Search

Acute hepatopancreatic necrosis disease (AHPND) is a significant deadly infectious disease in the shrimp farming industry, causing serious economic losses globally every year. Because of the rapid progress speed, lack of effective treatment and high mortality rate of AHPND, monitoring with frequent diagnostic tests is vital for a successful prevention. The conventional histopathological diagnosis fell far short of the requirement for efficient monitoring, and the polymerase chain reaction (PCR)-based molecular diagnostic methods that rely on sophisticated thermocycler and trained personnel are hardly applicable in the field. Combining the recombinase polymerase amplification (RPA) and the lateral flow strips (LFSs), a diagnostic method suitable for on-site everyday monitoring of AHPND has been established in this study. This RPA-LFS method targeted the binary toxic photorhabdus insect-related genes PirA and PirB on a virulence plasmid of the AHPND-causative Vibrio parahaemolyticus strains. The diagnostic test was completed within 30 min at 37°C and showed good specificity and good sensitivity of 20 fg DNA of the AHPND shrimp or one colony-forming unit of the causative bacterium per reaction, which was better than the administration-approved standard AP4 assay. Crude templates from sample boiling could be directly used. Tests of clinical samples showed 100% consistency of this method with the standard AP4 assay. This RPA-LFS method can be a good choice for on-site diagnosis of AHPND with quick response time, easy procedure and low demand for resources, and should have significant value for the control of spreading of this dangerous disease in farmed shrimp.

Van der Waals solids with tunable band gaps and interfacial properties have been regarded as a class of promising active materials for electrocatalytic hydrogen evolution reaction (HER). However, due to the anisotropic features, their basal planes are usually electrochemically inert, only a few unsaturated edge atoms could serve as active centers to actuate H2 generation. Hence, material utilization and productivity efficiency are insufficient for practical applications. Recently, diverse defects have been confirmed to enable tailoring atomic configurations and electronic properties of van der Waals solids, thus triggering their superior catalytic activity of in-plane atoms while introducing high amount of new active sites. In this minireview, we summarize the state-of-the-art progress of defect engineering in van der Waals solids for HER, focusing in particular on their advantages in material modification and corresponding catalytic mechanisms. We also propose the challenges and perspectives of these catalytic materials in terms of both experimental synthesis and fundamental understanding of the defect structures.

Vibrio parahaemolyticus is an important pathogenic bacterium in both food safety management and mariculture. Rapid and accurate detection technologies are critical for effective control of its outbreak and spreading. Conventional technologies and polymerase chain reaction (PCR)-based approaches have limited usage because of the requirement of laboratory instruments and trained personnel. Using the isothermal recombinase polymerase amplification (RPA) technology, several detection assays have been developed with added convenience. Combining the lateral flow strip (LFS) test with RPA can further simplify the detection. In this study, an improved RPA assay using LFS for visual detection of V. parahaemolyticus was developed. Primers were designed targeting the virulence genes and screened for amplification efficiency, nonspecific amplification, and primer-dimer formation. Probes were designed for the best primer pairs, and the weakness of LFS tests, being easily affected by primer-dependent artifacts, was overcome by sequence modifications on primers and probe. The RPA-LFS assay took 25 min at 35 to 45 °C, and showed excellent specificity. It detected as low as one colony forming unit (CFU) of V. parahaemolyticus per reaction without DNA purification, or 10 CFU/10 g spiked food samples with 2 hr of enrichment. The detection limit was better than the currently available RPA-based detection methods. Application of the RPA-LFS assay for simulated samples or real clinical samples showed accurate and consistent detection results compared to bioassay and quantitative PCR. The RPA-LFS assay provided a rapid, accurate, and convenient V. parahaemolyticus detection method suitable for on-site detection in resource-limited conditions. PRACTICAL APPLICATION: This research developed a rapid and visual detection technology for Vibrio parahaemolyticus that is not dependent on complicated equipment. The detection process takes 25 min and the result is read with the naked eye. A detection kit can be developed based on this technology for on-site detection of V. parahaemolyticus in resource-limited regions for food safety management and mariculture.

