Quantitative Assessment of Acute Intracranial Clot and Collaterals on High Resolution Magnetic Resonance Imaging.

INTRODUCTION: There has been an increasing demand for imaging methods that provide a comprehensive evaluation of intracranial clot and collateral circulation, which are helpful for clinical decision-making and predicting functional outcomes. We aimed to quantitatively evaluate acute intracranial clot burden and collaterals on high-resolution magnetic resonance imaging (HR-MRI). METHODS: We analyzed acute ischemic stroke patients with internal carotid artery or middle cerebral artery occlusion in a prospective multicenter study. The clot burden was scored on a scale of 0-10 based on the clot location on HR-MRI. The collateral score was assigned on a scale of 0-3 using the minimum intensity projection from HR-MRI. Uni- and multivariable logistic regression analyses were performed to assess their correlation with clinical outcome (modified Rankin Scale >2 at 90 days). Thresholds were defined to dichotomize into low and high score groups and predictive performances were assessed for clinical and radiologic outcomes. RESULTS: Ninety-nine patients (mean age of 60.77 ± 11.54 years) were included in the analysis. The interobserver correlation was 0.89 (95% CI: 0.77-0.95) for the clot burden score and 0.78 (95% CI: 0.53-0.90) for the collateral score. Multivariable logistic regression analysis demonstrated that the collateral score (odds ratio: 0.41, 95% CI: 0.19-0.90) was significantly associated with clinical outcomes. A better functional outcome was observed in the group with clot burden scores greater than 7 (p=0.011). A smaller final infarct size and a higher diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score were observed in the group with collateral scores greater than 1 (all p<0.05). CONCLUSIONS: HR-MRI offers a new tool for quantitative assessment of clot burden and collaterals simultaneously in future clinical practices and research endeavors.

Anisotropic fluid flows in black phosphorus nanochannels.

With the development of advanced micro/nanoscale technologies, two-dimensional materials have emerged from laboratories and have been applied in practice. To investigate the mechanisms of solid-liquid interactions in potential applications, molecular dynamics simulations are employed to study the flow behavior of n-dodecane (C12) molecules confined in black phosphorus (BP) nanochannels. Under the same external conditions, a significant difference in the velocity profiles of fluid molecules is observed when flowing along the armchair and zigzag directions of the BP walls. The average velocity of C12 molecules flowing along the zigzag direction is 9-fold higher than that along the armchair direction. The friction factor at the interface between C12 molecules and BP nanochannels and the orientations of C12 molecules near the BP walls are analyzed to explain the differences in velocity profiles under various flow directions, external driving forces, and nanochannel widths. The result shows that most C12 molecules are oriented parallel to the flow direction along the zigzag direction, leading to a relatively smaller friction factor hence a higher average velocity. In contrast, along the armchair direction, most C12 molecules are oriented perpendicular to the flow direction, leading to a relatively larger friction factor and thus a lower average velocity. This work provides important insights into understanding the anisotropic liquid flows in nanochannels.

Dual Gene Detection of H5N1 Avian Influenza Virus Based on Dual RT-RPA.

The H5N1 avian influenza virus seriously affects the health of poultry and humans. Once infected, the mortality rate is very high. Therefore, accurate and timely detection of the H5N1 avian influenza virus is beneficial for controlling its spread. This article establishes a dual gene detection method based on dual RPA for simultaneously detecting the HA and M2 genes of H5N1 avian influenza virus, for the detection of H5N1 avian influenza virus. Design specific primers for the conserved regions of the HA and M2 genes. The sensitivity of the dual RT-RPA detection method for HA and M2 genes is 1 × 10-7 ng/µL. The optimal primer ratio is 1:1, the optimal reaction temperature is 40 °C, and the optimal reaction time is 20 min. Dual RT-RPA was used to detect 72 samples, and compared with RT-qPCR detection, the Kappa value was 1 (p value < 0.05), and the clinical sample detection sensitivity and specificity were both 100%. The dual RT-RPA method is used for the first time to simultaneously detect two genes of the H5N1 avian influenza virus. As an accurate and convenient diagnostic tool, it can be used to diagnose the H5N1 avian influenza virus.

