A Pathogenesis-Related Protein-Like Gene Is Involved in the Panax notoginseng Defense Response to the Root Rot Pathogen

Pathogenesis-related proteins (PRs) are a class of proteins that accumulate in response to biotic and abiotic stresses to protect plants from damage. In this study, a gene encoding a PR-like protein (PnPR-like) was isolated from Panax notoginseng, which is used in traditional Chinese herbal medicines. An analysis of gene expression in P. notoginseng indicated that PnPR-like was responsive to an infection by the root rot pathogen Fusarium solani. The expression of this gene was induced by several signaling molecules, including methyl jasmonate, ethephon, hydrogen peroxide, and salicylic acid. The PnPR-like-GFP fusion gene was transiently expressed in onion (Allium cepa) epidermal cells, which revealed that PnPR-like is a cytoplasmic protein. The purified recombinant PnPR-like protein expressed in Escherichia coli had antifungal effects on F. solani and Colletotrichum gloeosporioides as well as inhibited the spore germination of F. solani. Additionally, the in vitro ribonuclease (RNase) activity of the recombinant PnPR-like protein was revealed. The PnPR-like gene was inserted into tobacco (Nicotiana tabacum) to verify its function. The gene was stably expressed in T₂ transgenic tobacco plants, which exhibited more RNase activity and greater disease resistance than the wild-type tobacco. Moreover, the transient expression of hairpin RNA targeting PnPR-like in P. notoginseng leaves increased the susceptibility to F. solani and decreased the PnPR-like expression level. In conclusion, the cytoplasmic protein PnPR-like, which has RNase activity, is involved in the P. notoginseng defense response to F. solani.

Precisely Controlling the Structure of Ultrathin Semiconducting Films by a Laminating Method for High-Performance Organic Field-Effect Transistors

High-performance organic field-effect transistors (OFETs) based on conjugated polymers have received extensive attention in recent years. However, the relationships between the multiscale structures of conjugated polymers and electrical properties are not well established. Here, laminated, ultrathin poly(3-hexylthiophene) (P3HT) films have been prepared using a sequential, repeated transfer-etching process from the precursor conjugated/insulating polymer blend films and used to study the structure-property relationship at the transition of the film structure from 2D to 3D. The molecular packing of the films is improved by lamination as certified by grazing incidence X-ray diffraction, UV-visible spectroscopy, and Raman spectroscopy. The laminated ultrathin P3HT films exhibit excellent electrical properties with a maximum mobility of 0.23 cm² V^-1 s^-1 at three layers, which is close to the highest value reported for undoped P3HT OFETs. Temperature-dependent FET characteristics reveal that the laminated films have low activation energy and a 2D charge transport profile regardless of the number of layers. These charge transport properties are attributed to the well-ordered molecular packing and low trap density in the films, which are enabled by the phase separation of the precursor blend films and the lamination process. In addition, OFETs based on these films have good photostability under different wavelengths of light, indicating that this approach has promising practical application prospects.

Comparative iTRAQ proteomics revealed proteins associated with lobed fin regeneration in Bichirs

Background

Polypterus senegalus can fully regenerate its pectoral lobed fins, including a complex endoskeleton, with remarkable precision. However, despite the enormous potential of this species for use in medical research, its regeneration mechanisms remain largely unknown.

Methods

To identify the differentially expressed proteins (DEPs) during the early stages of lobed fin regeneration in P. senegalus, we performed a differential proteomic analysis using isobaric tag for relative and absolute quantitation (iTRAQ) approach based quantitative proteome from the pectoral lobed fins at 3 time points. Furthermore, we validated the changes in protein expression with multiple-reaction monitoring (MRM) analysis.

Results

The experiment yielded a total of 3177 proteins and 15,091 unique peptides including 1006 non-redundant (nr) DEPs. Of these, 592 were upregulated while 349 were downregulated after lobed fin amputation when compared to the original tissue. Bioinformatics analyses showed that the DEPs were mainly associated with Ribosome and RNA transport, metabolic, ECM-receptor interaction, Golgi and endoplasmic reticulum, DNA replication, and Regulation of actin cytoskeleton.

