D-amino acid oxidase (DAO) rare genetic missense variant p.Pro103Leu and gastric cancer

Gastric cancer is prevalent in the Asian population. Genetic predisposition to gastric cancer is not fully understood. Recent studies have demonstrated that D-amino acid oxidase (DAO), a multifunctional enzyme, protects the mucosa of gastrointestinal (GI) tracts by generating hydrogen sulfide (H₂S) in the stomach of rodents. The present study surveyed rare germline variants in the human DAO gene with regard to the incidence of gastric cancer. The consecutive autopsy cases registered in the JG-SNP database (n=2,343; mean age, 80 years) were employed and genotyped with Exome Bead-Chips. There were three non-synonymous rare variants, p.R22H, p.P103L and p.R283Q, of which the minor allele frequencies were 0.09, 0.21 and 0.02%, respectively. Carriers of these variants were surveyed, the results of which revealed that 4 out of 10 patients with the p.P103L variant had gastric cancer (Fisher's exact test, P=0.018). All 4 patients were men with drinking and smoking habits. Among the other 6 women, there was one incidence of small intestine cancer and one of colon cancer. Neither p.R22H nor p.R283Q carriers had GI cancer. DAO p.P103L is reported to be a modifier of amyotrophic lateral sclerosis (ALS) and may potentially be a hypomorphic allele. Thus, it is hypothesized that this rare variant might have affected protection against gastric mucosal damage through H₂S signaling in the mucosa, which leads to high prevalence of gastric cancer. The role of rare variant DAO p.P103L warrants further investigation in larger cohorts.

Efficacy and Safety of Nab-Paclitaxel Plus S-1 versus Nab-Paclitaxel Plus Gemcitabine for First-Line Chemotherapy in Advanced Pancreatic Ductal Adenocarcinoma

Objective

Nab-paclitaxel plus gemcitabine (nab-P/G) has been established as a standard first-line treatment in metastatic pancreatic ductal adenocarcinoma (PDAC). S-1, as an oral fluoropyrimidine derivative, demonstrated effective for PDAC. This study aimed to evaluate the efficacy and safety of first-line chemotherapy with nab-paclitaxel plus S-1 (nab-P/S) versus nab-P/G in patients with advanced PDAC.

Methods

Patients with advanced PDAC receiving nab-P/S (n = 65) or nab-P/G (n = 45) as first-line chemotherapy between November 2013 and June 2019 were reviewed.

Results

The objective response rate (ORR) and disease control rate were numerically higher with nab-P/S than with nab-P/G (38.5% vs 28.9%, P = 0.30, 73.8% vs 66.7%, P = 0.42, respectively). ORRs of the primary lesion were similar for both groups (30.8% and 22.2%, P = 0.32). The median progression-free survival and overall survival were comparable between the two groups (5.5 vs 5.7 months, P = 0.34, 10.2 vs 11.3 months, P = 0.74, respectively). Nab-P/S was associated with a numerically lower risk of adverse events, especially hematologic adverse events.

Conclusion

Nab-P/S could be a convenient alternative with similar efficacy and a favorable safety profile compared with nab-P/G as first-line chemotherapy for advanced PDAC, as well as an option for neoadjuvant therapy.

Toward Bridging Microexpressions From Different Domains

Recently, microexpression recognition has attracted a lot of researchers' attention due to its challenges and valuable applications. However, it is noticed that currently most of the existing proposed methods are often evaluated and tested on the single database and, hence, this brings us a question whether these methods are still effective if the training and testing samples belong to different domains, for example, different microexpression databases. In this case, a large feature distribution difference may exist between training (source) and testing (target) samples and, hence, microexpression recognition tasks would become more difficult. To solve this challenging problem, that is, cross-domain microexpression recognition, in this paper, we propose an effective method consisting of an auxiliary set selection model (ASSM) and a transductive transfer regression model (TTRM). In our method, an ASSM is designed to automatically select an optimal set of samples from the target domain to serve as the auxiliary set, which is used for subsequent TTRM training. As for TTRM, it aims at bridging the feature distribution gap between the source and target domains by learning a joint regression model with the source domain samples and the auxiliary set selected from the target domain. We evaluate the proposed TTRM plus ASSM by extensive cross-domain microexpression recognition experiments on SMIC and CASME II databases. Compared with the recent state-of-the-art domain adaptation methods, our proposed method has a more satisfactory performance in dealing with the cross-domain microexpression recognition tasks.

