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1.
Ariel Cohen 《Morphology》2016,26(1):91-103
-Er nominals usually obey the External Argument Generalization: the argument of the nominal receives the thematic role that the verb assigns to its external argument. I argue that this syntactic generalization, as well as the exceptions to it, can be explained by semantics.Specifically, -er nominals usually express properties that are inherent in the subject; I argue that they therefore belong to the class of expressions that express such properties—dynamic modals. Crucially, dynamic modals are subject oriented; hence, the proposal that -er nominals are dynamic modals naturally provides an account of the External Argument Generalization.  相似文献   

2.
Type and reference strains of members of the onygenalean family Arthrodermataceae have been sequenced for rDNA ITS and partial LSU, the ribosomal 60S protein, and fragments of β-tubulin and translation elongation factor 3. The resulting phylogenetic trees showed a large degree of correspondence, and topologies matched those of earlier published phylogenies demonstrating that the phylogenetic representation of dermatophytes and dermatophyte-like fungi has reached an acceptable level of stability. All trees showed Trichophyton to be polyphyletic. In the present paper, Trichophyton is restricted to mainly the derived clade, resulting in classification of nearly all anthropophilic dermatophytes in Trichophyton and Epidermophyton, along with some zoophilic species that regularly infect humans. Microsporum is restricted to some species around M. canis, while the geophilic species and zoophilic species that are more remote from the human sphere are divided over Arthroderma, Lophophyton and Nannizzia. A new genus Guarromyces is proposed for Keratinomyces ceretanicus. Thirteen new combinations are proposed; in an overview of all described species it is noted that the largest number of novelties was introduced during the decades 1920–1940, when morphological characters were used in addition to clinical features. Species are neo- or epi-typified where necessary, which was the case in Arthroderma curreyi, Epidermophyton floccosum, Lophophyton gallinae, Trichophyton equinum, T. mentagrophytes, T. quinckeanum, T. schoenleinii, T. soudanense, and T. verrucosum. In the newly proposed taxonomy, Trichophyton contains 16 species, Epidermophyton one species, Nannizzia 9 species, Microsporum 3 species, Lophophyton 1 species, Arthroderma 21 species and Ctenomyces 1 species, but more detailed studies remain needed to establish species borderlines. Each species now has a single valid name. Two new genera are introduced: Guarromyces and Paraphyton. The number of genera has increased, but species that are relevant to routine diagnostics now belong to smaller groups, which enhances their identification.  相似文献   

3.
An aerobic hyperthermophilic CO-oxidizing archaeon, Sulfolobus sp. strain ETSY, was isolated and characterized. Presently, it is the only known representative of both hyperthermophiles and Archaea that is capable of aerobic oxidation of CO, a gas of global importance for atmospheric chemistry and of local importance as one of the substrates for the microbial communities of hydrothermal vents. In the genome of Sulfolobus sp. ETSY we found genetic determinants of aerobic CO oxidation: a coxFMSLDE gene cluster and two separately located coxG genes. We also found such gene clusters in the genomes of certain strains of Sulfolobus islandicus and Sulfolobus solfataricus. On the phylogenetic tree of large subunits of aerobic CO-dehydrogenases (CoxLs), these proteins of Sulfolobus representatives formed a compact cluster within one of the branches formed by bacterial form I CoxLs. Thus we argue that the ability to oxidize CO aerobically was acquired by Sulfolobus ancestor from Bacteria relatively late in the evolution, presumably after the formation of the atmosphere with a high oxygen content.  相似文献   

4.
In this paper, we study the distribution of the feminine singular suffixes -et and -a in the present tense of Hebrew verb paradigms. The question we ask is which of these two suffixes is the default allomorph. The answer is not trivial. In terms of distribution, -a appears with limited environments and -et is clearly the elsewhere case, and thus the default. In terms of order, however, -et is the feminine singular suffix associated with the present tense, while -a emerges only when -et is blocked. We thus argue for multiple defaults, distinguishing between local and global default; -et is the local default, uniquely associated with feminine singular verbs in the present tense, while -a is the global default, associated with feminine singular but not specified for the present tense. We provide a formal analysis for the distribution of these suffixes within the framework of Optimality Theory, which allows the interaction of phonological constraints with constraints on morpho-syntactic feature mapping. We further study the partially unpredictable distribution of -et and -a in vowel final verbs, and present the results of an experiment where speakers employed unique strategies in order to assign the local default -et.  相似文献   

5.