Conclusions

To our knowledge, this is the first proteomic research to investigate alterations in protein levels and affected pathways in bichirs’ lobe-fin/limb regeneration. In addition, our study demonstrated a highly dynamic regulation during lobed fin regeneration in P. senegalus. These results not only provide a comprehensive dataset on differentially expressed proteins during the early stages of lobe-fin/limb regeneration but also advance our understanding of the molecular mechanisms underlying lobe-fin/limb regeneration.

Shanghai expert consensus on totally implantable access ports 2019

Totally implantable access ports (TIAPs) are used for patients with poor peripheral vascular support requiring central venous access. In recent years, TIAPs have been gradually accepted and promoted by patients, doctors, and nurses owing to their advantages of convenient carrying, a long maintenance period, low complications, and a high quality of life for patients. Currently, medical personnel that handle TIAP implantation and management in China are from different areas of healthcare, including surgery, internal medicine, radiology, nurse anesthesia, vascular access, etc., and many only handle TIAP as a part of their duties. Therefore, the operating procedures and steps for the diagnosis and treatment of complications of TIAP vary from person to person, resulting in different incidence and treatment methods for complications in the implantation and use of TIAP in different medical units. Based on this, we have updated the Shanghai expert consensus on TIAPs from 2015 and explored the diagnosis and treatment procedures of related complications while continuing to emphasize standardized implantation and maintenance.

Accessing the discriminatory performance of FRAIL-NH in two-class and three-class frailty and examining its agreement with the frailty index among nursing home residents in mainland China

Background

FRAIL-NH has been commonly used to assess frailty in nursing home residents and validated in many ethnic populations; however, it has not been validated in mainland China, where such an assessment tool is lacking. This study aimed to (1) assess the discriminatory performance of FRAIL-NH in two-class frailty (non-frail+ pre-frail vs. frail) and three-class frailty (non-frail vs. pre-frail vs. frail), based on the Frailty Index (FI), (2) determine the appropriate cutoff points for FRAIL-NH that distinguish two-class and three-class frailty, and (3) examine the agreement in classification between FRAIL-NH and FI.

Methods

A cross-sectional study of 302 residents aged 60 years or older from six nursing homes in Changsha was conducted. The FRAIL-NH scale and 34-item FI were used to measure frailty. Two-way and three-way receiver operating characteristic (ROC) curves were used to estimate the performance of FRAIL-NH. Cohen’s Kappa statistics were used to examine the agreement between these two measures.

Results

The agreement between FRAIL-NH and FI ranged from 0.33 to 0.55. Regardless of what FI cutoff points were based on, the volume under the ROC surface (VUS) for FRAIL-NH from the three-way ROC were higher than the VUS of a useless test (1/6), and the area under the ROC curve (AUC) for FRAIL-NH from the two-way ROC were higher than the clinically meaningless value (0.5). When using FI cutoff points of 0.20 for pre-frail and 0.45 for frail, FRAIL-NH cutoff points of 1 and 9 in classifying three-class frailty had the highest VUS and the largest correct classification rates. Whichever FI was chosen, the performance of FRAIL-NH in distinguishing between pre-frailty and frailty, and between non-frailty and pre-frailty was equivalent. According to FRAIL-NH, the proportion of individuals with frailty misclassified as pre-frailty was higher than that of individuals with non-frailty misclassified as pre-frailty.

Conclusion

FRAIL-NH can be used as a preliminary frailty screening tool in nursing homes in mainland China. FI should be further used especially for those classified as pre-frailty by FRAIL-NH. It is not advisable to simply combine adjacent two classes of FRAIL-NH to create a new frailty variable in research settings.