Effectiveness of typodont, quail egg and virtual simulation for ultrasonic periodontal scaling teaching among pre-clinical students: a randomized trial.

BACKGROUND: This study aimed to compare the efficacy of three different techniques, namely virtual simulation technology (VS), traditional pathological typodont (TT), and quail egg (QE), in pre-clinical training of periodontal ultrasonic scaling. It also aimed to propose an integrated teaching approach for ultrasonic scaling teaching. METHODS: This single-blind randomized multi-arm trial enrolled 108 fourth-year students from Guanghua School of Stomatology at Sun Yat-sen University. The participants were randomly, evenly assigned to VS, TT, or QE group. First, the participants received theoretical review on ultrasonic scaling and demonstrative teaching. Then in the 90-minute operation training by group, students used traditional typodont equipped in head-simulators, raw quail eggs, or scaling module of the UniDental VS system respectively. Then all participants practiced on pathological models for 30 min. In the final operation examination, participants were instructed to remove the supra- and sub-gingival calculi pre-set on designated teeth by ultrasonic scalers within 30 min. Their performances were evaluated by residual calculus rate and a multi-perspective scoring scale. After the examination, questionnaires were provided to assess the teaching effects of each method and the fidelity of VS. Statistical analysis was carried out using one-way, two-way ANOVA, and multiple t-test. RESULTS: Students in VS group had significant higher total test scores than QE group (87.89 ± 6.81, 83.53 ± 8.14) and TT group (85.03 ± 6.81). VS group scored higher in several dimensional comparisons with the other two groups, especially in difficult situations. QE group had higher scores particularly in force application and supra-gingival scaling. TT group scored the highest in pivot stability practice and body position training. Students gave higher scores when assessing the fidelity of VS than experienced teachers. CONCLUSION: The study highlights the importance of specialized pre-clinical training on ultrasonic scaling for dental students. The methods adopted in current study (VS, TT and QE) each offered unique advantages in education, which can be combined to create an integrative teaching procedure. This procedure aims to provide an effective, advisable and normative pre-clinical training procedure for ultrasonic scaling. By utilizing the strengths of each method, dental educators can deliver high-quality training and ensure that students are well-prepared for clinical practice.

The effect of virtual simulation technology applied to undergraduate teaching of periodontal probing.

INTRODUCTION: The rise of virtual simulation technology and dental simulators has created a new pedagogical approach for undergraduate medical education. The purpose of this study is to evaluate the effect of virtual simulation (VS) technology on improving the students' comprehensive abilities in periodontal probing teaching in pre-practicum periodontology, such as increasing the accuracy of probing, tactile perception and performance on force control. MATERIALS AND METHODS: Twenty students were randomly selected among the fourth-year students and equally divided into VS technology teaching group (VS group) and traditional teaching group (TT group) by drawing half lots. One day later, students were required to probe the periodontal pathology model. The consistency rate between PD measurements and PD reference values, time consumption and final exam scores were recorded and statistically analysed using an unpaired Student's t test and p < .05 was considered statistical significance. Finally, questionnaires relating to teaching methods evaluation and the fidelity of the digital VS training system were distributed to students and teachers. RESULTS: VS group had a significantly higher consistency rate (72.976 ± 6.811%) than TT group (64.107 ± 4.988%, p = .004). To specify, the difference of consistency rates between the two groups in posterior teeth was larger than anterior teeth. Similarly, a larger difference was also found in proximal surfaces compared with buccal-lingual surfaces. As the pocket depth increased, the difference between the two groups increased too. These results indicated that VS is more efficient in complicated parts of periodontal probing teaching. In addition, students in VS group spent less time and gained a higher score than TT group (p < .05). The overall satisfaction rating in VS group was significantly higher than TT group. Lastly, teachers gave significant lower scores than students concerning the fidelity of VS system. CONCLUSION: Although there are much to improve, VS technology has obvious advantages in periodontal probing teaching in pre-practicum periodontology.