Background

Klebsiella variicola was very recently described as a new bacterial species and is very closely related to Klebsiella pneumoniae; in fact, K. variicola isolates were first identified as K. pneumoniae. Therefore, it might be the case that some isolates, which were initially classified as K. pneumoniae, are actually K. variicola. The aim of this study was to devise a multiplex-PCR probe that can differentiate isolates from these sister species.

Result

This work describes the development of a multiplex-PCR method to identify K. variicola. This development was based on sequencing a K. variicola clinical isolate (801) and comparing it to other K. variicola and K. pneumoniae genomes. The phylogenetic analysis showed that K. variicola isolates form a monophyletic group that is well differentiated from K. pneumoniae. Notably, the isolate K. pneumoniae 342 and K. pneumoniae KP5-1 might have been misclassified because in our analysis, both clustered with K. variicola isolates rather than with K. pneumoniae. The multiplex-PCR (M-PCR-1 to 3) probe system could identify K. variicola with high accuracy using the shared unique genes of K. variicola and K. pneumoniae genomes, respectively. M-PCR-1 was used to assay a collection of multidrug-resistant (503) and antimicrobial-sensitive (557) K. pneumoniae clinical isolates. We found K. variicola with a prevalence of 2.1% (23/1,060), of them a 56.5% (13/23) of the isolates were multidrug resistant, and 43.5% (10/23) of the isolates were antimicrobial sensitive. The phylogenetic analysis of rpoB of K. variicola-positive isolates identified by multiplex-PCR support the correct identification and differentiation of K. variicola from K. pneumoniae clinical isolates.

Conclusions

This multiplex-PCR provides the means to reliably identify and genotype K. variicola. This tool could be very helpful for clinical, epidemiological, and population genetics studies of this species. A low but significant prevalence of K. variicola isolates was found, implying that misclassification had occurred previously. We believe that our multiplex-PCR assay could be of paramount importance to understand the population dynamics of K. variicola in both clinical and environmental settings.
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6.
Two new books—Creating Language: Integrating Evolution, Acquisition, and Processing by Morten H. Christiansen and Nick Chater, and Why Only Us: Language and Evolution by Robert C. Berwick and Noam Chomsky—present a good opportunity to assess the state of the debate about whether or not language was made possible by language-specific adaptations for syntax. Berwick and Chomsky argue yes: language was made possible by a single change to the computation Merge. Christiansen and Chater argue no: our syntactic abilities developed on the back of natural selection for general-purpose sequence learning mechanisms. While Christiansen and Chater’s book testifies to impressive developments in constructivist approaches to language development, it’s not obvious that it has the resources to explain the hierarchical nature of syntactic binding. Despite this, the views have much in common.  相似文献   

7.
The authors submit a taxonomic evaluation of an intermediate group of strains between the speciesSaccharomyces carlsbergensis Hansen andSaccharomyces cerevisiae Hansen. The material consisted of atypical strains of “bottom” brewer’s yeasts and the synonymous strainsSaccharomyces monacensis Hansen andSaccharomyces mandshuricus Saito. It was found that there were two different serological types in the speciesSaccharomyces carlsbergensis, one of which was characterized by the presence of antigen “C” and was typical for this species, while the other possessed antigen “M” and was grouped roundSaccharomyces monacensis. This second serological type merges with a group of strains which gives only one third fermentation of raffinose, so that it is actually an intermediate betweenSaccharomyces cerevisiae Hansen andSaccharomyces carlsbergensis Hansen and indicates the course of progressive development from the former species to the latter. No close similarity was found betweenSaccharomyces mandshuricus Saito and some of the strains of the transitional group or typical representatives of the two main species, and the authors therefore consider that there is some obscurity as to its synonymity withSaccharomyces carlsbergensis.  相似文献   