Effect of coupled reduced irrigation and nitrogen fertilizer on soil mite community composition in a wheat field

Groundwater and nitrogen fertilizer overuse severely threatens crop productions; thus, current ecological agriculture requires low irrigation and nitrogen fertilizer inputs. The effects of combined reduced irrigation and nitrogen fertilizer addition on soil organism (e.g., mite) community and biodiversity remain poorly understood. We analyzed soil mite community composition, wheat grain yield, and soil characteristics in a 10-year manipulation experiment with two levels of irrigation (reduced and conventional irrigation) and five nitrogen fertilizer levels (0, 70, 140, 210, and 280 kg N/ha). Reduced irrigation (20% reduction, from 280 to 220 mm) and nitrogen fertilizer (25% reduction, from 280 to 210 kg N/ha) addition did not significantly influence soil mite community and wheat yield. The relative abundances of fungivores and predators showed negative quadratic relationships with wheat yield, while that of plant parasites showed a positive relationship. The relationships between soil mite trophic groups and wheat yield revealed that we can evaluate the impacts of reduced irrigation and nitrogen fertilizer addition from the perspective of soil fauna. Soil mite community composition was altered by soil abiotic factors prior to reduced irrigation and nitrogen fertilizer addition. Overall, moderate reductions of irrigation and nitrogen fertilizer may not threaten to soil mite community and diversity or decrease crop production; in contrast, such reductions will benefit mite community development and the sustainable agriculture.

A transcriptome analysis uncovers Panax notoginseng resistance to Fusarium solani induced by methyl jasmonate

BACKGROUND

Panax notoginseng is a famous Chinese herbal medicine, but the root rot disease mainly caused by Fusarium solani severely reduces the yield and quality of its medicinal materials.

OBJECTIVE

The defense priming in P. notoginseng through exogenous application of signaling molecule will supply theoretical support for the exogenous regulation of disease resistance in P. notoginseng.

METHODS

In this study, the exogenous application of methyl jasmonate (MeJA) increased P. notoginseng's resistance to F. solani. Furthermore, the P. notoginseng transcriptome during F. solani infection was investigated through next-generation sequencing to uncover the resistance mechanism of P. notogingseng induced by MeJA.

RESULTS

The de novo assembly of transcriptome sequences produced 80,551 unigenes, and 36,771 of these unigenes were annotated by at least one database. A differentially expressed gene analysis revealed that a large number of genes related to terpenoid backbone biosynthesis, phenylalanine metabolism, and plant-pathogen interactions were predominantly up-regulated by MeJA. Moreover, jasmonic acid (JA) biosynthesis-related genes and the JA signaling pathway genes, such as linoleate 13S-lipoxygenase, allene oxide cyclase, allene oxide synthase, TIFY, defensin, and pathogenesis-related proteins, showed increased transcriptional levels after inoculation with F. solani. Notably, according to the gene expression analysis, JA and ethylene signaling pathways may act synergistically to positively regulate the defense responses of P. notoginseng to F. solani.

CONCLUSION

JA signaling appears to play a vital role in P. notoginseng responses to F. solani infection, which will be helpful in improving the disease resistance of P. notoginseng cultivars as well as in developing an environmentally friendly biological control method for root rot disease.

Biodegradation of the Neonicotinoid Insecticide Acetamiprid by Actinomycetes Streptomyces canus CGMCC 13662 and Characterization of the Novel Nitrile Hydratase Involved

Neonicotinoid insecticide pollution in soil and water poses serious environmental risks. Microbial biodegradation is an important neonicotinoid insecticide degradation pathway in the environment. In this study, 70.0% of the acetamiprid in a 200 mg/L solution was degraded by actinomycetes Streptomyces canus CGMCC 13662 (isolated from soil) in 48 h, and the acetamiprid degradation half-life was 27.7 h. Acetamiprid was degraded to IM-1-2 (( E)-1-(1-(((6-chloropyridin-3-yl)methyl)(methyl) amino)ethylidene)urea) through hydrolysis of the cyanoimine moiety. Gene cloning and overexpression indicated that a novel nitrile hydratase with three unusual subunits (AnhD, AnhE, and AnhA) without accessory protein mediated IM-1-2 formation. The purified nitrile hydratase responsible for degrading acetamiprid had a K_m of 5.85 mmol/L and a V_max of 15.99 U/mg. A homology model suggested that AnhD-Glu56 and AnhE-His21 play important roles in the catalytic efficiency of the nitrile hydratase. S. canus CGMCC 13662 could be used to remediate environments contaminated with acetamiprid.

