An Induced Hypersensitive-Like Response Limits Expression of Foreign Peptides via a Recombinant TMV-Based Vector in a Susceptible Tobacco

BACKGROUND: By using tobacco mosaic virus (TMV)-based vectors, foreign epitopes of the VP1 protein from food-and-month disease virus (FMDV) could be fused near to the C-terminus of the TMV coat protein (CP) and expressed at high levels in susceptible tobacco plants. Previously, we have shown that the recombinant TMV vaccines displaying FMDV VP1 epitopes could generate protection in guinea pigs and swine against the FMDV challenge. Recently, some recombinant TMV, such as TMVFN20 that contains an epitope FN20 from the FMDV VP1, were found to induce local necrotic lesions (LNL) on the inoculated leaves of a susceptible tobacco, Nicotiana tabacum Samsun nn. This hypersensitive-like response (HLR) blocked amplification of recombinant TMVFN20 in tobacco and limited the utility of recombinant TMV vaccines against FMDV. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigate the molecular mechanism of the HLR in the susceptible Samsun nn. Histochemical staining analyses show that these LNL are similar to those induced in a resistant tobacco Samsun NN inoculated with wild type (wt) TMV. The recombinant CP subunits are specifically related to the HLR. Interestingly, this HLR in Samsun nn (lacking the N/N'-gene) was able to be induced by the recombinant TMV at both 25°C and 33°C, whereas the hypersensitive response (HR) in the resistant tobacco plants induced by wt TMV through the N/N'-gene pathways only at a permissive temperature (below 30°C). Furthermore, we reported for the first time that some of defense response (DR)-related genes in tobacco were transcriptionally upregulated during HLR. CONCLUSIONS: Unlike HR, HLR is induced in the susceptible tobacco through N/N'-gene independent pathways. Induction of the HLR is associated with the expression of the recombinant CP subunits and upregulation of the DR-related genes

CO₂ Adsorption by Bamboo Biochars Obtained via a Salt-Assisted Pyrolysis Route

Recently, salt-assisted pyrolyzation has been deemed an emerging and efficient method for the preparation of biochars due to its facile operation as well as its good structural and chemical properties. In this work, biochars (MBCx) are prepared by heating bamboo powders in eutectic salts (Li2CO3 + K2CO3) at 500–600 °C in the air. Multiple technologies are employed to examine the physiochemical properties of bamboo biochars. Correlations between heating temperature and structural features and carbon dioxide uptakes of bamboo biochars have been investigated. The results show that heating temperature has a significant influence on the physicochemical properties of bamboo biochars. With the elevation of the heating temperature, the defect structures of bamboo biochars gradually ascend, especially when the heating temperature reaches 600 °C. MBCx biochars visibly exceed conventional bamboo biochar prepared via pyrolyzation in a nitrogen stream free of salt addition. Pyrolysis of bamboo in eutectic salts endows biochars with higher oxygen content and more carbon defects, which likely accounts for their better CO2 capture activities

Spatial Distribution Characteristics and Influencing Factors of Pro-Poor Tourism Villages in China

This paper aims to contribute to the effectiveness of pro-poor tourism in rural areas. We use 5770 pro-poor tourism villages in China as the research objects; the spatial distribution characteristics of pro-poor tourism villages in China are analyzed using a combination of disequilibrium index, kernel density analysis, and spatial autocorrelation; their influencing factors are detected using a geographical detector and overlay analysis. The study results show the following: (1) The distribution of pro-poor tourism villages is exceptionally uneven in three zones, eight regions, and inter-provincial levels, forming a high-density cluster belt that includes Hebei, Henan, Anhui, and Hubei, and five high-density cluster cores that include southern Gansu, Sichuan–Gansu–Shaanxi border area; Guizhou, Hunan, and Chongqing border area; southern Sichuan; and southwest Guizhou. (2) Regarding spatial correlations, the pro-poor tourism villages in central and western regions are in hot spots, while those in eastern regions are in cold spots. The hot spots gradually increase, while cold spots gradually decrease, and the clustering trend of the distribution of the pro-poor tourism villages is increasingly apparent. (3) Pro-poor tourism villages are affected by social, economic, industrial, and other human factors as well as natural geographical factors such as terrain, precipitation, river, and climate, among which the industrial factors have a more significant impact. Pro-poor tourism villages are concentrated in humid mountainous areas with an altitude of about 1000 m and an annual precipitation of more than 800 mm, and they are mostly distributed in the subtropical monsoon climate zone closer to the river and more suitable climate. (4) It is suggested that pro-poor tourism villages can be divided into four types: the resource underutilization type, mountain environment restriction type, traffic location non-optimization type, and industrial development lagging type, and the sustainable development strategies of different types of pro-poor tourism villages are proposed

LysZX4-NCA, a new endolysin with broad-spectrum antibacterial activity for topical treatment

