A novel pine wood nematode effector, BxSCD1, suppresses plant immunity and interacts with an ethylene-forming enzyme in pine.

The plant-parasitic nematode Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), causes enormous economic loss every year. Currently, little is known about the pathogenic mechanisms of PWD. Several effectors have been identified in B. xylophilus, but their functions and host targets have yet to be elucidated. Here, we demonstrated that BxSCD1 suppresses cell death and inhibits B. xylophilus PAMP BxCDP1-triggered immunity in Nicotiana benthamiana and Pinus thunbergii. BxSCD1 was transcriptionally upregulated in the early stage of B. xylophilus infection. In situ hybridization experiments showed that BxSCD1 was specifically expressed in the dorsal glands and intestine. Cysteine residues are essential for the function of BxSCD1. Transient expression of BxSCD1 in N. benthamiana revealed that it was primarily targeted to the cytoplasm and nucleus. The morbidity was significantly reduced in P. thunbergii infected with B. xylophilus when BxSCD1 was silenced. We identified 1-aminocyclopropane-1-carboxylate oxidase 1, the actual ethylene-forming enzyme, as a host target of BxSCD1 by yeast two-hybrid and coimmunoprecipitation. Overall, this study illustrated that BxSCD1 played a critical role in the B. xylophilus-plant interaction.

Comparative transcriptomic analysis of candidate effectors to explore the infection and survival strategy of Bursaphelenchus xylophilus during different interaction stages with pine trees.

BACKGROUND: The pine wood nematode (PWN), Bursaphelenchus xylophilus, is a devastating pathogen of many Pinus species in China. The aim of this study was to understand the interactive molecular mechanism of PWN and its host by comparing differentially expressed genes and candidate effectors from three transcriptomes of B. xylophilus at different infection stages. RESULTS: In total, 62, 69 and 46 candidate effectors were identified in three transcriptomes (2.5 h postinfection, 6, 12 and 24 h postinoculation and 6 and 15 d postinfection, respectively). In addition to uncharacterized pioneers, other candidate effectors were involved in the degradation of host tissues, suppression of host defenses, targeting plant signaling pathways, feeding and detoxification, which helped B. xylophilus survive successfully in the host. Seven candidate effectors were identified in both our study and the B. xylophilus transcriptome at 2.5 h postinfection, and one candidate effector was identified in all three transcriptomes. These common candidate effectors were upregulated at infection stages, and one of them suppressed pathogen-associated molecular pattern (PAMP) PsXEG1-triggered cell death in Nicotiana benthamiana. CONCLUSIONS: The results indicated that B. xylophilus secreted various candidate effectors, and some of them continued to function throughout all infection stages. These various candidate effectors were important to B. xylophilus infection and survival, and they functioned in different ways (such as breaking down host cell walls, suppressing host defenses, promoting feeding efficiency, promoting detoxification and playing virulence functions). The present results provide valuable resources for in-depth research on the pathogenesis of B. xylophilus from the perspective of effectors.

Prospective and prognostic factors for hepatic metastasis of gastric carcinoma: A retrospective analysis.

AIMS: The aim of the study was to prospectively explore the prognostic factor for gastric cancer with liver metastasis (GCLM), since no prognostic factor was reported to be consistently significant across studies. PATIENTS AND METHODS: One hundred and five patients with GCLM treated at our center between January 1, 2010, and March 31, 2016, were included and their clinical data were retrospectively analyzed. The univariate analyses were first applied for identify the potential independent prognostic and predictive factors for liver metastasis. These factors were further evaluated with Cox proportional-hazard regression model testing. Finally, survival curves were estimated. RESULTS: The Eastern Cooperative Oncology Group (ECOG) score, number of other distant metastases, levels of cancer antigen (CA), and carcinoembryonic antigen (CEA) were independent prognostic factors (adjusted relative risk [RR]: 1.362-2.887; P = 0.000-0.027). The survival of patients who received radical gastrectomy would be associated with the ECOG score, staging (T stage and N stage), CA 19-9, and CEA levels (RR: 2.169-3.787; P = 0.000-0.027). Patients with following indicators 1 month postoperatively were prone to liver metastasis after radical gastrectomy (median, 6.9-12.03 months; P = 0.007-0.042): Venous/lymphatic invasion, pathological Stage IV (especially combined with T4 stage), intestinal Lauren type, and combined elevation of CEA and CA 19-9 levels. CONCLUSIONS: The therapy design for patients with GCLM should consider the general conditions and personal clinicopathological characters of patients. After balancing the benefit and risk factors, multidisciplinary treatment and individual treatment should be developed based on evidence-based medicine model for each patient.

