Horizontal gene transfer （HGT） plays key roles in the evolution of pathogenetic bacteria, especially in pathogenetic associated genes. In this study, the evolutionary dynamics of Xanthomonas at ...species level were determined by the comparative analysis of the complete genomes of 15 Xanthomonas strains. A concatenated multiprotein phyletic pattern and a dataset with Xanthomonas clusters of orthologous genes were constructed. Mathematical extrapolation estimates that the core genome will reach a minimum of about 1 547 genes while the pan-genome will increase up to 22 624 genes when sequencing 1 000 genomes. The HGT extent in this genus was assessed by using a Markov-based probabilistic method. The reconstructed gene gain/loss history, which contained several features consistent with biological observations, showed that nearly 60% of the Xanthomonas genes were acquired by HGT. A large fraction of variability was in the clade ancestor nodes and ＂leaves of the tree＂. Coexpression analysis suggested that the pathogenic and metabolic variation between Xanthomonas oryzae pv. oryzicola and Xanthomonas oryzae pv. oryzae might due to recently-transferred genes. Our results strongly supported that the gene gain/loss may play an important role in divergence and pathogenicity variation of Xanthomonas species.
BACKGROUND Leptinotarsa decemlineata is an able disperser by flight. Novel control strategies must be explored to control the damage and inhibit the dispersal efficiently. Proline is a major energy ...substrate during flight. Delta -Pyrroline-5-carboxylate dehydrogenase (P5CDh) catalyses the second step of proline degradation for the production of ATP. RESULTS A full-length Ldp5cdh cDNA was cloned. Ldp5cdh was ubiquitously expressed in the eggs, the first through fourth larval instars, wandering larvae, pupae and adults. In the adults, Ldp5cdh mRNA was widely distributed in thorax muscles, midgut, foregut, hindgut, Malpighian tubules, ventral ganglion, fat body and epidermis, with the expression levels from the highest to the lowest. Two double-stranded RNAs (dsRNAs) (ds Ldp5cdh 1 and ds Ldp5cdh2 ) targeting Ldp5cdh were constructed and bacterially expressed. Ingestion of ds Ldp5cdh 1 and ds Ldp5cdh2 successfully silenced Ldp5cdh , significantly increased the contents of proline, arginine and alanine, but strongly decreased the contents of asparate, asparagine, glutamate and glutamine in the haemolymph. Moreover, knocking down Ldp5cdh significantly reduced ATP content, decreased flight speed, shortened flight distance and increased adult mortality. CONCLUSIONS It seems that identified Ldp5cdh encodes a functional P5CDh enzyme, and Ldp5cdh may serve as a potential target for dsRNA-based pesticide for controlling the damage and dispersal of L. decemlineata adults.
INTRODUCTION
Congenital vascular rings （VRs） are a group of rare cardiovascular anomalies that result from abnormal embryonic development of the paired aortic arches or branching pulmonary arteries. ...Clinical presentation of VR depends on its anatomy, degree, and site of compression.
Summary
C
oniothyrium minitans
(
Cm
) is a mycoparasite of the phytopathogenic fungus
S
clerotinia sclerotiorum
(
Ss
).
Ss
produces a virulence factor oxalic acid (
OA
) which is toxic to plants and ...also to
Cm
, and
Cm
detoxifies
OA
by degradation. In this study, two oxalate decarboxylase genes,
Cmoxdc1
and
Cmoxdc2
, were cloned from
Cm
strain Chy‐1.
OA
and low
pH
induced expression of
Cmoxdc1
, but not
Cmoxdc2
.
Cmoxdc1
was partially responsible for
OA
degradation, whereas
Cmoxdc2
had no effect on
OA
degradation. Disruption of
Cmoxdc1
in
Cm
reduced its ability to infect
Ss
in dual cultures where
OA
accumulated. Compared with
Chy
‐1, the
Cmoxdc1
‐disrupted mutants had reduced expression levels of two mycoparasitism‐related genes chitinase (
Cmch1
) and β‐1,3‐glucanase (
Cmg1
), and had no detectable activity of extracellular proteases in the presence of
OA
. On the other hand, the cultural filtrates of the
Cmoxdc1
‐disrupted mutants in
OA
‐amended media showed enhanced antifungal activity, possibly because of increased production of antifungal substances under acidic
pH
condition resulted from reduced
Cmoxdc1
‐
mediated
OA
degradation. This study provides direct genetic evidence of
OA
degradation regulating mycoparasitism and antibiosis of
Cm
against
Ss
, and sheds light on the sophisticated strategies of
Cm
in interacting with metabolically active mycelia and dormant sclerotia of
Ss
.