8.
Toxic heavy metal contamination in Chinese edible herbs has raised a worldwide concern. In this study, heavy metals in Epimedii Folium, an edible medicinal plant in China, were quantitatively analyzed. Variations of heavy metals in different species, in various organs (i.e., leaves, stems, and roots), in wild-growing and cultivated plants, and in 35 market samples of Epimedii Folium, were systematically investigated. In all of Epimedium samples, Hg (mercury) was not detectable (0.00 μg/g). Four species, Epimedium pubescens, Epimedium sagittatum, Epimedium brevicornu, and Epimedium wushanense, were found to contain Cu (copper) and Pb (lead). And contents of Cu and Pb in E. brevicornu were significantly higher than those in other species (P < 0.01). In wild-growing and cultivated Epimedium plants, Cd (cadmium) and As (arsenic) were not detectable, and concentrations of Cu and Pb in wild-growing plants were significantly higher than those in cultivated plants (P < 0.01). Cd was not detectable in leaves, roots, and stems, while organ specificity was apparent in the distribution of Cu, As, and Pb. And the highest levels of Cu and Pb were observed in roots and leaves, respectively. In Chinese markets, several samples of Epimedii Folium contained excessive Cu, Cd, As, and Pb beyond the national permissible limits. In summary, there was a large variation of heavy metals among Epimedii Folium samples, and Cu and Pb were the most important heavy metals contaminating the edible medicinal plant. Application of Epimedii Folium to drug and food industries will need to focus more on toxic heavy metal contamination.  相似文献   

9.
10.
Natural polymorphisms at the foraging (for) gene influence several behaviors. However, it is seldom clear how different for alleles could be selected. In one case, Drosophila with the rover allele (for r ) have higher locomotor activity in the presence of food than animals with the sitter allele (for s ), suggesting a complementary feeding strategy. There are, in addition, differences between for r and for s Drosophila in some tests of short-term memory (for r animals generally perform at higher levels) and thermotolerance (for s larvae are more resistant to the effects of high-temperature). We asked whether there could be a direct compensating advantages in adult for s flies that could maintain the natural for variants. First, are adult for s flies more thermotolerant? Second, do for r flies have a higher short-term place memory? Third, as an alternative, might for s flies have higher place memory? Our results do not confirm these possibilities. Thus, a thermotolerance advantage of for s flies does not compensate for a potential for r short-term memory advantage; for r flies do not have a universal advantage in short-term memory; and for s flies do not have an advantage in place memory that could compensate for for r advantages in other learning contexts.  相似文献   

11.
We describe a new cliff-dwelling species within Sonchus (Asteraceae): Sonchus boulosii and analyze its systematic position and evolutionary significance; in addition, we provide a key to the species of Sonchus in Morocco. Both morphological and ecological characteristics suggest a close relationship of S. boulosii with taxa of section Pustulati. However, ITS nrDNA and cpDNA matK markers indicate its uncertain position within the genus, but clear genetic differentiation from the remaining major clades. ITS phylogenetic trees show that likely evolutionary shifts to rocky habitat took place at least five times within genus Sonchus and that sect. Pustulati and S. boulosii clades have a clearly independent evolutionary origin. We postulate that the strong resemblance of S. boulosii to other rocky species reflects a phenomenon of homoplasy, probably driven by parallel evolutionary adaptations to the severe ecological constraints of its cliff face habitat. Therefore, a new section is also described, which includes S. boulosii as its sole representative: section Pulvinati. According to phylogenetic trees, the new clade may share its common ancestor with the clade comprising sections Maritimi and Arvenses, from which it is widely divergent in morphology and ecology, with the exception of Sonchus novae-zelandiae. However, the latter is a derived taxon, with high level of polyploidy unlike S. boulosii that shows 2n?=?18, basal chromosome number of the genus. Since sections Pulvinati and Pustulati seem to be quite old in Sonchus, we also hypothesize that some similarities, such as fruit morphology, may reflect the persistence of some primitive characteristics.  相似文献   

12.

