Identification of RNA silencing suppressor encoded by wheat blue dwarf (WBD) phytoplasma

Plants possess an innate immune system for defence against pathogens. In turn, pathogens have various strategies to overcome complex plant defences. Among diverse pathogens, phytoplasmas are associated with serious diseases in a range of species. RNA silencing serves as an efficient defence system against pathogens in eukaryotes but can be interrupted by RNA silencing suppressors (RSSs) encoded by pathogens. Currently, many RSSs have been identified in viruses, bacteria, oomycetes and fungi. Phytoplasmas are pathogens in several hundred plant species. In this research, 37 candidate effectors of wheat blue dwarf (WBD) phytoplasma were screened for presence of RSS. Agro-infiltration assay, yeast expression system, floral-dip method for constructing transgenic A. thaliana, Western blotting and RT-qPCR were used for identification of RNA silencing suppressors. SWP16 encoded by WBD phytoplasma was found to be a secretory protein that inhibited accumulation of GFP siRNA and led to the accumulation of GPF mRNA in systemic N. benthamiana 16c. Furthermore, in A. thaliana SWP16 inhibited production of miRNAs, which are components of RNA silencing. SWP16 also promoted infection of potato virus X. We conclude that SWP16 encoded by WBD phytoplasma was an RSS, suppressing systemic RNA silencing. This is the first evidence that a phytoplasma encodes an RSS and provides a theoretical basis for research on the interaction mechanisms between pathogens and plants.

Retrospective analysis of molecular biology mechanism of ABO blood group typing discrepancy among blood donors in Jinan blood station

BACKGROUND

To accurately identify ABO blood typing in pre-transfusion testing is very important to ensure blood transfusion safely, which is a major responsibility of blood station.

METHODS

Eighty-one blood donors samples with ABO blood group typing discrepancy was collected among 61952 donor samples in our blood station from January 2019 to July 2020. Blood group serological method was used to detect ABO blood group. DNA Sequencing was used to determine the genotype. The antibody screening test detects antibodies other than ABO.

RESULTS

In total, 61,952 donor samples were analysed for ABO typing discrepancies. The incidence among blood donors was 0.13% (81/61952). The most common reason of ABO typing discrepancies was due to specific antibody or non-specific agglutination (54.32%, 44/81), mainly anti-M antibody, cold autoantibody, anti-D antibody, anti-N antibody and anti-Lea antibody. The major cause of forward typing discrepancies among blood donors was ABO subgroups (25.93%, 21/81), including 10 cases of A subtype (1 case of A2, 2 cases of A3, 2 cases of Ax, 3 cases of AxB, 1 case of Ael, 1 case of Ahm), 6 cases of B subtype (2 cases of B3, 1 case of Bel, 3 cases of AB3), 2 cases of B subtype (A), 1 case of cisAB, and 2 cases of acquired B. The serum antibody was weakened in 16 cases (19.75%).

CONCLUSIONS

The blood types should be correctly identified by combining serology with gene sequencing to ensure the safety of clinical blood transfusion, when the forward and reverse typing discrepancies among the blood donors.

[Application of aMAP score to assess the risk of hepatocarciongenesis in population of chronic liver disease in primary hospitals]

Objective: The aMAP score is a hepatocellular carcinoma (HCC) risk prediction model based on an international cooperative cohort, which can be applied to various liver diseases. The aim of this study is to use the aMAP score to stratify the risk of HCC in patients with chronic liver disease (combined or non-combined metabolic diseases) admitted to People's Hospital of Yudu County, Ganzhou City, Jiangxi Province, in order to guide personalized HCC screening. Methods: The demographic information, laboratory test results (platelets, albumin, and total bilirubin) and combined disease information of patients with chronic liver disease who were admitted to People's Hospital of Yudu from January 2016 to December 2020 were collected, and the aMAP score was calculated to stratify HCC risk in this population. Results: A total of 3629 cases with chronic liver disease were included in the analysis, including 3 452 (95.1%) cases with hepatitis B virus (HBV) infection, 177 (4.9%) cases with fatty liver, and 22 (0.6%) cases with HBV infection and fatty liver. There were 2 679 (73.8%) male and the median age was 44 (35, 54). In the overall population, low, medium and high risk of HCC accounted for 52.6%, 29.0%, and 18.4% respectively. In the HBV-infected population, the proportion of high risk of HCC was significantly higher than that of fatty liver (18.9% vs. 9.6%, P = 0.001). The proportion of chronic liver disease patients with combined hypertension or diabetes was significantly higher than that of those with non-combined metabolic diseases (combined hypertension: 32.3% vs. 17.9%, P < 0.001; combined diabetes: 36.5% vs. 18.1%, P < 0.001). Moreover, the proportion of high-risk population with two metabolic diseases was significantly higher than that with one and no metabolic diseases (40.9% vs. 31.8% vs. 17.7%, P < 0.001). Conclusion: The aMAP score can be used as a simple tool for HCC screening and management of chronic liver disease in primary hospitals, and it is helpful to improve the personalized follow-up management system of chronic liver disease population. Chronic liver disease patients with metabolic diseases have a higher risk of HCC, and people with high risk of HCC should be given special priority in follow-up visits, so as to improve the rate of HCC early diagnosis and reduce the mortality rate.