[Analysis of Absorption Characteristics of Urban Black-odor Water].

The urban black-odor water body has become a serious problem of urban water environment and identifying their optical characteristics in urban areas is the prerequisite and basis for their detection by remote sensing. A total of 85 samples of urban black-odor water, from Changsha, Nanjing, and Wuxi, were collected from 2016 to 2017, and a total of 80 samples were collected from non-black-odor (smelly) water samples. The water quality parameters such as suspended matter and the absorption coefficient were measured. The results showed that:①The total black-odor water body particulate matter absorption coefficients and non-pigmented particulate matter absorption coefficients were generally higher than those for non-black-odor water bodies and they had a certain degree of discrimination at 440 nm, but their effect was not significant. The absorption of relatively high levels of particulate matter in black-odor water was mainly due to high absorption of non-pigmented particles. In the data collected, non-pigmented particles in black-odor water accounted for more than 50% of the total particles. ② The Colored Dissolved Organic Matter (CDOM) absorption coefficients for black-odor water bodies and non-black-odor water bodies differed. The average absorption coefficient of CDOM at 440 nm for black-odor water bodies was 1.7 times higher than that for non-black-odor water bodies. Thus, the black-odor water body can be distinguished by using the slope of the absorption coefficient curve fitted in the characteristic wavelength band of 440 nm, as well as in different wavelength bands; the overall effect is good. However, as the wavelength increases, the discrimination effect decreases. Analysis of the absorption characteristics of urban black-odor water bodies will provide effective technical support for their detection by remote sensing and supervision, and the density of CDOM in black-odor water was generally high, which could be used as an important reference for identification.

[Remote Sensing Identification of Urban Black-Odor Water Bodies Based on High-Resolution Images:A Case Study in Nanjing].

The identification of urban black-odor water bodies plays an important role in monitoring and controlling black-odor water bodies. In 2016, a ground survey was conducted on the urban reach of Nanjing, and 55 samples from the West Shazhou River, Tuwei River, Xuanwu Lake, and Jinchuan River were obtained. The spectral characteristics of urban black-odor water bodies and other water bodies were analyzed. Recognition algorithms for GF-2 data were proposed in order to analyze the spatial distribution and environmental factors of urban black-odor water bodies. These algorithms were single-band thresholds based on reflectance of the green band, the difference between the blue band and green band, the ratio of the green band and red band, and the chromaticity value. The results indicate that:① compared with other types of water, the urban black-odor water has the smallest spectral slope in the range of 400-500 nm and lowest reflectivity, and the peaks and valleys are not prominent in the whole visible range; ② based on the verification, the accuracy of the ratio algorithm is the highest; and ③ using the ratio algorithm to calculate the GF-2 data of November 3, 2016, a total of 11 black river sections are identified. The entire length is 40.7 km, and the area is 0.749 km2.The black-odor water sections are distributed over a wide range but are not continuous, and they are concentrated in the densely populated areas. Domestic sewage, industrial waste water, and broken river channel are the main reasons.

[Remote Sensing of Chlorophyll-a Concentrations in Lake Hongze Using Long Time Series MERIS Observations].