Increases in Genistein in Medicago sativa Confer Resistance against the Pisum Host Race of Acyrthosiphon pisum

Interspecific interaction with host plants have important consequences for the host race formation of herbivorous insects. Plant secondary metabolites, particularly those that are involved in host races specializing on plants, warrant the theory of host specialization. Acyrthosiphon pisum comprises various host races that adapt to different Fabaceae plants, which provides an ideal system for determining the behavioral and physiological mechanisms underlying host-adaptive diversification. The current study evaluated the effects of host transfer on population fitness, feeding behavior and the transcriptome-wide gene expression of the two host races of A. pisum, one of which was originally from Medicago sativa and the other from Pisum sativum. The results showed that the Pisum host race of A. pisum had a lower population abundance and feeding efficiency than the Medicago host race in terms of a longer penetration time and shorter duration times of phloem ingestion when fed on M. sativa. In contrast, few differences were found in the population abundance and feeding behavior of A. pisum between the two host races when fed on P. sativum. Meanwhile, of the nine candidate phenolic compounds, only genistein was significantly affected by aphid infestation; higher levels of genistein were detected in M. sativa after feeding by the Pisum host race, but these levels were reduced relative to uninfested controls after feeding by the Medicago host race, which suggested that genistein may be involved in the specialization of the aphid host race on M. sativa. Further exogenous application of genistein in artificial diets showed that the increase in genistein reduced the survival rate of the Pisum host race but had little effect on that of the Medicago host race. The transcriptomic profiles indicated that the transcripts of six genes with functions related to detoxification were up-regulated in the Pisum host race relative to the Medicago host race of A. pisum. These results suggested that the inducible plant phenolics and associated metabolic process in aphids resulted in their differential adaptations to their Fabaceae host.

A modified approach for ultrasound-guided axillary venipuncture in the infraclavicular area: A retrospective observational study

BACKGROUND

Catheterization of the axillary vein in the infraclavicular area has important advantages in patients with long-term, indwelling central venous catheters. The two most commonly used ultrasound-guided approaches for catheterization of the axillary vein include the long-axis/in-plane approach and the short-axis/out-of-plane approach, but there are certain drawbacks to both approaches. We have modified a new approach for axillary vein catheterization: the oblique-axis/in-plane approach.

METHODS

This observational study retrospectively collected data from patients who underwent ultrasound-guided placement of an axillary vein infusion port in the infraclavicular area at the Central Venous Access Clinics of Zhongshan Hospital at Fudan University between March 2014 and May 2017. The patients' demographic data, success rate of catheterization, venous catheterization site, and immediate complications associated with catheterization were recorded.

RESULTS

Between March 2014 and May 2017, a total of 858 patients underwent placement of an axillary vein infusion port in the infraclavicular area at our center. The ultrasound-guided oblique-axis/in-plane approach was used for all patients, and the venipuncture success rate was 100%. Two cases of accidental arterial puncture and one case of local hematoma formation were reported, and no other complications, such as pneumothorax or nerve damage, were reported.

CONCLUSION

The ultrasound-guided oblique-axis/in-plane approach is a safe and reliable alternative to the routine ultrasound-guided approach for axillary venous catheterization.

Oleanane-Type Saponins Biosynthesis in Panax notoginseng via Transformation of β-Amyrin Synthase Gene from Panax japonicus

Oleanane-type saponins considered as the main medicinal ingredients in Panax japonicus are not found in Panax notoginseng. β-Amyrin synthase (βAS) was recognized as the first key enzyme in the biosynthetic branch of oleanane-type saponins. In this study, βAS gene from P. japonicus ( PjβAS) was transferred into P. notoginseng cells. Along with PjβAS expression in the transgenic cells, the expression levels of several key enzyme genes related to triterpenoid saponins biosynthesis and the content of P. notoginseng saponins were also increased. Two oleanane-type saponins, chikusetsusaponin IV and chikusetsusaponin IVa, contained in P. japonicus were first discovered in transgenic P. notoginseng cells. This study successfully constructed a biosynthetic pathway of oleanane-type saponins in P. notoginseng by introducing just one gene into the species. On the basis of this discovery and previous studies, the common biosynthetic pathway of triterpenoid saponins in Panax genus may be unified to some extent.