[Establishing an integrated hospital-community pyramid for screening and achieving hepatocellular carcinoma early diagnosis and treatment]

The comprehensive management of hepatocellular carcinoma (HCC) is a complete, dynamic and personalized process. Therefore, how to scientifically determine the HCC high-risk/extremely high-risk populations and develop a stratified monitoring plan is the key link to early detection, diagnosis and improvement of overall survival. In addition, accurately identifying high-risk/extremely high-risk groups based on the HCC risk prediction model, and applying it to establish an integrated hospital-community pyramid for HCC screening through the implementation of interdisciplinary scientific management and treatment may ultimately reduce HCC-related mortality rate.

[Role and related mechanism of Mst-1 on regulating hypoxic reoxygenation induced autophagy and apoptosis in cardiomyocytes of mouse]

Objective: To explore the role and related mechanism of mammalian sterile 20-like kinase 1(Mst-1)in regulating hypoxia reoxygenation (HR) induced myocardial cell autophagy and apoptosis. Methods: Enzyme digestion method combined with differential adherent method was used to culture neonatal mouse myocardial cells. HR model was established by hypoxia for 24 hours and reoxygenation for 6 hours. The experimental groups including control group (normal cultured cardiomyocytes), Mst-1 empty virus group (cardiomyocytes transfected with recombinant lentiviral empty vector for 48 hours), Mst-1 knockdown group (recombinant lentivirus carrying Mst-1small interfering RNA (siRNA) was transfected into cardiomyocytes for 48 hours), Mst-1 overexpression group (cardiomyocytes were transfected with recombinant lentivirus carrying Mst-1 gene for 48 hours), HR group (cardiomyocytes exposed to HR), Mst-1 knockdown+HR group (HR model of cardiomyocyte was established 48 hours after transfection with recombinant lentivirus carrying Mst-1siRNA) and Mst-1 overexpression+HR group (HR model of cardiomyocyte was established 48 hours after transfection with recombinant lentivirus carrying Mst-1 gene). Real-time fluorescence quantitative RCR (qPCR) and Western blot were used to detect the relative expression of Mst-1 mRNA and protein in the cells, immunofluorescence staining was used to detect cardiomyocyte troponin T (cTnT), and autophagosomes and autophagy enzyme changes. TUNEL method was used to detect myocardial cell apoptosis, Western blot was adopted to detect autophagy-related protein microtubule-related protein 1 light chain 3 (LC3) Ⅱ/LC3 Ⅰ, P62 and apoptosis-related protein cleaved-caspase 9, pro-caspase 9, cleaved-caspase-3, pro-caspase-3, and myeloid leukemia 1 (MCL-1) expression. MCL-1 inhibitor A1210477 was used to validate the signaling pathway of Mst-1 on regulating cardiomyocyte apoptosis and autophagy. Results: Immunofluorescence detection revealed that the cultured cells expressed cardiomyocyte-specific marker cTnT. The expression of Mst-1 in cardiomyocytes increased in HR model. Lentiviral transfection could effectively inhibit or overexpress Mst-1 in treated cells. The levels of autophagosomes and autophagolysosomes in cardiomyocytes undergoing HR and in Mst-1 overexpression+HR group were lower than those of control group, while autophagosomes and autophagolysosomes in cardiomyocytes of Mst-1 knockdown+HR group was significantly higher than in the HR group (all P<0.05). The TUNEL results showed that the proportion of TUNEL positive cells was significantly increased in the HR group and Mst-1 overexpression+HR group than in the control group, while the proportion of TUNEL positive cells was significantly decreased in the Mst-1 knockdown group+HR group as compared to the HR group (all P<0.05). Western blot results showed that the LC3 Ⅱ/LC3 Ⅰ levels were significantly lower, while the expression levels of P62, cleaved-caspase-9 and cleaved-caspase-3 were significantly higher in the HR group and Mst-1 overexpression+HR group than in control group (all P<0.05). The LC3 Ⅱ/LC3 Ⅰ value was significantly higher, and the expression levels of P62, cleaved-caspase-9 and cleaved-caspase-3 were significantly lower in the Mst-1 knockdown+HR group than in the HR group (P both<0.05). The expression level of P-MCL-1 protein was significantly lower in cardiomyocytes of HR and Mst-1 overexpression+HR group than in control group, and the expression level of P-MCL-1 protein was higher in Mst-1 knockdown+HR group than in HR group (P both<0.05). The recovery experiment showed that inhibiting MCL-1 in cells can block the regulatory effect of Mst-1 siRNA on cell autophagy and apoptosis. Conclusion: Inhibiting Mst-1 expression in cardiomyocytes can promote the autophagy of cardiomyocytes induced by hypoxic reoxygenation and reduce the apoptosis of cardiomyocytes via activating McL-1.