Feasibility of microscope-integrated swept-source optical coherence tomography in canaloplasty

Background

Several researchers have used commercial microscope-integrated optical coherence tomography (OCT) systems in glaucoma surgery, including ab interno trabeculectomy and canaloplasty. However, the 840 nm wavelength light source of the OCT systems is not ideal for imaging the anterior chamber angle structures because of its limited penetration. We evaluated the potential value of a microscope-integrated swept-source OCT system with a 1,310 nm center-wavelength light in canaloplasty for glaucoma.

Methods

Sixteen porcine eyes were used to simulate canaloplasty. The critical surgical steps were monitored using a prototype microscope-integrated OCT system with a 1,310 nm light source and a high axial scan rate of 100 kHz. The images from swept-source OCT and three-dimensional images from the microscope were projected simultaneously onto a liquid crystal display three-dimensional monitor (LMD-4251TD, Sony, Japan). The changes in the collector vessel (aqueous drainage structure in the porcine eye, similar to Schlemm’s canal in humans) were measured using Image J software. Histological sections stained with hematoxylin and eosin were used to assess surgical efficacy.

Results

High-resolution real-time images of the anterior segment were acquired during canaloplasty using the microscope-integrated OCT system. With the real-time OCT images, the position of the collector vessel was identified and the scleral flap could be created at the ideal location. The expansion of the collector vessel after viscoelastic injection was also visualized in real time. Compared with baseline, there was a significant increase in the cross-sectional area (from 14,502.98±9,242.55 to 59,499.04±20,506.41 µm², P<0.001) of the collector vessel.

Conclusions

Using the microscope-integrated OCT system, real-time images of the anterior segment were successfully acquired during the operation. The microscope-integrated OCT system might be useful in future anti-glaucoma surgery.

Automatic Identification of High-Risk Autism Spectrum Disorder: A Feasibility Study Using Video and Audio Data Under the Still-Face Paradigm

It is reported that the symptoms of autism spectrum disorder (ASD) could be improved by effective early interventions, which arouses an urgent need for large-scale early identification of ASD. Until now, the screening of ASD has relied on the child psychiatrist to collect medical history and conduct behavioral observations with the help of psychological assessment tools. Such screening measures inevitably have some disadvantages, including strong subjectivity, relying on experts and low-efficiency. With the development of computer science, it is possible to realize a computer-aided screening for ASD and alleviate the disadvantages of manual evaluation. In this study, we propose a behavior-based automated screening method to identify high-risk ASD (HR-ASD) for babies aged 8-24 months. The still-face paradigm (SFP) was used to elicit baby's spontaneous social behavior through a face-to-face interaction, in which a mother was required to maintain a normal interaction to amuse her baby for 2 minutes (a baseline episode) and then suddenly change to the no-reaction and no-expression status with 1 minute (a still-face episode). Here, multiple cues derived from baby's social stress response behavior during the latter episode, including head-movements, facial expressions and vocal characteristics, were statistically analyzed between HR-ASD and typical developmental (TD) groups. An automated identification model of HR-ASD was constructed based on these multi-cue features and the support vector machine (SVM) classifier; moreover, its screening performance was satisfied, for all the accuracy, specificity and sensitivity exceeded 90% on the cases included in this study. The experimental results suggest its feasibility in the early screening of HR-ASD.

The Clinical Features and Genetic Spectrum of a Large Cohort of Chinese Patients With Vitelliform Macular Dystrophies

PURPOSE

To provide the clinical and genetic characteristics of a large cohort of Chinese patients with vitelliform macular dystrophies.