Background

Reconstructing the genome of a species from short fragments is one of the oldest bioinformatics problems. Metagenomic assembly is a variant of the problem asking to reconstruct the circular genomes of all bacterial species present in a sequencing sample. This problem can be naturally formulated as finding a collection of circular walks of a directed graph G that together cover all nodes, or edges, of G.

Approach

We address this problem with the “safe and complete” framework of Tomescu and Medvedev (Research in computational Molecular biology—20th annual conference, RECOMB 9649:152–163, 2016). An algorithm is called safe if it returns only those walks (also called safe) that appear as subwalk in all metagenomic assembly solutions for G. A safe algorithm is called complete if it returns all safe walks of G.

Results

We give graph-theoretic characterizations of the safe walks of G, and a safe and complete algorithm finding all safe walks of G. In the node-covering case, our algorithm runs in time \(O(m^2 + n^3)\), and in the edge-covering case it runs in time \(O(m^2n)\); n and m denote the number of nodes and edges, respectively, of G. This algorithm constitutes the first theoretical tight upper bound on what can be safely assembled from metagenomic reads using this problem formulation.
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13.
Gundruk is a fermented leafy vegetable and khalpi is a fermented cucumber product, prepared and consumed in the Himalayas. In situ fermentation dynamics during production of gundruk and khalpi was studied. Significant increase in population of lactic acid bacteria (LAB) was found during first few days of gundruk and khlapi fermentation, respectively. Gundruk fermentation was initiated by Lactobacillus brevis, Pediococcus pentosaceus and finally dominated by Lb. plantarum. Similarly in khalpi fermentation, heterofermentative LAB such as Leuconostoc fallax, Lb. brevis and P. pentosaceus initiated the fermentation and finally completed by Lb. plantarum. Attempts were made to produce gundruk and khalpi using mixed starter culture of LAB previously isolated from respective products. Both the products prepared under lab condition had scored higher sensory-rankings comparable to market products.  相似文献   

14.
Ambrosia beetles subsist on fungal symbionts that they carry to, and cultivate in, their natal galleries. These symbionts are usually saprobes, but some are phytopathogens. Very few ambrosial symbioses have been studied closely, and little is known about roles that phytopathogenic symbionts play in the life cycles of these beetles. One of the latter symbionts, Raffaelea lauricola, causes laurel wilt of avocado, Persea americana, but its original ambrosia beetle partner, Xyleborus glabratus, plays an uncertain role in this pathosystem. We examined the response of a putative, alternative vector of R. lauricola, Xyleborus bispinatus, to artificial diets of R. lauricola and other ambrosia fungi. Newly eclosed, unfertilized females of X. bispinatus were reared in no-choice assays on one of five different symbionts or no symbiont. Xyleborus bispinatus developed successfully on R. lauricola, R. arxii, R. subalba and R. subfusca, all of which had been previously recovered from field-collected females of X. bispinatus. However, no development was observed in the absence of a symbiont or on another symbiont, Ambrosiella roeperi, recovered from another ambrosia beetle, Xylosandrus crassiusculus. In the no-choice assays, mycangia of foundress females of X. bispinatus harbored significant colony-forming units of, and natal galleries that they produced were colonized with, the respective Raffaelea symbionts; with each of these fungi, reproduction, fecundity and survival of the beetle were positively impacted. However, no fungus was recovered from, and reproduction did not occur on, the A. roeperi and no symbiont diets. These results highlight the flexible nature of the ambrosial symbiosis, which for X. bispinatus includes a fungus with which it has no evolutionary history. Although the “primary” symbiont of the neotropical X. bispinatus is unclear, it is not the Asian R. lauricola.  相似文献   

