Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution

BACKGROUND

Macrolactins, a type of macrolide antibiotic, are toxic to the producer strains. As such, its level is usually maintained below the lethal concentration during the fermentation process. To improve the production of macrolactins, we applied adaptive laboratory evolution technology to engineer a saline-resistant mutant strain. The hypothesis that strains with saline resistance show improved macrolactins production was investigated.

RESULTS

Using saline stress as a selective pressure, we engineered a mutant strain with saline resistance coupled with enhanced macrolactins production within 60 days using a self-made device. As compared with the parental strain, the evolved strain produced macrolactins with 11.93% improvement in non-saline stress fermentation medium containing 50 g/L glucose, when the glucose concentration increased to 70 g/L, the evolved strain produced macrolactins with 71.04% improvement. RNA sequencing and metabolomics results revealed that amino acid metabolism was involved in the production of macrolactins in the evolved strain. Furthermore, genome sequencing of the evolved strain revealed a candidate mutation, hisD^D41Y, that was causal for the improved MLNs production, it was 3.42 times higher than the control in the overexpression hisD^D41Y strain. Results revealed that saline resistance protected the producer strain from feedback inhibition of end-product (macrolide antibiotic), resulting in enhanced MLNs production.

CONCLUSIONS

In the present work, we successfully engineered a mutant strain with enhanced macrolactins production by adaptive laboratory evolution using saline stress as a selective pressure. Based on physiological, transcriptomic and genetic analysis, amino acid metabolism was found to benefit macrolactins production improvement. Our strategy might be applicable to improve the production of other kinds of macrolide antibiotics and other toxic compounds. The identification of the hisD mutation will allow for the deduction of metabolic engineering strategies in future research.

Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score

Background

Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score.

Methods

This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally.

Results

Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification.

Conclusion

The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy.

Isolation, Screening, and Active Metabolites Identification of Anti-Vibrio Fungal Strains Derived From the Beibu Gulf Coral

The Beibu Gulf harbors abundant underexplored marine microbial resources, which are rich in diversified secondary metabolites. The genera Vibrio is a well-known pathogenic bacterium of aquatic animals. In this study, 22 fungal strains were isolated and identified from the Beibu Gulf coral via the serial dilution method and internal transcribed spacer (ITS) sequence analysis, which were further divided into three branches by phylogenetic tree analysis. The crude extracts of them via small-scale fermentation were selected for the screening of inhibitory activity against Vibrio alginalyticus, Vibrio coralliilyticus, Vibrio harveyi, Vibrio parahaemolyticus, Vibrio owensii, and Vibrio shilonii. The results showed that eight fungal extracts displayed anti-Vibrio activity via the filter paper disk assay. Several of them showed strong inhibitory effects. Then, two tetramic acid alkaloids, equisetin (1) and 5'-epiequisetin (2), were identified from Fusarium equiseti BBG10 by bioassay-guided isolation, both of which inhibited the growth of Vibrio spp. with the MIC values of 86-132 μg/ml. The scanning electron microscope results showed that cell membranes of Vibrio became corrugated, distorted or ruptured after treatment with 1 and 2. Taken together, this study provided eight fungal isolates with anti-Vibrio potentials, and two alkaloid-type antibiotics were found with anti-Vibrio effects from the bioactive strain F. equiseti BBG10. Our findings highlight the importance of exploring promising microbes from the Beibu Gulf for the identification of anti-Vibrio for future antibiotic development.

End-to-End Full Projector Compensation

Full projector compensation aims to modify a projector input image to compensate for both geometric and photometric disturbance of the projection surface. Traditional methods usually solve the two parts separately and may suffer from suboptimal solutions. In this paper, we propose the first end-to-end differentiable solution, named CompenNeSt++, to solve the two problems jointly. First, we propose a novel geometric correction subnet, named WarpingNet, which is designed with a cascaded coarse-to-fine structure to learn the sampling grid directly from sampling images. Second, we propose a novel photometric compensation subnet, named CompenNeSt, which is designed with a siamese architecture to capture the photometric interactions between the projection surface and the projected images, and to use such information to compensate the geometrically corrected images. By concatenating WarpingNet with CompenNeSt, CompenNeSt++ accomplishes full projector compensation and is end-to-end trainable. Third, to improve practicability, we propose a novel synthetic data-based pre-training strategy to significantly reduce the number of training images and training time. Moreover, we construct the first setup-independent full compensation benchmark to facilitate future studies. In thorough experiments, our method shows clear advantages over prior art with promising compensation quality and meanwhile being practically convenient.