DESIGN

Cross-sectional study.

METHODS

One hundred and thirty-four unrelated Chinese patients diagnosed with Best vitelliform macular dystrophy (BVMD), autosomal recessive bestrophinopathy (ARB), or adult vitelliform macular dystrophy (AVMD) were enrolled. Detailed ophthalmic examinations and genetic testing on vitelliform macular dystrophy-related genes were performed. Genotype and phenotype association were analyzed among different diagnostic groups.

RESULTS

In total, 87 BVMD, 30 AVMD, and 17 ARB patients were enrolled in this study. Genetic analysis identified 37 BEST1 mutations in 53 patients with BVMD and ARB. Of these, 5 variants (c.254A>C, c.291C>G, c.722C>G, c.848_850del, c.1740-2A>C) were novel. The variant c.898G>A was a hotspot mutation, which was identified in 13 patients with BVMD and 1 patient with ARB. There were significant differences of ocular biometric parameters among patients with homozygous or compound heterozygous mutations, heterozygous mutations, and those without mutations of BEST1. Homozygous or compound heterozygous patients had shortest axial length (AL), shallowest anterior chamber depth (ACD), and highest intraocular pressure (IOP); patients without mutations had longest AL, deepest ACD, and lowest IOP; and heterozygous patients were in between. Moreover, 7 patients harboring heterozygous mutations in BEST1 and 3 patients without BEST1 mutations showed similar clinical appearance to ARB in our cohort.

CONCLUSIONS

This is the largest sample size study of Chinese vitelliform macular dystrophy patients. Our results indicated that assessment of angle-closure risk is a necessary consideration for all types of BEST1-related vitelliform macular dystrophies. The study expanded both the clinical and genetic findings of 3 common types of vitelliform macular dystrophies in a Chinese population.

Targeted, random mutagenesis of plant genes with dual cytosine and adenine base editors

Targeted saturation mutagenesis of crop genes could be applied to produce genetic variants with improved agronomic performance. However, tools for directed evolution of plant genes, such as error-prone PCR or DNA shuffling, are limited1. We engineered five saturated targeted endogenous mutagenesis editors (STEMEs) that can generate de novo mutations and facilitate directed evolution of plant genes. In rice protoplasts, STEME-1 edited cytosine and adenine at the same target site with C > T efficiency up to 61.61% and simultaneous C > T and A > G efficiency up to 15.10%. STEME-NG, which incorporates the nickase Cas9-NG protospacer-adjacent motif variant, was used with 20 individual single guide RNAs in rice protoplasts to produce near-saturated mutagenesis (73.21%) for a 56-amino-acid portion of the rice acetyl-coenzyme A carboxylase (OsACC). We also applied STEME-1 and STEME-NG for directed evolution of the OsACC gene in rice and obtained herbicide resistance mutations. This set of two STEMEs will accelerate trait development and should work in any plants amenable to CRISPR-based editing.

Precise, predictable multi-nucleotide deletions in rice and wheat using APOBEC-Cas9

Short insertions and deletions can be produced in plant genomes using CRISPR-Cas editors, but reliable production of larger deletions in specific target sites has proven difficult to achieve. We report the development of a series of APOBEC-Cas9 fusion-induced deletion systems (AFIDs) that combine Cas9 with human APOBEC3A (A3A), uracil DNA-glucosidase and apurinic or apyrimidinic site lyase. In rice and wheat, AFID-3 generated deletions from 5'-deaminated C bases to the Cas9-cleavage site. Approximately one-third of deletions produced using AFID-3 in rice and wheat protoplasts (30.2%) and regenerated plants (34.8%) were predictable. We show that eAFID-3, in which the A3A in AFID-3 is replaced with truncated APOBEC3B (A3Bctd), produced more uniform deletions from the preferred TC motif to the double-strand break. AFIDs could be applied to study regulatory regions and protein domains to improve crop plants.