Precise modification of plant genomes, such as seamless insertion, deletion, or replacement of DNA sequences at a predefined site, is a challenging task. Gene targeting (GT) and prime editing are currently the best approaches for this purpose. However, these techniques are inefficient in plants, which limits their applications for crop breeding programs. Recently, substantial developments have been made to improve the efficiency of these techniques in plants. Several strategies, such as RNA donor templating, chemically modified donor DNA template, and tandem-repeat homology-directed repair, are aimed at improving GT. Additionally, improved prime editing gRNA design, use of engineered reverse transcriptase enzymes, and splitting prime editing components have improved the efficacy of prime editing in plants. These emerging strategies and existing technologies are reviewed along with various perspectives on their future improvement and the development of robust precision genome editing technologies for plants.

Multiple sclerosis (MS) is the most common central nervous system disease due to demyelination in young adults, and currently, there is no cure. Some experimental animal models were generated to mimic specific aspects of MS pathological characteristics. Among them, the cuprizone (CPZ)-induced mouse demyelination model presents heterogeneous pathologies with both focal and diffuse lesions. Considering that MS is a progressive disease, it is important to study the spatial and temporal characters of de- and remyelination in MS animal models. However, such data especially in some brain regions such as lateral septal area, fimbria of hippocampus, and hippocampus are still lacking. In this study, we investigated the alterations of myelin in these areas in parallel to the changes in corpus callosum using coronal sections. We found that the progression of demyelinating varied in different brain regions in C57BL/6J mice treated with CPZ for 1 to 5 weeks. This result suggests that each brain region has a distinct sensitivity to CPZ intoxication. Interestingly, activated microglia appeared not only in the active demyelinating areas but also in the non-myelinolysis regions. After CPZ withdrawal, significant remyelination was started in corpus callosum as early as 3 days. The completion of remyelination in the entire brain regions took 3 weeks. Our study detailed characterized the dynamics of myelin alterations and microglial status in the brain of the CPZ model. This information is valuable to facilitate further MS studies utilizing the CPZ model. Anat Rec, 302:2020-2029, 2019. © 2019 American Association for Anatomy.

We evaluated the acute and chronic toxicity of nitrate to juvenile fat greenling Hexagrammos otakii. The 24‐, 48‐, 72‐, and 96‐hr LC₅₀s of nitrate to 1.91 ± 0.7 g greenlings were 2,741, 2,413.5, 2,357.6, or 2,339.2 mg/L nitrate‐N, respectively. Greenlings (6.55 ± 1.83 g) were exposed to 5 mg/L (control) and 157 mg/L for 4 weeks in a recirculating aquaculture system. After 4 weeks, length, weight, feed conversion ratio, and specific growth rate were significantly (p

Summary Strategies for improving plant size are critical targets for plant biotechnology to increase vegetative biomass or reproductive yield. To improve biomass production, a codon‐optimized helix–loop–helix transcription factor (VvCEB1 opt) from wine grape was overexpressed in Arabidopsis thaliana resulting in significantly increased leaf number, leaf and rosette area, fresh weight and dry weight. Cell size, but typically not cell number, was increased in all tissues resulting in increased vegetative biomass and reproductive organ size, number and seed yield. Ionomic analysis of leaves revealed the VvCEB1 opt‐overexpressing plants had significantly elevated, K, S and Mo contents relative to control lines. Increased K content likely drives increased osmotic potential within cells leading to greater cellular growth and expansion. To understand the mechanistic basis of VvCEB1 opt action, one transgenic line was genotyped using RNA‐Seq mRNA expression profiling and revealed a novel transcriptional reprogramming network with significant changes in mRNA abundance for genes with functions in delayed flowering, pathogen–defence responses, iron homeostasis, vesicle‐mediated cell wall formation and auxin‐mediated signalling and responses. Direct testing of VvCEB1 opt‐overexpressing plants showed that they had significantly elevated auxin content and a significantly increased number of lateral leaf primordia within meristems relative to controls, confirming that cell expansion and organ number proliferation were likely an auxin‐mediated process. VvCEB1 opt overexpression in Nicotiana sylvestris also showed larger cells, organ size and biomass demonstrating the potential applicability of this innovative strategy for improving plant biomass and reproductive yield in crops.