POS0739 THE RENAL ACTIVITY INDEX FOR LUPUS (RAIL) DIFFERENTIATES ACTIVE AND INACTIVE NEPHRITIS IN ADULT PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background

Lupus nephritis (LN) confers a poor prognosis, with lack of effective laboratory tests to diagnose and evaluate therapies. We have demonstrated that the RAIL score, based on a set of six urinary biomarkers (NGAL, KIM-1, MCP-1, adiponectin, hemopexin, ceruloplasmin) is sensitive and specific in adult patients with active LN, using renal biopsy as reference.1,2 RAIL has been shown in the pediatric population to be effective in distinguishing inactive vs active LN with no effect from mycophenolate mofetil (MMF) treatment. A comparable study has not been conducted in an adult population.

Objectives

To assess the ability of RAIL to discriminate patients with active LN vs active non-renal SLE and to evaluate if RAIL performance varies by MMF treatment using urine samples from adult LN patients.

Methods

Urine samples were obtained at baseline in two clinical trials: a phase 2 study in adult patients with biopsy-proven active Class III and IV LN (NCT02547922) and a subset of patients from the phase 3 trial in adults with active non-renal SLE (NCT02446912) who had baseline renal BILAG scores C, D, or E. RAIL biomarkers were assayed using single-plex assays. Patient demographics and clinical characteristics were compared between studies. Wilcoxon rank sum test was performed comparing the urinary biomarkers between the two studies and RAIL score was then calculated. Receiver operating characteristic (ROC) analyses were conducted assessing the ability for RAIL scores to distinguish patients with renal activity and involvement.

Results

Comparison of the patient demographic, clinical characteristics, and biomarkers is in the Table 1. Wilcoxon rank sum test showed the six urinary biomarkers were significantly different between two groups of patients as demonstrated (Table 1). Each of the RAIL biomarker concentrations and the creatinine-adjusted median score were higher in the active LN group than the SLE group (P<0.001). ROC analyses including RAIL score showed an area under the ROC curve of 0.8 (Figure 1), with odds ratio of log-transformed RAIL 2.027 (95% CI [1.587, 2.589]). There were no significant interactions between RAIL and MMF. RAIL remained significant after adjusting for estimated glomerular filtration rate (eGFR), which was not statistically significant.

Table 1.

Study Demographics and Biomarkers

VariablesLN study (N=131)SLE study (N=59)Observed NObserved Median (IQR) or %Observed NObserved Median (IQR) or %DemographicsAge13134 (25, 42)5936 (28, 44)Sex, Female10983.21%5593.22%Race, White5642.75%4576.27%Ethnicity, Hispanic or Latino6146.56%915.25%OCS use, yes12797.69%5796.61%MMF use, yes9572.52%2135.59%Spot UPCR (mg/mg)1282.13 (1.22, 4.04)591.11 (0.55, 2.61)eGFR13091.8 (63.1, 125)5998.06 (81.91, 116.54)Non-renal SLEDAI-2K score1304 (4, 6)5912 (9, 13)Renal SLEDAI-2K score1304 (4, 8)590 (0, 0)BiomarkersNGAL (ng/mL)12833.33 (17.55, 56.7)5819.47 (11.37, 42.05)MCP-1 (pg/mL)128658.24 (271.58, 1049.95)58275.62 (106.09, 481.99)Ceruloplasmin (ng/mL)12893.55 (44.5, 311.25)5847.2 (13.05, 231.25)Adiponectin (ng/mL)12842.45 (16.71, 139.64)589.33 (3.35, 25.51)Hemopexin (ng/mL)1281876.8 (745.07, 4743.4)58513.4 (236.36, 1388.74)KIM-1 (pg/mL)1281673.5 (772.5, 2767)58864 (394, 1480)Creatinine (mg/mL)1280.7 (0.46, 1.3)580.99 (0.46, 1.74)Adult RAIL score (creatinine adjusted)1285.59 (4.31, 6.47)583.57 (2.78, 4.47)

eGFR, estimated glomerular filtration rate; IQR, interquartile range; KIM, kidney injury molecule; LN, lupus nephritis; MCP, monocyte chemotactic protein; MMF, mycophenolate mofetil; NGAL, neutrophil gelatinase-associated lipocalin; OCS, oral corticosteroid; SLEDAI-2K, SLE Disease Activity Index 2000; UPCR, urine protein/creatinine ratio.