Contribution of single-gene defects to congenital cardiac left-sided lesions in the prenatal setting

OBJECTIVES

To explore the contribution of single-gene defects to the genetic cause of cardiac left-sided lesions (LSLs), and to evaluate the incremental diagnostic yield of whole-exome sequencing (WES) for single-gene defects in fetuses with LSLs without aneuploidy or a pathogenic copy-number variant (pCNV).

METHODS

Between 10 April 2015 and 30 October 2018, we recruited 80 pregnant women diagnosed with a LSL who had termination of pregnancy and genetic testing. Eligible LSLs were aortic valve atresia or stenosis, coarctation of the aorta, mitral atresia or stenosis and hypoplastic left heart syndrome (HLHS). CNV sequencing (CNV-seq) and WES were performed sequentially on specimens from these fetuses and their parents. CNV-seq was used to identify aneuploidies and pCNVs, while WES was used to identify diagnostic genetic variants in cases without aneuploidy or pCNV.

RESULTS

Of 80 pregnancies included in the study, 27 (33.8%) had a genetic diagnosis. CNV-seq analysis identified six (7.5%) fetuses with aneuploidy and eight (10.0%) with pCNVs. WES analysis of the remaining 66 cases revealed diagnostic genetic variants in 13 (19.7%) cases, indicating that the diagnostic yield of WES for the entire cohort was 16.3% (13/80). KMT2D was the most frequently mutated gene (7/66 (10.6%)) in fetuses with LSL without aneuploidy or pCNVs, followed by NOTCH1 (4/66 (6.1%)). HLHS was the most prevalent cardiac phenotype (4/7) in cases with a KMT2D mutation in this cohort. An additional six (9.1%) cases were found to have potentially deleterious variants in candidate genes.

CONCLUSIONS

Single-gene defects contribute substantially to the genetic etiology of fetal LSLs. KMT2D mutations accounted for approximately 10% of LSLs in our fetal cohort. WES has the potential to provide genetic diagnoses in fetuses with LSLs without aneuploidy or pCNVs. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Hepatitis E virus infection in buffaloes in South China

ABSTRACT Hepatitis E virus (HEV) infection is an important global public health issue. HEV infections are recognized as a zoonotic disease. Swine are believed to be the main reservoir of HEV. Recently, yaks, cows, and yellow cattle have been reported as new reservoirs of HEV. However, whether other species of cattle and buffaloes are sensitive to HEV infection is unknown. To investigate the prevalence of HEV infection in buffaloes, enzyme-linked immunosorbent assay (ELISA) and reverse transcription-nested polymerase chain reaction (RT-nPCR) were performed. Only one buffalo was positive to anti-HEV IgM antibody (1/106, 0.94%), and none were positive for anti-HEV IgG antibody. To our surprise, five serum (5/106, 4.72%) and three milk samples (3/40, 7.50%) from buffaloes were positive to HEV RNA. All strains of HEV isolated from buffaloes belong to genotype 4. Results indicate that buffaloes may be a new reservoir of HEV.