Chlorophyll-a (Chl-a) concentrations are usually measured as the proxy of phytoplankton biomass and used to evaluate the trophic status of inland waters. Based on 49 in situ samples taken from two measurement campaigns in Lake Hongze in 2016, we evaluate the performance of five Chl-a estimation algorithms (including the band ratio, three-band, FLH algorithm, MCI, and UMOC algorithms). The results showed that the UMOC model was the most suitable model for the estimation of Chl-a in Lake Hongze. The mean relative error (MRE) of UMOC was 32.30%, much lower than the band ratio algorithm (75.17%), three-band algorithm (62.44%), FLH algorithm (45.87%), and MCI algorithm (56.95%). The best-performing UMOC model was applied to the atmospherically corrected 689 MERIS images between 2002-2012 and long time series MERIS Chl-a concentration estimation products were acquired. Between 2002 and 2012, the mean Chl-a concentration in Lake Hongze was 19.560 mg·m-3 with substantial spatial and temporal variability. Based on the variability of monthly mean Chl-a concentrations in each pixel, the Lake Hongze waterbody was divided into three water types, Region A, Region B, and Region C. The annual mean Chl-a concentrations of Region B and Region C showed no significant changes, while the concentrations in Region A increased markedly. The analysis of the meteorological factors showed that the fluctuations of the annual mean Chl-a concentrations in Region B and Region C were mainly affected by annual precipitation, suggesting that the Chl-a concentrations of these two regions are dominated by the intensity of the lake flow. The annual mean Chl-a concentrations of Region A showed a strong negative correlation with the annual mean wind speed. The descending trend of the annual wind speed may enhance the eutrophication degree of this region, threatening the safety of the water quality of the South-North Water Transfer Project. The Chl-a concentrations showed a strong positive correlation with the distance from the Huaihe Estuary in the wet season suggesting that the Huaihe River has an obvious inhibitory effect on algal biomass in Lake Hongze during this period.

Brain metastasis in a patient with melanoma receiving Pembrolizumab therapy: A case report and review of the literature.

RATIONALE: Melanoma with brain metastasis is associated with a poor prognosis and high mortality rate. As patients with this condition have been excluded from most clinical trials, data on the use of anti-programmed death 1 therapy for these patients are limited. PATIENT CONCERNS: The patient was a 62-year-old man with a 10-year history of melanotic nevus in his right forearm. He was admitted to another hospital in August 2015 due to the growth of the melanotic nevus over 1 year and complaint of a mass in the right mid-axillary area. The patient had no relevant medical, surgical, or family history. DIAGNOSES: The biopsy of his right axillary lymph node showed malignant melanoma. INTERVENTIONS: He was subsequently treated with adjuvant high-dose interferon after dacarbazine. Numerous metastatic lesions were found in his lung, abdomen, pelvic cavity, and brain after five months later, and then Pembrolizumab was used for six cycles (2 mg/kg every 3 weeks). He experienced immunorelated adverse events and we gave him cortisol to treat immunorelated disease until pneumonia was found. OUTCOMES: We observed a delayed effect after three cycles of Pembrolizumab, the intracranial lesion presented clear margins and localization, while the other lesions became much smaller. A mixed response was observed after four cycles, with still stable extracranial metastases but growing a new lesion in brain. After two additional cycles of Pembrolizumab, the treatment was stopped due to the patient's inability to pay for it and a decline in his performance status. He then received palliative treatment at a local hospital and died for severe pulmonary infection, with an overall survival time of 7 months from metastasis. LESSONS: In the case reported here, a delayed and mixed response was observed after Pembrolizumab was used. Because of causing severe pulmonary infection, the use of steroids should be considered carefully when treating immunorelated adverse events. It seemed that the Pembrolizumab has a positive effect on melanoma brain metastases especially combined with other treatments. However, there are still some challenges including patient selection, predictors of response, drug tolerance, optimizing combination strategies and control of adverse effects. More carefully designed clinical trials are urgently needed.

Isoform switching and exon skipping induced by the DNA methylation inhibitor 5-Aza-2'-deoxycytidine.