Conclusion

The analyses performed suggest that creatinine-corrected RAIL discriminates between active LN and non-renal adult SLE, with RAIL scores not influenced by MMF use.

References

[1]Brunner HI. Arthritis Care Res (Hoboken). 2016;68:1003–11.

[2]Gulati G. Lupus. 2017;26:927–36.

Acknowledgements

Writing assistance by Kelly M. Hunter, PhD (Fishawack). This study was sponsored by AstraZeneca.

Disclosure of Interests

Ellen Cody: None declared, Hermine Brunner Speakers bureau: Novartis, Pfizer, GSK, Consultant of: AbbVie, Astra Zeneca-Medimmune, Biogen, Boehringer, Bristol Myers Squibb, Celgene, Lilly,EMD Serono, Idorsia, Cerocor, Janssen, GSK, F. Hoffmann-La Roche, Merck, Novartis, R-Pharm, Sanofi, Grant/research support from: Pfizer, Bin Huang: None declared, Tingting Qiu: None declared, Prasad Devarajan Speakers bureau: Reata, Alnylam, Dicerna, Consultant of: BioPorto Inc, Madhu Ramaswamy Shareholder of: AstraZeneca, Employee of: AstraZeneca, Dominic Sinibaldi Shareholder of: AstraZeneca, Employee of: AstraZeneca, Philip Z Brohawn Shareholder of: AstraZeneca, Employee of: AstraZeneca, Jacob Knagenhjelm Shareholder of: AstraZeneca, Employee of: AstraZeneca, Frederick Jones Shareholder of: AstraZeneca, Employee of: AstraZeneca, Raj Tummala Shareholder of: AstraZeneca, Employee of: AstraZeneca, Catharina Lindholm Employee of: AstraZeneca, Wendy White Shareholder of: AstraZeneca, Employee of: AstraZeneca

Anti-Osteoclastogenic and Antibacterial Effects of Chlorinated Polyketides from the Beibu Gulf Coral-Derived Fungus Aspergillus unguis GXIMD 02505

One new depsidone derivative, aspergillusidone H (3), along with seven known biosynthetically related chlorinated polyketides, were obtained from the Beibu Gulf coral-derived fungus Aspergillus unguis GXIMD 02505. Their structures were determined by comprehensive physicochemical and spectroscopic data interpretation. Notably, the X-ray crystal structure of 2 and the previously unknown absolute configuration of 8, assigned by ECD calculations, are described here for the first time. Compounds 1–5, 7 and 8 exhibited inhibition of lipopolysaccharide (LPS)-induced NF-κB in RAW 264.7 macrophages at 20 μM. In addition, the two potent inhibitors (2 and 7) dose-dependently suppressed RANKL-induced osteoclast differentiation without any evidence of cytotoxicity in bone marrow macrophages cells (BMMs). This is the first report of osteoclastogenesis inhibitory activity for the metabolites of these kinds. Besides, compounds 1, 2, 4, and 6–8 showed inhibitory activity against marine biofilm-forming bacteria, methicillin-resistant Staphylococcus aureus, Microbulbifer variabilis, Marinobacterium jannaschii, and Vibrio pelagius, with their MIC values ranging from 2 to 64 μg/mL. These findings provide a basis for further development of chlorinated polyketides as potential inhibitors of osteoclast differentiation and/or for use as anti-fouling agents.