SWISS: multiplexed orthogonal genome editing in plants with a Cas9 nickase and engineered CRISPR RNA scaffolds

We describe here a CRISPR simultaneous and wide-editing induced by a single system (SWISS), in which RNA aptamers engineered in crRNA scaffold recruit their cognate binding proteins fused with cytidine deaminase and adenosine deaminase to Cas9 nickase target sites to generate multiplexed base editing. By using paired sgRNAs, SWISS can produce insertions/deletions in addition to base editing. Rice mutants are generated using the SWISS system with efficiencies of cytosine conversion of 25.5%, adenine conversion of 16.4%, indels of 52.7%, and simultaneous triple mutations of 7.3%. The SWISS system provides a powerful tool for multi-functional genome editing in plants.

Microscope-integrated Intraoperative Optical Coherence Tomography for Anterior Segment Surgical Maneuvers

Purpose

To evaluate the potential value of microscope-integrated optical coherence tomography (MI-OCT) in anterior segment surgical maneuvers.

Methods

Twenty-four ophthalmology residents, who were randomly and evenly divided into two groups, performed four anterior segment surgical maneuvers (corneal tunnel, scleral tunnel, simple corneal suture, and corneal laceration repair) on porcine eyes with (group B) or without (group A) real-time MI-OCT feedback. All residents performed the maneuvers again without MI-OCT.

Results

Compared with group A, group B (with MI-OCT) showed better accuracy in the length/depth of the corneal tunnel and the length of the scleral tunnel. However, both groups showed similar performances in the depth of both the simple corneal suture and the corneal laceration suture. When both groups performed the maneuvers again without MI-OCT, group B still showed better results than group A for the length of both the corneal and scleral tunnels.

Conclusions

Primary results suggest that real-time MI-OCT images are valuable for some anterior segment surgical maneuvers and could be helpful in surgical training.

Translational Relevance

MI-OCT systems can be valuable in improving accuracy and decision making during anterior segment surgery and will be useful in surgical training.

Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L

BACKGROUND

Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke). Usually, purple tubers with high anthocyanin content are more nutritious than white tuber. But, the molecular mechanism underlying it is unknown.

RESULTS

In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Compared with the white-skinned tubers of cultivar QY3, anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in 'QY1'; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor, homologous to the MYB transcription factor regulating anthocyanin biosynthesis, expressed in the red tuber epidermis of 'QY1'. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of 'QY1' was higher than in 'QY3', especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of 'QY1' than in 'QY3'. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in 'QY1' and 'QY3', but that there were several single nucleotide polymorphisms and one insertion-deletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides "AAA" made the promoter of 'QY1' predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population.

CONCLUSIONS

RNA-seq can successfully isolate the candidate gene (HTMYB2) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

A fructan: the fructan 1-fructosyl-transferase gene from Helianthus tuberosus increased the PEG-simulated drought stress tolerance of tobacco

BACKGROUND

Jerusalem artichoke (Helianthus tuberosus) is a fructan-accumulating plant, and an industrial source of raw material for fructan production, but the crucial enzymes involved in fructan biosynthesis remain poorly understood in this plant.

RESULTS

In this study, a fructan: fructan 1-fructosyl-transferase (1-FFT) gene, Ht1-FFT, was isolated from Jerusalem artichoke. The coding sequence of Ht1-FFT was 2025 bp in length, encoding 641 amino acids. Ht1-FFT had the type domain of the 1-FFT protein family, to which it belonged, according to phylogenetic tree analysis, which implied that Ht1-FFT had the function of catalyzing the formation and extension of beta-(2,1)-linked fructans. Overexpression of Ht1-FFT in the leaves of transgenic tobacco increased fructan concentration. Moreover, the soluble sugar and proline concentrations increased, and the malondialdehyde (MDA) concentration was reduced in the transgenic lines. The changes in these parameters were associated with increased stress tolerance exhibited by the transgenic tobacco plants. A PEG-simulated drought stress experiment confirmed that the transgenic lines exhibited increased PEG-simulated drought stress tolerance.