Mitochondrial ribosomal protein S9M is involved in male gametogenesis and seed development in Arabidopsis

Mitochondrial function is critical for cell vitality in all eukaryotes including plants. Although plant mitochondria contain many proteins, few have been studied in the context of plant development and physiology. We used knock-down mutant RPS9M to study its important role in male gametogenesis and seed development in Arabidopsis thaliana. Knock-down of RPS9M in the rps9m-3 mutant led to abnormal pollen development and impaired pollen tube growth. In addition, both embryo and endosperm development were affected. Phenotype analysis revealed that the rps9m-3 mutant contained a lower amount of endosperm and nuclear proteins, and both embryo cell division and embryo pattern were affected, resulting in an abnormal and defective embryo. Lowering the level of RPS9M in rps9m-3 affects mitochondrial ribosome biogenesis, energy metabolism and production of ROS. Our data revealed that RPS9M plays important roles in normal gametophyte development and seed formation, possibly by sustaining mitochondrial function.

Identification of antimicrobial metabolites produced by a potential biocontrol Actinomycete strain A217

AIMS

To extract and identify the metabolites of strain A217 as well as its antifungal spectrum and control effect on various plant pathogens.

METHODS AND RESULTS

Strain A217 was identified as a Streptomyces sp. which was most similar to Streptomyces lienomycini. An antimicrobial spectrum test indicated that strain A217 inhibited several plant pathogenic fungi and strong antibacterial effect such as Phytophthora capsici, Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium oxysporum, Pseudomonas syringae and Xanthomonas campestris. An in vivo tissue test demonstrated that the fermentation broth of strain A217 exerted therapeutic and protective effects of 49·47 and 61·60% respectively, on S. sclerotiorum. Additionally, the fermentation broth of A217 exerted control effects on walnut black spot disease in walnut leaves and branches amounting to 79·33 and 81·52% respectively. In a pot experiment, the fermentation broth exhibited a stronger protective and control effect (68·29%), as well as better bacteriostatic and disease control effects on Phytophthora blight of pepper, compared with Metalaxyl. Compounds possessing antifungal and antibacterial activities were obtained from the fermentation broth of strain A217, using column chromatography and HPLC. Chemical and structural analyses conducted using MS and nuclear magnetic resonance confirmed that these compounds were 1H-pyrrole-2-carboxylic acid and 1H-pyrrole-2-carboxamide. The EC₅₀ values of compound 1H-pyrrole-2-carboxylic acid1 for S. sclerotiorum and P. capsici were 20·13 and 50·36 μg ml^-1 respectively. Compound 1H-pyrrole-2-carboxamide2 showed significant antibacterial activity against different plant pathogenic bacteria. The MIC values of P. syringae, X. campestris and X. campestris pv. jugiandis were 7·5, 30 and 15·0 μg ml^-1 respectively.

CONCLUSIONS

Actinomyces A217 fermentation products have a broad spectrum of bacteriostasis, and have good bacteriostasis activity to many plant pathogenic fungi and bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study revealed a new antimicrobial producing strain of Streptomyces and its potential application as a biological control agent for plant diseases.

[Effect of resection of adenoids and/or tonsil on the immune indexes in children with obstructive sleep apnea hypopnea syndrome]