Since 2010, second-year undergraduate students of an eight-year training program leading to a Doctor of Medicine degree or Doctor of Philosophy degree in Peking University Health Science Center (PKUHSC) have been required to enter the "Innovative talent training project." During that time, the students joined a research lab and participated in some original research work. There is a critical educational need to prepare these students for the increasing accessibility of research experience. The redesigned experimental curriculum of biochemistry and molecular biology was developed to fulfill such a requirement, which keeps two original biochemistry experiments (Gel filtration and Enzyme kinetics) and adds a new two-experiment component called "Analysis of anti-tumor drug induced apoptosis." The additional component, also known as the "project-oriented experiment" or the "comprehensive experiment," consists of Western blotting and a DNA laddering assay to assess the effects of etoposide (VP16) on the apoptosis signaling pathways. This reformed laboratory teaching system aims to enhance the participating students overall understanding of important biological research techniques and the instrumentation involved, and to foster a better understanding of the research process all within a classroom setting. Student feedback indicated that the updated curriculum helped them improve their operational and self-learning capability, and helped to increase their understanding of theoretical knowledge and actual research processes, which laid the groundwork for their future research work.

Global climate change threatens the sustainability of agriculture and agroforestry worldwide through increased heat, drought, surface evaporation and associated soil drying. Exposure of crops and forests to warmer and drier environments will increase leaf:air water vapour-pressure deficits (VPD), and will result in increased drought susceptibility and reduced productivity, not only in arid regions but also in tropical regions with seasonal dry periods. Fast-growing, short-rotation forestry (SRF) bioenergy crops such as poplar (Populus spp.) and willow (Salix spp.) are particularly susceptible to hydraulic failure following drought stress due to their isohydric nature and relatively high stomatal conductance. One approach to sustaining plant productivity is to improve water-use efficiency (WUE) by engineering crassulacean acid metabolism (CAM) into C3 crops. CAM improves WUE by shifting stomatal opening and primary CO2 uptake and fixation to the night-time when leaf:air VPD is low. CAM members of the tree genus Clusia exemplify the compatibility of CAM performance within tree species and highlight CAM as a mechanism to conserve water and maintain carbon uptake during drought conditions. The introduction of bioengineered CAM into SRF bioenergy trees is a potentially viable path to sustaining agroforestry production systems in the face of a globally changing climate.

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host that carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance.

ATP-binding cassette (ABC) transporters are implicated in a diverse range of physiological and pathophysiological processes, such as cholesterol and lipid transportation and multidrug resistance. Despite the considerable efforts made in understanding of the cellular function of ABC proteins, the regulation mechanism of this type of protein is still poorly defined. Here we report the identification and functional characterization of a novel ATPase protein, protein associated with ABC transporters (PAAT), in humans. PAAT contains a nucleotide-binding domain (NBD)-like domain and a signal for intramitochondrial sorting. We showed that PAAT is localized in both the cytoplasm and the mitochondria and has an intrinsic ATPase activity. PAAT physically interacts with the 3 known mitochondrial inner membrane ABC proteins, ABCB7, ABCB8, and ABCB10, but not ABCB1, ABCB6, or ABCG2, and functionally regulates the transport of ferric nutrients and heme biosynthesis. Significantly, PAAT deficiency promotes cell death, reduces mitochondrial potential, and sensitizes mitochondria to oxidative stress-induced DNA damages. Our experiments revealed that PAAT is a novel ATPase and a trans-regulator of mitochondrial ABC transporters that plays an important role in the maintenance of mitochondrial homeostasis and cell survival.

There are a large number of non-family (NF) genes that do not cluster into families with three or more members per genome. While gene families have been extensively studied, a systematic analysis of NF genes has not been reported. We performed comparative studies on NF genes in 14 plant species. Based on the clustering of protein sequences, we identified ~94,000 NF genes across these species that were divided into five evolutionary groups: Viridiplantae-wide, angiosperm-specific, monocot-specific, dicot-specific, and those that were species-specific. Our analysis revealed that the NF genes resulted largely from less frequent gene duplications and/or a higher rate of gene loss after segmental duplication relative to genes in both low-copy-number families (LF; 3 10 copies per genome) and high-copy-number families (HF; >10 copies). Furthermore, we identified functions enriched in the NF gene set as compared with the HF genes. We found that NF genes were involved in essential biological processes shared by all plant lineages (e.g., photosynthesis and translation), as well as gene regulation and stress responses associated with phylogenetic diversification. In particular, our analysis of an Arabidopsis protein-protein interaction network revealed that hub proteins with the top 10% most connections were over-represented in the NF set relative tomore » the HF set. This research highlights the roles that NF genes may play in evolutionary and functional genomics research.« less

