Effects of transgenic Bt rice on the active rhizospheric methanogenic archaeal community as revealed by DNA-based stable isotope probing

AIMS

This study aimed to investigate the influence of planting Cry1Ab/Cry1Ac gene expressing rice (Bt rice) on rhizospheric active methanogenic archaeal communities.

METHODS AND RESULTS

The nontransgenic parental line was used as the control (Ck rice). DNA-based stable isotope probing (DNA-SIP) technology traced the rhizospheric active methanogens at the tillering stage. The results revealed significantly lower CH₄ emission flux from Bt soil than that from Ck soil during the whole growth period. The active methanogenic community composition remained stable. The RC-I lineage (77·9-79·8%) and Methanosaetaceae (13·9-15·1%) were the predominant active methanogens in Bt and Ck rice rhizospheres. However, the abundance of functionally active methanogens in the Bt rice rhizosphere was significantly reduced. Lower levels of root exudates (that included carbohydrate and organic acids) from Bt rice were also detected at the tillering stage.

CONCLUSION

This study found that the genetic modification of rice reduced the potential methanogenic substrates came from plant-derived root exudates, which represented an important factor in reducing CH₄ generation and active methanogenic archaeal abundance in Bt rhizosphere soil.

SIGNIFICANCE AND IMPACT OF THE STUDY

The effect of genetically modified (GM) insect-resistant crops on soil micro-organisms has become an issue of public concern, especially the indirect effect of plant metabolisms caused by the insertion of foreign genes. Methanogenesis, which is regarded as a critical ecological process in paddy soil, is influenced by plant root exudates; these are mainly derived from photosynthesis. The variations in root exudates across the Bt and Ck rice suggested the indirect influence of foreign gene insertion. DNA-SIP successfully traced the active methanogenic archaeal populations assimilating ¹³ C-labelled photosynthetic carbon and found a strong influence of planting Bt rice on active methanogens. As a consequence, we proposed that analysis of functionally active micro-organisms is more suitable for monitoring and predicting the environmental influence of GM plants.

The challenge of acquiring a satisfactory EBSD result of CWSR Zircaloy-4 cladding tube

This work presents a methodology combining SEM, EDS, conventional EBSD, and transmission-EBSD to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding in unprecedented detail. Second-phase precipitates (SPPs) in Zircaloy-4 specimens were revealed after chemical polishing using a solution containing hydrofluoric acid (HF). Pitting corrosion of Zircaloy-4 specimens was revealed after electropolishing using an electrolyte containing HClO₄ . A zirconium coupon without SPPs was used to confirm the chemical response of SPPs on surface morphology. Intrinsic features of cold-worked Zircaloy-4 such as relatively small grain sizes, high dislocation density, and complex microstructure make it significantly more difficult to collect excellent EBSD results compared to recrystallised Zircaloy-4. The fine hydride structure of as-hydrided CWSR Zircaloy-4 cladding further increases the level of challenge on EBSD analysis.

LAY DESCRIPTION

We present a methodology combining multiple microscopic methods to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding, important alloys of structural materials widely used in nuclear application, and emphasis on the challenge of acquiring a satisfactory electron backscatter diffraction (EBSD) result of CWSR Zircaloy-4 cladding material in great details. EBSD is a powerful technique to characterise the crystallographic distribution and lattice type of conductive crystalline materials, especially for a highly textured material like CWSR Zircaloy-4 alloy. However, zirconium alloys are known to be one of the most difficult materials to prepare for EBSD characterisation. We point out that the configuration of the microstructure of the specimen cause the challenge in the EBSD sample preparations. Moreover, the occurrence of tiny zirconium hydride precipitates in Zircaloy-4 increases the difficulty. We believe that the information of the EBSD sample preparation related results in this paper can provide researchers and scientists in this community a useful reference to speed up the EBSD sample preparation of CWSR Zircaloy-4 cladding material and to expect the corresponding EBSD results.