A37 EFFICACY AND SAFETY OF RISANKIZUMAB AS MAINTENANCE THERAPY IN PATIENTS WITH CROHN’S DISEASE: 52 WEEK RESULTS FROM THE PHASE 3 FORTIFY STUDY

Background

Risankizumab (RZB), an anti-IL-23 p19 inhibitor, was well-tolerated and superior to placebo (PBO) in inducing clinical remission and endoscopic response in patients (pts) with moderate-to-severe Crohn’s disease (CD) in two phase 3 studies at 12 weeks.

Aims

FORTIFY (NCT03105102), was a 52-week (wk) phase 3 double-blind, re-randomized responder withdrawal study that evaluated the efficacy and safety of continuing RZB as subcutaneous (SC) maintenance therapy versus withdrawal to placebo in pts achieving induction response to RZB

Methods

Week 12 IV RZB responders were re-randomized 1:1:1 to: RZB SC 360mg (N=141), RZB 180mg (N=157), or PBO (withdrawal from IV RZB; N=164) every 8wks for 52wks. Co-primary endpoints were clinical remission (per CD Activity Index [CDAI] (US); or stool frequency/abdominal pain score [SF/APS] (OUS) and endoscopic response at wk52. Other clinical and endoscopic endpoints, inflammatory biomarkers, RZB serum levels, and safety were assessed over time.

Results

Rates of clinical remission (CDAI, SF/APS) and clinical response were similar for RZB and PBO groups through wk24, with rates lower for PBO thereafter. At wk52, clinical remission (CDAI, SF/APS) and endoscopic response rates were significantly higher with RZB 360mg than PBO ( P<0.01); RZB 180mg was superior to PBO for clinical remission per CDAI and endoscopic response ( P<0.01). Endoscopic remission and deep remission rates increased over time with 360mg, remained steady with 180mg, and decreased with PBO. Mean fecal calprotectin (FCP) and C-reactive protein (CRP) levels decreased with SC RZB, but increased with PBO, over 52wks. Exposure-adjusted event rates (per 100 pts-years) of serious adverse event (AE) were generally similar among groups (360mg, 21.0 E/100PY and 180mg, 19.5 E/100PY vs PBO, 19.3 E/100PY), as were AEs leading to drug discontinuation (4.8 E/100PY and 2.4 E/100PY vs 3.7 E/100PY), and serious infections (6.0 E/100PY and 3.0 E/100PY vs 5.0 E/100PY).

Conclusions

In pts with moderate-to-severe CD, a robust pharmacodynamic effect on the IL-23 pathway after 12wks RZB IV induction was maintained with RZB SC maintenance therapy. The durability of RZB was demonstrated with high rates of efficacy over the 52-wk study. RZB was superior to PBO for achieving clinical remission and endoscopic response at wk52. Results for the more stringent endpoints (endoscopic remission\deep remission) and persistent improvements in inflammatory biomarkers are consistent with a dose response relationship. Continued RZB SC maintenance treatment was generally safe and well-tolerated.

Funding Agencies

AbbVie

Efficacy and safety of iodine-125 particle implantation for treatment of bone metastatic tumor pain: a retrospective analysis

OBJECTIVE

Patients with advanced tumors often suffer from spinal metastatic tumor pain. The current drugs are less effective and have side effects. The objective was to explore the efficacy of iodine-125 particle implantation in the treatment of bone metastatic tumor pain.

PATIENTS AND METHODS

In a retrospective study, a total of 27 patients with bone metastatic tumors who could not receive surgery or radiotherapy and chemotherapy were analyzed. All patients received conventional treatment, with the visual analog scale (VAS) of >3 points, and the daily onset pain of >3 times. All patients received CT-guided iodine-125 particle implantation to treat local painful lesions. VAS scores were recorded before treatment (T0) and 1 day (T1), 7 days (T2), 30 days (T3), 90 days (T4), and 180 days (T5) after treatment. Kaplan-Meier analytical method was used to calculate the local control rate (LCR) and survival rate (SR).

RESULTS

All patients successfully completed the CT-guided iodine-125 particle implantation. There was no significant difference in VAS scores before and 1 day after surgery. However, compared with pre-operation, the VAS scores decreased at 7, 30, 90, and 180 days after surgery. The postoperative follow-up was 6-38 months, with a median of 16 months; the LCR at 1, 2, and 3 years after the follow-up were 87%, 51%, and 21%, respectively, and the SR was 84%, 43%, and 16%, respectively. Moreover, no serious adverse reactions were observed.