15.
A method for in vivo studying the fidelity of DNA double-strand break (DSB) repair in bacteriophage T4 has been developed. The frequency of reversion of rII mutations to the wild phenotype was measured in i segC + × i ets1 segCΔ crosses, where ets1 is an insertion in the initial part of the rIB gene carrying a sequence recognized by SegC endonuclease; i designates a rIIB or rIIA mutation located at some distance from ets1, and segCΔ is a deletion in the segC gene. In such cross, a DSB occurs in the site of ets1. Their repair involves genetic recombination and DNA replication in the neighborhood of ets1. In parallel, the frequency of reversion of the same i mutant in the absence of DSBs is measured in i × i self-crosses. Reversions of different types (base substitutions, deletions, insertions) can be studied with the use of structurally different i mutations located at varying distances from ets1. The reversion frequencies were determined for three rIIB mutations and one rIIA mutation. The results obtained suggest that DSB repair in bacteriophage T4 is a process of high fidelity with the rate of errors that does not essentially exceed that in the case of usual phage multiplication.  相似文献   

16.
Rat bite fever is an under-reported, under-diagnosed emerging zoonosis with worldwide distribution. Besides Spirillum minus, Streptobacillus moniliformis is the major causative microorganism although it usually colonises rats without any clinical signs. A group of house rats (Rattus rattus) kept in a zoo exhibition for educational purposes suffered from neurological signs including disorientation, torticollis, stall walking, ataxia and death. Gross pathological and histo-pathological examinations of the investigated rats revealed high-grade otitis interna et media, from which Streptobacillus notomytis was isolated in pure culture or as the predominant microorganism. This case series underlines a previously expressed hypothesis that R. rattus might be naturally colonised with S. notomytis, whereas the traditional rat bite fever organism, S. moniliformis, might be restricted to the Norway rat (Rattus norvegicus). However, the general paucity of Streptobacillus isolates, especially from their respective animal hosts, precludes definitive proof of these host tropisms. This is the first report of S. notomytis detection outside Asia and Australia and the first evidence for its role as a facultative pathogen in house rats.  相似文献   

17.
Rabbit neutrophils peptide-1 (NP-1) is a type of defensin that possesses a broad spectrum of antimicrobial activity. Chlorella ellipsoidea is a new eukaryotic expression system for exogenously producing NP-1. The NP-1 transgenic C. ellipsoidea can be directly added into feed as antimicrobial agent without any purification procedure for the NP-1 peptide. However, the effects of C. ellipsoidea and NP-1 on the host gut microbiota should be explored before application. In this study, diets containing different concentrations (1.25, 2.5, and 5 %) of C. ellipsoidea and NP-1 transgenic C. ellipsoidea were administered to male Sprague–Dawley rats. Compared with the chow diet control group, none of the experimental groups showed any significant differences in their growth indices, and no histopathological damage was observed. The phylotypes of gut microbiota in the control group, the 5 % C. ellipsoidea diet group and the 5 % NP-1 transgenic C. ellipsoidea diet group were determined by 16S rRNA sequencing. The results showed that both 5 % experimental groups had shifted community memberships of gut microbiota. In particular, the 5 % NP-1 transgenic C. ellipsoidea diet exhibited an increased abundance of most Gram-positive bacterial taxa and a reduced abundance of most Gram-negative bacterial taxa, and it promoted the growth of some lactic acid bacterial genera. Lactic acid bacteria, especially the Bifidobacterium and Lactobacillus, have been widely reported to be benefic effects on the host. Thus NP-1 transgenic C. ellipsoidea is promising feed additive and gut regulator, as it have the potential to increase the abundance of Bifidobacterium and Lactobacillus in gut microbiota of animal.  相似文献   