Baseline C-reactive protein predicts efficacy of the first-line immune checkpoint inhibitors plus chemotherapy in advanced lung squamous cell carcinoma: a retrospective, multicenter study.

AIMS: To investigate the predictive value of baseline C-reactive protein (CRP) levels on the efficacy of chemotherapy plus immune checkpoint inhibitors (ICI) in patients with advanced lung squamous cell carcinoma (LSCC). MATERIALS AND METHODS: In this retrospective multicenter study spanning from January 2016 to December 2020, advanced LSCC patients initially treated with chemotherapy or a combination of chemotherapy and ICI were categorized into normal and elevated CRP subgroups. The relationship between CRP levels and treatment outcomes was analyzed using multivariate Cox proportional hazards models and multivariate logistic regression, focusing primarily on the progression-free survival (PFS) endpoint, and secondarily on overall survival (OS) and objective response rate (ORR) endpoints. Survival curves were generated using the Kaplan-Meier method, with the log-rank test used for comparison between groups. RESULTS: Of the 245 patients evaluated, the 105 who received a combination of chemotherapy and ICI with elevated baseline CRP levels exhibited a significant reduction in PFS (median 6.5 months vs. 11.8 months, HR, 1.78; 95% CI: 1.12-2.81; p = 0.013) compared to those with normal CRP levels. Elevated CRP was identified as an independent risk factor for poor PFS through multivariate-adjusted analysis. However, among the 140 patients receiving chemotherapy alone, baseline CRP levels did not significantly influence PFS. Furthermore, within the combination therapy group, there was a notable decrease in the ORR (51% vs. 71%, p = 0.035), coupled with a significantly shorter OS (median 20.9 months vs. 31.5 months, HR, 2.24; 95% CI: 1.13-4.44; p = 0.033). CONCLUSION: In patients with advanced LSCC, elevated baseline CRP levels were identified as an independent predictive factor for the efficacy of combination therapy with chemotherapy and ICI, but not in chemotherapy alone. This suggests that CRP may be a valuable biomarker for guiding treatment strategies.

Cerebrospinal fluid circulating tumor DNA contributes to the detection and characterization of leptomeningeal metastasis in non-small cell lung cancer.

PURPOSE: Cerebrospinal fluid (CSF) has revealed the unique genetic characteristics of leptomeningeal metastasis (LM) from non-small cell lung cancer (NSCLC). However, the research in this area is still very limited. METHODS: Patients with LM from NSCLC (n = 80) were retrospectively analyzed. Circulating tumor DNA (ctDNA) in CSF was tested by next-generation sequencing (NGS), with paired extracranial tissue or plasma samples included for comparison. An independent non-LM cohort (n = 100) was also analyzed for comparative purposes. Clinical outcomes were compared with Kaplan-Meier log-rank test and Cox proportional hazards methodologies. RESULTS: An overwhelming 93.8% of patients carried druggable mutations in NSCLC LM, with EGFR (78.8%) being the most prevalent. Notably, 4 patients who tested negative for driver genes in extracranial samples surprisingly showed EGFR mutations in their CSF and subsequently benefited from targeted therapy. There was a clear difference in genetic profiles between CSF and extracranial samples, with CSF showing more driver gene detections, increased Copy Number Variations (CNVs), and varied resistance mechanisms among individuals. Abnormalities in cell-cycle regulatory molecules were highly enriched in LM (50.9% vs 31.0%, p = 0.017), and CDKN2A/2B deletions were identified as an independent poor prognostic factor for LM patients, with a significant reduction in median OS (p = 0.013), supported by multivariate analysis (HR 2.63, 95% CI 1.32-5.26, p = 0.006). CONCLUSIONS: CSF-based ctDNA analysis is crucial for detecting and characterizing genetic alterations in NSCLC LM. The distinct genetic profiles in CSF and extracranial tissues emphasize the need for personalized treatment approaches.

High-resolution magnetic resonance imaging of acute intracranial artery thrombus.