CONCLUSIONS

Iodine-125 particle implantation was effective in the treatment of bone metastatic tumor pain without serious complications, and hence, can be used clinically.

End-to-end orientation estimation from 2D cryo-EM images

Cryo-electron microscopy (cryo-EM) is a Nobel Prize-winning technique for determining high-resolution 3D structures of biological macromolecules. A 3D structure is reconstructed from hundreds of thousands of noisy 2D projection images. However, existing 3D reconstruction methods are still time-consuming, and one of the major computational bottlenecks is recovering the unknown orientation of the particle in each 2D image. The dominant methods typically exploit an expensive global search on each image to estimate the missing orientations. Here, a novel end-to-end supervised learning method is introduced to directly recover the missing orientations from 2D cryo-EM images. A neural network is used to approximate the mapping from images to orientations. A robust loss function is proposed for optimizing the parameters of the network, which can handle both asymmetric and symmetric 3D structures. Experiments on synthetic data sets with various symmetry types confirm that the neural network is capable of recovering orientations from 2D cryo-EM images, and the results on a real cryo-EM data set further demonstrate its potential under more challenging imaging conditions.

[A study on the identification of threshold for early warning on adverse weather events based on the association of apparent temperature and years of life lost]

Objective: To identify the threshold of a health warning system based on the association of apparent temperature and years of life lost (YLL). Methods: Daily mortality records and meteorological data were collected from 364 Chinese counties for 2006-2017. Distributed lag nonlinear model and multivariate Meta-analyses were applied to estimate the association between the apparent temperature and YLL rate. A regression tree model was employed to estimate the warning thresholds of the apparent temperature. Stratified analyses were further conducted by age and cause of death. Results: The daily YLL rate was 23.6/10⁵. The mean daily apparent temperature was 15.7 ℃. U-shaped nonlinear associations were observed between apparent temperature and YLL rate. The actual temperature-caused YLL rate for the elderly was higher than the young population. The daily excess deaths rate increased with the higher effect levels. Conclusions: Regression tree model was employed to define the warning threshold for meteorological health risk. The present study provides theoretical support for the weather-related health warning system.

Efficacy and correlative analyses of avelumab plus axitinib versus sunitinib in sarcomatoid renal cell carcinoma: post hoc analysis of a randomized clinical trial

BACKGROUND

Among patients with advanced renal cell carcinoma (RCC), those with sarcomatoid histology (sRCC) have the poorest prognosis. This analysis assessed the efficacy of avelumab plus axitinib versus sunitinib in patients with treatment-naive advanced sRCC.

METHODS

The randomized, open-label, multicenter, phase III JAVELIN Renal 101 trial (NCT02684006) enrolled patients with treatment-naive advanced RCC. Patients were randomized 1 : 1 to receive either avelumab plus axitinib or sunitinib following standard doses and schedules. Assessments in this post hoc analysis of patients with sRCC included efficacy (including progression-free survival) and biomarker analyses.

RESULTS

A total of 108 patients had sarcomatoid histology and were included in this post hoc analysis; 47 patients in the avelumab plus axitinib arm and 61 in the sunitinib arm. Patients in the avelumab plus axitinib arm had improved progression-free survival [stratified hazard ratio, 0.57 (95% confidence interval, 0.325-1.003)] and a higher objective response rate (46.8% versus 21.3%; complete response in 4.3% versus 0%) versus those in the sunitinib arm. Correlative gene expression analyses of patients with sRCC showed enrichment of gene pathway scores for cancer-associated fibroblasts and regulatory T cells, CD274 and CD8A expression, and tumors with The Cancer Genome Atlas m3 classification.

CONCLUSIONS

In this subgroup analysis of JAVELIN Renal 101, patients with sRCC in the avelumab plus axitinib arm had improved efficacy outcomes versus those in the sunitinib arm. Correlative analyses provide insight into this subtype of RCC and suggest that avelumab plus axitinib may increase the chance of overcoming the aggressive features of sRCC.