18.
The predator Adalia bipunctata (Coleoptera: Coccinellidae) and the entomopathogenic fungus Lecanicillium muscarium, have been considered as potential biological control against aphids. While it can be difficult to achieve a high control level of Aphis fabae Scopoli (Hemiptera: Aphididae) using only a single beneficial agent, the research presented here aimed to determine the interaction between L. muscarium and A. bipunctata potential for control against A. fabae. Lecanicillium muscarium was found to cause about 30% mortality in A. bipunctata and with a reduction in feeding by about 15%. However, co-application of A. bipunctata and L. muscarium can cause an addititive effect in reducing aphid populations, resulting in about 90% reduction in aphid populations compared with control treatment. Thus, these two biocontrol agents have the potential to be complementary. This research study demonstrates that it is possible to combine A. bipunctata with L. muscarium to provide a sustainable method for management of A. fabae on broad bean cropping system and that field studies are required.  相似文献   

19.
Phosphorous (P) availability is a major concern in European agriculture where reserves are limited. In the case of pea (Pisum sativum L.), one of the most important legumes in the human diet, P has specific effects on nodulation and N2 fixation. Therefore, when biofertilization schemes are considered for pea cropping, it is very important to include symbiotic dinitrogen-fixing bacteria as well as phosphate-solubilizing bacteria (PSB). In this study sixteen PSB were isolated from the rhizosphere of two pea cultivars in two French soils with different characteristics. They were phenotypically and genotypically diverse displaying 9 different Two Primers-Random Amplified Polymorphic DNA (TP-RAPD) patterns. The 16S rRNA gene analysis of representative strains showed that they belong to four highly divergent phylogenetic groups. Most of the PSB strains belonged to the genus Pseudomonas and were closely related to Pseudomonas baetica, P. lutea, P. azotoformans, P. jessenii and P. frederiksbergensis. Other strains from the genus Burkholderia were closely related to B. caledonica and those from the genus Rhizobium to R. grahamii. The single strain of genus Bacillus was close to Bacillus toyonensis. Some phylogenetic groups to which our PSB strains belong are widely distributed in plant rhizospheres in different countries and continents. This is particularly interesting in the case of strains from the phylogenetic group of P. fluorescens which includes PSB strains with high ability to solubilize phosphate indicating that they may be used as biofertilizers in many soils.  相似文献   

20.
Boletus edulis Bull. is one of the most economically and gastronomically valuable fungi worldwide. Sporocarp production normally occurs when symbiotically associated with a number of tree species in stands over 40 years old, but it has also been reported in 3-year-old Cistus ladanifer L. shrubs. Efforts toward the domestication of B. edulis have thus focused on successfully generating C. ladanifer seedlings associated with B. edulis under controlled conditions. Microorganisms have an important role mediating mycorrhizal symbiosis, such as some bacteria species which enhance mycorrhiza formation (mycorrhiza helper bacteria). Thus, in this study, we explored the effect that mycorrhiza helper bacteria have on the efficiency and intensity of the ectomycorrhizal symbiosis between C. ladanifer and B. edulis. The aim of this work was to optimize an in vitro protocol for the mycorrhizal synthesis of B. edulis with C. ladanifer by testing the effects of fungal culture time and coinoculation with the helper bacteria Pseudomonas fluorescens Migula. The results confirmed successful mycorrhizal synthesis between C. ladanifer and B. edulis. Coinoculation of B. edulis with P. fluorescens doubled within-plant mycorrhization levels although it did not result in an increased number of seedlings colonized with B. edulis mycorrhizae. B. edulis mycelium culture time also increased mycorrhization levels but not the presence of mycorrhizae. These findings bring us closer to controlled B. edulis sporocarp production in plantations.  相似文献   

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