CONCLUSIONS

The 1-FFT gene from Helianthus tuberosus was a functional fructan: fructan 1-fructosyl-transferase and played a positive role in PEG-simulated drought stress tolerance. This transgene could be used to increase fructan concentration and PEG-simulated drought stress tolerance in plants by genetic transformation.

Prime genome editing in rice and wheat

Prime editors, which are CRISPR-Cas9 nickase (H840A)-reverse transcriptase fusions programmed with prime editing guide RNAs (pegRNAs), can edit bases in mammalian cells without donor DNA or double-strand breaks. We adapted prime editors for use in plants through codon, promoter, and editing-condition optimization. The resulting suite of plant prime editors enable point mutations, insertions and deletions in rice and wheat protoplasts. Regenerated prime-edited rice plants were obtained at frequencies of up to 21.8%.

Efficacy and safety of nab-paclitaxel plus S-1(nab-P/S-1) versus nab-paclitaxel plus gemcitabine (nab-P/Gem) for first-line chemotherapy in advanced pancreatic ductal adenocarcinoma (aPDAC): A randomized study

717

Background: Nab-P/Gem significantly improved survival compared with gem in patients (pts) with metastatic PDAC, but the ORR was limited to 23% with increased myelosuppression. Two phase II trials demonstrated high ORR of 50.0-53.1% with nab-P/S-1 and showed less hematologic toxicity. Methods: A randomized (1:1) phase II trial was conducted. Eligibility required treatment-naïve pts with unresectable PDAC. Pts received nab-P 125mg/m2on day 1 + S-1 80-120mg orally per day on day 1-7 every 2 weeks or nab-P 125mg/m2+ Gem 1000mg/m2 on days 1,8 every 3 weeks. With an increase of ORR from 25% to 50%, 100 pts were required for 90% power at a two-sided significance level of 0.05. We enrolled 40 pts for a pilot study. Primary endpoints were ORR and 6-month PFS rate. Secondary endpoints were ORR of primary lesion, DCR, PFS, OS and safety. Results: 40 pts were enrolled between 06/2018 and 06/2019, including locally advanced (27.5%) and metastatic (72.5%) PDACs. 42.5% were male and the median age was 61 (range, 36-75) years old. The median duration of treatment was 2.3 months in nab-P/S-1 (n = 20) and 2.7 months in nab-P/Gem (n = 20). In the intention-to-treat (ITT) population, the ORR and DCR were 35.0% vs 25.0% ( P= 0.49) and 70.0% vs 70.0%, respectively.The ORR of primary lesion was 30.0% vs 25.0% ( P= 0.72). In the evaluable pts (nab-P/S-1 n = 18, nab-P/Gem n = 18), the ORR, DCR and the ORR of primary lesion were 38.9% vs 27.8%, 77.8% vs 77.8% and 35.3% vs 29.4%, respectively.With the median follow-up of 5.0 (range 0.3-11.4) months, the median PFS and 6-month PFS rate was 6.3 vs 5.7 months and 56.1% vs 36.2%( P= 0.61) for nab-P/S-1 and nab-P/Gem, respectively. The median OS have not reached. Grade 3/4 toxicities occurred in 30.0% nab-P/S-1 and 30.0% nab-P/Gem: leukopenia/neutropenia(15.0% vs 25.0%), febrile neutropenia (0 vs 5.0%), rash (0 vs 5.0%) and diarrhea (10.0% vs 0). Conclusions: Compared with nab-P/Gem, nab-P/S-1 had higher ORR, ORR of primary lesion and longer PFS without significant difference. Nab-P/S-1 developed a trend towards less hematologic toxicity. Follow up for survival is ongoing. Clinical trial information: 03636308.

Measurement of the depths at different regions of the anterior chamber in healthy Chinese adults

AIM

To measure the depths of different regions of the anterior chamber (AC) in healthy Chinese adults, and to explore possible correlations with age or gender.

METHODS

The AC was imaged by swept-source optical coherence tomography in healthy Chinese adults. The horizontal scan of the right eye was used to measure the anterior chamber depth (ACD) at 199 points.