[CD137-CD137L signaling influences the autophagy via JNK pathway in mouse vascular smooth muscle cells]

Objective: To investigate whether CD137-CD137L signaling can affect the autophagy of mouse vascular smooth muscle cells(VSMCs) through JNK signal pathway. Methods: Primary culture of C57BL/6J mouse thoracic aorta VSMCs was performed by tissue block adherence method. VSMCs between the third to fifth passages were isolated and cultured. VSMCs were divided into 4 groups: control group, CD137 agonist group, JNK inhibition group, and DMSO group. VSMCs in CD137 agonist group were treated with recombinant protein of CD137L (10 μg/ml), VSMCs in JNK inhibition group were treated with JNK inhibitor SP600125 (10 μmol/L) for 30 minutes followed by recombinant protein of CD137L (10 μg/ml) and DMSO group was treated with the same amount of DMSO in JNK inhibition group for 30 minutes, then added recombinant protein of CD137L (10 μg/ml). Western blot was used to detect the protein expression of p-JNK, LCⅡ and p62 in each group. Fluorescence microscopy was used to track the changes of autophagy in cells which was infected with adenovirus expressing tandem mRFP-GFP-LC3. Transmission electron microscope (TEM) was used to observe intracellular autophagosomes and autolysosomes. Results: (1) Compared with the control group, stimulating CD137-CD137L axis by recombinant protein of CD137L significantly upregulated the expression of p-JNK, LCⅡ and p62 (1.15±0.19 vs. 0.72±0.21, P<0.05;1.03±0.13 vs. 0.59±0.15, P<0.05, and 1.10±0.19 vs. 0.76±0.15, P<0.05). These effects could be reduced by JNK inhibitor (0.61±0.21 vs. 1.15±0.19, P<0.05;0.74±0.11 vs. 1.03±0.13, P<0.05, and 0.21±0.12 vs. 1.10±0.19, P<0.05). The expression of these proteins in DMSO group remained unchanged compared with CD137 agonist group (P>0.05). (2) Changes of autophagy in cells of various group: the number of total fluorescent spots and yellow fluorescent spots in CD137 agonist group was significantly increased compared to control group (total fluorescent spots:(93.00±14.11)/cell vs. (52.33±9.61)/cell, P<0.05, and (64.33±6.81)/cell vs. (25.67±3.51)/cell, P<0.05), moreover, the number of yellow fluorescent spots was higher than the red fluorescent spots fluorescent spots in CD137 agonist group. Compared with CD137 agonist group, pretreatment with JNK inhibitor significantly reduced the number of total fluorescent spots and yellow fluorescent spots ((53.00±3.17)/cell vs. (93.00±14.11)/cell, P<0.05,and (15.33±4.51)/cell vs. (64.33±6.81)/cell, P<0.05). The red fluorescent spots were higher than the yellow fluorescent spots in JNK inhibition group. The number of total fluorescent spots and yellow fluorescent spots in CD137 agonist group was not affected by pretreatment with DMSO (P>0.05). (3) The number of intracellular autophagosomes and autolysosomes was significantly higher in CD137 agonist group than in control group((17.67±6.03)/cell vs. (5.67±2.52)/cell, P<0.05), and the number of autophagosomes was higher than that of autolysosomes in CD137 agonist group((14.00±4.00)/cell vs. (3.67±2.08)/cell, P<0.05). The number of intracellular autophagosomes and autolysosomes was significantly lower in JNK inhibition group compared to CD137 agonist group((5.67±4.04)/cell vs. (17.67±6.03)/cell, P<0.05) and the number of autophagosomes was lower than that of autolysosomes in JNK inhibition group((1.33±1.53)/cell vs. (4.33±2.52)/cell, P<0.05). The number of intracellular autophagosomes and autolysosomes was similar between DMSO group and CD137 agonist group (P>0.05). Conclusion: CD137-CD137L signal may influence autophagy of mouse VSMCs via JNK pathway.

Biological traits and the complex of parasitoids of the elm pest Orchestes steppensis (Coleoptera: Curculionidae) in Xinjiang, China

The flee-weevil Orchestes steppensis Korotyaev (Coleoptera: Curculionidae) is a steppe eastern Palaearctic species, notable as a serious pest of elms (Ulmus spp., Ulmaceae), by feeding on the leaves (adults) or mining them heavily (larvae), especially of Ulmus pumila L. in Xinjiang, China. We have corrected the previous misidentifications of this weevil in China as O. alni (L.) or O. mutabilis Boheman and demonstrated that it is likely to be an invasive species in Xinjiang. Prior to this study, natural enemies of O. steppensis were unknown in Xinjiang. Resulting from field investigation and rearing in the laboratory during 2013-2016, seven parasitoid species were found to be primary and solitary, attacking larval and pupal stages of the host weevil. Pteromalus sp. 2 is the dominant species and also is the most competitive among the seven parasitoids, which could considered to be a perspective biological control agent of O. steppensis. Yet, the current control of this pest by the local natural enemies in Xinjiang is still currently inefficient, even though in 2016 parasitism was about 36% on U. pumila in Urumqi, so the potential for a classical biological control program against it needs to be further investigated, including an assessment of its parasitoids and other natural enemies in the native range of O. steppensis. The presented information on the natural enemies of this weevil can be also important for a potential classical biological control program against it in North America (Canada and USA), where it is a highly damaging and rapidly spreading invasive species.