Unusually thick shear-softening surface of micrometer-size metallic glasses

The surface of glass is crucial for understanding many fundamental processes in glassy solids. A common notion is that a glass surface is a thin layer with liquid-like atomic dynamics and a thickness of a few tens of nanometers. Here, we measured the shear modulus at the surface of both millimeter-size and micrometer-size metallic glasses (MGs) through high-sensitivity torsion techniques. We found a pronounced shear-modulus softening at the surface of MGs. Compared with the bulk, the maximum decrease in the surface shear modulus (G) for the micro-scale MGs reaches ~27%, which is close to the decrease in the G upon glass transition, yet it still behaves solid-like. Strikingly, the surface thickness estimated from the shear-modulus softening is at least 400 nm, which is approximately one order of magnitude larger than that revealed from the glass dynamics. The unusually thick surface is also confirmed by measurements using X-ray nano-computed tomography, and this may account for the brittle-to-ductile transition of the MGs with size reductions. The unique and unusual properties at the surface of the micrometer-size MGs are physically related to the negative pressure effect during the thermoplastic formation process, which can dramatically reduce the density of the proximate surface region in the supercooled liquid state.

•

The shear modulus and thickness of metallic glass (MG) surface is determined through torsion testing on micrometer-size wires

•

The surface region of MG wires has a significant shear-modulus softening close to the supercooled liquid, yet still behaves solid-like

•

The thickness of the soft surface of MG wires is at least 400 nm, which is about one order of magnitude larger than those revealed from surface dynamics

•

The unusually thick surface accounts for the brittle-to-ductile transition of the MGs with size reduction

The true incidence of chromosomal mosaicism after preimplantation genetic testing is much lower than that indicated by trophectoderm biopsy

STUDY QUESTION

What is the true incidence of chromosomal mosaicism in embryos analyzed by preimplantation genetic testing (PGT).

SUMMARY ANSWER

The true incidence of chromosomal mosaicism is much lower than we usually surmise.

WHAT IS KNOWN ALREADY

In recent years, contemporary methods for chromosome analysis, along with the biopsy of more than one cell, have given rise to an increased rate of chromosomal mosaicism detection after preimplantation genetic testing for aneuploidy. However, the exorbitant incidence of mosaicism represents a dilemma and imposes restrictions on the application of PGT treatment. Concern has been raised about the possibility that the incidence of chromosomal mosaicism is overestimated and quite a few of the results are false-positive errors. However, studies verifying the diagnosis of chromosomal mosaicism and assessing the true incidence of chromosomal mosaicism are limited.

STUDY DESIGN, SIZE, DURATION

A total of 1719 blastocysts from 380 patients who underwent PGT treatment were retrospectively analyzed to evaluate the typical incidence of mosaicism. Then 101 embryos donated by 70 couples were re-biopsied and dissected into three portions if available: trophectoderm (TE), inner cell mass (ICM), and the remaining portions. All the portions were tested using next-generation sequencing (NGS), and the results were compared to the original diagnosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The setting for this study was a university-affiliated center with an in-house PGT laboratory. All samples were amplified with multiple annealing and looping-based amplification cycles (MALBACs) and the NGS was carried out on a Life Technologies Ion Proton platform.

MAIN RESULTS AND THE ROLE OF CHANCE

A clinical TE biopsy revealed an incidence of 11.9% for diploid-aneuploid mosaicism (DAM), 17.3% for aneuploid mosaicism (AM) and 29.1% in total. After rebiopsy, 94.1% whole-chromosome aneuploidies and 82.8% segmental-chromosome aneuploidies were confirmed in the embryos. As for the mosaic errors, only 32 (31.7%) out of 101 embryos presented with uniform chromosomal aberrations in agreement with the original biopsy results, 15 (14.8%) embryos presented with de novo chromosomal aberrations, and 54 (53.5%) embryos showed a euploid profile in all portions. Among the 32 uniform embryos, the true mosaicism was confirmed in only 4 cases, where a reciprocal chromosomal aberration was identified; 14 embryos presented with identical mosaicism, providing the moderate evidence for true mosaicism; and 14 embryos displayed uniform full aneuploidies in all portions of embryo, revealing a high-grade mosaicism or a false-negative diagnosis. Logistical regression analysis revealed that the concordance rate with ICM was associated with the type and level of mosaicism. The concordance rate of segmental-chromosome mosaicism was significantly lower than whole-chromosome mosaicism (adjusted Odds Ratio (aOR): 5.137 (1.061, 24.876), P = 0.042) and compared to DAM, the concordance rate of AM was significantly higher (aOR: 6.546 (1.354, 31.655), P = 0.019). The concordance rate also increased with increasing levels of mosaicism (P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