Abstract P4-06-30: Adipose PD-L1 modulates checkpoint blockade immunotherapy efficacy in breast cancer

Programmed death-ligand 1 (PD-L1) and its receptor programmed cell death protein 1 (PD-1) play important roles in modulating antitumor immune response and are targeted by checkpoint blockade immunotherapy. While PD-L1 expression in both tumor and host cells is associated with antitumor therapeutic efficacy, the exact contribution of PD-L1 in various tissue and cell compartments to antitumor immune response remains to be elucidated. Here we show that PD-L1 expression is markedly elevated in human and mouse mature adipocytes compared to their preadipocyte counterparts. When co-cultured with mouse splenocytes in vitro, adipocytes prevent anti-PD-L1 antibody from activating CD8+T cells. Genetic ablation of adipose PD-L1 obliterates the inhibitory effect of adipocytes on anti-PD-L1 antibody. Conversely, enforced PD-L1 expression in preadipocytes confers the antibody-inhibitory activity. GW9662, a pharmacologic inhibitor of peroxisome proliferator-activated receptor γ (PPARγ) in adipogenesis, selectively reduces PD-L1 expression in mouse adipose tissue. The same PPARγ antagonist also enhances the antitumor efficacy of checkpoint blockade antibodies for treating multiple mammary tumors. Our findings provide a previously unappreciated approach to bolster anticancer immunotherapy efficacy and suggest a mechanism for the role of adipose tissue in breast cancer progression.

Citation Format: Wu B, Sun X, Gupta HB, Yuan B, Ge F, Li J, Hu Y, Curiel TJ, Li R. Adipose PD-L1 modulates checkpoint blockade immunotherapy efficacy in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-30.

Assessing Frailty in Chinese Nursing Home Older Adults: A Comparison between the Frail-NH Scale and Frailty Index

OBJECTIVE

(1) To establish appropriate FRAIL-NH cutoff points in nursing homes in Mainland China; (2) To compare the FRAIL-NH scale and Frailty Index in assessing frailty prevalence and associated factors in nursing homes.

DESIGN

A cross-sectional study.

SETTING

Six nursing homes in Changsha, China.

PARTICIPANTS

A total of 302 residents aged 60 years or older (mean aged 82.71±8.49, 71.2% female).

MEASUREMENTS

Frailty was assessed using the 34-item Frailty Index and the FRAIL-NH scale.

RESULTS

The appropriate FRAIL-NH cutoff points to classify frail status and frailest status were 1.5 (87.6% sensitivity, 63.3% specificity) and 7.5 (94.1% sensitivity, 73.4% specificity), respectively. Based on the FRAIL-NH and Frailty Index, 69.5% (48% for frail and 21.5% for frailest), and 66.5% (60.9% for frail and 5.6% for frailest) of residents were at risk of frailty, respectively. There was no statistically significant difference in the total frailty prevalence assessed by FRAIL-NH and Frailty Index (χ2=0.617, P=0.432). The FRAIL-NH Scale is significantly associated with the Frailty Index (correlation coefficient (r) = 0.74, P < 0.001), but there was a Kappa agreement of 0.39 for frailty classification between the FRAIL-NH and Frailty Index, with the Frailty Index classifying a larger number of individuals as frail. When using FRAIL-NH scale, disease and self-reported health status were associated with frail and frailest status while age was just associated with frailest status. regarding the Frailty Index, age, diseases, medications and self-reported health status were associated with frail and frailest status.

CONCLUSION

The FRAIL-NH is a simple and effective tool to assess the overall frailty rate in nursing homes, and the Frailty Index may be more suitable capturing the multidimensionality of frailty at an individual level. Careful consideration in the selection of a frailty instrument, based on the intended purpose, is necessary.