Decreased Expression of MYPT1 Contributes to Tumor Angiogenesis and Poor Patient Prognosis in Human Prostate Cancer

BACKGROUND

Our previous study demonstrated that Myosin Phosphatase Targeting subunit 1 (MYPT1) may function as a direct target of microRNA-30d, which promotes tumor angiogenesis and tumor growth of prostate cancer (PCa). Here, we aimed to investigate the clinical significance of MYPT1 expression and its functions in PCa.

METHODS

Roles of MYPT1 deregulation in tumor angiogenesis of PCa was determined in vitro and in vivo experiments. Expression patterns of MYPT1 and CD31 proteins were examined by immunohistochemistry and immunofluorescence, respectively. Associations of MYPT1/CD31 combination with various clinicopathological features and patients' prognosis of PCa were also statistically evaluated.

RESULTS

Through gain- and loss-of-function experiments, MYPT1 inhibited capillary tube formation of endothelial cells and in vivo tumor angiogenesis in a mouse model with the downregulation of VEGF and CD31 expression. In addition, MYPT1 expression was significantly decreased, while CD31 expression was dramatically increased in PCa tissues compared to benign prostate tissues. Notably, MYPT1 expression levels in PCa tissues were negatively correlated with that of CD31. Statistically, MYPT1-low/CD31- high expression was distinctly associated with high Gleason score, positive biochemical recurrence, and reduced overall survival of PCa patients. Moreover, PCa patients with MYPT1-low/CD31-high expression more frequently had shorter overall, biochemical recurrence-free and metastasis-free survivals. MYPT1/CD31 combination was identified as an independent factor to predict biochemical recurrence-free and metastasis-free survivals of PCa patients.

CONCLUSIONS

Our findings indicate that MYPT1 may inhibit angiogenesis and contribute favorable prognosis in PCa patients, implying that MYPT1 might be a potential drug candidate in anticancer therapy.

[CD137 signaling promotes the formation of plaque calcification via inhibiting the fusion of autophagy and lysosomal in Apo E(-/-) mice]

Objective: To investigate whether CD137 signaling promoted the formation of atherosclerotic plaque calcification by inhibiting the fusion of autophagosome and lysosome. Methods: (1) In vivo, CD137 agonist antibody and anti-CD137 antibody were used to stimulate and inhibit the CD137 signaling, respectively. Fifteen Apo E(-/-) mice were randomly divided into three groups: control group (intraperitoneal injection of IgG2b 200 µg) , CD137 agonist group (intraperitoneal injection of CD137 agonist antibody 200 µg) , anti-CD137 group (pretreatment with 200 µg anti-CD137 antibody for 24 hours, then injection of CD137 agonist antibody) . (2) In vitro, primary culture of mouse aortic VSMCs obtained through adherence methods for tissues explants. The cells was divided into three groups: control group, agonist-CD137 group (CD137 agonist antibody 10 μg/ml) , and anti-CD137 group (pretreatment with 10 μg/ml anti-CD137 antibody for 60 minutes, then incubated with 10 μg/ml CD137 agonist antibody) . Von kossa staining was used to detect the calcification in the cell and plaque. Immunohistochemical staining was used to observe the expression of LC3B, Beclin 1 and p62 which are associated with autophagy. The levels of autophagy related protein (LC3) , Beclin 1, p62, and the expression of Runx2 and bone morphogenetic protein 2, which is associated with osteogenic differentiation in the VSMCs, were determined by Western blot. The autophagy flow of each group was detected by fluorescence microscopy. The autophagy was observed by transmission electron microscope in vivo and in vitro. Results: (1) In vivo, the calcified plaque area in CD137 agonist group was significantly larger than that in the control group (3.01%±0.45% vs. 0.27%±0.06%, P<0.01) , and calcified plaque area in anti-CD137 group was significantly smaller compared with that in the CD137 agonist group (1.23%±0.39% vs. 3.01%±0.45%, P<0.05) . Immunohistochemical staining showed that the expression of early autophagy marker protein LC3B and Beclin 1 were significantly upregulated in CD137 agonist group and anti-CD137 group than in control group, and the highest expression was observed in CD137 agonist group (P<0.05) . The expression of advanced autophagy marker protein p62 was higher in the CD137 agonist group than in the anti-CD137 group (P<0.05) . (2) In vitro, the ratio of autophagy related protein LC3 Ⅱ/Ⅰ and p62 protein expression were significantly higher in CD137 agonist group and anti-CD137 group than in control group (P<0.01) , while the expression of p62 protein was significantly higher in CD137 agonist group than that in anti-CD137 group (P<0.05) . In the cell calcification inducing experiment, the expression of BMP-2 and Runx2 protein was significantly higher in CD137 agonist group than that in control group (P<0.01) , but the levels of BMP-2 and Runx2 protein were lower in anti-CD137 group than in CD137 agonist group (P<0.05) . Conclusion: Our results indicate that activation of CD137 signaling can promote the formation of atherosclerotic plaque calcification by inhibiting the fusion of autophagosome and lysosome.

