A large number of insect-specific viruses (ISVs) have recently been discovered, mostly from hematophagous insect vectors because of their medical importance, but little attention has been paid to important plant virus vectors such as the whitefly Bemisia tabaci, which exists as a complex of cryptic species. Public SRA datasets of B. tabaci and newly generated transcriptomes of three Chinese populations are here comprehensively investigated to characterize the whitefly viromes of different cryptic species. Twenty novel ISVs were confidently identified, mostly associated with a particular cryptic species while different cryptic species harbored one or more core ISVs. Microinjection experiments showed that some ISVs might cross-infect between the two invasive whitefly cryptic species, Middle East Asia Minor 1 (MEAM1) and Mediterranean (MED), but others appeared to have a more restricted host range, reflecting the possibility of distinct long-term coevolution of these ISVs and whitefly hosts. Moreover, analysis of the profiles of virus-derived small-interfering RNAs indicated that some of the ISVs can successfully replicate in whitefly and the antiviral RNAi pathway of B. tabaci is actively involved in response to ISV infections. Our study provides a comprehensive analysis of the RNA virome, the distinct relationships and cross-cryptic species infectivity of ISVs in an agriculturally important insect vector.
There exists a kind of symbiotic bacterium named "Candidatus Arsenophonus nilaparvatae" in the brown planthopper (BPH), Nilaparvata lugens. After being filtered and assembled from the BPH genome sequencing project, the genome sequence of this bacterial symbiont was obtained. After initial analysis based on the genome, we have found its potential role to synthesize B vitamins for the host. In order to better understand the lifestyle and the genomic changes of this symbiotic bacterium after the symbiotic relationship was established, we further report the characteristics of this draft genome. Compared with several other related bacteria, "Candidatus Arsenophonus nilaparvatae" has proven to be a facultative endosymbiont at the genomic level. Concurrently, the presence of fimbriae and flagella formation related genes indicates this maternally transmitted endosymbiont is most likely to retain the capacity to invade new hosts. Through further analysis of annotated gene sets, we also find evidence of genome reduction in its secretion system and metabolic pathways. These findings reflect its evolutionary trend to be an obligate one and enable a deeper study of microbe-insect interactions.
Acrylonitrile–butadiene–styrene (ABS) is one of the most important materials utilized by fused deposition modeling (FDM) 3D printing. In this work, we prepared a series of 3D-printable ABS-based materials with improved scratch resistance and balanced mechanical performance via a simple blending strategy. The scratch resistant performance, mechanical strength, melt flow rate, hardness, transmittance, and surface gloss of ABS were improved simultaneously by adding 30 mass portion of poly(methyl methacrylate) (PMMA). Further addition of a small amount of methacrylate–butadiene–styrene (MBS), a kind of core–shell rubber modifier with high toughening efficiency, improved the toughness of ABS/PMMA effectively and hardly influenced the scratch resistance and optical properties of ABS/PMMA. This ABS/PMMA/MBS blend has the potential for large-scaled fabrication and can be developed as a new category of thermoplastic polymer material specially used for FDM 3D printing.
Background. Abdominoperineal resection (APR) has been the standard surgery for ultra-low rectal cancer for a century. In recent years, intersphincteric resection (ISR) has been increasingly used to avoid the permanent colostomy. Up to now, there is no relevant meta-analysis comparing the clinical efficacy of ISR and APR. This meta-analysis aimed to compare the outcomes of these 2 procedures. Methods. A comprehensive search of online databases was performed on PubMed, EMBASE, and the Cochrane Library to obtain comparative studies of ISR and APR. Then the data from studies that met the inclusion criteria were extracted and analyzed. Results. A total of 12 studies covering 2438 patients were included. No significant differences were found between ISR and APR in gender, body mass index, distance from tumor to anal edge, operative time, and blood loss. In addition, hospital stay (weighted mean differences = −2.98 days; 95% confidence interval [CI] = −3.54 to −2.43; P < .00001) and postoperative morbidity (odds ratio [OR] = 0.76; 95% CI = 0.59 to 0.99; P = .04) were significantly lower in ISR group compared with APR group. However, patients who underwent ISR showed lower pathological T-stage (T3T4%, OR = 0.49; 95% CI = 0.28 to 0.86; P = .01) and lymph node metastasis rate (OR = 0.77; 95% CI = 0.59 to 1.01; P = .06) compared with those who underwent APR. Moreover, oncological outcomes were similar between the 2 groups. Conclusion. ISR may provide a safe alternative to APR, with shorter hospital stays, lower postoperative morbidity, and similar oncological outcomes. Well-designed randomized controlled trials are needed to confirm and update the findings of this analysis.
BackgroundSeminal fluid proteins (SFPs) are produced mainly in the accessory gland of male insects and transferred to females during mating, in which they induce numerous physiological and post-mating behavioral changes. The brown plant hopper (BPH), Nilaparvata lugens, is an economically important hemipterous pest of rice. The behavior and physiology of the female of this species is significantly altered by mating. SFPs in hemipteran species are still unclear.ResultsWe applied high-throughput mass spectrometry proteomic analyses to characterize the SFP composition in N. lugens. We identified 94 putative secreted SFPs, and the expression levels of these proteins was determined from the male accessory gland digital gene expression database. The 94 predicted SFPs showed high expression in the male accessory gland. Comparing N. lugens and other insect SFPs, the apparent expansion of N. lugens seminal fluid trypsins and carboxylesterases was observed. The number of N. lugens seminal fluid trypsins (20) was at least twice that in other insects. We detected 6 seminal fluid carboxylesterases in N. lugens seminal fluid, while seminal fluid carboxylesterases were rarely detected in other insects. Otherwise, new insect SFPs, including mesencephalic astrocyte–derived neurotrophic factor, selenoprotein, EGF (epidermal growth factor) domain–containing proteins and a neuropeptide ion transport-like peptide were identified.ConclusionThis work represents the first characterization of putative SFPs in a hemipeteran species. Our results provide a foundation for future studies to investigate the functions of SFPs in N. lugens and are an important addition to the available data for comparative studies of SFPs in insects.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3013-7) contains supplementary material, which is available to authorized users.
Amino acids are considered to be anabolic factors that affect protein turnover. The aim of this study was to test the effects of dietary L-arginine (Arg) levels on protein metabolism in the liver of laying hens and the expression of genes related to protein synthesis and proteolysis. Xinyang black commercial laying hens (n = 864, 31 wk of age) were randomly allotted to 6 treatments with 4 replicates of 36 birds. The dietary treatments were corn-corn gluten meal based diets containing 0.64, 0.86, 1.03, 1.27, 1.42, and 1.66% L-Arg, respectively. Serum concentrations of total protein and albumin were maximized in the 1.27% L-Arg group, and serum concentration of urea acid was the lowest in the 1.27% L-Arg group. The 1.27% L-Arg group had the highest fractional protein synthesis rate and fractional protein gain rate in the liver. Consistent with the data on protein turnover, mRNA abundances of target of rapamycin (TOR) and ribosomal protein S6 kinase 1 increased in the liver of layers fed 1.27% L-Arg, while mRNA abundances of cathepsin B and 20S proteasome decreased at the same dietary L-Arg level. In conclusion, the dietary level of L-Arg increased the liver fractional protein synthesis rate and fractional protein gain rate of laying hens, and the action of an appropriate level of dietary L-Arg involves upregulating the gene expression of the TOR signaling pathway accompanied by suppressing the mRNA expression of cathepsin B and 20S proteasome in the liver.
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