Aphid-borne Viral Spread Is Enhanced by Virus-induced Accumulation of Plant Reactive Oxygen Species

Most known plant viruses are spread from plant to plant by insect vectors. There is strong evidence that nonpersistently transmitted viruses manipulate the release of plant volatiles to attract insect vectors, thereby promoting virus spread. The mechanisms whereby aphid settling and feeding is altered on plants infected with these viruses, however, are unclear. Here we employed loss-of-function mutations in cucumber mosaic virus (CMV) and one of its host plants, tobacco (Nicotiana tabacum), to elucidate such mechanisms. We show that, relative to a CMVΔ2b strain with a deletion of the viral suppressor of RNAi 2b protein in CMV, plants infected with wild-type CMV produce higher concentrations of the reactive oxygen species (ROS) H₂O₂ in plant tissues. Aphids on wild-type CMV-infected plants engage in shorter probes, less phloem feeding, and exhibit other changes, as detected by electrical penetration graphing technology, relative to CMVΔ2b-infected plants. Therefore, the frequency of virus acquisition and the virus load per aphid were greater on CMV-infected plants than on CMVΔ2b-infected plants. Aphids also moved away from initial feeding sites more frequently on wild-type CMV infected versus CMVΔ2b-infected plants. The role of H₂O₂ in eliciting these effects on aphids was corroborated using healthy plants infused with H₂O₂ Finally, H₂O₂ levels were not elevated, and aphid behavior was unchanged, on CMV-infected RbohD-silenced tobacco plants, which are deficient in the induction of ROS production. These results suggest that CMV uses its viral suppressor of RNAi protein to increase plant ROS levels, thereby enhancing its acquisition and transmission by vector insects.

Juvenile hormone mediates the positive effects of nitrogen fertilization on weight and reproduction in pea aphid

BACKGROUND

The positive effects of nitrogen fertilization on the performance of phytophagous insects have been reported extensively; the physiological and molecular basis involved, however, is largely unclear. Here, we test experimentally whether enhancement of juvenile hormone (JH) is responsible for the increased weight and fecundity of pea aphid (Acyrthosiphon pisum) under nitrogen fertilization.

RESULTS

Aphids fed on Medicago truncatula with nitrogen fertilization have a greater amino acid content, higher weight at the fourth instar and adult stage, and produce more offspring than those without nitrogen fertilization. Furthermore, nitrogen fertilization upregulates the transcripts of JH biosynthesis-related genes and increases JH titre at the fourth instar and adult stage, suggesting that JH is involved in the positive responses of aphids to nitrogen fertilization. Application of 100 ng JH increases adult weight and fecundity in aphids fed on M. truncatula without nitrogen fertilization. Conversely, impairing JH signalling by pharmacologically inhibiting the target of rapamycin pathway or by knocking down JH biosynthetic gene decreases adult weight and fecundity in aphids fed on M. truncatula with nitrogen fertilization, whereas application of JH rescued the phenotype.

CONCLUSION

The increased JH titre at the fourth instar and adult stage is required for the increases of weight and fecundity of A. pisum under nitrogen fertilization. © 2018 Society of Chemical Industry.

Community readiness assessment for disseminating evidence-based physical activity programs to older adults in Changsha, China: a case for Enhance®Fitness

Physical activity (PA) has declined in China due to urbanization in the past two decades. Evidence-based programs are good approaches to promote PA, but are limited in China. Adopting existing programs can be a viable option. Prior to that, readiness assessment is needed. This study aimed to assess community readiness levels for disseminating evidence-based PA programs to older adults in Changsha, China. In-person interviews were conducted with 33 participants of five districts in Changsha to assess the community readiness level in five dimensions: community knowledge of efforts, community climate, community knowledge about the issue, leadership and resources. Data was transcribed, reviewed and compared with an anchored rating scale to provide a stage of readiness score ranging from 1 (no awareness) to 9 (high level of community ownership). Participants included 14 community staff, 13 older adults, four community leaders and three health professionals. The top three barriers to disseminating PA programs were lack of appropriate locations, funding and instructors. The top three resources were availability of indoor space, chairs and loudspeakers. Community leadership was the highest-rated readiness dimension (3.3 out of 9) followed by community climate (3.2), community knowledge of efforts (3.1) and resources (2.8); knowledge about the issue scored the lowest (2.7). The overall community stage readiness score of Changsha was 3.0 out of 9. The stage of readiness for communities in Changsha, China is 'vague awareness'. Developing strategies to improve community readiness levels may increase evidence-based PA program dissemination in Changsha, China.