A self-adaptive improved particle swarm optimization (IPSO) algorithm applied to available transfer capability (ATC) calculation is presented in this paper. Firstly, a new self-adaptive adjustment ...inertia-weighted strategy factor, which elevates the adaptability of particle swarm optimization (PSO) and accelerates convergence-speed of PSO, is proposed. Secondly, studying the search characteristics of PSO, penalty function is assigned dynamically. By this enhanced study behavior, the opportunity to find the global optimum is increased and the influence of the initial position of the particles is decreased. Thirdly, IPSO algorithm is adopted to solve the problem of ATC calculation. At last, the numeric simulation for IEEE 30-bus system demonstrates that this new IPSO is feasible and effective to solve the problem of ATC calculation.
More and more cities develop rail transit to solve transit difficulties. While the high building and operational cost set back the development. A new multi-function integrated ventilation and air ...conditioning system has been researched and developed for city rail transit to solve this problem. Combined with the line 5 metro system of Beijing, system function, composition, operation mode has been analyzed in detail. System scheme were simulated in computer and tested with machine. The scheme effect was tested. The scheme was combined with traditional scheme in technical, economy and operational cost.
In order to investigate the water security situation in typical rural areas of Shandong province, the index system of water security assessment were estasblished based on full understanding of water ...security as well as combination between actual situation of Shandong province and the definition rural water security. With six county-level city of Shandong province as examples for water security evaluation, each index weigh was calculated by entropy method according to the fuzzy comprehensive evaluation method .It was showed that the water security rank from bad to good was shouguang city, ju county, qingyun county, wendeng city, feicheng city and linqu county. The evaluation results was in keeping with the actual condition of water resources, which shows that this system is applicable on rural water security evaluation.
With the development of spatial techniques in geographic information systems (GIS), new methods have allowed for robust and detailed preparation of digital models of the earth's surface elevation, ...interpolation of climate parameters, and remote sensing of surface conditions in terrestrial environments. These methods in turn have led to greatly enhanced species distribution models (also called species niche models) by providing estimates of environmental conditions and predictions of potential and actual species distribution areas across entire landscapes. Species distribution models have become the subject of active field of research in large-scale ecology and biogeography, and have been used to solve many ecological issues in recent decades. Models are used for biodiversity assessment; biological reserve design; habitat management and restoration; population viability analysis; environmental risk assessment; invasive species management; community and ecosystem modeling; and predicting the effects of global environmental change on species and ecosystems. Species distribution models using species occurrence records (presence only or presence/absence data) associated with environmental variables seek to determine the fundamental niche or realized niche of a particular species, and then to project this niche onto the landscape of interest to reflect the potential distribution area of the species. Results could be interpreted as the probability of occurrence of the species, species habitat suitability or species relative richness. However, there is still insufficient knowledge of the theoretical basis of species distribution models, as some of the key ecological processes have not been incorporated into the framework of these models. This generates substantial confusion when the predicted results of species distribution models are explained. For more efficient use and further development of species distribution models, this study provides: 1) a full overview of the history and recent theoretical advances in the field of species distribution models; 2) a systematic discussion of the relationship between species distribution model and species distribution area; 3) a highlight of the critical limitations inherent in species distribution models; and 4) a focus on challenges of species distribution models for future research. Results from this study suggest that the theoretical basis of species distribution models is strongly related to niche theory, source-sink theory, population dynamics theory, metapopulation theory, and evolutionary theory. Proper understanding of the relationship between the predicted and actual species distribution area depends on separation of three factors (environmental condition, species interactions and species migration ability) affecting the distribution area of species. The main problems of current species distribution models are that they fail to efficiently integrate species interaction and species migration ability into the model building process, which creates gaps between the predicted and actual species distribution area under normal circumstances. Future development of species distribution models should focus on strengthening their inherent theoretical framework, and must integrate species interactions process, population dynamics process, migration process and evolutionary process into models. This study also suggests that simulating functional groups and community structure from higher theoretical levels is important for the development of species distribution models. We believe that through the efforts of scientists, future species distribution models can overcome the above-mentioned drawbacks and can dynamically model the multi-species potential distribution area, thus providing a more in-depth theoretical study of community ecology and biogeography.
PDF