RESULTS

A total of 309 images from 309 subjects were analyzed. The ACD values at nearly all locations were negatively correlated with age (all P<0.05), except for ACD1, 2, 198, and 199 (correspond to the iris roots). The mean annual decrease 0.013±0.005 mm/y for all ACDs combined, 0.008±0.004 mm/y for the peripheral region, 0.017±0.003 mm/y for the middle peripheral region, and 0.014±0.001 mm/y for the central region. The mean annual decrease was significantly different among these three regions (P<0.001). The ACD was greater in males than in females (P<0.05). The mean difference in ACD between males and females was 0.081±0.025 mm.

CONCLUSION

This study showed that optical coherence tomography can be used to measure the ACD of different regions of the AC. We found reductions in ACD with age, although the reduction varied among different points, in healthy Chinese adults.

Overexpression of ThMYC4E Enhances Anthocyanin Biosynthesis in Common Wheat

The basic helix-loop helix (bHLH) transcription factor has been inferred to play an important role in blue and purple grain traits in common wheat, but to date, its overexpression has not been reported. In this study, the bHLH transcription factor ThMYC4E, the candidate gene controlling the blue grain trait from Th. Ponticum, was transferred to the common wheat JW1. The positive transgenic lines displayed higher levels of purple anthocyanin pigments in their grains, leaves and glumes. Stripping the glumes (light treatment) caused white grains to become purple in transgenic lines. RNA-Seq and qRT-PCR analysis demonstrated that the transcript levels of structural genes associated with anthocyanin biosynthesis were higher in transgenic wheat than the wild-type (WT), which indicated that ThMYC4E activated anthocyanin biosynthesis in the transgenic lines. Correspondingly, the anthocyanin contents in grains, roots, stems, leaves and glumes of transgenic lines were higher than those in the WT. Metabolome analysis demonstrated that the anthocyanins were composed of cyanidin and delphinidin in the grains of the transgenic lines. Moreover, the transgenic lines showed higher antioxidant activity, in terms of scavenging DPPH radicals, in the ethanol extracts of their grains. The overexpression of ThMYC4E sheds light on the traits related to anthocyanin biosynthesis in common wheat and provide a new way to improve anthocyanin content.

Comprehensive Influences of Overexpression of a MYB Transcriptor Regulating Anthocyanin Biosynthesis on Transcriptome and Metabolome of Tobacco Leaves

Overexpression of R2R3-MYB transcriptor can induce up-expression of anthocyanin biosynthesis structural genes, and improve the anthocyanin content in plant tissues, but it is not clear whether the MYB transcription factor overexpression does effect on other genes transcript and chemical compounds accumulation. In this manuscript, RNA-sequencing and the stepwise multiple ion monitoring-enhanced product ions (stepwise MIM-EPI) strategy were employed to evaluate the comprehensive effect of the MYB transcription factor LrAN2 in tobacco. Overexpression of LrAN2 could promote anthocyanin accumulation in a lot of tissues of tobacco cultivar Samsun. Only 185 unigenes express differently in a total of 160,965 unigenes in leaves, and 224 chemical compounds were differently accumulated. Three anthocyanins, apigeninidin chloride, pelargonidin 3-O-beta-D-glucoside and cyanidin 3,5-O-diglucoside, were detected only in transgenic lines, which could explain the phenotype of purple leaves. Except for anthocyanins, the phenylpropanoid, polyphenol (catechin), flavonoid, flavone and flavonol, belong to the same subgroups of flavonoids biosynthesis pathway with anthocyanin and were also up-accumulated. Overexpression of LrAN2 activated the bHLH (basic helix-loop-helix protein) transcription factor AN1b, relative to anthocyanin biosynthesis and the MYB transcription factor MYB3, relative to proanthocyanin biosynthesis. Then, the structural genes, relative to the phenylpropanoid pathway, were activated, which led to the up-accumulation of phenylpropanoid, polyphenol (catechin), flavonoid, flavone, flavonol and anthocyanin. The MYB transcription factor CPC, negative to anthocyanin biosynthesis, also induced up-expression in transgenic lines, which implied that a negative regulation mechanism existed in the anthocyanin biosynthesis pathway. The relative contents of all 19 differently accumulated amino and derivers were decreased in transgenic lines, which meant the phenylalanine biosynthesis pathway completed the same substrates with other amino acids. Interestingly, the acetylalkylglycerol acetylhydrolase was down-expressed in transgenic lines, which caused 19 lyso-phosphatidylcholine and derivatives of lipids to be up-accumulated, and 8 octodecane and derivatives were down-accumulated. This research will give more information about the function of MYB transcription factors on the anthocyanin biosynthesis and other chemical compounds and be of benefit to obtaining new plant cultivars with high anthocyanin content by biotechnology.