This study was limited by a small sample size and the use of a single whole-genome amplification (WGA) method and NGS platform. These findings are only applicable to samples subjected to MALBAC amplification and Ion Proton platform, and studies involving larger sample sizes and multiple WGA methods and NGS platforms are required to prove our findings.

WIDER IMPLICATIONS OF THE FINDINGS

TE biopsy is reliable to detect whole-chromosome aneuploidies, but the ability to diagnose mosaicism is doubtful. More attention should be paid to false-positive and false-negative errors in NGS-based PGT, especially for laboratories using less stringent criteria for mosaicism classification (i.e. 20-80%), which might be subject to a much higher false-positive mosaicism rate in the practice.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the National Key R&D Program of China (No. 2016YFC1000206-5) and the National Natural Science Foundation of China (No. 81701509).

TRIAL REGISTRATION NUMBER

N/A.

Phosphatidic acid and hydrogen peroxide coordinately enhance heat tolerance in tall fescue

Phosphatidic acid (PA) and hydrogen peroxide (H₂ O₂ ) play roles in regulating plant responses to abiotic stress. The objective of this study was to determine effects of H₂ O₂ or PA, individually and interactively, with a H₂ O₂ scavenging molecule, N,N'-dimethylthoiurea (DMTU), on plant tolerance to heat stress in tall fescue (Festuca arundinacea). Plants were treated with PA (25 µm), H₂ O₂ (5 mm) and PA (25 µm) + DMTU (5 mm) by foliar application and then exposed to heat stress (38/33 °C) or optimal temperature (23/18 °C, day/night) for 28 days. Foliar application of PA and H₂ O₂ alone resulted in increases in leaf fresh weight, chlorophyll content, photochemical efficiency and cellular membrane stability in plants exposed to heat stress, whereas addition of DMTU suppressed the positive effects of PA. Expression levels of genes encoding the PA synthesizing enzyme, FaPLDδ, were significantly up-regulated by H₂ O₂ . Phosphatidic acid- or H₂ O₂ -enhanced heat tolerance was associated with the activation of stress signalling components (FaCDPK3, FaMPK6, FaMPK3), transcription factors (FaMBF1 and FaHsfA2c) and heat shock proteins (FaHSP18, FaHSP70 and FaHSP90). Phosphatidic acid and H₂ O₂ may work in coordination to further improve heat tolerance, involving up-regulation of transcription factors in stress signalling cascades and heat protection systems.

DeProCams: Simultaneous Relighting, Compensation and Shape Reconstruction for Projector-Camera Systems

Image-based relighting, projector compensation and depth/normal reconstruction are three important tasks of projector-camera systems (ProCams) and spatial augmented reality (SAR). Although they share a similar pipeline of finding projector-camera image mappings, in tradition, they are addressed independently, sometimes with different prerequisites, devices and sampling images. In practice, this may be cumbersome for SAR applications to address them one-by-one. In this paper, we propose a novel end-to-end trainable model named DeProCams to explicitly learn the photometric and geometric mappings of ProCams, and once trained, DeProCams can be applied simultaneously to the three tasks. DeProCams explicitly decomposes the projector-camera image mappings into three subprocesses: shading attributes estimation, rough direct light estimation and photorealistic neural rendering. A particular challenge addressed by DeProCams is occlusion, for which we exploit epipolar constraint and propose a novel differentiable projector direct light mask. Thus, it can be learned end-to-end along with the other modules. Afterwards, to improve convergence, we apply photometric and geometric constraints such that the intermediate results are plausible. In our experiments, DeProCams shows clear advantages over previous arts with promising quality and meanwhile being fully differentiable. Moreover, by solving the three tasks in a unified model, DeProCams waives the need for additional optical devices, radiometric calibrations and structured light.