Objective: To study the effect on immune indexes in children with obstructive sleep apnea hypopnea syndrome (OSAHS) before and after resection of adenoid and/or tonsil. Methods: A total of 100 children with OSAHS due to adenoid hypertrophy were enrolled in Department of Otorhinolaryngology Head and Neck Surgery, the Second Hospital of Dalian Medical University from December 2016 to December 2018. Some cases were complicated with tonsil hypertrophy or chronic tonsillitis. 6 ml of fasting peripheral venous blood were collected from all subjects at the 1st day before surgery, 4th day, 1 month, 3 months and 6 months after surgery to detect lymphoid subsets percentage (CD3(+), CD4(+),CD8(+), CD4/CD8, CD19, NK) and level of immunoglobulin (IgG, IgA, IgM). Grouping: group A was a total of 51 cases with adenoid hypertrophy after Adenoid plasma ablation; group B was a total of 27 cases with adenoid hypertrophy and chronic tonsillitis after plasma ablation of adenoid and tonsil; and group C was a total of 22 cases hypertrophy of adenoid and tonsil after plasma ablation of adenoid and tonsil.In the baseline data, age, gender and other variables were analyzed by anova and chi-square test, repeated measurement anova was used for intra-group and inter-group comparison of observation indicators at different time points after operation, and independent sample t-test was used for comparison between the two groups at observation points 3 months after operation. Results: (1) In group A, the percentage of CD19 lymphocytes before surgery was higher than that at 4th day after surgery, and the difference was statistically significant (21.85±6.20 vs.19.18±5.91, P<0.05). The other immune indexes were not statistically different before and after surgery (P>0.05). (2) In group B, the percentage of CD19 lymphocytes, CD3(+)T lymphocytes, CD8(+)T lymphocytes and the level of IgG at 4th day after surgery were significantly different between those before surgery (all P<0.05). At the 1st month after surgery, the percentage of CD3(+)T lymphocytes, CD8(+)T lymphocytes, CD19 lymphocytes and the level of IgG were significantly different between those before surgery (all P<0.05). The other immune indexes were not statistically different before and after operation (P>0.05). (3) In group C, the percentage of CD19 lymphocytes and the CD3(+)T lymphocytes at 4th day after surgery were significantly different between those before surgery (all P<0.05).In the 1st month after surgery, the percentage of CD8(+)T lymphocytes and CD19 lymphocytes were significantly different between those before surgery (all P<0.05). The other immune indexes were not statistically different before and after operation (P>0.05). (4) Among three groups, the percentage of CD4(+)T lymphocytes, the levels of IgG and IgA before surgery between group A and Group B were statistically significant (all P<0.05). At 4th day after surgery, the percentage of CD4(+)T lymphocytes in group B and C were lower than those in group A, and the differences were statistically significant (32.22±6.14, 32.36±6.87 vs. 36.36±5.19, all P<0.05); the other immune indexes were not statistically different among each group before and after surgery (P>0.05). Conclusions: Resection of adenoid has no significant effect on the immune indexes in children with OSAHS. The children with OSAHS complicated with tonsil problems have immune index disorder before surgery. Surgery has a certain effect on the immune indexes of children with OSAHS in a short period of time, and tends to normal level after one month.

Fetal cardiac tumor: echocardiography, clinical outcome and genetic analysis in 53 cases

OBJECTIVE

To analyze the imaging and clinical features of fetal cardiac tumors, and to explore the relationship between tuberous sclerosis complex (TSC) and cardiac rhabdomyoma in the fetus.

METHODS

Fifty-three women pregnant with a fetus affected by cardiac tumor(s) were examined by standardized fetal echocardiography (FE), and fetuses, mothers and fathers, including other relevant family members if necessary, underwent familial TSC genetic testing. Relevant pathological features, including pathological findings at clinical examination of liveborn infants and autopsy findings in terminated cases, were noted.

RESULTS

Of the 53 fetuses, 37 had multiple cardiac tumors and 16 had a single cardiac tumor detected by FE. In all 53 fetuses and their families, TSC genetic testing was successful, showing that 37 of the fetuses had a TSC1 (n = 6) or TSC2 (n = 31) pathogenic or suspected pathogenic mutation, of which 25 were spontaneous and 12 were familial mutations. The proportion of single and multiple cardiac tumors at FE was significantly different between the group of fetuses with positive genetic test results and that with negative results for TSC (31% and 86%, respectively), although the presence of multiple or single tumors was not associated with the type of TSC mutation. The decision to terminate the pregnancy was made by 45 women and their families, and eight fetuses were liveborn. Autopsy was performed in 38 fetuses, which revealed 36 cases with pathologically confirmed cardiac rhabdomyoma, one case of hemangioma and one case of fibroma. 93% of fetuses with multiple rhabdomyomas at autopsy and 71% of those with a single cardiac rhabdomyoma harbored a TSC1 or TSC2 mutation.

CONCLUSION

Cardiac rhabdomyoma is the most common cardiac tumor in the fetus. The correlation between cardiac rhabdomyoma and TSC is strong regardless of the presence of single or multiple tumors. For fetuses with suspected cardiac rhabdomyoma identified by FE, prenatal genetic testing for TSC of both fetus and family members is recommended. A positive genetic diagnosis can help in counseling and planning for neonatal treatment. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Experimental Observation of Single Skyrmion Signatures in a Magnetic Tunnel Junction

We have deterministically created a stable topological spin texture in magnetic tunnel junctions (MTJ) by using pulsed or microwave currents. The spin texture is characterized by a field-dependent intermediate resistance state and a new magnetic resonance. Micromagnetic simulations show that the observations are consistent with the nucleation of a single skyrmion, facilitated by a spatially nonuniform stray field. The unique resonance spectrum is identified as the skyrmion breathing mode and a skyrmion diameter of 75 nm is estimated. This work shows the possibility to create skyrmions in MTJs without the Dzyaloshinskii-Moriya interaction and could lead to noninvasive, on-chip skyrmion measurement.