BACKGROUND AND PURPOSE: The development of high-resolution magnetic resonance imaging (HR-MRI) has enabled submillimeter-level evaluation of intracranial artery plaque and luminal thrombus. We sought to investigate the value of HR-MRI in assessing the pathogenesis of acute intracranial artery thrombus. METHODS: We examined the presence of intracranial thrombus on three-dimensional T1-weighted HR-MRI in acute ischemic stroke patients with intracranial artery occlusion on magnetic resonance angiography. We defined two thrombus-related HR-MRI features (peri-thrombus plaque and distal residual flow beyond the thrombus) and analyzed their association with potential embolic sources. RESULTS: Luminal thrombus and a shrunken artery without luminal thrombus were detected in 162 (96.4%) and six (3.6%) of 168 patients with intracranial artery occlusion, respectively. Among 111 patients with culprit major artery thrombus, peri-thrombus plaques were observed in 46.8% and distal residual flow beyond the thrombus in 64.0%. Patients with peri-thrombus plaque had a higher prevalence of diabetes (44.2% vs. 25.4%; p = 0.037), a lower prevalence of potential sources of cardioembolism (0% vs. 16.9%; p = 0.002), and a nonsignificantly lower prevalence of potential embolic sources from extracranial arteries (9.6% vs. 20.3%; p = 0.186) than those without. Patients with distal residual flow beyond the thrombus had a lower prevalence of potential sources of cardioembolism (1.4% vs. 22.5%; p < 0.001) and smaller infarct volumes (5.0 [1.4-12.7] mL vs. 16.6 [2.4-94.6] mL; p = 0.012) than those without. CONCLUSIONS: Our study showed that HR-MRI helps clarify the pathogenesis of acute intracranial artery thrombus. The presence of peri-thrombus plaque and distal residual flow beyond the thrombus favor the stroke mechanism of atherosclerosis rather than cardioembolism.

Emotional Appeals and Norms: How Normative Perceptions Moderate the Persuasive Impacts of Discrete Emotional Appeals within Tobacco Pictorial Warnings in China.

Tobacco pictorial warnings could employ a variety of emotional appeals to enhance effectiveness; however, little research exists to guide the selection of discrete emotional appeals. Further, it remains unclear how contextual pro-smoking norms might influence the persuasive impacts of discrete emotional appeals within pictorial warnings, especially in China, where the overall smoking rate and social acceptance remain high. To fill these gaps, this study leveraged the largest set of pictorial warnings (K = 510) tested to date. Using a randomized large-K multiple-message design, we evaluated the impacts of disgust, fear, self-anger, contempt, shame, and hope appeals among Chinese adult male smokers (N = 2,306) on perceived message effectiveness (PME). Results showed that fear, self-anger, shame, and hope appeals significantly increased PME, while disgust and contempt appeals appeared less effective. Importantly, the PME of nearly all emotional appeals - except hope appeals - was weakened for Chinese adult male smokers with higher pro-smoking normative perceptions, highlighting the importance of considering local contextual influences when implementing pictorial warnings.

Photosynthetic Fixation of CO2 in Alkenes by Heterogeneous Photoredox Catalysis with Visible Light.

Light-driven fixation of CO2 in organics has emerged as an appealing alternative for the synthesis of value-added fine chemicals. Challenges remain in the transformation of CO2 as well as product selectivity due to its thermodynamic stability and kinetic inertness. Here we develop a boron carbonitride (BCN) with the abundant terminal B/N defects around the mesoporous walls, which essentially enhances surface active sites as well as charge transfer kinetics, boosting the overall rate of CO2 adsorption and activation. In this protocol, anti-Markovnikov hydrocarboxylation of alkenes with CO2 to an extended carbon chain is achieved with good functional group tolerance and specific regioselectivity under visible-light irradiation. The mechanistic studies demonstrate the formation of CO2 radical anion intermediate on defective boron carbonitride, leading to the anti-Markovnikov carboxylation. Gram-scale reaction, late-stage carboxylation of natural products and synthesis of anti-diabetic GPR40 agonists reveal the utility of this method. This study sheds new insight on the design and application of metal-free semiconductors for the conversion of CO2 in an atom-economic and sustainable manner.