Shade avoidance signaling involves perception of incident red/far-red (R/FR) light by phytochromes (PHYs) and modulation of downstream transcriptional networks. Although these responses are well studied in Arabidopsis, little is known about the role of PHYs and the transcriptional responses to shade in the woody perennial Populus. Tissue expression and subcellular localization of Populus PHYs was studied by quantitative real-time PCR (qRT-PCR) and protoplast transient assay. Transgenic lines with altered PHYB1 and/or PHYB2 expression were used in phenotypic assays and transcript profiling with qRT-PCR. RNA-Seq was used to identify transcriptional responses to enriched FR light. All three PHYs were differentially expressed among tissue types and PHYBs were targeted to the nucleus under white light. Populus PHYB1 rescued Arabidopsis phyB mutant phenotypes. Phenotypes of Populus transgenic lines and the expression of candidate shade response genes suggested that PHYB1 and PHYB2 have distinct yet overlapping functions. RNA-Seq analysis indicated that genes associated with cell wall modification and brassinosteroid signaling were induced under enriched FR light in Populus. This study is an initial attempt at deciphering the role of Populus PHYs by evaluating transcriptional reprogramming to enriched FR and demonstrates functional diversity and overlap of the Populus PHYB1 and PHYB2 in regulating shade responses.

The heat shock response continues to be layered with additional complexity as interactions and crosstalk among heat shock proteins (HSPs), the reactive oxygen network and hormonal signalling are discovered. However, comparative analyses exploring variation in each of these processes among species remain relatively unexplored. In controlled environment experiments, photosynthetic response curves were conducted from 22 to 42 °C and indicated that temperature optimum of light-saturated photosynthesis was greater for Glycine max relative to Arabidopsis thaliana or Populus trichocarpa. Transcript profiles were taken at defined states along the temperature response curves, and inferred pathway analysis revealed species-specific variation in the abiotic stress and the minor carbohydrate raffinose/galactinol pathways. A weighted gene coexpression network approach was used to group individual genes into network modules linking biochemical measures of the antioxidant system to leaf-level photosynthesis among P. trichocarpa, G. max and A. thaliana. Networkenabled results revealed an expansion in the G.max HSP17 protein family and divergence in the regulation of the antioxidant and heat shock modules relative to P. trichocarpa and A. thaliana. These results indicate that although the heat shock response is highly conserved, there is considerable species-specific variation in its regulation.

Jin-Gui Chen (Corresponding author) Abscisic acid (ABA) is the key plant stress hormone. Consistent with the earlier studies in support of the presence of both membrane- and cytoplasm-localized ABA receptors, recent studies have identified multiple ABA receptors located in various subcellular locations. These include a chloroplast envelope-localized receptor (the H subunit of Chloroplast Mg(2+) -chelatase/ABA Receptor), two plasma membrane-localized receptors (G-protein Coupled Receptor 2 and GPCR-type G proteins), and one cytosol/nucleus-localized Pyrabactin Resistant (PYR)/PYR-Like (PYL)/Regulatory Component of ABA Receptor 1 (RCAR). Although the downstream molecular events for most of the identified ABA receptors are currently unknown, one of them, PYR/PYL/RCAR was found to directly bind and regulate the activity of a long-known central regulator of ABA signaling, the A-group protein phosphatase 2C (PP2C). Together with the Sucrose Non-fermentation Kinase Subfamily 2 (SnRK2s) protein kinases, a central signaling complex (ABA-PYR-PP2Cs-SnRK2s) that is responsible for ABA signal perception and transduction is supported by abundant genetic, physiological, biochemical and structural evidence. The identification of multiple ABA receptors has advanced our understanding of ABA signal perception and transduction while adding an extra layer of complexity.

Silver nanospheres (Ag NSs) buffer layers were introduced via a solution casting process to enhance the light absorption in poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) bulk heterojunction organic solar cells. These Ag NSs, as surface plasmons, could increase the optical electric field in the photoactive layer whilst simultaneously improving the light scattering. As a result, this buffer layer improves the light absorption of P3HT:PCBM blend and consequently improves the external quantum efficiency (EQE) of organic solar cells. In this work, different sizes of Ag NSs plasmon-enhanced layer were investigated, with the aim of optimizing the performance of devices. UV-vis spectrometer measurement demonstrates that the total optical absorption of P3HT:PCBM blend films in the spectral range of 350–650 nm is increased by ∼4 and 6% with incorporation of the 20 and 40 nm Ag NSs, respectively. The Jsc was shown to increase by ∼21 and 24% for 20 and 40 nm Ag NSs, respectively. This is due to the extra photogenerated excitons by the plasmonic resonance of Ag NSs. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)