and for soybean selectivity when applied at 7 or 3 d before planting. Combined results from the two sites showed that diclosulam+halauxifen, applied either alone or in a tank mixture with glyphosate, and the tank mixture of diclosulam+2,4-D amine+glyphosate are effective at all rates tested to control Sumatran fleabane in preplant applications. Crop response was observed with applications 7 days before planting at only one of the sites. A rate-dependent crop response was observed for pre-plant applications performed 3 days before soybean planting. However, crop yield was not significantly affected for either timing across all rates. All rates tested of diclosulam+halauxifen in this study were considered safe to soybean.
The rapid spread of glyphosate-resistant sourgrass populations generates concern in the agricultural production sector in Brazil. Nonetheless, there is not much information related to the frequency and dispersion of sourgrass throughout recent years. We investigated the frequency and dispersion of glyphosate-resistant sourgrass populations in Brazilian agricultural regions as part of a larger-scale weed resistance monitoring study. A discriminatory rate of 960 g ae ha−1 of glyphosate was used on plants at the 2- to 3-tiller stage, originating from 2,593 populations of sourgrass sampled in 329 counties in 14 Brazilian states between 2012 and 2015. The dispersion of sourgrass populations originated in western Paraná State, next to the Paraguay border, where the first resistance case was reported. Its dispersion to the central region of Brazil, mainly in soybean-producing areas, is most likely a consequence of agricultural equipment movement and wind-mediated dispersal. Glyphosate-resistant sourgrass populations were found in every geographical region across all Brazilian states tested. These data highlight the importance of an appropriate weed resistance monitoring program to track the evolution and dispersion of resistance to mitigate these issues by focusing efforts regionally and raising awareness among stakeholders in each region.
Four microseconds long Ar3+ beam with injection energy of 15 keV/u has been injected into the Digital Accelerator of the High-Energy Accelerator Research Organization. Beam production, transportation, and injection are described as well as machine properties. Results of a free running experiment under static magnetic field and longitudinal confinement and acceleration under a fast ramping magnetic field are presented in detail with a brief discussion on the beam lifetime.
Strain in silicon on insulator (SOI) and strained-silicon(s-Si)/silicon–germanium (SiGe)/Si-substrate crystals is analysed by means of synchrotron X-ray microbeam diffraction. It is found that strain features of the s-Si/SiGe/Si crystals are much different from those of SOI crystals from the lattice tilt and lattice parameter distribution points of view. The two-dimensional lattice tilt maps obtained by scanning the synchrotron X-ray microbeam of about 1 μm in size on the sample surface are useful to study local strain distribution in those materials.
Crystallinity of area-selective Ge layer with a (0 0 1) surface grown on Si substrate has been investigated by means of diffractometry using a parallel X-ray microbeam. The measured lattice parameters of 〈0 0 1〉 direction were about 0.17% smaller than that of bulk Ge crystal. This tensile strain value was almost the same as the simulated ones that used the finite-element method.
Segmental duplications are enriched within many eukaryote genomes, and their potential consequence is gene duplication. While previous theoretical studies of gene duplication have mainly focused on the gene silencing process after fixation, the process leading to fixation is even more important for segmental duplications, because the majority of duplications would be lost before reaching a significant frequency in a population. Here, by a series of computer simulations, we show that purifying selection against loss-of-function mutations increases the fixation probability of a new duplicate gene, especially when the gene is haplo-insufficient. Theoretically, the probability of simultaneous preservation of both duplicate genes becomes twice the loss-of-function mutation rate (uc) when the population size (N), the degree of dominance of mutations (h) and the recombination rate between the duplicate genes (c) are all sufficiently large (Nuc>1, h>0·1 and c>uc). The preservation probability declines rapidly with h and becomes 0 when h=0 (haplo-sufficiency). We infer that masking deleterious loss-of-function mutations give duplicate genes an immediate selective advantage and, together with effects of increased gene dosage, would predominantly determine the fates of the duplicate genes in the early phase of their evolution.