High-performance polarization-independent black phosphorus refractive index sensors enabled by a single-layer pattern design.

The in-plane orientation-dependent electrical and optical properties of two-dimensional (2D) anisotropic materials attract significant attention because of the intriguing underlying physics. However, this feature limits their further development in polarization-independent applications such as refractive index sensors and light absorbers. In this paper, polarization-independent optical properties of black phosphorous (BP) metadevices are achieved by the design of a single-layer pattern of 2D anisotropic material. Finite-difference time-domain (FDTD) simulation results indicate that the absorption spectrum remains unchanged as the polarization angle of the incident light varies from 0° to 360°. The performance of the BP metadevices when used as refractive index sensors is also studied. The results show that the polarization-independent BP sensors exhibit high sensitivity and figures of merit (FOMs). This work opens up the possibility of fabricating optically polarization-independent devices based on a single-layer pattern of 2D anisotropic material.

Molecular understanding of the effect of hydrogen on graphene growth by plasma-enhanced chemical vapor deposition.

Plasma-enhanced chemical vapor deposition (PECVD) provides a low-temperature, highly-efficient, and catalyst-free route to fabricate graphene materials by virtue of the unique properties of plasma. In this paper, we conduct reactive molecular dynamics simulations to theoretically study the detailed growth process of graphene by PECVD at the atomic scale. Hydrocarbon radicals with different carbon/hydrogen (C/H) ratios are employed as dissociated precursors in the plasma environment during the growth process. The simulation results show that hydrogen content in the precursors significantly affects the growth behavior and properties of graphene (e.g., the quality of obtained graphene, which is indicated by the number of hexagonal carbon rings formed in the graphene sheets). Moreover, increasing the content of hydrogen in the precursors is shown to reduce the growth rate of carbon clusters, and prevent the formation of curved carbon structures during the growth process. The findings provide a detailed understanding of the fundamental mechanisms regarding the effects of hydrogen on the growth of graphene in a PECVD process.

"I Do Not Trust Health Information Shared by My Parents": Credibility Judgement of Health (Mis)information on Social Media in China.

The surge of health misinformation on social media poses a threat to public health. This qualitative study reports how users process health misinformation from the dominant strong-tie social media, WeChat, in China. We conducted ten on-site focus groups involving 76 adult participants. Drawing on the apomediation theory and the dual processing model of credibility assessment, we found the heuristic approach to processing health information was the dominant route of engagement. We identified four categories of credibility assessment cues, including (1) expertise, authority, and commercial intent of original sources, (2) expertise of apomediaries (i.e. social media information sharers) and generational bias, (3) clickbait and sensational content versus objective scientific style, and (4) disconfirmation versus confirmation bias. We highlight that apomediaries are playing an increasingly important role in informing credibility judgment. Specifically, younger adults have formed a generational bias of deeming older apomediaries as cues of lower credibility.

How Social Media Exposure to Health Information Influences Chinese People's Health Protective Behavior during Air Pollution: A Theory of Planned Behavior Perspective.

Haze has become one of the most life-threatening problems in China and affects over one billion Chinese people's health. Chinese people have become more dependent on receiving health information from social media, especially Weibo and WeChat, which shapes their health perceptions and behaviors. To investigate how Chinese people's exposure to health information on social media influenced their health protective behaviors in response to haze, particularly wearing a PM2.5 anti-haze mask, we conducted a longitudinal web-based survey of mainland Chinese. The results from the structural equation modeling showed that (a) attitude and descriptive norm positively mediated the relationships between using Weibo for health information and behavioral intention while descriptive norm negatively mediated the relationship between using WeChat for health information and intention, and that (b) attitude, descriptive norm, and injunctive norm significantly predicted behavioral intention and wearing mask, but perceived behavior control did not. Theoretical and practical implications are discussed.

Air pollution in China: health information seeking and protective behaviors.