DNA methylation in gene promoters leads to gene silencing and is the therapeutic target of methylation inhibitors such as 5-Aza-2'-deoxycytidine (5-Aza-CdR). By analyzing the time series RNA-seq data (days 5, 9, 13, 17) obtained from human bladder cells exposed to 5-Aza-CdR with 0.1 uM concentration, we showed that 5-Aza-CdR can affect isoform switching and differential exon usage (i.e., exon-skipping), in addition to its effects on gene expression. We identified more than 2,000 genes with significant expression changes after 5-Aza-CdR treatment. Interestingly, 29 exon-skipping events induced by treatment were identified and validated experimentally. Particularly, exon-skipping event in Enhancer of Zeste Homologue 2 (EZH2) along with expression changes showed significant down regulation on Day 5 and Day 9 but returned to normal level on Day 13 and Day 17. EZH2 is a component of the multi-subunit polycomb repressive complex PRC2, and the down-regulation of exon-skipping event may lead to the regain of functional EZH2 which was consistent with our previous finding that demethylation may cause regain of PRC2 in demethylated regions. In summary, our study identified pervasive transcriptome changes of bladder cancer cells after treatment with 5-Aza-CdR, and provided valuable insights into the therapeutic effects of 5-Aza-CdR in current clinical trials.

Specific and functional diversity of endophytic bacteria from pine wood nematode Bursaphelenchus xylophilus with different virulence.

Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is one of the most devastating diseases of Pinus spp. The PWN was therefore listed as one of the most dangerous forest pests in China meriting quarantine. Virulence of the PWN is closely linked with the spread of PWD. However, main factors responsible for the virulence of PWNs are still unclear. Recently epiphytic bacteria carried by PWNs have drawn much attention. But little is known about the relationship between endophytic bacteria and virulence of B. xylophilus. In this research, virulence of ten strains of B. xylophilus from different geographical areas in six provinces of China and four pine species were tested with 2-year-old seedlings of Pinus thunbergii. Endophytic bacteria were isolated from PWNs with different virulence to investigate the relationship between the bacteria and PWN virulence. Meanwhile, the carbon metabolism of endophytic bacteria from highly and low virulent B. xylophilus was analyzed using Biolog plates (ECO). The results indicated that ten strains of PWNs showed a wide range of virulence. Simultaneously, endophytic bacteria were isolated from 90% of the B. xylophilus strains. The dominant endophytic bacteria in the nematodes were identified as species of Stenotrophomonas, Achromobacter, Ewingella, Leifsonia, Rhizobium, and Pseudomonas using molecular and biochemical methods. Moreover, S. maltophilia, and A. xylosoxidans subsp. xylosoxidans were the predominant strains. Most of the strains (80%) from P. massoniana contained either S. maltophilia, A. xylosoxidans, or both species. There was a difference between the abilities of the endophytic bacteria to utilize carbon sources. Endophytic bacteria from highly virulent B. xylophilus had a relatively high utilization rate of carbohydrate and carboxylic acids, while bacteria from low virulent B. xylophilus made better use of amino acids. In conclusion, endophytic bacteria widely exist in B. xylophilus from different pines and areas; and B. xylophilus strains with different virulence possessed various endophytic bacteria and diverse carbon metabolism which suggested that the endophytic bacteria species and carbon metabolism might be related with the B. xylophilus virulence.

[18S-ITS1 sequence of rRNA in bivalves and its application in phylogenetic analysis].

Bivalves constitute a dominant and diverse group of marine animals in China, most of them are of major commercial important species, and studies of their genetic diversity are necessary for the sustainable exploitation and conservation of these bioresources. The objective of the present work is to explore the feasibility of using the ribosomal RNA as a molecular marker for studying the interspecific and intraspecific genetic variations among bivalves. The 18S-ITS1 sequences of 11 individuals at differing taxonomic levels were determined. The sequence were found to exhibit a high degree of length polymorphism among different species, ranging from 558 bp in C.farreri to 784 bp in O. rivularis, mainly resulting from the variation of ITS1, and the percent divergence ranging from 10.7% to 61.7%. The NJ (neighbor-joining) tree inferred from 18S fragment agrees with the previous study based on morphologies and chemical analysis well. The sequence variation was found to vary among 4 individuals of P. martensi (0.6% approximately 1.9%), collected from 4 geographical sites, which involved substitutions,transversion as well as insertions and deletions. All these results show that ITS1 is highly divergent among different species of bivalves and could be used in classification and distinguishing closely related species, and also could be used for molecular systematic studies at relative species, subspecies and population levels.