Invasive pneumococcal disease (IPD) is of concern in Japan, where the heptavalent pneumococcal conjugate vaccine (PCV7) is unavailable. We determined serotypes, genotypes indicating β-lactam resistance, and antibiotic susceptibilities of 496 isolates from normally sterile sites in patients (193 children, 303 adults) from 186 institutions between August 2006 and July 2007. Disease presentations included sepsis (46·2%), pneumonia (31·5%), and meningitis (17·5%). Mortality was 1·4% in children and 22·1% in adults, many of whom had underlying diseases. In children, serotype 6B (22·5%) was followed by 19F (14·1%), and 14 (13·1%); potential coverages of PCV7 and PCV13 were 75·4% and 93·7%, respectively. In adults, serotype 12F (14·3%) was followed by 3 (11·3%), and 6B (10·3%); 23-valent polysaccharide vaccine (PPV23) coverage was 85·4%. Most serotype 12F strains were gPISP, with pbp2b gene alteration; carbapenem had an excellent MIC90. PCV7 is recommended for children and PPV23 for adults to increase prevention against IPD.
An experimental method is proposed for detecting the effects of positive natural selection on DNA polymorphisms. Since beneficial mutations are expected to increase in frequency faster than neutral mutations, variants which have reached high frequencies in a relatively short period could be linked to some beneficial mutation. D. melanogaster has a cosmopolitan polymorphic inversion -In(2L)t - whose age in some local populations has been estimated. Setting the age of In(2L)t as the upper limit for the age of variants, we searched for variants whose frequencies were possibly influenced by positive natural selection. We detected a single candidate whose frequency and distribution met the requirements imposed by our method.
A systematically peculiar molecular composition has been found in a nearby starburst galaxy M 82. Molecules related to grain surface formation and to production reactions favorable at high-temperature are deficient in M 82 among nearby galaxies with rich gas. These molecules are SO, SiO, NH3, HNCO, CH3OH, and CH3CN. Possible reasons for this peculiarity are discussed.
We use a novel ultra-high-speed video camera to study the initial stage of the impact of a solid sphere onto a liquid surface, finding a high-speed horizontal jet which emerges immediately following the intial contact. For ${\hbox{\it Re}} > 2 \times 10^4$ the jet emerges when the horizontal contact between the sphere and the liquid is only 12% of its diameter. For the largest Reynolds numbers this jet can travel at more than 30 times the impact velocity of the sphere. This jetting occurs sooner and at much higher normalized velocities than has been observed previously. The breakup of the jet into a spray of droplets sometimes occurs through formation of pockets in the liquid sheet. Early in the impact, the energy transferred to the jet and the subsequent spray sheet is estimated to be much larger than the energy associated with the added mass inside the liquid pool. The jetting will therefore greatly increase the initial impact force on the sphere.
In order to characterize the heat generation behavior of a lithium-ion cell during charge and discharge, calorimetry has been carried out. The influence of past treatments applied to the cell is examined based on heat generation. The test cell shows a voltage hysteresis during charge and discharge, and the heat generation behavior is related to this hysteresis. A hard carbon is used in the cell as the negative electrode material, and the hysteresis mechanism and heat generation are discussed based on the reactions in the hard carbon electrode.
We have demonstrated the influence of surface microroughness on the electrical characteristics of MOS devices and investigated the influence of wafer's manufacturing methods, such as Czochralski(Cz), floating-zone(FZ), and epitaxial(Epi) silicon wafers, on the susceptibility to the surface microroughness when some chemical treatment was performed. As a result, it was found that Cz and FZ wafers are very susceptible to the surface microroughness and the amount of the vacancy of Epi wafer is much smaller than that of another wafers. It was also demonstrated that the electrical characteristics of very thin gate oxide films are strongly influenced by the silicon substrate quality. Epi wafer is a strong candidate for fablication of highly-reliable devices on 300mm wafers.
Numerical simulation of point defect distributions in a growing Czochralski silicon crystal with an abrupt change in the crystal growth rate from 1.0 to 0.4 mm/min was performed. The result was fitted to the experimental data for the flow pattern defects obtained from a crystal grown under simulated conditions. From the simulation result, it was observed that the axial temperature distribution shifts slightly upwards as a result of the growth rate reduction. Based upon the argument that the flow pattern defects are of vacancy-type, it is proposed that the generation rate of the flow pattern defects during crystal growth can be described by the classical nucleation rate theory proposed by Becker [Proc.Phys.Soc., 52, 71(1940)]. In addition, it is suggested that the vacancy concentration in the flow pattern defects depends upon the reaction time between the silicon interstitials and the flow pattern defects and thus the crystal growth rate.