Haze has become one of the most life-threatening problems in China. Chinese people become more dependent on receiving health information from social media, especially WeChat, which shapes their health perceptions and behaviors. Despite the prevalence of health information-seeking behavior (HISB) on WeChat, the predicting factors and consequences of Chinese people's haze HISB using WeChat remain unclear. To fill this gap, a hypothesized model was proposed under the risk perception attitude framework and tested with a longitudinal web-based survey of Chinese people residing in Mainland China, to understand the antecedents and behavioral outcomes of HISB on WeChat. The results from the structural equation modeling showed that perceived risk significantly predicted haze HISB on WeChat, which predicted the intention of wearing PM2.5 mask but not reducing outdoor exercises. The efficacy beliefs of both protective behaviors were not significant predictor of haze HISB. Theoretical and practical implications were discussed.

FHL1-related clinical, muscle MRI and genetic features in six Chinese patients with reducing body myopathy.

Reducing body myopathy is a rare X-linked myopathy characterized by the presence of reducing bodies. The causative gene has been identified as FHL1. We presented with the clinical, muscle magnetic resonance imaging and genetic features of 6 unrelated Chinese patients with reducing body myopathy. We divided the patients into 2 groups according to their age at onset. In addition to limb muscle weakness, pronounced axial muscle involvement was a striking feature common to both groups. Muscle magnetic resonance imaging revealed fatty infiltration predominantly in the postero-medial muscles of the thigh and the soleus muscle of the calf, sparing the gluteus and sartorius muscles. Muscle pathology demonstrated the muscle fibres with reducing bodies distributed in small groups. Genetic analysis revealed FHL1 hemizygote variants in the 6 patients, including 4 novel and 2 reported variants. These variants were located in the LIM2 domain of FHL1 in 4 patients, but 2 located in the LIM4 domain. To the best of our knowledge, this is the first report of reducing body myopathy in the Chinese population. Our findings expand the genetic spectrum of reducing body myopathy.

Relationship between the geometry patterns of vertebrobasilar artery and atherosclerosis.

BACKGROUND: The plaques at the dorsal or lateral wall of basilar artery (BA) are associated with pontine infarcts. We sought to explore the correlations between vertebrobasilar artery geometry and BA plaque locations. METHODS: We retrospectively analyzed the imaging and clinical data of 84 patients with BA atherosclerosis. On three-dimensional time-of-flight images, a side to side diameter difference of bilateral vertebral artery (VA) and BA bending were assessed. The vertebrobasilar artery geometry was qualitatively classified into four basic configurations: Walking, Tuning Fork, Dominant-Lambda, and Hypoplasia-Lambda. On high-resolution magnetic resonance imaging, the plaques were categorized based on the involvement of the ventral, dorsal, or lateral sides of BA wall. The relationships between vertebrobasilar artery geometry parameters and plaque locations were analyzed. RESULTS: Left VA dominance was identified in 28(33%) patients, and right VA dominance in 22(26%) patients. BA bending were detected in 49 patients. There were no significant correlations between the diameter difference/ratio of VA diameters and plaque locations, or between BA bending and plaque locations. BA plaques were evenly distributed in the vertebrobasilar arteries with Tuning Fork and Dominant-Lambda configurations. In Hypoplasia-Lambda group, however, plaques were more frequently located at the dorsal wall (58.57%) than at the ventral (14.43%) and lateral wall (26.71%; P = 0.001). In Walking group, the plaques more likely occurred at the lateral (49.79%) and dorsal (35.07%) wall than at the ventral wall (14.86%, P = 0.02). CONCLUSIONS: The geometric configurations of vertebrobasilar artery strongly influence the BA plaque locations. Further prospective studies are warranted to testify whether Hypoplasia-Lambda and Walking configurations are independent risk factors for pontine infarcts.

DMDtoolkit: a tool for visualizing the mutated dystrophin protein and predicting the clinical severity in DMD.