A bHLH transcription factor TsMYC2 is associated with the blue grain character in triticale (Triticum × Secale)

RNA-Seq was employed to compare the transcriptome differences between the triticale lines and to identify the key gene responsible for the blue aleurone trait. The accumulation of anthocyanins in the aleurone of triticale results in the formation of the blue-grained trait, but the identity of the genes associated with anthocyanin biosynthesis in the aleurone has not yet been reported. In this manuscript, RNA-Seq was employed to compare the transcriptome differences between the triticale lines HM13 (blue aleurone) and HM5 (white aleurone), and to identify the key genes responsible for the blue aleurone trait. There were 32,406 differentially expressed genes between HM13 and HM5. Seventy-three unigenes were homologous to the structural genes related to anthocyanin biosynthesis, and the average transcript level of the structural genes was higher in HM13 than in HM5, so that quantitative differences between the two lines in transcription rates could be the cause of the blue aleurone. The MYB and bHLH transcription factors had two homologous unigenes, but contained only one differentially expressed unigene each. The relative transcript level of bHLH Unigene5672_All (TsMYC2) in HM13 was 42.71 times that in HM5, while the relative transcript level of the MYB transcription factor Unigene12228_All in HM13 was 2.20 times that in HM5. qPCR experiments determined the relative transcript level of TsMYC2 in developing grain, with the expression of TsMYC2 in grain being the highest compared with that in root, stem or leaf tissue. TsMYC2 was homologous to the bHLH transcription factor regulating anthocyanin biosynthesis and contained three entire functional domains: bHLH-MYC_N, HLH and ACT-like, which were important for exercising regulation of anthocyanin biosynthesis as a bHLH transcription factor. Transient expression of ZmC1 and TsMYC2 could induce anthocyanin biosynthesis in white wheat coleoptile cells, demonstrating that TsMYC2 was a functional bHLH transcription factor. These results indicated that TsMYC2 was associated with the blue aleurone trait and could prove to be a valuable gene with which to breed new triticale cultivars with the blue aleurone trait.

[Progress on base editing systems]

Base editing is a newly developed precise genome editing technique based on the CRISPR/Cas system. According to different base modification enzymes, the current base editing systems can be divided into cytosine base editors (CBE) and adenine base editors (ABE). They use cytosine deaminases or artificially evolved adenine deaminases to perform single-base editing, and achieve C to T (G to A) or A to G (T to C) substitutions, respectively. Due to high efficiency, independence of DNA double-strand breaks, and no need for donor DNA, base editing systems have been successfully applied in diverse species including animals, plants and other organisms since the first report in 2016. Therefore, base editing systems will have a high prospect of providing important support for gene therapy and crop genetic improvement in the future. In this review, we describe the development and current applications of base editing systems for basic research and biotechnology, highlight the challenges, and discuss the directions for future research in this important field. The information presented may facilitate interested researchers to grasp the principles of base editing, to use relevant base editing tools in their own studies, or to innovate new versions of base editing in the future.

Automatic Classification of Anterior Chamber Angle Using Ultrasound Biomicroscopy and Deep Learning

Purpose

To develop a software package for automated classification of anterior chamber angle of the eye by using ultrasound biomicroscopy.