[Impact of CD137-CD137L signaling mediated exocytosis of autophagosome within vascular smooth muscle cells on the formation of atherosclerotic calcification]

Objective: To explore whether CD137-CD137L signaling mediated exocytosis of autophagosome within vascular smooth muscle cells (VSMCs) could influence the formation of atherosclerotic calcification. Methods: Fifteen 8-week-old male ApoE(-/-)(C57BL/6J-KO) mice fed with high fat diet for 5 weeks were randomly divided into three groups by using stochastic indicator method as follows: control group, n=5; agonist-CD137 group: agonist-CD137 antibody 200 μg/2 weeks for 4 weeks, ip, n=5; anti-CD137 group: 200 μg anti-CD137 antibody+ 200 μg agonist-CD137 antibody/2 weeks for 4 weeks, ip, n=5. Von Kossa staining was applied to observe the calcification of the thoracic aortic atherosclerotic plaque in each group. Immunohistochemistry was used to detect the expression of LC3 and Beclin1 which were the autophage markers of early-to-mid stage; Western blot was adopted to quantify protein level of microtubule-associated proteins 1 light chain 3B(LC3B) and mammalian ortholog of the yeast autophagy-related gene 6 (Beclin1). Transmission electron microscope (TME) was used to observe the formation of autophagosome in plaque. C57BL/6J mouse VSMCs were cultured by using tissue piece inoculation method. Groups of in vitro studies were the same as in vivo study: control group, agonist-CD137 group, anti-CD137 group, the agonist-CD137 groups was treated with agonist-CD137 antibody (10 μg/ml) and anti-CD137 group was treated with anti-CD137 antibody (10 μg/ml) for 30 minutes, followed by agonist-CD137 antibody (10 μg/ml). Von Kossa staining and osteogenesis phenotypic alkaline phosphatase (ALP) activity detection were adopted to observe calcification in VSMCs. Autophagosomes were separated from the supernatant of the agonist-CD137 group with density gradient centrifugation method. VSMCs were divided into two groups: positive group (containing complete medium with above autophagosomes to a final concentration 15 μg/ml) and negative group (only complete medium) after being pretreated with mixed inflammatory cytokines (IL-1β、IFN-γ and TNF-α, final concentration was 25 ng/ml respectively) for 24 hours and calcium deposition and osteogenesis phenotypic marker bone morphogenetic protein 2(BMP2) were then detected. Results: (1) Compared with the control group, activation of the CD137-CD137L signal significantly increased the formation of calcification area in thoracic aortic atherosclerotic plaque of ApoE(-/-) mice((1.82±0.15)×10(4) μm(2) vs. (0.34±0.08)×10(4) μm(2,) P<0.01), this effect was significantly attenuated by inhibiting this signal ((0.83±0.30)×10(4) μm(2) vs. (1.82±0.15)×10(4) μm(2,) P<0.05); positive autophagy makers LC3B and Beclin1 were detected in both agonist-CD137 group and anti-CD137 groups and the expression of LC3B and Beclin1 was substantially higher in anti-CD137 group. Western blot analysis indicated that the expression of LC3B and Beclin1 in agonist-CD137 group was significantly upregulated compared with the control group (0.17±0.01 vs. 0.03±0.08, P<0.05, and 0.12±0.02 vs. 0.06±0.02, P<0.05), which could be significantly downregulated in anti-CD137 group (0.28±0.09 vs. 0.17±0.01, P<0.05 and 0.17±0.02 vs. 0.12±0.02, P<0.05). TME showed that the number (QTY /HP) of autophagosome of agonist-CD137 group and anti-CD137 group in plaque were both increased (14.67±2.52 vs. 3.67±1.53, P<0.01, and 15.33±2.08 vs. 3.67±1.53, P<0.01), while in the agonist-CD137 group, the number of extracellular autophagosome within thoracic aortic atherosclerotic plaque of ApoE(-/-) mice increased more substantially (5.33±1.53 vs. 1.33±0.58, P<0.01). (2) In vitro study showed that activating CD137-CD137L signal could promote calcium deposition in extracellular matrix and the activity of osteogenesis phenotypic ALP((6.73±0.02) μmol/mg protein vs. (1.07±0.03) μmol/mg protein, P<0.05), and ((563.20±0.72) U/mg protein vs. (117.50±0.64) U/mg protein, P<0.05), while these effects were significantly blunted in anti-CD137 group ((1.94±0.05) μmol/mg protein vs. (6.73±0.02) μmol/mg protein, P<0.05, and (236.10±0.14) U/mg protein vs. (563.20±0.72) U/mg protein, P<0.05). TME showed that the number of intracellular autophagosome in agonist-CD137 group and anti-CD137 group was both significantly higher than in control group ((21.65±1.34) μg/ml vs. (8.32±1.58) μg/ml, P<0.01, and (15.42±1.65) μg/ml vs. (8.32±1.58) μg/ml, P<0.05). After the density gradient centrifugation, exocytotic autophagosome in the medium of agonist-CD137 group was markedly higher than in control group ((14.67±1.53) μg/ml vs. (2.33±1.15) μg/ml, P<0.01). (3) Compared with the control group, autophagosomes isolated from culture supernatant (final concentration: 15 μg/ml) could significantly stimulate calcium deposition((2.30±0.10) μmol/mg protein vs. (0.15±0.40) μmol/mg protein, P<0.05) and enhance the expression of bone morphogenetic protein 2 (2.10±0.04 vs. 0.30±0.01, P<0.05). Conclusion: CD137-CD137L signaling could mediate exocytosis of autophagosome within VSMCs, thus influence the formation of atherosclerotic calcification.