BACKGROUND: Dystrophinopathy is one of the most common human monogenic diseases which results in Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Mutations in the dystrophin gene are responsible for both DMD and BMD. However, the clinical phenotypes and treatments are quite different in these two muscular dystrophies. Since early diagnosis and treatment results in better clinical outcome in DMD it is essential to establish accurate early diagnosis of DMD to allow efficient management. Previously, the reading-frame rule was used to predict DMD versus BMD. However, there are limitations using this traditional tool. Here, we report a novel molecular method to improve the accuracy of predicting clinical phenotypes in dystrophinopathy. We utilized several additional molecular genetic rules or patterns such as "ambush hypothesis", "hidden stop codons" and "exonic splicing enhancer (ESE)" to predict the expressed clinical phenotypes as DMD versus BMD. RESULTS: A computer software "DMDtoolkit" was developed to visualize the structure and to predict the functional changes of mutated dystrophin protein. It also assists statistical prediction for clinical phenotypes. Using the DMDtoolkit we showed that the accuracy of predicting DMD versus BMD raised about 3% in all types of dystrophin mutations when compared with previous methods. We performed statistical analyses using correlation coefficients, regression coefficients, pedigree graphs, histograms, scatter plots with trend lines, and stem and leaf plots. CONCLUSIONS: We present a novel DMDtoolkit, to improve the accuracy of clinical diagnosis for DMD/BMD. This computer program allows automatic and comprehensive identification of clinical risk and allowing them the benefit of early medication treatments. DMDtoolkit is implemented in Perl and R under the GNU license. This resource is freely available at http://github.com/zhoujp111/DMDtoolkit , and http://www.dmd-registry.com .

Global transcriptome analysis of Huperzia serrata and identification of critical genes involved in the biosynthesis of huperzine A.

BACKGROUND: Huperzia serrata (H. serrata) is an economically important traditional Chinese herb with the notably medicinal value. As a representative member of the Lycopodiaceae family, the H. serrata produces various types of effectively bioactive lycopodium alkaloids, especially the huperzine A (HupA) which is a promising drug for Alzheimer's disease. Despite their medicinal importance, the public genomic and transcriptomic resources are very limited and the biosynthesis of HupA is largely unknown. Previous studies on comparison of 454-ESTs from H. serrata and Phlegmariurus carinatus predicted putative genes involved in lycopodium alkaloid biosynthesis, such as lysine decarboxylase like (LDC-like) protein and some CYP450s. However, these gene annotations were not carried out with further biochemical characterizations. To understand the biosynthesis of HupA and its regulation in H. serrata, a global transcriptome analysis on H. Serrata tissues was performed. RESULTS: In this study, we used the Illumina Highseq4000 platform to generate a substantial RNA sequencing dataset of H. serrata. A total of 40.1 Gb clean data was generated from four different tissues: root, stem, leaf, and sporangia and assembled into 181,141 unigenes. The total length, average length, N50 and GC content of unigenes were 219,520,611 bp, 1,211 bp, 2,488 bp and 42.51%, respectively. Among them, 105,516 unigenes (58.25%) were annotated by seven public databases (NR, NT, Swiss-Prot, KEGG, COG, Interpro, GO), and 54 GO terms and 3,391 transcription factors (TFs) were functionally classified, respectively. KEGG pathway analysis revealed that 72,230 unigenes were classified into 21 functional pathways. Three types of candidate enzymes, LDC, CAO and PKS, responsible for the biosynthesis of precursors of HupA were all identified in the transcripts. Four hundred and fifty-seven CYP450 genes in H. serrata were also analyzed and compared with tissue-specific gene expression. Moreover, two key classes of CYP450 genes BBE and SLS, with 23 members in total, for modification of the lycopodium alkaloid scaffold in the late two stages of biosynthesis of HupA were further evaluated. CONCLUSION: This study is the first report of global transcriptome analysis on all tissues of H. serrata, and critical genes involved in the biosynthesis of precursors and scaffold modifications of HupA were discovered and predicted. The transcriptome data from this work not only could provide an important resource for further investigating on metabolic pathways in H. serrata, but also shed light on synthetic biology study of HupA.