Methods

Ultrasound biomicroscopy images were collected, and the trabecular-iris angle was manually measured and classified into three categories: open angle, narrow angle, and angle closure. Inception v3 was used as the classifying convolutional neural network and the algorithm was trained.

Results

With a recall rate of 97% in the test set, the neural network's classification accuracy can reach 97.2% and the overall area under the curve was 0.988. The sensitivity and specificity were 98.04% and 99.09% for the open angle, 96.30% and 98.13% for the narrow angle, and 98.21% and 99.05% for the angle closure categories, respectively.

Conclusions

Preliminary results show that an automated classification of the anterior chamber angle achieved satisfying sensitivity and specificity and could be helpful in clinical practice.

Translational Relevance

The present work suggests that the algorithm described here could be useful in the categorizing of anterior chamber angle and screening for subjects who are at high risk of angle closure.

Nab-paclitaxel/S-1(AS) versus nab-paclitaxel/gemcitabine(AG) for first-line chemotherapy in advanced pancreatic ductal adenocarcinoma (aPDAC): A retrospective analysis of efficacy and safety

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Background: AG significantly improved PFS and OS compared with gemcitabine monotherapy in patients (pts) with metastatic PDAC, but the confirmed ORR was limited to 23% with increased grade 3 or 4 myelosuppression. In GEST and JASPAC01 studies, S-1 showed non-inferior or superior activity to gemcitabine in advanced and postoperative PDAC. S-1 also developed less hematologic adverse events especially in neutropenia and was a convenient oral alternative. Two single-arm phase II trials in China demonstrated high ORR of 50.0-53.1% with AS. We investigated the efficacy and safety of first-line chemotherapy with AS versus AG in pts with aPDAC. Methods: A retrospective review was conducted of aPDAC pts treated with first-line AS and AG in GI dpt. Of PUCH between 11/2013 and 12/2018. Pts received 125mg/m2 nab-paclitaxel intravenously (IV) on day1, and 80-100mg S-1 orally per day on day1-7 every two weeks in AS cohort, while pts received 125mg/m2 nab-paclitaxel IV on day1,8, and 1000mg/m2 gemcitabine IV on day1,8 every three weeks in AG cohort. ORR, ORR of primary lesion, DCR, PFS, OS and safety were analysed between two cohorts. Survival outcomes were evaluated by Kaplan-Meier method and compared with the log-rank test. A Cox proportional hazard model was made to determine independent predictors of survival. Results: A total of 70 pts (45 in AS cohort, 25 in AG cohort) with locally advanced (4%) and metastatic (96%) PDACs were identified. 75% were male and the median age was 65(range 36-72). Among intention-to-treat population, the ORR and DCR were 40.0% vs 32.0% (p = 0.70) and 75.6% vs 64.0% (p = 0.57) in AS and AG cohort, respectively. The ORR of primary lesion was 31.1% with AS vs 20.0% with AG (p = 0.73). With the median follow-up of 9.8 months(range 2.3-22.2), the median PFS and OS were 4.7m vs 6.7m (HR, 1.2; 95% CI, 0.6 to 2.4; p = 0.62) and 10.3m vs 11.3m (HR, 0.9; 95% CI, 0.5 to 1.8; p = 0.78) in AS and AG cohort, respectively. Grade 3/4 toxicities occurred in 31.1% AS vs 36.0% AG (p = 0.59). Most G3/4 toxicities were: leukopenia/neutropenia (26.7% vs 20.0%), febrile neutropenia (2.2% vs 8.0%), thrombocytopenia (0 vs 12%), fatigue (4.4% vs 12%), peripheral neuropathy (0 vs 8.0%). In multivariate analysis, liver metastasis was the only independent predictor of poor OS (HR 0.3, 95%CI 0.1-0.8, p = 0.014). Conclusions: AS was a comparable and convenient alternative with manageable toxicities in aPDAC. There was a trend towards improved ORR of primary lesion compared with AG.