Genome Annotation of a Model Diatom Phaeodactylum tricornutum Using an Integrated Proteogenomic Pipeline

Diatoms comprise a diverse and ecologically important group of eukaryotic phytoplankton that significantly contributes to marine primary production and global carbon cycling. Phaeodactylum tricornutum is commonly used as a model organism for studying diatom biology. Although its genome was sequenced in 2008, a high-quality genome annotation is still not available for this diatom. Here we report the development of an integrated proteogenomic pipeline and its application for improved annotation of P. tricornutum genome using mass spectrometry (MS)-based proteomics data. Our proteogenomic analysis unambiguously identified approximately 8300 genes and revealed 606 novel proteins, 506 revised genes, 94 splice variants, 58 single amino acid variants, and a holistic view of post-translational modifications in P. tricornutum. We experimentally confirmed a subset of novel events and obtained MS evidence for more than 200 micropeptides in P. tricornutum. These findings expand the genomic landscape of P. tricornutum and provide a rich resource for the study of diatom biology. The proteogenomic pipeline we developed in this study is applicable to any sequenced eukaryote and thus represents a significant contribution to the toolset for eukaryotic proteogenomic analysis. The pipeline and its source code are freely available at https://sourceforge.net/projects/gapeproteogenomic.

Differential accumulation of leucine and methionine in red and green pea aphids leads to different fecundity in response to nitrogen fertilization

BACKGROUND

Nitrogen fertilization affects plants directly and herbivorous insects indirectly. Although insect species and even genotypes are known to differ in their responses to nitrogen fertilization, the physiological and molecular mechanisms remain unclear. This study assessed the fecundity and related regulatory signaling pathways in the green and red morphs of pea aphid (Acyrthosiphon pisum) feeding on Medicago truncatula with and without nitrogen fertilization.

RESULTS

Nitrogen fertilization significantly increased foliar amino acid concentrations and consequently increased the concentrations of several individual essential amino acids in body tissue of the green morph. The increased concentration of Leu, Ile, Met and Val was consistent with enhanced biosynthesis of these amino acids in the endosymbiont Buchnera. Under nitrogen fertilization, Leu and Met accumulated in the green morph enhanced the target of rapamycin (TOR) signaling pathway, which consequently increased fecundity by promoting vitellogenin synthesis. In the red morph, however, nitrogen fertilization did not change the concentration of essential amino acids, TOR signaling or fecundity.

CONCLUSION

Specific amino acids accumulation and the nutrient transduction pathway in pea aphids are responsible for genotype-specific fecundity in response to nitrogen fertilization, which could be used as potential target for pest control. © 2018 Society of Chemical Industry.

Corrigendum: O3-Induced Leaf Senescence in Tomato Plants Is Ethylene Signaling-Dependent and Enhances the Population Abundance of Bemisia tabaci

[This corrects the article DOI: 10.3389/fpls.2018.00764.].

Helical Nanofibrils of Block Copolymer for High-Performance Ammonia Sensors

Conjugated polymers with a helical structure have been in rapid development in recent years because of their potential applications in chemical and biological sensors. We demonstrate the fabrication and characterization of helical nanofibrils of block copolymer poly(4-iso-cyano-benzoic acid 5-(2-dimethylamino-ethoxy)-2-nitro-benzylester)- b-poly(3-hexylthiophene) (PPI(-DMAENBA)- b-P3HT) via a transfer-etching method. The density and lateral length of nanofibrils can be facilely controlled by regulating the process conditions, which, in turn, directly determine the electronic property. Organic field effect transistors based on helical nanofibrils were successfully fabricated with the highest mobility of 9.1 × 10^-3 cm²/(V s)^-1, an on/off ratio of 3.4 × 10⁵, and high bias stability. The helical nanofibrils were proved to be beneficial for obtaining a highly sensitive and selective chemical sensor. And, the transistor based on helical nanofibrils exhibits a relative response of 28.6% to 100 ppb ammonia, which is even much higher than the responses to 1 ppm ammonia for homo poly(3-hexylthiophene) nanofibrils (7%) and block copolymer nanofibrils without helical structure (0.9%). The combination of helical structure with nanofibrils may provide a new strategy to fabricate high-performance chemical sensors suitable for use in environmental monitoring, industrial and agricultural production, health care, and foodsafety.