[Research on the effect of iodinate contrast agent on the DNA radiation damage at CT]

Objective: To evaluate the effect of iodinate contrast agent (ICA) on the formation of DNA double-stand breaks (DSBs) in human peripheral blood lymphocytes during computed tomography (CT) examinations. Methods: Peripheral venous blood (16 ml/person) of 36 volunteers were collected during the period of February to May 2016. Each blood sample was divided into 8 tubes and 4 groups on average, which were marked as groups of A, B, C, D randomly. 25 μl ICA was respectively added into one tube of each group and the groups of B, C, D accepted the same CT scan for once, twice and three times. The lymphocytes in these blood samples were separated by using density-gradient centrifugation, fixed and immunostained with γH2AX antibody. The average number of phosphorylated histone H2AX (γH2AX) foci per lymphocyte was counted under a fluorescence microscopy. Results: The numbers of γH2AX foci were increased approximately 82.9% ((0.064±0.025) vs (0.035±0.010) foci/cell) if ICA was simply added into the blood. With the increase of CT radiation, the foci numbers of the groups of B, C, D would increase and the samples containing ICA could have a more amount of foci numbers than those without ICA (B: (1.217±0.158) vs (0.774±0.258); C: (2.128±0.185) vs (1.569±0.201); D: (3.812±0.490) vs (2.938±0.480) foci/cell). The more radiation it had, the more significant the difference of foci numbers would be ((0.489±0.323), (0.549±0.278), (0.692±0.462) foci/cell). Conclusion: The ICA itself can lead to an increase of the DSBs level and the application of ICA can amplify the DNA damage as assessed with γH2AX foci formation during diagnostic X-ray procedures.

Primary diffuse large B-cell lymphoma of the frontal sinus

Primary frontal sinus lymphoma is a rare disease, with the presenting symptoms that are secondary to the tumor mass effect and often misleading. Here we describe the case of a 43-year-old male patient who presented with a 4-week history of a gradually enlarging painful diffuse swelling over the right frontal sinus region. We report the clinical presentation, differential diagnosis and treatment of the case. We also reviewed the available literature on the diffuse large B-cell lymphoma in the frontal sinus region. The article emphasizes the importance of early recognition of this rare disease.