The prevalence of multidrug-resistant highly virulent Klebsiella pneumoniae (MDR-hvKP) requires the development of new therapeutic agents. Herein, a novel lytic phage vB_KpnS_ZX4 against MDR-hvKP was discovered in hospital sewage. Phage vB_KpnS_ZX4 had a short latent period (5 min) and a large burst size (230 PFU/cell). It can rapidly reduce the number of bacteria in vitro and improve survival rates of bacteremic mice in vivo from 0 to 80 % with a single injection of 108 PFU. LysZX4, an endolysin derived from vB_KpnS_ZX4, exhibits potent antimicrobial activity in vitro in combination with ethylenediaminetetraacetic acid (EDTA). The antimicrobial activity of LysZX4 was further enhanced by the fusion of KWKLFKI residues from cecropin A (LysZX4-NCA). In vitro antibacterial experiments showed that LysZX4-NCA exerts broad-spectrum antibacterial activity against clinical Gram-negative bacteria, including MDR-hvKP. Moreover, in the mouse model of MDR-hvKP skin infection, treatment with LysZX4-NCA resulted in a three-log reduction in bacterial burden on the skin compared to the control group. Therefore, the novel phages vB_KpnS_ZX4 and LysZX4-NCA are effective reagents for the treatment of systemic and local MDR-hvKP infections

Spatial Distribution Characteristics and Influencing Factors of Pro-Poor Tourism Villages in China

This paper aims to contribute to the effectiveness of pro-poor tourism in rural areas. We use 5770 pro-poor tourism villages in China as the research objects; the spatial distribution characteristics of pro-poor tourism villages in China are analyzed using a combination of disequilibrium index, kernel density analysis, and spatial autocorrelation; their influencing factors are detected using a geographical detector and overlay analysis. The study results show the following: (1) The distribution of pro-poor tourism villages is exceptionally uneven in three zones, eight regions, and inter-provincial levels, forming a high-density cluster belt that includes Hebei, Henan, Anhui, and Hubei, and five high-density cluster cores that include southern Gansu, Sichuan–Gansu–Shaanxi border area; Guizhou, Hunan, and Chongqing border area; southern Sichuan; and southwest Guizhou. (2) Regarding spatial correlations, the pro-poor tourism villages in central and western regions are in hot spots, while those in eastern regions are in cold spots. The hot spots gradually increase, while cold spots gradually decrease, and the clustering trend of the distribution of the pro-poor tourism villages is increasingly apparent. (3) Pro-poor tourism villages are affected by social, economic, industrial, and other human factors as well as natural geographical factors such as terrain, precipitation, river, and climate, among which the industrial factors have a more significant impact. Pro-poor tourism villages are concentrated in humid mountainous areas with an altitude of about 1000 m and an annual precipitation of more than 800 mm, and they are mostly distributed in the subtropical monsoon climate zone closer to the river and more suitable climate. (4) It is suggested that pro-poor tourism villages can be divided into four types: the resource underutilization type, mountain environment restriction type, traffic location non-optimization type, and industrial development lagging type, and the sustainable development strategies of different types of pro-poor tourism villages are proposed

TMV recombinants encoding fused foreign transmembrane domains to the CP subunit caused local necrotic response on susceptible tobacco

AbstractWith regard to the effects of various foreign peptides fused to the coat protein subunits on the infectivity of corresponding TMV recombinants, some of TMV recombinants were found to induce necrotic local lesions on the inoculated leaves of susceptible tobacco. This paper reported that there existed a group of TMV recombinants in which the fused foreign peptides contained a transmembrane domain according to the predictions by three programs of SOSUI, TMpred and DAS. Further studies showed for the first time that a foreign transmembrane domain in a fused peptide of the corresponding TMV recombinant would result in the local lesions on the susceptible tobacco leaves. In addition, it was concluded that none of the TMV recombinants that systematically infected susceptible tobacco contained a transmembrane domain in the coat protein subunits

A Low-Complexity Acoustic Echo Canceller

This paper presents a novel acoustic echo canceller (AEC) consisting of an adaptive FIR filter and a double-talk detector (DTD). By employing the widely used LPC-based speech coder for decorrelation, we develop a variable step-size decorrelation NLMS algorithm for the adaptive filter and an echo-path mismatch detection algorithm for the double-talk detector. This new approach reduces the computational complexity of both adaptive algorithm and double-talk detection algorithm in order of magnitude. Simulation results show that the proposed algorithm has a superior performance compared with other existing relative algorithms.TelecommunicationsEICPCI-S(ISTP)

Preparation of SiO2 nanocomposites with aligned distributing glass fibre using freeze-drying process

The glass fibre reinforced nano-SiO2 composites (with up to 40 wt.% of glass fibres) as insulating materials were fabricated firstly by preparing aligned glass fibres under the ice formation followed by pressing and annealing. Scanning electron microscopy analyses confirmed the presence of parallel distribution of glass fibres in certain direction. The low-temperature nitrogen adsorption and mercury intrusion measurements showed that the composites have mesoporous structure with the mean pore size less than 20 nm. Further, it was found that the compressive strength and thermal conductivity of composite were 15.1 MPa and 0.0585 W/(m·K), respectively